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Sample records for accurately reflect current

  1. Accurate diffuse reflection measurements in the infrared spectral range.

    PubMed

    Richter, W; Erb, W

    1987-11-01

    A sphere arrangement for directional-hemispherical reflectance measurements in the 1-15-microm wavelength range is tested for its accuracy. Comparative measurements with the fundamental PTB sphere reflectometer in the overlapping spectral range between 1.0 and 1.1 microm indicate no systematic measurement uncertainties of the new device. The uncertainty of the reflectance measured by it is therefrom deduced to be +/-0.01 for the 1-5.6-microm wavelength range. PMID:20523415

  2. New Claus catalyst tests accurately reflect process conditions

    SciTech Connect

    Maglio, A.; Schubert, P.F.

    1988-09-12

    Methods for testing Claus catalysts are developed that more accurately represent the actual operating conditions in commercial sulfur recovery units. For measuring catalyst activity, an aging method has been developed that results in more meaningful activity data after the catalyst has been aged, because all catalysts undergo rapid initial deactivation in commercial units. An activity test method has been developed where catalysts can be compared at less than equilibrium conversion. A test has also been developed to characterize abrasion loss of Claus catalysts, in contrast to the traditional method of determining physical properties by measuring crush strengths. Test results from a wide range of materials correlated well with actual pneumatic conveyance attrition. Substantial differences in Claus catalyst properties were observed as a result of using these tests.

  3. Accurate Measurements of Spectral Reflectance in Picasso's Guernica Painting.

    PubMed

    de Luna, Javier Muñoz; Fernandez-Balbuena, Antonio Alvarez; Vázquez, Daniel; Melgosa, Manuel; Durán, Humberto; García, Jorge; Muro, Carmen

    2016-01-01

    The use of non-invasive spectral measurements to control the conservation status is a part of the preventive conservation of artworks which nowadays is becoming increasingly interesting. This paper describes how to use a spectral measuring device and an illumination system specifically designed for such a task in a very large dimension artwork painting (7.8 m wide × 3.5 m high). The system, controlled by a Cartesian robot, allows spectral measurements in a spectral range of 400-780 nm. The measured data array has a total of 2201 circular regions with 5.5 mm spot diameter placed on a square grid. Colorimetric calculations performed from these spectral measurements may be used to characterize color shifts related to reflectance changes in specific areas of the paint. A color shifting from the expected gray has been shown. PMID:26767640

  4. An accurate continuous calibration system for high voltage current transformer

    SciTech Connect

    Tong Yue; Li Binhong

    2011-02-15

    A continuous calibration system for high voltage current transformers is presented in this paper. The sensor of this system is based on a kind of electronic instrument current transformer, which is a clamp-shape air core coil. This system uses an optical fiber transmission system for its signal transmission and power supply. Finally the digital integrator and fourth-order convolution window algorithm as error calculation methods are realized by the virtual instrument with a personal computer. It is found that this system can calibrate a high voltage current transformer while energized, which means avoiding a long calibrating period in the power system and the loss of power metering expense. At the same time, it has a wide dynamic range and frequency band, and it can achieve a high accuracy measurement in a complex electromagnetic field environment. The experimental results and the on-site operation results presented in the last part of the paper, prove that it can reach the 0.05 accuracy class and is easy to operate on site.

  5. An accurate continuous calibration system for high voltage current transformer.

    PubMed

    Tong, Yue; Li, Bin Hong

    2011-02-01

    A continuous calibration system for high voltage current transformers is presented in this paper. The sensor of this system is based on a kind of electronic instrument current transformer, which is a clamp-shape air core coil. This system uses an optical fiber transmission system for its signal transmission and power supply. Finally the digital integrator and fourth-order convolution window algorithm as error calculation methods are realized by the virtual instrument with a personal computer. It is found that this system can calibrate a high voltage current transformer while energized, which means avoiding a long calibrating period in the power system and the loss of power metering expense. At the same time, it has a wide dynamic range and frequency band, and it can achieve a high accuracy measurement in a complex electromagnetic field environment. The experimental results and the on-site operation results presented in the last part of the paper, prove that it can reach the 0.05 accuracy class and is easy to operate on site. PMID:21361633

  6. An accurate dynamical electron diffraction algorithm for reflection high-energy electron diffraction

    NASA Astrophysics Data System (ADS)

    Huang, J.; Cai, C. Y.; Lv, C. L.; Zhou, G. W.; Wang, Y. G.

    2015-12-01

    The conventional multislice method (CMS) method, one of the most popular dynamical electron diffraction calculation procedures in transmission electron microscopy, was introduced to calculate reflection high-energy electron diffraction (RHEED) as it is well adapted to deal with the deviations from the periodicity in the direction parallel to the surface. However, in the present work, we show that the CMS method is no longer sufficiently accurate for simulating RHEED with the accelerating voltage 3-100 kV because of the high-energy approximation. An accurate multislice (AMS) method can be an alternative for more accurate RHEED calculations with reasonable computing time. A detailed comparison of the numerical calculation of the AMS method and the CMS method is carried out with respect to different accelerating voltages, surface structure models, Debye-Waller factors and glancing angles.

  7. Parameter Estimation of Ion Current Formulations Requires Hybrid Optimization Approach to Be Both Accurate and Reliable

    PubMed Central

    Loewe, Axel; Wilhelms, Mathias; Schmid, Jochen; Krause, Mathias J.; Fischer, Fathima; Thomas, Dierk; Scholz, Eberhard P.; Dössel, Olaf; Seemann, Gunnar

    2016-01-01

    Computational models of cardiac electrophysiology provided insights into arrhythmogenesis and paved the way toward tailored therapies in the last years. To fully leverage in silico models in future research, these models need to be adapted to reflect pathologies, genetic alterations, or pharmacological effects, however. A common approach is to leave the structure of established models unaltered and estimate the values of a set of parameters. Today’s high-throughput patch clamp data acquisition methods require robust, unsupervised algorithms that estimate parameters both accurately and reliably. In this work, two classes of optimization approaches are evaluated: gradient-based trust-region-reflective and derivative-free particle swarm algorithms. Using synthetic input data and different ion current formulations from the Courtemanche et al. electrophysiological model of human atrial myocytes, we show that neither of the two schemes alone succeeds to meet all requirements. Sequential combination of the two algorithms did improve the performance to some extent but not satisfactorily. Thus, we propose a novel hybrid approach coupling the two algorithms in each iteration. This hybrid approach yielded very accurate estimates with minimal dependency on the initial guess using synthetic input data for which a ground truth parameter set exists. When applied to measured data, the hybrid approach yielded the best fit, again with minimal variation. Using the proposed algorithm, a single run is sufficient to estimate the parameters. The degree of superiority over the other investigated algorithms in terms of accuracy and robustness depended on the type of current. In contrast to the non-hybrid approaches, the proposed method proved to be optimal for data of arbitrary signal to noise ratio. The hybrid algorithm proposed in this work provides an important tool to integrate experimental data into computational models both accurately and robustly allowing to assess the often non

  8. Return stroke current reflections in rocket-triggered lightning

    NASA Astrophysics Data System (ADS)

    Caicedo, J. A.; Biagi, C.; Uman, M. A.; Jordan, D. M.; Hare, B.

    2016-03-01

    Ten upward propagating return stroke currents in eight triggered lightning flashes have been observed to reflect downward from 140 to 300 m altitude by way of measurements of the channel base current, close electric field and electric field derivative, and high-speed video. The current reflections appear as dips in the measured channel base current and in the electric fields and as bipolar pulses in the electric field derivative waveforms. The current dips occur 2.7 to 13.9 μs after the initiation of the return stroke current at ground. The observed phenomenon results from a portion of the upward propagating return stroke current wave being reflected from a channel impedance discontinuity apparently associated with an isolated section of unexploded triggering wire, as inferred from high-speed video records. A transmission line model is used to model the close electric field and electric field derivative of the postulated initial and reflected current waves, starting with the measured channel base current, and the results are compared favorably with measurements made at 92 to 326 m. From the measured time between the return stroke current initiation at the ground and the time the current reflection reaches the channel base and produces the current dip, along with the reflection height inferred from the video records, we find the average of the upward and downward reflected return stroke current speed for each of the 10 strokes to be between 0.81 and 2.06 × 108 m s-1.

  9. Montessori Elementary Philosophy Reflects Current Motivation Theories

    ERIC Educational Resources Information Center

    Murray, Angela

    2011-01-01

    Montessori's theories, developed more than 100 years ago, certainly resonate with current psychological research on improving education. Autonomy, interest, competence, and relatedness form the foundation for three contemporary efforts to organize the vast literature on motivation into a parsimonious theory. These four elements also comprise…

  10. Leap of Faith: Does serum luteinizing hormone always accurately reflect central reproductive neuroendocrine activity?

    PubMed Central

    Moenter, Suzanne M.

    2015-01-01

    Function of the central aspects of the hypothalamo-pituitary-gonadal axis has been assessed in a number of ways including direct measurements of hypothalamic output and indirect measures using gonadotropin release from the pituitary as a bioassay for reproductive neuroendocrine activity. Here, methods for monitoring these various parameters are briefly reviewed and then examples presented of both concordance and discrepancy between central and peripheral measurements, with a focus on situations in which elevated GnRH neurosecretion is not reflected accurately by pituitary luteinizing hormone release. Implications for interpretation of gonadotropin data are discussed. PMID:26278916

  11. Measuring solar reflectance Part I: Defining a metric that accurately predicts solar heat gain

    SciTech Connect

    Levinson, Ronnen; Akbari, Hashem; Berdahl, Paul

    2010-05-14

    Solar reflectance can vary with the spectral and angular distributions of incident sunlight, which in turn depend on surface orientation, solar position and atmospheric conditions. A widely used solar reflectance metric based on the ASTM Standard E891 beam-normal solar spectral irradiance underestimates the solar heat gain of a spectrally selective 'cool colored' surface because this irradiance contains a greater fraction of near-infrared light than typically found in ordinary (unconcentrated) global sunlight. At mainland U.S. latitudes, this metric RE891BN can underestimate the annual peak solar heat gain of a typical roof or pavement (slope {le} 5:12 [23{sup o}]) by as much as 89 W m{sup -2}, and underestimate its peak surface temperature by up to 5 K. Using R{sub E891BN} to characterize roofs in a building energy simulation can exaggerate the economic value N of annual cool-roof net energy savings by as much as 23%. We define clear-sky air mass one global horizontal ('AM1GH') solar reflectance R{sub g,0}, a simple and easily measured property that more accurately predicts solar heat gain. R{sub g,0} predicts the annual peak solar heat gain of a roof or pavement to within 2 W m{sup -2}, and overestimates N by no more than 3%. R{sub g,0} is well suited to rating the solar reflectances of roofs, pavements and walls. We show in Part II that R{sub g,0} can be easily and accurately measured with a pyranometer, a solar spectrophotometer or version 6 of the Solar Spectrum Reflectometer.

  12. Measuring solar reflectance - Part I: Defining a metric that accurately predicts solar heat gain

    SciTech Connect

    Levinson, Ronnen; Akbari, Hashem; Berdahl, Paul

    2010-09-15

    Solar reflectance can vary with the spectral and angular distributions of incident sunlight, which in turn depend on surface orientation, solar position and atmospheric conditions. A widely used solar reflectance metric based on the ASTM Standard E891 beam-normal solar spectral irradiance underestimates the solar heat gain of a spectrally selective ''cool colored'' surface because this irradiance contains a greater fraction of near-infrared light than typically found in ordinary (unconcentrated) global sunlight. At mainland US latitudes, this metric R{sub E891BN} can underestimate the annual peak solar heat gain of a typical roof or pavement (slope {<=} 5:12 [23 ]) by as much as 89 W m{sup -2}, and underestimate its peak surface temperature by up to 5 K. Using R{sub E891BN} to characterize roofs in a building energy simulation can exaggerate the economic value N of annual cool roof net energy savings by as much as 23%. We define clear sky air mass one global horizontal (''AM1GH'') solar reflectance R{sub g,0}, a simple and easily measured property that more accurately predicts solar heat gain. R{sub g,0} predicts the annual peak solar heat gain of a roof or pavement to within 2 W m{sup -2}, and overestimates N by no more than 3%. R{sub g,0} is well suited to rating the solar reflectances of roofs, pavements and walls. We show in Part II that R{sub g,0} can be easily and accurately measured with a pyranometer, a solar spectrophotometer or version 6 of the Solar Spectrum Reflectometer. (author)

  13. Reflection of Constructivist Theories in Current Educational Practice

    ERIC Educational Resources Information Center

    Juvova, Alena; Chudy, Stefan; Neumeister, Pavel; Plischke, Jitka; Kvintova, Jana

    2015-01-01

    In this overview study, we would like to present the basic constructivist approaches that have affected or influenced the current concept of education. The teacher-student interaction is reflected by personality, psychological traits, attitudes and cultural capital of the participants of the educational process as well as the teacher's effort to…

  14. An Accurate Picture of What Is Currently Happening in Turkish Science Classrooms

    ERIC Educational Resources Information Center

    Yilmaz, Hülya; Türkmen, Hakan

    2007-01-01

    The purpose of this study was to investigate the extent to which primary science teachers understand the new reform implemented in Turkey and to examine their perceptions regarding science instruction. Thus, it could be possible to show an accurate picture of what is currently happening in primary science classrooms and identify the kind of…

  15. Accurate Relations Between the Neutron Current Densities and the Neutron Fluxes

    SciTech Connect

    Ronen, Yigal

    2004-02-15

    Accurate relations between neutron current densities and neutron flux are obtained using the integral transport equation. Using these relations and Fick's Law, diffusion constants can be calculated. These diffusion constants are better than those usually used for the cases in which {sigma}{sub a}/{sigma}{sub s} is not small.

  16. Accurate elevation and normal moveout corrections of seismic reflection data on rugged topography

    USGS Publications Warehouse

    Liu, J.; Xia, J.; Chen, C.; Zhang, G.

    2005-01-01

    The application of the seismic reflection method is often limited in areas of complex terrain. The problem is the incorrect correction of time shifts caused by topography. To apply normal moveout (NMO) correction to reflection data correctly, static corrections are necessary to be applied in advance for the compensation of the time distortions of topography and the time delays from near-surface weathered layers. For environment and engineering investigation, weathered layers are our targets, so that the static correction mainly serves the adjustment of time shifts due to an undulating surface. In practice, seismic reflected raypaths are assumed to be almost vertical through the near-surface layers because they have much lower velocities than layers below. This assumption is acceptable in most cases since it results in little residual error for small elevation changes and small offsets in reflection events. Although static algorithms based on choosing a floating datum related to common midpoint gathers or residual surface-consistent functions are available and effective, errors caused by the assumption of vertical raypaths often generate pseudo-indications of structures. This paper presents the comparison of applying corrections based on the vertical raypaths and bias (non-vertical) raypaths. It also provides an approach of combining elevation and NMO corrections. The advantages of the approach are demonstrated by synthetic and real-world examples of multi-coverage seismic reflection surveys on rough topography. ?? The Royal Society of New Zealand 2005.

  17. High-power CMOS current driver with accurate transconductance for electrical impedance tomography.

    PubMed

    Constantinou, Loucas; Triantis, Iasonas F; Bayford, Richard; Demosthenous, Andreas

    2014-08-01

    Current drivers are fundamental circuits in bioimpedance measurements including electrical impedance tomography (EIT). In the case of EIT, the current driver is required to have a large output impedance to guarantee high current accuracy over a wide range of load impedance values. This paper presents an integrated current driver which meets these requirements and is capable of delivering large sinusoidal currents to the load. The current driver employs a differential architecture and negative feedback, the latter allowing the output current to be accurately set by the ratio of the input voltage to a resistor value. The circuit was fabricated in a 0.6- μm high-voltage CMOS process technology and its core occupies a silicon area of 0.64 mm (2) . It operates from a ± 9 V power supply and can deliver output currents up to 5 mA p-p. The accuracy of the maximum output current is within 0.41% up to 500 kHz, reducing to 0.47% at 1 MHz with a total harmonic distortion of 0.69%. The output impedance is 665 k Ω at 100 kHz and 372 k Ω at 500 kHz. PMID:25073130

  18. All-reflective, highly accurate polarization rotator for high-power short-pulse laser systems.

    PubMed

    Keppler, S; Hornung, M; Bödefeld, R; Kahle, M; Hein, J; Kaluza, M C

    2012-08-27

    We present the setup of a polarization rotating device and its adaption for high-power short-pulse laser systems. Compared to conventional halfwave plates, the all-reflective principle using three zero-phase shift mirrors provides a higher accuracy and a higher damage threshold. Since plan-parallel plates, e.g. these halfwave plates, generate postpulses, which could lead to the generation of prepulses during the subsequent laser chain, the presented device avoids parasitic pulses and is therefore the preferable alternative for high-contrast applications. Moreover the device is easily scalable for large beam diameters and its spectral reflectivity can be adjusted by an appropriate mirror coating to be well suited for ultra-short laser pulses. PMID:23037123

  19. Accurate verification of the conserved-vector-current and standard-model predictions

    SciTech Connect

    Sirlin, A.; Zucchini, R.

    1986-10-20

    An approximate analytic calculation of O(Z..cap alpha../sup 2/) corrections to Fermi decays is presented. When the analysis of Koslowsky et al. is modified to take into account the new results, it is found that each of the eight accurately studied scrFt values differs from the average by approx. <1sigma, thus significantly improving the comparison of experiments with conserved-vector-current predictions. The new scrFt values are lower than before, which also brings experiments into very good agreement with the three-generation standard model, at the level of its quantum corrections.

  20. Accurate estimation of the RMS emittance from single current amplifier data

    SciTech Connect

    Stockli, Martin P.; Welton, R.F.; Keller, R.; Letchford, A.P.; Thomae, R.W.; Thomason, J.W.G.

    2002-05-31

    This paper presents the SCUBEEx rms emittance analysis, a self-consistent, unbiased elliptical exclusion method, which combines traditional data-reduction methods with statistical methods to obtain accurate estimates for the rms emittance. Rather than considering individual data, the method tracks the average current density outside a well-selected, variable boundary to separate the measured beam halo from the background. The average outside current density is assumed to be part of a uniform background and not part of the particle beam. Therefore the average outside current is subtracted from the data before evaluating the rms emittance within the boundary. As the boundary area is increased, the average outside current and the inside rms emittance form plateaus when all data containing part of the particle beam are inside the boundary. These plateaus mark the smallest acceptable exclusion boundary and provide unbiased estimates for the average background and the rms emittance. Small, trendless variations within the plateaus allow for determining the uncertainties of the estimates caused by variations of the measured background outside the smallest acceptable exclusion boundary. The robustness of the method is established with complementary variations of the exclusion boundary. This paper presents a detailed comparison between traditional data reduction methods and SCUBEEx by analyzing two complementary sets of emittance data obtained with a Lawrence Berkeley National Laboratory and an ISIS H{sup -} ion source.

  1. Small pores in soils: Is the physico-chemical environment accurately reflected in biogeochemical models ?

    NASA Astrophysics Data System (ADS)

    Weber, Tobias K. D.; Riedel, Thomas

    2015-04-01

    Free water is a prerequesite to chemical reactions and biological activity in earth's upper crust essential to life. The void volume between the solid compounds provides space for water, air, and organisms that thrive on the consumption of minerals and organic matter thereby regulating soil carbon turnover. However, not all water in the pore space in soils and sediments is in its liquid state. This is a result of the adhesive forces which reduce the water activity in small pores and charged mineral surfaces. This water has a lower tendency to react chemically in solution as this additional binding energy lowers its activity. In this work, we estimated the amount of soil pore water that is thermodynamically different from a simple aqueous solution. The quantity of soil pore water with properties different to liquid water was found to systematically increase with increasing clay content. The significance of this is that the grain size and surface area apparently affects the thermodynamic state of water. This implies that current methods to determine the amount of water content, traditionally determined from bulk density or gravimetric water content after drying at 105°C overestimates the amount of free water in a soil especially at higher clay content. Our findings have consequences for biogeochemical processes in soils, e.g. nutrients may be contained in water which is not free which could enhance preservation. From water activity measurements on a set of various soils with 0 to 100 wt-% clay, we can show that 5 to 130 mg H2O per g of soil can generally be considered as unsuitable for microbial respiration. These results may therefore provide a unifying explanation for the grain size dependency of organic matter preservation in sedimentary environments and call for a revised view on the biogeochemical environment in soils and sediments. This could allow a different type of process oriented modelling.

  2. How Should Risk-Based Regulation Reflect Current Public Opinion?

    PubMed

    Pollock, Christopher John

    2016-08-01

    Risk-based regulation of novel agricultural products with public choice manifest via traceability and labelling is a more effective approach than the use of regulatory processes to reflect public concerns, which may not always be supported by evidence. PMID:27266813

  3. High definition i-SCAN endoscopy with water immersion technique accurately reflects histological severity of celiac disease

    PubMed Central

    Iacucci, Marietta; Poon, Tiffany; Gui, X. Sean; Subrata, Ghosh

    2016-01-01

    Background and aims: Severe villous atrophy can be revealed with conventional white light endoscopy (WLE), however, milder grades or patchy villous atrophy are more difficult to detect. Novel endoscopic techniques such as high definition i-SCAN endoscopy with the water immersion technique (i-SCAN-HDWI) may provide the ability to visualize duodenal villi more accurately. We aimed to determine the performance of i-SCAN-HDWI in evaluating the severity of histological damage in the duodenum of patients with celiac disease. Patients and methods: A retrospective cohort study was performed in a single tertiary academic endoscopic center. We studied 58 patients (46 women; median age 36.5 years, range 18 – 72 years) with positive anti-TTG IgA antibody. The villous pattern of the second part of the duodenum was assessed by WLE and i-SCAN-HDWI. The endoscopic grades in both techniques were correlated using Marsh histologic grades by Spearman correlation coefficient. The diagnostic accuracy of i-SCAN-HDWI for detection of patchy or complete atrophy of the villi was evaluated. Results: A significant correlation was demonstrated between endoscopic grade using i-SCAN-HDWI and Marsh histologic grade (r = 0.732; P < 0.00001). The correlation between WLE grade and Marsh histologic grade was inferior to i-SCAN-HDWI (r = 0.31; P = 0.01). The sensitivity of i-SCAN-HDWI was 96 % (95 %CI: 85 – 99 %) and the specificity was 63 % (95 %CI: 26 – 90 %) in diagnosing abnormal biopsy consistent with celiac disease. Conclusion: i-SCAN-HDWI endoscopy can reflect the histological severity of celiac disease more accurately than conventional WLE alone. This novel endoscopic imaging can improve the diagnostic yield of duodenal biopsies in celiac patients, especially for those with a patchy distribution of villous damage. PMID:27227112

  4. Josephson Current and Multiple Andreev Reflections in Graphene SNS Junctions

    NASA Astrophysics Data System (ADS)

    Skachko, Ivan; Du, Xu; Andrei, Eva Y.

    2008-03-01

    The Josephson Effect and Superconducting Proximity Effect were observed in Superconductor-Graphene-Superconductor (SGS) Josephson junctions with coherence lengths comparable to the distance between the superconducting leads. By comparing the measured temperature and gate dependence of the supercurrent and the proximity induced sub-gap features (multiple Andreev reflections) to theoretical predictions, we find that the diffusive junction model yields close quantitative agreement with the results. This is consistent with the fact that the measured mean free paths in these junctions, 10 ˜ 30 nm, are significantly shorter than the lead separation. We show that all SGS devices reported so far fall in the diffusive junction category.

  5. 40 CFR 450.21 - Effluent limitations reflecting the best practicable technology currently available (BPT).

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... limitations reflecting the best practicable technology currently available (BPT). Except as provided in 40 CFR... whenever any clearing, grading, excavating or other earth disturbing activities have permanently ceased...

  6. Assessment of a sponge layer as a non-reflective boundary treatment with highly accurate gust–airfoil interaction results

    NASA Astrophysics Data System (ADS)

    Crivellini, A.

    2016-02-01

    This paper deals with the numerical performance of a sponge layer as a non-reflective boundary condition. This technique is well known and widely adopted, but only recently have the reasons for a sponge failure been recognised, in analysis by Mani. For multidimensional problems, the ineffectiveness of the method is due to the self-reflections of the sponge occurring when it interacts with an oblique acoustic wave. Based on his theoretical investigations, Mani gives some useful guidelines for implementing effective sponge layers. However, in our opinion, some practical indications are still missing from the current literature. Here, an extensive numerical study of the performance of this technique is presented. Moreover, we analyse a reduced sponge implementation characterised by undamped partial differential equations for the velocity components. The main aim of this paper relies on the determination of the minimal width of the layer, as well as of the corresponding strength, required to obtain a reflection error of no more than a few per cent of that observed when solving the same problem on the same grid, but without employing the sponge layer term. For this purpose, a test case of computational aeroacoustics, the single airfoil gust response problem, has been addressed in several configurations. As a direct consequence of our investigation, we present a well documented and highly validated reference solution for the far-field acoustic intensity, a result that is not well established in the literature. Lastly, the proof of the accuracy of an algorithm for coupling sub-domains solved by the linear and non-liner Euler governing equations is given. This result is here exploited to adopt a linear-based sponge layer even in a non-linear computation.

  7. Josephson current and multiple Andreev reflections in graphene SNS junctions

    NASA Astrophysics Data System (ADS)

    Du, Xu; Skachko, Ivan; Andrei, Eva Y.

    2008-05-01

    The Josephson effect and superconducting proximity effect were observed in superconductor-graphene-superconductor (SGS) Josephson junctions with coherence lengths comparable to the distance between the superconducting leads. By comparing the measured gate dependence of the proximity induced subgap features (multiple Andreev reflections) and of the supercurrent to theoretical predictions, we find that the diffusive junction model yields close quantitative agreement with the results. By contrast, predictions of the ballistic SGS model are inconsistent with the data. We show that all SGS devices reported so far, our own as well as those of other groups, fall in the diffusive junction category. This is attributed to substrate induced potential fluctuations due to trapped charges and to the invasiveness of the metallic leads.

  8. Reflections on Current Issues in Science and Technology.

    ERIC Educational Resources Information Center

    Harrison, Anna J.

    1982-01-01

    Presented are the personal perceptions of Anna J. Harrison, president-elect of the American Association for the Advancement of Science, on current issues in science and technology as they relate to the integrity of science, impact on society, society's impact, the environment, public decisions, and human resources. (DC)

  9. Reflectance and substrate currents of dielectric layers under vacuum ultraviolet irradiation

    SciTech Connect

    Sinha, H.; Straight, D. B.; Lauer, J. L.; Fuller, N. C.; Engelmann, S. U.; Zhang, Y.; Antonelli, G. A.; Severson, M.; Nishi, Y.; Shohet, J. L.

    2010-11-15

    The reflectance of low-k porous organosilicate glass (SiCOH) as a function of photon energy under synchrotron vacuum ultraviolet (VUV) radiation was measured using a nickel mesh reflectometer. The authors found that during VUV irradiation, the reflectance of SiCOH and the substrate current were inversely correlated. Thus, reflectance can be inferred from substrate current measurements and vice versa. The authors conclude that reflectance or substrate current measurements can determine the photon energies that are absorbed and, therefore, cause dielectric damage during processing. Thus, reducing the flux of deleterious photon energies in processing systems can minimize dielectric damage.

  10. Moving Forward from the Past: Early Writings and Current Reflections of Middle School Founders.

    ERIC Educational Resources Information Center

    David, Robert, Ed.

    Twenty-three articles by five educators who wrote in the 1960's and 1970's about the then new concept of the middle school are gathered, along with current essays reflecting on the insight these papers provide for current middle-school concerns. In the first section, C. Kenneth McEwin reflects on the current impact of these writings of William M.…

  11. Extracting accurate strain measurements in bone mechanics: A critical review of current methods.

    PubMed

    Grassi, Lorenzo; Isaksson, Hanna

    2015-10-01

    Osteoporosis related fractures are a social burden that advocates for more accurate fracture prediction methods. Mechanistic methods, e.g. finite element models, have been proposed as a tool to better predict bone mechanical behaviour and strength. However, there is little consensus about the optimal constitutive law to describe bone as a material. Extracting reliable and relevant strain data from experimental tests is of fundamental importance to better understand bone mechanical properties, and to validate numerical models. Several techniques have been used to measure strain in experimental mechanics, with substantial differences in terms of accuracy, precision, time- and length-scale. Each technique presents upsides and downsides that must be carefully evaluated when designing the experiment. Moreover, additional complexities are often encountered when applying such strain measurement techniques to bone, due to its complex composite structure. This review of literature examined the four most commonly adopted methods for strain measurements (strain gauges, fibre Bragg grating sensors, digital image correlation, and digital volume correlation), with a focus on studies with bone as a substrate material, at the organ and tissue level. For each of them the working principles, a summary of the main applications to bone mechanics at the organ- and tissue-level, and a list of pros and cons are provided. PMID:26099201

  12. Are current atomistic force fields accurate enough to study proteins in crowded environments?

    PubMed

    Petrov, Drazen; Zagrovic, Bojan

    2014-05-01

    The high concentration of macromolecules in the crowded cellular interior influences different thermodynamic and kinetic properties of proteins, including their structural stabilities, intermolecular binding affinities and enzymatic rates. Moreover, various structural biology methods, such as NMR or different spectroscopies, typically involve samples with relatively high protein concentration. Due to large sampling requirements, however, the accuracy of classical molecular dynamics (MD) simulations in capturing protein behavior at high concentration still remains largely untested. Here, we use explicit-solvent MD simulations and a total of 6.4 µs of simulated time to study wild-type (folded) and oxidatively damaged (unfolded) forms of villin headpiece at 6 mM and 9.2 mM protein concentration. We first perform an exhaustive set of simulations with multiple protein molecules in the simulation box using GROMOS 45a3 and 54a7 force fields together with different types of electrostatics treatment and solution ionic strengths. Surprisingly, the two villin headpiece variants exhibit similar aggregation behavior, despite the fact that their estimated aggregation propensities markedly differ. Importantly, regardless of the simulation protocol applied, wild-type villin headpiece consistently aggregates even under conditions at which it is experimentally known to be soluble. We demonstrate that aggregation is accompanied by a large decrease in the total potential energy, with not only hydrophobic, but also polar residues and backbone contributing substantially. The same effect is directly observed for two other major atomistic force fields (AMBER99SB-ILDN and CHARMM22-CMAP) as well as indirectly shown for additional two (AMBER94, OPLS-AAL), and is possibly due to a general overestimation of the potential energy of protein-protein interactions at the expense of water-water and water-protein interactions. Overall, our results suggest that current MD force fields may distort the

  13. Are Current Atomistic Force Fields Accurate Enough to Study Proteins in Crowded Environments?

    PubMed Central

    Petrov, Drazen; Zagrovic, Bojan

    2014-01-01

    The high concentration of macromolecules in the crowded cellular interior influences different thermodynamic and kinetic properties of proteins, including their structural stabilities, intermolecular binding affinities and enzymatic rates. Moreover, various structural biology methods, such as NMR or different spectroscopies, typically involve samples with relatively high protein concentration. Due to large sampling requirements, however, the accuracy of classical molecular dynamics (MD) simulations in capturing protein behavior at high concentration still remains largely untested. Here, we use explicit-solvent MD simulations and a total of 6.4 µs of simulated time to study wild-type (folded) and oxidatively damaged (unfolded) forms of villin headpiece at 6 mM and 9.2 mM protein concentration. We first perform an exhaustive set of simulations with multiple protein molecules in the simulation box using GROMOS 45a3 and 54a7 force fields together with different types of electrostatics treatment and solution ionic strengths. Surprisingly, the two villin headpiece variants exhibit similar aggregation behavior, despite the fact that their estimated aggregation propensities markedly differ. Importantly, regardless of the simulation protocol applied, wild-type villin headpiece consistently aggregates even under conditions at which it is experimentally known to be soluble. We demonstrate that aggregation is accompanied by a large decrease in the total potential energy, with not only hydrophobic, but also polar residues and backbone contributing substantially. The same effect is directly observed for two other major atomistic force fields (AMBER99SB-ILDN and CHARMM22-CMAP) as well as indirectly shown for additional two (AMBER94, OPLS-AAL), and is possibly due to a general overestimation of the potential energy of protein-protein interactions at the expense of water-water and water-protein interactions. Overall, our results suggest that current MD force fields may distort the

  14. Reflections on current and future applications of multiangle imaging to aerosol and cloud remote sensing

    NASA Astrophysics Data System (ADS)

    Diner, David

    2010-05-01

    The Multi-angle Imaging SpectroRadiometer (MISR) instrument has been collecting global Earth data from NASA's Terra satellite since February 2000. With its 9 along-track view angles, 4 spectral bands, intrinsic spatial resolution of 275 m, and stable radiometric and geometric calibration, no instrument that combines MISR's attributes has previously flown in space, nor is there is a similar capability currently available on any other satellite platform. Multiangle imaging offers several tools for remote sensing of aerosol and cloud properties, including bidirectional reflectance and scattering measurements, stereoscopic pattern matching, time lapse sequencing, and potentially, optical tomography. Current data products from MISR employ several of these techniques. Observations of the intensity of scattered light as a function of view angle and wavelength provide accurate measures of aerosol optical depths (AOD) over land, including bright desert and urban source regions. Partitioning of AOD according to retrieved particle classification and incorporation of height information improves the relationship between AOD and surface PM2.5 (fine particulate matter, a regulated air pollutant), constituting an important step toward a satellite-based particulate pollution monitoring system. Stereoscopic cloud-top heights provide a unique metric for detecting interannual variability of clouds and exceptionally high quality and sensitivity for detection and height retrieval for low-level clouds. Using the several-minute time interval between camera views, MISR has enabled a pole-to-pole, height-resolved atmospheric wind measurement system. Stereo imagery also makes possible global measurement of the injection heights and advection speeds of smoke plumes, volcanic plumes, and dust clouds, for which a large database is now available. To build upon what has been learned during the first decade of MISR observations, we are evaluating algorithm updates that not only refine retrieval

  15. 40 CFR 450.21 - Effluent limitations reflecting the best practicable technology currently available (BPT).

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... limitations reflecting the best practicable technology currently available (BPT). Except as provided in 40 CFR... the best practicable control technology currently available (BPT). (a) Erosion and sediment controls. Design, install and maintain effective erosion controls and sediment controls to minimize the...

  16. 40 CFR 450.21 - Effluent limitations reflecting the best practicable technology currently available (BPT).

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... limitations reflecting the best practicable technology currently available (BPT). Except as provided in 40 CFR... the best practicable control technology currently available (BPT). (a) Erosion and sediment controls. Design, install and maintain effective erosion controls and sediment controls to minimize the...

  17. Alfven Wave Reflection Model of Field-Aligned Currents at Mercury

    NASA Technical Reports Server (NTRS)

    Lyatsky, Wladislaw; Khazanov, George V.; Slavin, James

    2010-01-01

    An Alfven Wave Reflection (AWR) model is proposed that provides closure for strong field-aligned currents (FACs) driven by the magnetopause reconnection in the magnetospheres of planets having no significant ionospheric and surface electrical conductance. The model is based on properties of the Alfven waves, generated at high altitudes and reflected from the low-conductivity surface of the planet. When magnetospheric convection is very slow, the incident and reflected Alfven waves propagate along approximately the same path. In this case, the net field-aligned currents will be small. However, as the convection speed increases. the reflected wave is displaced relatively to the incident wave so that the incident and reflected waves no longer compensate each other. In this case, the net field-aligned current may be large despite the lack of significant ionospheric and surface conductivity. Our estimate shows that for typical solar wind conditions at Mercury, the magnitude of Region 1-type FACs in Mercury's magnetosphere may reach hundreds of kilo-Amperes. This AWR model of field-aligned currents may provide a solution to the long-standing problem of the closure of FACs in the Mercury's magnetosphere. c2009 Elsevier Inc. All rights reserved.

  18. Activity ratios of ribulose-1,5-bisphosphate carboxylase accurately reflect carbamylation ratios. [Phaseolus vulgaris, Spinacla oleracea

    SciTech Connect

    Butz, N.D.; Sharkey, T.D. )

    1989-03-01

    Activity ratios and carbamylation ratios of ribulose-1,5-bisphosphate carboxylase (RuBPCase) were determined for leaves of Phaseolus vulgaris and Spinacia oleracea exposed to a variety of partial pressures of CO{sub 2} and O{sub 2} and photon flux densities (PFD). It was found that activity ratios accurately predicted carbamylation ratios except in extracts from leaves held in low PFD. In particular, it was confirmed that the loss of FuBPCase activity in low partial pressure of O{sub 2} and high PFD results from reduced carbamylation. Activity ratios of RuBPCase were lower than carbamylation ratios for Phaseolus leaves sampled in low PFD, presumably because of the presence of 2-carboxyarabinitol 1-phosphate. Spinacia leaves sampled in darkness also exhibited lower activity ratios than carbamylation ratios indicating that this species may also have an RuBPCase inhibitor even though carboxyarabinitol 1-phosphate has not been detected in this species in the past.

  19. A new method of accurate broken rotor bar diagnosis based on modulation signal bispectrum analysis of motor current signals

    NASA Astrophysics Data System (ADS)

    Gu, F.; Wang, T.; Alwodai, A.; Tian, X.; Shao, Y.; Ball, A. D.

    2015-01-01

    Motor current signature analysis (MCSA) has been an effective way of monitoring electrical machines for many years. However, inadequate accuracy in diagnosing incipient broken rotor bars (BRB) has motivated many studies into improving this method. In this paper a modulation signal bispectrum (MSB) analysis is applied to motor currents from different broken bar cases and a new MSB based sideband estimator (MSB-SE) and sideband amplitude estimator are introduced for obtaining the amplitude at (1 ± 2 s)fs (s is the rotor slip and fs is the fundamental supply frequency) with high accuracy. As the MSB-SE has a good performance of noise suppression, the new estimator produces more accurate results in predicting the number of BRB, compared with conventional power spectrum analysis. Moreover, the paper has also developed an improved model for motor current signals under rotor fault conditions and an effective method to decouple the BRB current which interferes with that of speed oscillations associated with BRB. These provide theoretical supports for the new estimators and clarify the issues in using conventional bispectrum analysis.

  20. Extent to Which Teacher Beliefs and Practices Reflect Current Research on Historical Thinking and Understanding

    ERIC Educational Resources Information Center

    Carroll, Erich C.

    2013-01-01

    This study examined the extent to which teacher beliefs and practices at the high school level reflect current research on historical thinking and understanding. The topic is significant as teachers are a crucial variable in a child's education and evidence over the years has revealed that students have long struggled in developing conceptual…

  1. Do inverse ecosystem models accurately reconstruct plankton trophic flows? Comparing two solution methods using field data from the California Current

    NASA Astrophysics Data System (ADS)

    Stukel, Michael R.; Landry, Michael R.; Ohman, Mark D.; Goericke, Ralf; Samo, Ty; Benitez-Nelson, Claudia R.

    2012-03-01

    Despite the increasing use of linear inverse modeling techniques to elucidate fluxes in undersampled marine ecosystems, the accuracy with which they estimate food web flows has not been resolved. New Markov Chain Monte Carlo (MCMC) solution methods have also called into question the biases of the commonly used L2 minimum norm (L 2MN) solution technique. Here, we test the abilities of MCMC and L 2MN methods to recover field-measured ecosystem rates that are sequentially excluded from the model input. For data, we use experimental measurements from process cruises of the California Current Ecosystem (CCE-LTER) Program that include rate estimates of phytoplankton and bacterial production, micro- and mesozooplankton grazing, and carbon export from eight study sites varying from rich coastal upwelling to offshore oligotrophic conditions. Both the MCMC and L 2MN methods predicted well-constrained rates of protozoan and mesozooplankton grazing with reasonable accuracy, but the MCMC method overestimated primary production. The MCMC method more accurately predicted the poorly constrained rate of vertical carbon export than the L 2MN method, which consistently overestimated export. Results involving DOC and bacterial production were equivocal. Overall, when primary production is provided as model input, the MCMC method gives a robust depiction of ecosystem processes. Uncertainty in inverse ecosystem models is large and arises primarily from solution under-determinacy. We thus suggest that experimental programs focusing on food web fluxes expand the range of experimental measurements to include the nature and fate of detrital pools, which play large roles in the model.

  2. Do current cost-effectiveness analyses reflect the full value of childhood vaccination in Europe?

    PubMed Central

    Brüggenjürgen, Bernd; Lorrot, Mathie; Sheppard, Fiona R; Rémy, Vanessa

    2014-01-01

    Economic evaluation of vaccination programs can be challenging and does not always fully capture the benefits provided. Reasons for this include the difficulties incurred in accurately capturing the health and economic impact of infectious diseases and how different diseases may interact with each other. Rotavirus infection, for example, peaks at a similar time than other infectious diseases, such as RSV and influenza, which can cause hospital overcrowding and disruption, and may pose a risk to more vulnerable children due to limited availability of isolation facilities. Another challenge, specific to evaluating childhood vaccination, is that QoL cannot be accurately measured in children due to a lack of validated instruments. Childhood diseases also incur a care giver burden, due to the need for parents to take time off work, and this is important to consider. Finally, for diseases such as RVGE, cost-effectiveness analyses in which longer time horizons are considered may not reflect the short-term benefits of vaccination. Further quantification of the economic impact of childhood diseases is thus required to fully highlight the true benefits of childhood vaccination that may be realized. Herein we explore the limitations of existing economic evaluations for childhood vaccination, and how economic analyses could be better adapted in future. PMID:25424934

  3. A fast and accurate calculation in three dimensions of the charge and current induced on all the electrodes of wire chambers

    SciTech Connect

    Bellazzini, R.; Brez, A.; Massai, M.M.; Torquati, M.R.

    1985-02-01

    A fast and accurate algorithm to calculate the charge and current induced on all the electrodes of wire chambers (MWPC, 'pad chambers', TPC. . . .) is presented. The algorithm is completely three dimensional so that it is possible to calculate the induced charge on anode wires and cathode strips or 'pads' regardless of their orientation in space.

  4. CLARREO Cornerstone of the Earth Observing System: Measuring Decadal Change Through Accurate Emitted Infrared and Reflected Solar Spectra and Radio Occultation

    NASA Technical Reports Server (NTRS)

    Sandford, Stephen P.

    2010-01-01

    The Climate Absolute Radiance and Refractivity Observatory (CLARREO) is one of four Tier 1 missions recommended by the recent NRC Decadal Survey report on Earth Science and Applications from Space (NRC, 2007). The CLARREO mission addresses the need to provide accurate, broadly acknowledged climate records that are used to enable validated long-term climate projections that become the foundation for informed decisions on mitigation and adaptation policies that address the effects of climate change on society. The CLARREO mission accomplishes this critical objective through rigorous SI traceable decadal change observations that are sensitive to many of the key uncertainties in climate radiative forcings, responses, and feedbacks that in turn drive uncertainty in current climate model projections. These same uncertainties also lead to uncertainty in attribution of climate change to anthropogenic forcing. For the first time CLARREO will make highly accurate, global, SI-traceable decadal change observations sensitive to the most critical, but least understood, climate forcings, responses, and feedbacks. The CLARREO breakthrough is to achieve the required levels of accuracy and traceability to SI standards for a set of observations sensitive to a wide range of key decadal change variables. The required accuracy levels are determined so that climate trend signals can be detected against a background of naturally occurring variability. Climate system natural variability therefore determines what level of accuracy is overkill, and what level is critical to obtain. In this sense, the CLARREO mission requirements are considered optimal from a science value perspective. The accuracy for decadal change traceability to SI standards includes uncertainties associated with instrument calibration, satellite orbit sampling, and analysis methods. Unlike most space missions, the CLARREO requirements are driven not by the instantaneous accuracy of the measurements, but by accuracy in

  5. An accurate online calibration system based on combined clamp-shape coil for high voltage electronic current transformers.

    PubMed

    Li, Zhen-hua; Li, Hong-bin; Zhang, Zhi

    2013-07-01

    Electronic transformers are widely used in power systems because of their wide bandwidth and good transient performance. However, as an emerging technology, the failure rate of electronic transformers is higher than that of traditional transformers. As a result, the calibration period needs to be shortened. Traditional calibration methods require the power of transmission line be cut off, which results in complicated operation and power off loss. This paper proposes an online calibration system which can calibrate electronic current transformers without power off. In this work, the high accuracy standard current transformer and online operation method are the key techniques. Based on the clamp-shape iron-core coil and clamp-shape air-core coil, a combined clamp-shape coil is designed as the standard current transformer. By analyzing the output characteristics of the two coils, the combined clamp-shape coil can achieve verification of the accuracy. So the accuracy of the online calibration system can be guaranteed. Moreover, by employing the earth potential working method and using two insulating rods to connect the combined clamp-shape coil to the high voltage bus, the operation becomes simple and safe. Tests in China National Center for High Voltage Measurement and field experiments show that the proposed system has a high accuracy of up to 0.05 class. PMID:23902112

  6. An accurate online calibration system based on combined clamp-shape coil for high voltage electronic current transformers

    SciTech Connect

    Li, Zhen-hua; Li, Hong-bin; Zhang, Zhi

    2013-07-15

    Electronic transformers are widely used in power systems because of their wide bandwidth and good transient performance. However, as an emerging technology, the failure rate of electronic transformers is higher than that of traditional transformers. As a result, the calibration period needs to be shortened. Traditional calibration methods require the power of transmission line be cut off, which results in complicated operation and power off loss. This paper proposes an online calibration system which can calibrate electronic current transformers without power off. In this work, the high accuracy standard current transformer and online operation method are the key techniques. Based on the clamp-shape iron-core coil and clamp-shape air-core coil, a combined clamp-shape coil is designed as the standard current transformer. By analyzing the output characteristics of the two coils, the combined clamp-shape coil can achieve verification of the accuracy. So the accuracy of the online calibration system can be guaranteed. Moreover, by employing the earth potential working method and using two insulating rods to connect the combined clamp-shape coil to the high voltage bus, the operation becomes simple and safe. Tests in China National Center for High Voltage Measurement and field experiments show that the proposed system has a high accuracy of up to 0.05 class.

  7. A Study to Test the Feasibility of Determining Whether Classified Want Ads in Daily Newspapers Are an Accurate Reflection of Local Labor Markets and of Significant Use to Employers and Job Seekers. Final Report.

    ERIC Educational Resources Information Center

    Olympus Research Corp., Salt Lake City, UT.

    The report summarizes findings of a detailed study to test the feasibility of determining whether want ads in daily newspapers are (1) an accurate reflection of local labor markets and (2) of significant use to employers and job seekers. The study found that want ads are a limited source of information about local labor markets. They are of some…

  8. How accurately can current, planned and proposed InSAR missions measure slow, long-wavelength tectonic strain? (Invited)

    NASA Astrophysics Data System (ADS)

    Wright, T. J.; Garthwaite, M.; Jung, H.; Shepherd, A.

    2010-12-01

    Since the launch of ERS-1 in 1991, InSAR has been widely used to measure large deformation events such as earthquakes or volcanic eruptions. In the last decade, small strains accumulating around locked crustal faults and dormant volcanic edifices have also been measured, in certain favourable conditions. In this presentation, we discuss the accuracy of current, planned and proposed InSAR missions. We quantify the main contributions to the error budget of a single interferogram at different spatial scales: atmospheric and orbital errors dominate at long wavelengths (tens of kilometres), and errors from system noise and surface incoherence at short spatial scales (tens of metres). We show that the optimum method for combining multiple interferograms to measure the average line-of-sight (LOS) deformation rate is via a weighted linear inversion of a connected network of short-interval interferograms. The LOS accuracy is strongly dependent on the mission length and satellite revisit time, as well as the spatial length scale. For example, to obtain an LOS accuracy of 1 mm/yr over 100 km requires 5 years of observation with a 13-day repeat, or 7 years for a 35-day repeat. We assess the ability of current (ERS/Envisat), planned (Sentinel-1), and proposed (SuperSAR, DesDYNI) satellite missions to measure long wavelength tectonic strain by estimating the proportion of global straining areas (as defined by the Global Strain Rate Map) where the strain rates are higher than the measurement error. The results highlight the importance of obtaining measurements in three dimensions in order to monitor all actively deforming regions. Of the planned/proposed missions, only SuperSAR (submitted to ESA’s Earth Explorer 8 call) has the ability to achieve 1 mm/yr accuracy over 100 km in all three dimensions after 5 years of observation. This is sufficient to map strain accumulating around faults that are responsible for 95% of damaging onshore earthquakes.

  9. Reflections in computer modeling of rooms: Current approaches and possible extensions

    NASA Astrophysics Data System (ADS)

    Svensson, U. Peter

    2005-09-01

    Computer modeling of rooms is most commonly done by some calculation technique that is based on decomposing the sound field into separate reflection components. In a first step, a list of possible reflection paths is found and in a second step, an impulse response is constructed from the list of reflections. Alternatively, the list of reflections is used for generating a simpler echogram, the energy decay as function of time. A number of geometrical acoustics-based methods can handle specular reflections, diffuse reflections, edge diffraction, curved surfaces, and locally/non-locally reacting surfaces to various degrees. This presentation gives an overview of how reflections are handled in the image source method and variants of the ray-tracing methods, which are dominating today in commercial software, as well as in the radiosity method and edge diffraction methods. The use of the recently standardized scattering and diffusion coefficients of surfaces is discussed. Possibilities for combining edge diffraction, surface scattering, and impedance boundaries are demonstrated for an example surface. Finally, the number of reflection paths becomes prohibitively high when all such combinations are included as demonstrated for a simple concert hall model. [Work supported by the Acoustic Research Centre through NFR, Norway.

  10. Measuring Physical Inactivity: Do Current Measures Provide an Accurate View of “Sedentary” Video Game Time?

    PubMed Central

    Fullerton, Simon; Taylor, Anne W.; Dal Grande, Eleonora; Berry, Narelle

    2014-01-01

    Background. Measures of screen time are often used to assess sedentary behaviour. Participation in activity-based video games (exergames) can contribute to estimates of screen time, as current practices of measuring it do not consider the growing evidence that playing exergames can provide light to moderate levels of physical activity. This study aimed to determine what proportion of time spent playing video games was actually spent playing exergames. Methods. Data were collected via a cross-sectional telephone survey in South Australia. Participants aged 18 years and above (n = 2026) were asked about their video game habits, as well as demographic and socioeconomic factors. In cases where children were in the household, the video game habits of a randomly selected child were also questioned. Results. Overall, 31.3% of adults and 79.9% of children spend at least some time playing video games. Of these, 24.1% of adults and 42.1% of children play exergames, with these types of games accounting for a third of all time that adults spend playing video games and nearly 20% of children's video game time. Conclusions. A substantial proportion of time that would usually be classified as “sedentary” may actually be spent participating in light to moderate physical activity. PMID:25002974

  11. Are Currently Available Wearable Devices for Activity Tracking and Heart Rate Monitoring Accurate, Precise, and Medically Beneficial?

    PubMed Central

    El-Amrawy, Fatema

    2015-01-01

    Objectives The new wave of wireless technologies, fitness trackers, and body sensor devices can have great impact on healthcare systems and the quality of life. However, there have not been enough studies to prove the accuracy and precision of these trackers. The objective of this study was to evaluate the accuracy, precision, and overall performance of seventeen wearable devices currently available compared with direct observation of step counts and heart rate monitoring. Methods Each participant in this study used three accelerometers at a time, running the three corresponding applications of each tracker on an Android or iOS device simultaneously. Each participant was instructed to walk 200, 500, and 1,000 steps. Each set was repeated 40 times. Data was recorded after each trial, and the mean step count, standard deviation, accuracy, and precision were estimated for each tracker. Heart rate was measured by all trackers (if applicable), which support heart rate monitoring, and compared to a positive control, the Onyx Vantage 9590 professional clinical pulse oximeter. Results The accuracy of the tested products ranged between 79.8% and 99.1%, while the coefficient of variation (precision) ranged between 4% and 17.5%. MisFit Shine showed the highest accuracy and precision (along with Qualcomm Toq), while Samsung Gear 2 showed the lowest accuracy, and Jawbone UP showed the lowest precision. However, Xiaomi Mi band showed the best package compared to its price. Conclusions The accuracy and precision of the selected fitness trackers are reasonable and can indicate the average level of activity and thus average energy expenditure. PMID:26618039

  12. Systematic errors inherent in the current modeling of the reflected downward flux term used by remote sensing models.

    PubMed

    Turner, David S

    2004-04-10

    An underlying assumption of satellite data assimilation systems is that the radiative transfer model used to simulate observed satellite radiances has no errors. For practical reasons a fast-forward radiative transfer model is used instead of a highly accurate line-by-line model. The fast model usually replaces the spectral integration of spectral quantities with their monochromatic equivalents, and the errors due to these approximations are assumed to be negligible. The reflected downward flux term contains many approximations of this nature, which are shown to introduce systematic errors. In addition, many fast-forward radiative transfer models simulate the downward flux as the downward radiance along a path defined by the secant of the mean emergent angle, the diffusivity factor. The diffusivity factor is commonly set to 1.66 or to the secant of the satellite zenith angle. Neither case takes into account that the diffusivity factor varies with optical depth, which introduces further errors. I review the two most commonly used methods for simulating reflected downward flux by fast-forward radiative transfer models and point out their inadequacies and limitations. An alternate method of simulating the reflected downward flux is proposed. This method transforms the surface-to-satellite transmittance profile to a transmittance profile suitable for simulating the reflected downward flux by raising the former transmittance to the power of kappa, where kappa itself is a function of channel, surface pressure, and satellite zenith angle. It is demonstrated that this method reduces the fast-forward model error for low to moderate reflectivities. PMID:15098841

  13. Analytical determination of the reflection coefficient by the evanescent modes model during the wave-current-horizontal plate interaction

    NASA Astrophysics Data System (ADS)

    Errifaiy, Meriem; Naasse, Smail; Chahine, Chakib

    2016-07-01

    Our work presents an analytical study of the determination of the reflection coefficient during the interaction between the regular wave current and a horizontal plate. This study was done using the linearized potential flow theory with the evanescent modes model, while searching for complex solutions to the dispersion equation that are neither real pure nor imaginary pure. To validate the established model, it has been confronted with the experimental results of V. Rey and J. Touboul, in a first phase, and then compared to those of the numerical study by H.-X. Lin et al. Then, this model was used to study the effect of current on the reflection coefficient. xml:lang="fr"

  14. Reflection of Transverse Waves in a Structure "Dielectric-Piezoelectric Semiconductor with Current"

    NASA Astrophysics Data System (ADS)

    Lyamshev, L. M.; Shevyakhov, N. S.

    2000-05-01

    Reflection of a plane monochromatic transverse wave by the boundary of the acoustic contact of a dielectric with a hexagonal piezoelectric semiconductor in the presence of a longitudinal charge drift is treated in the small-signal approximation within the framework of the hydrodynamic description of a charge carrier plasma. A procedure of selecting the branches with allowance for the conversion of the quasi-acoustic mode (a refracted transverse wave) into plasma-acoustic disturbances, both in-leaking at the boundary or out-leaking from it, is proposed for the determination of the solution under the conditions of a supersonic drift and “overcritical” angles of incidence. Beyond the restrictions of White’s theory of ultrasonic wave propagation in piezoelectric semiconductors, it is demonstrated that this technique removes the defects of the solutions obtained earlier in the form of discontinuities in angular dependences of the modulus of the reflection coefficient of a transverse wave in the vicinity of the “critical” angle of incidence and leads to a solution that does not contain a resonance singularity of a polar type.

  15. Immediate-early gene transcriptional activation in hippocampus CA1 and CA3 does not accurately reflect rapid, pattern completion-based retrieval of context memory

    PubMed Central

    Pevzner, Aleksandr

    2015-01-01

    No studies to date have examined whether immediate-early gene (IEG) activation is driven by context memory recall. To address this question, we utilized the context preexposure facilitation effect (CPFE) paradigm. In CPFE, animals acquire contextual fear conditioning through hippocampus-dependent rapid retrieval of a previously formed contextual representation. Despite differences in behavior, we did not find any difference in CA1 or CA3 IEG activity associated with this rapid recall phase when comparing context preexposed and non-pre-exposed groups. These findings indicate that IEG activation in CA1 and CA3 is not an accurate readout of the neural activity associated with hippocampus-dependent rapid memory retrieval. PMID:25512571

  16. 40 CFR 450.21 - Effluent limitations reflecting the best practicable technology currently available (BPT).

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... the best practicable technology currently available (BPT). Except as provided in 40 CFR 125.30 through... velocity within the site to minimize soil erosion; (2) Control stormwater discharges, including both peak... streambank erosion; (3) Minimize the amount of soil exposed during construction activity; (4) Minimize...

  17. 40 CFR 450.21 - Effluent limitations reflecting the best practicable technology currently available (BPT).

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... the best practicable technology currently available (BPT). Except as provided in 40 CFR 125.30 through... velocity within the site to minimize soil erosion; (2) Control stormwater discharges, including both peak... streambank erosion; (3) Minimize the amount of soil exposed during construction activity; (4) Minimize...

  18. Dominant male song performance reflects current immune state in a cooperatively breeding songbird.

    PubMed

    York, Jenny E; Radford, Andrew N; Groothuis, Ton G; Young, Andrew J

    2016-02-01

    Conspicuous displays are thought to have evolved as signals of individual "quality", though precisely what they encode remains a focus of debate. While high quality signals may be produced by high quality individuals due to "good genes" or favourable early-life conditions, whether current immune state also impacts signalling performance remains poorly understood, particularly in social species. Here, we experimentally demonstrate that male song performance is impaired by immune system activation in the cooperatively breeding white-browed sparrow weaver (Plocepasser mahali). We experimentally activated the immune system of free-living dominant males via subcutaneous injection of phytohemagglutinin (PHA) and contrasted its effects with those of a control (phosphate buffered saline) injection. PHA-challenged males showed significant reductions in both the duration and the rate of their song performance, relative to controls, and this could not be readily attributed to effects of the challenge on body mass, as no such effects were detected. Furthermore, male song performance prior to immune-challenge predicted the scale of the inflammatory response to the challenge. Our findings suggest that song performance characteristics are impacted by current immune state. This link between current state and signal performance might therefore contribute to enforcing the honesty of signal performance characteristics. Impacts of current state on signaling may be of particular importance in social species, where subordinates may benefit from an ability to identify and subsequently challenge same-sex dominants in a weakened state. PMID:26811745

  19. Reflections on current methods for evaluating skills during joint replacement surgery: a scoping review.

    PubMed

    Sonnadara, R; McQueen, S; Mironova, P; Safir, O; Nousiainen, M; Ferguson, P; Alman, B; Kraemer, W; Reznick, R

    2013-11-01

    Valid and reliable techniques for assessing performance are essential to surgical education, especially with the emergence of competency-based frameworks. Despite this, there is a paucity of adequate tools for the evaluation of skills required during joint replacement surgery. In this scoping review, we examine current methods for assessing surgeons' competency in joint replacement procedures in both simulated and clinical environments. The ability of many of the tools currently in use to make valid, reliable and comprehensive assessments of performance is unclear. Furthermore, many simulation-based assessments have been criticised for a lack of transferability to the clinical setting. It is imperative that more effective methods of assessment are developed and implemented in order to improve our ability to evaluate the performance of skills relating to total joint replacement. This will enable educators to provide formative feedback to learners throughout the training process to ensure that they have attained core competencies upon completion of their training. This should help ensure positive patient outcomes as the surgical trainees enter independent practice. PMID:24151260

  20. Quantification of portal-bridging fibrosis area more accurately reflects fibrosis stage and liver stiffness than whole fibrosis or perisinusoidal fibrosis areas in chronic hepatitis C.

    PubMed

    Sandrini, Jérémy; Boursier, Jérôme; Chaigneau, Julien; Sturm, Nathalie; Zarski, Jean-Pierre; Le Bail, Brigitte; de Ledinghen, Victor; Calès, Paul; Rousselet, Marie-Christine

    2014-07-01

    early fibrosis stages but did not increase in septal or cirrhotic stages and that the portal-bridging fibrosis area appeared as a more accurate tool to assess fibrosis progression than the whole fibrosis area. PMID:24390214

  1. Code Validation for Eddy Current Modeling: Tube Inspection with Reflection Differential Probes

    SciTech Connect

    Schumm, A.; Nakagawa, N.

    2005-04-09

    Simulation results of the eddy current modeling code ECSIM on an Inconel tube mock-up were compared to existing experimental results on inner and outer circumferential notches inspected at two different frequencies, observing the influence of a geometrical effect such as tube thickness. The EC probe used for this setup represented a number of difficulties, such as a ferrite core for the excitation coil and a differential pickup coil arrangement with a small inner diameter. The results were instructive, showing that special care must be taken to generate highly symmetrical meshes, as minor differences are amplified by the differential setup. We present qualitative and quantitative results and focus on the lessons learned from this code validation exercise.

  2. Reflections on the state of current debate over physician-assisted suicide and euthanasia.

    PubMed

    Winkler, Earl

    1995-07-01

    This paper is part of a larger project. My overall aim is to argue that the evolution of familiar forms of termination of life sustaining treatment, constituting so called passive euthanasia, has severely undercut the logic of every form of reasoning that has traditionally been used to oppose active euthanasia and assistance in suicide. Basically, there are two such forms of traditional opposition, each represented in a range of different versions. There is the inevitable argument concerning social utilities -- that permitting euthanasia and assisted suicide will have bad social consequences. But more fundamentally, the idea persists that killing is intrinsically worse than letting-die in some sense that justifies the current practice of prohibiting the first while allowing the latter. In this paper, I first consider this latter claim. My ultimate strategy, as I have said, is to show that the nature of certain things we have all come to approve regarding termination of treatment makes it next to impossible to convincingly explain, in either of these ways, what is wrong with certain forms of assistance in suicide and euthanasia. In the second part of this paper I take another step in this direction by discussing, in a preliminary way, a special case of the argument from social risks. PMID:11653048

  3. Reflections on the current status of the national sickle cell disease program in the United States.

    PubMed

    Scott, R B

    1979-07-01

    Some clouds of concern now appear on the horizon for the national sickle cell disease program. There is flagging general attention by the black population and a dilution of interest in and visibility of the sickle cell problem brought about by political maneuvering to bring the program under the legislative umbrella of many other genetic diseases (which occur predominantly in Caucasians). In addition, the federal program has recently phased-out six comprehensive sickle cell centers and imposed budgetary cutbacks in the remaining centers. The victims of this disease, the black population in general, and the researchers and investigators who seek ways to bring this disease under control need reassurance from the current national administration that the sickle cell program will not be permitted to die a slow death from financial attrition, attenuation of interest, and skillful neglect leading to the phasing-out of another "minority project." The national sickle cell program, in the relatively short span of six years, has made significant and notable progress not only in research endeavor but also in improved patient care and community-wide education. In this context, certainly, the positive aspects of the national sickle cell disease program continue to far outweigh any negative ones.(1) PMID:529329

  4. A spatially nonselective baseline signal in parietal cortex reflects the probability of a monkey's success on the current trial.

    PubMed

    Zhang, Mingsha; Wang, Xiaolan; Goldberg, Michael E

    2014-06-17

    We recorded the activity of neurons in the lateral intraparietal area of two monkeys while they performed two similar visual search tasks, one difficult, one easy. Each task began with a period of fixation followed by an array consisting of a single capital T and a number of lowercase t's. The monkey had to find the capital T and report its orientation, upright or inverted, with a hand movement. In the easy task the monkey could explore the array with saccades. In the difficult task the monkey had to continue fixating and find the capital T in the visual periphery. The baseline activity measured during the fixation period, at a time in which the monkey could not know if the impending task would be difficult or easy or where the target would appear, predicted the monkey's probability of success or failure on the task. The baseline activity correlated inversely with the monkey's recent history of success and directly with the intensity of the response to the search array on the current trial. The baseline activity was unrelated to the monkey's spatial locus of attention as determined by the location of the cue in a cued visual reaction time task. We suggest that rather than merely reflecting the noise in the system, the baseline signal reflects the cortical manifestation of modulatory state, motivational, or arousal pathways, which determine the efficiency of cortical sensorimotor processing and the quality of the monkey's performance. PMID:24889623

  5. St. Augustine’s Reflections on Memory and Time and the Current Concept of Subjective Time in Mental Time Travel

    PubMed Central

    Manning, Liliann; Cassel, Daniel; Cassel, Jean-Christophe

    2013-01-01

    Reconstructing the past and anticipating the future, i.e., the ability of travelling in mental time, is thought to be at the heart of consciousness and, by the same token, at the center of human cognition. This extraordinary mental activity is possible thanks to the ability of being aware of ‘subjective time’. In the present study, we attempt to trace back the first recorded reflections on the relations between time and memory, to the end of the fourth century’s work, the Confessions, by the theologian and philosopher, St. Augustine. We concentrate on Book 11, where he extensively developed a series of articulated and detailed observations on memory and time. On the bases of selected paragraphs, we endeavor to highlight some concepts that may be considered as the product of the first or, at least, very early reflections related to our current notions of subjective time in mental time travel. We also draw a fundamental difference inherent to the frameworks within which the questions were raised. The contribution of St. Augustine on time and memory remains significant, notwithstanding the 16 centuries elapsed since it was made, likely because of the universality of its contents. PMID:25379236

  6. Accurate blackbodies

    NASA Astrophysics Data System (ADS)

    Latvakoski, Harri M.; Watson, Mike; Topham, Shane; Scott, Deron; Wojcik, Mike; Bingham, Gail

    2010-07-01

    Infrared radiometers and spectrometers generally use blackbodies for calibration, and with the high accuracy needs of upcoming missions, blackbodies capable of meeting strict accuracy requirements are needed. One such mission, the NASA climate science mission Climate Absolute Radiance and Refractivity Observatory (CLARREO), which will measure Earth's emitted spectral radiance from orbit, has an absolute accuracy requirement of 0.1 K (3σ) at 220 K over most of the thermal infrared. Space Dynamics Laboratory (SDL) has a blackbody design capable of meeting strict modern accuracy requirements. This design is relatively simple to build, was developed for use on the ground or onorbit, and is readily scalable for aperture size and required performance. These-high accuracy blackbodies are currently in use as a ground calibration unit and with a high-altitude balloon instrument. SDL is currently building a prototype blackbody to demonstrate the ability to achieve very high accuracy, and we expect it to have emissivity of ~0.9999 from 1.5 to 50 μm, temperature uncertainties of ~25 mK, and radiance uncertainties of ~10 mK due to temperature gradients. The high emissivity and low thermal gradient uncertainties are achieved through cavity design, while the low temperature uncertainty is attained by including phase change materials such as mercury, gallium, and water in the blackbody. Blackbody temperature sensors are calibrated at the melt points of these materials, which are determined by heating through their melt point. This allows absolute temperature calibration traceable to the SI temperature scale.

  7. Oxygen vacancies induced Spin polarized current in Co-doped ZnO by Andreev reflection technique

    NASA Astrophysics Data System (ADS)

    Yang, Kung-Shang; Chou, Hsiung; Chan, Wen Ling; Chen, Bo-Yu; Shang-Fan Lee Collaboration

    Dilute magnetic semiconductor (DMO) is a semiconducting system with spin-polarized carriers and magnetic properties. However, since most studies had been focused on existence of FM, the proportion of spin-polarized current (SPC) in DMO is far from being determined. We used Point-contact Andreev reflection measurements on various Zn0.95Co0.05O thin films, with controlled oxygen vacancies by sputtering in various H2 partial pressure with Ar atmosphere. We found that conductance versus voltage (G-V) spectra suppresses as oxygen vacancy concentration increases. It indicates oxygen vacancies play significant role in inducing the SPC. To understand the origin of spin polarized current at the interface of the superconducting tip/CZO system, we use modified Blonder-Tinkham-Klapwijk (MBTK) model in ballistic and diffusive regime to interpret GV curve. The extracted SPC value were up to 70% in ballistic regime and 65% in diffusive regime. The results suggest tiny routes have been formed by oxygen vacancies which are extended throughout the whole films. This result confirmed that MBTK model in ballistic regime is more suitable for our GV spectra and this explains the observation of such a high SPC Institute of Physics, Academia Sinica Taiwan.

  8. Approaching system equilibrium with accurate or not accurate feedback information in a two-route system

    NASA Astrophysics Data System (ADS)

    Zhao, Xiao-mei; Xie, Dong-fan; Li, Qi

    2015-02-01

    With the development of intelligent transport system, advanced information feedback strategies have been developed to reduce traffic congestion and enhance the capacity. However, previous strategies provide accurate information to travelers and our simulation results show that accurate information brings negative effects, especially in delay case. Because travelers prefer to the best condition route with accurate information, and delayed information cannot reflect current traffic condition but past. Then travelers make wrong routing decisions, causing the decrease of the capacity and the increase of oscillations and the system deviating from the equilibrium. To avoid the negative effect, bounded rationality is taken into account by introducing a boundedly rational threshold BR. When difference between two routes is less than the BR, routes have equal probability to be chosen. The bounded rationality is helpful to improve the efficiency in terms of capacity, oscillation and the gap deviating from the system equilibrium.

  9. Cost reduction and minimization of land based on an accurate determination of fault current distribution in shield wires and grounding systems

    SciTech Connect

    Daily, W.K. ); Dawalibi, F. )

    1993-01-01

    Careful analysis of Fault Current Distribution in neutral metallic paths, Power System Protection requirements and Ground Potential Rise (GPR) evaluations were carried out at FPL's Lauderdale Power Plant and associated switchyard. These studies resulted in substantial cost savings and land utilization minimization for the power system expansions at Lauderdale Plant by confirming that the in-situ expansion and reconfiguration aimed at constructing two electrically independent substations sharing the same site and grounding system is a sound economical alternative to the construction of a new substation and associated significant site preparation and construction costs. This paper describes the methodology used to conduct this study.

  10. Underrepresentation of Culturally Different Students in Gifted Education: Reflections about Current Problems and Recommendations for the Future

    ERIC Educational Resources Information Center

    Ford, Donna Y.

    2010-01-01

    For almost two decades, the author has devoted her professional life to the field of gifted education, as have others. More than any time in her career, she finds herself reflecting even more so on the persistent or stubborn problem of underrepresentation among Black and Hispanic students in gifted education. Is this more frequent self-reflection…

  11. Development and Evaluation of an Inquiry-Based Elementary Science Teacher Education Program Reflecting Current Reform Movements

    NASA Astrophysics Data System (ADS)

    Luera, Gail R.; Otto, Charlotte A.

    2005-08-01

    The National Science Education Standards (National Research Council 1996, National science education standards. Washington, DC: National Academy Press) and various other national and state documents call for teachers who possess science content knowledge, employ an inquiry approach in teaching, and engage in reflective practices. This paper describes a rationale for choosing particular recommendations to implement and how we incorporated those as we revised our elementary science education program. An analysis of the impact of the reformed inquiry-based content courses revealed that students who take more than one reformed content course improve their science content knowledge and efficacy towards teaching science significantly more than students who take fewer courses.

  12. Enhanced light output power in InGaN/GaN light-emitting diodes with a high reflective current blocking layer

    NASA Astrophysics Data System (ADS)

    Xiaojie, Zhang; Ruixia, Yang; Jinghui, Wang

    2012-07-01

    The light output power of an InGaN/GaN light-emitting diode is improved by using a SiO2/TiO2 distributed Bragg reflector (DBR) and an Al mirror as a hybrid reflective current blocking layer (CBL). Such a hybrid reflective CBL not only plays the role of the CBL by enhancing current spreading but also plays the role of a reflector by preventing photons near the p-electrode pad from being absorbed by a metal electrode. At a wavelength of 455 nm, a 1.5-pair of SiO2/TiO2 DBR and an Al mirror (i.e. 1.5-pair DBR+Al) deposited on a p-GaN layer showed a normal-incidence reflectivity as high as 97.8%. With 20 mA current injection, it was found that the output power was 25.26, 24.45, 23.58 and 22.45 mW for the LED with a 1.5-pair DBR+Al CBL, a 3-pair DBR CBL, SiO2 CBL and without a CBL, respectively.

  13. Incidence and reflection of internal waves and wave-induced currents at a jump in buoyancy frequency

    NASA Astrophysics Data System (ADS)

    McHugh, J. P.

    2014-03-01

    Weakly nonlinear internal gravity waves are treated in a two-layer fluid with a set of nonlinear Schrodinger equations. The layers have a sharp interface with a jump in buoyance frequency approximately modelling the tropopause. The waves are periodic in the horizontal but modulated in the vertical and Boussinesq flow is assumed. The equation governing the incident wave packet is directly coupled to the equation for the reflected packet, while the equation governing transmitted waves is only coupled at the interface. Solutions are obtained numerically. The results indicate that the waves create a mean flow that is strong near and underneath the interface, and discontinuous at the interface. Furthermore, the mean flow has an oscillatory component with a vertical wavelength that decreases as the wave packet interacts with the interface.

  14. Incidence and reflection of internal waves and wave-induced currents at a jump in buoyancy frequency

    NASA Astrophysics Data System (ADS)

    McHugh, J. P.

    2015-05-01

    Weakly nonlinear internal gravity waves are treated in a two-layer fluid with a set of nonlinear Schrodinger equations. The layers have a sharp interface with a jump in buoyancy frequency approximately modeling the tropopause. The waves are periodic in the horizontal but modulated in the vertical and Boussinesq flow is assumed. The equation governing the incident wave packet is directly coupled to the equation for the reflected packet, while the equation governing transmitted waves is only coupled at the interface. Solutions are obtained numerically. The results indicate that the waves create a mean flow that is strong near and underneath the interface, and discontinuous at the interface. Furthermore, the mean flow has an oscillatory component that can contaminate the wave envelope and has a vertical wavelength that decreases as the wave packet interacts with the interface.

  15. Healthy Universities: current activity and future directions--findings and reflections from a national-level qualitative research study.

    PubMed

    Dooris, Mark; Doherty, Sharon

    2010-09-01

    This qualitative study used questionnaires to scope and explore 'healthy universities' activity taking place within English higher education institutions (HEIs). The findings revealed a wealth of health-related activity and confirmed growing interest in the healthy universities approach--reflecting an increasing recognition that investment for health within the sector will contribute not only to health targets but also to mainstream agendas such as staff and student recruitment, experience and retention; and institutional and societal productivity and sustainability. However, they also suggested that, while there is growing understanding of the need for a comprehensive whole system approach to improving health within higher education settings, there are a number of very real challenges--including a lack of rigorous evaluation, the difficulty of integrating health into a 'non-health' sector and the complexity of securing sustainable cultural change. Noting that health and well-being remain largely marginal to the core mission and organization of higher education, the article goes on to reflect on the wider implications for future research and policy at national and international levels. Within England, whereas there are Healthy Schools and Healthy Further Education Programmes, there is as yet no government-endorsed programme for universities. Similarly, at an international level, there has been no systematic investment in higher education mirroring the comprehensive and multifaceted Health Promoting Schools Programme. Key issues highlighted are: securing funding for evaluative research within and across HEIs to enable the development of a more robust evidence base for the approach; advocating for an English National Healthy Higher Education Programme that can help to build consistency across the entire spectrum of education; and exploring with the World Health Organization (WHO) and the International Union for Health Promotion and Education (IUHPE) the feasibility

  16. The Pursuit of K: Reflections on the Current State-of-the-Art in Stress Intensity Factor Solutions for Practical Aerospace Applications

    NASA Technical Reports Server (NTRS)

    CraigMcClung, R.; Lee, Yi-Der; Cardinal, Joseph W.; Guo, Yajun

    2012-01-01

    The elastic stress intensity factor (SIF, commonly denoted as K) is the foundation of practical fracture mechanics (FM) analysis for aircraft structures. This single parameter describes the first-order effects of stress magnitude and distribution as well as the geometry of both structure/component and crack. Hence, the calculation of K is often the most significant step in fatigue analysis based on FM. This presentation will provide several reflections on the current state-of-the-art in SIF solution methods used for practical aerospace applications, including a brief historical perspective, descriptions of some recent and ongoing advances, and comments on some remaining challenges. Newman and Raju made significant early contributions to practical structural analysis by developing closed-form SIF equations for surface and corner cracks in simplified geometries, often based on empirical fits of finite element (FE) solutions. Those solutions (and others like them) were sometimes revised as new analyses were conducted or limitations discovered. The foundational solutions have exhibited striking longevity, despite the relatively "coarse" FE models employed many decades ago. However, in recent years, the accumulation of different generations of solutions for the same nominal geometry has led to some confusion (which solution is correct?), and steady increases in computational capabilities have facilitated the discovery of inaccuracies in some (not all!) of the legacy solutions. Some examples of problems and solutions are presented and discussed, including the challenge of maintaining consistency with legacy design applications. As computational power has increased, the prospect of calculating large numbers of SIF solutions for specific complex geometries with advanced numerical methods has grown more attractive. Fawaz and Andersson, for example, have been generating literally millions of new SIF solutions for different combinations of multiple cracks under simplified

  17. Accurate measurement of time

    NASA Astrophysics Data System (ADS)

    Itano, Wayne M.; Ramsey, Norman F.

    1993-07-01

    The paper discusses current methods for accurate measurements of time by conventional atomic clocks, with particular attention given to the principles of operation of atomic-beam frequency standards, atomic hydrogen masers, and atomic fountain and to the potential use of strings of trapped mercury ions as a time device more stable than conventional atomic clocks. The areas of application of the ultraprecise and ultrastable time-measuring devices that tax the capacity of modern atomic clocks include radio astronomy and tests of relativity. The paper also discusses practical applications of ultraprecise clocks, such as navigation of space vehicles and pinpointing the exact position of ships and other objects on earth using the GPS.

  18. Current status of quality evaluation of nursing care through director review and reflection from the Nursing Quality Control Centers

    PubMed Central

    Duan, Xia; Shi, Yan

    2014-01-01

    Background: The quality evaluation of nursing care is a key link in medical quality management. It is important and worth studying for the nursing supervisors to know the disadvantages during the process of quality evaluation of nursing care and then to improve the whole nursing quality. This study was to provide director insight on the current status of quality evaluation of nursing care from Nursing Quality Control Centers (NQCCs). Material and Methods: This qualitative study used a sample of 12 directors from NQCCs who were recruited from 12 provinces in China to evaluate the current status of quality evaluation of nursing care. Data were collected by in-depth interviews. Content analysis method was used to analyze the data. Results: Four themes emerged from the data: 1) lag of evaluation index; 2) limitations of evaluation content; 3) simplicity of evaluation method; 4) excessive emphasis on terminal quality. Conclusion: It is of great realistic significance to ameliorate nursing quality evaluation criteria, modify the evaluation content based on patient needs-oriented idea, adopt scientific evaluation method to evaluate nursing quality, and scientifically and reasonably draw horizontal comparisons of nursing quality between hospitals, as well as longitudinal comparisons of a hospital’s nursing quality. These methods mentioned above can all enhance a hospital’s core competitiveness and benefit more patients. PMID:25419427

  19. Reflecting Reflective Practice

    ERIC Educational Resources Information Center

    Galea, Simone

    2012-01-01

    This paper demystifies reflective practice on teaching by focusing on the idea of reflection itself and how it has been conceived by two philosophers, Plato and Irigaray. It argues that reflective practice has become a standardized method of defining the teacher in teacher education and teacher accreditation systems. It explores how practices of…

  20. Focus group reflections on the current and future state of cognitive assessment tools in geriatric health care

    PubMed Central

    Whitehead, Jocelyne C; Gambino, Sara A; Richter, Jeffrey D; Ryan, Jennifer D

    2015-01-01

    Objective This study provides insight into the thoughts and opinions of geriatric health-care professionals toward cognitive assessments and the use of emerging technologies, such as eye-tracking, to supplement current tools. Methods Two focus group sessions were conducted with nurses and physicians who routinely administer neurocognitive assessments to geriatric populations. Video recordings of the focus group sessions were transcribed and a thematic analysis was performed. Results Participants reported the need for assessment and diagnostic tools that are accessible and efficient, and that are capable of accommodating the rapid growth in the aging population. The prevalence of more complex ailments experienced by older adults has had repercussions in the quality of care that the clients receive, and has contributed to lengthy wait times and resource shortages. Health-care professionals stated that they are hampered by the disjointed structure of the health-care system and that they would benefit from a more efficient allocation of responsibilities made possible through tools that did not require extensive training or certification. Eyetracking-based cognitive assessments were thought to strongly complement this system, yet it was thought that difficulty would be faced in gaining the support and increased uptake by health-care professionals due to the nonintuitive relationship between eyetracking and cognition. Conclusion The findings suggest that health-care professionals are receptive to the use of eyetracking technology to assess for cognitive health as it would conserve resources by allowing frontline staff to administer assessments with minimal training. PMID:26109860

  1. Accurate quantum chemical calculations

    NASA Technical Reports Server (NTRS)

    Bauschlicher, Charles W., Jr.; Langhoff, Stephen R.; Taylor, Peter R.

    1989-01-01

    An important goal of quantum chemical calculations is to provide an understanding of chemical bonding and molecular electronic structure. A second goal, the prediction of energy differences to chemical accuracy, has been much harder to attain. First, the computational resources required to achieve such accuracy are very large, and second, it is not straightforward to demonstrate that an apparently accurate result, in terms of agreement with experiment, does not result from a cancellation of errors. Recent advances in electronic structure methodology, coupled with the power of vector supercomputers, have made it possible to solve a number of electronic structure problems exactly using the full configuration interaction (FCI) method within a subspace of the complete Hilbert space. These exact results can be used to benchmark approximate techniques that are applicable to a wider range of chemical and physical problems. The methodology of many-electron quantum chemistry is reviewed. Methods are considered in detail for performing FCI calculations. The application of FCI methods to several three-electron problems in molecular physics are discussed. A number of benchmark applications of FCI wave functions are described. Atomic basis sets and the development of improved methods for handling very large basis sets are discussed: these are then applied to a number of chemical and spectroscopic problems; to transition metals; and to problems involving potential energy surfaces. Although the experiences described give considerable grounds for optimism about the general ability to perform accurate calculations, there are several problems that have proved less tractable, at least with current computer resources, and these and possible solutions are discussed.

  2. How Current Clinical Practice Guidelines for Low Back Pain Reflect Traditional Medicine in East Asian Countries: A Systematic Review of Clinical Practice Guidelines and Systematic Reviews

    PubMed Central

    Cho, Hyun-Woo; Hwang, Eui-Hyoung; Lim, Byungmook; Heo, Kwang-Ho; Liu, Jian-Ping; Tsutani, Kiichiro; Lee, Myeong Soo; Shin, Byung-Cheul

    2014-01-01

    Objectives The aims of this study were to investigate whether there is a gap between evidence of traditional medicine (TM) interventions in East-Asian countries from the current Clinical Practice Guidelines (CPGs) and evidence from current systematic reviews and meta-analyses (SR-MAs) and to analyze the impact of this gap on present CPGs. Methods We examined 5 representative TM interventions in the health care systems of East-Asian countries. We searched seven relevant databases for CPGs to identify whether core CPGs included evidence of TM interventions, and we searched 11 databases for SR-MAs to re-evaluate current evidence on TM interventions. We then compared the gap between the evidence from CPGs and SR-MAs. Results Thirteen CPGs and 22 SR-MAs met our inclusion criteria. Of the 13 CPGs, 7 CPGs (54%) mentioned TM interventions, and all were for acupuncture (only one was for both acupuncture and acupressure). However, the CPGs did not recommend acupuncture (or acupressure). Of 22 SR-MAs, 16 were for acupuncture, 5 for manual therapy, 1 for cupping, and none for moxibustion and herbal medicine. Comparing the evidence from CPGs and SR-MAs, an underestimation or omission of evidence for acupuncture, cupping, and manual therapy in current CPGs was detected. Thus, applying the results from the SR-MAs, we moderately recommend acupuncture for chronic LBP, but we inconclusively recommend acupuncture for (sub)acute LBP due to the limited current evidence. Furthermore, we weakly recommend cupping and manual therapy for both (sub)acute and chronic LBP. We cannot provide recommendations for moxibustion and herbal medicine due to a lack of evidence. Conclusions The current CPGs did not fully reflect the evidence for TM interventions. As relevant studies such as SR-MAs are conducted and evidence increases, the current evidence on acupuncture, cupping, and manual therapy should be rigorously considered in the process of developing or updating the CPG system. PMID:24505363

  3. Reflected Glory

    NASA Astrophysics Data System (ADS)

    2011-02-01

    The nebula Messier 78 takes centre stage in this image taken with the Wide Field Imager on the MPG/ESO 2.2-metre telescope at the La Silla Observatory in Chile, while the stars powering the bright display take a backseat. The brilliant starlight ricochets off dust particles in the nebula, illuminating it with scattered blue light. Igor Chekalin was the overall winner of ESO's Hidden Treasures 2010 astrophotography competition with his image of this stunning object. Messier 78 is a fine example of a reflection nebula. The ultraviolet radiation from the stars that illuminate it is not intense enough to ionise the gas to make it glow - its dust particles simply reflect the starlight that falls on them. Despite this, Messier 78 can easily be observed with a small telescope, being one of the brightest reflection nebulae in the sky. It lies about 1350 light-years away in the constellation of Orion (The Hunter) and can be found northeast of the easternmost star of Orion's belt. This new image of Messier 78 from the MPG/ESO 2.2-metre telescope at the La Silla Observatory is based on data selected by Igor Chekalin in his winning entry to the Hidden Treasures competition [1]. The pale blue tint seen in the nebula in this picture is an accurate representation of its dominant colour. Blue hues are commonly seen in reflection nebulae because of the way the starlight is scattered by the tiny dust particles that they contain: the shorter wavelength of blue light is scattered more efficiently than the longer wavelength red light. This image contains many other striking features apart from the glowing nebula. A thick band of obscuring dust stretches across the image from the upper left to the lower right, blocking the light from background stars. In the bottom right corner, many curious pink structures are also visible, which are created by jets of material being ejected from stars that have recently formed and are still buried deep in dust clouds. Two bright stars, HD 38563A and

  4. Conductance and persistent current in quasi-one-dimensional systems with grain boundaries: Effects of the strongly reflecting and columnar grains

    NASA Astrophysics Data System (ADS)

    Feilhauer, J.; Moško, M.

    2011-08-01

    We study mesoscopic transport in the quasi-one-dimensional wires and rings made of a two-dimensional conductor of width W and length L≫W. Our aim is to compare an impurity-free conductor with grain boundaries with a grain-free conductor with impurity disorder. A single grain boundary is modeled as a set of the two-dimensional δ-function-like barriers positioned equidistantly on a straight line and disorder is emulated by a large number of such straight lines, intersecting the conductor with random orientation in random positions. The impurity disorder is modeled by the two-dimensional δ barriers with the randomly chosen positions and signs. The electron transmission through the wires is calculated by the scattering-matrix method, and the Landauer conductance is obtained. Moreover, we calculate the persistent current in the rings threaded by magnetic flux: We incorporate into the scattering-matrix method the flux-dependent cyclic boundary conditions and we introduce a trick allowing us to study the persistent currents in rings of almost realistic size. We mainly focus on the numerical results for L much larger than the electron mean-free path, when the transport is diffusive. If the grain boundaries are weakly reflecting, the systems with grain boundaries show the same (mean) conductance and the same (typical) persistent current as the systems with impurities, and the results also agree with the single-particle theories treating disorder as a white-noise-like potential. If the grain boundaries are strongly reflecting, the rings with the grain boundaries show the typical persistent currents about three times larger than the white-noise-based theory, thus resembling the experimental data of Jariwala [Phys. Rev. Lett.PRLTAO0031-900710.1103/PhysRevLett.86.1594 86, 1594 (2001)]. Finally, we extend our study to the three-dimensional wires/rings with columnar grains. Due to the columnar shape of the grains, the resulting persistent current exceeds the white

  5. Evaluation of the Reflection Coefficient of Microstrip Elements for Reflectarray Antennas

    NASA Technical Reports Server (NTRS)

    Rengarajan, Sembiam

    2011-01-01

    Basis functions were studied and identified that provide efficient and accurate solutions for the induced patch currents and the reflection phase in microstrip reflect arrays. The integral equation of an infinite array of microstrip elements in the form of patches or crossed dipoles excited by a uniform plane wave is solved by the method-of-moments. Efficient choices of entire domain basis functions that yield accurate results have been described.

  6. Reflective Teaching

    ERIC Educational Resources Information Center

    Farrell, Thomas S. C.

    2013-01-01

    Thomas Farrell's "Reflective Teaching" outlines four principles that take teachers from just doing reflection to making it a way of being. Using the four principles, Reflective Practice Is Evidence Based, Reflective Practice Involves Dialogue, Reflective Practice Links Beliefs and Practices, and Reflective Practice Is a Way of Life,…

  7. Coordinated Analyses of Antarctic Sediments as Mars Analog Materials Using Reflectance Spectroscopy and Current Flight-Like Instruments for CheMin, SAM and MOMA

    NASA Technical Reports Server (NTRS)

    Bishop, Janice L.; Franz, Heather B.; Goetz, Walter; Blake, David F.; Freissinet, Caroline; Steininger, Harald; Goesmann, Fred; Brinckerhoff, William B.; Getty, Stephanie; Pinnick, Veronica T.; Mahaffy, Paul R.; Dyar, M. Darby

    2013-01-01

    Coordinated analyses of mineralogy and chemistry of sediments from the Antarctic Dry Valleys illustrate how data obtained using flight-ready technology of current NASA and ESA missions can be combined for greater understanding of the samples. Mineralogy was measured by X-ray diffraction (XRD) and visible/ near-infrared (VNIR) reflectance spectroscopy. Chemical analyses utilized a quadrupole mass spectrometer (QMS) to perform pyrolysis-evolved gas analysis (EGA) and gas chromatography-mass spectrometry (GC/MS) both with and without derivatization, as well as laser desorption-mass spectrometry (LD/MS) techniques. These analyses are designed to demonstrate some of the capabilities of near-term landed Mars missions, to provide ground truthing of VNIR reflectance data acquired from orbit by the Compact Reconnaissance Imaging Spectrometer for Mars (CRISM) on MRO and to provide detection limits for surface- operated instruments: the Chemistry and Mineralogy (CheMin) and Sample Analysis at Mars (SAM) instrument suites onboard Mars Science Laboratory (MSL) and the Mars Organic Molecule Analyzer (MOMA) onboard ExoMars-2018. The new data from this study are compared with previous analyses of the sediments performed with other techniques. Tremolite was found in the oxic region samples for the first time using the CheMin-like XRD instrument. The NIR spectral features of tremolite are consistent with those observed in these samples. Although the tremolite bands are weak in spectra of these samples, spectral features near 2.32 and 2.39 micrometers could be detected by CRISM if tremolite is present on the martian surface. Allophane was found to be a good match to weak NIR features at 1.37-1.41, 1.92, and 2.19 micrometers in spectra of the oxic region sediments and is a common component of immature volcanic soils. Biogenic methane was found to be associated with calcite in the oxic region samples by the SAM/EGA instrument and a phosphoric acid derivative was found in the anoxic

  8. Coordinated analyses of Antarctic sediments as Mars analog materials using reflectance spectroscopy and current flight-like instruments for CheMin, SAM and MOMA

    NASA Astrophysics Data System (ADS)

    Bishop, Janice L.; Franz, Heather B.; Goetz, Walter; Blake, David F.; Freissinet, Caroline; Steininger, Harald; Goesmann, Fred; Brinckerhoff, William B.; Getty, Stephanie; Pinnick, Veronica T.; Mahaffy, Paul R.; Dyar, M. Darby

    2013-06-01

    Coordinated analyses of mineralogy and chemistry of sediments from the Antarctic Dry Valleys illustrate how data obtained using flight-ready technology of current NASA and ESA missions can be combined for greater understanding of the samples. Mineralogy was measured by X-ray diffraction (XRD) and visible/near-infrared (VNIR) reflectance spectroscopy. Chemical analyses utilized a quadrupole mass spectrometer (QMS) to perform pyrolysis-evolved gas analysis (EGA) and gas chromatography-mass spectrometry (GC/MS) both with and without derivatization, as well as laser desorption-mass spectrometry (LD/MS) techniques. These analyses are designed to demonstrate some of the capabilities of near-term landed Mars missions, to provide ground truthing of VNIR reflectance data acquired from orbit by the Compact Reconnaissance Imaging Spectrometer for Mars (CRISM) on MRO and to provide detection limits for surface-operated instruments: the Chemistry and Mineralogy (CheMin) and Sample Analysis at Mars (SAM) instrument suites onboard Mars Science Laboratory (MSL) and the Mars Organic Molecule Analyzer (MOMA) onboard ExoMars-2018. The new data from this study are compared with previous analyses of the sediments performed with other techniques. Tremolite was found in the oxic region samples for the first time using the CheMin-like XRD instrument. The NIR spectral features of tremolite are consistent with those observed in these samples. Although the tremolite bands are weak in spectra of these samples, spectral features near 2.32 and 2.39 μm could be detected by CRISM if tremolite is present on the martian surface. Allophane was found to be a good match to weak NIR features at ˜1.37-1.41, 1.92, and 2.19 μm in spectra of the oxic region sediments and is a common component of immature volcanic soils. Biogenic methane was found to be associated with calcite in the oxic region samples by the SAM/EGA instrument and a phosphoric acid derivative was found in the anoxic region sample using

  9. Grading More Accurately

    ERIC Educational Resources Information Center

    Rom, Mark Carl

    2011-01-01

    Grades matter. College grading systems, however, are often ad hoc and prone to mistakes. This essay focuses on one factor that contributes to high-quality grading systems: grading accuracy (or "efficiency"). I proceed in several steps. First, I discuss the elements of "efficient" (i.e., accurate) grading. Next, I present analytical results…

  10. Accurate monotone cubic interpolation

    NASA Technical Reports Server (NTRS)

    Huynh, Hung T.

    1991-01-01

    Monotone piecewise cubic interpolants are simple and effective. They are generally third-order accurate, except near strict local extrema where accuracy degenerates to second-order due to the monotonicity constraint. Algorithms for piecewise cubic interpolants, which preserve monotonicity as well as uniform third and fourth-order accuracy are presented. The gain of accuracy is obtained by relaxing the monotonicity constraint in a geometric framework in which the median function plays a crucial role.

  11. Accurate Finite Difference Algorithms

    NASA Technical Reports Server (NTRS)

    Goodrich, John W.

    1996-01-01

    Two families of finite difference algorithms for computational aeroacoustics are presented and compared. All of the algorithms are single step explicit methods, they have the same order of accuracy in both space and time, with examples up to eleventh order, and they have multidimensional extensions. One of the algorithm families has spectral like high resolution. Propagation with high order and high resolution algorithms can produce accurate results after O(10(exp 6)) periods of propagation with eight grid points per wavelength.

  12. Reflection Coefficients.

    ERIC Educational Resources Information Center

    Greenslade, Thomas B., Jr.

    1994-01-01

    Discusses and provides an example of reflectivity approximation to determine whether reflection will occur. Provides a method to show thin-film interference on a projection screen. Also applies the reflectivity concepts to electromagnetic wave systems. (MVL)

  13. Reflectance of aqueous solutions

    NASA Technical Reports Server (NTRS)

    Querry, M. R.

    1972-01-01

    The optical properties and optical constants of water and aqueous solutions were studied to develop an accurate tabulation of graphical representations of the optical constants through a broad spectrum. Manuscripts of articles are presented concerning extinction coefficients, relative specular reflectance, and temperature effect on the water spectrum. Graphs of absolute reflectance, phase shifts, index of refraction, and extinction coefficients for water, heavy water and aqueous solutions are included.

  14. Partial reflections of radio waves from the lower ionosphere

    NASA Technical Reports Server (NTRS)

    Connolly, D. J.; Tanenbaum, S. B.

    1972-01-01

    The addition of phase difference measurements to partial reflection experiments is discussed, and some advantages of measuring electron density this way are pointed out. The additional information obtained reduces the requirement for an accurate predetermination of collision frequency. Calculations are also made to estimate the errors expected in partial-reflection experiments due to the assumption of Fresnel reflection and to the neglect of coupling between modes. In both cases, the errors are found to be of the same order as known errors in the measurements due to current instrumental limitations.

  15. The Reflective Learning Continuum: Reflecting on Reflection

    ERIC Educational Resources Information Center

    Peltier, James W.; Hay, Amanda; Drago, William

    2005-01-01

    The importance of reflection to marketing educators is increasingly recognized. However, there is a lack of empirical research that considers reflection within the context of both the marketing and general business education literature. This article describes the use of an instrument that can be used to measure four identified levels of a…

  16. Renewable liquid reflection grating

    DOEpatents

    Ryutov, Dmitri D.; Toor, Arthur

    2003-10-07

    A renewable liquid reflection grating. Electrodes are operatively connected to a conducting liquid in an arrangement that produces a reflection grating and driven by a current with a resonance frequency. In another embodiment, the electrodes create the grating by a resonant electrostatic force acting on a dielectric liquid.

  17. Reflected Glory

    NASA Astrophysics Data System (ADS)

    2011-02-01

    The nebula Messier 78 takes centre stage in this image taken with the Wide Field Imager on the MPG/ESO 2.2-metre telescope at the La Silla Observatory in Chile, while the stars powering the bright display take a backseat. The brilliant starlight ricochets off dust particles in the nebula, illuminating it with scattered blue light. Igor Chekalin was the overall winner of ESO's Hidden Treasures 2010 astrophotography competition with his image of this stunning object. Messier 78 is a fine example of a reflection nebula. The ultraviolet radiation from the stars that illuminate it is not intense enough to ionise the gas to make it glow - its dust particles simply reflect the starlight that falls on them. Despite this, Messier 78 can easily be observed with a small telescope, being one of the brightest reflection nebulae in the sky. It lies about 1350 light-years away in the constellation of Orion (The Hunter) and can be found northeast of the easternmost star of Orion's belt. This new image of Messier 78 from the MPG/ESO 2.2-metre telescope at the La Silla Observatory is based on data selected by Igor Chekalin in his winning entry to the Hidden Treasures competition [1]. The pale blue tint seen in the nebula in this picture is an accurate representation of its dominant colour. Blue hues are commonly seen in reflection nebulae because of the way the starlight is scattered by the tiny dust particles that they contain: the shorter wavelength of blue light is scattered more efficiently than the longer wavelength red light. This image contains many other striking features apart from the glowing nebula. A thick band of obscuring dust stretches across the image from the upper left to the lower right, blocking the light from background stars. In the bottom right corner, many curious pink structures are also visible, which are created by jets of material being ejected from stars that have recently formed and are still buried deep in dust clouds. Two bright stars, HD 38563A and

  18. How accurate is NETTO

    NASA Technical Reports Server (NTRS)

    Dupont, S.

    1979-01-01

    The historical origin and general history of vertical current total energy variometer, including its optimum airspeed selector ring are reviewed, and some later developments of it are discussed. Polars of three sailplanes of different spans are charted for straight and circling flight, then plotted to reveal their parabolic anomaly and the effect of circling flight sink rate. These effects are further analyzed for their influence on the transient compensation of NETTO variometers as well as the speed ring. Some other disturbances due to the quality of sailplane preparation and flight dynamics are listed. Conclusions are drawn about the problems to pilots from imperfect NETTO variometer compensation and its effect on the maximization of ground speed from the speed ring. A modification for improvements to the speed ring and computer is suggested.

  19. Measuring Light Reflectance of BGO Crystal Surfaces

    SciTech Connect

    Janecek, Martin; Moses, William

    2008-07-28

    A scintillating crystal's surface reflectance has to be well understood in order to accurately predict and optimize the crystal?s light collection through Monte Carlo simulations. In this paper, we measure the inner surface reflectance properties for BGO. The measurements include BGO crystals with a mechanically polished surface, rough-cut surface, and chemically etched surface, and with various reflectors attached, both air- coupled and with coupling compound. The measurements are performed with a laser aimed at the center of a hemispherical shaped BGO crystal. The hemispherical shape eliminates any non-perpendicular angles for light entering and exiting the crystal. The reflected light is collected with an array of photodiodes. The laser can be set at an arbitrary angle, and the photodiode array is rotated to fully cover 2? of solid angle. The current produced in the photodiodes is readout with a digital multimeter connected through a multiplexer. The two rows of photodiodes achieve 5-degree by 4-degree resolution, and the current measurement has a dynamic range of 10^5:1. The acquired data was not described by the commonly assumed linear combination of specular and diffuse (Lambertian) distributions, except for a very few surfaces. Surface roughness proved to be the most important parameter when choosing crystal setup. The reflector choice was of less importance and of almost no consequence for rough-cut surfaces. Pure specular reflection distribution for all incidence angles was measured for polished surfaces with VM2000 film, while the most Lambertian distribution for any surface finish was measured for titanium dioxide paint. The distributions acquired in this paper will be used to create more accurate Monte Carlo models for light reflection distribution within BGO crystals.

  20. Reflected Glory

    ERIC Educational Resources Information Center

    Forster, Colin

    2006-01-01

    The scientific model of how people see things is far removed from children's real-world experience. They know that light is needed in order to see an object, but may not know that light is reflected off the object and some of that light enters the eyes. In this article, the author explores children's understanding of reflection and how to develop…

  1. Na+ current properties in islet α- and β-cells reflect cell-specific Scn3a and Scn9a expression

    PubMed Central

    Zhang, Quan; Chibalina, Margarita V; Bengtsson, Martin; Groschner, Lukas N; Ramracheya, Reshma; Rorsman, Nils J G; Leiss, Veronika; Nassar, Mohammed A; Welling, Andrea; Gribble, Fiona M; Reimann, Frank; Hofmann, Franz; Wood, John N; Ashcroft, Frances M; Rorsman, Patrik

    2014-01-01

    Mouse pancreatic β- and α-cells are equipped with voltage-gated Na+ currents that inactivate over widely different membrane potentials (half-maximal inactivation (V0.5) at −100 mV and −50 mV in β- and α-cells, respectively). Single-cell PCR analyses show that both α- and β-cells have Nav1.3 (Scn3) and Nav1.7 (Scn9a) α subunits, but their relative proportions differ: β-cells principally express Nav1.7 and α-cells Nav1.3. In α-cells, genetically ablating Scn3a reduces the Na+ current by 80%. In β-cells, knockout of Scn9a lowers the Na+ current by >85%, unveiling a small Scn3a-dependent component. Glucagon and insulin secretion are inhibited in Scn3a−/− islets but unaffected in Scn9a-deficient islets. Thus, Nav1.3 is the functionally important Na+ channel α subunit in both α- and β-cells because Nav1.7 is largely inactive at physiological membrane potentials due to its unusually negative voltage dependence of inactivation. Interestingly, the Nav1.7 sequence in brain and islets is identical and yet the V0.5 for inactivation is >30 mV more negative in β-cells. This may indicate the presence of an intracellular factor that modulates the voltage dependence of inactivation. PMID:25172946

  2. Practical aspects of spatially high accurate methods

    NASA Technical Reports Server (NTRS)

    Godfrey, Andrew G.; Mitchell, Curtis R.; Walters, Robert W.

    1992-01-01

    The computational qualities of high order spatially accurate methods for the finite volume solution of the Euler equations are presented. Two dimensional essentially non-oscillatory (ENO), k-exact, and 'dimension by dimension' ENO reconstruction operators are discussed and compared in terms of reconstruction and solution accuracy, computational cost and oscillatory behavior in supersonic flows with shocks. Inherent steady state convergence difficulties are demonstrated for adaptive stencil algorithms. An exact solution to the heat equation is used to determine reconstruction error, and the computational intensity is reflected in operation counts. Standard MUSCL differencing is included for comparison. Numerical experiments presented include the Ringleb flow for numerical accuracy and a shock reflection problem. A vortex-shock interaction demonstrates the ability of the ENO scheme to excel in simulating unsteady high-frequency flow physics.

  3. Alpha Power Increase After Transcranial Alternating Current Stimulation at Alpha Frequency (α-tACS) Reflects Plastic Changes Rather Than Entrainment

    PubMed Central

    Vossen, Alexandra; Gross, Joachim; Thut, Gregor

    2015-01-01

    Background Periodic stimulation of occipital areas using transcranial alternating current stimulation (tACS) at alpha (α) frequency (8–12 Hz) enhances electroencephalographic (EEG) α-oscillation long after tACS-offset. Two mechanisms have been suggested to underlie these changes in oscillatory EEG activity: tACS-induced entrainment of brain oscillations and/or tACS-induced changes in oscillatory circuits by spike-timing dependent plasticity. Objective We tested to what extent plasticity can account for tACS-aftereffects when controlling for entrainment “echoes.” To this end, we used a novel, intermittent tACS protocol and investigated the strength of the aftereffect as a function of phase continuity between successive tACS episodes, as well as the match between stimulation frequency and endogenous α-frequency. Methods 12 healthy participants were stimulated at around individual α-frequency for 11–15 min in four sessions using intermittent tACS or sham. Successive tACS events were either phase-continuous or phase-discontinuous, and either 3 or 8 s long. EEG α-phase and power changes were compared after and between episodes of α-tACS across conditions and against sham. Results α-aftereffects were successfully replicated after intermittent stimulation using 8-s but not 3-s trains. These aftereffects did not reveal any of the characteristics of entrainment echoes in that they were independent of tACS phase-continuity and showed neither prolonged phase alignment nor frequency synchronization to the exact stimulation frequency. Conclusion Our results indicate that plasticity mechanisms are sufficient to explain α-aftereffects in response to α-tACS, and inform models of tACS-induced plasticity in oscillatory circuits. Modifying brain oscillations with tACS holds promise for clinical applications in disorders involving abnormal neural synchrony. PMID:25648377

  4. Technical note: the United States Department of Agriculture beef yield grade equation requires modification to reflect the current longissimus muscle area to hot carcass weight relationship.

    PubMed

    Lawrence, T E; Farrow, R L; Zollinger, B L; Spivey, K S

    2008-06-01

    With the adoption of visual instrument grading, the calculated yield grade can be used for payment to cattle producers selling on grid pricing systems. The USDA beef carcass grading standards include a relationship between required LM area (LMA) and HCW that is an important component of the final yield grade. As noted on a USDA yield grade LMA grid, a 272-kg (600-lb) carcass requires a 71-cm(2) (11.0-in.(2)) LMA and a 454-kg (1,000-lb) carcass requires a 102-cm(2) (15.8-in.(2)) LMA. This is a linear relationship, where required LMA = 0.171(HCW) + 24.526. If a beef carcass has a larger LMA than required, the calculated yield grade is lowered, whereas a smaller LMA than required increases the calculated yield grade. The objective of this investigation was to evaluate the LMA to HCW relationship against data on 434,381 beef carcasses in the West Texas A&M University (WTAMU) Beef Carcass Research Center database. In contrast to the USDA relationship, our data indicate a quadratic relationship [WTAMU LMA = 33.585 + 0.17729(HCW) -0.0000863(HCW(2))] between LMA and HCW whereby, on average, a 272-kg carcass has a 75-cm(2) (11.6-in.(2)) LMA and a 454-kg carcass has a 96-cm(2) (14.9-in.(2)) LMA, indicating a different slope and different intercept than those in the USDA grading standards. These data indicate that the USDA calculated yield grade equation favors carcasses lighter than 363 kg (800 lb) for having above average muscling and penalizes carcasses heavier than 363 kg (800 lb) for having below average muscling. If carcass weights continue to increase, we are likely to observe greater proportions of yield grade 4 and 5 carcasses because of the measurement bias that currently exists in the USDA yield grade equation. PMID:18310492

  5. NNLOPS accurate associated HW production

    NASA Astrophysics Data System (ADS)

    Astill, William; Bizon, Wojciech; Re, Emanuele; Zanderighi, Giulia

    2016-06-01

    We present a next-to-next-to-leading order accurate description of associated HW production consistently matched to a parton shower. The method is based on reweighting events obtained with the HW plus one jet NLO accurate calculation implemented in POWHEG, extended with the MiNLO procedure, to reproduce NNLO accurate Born distributions. Since the Born kinematics is more complex than the cases treated before, we use a parametrization of the Collins-Soper angles to reduce the number of variables required for the reweighting. We present phenomenological results at 13 TeV, with cuts suggested by the Higgs Cross section Working Group.

  6. How to accurately bypass damage

    PubMed Central

    Broyde, Suse; Patel, Dinshaw J.

    2016-01-01

    Ultraviolet radiation can cause cancer through DNA damage — specifically, by linking adjacent thymine bases. Crystal structures show how the enzyme DNA polymerase η accurately bypasses such lesions, offering protection. PMID:20577203

  7. Accurate Evaluation of Quantum Integrals

    NASA Technical Reports Server (NTRS)

    Galant, David C.; Goorvitch, D.

    1994-01-01

    Combining an appropriate finite difference method with Richardson's extrapolation results in a simple, highly accurate numerical method for solving a Schr\\"{o}dinger's equation. Important results are that error estimates are provided, and that one can extrapolate expectation values rather than the wavefunctions to obtain highly accurate expectation values. We discuss the eigenvalues, the error growth in repeated Richardson's extrapolation, and show that the expectation values calculated on a crude mesh can be extrapolated to obtain expectation values of high accuracy.

  8. Reflective Learning

    ERIC Educational Resources Information Center

    Morales, Stephen

    2011-01-01

    In this article, the author presents his study of parent participation at an international school in Spain offering the British curriculum. He used quantitative methods and administered questionnaires to gather data that reflected the views of a large proportion of the school's parent community. He administered semi-structured interviews to gain a…

  9. Estimators of bottom reflectance spectra

    NASA Technical Reports Server (NTRS)

    Estep, L.; Holloway, J.

    1992-01-01

    Estimators of in situ bottom spectral reflectance are calculated from multi-station optical field data gathered with standard instrumentation from different sites. These spectra are then compared to reflectance spectra measured in the laboratory of the bottom sediments collected in the field for the stations at these different sites. The relative fit of the estimated spectral curves to those measured in the laboratory was measured. The most accurate absolute estimation was provided by the single scattering irradiance model.

  10. Learning Design: Reflections upon the Current Landscape

    ERIC Educational Resources Information Center

    Mor, Yishay; Craft, Brock

    2012-01-01

    The mounting wealth of open and readily available information and the accelerated evolution of social, mobile and creative technologies call for a re-conceptualisation of the role of educators: from providers of knowledge to designers of learning. This call is reverberated by the rising trend of research in learning design (LD). Addressing this,…

  11. Normal-reflection image

    SciTech Connect

    Huang, L.; Fehler, Michael C.

    2003-01-01

    Common-angle wave-equation migration using the double-square-root is generally less accurate than the common-shot migration because the wavefield continuation equation for thc former involves additional approximations compared to that for the latter. We present a common-angle wave-equation migration that has the same accuracy as common-shot wave-equation migration. An image obtained from common-angle migration is a four- to five-dimensional output volume for 3D cases. We propose a normal-reflection imaging condition for common-angle migration to produce a 3D output volume for 3D migration. The image is closely related to the normal-reflection coefficients at interfaces. This imaging condition will allow amplitude-preserving migration to generate an image with clear physical meaning.

  12. Accurate definition of brain regions position through the functional landmark approach.

    PubMed

    Thirion, Bertrand; Varoquaux, Gaël; Poline, Jean-Baptiste

    2010-01-01

    In many application of functional Magnetic Resonance Imaging (fMRI), including clinical or pharmacological studies, the definition of the location of the functional activity between subjects is crucial. While current acquisition and normalization procedures improve the accuracy of the functional signal localization, it is also important to ensure that functional foci detection yields accurate results, and reflects between-subject variability. Here we introduce a fast functional landmark detection procedure, that explicitly models the spatial variability of activation foci in the observed population. We compare this detection approach to standard statistical maps peak extraction procedures: we show that it yields more accurate results on simulations, and more reproducible results on a large cohort of subjects. These results demonstrate that explicit functional landmark modeling approaches are more effective than standard statistical mapping for brain functional focus detection. PMID:20879321

  13. Selectively reflective transparent sheets

    NASA Astrophysics Data System (ADS)

    Waché, Rémi; Florescu, Marian; Sweeney, Stephen J.; Clowes, Steven K.

    2015-08-01

    We investigate the possibility to selectively reflect certain wavelengths while maintaining the optical properties on other spectral ranges. This is of particular interest for transparent materials, which for specific applications may require high reflectivity at pre-determined frequencies. Although there exist currently techniques such as coatings to produce selective reflection, this work focuses on new approaches for mass production of polyethylene sheets which incorporate either additives or surface patterning for selective reflection between 8 to 13 μ m. Typical additives used to produce a greenhouse effect in plastics include particles such as clays, silica or hydroxide materials. However, the absorption of thermal radiation is less efficient than the decrease of emissivity as it can be compared with the inclusion of Lambertian materials. Photonic band gap engineering by the periodic structuring of metamaterials is known in nature for producing the vivid bright colors in certain organisms via strong wavelength-selective reflection. Research to artificially engineer such structures has mainly focused on wavelengths in the visible and near infrared. However few studies to date have been carried out to investigate the properties of metastructures in the mid infrared range even though the patterning of microstructure is easier to achieve. We present preliminary results on the diffuse reflectivity using FDTD simulations and analyze the technical feasibility of these approaches.

  14. Haitian reflections.

    PubMed

    Docrat, Fathima

    2010-08-01

    Natural disasters and acts of terrorism demonstrate a similar critical need for national preparedness. As one of a team of volunteers with a local South African NGO who recently went on a medical mission, I would like to share glimpses of our experience and reflect on the mistakes - and also to state the obvious: that we do not learn from our mistakes. A simple literature search has shown that the same mistakes happen repeatedly. 'Humanitarian disasters occur with frightening regularity, yet international responses remain fragmented, with organizations and responders being forced to "reinvent the wheel" with every new event'. This is the result of an obvious lack of preparedness. PMID:20822625

  15. Reflective Packaging

    NASA Technical Reports Server (NTRS)

    1994-01-01

    The aluminized polymer film used in spacecraft as a radiation barrier to protect both astronauts and delicate instruments has led to a number of spinoff applications. Among them are aluminized shipping bags, food cart covers and medical bags. Radiant Technologies purchases component materials and assembles a barrier made of layers of aluminized foil. The packaging reflects outside heat away from the product inside the container. The company is developing new aluminized lines, express mailers, large shipping bags, gel packs and insulated panels for the building industry.

  16. Accurate metacognition for visual sensory memory representations.

    PubMed

    Vandenbroucke, Annelinde R E; Sligte, Ilja G; Barrett, Adam B; Seth, Anil K; Fahrenfort, Johannes J; Lamme, Victor A F

    2014-04-01

    The capacity to attend to multiple objects in the visual field is limited. However, introspectively, people feel that they see the whole visual world at once. Some scholars suggest that this introspective feeling is based on short-lived sensory memory representations, whereas others argue that the feeling of seeing more than can be attended to is illusory. Here, we investigated this phenomenon by combining objective memory performance with subjective confidence ratings during a change-detection task. This allowed us to compute a measure of metacognition--the degree of knowledge that subjects have about the correctness of their decisions--for different stages of memory. We show that subjects store more objects in sensory memory than they can attend to but, at the same time, have similar metacognition for sensory memory and working memory representations. This suggests that these subjective impressions are not an illusion but accurate reflections of the richness of visual perception. PMID:24549293

  17. Accurate radiative transfer calculations for layered media.

    PubMed

    Selden, Adrian C

    2016-07-01

    Simple yet accurate results for radiative transfer in layered media with discontinuous refractive index are obtained by the method of K-integrals. These are certain weighted integrals applied to the angular intensity distribution at the refracting boundaries. The radiative intensity is expressed as the sum of the asymptotic angular intensity distribution valid in the depth of the scattering medium and a transient term valid near the boundary. Integrated boundary equations are obtained, yielding simple linear equations for the intensity coefficients, enabling the angular emission intensity and the diffuse reflectance (albedo) and transmittance of the scattering layer to be calculated without solving the radiative transfer equation directly. Examples are given of half-space, slab, interface, and double-layer calculations, and extensions to multilayer systems are indicated. The K-integral method is orders of magnitude more accurate than diffusion theory and can be applied to layered scattering media with a wide range of scattering albedos, with potential applications to biomedical and ocean optics. PMID:27409700

  18. New law requires 'medically accurate' lesson plans.

    PubMed

    1999-09-17

    The California Legislature has passed a bill requiring all textbooks and materials used to teach about AIDS be medically accurate and objective. Statements made within the curriculum must be supported by research conducted in compliance with scientific methods, and published in peer-reviewed journals. Some of the current lesson plans were found to contain scientifically unsupported and biased information. In addition, the bill requires material to be "free of racial, ethnic, or gender biases." The legislation is supported by a wide range of interests, but opposed by the California Right to Life Education Fund, because they believe it discredits abstinence-only material. PMID:11366835

  19. Soil spectra contributions to grass canopy spectral reflectance

    NASA Technical Reports Server (NTRS)

    Tucker, C. J.; Miller, L. D.

    1977-01-01

    The soil or background spectra contribution to grass canopy spectral reflectance for the 0.35 to 0.80 micron region was investigated using in situ collected spectral reflectance data. Regression analysis was used to estimate accurately the unexposed soil spectral reflectance and to quantify maxima and minima for soil-green vegetation reflection contrasts.

  20. Biology Reflective Assessment Curriculum

    NASA Astrophysics Data System (ADS)

    Bayley, Cheryl Ann

    Often students and educators view assessments as an obligation and finality for a unit. In the current climate of high-stakes testing and accountability, the balance of time, resources and emphasis on students' scores related to assessment have been slanted considerably toward the summative side. This tension between assessment for accountability and assessment to inform teaching strains instruction and educators' ability to use that information to design learning opportunities that help students develop deeper conceptual understanding. A substantive body of research indicates that formative and reflective assessment can significantly improve student learning. Biology Reflective Assessment Curriculum (BRAC) examines support provided for high school science students through assessment practices. This investigation incorporates the usage of reflective assessments as a guiding practice for differentiated instruction and student choice. Reflective assessment is a metacognitive strategy that promotes self-monitoring and evaluation. The goals of the curriculum are to promote self-efficacy and conceptual understanding in students learning biology through developing their metacognitive awareness. BRAC was implemented in a high school biology classroom. Data from assessments, metacognitive surveys, self-efficacy surveys, reflective journals, student work, a culminating task and field notes were used to evaluate the effectiveness of the curriculum. The results suggest that students who develop their metacognitive skills developed a deeper conceptual understanding and improved feelings of self-efficacy when they were engaged in a reflective assessment unit embedded with student choice. BRAC is a tool for teachers to use assessments to assist students in becoming metacognitive and to guide student choice in learning opportunities.

  1. Monitoring circuit accurately measures movement of solenoid valve

    NASA Technical Reports Server (NTRS)

    Gillett, J. D.

    1966-01-01

    Solenoid operated valve in a control system powered by direct current issued to accurately measure the valve travel. This system is currently in operation with a 28-vdc power system used for control of fluids in liquid rocket motor test facilities.

  2. Predict amine solution properties accurately

    SciTech Connect

    Cheng, S.; Meisen, A.; Chakma, A.

    1996-02-01

    Improved process design begins with using accurate physical property data. Especially in the preliminary design stage, physical property data such as density viscosity, thermal conductivity and specific heat can affect the overall performance of absorbers, heat exchangers, reboilers and pump. These properties can also influence temperature profiles in heat transfer equipment and thus control or affect the rate of amine breakdown. Aqueous-amine solution physical property data are available in graphical form. However, it is not convenient to use with computer-based calculations. Developed equations allow improved correlations of derived physical property estimates with published data. Expressions are given which can be used to estimate physical properties of methyldiethanolamine (MDEA), monoethanolamine (MEA) and diglycolamine (DGA) solutions.

  3. Accurate thickness measurement of graphene

    NASA Astrophysics Data System (ADS)

    Shearer, Cameron J.; Slattery, Ashley D.; Stapleton, Andrew J.; Shapter, Joseph G.; Gibson, Christopher T.

    2016-03-01

    Graphene has emerged as a material with a vast variety of applications. The electronic, optical and mechanical properties of graphene are strongly influenced by the number of layers present in a sample. As a result, the dimensional characterization of graphene films is crucial, especially with the continued development of new synthesis methods and applications. A number of techniques exist to determine the thickness of graphene films including optical contrast, Raman scattering and scanning probe microscopy techniques. Atomic force microscopy (AFM), in particular, is used extensively since it provides three-dimensional images that enable the measurement of the lateral dimensions of graphene films as well as the thickness, and by extension the number of layers present. However, in the literature AFM has proven to be inaccurate with a wide range of measured values for single layer graphene thickness reported (between 0.4 and 1.7 nm). This discrepancy has been attributed to tip-surface interactions, image feedback settings and surface chemistry. In this work, we use standard and carbon nanotube modified AFM probes and a relatively new AFM imaging mode known as PeakForce tapping mode to establish a protocol that will allow users to accurately determine the thickness of graphene films. In particular, the error in measuring the first layer is reduced from 0.1-1.3 nm to 0.1-0.3 nm. Furthermore, in the process we establish that the graphene-substrate adsorbate layer and imaging force, in particular the pressure the tip exerts on the surface, are crucial components in the accurate measurement of graphene using AFM. These findings can be applied to other 2D materials.

  4. Accurate upwind methods for the Euler equations

    NASA Technical Reports Server (NTRS)

    Huynh, Hung T.

    1993-01-01

    A new class of piecewise linear methods for the numerical solution of the one-dimensional Euler equations of gas dynamics is presented. These methods are uniformly second-order accurate, and can be considered as extensions of Godunov's scheme. With an appropriate definition of monotonicity preservation for the case of linear convection, it can be shown that they preserve monotonicity. Similar to Van Leer's MUSCL scheme, they consist of two key steps: a reconstruction step followed by an upwind step. For the reconstruction step, a monotonicity constraint that preserves uniform second-order accuracy is introduced. Computational efficiency is enhanced by devising a criterion that detects the 'smooth' part of the data where the constraint is redundant. The concept and coding of the constraint are simplified by the use of the median function. A slope steepening technique, which has no effect at smooth regions and can resolve a contact discontinuity in four cells, is described. As for the upwind step, existing and new methods are applied in a manner slightly different from those in the literature. These methods are derived by approximating the Euler equations via linearization and diagonalization. At a 'smooth' interface, Harten, Lax, and Van Leer's one intermediate state model is employed. A modification for this model that can resolve contact discontinuities is presented. Near a discontinuity, either this modified model or a more accurate one, namely, Roe's flux-difference splitting. is used. The current presentation of Roe's method, via the conceptually simple flux-vector splitting, not only establishes a connection between the two splittings, but also leads to an admissibility correction with no conditional statement, and an efficient approximation to Osher's approximate Riemann solver. These reconstruction and upwind steps result in schemes that are uniformly second-order accurate and economical at smooth regions, and yield high resolution at discontinuities.

  5. A Reflective Look at Reflecting Teams

    ERIC Educational Resources Information Center

    Pender, Rebecca L.; Stinchfield, Tracy

    2012-01-01

    This article reviewed existing literature and research on the reflecting team process. There is a dearth of empirical research that explores the reflecting team process and the outcome of counseling that uses reflecting teams. Implications of using reflecting teams for counselors, counselor educators, and clients will be discussed. A call for…

  6. Fast and accurate propagation of coherent light

    PubMed Central

    Lewis, R. D.; Beylkin, G.; Monzón, L.

    2013-01-01

    We describe a fast algorithm to propagate, for any user-specified accuracy, a time-harmonic electromagnetic field between two parallel planes separated by a linear, isotropic and homogeneous medium. The analytical formulation of this problem (ca 1897) requires the evaluation of the so-called Rayleigh–Sommerfeld integral. If the distance between the planes is small, this integral can be accurately evaluated in the Fourier domain; if the distance is very large, it can be accurately approximated by asymptotic methods. In the large intermediate region of practical interest, where the oscillatory Rayleigh–Sommerfeld kernel must be applied directly, current numerical methods can be highly inaccurate without indicating this fact to the user. In our approach, for any user-specified accuracy ϵ>0, we approximate the kernel by a short sum of Gaussians with complex-valued exponents, and then efficiently apply the result to the input data using the unequally spaced fast Fourier transform. The resulting algorithm has computational complexity , where we evaluate the solution on an N×N grid of output points given an M×M grid of input samples. Our algorithm maintains its accuracy throughout the computational domain. PMID:24204184

  7. Accurate ab Initio Spin Densities

    PubMed Central

    2012-01-01

    We present an approach for the calculation of spin density distributions for molecules that require very large active spaces for a qualitatively correct description of their electronic structure. Our approach is based on the density-matrix renormalization group (DMRG) algorithm to calculate the spin density matrix elements as a basic quantity for the spatially resolved spin density distribution. The spin density matrix elements are directly determined from the second-quantized elementary operators optimized by the DMRG algorithm. As an analytic convergence criterion for the spin density distribution, we employ our recently developed sampling-reconstruction scheme [J. Chem. Phys.2011, 134, 224101] to build an accurate complete-active-space configuration-interaction (CASCI) wave function from the optimized matrix product states. The spin density matrix elements can then also be determined as an expectation value employing the reconstructed wave function expansion. Furthermore, the explicit reconstruction of a CASCI-type wave function provides insight into chemically interesting features of the molecule under study such as the distribution of α and β electrons in terms of Slater determinants, CI coefficients, and natural orbitals. The methodology is applied to an iron nitrosyl complex which we have identified as a challenging system for standard approaches [J. Chem. Theory Comput.2011, 7, 2740]. PMID:22707921

  8. Reflected Ceiling Plan/Reflected Deck Plan 2009; Reflected Ceiling Plan/Reflected Deck ...

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

    Reflected Ceiling Plan/Reflected Deck Plan 2009; Reflected Ceiling Plan/Reflected Deck Plan 2010 - Gilpin's Falls Covered Bridge, Spanning North East Creek at Former (Bypassed) Section of North East Road (SR 272), North East, Cecil County, MD

  9. Toward Accurate and Quantitative Comparative Metagenomics.

    PubMed

    Nayfach, Stephen; Pollard, Katherine S

    2016-08-25

    Shotgun metagenomics and computational analysis are used to compare the taxonomic and functional profiles of microbial communities. Leveraging this approach to understand roles of microbes in human biology and other environments requires quantitative data summaries whose values are comparable across samples and studies. Comparability is currently hampered by the use of abundance statistics that do not estimate a meaningful parameter of the microbial community and biases introduced by experimental protocols and data-cleaning approaches. Addressing these challenges, along with improving study design, data access, metadata standardization, and analysis tools, will enable accurate comparative metagenomics. We envision a future in which microbiome studies are replicable and new metagenomes are easily and rapidly integrated with existing data. Only then can the potential of metagenomics for predictive ecological modeling, well-powered association studies, and effective microbiome medicine be fully realized. PMID:27565341

  10. Characterization of Multilayer Reflective Coatings for Extreme Ultraviolet Lithography

    SciTech Connect

    Wedowski, M.; Gullikson, E.M.; Underwood, J.H.; Spiller, E.A.; Montcalm, C.; Kearney, P.A.; Bajt, S.; Schmidt, M.A.; Folta, J.A.

    1999-11-01

    The synchrotron-based reflectometer at beamline 6.3.2 of the Advanced Light Source (ALS) in Berkeley is an important metrology tool within the current Extreme Ultraviolet Lithography (EUVL) program. This program is a joint activity of three National Laboratories and a consortium of leading semiconductor manufacturers. Its goal is the development of a technology for routine production of sub-100 nm feature sizes for microelectronic circuits. Multilayer-coated normal-incidence optical surfaces reflecting in the Extreme Ultraviolet (EUV) spectral range near 13 nm are the basis for this emerging technology. All optical components of EUV lithographic steppers need to be characterized at-wavelength during their development and manufacturing process. Multilayer coating uniformity and gradient, accurate wavelength matching and high peak reflectances are the main parameters to be optimized. The mechanical and optical properties of the reflectometer at ALS beamline 6.3.2 proved to be well suited for the needs of the current EUVL program. In particular the facility is highly precise in its wavelength calibration and the determination of absolute EUV reflectance. The reproducibility of results of measurements at ALS beamline 6.3.2 is 0.2 % for reflectivity and 0.002 nm for wavelength.

  11. Retrieval of surface BRDF for reflectance-based calibration

    NASA Astrophysics Data System (ADS)

    Thome, K.; Czapla-Myers, J.; McCorkel, J.

    2007-09-01

    The University of Arizona has recently deployed a set of automated, downlooking radiometers to retrieve surface reflectance of the Railroad Valley test site in Nevada. Results from these radiometers have been combined with atmospheric data from the same site to provide a reflectance-based, vicarious calibration of multiple sensors. The accuracy of the calibrations is similar to those obtained from on-site personnel. Past work has emphasized near-nadir views by the satellite sensors under study to match more closely the view geometry of the automated radiometers to minimize the effect of bi-directional effects in the surface reflectance. Extension to off-nadir views requires an accurate understanding of the surface BRDF. Surface bi-directional reflectance effects have always played a key role in the accuracy of the vicarious calibration of imaging sensors. Such effects are especially important for the large, off-nadir views of sensors such as AVHRR and MODIS. The current work presents a method for retrieving the BRDF using the nadir-viewing data from the automated radiometers throughout the day. The concept of reciprocity is used to derive the reflectance as a function of view angle based on the measurements as a function of solar zenith angle. Comparisons of the results from this approach are compared to MODIS-derived BRDF data as well as ground-based measurements.

  12. Reflections on Rodent Implantation.

    PubMed

    Cha, Jeeyeon M; Dey, Sudhansu K

    2015-01-01

    Embryo implantation is a complex process involving endocrine, paracrine, autocrine, and juxtacrine modulators that span cell-cell and cell-matrix interactions. The quality of implantation is predictive for pregnancy success. Earlier observational studies formed the basis for genetic and molecular approaches that ensued with emerging technological advances. However, the precise sequence and details of the molecular interactions involved have yet to be defined. This review reflects briefly on aspects of our current understanding of rodent implantation as a tribute to Roger Short's lifelong contributions to the field of reproductive physiology. PMID:26450495

  13. Broad-band acoustic Doppler current profiler

    USGS Publications Warehouse

    Cobb, E.D.

    1993-01-01

    The broad-band acoustic Doppler current profiler is an instrument that determines velocity based on the Doppler principle by reflecting acoustic signals off sediment particles in the water. The instrument is capable of measuring velocity magnitude and direction throughout a water column and of measuring water depth. It is also capable of bottom tracking and can, therefore, keep track of its own relative position as it is moved across a channel. Discharge measurements can be made quickly and, based on limited tests, accurately with this instrument. ?? 1993.

  14. Occurrence and Magnitude of High Reflectance Materials on the Moon

    NASA Astrophysics Data System (ADS)

    Nuno, R. G.; Boyd, A. K.; Robinson, M. S.

    2013-12-01

    We utilize a Lunar Reconnaissance Orbiter (LRO) Wide Angle Camera (WAC) 643 nm photometrically normalized (30°, 0°, 30°; i, e, g) reflectance map to investigate the occurrence and origin of high reflectance materials on the Moon. Compositional differences (mainly iron and titanium content) and maturity state (e.g. Copernican crater rays and swirls) are the predominant factors affecting reflectance variations observed on the Moon. Therefore, comparing reflectance values of different regions yields insight into the composition and relative exposure age of lunar materials. But an accurate comparison requires precise reflectance values normalized across every region being investigated. The WAC [1] obtains monthly near-global ground coverage, each month's observations acquired with different lighting conditions. Boyd et al. [2] utilized a geologically homogeneous subset [0°N to 90°N, 146°E to 148°E] of the WAC observations to determine an equation that describes how viewing and lighting angles affect reflectance values. A normalized global reflectance map was generated by applying the local empirical solution globally, with photometric angles derived from the WAC Global Lunar Digital Terrain Model (DTM)(GLD100) [3]. The GLD100 enables accurate correction of reflectance differences caused by local topographic undulations at the scale of 300 meters. We compare reflectance values across the Moon within 80°S to 80°N latitude. The features with the highest reflectance are steep crater walls within Copernican aged craters, such as the walls of Giordano Bruno, which have normalized reflectance values up to 0.35. Near-impact ejecta of some craters have high reflectance values, such as Virtanen (0.22). There are also broad relatively flat features with high reflectance, such as the 900-km Thales-Compton region (0.24) and the 600-km extent of Anaxagoras (Copernican age) ejecta (0.20). Since the interior of Anaxagoras contains occurrences of pure anorthosite [4], the high

  15. Accurate Inventories Of Irrigated Land

    NASA Technical Reports Server (NTRS)

    Wall, S.; Thomas, R.; Brown, C.

    1992-01-01

    System for taking land-use inventories overcomes two problems in estimating extent of irrigated land: only small portion of large state surveyed in given year, and aerial photographs made on 1 day out of year do not provide adequate picture of areas growing more than one crop per year. Developed for state of California as guide to controlling, protecting, conserving, and distributing water within state. Adapted to any large area in which large amounts of irrigation water needed for agriculture. Combination of satellite images, aerial photography, and ground surveys yields data for computer analysis. Analyst also consults agricultural statistics, current farm reports, weather reports, and maps. These information sources aid in interpreting patterns, colors, textures, and shapes on Landsat-images.

  16. Planar Reflection of Gaseous Detonations

    NASA Astrophysics Data System (ADS)

    Damazo, Jason Scott

    Pipes containing flammable gaseous mixtures may be subjected to internal detonation. When the detonation normally impinges on a closed end, a reflected shock wave is created to bring the flow back to rest. This study built on the work of Karnesky (2010) and examined deformation of thin-walled stainless steel tubes subjected to internal reflected gaseous detonations. A ripple pattern was observed in the tube wall for certain fill pressures, and a criterion was developed that predicted when the ripple pattern would form. A two-dimensional finite element analysis was performed using Johnson-Cook material properties; the pressure loading created by reflected gaseous detonations was accounted for with a previously developed pressure model. The residual plastic strain between experiments and computations was in good agreement. During the examination of detonation-driven deformation, discrepancies were discovered in our understanding of reflected gaseous detonation behavior. Previous models did not accurately describe the nature of the reflected shock wave, which motivated further experiments in a detonation tube with optical access. Pressure sensors and schlieren images were used to examine reflected shock behavior, and it was determined that the discrepancies were related to the reaction zone thickness extant behind the detonation front. During these experiments reflected shock bifurcation did not appear to occur, but the unfocused visualization system made certainty impossible. This prompted construction of a focused schlieren system that investigated possible shock wave-boundary layer interaction, and heat-flux gauges analyzed the boundary layer behind the detonation front. Using these data with an analytical boundary layer solution, it was determined that the strong thermal boundary layer present behind the detonation front inhibits the development of reflected shock wave bifurcation.

  17. Challenging Narcissus, or Reflecting on Reflecting.

    ERIC Educational Resources Information Center

    Achilles, C. M.

    The concept of reflective practice and teaching people to be reflective practitioners is examined. The document begins with a look at professional knowledge according to three prominent professionals in the educational administration field: Schon, Schein, and Achilles. "Reflective" strategies that could be incorporated into courses and seminars,…

  18. 38 CFR 4.46 - Accurate measurement.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 38 Pensions, Bonuses, and Veterans' Relief 1 2013-07-01 2013-07-01 false Accurate measurement. 4... RATING DISABILITIES Disability Ratings The Musculoskeletal System § 4.46 Accurate measurement. Accurate measurement of the length of stumps, excursion of joints, dimensions and location of scars with respect...

  19. 38 CFR 4.46 - Accurate measurement.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 38 Pensions, Bonuses, and Veterans' Relief 1 2010-07-01 2010-07-01 false Accurate measurement. 4... RATING DISABILITIES Disability Ratings The Musculoskeletal System § 4.46 Accurate measurement. Accurate measurement of the length of stumps, excursion of joints, dimensions and location of scars with respect...

  20. 38 CFR 4.46 - Accurate measurement.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 38 Pensions, Bonuses, and Veterans' Relief 1 2011-07-01 2011-07-01 false Accurate measurement. 4... RATING DISABILITIES Disability Ratings The Musculoskeletal System § 4.46 Accurate measurement. Accurate measurement of the length of stumps, excursion of joints, dimensions and location of scars with respect...

  1. 38 CFR 4.46 - Accurate measurement.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 38 Pensions, Bonuses, and Veterans' Relief 1 2014-07-01 2014-07-01 false Accurate measurement. 4... RATING DISABILITIES Disability Ratings The Musculoskeletal System § 4.46 Accurate measurement. Accurate measurement of the length of stumps, excursion of joints, dimensions and location of scars with respect...

  2. 38 CFR 4.46 - Accurate measurement.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 38 Pensions, Bonuses, and Veterans' Relief 1 2012-07-01 2012-07-01 false Accurate measurement. 4... RATING DISABILITIES Disability Ratings The Musculoskeletal System § 4.46 Accurate measurement. Accurate measurement of the length of stumps, excursion of joints, dimensions and location of scars with respect...

  3. Detecting Cancer Quickly and Accurately

    NASA Astrophysics Data System (ADS)

    Gourley, Paul; McDonald, Anthony; Hendricks, Judy; Copeland, Guild; Hunter, John; Akhil, Ohmar; Capps, Heather; Curry, Marc; Skirboll, Steve

    2000-03-01

    We present a new technique for high throughput screening of tumor cells in a sensitive nanodevice that has the potential to quickly identify a cell population that has begun the rapid protein synthesis and mitosis characteristic of cancer cell proliferation. Currently, pathologists rely on microscopic examination of cell morphology using century-old staining methods that are labor-intensive, time-consuming and frequently in error. New micro-analytical methods for automated, real time screening without chemical modification are critically needed to advance pathology and improve diagnoses. We have teamed scientists with physicians to create a microlaser biochip (based upon our R&D award winning bio-laser concept)1 which evaluates tumor cells by quantifying their growth kinetics. The key new discovery was demonstrating that the lasing spectra are sensitive to the biomolecular mass in the cell, which changes the speed of light in the laser microcavity. Initial results with normal and cancerous human brain cells show that only a few hundred cells -- the equivalent of a billionth of a liter -- are required to detect abnormal growth. The ability to detect cancer in such a minute tissue sample is crucial for resecting a tumor margin or grading highly localized tumor malignancy. 1. P. L. Gourley, NanoLasers, Scientific American, March 1998, pp. 56-61. This work supported under DOE contract DE-AC04-94AL85000 and the Office of Basic Energy Sciences.

  4. Detecting cancer quickly and accurately

    NASA Astrophysics Data System (ADS)

    Gourley, Paul L.; McDonald, Anthony E.; Hendricks, Judy K.; Copeland, G. C.; Hunter, John A.; Akhil, O.; Cheung, D.; Cox, Jimmy D.; Capps, H.; Curry, Mark S.; Skirboll, Steven K.

    2000-03-01

    We present a new technique for high throughput screening of tumor cells in a sensitive nanodevice that has the potential to quickly identify a cell population that has begun the rapid protein synthesis and mitosis characteristic of cancer cell proliferation. Currently, pathologists rely on microscopic examination of cell morphology using century-old staining methods that are labor-intensive, time-consuming and frequently in error. New micro-analytical methods for automated, real time screening without chemical modification are critically needed to advance pathology and improve diagnoses. We have teamed scientists with physicians to create a microlaser biochip (based upon our R&D award winning bio- laser concept) which evaluates tumor cells by quantifying their growth kinetics. The key new discovery was demonstrating that the lasing spectra are sensitive to the biomolecular mass in the cell, which changes the speed of light in the laser microcavity. Initial results with normal and cancerous human brain cells show that only a few hundred cells -- the equivalent of a billionth of a liter -- are required to detect abnormal growth. The ability to detect cancer in such a minute tissue sample is crucial for resecting a tumor margin or grading highly localized tumor malignancy.

  5. The importance of accurate atmospheric modeling

    NASA Astrophysics Data System (ADS)

    Payne, Dylan; Schroeder, John; Liang, Pang

    2014-11-01

    This paper will focus on the effect of atmospheric conditions on EO sensor performance using computer models. We have shown the importance of accurately modeling atmospheric effects for predicting the performance of an EO sensor. A simple example will demonstrated how real conditions for several sites in China will significantly impact on image correction, hyperspectral imaging, and remote sensing. The current state-of-the-art model for computing atmospheric transmission and radiance is, MODTRAN® 5, developed by the US Air Force Research Laboratory and Spectral Science, Inc. Research by the US Air Force, Navy and Army resulted in the public release of LOWTRAN 2 in the early 1970's. Subsequent releases of LOWTRAN and MODTRAN® have continued until the present. Please verify that (1) all pages are present, (2) all figures are correct, (3) all fonts and special characters are correct, and (4) all text and figures fit within the red margin lines shown on this review document. Complete formatting information is available at http://SPIE.org/manuscripts Return to the Manage Active Submissions page at http://spie.org/submissions/tasks.aspx and approve or disapprove this submission. Your manuscript will not be published without this approval. Please contact author_help@spie.org with any questions or concerns. The paper will demonstrate the importance of using validated models and local measured meteorological, atmospheric and aerosol conditions to accurately simulate the atmospheric transmission and radiance. Frequently default conditions are used which can produce errors of as much as 75% in these values. This can have significant impact on remote sensing applications.

  6. How flatbed scanners upset accurate film dosimetry.

    PubMed

    van Battum, L J; Huizenga, H; Verdaasdonk, R M; Heukelom, S

    2016-01-21

    Film is an excellent dosimeter for verification of dose distributions due to its high spatial resolution. Irradiated film can be digitized with low-cost, transmission, flatbed scanners. However, a disadvantage is their lateral scan effect (LSE): a scanner readout change over its lateral scan axis. Although anisotropic light scattering was presented as the origin of the LSE, this paper presents an alternative cause. Hereto, LSE for two flatbed scanners (Epson 1680 Expression Pro and Epson 10000XL), and Gafchromic film (EBT, EBT2, EBT3) was investigated, focused on three effects: cross talk, optical path length and polarization. Cross talk was examined using triangular sheets of various optical densities. The optical path length effect was studied using absorptive and reflective neutral density filters with well-defined optical characteristics (OD range 0.2-2.0). Linear polarizer sheets were used to investigate light polarization on the CCD signal in absence and presence of (un)irradiated Gafchromic film. Film dose values ranged between 0.2 to 9 Gy, i.e. an optical density range between 0.25 to 1.1. Measurements were performed in the scanner's transmission mode, with red-green-blue channels. LSE was found to depend on scanner construction and film type. Its magnitude depends on dose: for 9 Gy increasing up to 14% at maximum lateral position. Cross talk was only significant in high contrast regions, up to 2% for very small fields. The optical path length effect introduced by film on the scanner causes 3% for pixels in the extreme lateral position. Light polarization due to film and the scanner's optical mirror system is the main contributor, different in magnitude for the red, green and blue channel. We concluded that any Gafchromic EBT type film scanned with a flatbed scanner will face these optical effects. Accurate dosimetry requires correction of LSE, therefore, determination of the LSE per color channel and dose delivered to the film. PMID:26689962

  7. How flatbed scanners upset accurate film dosimetry

    NASA Astrophysics Data System (ADS)

    van Battum, L. J.; Huizenga, H.; Verdaasdonk, R. M.; Heukelom, S.

    2016-01-01

    Film is an excellent dosimeter for verification of dose distributions due to its high spatial resolution. Irradiated film can be digitized with low-cost, transmission, flatbed scanners. However, a disadvantage is their lateral scan effect (LSE): a scanner readout change over its lateral scan axis. Although anisotropic light scattering was presented as the origin of the LSE, this paper presents an alternative cause. Hereto, LSE for two flatbed scanners (Epson 1680 Expression Pro and Epson 10000XL), and Gafchromic film (EBT, EBT2, EBT3) was investigated, focused on three effects: cross talk, optical path length and polarization. Cross talk was examined using triangular sheets of various optical densities. The optical path length effect was studied using absorptive and reflective neutral density filters with well-defined optical characteristics (OD range 0.2-2.0). Linear polarizer sheets were used to investigate light polarization on the CCD signal in absence and presence of (un)irradiated Gafchromic film. Film dose values ranged between 0.2 to 9 Gy, i.e. an optical density range between 0.25 to 1.1. Measurements were performed in the scanner’s transmission mode, with red-green-blue channels. LSE was found to depend on scanner construction and film type. Its magnitude depends on dose: for 9 Gy increasing up to 14% at maximum lateral position. Cross talk was only significant in high contrast regions, up to 2% for very small fields. The optical path length effect introduced by film on the scanner causes 3% for pixels in the extreme lateral position. Light polarization due to film and the scanner’s optical mirror system is the main contributor, different in magnitude for the red, green and blue channel. We concluded that any Gafchromic EBT type film scanned with a flatbed scanner will face these optical effects. Accurate dosimetry requires correction of LSE, therefore, determination of the LSE per color channel and dose delivered to the film.

  8. Reflectance spectra of subarctic lichens

    NASA Technical Reports Server (NTRS)

    Petzold, Donald E.; Goward, Samuel N.

    1988-01-01

    Lichens constitute a major portion of the ground cover of high latitude environments, but little has been reported concerning their in situ solar spectral reflectance properties. Knowledge of these properties is important for the interpretation of remotely sensed observations from high latitude regions, as well as in studies of high latitude ecology and energy balance climatology. The spectral reflectance of common boreal vascular plants is similar to that of vascular plants of the midlatitudes. The dominant lichens, in contrast, display variable reflectance patterns in visible wavelengths. The relative reflectance peak at 0.55 microns, common to green vegetation, is absent or indistinct in spectra of pervasive boreal forest and tundra lichens, despite the presence of chlorophyll in the inner algal cells. Lichens of the dominant genus, Cladina, display strong absorption of ultraviolet energy and short-wavelength blue light relative to their absorption in other visible wavelengths. Since the Cladinae dominate both the surface vegetation in open woodlands of the boreal forest and the low arctic tundra, their unusual spectral reflectance patterns will enable accurate monitoring of the boreal forest-tundra ecotone and detection of its vigor and movement in the future.

  9. Orientations to Reflective Practice.

    ERIC Educational Resources Information Center

    Wellington, Bud; Austin, Patricia

    1996-01-01

    Delineates five orientations to reflective practice: immediate, technical, deliberative, dialectic, and transpersonal, each reflecting different social science bases and beliefs and values about education. Views them as interactive, interdependent, noncompeting, aspects of reflective practice. (SK)

  10. Accurate Fission Data for Nuclear Safety

    NASA Astrophysics Data System (ADS)

    Solders, A.; Gorelov, D.; Jokinen, A.; Kolhinen, V. S.; Lantz, M.; Mattera, A.; Penttilä, H.; Pomp, S.; Rakopoulos, V.; Rinta-Antila, S.

    2014-05-01

    The Accurate fission data for nuclear safety (AlFONS) project aims at high precision measurements of fission yields, using the renewed IGISOL mass separator facility in combination with a new high current light ion cyclotron at the University of Jyväskylä. The 30 MeV proton beam will be used to create fast and thermal neutron spectra for the study of neutron induced fission yields. Thanks to a series of mass separating elements, culminating with the JYFLTRAP Penning trap, it is possible to achieve a mass resolving power in the order of a few hundred thousands. In this paper we present the experimental setup and the design of a neutron converter target for IGISOL. The goal is to have a flexible design. For studies of exotic nuclei far from stability a high neutron flux (1012 neutrons/s) at energies 1 - 30 MeV is desired while for reactor applications neutron spectra that resembles those of thermal and fast nuclear reactors are preferred. It is also desirable to be able to produce (semi-)monoenergetic neutrons for benchmarking and to study the energy dependence of fission yields. The scientific program is extensive and is planed to start in 2013 with a measurement of isomeric yield ratios of proton induced fission in uranium. This will be followed by studies of independent yields of thermal and fast neutron induced fission of various actinides.

  11. Questioning Intuition through Reflective Engagement

    ERIC Educational Resources Information Center

    Schmidt, Christopher D.

    2014-01-01

    Current literature on ethics and moral development focuses on discussion concerning the impact of intuition on moral decision-making. Through the use of student journal reflections over the course of one semester, this study utilized a grounded theory approach in order to explore and understand participant levels of awareness and understanding of…

  12. Teaching Student Teachers to Reflect.

    ERIC Educational Resources Information Center

    Zeichner, Kenneth M.; Liston, Daniel P.

    1987-01-01

    The authors argue that the current teacher education program model, featuring apprenticeship, inhibits the self-directed growth of student teachers and fails to promote their full professional development. They describe an alternative model used at the University of Wisconsin, Madison, that promotes reflective teaching, teacher autonomy, and…

  13. Quantitative Hyperspectral Reflectance Imaging

    PubMed Central

    Klein, Marvin E.; Aalderink, Bernard J.; Padoan, Roberto; de Bruin, Gerrit; Steemers, Ted A.G.

    2008-01-01

    Hyperspectral imaging is a non-destructive optical analysis technique that can for instance be used to obtain information from cultural heritage objects unavailable with conventional colour or multi-spectral photography. This technique can be used to distinguish and recognize materials, to enhance the visibility of faint or obscured features, to detect signs of degradation and study the effect of environmental conditions on the object. We describe the basic concept, working principles, construction and performance of a laboratory instrument specifically developed for the analysis of historical documents. The instrument measures calibrated spectral reflectance images at 70 wavelengths ranging from 365 to 1100 nm (near-ultraviolet, visible and near-infrared). By using a wavelength tunable narrow-bandwidth light-source, the light energy used to illuminate the measured object is minimal, so that any light-induced degradation can be excluded. Basic analysis of the hyperspectral data includes a qualitative comparison of the spectral images and the extraction of quantitative data such as mean spectral reflectance curves and statistical information from user-defined regions-of-interest. More sophisticated mathematical feature extraction and classification techniques can be used to map areas on the document, where different types of ink had been applied or where one ink shows various degrees of degradation. The developed quantitative hyperspectral imager is currently in use by the Nationaal Archief (National Archives of The Netherlands) to study degradation effects of artificial samples and original documents, exposed in their permanent exhibition area or stored in their deposit rooms.

  14. Benefits of Reflective Practice

    ERIC Educational Resources Information Center

    Wagner, Kathi

    2006-01-01

    In this article, the author discusses what she was able to learn from an exercise in self-reflection regarding her teaching. She also discusses the advantages of reflection for administrators: First, a reflective practice is data-driven, making it a more valid way to evaluate administrators' knowledge and skills. Second, a reflective practice…

  15. Telescope With Reflecting Baffle

    NASA Technical Reports Server (NTRS)

    Linlor, W. I.

    1985-01-01

    Telescope baffle made from combination of reflecting surfaces. In contrast with previous ellipsoidal reflecting baffles, new baffle reflects skew rays more effectively and easier to construct. For infrared telescopes, reflecting baffles better than absorbing baffles because heat load reduced, and not necessary to contend with insufficiency of infrared absorption exhibited by black coatings.

  16. Light Field Imaging Based Accurate Image Specular Highlight Removal

    PubMed Central

    Wang, Haoqian; Xu, Chenxue; Wang, Xingzheng; Zhang, Yongbing; Peng, Bo

    2016-01-01

    Specular reflection removal is indispensable to many computer vision tasks. However, most existing methods fail or degrade in complex real scenarios for their individual drawbacks. Benefiting from the light field imaging technology, this paper proposes a novel and accurate approach to remove specularity and improve image quality. We first capture images with specularity by the light field camera (Lytro ILLUM). After accurately estimating the image depth, a simple and concise threshold strategy is adopted to cluster the specular pixels into “unsaturated” and “saturated” category. Finally, a color variance analysis of multiple views and a local color refinement are individually conducted on the two categories to recover diffuse color information. Experimental evaluation by comparison with existed methods based on our light field dataset together with Stanford light field archive verifies the effectiveness of our proposed algorithm. PMID:27253083

  17. Simulating Scintillator Light Collection Using Measured Optical Reflectance

    SciTech Connect

    Janecek, Martin; Moses, William

    2010-01-28

    To accurately predict the light collection from a scintillating crystal through Monte Carlo simulations, it is crucial to know the angular distribution from the surface reflectance. Current Monte Carlo codes allow the user to set the optical reflectance to a linear combination of backscatter spike, specular spike, specular lobe, and Lambertian reflections. However, not all light distributions can be expressed in this way. In addition, the user seldom has the detailed knowledge about the surfaces that is required for accurate modeling. We have previously measured the angular distributions within BGO crystals and now incorporate these data as look-up-tables (LUTs) into modified Geant4 and GATE Monte Carlo codes. The modified codes allow the user to specify the surface treatment (ground, etched, or polished), the attached reflector (Lumirror(R), Teflon(R), ESR film, Tyvek(R), or TiO paint), and the bonding type (air-coupled or glued). Each LUT consists of measured angular distributions with 4o by 5o resolution in theta and phi, respectively, for incidence angles from 0? to 90? degrees, in 1o-steps. We compared the new codes to the original codes by running simulations with a 3 x 10 x 30 mm3 BGO crystal coupled to a PMT. The simulations were then compared to measurements. Light output was measured by counting the photons detected by the PMT with the 3 x 10, 3 x 30, or 10 x 30 mm2 side coupled to the PMT, respectively. Our new code shows better agreement with the measured data than the current Geant4 code. The new code can also simulate reflector materials that are not pure specular or Lambertian reflectors, as was previously required. Our code is also more user friendly, as no detailed knowledge about the surfaces or light distributions is required from the user.

  18. Scintillator reflective layer coextrusion

    SciTech Connect

    Yun, Jae-Chul; Para, Adam

    2001-01-01

    A polymeric scintillator has a reflective layer adhered to the exterior surface thereof. The reflective layer comprises a reflective pigment and an adhesive binder. The adhesive binder includes polymeric material from which the scintillator is formed. A method of forming the polymeric scintillator having a reflective layer adhered to the exterior surface thereof is also provided. The method includes the steps of (a) extruding an inner core member from a first amount of polymeric scintillator material, and (b) coextruding an outer reflective layer on the exterior surface of the inner core member. The outer reflective layer comprises a reflective pigment and a second amount of the polymeric scintillator material.

  19. Identification of Terrestrial Reflectance From Remote Sensing

    NASA Technical Reports Server (NTRS)

    Alter-Gartenberg, Rachel; Nolf, Scott R.; Stacy, Kathryn (Technical Monitor)

    2000-01-01

    Correcting for atmospheric effects is an essential part of surface-reflectance recovery from radiance measurements. Model-based atmospheric correction techniques enable an accurate identification and classification of terrestrial reflectances from multi-spectral imagery. Successful and efficient removal of atmospheric effects from remote-sensing data is a key factor in the success of Earth observation missions. This report assesses the performance, robustness and sensitivity of two atmospheric-correction and reflectance-recovery techniques as part of an end-to-end simulation of hyper-spectral acquisition, identification and classification.

  20. Reflectivity, Reflexivity and Situated Reflective Practice

    ERIC Educational Resources Information Center

    Malthouse, Richard; Roffey-Barentsen, Jodi; Watts, Mike

    2014-01-01

    This paper describes an aspect of reflective practice referred to as situated reflective practice. The overarching theory is derived from social theories of structuration and reflexivity. In particular, from Giddens' theory of structuration, which sees social life as an interplay of agency and structure. Discussion of the research reported…

  1. MODIS solar reflective calibration traceability

    NASA Astrophysics Data System (ADS)

    Xiong, Xiaoxiong; Butler, Jim

    2009-08-01

    Long-term climate data records often consist of observations made by multiple sensors. It is, therefore, extremely important to have instrument overlap, to be able to track instrument stability, to quantify measurement uncertainties, and to establish an absolute measurement scale traceable to the International System of Units (SI). The Moderate Resolution Imaging Spectroradiometer (MODIS) is a key instrument for both the Terra and Aqua missions, which were launched in December 1999 and May 2002, respectively. It has 20 reflective solar bands (RSB) with wavelengths from 0.41 to 2.2μm and observes the Earth at three nadir spatial resolutions: 0.25km, 0.5km, and 1km. MODIS RSB on-orbit calibration is reflectance based with reference to the bi-directional reflectance factor (BRF) of its on-board solar diffuser (SD). The SD BRF characterization was made pre-launch by the instrument vendor using reference samples traceable directly to the National Institute of Standards and Technology (NIST). On-orbit SD reflectance degradation is tracked by an on-board solar diffuser stability monitor (SDSM). This paper provides details of this calibration chain, from pre-launch to on-orbit operation, and associated uncertainty assessments. Using MODIS as an example, this paper also discusses challenges and key design requirements for future missions developed for accurate climate studies.

  2. MODIS Solar Reflective Calibration Traceability

    NASA Technical Reports Server (NTRS)

    Xiong, Xiaoxiong; Butler, Jim

    2009-01-01

    Long-term climate data records often consist of observations made by multiple sensors. It is, therefore, extremely important to have instrument overlap, to be able to track instrument stability, to quantify, measurement uncertainties, and to establish absolute scale traceable to the International System of Units (SI). The Moderate Resolution Imaging Spectroradiometer (MODIS) is a key instrument for both the Terra and Aqua missions, which were launched in December 1999 and May 2002, respectively. It has 20 reflective solar bands (RSB) with wavelengths from 0.41 to 2.2 micrometers and observes the Earth at three nadir spatial resolutions: 0.25km, 0.5km, and 1km. MODIS RSB on-orbit calibration is reflectance based with reference to the bidirectional reflectance factor (BRF) of its on-board solar diffuser (SD). The SD BRF characterization was made pre-launch by the instrument vendor using reference samples traceable directly to the National Institute of Standards and Technology (NIST). On-orbit SD reflectance degradation is tracked by an on-board solar diffuser monitor (SDSM). This paper provides details of this calibration chain, from prelaunch to on-orbit operation, and associated uncertainty assessments. Using MODIS as an example, this paper also discusses challenges and key design requirements for future missions developed for accurate climate studies.

  3. Inter-reflection Compensation of Immersive Projection Display by Spatio-Temporal Screen Reflectance Modulation.

    PubMed

    Takeda, Shoichi; Iwai, Daisuke; Sato, Kosuke

    2016-04-01

    We propose a novel inter-reflection compensation technique for immersive projection displays wherein we spatially modulate the reflectance pattern on the screen to improve the compensation performance of conventional methods. As the luminance of light reflected on a projection surface is mathematically represented as the multiplication of the illuminance of incident light and the surface reflectance, we can reduce undesirable intensity elevation because of inter-reflections by decreasing surface reflectance. Based on this principle, we improve conventional inter-reflection compensation techniques by applying reflectance pattern modulation. We realize spatial reflectance modulation of a projection screen by painting it with a photochromic compound, which changes its color (i.e., the reflectance of the screen) when ultraviolet (UV) light is applied and by controlling UV irradiation with a UV LED array placed behind the screen. The main contribution of this paper is a computational model to optimize a reflectance pattern for the accurate reproduction of a target appearance by decreasing the intensity elevation caused by inter-reflection while maintaining the maximum intensity of the target appearance. Through simulation and physical experiments, we demonstrate the feasibility of the proposed model and confirm its advantage over conventional methods. PMID:26780805

  4. Tunable reflection minima of nanostructured antireflective surfaces

    NASA Astrophysics Data System (ADS)

    Boden, S. A.; Bagnall, D. M.

    2008-09-01

    Broadband antireflection schemes for silicon surfaces based on the moth-eye principle and comprising arrays of subwavelength-scale pillars are applicable to solar cells, photodetectors, and stealth technologies and can exhibit very low reflectances. We show that rigorous coupled wave analysis can be used to accurately model the intricate reflectance behavior of these surfaces and so can be used to explore the effects of variations in pillar height, period, and shape. Low reflectance regions are identified, the extent of which are determined by the shape of the pillars. The wavelengths over which these low reflectance regions operate can be shifted by altering the period of the array. Thus the subtle features of the reflectance spectrum of a moth-eye array can be tailored for optimum performance for the input spectrum of a specific application.

  5. Understanding reflective practice.

    PubMed

    Nicol, Jacqueline Sian; Dosser, Isabel

    2016-05-01

    The Nursing and Midwifery Council (NMC) requires that nurses and midwives use feedback as an opportunity for reflection and learning, to improve practice. The NMC revalidation process stipulates that practitioners provide examples of how they have achieved this. To reflect in a meaningful way, it is important to understand what is meant by reflection, the skills required, and how reflection can be undertaken successfully. Traditionally, reflection occurs after an event encountered in practice. The authors challenge this perception, suggesting that reflection should be undertaken before, during and after an event. This article provides practical guidance to help practitioners use reflective models to write reflective accounts. It also outlines how the reflective process can be used as a valuable learning tool in preparation for revalidation. PMID:27154119

  6. Accurate orbit propagation with planetary close encounters

    NASA Astrophysics Data System (ADS)

    Baù, Giulio; Milani Comparetti, Andrea; Guerra, Francesca

    2015-08-01

    We tackle the problem of accurately propagating the motion of those small bodies that undergo close approaches with a planet. The literature is lacking on this topic and the reliability of the numerical results is not sufficiently discussed. The high-frequency components of the perturbation generated by a close encounter makes the propagation particularly challenging both from the point of view of the dynamical stability of the formulation and the numerical stability of the integrator. In our approach a fixed step-size and order multistep integrator is combined with a regularized formulation of the perturbed two-body problem. When the propagated object enters the region of influence of a celestial body, the latter becomes the new primary body of attraction. Moreover, the formulation and the step-size will also be changed if necessary. We present: 1) the restarter procedure applied to the multistep integrator whenever the primary body is changed; 2) new analytical formulae for setting the step-size (given the order of the multistep, formulation and initial osculating orbit) in order to control the accumulation of the local truncation error and guarantee the numerical stability during the propagation; 3) a new definition of the region of influence in the phase space. We test the propagator with some real asteroids subject to the gravitational attraction of the planets, the Yarkovsky and relativistic perturbations. Our goal is to show that the proposed approach improves the performance of both the propagator implemented in the OrbFit software package (which is currently used by the NEODyS service) and of the propagator represented by a variable step-size and order multistep method combined with Cowell's formulation (i.e. direct integration of position and velocity in either the physical or a fictitious time).

  7. Accurate paleointensities - the multi-method approach

    NASA Astrophysics Data System (ADS)

    de Groot, Lennart

    2016-04-01

    The accuracy of models describing rapid changes in the geomagnetic field over the past millennia critically depends on the availability of reliable paleointensity estimates. Over the past decade methods to derive paleointensities from lavas (the only recorder of the geomagnetic field that is available all over the globe and through geologic times) have seen significant improvements and various alternative techniques were proposed. The 'classical' Thellier-style approach was optimized and selection criteria were defined in the 'Standard Paleointensity Definitions' (Paterson et al, 2014). The Multispecimen approach was validated and the importance of additional tests and criteria to assess Multispecimen results must be emphasized. Recently, a non-heating, relative paleointensity technique was proposed -the pseudo-Thellier protocol- which shows great potential in both accuracy and efficiency, but currently lacks a solid theoretical underpinning. Here I present work using all three of the aforementioned paleointensity methods on suites of young lavas taken from the volcanic islands of Hawaii, La Palma, Gran Canaria, Tenerife, and Terceira. Many of the sampled cooling units are <100 years old, the actual field strength at the time of cooling is therefore reasonably well known. Rather intuitively, flows that produce coherent results from two or more different paleointensity methods yield the most accurate estimates of the paleofield. Furthermore, the results for some flows pass the selection criteria for one method, but fail in other techniques. Scrutinizing and combing all acceptable results yielded reliable paleointensity estimates for 60-70% of all sampled cooling units - an exceptionally high success rate. This 'multi-method paleointensity approach' therefore has high potential to provide the much-needed paleointensities to improve geomagnetic field models for the Holocene.

  8. Editorial Commentary: Reflections From a Mature Arthroscopic Shoulder Surgeon on the History and Current Benefits of Augmentation for the Revision of a Massive Rotator Cuff Tear Using Acellular Human Dermal Matrix Allograft.

    PubMed

    Snyder, Stephen J

    2016-09-01

    Acellular human dermal matrix allografts are now being used to augment and sometimes replace severely damaged rotator cuff tissue. I have been interested in this important aspect of orthopaedics for 15 years and am pleased to have the opportunity to share my personal reflections of some of the highlights in science and the literature that helped get to the point now where we can expect greater than 80% healing even in these difficult cases of revision after massive failed cuff repair. The field of tissue engineering will certainly be a critical part of our rotator cuff surgical future. PMID:27594327

  9. Blogging for Reflection: The Use of Online Journals to Engage Students in Reflective Learning

    ERIC Educational Resources Information Center

    Muncy, James A.

    2014-01-01

    Reflective learning has long been studied in many disciplines. A primary way that reflective learning has been taught is through journaling. With the advent of e-learning, journaling has moved to the Web in the form of blogs. The current paper reviews the current state of journaling and blogging research with specific recommendations for marketing…

  10. Nonexposure accurate location K-anonymity algorithm in LBS.

    PubMed

    Jia, Jinying; Zhang, Fengli

    2014-01-01

    This paper tackles location privacy protection in current location-based services (LBS) where mobile users have to report their exact location information to an LBS provider in order to obtain their desired services. Location cloaking has been proposed and well studied to protect user privacy. It blurs the user's accurate coordinate and replaces it with a well-shaped cloaked region. However, to obtain such an anonymous spatial region (ASR), nearly all existent cloaking algorithms require knowing the accurate locations of all users. Therefore, location cloaking without exposing the user's accurate location to any party is urgently needed. In this paper, we present such two nonexposure accurate location cloaking algorithms. They are designed for K-anonymity, and cloaking is performed based on the identifications (IDs) of the grid areas which were reported by all the users, instead of directly on their accurate coordinates. Experimental results show that our algorithms are more secure than the existent cloaking algorithms, need not have all the users reporting their locations all the time, and can generate smaller ASR. PMID:24605060

  11. Nonexposure Accurate Location K-Anonymity Algorithm in LBS

    PubMed Central

    2014-01-01

    This paper tackles location privacy protection in current location-based services (LBS) where mobile users have to report their exact location information to an LBS provider in order to obtain their desired services. Location cloaking has been proposed and well studied to protect user privacy. It blurs the user's accurate coordinate and replaces it with a well-shaped cloaked region. However, to obtain such an anonymous spatial region (ASR), nearly all existent cloaking algorithms require knowing the accurate locations of all users. Therefore, location cloaking without exposing the user's accurate location to any party is urgently needed. In this paper, we present such two nonexposure accurate location cloaking algorithms. They are designed for K-anonymity, and cloaking is performed based on the identifications (IDs) of the grid areas which were reported by all the users, instead of directly on their accurate coordinates. Experimental results show that our algorithms are more secure than the existent cloaking algorithms, need not have all the users reporting their locations all the time, and can generate smaller ASR. PMID:24605060

  12. Reflections in art

    PubMed Central

    CAVANAGH, PATRICK; CHAO, JESSICA; WANG, DINA

    2009-01-01

    When artists depict a mirror in a painting, it necessarily lacks the most obvious property of a mirror: as we move around the painting of the mirror, the reflections we see in it do not change. And yet representations of mirrors and other reflecting surfaces can be quite convincing in paintings. Here, we will examine the rules of reflection, the many ways that painters can break those rules without losing the impression of reflection and the rules that cannot be broken. The rules that govern the perception of reflection are a small subset of the physical rules of reflection. PMID:18534102

  13. DCP-collected absolute target reflectance signatures assist accurate interpretation of ERTS-1 imagery

    NASA Technical Reports Server (NTRS)

    Weber, F. P.

    1973-01-01

    Data collection platforms (DCP's) are being used at a Black Hills, South Dakota, test site (MMC 226A) to record radiometric measurements needed to determine solar and atmospheric parameters that affect ERTS-1 multispectral scanner radiance measurements. A total of 72 channels of analog data transmitted from an unattended ground truth site via three DCP's at least six times a day. The system has operated with only minor problems since September, sending forth daily measurements of biophysical responses and atmospheric conditions. Comparisons of scene radiance data calculated from ERTS images with that measured on the ground show the image-measured values to be 35 percent higher for the green channel and 20 percent higher for the red channel for the same scene targets. Radiance values for channels 6 and 7 are nearly the same from the ground data and from the imagery.

  14. How Can We Identify Replies that Accurately Reflect Students' Knowledge? A Methodological Proposal. Research Report

    ERIC Educational Resources Information Center

    Marin, N.; Gomez, E. Jimenez; Benarroch, A.

    2004-01-01

    The catalogue of conceptions that students are said to have concerning the different topics of the science curriculum is so great that some authors consider this line of research to be exhausted. However, others insist on the need to re-examine students' conceptions in order to better describe them using new theoretical, contexts and research…

  15. Mill profiler machines soft materials accurately

    NASA Technical Reports Server (NTRS)

    Rauschl, J. A.

    1966-01-01

    Mill profiler machines bevels, slots, and grooves in soft materials, such as styrofoam phenolic-filled cores, to any desired thickness. A single operator can accurately control cutting depths in contour or straight line work.

  16. Remote balance weighs accurately amid high radiation

    NASA Technical Reports Server (NTRS)

    Eggenberger, D. N.; Shuck, A. B.

    1969-01-01

    Commercial beam-type balance, modified and outfitted with electronic controls and digital readout, can be remotely controlled for use in high radiation environments. This allows accurate weighing of breeder-reactor fuel pieces when they are radioactively hot.

  17. Neutron reflecting supermirror structure

    DOEpatents

    Wood, James L.

    1992-01-01

    An improved neutron reflecting supermirror structure comprising a plurality of stacked sets of bilayers of neutron reflecting materials. The improved neutron reflecting supermirror structure is adapted to provide extremely good performance at high incidence angles, i.e. up to four time the critical angle of standard neutron mirror structures. The reflection of neutrons striking the supermirror structure at a high critical angle provides enhanced neutron throughput, and hence more efficient and economical use of neutron sources.

  18. Neutron reflecting supermirror structure

    DOEpatents

    Wood, J.L.

    1992-12-01

    An improved neutron reflecting supermirror structure comprising a plurality of stacked sets of bilayers of neutron reflecting materials. The improved neutron reflecting supermirror structure is adapted to provide extremely good performance at high incidence angles, i.e. up to four time the critical angle of standard neutron mirror structures. The reflection of neutrons striking the supermirror structure at a high critical angle provides enhanced neutron throughput, and hence more efficient and economical use of neutron sources. 2 figs.

  19. Building the Reflective Capacity of Practicing Principals

    ERIC Educational Resources Information Center

    Rich, Robert A.; Jackson, Sherion H.

    2006-01-01

    Reflection is often used as a professional development tool in coaching and mentoring leaders. Outside of education, research is underway to learn how managers can develop as learning facilitators in the workplace. However, the current focus on learning communities and learning organizations within education makes reflective thinking particularly…

  20. A Reflective Conversation with James H. Borland

    ERIC Educational Resources Information Center

    Shaughnessy, Michael F.; Moore, Tammy-Lynne; Borland, James H.

    2014-01-01

    James H. Borland, Ph.D. is Professor of Education in the Department of Curriculum and Teaching at Teachers College, Columbia University in New York City. In this reflective conversation, he reflects on his experiences in an urban environment and the current challenges in gifted education. He argues for ongoing diagnosis of learners' needs…

  1. Understanding the Code: keeping accurate records.

    PubMed

    Griffith, Richard

    2015-10-01

    In his continuing series looking at the legal and professional implications of the Nursing and Midwifery Council's revised Code of Conduct, Richard Griffith discusses the elements of accurate record keeping under Standard 10 of the Code. This article considers the importance of accurate record keeping for the safety of patients and protection of district nurses. The legal implications of records are explained along with how district nurses should write records to ensure these legal requirements are met. PMID:26418404

  2. Reflective Learning in Practice.

    ERIC Educational Resources Information Center

    Brockbank, Anne, Ed.; McGill, Ian, Ed.; Beech, Nic, Ed.

    This book contains 22 papers on reflective learning in practice. The following papers are included: "Our Purpose" (Ann Brockbank, Ian McGill, Nic Beech); "The Nature and Context of Learning" (Ann Brockbank, Ian McGill, Nic Beech); "Reflective Learning and Organizations" (Ann Brockbank, Ian McGill, Nic Beech); "Reflective Learning in Practice" (Ann…

  3. Liberating Moral Reflection

    ERIC Educational Resources Information Center

    Horell, Harold D.

    2013-01-01

    The author argues that if we are to foster life-giving and liberating moral reflection, we must first liberate moral reflection from distortions; specifically, from the distorting effects of moral insensitivity, destructive moral relativism, and confusions resulting from a failure to understand the dynamics of moral reflection. The author proposes…

  4. Teaching Critical Reflection

    ERIC Educational Resources Information Center

    Smith, Elizabeth

    2011-01-01

    Despite long-standing commitment to the notion of critical reflection across the healthcare professions it is unusual for critical theory and practice to be taught as explicit subjects in healthcare higher education. There is evidence to show that reflective techniques such as critical portfolios and reflective diaries can help students to…

  5. Revalidation and reflective practice.

    PubMed

    Finch, Alison

    2016-04-01

    From April 2016 nurses must meet the requirements of the new Nursing and Midwifery Council (NMC) revalidation process to maintain their registration. It is their responsibility to ensure they meet all revalidation requirements, but organisations and nurse leaders can support them to do so. Reflection is an important part of revalidation, and nurses are required to submit written reflective accounts and engage in reflective discussion. This article discusses how revalidation encourages a more conscious and active form of reflection. It also describes how leaders can help nurses to reflect on practice to identify improvements and become more familiar with the NMC Code. PMID:27032284

  6. Accurate theoretical chemistry with coupled pair models.

    PubMed

    Neese, Frank; Hansen, Andreas; Wennmohs, Frank; Grimme, Stefan

    2009-05-19

    Quantum chemistry has found its way into the everyday work of many experimental chemists. Calculations can predict the outcome of chemical reactions, afford insight into reaction mechanisms, and be used to interpret structure and bonding in molecules. Thus, contemporary theory offers tremendous opportunities in experimental chemical research. However, even with present-day computers and algorithms, we cannot solve the many particle Schrodinger equation exactly; inevitably some error is introduced in approximating the solutions of this equation. Thus, the accuracy of quantum chemical calculations is of critical importance. The affordable accuracy depends on molecular size and particularly on the total number of atoms: for orientation, ethanol has 9 atoms, aspirin 21 atoms, morphine 40 atoms, sildenafil 63 atoms, paclitaxel 113 atoms, insulin nearly 800 atoms, and quaternary hemoglobin almost 12,000 atoms. Currently, molecules with up to approximately 10 atoms can be very accurately studied by coupled cluster (CC) theory, approximately 100 atoms with second-order Møller-Plesset perturbation theory (MP2), approximately 1000 atoms with density functional theory (DFT), and beyond that number with semiempirical quantum chemistry and force-field methods. The overwhelming majority of present-day calculations in the 100-atom range use DFT. Although these methods have been very successful in quantum chemistry, they do not offer a well-defined hierarchy of calculations that allows one to systematically converge to the correct answer. Recently a number of rather spectacular failures of DFT methods have been found-even for seemingly simple systems such as hydrocarbons, fueling renewed interest in wave function-based methods that incorporate the relevant physics of electron correlation in a more systematic way. Thus, it would be highly desirable to fill the gap between 10 and 100 atoms with highly correlated ab initio methods. We have found that one of the earliest (and now

  7. Remotely Sensing the Photochemical Reflectance Index (PRI)

    NASA Technical Reports Server (NTRS)

    Vanderbilt, Vern

    2015-01-01

    In remote sensing, the Photochemical Reflectance Index (PRI) provides insight into physiological processes occurring inside the leaves in a stand of plants. Developed by Gamon et al., (1990 and 1992), PRI evolved from laboratory measurements of the reflectance of individual leaves (Bilger et al.,1989). Yet in a remotely sensed image, a pixel measurement may include light from both reflecting and transmitting leaves. We conducted laboratory experiments comparing values of PRI based upon polarized reflectance and transmittance measurements of water and nutrient stressed leaves. We illuminated single detached leaves using a current controlled light source (Oriel model 66881) and measured the leaf weight using an analytical balance (Mettler model AE 260) and the light reflected and transmitted by the leaf during dry down using two Analytical Spectral Devices spectroradiometers. Polarizers on the incident and reflected light beams allowed us to divide the leaf reflectance into two parts: a polarized surface reflectance and a non-polarized 'leaf interior' reflectance. Our results underscore the importance when calculating PRI of removing the leaf surface reflection, which contains no information about physiological processes ongoing in the leaf interior. The results show that the leaf physiology information is in the leaf interior reflectance, not the leaf transmittance. Applied to a plant stand, these results suggest use of polarization measurements in sun-view directions that minimize the number of sunlit transmitting leaves in the sensor field of view.

  8. A robust and accurate formulation of molecular and colloidal electrostatics.

    PubMed

    Sun, Qiang; Klaseboer, Evert; Chan, Derek Y C

    2016-08-01

    This paper presents a re-formulation of the boundary integral method for the Debye-Hückel model of molecular and colloidal electrostatics that removes the mathematical singularities that have to date been accepted as an intrinsic part of the conventional boundary integral equation method. The essence of the present boundary regularized integral equation formulation consists of subtracting a known solution from the conventional boundary integral method in such a way as to cancel out the singularities associated with the Green's function. This approach better reflects the non-singular physical behavior of the systems on boundaries with the benefits of the following: (i) the surface integrals can be evaluated accurately using quadrature without any need to devise special numerical integration procedures, (ii) being able to use quadratic or spline function surface elements to represent the surface more accurately and the variation of the functions within each element is represented to a consistent level of precision by appropriate interpolation functions, (iii) being able to calculate electric fields, even at boundaries, accurately and directly from the potential without having to solve hypersingular integral equations and this imparts high precision in calculating the Maxwell stress tensor and consequently, intermolecular or colloidal forces, (iv) a reliable way to handle geometric configurations in which different parts of the boundary can be very close together without being affected by numerical instabilities, therefore potentials, fields, and forces between surfaces can be found accurately at surface separations down to near contact, and (v) having the simplicity of a formulation that does not require complex algorithms to handle singularities will result in significant savings in coding effort and in the reduction of opportunities for coding errors. These advantages are illustrated using examples drawn from molecular and colloidal electrostatics. PMID:27497538

  9. A robust and accurate formulation of molecular and colloidal electrostatics

    NASA Astrophysics Data System (ADS)

    Sun, Qiang; Klaseboer, Evert; Chan, Derek Y. C.

    2016-08-01

    This paper presents a re-formulation of the boundary integral method for the Debye-Hückel model of molecular and colloidal electrostatics that removes the mathematical singularities that have to date been accepted as an intrinsic part of the conventional boundary integral equation method. The essence of the present boundary regularized integral equation formulation consists of subtracting a known solution from the conventional boundary integral method in such a way as to cancel out the singularities associated with the Green's function. This approach better reflects the non-singular physical behavior of the systems on boundaries with the benefits of the following: (i) the surface integrals can be evaluated accurately using quadrature without any need to devise special numerical integration procedures, (ii) being able to use quadratic or spline function surface elements to represent the surface more accurately and the variation of the functions within each element is represented to a consistent level of precision by appropriate interpolation functions, (iii) being able to calculate electric fields, even at boundaries, accurately and directly from the potential without having to solve hypersingular integral equations and this imparts high precision in calculating the Maxwell stress tensor and consequently, intermolecular or colloidal forces, (iv) a reliable way to handle geometric configurations in which different parts of the boundary can be very close together without being affected by numerical instabilities, therefore potentials, fields, and forces between surfaces can be found accurately at surface separations down to near contact, and (v) having the simplicity of a formulation that does not require complex algorithms to handle singularities will result in significant savings in coding effort and in the reduction of opportunities for coding errors. These advantages are illustrated using examples drawn from molecular and colloidal electrostatics.

  10. Reflective Fourier ptychography

    NASA Astrophysics Data System (ADS)

    Pacheco, Shaun; Zheng, Guoan; Liang, Rongguang

    2016-02-01

    The Fourier ptychography technique in reflection mode has great potential applications in tissue imaging and optical inspection, but the current configuration either has a limitation on cut-off frequency or is not practical. By placing the imaging aperture stop outside the illumination path, the illumination numerical aperture (NA) can be greater than the imaging NA of the objective lens. Thus, the cut-off frequency achieved in the proposed optical system is greater than twice the objective's NA divided by the wavelength (2NAobj/λ), which is the diffraction limit for the cut-off frequency in an incoherent epi-illumination configuration. We experimentally demonstrated that the synthesized NA is increased by a factor of 4.5 using the proposed optical concept. The key advantage of the proposed system is that it can achieve high-resolution imaging over a large field of view with a simple objective. It will have a great potential for applications in endoscopy, biomedical imaging, surface metrology, and industrial inspection.

  11. Reflective Fourier ptychography.

    PubMed

    Pacheco, Shaun; Zheng, Guoan; Liang, Rongguang

    2016-02-01

    The Fourier ptychography technique in reflection mode has great potential applications in tissue imaging and optical inspection, but the current configuration either has a limitation on cut-off frequency or is not practical. By placing the imaging aperture stop outside the illumination path, the illumination numerical aperture (NA) can be greater than the imaging NA of the objective lens. Thus, the cut-off frequency achieved in the proposed optical system is greater than twice the objective's NA divided by the wavelength (2NAobj/λ ), which is the diffraction limit for the cut-off frequency in an incoherent epi-illumination configuration. We experimentally demonstrated that the synthesized NA is increased by a factor of 4.5 using the proposed optical concept. The key advantage of the proposed system is that it can achieve high-resolution imaging over a large field of view with a simple objective. It will have a great potential for applications in endoscopy, biomedical imaging, surface metrology, and industrial inspection. PMID:26891601

  12. Benchmarking accurate spectral phase retrieval of single attosecond pulses

    NASA Astrophysics Data System (ADS)

    Wei, Hui; Le, Anh-Thu; Morishita, Toru; Yu, Chao; Lin, C. D.

    2015-02-01

    A single extreme-ultraviolet (XUV) attosecond pulse or pulse train in the time domain is fully characterized if its spectral amplitude and phase are both determined. The spectral amplitude can be easily obtained from photoionization of simple atoms where accurate photoionization cross sections have been measured from, e.g., synchrotron radiations. To determine the spectral phase, at present the standard method is to carry out XUV photoionization in the presence of a dressing infrared (IR) laser. In this work, we examine the accuracy of current phase retrieval methods (PROOF and iPROOF) where the dressing IR is relatively weak such that photoelectron spectra can be accurately calculated by second-order perturbation theory. We suggest a modified method named swPROOF (scattering wave phase retrieval by omega oscillation filtering) which utilizes accurate one-photon and two-photon dipole transition matrix elements and removes the approximations made in PROOF and iPROOF. We show that the swPROOF method can in general retrieve accurate spectral phase compared to other simpler models that have been suggested. We benchmark the accuracy of these phase retrieval methods through simulating the spectrogram by solving the time-dependent Schrödinger equation numerically using several known single attosecond pulses with a fixed spectral amplitude but different spectral phases.

  13. A highly accurate interatomic potential for argon

    NASA Astrophysics Data System (ADS)

    Aziz, Ronald A.

    1993-09-01

    A modified potential based on the individually damped model of Douketis, Scoles, Marchetti, Zen, and Thakkar [J. Chem. Phys. 76, 3057 (1982)] is presented which fits, within experimental error, the accurate ultraviolet (UV) vibration-rotation spectrum of argon determined by UV laser absorption spectroscopy by Herman, LaRocque, and Stoicheff [J. Chem. Phys. 89, 4535 (1988)]. Other literature potentials fail to do so. The potential also is shown to predict a large number of other properties and is probably the most accurate characterization of the argon interaction constructed to date.

  14. RF current sensor

    DOEpatents

    Moore, James A.; Sparks, Dennis O.

    1998-11-10

    An RF sensor having a novel current sensing probe and a voltage sensing probe to measure voltage and current. The current sensor is disposed in a transmission line to link all of the flux generated by the flowing current in order to obtain an accurate measurement. The voltage sensor is a flat plate which operates as a capacitive plate to sense voltage on a center conductor of the transmission line, in which the measured voltage is obtained across a resistance leg of a R-C differentiator circuit formed by the characteristic impedance of a connecting transmission line and a capacitance of the plate, which is positioned proximal to the center conductor.

  15. Photovoltaic module with light reflecting backskin

    DOEpatents

    Gonsiorawski, Ronald C.

    2007-07-03

    A photovoltaic module comprises electrically interconnected and mutually spaced photovoltaic cells that are encapsulated by a light-transmitting encapsulant between a light-transparent front cover and a back cover, with the back cover sheet being an ionomer/nylon alloy embossed with V-shaped grooves running in at least two directions and coated with a light reflecting medium so as to provide light-reflecting facets that are aligned with the spaces between adjacent cells and oriented so as to reflect light falling in those spaces back toward said transparent front cover for further internal reflection onto the solar cells, whereby substantially all of the reflected light will be internally reflected from said cover sheet back to the photovoltaic cells, thereby increasing the current output of the module. The internal reflector improves power output by as much as 67%.

  16. Reflective diffraction grating

    DOEpatents

    Lamartine, Bruce C.

    2003-06-24

    Reflective diffraction grating. A focused ion beam (FIB) micromilling apparatus is used to store color images in a durable medium by milling away portions of the surface of the medium to produce a reflective diffraction grating with blazed pits. The images are retrieved by exposing the surface of the grating to polychromatic light from a particular incident bearing and observing the light reflected by the surface from specified reception bearing.

  17. Tandem resonator reflectance modulator

    DOEpatents

    Fritz, Ian J.; Wendt, Joel R.

    1994-01-01

    A wide band optical modulator is grown on a substrate as tandem Fabry-Perot resonators including three mirrors spaced by two cavities. The absorption of one cavity is changed relative to the absorption of the other cavity by an applied electric field, to cause a change in total reflected light, as light reflecting from the outer mirrors is in phase and light reflecting from the inner mirror is out of phase with light from the outer mirrors.

  18. Tandem resonator reflectance modulator

    DOEpatents

    Fritz, I.J.; Wendt, J.R.

    1994-09-06

    A wide band optical modulator is grown on a substrate as tandem Fabry-Perot resonators including three mirrors spaced by two cavities. The absorption of one cavity is changed relative to the absorption of the other cavity by an applied electric field, to cause a change in total reflected light, as light reflecting from the outer mirrors is in phase and light reflecting from the inner mirror is out of phase with light from the outer mirrors. 8 figs.

  19. Neutron reflecting supermirror structure

    DOEpatents

    Wood, James L.

    1992-01-01

    An improved neutron reflecting supermirror structure comprising a plurality of stacked sets of bilayers of neutron reflecting materials. The improved neutron reflecting supermirror structure is adapted to provide extremely good performance at high incidence angles, i.e. up to four time the critical angle of standard neutron mirror structures. The reflection of neutrons striking the supermirror structure at a high critical angle provides enhanced neutron throughput, and hence more efficient and economical use of neutron sources. One layer of each set of bilayers consist of titanium, and the second layer of each set of bilayers consist of an alloy of nickel with carbon interstitially present in the nickel alloy.

  20. Accurate pointing of tungsten welding electrodes

    NASA Technical Reports Server (NTRS)

    Ziegelmeier, P.

    1971-01-01

    Thoriated-tungsten is pointed accurately and quickly by using sodium nitrite. Point produced is smooth and no effort is necessary to hold the tungsten rod concentric. The chemically produced point can be used several times longer than ground points. This method reduces time and cost of preparing tungsten electrodes.

  1. Reflectance model for acetowhite epithelium

    NASA Astrophysics Data System (ADS)

    Zonios, George

    2012-08-01

    Application of low concentration acetic acid solution to various types of human epithelia, in vivo, is a well-established technique for the visual identification of neoplastic and potential precancerous lesions, especially in the cervix. An acetic acid application produces a transient whitening effect associated with the aforementioned lesions (acetowhite effect). In this article, a simple semi-empirical tissue reflectance model is presented, which describes the acetowhite effect in terms of the tissue's optical properties and layered structure. The model successfully describes data available in the literature, explains basic characteristics of the acetowhite effect, and can serve as the basis for the development of more accurate and reliable noninvasive diagnostic methodologies for precancerous epithelial lesions.

  2. On the importance of having accurate data for astrophysical modelling

    NASA Astrophysics Data System (ADS)

    Lique, Francois

    2016-06-01

    The Herschel telescope and the ALMA and NOEMA interferometers have opened new windows of observation for wavelengths ranging from far infrared to sub-millimeter with spatial and spectral resolutions previously unmatched. To make the most of these observations, an accurate knowledge of the physical and chemical processes occurring in the interstellar and circumstellar media is essential.In this presentation, I will discuss what are the current needs of astrophysics in terms of molecular data and I will show that accurate molecular data are crucial for the proper determination of the physical conditions in molecular clouds.First, I will focus on collisional excitation studies that are needed for molecular lines modelling beyond the Local Thermodynamic Equilibrium (LTE) approach. In particular, I will show how new collisional data for the HCN and HNC isomers, two tracers of star forming conditions, have allowed solving the problem of their respective abundance in cold molecular clouds. I will also present the last collisional data that have been computed in order to analyse new highly resolved observations provided by the ALMA interferometer.Then, I will present the calculation of accurate rate constants for the F+H2 → HF+H and Cl+H2 ↔ HCl+H reactions, which have allowed a more accurate determination of the physical conditions in diffuse molecular clouds. I will also present the recent work on the ortho-para-H2 conversion due to hydrogen exchange that allow more accurate determination of the ortho-to-para-H2 ratio in the universe and that imply a significant revision of the cooling mechanism in astrophysical media.

  3. Stereotypes of age differences in personality traits: universal and accurate?

    PubMed

    Chan, Wayne; McCrae, Robert R; De Fruyt, Filip; Jussim, Lee; Löckenhoff, Corinna E; De Bolle, Marleen; Costa, Paul T; Sutin, Angelina R; Realo, Anu; Allik, Jüri; Nakazato, Katsuharu; Shimonaka, Yoshiko; Hřebíčková, Martina; Graf, Sylvie; Yik, Michelle; Brunner-Sciarra, Marina; de Figueora, Nora Leibovich; Schmidt, Vanina; Ahn, Chang-Kyu; Ahn, Hyun-nie; Aguilar-Vafaie, Maria E; Siuta, Jerzy; Szmigielska, Barbara; Cain, Thomas R; Crawford, Jarret T; Mastor, Khairul Anwar; Rolland, Jean-Pierre; Nansubuga, Florence; Miramontez, Daniel R; Benet-Martínez, Veronica; Rossier, Jérôme; Bratko, Denis; Marušić, Iris; Halberstadt, Jamin; Yamaguchi, Mami; Knežević, Goran; Martin, Thomas A; Gheorghiu, Mirona; Smith, Peter B; Barbaranelli, Claudio; Wang, Lei; Shakespeare-Finch, Jane; Lima, Margarida P; Klinkosz, Waldemar; Sekowski, Andrzej; Alcalay, Lidia; Simonetti, Franco; Avdeyeva, Tatyana V; Pramila, V S; Terracciano, Antonio

    2012-12-01

    Age trajectories for personality traits are known to be similar across cultures. To address whether stereotypes of age groups reflect these age-related changes in personality, we asked participants in 26 countries (N = 3,323) to rate typical adolescents, adults, and old persons in their own country. Raters across nations tended to share similar beliefs about different age groups; adolescents were seen as impulsive, rebellious, undisciplined, preferring excitement and novelty, whereas old people were consistently considered lower on impulsivity, activity, antagonism, and Openness. These consensual age group stereotypes correlated strongly with published age differences on the five major dimensions of personality and most of 30 specific traits, using as criteria of accuracy both self-reports and observer ratings, different survey methodologies, and data from up to 50 nations. However, personal stereotypes were considerably less accurate, and consensual stereotypes tended to exaggerate differences across age groups. PMID:23088227

  4. Stereotypes of Age Differences in Personality Traits: Universal and Accurate?

    PubMed Central

    Chan, Wayne; McCrae, Robert R.; De Fruyt, Filip; Jussim, Lee; Löckenhoff, Corinna E.; De Bolle, Marleen; Costa, Paul T.; Sutin, Angelina R.; Realo, Anu; Allik, Jüri; Nakazato, Katsuharu; Shimonaka, Yoshiko; Hřebíčková, Martina; Kourilova, Sylvie; Yik, Michelle; Ficková, Emília; Brunner-Sciarra, Marina; de Figueora, Nora Leibovich; Schmidt, Vanina; Ahn, Chang-kyu; Ahn, Hyun-nie; Aguilar-Vafaie, Maria E.; Siuta, Jerzy; Szmigielska, Barbara; Cain, Thomas R.; Crawford, Jarret T.; Mastor, Khairul Anwar; Rolland, Jean-Pierre; Nansubuga, Florence; Miramontez, Daniel R.; Benet-Martínez, Veronica; Rossier, Jérôme; Bratko, Denis; Halberstadt, Jamin; Yamaguchi, Mami; Knežević, Goran; Martin, Thomas A.; Gheorghiu, Mirona; Smith, Peter B.; Barbaranelli, Claduio; Wang, Lei; Shakespeare-Finch, Jane; Lima, Margarida P.; Klinkosz, Waldemar; Sekowski, Andrzej; Alcalay, Lidia; Simonetti, Franco; Avdeyeva, Tatyana V.; Pramila, V. S.; Terracciano, Antonio

    2012-01-01

    Age trajectories for personality traits are known to be similar across cultures. To address whether stereotypes of age groups reflect these age-related changes in personality, we asked participants in 26 countries (N = 3,323) to rate typical adolescents, adults, and old persons in their own country. Raters across nations tended to share similar beliefs about different age groups; adolescents were seen as impulsive, rebellious, undisciplined, preferring excitement and novelty, whereas old people were consistently considered lower on impulsivity, activity, antagonism, and Openness. These consensual age group stereotypes correlated strongly with published age differences on the five major dimensions of personality and most of 30 specific traits, using as criteria of accuracy both self-reports and observer ratings, different survey methodologies, and data from up to 50 nations. However, personal stereotypes were considerably less accurate, and consensual stereotypes tended to exaggerate differences across age groups. PMID:23088227

  5. Accurate finite difference methods for time-harmonic wave propagation

    NASA Technical Reports Server (NTRS)

    Harari, Isaac; Turkel, Eli

    1994-01-01

    Finite difference methods for solving problems of time-harmonic acoustics are developed and analyzed. Multidimensional inhomogeneous problems with variable, possibly discontinuous, coefficients are considered, accounting for the effects of employing nonuniform grids. A weighted-average representation is less sensitive to transition in wave resolution (due to variable wave numbers or nonuniform grids) than the standard pointwise representation. Further enhancement in method performance is obtained by basing the stencils on generalizations of Pade approximation, or generalized definitions of the derivative, reducing spurious dispersion, anisotropy and reflection, and by improving the representation of source terms. The resulting schemes have fourth-order accurate local truncation error on uniform grids and third order in the nonuniform case. Guidelines for discretization pertaining to grid orientation and resolution are presented.

  6. Neutron supermirrors: an accurate theory for layer thickness computation

    NASA Astrophysics Data System (ADS)

    Bray, Michael

    2001-11-01

    We present a new theory for the computation of Super-Mirror stacks, using accurate formulas derived from the classical optics field. Approximations are introduced into the computation, but at a later stage than existing theories, providing a more rigorous treatment of the problem. The final result is a continuous thickness stack, whose properties can be determined at the outset of the design. We find that the well-known fourth power dependence of number of layers versus maximum angle is (of course) asymptotically correct. We find a formula giving directly the relation between desired reflectance, maximum angle, and number of layers (for a given pair of materials). Note: The author of this article, a classical opticist, has limited knowledge of the Neutron world, and begs forgiveness for any shortcomings, erroneous assumptions and/or misinterpretation of previous authors' work on the subject.

  7. Critically Reflective Leadership

    ERIC Educational Resources Information Center

    Cunningham, Christine L.

    2012-01-01

    Critical Reflective Practice (CRP) has a proven reputation as a method for teacher-researchers in K-12 classrooms, but there have been few published examples of this method being used to document school leaders' work-based practice. This paper outlines adaptations made by the author from an original CRP method to a Critically Reflective Leadership…

  8. Transparencies and Reflections.

    ERIC Educational Resources Information Center

    Hubbard, Guy

    1999-01-01

    Discusses the use of perspective, or showing things as the human eye sees them, when creating reflections and transparencies in works of art. Provides examples of artwork using transparency, reflection, and refraction by M. C. Escher, Richard Estes, and Janet Fish to give students an opportunity to learn about these three art techniques. (CMK)

  9. Earth's Reflection: Albedo

    ERIC Educational Resources Information Center

    Gillette, Brandon; Hamilton, Cheri

    2011-01-01

    When viewing objects of different colors, you might notice that some appear brighter than others. This is because light is reflected differently from various surfaces, depending on their physical properties. The word "albedo" is used to describe how reflective a surface is. The Earth-atmosphere has a combined albedo of about 30%, a number that is…

  10. Engaging in Retrospective Reflection

    ERIC Educational Resources Information Center

    Brevig, Laurey

    2006-01-01

    Reflection is a powerful means to involve readers actively in gaining new insights about texts and themselves as readers. This article relates the story of three fifth-grade girls engaged in metacognitive inquiry within a classroom book club group. The use of exploratory talk and reflection illustrate how the girls constructed meaning and deepened…

  11. Reflecting Random Flights

    NASA Astrophysics Data System (ADS)

    De Gregorio, Alessandro; Orsingher, Enzo

    2015-09-01

    We consider random flights in reflecting on the surface of a sphere with center at the origin and with radius R, where reflection is performed by means of circular inversion. Random flights studied in this paper are motions where the orientation of the deviations are uniformly distributed on the unit-radius sphere . We obtain the explicit probability distributions of the position of the moving particle when the number of changes of direction is fixed and equal to . We show that these distributions involve functions which are solutions of the Euler-Poisson-Darboux equation. The unconditional probability distributions of the reflecting random flights are obtained by suitably randomizing n by means of a fractional-type Poisson process. Random flights reflecting on hyperplanes according to the optical reflection form are considered and the related distributional properties derived.

  12. Feedback about More Accurate versus Less Accurate Trials: Differential Effects on Self-Confidence and Activation

    ERIC Educational Resources Information Center

    Badami, Rokhsareh; VaezMousavi, Mohammad; Wulf, Gabriele; Namazizadeh, Mahdi

    2012-01-01

    One purpose of the present study was to examine whether self-confidence or anxiety would be differentially affected by feedback from more accurate rather than less accurate trials. The second purpose was to determine whether arousal variations (activation) would predict performance. On Day 1, participants performed a golf putting task under one of…

  13. Reflecting on Čerenkov reflections

    NASA Astrophysics Data System (ADS)

    Fargion, D.; Gaug, M.; Oliva, P.

    2008-05-01

    MAGIC, as well as HESS and VERITAS, is a Čerenkov Telescope unveiling γ-ray sources above 60 GeV at vertical within noisy (hadronic) airshowering sky. These telescopes while facing the horizons may reveal rarest blazing UHECR as well as far fluorescence tails of downward PeV-EeV hadronic airshowers. Few of these inclined airshowers blazing on axis are spread by the geomagnetic field into twin spots. These twin flashes and their morphology may tag the UHECR origination site. There is a rich window of such reflecting Čerenkov lights visible by Telescopes on top of Mountains as MAGIC (and partially VERITAS): the reflections from the nearby ground (possibly enhanced by rain or snow, ice white cover), from the Sea and from the cloudy sky; in particular, these cloudy sheets may lay above or below the observer. MAGIC looking downward to the clouds or the snow, may well reveal blazing Moliere disks diffusing Čerenkov spots (few events per night). Because of geomagnetic forces and splitting of the inclined air-shower, one should reveal for the first time (at tens PeV or above) Čerenkov airshowers whose flashes are skimming the MAGIC nearby Sea and opened into twin spots. Their morphology may tag the UHECR origination, its consequent cross-section and composition. Magic telescopes looking upward into cloudy sky may observe very rare up-going UHE Tau, originated by UHE PeVs neutrinos skimming earth, air-showering into sky, reflecting into clouds. In particular Glashow resonant antineutrinos electron hitting into Earth electrons may lead to gauged boson W-, whose decay (inside the Earth) may produce a τ + bar nuτ [3], which later escape and decay in air is producing Čerenkov lights; these flashes may blaze into the clouds above MAGIC as upward dot spots. The Magic energy threshold for such UHE Neutrinos showers rises to PeV values. EeV UHE tau neutrinos by guaranteed GZK UHECR secondaries [6, 16], via the muon-tau flavor mixing, may skim the Earth, produce UHE tau

  14. Feedback about more accurate versus less accurate trials: differential effects on self-confidence and activation.

    PubMed

    Badami, Rokhsareh; VaezMousavi, Mohammad; Wulf, Gabriele; Namazizadeh, Mahdi

    2012-06-01

    One purpose of the present study was to examine whether self-confidence or anxiety would be differentially affected byfeedback from more accurate rather than less accurate trials. The second purpose was to determine whether arousal variations (activation) would predict performance. On day 1, participants performed a golf putting task under one of two conditions: one group received feedback on the most accurate trials, whereas another group received feedback on the least accurate trials. On day 2, participants completed an anxiety questionnaire and performed a retention test. Shin conductance level, as a measure of arousal, was determined. The results indicated that feedback about more accurate trials resulted in more effective learning as well as increased self-confidence. Also, activation was a predictor of performance. PMID:22808705

  15. Accurate Measurement of Organic Solar Cell Efficiency

    SciTech Connect

    Emery, K.; Moriarty, T.

    2008-01-01

    We discuss the measurement and analysis of current vs. voltage (I-V) characteristics of organic and dye-sensitized photovoltaic cells and modules. A brief discussion of the history of photovoltaic efficiency measurements and procedures will be presented. We discuss both the error sources in the measurements and the strategies to minimize their influence. These error sources include the sample area, spectral errors, temperature fluctuations, current and voltage response time, contacting, and degradation during testing. Information that can be extracted from light and dark I-V measurement includes peak power, open-circuit voltage, short-circuit current, series and shunt resistance, diode quality factor, dark current, and photo-current. The quantum efficiency provides information on photo-current nonlinearities, current generation, and recombination mechanisms.

  16. Machine learning of parameters for accurate semiempirical quantum chemical calculations

    DOE PAGESBeta

    Dral, Pavlo O.; von Lilienfeld, O. Anatole; Thiel, Walter

    2015-04-14

    We investigate possible improvements in the accuracy of semiempirical quantum chemistry (SQC) methods through the use of machine learning (ML) models for the parameters. For a given class of compounds, ML techniques require sufficiently large training sets to develop ML models that can be used for adapting SQC parameters to reflect changes in molecular composition and geometry. The ML-SQC approach allows the automatic tuning of SQC parameters for individual molecules, thereby improving the accuracy without deteriorating transferability to molecules with molecular descriptors very different from those in the training set. The performance of this approach is demonstrated for the semiempiricalmore » OM2 method using a set of 6095 constitutional isomers C7H10O2, for which accurate ab initio atomization enthalpies are available. The ML-OM2 results show improved average accuracy and a much reduced error range compared with those of standard OM2 results, with mean absolute errors in atomization enthalpies dropping from 6.3 to 1.7 kcal/mol. They are also found to be superior to the results from specific OM2 reparameterizations (rOM2) for the same set of isomers. The ML-SQC approach thus holds promise for fast and reasonably accurate high-throughput screening of materials and molecules.« less

  17. Machine learning of parameters for accurate semiempirical quantum chemical calculations

    SciTech Connect

    Dral, Pavlo O.; von Lilienfeld, O. Anatole; Thiel, Walter

    2015-04-14

    We investigate possible improvements in the accuracy of semiempirical quantum chemistry (SQC) methods through the use of machine learning (ML) models for the parameters. For a given class of compounds, ML techniques require sufficiently large training sets to develop ML models that can be used for adapting SQC parameters to reflect changes in molecular composition and geometry. The ML-SQC approach allows the automatic tuning of SQC parameters for individual molecules, thereby improving the accuracy without deteriorating transferability to molecules with molecular descriptors very different from those in the training set. The performance of this approach is demonstrated for the semiempirical OM2 method using a set of 6095 constitutional isomers C7H10O2, for which accurate ab initio atomization enthalpies are available. The ML-OM2 results show improved average accuracy and a much reduced error range compared with those of standard OM2 results, with mean absolute errors in atomization enthalpies dropping from 6.3 to 1.7 kcal/mol. They are also found to be superior to the results from specific OM2 reparameterizations (rOM2) for the same set of isomers. The ML-SQC approach thus holds promise for fast and reasonably accurate high-throughput screening of materials and molecules.

  18. Simple and accurate optical height sensor for wafer inspection systems

    NASA Astrophysics Data System (ADS)

    Shimura, Kei; Nakai, Naoya; Taniguchi, Koichi; Itoh, Masahide

    2016-02-01

    An accurate method for measuring the wafer surface height is required for wafer inspection systems to adjust the focus of inspection optics quickly and precisely. A method for projecting a laser spot onto the wafer surface obliquely and for detecting its image displacement using a one-dimensional position-sensitive detector is known, and a variety of methods have been proposed for improving the accuracy by compensating the measurement error due to the surface patterns. We have developed a simple and accurate method in which an image of a reticle with eight slits is projected on the wafer surface and its reflected image is detected using an image sensor. The surface height is calculated by averaging the coordinates of the images of the slits in both the two directions in the captured image. Pattern-related measurement error was reduced by applying the coordinates averaging to the multiple-slit-projection method. Accuracy of better than 0.35 μm was achieved for a patterned wafer at the reference height and ±0.1 mm from the reference height in a simple configuration.

  19. New model accurately predicts reformate composition

    SciTech Connect

    Ancheyta-Juarez, J.; Aguilar-Rodriguez, E. )

    1994-01-31

    Although naphtha reforming is a well-known process, the evolution of catalyst formulation, as well as new trends in gasoline specifications, have led to rapid evolution of the process, including: reactor design, regeneration mode, and operating conditions. Mathematical modeling of the reforming process is an increasingly important tool. It is fundamental to the proper design of new reactors and revamp of existing ones. Modeling can be used to optimize operating conditions, analyze the effects of process variables, and enhance unit performance. Instituto Mexicano del Petroleo has developed a model of the catalytic reforming process that accurately predicts reformate composition at the higher-severity conditions at which new reformers are being designed. The new AA model is more accurate than previous proposals because it takes into account the effects of temperature and pressure on the rate constants of each chemical reaction.

  20. Accurate colorimetric feedback for RGB LED clusters

    NASA Astrophysics Data System (ADS)

    Man, Kwong; Ashdown, Ian

    2006-08-01

    We present an empirical model of LED emission spectra that is applicable to both InGaN and AlInGaP high-flux LEDs, and which accurately predicts their relative spectral power distributions over a wide range of LED junction temperatures. We further demonstrate with laboratory measurements that changes in LED spectral power distribution with temperature can be accurately predicted with first- or second-order equations. This provides the basis for a real-time colorimetric feedback system for RGB LED clusters that can maintain the chromaticity of white light at constant intensity to within +/-0.003 Δuv over a range of 45 degrees Celsius, and to within 0.01 Δuv when dimmed over an intensity range of 10:1.

  1. Accurate mask model for advanced nodes

    NASA Astrophysics Data System (ADS)

    Zine El Abidine, Nacer; Sundermann, Frank; Yesilada, Emek; Ndiaye, El Hadji Omar; Mishra, Kushlendra; Paninjath, Sankaranarayanan; Bork, Ingo; Buck, Peter; Toublan, Olivier; Schanen, Isabelle

    2014-07-01

    Standard OPC models consist of a physical optical model and an empirical resist model. The resist model compensates the optical model imprecision on top of modeling resist development. The optical model imprecision may result from mask topography effects and real mask information including mask ebeam writing and mask process contributions. For advanced technology nodes, significant progress has been made to model mask topography to improve optical model accuracy. However, mask information is difficult to decorrelate from standard OPC model. Our goal is to establish an accurate mask model through a dedicated calibration exercise. In this paper, we present a flow to calibrate an accurate mask enabling its implementation. The study covers the different effects that should be embedded in the mask model as well as the experiment required to model them.

  2. Accurate guitar tuning by cochlear implant musicians.

    PubMed

    Lu, Thomas; Huang, Juan; Zeng, Fan-Gang

    2014-01-01

    Modern cochlear implant (CI) users understand speech but find difficulty in music appreciation due to poor pitch perception. Still, some deaf musicians continue to perform with their CI. Here we show unexpected results that CI musicians can reliably tune a guitar by CI alone and, under controlled conditions, match simultaneously presented tones to <0.5 Hz. One subject had normal contralateral hearing and produced more accurate tuning with CI than his normal ear. To understand these counterintuitive findings, we presented tones sequentially and found that tuning error was larger at ∼ 30 Hz for both subjects. A third subject, a non-musician CI user with normal contralateral hearing, showed similar trends in performance between CI and normal hearing ears but with less precision. This difference, along with electric analysis, showed that accurate tuning was achieved by listening to beats rather than discriminating pitch, effectively turning a spectral task into a temporal discrimination task. PMID:24651081

  3. Two highly accurate methods for pitch calibration

    NASA Astrophysics Data System (ADS)

    Kniel, K.; Härtig, F.; Osawa, S.; Sato, O.

    2009-11-01

    Among profiles, helix and tooth thickness pitch is one of the most important parameters of an involute gear measurement evaluation. In principle, coordinate measuring machines (CMM) and CNC-controlled gear measuring machines as a variant of a CMM are suited for these kinds of gear measurements. Now the Japan National Institute of Advanced Industrial Science and Technology (NMIJ/AIST) and the German national metrology institute the Physikalisch-Technische Bundesanstalt (PTB) have each developed independently highly accurate pitch calibration methods applicable to CMM or gear measuring machines. Both calibration methods are based on the so-called closure technique which allows the separation of the systematic errors of the measurement device and the errors of the gear. For the verification of both calibration methods, NMIJ/AIST and PTB performed measurements on a specially designed pitch artifact. The comparison of the results shows that both methods can be used for highly accurate calibrations of pitch standards.

  4. Accurate modeling of parallel scientific computations

    NASA Technical Reports Server (NTRS)

    Nicol, David M.; Townsend, James C.

    1988-01-01

    Scientific codes are usually parallelized by partitioning a grid among processors. To achieve top performance it is necessary to partition the grid so as to balance workload and minimize communication/synchronization costs. This problem is particularly acute when the grid is irregular, changes over the course of the computation, and is not known until load time. Critical mapping and remapping decisions rest on the ability to accurately predict performance, given a description of a grid and its partition. This paper discusses one approach to this problem, and illustrates its use on a one-dimensional fluids code. The models constructed are shown to be accurate, and are used to find optimal remapping schedules.

  5. Accurate Guitar Tuning by Cochlear Implant Musicians

    PubMed Central

    Lu, Thomas; Huang, Juan; Zeng, Fan-Gang

    2014-01-01

    Modern cochlear implant (CI) users understand speech but find difficulty in music appreciation due to poor pitch perception. Still, some deaf musicians continue to perform with their CI. Here we show unexpected results that CI musicians can reliably tune a guitar by CI alone and, under controlled conditions, match simultaneously presented tones to <0.5 Hz. One subject had normal contralateral hearing and produced more accurate tuning with CI than his normal ear. To understand these counterintuitive findings, we presented tones sequentially and found that tuning error was larger at ∼30 Hz for both subjects. A third subject, a non-musician CI user with normal contralateral hearing, showed similar trends in performance between CI and normal hearing ears but with less precision. This difference, along with electric analysis, showed that accurate tuning was achieved by listening to beats rather than discriminating pitch, effectively turning a spectral task into a temporal discrimination task. PMID:24651081

  6. Disambiguating past events: Accurate source memory for time and context depends on different retrieval processes.

    PubMed

    Persson, Bjorn M; Ainge, James A; O'Connor, Akira R

    2016-07-01

    Current animal models of episodic memory are usually based on demonstrating integrated memory for what happened, where it happened, and when an event took place. These models aim to capture the testable features of the definition of human episodic memory which stresses the temporal component of the memory as a unique piece of source information that allows us to disambiguate one memory from another. Recently though, it has been suggested that a more accurate model of human episodic memory would include contextual rather than temporal source information, as humans' memory for time is relatively poor. Here, two experiments were carried out investigating human memory for temporal and contextual source information, along with the underlying dual process retrieval processes, using an immersive virtual environment paired with a 'Remember-Know' memory task. Experiment 1 (n=28) showed that contextual information could only be retrieved accurately using recollection, while temporal information could be retrieved using either recollection or familiarity. Experiment 2 (n=24), which used a more difficult task, resulting in reduced item recognition rates and therefore less potential for contamination by ceiling effects, replicated the pattern of results from Experiment 1. Dual process theory predicts that it should only be possible to retrieve source context from an event using recollection, and our results are consistent with this prediction. That temporal information can be retrieved using familiarity alone suggests that it may be incorrect to view temporal context as analogous to other typically used source contexts. This latter finding supports the alternative proposal that time since presentation may simply be reflected in the strength of memory trace at retrieval - a measure ideally suited to trace strength interrogation using familiarity, as is typically conceptualised within the dual process framework. PMID:27174312

  7. An accurate registration technique for distorted images

    NASA Technical Reports Server (NTRS)

    Delapena, Michele; Shaw, Richard A.; Linde, Peter; Dravins, Dainis

    1990-01-01

    Accurate registration of International Ultraviolet Explorer (IUE) images is crucial because the variability of the geometrical distortions that are introduced by the SEC-Vidicon cameras ensures that raw science images are never perfectly aligned with the Intensity Transfer Functions (ITFs) (i.e., graded floodlamp exposures that are used to linearize and normalize the camera response). A technique for precisely registering IUE images which uses a cross correlation of the fixed pattern that exists in all raw IUE images is described.

  8. Accurate maser positions for MALT-45

    NASA Astrophysics Data System (ADS)

    Jordan, Christopher; Bains, Indra; Voronkov, Maxim; Lo, Nadia; Jones, Paul; Muller, Erik; Cunningham, Maria; Burton, Michael; Brooks, Kate; Green, James; Fuller, Gary; Barnes, Peter; Ellingsen, Simon; Urquhart, James; Morgan, Larry; Rowell, Gavin; Walsh, Andrew; Loenen, Edo; Baan, Willem; Hill, Tracey; Purcell, Cormac; Breen, Shari; Peretto, Nicolas; Jackson, James; Lowe, Vicki; Longmore, Steven

    2013-10-01

    MALT-45 is an untargeted survey, mapping the Galactic plane in CS (1-0), Class I methanol masers, SiO masers and thermal emission, and high frequency continuum emission. After obtaining images from the survey, a number of masers were detected, but without accurate positions. This project seeks to resolve each maser and its environment, with the ultimate goal of placing the Class I methanol maser into a timeline of high mass star formation.

  9. Accurate phase-shift velocimetry in rock.

    PubMed

    Shukla, Matsyendra Nath; Vallatos, Antoine; Phoenix, Vernon R; Holmes, William M

    2016-06-01

    Spatially resolved Pulsed Field Gradient (PFG) velocimetry techniques can provide precious information concerning flow through opaque systems, including rocks. This velocimetry data is used to enhance flow models in a wide range of systems, from oil behaviour in reservoir rocks to contaminant transport in aquifers. Phase-shift velocimetry is the fastest way to produce velocity maps but critical issues have been reported when studying flow through rocks and porous media, leading to inaccurate results. Combining PFG measurements for flow through Bentheimer sandstone with simulations, we demonstrate that asymmetries in the molecular displacement distributions within each voxel are the main source of phase-shift velocimetry errors. We show that when flow-related average molecular displacements are negligible compared to self-diffusion ones, symmetric displacement distributions can be obtained while phase measurement noise is minimised. We elaborate a complete method for the production of accurate phase-shift velocimetry maps in rocks and low porosity media and demonstrate its validity for a range of flow rates. This development of accurate phase-shift velocimetry now enables more rapid and accurate velocity analysis, potentially helping to inform both industrial applications and theoretical models. PMID:27111139

  10. Accurate Molecular Polarizabilities Based on Continuum Electrostatics

    PubMed Central

    Truchon, Jean-François; Nicholls, Anthony; Iftimie, Radu I.; Roux, Benoît; Bayly, Christopher I.

    2013-01-01

    A novel approach for representing the intramolecular polarizability as a continuum dielectric is introduced to account for molecular electronic polarization. It is shown, using a finite-difference solution to the Poisson equation, that the Electronic Polarization from Internal Continuum (EPIC) model yields accurate gas-phase molecular polarizability tensors for a test set of 98 challenging molecules composed of heteroaromatics, alkanes and diatomics. The electronic polarization originates from a high intramolecular dielectric that produces polarizabilities consistent with B3LYP/aug-cc-pVTZ and experimental values when surrounded by vacuum dielectric. In contrast to other approaches to model electronic polarization, this simple model avoids the polarizability catastrophe and accurately calculates molecular anisotropy with the use of very few fitted parameters and without resorting to auxiliary sites or anisotropic atomic centers. On average, the unsigned error in the average polarizability and anisotropy compared to B3LYP are 2% and 5%, respectively. The correlation between the polarizability components from B3LYP and this approach lead to a R2 of 0.990 and a slope of 0.999. Even the F2 anisotropy, shown to be a difficult case for existing polarizability models, can be reproduced within 2% error. In addition to providing new parameters for a rapid method directly applicable to the calculation of polarizabilities, this work extends the widely used Poisson equation to areas where accurate molecular polarizabilities matter. PMID:23646034

  11. Accurate phase-shift velocimetry in rock

    NASA Astrophysics Data System (ADS)

    Shukla, Matsyendra Nath; Vallatos, Antoine; Phoenix, Vernon R.; Holmes, William M.

    2016-06-01

    Spatially resolved Pulsed Field Gradient (PFG) velocimetry techniques can provide precious information concerning flow through opaque systems, including rocks. This velocimetry data is used to enhance flow models in a wide range of systems, from oil behaviour in reservoir rocks to contaminant transport in aquifers. Phase-shift velocimetry is the fastest way to produce velocity maps but critical issues have been reported when studying flow through rocks and porous media, leading to inaccurate results. Combining PFG measurements for flow through Bentheimer sandstone with simulations, we demonstrate that asymmetries in the molecular displacement distributions within each voxel are the main source of phase-shift velocimetry errors. We show that when flow-related average molecular displacements are negligible compared to self-diffusion ones, symmetric displacement distributions can be obtained while phase measurement noise is minimised. We elaborate a complete method for the production of accurate phase-shift velocimetry maps in rocks and low porosity media and demonstrate its validity for a range of flow rates. This development of accurate phase-shift velocimetry now enables more rapid and accurate velocity analysis, potentially helping to inform both industrial applications and theoretical models.

  12. Accurate LTE abundances for some lambda Boo stars

    NASA Astrophysics Data System (ADS)

    Andrievsky, S. M.; Chernyshova, I. V.; Klochkova, V. G.; Panchuk, V. E.

    1998-04-01

    High-resolution and high S/N CCD spectra were analyzed to determine accurate LTE abundances in four lambda Boo stars: pi1 Ori, 29 Cyg, HR 8203 and 15 And. In general, 14 chemical elements were investigated. The main results are the following: all stars have a strong deficiency of the majority of investigated metals. Oxygen exhibits a moderate deficiency. The carbon abundance is close to the solar one. The results obtained support an accretion/diffusion model, which is currently adopted for the explanation of the lambda Boo phenomenon.

  13. Pink-Beam, Highly-Accurate Compact Water Cooled Slits

    SciTech Connect

    Lyndaker, Aaron; Deyhim, Alex; Jayne, Richard; Waterman, Dave; Caletka, Dave; Steadman, Paul; Dhesi, Sarnjeet

    2007-01-19

    Advanced Design Consulting, Inc. (ADC) has designed accurate compact slits for applications where high precision is required. The system consists of vertical and horizontal slit mechanisms, a vacuum vessel which houses them, water cooling lines with vacuum guards connected to the individual blades, stepper motors with linear encoders, limit (home position) switches and electrical connections including internal wiring for a drain current measurement system. The total slit size is adjustable from 0 to 15 mm both vertically and horizontally. Each of the four blades are individually controlled and motorized. In this paper, a summary of the design and Finite Element Analysis of the system are presented.

  14. Tsunami currents in ports.

    PubMed

    Borrero, Jose C; Lynett, Patrick J; Kalligeris, Nikos

    2015-10-28

    Tsunami-induced currents present an obvious hazard to maritime activities and ports in particular. The historical record is replete with accounts from ship captains and harbour masters describing their fateful encounters with currents and surges caused by these destructive waves. Despite the well-known hazard, only since the trans-oceanic tsunamis of the early twenty-first century (2004, 2010 and 2011) have coastal and port engineering practitioners begun to develop port-specific warning and response products that accurately assess the effects of tsunami-induced currents in addition to overland flooding and inundation. The hazard from strong currents induced by far-field tsunami remains an underappreciated risk in the port and maritime community. In this paper, we will discuss the history of tsunami current observations in ports, look into the current state of the art in port tsunami hazard assessment and discuss future research trends. PMID:26392622

  15. High Frequency QRS ECG Accurately Detects Cardiomyopathy

    NASA Technical Reports Server (NTRS)

    Schlegel, Todd T.; Arenare, Brian; Poulin, Gregory; Moser, Daniel R.; Delgado, Reynolds

    2005-01-01

    High frequency (HF, 150-250 Hz) analysis over the entire QRS interval of the ECG is more sensitive than conventional ECG for detecting myocardial ischemia. However, the accuracy of HF QRS ECG for detecting cardiomyopathy is unknown. We obtained simultaneous resting conventional and HF QRS 12-lead ECGs in 66 patients with cardiomyopathy (EF = 23.2 plus or minus 6.l%, mean plus or minus SD) and in 66 age- and gender-matched healthy controls using PC-based ECG software recently developed at NASA. The single most accurate ECG parameter for detecting cardiomyopathy was an HF QRS morphological score that takes into consideration the total number and severity of reduced amplitude zones (RAZs) present plus the clustering of RAZs together in contiguous leads. This RAZ score had an area under the receiver operator curve (ROC) of 0.91, and was 88% sensitive, 82% specific and 85% accurate for identifying cardiomyopathy at optimum score cut-off of 140 points. Although conventional ECG parameters such as the QRS and QTc intervals were also significantly longer in patients than controls (P less than 0.001, BBBs excluded), these conventional parameters were less accurate (area under the ROC = 0.77 and 0.77, respectively) than HF QRS morphological parameters for identifying underlying cardiomyopathy. The total amplitude of the HF QRS complexes, as measured by summed root mean square voltages (RMSVs), also differed between patients and controls (33.8 plus or minus 11.5 vs. 41.5 plus or minus 13.6 mV, respectively, P less than 0.003), but this parameter was even less accurate in distinguishing the two groups (area under ROC = 0.67) than the HF QRS morphologic and conventional ECG parameters. Diagnostic accuracy was optimal (86%) when the RAZ score from the HF QRS ECG and the QTc interval from the conventional ECG were used simultaneously with cut-offs of greater than or equal to 40 points and greater than or equal to 445 ms, respectively. In conclusion 12-lead HF QRS ECG employing

  16. Weak shock reflection

    NASA Astrophysics Data System (ADS)

    Hunter, John K.; Brio, Moysey

    2000-05-01

    We present numerical solutions of a two-dimensional inviscid Burgers equation which provides an asymptotic description of the Mach reflection of weak shocks. In our numerical solutions, the incident, reflected, and Mach shocks meet at a triple point, and there is a supersonic patch behind the triple point, as proposed by Guderley for steady weak-shock reflection. A theoretical analysis indicates that there is an expansion fan at the triple point, in addition to the three shocks. The supersonic patch is extremely small, and this work is the first time it has been resolved.

  17. GNSS Ocean Reflected Signals

    NASA Astrophysics Data System (ADS)

    Hoeg, P.

    2012-12-01

    Ocean reflected signals from the GNSS satellites (received at low-Earth orbiting satellites, airplanes and fixed mountain locations) describe the ocean surface mean height, waves, roughness, spectral reflectivity and emissivity. The estimated accuracy of the average surface height is of the order of 10 cm for smooth conditions. Thus global observations could be an important new contribution to long-term variations of the ocean mean height as well as the monitoring of ocean mesoscale eddies, which result in sea-height changes much larger than the accuracy of the GNSS technique for reflected signals. The ocean reflected signals can be divided into two set of measurements, 1) high elevation measurements (equal to low incidence angles) and 2) low elevation grazing angle measurements. For the first type the ocean reflection cross-section has a limited extent. The reflected signal is coherent with smaller errors due to ocean waves, sampling rate and the internal processing method of the receiver. For low elevations, the signal reveals the incoherent scatter process at the reflection zone. To quantify the potential of the GNSS signals for determining spectral reflectivity at low elevations, we present ocean reflection GPS measurements from the Haleakala Summit on Maui, Hawaii, revealing the spectral characteristics of both the direct satellite signal and the ocean reflected signal for low elevation angles. The characteristics of the reflected signal depend on the scattering properties of the sea surface and the footprint of the reflection zone. While the footprint size and shape in turn depends on the signal incidence angle, the ocean mean tilt, and the relative velocities of transmitter and receiver to the reflection point. Thus the scattering properties of the sea surface are related to the sea surface roughness. We present the spectral properties of the signals as received by a high precision GPS instrument, simultaneously in both phase-locked mode and open-loop raw

  18. Reflective and refractive objects for mixed reality.

    PubMed

    Knecht, Martin; Traxler, Christoph; Winklhofer, Christoph; Wimmer, Michael

    2013-04-01

    In this paper, we present a novel rendering method which integrates reflective or refractive objects into a differential instant radiosity (DIR) framework usable for mixed-reality (MR) applications. This kind of objects are very special from the light interaction point of view, as they reflect and refract incident rays. Therefore they may cause high-frequency lighting effects known as caustics. Using instant-radiosity (IR) methods to approximate these high-frequency lighting effects would require a large amount of virtual point lights (VPLs) and is therefore not desirable due to real-time constraints. Instead, our approach combines differential instant radiosity with three other methods. One method handles more accurate reflections compared to simple cubemaps by using impostors. Another method is able to calculate two refractions in real-time, and the third method uses small quads to create caustic effects. Our proposed method replaces parts in light paths that belong to reflective or refractive objects using these three methods and thus tightly integrates into DIR. In contrast to previous methods which introduce reflective or refractive objects into MR scenarios, our method produces caustics that also emit additional indirect light. The method runs at real-time frame rates, and the results show that reflective and refractive objects with caustics improve the overall impression for MR scenarios. PMID:23428441

  19. Surface reflectance degradation by microbial communities

    SciTech Connect

    Cheng, Meng -Dawn; Allman, Steve L.; Graham, David E.; Cheng, Karen R.; Pfiffner, Susan Marie; Vishnivetskaya, Tatiana A.; Desjarlais, Andre Omer

    2015-11-05

    Building envelope, such as a roof, is the interface between a building structure and the environment. Understanding of the physics of microbial interactions with the building envelope is limited. In addition to the natural weathering, microorganisms and airborne particulate matter that attach to a cool roof tend to reduce the roof reflectance over time, compromising the energy efficiency advantages of the reflective coating designs. We applied microbial ecology analysis to identify the natural communities present on the exposed coatings and investigated the reduction kinetics of the surface reflectance upon the introduction of a defined mixture of both photoautotrophic and heterotrophic microorganisms representing the natural communities. The result are (1) reflectance degradation by microbial communities follows a first-order kinetic relationship and (2) more than 50% of degradation from the initial reflectance value can be caused by microbial species alone in much less time than 3 years required by the current standard ENERGY STAR® test methods.

  20. Surface reflectance degradation by microbial communities

    DOE PAGESBeta

    Cheng, Meng -Dawn; Allman, Steve L.; Graham, David E.; Cheng, Karen R.; Pfiffner, Susan Marie; Vishnivetskaya, Tatiana A.; Desjarlais, Andre Omer

    2015-11-05

    Building envelope, such as a roof, is the interface between a building structure and the environment. Understanding of the physics of microbial interactions with the building envelope is limited. In addition to the natural weathering, microorganisms and airborne particulate matter that attach to a cool roof tend to reduce the roof reflectance over time, compromising the energy efficiency advantages of the reflective coating designs. We applied microbial ecology analysis to identify the natural communities present on the exposed coatings and investigated the reduction kinetics of the surface reflectance upon the introduction of a defined mixture of both photoautotrophic and heterotrophicmore » microorganisms representing the natural communities. The result are (1) reflectance degradation by microbial communities follows a first-order kinetic relationship and (2) more than 50% of degradation from the initial reflectance value can be caused by microbial species alone in much less time than 3 years required by the current standard ENERGY STAR® test methods.« less

  1. Current sensor

    DOEpatents

    Yakymyshyn, Christopher Paul; Brubaker, Michael Allen; Yakymyshyn, Pamela Jane

    2007-01-16

    A current sensor is described that uses a plurality of magnetic field sensors positioned around a current carrying conductor. The sensor can be hinged to allow clamping to a conductor. The current sensor provides high measurement accuracy for both DC and AC currents, and is substantially immune to the effects of temperature, conductor position, nearby current carrying conductors and aging.

  2. Absolute reflectivity measurements at 44.79 A of sputter deposited multilayer x-ray mirrors.

    PubMed

    Arbaoui, M; Barchewitz, R; Sella, C; Youn, K B

    1990-02-01

    Multilayer x-ray mirrors have been deposited using a dc triode sputtering system, which incorporates an accurate method of thickness monitoring based on the dependence of the deposition rate on the target current. Thickness can be controlled with an accuracy of better than 0.1 A. High efficiency W-C and Ni-C multilayer mirrors have been synthesized and tested at 1.54-A (CuKoalpha) and 44.79-A (CKalpha). Absolute reflectivity measurements at lambda = 44.79-A (CKalpha) have been carried out. In this case the incident beam is previously polarized by a premonochromator equipped with a pair of parallel-plane multilayer mirrors fixed at an angle close to the Brewster (theta ? 45 degrees ). Thus the measured reflectivities are not affected by a progressive variation of the P-component. PMID:20556133

  3. More accurate phylogenies inferred from low-recombination regions in the presence of incomplete lineage sorting.

    PubMed

    Pease, James B; Hahn, Matthew W

    2013-08-01

    When speciation events occur in rapid succession, incomplete lineage sorting (ILS) can cause disagreement among individual gene trees. The probability that ILS affects a given locus is directly related to its effective population size (Ne ), which in turn is proportional to the recombination rate if there is strong selection across the genome. Based on these expectations, we hypothesized that low-recombination regions of the genome, as well as sex chromosomes and nonrecombining chromosomes, should exhibit lower levels of ILS. We tested this hypothesis in phylogenomic datasets from primates, the Drosophila melanogaster clade, and the Drosophila simulans clade. In all three cases, regions of the genome with low or no recombination showed significantly stronger support for the putative species tree, although results from the X chromosome differed among clades. Our results suggest that recurrent selection is acting in these low-recombination regions, such that current levels of diversity also reflect past decreases in the effective population size at these same loci. The results also demonstrate how considering the genomic context of a gene tree can assist in more accurate determination of the true species phylogeny, especially in cases where a whole-genome phylogeny appears to be an unresolvable polytomy. PMID:23888858

  4. Accurate moving cast shadow suppression based on local color constancy detection.

    PubMed

    Amato, Ariel; Mozerov, Mikhail G; Bagdanov, Andrew D; Gonzàlez, Jordi

    2011-10-01

    This paper describes a novel framework for detection and suppression of properly shadowed regions for most possible scenarios occurring in real video sequences. Our approach requires no prior knowledge about the scene, nor is it restricted to specific scene structures. Furthermore, the technique can detect both achromatic and chromatic shadows even in the presence of camouflage that occurs when foreground regions are very similar in color to shadowed regions. The method exploits local color constancy properties due to reflectance suppression over shadowed regions. To detect shadowed regions in a scene, the values of the background image are divided by values of the current frame in the RGB color space. We show how this luminance ratio can be used to identify segments with low gradient constancy, which in turn distinguish shadows from foreground. Experimental results on a collection of publicly available datasets illustrate the superior performance of our method compared with the most sophisticated, state-of-the-art shadow detection algorithms. These results show that our approach is robust and accurate over a broad range of shadow types and challenging video conditions. PMID:21435975

  5. Reflections on Miniature Golf.

    ERIC Educational Resources Information Center

    Powell, Nancy Norem; And Others

    1994-01-01

    Describes a transformational geometry project in which groups of students explore symmetry, reflections, translations, rotations, and dilations to design and create one hole of miniature golf large enough to play on. Includes unit plan for transformational geometry. (MKR)

  6. Seasonal soybean crop reflectance

    NASA Technical Reports Server (NTRS)

    Lemaster, E. W. (Principal Investigator); Chance, J. E.

    1983-01-01

    Data are presented from field measurements of 1980 including 5 acquisitions of handheld radiometer reflectance measurements, 7 complete sets of parameters for implementing the Suits mode, and other biophysical parameters to characterize the soybean canopy. LANDSAT calculations on the simulated Brazilian soybean reflectance are included along with data collected during the summer and fall on 1981 on soybean single leaf optical parameters for three irrigation treatments. Tests of the Suits vegetative canopy reflectance model for the full hemisphere of observer directions as well as the nadir direction show moderate agreement for the visible channels of the MSS and poor agreement in the near infrared channel. Temporal changes in the spectral characteristics of the single leaves were seen to occur as a function of maturity which demonstrates that the absorptance of a soybean single leaf is more a function of thetransmittancee characteristics than the seasonally consistent single leaf reflectance.

  7. Andreev reflection in graphene

    NASA Astrophysics Data System (ADS)

    Beenakker, Carlo

    2007-03-01

    Relativity and superconductivity have no common ground in ordinary matter, because the velocity of electrons is only a small fraction of the velocity of light. The unusual band structure of a single layer of carbon atoms (graphene) contains negatively and positively charged particles that move as relativistic electrons and positrons. The electron-like particles in the conduction band can be converted into positron-like particles in the valence band when they are reflected by a superconductor. (The missing charge of 2e enters the superconductor as a Cooper pair.) This interband reflection process can be distinguished from the usual intraband Andreev reflection, because the reflection angle has the opposite sign. A new phenomenology of graphene--superconductor junctions is predicted, including an anomalous scaling of the supercurrent with the length of the junction and the existence of charge-neutral modes propagating along the interface.

  8. Approximating Reflectance and Transmittance of Vegetation Using Multiple Spectral Invariants

    NASA Astrophysics Data System (ADS)

    Mottus, M.

    2011-12-01

    Canopy spectral invariants, eigenvalues of the radiative transfer equation and photon recollision probability are some of the new theoretical tools that have been applied in remote sensing of vegetation and atmosphere. The theoretical approach based on spectral invariants, informally also referred to as the p-theory, owns its attractivity to several factors. Firstly, it provides a rapid and physically-based way of describing canopy scattering. Secondly, the p-theory aims at parameterizing canopy structure in reflectance models using a simple and intuitive concept which can be applied at various structural levels, from shoot to tree crown. The theory has already been applied at scales from the molecular level to forest stands. The most important shortcoming of the p-theory lies in its inability to predict the directionality of scattering. The theory is currently based on only one physical parameter, the photon recollision probability p. It is evident that one parameter cannot contain enough information to reasonably predict the observed complex reflectance patterns produced by natural vegetation canopies. Without estimating scattering directionality, however, the theory cannot be compared with even the most simple (and well-tested) two-stream vegetation reflectance models. In this study, we evaluate the possibility to use additional parameters to fit the measured reflectance and transmittance of a vegetation stand. As a first step, the parameters are applied to separate canopy scattering into reflectance and transmittance. New parameters are introduced following the general approach of eigenvector expansion. Thus, the new parameters are coined higher-order spectral invariants. Calculation of higher-order invariants is based on separating first-order scattering from total scattering. Thus, the method explicitly accounts for different view geometries with different fractions of visible sunlit canopy (e.g., hot-spot). It additionally allows to produce different

  9. Accurately Mapping M31's Microlensing Population

    NASA Astrophysics Data System (ADS)

    Crotts, Arlin

    2004-07-01

    We propose to augment an existing microlensing survey of M31 with source identifications provided by a modest amount of ACS {and WFPC2 parallel} observations to yield an accurate measurement of the masses responsible for microlensing in M31, and presumably much of its dark matter. The main benefit of these data is the determination of the physical {or "einstein"} timescale of each microlensing event, rather than an effective {"FWHM"} timescale, allowing masses to be determined more than twice as accurately as without HST data. The einstein timescale is the ratio of the lensing cross-sectional radius and relative velocities. Velocities are known from kinematics, and the cross-section is directly proportional to the {unknown} lensing mass. We cannot easily measure these quantities without knowing the amplification, hence the baseline magnitude, which requires the resolution of HST to find the source star. This makes a crucial difference because M31 lens m ass determinations can be more accurate than those towards the Magellanic Clouds through our Galaxy's halo {for the same number of microlensing events} due to the better constrained geometry in the M31 microlensing situation. Furthermore, our larger survey, just completed, should yield at least 100 M31 microlensing events, more than any Magellanic survey. A small amount of ACS+WFPC2 imaging will deliver the potential of this large database {about 350 nights}. For the whole survey {and a delta-function mass distribution} the mass error should approach only about 15%, or about 6% error in slope for a power-law distribution. These results will better allow us to pinpoint the lens halo fraction, and the shape of the halo lens spatial distribution, and allow generalization/comparison of the nature of halo dark matter in spiral galaxies. In addition, we will be able to establish the baseline magnitude for about 50, 000 variable stars, as well as measure an unprecedentedly deta iled color-magnitude diagram and luminosity

  10. Accurate measurement of unsteady state fluid temperature

    NASA Astrophysics Data System (ADS)

    Jaremkiewicz, Magdalena

    2016-07-01

    In this paper, two accurate methods for determining the transient fluid temperature were presented. Measurements were conducted for boiling water since its temperature is known. At the beginning the thermometers are at the ambient temperature and next they are immediately immersed into saturated water. The measurements were carried out with two thermometers of different construction but with the same housing outer diameter equal to 15 mm. One of them is a K-type industrial thermometer widely available commercially. The temperature indicated by the thermometer was corrected considering the thermometers as the first or second order inertia devices. The new design of a thermometer was proposed and also used to measure the temperature of boiling water. Its characteristic feature is a cylinder-shaped housing with the sheath thermocouple located in its center. The temperature of the fluid was determined based on measurements taken in the axis of the solid cylindrical element (housing) using the inverse space marching method. Measurements of the transient temperature of the air flowing through the wind tunnel using the same thermometers were also carried out. The proposed measurement technique provides more accurate results compared with measurements using industrial thermometers in conjunction with simple temperature correction using the inertial thermometer model of the first or second order. By comparing the results, it was demonstrated that the new thermometer allows obtaining the fluid temperature much faster and with higher accuracy in comparison to the industrial thermometer. Accurate measurements of the fast changing fluid temperature are possible due to the low inertia thermometer and fast space marching method applied for solving the inverse heat conduction problem.

  11. The first accurate description of an aurora

    NASA Astrophysics Data System (ADS)

    Schröder, Wilfried

    2006-12-01

    As technology has advanced, the scientific study of auroral phenomena has increased by leaps and bounds. A look back at the earliest descriptions of aurorae offers an interesting look into how medieval scholars viewed the subjects that we study.Although there are earlier fragmentary references in the literature, the first accurate description of the aurora borealis appears to be that published by the German Catholic scholar Konrad von Megenberg (1309-1374) in his book Das Buch der Natur (The Book of Nature). The book was written between 1349 and 1350.

  12. Are Kohn-Sham conductances accurate?

    PubMed

    Mera, H; Niquet, Y M

    2010-11-19

    We use Fermi-liquid relations to address the accuracy of conductances calculated from the single-particle states of exact Kohn-Sham (KS) density functional theory. We demonstrate a systematic failure of this procedure for the calculation of the conductance, and show how it originates from the lack of renormalization in the KS spectral function. In certain limits this failure can lead to a large overestimation of the true conductance. We also show, however, that the KS conductances can be accurate for single-channel molecular junctions and systems where direct Coulomb interactions are strongly dominant. PMID:21231333

  13. Accurate density functional thermochemistry for larger molecules.

    SciTech Connect

    Raghavachari, K.; Stefanov, B. B.; Curtiss, L. A.; Lucent Tech.

    1997-06-20

    Density functional methods are combined with isodesmic bond separation reaction energies to yield accurate thermochemistry for larger molecules. Seven different density functionals are assessed for the evaluation of heats of formation, Delta H 0 (298 K), for a test set of 40 molecules composed of H, C, O and N. The use of bond separation energies results in a dramatic improvement in the accuracy of all the density functionals. The B3-LYP functional has the smallest mean absolute deviation from experiment (1.5 kcal mol/f).

  14. Spatial averaging errors in creating hemispherical reflectance (albedo) maps from directional reflectance data

    SciTech Connect

    Kimes, D.S.; Kerber, A.G.; Sellers, P.J. )

    1993-06-01

    The problems in moving from a radiance measurement made for a particular sun-target-sensor geometry to an accurate estimate of the hemispherical reflectance are considerable. A knowledge-based system called VEG was used in this study to infer hemispherical reflectance. Given directional reflectance(s) and the sun angle, VEG selects the most suitable inference technique(s) and estimates the surface hemispherical reflectance with an estimate of the error. Ideally, VEG is applied to homogeneous vegetation. However, what is typically done in GCM (global circulation model) models and related studies is to obtain an average hemispherical reflectance on a square grid cell on the order of 200 km x 200 km. All available directional data for a given cell are averaged (for each view direction), and then a particular technique for inferring hemispherical reflectance is applied to this averaged data. Any given grid cell can contain several surface types that directionally scatter radiation very differently. When averaging over a set of view angles, the resulting mean values may be atypical of the actual surface types that occur on the ground, and the resulting inferred hemispherical reflectance can be in error. These errors were explored by creating a simulated scene and applying VEG to estimate the area-averaged hemispherical reflectance using various sampling procedures. The reduction in the hemispherical reflectance errors provided by using VEG ranged from a factor of 2-4, depending on conditions. This improvement represents a shift from the calculation of a hemispherical reflectance product of relative value (errors of 20% or more), to a product that could be used quantitatively in global modeling applications, where the requirement is for errors to be limited to around 5-10 %.

  15. Defining Reflection: Another Look at John Dewey and Reflective Thinking.

    ERIC Educational Resources Information Center

    Rodgers, Carol

    2002-01-01

    Examines four criteria that characterize John Dewey's view of reflective thought: reflection as a meaning-making process; reflection as a systematic, rigorous, disciplined way of thinking with its roots in scientific inquiry; reflection needs to happen in community, in interaction with others; and reflection requires attitudes that value the…

  16. Analytical elimination of substrate backside reflections from reflectance measurements.

    PubMed

    Wilbrandt, Steffen; Stenzel, Olaf

    2016-09-01

    An analytical approach to eliminate substrate backside reflections from measured reflectance of an unknown optical coating has been deducted. Thereby, measured transmittance, reflectance, and backside reflectance of the coating and transmittance and reflectance of the uncoated substrate at the desired angle of incidence and polarization state are required as input data. In the underlying theory, layer and substrate materials may be absorbing. PMID:27607274

  17. Accurate basis set truncation for wavefunction embedding

    NASA Astrophysics Data System (ADS)

    Barnes, Taylor A.; Goodpaster, Jason D.; Manby, Frederick R.; Miller, Thomas F.

    2013-07-01

    Density functional theory (DFT) provides a formally exact framework for performing embedded subsystem electronic structure calculations, including DFT-in-DFT and wavefunction theory-in-DFT descriptions. In the interest of efficiency, it is desirable to truncate the atomic orbital basis set in which the subsystem calculation is performed, thus avoiding high-order scaling with respect to the size of the MO virtual space. In this study, we extend a recently introduced projection-based embedding method [F. R. Manby, M. Stella, J. D. Goodpaster, and T. F. Miller III, J. Chem. Theory Comput. 8, 2564 (2012)], 10.1021/ct300544e to allow for the systematic and accurate truncation of the embedded subsystem basis set. The approach is applied to both covalently and non-covalently bound test cases, including water clusters and polypeptide chains, and it is demonstrated that errors associated with basis set truncation are controllable to well within chemical accuracy. Furthermore, we show that this approach allows for switching between accurate projection-based embedding and DFT embedding with approximate kinetic energy (KE) functionals; in this sense, the approach provides a means of systematically improving upon the use of approximate KE functionals in DFT embedding.

  18. How Accurately can we Calculate Thermal Systems?

    SciTech Connect

    Cullen, D; Blomquist, R N; Dean, C; Heinrichs, D; Kalugin, M A; Lee, M; Lee, Y; MacFarlan, R; Nagaya, Y; Trkov, A

    2004-04-20

    I would like to determine how accurately a variety of neutron transport code packages (code and cross section libraries) can calculate simple integral parameters, such as K{sub eff}, for systems that are sensitive to thermal neutron scattering. Since we will only consider theoretical systems, we cannot really determine absolute accuracy compared to any real system. Therefore rather than accuracy, it would be more precise to say that I would like to determine the spread in answers that we obtain from a variety of code packages. This spread should serve as an excellent indicator of how accurately we can really model and calculate such systems today. Hopefully, eventually this will lead to improvements in both our codes and the thermal scattering models that they use in the future. In order to accomplish this I propose a number of extremely simple systems that involve thermal neutron scattering that can be easily modeled and calculated by a variety of neutron transport codes. These are theoretical systems designed to emphasize the effects of thermal scattering, since that is what we are interested in studying. I have attempted to keep these systems very simple, and yet at the same time they include most, if not all, of the important thermal scattering effects encountered in a large, water-moderated, uranium fueled thermal system, i.e., our typical thermal reactors.

  19. Accurate shear measurement with faint sources

    SciTech Connect

    Zhang, Jun; Foucaud, Sebastien; Luo, Wentao E-mail: walt@shao.ac.cn

    2015-01-01

    For cosmic shear to become an accurate cosmological probe, systematic errors in the shear measurement method must be unambiguously identified and corrected for. Previous work of this series has demonstrated that cosmic shears can be measured accurately in Fourier space in the presence of background noise and finite pixel size, without assumptions on the morphologies of galaxy and PSF. The remaining major source of error is source Poisson noise, due to the finiteness of source photon number. This problem is particularly important for faint galaxies in space-based weak lensing measurements, and for ground-based images of short exposure times. In this work, we propose a simple and rigorous way of removing the shear bias from the source Poisson noise. Our noise treatment can be generalized for images made of multiple exposures through MultiDrizzle. This is demonstrated with the SDSS and COSMOS/ACS data. With a large ensemble of mock galaxy images of unrestricted morphologies, we show that our shear measurement method can achieve sub-percent level accuracy even for images of signal-to-noise ratio less than 5 in general, making it the most promising technique for cosmic shear measurement in the ongoing and upcoming large scale galaxy surveys.

  20. Accurate pose estimation for forensic identification

    NASA Astrophysics Data System (ADS)

    Merckx, Gert; Hermans, Jeroen; Vandermeulen, Dirk

    2010-04-01

    In forensic authentication, one aims to identify the perpetrator among a series of suspects or distractors. A fundamental problem in any recognition system that aims for identification of subjects in a natural scene is the lack of constrains on viewing and imaging conditions. In forensic applications, identification proves even more challenging, since most surveillance footage is of abysmal quality. In this context, robust methods for pose estimation are paramount. In this paper we will therefore present a new pose estimation strategy for very low quality footage. Our approach uses 3D-2D registration of a textured 3D face model with the surveillance image to obtain accurate far field pose alignment. Starting from an inaccurate initial estimate, the technique uses novel similarity measures based on the monogenic signal to guide a pose optimization process. We will illustrate the descriptive strength of the introduced similarity measures by using them directly as a recognition metric. Through validation, using both real and synthetic surveillance footage, our pose estimation method is shown to be accurate, and robust to lighting changes and image degradation.

  1. Accurate determination of characteristic relative permeability curves

    NASA Astrophysics Data System (ADS)

    Krause, Michael H.; Benson, Sally M.

    2015-09-01

    A recently developed technique to accurately characterize sub-core scale heterogeneity is applied to investigate the factors responsible for flowrate-dependent effective relative permeability curves measured on core samples in the laboratory. The dependency of laboratory measured relative permeability on flowrate has long been both supported and challenged by a number of investigators. Studies have shown that this apparent flowrate dependency is a result of both sub-core scale heterogeneity and outlet boundary effects. However this has only been demonstrated numerically for highly simplified models of porous media. In this paper, flowrate dependency of effective relative permeability is demonstrated using two rock cores, a Berea Sandstone and a heterogeneous sandstone from the Otway Basin Pilot Project in Australia. Numerical simulations of steady-state coreflooding experiments are conducted at a number of injection rates using a single set of input characteristic relative permeability curves. Effective relative permeability is then calculated from the simulation data using standard interpretation methods for calculating relative permeability from steady-state tests. Results show that simplified approaches may be used to determine flowrate-independent characteristic relative permeability provided flow rate is sufficiently high, and the core heterogeneity is relatively low. It is also shown that characteristic relative permeability can be determined at any typical flowrate, and even for geologically complex models, when using accurate three-dimensional models.

  2. Improved Algorithms for Accurate Retrieval of UV - Visible Diffuse Attenuation Coefficients in Optically Complex, Inshore Waters

    NASA Technical Reports Server (NTRS)

    Cao, Fang; Fichot, Cedric G.; Hooker, Stanford B.; Miller, William L.

    2014-01-01

    Photochemical processes driven by high-energy ultraviolet radiation (UVR) in inshore, estuarine, and coastal waters play an important role in global bio geochemical cycles and biological systems. A key to modeling photochemical processes in these optically complex waters is an accurate description of the vertical distribution of UVR in the water column which can be obtained using the diffuse attenuation coefficients of down welling irradiance (Kd()). The Sea UV Sea UVc algorithms (Fichot et al., 2008) can accurately retrieve Kd ( 320, 340, 380,412, 443 and 490 nm) in oceanic and coastal waters using multispectral remote sensing reflectances (Rrs(), Sea WiFS bands). However, SeaUVSeaUVc algorithms are currently not optimized for use in optically complex, inshore waters, where they tend to severely underestimate Kd(). Here, a new training data set of optical properties collected in optically complex, inshore waters was used to re-parameterize the published SeaUVSeaUVc algorithms, resulting in improved Kd() retrievals for turbid, estuarine waters. Although the updated SeaUVSeaUVc algorithms perform best in optically complex waters, the published SeaUVSeaUVc models still perform well in most coastal and oceanic waters. Therefore, we propose a composite set of SeaUVSeaUVc algorithms, optimized for Kd() retrieval in almost all marine systems, ranging from oceanic to inshore waters. The composite algorithm set can retrieve Kd from ocean color with good accuracy across this wide range of water types (e.g., within 13 mean relative error for Kd(340)). A validation step using three independent, in situ data sets indicates that the composite SeaUVSeaUVc can generate accurate Kd values from 320 490 nm using satellite imagery on a global scale. Taking advantage of the inherent benefits of our statistical methods, we pooled the validation data with the training set, obtaining an optimized composite model for estimating Kd() in UV wavelengths for almost all marine waters. This

  3. Comparison of diffuse sky irradiance calculation methods and effect on surface reflectance retrieval from an automated radiometric calibration test site

    NASA Astrophysics Data System (ADS)

    Leisso, Nathan; Czapla-Myers, Jeffrey

    2011-10-01

    The Remote Sensing Group (RSG) at the University of Arizona is currently refining an automated system for the absolute radiometric calibration of earth-observing sensors. The Radiometric Calibration Test Site (RadCaTS) relies on semi-permanent instrumentation at the Railroad Valley (RRV) test site to collect data from which surface reflectance and an atmospheric characterization is determined. Multispectral surface reflectance is determined from calibrated ground viewing radiometers and assimilated to determine the hyperspectral reflectance used in radiative transfer calculations. The reflectance retrieval algorithm relies on an accurate determination of the diffuse sky irradiance for the time of interest. Currently, diffuse sky irradiance is modeled using the atmospheric characterization as input into MODTRAN5. This work investigates the accuracy of the diffuse sky modeling by comparing modeled results to measurements made at the test site. Diffuse sky irradiance from several alternative methods are also presented. Surface reflectance is computed and compared to in-situ measurements taken with a portable spectoradiometer.

  4. Foundations of Refugee Rights: How Legal Language Reflects Current Trends.

    ERIC Educational Resources Information Center

    Goldsmith, Andrew

    1996-01-01

    Addresses the recent anti-immigrant sentiment in the United States and examines the forces causing it. The article examines legal language and opinion in court cases showing shifting anti-immigrant sentiment, including the language used in California's Proposition 187, and argues that this legal language in which court decisions and legislation…

  5. Reflections on Contemporary Currents in Writing Center Work

    ERIC Educational Resources Information Center

    Lunsford, Andrea A.; Ede, Lisa

    2011-01-01

    This article presents the text of a speech presented at The International Writing Centers Association and the National Conference on Peer Tutoring (IWCA-NCPTW) joint conference in Baltimore, Maryland, in November 2010. It stemmed from a larger project--a collection of previously published and new essays titled "Writing Together: Collaboration in…

  6. Multilingualism in Australia: Reflections on Current and Future Research Trends

    ERIC Educational Resources Information Center

    Rubino, Antonia

    2010-01-01

    This paper gives a critical overview of Australian research in the area of immigrant languages, arguing that this field of study is a significant component of the wider applied linguistics scene in Australia and has also contributed to enhancing the broad appreciation of the cultural and linguistic diversity of the country. It shows that research…

  7. A Framework for Teacher Reflectivity.

    ERIC Educational Resources Information Center

    Stanley, Claire

    1998-01-01

    Proposes a framework for teacher reflection based on a longitudinal study of the development of six experienced second-language teachers who attempted to implement reflection and reflective action into their teaching practice. The resulting framework included several phases in the development of reflective teaching: engaging with reflection,…

  8. Knowledge translation: the role and place of practice reflection.

    PubMed

    Lockyer, Jocelyn; Gondocz, S Tunde; Thivierge, Robert L

    2004-01-01

    Reflection is the mechanism by which we contemplate and try to understand relatively complex and sometimes troubling ideas for which there is no obvious solution. Reflection allows us to transform current ideas and experiences into new knowledge and action. Personal experiences and organizational feedback can trigger reflection, whereas a lack of time, available colleagues, and social networks detract from the ability professionals have to reflect. Educational programs can encourage reflection through the judicious use of case-based discussion, formal and informal needs assessments, and commitment to change exercises. Learning journals and personal learning projects are self-directed methods that facilitate reflection. In the workplace, critical incident techniques and debriefing of cases provide opportunities for thoughtful inquiry. Additional study is needed to understand how and why reflection works to transform surface learning into deep learning and change in practice; how reflection enhances the integration of reading, collegial interchange, and classroom discussion into practice; and how technology can enhance reflection. PMID:15069912

  9. A Reflection on Belief

    ERIC Educational Resources Information Center

    Cuevas, Joshua A.

    2013-01-01

    This paper explores the phenomenon in which, for many people, subjective personal belief is viewed as a more accurate representation of reality than objective scientific knowledge developed over the course of human history and transmitted through secular education. The first half of the article is based on personal observations of the author…

  10. Accurate Thermal Stresses for Beams: Normal Stress

    NASA Technical Reports Server (NTRS)

    Johnson, Theodore F.; Pilkey, Walter D.

    2003-01-01

    Formulations for a general theory of thermoelasticity to generate accurate thermal stresses for structural members of aeronautical vehicles were developed in 1954 by Boley. The formulation also provides three normal stresses and a shear stress along the entire length of the beam. The Poisson effect of the lateral and transverse normal stresses on a thermally loaded beam is taken into account in this theory by employing an Airy stress function. The Airy stress function enables the reduction of the three-dimensional thermal stress problem to a two-dimensional one. Numerical results from the general theory of thermoelasticity are compared to those obtained from strength of materials. It is concluded that the theory of thermoelasticity for prismatic beams proposed in this paper can be used instead of strength of materials when precise stress results are desired.

  11. Accurate Thermal Stresses for Beams: Normal Stress

    NASA Technical Reports Server (NTRS)

    Johnson, Theodore F.; Pilkey, Walter D.

    2002-01-01

    Formulations for a general theory of thermoelasticity to generate accurate thermal stresses for structural members of aeronautical vehicles were developed in 1954 by Boley. The formulation also provides three normal stresses and a shear stress along the entire length of the beam. The Poisson effect of the lateral and transverse normal stresses on a thermally loaded beam is taken into account in this theory by employing an Airy stress function. The Airy stress function enables the reduction of the three-dimensional thermal stress problem to a two-dimensional one. Numerical results from the general theory of thermoelasticity are compared to those obtained from strength of materials. It is concluded that the theory of thermoelasticity for prismatic beams proposed in this paper can be used instead of strength of materials when precise stress results are desired.

  12. Highly accurate articulated coordinate measuring machine

    DOEpatents

    Bieg, Lothar F.; Jokiel, Jr., Bernhard; Ensz, Mark T.; Watson, Robert D.

    2003-12-30

    Disclosed is a highly accurate articulated coordinate measuring machine, comprising a revolute joint, comprising a circular encoder wheel, having an axis of rotation; a plurality of marks disposed around at least a portion of the circumference of the encoder wheel; bearing means for supporting the encoder wheel, while permitting free rotation of the encoder wheel about the wheel's axis of rotation; and a sensor, rigidly attached to the bearing means, for detecting the motion of at least some of the marks as the encoder wheel rotates; a probe arm, having a proximal end rigidly attached to the encoder wheel, and having a distal end with a probe tip attached thereto; and coordinate processing means, operatively connected to the sensor, for converting the output of the sensor into a set of cylindrical coordinates representing the position of the probe tip relative to a reference cylindrical coordinate system.

  13. The thermodynamic cost of accurate sensory adaptation

    NASA Astrophysics Data System (ADS)

    Tu, Yuhai

    2015-03-01

    Living organisms need to obtain and process environment information accurately in order to make decisions critical for their survival. Much progress have been made in identifying key components responsible for various biological functions, however, major challenges remain to understand system-level behaviors from the molecular-level knowledge of biology and to unravel possible physical principles for the underlying biochemical circuits. In this talk, we will present some recent works in understanding the chemical sensory system of E. coli by combining theoretical approaches with quantitative experiments. We focus on addressing the questions on how cells process chemical information and adapt to varying environment, and what are the thermodynamic limits of key regulatory functions, such as adaptation.

  14. Accurate numerical solutions of conservative nonlinear oscillators

    NASA Astrophysics Data System (ADS)

    Khan, Najeeb Alam; Nasir Uddin, Khan; Nadeem Alam, Khan

    2014-12-01

    The objective of this paper is to present an investigation to analyze the vibration of a conservative nonlinear oscillator in the form u" + lambda u + u^(2n-1) + (1 + epsilon^2 u^(4m))^(1/2) = 0 for any arbitrary power of n and m. This method converts the differential equation to sets of algebraic equations and solve numerically. We have presented for three different cases: a higher order Duffing equation, an equation with irrational restoring force and a plasma physics equation. It is also found that the method is valid for any arbitrary order of n and m. Comparisons have been made with the results found in the literature the method gives accurate results.

  15. Accurate Telescope Mount Positioning with MEMS Accelerometers

    NASA Astrophysics Data System (ADS)

    Mészáros, L.; Jaskó, A.; Pál, A.; Csépány, G.

    2014-08-01

    This paper describes the advantages and challenges of applying microelectromechanical accelerometer systems (MEMS accelerometers) in order to attain precise, accurate, and stateless positioning of telescope mounts. This provides a completely independent method from other forms of electronic, optical, mechanical or magnetic feedback or real-time astrometry. Our goal is to reach the subarcminute range which is considerably smaller than the field-of-view of conventional imaging telescope systems. Here we present how this subarcminute accuracy can be achieved with very cheap MEMS sensors and we also detail how our procedures can be extended in order to attain even finer measurements. In addition, our paper discusses how can a complete system design be implemented in order to be a part of a telescope control system.

  16. Apparatus for accurately measuring high temperatures

    DOEpatents

    Smith, Douglas D.

    1985-01-01

    The present invention is a thermometer used for measuring furnace temperaes in the range of about 1800.degree. to 2700.degree. C. The thermometer comprises a broadband multicolor thermal radiation sensor positioned to be in optical alignment with the end of a blackbody sight tube extending into the furnace. A valve-shutter arrangement is positioned between the radiation sensor and the sight tube and a chamber for containing a charge of high pressure gas is positioned between the valve-shutter arrangement and the radiation sensor. A momentary opening of the valve shutter arrangement allows a pulse of the high gas to purge the sight tube of air-borne thermal radiation contaminants which permits the radiation sensor to accurately measure the thermal radiation emanating from the end of the sight tube.

  17. Apparatus for accurately measuring high temperatures

    DOEpatents

    Smith, D.D.

    The present invention is a thermometer used for measuring furnace temperatures in the range of about 1800/sup 0/ to 2700/sup 0/C. The thermometer comprises a broadband multicolor thermal radiation sensor positioned to be in optical alignment with the end of a blackbody sight tube extending into the furnace. A valve-shutter arrangement is positioned between the radiation sensor and the sight tube and a chamber for containing a charge of high pressure gas is positioned between the valve-shutter arrangement and the radiation sensor. A momentary opening of the valve shutter arrangement allows a pulse of the high gas to purge the sight tube of air-borne thermal radiation contaminants which permits the radiation sensor to accurately measure the thermal radiation emanating from the end of the sight tube.

  18. The high cost of accurate knowledge.

    PubMed

    Sutcliffe, Kathleen M; Weber, Klaus

    2003-05-01

    Many business thinkers believe it's the role of senior managers to scan the external environment to monitor contingencies and constraints, and to use that precise knowledge to modify the company's strategy and design. As these thinkers see it, managers need accurate and abundant information to carry out that role. According to that logic, it makes sense to invest heavily in systems for collecting and organizing competitive information. Another school of pundits contends that, since today's complex information often isn't precise anyway, it's not worth going overboard with such investments. In other words, it's not the accuracy and abundance of information that should matter most to top executives--rather, it's how that information is interpreted. After all, the role of senior managers isn't just to make decisions; it's to set direction and motivate others in the face of ambiguities and conflicting demands. Top executives must interpret information and communicate those interpretations--they must manage meaning more than they must manage information. So which of these competing views is the right one? Research conducted by academics Sutcliffe and Weber found that how accurate senior executives are about their competitive environments is indeed less important for strategy and corresponding organizational changes than the way in which they interpret information about their environments. Investments in shaping those interpretations, therefore, may create a more durable competitive advantage than investments in obtaining and organizing more information. And what kinds of interpretations are most closely linked with high performance? Their research suggests that high performers respond positively to opportunities, yet they aren't overconfident in their abilities to take advantage of those opportunities. PMID:12747164

  19. Accurate Weather Forecasting for Radio Astronomy

    NASA Astrophysics Data System (ADS)

    Maddalena, Ronald J.

    2010-01-01

    The NRAO Green Bank Telescope routinely observes at wavelengths from 3 mm to 1 m. As with all mm-wave telescopes, observing conditions depend upon the variable atmospheric water content. The site provides over 100 days/yr when opacities are low enough for good observing at 3 mm, but winds on the open-air structure reduce the time suitable for 3-mm observing where pointing is critical. Thus, to maximum productivity the observing wavelength needs to match weather conditions. For 6 years the telescope has used a dynamic scheduling system (recently upgraded; www.gb.nrao.edu/DSS) that requires accurate multi-day forecasts for winds and opacities. Since opacity forecasts are not provided by the National Weather Services (NWS), I have developed an automated system that takes available forecasts, derives forecasted opacities, and deploys the results on the web in user-friendly graphical overviews (www.gb.nrao.edu/ rmaddale/Weather). The system relies on the "North American Mesoscale" models, which are updated by the NWS every 6 hrs, have a 12 km horizontal resolution, 1 hr temporal resolution, run to 84 hrs, and have 60 vertical layers that extend to 20 km. Each forecast consists of a time series of ground conditions, cloud coverage, etc, and, most importantly, temperature, pressure, humidity as a function of height. I use the Liebe's MWP model (Radio Science, 20, 1069, 1985) to determine the absorption in each layer for each hour for 30 observing wavelengths. Radiative transfer provides, for each hour and wavelength, the total opacity and the radio brightness of the atmosphere, which contributes substantially at some wavelengths to Tsys and the observational noise. Comparisons of measured and forecasted Tsys at 22.2 and 44 GHz imply that the forecasted opacities are good to about 0.01 Nepers, which is sufficient for forecasting and accurate calibration. Reliability is high out to 2 days and degrades slowly for longer-range forecasts.

  20. Design for reflection.

    PubMed

    Bagnara, Sebastiano; Pozzi, Simone

    2012-01-01

    Since a few years, a number of academic papers have been proposing to shift from user-centered design to human-centered (or person) design. In this contribution, we discuss as the common tread underlying these works the idea that design should also address the reflective part of our human experience, and not only aim to maximize the experiential aspects. Our review is complemented with examples derived from the internet world and from ICT consumer products. The main research areas we see as promising for the approach of "design for reflection" are: design for pauses, design for detachment, design for serendipity. PMID:22316867

  1. Mystic Reflection Groups

    NASA Astrophysics Data System (ADS)

    Bazlov, Yuri; Berenstein, Arkady

    2014-04-01

    This paper aims to systematically study mystic reflection groups that emerged independently in the paper [Selecta Math. (N.S.) 14 (2009), 325-372] by the authors and in the paper [Algebr. Represent. Theory 13 (2010), 127-158] by Kirkman, Kuzmanovich and Zhang. A detailed analysis of this class of groups reveals that they are in a nontrivial correspondence with the complex reflection groups G(m,p,n). We also prove that the group algebras of corresponding groups are isomorphic and classify all such groups up to isomorphism.

  2. Method for accurate growth of vertical-cavity surface-emitting lasers

    DOEpatents

    Chalmers, S.A.; Killeen, K.P.; Lear, K.L.

    1995-03-14

    The authors report a method for accurate growth of vertical-cavity surface-emitting lasers (VCSELs). The method uses a single reflectivity spectrum measurement to determine the structure of the partially completed VCSEL at a critical point of growth. This information, along with the extracted growth rates, allows imprecisions in growth parameters to be compensated for during growth of the remaining structure, which can then be completed with very accurate critical dimensions. Using this method, they can now routinely grow lasing VCSELs with Fabry-Perot cavity resonance wavelengths controlled to within 0.5%. 4 figs.

  3. Method for accurate growth of vertical-cavity surface-emitting lasers

    DOEpatents

    Chalmers, Scott A.; Killeen, Kevin P.; Lear, Kevin L.

    1995-01-01

    We report a method for accurate growth of vertical-cavity surface-emitting lasers (VCSELs). The method uses a single reflectivity spectrum measurement to determine the structure of the partially completed VCSEL at a critical point of growth. This information, along with the extracted growth rates, allows imprecisions in growth parameters to be compensated for during growth of the remaining structure, which can then be completed with very accurate critical dimensions. Using this method, we can now routinely grow lasing VCSELs with Fabry-Perot cavity resonance wavelengths controlled to within 0.5%.

  4. Motor equivalence during multi-finger accurate force production

    PubMed Central

    Mattos, Daniela; Schöner, Gregor; Zatsiorsky, Vladimir M.; Latash, Mark L.

    2014-01-01

    We explored stability of multi-finger cyclical accurate force production action by analysis of responses to small perturbations applied to one of the fingers and inter-cycle analysis of variance. Healthy subjects performed two versions of the cyclical task, with and without an explicit target. The “inverse piano” apparatus was used to lift/lower a finger by 1 cm over 0.5 s; the subjects were always instructed to perform the task as accurate as they could at all times. Deviations in the spaces of finger forces and modes (hypothetical commands to individual fingers) were quantified in directions that did not change total force (motor equivalent) and in directions that changed the total force (non-motor equivalent). Motor equivalent deviations started immediately with the perturbation and increased progressively with time. After a sequence of lifting-lowering perturbations leading to the initial conditions, motor equivalent deviations were dominating. These phenomena were less pronounced for analysis performed with respect to the total moment of force with respect to an axis parallel to the forearm/hand. Analysis of inter-cycle variance showed consistently higher variance in a subspace that did not change the total force as compared to the variance that affected total force. We interpret the results as reflections of task-specific stability of the redundant multi-finger system. Large motor equivalent deviations suggest that reactions of the neuromotor system to a perturbation involve large changes of neural commands that do not affect salient performance variables, even during actions with the purpose to correct those salient variables. Consistency of the analyses of motor equivalence and variance analysis provides additional support for the idea of task-specific stability ensured at a neural level. PMID:25344311

  5. Optical Reflectance Measurements for Commonly Used Reflectors

    SciTech Connect

    Janecek, Petr Martin; Moses, William

    2008-06-11

    When simulating light collection in scintillators, modeling the angular distribution of optical light reflectance from surfaces is very important. Since light reflectance is poorly understood, either purely specular or purely diffuse reflectance is generally assumed. In this paper we measure the optical reflectance distribution for eleven commonly used reflectors. A 440 nm, output power stabilized, un-polarized laser is shone onto a reflector at a fixed angle of incidence. The reflected light's angular distribution is measured by an array of silicon photodiodes. The photodiodes are movable to cover 2 pi of solid angle. The light-induced current is, through a multiplexer, read out with a digital multimeter. A LabVIEW program controls the motion of the laser and the photodiode array, the multiplexer, and the data collection. The laser can be positioned at any angle with a position accuracy of 10 arc minutes. Each photodiode subtends 6.3o, and the photodiode array can be positioned at any angle with up to 10 arc minute angular resolution. The dynamic range for the current measurements is 105:1. The measured light reflectance distribution was measured to be specular for several ESR films as well as for aluminum foil, mostly diffuse for polytetrafluoroethylene (PTFE) tape and titanium dioxide paint, and neither specular nor diffuse for Lumirror(R), Melinex(R) and Tyvek(R). Instead, a more complicated light distribution was measured for these three materials.

  6. Leveraging Two Kinect Sensors for Accurate Full-Body Motion Capture

    PubMed Central

    Gao, Zhiquan; Yu, Yao; Zhou, Yu; Du, Sidan

    2015-01-01

    Accurate motion capture plays an important role in sports analysis, the medical field and virtual reality. Current methods for motion capture often suffer from occlusions, which limits the accuracy of their pose estimation. In this paper, we propose a complete system to measure the pose parameters of the human body accurately. Different from previous monocular depth camera systems, we leverage two Kinect sensors to acquire more information about human movements, which ensures that we can still get an accurate estimation even when significant occlusion occurs. Because human motion is temporally constant, we adopt a learning analysis to mine the temporal information across the posture variations. Using this information, we estimate human pose parameters accurately, regardless of rapid movement. Our experimental results show that our system can perform an accurate pose estimation of the human body with the constraint of information from the temporal domain. PMID:26402681

  7. Leveraging Two Kinect Sensors for Accurate Full-Body Motion Capture.

    PubMed

    Gao, Zhiquan; Yu, Yao; Zhou, Yu; Du, Sidan

    2015-01-01

    Accurate motion capture plays an important role in sports analysis, the medical field and virtual reality. Current methods for motion capture often suffer from occlusions, which limits the accuracy of their pose estimation. In this paper, we propose a complete system to measure the pose parameters of the human body accurately. Different from previous monocular depth camera systems, we leverage two Kinect sensors to acquire more information about human movements, which ensures that we can still get an accurate estimation even when significant occlusion occurs. Because human motion is temporally constant, we adopt a learning analysis to mine the temporal information across the posture variations. Using this information, we estimate human pose parameters accurately, regardless of rapid movement. Our experimental results show that our system can perform an accurate pose estimation of the human body with the constraint of information from the temporal domain. PMID:26402681

  8. Higher order accurate partial implicitization: An unconditionally stable fourth-order-accurate explicit numerical technique

    NASA Technical Reports Server (NTRS)

    Graves, R. A., Jr.

    1975-01-01

    The previously obtained second-order-accurate partial implicitization numerical technique used in the solution of fluid dynamic problems was modified with little complication to achieve fourth-order accuracy. The Von Neumann stability analysis demonstrated the unconditional linear stability of the technique. The order of the truncation error was deduced from the Taylor series expansions of the linearized difference equations and was verified by numerical solutions to Burger's equation. For comparison, results were also obtained for Burger's equation using a second-order-accurate partial-implicitization scheme, as well as the fourth-order scheme of Kreiss.

  9. SWIR calibration of Spectralon reflectance factor

    NASA Astrophysics Data System (ADS)

    Georgiev, Georgi T.; Butler, James J.; Cooksey, Catherine; Ding, Leibo; Thome, Kurtis J.

    2011-11-01

    Satellite instruments operating in the reflective solar wavelength region require accurate and precise determination of the Bidirectional Reflectance Factor (BRF) of laboratory-based diffusers used in their pre-flight and on-orbit radiometric calibrations. BRF measurements are required throughout the reflected-solar spectrum from the ultraviolet through the shortwave infrared. Spectralon diffusers are commonly used as a reflectance standard for bidirectional and hemispherical geometries. The Diffuser Calibration Laboratory (DCaL) at NASA's Goddard Space Flight Center is a secondary calibration facility with reflectance measurements traceable to those made by the Spectral Tri-function Automated Reference Reflectometer (STARR) facility at the National Institute of Standards and Technology (NIST). For more than two decades, the DCaL has provided numerous NASA projects with BRF data in the ultraviolet (UV), visible (VIS) and the Near InfraRed (NIR) spectral regions. Presented in this paper are measurements of BRF from 1475 nm to 1625 nm obtained using an indium gallium arsenide detector and a tunable coherent light source. The sample was a 50.8 mm (2 in) diameter, 99% white Spectralon target. The BRF results are discussed and compared to empirically generated data from a model based on NIST certified values of 6°directional-hemispherical spectral reflectance factors from 900 nm to 2500 nm. Employing a new NIST capability for measuring bidirectional reflectance using a cooled, extended InGaAs detector, BRF calibration measurements of the same sample were also made using NIST's STARR from 1475 nm to 1625 nm at an incident angle of 0° and at viewing angle of 45°. The total combined uncertainty for BRF in this ShortWave Infrared (SWIR) range is less than 1%. This measurement capability will evolve into a BRF calibration service in SWIR region in support of NASA remote sensing missions.

  10. Improving light propagation Monte Carlo simulations with accurate 3D modeling of skin tissue

    SciTech Connect

    Paquit, Vincent C; Price, Jeffery R; Meriaudeau, Fabrice; Tobin Jr, Kenneth William

    2008-01-01

    In this paper, we present a 3D light propagation model to simulate multispectral reflectance images of large skin surface areas. In particular, we aim to simulate more accurately the effects of various physiological properties of the skin in the case of subcutaneous vein imaging compared to existing models. Our method combines a Monte Carlo light propagation model, a realistic three-dimensional model of the skin using parametric surfaces and a vision system for data acquisition. We describe our model in detail, present results from the Monte Carlo modeling and compare our results with those obtained with a well established Monte Carlo model and with real skin reflectance images.

  11. Meanings and Reflective Teaching.

    ERIC Educational Resources Information Center

    Stone, Lynda

    Meaning constructs are aspects of a person's cultural worldview. They are those aspects that philosophers often write about as a means by which to make sense of the world. Teachers carry their worldviews and meaning constructs into the classrooms with them. Similarly to teachers, reflective teaching proponents hold meaning constructs that are…

  12. Lights, Camera, Reflection!

    ERIC Educational Resources Information Center

    Mourlam, Daniel

    2013-01-01

    There are many ways to critique teaching, but few are more effective than video. Personal reflection through the use of video allows one to see what really happens in the classrooms--good and bad--and provides a visual path forward for improvement, whether it be in one's teaching, work with a particular student, or learning environment. This…

  13. Reflecting on Data

    ERIC Educational Resources Information Center

    Kraus, Rudolf V.

    2014-01-01

    This article describes a two-day optics laboratory activity that investigates the scientific phenomenon of reflection, which students are generally familiar with but usually have not studied in depth. This investigation can be used on its own or as part of a larger unit on optics. This lesson encourages students to think critically and…

  14. Clinical Linguistics: Conversational Reflections

    ERIC Educational Resources Information Center

    Crystal, David

    2013-01-01

    This is a report of the main points I made in an informal "conversation" with Paul Fletcher and the audience at the 14th ICPLA conference in Cork. The observations arose randomly, as part of an unstructured 1-h Q&A, so they do not provide a systematic account of the subject, but simply reflect the issues which were raised by the conference…

  15. Renew, Reflect, and Refresh

    ERIC Educational Resources Information Center

    Texley, Juliana

    2005-01-01

    Is that the sound of the last bus leaving the schoolyard? Or the staff's collective sigh of relief? School's out. Now it's time to nurture the lifelong learner deep inside with a summer reading list that will allow teachers to renew, reflect, and refresh. The National Science Education Standards reminds us, "Becoming an effective science teacher…

  16. Reflections on Expectations

    ERIC Educational Resources Information Center

    Santini, Joseph

    2014-01-01

    This article describes a teachers reflections on the matter of student expectations. Santini begins with a common understanding of the "Pygmalion effect" from research projects conducted in earlier years that intimated "people's expectations could influence other people in the world around them." In the world of deaf…

  17. Reflections on "La Esperanza"

    ERIC Educational Resources Information Center

    Cortez, Anita

    2007-01-01

    The author was recently asked to reflect on her "educational journey." As far as she can remember she has been hungry to learn. A friend once described her as having "hambres atrasadas," which he described as a kind of "hunger nipping at her heels." It goes back, of course, to her parents: Her father's and her early journeys scavenging the Wyoming…

  18. Reflecting through Peshkin's I's

    ERIC Educational Resources Information Center

    Savage, Jonathan

    2007-01-01

    Reflection is an appropriate way of accounting for professional practice and is a standard way in which one can "become better acquainted with one's own story". Defining "subjectivity" as "the quality of an investigator that affects the results of observational investigation", Peshkin highlights the requirement for any observer of, or participant…

  19. Interactive Reflective Logs

    ERIC Educational Resources Information Center

    Deaton, Cynthia Minchew; Deaton, Benjamin E.; Leland, Katina

    2010-01-01

    The authors created an interactive reflective log (IRL) to provide teachers with an opportunity to use a journal approach to record, evaluate, and communicate student understanding of science concepts. Unlike a traditional journal, the IRL incorporates prompts to encourage students to discuss their understanding of science content and science…

  20. Reflections on 1972

    ERIC Educational Resources Information Center

    Gutierrez, Ramon A.

    2007-01-01

    In this article, the author reflects on the events that took place in the year 1972. The author was a junior at the University of New Mexico back then, refusing to eat or buy grapes and lettuce, picketing grocers who did not carry United Farm Workers of America produce. He and his buddies cast their votes against granting Richard Nixon a second…

  1. Reflection by Porro Prisms

    NASA Astrophysics Data System (ADS)

    Greenslade, Thomas B.

    2010-04-01

    Students all know that reflection from a plane mirror produces an image that is reversed right to left and so cannot be read by anyone but Leonardo da Vinci, who kept his notes in mirror writing. A useful counter-example is the Porro prism, which produces an image that is not reversed.

  2. Ionosphere-reflected propagation

    NASA Technical Reports Server (NTRS)

    Reddy, B. M.

    1979-01-01

    The predictability of those ionospheric parameters relevant to ionosphere-reflected communications is considered along with their optimum utilization. Several excellent original articles and review papers which have been published from time to time dealing with the long term and short term forecasting of ionospheric parameters, radio systems, and modelling needs for ionospheric communications, are covered.

  3. Reflective Database Access Control

    ERIC Educational Resources Information Center

    Olson, Lars E.

    2009-01-01

    "Reflective Database Access Control" (RDBAC) is a model in which a database privilege is expressed as a database query itself, rather than as a static privilege contained in an access control list. RDBAC aids the management of database access controls by improving the expressiveness of policies. However, such policies introduce new interactions…

  4. Modeling Spectralon's Bidirectional Reflectance for In-flight Calibration of Earth-Orbiting Sensors

    NASA Technical Reports Server (NTRS)

    Flasse, Stephane P.; Verstraete, Michel M.; Pinty, Bernard; Bruegge, Carol J.

    1993-01-01

    The in-flight calibration of the EOS Multi-angle Imaging SpectroRadiometer (MISR) will be achieved, in part, by observing deployable Spectralon panels. This material reflects light diffusely, and allows all cameras to view a near constant radiance field. This is particularly true when a panel is illuminated near the surface normal. To meet the challenging MISR calibration requirements, however, very accurate knowledge of the panel reflectance must be known for all utilized angles of illumination, and for all camera and monitoring photodiode view angles. It is believed that model predictions of the panels Bidirectional Reflectance Distribution Function (BRDF) can be used in conjunction with a measurements program to provide the required characterization. This paper describes the results of a model inversion which was conducted using measured Spectralon BRDF data at several illumination angles. Four physical parameters of the material were retrieved, and are available for use with the model to predict reflectance for any arbitrary illumination or view angle. With these data the root mean square difference between the model and the observations is currently of the order of the noise in the data, at about +/- l%. With this success the model will now be used in a variety of future studies, including the development of a measurements test plan, the validation of these data, and the prediction of a new BRDF profile, should the material degrade in space.

  5. An improved six-port technique for measuring complex reflection coefficient

    NASA Astrophysics Data System (ADS)

    Rafal, M. D.

    1980-03-01

    Current realizations of the Six-Port technique for measuring the complex reflection coefficient require accurate information about the system calibration constants. An examination of the sensitivity of the solution of the reflection coefficient to calibration constants is undertaken. An improved set of design specifications is derived based on the sensitivity of the solution and constraints on power measurement accuracy. It has been recognized that the system equations for the Six-Port are an overdetermined set of equations. Previously, this overdeterminedness has not been used to reduce the sensitivity of the solution of the reflection coefficient to variation of the calibration constants. An algorithm is described which makes use of the extra calibration constants. A Fortran program is presented which implements the algorithm. A hardware realization based on the improved set of design specifications is described. The circuit operates at a center frequency of 900 MHz and performs over a 16% band of frequencies without recalibration. Errors in phase measurement for this Six-Port implementation are less than two degrees except at the band edges. Errors in magnitude measurement are less than 10% except for measurements of small values of reflection coefficient magnitude (0.3) for which errors are 20%.

  6. Evaluation of Experimental Data from the Gains Balloon GPS Surface Reflection Instrument

    NASA Technical Reports Server (NTRS)

    Ganoe, George G.; Johnson, Thomas A.; Somero, John Ryan

    2002-01-01

    The GPS Surface Reflection Instrument was integrated as an experiment on the GAINS (Global Airocean IN-situ System) 48-hour balloon mission flown in June 2002. The data collected by similar instruments in the past has been used to measure sea state from which ocean surface winds can be accurately estimated. The GPS signal has also been shown to be reflected from wetland areas and even from subsurface moisture. The current version of the instrument has been redesigned to be more compact, use less power, and withstand a greater variation in environmental conditions than previous versions. This instrument has also incorporated a new data collection mode to track 5 direct satellites (providing a continuous navigation solution) and multiplex the remaining 7 channels to track the reflected signal of the satellite tracked in channel 0. The new software mode has been shown to increase the signal to noise ratio of the collected data and enhance the science return of the instrument. During the GAINS balloon flight over the Northwest US, the instrument measured surface reflections as they were detected over the balloon's ground track. Since ground surface elevations in this area vary widely from the WGS-84 ellipsoid altitude, the instrument software has been modified to incorporate a surface altitude correction based on USGS 30-minute Digital Elevation Models. Information presented will include facts about instrument design goals, data collection methodologies and algorithms, and will focus on results of the science data analyses for the mission.

  7. Evaluation of Experimental Data from the GAINS Balloon GPS Surface Reflection Instrument

    NASA Technical Reports Server (NTRS)

    Gance, George G.; Johnson, Thomas A.

    2004-01-01

    The GPS Surface Reflection Instrument was integrated as an experiment on the GAINS (Global Airocean IN-situ System) 48-hour balloon mission flown in September 2001. The data collected by similar instruments in the past has been used to measure sea state from which ocean surface winds can be accurately estimated. The GPS signal has also been shown to be reflected from wetland areas and even from subsurface moisture. The current version of the instrument has been redesigned to be more compact, use less power, and withstand a greater variation in environmental conditions than previous versions. This instrument has also incorporated a new data collection mode to track 5 direct satellites (providing a continuous navigation solution) and multiplex the remaining 7 channels to track the reflected signal of the satellite tracked in channel 0. The new software mode has been shown to increase the signal to noise ratio of the collected data and enhance the science return of the instrument. During the 48-hour flight over the Northwest US, the instrument will measure surface reflections that can be detected over the balloon's ground track. Since ground surface elevations in this area vary widely from the WGS-84 ellipsoid altitude, the instrument software has been modified to incorporate a surface altitude correction based on USGS 30-minute Digital Elevation Models. Information presented will include facts about instrument design goals, data collection methodologies and algorithms, and results of the science data analyses for the 48-hour mission.

  8. What does reflection from cloud sides tell us about vertical distribution of cloud droplets?

    NASA Technical Reports Server (NTRS)

    Marshak, A.; Kaufman, Yoram; Martins, V.; Zubko, Victor

    2006-01-01

    In order to accurately measure the interaction of clouds with aerosols, we have to resolve the vertical distribution of cloud droplet sizes and determine the temperature of glaciation for clean and polluted clouds. Knowledge of the droplet vertical profile is also essential for understanding precipitation. So far, all existing satellites either measure cloud microphysics only at cloud top (e.g., MODIS) or give a vertical profile of precipitation sized droplets (e.g., Cloudsat). What if one measures cloud microphysical properties in the vertical by retrieving them from the solar and infrared radiation reflected or emitted from cloud sides? This was the idea behind CLAIM-3D (A 3D - cloud aerosol interaction mission) recently proposed by NASA GSFC. This presentation will focus on the interpretation of the radiation reflected from cloud sides. In contrast to plane-parallel approximation, a conventional approach to all current operational retrievals, 3D radiative transfer will be used for interpreting the observed reflectances. As a proof of concept, we will show a few examples of radiation reflected from cloud fields generated by a simple stochastic cloud model with prescribed microphysics. Instead of fixed values of the retrieved effective radii, the probability density functions of droplet size distributions will serve as possible retrievals.

  9. Simple, accurate temperature-measuring instrument

    NASA Technical Reports Server (NTRS)

    Mc Fadin, L. W.

    1970-01-01

    Compact instrument, composed of integrated circuits and a temperature-sensitive platinum resistor, measures temperature over a wide dynamic range. Ultimate accuracy is limited by nonlinearity of the platinum resistor. With proper calibration and current regulation to within 0.01 percent, a measurement accuracy of 0.05 percent can be achieved.

  10. Fair & Accurate Grading for Exceptional Learners

    ERIC Educational Resources Information Center

    Jung, Lee Ann; Guskey, Thomas R.

    2011-01-01

    Despite the many changes in education over the past century, grading and reporting practices have essentially remained the same. In part, this is because few teacher preparation programs offer any guidance on sound grading practices. As a result, most current grading practices are grounded in tradition, rather than research on best practice. In an…

  11. Accurate measurement of the electron beam polarization in JLab Hall A using Compton polarimetry

    SciTech Connect

    S. Escoffier; P.Y. Bertin; M. Brossard; E. Burtin; C. Cavata; N. Colombel; C.W. de Jager; A. Delbart; D. Lhuillier; F. Marie; J. Mitchell; D. Neyret; T. Pussieux

    2005-05-01

    A major advance in accurate electron beam polarization measurement has been achieved at Jlab Hall A with a Compton polarimeter based on a Fabry-Perot cavity photon beam amplifier. At an electron energy of 4.6 GeV and a beam current of 40 uA, a total relative uncertainty of 1.5% is typically achieved within 40 min of data taking. Under the same conditions monitoring of the polarization is accurate at a level of 1%. These unprecedented results make Compton polarimetry an essential tool for modern parity-violation experiments, which require very accurate electron beam polarization measurements.

  12. Measuring Practicum Student Teachers' Reflectivity: The Reflective Pedagogical Thinking Scale

    ERIC Educational Resources Information Center

    Seng, Toh Wah

    2004-01-01

    The purpose of the original study was to investigate practicum student teachers' reflectivity. This paper describes the use of a revised version of the Reflective Pedagogical Thinking Scale (Sparks-Langer, et al., 1990) to measure reflectivity. The original scale was used by the developers to assess reflectivity through a structured interview. The…

  13. Strategy for accurate liver intervention by an optical tracking system

    PubMed Central

    Lin, Qinyong; Yang, Rongqian; Cai, Ken; Guan, Peifeng; Xiao, Weihu; Wu, Xiaoming

    2015-01-01

    Image-guided navigation for radiofrequency ablation of liver tumors requires the accurate guidance of needle insertion into a tumor target. The main challenge of image-guided navigation for radiofrequency ablation of liver tumors is the occurrence of liver deformations caused by respiratory motion. This study reports a strategy of real-time automatic registration to track custom fiducial markers glued onto the surface of a patient’s abdomen to find the respiratory phase, in which the static preoperative CT is performed. Custom fiducial markers are designed. Real-time automatic registration method consists of the automatic localization of custom fiducial markers in the patient and image spaces. The fiducial registration error is calculated in real time and indicates if the current respiratory phase corresponds to the phase of the static preoperative CT. To demonstrate the feasibility of the proposed strategy, a liver simulator is constructed and two volunteers are involved in the preliminary experiments. An ex-vivo porcine liver model is employed to further verify the strategy for liver intervention. Experimental results demonstrate that real-time automatic registration method is rapid, accurate, and feasible for capturing the respiratory phase from which the static preoperative CT anatomical model is generated by tracking the movement of the skin-adhered custom fiducial markers. PMID:26417501

  14. Accurate phylogenetic classification of DNA fragments based onsequence composition

    SciTech Connect

    McHardy, Alice C.; Garcia Martin, Hector; Tsirigos, Aristotelis; Hugenholtz, Philip; Rigoutsos, Isidore

    2006-05-01

    Metagenome studies have retrieved vast amounts of sequenceout of a variety of environments, leading to novel discoveries and greatinsights into the uncultured microbial world. Except for very simplecommunities, diversity makes sequence assembly and analysis a verychallenging problem. To understand the structure a 5 nd function ofmicrobial communities, a taxonomic characterization of the obtainedsequence fragments is highly desirable, yet currently limited mostly tothose sequences that contain phylogenetic marker genes. We show that forclades at the rank of domain down to genus, sequence composition allowsthe very accurate phylogenetic 10 characterization of genomic sequence.We developed a composition-based classifier, PhyloPythia, for de novophylogenetic sequence characterization and have trained it on adata setof 340 genomes. By extensive evaluation experiments we show that themethodis accurate across all taxonomic ranks considered, even forsequences that originate fromnovel organisms and are as short as 1kb.Application to two metagenome datasets 15 obtained from samples ofphosphorus-removing sludge showed that the method allows the accurateclassification at genus level of most sequence fragments from thedominant populations, while at the same time correctly characterizingeven larger parts of the samples at higher taxonomic levels.

  15. An Accurate Temperature Correction Model for Thermocouple Hygrometers 1

    PubMed Central

    Savage, Michael J.; Cass, Alfred; de Jager, James M.

    1982-01-01

    Numerous water relation studies have used thermocouple hygrometers routinely. However, the accurate temperature correction of hygrometer calibration curve slopes seems to have been largely neglected in both psychrometric and dewpoint techniques. In the case of thermocouple psychrometers, two temperature correction models are proposed, each based on measurement of the thermojunction radius and calculation of the theoretical voltage sensitivity to changes in water potential. The first model relies on calibration at a single temperature and the second at two temperatures. Both these models were more accurate than the temperature correction models currently in use for four psychrometers calibrated over a range of temperatures (15-38°C). The model based on calibration at two temperatures is superior to that based on only one calibration. The model proposed for dewpoint hygrometers is similar to that for psychrometers. It is based on the theoretical voltage sensitivity to changes in water potential. Comparison with empirical data from three dewpoint hygrometers calibrated at four different temperatures indicates that these instruments need only be calibrated at, e.g. 25°C, if the calibration slopes are corrected for temperature. PMID:16662241

  16. An accurate temperature correction model for thermocouple hygrometers.

    PubMed

    Savage, M J; Cass, A; de Jager, J M

    1982-02-01

    Numerous water relation studies have used thermocouple hygrometers routinely. However, the accurate temperature correction of hygrometer calibration curve slopes seems to have been largely neglected in both psychrometric and dewpoint techniques.In the case of thermocouple psychrometers, two temperature correction models are proposed, each based on measurement of the thermojunction radius and calculation of the theoretical voltage sensitivity to changes in water potential. The first model relies on calibration at a single temperature and the second at two temperatures. Both these models were more accurate than the temperature correction models currently in use for four psychrometers calibrated over a range of temperatures (15-38 degrees C). The model based on calibration at two temperatures is superior to that based on only one calibration.The model proposed for dewpoint hygrometers is similar to that for psychrometers. It is based on the theoretical voltage sensitivity to changes in water potential. Comparison with empirical data from three dewpoint hygrometers calibrated at four different temperatures indicates that these instruments need only be calibrated at, e.g. 25 degrees C, if the calibration slopes are corrected for temperature. PMID:16662241

  17. Accurate Evaluation Method of Molecular Binding Affinity from Fluctuation Frequency

    NASA Astrophysics Data System (ADS)

    Hoshino, Tyuji; Iwamoto, Koji; Ode, Hirotaka; Ohdomari, Iwao

    2008-05-01

    Exact estimation of the molecular binding affinity is significantly important for drug discovery. The energy calculation is a direct method to compute the strength of the interaction between two molecules. This energetic approach is, however, not accurate enough to evaluate a slight difference in binding affinity when distinguishing a prospective substance from dozens of candidates for medicine. Hence more accurate estimation of drug efficacy in a computer is currently demanded. Previously we proposed a concept of estimating molecular binding affinity, focusing on the fluctuation at an interface between two molecules. The aim of this paper is to demonstrate the compatibility between the proposed computational technique and experimental measurements, through several examples for computer simulations of an association of human immunodeficiency virus type-1 (HIV-1) protease and its inhibitor (an example for a drug-enzyme binding), a complexation of an antigen and its antibody (an example for a protein-protein binding), and a combination of estrogen receptor and its ligand chemicals (an example for a ligand-receptor binding). The proposed affinity estimation has proven to be a promising technique in the advanced stage of the discovery and the design of drugs.

  18. A spectrally accurate algorithm for electromagnetic scattering in three dimensions

    NASA Astrophysics Data System (ADS)

    Ganesh, M.; Hawkins, S.

    2006-09-01

    In this work we develop, implement and analyze a high-order spectrally accurate algorithm for computation of the echo area, and monostatic and bistatic radar cross-section (RCS) of a three dimensional perfectly conducting obstacle through simulation of the time-harmonic electromagnetic waves scattered by the conductor. Our scheme is based on a modified boundary integral formulation (of the Maxwell equations) that is tolerant to basis functions that are not tangential on the conductor surface. We test our algorithm with extensive computational experiments using a variety of three dimensional perfect conductors described in spherical coordinates, including benchmark radar targets such as the metallic NASA almond and ogive. The monostatic RCS measurements for non-convex conductors require hundreds of incident waves (boundary conditions). We demonstrate that the monostatic RCS of small (to medium) sized conductors can be computed using over one thousand incident waves within a few minutes (to a few hours) of CPU time. We compare our results with those obtained using method of moments based industrial standard three dimensional electromagnetic codes CARLOS, CICERO, FE-IE, FERM, and FISC. Finally, we prove the spectrally accurate convergence of our algorithm for computing the surface current, far-field, and RCS values of a class of conductors described globally in spherical coordinates.

  19. Fast and Provably Accurate Bilateral Filtering

    NASA Astrophysics Data System (ADS)

    Chaudhury, Kunal N.; Dabhade, Swapnil D.

    2016-06-01

    The bilateral filter is a non-linear filter that uses a range filter along with a spatial filter to perform edge-preserving smoothing of images. A direct computation of the bilateral filter requires $O(S)$ operations per pixel, where $S$ is the size of the support of the spatial filter. In this paper, we present a fast and provably accurate algorithm for approximating the bilateral filter when the range kernel is Gaussian. In particular, for box and Gaussian spatial filters, the proposed algorithm can cut down the complexity to $O(1)$ per pixel for any arbitrary $S$. The algorithm has a simple implementation involving $N+1$ spatial filterings, where $N$ is the approximation order. We give a detailed analysis of the filtering accuracy that can be achieved by the proposed approximation in relation to the target bilateral filter. This allows us to to estimate the order $N$ required to obtain a given accuracy. We also present comprehensive numerical results to demonstrate that the proposed algorithm is competitive with state-of-the-art methods in terms of speed and accuracy.

  20. Accurate Prediction of Docked Protein Structure Similarity.

    PubMed

    Akbal-Delibas, Bahar; Pomplun, Marc; Haspel, Nurit

    2015-09-01

    One of the major challenges for protein-protein docking methods is to accurately discriminate nativelike structures. The protein docking community agrees on the existence of a relationship between various favorable intermolecular interactions (e.g. Van der Waals, electrostatic, desolvation forces, etc.) and the similarity of a conformation to its native structure. Different docking algorithms often formulate this relationship as a weighted sum of selected terms and calibrate their weights against specific training data to evaluate and rank candidate structures. However, the exact form of this relationship is unknown and the accuracy of such methods is impaired by the pervasiveness of false positives. Unlike the conventional scoring functions, we propose a novel machine learning approach that not only ranks the candidate structures relative to each other but also indicates how similar each candidate is to the native conformation. We trained the AccuRMSD neural network with an extensive dataset using the back-propagation learning algorithm. Our method achieved predicting RMSDs of unbound docked complexes with 0.4Å error margin. PMID:26335807

  1. Accurate lineshape spectroscopy and the Boltzmann constant

    PubMed Central

    Truong, G.-W.; Anstie, J. D.; May, E. F.; Stace, T. M.; Luiten, A. N.

    2015-01-01

    Spectroscopy has an illustrious history delivering serendipitous discoveries and providing a stringent testbed for new physical predictions, including applications from trace materials detection, to understanding the atmospheres of stars and planets, and even constraining cosmological models. Reaching fundamental-noise limits permits optimal extraction of spectroscopic information from an absorption measurement. Here, we demonstrate a quantum-limited spectrometer that delivers high-precision measurements of the absorption lineshape. These measurements yield a very accurate measurement of the excited-state (6P1/2) hyperfine splitting in Cs, and reveals a breakdown in the well-known Voigt spectral profile. We develop a theoretical model that accounts for this breakdown, explaining the observations to within the shot-noise limit. Our model enables us to infer the thermal velocity dispersion of the Cs vapour with an uncertainty of 35 p.p.m. within an hour. This allows us to determine a value for Boltzmann's constant with a precision of 6 p.p.m., and an uncertainty of 71 p.p.m. PMID:26465085

  2. Fast and Provably Accurate Bilateral Filtering.

    PubMed

    Chaudhury, Kunal N; Dabhade, Swapnil D

    2016-06-01

    The bilateral filter is a non-linear filter that uses a range filter along with a spatial filter to perform edge-preserving smoothing of images. A direct computation of the bilateral filter requires O(S) operations per pixel, where S is the size of the support of the spatial filter. In this paper, we present a fast and provably accurate algorithm for approximating the bilateral filter when the range kernel is Gaussian. In particular, for box and Gaussian spatial filters, the proposed algorithm can cut down the complexity to O(1) per pixel for any arbitrary S . The algorithm has a simple implementation involving N+1 spatial filterings, where N is the approximation order. We give a detailed analysis of the filtering accuracy that can be achieved by the proposed approximation in relation to the target bilateral filter. This allows us to estimate the order N required to obtain a given accuracy. We also present comprehensive numerical results to demonstrate that the proposed algorithm is competitive with the state-of-the-art methods in terms of speed and accuracy. PMID:27093722

  3. How Accurate are SuperCOSMOS Positions?

    NASA Astrophysics Data System (ADS)

    Schaefer, Adam; Hunstead, Richard; Johnston, Helen

    2014-02-01

    Optical positions from the SuperCOSMOS Sky Survey have been compared in detail with accurate radio positions that define the second realisation of the International Celestial Reference Frame (ICRF2). The comparison was limited to the IIIaJ plates from the UK/AAO and Oschin (Palomar) Schmidt telescopes. A total of 1 373 ICRF2 sources was used, with the sample restricted to stellar objects brighter than BJ = 20 and Galactic latitudes |b| > 10°. Position differences showed an rms scatter of 0.16 arcsec in right ascension and declination. While overall systematic offsets were < 0.1 arcsec in each hemisphere, both the systematics and scatter were greater in the north.

  4. Accurate adiabatic correction in the hydrogen molecule

    SciTech Connect

    Pachucki, Krzysztof; Komasa, Jacek

    2014-12-14

    A new formalism for the accurate treatment of adiabatic effects in the hydrogen molecule is presented, in which the electronic wave function is expanded in the James-Coolidge basis functions. Systematic increase in the size of the basis set permits estimation of the accuracy. Numerical results for the adiabatic correction to the Born-Oppenheimer interaction energy reveal a relative precision of 10{sup −12} at an arbitrary internuclear distance. Such calculations have been performed for 88 internuclear distances in the range of 0 < R ⩽ 12 bohrs to construct the adiabatic correction potential and to solve the nuclear Schrödinger equation. Finally, the adiabatic correction to the dissociation energies of all rovibrational levels in H{sub 2}, HD, HT, D{sub 2}, DT, and T{sub 2} has been determined. For the ground state of H{sub 2} the estimated precision is 3 × 10{sup −7} cm{sup −1}, which is almost three orders of magnitude higher than that of the best previous result. The achieved accuracy removes the adiabatic contribution from the overall error budget of the present day theoretical predictions for the rovibrational levels.

  5. Accurate adiabatic correction in the hydrogen molecule

    NASA Astrophysics Data System (ADS)

    Pachucki, Krzysztof; Komasa, Jacek

    2014-12-01

    A new formalism for the accurate treatment of adiabatic effects in the hydrogen molecule is presented, in which the electronic wave function is expanded in the James-Coolidge basis functions. Systematic increase in the size of the basis set permits estimation of the accuracy. Numerical results for the adiabatic correction to the Born-Oppenheimer interaction energy reveal a relative precision of 10-12 at an arbitrary internuclear distance. Such calculations have been performed for 88 internuclear distances in the range of 0 < R ⩽ 12 bohrs to construct the adiabatic correction potential and to solve the nuclear Schrödinger equation. Finally, the adiabatic correction to the dissociation energies of all rovibrational levels in H2, HD, HT, D2, DT, and T2 has been determined. For the ground state of H2 the estimated precision is 3 × 10-7 cm-1, which is almost three orders of magnitude higher than that of the best previous result. The achieved accuracy removes the adiabatic contribution from the overall error budget of the present day theoretical predictions for the rovibrational levels.

  6. MEMS accelerometers in accurate mount positioning systems

    NASA Astrophysics Data System (ADS)

    Mészáros, László; Pál, András.; Jaskó, Attila

    2014-07-01

    In order to attain precise, accurate and stateless positioning of telescope mounts we apply microelectromechanical accelerometer systems (also known as MEMS accelerometers). In common practice, feedback from the mount position is provided by electronic, optical or magneto-mechanical systems or via real-time astrometric solution based on the acquired images. Hence, MEMS-based systems are completely independent from these mechanisms. Our goal is to investigate the advantages and challenges of applying such devices and to reach the sub-arcminute range { that is well smaller than the field-of-view of conventional imaging telescope systems. We present how this sub-arcminute accuracy can be achieved with very cheap MEMS sensors. Basically, these sensors yield raw output within an accuracy of a few degrees. We show what kind of calibration procedures could exploit spherical and cylindrical constraints between accelerometer output channels in order to achieve the previously mentioned accuracy level. We also demonstrate how can our implementation be inserted in a telescope control system. Although this attainable precision is less than both the resolution of telescope mount drive mechanics and the accuracy of astrometric solutions, the independent nature of attitude determination could significantly increase the reliability of autonomous or remotely operated astronomical observations.

  7. Accurate, reliable prototype earth horizon sensor head

    NASA Technical Reports Server (NTRS)

    Schwarz, F.; Cohen, H.

    1973-01-01

    The design and performance is described of an accurate and reliable prototype earth sensor head (ARPESH). The ARPESH employs a detection logic 'locator' concept and horizon sensor mechanization which should lead to high accuracy horizon sensing that is minimally degraded by spatial or temporal variations in sensing attitude from a satellite in orbit around the earth at altitudes in the 500 km environ 1,2. An accuracy of horizon location to within 0.7 km has been predicted, independent of meteorological conditions. This corresponds to an error of 0.015 deg-at 500 km altitude. Laboratory evaluation of the sensor indicates that this accuracy is achieved. First, the basic operating principles of ARPESH are described; next, detailed design and construction data is presented and then performance of the sensor under laboratory conditions in which the sensor is installed in a simulator that permits it to scan over a blackbody source against background representing the earth space interface for various equivalent plant temperatures.

  8. Accurate lineshape spectroscopy and the Boltzmann constant.

    PubMed

    Truong, G-W; Anstie, J D; May, E F; Stace, T M; Luiten, A N

    2015-01-01

    Spectroscopy has an illustrious history delivering serendipitous discoveries and providing a stringent testbed for new physical predictions, including applications from trace materials detection, to understanding the atmospheres of stars and planets, and even constraining cosmological models. Reaching fundamental-noise limits permits optimal extraction of spectroscopic information from an absorption measurement. Here, we demonstrate a quantum-limited spectrometer that delivers high-precision measurements of the absorption lineshape. These measurements yield a very accurate measurement of the excited-state (6P1/2) hyperfine splitting in Cs, and reveals a breakdown in the well-known Voigt spectral profile. We develop a theoretical model that accounts for this breakdown, explaining the observations to within the shot-noise limit. Our model enables us to infer the thermal velocity dispersion of the Cs vapour with an uncertainty of 35 p.p.m. within an hour. This allows us to determine a value for Boltzmann's constant with a precision of 6 p.p.m., and an uncertainty of 71 p.p.m. PMID:26465085

  9. Fast and Accurate Exhaled Breath Ammonia Measurement

    PubMed Central

    Solga, Steven F.; Mudalel, Matthew L.; Spacek, Lisa A.; Risby, Terence H.

    2014-01-01

    This exhaled breath ammonia method uses a fast and highly sensitive spectroscopic method known as quartz enhanced photoacoustic spectroscopy (QEPAS) that uses a quantum cascade based laser. The monitor is coupled to a sampler that measures mouth pressure and carbon dioxide. The system is temperature controlled and specifically designed to address the reactivity of this compound. The sampler provides immediate feedback to the subject and the technician on the quality of the breath effort. Together with the quick response time of the monitor, this system is capable of accurately measuring exhaled breath ammonia representative of deep lung systemic levels. Because the system is easy to use and produces real time results, it has enabled experiments to identify factors that influence measurements. For example, mouth rinse and oral pH reproducibly and significantly affect results and therefore must be controlled. Temperature and mode of breathing are other examples. As our understanding of these factors evolves, error is reduced, and clinical studies become more meaningful. This system is very reliable and individual measurements are inexpensive. The sampler is relatively inexpensive and quite portable, but the monitor is neither. This limits options for some clinical studies and provides rational for future innovations. PMID:24962141

  10. Current sheet model

    NASA Technical Reports Server (NTRS)

    1981-01-01

    The model of a rectenna based on the current sheet equivalency of a large planar array is described. The model is mathematically characterized by expression for the fraction of the incident plane wave that is reflected from the sheet. The model is conceptually justified for normal incidence by comparing it to the waveguide model in which evanescent modes, present as beyond and cutoff, correspond to the near field components which become negligible at any significant distance from the antenna array.

  11. Three "Moves" in Enactivist Research: A Reflection

    ERIC Educational Resources Information Center

    Simmt, Elaine; Kieren, Tom

    2015-01-01

    In this paper the authors reflect on the contents of this current issue of ZDM and ask why focus an entire issue on enactivism as a research methodology in mathematics education. In their synthesis of the papers they distinguish and explicate what they observe as three moves in the enactivist research discussed. The first move (and the one that…

  12. AGU leadership reflects back, looks forward

    NASA Astrophysics Data System (ADS)

    Balcerak, Ernie; Buhrman, Joan

    2011-09-01

    AGU president Mike McPhaden, president-elect Carol Finn, and executive director Chris McEntee have served in their current capacities for approximately a year. In this interview, held 18 August after the AGU Council meeting, they reflect back on the year and discuss prospects for the future.

  13. Reflection in Education: A Kantian Epistemology

    ERIC Educational Resources Information Center

    Procee, Henk

    2006-01-01

    As even its defenders admit, reflection in education suffers from a lack of conceptual clarity. In this essay, Henk Procee provides a philosophical analysis of the central concepts in this domain. In the current literature, these concepts are usually taken from the pragmatic school of John Dewey and from critical social theory associated with…

  14. Reflectance spectroscopy and asteroid surface mineralogy

    NASA Technical Reports Server (NTRS)

    Gaffey, Michael J.; Bell, Jeffrey F.; Cruikshank, Dale P.

    1989-01-01

    Information available from reflectance spectroscopy on the surface mineralogy of asteroids is discussed. Current spectral interpretive procedures used in the investigations of asteroid mineralogy are described. Present understanding of the nature and history of asteroids is discussed together with some still unresolved issues such as the source of ordinary chondrites.

  15. A new accurate pill recognition system using imprint information

    NASA Astrophysics Data System (ADS)

    Chen, Zhiyuan; Kamata, Sei-ichiro

    2013-12-01

    Great achievements in modern medicine benefit human beings. Also, it has brought about an explosive growth of pharmaceuticals that current in the market. In daily life, pharmaceuticals sometimes confuse people when they are found unlabeled. In this paper, we propose an automatic pill recognition technique to solve this problem. It functions mainly based on the imprint feature of the pills, which is extracted by proposed MSWT (modified stroke width transform) and described by WSC (weighted shape context). Experiments show that our proposed pill recognition method can reach an accurate rate up to 92.03% within top 5 ranks when trying to classify more than 10 thousand query pill images into around 2000 categories.

  16. Accurate derivative evaluation for any Grad-Shafranov solver

    NASA Astrophysics Data System (ADS)

    Ricketson, L. F.; Cerfon, A. J.; Rachh, M.; Freidberg, J. P.

    2016-01-01

    We present a numerical scheme that can be combined with any fixed boundary finite element based Poisson or Grad-Shafranov solver to compute the first and second partial derivatives of the solution to these equations with the same order of convergence as the solution itself. At the heart of our scheme is an efficient and accurate computation of the Dirichlet to Neumann map through the evaluation of a singular volume integral and the solution to a Fredholm integral equation of the second kind. Our numerical method is particularly useful for magnetic confinement fusion simulations, since it allows the evaluation of quantities such as the magnetic field, the parallel current density and the magnetic curvature with much higher accuracy than has been previously feasible on the affordable coarse grids that are usually implemented.

  17. Radio interferometric measurements for accurate planetary orbiter navigation

    NASA Technical Reports Server (NTRS)

    Poole, S. R.; Ananda, M.; Hildebrand, C. E.

    1979-01-01

    The use of narrowband delta-VLBI to achieve accurate orbit determination is presented by viewing a spacecraft from widely separated stations followed by viewing a nearby quasar from the same stations. Current analysis is examined that establishes the orbit determination accuracy achieved with data arcs spanning up to 3.5 d. Strategies for improving prediction accuracy are given, and the performance of delta-VLBI is compared with conventional radiometric tracking data. It is found that accuracy 'within the fit' is on the order of 0.5 km for data arcs having delta-VLBI on the ends of the arcs and for arc lengths varying from one baseline to 3.5 d. The technique is discussed with reference to the proposed Venus Orbiting Imaging Radar mission.

  18. Toward accurate and fast iris segmentation for iris biometrics.

    PubMed

    He, Zhaofeng; Tan, Tieniu; Sun, Zhenan; Qiu, Xianchao

    2009-09-01

    Iris segmentation is an essential module in iris recognition because it defines the effective image region used for subsequent processing such as feature extraction. Traditional iris segmentation methods often involve an exhaustive search of a large parameter space, which is time consuming and sensitive to noise. To address these problems, this paper presents a novel algorithm for accurate and fast iris segmentation. After efficient reflection removal, an Adaboost-cascade iris detector is first built to extract a rough position of the iris center. Edge points of iris boundaries are then detected, and an elastic model named pulling and pushing is established. Under this model, the center and radius of the circular iris boundaries are iteratively refined in a way driven by the restoring forces of Hooke's law. Furthermore, a smoothing spline-based edge fitting scheme is presented to deal with noncircular iris boundaries. After that, eyelids are localized via edge detection followed by curve fitting. The novelty here is the adoption of a rank filter for noise elimination and a histogram filter for tackling the shape irregularity of eyelids. Finally, eyelashes and shadows are detected via a learned prediction model. This model provides an adaptive threshold for eyelash and shadow detection by analyzing the intensity distributions of different iris regions. Experimental results on three challenging iris image databases demonstrate that the proposed algorithm outperforms state-of-the-art methods in both accuracy and speed. PMID:19574626

  19. Accurate Satellite-Derived Estimates of Tropospheric Ozone Radiative Forcing

    NASA Technical Reports Server (NTRS)

    Joiner, Joanna; Schoeberl, Mark R.; Vasilkov, Alexander P.; Oreopoulos, Lazaros; Platnick, Steven; Livesey, Nathaniel J.; Levelt, Pieternel F.

    2008-01-01

    Estimates of the radiative forcing due to anthropogenically-produced tropospheric O3 are derived primarily from models. Here, we use tropospheric ozone and cloud data from several instruments in the A-train constellation of satellites as well as information from the GEOS-5 Data Assimilation System to accurately estimate the instantaneous radiative forcing from tropospheric O3 for January and July 2005. We improve upon previous estimates of tropospheric ozone mixing ratios from a residual approach using the NASA Earth Observing System (EOS) Aura Ozone Monitoring Instrument (OMI) and Microwave Limb Sounder (MLS) by incorporating cloud pressure information from OMI. Since we cannot distinguish between natural and anthropogenic sources with the satellite data, our estimates reflect the total forcing due to tropospheric O3. We focus specifically on the magnitude and spatial structure of the cloud effect on both the shortand long-wave radiative forcing. The estimates presented here can be used to validate present day O3 radiative forcing produced by models.

  20. Depth from water reflection.

    PubMed

    Linjie Yang; Jianzhuang Liu; Xiaoou Tang

    2015-04-01

    The scene in a water reflection image often exhibits bilateral symmetry. In this paper, we design a framework to reconstruct the depth from a single water reflection image. This problem can be regarded as a special case of two-view stereo vision. It is challenging to obtain correspondences from the real scene and the mirror scene due to their large appearance difference. We first propose an appearance adaptation method to transform the appearance of the mirror scene so that it is much closer to the real scene. We then present a stereo matching algorithm to obtain the disparity map of the real scene. Compared with other depth-from-symmetry work that deals with man-made objects, our algorithm can recover the depth maps of a variety of scenes, where both natural and man-made objects may exist. PMID:25643408

  1. [Current pharmacotherapy in migraine].

    PubMed

    Csépány, Éva; Magyar, Máté; Gyüre, Tamás; Bozsik, György; Ertsey, Csaba

    2015-12-01

    The exact pathomechanism of migraine is still unknown, currently there are no biomarkers for migraine diagnosis, and current animal models reflect only one aspect of migraine, therefore future migraine studies are necessary. The current treatment of migraine (both acute and preventive) is suboptimal. There are no specific preventive drugs for migraine, and current preventatives may become inefficient during long-term use. Triptans are useful abortive drugs, but not effective in some of the patients; severe cardio-or cerebrovascular side effects may occur. Triptans and ergot alkaloids (and also non-specific abortive agents) can cause medication overuse headache. A number of newly synthesized experimental drugs seem to be effective and promising for migraine therapy, but at present our experience with these is limited, therefore further studies are essential. PMID:26727720

  2. Reflective optical imaging system

    DOEpatents

    Shafer, David R.

    2000-01-01

    An optical system compatible with short wavelength (extreme ultraviolet) radiation comprising four reflective elements for projecting a mask image onto a substrate. The four optical elements are characterized in order from object to image as convex, concave, convex and concave mirrors. The optical system is particularly suited for step and scan lithography methods. The invention increases the slit dimensions associated with ringfield scanning optics, improves wafer throughput and allows higher semiconductor device density.

  3. Important Nearby Galaxies without Accurate Distances

    NASA Astrophysics Data System (ADS)

    McQuinn, Kristen

    2014-10-01

    The Spitzer Infrared Nearby Galaxies Survey (SINGS) and its offspring programs (e.g., THINGS, HERACLES, KINGFISH) have resulted in a fundamental change in our view of star formation and the ISM in galaxies, and together they represent the most complete multi-wavelength data set yet assembled for a large sample of nearby galaxies. These great investments of observing time have been dedicated to the goal of understanding the interstellar medium, the star formation process, and, more generally, galactic evolution at the present epoch. Nearby galaxies provide the basis for which we interpret the distant universe, and the SINGS sample represents the best studied nearby galaxies.Accurate distances are fundamental to interpreting observations of galaxies. Surprisingly, many of the SINGS spiral galaxies have numerous distance estimates resulting in confusion. We can rectify this situation for 8 of the SINGS spiral galaxies within 10 Mpc at a very low cost through measurements of the tip of the red giant branch. The proposed observations will provide an accuracy of better than 0.1 in distance modulus. Our sample includes such well known galaxies as M51 (the Whirlpool), M63 (the Sunflower), M104 (the Sombrero), and M74 (the archetypal grand design spiral).We are also proposing coordinated parallel WFC3 UV observations of the central regions of the galaxies, rich with high-mass UV-bright stars. As a secondary science goal we will compare the resolved UV stellar populations with integrated UV emission measurements used in calibrating star formation rates. Our observations will complement the growing HST UV atlas of high resolution images of nearby galaxies.

  4. Towards Accurate Application Characterization for Exascale (APEX)

    SciTech Connect

    Hammond, Simon David

    2015-09-01

    Sandia National Laboratories has been engaged in hardware and software codesign activities for a number of years, indeed, it might be argued that prototyping of clusters as far back as the CPLANT machines and many large capability resources including ASCI Red and RedStorm were examples of codesigned solutions. As the research supporting our codesign activities has moved closer to investigating on-node runtime behavior a nature hunger has grown for detailed analysis of both hardware and algorithm performance from the perspective of low-level operations. The Application Characterization for Exascale (APEX) LDRD was a project concieved of addressing some of these concerns. Primarily the research was to intended to focus on generating accurate and reproducible low-level performance metrics using tools that could scale to production-class code bases. Along side this research was an advocacy and analysis role associated with evaluating tools for production use, working with leading industry vendors to develop and refine solutions required by our code teams and to directly engage with production code developers to form a context for the application analysis and a bridge to the research community within Sandia. On each of these accounts significant progress has been made, particularly, as this report will cover, in the low-level analysis of operations for important classes of algorithms. This report summarizes the development of a collection of tools under the APEX research program and leaves to other SAND and L2 milestone reports the description of codesign progress with Sandia’s production users/developers.

  5. My Reflective Practice as Research.

    ERIC Educational Resources Information Center

    Pereira, Marcia A.

    1999-01-01

    Using Schon's concepts and definition of reflective practice, this article elaborates a model used to analyze the author's own processes of "reflection-in-action" and "reflection-on-action" in teaching first-year architectural students. Emphasizes the importance of the concept of "role-frame" in informing the whole reflective process. (EV)

  6. Reflection Revisited: The Class Collage

    ERIC Educational Resources Information Center

    Sommers, Jeff

    2011-01-01

    Through the regular use of what Donald Schon has termed reflection-in-action and reflection-on-action, students can learn to improve their "reflection-in-presentation," in Kathleen Blake Yancey's term. Students are often asked to do this type of reflection-in-presentation as a capstone to first-year or basic writing courses. However, a number of…

  7. Ultraviolet reflectance properties of asteroids

    NASA Astrophysics Data System (ADS)

    Butterworth, P. S.; Meadows, A. J.

    1985-05-01

    An analysis of the UV spectra of 28 asteroids obtained with the Internal Ultraviolet Explorer (IUE) satellite is presented. The spectra lie within the range 2100-3200 A. The results are examined in terms of both asteroid classification and of current ideas concerning the surface mineralogy of asteroids. For all the asteroids examined, UV reflectivity declines approximately linearly toward shorter wavelengths. In general, the same taxonomic groups are seen in the UV as in the visible and IR, although there is some evidence for asteroids with anomalous UV properties and for UV subclasses within the S class. No mineral absorption features are reported of strength similar to the strongest features in the visible and IR regions, but a number of shallow absorptions do occur and may provide valuable information on the surface composition of many asteroids.

  8. Reflection: moving from a mandatory ritual to meaningful professional development.

    PubMed

    Murdoch-Eaton, Deborah; Sandars, John

    2014-03-01

    Reflection has become established as a key principle underpinning maintenance of standards within professional education and practice. A requirement to evidence reflection within performance review is intended to develop a transformative approach to practice, identify developmental goals, and ultimately, improve healthcare. However, some applications have taken an excessively instrumental approach to the evidencing of reflection, and while they have provided useful templates or framing devices for recording individualistic reflective practice, they potentially have distorted the original intentions. This article revisits the educational theory underpinning the importance of reflection for enhancing performance and considers how to enhance its value within current paediatric practice. PMID:23975720

  9. A simple, sensitive, and accurate alcohol electrode

    SciTech Connect

    Verduyn, C.; Scheffers, W.A.; Van Dijken, J.P.

    1983-04-01

    The construction and performance of an enzyme electrode is described which specifically detects lower primary aliphatic alcohols in aqueous solutions. The electrode consists of a commercial Clark-type oxygen electrode on which alcohol oxidase (E.C. 1.1.3.13) and catalase were immobilized. The decrease in electrode current is linearly proportional to ethanol concentrations betwee 1 and 25 ppm. The response of the electrode remains constant during 400 assays over a period of two weeks. The response time is between 1 and 2 min. Assembly of the electrode takes less than 1 h.

  10. Teaching Reflection Seismic Processing

    NASA Astrophysics Data System (ADS)

    Forel, D.; Benz, T.; Pennington, W. D.

    2004-12-01

    Without pictures, it is difficult to give students a feeling for wave propagation, transmission, and reflection. Even with pictures, wave propagation is still static to many. However, when students use and modify scripts that generate wavefronts and rays through a geologic model that they have modified themselves, we find that students gain a real feeling for wave propagation. To facilitate teaching 2-D seismic reflection data processing (from acquisition through migration) to our undergraduate and graduate Reflection Seismology students, we use Seismic Un*x (SU) software. SU is maintained and distributed by Colorado School of Mines, and it is freely available (at www.cwp.mines.edu/cwpcodes). Our approach includes use of synthetic and real seismic data, processing scripts, and detailed explanation of the scripts. Our real data were provided by Gregory F. Moore of the University of Hawaii. This approach can be used by any school at virtually no expense for either software or data, and can provide students with a sound introduction to techniques used in processing of reflection seismic data. The same software can be used for other purposes, such as research, with no additional expense. Students who have completed a course using SU are well equipped to begin using it for research, as well. Scripts for each processing step are supplied and explained to the students. Our detailed description of the scripts means students do not have to know anything about SU to start. Experience with the Unix operating system is preferable but not necessary -- our notes include Computer Hints to help the beginner work with the Unix operating system. We include several examples of synthetic model building, acquiring shot gathers through synthetic models, sorting shot gathers to CMP gathers, gain, 1-D frequency filtering, f-k filtering, deconvolution, semblance displays and velocity analysis, flattening data (NMO), stacking the CMPs, and migration. We use two real (marine) data sets. One

  11. Method and apparatus for characterizing reflected ultrasonic pulses

    NASA Technical Reports Server (NTRS)

    Yost, William T. (Inventor); Cantrell, John H., Jr. (Inventor)

    1991-01-01

    The invention is a method of and apparatus for characterizing the amplitudes of a sequence of reflected pulses R1, R2, and R3 by converting them into corresponding electric signals E1, E2, and E3 to substantially the same value during each sequence thereby restoring the reflected pulses R1, R2, and R3 to their initial reflection values by timing means, an exponential generator, and a time gain compensator. Envelope and baseline reject circuits permit the display and accurate location of the time spaced sequence of electric signals having substantially the same amplitude on a measurement scale on a suitable video display or oscilloscope.

  12. Accurate Radiometry from Space: An Essential Tool for Climate Studies

    NASA Technical Reports Server (NTRS)

    Fox, Nigel; Kaiser-Weiss, Andrea; Schmutz, Werner; Thome, Kurtis; Young, Dave; Wielicki, Bruce; Winkler, Rainer; Woolliams, Emma

    2011-01-01

    The Earth s climate is undoubtedly changing; however, the time scale, consequences and causal attribution remain the subject of significant debate and uncertainty. Detection of subtle indicators from a background of natural variability requires measurements over a time base of decades. This places severe demands on the instrumentation used, requiring measurements of sufficient accuracy and sensitivity that can allow reliable judgements to be made decades apart. The International System of Units (SI) and the network of National Metrology Institutes were developed to address such requirements. However, ensuring and maintaining SI traceability of sufficient accuracy in instruments orbiting the Earth presents a significant new challenge to the metrology community. This paper highlights some key measurands and applications driving the uncertainty demand of the climate community in the solar reflective domain, e.g. solar irradiances and reflectances/radiances of the Earth. It discusses how meeting these uncertainties facilitate significant improvement in the forecasting abilities of climate models. After discussing the current state of the art, it describes a new satellite mission, called TRUTHS, which enables, for the first time, high-accuracy SI traceability to be established in orbit. The direct use of a primary standard and replication of the terrestrial traceability chain extends the SI into space, in effect realizing a metrology laboratory in space . Keywords: climate change; Earth observation; satellites; radiometry; solar irradiance

  13. Light distribution modulated diffuse reflectance spectroscopy

    PubMed Central

    Huang, Pin-Yuan; Chien, Chun-Yu; Sheu, Chia-Rong; Chen, Yu-Wen; Tseng, Sheng-Hao

    2016-01-01

    Typically, a diffuse reflectance spectroscopy (DRS) system employing a continuous wave light source would need to acquire diffuse reflectances measured at multiple source-detector separations for determining the absorption and reduced scattering coefficients of turbid samples. This results in a multi-fiber probe structure and an indefinite probing depth. Here we present a novel DRS method that can utilize a few diffuse reflectances measured at one source-detector separation for recovering the optical properties of samples. The core of innovation is a liquid crystal (LC) cell whose scattering property can be modulated by the bias voltage. By placing the LC cell between the light source and the sample, the spatial distribution of light in the sample can be varied as the scattering property of the LC cell modulated by the bias voltage, and this would induce intensity variation of the collected diffuse reflectance. From a series of Monte Carlo simulations and phantom measurements, we found that this new light distribution modulated DRS (LDM DRS) system was capable of accurately recover the absorption and scattering coefficients of turbid samples and its probing depth only varied by less than 3% over the full bias voltage variation range. Our results suggest that this LDM DRS platform could be developed to various low-cost, efficient, and compact systems for in-vivo superficial tissue investigation. PMID:27375931

  14. Light distribution modulated diffuse reflectance spectroscopy.

    PubMed

    Huang, Pin-Yuan; Chien, Chun-Yu; Sheu, Chia-Rong; Chen, Yu-Wen; Tseng, Sheng-Hao

    2016-06-01

    Typically, a diffuse reflectance spectroscopy (DRS) system employing a continuous wave light source would need to acquire diffuse reflectances measured at multiple source-detector separations for determining the absorption and reduced scattering coefficients of turbid samples. This results in a multi-fiber probe structure and an indefinite probing depth. Here we present a novel DRS method that can utilize a few diffuse reflectances measured at one source-detector separation for recovering the optical properties of samples. The core of innovation is a liquid crystal (LC) cell whose scattering property can be modulated by the bias voltage. By placing the LC cell between the light source and the sample, the spatial distribution of light in the sample can be varied as the scattering property of the LC cell modulated by the bias voltage, and this would induce intensity variation of the collected diffuse reflectance. From a series of Monte Carlo simulations and phantom measurements, we found that this new light distribution modulated DRS (LDM DRS) system was capable of accurately recover the absorption and scattering coefficients of turbid samples and its probing depth only varied by less than 3% over the full bias voltage variation range. Our results suggest that this LDM DRS platform could be developed to various low-cost, efficient, and compact systems for in-vivo superficial tissue investigation. PMID:27375931

  15. Seismic reflection imaging, accounting for primary and multiple reflections

    NASA Astrophysics Data System (ADS)

    Wapenaar, Kees; van der Neut, Joost; Thorbecke, Jan; Broggini, Filippo; Slob, Evert; Snieder, Roel

    2015-04-01

    Imaging of seismic reflection data is usually based on the assumption that the seismic response consists of primary reflections only. Multiple reflections, i.e. waves that have reflected more than once, are treated as primaries and are imaged at wrong positions. There are two classes of multiple reflections, which we will call surface-related multiples and internal multiples. Surface-related multiples are those multiples that contain at least one reflection at the earth's surface, whereas internal multiples consist of waves that have reflected only at subsurface interfaces. Surface-related multiples are the strongest, but also relatively easy to deal with because the reflecting boundary (the earth's surface) is known. Internal multiples constitute a much more difficult problem for seismic imaging, because the positions and properties of the reflecting interfaces are not known. We are developing reflection imaging methodology which deals with internal multiples. Starting with the Marchenko equation for 1D inverse scattering problems, we derived 3D Marchenko-type equations, which relate reflection data at the surface to Green's functions between virtual sources anywhere in the subsurface and receivers at the surface. Based on these equations, we derived an iterative scheme by which these Green's functions can be retrieved from the reflection data at the surface. This iterative scheme requires an estimate of the direct wave of the Green's functions in a background medium. Note that this is precisely the same information that is also required by standard reflection imaging schemes. However, unlike in standard imaging, our iterative Marchenko scheme retrieves the multiple reflections of the Green's functions from the reflection data at the surface. For this, no knowledge of the positions and properties of the reflecting interfaces is required. Once the full Green's functions are retrieved, reflection imaging can be carried out by which the primaries and multiples are

  16. A Pause for Reflection: Incorporating Reflection into Surgical Training

    PubMed Central

    McGlinn, Evan P.; Chung, Kevin C.

    2014-01-01

    Reflection is an important learning technique for surgeons during their training and is a valuable tool for life-long learning and maintenance of certification to assure competency. Reflection helps individuals to evaluate their performance in the interest of improving their ability to deal with similar experiences in the future. Additionally, reflection can be helpful for established surgeons to continue to improve upon their performance and hone their craft. This article outlines the theoretical role of reflection in the learning process. We will discuss methods for incorporating reflection into training programs, and review the evidence for implementing reflection in surgical training. PMID:25003410

  17. Reflection mass spectrometry technique for monitoring and controlling composition during molecular beam epitaxy

    DOEpatents

    Brennan, T.M.; Hammons, B.E.; Tsao, J.Y.

    1992-12-15

    A method for on-line accurate monitoring and precise control of molecular beam epitaxial growth of Groups III-III-V or Groups III-V-V layers in an advanced semiconductor device incorporates reflection mass spectrometry. The reflection mass spectrometry is responsive to intentional perturbations in molecular fluxes incident on a substrate by accurately measuring the molecular fluxes reflected from the substrate. The reflected flux is extremely sensitive to the state of the growing surface and the measurements obtained enable control of newly forming surfaces that are dynamically changing as a result of growth. 3 figs.

  18. Reflection mass spectrometry technique for monitoring and controlling composition during molecular beam epitaxy

    DOEpatents

    Brennan, Thomas M.; Hammons, B. Eugene; Tsao, Jeffrey Y.

    1992-01-01

    A method for on-line accurate monitoring and precise control of molecular beam epitaxial growth of Groups III-III-V or Groups III-V-V layers in an advanced semiconductor device incorporates reflection mass spectrometry. The reflection mass spectrometry is responsive to intentional perturbations in molecular fluxes incident on a substrate by accurately measuring the molecular fluxes reflected from the substrate. The reflected flux is extremely sensitive to the state of the growing surface and the measurements obtained enable control of newly forming surfaces that are dynamically changing as a result of growth.

  19. Reflectance Sensors: How Stable Are the Values They Measure?

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Reflectance sensors have been shown to be sensitive to the nitrogen status of crops. Systems using these sensors to control real-time variable-rate N fertilizer applications have been developed. For these systems to accurately diagnose the N rate needed, any shift in sensor value over short time per...

  20. Global, long-term surface reflectance records from Landsat

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Global, long-term monitoring of changes in Earth’s land surface requires quantitative comparisons of satellite images acquired under widely varying atmospheric conditions. Although physically based estimates of surface reflectance (SR) ultimately provide the most accurate representation of Earth’s s...

  1. A Fiber-Optic Aircraft Lightning Current Measurement Sensor

    NASA Technical Reports Server (NTRS)

    Nguyen, Truong X.; Ely, Jay J.; Szatkowski, George N.

    2013-01-01

    A fiber-optic current sensor based on the Faraday Effect is developed for aircraft installations. It can measure total lightning current amplitudes and waveforms, including continuing current. Additional benefits include being small, lightweight, non-conducting, safe from electromagnetic interference, and free of hysteresis and saturation. The Faraday Effect causes light polarization to rotate in presence of magnetic field in the direction of light propagation. Measuring the total induced light polarization change yields the total current enclosed. The system operates at 1310nm laser wavelength and can measure approximately 300 A - 300 kA, a 60 dB range. A reflective polarimetric scheme is used, where the light polarization change is measured after a round-trip propagation through the fiber. A two-detector setup measures the two orthogonal polarizations for noise subtraction and improved dynamic range. The current response curve is non-linear and requires a simple spline-fit correction. Effects of high current were achieved in laboratory using combinations of multiple fiber and wire loops. Good result comparisons against reference sensors were achieved up to 300 kA. Accurate measurements on a simulated aircraft fuselage and an internal structure illustrate capabilities that maybe difficult with traditional sensors. Also tested at a commercial lightning test facility from 20 kA to 200 kA, accuracy within 3-10% was achieved even with non-optimum setups.

  2. Force reflection with compliance control

    NASA Technical Reports Server (NTRS)

    Kim, Won S. (Inventor)

    1993-01-01

    Two types of systems for force-reflecting control, which enables high force-reflection gain, are presented: position-error-based force reflection and low-pass-filtered force reflection. Both of the systems are combined with shared compliance control. In the position-error-based class, the position error between the commanded and the actual position of a compliantly controlled robot is used to provide force reflection. In the low-pass-filtered force reflection class, the low-pass-filtered output of the compliance control is used to provide force reflection. The increase in force reflection gain can be more than 10-fold as compared to a conventional high-bandwidth pure force reflection system, when high compliance values are used for the compliance control.

  3. Accurate calculation of field and carrier distributions in doped semiconductors

    NASA Astrophysics Data System (ADS)

    Yang, Wenji; Tang, Jianping; Yu, Hongchun; Wang, Yanguo

    2012-06-01

    We use the numerical squeezing algorithm(NSA) combined with the shooting method to accurately calculate the built-in fields and carrier distributions in doped silicon films (SFs) in the micron and sub-micron thickness range and results are presented in graphical form for variety of doping profiles under different boundary conditions. As a complementary approach, we also present the methods and the results of the inverse problem (IVP) - finding out the doping profile in the SFs for given field distribution. The solution of the IVP provides us the approach to arbitrarily design field distribution in SFs - which is very important for low dimensional (LD) systems and device designing. Further more, the solution of the IVP is both direct and much easy for all the one-, two-, and three-dimensional semiconductor systems. With current efforts focused on the LD physics, knowing of the field and carrier distribution details in the LD systems will facilitate further researches on other aspects and hence the current work provides a platform for those researches.

  4. Nanoparticle Counting: Towards Accurate Determination of the Molar Concentration

    PubMed Central

    Shang, Jing; Gao, Xiaohu

    2014-01-01

    Summary Innovations in nanotechnology have brought tremendous opportunities for the advancement of many research frontiers, ranging from electronics, photonics, energy, to medicine. To maximize the benefits of nano-scaled materials in different devices and systems, precise control of their concentration is a prerequisite. While concentrations of nanoparticles have been provided in other forms (e.g., mass), accurate determination of molar concentration, arguably the most useful one for chemical reactions and applications, has been a major challenge (especially for nanoparticles smaller than 30 nm). Towards this significant yet chronic problem, a variety of strategies are currently under development. Most of these strategies are applicable to a specialized group of nanoparticles due to their restrictions on the composition and size ranges of nanoparticles. As research and uses of nanomaterials being explored in an unprecedented speed, it is necessary to develop universal strategies that are easy to use, and compatible with nanoparticles of different sizes, compositions, and shapes. This review outlines the theories and applications of current strategies to measure nanoparticle molar concentration, discusses the advantages and limitations of these methods, and provides insights into future directions. PMID:25099190

  5. Reflections on Chemical Equations.

    ERIC Educational Resources Information Center

    Gorman, Mel

    1981-01-01

    The issue of how much emphasis balancing chemical equations should have in an introductory chemistry course is discussed. The current heavy emphasis on finishing such equations is viewed as misplaced. (MP)

  6. Current limiters

    SciTech Connect

    Loescher, D.H.; Noren, K.

    1996-09-01

    The current that flows between the electrical test equipment and the nuclear explosive must be limited to safe levels during electrical tests conducted on nuclear explosives at the DOE Pantex facility. The safest way to limit the current is to use batteries that can provide only acceptably low current into a short circuit; unfortunately this is not always possible. When it is not possible, current limiters, along with other design features, are used to limit the current. Three types of current limiters, the fuse blower, the resistor limiter, and the MOSFET-pass-transistor limiters, are used extensively in Pantex test equipment. Detailed failure mode and effects analyses were conducted on these limiters. Two other types of limiters were also analyzed. It was found that there is no best type of limiter that should be used in all applications. The fuse blower has advantages when many circuits must be monitored, a low insertion voltage drop is important, and size and weight must be kept low. However, this limiter has many failure modes that can lead to the loss of over current protection. The resistor limiter is simple and inexpensive, but is normally usable only on circuits for which the nominal current is less than a few tens of milliamperes. The MOSFET limiter can be used on high current circuits, but it has a number of single point failure modes that can lead to a loss of protective action. Because bad component placement or poor wire routing can defeat any limiter, placement and routing must be designed carefully and documented thoroughly.

  7. Reflected Deck Plan, Reflected Roof Plan, Deck Plan Bridgeport ...

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

    Reflected Deck Plan, Reflected Roof Plan, Deck Plan - Bridgeport Covered Bridge, Spanning South Fork of Yuba River at bypassed section of Pleasant Valley Road (originally Virginia Turnpike) in South Yuba River State Park , Bridgeport, Nevada County, CA

  8. Caregiver's Country of Birth Is a Significant Determinant of Accurate Perception of Preschool-Age Children's Weight

    ERIC Educational Resources Information Center

    Natale, Ruby; Uhlhorn, Susan B.; Lopez-Mitnik, Gabriela; Camejo, Stephanie; Englebert, Nicole; Delamater, Alan M.; Messiah, Sarah E.

    2016-01-01

    Background: One in four preschool-age children in the United States are currently overweight or obese. Previous studies have shown that caregivers of this age group often have difficulty accurately recognizing their child's weight status. The purpose of this study was to examine factors associated with accurate/inaccurate perception of child body…

  9. Ionospherically reflected proton whistlers

    NASA Astrophysics Data System (ADS)

    Vavilov, D. I.; Shklyar, D. R.

    2014-12-01

    We present experimental observations and detailed investigation of the variety of proton whistlers that includes transequatorial and ionospherically reflected proton whistlers. The latter have previously been indicated from numerical modeling of spectrograms. The study is based on six-component ELF wave data from the Detection of Electro-Magnetic Emissions Transmitted from Earthquake Regions (DEMETER) satellite which permits to obtain not only spectrograms displaying the power spectral density but also such wave properties as the polarization, wave normal angle, wave refractive index, and normalized parallel component of the Poynting vector. The explanation of various types of proton whistlers is based on the properties of ion cyclotron wave propagation in a multicomponent magnetoplasma, with special consideration of the effect of ion hybrid resonance reflection. Analysis of experimental data is supplemented by numerical modeling of spectrograms that reproduces the main features of experimental ones. As a self-contained result, we provide conclusive experimental evidences that the region illuminated by a lightning stroke in the Earth-ionosphere waveguide may spread over a distance of 4000 km in both hemispheres.

  10. Accurate simulation of optical properties in dyes.

    PubMed

    Jacquemin, Denis; Perpète, Eric A; Ciofini, Ilaria; Adamo, Carlo

    2009-02-17

    Since Antiquity, humans have produced and commercialized dyes. To this day, extraction of natural dyes often requires lengthy and costly procedures. In the 19th century, global markets and new industrial products drove a significant effort to synthesize artificial dyes, characterized by low production costs, huge quantities, and new optical properties (colors). Dyes that encompass classes of molecules absorbing in the UV-visible part of the electromagnetic spectrum now have a wider range of applications, including coloring (textiles, food, paintings), energy production (photovoltaic cells, OLEDs), or pharmaceuticals (diagnostics, drugs). Parallel to the growth in dye applications, researchers have increased their efforts to design and synthesize new dyes to customize absorption and emission properties. In particular, dyes containing one or more metallic centers allow for the construction of fairly sophisticated systems capable of selectively reacting to light of a given wavelength and behaving as molecular devices (photochemical molecular devices, PMDs).Theoretical tools able to predict and interpret the excited-state properties of organic and inorganic dyes allow for an efficient screening of photochemical centers. In this Account, we report recent developments defining a quantitative ab initio protocol (based on time-dependent density functional theory) for modeling dye spectral properties. In particular, we discuss the importance of several parameters, such as the methods used for electronic structure calculations, solvent effects, and statistical treatments. In addition, we illustrate the performance of such simulation tools through case studies. We also comment on current weak points of these methods and ways to improve them. PMID:19113946

  11. Reflecting on Reflective Practice: (Re)Visiting Dewey and Schon

    ERIC Educational Resources Information Center

    Farrell, Thomas S. C.

    2012-01-01

    Since the author began work in reflective practice, at first informally in the late 1970s and then more formally in the mid-1980s, he has always looked at reflective practice as a compass of sorts to guide teachers when they may be seeking direction as to what they are doing in their classrooms. The metaphor of reflection as a compass enables…

  12. Reflection: Journals and Reflective Questions: A Strategy for Professional Learning

    ERIC Educational Resources Information Center

    Clarke, Maggie

    2004-01-01

    Reflective journals have been used widely in teacher education programs to promote reflective thinking (Freidus, 1998; Carter & Francis, 2000; Yost, Senter & Forlenzo-Bailey, 2000). Smyth (1992) advocated that posing a series of questions to be answered in written journals could enhance reflective thinking. It was for this reason that…

  13. Reflection and Non-Reflection of Particle Wavepackets

    ERIC Educational Resources Information Center

    Cox, Timothy; Lekner, John

    2008-01-01

    Exact closed-form solutions of the time-dependent Schrodinger equation are obtained, describing the propagation of wavepackets in the neighbourhood of a potential. Examples given include zero reflection, total reflection and partial reflection of the wavepacket, for the sech[superscript 2]x/a, 1/x[superscript 2] and delta(x) potentials,…

  14. Off-axis reflective optical apparatus

    NASA Technical Reports Server (NTRS)

    Ames, Lawrence L. (Inventor); Leary, David F. (Inventor); Mammini, Paul V. (Inventor)

    2005-01-01

    Embodiments of the present invention are directed to a simple apparatus and a convenient and accurate method of mounting the components to form an off-axis reflective optical apparatus such as a collimator. In one embodiment, an off-axis reflective optical apparatus comprises a mounting block having a ferrule holder support surface and an off-axis reflector support surface which is generally perpendicular to the ferrule holder support surface. An optical reflector is mounted on the off-axis reflector support surface and has a reflected beam centerline. The optical reflector has a conic reflective surface and a conic center. A ferrule holder is mounted on the ferrule holder support surface. The ferrule holder provides a ferrule for coupling to an optical fiber and orienting a fiber tip of the optical fiber along a fiber axis toward the optical reflector. The fiber axis is nonparallel to the reflected beam centerline. Prior to mounting the optical reflector to the off-axis reflector support surface and prior to mounting the ferrule holder to the ferrule holder support surface, the optical reflector is movable on the off-axis reflector surface and the ferrule holder is movable on the ferrule holder support surface to align the conic center of the optical reflector with respect to the fiber tip of the optical fiber, and the apparatus has at least one of the following features: (1) the optical reflector is movable on the off-axis reflector support surface to adjust a focus of the fiber tip with respect to the optical reflector, and (2) the ferrule holder is movable on the ferrule holder support surface to adjust the focus of the fiber tip with respect to the optical reflector.

  15. Magnetic tape lightning current detectors

    NASA Technical Reports Server (NTRS)

    Crouch, K. E.; Jafferis, W.

    1980-01-01

    Development and application tests of a low cost, passive, peak lightning current detector (LCD) found it to provide measurements with accuracies of + or - 5 percent to + or - 10 percent depending on the readout method employed. The LCD uses magnetic audio recording tape to sense the magnitude of the peak magnetic field around a conductor carrying lightning currents. The test results showed that the length of audio tape erased was linearly related to the peak simulated lightning currents in a round conductor. Accuracies of + or - 10 percent were shown for measurements made using a stopwatch readout technique to determine the amount of tape erased by the lightning current. Where more accurate data are desired, the tape is played and the output recorded on a strip chart, oscilloscope, or some other means so that measurements can be made on that recording. Conductor dimensions, tape holder dimensions, and tape formulation must also be considered to obtain a more accurate result.

  16. Renewable liquid reflecting zone plate

    DOEpatents

    Toor, Arthur; Ryutov, Dmitri D.

    2003-12-09

    A renewable liquid reflecting zone plate. Electrodes are operatively connected to a dielectric liquid in a circular or other arrangement to produce a reflecting zone plate. A system for renewing the liquid uses a penetrable substrate.

  17. Reflections on conformal spectra

    NASA Astrophysics Data System (ADS)

    Kim, Hyungrok; Kravchuk, Petr; Ooguri, Hirosi

    2016-04-01

    We use modular invariance and crossing symmetry of conformal field theory to reveal approximate reflection symmetries in the spectral decompositions of the partition function in two dimensions in the limit of large central charge and of the four-point function in any dimension in the limit of large scaling dimensions Δ0 of external operators. We use these symmetries to motivate universal upper bounds on the spectrum and the operator product expansion coefficients, which we then derive by independent techniques. Some of the bounds for four-point functions are valid for finite Δ0 as well as for large Δ0. We discuss a similar symmetry in a large spacetime dimension limit. Finally, we comment on the analogue of the Cardy formula and sparse light spectrum condition for the four-point function.

  18. JFET reflection oscillator

    NASA Technical Reports Server (NTRS)

    Kleinberg, L. L. (Inventor)

    1985-01-01

    A high frequency oscillator circuit is provided using a low cost junction type field effect transistor (T sub 1) with a tuned circuit connected to its gate. The frequency of operation is determined by the tuned circuit and the capacitance reflected from the source to the gate. The transistor is matched to the frequency of operation so that this frequency falls within the roll-off portion of the transistor's transconductance verses frequency curve, preferably somewhat above the 3 db point in frequency. Phase shift necessary to sustain oscillation occurs due to the operation of the transistor in the roll-off portion of the curve and the addition of a phase shifting network (R sub 1, C sub 1) at the source.

  19. Digital infrared fundus reflectance.

    PubMed

    Packer, S; Schneider, K; Lin, H Z; Feldman, M

    1980-06-01

    An infrared sensor was inserted at the film plane of a fundus camera. The signal was visualized on an oscilloscope. In this manner we measured infrared reflectance from the surface of the fundus. The purpose was to characterize choroidal malignant melanomas more reliably than is done with infrared color translation photography. Control lesions were choroidal nevi, metastatic tumors, and disciform macular degenerations. Correlations were made with radioactive phosphorus (32P) uptake, fluorescein angiography, and histopathologic findings. Several cases are presented, one in which this new method of infrared detection was the first diagnostic test to detect the spread of a choroidal melanoma. The simplicity of this technique and its increased accuracy justify the needed further refinements. PMID:7413142

  20. Reflections on Investigating Emotion in Educational Activity Settings

    ERIC Educational Resources Information Center

    Schutz, Paul A.; Hong, Ji Y.; Cross, Dionne I.; Osbon, Jennifer N.

    2006-01-01

    This article represents our current reflections on our approach to inquiry on emotions in education. Our views reflect an eclectic blend of, educational, psychological, and social historical approaches to inquiry on emotion and emotional regulation. In an effort to explicate our approach, we address our working definitions of emotion and emotional…

  1. Tracking daily land surface albedo and reflectance anisotropy with moderate-resolution imaging spectroradiometer (MODIS)

    NASA Astrophysics Data System (ADS)

    Shuai, Yanmin

    A new algorithm provides daily values of land surface albedo and angular reflectance at a 500-m spatial resolution using data from the Moderate Resolution Imaging Spectroradiometer (MODIS) instruments currently in orbit on NASA's Terra and Aqua satellite platforms. To overcome the day-to-day variance in observed surface reflectance induced by differences in view and solar illumination angles, the algorithm uses the RossThickLiSparse-Reciprocal bidirectional reflectance model, which is fitted to all MODIS observations of a 500-m resolution cell acquired during a 16-day moving window. Individual observations are weighted by their quality, observation coverage, and proximity to the production date of interest. Product quality is measured by (1) the root mean square error (RMSE) of observations against the best model fit; and (2) the ability of the angular sampling pattern of the observations at hand to determine reflectance model parameters accurately. A regional analysis of model fits to data from selected MODIS data tiles establishes the bounds of these quality measures for application in the daily algorithm. The algorithm, which is now available to users of direct broadcast satellite data from MODIS, allows daily monitoring of rapid surface radiation and land surface change phenomena such as crop development and forest foliage cycles. In two demonstrations, the daily algorithm captured rapid change in plant phenology. The growth phases of a winter wheat crop, as monitored at the Yucheng agricultural research station in Yucheng, China, matched MODIS daily multispectral reflectance data very well, especially during the flowering and heading stages. The daily algorithm also captured the daily change in autumn leaf color in New England, documenting the ability of the algorithm to work well over large regions with varying degrees of cloud cover and atmospheric conditions. Daily surface albedos measured using ground-based instruments on towers at the agricultural and

  2. Anomalous reflections from the ionosphere

    NASA Astrophysics Data System (ADS)

    Givishvili, G. V.; Leshchenko, L. N.

    2013-09-01

    The existence of anomalous ionospheric reflections was shown on the basis of vertical soundings at the Moskow station. They are observed at heights of 100-200 km. These anomalous reflections are not related to the main Ne( h) ionospheric profile. Morphological characteristics of such reflections are presented: the daily, seasonal, and cyclic dependences of their appearance.

  3. Reflections From a Fresnel Lens

    ERIC Educational Resources Information Center

    Keeports, David

    2005-01-01

    Reflection of light by a convex Fresnel lens gives rise to two distinct images. A highly convex inverted real reflective image forms on the object side of the lens, while an upright virtual reflective image forms on the opposite side of the lens. I describe here a set of laser experiments performed upon a Fresnel lens. These experiments provide…

  4. Structures for Facilitating Student Reflection

    ERIC Educational Resources Information Center

    Grossman, Robert

    2009-01-01

    The goal of this article is to describe a continuum of levels of reflection. It briefly focuses on Deanna Kuhn's research into the development of scientific thinking and Robert Kegan's Object-Subject Theory of Development applied to the problems of inspiring students to be able to reflect. Assignments for improving students' ability to reflect are…

  5. Bi-fluorescence imaging for estimating accurately the nuclear condition of Rhizoctonia spp.

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Aims: To simplify the determination of the nuclear condition of the pathogenic Rhizoctonia, which currently needs to be performed either using two fluorescent dyes, thus is more costly and time-consuming, or using only one fluorescent dye, and thus less accurate. Methods and Results: A red primary ...

  6. Detecting Children's Lies: Are Parents Accurate Judges of Their Own Children's Lies?

    ERIC Educational Resources Information Center

    Talwar, Victoria; Renaud, Sarah-Jane; Conway, Lauryn

    2015-01-01

    The current study investigated whether parents are accurate judges of their own children's lie-telling behavior. Participants included 250 mother-child dyads. Children were between three and 11 years of age. A temptation resistance paradigm was used to elicit a minor transgressive behavior from the children involving peeking at a forbidden toy and…

  7. The U.S. Department of Agriculture Automated Multiple-Pass Method accurately assesses sodium intakes

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Accurate and practical methods to monitor sodium intake of the U.S. population are critical given current sodium reduction strategies. While the gold standard for estimating sodium intake is the 24 hour urine collection, few studies have used this biomarker to evaluate the accuracy of a dietary ins...

  8. Ocean color remote sensing using polarization properties of reflected sunlight

    NASA Technical Reports Server (NTRS)

    Frouin, R.; Pouliquen, E.; Breon, F.-M.

    1994-01-01

    The effects of the atmosphere and surface on sunlight backscattered to space by the ocean may be substantially reduced by using the unpolarized component of reflectance instead of total reflectance. At 450 nm, a wavelength of interest in ocean color remote sensing, and for typical conditions, 45% of the unpolarized reflectance may originate from the water body instead of 20% of the total reflectance, which represents a gain of a factor 2.2 in useful signal for water composition retrieval. The best viewing geometries are adjacent to the glitter region; they correspond to scattering angles around 100 deg, but they may change slightly depending on the polarization characteristics of the aerosols. As aerosol optical thickness increases, the atmosphere becomes less efficient at polarizing sunlight, and the enhancement of the water body contribution to unpolarized reflectance is reduced. Since the perturbing effects are smaller on unpolarized reflectance, at least for some viewing geometries, they may be more easily corrected, leading to a more accurate water-leaving signal and, therefore, more accurate estimates of phytoplankton pigment concentration.

  9. Reflecting on Lab Practices

    ERIC Educational Resources Information Center

    Hunter, Jeffrey C.

    2014-01-01

    The National Science Education Standards (NSES) and the Biological Science Curriculum Study (BSCS) address the need for teachers to move classrooms toward an inquiry approach to learning. Currently, there is movement toward a new structure for science standards, the Next Generation Science Standards (NGSS). In this article, I will take the five…

  10. Reflections on Measuring Thinking, while Listening to Mozart's "Jupiter" Symphony.

    ERIC Educational Resources Information Center

    Wasserman, Selma

    1989-01-01

    Reflects on educators' current preoccupation with assessment of higher order thinking skills. Easy-to-mark, forced-choice, pencil-and-paper tests with single numerical scores may trivialize the wonderful complexity of human capabilities. Includes 17 references. (MLH)

  11. Gravity Currents

    NASA Astrophysics Data System (ADS)

    Simpson, John E.

    1997-03-01

    This book comprehensively describes all aspects of gravity flow, a physical process in the environment that is covered by many disciplines including meteorology, oceanography, the earth sciences and industrial processes. The first edition was very well received, and the author has brought the new edition completely up to date, with much new material. Simpson describes gravity currents with a variety of laboratory experiments, many from his own work. Gravity Currents is a valuable supplementary textbook for undergraduates and a reference work for research workers. The general reader will also find much of interest, since the author clearly describes the physics of flows involved without advanced mathematics, and with numerous photographs and illustrations.

  12. Gravity Currents

    NASA Astrophysics Data System (ADS)

    Simpson, John E.

    1999-11-01

    This book comprehensively describes all aspects of gravity flow, a physical process in the environment that is covered by many disciplines including meteorology, oceanography, the earth sciences and industrial processes. The first edition was very well received, and the author has brought the new edition completely up to date, with much new material. Simpson describes gravity currents with a variety of laboratory experiments, many from his own work. Gravity Currents is a valuable supplementary textbook for undergraduates and a reference work for research workers. The general reader will also find much of interest, since the author clearly describes the physics of flows involved without advanced mathematics, and with numerous photographs and illustrations.

  13. Bidirectional reflectance of zinc oxide

    NASA Technical Reports Server (NTRS)

    Scott, R.

    1973-01-01

    This investigation was undertaken to determine original and useful information about the bidirection reflectance of zinc oxide. The bidirectional reflectance will be studied for the spectra between .25-2.5 microns and the hemisphere above the specimen. The following factors will be considered: (1) surface conditions; (2) specimen preparation; (3) specimen substrate, (4) polarization; (5) depolarization; (6) wavelength; and (7) angles of incident and reflection. The bidirectional reflectance will be checked by experimentally determined angular hemispherical measurements or hemispherical measurements will be used to obtain absolute bidirectional reflectance.

  14. Current Titles

    SciTech Connect

    Various

    2006-06-01

    This booklet is published for those interested in current research being conducted at the National Center for Electron Microscopy. The NCEM is a DOE-designated national user facility and is available at no charge to qualified researchers. Access is controlled by an external steering committee. Interested researchers may contact Jane Cavlina, Administrator, at 510/486-6036.

  15. Passive field reflectance measurements

    NASA Astrophysics Data System (ADS)

    Weber, Christian; Schinca, Daniel C.; Tocho, Jorge O.; Videla, Fabian

    2008-10-01

    The results of reflectance measurements performed with a three-band passive radiometer with independent channels for solar irradiance reference are presented. Comparative operation between the traditional method that uses downward-looking field and reference white panel measurements and the new approach involving duplicated downward- and upward-looking spectral channels (each latter one with its own diffuser) is analyzed. The results indicate that the latter method performs in very good agreement with the standard method and is more suitable for passive sensors under rapidly changing atmospheric conditions (such as clouds, dust, mist, smog and other scatterers), since a more reliable synchronous recording of reference and incident light is achieved. Besides, having separate channels for the reference and the signal allows a better balancing of gains in the amplifiers for each spectral channel. We show the results obtained in the determination of the normalized difference vegetation index (NDVI) corresponding to the period 2004-2007 field experiments concerning weed detection in soybean stubbles and fertilizer level assessment in wheat. The method may be used to refine sensor-based nitrogen fertilizer rate recommendations and to determine suitable zones for herbicide applications.

  16. Venus Highland Anomalous Reflectivity

    NASA Astrophysics Data System (ADS)

    Simpson, Richard A.; Tyler, G. L.; Häusler, B.; Mattei, R.; Patzold, M.

    2009-09-01

    Maxwell Montes was one of several unusually bright areas identified from early Venus radar backscatter observations. Pioneer Venus' orbiting radar associated low emissivity with the bright areas and established a correlation between reflectivity and altitude. Magellan, using an oblique bistatic geometry, showed that the bright surface dielectric constant was not only large but also imaginary -- i.e., the material was conducting, at least near Cleopatra Patera (Pettengill et al., Science, 272, 1996). Venus Express (VEX) repeated Magellan's bistatic observations over Maxwell, using the more conventional circular polarization carried by most spacecraft. Although VEX signal-to-noise ratio was lower than Magellan's, echoes were sufficiently strong to verify the Magellan conclusions near Cleopatra (see J. Geophys. Res., 114, E00B41, doi:10.1029/2008JE003156). Only about 40% of the surface at Cleopatra scatters specularly, opening the Fresnel (specular) interpretation model to question. Elsewhere in Maxwell, the specular percentage may be even lower. Nonetheless, the echo polarization is reversed throughout Maxwell, a result that is consistent with large dielectric constants and difficult to explain without resorting qualitatively (if not quantitatively) to specular models. VEX was scheduled to explore other high altitude regions when its S-Band (13-cm wavelength) radio system failed in late 2006, so further probing of high altitude targets awaits arrival of a new spacecraft.

  17. Peer consultation reflection exercise.

    PubMed Central

    Brown, J. B.; Hogg, W.; Delva, D.; Nanchoff-Glatt, M.; Moore, L.

    1999-01-01

    OBJECTIVE: To explore participants' overall perception of the value of the Peer Consultation Reflection Exercise (PCRE); of barriers and facilitators to participation and learning during a PCRE; and of the transferability of the experience to participants' own settings. DESIGN: This study used the qualitative techniques of key informant interviews and a focus group. SETTING: Focus group and key informant interviews at the 1996 Annual Meeting of the College of Family Physicians of Canada's Section of Teachers. PARTICIPANTS: Family medicine teachers attending a PCRE. METHOD: Five key informant interviews and one focus group composed of five participants were conducted to explore participants' experience of participating and learning during a PCRE. MAIN FINDINGS: Participants viewed the PCRE as a valuable opportunity to interact and learn from colleagues a were especially impressed with the opportunity to listen. Confidentiality and the important role of the facilitator were identified as key components. The greatest perceived barrier was the formal structure of the PCRE. CONCLUSIONS: The PCRE is an innovative strategy for personal and professional development. It could be used in other settings. PMID:10386215

  18. How Accurate Are Transition States from Simulations of Enzymatic Reactions?

    PubMed Central

    2015-01-01

    The rate expression of traditional transition state theory (TST) assumes no recrossing of the transition state (TS) and thermal quasi-equilibrium between the ground state and the TS. Currently, it is not well understood to what extent these assumptions influence the nature of the activated complex obtained in traditional TST-based simulations of processes in the condensed phase in general and in enzymes in particular. Here we scrutinize these assumptions by characterizing the TSs for hydride transfer catalyzed by the enzyme Escherichia coli dihydrofolate reductase obtained using various simulation approaches. Specifically, we compare the TSs obtained with common TST-based methods and a dynamics-based method. Using a recently developed accurate hybrid quantum mechanics/molecular mechanics potential, we find that the TST-based and dynamics-based methods give considerably different TS ensembles. This discrepancy, which could be due equilibrium solvation effects and the nature of the reaction coordinate employed and its motion, raises major questions about how to interpret the TSs determined by common simulation methods. We conclude that further investigation is needed to characterize the impact of various TST assumptions on the TS phase-space ensemble and on the reaction kinetics. PMID:24860275

  19. Accurate measurement of streamwise vortices in low speed aerodynamic flows

    NASA Astrophysics Data System (ADS)

    Waldman, Rye M.; Kudo, Jun; Breuer, Kenneth S.

    2010-11-01

    Low Reynolds number experiments with flapping animals (such as bats and small birds) are of current interest in understanding biological flight mechanics, and due to their application to Micro Air Vehicles (MAVs) which operate in a similar parameter space. Previous PIV wake measurements have described the structures left by bats and birds, and provided insight to the time history of their aerodynamic force generation; however, these studies have faced difficulty drawing quantitative conclusions due to significant experimental challenges associated with the highly three-dimensional and unsteady nature of the flows, and the low wake velocities associated with lifting bodies that only weigh a few grams. This requires the high-speed resolution of small flow features in a large field of view using limited laser energy and finite camera resolution. Cross-stream measurements are further complicated by the high out-of-plane flow which requires thick laser sheets and short interframe times. To quantify and address these challenges we present data from a model study on the wake behind a fixed wing at conditions comparable to those found in biological flight. We present a detailed analysis of the PIV wake measurements, discuss the criteria necessary for accurate measurements, and present a new dual-plane PIV configuration to resolve these issues.

  20. Accurate calculations of bound rovibrational states for argon trimer

    SciTech Connect

    Brandon, Drew; Poirier, Bill

    2014-07-21

    This work presents a comprehensive quantum dynamics calculation of the bound rovibrational eigenstates of argon trimer (Ar{sub 3}), using the ScalIT suite of parallel codes. The Ar{sub 3} rovibrational energy levels are computed to a very high level of accuracy (10{sup −3} cm{sup −1} or better), and up to the highest rotational and vibrational excitations for which bound states exist. For many of these rovibrational states, wavefunctions are also computed. Rare gas clusters such as Ar{sub 3} are interesting because the interatomic interactions manifest through long-range van der Waals forces, rather than through covalent chemical bonding. As a consequence, they exhibit strong Coriolis coupling between the rotational and vibrational degrees of freedom, as well as highly delocalized states, all of which renders accurate quantum dynamical calculation difficult. Moreover, with its (comparatively) deep potential well and heavy masses, Ar{sub 3} is an especially challenging rare gas trimer case. There are a great many rovibrational eigenstates to compute, and a very high density of states. Consequently, very few previous rovibrational state calculations for Ar{sub 3} may be found in the current literature—and only for the lowest-lying rotational excitations.

  1. Accurate stereochemistry for two related 22,26-epiminocholestene derivatives

    SciTech Connect

    Vega-Baez, José Luis; Sandoval-Ramírez, Jesús; Meza-Reyes, Socorro; Montiel-Smith, Sara; Gómez-Calvario, Victor; Bernès, Sylvain

    2008-04-01

    Regioselective opening of ring E of solasodine under various conditions afforded (25R)-22,26-epimino@@cholesta-5,22(N)-di@@ene-3β,16β-diyl diacetate (previously known as 3,16-diacetyl pseudosolasodine B), C{sub 31}H{sub 47}NO{sub 4}, or (22S,25R)-16β-hydr@@oxy-22,26-epimino@@cholesta-5-en-3β-yl acetate (a derivative of the naturally occurring alkaloid oblonginine), C{sub 29}H{sub 47}NO{sub 3}. In both cases, the reactions are carried out with retention of chirality at the C16, C20 and C25 stereogenic centers, which are found to be S, S and R, respectively. Although pseudosolasodine was synthesized 50 years ago, these accurate assignments clarify some controversial points about the actual stereochemistry for these alkaloids. This is of particular importance in the case of oblonginine, since this compound is currently under consideration for the treatment of aphasia arising from apoplexy; the present study defines a diastereoisomerically pure compound for pharmacological studies.

  2. Accurate ab initio vibrational energies of methyl chloride

    SciTech Connect

    Owens, Alec; Yurchenko, Sergei N.; Yachmenev, Andrey; Tennyson, Jonathan; Thiel, Walter

    2015-06-28

    Two new nine-dimensional potential energy surfaces (PESs) have been generated using high-level ab initio theory for the two main isotopologues of methyl chloride, CH{sub 3}{sup 35}Cl and CH{sub 3}{sup 37}Cl. The respective PESs, CBS-35{sup  HL}, and CBS-37{sup  HL}, are based on explicitly correlated coupled cluster calculations with extrapolation to the complete basis set (CBS) limit, and incorporate a range of higher-level (HL) additive energy corrections to account for core-valence electron correlation, higher-order coupled cluster terms, scalar relativistic effects, and diagonal Born-Oppenheimer corrections. Variational calculations of the vibrational energy levels were performed using the computer program TROVE, whose functionality has been extended to handle molecules of the form XY {sub 3}Z. Fully converged energies were obtained by means of a complete vibrational basis set extrapolation. The CBS-35{sup  HL} and CBS-37{sup  HL} PESs reproduce the fundamental term values with root-mean-square errors of 0.75 and 1.00 cm{sup −1}, respectively. An analysis of the combined effect of the HL corrections and CBS extrapolation on the vibrational wavenumbers indicates that both are needed to compute accurate theoretical results for methyl chloride. We believe that it would be extremely challenging to go beyond the accuracy currently achieved for CH{sub 3}Cl without empirical refinement of the respective PESs.

  3. Accurate indel prediction using paired-end short reads

    PubMed Central

    2013-01-01

    Background One of the major open challenges in next generation sequencing (NGS) is the accurate identification of structural variants such as insertions and deletions (indels). Current methods for indel calling assign scores to different types of evidence or counter-evidence for the presence of an indel, such as the number of split read alignments spanning the boundaries of a deletion candidate or reads that map within a putative deletion. Candidates with a score above a manually defined threshold are then predicted to be true indels. As a consequence, structural variants detected in this manner contain many false positives. Results Here, we present a machine learning based method which is able to discover and distinguish true from false indel candidates in order to reduce the false positive rate. Our method identifies indel candidates using a discriminative classifier based on features of split read alignment profiles and trained on true and false indel candidates that were validated by Sanger sequencing. We demonstrate the usefulness of our method with paired-end Illumina reads from 80 genomes of the first phase of the 1001 Genomes Project ( http://www.1001genomes.org) in Arabidopsis thaliana. Conclusion In this work we show that indel classification is a necessary step to reduce the number of false positive candidates. We demonstrate that missing classification may lead to spurious biological interpretations. The software is available at: http://agkb.is.tuebingen.mpg.de/Forschung/SV-M/. PMID:23442375

  4. Accurate ab initio vibrational energies of methyl chloride.

    PubMed

    Owens, Alec; Yurchenko, Sergei N; Yachmenev, Andrey; Tennyson, Jonathan; Thiel, Walter

    2015-06-28

    Two new nine-dimensional potential energy surfaces (PESs) have been generated using high-level ab initio theory for the two main isotopologues of methyl chloride, CH3 (35)Cl and CH3 (37)Cl. The respective PESs, CBS-35( HL), and CBS-37( HL), are based on explicitly correlated coupled cluster calculations with extrapolation to the complete basis set (CBS) limit, and incorporate a range of higher-level (HL) additive energy corrections to account for core-valence electron correlation, higher-order coupled cluster terms, scalar relativistic effects, and diagonal Born-Oppenheimer corrections. Variational calculations of the vibrational energy levels were performed using the computer program TROVE, whose functionality has been extended to handle molecules of the form XY 3Z. Fully converged energies were obtained by means of a complete vibrational basis set extrapolation. The CBS-35( HL) and CBS-37( HL) PESs reproduce the fundamental term values with root-mean-square errors of 0.75 and 1.00 cm(-1), respectively. An analysis of the combined effect of the HL corrections and CBS extrapolation on the vibrational wavenumbers indicates that both are needed to compute accurate theoretical results for methyl chloride. We believe that it would be extremely challenging to go beyond the accuracy currently achieved for CH3Cl without empirical refinement of the respective PESs. PMID:26133427

  5. Accurate ab initio vibrational energies of methyl chloride

    NASA Astrophysics Data System (ADS)

    Owens, Alec; Yurchenko, Sergei N.; Yachmenev, Andrey; Tennyson, Jonathan; Thiel, Walter

    2015-06-01

    Two new nine-dimensional potential energy surfaces (PESs) have been generated using high-level ab initio theory for the two main isotopologues of methyl chloride, CH335Cl and CH337Cl. The respective PESs, CBS-35 HL, and CBS-37 HL, are based on explicitly correlated coupled cluster calculations with extrapolation to the complete basis set (CBS) limit, and incorporate a range of higher-level (HL) additive energy corrections to account for core-valence electron correlation, higher-order coupled cluster terms, scalar relativistic effects, and diagonal Born-Oppenheimer corrections. Variational calculations of the vibrational energy levels were performed using the computer program TROVE, whose functionality has been extended to handle molecules of the form XY 3Z. Fully converged energies were obtained by means of a complete vibrational basis set extrapolation. The CBS-35 HL and CBS-37 HL PESs reproduce the fundamental term values with root-mean-square errors of 0.75 and 1.00 cm-1, respectively. An analysis of the combined effect of the HL corrections and CBS extrapolation on the vibrational wavenumbers indicates that both are needed to compute accurate theoretical results for methyl chloride. We believe that it would be extremely challenging to go beyond the accuracy currently achieved for CH3Cl without empirical refinement of the respective PESs.

  6. Novel Cortical Thickness Pattern for Accurate Detection of Alzheimer's Disease.

    PubMed

    Zheng, Weihao; Yao, Zhijun; Hu, Bin; Gao, Xiang; Cai, Hanshu; Moore, Philip

    2015-01-01

    Brain network occupies an important position in representing abnormalities in Alzheimer's disease (AD) and mild cognitive impairment (MCI). Currently, most studies only focused on morphological features of regions of interest without exploring the interregional alterations. In order to investigate the potential discriminative power of a morphological network in AD diagnosis and to provide supportive evidence on the feasibility of an individual structural network study, we propose a novel approach of extracting the correlative features from magnetic resonance imaging, which consists of a two-step approach for constructing an individual thickness network with low computational complexity. Firstly, multi-distance combination is utilized for accurate evaluation of between-region dissimilarity; and then the dissimilarity is transformed to connectivity via calculation of correlation function. An evaluation of the proposed approach has been conducted with 189 normal controls, 198 MCI subjects, and 163 AD patients using machine learning techniques. Results show that the observed correlative feature suggests significant promotion in classification performance compared with cortical thickness, with accuracy of 89.88% and area of 0.9588 under receiver operating characteristic curve. We further improved the performance by integrating both thickness and apolipoprotein E ɛ4 allele information with correlative features. New achieved accuracies are 92.11% and 79.37% in separating AD from normal controls and AD converters from non-converters, respectively. Differences between using diverse distance measurements and various correlation transformation functions are also discussed to explore an optimal way for network establishment. PMID:26444768

  7. Accurate calculations of bound rovibrational states for argon trimer.

    PubMed

    Brandon, Drew; Poirier, Bill

    2014-07-21

    This work presents a comprehensive quantum dynamics calculation of the bound rovibrational eigenstates of argon trimer (Ar3), using the ScalIT suite of parallel codes. The Ar3 rovibrational energy levels are computed to a very high level of accuracy (10(-3) cm(-1) or better), and up to the highest rotational and vibrational excitations for which bound states exist. For many of these rovibrational states, wavefunctions are also computed. Rare gas clusters such as Ar3 are interesting because the interatomic interactions manifest through long-range van der Waals forces, rather than through covalent chemical bonding. As a consequence, they exhibit strong Coriolis coupling between the rotational and vibrational degrees of freedom, as well as highly delocalized states, all of which renders accurate quantum dynamical calculation difficult. Moreover, with its (comparatively) deep potential well and heavy masses, Ar3 is an especially challenging rare gas trimer case. There are a great many rovibrational eigenstates to compute, and a very high density of states. Consequently, very few previous rovibrational state calculations for Ar3 may be found in the current literature-and only for the lowest-lying rotational excitations. PMID:25053315

  8. Extensive and Highly Accurate Line Lists for Hydrogen Halides

    NASA Astrophysics Data System (ADS)

    Li, G.; Bernath, P. F.; Gordon, I. E.; Rothman, L. S.; Richard, C.; Le Roy, R. J.; Coxon, J. A.; Hajigeorgiou, P.

    2011-06-01

    New dipole moment functions (DMF) for the ground X 1Σ+ electronic states of the hydrogen halides (HF, HCl, HBr, HI) have been obtained using a direct fit approach that fits the best available and appropriately weighted experimental line intensity data for individual ro-vibrational transitions. Combining the newly developed (taking into account the most recent experiments) empirical potential energy functions and the DMFs, line positions and line intensities of the hydrogen halides and their isotopologues have been calculated numerically using program LEVEL. In addition, new semi-empirical algorithms for assigning line-shape parameters for these species have been developed. Using these improvements, new line lists for hydrogen halides were created to update the HITRAN spectroscopic database. These new lists are more accurate and significantly more extensive than those included in the current version of the database (HITRAN2008). R.J. Le Roy, ``LEVEL 8.0, 2007'', University of Waterloo Chemical Physics Research Report CP-663 (2007); see http://leroy.uwaterloo.ca/programs/. L.S. Rothman, I.E. Gordon, A. Barbe, D.C. Benner, P.F. Bernath, et al., ``The HITRAN 2008 Molecular Spectroscopic Database,'' JQSRT 110, 532-572 (2009).

  9. Accurate, Automated Detection of Atrial Fibrillation in Ambulatory Recordings.

    PubMed

    Linker, David T

    2016-06-01

    A highly accurate, automated algorithm would facilitate cost-effective screening for asymptomatic atrial fibrillation. This study analyzed a new algorithm and compared it to existing techniques. The incremental benefit of each step in refinement of the algorithm was measured, and the algorithm was compared to other methods using the Physionet atrial fibrillation and normal sinus rhythm databases. When analyzing segments of 21 RR intervals or less, the algorithm had a significantly higher area under the receiver operating characteristic curve (AUC) than the other algorithms tested. At analysis segment sizes of up to 101 RR intervals, the algorithm continued to have a higher AUC than any of the other methods tested, although the difference from the second best other algorithm was no longer significant, with an AUC of 0.9992 with a 95% confidence interval (CI) of 0.9986-0.9998, vs. 0.9986 (CI 0.9978-0.9994). With identical per-subject sensitivity, per-subject specificity of the current algorithm was superior to the other tested algorithms even at 101 RR intervals, with no false positives (CI 0.0-0.8%) vs. 5.3% false positives for the second best algorithm (CI 3.4-7.9%). The described algorithm shows great promise for automated screening for atrial fibrillation by reducing false positives requiring manual review, while maintaining high sensitivity. PMID:26850411

  10. Accurate inference of local phased ancestry of modern admixed populations.

    PubMed

    Ma, Yamin; Zhao, Jian; Wong, Jian-Syuan; Ma, Li; Li, Wenzhi; Fu, Guoxing; Xu, Wei; Zhang, Kui; Kittles, Rick A; Li, Yun; Song, Qing

    2014-01-01

    Population stratification is a growing concern in genetic-association studies. Averaged ancestry at the genome level (global ancestry) is insufficient for detecting the population substructures and correcting population stratifications in association studies. Local and phase stratification are needed for human genetic studies, but current technologies cannot be applied on the entire genome data due to various technical caveats. Here we developed a novel approach (aMAP, ancestry of Modern Admixed Populations) for inferring local phased ancestry. It took about 3 seconds on a desktop computer to finish a local ancestry analysis for each human genome with 1.4-million SNPs. This method also exhibits the scalability to larger datasets with respect to the number of SNPs, the number of samples, and the size of reference panels. It can detect the lack of the proxy of reference panels. The accuracy was 99.4%. The aMAP software has a capacity for analyzing 6-way admixed individuals. As the biomedical community continues to expand its efforts to increase the representation of diverse populations, and as the number of large whole-genome sequence datasets continues to grow rapidly, there is an increasing demand on rapid and accurate local ancestry analysis in genetics, pharmacogenomics, population genetics, and clinical diagnosis. PMID:25052506

  11. Diffuse reflection imaging of sub-epidermal tissue haematocrit using a simple RGB camera

    NASA Astrophysics Data System (ADS)

    Leahy, Martin J.; O'Doherty, Jim; McNamara, Paul; Henricson, Joakim; Nilsson, Gert E.; Anderson, Chris; Sjoberg, Folke

    2007-05-01

    This paper describes the design and evaluation of a novel easy to use, tissue viability imaging system (TiVi). The system is based on the methods of diffuse reflectance spectroscopy and polarization spectroscopy. The technique has been developed as an alternative to current imaging technology in the area of microcirculation imaging, most notably optical coherence tomography (OCT) and laser Doppler perfusion imaging (LDPI). The system is based on standard digital camera technology, and is sensitive to red blood cells (RBCs) in the microcirculation. Lack of clinical acceptance of both OCT and LDPI fuels the need for an objective, simple, reproducible and portable imaging method that can provide accurate measurements related to stimulus vasoactivity in the microvasculature. The limitations of these technologies are discussed in this paper. Uses of the Tissue Viability system include skin care products, drug development, and assessment spatial and temporal aspects of vasodilation (erythema) and vasoconstriction (blanching).

  12. Mid- Versus Near-Infrared Reflectance Spectroscopy for On-Site Determination of Soil Carbon

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Research has demonstrated that the determination of soil C diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS) is often more accurate and produces more robust calibrations than near-infrared (NIR) reflectance spectroscopy (NIRS) when analyzing ground, dry soils. DRIFTS is also not ...

  13. Directional statistics-based reflectance model for isotropic bidirectional reflectance distribution functions.

    PubMed

    Nishino, Ko; Lombardi, Stephen

    2011-01-01

    We introduce a novel parametric bidirectional reflectance distribution function (BRDF) model that can accurately encode a wide variety of real-world isotropic BRDFs with a small number of parameters. The key observation we make is that a BRDF may be viewed as a statistical distribution on a unit hemisphere. We derive a novel directional statistics distribution, which we refer to as the hemispherical exponential power distribution, and model real-world isotropic BRDFs as mixtures of it. We derive a canonical probabilistic method for estimating the parameters, including the number of components, of this novel directional statistics BRDF model. We show that the model captures the full spectrum of real-world isotropic BRDFs with high accuracy, but a small footprint. We also demonstrate the advantages of the novel BRDF model by showing its use for reflection component separation and for exploring the space of isotropic BRDFs. PMID:21200406

  14. Sampling and uncertainty issues in trending reflectance-based vicarious calibration results

    NASA Astrophysics Data System (ADS)

    Thome, K.

    2005-08-01

    The Remote Sensing Group at the University of Arizona has successfully used various vicarious calibration methods for the absolute radiometric calibration of over 14 separate sensors since 2000. The results of this work implies that the absolute radiometric accuracy of the reflectance-based approach has absolute uncertainties of less than 3% in the visible and near infrared. The precision of the method also appears to have similar uncertainties. This work better quantifies these uncertainties through sensitivity analysis of typical inputs for the Ivanpah and Railroad Valley test sites and comparisons of results from the ALI, ASTER, and ETM+ sensors. The number of data sets collected for these sensors also allows for attempts to determine trends in the radiometric calibration of these sensors. The current work examines the difficulties in trending of reflectance-based results due to temporal sampling issues, site-to-site variability, and accuracy of the method. The results indicate that monthly results over a one-year period at the current accuracy levels may not be sufficient for determining trends in radiometric calibration even though the method provides an accurate absolute radiometric calibration.

  15. Computer programs for eddy-current defect studies

    SciTech Connect

    Pate, J. R.; Dodd, C. V.

    1990-06-01

    Several computer programs to aid in the design of eddy-current tests and probes have been written. The programs, written in Fortran, deal in various ways with the response to defects exhibited by four types of probes: the pancake probe, the reflection probe, the circumferential boreside probe, and the circumferential encircling probe. Programs are included which calculate the impedance or voltage change in a coil due to a defect, which calculate and plot the defect sensitivity factor of a coil, and which invert calculated or experimental readings to obtain the size of a defect. The theory upon which the programs are based is the Burrows point defect theory, and thus the calculations of the programs will be more accurate for small defects. 6 refs., 21 figs.

  16. Measurement of temperature and emissivity of specularly reflecting glowing bodies

    NASA Technical Reports Server (NTRS)

    Hansen, G. P.; Hauge, R. H.; Margrave, J. L.; Krishnan, S.

    1988-01-01

    A new method of measuring the thermodynamic temperature of an object as well as the surface emissivity based on laser reflectivity has been developed. By using rotator analyzer ellipsometry, the light reflected from the sample at a specific angle of incidence can be analyzed for its ellipticity. The normal incidence reflectivity and emissivity are then extracted using standard relations. The thermodynamic temperature of the body is obtained simultaneously by measuring the intensity of emitted light at the same angle of incidence. Room temperature measurements are carried out on selected metals to test the system. Elevated temperature measurements on platinum foils show that this technique is reliable and accurate for monitoring and measuring the temperature and emissivity of specularly reflecting, glowing bodies.

  17. An empirical formula based on Monte Carlo simulation for diffuse reflectance from turbid media

    NASA Astrophysics Data System (ADS)

    Gnanatheepam, Einstein; Aruna, Prakasa Rao; Ganesan, Singaravelu

    2016-03-01

    Diffuse reflectance spectroscopy has been widely used in diagnostic oncology and characterization of laser irradiated tissue. However, still accurate and simple analytical equation does not exist for estimation of diffuse reflectance from turbid media. In this work, a diffuse reflectance lookup table for a range of tissue optical properties was generated using Monte Carlo simulation. Based on the generated Monte Carlo lookup table, an empirical formula for diffuse reflectance was developed using surface fitting method. The variance between the Monte Carlo lookup table surface and the surface obtained from the proposed empirical formula is less than 1%. The proposed empirical formula may be used for modeling of diffuse reflectance from tissue.

  18. Progress Toward Accurate Measurements of Power Consumptions of DBD Plasma Actuators

    NASA Technical Reports Server (NTRS)

    Ashpis, David E.; Laun, Matthew C.; Griebeler, Elmer L.

    2012-01-01

    The accurate measurement of power consumption by Dielectric Barrier Discharge (DBD) plasma actuators is a challenge due to the characteristics of the actuator current signal. Micro-discharges generate high-amplitude, high-frequency current spike transients superimposed on a low-amplitude, low-frequency current. We have used a high-speed digital oscilloscope to measure the actuator power consumption using the Shunt Resistor method and the Monitor Capacitor method. The measurements were performed simultaneously and compared to each other in a time-accurate manner. It was found that low signal-to-noise ratios of the oscilloscopes used, in combination with the high dynamic range of the current spikes, make the Shunt Resistor method inaccurate. An innovative, nonlinear signal compression circuit was applied to the actuator current signal and yielded excellent agreement between the two methods. The paper describes the issues and challenges associated with performing accurate power measurements. It provides insights into the two methods including new insight into the Lissajous curve of the Monitor Capacitor method. Extension to a broad range of parameters and further development of the compression hardware will be performed in future work.

  19. Contribution of Chlorophyll Fluorescence to the Apparent Reflectance of Vegetation

    NASA Technical Reports Server (NTRS)

    Campbell, P. K. Entcheva; Middleton, E. M.; Kim, M. S.

    2007-01-01

    Current strategies for monitoring the physiologic status of terrestrial vegetation rely on remote sensing reflectance (R) measurements, whi ch provide estimates of relative vegetation vigor based primarily on chlorophyll content. Vegetation chlorophyll fluorescence (CF) offers a non-destructive alternative and a more direct approach for diagnosis of vegetation stress before a significant reduction in chlorophyll content has occurred. Thus, monitoring of vegetation vigor based on CF may allow earlier stress detection and more accurate carbon sequestra tion estimates, than is possible using R data alone. However, the observed apparent vegetation reflectance (Ra) in reality includes contrib utions from both the reflected and fluoresced radiation. The aim of t his study is to determine the relative R and CF fractions contributing to Ra from the vegetation in the red to near-infrared region of the spectrum. The practical objectives of the study are to: 1) evaluate t he relationship between CF and R at the foliar level for corn, soybean, maple; and 2) for corn, determine if the relationship established f or healthy (optimal N) vegetation changes under N defiiency. To obtai n generally applicable results, experimental measurements were conducted on unrelated crop and tree species (maple, soybean and corn), unde r controlled conditions and a gradient of inorganic N fertilization l evels. Optical R spectra and actively induced CF emissions were obtained on the same foliar samples, in conjunction with measurements of p hotosynthetic function, pigment levels, and C and N content. The comm on spectral trends or similarities were examined. On average, 10-20% of apparent R at 685 nm was actually due to CF. The spectral trends in steady and maximum F varied significantly, with Fs (especially red) showing higher ability for species and treatment separation. The relative contribution of ChF to R varied significantly among species, with maple emitting much higher F amounts, as

  20. Bidirectional Reflectance of Flat, Optically Thick Particulate Layers: An Efficient Radiative Transfer Solution and Applications to Snow and Soil Surfaces

    NASA Technical Reports Server (NTRS)

    Mishchenko, Michael I.; Dlugach, Janna M.; Yanovitsku, Edgard G.; Zakharova, Nadia T.

    1999-01-01

    We describe a simple and highly efficient and accurate radiative transfer technique for computing bidirectional reflectance of a macroscopically flat scattering layer composed of nonabsorbing or weakly absorbing, arbitrarily shaped, randomly oriented and randomly distributed particles. The layer is assumed to be homogeneous and optically semi-infinite, and the bidirectional reflection function (BRF) is found by a simple iterative solution of the Ambartsumian's nonlinear integral equation. As an exact Solution of the radiative transfer equation, the reflection function thus obtained fully obeys the fundamental physical laws of energy conservation and reciprocity. Since this technique bypasses the computation of the internal radiation field, it is by far the fastest numerical approach available and can be used as an ideal input for Monte Carlo procedures calculating BRFs of scattering layers with macroscopically rough surfaces. Although the effects of packing density and coherent backscattering are currently neglected, they can also be incorporated. The FORTRAN implementation of the technique is available on the World Wide Web at http://ww,,v.giss.nasa.gov/-crmim/brf.html and can be applied to a wide range of remote sensing, engineering, and biophysical problems. We also examine the potential effect of ice crystal shape on the bidirectional reflectance of flat snow surfaces and the applicability of the Henyey-Greenstein phase function and the 6-Eddington approximation in calculations for soil surfaces.

  1. Accurate band-to-band registration of AOTF imaging spectrometer using motion detection technology

    NASA Astrophysics Data System (ADS)

    Zhou, Pengwei; Zhao, Huijie; Jin, Shangzhong; Li, Ningchuan

    2016-05-01

    This paper concerns the problem of platform vibration induced band-to-band misregistration with acousto-optic imaging spectrometer in spaceborne application. Registrating images of different bands formed at different time or different position is difficult, especially for hyperspectral images form acousto-optic tunable filter (AOTF) imaging spectrometer. In this study, a motion detection method is presented using the polychromatic undiffracted beam of AOTF. The factors affecting motion detect accuracy are analyzed theoretically, and calculations show that optical distortion is an easily overlooked factor to achieve accurate band-to-band registration. Hence, a reflective dual-path optical system has been proposed for the first time, with reduction of distortion and chromatic aberration, indicating the potential of higher registration accuracy. Consequently, a spectra restoration experiment using additional motion detect channel is presented for the first time, which shows the accurate spectral image registration capability of this technique.

  2. Appraisal of Artificial Screening Techniques of Tomato to Accurately Reflect Field Performance of the Late Blight Resistance

    PubMed Central

    Nowakowska, Marzena; Nowicki, Marcin; Kłosińska, Urszula; Maciorowski, Robert; Kozik, Elżbieta U.

    2014-01-01

    Late blight (LB) caused by the oomycete Phytophthora infestans continues to thwart global tomato production, while only few resistant cultivars have been introduced locally. In order to gain from the released tomato germplasm with LB resistance, we compared the 5-year field performance of LB resistance in several tomato cultigens, with the results of controlled conditions testing (i.e., detached leaflet/leaf, whole plant). In case of these artificial screening techniques, the effects of plant age and inoculum concentration were additionally considered. In the field trials, LA 1033, L 3707, L 3708 displayed the highest LB resistance, and could be used for cultivar development under Polish conditions. Of the three methods using controlled conditions, the detached leaf and the whole plant tests had the highest correlation with thefield experiments. The plant age effect on LB resistance in tomato reported here, irrespective of the cultigen tested or inoculum concentration used, makes it important to standardize the test parameters when screening for resistance. Our results help show why other reports disagree on LB resistance in tomato. PMID:25279467

  3. How accurately does the VIVO Harvester reflect actual Clinical and Translational Sciences Award–affiliated faculty member publications?*

    PubMed Central

    Eldredge, Jonathan D.; Kroth, Philip J.; Murray-Krezan, Cristina; Hantak, Chad M.; Weagel, Edward F.; Hannigan, Gale G.

    2015-01-01

    Objective: The research tested the accuracy of the VIVO Harvester software in identifying publications authored by faculty members affiliated with a National Institutes of Health Clinical and Translational Sciences Award (CTSA) site. Methods: Health sciences librarians created “gold standard” lists of references for the years 2001 to 2011 from PubMed for twenty-five randomly selected investigators from one CTSA site. These gold standard lists were compared to the same twenty-five investigators' reference lists produced by VIVO Harvester. The authors subjected the discrepancies between the lists to sensitivity and specificity analyses. Results: The VIVO Harvester correctly identified only about 65% of the total eligible PubMed references for the years 2001–2011 for the CTSA-affiliated investigators. The identified references produced by VIVO Harvester were precise yet incomplete. The sensitivity rate was 0.65, and the specificity rate was 1.00. Conclusion: While the references produced by VIVO Harvester could be confirmed in PubMed, the VIVO Harvester retrieved only two-thirds of the required references from PubMed. National Institutes of Health CTSA sites will need to supplement VIVO Harvester–produced references with the expert searching skills of health sciences librarians. Implications: Health sciences librarians with searching skills need to alert their CTSA sites about these deficiencies and offer their skills to advance their sites' missions. PMID:25552940

  4. POLARIZED LIGHT REFLECTED AND TRANSMITTED BY THICK RAYLEIGH SCATTERING ATMOSPHERES

    SciTech Connect

    Natraj, Vijay; Hovenier, J. W.

    2012-03-20

    Accurate values for the intensity and polarization of light reflected and transmitted by optically thick Rayleigh scattering atmospheres with a Lambert surface underneath are presented. A recently reported new method for solving integral equations describing Chandrasekhar's X- and Y-functions is used. The results have been validated using various tests and techniques, including the doubling-adding method, and are accurate to within one unit in the eighth decimal place. Tables are stored electronically and expected to be useful as benchmark results for the (exo)planetary science and astrophysics communities. Asymptotic expressions to obtain Stokes parameters for a thick layer from those of a semi-infinite atmosphere are also provided.

  5. Planar Reflection of Detonations Waves

    NASA Astrophysics Data System (ADS)

    Damazo, Jason; Shepherd, Joseph

    2012-11-01

    An experimental study examining normally reflected gaseous detonation waves is undertaken so that the physics of reflected detonations may be understood. Focused schlieren visualization is used to describe the boundary layer development behind the incident detonation wave and the nature of the reflected shock wave. Reflected shock wave bifurcation-which has received extensive study as it pertains to shock tube performance-is predicted by classical bifurcation theory, but is not observed in the present study for undiluted hydrogen-oxygen and ethylene-oxygen detonation waves. Pressure and thermocouple gauges are installed in the floor of the detonation tube so as to examine both the wall pressure and heat flux. From the pressure results, we observe an inconsistency between the measured reflected shock speed and the measured reflected shock strength with one dimensional flow predictions confirming earlier experiments performed in our laboratory. This research is sponsored by the DHS through the University of Rhode Island, Center of Excellence for Explosives Detection.

  6. Baffle system employing reflective surfaces

    NASA Astrophysics Data System (ADS)

    Linlor, W. I.

    1983-12-01

    Reflective baffles are proposed to reject off-axis light entering a telescope. Toroidal surfaces and adjacent cones are positioned so that off-axis rays make multiple reflections between these two surfaces. Meridional rays are reflected approximately parallel to the entering direction. Skew rays are reflected obliquely, but leave the telescope aperture. The range of incident angles for which these reflections are obtained is approximately 45 deg. A system is described that is designed specifically for the Space Shuttle Infrared Telescope Facility (SIRTF). Because of its reflective properties, the proposed baffle system rejects about 90 deg of the heat load from the SIRTF sunshade that would be absorbed in systems of conventional black baffles.

  7. Variable area light reflecting assembly

    DOEpatents

    Howard, T.C.

    1986-12-23

    Device is described for tracking daylight and projecting it into a building. The device tracks the sun and automatically adjusts both the orientation and area of the reflecting surface. The device may be mounted in either a wall or roof of a building. Additionally, multiple devices may be employed in a light shaft in a building, providing daylight to several different floors. The preferred embodiment employs a thin reflective film as the reflecting device. One edge of the reflective film is fixed, and the opposite end is attached to a spring-loaded take-up roller. As the sun moves across the sky, the take-up roller automatically adjusts the angle and surface area of the film. Additionally, louvers may be mounted at the light entrance to the device to reflect incoming daylight in an angle perpendicular to the device to provide maximum reflective capability when daylight enters the device at non-perpendicular angles. 9 figs.

  8. Variable area light reflecting assembly

    DOEpatents

    Howard, Thomas C.

    1986-01-01

    Device for tracking daylight and projecting it into a building. The device tracks the sun and automatically adjusts both the orientation and area of the reflecting surface. The device may be mounted in either a wall or roof of a building. Additionally, multiple devices may be employed in a light shaft in a building, providing daylight to several different floors. The preferred embodiment employs a thin reflective film as the reflecting device. One edge of the reflective film is fixed, and the opposite end is attached to a spring-loaded take-up roller. As the sun moves across the sky, the take-up roller automatically adjusts the angle and surface area of the film. Additionally, louvers may be mounted at the light entrance to the device to reflect incoming daylight in an angle perpendicular to the device to provide maximum reflective capability when daylight enters the device at non-perpendicular angles.

  9. Current titles

    SciTech Connect

    1995-07-01

    This booklet is published for those interested in current research being conducted at the National Center for Electron Microscopy. The NCEM is a DOE-designated national user facility and is available at no charge to qualified researchers. Access is controlled by an external steering committee. Interested researchers may contact Gretchen Hermes at (510) 486-5006 or address below for a User`s Guide. Copies of available papers can be ordered from: Theda Crawford National Center for Electron Microscopy, Lawrence Berkeley Laboratory, One Cyclotron Rd., MS72, Berkeley, California, USA 94720.

  10. High-frequency techniques for RCS prediction of plate geometries and a physical optics/equivalent currents model for the RCS of trihedral corner reflectors, parts 1 and 2

    NASA Technical Reports Server (NTRS)

    Balanis, Constantine A.; Polka, Lesley A.; Polycarpou, Anastasis C.

    1994-01-01

    Formulations for scattering from the coated plate and the coated dihedral corner reflector are included. A coated plate model based upon the Uniform Theory of Diffraction (UTD) for impedance wedges was presented in the last report. In order to resolve inaccuracies and discontinuities in the predicted patterns using the UTD-based model, an improved model that uses more accurate diffraction coefficients is presented. A Physical Optics (PO) model for the coated dihedral corner reflector is presented as an intermediary step in developing a high-frequency model for this structure. The PO model is based upon the reflection coefficients for a metal-backed lossy material. Preliminary PO results for the dihedral corner reflector suggest that, in addition to being much faster computationally, this model may be more accurate than existing moment method (MM) models. An improved Physical Optics (PO)/Equivalent Currents model for modeling the Radar Cross Section (RCS) of both square and triangular, perfectly conducting, trihedral corner reflectors is presented. The new model uses the PO approximation at each reflection for the first- and second-order reflection terms. For the third-order reflection terms, a Geometrical Optics (GO) approximation is used for the first reflection; and PO approximations are used for the remaining reflections. The previously reported model used GO for all reflections except the terminating reflection. Using PO for most of the reflections results in a computationally slower model because many integrations must be performed numerically, but the advantage is that the predicted RCS using the new model is much more accurate. Comparisons between the two PO models, Finite-Difference Time-Domain (FDTD) and experimental data are presented for validation of the new model.

  11. Reflectional transformation for structural stiffness

    SciTech Connect

    Vashi, K.M.

    1990-01-01

    This paper presents a structural reflection-related transformation for structural stiffness. The stiffness transformation addresses reflection of a structure about any of the three coordinate planes and renders the desired stiffness matrix using a stiffness matrix for the same structure before reflection. This transformation is elegant and simple, provides an efficient and technically rigorous approach to derive the required stiffness matrix without structural remodeling, and can be readily programmed to quickly perform the required matrix manipulations. 2 figs.

  12. Atlas of soil reflectance properties

    NASA Technical Reports Server (NTRS)

    Stoner, E. R.; Baumgardner, M. F.; Biehl, L. L.; Robinson, B. F.

    1979-01-01

    A compendium of soil spectral reflectance curves together with soil test results and site information is presented in an abbreviated manner listing those soil properties most important in influencing soil reflectance. Results are presented for 251 soils from 39 states and Brazil. A narrative key describes relationships between soil parameters and reflectance curves. All soils are classified according to the U.S. soil taxonomy and soil series name for ease of identification.

  13. On the distribution of seismic reflection coefficients and seismic amplitudes

    SciTech Connect

    Painter, S.; Paterson, L.; Beresford, G.

    1995-07-01

    Reflection coefficient sequences from 14 wells in Australia have a statistical character consistent with a non-Gaussian scaling noise model based on the Levy-stable family of probability distributions. Experimental histograms of reflection coefficients are accurately approximated by symmetric Levy-stable probability density functions with Levy index between 0.99 and 1.43. These distributions have the same canonical role in mathematical statistics as the Gaussian distribution, but they have slowly decaying tails and infinite moments. The distribution of reflection coefficients is independent of the spatial scale (statistically self-similar), and the reflection coefficient sequences have long-range dependence. These results suggest that the logarithm of seismic impedance can be modeled accurately using fractional Levy motion, which is a generalization of fractional Brownian motion. Synthetic seismograms produced from the authors` model for the reflection coefficients also have Levy-stable distributions. These isolations include transmission losses, the effects of reverberations, and the loss of resolution caused by band-limited wavelets, and suggest that actual seismic amplitudes with sufficient signal-to-noise ratio should also have a Levy-stable distribution. This prediction is verified using post-stack seismic data acquired in the Timor Sea and in the continental USA. However, prestack seismic amplitudes from the Timor Sea are nearly Gaussian. They attribute the difference between prestack and poststack data to the high level of measurement noise in the prestack data.

  14. The Basingstoke Orthopaedic Database: a high quality accurate information system for audit.

    PubMed

    Barlow, I W; Flynn, N A; Britton, J M

    1994-11-01

    The accuracy of a computerised audit system custom produced for the Orthopaedic Department has been validated by comparison with operating theatre records and patients' case notes. The study revealed only 2.5 per cent missed entries; of the recorded entries information regarding the nature of the operation was found to be 92.5 per cent complete and 98 per cent accurate. The high percentage accuracy reflects the high degree of medical input in operation of the system. The Basingstoke Orthopaedic Database is flexible, cheap and easy to maintain. Data is stored in a form that is readily applicable to standard software packages. PMID:7598401

  15. Signals for specular Andreev reflection.

    PubMed

    Zhang, Qingyun; Fu, Deyi; Wang, Baigeng; Zhang, R; Xing, D Y

    2008-07-25

    We report a theoretical investigation of the spin-dependent Andreev reflection at the interface of a graphene-based ferromagnet/superconductor junction. It is found that the ferromagnetic exchange interaction in the ferromagnet can suppress Andreev retroreflection but enhance the specular Andreev reflection. There is a transition between the specular Andreev reflection and Andreev retroreflection at which the shot noise vanishes and the Fano factor has a universal value. The present work provides a new method of detecting the specular Andreev reflection, which can be experimentally tested within the present-day technique. PMID:18764360

  16. Weak-shock reflection factors

    SciTech Connect

    Reichenbach, H.; Kuhl, A.L.

    1993-09-07

    The purpose of this paper is to compare reflection factors for weak shocks from various surfaces, and to focus attention on some unsolved questions. Three different cases are considered: square-wave planar shock reflection from wedges; square-wave planar shock reflection from cylinders; and spherical blast wave reflection from a planar surface. We restrict ourselves to weak shocks. Shocks with a Mach number of M{sub O} < 1.56 in air or with an overpressure of {Delta}{sub PI} < 25 psi (1.66 bar) under normal ambient conditions are called weak.

  17. Reflections on stimulus control.

    PubMed

    Sidman, Murray

    2008-01-01

    The topic of stimulus control is too broad and complex to be traceable here. It would probably take a two-semester course to cover just the highlights of that field's evolution. The more restricted topic of equivalence relations has itself become so broad that even an introductory summary requires more time than we have available. An examination of relations between equivalence and the more general topic of stimulus control, however, may reveal characteristics of both the larger and the more limited field that have not been generally discussed. Consideration of these features may in turn foster future developments within each area. I speak, of course, about aspects of stimulus control that my own experiences have made salient to me; others would surely emphasize different characteristics of the field. It is my hope that cooperative interactions among researchers and theorists who approach stimulus control from different directions will become more common than is currently typical. PMID:22478506

  18. Specular Reflection and Diffuse Reflectance Spectroscopy of Soils

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Studies on the occurrence and effects of specular reflection in mid-infrared spectra of soils have shown that distortions due to specular reflection occur for both organic (humic acid) and non-organic fractions (carbonates, silica, ashed fraction of soil). The results demonstrated explain why the s...

  19. Postgraduate Education to Support Organisation Change: A Reflection on Reflection

    ERIC Educational Resources Information Center

    Stewart, Jim; Keegan, Anne; Stevens, Pam

    2008-01-01

    Purpose: This paper aims to explore how teaching and assessing reflective learning skills can support postgraduate practitioners studying organisational change and explores the challenges for tutors in assessing these journals. Design/methodology/approach: Assessment criteria were developed from the literature on reflective practice and…

  20. Studies of the Reflection, Refraction and Internal Reflection of Light

    ERIC Educational Resources Information Center

    Lanchester, P. C.

    2014-01-01

    An inexpensive apparatus and associated experiments are described for studying the basic laws of reflection and refraction of light at an air-glass interface, and multiple internal reflections within a glass block. In order to motivate students and encourage their active participation, a novel technique is described for determining the refractive…

  1. Reflective Practice Interventions: Raising Levels of Reflective Judgment

    ERIC Educational Resources Information Center

    Friedman, Audrey; Schoen, Lea

    2009-01-01

    Reflective practice is a major focus of teacher preparation programs (Cochran-Smith & Lytle, 1992; Putnam & Borko, 2000; Zeichner, 1986; Zeichner & Liston, 1987), yet Zeichner (1986) asserts that developing reflective practice in preservice teachers has focused primarily on short-term, less systematic interventions and that interventions must be…

  2. Embodied Reflection and the Epistemology of Reflective Practice

    ERIC Educational Resources Information Center

    Kinsella, Elizabeth Anne

    2007-01-01

    Donald Schon's theory of reflective practice has been extensively referred to and has had enormous impact in education and related fields. Nonetheless, there continues to be tremendous conceptual and practical confusion surrounding interpretations of reflective practice and philosophical assumptions underlying the theory. In this paper, I argue…

  3. Acoustic Immittance, Absorbance, and Reflectance in the Human Ear Canal

    PubMed Central

    Rosowski, John J.; Wilber, Laura Ann

    2015-01-01

    Ear canal measurements of acoustic immittance (a term that groups impedance and its inverse, admittance) and the related quantities of acoustic reflectance and power absorbance have been used to assess auditory function and aid in the differential diagnosis of conductive hearing loss for over 50 years. The change in such quantities after stimulation of the acoustic reflex also has been used in diagnosis. In this article, we define these quantities, describe how they are commonly measured, and discuss appropriate calibration procedures and standards necessary for accurate immittance/reflectance measurements.

  4. 78 FR 34604 - Submitting Complete and Accurate Information

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-06-10

    ... COMMISSION 10 CFR Part 50 Submitting Complete and Accurate Information AGENCY: Nuclear Regulatory Commission... accurate information as would a licensee or an applicant for a license.'' DATES: Submit comments by August... may submit comments by any of the following methods (unless this document describes a different...

  5. Tube dimpling tool assures accurate dip-brazed joints

    NASA Technical Reports Server (NTRS)

    Beuyukian, C. S.; Heisman, R. M.

    1968-01-01

    Portable, hand-held dimpling tool assures accurate brazed joints between tubes of different diameters. Prior to brazing, the tool performs precise dimpling and nipple forming and also provides control and accurate measuring of the height of nipples and depth of dimples so formed.

  6. 31 CFR 205.24 - How are accurate estimates maintained?

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 31 Money and Finance: Treasury 2 2010-07-01 2010-07-01 false How are accurate estimates maintained... Treasury-State Agreement § 205.24 How are accurate estimates maintained? (a) If a State has knowledge that an estimate does not reasonably correspond to the State's cash needs for a Federal assistance...

  7. Measuring accurate body parameters of dressed humans with large-scale motion using a Kinect sensor.

    PubMed

    Xu, Huanghao; Yu, Yao; Zhou, Yu; Li, Yang; Du, Sidan

    2013-01-01

    Non-contact human body measurement plays an important role in surveillance, physical healthcare, on-line business and virtual fitting. Current methods for measuring the human body without physical contact usually cannot handle humans wearing clothes, which limits their applicability in public environments. In this paper, we propose an effective solution that can measure accurate parameters of the human body with large-scale motion from a Kinect sensor, assuming that the people are wearing clothes. Because motion can drive clothes attached to the human body loosely or tightly, we adopt a space-time analysis to mine the information across the posture variations. Using this information, we recover the human body, regardless of the effect of clothes, and measure the human body parameters accurately. Experimental results show that our system can perform more accurate parameter estimation on the human body than state-of-the-art methods. PMID:24064597

  8. An accurate and efficient algorithm for Peptide and ptm identification by tandem mass spectrometry.

    PubMed

    Ning, Kang; Ng, Hoong Kee; Leong, Hon Wai

    2007-01-01

    Peptide identification by tandem mass spectrometry (MS/MS) is one of the most important problems in proteomics. Recent advances in high throughput MS/MS experiments result in huge amount of spectra. Unfortunately, identification of these spectra is relatively slow, and the accuracies of current algorithms are not high with the presence of noises and post-translational modifications (PTMs). In this paper, we strive to achieve high accuracy and efficiency for peptide identification problem, with special concern on identification of peptides with PTMs. This paper expands our previous work on PepSOM with the introduction of two accurate modified scoring functions: Slambda for peptide identification and Slambda* for identification of peptides with PTMs. Experiments showed that our algorithm is both fast and accurate for peptide identification. Experiments on spectra with simulated and real PTMs confirmed that our algorithm is accurate for identifying PTMs. PMID:18546510

  9. Infrared reflectance spectra: Effects of particle size, provenance and preparation

    SciTech Connect

    Su, Yin-Fong; Myers, Tanya L.; Brauer, Carolyn S.; Blake, Thomas A.; Forland, Brenda M.; Szecsody, James E.; Johnson, Timothy J.

    2014-09-22

    We have recently developed methods for making more accurate infrared total and diffuse directional - hemispherical reflectance measurements using an integrating sphere. We have found that reflectance spectra of solids, especially powders, are influenced by a number of factors including the sample preparation method, the particle size and morphology, as well as the sample origin. On a quantitative basis we have investigated some of these parameters and the effects they have on reflectance spectra, particularly in the longwave infrared. In the IR the spectral features may be observed as either maxima or minima: In general, upward-going peaks in the reflectance spectrum result from strong surface scattering, i.e. rays that are reflected from the surface without bulk penetration, whereas downward-going peaks are due to either absorption or volume scattering, i.e. rays that have penetrated or refracted into the sample interior and are not reflected. The light signals reflected from solids usually encompass all such effects, but with strong dependencies on particle size and preparation. This paper measures the reflectance spectra in the 1.3 – 16 micron range for various bulk materials that have a combination of strong and weak absorption bands in order to observe the effects on the spectral features: Bulk materials were ground with a mortar and pestle and sieved to separate the samples into various size fractions between 5 and 500 microns. The median particle size is demonstrated to have large effects on the reflectance spectra. For certain minerals we also observe significant spectral change depending on the geologic origin of the sample. All three such effects (particle size, preparation and provenance) result in substantial change in the reflectance spectra for solid materials; successful identification algorithms will require sufficient flexibility to account for these parameters.

  10. Current awareness

    PubMed

    Green; Feher; Catalan

    2000-07-01

    In order to keep subscribers up-to-date with the latest developments in their field, John Wiley & Sons are providing a current awareness service in each issue of the journal. The bibliography contains newly published material in the field of diabetes/metabolism. Each bibliography is divided into 17 sections: 1 Books, Reviews & Symposia; 2 General; 3 Genetics; 4 Epidemiology; 5 Immunology; 6 Prediction; 7 Prevention; 8 Intervention: a&rpar General; b&rpar Pharmacology; 9 Pathology: a&rpar General; b&rpar Cardiovascular; c&rpar Neurological; d&rpar Renal; 10 Endocrinology & Metabolism; 11 Nutrition; 12 Animal Studies; 13 Techniques. Within each section, articles are listed in alphabetical order with respect to author (8 Weeks journals - Search completed at 19th Apr. 2000) PMID:10934459

  11. Virtual reflections in electronic acoustic architecture

    NASA Astrophysics Data System (ADS)

    van Munster, Bjorn

    2005-09-01

    In the era of the ancient Greeks and Byzantines, the first attempts for increasing reverberation time are noted. In the 1950s, the Ambiophonic system accomplished this by means of an electronic device, for the first time. The early systems only increased the reverberation time by delaying the picked-up reverberation. With the introduction of multichannel feedback-based systems, the reverberation level also could be increased. Later, it was understood that it was important to also fill in the missing reflections, address reflection density, frequency dependence, etc. This resulted in the development of the SIAP concept. Current DSP technology led to the development of a processor whereby density, length, level, and the frequency content can be controlled for different areas in the same room or different rooms, leading to the concept of the acoustic server. electronic acoustic architecture has become the current state-of-the-art approach for solving acoustic deficiencies in, among others, rehearsal rooms, theaters, churches, and multipurpose venues. Incorporation of complementary passive acoustic solutions provides an optimum solution for all room problems. This paper discusses the utilization of virtual reflections in the new approach of electronic acoustic architecture for different environments. Measurements performed in the Sejong Performing Arts Centre, Seoul, South Korea, show the power of this approach.

  12. Reflections on Electric Probes

    NASA Astrophysics Data System (ADS)

    Braithwaite, Nicholas

    2007-10-01

    One of the more immediate temptations for an experimental plasma physicist is to insert some kind of refractory, conducting material into a plasma, as a simple means of probing its charge composition. Irvine Langmuir tried it in the 1920s and was one of the first to develop an electrical probe method in his early work on electrical discharge plasmas. There are now numerous variations on the theme including planar, cylindrical and spherical geometry with single, double and triple probes. There are also probes that resonate, propagate and reciprocate. Some probes are electrostatic and others are electromagnetic; some are effectively wireless; most absorb but some emit. All types can be used in steady and transient plasmas, while special schemes have been devised for RF plasmas, using passive and active compensation. Magnetised plasmas pose further challenges. Each configuration is accompanied by assumptions that constrain both their applicability and the analytical methods that translate the measured currents and voltages variously into charge densities, space potentials, particle fluxes, energy distributions and measures of collisionality. This talk will take a broad look at the options and opportunities for electric probes, principally in the environment of non-equilibrium plasma.

  13. CT-Analyst: fast and accurate CBR emergency assessment

    NASA Astrophysics Data System (ADS)

    Boris, Jay; Fulton, Jack E., Jr.; Obenschain, Keith; Patnaik, Gopal; Young, Theodore, Jr.

    2004-08-01

    An urban-oriented emergency assessment system for airborne Chemical, Biological, and Radiological (CBR) threats, called CT-Analyst and based on new principles, gives greater accuracy and much greater speed than possible with current alternatives. This paper explains how this has been done. The increased accuracy derives from detailed, three-dimensional CFD computations including, solar heating, buoyancy, complete building geometry specification, trees, wind fluctuations, and particle and droplet distributions (as appropriate). This paper shows how a very finite number of such computations for a given area can be extended to all wind directions and speeds, and all likely sources and source locations using a new data structure called Dispersion Nomographs. Finally, we demonstrate a portable, entirely graphical software tool called CT-Analyst that embodies this entirely new, high-resolution technology and runs effectively on small personal computers. Real-time users don't have to wait for results because accurate answers are available with near zero-latency (that is 10 - 20 scenarios per second). Entire sequences of cases (e.g. a continuously changing source location or wind direction) can be computed and displayed as continuous-action movies. Since the underlying database has been precomputed, the door is wide open for important new real-time, zero-latency functions such as sensor data fusion, backtracking to an unknown source location, and even evacuation route planning. Extensions of the technology to sensor location optimization, buildings, tunnels, and integration with other advanced technologies, e.g. micrometeorology or detailed wind field measurements, will be discussed briefly here.

  14. Can Reflective Practice Be Taught?

    ERIC Educational Resources Information Center

    Edwards, Gail; Thomas, Gary

    2010-01-01

    Almost ubiquitous in discourses about the development of teachers, reflective practice describes the process that occurs when persons are apprenticed to any meaningful activity. But reflective practice is a descriptive term for that process: it does not imply that the process is itself open to dissection and instruction. We contend that mistaken…

  15. Reflections on Becoming a Researcher

    ERIC Educational Resources Information Center

    Frankel, Katherine K.; Pearson, P. David

    2013-01-01

    In this joint reflection two of the contributors to this issue of the "Journal of Education" consider the processes and practices that led to the publication of their respective pieces. Since one of the authors, Katherine Frankel, was a doctoral advisee of the other, David Pearson, they also reflect on the mentoring practices they shared…

  16. Flexible Bistable Cholesteric Reflective Displays

    NASA Astrophysics Data System (ADS)

    Yang, Deng-Ke

    2006-03-01

    Cholesteric liquid crystals (ChLCs) exhibit two stable states at zero field condition-the reflecting planar state and the nonreflecting focal conic state. ChLCs are an excellent candidate for inexpensive and rugged electronic books and papers. This paper will review the display cell structure,materials and drive schemes for flexible bistable cholesteric (Ch) reflective displays.

  17. Incorporating reflection into veterinary practice.

    PubMed

    2016-05-21

    New graduates are encouraged to reflect on their progress during their Professional Development Phase, but what does reflection really mean, and how can veterinary professionals use it to better their day-to-day practice? This was a topic discussed during an afternoon of sessions at the recent BSAVA congress in Birmingham. Georgina Mills reports. PMID:27199044

  18. Reflections on Justice in Schooling

    ERIC Educational Resources Information Center

    First, Patricia F.

    2012-01-01

    This article is a reflection on the concept of justice as practiced in the public schools in the United States. Examples of justice denied or misconstrued are included. Cases, stories, and concepts invite educational leaders to reflect anew on delivering justice in education to all children. Underlying the article is the belief that understanding…

  19. Children's Literature-Some Reflections.

    ERIC Educational Resources Information Center

    Root, Shelton L., Jr.

    Ten reflections may be made regarding children's literature and its teaching. The reflections are as follows: (1) Teachers can make a profound difference in the lives of students and should attempt to do so. (2) Teachers of children's literature are a badly fragmented lot and need a common meeting ground where they can share their thinking. (3)…

  20. Making Connections to Teach Reflection

    ERIC Educational Resources Information Center

    Correia, Manuel G.; Bleicher, Robert E.

    2008-01-01

    Approaching reflection from the perspective of a teachable skill set implies that research may inform how to help students reflect. Employing a framework of making connections often used in reading comprehension, this study aimed to characterize how making connections between the service-learning experience (SLE) and prior experiences in similar…

  1. Why Reflection in Teacher Education?

    ERIC Educational Resources Information Center

    LaBoskey, Vicki Kubler

    1993-01-01

    Focuses on preservice teacher education by considering teacher reflectivity as an end rather than a means. The article provides a rationale for reflective teacher education in arguing the need to have teachers who are thoughtful, passionate, and principled educational decision makers. (GLR)

  2. Troubling Muddy Waters: Problematizing Reflective Practice in Global Medical Education.

    PubMed

    Naidu, Thirusha; Kumagai, Arno K

    2016-03-01

    The idea of exporting the concept of reflective practice for a global medical education audience is growing. However, the uncritical export and adoption of Western concepts of reflection may be inappropriate in non-Western societies. The emphasis in Western medical education on the use of reflection for a specific end--that is, the improvement of individual clinical practice--tends to ignore the range of reflective practice, concentrating on reflection alone while overlooking critical reflection and reflexivity. This Perspective places the concept of reflective practice under a critical lens to explore a broader view for its application in medical education outside the West. The authors suggest that ideas about reflection in medicine and medical education may not be as easily transferable from Western to non-Western contexts as concepts from biomedical science are. The authors pose the question, When "exporting" Western medical education strategies and principles, how often do Western-trained educators authentically open up to the possibility that there are alternative ways of seeing and knowing that may be valuable in educating Western physicians? One answer lies in the assertion that educators should aspire to turn exportation of educational theory into a truly bidirectional, collaborative exchange in which culturally conscious views of reflective practice contribute to humanistic, equitable patient care. This discussion engages in troubling the already-muddy waters of reflective practice by exploring the global applicability of reflective practice as it is currently applied in medical education. The globalization of medical education demands critical reflection on reflection itself. PMID:26630601

  3. The NCTM Research Presession: A Brief History and Reflection

    ERIC Educational Resources Information Center

    Journal for Research in Mathematics Education, 2014

    2014-01-01

    The NCTM Research Committee invited Richard Lesh, instrumental in the founding of the NCTM Research Presession, to join the members of the current Research Committee in reflecting on its formation, the hopes he and others had in mind when they started it, and the current state and future of research in the field.

  4. The Reflecting Team: A Training Method for Family Counselors

    ERIC Educational Resources Information Center

    Chang, Jeff

    2010-01-01

    The reflecting team (RT) is an innovative method used in the training and supervision of family counselors. In this article, I trace the history, development, and current uses of RTs and review current findings on RTs. In my opinion, many users of RTs have diverged from their original theoretical principles and have adopted RTs mainly as a…

  5. In Their Own Words: Teachers' Reflections on Adaptability

    ERIC Educational Resources Information Center

    Vaughn, Margaret; Parsons, Seth A.; Burrowbridge, Sarah Cohen; Weesner, Janice; Taylor, Laurel

    2016-01-01

    Current research explores adaptability by gathering teachers' reflections on their adaptations. However, the field knows little of what the term "adaptability" means to teachers who currently teach in today's educational context. In this article, adaptability is discussed from the perspectives of 3 practicing classroom educators,…

  6. [Concept analysis of reflective thinking].

    PubMed

    Van Vuuren, M; Botes, A

    1999-09-01

    The nursing practice is described as a scientific practice, but also as a practice where caring is important. The purpose of nursing education is to provide competent nursing practitioners. This implies that future practitioners must have both critical analytical thinking abilities, as well as empathy and moral values. Reflective thinking could probably accommodate these thinking skills. It seems that the facilitation of reflective thinking skills is essential in nursing education. The research question that is relevant in this context is: "What is reflective thinking?" The purpose of this article is to report on the concept analysis of reflective thinking and in particular on the connotative meaning (critical attributes) thereof. The method used to perform the concept analysis is based on the original method of Wilson (1987) as described by Walker & Avant (1995). As part of the concept analysis the connotations (critical attributes) are identified, reduced and organized into three categories, namely pre-requisites, processes and outcomes. A model case is described which confirms the essential critical attributes of reflective thinking. Finally a theoretical definition of reflective thinking is derived and reads as follows: Reflective thinking is a cyclic, hierarchical and interactive construction process. It is initiated, extended and continued because of personal cognitive-affective interaction (individual dimension) as well as interaction with the social environment (social dimension). to realize reflective thinking, a level of internalization on the cognitive and affective domain is required. The result of reflective thinking is a integrated framework of knowledge (meaningful learning) and a internalized value system providing a new perspective on and better understanding of a problem. Reflective thinking further leads to more effective decision making- and problem solving skills. PMID:11040626

  7. Reflectance spectroscopy of organic compounds: 1. Alkanes

    USGS Publications Warehouse

    Clark, R.N.; Curchin, J.M.; Hoefen, T.M.; Swayze, G.A.

    2009-01-01

    Reflectance spectra of the organic compounds comprising the alkane series are presented from the ultraviolet to midinfrared, 0.35 to 15.5 /??m. Alkanes are hydrocarbon molecules containing only single carbon-carbon bonds, and are found naturally on the Earth and in the atmospheres of the giant planets and Saturn's moon, Titan. This paper presents the spectral properties of the alkanes as the first in a series of papers to build a spectral database of organic compounds for use in remote sensing studies. Applications range from mapping the environment on the Earth, to the search for organic molecules and life in the solar system and throughout the. universe. We show that the spectral reflectance properties of organic compounds are rich, with major diagnostic spectral features throughout the spectral range studied. Little to no spectral change was observed as a function of temperature and only small shifts and changes in the width of absorption bands were observed between liquids and solids, making remote detection of spectral properties throughout the solar system simpler. Some high molecular weight organic compounds contain single-bonded carbon chains and have spectra similar to alkanes even ' when they fall into other families. Small spectral differences are often present allowing discrimination among some compounds, further illustrating the need to catalog spectral properties for accurate remote sensing identification with spectroscopy.

  8. Accurate calculation of diffraction-limited encircled and ensquared energy.

    PubMed

    Andersen, Torben B

    2015-09-01

    Mathematical properties of the encircled and ensquared energy functions for the diffraction-limited point-spread function (PSF) are presented. These include power series and a set of linear differential equations that facilitate the accurate calculation of these functions. Asymptotic expressions are derived that provide very accurate estimates for the relative amount of energy in the diffraction PSF that fall outside a square or rectangular large detector. Tables with accurate values of the encircled and ensquared energy functions are also presented. PMID:26368873

  9. Novel electromagnetic surface integral equations for highly accurate computations of dielectric bodies with arbitrarily low contrasts

    SciTech Connect

    Erguel, Ozguer; Guerel, Levent

    2008-12-01

    We present a novel stabilization procedure for accurate surface formulations of electromagnetic scattering problems involving three-dimensional dielectric objects with arbitrarily low contrasts. Conventional surface integral equations provide inaccurate results for the scattered fields when the contrast of the object is low, i.e., when the electromagnetic material parameters of the scatterer and the host medium are close to each other. We propose a stabilization procedure involving the extraction of nonradiating currents and rearrangement of the right-hand side of the equations using fictitious incident fields. Then, only the radiating currents are solved to calculate the scattered fields accurately. This technique can easily be applied to the existing implementations of conventional formulations, it requires negligible extra computational cost, and it is also appropriate for the solution of large problems with the multilevel fast multipole algorithm. We show that the stabilization leads to robust formulations that are valid even for the solutions of extremely low-contrast objects.

  10. Inference of dense spectral reflectance images from sparse reflectance measurement using non-linear regression modeling

    NASA Astrophysics Data System (ADS)

    Deglint, Jason; Kazemzadeh, Farnoud; Wong, Alexander; Clausi, David A.

    2015-09-01

    One method to acquire multispectral images is to sequentially capture a series of images where each image contains information from a different bandwidth of light. Another method is to use a series of beamsplitters and dichroic filters to guide different bandwidths of light onto different cameras. However, these methods are very time consuming and expensive and perform poorly in dynamic scenes or when observing transient phenomena. An alternative strategy to capturing multispectral data is to infer this data using sparse spectral reflectance measurements captured using an imaging device with overlapping bandpass filters, such as a consumer digital camera using a Bayer filter pattern. Currently the only method of inferring dense reflectance spectra is the Wiener adaptive filter, which makes Gaussian assumptions about the data. However, these assumptions may not always hold true for all data. We propose a new technique to infer dense reflectance spectra from sparse spectral measurements through the use of a non-linear regression model. The non-linear regression model used in this technique is the random forest model, which is an ensemble of decision trees and trained via the spectral characterization of the optical imaging system and spectral data pair generation. This model is then evaluated by spectrally characterizing different patches on the Macbeth color chart, as well as by reconstructing inferred multispectral images. Results show that the proposed technique can produce inferred dense reflectance spectra that correlate well with the true dense reflectance spectra, which illustrates the merits of the technique.

  11. Plant canopy specular reflectance model

    NASA Technical Reports Server (NTRS)

    Vanderbilt, V. C.; Grant, L.

    1985-01-01

    A model is derived for the amount of light specularly reflected and polarized by a plant canopy. The model is based on the morphological and phenological characteristics of the canopy and upon the Fresnel equations of optics. The theory demonstrates that the specular reflectance of the plant canopy is a function of the angle of incidence and potentially contains information to help discriminate between species. The theory relates the specular reflectance to botanical condition of the canopy - to factors such as development stage, plant vigor, and leaf area index (LAI).

  12. Accurate Alignment of Plasma Channels Based on Laser Centroid Oscillations

    SciTech Connect

    Gonsalves, Anthony; Nakamura, Kei; Lin, Chen; Osterhoff, Jens; Shiraishi, Satomi; Schroeder, Carl; Geddes, Cameron; Toth, Csaba; Esarey, Eric; Leemans, Wim

    2011-03-23

    A technique has been developed to accurately align a laser beam through a plasma channel by minimizing the shift in laser centroid and angle at the channel outptut. If only the shift in centroid or angle is measured, then accurate alignment is provided by minimizing laser centroid motion at the channel exit as the channel properties are scanned. The improvement in alignment accuracy provided by this technique is important for minimizing electron beam pointing errors in laser plasma accelerators.

  13. Accurate wavelength calibration method for flat-field grating spectrometers.

    PubMed

    Du, Xuewei; Li, Chaoyang; Xu, Zhe; Wang, Qiuping

    2011-09-01

    A portable spectrometer prototype is built to study wavelength calibration for flat-field grating spectrometers. An accurate calibration method called parameter fitting is presented. Both optical and structural parameters of the spectrometer are included in the wavelength calibration model, which accurately describes the relationship between wavelength and pixel position. Along with higher calibration accuracy, the proposed calibration method can provide information about errors in the installation of the optical components, which will be helpful for spectrometer alignment. PMID:21929865

  14. IRIS: Towards an Accurate and Fast Stage Weight Prediction Method

    NASA Astrophysics Data System (ADS)

    Taponier, V.; Balu, A.

    2002-01-01

    , validated on several technical and econometrical cases, has been used for this purpose. A database of several conventional stages, operated with either solid or liquid propellants, has been made up, in conjunction with an evolutionary set of geometrical, physical and functional parameters likely to contribute to the description of the mass fraction and presumably known at the early steps of the preliminary design. After several iterations aiming at selecting the most influential parameters, polynomial expressions of the mass fraction have been made up, associated to a confidence level. The outcome highlights the real possibility of a parametric formulation of the mass fraction for conventional stages on the basis of a limited number of descriptive parameters and with a high degree of accuracy, lower than 10%. The formulas have been later on tested on existing or preliminary stages not included in the initial database, for validation purposes. Their mass faction is assessed with a comparable accuracy. The polynomial generation method in use allows also for a search of the influence of each parameter. The devised method, suitable for the preliminary design phase, represents, compared to the classical empirical approach, a significant way of improvement of the mass fraction prediction. It enables a rapid dissemination of more accurate and consistent weight data estimates to support system studies. It makes also possible the upstream processing of the preliminary design tasks through a global system approach. This method, currently in the experimental phase, is already in use as a complementary means at the technical underdirectorate of CNES-DLA. * IRIS :Instrument de Recherche des Indices Structuraux

  15. Reflectance and Fluorescence Spectral Recovery via Actively Lit RGB Images.

    PubMed

    Fu, Ying; Lam, Antony; Sato, Imari; Okabe, Takahiro; Sato, Yoichi

    2016-07-01

    In recent years, fluorescence analysis of scenes has received attention in computer vision. Fluorescence can provide additional information about scenes, and has been used in applications such as camera spectral sensitivity estimation, 3D reconstruction, and color relighting. In particular, hyperspectral images of reflective-fluorescent scenes provide a rich amount of data. However, due to the complex nature of fluorescence, hyperspectral imaging methods rely on specialized equipment such as hyperspectral cameras and specialized illuminants. In this paper, we propose a more practical approach to hyperspectral imaging of reflective-fluorescent scenes using only a conventional RGB camera and varied colored illuminants. The key idea of our approach is to exploit a unique property of fluorescence: the chromaticity of fluorescent emissions are invariant under different illuminants. This allows us to robustly estimate spectral reflectance and fluorescent emission chromaticity. We then show that given the spectral reflectance and fluorescent chromaticity, the fluorescence absorption and emission spectra can also be estimated. We demonstrate in results that all scene spectra can be accurately estimated from RGB images. Finally, we show that our method can be used to accurately relight scenes under novel lighting. PMID:27295456

  16. Towards the development of a reflective radiographer: challenges and constraints

    PubMed Central

    Baird, MA

    2008-01-01

    Currently there is overwhelming support from the health professions for universities to devise curricular approaches that lead to the development of undergraduate reflective skills, and over time, reflective practice. However, in the case of radiography, irrespective of the degree to which radiographers might engage in reflective practice they constantly struggle to shed the perception they are little more than technical operatives. The four-year Bachelor of Radiography and Medical Imaging was introduced by Monash University in 1998 with an overt commitment to the development of a reflective radiographer. Findings from student and supervisor surveys generally support the program and its aims. However, as the findings and student feedback will attest, many challenges and constraints continue to face educators who seek to situate their curriculum within the reflective practice paradigm. PMID:21614320

  17. Remineralization of enamel caries can decrease optical reflectivity.

    PubMed

    Jones, R S; Fried, D

    2006-09-01

    The remineralization of enamel caries can lead to distinct optical changes within a lesion. We hypothesized that the restoration of mineral volume would result in a measurable decrease in the depth-resolved reflectivity of polarized light from the lesion. To test this hypothesis, we measured optical changes in artificial caries undergoing remineralization as a function of depth, using Polarization-sensitive Optical Coherence Tomography (PS-OCT). Lesions were imaged non-destructively before and after exposure to a remineralization regimen. After imaging, microradiographs of histological thin sections indicated that the significant reflectivity reduction measured by PS-OCT accurately represented the increase in mineral content within a larger repaired surface zone. Mineral volume changes arising from remineralization can be measured on the basis of the optical reflectivity of the lesion. PMID:16931861

  18. Accurate boundary conditions for exterior problems in gas dynamics

    NASA Technical Reports Server (NTRS)

    Hagstrom, Thomas; Hariharan, S. I.

    1988-01-01

    The numerical solution of exterior problems is typically accomplished by introducing an artificial, far field boundary and solving the equations on a truncated domain. For hyperbolic systems, boundary conditions at this boundary are often derived by imposing a principle of no reflection. However, waves with spherical symmetry in gas dynamics satisfy equations where incoming and outgoing Riemann variables are coupled. This suggests that natural reflections may be important. A reflecting boundary condition is proposed based on an asymptotic solution of the far field equations. Nonlinear energy estimates are obtained for the truncated problem and numerical experiments presented to validate the theory.

  19. Accurate boundary conditions for exterior problems in gas dynamics

    NASA Technical Reports Server (NTRS)

    Hagstrom, Thomas; Hariharan, S. I.

    1988-01-01

    The numerical solution of exterior problems is typically accomplished by introducing an artificial, far-field boundary and solving the equations on a truncated domain. For hyperbolic systems, boundary conditions at this boundary are often derived by imposing a principle of no reflection. However, waves with spherical symmetry in gas dynamics satisfy equations where incoming and outgoing Riemann variables are coupled. This suggests that natural reflections may be important. A reflecting boundary condition is proposed based on an asymptotic solution of the far-field equations. Nonlinear energy estimates are obtained for the truncated problem and numerical experiments presented to validate the theory.

  20. Exploring Pre-Service Classroom Teachers' Reflections on Teaching Physical Education

    ERIC Educational Resources Information Center

    Tsangaridou, Niki; Polemitou, Irene

    2015-01-01

    The aim of the current study was to provide descriptions of the nature of pre-service primary teachers' reflection during their student teaching experience. The principal research question that guided the investigation was "what do these pre-service classroom teachers reflect on during their teaching and how is this reflection related to…

  1. Student Reflective Writing: Cognition and Affect before, during, and after Study Abroad

    ERIC Educational Resources Information Center

    Savicki, Victor; Price, Michele V.

    2015-01-01

    Reflective thinking is an important feature of study-abroad learning, yet research on reflection in this context is sparse. The current study examined student reflection on 3 content areas (Academic Expectations, Cultural Expectations, and Psychological Issues) at 3 times (before, during, and after study abroad). A content analysis approach with…

  2. The Constellation-X Reflection Grating Spectrometer

    NASA Technical Reports Server (NTRS)

    Allen, Jean C.

    2006-01-01

    The Reflection Grating Spectrometer on the Constellation-X mission will provide high sensitivity, high-resolution spectra in the soft x-ray band. The RGS performance requirements are specified as a resolving power of greater than 300 and an effective area of greater than 1000 sq cm across most of the 0.25 to 2.0 keV band. These requirements are driven by the science goals of the mission. We will describe the performance requirements and goals, the reference design of the spectrometer, and examples of science cases where we expect data from the RGS to significantly advance our current understanding of the universe.

  3. Andreev reflection in graphene nanoribbons

    NASA Astrophysics Data System (ADS)

    Rainis, Diego; Taddei, Fabio; Dolcini, Fabrizio; Polini, Marco; Fazio, Rosario

    2009-03-01

    We study Andreev reflection in graphene nanoribbon/superconductor hybrid junctions. By using a tight-binding approach and the scattering formalism we show that finite-size effects lead to notable differences with respect to the bulk-graphene case. At subgap voltages, conservation of pseudoparity, a quantum number characterizing the ribbon states, yields either a suppression of Andreev reflection when the ribbon has an even number of sites in the transverse direction or perfect Andreev reflection when the ribbon has an odd number of sites. In the former case the suppression of Andreev reflection induces an insulating behavior even when the junction is biased; electron conduction can however be restored by applying a gate voltage. Finally, we check that these findings remain valid also in the case of nonideal nanoribbons in which the number of transverse sites varies along the transport direction.

  4. Reflections after the Diane affair.

    PubMed

    Kant, A; van Puijenbroek, E; van Hunsel, F

    2014-09-01

    The Pharmacovigilance Centre Lareb received 621 reports of possible adverse drugs reactions on Diane-35® . Of all reports, 388 were received after media attention. Of the 309 reports of thromboembolic adverse drugs reactions, 18 cases were fatal. In 31 cases the thromboembolic adverse drugs reaction was initially not recognized as such. The analysis and the turmoil of the 'Diane affair' gave rise to the following reflections: Reflection 1. Continuous awareness and attention of risk of medicines is needed, also for known risks, for timely recognition of adverse drugs reactions. Reflection 2. Reporting side effects should be part of the professional attitude. Reports play a pivotal role in the detection of new adverse drugs reactions and the conditions under which known adverse drugs reactions occur. Reflection 3. Improvement of adequate use of drugs. Pharmacovigilance not only has the aim to improve knowledge on risk of medicines, but also the aim of getting this knowledge into Health Care practice. PMID:24909698

  5. Reflection of cylindrical surface waves.

    PubMed

    Gordon, Reuven

    2009-10-12

    The reflection of the radially polarized surface wave on a metal wire at an abrupt end is derived. This theory allows for straightforward calculation of the reflection coefficient, including the phase and the amplitude, which will prove useful to the many applications in nanoplasmonics and terahertz spectroscopy. The theory shows excellent quantitative agreement with past comprehensive numerical simulations for small wires and for predicting the minima in reflection for larger wires. Using this theory, the wavelength dependent reflection is calculated for gold rods of diameter 10 nm, 26 nm and 85 nm, from which the Fabry-Perot resonance wavelengths are found. The Fabry-Perot resonances show good agreement with experimentally measured surface plasmon resonances in nanorods. This demonstrates the predictive ability of the theory for applications involving widely-used nanorods, optical antennas and plasmonic resonators. PMID:20372593

  6. Teacher Education and Teacher Reflectivity.

    ERIC Educational Resources Information Center

    Bullough Jr., Robert V.

    1989-01-01

    The efforts of a small group of teacher educators to develop a program emphasizing reflectivity is described. Grounding program development in a conceptual framework is emphasized. Lessons learned about the program development process are shared. (IAH)

  7. The Advantages of an Attenuated Total Internal Reflection Infrared Microspectroscopic Imaging Approach for Kidney Biopsy Analysis

    PubMed Central

    Gulley-Stahl, Heather J.; Bledsoe, Sharon B.; Evan, Andrew P.; Sommer, André J.

    2011-01-01

    The benefits of an ATR-FTIR imaging approach for kidney biopsy analysis are described. Biopsy sections collected from kidney stone formers are analyzed at the initial stages of stone development to provide insights into stone growth and formation. The majority of tissue analysis currently conducted with IR microspectroscopy is performed with a transflection method. The research presented in this manuscript demonstrates that ATR overcomes many of the disadvantages of transflection or transmission measurements for tissue analysis including an elimination of spectral artifacts. When kidney biopsies with small mineral inclusions are analyzed with a transflection approach, specular reflection, and the Christiansen effect (anomalous dispersion) can occur leading to spectral artifacts. Another effect specific to the analysis of mineral inclusions present in kidney biopsies is known as the reststrahlen effect where the inclusions become strong reflectors near an absorption band. ATR eliminates these effects by immersing the sample in a high index medium. Additionally, the focused beam size for ATR is decreased by a factor of four when a germanium internal reflection element is used, allowing the acquisition of spectra from small mineral inclusions several micrometers in diameter. If quantitative analysis of small mineral inclusions is ultimately desired, ATR provides the photometrically accurate spectra necessary for quantification. PMID:20132593

  8. Reflections on wisdom and self.

    PubMed

    Samuel, Sophie

    2012-12-01

    The end of the year is often a time of reflection. For most of us, 2012 will have brought events that were planned, perhaps for years, as well as others that were full of serendipity or unexpected misfortune. We are invariably older than we were in January. We approach December with our own rituals: summer holidays, Hanukkah, Christmas or New Year's Eve. We may reflect on our joys and disappointments, or our actions and lessons learnt. PMID:23342382

  9. Reflective terahertz (THz) imaging: system calibration using hydration phantoms

    NASA Astrophysics Data System (ADS)

    Bajwa, Neha; Garritano, James; Lee, Yoon Kyung; Tewari, Priyamvada; Sung, Shijun; Maccabi, Ashkan; Nowroozi, Bryan; Babakhanian, Meghedi; Sanghvi, Sajan; Singh, Rahul; Grundfest, Warren; Taylor, Zachary

    2013-02-01

    Terahertz (THz) hydration sensing continues to gain traction in the medical imaging community due to its unparalleled sensitivity to tissue water content. Rapid and accurate detection of fluid shifts following induction of thermal skin burns as well as remote corneal hydration sensing have been previously demonstrated in vivo using reflective, pulsed THz imaging. The hydration contrast sensing capabilities of this technology were recently confirmed in a parallel 7 Tesla Magnetic Resonance (MR) imaging study, in which burn areas are associated with increases in local mobile water content. Successful clinical translation of THz sensing, however, still requires quantitative assessments of system performance measurements, specifically hydration concentration sensitivity, with tissue substitutes. This research aims to calibrate the sensitivity of a novel, reflective THz system to tissue water content through the use of hydration phantoms for quantitative comparisons of THz hydration imagery.Gelatin phantoms were identified as an appropriate tissue-mimicking model for reflective THz applications, and gel composition, comprising mixtures of water and protein, was varied between 83% to 95% hydration, a physiologically relevant range. A comparison of four series of gelatin phantom studies demonstrated a positive linear relationship between THz reflectivity and water concentration, with statistically significant hydration sensitivities (p < .01) ranging between 0.0209 - 0.038% (reflectivity: %hydration). The THz-phantom interaction is simulated with a three-layer model using the Transfer Matrix Method with agreement in hydration trends. Having demonstrated the ability to accurately and noninvasively measure water content in tissue equivalent targets with high sensitivity, reflective THz imaging is explored as a potential tool for early detection and intervention of corneal pathologies.

  10. Experiments on Guderley Mach reflection

    NASA Astrophysics Data System (ADS)

    Skews, Beric William; Li, Gavin; Paton, Randall

    2009-06-01

    Experiments have been conducted in a large shock tube to examine the four-wave shock reflection pattern, now known as Guderley reflection (GR). The fourth wave, an expansion, is clearly identified, as is the supersonic patch behind the reflected wave. A shocklet terminating the supersonic patch behind the reflected wave is identified, which forms a second triple point further down the Mach stem. Evidence is presented showing the presence of more than one expansion wave and more than one shocklet, thus indicating the existence of more than one supersonic patch. In order to distinguish between cases with a single patch without the shocklet as originally proposed by Guderley and found in some computations, and the indications of a multi-patch geometry found here, and also in other computations, this latter case is designated Guderley Mach reflection (GMR). Multi-exposure images of the shock propagation superimposed on a single image frame enable estimates to be made of the strength of the major waves, and it is shown that the reflected wave is very weak.

  11. Reflective Practice in Physical Education and Physical Education Teacher Education: A Review of the Literature since 1995

    ERIC Educational Resources Information Center

    Standal, Oyvind F.; Moe, Vegard F.

    2013-01-01

    Reflection and reflective practice are key concepts in the educational literature as well as in research on physical education (PE) and physical education teacher education (PETE). The purpose of this article is to review the current empirical knowledge base for reflection and reflective practice in PE and PETE from 1995 to 2011. The review…

  12. Rethinking reflective education: What would Dewey have done?

    PubMed

    Rolfe, Gary

    2014-08-01

    Reflective practice has largely failed to live up to its promise of offering a radical critique of technical rationality and of ushering in a new philosophy of nursing practice and education. I argue in this paper that the failure lies not with the idea of reflective practice itself, but with the way in which it has been misunderstood, misinterpreted and misapplied by managers, theorists, educators and practitioners over the past two decades. I suggest that if reflective practice is to offer a credible alternative to the current technical-rational evidence-based approach to nursing, then it needs to rediscover its radical origins in the work of John Dewey and Donald Schön. In particular, nurses need to look beyond their current fixation with reflection-on-action and engage fully with Schön's notion of the reflective practitioner who reflects in action through on-the-spot experimentation and hypothesis testing. Finally, the implications of this radical approach to reflective practice are developed in relation to the practice of nursing, education and scholarship, where they are applied to the challenge of resolving what Rittel and Webber refer to as 'wicked problems'. PMID:24713127

  13. Recent developments and results of new ultraviolet reflective mirror coatings

    NASA Astrophysics Data System (ADS)

    Moore, Christopher S.; Hennessy, John; Jewell, April D.; Nikzad, Shouleh; France, Kevin

    2014-07-01

    Astronomical observations in the Lyman-ultraviolet (91 - 122 nm) are limited in part by the performance of reflective coatings. Currently, the best reflective mirror options for the UV wavelength range of 90 -122 nm are LiF+Al (R ~ 60% from 102 - 200 nm) and SiC (R ~ 30 % from 90 - 200 nm). Higher reflectivity coatings in the 90 - 122 nm range will improve sensitivity and allow for more complex instrumentation. We are working to develop, laboratory test and eventually space test new reflective UV coatings (R > 70% from 90 - 115 nm) that also preserve high-reflectivity performance (R > 80% from 115 - 800 nm) throughout the longer-wavelength vacuum ultraviolet and visible spectral bands. We present a progress report on our work with new protective thin film deposition techniques of metal fluorides (MgF2 and AlF3) on high intrinsic broadband reflective metal (aluminum) surfaces. We present first test results from both traditional and atomic layer deposition processes. In this paper, we discuss the current status of the deposition process, coating substrates, reflectivity measurements for optical through far-ultraviolet wavelengths as well as environmental storage sensitivities.

  14. Hyperspectral Fluorescence and Reflectance Imaging Instrument

    NASA Technical Reports Server (NTRS)

    Ryan, Robert E.; O'Neal, S. Duane; Lanoue, Mark; Russell, Jeffrey

    2008-01-01

    The system is a single hyperspectral imaging instrument that has the unique capability to acquire both fluorescence and reflectance high-spatial-resolution data that is inherently spatially and spectrally registered. Potential uses of this instrument include plant stress monitoring, counterfeit document detection, biomedical imaging, forensic imaging, and general materials identification. Until now, reflectance and fluorescence spectral imaging have been performed by separate instruments. Neither a reflectance spectral image nor a fluorescence spectral image alone yields as much information about a target surface as does a combination of the two modalities. Before this system was developed, to benefit from this combination, analysts needed to perform time-consuming post-processing efforts to co-register the reflective and fluorescence information. With this instrument, the inherent spatial and spectral registration of the reflectance and fluorescence images minimizes the need for this post-processing step. The main challenge for this technology is to detect the fluorescence signal in the presence of a much stronger reflectance signal. To meet this challenge, the instrument modulates artificial light sources from ultraviolet through the visible to the near-infrared part of the spectrum; in this way, both the reflective and fluorescence signals can be measured through differencing processes to optimize fluorescence and reflectance spectra as needed. The main functional components of the instrument are a hyperspectral imager, an illumination system, and an image-plane scanner. The hyperspectral imager is a one-dimensional (line) imaging spectrometer that includes a spectrally dispersive element and a two-dimensional focal plane detector array. The spectral range of the current imaging spectrometer is between 400 to 1,000 nm, and the wavelength resolution is approximately 3 nm. The illumination system consists of narrowband blue, ultraviolet, and other discrete

  15. Optimal Current Transfer in Dendrites

    PubMed Central

    Bird, Alex D.

    2016-01-01

    Integration of synaptic currents across an extensive dendritic tree is a prerequisite for computation in the brain. Dendritic tapering away from the soma has been suggested to both equalise contributions from synapses at different locations and maximise the current transfer to the soma. To find out how this is achieved precisely, an analytical solution for the current transfer in dendrites with arbitrary taper is required. We derive here an asymptotic approximation that accurately matches results from numerical simulations. From this we then determine the diameter profile that maximises the current transfer to the soma. We find a simple quadratic form that matches diameters obtained experimentally, indicating a fundamental architectural principle of the brain that links dendritic diameters to signal transmission. PMID:27145441

  16. Remote sensing of ocean currents

    NASA Technical Reports Server (NTRS)

    Goldstein, R. M.; Zebker, H. A.; Barnett, T. P.

    1989-01-01

    A method of remotely measuring near-surface ocean currents with a synthetic aperture radar (SAR) is described. The apparatus consists of a single SAR transmitter and two receiving antennas. The phase difference between SAR image scenes obtained from the antennas forms an interferogram that is directly proportional to the surface current. The first field test of this technique against conventional measurements gives estimates of mean currents accurate to order 20 percent, that is, root-mean-square errors of 5 to 10 centimeters per second in mean flows of 27 to 56 centimeters per second. If the full potential of the method could be realized with spacecraft, then it might be possible to routinely monitor the surface currents of the world's oceans.

  17. Accurate determination of the complex refractive index of solid tissue-equivalent phantom

    NASA Astrophysics Data System (ADS)

    Wang, Jin; Ye, Qing; Deng, Zhichao; Zhou, Wenyuan; Zhang, Chunping; Tian, Jianguo

    2012-06-01

    Tissue-equivalent phantom is becoming widespread as a substitute in the biological field to verify optical theories, test measuring systems and study the tissue performances for varying boundary conditions, sample size and shape at a quantitative level. Compared with phantoms made with Intralipid solution, ink and other liquid substances, phantom in solid state is stable over time, reproducible, easy to handle and has been testified to be a suitable optical simulator in the visible and near-infrared region. We present accurate determination of the complex refractive index (RI) of a solid tissueequivalent phantom using extended derivative total reflection method (EDTRM). Scattering phantoms in solid state were measured for p-polarized and s-polarized incident light respectively. The reflectance curves of the sample as a function of incident angle were recorded. The real part of RI is directly determined by derivative of the reflectance curve, and the imaginary part is obtained from nonlinear fitting based on the Fresnel equation and Nelder-Mead simplex method. The EDTRM method is applicable for RI measurement of high scattering media such as biotissue, solid tissue-equivalent phantom and bulk material. The obtained RI information can be used in the study of tissue optics and biomedical field.

  18. Efficient construction of robust artificial neural networks for accurate determination of superficial sample optical properties.

    PubMed

    Chen, Yu-Wen; Tseng, Sheng-Hao

    2015-03-01

    In general, diffuse reflectance spectroscopy (DRS) systems work with photon diffusion models to determine the absorption coefficient μa and reduced scattering coefficient μs' of turbid samples. However, in some DRS measurement scenarios, such as using short source-detector separations to investigate superficial tissues with comparable μa and μs', photon diffusion models might be invalid or might not have analytical solutions. In this study, a systematic workflow of constructing a rapid, accurate photon transport model that is valid at short source-detector separations (SDSs) and at a wide range of sample albedo is revealed. To create such a model, we first employed a GPU (Graphic Processing Unit) based Monte Carlo model to calculate the reflectance at various sample optical property combinations and established a database at high speed. The database was then utilized to train an artificial neural network (ANN) for determining the sample absorption and reduced scattering coefficients from the reflectance measured at several SDSs without applying spectral constraints. The robustness of the produced ANN model was rigorously validated. We evaluated the performance of a successfully trained ANN using tissue simulating phantoms. We also determined the 500-1000 nm absorption and reduced scattering spectra of in-vivo skin using our ANN model and found that the values agree well with those reported in several independent studies. PMID:25798300

  19. 2010 CEOS Field Reflectance Intercomparisons Lessons Learned

    NASA Technical Reports Server (NTRS)

    Thome, Kurtis; Fox, Nigel

    2011-01-01

    This paper summarizes lessons learned from the 2009 and 2010 joint field campaigns to Tuz Golu, Turkey. Emphasis is placed on the 2010 campaign related to understanding the equipment and measurement protocols, processing schemes, and traceability to SI quantities. Participants in both 2009 and 2010 used an array of measurement approaches to determine surface reflectance. One lesson learned is that even with all of the differences in collection between groups, the differences in reflectance are currently dominated by instrumental artifacts including knowledge of the white reference. Processing methodology plays a limited role once the bi-directional reflectance of the white reference is used rather than a hemispheric-directional value. The lack of a basic set of measurement protocols, or best practices, limits a group s ability to ensure SI traceability and the development of proper error budgets. Finally, rigorous attention to sampling methodology and its impact on instrument behavior is needed. The results of the 2009 and 2010 joint campaigns clearly demonstrate both the need and utility of such campaigns and such comparisons must continue in the future to ensure a coherent set of data that can span multiple sensor types and multiple decades.

  20. Implosion Source Development and Diego Garcia Reflections

    SciTech Connect

    Harben, P E; Boro, C

    2001-06-01

    with a back-azimuth from Diego Garcia between 100 and 140 degrees. The Diego Garcia records show a pronounced reflection that correlates in travel time and back-azimuth (calculated using the waveform cross-correlation of the tri-partite array elements to determine lag time across the array) with a reflector at the Saya de Malha Bank, on the Seychelles-Mauritius Plateau. We also show that to accurately predict blockage and reflection regions, it is essential to have detailed bathymetry in relatively small but critical areas.