Science.gov

Sample records for effect background correction

  1. Vegetation index correction to reduce background effects in orchards with high spatial resolution imagery

    NASA Astrophysics Data System (ADS)

    Van Beek, Jonathan; Tits, Laurent; Somers, Ben; Deckers, Tom; Janssens, Pieter; Coppin, Pol

    2014-10-01

    High spatial resolution satellite imagery provides an alternative for time consuming and labor intensive in situ measurements of biophysical variables, such as chlorophyll and water content. However, despite the high spatial resolution of current satellite sensors, mixtures of canopies and backgrounds will be present, hampering the estimation of biophysical variables. Traditional correction methodologies use spectral differences between canopies and backgrounds, but fail with spectrally similar canopies and backgrounds. In this study, the lack of a generic solution to reduce background effects is tackled. Through synthetic imagery, the mixture problem was demonstrated with regards to the estimation of biophysical variables. A correction method was proposed, rescaling vegetation indices based on the canopy cover fraction. Furthermore, the proposed method was compared to traditional background correction methodologies (i.e. soil-adjusted vegetation indices and signal unmixing) for different background scenarios. The results of a soil background scenario showed the inability of soil-adjusted vegetation indices to reduce background admixture effects, while signal unmixing and the proposed method removed background influences for chlorophyll (ΔR2 = ~0.3; ΔRMSE = ~1.6 μg/cm2) and water (ΔR2 = ~0.3; ΔRMSE = ~0.5 mg/cm2) related vegetation indices. For the weed background scenario, signal unmixing was unable to remove the background influences for chlorophyll content (ΔR2 = -0.1; ΔRMSE = -0.6 μg/cm 2 ), while the proposed correction method reduced background effects (ΔR2= 0.1; ΔRMSE = 0.4 μg/cm2). Overall, the proposed vegetation index correction method reduced the background influence irrespective of background type, making useful comparison between management blocks possible.

  2. Improved Background Corrections for Uranium Holdup Measurements

    SciTech Connect

    Oberer, R.B.; Gunn, C.A.; Chiang, L.G.

    2004-06-21

    In the original Generalized Geometry Holdup (GGH) model, all holdup deposits were modeled as points, lines, and areas[1, 5]. Two improvements[4] were recently made to the GGH model and are currently in use at the Y-12 National Security Complex. These two improvements are the finite-source correction CF{sub g} and the self-attenuation correction. The finite-source correction corrects the average detector response for the width of point and line geometries which in effect, converts points and lines into areas. The result of a holdup measurement of an area deposit is a density-thickness which is converted to mass by multiplying it by the area of the deposit. From the measured density-thickness, the true density-thickness can be calculated by correcting for the material self-attenuation. Therefore the self-attenuation correction is applied to finite point and line deposits as well as areas. This report demonstrates that the finite-source and self-attenuation corrections also provide a means to better separate the gamma rays emitted by the material from the gamma rays emitted by background sources for an improved background correction. Currently, the measured background radiation is attenuated for equipment walls in the case of area deposits but not for line and point sources. The measured background radiation is not corrected for attenuation by the uranium material. For all of these cases, the background is overestimated which causes a negative bias in the measurement. The finite-source correction and the self-attenuation correction will allow the correction of the measured background radiation for both the equipment attenuation and material attenuation for area sources as well as point and line sources.

  3. No Influence of Indy on Lifespan in Drosophila after Correction for Genetic and Cytoplasmic Background Effects

    PubMed Central

    Toivonen, Janne M; Walker, Glenda A; Martinez-Diaz, Pedro; Bjedov, Ivana; Driege, Yasmine; Jacobs, Howard T; Gems, David; Partridge, Linda

    2007-01-01

    To investigate whether alterations in mitochondrial metabolism affect longevity in Drosophila melanogaster, we studied lifespan in various single gene mutants, using inbred and outbred genetic backgrounds. As positive controls we included the two most intensively studied mutants of Indy, which encodes a Drosophila Krebs cycle intermediate transporter. It has been reported that flies heterozygous for these Indy mutations, which lie outside the coding region, show almost a doubling of lifespan. We report that only one of the two mutants lowers mRNA levels, implying that the lifespan extension observed is not attributable to the Indy mutations themselves. Moreover, neither Indy mutation extended lifespan in female flies in any genetic background tested. In the original genetic background, only the Indy mutation associated with altered RNA expression extended lifespan in male flies. However, this effect was abolished by backcrossing into standard outbred genetic backgrounds, and was associated with an unidentified locus on the X chromosome. The original Indy line with long-lived males is infected by the cytoplasmic symbiont Wolbachia, and the longevity of Indy males disappeared after tetracycline clearance of this endosymbiont. These findings underscore the critical importance of standardisation of genetic background and of cytoplasm in genetic studies of lifespan, and show that the lifespan extension previously claimed for Indy mutants was entirely attributable to confounding variation from these two sources. In addition, we saw no effects on lifespan of expression knockdown of the Indy orthologues nac-2 and nac-3 in the nematode Caenorhabditis elegans. PMID:17571923

  4. Holographic Schwinger effect in a confining background with Gauss-Bonnet corrections

    NASA Astrophysics Data System (ADS)

    Zhang, Shao-Jun; Abdalla, E.

    2016-05-01

    We study the effect of higher-derivative terms on holographic Schwinger effect by introducing the Gauss-Bonnet term in the gravity sector. Anti-de Sitter soliton background is considered which is dual to confining phase of the boundary field theory. By calculating the potential between the produced pair, we find that larger Gauss-Bonnet factor λ makes the pair lighter. We apply numerical method to calculate the production rate for various cases. The results show that the Gauss-Bonnet term enhances the production rate. The critical behaviors near the two critical values of the electric field are also investigated, and it is found that the two critical indexes are not affected by the Gauss-Bonnet term and thus suggests a possible universality.

  5. Effect of background thermal radiation on radiative correction to elastic scattering of electrons

    SciTech Connect

    Zaleski, H. )

    1989-11-01

    Calculations of the energy dependence of the electron-scattering cross section in the presence of thermal background radiation (Planck's field) are done in the semiclassical approximation. It is shown that the cross section remains finite and is peaked around the initial energy with the width proportional to the radiation temperature.

  6. [The validation of the effect of correcting spectral background changes based on floating reference method by simulation].

    PubMed

    Wang, Zhu-lou; Zhang, Wan-jie; Li, Chen-xi; Chen, Wen-liang; Xu, Ke-xin

    2015-02-01

    There are some challenges in near-infrared non-invasive blood glucose measurement, such as the low signal to noise ratio of instrument, the unstable measurement conditions, the unpredictable and irregular changes of the measured object, and etc. Therefore, it is difficult to extract the information of blood glucose concentrations from the complicated signals accurately. Reference measurement method is usually considered to be used to eliminate the effect of background changes. But there is no reference substance which changes synchronously with the anylate. After many years of research, our research group has proposed the floating reference method, which is succeeded in eliminating the spectral effects induced by the instrument drifts and the measured object's background variations. But our studies indicate that the reference-point will changes following the changing of measurement location and wavelength. Therefore, the effects of floating reference method should be verified comprehensively. In this paper, keeping things simple, the Monte Carlo simulation employing Intralipid solution with the concentrations of 5% and 10% is performed to verify the effect of floating reference method used into eliminating the consequences of the light source drift. And the light source drift is introduced through varying the incident photon number. The effectiveness of the floating reference method with corresponding reference-points at different wavelengths in eliminating the variations of the light source drift is estimated. The comparison of the prediction abilities of the calibration models with and without using this method shows that the RMSEPs of the method are decreased by about 98.57% (5%Intralipid)and 99.36% (10% Intralipid)for different Intralipid. The results indicate that the floating reference method has obvious effect in eliminating the background changes. PMID:25970930

  7. COMPARISON BETWEEN ZEEMAN AND CONTINUUM BACKGROUND CORRECTION FOR GRAPHITE FURNACE AAS ON ENVIRONMENTAL SAMPLES

    EPA Science Inventory

    A comparison study was carried out to evaluate the two most commonly used background correction techniques in furnace atomic absorption spectroscopy, the Zeeman effect and continuum source background correction. Synthetic sample matrices were prepared consisting of the most frequ...

  8. Laser line illumination scheme allowing the reduction of background signal and the correction of absorption heterogeneities effects for fluorescence reflectance imaging.

    PubMed

    Fantoni, Frédéric; Hervé, Lionel; Poher, Vincent; Gioux, Sylvain; Mars, Jérôme I; Dinten, Jean-Marc

    2015-10-01

    Intraoperative fluorescence imaging in reflectance geometry is an attractive imaging modality as it allows to noninvasively monitor the fluorescence targeted tumors located below the tissue surface. Some drawbacks of this technique are the background fluorescence decreasing the contrast and absorption heterogeneities leading to misinterpretations concerning fluorescence concentrations. We propose a correction technique based on a laser line scanning illumination scheme. We scan the medium with the laser line and acquire, at each position of the line, both fluorescence and excitation images. We then use the finding that there is a relationship between the excitation intensity profile and the background fluorescence one to predict the amount of signal to subtract from the fluorescence images to get a better contrast. As the light absorption information is contained both in fluorescence and excitation images, this method also permits us to correct the effects of absorption heterogeneities. This technique has been validated on simulations and experimentally. Fluorescent inclusions are observed in several configurations at depths ranging from 1 mm to 1 cm. Results obtained with this technique are compared with those obtained with a classical wide-field detection scheme for contrast enhancement and with the fluorescence by an excitation ratio approach for absorption correction. PMID:26442963

  9. Passive background correction method for spatially resolved detection

    DOEpatents

    Schmitt, Randal L.; Hargis, Jr., Philip J.

    2011-05-10

    A method for passive background correction during spatially or angularly resolved detection of emission that is based on the simultaneous acquisition of both the passive background spectrum and the spectrum of the target of interest.

  10. 40 CFR 1065.667 - Dilution air background emission correction.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ...) AIR POLLUTION CONTROLS ENGINE-TESTING PROCEDURES Calculations and Data Requirements § 1065.667 Dilution air background emission correction. (a) To determine the mass of background emissions to subtract... 40 Protection of Environment 33 2011-07-01 2011-07-01 false Dilution air background...

  11. 40 CFR 1065.667 - Dilution air background emission correction.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ...) AIR POLLUTION CONTROLS ENGINE-TESTING PROCEDURES Calculations and Data Requirements § 1065.667 Dilution air background emission correction. (a) To determine the mass of background emissions to subtract... 40 Protection of Environment 34 2012-07-01 2012-07-01 false Dilution air background...

  12. 40 CFR 1065.667 - Dilution air background emission correction.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ...) AIR POLLUTION CONTROLS ENGINE-TESTING PROCEDURES Calculations and Data Requirements § 1065.667 Dilution air background emission correction. (a) To determine the mass of background emissions to subtract... 40 Protection of Environment 32 2010-07-01 2010-07-01 false Dilution air background...

  13. 40 CFR 1065.667 - Dilution air background emission correction.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ...) AIR POLLUTION CONTROLS ENGINE-TESTING PROCEDURES Calculations and Data Requirements § 1065.667 Dilution air background emission correction. (a) To determine the mass of background emissions to subtract... 40 Protection of Environment 33 2014-07-01 2014-07-01 false Dilution air background...

  14. 40 CFR 1065.667 - Dilution air background emission correction.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ...) AIR POLLUTION CONTROLS ENGINE-TESTING PROCEDURES Calculations and Data Requirements § 1065.667 Dilution air background emission correction. (a) To determine the mass of background emissions to subtract... 40 Protection of Environment 34 2013-07-01 2013-07-01 false Dilution air background...

  15. Investigation of chemical modifiers for the determination of lead in fertilizers and limestone using graphite furnace atomic absorption spectrometry with Zeeman-effect background correction and slurry sampling

    NASA Astrophysics Data System (ADS)

    Borges, Aline R.; Becker, Emilene M.; Dessuy, Morgana B.; Vale, Maria Goreti R.; Welz, Bernhard

    2014-02-01

    In this work, chemical modifiers in solution (Pd/Mg, NH4H2PO4 and NH4NO3/Pd) were compared with permanent modifiers (Ir and Ru) for the determination of lead in fertilizer and limestone samples using slurry sampling and graphite furnace atomic absorption spectrometry with Zeeman-effect background correction. The analytical line at 283.3 nm was used due to some spectral interference observed at 217.0 nm. The NH4H2PO4 was abandoned due to severe spectral interference even at the 283.3-nm line. For Pd/Mg and NH4NO3/Pd the optimum pyrolysis and atomization temperatures were 900 °C and 1900 °C, respectively. For Ru and Ir, the integrated absorbance signal was stable up to pyrolysis temperatures of 700 °C and 900 °C, respectively, and up to atomization temperature of 1700 °C. The limit of detection (LOD) was 17 ng g- 1 using Pd/Mg and 29 ng g- 1 using NH4NO3/Pd. Among the permanent modifiers investigated, the LOD was 22 ng g- 1 Pb for Ir and 10 ng g- 1 Pb for Ru. The accuracy of the method was evaluated using the certified reference material NIST SRM 695. Although Ru provided lower LOD, which can be attributed to a lower blank signal, only the modifiers in solution showed concordant values of Pb concentration for the NIST SRM 695 and the most of analyzed samples. Moreover, the Pd/Mg modifier provided the highest sensitivity and for this reason it is more suitable for the determination of Pb in fertilizers samples in slurry; besides this it presented a better signal-to-noise ratio than NH4NO3/Pd.

  16. 40 CFR 1066.610 - Dilution air background correction.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... POLLUTION CONTROLS VEHICLE-TESTING PROCEDURES Calculations § 1066.610 Dilution air background correction. (a... ratio of the test fuel. You may measure a or use default values from Table 1 of 40 CFR 1065.655. b... 40 CFR 1065.655. ER28AP14.101 (c) Determine the dilution factor, DF, over the test interval...

  17. Background correction using dinucleotide affinities improves the performance of GCRMA

    PubMed Central

    Gharaibeh, Raad Z; Fodor, Anthony A; Gibas, Cynthia J

    2008-01-01

    Background High-density short oligonucleotide microarrays are a primary research tool for assessing global gene expression. Background noise on microarrays comprises a significant portion of the measured raw data, which can have serious implications for the interpretation of the generated data if not estimated correctly. Results We introduce an approach to calculate probe affinity based on sequence composition, incorporating nearest-neighbor (NN) information. Our model uses position-specific dinucleotide information, instead of the original single nucleotide approach, and adds up to 10% to the total variance explained (R2) when compared to the previously published model. We demonstrate that correcting for background noise using this approach enhances the performance of the GCRMA preprocessing algorithm when applied to control datasets, especially for detecting low intensity targets. Conclusion Modifying the previously published position-dependent affinity model to incorporate dinucleotide information significantly improves the performance of the model. The dinucleotide affinity model enhances the detection of differentially expressed genes when implemented as a background correction procedure in GeneChip preprocessing algorithms. This is conceptually consistent with physical models of binding affinity, which depend on the nearest-neighbor stacking interactions in addition to base-pairing. PMID:18947404

  18. Background electrolyte correction for electrokinetic sonic amplitude measurements

    SciTech Connect

    Desai, F.N.; Hammad, H.R.; Hayes, K.F. )

    1993-11-01

    Electroacoustics has recently been used to measure electrokinetic properties of colloidal systems. When an alternating electric field is applied to a colloidal suspension, charged particles in the liquid will move electrophoretically and create an alternating pressure wave. The electrokinetic sonic amplitude (ESA), which is the pressure amplitude per unit electric field, is related to the electrophoretic mobility and [zeta] potential. For a solid suspension in an electrolyte solution, the measured ESA signal is a combination of two signals: one for the solid and the other for the background electrolyte. Under certain operating conditions, the contribution from the background electrolyte signal is not negligible and must be subtracted from the measured value to arrive at the particle ESA value. Background electrolyte corrections were performed on a Geltech silica and a US Silica no. 40 quartz at two ionic strengths (0.01 and 0.1 M NaCl) covering the pH range 2-8. These corrections are important at high ionic strengths because the ESA signal for the solid decreases and the background signal increases with increasing ionic strength. 12 refs., 11 figs.

  19. Star formation history, dust correction, and the extragalactic background light

    NASA Astrophysics Data System (ADS)

    Khaire, Vikram; Srianand, Raghunathan

    2016-01-01

    The intensity of the extragalactic background light (EBL) from X-rays to infrared wavelengths is of a fundamental importance to study the physics of the intergalactic medium and the distant γ-ray sources. At any given epoch, it carries an imprint of the integrated cosmic star formation rate and quasar activity till that epoch. The EBL cannot be observed directly because of its low surface brightness beyond the local universe and one has to rely on the theoretical estimates. To obtain the EBL theoretically, one requires an accurate estimate of the cosmic star formation rate density (SFRD), and the quasar emissivity. The estimates of SFRD are known to be degenerate with the amount of dust correction. To resolve this degeneracy, we present a novel 'progressive fitting method', which uses observed multi-wavelength and multi-epoch galaxy luminosity function measurements and determines a unique combination of the average SFRD(z) and dust attenuation AFUV(z) in the far ultraviolet band (FUV band; central wavelength~1500 Angstrom) for a given extinction curve. Using this method and the available observations, we determine the combinations of SFRD(z) and AFUV(z) up to z~8 for five well known extinction curves. The comparison with the independent SFRD(z), AFUV(z) and local infrared emissivity measurements from the literature with our predictions favor an extinction curve similar to that of Large Magellanic Cloud Supershell (LMC2). We update the quasar emissivity using the recent quasar luminosity function (QLF) measurements which show a factor of ~2 increase as compared to the previous QLFs at z<2. We show, the EBL estimated using this updated quasar emissivity and the SFRD(z) for LMC2 extinction curve resolves the problem of 'photon underproduction crisis' at low redshift. The EBL consistently reproduces the recent measurements of γ-ray horizon and the pair-production optical depths of γ-rays from the Fermi Large Area Telescope. The effect of the updated EBL on the

  20. Quantum scalar corrections to the gravitational potentials on de Sitter background

    NASA Astrophysics Data System (ADS)

    Park, Sohyun; Prokopec, Tomislav; Woodard, R. P.

    2016-01-01

    We employ the graviton self-energy induced by a massless, minimally coupled (MMC) scalar on de Sitter background to compute the quantum corrections to the gravitational potentials of a static point particle with a mass M . The Schwinger-Keldysh formalism is used to derive real and causal effective field equations. When evaluated at the one-loop order, the gravitational potentials exhibit a secular decrease in the observed gravitational coupling G. This can also be interpreted as a (time dependent) anti-screening of the mass M.

  1. Born-corrections to weak lensing of the cosmic microwave background temperature and polarization anisotropies

    NASA Astrophysics Data System (ADS)

    Hagstotz, Steffen; Schäfer, Björn Malte; Merkel, Philipp M.

    2015-11-01

    Many weak-lensing calculations make use of the Born approximation where the light ray is approximated by a straight path. We examine the effect of Born-corrections for lensing of the cosmic microwave background (CMB) in an analytical approach by taking perturbative corrections to the geodesic into account. The resulting extra power in the lensing potential spectrum is comparable to the power generated by non-linear structure formation and affects especially the polarization spectra, leading to relative changes of the order of 10-3 for the E-mode spectrum and several per cent on all scales to the B-mode spectrum. In contrast, there is only little change of spectra involving the CMB temperature. Additionally, the corrections excite one more degree of freedom resulting in a deflection component which cannot be described as a gradient of the lensing potential as it is related to image rotation in lens-lens coupling. We estimate the magnitude of this effect on the CMB spectra and find it to be negligible.

  2. Background on Wisconsin's Prison and Community Corrections System. Staff Brief 86-4.

    ERIC Educational Resources Information Center

    Bogar, Anne; Shannon, Pam

    This report was prepared for the Wisconsin State Legislative Council's Special Committee on Community Corrections Issues. It provides background information on the Wisconsin prison system for adults and the Wisconsin community corrections system for adults. Part I examines the prison system, focusing on administration of the system, sentencing…

  3. Background intensity correction for terabyte-sized time-lapse images.

    PubMed

    Chalfoun, J; Majurski, M; Bhadriraju, K; Lund, S; Bajcsy, P; Brady, M

    2015-03-01

    Several computational challenges associated with large-scale background image correction of terabyte-sized fluorescent images are discussed and analysed in this paper. Dark current, flat-field and background correction models are applied over a mosaic of hundreds of spatially overlapping fields of view (FOVs) taken over the course of several days, during which the background diminishes as cell colonies grow. The motivation of our work comes from the need to quantify the dynamics of OCT-4 gene expression via a fluorescent reporter in human stem cell colonies. Our approach to background correction is formulated as an optimization problem over two image partitioning schemes and four analytical correction models. The optimization objective function is evaluated in terms of (1) the minimum root mean square (RMS) error remaining after image correction, (2) the maximum signal-to-noise ratio (SNR) reached after downsampling and (3) the minimum execution time. Based on the analyses with measured dark current noise and flat-field images, the most optimal GFP background correction is obtained by using a data partition based on forming a set of submosaic images with a polynomial surface background model. The resulting image after correction is characterized by an RMS of about 8, and an SNR value of a 4 × 4 downsampling above 5 by Rose criterion. The new technique generates an image with half RMS value and double SNR value when compared to an approach that assumes constant background throughout the mosaic. We show that the background noise in terabyte-sized fluorescent image mosaics can be corrected computationally with the optimized triplet (data partition, model, SNR driven downsampling) such that the total RMS value from background noise does not exceed the magnitude of the measured dark current noise. In this case, the dark current noise serves as a benchmark for the lowest noise level that an imaging system can achieve. In comparison to previous work, the past fluorescent

  4. Enhancement of seminal stains using background correction algorithm with colour filters.

    PubMed

    Lee, Wee Chuen; Khoo, Bee Ee; Abdullah, Ahmad Fahmi Lim

    2016-06-01

    Evidence in crime scenes available in the form of biological stains which cannot be visualized during naked eye examination can be detected by imaging their fluorescence using a combination of excitation lights and suitable filters. These combinations selectively allow the passage of fluorescence light emitted from the targeted stains. However, interference from the fluorescence generated by many of the surface materials bearing the stains often renders it difficult to visualize the stains during forensic photography. This report describes the use of background correction algorithm (BCA) to enhance the visibility of seminal stain, a biological evidence that fluoresces. While earlier reports described the use of narrow band-pass filters for other fluorescing evidences, here, we utilize BCA to enhance images captured using commonly available colour filters, yellow, orange and red. Mean-based contrast adjustment was incorporated into BCA to adjust the background brightness for achieving similarity of images' background appearance, a crucial step for ensuring success while implementing BCA. Experiment results demonstrated the effectiveness of our proposed colour filters' approach using the improved BCA in enhancing the visibility of seminal stains in varying dilutions on selected surfaces. PMID:27061146

  5. Simple automatic strategy for background drift correction in chromatographic data analysis.

    PubMed

    Fu, Hai-Yan; Li, He-Dong; Yu, Yong-Jie; Wang, Bing; Lu, Peng; Cui, Hua-Peng; Liu, Ping-Ping; She, Yuan-Bin

    2016-06-01

    Chromatographic background drift correction, which influences peak detection and time shift alignment results, is a critical stage in chromatographic data analysis. In this study, an automatic background drift correction methodology was developed. Local minimum values in a chromatogram were initially detected and organized as a new baseline vector. Iterative optimization was then employed to recognize outliers, which belong to the chromatographic peaks, in this vector, and update the outliers in the baseline until convergence. The optimized baseline vector was finally expanded into the original chromatogram, and linear interpolation was employed to estimate background drift in the chromatogram. The principle underlying the proposed method was confirmed using a complex gas chromatographic dataset. Finally, the proposed approach was applied to eliminate background drift in liquid chromatography quadrupole time-of-flight samples used in the metabolic study of Escherichia coli samples. The proposed method was comparable with three classical techniques: morphological weighted penalized least squares, moving window minimum value strategy and background drift correction by orthogonal subspace projection. The proposed method allows almost automatic implementation of background drift correction, which is convenient for practical use. PMID:27139215

  6. Estimation of Organ Activity using Four Different Methods of Background Correction in Conjugate View Method.

    PubMed

    Shanei, Ahmad; Afshin, Maryam; Moslehi, Masoud; Rastaghi, Sedighe

    2015-01-01

    To make an accurate estimation of the uptake of radioactivity in an organ using the conjugate view method, corrections of physical factors, such as background activity, scatter, and attenuation are needed. The aim of this study was to evaluate the accuracy of four different methods for background correction in activity quantification of the heart in myocardial perfusion scans. The organ activity was calculated using the conjugate view method. A number of 22 healthy volunteers were injected with 17-19 mCi of (99m)Tc-methoxy-isobutyl-isonitrile (MIBI) at rest or during exercise. Images were obtained by a dual-headed gamma camera. Four methods for background correction were applied: (1) Conventional correction (referred to as the Gates' method), (2) Buijs method, (3) BgdA subtraction, (4) BgdB subtraction. To evaluate the accuracy of these methods, the results of the calculations using the above-mentioned methods were compared with the reference results. The calculated uptake in the heart using conventional method, Buijs method, BgdA subtraction, and BgdB subtraction methods was 1.4 ± 0.7% (P < 0.05), 2.6 ± 0.6% (P < 0.05), 1.3 ± 0.5% (P < 0.05), and 0.8 ± 0.3% (P < 0.05) of injected dose (I.D) at rest and 1.8 ± 0.6% (P > 0.05), 3.1 ± 0.8% (P > 0.05), 1.9 ± 0.8% (P < 0.05), and 1.2 ± 0.5% (P < 0.05) of I.D, during exercise. The mean estimated myocardial uptake of (99m)Tc-MIBI was dependent on the correction method used. Comparison among the four different methods of background activity correction applied in this study showed that the Buijs method was the most suitable method for background correction in myocardial perfusion scan. PMID:26955568

  7. ENmix: a novel background correction method for Illumina HumanMethylation450 BeadChip

    PubMed Central

    Xu, Zongli; Niu, Liang; Li, Leping; Taylor, Jack A.

    2016-01-01

    The Illumina HumanMethylation450 BeadChip is increasingly utilized in epigenome-wide association studies, however, this array-based measurement of DNA methylation is subject to measurement variation. Appropriate data preprocessing to remove background noise is important for detecting the small changes that may be associated with disease. We developed a novel background correction method, ENmix, that uses a mixture of exponential and truncated normal distributions to flexibly model signal intensity and uses a truncated normal distribution to model background noise. Depending on data availability, we employ three approaches to estimate background normal distribution parameters using (i) internal chip negative controls, (ii) out-of-band Infinium I probe intensities or (iii) combined methylated and unmethylated intensities. We evaluate ENmix against other available methods for both reproducibility among duplicate samples and accuracy of methylation measurement among laboratory control samples. ENmix out-performed other background correction methods for both these measures and substantially reduced the probe-design type bias between Infinium I and II probes. In reanalysis of existing EWAS data we show that ENmix can identify additional CpGs, and results in smaller P-value estimates for previously-validated CpGs. We incorporated the method into R package ENmix, which is freely available from Bioconductor website. PMID:26384415

  8. Efficient Photometry In-Frame Calibration (EPIC) Gaussian Corrections for Automated Background Normalization of Rate-Tracked Satellite Imagery

    NASA Astrophysics Data System (ADS)

    Griesbach, J.; Wetterer, C.; Sydney, P.; Gerber, J.

    Photometric processing of non-resolved Electro-Optical (EO) images has commonly required the use of dark and flat calibration frames that are obtained to correct for charge coupled device (CCD) dark (thermal) noise and CCD quantum efficiency/optical path vignetting effects respectively. It is necessary to account/calibrate for these effects so that the brightness of objects of interest (e.g. stars or resident space objects (RSOs)) may be measured in a consistent manner across the CCD field of view. Detected objects typically require further calibration using aperture photometry to compensate for sky background (shot noise). For this, annuluses are measured around each detected object whose contained pixels are used to estimate an average background level that is subtracted from the detected pixel measurements. In a new photometric calibration software tool developed for AFRL/RD, called Efficient Photometry In-Frame Calibration (EPIC), an automated background normalization technique is proposed that eliminates the requirement to capture dark and flat calibration images. The proposed technique simultaneously corrects for dark noise, shot noise, and CCD quantum efficiency/optical path vignetting effects. With this, a constant detection threshold may be applied for constant false alarm rate (CFAR) object detection without the need for aperture photometry corrections. The detected pixels may be simply summed (without further correction) for an accurate instrumental magnitude estimate. The noise distribution associated with each pixel is assumed to be sampled from a Poisson distribution. Since Poisson distributed data closely resembles Gaussian data for parameterized means greater than 10, the data may be corrected by applying bias subtraction and standard-deviation division. EPIC performs automated background normalization on rate-tracked satellite images using the following technique. A deck of approximately 50-100 images is combined by performing an independent median

  9. A background correction algorithm for Van Allen Probes MagEIS electron flux measurements

    SciTech Connect

    Claudepierre, S. G.; O'Brien, T. P.; Blake, J. B.; Fennell, J. F.; Roeder, J. L.; Clemmons, J. H.; Looper, M. D.; Mazur, J. E.; Mulligan, T. M.; Spence, H. E.; Reeves, G. D.; Friedel, R. H. W.; Henderson, M. G.; Larsen, B. A.

    2015-07-14

    We describe an automated computer algorithm designed to remove background contamination from the Van Allen Probes Magnetic Electron Ion Spectrometer (MagEIS) electron flux measurements. We provide a detailed description of the algorithm with illustrative examples from on-orbit data. We find two primary sources of background contamination in the MagEIS electron data: inner zone protons and bremsstrahlung X-rays generated by energetic electrons interacting with the spacecraft material. Bremsstrahlung X-rays primarily produce contamination in the lower energy MagEIS electron channels (~30–500 keV) and in regions of geospace where multi-M eV electrons are present. Inner zone protons produce contamination in all MagEIS energy channels at roughly L < 2.5. The background-corrected MagEIS electron data produce a more accurate measurement of the electron radiation belts, as most earlier measurements suffer from unquantifiable and uncorrectable contamination in this harsh region of the near-Earth space environment. These background-corrected data will also be useful for spacecraft engineering purposes, providing ground truth for the near-Earth electron environment and informing the next generation of spacecraft design models (e.g., AE9).

  10. A background correction algorithm for Van Allen Probes MagEIS electron flux measurements

    DOE PAGESBeta

    Claudepierre, S. G.; O'Brien, T. P.; Blake, J. B.; Fennell, J. F.; Roeder, J. L.; Clemmons, J. H.; Looper, M. D.; Mazur, J. E.; Mulligan, T. M.; Spence, H. E.; et al

    2015-07-14

    We describe an automated computer algorithm designed to remove background contamination from the Van Allen Probes Magnetic Electron Ion Spectrometer (MagEIS) electron flux measurements. We provide a detailed description of the algorithm with illustrative examples from on-orbit data. We find two primary sources of background contamination in the MagEIS electron data: inner zone protons and bremsstrahlung X-rays generated by energetic electrons interacting with the spacecraft material. Bremsstrahlung X-rays primarily produce contamination in the lower energy MagEIS electron channels (~30–500 keV) and in regions of geospace where multi-M eV electrons are present. Inner zone protons produce contamination in all MagEIS energymore » channels at roughly L < 2.5. The background-corrected MagEIS electron data produce a more accurate measurement of the electron radiation belts, as most earlier measurements suffer from unquantifiable and uncorrectable contamination in this harsh region of the near-Earth space environment. These background-corrected data will also be useful for spacecraft engineering purposes, providing ground truth for the near-Earth electron environment and informing the next generation of spacecraft design models (e.g., AE9).« less

  11. A robust background correction algorithm for forensic bloodstain imaging using mean-based contrast adjustment.

    PubMed

    Lee, Wee Chuen; Khoo, Bee Ee; Abdullah, Ahmad Fahmi Lim

    2016-05-01

    Background correction algorithm (BCA) is useful in enhancing the visibility of images captured in crime scenes especially those of untreated bloodstains. Successful implementation of BCA requires all the images to have similar brightness which often proves a problem when using automatic exposure setting in a camera. This paper presents an improved background correction algorithm (BCA) that applies mean-based contrast adjustment as a pre-correction step to adjust the mean brightness of images to be similar before implementing BCA. The proposed modification, namely mean-based adaptive BCA (mABCA) was tested on various image samples captured under different illuminations such as 385 nm, 415 nm and 458 nm. We also evaluated mABCA of two wavelengths (415 nm and 458 nm) and three wavelengths (415 nm, 380 nm and 458 nm) in enhancing untreated bloodstains on different surfaces. The proposed mABCA is found to be more robust in processing images captured in different brightness and thus overcomes the main issue faced in the original BCA. PMID:27162018

  12. Aircraft and background noise annoyance effects

    NASA Technical Reports Server (NTRS)

    Willshire, K. F.

    1984-01-01

    To investigate annoyance of multiple noise sources, two experiments were conducted. The first experiment, which used 48 subjects, was designed to establish annoyance-noise level functions for three community noise sources presented individually: jet aircraft flyovers, air conditioner, and traffic. The second experiment, which used 216 subjects, investigated the effects of background noise on aircraft annoyance as a function of noise level and spectrum shape; and the differences between overall, aircraft, and background noise annoyance. In both experiments, rated annoyance was the dependent measure. Results indicate that the slope of the linear relationship between annoyance and noise level for traffic is significantly different from that of flyover and air conditioner noise and that further research was justified to determine the influence of the two background noises on overall, aircraft, and background noise annoyance (e.g., experiment two). In experiment two, total noise exposure, signal-to-noise ratio, and background source type were found to have effects on all three types of annoyance. Thus, both signal-to-noise ratio, and the background source must be considered when trying to determine community response to combined noise sources.

  13. Empirical Correction of Crosstalk in a Low-Background Germanium γ–γ Analysis System

    SciTech Connect

    Keillor, Martin E.; Erikson, Luke E.; Aalseth, Craig E.; Day, Anthony R.; Fuller, Erin S.; Glasgow, Brian D.; Hoppe, Eric W.; Hossbach, Todd W.; Mizouni, Leila K.; Myers, Allan W.; Overman, Cory T.; Seifert, Allen; Stavenger, Timothy J.

    2013-05-01

    ABSTRACT The Pacific Northwest National Laboratory is currently developing a custom software suite capable of automating many of the tasks required to accurately analyze coincident signals within gamma spectrometer arrays. During the course of this work, significant crosstalk was identified in the energy determination for spectra collected with a new low-background intrinsic germanium (HPGe) array at PNNL. The HPGe array is designed for high detection efficiency, ultra-low-background performance, and sensitive gamma gamma coincidence detection. The first half of the array, a single cryostat containing 7 HPGe crystals, was recently installed into a new shallow underground laboratory facility. This update will present a brief review of the germanium array, describe the observed crosstalk, and present a straight-forward empirical correction that significantly reduces the impact of this crosstalk on the spectroscopic performance of the system.

  14. Background corrections for laser-induced-fluorescence measurements of nitric oxide in lean, high-pressure, premixed methane flames.

    PubMed

    Thomsen, D D; Kuligowski, F F; Laurendeau, N M

    1997-05-20

    An experimental technique is presented that both minimizes and accounts for the interference background when laser-induced-fluorescence (LIF) measurements are made of NO in lean, high-pressure, premixed, CH(4)/O(2)/N(2) flames. Measurement interferences such as fluorescence and Raman scattering from secondary species become increasingly important for high-pressure LIF studies. O(2) fluorescence interferences are particularly troublesome in lean premixed flames. An excitation-detection scheme that minimizes the effects of these interferences is identified. A procedure that corrects the resulting LIF signal so as to account for any remaining interference signal is then developed. This correction is found to vary from less than 10% of the overall NO signal at atmospheric pressure to over 40% of the overall signal at 14.6 atm for LIF measurements of NO in a series of worst-case flames (phi = 0.6, dilution ratio 2.2). The correction technique is further demonstrated to be portable over a useful range of flame conditions at each pressure. PMID:18253332

  15. Corrective Action Site 02-37-02 Background Information and Comparison to Corrective Action Site 09-99-06

    SciTech Connect

    2012-06-26

    Corrective Action Site (CAS) 02-37-02, Gas Sampling Assembly, is associated with nuclear test MULLET. MULLET was an underground safety test conducted on October 17, 1963. The experiment also involved prompt sampling of particulate material from the detonation, similar to CAS 09-99-06, Gas Sampling Assembly, which is associated with PLAYER/YORK. The sampling system at MULLET was similar to that of PLAYER/YORK and was used to convey gas from the MULLET emplacement hole (U2ag) to a sampling assembly. Beyond the sampling assembly, the system had a 'Y' junction with one branch running to a filter unit and the other running to a scrubber unit. The total system length was approximately 250 feet and is depicted on the attached drawing. According to the available background information, retrieval of the sample material from the MULLET event caused significant alpha (plutonium) contamination, limited to an area near ground zero (GZ). Test support Radiological Control Technicians did not detect contamination outside the immediate GZ area. In addition, vehicles, equipment, and workers that were contaminated were decontaminated on site. Soil contamination was addressed through the application of oil, and the site was decommissioned after the test. Any equipment that could be successfully decontaminated and had a future use was removed from the site. The contaminated equipment and temporary buildings erected to support the test were buried on site, most likely in the area under the dirt berm. The exact location of the buried equipment and temporary buildings is unknown. No information was found describing the disposition of the filter and scrubber, but they are not known to be at the site. The COMMODORE test was conducted at U2am on May 20, 1967, and formed the crater next to CAS 02-37-02. The COMMODORE test area had been surveyed prior to the test, and alpha contamination was not identified. Furthermore, alpha contamination was not identified during the COMMODORE re

  16. Solar background effects in wireless optical communications

    NASA Astrophysics Data System (ADS)

    Sidorovich, Vladimir G.

    2002-12-01

    In free-space optical (FSO) communications, conditions may be met when laser links suffer from solar background radiation (SBR). There are four types of such conditions Direct sunlight hitting a photodetector Reflected sunlight (glints) Sunlight scattered by hydrometeors Sunlight scattered by surrounding objects (walls, etc.) Direct sunlight may cause total break of communications (link outage), and thus affect the link availability. However, experiments prove that the sunlight does not cause irreversible degradation of semiconductor photodetectors used in FSO systems. Estimations are made of the link outage periods duration for various types of SBR conditions, also other effects caused by SBR have been considered. Recommendations are presented for the link directivity optimization to avoid (or to minimize the probability of) communication interrupts caused by SBR. A nomographic chart has been developed to forecast periods of time when direct or scattered solar radiation may cause link outage. With this chart, a user in any point of the globe, knowing the link orientation (azimuth and elevation angles), can see when and for how long (if at all) may the link operation be affected by unfavorable SBR conditions, also in many cases it is possible to recommend insignificant modifications in the link orientation causing material improvement in FSO system performance.

  17. Effect of background electrolytes on gypsum dissolution

    NASA Astrophysics Data System (ADS)

    Burgos-Cara, Alejandro; Putnis, Christine; Ruiz-Agudo, Encarnacion

    2015-04-01

    Knowledge of the dissolution behaviour of gypsum (CaSO4· 2H2O) in aqueous solutions is of primary importance in many natural and technological processes (Pachon-Rodriguez and Colombani, 2007), including the weathering of rocks and gypsum karst formations, deformation of gypsum-bearing rocks, the quality of drinking water, amelioration of soil acidity, scale formation in the oil and gas industry or measurement of water motion in oceanography. Specific ions in aqueous solutions can play important but very different roles on mineral dissolution. For example, the dissolution rates and the morphology of dissolution features may be considerably modified by the presence of the foreign ions in the solution, which adsorb at the surface and hinder the detachment of the ions building the crystal. Dissolution processes in the aqueous environment are closely related to the rearrangement of water molecules around solute ions and the interaction between the solvent molecules themselves. The rearrangement of water molecules with respect to solute species has been recognized as the main kinetic barrier for crystal dissolution in many systems (Davis, 2000; De Yoreo and Dove 2004; Wasylenki et al. 2005). Current research suggest that the control that electrolytes exert on water structure is limited to the local environment surrounding the ions and is not related to long-range electric fields emanating from the ions but results from effects associated with the hydration shell(s) of the ions (Collins et al. 2007) and the ions' capacity to break or structure water (i.e. chaotropic and kosmotropic ions, respectively). These effects will ultimately affect the kinetics of crystal dissolution, and could be correlated with the water affinity of the respective background ions following a trend known as the lyotropic or Hofmeister series (Kunz et al. 2004; Dove and Craven, 2005). In situ macroscopic and Atomic Force Microscopy (AFM) flow-through dissolution experiments were conducted at a

  18. Electroweak Sudakov Corrections using Effective Field Theory

    SciTech Connect

    Chiu Juiyu; Golf, Frank; Kelley, Randall; Manohar, Aneesh V.

    2008-01-18

    Electroweak Sudakov corrections of the form {alpha}{sup n}log{sup m}s/M{sub W,Z}{sup 2} are summed using renormalization group evolution in soft-collinear effective theory. Results are given for the scalar, vector, and tensor form factors for fermion and scalar particles. The formalism for including massive gauge bosons in soft-collinear effective theory is developed.

  19. Determination of serum aluminum by electrothermal atomic absorption spectrometry: A comparison between Zeeman and continuum background correction systems

    NASA Astrophysics Data System (ADS)

    Kruger, Pamela C.; Parsons, Patrick J.

    2007-03-01

    Excessive exposure to aluminum (Al) can produce serious health consequences in people with impaired renal function, especially those undergoing hemodialysis. Al can accumulate in the brain and in bone, causing dialysis-related encephalopathy and renal osteodystrophy. Thus, dialysis patients are routinely monitored for Al overload, through measurement of their serum Al. Electrothermal atomic absorption spectrometry (ETAAS) is widely used for serum Al determination. Here, we assess the analytical performances of three ETAAS instruments, equipped with different background correction systems and heating arrangements, for the determination of serum Al. Specifically, we compare (1) a Perkin Elmer (PE) Model 3110 AAS, equipped with a longitudinally (end) heated graphite atomizer (HGA) and continuum-source (deuterium) background correction, with (2) a PE Model 4100ZL AAS equipped with a transversely heated graphite atomizer (THGA) and longitudinal Zeeman background correction, and (3) a PE Model Z5100 AAS equipped with a HGA and transverse Zeeman background correction. We were able to transfer the method for serum Al previously established for the Z5100 and 4100ZL instruments to the 3110, with only minor modifications. As with the Zeeman instruments, matrix-matched calibration was not required for the 3110 and, thus, aqueous calibration standards were used. However, the 309.3-nm line was chosen for analysis on the 3110 due to failure of the continuum background correction system at the 396.2-nm line. A small, seemingly insignificant overcorrection error was observed in the background channel on the 3110 instrument at the 309.3-nm line. On the 4100ZL, signal oscillation was observed in the atomization profile. The sensitivity, or characteristic mass ( m0), for Al at the 309.3-nm line on the 3110 AAS was found to be 12.1 ± 0.6 pg, compared to 16.1 ± 0.7 pg for the Z5100, and 23.3 ± 1.3 pg for the 4100ZL at the 396.2-nm line. However, the instrumental detection limits (3

  20. GafChromic EBT film dosimetry with flatbed CCD scanner: A novel background correction method and full dose uncertainty analysis

    SciTech Connect

    Saur, Sigrun; Frengen, Jomar

    2008-07-15

    Film dosimetry using radiochromic EBT film in combination with a flatbed charge coupled device scanner is a useful method both for two-dimensional verification of intensity-modulated radiation treatment plans and for general quality assurance of treatment planning systems and linear accelerators. Unfortunately, the response over the scanner area is nonuniform, and when not corrected for, this results in a systematic error in the measured dose which is both dose and position dependent. In this study a novel method for background correction is presented. The method is based on the subtraction of a correction matrix, a matrix that is based on scans of films that are irradiated to nine dose levels in the range 0.08-2.93 Gy. Because the response of the film is dependent on the film's orientation with respect to the scanner, correction matrices for both landscape oriented and portrait oriented scans were made. In addition to the background correction method, a full dose uncertainty analysis of the film dosimetry procedure was performed. This analysis takes into account the fit uncertainty of the calibration curve, the variation in response for different film sheets, the nonuniformity after background correction, and the noise in the scanned films. The film analysis was performed for film pieces of size 16x16 cm, all with the same lot number, and all irradiations were done perpendicular onto the films. The results show that the 2-sigma dose uncertainty at 2 Gy is about 5% and 3.5% for landscape and portrait scans, respectively. The uncertainty gradually increases as the dose decreases, but at 1 Gy the 2-sigma dose uncertainty is still as good as 6% and 4% for landscape and portrait scans, respectively. The study shows that film dosimetry using GafChromic EBT film, an Epson Expression 1680 Professional scanner and a dedicated background correction technique gives precise and accurate results. For the purpose of dosimetric verification, the calculated dose distribution can

  1. Finite nucleus effects on relativistic energy corrections

    NASA Technical Reports Server (NTRS)

    Dyall, Kenneth G.; Faegri, Knut, Jr.

    1993-01-01

    The effect of using a finite nucleus model in quantum-chemical calculations is examined. Relativistic corrections from the first order Foldy-Wouthuysen terms are affected indirectly by the change in wavefunction, but also directly as a result of revised expressions for the Darwin and spin-orbit terms due to the change in nuclear potential. A calculation for the Rn atom indicates that the mass-velocity and Darwin corrections are much more sensitive to the finite nucleus than the non-relativistic total energy, but that the total contribution for these two terms is quite stable provided the revised form of the Darwin term is used. The spin-orbit interaction is not greatly affected by the choice of nuclear model.

  2. The Effect of Focused Written Corrective Feedback and Language Aptitude on ESL Learners' Acquisition of Articles

    ERIC Educational Resources Information Center

    Sheen, Younghee

    2007-01-01

    This study examines the differential effect of two types of written corrective feedback (CF) and the extent to which language analytic ability mediates the effects of CF on the acquisition of articles by adult intermediate ESL learners of various L1 backgrounds (N = 91). Three groups were formed: a "direct-only correction" group, a "direct…

  3. Environmental context effects of background color in free recall.

    PubMed

    Isarida, Taeo; Isarin, Tosmko K

    2007-10-01

    In four experiments, we investigated background-color context effects in free recall. A total of 194 undergraduates studied words presented one by one against a background color, and oral free recall was tested after a 30-sec filled retention interval. A signal for recall was presented against a background color throughout the test. Recalled items were classified as same- and different-context items according to whether the background colors at study and test were the same or different. Significant context effects were found in Experiments I and 2, in which two background colors were randomly alternated word by word. No context effects were found in Experiments 3 and 4, in which a common background color was presented for all items (Experiment 3) or for a number of successive items (Experiment 4). The results indicate that a change in background colors is necessary and sufficient to produce context effects. Implications of the present findings are discussed. PMID:18062540

  4. Electroweak Corrections to pp→μ^{+}μ^{-}e^{+}e^{-}+X at the LHC: A Higgs Boson Background Study.

    PubMed

    Biedermann, B; Denner, A; Dittmaier, S; Hofer, L; Jäger, B

    2016-04-22

    The first complete calculation of the next-to-leading-order electroweak corrections to four-lepton production at the LHC is presented, where all off-shell effects of intermediate Z bosons and photons are taken into account. Focusing on the mixed final state μ^{+}μ^{-}e^{+}e^{-}, we study differential cross sections that are particularly interesting for Higgs boson analyses. The electroweak corrections are divided into photonic and purely weak corrections. The former exhibit patterns familiar from similar W- or Z-boson production processes with very large radiative tails near resonances and kinematical shoulders. The weak corrections are of the generic size of 5% and show interesting variations, in particular, a sign change between the regions of resonant Z-pair production and the Higgs signal. PMID:27152792

  5. Electroweak Corrections to p p →μ+μ-e+e-+X at the LHC: A Higgs Boson Background Study

    NASA Astrophysics Data System (ADS)

    Biedermann, B.; Denner, A.; Dittmaier, S.; Hofer, L.; Jäger, B.

    2016-04-01

    The first complete calculation of the next-to-leading-order electroweak corrections to four-lepton production at the LHC is presented, where all off-shell effects of intermediate Z bosons and photons are taken into account. Focusing on the mixed final state μ+μ-e+e-, we study differential cross sections that are particularly interesting for Higgs boson analyses. The electroweak corrections are divided into photonic and purely weak corrections. The former exhibit patterns familiar from similar W - or Z -boson production processes with very large radiative tails near resonances and kinematical shoulders. The weak corrections are of the generic size of 5% and show interesting variations, in particular, a sign change between the regions of resonant Z -pair production and the Higgs signal.

  6. A generalised background correction algorithm for a Halo Doppler lidar and its application to data from Finland

    DOE PAGESBeta

    Manninen, Antti J.; O'Connor, Ewan J.; Vakkari, Ville; Petäjä, Tuukka

    2016-03-03

    Current commercially available Doppler lidars provide an economical and robust solution for measuring vertical and horizontal wind velocities, together with the ability to provide co- and cross-polarised backscatter profiles. The high temporal resolution of these instruments allows turbulent properties to be obtained from studying the variation in radial velocities. However, the instrument specifications mean that certain characteristics, especially the background noise behaviour, become a limiting factor for the instrument sensitivity in regions where the aerosol load is low. Turbulent calculations require an accurate estimate of the contribution from velocity uncertainty estimates, which are directly related to the signal-to-noise ratio. Anymore » bias in the signal-to-noise ratio will propagate through as a bias in turbulent properties. In this paper we present a method to correct for artefacts in the background noise behaviour of commercially available Doppler lidars and reduce the signal-to-noise ratio threshold used to discriminate between noise, and cloud or aerosol signals. Lastly, we show that, for Doppler lidars operating continuously at a number of locations in Finland, the data availability can be increased by as much as 50 % after performing this background correction and subsequent reduction in the threshold. The reduction in bias also greatly improves subsequent calculations of turbulent properties in weak signal regimes.« less

  7. A generalised background correction algorithm for a Halo Doppler lidar and its application to data from Finland

    NASA Astrophysics Data System (ADS)

    Manninen, Antti J.; O'Connor, Ewan J.; Vakkari, Ville; Petäjä, Tuukka

    2016-03-01

    Current commercially available Doppler lidars provide an economical and robust solution for measuring vertical and horizontal wind velocities, together with the ability to provide co- and cross-polarised backscatter profiles. The high temporal resolution of these instruments allows turbulent properties to be obtained from studying the variation in radial velocities. However, the instrument specifications mean that certain characteristics, especially the background noise behaviour, become a limiting factor for the instrument sensitivity in regions where the aerosol load is low. Turbulent calculations require an accurate estimate of the contribution from velocity uncertainty estimates, which are directly related to the signal-to-noise ratio. Any bias in the signal-to-noise ratio will propagate through as a bias in turbulent properties. In this paper we present a method to correct for artefacts in the background noise behaviour of commercially available Doppler lidars and reduce the signal-to-noise ratio threshold used to discriminate between noise, and cloud or aerosol signals. We show that, for Doppler lidars operating continuously at a number of locations in Finland, the data availability can be increased by as much as 50 % after performing this background correction and subsequent reduction in the threshold. The reduction in bias also greatly improves subsequent calculations of turbulent properties in weak signal regimes.

  8. String theory effective action; String loop corrections

    SciTech Connect

    Tseytlin, A.A. )

    1988-01-01

    The authors discuss the general ideology of the computation of string loop corrections to the effective action for the massless modes of the string. Both the S-matrix and the sigma-model approaches are presented. It is emphasized that the effective action is more general and better defined object than the S-matrix. In particular, it is finite in spite of modular infinities that may be present in loop amplitudes computed near a wrong vacuum. The case of the disc topology in the open-closed string theory is treated in some detail. Some issues concerning the soft dilation vertex operators related to the infinities of the string amplitudes are discussed.

  9. Effective Correctional Treatment: Bibliotherapy for Cynics.

    ERIC Educational Resources Information Center

    Gendreau, Paul; Ross, Bob

    1979-01-01

    Presents recent evidence, obtained from a review of the literature on correctional treatment published since 1973, appealing the verdict that correctional rehabilitation is ineffective. There are several types of intervention programs that have proved successful with offender populations. (Author)

  10. The Cosmic Microwave Background Radiation does NOT prove that the Hot Big Bang Theory is Correct

    NASA Astrophysics Data System (ADS)

    Bligh, B. R.

    2009-12-01

    It has frequently been asserted that the discovery of the Cosmic Microwave Background Radiation (CMB) by Penzias and Wilson is proof of the validity of the Hot Big Bang Theory of the origin of the Universe. In reality this is not the case because the expansion of the Universe at the time of the supposed "Fireball'' would not produce the perfect black-body radiation which is actually observed. This problem with the CMB has been pointed out before by Mitchell (1994) but the present study establishes the argument by means of rigorous thermodynamic calculations. The CMB is said to have been produced at the time of"de-coupling'' when the electron density in the primeval Universe was very small. The radiation generated at that epoch would have had a black-body spectrum. Three cases are analysed when the electron density approached zero; three appropriate temperatures are taken and then the thermodynamic properties -- including density -- are calculated for the three cases. These provide a measure of the expansion to the present day. Wien's law is applied to calculate the fall in temperature of the radiation for each case -- assuming that the black-body spectrum is maintained. According to the Hot Big Bang Theory the three cases should all arrive at 2.72 K, but they do not. The conclusion is that the CMB spectrum ought to be "smeared" and not the almost perfect black-body curve, which is actually observed. Therefore the Hot Big Bang Theory fails this test.

  11. AlphaSpectrum ASPECT analysis code for background correction & peak integration

    Energy Science and Technology Software Center (ESTSC)

    2005-04-13

    count time of the spectrum, sample volume represented, the total volume of air sampled by the filter, and other relevant data on the sample. Dummy variable assignments could be made in the code for all variables except for the alpha spectrum if the count rate, concentration, date stamp, and other outputs were not desired, but this option in not automatically available. The code could be implemented in an embedded form and thereby operate independently of user inputs. However, in the present version, the code is designed to operate off-line, accessing stored spectrum data (and other relevant sampling data) from stored files. In this form the user can select the characteristics of peak identification, the sigma-multiplier for the Critical Level determination, and whether or not the data are smoothed before analysis. This version is a development version, from which the user could prepare an embedded version not requiring operator intervention. In any case, the core program of peak identification, fitting, and interference correction is the same.« less

  12. AlphaSpectrum ASPECT analysis code for background correction & peak integration

    SciTech Connect

    Rodgers, John C.

    2005-04-13

    of the spectrum, sample volume represented, the total volume of air sampled by the filter, and other relevant data on the sample. Dummy variable assignments could be made in the code for all variables except for the alpha spectrum if the count rate, concentration, date stamp, and other outputs were not desired, but this option in not automatically available. The code could be implemented in an embedded form and thereby operate independently of user inputs. However, in the present version, the code is designed to operate off-line, accessing stored spectrum data (and other relevant sampling data) from stored files. In this form the user can select the characteristics of peak identification, the sigma-multiplier for the Critical Level determination, and whether or not the data are smoothed before analysis. This version is a development version, from which the user could prepare an embedded version not requiring operator intervention. In any case, the core program of peak identification, fitting, and interference correction is the same.

  13. Correction.

    PubMed

    2015-11-01

    In the article by Heuslein et al, which published online ahead of print on September 3, 2015 (DOI: 10.1161/ATVBAHA.115.305775), a correction was needed. Brett R. Blackman was added as the penultimate author of the article. The article has been corrected for publication in the November 2015 issue. PMID:26490278

  14. Effect of Listeners' Linguistic Background on Perceptual Judgements of Hypernasality

    ERIC Educational Resources Information Center

    Lee, Alice; Brown, Susanna; Gibbon, Fiona E.

    2008-01-01

    Background: Many speech and language therapists work in a multilingual environment, making cross-linguistic studies of speech disorders clinically and theoretically important. Aims: To investigate the effect of listeners' linguistic background on their perceptual ratings of hypernasality and the reliability of the ratings. Methods & Procedures:…

  15. Correction.

    PubMed

    2015-12-01

    In the article by Narayan et al (Narayan O, Davies JE, Hughes AD, Dart AM, Parker KH, Reid C, Cameron JD. Central aortic reservoir-wave analysis improves prediction of cardiovascular events in elderly hypertensives. Hypertension. 2015;65:629–635. doi: 10.1161/HYPERTENSIONAHA.114.04824), which published online ahead of print December 22, 2014, and appeared in the March 2015 issue of the journal, some corrections were needed.On page 632, Figure, panel A, the label PRI has been corrected to read RPI. In panel B, the text by the upward arrow, "10% increase in kd,” has been corrected to read, "10% decrease in kd." The corrected figure is shown below.The authors apologize for these errors. PMID:26558821

  16. Auditory intensity processing: Effect of MRI background noise.

    PubMed

    Angenstein, Nicole; Stadler, Jörg; Brechmann, André

    2016-03-01

    Studies on active auditory intensity discrimination in humans showed equivocal results regarding the lateralization of processing. Whereas experiments with a moderate background found evidence for right lateralized processing of intensity, functional magnetic resonance imaging (fMRI) studies with background scanner noise suggest more left lateralized processing. With the present fMRI study, we compared the task dependent lateralization of intensity processing between a conventional continuous echo planar imaging (EPI) sequence with a loud background scanner noise and a fast low-angle shot (FLASH) sequence with a soft background scanner noise. To determine the lateralization of the processing, we employed the contralateral noise procedure. Linearly frequency modulated (FM) tones were presented monaurally with and without contralateral noise. During both the EPI and the FLASH measurement, the left auditory cortex was more strongly involved than the right auditory cortex while participants categorized the intensity of FM tones. This was shown by a strong effect of the additional contralateral noise on the activity in the left auditory cortex. This means a massive reduction in background scanner noise still leads to a significant left lateralized effect. This suggests that the reversed lateralization in fMRI studies with loud background noise in contrast to studies with softer background cannot be fully explained by the MRI background noise. PMID:26778471

  17. Background, Schooling, and Achievement. Sustaining Effects Study Technical Report 20.

    ERIC Educational Resources Information Center

    Won, Eugene Y. T.; And Others

    This report of a study on the influence of education on student achievement finds that while schooling does have some tangible effects, they are not enough to significantly counterbalance the effects of students' social backgrounds. The report is part of an extensive series of studies on compensatory education and its long-term effects. The study…

  18. Laser-induced breakdown spectroscopy in gases using ungated detection in combination with polarization filtering and online background correction

    NASA Astrophysics Data System (ADS)

    Kiefer, J.; Tröger, J. W.; Seeger, T.; Leipertz, A.; Li, B.; Li, Z. S.; Aldén, M.

    2010-06-01

    Quantitative and fast analysis of gas mixtures is an important task in the field of chemical, security and environmental analysis. In this paper we present a diagnostic approach based on laser-induced breakdown spectroscopy (LIBS). A polarization filter in the signal collection system enables sufficient suppression of elastically scattered light which otherwise reduces the dynamic range of the measurement. Running the detector with a doubled repetition rate as compared to the laser online background correction is obtained. Quantitative measurements of molecular air components in synthetic, ambient and expiration air are performed and demonstrate the potential of the method. The detection limits for elemental oxygen and hydrogen are in the order of 15 ppm and 10 ppm, respectively.

  19. Correction

    NASA Astrophysics Data System (ADS)

    1995-04-01

    Seismic images of the Brooks Range, Arctic Alaska, reveal crustal-scale duplexing: Correction Geology, v. 23, p. 65 68 (January 1995) The correct Figure 4A, for the loose insert, is given here. See Figure 4A below. Corrected inserts will be available to those requesting copies of the article from the senior author, Gary S. Fuis, U.S. Geological Survey, 345 Middlefield Road, Menlo Park, CA 94025. Figure 4A. P-wave velocity model of Brooks Range region (thin gray contours) with migrated wide-angle reflections (heavy red lines) and migreated vertical-incidence reflections (short black lines) superimposed. Velocity contour interval is 0.25 km/s; 4,5, and 6 km/s contours are labeled. Estimated error in velocities is one contour interval. Symbols on faults shown at top are as in Figure 2 caption.

  20. Correction.

    PubMed

    2016-02-01

    Neogi T, Jansen TLTA, Dalbeth N, et al. 2015 Gout classification criteria: an American College of Rheumatology/European League Against Rheumatism collaborative initiative. Ann Rheum Dis 2015;74:1789–98. The name of the 20th author was misspelled. The correct spelling is Janitzia Vazquez-Mellado. We regret the error. PMID:26881284

  1. Background Speech Effects on Sentence Processing during Reading: An Eye Movement Study

    PubMed Central

    Hyönä, Jukka; Ekholm, Miia

    2016-01-01

    Effects of background speech on reading were examined by playing aloud different types of background speech, while participants read long, syntactically complex and less complex sentences embedded in text. Readers’ eye movement patterns were used to study online sentence comprehension. Effects of background speech were primarily seen in rereading time. In Experiment 1, foreign-language background speech did not disrupt sentence processing. Experiment 2 demonstrated robust disruption in reading as a result of semantically and syntactically anomalous scrambled background speech preserving normal sentence-like intonation. Scrambled speech that was constructed from the text to-be read did not disrupt reading more than scrambled speech constructed from a different, semantically unrelated text. Experiment 3 showed that scrambled speech exacerbated the syntactic complexity effect more than coherent background speech, which also interfered with reading. Experiment 4 demonstrated that both semantically and syntactically anomalous speech produced no more disruption in reading than semantically anomalous but syntactically correct background speech. The pattern of results is best explained by a semantic account that stresses the importance of similarity in semantic processing, but not similarity in semantic content, between the reading task and background speech. PMID:27003410

  2. Background Speech Effects on Sentence Processing during Reading: An Eye Movement Study.

    PubMed

    Hyönä, Jukka; Ekholm, Miia

    2016-01-01

    Effects of background speech on reading were examined by playing aloud different types of background speech, while participants read long, syntactically complex and less complex sentences embedded in text. Readers' eye movement patterns were used to study online sentence comprehension. Effects of background speech were primarily seen in rereading time. In Experiment 1, foreign-language background speech did not disrupt sentence processing. Experiment 2 demonstrated robust disruption in reading as a result of semantically and syntactically anomalous scrambled background speech preserving normal sentence-like intonation. Scrambled speech that was constructed from the text to-be read did not disrupt reading more than scrambled speech constructed from a different, semantically unrelated text. Experiment 3 showed that scrambled speech exacerbated the syntactic complexity effect more than coherent background speech, which also interfered with reading. Experiment 4 demonstrated that both semantically and syntactically anomalous speech produced no more disruption in reading than semantically anomalous but syntactically correct background speech. The pattern of results is best explained by a semantic account that stresses the importance of similarity in semantic processing, but not similarity in semantic content, between the reading task and background speech. PMID:27003410

  3. Effects of placement point of background music on shopping website.

    PubMed

    Lai, Chien-Jung; Chiang, Chia-Chi

    2012-01-01

    Consumer on-line behaviors are more important than ever due to highly growth of on-line shopping. The purposes of this study were to design placement methods of background music for shopping website and examine the effect on browsers' emotional and cognitive response. Three placement points of background music during the browsing, i.e. 2 min., 4 min., and 6 min. from the start of browsing were considered for entry points. Both browsing without music (no music) and browsing with constant music volume (full music) were treated as control groups. Participants' emotional state, approach-avoidance behavior intention, and action to adjust music volume were collected. Results showed that participants had a higher level of pleasure, arousal and approach behavior intention for the three placement points than for no music and full music. Most of the participants for full music (5/6) adjusted the background music. Only 16.7% (3/18) participants for other levels turn off the background music. The results indicate that playing background music after the start of browsing is benefit for on-line shopping atmosphere. It is inappropriate to place background music at the start of browsing shopping website. The marketer must manipulated placement methods of background music for a web store carefully. PMID:22317572

  4. Self-corrected elaboration and spacing effects in incidental memory.

    PubMed

    Toyota, Hiroshi

    2006-04-01

    The present study investigated the effect of self-corrected elaboration on incidental memory as a function of types of presentation (massed vs spaced) and sentence frames (image vs nonimage). The subjects were presented a target word and an incongruous sentence frame and asked to correct the target to make a common sentence in the self-corrected elaboration condition, whereas in the experimenter-corrected elaboration condition they were asked to rate the appropriateness of the congruous word presented, followed by free recall test. The superiority of the self-corrected elaboration to the experimenter-corrected elaboration was observed only in some situations of combinations by the types of presentation and sentence frames. These results were discussed in terms of the effectiveness of the self-corrected elaboration. PMID:16826672

  5. Correction.

    PubMed

    2016-02-01

    In the article by Guessous et al (Guessous I, Pruijm M, Ponte B, Ackermann D, Ehret G, Ansermot N, Vuistiner P, Staessen J, Gu Y, Paccaud F, Mohaupt M, Vogt B, Pechère-Bertschi A, Martin PY, Burnier M, Eap CB, Bochud M. Associations of ambulatory blood pressure with urinary caffeine and caffeine metabolite excretions. Hypertension. 2015;65:691–696. doi: 10.1161/HYPERTENSIONAHA.114.04512), which published online ahead of print December 8, 2014, and appeared in the March 2015 issue of the journal, a correction was needed.One of the author surnames was misspelled. Antoinette Pechère-Berstchi has been corrected to read Antoinette Pechère-Bertschi.The authors apologize for this error. PMID:26763012

  6. Multi-talker background and semantic priming effect

    PubMed Central

    Dekerle, Marie; Boulenger, Véronique; Hoen, Michel; Meunier, Fanny

    2014-01-01

    The reported studies have aimed to investigate whether informational masking in a multi-talker background relies on semantic interference between the background and target using an adapted semantic priming paradigm. In 3 experiments, participants were required to perform a lexical decision task on a target item embedded in backgrounds composed of 1–4 voices. These voices were Semantically Consistent (SC) voices (i.e., pronouncing words sharing semantic features with the target) or Semantically Inconsistent (SI) voices (i.e., pronouncing words semantically unrelated to each other and to the target). In the first experiment, backgrounds consisted of 1 or 2 SC voices. One and 2 SI voices were added in Experiments 2 and 3, respectively. The results showed a semantic priming effect only in the conditions where the number of SC voices was greater than the number of SI voices, suggesting that semantic priming depended on prime intelligibility and strategic processes. However, even if backgrounds were composed of 3 or 4 voices, reducing intelligibility, participants were able to recognize words from these backgrounds, although no semantic priming effect on the targets was observed. Overall this finding suggests that informational masking can occur at a semantic level if intelligibility is sufficient. Based on the Effortfulness Hypothesis, we also suggest that when there is an increased difficulty in extracting target signals (caused by a relatively high number of voices in the background), more cognitive resources were allocated to formal processes (i.e., acoustic and phonological), leading to a decrease in available resources for deeper semantic processing of background words, therefore preventing semantic priming from occurring. PMID:25400572

  7. Effect of background evolution on the curvaton non-Gaussianity

    SciTech Connect

    Enqvist, Kari; Takahashi, Tomo E-mail: tomot@cc.saga-u.ac.jp

    2009-12-01

    We investigate how the background evolution affects the curvature perturbations generated by the curvaton, assuming a curvaton potential that may deviate slightly from the quadratic one, and parameterizing the background fluid density as ρ∝a{sup −α}, where a is the scale factor, and α depends on the background fluid. It turns out that the more there is deviation from the quadratic case, the more pronounced is the dependence of the curvature perturbation on α. We also show that the background can have a significant effect on the nonlinearity parameters f{sub NL} and g{sub NL}. As an example, if at the onset of the curvaton oscillation there is a dimension 6 contribution to the potential at 5 % level and the energy fraction of the curvaton to the total one at the time of its decay is at 1%, we find variations Δf{sub NL} ∼ O(10) and Δg{sub NL} ∼ O(10{sup 4}) between matter and radiation dominated backgrounds. Moreover, we demonstrate that there is a relation between f{sub NL} and g{sub NL} that can be used to probe the form of the curvaton potential and the equation of state of the background fluid.

  8. Second Language Comprehensibility Revisited: Investigating the Effects of Learner Background

    ERIC Educational Resources Information Center

    Crowther, Dustin; Trofimovich, Pavel; Saito, Kazuya; Isaacs, Talia

    2015-01-01

    The current study investigated first language (L1) effects on listener judgment of comprehensibility and accentedness in second language (L2) speech. The participants were 45 university-level adult speakers of English from three L1 backgrounds (Chinese, Hindi, Farsi), performing a picture narrative task. Ten native English listeners used…

  9. The Effect of Background Music on Bullying: A Pilot Study

    ERIC Educational Resources Information Center

    Ziv, Naomi; Dolev, Einat

    2013-01-01

    School bullying is a source of growing concern. A number of intervention programs emphasize the importance of a positive school climate in preventing bullying behavior. The aim of the presented pilot study was to examine whether calming background music, through its effect on arousal and mood, could create a pleasant atmosphere and reduce bullying…

  10. A versatile microcomputer interface and peripheral devices: An application in deuterium lamp background correction graphite furnace atomic absorption spectrometry

    NASA Astrophysics Data System (ADS)

    Gökmen, A.; Yalcin, S.

    1992-01-01

    A versatile interface card for Apple IIe computer and various peripheral devices are designed to control instruments which generates transient signals like in graphite furnace atomic spectrometer. The interface card consists of a multiplexed analog-to-digital converter, a digital-to-analog converter, and a timer/counter chip. The timer/counter chip with 16 built-in registers can be programmed in many modes which provides a time base for real-time measurements. A stepper motor runs under the control of timer/counter chip independent of computer. A light chopper connected to the stepper motor is controlled easily by computer. A dual high-voltage switch can modulate dc light sources under computer control. This system is applied to D2-lamp background correction graphite furnace atomic absorption spectrometer. The D2 lamp is chopped by a mechanical chopper driven by a stepper motor and a hollow cathode lamp is modulated electronically. The data acquisition program is written in machine language and synchronization between light sources and computer is provided by chopper position signal through the interrupts. A sampling rate of 16 during a signal period at 50-Hz chopping frequency is found to be the optimum value. A large number of data collected during atomization period is compressed in machine code. This saved storage space and analysis time.

  11. Visual signal detection in structured backgrounds. II. Effects of contrast gain control, background variations, and white noise

    NASA Technical Reports Server (NTRS)

    Eckstein, M. P.; Ahumada, A. J. Jr; Watson, A. B.

    1997-01-01

    Studies of visual detection of a signal superimposed on one of two identical backgrounds show performance degradation when the background has high contrast and is similar in spatial frequency and/or orientation to the signal. To account for this finding, models include a contrast gain control mechanism that pools activity across spatial frequency, orientation and space to inhibit (divisively) the response of the receptor sensitive to the signal. In tasks in which the observer has to detect a known signal added to one of M different backgrounds grounds due to added visual noise, the main sources of degradation are the stochastic noise in the image and the suboptimal visual processing. We investigate how these two sources of degradation (contrast gain control and variations in the background) interact in a task in which the signal is embedded in one of M locations in a complex spatially varying background (structured background). We use backgrounds extracted from patient digital medical images. To isolate effects of the fixed deterministic background (the contrast gain control) from the effects of the background variations, we conduct detection experiments with three different background conditions: (1) uniform background, (2) a repeated sample of structured background, and (3) different samples of structured background. Results show that human visual detection degrades from the uniform background condition to the repeated background condition and degrades even further in the different backgrounds condition. These results suggest that both the contrast gain control mechanism and the background random variations degrade human performance in detection of a signal in a complex, spatially varying background. A filter model and added white noise are used to generate estimates of sampling efficiencies, an equivalent internal noise, an equivalent contrast-gain-control-induced noise, and an equivalent noise due to the variations in the structured background.

  12. Non-Gaussian microwave background fluctuations from nonlinear gravitational effects

    NASA Technical Reports Server (NTRS)

    Salopek, D. S.; Kunstatter, G. (Editor)

    1991-01-01

    Whether the statistics of primordial fluctuations for structure formation are Gaussian or otherwise may be determined if the Cosmic Background Explorer (COBE) Satellite makes a detection of the cosmic microwave-background temperature anisotropy delta T(sub CMB)/T(sub CMB). Non-Gaussian fluctuations may be generated in the chaotic inflationary model if two scalar fields interact nonlinearly with gravity. Theoretical contour maps are calculated for the resulting Sachs-Wolfe temperature fluctuations at large angular scales (greater than 3 degrees). In the long-wavelength approximation, one can confidently determine the nonlinear evolution of quantum noise with gravity during the inflationary epoch because: (1) different spatial points are no longer in causal contact; and (2) quantum gravity corrections are typically small-- it is sufficient to model the system using classical random fields. If the potential for two scalar fields V(phi sub 1, phi sub 2) possesses a sharp feature, then non-Gaussian fluctuations may arise. An explicit model is given where cold spots in delta T(sub CMB)/T(sub CMB) maps are suppressed as compared to the Gaussian case. The fluctuations are essentially scale-invariant.

  13. Correction.

    PubMed

    2015-05-22

    The Circulation Research article by Keith and Bolli (“String Theory” of c-kitpos Cardiac Cells: A New Paradigm Regarding the Nature of These Cells That May Reconcile Apparently Discrepant Results. Circ Res. 2015:116:1216-1230. doi: 10.1161/CIRCRESAHA.116.305557) states that van Berlo et al (2014) observed that large numbers of fibroblasts and adventitial cells, some smooth muscle and endothelial cells, and rare cardiomyocytes originated from c-kit positive progenitors. However, van Berlo et al reported that only occasional fibroblasts and adventitial cells derived from c-kit positive progenitors in their studies. Accordingly, the review has been corrected to indicate that van Berlo et al (2014) observed that large numbers of endothelial cells, with some smooth muscle cells and fibroblasts, and more rarely cardiomyocytes, originated from c-kit positive progenitors in their murine model. The authors apologize for this error, and the error has been noted and corrected in the online version of the article, which is available at http://circres.ahajournals.org/content/116/7/1216.full ( PMID:25999426

  14. Correction

    NASA Astrophysics Data System (ADS)

    1998-12-01

    Alleged mosasaur bite marks on Late Cretaceous ammonites are limpet (patellogastropod) home scars Geology, v. 26, p. 947 950 (October 1998) This article had the following printing errors: p. 947, Abstract, line 11, “sepia” should be “septa” p. 947, 1st paragraph under Introduction, line 2, “creep” should be “deep” p. 948, column 1, 2nd paragraph, line 7, “creep” should be “deep” p. 949, column 1, 1st paragraph, line 1, “creep” should be “deep” p. 949, column 1, 1st paragraph, line 5, “19774” should be “1977)” p. 949, column 1, 4th paragraph, line 7, “in particular” should be “In particular” CORRECTION Mammalian community response to the latest Paleocene thermal maximum: An isotaphonomic study in the northern Bighorn Basin, Wyoming Geology, v. 26, p. 1011 1014 (November 1998) An error appeared in the References Cited. The correct reference appears below: Fricke, H. C., Clyde, W. C., O'Neil, J. R., and Gingerich, P. D., 1998, Evidence for rapid climate change in North America during the latest Paleocene thermal maximum: Oxygen isotope compositions of biogenic phosphate from the Bighorn Basin (Wyoming): Earth and Planetary Science Letters, v. 160, p. 193 208.

  15. Effects of background gravity stimuli on gravity-controlled behavior

    NASA Technical Reports Server (NTRS)

    Mccoy, D. F.

    1976-01-01

    Physiological and developmental effects of altered gravity were researched. The stimulus properties of gravity have been found to possess reinforcing and aversive properties. Experimental approaches taken, used animals placed into fields of artificial gravity, in the form of parabolic or spiral centrifuges. Gravity preferences were noted and it was concluded that the psychophysics of gravity and background factors which support these behaviors should be further explored.

  16. The Effectiveness of Written Corrective Feedback in Teaching Beginning German

    ERIC Educational Resources Information Center

    Vyatkina, Nina

    2010-01-01

    This study explores the effectiveness of instructor-written corrective feedback for the improvement of writing accuracy by beginning college-level learners of German. The researcher investigated changes in error rates in six error categories in essay writing in correlation with three different corrective feedback types administered consistently…

  17. Investigation of artifacts caused by deuterium background correction in the determination of phosphorus by electrothermal atomization using high-resolution continuum source atomic absorption spectrometry

    NASA Astrophysics Data System (ADS)

    Dessuy, Morgana B.; Vale, Maria Goreti R.; Lepri, Fábio G.; Borges, Daniel L. G.; Welz, Bernhard; Silva, Márcia M.; Heitmann, Uwe

    2008-02-01

    The artifacts created in the measurement of phosphorus at the 213.6-nm non-resonance line by electrothermal atomic absorption spectrometry using line source atomic absorption spectrometry (LS AAS) and deuterium lamp background correction (D 2 BC) have been investigated using high-resolution continuum source atomic absorption spectrometry (HR-CS AAS). The absorbance signals and the analytical curves obtained by LS AAS without and with D 2 BC, and with HR-CS AAS without and with automatic correction for continuous background absorption, and also with least-squares background correction for molecular absorption with rotational fine structure were compared. The molecular absorption due to the suboxide PO that exhibits pronounced fine structure could not be corrected by the D 2 BC system, causing significant overcorrection. Among the investigated chemical modifiers, NaF, La, Pd and Pd + Ca, the Pd modifier resulted in the best agreement of the results obtained with LS AAS and HR-CS AAS. However, a 15% to 100% higher sensitivity, expressed as slope of the analytical curve, was obtained for LS AAS compared to HR-CS AAS, depending on the modifier. Although no final proof could be found, the most likely explanation is that this artifact is caused by a yet unidentified phosphorus species that causes a spectrally continuous absorption, which is corrected without problems by HR-CS AAS, but which is not recognized and corrected by the D 2 BC system of LS AAS.

  18. Non-perturbative corrections to the one-loop free energy induced by a massive scalar field on a stationary slowly varying in space gravitational background

    NASA Astrophysics Data System (ADS)

    Kalinichenko, Igor; Kazinski, Peter

    2014-08-01

    The explicit expressions for the one-loop non-perturbative corrections to the gravitational effective action induced by a scalar field on a stationary gravitational background are obtained both at zero and finite temperatures. The perturbative and non-perturbative contributions to the one-loop effective action are explicitly separated. It is proved that, after a suitable renormalization, the perturbative part of the effective action at zero temperature can be expressed in a covariant form solely in terms of the metric and its derivatives. This part coincides with the known large mass expansion of the one-loop effective action. The non-perturbative part of the renormalized one-loop effective action at zero temperature is proved to depend explicitly on the Killing vector defining the vacuum state of quantum fields. This part cannot be expressed in a covariant way through the metric and its derivatives alone. The implications of this result for the structure and symmetries of the effective action for gravity are discussed.

  19. Effects of background noise on total noise annoyance

    NASA Technical Reports Server (NTRS)

    Willshire, K. F.

    1987-01-01

    Two experiments were conducted to assess the effects of combined community noise sources on annoyance. The first experiment baseline relationships between annoyance and noise level for three community noise sources (jet aircraft flyovers, traffic and air conditioners) presented individually. Forty eight subjects evaluated the annoyance of each noise source presented at four different noise levels. Results indicated the slope of the linear relationship between annoyance and noise level for the traffic noise was significantly different from that of aircraft and of air conditioner noise, which had equal slopes. The second experiment investigated annoyance response to combined noise sources, with aircraft noise defined as the major noise source and traffic and air conditioner noise as background noise sources. Effects on annoyance of noise level differences between aircraft and background noise for three total noise levels and for both background noise sources were determined. A total of 216 subjects were required to make either total or source specific annoyance judgements, or a combination of the two, for a wide range of combined noise conditions.

  20. How to Correct a Task Error: Task-Switch Effects Following Different Types of Error Correction

    ERIC Educational Resources Information Center

    Steinhauser, Marco

    2010-01-01

    It has been proposed that switch costs in task switching reflect the strengthening of task-related associations and that strengthening is triggered by response execution. The present study tested the hypothesis that only task-related responses are able to trigger strengthening. Effects of task strengthening caused by error corrections were…

  1. Methods to Increase Educational Effectiveness in an Adult Correctional Setting.

    ERIC Educational Resources Information Center

    Kuster, Byron

    1998-01-01

    A correctional educator reflects on methods that improve instructional effectiveness. These include teacher-student collaboration, clear goals, student accountability, positive classroom atmosphere, high expectations, and mutual respect. (SK)

  2. Various background pattern-effect on saccadic suppression.

    PubMed

    Mitrani, L; Radil-Weiss, T; Yakimoff, N; Mateeff, S; Bozkov, V

    1975-09-01

    It has been proved that the saccadic suppression is a phenomenon closely related to the presence of contours and structures in the visual field. Experiments were performed to clarify whether the structured background influences the pattern of attention distribution (making the stimulus detection more difficult) or whether the elevation of visual threshold is due to the "masking' effect of the moving background image over the retina. Two types of backgrounds were used therefore: those with symbolic meaning in the processing of which "psychological' mechanisms are presumably involved like picture reproductions of famous painters and photographs of nudes, and those lacking semantic significance like computer figures composed of randomly distributed black and white squares with different grain expressed as the entropy of the pattern. The results show that saccadic suppression is primarily a consequence of peripheral mechanisms, probably of lateral inhibition in the visual field occurring in the presence of moving edges over the retina. Psychological factors have to be excluded as being fundamental for saccadic suppression. PMID:1199681

  3. Background fish feminization effects in European remote sites

    NASA Astrophysics Data System (ADS)

    Jarque, Sergio; Quirós, Laia; Grimalt, Joan O.; Gallego, Eva; Catalan, Jordi; Lackner, Reinhard; Piña, Benjamin

    2015-06-01

    Human activity has spread trace amounts of chemically stable endocrine-disrupting pollutants throughout the biosphere. These compounds have generated a background level of estrogenic activity that needs to be assessed. Fish are adequate sentinels for feminization effects as male specimens are more sensitive than humans to exogenous estrogenic compounds. High mountain lakes, the most distant environments of continental areas, only receive semi-volatile compounds from atmospheric deposition. We analyzed the expression levels of estrogen-regulated genes in male fish from these mountain lakes in Europe. Incipient feminization involving expression of estrogen receptor and zona radiata genes revealed a widespread diffuse estrogenic impact. This effect was correlated with the concentrations of some organochlorine compounds in fish and was consistent with the persistent occurrence of these tropospheric pollutants in the most remote planet regions. These results should be of general concern given the increasing endocrine disruption effects in human populations.

  4. Background fish feminization effects in European remote sites

    PubMed Central

    Jarque, Sergio; Quirós, Laia; Grimalt, Joan O.; Gallego, Eva; Catalan, Jordi; Lackner, Reinhard; Piña, Benjamin

    2015-01-01

    Human activity has spread trace amounts of chemically stable endocrine-disrupting pollutants throughout the biosphere. These compounds have generated a background level of estrogenic activity that needs to be assessed. Fish are adequate sentinels for feminization effects as male specimens are more sensitive than humans to exogenous estrogenic compounds. High mountain lakes, the most distant environments of continental areas, only receive semi-volatile compounds from atmospheric deposition. We analyzed the expression levels of estrogen-regulated genes in male fish from these mountain lakes in Europe. Incipient feminization involving expression of estrogen receptor and zona radiata genes revealed a widespread diffuse estrogenic impact. This effect was correlated with the concentrations of some organochlorine compounds in fish and was consistent with the persistent occurrence of these tropospheric pollutants in the most remote planet regions. These results should be of general concern given the increasing endocrine disruption effects in human populations. PMID:26061088

  5. Prominence oscillations: Effect of a time-dependent background temperature

    NASA Astrophysics Data System (ADS)

    Ballester, J. L.; Carbonell, M.; Soler, R.; Terradas, J.

    2016-06-01

    Context. Small amplitude oscillations in prominences have been known about for a long time, and from a theoretical point of view, these oscillations have been interpreted in terms of standing or propagating linear magnetohydrodynamic (MHD) waves. In general, these oscillations were studied by producing small perturbations in a background equilibrium with stationary physical properties. Aims: Taking into account that prominences are dynamic plasma structures, the assumption of a stationary equilibrium is not realistic. Therefore, our main aim is to study the effects produced by a non-stationary background on slow MHD waves, which could be responsible for prominence oscillations. Methods: Assuming that the radiation term is proportional to temperature and constant external heating, we have derived an expression for the temporal variation of the background temperature, which depends on the imbalance between heating and cooling processes. Furthermore, radiative losses, together with parallel thermal conduction, have also been included as damping mechanisms for the waves. Results: As temperature increases with time, the period of slow waves decreases and the amplitude of the velocity perturbations is damped. The inclusion of radiative losses enhances the damping. As temperature decreases with time, the period of slow waves increases and the amplitude of velocity perturbations grows while, as expected, the inclusion of radiative losses contributes to the damping of oscillations. Conclusions: There is observational evidence that, in different locations of the same prominence, oscillations are damped or amplified with time. This temporal damping or amplification can be obtained by a proper combination of a variable background temperature, together with radiative damping. Furthermore, decayless oscillations can also be obtained with an appropriate choice of the characteristic radiation time.

  6. Display conditions and lesion detectability: effect of background light

    NASA Astrophysics Data System (ADS)

    Razavi, Mahmood; Hall, Theodore R.; Aberle, Denise R.; Hayrapetian, Alek S.; Loloyan, Mansur; Eldredge, Sandra L.

    1990-08-01

    We assessed the effect of high background light on observer performance for the detection of a variety of chest radiographic abnormalities. Five observers reviewed 66 digital hard copy chest images formatted to 1 1 x 14 inch size under two display conditions: 1) on a specially prepared 1 1 x 14 inch illuminated panel with no peripheral light and 2) on a standard viewing panel designed for 14 x 17 inch radiographs. The images contained one - or more of the following conditions: pneumothorax, interstitial disease, nodules, alveolar process, or no abnormality. The results of receiver operator characteristic analysis show that extraneous light does reduce observer performance and the detectability of nodules, interstitial disease.

  7. Temporal behavior of peripheral organ distribution volume in mammillary systems. II. Application to background correction in separate glomerular filtration rate estimation in man

    SciTech Connect

    Decostre, P.L.; Salmon, Y. )

    1990-10-01

    An original approach to background subtraction is presented for 99mTc-DTPA separate glomerular filtration rate (SGFR) estimation in man. The method is based on the properties of the peripheral organ distribution volume (PODV) in mammillary systems. These PODV properties allow easy separation of the components of the renogram, i.e., interstitial fluid, plasma and renal activities. The proposed algorithm takes advantage of the linear time dependence of the kidney distribution volume, during the renal uptake phase, to correct for the plasma residual activity, which always remains after classical background correction. Theoretically, the ratio between kidney uptake and SGFR should be identical for both left and right kidneys, even for very asymmetrical kidney functions. This is best verified when the proposed plasma residual activity correction is applied.

  8. Heel effect adaptive flat field correction of digital x-ray detectors

    SciTech Connect

    Yu, Yongjian; Wang, Jue

    2013-08-15

    Purpose: Anode heel effect renders large-scale background nonuniformities in digital radiographs. Conventional offset/gain calibration is performed at mono source-to-image distance (SID), and disregards the SID-dependent characteristic of heel effect. It results in a residual nonuniform background in the corrected radiographs when the SID settings for calibration and correction differ. In this work, the authors develop a robust and efficient computational method for digital x-ray detector gain correction adapted to SID-variant heel effect, without resorting to physical filters, phantoms, complicated heel effect models, or multiple-SID calibration and interpolation.Methods: The authors present the Duo-SID projection correction method. In our approach, conventional offset/gain calibrations are performed only twice, at the minimum and maximum SIDs of the system in typical clinical use. A fast iterative separation algorithm is devised to extract the detector gain and basis heel patterns from the min/max SID calibrations. The resultant detector gain is independent of SID, while the basis heel patterns are parameterized by the min- and max-SID. The heel pattern at any SID is obtained from the min-SID basis heel pattern via projection imaging principles. The system gain desired at a specific acquisition SID is then constructed using the projected heel pattern and detector gain map.Results: The method was evaluated for flat field and anatomical phantom image corrections. It demonstrated promising improvements over interpolation and conventional gain calibration/correction methods, lowering their correction errors by approximately 70% and 80%, respectively. The separation algorithm was able to extract the detector gain and heel patterns with less than 2% error, and the Duo-SID corrected images showed perceptually appealing uniform background across the detector.Conclusions: The Duo-SID correction method has substantially improved on conventional offset/gain corrections for

  9. A New Angle on Object-Background Effects in Vection.

    PubMed

    Kim, Juno; Tran, Michael T T

    2016-03-01

    We considered whether optic flow generated by 3D relief of a foreground surface might influence visually-mediated self-motion perception (vection). We generated background motion consistent with self-rotation, and a foreground object with bumpy relief was either rotated with the observer (ego-centric) or fixed in world coordinates (world-centric). We found that vection strength ratings were greater in conditions with world-centric retinal motion of the foreground object, despite generating flow that was opposite to background motion. This effect was explained by observer judgments of the axis self-rotation in depth; whereas ego-centric flow generated experiences of more on-axis self-rotation, world-centric flow generated experiences of centrifugal rotation around the foreground object. These data suggest that foreground object motion can increase the perception of self-motion generated by optic flow, even when they reduce net retinal motion coherence and promote conditions for multisensory conflict. This finding supports the view that self-motion perception depends on mid-level representations of whole-scene motion. PMID:27433322

  10. A New Angle on Object-Background Effects in Vection

    PubMed Central

    Tran, Michael T. T.

    2016-01-01

    We considered whether optic flow generated by 3D relief of a foreground surface might influence visually-mediated self-motion perception (vection). We generated background motion consistent with self-rotation, and a foreground object with bumpy relief was either rotated with the observer (ego-centric) or fixed in world coordinates (world-centric). We found that vection strength ratings were greater in conditions with world-centric retinal motion of the foreground object, despite generating flow that was opposite to background motion. This effect was explained by observer judgments of the axis self-rotation in depth; whereas ego-centric flow generated experiences of more on-axis self-rotation, world-centric flow generated experiences of centrifugal rotation around the foreground object. These data suggest that foreground object motion can increase the perception of self-motion generated by optic flow, even when they reduce net retinal motion coherence and promote conditions for multisensory conflict. This finding supports the view that self-motion perception depends on mid-level representations of whole-scene motion. PMID:27433322

  11. Comparison of Accuracy in Calculation of Absorbed Dose to Patients Following Bone Scan with (99m)Tc-Marked Diphosphonates by Two Different Background Correction Methods.

    PubMed

    Shahbazi-Gahrouei, Daryoush; Damoori, Mehri; Tavakoli, Mohammad Bagher; Moslehi, Masoud

    2016-01-01

    To improve the accuracy of the activity quantification and the image quality in scintigraphy, scatter correction is a vital procedure. The aim of this study is to compare the accuracy in calculation of absorbed dose to patients following bone scan with (99m)Tc-marked diphosphonates ((99m)Tc-MDP) by two different methods of background correction in conjugate view method. This study involved 22 patients referring to the Nuclear Medicine Center of Shahid Chamran Hospital, Isfahan, Iran. After the injection of (99m)Tc-MDP, whole-body images from patients were acquired at 10, 60, 90, and 180 min. Organ activities were calculated using the conjugate view method by Buijs and conventional background correction. Finally, the absorbed dose was calculated using the Medical Internal Radiation Dosimetry (MIRD) technique. The results of this study showed that the absorbed dose per unit of injected activity (rad/mCi) ± standard deviation for pelvis bone, bladder, and kidneys by Buijs method was 0.19 ± 0.05, 0.08 ± 0.01, and 0.03 ± 0.01 and by conventional method was 0.13 ± 0.04, 0.08 ± 0.01, and 0.024 ± 0.01, respectively. This showed that Buijs background correction method had a high accuracy compared to conventional method for the estimated absorbed dose of bone and kidneys whereas, for the bladder, its accuracy was low. PMID:27014610

  12. Comparison of Accuracy in Calculation of Absorbed Dose to Patients Following Bone Scan with 99mTc-Marked Diphosphonates by Two Different Background Correction Methods

    PubMed Central

    Shahbazi-Gahrouei, Daryoush; Damoori, Mehri; Tavakoli, Mohammad Bagher; Moslehi, Masoud

    2016-01-01

    To improve the accuracy of the activity quantification and the image quality in scintigraphy, scatter correction is a vital procedure. The aim of this study is to compare the accuracy in calculation of absorbed dose to patients following bone scan with 99mTc-marked diphosphonates (99mTc-MDP) by two different methods of background correction in conjugate view method. This study involved 22 patients referring to the Nuclear Medicine Center of Shahid Chamran Hospital, Isfahan, Iran. After the injection of 99mTc-MDP, whole-body images from patients were acquired at 10, 60, 90, and 180 min. Organ activities were calculated using the conjugate view method by Buijs and conventional background correction. Finally, the absorbed dose was calculated using the Medical Internal Radiation Dosimetry (MIRD) technique. The results of this study showed that the absorbed dose per unit of injected activity (rad/mCi) ± standard deviation for pelvis bone, bladder, and kidneys by Buijs method was 0.19 ± 0.05, 0.08 ± 0.01, and 0.03 ± 0.01 and by conventional method was 0.13 ± 0.04, 0.08 ± 0.01, and 0.024 ± 0.01, respectively. This showed that Buijs background correction method had a high accuracy compared to conventional method for the estimated absorbed dose of bone and kidneys whereas, for the bladder, its accuracy was low. PMID:27014610

  13. Comparison of diverse methods for the correction of atmospheric effects on LANDSAT and SKYLAB images. [radiometric correction in Brazil

    NASA Technical Reports Server (NTRS)

    Parada, N. D. J. (Principal Investigator); Camara, G.; Dias, L. A. V.; Mascarenhas, N. D. D.; Desouza, R. C. M.; Pereira, A. E. C.

    1982-01-01

    Earth's atmosphere reduces a sensors ability in currently discriminating targets. Using radiometric correction to reduce the atmospheric effects may improve considerably the performance of an automatic image interpreter. Several methods for radiometric correction from the open literature are compared leading to the development of an atmospheric correction system.

  14. Improvement of Aerosol Optical Depth Retrieval over Hong Kong from a Geostationary Meteorological Satellite Using Critical Reflectance with Background Optical Depth Correction

    NASA Technical Reports Server (NTRS)

    Kim, Mijin; Kim, Jhoon; Wong, Man Sing; Yoon, Jongmin; Lee, Jaehwa; Wu, Dong L.; Chan, P.W.; Nichol, Janet E.; Chung, Chu-Yong; Ou, Mi-Lim

    2014-01-01

    Despite continuous efforts to retrieve aerosol optical depth (AOD) using a conventional 5-channelmeteorological imager in geostationary orbit, the accuracy in urban areas has been poorer than other areas primarily due to complex urban surface properties and mixed aerosol types from different emission sources. The two largest error sources in aerosol retrieval have been aerosol type selection and surface reflectance. In selecting the aerosol type from a single visible channel, the season-dependent aerosol optical properties were adopted from longterm measurements of Aerosol Robotic Network (AERONET) sun-photometers. With the aerosol optical properties obtained fromthe AERONET inversion data, look-up tableswere calculated by using a radiative transfer code: the Second Simulation of the Satellite Signal in the Solar Spectrum (6S). Surface reflectance was estimated using the clear sky composite method, awidely used technique for geostationary retrievals. Over East Asia, the AOD retrieved from the Meteorological Imager showed good agreement, although the values were affected by cloud contamination errors. However, the conventional retrieval of the AOD over Hong Kong was largely underestimated due to the lack of information on the aerosol type and surface properties. To detect spatial and temporal variation of aerosol type over the area, the critical reflectance method, a technique to retrieve single scattering albedo (SSA), was applied. Additionally, the background aerosol effect was corrected to improve the accuracy of the surface reflectance over Hong Kong. The AOD retrieved froma modified algorithmwas compared to the collocated data measured by AERONET in Hong Kong. The comparison showed that the new aerosol type selection using the critical reflectance and the corrected surface reflectance significantly improved the accuracy of AODs in Hong Kong areas,with a correlation coefficient increase from0.65 to 0.76 and a regression line change from tMI [basic algorithm] = 0

  15. [Correction Multiplicative Effects in Raman Spectra through Vector Angle Transformation].

    PubMed

    Yao, Zhi-xiang; Sun, Zeng-qiang; Su, Hui; Yuan, Hong-fu

    2016-02-01

    The linear relationship between the Raman spectral intensity and the analyte amount is frequently disrupted for a variety of complex reasons, which include these variations in laser source, focusing effect, sample scattering and refracting, so that causes poor quantitative results. As a whole, these disturbing effects can be divided to be additive and multiplicative, and the multiplicative effects are generally more difficult to be eliminated. A spectrum is a series data, also can be treated as a vector. In principle, unstable motions in spectrum intensity/amplitude corresponding to the module shifts for a vector, doesn't impact the vector direction which is the essence of the vector, so it is reasonable to rewrite the data form on module to on space angle for the same measurement. This thesis employed a data transformation to eliminate the multiplicative effects within spectra, i. e. , the spectrum signal on its amplitude has been transformed to be on the vector angles. The first step of the transformation is the selection of a stand vector which is near to the analyte and almost orthogonal to the background within the sample space; and the next step is to define a moving window, then to find out the angle between the sample vector (i. e. the transformed spectrum) and the stand vector within the window; while the window is moved along the spectrum data series, the transformation for vector angle (VA) series has been finished. The thesis has proved that an approximate linear quantitative relationship has been remained in the VA series. Multivariate calibration need full rank matrix which is combined by spectrum from variety samples, and variety VA series also can combine a full rank VA matrix, so the approximate linear VA matrix still perfectly meeting the demand for multivariate calibration. A mixed system consisted by methanol-ethanol-isopropanol has been employed to verify the eliminations to the multiplicative effects. These measuring values of the system are

  16. The Effect of Background Music and Background Noise on the Task Performance of Introverts and Extraverts

    ERIC Educational Resources Information Center

    Cassidy, Gianna; MacDonald, Raymond A. R.

    2007-01-01

    The study investigated the effects of music with high arousal potential and negative affect (HA), music with low arousal potential and positive affect (LA), and everyday noise, on the cognitive task performance of introverts and extraverts. Forty participants completed five cognitive tasks: immediate recall, free recall, numerical and delayed…

  17. Effects of Streptococcus pneumoniae Strain Background on Complement Resistance

    PubMed Central

    Hyams, Catherine; Opel, Sophia; Hanage, William; Yuste, Jose; Bax, Katie; Henriques-Normark, Birgitta; Spratt, Brian G.; Brown, Jeremy S.

    2011-01-01

    Background Immunity to infections caused by Streptococcus pneumoniae is dependent on complement. There are wide variations in sensitivity to complement between S. pneumoniae strains that could affect their ability to cause invasive infections. Although capsular serotype is one important factor causing differences in complement resistance between strains, there is also considerable other genetic variation between S. pneumoniae strains that may affect complement-mediated immunity. We have therefore investigated whether genetically distinct S. pneumoniae strains with the same capsular serotype vary in their sensitivity to complement mediated immunity. Methodology and Principal Findings C3b/iC3b deposition and neutrophil association were measured using flow cytometry assays for S. pneumoniae strains with different genetic backgrounds for each of eight capsular serotypes. For some capsular serotypes there was marked variation in C3b/iC3b deposition between different strains that was independent of capsule thickness and correlated closely to susceptibility to neutrophil association. C3b/iC3b deposition results also correlated weakly with the degree of IgG binding to each strain. However, the binding of C1q (the first component of the classical pathway) correlated more closely with C3b/iC3b deposition, and large differences remained in complement sensitivity between strains with the same capsular serotype in sera in which IgG had been cleaved with IdeS. Conclusions These data demonstrate that bacterial factors independent of the capsule and recognition by IgG have strong effects on the susceptibility of S. pneumoniae to complement, and could therefore potentially account for some of the differences in virulence between strains. PMID:22022358

  18. Mapping Quantitative Trait Loci by Controlling Polygenic Background Effects

    PubMed Central

    Xu, Shizhong

    2013-01-01

    A new mixed-model method was developed for mapping quantitative trait loci (QTL) by incorporating multiple polygenic covariance structures. First, we used genome-wide markers to calculate six different kinship matrices. We then partitioned the total genetic variance into six variance components, one corresponding to each kinship matrix, including the additive, dominance, additive × additive, dominance × dominance, additive × dominance, and dominance × additive variances. The six different kinship matrices along with the six estimated polygenic variances were used to control the genetic background of a QTL mapping model. Simulation studies showed that incorporating epistatic polygenic covariance structure can improve QTL mapping resolution. The method was applied to yield component traits of rice. We analyzed four traits (yield, tiller number, grain number, and grain weight) using 278 immortal F2 crosses (crosses between recombinant inbred lines) and 1619 markers. We found that the relative importance of each type of genetic variance varies across different traits. The total genetic variance of yield is contributed by additive × additive (18%), dominance × dominance (14%), additive × dominance (48%), and dominance × additive (15%) variances. Tiller number is contributed by additive (17%), additive × additive (22%), and dominance × additive (43%) variances. Grain number is mainly contributed by additive (42%), additive × additive (19%), and additive × dominance (31%) variances. Grain weight is almost exclusively contributed by the additive (73%) variance plus a small contribution from the additive × additive (10%) variance. Using the estimated genetic variance components to capture the polygenic covariance structure, we detected 39 effects for yield, 39 effects for tiller number, 24 for grain number, and 15 for grain weight. The new method can be directly applied to polygenic-effect-adjusted genome-wide association studies (GWAS) in human and other

  19. Effects of Gravitational Correction on Neutron Stars with Antikaon Condensation

    NASA Astrophysics Data System (ADS)

    Ding, Wen-Bo; Hou, Jia-Wei; Qi, Zhan-Qiang; E, Shan-Shan; Bao, Tmurbagan; Liu, Guang-Zhou; Yu, Zi; Zhao, En-Guang

    2016-06-01

    Effects of gravitational correction through the introduction of U bosons on neutron stars with antikaon condensation are studied in the relativistic mean held theory. How the global properties of neutron stars, redshift and the momentum of inertia are modified by gravitational correction and antikaon condensation are discussed here. Results show that antikaon condensation can occur at the core of pulsar PSR J1614-2230. Gravitational correction and antikaon condensation influence each other, and when coupling constant of U bosons and baryons becomes very high, effects of antikaon condensation almost vanish. Moreover, both the redshift and the momentum of inertia of neutron stars are sensitive to the constant of U bosons. Combining with observation data, we can provide a further constraint on coupling constant of U bosons. Supported by National Natural Science Foundation of China under Grant Nos. 11265009, 11271055, and 11175077, and General Project of Liaoning Provincial Department of Education under Grant No. L2015005

  20. Systematic Effects in Polarizing Fourier Transform Spectrometers for Cosmic Microwave Background Observations

    NASA Astrophysics Data System (ADS)

    Nagler, Peter C.; Fixsen, Dale J.; Kogut, Alan; Tucker, Gregory S.

    2015-11-01

    The detection of the primordial B-mode polarization signal of the cosmic microwave background (CMB) would provide evidence for inflation. Yet as has become increasingly clear, the detection of a such a faint signal requires an instrument with both wide frequency coverage to reject foregrounds and excellent control over instrumental systematic effects. Using a polarizing Fourier transform spectrometer (FTS) for CMB observations meets both of these requirements. In this work, we present an analysis of instrumental systematic effects in polarizing FTSs, using the Primordial Inflation Explorer (PIXIE) as a worked example. We analytically solve for the most important systematic effects inherent to the FTS—emissive optical components, misaligned optical components, sampling and phase errors, and spin synchronous effects—and demonstrate that residual systematic error terms after corrections will all be at the sub-nK level, well below the predicted 100 nK B-mode signal.

  1. Effect of Background and Personality of Teachers on Teaching Teams.

    ERIC Educational Resources Information Center

    Cunningham, David F.

    Background and personality characteristics which are associated with successful team teaching were investigated for this study. Members of 31 secondary school teaching teams were rated by judges (who were principals, deans, and college consultants) individually and as teams on the bases of 10 background characteristics and eight personality…

  2. Priming effects under correct change detection and change blindness.

    PubMed

    Caudek, Corrado; Domini, Fulvio

    2013-03-01

    In three experiments, we investigated the priming effects induced by an image change on a successive animate/inanimate decision task. We studied both perceptual (Experiments 1 and 2) and conceptual (Experiment 3) priming effects, under correct change detection and change blindness (CB). Under correct change detection, we found larger positive priming effects on congruent trials for probes representing animate entities than for probes representing artifactual objects. Under CB, we found performance impairment relative to a "no-change" baseline condition. This inhibition effect induced by CB was modulated by the semantic congruency between the changed item and the probe in the case of probe images, but not for probe words. We discuss our results in the context of the literature on the negative priming effect. PMID:22964454

  3. Effect of Quantum Correction in the Bose-Hubbard Model

    SciTech Connect

    Matsumoto, Hideki; Takahashi, Kiyoshi; Ohashi, Yoji

    2006-09-07

    Effects of quantum correction in the Bose-Hubbard model at finite temperature are investigated for a homogeneous atomic Bose gas in an optical lattice near its superfluid-insulator transition. Starting from a strong coupling limit, higher order quantum corrections due to the hopping interaction is included in a local approximation (a dynamical mean field approximation) of the non-crossing approximation. When the upper or lower Hubbard band approaches zero energy, there appears a shallow band in the middle of the Hubbard gap due to a strong correlation in the system.

  4. High Precision Pulsar Timing: Effects of ISM Correction Schemes

    NASA Astrophysics Data System (ADS)

    Kunert, Willie; Verbiest, J. P. W.; Shannon, R.; Stinebring, D.

    2012-01-01

    Pulsar timing arrays are one of the leading methods in the search for gravitational waves (GWs). However a significant issue facing this method is the effect of the interstellar medium (ISM). There are multiple methodologies being used to correct for these effects but their efficacy has not been carefully studied. We conducted an initial study of biases induced by correcting for the interstellar medium. We simulated times of arrival (TOAs) with white noise and added ISM delays. We measure the ISM effects as is done with normal data, and created a model of these effects using polynomial fitting. This modeling method is most commonly used in the European Pulsar Timing Array. We then remove these measured ISM effects and compare final and initial TOAs. Ideally they should be the same; however, the differences between the 'corrected' TOAs and original TOAs reveal the weaknesses of this method. In preliminary results we concluded that the higher order polynomials do a better job, yet there is a limit as to how high an order one can use. We also found no significant systematic parameter bias induced by using this method. However, it is clear that certain parameters are more affected by this process of correction. The parameters most affected were the frequency and frequency derivative of the pulsar, but biases in these parameters are not important because the power due to them gets removed in the standard timing analysis. We are continuing this research by comparing and contrasting ISM correction schemes, as well as studying the actual behavior of the ISM in more detail. This research is supported by an NSF-PIRE and an NSF-AST grant.

  5. Ship Effect Neutron Measurements And Impacts On Low-Background Experiments

    SciTech Connect

    Aguayo Navarrete, Estanislao; Kouzes, Richard T.; Siciliano, Edward R.

    2013-10-01

    The primary particles entering the upper atmosphere as cosmic rays create showers in the atmosphere that include a broad spectrum of secondary neutrons, muons and protons. These cosmic-ray secondaries interact with materials at the surface of the Earth, yielding prompt backgrounds in radiation detection systems, as well as inducing long-lived activities through spallation events, dominated by the higher-energy neutron secondaries. For historical reasons, the multiple neutrons produced in spallation cascade events are referred to as “ship effect” neutrons. Quantifying the background from cosmic ray induced activities is important to low-background experiments, such as neutrino-less double beta decay. Since direct measurements of the effects of shielding on the cosmic-ray neutron spectrum are not available, Monte Carlo modeling is used to compute such effects. However, there are large uncertainties (orders of magnitude) in the possible cross-section libraries and the cosmic-ray neutron spectrum for the energy range needed in such calculations. The measurements reported here were initiated to validate results from Monte Carlo models through experimental measurements in order to provide some confidence in the model results. The results indicate that the models provide the correct trends of neutron production with increasing density, but there is substantial disagreement between the model and experimental results for the lower-density materials of Al, Fe and Cu.

  6. Suppression of Background Odor Effect in Odor Sensing System Using Olfactory Adaptation Model

    NASA Astrophysics Data System (ADS)

    Ohba, Tsuneaki; Yamanaka, Takao

    In this study, a new method for suppressing the background odor effect is proposed. Since odor sensors response to background odors in addition to a target odor, it is difficult to detect the target odor information. In the conventional odor sensing systems, the effect of the background odors are compensated by subtracting the response to the background odors (the baseline response). Although this simple subtraction method is effective for constant background odors, it fails in the compensation for time-varying background odors. The proposed method for the background suppression is effective even for the time-varying background odors.

  7. Correcting electrode impedance effects in broadband SIP measurements

    NASA Astrophysics Data System (ADS)

    Huisman, Johan Alexander; Zimmermann, Egon; Esser, Odilia; Haegel, Franz-Hubert; Vereecken, Harry

    2016-04-01

    Broadband spectral induced polarization (SIP) measurements of the complex electrical resistivity can be affected by the contact impedance of the potential electrodes above 100 Hz. In this study, we present a correction procedure to remove electrode impedance effects from SIP measurements. The first step in this correction procedure is to estimate the electrode impedance using a measurement with reversed current and potential electrodes. In a second step, this estimated electrode impedance is used to correct SIP measurements based on a simplified electrical model of the SIP measurement system. We evaluated this new correction procedure using SIP measurements on water because of the well-defined dielectric properties. It was found that the difference between the corrected and expected phase of the complex electrical resistivity of water was below 0.1 mrad at 1 kHz for a wide range of electrode impedances. In addition, SIP measurements on a saturated unconsolidated sediment sample with two types of potential electrodes showed that the measured phase of the electrical resistivity was very similar (difference <0.2 mrad) up to a frequency of 10 kHz after the effect of the different electrode impedances was removed. Finally, SIP measurements on variably saturated unconsolidated sand were made. Here, the plausibility of the phase of the electrical resistivity was improved for frequencies up to 1 kHz, but errors remained for higher frequencies due to the approximate nature of the electrode impedance estimates and some remaining unknown parasitic capacitances that led to current leakage. It was concluded that the proposed correction procedure for SIP measurements improved the accuracy of the phase measurements by an order of magnitude in the kHz frequency range. Further improvement of this accuracy requires a method to accurately estimate parasitic capacitances in situ.

  8. Correction of Rayleigh Scattering Effects in Cloud Optical Thickness Retrievals

    NASA Technical Reports Server (NTRS)

    Wang, Meng-Hua; King, Michael D.

    1997-01-01

    We present results that demonstrate the effects of Rayleigh scattering on the 9 retrieval of cloud optical thickness at a visible wavelength (0.66 Am). The sensor-measured radiance at a visible wavelength (0.66 Am) is usually used to infer remotely the cloud optical thickness from aircraft or satellite instruments. For example, we find that without removing Rayleigh scattering effects, errors in the retrieved cloud optical thickness for a thin water cloud layer (T = 2.0) range from 15 to 60%, depending on solar zenith angle and viewing geometry. For an optically thick cloud (T = 10), on the other hand, errors can range from 10 to 60% for large solar zenith angles (0-60 deg) because of enhanced Rayleigh scattering. It is therefore particularly important to correct for Rayleigh scattering contributions to the reflected signal from a cloud layer both (1) for the case of thin clouds and (2) for large solar zenith angles and all clouds. On the basis of the single scattering approximation, we propose an iterative method for effectively removing Rayleigh scattering contributions from the measured radiance signal in cloud optical thickness retrievals. The proposed correction algorithm works very well and can easily be incorporated into any cloud retrieval algorithm. The Rayleigh correction method is applicable to cloud at any pressure, providing that the cloud top pressure is known to within +/- 100 bPa. With the Rayleigh correction the errors in retrieved cloud optical thickness are usually reduced to within 3%. In cases of both thin cloud layers and thick ,clouds with large solar zenith angles, the errors are usually reduced by a factor of about 2 to over 10. The Rayleigh correction algorithm has been tested with simulations for realistic cloud optical and microphysical properties with different solar and viewing geometries. We apply the Rayleigh correction algorithm to the cloud optical thickness retrievals from experimental data obtained during the Atlantic

  9. Electroweak corrections to high energy processes using effective field theory

    SciTech Connect

    Chiu Juiyu; Golf, Frank; Kelley, Randall; Manohar, Aneesh V.

    2008-03-01

    Electroweak Sudakov logarithms at high energy, of the form ({alpha}/sin{sup 2}{theta}{sub W}){sup n}log{sup m}s/M{sub Z,W}{sup 2}, are summed using effective theory methods. The corrections are computed to processes involving two external particles in the standard model. The results include nonzero particle masses, such as the t-quark mass, electroweak mixing effects which lead to unequal W and Z masses, and radiative Higgs corrections proportional to the Yukawa couplings. We show that the matching at the scale M{sub W,Z} has a term at most linear in logs/{mu}{sup 2} to all orders. The effective theory formalism is compared with, and extends, previous work based on infrared evolution equations.

  10. Effect of backgrounding system on beef calf performance

    Technology Transfer Automated Retrieval System (TEKTRAN)

    In the Midwest, opportunity to integrate cattle production into cropping systems abounds. Two winter forage sources are corn residues and double cropped cool season annuals planted after corn silage harvest. The objective of this study was to evaluate backgrounding spring born calves using these fee...

  11. Aerosol effects and corrections in the Halogen Occultation Experiment

    NASA Technical Reports Server (NTRS)

    Hervig, Mark E.; Russell, James M., III; Gordley, Larry L.; Daniels, John; Drayson, S. Roland; Park, Jae H.

    1995-01-01

    The eruptions of Mt. Pinatubo in June 1991 increased stratospheric aerosol loading by a factor of 30, affecting chemistry, radiative transfer, and remote measurements of the stratosphere. The Halogen Occultation Experiment (HALOE) instrument on board Upper Atmosphere Research Satellite (UARS) makes measurements globally for inferring profiles of NO2, H2O, O3, HF, HCl, CH4, NO, and temperature in addition to aerosol extinction at five wavelengths. Understanding and removing the aerosol extinction is essential for obtaining accurate retrievals from the radiometer channels of NO2, H2O and O3 in the lower stratosphere since these measurements are severely affected by contaminant aerosol absorption. If ignored, aerosol absorption in the radiometer measurements is interpreted as additional absorption by the target gas, resulting in anomalously large mixing ratios. To correct the radiometer measurements for aerosol effects, a retrieved aerosol extinction profile is extrapolated to the radiometer wavelengths and then included as continuum attenuation. The sensitivity of the extrapolation to size distribution and composition is small for certain wavelength combinations, reducing the correction uncertainty. The aerosol corrections extend the usable range of profiles retrieved from the radiometer channels to the tropopause with results that agree well with correlative measurements. In situations of heavy aerosol loading, errors due to aerosol in the retrieved mixing ratios are reduced to values of about 15, 25, and 60% in H2O, O3, and NO2, respectively, levels that are much less than the correction magnitude.

  12. Effective radiation attenuation calibration for breast density: compression thickness influences and correction

    PubMed Central

    2010-01-01

    Background Calibrating mammograms to produce a standardized breast density measurement for breast cancer risk analysis requires an accurate spatial measure of the compressed breast thickness. Thickness inaccuracies due to the nominal system readout value and compression paddle orientation induce unacceptable errors in the calibration. Method A thickness correction was developed and evaluated using a fully specified two-component surrogate breast model. A previously developed calibration approach based on effective radiation attenuation coefficient measurements was used in the analysis. Water and oil were used to construct phantoms to replicate the deformable properties of the breast. Phantoms consisting of measured proportions of water and oil were used to estimate calibration errors without correction, evaluate the thickness correction, and investigate the reproducibility of the various calibration representations under compression thickness variations. Results The average thickness uncertainty due to compression paddle warp was characterized to within 0.5 mm. The relative calibration error was reduced to 7% from 48-68% with the correction. The normalized effective radiation attenuation coefficient (planar) representation was reproducible under intra-sample compression thickness variations compared with calibrated volume measures. Conclusion Incorporating this thickness correction into the rigid breast tissue equivalent calibration method should improve the calibration accuracy of mammograms for risk assessments using the reproducible planar calibration measure. PMID:21080916

  13. False fame prevented: avoiding fluency effects without judgmental correction.

    PubMed

    Topolinski, Sascha; Strack, Fritz

    2010-05-01

    Three studies show a way to prevent fluency effects independently of judgmental correction strategies by identifying and procedurally blocking the sources of fluency variations, which are assumed to be embodied in nature. For verbal stimuli, covert pronunciations are assumed to be the crucial source of fluency gains. As a consequence, blocking such pronunciation simulations through a secondary oral motor task decreased the false-fame effect for repeatedly presented names of actors (Experiment 1) as well as prevented increases in trust due to repetition for brand names and names of shares in the stock market (Experiment 2). Extending this evidence beyond repeated exposure, we demonstrated that blocking oral motor simulations also prevented fluency effects of word pronunciation on judgments of hazardousness (Experiment 3). Concerning the realm of judgment correction, this procedural blocking of (biasing) associative processes is a decontamination method not considered before in the literature, because it is independent of exposure control, mood, motivation, and post hoc correction strategies. The present results also have implications for applied issues, such as advertising and investment decisions. PMID:20438220

  14. The effect of a scanning flat fold mirror on a cosmic microwave background B-mode experiment.

    PubMed

    Grainger, William F; North, Chris E; Ade, Peter A R

    2011-06-01

    We investigate the possibility of using a flat-fold beam steering mirror for a cosmic microwave background B-mode experiment. An aluminium flat-fold mirror is found to add ∼0.075% polarization, which varies in a scan synchronous way. Time-domain simulations of a realistic scanning pattern are performed, and the effect on the power-spectrum illustrated, and a possible method of correction applied. PMID:21721713

  15. Background shifts affect explanatory style: how a pragmatic theory of explanation accounts for background effects in the generation of explanations.

    PubMed

    Chin-Parker, Seth; Bradner, Alexandra

    2010-08-01

    Cognitive scientists are interested in explanation because it provides a window into the cognition that underlies one's understanding of the world. We argue that the study of explanation has tended to focus on what makes an explanation "bona fide" as opposed to the processes involved in how the explanation is generated. In the current study, we asked participants to respond to the request for an explanation within a novel domain after we manipulated their initial exposure to the domain, and thus the background of the request. In two experiments, we found evidence that the background shaped participants' interpretations of the prompt for the explanation and that this, in turn, influenced whether they used a causal or functional style of explanation when responding to the prompt. We also asked participants to evaluate a number of explanations and found that the manipulation of the background did not have the same effect on the evaluative tasks. Our data support a pragmatic approach (e.g. The scientific image. Oxford University Press, Oxford, 1980) to the study of explanation generation, a philosophical approach which argues that the background influences the interpretation of the question, the development of a relevance relation which connects the question and explanation, and the identification of some set of candidate answers. We also suggest there is an important difference between the process of generating an explanation and evaluating an explanation, a difference that has escaped the attention of cognitive scientists thus far. PMID:19859755

  16. Comparative Evaluation of Enalapril and Losartan in Pharmacological Correction of Experimental Osteoporosis and Fractures of Its Background

    PubMed Central

    Rajkumar, D. S. R.; Faitelson, A. V.; Gudyrev, O. S.; Dubrovin, G. M.; Pokrovski, M. V.; Ivanov, A. V.

    2013-01-01

    In the experiment on the white Wistar female rats (222 animals), the osteoprotective effect of enalapril and losartan was studied on experimental models of osteoporosis and osteoporotic fractures. It was revealed that in rats after ovariectomy, the endothelial dysfunction of microcirculation vessels of osteal tissue develops, resulting in occurrence of osteoporosis and delay of consolidation of experimental fractures. Enalapril and losartan prevented the reduction of microcirculation in bone, which was reflected in slowing the thinning of bone trabeculae and in preventing the occurrence of these microfractures, as well as increasing quality of experimental fractures healing. PMID:23401845

  17. Comparative evaluation of enalapril and losartan in pharmacological correction of experimental osteoporosis and fractures of its background.

    PubMed

    Rajkumar, D S R; Faitelson, A V; Gudyrev, O S; Dubrovin, G M; Pokrovski, M V; Ivanov, A V

    2013-01-01

    In the experiment on the white Wistar female rats (222 animals), the osteoprotective effect of enalapril and losartan was studied on experimental models of osteoporosis and osteoporotic fractures. It was revealed that in rats after ovariectomy, the endothelial dysfunction of microcirculation vessels of osteal tissue develops, resulting in occurrence of osteoporosis and delay of consolidation of experimental fractures. Enalapril and losartan prevented the reduction of microcirculation in bone, which was reflected in slowing the thinning of bone trabeculae and in preventing the occurrence of these microfractures, as well as increasing quality of experimental fractures healing. PMID:23401845

  18. The Unreasonable Effectiveness of Exponentially Suppressed Corrections in Preserving Information

    NASA Astrophysics Data System (ADS)

    Papadodimas, Kyriakos; Raju, Suvrat

    2013-11-01

    We point out that nonperturbative effects in quantum gravity are sufficient to reconcile the process of black hole evaporation with quantum mechanics. In ordinary processes, these corrections are unimportant because they are suppressed by e-S. However, they gain relevance in information-theoretic considerations because their small size is offset by the corresponding largeness of the Hilbert space. In particular, we show how such corrections can cause the von Neumann entropy of the emitted Hawking quanta to decrease after the Page time, without modifying the thermal nature of each emitted quantum. Second, we show that exponentially suppressed commutators between operators inside and outside the black hole are sufficient to resolve paradoxes associated with the strong subadditivity of entropy without any dramatic modifications of the geometry near the horizon.

  19. Improved analysis for matrix effect correction in LLW neutronic assay

    NASA Astrophysics Data System (ADS)

    Raoux, A.-C.; Loridon, J.; Mariani, A.; Passard, C.

    2008-11-01

    The matrix effect correction for the differential die-away (DDA) measurement is an improvement in the fissile material content determination. In low-level radioactive waste (LLW) packages examination, the most widely used methods are based on neutron flux monitoring with 3He tubes, associated to a "matrix interrogation source" (MIS) originally developed for passive neutron measurement and which determine an experimental detection efficiency. This paper describes two new approaches developed with the goal of increasing the accuracy of the matrix effect correction and reducing the measurement time, which is a major objective in the non destructive assay (NDA) of large number of waste packages. The first method is based on an active prompt neutron coincidence measurement using a new generation list mode data card, which is an alternative to the MIS. Monte Carlo simulations have been performed to determine the correction function parameters. An experimental agreement within 20% is obtained with a fissile sample localized at the centre of different matrices provided that the positioning effect remains negligible. Homogeneous distributions of the fissile material have also been simulated and lead to a deviation less than 15% for most of the cases. The second method exploits the effect of matrices on the total active signal. A simulated annealing algorithm, using a reference data base of multi-channel scaling (MCS) spectra, is performed to fit the raw signal. The construction of the MCS library involves a learning phase to define and acquire the DDA signals as representative as possible of the real measurement conditions. Most of the cases are within a 4% agreement interval with the expected experimental value.

  20. Correction on the effect of numerical aperture in optical scatterometry

    NASA Astrophysics Data System (ADS)

    Li, Weiqi; Liu, Shiyuan; Zhang, Chuanwei; Chen, Xiuguo; Gu, Honggang

    2013-10-01

    Optical scatterometry, also referred to as optical critical dimension (OCD) metrology, has been introduced for critical dimension (CD) monitoring and overlay metrology with great success in recent years. Forward modeling to calculate the optical signature from the measured diffractive structure is one of the most important issues in OCD metrology. To simplify the forward modeling approach, such as rigorous coupled-wave analysis (RCWA), the incidence and azimuthal angles are usually assumed to be constant. However, since some focusing elements, such as focusing lens or parabolic mirrors with finite numerical aperture (NA), are always used to gain a sufficient small spot size onto the sample, this assumption is not true in the whole exit pupil of the focusing elements, leading to a modeling error in forward modeling, and finally leading to a fitting error in OCD metrology. In this paper, we propose a correction method with consideration of the effect of NA to decrease the modeling error in the forward modeling. The correction method is an average integral method based on Gaussian quadrature in two dimensions inside a circle, and is performed on forward modeling with varied incidence and azimuthal angles over the exit pupil. Experiments performed on silicon gratings with a Mueller matrix polarimeter have demonstrated that the proposed correction method achieves a higher accuracy in OCD metrology.

  1. Effects of age, gender and educational background on strength of motivation for medical school.

    PubMed

    Kusurkar, Rashmi; Kruitwagen, Cas; ten Cate, Olle; Croiset, Gerda

    2010-08-01

    The aim of this study was to determine the effects of selection, educational background, age and gender on strength of motivation to attend and pursue medical school. Graduate entry (GE) medical students (having Bachelor's degree in Life Sciences or related field) and Non-Graduate Entry (NGE) medical students (having only completed high school), were asked to fill out the Strength of Motivation for Medical School (SMMS) questionnaire at the start of medical school. The questionnaire measures the willingness of the medical students to pursue medical education even in the face of difficulty and sacrifice. GE students (59.64 ± 7.30) had higher strength of motivation as compared to NGE students (55.26 ± 8.33), so did females (57.05 ± 8.28) as compared to males (54.30 ± 8.08). 7.9% of the variance in the SMMS scores could be explained with the help of a linear regression model with age, gender and educational background/selection as predictor variables. Age was the single largest predictor. Maturity, taking developmental differences between sexes into account, was used as a predictor to correct for differences in the maturation of males and females. Still, the gender differences prevailed, though they were reduced. Pre-entrance educational background and selection also predicted the strength of motivation, but the effect of the two was confounded. Strength of motivation appears to be a dynamic entity, changing primarily with age and maturity and to a small extent with gender and experience. PMID:19774476

  2. Atmospheric effect on spectral signature - Measurements and corrections

    NASA Technical Reports Server (NTRS)

    Kaufman, Yoram J.

    1988-01-01

    Measurements of the atmospheric effect on the spectral signature of surface cover were conducted during hazy conditions over the Chesapeake Bay and its eastern shore. In the experiment the upward radiance was measured by an airborne scanning radiometer in nine spectral bands between 465 and 773 nm, above and below the haze layer. Simultaneous measurements of the aerosol optical thickness and its vertical distribution were conducted. The results of the measurements are used to study the spectral dependence of the atmospheric effect on remote sensing of water bodies and vegetated fields (forest, corn field, and pasture), and to verify theoretical predictions. It is suggested that the radiances over dark areas (e.g., water in the near IR and forest in the visible) can be used to derive the aerosol optical thickness as is done over oceans with the CZCS satellite images. Combined with climatological information, the derived optical thickness can be used to perform corrections of the atmospheric effect. Examples of the derivation of the aerosol optical thickness and correction of the upward radiances are given.

  3. Terrain effects in the atmospheric gravity and geoid corrections

    NASA Astrophysics Data System (ADS)

    Sjoberg, Lars E.

    1993-07-01

    In view of the smallness of the atmospheric mass compared to the mass variations within the Earth, it is generally assumed in physical geodesy that terrain effects are negligible. Subsequently most models assume a spherical or ellipsoidal layering of the atmosphere. The removal and restoring of the atmosphere in solving the exterior boundary value problems thus correspond to gravity and geoid corrections of the order of 0.9 mGal and -0.7 cm, respectively. We demonstrate that the gravity terrain correction for the removal of the atmosphere is of the order of 50 microGal/km of elevation with a maximum close to 0.5 mGal at the top of Mount Everest. The corresponding effect on the geoid may reach several cm in mountainous regions. The total effect on geoid determination of removal and restoring the atmosphere may contribute significantly, in particular for long wavelengths. This is not the case for the quasi-geoid in mountainous regions.

  4. Corrections of surface fissure effect on apparent resistivity measurements

    NASA Astrophysics Data System (ADS)

    Gance, J.; Sailhac, P.; Malet, J.-P.

    2015-02-01

    Electrical resistivity tomography (ERT) is a useful tool to detect and track water flow paths in the subsoil. However, measurements are strongly affected by subsurface heterogeneities such as fissures of different sizes and genesis (shrinking-swelling, macropores and deformation). In this work, we focus on surface fissures characterized by dimensions lower than the interelectrode spacing and correct their effect on apparent resistivity pseudo-sections by incorporating fissure geometry in the topography. We show that fissures with depths greater than 0.10 times the interelectrode spacing for a dipole-dipole array and equal to 0.16 for the gradient array and the Wenner-Schlumberger arrays create significant anomalies (greater than 5 per cent) in the pseudo-section. Surface fissure widths and dip angles have little effect with respect to the fissure depths which can increase the apparent resistivity up to 200 per cent. The clogging of the fissures with water or soil material decreases the anomaly effect linearly with the percentage of filling. The correction of apparent resistivity values is possible for relatively simple fissure geometries and only requires a manual survey of the surface fissures. It allows to improve the quality of the inverted resistivity section by mitigating the inversion artefacts and therefore a better interpretation.

  5. Effects of Immediate Self-Correction, Delayed Self-Correction, and No Correction on the Acquisition and Maintenance of Multiplication Facts by a Fourth Grade Student with Learning Disabilities.

    ERIC Educational Resources Information Center

    Bennett, Kristine; Cavanaugh, Rodney A.

    1998-01-01

    A study compared the effects of immediate self-correction, delayed self-correction, and no correction on the acquisition and maintenance of multiplication facts by a fourth-grade student with learning disabilities. Results indicate that both correct response rate and accuracy were higher when self-corrections were immediate rather than delayed or…

  6. Effects of immediate self-correction, delayed self-correction, and no correction on the acquisition and maintenance of multiplication facts by a fourth-grade student with learning disabilities.

    PubMed Central

    Bennett, K; Cavanaugh, R A

    1998-01-01

    This study compared the effects of immediate self-correction, delayed self-correction, and no correction on the acquisition and maintenance of multiplication facts by a fourth-grade student with learning disabilities. Data from daily and maintenance tests indicated that both correct response rate and accuracy were higher when self-correction was immediate rather than delayed or absent. PMID:9652107

  7. Resist charging effect correction function qualification for photomasks production

    NASA Astrophysics Data System (ADS)

    Sidorkin, Vadim; Finken, Michael; Wandel, Timo; Nakayamada, Noriaki; Cantrell, G. R.

    2014-10-01

    We quantitatively evaluate Nuflare's latest resist charging effect correction (CEC) model for advanced photomask production using e-beam lithography. Functionality of this CEC model includes the simulation of static and timedependent charging effects together with an improved calibration method. CEC model calibration is performed by polynomial fitting of image placement distortions induced by various beam scattering effects on a special test design with writing density variations. CEC model parameters can be fine tuned for different photomask blank materials facilitating resist charging compensation maps for different product layers. Application of this CEC model into production yields a significant reduction in photomask image placement (IP), as well as improving photomask overlay between critical neighbouring layers. The correlations between IP improvement facilitated by this CEC model and single mask parameters are presented and discussed. The layer design specifics, resist and blank materials, coupled with their required exposure parameters are observed to be the major influences on CEC model performance.

  8. Effect of background plasma nonlinearities on dissipation processes in plasmas

    NASA Astrophysics Data System (ADS)

    Nekrasov, F. M.; Elfimov, A. G.; de Azevedo, C. A.; de Assis, A. S.

    1999-01-01

    The Coulomb collision effect on the bounce-resonance dissipation is considered for toroidal magnetized plasmas. The solution of the Vlasov equation with a simplified Fokker-Planck collision operator is presented. The parallel components of the dielectric tensor are obtained. A collisionless limit of wave dissipation is found.

  9. Self-corrected elaboration effects on incidental memory.

    PubMed

    Toyota, Hiroshi

    2004-10-01

    Subjects performed an orienting task involving 3 conditions followed by an unexpected free recall test. The conditions were designed to force 3 types of corrected elaborations: Generated Correction, Chosen Correction, and No Correction. In the Generated Correction condition the subjects were presented with a target word (e.g., Baby) and a bizarre sentence frame (e.g., "____drinks beer.") and asked to correct the target to a congruous word (e.g., Uncle) to make a common sentence. In the Chosen Correction condition, the subjects were presented with a target and its bizarre sentence frame and asked to choose one of the alternative congruous words (e.g., Uncle, Aunt) to make a common sentence. In the No Correction condition, the subjects were presented with a target and its bizarre sentence frame and asked to rate the congruity of each target to its sentence frame. Generated Correction led to a better performance than Chosen Correction and No Correction, but a difference between the last two correction types was not found. These results were interpreted as showing that, by generating correct information, self-corrected elaboration led to facilitation of incidental memory. PMID:15560341

  10. A simulation study of linear coupling effects and their correction in RHIC

    SciTech Connect

    Parzen, G.

    1993-01-01

    This paper describes a possible skew quadrupole correction system for linear coupling effects for the RHIC92 lattice. A simulation study has been done for this correction system. Results are given for the performance of the correction system and the required strength of the skew quadrupole corrections. The location of the correctors is discussed. For RHIC92, it appears possible to use the same 2 family correction system for all the likely choices of [beta]*. The simulation study gives results for the residual tune splitting that remains after correction with a 2 family correction system. It also gives results for the beta functions before and after correction.

  11. A simulation study of linear coupling effects and their correction in RHIC

    SciTech Connect

    Parzen, G.

    1993-06-01

    This paper describes a possible skew quadrupole correction system for linear coupling effects for the RHIC92 lattice. A simulation study has been done for this correction system. Results are given for the performance of the correction system and the required strength of the skew quadrupole corrections. The location of the correctors is discussed. For RHIC92, it appears possible to use the same 2 family correction system for all the likely choices of {beta}*. The simulation study gives results for the residual tune splitting that remains after correction with a 2 family correction system. It also gives results for the beta functions before and after correction.

  12. Effect of parallactic refraction correction on station height determination

    NASA Technical Reports Server (NTRS)

    Lerch, F. J.; Huston, H. A.

    1973-01-01

    The effect of omitting the parallactic refraction correction for satellite optical observations in the determination of station coordinates is analyzed for a large satellite data distribution. A significant error effect is seen in station heights. A geodetic satellite data distribution of 23 close earth satellites, containing 30,000 optical observations obtained by 13 principal Baker-Nunn camera sites, is employed. This distribution was used in a preliminary Goddard Earth Model (GEM 1) for the determination of the gravity field of the earth and geocentric tracking station locations. The parallactic refraction correction is modeled as an error on the above satellite data and a least squares adjustment for station locations is obtained for each of the 13 Baker-Nunn sites. Results show an average station height shift of +8 meters with a dispersion of plus or minus 0.7 meters for individual sites. Station latitude and longitude shifts amounted to less than a meter. Similar results are obtained from a theoretical method employing a probability distribution for the satellite optical observations.

  13. Pixel-based CTE Correction Of ACS/WFC: Effects On Signal To Noise Ratio

    NASA Astrophysics Data System (ADS)

    Avila, Roberto J.; Fruchter, A.; Anderson, J.; ACS Team

    2012-01-01

    The Advanced Camera for Surveys (ACS) team at STScI has tested a new pixel-based empirical correction (Anderson & Bedin, PASP, 122, 1035) software for CTE effects that occur due to the high radiation environment of space. Here we present a study of how this algorithm changes the characteristics of the signal to noise ratio and photometry of point sources. In order to eliminate unknown variables we use simulated images where we can control the noise and CTE characteristics. We explore a parameter space that includes background, object brightness, and position on the chip. Overall we find that while the signal in a source is largely recovered, the noise in the background is amplified. This effect is more noticeable in low background levels and in regions far from the readout amplifiers. Extra care must be taken when measuring the sky background because the use of some common measurement schemes can introduce systematic effects in the photometry. We also show how a simple noise mitigation routine helps in reducing these effects, although they are not completely eliminated.

  14. Determination of selenium in infant formula and enteral formula by dry ash graphite furnace atomic absorption spectrometry with deuterium background correction.

    PubMed

    Cook, K K

    1996-01-01

    A method was developed to determine selenium in infant formula using a graphite furnace equipped with deuterium background correction after dry ashing. The method circumvents the use of perchloric acid, 2,3-diaminonapthalene (DAN) and hydride generation without the use of Zeeman background correction. Twelve commercial infant and enteral formulas and corresponding spiked products (30-500 ng) were analyzed in triplicate for Se to evaluate this method. All test portions were digested on a hot plate after addition of magnesium nitrate-nitric acid. Following heating, digests were evaporated to dryness and placed in a 500 degrees C muffle furnace for 30 min to complete ashing. All Se was converted to Se+4 by dissolving the ash in HCl (5 + 1) and holding the solution for 20 min in a 60 degrees C water bath. Se+4 was subsequently reduced to Se(zero) with ascorbic acid and collected on a membrane filter. The membrane filters were digested in a small volume of nitric acid in a microwave oven. Following digestion, contents of the vessels were diluted and analyzed for Se by graphite furnace atomic absorption spectrometry. Selenium standards in starch or in unfortified formula containing trace levels of Se were carried through the entire process. The recovery range for Se was 85-127%, and analyzed reference materials fell within their certified range for Se. This method is as sensitive (detection limit 0.44 ng Se/g) as methods reported in the literature and may be applicable to other foods. PMID:8823924

  15. Effectiveness of false correction strategy on science reading comprehension

    NASA Astrophysics Data System (ADS)

    Ghent, Cynthia Anne

    False-correction reading strategy theoretically prompted college students to activate their prior knowledge when provided false statements linked to a portion of their biology textbook. This strategy is based in elaborative interrogation theory, which suggests that prompting readers to answer interrogatives about text students are reading increases their comprehension of that text. These interrogatives always asked "why" statements pulled from a text, one sentence in length, were "true." True statements in this study based on a text were converted by the experimenter into false statements, one sentence in length. Students were requested to rewrite each statement (n=12) on average every 200 words in a text as they were reading, converting each false statement into a true statement. These students outperformed other students requested to reread the same biology text twice (an established placebo-control strategy). These students, in turn, outperformed still other students reading an unrelated control text taken from the same textbook used only to establish a prior knowledge baseline for all students included in this study. Students participating in this study were enrolled students in an undergraduate introductory general biology course designed for non-majors. A three-group, posttest-only, randomized experimental control-group design was used to prevent pretest activation of students' prior knowledge thus increasing chances of producing evidence of false-correction effectiveness and to begin augmenting potential generalizability to science classrooms. Students' (n=357) general biology knowledge, verbal ability, and attempts to use the false correction strategy were collected and analyzed. Eight of the participants were interviewed by the researcher in a first attempt in this domain to collect data on participants' points of view about the strategy. The results of this study are not yet recommended for use in authentic school settings as further research is indicated.

  16. The Effect of Postural Correction and Subsequent Balloon Inflation in Deformity Correction of Acute Osteoporotic Vertebral Fractures

    PubMed Central

    Liu, Hai-Xiao; Xu, Cong; Shang, Ping; Shen, Yue

    2014-01-01

    Objective To determine deformity correction by postural correction and subsequent balloon inflation in acute vertebral compression fractures (OVCFs) and to examine the effect of bone mineral density on deformity correction. Methods A totol of 50 acute OVCFs received balloon kyphoplasty. Lateral radiographs were taken and analyzed at five different time points : 1) preoperative, 2) after placing the patient in prone hyperextended position, 3) after balloon inflation, 4) after deposition of the cement, and 5) postoperative. All fractures were analyzed for height restoration of anterior (Ha), middle (Hm) and posterior (Hp) vertebra as well as Cobb angle and Kyphotic angle. The bone mineral density (BMD) of lumbar spine was measured by dual-energy X-ray absorptiometry. According to the T-score, the patients were divided into two groups which were osteoporosis group and osteopenia group. Results Postoperative measurements of Ha, Hm and the Cobb angle demonstrated significant reduction of 4.62 mm, 3.66 mm and 5.34° compared with the preoperative measurements, respectively (each p<0.05). Postural correction significantly increased Ha by 5.51 mm, Hm by 4.35 mm and improved the Cobb angle by 8.32° (each p<0.05). Balloon inflation did not demonstrate a significant improvement of Ha, Hm or the Cobb angle compared with baseline prone hyperextended. Postural correction led to greater improvements of Ha, Hm and Cobb angle in osteoporosis group than osteopenia group (each p<0.05). Conclusion In acute OVCFs, the height restoration was mainly attributed to postural correction rather than deformity correction by balloon inflation. BMD affected deformity correction in the process of postural correction. PMID:25237429

  17. Oral Contraceptive Use and the ECG: Evidence of an Adverse QT Effect on Corrected QT Interval

    PubMed Central

    Sedlak, Tara; Shufelt, Chrisandra; Iribarren, Carlos; Lyon, Liisa L; Merz, C. Noel Bairey

    2013-01-01

    Background A prolonged corrected QT (QTc) interval is a marker for an increased risk of sudden cardiac death. We evaluated the relationship between oral contraceptive (OC) use, type of OC, and QTc interval. Methods We identified 410,782 ECGs performed at Northern California Kaiser Permanente on female patients between 15–53 years from January, 1995 to June, 2008. QT was corrected for heart rate using log-linear regression. OC generation (first, second and third) was classified by increasing progestin androgenic potency, while the fourth generation was classified as anti-androgenic. Results Among 410,782 women, 8.4% were on OC. In multivariate analysis after correction for comorbidities, there was an independent shortening effect of OCs overall (slope = −0.5ms; SE = 0.12, p<0.0002). Users of first and second generation progestins had a significantly shorter QTc than non-users (p<0.0001), while users of fourth generation had a significantly longer QTc than non-users (slope = 3.6ms, SE = 0.35, p<0.0001). Conclusion Overall, OC use has a shortening effect on the QTc. Shorter QTc is seen with first and second generation OC while fourth generation OC use has a lengthening effect on the QTc. Careful examination of adverse event rates in fourth generation OC users is needed. PMID:23879279

  18. Practical correction procedures for elastic electron scattering effects in ARXPS

    NASA Astrophysics Data System (ADS)

    Lassen, T. S.; Tougaard, S.; Jablonski, A.

    2001-06-01

    Angle-resolved XPS and AES (ARXPS and ARAES) are widely used for determination of the in-depth distribution of elements in the surface region of solids. It is well known that elastic electron scattering has a significant effect on the intensity as a function of emission angle and that this has a great influence on the determined overlayer thicknesses by this method. However the applied procedures for ARXPS and ARAES generally neglect this because no simple and practical procedure for correction has been available. However recently, new algorithms have been suggested. In this paper, we have studied the efficiency of these algorithms to correct for elastic scattering effects in the interpretation of ARXPS and ARAES. This is done by first calculating electron distributions by Monte Carlo simulations for well-defined overlayer/substrate systems and then to apply the different algorithms. We have found that an analytical formula based on a solution of the Boltzmann transport equation provides a good account for elastic scattering effects. However this procedure is computationally very slow and the underlying algorithm is complicated. Another much simpler algorithm, proposed by Nefedov and coworkers, was also tested. Three different ways of handling the scattering parameters within this model were tested and it was found that this algorithm also gives a good description for elastic scattering effects provided that it is slightly modified so that it takes into account the differences in the transport properties of the substrate and the overlayer. This procedure is fairly simple and is described in detail. The model gives a much more accurate description compared to the traditional straight-line approximation (SLA). However it is also found that when attenuation lengths instead of inelastic mean free paths are used in the simple SLA formalism, the effects of elastic scattering are also reasonably well accounted for. Specifically, from a systematic study of several

  19. Cosmic Microwave Background Fluctuations from the Kinetic Sunyaev-Zeldovich Effect as a Cosmological Probe

    NASA Astrophysics Data System (ADS)

    Park, Hyunbae; Shapiro, P.; Komatsu, E.

    2012-01-01

    We present a calculation of the kinetic Sunyaev-Zel'dovich (kSZ) effect on of the Comic Microwave Background fluctuation. We focus on the scale at the multipole moment of l = 3000 10000 that is currently being probed by the South Pole Telescope (SPT) and the Atacama Cosmology Telescope. For the post-reionization contribution of the total signal, we use the 3rd order perturbation theory (3PT) to model non-linearity of post-reionization epoch. We evaluate a non-linear expression for momentum powerspectrum in Ma and Fry (2002) with the 3PT density and velocity powerspectrum. And, we use the 3PT momentum powerspectrum to calculate the kSZ signal. We show that the 3PT is a reasonable approximation by comparing our result with previous work by Zhang, Pen and Trac (2004). For reionization contribution, we use our N-body radiative transfer simulations to take patchiness of ionization of intergalactic medium in reionization epoch into account. Using ionized fraction field in the simulation, we calculate the momentum field of the ionized gas. And, we correct for the missing power in finite size boxes of simulations. Finally, we show the kSZ calculation for different simulations with reionization scenarios. With contributions from each epoch, we predict total kSZ signal for different reionization history and put constraint on reionization scenario using an upper bound of the signal from recent SPT measurement.

  20. An effective method on ship target detection in remote sensing image of complex background

    NASA Astrophysics Data System (ADS)

    Zuo, Zhengrong; Kuang, Xiaoqin

    2011-11-01

    This paper presents a method for ship target detecting in complex background. It aims at solving two difficulties in detection. The first one is that the ships docking in-shore cannot be segmented because of its gray level similarity to land, and the second is that the ships linked side by side cannot be easily located as separate correct target. The first one is solved by extracting water region firstly by measure of harbor-template matching. In order to reduce the impact of angle difference which leads to error, we update the template by the corresponding angle calculated recur to line feature. Then matching fine with the updated template to extract water region wholly in which the segment is effective. For the second difficulty, the smallest minimum bounding rectangle (SMBR) of the segmented areas are obtained by contour tracing, and the areas are projected to the two different directions of its SMBR, then the projection curves are acquired. If the ships are linking together, the peak-valley-peak pattern will exist in the projection curve and the valley-point indicates the ships' connection position. Then the ships can be separated by cutting the area at connection position along the projection direction. The experiment results verify the efficiency and accuracy of our method.

  1. Inhibition of calcium oxalate monohydrate growth by citrate and the effect of the background electrolyte

    NASA Astrophysics Data System (ADS)

    Weaver, Matthew L.; Qiu, S. Roger; Hoyer, John R.; Casey, William H.; Nancollas, George H.; De Yoreo, James J.

    2007-08-01

    Pathological mineralization is a common phenomenon in broad range of plants and animals. In humans, kidney stone formation is a well-known example that afflicts approximately 10% of the population. Of the various calcium salt phases that comprise human kidney stones, the primary component is calcium oxalate monohydrate (COM). Citrate, a naturally occurring molecule in the urinary system and a common therapeutic agent for treating stone disease, is a known inhibitor of COM. Understanding the physical mechanisms of citrate inhibition requires quantification of the effects of both background electrolytes and citrate on COM step kinetics. Here we report the results of an in situ AFM study of these effects, in which we measure the effect of the electrolytes LiCl, NaCl, KCl, RbCl, and CsCl, and the dependence of step speed on citrate concentration for a range of COM supersaturations. We find that varying the background electrolyte results in significant differences in the measured step speeds and in step morphology, with KCl clearly producing the smallest impact and NaCl the largest. The kinetic coefficient for the former is nearly three times larger than for the latter, while the steps change from smooth to highly serrated when KCl is changed to NaCl. The results on the dependence of step speed on citrate concentration show that citrate produces a dead zone whose width increases with citrate concentration as well as a continual reduction in kinetic coefficient with increasing citrate level. We relate these results to a molecular-scale view of inhibition that invokes a combination of kink blocking and step pinning. Furthermore, we demonstrate that the classic step-pinning model of Cabrera and Vermilyea (C-V model) does an excellent job of predicting the effect of citrate on COM step kinetics provided the model is reformulated to more realistically account for impurity adsorption, include an expression for the Gibbs-Thomson effect that is correct for all supersaturations

  2. Corrections for 17O interference, effects on Δ47 determination

    NASA Astrophysics Data System (ADS)

    Olack, G.; He, B.; Colman, A. S.

    2013-12-01

    The measurements of 13C on CO2 samples are routinely corrected for 17O contribution to the m/z 45 signal (Craig, 1957; Santrock, et al., 1985). The 17O abundance affects the Δ47 calculation, and the amount of 17O present is routinely determined using the relationship between 18O and 17O presented in IAEA TECDOC 825 (Dennis, et al., 2011; Huntington, et al., 2009; Gonfiantini, et al., 1995). In 2010, the IAEA released new recommendations for 17O determinations to be used for 13C corrections (Brand, et al., 2010). We compare the effect of using different ways to determine 17O interference, as well as using the currently accepted N(13C)/N(12C) value for VPDB (Brand, et al., 2010), on heated gas lines, model data, and on CO2 gases made to have similar δ47 and Δ47, but with highly contrasting δ18O and δ13C values. The 2010 IAEA recommendations give a better fit for heated gas data than the TECDOC 825 recommendations. Comparing differences in the data points relative to their respective fitted lines, we see differences on the order of 5 to 10 ppm in Δ47. That corresponds to a systematic error of 2 °C in the temperature estimate (room temperature range), and one that varies with δ13C and δ18O, but not necessarily with δ47. The preliminary work on equilibrated CO2 gases having similar δ47, but very different δ13C and δ18O, showed large (ca. 70 ppm) differences in Δ47 when using the (standard) TECDOC 825 recommendations. The Δ47 values were much closer when the 2010 IUPAC recommendations were used. This also serves as a test of the updated factors for 17O determination, as well as the overall robustness of the Δ47 measurement.

  3. Sun angle, view angle, and background effects on spectral response of simulated balsam fir canopies

    NASA Technical Reports Server (NTRS)

    Ranson, K. J.; Daughtry, C. S. T.; Biehl, L. L.

    1986-01-01

    An experiment is described that examines the effects of solar zenith angle and background reflectance on the composite scene reflectance of small balsam fir (Abies balsamea (L.) Mill.) arranged in different densities. In this study, the shape, density, and, consequently, the needle area index and phytomass of the canopies, as well as the background reflectance, were controlled. The effects of sun angle, view angle, and background reflectance on the multispectral response of small balsam fir trees were significant. Regression models relating spectral vegetation indices (i.e., normalized difference (ND) and greenness (GR) to phytomass) showed very poor relationships for balsam fir canopies with a grass background. However, strong linear relationships were found for ND and GR with phytomass for a background that simulated the reflectance of snow. Changing solar zenith angle significantly affected the models relating ND to phytomass for the snow background, but was not significant in the model relating GR to phytomass for the snow background

  4. The Effect of Clustering on Estimations of the UV Ionizing Background from the Proximity Effect

    NASA Astrophysics Data System (ADS)

    Pascarelle, S. M.; Lanzetta, K. M.; Chen, H. W.

    1999-09-01

    There have been several determinations of the ionizing background using the proximity effect observed in the distibution of Lyman-alpha absorption lines in the spectra of QSOs at high redshift. It is usually assumed that the distribution of lines should be the same at very small impact parameters to the QSO as it is at large impact parameters, and any decrease in line density at small impact parameters is due to ionizing radiation from the QSO. However, if these Lyman-alpha absorption lines arise in galaxies (Lanzetta et al. 1995, Chen et al. 1998), then the strength of the proximity effect may have been underestimated in previous work, since galaxies are known to cluster around QSOs. Therefore, the UV background estimations have likely been overestimated by the same factor.

  5. Geophone-seabed coupling effect and its correction

    NASA Astrophysics Data System (ADS)

    Zhang, Bao-Qing; Zhou, Hui; Li, Guo-Fa; Guo, Jian-Qing

    2016-03-01

    By summing geophone and hydrophone data with opposite polarity responses to water layer reverberation, the ocean bottom cable dual-sensor acquisition technique can effectively eliminate reverberation, broaden the frequency bandwidth, and improve both the resolution and fidelity of the seismic data. It is thus widely used in industry. However, it is difficult to ensure good coupling of the geophones with the seabed because of the impact of ocean flow, seafloor topography, and field operations; therefore, geophone data are seriously affected by the transfer function of the geophone-seabed coupling system. As a result, geophone data frequently have low signal-to-noise ratios (S/N), which causes large differences in amplitude, frequency, and phases between geophone and hydrophone data that severely affect dual-sensor summation. In contrast, the hydrophone detects changes in brine pressure and has no coupling issues with the seabed; thus, hydrophone data always have good S/N. First, in this paper, the mathematical expression of the transfer function between geophone and seabed is presented. Second, the transfer function of the geophone-seabed is estimated using hydrophone data as reference traces, and finally, the coupling correction based on the estimated transfer function is implemented. Using this processing, the amplitude and phase differences between geophone and hydrophone data are removed, and the S/N of the geophone data are improved. Synthetic and real data examples then show that our method is feasible and practical.

  6. Using BRDFs for accurate albedo calculations and adjacency effect corrections

    SciTech Connect

    Borel, C.C.; Gerstl, S.A.W.

    1996-09-01

    In this paper the authors discuss two uses of BRDFs in remote sensing: (1) in determining the clear sky top of the atmosphere (TOA) albedo, (2) in quantifying the effect of the BRDF on the adjacency point-spread function and on atmospheric corrections. The TOA spectral albedo is an important parameter retrieved by the Multi-angle Imaging Spectro-Radiometer (MISR). Its accuracy depends mainly on how well one can model the surface BRDF for many different situations. The authors present results from an algorithm which matches several semi-empirical functions to the nine MISR measured BRFs that are then numerically integrated to yield the clear sky TOA spectral albedo in four spectral channels. They show that absolute accuracies in the albedo of better than 1% are possible for the visible and better than 2% in the near infrared channels. Using a simplified extensive radiosity model, the authors show that the shape of the adjacency point-spread function (PSF) depends on the underlying surface BRDFs. The adjacency point-spread function at a given offset (x,y) from the center pixel is given by the integral of transmission-weighted products of BRDF and scattering phase function along the line of sight.

  7. Context-dependent effects of background colour in free recall with spatially grouped words.

    PubMed

    Sakai, Tetsuya; Isarida, Toshiko K; Isarida, Takeo

    2010-10-01

    Three experiments investigated context-dependent effects of background colour in free recall with groups of items. Undergraduates (N=113) intentionally studied 24 words presented in blocks of 6 on a computer screen with two different background colours. The two background colours were changed screen-by-screen randomly (random condition) or alternately (alternation condition) during the study period. A 30-second filled retention interval was imposed before an oral free-recall test. A signal for free recall was presented throughout the test on one of the colour background screens presented at study. Recalled words were classified as same- or different-context words according to whether the background colours at study and test were the same or different. The random condition produced significant context-dependent effects, whereas the alternation condition showed no context-dependent effects, regardless of whether the words were presented once or twice. Furthermore, the words presented on the same screen were clustered in recall, whereas the words presented against the same background colour but on different screens were not clustered. The present results imply: (1) background colours can cue spatially massed words; (2) background colours act as temporally local context; and (3) predictability of the next background colour modulates the context-dependent effect. PMID:20835947

  8. Effect of Peer Instruction on the Likelihood for Choosing the Correct Response to a Physiology Question

    ERIC Educational Resources Information Center

    Relling, Alejandro E.; Giuliodori, Mauricio J.

    2015-01-01

    The aims of the present study were to measure the effects of individual answer (correct vs. incorrect), individual answer of group members (no vs. some vs. all correct), self-confidence about the responses (low vs. mid vs. high), sex (female vs. male students), and group size (2-4 students) on the odds for change and for correctness after peer…

  9. The Effects of Background Music on Learning Disabled Elementary School Students' Performance in Writing

    ERIC Educational Resources Information Center

    Legutko, Robert S.; Trissler, Theodore T.

    2012-01-01

    This study investigated effects of background music on writing performance of nine 6th grade students with learning disabilities at one suburban public elementary school in the mid-Atlantic region of the United States. A single-subject A-B-A design was utilized, and results from graded writing prompts with and without background music over 21…

  10. The Effect of Background Experience and an Advance Organizer on the Attainment of Certain Science Concepts.

    ERIC Educational Resources Information Center

    McAdaragh, Mary Kathleen

    This study examined the effects of an advance organizer and background experience in science on the attainment of science concepts. Ninth-grade earth science students (N=90) were given the Dubbins Earth Science Test (DEST) and a Science Background Experience Inventory (SBEI) developed by the author. They were then placed into high, medium, and low…

  11. AdS{sub 3} backgrounds from 10D effective action of heterotic string theory

    SciTech Connect

    Dominis Prester, Predrag

    2010-02-15

    We present a method for calculating solutions and corresponding central charges for backgrounds with AdS{sub 3} and S{sup k} factors in {alpha}{sup '}-exact fashion from the full tree-level low-energy effective action of heterotic string theory. Three examples are explicitly presented: AdS{sub 3}xS{sup 3}xT{sup 4}, AdS{sub 3}xS{sup 2}xS{sup 1}xT{sup 4}, and AdS{sub 3}xS{sup 3}xS{sup 3}xS{sup 1}. Crucial property which enabled our analysis is vanishing of the Riemann tensor calculated from connection with ''{sigma}-model torsion.'' We show the following: (i) Chern-Simons terms are the only source of {alpha}{sup '} corrections not only in BPS, but also in non-BPS cases, suggesting a possible extension of general method of Kraus and Larsen, (ii) our results are in agreement with some conjectures on the form of the part of tree-level Lagrangian not connected to a mixed Chern-Simons term by supersymmetry (and present in all supersymmetric string theories), (iii) new {alpha}{sup '}-exact result for central charges in AdS{sub 3}xS{sup 3}xS{sup 3}xS{sup 1} geometry. As a tool we used our generalization of Sen's E-function formalism to AdS{sub p} with p>2, and paid special attention to proper definition of asymptotic charges.

  12. Corrective cosmetics are effective for women with facial pigmentary disorders.

    PubMed

    Balkrishnan, Rajesh; McMichael, Amy J; Hu, Judy Y; Camacho, Fabian T; Kaur, Mandeep; Bouloc, Anne; Rapp, Stephen R; Feldman, Steven R

    2005-03-01

    Visible facial lesions are a common and burdensome skin problem. This study examines the impact of corrective cosmetics in women with severe facial pigmentary disorders. Enrollment consisted of 73 women with one or more of the following conditions: acne, dermatosis papulosis, hypopigmentation, lentigines, melasma, rosacea, vascular proliferations, or other facial scars. The corrective cosmetic (Dermablend) was applied at the initial visit, at which time instructions and a supply of product were provided. Assessments were conducted at baseline, 2-week, 4-week, and 3-month follow-up visits on 63 patients using the Skindex-16. The corrective cosmetic was well tolerated. There was improvement in Skindex-16 scores after application of the corrective cosmetic, which continued at each follow-up visit and after adjustment for baseline confounders using multiple regression analyses. At 3 months, there was a 30% improvement in Skindex-16 score (P < .001). The corrective cosmetic was well tolerated and represents a valuable option that dermatologists can offer to patients with these conditions. PMID:15839363

  13. Hip prostheses during pelvic irradiation: effects and corrections

    SciTech Connect

    Hazuka, M.B.; Ibbott, G.S.; Kinzie, J.J.

    1988-06-01

    Treatment of pelvic malignancies frequently includes the use of lateral, arc, or rotational fields. The presence of hip prostheses in these treatment fields will perturb the dose distribution. Correction factors for metal-based alloys used in artificial hips have not previously been reported. Prostheses constructed from frequently used alloys were obtained and measurements were made of the transmission of 4MV and 10MV photons. These measured data were compared with computed correction factors. The computer uses the ratio of tissue-maximum ratios (TMR's) method of heterogeneity correction. The computer was provided with both the physical density and the relative electron density of each prosthesis for comparison purposes, since electron densities for hip prostheses are not widely known. Correction factors determined from electron densities demonstrated better agreement with measured data. The ratio of TMR's correction algorithm does not consider the contribution of scattered radiation in the dose computations. Consequently, a small adjustment to the relative electron density of the prosthetic hip was required at lower X ray beam energies. Agreement was satisfactory for higher energy X rays, and thus no adjustment was necessary. Relative electron densities and adjusted electron densities for alloys used in artificial hips are provided for computer-aided treatment planning. Recommendations for incorporating the hip prosthesis into the treatment planning process are also provided.

  14. Effect of anatomical backgrounds on detectability in volumetric cone beam CT images

    NASA Astrophysics Data System (ADS)

    Han, Minah; Park, Subok; Baek, Jongduk

    2016-03-01

    As anatomical noise is often a dominating factor affecting signal detection in medical imaging, we investigate the effects of anatomical backgrounds on signal detection in volumetric cone beam CT images. Signal detection performances are compared between transverse and longitudinal planes with either uniform or anatomical backgrounds. Sphere objects with diameters of 1mm, 5mm, 8mm, and 11mm are used as the signals. Three-dimensional (3D) anatomical backgrounds are generated using an anatomical noise power spectrum, 1/fβ, with β=3, equivalent to mammographic background [1]. The mean voxel value of the 3D anatomical backgrounds is used as an attenuation coefficient of the uniform background. Noisy projection data are acquired by the forward projection of the uniform and anatomical 3D backgrounds with/without sphere lesions and by the addition of quantum noise. Then, images are reconstructed by an FDK algorithm [2]. For each signal size, signal detection performances in transverse and longitudinal planes are measured by calculating the task SNR of a channelized Hotelling observer with Laguerre-Gauss channels. In the uniform background case, transverse planes yield higher task SNR values for all sphere diameters but 1mm. In the anatomical background case, longitudinal planes yield higher task SNR values for all signal diameters. The results indicate that it is beneficial to use longitudinal planes to detect spherical signals in anatomical backgrounds.

  15. Effect of Background Emissivity on Gas Detection in Thermal Hyperspectral Imagery

    SciTech Connect

    Walsh, Stephen J.; Tardiff, Mark F.; Chilton, Lawrence K.; Metoyer, Candace N.

    2008-10-02

    Detecting and identifying weak gaseous plumes using thermal imaging data is complicated by many factors. These include variability due to atmosphere, ground and plume temper- ature, and background clutter. This paper presents an analysis of one formulation of the physics-based radiance model, which describes at-sensor observed radiance. The background emissivity and plume/ground temperatures are isolated, and their effects on net chemical signal are described. This analysis shows that the plume’s physical state, emission or absorption, is directly dependent on the background emissivity. It then describes what conditions on the background emissivity have inhibiting effects on the net chemical signal. These claims are illustrated by analyzing synthetic hyperspectral imaging data with the Adaptive Matched Filter using four chemicals and three distinct background emissivities. Two chemicals (Carbontetrachloride and Tetraflourosilane) in the analysis had a very strong relationship with the background emissivities: they exhibited absorbance over a small range of wavenumbers and the background emissivities showed a consistent ordering at these wavenumbers. Analysis of simulated hyperspectral images containing these chemicals showed complete agreement with the analysis of the physics-based model that described when the background emissivities would have inhibiting effects on gas detection. The other chemicals considered (Ammonia and Tributylphosphate) exhibited very complex absorbance structure across the longwave infrared spectrum. Analysis of images containing these chemicals revealed that the the analysis of the physics-based model did not hold completely for these complex chemicals but did suggest that gas detection was dominated by their dominant absorbance features. These results provide some explanation of the effect of the background emissivity on gas detection and a more general exploration of gas absorbance/background emissivity variability and their effects on

  16. The Joint Effects of Background Selection and Genetic Recombination on Local Gene Genealogies

    PubMed Central

    Zeng, Kai; Charlesworth, Brian

    2011-01-01

    Background selection, the effects of the continual removal of deleterious mutations by natural selection on variability at linked sites, is potentially a major determinant of DNA sequence variability. However, the joint effects of background selection and genetic recombination on the shape of the neutral gene genealogy have proved hard to study analytically. The only existing formula concerns the mean coalescent time for a pair of alleles, making it difficult to assess the importance of background selection from genome-wide data on sequence polymorphism. Here we develop a structured coalescent model of background selection with recombination and implement it in a computer program that efficiently generates neutral gene genealogies for an arbitrary sample size. We check the validity of the structured coalescent model against forward-in-time simulations and show that it accurately captures the effects of background selection. The model produces more accurate predictions of the mean coalescent time than the existing formula and supports the conclusion that the effect of background selection is greater in the interior of a deleterious region than at its boundaries. The level of linkage disequilibrium between sites is elevated by background selection, to an extent that is well summarized by a change in effective population size. The structured coalescent model is readily extendable to more realistic situations and should prove useful for analyzing genome-wide polymorphism data. PMID:21705759

  17. Coping with Misinformation: Corrections, Backfire Effects, and Choice Architectures

    NASA Astrophysics Data System (ADS)

    Lewandowsky, S.; Cook, J.; Ecker, U. K.

    2012-12-01

    The widespread prevalence and persistence of misinformation about many important scientific issues, from climate change to vaccinations or the link between HIV and AIDS, must give rise to concern. We first review the mechanisms by which such misinformation is disseminated in society, both inadvertently and purposely. We then survey and explain the cognitive factors that often render misinformation resistant to correction. We answer the question why retractions of misinformation can be so ineffective and why they can even backfire and ironically increase misbelief. We discuss the overriding role of ideology and personal worldviews in the resistance of misinformation to correction and show how their role can be attenuated. We discuss the risks associated with repeating misinformation while seeking to correct it and we point to the design of "choice architectures" as an alternative to the attempt to retract misinformation.

  18. Atomic electron energies including relativistic effects and quantum electrodynamic corrections

    NASA Technical Reports Server (NTRS)

    Aoyagi, M.; Chen, M. H.; Crasemann, B.; Huang, K. N.; Mark, H.

    1977-01-01

    Atomic electron energies have been calculated relativistically. Hartree-Fock-Slater wave functions served as zeroth-order eigenfunctions to compute the expectation of the total Hamiltonian. A first order correction to the local approximation was thus included. Quantum-electrodynamic corrections were made. For all orbitals in all atoms with 2 less than or equal to Z less than or equal to 106, the following quantities are listed: total energies, electron kinetic energies, electron-nucleus potential energies, electron-electron potential energies consisting of electrostatic and Breit interaction (magnetic and retardation) terms, and vacuum polarization energies. These results will serve for detailed comparison of calculations based on other approaches. The magnitude of quantum electrodynamic corrections is exhibited quantitatively for each state.

  19. Analyses and experiments of background sunlight's effects on laser detection system

    NASA Astrophysics Data System (ADS)

    Guo, Hao; Yin, Rui-guang; Ma, Na; Liang, Wei-wei; Li, Bo

    2015-10-01

    Background sunlight effect the technical performance of laser detection system significantly. Analyses and experiments were done to find the degree and regularity of effects of background sunlight on laser detection system. At first, we established the theoretical model of laser detection probability curve. We emulated and analysed the effects on probability curve under different sunlight intensity by the model. Moreover, we got the variation regularity of parameter in probability curve. Secondly, we proposed a prediction method of probability curve, which deduced the detecting parameter from measured data. The method can not only get the probability curve in arbitrary background sunlight by a measured probability curve in typical background sunlight, but also calculate the sensitivity of laser detection systems by probability curve at the specified probability. Thirdly, we measured the probability curves under three types of background sunlight. The illumination conditions in experiments included fine, overcast and night. These three curves can be used as reference to deduce other curves. Using model, method, and measured data mentioned above, we finally finished the analyses and appraisal of the effects of background sunlight on typical laser detection system. The research findings can provide the theoretical reference and technical support for adaptability evaluation of typical laser detection systems in different background sunlight.

  20. Effects of Psychoeducation for Offenders in a Community Correctional Facility

    ERIC Educational Resources Information Center

    Liau, Albert K.; Shively, Randy; Horn, Mary; Landau, Jennifer; Barriga, Alvaro; Gibbs, John C.

    2004-01-01

    The present study provided a randomized outcome evaluation of the psychoeducational component of the EQUIP program. The psychoeducational curriculum was implemented in a community correctional facility for adult felony offenders. The psychoeducational curriculum is designed to remedy offenders' delays in moral judgment maturity, social cognitive…

  1. Effect of radiative corrections on the solar neutrino spectrum

    SciTech Connect

    Batkin, I.S.; Sundaresan, M.K.

    1995-11-01

    In this paper we calculate the changes to the solar neutrino spectrum arising from the radiative corrections in the {beta} decay processes responsible for the production of the neutrinos. Explicit results are given for the neutrinos arising from the {ital pp} reaction and for the {sup 8}B neutrinos.

  2. The Effectiveness of Two Methods of Correcting Formal Error.

    ERIC Educational Resources Information Center

    Eaton, Angela

    2003-01-01

    Reports on a study in progress. Considers if papers produced by students who learned from reduced-grammar methods have fewer errors than papers produced by students who learned from traditional grammar handbooks. Explores if students who use a computer to search for errors correct more errors than students who search manually. Examines if students…

  3. Effect of Background Pressure on the Performance and Plume of the HiVHAc Hall Thruster

    NASA Technical Reports Server (NTRS)

    Huang, Wensheng; Kamhawi, Hani; Haag, Thomas

    2013-01-01

    During the Single String Integration Test of the NASA HiVHAc Hall thruster, a number of plasma diagnostics were implemented to study the effect of varying facility background pressure on thruster operation. These diagnostics include thrust stand, Faraday probe, ExB probe, and retarding potential analyzer. The test results indicated a rise in thrust and discharge current with background pressure. There was also a decrease in ion energy per charge, an increase in multiply-charged species production, a decrease in plume divergence, and a decrease in ion beam current with increasing background pressure. A simplified ingestion model was applied to determine the maximum acceptable background pressure for thrust measurement. The maximum acceptable ingestion percentage was found to be around 1%. Examination of the diagnostics results suggest the ionization and acceleration zones of the thruster were shifting upstream with increasing background pressure.

  4. Effect of Background Pressure on the Plasma Oscillation Characteristics of the HiVHAc Hall Thruster

    NASA Technical Reports Server (NTRS)

    Huang, Wensheng; Kamhawi, Hani; Lobbia, Robert B.; Brown, Daniel L.

    2014-01-01

    During a component compatibility test of the NASA HiVHAc Hall thruster, a number of plasma diagnostics were implemented to study the effect of varying facility background pressure on thruster operation. These diagnostics characterized the thruster performance, the plume, and the plasma oscillations in the thruster. Thruster performance and plume characteristics as functions of background pressure were previously published. This paper focuses on changes in the plasma oscillation characteristics with changing background pressure. The diagnostics used to study plasma oscillations include a high-speed camera and a set of high-speed Langmuir probes. The results show a rise in the oscillation frequency of the "breathing" mode with rising background pressure, which is hypothesized to be due to a shortening acceleration/ionization zone. An attempt is made to apply a simplified ingestion model to the data. The combined results are used to estimate the maximum acceptable background pressure for performance and wear testing.

  5. Radiative corrections to the Casimir effect at nonzero temperatures

    SciTech Connect

    Wieczorek, E.; Robaschik, D.; Scharnhorst, K.

    1986-10-01

    Quantum electrodynamics at nonzero temperatures with boundary conditions is formulated on the basis of the functional integral using the results of previous studies (Sov. J. Nucl. Phys. 39, 663 (1984); Ann. Phys. (N.Y.) 165, 192 (1985)). The Matsubara imaginary-time formalism and the thermal field approach of perturbation theory are used. The loop corrections to the free-energy functional are calculated in a physically reasonable limit.

  6. Surface-effect corrections for the solar model

    NASA Astrophysics Data System (ADS)

    Magic, Z.; Weiss, A.

    2016-07-01

    Context. Solar p-mode oscillations exhibit a systematic offset towards higher frequencies due to shortcomings in the 1D stellar structure models, in particular, the lack of turbulent pressure in the superadiabatic layers just below the optical surface, arising from the convective velocity field. Aims: We study the influence of the turbulent expansion, chemical composition, and magnetic fields on the stratification in the upper layers of the solar models in comparison with solar observations. Furthermore, we test alternative ⟨3D⟩ averages for improved results on the oscillation frequencies. Methods: We appended temporally and spatially averaged ⟨3D⟩ stratifications to 1D models to compute adiabatic oscillation frequencies that we then tested against solar observations. We also developed depth-dependent corrections for the solar 1D model, for which we expanded the geometrical depth to match the pressure stratification of the solar ⟨3D⟩ model, and we reduced the density that is caused by the turbulent pressure. Results: We obtain the same results with our ⟨3D⟩ models as have been reported previously. Our depth-dependent corrected 1D models match the observations to almost a similar extent as the ⟨3D⟩ model. We find that correcting for the expansion of the geometrical depth and the reducing of the density are both equally necessary. Interestingly, the influence of the adiabatic exponent Γ1 is less pronounced than anticipated. The turbulent elevation directly from the ⟨3D⟩ model does not match the observations properly. Considering different reference depth scales for the ⟨3D⟩ averaging leads to very similar frequencies. Solar models with high metal abundances in their initial chemical composition match the low-frequency part much better. We find a linear relation between the p-mode frequency shift and the vertical magnetic field strength with δvnl = 26.21Bz [μHz/kG], which is able to render the solar activity cycles correctly.

  7. Effects of lump characteristics on plutonium self absorption correction methods

    SciTech Connect

    Curtis, D. C.; Wormald, M. R.; Croft, S.

    2007-07-01

    An evaluation study has been undertaken to assess the robustness of several published Pu self-absorption correction methods against variation in size, shape, density etc. for use in the gamma assay of nuclear waste. The correction methods studied are a numerical plutonium self absorption correction (PuSAC) technique, the Fleissner 2-line, Fleissner 3-line and Infinite Energy Extrapolation methods with both linear and polynomial extrapolation to 1/E=0. The performance of these methods has been compared for a limited set of measured encapsulated PuO{sub 2} sources plus a range of modelled unencapsulated Pu lumps. An indication of the magnitude of the uncertainties of the numerical PuSAC method has been determined for cases of blind assays where the Pu material, shape and distribution are unknown with the aim of ultimately applying it to real waste. The importance of the range of Pu lumps used in the baseline modelled dataset has been examined. Data are presented to illustrate how the uncertainties in the method are affected by the shape, composition, density, number and mass distribution of Pu particles in a sample for a given modelled base dataset. (authors)

  8. Effect of Background Pressure on the Plasma Oscillation Characteristics of the HiVHAc Hall Thruster

    NASA Technical Reports Server (NTRS)

    Huang, Wensheng; Kamhawi, Hani; Lobbia, Robert B.; Brown, Daniel L.

    2014-01-01

    During a component compatibility test of the NASA HiVHAc Hall thruster, a high-speed camera and a set of high-speed Langmuir probes were implemented to study the effect of varying facility background pressure on thruster operation. The results show a rise in the oscillation frequency of the breathing mode with rising background pressure, which is hypothesized to be due to a shortening accelerationionization zone. An attempt is made to apply a simplified ingestion model to the data. The combined results are used to estimate the maximum acceptable background pressure for performance and wear testing.

  9. A Synthesis of the Effects of Correctional Education on the Academic Outcomes of Incarcerated Adults

    ERIC Educational Resources Information Center

    Reed, Deborah K.

    2015-01-01

    Most evaluations of the effectiveness of correctional education use the distal outcomes of recidivism and post-release employment as the dependent variables (e.g., Aos et al., 2006; Davis et al., 2013). This synthesis sought to determine the effectiveness of correctional education at improving proximal academic outcomes among incarcerated adult…

  10. Effect of peer instruction on the likelihood for choosing the correct response to a physiology question.

    PubMed

    Relling, Alejandro E; Giuliodori, Mauricio J

    2015-09-01

    The aims of the present study were to measure the effects of individual answer (correct vs. incorrect), individual answer of group members (no vs. some vs. all correct), self-confidence about the responses (low vs. mid vs. high), sex (female vs. male students), and group size (2-4 students) on the odds for change and for correctness after peer instruction in a veterinary physiology course (n = 101 students). Data were assessed by multivariable logistic regression analysis. The likelihood for change after peer instruction increased when the confidence on an individual answer was low (P < 0.01), when the answer was incorrect (P < 0.01), and when group members had different responses (P < 0.01). The likelihood for correctness after peer instruction increased when the confidence in group answers was high (P < 0.01), when the individual answer was correct (P < 0.01), and when at least one of the group members had the correct response (P < 0.01). After peer discussion, more changes were from incorrect to correct responses than vice versa (72% vs. 28%, P < 0.01). Changes to correct answers occurred after discussion with peers having both the correct individual response (76% of times) and also the incorrect individual answer (24% of times). In conclusion, the benefits of peer instruction are due to students having correct answers generally prevail in discussions. Also, students who all have incorrect answers can get the correct answer through debate and discussion. PMID:26330032

  11. Study on camouflage effect of targets with different characteristics under typical background

    NASA Astrophysics Data System (ADS)

    Gao, Shaoshu; Jin, Weiqi; Wang, Jihui; Wang, He; Li, Hailan; Guo, Aiyan

    2010-10-01

    With the rapid development of infrared detecting and homing technology, it is important for us to analyze infrared camouflage effect of ground targets to improve the survivability. In the paper, factors such as the effect of atmosphere between detectors and targets, characteristics of targets and background and atmospheric radiance including directly transmitted solar irradiance are taken into account in long-distance detecting. The concept of RARD (relative apparent radiance difference) between targets and background is proposed and the camouflage effect of ground targets can be evaluated precisely. MODTRAN 4.0 is used to analyze the camouflage effect of targets. In MODTRAN, solar zenith angle, common background, emissivity and temperature of targets are selected to calculate RARD under certain atmosphere condition. Simulation results show that RARD is affected by the solar zenith angle significantly in middle infrared wavelength region, but hardly in long-wave infrared region. Under the special background, according to the target temperature, proper coating with unchanged emissivity is selected to camouflage the target all day in long-wave infrared region. However, for the changing background, the stealth coating with variable emissivity should be adopted. In addition, for the same target, it is even more difficult to achieve good camouflage effect at both medium infrared band and long wave infrared band.

  12. A Dynamic Analysis of the Effects of Intelligence and Socioeconomic Background on Job-Market Success

    ERIC Educational Resources Information Center

    Ganzach, Yoav

    2011-01-01

    We compare the effects of socioeconomic background (SEB) and intelligence on wage trajectories in a dynamic growth modeling framework in a sample that had completed just 12 years of education. I show that the main difference between the two is that SEB affected wages solely by its effect on entry pay whereas intelligence affected wages primarily…

  13. Synergic effects of 10°/s constant rotation and rotating background on visual cognitive processing

    NASA Astrophysics Data System (ADS)

    He, Siyang; Cao, Yi; Zhao, Qi; Tan, Cheng; Niu, Dongbin

    In previous studies we have found that constant low-speed rotation facilitated the auditory cognitive process and constant velocity rotation background sped up the perception, recognition and assessment process of visual stimuli. In the condition of constant low-speed rotation body is exposed into a new physical state. In this study the variations of human brain's cognitive process under the complex condition of constant low-speed rotation and visual rotation backgrounds with different speed were explored. 14 university students participated in the ex-periment. EEG signals were recorded when they were performing three different cognitive tasks with increasing mental load, that is no response task, selective switch responses task and selec-tive mental arithmetic task. Rotary chair was used to create constant low-speed10/srotation. Four kinds of background were used in this experiment, they were normal black background and constant 30o /s, 45o /s or 60o /s rotating simulated star background. The P1 and N1 compo-nents of brain event-related potentials (ERP) were analyzed to detect the early visual cognitive processing changes. It was found that compared with task performed under other backgrounds, the posterior P1 and N1 latencies were shortened under 45o /s rotating background in all kinds of cognitive tasks. In the no response task, compared with task performed under black back-ground, the posterior N1 latencies were delayed under 30o /s rotating background. In the selec-tive switch responses task and selective mental arithmetic task, compared with task performed under other background, the P1 latencies were lengthened under 60o /s rotating background, but the average amplitudes of the posterior P1 and N1 were increased. It was suggested that under constant 10/s rotation, the facilitated effect of rotating visual background were changed to an inhibited one in 30o /s rotating background. Under vestibular new environment, not all of the rotating backgrounds

  14. Effect of background music on maximum acceptable weight of manual lifting tasks.

    PubMed

    Yu, Ruifeng

    2014-01-01

    This study used the psychophysical approach to investigate the impact of tempo and volume of background music on the maximum acceptable weight of lift (MAWL), heart rate (HR) and rating of perceived exertion (RPE) of participants engaged in lifting. Ten male college students participated in this study. They lifted a box from the floor, walked 1-2 steps as required, placed the box on a table and walked back twice per minute. The results showed that the tempo of music had a significant effect on both MAWL and HR. Fast tempo background music resulted in higher MAWL and HR values than those resulting from slow tempo music. The effects of both the tempo and volume on the RPE were insignificant. The results of this study suggest fast tempo background music may be used in manual materials handling tasks to increase performance without increasing perceived exertion because of its ergogenic effect on human psychology and physiology. PMID:25189748

  15. Deformed special relativity as an effective theory of measurements on quantum gravitational backgrounds

    SciTech Connect

    Aloisio, R.; Grillo, A.; Galante, A.; Liberati, S.; Luzio, E.; Mendez, F.

    2006-02-15

    In this article we elaborate on a recently proposed interpretation of deformed special relativity (DSR) as an effective measurement theory in the presence of non-negligible (albeit small) quantum gravitational fluctuations. We provide several heuristic arguments to explain how such a new theory can emerge and discuss the possible observational consequences of this framework. Given that our discussion considers leading order corrections to the standard dispersion relations, our results apply to a very wide class of possible modifications of special relativity.

  16. The effect of finite field size on classification and atmospheric correction

    NASA Technical Reports Server (NTRS)

    Kaufman, Y. J.; Fraser, R. S.

    1981-01-01

    The atmospheric effect on the upward radiance of sunlight scattered from the Earth-atmosphere system is strongly influenced by the contrasts between fields and their sizes. For a given atmospheric turbidity, the atmospheric effect on classification of surface features is much stronger for nonuniform surfaces than for uniform surfaces. Therefore, the classification accuracy of agricultural fields and urban areas is dependent not only on the optical characteristics of the atmosphere, but also on the size of the surface do not account for the nonuniformity of the surface have only a slight effect on the classification accuracy; in other cases the classification accuracy descreases. The radiances above finite fields were computed to simulate radiances measured by a satellite. A simulation case including 11 agricultural fields and four natural fields (water, soil, savanah, and forest) was used to test the effect of the size of the background reflectance and the optical thickness of the atmosphere on classification accuracy. It is concluded that new atmospheric correction methods, which take into account the finite size of the fields, have to be developed to improve significantly the classification accuracy.

  17. Correction factors for saturation effects in white light and laser absorption spectroscopy for application to low pressure plasmas

    SciTech Connect

    Briefi, S.; Wimmer, C.; Fantz, U.

    2012-05-15

    In white light absorption spectroscopy, the broadening of the absorption signal due to the apparatus profile of the spectrometer may lead to an underestimation of the determined density as one measures an apparent optical depth. This is in particular true for high optical depth where saturation effects of the transmitted intensity occur. Provided that the line profile of the absorption line is known, the apparent optical depth effect can be accounted for by introducing a correction factor. The impact of the saturation and the approach of considering the effect are demonstrated for argon and indium lines in low pressure plasmas where correction factors of one order of magnitude or even higher are reached very easily. For the indium line, the hyperfine splitting has been taken into account. In laser absorption, the line profile is resolved. However, the weak but rather broad background emission of the laser diode can cause a saturation signal at the photo diode resulting also in an underestimation of the density obtained from the analysis. It is shown that this can be taken into account by fitting the theoretical line profile to the measured absorption signal which yields also a correction factor. The method is introduced and demonstrated at the example of the cesium resonance line including the hyperfine splitting. Typical correction factors around two are obtained for the cesium ground state density at conditions of a low pressure negative hydrogen ion source in which cesium is evaporated to enhance the negative ion production.

  18. The effect of background music and song texts on the emotional understanding of children with autism.

    PubMed

    Katagiri, June

    2009-01-01

    The purpose of this study was to examine the effect of background music and song texts to teach emotional understanding to children with autism. Participants were 12 students (mean age 11.5 years) with a primary diagnosis of autism who were attending schools in Japan. Each participant was taught four emotions to decode and encode: happiness, sadness, anger, and fear by the counterbalanced treatment-order. The treatment consisted of the four conditions: (a) no contact control (NCC)--no purposeful teaching of the selected emotion, (b) contact control (CC)--teaching the selected emotion using verbal instructions alone, (c) background music (BM)--teaching the selected emotion by verbal instructions with background music representing the emotion, and singing songs (SS)--teaching the selected emotion by singing specially composed songs about the emotion. Participants were given a pretest and a posttest and received 8 individual sessions between these tests. The results indicated that all participants improved significantly in their understanding of the four selected emotions. Background music was significantly more effective than the other three conditions in improving participants' emotional understanding. The findings suggest that background music can be an effective tool to increase emotional understanding in children with autism, which is crucial to their social interactions. PMID:19256729

  19. Effective detection of corrected dystrophin loci in mdx mouse myogenic precursors.

    PubMed

    Todaro, Marian; Quigley, Anita; Kita, Magdalena; Chin, Judy; Lowes, Kym; Kornberg, Andrew J; Cook, Mark J; Kapsa, Robert

    2007-08-01

    Targeted corrective gene conversion (TCGC) holds much promise as a future therapy for many hereditary diseases in humans. Mutation correction frequencies varying between 0.0001% and 40% have been reported using chimeraplasty, oligoplasty, triplex-forming oligonucleotides, and small corrective PCR amplicons (CPA). However, PCR technologies used to detect correction events risk either falsely indicating or greatly exaggerating the presence of corrected loci. This is a problem that is considerably exacerbated by attempted improvement of the TCGC system using high corrective nucleic acid (CNA) to nuclear ratios. Small fragment homologous replacement (SFHR)-mediated correction of the exon 23 dystrophin (DMD) gene mutation in the mdx mouse model of DMD has been used in this study to evaluate the effect of increasing CPA amounts. In these experiments, we detected extremely high levels of apparently corrected loci and determined that at higher CNA to nuclear ratios the extent of locus correction was highly exaggerated by residual CNA species in the nucleic acids extracted from the treated cells. This study describes a generic locus-specific detection protocol designed to eradicate residual CNA species and avoid the artifactual or exaggerated detection of gene correction. PMID:17394239

  20. An Evaluation of Information Criteria Use for Correct Cross-Classified Random Effects Model Selection

    ERIC Educational Resources Information Center

    Beretvas, S. Natasha; Murphy, Daniel L.

    2013-01-01

    The authors assessed correct model identification rates of Akaike's information criterion (AIC), corrected criterion (AICC), consistent AIC (CAIC), Hannon and Quinn's information criterion (HQIC), and Bayesian information criterion (BIC) for selecting among cross-classified random effects models. Performance of default values for the 5…

  1. Simultaneous correction of bandpass and stray-light effects in array spectroradiometer data

    NASA Astrophysics Data System (ADS)

    Nevas, Saulius; Wübbeler, Gerd; Sperling, Armin; Elster, Clemens; Teuber, Annette

    2012-04-01

    A method for the simultaneous correction of bandpass and stray-light effects in array spectroradiometer data is presented. The method is based on the inversion of the instrument matrix of a device determined with the help of tuneable lasers. By applying the Tikhonov regularization technique, a straightforward correction of the measurement results is possible.

  2. Effects of Classwide Peer Tutoring on the Number of Words Spelled Correctly by Students with LD

    ERIC Educational Resources Information Center

    Burks, M

    2004-01-01

    The author analyzed the effects that Classwide Peer Tutoring (CWPT) had on the number of words in a spelling test that students with learning disabilities in reading and writing spelled correctly. By means of an ABAB design, she investigated using CWPT in relation to the amount of correctly spelled words. The results indicated that the number of…

  3. The Effect of Age-Correction on IQ Scores among School-Aged Children Born Preterm

    ERIC Educational Resources Information Center

    Roberts, Rachel M.; George, Wing Man; Cole, Carolyn; Marshall, Peter; Ellison, Vanessa; Fabel, Helen

    2013-01-01

    This study examined the effect of age-correction on IQ scores among preterm school-aged children. Data from the Flinders Medical Centre Neonatal Unit Follow-up Program for 81 children aged five years and assessed with the WPPSI-III, and 177 children aged eight years and assessed with the WISC-IV, were analysed. Corrected IQ scores were…

  4. [Contrast effects of background stimulus person on attitude similarity judgement and interpersonal attraction: a study of topic familiarity effect].

    PubMed

    Tajima, T

    2000-10-01

    The purpose of this study was to examine the effects of a background stimulus person on attitude similarity judgement and interpersonal attraction. Mascaro and Graves (1973) argued that a contrast effect on perception of similarity mediated interpersonal attraction. In the present experiment, it was hypothesized that topic familiarity moderated the effects of a background stimulus person on attitude similarity judgement and interpersonal attraction. One hundred twenty-two (122) female students were randomly assigned to four groups, formed by two levels of topic familiarity and two levels of similarity for the background stimulus person. They saw the attitudes of two stimulus persons together, and were asked to rate perceived similarity and interpersonal attraction. Results showed that in familiar topic condition, contrast effect was not found for attitude similarity judgement, but it was found for interpersonal attraction. The finding suggested that presence of a background stimulus person immediately led to the contrast effect on interpersonal attraction. PMID:11140256

  5. Coastal Zone Color Scanner atmospheric correction algorithm: multiple scattering effects.

    PubMed

    Gordon, H R; Castaño, D J

    1987-06-01

    An analysis of the errors due to multiple scattering which are expected to be encountered in application of the current Coastal Zone Color Scanner (CZCS) atmospheric correction algorithm is presented in detail. This was prompted by the observations of others that significant errors would be encountered if the present algorithm were applied to a hypothetical instrument possessing higher radiometric sensitivity than the present CZCS. This study provides CZCS users sufficient information with which to judge the efficacy of the current algorithm with the current sensor and enables them to estimate the impact of the algorithm-induced errors on their applications in a variety of situations. The greatest source of error is the assumption that the molecular and aerosol contributions to the total radiance observed at the sensor can be computed separately. This leads to the requirement that a value epsilon'(lambda,lambda(0)) for the atmospheric correction parameter, which bears little resemblance to its theoretically meaningful counterpart, must usually be employed in the algorithm to obtain an accurate atmospheric correction. The behavior of '(lambda,lambda(0)) with the aerosol optical thickness and aerosol phase function is thoroughly investigated through realistic modeling of radiative transfer in a stratified atmosphere over a Fresnel reflecting ocean. A unique feature of the analysis is that it is carried out in scan coordinates rather than typical earth-sun coordinates allowing elucidation of the errors along typical CZCS scan lines; this is important since, in the normal application of the algorithm, it is assumed that the same value of can be used for an entire CZCS scene or at least for a reasonably large subscene. Two types of variation of ' are found in models for which it would be constant in the single scattering approximation: (1) variation with scan angle in scenes in which a relatively large portion of the aerosol scattering phase function would be examined

  6. Exploring Effects of Background Context Familiarity and Signaling on Comprehension, Recall, and Cognitive Load

    ERIC Educational Resources Information Center

    Song, Minjung; Bruning, Roger

    2016-01-01

    This study was designed to explore the effects of different geographical background contexts and signalling for information about global warming on comprehension, recall and cognitive load. Two different geographical contexts, US and Korean, were employed to frame explanations of global warming phenomena to US students. Two signalling conditions…

  7. The Effect of Learning Background and Imagery Cognitive Development on Visual Perception

    ERIC Educational Resources Information Center

    Chiang, Shyh-Bao; Sun, Chun-Wang

    2013-01-01

    This research looked into the effect of how cognitive development toward imagery is formed through visual perception by means of a quantitative questionnaire. The main variable was the difference between the learning backgrounds of the interviewees. A two-way ANOVA mixed design was the statistical method used for the analysis of the 2 × 4 (2 by 4)…

  8. Effects of Teacher Educational Background and Experience on Student Achievement in the Early Grades

    ERIC Educational Resources Information Center

    Leak, James Alexander

    2012-01-01

    This dissertation examines the relationship between teacher educational background, teacher experience, and student achievement in preschool, kindergarten, and first grade. The first essay of this dissertation, "Effects of Teacher Degree Level, Coursework, and Certification on Student Achievement in Math and Reading in Kindergarten,"…

  9. Exploring the Effect of Background Knowledge and Text Cohesion on Learning from Texts in Computer Science

    ERIC Educational Resources Information Center

    Gasparinatou, Alexandra; Grigoriadou, Maria

    2013-01-01

    In this study, we examine the effect of background knowledge and local cohesion on learning from texts. The study is based on construction-integration model. Participants were 176 undergraduate students who read a Computer Science text. Half of the participants read a text of maximum local cohesion and the other a text of minimum local cohesion.…

  10. The Effects of Lesson Screen Background Color on Declarative and Structural Knowledge

    ERIC Educational Resources Information Center

    Clariana, Roy B.; Prestera, Gustavo E.

    2009-01-01

    This experimental investigation replicates previous investigations of the effects of left margin screen background color hue to signal lesson sections on declarative knowledge and extends those investigations by adding a measure of structural knowledge. Participants (N = 80) were randomly assigned to receive 1 of 4 computer-based lesson treatments…

  11. Decreasing Reading Differences in Children from Disadvantaged Backgrounds: The Effects of an Early Literacy Intervention

    ERIC Educational Resources Information Center

    Hagans, Kristi S.; Good, Roland H., III

    2013-01-01

    Children from low socioeconomic backgrounds (SES) are at increased risk of reading problems. Although phonological awareness consistently emerges as a critical literacy skill for children, little research exists regarding the effects of the acquisition of phonological awareness skills on decreasing the reading achievement gap between children of…

  12. Effects of Age, Gender and Educational Background on Strength of Motivation for Medical School

    ERIC Educational Resources Information Center

    Kusurkar, Rashmi; Kruitwagen, Cas; ten Cate, Olle; Croiset, Gerda

    2010-01-01

    The aim of this study was to determine the effects of selection, educational background, age and gender on strength of motivation to attend and pursue medical school. Graduate entry (GE) medical students (having Bachelor's degree in Life Sciences or related field) and Non-Graduate Entry (NGE) medical students (having only completed high school),…

  13. Effects of Stimulus Characteristics and Background Music on Foreign Language Vocabulary Learning and Forgetting

    ERIC Educational Resources Information Center

    de Groot, Annette M. B.

    2006-01-01

    This study examined the effects of three stimulus variables and background music on paired-associate learning of foreign language (FL) vocabulary. The stimulus variables were the frequency and concreteness of the native language (L1) words and the (phonotactical) typicality of the FL words. Sixty-four L1-FL pairs were presented for learning six…

  14. Corrections for matrix effects in X-ray fluorescence analysis—A tutorial

    NASA Astrophysics Data System (ADS)

    Rousseau, Richard M.

    2006-07-01

    This paper presents the basic concepts of the mathematical correction for matrix effects in X-ray fluorescence analysis. The emphasis is placed on the correction factor for matrix effects and its quantification. This correction factor is calculated using mathematical models proposed by Lachance-Traill, Claisse-Quintin and Rousseau, which can be applied in practice via an efficient calibration procedure. Each variable in these models is clearly identified so that specific numerical values can easily be substituted for calculation. This paper describes and emphasizes the application of the most effective existing models.

  15. Coulomb corrections to the parameters of the Landau-Pomeranchuk-Migdal effect theory

    NASA Astrophysics Data System (ADS)

    Voskresenskaya, O.; Kuraev, E.; Torosyan, H.

    2014-07-01

    Using the Coulomb correction to the screening angular parameter of the Molière multiple scattering theory we obtained analytically and numerically the Coulomb corrections to the quantities of the Migdal LPM effect theory. We showed that the Coulomb correction to the spectral bremsstrahlung rate allows one to eliminate the discrepancy between the predictions of the LPM effect theory and its measurement at least for high- Z targets and also to improve additionally the agreement between the predictions of the LPM effect theory analogue for a thin layer of matter and experimental data.

  16. The effect of background and illumination on color identification of real, 3D objects

    PubMed Central

    Allred, Sarah R.; Olkkonen, Maria

    2013-01-01

    For the surface reflectance of an object to be a useful cue to object identity, judgments of its color should remain stable across changes in the object's environment. In 2D scenes, there is general consensus that color judgments are much more stable across illumination changes than background changes. Here we investigate whether these findings generalize to real 3D objects. Observers made color matches to cubes as we independently varied both the illumination impinging on the cube and the 3D background of the cube. As in 2D scenes, we found relatively high but imperfect stability of color judgments under an illuminant shift. In contrast to 2D scenes, we found that background had little effect on average color judgments. In addition, variability of color judgments was increased by an illuminant shift and decreased by embedding the cube within a background. Taken together, these results suggest that in real 3D scenes with ample cues to object segregation, the addition of a background may improve stability of color identification. PMID:24273521

  17. Effect of different colored background lighting on LED discomfort glare perception

    NASA Astrophysics Data System (ADS)

    Sweater Hickcox, K.; Narendran, N.; Bullough, J. D.; Freyssinier, J. P.

    2012-10-01

    In the past decade, there has been increased interest in energy-efficient lighting as energy resources become higher in demand. Street lighting and outdoor lighting are applications that are rapidly changing from the incumbent high-pressure sodium (HPS) to newer technologies such as light-emitting diode (LED) or induction-type lamps. There is evidence that certain populations believe LED streetlights and area lights to produce more glare than HPS luminaires. A number of differences exist between new and traditional light sources besides efficiency. These include spectral power distribution (SPD), source luminance, beam intensity distribution, and the number of sources needed to achieve intended light levels. Many field studies and laboratory studies have shown a relationship between glare and SPD, with most studies suggesting that sources more weighted in short wavelengths have an increased likelihood of discomfort glare. A study to assess the effect of different SPDs on perception of discomfort glare was conducted. Subjects were shown a white-light LED array against a luminous background with one of three different SPDs (blue, white, or yellow). As well, different intensities of light from the array and from the background were used. For the range of conditions evaluated, the presence of any luminous background significantly reduced the perception of discomfort glare from the LED array. The blue background reduced perception significantly less than the white or the yellow backgrounds. The implications for solid-state lighting systems such as outdoor array lighting are discussed.

  18. Effects and detectability of quasi-single field inflation in the large-scale structure and cosmic microwave background

    SciTech Connect

    Sefusatti, Emiliano; Fergusson, James R.; Chen, Xingang; Shellard, E.P.S. E-mail: jf334@damtp.cam.ac.uk E-mail: E.P.S.Shellard@damtp.cam.ac.uk

    2012-08-01

    Quasi-single field inflation predicts a peculiar momentum dependence in the squeezed limit of the primordial bispectrum which smoothly interpolates between the local and equilateral models. This dependence is directly related to the mass of the isocurvatons in the theory which is determined by the supersymmetry. Therefore, in the event of detection of a non-zero primordial bispectrum, additional constraints on the parameter controlling the momentum-dependence in the squeezed limit becomes an important question. We explore the effects of these non-Gaussian initial conditions on large-scale structure and the cosmic microwave background, with particular attention to the galaxy power spectrum at large scales and scale-dependence corrections to galaxy bias. We determine the simultaneous constraints on the two parameters describing the QSF bispectrum that we can expect from upcoming large-scale structure and cosmic microwave background observations. We find that for relatively large values of the non-Gaussian amplitude parameters, but still well within current uncertainties, galaxy power spectrum measurements will be able to distinguish the QSF scenario from the predictions of the local model. A CMB likelihood analysis, as well as Fisher matrix analysis, shows that there is also a range of parameter values for which Planck data may be able distinguish between QSF models and the related local and equilateral shapes. Given the different observational weightings of the CMB and LSS results, degeneracies can be significantly reduced in a joint analysis.

  19. Effect of background plasma on electromagnetic properties of coaxial gyrotron cavity

    NASA Astrophysics Data System (ADS)

    Moskvitina, Yu. K.; Zaginaylov, G. I.; Tkachenko, V. I.

    2014-07-01

    We analyze the effect of the background plasma on the electromagnetic properties of coaxial resonators with a smooth and a corrugated inner conductors used in high-power gyrotrons. It is shown that the plasma produces different effects on the modes with different signs of the azimuthal index, leading to a decrease or an increase in the resonance frequencies. A modification of the distributions of electromagnetic fields and the electromagnetic energy density by the background plasma occurs in such a way that Ohmic losses decrease both on the inner and on the outer conductors. In the case of a smooth inner conductor, this is due to a decrease in the field strengths on the surface of the conductors. If the inner conductor is corrugated, the background plasma leads to an increase in the field strengths on its surface. Nevertheless, the relative Ohmic loss power decreases due to an increase in the energy density in the resonator (which is also caused by the background plasma). Calculations were mainly performed for a coaxial resonator of a gyrotron operating on the TE34.19 mode (Karlsruhe, Germany).

  20. Attention Drainage Effect: How Background Music Effects Concentration in Taiwanese College Students

    ERIC Educational Resources Information Center

    Chou, Peter Tze-Ming

    2010-01-01

    The purpose of this study was to see whether different types of background music affect the performance of a reading comprehension task in Taiwanese college students. There are two major research questions in this study. First, this study tries to find out whether listening to music affect the learner's concentration when they are doing a task…

  1. Attitude Certainty and Conflict Style: Divergent Effects of Correctness and Clarity.

    PubMed

    Rios, Kimberly; DeMarree, Kenneth G; Statzer, Johnathan

    2014-04-11

    Little research has examined the properties of people's attitudes that predict how they will respond to conflict with others whose opinions differ. We propose that one aspect of attitude certainty-attitude correctness, or the perception that one's attitude is the "right" attitude to have-will predict more competitive conflict styles. This hypothesis was tested across five data sets comprising four studies. In Studies 1a and 1b, perceptions of attitude correctness (but not another form of attitude certainty, attitude clarity) predicted participants' tendencies to send competitive messages to an ostensible partner who held the opposite opinion. In Studies 2 to 4, manipulations of attitude correctness, but not attitude clarity (Study 3), also increased competitiveness in conflict, and perceived correctness mediated the effect of the correctness manipulation on conflict style (Study 4). The present research has implications for both the predictors of conflict style and the consequences of different forms of attitude certainty. PMID:24727810

  2. Effects of higher-order aberration correction on stereopsis at different viewing durations

    NASA Astrophysics Data System (ADS)

    Kang, Jian; Xiao, Fei; Zhao, Junlei; Zhao, Haoxin; Hu, Yiyun; Tang, Guomao; Dai, Yun; Zhang, Yudong

    2015-07-01

    To better understand how the eye's optics affects stereopsis, we measured stereoacuity before and after higher-order aberration (HOA) correction with a binocular adaptive optics visual simulator. The HOAs were corrected either binocularly or monocularly in the better eye (the eye with better contrast sensitivity). A two-line stereo pattern served as the visual stimulus. Stereo thresholds at different viewing durations were obtained with the psychophysical method of constant stimuli. Binocular HOA correction led to significant improvement in stereoacuity. However, better eye HOA correction could bring either a bad degradation or a slight improvement in stereoacuity. As viewing duration increased, the stereo benefit approached the level of 1.0 for both binocular and better eye correction, suggesting that long viewing durations might weaken the effects of the eye's optical quality on stereopsis.

  3. Effects of higher-order aberration correction on stereopsis at different viewing durations.

    PubMed

    Kang, Jian; Xiao, Fei; Zhao, Junlei; Zhao, Haoxin; Hu, Yiyun; Tang, Guomao; Dai, Yun; Zhang, Yudong

    2015-07-01

    To better understand how the eye's optics affects stereopsis, we measured stereoacuity before and after higher-order aberration (HOA) correction with a binocular adaptive optics visual simulator. The HOAs were corrected either binocularly or monocularly in the better eye (the eye with better contrast sensitivity). A two-line stereo pattern served as the visual stimulus. Stereo thresholds at different viewing durations were obtained with the psychophysical method of constant stimuli. Binocular HOA correction led to significant improvement in stereoacuity. However, better eye HOA correction could bring either a bad degradation or a slight improvement in stereoacuity. As viewing duration increased, the stereo benefit approached the level of 1.0 for both binocular and better eye correction, suggesting that long viewing durations might weaken the effects of the eye's optical quality on stereopsis. PMID:26172611

  4. A simulation study of linear coupling effects and their correction in RHIC

    SciTech Connect

    Parzen, G.

    1992-11-01

    This paper describes a possible skew quadrupole correction system for linear coupling for the RHIC92 lattice. A simulation study has been done for the correction system. Results are given for the performance of the correction system, and the required strength of the skew quadruple correctors. An important effect of linear coupling in RHIC is to shift the tune {nu}{sub x} {nu}{sub y}, sometimes called tune splitting. Most of this tune splitting can be corrected with a two family skew quadrupole correction system. For RHIC92, the same 2 family correction system will work for all likely choices of {beta}*. This was not the case for the RHIC91 lattice where different families of correctors were needed for different {beta}*. The tune splitting described above which is corrected with a 2 family correction system is driven primarily by the {nu}{sub x} {minus} {nu}{sub y} harmonic of the skew quadrupole field given by the field multipole {alpha}l. There are several other effects of linear coupling present which are driven primarily by the {nu}{sub x} + {nu}{sub y} harmonics of the skew quadrupole field, {alpha}l. These include the following: (1) A higher order residual tune shift that remains after correction with the 2 family correction system. This tune shift is roughly quadratic in {alpha}l; (2) Possible large changes in the beta functions; (3) Possible increase in the beam size at injection due to the beta function distortion and the emittance distortion at injection.

  5. A simulation study of linear coupling effects and their correction in RHIC

    SciTech Connect

    Parzen, G.

    1992-11-01

    This paper describes a possible skew quadrupole correction system for linear coupling for the RHIC92 lattice. A simulation study has been done for the correction system. Results are given for the performance of the correction system, and the required strength of the skew quadruple correctors. An important effect of linear coupling in RHIC is to shift the tune [nu][sub x] [nu][sub y], sometimes called tune splitting. Most of this tune splitting can be corrected with a two family skew quadrupole correction system. For RHIC92, the same 2 family correction system will work for all likely choices of [beta]*. This was not the case for the RHIC91 lattice where different families of correctors were needed for different [beta]*. The tune splitting described above which is corrected with a 2 family correction system is driven primarily by the [nu][sub x] [minus] [nu][sub y] harmonic of the skew quadrupole field given by the field multipole [alpha]l. There are several other effects of linear coupling present which are driven primarily by the [nu][sub x] + [nu][sub y] harmonics of the skew quadrupole field, [alpha]l. These include the following: (1) A higher order residual tune shift that remains after correction with the 2 family correction system. This tune shift is roughly quadratic in [alpha]l; (2) Possible large changes in the beta functions; (3) Possible increase in the beam size at injection due to the beta function distortion and the emittance distortion at injection.

  6. The Effects of Postsecondary Correctional Education: "Final Report"

    ERIC Educational Resources Information Center

    Winterfield, Laura; Coggeshall, Mark; Burke-Storer, Michelle; Correa, Vanessa; Tidd, Simon

    2009-01-01

    The research presented in this report examines the effect of prison-based postsecondary education (PSE) on offenders both while incarcerated and after release. Urban Institute researchers worked with the staff of four institutions in three states to conduct inmate focus groups and stakeholder interviews to explore the motivations for enrolling in…

  7. Effect of background melt flow and interface distortion on the stability of Hall-Heroult cells

    NASA Astrophysics Data System (ADS)

    Sun, H.; Zikanov, O.; Finlayson, B. A.

    2005-09-01

    We use the method of linear stability analysis to study the effect of background melt flows and interface deformation on the stability characteristics of Hall-Heroult reduction cells. The linearized perturbation equations are based on a two-dimensional shallow water model. Two kinds of background states are investigated, one with a strong interface deformation and negligible melt flow, and another with strong vortical flows in aluminum and cryolite but a practically flat interface. It is found that the interface deformation with the length scale of the order of the cell size has a strong destabilizing effect. We also confirm earlier predictions that the unstable interfacial wave becomes wall-limited as the electromagnetic instability parameter increases. Tables 3, Figs 5, Refs 18.

  8. Effect of facility background gases on internal erosion of the 30-cm Hg ion thruster

    NASA Technical Reports Server (NTRS)

    Rawlin, V. K.; Mantenieks, M. A.

    1978-01-01

    Sputtering erosion of the upstream side of the molybdenum screen grid by discharge chamber ions in mercury bombardment thrusters was considered. Data which revealed that the screen grid erosion was very sensitive to the partial pressure of certain background gases in the space simulation vacuum facility were presented along with results of tests conducted to evaluate this effect. It is shown from estimates of the screen grid erosion in space that adequate lifetime for proposed missions exists.

  9. Effects of broiler breast meat thickness and background on color measurements.

    PubMed

    Bianchi, M; Fletcher, D L

    2002-11-01

    Experiments were conducted to determine the influence of broiler and turkey breast meat thickness and background on breast meat color measurements. Broiler breast fillets were sliced into two 1 cm thick slices and the turkey breast fillets into three 1 cm slices. Color values for lightness (L*), redness (a*), and yellowness (b*) were measured on the same top slice singly or while placed over the corresponding broiler and turkey slices. Color was measured in triplicate while the fillets were placed on the following backgrounds: plastic-coated white paper, white nylon, aluminum foil, black plastic, and a yellow commercial packaging tray (broiler only). Sample thickness significantly affected L*, a*, and b* values of turkey and chicken. Increased breast meat thickness resulted in lower L*, a*, and b5 values. Increased turkey meat thickness from 1 to 2 cm resulted in lower a* and b* values; however, only lower L* values were observed, with sample thickness increased from 1 to 3 cm. No differences in meat color were found when increasing turkey meat sample thickness from 2 to 3 cm. Background had a significant effect on single (1 cm) broiler and turkey meat color measurements but did not influence the color readings of the thicker multiple slice samples. These results indicate that the application of machine vision or in-line color measurement systems may have to take into account breast meat thickness, and in thinner samples, background color. PMID:12455607

  10. Effect of background trends removal on noise power spectrum measurements in digital x-ray imaging

    NASA Astrophysics Data System (ADS)

    Zhou, Zhongxing; Gao, Feng; Zhao, Huijuan; Zhang, Lixin

    2011-03-01

    Noise characterization through estimation of the noise power spectrum (NPS) is a central component of the evaluation of digital X-ray systems. Extensive works have been conducted to achieve accurate and precise measurement of NPS. One approach to improve the accuracy of the NPS measurement is to reduce the statistical variance of the NPS results. However, this method is based on the assumption that the noise in a radiographic image is arising from stochastic (random) processes. In the practical data, the artifactuals always superimpose on the stochastic noise as low-frequency background trends and prevent us from achieving accurate NPS. In this study, NPS measurement was implemented and compared before and after background trends removal, the results showed that background detrending reduced the variance of the low-frequency spectral components, hence improving the accuracy of NPS measurement. Our results also showed that involving more samples for ensemble averaging had little effect in reducing the variance of the low-frequency spectral components. All results implied that it is necessary and feasible to get better NPS estimate by appropriate background detredning.

  11. Computer program for pulsed thermocouples with corrections for radiation effects

    NASA Technical Reports Server (NTRS)

    Will, H. A.

    1981-01-01

    A pulsed thermocouple was used for measuring gas temperatures above the melting point of common thermocouples. This was done by allowing the thermocouple to heat until it approaches its melting point and then turning on the protective cooling gas. This method required a computer to extrapolate the thermocouple data to the higher gas temperatures. A method that includes the effect of radiation in the extrapolation is described. Computations of gas temperature are provided, along with the estimate of the final thermocouple wire temperature. Results from tests on high temperature combustor research rigs are presented.

  12. Study on modeling of resist heating effect correction in EB mask writer EBM-9000

    NASA Astrophysics Data System (ADS)

    Nomura, Haruyuki; Kamikubo, Takashi; Suganuma, Mizuna; Kato, Yasuo; Yashima, Jun; Nakayamada, Noriaki; Anze, Hirohito; Ogasawara, Munehiro

    2015-07-01

    Resist heating effect which is caused in electron beam lithography by rise in substrate temperature of a few tens or hundreds of degrees changes resist sensitivity and leads to degradation of local critical dimension uniformity (LCDU). Increasing writing pass count and reducing dose per pass is one way to avoid the resist heating effect, but it worsens writing throughput. As an alternative way, NuFlare Technology is developing a heating effect correction system which corrects CD deviation induced by resist heating effect and mitigates LCDU degradation even in high dose per pass conditions. Our developing correction model is based on a dose modulation method. Therefore, a kind of conversion equation to modify the dose corresponding to CD change by temperature rise is necessary. For this purpose, a CD variation model depending on local pattern density was introduced and its validity was confirmed by experiments and temperature simulations. And then the dose modulation rate which is a parameter to be used in the heating effect correction system was defined as ideally irrelevant to the local pattern density, and the actual values were also determined with the experimental results for several resist types. The accuracy of the heating effect correction was also discussed. Even when deviations depending on the pattern density slightly remains in the dose modulation rates (i.e., not ideal in actual), the estimated residual errors in the correction are sufficiently small and acceptable for practical 2 pass writing with the constant dose modulation rates. In these results, it is demonstrated that the CD variation model is effective for the heating effect correction system.

  13. [Preliminary evaluation of the effect of an attenuation correction method in myocardial perfusion SPECT].

    PubMed

    Cortés-Blanco, A; Fujii, C; Goris, M L

    1999-12-01

    We propose a method to assess an attenuation correction method in myocardial perfusion SPECT. Three types of images are obtained: one resulting from a classic acquisition and filtered back-projection (classic), and those resulting from acquisition with a transmission source and an iterative reconstruction, with (music) or without (hybrid) the attenuation correction factored in to compare the three types of images and classify them as normal or abnormal, a three dimensional inter-patient quantitative comparison method was used. Differences were computed as fractions of the myocardial volume in which density differences are significant by population standards. In 7 cases the cumulative difference between prone and supine in hybrid images was 124 and 45 in music images. In 10 cases the cumulative difference between classic vs music images was 279, and between classic and hybrid 86. The AC changed 4/12 cases from abnormal to normal. The attenuation correction effect was concentrated on the septal and inferior walls, but neither exclusively nor evenly among patients. The attenuation correction effectively minimizes attenuation effects by a factor of 2.7, due to a correction of at least 69%. The correction has a small but substantial effect on the results. PMID:10611567

  14. Cosmological Implications of the Effects of X-Ray Clusters on the Cosmic Microwave Background

    NASA Technical Reports Server (NTRS)

    Forman, William R.

    1996-01-01

    We have been carrying forward a program to confront X-ray observations of clusters and their evolution as derived from X-ray observatories with observations of the cosmic microwave background radiation (CMBR). In addition to the material covered in our previous reports (including three published papers), most recently we have explored the effects of a cosmological constant on the predicted Sunyaev-Zel'dovich effect from the ensemble of clusters. In this report we summarize that work from which a paper will be prepared.

  15. Effect of graded physical load on the state of the liver from morphometric data and biochemical blood indices of rats against a background of hypokinesia

    NASA Technical Reports Server (NTRS)

    Nikityuk, B. A.; Kogan, B. I.; Yermolyev, V. A.; Tindare, L. V.

    1980-01-01

    Tests were conducted on 100 sexually immature inbred August and Wistar male rats in order to determine the effects hypokinesia, physical load and phenamine on the liver. Weight and linear dimension fell in hypokinesia; total serum protein lowered and aldolase and cholesterol and beta-lipoprotein levels rose. Blood sugar content rose and liver glycogen fell. Interlinear differences of these indices are found. Rehabilitated physical loading against hypokinesia background diminished and at times completely prevented its negative effect. Extent of correction depended on animal species. Evidence of genotypical conditionality of organism adaptation to physical load in hypokinesia was found.

  16. Correction for nonlinear photon counting effects in lidar systems

    NASA Technical Reports Server (NTRS)

    Donovan, D. P.; Whiteway, J. A.; Carswell, A. I.

    1992-01-01

    Photomultiplier tubes (PMT's) employed in the photon counting (PC) mode of operation are widely used as detectors in lidar systems. In our laboratory, we have developed a versatile Nd:YAG lidar which is used for measurement of both the middle atmosphere and the troposphere. With this system, we encounter a very wide range of signal levels ranging from the extremely weak signals from the top of the mesosphere to the very strong returns from low level clouds. Although the system is capable of operating the PMT's in either the analog detection or photon counting mode, we find that often when we use photon counting we have portions of our lidar return which contain very useful information but are not within the linear operating regime of the PC system. We report the results of our efforts to explore the extent to which such high intensity PC signals can be quantitatively analyzed. In particular, a useful model relating the mean 'true' count rate and the observed count rate is presented and it's application to our system demonstrated. This model takes into account the variation in height of the PMT output pulses and the effect of the pulse height discrimination threshold.

  17. The Effect of Background Traffic Packet Size to VoIP Speech Quality

    NASA Astrophysics Data System (ADS)

    Triyason, Tuul; Kanthamanon, Prasert; Warasup, Kittipong; Yamsaengsung, Siam; Supattatham, Montri

    VoIP is gaining acceptance into the corporate world especially, in small and medium sized business that want to save cost for gaining advantage over their competitors. The good voice quality is one of challenging task in deployment plan because VoIP voice quality was affected by packet loss and jitter delay. In this paper, we study the effect of background traffic packet size to voice quality. The background traffic was generated by Bricks software and the speech quality was assessed by MOS. The obtained result shows an interesting relationship between the voice quality and the number of TCP packets and their size. With the same amount of data smaller packets affect the voice's quality more than the larger packet.

  18. Correction for partial volume effects in brain perfusion ECT imaging

    NASA Astrophysics Data System (ADS)

    Koole, Michel; Staelens, Steven; Van de Walle, Rik; Lemahieu, Ignace L.

    2003-05-01

    The accurate quantification of brain perfusion for emission computed tomography data (PET-SPECT) is limited by partial volume effects (PVE). This study presents a new approach to estimate accurately the true tissue tracer activity within the grey matter tissue compartment. The methodology is based on the availability of additional anatomical side information and on the assumption that activity concentration within the white matter tissue compartment is constant. Starting from an initial estimate for the white matter grey matter activity, the true tracer activity within the grey matter tissue compartment is estimated by an alternating ML-EM-algorithm. During the updating step the constant activity concentration within the white matter compartment is modelled in the forward projection in order to reconstruct the true activity distribution within the grey matter tissue compartment, hence reducing partial volume averaging. Consequently the estimate for the constant activity in the white matter tissue compartment is updated based on the new estimated activity distribution in the grey matter tissue compartment. We have tested this methodology by means of computer simulations. A T1-weighted MR brainscan of a patient was segmented into white matter, grey matter and cerebrospinal fluid, using the segmentation package of the SPM-software (Statistical Parametric Mapping). The segmented grey and white matter were used to simulate a SPECT acquisition, modelling the noise and the distance dependant detector response. Scatter and attenuation were ignored. Following the above described strategy, simulations have shown it is possible to reconstruct the true activity distribution for the grey matter tissue compartment (activity/tissue volume), assuming constant activity in the white matter tissue compartment.

  19. A novel approach to background subtraction in contrast-enhanced dual-energy digital mammography with commercially available mammography devices: Polychromaticity correction

    SciTech Connect

    Contillo, Adriano Di Domenico, Giovanni; Cardarelli, Paolo; Gambaccini, Mauro; Taibi, Angelo

    2015-11-15

    Purpose: Contrast-enhanced digital mammography is an image subtraction technique that is able to improve the detectability of lesions in dense breasts. One of the main sources of error, when the technique is performed by means of commercial mammography devices, is represented by the intrinsic polychromaticity of the x-ray beams. The aim of the work is to propose an iterative procedure, which only assumes the knowledge of a small set of universal quantities, to take into account the polychromaticity and correct the subtraction results accordingly. Methods: In order to verify the procedure, it has been applied to an analytical simulation of a target containing a contrast medium and to actual radiographs of a breast phantom containing cavities filled with a solution of the same medium. Results: The reconstructed densities of contrast medium were compared, showing very good agreement between the theoretical predictions and the experimental results already after the first iteration. Furthermore, the convergence of the iterative procedure was studied, showing that only a small number of iterations is necessary to reach limiting values. Conclusions: The proposed procedure represents an efficient solution to the polychromaticity issue, qualifying therefore as a viable alternative to inverse-map functions.

  20. The impact of accuracy motivation on interpretation, comparison, and correction processes: accuracy x knowledge accessibility effects.

    PubMed

    Stapel, D A; Koomen, W; Zeelenberg, M

    1998-04-01

    Four studies provide evidence for the notion that there may be boundaries to the extent to which accuracy motivation may help perceivers to escape the influence of fortuitously activated information. Specifically, although accuracy motivations may eliminate assimilative accessibility effects, they are less likely to eliminate contrastive accessibility effects. It was found that the occurrence of different types of contrast effects (comparison and correction) was not significantly affected by participants' accuracy motivations. Furthermore, it was found that the mechanisms instigated by accuracy motivations differ from those ignited by correction instructions: Accuracy motivations attenuate assimilation effects because perceivers add target interpretations to the one suggested by primed information. Conversely, it was found that correction instructions yield contrast and prompt respondents to remove the priming event's influence from their reaction to the target. PMID:9569650

  1. The Effects of an Exercise Program Consisting of Taekwondo Basic Movements on Posture Correction

    PubMed Central

    Byun, Sunghak; An, Changkyoo; Kim, Minho; Han, Dongwook

    2014-01-01

    [Purpose] The purpose of this study was to verify the effect of posture correctional programs using basic TaeKwonDo movements. [Subjects] The subjects were TaeKwonDo trainees attending an elementary school in B city. They were separated into experimental and control groups according to posture problems found during posture analysis. [Methods] The subjects of the training exercise program performed basic TaeKwonDo movements for 8 weeks, 3 times per week. The TaeKwonDo exercise program consisted of basic TaeKwonDo movements including Hwangso Makki, Meongye Chigi, Olgul Makki, Olgul Yop Makki, Batangson Arae Makki, Momtong An Makki and Apkubi. [Results] Hwangso Makki and Meongye Chigi movements had a significant positive effect on the correction of neck inclination. Olgul Makki, Olgul Yop Makki, Batangson Arae Makki and Momtong An Makki movements had beneficial effects on the correction of shoulder inclination. Apkubi movement had a significant beneficial effect on the correction of pelvis inclination. [Conclusion] This study demonstrated that an exercise program consisting of basic TaeKwonDo movements is an effective means of posture correction. PMID:25364119

  2. Effects of background color on GnRH and MCH levels in the barfin flounder brain.

    PubMed

    Amiya, Noriko; Amano, Masafumi; Yamanome, Takeshi; Yamamori, Kunio; Takahashi, Akiyoshi

    2008-01-01

    Effects of background color on gonadotropin-releasing hormone (GnRH) and melanin-concentrating hormone (MCH) levels in the brain of the barfin flounder Verasper moseri were monitored to investigate the interaction of GnRH and MCH in the brain. Fish were reared in white or black tanks from one month after hatching for about 7 months. MCH levels in the brain and pituitary were higher in the white tank fish. In contrast, chicken GnRH-II (cGnRH-II) levels in the brain were higher in the black tank fish. No significant differences between background colors were observed in the brain concerning salmon GnRH and seabream GnRH levels. Furthermore, six-month-old fish that had been reared in white tank were transferred to another white or black tank. Brain cGnRH-II levels were higher in black tank fish than those in white tank at 2 and 7 days after the transfer. Double-staining immunohistochemistry showed that some cGnRH-II-immunoreactive (ir) fibers were in close contact with MCH-ir cell bodies in the hypothalamus. These results indicate that background color affects not only MCH levels but also cGnRH-II levels in the brain and suggest that cGnRH-II may play a role in the regulation of MCH neural function, food intake, in the brain of the barfin flounder. PMID:17475262

  3. In vitro neurite guidance effects induced by polylysine pinstripe micropatterns with polylysine background.

    PubMed

    Joo, Sunghoon; Kang, Kyungtae; Nam, Yoonkey

    2015-08-01

    Engineered culture substrates with chemical neurite guidance cues have been used for studying the mechanism of axon pathfinding at cellular level. In this study, we designed a novel poly-l-lysine (PLL) micropattern ("pinstripe micropattern") to investigate how the same biomolecules with slightly different surface concentration can affect in vitro neuronal growth. The pinstripe micropattern was fabricated by stamping PLL on a PLL-coated glass coverslip, which resulted in denser PLL lines and a less-dense PLL background. There were two effects of the substrate on cultured primary hippocampal neuron: neurite initiation and growth cone turning. Although the whole surface was permissive for neurite outgrowth, we observed that the growth direction of neurites had a strong tendency to follow the stamped PLL line patterns with PLL background. However, the micropattern did not affect the spreading of cell body on the substrate. According to these investigations, we concluded that the PLL pinstripe pattern with PLL background, which had the step difference of polylysine concentrations, would be very useful for designing novel cell assays for the investigation of neurite guidance mechanisms, and suggested it as a new design method for controlling the direction of neurite growth on in vitro neural network. PMID:25630479

  4. Effect of Background Fluctuations on Kinetic Alfvén Wave Turbulence

    NASA Astrophysics Data System (ADS)

    Kumari, Anju; Sharma, R. P.

    2016-07-01

    The localization of Kinetic Alfvén wave (KAW) caused by finite amplitude background density fluctuations has been studied in intermediate beta plasma. The dynamical equations are derived taking into account the ponderomotive nonlinearity of the KAW as well as background density fluctuations and then studied numerically. Numerical simulation has been performed to analyze the effect of background density fluctuations on localized structures and resulting turbulent spectrum of KAW applicable to the magnetopause. Simulation results reveal that the power spectrum deviates from Kolmogorov scaling at the transverse size of KAW, equal to ion gyroradius. Steepening of the power spectrum at shorter wavelengths may be accountable for heating and acceleration of the plasma particles. Thus the presented coupling suggests a mechanism of energy transfer from larger length-scales to smaller length-scales. The relevance of present investigation with observations collected from the THEMIS spacecraft in magnetopause is also discussed [Chaston et al., 2008]. Reference Chaston, C., J. Bonnell, J. P. McFadden, C. W. Carlson, C. Cully, O. Le Contel A. Roux, H. U. Auster, K. H. Glassmeier, V. Angelopoulos, C. T. Russell (2008), Turbulent heating and cross-field transport near the magnetopause from THEMIS, Geophys. Res. Lett., 35, L17S08.

  5. Two-loop QCD corrections to the MSSM Higgs masses beyond the effective-potential approximation

    NASA Astrophysics Data System (ADS)

    Degrassi, G.; Di Vita, S.; Slavich, P.

    2015-02-01

    We compute the two-loop QCD corrections to the neutral Higgs-boson masses in the Minimal Supersymmetric Standard Model, including the effect of non-vanishing external momenta in the self-energies. We obtain corrections of and , i.e., all two-loop corrections that involve the strong gauge coupling when the only non-vanishing Yukawa coupling is the top one. We adopt either the renormalization scheme or a mixed on-shell (OS)- scheme where the top/stop parameters are renormalized on-shell. We compare our results with those of earlier calculations, pointing out an inconsistency in a recent result obtained in the mixed OS- scheme. The numerical impact of the new corrections on the prediction for the lightest-scalar mass is moderate, but already comparable to the accuracy of the Higgs-mass measurement at the Large Hadron Collider.

  6. One-loop effective potential of the Higgs field on the Schwarzschild background

    NASA Astrophysics Data System (ADS)

    Kazinski, P. O.

    2009-12-01

    A one-loop effective potential of the Higgs field on the Schwarzschild background is derived in the framework of a toy model: a SO(N) scalar multiplet interacting with the gauge fields, the SO(N) gauge symmetry being broken by the Higgs mechanism. As expected, the potential depends on the space point and results in a mass shift of all massive particles near a black hole. It is shown that the obtained potential is generally covariant, depends on the space point through the metric component g00 in the adapted coordinates, and has the same form for an arbitrary static, spherically symmetric background. Some properties of this potential are investigated. In particular, if the conformal symmetry holds valid for massless particles on the given background, there exist only two possible scenarios depending on the sign of an arbitrary constant arising from the regularization procedure: the masses of all massive particles grow infinitely, when they approach the black hole horizon, or the gauge symmetry is restored at a finite distance from the horizon and all particles become massless. If the conformal symmetry is spoiled, an additional term in the effective potential appears and the intermediate regime arises. Several normalization conditions fixing the undefined constants are proposed, and estimations for the mass shifts are given in these cases. It should be mentioned that the use of the one-loop approximation becomes questionable in the region where the one-loop effective potential acquires large values. So, in that region, we can believe in the obtained results only to a certain extent.

  7. Estimation of collective effective dose due to natural background radiation in Egypt

    NASA Astrophysics Data System (ADS)

    Henaish, B. A.; Tawfik, A. A.; Abu Zaid, H.; Gomaa, M. A.

    1994-07-01

    During the last few years, worldwide attention has been directed towards the estimation of natural background radiation levels. Several environmental monitoring networks have been established for systematic data collection and exchange of information.In the present study, measurements of annual effective dose from terrestrial γ-rays are carried out at pre-selected sites within several Egyptian governorates by using a calibrated gas-filled GM-detector connected to a microcomputer system. Contribution of the secondary cosmic-rays, which is of prime importance at sea level, is achieved by carrying out computation based on theoretical considerations.Terrestrial effective dose in Egypt is found to be between 106 and 371 μSv/yr, meanwhile the computed cosmic rays contribution is 260-296 μSv/yr. Accordingly, the annual collective effective dose due to natural background radiation is about 27,253 Man Sv for the last Egyptian population count (1989) considering 0.8 and 0.2 indoor and outdoor occupancy factors.

  8. Multiple effects of genetic background on variegated transgene expression in mice.

    PubMed Central

    Opsahl, Margaret L; McClenaghan, Margaret; Springbett, Anthea; Reid, Sarah; Lathe, Richard; Colman, Alan; Whitelaw, C Bruce A

    2002-01-01

    BLG/7 transgenic mice express an ovine beta-lactoglobulin transgene during lactation. Unusually, transgene expression levels in milk differ between siblings. This variable expression is due to variegated transgene expression in the mammary gland and is reminiscent of position-effect variegation. The BLG/7 line was created and maintained on a mixed CBA x C57BL/6 background. We have investigated the effect on transgene expression of backcrossing for 13 generations into these backgrounds. Variable transgene expression was observed in all populations examined, confirming that it is an inherent property of the transgene array at its site of integration. There were also strain-specific effects on transgene expression that appear to be independent of the inherent variegation. The transgene, compared to endogenous milk protein genes, is specifically susceptible to inbreeding depression. Outcrossing restored transgene expression levels to that of the parental population; thus suppression was not inherited. Finally, no generation-dependent decrease in mean expression levels was observed in the parental population. Thus, although the BLG/7 transgene is expressed in a variegated manner, there was no generation-associated accumulated silencing of transgene expression. PMID:11901126

  9. Array for Microwave Background Anisotropy: Observations, Data Analysis, and Results for Sunyaev-Zel'Dovich Effects

    NASA Astrophysics Data System (ADS)

    Wu, Jiun-Huei Proty; Ho, Paul T. P.; Huang, Chih-Wei Locutus; Koch, Patrick M.; Liao, Yu-Wei; Lin, Kai-Yang; Liu, Guo-Chin; Molnar, Sandor M.; Nishioka, Hiroaki; Umetsu, Keiichi; Wang, Fu-Cheng; Altamirano, Pablo; Birkinshaw, Mark; Chang, Chia-Hao; Chang, Shu-Hao; Chang, Su-Wei; Chen, Ming-Tang; Chiueh, Tzihong; Han, Chih-Chiang; Huang, Yau-De; Hwang, Yuh-Jing; Jiang, Homin; Kesteven, Michael; Kubo, Derek Y.; Lancaster, Katy; Li, Chao-Te; Martin-Cocher, Pierre; Oshiro, Peter; Raffin, Philippe; Wei, Tashun; Wilson, Warwick

    2009-04-01

    We present observations, analysis, and results for the first-year operation of Array for Microwave Background Anisotropy (AMiBA), an interferometric experiment designed to study cosmology via the measurement of cosmic microwave background (CMB). AMiBA is the first CMB interferometer operating at 3 mm to have reported successful results, currently with seven close-packed antennas of 60 cm diameter giving a synthesized resolution of around 6'. During 2007, AMiBA detected the Sunyaev-Zel'dovich effects (SZEs) of six galaxy clusters at redshift 0.091 <= z <= 0.322. An observing strategy with on-off-source switching is used to minimize the effects from electronic offset and ground pickup. Planets were used to test the observational capability of AMiBA and to calibrate the conversion from correlator time-lag data to visibilities. The detailed formalism for data analysis is given. We summarize our early tests including observations of planets and quasars, and present images, visibility profiles, the estimated central coordinates, sizes, and SZE amplitudes of the galaxy clusters. Scientific implications are summarized. We also discuss possible systematic effects in the results.

  10. The effect of background turbulence on the propagation of large-scale flames

    NASA Astrophysics Data System (ADS)

    Matalon, Moshe

    2008-12-01

    This paper is based on an invited presentation at the Conference on Turbulent Mixing and Beyond held in the Abdus Salam International Center for Theoretical Physics, Trieste, Italy (August 2007). It consists of a summary of recent investigations aimed at understanding the nature and consequences of the Darrieus-Landau instability that is prominent in premixed combustion. It describes rigorous asymptotic methodologies used to simplify the propagation problem of multi-dimensional and time-dependent premixed flames in order to understand the nonlinear evolution of hydrodynamically unstable flames. In particular, it addresses the effect of background turbulent noise on the structure and propagation of large-scale flames.

  11. Effects and Correction of Closed Orbit Magnet Errors in the SNS Ring

    SciTech Connect

    Bunch, S.C.; Holmes, J.

    2004-01-01

    We consider the effect and correction of three types of orbit errors in SNS: quadrupole displacement errors, dipole displacement errors, and dipole field errors. Using the ORBIT beam dynamics code, we focus on orbit deflection of a standard pencil beam and on beam losses in a high intensity injection simulation. We study the correction of these orbit errors using the proposed system of 88 (44 horizontal and 44 vertical) ring beam position monitors (BPMs) and 52 (24 horizontal and 28 vertical) dipole corrector magnets. Correction is carried out numerically by adjusting the kick strengths of the dipole corrector magnets to minimize the sum of the squares of the BPM signals for the pencil beam. In addition to using the exact BPM signals as input to the correction algorithm, we also consider the effect of random BPM signal errors. For all three types of error and for perturbations of individual magnets, the correction algorithm always chooses the three-bump method to localize the orbit displacement to the region between the magnet and its adjacent correctors. The values of the BPM signals resulting from specified settings of the dipole corrector kick strengths can be used to set up the orbit response matrix, which can then be applied to the correction in the limit that the signals from the separate errors add linearly. When high intensity calculations are carried out to study beam losses, it is seen that the SNS orbit correction system, even with BPM uncertainties, is sufficient to correct losses to less than 10-4 in nearly all cases, even those for which uncorrected losses constitute a large portion of the beam.

  12. The Effect of Knowledge of Correct Results per Item on Verbal Learning and Retention.

    ERIC Educational Resources Information Center

    De Klerk, Len F. W., Jr.; De Klerk, Len, Sr.

    1978-01-01

    Describes the methodology and results of an experiment to measure the effects of both overt and covert responses to educational stimuli with KCR (knowledge of correct results) feedback provided. Also compared are the effectiveness of both types of KCR-feedback in their ability to process and store the relevant information. (Author/RAO)

  13. The Short-Term Effects of Individual Corrective Feedback on L2 Pronunciation

    ERIC Educational Resources Information Center

    Dlaska, Andrea; Krekeler, Christian

    2013-01-01

    This article investigates the effect of explicit individual corrective feedback (ICF) on L2 pronunciation at the micro-level in order to determine whether ICF needs to complement listening only interventions. To this purpose, the authors carried out a study which investigated the immediate effect of feedback on comprehensibility of controlled…

  14. Bias Corrections for Standardized Effect Size Estimates Used with Single-Subject Experimental Designs

    ERIC Educational Resources Information Center

    Ugille, Maaike; Moeyaert, Mariola; Beretvas, S. Natasha; Ferron, John M.; Van den Noortgate, Wim

    2014-01-01

    A multilevel meta-analysis can combine the results of several single-subject experimental design studies. However, the estimated effects are biased if the effect sizes are standardized and the number of measurement occasions is small. In this study, the authors investigated 4 approaches to correct for this bias. First, the standardized effect…

  15. Direct and indirect methods for correcting the aerosol effect on remote sensing

    NASA Technical Reports Server (NTRS)

    Kaufman, Yoram J.; Tanre, Didier

    1994-01-01

    Aspects of aerosol studies and remote sensing are reviewed. Aerosol scatters solar radiation before it reaches the surface and scatters and absorbs it again after it is reflected from the surface and before it reaches the satellite sensor. The effect is spectrally and spatially dependent. Therefore atmospheric aerosol (dust, smoke and air pollution particles) has a significant effect on remote sensing. Correction for the aerosol effect was never achieved on an operational basis though several case studies were demonstrated. Correction can be done in a direct way by deriving the aerosol loading from the image itself and correcting for it using the appropriate radiative transfer model or by an indirect way, by defining remote sensing functions that are less dependent on the aerosol loading. To some degree this was already achieved in global remote sensing of vegetation where a composite of several days of NDVI (Normalized Difference Vegetation Index) measurements, choosing the maximal value, was used instead of a single cloud screened value. The Atmospheric Resistant Vegetation Index (ARVI) introduced recently for the NASA Earth Observing System EOS-MODIS is the most appropriate example of indirect correction, where the index is defined in such a way that the atmospheric effect in the blue spectral channel cancels to a large degree the atmospheric in the red channel in computations of a vegetation index. Atmospheric corrections can also use aerosol climatology and ground based instrumentation.

  16. [Correction Method of Atmospheric Scattering Effect Based on Three Spectrum Bands].

    PubMed

    Ye, Han-han; Wang, Xian-hua; Jiang, Xin-hua; Bu, Ting-ting

    2016-03-01

    As a major error of CO2 retrieval, atmospheric scattering effect hampers the application of satellite products. Effect of aerosol and combined effect of aerosol and ground surface are important source of atmospheric scattering, so it needs comprehensive consideration of scattering effect from aerosol and ground surface. Based on the continuum, strong and weak absorption part of three spectrum bands O2-A, CO2 1.6 μm and 2.06 μm, information of aerosol and albedo was analyzed, and improved full physics retrieval method was proposed, which can retrieve aerosol and albedo simultaneously to correct the scattering effect. Simulation study on CO2 error caused by aerosol and ground surface albedo CO2 error by correction method was carried out. CO2 error caused by aerosol optical depth and ground surface albedo can reach up to 8%, and CO2 error caused by different types of aerosol can reach up to 10%, while these two types of error can be controlled within 1% and 2% separately by this correction method, which shows that the method can correct the scattering effect effectively. Through evaluation of the results, the potential of this method for high precision satellite data retrieval is obvious, meanwhile, some problems which need to be noticed in real application were also pointed out. PMID:27400493

  17. The effects of background music on quality of sleep in elementary school children.

    PubMed

    Tan, Leepeng Patsy

    2004-01-01

    The purpose of this randomized controlled trial was to examine the effects of background music on quality of sleep in elementary school children. Convenience sampling was used to recruit a total of 86 fifth graders (43 boys and 43 girls) from an elementary school in a city in Taiwan. Subjects were randomly assigned to the experimental groups (n = 45) and the control group (n = 41). Subjects in the experimental group were given a 45-minute CD of music at naptime everyday and bedtime each night for 3 consecutive weeks. Sleep quality was measured using the Pittsburgh Sleep Quality Index (PSQI) at pretest and 3 weekly posttests. Repeated measures MANOVA was used to examine group differences across time. Results showed that subjects who received background music at naptime everyday and bedtime each night for 3 consecutive weeks had significant improvement in global sleep quality over time. Improvements were also observed in all 6 components of the PSQI although significant improvements were only observed in sleep duration and sleep efficiency. Some shortcomings of this study include the use of convenience sample, possibility of a Hawthorne effect, lack of objective measurements, and the use of non subject's preferred music. PMID:15307813

  18. Effect of sensor-target-background distance on target tracking using a fly eye sensor.

    PubMed

    Khan, Arif; Streeter, Robert W; Wright, Cameron H G; Barrett, Steven F; Frost, Susan A

    2014-01-01

    A multi-aperture optical sensor, known as a fly eye sensor, has been developed at the Wyoming Image and Signal Processing Research (WISPR) Laboratory based on the visual system of the common housefly Musca domestical. This biomimetic sensor shows promising edge detection capability, in varying contrast scenarios, with minimal processing overhead. Use of this sensor for fast motion detection, and object tracking is appealing, but optimizing the use of such a sensor requires detailed study. This paper analyzes the effect of placing the background at various distances greater than the target, and provides visualization of these example scenarios. A computer simulationof the sensor using MATLAB demonstrates that the placdementof a target closer to the sensor, and further from the background, affects the sensor response. If not properly considered, this may introduce ambiguities and degrade the performance of a tracking system based ont he flye eye sensor that requires precise location of the target in front of the sensor. This paper shows how a peroperly designed low-pass filter can greatly mitigate this effect with only a small degradation of the relative response magnitude at different distances from the sensor. PMID:25405451

  19. Correction of beam-beam effects in luminosity measurement in the forward region at CLIC

    NASA Astrophysics Data System (ADS)

    Lukić, S.; Božović-Jelisavčić, I.; Pandurović, M.; Smiljanić, I.

    2013-05-01

    Procedures for correcting the beam-beam effects in luminosity measurements at CLIC at 3 TeV center-of-mass energy are described and tested using Monte Carlo simulations. The angular counting loss due to the combined Beamstrahlung and initial-state radiation effects is corrected based on the reconstructed velocity of the collision frame of the Bhabha scattering. The distortion of the luminosity spectrum due to the initial-state radiation is corrected by deconvolution. At the end, the counting bias due to the finite calorimeter energy resolution is numerically corrected. To test the procedures, BHLUMI Bhabha event generator, and Guinea-Pig beam-beam simulation were used to generate the outgoing momenta of Bhabha particles in the bunch collisions at CLIC. The systematic effects of the beam-beam interaction on the luminosity measurement are corrected with precision of 1.4 permille in the upper 5% of the energy, and 2.7 permille in the range between 80 and 90% of the nominal center-of-mass energy.

  20. Gold price effect on stock market: A Markov switching vector error correction approach

    NASA Astrophysics Data System (ADS)

    Wai, Phoong Seuk; Ismail, Mohd Tahir; Kun, Sek Siok

    2014-06-01

    Gold is a popular precious metal where the demand is driven not only for practical use but also as a popular investments commodity. While stock market represents a country growth, thus gold price effect on stock market behavior as interest in the study. Markov Switching Vector Error Correction Models are applied to analysis the relationship between gold price and stock market changes since real financial data always exhibit regime switching, jumps or missing data through time. Besides, there are numerous specifications of Markov Switching Vector Error Correction Models and this paper will compare the intercept adjusted Markov Switching Vector Error Correction Model and intercept adjusted heteroskedasticity Markov Switching Vector Error Correction Model to determine the best model representation in capturing the transition of the time series. Results have shown that gold price has a positive relationship with Malaysia, Thailand and Indonesia stock market and a two regime intercept adjusted heteroskedasticity Markov Switching Vector Error Correction Model is able to provide the more significance and reliable result compare to intercept adjusted Markov Switching Vector Error Correction Models.

  1. Probing the effective number of neutrino species with the cosmic microwave background

    SciTech Connect

    Ichikawa, Kazuhide; Sekiguchi, Toyokazu; Takahashi, Tomo

    2008-10-15

    We discuss how much we can probe the effective number of neutrino species N{sub {nu}} with the cosmic microwave background alone. Using the data of the WMAP, ACBAR, CBI, and BOOMERANG experiments, we obtain a constraint on the effective number of neutrino species as 0.96

  2. Lifetime Effective Dose Assessment Based on Background Outdoor Gamma Exposure in Chihuahua City, Mexico

    PubMed Central

    Luevano-Gurrola, Sergio; Perez-Tapia, Angelica; Pinedo-Alvarez, Carmelo; Carrillo-Flores, Jorge; Montero-Cabrera, Maria Elena; Renteria-Villalobos, Marusia

    2015-01-01

    Determining ionizing radiation in a geographic area serves to assess its effects on a population’s health. The aim of this study was to evaluate the spatial distribution of the background environmental outdoor gamma dose rates in Chihuahua City. This study also estimated the annual effective dose and the lifetime cancer risks of the population of this city. To determine the outdoor gamma dose rate in air, the annual effective dose and the lifetime cancer risk, 48 sampling points were randomly selected in Chihuahua City. Outdoor gamma dose rate measurements were carried out by using a Geiger-Müller counter. Outdoor gamma dose rates ranged from 113 to 310 nGy·h−1. At the same sites, 48 soil samples were taken to obtain the activity concentrations of 226Ra, 232Th and 40K and to calculate their terrestrial gamma dose rates. Radioisotope activity concentrations were determined by gamma spectrometry. Calculated gamma dose rates ranged from 56 to 193 nGy·h−1. Results indicated that the lifetime effective dose of the inhabitants of Chihuahua City is on average 19.8 mSv, resulting in a lifetime cancer risk of 0.001. In addition, the mean of the activity concentrations in soil were 52, 73 and 1097 Bq·kg−1, for 226Ra, 232Th and 40K, respectively. From the analysis, the spatial distribution of 232Th, 226Ra and 40K is to the north, to the north-center and to the south of city, respectively. In conclusion, the natural background gamma dose received by the inhabitants of Chihuahua City is high and mainly due to the geological characteristics of the zone. From the radiological point of view, this kind of study allows us to identify the importance of manmade environments, which are often highly variable and difficult to characterize. PMID:26437425

  3. Lifetime Effective Dose Assessment Based on Background Outdoor Gamma Exposure in Chihuahua City, Mexico.

    PubMed

    Luevano-Gurrola, Sergio; Perez-Tapia, Angelica; Pinedo-Alvarez, Carmelo; Carrillo-Flores, Jorge; Montero-Cabrera, Maria Elena; Renteria-Villalobos, Marusia

    2015-10-01

    Determining ionizing radiation in a geographic area serves to assess its effects on a population's health. The aim of this study was to evaluate the spatial distribution of the background environmental outdoor gamma dose rates in Chihuahua City. This study also estimated the annual effective dose and the lifetime cancer risks of the population of this city. To determine the outdoor gamma dose rate in air, the annual effective dose and the lifetime cancer risk, 48 sampling points were randomly selected in Chihuahua City. Outdoor gamma dose rate measurements were carried out by using a Geiger-Müller counter. Outdoor gamma dose rates ranged from 113 to 310 nGy·h(-1). At the same sites, 48 soil samples were taken to obtain the activity concentrations of (226)Ra, (232)Th and (40)K and to calculate their terrestrial gamma dose rates. Radioisotope activity concentrations were determined by gamma spectrometry. Calculated gamma dose rates ranged from 56 to 193 nGy·h(-1). Results indicated that the lifetime effective dose of the inhabitants of Chihuahua City is on average 19.8 mSv, resulting in a lifetime cancer risk of 0.001. In addition, the mean of the activity concentrations in soil were 52, 73 and 1097 Bq·kg(-1), for (226)Ra, (232)Th and (40)K, respectively. From the analysis, the spatial distribution of (232)Th, (226)Ra and (40)K is to the north, to the north-center and to the south of city, respectively. In conclusion, the natural background gamma dose received by the inhabitants of Chihuahua City is high and mainly due to the geological characteristics of the zone. From the radiological point of view, this kind of study allows us to identify the importance of manmade environments, which are often highly variable and difficult to characterize. PMID:26437425

  4. Holographic s-wave condensation and Meissner-like effect in Gauss-Bonnet gravity with various non-linear corrections

    NASA Astrophysics Data System (ADS)

    Dey, Shirsendu; Lala, Arindam

    2015-03-01

    In this paper we have studied the onset of holographic s-wave condensate in the (4 + 1) dimensional planar Gauss-Bonnet-AdS black hole background with several non-linear corrections to the gauge field. In the probe limit, performing explicit analytic computations, with and without magnetic field, we found that these higher order corrections indeed affect various quantities characterizing the holographic superconductors. Also, performing a comparative study of the two non-linear electrodynamics it has been shown that the exponential electrodynamics has stronger effects on the formation of the scalar hair. We observe that our results agree well with those obtained numerically (Zhao et al., 2013).

  5. Effects of attenuation map accuracy on attenuation-corrected micro-SPECT images

    PubMed Central

    2013-01-01

    Background In single-photon emission computed tomography (SPECT), attenuation of photon flux in tissue affects quantitative accuracy of reconstructed images. Attenuation maps derived from X-ray computed tomography (CT) can be employed for attenuation correction. The attenuation coefficients as well as registration accuracy between SPECT and CT can be influenced by several factors. Here we investigate how such inaccuracies influence micro-SPECT quantification. Methods Effects of (1) misalignments between micro-SPECT and micro-CT through shifts and rotation, (2) globally altered attenuation coefficients and (3) combinations of these were evaluated. Tests were performed with a NEMA NU 4–2008 phantom and with rat cadavers containing sources with known activity. Results Changes in measured activities within volumes of interest in phantom images ranged from <1.5% (125I) and <0.6% (201Tl, 99mTc and 111In) for 1-mm shifts to <4.5% (125I) and <1.7% (201Tl, 99mTc and 111In) with large misregistration (3 mm). Changes induced by 15° rotation were smaller than those by 3-mm shifts. By significantly altering attenuation coefficients (±10%), activity changes of <5.2% for 125I and <2.7% for 201Tl, 99mTc and 111In were induced. Similar trends were seen in rat studies. Conclusions While getting sufficient accuracy of attenuation maps in clinical imaging is highly challenging, our results indicate that micro-SPECT quantification is quite robust to various imperfections of attenuation maps. PMID:23369630

  6. Method for correcting for isotope burn-in effects in fission neutron dosimeters

    DOEpatents

    Gold, Raymond; McElroy, William N.

    1988-01-01

    A method is described for correcting for effect of isotope burn-in in fission neutron dosimeters. Two quantities are measured in order to quantify the "burn-in" contribution, namely P.sub.Z',A', the amount of (Z', A') isotope that is burned-in, and F.sub.Z', A', the fissions per unit volume produced in the (Z', A') isotope. To measure P.sub.Z', A', two solid state track recorder fission deposits are prepared from the very same material that comprises the fission neutron dosimeter, and the mass and mass density are measured. One of these deposits is exposed along with the fission neutron dosimeter, whereas the second deposit is subsequently used for observation of background. P.sub.Z', A' is then determined by conducting a second irradiation, wherein both the irradiated and unirradiated fission deposits are used in solid state track recorder dosimeters for observation of the absolute number of fissions per unit volume. The difference between the latter determines P.sub.Z', A' since the thermal neutron cross section is known. F.sub.Z', A' is obtained by using a fission neutron dosimeter for this specific isotope, which is exposed along with the original threshold fission neutron dosimeter to experience the same neutron flux-time history at the same location. In order to determine the fissions per unit volume produced in the isotope (Z', A') as it ingrows during the irradiation, B.sub.Z', A', from these observations, the neutron field must generally be either time independent or a separable function of time t and neutron energy E.

  7. Te Inclusions in CZT Detectors: New Method for Correcting Their Adverse Effects

    SciTech Connect

    Bolotnikov, A.E.; Babalola, S.; Camarda, G.S.; Cui, Y.; Egarievwe, S.U.; Hawrami, R.; Hossain, A.; Yang, G.; James, R.B.

    2009-10-25

    Both Te inclusions and point defects can trap the charge carriers generated by ionizing particles in CdZnTe (CZT) detectors. The amount of charge trapped by point defects is proportional to the carriers’ drift time and can be corrected electronically. In the case of Te inclusions, the charge loss depends upon their random locations with respect to the electron cloud. Consequently, inclusions introduce fluctuations in the charge signals, which cannot be easily corrected. In this paper, we describe direct measurements of the cumulative effect of Te inclusions and its influence on the response of CZT detectors of different thicknesses and different sizes and concentrations of Te inclusions. We also discuss a means of partially correcting their adverse effects.

  8. The corrections for significant wave height and attitude effects in the TOPEX radar altimeter

    NASA Astrophysics Data System (ADS)

    Hayne, G. S.; Hancock, D. W.; Purdy, C. L.; Callahan, P. S.

    1994-12-01

    The routine ground processing of data from the NASA radar altimeter of TOPEX/POSEIDON includes instrument corrections for the effects of significant wave height and attitude angle changes on the altimeter's estimates of range, backscattered power, and significant wave height. This paper describes how these instrument corrections were generated and how they are applied. Detailed waveform fitting to telemetered waveform samples is use to assess the effectiveness of the corrections. There are several altimeter hardware-caused small waveform departures from the model waveforms and these departures, designated waveform 'features', are described in detailed. A consequence of the waveform features, and their positioning relationship to range rate, is that range data for ground tracks moving toward the equator may differ systematically by about a centimeter compared to range data for ground tracks moving away from the equator. The results and discussion are limited to side A of the redundant altimeter, as only side A has been operated on orbit.

  9. Written Corrective Feedback: Effects of Focused and Unfocused Grammar Correction on the Case Acquisition in L2 German

    ERIC Educational Resources Information Center

    Sun, Sonja Huiying

    2013-01-01

    Thirty-three students of fourth semester German at the University of Kansas participated in the study which sought to investigate whether focused written corrective feedback (WCF) promoted the acquisition of the German case morphology over the course of a semester. Participants received teacher WCF on five two-draft essay assignments under three…

  10. Effect of Parental Migration Background on Childhood Nutrition, Physical Activity, and Body Mass Index

    PubMed Central

    Bottai, Matteo; Kull, Inger; Wickman, Magnus; Wolk, Alicja; Moradi, Tahereh

    2014-01-01

    Background. Poor nutrition, lack of physical activity, and obesity in children have important public health implications but, to date, their effects have not been studied in the growing population of children in Sweden with immigrant parents. Methods. We estimated the association between parental migration background and nutrition, physical activity, and weight in 8-year-old children born in Stockholm between 1994 and 1996 of immigrants and Swedish parents (n = 2589). Data were collected through clinical examination and questionnaires filled out by parents. Odds ratios (ORs) and 95% confidence intervals (95% CIs) were calculated using multivariable logistic regression. Results. Children of immigrants complied more closely with Nordic Nutrition Recommendations compared with those of Swedes (OR = 1.35, 95% CI 1.11–1.64). They had higher intake of dietary fibre, vitamins C, B6, and E, folic acid, and polyunsaturated fatty acids (omega-3 and omega-6) reflecting higher consumption of foods of plant origin, but lower intake of vitamins A and D, calcium, and iron reflecting lower consumption of dairy products. Children of immigrants had higher intake of sucrose reflecting higher consumption of sugar and sweets. Furthermore, these children had a higher risk of having low physical activity (OR = 1.31, 95% CI 1.06–1.62) and being overweight (OR = 1.33, 95% CI 1.06–1.65) compared with children of Swedish parents. The odds of having low physical activity and being overweight were even higher in children whose parents were both immigrants. A low level of parental education was associated with increased risk of low physical activity regardless of immigration background. Conclusions. Culturally appropriate tools to capture the diverse range of ethnic foods and other lifestyle habits are needed. Healthcare professionals should be aware of the low levels of physical activity, increased weight, and lack of consumption of some important vitamins among children of immigrants

  11. Effect of Full Correction Versus Partial Correction of Elevated Blood Glucose in the Emergency Department on Hospital Length of Stay.

    PubMed

    Johnson-Clague, Michaela; DiLeo, Jessica; Katz, Michael D; Patanwala, Asad E

    2016-01-01

    There is limited information to guide the extent to which asymptomatic hyperglycemia needs to be corrected in patients presenting to the emergency department (ED) with unrelated complaints. The objective of this study was to compare full correction (FC) versus partial correction (PC) of elevated blood glucose in the ED on hospital length of stay. This was a retrospective cohort study conducted in an academic ED in the United States. Adult diabetic patients with hyperglycemia (blood glucose >200 mg/dL) in the ED who were treated with subcutaneous insulin were included. Patients were categorized based on the level of blood glucose control achieved within the first 24 hours from triage: (1) FC group for whom blood glucose <200 mg/dL was achieved or (2) PC group for whom blood glucose remained ≥200 mg/dL. The primary outcome measure was a comparison of hospital length of stay between groups. A total of 161 patients were included in this study (FC = 81, PC = 80). There was no significant difference between hospital length of stay in the FC [3 days (interquartile range, 1-5 days)] and PC [3 days (interquartile range, 2-6 days)] groups (P = 0.159). In the multivariate analysis, after adjusting for potential confounders, there was no significant association between level of correction and hospital length of stay (log-transformed) (coefficient 0.238; 95% confidence interval, -0.062 to 0.537; P = 0.119; R = 13%). The extent of glucose correction was not associated with a decrease in hospital length of stay in diabetic patients with hyperglycemia in the ED. PMID:25187094

  12. Effect of correction of aberration dynamics on chaos in human ocular accommodation.

    PubMed

    Hampson, Karen M; Cufflin, Matthew P; Mallen, Edward A H

    2013-11-15

    We used adaptive optics to determine the effect of monochromatic aberration dynamics on the level of chaos in the accommodation control system. Four participants viewed a stationary target while the dynamics of their aberrations were either left uncorrected, defocus was corrected, or all aberrations except defocus were corrected. Chaos theory analysis was used to discern changes in the accommodative microfluctuations. We found a statistically significant reduction in the chaotic nature of the accommodation microfluctuations during correction of defocus, but not when all aberrations except defocus were corrected. The Lyapunov exponent decreased from 0.71 ± 0.07 D/s (baseline) to 0.55 ± 0.03 D/s (correction of defocus fluctuations). As the reduction of chaos in physiological signals is indicative of stress to the system, the results indicate that for the participants included in this study, fluctuations in defocus have a more profound effect than those of the other aberrations. There were no changes in the power spectrum between experimental conditions. Hence chaos theory analysis is a more subtle marker of changes in the accommodation control system and will be of value in the study of myopia onset and progression. PMID:24322122

  13. Viscous effects on the Rayleigh-Taylor instability with background temperature gradient

    DOE PAGESBeta

    Gerashchenko, Sergiy; Livescu, Daniel

    2016-07-28

    Here we studied the growth rate of the compressible Rayleigh-Taylor instability in the presence of a background temperature gradient, Θ, using a normal mode analysis. The effect of Θ variation is examined for three interface types corresponding to the combinations of the viscous properties of the fluids (inviscid-inviscid, viscous-viscous, and viscous-inviscid) at different Atwood numbers, At, and when at least one of the fluids' viscosity is non-zero, as a function of the Grashof number. For the general case, the resulting ordinary differential equations are solved numerically; however, dispersion relations for the growth rate are presented for several limiting cases. Anmore » analytical solution is found for the inviscid-inviscid interface and the corresponding dispersion equation for the growth rate is obtained in the limit of large Θ. For the viscous-inviscid case, a dispersion relation is derived in the incompressible limit and Θ=0. Compared to Θ=0 case, the role of Θ<0 (hotter light fluid) is destabilizing and becomes stabilizing when Θ>0 (colder light fluid). The most pronounced effect of Θ ≠ 0 is found at low At and/or at large perturbation wavelengths relative to the domain size for all interface types. On the other hand, at small perturbation wavelengths relative to the domain size, the growth rate for the Θ<0 case exceeds the infinite domain incompressible constant density result. The results are applied to two practical examples, using sets of parameters relevant to Inertial Confinement Fusion coasting stage and solar corona plumes. The role of viscosity on the growth rate reduction is discussed together with highlighting the range of wavenumbers most affected by viscosity. The viscous effects further increase in the presence of background temperature gradient, when the viscosity is temperature dependent.« less

  14. Identification of galaxy clusters in cosmic microwave background maps using the Sunyaev-Zel'dovich effect

    NASA Astrophysics Data System (ADS)

    Novaes, C. P.; Wuensche, C. A.

    2012-09-01

    Context. The Planck satellite was launched in 2009 by the European Space Agency to study the properties of the cosmic microwave background (CMB). An expected result of the Planck data analysis is the distinction of the various contaminants of the CMB signal. Among these contaminants is the Sunyaev-Zel'dovich (SZ) effect, which is caused by the inverse Compton scattering of CMB photons by high energy electrons in the intracluster medium of galaxy clusters. Aims: We modify a public version of the JADE (Joint Approximate Diagonalization of Eigenmatrices) algorithm, to deal with noisy data, and then use this algorithm as a tool to search for SZ clusters in two simulated datasets. Methods: The first dataset is composed of simple "homemade" simulations and the second of full sky simulations of high angular resolution, available at the LAMBDA (Legacy Archive for Microwave Background Data Analysis) website. The process of component separation can be summarized in four main steps: (1) pre-processing based on wavelet analysis, which performs an initial cleaning (denoising) of data to minimize the noise level; (2) the separation of the components (emissions) by JADE; (3) the calibration of the recovered SZ map; and (4) the identification of the positions and intensities of the clusters using the SExtractor software. Results: The results show that our JADE-based algorithm is effective in identifying the position and intensity of the SZ clusters, with the purities being higher then 90% for the extracted "catalogues". This value changes slightly according to the characteristics of noise and the number of components included in the input maps. Conclusions: The main highlight of our developed work is the effective recovery rate of SZ sources from noisy data, with no a priori assumptions. This powerful algorithm can be easily implemented and become an interesting complementary option to the "matched filter" algorithm (hereafter MF) widely used in SZ data analysis.

  15. Viscous effects on the Rayleigh-Taylor instability with background temperature gradient

    NASA Astrophysics Data System (ADS)

    Gerashchenko, S.; Livescu, D.

    2016-07-01

    The growth rate of the compressible Rayleigh-Taylor instability is studied in the presence of a background temperature gradient, Θ, using a normal mode analysis. The effect of Θ variation is examined for three interface types corresponding to the combinations of the viscous properties of the fluids (inviscid-inviscid, viscous-viscous, and viscous-inviscid) at different Atwood numbers, At, and when at least one of the fluids' viscosity is non-zero, as a function of the Grashof number. For the general case, the resulting ordinary differential equations are solved numerically; however, dispersion relations for the growth rate are presented for several limiting cases. An analytical solution is found for the inviscid-inviscid interface and the corresponding dispersion equation for the growth rate is obtained in the limit of large Θ. For the viscous-inviscid case, a dispersion relation is derived in the incompressible limit and Θ = 0. Compared to Θ = 0 case, the role of Θ < 0 (hotter light fluid) is destabilizing and becomes stabilizing when Θ > 0 (colder light fluid). The most pronounced effect of Θ ≠ 0 is found at low At and/or at large perturbation wavelengths relative to the domain size for all interface types. On the other hand, at small perturbation wavelengths relative to the domain size, the growth rate for the Θ < 0 case exceeds the infinite domain incompressible constant density result. The results are applied to two practical examples, using sets of parameters relevant to Inertial Confinement Fusion coasting stage and solar corona plumes. The role of viscosity on the growth rate reduction is discussed together with highlighting the range of wavenumbers most affected by viscosity. The viscous effects further increase in the presence of background temperature gradient, when the viscosity is temperature dependent.

  16. Stabilizing effect of ionized background of trans-Alfvenic expansion of exploding plasmas

    SciTech Connect

    Zakharov, Yu.P.; Ponomarenko, A.G.; Dudnikova, G.I.; Vshivkov, V.A.

    1995-12-31

    Recently a lot of theoretical and numerical calculations have been performed devoted to the study of Large-Larmor-Flute Instability (LLFI). Such instability was discovered initially in laboratory and later in active experiments (AMPTE, CRRES) on expansion of a quasispherical plasma cloud in a ``vacuum`` magnetic field {rvec B}{sub 0}. In the laser-produced plasma experiments at KI-1 facility it was established for the first time, that such non-MHD instability and LHD-instability of skin-layer may effectively be suppressed by ionized background at high-Alfven Mach numbers M{sub A} {much_gt} 1 as well as in a transient regime M{sub A} {approximately} 1. In the present paper on the basis of laboratory and computer simulation the value of M{sub A} was defined more exactly and other similarity parameters characterizing the development of LLFI was founded. The laser experiments were realized in hydrogen and argon background plasmas. The computer simulations were carried out with 2D electromagnetic hybrid code. It was exposed the transition from flute increase to decrease one when M{sub A} changed from M{sub A} = 1 to M{sub A} = 3.

  17. The effects of fundamental frequency contour manipulations on speech intelligibility in background noise.

    PubMed

    Miller, Sharon E; Schlauch, Robert S; Watson, Peter J

    2010-07-01

    Previous studies have documented that speech with flattened or inverted fundamental frequency (F0) contours is less intelligible than speech with natural variations in F0. The purpose of this present study was to further investigate how F0 manipulations affect speech intelligibility in background noise. Speech recognition in noise was measured for sentences having the following F0 contours: unmodified, flattened at the median, natural but exaggerated, inverted, and sinusoidally frequency modulated at rates of 2.5 and 5.0 Hz, rates shown to make vowels more perceptually salient in background noise. Five talkers produced 180 stimulus sentences, with 30 unique sentences per F0 contour condition. Flattening or exaggerating the F0 contour reduced key word recognition performance by 13% relative to the naturally produced speech. Inverting or sinusoidally frequency modulating the F0 contour reduced performance by 23% relative to typically produced speech. These results support the notion that linguistically incorrect or misleading cues have a greater deleterious effect on speech understanding than linguistically neutral cues. PMID:20649237

  18. Mutualism effectiveness and vertical transmission of symbiotic fungal endophytes in response to host genetic background

    PubMed Central

    Gundel, Pedro E; Martínez-Ghersa, María A; Omacini, Marina; Cuyeu, Romina; Pagano, Elba; Ríos, Raúl; Ghersa, Claudio M

    2012-01-01

    Certain species of the Pooideae subfamily develop stress tolerance and herbivory resistance through symbiosis with vertically transmitted, asexual fungi. This symbiosis is specific, and genetic factors modulate the compatibility between partners. Although gene flow is clearly a fitness trait in allogamous grasses, because it injects hybrid vigor and raw material for evolution, it could reduce compatibility and thus mutualism effectiveness. To explore the importance of host genetic background in modulating the performance of symbiosis, Lolium multiflorum plants, infected and noninfected with Neotyphodium occultans, were crossed with genetically distant plants of isolines (susceptible and resistant to diclofop-methyl herbicide) bred from two cultivars and exposed to stress. The endophyte improved seedling survival in genotypes susceptible to herbicide, while it had a negative effect on one of the genetically resistant crosses. Mutualism provided resistance to herbivory independently of the host genotype, but this effect vanished under stress. While no endophyte effect was observed on host reproductive success, it was increased by interpopulation plant crosses. Neither gene flow nor herbicide had an important impact on endophyte transmission. Host fitness improvements attributable to gene flow do not appear to result in direct conflict with mutualism while this seems to be an important mechanism for the ecological and contemporary evolution of the symbiotum. PMID:23346228

  19. [Correction of erectile dysfunction in patients with benign prostate hyperplasia using daily administration of tadalafil 5 mg against the background of combined drug therapy].

    PubMed

    Volkov, A A; Petrichko, M I; Budnik, N V

    2013-01-01

    The study included 59 patients with benign prostate hyperplasia (BPH) and erectile dysfunction (ED), inhibited inflammation in the prostate gland and with normal or medically normalized levels of total testosterone. All the patients underwent conservative therapy using dutasteride and tamsulosin, 21 of them (group 2) additionally received tadalafil 5 mg daily. Efficacy of treatment was assessed by self-assessment questionnaire of patients before treatment and 12 weeks after therapy. In group 1 of patients, the dynamics of the erectile function, sexual satisfaction and quality of life for patients was not revealed. In the group 2, improvement in erectile function in an average of 19 points was shown (IIEF-5 questionnaire). According to the AMS questionnaire, improvement in sexual function was demonstrated; in patients with compensated androgen deficiency, however, response to the treatment with tadalafil was less pronounced. According to BSFI score after 3 months of therapy with tadalafil, indicator of overall satisfaction of sexual life improved to 2.4 points (p < 0.002). According to the Hospital Anxiety and Depression Scale, anxiety in patients was reduced to the permissible values (p < 0.0002), the level of depression was decreased by almost 2-fold (p < 0.0002). The total IPSS score decreased from 13 to 9 points in average. The inclusion of tadalafil in complex of combined conservative therapy of patients with BPH not only improves sexual function but has a positive effect on symptoms of the disease and the psychological state of the patient. PMID:24437241

  20. Estimating leaf chlorophyll of barley at different growth stages using spectral indices to reduce soil background and canopy structure effects

    NASA Astrophysics Data System (ADS)

    Yu, Kang; Lenz-Wiedemann, Victoria; Chen, Xinping; Bareth, Georg

    2014-11-01

    Monitoring in situ chlorophyll (Chl) content in agricultural crop leaves is of great importance for stress detection, nutritional state diagnosis, yield prediction and studying the mechanisms of plant and environment interaction. Numerous spectral indices have been developed for chlorophyll estimation from leaf- and canopy-level reflectance. However, in most cases, these indices are negatively affected by variations in canopy structure and soil background. The objective of this study was to develop spectral indices that can reduce the effects of varied canopy structure and growth stages for the estimation of leaf Chl. Hyperspectral reflectance data was obtained through simulation by a radiative transfer model, PROSAIL, and measurements from canopies of barley comprising different cultivars across growth stages using spectroradiometers. We applied a comprehensive band-optimization algorithm to explore five types of spectral indices: reflectance difference (RD), reflectance ratio (RR), normalized reflectance difference (NRD), difference of reflectance ratio (DRR) and ratio of reflectance difference (RRD). Indirectly using the multiple scatter correction (MSC) theory, we hypothesized that RRD can eliminate adverse effects of soil background, canopy structure and multiple scattering. Published indices and multivariate models such as optimum multiple band regression (OMBR), partial least squares regression (PLSR) and support vector machines for regression (SVR) were also employed. Results showed that the ratio of reflectance difference index (RRDI) optimized for simulated data significantly improved the correlation with Chl (R2 = 0.98, p < 0.0001) and was insensitive to LAI variations (1-8), compared to widely used indices such as MCARI/OSAVI (R2 = 0.64, p < 0.0001) and TCARI/OSAVI (R2 = 0.74, p < 0.0001). The RRDI optimized for barley explained 76% of the variation in Chl and outperformed multivariate models. However, the accuracy decreased when employing the indices

  1. Effects of a traffic noise background on judgements of aircraft noise

    NASA Technical Reports Server (NTRS)

    Powell, C. A.; Rice, C. G.

    1974-01-01

    A study was conducted in which subjects judged aircraft noises in the presence of road traffic background noise. Two different techniques for presenting the background noises were evaluated. For one technique, the background noise was continuous over the whole of a test session. For the other, the background noise was changed with each aircraft noise. A range of aircraft noise levels and traffic noise levels were presented to simulate typical indoor levels.

  2. Evaluating the Effectiveness of the National Institute of Corrections' "Thinking for a Change" Program among Probationers

    ERIC Educational Resources Information Center

    Golden, Lori Suzanne; Gatchel, Robert J.; Cahill, Melissa Anne

    2006-01-01

    This study evaluated the effectiveness of a National Institute of Corrections' cognitive-behavioral program for adult offenders, entitled "Thinking for a Change." One hundred male and 42 female probationers were studied. Probationers assigned to the "Thinking for a Change" program were matched with a comparison group not assigned to the program…

  3. The Effectiveness of Corrective Feedback in SLA: A Meta-Analysis

    ERIC Educational Resources Information Center

    Li, Shaofeng

    2010-01-01

    This study reports on a meta-analysis on the effectiveness of corrective feedback in second language acquisition. By establishing a different set of inclusion/exclusion criteria than previous meta-analyses and performing a series of methodological moves, it is intended to be an update and complement to previous meta-analyses. Altogether 33 primary…

  4. The Relative Effects of Explicit Correction and Recasts on Two Target Structures via Two Communication Modes

    ERIC Educational Resources Information Center

    Yilmaz, Yucel

    2012-01-01

    This study investigated the effects of negative feedback type (i.e., explicit correction vs. recasts), communication mode (i.e., face-to-face communication vs. synchronous computer-mediated communication), and target structure salience (i.e., salient vs. nonsalient) on the acquisition of two Turkish morphemes. Forty-eight native speakers of…

  5. The Effectiveness of Written Corrective Feedback and the Impact Lao Learners' Beliefs Have on Uptake

    ERIC Educational Resources Information Center

    Rummel, Stephanie; Bitchener, John

    2015-01-01

    This article presents the results of a study examining the effectiveness of written corrective feedback (CF) on the simple past tense and the impact beliefs may have on students' uptake of the feedback they receive. A seven-week study was carried out with 42 advanced EFL learners in Vientiane, Laos. Students' beliefs about written CF were first…

  6. The Noticeability and Effectiveness of Corrective Feedback in Relation to Target Type

    ERIC Educational Resources Information Center

    Kartchava, Eva; Ammar, Ahlem

    2014-01-01

    This quasi-experimental study investigated the noticeability and effectiveness of three corrective feedback (CF) techniques (recasts, prompts and a combination of the two) delivered in the language classroom. The participants were four groups of high-beginner college level francophone learners of English as a second language (ESL) (n = 99) and…

  7. "Effect of Anxiety Reduction on Children's School Performance and Social Adjustment": Correction to Wood (2006)

    ERIC Educational Resources Information Center

    Wood, Jeffrey J.

    2007-01-01

    Reports an error in "Effect of anxiety reduction on children's school performance and social adjustment" by Jeffrey Wood (Developmental Psychology, 2006[Mar], Vol 42[2], 345-349). The byline and author note should have included the author's middle initial, J. Thus, the byline and author note should refer to "Jeffrey J. Wood." The correction is…

  8. Effects of Length, Complexity, and Grammatical Correctness on Stuttering in Spanish-Speaking Preschool Children

    ERIC Educational Resources Information Center

    Watson, Jennifer B.; Byrd, Courtney T.; Carlo, Edna J.

    2011-01-01

    Purpose: To explore the effects of utterance length, syntactic complexity, and grammatical correctness on stuttering in the spontaneous speech of young, monolingual Spanish-speaking children. Method: Spontaneous speech samples of 11 monolingual Spanish-speaking children who stuttered, ages 35 to 70 months, were examined. Mean number of syllables,…

  9. The Effects of the Timing of Corrective Feedback on the Acquisition of a New Linguistic Structure

    ERIC Educational Resources Information Center

    Li, Shaofeng; Zhu, Yan; Ellis, Rod

    2016-01-01

    The article reports on a study investigating the comparative effects of immediate and delayed corrective feedback in learning the English past passive construction, a linguistic structure of which the learners had little prior knowledge. A total of 120 learners of English as a foreign language (EFL) from 4 intact classes at a Chinese middle school…

  10. The effect of finite Larmor radius corrections on Jeans instability of quantum plasma

    SciTech Connect

    Sharma, Prerana; Chhajlani, R. K.

    2013-09-15

    The influence of finite Larmor radius (FLR) effects on the Jeans instability of infinitely conducting homogeneous quantum plasma is investigated. The quantum magnetohydrodynamic (QMHD) model is used to formulate the problem. The contribution of FLR is incorporated to the QMHD set of equations in the present analysis. The general dispersion relation is obtained analytically using the normal mode analysis technique which is modified due to the contribution of FLR corrections. From general dispersion relation, the condition of instability is obtained and it is found that Jeans condition is modified due to quantum effect. The general dispersion relation is reduced for both transverse and longitudinal mode of propagations. The condition of gravitational instability is modified due to the presence of both FLR and quantum corrections in the transverse mode of propagation. In longitudinal case, it is found to be unaffected by the FLR effects but modified due to the quantum corrections. The growth rate of Jeans instability is discussed numerically for various values of quantum and FLR corrections of the medium. It is found that the quantum parameter and FLR effects have stabilizing influence on the growth rate of instability of the system.

  11. Evaluating Statistical Significance Using Corrected and Uncorrected Magnitude of Effect Size Estimates.

    ERIC Educational Resources Information Center

    Snyder, Patricia; Lawson, Stephen

    Magnitude of effect measures (MEMs), when adequately understood and correctly used, are important aids for researchers who do not want to rely solely on tests of statistical significance in substantive result interpretation. The MEM tells how much of the dependent variable can be controlled, predicted, or explained by the independent variables.…

  12. Differential Effects of Oral and Written Corrective Feedback in the ESL Classroom

    ERIC Educational Resources Information Center

    Sheen, Younghee

    2010-01-01

    This article examines whether there is any difference between the effect of oral and written corrective feedback (CF) on learners' accurate use of English articles. To this end, the current research presents the results of a quasi-experimental study with a pretest, immediate-posttest, delayed-posttest design, using 12 intact intermediate…

  13. The Effect of Speaker Variables on the Self-Correction Behavior of L2 Learners.

    ERIC Educational Resources Information Center

    Kormos, J.

    1999-01-01

    Explores the effect of individual speaking style on the self-correction behavior of second-language speakers. The project involved 30 Hungarian learners of English studying at various levels of proficiency and made use of self-report data. (Author/VWL)

  14. A Simulation Study on Methods of Correcting for the Effects of Extreme Response Style

    ERIC Educational Resources Information Center

    Wetzel, Eunike; Böhnke, Jan R.; Rose, Norman

    2016-01-01

    The impact of response styles such as extreme response style (ERS) on trait estimation has long been a matter of concern to researchers and practitioners. This simulation study investigated three methods that have been proposed for the correction of trait estimates for ERS effects: (a) mixed Rasch models, (b) multidimensional item response models,…

  15. The Effect of Direct and Indirect Corrective Feedback on Iranian EFL Learners' Spelling Errors

    ERIC Educational Resources Information Center

    Ghandi, Maryam; Maghsoudi, Mojtaba

    2014-01-01

    The aim of the current study was to investigate the impact of indirect corrective feedback on promoting Iranian high school students' spelling accuracy in English (as a foreign language). It compared the effect of direct feedback with indirect feedback on students' written work dictated by their teacher from Chicken Soup for the Mother and…

  16. Polycapillary Optics for Materials Science Studies: Instrumental Effects and Their Correction

    PubMed Central

    Leoni, M.; Welzel, U.; Scardi, P.

    2004-01-01

    The instrumental effects related to the use of a polycapillary x-ray lens as primary beam collimator are here studied and the features observed in the measurements modelled via Monte-Carlo ray-tracing. Comparison with existing procedures is presented and experimental evidence of the accuracy improvements due to the use of a correction algorithm is shown. PMID:27366595

  17. Evidence on the Effectiveness of Comprehensive Error Correction in Second Language Writing

    ERIC Educational Resources Information Center

    Van Beuningen, Catherine G.; De Jong, Nivja H.; Kuiken, Folkert

    2012-01-01

    This study investigated the effect of direct and indirect comprehensive corrective feedback (CF) on second language (L2) learners' written accuracy (N = 268). The study set out to explore the value of CF as a revising tool as well as its capacity to support long-term accuracy development. In addition, we tested Truscott's (e.g., 2001, 2007) claims…

  18. Evaluating the Effectiveness of Combining the Use of Corrective Feedback and High-Level Practice Questions

    ERIC Educational Resources Information Center

    Fenesi, Barbara; Sana, Faria; Kim, Joseph A.

    2014-01-01

    A growing trend in teaching practices is to combine instructional techniques to optimize learning. If two instructional techniques can independently facilitate comprehension, it may be reasonable to assume that their combination would contribute to even greater learning. Here we examine the effects of using corrective feedback (present or absent)…

  19. Effects of road traffic background noise on judgments of individual airplane noises. Ph.D. Thesis

    NASA Technical Reports Server (NTRS)

    Powell, C. A.

    1979-01-01

    Two laboratory experiments were conducted to investigate the effects of road-traffic background noise on judgments of individual airplane flyover noises. In the first experiment, 27 subjects judged a set of 16 airplane flyover noises in the presence of traffic-noise sessions of 30-min duration consisting of the combinations of 3 traffic-noise types and 3 noise levels. In the second experiment, 24 subjects judged the same airplane flyover noises in the presence of traffic-noise sessions of 10-min duration consisting of the combinations of 2 traffic-noise types and 4 noise levels. In both experiments the airplane noises were judged less annoying in the presence of high traffic-noise levels than in the presence of low traffic-noise levels.

  20. Genetic Background, Maternal Age, and Interaction Effects Mediate Rates of Crossing Over in Drosophila melanogaster Females.

    PubMed

    Hunter, Chad M; Robinson, Matthew C; Aylor, David L; Singh, Nadia D

    2016-01-01

    Meiotic recombination is a genetic process that is critical for proper chromosome segregation in many organisms. Despite being fundamental for organismal fitness, rates of crossing over vary greatly between taxa. Both genetic and environmental factors contribute to phenotypic variation in crossover frequency, as do genotype-environment interactions. Here, we test the hypothesis that maternal age influences rates of crossing over in a genotypic-specific manner. Using classical genetic techniques, we estimated rates of crossing over for individual Drosophila melanogaster females from five strains over their lifetime from a single mating event. We find that both age and genetic background significantly contribute to observed variation in recombination frequency, as do genotype-age interactions. We further find differences in the effect of age on recombination frequency in the two genomic regions surveyed. Our results highlight the complexity of recombination rate variation and reveal a new role of genotype by maternal age interactions in mediating recombination rate. PMID:26994290

  1. Genetic Background, Maternal Age, and Interaction Effects Mediate Rates of Crossing Over in Drosophila melanogaster Females

    PubMed Central

    Hunter, Chad M.; Robinson, Matthew C.; Aylor, David L.; Singh, Nadia D.

    2016-01-01

    Meiotic recombination is a genetic process that is critical for proper chromosome segregation in many organisms. Despite being fundamental for organismal fitness, rates of crossing over vary greatly between taxa. Both genetic and environmental factors contribute to phenotypic variation in crossover frequency, as do genotype–environment interactions. Here, we test the hypothesis that maternal age influences rates of crossing over in a genotypic-specific manner. Using classical genetic techniques, we estimated rates of crossing over for individual Drosophila melanogaster females from five strains over their lifetime from a single mating event. We find that both age and genetic background significantly contribute to observed variation in recombination frequency, as do genotype–age interactions. We further find differences in the effect of age on recombination frequency in the two genomic regions surveyed. Our results highlight the complexity of recombination rate variation and reveal a new role of genotype by maternal age interactions in mediating recombination rate. PMID:26994290

  2. The effect of collective flavor oscillations on the diffuse supernova neutrino background

    SciTech Connect

    Chakraborty, Sovan; Kar, Kamales; Dasgupta, Basudeb E-mail: sandhya@hri.res.in E-mail: basudeb@theory.tifr.res.in

    2008-09-15

    Collective flavor oscillations driven by neutrino-neutrino interactions inside core-collapse supernovae have now been shown to drastically alter the resultant neutrino fluxes. This would in turn significantly affect the diffuse supernova neutrino background (DSNB), created by all core-collapse supernovae that have exploded in the past. In view of these collective effects, we re-analyze the potential for detecting the DSNB in currently running and planned large scale detectors meant for detecting both {nu}-bar{sub e} and {nu}{sub e}. We find that the event rate can be different from previous estimates by up to 50%, depending on the value of {theta}{sub 13}. The next generation detectors should be able to observe DSNB fluxes. Under certain conducive conditions, one could learn about neutrino parameters. For instance, it might be possible to determine the neutrino mass hierarchy, even if {theta}{sub 13}{yields}0.

  3. Background Knowledge and Its Effect on Standardized Reading Comprehension Test Performance

    ERIC Educational Resources Information Center

    Awabdy, Graziella Whipple

    2012-01-01

    An investigation of the relationship between background knowledge and reading comprehension performance on standardized reading tests (the California STAR Test) was conducted with sixth, seventh, and eighth-grade ethnic minority children from low-income backgrounds (N = 68). Predictor variables examined included perceived background knowledge…

  4. Alzheimer's disease detection using 11C-PiB with improved partial volume effect correction

    NASA Astrophysics Data System (ADS)

    Raniga, Parnesh; Bourgeat, Pierrick; Fripp, Jurgen; Acosta, Oscar; Ourselin, Sebastien; Rowe, Christopher; Villemagne, Victor L.; Salvado, Olivier

    2009-02-01

    Despite the increasing use of 11C-PiB in research into Alzheimer's disease (AD), there are few standardized analysis procedures that have been reported or published. This is especially true with regards to partial volume effects (PVE) and partial volume correction. Due to the nature of PET physics and acquisition, PET images exhibit relatively low spatial resolution compared to other modalities, resulting in bias of quantitative results. Although previous studies have applied PVE correction techniques on 11C-PiB data, the results have not been quantitatively evaluated and compared against uncorrected data. The aim of this study is threefold. Firstly, a realistic synthetic phantom was created to quantify PVE. Secondly, MRI partial volume estimate segmentations were used to improve voxel-based PVE correction instead of using hard segmentations. Thirdly, quantification of PVE correction was evaluated on 34 subjects (AD=10, Normal Controls (NC)=24), including 12 PiB positive NC. Regional analysis was performed using the Anatomical Automatic Labeling (AAL) template, which was registered to each patient. Regions of interest were restricted to the gray matter (GM) defined by the MR segmentation. Average normalized intensity of the neocortex and selected regions were used to evaluate the discrimination power between AD and NC both with and without PVE correction. Receiver Operating Characteristic (ROC) curves were computed for the binary discrimination task. The phantom study revealed signal losses due to PVE between 10 to 40 % which were mostly recovered to within 5% after correction. Better classification was achieved after PVE correction, resulting in higher areas under ROC curves.

  5. Effects and correction of magneto-optic spatial light modulator phase errors in an optical correlator

    NASA Technical Reports Server (NTRS)

    Downie, John D.; Hine, Butler P.; Reid, Max B.

    1992-01-01

    The optical phase errors introduced into an optical correlator by the input and filter plane magnetooptic spatial light modulators have been studied. The magnitude of these phase errors is measured and characterized, their effects on the correlation results are evaluated, and a means of correction by a design modification of the binary phase-only optical-filter function is presented. The efficacy of the phase-correction technique is quantified and is found to restore the correlation characteristics to those obtained in the absence of errors, to a high degree. The phase errors of other correlator system elements are also discussed and treated in a similar fashion.

  6. Methods for correcting microwave scattering and emission measurements for atmospheric effects

    NASA Technical Reports Server (NTRS)

    Komen, M. (Principal Investigator)

    1975-01-01

    The author has identified the following significant results. Algorithms were developed to permit correction of scattering coefficient and brightness temperature for the Skylab S193 Radscat for the effects of cloud attenuation. These algorithms depend upon a measurement of the vertically polarized excess brightness temperature at 50 deg incidence angle. This excess temperature is converted to an equivalent 50 deg attenuation, which may then be used to estimate the horizontally polarized excess brightness temperature and reduced scattering coefficient at 50 deg. For angles other than 50 deg, the correction also requires use of the variation of emissivity with salinity and water temperature.

  7. Lorentz effect imaging of ionic currents in solution using correct values for ion mobility

    NASA Astrophysics Data System (ADS)

    Wijesinghe, Ranjith S.; Roth, Bradley J.

    2010-06-01

    Truong and his colleagues have recently published a paper introducing a new method called Lorentz effect imaging (LEI) to detect ionic currents in a solution. Their main goal was to prove that the Lorentz force acting on ions in the presence of a static magnetic field could be used as a contrast mechanism to measure neural currents with magnetic resonance imaging. However, they failed to use the correct values for the ion mobilities. In this investigation, we have used correct ion mobility values and show that LEI cannot be used as a contrast mechanism to directly image neural currents.

  8. Retrieval of atmospheric methane from high spectral resolution satellite measurements: a correction for cirrus cloud effects.

    PubMed

    Bril, Andrey; Oshchepkov, Sergey; Yokota, Tatsuya

    2009-04-10

    We assessed the accuracy of methane (CH(4)) retrievals from synthetic radiance spectra particular to Greenhouse Gases Observing Satellite observations. We focused on estimating the CH(4) vertical column amount from an atmosphere that includes thin cirrus clouds, taking into account uncertain meteorological conditions. A photon path-length probability density function (PPDF)-based method was adapted to correct for atmospheric scattering effects in CH(4) retrievals. This method was shown to provide similar retrieval accuracy as compared to a carbon dioxide (CO(2))-proxy-based correction approach. It infers some advantages of PPDF-based method for methane retrievals under high variability of CO(2) abundance. PMID:19363553

  9. Foreground Cleaning for Cosmic Microwave Background Polarimeters in the Presence of Instrumental Effects

    NASA Astrophysics Data System (ADS)

    Bao, Chaoyun

    The Cosmic Microwave Background (CMB) B-mode polarization signal offers a direct probe of inflation, a period of exponential expansion in the extreme early universe. The inflationary CMB B-mode polarization signal, however, is subject to the contamination of polarized galactic thermal dust foreground emission. A robust foreground cleaning method is essential for CMB polarimeters targeting the inflationary B-mode signal. In this thesis I present my work on developing foreground cleaning algorithms particularly in the presence of instrumental effects. One of the instrumental effects I focus on in this work is the frequency dependent polarization rotation effect such as the one caused by an achromatic half-wave plate (AHWP). As an example, I use the AHWP of the E and B Experiment (EBEX) in this work and study the relation between the frequency dependent rotation effect and the characteristic parameters of the AHWP. To address the effect of an AHWP while removing galactic dust foreground contamination, I developed two foreground cleaning algorithms: a simple method that assumes perfect knowledge of the AHWP and a few simplifying assumptions, and a more sophisticated algorithm based on maximum likelihood method. Based on simulation results, the maximum likelihood foreground cleaning algorithm can recover CMB B-mode signal without any bias in the presence of band shape uncertainty, frequency dependent rotation effect and instrumental noise with realistic measurement accuracy of instrumental parameters. In this thesis I also present my work on calculating the atmospheric loading in the millimeter wave regime for sub-orbital CMB experiments such as EBEX. Having a proper prediction of the atmospheric loading is an important input to detector designs for CMB experiments.

  10. Brain Responses before and after Intensive Second Language Learning: Proficiency Based Changes and First Language Background Effects in Adult Learners

    PubMed Central

    White, Erin Jacquelyn; Genesee, Fred; Steinhauer, Karsten

    2012-01-01

    This longitudinal study tracked the neuro-cognitive changes associated with second language (L2) grammar learning in adults in order to investigate how L2 processing is shaped by a learner’s first language (L1) background and L2 proficiency. Previous studies using event-related potentials (ERPs) have argued that late L2 learners cannot elicit a P600 in response to L2 grammatical structures that do not exist in the L1 or that are different in the L1 and L2. We tested whether the neuro-cognitive processes underlying this component become available after intensive L2 instruction. Korean- and Chinese late-L2-learners of English were tested at the beginning and end of a 9-week intensive English-L2 course. ERPs were recorded while participants read English sentences containing violations of regular past tense (a grammatical structure that operates differently in Korean and does not exist in Chinese). Whereas no P600 effects were present at the start of instruction, by the end of instruction, significant P600s were observed for both L1 groups. Latency differences in the P600 exhibited by Chinese and Korean speakers may be attributed to differences in L1–L2 reading strategies. Across all participants, larger P600 effects at session 2 were associated with: 1) higher levels of behavioural performance on an online grammaticality judgment task; and 2) with correct, rather than incorrect, behavioural responses. These findings suggest that the neuro-cognitive processes underlying the P600 (e.g., “grammaticalization”) are modulated by individual levels of L2 behavioural performance and learning. PMID:23300641

  11. Brain responses before and after intensive second language learning: proficiency based changes and first language background effects in adult learners.

    PubMed

    White, Erin Jacquelyn; Genesee, Fred; Steinhauer, Karsten

    2012-01-01

    This longitudinal study tracked the neuro-cognitive changes associated with second language (L2) grammar learning in adults in order to investigate how L2 processing is shaped by a learner's first language (L1) background and L2 proficiency. Previous studies using event-related potentials (ERPs) have argued that late L2 learners cannot elicit a P600 in response to L2 grammatical structures that do not exist in the L1 or that are different in the L1 and L2. We tested whether the neuro-cognitive processes underlying this component become available after intensive L2 instruction. Korean- and Chinese late-L2-learners of English were tested at the beginning and end of a 9-week intensive English-L2 course. ERPs were recorded while participants read English sentences containing violations of regular past tense (a grammatical structure that operates differently in Korean and does not exist in Chinese). Whereas no P600 effects were present at the start of instruction, by the end of instruction, significant P600s were observed for both L1 groups. Latency differences in the P600 exhibited by Chinese and Korean speakers may be attributed to differences in L1-L2 reading strategies. Across all participants, larger P600 effects at session 2 were associated with: 1) higher levels of behavioural performance on an online grammaticality judgment task; and 2) with correct, rather than incorrect, behavioural responses. These findings suggest that the neuro-cognitive processes underlying the P600 (e.g., "grammaticalization") are modulated by individual levels of L2 behavioural performance and learning. PMID:23300641

  12. Effective field theory of gravity: Leading quantum gravitational corrections to Newton's and Coulomb's laws

    SciTech Connect

    Faller, Sven

    2008-06-15

    In this paper we consider general relativity and its combination with scalar quantum electrodynamics (QED) as an effective quantum field theory at energies well below the Planck scale. This enables us to compute the one-loop quantum corrections to the Newton and Coulomb potentials induced by the combination of graviton and photon fluctuations. We derive the relevant Feynman rules and compute the nonanalytical contributions to the one-loop scattering matrix for charged scalars in the nonrelativistic limit. In particular, we derive the post-Newtonian corrections of order Gm/c{sup 2}r from general relativity and the genuine quantum corrections of order G({Dirac_h}/2{pi})/c{sup 3}r{sup 2}.

  13. English vowel identification in quiet and noise: effects of listeners' native language background

    PubMed Central

    Jin, Su-Hyun; Liu, Chang

    2014-01-01

    Purpose: To investigate the effect of listener's native language (L1) and the types of noise on English vowel identification in noise. Method: Identification of 12 English vowels was measured in quiet and in long-term speech-shaped noise and multi-talker babble (MTB) noise for English- (EN), Chinese- (CN) and Korean-native (KN) listeners at various signal-to-noise ratios (SNRs). Results: Compared to non-native listeners, EN listeners performed significantly better in quiet and in noise. Vowel identification in long-term speech-shaped noise and in MTB noise was similar between CN and KN listeners. This is different from our previous study in which KN listeners performed better than CN listeners in English sentence recognition in MTB noise. Discussion: Results from the current study suggest that depending on speech materials, the effect of non-native listeners' L1 on speech perception in noise may be different. That is, in the perception of speech materials with little linguistic cues like isolated vowels, the characteristics of non-native listener's native language may not play a significant role. On the other hand, in the perception of running speech in which listeners need to use more linguistic cues (e.g., acoustic-phonetic, semantic, and prosodic cues), the non-native listener's native language background might result in a different masking effect. PMID:25400538

  14. Detection of trans-Planckian effects in the cosmic microwave background

    SciTech Connect

    Groeneboom, Nicolaas E.; Elgaroey, Oystein

    2008-02-15

    Quantum gravity effects are expected to modify the primordial density fluctuations produced during inflation and leave their imprint on the cosmic microwave background observed today. We present a new analysis discussing whether these effects are detectable, considering both currently available data and simulated results from an optimal CMB experiment. We find that the WMAP (Wilkinson Microwave Anisotropy Probe) data show no evidence for the particular signature considered in this work but give an upper bound on the parameters of the model. However, a hypothetical experiment shows that with proper data, the trans-Planckian effects should be detectable through alternate sampling methods. This fuzzy conclusion is a result of the nature of the oscillations, since they give rise to a likelihood hypersurface riddled with local maxima. A simple Bayesian analysis shows no significant evidence for the simulated data to prefer a trans-Planckian model. Conventional Markov chain Monte Carlo (MCMC) methods are not suitable for exploring this complicated landscape, but alternative methods are required to solve the problem. This, however, requires extremely high-precision data.

  15. Maximum Likelihood Foreground Cleaning for Cosmic Microwave Background Polarimeters in the Presence of Systematic Effects

    NASA Astrophysics Data System (ADS)

    Bao, C.; Baccigalupi, C.; Gold, B.; Hanany, S.; Jaffe, A.; Stompor, R.

    2016-03-01

    We extend a general maximum likelihood foreground estimation for cosmic microwave background (CMB) polarization data to include estimation of instrumental systematic effects. We focus on two particular effects: frequency band measurement uncertainty and instrumentally induced frequency dependent polarization rotation. We assess the bias induced on the estimation of the B-mode polarization signal by these two systematic effects in the presence of instrumental noise and uncertainties in the polarization and spectral index of Galactic dust. Degeneracies between uncertainties in the band and polarization angle calibration measurements and in the dust spectral index and polarization increase the uncertainty in the extracted CMB B-mode power, and may give rise to a biased estimate. We provide a quantitative assessment of the potential bias and increased uncertainty in an example experimental configuration. For example, we find that with 10% polarized dust, a tensor to scalar ratio of r = 0.05, and the instrumental configuration of the E and B experiment balloon payload, the estimated CMB B-mode power spectrum is recovered without bias when the frequency band measurement has 5% uncertainty or less, and the polarization angle calibration has an uncertainty of up to 4°.

  16. Effectiveness analysis of ACOS-Xco2 bias correction method with GEOS-Chem model results

    NASA Astrophysics Data System (ADS)

    Liu, Da; Lei, Liping; Liu, Min; Guo, Lijie; Wang, Qian; Bie, Nian

    2015-08-01

    Satellite observations and model simulations are of two important data sources to study atmospheric carbon dioxide concentration. For analyzing and evaluating the bias correction method of ACOS dry-air column averaged CO2 (Xco2) product, the GEOS-Chem Xco2 simulations are selected according to observing time and locations of the ACOS product. The GEOS-Chem simulations of CO2 profiles are transformed to Xco2 data by convolving with satellite averaging kernels and pressure weighting functions. The GEOS-Chem Xco2 data are then compared with both bias uncorrected and bias corrected satellite retrievals of ACOS. The comparisons show that the bias uncorrected ACOS retrievals are on average 1.12ppm higher than the model Xco2 data, while the corrected ACOS retrievals are only on average 0.06ppm lower than the model Xco2 data. By assuming consistency between model Xco2 simulations and true atmospheric Xco2, this study indicates that the bias can be obvious decreased through the bias correction method, and the correction is effective and necessary for satellite Xco2 retrievals.

  17. Atmospheric correction of ocean-color sensors: effects of the Earth's curvature.

    PubMed

    Ding, K; Gordon, H R

    1994-10-20

    We investigate the influence of the curvature of the Earth on a proposed atmospheric-correction scheme for the Sea-Viewing Wide-Field-of-View Sensor (SeaWiFS) by simulating the radiance exiting the top of a spherical-shell atmosphere and inserting the result into the proposed correction algorithm. The error in the derived water-leaving reflectance suggests that the effects of the curvature are negligible for solar zenith angles (θ(0)) ≤ 70°. Furthermore, for θ(0) > 70° the error in atmospheric correction can usually be reduced if the molecular-scattering component of the top of the atmosphere reflectance (ρ(r)) is computed with a spherical-shell atmosphere radiative transfer code. Also, for θ(0) > 70° the error in atmospheric correction in a spherical-shell atmosphere, when ρ(r) is computed with a spherical-shell model, can be predicted reasonably well from computations made with plane-parallel atmosphere radiative transfer codes. This implies that studies aimed at improving atmospheric correction can be made assuming plane-parallel geometry and that the investigator can be confident when θ(0)> 70° that any improvements will still be valid for a spherical-shell atmosphere as long as ρ(r) is computed in spherical-shell geometry. Finally, a scheme for computing ρ(r) in a spherical-shell atmosphere in a relatively simple manner is developed. PMID:20941262

  18. Effect of van der Waals corrections on DFT-computed metallic surface properties

    NASA Astrophysics Data System (ADS)

    Chiter, Fatah; Bac Nguyen, Van; Tarrat, Nathalie; Benoit, Magali; Tang, Hao; Lacaze-Dufaure, Corinne

    2016-04-01

    State-of-the-art van der Waals (vdW) corrected density functional theory (DFT) is routinely used to overcome the failure of standard DFT in the description of molecule/surface long range interactions. However, the systematic use of dispersion forces to model metallic surfaces could lead to less accurate results than the standard DFT and the effect of these corrections on the metal properties should be properly evaluated. In this framework, the behavior of two widely used vdW corrected DFT methods (DFT-D2 and vdW–DF/optB86b) has been evaluated on six metals, i.e. Al, Cu, Au, Ni, Co and Fe, with respect to standard GGA–DFT and experiments. Regarding bulk properties, general trends are found for the lattice parameter, cohesive energy and magnetic moment variations when the vdW correction is introduced. Surface energies, work functions and interlayer distances of closed packed surfaces, Al(111), Cu(111), Au(111) and magnetic Ni(111), Co(0001) and Fe(110), are also strongly affected by the dispersion forces. These modifications suggest a systematic verification of the surface properties when a dispersion correction is included.

  19. Atmospheric correction of HJ1-A/B images and the effects on remote sensing monitoring of cyanobacteria bloom

    NASA Astrophysics Data System (ADS)

    Ma, H.; Guo, S.; Hong, X.; Zhou, Y.

    2015-05-01

    The HJ-1A/B satellite offers free images with high spatial and temporal resolution, which are effective for dynamically monitoring cyanobacteria blooms. However, the HJ-1A/B satellite also receives distorted signals due to the influence of atmosphere. To acquire accurate information about cyanobacteria blooms, atmospheric correction is needed. HJ-1A/B images were atmosphere corrected using the FLAASH atmospheric correction model. Considering the quantum effect within a certain wavelength range, a spectral response function was included in the process. Then the model was used to process HJ-1A/B images, and the NDVI after atmospheric correction was compared with that before correction. The standard deviation improved from 0.13 to 0.158. Results indicate that atmospheric correction effectively reduces the distorted signals. Finally, NDVI was utilized to monitor the cyanobacteria bloom in Donghu Lake. The accuracy was enhanced compared with that before correction.

  20. The accuracy of climate models' simulated season lengths and the effectiveness of grid scale correction factors

    SciTech Connect

    Winterhalter, Wade E.

    2011-09-01

    Global climate change is expected to impact biological populations through a variety of mechanisms including increases in the length of their growing season. Climate models are useful tools for predicting how season length might change in the future. However, the accuracy of these models tends to be rather low at regional geographic scales. Here, I determined the ability of several atmosphere and ocean general circulating models (AOGCMs) to accurately simulate historical season lengths for a temperate ectotherm across the continental United States. I also evaluated the effectiveness of regional-scale correction factors to improve the accuracy of these models. I found that both the accuracy of simulated season lengths and the effectiveness of the correction factors to improve the model's accuracy varied geographically and across models. These results suggest that regional specific correction factors do not always adequately remove potential discrepancies between simulated and historically observed environmental parameters. As such, an explicit evaluation of the correction factors' effectiveness should be included in future studies of global climate change's impact on biological populations.

  1. The accuracy of climate models' simulated season lengths and the effectiveness of grid scale correction factors

    DOE PAGESBeta

    Winterhalter, Wade E.

    2011-09-01

    Global climate change is expected to impact biological populations through a variety of mechanisms including increases in the length of their growing season. Climate models are useful tools for predicting how season length might change in the future. However, the accuracy of these models tends to be rather low at regional geographic scales. Here, I determined the ability of several atmosphere and ocean general circulating models (AOGCMs) to accurately simulate historical season lengths for a temperate ectotherm across the continental United States. I also evaluated the effectiveness of regional-scale correction factors to improve the accuracy of these models. I foundmore » that both the accuracy of simulated season lengths and the effectiveness of the correction factors to improve the model's accuracy varied geographically and across models. These results suggest that regional specific correction factors do not always adequately remove potential discrepancies between simulated and historically observed environmental parameters. As such, an explicit evaluation of the correction factors' effectiveness should be included in future studies of global climate change's impact on biological populations.« less

  2. Comparison of different approaches for the correction of residual mask proximity effects

    NASA Astrophysics Data System (ADS)

    Mittermeier, E.; Franke, T.

    2005-11-01

    Linearity- and proximity effects do exist on actual masks even if manufactured with current state-of-the-art processes. The impact of these short-range mask effects on the results of the optical lithography for features sizes relevant in the 90nm-node is investigated. For this purpose, an approach is chosen which employs mask process simulations in combination with simulations of optical lithography. Two mask models are deduced and verified from measurement data of an existing mask process. The lithographic results are simulated using parameters of current optical- and process models. Both mask models are used to evaluate the impact of the mask proximity effects on the printing results of optical lithography for critical pattern geometries. The differences in the mask proximity characteristics lead to additional pattern-dependent CD-offtargets after wafer lithography. Additionally, a mask-process dependent sensitivity of the CD-offtarget on the presence of optical sub-resolution assist features is observed. Based on these simulation results, the efficiencies of two techniques for the correction of the mask proximity signatures are evaluated. The application of mask sub-resolution features is compared with model-based data correction on mask level. Mask sub-resolution assist features reduce the influence of the mask process significantly and provide an enhanced stability against mask process fluctuations. Data correction yields even better correction results at the cost of an increased complexity due to the susceptibility to changes of the mask processes characteristics.

  3. Open EFTs, IR effects & late-time resummations: systematic corrections in stochastic inflation

    NASA Astrophysics Data System (ADS)

    Burgess, C. P.; Holman, R.; Tasinato, G.

    2016-01-01

    Though simple inflationary models describe the CMB well, their corrections are often plagued by infrared effects that obstruct a reliable calculation of late-time behaviour. We adapt to cosmology tools designed to address similar issues in other physical systems with the goal of making reliable late-time inflationary predictions. The main such tool is Open EFTs which reduce in the inflationary case to Stochastic Inflation plus calculable corrections. We apply this to a simple inflationary model that is complicated enough to have dangerous IR behaviour yet simple enough to allow the inference of late-time behaviour. We find corrections to standard Stochastic Inflationary predictions for the noise and drift, and we find these corrections ensure the IR finiteness of both these quantities. The late-time probability distribution, {P}(φ ) , for super-Hubble field fluctuations are obtained as functions of the noise and drift and so these too are IR finite. We compare our results to other methods (such as large- N models) and find they agree when these models are reliable. In all cases we can explore in detail we find IR secular effects describe the slow accumulation of small perturbations to give a big effect: a significant distortion of the late-time probability distribution for the field. But the energy density associated with this is only of order H 4 at late times and so does not generate a dramatic gravitational back-reaction.

  4. Correction of resist heating effect on variable shaped beam mask writer

    NASA Astrophysics Data System (ADS)

    Nakayamada, Noriaki; Suganuma, Mizuna; Nomura, Haruyuki; Kato, Yasuo; Kamikubo, Takashi; Ogasawara, Munehiro; Zable, Harold; Masuda, Yukihiro; Fujimura, Aki

    2016-04-01

    The specifications for critical dimension (CD) accuracy and line edge roughness are getting tighter to promote every photomask manufacturer to choose electron beam resists of lower sensitivity. When the resist is exposed by too many electrons, it is excessively heated up to have higher sensitivity at a higher temperature, which results in degraded CD uniformity. This effect is called "resist heating effect" and is now the most critical error source in CD control on a variable shaped beam (VSB) mask writer. We have developed an on-tool, real-time correction system for the resist heating effect. The system is composed of correction software based on a simple thermal diffusion model and computational hardware equipped with more than 100 graphical processing unit chips. We have demonstrated that the designed correction accuracy was obtained and the runtime of correction was sufficiently shorter than the writing time. The system is ready to be deployed for our VSB mask writers to retain the writing time as short as possible for lower sensitivity resists by removing the need for increased pass count.

  5. Phase correction of electromagnetic coupling effects in cross-borehole EIT measurements

    NASA Astrophysics Data System (ADS)

    Zhao, Y.; Zimmermann, E.; Huisman, J. A.; Treichel, A.; Wolters, B.; van Waasen, S.; Kemna, A.

    2015-01-01

    Borehole EIT measurements in a broad frequency range (mHz to kHz) are used to study subsurface geophysical properties. However, accurate measurements have long been difficult because the required long electric cables introduce undesired inductive and capacitive coupling effects. Recently, it has been shown that such effects can successfully be corrected in the case of single-borehole measurements. The aim of this paper is to extend the previously developed correction procedure for inductive coupling during EIT measurements in a single borehole to cross-borehole EIT measurements with multiple borehole electrode chains. In order to accelerate and simplify the previously developed correction procedure for inductive coupling, a pole-pole matrix of mutual inductances is defined. This consists of the inductances of each individual chain obtained from calibration measurements and the inductances between two chains calculated from the known cable positions using numerical modelling. The new correction procedure is successfully verified with measurements in a water-filled pool under controlled conditions where the errors introduced by capacitive coupling were well-defined and could be estimated by FEM forward modelling. In addition, EIT field measurements demonstrate that the correction methods increase the phase accuracy considerably. Overall, the phase accuracy of cross-hole EIT measurements after correction of inductive and capacitive coupling is improved to better than 1 mrad up to a frequency of 1 kHz, which substantially improves our ability to characterize the frequency-dependent complex electrical resistivity of weakly polarizable soils and sediments in situ.

  6. The Effect of Age Correction on Multivariate Classification in Alzheimer's Disease, with a Focus on the Characteristics of Incorrectly and Correctly Classified Subjects.

    PubMed

    Falahati, Farshad; Ferreira, Daniel; Soininen, Hilkka; Mecocci, Patrizia; Vellas, Bruno; Tsolaki, Magda; Kłoszewska, Iwona; Lovestone, Simon; Eriksdotter, Maria; Wahlund, Lars-Olof; Simmons, Andrew; Westman, Eric

    2016-03-01

    The similarity of atrophy patterns in Alzheimer's disease (AD) and in normal aging suggests age as a confounding factor in multivariate models that use structural magnetic resonance imaging (MRI) data. To study the effect and compare different age correction approaches on AD diagnosis and prediction of mild cognitive impairment (MCI) progression as well as investigate the characteristics of correctly and incorrectly classified subjects. Data from two multi-center cohorts were included in the study [AD = 297, MCI = 445, controls (CTL) = 340]. 34 cortical thickness and 21 subcortical volumetric measures were extracted from MRI. The age correction approaches involved: using age as a covariate to MRI-derived measures and linear detrending of age-related changes based on CTL measures. Orthogonal projections to latent structures was used to discriminate between AD and CTL subjects, and to predict MCI progression to AD, up to 36-months follow-up. Both age correction approaches improved models' quality in terms of goodness of fit and goodness of prediction, as well as classification and prediction accuracies. The observed age associations in classification and prediction results were effectively eliminated after age correction. A detailed analysis of correctly and incorrectly classified subjects highlighted age associations in other factors: ApoE genotype, global cognitive impairment and gender. The two methods for age correction gave similar results and show that age can partially masks the influence of other aspects such as cognitive impairment, ApoE-e4 genotype and gender. Age-related brain atrophy may have a more important association with these factors than previously believed. PMID:26440606

  7. Correction of Doppler-broadened Rayleigh backscattering effects in H2O dial measurements

    NASA Technical Reports Server (NTRS)

    Ansmann, A.; Bosenberg, J.

    1986-01-01

    A general method of solutions for treating effects of Doppler-broadened Rayleigh backscattering in H2O Differential Absorption Lidar (DIAL) measurements are described and discussed. Errors in vertical DIAL measuremtns caused by this laser line broadening effect can be very large and, therfore, this effect has to be accounted for accurately. To analyze and correct effects of Doppler-broadened Rayleigh backscattering in DIAL experiments, a generalized DIAL approximation was derived starting from a lidar equation, which includes Doppler broadening. To evaluate the accuracy of H2O DIAL measurements, computer simulations were performed. It was concluded that correction of Doppler broadened Rayleigh backscattering is possible with good accuracy in most cases of tropospheric H2O DIAL measurements, but great care has to be taken when layers with steep gradients of Mie backscattering like clouds or inversion layers are present.

  8. Analysis and correction of ground reflection effects in measured narrowband sound spectra using cepstral techniques

    NASA Technical Reports Server (NTRS)

    Miles, J. H.; Stevens, G. H.; Leininger, G. G.

    1975-01-01

    Ground reflections generate undesirable effects on acoustic measurements such as those conducted outdoors for jet noise research, aircraft certification, and motor vehicle regulation. Cepstral techniques developed in speech processing are adapted to identify echo delay time and to correct for ground reflection effects. A sample result is presented using an actual narrowband sound pressure level spectrum. The technique can readily be adapted to existing fast Fourier transform type spectrum measurement instrumentation to provide field measurements/of echo time delays.

  9. Mars: Correcting surface albedo observations for effects of atmospheric dust loading

    NASA Technical Reports Server (NTRS)

    Lee, S. W.; Clancy, R. T.

    1992-01-01

    We have developed a radiative transfer model which allows the effects of atmospheric dust loading on surface albedo to be investigated. This model incorporates atmospheric dust opacity, the single scattering albedo and particle phase function of atmospheric dust, the bidirectional reflectance of the surface, and variable lighting and viewing geometry. The most recent dust particle properties are utilized. The spatial and temporal variability of atmospheric opacity (Tan) strongly influences the radiative transfer modelling results. We are currently using the approach described to determine Tan for IRTM mapping sequences of selected regions. This approach allows Tan to be determined at the highest spatial and temporal resolution supported by the IRTM data. Applying the radiative transfer modelling and determination of Tan described, IRTM visual brightness observations can be corrected for the effects of atmospheric dust loading a variety of locations and times. This approach allows maps of 'dust-corrected surface albedo' to be constructed for selected regions. Information on the variability of surface albedo and the amount of dust deposition/erosion related to such variability results. To date, this study indicates that atmospheric dust loading has a significant effect on observations of surface albedo, amounting to albedo corrections of as much as several tens of percent. This correction is not constant or linear, but depends upon surface albedo, viewing and lighting geometry, the dust and surface phase functions, and the atmospheric opacity. It is clear that the quantitative study of surface albedo, especially where small variations in observed albedo are important (such as photometric analyses), needs to account for the effects of the atmospheric dust loading. Maps of 'dust-corrected surface albedo' will be presented for a number of regions.

  10. Dielectric relaxation time of bulk water at 136-140 K, background loss and crystallization effects

    NASA Astrophysics Data System (ADS)

    Johari, G. P.

    2005-04-01

    Dielectric relaxation time, τ, of ultraviscous bulk water has been determined by analyzing its loss tangent, tanδ, data, which had been measured on heating the vapor-deposited amorphous solid water and hyperquenched glassy water in our earlier studies. [Johari, Hallbrucker, and Mayer, J. Chem. Phys. 95, 2955 (1991); 97, 5851 (1992)]. As for glasses and liquids generally, the measured tanδ of water is the sum of a frequency-independent background loss and a frequency-dependent relaxational loss. A two-frequency method is provided for determining the background loss and used for obtaining the relaxational part of tanδ. After considering the structural relaxation and crystal-nuclei growth effects, τ for water has been determined. At 136±1K, it is 2.5±0.6s when a single relaxation time is (untenably) assumed, and 42±14s when a distribution of relaxation times, a characteristic of viscous liquids, is assumed, with Davidson-Cole distribution parameter of 0.75. Structural relaxation time of ˜70s for water at 136K, which was originally estimated from the DSC endotherm [Johari, Hallbrucker, and Mayer, Nature (London) 330, 552 (1987)], has been revised to ˜33s. Temperature dependence of τ could not be determined because ultraviscous water crystallizes too rapidly to cubic ice containing stacking faults and intergranular water. The study demonstrates that water is a liquid over the 136-155K range, thus removing the basis for a recent contention on its state.

  11. Modeling estimates of the effect of acid rain on background radiation dose.

    PubMed Central

    Sheppard, S C; Sheppard, M I

    1988-01-01

    Acid rain causes accelerated mobilization of many materials in soils. Natural and anthropogenic radionuclides, especially 226Ra and 137Cs, are among these materials. Okamoto is apparently the only researcher to date who has attempted to quantify the effect of acid rain on the "background" radiation dose to man. He estimated an increase in dose by a factor of 1.3 following a decrease in soil pH of 1 unit. We reviewed literature that described the effects of changes in pH on mobility and plant uptake of Ra and Cs. Generally, a decrease in soil pH by 1 unit will increase mobility and plant uptake by factors of 2 to 7. Thus, Okamoto's dose estimate may be too low. We applied several simulation models to confirm Okamoto's ideas, with most emphasis on an atmospherically driven soil model that predicts water and nuclide flow through a soil profile. We modeled a typical, acid-rain sensitive soil using meteorological data from Geraldton, Ontario. The results, within the range of effects on the soil expected from acidification, showed essentially direct proportionality between the mobility of the nuclides and dose. This supports some of the assumptions invoked by Okamoto. We conclude that a decrease in pH of 1 unit may increase the mobility of Ra and Cs by a factor of 2 or more. Our models predict that this will lead to similar increases in plant uptake and radiological dose to man. Although health effects following such a small increase in dose have not been statistically demonstrated, any increase in dose is probably undesirable. PMID:3203639

  12. Modeling estimates of the effect of acid rain on background radiation dose.

    PubMed

    Sheppard, S C; Sheppard, M I

    1988-06-01

    Acid rain causes accelerated mobilization of many materials in soils. Natural and anthropogenic radionuclides, especially 226Ra and 137Cs, are among these materials. Okamoto is apparently the only researcher to date who has attempted to quantify the effect of acid rain on the "background" radiation dose to man. He estimated an increase in dose by a factor of 1.3 following a decrease in soil pH of 1 unit. We reviewed literature that described the effects of changes in pH on mobility and plant uptake of Ra and Cs. Generally, a decrease in soil pH by 1 unit will increase mobility and plant uptake by factors of 2 to 7. Thus, Okamoto's dose estimate may be too low. We applied several simulation models to confirm Okamoto's ideas, with most emphasis on an atmospherically driven soil model that predicts water and nuclide flow through a soil profile. We modeled a typical, acid-rain sensitive soil using meteorological data from Geraldton, Ontario. The results, within the range of effects on the soil expected from acidification, showed essentially direct proportionality between the mobility of the nuclides and dose. This supports some of the assumptions invoked by Okamoto. We conclude that a decrease in pH of 1 unit may increase the mobility of Ra and Cs by a factor of 2 or more. Our models predict that this will lead to similar increases in plant uptake and radiological dose to man. Although health effects following such a small increase in dose have not been statistically demonstrated, any increase in dose is probably undesirable. PMID:3203639

  13. The effects of cosmic microwave background (CMB) temperature uncertainties on cosmological parameter estimation

    SciTech Connect

    Hamann, Jan; Wong, Yvonne Y Y E-mail: ywong@mppmu.mpg.de

    2008-03-15

    We estimate the effect of the experimental uncertainty in the measurement of the temperature of the cosmic microwave background (CMB) on the extraction of cosmological parameters from future CMB surveys. We find that even for an ideal experiment limited only by cosmic variance up to l=2500 for both the temperature and polarization measurements, the projected cosmological parameter errors are remarkably robust against the uncertainty of 1 mK in the firas CMB temperature monopole measurement. The maximum degradation in sensitivity is 20%, for the baryon density estimate, relative to the case in which the monopole is known infinitely well. While this degradation is acceptable, we note that reducing the uncertainty in the current temperature measurement by a factor of five will bring it down to {approx}1%. We also estimate the effect of the uncertainty in the dipole temperature measurement. Assuming the overall calibration of the data to be dominated by the dipole error of 0.2% from firas, the sensitivity degradation is insignificant and does not exceed 10% in any parameter direction.

  14. US Air Force Space Weather Products Rapid Prototyping Efforts - Solar Radio Background/Burst Effects and Meteor Effects Products

    NASA Astrophysics Data System (ADS)

    Quigley, S.; Scro, K.

    2001-12-01

    The Space Vehicles Directorate of the Air Force Research Laboratory (AFRL/VSB) has joined efforts with the Technology Applications Division of the Space and Missile Systems Center (SMC Det 11/CIT) to rapidly transition space weather research into prototype, operational, system-impact products. These Rapid Prototyping Center (RPC) products are used to analyze, specify, and forecast the effects of the near-earth space environment on Department of Defense systems and communications. A summary of RPC activity is provided. Emphasis will be placed on current products under development, to include Solar Radio Background/Burst Effects (SoRBE) and Meteor Effects (ME) products. These will be added to real-time operations in the near future. SoRBE specifies the detrimental interference effects of background and event-level solar radio output on radar observations and satellite communications. ME will provide general meteor shower "nowcast" and forecast information, along with more specific meteor and meteor shower impact, radar clutter, and bolide (exploding meteor) effects. A brief overview of recently delivered products: Radar Auroral Clutter, Satellite Scintillation, HF Illumination, and GPS Single-Frequency Error Maps will also be provided.

  15. An Investigation of the Effects of Background Music on Learning of Vocabulary and Grammar and in Public Speaking.

    ERIC Educational Resources Information Center

    Wolff, Florence I.

    To determine the effect of background music during classroom instruction in vocabulary and grammar and in the delivery of speeches, sophomore high school students were divided into an experimental group (66 students) and a control group (60 students). For one semester the experimental group heard classical background music during instruction,…

  16. Measuring the Socio-Economic Background of Students and Its Effect on Achievement on PISA 2000 and PISA 2003

    ERIC Educational Resources Information Center

    Schulz, Wolfram

    2005-01-01

    One of the consistent findings of educational research studies is the effect of the students' family socio-economic background on their learning achievement. Consequently, international comparative studies emphasis the role of socio-economic background for determining learning outcomes. In particular, PISA results have been used to describe how…

  17. A Hydrodynamic Approach to Cosmology: Nonlinear Effects on Cosmic Backgrounds in the Cold Dark Matter Model

    NASA Astrophysics Data System (ADS)

    Scaramella, Roberto; Cen, Renyue; Ostriker, Jeremiah P.

    1993-10-01

    Using the CDM model as a testbed, we produce and analyze sky maps of fluctuations in the cosmic background radiation field due to Sunyaev-Zel'dovich effect, as well as those seen in X-ray background at 1 keV and at 2 keV. These effects are due to the shock heating of baryons in the nonlinear phases of cosmic collapses. Comparing observations with computations provides a powerful tool to constrain cosmological models. We use a highly developed Eulerian mesh code with 1283 cells and 2 × 106 particles. Most of our information comes from simulations with box size 64 h-1 Mpc, but other calculations were made with L = 16 h-1 and L = 4 h-1 Mpc. A standard CDM input spectrum was used with amplitude defined by the requirement (ΔM/M)rms = 1/1.5 on 8 h-1 Mpc scales (lower than the COBE normalization by a factor of 1.6±0.4), with H0 = 50 km s-1 Mpc-1 and Ωb = 0.05. For statistical validity a large number of independent simulations must be run. In all, over 60 simulations were run from z = 20 to z = 0. We produce maps of 50' x 50' with 1' effective resolution by randomly stacking along the past light cone for 0.02 ≤ z ≤ 10 appropriate combinations of computational boxes of different comoving lengths, which are picked from among different realizations of initial conditions. We also compute time evolution, present intensity pixel distributions, and the autocorrelation function of sky fluctuations as a function of angular scale. Our most reliable results are obtained after deletion of bright sources having 1 keV intensity greater than 0.1 keV cm-2 sr-1 s-1 keV-1. Then for the Sunyaev-Zel'dovich parameter γ the mean and dispersion are [barγ, σ(γ)] = (4, 3) × 10-7 with a lognormal distribution providing a good fit for values of y greater than average. The angular correlation function (less secure) is roughly exponential with scale length ˜2'.5. For the X-ray intensity fluctuations, in units of keV s-1 sr-1 cm-2 keV-1 we find barIX1, X2 = (0.02, 0.006) and σX1, X2 = (0

  18. A new correction of stellar oscillation frequencies for near-surface effects

    NASA Astrophysics Data System (ADS)

    Ball, W. H.; Gizon, L.

    2014-08-01

    Context. Space-based observations of solar-like oscillations present an opportunity to constrain stellar models using individual mode frequencies. However, current stellar models are inaccurate near the surface, which introduces a systematic difference that must be corrected. Aims: We introduce and evaluate two parametrizations of the surface corrections based on formulae given by Gough (1990, LNP, 367, 283). The first we call a cubic term proportional to ν3/ ℐ and the second has an additional inverse term proportional to ν-1/ ℐ, where ν and ℐ are the frequency and inertia of an oscillation mode. Methods: We first show that these formulae accurately correct model frequencies of two different solar models (Model S and a calibrated MESA model) when compared to observed BiSON frequencies. In particular, even the cubic form alone fits significantly better than a power law. We then incorporate the parametrizations into a modelling pipeline that simultaneously fits the surface effects and the underlying stellar model parameters. We apply this pipeline to synthetic observations of a Sun-like stellar model, solar observations degraded to typical asteroseismic uncertainties, and observations of the well-studied CoRoT target HD 52265. For comparison, we also run the pipeline with the scaled power-law correction proposed by Kjeldsen et al. (2008, ApJ, 683, L175). Results: The fits to synthetic and degraded solar data show that the method is unbiased and produces best-fit parameters that are consistent with the input models and known parameters of the Sun. Our results for HD 52265 are consistent with previous modelling efforts and the magnitude of the surface correction is similar to that of the Sun. The fit using a scaled power-law correction is significantly worse but yields consistent parameters, suggesting that HD 52265 is sufficiently Sun-like for the same power-law to be applicable. Conclusions: We find that the cubic term alone is suitable for asteroseismic

  19. College and Class Status: The Effect of Social Class Background on College Impact and Outcomes.

    ERIC Educational Resources Information Center

    Walpole, MaryBeth

    This study used data from the national study of the Cooperative Institutional Research Program (CIRP) to investigate the impact of college on income, educational aspirations, and educational attainment for students from low socioeconomic status (SES) backgrounds compared to those from high-SES backgrounds. The study was based on concepts of…

  20. The Effects of Background Noise on Dichotic Listening to Consonant-Vowel Syllables

    ERIC Educational Resources Information Center

    Sequeira, Sarah Dos Santos; Specht, Karsten; Hamalainen, Heikki; Hugdahl, Kenneth

    2008-01-01

    Lateralization of verbal processing is frequently studied with the dichotic listening technique, yielding a so called right ear advantage (REA) to consonant-vowel (CV) syllables. However, little is known about how background noise affects the REA. To address this issue, we presented CV-syllables either in silence or with traffic background noise…

  1. The Effects of Background Television on the Toy Play Behavior of Very Young Children

    ERIC Educational Resources Information Center

    Schmidt, Marie Evans; Pempek, Tiffany A.; Kirkorian, Heather L.; Lund, Anne Frankenfield; Anderson, Daniel R.

    2008-01-01

    This experiment tests the hypothesis that background, adult television is a disruptive influence on very young children's behavior. Fifty 12-, 24-, and 36-month-olds played with a variety of toys for 1 hr. For half of the hour, a game show played in the background on a monaural TV set. During the other half hour, the TV was off. The children…

  2. QCD corrections to vector boson pair production in gluon fusion including interference effects with off-shell Higgs at the LHC

    NASA Astrophysics Data System (ADS)

    Caola, Fabrizio; Dowling, Matthew; Melnikov, Kirill; Röntsch, Raoul; Tancredi, Lorenzo

    2016-07-01

    We compute next-to-leading order (NLO) QCD corrections to the production of two massive electroweak bosons in gluon fusion. We consider both the prompt production process gg → V V and the production mediated by an exchange of an s-channel Higgs boson, gg → H ∗ → V V . We include final states with both on- and off-shell vector bosons with leptonic decays. The gluonic production of vector bosons is a loop-induced process, including both massless and massive quarks in the loop. For gg → ZZ production, we obtain the NLO QCD corrections to the massive loops through an expansion around the heavy top limit. This approximation is valid below the top production threshold, giving a broad range of invariant masses between the Higgs production and the top production thresholds in which our results are valid. We explore the NLO QCD effects in gg → ZZ focusing, in particular, on the interference between prompt and Higgs-mediated processes. We find that the QCD corrections to the interference are large and similar in size to the corrections to both the signal and the background processes. At the same time, we observe that corrections to the interference change rapidly with the four-lepton invariant mass in the region around the ZZ production threshold. We also study the interference effects in gg → W + W - production where, due to technical limitations, we only consider contributions of massless loops. We find that the QCD corrections to the interference in this case are somewhat larger than those for either the signal or the background.

  3. Effective field theory treatment of the neutrino background in direct dark matter detection experiments

    NASA Astrophysics Data System (ADS)

    Dent, James B.; Dutta, Bhaskar; Newstead, Jayden L.; Strigari, Louis E.

    2016-04-01

    Distinguishing a dark matter interaction from an astrophysical neutrino-induced interaction will be major challenge for future direct dark matter searches. In this paper, we consider this issue within nonrelativistic effective field theory (EFT), which provides a well-motivated theoretical framework for determining nuclear responses to dark matter scattering events. We analyze the nuclear energy recoil spectra from the different dark matter-nucleon EFT operators, and compare them to the nuclear recoil energy spectra that are predicted to be induced by astrophysical neutrino sources. We determine that for 11 of the 14 possible operators, the dark matter-induced recoil spectra can be cleanly distinguished from the corresponding neutrino-induced recoil spectra with moderate-size detector technologies that are now being pursued, e.g., these operators would require 0.5 tonne years to be distinguished from the neutrino background for low mass dark matter. Our results imply that in most models detectors with good energy resolution will be able to distinguish a dark matter signal from a neutrino signal, without the need for much larger detectors that must rely on additional information from timing or direction. In addition we calculate up-to-date exclusion limits in the EFT model space using data from the LUX experiment.

  4. Combined effects of frequency and layer removal on background track characteristics of ECE polycarbonate detectors

    NASA Astrophysics Data System (ADS)

    Sohrabi, Mehdi; Soltani, Zahra; Hakimi, Amir

    2016-02-01

    Polycarbonate track detectors (PCTD) when electrochemically etched (ECE) provide excellent characteristics for registering relatively lower-LET charged particles (e.g. alphas, fast-neutron-induced recoils) for many health physics and ion detection applications.The layer removal method of PCTDs by ethylenediamine (EDA) developed in our laboratory reduces the background track (BGT) density significantly. The frequency of the applied electric field strongly affects the BGT density and diameter and thus affects the minimum detection limit (MDL). In order to study the combined effects of the frequency and layer removal on the BGT density and thus on the MDL, this research was conducted. The BGT density versus the layer thickness removed at frequencies up to 12 kHz decrease rapidly to about 10-20 μm above which they reach a minimum constant level, while the mean BGT diameter verses layer removed at all frequencies are constant with flat responses. On the other hand the BGT density and diameter versus frequency at different layers removed up to ~50 μm increase till 4 kHz above which they reach plateaus. The PCTDs with ~20 μm layer removal at frequencies up 1 to 2 kHz showed the lowest MDL. The results are presented and discussed.

  5. Effects of Wind on Background Particle Concentrations at Truck Freight Terminals

    PubMed Central

    Garcia, Ronald; Hart, Jaime E; Davis, Mary E; Reaser, Paul; Natkin, Jonathan; Laden, Francine; Garshick, Eric; Smith, Thomas J.

    2007-01-01

    Truck freight terminals are predominantly located near highways and industrial facilities. This proximity to pollution sources, coupled with meteorological conditions and wind patterns, may affect occupational exposures to particles at these work locations. In order to understand this process, data from an environmental sampling study of particles at US trucking terminals, along with weather and geographic maps, were analyzed to determine the extent to which the transportation of particles from local pollutant sources elevated observed occupational exposures at these locations. To help identify potential upwind sources, wind direction weighted averages and speed measurements were used to construct wind roses, which were superimposed on overhead photos of the terminal and examined for upwind source activity. Statistical tests were performed on these “source” and “non-source” directions to determine whether there were significant differences in observed particle levels between the two groups. Our results provide evidence that nearby upwind pollution sources significantly elevated background concentrations at only a few of the locations sampled, while the majority provided little to no evidence of a significant upwind source effect. PMID:17162479

  6. The effect of geographic range on extinction risk during background and mass extinction

    PubMed Central

    Payne, Jonathan L.; Finnegan, Seth

    2007-01-01

    Wide geographic range is generally thought to buffer taxa against extinction, but the strength of this effect has not been investigated for the great majority of the fossil record. Although the majority of genus extinctions have occurred between major mass extinctions, little is known about extinction selectivity regimes during these “background” intervals. Consequently, the question of whether selectivity regimes differ between background and mass extinctions is largely unresolved. Using logistic regression, we evaluated the selectivity of genus survivorship with respect to geographic range by using a global database of fossil benthic marine invertebrates spanning the Cambrian through the Neogene periods, an interval of ≈500 My. Our results show that wide geographic range has been significantly and positively associated with survivorship for the great majority of Phanerozoic time. Moreover, the significant association between geographic range and survivorship remains after controlling for differences in species richness and abundance among genera. However, mass extinctions and several second-order extinction events exhibit less geographic range selectivity than predicted by range alone. Widespread environmental disturbance can explain the reduced association between geographic range and extinction risk by simultaneously affecting genera with similar ecological and physiological characteristics on global scales. Although factors other than geographic range have certainly affected extinction risk during many intervals, geographic range is likely the most consistently significant predictor of extinction risk in the marine fossil record. PMID:17563357

  7. High-precision simulations of the weak lensing effect on cosmic microwave background polarization

    NASA Astrophysics Data System (ADS)

    Fabbian, Giulio; Stompor, Radek

    2013-08-01

    We studied the accuracy, robustness, and self-consistency of pixel-domain simulations of the gravitational lensing effect on the primordial cosmic microwave background (CMB) anisotropies due to the large-scale structure of the Universe. In particular, we investigated the dependence of the precision of the results precision on some crucial parameters of these techniques and propose a semi-analytic framework to determine their values so that the required precision is a priori assured and the numerical workload simultaneously optimized. Our focus was on the B-mode signal, but we also discuss other CMB observables, such as the total intensity, T, and E-mode polarization, emphasizing differences and similarities between all these cases. Our semi-analytic considerations are backed up by extensive numerical results. Those are obtained using a code, nicknamed lenS2HAT - for lensing using scalable spherical harmonic transforms (S2HAT) - which we have developed in the course of this work. The code implements a version of the previously described pixel-domain approach and permits performing the simulations at very high resolutions and data volumes, thanks to its efficient parallelization provided by the S2HAT library - a parallel library for calculating of the spherical harmonic transforms. The code is made publicly available.

  8. Acute effects of Dry Immersion on kinematic characteristics of postural corrective responses

    NASA Astrophysics Data System (ADS)

    Sayenko, D. G.; Miller, T. F.; Melnik, K. A.; Netreba, A. I.; Khusnutdinova, D. R.; Kitov, V. V.; Tomilovskaya, E. S.; Reschke, M. F.; Gerasimenko, Y. P.; Kozlovskaya, I. B.

    2016-04-01

    Impairments in balance control are inevitable following exposure to microgravity. However, the role of particular sensory system in postural disorders at different stages of the exposure to microgravity still remains unknown. We used a method called Dry Immersion (DI), as a ground-based model of microgravity, to elucidate the effects of 6-h of load-related afferent inputs on kinematic characteristics of postural corrective responses evoked by pushes to the chest of different intensities during upright standing. The structure of postural corrective responses was altered following exposure to DI, which was manifested by: (1) an increase of the ankle and knee flexion during perturbations of medium intensity, (2) the lack of the compensatory hip extension, as well as diminished knee and ankle flexion with a further increase of the perturbation intensity to submaximal level. We suggest that the lack of weight-bearing increases the reactivity of the balance control system, whereas the ability to scale the responses proportionally to the perturbation intensity decreases. Disrupted neuromuscular coordination of postural corrective responses following DI can be attributed to adaptive neural modifications on the spinal and cortical levels. The present study provides evidence that even a short-term lack of load-related afferent inputs alters kinematic patterns of postural corrective responses, and can result in decreased balance control. Because vestibular input is not primarily affected during the DI exposure, our results indicate that activity and the state of the load-related afferents play critical roles in balance control following real or simulated microgravity.

  9. Experimental verification of the minimum number of diffractive zones for effective chromatic correction in the LWIR

    NASA Astrophysics Data System (ADS)

    Ramsey, J. L.; Walsh, K. F.; Smith, M.; Deegan, J.

    2016-05-01

    With the move to smaller pixel sizes in the longwave IR region there has been a push for shorter focal length lenses that are smaller, cheaper and lighter and that resolve lower spatial frequencies. As a result lenses must have better correction for both chromatic and monochromatic aberrations. This leads to the increased use of aspheres and diffractive optical elements (kinoforms). With recent developments in the molding of chalcogenide materials these aspheres and kinoforms are more cost effective to manufacture. Without kinoforms the axial color can be on the order of 15 μm which degrades the performance of the lens at the Nyquist frequency. The kinoforms are now on smaller elements and are correcting chromatic aberration which is on the order of the design wavelength. This leads to kinoform structures that do not require large phase changes and therefore have 1.5 to just over 2 zones. The question becomes how many zones are required to correct small amounts of chromatic aberration in the system and are they functioning as predicted by the lens design software? We investigate both the design performance and the as-built performance of two designs that incorporate kinoforms for the correction of axial chromatic aberration.

  10. Atomic chemistry in turbulent astrophysical media II: Effect of the redshift zero metagalactic background

    DOE PAGESBeta

    Gray, William J.; Scannapieco, Evan

    2016-02-22

    Here, we carry out direct numerical simulations of turbulent astrophysical media exposed to the redshift zero metagalactic background. The simulations assume solar composition and explicitly track ionizations, recombinations, and ion-by-ion radiative cooling for hydrogen, helium, carbon, nitrogen, oxygen, neon, sodium, magnesium, silicon, sulfur, calcium, and iron. Each run reaches a global steady state that depends not only on the ionization parameter,more » $U,$ and mass-weighted average temperature, $${T}_{{\\rm{MW}}},$$ but also on the one-dimensional turbulent velocity dispersion, $${\\sigma }_{{\\rm{1D}}}$$. We carry out runs that span a grid of models with U ranging from 0 to 10–1 and $${\\sigma }_{{\\rm{1D}}}$$ ranging from 3.5 to 58 km s–1, and we vary the product of the mean density and the driving scale of the turbulence, $${nL},$$ which determines the average temperature of the medium, from $${nL}={10}^{16}$$ to $${nL}={10}^{20}$$ cm–2. The turbulent Mach numbers of our simulations vary from $$M\\approx 0.5$$ for the lowest velocity dispersion cases to $$M\\approx 20$$ for the largest velocity dispersion cases. When $$M\\lesssim 1,$$ turbulent effects are minimal, and the species abundances are reasonably described as those of a uniform photoionized medium at a fixed temperature. On the other hand, when $$M\\gtrsim 1,$$ dynamical simulations such as the ones carried out here are required to accurately predict the species abundances. We gather our results into a set of tables to allow future redshift zero studies of the intergalactic medium to account for turbulent effects.« less

  11. Atomic Chemistry in Turbulent Astrophysical Media. II. Effect of the Redshift Zero Metagalactic Background

    NASA Astrophysics Data System (ADS)

    Gray, William J.; Scannapieco, Evan

    2016-02-01

    We carry out direct numerical simulations of turbulent astrophysical media exposed to the redshift zero metagalactic background. The simulations assume solar composition and explicitly track ionizations, recombinations, and ion-by-ion radiative cooling for hydrogen, helium, carbon, nitrogen, oxygen, neon, sodium, magnesium, silicon, sulfur, calcium, and iron. Each run reaches a global steady state that depends not only on the ionization parameter, U, and mass-weighted average temperature, {T}{{MW}}, but also on the one-dimensional turbulent velocity dispersion, {σ }{{1D}}. We carry out runs that span a grid of models with U ranging from 0 to 10-1 and {σ }{{1D}} ranging from 3.5 to 58 km s-1, and we vary the product of the mean density and the driving scale of the turbulence, {nL}, which determines the average temperature of the medium, from {nL}={10}16 to {nL}={10}20 cm-2. The turbulent Mach numbers of our simulations vary from M≈ 0.5 for the lowest velocity dispersion cases to M≈ 20 for the largest velocity dispersion cases. When M≲ 1, turbulent effects are minimal, and the species abundances are reasonably described as those of a uniform photoionized medium at a fixed temperature. On the other hand, when M≳ 1, dynamical simulations such as the ones carried out here are required to accurately predict the species abundances. We gather our results into a set of tables to allow future redshift zero studies of the intergalactic medium to account for turbulent effects.

  12. Correcting the Results of the Wrong Model: Treatment Effects under Early Detection of Cancer

    PubMed Central

    Lee, Shih-Yuan; Tsodikov, Alex

    2013-01-01

    Early detection of cancer leads to variability of the point of diagnosis advanced by the amount of the so-called lead time, a random variable. Estimated treatment effects by the proportional hazards (PH) model may be biased if this variability is ignored. We study how true and PH-estimated treatment effects differ in screened vs. unscreened populations and offer an approximate correction for the reported PH-based estimate that does not require raw data, targeting a meta-analysis-type application. We rely on a joint cancer incidence and survival model of prostate cancer to furnish key information for the correction. The procedure is applied to a series of prostate cancer data analyses using the PH models reported in the literature. Simulations are used for assessing the quality of the method and sensitivity analyses. PMID:24032001

  13. The Barkas-Effect Correction to Bethe-Bloch Stopping Power

    NASA Astrophysics Data System (ADS)

    Porter, L. E.

    A brief history of the discovery of the Barkas-effect correction to the Bethe-Bloch stopping power formula is presented, followed by a recounting of the initial theoretical calculations prepared as a quantitative explanation. A current version of the modified Bethe-Bloch formula is described in detail. An overview of the current capability to assess the validity of several existing formalisms for calculating the Barkas-effect correction term is provided, in the course of which discussion of numerous sources of uncertainty ensues. Finally, an opinion on the significance of this departure from Bethe-Bloch theory is offered, along with a presentation of a few recent developments and of some areas for focus in future exploration in the field of the stopping power of matter for charged particles.

  14. New Approaches for Correction of Interlayer Absorption Effects in X-ray Fluorescence Imaging of Paintings.

    PubMed

    Wróbel, Paweł M; Frączek, Piotr; Lankosz, Marek

    2016-02-01

    The X-ray fluorescence imaging technique allows not only the imaging itself but also the identification of the hidden paint layers what makes it much more versatile as compared with X-ray radiography. One of the main disadvantages of the former method is the fact that the characteristic X-rays from the deeper paint layers are absorbed in the covering layers. This effect is manifested by some artifacts that impede a proper interpretation of the acquired images. In this work, it is shown that the methodology for correction of the interlayer absorption effects can be extended to the case of polychromatic excitation. Additionally, a new approach for determination of the optimal correction parameters has also been presented. The methodology was verified using either the test painting or the mock-up painting both measured with a table-top micro-XRF setup. PMID:26708500

  15. p-Curve and Effect Size: Correcting for Publication Bias Using Only Significant Results.

    PubMed

    Simonsohn, Uri; Nelson, Leif D; Simmons, Joseph P

    2014-11-01

    Journals tend to publish only statistically significant evidence, creating a scientific record that markedly overstates the size of effects. We provide a new tool that corrects for this bias without requiring access to nonsignificant results. It capitalizes on the fact that the distribution of significant p values, p-curve, is a function of the true underlying effect. Researchers armed only with sample sizes and test results of the published findings can correct for publication bias. We validate the technique with simulations and by reanalyzing data from the Many-Labs Replication project. We demonstrate that p-curve can arrive at conclusions opposite that of existing tools by reanalyzing the meta-analysis of the "choice overload" literature. PMID:26186117

  16. Developing effective serious games: the effect of background sound on visual fidelity perception with varying texture resolution.

    PubMed

    Rojas, David; Kapralos, Bill; Cristancho, Sayra; Collins, Karen; Hogue, Andrew; Conati, Cristina; Dubrowski, Adam

    2012-01-01

    Despite the benefits associated with virtual learning environments and serious games, there are open, fundamental issues regarding simulation fidelity and multi-modal cue interaction and their effect on immersion, transfer of knowledge, and retention. Here we describe the results of a study that examined the effect of ambient (background) sound on the perception of visual fidelity (defined with respect to texture resolution). Results suggest that the perception of visual fidelity is dependent on ambient sound and more specifically, white noise can have detrimental effects on our perception of high quality visuals. The results of this study will guide future studies that will ultimately aid in developing an understanding of the role that fidelity, and multi-modal interactions play with respect to knowledge transfer and retention for users of virtual simulations and serious games. PMID:22357023

  17. Broadband EIT borehole measurements with high phase accuracy using numerical corrections of electromagnetic coupling effects

    NASA Astrophysics Data System (ADS)

    Zhao, Y.; Zimmermann, E.; Huisman, J. A.; Treichel, A.; Wolters, B.; van Waasen, S.; Kemna, A.

    2013-08-01

    Electrical impedance tomography (EIT) is gaining importance in the field of geophysics and there is increasing interest for accurate borehole EIT measurements in a broad frequency range (mHz to kHz) in order to study subsurface properties. To characterize weakly polarizable soils and sediments with EIT, high phase accuracy is required. Typically, long electrode cables are used for borehole measurements. However, this may lead to undesired electromagnetic coupling effects associated with the inductive coupling between the double wire pairs for current injection and potential measurement and the capacitive coupling between the electrically conductive shield of the cable and the electrically conductive environment surrounding the electrode cables. Depending on the electrical properties of the subsurface and the measured transfer impedances, both coupling effects can cause large phase errors that have typically limited the frequency bandwidth of field EIT measurements to the mHz to Hz range. The aim of this paper is to develop numerical corrections for these phase errors. To this end, the inductive coupling effect was modeled using electronic circuit models, and the capacitive coupling effect was modeled by integrating discrete capacitances in the electrical forward model describing the EIT measurement process. The correction methods were successfully verified with measurements under controlled conditions in a water-filled rain barrel, where a high phase accuracy of 0.8 mrad in the frequency range up to 10 kHz was achieved. The corrections were also applied to field EIT measurements made using a 25 m long EIT borehole chain with eight electrodes and an electrode separation of 1 m. The results of a 1D inversion of these measurements showed that the correction methods increased the measurement accuracy considerably. It was concluded that the proposed correction methods enlarge the bandwidth of the field EIT measurement system, and that accurate EIT measurements can now

  18. Matrix effects corrections in DDT assay of {sup 239}Pu with the CTEN instrument

    SciTech Connect

    Hollas, C.L.; Arnone, G.; Brunson, G.; Coop, K.

    1997-11-01

    The accuracy of transuranic (TRU) waste assay using the differential die-away technique depends upon significant corrections to compensate for the effects of the matrix material in which the TRU waste is located. We have used a new instrument, the combined thermal/epithermal neutron (CTEN) instrument for the assay of TRU waste, to develop methods to improve the accuracy of these corrections. Neutrons from a pulsed 14-MeV neutron generator are moderated in the walls of the CTEN cavity and induce fission in the TRU material. The prompt neutrons from these fission events are detected in cadmium-wrapped {sup 3}He neutron detectors. We have developed methods of data acquisition and analysis to extract correlation in the neutron signals resulting from fission during active interrogation. This correlation information, in conjunction with the total number of neutrons detected, is used to determine the fraction of fission neutrons transmitted through the matrix material into the {sup 3}He detectors. This determination allows us to cleanly separate the matrix effects into two processes: matrix modification upon the neutron interrogating flux and matrix modification upon the fraction of fission neutrons transmitted to the neutron detectors. Recent results indicate that for some matrix systems, corrections for position dependent effects within the matrix are possible. 7 refs., 7 figs., 1 tab.

  19. A novel partial volume effects correction technique integrating deconvolution associated with denoising within an iterative PET image reconstruction

    SciTech Connect

    Merlin, Thibaut; Visvikis, Dimitris; Fernandez, Philippe; Lamare, Frederic

    2015-02-15

    Purpose: Partial volume effect (PVE) plays an important role in both qualitative and quantitative PET image accuracy, especially for small structures. A previously proposed voxelwise PVE correction method applied on PET reconstructed images involves the use of Lucy–Richardson deconvolution incorporating wavelet-based denoising to limit the associated propagation of noise. The aim of this study is to incorporate the deconvolution, coupled with the denoising step, directly inside the iterative reconstruction process to further improve PVE correction. Methods: The list-mode ordered subset expectation maximization (OSEM) algorithm has been modified accordingly with the application of the Lucy–Richardson deconvolution algorithm to the current estimation of the image, at each reconstruction iteration. Acquisitions of the NEMA NU2-2001 IQ phantom were performed on a GE DRX PET/CT system to study the impact of incorporating the deconvolution inside the reconstruction [with and without the point spread function (PSF) model] in comparison to its application postreconstruction and to standard iterative reconstruction incorporating the PSF model. The impact of the denoising step was also evaluated. Images were semiquantitatively assessed by studying the trade-off between the intensity recovery and the noise level in the background estimated as relative standard deviation. Qualitative assessments of the developed methods were additionally performed on clinical cases. Results: Incorporating the deconvolution without denoising within the reconstruction achieved superior intensity recovery in comparison to both standard OSEM reconstruction integrating a PSF model and application of the deconvolution algorithm in a postreconstruction process. The addition of the denoising step permitted to limit the SNR degradation while preserving the intensity recovery. Conclusions: This study demonstrates the feasibility of incorporating the Lucy–Richardson deconvolution associated with a

  20. Precipitation effects on aerosol concentration in the background EMEP station of Zarra (Valencia), Spain

    NASA Astrophysics Data System (ADS)

    Calvo, Ana Isabel; San Martín, Isabel; Castro, Amaya; Alonso-Blanco, Elisabeth; Alves, Célia; Duarte, Márcio; Fernández-González, Sergio; Fraile, Roberto

    2014-05-01

    Aerosols and precipitation are closely related, presenting a bidirectional influence and constituting an important source of uncertainties on climate change studies. However, they are usually studied independently and in general are only linked to one another for the development or validation of cloud models. The primary and secondary pollutants may be removed by wet and dry deposition. Wet deposition, including in-cloud and below-cloud scavenging processes, can efficiently remove atmospheric aerosols and it is considered a critical process for determining aerosol concentrations in the atmosphere. In this study, aerosols and precipitation data from a background Spanish EMEP (Cooperative Programme for the Monitoring and Evaluation of Long Range Transmission of Air Pollutants in Europe) station located in Zarra, Valencia (Spain) were analyzed (1° 06' W and 39° 05' N, 885 m asl). The effect of precipitation on aerosol concentration was studied and the correlation between the intensity of precipitation and scavenging effect was investigated. In order to evaluate the effects of precipitation on different aerosol size ranges three different aerosol fractions were studied: PM10, PM10-2.5 and PM2.5. In order to eliminate the influence of the air mass changes, only the days in which the air mass of the precipitation day and the previous day had the same origin were considered. Thus, from a total of 3586 rainy days registered from March 2001 to December 2010, 34 precipitation days satisfied this condition and were analyzed. During the period of study, daily precipitation ranged between 0.2 and 28.8 mm, with a mean value of 4 mm. Regarding the origin of the air masses, those from west were dominant at the three height levels investigated (500, 1500 and 3000 m). In order to obtain additional information, aerosol and precipitation chemical composition were also studied in relation to the days of precipitation and the previous days. Furthermore, in order to identify the type

  1. The Effect of Using Simulation for Training Pharmacy Students on Correct Device Technique

    PubMed Central

    2014-01-01

    Objective. To assess the effect of using simulation in pharmacy student training on correct device technique. Methods. A single-blinded, repeated measures, parallel group design study was conducted in 2011, involving all final-year pharmacy students in year 5 (final year) enrolled in the Clinical Pharmacy and Therapeutics course. Students were assessed on device technique at baseline based on previously published checklists for Diskus (DIS), Turbuhaler (TH), and pressurized Metered Dose Inhaler (pMDI). Students were randomly assigned to 2 groups: Intervention A, which included supervised hands-on education in groups and peer assessment/education; and Intervention B, which included supervised hands-on education in groups, peer assessment/education, and a simulated scenario counseling real asthma patients. The simulation involved groups of 6 students counseling 3 asthma patients on inhaler device technique. The counseling involved verbal information and physical demonstration until the patient performed all steps correctly. Student assessments on device technique were repeated 1 week postintervention. Results. At baseline, none of the students in Intervention A (n=54) or Intervention B (n=55) performed correct technique for any of the 3 devices. One week following the intervention, a significantly higher proportion of students in Intervention B demonstrated correct technique for the Diskus, Turbuhaler, and pMDI (60.0%, 70.9%, and 69.1%, respectively) than did students in Intervention A (27.8%, 40.7%, and 42.6%, respectively, p<0.005). Conclusion. Engaging pharmacy students with real asthma patients in a simulated scenario involving correct device technique education resulted in better device technique demonstration skills among students. PMID:25657364

  2. Experimental study of variations in background radiation and the effect on Nuclear Car Wash sensitivity

    SciTech Connect

    Church, J; Slaughter, D; Norman, E; Asztalos, S; Biltoft, P

    2007-02-07

    Error rates in a cargo screening system such as the Nuclear Car Wash [1-7] depend on the standard deviation of the background radiation count rate. Because the Nuclear Car Wash is an active interrogation technique, the radiation signal for fissile material must be detected above a background count rate consisting of cosmic, ambient, and neutron-activated radiations. It was suggested previously [1,6] that the Corresponding negative repercussions for the sensitivity of the system were shown. Therefore, to assure the most accurate estimation of the variation, experiments have been performed to quantify components of the actual variance in the background count rate, including variations in generator power, irradiation time, and container contents. The background variance is determined by these experiments to be a factor of 2 smaller than values assumed in previous analyses, resulting in substantially improved projections of system performance for the Nuclear Car Wash.

  3. Fluorescence of Dyes in Solutions with High Absorbance. Inner Filter Effect Correction

    PubMed Central

    Fonin, Alexander V.; Sulatskaya, Anna I.; Kuznetsova, Irina M.; Turoverov, Konstantin K.

    2014-01-01

    Fluorescence is a proven tool in all fields of knowledge, including biology and medicine. A significant obstacle in its use is the nonlinearity of the dependence of the fluorescence intensity on fluorophore concentration that is caused by the so-called primary inner filter effect. The existing methods for correcting the fluorescence intensity are hard to implement in practice; thus, it is generally considered best to use dilute solutions. We showed that correction must be performed always. Furthermore, high-concentration solutions (high absorbance) are inherent condition in studying of the photophysical properties of fluorescent dyes and the functionally significant interactions of biological macromolecules. We proposed an easy to use method to correct the experimentally recorded total fluorescence intensity and showed that informative component of fluorescence intensity numerically equals to the product of the absorbance and the fluorescence quantum yield of the object. It is shown that if dye molecules do not interact with each other and there is no reabsorption (as for NATA) and spectrofluorimeter provides the proportionality of the detected fluorescence intensity to the part of the absorbed light (that is possible for spectrofluorimeter with horizontal slits) then the dependence of experimentally detected total fluorescence intensity of the dye on its absorbance coincides with the calculated dependence and the correction factor for eliminating the primary inner filter effect can be calculated on the basis of solution absorbance. It was experimentally shown for NATA fluorescence in the wide range of absorbance (at least up to 60). For ATTO-425, which fluorescence and absorption spectra overlap, the elimination of the primary and secondary filter effects and additional spectral analysis allow to conclude that the most probable reason of the deviation of experimentally detected fluorescence intensity dependence on solution absorbance from the calculated dependence

  4. Surgical Correction of Scoliosis in Children with Spastic Quadriplegia: Benefits, Adverse Effects, and Patient Selection

    PubMed Central

    Legg, Julian; Davies, Evan; Raich, Annie L.; Dettori, Joseph R.; Sherry, Ned

    2014-01-01

    Study Rationale Cerebral palsy (CP) is a group of nonprogressive syndromes of posture and motor impairment associated with lesions of the immature brain. Spastic quadriplegia is the most severe form with a high incidence of scoliosis, back pain, respiratory compromise, pelvic obliquity, and poor sitting balance. Surgical stabilization of the spine is an effective technique for correcting deformity and restoring sitting posture. The decision to operate in this group of patients is challenging. Objectives The aim of this study is to determine the benefits of surgical correction of scoliosis in children with spastic quadriplegia, the adverse effects of this treatment, and what preoperative factors affect patient outcome after surgical correction. Materials and Methods A systematic review was undertaken to identify studies describing benefits and adverse effects of surgery in spastic quadriplegia. Factors affecting patient outcome following surgical correction of scoliosis were assessed. Studies involving adults and nonspastic quadriplegia were excluded. Results A total of 10 case series and 1 prospective and 3 retrospective cohort studies met inclusion criteria. There was significant variation in the overall risk of complications (range, 10.9−70.9%), mortality (range, 2.8−19%), respiratory/pulmonary complications (range, 26.9−57.1%), and infection (range, 2.5−56.8%). Factors associated with a worse outcome were a significant degree of thoracic kyphosis, days in the intensive care unit, and poor nutritional status. Conclusion Caregivers report a high degree of satisfaction with scoliosis surgery for children with spastic quadriplegia. There is limited evidence of preoperative factors that can predict patient outcome after scoliosis. There is a need for well-designed prospective studies of scoliosis surgery in spastic quadriplegia. PMID:24715871

  5. Techniques for the correction of topographical effects in scanning Auger electron microscopy

    NASA Technical Reports Server (NTRS)

    Prutton, M.; Larson, L. A.; Poppa, H.

    1983-01-01

    A number of ratioing methods for correcting Auger images and linescans for topographical contrast are tested using anisotropically etched silicon substrates covered with Au or Ag. Thirteen well-defined angles of incidence are present on each polyhedron produced on the Si by this etching. If N1 electrons are counted at the energy of an Auger peak and N2 are counted in the background above the peak, then N1, N1 - N2, (N1 - N2)/(N1 + N2) are measured and compared as methods of eliminating topographical contrast. The latter method gives the best compensation but can be further improved by using a measurement of the sample absorption current. Various other improvements are discussed.

  6. SYSTEMATIC EFFECTS IN INTERFEROMETRIC OBSERVATIONS OF THE COSMIC MICROWAVE BACKGROUND POLARIZATION

    SciTech Connect

    Karakci, Ata; Korotkov, Andrei; Tucker, Gregory S.; Zhang Le; Timbie, Peter; Sutter, P. M.; Wandelt, Benjamin D.; Bunn, Emory F.

    2013-07-15

    The detection of the primordial B-mode spectrum of the polarized cosmic microwave background (CMB) signal may provide a probe of inflation. However, observation of such a faint signal requires excellent control of systematic errors. Interferometry proves to be a promising approach for overcoming such a challenge. In this paper we present a complete simulation pipeline of interferometric observations of CMB polarization, including systematic errors. We employ two different methods for obtaining the power spectra from mock data produced by simulated observations: the maximum likelihood method and the method of Gibbs sampling. We show that the results from both methods are consistent with each other as well as, within a factor of six, with analytical estimates. Several categories of systematic errors are considered: instrumental errors, consisting of antenna gain and antenna coupling errors; and beam errors, consisting of antenna pointing errors, beam cross-polarization, and beam shape (and size) errors. In order to recover the tensor-to-scalar ratio, r, within a 10% tolerance level, which ensures the experiment is sensitive enough to detect the B-signal at r = 0.01 in the multipole range 28 < l < 384, we find that, for a QUBIC-like experiment, Gaussian-distributed systematic errors must be controlled with precisions of |g{sub rms}| = 0.1 for antenna gain, |{epsilon}{sub rms}| = 5 Multiplication-Sign 10{sup -4} for antenna coupling, {delta}{sub rms} Almost-Equal-To 0. Degree-Sign 7 for pointing, {zeta}{sub rms} Almost-Equal-To 0. Degree-Sign 7 for beam shape, and {mu}{sub rms} = 5 Multiplication-Sign 10{sup -4} for beam cross-polarization. Although the combined systematic effects produce a tolerance level on r twice as large for an experiment with linear polarizers, the resulting bias in r for a circular experiment is 15% which is still on the level of desirable sensitivity.

  7. Effects of the Bering Strait closure on AMOC and global climate under different background climates

    NASA Astrophysics Data System (ADS)

    Hu, Aixue; Meehl, Gerald A.; Han, Weiqing; Otto-Bliestner, Bette; Abe-Ouchi, Ayako; Rosenbloom, Nan

    2015-03-01

    Previous studies have suggested that the status of the Bering Strait may have a significant influence on global climate variability on centennial, millennial, and even longer time scales. Here we use multiple versions of the National Center for Atmospheric Research (NCAR) Community Climate System Model (CCSM, versions 2 and 3) to investigate the influence of the Bering Strait closure/opening on the Atlantic Meridional Overturning Circulation (AMOC) and global mean climate under present-day, 15 thousand-year before present (kyr BP), and 112 kyr BP climate boundary conditions. Our results show that regardless of the version of the model used or the widely different background climates, the Bering Strait's closure produces a robust result of a strengthening of the AMOC, and an increase in the northward meridional heat transport in the Atlantic. As a consequence, the climate becomes warmer in the North Atlantic and the surrounding regions, but cooler in the North Pacific, leading to a seesaw-like climate change between these two basins. For the first time it is noted that the absence of the Bering Strait throughflow causes a slower motion of Arctic sea ice, a reduced upper ocean water exchange between the Arctic and North Atlantic, reduced sea ice export and less fresh water in the North Atlantic. These changes contribute positively to the increased upper ocean density there, thus strengthening the AMOC. Potentially these changes in the North Atlantic could have a significant effect on the ice sheets both upstream and downstream in ice age climate, and further influence global sea level changes.

  8. On the effect of cosmic rays in bolometric cosmic microwave background measurements from the stratosphere

    NASA Astrophysics Data System (ADS)

    Masi, S.; Battistelli, E.; de Bernardis, P.; Lamagna, L.; Nati, F.; Nati, L.; Natoli, P.; Polenta, G.; Schillaci, A.

    2010-09-01

    Context. Precision measurements of the anisotropy of the cosmic microwave background (CMB) are able to detect low-level non-Gaussian features caused by either topological defects or the inflation process. These measurements are becoming feasable with the development of large arrays of ultra-sensitive bolometric detectors and their use in balloon-borne or satellite missions. However, the space environment includes a population of cosmic rays (CRs), which produce spurious spikes in bolometric signals. Aims: We analyze the effect of CRs on the measurement of CMB anisotropy maps and the estimate of cosmological non-Gaussianity and angular power spectra of the CMB. Methods: Using accurate simulations of noise and CR events in bolometric detectors, and de-spiking techniques, we produce simulated measured maps and analyze the Gaussianity and power spectrum of the maps for different levels and rates of CR events. Results: We find that a de-spiking technique based on outlier removal in the detector signals contributing to the same sky pixel is effective in removing CR events larger than the noise. However, low level events hidden in the noise produce a positive shift of the average power signal measured by a bolometer, and increase its variance. If the number of hits per pixel is large enough, the data distribution for each sky pixel is approximately Gaussian, but the skewness and the kurtosis of the temperatures of the pixels indicate the presence of some low-level non-Gaussianity. The standard noise estimation pipeline produces a positive bias in the power spectrum at high multipoles. Conclusions: In the case of a typical balloon-borne survey, the CR-induced non-Gaussianity will be marginally detectable in the membrane bolometer channels, but be negligible in the spider-web bolometer channels. In experiments with detector sensitivity better than 100 μK/√{Hz}, in an environment less favorable than the earth stratosphere, the CR-induced non-Gaussianity is likely to

  9. An effective method for on-line corrections of two-axes laser mount

    NASA Astrophysics Data System (ADS)

    Lala, P.; Pivo, K.

    A numerical technique for correcting the automatic laser tracking of low-altitude satellites for the effects of atmospheric drag on the satellite motion is proposed. The approximation method is based on geocentric rather than topocentric parameters and is simple enough to be implemented on a desk-top computer for on-line correction of both along-track and cross-track deviations by entering the error in the initial time. The results of numerical simulations for B-1300 and GEOS A are presented in a table, and the suitability of the method for on-line computer control of the two-axis azimuthal mount used at Ondrejov Observatory is indicated.

  10. Dissipative heating effects and end corrections for viscous Newtonian flow in high shear capillary tube viscometry

    NASA Technical Reports Server (NTRS)

    Jakobsen, J.; Winer, W. O.

    1974-01-01

    The effect of dissipation heating on the apparent viscosity measured in capillary tube viscometry is described in this paper. Conditions of low Reynolds number and high shear are assumed. End corrections to the tube flow are incorporated. The flow curves show decreasing apparent viscosity when the shear stress increases. The configuration of the flow curves plotted in logarithmic presentation are found to be identical for fluids with Newtonian behavior. Convection is the predominant mechanism in removal of the heat in short capillary tube. The estimated upper bound for the shear stress obtainable in short length capillary tubes appears to be of the order of magnitude of 10 MPa limited primarily by the pressure drop associated with the constant end correction from the flat ended inlet and exit of the tube.

  11. Jeans instability of magnetized quantum plasma: Effect of viscosity, rotation and finite Larmor radius corrections

    SciTech Connect

    Jain, Shweta Sharma, Prerana; Chhajlani, R. K.

    2015-07-31

    The Jeans instability of self-gravitating quantum plasma is examined considering the effects of viscosity, finite Larmor radius (FLR) corrections and rotation. The analysis is done by normal mode analysis theory with the help of relevant linearized perturbation equations of the problem. The general dispersion relation is obtained using the quantum magneto hydrodynamic model. The modified condition of Jeans instability is obtained and the numerical calculations have been performed to show the effects of various parameters on the growth rate of Jeans instability.

  12. Empirical effective temperatures and bolometric corrections for early-type stars

    NASA Technical Reports Server (NTRS)

    Code, A. D.; Bless, R. C.; Davis, J.; Brown, R. H.

    1976-01-01

    An empirical effective temperature for a star can be found by measuring its apparent angular diameter and absolute flux distribution. The angular diameters of 32 bright stars in the spectral range O5f to F8 have recently been measured with the stellar interferometer at Narrabri Observatory, and their absolute flux distributions have been found by combining observations of ultraviolet flux from the Orbiting Astronomical Observatory (OAO-2) with ground-based photometry. In this paper, these data have been combined to derive empirical effective temperatures and bolometric corrections for these 32 stars.

  13. Effect of substrate intake and physiological state on background /sup 13/CO/sub 2/ enrichment

    SciTech Connect

    Wolfe, R.R.; Shaw, J.H.F.; Nadel, E.R.; Wolfe, M.H.

    1984-01-01

    The natural enrichment of /sup 13/C in energy substrates varies, and this variation must be taken into account when stable isotopic tracers are used in metabolic studies. This is conventionally accomplished by measuring background samples taken before the tracer infusion begins and subtracting these values from postinfusion values. Whereas this approach is satisfactory if no perturbation occurs between the collection of the background samples and the collection of postinfusion sample, the data presented in this paper show that any change in the metabolic state can significantly alter the background enrichment of expired CO/sub 2/. This study not only confirmed that the introduction of natural energy sources may alter the background enrichment of CO/sub 2/, but we also found that changes in substrate oxidation induced by different physiological states, such as exercise, can cause significant changes in expired CO/sub 2/ enrichments. Conclusions from studies in which oxidation of substrates were measured by means of a /sup 13/C tracer but potential changes in background enrichments were not accounted for must, therefore, be reassessed.

  14. Effectiveness of Mindfulness-Based Cognitive Therapy (MBCT) in Reducing Aggression of Individuals at the Juvenile Correction and Rehabilitation Center

    PubMed Central

    Milani, Atefeh; Nikmanesh, Zahra; Farnam, Ali

    2013-01-01

    Background: In the present era, delinquency in children and adolescents is undoubtedly a difficult and upsetting issue attracting the attention of many experts such as psychologists, sociologists, and criminologists. These experts often try to answer why a number of children and adolescents engage in various crimes such as aggressive and anti-social crimes. They also try to find out how these crimes can be prevented. Objectives: The present study investigates the effectiveness of mindfulness-based cognitive therapy training (MBCT) in reducing aggression in a juvenile correction and rehabilitation center of Zahedan province during years 1991 to 1992. Materials and Methods: This experimental study included an experimental and a control group with a pretest, posttest, and follow-up approach. The Buss and Perry aggression questionnaire (1992) was used for data collection. The sample group included 22 (10 experimental and 12 control groups) adolescent males in a juvenile correction and rehabilitation center of Zahedan province who were selected through a census method. Using a matching method based on the pre-test scores of the aggression questionnaire, they were then divided into two equivalent categories and were randomly assigned to the two groups. Mindfulness-based cognitive training took the group training in 8 sessions administered on experimental group. The follow-up test was conducted two weeks after the end of the posttest sessions. The results were analyzed using ANCOVA. Results: The results of ANCOVA showed that mindfulness-based cognitive training could significantly reduce aggression during posttest and follow-up test phases in the experimental group, compared to the control group (P < 0.01). Moreover, the results indicated the effectiveness of this method in significantly reducing anger, physical aggression, and hostility during posttest and follow-up test phases (P < 0.05). However, no significant reduction was observed in the verbal aggression subscale

  15. Effect of background motion on line bisection performance in normal subjects.

    PubMed

    Na, Duk L; Son, Youngchul; Kim, Chi Hun; Lee, Byung Hwa; Shon, Young-Min; Lee, Kwang Joo; Lee, Kyung Min; Adair, John C; Watson, Robert T; Heilman, Kenneth M

    2002-12-01

    Previous studies have demonstrated that optokinetic stimulation (OKS) influences line bisection (LB) performance in normal subjects and patients with hemispatial neglect. Since subjects were required to attend to stationary targets on a moving background, prior experimental designs might have induced an illusion of target motion or induced motion (IM) in a direction opposite the background. The current study tested whether the IM affects LB performance in normal subjects and how the speed of targets also influences LB. Thirty-two right-handed normal volunteers (aged 28.0 +/- 5.3 years) were asked to bisect stationary lines with a background of horizontal OKS. These stimuli were generated by computer displayed on a large screen via a beam projector. The OKS was varied according to direction (leftward or rightward) and speed (9.4 degrees/sec or 56.1 degrees/sec), producing 4 different experimental conditions. Mean bisection errors in all conditions were compared with a control condition with no background OKS. For each condition, subjects rated the degree of IM on a 5 point scale. With fast rate OKS, subjects reported minimal IM and LB errors were in the same direction as background motion, a finding that replicates previous studies. Conversely, the slow OKS rate caused subjects to report IM and resulted in deviation of the bisection mark in a direction opposite the background OKS. While this discrepancy between the slow and fast OKS conditions might be related to motion illusion, we did not find a direct correlation between the degree of IM and bisection errors and thus reasons for these results remain unexplained. PMID:12507047

  16. In-orbit background of X-ray microcalorimeters and its effects on observations

    NASA Astrophysics Data System (ADS)

    Lotti, S.; Cea, D.; Macculi, C.; Mineo, T.; Natalucci, L.; Perinati, E.; Piro, L.; Federici, M.; Martino, B.

    2014-09-01

    Context. Observations in the X-ray energy band are often limited by the background because of the low fluxes of typical sources. The background can easily be higher than the signal itself, and thus any mission with the scientific goal of observing faint and/or extended sources in the X-ray band must deal with the background problem. ESA has recently selected "the hot and energetic universe" as science theme for the second large-class mission in the Cosmic Vision science program, to be pursued with an advanced X-ray observatory to be launched in 2028, and at present ATHENA is the proposal that is most likely to be selected for this slot. The mission is aimed to place an X-ray telescope in the L2 orbit equipped with an X-ray Integral Field Unit (X-IFU) based on high spectral resolution transition-edge microcalorimeters, and has among its goals the detection and characterization of high-redshift active galactic nuclei (AGNs), cluster of galaxies and their outskirts, which is why great care must be taken to reduce the background impact on the detection/characterization of these sources. Aims: The background is composed of a diffuse component and an internal particle component for any satellite operating in the X-ray band. We take as reference the X-ray IFU instrument that will be placed onboard the ATHENA mission to analyze both these components and their variability for different orbits, observational conditions and/or design choices. We also show how different background levels affect the instrumental performance, and the scientific results obtainable with the instrument in the best configuration. The X-IFUis a cryogenic X-ray spectrometer, based on a large array of 3840 transition-edge sensors (TES) of 250 μm side, with a spectral energy resolution of 2.5 eVin the 0.2-10 keVenergy band, over a field of view of 5 × 5 arcmin2, high count rate capability and a 5 arcsec angular resolution. Methods: There are no experimental data about the background experienced by

  17. Music and Moral Judgment: The Effect of Background Music on the Evaluation of Ads Promoting Unethical Behavior

    ERIC Educational Resources Information Center

    Ziv, Naomi; Hoftman, Moran; Geyer, Mor

    2012-01-01

    Background music is often used in ads as a means of persuasion. Previous research has studied the effect of music in advertising using neutral or uncontroversial products. The aim of the studies reported here was to examine the effect of music on the perception of products promoting unethical behavior. Each of the series of three studies described…

  18. Effects of durum wheat background on the expression of hexaploid wheat-derived Fusarium head blight resistance genes

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Multiple Fusarium head blight (FHB) resistance sources have been identified in common wheat, but an effective source of resistance to FHB has not found in durum wheat. Here we report preliminary results on the effects of durum background on the expression of hexaploid wheat-derived FHB resistance g...

  19. Geometrical correction of the e-beam proximity effect for raster scan systems

    NASA Astrophysics Data System (ADS)

    Belic, Nikola; Eisenmann, Hans; Hartmann, Hans; Waas, Thomas

    1999-06-01

    Increasing demands on pattern fidelity and CD accuracy in e- beam lithography require a correction of the e-beam proximity effect. The new needs are mainly coming from OPC at mask level and x-ray lithography. The e-beam proximity limits the achievable resolution and affects neighboring structures causing under- or over-exposion depending on the local pattern densities and process settings. Methods to compensate for this unequilibrated does distribution usually use a dose modulation or multiple passes. In general raster scan systems are not able to apply variable doses in order to compensate for the proximity effect. For system of this kind a geometrical modulation of the original pattern offers a solution for compensation of line edge deviations due to the proximity effect. In this paper a new method for the fast correction of the e-beam proximity effect via geometrical pattern optimization is described. The method consists of two steps. In a first step the pattern dependent dose distribution caused by back scattering is calculated by convolution of the pattern with the long range part of the proximity function. The restriction to the long range part result in a quadratic sped gain in computing time for the transformation. The influence of the short range part coming from forward scattering is not pattern dependent and can therefore be determined separately in a second step. The second calculation yields the dose curve at the border of a written structure. The finite gradient of this curve leads to an edge displacement depending on the amount of underground dosage at the observed position which was previously determined in the pattern dependent step. This unintended edge displacement is corrected by splitting the line into segments and shifting them by multiples of the writers address grid to the opposite direction.

  20. Finite-basis correction applied to the optimized effective potential within the FLAPW method

    NASA Astrophysics Data System (ADS)

    Friedrich, Christoph; Betzinger, Markus; Blügel, Stefan

    2011-03-01

    The optimized-effective-potential (OEP) method is a special technique to construct local exchange-correlation (xc) potentials from general orbital-dependent xc energy functionals for density-functional theory. Recently, we showed that particular care must be taken to construct local potentials within the all-electron full-potential augmented-plane-wave (FLAPW) approach. In fact, we found that the LAPW basis had to be converged to an accuracy that was far beyond that in calculations using conventional functionals, leading to a very high computational cost. This could be traced back to the convergence behavior of the density response function: only a highly converged basis lends the density enough flexibility to react adequately to changes of the potential. In this work we derive a numerical correction for the response function, which vanishes in the limit of an infinite, complete basis. It is constructed in the atomic spheres from the response of the basis functions themselves to changes of the potential. We show that such a finite-basis correction reduces the computational demand of OEP calculations considerably. We also discuss a similar correction scheme for GW calculations.

  1. A Monte Carlo correction for the effect of Compton scattering in 3-D PET brain imaging

    SciTech Connect

    Levin, C.S.; Dahlbom, M.; Hoffman, E.J.

    1995-08-01

    A Monte Carlo simulation has been developed to simulate and correct for the effect of Compton scatter in 3-D acquired PET brain scans. The method utilizes the 3-D reconstructed image volume as the source intensity distribution for a photon-tracking Monte Carlo simulation. It is assumed that the number of events in each pixel of the image represents the isotope concentration at that location in the brain. The history of each annihilation photon`s interactions in the scattering medium is followed, and the sinograms for the scattered and unscattered photon pairs are generated in a simulated 3-D PET acquisition. The calculated scatter contribution is used to correct the original data set. The method is general and can be applied to any scanner configuration or geometry. In its current form the simulation requires 25 hours on a single Sparc 10 CPU when every pixel in a 15-plane, 128 x 128 pixel image volume is sampled, and less than 2 hours when 16 pixels (4 x 4) are grouped as a single pixel. Results of the correction applied to 3-D human and phantom studies are presented.

  2. Image-based correction of the light dilution effect for SO2 camera measurements

    NASA Astrophysics Data System (ADS)

    Campion, Robin; Delgado-Granados, Hugo; Mori, Toshiya

    2015-07-01

    Ultraviolet SO2 cameras are increasingly used in volcanology because of their ability to remotely measure the 2D distribution of SO2 in volcanic plumes, at a high frequency. However, light dilution, i.e., the scattering of ambient photons within the instrument's field of view (FoV) on air parcels located between the plume and the instrument, induces a systematic underestimation of the measurements, whose magnitude increases with distance, SO2 content, atmospheric pressure and turbidity. Here we describe a robust and straightforward method to quantify and correct this effect. We retrieve atmospheric scattering coefficients based on the contrast attenuation between the sky and the increasingly distant slope of the volcanic edifice. We illustrate our method with a case study at Etna volcano, where difference between corrected and uncorrected emission rates amounts to 40% to 80%, and investigate the temporal variations of the scattering coefficient during 1 h of measurements on Etna. We validate the correction method at Popocatépetl volcano by performing measurements of the same plume at different distances from the volcano. Finally, we reported the atmospheric scattering coefficients for several volcanoes at different latitudes and altitudes.

  3. Bayesian Correction of Misclassification of Pertussis in Vaccine Effectiveness Studies: How Much Does Underreporting Matter?

    PubMed

    Goldstein, Neal D; Burstyn, Igor; Newbern, E Claire; Tabb, Loni P; Gutowski, Jennifer; Welles, Seth L

    2016-06-01

    Diagnosis of pertussis remains a challenge, and consequently research on the risk of disease might be biased because of misclassification. We quantified this misclassification and corrected for it in a case-control study of children in Philadelphia, Pennsylvania, who were 3 months to 6 years of age and diagnosed with pertussis between 2011 and 2013. Vaccine effectiveness (VE; calculated as (1 - odds ratio) × 100) was used to describe the average reduction in reported pertussis incidence resulting from persons being up to date on pertussis-antigen containing vaccines. Bayesian techniques were used to correct for purported nondifferential misclassification by reclassifying the cases per the 2014 Council of State and Territorial Epidemiologists pertussis case definition. Naïve VE was 50% (95% confidence interval: 16%, 69%). After correcting for misclassification, VE ranged from 57% (95% credible interval: 30, 73) to 82% (95% credible interval: 43, 95), depending on the amount of underreporting of pertussis that was assumed to have occurred in the study period. Meaningful misclassification was observed in terms of false negatives detected after the incorporation of infant apnea to the 2014 case definition. Although specificity was nearly perfect, sensitivity of the case definition varied from 90% to 20%, depending on the assumption about missed cases. Knowing the degree of the underreporting is essential to the accurate evaluation of VE. PMID:27188939

  4. The Effect of Background Music in Shark Documentaries on Viewers' Perceptions of Sharks

    PubMed Central

    Hastings, Philip A.; Gneezy, Ayelet

    2016-01-01

    Despite the ongoing need for shark conservation and management, prevailing negative sentiments marginalize these animals and legitimize permissive exploitation. These negative attitudes arise from an instinctive, yet exaggerated fear, which is validated and reinforced by disproportionate and sensationalistic news coverage of shark ‘attacks’ and by highlighting shark-on-human violence in popular movies and documentaries. In this study, we investigate another subtler, yet powerful factor that contributes to this fear: the ominous background music that often accompanies shark footage in documentaries. Using three experiments, we show that participants rated sharks more negatively and less positively after viewing a 60-second video clip of swimming sharks set to ominous background music, compared to participants who watched the same video clip set to uplifting background music, or silence. This finding was not an artifact of soundtrack alone because attitudes toward sharks did not differ among participants assigned to audio-only control treatments. This is the first study to demonstrate empirically that the connotative attributes of background music accompanying shark footage affect viewers’ attitudes toward sharks. Given that nature documentaries are often regarded as objective and authoritative sources of information, it is critical that documentary filmmakers and viewers are aware of how the soundtrack can affect the interpretation of the educational content. PMID:27487003

  5. Effective Strategies for Academic Success among African American Male Student Athletes from Low Socioeconomic Backgrounds

    ERIC Educational Resources Information Center

    Smith, Marisha R.

    2012-01-01

    The purpose of this study was to identify contributing factors for academic success among African American male student athletes from low socioeconomic backgrounds. Life narrative analysis was used in this qualitative study. The researcher conducted in-depth individual interviews with 7 African American males who attended college on athletic…

  6. Effects of Background Noise on Cortical Encoding of Speech in Autism Spectrum Disorders

    ERIC Educational Resources Information Center

    Russo, Nicole; Zecker, Steven; Trommer, Barbara; Chen, Julia; Kraus, Nina

    2009-01-01

    This study provides new evidence of deficient auditory cortical processing of speech in noise in autism spectrum disorders (ASD). Speech-evoked responses (approximately 100-300 ms) in quiet and background noise were evaluated in typically-developing (TD) children and children with ASD. ASD responses showed delayed timing (both conditions) and…

  7. Effect of backgrounding system on feedlot performance and carcass characteristics of beef steers

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The objective of this study was to evaluate feedlot performance and carcass characteristics of steers that were backgrounded using 1 of 3 treatments: 1) corn residue grazing supplemented 6 days a week with 2.77 kg DM/hd of distillers (CRD), 2) oat-brassica forage grazing (OBF) or 3) drylotting on a ...

  8. The Effect of Background Muscle Activity on Computerized Detection of sEMG Onset and Offset

    PubMed Central

    Lee, Angela S.; Cholewicki, Jacek; Reeves, N. Peter

    2007-01-01

    The performance of two computerized algorithms for the detection of muscle onset and offset was compared. Standard deviation (SD) method, a commonly used algorithm, and approximated generalized likelihood ratio (AGLR) method, a more recently developed algorithm, were evaluated at different levels of background surface EMG (sEMG) activity. For this purpose, the amplitude ratio between the period of muscle inactivity and activity was varied from 0.125 to 1 in artificially assembled sEMG traces. In addition, 1230 real sEMG signals, obtained from various trunk muscles, were raised to a power of 3 to change the relative amplitude ratio. As the relative level of background activity increased, both the SD and AGLR methods produced longer latencies and detected fewer muscle responses, suggesting that a detection artifact can be introduced if the subject populations being compared have different levels of background muscle activity. Of the two methods, AGLR appears to be the least affected by background activity. However, above the ratio 0.8, results from AGLR are also unreliable particularly in detecting offsets. Average latency artifacts near this ratio were 8 ms for AGLR and 46 ms for SD. PMID:17588589

  9. Effects of the Teacher's Background on Teaching and Students' Achievement in Botany and Zoology

    ERIC Educational Resources Information Center

    Tamir, P.

    1976-01-01

    The relationship of certain teacher background variables to their attitudes priorities, expectations, and instructional practices regarding botany and zoology was investigated. Teachers were grouped into three categories: botanists, zoologists, and neutrals; the academic achievement of the students of the teachers in the three categories was…

  10. Limb Looking: The effects of background subtraction on the temperature of SXT loops.

    NASA Astrophysics Data System (ADS)

    Medlin, D. A.; Blevins, H. T.; Schmelz, J. T.

    2003-05-01

    Knowing the temperature distribution along a loop is one possible test for the coronal heating models. The matter of how background subtraction may or may not affect the temperature distribution of loops could also play a crucial role in this analysis. Several instruments are currently available for loop studies, and numerous techniques are used to determine the temperature distributions along the loops. This has lead to many different, and mostly conflicting temperature results. We have chosen the Soft X-ray Telescope (SXT), aboard the Japanese satellite Yohkoh, for this study. The SXT data archives were searched for possible loop candidates. A set of loops on the limb, as well as a set of loops on the disk, were chosen for analysis. Temperature maps were generated for each loop with and without background subtraction. For each loop, we used both a uniform background subtraction as well as a pixel-by-pixel background subtraction. Once the temperature as a function of arc length has been found, it is then compared to the predictions made by different models. The Solar physics research at the University of Memphis is supported by NASA grants NAG5-9783 and NAG5-12096.

  11. The Effect of Background Music in Shark Documentaries on Viewers' Perceptions of Sharks.

    PubMed

    Nosal, Andrew P; Keenan, Elizabeth A; Hastings, Philip A; Gneezy, Ayelet

    2016-01-01

    Despite the ongoing need for shark conservation and management, prevailing negative sentiments marginalize these animals and legitimize permissive exploitation. These negative attitudes arise from an instinctive, yet exaggerated fear, which is validated and reinforced by disproportionate and sensationalistic news coverage of shark 'attacks' and by highlighting shark-on-human violence in popular movies and documentaries. In this study, we investigate another subtler, yet powerful factor that contributes to this fear: the ominous background music that often accompanies shark footage in documentaries. Using three experiments, we show that participants rated sharks more negatively and less positively after viewing a 60-second video clip of swimming sharks set to ominous background music, compared to participants who watched the same video clip set to uplifting background music, or silence. This finding was not an artifact of soundtrack alone because attitudes toward sharks did not differ among participants assigned to audio-only control treatments. This is the first study to demonstrate empirically that the connotative attributes of background music accompanying shark footage affect viewers' attitudes toward sharks. Given that nature documentaries are often regarded as objective and authoritative sources of information, it is critical that documentary filmmakers and viewers are aware of how the soundtrack can affect the interpretation of the educational content. PMID:27487003

  12. The Cow on the High Street: Effects of Background Context on Early Naming

    ERIC Educational Resources Information Center

    Meints, Kerstin; Plunkett, Kim; Harris, Paul L.; Dimmock, Debbie

    2004-01-01

    What role does contextual information play in children's early word comprehension? Using an inter-modal preferential looking task, we investigated how different background contexts influence children's looking times before and after an image has been named. Prior to the experiment, early comprehension of words was assessed using parental…

  13. Mammographic density descriptors of novel phantom images: effect of clustered lumpy backgrounds

    NASA Astrophysics Data System (ADS)

    Li, Yanpeng; Brennan, Patrick C.; Ryan, Elaine

    2014-03-01

    Mammographic breast density (MBD) is a risk factor for breast cancer. Both qualitative and quantitative methods have been used to evaluate MBD. However as it is impossible to measure the actual weight or volume of fibroglandular tissue evident on a mammogram, therefore it is hard to know the true correlation between measured mammographic density and the fibroglandular tissue volume. A phantom system has been developed that represents glandular tissue within an adipose tissue structure. Although a previous study has found strong correlation between the synthesised glandular mass and several image descriptors, it is not known if the correlation is still present when a high level of background noise is introduced. The background noise is required to more realistically simulate clinical image appearance. The aim of this study is to investigate if the correlation between percentage density, integrated density, and standard deviation of mean grey value of the whole phantom and simulated glandular tissue mass is affected by background noise being added to the phantom images. For a set of one hundred phantom mammographic images, clustered lumpy backgrounds were synthesised and superimposed onto phantom images. The correlation between the synthesised glandular mass and the image descriptors were calculated. The results showed the correlation is strong and statistically significant for the above three descriptors with r is 0.7597, 0.8208, and 0.7167 respectively. This indicates these descriptors may be used to assess breast fibroglandular tissue content of the breast using mammographic images.

  14. An unbiased measurement of the UV background and its evolution via the proximity effect in quasar spectra

    NASA Astrophysics Data System (ADS)

    Dall'Aglio, A.; Wisotzki, L.; Worseck, G.

    2008-11-01

    We investigated a set of high-resolution (R˜45 000), high signal-to-noise (S/N˜70) quasar spectra to search for the signature of the so-called proximity effect in the H I Lyα forest. The sample consists of 40 bright quasars with redshifts in the range 2.1 < z < 4.7. Using the flux transmission statistic, we determined the redshift evolution of the H I effective optical depth in the Lyman forest between 2⪉ z⪉ 4.5, finding good agreement with previous measurements based on smaller samples. We also see the previously reported dip in τ_eff(z) around redshift z˜ 3.3, but as the significance of that feature is only 2.6σ, we consider this detection tentative. Comparing the flux transmission near each quasar with what was expected from the overall trend of τ_eff(z), we clearly detect the proximity effect not only in the combined quasar sample, but also towards each individual line of sight at high significance, albeit with varying strength. We quantify this strength using a simple prescription based on a fiducial value for the intensity of the metagalactic UV background (UVB) radiation field at 1 Ryd, multiplied by a free parameter that varies from QSO to QSO. The observed proximity effect strength distribution (PESD) is asymmetric, with an extended tail towards values corresponding to a weak effect. We demonstrate that this is not simply an effect of gravitational clustering around quasars, as the same asymmetry is already present in the PESD predicted for purely Poissonian variance in the absorption lines. We present the results of running the same analysis on simulated quasar spectra generated by a simple Monte-Carlo code. Comparing the simulated PESD with observations, we argue that the standard method of determining the UVB intensity Jν_0 by averaging over several lines of sight is heavily biased towards high values of Jν_0 because of the PESD asymmetry. Using instead the mode of the PESD provides an estimate of Jν_0 that is unbiased with respect to his

  15. Classification of ring artifacts for their effective removal using type adaptive correction schemes.

    PubMed

    Anas, Emran Mohammad Abu; Lee, Soo Yeol; Hasan, Kamrul

    2011-06-01

    High resolution tomographic images acquired with a digital X-ray detector are often degraded by the so called ring artifacts. In this paper, a detail analysis including the classification, detection and correction of these ring artifacts is presented. At first, a novel idea for classifying rings into two categories, namely type I and type II rings, is proposed based on their statistical characteristics. The defective detector elements and the dusty scintillator screens result in type I ring and the mis-calibrated detector elements lead to type II ring. Unlike conventional approaches, we emphasize here on the separate detection and correction schemes for each type of rings for their effective removal. For the detection of type I ring, the histogram of the responses of the detector elements is used and a modified fast image inpainting algorithm is adopted to correct the responses of the defective pixels. On the other hand, to detect the type II ring, first a simple filtering scheme is presented based on the fast Fourier transform (FFT) to smooth the sum curve derived form the type I ring corrected projection data. The difference between the sum curve and its smoothed version is then used to detect their positions. Then, to remove the constant bias suffered by the responses of the mis-calibrated detector elements with view angle, an estimated dc shift is subtracted from them. The performance of the proposed algorithm is evaluated using real micro-CT images and is compared with three recently reported algorithms. Simulation results demonstrate superior performance of the proposed technique as compared to the techniques reported in the literature. PMID:21513928

  16. The spherical terrain correction and its effect on the gravimetric-isostatic Moho determination

    NASA Astrophysics Data System (ADS)

    Abrehdary, M.; Sjöberg, L. E.; Bagherbandi, M.

    2016-01-01

    In this study, the Moho depth is estimated based on the refined spherical Bouguer gravity disturbance and DTM2006 topographic data using the Vening Meinesz-Moritz gravimetric-isostatic hypothesis. In this context, we compute the refined spherical Bouguer gravity disturbances in a set of 1° × 1° blocks. The spherical terrain correction, a residual correction to each Bouguer shell, is computed using rock heights and ice sheet thicknesses from the DTM2006 and Earth2014 models. The study illustrates that the defined simple Bouguer gravity disturbance corrected for the density variations of the oceans, ice sheets and sediment basins and also the non-isostatic effects needs a significant terrain correction to become the refined Bouguer gravity disturbance, and that the isostatic gravity disturbance is significantly better defined by the latter disturbance plus a compensation attraction. Our study shows that despite the fact that the lateral variation of the crustal depth is rather smooth, the terrain affects the result most significantly in many areas. The global numerical results show that the estimated Moho depths by the simple and refined spherical Bouguer gravity disturbances and the seismic CRUST1.0 model agree to 5.6 and 2.7 km in RMS, respectively. Also, the mean value differences are 1.7 and 0.2 km, respectively. Two regional numerical studies show that the RMS differences between the Moho depths estimated based on the simple and refined spherical Bouguer gravity disturbance and that using CRUST1.0 model yield fits of 4.9 and 3.2 km in South America and yield 3.2 and 3.4 km in Fennoscandia, respectively.

  17. Influence of background noise on the performance in the odor sensitivity task: effects of noise type and extraversion.

    PubMed

    Seo, Han-Seok; Hähner, Antje; Gudziol, Volker; Scheibe, Mandy; Hummel, Thomas

    2012-10-01

    Recent research demonstrated that background noise relative to silence impaired subjects' performance in a cognitively driven odor discrimination test. The current study aimed to investigate whether the background noise can also modulate performance in an odor sensitivity task that is less cognitively loaded. Previous studies have shown that the effect of background noise on task performance can be different in relation to degree of extraversion and/or type of noise. Accordingly, we wanted to examine whether the influence of background noise on the odor sensitivity task can be altered as a function of the type of background noise (i.e., nonverbal vs. verbal noise) and the degree of extraversion (i.e., introvert vs. extrovert group). Subjects were asked to conduct an odor sensitivity task in the presence of either nonverbal noise (e.g., party sound) or verbal noise (e.g., audio book), or silence. Overall, the subjects' mean performance in the odor sensitivity task was not significantly different across three auditory conditions. However, with regard to the odor sensitivity task, a significant interaction emerged between the type of background noise and the degree of extraversion. Specifically, verbal noise relative to silence significantly impaired or improved the performance of the odor sensitivity task in the introvert or extrovert group, respectively; the differential effect of introversion/extraversion was not observed in the nonverbal noise-induced task performance. In conclusion, our findings provide new empirical evidence that type of background noise and degree of extraversion play an important role in modulating the effect of background noise on subjects' performance in an odor sensitivity task. PMID:22941357

  18. Effect of quantum correction on nonlinear thermal wave of electrons driven by laser heating

    NASA Astrophysics Data System (ADS)

    Nafari, F.; Ghoranneviss, M.

    2016-08-01

    In thermal interaction of laser pulse with a deuterium-tritium (DT) plane, the thermal waves of electrons are generated instantly. Since the thermal conductivity of electron is a nonlinear function of temperature, a nonlinear heat conduction equation is used to investigate the propagation of waves in solid DT. This paper presents a self-similar analytic solution for the nonlinear heat conduction equation in a planar geometry. The thickness of the target material is finite in numerical computation, and it is assumed that the laser energy is deposited at a finite initial thickness at the initial time which results in a finite temperature for electrons at initial time. Since the required temperature range for solid DT ignition is higher than the critical temperature which equals 35.9 eV, the effects of quantum correction in thermal conductivity should be considered. This letter investigates the effects of quantum correction on characteristic features of nonlinear thermal wave, including temperature, penetration depth, velocity, heat flux, and heating and cooling domains. Although this effect increases electron temperature and thermal flux, penetration depth and propagation velocity are smaller. This effect is also applied to re-evaluate the side-on laser ignition of uncompressed DT.

  19. Effects of Error Correction during Assessment Probes on the Acquisition of Sight Words for Students with Moderate Intellectual Disabilities

    ERIC Educational Resources Information Center

    Waugh, Rebecca E.

    2010-01-01

    Simultaneous prompting is an errorless learning strategy designed to reduce the number of errors students make; however, research has shown a disparity in the number of errors students make during instructional versus probe trials. This study directly examined the effects of error correction versus no error correction during probe trials on the…

  20. Effects of Error Correction during Assessment Probes on the Acquisition of Sight Words for Students with Moderate Intellectual Disabilities

    ERIC Educational Resources Information Center

    Waugh, Rebecca E.; Alberto, Paul A.; Fredrick, Laura D.

    2011-01-01

    Simultaneous prompting is an errorless learning strategy designed to reduce the number of errors students make; however, research has shown a disparity in the number of errors students make during instructional versus probe trials. This study directly examined the effects of error correction versus no error correction during probe trials on the…

  1. On Neglecting Chemical Exchange Effects When Correcting in Vivo 31P MRS Data for Partial Saturation

    NASA Astrophysics Data System (ADS)

    Ouwerkerk, Ronald; Bottomley, Paul A.

    2001-02-01

    Signal acquisition in most MRS experiments requires a correction for partial saturation that is commonly based on a single exponential model for T1 that ignores effects of chemical exchange. We evaluated the errors in 31P MRS measurements introduced by this approximation in two-, three-, and four-site chemical exchange models under a range of flip-angles and pulse sequence repetition times (TR) that provide near-optimum signal-to-noise ratio (SNR). In two-site exchange, such as the creatine-kinase reaction involving phosphocreatine (PCr) and γ-ATP in human skeletal and cardiac muscle, errors in saturation factors were determined for the progressive saturation method and the dual-angle method of measuring T1. The analysis shows that these errors are negligible for the progressive saturation method if the observed T1 is derived from a three-parameter fit of the data. When T1 is measured with the dual-angle method, errors in saturation factors are less than 5% for all conceivable values of the chemical exchange rate and flip-angles that deliver useful SNR per unit time over the range T1/5 ≤ TR ≤ 2T1. Errors are also less than 5% for three- and four-site exchange when TR ≥ T1*/2, the so-called "intrinsic" T1's of the metabolites. The effect of changing metabolite concentrations and chemical exchange rates on observed T1's and saturation corrections was also examined with a three-site chemical exchange model involving ATP, PCr, and inorganic phosphate in skeletal muscle undergoing up to 95% PCr depletion. Although the observed T1's were dependent on metabolite concentrations, errors in saturation corrections for TR = 2 s could be kept within 5% for all exchanging metabolites using a simple interpolation of two dual-angle T1 measurements performed at the start and end of the experiment. Thus, the single-exponential model appears to be reasonably accurate for correcting 31P MRS data for partial saturation in the presence of chemical exchange. Even in systems where

  2. Effects of adopting new precession, nutation and equinox corrections on the terrestrial reference frame

    NASA Technical Reports Server (NTRS)

    Zhu, S. Y.; Mueller, I. I.

    1982-01-01

    The effect of adopting definitive precession and equinox corrections on the terrestrial reference frame was investigated. It is noted that the effect on polar motion is a diurnal periodic term with an amplitude increasing linearly in time whole on UT1 it is a linear term: general principles are given to determine the effects of small rotations of the frame of a conventional inertial reference system (CIS) on the frame of the conventional terrestrial reference system (CTS); seven CTS options are presented, one of which is necessary to accommodate such rotation. Accommodating possible future changes in the astronomical nutation is discussed. The effects of differences which may exist between the various CTS's and CIS's on Earth rotation parameters (ERP) and how these differences can be determined are examined. It is shown that the CTS differences can be determined from observations made at the same site. The CIS differences by comparing the ERP's are determined by the different techniques during the same time period.

  3. Aliasing Effects of Q-bursts on Background Spectra of Schumann Resonances

    NASA Astrophysics Data System (ADS)

    Guha, A.; Mushtak, V. C.; Williams, E.; Neska, M.; Nagy, T. G.; Satori, G.

    2013-12-01

    The Earth's Schumann resonances (SR) manifest as a 'background' signal and as an occasional transient excitation (Q-burst) of substantially larger amplitude. The background signal is generally attributed to the superposition of radiated ELF signal from average lightning flashes originating in convective scale thunderstorms predominant in the late afternoon, and whose waveforms are all overlapping. The larger transient excitations are attributed to exceptionally energetic lightning flashes in larger mesoscale convective systems. These flashes stand out strongly against the background signal, and often produce sprites in the mesosphere. These exceptional events are often delayed in the diurnal cycle by many hours into the evening and even the early morning over land areas. This study is concerned with the idea that the spectral energy of a single transient event can compete with the background energy over 5-15 minute time scales, and so serve to alias the background spectrum and destroy that 'fingerprint' for the geographical origin of the background lightning. In the present work, an attempt is made to detect these large by simultaneous observation of SR electric field spectra from two stations in Europe, Belsk, Poland (BLK: 49.190 N, 22.550 E) and Nagycenk, Hungary (NCK: 47.60 N, 16.70 E), separated by 0.47 Mm, along with the same strokes identified by the World Wide Lighting Location Network (WWLLN). First, the energy contents (EC) for each five second spectra with up to four SR modes for the two stations are computed. Q-burst events are selected if: (1) the Core Standard Deviation (CSD) in any 5 second segment is above 16 CSD (2) the ratio of CSDs at both stations is within 0.5 to 2, and (3) the event occurs within 1-3 time samples at each station. Simultaneous observations at these nearby stations enable us to distinguish the cultural noise and lightning strokes originating close to each station. At the same time, the propagation path form the originating Q

  4. Small field detector correction factors: effects of the flattening filter for Elekta and Varian linear accelerators.

    PubMed

    Tyler, Madelaine K; Liu, Paul Z Y; Lee, Christopher; McKenzie, David R; Suchowerska, Natalka

    2016-01-01

    Flattening filter-free (FFF) beams are becoming the preferred beam type for stereotactic radiosurgery (SRS) and stereotactic ablative radiation therapy (SABR), as they enable an increase in dose rate and a decrease in treatment time. This work assesses the effects of the flattening filter on small field output factors for 6 MV beams generated by both Elekta and Varian linear accelerators, and determines differences between detector response in flattened (FF) and FFF beams. Relative output factors were measured with a range of detectors (diodes, ionization cham-bers, radiochromic film, and microDiamond) and referenced to the relative output factors measured with an air core fiber optic dosimeter (FOD), a scintillation dosimeter developed at Chris O'Brien Lifehouse, Sydney. Small field correction factors were generated for both FF and FFF beams. Diode measured detector response was compared with a recently published mathematical relation to predict diode response corrections in small fields. The effect of flattening filter removal on detector response was quantified using a ratio of relative detector responses in FFF and FF fields for the same field size. The removal of the flattening filter was found to have a small but measurable effect on ionization chamber response with maximum deviations of less than ± 0.9% across all field sizes measured. Solid-state detectors showed an increased dependence on the flattening filter of up to ± 1.6%. Measured diode response was within ± 1.1% of the published mathematical relation for all fields up to 30 mm, independent of linac type and presence or absence of a flattening filter. For 6 MV beams, detector correction factors between FFF and FF beams are interchangeable for a linac between FF and FFF modes, providing that an additional uncertainty of up to ± 1.6% is accepted. PMID:27167280

  5. The effect of ambient pressure on well chamber response: experimental results with empirical correction factors.

    PubMed

    Griffin, S L; DeWerd, L A; Micka, J A; Bohm, T D

    2005-03-01

    For some air-communicating well-type chambers used for low-energy brachytherapy source assay, deviations from expected values of measured air kerma strength were observed at low pressures associated with high altitudes. This effect is consistent with an overcompensation by the air density correction to standard atmospheric temperature and pressure (P(TP)). This work demonstrates that the P(TP) correction does not fully compensate for the high altitude pressure effects that are seen with air-communicating chambers at low photon energies in the range of 20-100 keV. Deviations of up to 18% at a pressure corresponding to an approximate elevation of 8500 ft for photon energies of 20 keV are possible. For high-energy photons and for high-energy beta emitters in air-communicating chambers the P(TP) factor is applicable. As expected, the ambient pressure does not significantly affect the response of pressurized well chambers (within 1%) to either low- or high-energy photons. However, when used with beta emitters, pressurized chambers appear to exhibit a slight dependence on the ambient pressure. Using measured data, the response and correction factors were determined for three models of air-communicating well chambers for low-energy photon sources at various pressures corresponding to elevations above sea level. Monte Carlo calculations were also performed which were correlated with the experimental findings. A more complete study of the Monte Carlo calculations is presented in the accompanying paper, "The effect of ambient pressure on well chamber response: Monte Carlo calculated results for the HDR1000 Plus." PMID:15839341

  6. A Comparative Dosimetric Analysis of the Effect of Heterogeneity Corrections Used in Three Treatment Planning Algorithms

    NASA Astrophysics Data System (ADS)

    Herrick, Andrea Celeste

    Successful treatment in radiation oncology relies on the evaluation of a plan for each individual patient based on delivering the maximum dose to the tumor while sparing the surrounding normal tissue (organs at risk) in the patient. Organs at risk (OAR) typically considered include the heart, the spinal cord, healthy lung tissue, and any other organ in the vicinity of the target that is not affected by the disease being treated. Depending on the location of the tumor and its proximity to these OARs, several plans may be created and evaluated in order to assess which "solution" most closely meets all of the specified criteria. In order to successfully review a treatment plan and take the correct course of action, a physician needs to rely on the computer model (treatment planning algorithm) of dose distribution to reconstruct CT scan data to proceed with the plan that best achieves all of the goals. There are many available treatment planning systems from which a Radiation Oncology center can choose from. While the radiation interactions considered are identical among clinics, the way the chosen algorithm handles these interactions can vary immensely. The goal of this study was to provide a comparison between two commonly used treatment planning systems (Pinnacle and Eclipse) and their associated dose calculation algorithms. In order to this, heterogeneity correction models were evaluated via test plans, and the effects of going from heterogeneity uncorrected patient representation to a heterogeneity correction representation were studied. The results of this study indicate that the actual dose delivered to the patient varies greatly between treatment planning algorithms in areas of low density tissue such as in the lungs. Although treatment planning algorithms are attempting to come to the same result with heterogeneity corrections, the reality is that the results depend strongly on the algorithm used in the situations studied. While the Anisotropic Analytic Method

  7. Temperature effects on pitfall catches of epigeal arthropods: a model and method for bias correction.

    PubMed

    Saska, Pavel; van der Werf, Wopke; Hemerik, Lia; Luff, Martin L; Hatten, Timothy D; Honek, Alois; Pocock, Michael

    2013-02-01

    Carabids and other epigeal arthropods make important contributions to biodiversity, food webs and biocontrol of invertebrate pests and weeds. Pitfall trapping is widely used for sampling carabid populations, but this technique yields biased estimates of abundance ('activity-density') because individual activity - which is affected by climatic factors - affects the rate of catch. To date, the impact of temperature on pitfall catches, while suspected to be large, has not been quantified, and no method is available to account for it. This lack of knowledge and the unavailability of a method for bias correction affect the confidence that can be placed on results of ecological field studies based on pitfall data.Here, we develop a simple model for the effect of temperature, assuming a constant proportional change in the rate of catch per °C change in temperature, r, consistent with an exponential Q10 response to temperature. We fit this model to 38 time series of pitfall catches and accompanying temperature records from the literature, using first differences and other detrending methods to account for seasonality. We use meta-analysis to assess consistency of the estimated parameter r among studies.The mean rate of increase in total catch across data sets was 0·0863 ± 0·0058 per °C of maximum temperature and 0·0497 ± 0·0107 per °C of minimum temperature. Multiple regression analyses of 19 data sets showed that temperature is the key climatic variable affecting total catch. Relationships between temperature and catch were also identified at species level. Correction for temperature bias had substantial effects on seasonal trends of carabid catches.Synthesis and Applications. The effect of temperature on pitfall catches is shown here to be substantial and worthy of consideration when interpreting results of pitfall trapping. The exponential model can be used both for effect estimation and for bias correction of observed data. Correcting for temperature

  8. Correction of NIM-3A absolute gravimeter for self-attraction effect

    NASA Astrophysics Data System (ADS)

    Li, Chunjian; Xu, Jin-yi; Feng, Jin-yang; SU, Duo-wu; Wu, Shu-qing

    2015-02-01

    The mass of free-fall absolute gravimeter can produce vertical gravitational attraction to the free-falling test body during the measurement of acceleration due to gravity. The vertical gravitational attraction can cause an artificial deviation to the measured value of gravitational acceleration. This paper describes the operating principle of a free-fall absolute gravimeter and the method used to determine the reference height of a gravimeter. It also describes the physical structure of NIM-3A absolute gravimeter lately developed by National Institute of Metrology (China), and studies the correction of gravimeter for Self-attraction effect.

  9. Correcting the relationship between PRI and shadow fraction for the blue sky effect

    NASA Astrophysics Data System (ADS)

    Mõttus, Matti

    2016-04-01

    different locations inside the canopy and calculate a correction term for the canopy PRI estimates defined using top-of-canopy irradiances. We determine the maximum value of the correction term by sampling the most sunlit and shaded road surface locations adjacent to tree crowns. Results indicate that under the particular illumination-view geometry, irradiance variations decreased the canopy PRI by as much as 0.06. The correction depended only slightly on atmospheric correction parameters. Other than the blue sky effect, PRI showed no correlation with the shadow fraction, indicating a lack of down-regulation at the time of measurement.

  10. Loneliness of Older Immigrant Groups in Canada: Effects of Ethnic-Cultural Background.

    PubMed

    De Jong Gierveld, Jenny; Van der Pas, Suzan; Keating, Norah

    2015-09-01

    This study aimed to explore the loneliness of several groups of older immigrants in Canada compared to native-born older adults. Data from the Canadian General Social Survey, Cycle 22 (N older adults = 3,692) were used. The dependent variable is the 6 item De Jong Gierveld loneliness scale. Determinants of loneliness included country of birth, ethnic background (cultural context); belongingness (community context) and social networks (social context). Results showed that only some immigrant groups are significantly lonelier than older adults born in Canada. Immigrants with similar language and culture are not lonelier; while those from countries that differ in native language/culture are significantly higher on loneliness. Multivariate analyses showed the importance of cultural background, of composition of the network of relatives and friends, and of local participation and feelings of belonging to the Canadian society in explaining loneliness of older immigrants. PMID:25982532

  11. A dipole moment of the microwave background as a cosmological effect

    NASA Technical Reports Server (NTRS)

    Paczynski, Bohdan; Piran, Tsvi

    1990-01-01

    A spherically symmetrical Tolman-Bondi cosmological model is presented in which the curvature of space and the entropy variety with distance from the center. The dipole and quadrupole moments in the distribution of the microwave background radiation are calculated as a function of cosmic time and position of an observer, assuming that the distance to the horizon is much smaller than any characteristic scale in the model. The quadrupole moment is found to be affected mostly by the gradient in the curvature of space while the dipole moment is dominated by the gradient of entropy. The results indicate that the observed dipole in the microwave background may be cosmological in origin. Observational tests of this argument are suggested.

  12. A Study on Effect of Water Background on Canopy Spectral of Wetland Aquatic Plant.

    PubMed

    Liu, Guang; Tang, Peng; Cai Zhan-qing; Wang, Tian-tian; Xu, Jun-feng

    2015-10-01

    Aquatic vegetation is the core of the wetland ecosystem, and it's also the main factor influencing the wetland ecosystem functions. In recent years, satellite remote sensing technology has been widely used in the investigation, classification and protection fields of wetland vegetation resources. Because of its unique growth environment, aquatic vegetation, the canopy spectrum of aquatic vegetation will be affected by water background elements including air-water interface, plankton in the water, sediment content, transparency, water depth, sediment, and the other optically active ingredients. When the remote sensing technology for wetland aquatic vegetation canopy spectral studies, should be considered the growth environment differences between aquatic and terrestrial vegetation. However, previous studies did not get the attention it deserves. This paper choose a typical water plant (Iris tentorium Maxim) as the research object, simulate the growth environment of wetland aquatic plants, use the feature spectrometer measurements the spectral reflectance of Iris tentorium Maxim vegetation canopy under different water depth gradient background (400-2 400 nm). Experimental results show that there is a significant negative correlation between background water depth and Iris canopy reflectance. Visible light band absolute correlation coefficient is above 0.9, near infrared band absolute correlation coefficient is above 0.8. In visible light and near infrared band, with water depth increases, the Iris canopy reflectance decreases obviously. Finally based on the highest correlation band of visible light and near infrared region (505, 717, 1 075 and 2 383 nm) established the linear equation between background water depth and the canopy reflectance, obtained the related parameters. PMID:26904852

  13. Correction of the inertial effect resulting from a plate moving under low-friction conditions.

    PubMed

    Yang, Feng; Pai, Yi-Chung

    2007-01-01

    The purpose of the present study was to develop a set of equations that can be employed to remove the inertial effect introduced by the movable platform upon which a person stands during a slip induced in gait; this allows the real ground reaction force (GRF) and its center of pressure (COP) to be determined. Analyses were also performed to determine how sensitive the COP offsets were to the changes of the parameters in the equation that affected the correction of the inertial effect. In addition, the results were verified empirically using a low friction movable platform together with a stationary object, a pendulum, and human subjects during a slip induced during gait. Our analyses revealed that the amount of correction required for the inertial effect due to the movable component is affected by its mass and its center of mass (COM) position, acceleration, the friction coefficient, and the landing position of the foot relative to the COM. The maximum error in the horizontal component of the GRF was close to 0.09 (body weight) during the recovery from a slip in walking. When uncorrected, the maximum error in the COP measurement could reach as much as 4 cm. Finally, these errors were magnified in the joint-moment computation and propagated proximally, ranging from 0.2 to 1.0 Nm/body mass from the ankle to the hip. PMID:17306274

  14. Correction of the Electrical and Thermal Extrinsic Effects in Thermoelectric Measurements by the Harman Method.

    PubMed

    Kang, Min-Su; Roh, Im-Jun; Lee, Yun Goo; Baek, Seung-Hyub; Kim, Seong Keun; Ju, Byeong-Kwon; Hyun, Dow-Bin; Kim, Jin-Sang; Kwon, Beomjin

    2016-01-01

    Although the Harman method evaluates the thermoelectric figure-of-merit in a rapid and simple fashion, the accuracy of this method is affected by several electrical and thermal extrinsic factors that have not been thoroughly investigated. Here, we study the relevant extrinsic effects and a correction scheme for them. A finite element model simulates the electrical potential and temperature fields of a sample, and enables the detailed analysis of electrical and thermal transport. The model predicts that the measurement strongly depends on the materials, sample geometries, and contact resistance of the electrodes. To verify the model, we measure the thermoelectric properties of Bi2-Te3 based alloys with systematically varied sample geometries and either with a point or a surface current source. By comparing the model and experimental data, we understand how the measurement conditions determine the extrinsic effects, and, furthermore, able to extract the intrinsic thermoelectric properties. A correction scheme is proposed to eliminate the associated extrinsic effects for an accurate evaluation. This work will help the Harman method be more consistent and accurate and contribute to the development of thermoelectric materials. PMID:27197596

  15. Correction of the Electrical and Thermal Extrinsic Effects in Thermoelectric Measurements by the Harman Method

    PubMed Central

    Kang, Min-Su; Roh, Im-Jun; Lee, Yun Goo; Baek, Seung-Hyub; Kim, Seong Keun; Ju, Byeong-Kwon; Hyun, Dow-Bin; Kim, Jin-Sang; Kwon, Beomjin

    2016-01-01

    Although the Harman method evaluates the thermoelectric figure-of-merit in a rapid and simple fashion, the accuracy of this method is affected by several electrical and thermal extrinsic factors that have not been thoroughly investigated. Here, we study the relevant extrinsic effects and a correction scheme for them. A finite element model simulates the electrical potential and temperature fields of a sample, and enables the detailed analysis of electrical and thermal transport. The model predicts that the measurement strongly depends on the materials, sample geometries, and contact resistance of the electrodes. To verify the model, we measure the thermoelectric properties of Bi2-Te3 based alloys with systematically varied sample geometries and either with a point or a surface current source. By comparing the model and experimental data, we understand how the measurement conditions determine the extrinsic effects, and, furthermore, able to extract the intrinsic thermoelectric properties. A correction scheme is proposed to eliminate the associated extrinsic effects for an accurate evaluation. This work will help the Harman method be more consistent and accurate and contribute to the development of thermoelectric materials. PMID:27197596

  16. Effects of adenotonsillar hypertrophy corrective surgery on nocturnal enuresis of children

    PubMed Central

    Abdollohi-Fakhim, Shahin; Talebi, Arefeh; Naghavi-Behzad, Mohammad; Piri, Reza; Nazari, Mohammad Sadra

    2016-01-01

    Background: Nocturnal enuresis is considered a common urological complaint especially among children. Respiratory obstructive diseases have been one of the possible etiologies of such a condition. The most common type of upper respiratory obstructive diseases in childhood is adenotonsillar hypertrophy. In this study, it was tried to estimate the prevalence of nocturnal enuresis in adenotonsillar hypertrophy as an upper obstructive airway disease and cure rate after corrective operation. Materials and Methods: In this longitudinal study, 184 children with adenotonsillar hypertrophy as case group and 200 healthy children as control group were randomly compared for nocturnal enuresis incidence and risk factors. Then they were followed after 6 months to estimate the cure rate after corrective operation. Results: In case group, nocturnal enuresis was more common than control group (26% vs. 17%, P = 0.1). Factors which had a role in enuresis in case group were family history (P = 0.03) and male sex (P = 0.05). Three months after surgery, 48% of children totally cured from enuresis (P = 0.001) and 71% cured both partially or totally (P = 0.03). The response rate after moderate obstruction relieving was 100% while that in severe cases was 60% (P = 0.2). Conclusions: Nocturnal enuresis due to upper obstructive airway disease occurs more in male and in the presence of family history. The cure rate after 6 months of operation was more prominent in moderate obstruction which suggests enuresis in severe airway obstruction may need a longer time to subside. Cure rate of primary enuresis due to obstructive airway disease after 6 months of relieving was 48% in children over 5 years old. PMID:27185983

  17. Effects of collision between two plumes on plume expansion dynamics during pulsed laser ablation in background gas

    NASA Astrophysics Data System (ADS)

    Umezu, Ikurou; Sakamoto, Naomichi; Fukuoka, Hiroshi; Yokoyama, Yasuhiro; Nobuzawa, Koichiro; Sugimura, Akira

    2013-03-01

    Si and Ge targets were simultaneously irradiated by individual two pulsed lasers, and two plumes from the targets were collided head-on with expectation to prepare hybrid nanoparticles. We investigate effects of He background gas pressure on plume collision dynamics. Three characteristic behaviors of plume expansion dynamics are observed at low, middle, and high background gas pressure regions. Interaction between the two atomic species during plume expansion was small and the effect of collision was hardly observed at a low background gas pressure, 130 Pa, while spatial evolution of the plume was suppressed at middle pressure, 270 Pa, due to collision of the two plumes. At high pressure, 2700 Pa, plume expansion is suppressed by background gas and the effect of a direct collision of two plumes was small. These results indicate that plume collision dynamics, which governs nanoparticle formation, and the mixture of Si and Ge species can be varied by background gas pressure. The deposit near the center of two targets was nanoparticles that were composed of Si and Ge.

  18. Exaggerating psychopathology produces residual effects that are resistant to corrective feedback: an experimental demonstration.

    PubMed

    Merckelbach, Harald; Dandachi-FitzGerald, Brechje; van Mulken, Peter; Ponds, Rudolf; Niesten, Elly

    2015-01-01

    We explored the effects of feedback on symptom reporting. Two experimental groups (n=15 each) were given a scenario with the option to exaggerate symptoms. Compared with a control condition (n=15), both groups scored significantly higher on the Structured Inventory of Malingered Symptomatology. Next, one group was confronted in a sympathetic way about their symptom validity test failure, whereas the other group was confronted in a neutral manner. Both groups subsequently completed the Brief Symptom Inventory (BSI). BSI scores of both feedback groups remained significantly higher than those of control participants. Participants who had been provided with sympathetic feedback or neutral feedback did not differ in their BSI scores. Even participants who indicated during the exit interview that they had given up symptom exaggeration attained significantly higher BSI scores than those of controls, indicating that exaggeration has residual effects that are resistant to corrective feedback. We discuss cognitive dissonance as a model for understanding the residual effects of symptom exaggeration. PMID:25529587

  19. Assessing and Correcting Topographic Effects on Forest Canopy Height Retrieval Using Airborne LiDAR Data

    PubMed Central

    Duan, Zhugeng; Zhao, Dan; Zeng, Yuan; Zhao, Yujin; Wu, Bingfang; Zhu, Jianjun

    2015-01-01

    Topography affects forest canopy height retrieval based on airborne Light Detection and Ranging (LiDAR) data a lot. This paper proposes a method for correcting deviations caused by topography based on individual tree crown segmentation. The point cloud of an individual tree was extracted according to crown boundaries of isolated individual trees from digital orthophoto maps (DOMs). Normalized canopy height was calculated by subtracting the elevation of centres of gravity from the elevation of point cloud. First, individual tree crown boundaries are obtained by carrying out segmentation on the DOM. Second, point clouds of the individual trees are extracted based on the boundaries. Third, precise DEM is derived from the point cloud which is classified by a multi-scale curvature classification algorithm. Finally, a height weighted correction method is applied to correct the topological effects. The method is applied to LiDAR data acquired in South China, and its effectiveness is tested using 41 field survey plots. The results show that the terrain impacts the canopy height of individual trees in that the downslope side of the tree trunk is elevated and the upslope side is depressed. This further affects the extraction of the location and crown of individual trees. A strong correlation was detected between the slope gradient and the proportions of returns with height differences more than 0.3, 0.5 and 0.8 m in the total returns, with coefficient of determination R2 of 0.83, 0.76, and 0.60 (n = 41), respectively. PMID:26016907

  20. Assessing and correcting topographic effects on forest canopy height retrieval using airborne LiDAR data.

    PubMed

    Duan, Zhugeng; Zhao, Dan; Zeng, Yuan; Zhao, Yujin; Wu, Bingfang; Zhu, Jianjun

    2015-01-01

    Topography affects forest canopy height retrieval based on airborne Light Detection and Ranging (LiDAR) data a lot. This paper proposes a method for correcting deviations caused by topography based on individual tree crown segmentation. The point cloud of an individual tree was extracted according to crown boundaries of isolated individual trees from digital orthophoto maps (DOMs). Normalized canopy height was calculated by subtracting the elevation of centres of gravity from the elevation of point cloud. First, individual tree crown boundaries are obtained by carrying out segmentation on the DOM. Second, point clouds of the individual trees are extracted based on the boundaries. Third, precise DEM is derived from the point cloud which is classified by a multi-scale curvature classification algorithm. Finally, a height weighted correction method is applied to correct the topological effects. The method is applied to LiDAR data acquired in South China, and its effectiveness is tested using 41 field survey plots. The results show that the terrain impacts the canopy height of individual trees in that the downslope side of the tree trunk is elevated and the upslope side is depressed. This further affects the extraction of the location and crown of individual trees. A strong correlation was detected between the slope gradient and the proportions of returns with height differences more than 0.3, 0.5 and 0.8 m in the total returns, with coefficient of determination R2 of 0.83, 0.76, and 0.60 (n = 41), respectively. PMID:26016907

  1. Seafloor bathymetry in deep and shallow water marine CSEM responses of Nigerian Niger Delta oil field: Effects and corrections

    NASA Astrophysics Data System (ADS)

    Folorunso, Adetayo Femi; Li, Yuguo

    2015-12-01

    Topography distortions in bathymetrically acquired marine Controlled-Source Electromagnetic (mCSEM) responses are capable of misleading interpretation to the presence or absence of the target if not corrected for. For this reason, the effects and correction of bathymetry distortions on the deep and shallow seafloor mCSEM responses of the Niger Delta Oil province were examined in this paper. Marine CSEM response of the Niger Delta geological structure was modelled by using a 2.5D adaptive finite element forward modelling code. In both the deep water and shallow water cases, the bathymetry distortions in the electric field amplitude and phase were found to get smaller with increasing Tx-Rx offsets and contain short-wavelength components in the amplitude curves which persist at all Tx-Rx offsets. In the deep water, topographic effects on the reservoir signatures are not significant, but as water depth reduces, bathymetric distortions become more significant as a result of the airwave effects, masking the target signatures. The correction technique produces a good agreement between the flat-seafloor reservoir model and its equivalent bathymetric model in deep water at 0.25 Hz, while in shallow water, the corrected response only shows good agreement at shorter offsets but becomes complicated at longer offsets due to airwave effects. Transmission frequency was extended above and below 0.25 Hz in the frequency spectrum and the correction method applied. The bathymetry correction at higher frequency (1.75 Hz) is not effective in removing the topographic effects in either deep or shallow water. At 0.05 Hz for both seafloor scenarios, we obtained the best corrected amplitude profiles, removing completely the distortions from both topographic undulation and airwave effects in the shallow water model. Overall, the work shows that the correction technique is effective in reducing bathymetric effects in deep water at medium frequency and in both deep and shallow waters at a low

  2. Modelling static 3-D spatial background error covariances - the effect of vertical and horizontal transform order

    NASA Astrophysics Data System (ADS)

    Wlasak, M. A.; Cullen, M. J. P.

    2014-06-01

    A major difference in the formulation of the univariate part of static background error covariance models for use in global operational 4DVAR arises from the order in which the horizontal and vertical transforms are applied. This is because the atmosphere is non-separable with large horizontal scales generally tied to large vertical scales and small horizontal scales tied to small vertical scales. Also horizontal length scales increase dramatically as one enters the stratosphere. A study is presented which evaluates the strengths and weaknesses of each approach with the Met Office Unified Model. It is shown that if the vertical transform is applied as a function of horizontal wavenumber then the horizontal globally-averaged variance and the homogenous, isotropic length scale on each model level for each control variable of the training data is preserved by the covariance model. In addition the wind variance and associated length scales are preserved as the scheme preserves the variances and length scales of horizontal derivatives. If the vertical transform is applied in physical space, it is possible to make it a function of latitude at the cost of not preserving the variances and length scales of the horizontal derivatives. Summer and winter global 4DVAR trials have been run with both background error covariance models. A clear benefit is seen in the fit to observations when the vertical transform is in spectral space and is a function of total horizontal wavenumber.

  3. The effects of background pattern and contrast on prey discrimination by the praying mantis Sphodromantis lineola (Burr.).

    PubMed

    Prete, F R

    1992-01-01

    Tethered, adult female Sphodromantis lineola (Burr.) were presented with two groups of two-dimensional stimuli (i.e., 2-D lures) against various backgrounds. Lure Group 1 comprised various black rectangles in three different size arrays: each size array included a 2, 6, or 12 mm square, respectively, several 'worm' lures of a constant width (l2, edge perpendicular to the direction of movement, 3-30 mm), but varying in length (l1, parallel to the direction of movement, 6-114 mm), and several 'antiworm' lures of a constant length but varying width. Group 1 lures were presented against patterned backgrounds of similar luminance: one natural pattern mimicking foliage and the other a random geometric pattern of rectangles. Group 2 lures comprised various configurations and combinations of black and white lures which were presented against white, black, and natural pattern backgrounds. The appetitive behaviors of approaching and striking at a lure were dependent measures indicating that a stimulus was categorized as prey. For Group 1 lures, overall response rates to lures of the same size were enhanced by the natural pattern background rather than the geometric pattern background. Against the natural pattern background, worm lures were stronger releasers of predatory behavior than antiworm lures of the same size. Lure configuration (especially for the smallest array) was masked by the geometric pattern background, although worm versus antiworm discrimination was apparent with the largest size array. For Group 2 lures, lure-to-background contrast, as well as configuration, effected prey recognition. For instance, lures with low lure-to-background contrast ratios were weaker releasers than those with high ratios, and lures that were darker (versus lighter) than the background were stronger releasers. In addition, particular stimulus properties interacted to effect lure strength. For instance, a weak or strong releaser became stronger or weaker, respectively, when a more or

  4. Effects of Demographic Characteristics, Educational Background, and Supporting Factors on ICT Readiness of Technical and Vocational Teachers in Malaysia

    ERIC Educational Resources Information Center

    Alazzam, Abu-Obaideh; Bakar, Ab Rahim; Hamzah, Ramlah; Asimiran, S.

    2012-01-01

    The aim of this study was to examine ICT readiness and the effects of demographic characteristics, educational background, and support factors on the ICT readiness of technical and vocational teachers in Malaysia. The questionnaire was administered to 329 technical and vocational teachers who are teaching engineering subjects in Malaysian…

  5. Effects of Superimposition and Background Fading on the Sight-Word Reading of a Boy with Autism

    ERIC Educational Resources Information Center

    Birkan, Binyamin; McClannahan, Lynn E.; Krantz, Patricia J.

    2007-01-01

    We used a multiple-baseline design across materials to assess the effects of stimulus superimposition and background fading on the sight-word reading skills of a 6-year-old boy with autism. Before the study began, the boy was taught to make verbal responses when shown 15 photographs of physical education activities and equipment. During baseline…

  6. The Effects of Teacher Background, Teacher Preparation, and Support on Attitudes and Expectations of K-12 Urban Music Educators

    ERIC Educational Resources Information Center

    Doyle, Jennifer L.

    2012-01-01

    The purpose of this study was to determine the effects of personal and professional background factors, teacher preparation, and support on urban music teacher disposition. Specifically, the study aimed to examine the status of K-12 urban music education; verify the psychometric appropriateness of the researcher-created survey instrument; analyze…

  7. Investigating the Effects of Background Knowledge on Chinese Word Processing during Text Reading: Evidence from Eye Movements

    ERIC Educational Resources Information Center

    Jian, Yu-Cin; Ko, Hwa-Wei

    2014-01-01

    This study investigates the effects of background knowledge on Chinese word processing during silent reading by monitoring adult readers' eye movements. Both higher knowledge (physics major) and lower knowledge (nonphysics major) graduate students were given physics texts to read. Higher knowledge readers spent less time rereading and had…

  8. The Effect of Language Background and Socio-Economic Status on Screening Procedures for the Early Identification of Learning Problems.

    ERIC Educational Resources Information Center

    Gershman, Janis; Kershaw, Joan

    This follow-up study investigated the accuracy of screening measures used to detect potential learning problems in kindergarten and Grade 1 children by the Toronto Early Identification and Developmental Program (EIDP). The effect of students' language background and socioeconomic status on the predictive validity of the identification procedure…

  9. Limitations of Significance Testing in Clinical Research: A Review of Multiple Comparison Corrections and Effect Size Calculations with Correlated Measures.

    PubMed

    Vasilopoulos, Terrie; Morey, Timothy E; Dhatariya, Ketan; Rice, Mark J

    2016-03-01

    Modern clinical research commonly uses complex designs with multiple related outcomes, including repeated-measures designs. While multiple comparison corrections and effect size calculations are needed to more accurately assess an intervention's significance and impact, understanding the limitations of these methods in the case of dependency and correlation is important. In this review, we outline methods for multiple comparison corrections and effect size calculations and considerations in cases of correlation and summarize relevant simulation studies to illustrate these concepts. PMID:26891394

  10. Evaluating the Effect of a Lecturer's Language Background on a Student Rating of Teaching Form

    ERIC Educational Resources Information Center

    Ogier, John

    2005-01-01

    This study, using student ratings of lecturers, examines the perceived effect of the lecturers ability to communicate effectively. The relationship between the standard question -- "The lecturer was able to communicate ideas and information clearly" -- and the global rating question -- "Overall, the lecturer is an effective teacher" -- was…

  11. Religious Background and Educational Attainment: The Effects of Buddhism, Islam, and Judaism

    ERIC Educational Resources Information Center

    Sander, William

    2010-01-01

    The effects of Buddhism, Islam, and Judaism on educational attainment in the United States are examined. OLS estimates of educational attainment and Probit estimates of college attainment are undertaken. It is shown that Islam and Judaism have similar positive effects on attainment relative to Protestants and Catholics. The effect of Buddhism is…

  12. Correction of apparent finite size effects in the area per lipid of lipid membranes simulations.

    PubMed

    Herce, Henry D; Garcia, Angel E

    2006-12-14

    Molecular dynamics simulations of lipids bilayers have reported that the average area per lipid increases with the size of the simulated unit cell under constant temperature, pressure, and number of molecules. Here we show that the cause of this finite size effect are artifacts associated with the heat bath coupling. This can be corrected by coupling individually each degree of freedom to the heat bath, instead of coupling globally the system. We present the results of the investigation on three aspects of molecular dynamics simulations and their effect on the computed average area per lipid: (I) the accuracy in the computation of electrostatic interactions, the energy, and the virial, (II) long range Lennard-Jones interactions for systems with symmetry in one plane, and (III) thermodynamic baths. We show that the average area per lipid remains constant for simulations of systems containing 32, 64, and 256 lipids. PMID:17176158

  13. Electroweakino pair production at the LHC: NLO SUSY-QCD corrections and parton-shower effects

    NASA Astrophysics Data System (ADS)

    Baglio, Julien; Jäger, Barbara; Kesenheimer, Matthias

    2016-07-01

    We present a set of NLO SUSY-QCD calculations for the pair production of neutralinos and charginos at the LHC, and their matching to parton-shower programs in the framework of the POWHEG-BOX program package. The code we have developed provides a SUSY Les Houches Accord interface for setting supersymmetric input parameters. Decays of the neutralinos and charginos and parton-shower effects can be simulated with PYTHIA. To illustrate the capabilities of our program, we present phenomenological results for a representative SUSY parameter point. We find that NLO-QCD corrections increase the production rates for neutralinos and charginos significantly. The impact of parton-shower effects on distributions of the weakinos is small, but non-negligible for jet distributions.

  14. [Effects of neonatal fluvoxamine administration to white rats and their correction by semax treatment].

    PubMed

    Volodina, M A; Merchieva, S A; Sebentsova, E A; Glazova, N Iu; Manchenko, D M; Andreeva, L A; Levickaia, N G; Kamenskiĭ, A A; Miasoedov, N F

    2014-01-01

    The aim of this work was to study the delayed effects of chronic neonatal administration of the selective serotonin reuptake inhibitor fluvoxamine (FA) to white rat pups and to estimate the possibility to correct these effects by treatment with semax. Fluvoxamine was injected intraperitoneally at a dose of 10 mg/kg from postnatal days 1 to 14, and semax was injected intranasally at a dose of 0.05 mg/kg from postnatal days 15 to 28. It was shown that neonatal FA administration produced a significant delay in animal somatic growth. A loss in body weight was detected both during FA administration and 4-6 weeks after the last injection. Furthermore, FA administration increased the anxiety level and disturbed the learning ability of animals. The negative consequences of neonatal FA administration were largely compensated by Semax. PMID:25735182

  15. Relative Age Effects in Athletic Sprinting and Corrective Adjustments as a Solution for Their Removal

    PubMed Central

    2015-01-01

    Relative Age Effects (RAEs) refer to the selection and performance differentials between children and youth who are categorized in annual-age groups. In the context of Swiss 60m athletic sprinting, 7761 male athletes aged 8 – 15 years were analysed, with this study examining whether: (i) RAE prevalence changed across annual age groups and according to performance level (i.e., all athletes, Top 50%, 25% & 10%); (ii) whether the relationship between relative age and performance could be quantified, and corrective adjustments applied to test if RAEs could be removed. Part one identified that when all athletes were included, typical RAEs were evident, with smaller comparative effect sizes, and progressively reduced with older age groups. However, RAE effect sizes increased linearly according to performance level (i.e., all athletes – Top 10%) regardless of age group. In part two, all athletes born in each quartile, and within each annual age group, were entered into linear regression analyses. Results identified that an almost one year relative age difference resulted in mean expected performance differences of 10.1% at age 8, 8.4% at 9, 6.8% at 10, 6.4% at 11, 6.0% at 12, 6.3% at 13, 6.7% at 14, and 5.3% at 15. Correction adjustments were then calculated according to day, month, quarter, and year, and used to demonstrate that RAEs can be effectively removed from all performance levels, and from Swiss junior sprinting more broadly. Such procedures could hold significant implications for sport participation as well as for performance assessment, evaluation, and selection during athlete development. PMID:25844642

  16. Corrections for the combined effects of decay and dead time in live-timed counting of short-lived radionuclides.

    PubMed

    Fitzgerald, R

    2016-03-01

    Studies and calibrations of short-lived radionuclides, for example (15)O, are of particular interest in nuclear medicine. Yet counting experiments on such species are vulnerable to an error due to the combined effect of decay and dead time. Separate decay corrections and dead-time corrections do not account for this issue. Usually counting data are decay-corrected to the start time of the count period, or else instead of correcting the count rate, the mid-time of the measurement is used as the reference time. Correction factors are derived for both those methods, considering both extending and non-extending dead time. Series approximations are derived here and the accuracy of those approximations are discussed. PMID:26682893

  17. Measuring X-Ray Polarization in the Presence of Systematic Effects: Known Background

    NASA Technical Reports Server (NTRS)

    Elsner, Ronald F.; O'Dell, Stephen L.; Weisskopf, Martin C.

    2012-01-01

    The prospects for accomplishing x-ray polarization measurements of astronomical sources have grown in recent years, after a hiatus of more than 37 years. Unfortunately, accompanying this long hiatus has been some confusion over the statistical uncertainties associated with x-ray polarization measurements of these sources. We have initiated a program to perform the detailed calculations that will offer insights into the uncertainties associated with x-ray polarization measurements. Here we describe a mathematical formalism for determining the 1- and 2-parameter errors in the magnitude and position angle of x-ray (linear) polarization in the presence of a (polarized or unpolarized) background. We further review relevant statistics including clearly distinguishing between the Minimum Detectable Polarization (MDP) and the accuracy of a polarization measurement.

  18. Effects of error correction during assessment probes on the acquisition of sight words for students with moderate intellectual disabilities.

    PubMed

    Waugh, Rebecca E; Alberto, Paul A; Fredrick, Laura D

    2011-01-01

    Simultaneous prompting is an errorless learning strategy designed to reduce the number of errors students make; however, research has shown a disparity in the number of errors students make during instructional versus probe trials. This study directly examined the effects of error correction versus no error correction during probe trials on the effectiveness and efficiency of simultaneous prompting on the acquisition of sight words by three middle school students with moderate intellectual disabilities. A single-case adapted alternating treatments (Sindelar, Rosenberg, & Wilson, 1985) embedded in a multiple baseline across word sets design was employed to examine the effects of error correction during probe trials in order to reduce error rates. A functional relation was established for two of the three students for the use of error correction during probe sessions to reduce error rates. Error correction during assessment probes required fewer sessions to criterion, resulted in fewer probe errors, resulted in a higher percentage of correct responding on the next subsequent trial, and required less total probe time. For two of the three students, probes with error correction resulted in a more rapid acquisition rate requiring fewer sessions to criterion. PMID:20884169

  19. Measuring Neural Entrainment to Beat and Meter in Infants: Effects of Music Background.

    PubMed

    Cirelli, Laura K; Spinelli, Christina; Nozaradan, Sylvie; Trainor, Laurel J

    2016-01-01

    Caregivers often engage in musical interactions with their infants. For example, parents across cultures sing lullabies and playsongs to their infants from birth. Behavioral studies indicate that infants not only extract beat information, but also group these beats into metrical hierarchies by as early as 6 months of age. However, it is not known how this is accomplished in the infant brain. An EEG frequency-tagging approach has been used successfully with adults to measure neural entrainment to auditory rhythms. The current study is the first to use this technique with infants in order to investigate how infants' brains encode rhythms. Furthermore, we examine how infant and parent music background is associated with individual differences in rhythm encoding. In Experiment 1, EEG was recorded while 7-month-old infants listened to an ambiguous rhythmic pattern that could be perceived to be in two different meters. In Experiment 2, EEG was recorded while 15-month-old infants listened to a rhythmic pattern with an unambiguous meter. In both age groups, information about music background (parent music training, infant music classes, hours of music listening) was collected. Both age groups showed clear EEG responses frequency-locked to the rhythms, at frequencies corresponding to both beat and meter. For the younger infants (Experiment 1), the amplitudes at duple meter frequencies were selectively enhanced for infants enrolled in music classes compared to those who had not engaged in such classes. For the older infants (Experiment 2), amplitudes at beat and meter frequencies were larger for infants with musically-trained compared to musically-untrained parents. These results suggest that the frequency-tagging method is sensitive to individual differences in beat and meter processing in infancy and could be used to track developmental changes. PMID:27252619

  20. Measuring Neural Entrainment to Beat and Meter in Infants: Effects of Music Background

    PubMed Central

    Cirelli, Laura K.; Spinelli, Christina; Nozaradan, Sylvie; Trainor, Laurel J.

    2016-01-01

    Caregivers often engage in musical interactions with their infants. For example, parents across cultures sing lullabies and playsongs to their infants from birth. Behavioral studies indicate that infants not only extract beat information, but also group these beats into metrical hierarchies by as early as 6 months of age. However, it is not known how this is accomplished in the infant brain. An EEG frequency-tagging approach has been used successfully with adults to measure neural entrainment to auditory rhythms. The current study is the first to use this technique with infants in order to investigate how infants' brains encode rhythms. Furthermore, we examine how infant and parent music background is associated with individual differences in rhythm encoding. In Experiment 1, EEG was recorded while 7-month-old infants listened to an ambiguous rhythmic pattern that could be perceived to be in two different meters. In Experiment 2, EEG was recorded while 15-month-old infants listened to a rhythmic pattern with an unambiguous meter. In both age groups, information about music background (parent music training, infant music classes, hours of music listening) was collected. Both age groups showed clear EEG responses frequency-locked to the rhythms, at frequencies corresponding to both beat and meter. For the younger infants (Experiment 1), the amplitudes at duple meter frequencies were selectively enhanced for infants enrolled in music classes compared to those who had not engaged in such classes. For the older infants (Experiment 2), amplitudes at beat and meter frequencies were larger for infants with musically-trained compared to musically-untrained parents. These results suggest that the frequency-tagging method is sensitive to individual differences in beat and meter processing in infancy and could be used to track developmental changes. PMID:27252619

  1. Separability of test fields equations on the C -metric background. II. Rotating case and the Meissner effect

    NASA Astrophysics Data System (ADS)

    KofroÅ, David

    2016-05-01

    We present the separation of the Teukolsky master equation for the test field of arbitrary spin on the background of the rotating C -metric. We also summarize and simplify some known results about Debye potentials of these fields on type D background. The equation for the Debye potential is also separated. Solving for the Debye potential of the electromagnetic field we show that on the extremely rotating C -metric no magnetic field can penetrate through the outer black hole horizon—we thus recover the Meissner effect for the C -metric.

  2. Correcting for Incomplete Saturation and Off-Resonance Effects in Multiple-Site Saturation-Transfer Kinetic Measurements

    NASA Astrophysics Data System (ADS)

    Kingsley, Peter B.; Monahan, W. Gordon

    2000-09-01

    The effects of incomplete saturation and off-resonance irradiation on nuclear magnetic resonance saturation-transfer measurements of three-site chemical-exchange rates are discussed. A new method that uses double-saturation measurements is compared with two published methods, one that uses single-saturation measurements and one that uses a single-saturation measurement and a double-saturation measurement. Several formulas are compared for measuring the exchange rate constant kDE for exchange from a detected spin D to an exchanging spin E in the presence of exchange from spin D to a competing spin C. For each method, formulas are derived with corrections for incomplete saturation or off-resonance effects, with both corrections, and with neither correction. Exact formulas are available for three exchanging sites with incomplete saturation if there are no off-resonance effects. Off-resonance corrections are imperfect even with complete saturation.

  3. A compact quantum correction model for symmetric double gate metal-oxide-semiconductor field-effect transistor

    SciTech Connect

    Cho, Edward Namkyu; Shin, Yong Hyeon; Yun, Ilgu

    2014-11-07

    A compact quantum correction model for a symmetric double gate (DG) metal-oxide-semiconductor field-effect transistor (MOSFET) is investigated. The compact quantum correction model is proposed from the concepts of the threshold voltage shift (ΔV{sub TH}{sup QM}) and the gate capacitance (C{sub g}) degradation. First of all, ΔV{sub TH}{sup QM} induced by quantum mechanical (QM) effects is modeled. The C{sub g} degradation is then modeled by introducing the inversion layer centroid. With ΔV{sub TH}{sup QM} and the C{sub g} degradation, the QM effects are implemented in previously reported classical model and a comparison between the proposed quantum correction model and numerical simulation results is presented. Based on the results, the proposed quantum correction model can be applicable to the compact model of DG MOSFET.

  4. Physiological correction of lingual dysfunction with the "Tongue Right Positioner": Beneficial effects on the upper airways.

    PubMed

    Mauclaire, Claude; Vanpoulle, Frédéric; Saint-Georges-Chaumet, Yann

    2015-09-01

    Several studies have demonstrated the beneficial role of functional tongue therapy in stabilizing treatments for dental malocclusion and treating sleep-disordered breathing (SDB). The aim of this retrospective study was to evaluate the effect on the upper airways of the Tongue Right Positioner device (TRP) used for the correction of atypical swallowing. We analyzed lateral headfilms of 94 orthodontic patients aged between 11 and 17, before the start of treatment and after establishment of mature swallowing, treated with the TRP (TRP group) or by reeducation exercises (control group). In the TRP group, the establishment of mature swallowing occurs twice as fast as in the control group. This led to thinning of the floor of the mouth (-8.38%, P<0.001) linked to anteroposterior enlargement of the pharynx (+10.48%, P<0.01), both probably due to an increase in genioglossal and styloglossal muscle tone and correction of cranio-cervical posture (+2.52%, P<0.01). These results are not dependent on the type of orthodontic treatment. They suggest that the TRP could be used in the treatment of SDB. PMID:26282520

  5. Temperature effects and corrections in volume measurements based on liquid-level detection

    SciTech Connect

    Suda, S.; Keisch, B.

    1993-08-01

    Temperature changes affect volume measurements in several ways. The dimensions of the tank, and the density and level of the liquid it contains vary with temperature. In addition, the response signal of the sensor and hence the response of the liquid-level detection device may change with temperature. Level measurement devices can be grouped according to four measurement points of reference: tip of probe, response proportional to the length of probe, top of tank, and liquid surface. This paper describes the physical principles of pressure, capacitance probe, sonic reflections, and visual scales. These are representative of the four types of liquid level detection techniques. Development of the temperature correction algorithm requires that the measurement process be clearly defined, conditions or limitations specified, and that a temperature-effects test be run. Although not difficult or necessarily time-consuming to run, good practice requires a test plan following demonstrated guidelines. Measurement control procedures for remeasurement of the process solution in the tank during normal operation can provide data to validate temperature correction algorithms.

  6. The Complexity in Defining Leadership: How Gifted Students' Backgrounds Influence Their Understanding of Effective Leadership

    ERIC Educational Resources Information Center

    Jackson, Shawon; Sakuma, Satoe; DeVol, Purva

    2015-01-01

    There is no universally accepted definition of what it means to be an effective leader. Individuals understand leadership differently based on their own identities and lived experiences. The purpose of this investigation is to determine how one's ethnicity, class, and gender identities influence their understanding of effective leadership,…

  7. Effective safety measures with tests followed by design correction for aerospace structures

    NASA Astrophysics Data System (ADS)

    Matsumura, Taiki

    Analytical and computational prediction tools enable us to design aircraft and spacecraft components with high degree of confidence. While the accuracy of such predictions has been improved over the years, uncertainty continues to be added by new materials and new technology introduced in order to improve performance. This requires us to have reality checks, such as tests, in order to make sure that the prediction tools are reliable enough to ensure safety. While tests can reveal unsafe designs and lead to design correction, these tests are very costly. Therefore, it is important to manage such a design-test-correction cycle effectively. In this dissertation, we consider three important test stages in the lifecycle of an aviation system. First, we dealt with characterization tests that reveal failure modes of new materials or new geometrical arrangements. We investigated the challenge associated with getting the best characterization with a limited number of tests. We have found that replicating tests to attenuate the effect of noise in observation is not necessary because some surrogate models can serve as a noise filter without having replicated data. Instead, we should focus on exploring the design space with different structural configurations in order to discover unknown failure modes. Next, we examined post-design tests for design acceptance followed by possible redesign. We looked at the question of how to balance the desire for better performance achieved by redesign against the cost of redesign. We proposed a design optimization framework that provides tradeoff information between the expected performance improvement by redesign and the probability of redesign, equivalent to the cost of redesign. We also demonstrated that the proposed method can reduce the performance loss due to a conservative reliability estimate. The ultimate test, finally, is whether the structures do not fail in flight. Once an accident occurs, an accident investigation takes place

  8. Effects of the background electrolyte on Th(IV) sorption to muscovite mica

    NASA Astrophysics Data System (ADS)

    Schmidt, Moritz; Hellebrandt, Stefan; Knope, Karah E.; Lee, Sang Soo; Stubbs, Joanne E.; Eng, Peter J.; Soderholm, L.; Fenter, Paul

    2015-09-01

    The adsorption of tetravalent thorium on the muscovite mica (0 0 1) basal plane was studied by X-ray crystal truncation rod (CTR) and resonant anomalous X-ray reflectivity (RAXR) measurements and alpha spectrometry in the presence of perchlorate background electrolytes LiClO4, NaClO4, and KClO4 ([Th(IV)] = 0.1 mM, I = 0.1 M or 0.01 M, pH = 3.3 ± 0.3). RAXR data directly reveal a strong influence of the background electrolyte on the actinide sorption. No significant Th adsorption was observed in 0.1 M NaClO4, i.e., the Th coverage θ(Th), the number of Th per unit cell area of the muscovite surface (AUC = 46.72 Å2), was ⩽0.01 Th/AUC, whereas limited uptake (θ(Th) ∼ 0.04 Th/AUC) was detected at a lower ionic strength (I = 0.01 M). These results are in stark contrast to the behavior of Th in 0.1 M NaCl which showed a coverage of 0.4 Th/AUC (Schmidt et al., 2012a). Th uptake was also influenced by the electrolyte cation. Weak adsorption was observed in 0.1 M KClO4 (θ(Th) ∼ 0.07 Th/AUC) similar to the results in NaClO4 at lower ionic strength. In contrast, strong adsorption was found in 0.1 M LiClO4, with θ(Th) = 4.9 Th/AUC, a ∼10-fold increase compared with that previously reported in NaCl. These differences are confirmed independently by ex situ alpha spectrometry, which shows no measurable Th coverage in 0.1 M NaClO4 background in contrast to a large coverage of 1.6 Th/AUC in 0.1 M LiClO4. Alpha spectrometry cannot be obtained in situ, but sample preparation requires several washing steps that may affect Th(IV) sorption, RAXR, however, is considered to reflect the in situ sorption structure. The CTR/RAXR analyses of Th-LiClO4 show the sorption structure consisting of Th species that are broadly distributed, centered at heights of 4.1 Å and 29 Å distance from the interface. Neither the very large distribution height of the second species nor the high coverage can be explained with (hydrated) ionic adsorption, suggesting that the enhanced uptake is

  9. A field investigation on the effects of background erosion on the free span development of a submarine pipeline

    NASA Astrophysics Data System (ADS)

    Wen, Shipeng; Xu, Jishang; Hu, Guanghai; Dong, Ping; Shen, Hong

    2015-08-01

    The safety of submarine pipelines is largely influenced by free spans and corrosions. Previous studies on free spans caused by seabed scours are mainly based on the stable environment, where the background seabed scour is in equilibrium and the soil is homogeneous. To study the effects of background erosion on the free span development of subsea pipelines, a submarine pipeline located at the abandoned Yellow River subaqueous delta lobe was investigated with an integrated surveying system which included a Multibeam bathymetric system, a dual-frequency side-scan sonar, a high resolution sub-bottom profiler, and a Magnetic Flux Leakage (MFL) sensor. We found that seabed homogeneity has a great influence on the free span development of the pipeline. More specifically, for homogeneous background scours, the morphology of scour hole below the pipeline is quite similar to that without the background scour, whereas for inhomogeneous background scour, the nature of spanning is mainly dependent on the evolution of seabed morphology near the pipeline. Magnetic Flux Leakage (MFL) detection results also reveal the possible connection between long free spans and accelerated corrosion of the pipeline.

  10. Biotransformation and adsorption of pharmaceutical and personal care products by activated sludge after correcting matrix effects.

    PubMed

    Deng, Yu; Li, Bing; Yu, Ke; Zhang, Tong

    2016-02-15

    This study reported significant suppressive matrix effects in analyses of six pharmaceutical and personal care products (PPCPs) in activated sludge, sterilized activated sludge and untreated sewage by ultra-performance liquid chromatography-tandem mass spectrometry. Quantitative matrix evaluation on selected PPCPs supplemented the limited quantification data of matrix effects on mass spectrometric determination of PPCPs in complex environment samples. The observed matrix effects were chemical-specific and matrix-dependent, with the most pronounced average effect (-55%) was found on sulfadiazine in sterilized activated sludge. After correcting the matrix effects by post-spiking known amount of PPCPs, the removal mechanisms and biotransformation kinetics of selected PPCPs in activated sludge system were revealed by batch experiment. Experimental data elucidated that the removal of target PPCPs in the activated sludge process was mainly by biotransformation while contributions of adsorption, hydrolysis and volatilization could be neglected. High biotransformation efficiency (52%) was observed on diclofenac while other three compounds (sulfadiazine, sulfamethoxazole and roxithromycin) were partially biotransformed by ~40%. The other two compounds, trimethoprim and carbamazepine, showed recalcitrant to biotransformation of the activated sludge. PMID:26706769

  11. The effect of background music on the perception of personality and demographics.

    PubMed

    Lastinger, Daniel L

    2011-01-01

    This study seeks to discover stereotypes people may have about different music genres and if these stereotypes are projected onto an individual. Also, the study investigates if music therapy students are more or less biased than non-music majors in this regard. Subjects (N=388) were comprised of student members of the American Music Therapy Association (N=182) and students from a college in the southeastern United States who were not music majors (N=206). Subjects were asked to listen to a recording and complete a short survey. Subjects assigned to the control condition heard only a person reading a script. Subjects assigned to one of the four experimental conditions heard the same recording mixed with background music and ambient crowd noise, intended to simulate a live performance. Subjects were asked to rate the person in the recording on personality descriptors and predict demographic information in the survey. Many of the survey responses were significantly affected by the genre of music. For example, it was shown that when in the presence of rap or country music, all subjects rated the personality of the person in the recording significantly more negative than when in the presence of classical, jazz, or no music. There were no significant differences between the groups for any variable or condition when comparing survey responses between college students and AMTA student members. PMID:21938892

  12. Effects of Vendor and Genetic Background on the Composition of the Fecal Microbiota of Inbred Mice

    PubMed Central

    Ericsson, Aaron C.; Davis, J. Wade; Spollen, William; Bivens, Nathan; Givan, Scott; Hagan, Catherine E.; McIntosh, Mark; Franklin, Craig L.

    2015-01-01

    The commensal gut microbiota has been implicated as a determinant in several human diseases and conditions. There is mounting evidence that the gut microbiota of laboratory mice (Mus musculus) similarly modulates the phenotype of mouse models used to study human disease and development. While differing model phenotypes have been reported using mice purchased from different vendors, the composition and uniformity of the fecal microbiota in mice of various genetic backgrounds from different vendors is unclear. Using culture-independent methods and robust statistical analysis, we demonstrate significant differences in the richness and diversity of fecal microbial populations in mice purchased from two large commercial vendors. Moreover, the abundance of many operational taxonomic units, often identified to the species level, as well as several higher taxa, differed in vendor- and strain-dependent manners. Such differences were evident in the fecal microbiota of weanling mice and persisted throughout the study, to twenty-four weeks of age. These data provide the first in-depth analysis of the developmental trajectory of the fecal microbiota in mice from different vendors, and a starting point from which researchers may be able to refine animal models affected by differences in the gut microbiota and thus possibly reduce the number of animals required to perform studies with sufficient statistical power. PMID:25675094

  13. Uniformity of cosmic microwave background as a non-inflationary geometrical effect

    NASA Astrophysics Data System (ADS)

    Vlahovic, Branislav; Eingorn, Maxim; Ilie, Cosmin

    2015-10-01

    The conventional ΛCDM cosmological model supplemented by the inflation concept describes the Universe very well. However, there are still a few concerns: new Planck data impose constraints on the shape of the inflaton potential, which exclude a lot of inflationary models; dark matter is not detected directly, and dark energy is not understood theoretically on a satisfactory level. In this brief sketch, we investigate an alternative cosmological model with spherical spatial geometry and an additional perfect fluid with the constant parameter ω = -1/3 in the linear equation of state. It is demonstrated explicitly that in the framework of such a model it is possible to satisfy the supernovae data at the same level of accuracy as within the ΛCDM model and at the same time suppose that the observed cosmic microwave background (CMB) radiation originates from a very limited space region. This is ensured by introducing an additional condition of light propagation between the antipodal points during the age of the Universe. Consequently, the CMB uniformity can be explained without the inflation scenario. The corresponding drawbacks of the model with respect to its comparison with the CMB data are also discussed.

  14. Novel effects of chain flexibility, external force, and background stochasticity on polymer translocation

    NASA Astrophysics Data System (ADS)

    Sung, Wokyung

    2011-03-01

    The polymer translocation through membranes and the polymer crossing over activation barriers in general, are ubiquitous in cell biology and biotechnological applications. Because they are interconnected flexible systems, polymers in translocation incur entropic barriers but can thermally surmount them with unusual sensitivity to background biases. In the presence of non-equilibrium noises characteristic of living environments, the translocation can speed up much when resonant activation occurs. As a related issue, I will also discuss the problem of polymer surmounting a potential barrier, where the chain flexibility enhances the crossing. Furthermore, when the chain flexibility leads to conformational changes, the crossing rate can be even more dramatically increased. This conformational flexibility and variability enhance the stochastic resonance, where the chain crossing dynamics at an optimal temperature and chain length is maximally coherent and resonant to a minute periodic force. Utilizing the self-organizing behaviors mentioned above, we may learn about bio-molecular machinery of living as well as clever means of manipulating it. Korea Research Foundation.

  15. Effects of vendor and genetic background on the composition of the fecal microbiota of inbred mice.

    PubMed

    Ericsson, Aaron C; Davis, J Wade; Spollen, William; Bivens, Nathan; Givan, Scott; Hagan, Catherine E; McIntosh, Mark; Franklin, Craig L

    2015-01-01

    The commensal gut microbiota has been implicated as a determinant in several human diseases and conditions. There is mounting evidence that the gut microbiota of laboratory mice (Mus musculus) similarly modulates the phenotype of mouse models used to study human disease and development. While differing model phenotypes have been reported using mice purchased from different vendors, the composition and uniformity of the fecal microbiota in mice of various genetic backgrounds from different vendors is unclear. Using culture-independent methods and robust statistical analysis, we demonstrate significant differences in the richness and diversity of fecal microbial populations in mice purchased from two large commercial vendors. Moreover, the abundance of many operational taxonomic units, often identified to the species level, as well as several higher taxa, differed in vendor- and strain-dependent manners. Such differences were evident in the fecal microbiota of weanling mice and persisted throughout the study, to twenty-four weeks of age. These data provide the first in-depth analysis of the developmental trajectory of the fecal microbiota in mice from different vendors, and a starting point from which researchers may be able to refine animal models affected by differences in the gut microbiota and thus possibly reduce the number of animals required to perform studies with sufficient statistical power. PMID:25675094

  16. Norm stability in Jirisan National Park: effects of time, existing conditions, and background characteristics.

    PubMed

    Kim, Sang-Oh; Shelby, Bo

    2008-04-01

    Norm stability is an important issue to consider in using the normative approach as a component of resource management decision making. This study examines three major questions related to norm stability: (1) Do norms change over time? (2) Do existing conditions affect norms? (3) Do background characteristics and visitation patterns affect norms? Data used in this study were collected at a campground in the Jirisan National Park (JNP) of Korea in 1993, 1994, and 2003. A total of 396 subjects were used for the study (120 for 1993, 106 for 1994, and 170 for 2003). Changes in the standards for "quiet time" and "seeing others littering" were statistically significant, but there was no change in the standard for "number of other tents." There was little change in norm agreement or norm prevalence. Existing conditions were strongly correlated with standards for number of other tents but results were mixed for the other two indicators. Users' demographic characteristics and visitation patterns were not generally related to norms. Findings of the study are discussed. PMID:18214588

  17. Background sources at PEP

    SciTech Connect

    Lynch, H.; Schwitters, R.F.; Toner, W.T.

    1988-01-01

    Important sources of background for PEP experiments are studied. Background particles originate from high-energy electrons and positrons which have been lost from stable orbits, ..gamma..-rays emitted by the primary beams through bremsstrahlung in the residual gas, and synchrotron radiation x-rays. The effect of these processes on the beam lifetime are calculated and estimates of background rates at the interaction region are given. Recommendations for the PEP design, aimed at minimizing background are presented. 7 figs., 4 tabs.

  18. Sorting chromatic sextupoles for easily and effectively correcting second order chromaticity in the Relativistic Heavy Ion Collider

    SciTech Connect

    Luo,Y.; Tepikian, S.; Fischer, W.; Robert-Demolaize, G.; Trbojevic, D.

    2009-01-02

    Based on the contributions of the chromatic sextupole families to the half-integer resonance driving terms, we discuss how to sort the chromatic sextupoles in the arcs of the Relativistic Heavy Ion Collider (RHIC) to easily and effectively correct the second order chromaticities. We propose a method with 4 knobs corresponding to 4 pairs of chromatic sextupole families to online correct the second order chromaticities. Numerical simulation justifies this method, showing that this method reduces the unbalance in the correction strengths of sextupole families and avoids the reversal of sextupole polarities. Therefore, this method yields larger dynamic apertures for the proposed RHIC 2009 100GeV polarized proton run lattices.

  19. Method and apparatus for correcting eddy current signal voltage for temperature effects

    DOEpatents

    Kustra, Thomas A.; Caffarel, Alfred J.

    1990-01-01

    An apparatus and method for measuring physical characteristics of an electrically conductive material by the use of eddy-current techniques and compensating measurement errors caused by changes in temperature includes a switching arrangement connected between primary and reference coils of an eddy-current probe which allows the probe to be selectively connected between an eddy current output oscilloscope and a digital ohm-meter for measuring the resistances of the primary and reference coils substantially at the time of eddy current measurement. In this way, changes in resistance due to temperature effects can be completely taken into account in determining the true error in the eddy current measurement. The true error can consequently be converted into an equivalent eddy current measurement correction.

  20. Effect of photometric detector spectral response quality on white LED spectral mismatch correction factors.

    PubMed

    Rosas, E; Estrada-Hernández, A

    2016-07-01

    Light-emitting-diode (LED)-based solid-state lighting has become a real option for private and public lighting after achieving high total luminous flux (TLF) and luminous efficacy levels, thus promoting the development of energy efficient use regulation to be fulfilled by LED lamps and LED luminaires. Here, we propose a photometer-quality-based fast-checking criterion. This allows photometric technicians to perform a quick evaluation of the photometric head spectral response quality effect on the LED source spectral mismatch correction factor-when determining the TLF and luminous efficacy minimum approved levels-performance parameters subject to mandatory verification by the conformity assessment procedures technically supporting the corresponding regulation. The proposed criterion applies for a wide range of photometric detector heads' qualities (2.6%≤f1'≤36.4%). PMID:27409220

  1. Effective-range corrections to three-body recombination for atoms with large scattering length

    SciTech Connect

    Hammer, H.-W.; Laehde, Timo A.; Platter, L.

    2007-03-15

    Few-body systems with large scattering length a have universal properties that do not depend on the details of their interactions at short distances. The rate constant for three-body recombination of bosonic atoms of mass m into a shallow dimer scales as ({Dirac_h}/2{pi})a{sup 4}/m times a log-periodic function of the scattering length. We calculate the leading and subleading corrections to the rate constant, which are due to the effective range of the atoms, and study the correlation between the rate constant and the atom-dimer scattering length. Our results are applied to {sup 4}He atoms as a test case.

  2. Effect of higher harmonic corrections on the detection of massive black hole binaries with LISA

    NASA Astrophysics Data System (ADS)

    Porter, Edward K.; Cornish, Neil J.

    2008-09-01

    Massive black hole binaries are key targets for the space based gravitational wave Laser Interferometer Space Antenna (LISA). Several studies have investigated how LISA observations could be used to constrain the parameters of these systems. Until recently, most of these studies have ignored the higher harmonic corrections to the waveforms. Here we analyze the effects of the higher harmonics in more detail by performing extensive Monte Carlo simulations. We pay particular attention to how the higher harmonics impact parameter correlations, and show that the additional harmonics help mitigate the impact of having two laser links fail, by allowing for an instantaneous measurement of the gravitational wave polarization with a single interferometer channel. By looking at parameter correlations we are able to explain why certain mass ratios provide dramatic improvements in certain parameter estimations, and illustrate how the improved polarization measurement improves the prospects for single interferometer operation.

  3. Effect of an enrichment program on DAT scores of potential dental students from disadvantaged backgrounds.

    PubMed

    Johnson, Kimberly P; Woolfolk, Marilyn; May, Kenneth B; Inglehart, Marita R

    2013-08-01

    The objectives of this study were to explore whether Dental Admission Test (DAT) training in an enrichment program for potential dental students increases the participants' Perceptual Achievement Test (PAT) and academic average (AA) scores and whether the length of the program and personal factors such as the number of disadvantages correlate with the DAT scores. Data were collected from 361 students in the summer enrichment program at one dental school between 1994 and 2011. Their baseline, midpoint, and end of program PAT and AA DAT scores were collected. Seventy students self-reported official scores. These students' PAT scores increased from 14.40 at baseline to 17.09 at midpoint to 17.84 at program end (p<0.001), and their AA scores increased from 13.53 to 14.09 to 15.12 (p<0.001). Their official scores were higher than the beginning scores (PAT: 14.42 vs. 16.15; p<0.001; AA: 13.61 vs. 16.23; p<0.001). The longer the program, the more the students improved their official scores (PAT: r=0.35; p=0.003; AA: r=0.24; p=0.044). The more disadvantages the students self-reported, the better their official test scores were (PAT: r=0.40; p<0.001; AA: r=0.43; p<0.001). This study found that the DAT training during summer enrichment programs for students from disadvantaged backgrounds led to significant improvements in their DAT scores. The longer the programs, the more the students improved; and the more disadvantages the students had, the more they benefitted. PMID:23929576

  4. Modeling cognitive effects on visual search for targets in cluttered backgrounds

    NASA Astrophysics Data System (ADS)

    Snorrason, Magnus; Ruda, Harald; Hoffman, James

    1998-07-01

    To understand how a human operator performs visual search in complex scenes, it is necessary to take into account top- down cognitive biases in addition to bottom-up visual saliency effects. We constructed a model to elucidate the relationship between saliency and cognitive effects in the domain of visual search for distant targets in photo- realistic images of cluttered scenes. In this domain, detecting targets is difficult and requires high visual acuity. Sufficient acuity is only available near the fixation point, i.e. in the fovea. Hence, the choice of fixation points is the most important determinant of whether targets get detected. We developed a model that predicts the 2D distribution of fixation probabilities directly from an image. Fixation probabilities were computed as a function of local contrast (saliency effect) and proximity to the horizon (cognitive effect: distant targets are more likely to be found c close to the horizon). For validation, the model's predictions were compared to ensemble statistics of subjects' actual fixation locations, collected with an eye- tracker. The model's predictions correlated well with the observed data. Disabling the horizon-proximity functionality of the model significantly degraded prediction accuracy, demonstrating that cognitive effects must be accounted for when modeling visual search.

  5. Effects of adopting new precession, nutation and equinox corrections on the terrestrial reference frame

    NASA Technical Reports Server (NTRS)

    Zhu, S. Y.; Mueller, I. I.

    1982-01-01

    The effects of adopting new definitive precession and equinox corrections on the terrestrial reference frame was investigated. It is noted that: (1) the effect on polar motion is a diurnal periodic term with an amplitude increasing linearly in time whole on UT1 it is a linear term; (2) general principles are given to determine the effects of small rotations of the frame of a conventional inertial reference system (CIS) on the frame of the conventional terrestrial reference system (CTS); (3) seven CTS options are presented, one of which is necessary to accommodate such rotation. Accommodating possible future changes in the astronomical nutation is discussed. The effects of differences which may exist between the various CTS's and CIS's on Earth rotation parameters (ERP) and how these differences can be determined are examined. It is shown that the CTS differences can be determined from observations made at the same site, while the CIS differences by comparing the ERP's determined by the different techniques during the same time period.

  6. Using water raman intensity to determine the effective excitation and emission path lengths of fluorophotometers for correcting fluorescence inner filter effect

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Fluorescence and Raman inner filter effects (IFE) cause spectral distortion and nonlinearity between spectral signal intensity with increasing analyte concentration. Convenient and effective correction of fluorescence IFE has been an active research goal for decades. Presented herein is the finding ...

  7. Attracting, Developing and Retaining Effective Teachers: Background Report for the United States

    ERIC Educational Resources Information Center

    Walsh, Kate; Wilcox, Danielle; Palmaffy, Tyce; Tracy, Christopher; Yiamouyiannis, Zeus; Ostermeier, Amy; Garcia, Lenore Yaffee

    2004-01-01

    This report presents a balanced picture of the debate on teacher quality in the U.S. and focuses on the aspects of teacher policy dealing with attracting, recruiting, developing and retaining effective teachers by synthesizing relevant research, identifying innovative and successful policy practices, facilitating exchanges of lessons among…

  8. Effective University Teaching: Views of Australian University Students from Low Socio-Economic Status Backgrounds

    ERIC Educational Resources Information Center

    Devlin, Marcia; O'Shea, Helen

    2012-01-01

    As the Australian higher education population further diversifies as a result of federal government policy changes, the collective understanding of effective university teaching in the Australian context will need to evolve to incorporate such shifts. The Australian Government has set clear targets for increased university participation of people…

  9. The Effects of Background Music on Primary School Pupils' Task Performance.

    ERIC Educational Resources Information Center

    Hallam, Susan; Price, John; Katsarou, Georgia

    2002-01-01

    Presents two studies that explored the effects of music perceived as calming and relaxing on arithmetic and memory performance tasks of 10- to 12-year-old children. Reports that the calming music led to better performance on both tasks when compared with the non-music condition. Includes references. (CMK)

  10. Designing Online Courses that Effectively Engage Learners from Diverse Cultural Backgrounds

    ERIC Educational Resources Information Center

    Wang, Minjuan

    2007-01-01

    This study examines the effect of an important cultural dimension--power distance index (PDI)--on learners' perceptions of their online learning experiences. PDI refers to the degree to which a learner's response to another individual in a learning setting is inhibited or otherwise negatively altered when the other individual holds a position that…

  11. Local redistribution of blood under the effect of fixation stress against a background of hypokinesia

    NASA Technical Reports Server (NTRS)

    Kovalev, O. A.; Lysak, V. F.; Severovostokova, V. I.; Shermetevskaya, S. K.

    1980-01-01

    Fixation stress was used as a model of emotional disturbance. The effect of previous restrictions on mobility on the local redistribution of blood resulting from fixation stress was examined. Disturbances in carbohydrate which result from prolonged hypokinesia was studied. Radioactivity was used to determine the local redistribution of blood. Modified factor analysis was used to study the results of the experiment.

  12. Perception of Mandarin Tones: The Effect of L1 Background and Training

    ERIC Educational Resources Information Center

    Wang, Xinchun

    2013-01-01

    This study investigates whether native Hmong speakers' first language (L1) lexical tone experience facilitates or interferes with their perception of Mandarin tones and whether training is effective for perceptual learning of second (L2) tones. In Experiment 1, 3 groups of beginning level learners of Mandarin with different L1 prosodic background…

  13. Decomposing Inequalities in Performance Scores: The Role of Student Background, Peer Effects and School Characteristics

    ERIC Educational Resources Information Center

    Mostafa, Tarek

    2010-01-01

    This paper analyses the mechanisms of stratification and inequalities in educational achievements. The main objective is to determine how stratification leads to unequal educational outcomes and how inequalities are channelled through student characteristics, school characteristics and peer effects. This analysis is undertaken in five countries…

  14. Bilingual Effects on Cognitive and Linguistic Development: Role of Language, Cultural Background, and Education

    ERIC Educational Resources Information Center

    Barac, Raluca; Bialystok, Ellen

    2012-01-01

    A total of 104 six-year-old children belonging to 4 groups (English monolinguals, Chinese-English bilinguals, French-English bilinguals, Spanish-English bilinguals) were compared on 3 verbal tasks and 1 nonverbal executive control task to examine the generality of the bilingual effects on development. Bilingual groups differed in degree of…

  15. Test Anxiety and GCSE Performance: The Effect of Gender and Socio-Economic Background

    ERIC Educational Resources Information Center

    Putwain, David William

    2008-01-01

    Despite a well established body of international literature describing the effect of test anxiety on student performance in a range of assessments, there has been little work conducted on samples of students from the UK. The purpose of this exploratory study is two-fold. First, to establish the relationship between test anxiety and assessment…

  16. Effective Strategies for Teaching Taiwanese Minority Students with Low Achievement and Low Socio-Economic Backgrounds

    ERIC Educational Resources Information Center

    Yen, Shu-Huei

    2009-01-01

    Research shows that minority students continue to fail in the Taiwan public school system. That failure has sharply focused on the urgent need for teachers with the skills to work effectively with minority students. The purpose of this study is to investigate the experiences of an exemplary Taiwanese teacher who teach Indigenous students and to…

  17. Dependence of the effect of aerosols on cirrus clouds on background vertical velocity

    NASA Astrophysics Data System (ADS)

    Lee, Seoung Soo

    2012-07-01

    Cirrus clouds cover approximately 20-25% of the globe and thus play an important role in the Earth's radiation budget. This important role in the radiation budget played by cirrus clouds indicates that aerosol effects on cirrus clouds can have a substantial impact on the variation of global radiative forcing if the ice-water path (IWP) changes. This study examines the aerosol indirect effect (AIE) through changes in the IWP for cirrus cloud cases. This study also examines the dependence of aerosol-cloud interactions in cirrus clouds on the large-scale vertical motion. We use a cloud-system resolving model (CSRM) coupled with a double-moment representation of cloud microphysics. Intensified interactions among the cloud ice number concentration (CINC), deposition and dynamics play a critical role in the IWP increases due to aerosol increases from the preindustrial (PI) level to the present-day (PD) level with a low large-scale vertical velocity. Increased aerosols lead to an increased CINC, providing an increased surface area for water vapor deposition. The increased surface area leads to increased deposition despite decreased supersaturation with increasing aerosols. The increased deposition causes an increased depositional heating which produces stronger updrafts, and these stronger updrafts lead to the increased IWP. However, with a high large-scale vertical velocity, the effect of increased CINC on deposition was not able to offset the effect of decreasing supersaturation with increasing aerosols. The effect of decreasing supersaturation on deposition dominant over that of increasing CINC leads to smaller deposition and IWP at high aerosol with the PD aerosol than at low aerosol with the PI aerosol. The conversion of ice crystals to aggregates through autoconversion and accretion plays a negligible role in the IWP responses to aerosols, as does the sedimentation of aggregates. The sedimentation of ice crystals plays a more important role in the IWP response to

  18. A Cohort Study on Long-Term Adverse Effects of Parental Drinking: Background and Study Design

    PubMed Central

    Lund, Ingunn Olea; Bukten, Anne; Storvoll, Elisabet E; Moan, Inger Synnøve; Skurtveit, Svetlana; Handal, Marte; Nordfjærn, Trond; Brunborg, Geir Scott; Rossow, Ingeborg

    2015-01-01

    Although many studies have addressed adverse outcomes in children of parents with alcohol abuse/dependence, less is known about the possible long-term effects of more normative patterns of parental alcohol consumption, including drinking at lower risk levels and heavy episodic or binge drinking. The extent of harm from parental drinking may therefore be underestimated. With this research proposal, we describe a project that aims to assess possible long-term adverse effects of parental drinking by combining survey and nationwide registry data. Advantages of a longitudinal general population cohort design include that it allows for detailed information on parental drinking through survey data and identification of possible negative long-term health and social outcomes from exposure to parental drinking 1–19 years after exposure through continuously updated nationwide registers. The rich information available from combining survey and registry data allows us to take into account important confounders, mediators, and moderators. PMID:26688663

  19. The effect of background galaxy contamination on the absolute magnitude and light curve speed class of type Ia supernovae

    NASA Technical Reports Server (NTRS)

    Boisseau, John R.; Wheeler, J. Craig

    1991-01-01

    Observational data are presented in support of the hypothesis that background galaxy contamination is present in the photometric data of Ia supernovae and that this effect can account for the observed dispersion in the light curve speeds of most of Ia supernovae. The implication is that the observed dispersion in beta is artificial and that most of Ia supernovae have nearly homogeneous light curves. The result supports the notion that Ia supernovae are good standard candles.

  20. A modified damped Richardson-Lucy algorithm to reduce isotropic background effects in spherical deconvolution.

    PubMed

    Dell'acqua, Flavio; Scifo, Paola; Rizzo, Giovanna; Catani, Marco; Simmons, Andrew; Scotti, Giuseppe; Fazio, Ferruccio

    2010-01-15

    Spherical deconvolution methods have been applied to diffusion MRI to improve diffusion tensor tractography results in brain regions with multiple fibre crossing. Recent developments, such as the introduction of non-negative constraints on the solution, allow a more accurate estimation of fibre orientations by reducing instability effects due to noise robustness. Standard convolution methods do not, however, adequately model the effects of partial volume from isotropic tissue, such as gray matter, or cerebrospinal fluid, which may degrade spherical deconvolution results. Here we use a newly developed spherical deconvolution algorithm based on an adaptive regularization (damped version of the Richardson-Lucy algorithm) to reduce isotropic partial volume effects. Results from both simulated and in vivo datasets show that, compared to a standard non-negative constrained algorithm, the damped Richardson-Lucy algorithm reduces spurious fibre orientations and preserves angular resolution of the main fibre orientations. These findings suggest that, in some brain regions, non-negative constraints alone may not be sufficient to reduce spurious fibre orientations. Considering both the speed of processing and the scan time required, this new method has the potential for better characterizing white matter anatomy and the integrity of pathological tissue. PMID:19781650

  1. Assessment and correction of turbidity effects on Raman observations of chemicals in aqueous solutions.

    PubMed

    Sinfield, Joseph V; Monwuba, Chike K

    2014-01-01

    Improvements in diode laser, fiber optic, and data acquisition technologies are enabling increased use of Raman spectroscopic techniques for both in lab and in situ water analysis. Aqueous media encountered in the natural environment often contain suspended solids that can interfere with spectroscopic measurements, yet removal of these solids, for example, via filtration, can have even greater adverse effects on the extent to which subsequent measurements are representative of actual field conditions. In this context, this study focuses on evaluation of turbidity effects on Raman spectroscopic measurements of two common environmental pollutants in aqueous solution: ammonium nitrate and trichloroethylene. The former is typically encountered in the runoff from agricultural operations and is a strong scatterer that has no significant influence on the Raman spectrum of water. The latter is a commonly encountered pollutant at contaminated sites associated with degreasing and cleaning operations and is a weak scatterer that has a significant influence on the Raman spectrum of water. Raman observations of each compound in aqueous solutions of varying turbidity created by doping samples with silica flour with grain sizes ranging from 1.6 to 5.0 μm were employed to develop relationships between observed Raman signal strength and turbidity level. Shared characteristics of these relationships were then employed to define generalized correction methods for the effect of turbidity on Raman observations of compounds in aqueous solution. PMID:25357083

  2. Von Bertalanffy's dynamics under a polynomial correction: Allee effect and big bang bifurcation

    NASA Astrophysics Data System (ADS)

    Leonel Rocha, J.; Taha, A. K.; Fournier-Prunaret, D.

    2016-02-01

    In this work we consider new one-dimensional populational discrete dynamical systems in which the growth of the population is described by a family of von Bertalanffy's functions, as a dynamical approach to von Bertalanffy's growth equation. The purpose of introducing Allee effect in those models is satisfied under a correction factor of polynomial type. We study classes of von Bertalanffy's functions with different types of Allee effect: strong and weak Allee's functions. Dependent on the variation of four parameters, von Bertalanffy's functions also includes another class of important functions: functions with no Allee effect. The complex bifurcation structures of these von Bertalanffy's functions is investigated in detail. We verified that this family of functions has particular bifurcation structures: the big bang bifurcation of the so-called “box-within-a-box” type. The big bang bifurcation is associated to the asymptotic weight or carrying capacity. This work is a contribution to the study of the big bang bifurcation analysis for continuous maps and their relationship with explosion birth and extinction phenomena.

  3. Evaluation of the Effect of Attenuation Correction by External CT in a Semiconductor SPECT.

    PubMed

    Uchibe, Taku; Miyai, Masahiro; Yata, Nobuhiro; Haramoto, Masuo; Yamamoto, Yasushi; Nakamura, Megumi; Kitagaki, Hajime; Takahashi, Yasuyuki

    2016-07-01

    The discovery of NM530c with a cadmium-zinc-telluride detector (CdZnTe-SPECT) is superior to the conventional Anger-type SPECT with a sodium-iodide detector (NaI-SPECT) in terms of sensitivity and spatial resolution. However, in the clinical example, even in CdZnTe-SPECT, a count decrease in myocardium due to the attenuation of the gamma ray is an issue. This study was conducted to evaluate the effect of computed tomography attenuation correction (CTAC) in CdZnTe-SPECT with the help of external CT. We evaluated the revision effect of uniformity, influence by the difference in attenuation distance, contrast ratio, an uptake rate using the heart phantom. As a result of the phantom studies, a good revision effect was obtained. In the clinical study, there was a statistical significant difference between the contrast ratio before and after CTAC in the inferior wall. In addition, the contrast ratio before and after CTAC in CdZnTe-SPECT image was equal to those of NaI-SPECT image. It was suggested that CTAC using external CT in CdZnTe-SPECT was clinically useful for inferior wall. PMID:27440705

  4. Evaluating Effectively Maintained Inequality: School and post-school transitions, socioeconomic background, academic ability and curricular placement.

    PubMed

    Marks, Gary N

    2013-11-01

    Effectively Maintained Inequality (EMI) is proposed as an explanation for contemporary socioeconomic inequalities in education. Socioeconomic inequalities are 'maintained' by students from lower socioeconomic backgrounds taking less advantageous curricula influencing their post-school destinations. The purpose of this study is to evaluate EMI by addressing several hypotheses derived from the EMI thesis using Australian longitudinal data. It analyses within-school transitions and the transition from school to post-school destinations (elite university, other university, vocational and no post-school study or training). The study also models curricular placement (subject choice). It finds that the transitions within- and post-school are more powerfully influenced by students' academic ability than by socioeconomic background. Furthermore, subject choice has strong impacts on the transitions. Similarly, Year 12 subject choice is only weakly predicted by socioeconomic background, and more strongly influenced by ability and occupational interests. In turn, occupational interests are largely independent of socioeconomic background. The EMI thesis is not supported. PMID:24090857

  5. Mask CD uniformity improvement by electron scanning exposure based Global Loading Effect Correction

    NASA Astrophysics Data System (ADS)

    Li, Rivan; Tian, Eric; Shi, Irene; Guo, Eric; Lu, Max

    2015-07-01

    Critical Dimension (CD) Uniformity is one of the necessary parameters to assure good performance and reliable functionality of any integrated circuit (IC), and towards the advanced technology node 28nm and beyond, corresponding CD Uniformity becomes more and more crucial. It is found that bad mask CD Uniformity is a significant error source at 28nm process. The CD Uniformity on mask, if not controlled well, will badly impact wafer CD performance, and it has been well-studied that CD Uniformity issue from gate line-width in transistors would affect the device performance directly. In this paper we present a novel solution for mask global CD uniformity error correction, which is called as global loading effect correction (GLEC) method and applied nesting in the mask exposure map during the electron beam exposure. There are factors such as global chip layout, writing sequence and chip pattern density distribution (Global Loading), that work on the whole mask CD Uniformity, especially Global Loading is the key factor related to mask global CD error. From our experimental results, different pattern density distribution on mask significantly influenced the final mask CD Uniformity: the mask with undulating pattern density distribution provides much worse CD Uniformity than that with uniform one. Therefore, a GLEC model based on pattern density has been created to compensate the global error during the electron beam exposure, which has been proved to be efficacious to improve mask global CD Uniformity performance. Furthermore, it 's also revealed that pattern type is another important impact factor, and GLEC coefficient need be modified due to the specific pattern type (e.g. dense line-space only, iso-space only or an average of them) to improve the corresponding mask CD uniformity.

  6. Clinical Effect of Surgical Correction for Nasal Pathology on the Treatment of Obstructive Sleep Apnea Syndrome

    PubMed Central

    Park, Chong Yoon; Hong, Joon Hyeong; Lee, Jae Heon; Lee, Kyu Eun; Cho, Hyun Sang; Lim, Su Jin; Kwak, Jin Wook; Kim, Kyung Soo; Kim, Hyun Jik

    2014-01-01

    Objectives This study aimed to evaluate the hypothesis that relief of nasal obstruction in subjects with obstructive sleep apnea (OSA) would lead to reduce OSA severity and to discuss the available evidence on the clinical efficacy of nasal surgery as a treatment modality for OSA. Study Design Twenty-five subjects who had reduced patency of nasal cavity and narrowing of retroglossal or retropalatal airways were diagnosed with OSA and underwent nasal surgery, such as septoplasty or turbinoplasty to correct nasal pathologies. The effect of the surgery on nasal patency was quantified by measuring minimal cross-sectional area (MCA) using acoustic rhinometry. The watch-PAT-derived respiratory disturbance index (RDI), apnea and hypopnea index (AHI), lowest oxygen saturation, and valid sleep time were measured before and after nasal surgery. Results The present study shows that the AHI and RDI decreased significantly and the lowest oxygen saturation and valid sleep time rose after nasal surgery in 25 OSA subjects. In addition, a reduction in subjective symptoms was observed in subjects and mean MCA increased after nasal surgery. Fourteen subjects were classified as responders and 11 subjects as non-responders. Responders showed considerable improvement of their subjective symptoms and the AHI and RDI were significantly lower after surgery. We found that the changes between pre- and post-operative AHI and RDI values were minimal in 11 non-responders. However, daytime somnolence and REM sleep time improved after nasal surgery in non-responders. Conclusions Our study provides evidence that the surgical treatment of nasal pathology improves nasal airway patency and reduces OSA severity in 56% subjects. Furthermore, correction of nasal pathology appears to result in improved sleep quality in both responder and non-responders OSA subjects. PMID:24896824

  7. Isotopic effects in the neon fixed point: uncertainty of the calibration data correction

    NASA Astrophysics Data System (ADS)

    Steur, Peter P. M.; Pavese, Franco; Fellmuth, Bernd; Hermier, Yves; Hill, Kenneth D.; Seog Kim, Jin; Lipinski, Leszek; Nagao, Keisuke; Nakano, Tohru; Peruzzi, Andrea; Sparasci, Fernando; Szmyrka-Grzebyk, Anna; Tamura, Osamu; Tew, Weston L.; Valkiers, Staf; van Geel, Jan

    2015-02-01

    The neon triple point is one of the defining fixed points of the International Temperature Scale of 1990 (ITS-90). Although recognizing that natural neon is a mixture of isotopes, the ITS-90 definition only states that the neon should be of ‘natural isotopic composition’, without any further requirements. A preliminary study in 2005 indicated that most of the observed variability in the realized neon triple point temperatures within a range of about 0.5 mK can be attributed to the variability in isotopic composition among different samples of ‘natural’ neon. Based on the results of an International Project (EUROMET Project No. 770), the Consultative Committee for Thermometry decided to improve the realization of the neon fixed point by assigning the ITS-90 temperature value 24.5561 K to neon with the isotopic composition recommended by IUPAC, accompanied by a quadratic equation to take the deviations from the reference composition into account. In this paper, the uncertainties of the equation are discussed and an uncertainty budget is presented. The resulting standard uncertainty due to the isotopic effect (k = 1) after correction of the calibration data is reduced to (4 to 40) μK when using neon of ‘natural’ isotopic composition or to 30 μK when using 20Ne. For comparison, an uncertainty component of 0.15 mK should be included in the uncertainty budget for the neon triple point if the isotopic composition is unknown, i.e. whenever the correction cannot be applied.

  8. Effects of background noise on the response of rat and cat motoneurones to excitatory current transients.

    PubMed Central

    Poliakov, A V; Powers, R K; Sawczuk, A; Binder, M D

    1996-01-01

    1. We studied the responses of rat hypoglossal motoneurones to excitatory current transients (ECTs) using a brainstem slice preparation. Steady, repetitive discharge at rates of 12-25 impulses s-1 was elicited from the motoneurones by injecting long (40 s) steps of constant current. Poisson trains of the ECTs were superimposed on these steps. The effects of additional synaptic noise was simulated by adding a zero-mean random process to the stimuli. 2. We measured the effects of the ECTs on motoneurone discharge probability by compiling peristimulus time histograms (PSTHs) between the times of occurrence of the ECTs and the motoneurone spikes. The ECTs produced modulation of motoneurone discharge similar to that produced by excitatory postsynaptic currents. 3. The addition of noise altered the pattern of the motoneurone response to the current transients: both the amplitude and the area of the PSTH peaks decreased as the power of the superimposed noise was increased. Noise tended to reduce the efficacy of the ECTs, particularly when the motoneurones were firing at lower frequencies. Although noise also increased the firing frequency of the motoneurones slightly, the effects of noise on ECT efficacy did not simply result from noise-induced changes in mean firing rate. 4. A modified version of the experimental protocol was performed in lumbar motoneurones of intact, pentobarbitone-anaesthetized cats. These recordings yielded results similar to those obtained in rat hypoglossal motoneurones in vitro. 5. Our results suggest that the presence of concurrent synaptic inputs reduces the efficacy of any one input. The implications of this change in efficacy and the possible underlying mechanisms are discussed. PMID:8866358

  9. Effect of anolyte on background microflora, Salmonella, and Listeria monocytogenes on catfish fillets.

    PubMed

    Rajkowski, Kathleen T; Sommers, Christopher H

    2012-04-01

    Near-neutral electrolyzed water (anolyte), having a pH of 6.0 to 6.5 ± 0.02, oxidation reduction potential of greater than 700 mV, and a residual chlorine level of 10 to 200 ppm, was reported to have a potential use to decontaminate food surfaces. An electrolyzing cell was developed that is capable of producing neutral electrolyzed water containing a chlorine level of greater than 700 ppm in the form of hypochlorous acid (anolyte). Anolyte with a chlorine level of 300 ppm was used to determine its effect on Salmonella and Listeria monocytogenes cells after a 3-min contact. Transmission electron micrograph results showed disruption of the outer cellular membrane for both bacteria. The anolyte (300 ppm) was used as a washing solution to decontaminate catfish fillets inoculated with either Salmonella or L. monocytogenes. After a 3-min contact time with the anolyte, there was a 1-log reduction for Salmonella, and after 8 days of refrigerated storage (4°C), this bacterial reduction was maintained. There was no reduction of L. monocytogenes on the catfish fillet surfaces. The anolyte was an effective wash solution for Salmonella reduction on the catfish fillet surfaces. PMID:22488069

  10. The optimized effective potential and the self-interaction correction in density functional theory: Application to molecules

    NASA Astrophysics Data System (ADS)

    Garza, Jorge; Nichols, Jeffrey A.; Dixon, David A.

    2000-05-01

    The Krieger, Li, and Iafrate approximation to the optimized effective potential including the self-interaction correction for density functional theory has been implemented in a molecular code, NWChem, that uses Gaussian functions to represent the Kohn and Sham spin-orbitals. The differences between the implementation of the self-interaction correction in codes where planewaves are used with an optimized effective potential are discussed. The importance of the localization of the spin-orbitals to maximize the exchange-correlation of the self-interaction correction is discussed. We carried out exchange-only calculations to compare the results obtained with these approximations, and those obtained with the local spin density approximation, the generalized gradient approximation and Hartree-Fock theory. Interesting results for the energy difference (GAP) between the highest occupied molecular orbital, HOMO, and the lowest unoccupied molecular orbital, LUMO, (spin-orbital energies of closed shell atoms and molecules) using the optimized effective potential and the self-interaction correction have been obtained. The effect of the diffuse character of the basis set on the HOMO and LUMO eigenvalues at the various levels is discussed. Total energies obtained with the optimized effective potential and the self-interaction correction show that the exchange energy with these approximations is overestimated and this will be an important topic for future work.

  11. Understanding the electrolyte background for biochemical sensing with ion-sensitive field-effect transistors.

    PubMed

    Tarasov, Alexey; Wipf, Mathias; Stoop, Ralph L; Bedner, Kristine; Fu, Wangyang; Guzenko, Vitaliy A; Knopfmacher, Oren; Calame, Michel; Schönenberger, Christian

    2012-10-23

    Silicon nanowire field-effect transistors have attracted substantial interest for various biochemical sensing applications, yet there remains uncertainty concerning their response to changes in the supporting electrolyte concentration. In this study, we use silicon nanowires coated with highly pH-sensitive hafnium oxide (HfO(2)) and aluminum oxide (Al(2)O(3)) to determine their response to variations in KCl concentration at several constant pH values. We observe a nonlinear sensor response as a function of ionic strength, which is independent of the pH value. Our results suggest that the signal is caused by the adsorption of anions (Cl(-)) rather than cations (K(+)) on both oxide surfaces. By comparing the data to three well-established models, we have found that none of those can explain the present data set. Finally, we propose a new model which gives excellent quantitative agreement with the data. PMID:23016890

  12. Holographic p-wave superconductor models with Weyl corrections

    NASA Astrophysics Data System (ADS)

    Zhang, Lu; Pan, Qiyuan; Jing, Jiliang

    2015-04-01

    We study the effect of the Weyl corrections on the holographic p-wave dual models in the backgrounds of AdS soliton and AdS black hole via a Maxwell complex vector field model by using the numerical and analytical methods. We find that, in the soliton background, the Weyl corrections do not influence the properties of the holographic p-wave insulator/superconductor phase transition, which is different from that of the Yang-Mills theory. However, in the black hole background, we observe that similarly to the Weyl correction effects in the Yang-Mills theory, the higher Weyl corrections make it easier for the p-wave metal/superconductor phase transition to be triggered, which shows that these two p-wave models with Weyl corrections share some similar features for the condensation of the vector operator.

  13. Epistasis between antibiotic resistance mutations and genetic background shape the fitness effect of resistance across species of Pseudomonas.

    PubMed

    Vogwill, T; Kojadinovic, M; MacLean, R C

    2016-05-11

    Antibiotic resistance often evolves by mutations at conserved sites in essential genes, resulting in parallel molecular evolution between divergent bacterial strains and species. Whether these resistance mutations are having parallel effects on fitness across bacterial taxa, however, is unclear. This is an important point to address, because the fitness effects of resistance mutations play a key role in the spread and maintenance of resistance in pathogen populations. We address this idea by measuring the fitness effect of a collection of rifampicin resistance mutations in the β subunit of RNA polymerase (rpoB) across eight strains that span the diversity of the genus Pseudomonas We find that almost 50% of rpoB mutations have background-dependent fitness costs, demonstrating that epistatic interactions between rpoB and the rest of the genome are common. Moreover, epistasis is typically strong, and it is the dominant genetic determinant of the cost of resistance mutations. To investigate the functional basis of epistasis, and because rpoB plays a central role in transcription, we measured the effects of common rpoB mutations on transcriptional efficiency across three strains of Pseudomonas Transcriptional efficiency correlates strongly to fitness across strains, and epistasis arises because individual rpoB mutations have differential effects on transcriptional efficiency in different genetic backgrounds. PMID:27170722

  14. Epistasis between antibiotic resistance mutations and genetic background shape the fitness effect of resistance across species of Pseudomonas

    PubMed Central

    Kojadinovic, M.; MacLean, R. C.

    2016-01-01

    Antibiotic resistance often evolves by mutations at conserved sites in essential genes, resulting in parallel molecular evolution between divergent bacterial strains and species. Whether these resistance mutations are having parallel effects on fitness across bacterial taxa, however, is unclear. This is an important point to address, because the fitness effects of resistance mutations play a key role in the spread and maintenance of resistance in pathogen populations. We address this idea by measuring the fitness effect of a collection of rifampicin resistance mutations in the β subunit of RNA polymerase (rpoB) across eight strains that span the diversity of the genus Pseudomonas. We find that almost 50% of rpoB mutations have background-dependent fitness costs, demonstrating that epistatic interactions between rpoB and the rest of the genome are common. Moreover, epistasis is typically strong, and it is the dominant genetic determinant of the cost of resistance mutations. To investigate the functional basis of epistasis, and because rpoB plays a central role in transcription, we measured the effects of common rpoB mutations on transcriptional efficiency across three strains of Pseudomonas. Transcriptional efficiency correlates strongly to fitness across strains, and epistasis arises because individual rpoB mutations have differential effects on transcriptional efficiency in different genetic backgrounds. PMID:27170722

  15. Optimising ketocarotenoid production in potato tubers: effect of genetic background, transgene combinations and environment.

    PubMed

    Campbell, Raymond; Morris, Wayne L; Mortimer, Cara L; Misawa, Norihiko; Ducreux, Laurence J M; Morris, Jenny A; Hedley, Pete E; Fraser, Paul D; Taylor, Mark A

    2015-05-01

    Astaxanthin is a high value carotenoid produced by some bacteria, a few green algae, several fungi but only a limited number of plants from the genus Adonis. Astaxanthin has been industrially exploited as a feed supplement in poultry farming and aquaculture. Consumption of ketocarotenoids, most notably astaxanthin, is also increasingly associated with a wide range of health benefits, as demonstrated in numerous clinical studies. Currently astaxanthin is produced commercially by chemical synthesis or from algal production systems. Several studies have used a metabolic engineering approach to produce astaxanthin in transgenic plants. Previous attempts to produce transgenic potato tubers biofortified with astaxanthin have met with limited success. In this study we have investigated approaches to optimising tuber astaxanthin content. It is demonstrated that the selection of appropriate parental genotype for transgenic approaches and stacking carotenoid biosynthetic pathway genes with the cauliflower Or gene result in enhanced astaxanthin content, to give six-fold higher tuber astaxanthin content than has been achieved previously. Additionally we demonstrate the effects of growth environment on tuber carotenoid content in both wild type and astaxanthin-producing transgenic lines and describe the associated transcriptome and metabolome restructuring. PMID:25804807

  16. Convolution effect on TCR log response curve and the correction method for it

    NASA Astrophysics Data System (ADS)

    Chen, Q.; Liu, L. J.; Gao, J.

    2016-09-01

    Through-casing resistivity (TCR) logging has been successfully used in production wells for the dynamic monitoring of oil pools and the distribution of the residual oil, but its vertical resolution has limited its efficiency in identification of thin beds. The vertical resolution is limited by the distortion phenomenon of vertical response of TCR logging. The distortion phenomenon was studied in this work. It was found that the vertical response curve of TCR logging is the convolution of the true formation resistivity and the convolution function of TCR logging tool. Due to the effect of convolution, the measurement error at thin beds can reach 30% or even bigger. Thus the information of thin bed might be covered up very likely. The convolution function of TCR logging tool was obtained in both continuous and discrete way in this work. Through modified Lyle-Kalman deconvolution method, the true formation resistivity can be optimally estimated, so this inverse algorithm can correct the error caused by the convolution effect. Thus it can improve the vertical resolution of TCR logging tool for identification of thin beds.

  17. Effects of Degree of Surgical Correction for Flatfoot Deformity in Patient-Specific Computational Models.

    PubMed

    Spratley, E M; Matheis, E A; Hayes, C W; Adelaar, R S; Wayne, J S

    2015-08-01

    A cohort of adult acquired flatfoot deformity rigid-body models was developed to investigate the effects of isolated tendon transfer with successive levels of medializing calcaneal osteotomy (MCO). Following IRB approval, six diagnosed flatfoot sufferers were subjected to magnetic resonance imaging (MRI) and their scans used to derive patient-specific models. Single-leg stance was modeled, constrained solely through physiologic joint contact, passive soft-tissue tension, extrinsic muscle force, body weight, and without assumptions of idealized mechanical joints. Surgical effect was quantified using simulated mediolateral (ML) and anteroposterior (AP) X-rays, pedobarography, soft-tissue strains, and joint contact force. Radiographic changes varied across states with the largest average improvements for the tendon transfer (TT) + 10 mm MCO state evidenced through ML and AP talo-1st metatarsal angles. Interestingly, 12 of 14 measures showed increased deformity following TT-only, though all increases disappeared with inclusion of MCO. Plantar force distributions showed medial forefoot offloading concomitant with increases laterally such that the most corrected state had 9.0% greater lateral load. Predicted alterations in spring, deltoid, and plantar fascia soft-tissue strain agreed with prior cadaveric and computational works suggesting decreased strain medially with successive surgical repair. Finally, joint contact force demonstrated consistent medial offloading concomitant with variable increases laterally. Rigid-body modeling thus offers novel advantages for the investigation of foot/ankle biomechanics not easily measured in vivo. PMID:25465617

  18. The Effects of Foreign Language Anxiety on EFL Learners' Perceptions of Oral Corrective Feedback

    ERIC Educational Resources Information Center

    Rassaei, Ehsan

    2015-01-01

    The study reported in this paper explored if learners' perceptions of two types of oral corrective feedback, recasts, and metalinguistic feedback, are influenced by their foreign language anxiety in classrooms. Corrective feedback was provided to English as a foreign language (EFL) learners who were homogeneous with regard to their proficiency…

  19. The effect and correction of coupling generated by the RHIC triplet quadrupoles

    SciTech Connect

    Pilat, F.; Peggs, S.; Tepikian, S.; Trbojevic, D.; Wei, J.

    1995-05-01

    This study explores the possibility of operating the nominal RHIC coupling correction system in local decoupling mode, where a subset of skew quadrupoles are independently set by minimizing the coupling as locally measured by beam position monitors. The goal is to establish a correction procedure for the skew quadrupole errors in the interaction region triplets that does not rely on a priori knowledge of the individual errors. After a description of the present coupling correction scheme envisioned for RHIC, the basics of the local decoupling method will be briefly recalled in the context of its implementation in the TEAPOT simulation code as well as operationally. The method is then applied to the RHIC lattice: a series of simple tests establish that single triplet skew quadrupole errors can be corrected by local decoupling. More realistic correction schemes are then studied in order to correct distributed sources of skew quadrupole errors: the machine can be decoupled either by pure local decoupling or by a combination of global (minimum tune separation) and local decoupling. The different correction schemes are successively validated and evaluated by standard RHIC simulation runs with the complete set of errors and corrections. The different solutions and results are finally discussed together with their implications for the hardware.

  20. Improved correction for the tissue fraction effect in lung PET/CT imaging

    NASA Astrophysics Data System (ADS)

    Holman, Beverley F.; Cuplov, Vesna; Millner, Lynn; Hutton, Brian F.; Maher, Toby M.; Groves, Ashley M.; Thielemans, Kris

    2015-09-01

    Recently, there has been an increased interest in imaging different pulmonary disorders using PET techniques. Previous work has shown, for static PET/CT, that air content in the lung influences reconstructed image values and that it is vital to correct for this ‘tissue fraction effect’ (TFE). In this paper, we extend this work to include the blood component and also investigate the TFE in dynamic imaging. CT imaging and PET kinetic modelling are used to determine fractional air and blood voxel volumes in six patients with idiopathic pulmonary fibrosis. These values are used to illustrate best and worst case scenarios when interpreting images without correcting for the TFE. In addition, the fractional volumes were used to determine correction factors for the SUV and the kinetic parameters. These were then applied to the patient images. The kinetic parameters K1 and Ki along with the static parameter SUV were all found to be affected by the TFE with both air and blood providing a significant contribution to the errors. Without corrections, errors range from 34-80% in the best case and 29-96% in the worst case. In the patient data, without correcting for the TFE, regions of high density (fibrosis) appeared to have a higher uptake than lower density (normal appearing tissue), however this was reversed after air and blood correction. The proposed correction methods are vital for quantitative and relative accuracy. Without these corrections, images may be misinterpreted.

  1. Differential Effects of Focused and Unfocused Written Correction on the Accurate Use of Grammatical Forms by Adult ESL Learners

    ERIC Educational Resources Information Center

    Sheen, Younghee; Wright, David; Moldawa, Anna

    2009-01-01

    Building on Sheen's (2007) study of the effects of written corrective feedback (CF) on the acquisition of English articles, this article investigated whether direct focused CF, direct unfocused CF and writing practice alone produced differential effects on the accurate use of grammatical forms by adult ESL learners. Using six intact adult ESL…

  2. An Evaluation of Retrieval Effectiveness Using Spelling-Correction and String-Similarity Matching Methods on Malay Texts.

    ERIC Educational Resources Information Center

    Abu Bakar, Zainab; Sembok, Tengku Mohd T.; Yusoff, Mohammed

    2000-01-01

    Evaluates the effectiveness of spelling-correction and string-similarity matching methods in retrieving similar words in a Malay dictionary associated with a set of query words. Describes experiments that showed the best search combination used a stemming algorithm, and calculates retrieval effectiveness and relevant means measures from weighted…

  3. The Effect of Error Correction vs. Error Detection on Iranian Pre-Intermediate EFL Learners' Writing Achievement

    ERIC Educational Resources Information Center

    Abedi, Razie; Latifi, Mehdi; Moinzadeh, Ahmad

    2010-01-01

    This study tries to answer some ever-existent questions in writing fields regarding approaching the most effective ways to give feedback to students' errors in writing by comparing the effect of error correction and error detection on the improvement of students' writing ability. In order to achieve this goal, 60 pre-intermediate English learners…

  4. Station Correction Uncertainty in Multiple Event Location Algorithms and the Effect on Error Ellipses

    SciTech Connect

    Erickson, Jason P.; Carlson, Deborah K.; Ortiz, Anne; Hutchenson, Kevin; Oweisny, Linda; Kraft, Gordon; Anderson, Dale N.; Tinker, Mark

    2003-10-30

    Accurate location of seismic events is crucial for nuclear explosion monitoring. There are several sources of error in seismic location that must be taken into account to obtain high confidence results. Most location techniques account for uncertainties in the phase arrival times (measurement error) and the bias of the velocity model (model error), but they do not account for the uncertainty of the velocity model bias. By determining and incorporating this uncertainty in the location algorithm we seek to improve the accuracy of the calculated locations and uncertainty ellipses. In order to correct for deficiencies in the velocity model, it is necessary to apply station specific corrections to the predicted arrival times. Both master event and multiple event location techniques assume that the station corrections are known perfectly, when in reality there is an uncertainty associated with these corrections. For multiple event location algorithms that calculate station corrections as part of the inversion, it is possible to determine the variance of the corrections. The variance can then be used to weight the arrivals associated with each station, thereby giving more influence to stations with consistent corrections. We have modified an existing multiple event location program (based on PMEL, Pavlis and Booker, 1983). We are exploring weighting arrivals with the inverse of the station correction standard deviation as well using the conditional probability of the calculated station corrections. This is in addition to the weighting already given to the measurement and modeling error terms. We re-locate a group of mining explosions that occurred at Black Thunder, Wyoming, and compare the results to those generated without accounting for station correction uncertainty.

  5. [An improved physical model to correct topographic effects in remotely sensed imagery].

    PubMed

    Zhang, Zhao-ming; He, Guo-jin; Liu, Ding-sheng; Wang, Xiao-qin; Jiang, Hong

    2010-07-01

    Topographic correction for remotely sensed imagery is an important preprocessing step in order to improve the retrieval accuracy of land surface spectral reflectance in mountainous area. Various kinds of topographic correction models have been proposed in the literature. Each model has its advantages and limitations. In consideration of the limitations of the topographic correction models in the literature, an improved Shepherd topographic correction model is proposed in this paper. Diffuse irradiance is an essential factor in the physically based topographic correction model. While in the Shepherd model (originally proposed by Shepherd et al. in 2003), accuracy of the method to compute the diffuse irradiance is relatively low; therefore, the accuracy of the land surface spectral reflectance retrieved with the Shepherd model is impacted. In order to improve the accuracy of diffuse irradiance, hence the accuracy of land surface spectral reflectance, a different method (named the Perez model), is used to obtain the diffuse irradiance with higher accuracy in the improved Shepherd model. Landsat 5 Thematic Mapper (TM) imagery acquired on July 12th 2006, over the mountainous areas in the north of Beijing city, was employed to retrieve land surface spectral reflectance with the improved Shepherd topographic correction model and 6S (Second Simulation of the Satellite Signal in the Solar Spectrum) atmospheric radiative transfer model. Correction results were tested with three different methods. Testing result shows that the improved Shepherd topographic correction model can achieve a good correction result and is better than Shepherd and C topographic correction model. What is more, this improved model is physically based and can be applied to all kinds of optical satellite imagery. PMID:20827982

  6. Effects of fast-acting high-frequency compression on the intelligibility of speech in steady and fluctuating background sounds.

    PubMed

    Stone, M A; Moore, B C; Wojtczak, M; Gudgin, E

    1997-08-01

    This study examines whether speech intelligibility in background sounds can be improved for persons with loudness recruitment by the use of fast-acting compression applied at high frequencies, when the overall level of the sounds is held constant by means of a slow-acting automatic gain control (AGC) system and when appropriate frequency-response shaping is applied. Two types of fast-acting compression were used in the high-frequency channel of a two-channel system: a compression limiter with a 10:1 compression ratio and with a compression threshold about 9 dB below the peak level of the signal in the high-frequency channel; and a wide dynamic range compressor with a 2:1 compression ratio and with the compression threshold about 24 dB below the peak level of the signal in the high-frequency channel. A condition with linear processing in the high-frequency channel was also used. Speech reception thresholds (SRTs) were measured for two background sounds: a steady speech-shaped noise and a single male talker. All subjects had moderate-to-severe sensorineural hearing loss. Three different types of speech material were used: the adaptive sentence lists (ASL), the Bamford-Kowal-Bench (BKB) sentence lists and the Boothroyd word lists. For the steady background noise, the compression generally led to poorer performance than for the linear condition, although the deleterious effect was only significant for the 10:1 compression ratio. For the background of a single talker, the compression had no significant effect except for the ASL sentences, where the 10:1 compression gave significantly better performance than the linear condition. Overall, the results did not show any clear benefits of the fast-acting compression, possibly because the slow-acting AGC allowed the use of gains in the linear condition that were markedly higher than would normally be used with linear hearing aids. PMID:9307821

  7. Dead time effect on the Brewer measurements: correction and estimated uncertainties

    NASA Astrophysics Data System (ADS)

    Fountoulakis, I.; Redondas, A. M.; Bais, A. F.; Rodriguez-Franco, J. J.; Fragkos, K.; Cede, A.

    2015-12-01

    Brewer spectrophotometers are widely used instruments which perform spectral measurements of the direct and the global solar UV irradiance. By processing these measurements a variety of secondary products can be derived such as the total columns of ozone, sulfur dioxide and nitrogen dioxide, and aerosol optical properties. Estimating and limiting the uncertainties of the final products is of critical importance. High quality data have a lot of applications and can provide accurate estimations of trends. The dead time is characteristic for each instrument and non-proper correction of the raw data for its effect may lead to important errors in the final products. It may change with time and the currently used methodology is not always sufficient to accurately determine the correct dead time. For specific cases, such as for low ozone slant columns and high intensities of the direct solar irradiance, the error in the retrieved TOC, due a 10 ns change in the dead time from its nominal value, is found to be up to 5 %. The error in the calculation of UV irradiance is about 3-4 % near the maximum operational limit of light intensities. While in the existing documentation it is indicated that the dead time effects are important when the error in the used value is greater than 2 ns, we found that for single monochromator Brewers a 2 ns error in the dead time may lead to uncertainties above the limit of 1 % in the calculation of TOC; thus the tolerance limit should be lowered. A new routine for the determination of the dead time from direct solar irradiance measurements has been created and tested and a validation of the operational algorithm has been performed. Additionally, new methods for the estimation and the validation of the dead time have been developed and are analytically described. Therefore, the present study in addition to highlighting the importance of the dead time for the processing of Brewer datasets, also provide useful information for their quality control

  8. Effect of the ponderomotive force caused by Alfvén waves on a background plasma in the dayside magnetosphere

    NASA Astrophysics Data System (ADS)

    Nekrasov, A. K.; Feygin, F. Z.

    2016-07-01

    The effect of the ponderomotive force on the background plasma modification near magnetic holes, which form at the dayside magnetospheric boundary under the action of the solar wind, has been studied. It was shown that this effect results in a substantial increase in a nonlinear plasma density disturbance. The dependence of the ponderomotive force on the magnetospheric parameters (the magnetic longitude, distance from the Earth's surface, ratio of the wave frequency to the proton gyrofrequency, and ionospheric ion cyclotron wave amplitude) has been studied. Nonlinear plasma density disturbances will be maximal in the region of magnetic holes, which are located in the dayside magnetosphere at λ ~ 0°-30° geomagnetic longitudes (λ = 0° corresponds to noon), where the effect of the solar wind pressure is maximal. A similar effect is also observed in the dependence of a nonlinear plasma density disturbance on other magnetospheric parameters.

  9. Enhanced nitrogen deposition exacerbates the negative effect of increasing background ozone in Dactylis glomerata, but not Ranunculus acris.

    PubMed

    Wyness, Kirsten; Mills, Gina; Jones, Laurence; Barnes, Jeremy D; Jones, Davey L

    2011-10-01

    The combined impacts of simulated increased nitrogen (N) deposition (75 kg Nha(-1)yr (-1)) and increasing background ozone (O(3)) were studied using two mesotrophic grassland species (Dactylis glomerata and Ranunculus acris) in solardomes, by means of eight O(3) treatments ranging from 15.5 ppb to 92.7 ppb (24h average mean). A-C(i) curves were constructed for each species to gauge effects on photosynthetic efficiency and capacity, and effects on biomass partitioning were determined after 14 weeks. Increasing the background concentration of O(3) reduced the healthy above ground and root biomass of both species, and increased senesced biomass. N fertilisation increased biomass production in D. glomerata, and a significantly greater than additive effect of O(3) and N on root biomass was evident. In contrast, R. acris biomass was not affected by high N. The study shows the combined effects of these pollutants have differential implications for carbon allocation patterns in common grassland species. PMID:21741736

  10. The flip-over effect in pulsed laser deposition: Is it relevant at high background gas pressures?

    NASA Astrophysics Data System (ADS)

    Ojeda-G-P, Alejandro; Schneider, Christof W.; Döbeli, Max; Lippert, Thomas; Wokaun, Alexander

    2015-12-01

    In pulsed laser deposition the use of a rectangular or elliptical beam spot with a non 1:1 aspect ratio leads to the so called flip-over effect. Here, the longest dimension of the laser spot results in the shortest direction of plasma plume expansion. This effect has been mainly reported for vacuum depositions of single element targets and is particularly noticeable when the aspect ratio of the beam spot is large. We investigate the flip-over effect in vacuum and at three relevant background-gas pressures for pulsed laser deposition using a La0.4Ca0.6MnO3 target by measuring the thickness dependence of the deposited material as a function of angle. The film thicknesses and compositions are determined by Rutherford backscattering and argon is used to reduce the influence of additional chemical reactions in the plasma. The results show the prevalence of the flip-over effect for all pressures except for the highest, i.e. 1 × 10-1 mbar, where the film thickness is constant for all angles. The composition profiles show noticeable compositional variations of up to 30% with respect to the target material depending on the background gas pressure, the angular location, and the laser spot dimensions.

  11. Investigation of effects of background water on upwelled reflectance spectra and techniques for analysis of dilute primary-treated sewage sludge

    NASA Technical Reports Server (NTRS)

    Whitlock, C. H.; Usry, J. W.; Witte, W. G.; Farmer, F. H.; Gurganus, E. A.

    1979-01-01

    In an effort to improve understanding of the effects of variations in background water on reflectance spectra, laboratory tests were conducted with various concentrations of sewage sludge diluted with several types of background water. The results from these tests indicate that reflectance spectra for sewage-sludge mixtures are dependent upon the reflectance of the background water. Both the ratio of sewage-sludge reflectance to background-water reflectance and the ratio of the difference in reflectance to background-water reflectance show spectral variations for different turbid background waters. The difference in reflectance is the only parameter considered.

  12. [Pre-and probiotics effectiveness in intestine microbiocenosis correction in patients after hemicolectomy].

    PubMed

    Li, A I; Sil'vestrova, S Iu

    2011-01-01

    Normal microflora plays a key role in ensuring and maintaining the health of human body. Currently, much attention is paid not only to rational, but the so-called optimal, or health nutrition, which includes individual selection of food, the most satisfying human needs for energy, plastic and regulatory components. The aim of our study was to evaluate the effectiveness of pre-and probiotics in correction of the intestine microbiocenosis, effect on the rate of the hyperendotoxemia and related functional changes in the liver and lipid metabolism. In our study, we identified changesof the intestine microbiocenosis, which led to endotoxemia to develop, and the associated changes in liver enzymes and lipid blood composition in patients after various variants of the hemicolectomy. During treatment were selected 50 patients with dysbiosis 2 - 4-th degree who underwent hemicolectomy. In the 1st groupwere patients (25 pat.) with the prevailing complaints of constipation that were performed therapy with lactulose prebiotics (Dyufalak) at 20 - 30 ml per day for 3 months. In the 2nd group were patients (25 pat.) with complaints of diarrhea and was conducted therapy with bifiform probiotic in a daily dose to 2 capsules 2 times a day for 3 months. The results of studies performed after treatment showed that the admission of pro-and prebiotics in patients after hemicolectomy, has a high efficiency in micro biocenosis restoring and had a positive effect not only on bacterial composition of the microflora, but also on the functional state of the liver and lipid levels in patients serum. PMID:22168078

  13. Effects of Background Lighting Color and Movement Distance on Reaching Times Among Participants With Low Vision, Myopia, and Normal Vision.

    PubMed

    Chen, Chun-Fu; Huang, Kuo-Chen

    2016-04-01

    This study investigated the effects of target distance (30, 35, and 40 cm) and the color of background lighting (red, green, blue, and yellow) on the duration of movements made by participants with low vision, myopia, and normal vision while performing a reaching task; 48 students (21 women, 27 men; M age = 21.8 year, SD = 2.4) participated in the study. Participants reached for a target (a white LED light) whose vertical position varied randomly across trials, ranging in distance from 30 to 40 cm. Movement time was analyzed using a 3 (participant group) × [4 (color of background lighting) × 3 (movement distance)] mixed-design ANOVA model. Results indicated longer times for completing a reaching movement when: participants belonged to the low vision group; the target distance between the starting position and the target position was longer (40 cm); and the reaching movement occurred in the red-background lighting condition. These results are particularly relevant for situations in which a user is required to respond to a signal by reaching toward a button or an icon. PMID:27166331

  14. Effect of background gas pressure and laser pulse intensity on laser induced plasma radiation of copper samples

    NASA Astrophysics Data System (ADS)

    Mehrabian, S.; Aghaei, M.; Tavassoli, S. H.

    2010-04-01

    Study of laser induced plasma emission of Cu in one dimension is numerically carried out. Effects of different background gas pressure (He), 100, 500, and 760 torr, and laser pulse intensities, 0.5, 0.7, and 1 GW/cm2, on the plasma emission as well as ablation processes are investigated. Under a specified condition, heat conduction equation in the target accompanied with gas dynamic equations in the plume is solved simultaneously. The mentioned equations are coupled to each other through the Knudsen layer conditions and the energy and mass balances at the interface between the target and the vapor. The Bremsstrahlung radiation of plasma and the spectral emission of copper atoms are studied under various background gas pressure and laser pulse intensities. Furthermore, number density of He, Cu, and the electron, pressure, and temperature of the plume under various conditions are obtained. In the early time after laser pulse, plasma radiation is mainly due to the Bremsstrahlung radiation while after some 10 ns, the plasma radiation is dominated by spectral emission of Cu atoms. A similar uncoupling is observed spatially. The Bremsstrahlung emission is dominant near the sample surface while at farther points the spectral emission is the dominant one. By increase in the background pressure and also the pulse intensity, the dominancy of the spectral emission would occur later in time and farther in position.

  15. Proof-to-Print Match: Effectiveness of Substrate-Corrected Colorimetric Aims in Soft Proofing

    NASA Astrophysics Data System (ADS)

    Cheng, Peng

    Soft proofing is an effective solution for clients and printers that decreases production cost and cycle time. However, print buyers are increasingly specifying brighter papers, which contain optical brightening agents (OBAs). One potential concern facing adopters of soft proofing systems is that they fail to consider the influence of OBA when rendering color images. Proofing systems are largely based on existing published specifications and their ICC profiles. These specifications and ICC profiles --- such as SWOP 3 and GRACoL 2006--- do not account for the influence of OBA-loaded printing papers, and therefore could cause a mismatch between the soft proof and the final print. To improve the soft proofing performance, it is important to account for the influence of OBA in printed color and in soft proofing. This research project investigated the use of the substrate-corrected colorimetric aims (SCCA) as the source ICC profile to improve proofing color accuracy. By conducting psychometric experiments and analyzing with Chi-Square statistic, the research concludes that (a) OBA causes the mismatch between the default soft proof and the OBA-loaded print; (b) source ICC profiles, built from both a fully characterized dataset and an SCCA solution, can improve color match between the soft proof and the OBA-loaded print; and (c) color match between the soft proof and the print is image-dependent.

  16. On the Efficacy of Correcting for Refractive Effects in Iris Recognition

    SciTech Connect

    Price, Jeffery R; Gee, Timothy Felix; Paquit, Vincent C; Tobin Jr, Kenneth William

    2007-01-01

    In this study, we aim to determine if iris recognition accuracy might be improved by correcting for the refractive effects of the human eye when the optical axes of the eye and camera are misaligned. We undertake this investigation using an anatomically-approximated, three-dimensional model of the human eye and ray-tracing. We generate synthetic iris imagery from different viewing angles using first a simple pattern of concentric rings on the iris for analysis, and then stone-like texture maps on the iris for experimentation. We estimate the distortion from the concentric-ring iris images and use the results to guide the sampling of xtextured iris images that are distorted by refraction. Using the well-known Gabor filter phase quantization approach, our results indicate that the Hamming distances between iris signatures from different viewing angles can be significantly reduced by accounting for refraction. Over our experimental conditions comprising viewing angles from 0 to 60 degrees, Hamming distances are always reduced, with a median reduction of 7.19% and a maximum reduction of 19.0%.

  17. A photoelastic-modulator-based motional Stark effect polarimeter for ITER that is insensitive to polarized broadband background reflections

    NASA Astrophysics Data System (ADS)

    Thorman, A.; Michael, C.; De Bock, M.; Howard, J.

    2016-07-01

    A motional Stark effect polarimeter insensitive to polarized broadband light is proposed. Partially polarized background light is anticipated to be a significant source of systematic error for the ITER polarimeter. The proposed polarimeter is based on the standard dual photoelastic modulator approach, but with the introduction of a birefringent delay plate, it generates a sinusoidal spectral filter instead of the usual narrowband filter. The period of the filter is chosen to match the spacing of the orthogonally polarized Stark effect components, thereby increasing the effective signal level, but resulting in the destructive interference of the broadband polarized light. The theoretical response of the system to an ITER like spectrum is calculated and the broadband polarization tolerance is verified experimentally.

  18. Age-Dependent Resistance to Excitotoxicity in Htt CAG140 Mice and the Effect of Strain Background

    PubMed Central

    Strong, Melissa K.; Southwell, Amber L.; Yonan, Jennifer M.; Hayden, Michael R.; MacGregor, Grant R.; Thompson, Leslie M.; Steward, Oswald

    2013-01-01

    Mouse strain background can influence vulnerability to excitotoxic neuronal cell death and potentially modulate phenotypes in transgenic mouse models of human disease. Evidence supports a contribution of excitotoxicity to the selective death of medium spiny neurons in Huntington’s disease (HD). Here, we assess whether strain differences in excitotoxic vulnerability influence striatal cell death in a knock-in mouse model of HD. Previous studies that evaluated resistance to excitotoxic lesions in several mouse models of HD had variable outcomes. In the present study, we directly compare one model on two different background strains to test the contribution of strain to excitotoxicity-mediated neurodegeneration. Mice of the FVB/N strain, which are highly vulnerable to excitotoxicity, become extremely resistant to quinolinic acid-induced striatal neurodegeneration with age, when carrying a huntingtin (Htt) allele expressing a HD transgene (CAG140). The resistance is much greater than the age-dependent resistance that has been previously reported in YAC128 mice. By 12 months of age, both heterozygous and homozygous FVB.CAG140 mice displayed virtually complete resistance to quinolinic acid-induced striatal neurodegeneration. A similar resistance develops in CAG140 mice on a C57BL/6N background although the effect size is smaller because C57BL/6N mice are already resistant due to genetic background. In a direct comparison with the YAC128 mice, FVB.CAG140 mice have greater resistance. FVB.CAG140 mice are also resistant to neurodegeneration following kainic acid-induced status epilepticus suggesting the existence of a common cellular mechanism that provides protection against multiple types of excitotoxic insult. These findings establish FVB.CAG140 mice as a useful model to investigate the cellular and molecular mechanisms that confer neuroprotection against excitotoxicity. PMID:23833693

  19. An effective method for on-line corrections of two-axes laser mount.

    NASA Astrophysics Data System (ADS)

    Lála, P.; Pivo, K.

    An algorithm for correction of two-axes laser mount direction and gates in case of atmospheric drag induced deviations from the predicted satellite motion is described. Results of numerical simulations are shown.

  20. Effects of Self-Instruction and Self-Correction Procedures on Handwriting Performance.

    ERIC Educational Resources Information Center

    Kosiewicz, Marianne Myron; And Others

    1982-01-01

    A reversal design with multiple baseline features was used to assess the efficacy of self-instructions, self-correction, and a combination of the two on a nine-year-old learning disabled boy's handwriting performance. (Author)