Sample records for energy detection threshold

  1. Dynamic Threshold for Morphological Change Detection Algorithm

    Microsoft Academic Search

    A. N. M. Rezaul Karim; M. G. R. Alam

    2009-01-01

    Vision-based systems for remote surveillance usually involve change detection algorithms for intruders, obstacles or irregularities detection. Real time applications require simple, fast and reliable algorithms for change detection methodology. Morphological change detection algorithm satisfies these requirements. Threshold is a very important issue for morphological change detection. Threshold is static in existing Morphological Change Detection Algorithm (12). We are introducing a

  2. Deriving Optimal Thresholds for Active Fire Detection

    Microsoft Academic Search

    Soo Chin Liew; Agnes Lim; Leong Keong Kwoh

    2006-01-01

    In this paper, the optimal threshold for fire detection is derived based on the probability density functions of the fire and background pixels. The threshold values and the commission and omission errors are computed according to several detection criteria: maximum likelihood, null-hypothesis testing, and minimum cost. This statistical approach enables the determination of optimal threshold value according to the specific

  3. Detection thresholds for spiral Glass patterns

    PubMed Central

    Seu, Lillian; Ferrera, Vincent P.

    2015-01-01

    We measured thresholds for the detection of spiral Glass patterns in the presence of random noise. The patterns were constructed so that the orientation content did not vary as a function of spiral angle or signal level. We found that spiral patterns had higher thresholds than either radial or concentric Glass patterns. The results support the idea that the human visual system is specialized to detect radial and concentric patterns. PMID:11738446

  4. Effects of threshold of hard cut based technique for advertisement detection in TV video streams

    Microsoft Academic Search

    Ashish Tanwer; Parminder Singh Reel

    2010-01-01

    Advertisement detection in a TV video recording\\/archiving system is a challenging task. In this paper, shot change (hard cut) detection that is based on ¿inter-frame difference¿, ¿normalized difference energy¿ and the ¿normalized sum of absolute differences¿ and its comparison with a threshold are discussed. The effects of changing video threshold on hard cut detection have been summarized. A threshold value

  5. Chemical sensing thresholds for mine detection dogs

    NASA Astrophysics Data System (ADS)

    Phelan, James M.; Barnett, James L.

    2002-08-01

    Mine detection dogs have been found to be an effective method to locate buried landmines. The capabilities of the canine olfaction method are from a complex combination of training and inherent capacity of the dog for odor detection. The purpose of this effort was to explore the detection thresholds of a limited group of dogs that were trained specifically for landmine detection. Soils were contaminated with TNT and 2,4-DNT to develop chemical vapor standards to present to the dogs. Soils contained ultra trace levels of TNT and DNT, which produce extremely low vapor levels. Three groups of dogs were presented the headspace vapors from the contaminated soils in work environments for each dog group. One positive sample was placed among several that contained clean soils and, the location and vapor source (strength, type) was frequently changed. The detection thresholds for the dogs were determined from measured and extrapolated dilution of soil chemical residues and, estimated soil vapor values using phase partitioning relationships. The results showed significant variances in dog sensing thresholds, where some dogs could sense the lowest levels and others had trouble with even the highest source. The remarkable ultra-trace levels detectable by the dogs are consistent with the ultra-trace chemical residues derived from buried landmines; however, poor performance may go unnoticed without periodic challenge tests at levels consistent with performance requirements.

  6. Detection thresholds for small haptic effects

    NASA Astrophysics Data System (ADS)

    Dosher, Jesse A.; Hannaford, Blake

    2002-02-01

    We are interested in finding out whether or not haptic interfaces will be useful in portable and hand held devices. Such systems will have severe constraints on force output. Our first step is to investigate the lower limits at which haptic effects can be perceived. In this paper we report on experiments studying the effects of varying the amplitude, size, shape, and pulse-duration of a haptic feature. Using a specific haptic device we measure the smallest detectable haptics effects, with active exploration of saw-tooth shaped icons sized 3, 4 and 5 mm, a sine-shaped icon 5 mm wide, and static pulses 50, 100, and 150 ms in width. Smooth shaped icons resulted in a detection threshold of approximately 55 mN, almost twice that of saw-tooth shaped icons which had a threshold of 31 mN.

  7. Sputtering Threshold Energies of Heavy Ions

    NASA Technical Reports Server (NTRS)

    Mantenieks, Maris A.

    1999-01-01

    Sputter erosion in ion thrusters has been measured in lifetests at discharge voltages as low as 25 V. Thruster operation at this discharge voltage results in component erosion rates sufficiently low to satisfy most mission requirements. It has been recognized that most of the internal sputtering in ion thrusters is done by doubly charged ions. Knowledge of the sputtering threshold voltage of a xenon molybdenum system would be beneficial in understanding the sputtering process as well as making more accurate calculations of the sputtering rates of ion thruster components. Sputtering threshold energies calculated from various formulations found in the literature results in values ranging from 28 to 200 eV. It is evident that some of these formulations cannot be relied upon to provide sputtering thresholds with any degree of accuracy. This paper re-examines the threshold energies measurements made in the early sixties by Askerov and Sena, and Stuart and Wehner. The threshold voltages as derived by Askerov and au have been reevaluated by using a different extrapolation method of sputter yields at low ion energies. The resulting threshold energies are in general similar to those measured by Stuart and Wehner. An empirical relationship is derived,for mercury and xenon ions for the ratio of the sputtering threshold energy to the sublimation energy as a function of the ratio of target to ion atomic mass.

  8. Remote Sensing Image Thresholding for Landslide Motion Detection

    Microsoft Academic Search

    Paul L. Rosin; Javier Hervas; Jose I. Barrdeo

    2000-01-01

    Techniques for performing change detection are developed and applied to digital aerial photographs of the Tessina landslide in Italy. Several automatic thresholding algorithms are compared, and a variety of lters are employed to eliminate much of the undesirable residual clutter in the thresholded dierence image, mainly as a result of natural vegetation and man-made land cover changes. This has enabled

  9. Reconfigurable energy efficient near threshold cache architectures

    Microsoft Academic Search

    Ronald G. Dreslinski; Gregory K. Chen; Trevor N. Mudge; David Blaauw; Dennis Sylvester; Krisztián Flautner

    2008-01-01

    Battery life is an important concern for modern embedded processors. Supply voltage scaling techniques can provide an order of magnitude reduction in energy. Current commercial memory technologies have been limited in the degree of supply voltage scaling that can be performed if they are to meet yield and reliability constraints. This has limited designers from exploring the near threshold operating

  10. N dynamics at and near threshold energies

    NASA Astrophysics Data System (ADS)

    Cieplý, A.; Smejkal, J.

    2010-04-01

    We have constructed effective separable meson-baryon potentials to match the equivalent chiral amplitudes up to the second order in external meson momenta. The parameters of the model were fitted to the threshold and low energy K-p data including the 1s level characteristics of the kaonic hydrogen atom. We discuss the results of our fits and use the model to calculate the ?? mass spectrum and the energy dependence of the K-N amplitudes.

  11. A gossiping protocol for detecting global threshold crossings

    Microsoft Academic Search

    Fetahi Wuhib; Mads Dam; Rolf Stadler

    2010-01-01

    We investigate the use of gossip protocols for the detection of network-wide threshold crossings. Our design goals are low protocol overhead, small detection delay, low probability of false positives and negatives, scalability, robustness to node failures and controllability of the trade-off between overhead and detection delay. Based on push-synopses, a gossip protocol introduced by Kempe et al., we present a

  12. Color-detection thresholds in rhesus macaque monkeys and humans.

    PubMed

    Gagin, Galina; Bohon, Kaitlin S; Butensky, Adam; Gates, Monica A; Hu, Jiun-Yiing; Lafer-Sousa, Rosa; Pulumo, Reitumetse L; Qu, Jane; Stoughton, Cleo M; Swanbeck, Sonja N; Conway, Bevil R

    2014-01-01

    Macaque monkeys are a model of human color vision. To facilitate linking physiology in monkeys with psychophysics in humans, we directly compared color-detection thresholds in humans and rhesus monkeys. Colors were defined by an equiluminant plane of cone-opponent color space. All subjects were tested on an identical apparatus with a four-alternative forced-choice task. Targets were 2° square, centered 2° from fixation, embedded in luminance noise. Across all subjects, the change in detection thresholds from initial testing to plateau performance (“learning”) was similar for +L ? M (red) colors and +M ? L (bluish-green) colors. But the extent of learning was higher for +S (lavender) than for ?S (yellow-lime); moreover, at plateau performance, the cone contrast at the detection threshold was higher for +S than for ?S. These asymmetries may reflect differences in retinal circuitry for S-ON and S-OFF. At plateau performance, the two species also had similar detection thresholds for all colors, although monkeys had shorter reaction times than humans and slightly lower thresholds for colors that modulated L/M cones. We discuss whether these observations, together with previous work showing that monkeys have lower spatial acuity than humans, could be accounted for by selective pressures driving higher chromatic sensitivity at the cost of spatial acuity amongst monkeys, specifically for the more recently evolved L ? M mechanism. PMID:25027164

  13. Evaluation of global image thresholding for change detection

    Microsoft Academic Search

    Paul L. Rosin; Efstathios V. Ioannidis

    2003-01-01

    The objective of this paper is to develop an approach for efficiently and quantitatively evaluating thresholding al- gorithms for change detection in a surveillance environment. Previous evaluation in the literature has either been subjective or small scale, in part due to the difficulties and\\/or the time and effort involved in determining appropriate ground truth. In comparison, our automated approach enables

  14. Effect of lateral perturbations on psychophysical acceleration detection thresholds

    PubMed Central

    Richerson, Samantha J; Morstatt, Scott M; O'Neal, Kristopher K; Patrick, Gloria; Robinson, Charles J

    2006-01-01

    Background In understanding how the human body perceives and responds to small slip-like motions, information on how one senses the slip is essential. The effect of aging and plantar sensory loss on detection of a slip can also be studied. Using psychophysical procedures, acceleration detection thresholds of small lateral whole-body perturbations were measured for healthy young adults (HYA), healthy older adults (HOA) and older adults with diabetic neuropathy (DOA). It was hypothesized that young adults would require smaller accelerations than HOA's and DOA's to detect perturbations at a given displacement. Methods Acceleration detection thresholds to whole-body lateral perturbations of 1, 2, 4, 8, and 16 mm were measured for HYAs, HOAs, and DOAs using psychophysical procedures including a two-alternative forced choice protocol. Based on the subject's detection of the previous trial, the acceleration magnitude of the subsequent trial was increased or decreased according to the parameter estimation by sequential testing methodology. This stair-stepping procedure allowed acceleration thresholds to be measured for each displacement. Results Results indicate that for lateral displacements of 1 and 2 mm, HOAs and DOAs have significantly higher acceleration detection thresholds than young adults. At displacements of 8 and 16 mm, no differences in threshold were found among groups or between the two perturbation distances. The relationship between the acceleration threshold and perturbation displacement is of particular interest. Peak acceleration thresholds of approximately 10 mm/s2 were found at displacements of 2, 4, 8, and 16 mm for HYAs; at displacements of 4, 8, and 16 mm for HOAs; and at displacements of 8 and 16 mm for DOAs. Thus, 2, 4, and 8 mm appear to be critical breakpoints for HYAs, HOAs, and DOAs respectively, where the psychometric curve deviated from a negative power law relationship. These critical breakpoints likely indicate a change in the physiology of the system as it responds to the stimuli. Conclusion As a function of age, the displacement at which the group deviates from a negative power law relationship increases from 2 mm to 4 mm. Additionally, the displacement at which subjects with peripheral sensory deficits deviate from the negative power law relations increases to 8 mm. These increases as a function of age and peripheral sensory loss may help explain the mechanism of falls in the elderly and diabetic populations. PMID:16433916

  15. Determining the threshold for asymmetry detection in facial expressions

    PubMed Central

    Hohman, Marc H.; Kim, Sang W.; Heller, Elizabeth S.; Frigerio, Alice; Heaton, James T.; Hadlock, Tessa A.

    2015-01-01

    Objective To quantify the threshold for human perception of asymmetry for eyebrow elevation, eye closure and smile, and to ascertain whether asymmetry detection thresholds and perceived severity of asymmetry differ in distinct facial zones. Study Design Online survey. Methods Photographs of a female volunteer performing eyebrow elevation, eye closure, and smile were digitally manipulated to introduce left-to-right asymmetry in 1mm increments from 0-6mm. One-hundred forty-five participants viewed these photographs using an online survey, measuring accuracy of asymmetry detection and perceived expression unnaturalness (on a scale of 1-5). Results Photographs of facial asymmetries were correctly judged as asymmetric over 90% of the time for 2mm or more of asymmetry in eyelid closure, and 3mm or more of asymmetry during smiling. Identification of eyebrow elevation asymmetry gradually rose from 23% correct to 97% correct across the range of 1-6mm of asymmetry. Greater degrees of asymmetry were ranked as significantly more unnatural across all expressions (3 tests; X2 (6, N = 145) = 405.52 to 656.27, all P<0.001). Conclusion Thresholds for asymmetry detection vary across different zones of the face, and once detected, asymmetry in eyelid position is perceived as more unnatural than asymmetries in either brow elevation or smile. These data will inform counseling of patients with segmental facial weakness and may provide more objective goals for facial reanimation procedures. PMID:23900726

  16. Improvement of radar target searches by a range dependent detection threshold or signal amplification

    Microsoft Academic Search

    E. Hanle

    1980-01-01

    The impact of signal amplification on the search for targets with different radar cross sections was studied. A clear presentation of the whole range dependence with minimum computing expense was obtained by restriction to single pulse operation. Through a suitable range controlled threshold with half the transmitting energy, the same detection probability at maximum range is obtained as with a

  17. Trend of contrast detection threshold with and without localization.

    PubMed

    Leong, David L; Rainford, Louise; Haygood, Tamara Miner; Whitman, Gary J; Geiser, William R; Adrada, Beatriz E; Santiago, Lumarie; Brennan, Patrick C

    2013-12-01

    Published information on contrast detection threshold is based primarily on research using a location-known methodology. In previous work on testing the Digital Imaging and Communications in Medicine (DICOM) Grayscale Standard Display Function (GSDF) for perceptual linearity, this research group used a location-unknown methodology to more closely reflect clinical practice. A high false-positive rate resulted in a high variance leading to the conclusion that the impact on results of employing a location-known methodology needed to be explored. Fourteen readers reviewed two sets of simulated mammographic background images, one with the location-unknown and one with the location-known methodology. The results of the reader study were analyzed using Reader Operating Characteristic (ROC) methodology and a paired t test. Contrast detection threshold was analyzed using contingency tables. No statistically significant difference was found in GSDF testing, but a highly statistical significant difference (p value <0.0001) was seen in the ROC (AUC) curve between the location-unknown and the location-known methodologies. Location-known methodology not only improved the power of the GSDF test but also affected the contrast detection threshold which changed from +3 when the location was unknown to +2 gray levels for the location-known images. The selection of location known versus unknown in experimental design must be carefully considered to ensure that the conclusions of the experiment reflect the study's objectives. PMID:23503988

  18. Modelling detection thresholds for sounds repeated at different delays.

    PubMed

    Heil, Peter; Verhey, Jesko L; Zoefel, Benedikt

    2013-02-01

    Detection thresholds for pairs or multiple copies of sounds are better than those for a single sound, an observation commonly interpreted as indicating temporal integration by the auditory system. Detection thresholds for pairs of brief tones depend on the delay between the tones (if short) and on frequency, suggesting frequency-dependent temporal overlap of auditory-filter responses elicited by the two successive stimuli (Krumbholz and Wiegrebe, 1998). The model presented by Krumbholz and Wiegrebe did not account for all aspects of their data, despite its complexity. This study shows that a simple probabilistic model based on Neubauer and Heil (2008) predicts the increase in threshold for short temporal delays as well as the asymptotic behaviour towards longer delays. The model entails (i) a 4th-order gammatone filter with a brief impulse response and thus broad bandwidth (shorter and broader than those of a filter normally assumed), (ii) the formation of stochastic 'spikes' or 'events' whose probability of occurrence is proportional to the filter output (half-wave rectified fine-structure or amplitude envelope), raised to a power of 3, and (iii) probability summation. The same model with the same front-end filter also predicts thresholds for pairs of clicks presented in band-reject noise, measured by Hall and Lummis (1973). The model accurately predicts the magnitudes and the decay of the alternating increase and decrease of thresholds as the delay between the click varies, the small effects of click polarity, and the dependence of thresholds for pairs of clicks with unequal intensities on their temporal order. Finally, we show that this model also correctly predicts the decrease in threshold with increasing number of temporally separated brief sounds, reported in several studies. While the latter data do not constrain the characteristics of the front-end filter, they do confirm the exponent of 3 in the model. Our paper stresses the viability of the model and raises the possibility that the bandwidths of filters estimated with psychophysical techniques may depend more strongly on the experimental paradigms and stimuli than hitherto thought. PMID:23268356

  19. Energy-momentum uncertainties as possible origin of threshold anomalies in UHECR and TeV-gamma ray events

    E-print Network

    Y. Jack Ng; D. -S. Lee; M. C. Oh; H. van Dam

    2000-10-24

    A threshold anomaly refers to a theoretically expected energy threshold that is not observed experimentally. Here we offer an explanation of the threshold anomalies encountered in the ultra-high energy cosmic ray events and the TeV-gamma ray events, by arguing that energy-momentum uncertainties due to quantum gravity, too small to be detected in low-energy regime, can affect particle kinematics so as to raise or even eliminate the energy thresholds. A possible modification of the energy-momentum dispersion relation, giving rise to time-of-flight differences between photons of different energies from gamma ray bursts, is also discussed.

  20. Threshold energy effect on avalanche breakdown voltage in semiconductor junctions

    Microsoft Academic Search

    Y. Okuto; C. R. Crowell

    1975-01-01

    The band bending for avalanche breakdown in semiconductor junctions and its temperature dependence are predicted taking account of threshold energy effects on the ionization process in semiconductors. Where experimental results exist, the theoretical predictions and experimental results are in excellent agreement. In the high electric field region inclusion of both bulk and boundary threshold energy effects is essential. The predictions

  1. Dynamic multiple thresholding breast boundary detection algorithm for mammograms

    SciTech Connect

    Wu, Yi-Ta; Zhou Chuan; Chan, Heang-Ping; Paramagul, Chintana; Hadjiiski, Lubomir M.; Daly, Caroline Plowden; Douglas, Julie A.; Zhang Yiheng; Sahiner, Berkman; Shi Jiazheng; Wei Jun [Department of Radiology, University of Michigan, Ann Arbor, Michigan 48109 (United States); Department of Human Genetics, University of Michigan, Ann Arbor, Michigan 48109 (United States); Department of Radiology, University of Michigan, Ann Arbor, Michigan 48109 (United States)

    2010-01-15

    Purpose: Automated detection of breast boundary is one of the fundamental steps for computer-aided analysis of mammograms. In this study, the authors developed a new dynamic multiple thresholding based breast boundary (MTBB) detection method for digitized mammograms. Methods: A large data set of 716 screen-film mammograms (442 CC view and 274 MLO view) obtained from consecutive cases of an Institutional Review Board approved project were used. An experienced breast radiologist manually traced the breast boundary on each digitized image using a graphical interface to provide a reference standard. The initial breast boundary (MTBB-Initial) was obtained by dynamically adapting the threshold to the gray level range in local regions of the breast periphery. The initial breast boundary was then refined by using gradient information from horizontal and vertical Sobel filtering to obtain the final breast boundary (MTBB-Final). The accuracy of the breast boundary detection algorithm was evaluated by comparison with the reference standard using three performance metrics: The Hausdorff distance (HDist), the average minimum Euclidean distance (AMinDist), and the area overlap measure (AOM). Results: In comparison with the authors' previously developed gradient-based breast boundary (GBB) algorithm, it was found that 68%, 85%, and 94% of images had HDist errors less than 6 pixels (4.8 mm) for GBB, MTBB-Initial, and MTBB-Final, respectively. 89%, 90%, and 96% of images had AMinDist errors less than 1.5 pixels (1.2 mm) for GBB, MTBB-Initial, and MTBB-Final, respectively. 96%, 98%, and 99% of images had AOM values larger than 0.9 for GBB, MTBB-Initial, and MTBB-Final, respectively. The improvement by the MTBB-Final method was statistically significant for all the evaluation measures by the Wilcoxon signed rank test (p<0.0001). Conclusions: The MTBB approach that combined dynamic multiple thresholding and gradient information provided better performance than the breast boundary detection algorithm that mainly used gradient information.

  2. Fuzzy entropy threshold approach to breast cancer detection

    Microsoft Academic Search

    H. D. Cheng

    1995-01-01

    Thresholding plays an important role in image processing. To select a suitable threshold requires some criteria on which to base the selection. A criterion of maximum fuzzy entropy is developed for selecting the threshold. In this algorithm, the degree of ambiguity in an image is measured by the entropy of a fuzzy set. The threshold is selected by maximizing the

  3. Threshold detection in an on-off binary communications channel with atmospheric scintillation

    NASA Technical Reports Server (NTRS)

    Webb, W. E.

    1975-01-01

    The optimum detection threshold in an on-off binary optical communications system operating in the presence of atmospheric turbulence was investigated assuming a poisson detection process and log normal scintillation. The dependence of the probability of bit error on log amplitude variance and received signal strength was analyzed and semi-empirical relationships to predict the optimum detection threshold derived. On the basis of this analysis a piecewise linear model for an adaptive threshold detection system is presented. The bit error probabilities for nonoptimum threshold detection systems were also investigated.

  4. Comparison of signal and gap-detection thresholds for focused and broad cochlear implant electrode configurations.

    PubMed

    Bierer, Julie Arenberg; Deeks, John M; Billig, Alexander J; Carlyon, Robert P

    2015-04-01

    Cochlear implant (CI) users usually exhibit marked across-electrode differences in detection thresholds with "focused" modes of stimulation, such as partial-tripolar (pTP) mode. This may reflect differences either in local neural survival or in the distance of the electrodes from the modiolus. To shed light on these two explanations, we compared stimulus-detection thresholds and gap-detection thresholds (GDTs) at comfortably loud levels for at least four electrodes in each of ten Advanced Bionics CI users, using 1031-pps pulse trains. The electrodes selected for each user had a wide range of stimulus-detection thresholds in pTP mode. We also measured across-electrode variations in both stimulus-detection and gap-detection tasks in monopolar (MP) mode. Both stimulus-detection and gap-detection thresholds correlated across modes. However, there was no significant correlation between stimulus-detection and gap-detection thresholds in either mode. Hence, gap-detection thresholds likely tap a source of across-electrode variation additional to, or different from, that revealed by stimulus-detection thresholds. Stimulus-detection thresholds were significantly lower for apical than for basal electrodes in both modes; this was only true for gap detection in pTP mode. Finally, although the across-electrode standard deviation in stimulus-detection thresholds was greater in pTP than in MP mode, the reliability of these differences--assessed by dividing the across-electrode standard deviation by the standard deviation across adaptive runs for each electrode--was similar for the two modes; this metric was also similar across modes for gap detection. Hence across-electrode differences can be revealed using clinically available MP stimulation, with a reliability comparable to that observed with focused stimulation. PMID:25644786

  5. Image boundaries detection: from thresholding to implicit curve evolution

    NASA Astrophysics Data System (ADS)

    Balla-Arabé, Souleymane; Brost, Vincent; Yang, Fan

    2015-02-01

    The development of high dimensional large-scale imaging devices increases the need of fast, robust and accurate image segmentation methods. Due to its intrinsic advantages such as the ability to extract complex boundaries, while handling topological changes automatically, the level set method (LSM) has been widely used in boundaries detection. Nevertheless, their computational complexity limits their use for real time systems. Furthermore, most of the LSMs share the limit of leading very often to a local minimum, while the effectiveness of many computer vision applications depends on the whole image boundaries. In this paper, using the image thresholding and the implicit curve evolution frameworks, we design a novel boundaries detection model which handles the above related drawbacks of the LSMs. In order to accelerate the method using the graphics processing units, we use the explicit and highly parallelizable lattice Boltzmann method to solve the level set equation. The introduced algorithm is fast and achieves global image segmentation in a spectacular manner. Experimental results on various kinds of images demonstrate the effectiveness and the efficiency of the proposed method.

  6. The role of stimulus complexity, spectral overlap, and pitch for gap-detection thresholds in young and old listeners.

    PubMed

    Heinrich, A; de la Rosa, S; Schneider, B A

    2014-10-01

    Thresholds for detecting a gap between two complex tones were determined for young listeners with normal hearing and old listeners with mild age-related hearing loss. The leading tonal marker was always a 20-ms, 250-Hz complex tone with energy at 250, 500, 750, and 1000?Hz. The lagging marker, also tonal, could differ from the leading marker with respect to fundamental frequency (f0), the presence versus absence of energy at f0, and the degree to which it overlapped spectrally with the leading marker. All stimuli were presented with steeper (1?ms) and less steep (4?ms) envelope rise and fall times. F0 differences, decreases in the degree of spectral overlap between the markers, and shallower envelope shape all contributed to increases in gap-detection thresholds. Age differences for gap detection of complex sounds were generally small and constant when gap-detection thresholds were measured on a log scale. When comparing the results for complex sounds to thresholds obtained for pure-tones in a previous study by Heinrich and Schneider [(2006). J. Acoust. Soc. Am. 119, 2316-2326], thresholds increased in an orderly fashion from markers with identical (within-channel) pure tones to different (between-channel) pure tones to complex sounds. This pattern of results was true for listeners of both ages although younger listeners had smaller thresholds overall. PMID:25324081

  7. The detection threshold, noise and stochastic resonance in the Fitzhugh-Nagumo neuron model

    NASA Astrophysics Data System (ADS)

    Pei, Xing; Bachmann, Ken; Moss, Frank

    1995-02-01

    In a class of experiments in sensory biology sub- or slightly supra-threshold stimuli are applied at the periphery while making action potential recordings at a higher level in the nervous system. In many cases the records are largely noise but with a small coherence with the stimulus. The detection threshold for increasing stimulus intensity is frequently measured, and this threshold can often be controlled by manipulating some additional biological parameter, for example, the temperature or inherent noise intensity. How does this parameter change the detection threshold? In this note, we test three popular paradigms on an electronic Fitzhugh-Nagumo neuron model and compare the results with a simple threshold theory.

  8. An Algorithm for 353 Odor Detection Thresholds in Humans

    PubMed Central

    Sánchez-Moreno, Ricardo; Cometto-Muñiz, J. Enrique; Cain, William S.

    2012-01-01

    One hundred and ninety three odor detection thresholds, ODTs, obtained by Nagata using the Japanese triangular bag method can be correlated as log (1/ODT) by a linear equation with R2 = 0.748 and a standard deviation, SD, of 0.830 log units; the latter may be compared with our estimate of 0.66 log units for the self-consistency of Nagata's data. Aldehydes, acids, unsaturated esters, and mercaptans were included in the equation through indicator variables that took into account the higher potency of these compounds. The ODTs obtained by Cometto-Muñiz and Cain, by Cometto-Muñiz and Abraham, and by Hellman and Small could be put on the same scale as those of Nagata to yield a linear equation for 353 ODTs with R2 = 0.759 and SD = 0.819 log units. The compound descriptors are available for several thousand compounds, and can be calculated from structure, so that further ODT values on the Nagata scale can be predicted for a host of volatile or semivolatile compounds. PMID:21976369

  9. Comparison of three methods for detection of the lactate threshold.

    PubMed

    Davis, James A; Rozenek, Ralph; DeCicco, Derek M; Carizzi, Michael T; Pham, Patrick H

    2007-11-01

    The lactate threshold (LT) represents the onset of a metabolic acidosis during graded exercise testing (GXT). It is a valuable measurement in clinical exercise testing and correlates well with endurance performance. Our purpose was to compare three LT detection methods, namely, Inspection (work rate at onset of a systematic increase in blood lactate concentration determined by inspection of blood lactate versus work rate plot), 0.5 mM (work rate which just precedes a rise in blood lactate concentration of >0.5 mM) and log-log (work rate at the intersection of two linear lines in plot of log lactate versus log work rate where the residual sum of squares for both lines added together is minimized). Fourteen subjects underwent cycle ergometer GXT with blood samples obtained at the end of each 3-min work rate increment and analysed for lactate concentration. The mean +/- 95% confidence limits of work rates at LT for the Inspection, 0.5 mM and log-log methods were 104.5 +/- 28.0, 103.2 +/- 28.1 and 105.1 +/- 27.3 W, respectively. Repeated-measures analysis of variance yielded a non-significant F ratio. The Bland-Altman bias +/- 95% limits of agreement for Inspection versus 0.5 mM, Inspection versus log-log and 0.5 mM versus log-log were 1.3 +/- 20.6, -0.6 +/- 12.5 and -1.9 +/- 20.5 W, respectively. The intraclass correlation coefficients for Inspection versus 0.5 mM, Inspection versus log-log and 0.5 mM versus log-log were 0.978, 0.992 and 0.977, respectively. The results of this study suggest that all three methods detect the LT at the same work rate. PMID:17944661

  10. A new EC-PC threshold estimation method for in vivo neural spike detection

    NASA Astrophysics Data System (ADS)

    Yang, Zhi; Liu, Wentai; Keshtkaran, Mohammad Reza; Zhou, Yin; Xu, Jian; Pikov, Victor; Guan, Cuntai; Lian, Yong

    2012-08-01

    This paper models in vivo neural signals and noise for extracellular spike detection. Although the recorded data approximately follow Gaussian distribution, they clearly deviate from white Gaussian noise due to neuronal synchronization and sparse distribution of spike energy. Our study predicts the coexistence of two components embedded in neural data dynamics, one in the exponential form (noise) and the other in the power form (neural spikes). The prediction of the two components has been confirmed in experiments of in vivo sequences recorded from the hippocampus, cortex surface, and spinal cord; both acute and long-term recordings; and sleep and awake states. These two components are further used as references for threshold estimation. Different from the conventional wisdom of setting a threshold at 3×RMS, the estimated threshold exhibits a significant variation. When our algorithm was tested on synthesized sequences with a different signal to noise ratio and on/off firing dynamics, inferred threshold statistics track the benchmarks well. We envision that this work may be applied to a wide range of experiments as a front-end data analysis tool.

  11. In vivo transcranial cavitation threshold detection during ultrasound-induced bloodbrain barrier opening in mice

    E-print Network

    Konofagou, Elisa E.

    In vivo transcranial cavitation threshold detection during ultrasound-induced blood­brain barrier cavitation threshold detection during ultrasound-induced blood­brain barrier opening in mice Yao-Sheng Tung1 cavitation response associated with blood­brain barrier (BBB) opening as induced by transcranial focused

  12. Efficient time series detection of the strong stochasticity threshold in Fermi-Pasta-Ulam oscillator lattices

    E-print Network

    M. Romero-Bastida; Alan Yoshio Reyes-Martinez

    2011-01-05

    In this work we study the possibility of detecting the so-called strong stochasticity threshold, i.e. the transition between weak and strong chaos as the energy density of the system is increased, in anharmonic oscillator chains by means of the 0-1 test for chaos. We compare the result of the aforementioned methodology with the scaling behavior of the largest Lyapunov exponent computed by means of tangent space dynamics, that has so far been the most reliable method available to detect the strong stochasticity threshold. We find that indeed the 0-1 test can perform the detection in the range of energy density values studied. Furthermore, we determined that conventional nonlinear time series analysis methods fail to properly compute the largest Lyapounov exponent even for very large data sets, whereas the computational effort of the 0-1 test remains the same in the whole range of values of the energy density considered with moderate size time series. Therefore, our results show that, for a qualitative probing of phase space, the 0-1 test can be an effective tool if its limitations are properly taken into account.

  13. Molecular dynamics simulation of threshold displacement energies in zircon

    SciTech Connect

    Moreira, Pedro A.; Devanathan, Ramaswami; Yu, Jianguo; Weber, William J.

    2009-10-15

    Molecular-dynamics simulations were used to examine the displacement threshold energy (Ed) surface for Zr, Si and O in zircon using two different interatomic potentials. For each sublattice, the simulation was repeated from different initial conditions to estimate the uncertainty in the calculated value of Ed. The displacement threshold energies vary considerably with crystallographic direction and sublattice. The average displacement energy calculated with a recently developed transferable potential is about 120 and 60 eV for cations and anions, respectively. The oxygen displacement energy shows good agreement with experimental estimates in ceramics.

  14. Energy threshold in multiple ionization by electron or positron impact

    NASA Astrophysics Data System (ADS)

    Montanari, C. C.; Miraglia, J. E.

    2015-01-01

    The energy threshold for the formation of highly charged ions is experimentally well-known and measured. For single ionization, it is the binding energy of the outermost electrons. For multiple ionization, the ionization begins at impact energies much larger than the theoretically expected ones. In this contribution we present a simple expression for the energy threshold for multiple ionization by electron or positron impact. It was obtained as the mean value of the energy transferred to each ionized electron by using Thompson classical approximation. Present results reproduce quite well the experimental thresholds. Moreover, the inclusion of these values in the theoretical multiple ionization cross sections allows describing rather well the experimental data for single up to sextuple ionization of rare gases.

  15. Threshold energy surface and Frenkel-pair resistivity for Cu

    SciTech Connect

    King, W.E.; Merkle, K.L.; Meshii, M.

    1982-01-01

    In-situ electrical resistivity damage-rate measurements in the high voltage electron microscope have been used to study electron-irradiation-induced defect production in copper single crystals at T < 10/sup 0/K. Analysis of the directional and energy dependence yields a threshold energy surface that is significantly different from those of previous investigations: two pockets of low threshold energy centered at <100> and <110> surrounded by regions of much higher threshold energy. The corresponding damage function exhibits a plateau of 0.6 Frenkel pairs. the present results imply a Frenkel pair resistivity for C of (2.75/sub -0.2//sup +0.6/) x ..cap omega..-cm.

  16. Re-examination of the threshold energy surface in copper

    SciTech Connect

    King, W.E.; Benedek, R.; Merkle, K.L.; Meshii, M.

    1981-01-01

    Radiation-induced defect production in copper has been studied using in-situ electrical resistivity damage-rate measurements in the HVEM and molecular dynamics simulations. Analysis of the results yields a threshold energy surface characterized by two isolated pockets of low threshold energy centered at <100> and <110> surrounded by regions of much higher threshold energy; the corresponding damage function exhibits a plateau at 0.65 Frenkel pairs. A Frenkel pair resistivity of (2.75/sub -0.2//sup +0/ /sup 6/) x 10/sup -4/ ..cap omega..-cm is proposed. A model damage function is constructed and compared to results from ion irradiation damage-rate measurements. 7 figures.

  17. Pooling optimal combinations of energy thresholds in spectroscopic CT

    NASA Astrophysics Data System (ADS)

    Koenig, Thomas; Zuber, Marcus; Hamann, Elias; Runz, Armin; Fiederle, Michael; Baumbach, Tilo

    2014-03-01

    Photon counting detectors used in spectroscopic CT are often based on small pixels and therefore offer only limited space to include energy discriminators and their associated counters in each pixel cell. For this reason, it is important to make efficient use of the available energy discriminators in order to achieve an optimized material contrast at a radiation dose as low as possible. Unfortunately, the complexity of evaluating every possible combination of energy thresholds, given a fixed number of counters, rapidly increases with the resolution at which this search is performed, and makes brute-force approaches to this problem infeasible. In this work, we introduce methods from machine learning, in particular sparse regression, to perform a feature selection to determine optimal combinations of energy thresholds. We will demonstrate how methods enforcing row-sparsity on a linear regression's coefficient matrix can be applied to the multiple response problem in spectroscopic CT, i.e. the case in which a single set of energy thresholds is sought to simultaneously retrieve concentrations pertaining to a multitude of materials in an optimal way. These methods are applied to CT images experimentally obtained with a Medipix3RX detector operated in charge summing mode and with a CdTe sensor at a pixel pitch of 110?m. We show that the least absolute shrinkage and selection operator (lasso), generalized to the multiple response case, chooses four out of 20 possible threshold positions that allow discriminating PMMA, iodine and gadolinium in a contrast agent phantom at a higher accuracy than with equally spaced thresholds. Finally, we illustrate why it might be unwise to use a higher number of energy thresholds than absolutely necessary.

  18. Empirical Learning Using Rule Threshold Optimization for Detection of Events in Synthetic Images

    Microsoft Academic Search

    David J. Montana

    1990-01-01

    We have developed an expert system for interpretation of passive sonar images. A key component of the system is a group of event detection rules whose conditions consist of tests against thresholds. Due to the complexity, variability and clumpiness (i.e., tendency towards highly nonuniform distribution) of the data, tuning these thresholds for good performance under all conditions is a difficult

  19. Kaon production at subthreshold and threshold energies

    E-print Network

    Jörg Aichelin; Christoph Hartnack

    2000-11-14

    We summarize what we have learnt about the kaon production in nucleus-nucleus collisions in the last decade. We will address three questions: a) Is the $K^+$ production sensitive to the nuclear equation of state? b) How can it happen that at the same excess energy the same number of $K^+$ and $K^-$ are produced in heavy ion collisions although the elementary cross section in pp collisions differs by orders of magnitudes? and c) Why kaons don't flow?

  20. Elevated visual motion detection thresholds in adults with acquired ophthalmoplegia

    Microsoft Academic Search

    J F Acheson; L Cassidy; E A Grunfeld; J A Shallo-Hoffman; A M Bronstein

    2001-01-01

    AIMSTo test the hypothesis that in patients with acquired chronic bilateral ophthalmoplegia, abnormal retinal image slippage during head movements would result in abnormal thresholds for visual perception of motion.METHODSFive patients (two males and three females) with ophthalmoplegia were included in the study. The average age was 44 years (range 30–69 years). The aetiology of ophthalmoplegia was myasthenia gravis (MG; n=2),

  1. Effect of Phonon Energy Loss on Photoemissive Yield near Threshold

    Microsoft Academic Search

    J. M. Ballantyne

    1972-01-01

    A phenomenological band-theoretic model for photoelectric emission which includes the effects of energy loss due to phonon scattering is developed. The model is applicable near threshold when the optical absorption depth is large compared to the phonon scattering length of hot electrons, and is particularly useful for cesiated surfaces with positive electron affinity. It is shown that in the low-photon-energy

  2. A Bispectral Composite Threshold Approach for Automatic Cloud Detection in VIIRS Imagery

    NASA Technical Reports Server (NTRS)

    LaFontaine Frank J.; Jedlovec, Gary J.

    2015-01-01

    The detection of clouds in satellite imagery has a number of important applications in weather and climate studies. The presence of clouds can alter the energy budget of the Earth-atmosphere system through scattering and absorption of shortwave radiation and the absorption and re-emission of infrared radiation at longer wavelengths. The scattering and absorption characteristics of clouds vary with the microphysical properties of clouds, hence the cloud type. Thus, detecting the presence of clouds over a region in satellite imagery is important in order to derive atmospheric or surface parameters that give insight into weather and climate processes. For many applications however, clouds are a contaminant whose presence interferes with retrieving atmosphere or surface information. In these cases, is important to isolate cloud-free pixels, used to retrieve atmospheric thermodynamic information or surface geophysical parameters, from cloudy ones. This abstract describes an application of a two-channel bispectral composite threshold (BCT) approach applied to VIIRS imagery. The simplified BCT approach uses only the 10.76 and 3.75 micrometer spectral channels from VIIRS in two spectral tests; a straight-forward infrared threshold test with the longwave channel and a shortwave - longwave channel difference test. The key to the success of this approach as demonstrated in past applications to GOES and MODIS data is the generation of temporally and spatially dependent thresholds used in the tests from a previous number of days at similar observations to the current data. The paper and subsequent presentation will present an overview of the approach and intercomparison results with other satellites, methods, and against verification data.

  3. Limitations in the spectral method for graph partitioning: Detectability threshold and localization of eigenvectors

    NASA Astrophysics Data System (ADS)

    Kawamoto, Tatsuro; Kabashima, Yoshiyuki

    2015-06-01

    Investigating the performance of different methods is a fundamental problem in graph partitioning. In this paper, we estimate the so-called detectability threshold for the spectral method with both un-normalized and normalized Laplacians in sparse graphs. The detectability threshold is the critical point at which the result of the spectral method is completely uncorrelated to the planted partition. We also analyze whether the localization of eigenvectors affects the partitioning performance in the detectable region. We use the replica method, which is often used in the field of spin-glass theory, and focus on the case of bisection. We show that the gap between the estimated threshold for the spectral method and the threshold obtained from Bayesian inference is considerable in sparse graphs, even without eigenvector localization. This gap closes in a dense limit.

  4. Predicting direction detection thresholds for arbitrary translational acceleration profiles in the horizontal plane

    PubMed Central

    Soyka, Florian; Robuffo Giordano, Paolo; Beykirch, Karl

    2011-01-01

    In previous research, direction detection thresholds have been measured and successfully modeled by exposing participants to sinusoidal acceleration profiles of different durations. In this paper, we present measurements that reveal differences in thresholds depending not only on the duration of the profile, but also on the actual time course of the acceleration. The measurements are further explained by a model based on a transfer function, which is able to predict direction detection thresholds for all types of acceleration profiles. In order to quantify a participant’s ability to detect the direction of motion in the horizontal plane, a four-alternative forced-choice task was implemented. Three types of acceleration profiles (sinusoidal, trapezoidal and triangular) were tested for three different durations (1.5, 2.36 and 5.86 s). To the best of our knowledge, this is the first study which varies both quantities (profile and duration) in a systematic way within a single experiment. The lowest thresholds were found for trapezoidal profiles and the highest for triangular profiles. Simulations for frequencies lower than the ones actually measured predict a change from this behavior: Sinusoidal profiles are predicted to yield the highest thresholds at low frequencies. This qualitative prediction is only possible with a model that is able to predict thresholds for different types of acceleration profiles. Our modeling approach represents an important advancement, because it allows for a more general and accurate description of perceptual thresholds for simple and complex translational motions. PMID:21234751

  5. The bifurcation threshold value of the chaos detection system for a weak signal

    NASA Astrophysics Data System (ADS)

    Li, Yue; Yang, Bao-Jun; Du, Li-Zhi; Yuan, Ye

    2003-07-01

    Recently, it has become an important problem to confirm the bifurcation threshold value of a chaos detection system for a weak signal in the fields of chaos detection. It is directly related to whether the results of chaos detection are correct or not. In this paper, the discrimination system for the dynamic behaviour of a chaos detection system for a weak signal is established by using the theory of linear differential equation with periodic coefficients and computing the Lyapunov exponents of the chaos detection system; and then, the movement state of the chaos detection system is defined. The simulation experiments show that this method can exactly confirm the bifurcation threshold value of the chaos detection system.

  6. A preliminary evaluation of a speed threshold incident detection algorithm 

    E-print Network

    Kolb, Stephanie Lang

    1996-01-01

    and California algorithm #8 using Fuzzy Logic to evaluate the new algorithm's effectiveness in detecting incidents on freeways. To test these algorithms, real data from TransGuide were run through the algorithms. Algorithm output were compared with CCTV (closed...

  7. Somatosensory evoked potentials associated with tactile stimulation at detection threshold in man.

    PubMed

    Soininen, K; Järvilehto, T

    1983-11-01

    Somatosensory evoked potentials elicited by sub- and supraliminal tactile pulses were studied during continuous threshold measurement. Two threshold methods were used: a modified tracking method and a detection method. With both methods threshold estimates of the same order of magnitude were obtained. Stimuli just above the threshold elicited a distinct somatosensory evoked potential with components P50, P100, N190 and P400. No such SEP was associated with the subliminal stimuli. However, in some cases some potential oscillations were obtained, time-locked to the subliminal stimuli; these are suggested to be due to errors in responding. In control experiments detected stimuli elicited a distinct SEP, but no SEP was associated with undetected stimuli of identical amplitude. The results indicate that in the psychophysical threshold determination the neural processing reflected in the SEP is associated only with supraliminal tactile stimulation. The lack of evoked brain activity associated with subliminal tactile stimuli supports the hypothesis derived from human microneurographic studies, stating that the tactile detection threshold may be based on an extremely small peripheral input, perhaps only on a single impulse in a single peripheral fiber. PMID:6194968

  8. Neuronal detection thresholds during vestibular compensation: contributions of response variability and sensory substitution

    PubMed Central

    Jamali, Mohsen; Mitchell, Diana E; Dale, Alexis; Carriot, Jerome; Sadeghi, Soroush G; Cullen, Kathleen E

    2014-01-01

    The vestibular system is responsible for processing self-motion, allowing normal subjects to discriminate the direction of rotational movements as slow as 1–2 deg s?1. After unilateral vestibular injury patients’ direction–discrimination thresholds worsen to ?20 deg s?1, and despite some improvement thresholds remain substantially elevated following compensation. To date, however, the underlying neural mechanisms of this recovery have not been addressed. Here, we recorded from first-order central neurons in the macaque monkey that provide vestibular information to higher brain areas for self-motion perception. Immediately following unilateral labyrinthectomy, neuronal detection thresholds increased by more than two-fold (from 14 to 30 deg s?1). While thresholds showed slight improvement by week 3 (25 deg s?1), they never recovered to control values – a trend mirroring the time course of perceptual thresholds in patients. We further discovered that changes in neuronal response variability paralleled changes in sensitivity for vestibular stimulation during compensation, thereby causing detection thresholds to remain elevated over time. However, we found that in a subset of neurons, the emergence of neck proprioceptive responses combined with residual vestibular modulation during head-on-body motion led to better neuronal detection thresholds. Taken together, our results emphasize that increases in response variability to vestibular inputs ultimately constrain neural thresholds and provide evidence that sensory substitution with extravestibular (i.e. proprioceptive) inputs at the first central stage of vestibular processing is a neural substrate for improvements in self-motion perception following vestibular loss. Thus, our results provide a neural correlate for the patient benefits provided by rehabilitative strategies that take advantage of the convergence of these multisensory cues. PMID:24366259

  9. Pressure Systems Stored-Energy Threshold Risk Analysis

    SciTech Connect

    Paulsen, Samuel S.

    2009-08-25

    Federal Regulation 10 CFR 851, which became effective February 2007, brought to light potential weaknesses regarding the Pressure Safety Program at the Pacific Northwest National Laboratory (PNNL). The definition of a pressure system in 10 CFR 851 does not contain a limit based upon pressure or any other criteria. Therefore, the need for a method to determine an appropriate risk-based hazard level for pressure safety was identified. The Laboratory has historically used a stored energy of 1000 lbf-ft to define a pressure hazard; however, an analytical basis for this value had not been documented. This document establishes the technical basis by evaluating the use of stored energy as an appropriate criterion to establish a pressure hazard, exploring a suitable risk threshold for pressure hazards, and reviewing the methods used to determine stored energy. The literature review and technical analysis concludes the use of stored energy as a method for determining a potential risk, the 1000 lbf-ft threshold, and the methods used by PNNL to calculate stored energy are all appropriate. Recommendations for further program improvements are also discussed

  10. Thresholding for biological material detection in real-time multispectral imaging

    NASA Astrophysics Data System (ADS)

    Yoon, Seung Chul; Park, Bosoon; Lawrence, Kurt C.; Windham, William R.

    2005-09-01

    Recently, hyperspectral image analysis has proved successful for a target detection problem encountered in remote sensing as well as near sensing utilizing in situ instrumentation. The conventional global bi-level thresholding for target detection, such as the clustering-based Otsu's method, has been inadequate for the detection of biologically harmful material on foods that has a large degree of variability in size, location, color, shape, texture, and occurrence time. This paper presents multistep-like thresholding based on kernel density estimation for the real-time detection of harmful contaminants on a food product presented in multispectral images. We are particularly concerned with the detection of fecal contaminants on poultry carcasses in real-time. In the past, we identified 2 optimal wavelength bands and developed a real-time multispectral imaging system using a common aperture camera and a globally optimized thresholding method from a ratio of the optimal bands. This work extends our previous study by introducing a new decision rule to detect fecal contaminants on a single bird level. The underlying idea is to search for statistical separability along the two directions defined by the global optimal threshold vector and its orthogonal vector. Experimental results with real birds and fecal samples in different amounts are provided.

  11. Effects of sodium depletion on detection thresholds for salty taste in rats.

    PubMed

    Lu, Bo; Yan, Jianqun; Yang, Xuejuan

    2009-06-22

    Previous studies, which have mostly focused on concentrated NaCl solution intake, have suggested sodium depletion may be accompanied with salt taste sensory changes. To further investigate whether the function of the salt taste system changes in different patterns for highly concentrated and diluted NaCl taste stimuli, the effects of sodium depletion on NaCl taste detection threshold in rats were examined. After a conditioned taste aversion (CTA) to a suprathreshold concentration of NaCl (0.1 M) was established, rats were given a series of two-bottle choice tests between distilled water and different concentrations of NaCl. Conditioned rats will generalize the aversion to diluted solutions when they are detected. The taste detection threshold for NaCl is defined as the lowest concentration at which there is a reliable difference in the preference scores between conditioned and control subjects. The results showed that detection threshold for NaCl lay between 0.003 M and 0.005 M in sodium-replete rats, whereas in sodium-depleted rats that have an amplified action of angiotensin II in the brain, the threshold significantly decreased to be between 0.0001 M and 0.0003 M. However, in rats with a blocked action of angiotensin II in the brain the decreased NaCl detection threshold was between 0.001 M and 0.003 M. These findings suggest that sodium-depleted rats could decrease the NaCl taste detection threshold to increase the ability to find sodium ions. And the regulation of the salt taste sensitivity may be related to the action of angiotensin II in brain. PMID:19341747

  12. A preliminary evaluation of a speed threshold incident detection algorithm

    E-print Network

    Kolb, Stephanie Lang

    1996-01-01

    the probabiTity that an incident occurred. The ~ applies the relative spatial difFerence in occupancies (OCCRDF) feature which was previously de6ned for the California algorithms. This parameter was selected because its values are typically stable, yet...-layer feed-forward neural network to detect incidents (17j. In a feed-forward neural network, the results from one neuron are only input to a layer following the current layer. This type of non-linear neural network is de6ned as supervised, comparing...

  13. Orientation tuning in human colour vision at detection threshold

    PubMed Central

    Gheiratmand, Mina; Mullen, Kathy T.

    2014-01-01

    We measure the orientation tuning of red-green colour and luminance vision at low (0.375?c/deg) and mid (1.5?c/deg) spatial frequencies using the low-contrast psychophysical method of subthreshold summation. Orientation bandwidths of the underlying neural detectors are found using a model involving Minkowski summation of the rectified outputs of a bank of oriented filters. At 1.5?c/deg, we find orientation-tuned detectors with similar bandwidths for chromatic and achromatic contrast. At 0.375?c/deg, orientation tuning is preserved with no change in bandwidth for achromatic stimuli, however, for chromatic stimuli orientation tuning becomes extremely broad, compatible with detection by non-oriented colour detectors. A non-oriented colour detector, previously reported in single cells in primate V1 but not psychophysically in humans, can transmit crucial information about the color of larger areas or surfaces whereas orientation-tuned detectors are required to detect the colour or luminance edges that delineate an object's shape. PMID:24594749

  14. Reduced Complexity Detection for Ricean MIMO Channels Based on Condition Number Thresholding

    E-print Network

    Wang, Cheng-Xiang

    Reduced Complexity Detection for Ricean MIMO Channels Based on Condition Number Thresholding transmit and receive antenna elements is presented. Our prime aim is to reduce the extensive complexity of the adaptive detector (AD) is a hard- decision criterion based on the condition number of the MIMO correlation

  15. Adaptive threshold-based fault detection and isolation for automotive electrical systems

    Microsoft Academic Search

    Ali Hashemi; Pierluigi Pisu

    2011-01-01

    In this paper, a fault diagnosis scheme to detect and isolate faults commonly occurring in a vehicle alternator system based on an adaptive thresholds approach is developed. The mathematical model of the alternator subsystem is quite involved and highly nonlinear; to simplify the diagnostic scheme, an equivalent linear time varying model based on the input- output behavior of the system

  16. Detecting and Measuring Fine Roots in Minirhizotron Images Using Matched Filtering and Local Entropy Thresholding

    Microsoft Academic Search

    Guang Zeng; Stanley T. Birchfield; Christina E. Wells

    2006-01-01

    An approach to automate the extraction and measurement of roots in minirhizotron images is presented. Two-dimensional matched filtering is followed by local entropy thresholding to produce binarized images from which roots are detected. After applying a root classifier to discriminate fine roots from unwanted background objects, a root labeling method is implemented to identify each root in the image. Once

  17. Olfactory Detection Thresholds and Adaptation in Adults with Autism Spectrum Condition

    ERIC Educational Resources Information Center

    Tavassoli, T.; Baron-Cohen, S.

    2012-01-01

    Sensory issues have been widely reported in Autism Spectrum Conditions (ASC). Since olfaction is one of the least investigated senses in ASC, the current studies explore olfactory detection thresholds and adaptation to olfactory stimuli in adults with ASC. 80 participants took part, 38 (18 females, 20 males) with ASC and 42 control participants…

  18. Electrical microstimulation thresholds for behavioral detection and saccades in monkey frontal eye fields

    E-print Network

    Crawford, Doug

    Electrical microstimulation thresholds for behavioral detection and saccades in monkey frontal eye into saccadic eye movements. Although it is often considered an oculomotor structure, several lines of evidence by electrical microstimulation with currents below those that cause eye movements. We found that stimulation

  19. Detection of oil slick signatures in SAR images by fusion of hysteresis thresholding responses

    Microsoft Academic Search

    Thomas. F. n. Kanaa; E. Tonye; G. Mercier; V. P. Onana; J. Mvogo Ngono; P. L. Frison; J. P. Rudant; R. Garello

    2003-01-01

    A new method is proposed in this paper to detect oil slick signatures in oceanographic SAR images. This method is based on directional behavioural oil slick in the sea surface. Therefore, directional hysteresis thresholding responses are first computed in order to bring to the fore dark spots, and increase pixels connexity in each Freeman direction. Those responses are then merged

  20. STATISTICAL MODEL-BASED THRESHOLDING OF MULTISPECTRAL IMAGES FOR CONTAMINANT DETECTION ON POULTRY CARCASSES

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Developing an algorithm to decide the presence or absence of fecal contamination on the surface of poultry carcasses is critical to food safety. The global threshold strategy for a band-ratio algorithm has been known to be limited to pixel-basis detection. In an attempt to develop a statistical deci...

  1. Threshold detection performance of GMSK signal with BT=0.5

    Microsoft Academic Search

    Gee L. Lui

    1998-01-01

    This paper considers the detection performance of a serial thresholding receiver for precoded binary GMSK signal with BT=0.5. The conditional symbol (bit) error probability of the GMSK signal with carrier phase and timing errors is derived and compared to that of unfiltered BPSK. It is shown that the GMSK signal has practically the same performance as the ideal BPSK signal

  2. Haptic detection thresholds of Gaussian profiles over the whole range of spatial scales.

    PubMed

    Louw, S; Kappers, A M; Koenderink, J J

    2000-06-01

    In the literature only a small subset of the broad range of scales of human haptic perception has been explored. In this experiment, haptic detection thresholds have been investigated over a wide range of spatial scales. Computer-controlled manufacturing techniques have made it possible to produce stimuli with sufficient accuracy to explore the gamut of haptic scales. We used stimuli with a convex or concave Gaussian-shaped profile running over the middle of a strip. The width of the Gaussian profile was varied between 150 microns and 240 mm. In this range of spatial scales a number of mechanisms, ranging from cutaneous mechanoreception to proprioception in fingers, arm and shoulder, contribute to haptic perception. The discrimination threshold between a flat surface and a Gaussian surface was investigated in a series of two alternative forced choice experiments on human subjects. The thresholds run from 1 micron for the narrowest Gaussian profiles to 8 mm for the broadest profile. The same thresholds were found for convex and concave shapes. Over the range of spatial scales, from 1 mm width on, the dependence of the detection threshold on the spatial width of the Gaussian profile was found to be a power function with an exponent of about 1.3. PMID:10883385

  3. Origin of the Low Energy Structure in Above Threshold Ionization

    E-print Network

    Titi, Atef S

    2015-01-01

    We present an ab initio analytic theory to account for both the very low energy structure (VLES) [C. Y. Wu et al., Phys. Rev. Lett. 109, 043001 (2012); W. Quan et al., Phys. Rev. Lett. 103, 093001 (2009)], and the low energy structure (LES) [W. Quan et al. Phys. Rev. Lett. 103, 093001 (2009); C.I. Blaga et al., Nat. Phys. 5, 335 2009)] of above threshold ionization. The origin of both VLES and LES lies in a forward scattering mechanism by the Coulomb potential. We parameterize the S matrix in terms of ?, which is the displacement of the the classical motion of an electron in the laser field. When ? = 0, the S matrix is singular, which we attribute to be forward Coulomb scattering without absorption of light quanta. By devising a regularization scheme, the resulting S matrix is non-singular when ? = 0, and the origins of VLES and LES are revealed. We attribute VLES to multiple forward scattering of near-threshold electrons by the Coulomb potential, with no absorption of light quanta, signifying the role of the...

  4. Odor detection thresholds of naphthenic acids from commercial sources and oil sands process-affected water.

    PubMed

    Edge, Kristyn; Barona, Brenda; Young, Rozlyn F; Fedorak, Phillip M; Wismer, Wendy V

    2010-11-01

    Naphthenic acids (NAs) occur naturally in various petroleums and in oil sands tailings waters and have been implicated as potential fish tainting compounds. In this study, trained sensory panels and the general population from a university were used to determine the odor detection thresholds of two commercial NAs preparations (Acros and Merichem) and of NAs extracted from an oil sands experimental reclamation pond (Pond 9). Using the three-alternative forced choice method, a concentration series of NAs were presented to the sensory panels in phosphate buffer (pH 8) and in steamed fish (Sander vitreus). In buffer, the odor detection thresholds of Acros, Merichem and Pond 9 NAs, as evaluated by the trained panelists, were 1.5, 0.04, and 1.0 mg L(-1), respectively. Only the detection threshold for the Merichem NAs was significantly different (p<0.01) than the other two sources. Based on the general population assessments, all three odor detection thresholds were significantly different from one another; 4.8, 0.2, and 2.5 mg L(-1) for Acros, Merichem, and Pond 9 NAs, respectively (p<0.01). The odor detection thresholds of Merichem and Pond 9 NAs in steamed fish were 0.6 and 12 mg kg(-1), respectively and were significantly different from each other (p<0.01). The detection threshold of Acros NAs was estimated to be >21 mg kg(-1). For the steamed fish evaluations, the odor descriptors of all three of the NAs preparations was given as chemical in nature (Acros: oil, plastic; Merichem: gasoline; Pond 9: gasoline, tar). Exposure of live rainbow trout to a non-lethal concentration of Merichem NAs (3 mg L(-1) for 10 d) imparted an odor to the fish flesh. Analyses of the three NAs preparations by gas chromatography-mass spectrometry showed that each had a unique distribution of acids. We conclude that the source of the NAs is important when interpreting odor threshold data and that the two commercial preparations of NAs that were tested do not represent oil sands waters' tainting potential. PMID:20801486

  5. Computer-aided mass detection on digitized mammograms using adaptive thresholding and fuzzy entropy.

    PubMed

    Younesi, F; Alam, N; Zoroofi, R A; Ahmadian, A; Guiti, M

    2007-01-01

    In this paper, a segmentation method for detection of masses in digitized mammograms has been developed using two parallel approaches: adaptive thresholding method and fuzzy entropy feature as a CAD scheme. The algorithm consists of the following steps: a) Preprocessing of the digitized mammograms including identification of region of interest (ROI) as candidate for massive lesion through breast region extraction, b) Image enhancement using linear transformation and subtracting enhanced from the original image, c) Characterization of the ROI by extracting the fuzzy entropy feature, d) Local adaptive thresholding for segmentation of mass areas, e) Combine expert of the last two parallel approaches for mass detection. The proposed method was tested on 78 mammograms (30 normal & 48 cancerous) from the BIRADS and local databases. The detected regions validated by comparing them with the radiologists' hand-sketched boundaries of real masses. The current algorithm can achieve a sensitivity of 90.73% and specificity of 89.17%. This approach showed that the behavior of local adaptive thresholding and fuzzy entropy technique could be a useful method for mass detection on digitized mammograms. Our results suggest that the proposed method could help radiologists as a second reader in mammographic screening of masses. PMID:18003291

  6. Cooperative Spectrum Sensing with Multiple Antennas Using Adaptive Double-Threshold Based Energy Detector in Cognitive Radio Networks

    NASA Astrophysics Data System (ADS)

    Bagwari, A.; Tomar, G. S.

    2014-04-01

    In Cognitive radio networks, spectrum sensing is used to sense the unused spectrum in an opportunistic manner. In this paper, multiple antennas based energy detector utilizing adaptive double-threshold for spectrum sensing is proposed, which enhances detection performance and overcomes sensing failure problem as well. The detection threshold is made adaptive to the fluctuation of the received signal power in each local detector of cognitive radio (CR) user. Numerical results show that by using multiple antennas at the CRs, it is possible to significantly improve detection performance at very low signal-to-noise ratio (SNR). Further, the scheme was analyzed in conjunction with cooperative spectrum sensing (CSS), where CRs utilize selection combining of the decision statistics obtained by an adaptive double-threshold energy detector for making a binary decision of the presence or absence of a primary user. The decision of each CR is forwarded over error free orthogonal channels to the fusion centre, which takes the final decision of a spectrum hole. It is further found that CSS with multiple antenna-based energy detector with adaptive double-threshold improves detection performance around 26.8 % as compared to hierarchical with quantization method at -12 dB SNR, under the condition that a small number of sensing nodes are used in spectrum sensing.

  7. Reduced visual surround suppression in schizophrenia shown by measuring contrast detection thresholds

    PubMed Central

    Serrano-Pedraza, Ignacio; Romero-Ferreiro, Verónica; Read, Jenny C. A.; Diéguez-Risco, Teresa; Bagney, Alexandra; Caballero-González, Montserrat; Rodríguez-Torresano, Javier; Rodriguez-Jimenez, Roberto

    2014-01-01

    Visual perception in schizophrenia is attracting a broad interest given the deep knowledge that we have about the visual system in healthy populations. One example is the class of effects known collectively as visual surround suppression. For example, the visibility of a grating located in the visual periphery is impaired by the presence of a surrounding grating of the same spatial frequency and orientation. Previous studies have suggested abnormal visual surround suppression in patients with schizophrenia. Given that schizophrenia patients have cortical alterations including hypofunction of NMDA receptors and reduced concentration of GABA neurotransmitter, which affect lateral inhibitory connections, then they should be relatively better than controls at detecting visual stimuli that are usually suppressed. We tested this hypothesis by measuring contrast detection thresholds using a new stimulus configuration. We tested two groups: 21 schizophrenia patients and 24 healthy subjects. Thresholds were obtained using Bayesian staircases in a four-alternative forced-choice detection task where the target was a grating within a 3? Butterworth window that appeared in one of four possible positions at 5? eccentricity. We compared three conditions, (a) target with no-surround, (b) target embedded within a surrounding grating of 20? diameter and 25% contrast with same spatial frequency and orthogonal orientation, and (c) target embedded within a surrounding grating with parallel (same) orientation. Previous results with healthy populations have shown that contrast thresholds are lower for orthogonal and no-surround (NS) conditions than for parallel surround (PS). The log-ratios between parallel and NS thresholds are used as an index quantifying visual surround suppression. Patients performed poorly compared to controls in the NS and orthogonal-surround conditions. However, they performed as well as controls when the surround was parallel, resulting in significantly lower suppression indices in patients. To examine whether the difference in suppression was driven by the lower NS thresholds for controls, we examined a matched subgroup of controls and patients, selected to have similar thresholds in the NS condition. Patients performed significantly better in the PS condition than controls. This analysis therefore indicates that a PS raised contrast thresholds less in patients than in controls. Our results support the hypothesis that inhibitory connections in early visual cortex are impaired in schizophrenia patients. PMID:25540631

  8. Bubbles detection for inter-war European hyperinflation: A threshold cointegration approach

    Microsoft Academic Search

    Hing Lin Chan; Kai Yin Woo

    2006-01-01

    This paper undertakes an empirical investigation into the existence of inflationary bubbles during the inter-war European\\u000a hyperinflation for Germany, Hungary, Poland and Russia. Our Monte Carlo simulations show that the residual-based threshold\\u000a cointegration methodology of Caner and Hansen (2001) is better able to detect periodically collapsing bubbles. Moreover, this\\u000a methodology possesses greater power against nonlinear stationary alternatives in a finite

  9. Probability density function and detection threshold in high contrast imaging with partially polarized light

    E-print Network

    Yaitskova, Natalia

    2009-01-01

    We obtain an expression for the probability density function (PDF) of partially developed speckles formed by light with an arbitrary degree of polarization. From the probability density we calculate the detection threshold corresponding to the 5sigma confidence level of a normal distribution. We show that unpolarized light has an advantage in high contrast imaging for low ratios of the deterministic part of the point spread function (DL PSF) to the halo, typical in coronagraphy.

  10. A threshold-based fall-detection algorithm using a bi-axial gyroscope sensor

    Microsoft Academic Search

    A. K. Bourke; G. M. Lyons

    2008-01-01

    A threshold-based algorithm, to distinguish between Activities of Daily Living (ADL) and falls is described. A gyroscope based fall-detection sensor array is used. Using simulated-falls performed by young volunteers under supervised conditions onto crash mats and ADL performed by elderly subjects, the ability to discriminate between falls and ADL was achieved using a bi-axial gyroscope sensor mounted on the trunk,

  11. Automated microcalcification detection in mammograms using statistical variable-box-threshold filter method

    NASA Astrophysics Data System (ADS)

    Wilson, Mark; Mitra, Sunanda; Roberson, Glenn H.; Shieh, Yao-Yang

    1997-10-01

    Currently early detection of breast cancer is primarily accomplished by mammography and suspicious findings may lead to a decision for performing a biopsy. Digital enhancement and pattern recognition techniques may aid in early detection of some patterns such as microcalcification clusters indicating onset of DCIS (ductal carcinoma in situ) that accounts for 20% of all mammographically detected breast cancers and could be treated when detected early. These individual calcifications are hard to detect due to size and shape variability and inhomogeneous background texture. Our study addresses only early detection of microcalcifications that allows the radiologist to interpret the x-ray findings in computer-aided enhanced form easier than evaluating the x-ray film directly. We present an algorithm which locates microcalcifications based on local grayscale variability and of tissue structures and image statistics. Threshold filters with lower and upper bounds computed from the image statistics of the entire image and selected subimages were designed to enhance the entire image. This enhanced image was used as the initial image for identifying the micro-calcifications based on the variable box threshold filters at different resolutions. The test images came from the Texas Tech University Health Sciences Center and the MIAS mammographic database, which are classified into various categories including microcalcifications. Classification of other types of abnormalities in mammograms based on their characteristic features is addressed in later studies.

  12. Thresholds of Passive Microwave Snowfall Detection Determined Using A-Train Observations

    NASA Astrophysics Data System (ADS)

    Munchak, S. J.; Skofronick Jackson, G.; Johnson, B. T.

    2011-12-01

    In this study we explore a database of CloudSat+AMSU-B coincident overpasses to determine the minimum threshold of passive microwave detection of snowfall using the high-frequency channels available on GMI. Using the Advanced Infrared Sounder (AIRS) temperature and water vapor profiles along with a surface emissivity database developed from AMSU-B and MHS observations, clear-sky radiances are simulated and compared to AMSU-B observed radiances for all profiles with a maximum temperature less than 271 K. The ability of a scattering signal (observed brightness tempertaure colder than clear-sky brightness temperature by a threshold T) to detect snowfall (CloudSat reflectivity greater than threshold Z) is quantified using the Heidke Skill Score. The 183+/-1 and 183+/-3 GHz channels have the highest skill scores, while those channels that are sensitive to the surface (89, 150 and 183+/-7 GHz) have zero or even negative skill (depending on Z and T), implying that an emission signal (presumably from cloud water) is as good or better for detecting precipitation than a scattering signal. These results emphasize the need for proper characterization of surface emissivity and adequate representation of cloud water in cold season precipitation profiles that form the databases used for Bayesian retrievals from GMI and other GPM constellation radiometers.

  13. Segmental Impedance Thresholds for Early Detection of Unilateral Upper Limb Swelling.

    PubMed

    Svensson, B J; Dylke, E S; Ward, L C; Kilbreath, S L

    2014-05-16

    Abstract Background: Detection of early lymphedema is important for effective treatment outcome and reduction of disease burden. The aims of this study were to determine normal inter-limb variance in the hand and four segments of the arm using bioimpedance spectroscopy (BIS) to provide diagnostic thresholds for detection of early lymphedema development, to determine the intra-rater reliability of these measurements, and to compare the inter-limb BIS ratios to differences based on arm circumference measures. Methods and results: One hundred women, aged 49.1 (SD 13.8) years without history of breast cancer or lymphedema participated. Impedance measures for the hand and four 10?cm length arm segments were used to determine the inter-limb segment BIS ratios. Circumference difference and segment volumes were calculated from circumference measures obtained with a tape measure. A subgroup of women was measured on two occasions, one week apart. Thresholds were determined for the dominant and nondominant limb, based on two and three standard deviations (SD) above the mean. The 2SD and 3SD thresholds for the dominant arm ranged from 1.121 to 1.150 and 1.172 to 1.209, respectively, and for the nondominant limb ranged from 1.057 to 1.107 and 1.103 to 1.169, respectively. Intra-rater reliability was high (ICC: 0.945-0.983). BIS ratio and circumference-based measures did not identify the same segments as being over threshold. Conclusions: BIS diagnostic thresholds for the hand and four segments of the arm, based on normative data, taking into consideration arm dominance have been developed. Segmental BIS has been shown to be highly reliable. PMID:24837521

  14. Detection and recognition threshold values of odorants used in the odorization of natural gas

    SciTech Connect

    Moschundreas, D.J.; Jones, D.; Martinus, J.

    1982-06-01

    This study was designed to determine if odorization practices provide adequate warning for detecting and reacting to gas leakage and involves direct sensory measurements under totally controlled conditions with experienced panelists, indirect measurements by randomly selected panelists exposed to varying odorant levels inside a specially built chamber, and other-directed measurements that test the of the other measurements. This paper reports the findings of the direct sensory measurements and also measurements of odor detection and recognition threshold values, dose-response curves and an assessment of the capabilities of currently used odorants to serve as warning agents.

  15. Fine-Grained Emotion Detection in Suicide Notes: A Thresholding Approach to Multi-Label Classification

    PubMed Central

    Luyckx, Kim; Vaassen, Frederik; Peersman, Claudia; Daelemans, Walter

    2012-01-01

    We present a system to automatically identify emotion-carrying sentences in suicide notes and to detect the specific fine-grained emotion conveyed. With this system, we competed in Track 2 of the 2011 Medical NLP Challenge,14 where the task was to distinguish between fifteen emotion labels, from guilt, sorrow, and hopelessness to hopefulness and happiness. Since a sentence can be annotated with multiple emotions, we designed a thresholding approach that enables assigning multiple labels to a single instance. We rely on the probability estimates returned by an SVM classifier and experimentally set thresholds on these probabilities. Emotion labels are assigned only if their probability exceeds a certain threshold and if the probability of the sentence being emotion-free is low enough. We show the advantages of this thresholding approach by comparing it to a naïve system that assigns only the most probable label to each test sentence, and to a system trained on emotion-carrying sentences only. PMID:22879761

  16. Application of new advanced CNN structure with adaptive thresholds to color edge detection

    NASA Astrophysics Data System (ADS)

    Deng, Shaojiang; Tian, Yuan; Hu, Xipeng; Wei, Pengcheng; Qin, Mingfu

    2012-04-01

    Color edge detection is much more efficient than gray scale detection when edges exist at the boundary between regions of different colors with no change in intensity. This paper presents adaptive templates, which are capable of detecting various color and intensity changes in color image. To avoid conception of multilayer proposed in literatures, modification has been done to the CNN structure. This modified structure allows a matrix C, which carries the change information of pixels, to replace the control parts in the basic CNN equation. This modification is necessary because in multilayer structure, it faces the challenge of how to represent the intrinsic relationship among each primary layer. Additionally, in order to enhance the accuracy of edge detection, adaptive detection threshold is employed. The adaptive thresholds are considered to be alterable criteria in designing matrix C. The proposed synthetic system not only avoids the problem which is engendered by multi-layers but also exploits full information of pixels themselves. Experimental results prove that the proposed method is efficient.

  17. Detectability thresholds and optimal algorithms for community structure in dynamic networks

    E-print Network

    Ghasemian, Amir; Clauset, Aaron; Moore, Cristopher; Peel, Leto

    2015-01-01

    We study the fundamental limits on learning latent community structure in dynamic networks. Specifically, we study dynamic stochastic block models where nodes change their community membership over time, but where edges are generated independently at each time step. In this setting (which is a special case of several existing models), we are able to derive the detectability threshold exactly, as a function of the rate of change and the strength of the communities. Below this threshold, we claim that no algorithm can identify the communities better than chance. We then give two algorithms that are optimal in the sense that they succeed all the way down to this limit. The first uses belief propagation (BP), which gives asymptotically optimal accuracy, and the second is a fast spectral clustering algorithm, based on linearizing the BP equations. We verify our analytic and algorithmic results via numerical simulation, and close with a brief discussion of extensions and open questions.

  18. Data rate maximization by adaptive thresholding RF power management under renewable energy

    Microsoft Academic Search

    Weiguo Tang; Lei Wang

    2010-01-01

    A new adaptive thresholding power management (ATPM) scheme is proposed to maximize the data rate of RF circuits in distributed embedded systems powered by renewable energy. Considering time-varying fading channels and statistical energy harvesting processes, we propose to turn on RF circuits only when the channel gain is higher than a threshold, and adjust the RF power according to the

  19. Saltation threshold detection in a wind tunnel by the measurement of the net electrostatic charge

    NASA Technical Reports Server (NTRS)

    Leach, Rodman N.

    1991-01-01

    The Mars surface wind tunnel (MARSWIT) is an open circuit wind tunnel used for aeolian studies and is located inside a large vacuum chamber allowing testing at Martian surface atmospheric pressure. Since direct access is not available to the tunnel during operation at low pressure, a remote method of saltation detection is needed. The bed is observed by means of closed circuit video, but it is often difficult to determine the initiation of threshold. The measurement by means of an electrometer of the net electric charge produced by the saltating particles has provided a reliable means of saltation threshold detection. Saltating particles become charged several ways, both in wind tunnels and in a natural environment. The most significant of these methods are tribo-charging and contact charging, which always occur. Fracture charging may also occur under the high velocities associated with particle transport on Mars or under simulated Martian conditions. Detection in MARSWIT is achieved by allowing the saltating particles to impinge on a planar conducting surface normal to the flow that is connected to ground through a Keithly electrometer. The signal from the electrometer is connected to a strip chart recorder along with the analog signal from the pitot tube transducer that is used to determine the wind velocity in the tunnel. Thus, a record of wind velocity and the initiation of particle saltation is conveniently displayed together. While both positive and negative charges are produced during saltation, this method measures only the net charge; thus the charge may be either positive or negative depending upon the particles being tested, the size and size distribution of the test material, and the wind velocity. This has proven to be a very trustworthy and sensitive method of saltation threshold detection, being especially useful with the smaller sized particles which are the most difficult to observe visually.

  20. The transfer function of a target limits the jitter detection threshold with signals of echolocating FM-bats

    Microsoft Academic Search

    Kristian Beedholm

    2006-01-01

    The delay jitter discrimination threshold in bats is a disputed subject. Some investigators have obtained results indicating\\u000a that bats are able to discriminate alternations in delay down to 10 ns, which appears incredible for purely physical reasons.\\u000a Using actual bat echolocation sequences recorded during an easy detection task to measure simulated delay jitter, it is shown\\u000a here that jitter detection thresholds

  1. Design and Synthesis of Ultralow Energy Spin-Memristor Threshold Logic

    NASA Astrophysics Data System (ADS)

    Fan, Deliang; Sharad, Mrigank; Roy, Kaushik

    2014-05-01

    A threshold logic gate (TLG) performs weighted sum of multiple inputs and compares the sum with a threshold. We propose Spin-Memeristor Threshold Logic (SMTL) gates, which employ memristive cross-bar array (MCA) to perform current-mode summation of binary inputs, whereas, the low-voltage fast-switching spintronic threshold devices (STD) carry out the threshold operation in an energy efficient manner. Field programmable SMTL gate arrays can operate at a small terminal voltage of ~50mV, resulting in ultra-low power consumption in gates as well as programmable interconnect networks. We evaluate the performance of SMTL using threshold logic synthesis. Results for common benchmarks show that SMTL based programmable logic hardware can be more than 100x energy efficient than state of the art CMOS FPGA.

  2. Detection of Near-Threshold Sounds is Independent of EEG Phase in Common Frequency Bands

    PubMed Central

    Zoefel, Benedikt; Heil, Peter

    2013-01-01

    Low-frequency oscillations in the electroencephalogram (EEG) are thought to reflect periodic excitability changes of large neural networks. Consistent with this notion, detection probability of near-threshold somatosensory, visual, and auditory targets has been reported to co-vary with the phase of oscillations in the EEG. In audition, entrainment of ?-oscillations to the periodic occurrence of sounds has been suggested to function as a mechanism of attentional selection. Here, we examine in humans whether the detection of brief near-threshold sounds in quiet depends on the phase of EEG oscillations. When stimuli were presented at irregular intervals, we did not find a systematic relationship between detection probability and phase. When stimuli were presented at regular intervals (2-s), reaction times were significantly shorter and we observed phase entrainment of EEG oscillations corresponding to the frequency of stimulus presentation (0.5?Hz), revealing an adjustment of the system to the regular stimulation. The amplitude of the entrained oscillation was higher for hits than for misses, suggesting a link between entrainment and stimulus detection. However, detection was independent of phase at frequencies ?1?Hz. Furthermore, we show that when the data are analyzed using acausal, though common, algorithms, an apparent “entrainment” of the ?-phase to presented stimuli emerges and detection probability appears to depend on ?-phase, similar to reports in the literature. We show that these effects are artifacts from phase distortion at stimulus onset by contamination with the event-related potential, which differs markedly for hits and misses. This highlights the need to carefully deal with this common problem, since otherwise it might bias and mislead this exciting field of research. PMID:23717293

  3. Hair cell regeneration in the European starling (Sturnus vulgaris): recovery of pure-tone detection thresholds.

    PubMed

    Marean, G C; Burt, J M; Beecher, M D; Rubel, E W

    1993-12-01

    Behavioral detection thresholds were obtained from four starlings before, during, and after 11 days of subcutaneous injections of kanamycin. Birds were operantly conditioned to respond to pure-tones ranging in frequency from 0.25 kHz to 7 kHz using the method of constant stimuli and were tested daily for 141 days after the first injection of aminoglycoside. All four birds sustained hearing losses greater than 60 dB at frequencies from 4 kHz to 7 kHz by the end of the 11 day injection schedule. Two birds had a slight shift in threshold at 3 kHz. No change in threshold occurred for any of the birds at lower frequencies. Recovery of detection thresholds began soon after the injections ceased and continued for approximately 50 days. In all four birds there was some degree of permanent hearing loss: 5 dB to 15 dB at frequencies between 4 kHz and 6 kHz, and approximately 25 dB at 7 kHz. Scanning electron microscopy (SEM) was performed at 0 and 5 days post-injection in a separate group of starlings given the same injection schedule. Hair cell loss and damage was observed across the basal 34% to 36% of the basilar papilla. SEM in two behaviorally tested birds sacrificed 142 days after the first injection showed that there was regeneration of hair cells to populate the previously damaged region, but that disorientation of stereocilia bundles in the basal third of the basilar papilla was common. The other two behaviorally tested birds were treated with kanamycin again for 16 days beginning at 142 days after the first injection. Thresholds shifted again, but less than during the first dosing period. SEM of these birds' basilar papillae showed less hair cell loss than observed in the birds given only a single, 11 day dosing of kanamycin. This result suggests that birds may be less susceptible to the ototoxic effects of kanamycin in repeated treatments. In all four birds, the degree and position of damage observed with SEM corresponded with the extent and frequency of hearing loss. PMID:8113131

  4. Detecting modulated signals in modulated noise: (II) neural thresholds in the songbird forebrain.

    PubMed

    Bee, Mark A; Buschermöhle, Michael; Klump, Georg M

    2007-10-01

    Sounds in the real world fluctuate in amplitude. The vertebrate auditory system exploits patterns of amplitude fluctuations to improve signal detection in noise. One experimental paradigm demonstrating these general effects has been used in psychophysical studies of 'comodulation detection difference' (CDD). The CDD effect refers to the fact that thresholds for detecting a modulated, narrowband noise signal are lower when the envelopes of flanking bands of modulated noise are comodulated with each other, but fluctuate independently of the signal compared with conditions in which the envelopes of the signal and flanking bands are all comodulated. Here, we report results from a study of the neural correlates of CDD in European starlings (Sturnus vulgaris). We manipulated: (i) the envelope correlations between a narrowband noise signal and a masker comprised of six flanking bands of noise; (ii) the signal onset delay relative to masker onset; (iii) signal duration; and (iv) masker spectrum level. Masked detection thresholds were determined from neural responses using signal detection theory. Across conditions, the magnitude of neural CDD ranged between 2 and 8 dB, which is similar to that reported in a companion psychophysical study of starlings [U. Langemann & G.M. Klump (2007) Eur. J. Neurosci., 26, 1969-1978]. We found little evidence to suggest that neural CDD resulted from the across-channel processing of auditory grouping cues related to common envelope fluctuations and synchronous onsets between the signal and flanking bands. We discuss a within-channel model of peripheral processing that explains many of our results. PMID:17897401

  5. MOA-2010-BLG-311: A PLANETARY CANDIDATE BELOW THE THRESHOLD OF RELIABLE DETECTION

    SciTech Connect

    Yee, J. C.; Hung, L.-W.; Gould, A.; Gaudi, B. S. [Department of Astronomy, Ohio State University, 140 West 18th Avenue, Columbus, OH 43210 (United States); Bond, I. A. [Institute for Information and Mathematical Sciences, Massey University, Private Bag 102-904, Auckland 1330 (New Zealand); Allen, W. [Vintage Lane Observatory, Blenheim (New Zealand); Monard, L. A. G. [Bronberg Observatory, Centre for Backyard Astrophysics, Pretoria (South Africa); Albrow, M. D. [Department of Physics and Astronomy, University of Canterbury, Private Bag 4800, Christchurch 8020 (New Zealand); Fouque, P. [IRAP, CNRS, Universite de Toulouse, 14 avenue Edouard Belin, F-31400 Toulouse (France); Dominik, M. [SUPA, University of St. Andrews, School of Physics and Astronomy, North Haugh, St. Andrews, KY16 9SS (United Kingdom); Tsapras, Y. [Las Cumbres Observatory Global Telescope Network, 6740B Cortona Drive, Goleta, CA 93117 (United States); Udalski, A. [Warsaw University Observatory, Al. Ujazdowskie 4, 00-478 Warszawa (Poland); Zellem, R. [Department of Planetary Sciences/LPL, University of Arizona, 1629 East University Boulevard, Tucson, AZ 85721 (United States); Bos, M. [Molehill Astronomical Observatory, North Shore City, Auckland (New Zealand); Christie, G. W. [Auckland Observatory, P.O. Box 24-180, Auckland (New Zealand); DePoy, D. L. [Department of Physics, Texas A and M University, 4242 TAMU, College Station, TX 77843-4242 (United States); Dong, Subo [Institute for Advanced Study, Einstein Drive, Princeton, NJ 08540 (United States); Drummond, J. [Possum Observatory, Patutahi (New Zealand); Gorbikov, E. [School of Physics and Astronomy, Raymond and Beverley Sackler Faculty of Exact Sciences, Tel-Aviv University, Tel Aviv 69978 (Israel); Han, C., E-mail: liweih@astro.ucla.edu, E-mail: rzellem@lpl.arizona.edu, E-mail: tim.natusch@aut.ac.nz [Department of Physics, Chungbuk National University, 410 Seongbong-Rho, Hungduk-Gu, Chongju 371-763 (Korea, Republic of); Collaboration: muFUN Collaboration; MOA Collaboration; OGLE Collaboration; PLANET Collaboration; RoboNet Collaboration; MiNDSTEp Consortium; and others

    2013-05-20

    We analyze MOA-2010-BLG-311, a high magnification (A{sub max} > 600) microlensing event with complete data coverage over the peak, making it very sensitive to planetary signals. We fit this event with both a point lens and a two-body lens model and find that the two-body lens model is a better fit but with only {Delta}{chi}{sup 2} {approx} 80. The preferred mass ratio between the lens star and its companion is q = 10{sup -3.7{+-}0.1}, placing the candidate companion in the planetary regime. Despite the formal significance of the planet, we show that because of systematics in the data the evidence for a planetary companion to the lens is too tenuous to claim a secure detection. When combined with analyses of other high-magnification events, this event helps empirically define the threshold for reliable planet detection in high-magnification events, which remains an open question.

  6. Input-output relation and energy efficiency in the neuron with different spike threshold dynamics

    PubMed Central

    Yi, Guo-Sheng; Wang, Jiang; Tsang, Kai-Ming; Wei, Xi-Le; Deng, Bin

    2015-01-01

    Neuron encodes and transmits information through generating sequences of output spikes, which is a high energy-consuming process. The spike is initiated when membrane depolarization reaches a threshold voltage. In many neurons, threshold is dynamic and depends on the rate of membrane depolarization (dV/dt) preceding a spike. Identifying the metabolic energy involved in neural coding and their relationship to threshold dynamic is critical to understanding neuronal function and evolution. Here, we use a modified Morris-Lecar model to investigate neuronal input-output property and energy efficiency associated with different spike threshold dynamics. We find that the neurons with dynamic threshold sensitive to dV/dt generate discontinuous frequency-current curve and type II phase response curve (PRC) through Hopf bifurcation, and weak noise could prohibit spiking when bifurcation just occurs. The threshold that is insensitive to dV/dt, instead, results in a continuous frequency-current curve, a type I PRC and a saddle-node on invariant circle bifurcation, and simultaneously weak noise cannot inhibit spiking. It is also shown that the bifurcation, frequency-current curve and PRC type associated with different threshold dynamics arise from the distinct subthreshold interactions of membrane currents. Further, we observe that the energy consumption of the neuron is related to its firing characteristics. The depolarization of spike threshold improves neuronal energy efficiency by reducing the overlap of Na+ and K+ currents during an action potential. The high energy efficiency is achieved at more depolarized spike threshold and high stimulus current. These results provide a fundamental biophysical connection that links spike threshold dynamics, input-output relation, energetics and spike initiation, which could contribute to uncover neural encoding mechanism. PMID:26074810

  7. Thresholds of Detection For Falling Snow From Satellite-Borne Active and Passive Sensors

    NASA Astrophysics Data System (ADS)

    Skofronick Jackson, G.; Johnson, B. T.; Munchak, S. J.

    2011-12-01

    Estimates of falling snow must be captured to obtain the true global precipitation water cycle and snowfall accumulations are required for hydrological studies. While satellite-based remote sensing provides global coverage of falling snow events and the science is relatively new, retrievals are still undergoing development with challenges remaining. The Global Precipitation Measurement (GPM) mission scheduled for launch in 2013 is specifically designed to measure both liquid rain and frozen snow precipitation. CloudSat is already collecting reflectivities of falling snow events. This work seeks to determine what snow events can be detected from passive and active spaceborne sensors using a theoretical analysis. These challenges of estimating falling snow include weak falling snow signatures with respect to background (surface, water vapor) signatures for passive sensors over land surfaces, unknowns about the spherical and non-spherical shapes of the snow flakes and their impact on observed brightness temperatures or radar reflectivities, differences in near surface snowfall and total column snow amounts, and limited ground truth to validate against. While these challenges remain, knowledge of their impact on expected retrieval results is an important key for understanding falling snow retrieval estimations. Information must be determined in order to guide retrieval algorithm development for the current and future missions. This information includes thresholds of detection for various sensor channel configurations, snow event system characteristics, and surface types. For example, can a lake effect snow system with low cloud tops having an ice water content (IWC) at the surface of 1.0 g m-3 be detected? If this information is known, we can focus retrieval efforts on detectable storms and concentrate advances on achievable results. The results rely on simulated Weather Research Forecasting (WRF) simulations of falling snow cases since simulations provide all the information to determine the measurements from space and the ground truth. In this work, the focus is to determine thresholds of detection for falling snow for various snow conditions over land and lake surfaces. The simulations are used to compute brightness temperatures (TBs) for channels from 10 to 183 GHz over the great lakes and snow-covered and snow-free surfaces. The models are also used to compute radar reflectivities (Z) at Ku, Ka, and W-bands. Both the Z and TB use the same cloud hydrometeors that allow for non-spherical snow and graupel particles. This work shows that under relatively perfect situations, that ice water paths (IWP) of ~4.0, 1.0, and 0.5 kg m-2 can be detected at 37, 89, and 166 GHz respectively. For active sensors such as those being designed for GPM and the current CloudSat radar, the minimum detectable signal by the sensor drives the thresholds of detection of falling snow near the surface range gates and is usually capable of detecting snow rates lower than that of passive sensors. This presentation will describe the procedure and results in detail.

  8. Error Probabilities and Threshold Selection in Networked Nuclear Detection Chetan D. Pahlajani, Jianxin Sun, Ioannis Poulakakis, Herbert G. Tanner

    E-print Network

    Poulakakis, Ioannis

    of nuclear detection relates to the problem of using radiation sensor data to decide, within a given time. Another challenge is that the signal recorded by the radiation detectors contains, in addition to possibleError Probabilities and Threshold Selection in Networked Nuclear Detection Chetan D. Pahlajani

  9. Electron-nuclear energy sharing in above-threshold multiphoton dissociative ionization of H2.

    PubMed

    Wu, J; Kunitski, M; Pitzer, M; Trinter, F; Schmidt, L Ph H; Jahnke, T; Magrakvelidze, M; Madsen, C B; Madsen, L B; Thumm, U; Dörner, R

    2013-07-12

    We report experimental observation of the energy sharing between electron and nuclei in above-threshold multiphoton dissociative ionization of H2 by strong laser fields. The absorbed photon energy is shared between the ejected electron and nuclei in a correlated fashion, resulting in multiple diagonal lines in their joint energy spectrum governed by the energy conservation of all fragment particles. PMID:23889391

  10. Energy threshold effects in the collisionless dissociation of polyatomic molecules by ir laser radiation

    NASA Technical Reports Server (NTRS)

    Gower, M. C.; Billman, K. W.

    1977-01-01

    The threshold for collisionless dissociation of SF6, SiF4, and CF2Cl2 by focused CO2 laser radiation has been measured. This threshold is a laser pulse energy effect and, within experimental error, is found to be the same for all three gases. Provided collisions cannot occur during the laser pulse, the degree of dissociation produced depends only on the energy in the pulse, which is consistent with simple adiabatic vibrational heating of the molecules by the laser.

  11. Neural variability, detection thresholds, and information transmission in the vestibular system.

    PubMed

    Sadeghi, Soroush G; Chacron, Maurice J; Taylor, Michael C; Cullen, Kathleen E

    2007-01-24

    A fundamental issue in neural coding is the role of spike timing variation in information transmission of sensory stimuli. Vestibular afferents are particularly well suited to study this issue because they are classified as either regular or irregular based on resting discharge variability as well as morphology. Here, we compared the responses of each afferent class to sinusoidal and random head rotations using both information theoretic and gain measures. Information theoretic measures demonstrated that regular afferents transmitted, on average, two times more information than irregular afferents, despite having significantly lower gains. Moreover, consistent with information theoretic measures, regular afferents had angular velocity detection thresholds that were 50% lower than those of irregular afferents (approximately 4 vs 8 degrees/s). Finally, to quantify the information carried by spike times, we added spike-timing jitter to the spike trains of both regular and irregular afferents. Our results showed that this significantly reduced information transmitted by regular afferents whereas it had little effect on irregular afferents. Thus, information is carried in the spike times of regular but not irregular afferents. Using a simple leaky integrate and fire model with a dynamic threshold, we show that differential levels of intrinsic noise can explain differences in the resting discharge, the responses to sensory stimuli, as well as the information carried by action potential timings of each afferent class. Our experimental and modeling results provide new insights as to how neural variability influences the strategy used by two different classes of sensory neurons to encode behaviorally relevant stimuli. PMID:17251416

  12. Probing nuclear symmetry energy with the sub-threshold pion production

    E-print Network

    Fang Zhang; Yang Liu; Gao-Chan Yong; Wei Zuo

    2012-04-05

    Within the framework of semiclassical Boltzmann-Uehling-Uhlenbeck (BUU) transport model, we investigated the effects of symmetry energy on the sub-threshold pion using the isospin MDI interaction with the stiff and soft symmetry energies in the central collision of $^{48}$Ca + $^{48}$Ca at the incident beam energies of 100, 150, 200, 250 and 300 MeV/nucleon, respectively. We find that the ratio of $\\pi^{-}/\\pi^{+}$ of sub-threshold charged pion production is greatly sensitive to the symmetry energy, particularly around 100 MeV/nucleon energies. Large sensitivity of sub-threshold charged pion production to nuclear symmetry energy may reduce uncertainties of probing nuclear symmetry energy via heavy-ion collision.

  13. Signal detection and threshold modeling of confidence-rating ROCs: A critical test with minimal assumptions.

    PubMed

    Kellen, David; Klauer, Karl Christoph

    2015-07-01

    An ongoing discussion in the recognition-memory literature concerns the question of whether recognition judgments reflect a direct mapping of graded memory representations (a notion that is instantiated by signal detection theory) or whether they are mediated by a discrete-state representation with the possibility of complete information loss (a notion that is instantiated by threshold models). These 2 accounts are usually evaluated by comparing their (penalized) fits to receiver operating characteristic data, a procedure that is predicated on substantial auxiliary assumptions, which if violated can invalidate results. We show that the 2 accounts can be compared on the basis of critical tests that invoke only minimal assumptions. Using previously published receiver operating characteristic data, we show that confidence-rating judgments are consistent with a discrete-state account. (PsycINFO Database Record PMID:26120910

  14. Bayesian decision threshold, detection limit and confidence limits in ionising-radiation measurement.

    PubMed

    Weise, K; Hübel, K; Rose, E; Schläger, M; Schrammel, D; Täschner, M; Michel, R

    2006-01-01

    Based on Bayesian statistics and the Bayesian theory of measurement uncertainty, characteristic limits such as the decision threshold, detection limit and limits of a confidence interval can be calculated taking into account all sources of uncertainty. This approach consists of the complete evaluation of a measurement according to the ISO Guide to the Expression of Uncertainty in Measurement (GUM) and the successive determination of the characteristic limits by using the standard uncertainty obtained from the evaluation. This procedure is elaborated here for several particular models of evaluation. It is, however, so general that it allows for a large variety of applications to similar measurements. It is proposed for the revision of those parts of DIN 25482 and ISO 11929 that are still based on conventional statistics and, therefore, do not allow to take completely into account all the components of measurement uncertainty in the calculation of the characteristic limits. PMID:16868015

  15. Dynamic thresholding for hyperspectral shadow detection using Levenberg-Marquardt minimization on multiple Gaussian illumination distributions

    NASA Astrophysics Data System (ADS)

    Wemett, Brian D.; Riek, Jonathan K.; Leathers, Robert A.

    2009-05-01

    Irregular illumination across a hyperspectral image makes it difficult to detect targets in shadows, perform change detection, and segment the contents of the scene. To correct for the data in shadow, we first convert the data from Cartesian space to a hyperspherical coordinate system. Each N-dimensional spectral vector is converted to N-1 spectral angles and a magnitude representing the illumination value of the spectra. Similar materials will have similar angles and the differences in illumination will be described mostly by the magnitude. In the data analyzed, we found that the distribution of illumination values is well approximated by the sum of two- Gaussian distributions, one for shadow and one for non-shadow. The Levenberg-Marquardt algorithm is used to fit the empirical illumination distribution to the theoretical Gaussian sum. The LM algorithm is an iterative technique that locates the minimum of a multivariate function that is expressed as the sum of squares of non-linear real-valued functions. Once the shadow and non-shadow distributions have been modeled, we find the optimal point to be one standard deviation out on the shadow distribution, allowing for the selection of about 84% of the shadows. This point is then used as a threshold to decide if the pixel is shadow or not. Corrections are made to the shadow regions and a spectral matched filter is applied to the image to test target detection in shadow regions. Results show a signal-to-noise gain over other illumination suppression techniques.

  16. Evaluation of a Change Detection Methodology by Means of Binary Thresholding Algorithms and Informational Fusion Processes

    PubMed Central

    Molina, Iñigo; Martinez, Estibaliz; Arquero, Agueda; Pajares, Gonzalo; Sanchez, Javier

    2012-01-01

    Landcover is subject to continuous changes on a wide variety of temporal and spatial scales. Those changes produce significant effects in human and natural activities. Maintaining an updated spatial database with the occurred changes allows a better monitoring of the Earth’s resources and management of the environment. Change detection (CD) techniques using images from different sensors, such as satellite imagery, aerial photographs, etc., have proven to be suitable and secure data sources from which updated information can be extracted efficiently, so that changes can also be inventoried and monitored. In this paper, a multisource CD methodology for multiresolution datasets is applied. First, different change indices are processed, then different thresholding algorithms for change/no_change are applied to these indices in order to better estimate the statistical parameters of these categories, finally the indices are integrated into a change detection multisource fusion process, which allows generating a single CD result from several combination of indices. This methodology has been applied to datasets with different spectral and spatial resolution properties. Then, the obtained results are evaluated by means of a quality control analysis, as well as with complementary graphical representations. The suggested methodology has also been proved efficiently for identifying the change detection index with the higher contribution. PMID:22737023

  17. Development Of An Electronic Nose For Environmental Monitoring: Detection Of Specific Environmentally Important Gases At Their Odor Detection Threshold Concentration

    NASA Astrophysics Data System (ADS)

    Dentoni, Licinia; Capelli, Laura; Sironi, Selena; Del Rosso, Renato; Centola, Paolo; Della Torre, Matteo; Demattè, Fabrizio

    2011-09-01

    The use of a sensor array is demonstrated to be an effective approach to evaluate hazardous odor (or gas) emissions from industrial sites1. Therefore the possibility to use electronic noses for the prolonged survey of odor emissions from industrial sites is of particular interest for environmental monitoring purposes2. At the Olfactometric Laboratory of the Politecnico di Milano, in collaboration with Sacmi Group, Imola, an innovative electronic nose for the continuous monitoring of environmental odors is being developed. The aim of this work is to show the laboratory tests conducted to evaluate the capability of the electronic nose to recognize some specific environmentally important gases at their odor detection threshold concentration. The laboratory studies up to now focused on ammonia and butyric acid, those being compounds that can typically be found in the emissions from waste treatment plants, that may cause health effects when they exceed a given concentration level. The laboratory tests proved the sensors to be sensitive towards the considered compounds and the system to be capable of discriminating between odorous or non-odorous air, with a detection limit comparable with the detection limit of human nose.

  18. AN ENERGY EFFICIENT SUB-THRESHOLD BASEBAND PROCESSOR ARCHITECTURE FOR PULSED ULTRA-WIDEBAND COMMUNICATIONS

    Microsoft Academic Search

    V. Sze; R. Blazquez; M. Bhardwaj; A. Chandrakasan

    2006-01-01

    This paper describes how parallelism in the digital baseband processor can reduce the energy required to receive ultra- wideband (UWB) packets. The supply voltage of the digital baseband is lowered so that the correlator operates near its minimum energy point resulting in a 68% energy reduction across the entire baseband. This optimum supply voltage occurs below the threshold voltage, placing

  19. Electron-Nuclear Energy Sharing in Above-Threshold Multiphoton Dissociative Ionization of H2

    E-print Network

    Thumm, Uwe

    Electron-Nuclear Energy Sharing in Above-Threshold Multiphoton Dissociative Ionization of H2 J. Wu­4], where the photon energy is shared by the freed electrons and the nuclear fragments. For the molecular ionization [10­15], and the imaging of inter- nuclear distance using nuclear kinetic energy release spec- tra

  20. Development of CDMS-II Surface Event Rejection Techniques and Their Extensions to Lower Energy Thresholds

    NASA Astrophysics Data System (ADS)

    Hofer, Thomas James

    The CDMS-II phase of the Cryogenic Dark Matter Search, a dark matter direct-detection experiment, was operated at the Soudan Underground Laboratory from 2003 to 2008. The full payload consisted of 30 ZIP detectors, totaling approximately 1.1 kg of Si and 4.8 kg of Ge, operated at temperatures of 50 mK. The ZIP detectors read out both ionization and phonon pulses from scatters within the crystals; channel segmentation and analysis of pulse timing parameters allowed effective fiducialization of the crystal volumes and background rejection sufficient to set world-leading limits at the times of their publications. A full re-analysis of the CDMS-II data was motivated by an improvement in the event reconstruction algorithms which improved the resolution of ionization energy and timing information. The Ge data were re-analyzed using three distinct background-rejection techniques; the Si data from runs 125--128 were analyzed for the first time using the most successful of the techniques from the Ge re-analysis. The results of these analyses prompted a novel "mid-threshold" analysis, wherein energy thresholds were lowered but background rejection using phonon timing information was still maintained. This technique proved to have significant discrimination power, maintaining adequate signal acceptance and minimizing background leakage. The primary background for CDMS-II analyses comes from surface events, whose poor ionization collection make them difficult to distinguish from true nuclear recoil events. The novel detector technology of SuperCDMS, the successor to CDMS-II, uses interleaved electrodes to achieve full ionization collection for events occurring at the top and bottom detector surfaces. This, along with dual-sided ionization and phonon instrumentation, allows for excellent fiducialization and relegates the surface-event rejection techniques of CDMS-II to a secondary level of background discrimination. Current and future SuperCDMS results hold great promise for mid- to low-mass WIMP-search results.

  1. Quantitative prediction of perceptual decisions during near-threshold fear detection

    NASA Astrophysics Data System (ADS)

    Pessoa, Luiz; Padmala, Srikanth

    2005-04-01

    A fundamental goal of cognitive neuroscience is to explain how mental decisions originate from basic neural mechanisms. The goal of the present study was to investigate the neural correlates of perceptual decisions in the context of emotional perception. To probe this question, we investigated how fluctuations in functional MRI (fMRI) signals were correlated with behavioral choice during a near-threshold fear detection task. fMRI signals predicted behavioral choice independently of stimulus properties and task accuracy in a network of brain regions linked to emotional processing: posterior cingulate cortex, medial prefrontal cortex, right inferior frontal gyrus, and left insula. We quantified the link between fMRI signals and behavioral choice in a whole-brain analysis by determining choice probabilities by means of signal-detection theory methods. Our results demonstrate that voxel-wise fMRI signals can reliably predict behavioral choice in a quantitative fashion (choice probabilities ranged from 0.63 to 0.78) at levels comparable to neuronal data. We suggest that the conscious decision that a fearful face has been seen is represented across a network of interconnected brain regions that prepare the organism to appropriately handle emotionally challenging stimuli and that regulate the associated emotional response. decision making | emotion | functional MRI

  2. The development of an adaptive threshold for model-based fault detection of a nonlinear electro-hydraulic system

    Microsoft Academic Search

    Z. Shi; F. Gu; B. Lennox; A. D. Ball

    2005-01-01

    This paper presents a practical approach to combine model-based fault detection with an adaptive threshold. The suitability of the proposed technique is illustrated through its application to the condition monitoring of a nonlinear electro-hydraulic plant. The paper begins by outlining the difficulties associated with modelling the plant and the steps taken to identify the uncertain factors that influence the accuracy

  3. Robust model-based detection of the lung field boundaries in portable chest radiographs supported by selective thresholding

    E-print Network

    Athens, University of

    Robust model-based detection of the lung field boundaries in portable chest radiographs supported of the lung field boundaries in portable chest radiographs supported by selective thresholding D K Iakovidis1, Technological Educational Institute of Lamia, GR-35100 Lamia, Greece 2 1st Department of Thoracic Surgery, Chest

  4. Ultrahigh Energy Cosmic Rays Detection

    E-print Network

    Carla Aramo

    2005-09-06

    The paper describes methods used for the detection of cosmic rays with energies above 10^18 eV (UHECR, UltraHigh Energy Cosmic Rays). It had been anticipated there would be a cutoff in the energy spectrum of primary cosmic rays around 3 10^19 eV induced by their interaction with the 2.7 K primordial photons. This has become known as the GZK cutoff. However, several showers have been detected with estimated primary energy exceeding this limit.

  5. Can receptor potentials be detected with threshold tracking in rat cutaneous nociceptive terminals?

    PubMed

    Sauer, S K; Weidner, C; Carr, R W; Averbeck, B; Nesnidal, U; Reeh, P W; Handwerker, H O

    2005-07-01

    Threshold tracking of individual polymodal C- and Adelta-fiber terminals was used to assess membrane potential changes induced by de- or hyperpolarizing stimuli in the isolated rat skin-nerve preparation. Constant current pulses were delivered (1 Hz) through a tungsten microelectrode inserted in the receptive field, and the current amplitude was controlled by feedback with a laboratory computer programmed to serially determine the electrical threshold using the method of limits. During threshold tracking, the receptive fields of the fibers were heated (32-46 degrees C in 210 s) or superfused with modified synthetic interstitial fluid containing either 0, 20, 40, 50, or 60 mM [K+], phosphate buffer to pH 5.2 or 6.1, or bradykinin (BK, 10(-8)-10(-5) M). High [K+]e decreased the current threshold for activation by 6-14% over 120 s, whereas K+-free superfusion augmented the threshold by >5%, and after some delay, also induced ongoing discharge in 60% of units. pH 6.1 and 5.2 caused an increase in threshold of 6 and 18%, respectively, and 30% of the fibers were excited by low pH, although the change in threshold of pH responsive and unresponsive fibers did not differ significantly, suggesting a general excitability decrease induced by protons. Heat stimulation increased the mean threshold and conduction velocity of the fibers tested and resulted in activity in 78% of units. Additionally, for these units, activation was preceded by a significant decrease in threshold compared with the tracked thresholds of fibers unresponsive to heat. Bradykinin also led to a significant threshold decrease before activation. In conclusion, the technique of threshold tracking proved suitable to assess changes in excitability resulting from receptor currents evoked by noxious heat and bradykinin in the terminal arborization of cutaneous nociceptors. PMID:15772238

  6. Design of a New Somatosensory Stimulus Delivery Device for Measuring Laryngeal Mechanosensory Detection Thresholds in Humans

    PubMed Central

    2009-01-01

    Laryngeal control is essential for airway protection, breathing, deglutition, speech, and voice. Unfortunately, integration of laryngeal sensory assessment in research and clinical practice is limited by technical and practical limitations of commercially available technology. A commercial device is available, but reported limitations include procedural complexity requiring two or three individuals to operate, limited stimulus dynamic range, device generated noise, and questionable stimulus reproducibility. The objective of this study was to design a new laryngeal somatosensory stimulus delivery device that provides direct, reliable control over the timing, duration, and dynamic range of stimulus presentation, and test the device in individuals who may manifest a laryngeal sensory deficit. The new device operates silently and has more than four times greater stimulus dynamic range than the commercial device. Testing with the new device revealed laryngeal mechanosensory detection thresholds in an individual with Parkinson’s disease that were seven times higher than those of healthy controls. These data would have otherwise gone undetected due to limited stimulus dynamic range in the commercial device. The new design resulted in a new assessment instrument that is simple to use for routine clinical assessment, yet sufficiently versatile for integration within rigorous clinical research protocols. PMID:19272888

  7. First demonstration of a sub-keV electron recoil energy threshold in a liquid argon ionization chamber

    E-print Network

    S. Sangiorgio; T. H. Joshi; A. Bernstein; J. Coleman; M. Foxe; C. Hagmann; I. Jovanovic; K. Kazkaz; K. Mavrokoridis; V. Mozin; S. Pereverzev; P. Sorensen

    2013-07-19

    We describe the first demonstration of a sub-keV electron recoil energy threshold in a dual-phase liquid argon time projection chamber. This is an important step in an effort to develop a detector capable of identifying the ionization signal resulting from nuclear recoils with energies of order a few keV and below. We obtained this result by observing the peaks in the energy spectrum at 2.82 keV and 0.27 keV, following the K- and L-shell electron capture decay of Ar-37, respectively. The Ar-37 source preparation is described in detail, since it enables calibration that may also prove useful in dark matter direct detection experiments. An internally placed Fe-55 x-ray source simultaneously provided another calibration point at 5.9 keV. We discuss the ionization yield and electron recombination in liquid argon at those three calibration energies.

  8. First demonstration of a sub-keV electron recoil energy threshold in a liquid argon ionization chamber

    NASA Astrophysics Data System (ADS)

    Sangiorgio, S.; Joshi, T. H.; Bernstein, A.; Coleman, J.; Foxe, M.; Hagmann, C.; Jovanovic, I.; Kazkaz, K.; Mavrokoridis, K.; Mozin, V.; Pereverzev, S.; Sorensen, P.

    2013-11-01

    We describe the first demonstration of a sub-keV electron recoil energy threshold in a dual-phase liquid argon time projection chamber. This is an important step in an effort to develop a detector capable of identifying the ionization signal resulting from nuclear recoils with energies of order a few keV and below. We obtained this result by observing the peaks in the energy spectrum at 2.82 keV and 0.27 keV, following the K- and L-shell electron capture decay of 37Ar respectively. The 37Ar source preparation is described in detail, since it enables calibration that may also prove useful in dark matter direct detection experiments. An internally placed 55Fe x-ray source simultaneously provided another calibration point at 5.9 keV. We discuss the ionization yield and electron recombination in liquid argon at those three calibration energies.

  9. Molecular dynamics simulations of threshold displacement energies in Fe

    E-print Network

    Nordlund, Kai

    be well predicted by the Kinchin­Pease (or its variation NRT [3]) equation which states that the amount displacement energy EÃ d [4]. Even in materials where the Kinchin­Pease equation is not valid, typically dense of defects compared to the Kinchin­Pease prediction [5,6]. Because of this, it is of importance to know

  10. Determination of energy thresholds on an artificial retina using a multiple-pulsed laser

    E-print Network

    Stephenson, Albert David

    1999-01-01

    This study is focused on determining single and multiple pulse ED?? for laser pulses of 200 ns duration. Energy thresholds in this experiment were determined on an artificial retina, for a variety of pulse widths and spot sizes. Due to numerous...

  11. Determination of navigation FDI thresholds using a Markov model. [Failure Detection and Identification in triplex inertial platform systems for Shuttle entry

    NASA Technical Reports Server (NTRS)

    Walker, B. K.; Gai, E.

    1978-01-01

    A method for determining time-varying Failure Detection and Identification (FDI) thresholds for single sample decision functions is described in the context of a triplex system of inertial platforms. A cost function consisting of the probability of vehicle loss due to FDI decision errors is minimized. A discrete Markov model is constructed from which this cost can be determined as a function of the decision thresholds employed to detect and identify the first and second failures. Optimal thresholds are determined through the use of parameter optimization techniques. The application of this approach to threshold determination is illustrated for the Space Shuttle's inertial measurement instruments.

  12. Stealth Transmission over a WDM Network with Detection Based on an All-Optical Thresholder

    Microsoft Academic Search

    K. Kravtsov; B. Wu; I. Glysk; P. R. Prucnal; E. Narimanov

    2007-01-01

    An experimental demonstration of stealth transmission over a public WDM network is presented. An all-optical thresholder is utilized to minimize the power in the stealth channel, enabling efficient channel hiding in both time and spectral domains.

  13. Neutron capture reaction in oxygen nuclei near threshold energy regions

    SciTech Connect

    Yamamoto, K.; Ohta, M. [Department of Physics, Konan University, 8-9-1 Okamoto, Kobe 658-8501 (Japan); Masui, H. [Information Processing Center, Kitami Institute of Technology, Kitami 090-8507 (Japan); Kato, K. [Division of Physics, Hokkaido University, Sapporo 060-0810 (Japan); Wada, T. [Department of Pure and Applied Physics, Kansai University, 3-3-35 Yamate-cho, Suita 564-8680 (Japan)

    2008-05-21

    For the key reactions {sup 16}O(n,{gamma}){sup 17}O and {sup 17}O(n,{gamma}){sup 18}O on nucleosyntheses in stellar interior, the theoretical estimate for the cross section and reaction rate have been made. The careful description of the nuclear structure is important in very low energy regions. The Cluster Orbital Shell Model is adopted for reproducing the structure of the nuclei. Our results for the cross section of the {sup 16}O(n,{gamma}){sup 17}O reaction are consistent with that of the microscopic two cluster model. The straightforward application becames possible to the case of the {sup 17}O(n,{gamma}){sup 18}O reaction with a substantial reliance.

  14. SAM Thresholding and False Discovery Rates for Detecting Differential Gene Expression in DNA Microarrays

    Microsoft Academic Search

    John D. Storey; Robert Tibshirani

    SAM is a computer package for correlating gene expression with an outcome parameter such as treatment, survival time, or diagnostic class. It thresholds an appropriate test statistic and reports the q-value of each test based on a set of sample permutations. SAM works as a Microsoft Excel add-in and has additional features for fold-change thresholding and block permutations. Here, we

  15. First demonstration of a sub-keV electron recoil energy threshold in a liquid argon ionization chamber

    E-print Network

    Sangiorgio, S; Coleman, J; Foxe, M; Hagmann, C; Joshi, T H; Jovanovic, I; Kazkaz, K; Mavrokoridis, K; Mozin, V; Pereverzev, S; Sorensen, P

    2013-01-01

    We make a first demonstration of a sub-keV electron recoil energy threshold in a dual-phase liquid argon time-projection chamber. This is an important step in a program to build a detector capable of identifying the ionization signal resulting from nuclear recoils at a few keV and below. We obtained this result by observing the peaks in the energy spectrum at 2.82 keV and 0.27 keV, following the K- and L-shell electron capture decay of Ar-37. We describe the details of the Ar-37 source preparation, as this calibration technique may prove useful, e.g. for dark matter direct detection experiments. A Fe-55 internal x-ray source was also measured simultaneously and provided another calibration point at 5.9 keV. We discuss the ionization yield and electron recombination in liquid argon at the three calibration energies.

  16. Direct measurement of the bubble-nucleation energy threshold in a CF3I bubble chamber

    NASA Astrophysics Data System (ADS)

    Behnke, E.; Benjamin, T.; Brice, S. J.; Broemmelsiek, D.; Collar, J. I.; Cooper, P. S.; Crisler, M.; Dahl, C. E.; Fustin, D.; Hall, J.; Harnish, C.; Levine, I.; Lippincott, W. H.; Moan, T.; Nania, T.; Neilson, R.; Ramberg, E.; Robinson, A. E.; Ruschman, M.; Sonnenschein, A.; Vázquez-Jáuregui, E.; Rivera, R. A.; Uplegger, L.

    2013-07-01

    We have directly measured the energy threshold and efficiency for bubble nucleation from iodine recoils in a CF3I bubble chamber in the energy range of interest for a dark matter search. These interactions cannot be probed by standard neutron calibration methods, so we develop a new technique by observing the elastic scattering of 12GeV/c negative pions. The pions are tracked with a silicon pixel telescope and the reconstructed scattering angle provides a measure of the nuclear recoil kinetic energy. The bubble chamber was operated with a nominal threshold of (13.6±0.6)keV. Interpretation of the results depends on the response to fluorine and carbon recoils, but in general we find agreement with the predictions of the classical bubble-nucleation theory. This measurement confirms the applicability of CF3I as a target for spin-independent dark matter interactions and represents a novel technique for calibration of superheated fluid detectors.

  17. Direct Measurement of the Bubble Nucleation Energy Threshold in a CF3I Bubble Chamber

    E-print Network

    Behnke, E; Brice, S J; Broemmelsiek, D; Collar, J I; Cooper, P S; Crisler, M; Dahl, C E; Fustin, D; Hall, J; Harnish, C; Levine, I; Lippincott, W H; Moan, T; Nania, T; Neilson, R; Ramberg, E; Robinson, A E; Sonnenschein, A; Vázquez-Jáuregui, E; Rivera, R A; Uplegger, L

    2013-01-01

    We have directly measured the energy threshold and efficiency for bubble nucleation from iodine recoils in a CF3I bubble chamber in the energy range of interest for a dark matter search. These interactions cannot be probed by standard neutron calibration methods, so we develop a new technique by observing the elastic scattering of 12 GeV/c negative pions. The pions are tracked with a silicon pixel telescope and the reconstructed scattering angle provides a measure of the nuclear recoil kinetic energy. The bubble chamber was operated with a nominal threshold of (13.6+-0.6) keV. Interpretation of the results depends on the response to fluorine and carbon recoils, but in general we find agreement with the predictions of the classical bubble nucleation theory. This measurement confirms the applicability of CF3I as a target for spin-independent dark matter interactions and represents a novel technique for calibration of superheated fluid detectors.

  18. Direct Measurement of the Bubble Nucleation Energy Threshold in a CF3I Bubble Chamber

    E-print Network

    COUPP Collaboration; E. Behnke; T. Benjamin; S. J. Brice; D. Broemmelsiek; J. I. Collar; P. S. Cooper; M. Crisler; C. E. Dahl; D. Fustin; J. Hall; C. Harnish; I. Levine; W. H. Lippincott; T. Moan; T. Nania; R. Neilson; E. Ramberg; A. E. Robinson; A. Sonnenschein; E. Vázquez-Jáuregui; R. A. Rivera; L. Uplegger

    2014-01-31

    We have directly measured the energy threshold and efficiency for bubble nucleation from iodine recoils in a CF3I bubble chamber in the energy range of interest for a dark matter search. These interactions cannot be probed by standard neutron calibration methods, so we develop a new technique by observing the elastic scattering of 12 GeV/c negative pions. The pions are tracked with a silicon pixel telescope and the reconstructed scattering angle provides a measure of the nuclear recoil kinetic energy. The bubble chamber was operated with a nominal threshold of (13.6+-0.6) keV. Interpretation of the results depends on the response to fluorine and carbon recoils, but in general we find agreement with the predictions of the classical bubble nucleation theory. This measurement confirms the applicability of CF3I as a target for spin-independent dark matter interactions and represents a novel technique for calibration of superheated fluid detectors.

  19. Homoclinic bifurcation threshold of a bistable system for piezoelectric energy harvesting

    NASA Astrophysics Data System (ADS)

    Li, Haitao; Qin, Weiyang

    2015-02-01

    In this work, we study the homoclinic bifurcation threshold of a bistable energy harvesting system, which can be used to determine the presence of the high energy orbit and improve the harvesting efficiency. The equivalent mathematical model of piezoelectric beam compressed by axial force is proposed, which becomes a bistable energy harvester as axial load goes beyond the critical load. Based on Melnikov theory, a global method is presented to qualitatively analyze the motion of the system when it is excited by harmonic base motion. From the global method, the criteria of homoclinic bifurcation are derived. The analysis results are verified via bifurcation diagram and Lyapunov exponent. Numerical simulations show that cross-well oscillation occurs as critical threshold condition is satisfied, which makes the power ratio between output and input reach the maximum. The agreements between the analytical results and those from numerical simulation validate the effectiveness of the proposed technique.

  20. Empirical Bayesian random censoring threshold model improves detection of differentially abundant proteins.

    PubMed

    Koopmans, Frank; Cornelisse, L Niels; Heskes, Tom; Dijkstra, Tjeerd M H

    2014-09-01

    A challenge in proteomics is that many observations are missing with the probability of missingness increasing as abundance decreases. Adjusting for this informative missingness is required to assess accurately which proteins are differentially abundant. We propose an empirical Bayesian random censoring threshold (EBRCT) model that takes the pattern of missingness in account in the identification of differential abundance. We compare our model with four alternatives, one that considers the missing values as missing completely at random (MCAR model), one with a fixed censoring threshold for each protein species (fixed censoring model) and two imputation models, k-nearest neighbors (IKNN) and singular value thresholding (SVTI). We demonstrate that the EBRCT model bests all alternative models when applied to the CPTAC study 6 benchmark data set. The model is applicable to any label-free peptide or protein quantification pipeline and is provided as an R script. PMID:25102230

  1. The energy distribution cross section in threshold electron-atom impact ionization

    NASA Technical Reports Server (NTRS)

    Temkin, A.

    1974-01-01

    The flatness of the energy differential cross section in impact ionization is derived analytically in the Wannier theory. However it is shown that the Wannier zone is confined to a region of the order E/5 is less than or equal to epsilon is less than or equal to 4E/5, where E is the available energy and epsilon is the energy of the electrons. By contrasting the known results of photoionization and photodetachment, one can cogently argue that in the complementary region where electrons share their energy very unequally the cross section rises to a value independent of E, and that this region determines the form of the threshold law.

  2. Ab initio molecular dynamics simulations of threshold displacement energies in SrTiO3

    SciTech Connect

    Liu, Bin [ORNL] [ORNL; Xiao, Haiyan [University of Tennessee, Knoxville (UTK)] [University of Tennessee, Knoxville (UTK); Zhang, Yanwen [ORNL] [ORNL; Aidhy, Dilpuneet S [ORNL] [ORNL; Weber, William J [ORNL] [ORNL

    2013-01-01

    Ab initio molecular dynamics simulations have been carried out to study low-energy recoil events in SrTiO3. The threshold displacement energies are shown to be strongly dependent on both the orientation and the corresponding atomic arrangement. The minimum threshold displacement energies are 13 eV for an O recoil along the <100> O-O chain, 25 eV for a Sr recoil along the <100> Sr-Sr chain and 38 eV for a Ti recoil along the <110> Ti-Ti chain. The weighted average threshold displacement energies along the primary crystallographic directions are 35.7, 53.5 and > 64.9 eV for O, Sr and Ti, respectively. The interstitial configurations produced by the recoil events are <100> and <111> split-interstitials for O and Sr, respectively, together with a Ti interstitial occupying a distorted bridge position between two Sr sites. It is found that the recoil events in SrTiO3 are partial- charge transfer assisted processes, and the partial- charge transfer plays an important role in these recoil events.

  3. Determination of ortho- and retronasal detection thresholds and odor impact of 2,5-dimethyl-3-methoxypyrazine in wine.

    PubMed

    Botezatu, Andreea; Pickering, Gary J

    2012-11-01

    2,5-Dimethyl-3-methoxypyrazine (DMMP) has been recently identified in both Coccinellidae-tainted (by either Coccinella septempunctata or Harmonia axyridis beetles) and untainted wines; however, little is known regarding its impact on wine aroma and flavor. The aims of this study were to obtain an accurate estimate of both the ortho- and retronasal detection thresholds of DMMP in red wine and to understand how DMMP contributes to the aroma profile of red wine. In the first study, thresholds were determined for 21 individuals using the ASTM E679 ascending forced choice method of limits. The orthonasal group best estimate threshold (BET) was 31 ng/L and the retronasal group BET was 70 ng/L. A moderate variation in individual thresholds was observed for the orthonasal modality (standard deviation (SD) = 19.8) and a larger variation was noted for retronasal thresholds (SD = 111.8). In the second study, a panel of 8 assessors performed descriptive sensory analysis on 3 red wines containing various concentrations of added DMMP (0, 50, and 120 ng/L). Results show significant changes in aroma characteristics in the 120 ng/L wine and smaller effects at the 50 ng/L level. Overall, wines spiked with DMMP generated lower intensity ratings for cherry and red berry descriptors and higher ratings for earthy/musty and green/vegetal descriptors. When considered with other recent results on DMMP concentrations found in wine, DMMP can be considered a hitherto undescribed impact odorant in some wine styles. PMID:23057415

  4. A Wideband Spectrum-Sensing Processor With Adaptive Detection Threshold and Sensing Time

    Microsoft Academic Search

    Tsung-Han Yu; Oussama Sekkat; Santiago Rodriguez-Parera; Dejan Markovic ´; Danijela Cabric

    2011-01-01

    Spectrum sensing over a wide bandwidth increases the probability of finding unutilized spectrum for cognitive radios. The hardware realization of wideband sensing is challenging because strong primary users introduce large dynamic range and spectral leakage in adjacent unused bands. This paper proposes a multitap-windowed frequency power detector with adaptive threshold and sensing time to address the above challenges. The suppression

  5. DETECTION AND IDENTIFICATION THRESHOLD VALUES FOR KEY FLAVOR COMPONENTS IN AN ORANGE JUICE MATRIX

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Due to the complex nature of orange juice, threshold values for key flavor components could differ significantly from those values reported in simpler systems, like water. In order to provide the citrus industry with reference values closer to the real situation in orange juice, different orange ju...

  6. The photodetachment cross-section and threshold energy of negative ions in carbon dioxide

    NASA Technical Reports Server (NTRS)

    Helmy, E. M.; Woo, S. B.

    1974-01-01

    Threshold energy and sunlight photodetachment measurements on negative carbon dioxide ions, using a 2.5 kw light pressure xenon lamp, show that: (1) Electron affinity of CO3(+) is larger than 2.7 e.V. and that an isomeric form of CO3(+) is likely an error; (2) The photodetachment cross section of CO3(-) will roughly be like a step function across the range of 4250 to 2500A, having its threshold energy at 4250A; (3) Sunlight photodetachment rate for CO3(-) is probably much smaller than elsewhere reported; and (4) The probability of having photodetached electrons re-attach to form negative ions is less than 1%. Mass identifying drift tube tests confirm that the slower ion is CO3(-), formed through the O(-) + 2CO2 yields CO3(-) + CO2 reaction.

  7. Sensitivity and Specificity of Interictal EEG-fMRI for Detecting the Ictal Onset Zone at Different Statistical Thresholds.

    PubMed

    Tousseyn, Simon; Dupont, Patrick; Goffin, Karolien; Sunaert, Stefan; Van Paesschen, Wim

    2014-01-01

    There is currently a lack of knowledge about electroencephalography (EEG)-functional magnetic resonance imaging (fMRI) specificity. Our aim was to define sensitivity and specificity of blood oxygen level dependent (BOLD) responses to interictal epileptic spikes during EEG-fMRI for detecting the ictal onset zone (IOZ). We studied 21 refractory focal epilepsy patients who had a well-defined IOZ after a full presurgical evaluation and interictal spikes during EEG-fMRI. Areas of spike-related BOLD changes overlapping the IOZ in patients were considered as true positives; if no overlap was found, they were treated as false-negatives. Matched healthy case-controls had undergone similar EEG-fMRI in order to determine true-negative and false-positive fractions. The spike-related regressor of the patient was used in the design matrix of the healthy case-control. Suprathreshold BOLD changes in the brain of controls were considered as false positives, absence of these changes as true negatives. Sensitivity and specificity were calculated for different statistical thresholds at the voxel level combined with different cluster size thresholds and represented in receiver operating characteristic (ROC)-curves. Additionally, we calculated the ROC-curves based on the cluster containing the maximal significant activation. We achieved a combination of 100% specificity and 62% sensitivity, using a Z-threshold in the interval 3.4-3.5 and cluster size threshold of 350 voxels. We could obtain higher sensitivity at the expense of specificity. Similar performance was found when using the cluster containing the maximal significant activation. Our data provide a guideline for different EEG-fMRI settings with their respective sensitivity and specificity for detecting the IOZ. The unique cluster containing the maximal significant BOLD activation was a sensitive and specific marker of the IOZ. PMID:25101049

  8. Red-shifted carrier multiplication energy threshold and exciton recycling mechanisms in strongly interacting silicon nanocrystals.

    PubMed

    Marri, Ivan; Govoni, Marco; Ossicini, Stefano

    2014-09-24

    We present density functional theory calculations of carrier multiplication properties in a system of strongly coupled silicon nanocrystals. Our results suggest that nanocrystal-nanocrystal interaction can lead to a reduction of the carrier multiplication energy threshold without altering the carrier multiplication efficiency at high energies, in agreement with experiments. The time evolution of the number of electron-hole pairs generated in a system of strongly interacting nanocrystals upon absorption of high-energy photons is analyzed by solving a system of coupled rate equations, where exciton recycling mechanisms are implemented. We reconsider the role played by Auger recombination which is here accounted also as an active, nondetrimental process. PMID:25092549

  9. Limiting absorption principle for some long range perturbations of Dirac systems at threshold energies

    E-print Network

    Nabile Boussaid; Sylvain Golénia

    2009-06-08

    We establish a limiting absorption principle for some long range perturbations of the Dirac systems at threshold energies. We cover multi-center interactions with small coupling constants. The analysis is reduced to study a family of non-self-adjoint operators. The technique is based on a positive commutator theory for non self-adjoint operators, which we develop in appendix. We also discuss some applications to the dispersive Helmholzt model in the quantum regime.

  10. Dynamics of strangeness production in heavy-ion collisions near threshold energies

    Microsoft Academic Search

    Zhao-Qing Fengand; Gen-Ming Jin

    2010-01-01

    Within the framework of the improved isospin-dependent quantum molecular dynamics (ImIQMD) model, the dynamics of strangeness (K0,+, Lambda, and Sigma-,0,+) production in heavy-ion collisions near threshold energies is investigated systematically, with the strange particles considered to be produced mainly by inelastic collisions of baryon-baryon and pion-baryon. Collisions in the region of suprasaturation densities of the dense baryonic matter formed in

  11. Dynamics of strangeness production in heavy-ion collisions near threshold energies

    Microsoft Academic Search

    Feng Zhaoqing; Jin Genming

    2010-01-01

    Within the framework of the improved isospin-dependent quantum molecular dynamics (ImIQMD) model, the dynamics of strangeness (K{sup 0,+}, , and {sup -,0,+}) production in heavy-ion collisions near threshold energies is investigated systematically, with the strange particles considered to be produced mainly by inelastic collisions of baryon-baryon and pion-baryon. Collisions in the region of suprasaturation densities of the dense baryonic matter

  12. Adaptive thresholding and dynamic windowing method for automatic centroid detection of digital Shack-Hartmann wavefront sensor

    SciTech Connect

    Yin Xiaoming; Li Xiang; Zhao Liping; Fang Zhongping

    2009-11-10

    A Shack-Hartmann wavefront sensor (SWHS) splits the incident wavefront into many subsections and transfers the distorted wavefront detection into the centroid measurement. The accuracy of the centroid measurement determines the accuracy of the SWHS. Many methods have been presented to improve the accuracy of the wavefront centroid measurement. However, most of these methods are discussed from the point of view of optics, based on the assumption that the spot intensity of the SHWS has a Gaussian distribution, which is not applicable to the digital SHWS. In this paper, we present a centroid measurement algorithm based on the adaptive thresholding and dynamic windowing method by utilizing image processing techniques for practical application of the digital SHWS in surface profile measurement. The method can detect the centroid of each focal spot precisely and robustly by eliminating the influence of various noises, such as diffraction of the digital SHWS, unevenness and instability of the light source, as well as deviation between the centroid of the focal spot and the center of the detection area. The experimental results demonstrate that the algorithm has better precision, repeatability, and stability compared with other commonly used centroid methods, such as the statistical averaging, thresholding, and windowing algorithms.

  13. Comparison of Threshold Detection Methods for the Generalized Pareto Distribution (GPD): Application to the NOAA-NCDC Daily Rainfall Dataset

    NASA Astrophysics Data System (ADS)

    Deidda, Roberto; Mamalakis, Antonis; Langousis, Andreas

    2015-04-01

    One of the most crucial issues in statistical hydrology is the estimation of extreme rainfall from data. To that extent, based on asymptotic arguments from Extreme Excess (EE) theory, several studies have focused on developing new, or improving existing methods to fit a Generalized Pareto Distribution (GPD) model to rainfall excesses above a properly selected threshold u. The latter is generally determined using various approaches that can be grouped into three basic classes: a) non-parametric methods that locate the changing point between extreme and non-extreme regions of the data, b) graphical methods where one studies the dependence of the GPD parameters (or related metrics) to the threshold level u, and c) Goodness of Fit (GoF) metrics that, for a certain level of significance, locate the lowest threshold u that a GPD model is applicable. In this work, we review representative methods for GPD threshold detection, discuss fundamental differences in their theoretical bases, and apply them to daily rainfall records from the NOAA-NCDC open-access database (http://www.ncdc.noaa.gov/oa/climate/ghcn-daily/). We find that non-parametric methods that locate the changing point between extreme and non-extreme regions of the data are generally not reliable, while graphical methods and GoF metrics that rely on limiting arguments for the upper distribution tail lead to unrealistically high thresholds u. The latter is expected, since one checks the validity of the limiting arguments rather than the applicability of a GPD distribution model. Better performance is demonstrated by graphical methods and GoF metrics that rely on GPD properties. Finally, we discuss the effects of data quantization (common in hydrologic applications) on the estimated thresholds. Acknowledgments: The research project is implemented within the framework of the Action «Supporting Postdoctoral Researchers» of the Operational Program "Education and Lifelong Learning" (Action's Beneficiary: General Secretariat for Research and Technology), and is co-financed by the European Social Fund (ESF) and the Greek State.

  14. Detecting Fragmentation Extinction Thresholds for Forest Understory Plant Species in Peninsular Spain

    PubMed Central

    Rueda, Marta; Moreno Saiz, Juan Carlos; Morales-Castilla, Ignacio; Albuquerque, Fabio S.; Ferrero, Mila; Rodríguez, Miguel Á.

    2015-01-01

    Ecological theory predicts that fragmentation aggravates the effects of habitat loss, yet empirical results show mixed evidences, which fail to support the theory instead reinforcing the primary importance of habitat loss. Fragmentation hypotheses have received much attention due to their potential implications for biodiversity conservation, however, animal studies have traditionally been their main focus. Here we assess variation in species sensitivity to forest amount and fragmentation and evaluate if fragmentation is related to extinction thresholds in forest understory herbs and ferns. Our expectation was that forest herbs would be more sensitive to fragmentation than ferns due to their lower dispersal capabilities. Using forest cover percentage and the proportion of this percentage occurring in the largest patch within UTM cells of 10-km resolution covering Peninsular Spain, we partitioned the effects of forest amount versus fragmentation and applied logistic regression to model occurrences of 16 species. For nine models showing robustness according to a set of quality criteria we subsequently defined two empirical fragmentation scenarios, minimum and maximum, and quantified species’ sensitivity to forest contraction with no fragmentation, and to fragmentation under constant forest cover. We finally assessed how the extinction threshold of each species (the habitat amount below which it cannot persist) varies under no and maximum fragmentation. Consistent with their preference for forest habitats probability occurrences of all species decreased as forest cover contracted. On average, herbs did not show significant sensitivity to fragmentation whereas ferns were favored. In line with theory, fragmentation yielded higher extinction thresholds for two species. For the remaining species, fragmentation had either positive or non-significant effects. We interpret these differences as reflecting species-specific traits and conclude that although forest amount is of primary importance for the persistence of understory plants, to neglect the impact of fragmentation for some species can lead them to local extinction. PMID:25978329

  15. In vivo transcranial cavitation threshold detection during ultrasound-induced blood-brain barrier opening in mice

    NASA Astrophysics Data System (ADS)

    Tung, Yao-Sheng; Vlachos, Fotios; Choi, James J.; Deffieux, Thomas; Selert, Kirsten; Konofagou, Elisa E.

    2010-10-01

    The in vivo cavitation response associated with blood-brain barrier (BBB) opening as induced by transcranial focused ultrasound (FUS) in conjunction with microbubbles was studied in order to better identify the underlying mechanism in its noninvasive application. A cylindrically focused hydrophone, confocal with the FUS transducer, was used as a passive cavitation detector (PCD) to identify the threshold of inertial cavitation (IC) in the presence of Definity® microbubbles (mean diameter range: 1.1-3.3 µm, Lantheus Medical Imaging, MA, USA). A vessel phantom was first used to determine the reliability of the PCD prior to in vivo use. A cerebral blood vessel was simulated by generating a cylindrical channel of 610 µm in diameter inside a polyacrylamide gel and by saturating its volume with microbubbles. The microbubbles were sonicated through an excised mouse skull. Second, the same PCD setup was employed for in vivo noninvasive (i.e. transdermal and transcranial) cavitation detection during BBB opening. After the intravenous administration of Definity® microbubbles, pulsed FUS was applied (frequency: 1.525 or 1.5 MHz, peak-rarefactional pressure: 0.15-0.60 MPa, duty cycle: 20%, PRF: 10 Hz, duration: 1 min with a 30 s interval) to the right hippocampus of twenty-six (n = 26) mice in vivo through intact scalp and skull. T1 and T2-weighted MR images were used to verify the BBB opening. A spectrogram was generated at each pressure in order to detect the IC onset and duration. The threshold of BBB opening was found to be at a 0.30 MPa peak-rarefactional pressure in vivo. Both the phantom and in vivo studies indicated that the IC pressure threshold had a peak-rarefactional amplitude of 0.45 MPa. This indicated that BBB opening may not require IC at or near the threshold. Histological analysis showed that BBB opening could be induced without any cellular damage at 0.30 and 0.45 MPa. In conclusion, the cavitation response could be detected without craniotomy in mice and IC may not be required for BBB opening at relatively low pressures.

  16. Pressure and particle motion detection thresholds in fish: a re-examination of salient auditory cues in teleosts.

    PubMed

    Radford, Craig A; Montgomery, John C; Caiger, Paul; Higgs, Dennis M

    2012-10-01

    The auditory evoked potential technique has been used for the past 30 years to evaluate the hearing ability of fish. The resulting audiograms are typically presented in terms of sound pressure (dB re. 1 ?Pa) with the particle motion (dB re. 1 m s(-2)) component largely ignored until recently. When audiograms have been presented in terms of particle acceleration, one of two approaches has been used for stimulus characterisation: measuring the pressure gradient between two hydrophones or using accelerometers. With rare exceptions these values are presented from experiments using a speaker as the stimulus, thus making it impossible to truly separate the contribution of direct particle motion and pressure detection in the response. Here, we compared the particle acceleration and pressure auditory thresholds of three species of fish with differing hearing specialisations, goldfish (Carassius auratus, weberian ossicles), bigeye (Pempheris adspersus, ligamentous hearing specialisation) and a third species with no swim bladder, the common triplefin (Forstergyian lappillum), using three different methods of determining particle acceleration. In terms of particle acceleration, all three fish species have similar hearing thresholds, but when expressed as pressure thresholds goldfish are the most sensitive, followed by bigeye, with triplefin the least sensitive. It is suggested here that all fish have a similar ability to detect the particle motion component of the sound field and it is their ability to transduce the pressure component of the sound field to the inner ear via ancillary hearing structures that provides the differences in hearing ability. Therefore, care is needed in stimuli presentation and measurement when determining hearing ability of fish and when interpreting comparative hearing abilities between species. PMID:22693030

  17. Flux threshold of He-ion-beam induced nano-fuzz growth on hot tungsten below and above the displacement damage threshold energy

    NASA Astrophysics Data System (ADS)

    Hijazi, Hussein; Bannister, Mark E.; Parish, Chad M.; Meyer, Harry M., III; Meyer, Fred W.

    2014-10-01

    Measurements of nano-fuzz growth on linear plasma devices have shown that below the displacement damage energy threshold, a minimum He-ion flux is required for nano-fuzz formation. We report comparative measurements of nano-fuzz flux thresholds below and above the displacement damage energy threshold using well characterized He ion beams at the ORNL MIRF. He-ion-beam flux distributions were optimized and measured at 218 and 2000 eV prior to ion beam impact on W coupons heated to about 1000 deg. C. After exposure times ranging from 4200 to 7200 seconds, the beam spots were examined by SEM over a 0.5 mm×0.5 mm grid, which was spatially correlated to the measured flux distributions. In this manner, we were able to obtain, in a single ion beam exposure, the flux dependence of the observed surface morphology changes at each of the two energies. At 218 eV, for fluxes below 1.5×1016/cm2s, ordered surface structures are observed, with great grain-to-grain variability, together with blisters and pinholes, while above this flux value, individual grain characteristics disappear, and nano-fuzz growth is observed. At 2 keV, very similar surface morphologies are observed, but the flux threshold for nano-fuzz formation has almost doubled, to 2.5 -- 3×1016/cm2s. Possible reasons for this increase will be discussed. Research sponsored by the LDRD Program of ORNL, managed by UT Battelle, LLC, for the US DOE.

  18. Photo-Double Ionization: Threshold Law and Low-Energy Behavior

    NASA Technical Reports Server (NTRS)

    Bhatia, A. K.; Temkin, A.

    2007-01-01

    The threshold law for photoejection of two electrons from atoms (PDI) is derived from a modification of the Coulomb-dipole (C-D) theory. The C-D theory applies to two-electron ejection from negative ions (photo-double detachment:PDD). The modification consists of correctly accounting for the fact that in PDI that the two escaping electrons see a Coulomb field, asymptotically no matter what their relative distances from the residual ion are. We find in the contralinear spherically symmetric model that the analytic threshold law Q(E), i.e. the yield of residual ions, to be Q Integral of (E) varies as E + (C(sub w) E(sup gamma W)) +CE(sup 5/4) sin [1/2 ln E + phi]/ln(E). The first and third terms are beyond the Wannier law. Our threshold law can only be rigorously justified for residual energies <= 10(exp -3) eV. Nevertheless in the present experimental range (0.1 - 4 eV), the form, even without the second term, can be fitted to experimental results of PDI for He, Li, and Be, in contrast to the Wannier law which has a larger deviation from the data for Li and Be.

  19. Photo-Double Ionization: Threshold Law and Low-Energy Behavior

    NASA Technical Reports Server (NTRS)

    Bhatia, Anand

    2008-01-01

    The threshold law for photoejection of two electrons from atoms (PDI) is derived from a modification of the Coulomb-dipole (C-D) theory. The C-D theory applies to two-electron ejection from negative ions (photo-double detachment:PDD). The modification consists of correctly accounting for the fact that in PDI that the two escaping electrons see a Coulomb field, asymptotically no matter what their relative distances from the residual ion are. We find in the contralinear spherically symmetric model that the analytic threshold law Q(E),i. e. the yield of residual ions, to be Qf(E)approaches E + CwE(sup gamma(w)) + CE(sup 5/4)sin[1/2 ln(E + theta)]/ln(E). The first and third terms are beyond the Wannier law. Our threshold law can only be rigorously justified for residual energies less than or equal to 10(exp -3) eV. Nevertheless in the present experimental range (0.1 - 4 eV), the form, even without the second term, can be fitted to experimental results of PDI for He, Li, and Be, in contrast to the Wannier law which has a larger deviation from the data for Li and Be, for both of which the data show signs of modulation.

  20. Threshold quantum cryptography

    SciTech Connect

    Tokunaga, Yuuki [NTT Information Sharing Platform Laboratories, NTT Corporation, 1-1 Hikari-no-oka, Yokosuka, Kanagawa 239-0847 (Japan); Division of Materials Physics, Graduate School of Engineering Science, Osaka University, Toyonaka, Osaka 560-8531 (Japan); Okamoto, Tatsuaki [NTT Information Sharing Platform Laboratories, NTT Corporation, 1-1 Hikari-no-oka, Yokosuka, Kanagawa 239-0847 (Japan); Imoto, Nobuyuki [Division of Materials Physics, Graduate School of Engineering Science, Osaka University, Toyonaka, Osaka 560-8531 (Japan)

    2005-01-01

    We present the concept of threshold collaborative unitary transformation or threshold quantum cryptography, which is a kind of quantum version of threshold cryptography. Threshold quantum cryptography states that classical shared secrets are distributed to several parties and a subset of them, whose number is greater than a threshold, collaborates to compute a quantum cryptographic function, while keeping each share secretly inside each party. The shared secrets are reusable if no cheating is detected. As a concrete example of this concept, we show a distributed protocol (with threshold) of conjugate coding.

  1. Threshold photoelectron studies of isoxazole over the energy range 9.9-30 eV

    NASA Astrophysics Data System (ADS)

    Dampc, Marcin; Mielewska, Brygida; Siggel-King, Michele R. F.; King, George C.; Sivaraman, Bhalamurugan; Ptasi?ska, Sylwia; Mason, Nigel; Zubek, Mariusz

    2010-02-01

    The threshold photoelectron spectrum of the isoxazole molecule, C 3H 3NO has been measured over the photon energy range 9.9-30 eV with the use of synchrotron radiation. In the 9.9-10.8 eV range, corresponding to photoionization from the highest occupied molecular orbital 3a?(? 3), seven well resolved vibrational series have been observed and their modes are tentatively assigned. A strong adiabatic ionization, with an energy of 11.132 ± 0.003 eV corresponding to the 2a?(? 2) band, has also been observed. This is followed by a single vibrational series of the ?C-H stretching mode. Photoelectron bands in the energy region 13-30 eV have also been identified, some for the first time.

  2. Energy Detection Based on Undecimated Discrete Wavelet Transform and Its Application in Magnetic Anomaly Detection

    PubMed Central

    Nie, Xinhua; Pan, Zhongming; Zhang, Dasha; Zhou, Han; Chen, Min; Zhang, Wenna

    2014-01-01

    Magnetic anomaly detection (MAD) is a passive approach for detection of a ferromagnetic target, and its performance is often limited by external noises. In consideration of one major noise source is the fractal noise (or called 1/f noise) with a power spectral density of 1/fa (0energy detection method based on undecimated discrete wavelet transform (UDWT) is proposed in this paper. Firstly, the foundations of magnetic anomaly detection and UDWT are introduced in brief, while a possible detection system based on giant magneto-impedance (GMI) magnetic sensor is also given out. Then our proposed energy detection based on UDWT is described in detail, and the probabilities of false alarm and detection for given the detection threshold in theory are presented. It is noticeable that no a priori assumptions regarding the ferromagnetic target or the magnetic noise probability are necessary for our method, and different from the discrete wavelet transform (DWT), the UDWT is shift invariant. Finally, some simulations are performed and the results show that the detection performance of our proposed detector is better than that of the conventional energy detector even utilized in the Gaussian white noise, especially when the spectral parameter ? is less than 1.0. In addition, a real-world experiment was done to demonstrate the advantages of the proposed method. PMID:25343484

  3. Unconstrained Respiration Measurement and Respiratory Arrest Detection Method by Dynamic Threshold in Transferring Patients by Stretchers

    NASA Astrophysics Data System (ADS)

    Kurihara, Yosuke; Watanabe, Kajiro; Kobayashi, Kazuyuki; Tanaka, Hiroshi

    General anesthesia used for surgical operations may cause unstable conditions of the patients after the operations, which could lead to respiratory arrests. Under such circumstances, nurses could fail in finding the change of the conditions, and other malpractices could also occur. It is highly possible that such malpractices may occur while transferring a patient from ICU to the room using a stretcher. Monitoring the change in the blood oxygen saturation concentration and other vital signs to detect a respiratory arrest is not easy when transferring a patient on a stretcher. Here we present several noise reduction system and algorithm to detect respiratory arrests in transferring a patient, based on the unconstrained air pressure method that the authors presented previously. As the result, when the acceleration level of the stretcher noise was 0.5G, the respiratory arrest detection ratio using this novel method was 65%, while that with the conventional method was 0%.

  4. Generalized minimum-error thresholding for unsupervised change detection from SAR amplitude imagery

    Microsoft Academic Search

    Gabriele Moser; Sebastiano B. Serpico

    2006-01-01

    The availability of synthetic aperture radar (SAR) data offers great potential for environmental monitoring due to the insensitiveness of SAR imagery to atmospheric and sunlight-illumination conditions. In addition, the short revisit time provided by future SAR-based missions will allow a huge amount of multitemporal SAR data to become systematically available for monitoring applications. In this paper, the problem of detecting

  5. Acetic Acid Detection Threshold in Synthetic Wine Samples of a Portable Electronic Nose

    PubMed Central

    Macías, Miguel Macías; Manso, Antonio García; Orellana, Carlos Javier García; Velasco, Horacio Manuel González; Caballero, Ramón Gallardo; Chamizo, Juan Carlos Peguero

    2013-01-01

    Wine quality is related to its intrinsic visual, taste, or aroma characteristics and is reflected in the price paid for that wine. One of the most important wine faults is the excessive concentration of acetic acid which can cause a wine to take on vinegar aromas and reduce its varietal character. Thereby it is very important for the wine industry to have methods, like electronic noses, for real-time monitoring the excessive concentration of acetic acid in wines. However, aroma characterization of alcoholic beverages with sensor array electronic noses is a difficult challenge due to the masking effect of ethanol. In this work, in order to detect the presence of acetic acid in synthetic wine samples (aqueous ethanol solution at 10% v/v) we use a detection unit which consists of a commercial electronic nose and a HSS32 auto sampler, in combination with a neural network classifier (MLP). To find the characteristic vector representative of the sample that we want to classify, first we select the sensors, and the section of the sensors response curves, where the probability of detecting the presence of acetic acid will be higher, and then we apply Principal Component Analysis (PCA) such that each sensor response curve is represented by the coefficients of its first principal components. Results show that the PEN3 electronic nose is able to detect and discriminate wine samples doped with acetic acid in concentrations equal or greater than 2 g/L. PMID:23262483

  6. Radiation Damage in Ge and Si Detected by Carrier Lifetime Changes: Damage Thresholds

    Microsoft Academic Search

    J. J. Loferski; P. Rappaport

    1958-01-01

    Minority carrier lifetime, tau, in semiconductors is shown to be more sensitive, by a factor of 104, to radiation-induced defects than the conductivity. Thus, in some cases, the introduction of as few as 1010 defects per cm3 can be detected by its effect on tau. Both direct measurements of tau, and measurements of dependent parameters (such as the photovoltaic effect

  7. Dynamics of strangeness production in heavy-ion collisions near threshold energies

    E-print Network

    Zhao-Qing Feng; Gen-Ming Jin

    2010-10-13

    Within the framework of the improved isospin dependent quantum molecular dynamics (ImIQMD) model, the dynamics of strangeness (K$^{0,+}$, $\\Lambda$ and $\\Sigma^{-,0,+}$) production in heavy-ion collisions near threshold energies is investigated systematically, in which the strange particles are considered to be mainly produced by the inelastic collisions of baryon-baryon and pion-baryon. The collisions in the region of supra-saturation densities of the dense baryonic matter formed in heavy-ion collisions dominate the yields of strangeness production. The total multiplicities as functions of incident energies and collision centralities are calculated with the Skyrme parameter SLy6. The excitation function of strangeness production is analyzed and also compared with the KaoS data for the K$^{+}$ production in the reactions $^{12}$C+$^{12}$C and $^{197}$Au+$^{197}$Au.

  8. {phi}-Meson Photoproduction with Linearly Polarized Photons at Threshold Energies

    SciTech Connect

    Salamanca, Julian; Cole, Philip L. [Idaho State University, Dept. of Physics, Pocatello, Idaho 83209 (United States)

    2007-10-26

    The observables provided by linearly-polarized photons are of interest in delineating the contributions of the various hadronic processes giving rise to vector meson photoproduction. In particular, we describe how {phi}-meson production affords an incisive tool for exploring the nature of the parity exchange at threshold energies, the strangeness content of proton, as well as extracting signatures for the violation of Okubo-Zweig-Iizuka observation (OZI rule). Our goal is to study the {gamma}-vectorp{yields}{phi}p reaction, with {phi}{yields}K{sup +}K{sup -}, in the photon energy range of 1.7 to 2.1 GeV by using the Coherent Linear Bremsstrahlung Facility in Hall B of Jefferson Laboratory, Newport News, VA. The data were collected during the g8b run in the summer of 2005.

  9. phi-Meson Photoproduction with Linearly Polarized Photons at Threshold Energies

    SciTech Connect

    Julian Salamanca; Philip L. Cole

    2007-10-01

    The observables provided by linearly-polarized photons are of interest in delineating the contributions of the various hadronic processes giving rise to vector meson photoproduction. In particular, we describe how phi-meson production affords an incisive tool for exploring the nature of the parity exchange at threshold energies, the strangeness content of proton, as well as extracting signatures for the violation of Okubo-Zweig-Iizuka observation (OZI rule). Our goal is to study the gamma-vector p-->phip reaction, with phi-->K+K?, in the photon energy range of 1.7 to 2.1 GeV by using the Coherent Linear Bremsstrahlung Facility in Hall B of Jefferson Laboratory, Newport News, VA. The data were collected during the g8b run in the summer of 2005.

  10. Dynamics of strangeness production in heavy-ion collisions near threshold energies

    SciTech Connect

    Feng Zhaoqing; Jin Genming [Institute of Modern Physics, Chinese Academy of Sciences, Lanzhou 730000 (China)

    2010-11-15

    Within the framework of the improved isospin-dependent quantum molecular dynamics (ImIQMD) model, the dynamics of strangeness (K{sup 0,+}, {Lambda}, and {Sigma}{sup -,0,+}) production in heavy-ion collisions near threshold energies is investigated systematically, with the strange particles considered to be produced mainly by inelastic collisions of baryon-baryon and pion-baryon. Collisions in the region of suprasaturation densities of the dense baryonic matter formed in heavy-ion collisions dominate the yields of strangeness production. Total multiplicities as functions of incident energies and collision centralities are calculated with the Skyrme parameter SLy6. The excitation function of strangeness production is analyzed and also compared with the KaoS data for K{sup +} production in the reactions {sup 12}C+{sup 12}C and {sup 197}Au+{sup 197}Au.

  11. Electron-impact ionization of helium clusters close to the threshold: appearance energies.

    PubMed

    Denifl, S; Stano, M; Stamatovic, A; Scheier, P; Märk, T D

    2006-02-01

    We have investigated the ionization threshold behavior of small helium cluster ions (cluster size n=2-10) formed via electron-impact ionization of neutral helium droplets and derive appearance energies for mass-selected cluster ions using a nonlinear least-square-fitting procedure. Moreover, we report magic numbers in the mass spectrum observed at the electron energy of 70 eV. The apparatus used for the present measurements is a hemispherical electron monochromator combined with a quadrupole mass spectrometer. Our experiment demonstrates that helium clusters are not only exclusively formed via direct ionization above the atomic ionization potential but also indirectly via autoionizing Rydberg states. The present results are compared with previous electron-impact and photoionization results. PMID:16468882

  12. Dynamics of strangeness production in heavy-ion collisions near threshold energies

    NASA Astrophysics Data System (ADS)

    Feng, Zhao-Qing; Jin, Gen-Ming

    2010-11-01

    Within the framework of the improved isospin-dependent quantum molecular dynamics (ImIQMD) model, the dynamics of strangeness (K0,+, ?, and ?-,0,+) production in heavy-ion collisions near threshold energies is investigated systematically, with the strange particles considered to be produced mainly by inelastic collisions of baryon-baryon and pion-baryon. Collisions in the region of suprasaturation densities of the dense baryonic matter formed in heavy-ion collisions dominate the yields of strangeness production. Total multiplicities as functions of incident energies and collision centralities are calculated with the Skyrme parameter SLy6. The excitation function of strangeness production is analyzed and also compared with the KaoS data for K+ production in the reactions C12+C12 and Au197+Au197.

  13. Detection efficiency enhancement of single-photon detector at 1.55-?m by using of single photons lock-in and optimal threshold

    NASA Astrophysics Data System (ADS)

    Wang, Xiaobo; Zhang, Guofeng; Chen, Ruiyun; Gao, Yan; Xiao, Liantuan; Jia, Suotang

    2012-09-01

    The detection efficiency considerations are often the true determining factor as to whether a sensitive measurement is feasible. We demonstrate a robust method of single photons lock-in to enhance the detection efficiency of InGaAs single-photon avalanche diodes at 1.55-?m wavelength and suppressing background noise. With the optimal threshold for discrimination, the detection efficiency is achieved to 1.87 times bigger than that of the conventional photon counting method.

  14. Infrared image dim small target detection based on double energy accumulation

    NASA Astrophysics Data System (ADS)

    Sun, Yuqiu; Zheng, Sheng; Tian, Jinwen; Liu, Jian

    2005-11-01

    Detection of dim moving small targets at low signal noise ratio is a very important issue and difficult problem in infrared searching and tracking system. Based on analysis of the character of infrared images, a new double energy accumulating method is proposed. Firstly, images are denoised by wavelet transformation with soft threshold. Then, object motion area is detected according to difference images and the target intensity is well enhanced by accumulating energy two times with addition and product operation. Finally, target candidates are separated from background by thresholding process with the selected threshold. Computer experiments are carried out with an infrared image sequence and the experimental results illustrate that the proposed method is effective and efficient.

  15. Energy Detection Based Estimation of Channel Occupancy Rate with Adaptive Noise Estimation

    NASA Astrophysics Data System (ADS)

    Lehtomäki, Janne J.; Vuohtoniemi, Risto; Umebayashi, Kenta; Mäkelä, Juha-Pekka

    Recently, there has been growing interest in opportunistically utilizing the 2.4GHz ISM-band. Numerous spectrum occupancy measurements covering the ISM-band have been performed to analyze the spectrum usage. However, in these campaigns the verification of the correctness of the obtained occupancy values for the highly dynamic ISM-band has not been presented. In this paper, we propose and verify channel occupancy rate (COR) estimation utilizing energy detection mechanism with a novel adaptive energy detection threshold setting method. The results are compared with the true reference COR values. Several different types of verification measurements showed that our setup can estimate the COR values of 802.11 traffic well, with negligible overestimation. The results from real-time real-life measurements also confirm that the proposed adaptive threshold setting method enables accurate thresholds even in the situations where multiple interferers are present in the received signal.

  16. Displacement Threshold Energy and Recovery in an Al-Ti Nanolayered System with Intrinsic Point Defect Partitioning

    SciTech Connect

    Gerboth, Matthew D.; Setyawan, Wahyu; Henager, Charles H.

    2014-01-07

    A method is established and validated using molecular dynamics (MD) to determine the displacement threshold energies as Ed in nanolayered, multilayered systems of dissimilar metals. The method is applied to specifically oriented nanolayered films of Al-Ti where the crystal structure and interface orientations are varied in atomic models and Ed is calculated. Methods for defect detection are developed and discussed based on prior research in the literature and based on specific crystallographic directions available in the nanolayered systems. These are compared and contrasted to similar calculations in corresponding bulk materials, including fcc Al, fcc Ti, hcp Al, and hcp Ti. In all cases, the calculated Ed in the multilayers are intermediate to the corresponding bulk values but exhibit some important directionality. In the nanolayer, defect detection demonstrated systematic differences in the behavior of Ed in each layer. Importantly, collision cascade damage exhibits significant defect partitioning within the Al and Ti layers that is hypothesized to be an intrinsic property of dissimilar nanolayered systems. This type of partitioning could be partly responsible for observed asymmetric radiation damage responses in many multilayered systems. In addition, a pseudo-random direction was introduced to approximate the average Ed without performing numerous simulations with random directions.

  17. Calculation of pair production by photons of energies near threshold on atoms

    NASA Astrophysics Data System (ADS)

    Tseng, H. K.

    1994-07-01

    We calculated numerically in a relativistic partial-wave formulation the positron energy spectra of pair-production ?(E+) in the field of atoms with atomic number Z=1, 6, 13, and 82 for photons of energies near threshold, k=2.001, 2.01, and 2.10 mec2, where E+ is the positron energy. Our results indicate that in this low-photon-energy region, the atomic-electron screening effect increases as Z increases, k decreases, and E+ decreases. The ratio of screened to point-Coulomb cross sections ?(E+) varies from 0.985 to 1.69×104. When the screening effect is important, it increases the cross section ?(E+). Our results also indicate that the approximate treatment of screening through energy-shift screening theory becomes inadequate when the screening effect is very important. The approximate treatment of screening through the corrected-effective normalization screening theory works fine in this low-photon-energy region, except for the case with Z=6, k=2.001mec2, and E+=1.0001mec2, where the screening effect is not a normalization effect.

  18. Effects of pion potential and nuclear symmetry energy on the ?-/?+ ratio in heavy-ion collisions at beam energies around the pion production threshold

    NASA Astrophysics Data System (ADS)

    Guo, Wen-Mei; Yong, Gao-Chan; Liu, Hang; Zuo, Wei

    2015-05-01

    Within the framework of the isospin-dependent Boltzmann-Uehling-Uhlenbeck (IBUU) transport model, we studied the effects of the pion potential and the symmetry energy on the pion production in central 197Au+197Au collisions around the pion production threshold. It is found that the pion potential has opposite effects on the value of the ?-/?+ ratio at low and high pion energies. The effect of the pion potential on the total ?-/?+ ratio becomes larger in heavy-ion collisions at beam energies below the pion production threshold. At beam energies below the pion production threshold, with the pion potential, the effect of the symmetry energy on the ?-/?+ ratio becomes smaller compared with that above the pion production threshold.

  19. Target tracking using energy based detections

    Microsoft Academic Search

    Xuezhi Wang; D. Musicki

    2007-01-01

    Energy based detection measures sensor received signal strength (RSS) transmitted from a target. In this paper, we propose a new approach for estimating a moving target trajectory over a sensor field via energy based detections as an alternative to trilateration positioning or nonlinear estimation. In 2D case, possible target locations described by a RSS ratio from two sensors are approximated

  20. Toward perpetual wireless networks: Opportunistic large arrays with transmission thresholds and energy harvesting

    NASA Astrophysics Data System (ADS)

    Kailas, Aravind

    Solving the key issue of sustainability of battery-powered sensors continues to attract significant research attention. The prevailing theme of this research is to address this concern using energy-efficient protocols based on a form of simple cooperative transmission (CT) called the opportunistic large arrays (OLAs), and intelligent exploitation of energy harvesting and hybrid energy storage systems (HESSs). The two key contributions of this research, namely, OLA with transmission threshold (OLA-T) and alternating OLA-T (A-OLA-T), offer an signal-to-noise ratio (SNR) advantage (i.e., benefits of diversity and array (power) gains) in a multi-path fading environment, thereby reducing transmit powers or extending range. Because these protocols do not address nodes individually, the network overhead remains constant for high density networks or nodes with mobility. During broadcasting across energy-constrained networks, while OLA-T saves energy by limiting node participation within a single broadcast, A-OLA-T optimizes over multiple broadcasts and drains the nodes in an equitable fashion. A major bottleneck for network sustainability is the ability of a rechargeable battery (RB) to store energy, which is limited by the number of charge-discharge cycles. Energy harvesting using a HESS that comprises a RB and a supercapacitor (SC) will minimize the RB usage, thereby preserving the charge-discharge cycles. Studying the HESS is important, rather than the SC-alone because while an SC with harvested energy may be sufficient for routine monitoring, if there is an alert, the RB could be used as necessary to support the heavier reporting requirements. Therefore, another key contribution of this research is the design and analysis of a novel routing metric called communications using HESS (CHESS), which extends the RB-life by relaying exclusively with SC energy.

  1. Detectability and appraisal thresholds of split pulse signals for the MemoPatch™ device, an electronic skin patch intended to deliver tactile medication reminder signals (study TS-104).

    PubMed

    Abraham, Ivo; De Geest, Wim; De Geest, Jan; De Troy, Elke; MacDonald, Karen

    2013-01-01

    Patient non-adherence to prescribed medication regimens is a significant problem and affects clinical treatment outcomes. The MemoPatch™ medical device, currently in development, is an electronic skin patch intended to deliver tactile medication reminder signals. Fifty volunteers completed a laboratory experiment that evaluated the detectability and appraisal thresholds of five split signals; specifically, the current thresholds (in mA) at which a signal was detected (threshold T1), was considered sufficiently detectable to serve as a reminder signal (threshold T2), and became too strong as a reminder signal (threshold T3). Signals were selected under consideration of three data points: T1Max and T2Max (defined as, resp., the maximum current observed at T1 and T2) and T3Pct90 (the T3 current at the 90(th) percentile). A signal was considered to be useable in future versions of the MemoPatch™ device if it met the constraint that (T3Pct90-T2Max) should not be negative. One signal met the constraint requirement as its T3Pct90-T2Max=0.96mA. PMID:24109837

  2. A differentially amplified motion in the ear for near-threshold sound detection

    PubMed Central

    Chen, Fangyi; Zha, Dingjun; Fridberger, Anders; Zheng, Jiefu; Choudhury, Niloy; Jacques, Steven L.; Wang, Ruikang K.; Shi, Xiaorui; Nuttall, Alfred L.

    2011-01-01

    The ear is a remarkably sensitive pressure fluctuation detector. In guinea pigs, behavioral measurements indicate a minimum detectable sound pressure of ~20 ?Pa at 16 kHz. Such faint sounds produce 0.1 nm basilar membrane displacements, a distance smaller than conformational transitions in ion channels. It seems that noise within the auditory system would swamp such tiny motions, making weak sounds imperceptible. Here, a new mechanism contributing to a resolution of this problem is proposed and validated through direct measurement. We hypothesize that vibration at the apical end of hair cells is enhanced compared to the commonly measured basilar membrane side. Using in vivo optical coherence tomography, we demonstrated that apical-side vibrations peak at a higher frequency, had different timing, and were enhanced compared to the basilar membrane. These effects depend nonlinearly on the stimulus level. The timing difference and enhancement are important for explaining how the noise problem is circumvented. PMID:21602821

  3. Proton and Electron Threshold Energy Measurements for Extravehicular Activity Space Suits. Chapter 2

    NASA Technical Reports Server (NTRS)

    Moyers, M. F.; Nelson, G. D.; Saganti, P. B.

    2003-01-01

    Construction of ISS will require more than 1000 hours of EVA. Outside of ISS during EVA, astronauts and cosmonauts are likely to be exposed to a large fluence of electrons and protons. Development of radiation protection guidelines requires the determination of the minimum energy of electrons and protons that penetrate the suits at various locations. Measurements of the water-equivalent thickness of both US. and Russian EVA suits were obtained by performing CT scans. Specific regions of interest of the suits were further evaluated using a differential range shift technique. This technique involved measuring thickness ionization curves for 6-MeV electron and 155-MeV proton beams with ionization chambers using a constant source-to-detector distance. The thicknesses were obtained by stacking polystyrene slabs immediately upstream of the detector. The thicknesses of the 50% ionizations relative to the maximum ionizations were determined. The detectors were then placed within the suit and the stack thickness adjusted until the 50% ionization was reestablished. The difference in thickness between the 50% thicknesses was then used with standard range-energy tables to determine the threshold energy for penetration. This report provides a detailed description of the experimental arrangement and results.

  4. Dual energy computed tomography for explosive detection

    Microsoft Academic Search

    Zhengrong Ying; Ram Naidu; Carl R. Crawford

    2006-01-01

    Single energy computed tomography (CT) scanners use measurements of densities to detect explosives in luggage. It is desirable to apply dual energy techniques to these CT scanners to obtain atomic number measurements to reduce false alarm rates. However, the direct application of existing dual energy techniques has practical problems, such as, approximation errors and lack of boundary constraints in dual

  5. Modifications of the pion-production threshold in the nuclear medium in heavy ion collisions and the nuclear symmetry energy

    NASA Astrophysics Data System (ADS)

    Song, Taesoo; Ko, Che Ming

    2015-01-01

    Using the relativistic Vlasov-Uehling-Uhlenbeck (RVUU) equation based on mean fields from the nonlinear relativistic NL? and NL? ? models, which have same nuclear equation of state and symmetry energy but different symmetry energy slope parameters, we study the effect of medium modification of the pion-production threshold on the total pion yield and the ?-/?+ ratio in Au+Au collisions. We find that the in-medium threshold effect enhances both the total pion yield and the ?-/?+ ratio, compared to those without this effect. Furthermore, including the medium modification of the pion-production threshold leads to a larger ?-/?+ ratio for the NL? ? model with a larger symmetry energy parameter than the NL? model with a smaller symmetry energy parameter, opposite to that found without the in-medium threshold effect. To reproduce the total pion yield measured by the FOPI Collaboration, we introduce a density-dependent cross section for ? baryon production from nucleon-nucleon collisions, which suppresses the total pion yield but hardly changes the ?-/?+ ratio. Because of the small difference in the stiffness of their symmetry energies, the ?-/?+ ratios obtained from both the NL? and NL? ? models are consistent with the FOPI data within the experimental errors.

  6. A comparative analysis of a fixed thresholding vs. a classification tree approach for operational burn scar detection and mapping

    NASA Astrophysics Data System (ADS)

    Kontoes, C. C.; Poilvé, H.; Florsch, G.; Keramitsoglou, I.; Paralikidis, S.

    2009-10-01

    The scope of this paper is to demonstrate, evaluate and compare two burn scar mapping (BSM) approaches developed and applied operationally in the framework of the RISK-EOS service element project within the Global Monitoring for Environment and Security (GMES) program funded by ESA ( http://www.risk-eos.com). The first method is the BSM_NOA, a fixed thresholding method using a set of specifically designed and combined image enhancements, whilst the second one is the BSM_ITF, a decision tree classification approach based on a wide range of biophysical parameters. The two methods were deployed and compared in the framework of operational mapping conditions set by RISK-EOS standards, based either on sets of uni- or multi-temporal satellite images acquired by Landsat 5 TM and SPOT 4 HRV. The evaluation of the performance of the two methods showed that either in uni- or multi-temporal acquisition mode, the two methods reach high detection capability rates ranging from 80% to 91%. At the same time, the minimum burnt area detected was of 0.9-1.0 ha, despite the coarser spatial resolution of Landsat 5 TM sensor. Among the advantages of the satellite-based approaches compared to conventional burn scar mapping, are cost-efficiency, repeatability, flexibility, and high spatial and thematic accuracy from local to country level. Following the catastrophic fire season of 2007, burn scar maps were generated using BSM_NOA for the entirety of Greece and BSM_ITF for south France in the framework of the RISK-EOS/GMES Services Element project.

  7. Local energy pattern for texture classification using self-adaptive quantization thresholds.

    PubMed

    Zhang, Jun; Liang, Jimin; Zhao, Heng

    2013-01-01

    Local energy pattern, a statistical histogram-based representation, is proposed for texture classification. First, we use normalized local-oriented energies to generate local feature vectors, which describe the local structures distinctively and are less sensitive to imaging conditions. Then, each local feature vector is quantized by self-adaptive quantization thresholds determined in the learning stage using histogram specification, and the quantized local feature vector is transformed to a number by N-nary coding, which helps to preserve more structure information during vector quantization. Finally, the frequency histogram is used as the representation feature. The performance is benchmarked by material categorization on KTH-TIPS and KTH-TIPS2-a databases. Our method is compared with typical statistical approaches, such as basic image features, local binary pattern (LBP), local ternary pattern, completed LBP, Weber local descriptor, and VZ algorithms (VZ-MR8 and VZ-Joint). The results show that our method is superior to other methods on the KTH-TIPS2-a database, and achieving competitive performance on the KTH-TIPS database. Furthermore, we extend the representation from static image to dynamic texture, and achieve favorable recognition results on the University of California at Los Angeles (UCLA) dynamic texture database. PMID:22910113

  8. A Transregional Model for Near-Threshold Circuits with Application to Minimum-Energy Operation

    E-print Network

    Harris, David Money

    such as implantable medical devices, wireless sensor networks, and RFID tags, researchers are increasingly interested model for Ion that is valid in the near-threshold region. Based on the ON-current, a propagation delay in operating CMOS circuits below or near the device threshold voltage (Vt) [1]. Furthermore, throughput

  9. Extended performance gas Cherenkov detector for gamma-ray detection in high-energy density experimentsa)

    NASA Astrophysics Data System (ADS)

    Herrmann, H. W.; Kim, Y. H.; Young, C. S.; Fatherley, V. E.; Lopez, F. E.; Oertel, J. A.; Malone, R. M.; Rubery, M. S.; Horsfield, C. J.; Stoeffl, W.; Zylstra, A. B.; Shmayda, W. T.; Batha, S. H.

    2014-11-01

    A new Gas Cherenkov Detector (GCD) with low-energy threshold and high sensitivity, currently known as Super GCD (or GCD-3 at OMEGA), is being developed for use at the OMEGA Laser Facility and the National Ignition Facility (NIF). Super GCD is designed to be pressurized to ?400 psi (absolute) and uses all metal seals to allow the use of fluorinated gases inside the target chamber. This will allow the gamma energy threshold to be run as low at 1.8 MeV with 400 psi (absolute) of C2F6, opening up a new portion of the gamma ray spectrum. Super GCD operating at 20 cm from TCC will be ˜400 × more efficient at detecting DT fusion gammas at 16.7 MeV than the Gamma Reaction History diagnostic at NIF (GRH-6m) when operated at their minimum thresholds.

  10. Tunnel effect wave energy detection

    NASA Technical Reports Server (NTRS)

    Kaiser, William J. (Inventor); Waltman, Steven B. (Inventor); Kenny, Thomas W. (Inventor)

    1995-01-01

    Methods and apparatus for measuring gravitational and inertial forces, magnetic fields, or wave or radiant energy acting on an object or fluid in space provide an electric tunneling current through a gap between an electrode and that object or fluid in space and vary that gap with any selected one of such forces, magnetic fields, or wave or radiant energy acting on that object or fluid. These methods and apparatus sense a corresponding variation in an electric property of that gap and determine the latter force, magnetic fields, or wave or radiant energy in response to that corresponding variation, and thereby sense or measure such parameters as acceleration, position, particle mass, velocity, magnetic field strength, presence or direction, or wave or radiant energy intensity, presence or direction.

  11. Thresholds for igniting exothermic reactions in Al/Ni multilayers using pulses of electrical, mechanical, and thermal energy

    NASA Astrophysics Data System (ADS)

    Fritz, Gregory M.; Spey, Stephen J.; Grapes, Michael D.; Weihs, Timothy P.

    2013-01-01

    We use pulses of electrical, mechanical, and thermal energy to determine the ignition thresholds of self-propagating reactions in Al/(Ni-7 V) and Al/Inconel multilayers. The energy density and power density required to initiate reactions in a Al/(Ni-7 V) foil with a 50 nm bilayer is compared for all three techniques to demonstrate the importance of heat loss on ignition thresholds and its dependence on the test volume and the surrounding thermal resistance. In addition, ignition is shown to occur at temperatures as low as 232 °C when heat losses are very small suggesting that ignition can be controlled by atomic mixing in the solid state. The experiments demonstrate that the ignition threshold drops with increasing ignition volume, and it rises with increasing bilayer spacing and with increasing intermixed thickness. These trends are also supported by an analytical model we derive to predict the effects of ignition volume, multilayer microstructure, and physical properties on the ignition threshold. We calculate an activation energy of 77.3 ± 1.3 kJ/mol for solid state mixing based on measured ignition temperatures.

  12. ASTROPHYSICS AND COSMOLOGY RELATED TO PARTICLES AND NUCLEI: Ultra-high energy cosmic rays threshold in Randers-Finsler space

    NASA Astrophysics Data System (ADS)

    Chang, Zhe; Li, Xin

    2009-08-01

    Kinematics in Finsler space is used to study the propagation of ultra high energy cosmic rays particles through the cosmic microwave background radiation. We find that the GZK threshold is lifted dramatically in Randers-Finsler space. A tiny deformation of spacetime from Minkowskian to Finslerian allows more ultra-high energy cosmic rays particles to arrive at the earth. It is suggested that the lower bound of particle mass is related with the negative second invariant speed in Randers-Finsler space.

  13. Threshold energy for plasma etching of high-k dielectric HfO2 films in BCl3-containing plasmas

    Microsoft Academic Search

    Yoshinori Ueda; Keisuke Nakamura; Hiroaki Kiyokami; Hiroaki Ohta; Koji Eriguchi; Kouichi Ono

    2008-01-01

    Plasma etching of high dielectric constant (k) materials is indispensable for fabricating of future high performance ULSIs. This paper presents the dependence of HfO2 etch rate on incident ion energy onto a wafer stage, with emphasis being placed on the threshold energy for HfO2 etching in BCl3-containing plasmas. Experiments were performed in both an electron cyclotron resonance (ECR) and an

  14. Radiative electroweak symmetry breaking in the minimal supersymmetric standard model and low energy thresholds

    SciTech Connect

    Dedes, A. [Division of Theoretical Physics, University of Ioannina, Ioannina, GR-45110 (Greece)] [Division of Theoretical Physics, University of Ioannina, Ioannina, GR-45110 (Greece); Lahanas, A.B. [University of Athens, Physics Department, Nuclear and Particle Physics Section, Ilissia, GR-15771 Athens (Greece)] [University of Athens, Physics Department, Nuclear and Particle Physics Section, Ilissia, GR-15771 Athens (Greece); Tamvakis, K. [Division of Theoretical Physics, University of Ioannina, Ioannina, GR-45110 (Greece)] [Division of Theoretical Physics, University of Ioannina, Ioannina, GR-45110 (Greece)

    1996-04-01

    We study radiative electroweak symmetry breaking in the minimal supersymmetric standard model (MSSM). We employ the two-loop renormalization group equations for running masses and couplings taking into account sparticle threshold effects. The decoupling of each particle below its threshold is realized by a step function in all one-loop renormalization group equations. This program requires the calculation of all wave function, vertex, and mass renormalizations for all particles involved. Adapting our numerical routines to take care of the succesive decoupling of each particle below its threshold, we compute the mass spectrum of sparticles and Higgs bosons consistent with the existing experimental constraints. The effect of the threshold corrections is in general of the same order of magnitude as the two-loop contributions with the exception of the heavy Higgs bosons and those neutralino and chargino states that are nearly Higgsinos for large values of the parameter {mu}. {copyright} {ital 1996 The American Physical Society.}

  15. Determination of a chemisorption bond strength by direct measurement of the threshold energy for collision-induced desorption: Ammonia on Pt{111}

    NASA Astrophysics Data System (ADS)

    Szulczewski, Gregory; Levis, Robert J.

    1994-12-01

    Direct measurement of the threshold desorption energy for collision-induced desorption is used to determine a chemisorption bond energy. In this experiment the absolute cross section for desorption is measured using x-ray photoelectron spectroscopy as a function of the impact energy between a translationally energetic Ar atom and an ammonia molecule chemisorbed to a Pt{111} single crystal. For this adsorbate-surface system the threshold desorption energy is found to be 1.8±0.17 eV and is independent of the angle of incidence of the Ar beam. Using a classical energy transfer mechanism this threshold energy is found to correspond to a bond energy of 1.4±0.13 eV. This represents an upper limit for the bond strength assuming maximum energy transfer between Ar and NH3 and no internal excitation of the adsorbate at the desorption threshold.

  16. HIGH ENERGY POLARIZATION OF BLAZARS: DETECTION PROSPECTS

    SciTech Connect

    Chakraborty, N. [Max-Planck-Institut für Kernphysik, Saupfercheckweg 1, D-69117 Heidelberg (Germany); Pavlidou, V. [Department of Physics, University of Crete, 71003 Heraklion (Greece); Fields, B. D. [Department of Astronomy and Department of Physics, University of Illinois, Urbana, IL 61801 (United States)

    2015-01-01

    Emission from blazar jets in the ultraviolet, optical, and infrared is polarized. If these low-energy photons were inverse-Compton scattered, the upscattered high-energy photons retain a fraction of the polarization. Current and future X-ray and gamma-ray polarimeters such as INTEGRAL-SPI, PoGOLITE, X-Calibur, Gamma-Ray Burst Polarimeter, GEMS-like missions, ASTRO-H, and POLARIX have the potential to discover polarized X-rays and gamma-rays from blazar jets for the first time. Detection of such polarization will open a qualitatively new window into high-energy blazar emission; actual measurements of polarization degree and angle will quantitatively test theories of jet emission mechanisms. We examine the detection prospects of blazars by these polarimetry missions using examples of 3C 279, PKS 1510-089, and 3C 454.3, bright sources with relatively high degrees of low-energy polarization. We conclude that while balloon polarimeters will be challenged to detect blazars within reasonable observational times (with X-Calibur offering the most promising prospects), space-based missions should detect the brightest blazars for polarization fractions down to a few percent. Typical flaring activity of blazars could boost the overall number of polarimetric detections by nearly a factor of five to six purely accounting for flux increase of the brightest of the comprehensive, all-sky, Fermi-LAT blazar distribution. The instantaneous increase in the number of detections is approximately a factor of two, assuming a duty cycle of 20% for every source. The detectability of particular blazars may be reduced if variations in the flux and polarization fraction are anticorrelated. Simultaneous use of variability and polarization trends could guide the selection of blazars for high-energy polarimetric observations.

  17. Low-frequency approximation for above-threshold ionization by a laser pulse: Low-energy forward rescattering

    NASA Astrophysics Data System (ADS)

    Miloševi?, D. B.

    2014-12-01

    In the context of the development of new sources of strong laser pulses in the mid-infrared region new nonperturbative methods for analysis of strong-laser-field induced or assisted atomic and molecular processes are welcome. We formulate such a theory of above-threshold ionization by a strong low-frequency laser pulse. We call this theory the low-frequency approximation (LFA). A detailed derivation of the LFA, both for short and long laser pulses, is given. As an example the LFA is applied to the analysis of recently discovered low-energy structures in the above-threshold ionization spectra of atoms ionized by long-wavelength laser pulses. It was found that these low-energy structures are caused by the forward soft recollision of the ionized electrons with the parent ion which is enhanced by the Coulomb effect.

  18. Measurement of inclusive radiative B-meson decays with a photon energy threshold of 1.7 GeV.

    PubMed

    Limosani, A; Aihara, H; Arinstein, K; Aushev, T; Bakich, A M; Balagura, V; Barberio, E; Bay, A; Belous, K; Bischofberger, M; Bondar, A; Bozek, A; Bracko, M; Browder, T E; Chang, P; Chao, Y; Chen, A; Cheon, B G; Choi, Y; Dalseno, J; Danilov, M; Drutskoy, A; Dungel, W; Eidelman, S; Goldenzweig, P; Golob, B; Ha, H; Hayashii, H; Hoshi, Y; Hou, W-S; Hyun, H J; Inami, K; Itoh, R; Iwasaki, Y; Julius, T; Kah, D H; Kim, H O; Kim, S K; Kim, Y I; Kim, Y J; Kinoshita, K; Ko, B R; Korpar, S; Kreps, M; Krizan, P; Krokovny, P; Kuhr, T; Kumar, R; Kwon, Y-J; Kyeong, S-H; Lesiak, T; Li, J; Liu, C; Liventsev, D; Louvot, R; Matyja, A; Miyabayashi, K; Miyata, H; Miyazaki, Y; Mizuk, R; Mori, T; Nakao, M; Nakazawa, H; Nishida, S; Nishimura, K; Nitoh, O; Nozaki, T; Ogawa, S; Ohshima, T; Okuno, S; Ozaki, H; Pakhlova, G; Park, C W; Park, H; Piilonen, L E; Rozanska, M; Sahoo, H; Sakai, Y; Schneider, O; Schümann, J; Schwanda, C; Schwartz, A J; Senyo, K; Sevior, M E; Shapkin, M; Shebalin, V; Shen, C P; Shiu, J-G; Singh, J B; Stanic, S; Staric, M; Sumisawa, K; Sumiyoshi, T; Suzuki, S; Taylor, G N; Teramoto, Y; Trabelsi, K; Tsuboyama, T; Uehara, S; Unno, Y; Uno, S; Urquijo, P; Ushiroda, Y; Varner, G; Varvell, K E; Vervink, K; Wang, C H; Wang, M-Z; Wang, P; Watanabe, Y; Wedd, R; Wicht, J; Won, E; Yabsley, B D; Yamamoto, H; Yamashita, Y; Zhang, Z P; Zivko, T; Zupanc, A

    2009-12-11

    Using 605 fb(-1) of data collected at the Upsilon(4S) resonance we present a measurement of the inclusive radiative B-meson decay channel, B-->X(s)gamma. For the lower photon energy thresholds of 1.7, 1.8, 1.9, and 2.0 GeV, as defined in the rest frame of the B meson, we measure the partial branching fraction and the mean and variance of the photon energy spectrum. At the 1.7 GeV threshold we obtain the partial branching fraction BF(B-->X(s)}gamma)=(3.45+/-0.15+/-0.40)x10(-4), where the errors are statistical and systematic. PMID:20366195

  19. Cross-matching: a modified cross-correlation underlying threshold energy model and match-based depth perception.

    PubMed

    Doi, Takahiro; Fujita, Ichiro

    2014-01-01

    Three-dimensional visual perception requires correct matching of images projected to the left and right eyes. The matching process is faced with an ambiguity: part of one eye's image can be matched to multiple parts of the other eye's image. This stereo correspondence problem is complicated for random-dot stereograms (RDSs), because dots with an identical appearance produce numerous potential matches. Despite such complexity, human subjects can perceive a coherent depth structure. A coherent solution to the correspondence problem does not exist for anticorrelated RDSs (aRDSs), in which luminance contrast is reversed in one eye. Neurons in the visual cortex reduce disparity selectivity for aRDSs progressively along the visual processing hierarchy. A disparity-energy model followed by threshold nonlinearity (threshold energy model) can account for this reduction, providing a possible mechanism for the neural matching process. However, the essential computation underlying the threshold energy model is not clear. Here, we propose that a nonlinear modification of cross-correlation, which we term "cross-matching," represents the essence of the threshold energy model. We placed half-wave rectification within the cross-correlation of the left-eye and right-eye images. The disparity tuning derived from cross-matching was attenuated for aRDSs. We simulated a psychometric curve as a function of graded anticorrelation (graded mixture of aRDS and normal RDS); this simulated curve reproduced the match-based psychometric function observed in human near/far discrimination. The dot density was 25% for both simulation and observation. We predicted that as the dot density increased, the performance for aRDSs should decrease below chance (i.e., reversed depth), and the level of anticorrelation that nullifies depth perception should also decrease. We suggest that cross-matching serves as a simple computation underlying the match-based disparity signals in stereoscopic depth perception. PMID:25360107

  20. Alternative Detection Methods for Highest Energy Neutrinos

    E-print Network

    Rolf Nahnhauer

    2004-11-26

    Several experimental techniques are currently under development, to measure the expected tiny fluxes of highest energy neutrinos above 10**18 eV. Projects in different stages of realisation are discussed here, which are based on optical and radio as well as acoustic detectors. For the detection of neutrino events in this energy range a combination of different detector concepts in one experiment seems to be most promising.

  1. Acetate Threshold Concentrations Suggest Varying Energy Requirements during Anaerobic Respiration by Anaeromyxobacter dehalogenans

    Microsoft Academic Search

    Qiang He; Robert A. Sanford

    2004-01-01

    Acetate threshold concentrations were determined under chlororespiring and Fe(III)-reducing conditions for Anaeromyxobacter dehalogenans strain 2CP-C. The acetate threshold concentrations measured were 69 4, 19 8, and <1 nM for chlororespiration, amorphous Fe(III) reduction, and Fe(III) citrate reduction, respectively. Residual G values of 75.4 kJ\\/mol of electrons for chlororespiration and 41.5 kJ\\/mol of electrons for amorphous Fe(III) reduction were calculated at

  2. Silicon Detectors for Low Energy Particle Detection

    E-print Network

    California at Berkeley, University of

    Silicon Detectors for Low Energy Particle Detection C.S. Tindall, N.P. Palaio, B.A. Ludewigt, S-7300 Abstract­ Silicon detectors with very thin entrance contacts have been fabricated for use in the IMPACT on the THEMIS mission. The silicon diode detectors were fabricated using a 200� thick phosphorous doped

  3. Energy detection of unknown deterministic signals

    Microsoft Academic Search

    H. Urkowitz

    1967-01-01

    By using Shannon's sampling formula, the problem of the detection of a deterministic signal in white Gaussian noise, by means of an energy-measuring device, reduces to the consideration of the sum of the squares of statistically independent Gaussian variates. When the signal is absent, the decision statistic has a central chi-square distribution with the number of degrees of freedom equal

  4. Energy sorghum biomass harvest thresholds and tillage effects on soil organic carbon and bulk density

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Bioenergy feedstock production systems face many challenges, among which is the lack of guidelines on sustainable biomass harvest thresholds, and tillage cropping systems that minimize the potential cumulative effects of fresh biomass harvesting equipment-induced soil compaction. We used the ALMANAC...

  5. Maintenance energy requirements of odor detection, explosive detection and human detection working dogs.

    PubMed

    Mullis, Rebecca A; Witzel, Angela L; Price, Joshua

    2015-01-01

    Despite their important role in security, little is known about the energy requirements of working dogs such as odor, explosive and human detection dogs. Previous researchers have evaluated the energy requirements of individual canine breeds as well as dogs in exercise roles such as sprint racing. This study is the first to evaluate the energy requirements of working dogs trained in odor, explosive and human detection. This retrospective study evaluated twenty adult dogs who maintained consistent body weights over a six month period. During this time, the average energy consumption was [Formula: see text] or two times the calculated resting energy requirement ([Formula: see text]). No statistical differences were found between breeds, age or sex, but a statistically significant association (p = 0.0033, R-square = 0.0854) was seen between the number of searches a dog performs and their energy requirement. Based on this study's population, it appears that working dogs have maintenance energy requirements similar to the 1974 National Research Council's (NRC) maintenance energy requirement of [Formula: see text] (National Research Council (NRC), 1974) and the [Formula: see text] reported for young laboratory beagles (Rainbird & Kienzle, 1990). Additional research is needed to determine if these data can be applied to all odor, explosive and human detection dogs and to determine if other types of working dogs (tracking, search and rescue etc.) have similar energy requirements. PMID:25755919

  6. Spatial Adaptive Wavelet Thresholding for Image Denoising

    Microsoft Academic Search

    S. Grace Chang; Martin Vetterli

    1997-01-01

    Wavelet thresholding with uniform threshold has shownsome success in denoising. For images, we propose that thiscan be improved by adjusting thresholds spatially, based onthe rationale that detailed regions such as edges and texturestolerate some noise but not blurring, whereas smoothregions tolerate blurring but not noise. The proposed algorithmis based on multiscale edge detection and imagesegmentation and then thresholding the coefficients

  7. The perils of thresholding

    NASA Astrophysics Data System (ADS)

    Font-Clos, Francesc; Pruessner, Gunnar; Moloney, Nicholas R.; Deluca, Anna

    2015-04-01

    The thresholding of time series of activity or intensity is frequently used to define and differentiate events. This is either implicit, for example due to resolution limits, or explicit, in order to filter certain small scale physics from the supposed true asymptotic events. Thresholding the birth–death process, however, introduces a scaling region into the event size distribution, which is characterized by an exponent that is unrelated to the actual asymptote and is rather an artefact of thresholding. As a result, numerical fits of simulation data produce a range of exponents, with the true asymptote visible only in the tail of the distribution. This tail is increasingly difficult to sample as the threshold is increased. In the present case, the exponents and the spurious nature of the scaling region can be determined analytically, thus demonstrating the way in which thresholding conceals the true asymptote. The analysis also suggests a procedure for detecting the influence of the threshold by means of a data collapse involving the threshold-imposed scale.

  8. Resonance {eta} Prime -meson photoproduction on protons at photon energies from the reaction threshold to 3700 MeV

    SciTech Connect

    Tryasuchev, V. A., E-mail: tva@tpu.ru [National Research Tomsk Polytechnical University (Russian Federation)

    2013-06-15

    The parameters of six resonances of the isobar model for {eta} Prime -meson photoproduction were fitted to experimental differential cross sections for the reaction {gamma}{pi} {yields} {eta} Prime p that weremeasured by the CLAS-2009 and CBELSA/TAPS Collaborations (Mainz, Germany). It was shown that, in the photon energy region from the reaction threshold to 3700MeV, a good description of the experimental cross sections was attained by taking into account the contributions of high-angular-momenta heavy resonances alone.

  9. Essays on price dynamics, discovery, and dynamic threshold effects among energy spot markets in North America

    NASA Astrophysics Data System (ADS)

    Park, Haesun

    2005-12-01

    Given the role electricity and natural gas sectors play in the North American economy, an understanding of how markets for these commodities interact is important. This dissertation independently characterizes the price dynamics of major electricity and natural gas spot markets in North America by combining directed acyclic graphs with time series analyses. Furthermore, the dissertation explores a generalization of price difference bands associated with the law of one price. Interdependencies among 11 major electricity spot markets are examined in Chapter II using a vector autoregression model. Results suggest that the relationships between the markets vary by time. Western markets are separated from the eastern markets and the Electricity Reliability Council of Texas. At longer time horizons these separations disappear. Palo Verde is the important spot market in the west for price discovery. Southwest Power Pool is the dominant market in Eastern Interconnected System for price discovery. Interdependencies among eight major natural gas spot markets are investigated using a vector error correction model and the Greedy Equivalence Search Algorithm in Chapter III. Findings suggest that the eight price series are tied together through six long-run cointegration relationships, supporting the argument that the natural gas market has developed into a single integrated market in North America since deregulation. Results indicate that price discovery tends to occur in the excess consuming regions and move to the excess producing regions. Across North America, the U.S. Midwest region, represented by the Chicago spot market, is the most important for price discovery. The Ellisburg-Leidy Hub in Pennsylvania and Malin Hub in Oregon are important for eastern and western markets. In Chapter IV, a threshold vector error correction model is applied to the natural gas markets to examine nonlinearities in adjustments to the law of one price. Results show that there are nonlinear adjustments to the law of one price in seven pair-wise markets. Four alternative cases for the law of one price are presented as a theoretical background. A methodology is developed for finding a threshold cointegration model that accounts for seasonality in the threshold levels. Results indicate that dynamic threshold effects vary depending on geographical location and whether the markets are excess producing or excess consuming markets.

  10. A lucky drift model, including a soft threshold energy, for the relation between gate and substrate currents in MOSFETs

    NASA Astrophysics Data System (ADS)

    Tanaka, Sumio

    1989-11-01

    Substrate and gate currents in MOSFETs are formulated by interpreting the lucky drift model with a soft threshold energy from the distribution function point of view. A modified Keldysh formula is introduced to the ionization relaxation time. Unknown parameters in the formulation are determined by fitting the calculation to the measured relations between gate and substrate currents in MOSFETs. Impact ionization coefficient reported by Lee et al. [16], is also subsidiarily used for determining the parameters. The model can eliminate the nonphysical fitting parameter on the Schottky barrier lowering effect, which was necessary in past models. Fitting parameters concerning the ionization relaxation time, thus obtained, are compared with various theoretical calculations. It is recognized that the relation between gate and substrate currents in MOSFETs reflects the energy dependent ionization rate which originates from electron-electron interaction in the complicated energy band structure of silicon.

  11. Lowered threshold energy for femtosecond laser induced optical breakdown in a water based eye model by aberration correction with adaptive optics

    PubMed Central

    Hansen, Anja; Géneaux, Romain; Günther, Axel; Krüger, Alexander; Ripken, Tammo

    2013-01-01

    In femtosecond laser ophthalmic surgery tissue dissection is achieved by photodisruption based on laser induced optical breakdown. In order to minimize collateral damage to the eye laser surgery systems should be optimized towards the lowest possible energy threshold for photodisruption. However, optical aberrations of the eye and the laser system distort the irradiance distribution from an ideal profile which causes a rise in breakdown threshold energy even if great care is taken to minimize the aberrations of the system during design and alignment. In this study we used a water chamber with an achromatic focusing lens and a scattering sample as eye model and determined breakdown threshold in single pulse plasma transmission loss measurements. Due to aberrations, the precise lower limit for breakdown threshold irradiance in water is still unknown. Here we show that the threshold energy can be substantially reduced when using adaptive optics to improve the irradiance distribution by spatial beam shaping. We found that for initial aberrations with a root-mean-square wave front error of only one third of the wavelength the threshold energy can still be reduced by a factor of three if the aberrations are corrected to the diffraction limit by adaptive optics. The transmitted pulse energy is reduced by 17% at twice the threshold. Furthermore, the gas bubble motions after breakdown for pulse trains at 5 kilohertz repetition rate show a more transverse direction in the corrected case compared to the more spherical distribution without correction. Our results demonstrate how both applied and transmitted pulse energy could be reduced during ophthalmic surgery when correcting for aberrations. As a consequence, the risk of retinal damage by transmitted energy and the extent of collateral damage to the focal volume could be minimized accordingly when using adaptive optics in fs-laser surgery. PMID:23761849

  12. Luteinizing Hormone Pulsatility Is Disrupted at a Threshold of Energy Availability in Regularly Menstruating Women

    Microsoft Academic Search

    ANNE B. LOUCKS; JEAN R. THUMA

    2010-01-01

    To investigate the dependence of LH pulsatility on energy availability (dietary energy intake minus exercise energy ex- penditure), we measured LH pulsatility after manipulating the energy availability of 29 regularly menstruating, habitu- ally sedentary, young women of normal body composition for 5 d in the early follicular phase. Subjects expended 15 kcal\\/kg of lean body mass (LBM) per day in

  13. The photoproduction of ?-mesons off protons by using a beam of linearly polarized photons at threshold energies

    NASA Astrophysics Data System (ADS)

    Salamanca Bernal, Julian Andres

    Observables from vector meson photoproduction by linearly-polarized photons can be expressed in term of bilinear combinations of helicity amplitudes parameterized by the Spin Density Matrix Elements (SDMEs). These SDMEs give straightforward relations for understanding the nature of the parity exchange at threshold energies, as well as for extracting signatures of the Okubo-Zweig-Iizuka violation. Measurement of SDMEs for g? p ??p in the photon energy range of 1.7 to 1.9 GeV (momentum transfer squared t range of -1.2 to -0.25 GeV2) and 1.9 to 2.1 GeV (t range of -1.4 to -0.25 GeV 2) from the g8b experimental data collected in the summer of 2005 in the Hall B of Jefferson Lab are reported herein.

  14. Collision-induced desorption of ammonia chemisorbed on Pt{111}: From direct measurement of the threshold energy to determination of the surface-adsorbate bond strength

    NASA Astrophysics Data System (ADS)

    Szulczewski, Gregory; Levis, Robert J.

    1995-12-01

    We report the desorption of a chemisorbed polyatomic adsorbate from a transition metal surface by a beam of neutral, energetic Ar atoms. From direct measurement of the threshold energy for collision-induced desorption we calculate the surface-adsorbate bond energy. The absolute cross sections for NH3 desorption at one-quarter of a monolayer coverage were measured for Ar beam energies up to ˜3 eV at incident angles of 0°, 30°, 45°, and 60°. For the NH3/Pt{111} adsorbate-surface system, the threshold desorption energy is found to be 1.95±0.17 eV. Using a classical energy transfer mechanism this threshold energy corresponds to a bond energy of 1.1±0.1 eV using an effective mass of 1 Pt atom. The threshold desorption energy scales with the total energy of the noble gas atoms for each angle of incidence. This result is consistent with a strong lateral corrugation in the NH3/Pt{111} potential energy surface and a similar ejection mechanism at each angle.

  15. Threshold of detection of Cryptosporidium oocysts in human stool specimens: evidence for low sensitivity of current diagnostic methods.

    PubMed Central

    Weber, R; Bryan, R T; Bishop, H S; Wahlquist, S P; Sullivan, J J; Juranek, D D

    1991-01-01

    To determine the minimum number of Cryptosporidium oocysts that can be detected in stool specimens by diagnostic procedures, stool samples seeded with known numbers of Cryptosporidium parvum oocysts were processed by the modified Formalin-ethyl acetate (FEA) stool concentration method. FEA concentrates were subsequently examined by both the modified cold Kinyoun acid-fast (AF) staining and fluorescein-tagged monoclonal antibody (immunofluorescence [IF]) techniques. Oocysts were more easily detected in watery diarrheal stool specimens than they were in formed stool specimens. For watery stool specimens, a 100% detection rate was accomplished at a concentration of 10,000 oocysts per g of stool by both the AF staining and IF techniques. In formed stool specimens, 100% of specimens seeded with 50,000 oocysts per gram of stool were detected by the IF technique, whereas 500,000 oocysts per g of stool were needed for a 100% detection rate by AF staining. Counting of all oocysts on IF slides indicated a mean oocyst loss ranging from 51.2 to 99.6%, depending on the stool consistency as determined by the FEA concentration procedure. Our findings suggest that the most commonly used coprodiagnostic techniques may fail to detect cryptosporidiosis in many immunocompromised and immunocompetent individuals. PMID:1715881

  16. The Nature of Psychological Thresholds

    ERIC Educational Resources Information Center

    Rouder, Jeffrey N.; Morey, Richard D.

    2009-01-01

    Following G. T. Fechner (1966), thresholds have been conceptualized as the amount of intensity needed to transition between mental states, such as between a states of unconsciousness and consciousness. With the advent of the theory of signal detection, however, discrete-state theory and the corresponding notion of threshold have been discounted.…

  17. Test-retest reliability of a new device for assessing ankle joint threshold to detect passive movement in healthy adults.

    PubMed

    Sun, Wei; Song, Qipeng; Yu, Bing; Zhang, Cui; Mao, Dewei

    2015-08-01

    This study aimed to evaluate the test-retest reliability of a new device for assessing ankle joint kinesthesia. This device could measure the passive motion threshold of four ankle joint movements, namely plantarflexion, dorsiflexion, inversion and eversion. A total of 21 healthy adults, including 13 males and 8 females, participated in the study. Each participant completed two sessions on two separate days with 1-week interval. The sessions were administered by the same experimenter in the same laboratory. At least 12 trials (three successful trials in each of the four directions) were performed in each session. The mean values in each direction were calculated and analysed. The ICC values of test-retest reliability ranged from 0.737 (dorsiflexion) to 0.935 (eversion), whereas the SEM values ranged from 0.21° (plantarflexion) to 0.52° (inversion). The Bland-Altman plots showed that the reliability of plantarflexion-dorsiflexion was better than that of inversion-eversion. The results evaluated the reliability of the new device as fair to excellent. The new device for assessing kinesthesia could be used to examine the ankle joint kinesthesia. PMID:25712530

  18. Zero Kinetic Energy Photofragment Spectroscopy: The Threshold Dissociation of NO2 J. A. Mueller, S. A. Rogers, and Paul L. Houston*

    E-print Network

    Houston, Paul L.

    Zero Kinetic Energy Photofragment Spectroscopy: The Threshold Dissociation of NO2 J. A. Mueller, S been developed and applied to the photodissociation of NO2. Photofragments with zero recoil kinetic. Called zero kinetic energy (ZKE) photofragment spectroscopy, the technique is most useful

  19. Doppler tuning vuv spectroscopy of D{sup -} over an extended photon-energy range around the n=2 threshold

    SciTech Connect

    Balling, P.; Raarup, M. K.; Elstroem, U. V.; Martinussen, R.; Petrunin, V. V.; Andersen, T. [Department of Physics and Astronomy, University of Aarhus, DK-8000 Aarhus C (Denmark)

    2007-10-15

    The giant (or shape) resonance in the photodetachment cross section of D{sup -} above the n=2 threshold has been subjected to high-resolution vacuum ultraviolet spectroscopy performed by Doppler tuning of ions stored in the ASTRID storage ring. In order to prevent changes in the overlap between laser and ion beams over the large kinetic-energy range employed in the experiment, a new ion-beam-positioning method based on a quadrupole-shunt technique was applied. The study presents an accurate measurement of parameters for the resonance, which is also denoted {sub 2}(0){sub 2}{sup +} {sup 1}P{sup o}. The resonance has a width of 26(2) meV while the asymmetry parameter q of the Fano profile is 3.2(0.4), which is at variance with the most recent theoretical calculations.

  20. Doppler tuning vuv spectroscopy of D- over an extended photon-energy range around the n=2 threshold

    NASA Astrophysics Data System (ADS)

    Balling, P.; Raarup, M. K.; Elstrøm, U. V.; Martinussen, R.; Petrunin, V. V.; Andersen, T.

    2007-10-01

    The giant (or shape) resonance in the photodetachment cross section of D- above the n=2 threshold has been subjected to high-resolution vacuum ultraviolet spectroscopy performed by Doppler tuning of ions stored in the ASTRID storage ring. In order to prevent changes in the overlap between laser and ion beams over the large kinetic-energy range employed in the experiment, a new ion-beam-positioning method based on a quadrupole-shunt technique was applied. The study presents an accurate measurement of parameters for the resonance, which is also denoted {0}22+P1o . The resonance has a width of 26(2) meV while the asymmetry parameter q of the Fano profile is 3.2(0.4), which is at variance with the most recent theoretical calculations.

  1. s-wave threshold in electron attachment - Observations and cross sections in CCl4 and SF6 at ultralow electron energies

    NASA Technical Reports Server (NTRS)

    Chutjian, A.; Alajajian, S. H.

    1985-01-01

    The threshold photoionization method was used to study low-energy electron attachment phenomena in and cross sections of CCl4 and SF6 compounds, which have applications in the design of gaseous dielectrics and diffuse discharge opening switches. Measurements were made at electron energies from below threshold to 140 meV at resolutions of 6 and 8 meV. A narrow resolution-limited structure was observed in electron attachment to CCl4 and SF6 at electron energies below 10 meV, which is attributed to the divergence of the attachment cross section in the limit epsilon, l approaches zero. The results are compared with experimental collisional-ionization results, electron-swarm unfolded cross sections, and earlier threshold photoionization data.

  2. The 8Li(p,?)5He reaction at low energies, and 9Be spectroscopy around the proton threshold

    NASA Astrophysics Data System (ADS)

    Mendes, D. R., Jr.; Lépine-Szily, A.; Descouvemont, P.; Lichtenthäler, R.; Guimarães, V.; de Faria, P. N.; Barioni, A.; Pires, K. C. C.; Morcelle, V.; Pampa Condori, R.; Morais, M. C.; Leistenschneider, E.; Lima, C. E. F.; Zamora, J. C.; Alcantara, J. A.; Zagatto, V.; Assunção, M.; Shorto, J. M. B.

    2012-12-01

    We present a direct measurement of the low-energy 8Li(p,?)5He cross section, using a radioactive 8Li beam impinging on a thick target. With four beam energies, we cover the energy range between Ec.m.=0.2 and 2.1 MeV. An R-matrix analysis of the data is performed and suggests the existence of two broad overlapping resonances (5/2+ at Ec.m.=1.69 MeV and 7/2+ at Ec.m.=1.76 MeV). At low energies our data are sensitive to the properties of a subthreshold state (Ex=16.67 MeV) and of two resonances above threshold. These resonances were observed in previous experiments. The R-matrix fit confirms spin assignments, and provides partial widths. We propose a new 8Li(p,?)5He reaction rate and briefly discuss its influence in nuclear astrophysics.

  3. Cognitive load and detection thresholds in car following situations: safety implications for using mobile (cellular) telephones while driving

    Microsoft Academic Search

    Dave Lamble; Tatu Kauranen; Matti Laakso; Heikki Summala

    1999-01-01

    This study was aimed at investigating drivers’ ability to detect a car ahead decelerating, while doing mobile phone related tasks. Nineteen participants aged between 20 and 29 years, (2000–125?000 km driving experience) drove at 80 km\\/h, 50 m behind a lead car, on a 30 km section of motorway in normal traffic. During each trial the lead car started to

  4. Near threshold dynamics and dissociation energy of the reaction H 2CO ? HCO + H

    NASA Astrophysics Data System (ADS)

    Terentis, Andrew C.; Kable, Scott H.

    1996-08-01

    The state-to-state dynamics of the gas phase reaction H 2CO ( v, J, Ka, Kc) + hv ? H + HCO( v, N, S, Ka, Kc) have been explored in a supersonic free jet. Seven rotational states within the 2 14 3 vibrational level of H 2CO were excited and the population distribution of the HCO ( v = 0, N, S, Ka, Kc) product states measured. The distributions are constrained severely by the available energy in the reaction with the lowest H 2CO state producing HCO in only three rotational states. Careful matching of the H 2CO and HCO energy levels leads to an estimate of the dissociation energy of the above reaction of 30328.5 ± 0.5 cm -, which lead us to an estimate of the standard heat of formation of the formyl radical of ?Hf0 = 42.5 ± 0.5 kJ mol -1.

  5. Comment on 'Rate coefficients for photoinitiated NO 2 unimolecular decomposition: energy dependence in the threshold regime' [Chem. Phys. Lett. 358 (2002) 71

    NASA Astrophysics Data System (ADS)

    Abel, B.; Grebenshchikov, S. Y.; Schinke, R.; Schwarzer, D.

    2003-01-01

    Recently, Wittig and co-workers have published rate coefficients k( E) for the unimolecular decomposition of photoinitiated NO 2 close to the dissociation threshold [Chem. Phys. Lett. 358 (2002) 71]. They found out that k( E) for low angular momentum J exhibits a strong increase within 25 cm -1 of the reaction threshold. The authors emphasize that their experimental results are surprising and cannot be understood quantitatively on the basis of current theory on NO 2. In this Comment we demonstrate that recent quantum mechanical calculations of NO 2 resonances on a global 3D-potential energy surface can indeed explain their data close to the dissociation threshold as well as for larger excess energies.

  6. Universal Angular Probability Distribution of Three Particles near Zero Energy Threshold

    E-print Network

    Dmitry K. Gridnev

    2013-03-12

    We study bound states of a 3--particle system in $\\mathbb{R}^3$ described by the Hamiltonian $H(\\lambda_n) = H_0 + v_{12} + \\lambda_n (v_{13} + v_{23})$, where the particle pair $\\{1,2\\}$ has a zero energy resonance and no bound states, while other particle pairs have neither bound states nor zero energy resonances. It is assumed that for a converging sequence of coupling constants $\\lambda_n \\to \\lambda_{cr}$ the Hamiltonian $H(\\lambda_n)$ has a sequence of levels with negative energies $E_n$ and wave functions $\\psi_n$, where the sequence $\\psi_n$ totally spreads in the sense that $\\lim_{n \\to \\infty}\\int_{|\\zeta| \\leq R} |\\psi_n (\\zeta)|^2 d\\zeta = 0$ for all $R>0$. We prove that for large $n$ the angular probability distribution of three particles determined by $\\psi_n$ approaches the universal analytical expression, which does not depend on pair--interactions. The result has applications in Efimov physics and in the physics of halo nuclei.

  7. Low energy threshold analysis of the phase I and phase II data sets of the Sudbury neutrino observatory

    SciTech Connect

    Seibert, S R [Los Alamos National Laboratory; Hime, A [Los Alamos National Laboratory; Elliott, S R [Los Alamos National Laboratory; Rielage, K [Los Alamos National Laboratory

    2009-01-01

    Results are reported from a joint analysis of Phase I and Phase II data from the Sudbury Neutrino Observatory. The effective electron kinetic energy threshold used is T{sub eff} = 3.5 MeV, the lowest analysis threshold yet achieved with water Cherenkov detector data. In units of 10{sup 6} cm{sup -2} s{sup =1}, the total flux of active-flavor neutrinos from {sup 8}B decay in the Sun measured using the neutral current (NC) reaction of neutrinos on deuterons, with no constraint on the {sup 8}B neutrino energy spectrum, is found to be {Phi}{sub NC} = 5.140{sub -0.158}{sup +0.160}(stat){sub -0.117}{sup +0.132}(syst). These uncertainties are more than a factor of two smaller than previously published results. Also presented are the spectra of recoil electrons from the charged current reaction of neutrinos on deuterons and the elastic scattering of electrons. A fit to the SNO data in which the free parameters directly describe the total {sup 8}B neutrino flux and the energy-dependent Ve survival probability provides a measure of the total {sup 8}B neutrino flux {Phi}{sub 8{sub B}} = 5.046{sub -0.152}{sup +0.159}(stat){sub -0.123}{sup +0.107}(syst). Combining these new results with results of all other solar experiments and the KamLAND reactor experiment yields best-fit values of the mixing parameters of {theta}{sub 12} = 34.06{sub -0.84}{sup +1.16} degrees and {Delta}m{sub 21}{sup 2} = 7.59{sub -0.21}{sup +0.20} x 10{sup -5} eV{sup 2}. The global value of {Phi}{sub 8{sub B}} is extracted to a precision of {sub -2.95}{sup +2.38}%. In a three-flavor analysis the best fit value of sin{sup 2} {theta}{sub 13} is 2.00{sub -1.63}{sup +2.09} x 10{sup -2}. Interpreting this as a limit implies an upper bound of sin{sup 2} {theta}{sub 13} < 0.057 (95% C. L.).

  8. Low Energy Threshold Analysis of the Phase I and Phase II Data Sets of the Sudbury Neutrino Observatory

    E-print Network

    The SNO Collaboration

    2010-06-09

    Results are reported from a joint analysis of Phase I and Phase II data from the Sudbury Neutrino Observatory. The effective electron kinetic energy threshold used is T_eff=3.5 MeV, the lowest analysis threshold yet achieved with water Cherenkov detector data. In units of 10^6 cm^{-2} s^{-1}, the total flux of active-flavor neutrinos from 8B decay in the Sun measured using the neutral current (NC) reaction of neutrinos on deuterons, with no constraint on the 8B neutrino energy spectrum, is found to be Phi_NC = 5.140 ^{+0.160}_{-0.158} (stat) ^{+0.132}_{-0.117} (syst). These uncertainties are more than a factor of two smaller than previously published results. Also presented are the spectra of recoil electrons from the charged current reaction of neutrinos on deuterons and the elastic scattering of electrons. A fit to the SNO data in which the free parameters directly describe the total 8B neutrino flux and the energy-dependent nu_e survival probability provides a measure of the total 8B neutrino flux Phi_8B = 5.046 ^{+0.159}_{-0.152} (stat) ^{+0.107}_{-0.123} (syst). Combining these new results with results of all other solar experiments and the KamLAND reactor experiment yields best-fit values of the mixing parameters of theta_{12}=34.06 ^{+1.16}_{-0.84} degrees and Delta m^2_{21}=7.59 ^{+0.20}_{-0.21} x 10^{-5} eV^2. The global value of Phi_8B is extracted to a precision of ^{+2.38}_{-2.95} %. In a three-flavor analysis the best fit value of sin^2\\theta_{13} is 2.00 ^{+2.09}_{-1.63} x 10^{-2}. Interpreting this as a limit implies an upper bound of sin^2\\theta_{13} < 0.057 (95% C. L.).

  9. On the Energy Detection of Unknown Signals Over Fading Channels

    Microsoft Academic Search

    Fadel F. Digham; Mohamed-slim Alouini; Marvin K. Simon

    2007-01-01

    This letter addresses the problem of energy detection of an unknown signal over a multipath channel. It starts with the no-diversity case, and presents some alternative closed-form expressions for the probability of detection to those recently reported in the literature. Detection capability is boosted by implementing both square-law combining and square-law selection diversity schemes

  10. Direct measurement of the energy thresholds to conformational isomerization. II. 3-indole-propionic acid and its water-containing complex

    E-print Network

    Zwier, Timothy S.

    extend these measurements to three-indole-propionic acid IPA . IPA and TRA differ from tryptophanDirect measurement of the energy thresholds to conformational isomerization. II. 3-indole-propionic direct experimental bounds on the energetic barriers to conformational isomerization in 3-indole-propionic

  11. Reexamination of high-energy above-threshold ionization (ATI): An alternative strong-field ATI model

    SciTech Connect

    Usachenko, V.I.; Pazdzersky, V.A.; McIver, J.K. [Institute of Applied Laser Physics of Uzbekistan Academy of Sciences, Nakashlyk Street 1, Tashkent 700185 (Uzbekistan); Physics Department of National University of Uzbekistan, Vuzgorodok, Tashkent 700174 (Uzbekistan); Center for Advanced Studies and Department of Physics and Astronomy, University of New Mexico, Albuquerque, New Mexico 87131 (United States)

    2004-01-01

    The multiphoton strong-field phenomenon of high-energy above-threshold ionization (or high-order ATI) of an isolated atomic system exposed to an intense monochromatic linearly polarized laser field is considered analytically and studied numerically within the framework of an alternative nonrelativistic strong-field approach developed earlier for theoretical treatment of high-order harmonic generation process. The related proposed alternative strong-field ATI model is fully quantum mechanical and mainly based on the Keldysh approximation combined with making use of the essential states method (along with the pole approximation). Applying together these two methods allows for representation of the total ATI amplitude in a closed and compact analytical (the so-called factorized) form quite transparent for interpretation and available for direct numerical calculations. To demonstrate the model applicability, a number of certain photoelectron spectra produced by various atomic species (mostly noble gas atoms and negative ions) have been calculated numerically and shown to reproduce the well-known conventional semiclassical rule for the extent of high-energy plateau and position of its cutoff energy. All the calculated photoelectron spectra as well as the specific details of respective angular distributions (viz., their sidelobes or so-called rings) corresponding to a certain photoelectron peak within a high-energy plateau region (formed primarily by rescattered photoelectrons) demonstrate a very credible behavior within a broad and most interesting region of the problem parameters. Moreover, they all are also in an excellent or fairly good accordance with typical ones measured in standard ATI experiments or calculated by other authors within different (analytically more sophisticated or computationally very demanding) approaches and methods developed earlier.

  12. Research on a novel synchronization and detection scheme used in energy detection UWB receiver

    Microsoft Academic Search

    Ying Tang; Yue Ruan

    2011-01-01

    Ultra-wideband (UWB) is a modern radio technology that works at extremely low energy levels. It is popularly used in short-range, low power and low cost communications such as RFIDs. This paper presents a UWB receiver using energy detection scheme with on-off keying (OOK) modulation. A novel synchronization and detection algorithm called energy offset based scheme is investigated and used in

  13. One-photon mass-analyzed threshold ionization (MATI) spectroscopy of pyridine: determination of accurate ionization energy and cationic structure.

    PubMed

    Lee, Yu Ran; Kang, Do Won; Kim, Hong Lae; Kwon, Chan Ho

    2014-11-01

    Ionization energies and cationic structures of pyridine were intensively investigated utilizing one-photon mass-analyzed threshold ionization (MATI) spectroscopy with vacuum ultraviolet radiation generated by four-wave difference frequency mixing in Kr. The present one-photon high-resolution MATI spectrum of pyridine demonstrated a much finer and richer vibrational structure than that of the previously reported two-photon MATI spectrum. From the MATI spectrum and photoionization efficiency curve, the accurate ionization energy of the ionic ground state of pyridine was confidently determined to be 73,570 ± 6 cm(-1) (9.1215 ± 0.0007 eV). The observed spectrum was almost completely assigned by utilizing Franck-Condon factors and vibrational frequencies calculated through adjustments of the geometrical parameters of cationic pyridine at the B3LYP/cc-pVTZ level. A unique feature unveiled through rigorous analysis was the prominent progression of the 10 vibrational mode, which corresponds to in-plane ring bending, and the combination of other totally symmetric fundamentals with the ring bending overtones, which contribute to the geometrical change upon ionization. Notably, the remaining peaks originate from the upper electronic state ((2)A2), as predicted by high-resolution photoelectron spectroscopy studies and symmetry-adapted cluster configuration interaction calculations. Based on the quantitatively good agreement between the experimental and calculated results, it was concluded that upon ionization the pyridine cation in the ground electronic state should have a planar structure of C(2v) symmetry through the C-N axis. PMID:25381510

  14. One-photon mass-analyzed threshold ionization (MATI) spectroscopy of pyridine: Determination of accurate ionization energy and cationic structure

    SciTech Connect

    Lee, Yu Ran; Kang, Do Won; Kim, Hong Lae, E-mail: chkwon@kangwon.ac.kr, E-mail: hlkim@kangwon.ac.kr; Kwon, Chan Ho, E-mail: chkwon@kangwon.ac.kr, E-mail: hlkim@kangwon.ac.kr [Department of Chemistry and Institute for Molecular Science and Fusion Technology, College of Natural Sciences, Kangwon National University, Chuncheon 200-701 (Korea, Republic of)

    2014-11-07

    Ionization energies and cationic structures of pyridine were intensively investigated utilizing one-photon mass-analyzed threshold ionization (MATI) spectroscopy with vacuum ultraviolet radiation generated by four-wave difference frequency mixing in Kr. The present one-photon high-resolution MATI spectrum of pyridine demonstrated a much finer and richer vibrational structure than that of the previously reported two-photon MATI spectrum. From the MATI spectrum and photoionization efficiency curve, the accurate ionization energy of the ionic ground state of pyridine was confidently determined to be 73?570 ± 6 cm{sup ?1} (9.1215 ± 0.0007 eV). The observed spectrum was almost completely assigned by utilizing Franck-Condon factors and vibrational frequencies calculated through adjustments of the geometrical parameters of cationic pyridine at the B3LYP/cc-pVTZ level. A unique feature unveiled through rigorous analysis was the prominent progression of the 10 vibrational mode, which corresponds to in-plane ring bending, and the combination of other totally symmetric fundamentals with the ring bending overtones, which contribute to the geometrical change upon ionization. Notably, the remaining peaks originate from the upper electronic state ({sup 2}A{sub 2}), as predicted by high-resolution photoelectron spectroscopy studies and symmetry-adapted cluster configuration interaction calculations. Based on the quantitatively good agreement between the experimental and calculated results, it was concluded that upon ionization the pyridine cation in the ground electronic state should have a planar structure of C{sub 2v} symmetry through the C-N axis.

  15. Randomness fault detection system

    NASA Technical Reports Server (NTRS)

    Russell, B. Don (Inventor); Aucoin, B. Michael (Inventor); Benner, Carl L. (Inventor)

    1996-01-01

    A method and apparatus are provided for detecting a fault on a power line carrying a line parameter such as a load current. The apparatus monitors and analyzes the load current to obtain an energy value. The energy value is compared to a threshold value stored in a buffer. If the energy value is greater than the threshold value a counter is incremented. If the energy value is greater than a high value threshold or less than a low value threshold then a second counter is incremented. If the difference between two subsequent energy values is greater than a constant then a third counter is incremented. A fault signal is issued if the counter is greater than a counter limit value and either the second counter is greater than a second limit value or the third counter is greater than a third limit value.

  16. Low-energy neutral-particle detection in the Mont Blanc LSD experiment

    NASA Astrophysics Data System (ADS)

    Dadykin, V. L.; Korchagin, V. B.; Korchagin, P. V.; Malgin, A. S.; Riasnyi, V. G.

    1986-04-01

    The detection of positrons (at energy threshold 7 MeV) and neutrons (at 800 keV) from the capture of low-energy stellar-collapse neutrinos in the liquid-scintillation-detector (LSD) experiment at Mont Blanc Laboratory is examined analytically, with a focus on background sources imitating the antineutrino interaction. The experimental setup and the calibration results are summarized, and the neutral-particle background in the LSD is characterized on the basis of preliminary data. It is found that fast neutrons from muon-induced nuclear showers in the rock, spontaneous fission of U-238, and the decay of isotopes produced in the rock or the apparatus by thermal neutron capture are the primary background sources.

  17. Detecting Energy Patterns in Software Development

    Microsoft Academic Search

    Ashish Gupta; Thomas Zimmermann; Christian Bird; Nachiappan Nagappan; Thirumalesh Bhat; Syed Emran

    2011-01-01

    With the advent of increased computing on mobile devices such as phones and tablets, it has become crucial to pay attention to the energy consumption of mobile applications. The software engineering field is now faced with a whole new spectrum of energy-related challenges, ranging from power budgeting to testing and debugging the energy consumption. To the best of our knowledge

  18. Decentralized Computation of Threshold Crossing Alerts

    Microsoft Academic Search

    Fetahi Wuhib; Mads Dam; Rolf Stadler; Alexander Clemm

    2005-01-01

    Threshold crossing alerts (TCAs) indicate to a management system that a management variable, associated with the state, performance or health of the network, has crossed a certain threshold. The timely detection of TCAs is essential to proactive management. This paper focuses on detecting TCAs for network-level variables, which are computed from device-level variables using aggregation functions, such as SUM, MAX,

  19. Energy profiles in detection of protein structure modifications

    Microsoft Academic Search

    Dariusz Mrozek; Bozena Malysiak; Stanislaw Kozielski

    2006-01-01

    Protein structure has a big impact on the protein's activity in the living cells. Conformational modifications as an effect of biochemical reactions or environmental influences cause changes in the conformational energy distributions. Therefore, observations of the energy characteristics allow to detect structural changes of selected proteins. Moreover, having entire sets of energy characteristics it is possible to compare given protein

  20. Dissociation of internal energy-selected methyl bromide ion revealed from threshold photoelectron-photoion coincidence velocity imaging

    SciTech Connect

    Tang, Xiaofeng [Hefei National Laboratory for Physical Sciences at the Microscale and Department of Chemical Physics, University of Science and Technology of China, Hefei 230026 (China) [Hefei National Laboratory for Physical Sciences at the Microscale and Department of Chemical Physics, University of Science and Technology of China, Hefei 230026 (China); National Synchrotron Radiation Laboratory, University of Science and Technology of China, Hefei 230029 (China); Zhou, Xiaoguo, E-mail: xzhou@ustc.edu.cn, E-mail: yanbing@jlu.edu.cn; Liu, Shilin [Hefei National Laboratory for Physical Sciences at the Microscale and Department of Chemical Physics, University of Science and Technology of China, Hefei 230026 (China) [Hefei National Laboratory for Physical Sciences at the Microscale and Department of Chemical Physics, University of Science and Technology of China, Hefei 230026 (China); Synergetic Innovation Center of Quantum Information and Quantum Physics, University of Science and Technology of China, Hefei, Anhui 230026 (China); Sun, Zhongfa [Hefei National Laboratory for Physical Sciences at the Microscale and Department of Chemical Physics, University of Science and Technology of China, Hefei 230026 (China)] [Hefei National Laboratory for Physical Sciences at the Microscale and Department of Chemical Physics, University of Science and Technology of China, Hefei 230026 (China); Liu, Fuyi; Sheng, Liusi [National Synchrotron Radiation Laboratory, University of Science and Technology of China, Hefei 230029 (China)] [National Synchrotron Radiation Laboratory, University of Science and Technology of China, Hefei 230029 (China); Yan, Bing, E-mail: xzhou@ustc.edu.cn, E-mail: yanbing@jlu.edu.cn [Institute of Atomic and Molecular Physics, Jilin University, Changchun 130012 (China)] [Institute of Atomic and Molecular Physics, Jilin University, Changchun 130012 (China)

    2014-01-28

    Dissociative photoionization of methyl bromide (CH{sub 3}Br) in an excitation energy range of 10.45–16.90 eV has been investigated by using threshold photoelectron-photoion coincidence (TPEPICO) velocity imaging. The coincident time-of-flight mass spectra indicate that the ground state X{sup 2}E of CH{sub 3}Br{sup +} is stable, and both A{sup 2}A{sub 1} and B{sup 2}E ionic excited states are fully dissociative to produce the unique fragment ion of CH{sub 3}{sup +}. From TPEPICO 3D time-sliced velocity images of CH{sub 3}{sup +} dissociated from specific state-selected CH{sub 3}Br{sup +} ion, kinetic energy release distribution (KERD) and angular distribution of CH{sub 3}{sup +} fragment ion are directly obtained. Both spin-orbit states of Br({sup 2}P) atom can be clearly observed in fast dissociation of CH{sub 3}Br{sup +}(A{sup 2}A{sub 1}) ion along C–Br rupture, while a KERD of Maxwell-Boltzmann profile is obtained in dissociation of CH{sub 3}Br{sup +}(B{sup 2}E) ion. With the aid of the re-calculated potential energy curves of CH{sub 3}Br{sup +} including spin-orbit coupling, dissociation mechanisms of CH{sub 3}Br{sup +} ion in A{sup 2}A{sub 1} and B{sup 2}E states along C–Br rupture are revealed. For CH{sub 3}Br{sup +}(A{sup 2}A{sub 1}) ion, the CH{sub 3}{sup +} + Br({sup 2}P{sub 1/2}) channel is occurred via an adiabatic dissociation by vibration, while the Br({sup 2}P{sub 3/2}) formation is through vibronic coupling to the high vibrational level of X{sup 2}E state followed by rapid dissociation. C–Br bond breaking of CH{sub 3}Br{sup +}(B{sup 2}E) ion can occur via slow internal conversion to the excited vibrational level of the lower electronic states and then dissociation.

  1. CERES Detects Earth's Heat and Energy

    NASA Technical Reports Server (NTRS)

    2002-01-01

    Clouds and the Earth's Radiant Energy System, CERES, monitors solar energy reflected from the Earth and heat energy emitted from the Earth. In this image, heat energy radiated from the earth is shown in varying shades of yellow, red, blue and white. The brightest yellow areas, such as the Sahara Desert and Arabian Peninsula, are emitting the most energy out to space, while the dark blue polar regions and bright white clouds are the coldest areas on Earth, and are emitting the least energy. The animation (1.5MB) (high-res (4MB)) shows roughly a week of CERES data. For more information: CERES images through Visible Earth. CERES web site Image courtesy of the CERES instrument team

  2. Near Threshold eta Meson Production in dp Collisions

    Microsoft Academic Search

    C. Piskor-Ignatowicz; J. Smyrski; P. Moskal; H.-H. Adam; A. Budzanowski; E. Czerwinski; R. Czyzykiewicz; D. Grzonka; M. Janusz; L. Jarczyk; B. Kamys; A. Khoukaz; P. Klaja; J. Majewski; W. Oelert; J. Przerwa; J. Ritman; T. Rozek; T. Sefzick; M. Siemaszko; A. Täschner; P. Winter; M. Wolke; P. Wüstner; W. Zipper

    2007-01-01

    Preliminary results of recent measurements of the near threshold eta meson production in the dp --> dpeta reaction are presented. The experiment was performed at the COSY-Juelich accelerator with the use of the COSY-11 detection system. Data were taken for three values of deuteron beam momenta corresponding to excess energies of 3.2, 6.1 and 9.2 MeV. The energy dependence of

  3. Can the Existence of Dark Energy Be Directly Detected?

    E-print Network

    Martin L. Perl

    2008-10-06

    The majority of astronomers and physicists accept the reality of dark energy and also believe that it can only be studied indirectly through observation of the motions of stars and galaxies. In this paper I open the experimental question of whether it is possible to directly detect dark energy through the presence of dark energy density. Two thirds of this paper outlines the major aspects of dark energy density as now comprehended by the astronomical and physics community. The final third summarizes various proposals for direct detection of dark energy density or its possible effects. At this time I do not have a fruitful answer to the question: Can the Existence of Dark Energy Be Directly Detected?

  4. Online Fault Detection and Tolerance for Photovoltaic Energy Harvesting Systems

    E-print Network

    Pedram, Massoud

    Online Fault Detection and Tolerance for Photovoltaic Energy Harvesting Systems Xue Lin 1 , Yanzhi (PV systems) are subject to PV cell faults, which decrease the efficiency of PV systems and even shorten the PV system lifespan. Manual PV cell fault detection and elimination are expensive and nearly

  5. Magnitude of the threshold energy for hot electron damage in metal{endash}oxide{endash}semiconductor field effect transistors by hydrogen desorption

    SciTech Connect

    Hess, K.; Tuttle, B.; Register, F. [Beckmann Institute, University of Illinois, Urbana, Illinois 61801 (United States)] [Beckmann Institute, University of Illinois, Urbana, Illinois 61801 (United States); Ferry, D.K. [Center for Solid State Electronics Research and Department of Electrical Engineering, Arizona State University, Tempe, Arizona 85287-5706 (United States)] [Center for Solid State Electronics Research and Department of Electrical Engineering, Arizona State University, Tempe, Arizona 85287-5706 (United States)

    1999-11-01

    Based on the energetics for hydrogen desorption from the interface between silicon and silicon-dioxide, we argue that the hard threshold for this effect may be considerably lower than the previously assumed value ({approximately}3.6 eV). We support these findings further by recent experimental results related to the giant isotope effect in hydrogen related transistor degradation and the fact that degradation occurs also with relatively low supply voltages. We also show that the high threshold energy model is difficult to defend at these low voltages, even though electron{endash}electron interactions provide a mechanism to create hot electrons with energies of {approximately}3.6 eV. {copyright} {ital 1999 American Institute of Physics.} thinsp

  6. Use of threshold-specific energy model for the prediction of effects of smoking and radon exposure on the risk of lung cancer.

    PubMed

    Böhm, R; Sedlák, A; Bulko, M; Holý, K

    2014-07-01

    Lung cancer is the leading cause of cancer death in both men and women. Smoking causes 80-90% of cases of lung cancer. In this study, an attempt was made to assess the impact of cigarette smoking on the risk of lung cancer by the so-called threshold-specific energy model. This model allows to analyse the biological effects of radon daughter products on the lung tissue, and is based on the assumption that the biological effect (i.e. cell inactivation) will manifest itself after the threshold-specific energy z0 deposited in the sensitive volume of the cell is exceeded. Cigarette smoking causes, among others, an increase in the synthesis of the survivin protein that protects cells from apoptosis and thereby reduces their radiosensitivity. Based on these facts, an attempt was made to estimate the shape of the curves describing the increase in the oncological effect of radiation as a function of daily cigarette consumption. PMID:24711526

  7. INDRA, a 4? charged product detection array at GANIL

    Microsoft Academic Search

    J. Pouthas; B. Borderie; R. Dayras; E. Plagnol; M. F. Rivet; F. Saint-Laurent; J. C. Steckmeyer; G. Auger; C. O. Bacri; S. Barbey; A. Barbier; A. Benkirane; J. Benlliure; B. Berthier; E. Bougamont; P. Bourgault; P. Box; R. Bzyl; B. Cahan; Y. Cassagnou; D. Charlet; J. L. Charvet; A. Chbihi; T. Clerc; N. Copinet; D. Cussol; M. Engrand; J. M. Gautier; Y. Huguet; O. Jouniaux; J. L. Laville; P. Le Botlan; A. Leconte; R. Legrain; P. Lelong; M. Le Guay; L. Martina; C. Mazur; P. Mosrin; L. Olivier; J. P. Passerieux; S. Pierre; B. Piquet; E. Plaige; E. C. Pollacco; B. Raine; A. Richard; J. Ropert; C. Spitaels; L. Stab; D. Sznajderman; L. Tassan-Got; J. Tillier; M. Tripon; P. Vallerand; C. Volant; P. Volkov; J. P. Wieleczko; G. Wittwer

    1995-01-01

    INDRA, a new and innovative highly segmented detector for light charged particles and fragments is described. It covers geometrically 90% of the 4? solid angle and has very low detection thresholds. The detector, operated under vacuum, is axially symmetric and segmented in 336 independent cells allowing efficient detection of high multiplicity events. Nucleus identification down to very low energy threshold

  8. Predicting lactate threshold using ventilatory threshold.

    PubMed

    Plato, P A; McNulty, M; Crunk, S M; Tug Ergun, A

    2008-09-01

    Lactate threshold is an important reference point when setting training intensities for endurance athletes. Ventilatory threshold has been used as a noninvasive estimate of lactate threshold, but appears to underestimate training intensity for many athletes. This study evaluated whether data obtained during a noninvasive, maximal exercise test could be used to predict lactate threshold. Maximal oxygen consumption (55+/-2 ml O(2) x kg(-1) x min(-1)) and heart rate at the ventilatory threshold (V-slope method) were determined for 19 cyclists (10 men, 9 women, 35+/-2 years). Cyclists also performed a lactate threshold test, consisting of 8 min stages at power outputs below, at, and above the ventilatory threshold. Heart rate associated with the lactate threshold was determined using the Dmax method. The correlation coefficient between heart rates at the ventilatory and lactate thresholds was 0.67, indicating 45% shared variance. The best fitting model to predict heart rate at the lactate threshold included heart rate at the ventilatory threshold, gender, body weight, and an interaction between gender and body weight. Using this model, R(2) was 0.70. Thus, heart rate at the ventilatory threshold may be adjusted to more accurately predict a heart rate that corresponds to the lactate threshold for recreational cyclists. PMID:18214811

  9. Robust Fault Detection of Wind Energy Conversion Systems Based on Dynamic Neural Networks

    PubMed Central

    Talebi, Nasser; Sadrnia, Mohammad Ali; Darabi, Ahmad

    2014-01-01

    Occurrence of faults in wind energy conversion systems (WECSs) is inevitable. In order to detect the occurred faults at the appropriate time, avoid heavy economic losses, ensure safe system operation, prevent damage to adjacent relevant systems, and facilitate timely repair of failed components; a fault detection system (FDS) is required. Recurrent neural networks (RNNs) have gained a noticeable position in FDSs and they have been widely used for modeling of complex dynamical systems. One method for designing an FDS is to prepare a dynamic neural model emulating the normal system behavior. By comparing the outputs of the real system and neural model, incidence of the faults can be identified. In this paper, by utilizing a comprehensive dynamic model which contains both mechanical and electrical components of the WECS, an FDS is suggested using dynamic RNNs. The presented FDS detects faults of the generator's angular velocity sensor, pitch angle sensors, and pitch actuators. Robustness of the FDS is achieved by employing an adaptive threshold. Simulation results show that the proposed scheme is capable to detect the faults shortly and it has very low false and missed alarms rate. PMID:24744774

  10. Observation and analysis of structural changes in fused silica by continuous irradiation with femtosecond laser light having an energy density below the laser-induced damage threshold

    PubMed Central

    Kawazoe, Tadashi; Yatsui, Takashi; Naruse, Makoto; Ohtsu, Motoichi

    2014-01-01

    Summary The laser-induced damage threshold (LIDT) is widely used as an index for evaluating an optical component’s resistance to laser light. However, a degradation in the performance of an optical component is also caused by continuous irradiation with laser light having an energy density below the LIDT. Therefore, here we focused on the degradation in performance of an optical component caused by continuous irradiation with femtosecond laser light having a low energy density, i.e., laser-induced degradation. We performed an in situ observation and analysis of an increase in scattering light intensity in fused silica substrates. In experiments conducted using a pulsed laser with a wavelength of 800 nm, a pulse width of 160 fs and pulse repetition rate of 1 kHz, we found that the scattered light intensity increased starting from a specific accumulated fluence, namely, that the laser-induced degradation had a threshold. We evaluated the threshold fluence F t as 6.27 J/cm2 and 9.21 J/cm2 for the fused silica substrates with surface roughnesses of 0.20 nm and 0.13 nm in R a value, respectively, showing that the threshold decreased as the surface roughness increased. In addition, we found that the reflected light spectrum changed as degradation proceeded. We analyzed the details of the degradation by measuring instantaneous reflectance changes with a pump–probe method; we observed an increase in the generation probability of photogenerated carriers in a degraded silica substrate and a damaged silica substrate and observed a Raman signal originating from a specific molecular structure of silica. From these findings, we concluded that compositional changes in the molecular structure occurred during degradation due to femtosecond laser irradiation having an energy density below the LIDT. PMID:25247116

  11. (p, n) Threshold Measurements on Na, Al, Cu, Ga, Ge, Se, Y, and Sn

    Microsoft Academic Search

    Kotoyuki Okano; Kazuaki Nishimura

    1963-01-01

    Q-values have been measured for (p, n) reactions on Na23, Al27, Cu63, Cu65, Ga69, Ge74, Se77, Se78, Se80, Y89, Sn118, and Sn120 by detecting slow neutrons associated with the thresholds. Using the well established threshold energies of (p, n) reactions on Li7, C13, and F19 as calibration standards, the following Q-values were obtained: \\\\includegraphics{dummy.eps} These results are compared with the

  12. Energy-Based Attack Detection in Networked Control Emeka Eyisi

    E-print Network

    Koutsoukos, Xenofon D.

    .koutsoukos@vanderbilt.edu ABSTRACT The increased prevalence of attacks on Cyber-Physical Systems (CPS) as well as the safety of a system's energy. We propose a discrete-time Energy-Based Attack Detection mech- anism for networked cyber and protection (e.g., firewalls); H.1.1 [Models and Princi- ples]: Systems and Information Theory

  13. Signal detection without finite-energy limits to quantum resolution

    E-print Network

    Alfredo Luis

    2013-01-16

    We show that there are extremely simple signal detection schemes where the finiteness of energy resources places no limit to the resolution. On the contrary, larger resolution can be obtained with lower energy. To this end the generator of the signal-dependent transformation encoding the signal information on the probe state must be different from the energy. We show that the larger the deviation of the probe state from being minimum-uncertainty state, the better the resolution.

  14. Resonant Raman scattering contribution to attenuation of x rays at energies in lower vicinity of the K-shell ionization threshold of some elements

    SciTech Connect

    Kumar, Sanjeev; Sharma, Veena; Kumar, Sunil; Alrakabi, Muhanad; Mehta, D.; Singh, Nirmal [Department of Physics, Panjab University, Chandigarh-160 014 (India)

    2009-05-15

    Attenuation of the x rays and gamma rays in the {sub 22}Ti, {sub 41}Nb, {sub 69}Tm, {sub 70}Yb, and {sub 71}Lu elements have been measured with special emphasis for the x ray energies (E{sub in}) in lower vicinity of the K shell ionization threshold (B{sub K}) of the element. The incident photon beam is obtained from decay of the {sup 55}Fe, {sup 241}Am, and {sup 57}Co radioisotopes, and fluorescence of the {sub 23}V, {sub 70}Yb, {sub 71}Lu, {sub 74}W, {sub 76}Os, and {sub 90}Th targets excited by the x rays and gamma rays from the radioisotopes. The measurements were performed using energy dispersive setups involving Ge detectors. The measured attenuation coefficients agree with the available theoretical values except at the photon energies with (B{sub K}-E{sub in}) less than or nearly equal to the K-shell width (GAMMA{sub K}), where significant positive deviations as large as factor of 2 have been observed. In view of reliability of the available theoretical cross sections for the photoionization and the photon scattering processes, the magnitude of positive alteration at the photon energy in lower vicinity of the ionization threshold is attributed to the K shell resonant Raman scattering (RRS) process and the corresponding cross sections have been deduced. Possible matrix effects in the energy dispersive x ray spectrometry due to RRS are also discussed.

  15. Automatic anomaly detection in high energy collider data

    E-print Network

    Simon de Visscher; Michel Herquet

    2011-04-13

    We address the problem of automatic anomaly detection in high energy collider data. Our approach is based on the random generation of analytic expressions for kinematical variables, which can then be evolved following a genetic programming procedure to enhance their discriminating power. We apply this approach to three concrete scenarios to demonstrate its possible usefulness, both as a detailed check of reference Monte-Carlo simulations and as a model independent tool for the detection of New Physics signatures.

  16. Near-threshold Photoproduction of Phi Mesons from Deuterium

    SciTech Connect

    Qian, X; Chen, W; Hicks, K; Kramer, K; Laget, J M; Mibe, T; Qiang, Y; Stepanyan, Syed; Tedeschi, D J; Xu, W; Adhikari, K P; Amaryan, Mak; Anghinolfi, M; Ball, J; Battaglieri, M; Batourine, V; Bedlinskiy, I; Bellis, M; Biselli, A S; Bookwalter, C; Branford, D; Briscoe, W J; Brooks, W K; Burkert, V D; Careccia, S L; Carman, D S; Cole, P L; Collins, P; Crede, V; D& #x27; Angelo, A; Daniel, A; Dashyan, N; De Vita, R; De Sanctis, E; Deur, A; Dey, B; Dhamija, S; Djalali, C; Doughty, D; Dupre, R; Egiyan, H; El Alaoui, A; Eugenio, P; Fegan, S; Gabrielyan, M Y; Gevorgyan, N; Gilfoyle, G P; Giovanetti, K L; Girod, F X; Goetz, J T; Gohn, W; Gothe, R W; Graham, L; Griffioen, K A; Guidal, M; Guo, L; Hafidi, K; Hakobyan, H; Hanretty, C; Hassall, N; Holtrop, M; Ilieva, Y; Ireland, D G; Jawalker, S S; Jo, H S; Joo, K; Keller, D; Khandaker, M; Khetarpal, P; Kim, A; Kim, W; Klein, F J; Konczykowski, P; Kubarovsky, V; Kuleshov, S V; Kuznetsov, V; Livingston, K; Martinez, D; Mayer, M; McAndrew, J; McCracken, M E; McKinnon, B; Meyer, C A; Mikhailov, K; Mineeva, T; Mirazita, M; Mokeev, V; Moreno, B; Moriya, K; Morrison, B; Moutarde, H; Munevar, E; Nadel-Turonski, P; Ni, A; Niccolai, S; Niculescu, I; Niroula, M R; Osipenko, M; Ostrovidov, A I; Paremuzyan, R; Park, K; Park, S; Anefalos Pereira, S; Pisano, S; Pogorelko, O; Pozdniakov, S; Price, J W; Procureur, S; Protopopescu, D; Ricco, G; Ripani, M; Ritchie, B G; Rosner, G; Rossi, P; Sabatie, F; Saini, M S; Salgado, C; Schott, D; Schumacher, R A; Seder, E; Seraydaryan, H; Sharabian, Y G; Smith, E S; Smith, G D; Sober, D I; Sokhan, D; Stepanyan, S S; Stoler, P; Strakovsky, I I; Strauch, S; Taiuti, M; Taylor, C E; Tkachenko, S; Ungaro, M; Vernarsky, B; Vineyard, M F; Voutier, E; Weinstein, L B; Weygand, D P; Wood, M H; Zachariou, N; Zana, L; Zhang, J; Zhao, B

    2011-02-01

    We report the first measurement of the differential cross section on $\\phi$-meson photoproduction from deuterium near the production threshold for a proton using the CLAS detector and a tagged-photon beam in Hall B at Jefferson Lab. The measurement was carried out by a triple coincidence detection of a proton, $K^+$ and $K^-$ near the theoretical production threshold of 1.57 GeV. The extracted differential cross sections $\\frac{d\\sigma}{dt}$ for the initial photon energy from 1.65-1.75 GeV are consistent with predictions based on a quasifree mechanism. This experiment establishes a baseline for a future experimental search for an exotic $\\phi$-N bound state from heavier nuclear targets utilizing subthreshold/near-threshold production of $\\phi$ mesons.

  17. Near-threshold Photoproduction of Phi Mesons from Deuterium

    E-print Network

    X. Qian; W. Chen; H. Gao; K. Hicks; K. Kramer; J. M. Laget; T. Mibe; Y. Qiang; S. Stepanyan; D. J. Tedeschi; W. Xu; K. P. Adhikari; M. Amaryan; M. Anghinolfi; J. Ball; M. Battaglieri; V. Batourine; I. Bedlinskiy; M. Bellis; A. S. Biselli; C. Bookwalter; D. Branford; W. J. Briscoe; W. K. Brooks; V. D. Burkert; S. L. Careccia; D. S. Carman; P. L. Cole; P. Collins; V. Crede; A. D'Angelo; A. Daniel; N. Dashyan; R. De Vita; E. De Sanctis; A. Deur; B. Dey; S. Dhamija; C. Djalali; D. Doughty; R. Dupre; H. Egiyan; A. El Alaoui; P. Eugenio; S. Fegan; M. Y. Gabrielyan; N. Gevorgyan; G. P. Gilfoyle; K. L. Giovanetti; F. X. Girod; J. T. Goetz; W. Gohn; R. W. Gothe; L. Graham; K. A. Griffioen; M. Guidal; L. Guo; K. Hafidi; H. Hakobyan; C. Hanretty; N. Hassall; M. Holtrop; Y. Ilieva; D. G. Ireland; S. S. Jawalkar; H. S. Jo; K. Joo; D. Keller; M. Khandaker; P. Khetarpal; A. Kim; W. Kim; A. Klein; F. J. Klein; P. Konczykowski; V. Kubarovsky; S. V. Kuleshov; V. Kuznetsov; K. Livingston; D. Martinez; M. Mayer; J. McAndrew; M. E. McCracken; B. McKinnon; C. A. Meyer; K. Mikhailov; T. Mineeva; M. Mirazita; V. Mokeev; B. Moreno; K. Moriya; B. Morrison; H. Moutarde; E. Munevar; P. Nadel-Turonski; A. Ni; S. Niccolai; I. Niculescu; M. R. Niroula; M. Osipenko; A. I. Ostrovidov; R. Paremuzyan; K. Park; S. Park; S. Anefalos Pereira; S. Pisano; O. Pogorelko; S. Pozdniakov; J. W. Price; S. Procureur; D. Protopopescu; G. Ricco; M. Ripani; B. G. Ritchie; G. Rosner; P. Rossi; F. Sabatié; M. S. Saini; C. Salgado; D. Schott; R. A. Schumacher; E. Seder; H. Seraydaryan; Y. G. Sharabian; E. S. Smith; G. D. Smith; D. I. Sober; D. Sokhan; S. S. Stepanyan; P. Stoler; I. I. Strakovsky; S. Strauch; M. Taiuti; C. E. Taylor; S. Tkachenko; M. Ungaro; B . Vernarsky; M. F. Vineyard; E. Voutier; L. B. Weinstein; D. P. Weygand; M. H. Wood; N. Zachariou; L. Zana; J. Zhang; B. Zhao; Z. W. Zhao

    2010-12-14

    We report the first measurement of the differential cross section on $\\phi$-meson photoproduction from deuterium near the production threshold for a proton using the CLAS detector and a tagged-photon beam in Hall B at Jefferson Lab. The measurement was carried out by a triple coincidence detection of a proton, $K^+$ and $K^-$ near the theoretical production threshold of 1.57 GeV. The extracted differential cross sections $\\frac{d\\sigma}{dt}$ for the initial photon energy from 1.65-1.75 GeV are consistent with predictions based on a quasifree mechanism. This experiment establishes a baseline for a future experimental search for an exotic $\\phi$-N bound state from heavier nuclear targets utilizing subthreshold/near-threshold production of $\\phi$ mesons.

  18. A two-stage spectrum sensing scheme based on energy detection and a novel multitaper method

    NASA Astrophysics Data System (ADS)

    Qi, Pei-Han; Li, Zan; Si, Jiang-Bo; Xiong, Tian-Yi

    2015-04-01

    Wideband spectrum sensing has drawn much attention in recent years since it provides more opportunities to the secondary users. However, wideband spectrum sensing requires a long time and a complex mechanism at the sensing terminal. A two-stage wideband spectrum sensing scheme is considered to proceed spectrum sensing with low time consumption and high performance to tackle this predicament. In this scheme, a novel multitaper spectrum sensing (MSS) method is proposed to mitigate the poor performance of energy detection (ED) in the low signal-to-noise ratio (SNR) region. The closed-form expression of the decision threshold is derived based on the Neyman–Pearson criterion and the probability of detection in the Rayleigh fading channel is analyzed. An optimization problem is formulated to maximize the probability of detection of the proposed two-stage scheme and the average sensing time of the two-stage scheme is analyzed. Numerical results validate the efficiency of MSS and show that the two-stage spectrum sensing scheme enjoys higher performance in the low SNR region and lower time cost in the high SNR region than the single-stage scheme. Project supported by the National Natural Science Foundation of China (Grant No. 61301179), the China Postdoctoral Science Foundation (Grant No. 2014M550479), and the Doctorial Programs Foundation of the Ministry of Education, China (Grant No. 20110203110011).

  19. Measurements of the photon induced production of $\\Lambda$ in the $^2$H$({\\gamma},{\\Lambda})$X process at threshold energies

    E-print Network

    Beckford, B; Chiba, A; Doi, D; Fujii, T; Fujii, Y; Futatsukawa, K; Gogami, T; Hashimoto, O; Han, Y C; Hirose, K; Hirose, S; Honda, R; Hosomi, K; Ishikawa, T; Kanda, H; Kaneta, M; Kaneko, Y; Kato, S; Kawama, D; Kimura, C; Kiyokawa, S; Koike, T; Maeda, K; Makabe, K; Matsubara, M; Miwa, K; Nagao, S; Nakamura, S N; Okuyama, A; Shirotori, K; Sugihara, K; Suzuki, K; Tamae, T; Tamura, H; Tsukada, K; Yagi, K; Yamamoto, F; Yamamoto, T O; Yamazaki, H; Yonemoto, Y

    2012-01-01

    An experiment was carried out with the NKS2+ in 2010 at the Research Center for Electron Photon Science (ELPH), in which tagged photon beams in the range of 0.8 $\\le$ $E_{\\gamma}$ $\\le$ 1.1 GeV were impinged on a liquid $^2$H target positioned at the center of the NKS2+. The produced $\\Lambda$ was subsequently detected by the $p{\\pi^{-}}$ decay channel. Integrated cross sections of the $^2$H$({\\gamma},{\\Lambda})$X in the angular region of 0.9 $\\le$ $\\cos{\\theta}_{\\Lambda}^{LAB}$ $\\le$ 1.0 was derived and compared with preceding experimental results of the NKS2 collaboration. In addition, the momentum spectra for two photon energy regions were also procured. The ${\\Lambda}$ angle dependent cross sections as a function of the scattering angle in the laboratory system was additionally deduced. We present the latest results on the excitation function of ${\\Lambda}$ photoproduction, the momentum distributions, angular distributions, and polarization.

  20. Measurements of the photon induced production of $?$ in the $^2$H$(?,?)$X process at threshold energies

    E-print Network

    B. Beckford; P. Bydzovsky; A. Chiba; D. Doi; T. Fujii; Y. Fujii; K. Futatsukawa; T. Gogami; O. Hashimoto; Y. C. Han; K. Hirose; S. Hirose; R. Honda; K. Hosomi; T. Ishikawa; H. Kanda; M. Kaneta; Y. Kaneko; S. Kato; D. Kawama; C. Kimura; S. Kiyokawa; T. Koike; K. Maeda; K. Makabe; M. Matsubara; K. Miwa; S. Nagao; S. N. Nakamura; A. Okuyama; K. Shirotori; K. Sugihara; K. Suzuki; T. Tamae; H. Tamura; K. Tsukada; K. Yagi; F. Yamamoto; T. O. Yamamoto; H. Yamazaki; Y. Yonemoto

    2012-10-29

    An experiment was carried out with the NKS2+ in 2010 at the Research Center for Electron Photon Science (ELPH), in which tagged photon beams in the range of 0.8 $\\le$ $E_{\\gamma}$ $\\le$ 1.1 GeV were impinged on a liquid $^2$H target positioned at the center of the NKS2+. The produced $\\Lambda$ was subsequently detected by the $p{\\pi^{-}}$ decay channel. Integrated cross sections of the $^2$H$({\\gamma},{\\Lambda})$X in the angular region of 0.9 $\\le$ $\\cos{\\theta}_{\\Lambda}^{LAB}$ $\\le$ 1.0 was derived and compared with preceding experimental results of the NKS2 collaboration. In addition, the momentum spectra for two photon energy regions were also procured. The ${\\Lambda}$ angle dependent cross sections as a function of the scattering angle in the laboratory system was additionally deduced. We present the latest results on the excitation function of ${\\Lambda}$ photoproduction, the momentum distributions, angular distributions, and polarization.

  1. LAT Perspectives in Detection of High Energy Cosmic Ray Electrons

    NASA Technical Reports Server (NTRS)

    Moiseev, Alexander; Ormes, J. F.; Funk, Stefan

    2007-01-01

    The GLAST Large Area Telescope (LAT) science objectives and capabilities in the detection of high energy electrons in the energy range from 20 GeV to approx. 1 TeV are presented. LAT simulations are used to establish the event selections. It is found that maintaining the efficiency of electron detection at the level of 30% the residual hadron contamination does not exceed 2-3% of the electron flux. LAT should collect approx. ten million of electrons with the energy above 20 GeV for each year of observation. Precise spectral reconstruction with high statistics presents us with a unique opportunity to investigate several important problems such as studying galactic models of IC radiation, revealing the signatures of nearby sources such as high energy cutoff in the electron spectrum, testing the propagation model, and searching for KKDM particles decay through their contribution to the electron spectrum.

  2. Electronic excitation (5?9 eV) in ethylene and some haloethylenes by threshold electron-impact spectroscopy with an improved energy resolution

    NASA Astrophysics Data System (ADS)

    Verhaart, G. J.; Brongersma, H. H.

    1980-11-01

    An improvement of a conventional trochoidal electron monochromator is presented. In trapped-electron spectra the fwhm is now reduced to 100 meV, even in the presence of reactive gases. Electron excitation and resonance processes have been studied in ethylene, fluoroethylene, 1,1-difluoroethylene and chlorotrifluoroethylene. Singlet and triplet levels of the first Rydberg state can be resolved in the threshold spectrum, due to resonance excitation and the improved energy resolution. Vibronic structure is reported in the transition to the 1B 1g state in ethylene. Some optically forbidden valence shell transitions have been discovered around 8.5 eV in 1,1-difluoroethylene and chlorotrifluoroethylene.

  3. Directed energy active illumination for near-Earth object detection

    NASA Astrophysics Data System (ADS)

    Riley, Jordan; Lubin, Philip; Hughes, Gary B.; O'Neill, Hugh; Meinhold, Peter; Suen, Jonathan; Bible, Johanna; Johansson, Isabella E.; Griswold, Janelle; Cook, Brianna

    2014-09-01

    On 15 February 2013, a previously unknown ~20 m asteroid struck Earth near Chelyabinsk, Russia, releasing kinetic energy equivalent to ~570 kt TNT. Detecting objects like the Chelyabinsk impactor that are orbiting near Earth is a difficult task, in part because such objects spend much of their own orbits in the direction of the Sun when viewed from Earth. Efforts aimed at protecting Earth from future impacts will rely heavily on continued discovery. Ground-based optical observatory networks and Earth-orbiting spacecraft with infrared sensors have dramatically increased the pace of discovery. Still, less than 5% of near-Earth objects (NEOs) >=100 m/~100 Mt TNT have been identified, and the proportion of known objects decreases rapidly for smaller sizes. Low emissivity of some objects also makes detection by passive sensors difficult. A proposed orbiting laser phased array directed energy system could be used for active illumination of NEOs, enhancing discovery particularly for smaller and lower emissivity objects. Laser fiber amplifiers emit very narrow-band energy, simplifying detection. Results of simulated illumination scenarios are presented based on an orbiting emitter array with specified characteristics. Simulations indicate that return signals from small and low emissivity objects is strong enough to detect. The possibility for both directed and full sky blind surveys is discussed, and the resulting diameter and mass limits for objects in different observational scenarios. The ability to determine both position and speed of detected objects is also discussed.

  4. Risk Algorithm Using Serial Biomarker Measurements Doubles the Number of Screen-Detected Cancers Compared With a Single-Threshold Rule in the United Kingdom Collaborative Trial of Ovarian Cancer Screening

    PubMed Central

    Menon, Usha; Ryan, Andy; Kalsi, Jatinderpal; Gentry-Maharaj, Aleksandra; Dawnay, Anne; Habib, Mariam; Apostolidou, Sophia; Singh, Naveena; Benjamin, Elizabeth; Burnell, Matthew; Davies, Susan; Sharma, Aarti; Gunu, Richard; Godfrey, Keith; Lopes, Alberto; Oram, David; Herod, Jonathan; Williamson, Karin; Seif, Mourad W.; Jenkins, Howard; Mould, Tim; Woolas, Robert; Murdoch, John B.; Dobbs, Stephen; Amso, Nazar N.; Leeson, Simon; Cruickshank, Derek; Scott, Ian; Fallowfield, Lesley; Widschwendter, Martin; Reynolds, Karina; McGuire, Alistair; Campbell, Stuart; Parmar, Mahesh; Skates, Steven J.; Jacobs, Ian

    2015-01-01

    Purpose Cancer screening strategies have commonly adopted single-biomarker thresholds to identify abnormality. We investigated the impact of serial biomarker change interpreted through a risk algorithm on cancer detection rates. Patients and Methods In the United Kingdom Collaborative Trial of Ovarian Cancer Screening, 46,237 women, age 50 years or older underwent incidence screening by using the multimodal strategy (MMS) in which annual serum cancer antigen 125 (CA-125) was interpreted with the risk of ovarian cancer algorithm (ROCA). Women were triaged by the ROCA: normal risk, returned to annual screening; intermediate risk, repeat CA-125; and elevated risk, repeat CA-125 and transvaginal ultrasound. Women with persistently increased risk were clinically evaluated. All participants were followed through national cancer and/or death registries. Performance characteristics of a single-threshold rule and the ROCA were compared by using receiver operating characteristic curves. Results After 296,911 women-years of annual incidence screening, 640 women underwent surgery. Of those, 133 had primary invasive epithelial ovarian or tubal cancers (iEOCs). In all, 22 interval iEOCs occurred within 1 year of screening, of which one was detected by ROCA but was managed conservatively after clinical assessment. The sensitivity and specificity of MMS for detection of iEOCs were 85.8% (95% CI, 79.3% to 90.9%) and 99.8% (95% CI, 99.8% to 99.8%), respectively, with 4.8 surgeries per iEOC. ROCA alone detected 87.1% (135 of 155) of the iEOCs. Using fixed CA-125 cutoffs at the last annual screen of more than 35, more than 30, and more than 22 U/mL would have identified 41.3% (64 of 155), 48.4% (75 of 155), and 66.5% (103 of 155), respectively. The area under the curve for ROCA (0.915) was significantly (P = .0027) higher than that for a single-threshold rule (0.869). Conclusion Screening by using ROCA doubled the number of screen-detected iEOCs compared with a fixed cutoff. In the context of cancer screening, reliance on predefined single-threshold rules may result in biomarkers of value being discarded. PMID:25964255

  5. Detection of low-energy muons in the stratosphere

    Microsoft Academic Search

    Yu. A. Aleksandrov; V. G. Afanas'ev; K. G. Afanas'ev; E. V. Gorchakov; V. A. Iozenas; I. A. Rubinshtejn; Yu. I. Stozhkov

    1990-01-01

    The authors concisely describe the characteristics of a device designed to detect 25 - 80 MeV muons. The detector is a cylindrical thallium-doped Na I crystal 8 cm in diameter and 8 cm long. We present calculated values of the geometry factor for muons of various energies and for particles that are not stopped by the detector. The authors describe

  6. A thermalization energy analysis of the threshold voltage shift in amorphous indium gallium zinc oxide thin film transistors under simultaneous negative gate bias and illumination

    NASA Astrophysics Data System (ADS)

    Flewitt, A. J.; Powell, M. J.

    2014-04-01

    It has been previously observed that thin film transistors (TFTs) utilizing an amorphous indium gallium zinc oxide (a-IGZO) semiconducting channel suffer from a threshold voltage shift when subjected to a negative gate bias and light illumination simultaneously. In this work, a thermalization energy analysis has been applied to previously published data on negative bias under illumination stress (NBIS) in a-IGZO TFTs. A barrier to defect conversion of 0.65-0.75 eV is extracted, which is consistent with reported energies of oxygen vacancy migration. The attempt-to-escape frequency is extracted to be 106-107 s-1, which suggests a weak localization of carriers in band tail states over a 20-40 nm distance. Models for the NBIS mechanism based on charge trapping are reviewed and a defect pool model is proposed in which two distinct distributions of defect states exist in the a-IGZO band gap: these are associated with states that are formed as neutrally charged and 2+ charged oxygen vacancies at the time of film formation. In this model, threshold voltage shift is not due to a defect creation process, but to a change in the energy distribution of states in the band gap upon defect migration as this allows a state formed as a neutrally charged vacancy to be converted into one formed as a 2+ charged vacancy and vice versa. Carrier localization close to the defect migration site is necessary for the conversion process to take place, and such defect migration sites are associated with conduction and valence band tail states. Under negative gate bias stressing, the conduction band tail is depleted of carriers, but the bias is insufficient to accumulate holes in the valence band tail states, and so no threshold voltage shift results. It is only under illumination that the quasi Fermi level for holes is sufficiently lowered to allow occupation of valence band tail states. The resulting charge localization then allows a negative threshold voltage shift, but only under conditions of simultaneous negative gate bias and illumination, as observed experimentally as the NBIS effect.

  7. A thermalization energy analysis of the threshold voltage shift in amorphous indium gallium zinc oxide thin film transistors under simultaneous negative gate bias and illumination

    SciTech Connect

    Flewitt, A. J., E-mail: ajf@eng.cam.ac.uk [Electrical Engineering Division, Cambridge University, J J Thomson Avenue, Cambridge CB3 0FA (United Kingdom); Powell, M. J. [252, Valley Drive, Kendal LA9 7SL (United Kingdom)

    2014-04-07

    It has been previously observed that thin film transistors (TFTs) utilizing an amorphous indium gallium zinc oxide (a-IGZO) semiconducting channel suffer from a threshold voltage shift when subjected to a negative gate bias and light illumination simultaneously. In this work, a thermalization energy analysis has been applied to previously published data on negative bias under illumination stress (NBIS) in a-IGZO TFTs. A barrier to defect conversion of 0.65–0.75?eV is extracted, which is consistent with reported energies of oxygen vacancy migration. The attempt-to-escape frequency is extracted to be 10{sup 6}?10{sup 7}?s{sup ?1}, which suggests a weak localization of carriers in band tail states over a 20–40?nm distance. Models for the NBIS mechanism based on charge trapping are reviewed and a defect pool model is proposed in which two distinct distributions of defect states exist in the a-IGZO band gap: these are associated with states that are formed as neutrally charged and 2+ charged oxygen vacancies at the time of film formation. In this model, threshold voltage shift is not due to a defect creation process, but to a change in the energy distribution of states in the band gap upon defect migration as this allows a state formed as a neutrally charged vacancy to be converted into one formed as a 2+ charged vacancy and vice versa. Carrier localization close to the defect migration site is necessary for the conversion process to take place, and such defect migration sites are associated with conduction and valence band tail states. Under negative gate bias stressing, the conduction band tail is depleted of carriers, but the bias is insufficient to accumulate holes in the valence band tail states, and so no threshold voltage shift results. It is only under illumination that the quasi Fermi level for holes is sufficiently lowered to allow occupation of valence band tail states. The resulting charge localization then allows a negative threshold voltage shift, but only under conditions of simultaneous negative gate bias and illumination, as observed experimentally as the NBIS effect.

  8. Observational study of erythrocyte protoporphyrin screening test for detecting low lead exposure in children: Impact of lowering the blood lead action threshold

    SciTech Connect

    Parsons, P.J.; Reilly, A.A.; Hussain, A. (New York State Department of Health, Albany (USA))

    1991-02-01

    We examined a retrospective sample of 1800 children on whom both erythrocyte protoporphyrin (EP) and blood lead (BPb) measurements were taken. The primary objective was to ascertain whether EP is a cost-effective screening test for low but increased BPb concentrations and to establish the optimal thresholds. The data did not provide evidence of an EP threshold at low BPb concentrations; however, the data did show a significant age effect. A subset of 500 children for whom both EP and hematocrit data were available showed no correlation between those variables. Age-specific operating characteristic curves, total error, and cost analyses are presented. The latter sets bounds on the relative cost of EP testing, above which only BPb determination should be performed. The implications of these findings are discussed in light of impending changes in U.S. federal guidelines for preventing lead poisoning in young children.

  9. PREFACE: Sixth Symposium on Large TPCs for Low Energy Rare Event Detection

    NASA Astrophysics Data System (ADS)

    Irastorza, Igor G.; Colas, Paul; Giomataris, Ioannis

    2013-10-01

    For the sixth time the International Symposium on large TPCs for Low-Energy Rare-Event Detection has been organized in Paris on 17-19 December 2012. As for the previous conference, we were welcomed in the Astroparticle and Cosmology Laboratory (APC). Around one hundred physicists from all over the world gathered to discuss progress in the dark matter and low-energy neutrino search. The new results from the LHC were also widely discussed. The Higgs discovery at 125 GeV, without any sign of other new heavy particles, does not provide us with any information on the nature of dark mater. Alternatives to the favored SUSY model, in which the role of the WIMP is played by a stable neutralino, predict low mass candidates below a few GeV. Developing low threshold detectors at sub-keV energies becomes mandatory, and interest for Axion or Axion-like particles as dark matter is revived. We have seen increasing activity in the field and new infrastructures for these searches have been developed. We heard news of activities in the Canfranc laboratory in Spain, Jinping in China, SURF in the USA and about the extension project of Fréjus (LSM) laboratory. We would like to thank the organizing and advisory committees as well as the session chairpersons: J Zinn-Justin, G Wormser, D Nygren, G Chardin, F Vannucci, D Attié, T Patzak and S Jullian. I Giomataris, P Colas and I G Irastorza Group picture

  10. Limit on the Detectability of the Energy Scale of Inflation

    NASA Astrophysics Data System (ADS)

    Knox, Lloyd; Song, Yong-Seon

    2002-07-01

    We show that the polarization of the cosmic microwave background can be used to detect gravity waves from inflation if the energy scale of inflation is above 2 x10(sup 15) GeV . These gravity waves generate polarization patterns with a curl, whereas (to first order in perturbation theory) density perturbations do not. The limiting "noise" arises from the second-order generation of curl from density perturbations, or rather residuals from its subtraction. We calculate optimal sky coverage and detectability limits as a function of detector sensitivity and observing time.

  11. A Temporal Model of Level-Invariant, Tone-in-Noise Detection

    ERIC Educational Resources Information Center

    Berg, Bruce G.

    2004-01-01

    Level-invariant detection refers to findings that thresholds in tone-in-noise detection are unaffected by roving-level procedures that degrade energy cues. Such data are inconsistent with ideas that detection is based on the energy passed by an auditory filter. A hypothesis that detection is based on a level-invariant temporal cue is advanced.…

  12. Oral Contribution: varphi-meson photoproduction off the protons by using linearly polarized photons in the mid- to higher-t regimes at threshold energies

    NASA Astrophysics Data System (ADS)

    Salamanca, Julian; Cole, Philip L.

    2009-12-01

    Observables from vector meson photoproduction by linearly-polarized photons can be expressed in term of bilinear combinations of helicity amplitudes parameterized by the Spin Density Matrix Elements (SDMEs). These SDMEs give straightforward relations for understanding the nature of the parity exchange at threshold energies, as well as for extracting signatures of the Okubo-Zweig-Iizuka violation. This paper will show preliminary measurements of SDMEs for vec gammap ? varphip in the photon energy range of 1.7 to 1.9 GeV (momentum transfer squared t range of -1.2 to -0.25 GeV2) and 1.9 to 2.1 GeV (t range of -1.4 to -0.25 GeV2) from the g8b experimental data collected in the summer of 2005 in the Hall B of Jefferson Lab.

  13. Detection and Analysis of Threats to the Energy Sector: DATES

    SciTech Connect

    Alfonso Valdes

    2010-03-31

    This report summarizes Detection and Analysis of Threats to the Energy Sector (DATES), a project sponsored by the United States Department of Energy and performed by a team led by SRI International, with collaboration from Sandia National Laboratories, ArcSight, Inc., and Invensys Process Systems. DATES sought to advance the state of the practice in intrusion detection and situational awareness with respect to cyber attacks in energy systems. This was achieved through adaptation of detection algorithms for process systems as well as development of novel anomaly detection techniques suited for such systems into a detection suite. These detection components, together with third-party commercial security systems, were interfaced with the commercial Security Information Event Management (SIEM) solution from ArcSight. The efficacy of the integrated solution was demonstrated on two testbeds, one based on a Distributed Control System (DCS) from Invensys, and the other based on the Virtual Control System Environment (VCSE) from Sandia. These achievements advance the DOE Cybersecurity Roadmap [DOE2006] goals in the area of security monitoring. The project ran from October 2007 until March 2010, with the final six months focused on experimentation. In the validation phase, team members from SRI and Sandia coupled the two test environments and carried out a number of distributed and cross-site attacks against various points in one or both testbeds. Alert messages from the distributed, heterogeneous detection components were correlated using the ArcSight SIEM platform, providing within-site and cross-site views of the attacks. In particular, the team demonstrated detection and visualization of network zone traversal and denial-of-service attacks. These capabilities were presented to the DistribuTech Conference and Exhibition in March 2010. The project was hampered by interruption of funding due to continuing resolution issues and agreement on cost share for four months in 2008. This resulted in delays in finalizing agreements with commercial partners, and in particular the Invensys testbed was not installed until December 2008 (as opposed to the March 2008 plan). The project resulted in a number of conference presentations and publications, and was well received when presented at industry forums. In spite of some interest on the part of the utility sector, we were unfortunately not able to engage a utility for a full-scale pilot deployment.

  14. Prospects for detecting high-energy neutrinos from Blazars

    NASA Astrophysics Data System (ADS)

    Dermer, C. D.; Atoyan, A.

    2001-08-01

    The measured spectral energy distribution and variability time scale are used to determine the radiation and magneticfield energy densities in the relativistic plasma that forms the gamma-ray emitting jet in the blazar 3C 279. Assuming that protons are accelerated as efficiently as electrons to a maximum energy determined by the size and magnetic field of the emitting region, we calculate the emissivity of neutrinos produced by protons that interact with the external radiation field intercepted by the jet. The external radiation field provides the most important target photons for photomeson production of high-energy neutrinos in flat spectrum radio quasars (FSRQs). Because of photomeson interactions with this field, km2 neutrino telescopes are predicted to detect > ˜ 0.1-1 neutrinos per year from blazars such as 3C 279. BL Lac objects are weaker neutrino sources if, as widely thought, their ?-ray emission is due to Compton-scattered synchrotron (SSC) radiation.

  15. Echo thresholds for reflections from acoustically diffusive architectural surfaces.

    PubMed

    Robinson, Philip W; Walther, Andreas; Faller, Christof; Braasch, Jonas

    2013-10-01

    When sound reflects from an irregular architectural surface, it spreads spatially and temporally. Extensive research has been devoted to prediction and measurement of diffusion, but less has focused on its perceptual effects. This paper examines the effect of temporal diffusion on echo threshold. There are several notable differences between the waveform of a reflection identical to the direct sound and one from an architectural surface. The onset and offset are damped and the energy is spread in time; hence, the reflection response has a lower peak amplitude, and is decorrelated from the direct sound. The perceptual consequences of these differences are previously undocumented. Echo threshold tests are conducted with speech and music signals, using direct sound and a simulated reflection that is either identical to the direct sound or has various degrees of diffusion. Results indicate that for a speech signal, diffuse reflections are less easily detectable as a separate auditory event than specular reflections of the same total energy. For a music signal, no differences are observed between the echo thresholds for reflections with and without temporal diffusion. Additionally, echo thresholds are found to be shorter for speech than for music, and shorter for spatialized than for diotic presentation of signals. PMID:24116414

  16. Prospects for detection of very high-energy emission from GRB in the context of the external shock model

    E-print Network

    A. Galli; L. Piro

    2008-09-01

    The detection of the 100 GeV-TeV emission by a gamma-ray burst (GRB) will provide an unprecedented opportunity to study the nature of the central engine and the interaction between the relativistic flow and the environment of the burst's progenitor. In this paper we show that there are exciting prospects of detecting from the burst by MAGIC high-energy (HE) emission during the early X-ray flaring activity and, later, during the normal afterglow phase. We also identify the best observational strategy, trigger conditions and time period of observation. We determine the expected HE emission from the flaring and afterglow phases of GRBs in the context of the external shock scenario and compare them with the MAGIC threshold. We find that an X-ray flare with the average properties of the class can be detected in the 100 GeV range by MAGIC, provided that zprospects of detecting the late afterglow emission in the same energy range for most of the bursts with z a few cm^-3. In this case, the MAGIC observation shall extend to about 10-20 ks. We provide recipes for tailoring this prediction to the observational properties of each burst,in particular the fluence in the prompt emission and the redshift, thus allowing an almost real time decision procedure to decide whether to continue the follow-up observation of a burst at late times.

  17. Momentum-Transfer-Resolved Electron Energy Loss Spectroscopy of BaBiO3: Anisotropic Dispersion of Threshold Excitation and Optically Forbidden Transition

    NASA Astrophysics Data System (ADS)

    Wang, Y. Y.; Dravid, V. P.; Bulut, N.; Han, P. D.; Klein, M. V.; Schnatterly, S. E.; Zhang, F. C.

    1995-09-01

    Momentum-transfer-resolved electron energy loss spectroscopy of the valence band transitions in BaBiO3 has revealed for the first time that dispersion of the excitation at the optical gap \\(~2 eV\\) and an optically forbidden transition at 4.5 eV are all anisotropic along [100] and [110]. The anisotropic dispersion of the threshold excitation cannot be described by a simple charge density wave picture but can be explained by a small exciton model proposed in this paper. The optically forbidden transition is found to agree well with a proposed molecular orbital model, where the transition is assigned as the excitation from the O 2p? nonbonding states to the empty Bi 6s state.

  18. Near threshold eta meson production in dp collisions

    E-print Network

    Piskor-Ignatowicz, C; Budzanowski, A; Czerwinski, E; Czyzykiewicz, R; Gil, D; Grzonka, D; Janusz, M; Jarczyk, L; Kamys, B; Khoukaz, A; Klaja, P; Majewski, J; Moskal, P; Oelert, W; Przerwa, J; Ritman, J; Rozek, T; Sefzick, T; Siemaszko, M; Smyrski, J; Täschner, A; Winter, P; Wolke, M; Wüstner, P; Zipper, W

    2006-01-01

    Preliminary results of recent measurements of the near threshold eta meson production in the dp-->dp eta reaction are presented. The experiment was performed at the COSY-Juelich accelerator with the use of the COSY-11 detection system. Data were taken for three values of deuteron beam momenta corresponding to excess energies of 3.2, 6.1 and 9.2 MeV. The energy dependence of the total cross section confirms a strong effect of the final state interaction.

  19. A theory for calculating the surface-adsorbate bond dissociation energy from collision-induced desorption threshold measurements

    NASA Astrophysics Data System (ADS)

    Szulczewski, Gregory; Levis, Robert J.

    1993-04-01

    A model is presented for determining the bond dissociation energy, D0, of a surface-adsorbate complex from collision-induced desorption measurements. D0 is calculated from the minimum collision energy required for desorption by correcting for two energy transfer events using a model based on classical mechanics. The model is tested with measurements made for the CH4/Ni{111} system [Beckerle et al., J. Chem. Phys. 93, 4047 (1990)] and a D0 of 118 meV is found.

  20. Characteristic spectrum of very low-energy photoelectron from above-threshold ionization in the tunneling regime.

    PubMed

    Wu, C Y; Yang, Y D; Liu, Y Q; Gong, Q H; Wu, M; Liu, X; Hao, X L; Li, W D; He, X T; Chen, J

    2012-07-27

    We report an experimental and theoretical study of very low-energy photoelectrons in tunneling ionization process from noble gas atoms interacting with ultrashort intense infrared laser pulses. A universal peak structure with electron energy well below 1 eV in the photoelectron spectrum, corresponding to the double-hump structure in the longitudinal momentum distribution, is identified experimentally for all atomic species. Our quantum and semiclassical analysis reveal the role of long-range Coulomb potential in the production of this very low-energy peak structure. PMID:23006081

  1. Near-threshold (7)Li(p,n)(7)Be neutrons on the practical conditions using thick Li-target and Gaussian proton energies for BNCT.

    PubMed

    Kobayashi, Tooru; Hayashizaki, Noriyosu; Katabuchi, Tatsuya; Tanaka, Kenichi; Bengua, Gerard; Nakao, Noriaki; Kosako, Kazuaki

    2014-06-01

    The near threshold (7)Li(p,n)(7)Be neutrons generated by incident proton energy having Gaussian distribution with mean energies from 1.85 to 1.95MeV, were studied as a practical neutron source for BNCT wherein an RFQ accelerator and a thick Li-target are used. Gaussian energy distributions with the standard deviation of 0, 10, 20 and 40keV for mean proton energies from 1.85 to 1.95MeV were surveyed in 0.01MeV increments. A thick liquid Li-target whose dimensions were established in our previous experiments (i.e., 1mm-thick with 50mm width and 50mm length) was considered in this study. The suitable incident proton energy and physical dimensions of Pb layer which serves as a gamma absorber and a Polyethylene layer which is used as a BDE were surveyed by means of the concepts of TPD. Dose distribution were calculated by using MCNP5. A proton beam with mean energy of 1.92MeV and a Gaussian energy distribution with a standard deviation of 20keV at a current of 10mA was selected from the viewpoint of irradiation time and practically achievable proton current. The suitable thicknesses of Pb gamma absorber was estimated to be about 3cm. The estimated thickness of the polyethylene BDE was about 24mm for an ideal proton current of 13mA, and was 18mm for a practical proton current of 10mA. PMID:24491682

  2. Energy resolution of superconducting tunnel diodes in low-energy radiation detection

    Microsoft Academic Search

    V. V. Samedov

    1998-01-01

    In this paper, we obtain an expression for the energy resolution of superconducting tunnel diodes for detection of low-energy\\u000a x-rays. We show that the major contribution to the energy resolution comes from the relative variance of the probability that\\u000a a quasielectron tunnels from one layer to another, which is due to the spatial dependence of the probability of interaction\\u000a between

  3. Post-threshold energy dependence of the cross section for endoergic processes - Vibrational excitation and reactive scattering.

    NASA Technical Reports Server (NTRS)

    Levine, R. D.; Bernstein, R. B.

    1972-01-01

    The essential features of the translational energy dependence or excitation function for two types of endoergic collisional processes are deduced on the basis of information on the inverse, exoergic processes. Microreversibility is conveniently exploited via the symmetric field function, Y(E), which is uniquely determined at a given total energy, E. In the case of the vibrational excitation of diatomic molecules by atomic or molecular impact, use is made of the abundant data on the temperature dependence of the relaxation time.

  4. Detecting special nuclear materials in containers using high-energy gamma rays emitted by fission products

    DOEpatents

    Norman, Eric B. (Oakland, CA); Prussin, Stanley G. (Kensington, CA)

    2007-10-02

    A method and a system for detecting the presence of special nuclear materials in a container. The system and its method include irradiating the container with an energetic beam, so as to induce a fission in the special nuclear materials, detecting the gamma rays that are emitted from the fission products formed by the fission, to produce a detector signal, comparing the detector signal with a threshold value to form a comparison, and detecting the presence of the special nuclear materials using the comparison.

  5. Chemiluminescence Resonance Energy Transfer-based Detection for Microchip Electrophoresis

    PubMed Central

    Huang, Yong; Shi, Ming; Liu, Rongjun

    2010-01-01

    Since the channels in micro- and nanofluidic devices are extremely small, a sensitive detection is required following microchip electrophoresis (MCE). This work describes a highly sensitive and yet universal detection scheme based on chemiluminescence resonance energy transfer (CRET) for MCE. It was found that an efficient CRET occurred between a luminol donor and a CdTe quantum dot (QD) acceptor in the luminol-NaBrO-QD system, and that it was sensitively suppressed by the presence of certain organic compounds of biological interest including biogenic amines and thiols, amino acids, organic acids, and steroids. These findings allowed developing sensitive MCE-CL assays for the tested compounds. The proposed MCE-CL methods showed desired analytical figures of merit such as a wide concentration range of linear response. Detection limits obtained were ~10?9 M for biogenic amines including dopamine and epinephrine, and ~ 10?8 M for biogenic thiols (e.g. glutathione and acetylcysteine), organic acids (i.e. ascorbic acid and uric acid), estrogens, and native amino acids. These were 10 to 1000 times more sensitive than those of previously reported MCE-based methods with chemiluminescence, electrochemical, or laser induced fluorescence detection for quantifying corresponding compounds. To evaluate the applicability of the present MCE-CL method for analyzing real biological samples, it was used to determine amino acids in individual human red blood cells. Nine amino acids including Lys, Ser, Ala, Glu, Trp, etc. were detected. The contents ranged from 3 to 31 amol /cell. The assay proved to be simple, quick, reproducible, and very sensitive. PMID:20121202

  6. Chemiluminescence resonance energy transfer-based detection for microchip electrophoresis.

    PubMed

    Zhao, Shulin; Huang, Yong; Shi, Ming; Liu, Rongjun; Liu, Yi-Ming

    2010-03-01

    Since the channels in micro- and nanofluidic devices are extremely small, a sensitive detection is required following microchip electrophoresis (MCE). This work describes a highly sensitive and yet universal detection scheme based on chemiluminescence resonance energy transfer (CRET) for MCE. It was found that an efficient CRET occurred between a luminol donor and a CdTe quantum dot (QD) acceptor in the luminol-NaBrO-QD system and that it was sensitively suppressed by the presence of certain organic compounds of biological interest including biogenic amines and thiols, amino acids, organic acids, and steroids. These findings allowed developing sensitive MCE-CL assays for the tested compounds. The proposed MCE-CL methods showed desired analytical figures of merit such as a wide concentration range of linear response. Detection limits obtained were approximately 10(-9) M for biogenic amines including dopamine and epinephrine and approximately 10(-8) M for biogenic thiols (e.g., glutathione and acetylcysteine), organic acids (i.e., ascorbic acid and uric acid), estrogens, and native amino acids. These were 10-1000 times more sensitive than those of previously reported MCE-based methods with chemiluminescence, electrochemical, or laser-induced fluorescence detection for quantifying corresponding compounds. To evaluate the applicability of the present MCE-CL method for analyzing real biological samples, it was used to determine amino acids in individual human red blood cells. Nine amino acids, including Lys, Ser, Ala, Glu, Trp, etc., were detected. The contents ranged from 3 to 31 amol/cell. The assay proved to be simple, quick, reproducible, and very sensitive. PMID:20121202

  7. Energy Transfer Based Nanocomposite Scintillator for Radiation Detection

    NASA Astrophysics Data System (ADS)

    Aslam, Soha; Sahi, Sunil; Chen, Wei; Ma, Lun; Kenarangui, Rasool

    2014-09-01

    Scintillators are the materials that emit light upon irradiation with high energy radiation like X-ray or gamma-ray. Inorganic single crystal and organic (plastic and liquid) are the two most used scintillator types. Both of these scintillator kinds have advantages and disadvantages. Inorganic single crystals are expensive and difficult to grow in desire shape and size. Also, single crystal scintillator such as NaI and CsI are very hygroscopic. On the other hand, organic scintillators have low density which limits their applications in gamma spectroscopy. Due to high quantum yield and size dependent emission, nanoparticles have attracted interested in various field of research. Here, we have studies the nanoparticles for radiation detection. We have synthesized nanoparticles of Cerium fluoride (CeF3), Zinc Oxide (ZnO), Cadmium Telluride (CdTe), Copper complex and Zinc sulfide (ZnS). We have used Fluorescence Resonance Energy Transfer (FRET) principle to enhance the luminescence properties of nanocomposite scintillator. Nanocomposites scintillators are structurally characterized with X-ray diffraction (XRD) and Transmission Electron Microscopy (TEM). Optical properties are studied using Photoluminescence, UV-Visible and X-ray. Enhancements in the luminescence are observed under UV and X-ray excitation. Preliminary studies shows nanocomposite scintillators are promising for radiation detection. Scintillators are the materials that emit light upon irradiation with high energy radiation like X-ray or gamma-ray. Inorganic single crystal and organic (plastic and liquid) are the two most used scintillator types. Both of these scintillator kinds have advantages and disadvantages. Inorganic single crystals are expensive and difficult to grow in desire shape and size. Also, single crystal scintillator such as NaI and CsI are very hygroscopic. On the other hand, organic scintillators have low density which limits their applications in gamma spectroscopy. Due to high quantum yield and size dependent emission, nanoparticles have attracted interested in various field of research. Here, we have studies the nanoparticles for radiation detection. We have synthesized nanoparticles of Cerium fluoride (CeF3), Zinc Oxide (ZnO), Cadmium Telluride (CdTe), Copper complex and Zinc sulfide (ZnS). We have used Fluorescence Resonance Energy Transfer (FRET) principle to enhance the luminescence properties of nanocomposite scintillator. Nanocomposites scintillators are structurally characterized with X-ray diffraction (XRD) and Transmission Electron Microscopy (TEM). Optical properties are studied using Photoluminescence, UV-Visible and X-ray. Enhancements in the luminescence are observed under UV and X-ray excitation. Preliminary studies shows nanocomposite scintillators are promising for radiation detection. US Department of Homeland Security.

  8. AUDIBILITY THRESHOLDS OF THE BLUE JAY

    Microsoft Academic Search

    STEVEN M. COHEN; WILLIAM C. STEBBINS; DAVID B. MOODY

    1978-01-01

    The audibility thresholds of two Blue Jays were measured behaviorally using operant conditioning and psychophysical techniques. The jays responded to pure tones between 0.25 and 10 kHz. Their thresholds are similar to those reported for seven other passerines. This indicates that passerines are somewhat less sensitive than man in the detection of sounds in the 1 to 4 kHz range

  9. Prediction-based threshold for medication alert.

    PubMed

    Kawazoe, Yoshimasa; Miyo, Kengo; Kurahashi, Issei; Sakurai, Ryota; Ohe, Kazuhiko

    2013-01-01

    This study presents a prediction-based approach to determine thresholds for a medication alert in a computerized physician order entry. Traditional static thresholds can sometimes lead to physician's alert fatigue or overlook potentially excessive medication even if the doses are belowthe configured threshold. To address this problem, we applied a random forest algorithm to develop a prediction model for medication doses, and applied a boxplot to determine the thresholds based on the prediction results. An evaluation of the eight drugs most frequently causing alerts in our hospital showed that the performances of the prediction were high, except for two drugs. It was also found that using the thresholds based on the predictions would reduce the alerts to a half of those when using the static thresholds. Notably, some cases were detected only by the prediction thresholds. The significance of the thresholds should be discussed in terms of the trade-offs between gains and losses; however, our approach, which relies on physicians' collective experiences, has practical advantages. PMID:23920550

  10. The fluorescence action spectra of some saturated hydrocarbon liquids for excitation energies above and below their ionization thresholds

    SciTech Connect

    Ostafin, A.E.; Lipsky, S. (Department of Chemistry, University of Minnesota, Minneapolis, Minnesota 55455 (United States))

    1993-04-01

    Fluorescence action spectra have been obtained for the neat liquids, [ital cis]-decalin, [ital trans]-decalin, bicyclohexyl, cyclohexane, methylcyclohexane, isobutylcyclohexane, 2,3,4-trimethylpentane, 2,3-dimethylbutane, 3-methylhexane, 3-methylpentane, [ital n]-decane, [ital n]-dodecane, and [ital n]-pentadecane at excitation energies, [epsilon], ranging from their absorption onsets (at ca. 7 eV) to 10.3 eV. For all compounds, with the exception of [ital cis]-decalin, the fluorescence quantum yield is observed to monotonically decline with increasing [epsilon], reaching a minimum value at an energy, [epsilon][sub [ital m

  11. High-field quench behavior and dependence of hot spot temperature on quench detection voltage threshold in a Bi2Sr2CaCu2Ox coil

    NASA Astrophysics Data System (ADS)

    Shen, Tengming; Ye, Liyang; Turrioni, Daniele; Li, Pei

    2015-07-01

    Small insert solenoids have been built using a multifilamentary Ag/Bi2Sr2CaCu2Ox round wire insulated with a mullite sleeve (?100 ?m in thickness) and characterized in background fields to explore the quench behaviors and limits of Bi2Sr2CaCu2Ox superconducting magnets, with an emphasis on assessing the impact of slow normal zone propagation on quench detection. Using heaters of various lengths to initiate a small normal zone, a coil was quenched safely more than 70 times without degradation, with the maximum coil temperature reaching 280 K. Coils withstood a resistive voltage of tens of mV for seconds without quenching, showing the high stability of these coils and suggesting that the quench detection voltage should be greater than 50 mV in order not to falsely trigger protection. The hot spot temperature for the resistive voltage of the normal zone to reach 100 mV increased from ?40–?80 K while increasing the operating wire current density Jo from 89 A mm?2 to 354 A mm?2, whereas for the voltage to reach 1 V, it increased from ?60–?140 K. This shows the increasing negative impact of slow normal zone propagation on quench detection with increasing Jo and the need to limit the quench detection voltage to <1 V. These measurements, coupled with an analytical quench model, were used to assess the impact of the maximum allowable detection voltage and temperature upon quench detection on the quench protection, assuming a limit of the hot spot temperature to <300 K.

  12. Automated detection and delineation of lung tumors in PET-CT volumes using a lung atlas and iterative mean-SUV threshold

    NASA Astrophysics Data System (ADS)

    Ballangan, Cherry; Wang, Xiuying; Eberl, Stefan; Fulham, Michael; Feng, Dagan

    2009-02-01

    Automated segmentation for the delineation of lung tumors with PET-CT is a challenging task. In PET images, primary lung tumors can have varying degrees of tracer uptake, which sometimes does not differ markedly from normal adjacent structures such as the mediastinum, heart and liver. In addition, separation of tumor from adjacent soft tissues and bone in the chest wall is problematic due to limited resolution. For CT, the tumor soft tissue density can be similar to that in the blood vessels and the chest wall; and although CT provides better boundary definition, exact tumor delineation is also difficult when the tumor density is similar to adjacent structures. We propose an innovative automated adaptive method to delineate lung tumors in PET-CT images in conjunction with a lung atlas in which an iterative mean-SUV (Standardized Uptake Value) threshold is used to gradually define the tumor region in PET. Tumor delineation in the CT data is performed using region growing and seeds obtained autonomously from the PET tumor regions. We evaluated our approach in 13 patients with non-small cell lung cancer (NSCLC) and found it could delineate tumors of different size, shape and location, even when when the NSCLC involved the chest wall.

  13. Adaptive threshold-based approach for energy-efficient consolidation of virtual machines in cloud data centers

    Microsoft Academic Search

    Anton Beloglazov; Rajkumar Buyya

    2010-01-01

    The rapid growth in demand for computational power driven by modern service applications combined with the shift to the Cloud computing model have led to the establishment of large-scale virtualized data centers. Such data centers consume enormous amounts of electrical energy resulting in high operating costs and carbon dioxide emissions. Dynamic consolidation of virtual machines (VMs) and switching idle nodes

  14. Low Energy Electron and Nuclear Recoil Thresholds in the DRIFT-II Negative Ion TPC for Dark Matter Searches

    E-print Network

    S. Burgos; E. Daw; J. Forbes; C. Ghag; M. Gold; C. Hagemann; V. A. Kudryavtsev; T. B. Lawson; D. Loomba; P. Majewski; D. Muna; A. St. J. Murphy; S. M. Paling; A. Petkov; S. J. S. Plank; M. Robinson; N. Sanghi; D. P. Snowden-Ifft; N. J. C. Spooner; J. Turk; E. Tziaferi

    2009-03-30

    Understanding the ability to measure and discriminate particle events at the lowest possible energy is an essential requirement in developing new experiments to search for weakly interacting massive particle (WIMP) dark matter. In this paper we detail an assessment of the potential sensitivity below 10 keV in the 1 m^3 DRIFT-II directionally sensitive, low pressure, negative ion time projection chamber (NITPC), based on event-by-event track reconstruction and calorimetry in the multiwire proportional chamber (MWPC) readout. By application of a digital smoothing polynomial it is shown that the detector is sensitive to sulfur and carbon recoils down to 2.9 and 1.9 keV respectively, and 1.2 keV for electron induced events. The energy sensitivity is demonstrated through the 5.9 keV gamma spectrum of 55Fe, where the energy resolution is sufficient to identify the escape peak. The effect a lower energy sensitivity on the WIMP exclusion limit is demonstrated. In addition to recoil direction reconstruction for WIMP searches this sensitivity suggests new prospects for applications also in KK axion searches.

  15. The odderon versus a new threshold

    SciTech Connect

    Kang, K. (Brown Univ., Providence, RI (United States). Dept. of Physics); White, A.R. (Argonne National Lab., IL (United States))

    1991-10-01

    We show that a new threshold model with a threshold close to but below the UA4 energy is compatible with all forward elastic scattering data at high energies including the widely known UA4 measurement of the forward real part of the elastic p{bar p} scattering amplitude and the recent Fermilab Tevatron Collider experiments of the p{bar p} total cross-section. 14 refs.

  16. Low energy electron and nuclear recoil thresholds in the DRIFT-II negative ion TPC for dark matter searches

    Microsoft Academic Search

    S. Burgos; E. Daw; J. Forbes; C. Ghag; M. Gold; C. Hagemann; V. A. Kudryavtsev; T. B. Lawson; D. Loomba; P. Majewski; D. Muna; A. St. J. Murphy; S. M. Paling; A. Petkov; S. J. S. Plank; M. Robinson; N. Sanghi; D. P. Snowden-Ifft; N. J. C. Spooner; J. Turk; E. Tziaferi

    2009-01-01

    Understanding the ability to measure and discriminate particle events at the lowest possible energy is an essential requirement in developing new experiments to search for weakly interacting massive particle (WIMP) dark matter. In this paper we detail an assessment of the potential sensitivity below 10 keV in the 1 m3 DRIFT-II directionally sensitive, low pressure, negative ion time projection chamber

  17. Detecting single-nucleotide polymorphism by single-nucleotide polymorphism interactions in rheumatoid arthritis using a two-step approach with machine learning and a Bayesian threshold least absolute shrinkage and selection operator (LASSO) model.

    PubMed

    González-Recio, Oscar; de Maturana, Evangelina López; Vega, Andrés T; Engelman, Corinne D; Broman, Karl W

    2009-01-01

    The objective of this study was to detect interactions between relevant single-nucleotide polymorphisms (SNPs) associated with rheumatoid arthritis (RA). Data from Problem 1 of the Genetic Analysis Workshop 16 were used. These data consisted of 868 cases and 1,194 controls genotyped with the 500 k Illumina chip. First, machine learning methods were applied for preselecting SNPs. One hundred SNPs outside the HLA region and 1,500 SNPs in the HLA region were preselected using information-gain theory. The software weka was used to reduce colinearity and redundancy in the HLA region, resulting in a subset of 6 SNPs out of 1,500. In a second step, a parametric approach to account for interactions between SNPs in the HLA region, as well as HLA-nonHLA interactions was conducted using a Bayesian threshold least absolute shrinkage and selection operator (LASSO) model incorporating 2,560 covariates. This approach detected some main and interaction effects for SNPs in genes that have previously been associated with RA (e.g., rs2395175, rs660895, rs10484560, and rs2476601). Further, some other SNPs detected in this study may be considered in candidate gene studies. PMID:20018057

  18. Threshold concepts: implications for the management of natural resources

    USGS Publications Warehouse

    Guntenspergen, Glenn R.; Gross, John

    2014-01-01

    Threshold concepts can have broad relevance in natural resource management. However, the concept of ecological thresholds has not been widely incorporated or adopted in management goals. This largely stems from the uncertainty revolving around threshold levels and the post hoc analyses that have generally been used to identify them. Natural resource managers have a need for new tools and approaches that will help them assess the existence and detection of conditions that demand management actions. Recognition of additional threshold concepts include: utility thresholds (which are based on human values about ecological systems) and decision thresholds (which reflect management objectives and values and include ecological knowledge about a system) as well as ecological thresholds. All of these concepts provide a framework for considering the use of threshold concepts in natural resource decision making.

  19. Hadronic ³He production near threshold

    Microsoft Academic Search

    H.-H. Adam; I. Geck; A. Khoukaz; T. Lister; R. Santo; S. Steltenkamp; A. Taeschner; E. Czerwinski; R. Czyzykiewicz; M. Janusz; L. Jarczyk; B. Kamys; P. Klaja; P. Moskal; C. Piskor-Ignatowicz; J. Przerwa; J. Smyrski; D. Grzonka; K. Kilian; W. Oelert

    2007-01-01

    Measurements of meson production in proton-deuteron collisions have been performed using the COSY-11 facility at COSY (Juelich). Results on total and differential cross sections for the pd³He reaction are presented at five excess energies between Q=5.0 and Q=40.6 MeV. The angular distributions show a transition from an almost isotropic emission close to threshold to a highly anisotropic distribution at higher

  20. Frequency and load ratio effects on critical strain energy release rate Gc thresholds of graphite/epoxy composites

    NASA Technical Reports Server (NTRS)

    Adams, Donald F.; Zimmerman, richard S.; Odom, Edwin M.

    1987-01-01

    Graphite/epoxy composite laminates of T300/BP907 and AS6/HST-7 were axial-tension fatigue tested. Tests were conducted at 5 and 10 Hz, and at loading ratios of R = 0.1 and R = 0.5. Edge delamination was monitored as a function of number of fatigue cycles by monitoring stiffness reduction during fatigue testing. Delamination was confirmed and documented using dye-enhanced X-ray and optical photography. Critical strain energy release rates were then calculated. The composites delaminated readily, with loading ratio having a significant influence. Frequency effects were negligible.

  1. Threshold detection of radar signals off the sea surface in non-Gaussian clutter and deterministic interference: II - statistical analysis of ROI surface data

    SciTech Connect

    Middleton, D.

    1996-05-02

    The purpose of this report is to motivate and outline a program of data analysis, for data obtained from radar returns from ocean surfaces perturbed by internal waves and wind-wave interactions. The ultimate aims of this analysis are to provide the appropriate statistics of the signals returned from these ocean surfaces for: (1) use in implementing and evaluating optimum and near-optimum signal processing procedures for detecting and evaluating (i.e., measuring) these internal wave effects and, (2) to provide quantitative physical insight into both the surface scatter and subsurface mechanisms which determine the received radar signals. Here the focus is initially on the needed statistics of the radar returns. These are primarily: (i) the (instantaneous) amplitude and envelope probability densities, (pdf`s) and distributions (PDFS) of the returns and, (ii) analogous statistics for the intensities (associated with the pixel data). Also required are: (iii) space-time covariance data of the returns, for further improvement of detection capabilities. Preliminary evidence and earlier experiments suggest that these data [(i), (ii)] are nongaussian and strongly so at times. This in turn, if not properly taken into account, can greatly degrade signal detection in the usual weak-signal regimes [1],[2].

  2. Effect of dissipation on dynamical fusion thresholds

    SciTech Connect

    Sierk, A.J.

    1986-01-01

    The existence of dynamical thresholds to fusion in heavy nuclei (A greater than or equal to 200) due to the nature of the potential-energy surface is shown. These thresholds exist even in the absence of dissipative forces, due to the coupling between the various collective deformation degrees of freedom. Using a macroscopic model of nuclear shape dynamics, It is shown how three different suggested dissipation mechanisms increase by varying amounts the excitation energy over the one-dimensional barrier required to cause compound-nucleus formation. The recently introduced surface-plus-window dissipation may give a reasonable representation of experimental data on fusion thresholds, in addition to properly describing fission-fragment kinetic energies and isoscalar giant multipole widths. Scaling of threshold results to asymmetric systems is discussed. 48 refs., 10 figs.

  3. Photoionization of polarized ? (4 p, J = 3) atoms near threshold

    Microsoft Academic Search

    S. Schohl; D. Klar; N. A. Cherepkov; I. D. Petrov; K. Ueda; S. Baier; R. Kau; H. Hotop

    1997-01-01

    Using a crossed atomic and laser beams set-up with mass spectrometric ion detection we have studied the photoionization of laser-excited, aligned 0953-4075\\/30\\/3\\/016\\/img2 atoms from the 0953-4075\\/30\\/3\\/016\\/img3 threshold up to photoelectron energies of 0953-4075\\/30\\/3\\/016\\/img4. Absolute cross sections are reported for parallel 0953-4075\\/30\\/3\\/016\\/img5 and perpendicular 0953-4075\\/30\\/3\\/016\\/img6 polarization directions of the linearly polarized exciting and ionizing CW lasers over the range 0953-4075\\/30\\/3\\/016\\/img7. The

  4. Fuzziness of nonverbal courtship communication unblurred by motion energy detection.

    PubMed

    Grammer, K; Honda, M; Juette, A; Schmitt, A

    1999-09-01

    A new method for the assessment of qualitative description of nonverbal behavior (automatic movie analysis) is introduced. This model-free method does not use any assumptions on the structure and organization of nonverbal behavior. Cross-cultural comparison (Germany, Japan) of unobtrusively filmed initial interactions between 2 opposite-sex strangers revealed no consistent courtship repertoire of directly observable behavior categories. Furthermore, an extensive analysis of gaze behavior and speech revealed differences between the countries but also showed no consistent relation to interest. Motion energy detection demonstrated in both cultures that female movement quality score (number of movements, duration, size, speed, and complexity) covaries with female interest. This effect is in concordance with the theory that in early stages of interactions manipulative efforts occur in order to avoid possible deception in high-risk situations. PMID:10510505

  5. MOS Circuitry Would Detect Low-Energy Charged Particles

    NASA Technical Reports Server (NTRS)

    Sinha, Mahadeva; Wadsworth, Mark

    2003-01-01

    Metal oxide semiconductor (MOS) circuits for measuring spatially varying intensities of beams of low-energy charged particles have been developed. These circuits are intended especially for use in measuring fluxes of ions with spatial resolution along the focal planes of mass spectrometers. Unlike prior mass spectrometer focal-plane detectors, these MOS circuits would not be based on ion-induced generation of electrons, and photons; instead, they would be based on direct detection of the electric charges of the ions. Hence, there would be no need for microchannel plates (for ion-to-electron conversion), phosphors (for electron-to-photon conversion), and photodetectors (for final detection) -- components that degrade spatial resolution and contribute to complexity and size. The developmental circuits are based on linear arrays of charge-coupled devices (CCDs) with associated readout circuitry (see figure). They resemble linear CCD photodetector arrays, except that instead of a photodetector, each pixel contains a capacitive charge sensor. The capacitor in each sensor comprises two electrodes (typically made of aluminum) separated by a layer of insulating material. The exposed electrode captures ions and accumulates their electric charges during signal-integration periods.

  6. Thresholds in conservation effectiveness under climate change

    Microsoft Academic Search

    A. Hansen; L. Phillips

    2007-01-01

    We describe a new approach to conservation that derives from the effect of energy on ecosystem properties and then evaluate potential threshold responses of conservation effectiveness under climate change. Many tests of species energy theory provide evidence that species richness varies with measures of energy such as net primary productivity (NPP). Across continents, this relationship is most often unimodal, with

  7. A threshold for dissipative fission

    SciTech Connect

    Thoennessen, M. [Michigan State Univ., East Lansing, MI (United States); Bertsch, G.F. [Washington Univ., Seattle, WA (United States)

    1993-09-21

    The empirical domain of validity of statistical theory is examined as applied to fission data on pre-fission data on pre-fission neutron, charged particle, and {gamma}-ray multiplicities. Systematics are found of the threshold excitation energy for the appearance of nonstatistical fission. From the data on systems with not too high fissility, the relevant phenomenological parameter is the ratio of the threshold temperature T{sub thresh} to the (temperature-dependent) fission barrier height E{sub Bar}(T). The statistical model reproduces the data for T{sub thresh}/E{sub Bar}(T) < 0.26 {plus_minus} 0.05, but underpredicts the multiplicities at higher T{sub thresh}/E{sub Bar}(T) independent of mass and fissility of the systems.

  8. Star Formation Thresholds

    NASA Astrophysics Data System (ADS)

    Schaye, Joop

    2008-05-01

    To make predictions for the existence of “dark galaxies”, it is necessary to understand what determines whether a gas cloud will form stars. Star formation thresholds are generally explained in terms of the Toomre criterion for gravitational instability. I contrast this theory with the thermo-gravitational instability hypothesis of Schaye (2004), in which star formation is triggered by the formation of a cold gas phase and which predicts a nearly constant surface density threshold. I argue that although the Toomre analysis is useful for the global stability of disc galaxies, it relies on assumptions that break down in the outer regions, where star formation thresholds are observed. The thermo-gravitational instability hypothesis can account for a number of observed phenomena, some of which were thought to be unrelated to star formation thresholds.

  9. Threshold voltage extraction circuit 

    E-print Network

    Hoon, Siew Kuok

    2000-01-01

    A novel optimally self-biasing MOSFET threshold-voltage (V[]) extractor circuit is presented. It implements the most popular industrial extraction algorithm of biasing a saturated MOSFET to the linear portion of its [] versus [] characteristic...

  10. Threshold voltage extraction circuit

    E-print Network

    Hoon, Siew Kuok

    2000-01-01

    A novel optimally self-biasing MOSFET threshold-voltage (V[]) extractor circuit is presented. It implements the most popular industrial extraction algorithm of biasing a saturated MOSFET to the linear portion of its [] versus [] characteristic...

  11. Direct detection rates of dark matter coupled to dark energy

    SciTech Connect

    Tetradis, N. [Department of Physics, University of Athens, Zographou 157 84 (Greece); Vergados, J. D. [Theoretical Physics Division, University of Ioannina, Ioannina, Gr 451 10 (Greece); Institute of Theoretical Physics, University of Tuebingen, Tuebingen (Germany); Faessler, Amand [Institute of Theoretical Physics, University of Tuebingen, Tuebingen (Germany)

    2007-01-15

    We investigate the effect of a coupling between dark matter and dark energy on the rates for the direct detection of dark matter. The magnitude of the effect depends on the strength {kappa} of this new interaction relative to gravity. The resulting isothermal velocity distribution for dark matter in galaxy halos is still Maxwell-Boltzmann (M-B), but the characteristic velocity and the escape velocity are increased by {radical}(1+{kappa}{sup 2}). We adopt a phenomenological approach and consider values of {kappa} near unity. For such values we find that: (i) The (time averaged) event rate increases for light WIMPs, while it is somewhat reduced for WIMP masses larger than 100 GeV. (ii) The time dependence of the rate arising from the modulation amplitude is decreased compared to the standard M-B velocity distribution. (iii) The average and maximum WIMP energy increase proportionally to 1+{kappa}{sup 2}, which, for sufficiently massive WIMPs, allows the possibility of designing experiments measuring {gamma} rays following nuclear de-excitation.

  12. Unimolecular reactions of 1,1,1-trichloroethane, 1,1,1-trichloropropane, and 3,3,3-trifluoro-1,1,1-trichloropropane: determination of threshold energies by chemical activation.

    PubMed

    Turpin, Martha A; Smith, Kylie C; Heard, George L; Setser, D W; Holmes, Bert E

    2014-10-01

    The recombination of CCl3 radicals with CH3, CH3CH2, and CF3CH2 radicals was used to generate CH3CCl3, CH3CH2CCl3, and CF3CH2CCl3 molecules with approximately 87 kcal mol(-1) of vibrational energy in a bath gas at room temperature. The competition between collisional deactivation and unimolecular reaction by HCl elimination was used to obtain the experimental rate constants for each molecule. These experimental rate constants were matched to calculated statistical unimolecular rate constants to assign threshold energies to the three HCl elimination reactions. The models needed for the calculations of the rate constants were obtained from molecular structure calculations using density functional theory (DFT) with the hybrid density-functional MO6-2X recommended by Truhlar for transition states. The assigned threshold energies are 52 ± 2, 50 ± 2, and 52 ± 2 kcal mol(-1) for CH3CCl3, CH3CH2CCl3, and CF3CH2CCl3, respectively, and the CH3 and CF3 groups have only a minor effect on the threshold energies for HCl elimination. The DFT calculated threshold energies are in agreement with the experimentally assigned values. The addition of Cl atoms to the same carbon atom lowers the threshold energy for HCl elimination in the CH3CH2Cl, CH3CHCl2, and CH3CCl3 series. This trend, which is the opposite of that for CH3CH2F, CH3CHF2, and CH3CF3, is discussed in terms of transition-state structure and correlated with the relative stabilities of CH3CH2(+), CH3CHCl(+), and CH3CCl2(+) ions; the relative stabilities are based on the hydride affinities obtained from calculations. Comparison of the reactions of CH3CCl3 and CH2ClCHCl2 shows that the threshold energy is much higher for the isomer with chlorine atoms on both carbon atoms. PMID:25203415

  13. Algorithm for detecting energy diversion. [Appendix contains an annotated bibliography

    SciTech Connect

    Altschul, R.E.; Janky, D.G.; Scholz, F.W.; Tjoelker, R.A.; Tosch, T.J.; Tosch, T.J. (Boeing Computer Services Co., Seattle, WA (United States))

    1991-08-01

    The objective of this project was to investigate those factors influencing energy consumption and to develop advanced statistical algorithms and a corresponding computer program to aid utilities in identifying energy diversion by analyzing patterns of energy consumption and other factors readily available to the utility. This final report documents the development of the algorithms, the methodologies used in analyzing their validity, and the advantages and disadvantages of these methods that resulted from these analyses. In the internal study, the algorithms appear to discriminate diverters from the rest of the population. Problems were found that decreased the efficiency of the algorithms during the field investigation. These included the quality of the data used by the algorithms, and the incomplete description of diverters. For the external study 300 potential diverters were submitted to the participating utility for field investigation. They found many cases of vacancies, seasonal use, two cases of tampering, several of suspect nature, irregularities in billing, and a number of meter problems. The code development was not undertaken due to the inconclusive nature of the results obtained in the external validation of the algorithms. Two final recommendations are presented. The first, to create better profiles for diverters and nondiverters, a large sample investigation of electric utility customers should be conducted. This would eliminate selection bias problems perceived to be present in current data. The second provides a list of action items that can be taken by the utilities, to improve both present detection methods and any algorithms that may be developed in the future. 64 refs., 39 figs., 32 figs.

  14. Prospects for detection of very high-energy emission from GRB in the context of the external shock model

    NASA Astrophysics Data System (ADS)

    Galli, A.; Piro, L.

    2008-10-01

    Context: The detection of the 100 GeV-TeV emission by a gamma-ray burst (GRB) will provide an unprecedented opportunity to study the nature of the central engine and the interaction between the relativistic flow and the environment of the burst's progenitor. Aims: In this paper we show that there are exciting prospects of detecting from the burst by MAGIC high-energy (HE) emission during the early X-ray flaring activity and, later, during the normal afterglow phase. We also identify the best observational strategy: trigger conditions and time period of observation. Methods: We determine the expected HE emission from the flaring and afterglow phases of GRBs in the context of the external shock scenario and compare them with the MAGIC threshold. Results: We find that an X-ray flare with the average properties of the class can be detected in the 100 GeV range by MAGIC, provided that z ? 0.7. The requested observational window with MAGIC should then start from 10-20 s after the burst and cover about 1000-2000 s. Furthermore, we demonstrate that there are solid prospects of detecting the late afterglow emission in the same energy range for most of the bursts with z ? 0.5 if the density of the external medium is n ? a few cm-3. In this case, the MAGIC observation shall extend to about 10-20 ks. We provide recipes for tailoring this prediction to the observational properties of each burst, in particular the fluence in the prompt emission and the redshift, thus allowing an almost real time decision procedure to decide whether to continue the follow-up observation of a burst at late times.

  15. A study of the energy dependence of the detection efficiency of a microchannel plate for low energy H?? ions 

    E-print Network

    Holzscheiter, Karin Elisabeth Martha

    1987-01-01

    molecules versus electron energies [7]. . . . . . The ionization chamber. . . 14 . . 16 Schematic set-up of the ion source. . . . 19 10 Schematic of the gas handling system. . . . . 20 12 Diffusion of hydrogen through different metals [9... voltage (ion energy 700 ev). . . . . . Detection efficiency as a function of H2+ ion energy for different electron energies. . . . . . . . . Measurements of the detection efficiency of channeltrons for H2+ iona [12, 14] . 44 . 46 . 48 . 50 27...

  16. Lucid Dreaming: Reliable Analog Event Detection for Energy-Constrained Applications

    E-print Network

    Lucid Dreaming: Reliable Analog Event Detection for Energy-Constrained Applications Sasha Jevtic vibrations in buildings and bridges, we have designed, implemented, and evaluated lucid dreaming, a hardware

  17. Empirical threshold values for quantitative trait mapping

    Microsoft Academic Search

    G. A. Churchill; R. W. Doerge

    1994-01-01

    The detection of genes that control quantitative characters is a problem of great interest to the genetic mapping community. Methods for locating these quantitative trait loci (QTL) relative to maps of genetic markers are now widely used. This paper addresses an issue common to all QTL mapping methods, that of determining an appropriate threshold value for declaring significant QTL effects.

  18. Fibonacci thresholding: signal representation and morphological filters

    NASA Astrophysics Data System (ADS)

    Grigoryan, Artyom M.; Agaian, Sos S.

    2014-02-01

    A new weighted thresholding concept is presented, which is used for the set-theoretical representation of signals, the producing new signals containing a large number of key features that are in the original signals and the design new morphological filters. Such representation maps many operations of non binary signal and image processing to the union of the simple operations over the binary signals and images. The weighted thresholding is invariant under the morphological transformations, including the basic ones, erosion and dilation. The main idea of using the weighted thresholding is in the choice of the special level of thresholding on which we can concentrate all our attention for the future processing. Together with arithmetical thresholding the so-called Fibonacci levels are chosen because of many interesting properties; one of them is the effective decomposition of the median filter. Experimental results show that the Fibonacci thresholding is much promised and can be used for many applications, including the image enhancement, segmentation, and edge detection.

  19. Measurement of the 13C(?, n)16O reaction at astrophysical energies using the Trojan Horse Method. Focus on the -3 keV sub-threshold resonance

    NASA Astrophysics Data System (ADS)

    La Cognata, M.; Spitaleri, C.; Trippella, O.; Kiss, G. G.; Rogachev, G. V.; Mukhamedzhanov, A. M.; Avila, M.; Guardo, G. L.; Koshchiy, E.; Kuchera, A.; Lamia, L.; Puglia, S. M. R.; Romano, S.; Santiago, D.; Spartà, R.

    2014-03-01

    Most of the nuclei in the mass range 90 ? A ? 208 are produced through the so-called s-process, namely through a series of neutron capture reactions on seed nuclei followed by ?-decays. The 13C(?, n)16O reaction is the neutron source for the main component of the s-process. It is active inside the helium-burning shell of asymptotic giant branch stars, at temperatures ? 108 K, corresponding to an energy interval of 140 - 230 keV. In this region, the astrophysical S(E)-factor is dominated by the -3 keV sub-threshold resonance due to the 6.356 MeV level in 17O. Direct measurements could not soundly establish its contribution owing to the cross section suppression at astrophysical energies determined by the Coulomb barrier between interacting nuclei. Indirect measurements and extrapolations yielded inconsistent results, calling for further investigations. The Trojan Horse Method turns out to be very suited for the study of the 13C(?, n)16O reaction as it allows us to access the low as well as the negative energy re- gion, in particular in the case of resonance reactions. We have applied the Trojan HorseMethod to the 13C(6Li, n16O)d quasi-free reaction. By using the modified R-matrix approach, the asymptotic normalization coefficient {( {tilde C{? 13{{C}}}17{{O(1/}{{{2}}{ + }}{{)}}}} )^2} of the 6.356 MeV level has been deduced as well as the n-partial width, allowing to attain an unprecedented accuracy for the 13C(?, n)16O astrophysical factor. A preliminary analysis of a partial data set has lead to {( {tilde C{? 13{{C}}}17{{O(1/}{{{2}}{ + }}{{)}}}} )^2} = 6.7 - 0.6 + 0.9 {{f}}{{{m}} - 1}, slightly larger than the values in the literature, determining a 13C(?, n)16O reaction rate in agreement with the most results in the literature at ˜ 108 K, with enhanced accuracy thanks to this innovative approach.

  20. Direct measurement of the energy thresholds to conformational isomerization. II. 3-indole-propionic acid and its water-containing complex

    NASA Astrophysics Data System (ADS)

    Clarkson, Jasper R.; Baquero, Esteban; Zwier, Timothy S.

    2005-06-01

    The methods of stimulated emission pumping-hole-filling spectroscopy (SEP-HFS) and population transfer spectroscopy (SEP-PTS) were used to place direct experimental bounds on the energetic barriers to conformational isomerization in 3-indole-propionic acid (IPA) and its water-containing complex. By contrast with tryptamine (Paper I), IPA has only two conformations with significant population in them. The structures of the two conformers are known from previous work [P. M. Felker, J. Phys. Chem. 96, 7844 (1992)]. The energy thresholds for A ?B and B ?A isomerizations are placed at 854 and 754cm-1, respectively. Lower bounds on the isomerization barrier in the two directions are determined from the last transition not observed in the SEP-PT spectra. These are placed at 800 and 644cm-1 for A?B and B ?A, respectively. The combined results place bounds on the relative energies of the A and B minima, with E(B )-E(A)=46-210cm-1. Like the IPA monomer, the IPA-H2O complex forms two conformational isomers. Both these isomers incorporate the water molecule as a bridge between the carbonyl and OH groups of the carboxylic acid. Previous rotational coherence measurements (L. L. Connell, Ph.D. thesis, UCLA, 1991) have determined that these complexes retain the same IPA conformational structure as the monomers. SEP-PTS and SEP-HFS were carried out on the IPA-H2O complexes. It was demonstrated that it is possible to use SEP to drive conformational isomerization between the two conformational isomers of IPA-H2O. Bounds on the energy barriers to conformational isomerization are not effected greatly by the presence of the water molecule, with Ebarrier(A?B)=771-830cm-1 and Ebarrier(B?A)=583-750cm-1. This is a simple consequence of the fact that the barrier is an intramolecular barrier, and the water molecule is held fixed in the COOH pocket, where it interacts with the ring only peripherally during the isomerization process. Finally, changes in the SEP-PT spectral intensity in transitions near the top of the barrier to isomerization as a function of the position of SEP excitation relative to the pulsed valve exit provide some insight to the competition between vibrational relaxation and isomerization in a molecule the size of IPA.

  1. Measurement of the Proton + Proton Going to Proton + Proton + Neutral Pion Cross-Section Near Threshold

    NASA Astrophysics Data System (ADS)

    Ross, M. Alan

    1991-02-01

    The first nuclear physics experiment at the IUCF Cooler is a measurement of the p+ptop+p+ pi^0 cross section near threshold. The Cooler, together with a thin internal H_2 gas jet target, allows for a precise cross section measurement by providing well-defined interaction energies and by eliminating background from p-nucleus pion production which has a much lower threshold. A cylindrically symmetric detector system has been installed in one of the straight sections of the ring and is used to detect the coincident protons in the exit channel with good energy and angular resolution. The mass of the unobserved is then deduced. Elastically scattered protons were detected at the same time and by the same detector as pion production events. Elastic scattering was used for normalization to obtain an absolute p+p top+p+pi^0 cross section.

  2. Near threshold fatigue testing

    SciTech Connect

    Freeman, D.C.; Strum, M.J.

    1993-01-01

    Measurement of the near-threshold fatigue crack growth rate (FCGR) behavior provides a basis for the design and evaluation of components subjected to high cycle fatigue. Typically, the near-threshold fatigue regime describes crack growth rates below approximately 10{sup {minus}5} mm/cycle (4{times}10{sup {minus}7} inch/cycle). One such evaluation was recently performed by the authors for the binary alloy U-6Nb. The procedures developed for this evaluation are described in detail here to provide a general test method for near-threshold FCGR testing. In particular, we describe techniques for high-resolution measurements of crack length performed in-situ through a direct current, potential drop (DCPD) apparatus, and a method which eliminates crack closure effects through the use of loading cycles with constant maximum stress intensity.

  3. Near threshold fatigue testing

    SciTech Connect

    Freeman, D.C.; Strum, M.J.

    1993-01-01

    Measurement of the near-threshold fatigue crack growth rate (FCGR) behavior provides a basis for the design and evaluation of components subjected to high cycle fatigue. Typically, the near-threshold fatigue regime describes crack growth rates below approximately 10[sup [minus]5] mm/cycle (4[times]10[sup [minus]7] inch/cycle). One such evaluation was recently performed by the authors for the binary alloy U-6Nb. The procedures developed for this evaluation are described in detail here to provide a general test method for near-threshold FCGR testing. In particular, we describe techniques for high-resolution measurements of crack length performed in-situ through a direct current, potential drop (DCPD) apparatus, and a method which eliminates crack closure effects through the use of loading cycles with constant maximum stress intensity.

  4. Melanin microcavitation threshold in the near infrared

    NASA Astrophysics Data System (ADS)

    Schmidt, Morgan S.; Kennedy, Paul K.; Vincelette, Rebecca L.; Schuster, Kurt J.; Noojin, Gary D.; Wharmby, Andrew W.; Thomas, Robert J.; Rockwell, Benjamin A.

    2014-02-01

    Thresholds for microcavitation of isolated bovine and porcine melanosomes were determined using single nanosecond (ns) laser pulses in the NIR (1000 - 1319 nm) wavelength regime. Average fluence thresholds for microcavitation increased non-linearly with increasing wavelength. Average fluence thresholds were also measured for 10-ns pulses at 532 nm, and found to be comparable to visible ns pulse values published in previous reports. Fluence thresholds were used to calculate melanosome absorption coefficients, which decreased with increasing wavelength. This trend was found to be comparable to the decrease in retinal pigmented epithelial (RPE) layer absorption coefficients reported over the same wavelength region. Estimated corneal total intraocular energy (TIE) values were determined and compared to the current and proposed maximum permissible exposure (MPE) safe exposure levels. Results from this study support the proposed changes to the MPE levels.

  5. Detection, Diagnosis and Prognosis: Contribution to the energy challenge: Proceedings of the Meeting of the Mechanical Failures Prevention Group

    NASA Technical Reports Server (NTRS)

    Shives, T. R. (editor); Willard, W. A. (editor)

    1981-01-01

    The contribution of failure detection, diagnosis and prognosis to the energy challenge is discussed. Areas of special emphasis included energy management, techniques for failure detection in energy related systems, improved prognostic techniques for energy related systems and opportunities for detection, diagnosis and prognosis in the energy field.

  6. Detection of Medium-Sized Polycyclic Aromatic Hydrocarbons via Fluorescence Energy Transfer

    PubMed Central

    Serio, Nicole; Prignano, Lindsey; Peters, Sean; Levine, Mindy

    2015-01-01

    Reported herein is the use of proximity-induced non-covalent energy transfer for the detection of medium-sized polycyclic aromatic hydrocarbons (PAHs). This energy transfer occurs within the cavity of ?-cyclodextrin in various aqueous environments, including human plasma and coconut water. Highly efficient energy transfer was observed, and the efficiency of the energy transfer is independent of the concentration of ?-cyclodextrin used, demonstrating the importance of hydrophobic binding in facilitating such energy transfer. Low limits of detection were also observed for many of the PAHs investigated, which is promising for the development of fluorescence-based detection schemes. PMID:25821390

  7. Energy-efficient event detection in 3D wireless sensor networks

    Microsoft Academic Search

    Susumu Toriumi; Yuichi Sei; Shinichi Honiden

    2008-01-01

    Event detection techniques are crucial for environmental monitoring and object tracking applications in wireless sensor networks. Event detection requires sensor readings to be collected from multiple sensors, and as sensors have limited resources, their readings should be retrieved efficiently. Existing aggregation-based event detection methods, however, require all sensors in the network to transmit their readings, which results in high energy

  8. Ionization of water and carbon dioxide molecules by electron impact near threshold

    Microsoft Academic Search

    A. N. Zavilopulo; F. F. Chipev; O. B. Shpenik

    2005-01-01

    A measurement technique is described and relative cross-sections for direct and dissociative ionization of H2O and CO2 molecules by electron impact near the threshold are obtained. The experiment is performed by a setup with mass separation of the ions by a monopole mass spectrometer and their detection by a secondary electron multiplicator. The energy dependencies of the cross-sections for the

  9. Statistical analysis of stochastic resonance in a thresholded detector

    E-print Network

    Wefelmeyer, Wolfgang

    Statistical analysis of stochastic resonance in a thresholded detector Priscilla E. Greenwood be detected if noise is added to the data. The noisy signal must be strong enough to exceed the threshold at least occasionally; but very strong noise tends to drown out the signal. There is an optimal noise level

  10. Frequency Band Analysis for Stress Detection Using a Teager Energy Operator Based Feature*

    E-print Network

    Texas at Dallas, University of

    derived from critical bands frequencies. The new detection framework is evaluated on a military speechFrequency Band Analysis for Stress Detection Using a Teager Energy Operator Based Feature* Mandar A characteristics in specific frequency bands. The framework of the previously derived Tea- ger Energy Operator

  11. + neurobiotin mean spike threshold

    E-print Network

    Wilson, Rachel

    -80 -60 -40 Vm(mV) KCH3SO3 + neurobiotin n=5 KCH3S03 n=16 Kaspartate n=5 Kaspartate + biocytin, and the reversal potential EGABA was determined, along with the spike threshold for that cell. With a KCH3SO3-based the KCH3SO3+neurobiotin internal (supplemental Fig. 2). #12;Supplemental Figure 2. PN odor tuning

  12. Designing Acoustic Thresholds

    Microsoft Academic Search

    Pedro Rebelo; Maarten van Walstijn

    This paper introduces the notion of acoustic thresholds as a metaphor for the design of sound objects. We present an approach to sound design which is based on the idea of intervention rather than creation, actively transforming sound by manipulating the acoustic entity itself. By addressing the acoustic specificity of sound objects, as in physical modelling, and by introducing technological

  13. Undervoltage Breakdown Threshold Criteria

    Microsoft Academic Search

    James Cooley; Edgar Choueiri

    2006-01-01

    Undervoltage breakdown, the process by which a pulse of electrons induces a discharge gap to break down when it is near but has not achieved its self-breakdown conditions, is discussed. Specifically, threshold criteria that determine the number of electrons required to induce breakdown both to glow and arc discharges are presented. Numerical and theoretical predictions of these criteria are compared

  14. Elaborating on Threshold Concepts

    ERIC Educational Resources Information Center

    Rountree, Janet; Robins, Anthony; Rountree, Nathan

    2013-01-01

    We propose an expanded definition of Threshold Concepts (TCs) that requires the successful acquisition and internalisation not only of knowledge, but also its practical elaboration in the domains of applied strategies and mental models. This richer definition allows us to clarify the relationship between TCs and Fundamental Ideas, and to account…

  15. Detecting dark energy with wavelets on the sphere Jason D. McEwen

    E-print Network

    McEwen, Jason

    Detecting dark energy with wavelets on the sphere Jason D. McEwen Astrophysics Group, Cavendish Laboratory, Cambridge CB3 0HE, UK ABSTRACT Dark energy dominates the energy density of our Universe, yet we know very little about its nature and origin. Although strong evidence in support of dark energy

  16. Supply and threshold voltage scaling for low power CMOS

    Microsoft Academic Search

    Ricardo Gonzalez; Benjamin M. Gordon; Mark A. Horowitz

    1997-01-01

    This paper investigates the effect of lowering the supply and threshold voltages on the energy efficiency of CMOS circuits. Using a first-order model of the energy and delay of a CMOS circuit, we show that lowering the supply and threshold voltage is generally advantageous, especially when the transistors are velocity saturated and the nodes have a high activity factor, In

  17. Threshold Monitoring Maps for Under-Water Explosions

    NASA Astrophysics Data System (ADS)

    Arora, N. S.

    2014-12-01

    Hydro-acoustic energy in the 1-100 Hz range from under-water explosions can easily spread for thousands of miles due to the unique properties of the deep sound channel. This channel, aka SOFAR channel, exists almost everywhere in the earth's oceans where the water has at least 1500m depth. Once the energy is trapped in this channel it spreads out cylindrically, and hence experiences very little loss, as long as there is an unblocked path from source to receiver. Other losses such as absorption due to chemicals in the ocean (mainly boric acid and magnesium sulphate) are also quite minimal at these low frequencies. It is not surprising then that the International Monitoring System (IMS) maintains a global network of hydrophone stations listening on this particular frequency range. The overall objective of our work is to build a probabilistic model to detect and locate under-water explosions using the IMS network. A number of critical pieces for this model, such as travel time predictions, are already well known. We are extending the existing knowledge-base by building the remaining pieces, most crucially the models for transmission losses and detection probabilities. With a complete model for detecting under-water explosions we are able to combine it with our existing model for seismic events, NET-VISA. In the conference we will present threshold monitoring maps for explosions in the earth's oceans. Our premise is that explosive sources release an unknown fraction of their total energy into the SOFAR channel, and this trapped energy determines their detection probability at each of the IMS hydrophone stations. Our threshold monitoring maps compute the minimum amount of energy at each location that must be released into the deep sound channel such that there is a ninety percent probability that at least two of the IMS stations detect the event. We will also present results of our effort to detect and locate hydro-acoustic events. In particular, we will show results from a recent under-water volcanic eruption at the Ahyl Seamount (April-May 2014), and compare our work with the current processing, both automated and human, at the IDC.

  18. Threshold properties of a microcavity laser with submicroampere threshold current

    SciTech Connect

    Choquette, K.D.; Hou, H.Q.; Lear, K.L.; Chow, W.W.; Mar, A.; Geib, K.M.; Hammons, B.E.

    1996-02-01

    We report the threshold characteristics of small oxide-confined vertical-cavity surface emitting lasers. Abrupt threshold transitions 105 times the spontaneous emission background are obtained at injection currents as low as 470 nanoampere.

  19. The use of Schottky CdTe detectors for high-energy astronomy: application to the detection plane of the instrument SVOM/ECLAIRs

    NASA Astrophysics Data System (ADS)

    Nasser, G.; Godet, O.; Atteia, J.-L.; Amoros, C.; Barret, D.; Bordon, S.; Cordier, B.; Gevin, O.; Gonzalez, F.; Houret, B.; Lacombe, K.; Mandrou, P.; Marty, W.; Mercier, K.; Pons, R.; Rambaud, D.; Ramon, P.; Rouaix, G.; Waegebaert, V.

    2014-07-01

    Ohmic CdZnTe and CdTe detectors have been successfully used in high-energy missions such as IBIS on-board INTEGRAL and the Swift-BAT in the past two decades. Such detectors provide very good quantum efficiency in the hard X-ray band. For the future generation of hard X-ray coded mask detectors, a higher sensitivity will be required. A way to achieve this is to increase the effective area of the pixilated detection plane, to change the mask pattern and/or the properties of the semi-conductors paving the detection plane. For the future Chinese-French Gamma-ray burst mission SVOM, the GRB trigger camera ECLAIRs will make use of a new type of high-energy detectors, the Schottky CdTe detectors. Such detectors, when reversely biased, are known to present very low leakage current, resulting in lower values of the low-energy threshold (down to 4 keV or less) than for previous missions (i.e. > 10 keV for the Swift-BAT and INTEGRAL/IBIS). Such low values will enable ECLAIRs with a moderate geometrical area of 1024 cm2 and a low-energy threshold of 4 keV to be more sensitive to high-redshift GRBs (emitting mainly in X-rays) than the Swift-BAT with a higher effective area and low-energy threshold. However, the spectral performance of such detectors are known to degrade over time, once polarized, due to the polarization effect that strongly depends on the temperature and the bias voltage applied to the detectors. In this paper, we present an intensive study of the properties of Schottky CdTe detectors as used on SVOM/ECLAIRs such as I-V characteristics, polarization effect, activation energy and low temperature annealing effects. We discuss the implications of these measurements on the use of this type of detectors in future high-energy instruments.

  20. Dark Force Detection in Low Energy e-p Collisions

    E-print Network

    Marat Freytsis; Grigory Ovanesyan; Jesse Thaler

    2009-10-03

    We study the prospects for detecting a light boson X with mass m_X dark force" models. In order to evade direct and indirect constraints, X must have small couplings to the standard model (alpha_X 10 MeV). By comparing the signal and background cross sections for the e- p e+ e- final state, we conclude that dark force detection requires an integrated luminosity of around 1 inverse attobarn, achievable with a forthcoming JLab proposal.

  1. Threshold of the precedence effect in noise

    PubMed Central

    Freyman, Richard L.; Griffin, Amanda M.; Zurek, Patrick M.

    2014-01-01

    Three effects that show a temporal asymmetry in the influence of interaural cues were studied through the addition of masking noise: (1) The transient precedence effect—the perceptual dominance of a leading transient over a similar lagging transient; (2) the ongoing precedence effect—lead dominance with lead and lag components that extend in time; and (3) the onset capture effect—determination by an onset transient of the lateral position of an otherwise ambiguous extended trailing sound. These three effects were evoked with noise-burst stimuli and were compared in the presence of masking noise. Using a diotic noise masker, detection thresholds for stimuli with lead/lag interaural delays of 0/500??s were compared to those with 500/0??s delays. None of the three effects showed a masking difference between those conditions, suggesting that none of the effects is operative at masked threshold. A task requiring the discrimination between stimuli with 500/0 and 0/500??s interaural delays was used to determine the threshold for each effect in noise. The results showed similar thresholds in noise (10–13?dB SL) for the transient and ongoing precedence effects, but a much higher threshold (33?dB SL) for onset capture of an ambiguous trailing sound. PMID:24815272

  2. Wavelet Shrinkage: Unification of Basic Thresholding Functions and Thresholds

    E-print Network

    Paris-Sud XI, Université de

    in a huge number of wavelet based methods for image denoising. In addition, there exist many ways to improveWavelet Shrinkage: Unification of Basic Thresholding Functions and Thresholds Abdourrahmane M. Atto and thresholds used in non- parametric estimation of signals by shrinkage in the wavelet domain. The Soft

  3. Nitrogen threshold experiment

    NASA Technical Reports Server (NTRS)

    Treat, C. L.

    1984-01-01

    In order to obtain data on Earth geologic processes associated with wind erosion, Mar's and Venus' atmospheres were simulated. Experiments were designed to observe the effects of pressure, gravity, and density on sand movement. An experiment designed to test the operator variance was a comparative test between nitrogen and carbon dioxide. Pressure and therefore density was increased until threshold was noted. Threshold was determined at precisely the same densities of the two gases. If viscosity were a contributing factor in grain saltation the effect would be noted at low pressures. The experiment showed no such variance between carbon dioxide and nitrogen runs for low pressure (density). The largest difference in viscosity between carbon dioxide and nitrogen occurs at low pressures (densities).

  4. Detecting defaulters for consumed electric energy with neural network clustering

    Microsoft Academic Search

    I. Petkovic; N. Balaban

    2008-01-01

    There are two main fields in the business activity of electric power industry: electric energy distribution and its collection. The first field includes the building and maintenance of electric power facilities according to the needs of consumers with the appropriate strategy of electric energy distribution in the situations of extremely poor and brisk demand. The second field, electric energy collection

  5. Classification of Energy Consumption in Buildings with Outlier Detection

    E-print Network

    Yao, Xin

    of buildings and increasing demand for improved building comfort levels. Therefore, the energy efficiency efficiency could con- tribute to the reduction of the current energy consumption of buildings by at least 20 are not computationally efficient and do not easily lend themselves to building energy management and control systems

  6. A study of the energy dependence of the detection efficiency of a microchannel plate for low energy H?? ions

    E-print Network

    Holzscheiter, Karin Elisabeth Martha

    1987-01-01

    A STUDY OF THE ENERGY DEPENDENCE OF THE DETECTION EFFICIENCY OF A MICROCHANNEL PLATE FOR LOW ENERGY H2 IONS A Thesis by KARIN ELISABETH MARTHA HOLZSCHEITER Submitted to the Graduate College of Texas A&M University in partial fulfillment... of the requirements for the degree of MASTER OF SCIENCE December 1987 Major Subject: Physics A STUDY OF THE ENERGY DEPENDENCE OF THE DETECTION EFFICIENCY OF A MICROCHANNEL PLATE FOR LOW ENERGY H2 IONS A Thesis by KARIN ELISABETH MARTHA HOLZSCHEITER Approved...

  7. Energy efficient data representation and aggregation with event region detection in wireless sensor networks

    NASA Astrophysics Data System (ADS)

    Banerjee, Torsha

    Unlike conventional networks, wireless sensor networks (WSNs) are limited in power, have much smaller memory buffers, and possess relatively slower processing speeds. These characteristics necessitate minimum transfer and storage of information in order to prolong the network lifetime. In this dissertation, we exploit the spatio-temporal nature of sensor data to approximate the current values of the sensors based on readings obtained from neighboring sensors and itself. We propose a Tree based polynomial REGression algorithm, (TREG) that addresses the problem of data compression in wireless sensor networks. Instead of aggregated data, a polynomial function (P) is computed by the regression function, TREG. The coefficients of P are then passed to achieve the following goals: (i) The sink can get attribute values in the regions devoid of sensor nodes, and (ii) Readings over any portion of the region can be obtained at one time by querying the root of the tree. As the size of the data packet from each tree node to its parent remains constant, the proposed scheme scales very well with growing network density or increased coverage area. Since physical attributes exhibit a gradual change over time, we propose an iterative scheme, UPDATE_COEFF, which obviates the need to perform the regression function repeatedly and uses approximations based on previous readings. Extensive simulations are performed on real world data to demonstrate the effectiveness of our proposed aggregation algorithm, TREG. Results reveal that for a network density of 0.0025 nodes/m2, a complete binary tree of depth 4 could provide the absolute error to be less than 6%. A data compression ratio of about 0.02 is achieved using our proposed algorithm, which is almost independent of the tree depth. In addition, our proposed updating scheme makes the aggregation process faster while maintaining the desired error bounds. We also propose a Polynomial-based scheme that addresses the problem of Event Region Detection (PERD) for WSNs. When a single event occurs, a child of the tree sends a Flagged Polynomial (FP) to its parent, if the readings approximated by it falls outside the data range defining the existing phenomenon. After the aggregation process is over, the root having the two polynomials, P and FP can be queried for FP (approximating the new event region) instead of flooding the whole network. For multiple such events, instead of computing a polynomial corresponding to each new event, areas with same data range are combined by the corresponding tree nodes and the aggregated coefficients are passed on. Results reveal that a new event can be detected by PERD while error in detection remains constant and is less than a threshold of 10%. As the node density increases, accuracy and delay for event detection are found to remain almost constant, making PERD highly scalable. Whenever an event occurs in a WSN, data is generated by closeby sensors and relaying the data to the base station (BS) make sensors closer to the BS run out of energy at a much faster rate than sensors in other parts of the network. This gives rise to an unequal distribution of residual energy in the network and makes those sensors with lower remaining energy level die at much faster rate than others. We propose a scheme for enhancing network Lifetime using mobile cluster heads (CH) in a WSN. To maintain remaining energy more evenly, some energy-rich nodes are designated as CHs which move in a controlled manner towards sensors rich in energy and data. This eliminates multihop transmission required by the static sensors and thus increases the overall lifetime of the WSN. We combine the idea of clustering and mobile CH to first form clusters of static sensor nodes. A collaborative strategy among the CHs further increases the lifetime of the network. Time taken for transmitting data to the BS is reduced further by making the CHs follow a connectivity strategy that always maintain a connected path to the BS. Spatial correlation of sensor data can be further exploited for dynamic channel selection

  8. Measuring the speed of dark: Detecting dark energy perturbations

    NASA Astrophysics Data System (ADS)

    de Putter, Roland; Huterer, Dragan; Linder, Eric V.

    2010-05-01

    The nature of dark energy can be probed not only through its equation of state but also through its microphysics, characterized by the sound speed of perturbations to the dark energy density and pressure. As the sound speed drops below the speed of light, dark energy inhomogeneities increase, affecting both cosmic microwave background and matter power spectra. We show that current data can put no significant constraints on the value of the sound speed when dark energy is purely a recent phenomenon, but can begin to show more interesting results for early dark energy models. For example, the best fit model for current data has a slight preference for dynamics [w(a)?-1], degrees of freedom distinct from quintessence (cs?1), and early presence of dark energy [?de(a?1)?0]. Future data may open a new window on dark energy by measuring its spatial as well as time variation.

  9. Image Denoising Using Wavelet Thresholding

    Microsoft Academic Search

    Lakhwinder Kaur; Savita Gupta; R. C. Chauhan

    2002-01-01

    This paper proposes an adaptive threshold estimation method for image denoising in the wavelet domain based on the generalized Guassian distribution (GGD) modeling of subband coefficients. The proposed method called NormalShrink is computationally more efficient and adaptive because the parameters required for estimating the threshold depend on subband data. The threshold is computed by ?? 2\\/? y where ? and

  10. Making Diagnostic Thresholds Less Arbitrary 

    E-print Network

    Unger, Alexis Ariana

    2012-07-16

    MAKING DIAGNOSTIC THRESHOLDS LESS ARBITRARY A Thesis by ALEXIS ARIANA UNGER Submitted to the Office of Graduate Studies of Texas A&M University in partial fulfillment of the requirements for the degree of MASTER OF SCIENCE... May 2011 Major Subject: Psychology Making Diagnostic Thresholds Less Arbitrary Copyright 2011 Alexis Ariana Unger MAKING DIAGNOSTIC THRESHOLDS LESS ARBITRARY A Thesis by ALEXIS ARIANA...

  11. The Bootstrap in Threshold Regression

    Microsoft Academic Search

    Ping Yu

    2009-01-01

    This paper shows that the nonparametric bootstrap is inconsistent, and the parametric bootstrap is consistent for inference of the threshold point in discontinuous threshold regression. An interesting phenomenon is that the asymptotic nonparametric bootstrap distribution of the threshold point is discrete and depends on the sampling path of the original data. Furthermore, the remedies to the nonparametric bootstrap failure in

  12. In-band spectrum sensing in cognitive radio networks: energy detection or feature detection?

    Microsoft Academic Search

    Hyoil Kim; Kang G. Shin

    2008-01-01

    In a cognitive radio network (CRN), in-band spectrum sens- ing is essential for the protection of legacy spectrum users, with which the presence of primary users (PUs) can be de- tected promptly, allowing secondary users (SUs) to vacate the channels immediately. For in-band sensing, it is impor- tant to meet the detectability requirements, such as the max- imum allowed latency

  13. [Testing method of human body's current threshold for perception based on EEG analysis].

    PubMed

    Wang, Xiaofei; Shi, Lijuan; Li, Dong; Zhao, Xu; Shao, Haiming

    2014-02-01

    Electric and electronic products are required to pass through the certification on electrical safety performance before entering into the market in order to reduce electrical shock and electrical fire so as to protect the safety of people and property. The leakage current is the most important factor in testing the electrical safety performance and the test theory is based on the perception current effect and threshold. The traditional method testing the current threshold for perception only depends on the sensing of the human body and is affected by psychological factors. Some authors filter the effect of subjective sensation by using physiological and psychological statistical algorithm in recent years and the reliability and consistency of the experiment data are improved. We established an experiment system of testing the human hody's current threshold for perception based on EEG feature analysis, and obtained 967 groups of data. We used wavelet packet analysis to detect a wave from EEG, and used FFT to do spectral analysis on alpha wave before and after the current flew through the human body. The study has shown that about 97.72% alpha wave energy changes significantly when electrical stimulation occurs. It is well proved that when the EEG feature identification is applied to test the human body current threshold for perception, and meanwhile alpha wave energy change and human body sensing are used together to confirm if the current flowing through the human body reaches the perception threshold, the measurement of the human body current threshold for perception could be carried out objectively and accurately. PMID:24804476

  14. Detection of Large Acoustic Energy Flux in the Solar Atmosphere

    Microsoft Academic Search

    N. Bello González; M. Franz; V. Martínez Pillet; J. A. Bonet; S. K. Solanki; J. C. del Toro Iniesta; W. Schmidt; A. Gandorfer; V. Domingo; P. Barthol; T. Berkefeld; M. Knoelker

    2010-01-01

    We study the energy flux carried by acoustic waves excited by convective motions at sub-photospheric levels. The analysis of high-resolution spectropolarimetric data taken with IMaX\\/SUNRISE provides a total energy flux of ~6400-7700 W m-2 at a height of ~250 km in the 5.2-10 mHz range, i.e., at least twice the largest energy flux found in previous works. Our estimate lies

  15. A method to detect ultra high energy electrons using earth's magnetic field as a radiator

    NASA Technical Reports Server (NTRS)

    Stephens, S. A.; Balasubrahmanyan, V. K.

    1983-01-01

    It is pointed out that the detection of electrons with energies exceeding a few TeV, which lose energy rapidly through synchrotron and inverse Compton processes, would provide valuable information on the distribution of sources and on the propagation of cosmic rays in the solar neighborhood. However, it would not be possible to measure the energy spectrum beyond a few TeV with any of the existing experimental techniques. The present investigation is, therefore concerned with the possibility of detecting electrons with energies exceeding a few TeV on the basis of the photons emitted through synchrotron radiation in the earth's magnetic field. Attention is given to the synchrotron radiation of electrons in the earth's magnetic field, detector response and energy estimation, and the characteristics of an ideal detector, capable of detecting photons with energies equal to or greater than 20 keV.

  16. Detecting special nuclear materials in suspect containers using high-energy gamma rays emitted by fission products

    DOEpatents

    Norman, Eric B [Oakland, CA; Prussin, Stanley G [Kensington, CA

    2009-05-05

    A method and a system for detecting the presence of special nuclear materials in a suspect container. The system and its method include irradiating the suspect container with a beam of neutrons, so as to induce a thermal fission in a portion of the special nuclear materials, detecting the gamma rays that are emitted from the fission products formed by the thermal fission, to produce a detector signal, comparing the detector signal with a threshold value to form a comparison, and detecting the presence of the special nuclear materials using the comparison.

  17. Detecting special nuclear materials in suspect containers using high-energy gamma rays emitted by fission products

    DOEpatents

    Norman, Eric B. (Oakland, CA); Prussin, Stanley G. (Kensington, CA)

    2009-01-27

    A method and a system for detecting the presence of special nuclear materials in a suspect container. The system and its method include irradiating the suspect container with a beam of neutrons, so as to induce a thermal fission in a portion of the special nuclear materials, detecting the gamma rays that are emitted from the fission products formed by the thermal fission, to produce a detector signal, comparing the detector signal with a threshold value to form a comparison, and detecting the presence of the special nuclear materials using the comparison.

  18. Detecting special nuclear materials in suspect containers using high-energy gamma rays emitted by fission products

    DOEpatents

    Norman, Eric B. (Oakland, CA); Prussin, Stanley G. (Kensington, CA)

    2009-01-06

    A method and a system for detecting the presence of special nuclear materials in a suspect container. The system and its method include irradiating the suspect container with a beam of neutrons, so as to induce a thermal fission in a portion of the special nuclear materials, detecting the gamma rays that are emitted from the fission products formed by the thermal fission, to produce a detector signal, comparing the detector signal with a threshold value to form a comparison, and detecting the presence of the special nuclear materials using the comparison.

  19. Adaptive Thresholding and Parameter Estimation for PPM

    NASA Technical Reports Server (NTRS)

    Arabshahi, Payman; Mulai, Ryan; Yan, Tsun-Yee

    2005-01-01

    A method of adaptive setting of a threshold level for the detection of pulses in a pulse-position modulation (PPM) free-space optical communication system has been developed. In simplified terms, it is desirable to set a threshold value high enough to greatly reduce the probability (PFA as defined below) of erroneously detecting noise as signal pulses but not so high as to greatly reduce the probability (PD as defined below) of detecting any signal pulses that may be present along with noise. In the present method, the threshold level is varied with time, in response to changing conditions in the optical-communication channel, in an effort to maintain a balance between the aforesaid competing requirements. An integral part of this adaptation scheme is a scheme for estimating key parameters of the optical-communication channel in particular, parameters that describe the fading and total attenuation in the channel, and parameters that characterize spreading of pulses by atmospheric and other effects. The method can be implemented by software processing of digitized optoelectronic-detector output, and has been tested by computational simulation. In the first stage of processing by this method, the digitized values of the detector output during noise-only time slots of received PPM symbols are averaged to obtain a background level. This background level is subtracted from the detector output in the hope of reducing or eliminating the noise component in the remaining signal. (This background level should not be confused with the detection threshold, which is computed in the last stage of processing.) Next, the remaining signal - in effect, a vector of pulse samples - is normalized by dividing it by its L1 norm (in general, the L1 norm of a vector is defined as the sum of absolute magnitudes of its orthogonal components).

  20. Energy-Efficient Multihypothesis Activity-Detection for Health-Monitoring Applications

    E-print Network

    Annavaram, Murali

    and heart-rate monitors, our methods detect current participant behaviour ­ specific physical activity to monitoring the movements of overweight children in an effort to gauge physical activity. We specificallyEnergy-Efficient Multihypothesis Activity-Detection for Health-Monitoring Applications Gautam

  1. An Energy Efficient FPGA Hardware Architecture for the Acceleration of OpenCV Object Detection

    E-print Network

    Rose, Jonathan

    An Energy Efficient FPGA Hardware Architecture for the Acceleration of OpenCV Object Detection for the Acceleration of OpenCV Object Detection Braiden Brousseau Master of Applied Science Graduate Department . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12 2.4 OpenCV . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13 2.5 Multi

  2. Energy efficient approach to intruder detection in militarily sensitive border using Wireless sensor Networks

    Microsoft Academic Search

    Varghese Thattil; N Vasantha

    2011-01-01

    Border protection from intrusion has always been difficult and expensive, especially when the terrain is inhospitable. The paper proposes a new energy efficient approach to provide early detection of intrusion using Wireless sensor Networks. The systematically deployed sensor nodes not only detect the intrusion but also help to track them. The method suggests transferring data from inhospitable terrain to a

  3. Unstable Particles near Threshold

    E-print Network

    Dongjin Chway; Tae Hyun Jung; Hyung Do Kim

    2015-02-12

    We explore physics of unstable particles when mother particle mass is around the sum of its daughter particle masses. In this case, the conventional wave function renormalization factor is ill-defined. We propose a simple resolution of the threshold singularity problem which still allows the use of narrow width approximation by defining branching ratio in terms of spectral density. The resonance peak and shape is different for different decay channels and no single decay width can be assigned to the unstable particles. Non-exponential decay happens in all time scales.

  4. Detection of large acoustic energy flux in the solar atmosphere

    E-print Network

    González, N Bello; Pillet, V Martínez; Bonet, J A; Solanki, S K; Iniesta, J C del Toro; Schmidt, W; Gandorfer, A; Domingo, V; Barthol, P; Berkefeld, T; Knölker, M

    2010-01-01

    We study the energy flux carried by acoustic waves excited by convective motions at sub-photospheric levels. The analysis of high-resolution spectropolarimetric data taken with IMaX/Sunrise provides a total energy flux of ~ 6400--7700 Wm$^{-2}$ at a height of ~ 250 km in the 5.2-10 mHz range, i.e. at least twice the largest energy flux found in previous works. Our estimate lies within a factor of 2 of the energy flux needed to balance radiative losses from the chromosphere according to Anderson & Athay (1989) and revives interest in acoustic waves for transporting energy to the chromosphere. The acoustic flux is mainly found in the intergranular lanes but also in small rapidly-evolving granules and at the bright borders, forming dark dots and lanes of splitting granules.

  5. DETECTION OF LARGE ACOUSTIC ENERGY FLUX IN THE SOLAR ATMOSPHERE

    SciTech Connect

    Bello Gonzalez, N.; Franz, M.; Schmidt, W.; Berkefeld, T. [Kiepenheuer-Institut fuer Sonnenphysik, Schoeneckstr. 6, 79110 Freiburg (Germany); MartInez Pillet, V.; Bonet, J. A. [Instituto de Astrofisica de Canarias, Avd. Via Lactea s/n, La Laguna (Spain); Solanki, S. K.; Gandorfer, A.; Barthol, P. [Max-Planck-Institut fuer Sonnensystemforschung, Max-Planck-Strasse 2, 37191 Katlenburg-Lindau (Germany); Del Toro Iniesta, J. C.; Domingo, V. [Instituto de Astrofisica de AndalucIa (CSIC), Apdo. de Correos 3004, 18080 Granada (Spain); Knoelker, M., E-mail: nbello@kis.uni-freiburg.d [High Altitude Observatory, National Center for Atmospheric Research, Boulder, CO 80307 (United States)

    2010-11-10

    We study the energy flux carried by acoustic waves excited by convective motions at sub-photospheric levels. The analysis of high-resolution spectropolarimetric data taken with IMaX/SUNRISE provides a total energy flux of {approx}6400-7700 W m{sup -2} at a height of {approx}250 km in the 5.2-10 mHz range, i.e., at least twice the largest energy flux found in previous works. Our estimate lies within a factor of two of the energy flux needed to balance radiative losses from the chromosphere according to the estimates of Anderson and Athay and revives interest in acoustic waves for transporting energy to the chromosphere. The acoustic flux is mainly found in the intergranular lanes but also in small rapidly evolving granules and at the bright borders, forming dark dots and lanes of splitting granules.

  6. Broken Bar Detection in Synchronous Machines Based Wind Energy Conversion System

    E-print Network

    Rahimian, Mina Mashhadi

    2012-10-19

    BROKEN BAR DETECTION IN SYNCHRONOUS MACHINES BASED WIND ENERGY CONVERSION SYSTEM A Dissertation by MINA MASHHADI RAHIMIAN Submitted to the Office of Graduate Studies of Texas A&M University in partial fulfillment... of the requirements for the degree of DOCTOR OF PHILOSOPHY August 2011 Major Subject: Electrical Engineering BROKEN BAR DETECTION IN SYNCHRONOUS MACHINES BASED WIND ENERGY CONVERSION SYSTEM A Dissertation by MINA MASHHADI RAHIMIAN...

  7. Ignition threshold for impact-generated fires

    NASA Astrophysics Data System (ADS)

    Durda, Daniel D.; Kring, David A.

    2004-08-01

    Widespread fires can be generated after large impact events by atmospheric heating caused by the reaccretion of high-energy, vapor-rich plume material. We examine the threshold irradiance levels necessary for spontaneous and pilot ignition of various types of vegetation and define three specific cases for investigation: (1) 51 kW/m2 for a period of at least 2 min to spontaneously ignite wood; (2) 20 kW/m2 for a period of at least 20 min to ignite wood in the presence of an ignition source; and (3) 28 kW/m2 for a period of at least 1 min to ignite foliage, rotten wood, and forest litter. The threshold ejected plume mass for continent-wide spontaneous ignition of wood is ~2 to 6 × 1015 kg, independent of impact location but dependent on the details of the ejecta speed distribution. The threshold ejected plume mass for global spontaneous ignition of wood is in the range ~1 to 2 × 1016 kg. The threshold plume masses for continent-wide and global fires are very nearly the same for piloted ignition of wood, while the threshold plume masses for continent-wide and global ignition of leaves and forest litter are significantly lower, by a factor of ~2 to 3. Impact craters of at least 85 km diameter are needed to produce continental-scale fires, and craters of ~135 km diameter are needed for global-scale fires.

  8. Coloring geographical threshold graphs

    SciTech Connect

    Bradonjic, Milan [Los Alamos National Laboratory; Percus, Allon [Los Alamos National Laboratory; Muller, Tobias [EINDHOVEN UNIV. OF TECH

    2008-01-01

    We propose a coloring algorithm for sparse random graphs generated by the geographical threshold graph (GTG) model, a generalization of random geometric graphs (RGG). In a GTG, nodes are distributed in a Euclidean space, and edges are assigned according to a threshold function involving the distance between nodes as well as randomly chosen node weights. The motivation for analyzing this model is that many real networks (e.g., wireless networks, the Internet, etc.) need to be studied by using a 'richer' stochastic model (which in this case includes both a distance between nodes and weights on the nodes). Here, we analyze the GTG coloring algorithm together with the graph's clique number, showing formally that in spite of the differences in structure between GTG and RGG, the asymptotic behavior of the chromatic number is identical: {chi}1n 1n n / 1n n (1 + {omicron}(1)). Finally, we consider the leading corrections to this expression, again using the coloring algorithm and clique number to provide bounds on the chromatic number. We show that the gap between the lower and upper bound is within C 1n n / (1n 1n n){sup 2}, and specify the constant C.

  9. Optimising threshold levels for information transmission in binary threshold networks: Independent multiplicative noise on each threshold

    NASA Astrophysics Data System (ADS)

    Zhou, Bingchang; McDonnell, Mark D.

    2015-02-01

    The problem of optimising the threshold levels in multilevel threshold system subject to multiplicative Gaussian and uniform noise is considered. Similar to previous results for additive noise, we find a bifurcation phenomenon in the optimal threshold values, as the noise intensity changes. This occurs when the number of threshold units is greater than one. We also study the optimal thresholds for combined additive and multiplicative Gaussian noise, and find that all threshold levels need to be identical to optimise the system when the additive noise intensity is a constant. However, this identical value is not equal to the signal mean, unlike the case of additive noise. When the multiplicative noise intensity is instead held constant, the optimal threshold levels are not all identical for small additive noise intensity but are all equal to zero for large additive noise intensity. The model and our results are potentially relevant for sensor network design and understanding neurobiological sensory neurons such as in the peripheral auditory system.

  10. In-situ fault detection apparatus and method for an encased energy storing device

    DOEpatents

    Hagen, Ronald A. (Stillwater, MN); Comte, Christophe (Montreal, CA); Knudson, Orlin B. (Vadnais Heights, MN); Rosenthal, Brian (Stillwater, MN); Rouillard, Jean (Saint-Luc, CA)

    2000-01-01

    An apparatus and method for detecting a breach in an electrically insulating surface of an electrically conductive power system enclosure within which a number of series connected energy storing devices are disposed. The energy storing devices disposed in the enclosure are connected to a series power connection. A detector is coupled to the series connection and detects a change of state in a test signal derived from the series connected energy storing devices. The detector detects a breach in the insulating layer of the enclosure by detecting a state change in the test signal from a nominal state to a non-nominal state. A voltage detector detects a state change of the test signals from a nominal state, represented by a voltage of a selected end energy storing device, to a non-nominal state, represented by a voltage that substantially exceeds the voltage of the selected opposing end energy storing device. Alternatively, the detector may comprise a signal generator that produces the test signal as a time-varying or modulated test signal and injects the test signal into the series connection. The detector detects the state change of the time-varying or modulated test signal from a nominal state, represented by a signal substantially equivalent to the test signal, to a non-nominal state, representative by an absence of the test signal.

  11. Cavity boundary detection from sequential echocardiograms using a temporally adaptive multilevel energy function

    Microsoft Academic Search

    N. S. Friedland

    1990-01-01

    The floating, 1-D, cyclic Markov random field (F1DCMRF) energy function (EF) based optimization technique is designed and implemented on a time sequence of echocardiograms to perform cavity boundary detection. Temporal information from the sequence is utilized intelligently through an adaptive multilevel energy function. The weight assigned to the temporal continuity component of the EF is allowed to increase as the

  12. An Energy-Harvesting Sensor Architecture and Toolkit for Building Monitoring and Event Detection

    E-print Network

    Dutta, Prabal

    a new architecture for design- ing building-monitoring focused energy-harvesting sensors. The key control systems in the future, we pro- pose an architecture for developing sensors that direcAn Energy-Harvesting Sensor Architecture and Toolkit for Building Monitoring and Event Detection

  13. A frequency response-generalized modal energy diagnostic method for damage detection of composite laminated plates

    Microsoft Academic Search

    Lie Hu; Jiesheng Jiang

    1993-01-01

    The paper proposes a new frequency response function (FRF)-modal energy diagnostic method for damage detection in composite laminated plates. The method uses FRF as the diagnostic parameter, which is sensitive to the damage and can reflect structural dynamic characteristics. A relationship is derived between the variation of the FRF at different-ordered resonant peaks after damage and the modal energy contribution

  14. Energy efficient sampling for event detection in wireless sensor networks

    Microsoft Academic Search

    Zainul Charbiwala; Younghun Kim; Sadaf Zahedi; Jonathan Friedman; Mani B. Srivastava

    2009-01-01

    ABSTRACT Compressive Sensing (CS) is a recently developed mecha- nism that allows signal acquisition and compression to be performed in one inexpensive step so that the sampling pro- cess itself produces a compressed version of the signal. This signicantly,improves systemic energy eciency,because the average sampling rate can be considerably reduced and ex- plicit compression eliminated. In this paper, we introduce

  15. Oscillatory Threshold Logic

    PubMed Central

    Borresen, Jon; Lynch, Stephen

    2012-01-01

    In the 1940s, the first generation of modern computers used vacuum tube oscillators as their principle components, however, with the development of the transistor, such oscillator based computers quickly became obsolete. As the demand for faster and lower power computers continues, transistors are themselves approaching their theoretical limit and emerging technologies must eventually supersede them. With the development of optical oscillators and Josephson junction technology, we are again presented with the possibility of using oscillators as the basic components of computers, and it is possible that the next generation of computers will be composed almost entirely of oscillatory devices. Here, we demonstrate how coupled threshold oscillators may be used to perform binary logic in a manner entirely consistent with modern computer architectures. We describe a variety of computational circuitry and demonstrate working oscillator models of both computation and memory. PMID:23173034

  16. Low-energy nuclear radiation detection with a silicon photodiode

    Microsoft Academic Search

    Hisao Yamamoto; Satoru Hatakeyama; Toshiyuki Norimura; Takehiko Tsuchiya

    1989-01-01

    A radiation detector was fabricated from a commercial silicon photodiode, after removing its transparent cover cap and surface coating. The window thickness of the detector fabricated was evaluated to be 23 mug\\/cm2. The area of the depletion region was 13.2 mm2 and its depth was estimated to be about 100 mum. The energy resolution (FWHM) was 2.0 keV for conversion

  17. NOSTOS: a spherical TPC to detect low energy neutrinos

    SciTech Connect

    Aune, S.; Colas, P.; Ribas, E. Ferrer; Giomataris, Y.; Irastorza, I. G. [DAPNIA, Centre d'Etudes Nucleaires de Saclay (CEA-Saclay), Gif-sur-Yvette (France); Dolbeau, J.; Gorodetzky, P.; Patzak, T.; Salin, P. [APC, Universite Paris 7 Denis Diderot, Paris (France); Fanourakis, G.; Geralis, T.; Kousouris, K. [National Center for Scientific Research 'Demokritos', Athens (Greece); Gounaris, G. J.; Savvidis, I. [Aristotle University of Thessaloniki (Greece); Lepeltier, V. [Laboratoire de l'Accelerateur Lineaire, Orsay (France); Paschos, E.A. [University of Dortmunt, Dortmunt (Germany); Vergados, J.D. [University of Ioannina, Ioannina (Greece)

    2005-09-08

    A novel low-energy ({approx}few keV) neutrino-oscillation experiment NOSTOS, combining a strong tritium source and a high pressure spherical Time Projection Chamber (TPC) detector 10 m in radius has been recently proposed. The oscillation of neutrinos of such energies occurs within the size of the detector itself, potentially allowing for a very precise (and rather systematics-free) measure of the oscillation parameters, in particular, of the smaller mixing angle {theta}13, which value could be determined for the first time. This detector could also be sensitive to the neutrino magnetic moment and be capable of accurately measure the Weinberg angle at low energy. The same apparatus, filled with high pressure Xenon, exhibits a high sensitivity as a Super Nova neutrino detector with extra galactic sensitivity. The outstanding benefits of the new concept of the spherical TPC will be presented, as well as the issues to be demonstrated in the near future by an ongoing R and D. The very first results of small prototype in operation in Saclay are shown.

  18. Tunnel catch from potential wells and energy detection

    E-print Network

    M. V. Karasev; E. V. Vybornyi

    2014-11-17

    We consider the one-dimensional Schr\\"{o}dinger operator in the semiclassical regime assuming that its double-well potential is the sum of a finite "physically given" well and a square shape probing well whose width or depth can be varied (tuned). We study the dynamics of initial state localized in the physical well. It is shown that if the probing well is not too close to the physical one and if its parameters are specially tuned, then the {\\it tunnel catch effect} appears, i.e. the initial state starts tunneling oscillations between the physical and probing wells. The asymptotic formula for the probability of finding the state in the probing well is obtained. We show that the observation of the tunnel catch effect can be used to determine the energy level of the initial state, and we obtain the corresponding asymptotic formula for the initial state energy. We also calculate the leading term of the tunneling splitting of energy levels in this double well potential.

  19. Can dark energy viscosity be detected with the Euclid survey?

    E-print Network

    Domenico Sapone; Elisabetta Majerotto; Martin Kunz; Bianca Garilli

    2015-05-07

    Recent work has demonstrated that it is important to constrain the dynamics of cosmological perturbations, in addition to the evolution of the background, if we want to distinguish among different models of the dark sector. Especially the anisotropic stress of the (possibly effective) dark energy fluid has been shown to be an important discriminator between modified gravity and dark energy models. In this paper we use approximate analytical solutions of the perturbation equations in the presence of viscosity to study how the anisotropic stress affects the weak lensing and galaxy power spectrum. We then forecast how sensitive the photometric and spectroscopic Euclid surveys will be to both the speed of sound and the viscosity of our effective dark energy fluid when using weak lensing tomography and the galaxy power spectrum. We find that Euclid alone can only constrain models with very small speed of sound and viscosity, while it will need the help of other observables in order to give interesting constraints on models with a sound speed close to one. This conclusion is also supported by the expected Bayes factor between models.

  20. Near-threshold photoproduction of ? mesons from deuterium

    Microsoft Academic Search

    X. Qian; W. Chen; H. Gao; K. Hicks; K. Kramer; J. M. Laget; T. Mibe; Y. Qiang; S. Stepanyan; D. J. Tedeschi; W. Xu; K. P. Adhikari; M. Amaryan; M. Anghinolfi; J. Ball; M. Battaglieri; V. Batourine; I. Bedlinskiy; M. Bellis; A. S. Biselli; C. Bookwalter; D. Branford; W. J. Briscoe; W. K. Brooks; V. D. Burkert; S. L. Careccia; D. S. Carman; P. Collins; V. Crede; A. D'Angelo; N. Dashyan; R. De Vita; E. De Sanctis; A. Deur; B. Dey; S. Dhamija; C. Djalali; D. Doughty; R. Dupre; H. Egiyan; A. El Alaoui; P. Eugenio; S. Fegan; M. Y. Gabrielyan; N. Gevorgyan; G. P. Gilfoyle; K. L. Giovanetti; F. X. Girod; J. T. Goetz; W. Gohn; R. W. Gothe; L. Graham; K. A. Griffioen; M. Guidal; L. Guo; K. Hafidi; H. Hakobyan; C. Hanretty; N. Hassall; M. Holtrop; Y. Ilieva; D. G. Ireland; S. S. Jawalkar; H. S. Jo; K. Joo; D. Keller; M. Khandaker; P. Konczykowski; A. Kim; W. Kim; A. Klein; F. J. Klein; V. Kubarovsky; S. V. Kuleshov; V. Kuznetsov; K. Livingston; D. Martinez; M. Mayer; J. McAndrew; M. E. McCracken; B. McKinnon; C. A. Meyer; K. Mikhailov; T. Mineeva; M. Mirazita; V. Mokeev; B. Moreno; K. Moriya; B. Morrison; H. Moutarde; E. Munevar; P. Nadel-Turonski; A. Ni; S. Niccolai; I. Niculescu; M. R. Niroula; M. Osipenko; A. I. Ostrovidov; R. Paremuzyan; S. Anefalos Pereira; S. Pisano; O. Pogorelko; S. Pozdniakov; J. W. Price; S. Procureur; D. Protopopescu; G. Ricco; M. Ripani; B. G. Ritchie; P. Rossi; F. Sabatié; M. S. Saini; C. Salgado; D. Schott; R. A. Schumacher; E. Seder; H. Seraydaryan; Y. G. Sharabian; E. S. Smith; G. D. Smith; D. I. Sober; P. Stoler; I. I. Strakovsky; S. Strauch; M. Taiuti; C. E. Taylor; S. Tkachenko; M. Ungaro; B. Vernarsky; M. F. Vineyard; E. Voutier; L. B. Weinstein; D. P. Weygand; M. H. Wood; N. Zachariou; L. Zana; J. Zhang; B. Zhao; Z. W. Zhao

    2011-01-01

    We report the first, kinematically-complete measurement of the differential cross section of ?-meson photoproduction from deuterium near the production threshold for a proton using the CLAS detector and a tagged-photon beam in Hall B at Jefferson Lab. The measurement was carried out by a triple coincidence detection of a proton, K+ and K? near the theoretical production threshold of 1.57

  1. Threshold magnitude for Ionospheric TEC response to earthquakes

    NASA Astrophysics Data System (ADS)

    Perevalova, N. P.; Sankov, V. A.; Astafyeva, E. I.; Zhupityaeva, A. S.

    2014-02-01

    We have analyzed ionospheric response to earthquakes with magnitudes of 4.1-8.8 which occurred under quiet geomagnetic conditions in different regions of the world (the Baikal region, Kuril Islands, Japan, Greece, Indonesia, China, New Zealand, Salvador, and Chile). This investigation relied on measurements of total electron content (TEC) variations made by ground-based dual-frequency GPS receivers. To perform the analysis, we selected earthquakes with permanent GPS stations installed close by. Data processing has revealed that after 4.1-6.3-magnitude earthquakes wave disturbances in TEC variations are undetectable. We have thoroughly analyzed publications over the period of 1965-2013 which reported on registration of wave TIDs after earthquakes. This analysis demonstrated that the magnitude of the earthquakes having a wave response in the ionosphere was no less than 6.5. Based on our results and on the data from other researchers, we can conclude that there is a threshold magnitude (near 6.5) below which there are no pronounced earthquake-induced wave TEC disturbances. The probability of detection of post-earthquake TIDs with a magnitude close to the threshold depends strongly on geophysical conditions. In addition, reliable identification of the source of such TIDs generally requires many GPS stations in an earthquake zone. At low magnitudes, seismic energy is likely to be insufficient to generate waves in the neutral atmosphere which are able to induce TEC disturbances observable at the level of background fluctuations.

  2. High Energy Resolution Fluorescence Detection X-Ray Absorption Spectroscopy: Detection of Adsorption Sites in Supported Metal Catalysts

    SciTech Connect

    Tromp, Moniek [University of Southampton, School of Chemistry, Highfield, Southampton, SO17 1BJ (United Kingdom); Bokhoven, Jeroen A. van [Institute for chemical and bioengineering ETH Zurich (Switzerland); Safonova, Olga V.; Glatzel, Pieter [ESRF, Grenoble (France); Groot, Frank M. F. de [Utrecht University, Utrecht (Netherlands); Evans, John [University of Southampton, School of Chemistry, Highfield, Southampton, SO17 1BJ (United Kingdom); Diamond Light Source, Didcot (United Kingdom)

    2007-02-02

    High energy resolution fluorescence detection (HERFD) X-ray adsorption spectroscopy (XAS) is demonstrated as a new tool to identify the geometry of metal adsorption sites and the orbitals involved in bonding. The type of CO adsorption site on a nanoparticular Pt-Al2O3 catalyst is determined. The orbitals involved in the Pt - CO bonding are identified using theoretical FEFF8.0 calculations. In situ application of HERFD XAS is applicable to a large number of catalytic systems and will provide fundamental insights in structure - performance relationships.

  3. A sub-threshold cell library and methodology

    E-print Network

    Kwong, Joyce Y. S. (Joyce Yui Si)

    2006-01-01

    Sub-threshold operation is a compelling approach for energy-constrained applications where speed is of secondary concern, but increased sensitivity to process variation must be mitigated in this regime. With scaling of ...

  4. Status of Radio and Acoustic Detection of Ultra-High Energy Cosmic Neutrinos and a Proposal on Reporting Results

    NASA Astrophysics Data System (ADS)

    Saltzberg, David

    2005-01-01

    Neutrino astronomy offers the possibility to perform extra-galactic observations well beyond the photon absorption cutoff above 5 × 1013 eV. Based on observations of cosmic rays, we already know that astrophysical sources produce particles with at least a million times more energy than this photon cutoff. Once discovered, either the nature of the sources themselves or the cross sections of ultra-high energy neutrinos with terrestrial matter may reveal exotic physical processes that are inaccessible to modern accelerators. Some of these processes may be due to as-yet unknown physics at the grand unification scale or beyond. Neutrino telescopes based on optical techniques currently operating and under construction have apertures measured in several km3-sr. Radio and acoustic detection techniques have been demonstrated in laboratory experiments and are currently used for instrumentation of apertures 10 to 10,000 times larger than optical techniques for neutrinos above 1016 eV. I discuss the status of current and proposed neutrino telescope projects based on these techniques. These telescopes have already ruled out some of the more exotic predictions for neutrino intensity. The upcoming generation of radio-based and acoustic-based detectors should be sensitive to cosmic neutrinos above 1018 eV originating through the so-called GZK process. A comparison of different neutrino telescopes using a common aperture variable shows how they are complementary in the trade-offs of volume versus threshold. I include a proposal for how neutrino telescopes should report their sensitivities to facilitate direct comparisons among them and to allow testing of neutrino brightness models that appear even after publication of the experimental results.

  5. Status of Radio and Acoustic Detection of Ultra-High Energy Cosmic Neutrinos and a Proposal on Reporting Results

    NASA Astrophysics Data System (ADS)

    Saltzberg, David

    2006-03-01

    Neutrino astronomy offers the possibility to perform extra-galactic observations well beyond the photon absorption cutoff above 5 × 1013 eV. Based on observations of cosmic rays, we already know that astrophysical sources produce particles with at least a million times more energy than this photon cutoff. Once discovered, either the nature of the sources themselves or the cross sections of ultra-high energy neutrinos with terrestrial matter may reveal exotic physical processes that are inaccessible to modern accelerators. Some of these processes may be due to as-yet unknown physics at the grand unification scale or beyond. Neutrino telescopes based on optical techniques currently operating and under construction have apertures measured in several km3-sr. Radio and acoustic detection techniques have been demonstrated in laboratory experiments and are currently used for instrumentation of apertures 10 to 10,000 times larger than optical techniques for neutrinos above 1016 eV. I discuss the status of current and proposed neutrino telescope projects based on these techniques. These telescopes have already ruled out some of the more exotic predictions for neutrino intensity. The upcoming generation of radio-based and acoustic-based detectors should be sensitive to cosmic neutrinos above 1018 eV originating through the so-called GZK process. A comparison of different neutrino telescopes using a common aperture variable shows how they are complementary in the trade-offs of volume versus threshold. I include a proposal for how neutrino telescopes should report their sensitivities to facilitate direct comparisons among them and to allow testing of neutrino brightness models that appear even after publication of the experimental results.

  6. Differential equation models for sharp threshold dynamics.

    PubMed

    Schramm, Harrison C; Dimitrov, Nedialko B

    2014-01-01

    We develop an extension to differential equation models of dynamical systems to allow us to analyze probabilistic threshold dynamics that fundamentally and globally change system behavior. We apply our novel modeling approach to two cases of interest: a model of infectious disease modified for malware where a detection event drastically changes dynamics by introducing a new class in competition with the original infection; and the Lanchester model of armed conflict, where the loss of a key capability drastically changes the effectiveness of one of the sides. We derive and demonstrate a step-by-step, repeatable method for applying our novel modeling approach to an arbitrary system, and we compare the resulting differential equations to simulations of the system's random progression. Our work leads to a simple and easily implemented method for analyzing probabilistic threshold dynamics using differential equations. PMID:24184349

  7. INFLUENCE OF MASS ON DISPLACEMENT THRESHOLD

    SciTech Connect

    Setyawan, Wahyu; Selby, A.; Nandipati, Giridhar; Roche, Kenneth J.; Kurtz, Richard J.; Wirth, Brian D.

    2014-12-30

    Molecular dynamics simulations are performed to investigate the effect of mass on displacement threshold energy in Cr, Mo, Fe and W. For each interatomic potential, the mass of the atoms is varied among those metals for a total of 16 combinations. The average threshold energy over all crystal directions is calculated within the irreducible crystal directions using appropriate weighting factors. The weighting factors account for the different number of equivalent directions among the grid points and the different solid angle coverage of each grid point. The grid points are constructed with a Miller index increment of 1/24 for a total of 325 points. For each direction, 10 simulations each with a different primary-knock-on atom are performed. The results show that for each interatomic potential, the average threshold energy is insensitive to the mass; i.e., the values are the same within the standard error. In the future, the effect of mass on high-energy cascades for a given interatomic potential will be investigated.

  8. An experimental comparison of conservative versus optimal collision avoidance warning system thresholds

    Microsoft Academic Search

    M. R Lehto; J. D Papastavrou; T. A Ranney; L. A Simmons

    2000-01-01

    In the distributed signal detection theoretic (DSDT) model, the human operator and the warning mechanism are independent decision makers who work together as a team. The DSDT demonstrates that the optimal warning threshold, in general, differs from the signal detection theoretic (SDT) threshold, which assumes a single decision maker. This prediction was tested in an experiment where drivers received monetary

  9. Detection of Action Potentials in the Presence of Noise Using Phase-Space Techniques

    Microsoft Academic Search

    Christopher Paterson; Richard Curry; Alan Purvis; Simon Johnson

    2008-01-01

    Emerging Bio-engineering fields such as Brain Computer Interfaces, neuroprothesis devices and modeling and simulation of neural networks have led to increased research activity in algorithms for the detection, isolation and classification of Action Potentials (AP) from noisy data trains. Current techniques in the field of 'unsupervised no-prior knowledge' biosignal processing include energy operators, wavelet detection and adaptive thresholding. These tend

  10. Analysis of experimental data on doublet neutron-deuteron scattering at energies below the deuteron-breakup threshold on the basis of the pole approximation of the effective-range function

    SciTech Connect

    Babenko, V. A.; Petrov, N. M. [National Academy of Sciences of Ukraine, Bogolyubov Institute for Theoretical Physics (Ukraine)], E-mail: pet@online.com.ua

    2008-01-15

    On the basis of the Bargmann representation of the S matrix, the pole approximation is obtained for the effective-range function k cot {delta}. This approximation is optimal for describing the neutron-deuteron system in the doublet spin state. The values of r{sub 0} = 412.469 fm and v{sub 2} = -35 495.62 fm{sup 3} for the doublet low-energy parameters of neutron-deuteron scattering and the value of D = 172.678 fm{sup 2} for the respective pole parameter are deduced by using experimental results for the triton binding energy E{sub T}, the doublet neutron-deuteron scattering length a{sub 2}, and van Oers-Seagrave phase shifts at energies below the deuteron-breakup threshold. With these parameters, the pole approximation of the effective-range function provides a highly precise description (the relative error does not exceed 1%) of the doublet phase shift for neutron-deuteron scattering at energies below the deuteron-breakup threshold. Physical properties of the triton in the ground (T) and virtual (v) states are calculated. The results are B{sub v} = 0.608 MeV for the virtuallevel position and C{sub T}{sup 2} = 2.866 and C{sub v}{sup 2} = 0.0586 for the dimensionless asymptotic normalization constants. It is shown that, in the Whiting-Fuda approximation, the values of physical quantities characterizing the triton virtual state are determined to a high precision by one parameter, the doublet neutron-deuteron scattering length a{sub 2}. The effective triton radii in the ground ({rho}{sub T} = 1.711 fm) and virtual ({rho}{sub v} = 74.184 fm) states are calculated for the first time.

  11. Automatic detection of bone fragments in poultry using multi-energy x-rays

    SciTech Connect

    Gleason, Shaun S. (Knoxville, TN); Paulus, Michael J. (Knoxville, TN); Mullens, James A. (Knoxville, TN)

    2002-04-09

    At least two linear arrays of x-ray detectors are placed below a conveyor belt in a poultry processing plant. Multiple-energy x-ray sources illuminate the poultry and are detected by the detectors. Laser profilometry is used to measure the poultry thickness as the x-ray data is acquired. The detector readout is processed in real time to detect the presence of small highly attenuating fragments in the poultry, i.e., bone, metal, and cartilage.

  12. On energy transfer by detection of a tunneling atom

    E-print Network

    A. M. Steinberg

    1999-04-28

    We are in the process of building an experiment to study the tunneling of laser-cooled Rubidium atoms through an optical barrier. A particularly thorny set of questions arises when one considers the possibility of observing a tunneling particle while it is in the ``forbidden'' region. In earlier work, we have discussed how one might probe a tunneling atom ``weakly,'' so as to prevent collapse. Here we make some observations about the implications of a more traditional quantum measurement. Considerations of energy conservation suggest that attempts to observe tunneling atoms will enhance inelastic scattering, but not in a way which can be directly observed. It is possible that attempts to make such measurements may lead to experimentally realizable ``observationally assisted barrier penetration.''

  13. Iterative Thresholding Algorithms Massimo Fornasier

    E-print Network

    for denoising signals and images. When the signal is represented in terms of a suitable basis (for instance a wavelet basis) small coefficients are set to zero and larger coefficients above some threshold] established a varia- tional formulation for denoising by 1 penalization, which results in simple soft-thresholding

  14. Threshold Hypothesis: Fact or Artifact?

    ERIC Educational Resources Information Center

    Karwowski, Maciej; Gralewski, Jacek

    2013-01-01

    The threshold hypothesis (TH) assumes the existence of complex relations between creative abilities and intelligence: linear associations below 120 points of IQ and weaker or lack of associations above the threshold. However, diverse results have been obtained over the last six decades--some confirmed the hypothesis and some rejected it. In this…

  15. Bounds on the quantum satisfiability threshold

    E-print Network

    Sergey Bravyi; Cristopher Moore; Alexander Russell

    2014-09-18

    Quantum k-SAT is the problem of deciding whether there is a n-qubit state which is perpendicular to a set of vectors, each of which lies in the Hilbert space of k qubits. Equivalently, the problem is to decide whether a particular type of local Hamiltonian has a ground state with zero energy. We consider random quantum k-SAT formulas with n variables and m = \\alpha n clauses, and ask at what value of \\alpha these formulas cease to be satisfiable. We show that the threshold for random quantum 3-SAT is at most 3.594. For comparison, convincing arguments from statistical physics suggest that the classical 3-SAT threshold is \\alpha \\approx 4.267. For larger k, we show that the quantum threshold is a constant factor smaller than the classical one. Our bounds work by determining the generic rank of the satisfying subspace for certain gadgets, and then using the technique of differential equations to analyze various algorithms that partition the hypergraph into a collection of these gadgets. Our use of differential equation to establish upper bounds on a satisfiability threshold appears to be novel, and our techniques may apply to various classical problems as well.

  16. Detection of low-energy conversion electrons and location of isomeric states

    SciTech Connect

    Kilcher; Sauvage, J.; Bourgeois, C.; Le Blanc, F.; Oms, J.; Roussiere, B.; Munsch, J.; Obert, J.; Caruette, A.; Ferro, A.; and others

    1987-12-10

    The detection of conversion electrons of short-lived isotopes at ISOCELE has been extended to very low-energy: a special tape-transport system has been built which allows the slowing down of the incoming radioactive ions and the acceleration of the electrons detected on photographic film in a flat magnetic spectrograph. Results have been acquired for the decay of mercury with A = 185, 186, 187, 189, 191, and of platinum with A = 184, and 186. As examples the location of isomeric states deduced from our measurements are given to illustrate the power of high-resolution electron detection.

  17. Early results utilizing high-energy fission product (gamma) rays to detect fissionable material in cargo

    SciTech Connect

    Slaughter, D R; Accatino, M R; Bernstein, A; Church, J A; Descalle, M A; Gosnell, T B; Hall, J M; Loshak, A; Manatt, D R; Mauger, G J; McDowell, M; Moore, T M; Norman, E B; Pohl, B A; Pruet, J A; Petersen, D C; Walling, R S; Weirup, D L; Prussin, S G

    2004-09-30

    A concept for detecting the presence of special nuclear material ({sup 235}U or {sup 239}Pu) concealed in intermodal cargo containers is described. It is based on interrogation with a pulsed beam of 7 MeV neutrons that produce fission events and their {beta}-delayed neutron emission or {beta}-delayed high-energy {gamma}-radiation between beam pulses provide the detection signature. Fission product {beta}-delayed {gamma}-rays above 3 MeV are nearly ten times more abundant than {beta}-delayed neutrons and are distinct from natural radioactivity and from nearly all of the induced activity in a normal cargo. Detector backgrounds and potential interferences with the fission signature radiation have been identified and quantified. An important goal in the US is the detection of nuclear weapons or special nuclear material (SNM) concealed in intermodal cargo containers. This must be done with high detection probability, low false alarm rates, and without impeding commerce, i.e. about one minute for an inspection. The concept for inspection has been described before and its components are now being evaluated. While normal radiations emitted from plutonium may allow its detection, the majority of {sup 235}U {gamma} ray emission is at 186 keV, is readily attenuated by cargo, and thus not a reliable detection signature for passive detection. Delayed neutron detection following a neutron or photon beam pulse has been used successfully to detect lightly or unshielded SNM targets. While delayed neutrons can be easily distinguished from beam neutrons they have relatively low yield in fission, approximately 0.008 per fission in {sup 239}Pu and 0.017 per fission in {sup 235}U, and are rapidly attenuated in hydrogenous materials making that technique unreliable when challenged by thick hydrogenous cargo overburden. They propose detection of {beta}-delayed high-energy {gamma} radiation as a more robust signature characteristic of SNM.

  18. Power threshold for neutral beam current drive

    SciTech Connect

    Politzer, P.A. (General Atomics, San Diego, CA (USA)); Porter, G.D. (Lawrence Livermore National Lab., CA (USA))

    1989-10-02

    For fully noninductive current drive in tokamaks using neutral beams, there is a power and density threshold condition, setting a minimum value for P{sup 3/2}/n{sup 2}. If this condition is not met, stationary state cannot occur, and a tokamak discharge will collapse. This is a consequence of the coupling between current and electron temperature, or between current drive efficiency and energy confinement time. 4 figs.

  19. Hadronic He3eta production near threshold

    Microsoft Academic Search

    H.-H. Adam; I. Geck; A. Khoukaz; T. Lister; R. Santo; S. Steltenkamp; A. Täschner; E. Czerwinski; R. Czyzykiewicz; M. Janusz; L. Jarczyk; B. Kamys; P. Klaja; P. Moskal; C. Piskor-Ignatowicz; J. Przerwa; J. Smyrski; D. Grzonka; K. Kilian; W. Oelert; T. Sefzick; P. Winter; M. Wolke; P. Wüstner; A. Budzanowski; T. Rozek; M. Siemaszko; W. Zipper

    2007-01-01

    Measurements of eta meson production in proton-deuteron collisions have been performed using the COSY-11 facility at COSY (Jülich). Results on total and differential cross sections for the pd-->He3eta reaction are presented at five excess energies between Q=5.0 and Q=40.6 MeV. The angular distributions show a transition from an almost isotropic emission close to threshold to a highly anisotropic distribution at

  20. Research on SiO2 film laser damage threshold

    NASA Astrophysics Data System (ADS)

    Wang, Tao; Yang, Lihong

    2012-10-01

    The high energy laser put forward higher requirements about resistance laser damage ability of thin film on surface of optical component, this makes coating film not only consider the optical parameters of thin films, but also consider the film's laser damage threshold to get the optical system work normally. mainly analyzing factors about effecting the SiO2 thin film's laser damage threshold and researching respectively the SiO2 thin film's optical parameters (such as extinction coefficient, thickness, refractive index and so on) and light sources parameters of testing system (such as laser times of irradiation, pulse width and so on) impact on thin film laser damage threshold. Research shows that thin film optical parameters have little influence on laser damage threshold, testing laser parameters have great influence on laser damage threshold.

  1. Boron-layer silicon photodiodes for high-efficiency low-energy electron detection Agata Sakic a,

    E-print Network

    Technische Universiteit Delft

    Boron-layer silicon photodiodes for high-efficiency low-energy electron detection Agata Sakic´ a photodiodes Electron detection Low-energy electrons Boron deposition Ultrashallow junctions Responsivity for use as low-energy electron detectors have been fabricated using a pure-boron technology to form the p

  2. Determination of elements in polymers by laser ablation inductively coupled plasma atomic emission spectrometry: effect of the laser beam wavelength, energy and masking on the ablation threshold and efficiency

    NASA Astrophysics Data System (ADS)

    Hemmerlin, M.; Mermet, J. M.

    1996-05-01

    The application of laser ablation inductively coupled plasma atomic emission spectrometry (LA-ICP-AES) to the direct determination of solid inorganic additives in polymeric materials has been studied. The use of a Nd:YAG laser, operating at both infrared (IR) (1064 nm) and ultraviolet (UV) (355 and 266 nm) wavelengths, has been investigated for poly(vinylidene fluoride) (PVDF), poly(vinyl chloride) (PVC) and poly(ethylene) (PE) materials. In order to obtain reliable ablation conditions, emphasis was placed on the control of the experimental parameters and the understanding of the laser-surface interaction characteristics. It has been shown that, at low energies, a threshold process characterized by the swelling of the surface takes place, accounting for the rims surrounding the craters. This threshold was dependent not only on the energy, but also on the laser wavelength. In order to eliminate the formation of the swelling and to find the most reproducible conditions, it has been shown that the use of UV laser radiation and beam masking offer a better control of the laser ablation process, leading to a satisfactory relative standard deviation on both the estimated ablated mass (6.4%) and the emission signal obtained by ICP-AES (in the 2%-5% range). It has also been established that the optimum laser energy is in the frame of 6 mJ (10 J cm -2) to 10 mJ (14 J cm -2) at 266 nm. Erosion rate, linearity of the ablated mass against time for PVDF, PVC and PE, and a titanium calibration graph obtained for a PVC matrix are then briefly discussed and illustrate the technique's analytical potential.

  3. Clinical observation of atrial threshold monitoring algorithm: a single center experience

    PubMed Central

    She, Jianqing; Zhou, Jing; Hu, Zhan; Xia, Yulong

    2015-01-01

    Objective: To observe the atrial capture management in an atrial threshold monitoring algorithm. By calculating the enabling rate of the atrial threshold monitoring algorithm and comparing atrial thresholds measured automatically and manually, we evaluate its safety, reliability and applicability in clinical practice. Methods and results: Data were collected at implant, start of atrial threshold monitoring, visits scheduled 1 month, 2 months and 4 months thereafter, and upon notification of adverse events. Atrial threshold monitoring algorithm was enabled in 94 patients, while in 38 not, indicating an enabling rate of 71.2%. Causes of the unsuccessful attempts to enable automatic atrial threshold include tachycardia (2, 5.3%), and atrial safety margin not met (36, 94.7%). A total of 88 pairs of atrial thresholds measured automatically and manually were gained. The auto threshold was 0.528 ± 0.270 V, and the manual threshold was 0.580 ± 0.223 V. There is a strict correlation between the automatic measurements and those conducted manually by the physician with a P < 0.05. No significant differences were observed during the 1-month, 2-month and 4-month follow-up. Conclusion: Atrial threshold monitoring algorithm is safe, reliable and applicable over time. Atrial threshold monitoring tested atrial threshold was demonstrated to be clinically equivalent to the manual atrial threshold test. The addition of atrial threshold monitoring will benefit the patients by reducing energy cost and enhancing pacemaker safety. PMID:26131207

  4. Harmonic Analysis of Polynomial Threshold Functions

    Microsoft Academic Search

    Jehoshua Bruck

    1990-01-01

    The analysis of linear threshold Boolean functions has recently attracted the attention of those interested in circuit complexity as well as of those interested in neural networks. Here a generalization of linear threshold functions is defined, namely, polynomial threshold functions, and its relation to the class of linear threshold functions is investigated. A Boolean function is polynomial threshold if it

  5. Bayesian estimation of dose thresholds

    NASA Technical Reports Server (NTRS)

    Groer, P. G.; Carnes, B. A.

    2003-01-01

    An example is described of Bayesian estimation of radiation absorbed dose thresholds (subsequently simply referred to as dose thresholds) using a specific parametric model applied to a data set on mice exposed to 60Co gamma rays and fission neutrons. A Weibull based relative risk model with a dose threshold parameter was used to analyse, as an example, lung cancer mortality and determine the posterior density for the threshold dose after single exposures to 60Co gamma rays or fission neutrons from the JANUS reactor at Argonne National Laboratory. The data consisted of survival, censoring times and cause of death information for male B6CF1 unexposed and exposed mice. The 60Co gamma whole-body doses for the two exposed groups were 0.86 and 1.37 Gy. The neutron whole-body doses were 0.19 and 0.38 Gy. Marginal posterior densities for the dose thresholds for neutron and gamma radiation were calculated with numerical integration and found to have quite different shapes. The density of the threshold for 60Co is unimodal with a mode at about 0.50 Gy. The threshold density for fission neutrons declines monotonically from a maximum value at zero with increasing doses. The posterior densities for all other parameters were similar for the two radiation types.

  6. Methods of sequencing and detection using energy transfer labels with cyanine dyes as donor chromophores

    SciTech Connect

    Glazer, Alexander N. (Orinda, CA); Mathies, Richard A. (Moraga, CA); Hung, Su-Chun (Richmond, CA); Ju, Jingyue (Redwood City, CA)

    2000-01-01

    Cyanine dyes are used as the donor fluorophore in energy transfer labels in which light energy is absorbed by a donor fluorophore and transferred to an acceptor fluorophore which responds to the transfer by emitting fluorescent light for detection. The cyanine dyes impart an unusually high sensitivity to the labels thereby improving their usefulness in a wide variety of biochemical procedures, particularly nucleic acid sequencing, nucleic acid fragment sizing, and related procedures.

  7. Thresholds in conservation effectiveness under climate change

    NASA Astrophysics Data System (ADS)

    Hansen, A.; Phillips, L.

    2007-12-01

    We describe a new approach to conservation that derives from the effect of energy on ecosystem properties and then evaluate potential threshold responses of conservation effectiveness under climate change. Many tests of species energy theory provide evidence that species richness varies with measures of energy such as net primary productivity (NPP). Across continents, this relationship is most often unimodal, with species richness peaking in intermediate energy places and decreasing at higher NPP levels. NPP also influences ecosystem response to habitat fragmentation, recovery after disturbance, and trophic relationships. We have developed a topology for conservation whereby conservation priorities and management effectiveness differ among low, intermediate, and high energy ecosystems. We evaluated the projected change in NPP and conservation topology of ecoregions under future climate change scenarios. We found that projected NPP under climate change caused a subset of ecoregions to shift across the peak of the unimodal species energy curve, suggesting dramatic changes in conservation effectiveness are possible.

  8. An Alternative Energy Detection Using Sliding Window for Cognitive Radio System

    Microsoft Academic Search

    Young Min Kim; Guanbo Zheng; Sung Hwan Sohn; Jae Moung Kim

    2008-01-01

    Cognitive radio is one of the most effective techniques to improve the spectrum utilization efficiency. To implement the cognitive radio, spectrum sensing is considered as the key functionality because secondary users should identify the spectrum holes and utilize them efficiently without causing interference to primary users. In generally, there are three major spectrum sensing methods, including matched filter, energy detection

  9. FOREWORD: 3rd Symposium on Large TPCs for Low Energy Event Detection

    Microsoft Academic Search

    Igor G. Irastorza; Paul Colas; Phillippe Gorodetzky

    2007-01-01

    The Third International Symposium on large TPCs for low-energy rare-event detection was held at Carré des sciences, Poincaré auditorium, 25 rue de la Montagne Ste Geneviève in Paris on 11 12 December 2006. This prestigious location belonging to the Ministry of Research is hosted in the former Ecole Polytechnique. The meeting, held in Paris every two years, gathers a significant

  10. DEVELOPMENT OF A REAL-TIME FLUORESCENCE RESONANCE ENERGY TRANSFER PCR TO DETECT ARCOBACTER SPECIES

    Technology Transfer Automated Retrieval System (TEKTRAN)

    A real-time PCR targeting the gyrase A subunit gene outside the quinolone resistance-determining region has been developed to detect Arcobacter species. The species identification was made by probe hybridization and melting curve analysis, using Fluorescence Resonance Energy Transfer technology. D...

  11. Modelling energy flow in the vocal tract with applications to glottal closure and opening detection

    Microsoft Academic Search

    D. M. Brookes; H. P. Loke

    1999-01-01

    The pitch-synchronous analysis that is used in several areas of speech processing often requires robust detection of the instants of glottal closure and opening. In this paper we derive expressions for the flow of acoustic energy in the lossless-tube model of the vocal tract and show how linear predictive analysis may be used to estimate the waveform of acoustic input

  12. Array-based detection of persistent organic pollutants via cyclodextrin promoted energy transfer.

    PubMed

    Serio, Nicole; Moyano, Daniel F; Rotello, Vincent M; Levine, Mindy

    2015-07-25

    We report herein the selective array-based detection of 30 persistent organic pollutants via cyclodextrin-promoted energy transfer. The use of three fluorophores enabled the development of an array that classified 30 analytes with 100% accuracy and identified unknown analytes with 96% accuracy, as well as identifying 92% of analytes in urine. PMID:26096542

  13. Dynamics of negative bias thermal stress-induced threshold voltage shifts in indium zinc oxide transistors: impact of the crystalline structure on the activation energy barrier

    NASA Astrophysics Data System (ADS)

    Oh, Seungha; Yang, Bong Seob; Kim, Yoon Jang; Choi, Yu Jin; Kim, Un Ki; Han, Sang Jin; Lee, Hong Woo; Kim, Hyuk Jin; Kim, Sungmin; Kyeong Jeong, Jae; Kim, Hyeong Joon

    2014-04-01

    The kinetics of the negative bias thermal stress (NBTS)-induced Vth variations of indium zinc oxide (IZO) transistors with different crystallographic qualities were examined based on the stretched-exponential formalism. A poly-crystalline IZO device had a 0.64 eV lower activation barrier energy than an amorphous IZO device under NBTS conditions. This was attributed to the difference in the migration energy barrier between poly-crystalline and amorphous IZO films. For the recovery process, however, the activation energy barriers (˜0.75 eV) were independent of the crystal structure. A plausible microscopic mechanism to account for the experimental results is proposed.

  14. Threshold meson production and cosmic ray transport

    E-print Network

    John W. Norbury; Lawrence W. Townsend; Ryan B. Norman

    2006-12-11

    An interesting accident of nature is that the peak of the cosmic ray spectrum, for both protons and heavier nuclei, occurs near the pion production threshold. The Boltzmann transport equation contains a term which is the cosmic ray flux multiplied by the cross section. Therefore when considering pion and kaon production from proton-proton reactions, small cross sections at low energy can be as important as larger cross sections at higher energy. This is also true for subthreshold kaon production in nuclear collisions, but not for subthreshold pion production.

  15. Summing tree graphs at threshold

    E-print Network

    Lowell S. Brown

    1992-09-01

    The solution of the classical field equation generates the sum of all tree graphs. We show that the classical equation reduces to an easily solved ordinary differential equation for certain multiparticle threshold amplitudes and compute these amplitudes.

  16. s-wave threshold in electron attachment - Results in 2-C4F6 and CFCl3 at ultra-low electron energies

    NASA Technical Reports Server (NTRS)

    Chutjian, A.; Alajajian, S. H.; Ajello, J. M.; Orient, O. J.

    1984-01-01

    Electron attachment lineshapes and cross sections are reported for the processes 2-C4F6(-)/2-C4F6 and Cl(-)/CFCl3 at electron energies of 0-120 and 0-140 meV, and at resolutions of 6 and 7 meV (FWHM), respectively. As in previous measurements in CCl4 and SF6, the results show resolution-limited narrow structure in the cross section at electron energies below 15 meV. This structure arises from the divergence of the s-wave cross section in the limit of zero electron energy. Comparisons are given with swarm-measured results, and with collisional ionization (high-Rydberg attachment) data in this energy range.

  17. A database of local masking thresholds in natural images

    NASA Astrophysics Data System (ADS)

    Alam, Md Mushfiqul; Vilankar, Kedarnath P.; Chandler, Damon M.

    2013-03-01

    The ability of an image region to hide or mask a target signal continues to play a key role in the design of numerous image-processing and vision applications. However, one of the challenges in designing an effective model of masking for natural images is the lack of ground-truth data. To address this issue, this paper describes a psychophysical study designed to obtain local contrast detection thresholds (masking maps) for a database of natural images. Via a three-alternative forced-choice experiment, we measured the thresholds for detecting 3.7 cycles/deg vertically oriented log-Gabor targets placed within each 85×85-pixel patch (1.9 deg patch) of 15 natural images from the CSIQ image database [Larson and Chandler, JEI, 2010]. Thus, for each image, we obtained a masking map in which each entry in the map denotes the RMS contrast threshold for detecting the log-Gabor target at the corresponding spatial location in the image. Here, we describe the psychophysical procedures used to collect the thresholds, we provide analyses of the results, and we provide some outcomes of predicting the thresholds via basic low-level features, a computational masking model, and two modern imagequality assessment algorithms.

  18. Systematics of Low Threshold Modulation Searches in DMS II

    NASA Astrophysics Data System (ADS)

    Speller, D. H.

    The Cryogenic Dark Matter Search experiment (CDMS II) used underground-based germanium and silicon detectors to search for the scattering of Weakly Interacting Massive Particles (WIMPs), which are among the leading candidates for the dark matter component of the universe. Using the ionization and athermal phonons measured in particle interactions, CDMS II was able to achieve excellent discrimination between the nuclear recoils expected for WIMP interactions and radioactively produced electron recoils. With the rise of interest in the low energy interactions of light mass WIMPs, the SuperCDMS collaboration has undertaken a search for an annually modulating signal at low thresholds in the CDMS II data. Previous results detailed the analysis of data from eight germanium detectors over the course of six runs, to thresholds of 5 keVnr (nuclear recoil equivalent energy). We will discuss the impact of systematics at these low thresholds and their implications for thresholds down to 2.27 keVnr.

  19. Wavelet Image Denoising Using Localized Thresholding Operators

    Microsoft Academic Search

    Mohsen Ghazel; George H. Freeman; Edward R. Vrscay; Rabab K. Ward

    2005-01-01

    \\u000a In this paper, a localized wavelet thresholding strategy which adopts context-based thresholding operators is proposed. Traditional\\u000a wavelet thresholding methods, such as VisuShrink, LevelShrink and BayesShrink, apply the conventional hard and soft thresholding\\u000a operators and only differ in the selection of the threshold. The conventional soft and hard thresholding operators are point\\u000a operators in the sense that only the value of

  20. Real-Time Building Energy Modeling, fault Detection and Diagnostic for a DoD Building 

    E-print Network

    Dong, B.

    2013-01-01

    ME 4343 HVAC Design Real-Time Building Energy Modeling and Fault Detection and Diagnostics for a DoD Building Bing Dong1, Zheng O’Neill2 1 University of Texas, San Antonio, TX, USA 2 University of Alabama, AL, USA The work was done at the United...-12-18 CATEE 2013: Clean Air Through Energy Efficiency Conference, San Antonio, Texas Dec. 16-18 Introduction • HVAC systems consume >20% more energy than design intent – Equipment performance degradation, and interact with other systems.– Existing control...

  1. Threshold models in radiation carcinogenesis

    SciTech Connect

    Hoel, D.G.; Li, P. [Medical Univ. of South Carolina, Charleston, SC (United States). Dept. of Biometry and Epidemiology

    1998-09-01

    Cancer incidence and mortality data from the atomic bomb survivors cohort has been analyzed to allow for the possibility of a threshold dose response. The same dose-response models as used in the original papers were fit to the data. The estimated cancer incidence from the fitted models over-predicted the observed cancer incidence in the lowest exposure group. This is consistent with a threshold or nonlinear dose-response at low-doses. Thresholds were added to the dose-response models and the range of possible thresholds is shown for both solid tumor cancers as well as the different leukemia types. This analysis suggests that the A-bomb cancer incidence data agree more with a threshold or nonlinear dose-response model than a purely linear model although the linear model is statistically equivalent. This observation is not found with the mortality data. For both the incidence data and the mortality data the addition of a threshold term significantly improves the fit to the linear or linear-quadratic dose response for both total leukemias and also for the leukemia subtypes of ALL, AML, and CML.

  2. A detection system for very low-energy protons from {beta}-delayed proton decay

    SciTech Connect

    Spiridon, A.; Pollacco, E.; Trache, L.; Simmons, E.; McCleskey, M.; Roeder, B. T.; Tribble, R. E.; Pascovici, G.; Riallot, M.; Mols, J. P.; Kebbiri, M. [Cyclotron Institute, Texas A and M University, College Station, TX 77843-3366 (United States); CEA/IRFU Saclay, Gif-sur-Yvette (France); Cyclotron Institute, Texas A and M University, College Station, TX 77843-3366 (United States); Institut fuer Kernphysik der Universitaet zu Koeln, D-50937 Koeln (Germany); CEA/IRFU Saclay, Gif-sur-Yvette (France)

    2012-11-20

    We have recently developed a gas based detection system called AstroBox, motivated by nuclear astrophysics studies. The goal was to detect very low-energy protons from {beta}-delayed p-decay with reduced beta background and improved energy resolution. The detector was tested using the {beta}-delayed proton-emitter 23Al previously studied with a set-up based on thin double-sided Si strip detectors. The proton spectrum obtained with AstroBox showed no beta background down to {approx}80 keV. The low energy (206 keV, 267 keV) proton peaks were positively identified, well separated, and the resolution was improved.

  3. Dark energy with non-adiabatic sound speed: initial conditions and detectability

    E-print Network

    Guillermo Ballesteros; Julien Lesgourgues

    2010-10-27

    Assuming that the universe contains a dark energy fluid with a constant linear equation of state and a constant sound speed, we study the prospects of detecting dark energy perturbations using CMB data from Planck, cross-correlated with galaxy distribution maps from a survey like LSST. We update previous estimates by carrying a full exploration of the mock data likelihood for key fiducial models. We find that it will only be possible to exclude values of the sound speed very close to zero, while Planck data alone is not powerful enough for achieving any detection, even with lensing extraction. We also discuss the issue of initial conditions for dark energy perturbations in the radiation and matter epochs, generalizing the usual adiabatic conditions to include the sound speed effect. However, for most purposes, the existence of attractor solutions renders the perturbation evolution nearly independent of these initial conditions.

  4. Dark energy with non-adiabatic sound speed: initial conditions and detectability

    SciTech Connect

    Ballesteros, Guillermo [Museo Storico della Fisica e Centro Studi e Ricerche ''Enrico Fermi'', Piazza del Viminale 1, I-00184, Rome (Italy); Lesgourgues, Julien, E-mail: ballesteros@pd.infn.it, E-mail: julien.lesgourgues@cern.ch [CERN, Theory Division, CH-1211 Geneva 23 (Switzerland)

    2010-10-01

    Assuming that the universe contains a dark energy fluid with a constant linear equation of state and a constant sound speed, we study the prospects of detecting dark energy perturbations using CMB data from Planck, cross-correlated with galaxy distribution maps from a survey like LSST. We update previous estimates by carrying a full exploration of the mock data likelihood for key fiducial models. We find that it will only be possible to exclude values of the sound speed very close to zero, while Planck data alone is not powerful enough for achieving any detection, even with lensing extraction. We also discuss the issue of initial conditions for dark energy perturbations in the radiation and matter epochs, generalizing the usual adiabatic conditions to include the sound speed effect. However, for most purposes, the existence of attractor solutions renders the perturbation evolution nearly independent of these initial conditions.

  5. Possible Effects of Dark Energy on the Detection of Dark Matter Particles

    E-print Network

    Peihong Gu; Xiao-Jun Bi; Zhi-Hai Lin; Xinmin Zhang

    2005-03-14

    We study in this paper the possible influence of the dark energy on the detection of the dark matter particles. In models of dark energy described by a dynamical scalar field such as the Quintessence, its interaction with the dark matter will cause the dark matter particles such as the neutralino vary as a function of space and time. Given a specific model of the Quintessence and its interaction in this paper we calculate numerically the corrections to the neutralino masses and the induced spectrum of the neutrinos from the annihilation of the neutralinos pairs in the core of the Sun. This study gives rise to a possibility of probing for dark energy in the experiments of detecting the dark matter particles.

  6. Variability of argon laser-induced sensory and pain thresholds on human oral mucosa and skin.

    PubMed Central

    Svensson, P.; Bjerring, P.; Arendt-Nielsen, L.; Kaaber, S.

    1991-01-01

    The variability of laser-induced pain perception on human oral mucosa and hairy skin was investigated in order to establish a new method for evaluation of pain in the orofacial region. A high-energy argon laser was used for experimental pain stimulation, and sensory and pain thresholds were determined. The intra-individual coefficients of variation for oral thresholds were comparable to cutaneous thresholds. However, inter-individual variation was smaller for oral thresholds, which could be due to larger variation in cutaneous optical properties. The short-term and 24-hr changes in thresholds on both surfaces were less than 9%. The results indicate that habituation to laser thresholds may account for part of the intra-individual variation observed. However, the subjective ratings of the intensity of the laser stimuli were constant. Thus, oral thresholds may, like cutaneous thresholds, be used for assessment and quantification of analgesic efficacies and to investigate various pain conditions. PMID:1814248

  7. Electron-emission processes in highly charged Ar and Xe ions impinging on highly ordered pyrolytic graphite at energies just above the kinetic threshold

    NASA Astrophysics Data System (ADS)

    Bodewits, E.; Hoekstra, R.; Dobes, K.; Aumayr, F.

    2014-11-01

    At keV energies, many electronic processes contribute to the emission of secondary electrons in the interaction of highly charged ions on surfaces. To unravel contributions resulting from isolated hollow atoms in front of the surface or embedded in the electron gas of the target, heavy highly charged Ar and Xe ions are collided on highly ordered pyrolytic graphite (HOPG). A light target material as HOPG assures straight-line trajectories in the subsurface range. By a systematic change of incidence angle and energy of low-charged Ar and Xe ions, the kinetic electron emission component is determined. Separating out the kinetic energy contribution for the highly charged ions yields pure potential-energy-driven secondary-electron yields. From these yields it is concluded that in contrast to metallic targets, only a small fraction of the secondary electrons stem from above the surface. The lack of above-surface emission is likely due to the semimetallic electronic structure of HOPG. The subsurface emission is found to scale with the increase in binding energy of the inner-shell hole when incrementing the charge state of the projectile Ar or Xe ions.

  8. Preliminary results utilizing high-energy fission product ?-rays to detect fissionable material in cargo

    NASA Astrophysics Data System (ADS)

    Slaughter, D. R.; Accatino, M. R.; Bernstein, A.; Church, J. A.; Descalle, M. A.; Gosnell, T. B.; Hall, J. M.; Loshak, A.; Manatt, D. R.; Mauger, G. J.; Moore, T. L.; Norman, E. B.; Pohl, B. A.; Pruet, J. A.; Petersen, D. C.; Walling, R. S.; Weirup, D. L.; Prussin, S. G.; McDowell, M.

    2005-12-01

    A concept for detecting the presence of special nuclear material (235U or 239Pu) concealed in intermodal cargo containers is described. It is based on interrogation with a pulsed beam of 7 MeV neutrons that produce fission events and their ?-delayed neutron emission or ?-delayed high-energy ? radiation between beam pulses provide the detection signature. Fission product ?-delayed ?-rays above 3 MeV are nearly 10 times more abundant than ?-delayed neutrons and are distinct from natural radioactivity and from nearly all of the induced activity in a normal cargo. Detector backgrounds and potential interferences with the fission signature radiation have been identified and quantified.

  9. Radio surf in polar ice: A new method of ultrahigh energy neutrino detection

    SciTech Connect

    Ralston, John P. [Department of Physics and Astronomy, University of Kansas, Lawrence, Kansas 66045 (United States)

    2005-01-01

    We explore a new mechanism for detection of neutrino-induced showers via surface waves at radio frequencies. Air-dielectric surface waves exist on a plane boundaries that have attenuation lengths 2.82 that of the dielectric, and their amplitudes fall only by the inverse square root of propagation distance. Allowing for substantial coupling uncertainties, surface waves may provide a useful mechanism for neutrino detection in polar ice, promoting the development of neutrino telescopes in the energy regime above 10{sup 15} eV.

  10. A limit on the detectability of the energy scale of inflation

    E-print Network

    Lloyd Knox; Yong-Seon Song

    2002-02-15

    We show that the polarization of the cosmic microwave background can be used to detect gravity waves from inflation if the energy scale of inflation is above 3.2 times 10^15 GeV. These gravity waves generate polarization patterns with a curl, whereas (to first order in perturbation theory) density perturbations do not. The limiting ``noise'' arises from the second--order generation of curl from density perturbations, or rather residuals from its subtraction. We calculate optimal sky coverage and detectability limits as a function of detector sensitivity and observing time.

  11. Ultrasensitive detection of cellular protein interactions using bioluminescence resonance energy transfer quantum dot-based nanoprobes.

    PubMed

    Quiñones, Gabriel A; Miller, Steven C; Bhattacharyya, Sukanta; Sobek, Daniel; Stephan, Jean-Philippe

    2012-07-01

    Sensitive detection of protein interactions is a critical step toward understanding complex cellular processes. As an alternative to fluorescence-based detection, Renilla reniformis luciferase conjugated to quantum dots results in self-illuminating bioluminescence resonance energy transfer quantum dot (BRET-Qdot) nanoprobes that emit red to near-infrared bioluminescence light. Here, we report the development of an ultrasensitive technology based on BRET-Qdot conjugates modified with streptavidin ([BRET-Qdot]-SA) to detect cell-surface protein interactions. Transfected COS7 cells expressing human cell-surface proteins were interrogated with a human Fc tagged protein of interest. Specific protein interactions were detected using a biotinylated anti-human Fc region specific antibody followed by incubation with [BRET-Qdot]-SA. The luciferase substrate coelenterazine activated bioluminescence light emission was detected with an ultra-fast and -sensitive imager. Protein interactions barely detectable by the fluorescence-based approach were readily quantified using this technology. The results demonstrate the successful application and the flexibility of the BRET-Qdot-based imaging technology to the ultrasensitive investigation of cell-surface proteins and protein-protein interactions. PMID:22573556

  12. Near-threshold production of $W^\\pm$, $Z^0$ and $H^0$ at a fixed-target experiment at the future ultra-high-energy proton colliders

    E-print Network

    J. P. Lansberg; R. E. Mikkelsen; U. I Uggerhøj

    2015-07-06

    We outline the opportunities to study the production of the Standard Model bosons, $W^\\pm$, $Z^0$ and $H^0$ at "low" energies at fixed-target experiments based at possible future ultra-high-energy proton colliders, \\ie\\ the High-Energy LHC, the Super proton-proton Collider and the Future Circular Collider -- hadron-hadron. These can be indeed made in conjunction with the proposed future colliders designed to reach up to $\\sqrt{s}=100$ TeV by using bent crystals to extract part of the halo of the beam which would then impinge on a fixed target. Without disturbing the collider operation, this technique allows for the extraction of a substantial amount of particles in addition to serve for a beam-cleaning purpose. With this method, high-luminosity fixed-target studies at centre-of-mass energies above the $W^\\pm$, $Z^0$ and $H^0$ masses, $\\sqrt{s} \\simeq 170-300$ GeV, are possible. We also discuss the possibility offered by an internal gas target, which can also be used as luminosity monitor by studying the beam transverse shape.

  13. Near-threshold production of $W^\\pm$, $Z^0$ and $H^0$ at a fixed-target experiment at the future ultra-high-energy proton colliders

    E-print Network

    Lansberg, J P; Uggerhøj, U I

    2015-01-01

    We outline the opportunities to study the production of the Standard Model bosons, $W^\\pm$, $Z^0$ and $H^0$ at "low" energies at fixed-target experiments based at possible future ultra-high-energy proton colliders, \\ie\\ the High-Energy LHC, the Super proton-proton Collider and the Future Circular Collider -- hadron-hadron. These can be indeed made in conjunction with the proposed future colliders designed to reach up to $\\sqrt{s}=100$ TeV by using bent crystals to extract part of the halo of the beam which would then impinge on a fixed target. Without disturbing the collider operation, this technique allows for the extraction of a substantial amount of particles in addition to serve for a beam-cleaning purpose. With this method, high-luminosity fixed-target studies at centre-of-mass energies above the $W^\\pm$, $Z^0$ and $H^0$ masses, $\\sqrt{s} \\simeq 170-300$ GeV, are possible. We also discuss the possibility offered by an internal gas target, which can also be used as luminosity monitor by studying the beam ...

  14. Two-photon above-threshold ionization of hydrogen over the photon energy range from 15 eV to 50 keV

    SciTech Connect

    Florescu, Viorica; Budriga, Olimpia; Bachau, Henri [Department of Physics and Centre for Advanced Quantum Physics, University of Bucharest, MG-11, R-077125 Bucharest-Magurele (Romania); National Institute for Laser, Plasma and Radiation Physics, R-077125 Bucharest-Magurele (Romania); Centre des Lasers Intenses et Applications, Universite Bordeaux I-CNRS-CEA, F-33405 Talence Cedex (France)

    2011-09-15

    We investigate the absorption of two identical photons from the ground state of hydrogen-like atoms over an energy range that extends beyond that explored up to now. Our approach is based on a hybrid formula, valid in second-order perturbation theory, in which the A{sup 2} contribution from the nonrelativistic Hamiltonian is treated exactly, while the A{center_dot}P contribution is calculated in dipole approximation. We find that, at least up to 50 keV, the nonrelativistic dipole approximation, based only on the A{center_dot}P contribution, determines the values of the total cross section. Our numerical results, covering photon energies from 90 nm (13.7 eV) to 0.0248 nm (50 keV) are in very good agreement with most previous theoretical works. Differences with recent results are discussed.

  15. Shearlet-Based Adaptive Shrinkage Threshold for Image Denoising

    Microsoft Academic Search

    Xi Chen; Chengzhi Deng; Shengqian Wang

    2010-01-01

    An adaptive shrinkage threshold for image denoising in shearlet domain is presented. The shearlet transform not only provides the mean to detect orientations and to lead to sparse representations, but is moreover equipped with a rich mathematical structure similar to wavelets. Finally, a simulation is carried out to show the effectiveness of the new estimator. Experimental results show that the

  16. Image Thresholding Using Mean-Shift Based Particle Swarm Optimization

    Microsoft Academic Search

    Chien-cheng Lee; Yu-chun Chiang; Cheng-yuan Shih; Wen-sheng Hu

    2008-01-01

    In this paper, we propose a mean shift based particle swarm optimization (MS-PSO) algorithm to solve the image thresholding problem. PSO is an emerging evolutionary algorithm. However, the traditional PSO uses random number to move to the optimal position. The best position is based on random trials. Therefore, it often just detects the sub-optimal solutions due to its intrinsic stochastic

  17. Hybrid aptamer-antibody linked fluorescence resonance energy transfer based detection of trinitrotoluene.

    PubMed

    Sabherwal, Priyanka; Shorie, Munish; Pathania, Preeti; Chaudhary, Shilpa; Bhasin, K K; Bhalla, Vijayender; Suri, C Raman

    2014-08-01

    Combining synthetic macromolecules and biomolecular recognition units are promising in developing novel diagnostic and analysis techniques for detecting environmental and/or clinically important substances. Fluorescence resonance energy transfer (FRET) apta-immunosensor for explosive detection is reported using 2,4,6-trinitrotoluene (TNT) specific aptamer and antibodies tagged with respective FRET pair dyes in a sandwich immunoassay format. FITC-labeled aptamer was used as a binder molecule in the newly developed apta-immunoassay format where the recognition element was specific anti-TNT antibody labeled with rhodamine isothiocyanate. The newly developed sensing platform showed excellent sensitivity with a detection limit of the order of 0.4 nM presenting a promising candidate for routine screening of TNT in samples. PMID:25008849

  18. Determination of the Minimum Energy Required for Sonic-IR Detection

    NASA Astrophysics Data System (ADS)

    Lick, K. E.; Wong, C. H.; Chen, J. C.

    2007-03-01

    Sonic IR inspection is typically conducted using a commercial, off-the-shelf, ultrasonic welding gun driven by a matching, high-powered supply, regardless of the shape, size, mass or material under inspection. Often times, the power delivered to the sample is orders of magnitude higher than is required for detection of the defects present. Such `over-driving' of the samples may render sonic IR a destructive inspection method, which is obviously undesirable. In this study, the goal is to determine the minimum energy required for detecting cracks using sonic IR. This paper will discuss the experimental apparatus to simulate crack detection using sonic IR, which will then be used to calibrate the test setups instruments. With this task completed, conventional sonic IR experiments will then be conducted with controlled power delivery to the samples in order to achieve our goal. This presentation will discuss the approach to this experiment, its design, and some preliminary data.

  19. The perceptual threshold for overweight.

    PubMed

    Johnson, William G; Stewart, Regan; Pusser, Andrea T

    2012-08-01

    Normative, global overweight may play a prominent role in perpetuating the obesity epidemic via its contribution to weight-related norms that describe what is customary in a social environment. These weight-related norms include a perceptual standard determining where body weight shifts from normal to overweight. We introduce the construct of a perceptual threshold for overweight to identify this transition point. The perceptual threshold is measured on 0-100mm scales positioned below adult and child figures. This report presents three studies that evaluate the psychometric properties of this variable. Study 1explored its independence from BMI and body image in factor analyses with diverse samples (Ukrainian, Mexican and US Black, White, and Hispanic). Study 2 was a replication of this factor structure, and Study 3 investigated the reliability of the perceptual threshold using classical test (CT) and generalizability methods (GT). In Studies 1 and 2, two factors were identified (Perceptual Threshold for Overweight and Body Image/BMI) with almost identical factor structures in six analyses. In Study 3 the CT and GT procedures demonstrated adequate reliability. These results indicate that the psychometric properties of the perceptual threshold are sound, and support its use in exploring the social transmission of weight and evaluating obesity prevention and intervention programs. PMID:22664395

  20. High-Damage-Threshold Pinhole for Glass Fusion Laser Applications

    SciTech Connect

    Kumit, N.A.; Letzring, S.A.; Johnson, R.P.

    1998-06-07

    We are investigating methods to fabricate high-damage-threshold spatial-filter pinholes that might not be susceptible to plasma closure for relatively high energies and long pulses. These are based on the observation that grazing-incidence reflection from glass can withstand in excess of 5 kJ/cm{sup 2} (normal to the beam) without plasma formation. The high damage threshold results from both the cos q spreading of the energy across the surface and the reflection of a large fraction of the energy from the surface, thereby greatly reducing the field strength within the medium.

  1. Quantitative design and evaluation of enhancement\\/thresholding edge detectors

    Microsoft Academic Search

    I. E. Abdou; W. K. Pratt

    1979-01-01

    Quantitative design and performance evaluation techniques are developed for the enhancement\\/thresholding class of image edge detectors. The design techniques are based on statistical detection theory and deterministic pattern-recognition classification procedures. The performance evaluation methods developed include: a)deterministic measurement of the edge gradient amplitude; b)comparison of the probabilities of correct and false edge detection; and c) figure of merit computation. The

  2. Improved adaptive wavelet threshold for image denoising

    Microsoft Academic Search

    Wei Zhang; Fei Yu; Hong-mi Guo

    2009-01-01

    Adaptive wavelet threshold for Bayes shrink (Bayes threshold) is a simple and effective method for image denoising. Multiple wavelet representations have excellent performance in image denoising. In this paper, combining the multiple wavelet representations with the Bayes threshold and using their advantages in image denoising, proposes a new image denoising algorithm which called M-Bayes threshold. It is simple and effective.

  3. Gray Level Thresholding in Badly Illuminated Images

    Microsoft Academic Search

    J. R. Parker

    1991-01-01

    The thresholding method involves first locating objects in an image by using the intensity gradient, then noting the levels that correspond to the objects in various areas of the image, and finally using these levels as initial guesses at a threshold. This method is capable of thresholding images that have been produced in the context of variable illumination. The thresholding

  4. Soft threshold stochastic resonance Priscilla E. Greenwood

    E-print Network

    Mueller, Uschi

    Soft threshold stochastic resonance Priscilla E. Greenwood Arizona State University Ursula U. M¨uller Universit¨at Bremen Lawrence M. Ward University of British Columbia Abstract Soft thresholds are ubiquitous. Which soft threshold functions produce (threshold) stochastic resonance remains a question. The answer

  5. Magnetized neutron stars as gamma-ray bursters - Detection rates at high energies

    NASA Technical Reports Server (NTRS)

    Meszaros, P.; Bagoly, Z.; Riffert, H.

    1989-01-01

    Detailed calculations of the escape of high-energy gamma-rays from the dipolar magnetosphere of general relativistic neutron star models are used to model the detection rate of bursters at high photon energies between 0.3 and 10 MeV. This analysis shows the SMM detection rates to be compatible with a magnetized neutron star origin, with a distribution of magnetic field strengths extending at least up to about 4 x 10 to the 12th G, as expected if the (20-60) keV features reported from Konus and Ginga measurements are interpreted as cyclotron lines. Additional implications are discussed for the emission geometry and the neutron star radius.

  6. Magnetized neutron stars as gamma-ray bursters - Detection rates at high energies

    SciTech Connect

    Meszaros, P.; Bagoly, Z.; Riffert, H.

    1989-02-01

    Detailed calculations of the escape of high-energy gamma-rays from the dipolar magnetosphere of general relativistic neutron star models are used to model the detection rate of bursters at high photon energies between 0.3 and 10 MeV. This analysis shows the SMM detection rates to be compatible with a magnetized neutron star origin, with a distribution of magnetic field strengths extending at least up to about 4 x 10 to the 12th G, as expected if the (20-60) keV features reported from Konus and Ginga measurements are interpreted as cyclotron lines. Additional implications are discussed for the emission geometry and the neutron star radius. 17 refs.

  7. Addressing the Challenges of Anomaly Detection for Cyber Physical Energy Grid Systems

    SciTech Connect

    Ferragut, Erik M [ORNL; Laska, Jason A [ORNL; Melin, Alexander M [ORNL; Czejdo, Bogdan [ORNL

    2013-01-01

    The consolidation of cyber communications networks and physical control systems within the energy smart grid introduces a number of new risks. Unfortunately, these risks are largely unknown and poorly understood, yet include very high impact losses from attack and component failures. One important aspect of risk management is the detection of anomalies and changes. However, anomaly detection within cyber security remains a difficult, open problem, with special challenges in dealing with false alert rates and heterogeneous data. Furthermore, the integration of cyber and physical dynamics is often intractable. And, because of their broad scope, energy grid cyber-physical systems must be analyzed at multiple scales, from individual components, up to network level dynamics. We describe an improved approach to anomaly detection that combines three important aspects. First, system dynamics are modeled using a reduced order model for greater computational tractability. Second, a probabilistic and principled approach to anomaly detection is adopted that allows for regulation of false alerts and comparison of anomalies across heterogeneous data sources. Third, a hierarchy of aggregations are constructed to support interactive and automated analyses of anomalies at multiple scales.

  8. Improved visual background extractor using an adaptive distance threshold

    NASA Astrophysics Data System (ADS)

    Han, Guang; Wang, Jinkuan; Cai, Xi

    2014-11-01

    Camouflage is a challenging issue in moving object detection. Even the recent and advanced background subtraction technique, visual background extractor (ViBe), cannot effectively deal with it. To better handle camouflage according to the perception characteristics of the human visual system (HVS) in terms of minimum change of intensity under a certain background illumination, we propose an improved ViBe method using an adaptive distance threshold, named IViBe for short. Different from the original ViBe using a fixed distance threshold for background matching, our approach adaptively sets a distance threshold for each background sample based on its intensity. Through analyzing the performance of the HVS in discriminating intensity changes, we determine a reasonable ratio between the intensity of a background sample and its corresponding distance threshold. We also analyze the impacts of our adaptive threshold together with an update mechanism on detection results. Experimental results demonstrate that our method outperforms ViBe even when the foreground and background share similar intensities. Furthermore, in a scenario where foreground objects are motionless for several frames, our IViBe not only reduces the initial false negatives, but also suppresses the diffusion of misclassification caused by those false negatives serving as erroneous background seeds, and hence shows an improved performance compared to ViBe.

  9. Wavelet thresholding of multivalued images.

    PubMed

    Scheunders, Paul

    2004-04-01

    In this paper, a denoising technique for multivalued images exploiting interband correlations is proposed. A redundant wavelet transform is applied and denoising is applied by thresholding wavelet coefficients. Specific functions of the wavelet coefficients are defined that exploit interscale and/or interband correlation of the signal. Three functions are studied: the square of the wavelet coefficients, products of coefficients at adjacent scales, and products of coefficients from different bands. For these functions, the signal and noise probability density functions (pdf) become more separated. The high signal correlation between bands is exploited by summing these products over all bands, in this way separating noise and signal pdfs even more. The noise pdf of the proposed quantities is derived analytically and from this, a wavelet threshold is derived. The technique is demonstrated to outperform single band wavelet thresholding on multispectral remote sensing images and on multimodal MRI images. PMID:15376582

  10. Predicting percolation thresholds in networks

    NASA Astrophysics Data System (ADS)

    Radicchi, Filippo

    2015-01-01

    We consider different methods, which do not rely on numerical simulations of the percolation process, to approximate percolation thresholds in networks. We perform a systematic analysis on synthetic graphs and a collection of 109 real networks to quantify their effectiveness and reliability as prediction tools. Our study reveals that the inverse of the largest eigenvalue of the nonbacktracking matrix of the graph often provides a tight lower bound for true percolation threshold. However, in more than 40 % of the cases, this indicator is less predictive than the naive expectation value based solely on the moments of the degree distribution. We find that the performance of all indicators becomes worse as the value of the true percolation threshold grows. Thus, none of them represents a good proxy for the robustness of extremely fragile networks.

  11. Threshold concepts in dental education.

    PubMed

    Kinchin, I M; Cabot, L B; Kobus, M; Woolford, M

    2011-11-01

    The paper presents a conceptual framework to inform dental education. Drawing from a vast body of research into student learning, the simple model presented here has an explanatory value in describing what is currently observed to happen and a predictive value in guiding future teaching practices. We introduce to dental education the application of threshold concepts that have a transformative role in offering a new vision of the curriculum that helps to move away from the medieval transmission model of higher education towards a dual processing model that better reflects the way in which professionals operate within the discipline. Threshold concepts give a role for the student voice in offering a novice perspective which is paradoxically something that is out of reach of the subject expert. Finally, the application of threshold concepts highlights some of the weaknesses in the competency-based training model of clinical teaching. PMID:21985204

  12. Anomaly in the KS0?+ photoproduction cross section off the proton at the K* threshold

    NASA Astrophysics Data System (ADS)

    Ewald, R.; Bantes, B.; Bartholomy, O.; Bayadilov, D.; Beck, R.; Beloglazov, Y. A.; Brinkmann, K.-T.; Crede, V.; Dutz, H.; Elsner, D.; Fornet-Ponse, K.; Frommberger, F.; Funke, Ch.; Gridnev, A. B.; Gutz, E.; Hillert, W.; Hannappel, J.; Hoffmeister, P.; Jaegle, I.; Jahn, O.; Jude, T.; Junkersfeld, J.; Kalinowsky, H.; Kammer, S.; Kleber, V.; Klein, Frank; Klein, Friedrich; Klempt, E.; Krusche, B.; Lang, M.; Löhner, H.; Lopatin, I. V.; Menze, D.; Mertens, T.; Messchendorp, J. G.; Metag, V.; Nanova, M.; Novinski, D.; Novotny, R.; Ostrick, M.; Pant, L.; van Pee, H.; Roy, A.; Schadmand, S.; Schmidt, C.; Schmieden, H.; Schoch, B.; Shende, S.; Sokhoyan, V.; Süle, A.; Sumachev, V. V.; Szczepanek, T.; Thoma, U.; Trnka, D.; Varma, R.; Walther, D.; Wendel, Ch.; Cbelsa/Taps Collaboration

    2012-07-01

    The ?+p?K0+?+ photoproduction reaction is investigated in the energy region from threshold to E?=2250 MeV. The differential cross section exhibits increasing forward-peaking with energy, but only up to the K* threshold. Beyond, it suddenly returns to a flat distribution with the forward cross section dropping by a factor of four. In the total cross section a pronounced structure is observed between the K*? and K*? thresholds.

  13. Detection of phospholipid-carbon nanotube translocation using fluorescence energy transfer

    Microsoft Academic Search

    Sijie Lin; Gayatri Keskar; Yonnie Wu; Xi Wang; Andrew S. Mount; Stephen J. Klaine; Jessica M. Moore; Apparao M. Rao; Pu Chun Ke

    2006-01-01

    Single-walled carbon nanotubes (SWNTs) and lysophospholipids readily assemble into supramolecular complexes in aqueous solutions. Upon light excitation the fluorescence of rhodamine-labeled lysophospholipids was redshifted and quenched due to the optical absorption of the SWNTs. Utilizing fluorescence energy transfer, the authors detected the translocation and disassembly of SWNT complexes in MCF breast cancer cells. These lipid-coated SWNT complexes enable drugs to

  14. Mistiming Performance Analysis of the Energy Detection Based ToA Estimator for MB-OFDM

    Microsoft Academic Search

    Huilin Xu; Liuqing Yang; Y. T. Jade Morton; Mikel M. Miller

    2009-01-01

    In this letter, we apply energy detection based time- of-arrival (ToA) estimation to multi-band orthogonal frequency-division multiplexing signals. We analyze the mistiming performance of the ToA estimator in the Nakagami-m channel. Analysis shows that the slope of the probability of mistiming curve increases with the number of subbands and the Nakagami-m parameter. This is known in communications as diversity. Simulations

  15. Influence of radionuclide adsorption on detection efficiency and energy resolution for flow-cell radiation detectors

    Microsoft Academic Search

    T. A. DeVol; M. E. Keillor; L. W. Burggraf

    1996-01-01

    Flow-cell and batch test experiments were performed to determine the uranyl ion adsorption onto and\\/or complexation with CaF2:Eu scintillator as a function of pH. The flow-cell experiments were modeled with an energy dispersive Monte Carlo algorithm. At pH 2, the flow-cell and batch tests gave consistent results, detection efficiency ~60% and distribution coefficient (Kd ) ~0.3-0.7 mL\\/g, with the model.

  16. Radar for detection of ultra-high-energy neutrinos reacting in a rock salt dome

    NASA Astrophysics Data System (ADS)

    Chiba, Masami; Kamijo, Toshio; Yabuki, Fumiaki; Yasuda, Osamu; Akiyama, Hidetoshi; Chikashige, Yuichi; Kataoka, Hiromi; Kon, Tadashi; Shimizu, Yutaka; Taniuchi, Yasuyuki; Utsumi, Michiaki; Fujii, Masatoshi

    2012-01-01

    Detection of GZK (Greisen, Zatsepin and Kuzmin) neutrinos that have an energy larger than 1×1016 eV are expected to explore ultra-high-energy (UHE) interactions between UHE protons (>4×1019 eV) and cosmic-microwave background in the cosmological distances. A study of the radar method was carried out using a 2 MeV electron beam to irradiate rock salt powder filled in a 435 MHz waveguide. Reflection of radio wave from the irradiated rock-salt powder was observed inside the waveguide. The reflection mechanism was elucidated and the reflection power ratio was compared with a Fresnel equation.

  17. Real-Time Building Energy Modeling, fault Detection and Diagnostic for a DoD Building

    E-print Network

    Dong, B.

    2013-01-01

    ME 4343 HVAC Design Real-Time Building Energy Modeling and Fault Detection and Diagnostics for a DoD Building Bing Dong1, Zheng O’Neill2 1 University of Texas, San Antonio, TX, USA 2 University of Alabama, AL, USA The work was done at the United... distributed Direct Digital Control System (DDC) 4 7114 7113 ESL-KT-13-12-18 CATEE 2013: Clean Air Through Energy Efficiency Conference, San Antonio, Texas Dec. 16-18 Technology Approaches 5 Core Layer: BIM-based Database BIM to BEM Real-time Data Acquisition...

  18. Gridless retarding potential analyzer for use in very-low-energy charged particle detection

    NASA Technical Reports Server (NTRS)

    Shyn, T. W.; Sharp, W. E.; Hays, P. B.

    1976-01-01

    The theory of the hyperbolic retarding potential analyzer in the electrostatic mode is developed in detail and verified in the laboratory. A monoenergetic electron beam is used for the laboratory investigation. The analyzer (acronym HARP) has advantages over other conventional electrostatic analyzers; among them are less contact potential influence and high throughput because of the symmetry shape of the analyzer. The most useful application of the HARP is in detecting low-energy charged particles. A sample of low-energy particle data obtained in the earth's ionosphere is given.

  19. Calculations of atomic sputtering and displacement cross-sections in solid elements by electrons with energies from threshold to 1. 5 MV

    SciTech Connect

    Bradley, C.R.

    1988-12-01

    The kinetics of knock-on collisions of relativistic electrons with nuclei and details of the numerical evaluation of differential, recoil, and total Mott cross-sections are reviewed and discussed. The effects of electron beam induced displacement and sputtering, in the transmission electron microscope (TEM) environment, on microanalysis are analyzed with particular emphasis placed on the removal of material by knock-on sputtering. The mass loss predicted due to transmission knock-on sputtering is significant for many elements under conditions frequently encountered in microanalysis. Total Mott cross-sections are tabulated for all naturally occurring solid elements up to Z = 92 at displacement energies of one, two, four, and five times the sublimation energy and for accelerating voltages accessible in the transmission electron microscope. Fortran source code listings for the calculation of the differential Mott cross-section as a function of electron scattering angle (dMottCS), as a function of nuclear recoil angle (RECOIL), and the total Mott cross-section (TOTCS) are included. 48 refs., 21 figs., 12 tabs.

  20. Pulse variations of a conducted energy weapon (similar to the TASER X26 device): effects on muscle contraction and threshold for ventricular fibrillation*.

    PubMed

    Beason, Charles W; Jauchem, James R; Clark, C D; Parker, James E; Fines, David A

    2009-09-01

    Conducted energy weapons (such as the Advanced TASER X26 model produced by TASER International), incapacitate individuals by causing muscle contractions. To provide information relevant to development of future potential devices, a "Modifiable Electronic Stimulator" was used to evaluate the effects of changing various parameters of the stimulating pulse. Muscle contraction was affected by pulse power, net/gross charge, pulse duration, and pulse repetition frequency. The contraction force increased linearly as each of these factors was increased. Elimination of a precursor pulse from X26-like pulses did not have a significant effect on the normalized force measured. Muscle-contraction force increased as the spacing increased from 5 to 20 cm, with no further change in force above 20 cm of spacing. Therefore, it is suggested that any future developments of new conducted energy weapons should include placement of electrodes a minimum of 20 cm apart so that efficiency of the system is not degraded. In the current study, the 50% probability of fibrillation level of X26-like pulses ranged from 4 to 5 times higher than the X26 itself. Relatively large variations about the X26 operating level were found not to result in fibrillation or asystole. Therefore, it should be possible to design and build an X26-type device that operates efficiently at levels higher than the X26. PMID:19737245

  1. Absence of a {open_quote}{open_quote}Threshold Effect{close_quote}{close_quote} in the Energy Loss of Slow Protons Traversing Large-Band-Gap Insulators

    SciTech Connect

    Eder, K.; Semrad, D.; Bauer, P. [Institut fuer Experimentalphysik, Johannes-Kepler Universitaet Linz, A-4040 Linz (Austria)] [Institut fuer Experimentalphysik, Johannes-Kepler Universitaet Linz, A-4040 Linz (Austria); Golser, R. [Institut fuer Radiumforschung und Kernphysik, Universitaet Wien, A-1090 Wien (Austria)] [Institut fuer Radiumforschung und Kernphysik, Universitaet Wien, A-1090 Wien (Austria); Maier-Komor, P. [Target Laboratory, Technical University Munich, D-85748 Garching (Germany)] [Target Laboratory, Technical University Munich, D-85748 Garching (Germany); Aumayr, F. [Institut fuer Allgemeine Physik, Technische Universitaet Wien, A-1040 Wien (Austria)] [Institut fuer Allgemeine Physik, Technische Universitaet Wien, A-1040 Wien (Austria); Penalba, M. [Departamento de Fisica Aplicada I, E.T.S.I.I. y T., Universidad del Pais Vasco, Bilbao (Spain)] [Departamento de Fisica Aplicada I, E.T.S.I.I. y T., Universidad del Pais Vasco, Bilbao (Spain); Arnau, A.; Ugalde, J.M.; Echenique, P.M. [Departamento de Fisica de Materiales, Universidad del Pais Vasco, Apartado 1072, San Sebastian 20080 (Spain)] [Departamento de Fisica de Materiales, Universidad del Pais Vasco, Apartado 1072, San Sebastian 20080 (Spain)

    1997-11-01

    The electronic stopping cross section {var_epsilon} of slow hydrogen projectiles in large-band-gap insulators has been measured at energies of a few keV. Even at velocities as low as v{sub 0}/3 (v{sub 0}=c/137) , we find no influence of the band gap on the velocity dependence of {var_epsilon} , contrary to the case of gaseous targets with similar minimum excitation energy. The magnitude of {var_epsilon} and its essentially linear velocity dependence allow us to arrive at the following conclusion: Electron promotion processes contribute substantially to stopping due to formation of molecular orbitals. This points towards the existence of a bound electron state at a proton that moves slowly in an insulator. A simple model based on the calculation of molecular orbital correlation diagrams for the H/LiF collision system supports the idea of local reduction of the band gap of an insulating target. {copyright} {ital 1997} {ital The American Physical Society}

  2. Analysis of Pion Production Near Threshold for Carbon and Helium

    E-print Network

    Saskatchewan, University of

    Analysis of Pion Production Near Threshold for Carbon and Helium Michael Barnett Subatomic Physics- der, energy dependent correction factor for pion photoproduction from nuclei, specifically helium and carbon. This was done by examining the pion production cross section at energies within about 25 Me

  3. Search for E1 strength in 62,64Fe around the threshold

    NASA Astrophysics Data System (ADS)

    Wieland, O.; Bracco, A.; Camera, F.; affil="1, R.; pre="for ">the PRESPEC,

    2015-02-01

    The structure and nature of the pygmy dipole resonance (PDR) states below and above the neutron threshold is a recent open problem, particularly in exotic, neutron rich nuclei. Present experimental observations give only limited information on this subject. New experiments using different methods are needed. A recent measurement at the GSI laboratories on 62,64Fe with the PRESPEC (2014) setup, following a past experiment with the RISING (2005) setup on 68Ni, will contribute to solve the open questions. The setup located at GSI consists of the segmented HPGe detector array AGATA, scintillators (HECTOR), an Energy Loss / Total Energy time of flight measuring detector system called LYCCA and the fragment separator (FRS) apparatus. The experiment is based on relativistic Coulomb excitation together with the detection of the incoming and outgoing particles event by event. The detection of the produced y-rays in the reactions, provides insight into the problem of the electric dipole response and E1 strength distribution around particle separation threshold.

  4. Quark mass thresholds in QCD thermodynamics

    SciTech Connect

    Laine, Mikko; Schroeder, York [Faculty of Physics, University of Bielefeld, D-33501 Bielefeld (Germany)

    2006-04-15

    We discuss radiative corrections to how quark mass thresholds are crossed, as a function of the temperature, in basic thermodynamic observables such as the pressure, the energy and entropy densities, and the heat capacity of high temperature QCD. The indication from leading order that the charm quark plays a visible role at surprisingly low temperatures, is confirmed. We also sketch a way to obtain phenomenological estimates relevant for generic expansion rate computations at temperatures between the QCD and electroweak scales, pointing out where improvements over the current knowledge are particularly welcome.

  5. Technology Thresholds for Microgravity: Status and Prospects

    NASA Technical Reports Server (NTRS)

    Noever, D. A.

    1996-01-01

    The technological and economic thresholds for microgravity space research are estimated in materials science and biotechnology. In the 1990s, the improvement of materials processing has been identified as a national scientific priority, particularly for stimulating entrepreneurship. The substantial US investment at stake in these critical technologies includes six broad categories: aerospace, transportation, health care, information, energy, and the environment. Microgravity space research addresses key technologies in each area. The viability of selected space-related industries is critically evaluated and a market share philosophy is developed, namely that incremental improvements in a large markets efficiency is a tangible reward from space-based research.

  6. Handling of BLM abort thresholds in the LHC

    E-print Network

    Nebot Del Busto, E; Holzer, EB; Zamantzas, C; Kruk, G; Nordt, A; Sapinski, M; Nemcic, M; Orecka, A; Jackson, S; Roderick, C; Skaugen, A

    2011-01-01

    The Beam Loss Monitoring system (BLM) for the LHC consists of about 3600 Ionization Chambers (IC) located around the ring. Its main purpose is to request a beam abort when the measured losses exceed a certain threshold. The BLM detectors integrate the measured signals in 12 different time intervals (running from 40us to 83.8s) enabling for a different set of abort thresholds depending on the duration of the beam loss. Furthermore, 32 energy levels running from 450GeV to 7TeV account for the fact that the energy density of a particle shower increases with the energy of the primary particle, i.e. the beam energy. Thus, a set of ! 3600 × 12 × 32 = 1.3 · 106 thresholds must be handled. These thresholds are highly critical for the safety of the machine and depend to a large part on human judgment, which cannot be replaced by automatic test procedures. The BLM team has defined well established procedures to compute, set and check new BLM thresholds, in order to avoid and/or find non-conformities due to manipulat...

  7. Factors Affecting Perceptual Thresholds in Epiretinal Prostheses

    PubMed Central

    de Balthasar, Chloé; Patel, Sweta; Roy, Arup; Freda, Ricardo; Greenwald, Scott; Horsager, Alan; Mahadevappa, Manjunatha; Yanai, Douglas; McMahon, Matthew J.; Humayun, Mark S.; Greenberg, Robert J.; Weiland, James D.; Fine, Ione

    2008-01-01

    Purpose The goal was to evaluate how perceptual thresholds are related to electrode impedance, electrode size, the distance of electrodes from the retinal surface, and retinal thickness in six subjects blind as a result of retinitis pigmentosa, who received epiretinal prostheses implanted monocularly as part of a U.S. Food and Drug Administration (FDA)–approved clinical trial. Methods The implant consisted of an extraocular unit containing electronics for wireless data, power recovery, and generation of stimulus current, and an intraocular unit containing 16 platinum stimulating electrodes (260- or 520-?m diameter) arranged in a 4 × 4 pattern. The electrode array was held onto the retina by a small tack. Stimulation was controlled by a computer-based external system that allowed independent control over each electrode. Perceptual thresholds (the current necessary to see a percept on 79% of trials) and impedance were measured for each electrode on a biweekly basis. The distance of electrodes from the retinal surface and retinal thickness were measured by optical coherence tomography on a less regular basis. Results Stimulation thresholds for detecting phosphenes correlated with the distance of the electrodes from the retinal surface, but not with electrode size, electrode impedance, or retinal thickness. Conclusions Maintaining close proximity between the electrode array and the retinal surface is critical in developing a successful retinal implant. With the development of chronic electrode arrays that are stable and flush on the retinal surface, it is likely that the influence of other factors such as electrode size, retinal degeneration, and subject age will become more apparent. PMID:18515576

  8. Förster resonance-energy-transfer detection of 2,4,6-trinitrophenol using copper nanoclusters.

    PubMed

    Deng, Xiang; Huang, Xiaomei; Wu, Di

    2015-06-01

    Nitroaromatic compounds, for example trinitrotoluene and 2,4,6-trinitrophenol (TNP), are well-known primary constituents of many unexploded landmines worldwide. These compounds are recognized as environmental contaminants and as toxic to living organisms. Therefore, Förster resonance energy transfer (FRET) for TNP detection was developed on the basis of spectral overlap between the fluorescence spectrum of copper nanoclusters (CuNCs) and absorption spectrum of TNP (the calculated Förster distance R 0 of the donor CuNCs and the acceptor TNP is 2.8 nm). Water-soluble fluorescent CuNCs capped with bovine serum albumin have fluorescence emission from 350 nm to 500 nm with maximum fluorescence emission at 400 nm, which overlaps with the absorption spectra of TNP from 350 nm to 450 nm. Inspired by FRET structures, an unprecedented energy-donor-and-acceptor pair of fluorescent CuNCs and TNP is developed in this work. Fluorescence of CuNCs is quenched in the presence of TNP as a result of FRET from fluorescent CuNCs to TNP. Therefore a fluorescence quenching method for the determination of TNP is developed. It achieves TNP detection from 0.8 ?mol L(-1) to 100 ?mol L(-1), with response within 1 min and with good selectivity compared with that for other nitroaromatic compounds, including 2,4-dinitrotoluene, p-nitrotoluene, and nitrobenzene, and phenol. Graphical Abstract Förster resonance-energy-transfer detection of 2,4,6-trinitrophenol using copper nanoclusters was first developed. It achieves TNP detection from 0.8 mmol L(-1) to 100 mmol L(-1) within 1 min with good selectivity compared with other nitroaromatic compounds. PMID:25893800

  9. Olfactory dysfunction affects thresholds to trigeminal chemosensory sensations.

    PubMed

    Frasnelli, J; Schuster, B; Hummel, T

    2010-01-14

    Next to olfaction and gustation, the trigeminal system represents a third chemosensory system. These senses are interconnected; a loss of olfactory function also leads to a reduced sensitivity in the trigeminal chemosensory system. However, most studies so far focused on comparing trigeminal sensitivity to suprathreshold stimuli; much less data is available with regard to trigeminal sensitivity in the perithreshold range. Therefore we assessed detection thresholds for CO(2), a relatively pure trigeminal stimulus in controls and in patients with olfactory dysfunction (OD). We could show that OD patients exhibit higher detection thresholds than controls. In addition, we were able to explore the effects of different etiologies of smell loss on trigeminal detection thresholds. We could show that in younger subjects, patients suffering from olfactory loss due to head trauma are more severely impaired with regard to their trigeminal sensitivity than patients with isolated congenital anosmia. In older patients, we could not observe any differences between different etiologies, probably due to the well known age-related decrease of trigeminal sensitivity. Furthermore we could show that a betterment of the OD was accompanied by decreased thresholds. This was most evident in patients with postviral OD. In conclusion, factors such as age, olfactory status and etiology of olfactory disorder can affect responsiveness to perithreshold trigeminal chemosensory stimuli. PMID:19900505

  10. WAVELET THRESHOLDING OF MULTISPECTRAL IMAGES

    Microsoft Academic Search

    P. Scheunders

    In this paper a denoising technique for multispectral images is proposed. A redundant wavelet transform is applied and denois- ing is applied by thresholding wavelet coefficients. A distinction between signal and noise is made based on the sum over the bands of the squared detail coefficients. Since real edge infor- mation between different bands is correlated, this quantity opti- mally

  11. Wavelet thresholding of multivalued images

    Microsoft Academic Search

    Paul Scheunders

    2004-01-01

    In this paper a denoising technique for multivalued im- ages exploiting interband correlations is proposed. A redun- dant wavelet transform is applied and denoising is applied by thresholding wavelet coecien ts. Specic functions of the wavelet coecien ts are dened that exploit interscale and\\/or interband correlation of the signal. Three functions are studied: the square of the wavelet coecien ts,

  12. Instability threshold of gaseous detonations

    Microsoft Academic Search

    EMI D AOU; PAUL C LAVIN

    pments in nonlinear analyses for describing the cellular structure of weakly unstable detonation fronts, particular attention is paid to the neighbourhood of the instability threshold. A first objective is to check the validity domain of the analytical results and to investigate to what extent they are useful when approaching the self-sustained regime (Chapman-Jouguet conditions). A second objective is to study

  13. Fractal Superconductivity near Localization Threshold

    E-print Network

    Fominov, Yakov

    Fractal Superconductivity near Localization Threshold Mikhail Feigel'man Landau Institute, Moscow-electron states are extended but fractal and populate small fraction of the whole volume How BCS theory should be modified to account for eigenstates fractality ? #12;Mean-Field Eq. for Tc #12;#12;3D Anderson model: = 0

  14. Estimating Conservation Thresholds on Rangelands

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The Conservation Effects Assessment Project (CEAP) is a multi-agency effort designed to quantify the environmental and economic impacts of land conservation practices. One of USDA’s goals is to identify Conservation Thresholds, the point at which accelerated erosion occurs, and to examine the usefu...

  15. Threshold Criteria for Undervoltag Breakdown

    Microsoft Academic Search

    J. E. Cooley; E. Y. Choueiri

    2005-01-01

    Summary form only given. Undervoltage breakdown, the process by which a pulse of electrons induces a discharge gap to break down when it is near but has not achieved its self-breakdown conditions, is discussed. Specifically, threshold criteria that determine the number of electrons required to induce breakdown both to glow and arc discharges are presented. Numerical and theoretical predictions of

  16. Combining protein complementation assays with resonance energy transfer to detect multipartner protein complexes in living cells.

    PubMed

    Rebois, R Victor; Robitaille, Mélanie; Pétrin, Darlaine; Zylbergold, Peter; Trieu, Phan; Hébert, Terence E

    2008-07-01

    A variety of fluorescent proteins with different spectral properties have been created by mutating green fluorescent protein. When these proteins are split in two, neither fragment is fluorescent per se, nor can a fluorescent protein be reconstituted by co-expressing the complementary N- and C-terminal fragments. However, when these fragments are genetically fused to proteins that associate with each other in cellulo, the N- and C-terminal fragments of the fluorescent protein are brought together and can reconstitute a fluorescent protein. A similar protein complementation assay (PCA) can be performed with two complementary fragments of various luciferase isoforms. This makes these assays useful tools for detecting the association of two proteins in living cells. Bioluminescence resonance energy transfer (BRET) or fluorescence resonance energy transfer (FRET) occurs when energy from, respectively, a luminescent or fluorescent donor protein is non-radiatively transferred to a fluorescent acceptor protein. This transfer of energy can only occur if the proteins are within 100A of each other. Thus, BRET and FRET are also useful tools for detecting the association of two proteins in living cells. By combining different protein fragment complementation assays (PCA) with BRET or FRET it is possible to demonstrate that three or more proteins are simultaneous parts of the same protein complex in living cells. As an example of the utility of this approach, we show that as many as four different proteins are simultaneously associated as part of a G protein-coupled receptor signalling complex. PMID:18586102

  17. An energy-efficient cluster-based vehicle detection on road network using intention numeration method.

    PubMed

    Devasenapathy, Deepa; Kannan, Kathiravan

    2015-01-01

    The traffic in the road network is progressively increasing at a greater extent. Good knowledge of network traffic can minimize congestions using information pertaining to road network obtained with the aid of communal callers, pavement detectors, and so on. Using these methods, low featured information is generated with respect to the user in the road network. Although the existing schemes obtain urban traffic information, they fail to calculate the energy drain rate of nodes and to locate equilibrium between the overhead and quality of the routing protocol that renders a great challenge. Thus, an energy-efficient cluster-based vehicle detection in road network using the intention numeration method (CVDRN-IN) is developed. Initially, sensor nodes that detect a vehicle are grouped into separate clusters. Further, we approximate the strength of the node drain rate for a cluster using polynomial regression function. In addition, the total node energy is estimated by taking the integral over the area. Finally, enhanced data aggregation is performed to reduce the amount of data transmission using digital signature tree. The experimental performance is evaluated with Dodgers loop sensor data set from UCI repository and the performance evaluation outperforms existing work on energy consumption, clustering efficiency, and node drain rate. PMID:25793221

  18. Near-threshold production of the meson via the quasifree pnpn reaction

    Microsoft Academic Search

    P. Moskal; E. Czerwinski; M. Janusz; R. Czyzykiewicz; D. Gil; L. Jarczyk; B. Kamys; P. Klaja; J. Majewski; C. Piskor-Ignatowicz; J. Przerwa; B. Rejdych; M. Silarski; J. Smyrski; M. Zielinski; J. Zdebik; H.-H. Adam; A. Khoukaz; A. Taeschner; S. D. Bass

    2009-01-01

    Total cross sections for the quasifree pnpn reaction in the range from the kinematical threshold up to 20 MeV excess energy have been determined. At threshold they exceed corresponding cross sections for the pppp reaction by a factor of about 3 in contrast to the factor of 6 established for higher excess energies. To large extent, the observed decrease of

  19. Near-threshold production of the ? meson via the quasifree pn?pn? reaction

    Microsoft Academic Search

    P. Moskal; R. Czyzykiewicz; H.-H. Adam; S. D. Bass; A. Budzanowski; E. Czerwinski; D. Gil; D. Grzonka; M. Janusz; L. Jarczyk; T. Johansson; B. Kamys; A. Khoukaz; K. Kilian; P. Klaja; J. Majewski; W. Oelert; C. Piskor-Ignatowicz; J. Przerwa; B. Rejdych; J. Ritman; T. Rozek; T. Sefzick; M. Siemaszko; M. Silarski; J. Smyrski; A. Taschner; M. Wolke; P. Wustner; M. J. Zielinski; W. Zipper; J. Zdebik

    2009-01-01

    Total cross sections for the quasi-free pn ! pnreaction in the range from the kine- matical threshold up to 20 MeV excess energy have been determined. At threshold they exceed corresponding cross sections for the pp ! ppreaction by a factor of about three in contrast to the factor of six established for higher excess energies. To large extent, the

  20. Study of interstrip gap effects and efficiency for full energy detection of Double Sided Silicon Strip Detectors

    NASA Astrophysics Data System (ADS)

    Torresi, D.; Forneris, J.; Grassi, L.; Acosta, L.; Di Pietro, A.; Figuera, P.; Grilj, L.; Jaksi?, M.; Lattuada, M.; Mijatovi?, T.; Milin, M.; Prepolec, L.; Skukan, N.; Soi?, N.; Stanko, D.; Toki?, V.; Uroi?, M.; Zadro, M.

    2015-04-01

    In this work is reported a study on the response of double sided silicon strip detectors. In order to investigate the effect of the electrode segmentation on the detector response, two experiments were performed aimed to measure the efficiency for full energy detection. Results show that the efficiency for full energy detection, that is directly related to effective width of the inter-strip region, varies with both detected ion energy and bias voltage. The experimental results are qualitatively reproduced by a simplified model based on the Shockley-Ramo-Gunn framework.

  1. Superlinear threshold detectors in quantum cryptography

    SciTech Connect

    Lydersen, Lars; Maroey, Oystein; Skaar, Johannes; Makarov, Vadim [Department of Electronics and Telecommunications, Norwegian University of Science and Technology, NO-7491 Trondheim (Norway); University Graduate Center, NO-2027 Kjeller (Norway); Jain, Nitin; Wittmann, Christoffer; Marquardt, Christoph; Leuchs, Gerd [Max Planck Institute for the Science of Light, Guenther-Scharowsky-Strasse 1/Bau 24, DE-91058 Erlangen (Germany); Institut fuer Optik, Information und Photonik, University of Erlangen-Nuremberg, Staudtstrasse 7/B2, DE-91058 Erlangen (Germany)

    2011-09-15

    We introduce the concept of a superlinear threshold detector, a detector that has a higher probability to detect multiple photons if it receives them simultaneously rather than at separate times. Highly superlinear threshold detectors in quantum key distribution systems allow eavesdropping the full secret key without being revealed. Here, we generalize the detector control attack, and analyze how it performs against quantum key distribution systems with moderately superlinear detectors. We quantify the superlinearity in superconducting single-photon detectors based on earlier published data, and gated avalanche photodiode detectors based on our own measurements. The analysis shows that quantum key distribution systems using detector(s) of either type can be vulnerable to eavesdropping. The avalanche photodiode detector becomes superlinear toward the end of the gate. For systems expecting substantial loss, or for systems not monitoring loss, this would allow eavesdropping using trigger pulses containing less than 120 photons per pulse. Such an attack would be virtually impossible to catch with an optical power meter at the receiver entrance.

  2. Role of energy partitioning on electron-hole recombination, trapping, and detection in silicon detectors

    NASA Astrophysics Data System (ADS)

    Zhang, Yanwen; Weber, William J.

    2010-08-01

    The dynamics of electron-hole pair creation and transport in a semiconductor control the fundamental signal response for radiation detection. Extensive studies on silicon detectors have led to contradictory interpretations on the origins of the pulse height defect (PHD) and nonlinear response. In this study, recombination and trapping behaviors of a controlled number of electron-hole pairs produced within different volumes along the ion path are investigated, and the pulse height generated is analyzed in terms of energy partitioning. The results clearly demonstrate that a high recombination rate is not observed for heavy ions; moreover, significant trapping associated with the atomic defects produced by individual ions is responsible for the nonlinear response at low energies and PHD at high energies.

  3. Cherenkov light detection as a velocity selector for uranium fission products at intermediate energies

    NASA Astrophysics Data System (ADS)

    Yamaguchi, T.; Enomoto, A.; Kouno, J.; Yamaki, S.; Matsunaga, S.; Suzaki, F.; Suzuki, T.; Abe, Y.; Nagae, D.; Okada, S.; Ozawa, A.; Saito, Y.; Sawahata, K.; Kitagawa, A.; Sato, S.

    2014-12-01

    The in-flight particle separation capability of intermediate-energy radioactive ion (RI) beams produced at a fragment separator can be improved with the Cherenkov light detection technique. The cone angle of Cherenkov light emission varies as a function of beam velocity. This can be exploited as a velocity selector for secondary beams. Using heavy ion beams available at the HIMAC synchrotron facility, the Cherenkov light angular distribution was measured for several thin radiators with high refractive indices (n = 1.9 ~ 2.1). A velocity resolution of ~10-3 was achieved for a 56Fe beam with an energy of 500 MeV/nucleon. Combined with the conventional rigidity selection technique coupled with energy-loss analysis, the present method will enable the efficient selection of an exotic species from huge amounts of various nuclides, such as uranium fission products at the BigRIPS fragment separator located at the RI Beam Factory.

  4. The carbon-based structures synthesized through nuclear reactions in helium at 1.1?kbar pressure under irradiation with braking ?-rays of 10?MeV threshold energy

    NASA Astrophysics Data System (ADS)

    Didyk, A. Yu.; Wisniewski, R.; Wilczynska-Kitowska, T.

    2015-01-01

    A helium high-pressure chamber (HeHPC), made from beryllium bronze, filled with gaseous helium at an initial pressure of about 1.1 kbar was irradiated by braking ?-rays of 10 MeV threshold energy during 1.0×105 \\text{s} at an electron beam current 22\\text-24 ? \\text{A} . Before opening of the chamber, the residual pressure inside was equal to 430 bar. Synthesized foils of black colour and other multiple objects were found inside the HeHPC at the inner surfaces of the reaction chamber made of high-purity copper, at the entrance window for ?-rays of beryllium bronze, and at the copper collector of nuclear and chemical reaction products. The element analysis using scanning electron microscopy (SEM) and microprobe roentgen analysis (MPRA) allowed us to establish that the foils were predominantly made of carbon and smaller quantities of other elements from carbon to iron. The developed approach agrees well with a series of studies carried out by the authors where dense hydrogen and deuterium gases are acted on by ?-rays in the presence or absence of metals in the reaction chamber.

  5. Multiscale Energy and Eigenspace Approach to Detection and Localization of Myocardial Infarction.

    PubMed

    Sharma, L N; Tripathy, R K; Dandapat, S

    2015-07-01

    In this paper, a novel technique on a multiscale energy and eigenspace (MEES) approach is proposed for the detection and localization of myocardial infarction (MI) from multilead electrocardiogram (ECG). Wavelet decomposition of multilead ECG signals grossly segments the clinical components at different subbands. In MI, pathological characteristics such as hypercute T-wave, inversion of T-wave, changes in ST elevation, or pathological Q-wave are seen in ECG signals. This pathological information alters the covariance structures of multiscale multivariate matrices at different scales and the corresponding eigenvalues. The clinically relevant components can be captured by eigenvalues. In this study, multiscale wavelet energies and eigenvalues of multiscale covariance matrices are used as diagnostic features. Support vector machines (SVMs) with both linear and radial basis function (RBF) kernel and K-nearest neighbor are used as classifiers. Datasets, which include healthy control, and various types of MI, such as anterior, anteriolateral, anterioseptal, inferior, inferiolateral, and inferioposterio-lateral, from the PTB diagnostic ECG database are used for evaluation. The results show that the proposed technique can successfully detect the MI pathologies. The MEES approach also helps localize different types of MIs. For MI detection, the accuracy, the sensitivity, and the specificity values are 96%, 93%, and 99% respectively. The localization accuracy is 99.58%, using a multiclass SVM classifier with RBF kernel. PMID:26087076

  6. Nicking enzyme-assisted biosensor for Salmonella enteritidis detection based on fluorescence resonance energy transfer.

    PubMed

    Song, Yang; Li, Wenkai; Duan, Yingfen; Li, Zhongjie; Deng, Le

    2014-05-15

    Salmonella enteritidis (S. enteritidis) outbreaks continue to occur, and have increased public awareness of this pathogen. Nicking endonuclease Nb.BbvC I is widely used for the detection of biomolecules and displays activity for specific double-stranded DNA (dsDNA). In this study, we developed a biosensor to detect S. enteritidis based on fluorescence resonance energy transfer (FRET) using nicking enzyme and carbon nanoparticles (CNPs). Because of the quenching effect of black hole quencher 1 (BHQ 1), the CNPs do not fluoresce in the reaction system. When the target bacteria are added, the nicking enzyme recognizes and cleaves the dsDNA fabricated by the interaction between probe and target. As a result, the CNPs dissociate from BHQ 1 and emit strong fluorescence. Using the nicking enzyme, the fluorescence signals of the biosensor are greatly amplified. The biosensor exhibited a linear relationship with the concentration of S. enteritidis ranging from 10(2) to 3 × 10(3)CFU/mL in water and from 1.5 × 10(2) to 3 × 10(3)CFU/mL in milk. The present results indicate that our FRET-based detection system can be widely employed for the effective detection of pathogens. PMID:24434495

  7. Laser damage thresholds of bone objects

    NASA Astrophysics Data System (ADS)

    Ostrowski, Roman; Marczak, Jan; Strzelec, Marek; Koss, Andrzej

    2007-07-01

    The main aim of laser cleaning is removal of encrustation without damage of original artwork substrate material. Art object are often made of fragile and breakage vulnerable materials, for which laser cleaning is an irreplaceable technique. The same applies to figures and sculptures made of different kinds of bones, so it is needed to determine damage threshold values of laser fluency. The paper, therefore, presents the results of investigations of pulse laser radiation interaction with bovine bones, ivory and bear tusk, utilizing different harmonic wavelengths of Nd:YAG laser in a wide range of fluences. It includes fundamental wavelength of 1064 nm with maximum energy of 500 mJ and harmonics: 532 nm (250 mJ) and 355 nm (90 mJ), generated by ReNOVALaser 5 system. Laser fluency has been controlled by means of direct energy variations or by radiation focusing at the object (from 8 mm to 300 ?m), using constant pulse duration of 15 ns. Exact determination of bones threshold damage was based on microscopic investigation of the results of laser pulse irradiation.

  8. Updated LPI Thresholds for the Nike Laser*

    NASA Astrophysics Data System (ADS)

    Weaver, J. L.; Oh, J.; Afeyan, B.; Phillips, L.; Seely, J.; Kehne, D.; Brown, C.; Obenschain, S. P.; Serlin, V.; Schmitt, A. J.; Feldman, U.; Holland, G.; Manka, C.; Lehmberg, R. H.; McLean, E.

    2009-11-01

    Advanced implosion designs for direct drive inertial confinement fusion use high laser intensities (10^15-10^16 W/cm^2) to achieve gain (g>100) with a reduction in total laser energy (E<1 MJ). Krypton-fluoride lasers such as the Nike laser at NRL are an attractive choice due to their combination of short wavelength (248 nm), large bandwidth (1-2 THz), and beam smoothing by induced spatial incoherence but the potential threat from laser-plasma instabilities (LPI) needs to be assessed. The 2008 LPI campaign at Nike yielded threshold intensities above 10^15 W/cm^2 for the two-plasmon instability, a value higher than reported for 351 nm glass lasers. The experiments used a planar geometry, solid polystyrene targets, and a subset of beams (E<200 J) with a reduced focal spot (d<125 ?m). The 2009 campaign extended the shot parameters to higher laser energies (E<1 kJ) and larger spot sizes (d<300 ?m). Spectrally-resolved and time-resolved measurements of x-rays and emission near ^1/2?o and ^3/2?o harmonics of the laser wavelength show threshold intensities consistent with the 2008 results. *Work supported by DoE/NNSA

  9. Conceptual problems in detecting the evolution of dark energy when using distance measurements

    NASA Astrophysics Data System (ADS)

    Bolejko, K.

    2011-01-01

    Context. Dark energy is now one of the most important and topical problems in cosmology. The first step to reveal its nature is to detect the evolution of dark energy or to prove beyond doubt that the cosmological constant is indeed constant. However, in the standard approach to cosmology, the Universe is described by the homogeneous and isotropic Friedmann models. Aims: We aim to show that in the perturbed universe (even if perturbations vanish if averaged over sufficiently large scales) the distance-redshift relation is not the same as in the unperturbed universe. This has a serious consequence when studying the nature of dark energy and, as shown here, can impair the analysis and studies of dark energy. Methods: The analysis is based on two methods: the linear lensing approximation and the non-linear Szekeres Swiss-Cheese model. The inhomogeneity scale is ~50 Mpc, and both models have the same density fluctuations along the line of sight. Results: The comparison between linear and non-linear methods shows that non-linear corrections are not negligible. When inhomogeneities are present the distance changes by several percent. To show how this change influences the measurements of dark energy, ten future observations with 2% uncertainties are generated. It is shown the using the standard methods (i.e. under the assumption of homogeneity) the systematics due to inhomogeneities can distort our analysis, and may lead to a conclusion that dark energy evolves when in fact it is constant (or vice versa). Conclusions: Therefore, if future observations are analysed only within the homogeneous framework then the impact of inhomogeneities (such as voids and superclusters) can be mistaken for evolving dark energy. Since the robust distinction between the evolution and non-evolution of dark energy is the first step to understanding the nature of dark energy a proper handling of inhomogeneities is essential.

  10. Aerospect operations criteria for Mercury thresholds

    NASA Technical Reports Server (NTRS)

    Katz, S.

    1979-01-01

    The hazards anticipated from a large scale mercury spill during a possible failure in the preflight and early flight stages of the Space Shuttle were studied. Toxicity thresholds were investigated as well as other consequences of mercury interacting with the environment. Three sites of mercury spill were investigated: land, water, and atmosphere. A laboratory study of interactions between mercury vapor and ozone in a low pressure, high ultraviolet radiation environment approximated the conditions of a mercury vapor release in the ozone layer region of the stratosphere. Clear evidence of an interaction leading to the destruction of ozone by conversion to oxygen was obtained. The impact of a spill on the Earth's environment and methods of early detection of a developing hazard wave of primary concern in the study.

  11. Measurement of the reaction near threshold

    E-print Network

    Smyrski, J; Budzanowski, A; Czerwinski, E; Czyzykiewicz, R; Gil, D; Grzonka, D; Janusz, M; Jarczyk, L; Kamys, B; Khoukaz, A; Klaja, P; Mersmann, T; Moskal, P; Oelert, W; Piskor-Ignatowicz, C; Przerwa, J; Rejdych, B; Ritman, J; Rozek, T; Sefzick, T; Siemaszko, M; Täschner, A; Winter, P; Wolke, M; Wüstner, P; Zipper, W

    2007-01-01

    Total and differential cross sections for the dp $\\to 3He eta reaction have been measured near threshold for 3He center-of-mass momenta in the range from 17.1 MeV/c to 87.5 MeV/c. The data were taken during a slow ramping of the COSY internal deuteron beam scattered on a proton target detecting the 3He ejectiles with the COSY-11 facility. The forward-backward asymmetries of the differential cross sections deviate clearly from zero for center-of-mass momenta above 50 MeV/c indicating the presence of higher partial waves in the final state. Below 50 MeV/c center-of-mass momenta a fit of the final state enhancement factor to the data of the total cross sections results in the 3He eta scattering length of a = |2.9 +/- 0.6| + i (3.2 +/- 0.4) fm.

  12. Open strangeness threshold production at COSY-11

    E-print Network

    Winter, P; Budzanowski, A; Czyzykiewicz, R; Grzonka, D; Janusz, M; Jarczyk, L; Kamys, B; Khoukaz, A; Kilian, K; Klaja, P; Moskal, P; Oelert, W; Piskor-Ignatowicz, C; Przerwa, J; Rozek, T; Sefzick, T; Siemaszko, M; Smyrski, J; Strzalkowski, A; Täschner, A; Wolke, M; Wüstner, P; Zipper, W

    2004-01-01

    The open strangeness production near threshold is investigated at the internal experiment COSY-11 in different reaction channels. Recently, the main focus has been to extend measurements of the hyperon production pp->pK+Lambda/Sigma0 in different isospin channels as well as the associated strangeness production in pp->ppK+K-. The experimental technique is based on the reconstruction of the four momentum for all positively charged ejectiles. Neutrons are detected in addition using a neutral particle detector. The unregistered hyperon or meson is identified by means of the missing mass technique. The present status of the analysis for both reaction channels is presented. In case of the reaction pp->ppK+K-, very preliminary cross sections are shown.

  13. Detection of Human Impacts by an Adaptive Energy-Based Anisotropic Algorithm

    PubMed Central

    Prado-Velasco, Manuel; Ortiz Marín, Rafael; del Rio Cidoncha, Gloria

    2013-01-01

    Boosted by health consequences and the cost of falls in the elderly, this work develops and tests a novel algorithm and methodology to detect human impacts that will act as triggers of a two-layer fall monitor. The two main requirements demanded by socio-healthcare providers—unobtrusiveness and reliability—defined the objectives of the research. We have demonstrated that a very agile, adaptive, and energy-based anisotropic algorithm can provide 100% sensitivity and 78% specificity, in the task of detecting impacts under demanding laboratory conditions. The algorithm works together with an unsupervised real-time learning technique that addresses the adaptive capability, and this is also presented. The work demonstrates the robustness and reliability of our new algorithm, which will be the basis of a smart falling monitor. This is shown in this work to underline the relevance of the results. PMID:24157505

  14. Detection of ?-Amyloid Peptide Dimer in Solution by Fluorescence Resonance Energy Transfer

    NASA Astrophysics Data System (ADS)

    Han, Jun; Mei, Erwen; Kung, Mei-Ping; Kung, Hank; Dai, Hai-Lung

    2006-03-01

    Studies have suggested that there is a connection between ß-amyloid-derived diffusible ligands (ADDLs), small oligomers formed from clustering of peptides with 39-42 amino acid units, and pathogenicity of Alzheimer's disease. It is believed that the soluble ADDL oligomers eventually coagulate and precipitate into fibrils that cause neurotoxicity. Although there have been studies characterizing the fibrils structure and the large coagulate formation kinetics, little experimental information exists for the oligomers in the solution phase. We report here the use of fluorescence resonance energy transfer detected through a confocal microscope under single molecule conditions for the detection of the ?-amyloid (1-40) peptide dimer in solution. The structure of the dimer is characterized in terms of the distance of the two N-terminals.

  15. Sensitive turn-on fluorescent detection of melamine based on fluorescence resonance energy transfer.

    PubMed

    Guo, Liangqia; Zhong, Jianhai; Wu, Jinmei; Fu, FengFu; Chen, Guonan; Chen, Yongxuan; Zheng, Xiaoyan; Lin, Song

    2011-04-21

    We here report a novel fluorescent method for the detection of melamine based on the high fluorescence quenching ability of gold nanoparticles. The fluorescence was significantly quenched via fluorescence resonance energy transfer when fluorescein molecules were attached to the surface of gold nanoparticles by electrostatic interaction. Upon addition of melamine, the fluorescence was enhanced due to the competitive adsorption of gold nanoparticles between melamine and fluorescein. Under the optimum conditions, the fluorescence enhancement efficiency [(I-I(0))/I(0)] showed a linear relationship with the concentration of melamine in the range of 1.0 × 10(-7) mol L(-1)~4.0 × 10(-6) mol L(-1), and the detection limit was calculated to be 1.0 × 10(-9) mol L(-1). The proposed method showed several advantages such as high sensitivity, short analysis time, low cost and ease of operation. PMID:21359305

  16. A new understanding of multiple-pulsed laser-induced retinal injury thresholds.

    PubMed

    Lund, David J; Sliney, David H

    2014-04-01

    Laser safety standards committees have struggled for years to formulate adequately a sound method for treating repetitive-pulse laser exposures. Safety standards for lamps and LEDs have ignored this issue because averaged irradiance appeared to treat the issue adequately for large retinal image sizes and skin exposures. Several authors have recently questioned the current approach of three test conditions (i.e., limiting single-pulse exposure, average irradiance, and a single-pulse-reduction factor) as still insufficient to treat pulses of unequal energies or certain pulse groupings. Schulmeister et al. employed thermal modeling to show that a total-on-time pulse (TOTP) rule was conservative. Lund further developed the approach of probability summation proposed by Menendez et al. to explain pulse-additivity, whereby additivity is the result of an increasing probability of detecting injury with multiple pulse exposures. This latter argument relates the increase in detection probability to the slope of the probit curve for the threshold studies. Since the uncertainty in the threshold for producing an ophthalmoscopically detectable minimal visible lesion (MVL) is large for retinal exposure to a collimated laser beam, safety committees traditionally applied large risk reduction factors ("safety factors") of one order of magnitude when deriving intrabeam, "point-source" exposure limits. This reduction factor took into account the probability of visually detecting the low-contrast lesion among other factors. The reduction factor is smaller for large spot sizes where these difficulties are quite reduced. Thus the N??·²? reduction factor may result from the difficulties in detecting the lesion. Recent studies on repetitive pulse exposures in both animal and in vitro (retinal explant) models support this interpretation of the available data. PMID:24562071

  17. Contraband detection using high-energy gamma rays from {sup 16}O*

    SciTech Connect

    Micklich, B.J.; Fink, C.L.; Sagalovsky, L.; Smith, D.L. [Argonne National Lab., IL (United States). Technology Development Div.

    1996-12-01

    High-energy monoenergetic gamma rays (6.13 and 7.12 MeV) from the decay of excited states of the {sup 16}O* nucleus are highly penetrating and thus offer potential for non-intrusive inspection of loaded containers for narcotics, explosives, and other contraband items. These excited states can be produced by irradiation of water with 14-MeV neutrons from a DT neutron generator or through the {sup 19}F(p,{alpha}){sup 16}O* reaction. Resonances in {sup 19}F(p,{alpha}){sup 16}O* at proton energies between 340 keV and 2 MeV allow use of a low-energy accelerator to provide a compact, portable gamma source of reasonable intensity. The present work provides estimates of gamma source parameters and suggests how various types of contraband could be detected. Gamma rays can be used to perform transmission or emission radiography of containers or other objects. Through the use of ({gamma}, n) and ({gamma}, fission) reactions, this technique is also capable of detecting special nuclear materials such as deuterium, lithium, beryllium, uranium, and plutonium. Analytic and Monte Carlo techniques are used to model empty and loaded container inspection for accelerator-produced gamma, radioisotope, and x-ray sources.

  18. Contraband detection using high-energy gamma rays from 16O*

    NASA Astrophysics Data System (ADS)

    Micklich, Bradley J.; Fink, Charles L.; Sagalovsky, Leonid; Smith, Donald L.

    1997-02-01

    High-energy monoenergetic gamma rays (6.13 and 7.12 MeV) from the decay of excited states of the 16O* nucleus are highly penetrating and thus offer potential for non- intrusive inspection of loaded containers for narcotics, explosives, and other contraband items. These excited states can be produced by irradiation of water with 14-MeV neutrons from a DT neutron generator or through the 19F(p,alpha)16O* reaction. Resonances in 19F(p,alpha)16O* at proton energies between 340 keV and 2 MeV allow use of a low-energy accelerator to provide a compact, portable gamma source of reasonable intensity. The present work provides estimates of gamma source parameters and suggests how various types of contraband could be detected. Gamma rays can be used to perform transmission or emission radiography of containers or other objects. Through the use of (gamma,n) and (gamma,fission) reactions, this technique is also capable of detecting special nuclear materials such as deuterium, lithium, beryllium, uranium, and plutonium. Analytic and Monte Carlo techniques are used to model empty and loaded container inspection for accelerator-produced gamma, radioisotope, and x-ray sources.

  19. Direction discrimination thresholds of vestibular and cerebellar nuclei neurons.

    PubMed

    Liu, Sheng; Yakusheva, Tatyana; Deangelis, Gregory C; Angelaki, Dora E

    2010-01-13

    To understand the roles of the vestibular system in perceptual detection and discrimination of self-motion, it is critical to account for response variability in computing the sensitivity of vestibular neurons. Here we study responses of neurons with no eye movement sensitivity in the vestibular (VN) and rostral fastigial nuclei (FN) using high-frequency (2 Hz) oscillatory translational motion stimuli. The axis of translation (i.e., heading) varied slowly (1 degrees /s) in the horizontal plane as the animal was translated back and forth. Signal detection theory was used to compute the threshold sensitivity of VN/FN neurons for discriminating small variations in heading around all possible directions of translation. Across the population, minimum heading discrimination thresholds averaged 16.6 degrees +/- 1 degrees SE for FN neurons and 15.3 degrees +/- 2.2 degrees SE for VN neurons, severalfold larger than perceptual thresholds for heading discrimination. In line with previous studies and theoretical predictions, maximum discriminability was observed for directions where firing rate changed steeply as a function of heading, which occurs at headings approximately perpendicular to the maximum response direction. Forward/backward heading thresholds tended to be lower than lateral motion thresholds, and the ratio of lateral over forward heading thresholds averaged 2.2 +/- 6.1 (geometric mean +/- SD) for FN neurons and 1.1 +/- 4.4 for VN neurons. Our findings suggest that substantial pooling and/or selective decoding of vestibular signals from the vestibular and deep cerebellar nuclei may be important components of further processing. Such a characterization of neural sensitivity is critical for understanding how early stages of vestibular processing limit behavioral performance. PMID:20071508

  20. The design of an intense accelerator-based epithermal neutron beam prototype for BNCT using near-threshold reactions

    Microsoft Academic Search

    Charles L. Lee

    1998-01-01

    Near-threshold boron neutron capture therapy (BNCT) uses proton energies only tens of rev above the (pan) reaction threshold in lithium in order to reduce the moderation requirements of the neutron source. The goals of this research were to prove the feasibility of this near-threshold concept for BNCT applications, using both calculation and experiment, and design a compact neutron source prototype

  1. Coordinated Activation and Reporting for Energy-Efficient Target Intrusion Detection, Tracking, and Reporting in Wireless Sensor Networks

    E-print Network

    Vokkarane, Vinod M.

    Coordinated Activation and Reporting for Energy-Efficient Target Intrusion Detection, Tracking-efficient target monitoring (detection, tracking, and re- porting) in WSNs. Our approach aims to minimize outlines the problem description and Section III describes the related background work on target-tracking

  2. Extreme Sensitivity and the Practical Implications of Risk Assessment Thresholds

    PubMed Central

    Bukowski, John; Nicolich, Mark; Lewis, R. Jeffrey

    2013-01-01

    Traditional risk-assessment theory assumes the existence of a threshold for non-cancer health effects. However, a recent trend in environmental regulation rejects this assumption in favor of non-threshold linearity for these endpoints. This trend is driven largely by two related concepts: (1) a theoretical assumption of wide-ranging human sensitivity, and (2) inability to detect thresholds in epidemiologic models. Wide-ranging sensitivity assumes a subpopulation with extreme background vulnerability, so that even trivial environmental exposures are hazardous to someone somewhere. We use examples from the real world of clinical medicine to show that this theoretical assumption is inconsistent with the biology of mammalian systems and the realities of patient care. Using examples from particulate-matter air-pollution research, we further show that failure to reject linearity is usually driven by statistical rather than biological considerations, and that nonlinear/threshold models often have a similar or better fit than their linear counterparts. This evidence suggests the existence of practical, real-world thresholds for most chemical exposures. PMID:23930098

  3. Proton-threshold states in 28Si

    NASA Astrophysics Data System (ADS)

    Champagne, A. E.; Pitt, M. L.; Zhang, P. H.; Lee, L. L.; Levine, M. J.

    1986-10-01

    The 27Al(3He, d)28Si reaction has been used to locate candidates for resonances in the 27Al + p system residing near the proton-capture threshold in the energy region characteristic of quiescent stellar hydrogen burning. Two such states are observed at excitation energies Ex = 11.658 MeV(J? = 2+) and 11.671 MeV (J? = 1-). A comparison of the cross sections for the 27Al(3He, d)28Si and the 27Al(?, t)28Si reactions implies angular-momentum transfers of l = 2 and l = 3, respectively, for the two states of interest. Using this result, an astrophysically significant upper limit on the thermonuclear reaction rate has been calculated for the 27Al(p, ?)28Si reaction which is found to be too slow to affect the 27Al abundance in red giants.

  4. Rigid-floppy percolation threshold.

    PubMed

    Avramov, I

    2009-05-27

    The mathematical limits for the percolation of rigid and floppy clusters throughout continuous networks are considered. Results are compared to the previous prediction of Thorpe based on the assumption that the threshold condition is the equality of degrees of freedom and the number of constraints. It is demonstrated that, in two-dimensional systems, the thresholds values predicted here and in the Thorpe model are relatively close. Our investigation demonstrates that, in 3D, there is a range of strong bond concentrations in which both floppy and rigid clusters percolate simultaneously. Depending on the particular property, either the rigid or the floppy cluster plays the key role. This explains the existence of solid electrolytes. They are solid because of the percolating rigid skeleton and at the same time have high conductivity controlled by the floppy cluster that also percolates. PMID:21825548

  5. Chloride thresholds in marine concrete

    SciTech Connect

    Thomas, M. [Univ. of Toronto, Ontario (Canada). Dept. of Civil Engineering] [Univ. of Toronto, Ontario (Canada). Dept. of Civil Engineering

    1996-04-01

    This paper reports results from an ongoing study of the performance of fly ash concrete in marine exposure. Reinforced concrete specimens exposed to tidal conditions were retrieved at ages ranging from 1 to 4 years. Steel reinforcement mass losses are compared with chloride contents at the location of the bar for concrete specimens of various strength grades and with a range of fly ash levels. The maximum level of chloride that could be tolerated without significant mass loss due to corrosion was found to vary with fly ash content. This threshold chloride level decreased with increasing fly ash content; values obtained were 0.70%, 0.65%, 0.50% and 0.20% acid-soluble chloride (by mass of cementitious material) for concrete with 0%, 15%, 30% and 50% ash, respectively. Despite the lower threshold values, fly ash concrete was found to provide better protection to the steel under these conditions, due to its increased resistance to chloride ion penetration.

  6. ISODATA: Thresholds for splitting clusters

    NASA Technical Reports Server (NTRS)

    Kan, E. P. F. (principal investigator)

    1972-01-01

    The author has identified the following significant results. The parameter AD (average distance) as used in the ISODATA program was critically examined. Thresholds of AD to decide on the splitting of clusters were obtained. For the univariate case, 0.84 was established as a sound choice, after examining several simple, as well as composite, distributions and also after investigating the probability of misclassification when points have to be reassigned to the newly identified clusters. For the multivariate case, the empirical threshold (N-0.16)/square root of N was extrapolated. A final criticism on AD was that AD would lose its effectiveness as a discriminative measure for the present purpose when N was large.

  7. Automated identification of exudates and optic disc based on inverse surface thresholding.

    PubMed

    Yazid, Haniza; Arof, Hamzah; Isa, Hazlita Mohd

    2012-06-01

    This paper presents a new approach to detect exudates and optic disc from color fundus images based on inverse surface thresholding. The strategy involves the applications of fuzzy c-means clustering, edge detection, otsu thresholding and inverse surface thresholding. The main advantage of the proposed approach is that it does not depend on manually selected parameters that are normally chosen to suit the tested databases. When applied to two sets of databases the proposed method outperforms a method based on watershed segmentation. PMID:21318328

  8. Roots at the Percolation Threshold

    NASA Astrophysics Data System (ADS)

    Kroener, E.; Ahmed, M. A.; Kaestner, A.; Vontobel, P.; Zarebanadkouki, M.; Carminati, A.

    2014-12-01

    Much of the carbon assimilated by plants during photosynthesis is lost to the soil via rhizodepositions. One component of rhizopdeposition is mucilage, a hydrogel that dramatically alters the soil physical properties. Mucilage was assumed to explain unexpectedly low rhizosphere rewetting rates during irrigation (Carminati et al. 2010) and temporarily water repellency in the rhizosphere after severe drying (Moradi et al. 2012).Here, we present an experimental and theoretical study for the rewetting behaviour of a soil mixed with mucilage, which was used as an analogue of the rhizosphere. Our samples were made of two layers of untreated soils separated by a thin layer (ca. 1 mm) of soil treated with mucilage. We prepared soil columns of varying particle size, mucilage concentration and height of the middle layer above the water table. The dry soil columns were re-wetted by capillary rise from the bottom.The rewetting of the middle layer showed a distinct dual behavior. For mucilage concentrations lower than a certain threshold, water could cross the thin layer almost immediately after rewetting of bulk soil. At slightly higher mucilage concentrations, the thin layer was almost impermeable. The mucilage concentration at the threshold strongly depended on particle size: the smaller the particle size the larger the soil specific surface and the more mucilage was needed to cover the entire particle surface and to induce water repellency.We applied a classic pore network model to simulate the experimental observations. In the model a certain fraction of nodes were randomly disconnected to reproduce the effect of mucilage in temporarily blocking the flow. The percolation model could qualitatively reproduce well the threshold characteristics of the experiments. Our experiments, together with former observations of water dynamics in the rhizosphere, suggest that the rhizosphere is near the percolation threshold, where small variations in mucilage concentration sensitively alter the soil hydraulic conductivity. Is mucilage exudation a plant mechanism to efficiently control the rhizosphere conductivity and the access to water?

  9. Laser threshold reduction in a spintronic device

    Microsoft Academic Search

    J. Rudolph; D. Hugele; M. Oestreich; H. M. Gibbs; G. Khitrova

    2004-01-01

    We experimentally demonstrate a threshold reduction of a semiconductor laser by optically pumping with spin-polarized electrons. Calculations show that a threshold reduction by 50% is possible even for electrically pumped lasers.

  10. 40 CFR 98.471 - Reporting threshold.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ...2012-07-01 2012-07-01 false Reporting threshold. 98.471 Section 98.471 Protection...MANDATORY GREENHOUSE GAS REPORTING Injection of Carbon Dioxide § 98.471 Reporting threshold. (a) You must report under this...

  11. 40 CFR 98.421 - Reporting threshold.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ...2010-07-01 2010-07-01 false Reporting threshold. 98.421 Section 98.421 Protection...MANDATORY GREENHOUSE GAS REPORTING Suppliers of Carbon Dioxide § 98.421 Reporting threshold. Any supplier of CO2 who meets...

  12. 40 CFR 98.471 - Reporting threshold.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ...2013-07-01 2013-07-01 false Reporting threshold. 98.471 Section 98.471 Protection...MANDATORY GREENHOUSE GAS REPORTING Injection of Carbon Dioxide § 98.471 Reporting threshold. (a) You must report under this...

  13. 40 CFR 98.421 - Reporting threshold.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ...2014-07-01 2014-07-01 false Reporting threshold. 98.421 Section 98.421 Protection...MANDATORY GREENHOUSE GAS REPORTING Suppliers of Carbon Dioxide § 98.421 Reporting threshold. Any supplier of CO2 who meets...

  14. 40 CFR 98.471 - Reporting threshold.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ...2011-07-01 2011-07-01 false Reporting threshold. 98.471 Section 98.471 Protection...MANDATORY GREENHOUSE GAS REPORTING Injection of Carbon Dioxide § 98.471 Reporting threshold. (a) You must report under this...

  15. 40 CFR 98.421 - Reporting threshold.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ...2011-07-01 2011-07-01 false Reporting threshold. 98.421 Section 98.421 Protection...MANDATORY GREENHOUSE GAS REPORTING Suppliers of Carbon Dioxide § 98.421 Reporting threshold. Any supplier of CO2 who meets...

  16. Theory of Mesoscopic Threshold Detectors of non-Gaussian Noise

    NASA Astrophysics Data System (ADS)

    Jordan, Andrew

    2009-03-01

    Recently, measurements of current fluctuations arising from the charge discreteness (shot noise) have become an invaluable tool in mesoscopic physics, the most noticeable achievement being the measurement of quasi-particle charge in the fractional quantum Hall state. Typically, shot noise experiments report measurements of the zero-frequency noise power, which is a characteristic of the Gaussian component of current fluctuations. A natural generalization of the noise power, the counting statistics of charge transmitted through a system, is interesting in itself, because it contains complete information about the electron transport on a long time scale. However, the measurement of non-Gaussian noise effects presents an experimental challenge because of the limitations imposed by the central limit theorem. This difficulty can be partly overcome by placing an auxiliary mesoscopic system (detector) very close to the noise source and arranging strong coupling to the noise. This leads to the idea of a threshold detector, which is able to measure rare current fluctuations. Its basic principle is analogous to a pole vault: A detection event occurs when the measured system variable exceeds a given threshold value. A natural candidate for such a threshold detector is a metastable system operating on an activation principle. By measuring the rate of switching out of the metastable state, information about the statistical properties of the noise driving the system may be extracted. This requires solving the Kramers' problem of noise-activated escape from a metastable state beyond the Gaussian noise approximation and investigating how the measurement circuit affects threshold detection.

  17. Optimization of dual energy contrast enhanced breast tomosynthesis for improved mammographic lesion detection and diagnosis

    NASA Astrophysics Data System (ADS)

    Saunders, R.; Samei, E.; Badea, C.; Yuan, H.; Ghaghada, K.; Qi, Y.; Hedlund, L. W.; Mukundan, S.

    2008-03-01

    Dual-energy contrast-enhanced breast tomosynthesis has been proposed as a technique to improve the detection of early-stage cancer in young, high-risk women. This study focused on optimizing this technique using computer simulations. The computer simulation used analytical calculations to optimize the signal difference to noise ratio (SdNR) of resulting images from such a technique at constant dose. The optimization included the optimal radiographic technique, optimal distribution of dose between the two single-energy projection images, and the optimal weighting factor for the dual energy subtraction. Importantly, the SdNR included both anatomical and quantum noise sources, as dual energy imaging reduces anatomical noise at the expense of increases in quantum noise. Assuming a tungsten anode, the maximum SdNR at constant dose was achieved for a high energy beam at 49 kVp with 92.5 ?m copper filtration and a low energy beam at 49 kVp with 95 ?m tin filtration. These analytical calculations were followed by Monte Carlo simulations that included the effects of scattered radiation and detector properties. Finally, the feasibility of this technique was tested in a small animal imaging experiment using a novel iodinated liposomal contrast agent. The results illustrated the utility of dual energy imaging and determined the optimal acquisition parameters for this technique. This work was supported in part by grants from the Komen Foundation (PDF55806), the Cancer Research and Prevention Foundation, and the NIH (NCI R21 CA124584-01). CIVM is a NCRR/NCI National Resource under P41-05959/U24-CA092656.

  18. Method for detecting point mutations in DNA utilizing fluorescence energy transfer

    DOEpatents

    Parkhurst, Lawrence J. (Lincoln, NE); Parkhurst, Kay M. (Lincoln, NE); Middendorf, Lyle (Lincoln, NE)

    2001-01-01

    A method for detecting point mutations in DNA using a fluorescently labeled oligomeric probe and Forster resonance energy transfer (FRET) is disclosed. The selected probe is initially labeled at each end with a fluorescence dye, which act together as a donor/acceptor pair for FRET. The fluorescence emission from the dyes changes dramatically from the duplex stage, wherein the probe is hybridized to the complementary strand of DNA, to the single strand stage, when the probe is melted to become detached from the DNA. The change in fluorescence is caused by the dyes coming into closer proximity after melting occurs and the probe becomes detached from the DNA strand. The change in fluorescence emission as a function of temperature is used to calculate the melting temperature of the complex or T.sub.m. In the case where there is a base mismatch between the probe and the DNA strand, indicating a point mutation, the T.sub.m has been found to be significantly lower than the T.sub.m for a perfectly match probelstand duplex. The present invention allows for the detection of the existence and magnitude of T.sub.m, which allows for the quick and accurate detection of a point mutation in the DNA strand and, in some applications, the determination of the approximate location of the mutation within the sequence.

  19. Automated Detection and Analysis of Ca2+ Sparks in x-y Image Stacks Using a Thresholding Algorithm Implemented within the Open-Source Image Analysis Platform ImageJ

    PubMed Central

    Steele, Elliot M.; Steele, Derek S.

    2014-01-01

    Previous studies have used analysis of Ca2+ sparks extensively to investigate both normal and pathological Ca2+ regulation in cardiac myocytes. The great majority of these studies used line-scan confocal imaging. In part, this is because the development of open-source software for automatic detection of Ca2+ sparks in line-scan images has greatly simplified data analysis. A disadvantage of line-scan imaging is that data are collected from a single row of pixels, representing only a small fraction of the cell, and in many instances x-y confocal imaging is preferable. However, the limited availability of software for Ca2+ spark analysis in two-dimensional x-y image stacks presents an obstacle to its wider application. This study describes the development and characterization of software to enable automatic detection and analysis of Ca2+ sparks within x-y image stacks, implemented as a plugin within the open-source image analysis platform ImageJ. The program includes methods to enable precise identification of cells within confocal fluorescence images, compensation for changes in background fluorescence, and options that allow exclusion of events based on spatial characteristics. PMID:24507597

  20. Wavelet thresholding for multiple noisy image copies

    Microsoft Academic Search

    S. Grace Chang; Bin Yu; Martin Vetterli

    2000-01-01

    This correspondence addresses the recovery of an image from its multiple noisy copies. The standard method is to compute the weighted average of these copies. Since the wavelet thresholding technique has been shown to effectively denoise a single noisy copy, we consider in this paper combining the two operations of averaging and thresholding. Because thresholding is a nonlinear technique, averaging