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Sample records for partial shadowing detection

  1. Spectral anomaly detection in deep shadows.

    PubMed

    Kanaev, Andrey V; Murray-Krezan, Jeremy

    2010-03-20

    Although several hyperspectral anomaly detection algorithms have proven useful when illumination conditions provide for enough light, many of these same detection algorithms fail to perform well when shadows are also present. To date, no general approach to the problem has been demonstrated. In this paper, a novel hyperspectral anomaly detection algorithm that adapts the dimensionality of the spectral detection subspace to multiple illumination levels is described. The novel detection algorithm is applied to reflectance domain hyperspectral data that represents a variety of illumination conditions: well illuminated and poorly illuminated (i.e., shadowed). Detection results obtained for objects located in deep shadows and light-shadow transition areas suggest superiority of the novel algorithm over standard subspace RX detection. PMID:20300158

  2. Tricolor attenuation model for shadow detection.

    PubMed

    Tian, Jiandong; Sun, Jing; Tang, Yandong

    2009-10-01

    Shadows, the common phenomena in most outdoor scenes, bring many problems in image processing and computer vision. In this paper, we present a novel method focusing on extracting shadows from a single outdoor image. The proposed tricolor attenuation model (TAM) that describe the attenuation relationship between shadow and its nonshadow background is derived based on image formation theory. The parameters of the TAM are fixed by using the spectral power distribution (SPD) of daylight and skylight, which are estimated according to Planck's blackbody irradiance law. Based on the TAM, a multistep shadow detection algorithm is proposed to extract shadows. Compared with previous methods, the algorithm can be applied to process single images gotten in real complex scenes without prior knowledge. The experimental results validate the performance of the model. PMID:19586816

  3. Automatic Shadow Detection and Removal from a Single Image.

    PubMed

    Khan, Salman H; Bennamoun, Mohammed; Sohel, Ferdous; Togneri, Roberto

    2016-03-01

    We present a framework to automatically detect and remove shadows in real world scenes from a single image. Previous works on shadow detection put a lot of effort in designing shadow variant and invariant hand-crafted features. In contrast, our framework automatically learns the most relevant features in a supervised manner using multiple convolutional deep neural networks (ConvNets). The features are learned at the super-pixel level and along the dominant boundaries in the image. The predicted posteriors based on the learned features are fed to a conditional random field model to generate smooth shadow masks. Using the detected shadow masks, we propose a Bayesian formulation to accurately extract shadow matte and subsequently remove shadows. The Bayesian formulation is based on a novel model which accurately models the shadow generation process in the umbra and penumbra regions. The model parameters are efficiently estimated using an iterative optimization procedure. Our proposed framework consistently performed better than the state-of-the-art on all major shadow databases collected under a variety of conditions. PMID:27046489

  4. An integrated approach for shadow detection of the building in urban areas

    NASA Astrophysics Data System (ADS)

    Zhou, Guoqing; Han, Caiyun; Ye, Siqi; Wang, Yuefeng; Wang, Chenxi

    2015-12-01

    Shadows commonly exist in high resolution image, particularly in urban areas .The presence of shadows can represent a serious obstacle for their full exploitation. Especially, because of the complexity of the urban circumstance, there are some factors effecting the shadow detection. For example, the high reflectivity ground, or the glass wall of the building, makes shadow somewhere brighter so that it may cause their intensities close to the non-shadow area. In order to solve these problems, we combine the zero-crossing detection method with the DBM-based geometric method of computing the zenith angle of the sun and the altitude angle of the sun .Firstly, the proposed method uses the zero-crossing detection method to detect the edge of the whole image .Then it selects the edges of both the buildings and their shadows by matching the coordinates of DBM. Because the building and its shadow are adjacent, we match these shadows with the ideal shadow gotten by the DBM-based geometric method to get the only shadow of the building. Compared with other methods, this method may detect the shadow areas of the buildings accurately.

  5. The Influence of Cast Shadows on the Detection of Three-Dimensional Curved Contour Structure.

    PubMed

    Khuu, Sieu K; Honson, Vanessa J; Challinor, Kirsten L

    2016-04-01

    Cast shadows have been shown to provide an effective ordinal cue to the depth position of objects. In the present study, two experiments investigated the effectiveness of cast shadows in facilitating the detection of spatial contours embedded in a field of randomly placed elements. In Experiment 1, the separation between the cast shadow and the contour was systematically increased to effectively signal different contour depth positions (relative to background elements), and this was repeated for patterns in which the lighting direction was above and from below. Increasing the shadow separation improved contour detection performance, but the degree to which sensitivity changed was dependent on the lighting direction. Patterns in which the light was from above were better detected than patterns in which the lighting direction was from below. This finding is consistent with the visual system assuming a "light-from-above rule" when processing cast shadows. In Experiment 2, we examined the degree to which changing the shape of the cast shadow (by randomly jittering the position of local cast shadow elements) affected the ability of the visual system to rely on the cast shadow to cue the depth position of the contour. Consistent with a coarse scale analysis, we find that cast shadows remained an effective depth cue even at large degrees of element jitter. Our findings demonstrate that cast shadows provide an effective means of signaling depth, which aids the process of contour integration, and this process is largely tolerant of local variations in lighting direction. PMID:27107019

  6. Shadow Probability of Detection and False Alarm for Median-Filtered SAR Imagery

    SciTech Connect

    Raynal, Ann Marie; Doerry, Armin Walter; Miller, John A.; Bishop, Edward E.; Horndt, Volker

    2014-06-01

    Median filtering reduces speckle in synthetic aperture radar (SAR) imagery while preserving edges, at the expense of coarsening the resolution, by replacing the center pixel of a sliding window by the median value. For shadow detection, this approach helps distinguish shadows from clutter more easily, while preserving shadow shape delineations. However, the nonlinear operation alters the shadow and clutter distributions and statistics, which must be taken into consideration when computing probability of detection and false alarm metrics. Depending on system parameters, median filtering can improve probability of detection and false alarm by orders of magnitude. Herein, we examine shadow probability of detection and false alarm in a homogeneous, ideal clutter background after median filter post-processing. Some comments on multi-look processing effects with and without median filtering are also made.

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

    PubMed

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

    2011-10-01

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

  8. Shadow detection improvement using spectral indices and morphological operators in high resolution images from urban areas

    NASA Astrophysics Data System (ADS)

    Azevedo, S. C.; Silva, E. A.; Pedrosa, M. M.

    2015-04-01

    While high-resolution remote sensing images have increased application possibilities for urban studies, the large number of shadow areas has created challenges to processing and extracting information from these images. Furthermore, shadows can reduce or omit information from the surface as well as degrading the visual quality of images. The pixels of shadows tend to have lower radiance response within the spectrum and are often confused with low reflectance targets. In this work, a shadow detection method was proposed using a morphological operator for dark pattern identification combined with spectral indices. The aims are to avoid misclassification in shadow identification through properties provided by them on color models and, therefore, to improve shadow detection accuracy. Experimental results were tested applying the panchromatic and multispectral band of WorldView-2 image from Sao Paulo city in Brazil, which is a complex urban environment composed by high objects like tall buildings causing large shadow areas. Black top-hat with area injunction was applied in PAN image and shadow identification performance has improved with index as Normalized Difference Vegetation Index (NDVI) and Normalized Saturation-Value Difference Index (NSDVI) ratio from HSV color space obtained from pansharpened multispectral WV-2 image. An increase in distinction between shadows and others objects was observed, which was tested for the completeness, correctness and quality measures computed, using a created manual shadow mask as reference. Therefore, this method can contribute to overcoming difficulties faced by other techniques that need shadow detection as a first necessary preprocessing step, like object recognition, image matching, 3D reconstruction, etc.

  9. Background updating and shadow detection based on spatial, color, and texture information of detected objects

    NASA Astrophysics Data System (ADS)

    Hamad, Ahmed Mahmoud; Tsumura, Norimichi

    2012-05-01

    Background model updating is a vital process for any background subtraction technique. This paper presents an updating mechanism that can be applied efficiently to any background subtraction technique. This updating mechanism exploits the color and spatial features to characterize each detected object. Spatial and color features are used to classify each detected object as a moving background object, a ghost, or a real moving object. The starting position of each detected object is the cue for updating background images. In addition, this paper presents a hybrid scheme to detect and remove cast shadows based on texture and color features. The robustness of the proposed method and its effectiveness in overcoming challenging problems such as gradual and sudden illumination changes, ghost appearance, non-stationary background objects, the stability of moving objects most of the time, and cast shadows are verified quantitatively and qualitatively.

  10. Automatic aerial image shadow detection through the hybrid analysis of RGB and HIS color space

    NASA Astrophysics Data System (ADS)

    Wu, Jun; Li, Huilin; Peng, Zhiyong

    2015-12-01

    This paper presents our research on automatic shadow detection from high-resolution aerial image through the hybrid analysis of RGB and HIS color space. To this end, the spectral characteristics of shadow are firstly discussed and three kinds of spectral components including the difference between normalized blue and normalized red component - BR, intensity and saturation components are selected as criterions to obtain initial segmentation of shadow region (called primary segmentation). After that, within the normalized RGB color space and HIS color space, the shadow region is extracted again (called auxiliary segmentation) using the OTSU operation, respectively. Finally, the primary segmentation and auxiliary segmentation are combined through a logical AND-connection operation to obtain reliable shadow region. In this step, small shadow areas are removed from combined shadow region and morphological algorithms are apply to fill small holes as well. The experimental results show that the proposed approach can effectively detect the shadow region from high-resolution aerial image and in high degree of automaton.

  11. Defining solar park location using shadow over time detection method

    NASA Astrophysics Data System (ADS)

    Martynov, Ivan; Kauranne, Tuomo

    2016-06-01

    There is nowadays a high demand for research on using renewable sources of energy including solar energy. The availability of stable and efficient solar energy is of paramount importance. Therefore, it is vital to install solar panels in locations which are most of the time not in shadow. To illustrate this idea we have developed a shadow identification method for digital elevation models (DEMs) using the computational means of MATLAB whose environment and tools allow fast and easy image processing. As a source of DEMs we use the Shuttle Radar Topography Mission (SRTM) database since it covers most of the terrain of our planet.

  12. Automatic Detection of Clouds and Shadows Using High Resolution Satellite Image Time Series

    NASA Astrophysics Data System (ADS)

    Champion, Nicolas

    2016-06-01

    Detecting clouds and their shadows is one of the primaries steps to perform when processing satellite images because they may alter the quality of some products such as large-area orthomosaics. The main goal of this paper is to present the automatic method developed at IGN-France for detecting clouds and shadows in a sequence of satellite images. In our work, surface reflectance orthoimages are used. They were processed from initial satellite images using a dedicated software. The cloud detection step consists of a region-growing algorithm. Seeds are firstly extracted. For that purpose and for each input ortho-image to process, we select the other ortho-images of the sequence that intersect it. The pixels of the input ortho-image are secondly labelled seeds if the difference of reflectance (in the blue channel) with overlapping ortho-images is bigger than a given threshold. Clouds are eventually delineated using a region-growing method based on a radiometric and homogeneity criterion. Regarding the shadow detection, our method is based on the idea that a shadow pixel is darker when comparing to the other images of the time series. The detection is basically composed of three steps. Firstly, we compute a synthetic ortho-image covering the whole study area. Its pixels have a value corresponding to the median value of all input reflectance ortho-images intersecting at that pixel location. Secondly, for each input ortho-image, a pixel is labelled shadows if the difference of reflectance (in the NIR channel) with the synthetic ortho-image is below a given threshold. Eventually, an optional region-growing step may be used to refine the results. Note that pixels labelled clouds during the cloud detection are not used for computing the median value in the first step; additionally, the NIR input data channel is used to perform the shadow detection, because it appeared to better discriminate shadow pixels. The method was tested on times series of Landsat 8 and Pl

  13. Shadow-insensitive material detection/classification with atmospherically corrected hyperspectral imagery

    NASA Astrophysics Data System (ADS)

    Adler-Golden, Steven M.; Levine, Robert Y.; Matthew, Michael W.; Richtsmeier, Steven C.; Bernstein, Lawrence S.; Gruninger, John H.; Felde, Gerald W.; Hoke, Michael L.; Anderson, Gail P.; Ratkowski-, Anthony

    2001-08-01

    Shadow-insensitive detection or classification of surface materials in atmospherically corrected hyperspectral imagery can be achieved by expressing the reflectance spectrum as a linear combination of spectra that correspond to illumination by the direct sum and by the sky. Some specific algorithms and applications are illustrated using HYperspectral Digital Imagery Collection Experiment (HYDICE) data.

  14. Automated detection framework of the calcified plaque with acoustic shadowing in IVUS images.

    PubMed

    Gao, Zhifan; Guo, Wei; Liu, Xin; Huang, Wenhua; Zhang, Heye; Tan, Ning; Hau, William Kongto; Zhang, Yuan-Ting; Liu, Huafeng

    2014-01-01

    Intravascular Ultrasound (IVUS) is one ultrasonic imaging technology to acquire vascular cross-sectional images for the visualization of the inner vessel structure. This technique has been widely used for the diagnosis and treatment of coronary artery diseases. The detection of the calcified plaque with acoustic shadowing in IVUS images plays a vital role in the quantitative analysis of atheromatous plaques. The conventional method of the calcium detection is manual drawing by the doctors. However, it is very time-consuming, and with high inter-observer and intra-observer variability between different doctors. Therefore, the computer-aided detection of the calcified plaque is highly desired. In this paper, an automated method is proposed to detect the calcified plaque with acoustic shadowing in IVUS images by the Rayleigh mixture model, the Markov random field, the graph searching method and the prior knowledge about the calcified plaque. The performance of our method was evaluated over 996 in-vivo IVUS images acquired from eight patients, and the detected calcified plaques are compared with manually detected calcified plaques by one cardiology doctor. The experimental results are quantitatively analyzed separately by three evaluation methods, the test of the sensitivity and specificity, the linear regression and the Bland-Altman analysis. The first method is used to evaluate the ability to distinguish between IVUS images with and without the calcified plaque, and the latter two methods can respectively measure the correlation and the agreement between our results and manual drawing results for locating the calcified plaque in the IVUS image. High sensitivity (94.68%) and specificity (95.82%), good correlation and agreement (>96.82% results fall within the 95% confidence interval in the Student t-test) demonstrate the effectiveness of the proposed method in the detection of the calcified plaque with acoustic shadowing in IVUS images. PMID:25372784

  15. Automated cloud and shadow detection and filling using two-date Landsat imagery in the United States

    USGS Publications Warehouse

    Jin, Suming; Homer, Collin G.; Yang, Limin; Xian, George; Fry, Joyce; Danielson, Patrick; Townsend, Philip A.

    2013-01-01

    A simple, efficient, and practical approach for detecting cloud and shadow areas in satellite imagery and restoring them with clean pixel values has been developed. Cloud and shadow areas are detected using spectral information from the blue, shortwave infrared, and thermal infrared bands of Landsat Thematic Mapper or Enhanced Thematic Mapper Plus imagery from two dates (a target image and a reference image). These detected cloud and shadow areas are further refined using an integration process and a false shadow removal process according to the geometric relationship between cloud and shadow. Cloud and shadow filling is based on the concept of the Spectral Similarity Group (SSG), which uses the reference image to find similar alternative pixels in the target image to serve as replacement values for restored areas. Pixels are considered to belong to one SSG if the pixel values from Landsat bands 3, 4, and 5 in the reference image are within the same spectral ranges. This new approach was applied to five Landsat path/rows across different landscapes and seasons with various types of cloud patterns. Results show that almost all of the clouds were captured with minimal commission errors, and shadows were detected reasonably well. Among five test scenes, the lowest producer's accuracy of cloud detection was 93.9% and the lowest user's accuracy was 89%. The overall cloud and shadow detection accuracy ranged from 83.6% to 99.3%. The pixel-filling approach resulted in a new cloud-free image that appears seamless and spatially continuous despite differences in phenology between the target and reference images. Our methods offer a straightforward and robust approach for preparing images for the new 2011 National Land Cover Database production.

  16. Vehicle detection based on the use of shadow region and edge

    NASA Astrophysics Data System (ADS)

    Jeong, Sangheon; Kang, Seongkoo; Kim, Joongkyu

    2013-07-01

    Automotive and advanced driver assistance systems have attracted a great deal of attention lately. In these systems, effective and reliable vehicle detection is important because such systems can reduce the number of accidents and save human' lives. This paper describes an approach to detecting a forward vehicle using a camera mounted on the moving vehicle. In this paper, we describe two methods to detect a vehicle on the road. First, by using the vehicle's shadow, we can obtain the general location of the vehicular candidate. Second, we can identify the strong vertical edges at the left and right position of a vehicle. By combining the shadows and the edge, we can detect the vehicle's location. But other regions may also be detected, such as car windows, reflections, and illumination by the sun. In order to remove these other factors, defined as noises, we need to use a filter. After using the filter, we can calculate the exact location of the vehicle. Additionally, by using connected component labeling, we can obtain coordinates and establish the vehicle's location. Connected component labeling find all connected components in an image and assigns a unique label to all points in the same component. These methods are very useful for vehicle detection and the development of the driving assistance systems, and they can protect drivers' safety from having an accident.

  17. Detection of Structural Faults by Modal Data, Lower Bounds and Shadow Sites

    NASA Astrophysics Data System (ADS)

    Contursi, T.; Mangialardi, L. M.; Messina, A.

    1998-02-01

    Different algorithms have recently been developed for the diagnosis of many types of civil and mechanical structures using modal data, such as natural frequencies and mode shapes. Although many solutions have been proposed, some important questions seem to be absent in the technical literature. If changes in a structure's modal parameters are able to reflect structural faults, it is important to know what is the smallest detectable physical change in that structure.It is suggested that damage detection by means of modal data can be useful for macro-damage rather than for micro-damage. This resulted from numerical and experimental tests using a simple correlation between measurement noise and sensitivity of modal data, with respect to structural changes in different parts of a system. An automatic sensitivity approach is presented to obtain the lower bound of structural faults for the particular structure under study. The same automatic procedure is able to detect possible shadow sites within the frequency range analyzed.

  18. Semi-Automated Cloud/shadow Removal and Land Cover Change Detection Using Satellite Imagery

    NASA Astrophysics Data System (ADS)

    Sah, A. K.; Sah, B. P.; Honji, K.; Kubo, N.; Senthil, S.

    2012-08-01

    Multi-platform/sensor and multi-temporal satellite data facilitates analysis of successive change/monitoring over the longer period and there by forest biomass helping REDD mechanism. The historical archive satellite imagery, specifically Landsat, can play an important role for historical trend analysis of forest cover change at national level. Whereas the fresh high resolution satellite, such as ALOS, imagery can be used for detailed analysis of present forest cover status. ALOS satellite imagery is most suitable as it offers data with optical (AVNIR-2) as well as SAR (PALSAR) sensors. AVNIR-2 providing data in multispectral modes play due role in extracting forest information. In this study, a semi-automated approach has been devised for cloud/shadow and haze removal and land cover change detection. Cloud/shadow pixels are replaced by free pixels of same image with the help of PALSAR image. The tracking of pixel based land cover change for the 1995-2009 period in combination of Landsat and latest ALOS data from its AVNIR-2 for the tropical rain forest area has been carried out using Decision Tree Classifiers followed by un-supervised classification. As threshold for tree classifier, criteria of NDVI refined by reflectance value has been employed. The result shows all pixels have been successfully registered to the pre-defined 6 categories; in accordance with IPCC definition; of land cover types with an overall accuracy 80 percent.

  19. Infants' discrimination of shapes from shading and cast shadows.

    PubMed

    Sato, Kazuki; Kanazawa, So; Yamaguchi, Masami K

    2016-07-01

    Shadows are powerful cues in the perception of shapes. We can perceive shading and cast shadow implicitly. We investigated infants' ability to detect a single discrepant figure that was depicted by shading or cast shadow and examined the influence of the contrast polarity of shadows on this process. In Experiment 1, we manipulated the blur direction of a shadow to create stimuli that appeared either to be partially shaded or to cast a shadow and then used a preference to test whether this difference would allow 5- to 8-month-old infants to discriminate the figures that adults were able to perceive as different shapes. Only 7- to-8-month-old infants could differentiate one shading figure from cast shadow figures, and vice versa. In Experiment 2, we reversed the contrast polarity of the figure (dark object with a light shadow) and tested whether discrimination was affected. As has been found with adults, infants exposed to this condition were unable to discriminate the contrast-reversed shading and cast shadow figures. Our results suggested that an age of around 7 months is important for development of the ability to perceive shape differences from shading and cast shadows. PMID:27150615

  20. Vehicle detection using partial least squares.

    PubMed

    Kembhavi, Aniruddha; Harwood, David; Davis, Larry S

    2011-06-01

    Detecting vehicles in aerial images has a wide range of applications, from urban planning to visual surveillance. We describe a vehicle detector that improves upon previous approaches by incorporating a very large and rich set of image descriptors. A new feature set called Color Probability Maps is used to capture the color statistics of vehicles and their surroundings, along with the Histograms of Oriented Gradients feature and a simple yet powerful image descriptor that captures the structural characteristics of objects named Pairs of Pixels. The combination of these features leads to an extremely high-dimensional feature set (approximately 70,000 elements). Partial Least Squares is first used to project the data onto a much lower dimensional sub-space. Then, a powerful feature selection analysis is employed to improve the performance while vastly reducing the number of features that must be calculated. We compare our system to previous approaches on two challenging data sets and show superior performance. PMID:20921579

  1. Multiple symbol partially coherent detection of MPSK

    NASA Technical Reports Server (NTRS)

    Simon, M. K.; Divsalar, D.

    1992-01-01

    It is shown that by using the known (or estimated) value of carrier tracking loop signal to noise ratio (SNR) in the decision metric, it is possible to improve the error probability performance of a partially coherent multiple phase-shift-keying (MPSK) system relative to that corresponding to the commonly used ideal coherent decision rule. Using a maximum-likeihood approach, an optimum decision metric is derived and shown to take the form of a weighted sum of the ideal coherent decision metric (i.e., correlation) and the noncoherent decision metric which is optimum for differential detection of MPSK. The performance of a receiver based on this optimum decision rule is derived and shown to provide continued improvement with increasing length of observation interval (data symbol sequence length). Unfortunately, increasing the observation length does not eliminate the error floor associated with the finite loop SNR. Nevertheless, in the limit of infinite observation length, the average error probability performance approaches the algebraic sum of the error floor and the performance of ideal coherent detection, i.e., at any error probability above the error floor, there is no degradation due to the partial coherence. It is shown that this limiting behavior is virtually achievable with practical size observation lengths. Furthermore, the performance is quite insensitive to mismatch between the estimate of loop SNR (e.g., obtained from measurement) fed to the decision metric and its true value. These results may be of use in low-cost Earth-orbiting or deep-space missions employing coded modulations.

  2. Comparison between color Doppler twinkling artifact and acoustic shadowing for renal calculus detection: an in vitro study.

    PubMed

    Shabana, Wael; Bude, Ronald O; Rubin, Jonathan M

    2009-02-01

    To assess the ability of the color Doppler twinkling artifact to detect renal stones relative to acoustic shadowing, we scanned seven uric acid calculi embedded in a tissue mimicking phantom and in sheep kidneys using a high frequency linear array and a standard curved linear array ultrasound scanheads (L12-5 and C5-2; Philips Ultrasound, Bothel, WA, USA). The stones were scanned in and out of focus. The scans were optimized for shadow formation in gray-scale imaging and for color twinkling in color Doppler imaging. The images were analyzed using Image J (http://rsb.info.nih.gov/ij/). We calculated the contrast to noise ratios (C/N) for the acoustic shadows and the color twinkling artifact compared with background. These measurements were then evaluated using a single factor analysis of variance (ANOVA) and paired two-tailed t tests. With these comparisons, the C/Ns for twinkling were significantly higher than for acoustic shadowing. On average, twinkling produced 19.2 dB greater C/Ns for stones in the phantom and 17.6 dB more for the stones in the kidneys. In addition, ANOVA showed that twinkling is resistant to focusing and scanning frequency differences. The results suggest that the twinkling artifact is a robust method for detecting the presence of renal calculi. The color signature is easier to detect than is acoustic shadowing. Twinkling may be relatively resistant to many of the problems that plague ultrasound examinations for renal stones, i.e., out-of-focus scans that might be caused by beam aberration effects due to patient body habitus. PMID:19041171

  3. Variable Shadow Screens for Imaging Optical Devices

    NASA Technical Reports Server (NTRS)

    Lu, Ed; Chretien, Jean L.

    2004-01-01

    Variable shadow screens have been proposed for reducing the apparent brightnesses of very bright light sources relative to other sources within the fields of view of diverse imaging optical devices, including video and film cameras and optical devices for imaging directly into the human eye. In other words, variable shadow screens would increase the effective dynamic ranges of such devices. Traditionally, imaging sensors are protected against excessive brightness by use of dark filters and/or reduction of iris diameters. These traditional means do not increase dynamic range; they reduce the ability to view or image dimmer features of an image because they reduce the brightness of all parts of an image by the same factor. On the other hand, a variable shadow screen would darken only the excessively bright parts of an image. For example, dim objects in a field of view that included the setting Sun or bright headlights could be seen more readily in a picture taken through a variable shadow screen than in a picture of the same scene taken through a dark filter or a narrowed iris. The figure depicts one of many potential variations of the basic concept of the variable shadow screen. The shadow screen would be a normally transparent liquid-crystal matrix placed in front of a focal-plane array of photodetectors in a charge-coupled-device video camera. The shadow screen would be placed far enough from the focal plane so as not to disrupt the focal-plane image to an unacceptable degree, yet close enough so that the out-of-focus shadows cast by the screen would still be effective in darkening the brightest parts of the image. The image detected by the photodetector array itself would be used as feedback to drive the variable shadow screen: The video output of the camera would be processed by suitable analog and/or digital electronic circuitry to generate a negative partial version of the image to be impressed on the shadow screen. The parts of the shadow screen in front of

  4. Automated detection of cloud and cloud-shadow in single-date Landsat imagery using neural networks and spatial post-processing

    SciTech Connect

    Hughes, Michael J.; Hayes, Daniel J

    2014-01-01

    Use of Landsat data to answer ecological questions is contingent on the effective removal of cloud and cloud shadow from satellite images. We develop a novel algorithm to identify and classify clouds and cloud shadow, \\textsc{sparcs}: Spacial Procedures for Automated Removal of Cloud and Shadow. The method uses neural networks to determine cloud, cloud-shadow, water, snow/ice, and clear-sky membership of each pixel in a Landsat scene, and then applies a set of procedures to enforce spatial rules. In a comparison to FMask, a high-quality cloud and cloud-shadow classification algorithm currently available, \\textsc{sparcs} performs favorably, with similar omission errors for clouds (0.8% and 0.9%, respectively), substantially lower omission error for cloud-shadow (8.3% and 1.1%), and fewer errors of commission (7.8% and 5.0%). Additionally, textsc{sparcs} provides a measure of uncertainty in its classification that can be exploited by other processes that use the cloud and cloud-shadow detection. To illustrate this, we present an application that constructs obstruction-free composites of images acquired on different dates in support of algorithms detecting vegetation change.

  5. Neptune shadows

    NASA Technical Reports Server (NTRS)

    1999-01-01

    This image of Neptune shows the discovery of shadows in Neptune's atmosphere, shadows cast onto a deep cloud band by small elevated clouds. They are the first cloud shadows ever seen by Voyager on any planet. Estimates of the height of these discrete clouds above the underlying cloud bank can be obtained by careful analysis of this data. The Voyager Mission is conducted by JPL for NASA'S Office of Space Science and Applications.

  6. Shadow Play

    ERIC Educational Resources Information Center

    Trundle, Kathy Cabe; Hilson, Margilee P.

    2012-01-01

    A bunny rabbit playfully hops across the wall. Then hands realign and fingers shift to make a hawk soar toward the ceiling. Most children have enjoyed the delightful experience of playing with shadow puppets. The authors build on this natural curiosity to help students link shadows to complex astronomical concepts such as seasons. The…

  7. Cloud shadow speed sensor

    NASA Astrophysics Data System (ADS)

    Fung, V.; Bosch, J. L.; Roberts, S. W.; Kleissl, J.

    2014-06-01

    Changing cloud cover is a major source of solar radiation variability and poses challenges for the integration of solar energy. A compact and economical system is presented that measures cloud shadow motion vectors to estimate power plant ramp rates and provide short-term solar irradiance forecasts. The cloud shadow speed sensor (CSS) is constructed using an array of luminance sensors and a high-speed data acquisition system to resolve the progression of cloud passages across the sensor footprint. An embedded microcontroller acquires the sensor data and uses a cross-correlation algorithm to determine cloud shadow motion vectors. The CSS was validated against an artificial shading test apparatus, an alternative method of cloud motion detection from ground-measured irradiance (linear cloud edge, LCE), and a UC San Diego sky imager (USI). The CSS detected artificial shadow directions and speeds to within 15° and 6% accuracy, respectively. The CSS detected (real) cloud shadow directions and speeds with average weighted root-mean-square difference of 22° and 1.9 m s-1 when compared to USI and 33° and 1.5 m s-1 when compared to LCE results.

  8. Detection of partial polarization of light beams with dipolar nanocubes.

    PubMed

    Leppänen, Lasse-Petteri; Saastamoinen, Kimmo; Lehtolahti, Joonas; Friberg, Ari T; Setälä, Tero

    2016-01-25

    We confirm experimentally that the degree and state of polarization of a random, partially polarized electromagnetic beam can be obtained by probing the field with a nanoscatterer. We use a gold nanocube on silicon substrate as a local scatterer and detect the polarization characteristics of the scattered far field, which enables us to deduce the state of partial polarization of the field at the nanoprobe site. In contrast to previous beam characterization methods where spatial resolution is limited by the pixel size of the detector, the accuracy of the current technique is specified by the particle size. Our work is the first step towards polarization-state detection of random optical near fields for which the use of nanoprobes is required. PMID:26832527

  9. Performance evaluation of partial response continuous phase modulation: Discriminator detection

    NASA Astrophysics Data System (ADS)

    Trachtman, Eyal

    1989-09-01

    The principles of continuous phase modulation (CPM) are reviewed and signalling schemes based on it are discussed. The discriminator detector is widely used to detect CPM signals on band limited channels; it is a non-coherent detector which is widely used in mobile communication applications in which fading makes coherent detection difficult; it is suitable for frequency hopping systems. The detector's inferior response to that of a coherent detector can be compensated by suitable design. The performance is compared of various receivers which use the discriminator detector, using an especially written computer simulation. Receiver schemes considered included: Full response signal with integrate and dump filter; Integrate and dump filter with differential symbol detection; zero forcing linear equalization with symbol detection; Decision feedback equalization (DFE); Maximum likelihood sequence estimation; and Tomlinson filter configuration. The Tomlinson filter configuration, which has not previously been used in a CPM communication system, was compared with the other systems with respect to performance and complexity. For all CPM and detection schemes there are optimum values of h, the modulation index and there is no benefit in increasing the value of h and, therefore the bandwidth, beyond this value. Results are presented for various signal schemes, which indicate that detectability performance can be improved and bandwidth reduced by using a partial response CPM. There is a tradeoff between detectability performance and bandwidth, as a function of the baseband pulse duration. It was found that quaternary signal schemes gave better detectability performance than binary schemes, for the same bit-rates. The simulation results indicated that the Tomlinson-DFE configuration was effective for the partial response M-ary CPM channel with discriminator detection; spectral efficiency was not seriously degraded by precoding using the Tomlinson filter, and there was no

  10. Moving cast shadow resistant for foreground segmentation based on shadow properties analysis

    NASA Astrophysics Data System (ADS)

    Zhou, Hao; Gao, Yun; Yuan, Guowu; Ji, Rongbin

    2015-12-01

    Moving object detection is the fundamental task in machine vision applications. However, moving cast shadows detection is one of the major concerns for accurate video segmentation. Since detected moving object areas are often contain shadow points, errors in measurements, localization, segmentation, classification and tracking may arise from this. A novel shadow elimination algorithm is proposed in this paper. A set of suspected moving object area are detected by the adaptive Gaussian approach. A model is established based on shadow optical properties analysis. And shadow regions are discriminated from the set of moving pixels by using the properties of brightness, chromaticity and texture in sequence.

  11. A Partially Distributed Intrusion Detection System for Wireless Sensor Networks

    PubMed Central

    Cho, Eung Jun; Hong, Choong Seon; Lee, Sungwon; Jeon, Seokhee

    2013-01-01

    The increasing use of wireless sensor networks, which normally comprise several very small sensor nodes, makes their security an increasingly important issue. They can be practically and efficiently secured using intrusion detection systems. Conventional security mechanisms are not usually applicable due to the sensor nodes having limitations of computational power, memory capacity, and battery power. Therefore, specific security systems should be designed to function under constraints of energy or memory. A partially distributed intrusion detection system with low memory and power demands is proposed here. It employs a Bloom filter, which allows reduced signature code size. Multiple Bloom filters can be combined to reduce the signature code for each Bloom filter array. The mechanism could then cope with potential denial of service attacks, unlike many previous detection systems with Bloom filters. The mechanism was evaluated and validated through analysis and simulation.

  12. Lights and shadows of anti-HLA antibodies detected by solid-phase assay.

    PubMed

    Picascia, Antonietta; Sabia, Chiara; Grimaldi, Vincenzo; Montesano, Maria Lourdes; Sommese, Linda; Schiano, Concetta; Napoli, Claudio

    2014-11-01

    Recently, management of patients awaiting solid organ transplantation has taken advantages after the development of more sensitive and accurate solid phase assays which have supported the historic complement dependent cytotoxicity. This approach has allowed the detection of antibodies in patients previously considered negative. The use of the single antigen beads resulted in a more accurate anti-human leukocyte antigen (HLA) antibody characterization. The detection of anti-HLA antibodies specific for C, DQ and DP loci that were not so well characterized has been possible through the implementation of the single antigen assay. The assessment of HLA compatibility has been expanded through the introduction of "epitope matching" concept and the definition of the unacceptable antigens for a more adequate evaluation of donor-recipient compatibility. However, the clinical impact of pre-formed and de novo anti-HLA antibodies detected by solid phase assays is still controversial due to the drawback related to result interpretation. Until today, the unresolved issues concern if all antibodies affect the medium and long term clinical outcome. An open debate on the clinical relevance of anti-HLA antibodies detected by single-antigen beads highlights needing to further investigations. Here, we describe the novel applications and the improvements of the solid-phase assay use. PMID:25171913

  13. Ganymede's Shadow

    NASA Technical Reports Server (NTRS)

    2007-01-01

    The New Horizons Long Range Reconnaissance Imager (LORRI) took this photo of Jupiter at 20:42:01 UTC on January 9, 2007, when the spacecraft was 80 million kilometers (49.6 million miles) from the giant planet. The volcanic moon Io is to the left of the planet; the shadow of the icy moon Ganymede moves across Jupiter's northern hemisphere.

    Ganymede's average orbit distance from Jupiter is about 1 million kilometers (620,000 miles); Io's is 422,000 kilometers (262,000 miles). Both Io and Ganymede are larger than Earth's moon; Ganymede is larger than the planet Mercury.

  14. Method and apparatus for shadow aperture backscatter radiography (SABR) system and protocol

    NASA Technical Reports Server (NTRS)

    Shedlock, Daniel (Inventor); Jacobs, Alan M. (Inventor); Jacobs, Sharon Auerback (Inventor); Dugan, Edward (Inventor)

    2010-01-01

    A shadow aperture backscatter radiography (SABR) system includes at least one penetrating radiation source for providing a penetrating radiation field, and at least one partially transmissive radiation detector, wherein the partially transmissive radiation detector is interposed between an object region to be interrogated and the radiation source. The partially transmissive radiation detector transmits a portion of the illumination radiation field. A shadow aperture having a plurality of radiation attenuating regions having apertures therebetween is disposed between the radiation source and the detector. The apertures provide illumination regions for the illumination radiation field to reach the object region, wherein backscattered radiation from the object is detected and generates an image by the detector in regions of the detector that are shadowed by the radiation attenuation regions.

  15. Deep shadow occulter

    NASA Technical Reports Server (NTRS)

    Cash, Webster (Inventor)

    2010-01-01

    Methods and apparatus are disclosed for occulting light. The occulter shape suppresses diffraction at any given size or angle and is practical to build because it can be made binary to avoid scatter. Binary structures may be fully opaque or fully transmitting at specific points. The diffraction suppression is spectrally broad so that it may be used with incoherent white light. An occulter may also include substantially opaque inner portion and an at least partially transparent outer portion. Such occulters may be used on the ground to create a deep shadow in a short distance, or may be used in space to suppress starlight and reveal exoplanets.

  16. The power of shadows - Shadow stereopsis

    NASA Technical Reports Server (NTRS)

    Puerta, Antonio Medina

    1989-01-01

    It is demonstrated that retinal images with no parallax disparity but with different shadows are fused stereoscopically, imparting depth perception to the imaged scene. Shadows are shown to be an important, hitherto undescribed, stereoscopic cue for depth perception.

  17. Elastomeric fluorescent POF for partial discharge detection: recent progress

    NASA Astrophysics Data System (ADS)

    Siebler, Daniel; Hohberg, Michaela; Rohwetter, Philipp; Brusenbach, Roy; Plath, Ronald

    2015-09-01

    We present recent progress in our development of fibre-optic sensors for the detection of partial discharge (PD) in silicone cable accessories, based on detecting related low-level optical emission. We experimentally show that the sensitive optical detection of PD can dramatically enhance the performance of conventional electrical PD measurement in electromagnetically noisy environments, and that it can yield high sensitivity and specificity even when no synchronous electrical PD measurement is conducted. This is demonstrated using a real-scale model of a high voltage cable accessory with a surface-attached conventional thermoplastic fluorescent polymer optical fibre (F-POF) sensor. In order to increase light collection efficiency, as a prerequisite for a commercially competitive implementation using cost-efficient detectors, sensing fibres will have to be integrated into the silicone rubber insulation, close to the potential origin of PD-induced damage. This is the rationale for our efforts to develop elastomeric fluorescent sensing fibres, tailored to the requirements of the application. We discuss specific challenges to be tackled and report on the successful implementation of all-silicone rubber fluorescent POF, to our best knowledge for the first time.

  18. Hygrometer for Detecting Water in Partially Enclosed Volumes

    NASA Technical Reports Server (NTRS)

    Youngquist, Robert C.; Surma, Jan; Parks, Steve

    2005-01-01

    A portable hygrometer has been devised to implement a pre-existing technique for detecting water trapped in partially enclosed volumes that may be difficult to reach and cannot be examined directly. The technique is based on the fact that eventually the air in such a volume becomes saturated or nearly so. The technique is straightforward: One measures the relative humidity and temperature of both the ambient air and a sample of air from the enclosed volume. If the relative humidity of the sample is significantly greater than that of the ambient air and/or if the sample is at or close to the dew point, then it can be concluded that water is trapped in the volume. Of course, the success of this technique depends on the existence of an access hole through which one can withdraw some air from the enclosed volume.

  19. Partially Nondestructive Continuous Detection of Individual Traveling Optical Photons

    NASA Astrophysics Data System (ADS)

    Hosseini, Mahdi; Beck, Kristin M.; Duan, Yiheng; Chen, Wenlan; Vuletić, Vladan

    2016-01-01

    We report the continuous and partially nondestructive measurement of optical photons. For a weak light pulse traveling through a slow-light optical medium (signal), the associated atomic-excitation component is detected by another light beam (probe) with the aid of an optical cavity. We observe strong correlations of gsp (2 )=4.4 (5 ) between the transmitted signal and probe photons. The observed (intrinsic) conditional nondestructive quantum efficiency ranges between 13% and 1% (65% and 5%) for a signal transmission range of 2% to 35%, at a typical time resolution of 2.5 μ s . The maximal observed (intrinsic) device nondestructive quantum efficiency, defined as the product of the conditional nondestructive quantum efficiency and the signal transmission, is 0.5% (2.4%). The normalized cross-correlation function violates the Cauchy-Schwarz inequality, confirming the nonclassical character of the correlations.

  20. Beamforming in an acoustic shadow

    NASA Technical Reports Server (NTRS)

    Havelock, David; Stinson, Michael; Daigle, Gilles

    1993-01-01

    The sound field deep within an acoustic shadow region is less well understood than that outside the shadow region. Signal levels are substantially lower within the shadow, but beamforming difficulties arise for other reasons such as loss of spatial coherence. Based on analysis of JAPE-91 data, and other data, three types of characteristic signals within acoustic shadow regions are identified. These signal types may correspond to different, intermittent signal propagation conditions. Detection and classification algorithms might take advantage of the signal characteristics. Frequency coherence is also discussed. The extent of coherence across frequencies is shown to be limited, causing difficulties for source classification based on harmonic amplitude relationships. Discussions emphasize short-term characteristics on the order of one second. A video presentation on frequency coherence shows the similarity, in the presence of atmospheric turbulence, between the received signal from a stable set of harmonics generated by a loudspeaker and that received from a helicopter hovering behind a hill.

  1. CRISPR Detection From Short Reads Using Partial Overlap Graphs.

    PubMed

    Ben-Bassat, Ilan; Chor, Benny

    2016-06-01

    Clustered regularly interspaced short palindromic repeats (CRISPR) are structured regions in bacterial and archaeal genomes, which are part of an adaptive immune system against phages. CRISPRs are important for many microbial studies and are playing an essential role in current gene editing techniques. As such, they attract substantial research interest. The exponential growth in the amount of bacterial sequence data in recent years enables the exploration of CRISPR loci in more and more species. Most of the automated tools that detect CRISPR loci rely on fully assembled genomes. However, many assemblers do not handle repetitive regions successfully. The first tool to work directly on raw sequence data is Crass, which requires reads that are long enough to contain two copies of the same repeat. We present a method to identify CRISPR repeats from raw sequence data of short reads. The algorithm is based on an observation differentiating CRISPR repeats from other types of repeats, and it involves a series of partial constructions of the overlap graph. This enables us to avoid many of the difficulties that assemblers face, as we merely aim to identify the repeats that belong to CRISPR loci. A preliminary implementation of the algorithm shows good results and detects CRISPR repeats in cases where other existing tools fail to do so. PMID:27058690

  2. Cloud shadow Speed Sensor (CSS)

    NASA Astrophysics Data System (ADS)

    Fung, Victor

    Changing cloud cover is a major source of solar radiation variability and poses challenges for the integration of solar energy. A compact and economical system that measures cloud shadow motion vectors to estimate power plant ramp rates and provide short-term forecasting is presented. The Cloud shadow Speed Sensor (CSS) is constructed using an array of luminance sensors and a high-speed data acquisition system to resolve the progression of cloud passages across the sensor footprint. An embedded microcontroller acquires the sensor data and uses a cross-correlation algorithm to determine cloud shadow motion vectors. The CSS was validated against an artificial shading test apparatus, an alternative method of cloud motion detection from ground-measured irradiance (linear cloud edge, LCE), and a UC San Diego sky imager (USI). The CSS detected artificial shadow directions and speeds to within 15° and 6 % accuracy, respectively. The CSS detected (real) cloud shadow directions and speeds with average weighted root-mean-square difference of 22° and 1.9 m s-1 when compared to USI and 33° and 1.5 m s -1 when compared to LCE results.

  3. Forming Spirals From Shadows

    NASA Astrophysics Data System (ADS)

    Kohler, Susanna

    2016-07-01

    What causes the large-scale spiral structures found in some protoplanetary disks? Most models assume theyre created by newly-forming planets, but a new study suggests that planets might have nothing to do with it.Perturbations from Planets?In some transition disks protoplanetary disks with gaps in their inner regions weve directly imaged large-scale spiral arms. Many theories currently attribute the formation of these structures to young planets: either the direct perturbations of a planet embedded in the disk cause the spirals, or theyre indirectly caused by the orbit of a planetary body outside of the arms.Another example of spiral arms detected in a protoplanetary disk, MWC 758. [NASA/ESA/ESO/M. Benisty et al.]But what if you could get spirals without any planets? A team of scientists led by Matas Montesinos (University of Chile) have recently published a study in which they examine what happens to a shadowed protoplanetary disk.Casting Shadows with WarpsIn the teams setup, they envision a protoplanetary disk that is warped: the inner region is slightly tilted relative to the outer region. As the central star casts light out over its protoplanetary disk, this disk warping would cause some regions of the disk to be shaded in a way that isnt axially symmetric with potentially interesting implications.Montesinos and collaborators ran 2D hydrodynamics simulations to determine what happens to the motion of particles within the disk when they pass in and out of the shadowed regions. Since the shadowed regions are significantly colder than the illuminated disk, the pressure in these regions is much lower. Particles are therefore accelerated and decelerated as they pass through these regions, and the lack of axial symmetry causes spiral density waves to form in the disk as a result.Initial profile for the stellar heating rate per unit area for one of the authors simulations. The regions shadowed as a result of the disk warp subtend 0.5 radians each (shown on the left

  4. Interactive removal and ground truth for difficult shadow scenes.

    PubMed

    Gong, Han; Cosker, Darren

    2016-09-01

    A user-centric method for fast, interactive, robust, and high-quality shadow removal is presented. Our algorithm can perform detection and removal in a range of difficult cases, such as highly textured and colored shadows. To perform detection, an on-the-fly learning approach is adopted guided by two rough user inputs for the pixels of the shadow and the lit area. After detection, shadow removal is performed by registering the penumbra to a normalized frame, which allows us efficient estimation of nonuniform shadow illumination changes, resulting in accurate and robust removal. Another major contribution of this work is the first validated and multiscene category ground truth for shadow removal algorithms. This data set containing 186 images eliminates inconsistencies between shadow and shadow-free images and provides a range of different shadow types such as soft, textured, colored, and broken shadow. Using this data, the most thorough comparison of state-of-the-art shadow removal methods to date is performed, showing our proposed algorithm to outperform the state of the art across several measures and shadow categories. To complement our data set, an online shadow removal benchmark website is also presented to encourage future open comparisons in this challenging field of research. PMID:27607503

  5. 2017 Eclipse Shadow Cones

    NASA Video Gallery

    A solar eclipse occurs when the Moon's shadow falls on the Earth. The shadow comprises two concentric cones called the umbra and the penumbra. Within the smaller, central umbra, the Sun is complete...

  6. Change blindness for cast shadows in natural scenes: Even informative shadow changes are missed.

    PubMed

    Ehinger, Krista A; Allen, Kala; Wolfe, Jeremy M

    2016-05-01

    Previous work has shown that human observers discount or neglect cast shadows in natural and artificial scenes across a range of visual tasks. This is a reasonable strategy for a visual system designed to recognize objects under a range of lighting conditions, since cast shadows are not intrinsic properties of the scene-they look different (or disappear entirely) under different lighting conditions. However, cast shadows can convey useful information about the three-dimensional shapes of objects and their spatial relations. In this study, we investigated how well people detect changes to cast shadows, presented in natural scenes in a change blindness paradigm, and whether shadow changes that imply the movement or disappearance of an object are more easily noticed than shadow changes that imply a change in lighting. In Experiment 1, a critical object's shadow was removed, rotated to another direction, or shifted down to suggest that the object was floating. All of these shadow changes were noticed less often than changes to physical objects or surfaces in the scene, and there was no difference in the detection rates for the three types of changes. In Experiment 2, the shadows of visible or occluded objects were removed from the scenes. Although removing the cast shadow of an occluded object could be seen as an object deletion, both types of shadow changes were noticed less often than deletions of the visible, physical objects in the scene. These results show that even informative shadow changes are missed, suggesting that cast shadows are discounted fairly early in the processing of natural scenes. PMID:26846753

  7. ROSAT detection of an X-ray shadow in the 1/4-keV diffuse background in the Draco nebula

    NASA Technical Reports Server (NTRS)

    Snowden, S. L.; Mebold, U.; Hirth, W.; Herbstmeier, U.; Schmitt, J. H. M.

    1991-01-01

    The detection by the Roentgen satellite (ROSAT) X-ray telescope of a shadow in the 1/4-keV (C-band, 0.1 to 0.284 keV) cosmic diffuse background is reported. The location and morphology of the local minimum in X-rays are in clear agreement with a discrete H I cloud. The shadow is very deep with a minimum level at 50 percent of the surrounding emission; therefore, a minimum of 50 percent of the observed off-cloud flux must originate on the far side of the cloud. The analysis of H I velocity components links the cloud with the Draco nebula (distance of about 600 parsecs); it then follows that there is significant 1/4-keV X-ray emission at large distance (more than 400 parsecs) from the galactic plane along this line of sight. The extent of the distant emission region is uncertain, and if it indicates the existence of a hot galactic corona, it must be patchy in nature.

  8. Bringing Light onto Shadows

    ERIC Educational Resources Information Center

    Barrow, Lloyd H.

    2007-01-01

    "What starts out long but gets shorter then longer each day?" Shadows! This student's clever riddle was an opportunity to investigate how the Sun's daily position in the sky influences shadow length. Thus began a mini-lesson which was created to help third-grade students understand that a shadow occurs when an opaque object blocks light (Shapiro…

  9. Testing the stress shadow hypothesis

    NASA Astrophysics Data System (ADS)

    Felzer, Karen R.; Brodsky, Emily E.

    2005-05-01

    A fundamental question in earthquake physics is whether aftershocks are predominantly triggered by static stress changes (permanent stress changes associated with fault displacement) or dynamic stresses (temporary stress changes associated with earthquake shaking). Both classes of models provide plausible explanations for earthquake triggering of aftershocks, but only the static stress model predicts stress shadows, or regions in which activity is decreased by a nearby earthquake. To test for whether a main shock has produced a stress shadow, we calculate time ratios, defined as the ratio of the time between the main shock and the first earthquake to follow it and the time between the last earthquake to precede the main shock and the first earthquake to follow it. A single value of the time ratio is calculated for each 10 × 10 km bin within 1.5 fault lengths of the main shock epicenter. Large values of the time ratio indicate a long wait for the first earthquake to follow the main shock and thus a potential stress shadow, whereas small values indicate the presence of aftershocks. Simulations indicate that the time ratio test should have sufficient sensitivity to detect stress shadows if they are produced in accordance with the rate and state friction model. We evaluate the 1989 MW 7.0 Loma Prieta, 1992 MW 7.3 Landers, 1994 MW 6.7 Northridge, and 1999 MW 7.1 Hector Mine main shocks. For each main shock, there is a pronounced concentration of small time ratios, indicating the presence of aftershocks, but the number of large time ratios is less than at other times in the catalog. This suggests that stress shadows are not present. By comparing our results to simulations we estimate that we can be at least 98% confident that the Loma Prieta and Landers main shocks did not produce stress shadows and 91% and 84% confident that stress shadows were not generated by the Hector Mine and Northridge main shocks, respectively. We also investigate the long hypothesized existence

  10. Detecting and correcting partial errors: Evidence for efficient control without conscious access.

    PubMed

    Rochet, N; Spieser, L; Casini, L; Hasbroucq, T; Burle, B

    2014-09-01

    Appropriate reactions to erroneous actions are essential to keeping behavior adaptive. Erring, however, is not an all-or-none process: electromyographic (EMG) recordings of the responding muscles have revealed that covert incorrect response activations (termed "partial errors") occur on a proportion of overtly correct trials. The occurrence of such "partial errors" shows that incorrect response activations could be corrected online, before turning into overt errors. In the present study, we showed that, unlike overt errors, such "partial errors" are poorly consciously detected by participants, who could report only one third of their partial errors. Two parameters of the partial errors were found to predict detection: the surface of the incorrect EMG burst (larger for detected) and the correction time (between the incorrect and correct EMG onsets; longer for detected). These two parameters provided independent information. The correct(ive) responses associated with detected partial errors were larger than the "pure-correct" ones, and this increase was likely a consequence, rather than a cause, of the detection. The respective impacts of the two parameters predicting detection (incorrect surface and correction time), along with the underlying physiological processes subtending partial-error detection, are discussed. PMID:24347086

  11. Shadow of a naked singularity

    NASA Astrophysics Data System (ADS)

    Ortiz, Néstor; Sarbach, Olivier; Zannias, Thomas

    2015-08-01

    We analyze the redshift suffered by photons originating from an external source, traversing a collapsing dust cloud, and finally being received by an asymptotic observer. In addition, we study the shadow that the collapsing cloud casts on the sky of the asymptotic observer. We find that the resulting redshift and properties of the shadow depend crucially on whether the final outcome of the complete gravitational collapse is a black hole or a naked singularity. In the black hole case, the shadow is due to the high redshift acquired by the photons as they approach the event horizon, implying that their energy is gradually redshifted toward zero within a few crossing times associated with the event horizon radius. In contrast to this, a naked singularity not only absorbs photons originating from the source, but it also emits infinitely redshifted photons with and without angular momenta. This emission introduces an abrupt cutoff in the frequency shift of the photons detected in directions close to the radial one, and it is responsible for the shadow masking the source in the naked singularity case. Furthermore, even though the shadow forms and begins to grow immediately after the observer crosses the Cauchy horizon, it takes many more crossing times than in the black hole case for the source to be occulted from the observer's eyes. We discuss possible implications of our results for testing the weak cosmic censorship hypothesis. Even though at late times the image of the source perceived by the observer looks the same in both cases, the dynamical formation of the shadow and the redshift images has distinct features and time scales in the black hole versus the naked singularity case. For stellar collapse, these time scales seem to be too short to be resolved with existing technology. However, our results may be relevant for the collapse of seeds leading to supermassive black holes.

  12. Cosmic ray sun shadow in Soudan 2 underground muon flux.

    SciTech Connect

    Allison, W. W. M.; Alner, G. J.; Ayres, D. S.; Barrett, W. L.; Bode, C.; Fields, T. H.; Goodman, M. C.; Joffe-Minor, T.; Price, L. E.; Seidlein, R.; Soudan 2 Collaboration; Thron, J. L.

    1999-06-23

    The absorption of cosmic rays by the sun produces a shadow at the earth. The angular offset and broadening of the shadow are determined by the magnitude and structure of the interplanetary magnetic field (IPMF) in the inner solar system. The authors report the first measurement of the solar cosmic ray shadow by detection of deep underground muon flux in observations made during the entire ten-year interval 1989 to 1998. The sun shadow varies significantly during this time, with a 3.3{sigma} shadow observed during the years 1995 to 1998.

  13. Gas and Shadow Swing

    NASA Astrophysics Data System (ADS)

    Tsai, Chi-Hung; Lai, Mei-Yi; Liu, Che-Wei; Huang, Shiang-Yin; Lin, Che-Yu; Yeh, Jeng-Sheng

    In our digital art, we design a folding fan as an interactive magic device. You can use it to play with gas around the world of illusions. Although gas could not be seen in our real world, we still want to interact with it in our illusions by the element of bubble shadows. Opening and swinging the folding fan can blow the bubble shadows away; closing and swinging it can break bubbles. If the magic fan touches the shadow of gas, the bubble shadows will explode and release colorful particles to surround you. Those actions are controlled and located by our circuits with Arduino board.

  14. [Partially automated antigen determination and antibody detection with microtiter plates].

    PubMed

    Rapp, C; Weisshaar, C

    1993-01-01

    In addition to several conventional methods for the detection of red cell antigens, the use of microplates has various advantages either as a solid-phase assay (enzyme immunoassay) or as native microplate. Microplates may also be used for the detection of red cell antibodies in 'pooled-cell solid-phase assays' of the second generation and for antibody screening. Blood donors and patients are the two main fields which are to be examined in immunohematology. There are various advantages in using the microplate in blood group serology: (i) if there is hardware already available, like sample processors and microplate readers, the use of microplates in blood group serology reduces the costs even if the equipment has to be purchased for this purpose only; (ii) low quantities of reagents are used in microplate assays; (iii) the application of bar codes on tubes and microplates guarantees the most security in sample identification; (iv) it is possible to investigate blood samples selectively depending on the available software if antibody detection is done as the sixth test beside anti-HIV, anti-HCV, HBsAG, lues antibodies and ALT, and (v) recording of data will be easy if electronic data processing is used. PMID:7693246

  15. A Shadowing Problem in the Detection of Overlapping Communities: Lifting the Resolution Limit through a Cascading Procedure

    PubMed Central

    Young, Jean-Gabriel; Allard, Antoine; Hébert-Dufresne, Laurent; Dubé, Louis J.

    2015-01-01

    Community detection is the process of assigning nodes and links in significant communities (e.g. clusters, function modules) and its development has led to a better understanding of complex networks. When applied to sizable networks, we argue that most detection algorithms correctly identify prominent communities, but fail to do so across multiple scales. As a result, a significant fraction of the network is left uncharted. We show that this problem stems from larger or denser communities overshadowing smaller or sparser ones, and that this effect accounts for most of the undetected communities and unassigned links. We propose a generic cascading approach to community detection that circumvents the problem. Using real and artificial network datasets with three widely used community detection algorithms, we show how a simple cascading procedure allows for the detection of the missing communities. This work highlights a new detection limit of community structure, and we hope that our approach can inspire better community detection algorithms. PMID:26461919

  16. Shadows That Enlighten

    ERIC Educational Resources Information Center

    Vincent, Dan; Cassel, Darlinda

    2011-01-01

    This inquiry-based investigation focused on shadow measurement and the apparent movement of the Sun throughout the school year. Students would collect data about their shadows weekly. Toward the end of the year, students would then organize and interpret their data. The authors hoped they would discover that the angle of the Sun changes throughout…

  17. Rao and Wald Tests for Adaptive Detection in Partially Homogeneous Environment with a Diversely Polarized Antenna

    PubMed Central

    Zhang, Chaozhu; Zhang, Jing; Liu, Chengyuan

    2013-01-01

    This study considers Rao test and Wald test for adaptive detection based on a diversely polarized antenna (DPA) in partially homogeneous environment. The theoretical expressions for the probability of false alarm and detection are derived, and constant false alarm rate (CFAR) behaviour is remarked on. Furthermore, the monotonicities of detection probability of the two detectors are proved, and a polarization optimization detection algorithm to enhance the detection performance is proposed. The numerical simulations are conducted to attest to the validity of the above theoretical analysis and illustrate the improvement in the detection performance of the proposed optimization algorithm. PMID:24174914

  18. NATURE OF THE DRY SHADOW BELOW CAVITIES IN VADOSE ZONE

    SciTech Connect

    T.A. Ghezzehei; T.J. Kneafsey; G.W. Su

    2005-09-07

    Several theoretical studies have indicated that the presence of subsurface cavities in the vadose zone results in complete or partial diversion of flow around cavities. As a result, the region immediately below the cavities is partially shielded from the downward flux. This shadowing effect of cavities can be exploited in the design of dry subsurface storage facilities as an additional barrier to contain waste within or around the cavities. However, empirical evidence that supports these theories is lacking. This study is motivated by the inherent difficulty to make direct observation of the shadow zone as it occurs under very dry conditions. To aid future field and laboratory scale investigations of the shadow zone, we performed rigorous theoretical scrutiny of the conditions that result in the shadowing effect. We formulated relative permeability and saturation based criteria to identify the boundaries of the shadow zone. Analytical and numerical tools were used to develop dimensionless scaling laws that define the size of the shadow zone. Moreover, we analyzed the effect of natural perturbations (heterogeneity and fracturing) on the integrity of the shadow zone. The results will be used in selecting study sites; identifying observation locations and methods; and designing active tests to test the concept of shadow zone.

  19. Detecting Random, Partially Random, and Nonrandom Minnesota Multiphasic Personality Inventory--Adolescent Protocols

    ERIC Educational Resources Information Center

    Pinsoneault, Terry B.

    2005-01-01

    The ability of the Minnesota Multiphasic Personality Inventory-Adolescent (MMPI-A; J. N. Butcher et al., 1992) validity scales to detect random, partially random, and nonrandom MMPI-A protocols was investigated. Investigations included the Variable Response Inconsistency scale (VRIN), F, several potentially useful new F and VRIN subscales, and…

  20. Detecting Random, Partially Random, and Nonrandom Minnesota Multiphasic Personality Inventory-2 Protocols

    ERIC Educational Resources Information Center

    Pinsoneault, Terry B.

    2007-01-01

    The ability of the Minnesota Multiphasic Personality Inventory-2 (MMPI-2; J. N. Butcher et al., 2001) validity scales to detect random, partially random, and nonrandom MMPI-2 protocols was investigated. Investigations included the Variable Response Inconsistency scale (VRIN), F, several potentially useful new F and VRIN subscales, and F-sub(b) - F…

  1. Detecting and Analyzing Differential Item Functioning in an Essay Test Using the Partial Credit Model.

    ERIC Educational Resources Information Center

    Ferrara, Steven; Walker-Bartnick, Leslie

    A procedure was developed to detect differential item functioning (DIF) in a standardized essay test using the Partial Credit Model, the general polychotomous form of the Rasch model. Using a panel of experts in the writing process, hypothesized explanations for DIF at some score points were developed. Data for the study included averaged…

  2. Review on partial discharge detection techniques related to high voltage power equipment using different sensors

    NASA Astrophysics Data System (ADS)

    Yaacob, M. M.; Alsaedi, M. A.; Rashed, J. R.; Dakhil, A. M.; Atyah, S. F.

    2014-12-01

    When operating an equipment or a power system at the high voltage, problems associated with partial discharge (PD) can be tracked down to electromagnetic emission, acoustic emission or chemical reactions such as the formation of ozone and nitrous oxide gases. The high voltage equipment and high voltage installation owners have come to terms with the need for conditions monitoring the process of PD in the equipments such as power transformers, gas insulated substations (GIS), and cable installations. This paper reviews the available PD detection methods (involving high voltage equipment) such as electrical detection, chemical detection, acoustic detection, and optical detection. Advantages and disadvantages of each method have been explored and compared. The review suggests that optical detection techniques provide many advantages in the consideration of accuracy and suitability for the applications when compared to other techniques.

  3. Review on partial discharge detection techniques related to high voltage power equipment using different sensors

    NASA Astrophysics Data System (ADS)

    Yaacob, M. M.; Alsaedi, M. A.; Rashed, J. R.; Dakhil, A. M.; Atyah, S. F.

    2014-09-01

    When operating an equipment or a power system at the high voltage, problems associated with partial discharge (PD) can be tracked down to electromagnetic emission, acoustic emission or chemical reactions such as the formation of ozone and nitrous oxide gases. The high voltage equipment and high voltage installation owners have come to terms with the need for conditions monitoring the process of PD in the equipments such as power transformers, gas insulated substations (GIS), and cable installations. This paper reviews the available PD detection methods (involving high voltage equipment) such as electrical detection, chemical detection, acoustic detection, and optical detection. Advantages and disadvantages of each method have been explored and compared. The review suggests that optical detection techniques provide many advantages in the consideration of accuracy and suitability for the applications when compared to other techniques.

  4. Wave shadowing and modulation of microwave backscatter from the ocean

    NASA Astrophysics Data System (ADS)

    Plant, William J.; Farquharson, Gordon

    Shadowing and modulation of microwave backscatter by ocean waves are studied using coherent X-band radars. Two types of shadowing are investigated: geometric shadowing (complete blockage of incident rays) and partial shadowing (polarization-dependent diffraction combined with weak scatterers). We point out that the frequency of occurrence of zero signal-to-noise ratio samples cannot depend on the incident power level or the polarization if geometric shadowing occurs but can if partial shadowing exists. We then compare this behavior with observations, and show that the data do not support the hypothesis that geometric shadowing plays a significant role in low-grazing-angle microwave scattering from the ocean surface. Furthermore, our data indicate that partial shadowing only depends significantly on polarization for the steep waves found near shorelines. We also study the modulation of microwave backscatter by ocean waves using these data by looking at the phase differences between received power and scatterer velocity. These phase differences appear to be rather well explained by standard composite surface theory at VV polarization, having values that are positive looking up wave and negative looking down wave. For HH polarization, however, breaking effects come into play and overshadow composite surface effects of free waves. They cause the phase difference to be near zero for up wave looks and near 180° for down-wave looks. A simple model that involves both breaking and freely propagating waves but does not include any shadowing effects is shown to account for observed phase differences at both polarizations to within about 10°.

  5. [Partial least squares regression variable screening studies on apple soluble solids NIR spectral detection].

    PubMed

    Ouyang, Ai-Guo; Xie, Xiao-Qiang; Zhou, Yan-Rui; Liu, Yan-De

    2012-10-01

    Abstract To improve the predictive ability and robustness of the NIR correction model of the soluble solid content (SSC) of apple, the reverse interval partial least squares method, genetic algorithm and the continuous projection method were implemented to select variables of the NIR spectroscopy of the soluble solid content (SSC) of apple, and the partial least squares regression model was established. By genetic algorithm for screening of the 141 variables of the correction model, prediction has the best effect. And compared to the full spectrum correction model, the correlation coefficient increased to 0.96 from 0.93, forecast root mean square error decreased from 0.30 degrees Brix to 0.23 degrees Brix. This experimental results show that the genetic algorithm combined with partial least squares regression method improved the detection precision of the NIR model of the soluble solid content (SSC) of apple. PMID:23285864

  6. Detection of partial-thickness tears in ligaments and tendons by Stokes-polarimetry imaging

    NASA Astrophysics Data System (ADS)

    Kim, Jihoon; John, Raheel; Walsh, Joseph T.

    2008-02-01

    A Stokes polarimetry imaging (SPI) system utilizes an algorithm developed to construct degree of polarization (DoP) image maps from linearly polarized light illumination. Partial-thickness tears of turkey tendons were imaged by the SPI system in order to examine the feasibility of the system to detect partial-thickness rotator cuff tear or general tendon pathology. The rotating incident polarization angle (IPA) for the linearly polarized light provides a way to analyze different tissue types which may be sensitive to IPA variations. Degree of linear polarization (DoLP) images revealed collagen fiber structure, related to partial-thickness tears, better than standard intensity images. DoLP images also revealed structural changes in tears that are related to the tendon load. DoLP images with red-wavelength-filtered incident light may show tears and related organization of collagen fiber structure at a greater depth from the tendon surface. Degree of circular polarization (DoCP) images exhibited well the horizontal fiber orientation that is not parallel to the vertically aligned collagen fibers of the tendon. The SPI system's DOLP images reveal alterations in tendons and ligaments, which have a tissue matrix consisting largely of collagen, better than intensity images. All polarized images showed modulated intensity as the IPA was varied. The optimal detection of the partial-thickness tendon tears at a certain IPA was observed. The SPI system with varying IPA and spectral information can improve the detection of partial-thickness rotator cuff tears by higher visibility of fiber orientations and thereby improve diagnosis and treatment of tendon related injuries.

  7. The performance of heterodyne detection system for partially coherent beams in turbulent atmosphere

    NASA Astrophysics Data System (ADS)

    Chengqiang, Li; Tingfeng, Wang; Heyong, Zhang; Jingjiang, Xie; Lisheng, Liu; Shuai, Zhao; Jin, Guo

    2015-12-01

    The performance of heterodyne system is discussed for partially coherent beams in turbulent atmosphere by introducing turbulence spectrum of refractive-index fluctuations. Several analytic formulae for the heterodyne detection system using the partially coherent Gaussian Schell-model beam are presented. Based on Tatarskii spectrum model, some numerical results are given for the variation in the heterodyne efficiency with the misalignment angle, detector diameter, turbulence conditions, and parameters of the overlapping beams. According to the numerical results, we find that the turbulent atmosphere degrades the heterodyne efficiency significantly, and the variation in heterodyne efficiency is even slower against the misalignment angle in turbulence. For the deterministic received signal and the detector, the performance of the heterodyne detection can be adjusted by controlling the local oscillator signal parameters.

  8. Shadows, An Environmental Investigation.

    ERIC Educational Resources Information Center

    National Wildlife Federation, Washington, DC.

    This environmental unit is one of a series designed for integration within an existing curriculum. The units are self-contained and require minimal teacher preparation. The philosophy behind the units is based on an experience-oriented process that encourages self-paced independent work. This unit on shadows is designed for all elementary levels,…

  9. The Shadow Curriculum

    ERIC Educational Resources Information Center

    Brown, Pamela U.

    2005-01-01

    This chapter will explore the "shadow curriculum" (a term used by those who question the assumption that direct selling to students who are compelled to attend school is questionable on several levels--ethical, moral, and democratic) and its connection to media literacy. The author first summarizes the kinds of marketing in schools that have…

  10. Observe Your Shadow

    ERIC Educational Resources Information Center

    Rovšek, Barbara

    2016-01-01

    Observe Your Shadow was the title of an observational experiment that was, among others, conducted in the scope of the past year's (2014-2015) first Slovene science competition for elementary school pupils between the ages of 6 and 13. The main reason for establishing a new science competition was popularization of science and its experimental…

  11. Chasing the Moon's Shadow.

    ERIC Educational Resources Information Center

    Bell, Trudy E.

    1991-01-01

    Suggestions and tips for novice and experienced eclipse watchers are provided. Discussed are the mysterious shadow bands that occur just minutes before an eclipse. Directions for building a deluxe pinhole projector for observing the eclipse, a reading list, and a glossary of related terms are included. (KR)

  12. Occlusion, optimization, emergency response and partial falls in a senior collapse detection system

    NASA Astrophysics Data System (ADS)

    Grewe, Lynne; Magaña-Zook, Steven

    2015-05-01

    Vision based fall detection systems must often contend with more issues than the need to simply identify true fall cases. All vision systems have areas of the frame they cannot see, occlusion, and this becomes of critical importance for systems monitoring for falls. Even with full scene visibility, human falls have an incredible variety requiring special detectors for edge cases like partial falls. Each detection algorithm is only as good as the parameters it is provided and so optimum values for each detector are found using Particle Swarm Optimization. We then discuss the use of email and short message service (SMS) in alerting caregivers that a fall has occurred.

  13. Enhanced localized plasmonic detections using partially-embedded gold nanoparticles and ellipsometric measurements

    PubMed Central

    Moirangthem, Rakesh Singh; Yaseen, Mohammad Tariq; Wei, Pei-Kuen; Cheng, Ji-Yen; Chang, Yia-Chung

    2012-01-01

    A cost-effective, stable and ultrasensitive localized surface plasmon resonance (LSPR) sensor based on gold nanoparticles (AuNPs) partially embedded in transparent substrate is presented. Partially embedded AuNPs were prepared by thermal annealing of gold thin films deposited on glass at a temperature close to the glass transition temperature of the substrate. Annealed samples were optically characterized by using spectroscopic ellipsometry and compare with theoretical modeling to understand the optical responses from the samples. By combining the partially-embedded AuNPs substrate with a microfluidic flow cell and dove prism in an ellipsometry setup, an ultrasensitive change in the LSPR signal can be detected. The refractive index sensitivity obtained from the phase measurement is up to 1938 degrees/RIU which is several times higher than that of synthesized colloidal gold nanoparticles. The sample is further used to investigate the interactions between primary and secondary antibodies. The bio-molecular detection limit of the LSPR signal is down to 20 pM. Our proposed sensor is label free, non-destructive, with high sensitivity, low cost, and easy to fabricate. These features make it feasible for commercialization in biomedical applications. PMID:22567583

  14. A general variational framework considering cast shadows for the topographic correction of remote sensing imagery

    NASA Astrophysics Data System (ADS)

    Li, Huifang; Xu, Liming; Shen, Huanfeng; Zhang, Liangpei

    2016-07-01

    Topographic shadows are inevitable obstacles for the interpretation of remote sensing images covering rugged terrain. A general variational topographic correction (TC) framework is proposed in this paper by considering not only self shadows but also cast shadows. Cast shadows are first detected by integrating the radiometric and topographic features of the observed region. The cosine values of the incidence angles for the cast shadows are then corrected by the variational framework. The corrected incidence angles can be used in any traditional TC model to compensate for the shadows in mountainous regions. The proposed variational framework was utilized in eight different traditional TC models, and the results were compared with the traditional results. Images from two different regions were employed to test the framework. The results suggest that the proposed framework can raise the accuracy of shadow correction by both subjective and objective evaluations, owing to the correction of the cast shadows.

  15. My shadow, myself: cast-body shadows are embodied.

    PubMed

    Kuylen, Christopher; Balas, Benjamin; Thomas, Laura E

    2014-06-01

    Objects that serve as extensions of the body can produce a sensation of embodiment, feeling as if they are a part of us. We investigated the characteristics that drive an object's embodiment, examining whether cast-body shadows, a purely visual stimulus, are embodied. Tools are represented as an extension of the body when they enable observers to interact with distant targets, perceptually distorting space. We examined whether perceptual distortion would also result from exposure to cast-body shadows in two separate distance estimation perceptual matching tasks. If observers represent cast-body shadows as extensions of their bodies, then when these shadows extend toward a target, it should appear closer than when no shadow is present (Experiment 1). This effect should not occur when a non-cast-body shadow is cast toward a target (Experiment 2). We found perceptual distortions in both cast-body shadow and tool-use conditions, but not in our non-cast-body shadow condition. These results suggest that, although cast-body shadows do not enable interaction with objects or provide direct tactile feedback, observers nonetheless represent their shadows as if they were a part of them. PMID:24243137

  16. Inflation and shadow matter

    NASA Technical Reports Server (NTRS)

    Krauss, L. M.; Guth, A. H.; Spergel, D. N.; Field, G. B.; Press, W. H.

    1986-01-01

    The possible production of shadow matter during the period of cosmic inflation is considered. The superstring theory of Gross et al. (1985), which results in a gauge group E8 x E8, could, at low energies, result in the existence of two sectors: an observed sector associated with all familiar particles and interactions, and a hidden one whose particles couple only through gravitational interactions with ordinary matter. It is demonstrated here that if, in the early universe, an inflationary phase is associated with the breaking of one of the symmetries in the E8 x E8 theory, this strongly constrains the physics of both sectors if shadow matter is to be the missing mass in the universe.

  17. Observe Your Shadow

    NASA Astrophysics Data System (ADS)

    Rovšek, Barbara

    2016-04-01

    Observe Your Shadow was the title of an observational experiment that was, among others, conducted in the scope of the past year's (2014-2015) first Slovene science competition for elementary school pupils between the ages of 6 and 13. The main reason for establishing a new science competition was popularization of science and its experimental methods, particularly among elementary school students. Elementary school teachers are not generally specialists in science, but rather have (and should have) extremely wide scopes of interests and competencies. By providing them with ideas and instructions for science experiments, we aim to enrich regular school lessons. In the first year alone, the competition took place in over half of Slovene elementary schools, with a total of 9000 participating students. In this paper we shall report about pupils' responses to tasks related to one of the experiments, namely, observation of their shadows on a sunny day.

  18. Using gradient-based ray and candidate shadow maps for environmental illumination distribution estimation

    NASA Astrophysics Data System (ADS)

    Eem, Changkyoung; Kim, Iksu; Hong, Hyunki

    2015-07-01

    A method to estimate the environmental illumination distribution of a scene with gradient-based ray and candidate shadow maps is presented. In the shadow segmentation stage, we apply a Canny edge detector to the shadowed image by using a three-dimensional (3-D) augmented reality (AR) marker of a known size and shape. Then the hierarchical tree of the connected edge components representing the topological relation is constructed, and the connected components are merged, taking their hierarchical structures into consideration. A gradient-based ray that is perpendicular to the gradient of the edge pixel in the shadow image can be used to extract the shadow regions. In the light source detection stage, shadow regions with both a 3-D AR marker and the light sources are partitioned into candidate shadow maps. A simple logic operation between each candidate shadow map and the segmented shadow is used to efficiently compute the area ratio between them. The proposed method successively extracts the main light sources according to their relative contributions on the segmented shadows. The proposed method can reduce unwanted effects due to the sampling positions in the shadow region and the threshold values in the shadow edge detection.

  19. Rain-Induced Shadows

    ERIC Educational Resources Information Center

    Bartlett, Albert A.

    2006-01-01

    Several times a week I walk by a metal chair that is fastened to a flat concrete slab at an outdoor bus stop here in Boulder. One day I noticed on the concrete a nice shadow image of the woven metal seat of the chair (Fig. 1). The seat and back of the chair are formed from 3.8-cm wide strips of metal spaced 3.8 cm apart. The seat is about 39 cm…

  20. Spirit Spies Its Shadow

    NASA Technical Reports Server (NTRS)

    2004-01-01

    This 360-degree panorama taken by the navigation camera on the Mars Exploration Rover Spirit highlights the bumpy terrain surrounding the rover. Spirit's shadow can be seen in a small hollow lying between the rover and its intended target, the eastern-lying 'Columbia Hills.' Spirit's longest drive so far covered about 88.5 meters (about 290 feet) and took place on sol 113. This image was taken on sol 112 (April 26, 2004).

  1. Titan Casts Revealing Shadow

    NASA Astrophysics Data System (ADS)

    2004-05-01

    A rare celestial event was captured by NASA's Chandra X-ray Observatory as Titan -- Saturn's largest moon and the only moon in the Solar System with a thick atmosphere -- crossed in front of the X-ray bright Crab Nebula. The X-ray shadow cast by Titan allowed astronomers to make the first X-ray measurement of the extent of its atmosphere. On January 5, 2003, Titan transited the Crab Nebula, the remnant of a supernova explosion that was observed to occur in the year 1054. Although Saturn and Titan pass within a few degrees of the Crab Nebula every 30 years, they rarely pass directly in front of it. "This may have been the first transit of the Crab Nebula by Titan since the birth of the Crab Nebula," said Koji Mori of Pennsylvania State University in University Park, and lead author on an Astrophysical Journal paper describing these results. "The next similar conjunction will take place in the year 2267, so this was truly a once in a lifetime event." Animation of Titan's Shadow on Crab Nebula Animation of Titan's Shadow on Crab Nebula Chandra's observation revealed that the diameter of the X-ray shadow cast by Titan was larger than the diameter of its solid surface. The difference in diameters gives a measurement of about 550 miles (880 kilometers) for the height of the X-ray absorbing region of Titan's atmosphere. The extent of the upper atmosphere is consistent with, or slightly (10-15%) larger, than that implied by Voyager I observations made at radio, infrared, and ultraviolet wavelengths in 1980. "Saturn was about 5% closer to the Sun in 2003, so increased solar heating of Titan may account for some of this atmospheric expansion," said Hiroshi Tsunemi of Osaka University in Japan, one of the coauthors on the paper. The X-ray brightness and extent of the Crab Nebula made it possible to study the tiny X-ray shadow cast by Titan during its transit. By using Chandra to precisely track Titan's position, astronomers were able to measure a shadow one arcsecond in

  2. Single- and multiple-pulse noncoherent detection statistics associated with partially developed speckle.

    PubMed

    Osche, G R

    2000-08-20

    Single- and multiple-pulse detection statistics are presented for aperture-averaged direct detection optical receivers operating against partially developed speckle fields. A partially developed speckle field arises when the probability density function of the received intensity does not follow negative exponential statistics. The case of interest here is the target surface that exhibits diffuse as well as specular components in the scattered radiation. An approximate expression is derived for the integrated intensity at the aperture, which leads to single- and multiple-pulse discrete probability density functions for the case of a Poisson signal in Poisson noise with an additive coherent component. In the absence of noise, the single-pulse discrete density function is shown to reduce to a generalized negative binomial distribution. The radar concept of integration loss is discussed in the context of direct detection optical systems where it is shown that, given an appropriate set of system parameters, multiple-pulse processing can be more efficient than single-pulse processing over a finite range of the integration parameter n. PMID:18350006

  3. Shadows and silhouettes in computer vision

    SciTech Connect

    Shafer, S.A.

    1985-01-01

    This book explains how shadows can be analyzed to determine three-dimensional surface orientation. These topics and techniques covered have applications in aerial photo-interpretation, robot vision and range-finder data analysis. Topics considered include imaging geometry and the gradient space, the basic shadow problem, variations in lighting, shadows falling on polyhedra, shadows cast by polyhedra, shadow geometry for curved surfaces, generalized cylinders, contour analysis for SHGs, shadow geometry for solids of revolution, shadow geometry, and other techniques.

  4. Partial discharge early-warning through ultraviolet spectroscopic detection of SO2

    NASA Astrophysics Data System (ADS)

    Zhao, Yu; Wang, Xianpei; Dai, Dangdang; Dong, Zhengcheng; Huang, Yunguang

    2014-03-01

    Surveillance of SF6 decomposition products is significant for detection of partial discharge (PD) in gas insulation switchgear (GIS). As a basis in on-site detection and diagnosis, PD early-warning aims to quickly find the abnormalities using a simple and cheap device. In this paper, SO2 is chosen as a feature product and detected through ultraviolet spectroscopy. The derivative method is employed for baseline correction and spectral enhancement. The standard gases of the main decomposition products are qualitatively and quantitatively detected. Then decomposition experiments with different defects are designed to further verify the feasibility. As a stable decomposition product under PD, SO2 is proved to be applicable for PD early-warning in the field. By selecting the appropriate wavelength range, namely 290-310 nm, ultraviolet derivative spectroscopy is sensitive enough to the trace SO2 in the decomposed gas and the interference of other products can be avoided. Fast Fourier transform could be used for feature extraction in qualitative detection. Concentrations of SO2 and other by-products increase with increasing discharge time and could be affected by the discharge energy and PD type. Ultraviolet detection based on SO2 is effective for PD early-warning but the threshold should still be carefully selected in practice.

  5. Partial trisomy 11q involving chromosome 1 detected by fluorescence in situ hybridization

    SciTech Connect

    McCorquodale, M.; Bereziouk, O.; McCorquodale, D.J.

    1994-09-01

    Partial trisomy 11q was detected in an infant delivered 3-4 weeks prematurely. The phenotype included slanted palpebral fissures, high arched palate, developmental delay, microcephaly, and cardiac defects, all of which occur in the majority of cases with this syndrome. Other features included a column-shaped skull, preauricular pit, single palmar crease, short, broad great toes, flat occiput, unilateral kidney agenesis, and strabismus. Chromosomes obtained from peripheral blood cells revealed the presence of extra material on the long arm of chromosome 1. The G-banding pattern of this extra material indicated that it might be derived from chromosome 1 or 11. Chromosomal {open_quotes}paints{close_quotes} showed that it was not chromosome 1 material, but was chromosome 11 material extending from band q21 to qter. Partial trisomy 11q arising from translocation of the 11q material to chromosome 2, 3, 4, 5, 6, 9, 10, 13, 17, 21, 22, and X has been reported previously, whereas translocation to chromosome 1 has not. The chromosome to which the 11q material is translocated does not alter the most frequent features of the partial trisomy 11q syndrome, but may influence other less common features.

  6. Study on Miniaturized UHF Antennas for Partial Discharge Detection in High-Voltage Electrical Equipment.

    PubMed

    Liu, Jingcun; Zhang, Guogang; Dong, Jinlong; Wang, Jianhua

    2015-01-01

    Detecting partial discharge (PD) is an effective way to evaluate the condition of high-voltage electrical equipment insulation. The UHF detection method has attracted attention due to its high sensitivity, strong interference resistance, and ability to locate PDs. In this paper, a miniaturized equiangular spiral antenna (ESA) for UHF detection that uses a printed circuit board is proposed. I-shaped, L-shaped, and C-shaped microstrip baluns were designed to match the impedance between the ESA and coaxial cable and were verified by a vector network analyzer. For comparison, three other types of UHF antenna were also designed: A microstrip patch antenna, a microstrip slot antenna, and a printed dipole antenna. Their antenna factors were calibrated in a uniform electric field of different frequencies modulated in a gigahertz transverse electromagnetic cell. We performed comparison experiments on PD signal detection using an artificial defect model based on the international IEC 60270 standard. We also conducted time-delay test experiments on the ESA sensor to locate a PD source. It was found that the proposed ESA sensor meets PD signal detection requirements. The sensor's compact size makes it suitable for internal installation in high-voltage electrical equipment. PMID:26610506

  7. Study on Miniaturized UHF Antennas for Partial Discharge Detection in High-Voltage Electrical Equipment

    PubMed Central

    Liu, Jingcun; Zhang, Guogang; Dong, Jinlong; Wang, Jianhua

    2015-01-01

    Detecting partial discharge (PD) is an effective way to evaluate the condition of high-voltage electrical equipment insulation. The UHF detection method has attracted attention due to its high sensitivity, strong interference resistance, and ability to locate PDs. In this paper, a miniaturized equiangular spiral antenna (ESA) for UHF detection that uses a printed circuit board is proposed. I-shaped, L-shaped, and C-shaped microstrip baluns were designed to match the impedance between the ESA and coaxial cable and were verified by a vector network analyzer. For comparison, three other types of UHF antenna were also designed: A microstrip patch antenna, a microstrip slot antenna, and a printed dipole antenna. Their antenna factors were calibrated in a uniform electric field of different frequencies modulated in a gigahertz transverse electromagnetic cell. We performed comparison experiments on PD signal detection using an artificial defect model based on the international IEC 60270 standard. We also conducted time-delay test experiments on the ESA sensor to locate a PD source. It was found that the proposed ESA sensor meets PD signal detection requirements. The sensor’s compact size makes it suitable for internal installation in high-voltage electrical equipment. PMID:26610506

  8. What Colour Is a Shadow?

    ERIC Educational Resources Information Center

    Hughes, S. W.

    2009-01-01

    What colour is a shadow? Black, grey, or some other colour? This article describes how to use a digital camera to test the hypothesis that a shadow under a clear blue sky has a blue tint. A white sheet of A4 paper was photographed in full sunlight and in shadow under a clear blue sky. The images were analysed using a shareware program called…

  9. Detecting Partial Energy Modulation in a Dielectric Laser Accelerator - Oral Presentation

    SciTech Connect

    Lukaczyk, Louis

    2015-08-24

    The Dielectric Laser Acceleration group at SLAC uses micro-fabricated dielectric grating structures and conventional infrared lasers to accelerator electrons. These structures have been estimated to produce an accelerating gradient up to 2 orders of magnitude greater than that produced by conventional RF accelerators. The success of the experiment depends on both the laser damage threshold of the structure and the timing overlap of femtosecond duration laser pulses with the electron bunch. In recent dielectric laser acceleration experiments, the laser pulse was shorter both temporally and spatially than the electron bunch. As a result, the laser is theorized to have interacted with only a small portion of the electron bunch. The detection of this phenomenon, referred to as partial population modulation, required a new approach to the data analysis of the electron energy spectra. A fitting function was designed to separate the accelerated electron population from the unaccelerated electron population. The approach was unsuccessful in detecting acceleration in the partial population modulation data. However, the fitting functions provide an excellent figure of merit for previous data known to contain signatures of acceleration.

  10. Partially reduced graphene oxide based FRET on fiber-optic interferometer for biochemical detection.

    PubMed

    Yao, B C; Wu, Y; Yu, C B; He, J R; Rao, Y J; Gong, Y; Fu, F; Chen, Y F; Li, Y R

    2016-01-01

    Fluorescent resonance energy transfer (FRET) with naturally exceptional selectivity is a powerful technique and widely used in chemical and biomedical analysis. However, it is still challenging for conventional FRET to perform as a high sensitivity compact sensor. Here we propose a novel 'FRET on Fiber' concept, in which a partially reduced graphene oxide (prGO) film is deposited on a fiber-optic modal interferometer, acting as both the fluorescent quencher for the FRET and the sensitive cladding for optical phase measurement due to refractive index changes in biochemical detection. The target analytes induced fluorescence recovery with good selectivity and optical phase shift with high sensitivity are measured simultaneously. The functionalized prGO film coated on the fiber-optic interferometer shows high sensitivities for the detections of metal ion, dopamine and single-stranded DNA (ssDNA), with detection limits of 1.2 nM, 1.3 μM and 1 pM, respectively. Such a prGO based 'FRET on fiber' configuration, bridging the FRET and the fiber-optic sensing technology, may serve as a platform for the realization of series of integrated 'FRET on Fiber' sensors for on-line environmental, chemical, and biomedical detection, with excellent compactness, high sensitivity, good selectivity and fast response. PMID:27010752

  11. Partially reduced graphene oxide based FRET on fiber-optic interferometer for biochemical detection

    PubMed Central

    Yao, B. C.; Wu, Y.; Yu, C. B.; He, J. R.; Rao, Y. J.; Gong, Y.; Fu, F.; Chen, Y. F.; Li, Y. R.

    2016-01-01

    Fluorescent resonance energy transfer (FRET) with naturally exceptional selectivity is a powerful technique and widely used in chemical and biomedical analysis. However, it is still challenging for conventional FRET to perform as a high sensitivity compact sensor. Here we propose a novel ‘FRET on Fiber’ concept, in which a partially reduced graphene oxide (prGO) film is deposited on a fiber-optic modal interferometer, acting as both the fluorescent quencher for the FRET and the sensitive cladding for optical phase measurement due to refractive index changes in biochemical detection. The target analytes induced fluorescence recovery with good selectivity and optical phase shift with high sensitivity are measured simultaneously. The functionalized prGO film coated on the fiber-optic interferometer shows high sensitivities for the detections of metal ion, dopamine and single-stranded DNA (ssDNA), with detection limits of 1.2 nM, 1.3 μM and 1 pM, respectively. Such a prGO based ‘FRET on fiber’ configuration, bridging the FRET and the fiber-optic sensing technology, may serve as a platform for the realization of series of integrated ‘FRET on Fiber’ sensors for on-line environmental, chemical, and biomedical detection, with excellent compactness, high sensitivity, good selectivity and fast response PMID:27010752

  12. Partially reduced graphene oxide based FRET on fiber-optic interferometer for biochemical detection

    NASA Astrophysics Data System (ADS)

    Yao, B. C.; Wu, Y.; Yu, C. B.; He, J. R.; Rao, Y. J.; Gong, Y.; Fu, F.; Chen, Y. F.; Li, Y. R.

    2016-03-01

    Fluorescent resonance energy transfer (FRET) with naturally exceptional selectivity is a powerful technique and widely used in chemical and biomedical analysis. However, it is still challenging for conventional FRET to perform as a high sensitivity compact sensor. Here we propose a novel ‘FRET on Fiber’ concept, in which a partially reduced graphene oxide (prGO) film is deposited on a fiber-optic modal interferometer, acting as both the fluorescent quencher for the FRET and the sensitive cladding for optical phase measurement due to refractive index changes in biochemical detection. The target analytes induced fluorescence recovery with good selectivity and optical phase shift with high sensitivity are measured simultaneously. The functionalized prGO film coated on the fiber-optic interferometer shows high sensitivities for the detections of metal ion, dopamine and single-stranded DNA (ssDNA), with detection limits of 1.2 nM, 1.3 μM and 1 pM, respectively. Such a prGO based ‘FRET on fiber’ configuration, bridging the FRET and the fiber-optic sensing technology, may serve as a platform for the realization of series of integrated ‘FRET on Fiber’ sensors for on-line environmental, chemical, and biomedical detection, with excellent compactness, high sensitivity, good selectivity and fast response

  13. Eigenvector methods for automated detection of electrocardiographic changes in partial epileptic patients.

    PubMed

    Ubeyli, Elif Derya

    2009-07-01

    In this paper, the automated diagnostic systems trained on diverse and composite features were presented for detection of electrocardiographic changes in partial epileptic patients. In practical applications of pattern recognition, there are often diverse features extracted from raw data that require recognizing. Methods of combining multiple classifiers with diverse features are viewed as a general problem in various application areas of pattern recognition. Two types (normal and partial epilepsy) of ECG beats (180 records from each class) were obtained from the Physiobank database. The multilayer perceptron neural network (MLPNN), combined neural network (CNN), mixture of experts (ME), and modified mixture of experts (MME) were tested and benchmarked for their performance on the classification of the studied ECG signals, which were trained on diverse or composite features. Decision making was performed in two stages: feature extraction by eigenvector methods and classification using the classifiers trained on the extracted features. The present research demonstrated that the MME trained on the diverse features achieved accuracy rates (total classification accuracy is 99.44%) that were higher than that of the other automated diagnostic systems. PMID:19273021

  14. Improving detection sensitivity for partial discharge monitoring of high voltage equipment

    NASA Astrophysics Data System (ADS)

    Hao, L.; Lewin, P. L.; Swingler, S. G.

    2008-05-01

    Partial discharge (PD) measurements are an important technique for assessing the health of power apparatus. Previous published research by the authors has shown that an electro-optic system can be used for PD measurement of oil-filled power transformers. A PD signal generated within an oil-filled power transformer may reach a winding and then travel along the winding to the bushing core bar. The bushing, acting like a capacitor, can transfer the high frequency components of the partial discharge signal to its earthed tap point. Therefore, an effective PD current measurement can be implemented at the bushing tap by using a radio frequency current transducer around the bushing-tap earth connection. In addition, the use of an optical transmission technique not only improves the electrical noise immunity and provides the possibility of remote measurement but also realizes electrical isolation and enhances safety for operators. However, the bushing core bar can act as an aerial and in addition noise induced by the electro-optic modulation system may influence overall measurement sensitivity. This paper reports on a machine learning technique, namely the use of a support vector machine (SVM), to improve the detection sensitivity of the system. Comparison between the signal extraction performances of a passive hardware filter and the SVM technique has been assessed. The results obtained from the laboratory-based experiment have been analysed and indicate that the SVM approach provides better performance than the passive hardware filter and it can reliably detect discharge signals with apparent charge greater than 30 pC.

  15. Anisotropic Scattering Shadow Compensation Method for Remote Sensing Image with Consideration of Terrain

    NASA Astrophysics Data System (ADS)

    Wang, Qiongjie; Yan, Li

    2016-06-01

    With the rapid development of sensor networks and earth observation technology, a large quantity of high resolution remote sensing data is available. However, the influence of shadow has become increasingly greater due to the higher resolution shows more complex and detailed land cover, especially under the shadow. Shadow areas usually have lower intensity and fuzzy boundary, which make the images hard to interpret automatically. In this paper, a simple and effective shadow (including soft shadow) detection and compensation method is proposed based on normal data, Digital Elevation Model (DEM) and sun position. First, we use high accuracy DEM and sun position to rebuild the geometric relationship between surface and sun at the time the image shoot and get the hard shadow boundary and sky view factor (SVF) of each pixel. Anisotropic scattering assumption is accepted to determine the soft shadow factor mainly affected by diffuse radiation. Finally, an easy radiation transmission model is used to compensate the shadow area. Compared with the spectral detection method, our detection method has strict theoretical basis, reliable compensation result and minor affected by the image quality. The compensation strategy can effectively improve the radiation intensity of shadow area, reduce the information loss brought by shadow and improve the robustness and efficiency of the classification algorithms.

  16. Multicolor particle shadow accelerometry

    NASA Astrophysics Data System (ADS)

    McPhail, M. J.; Krane, M. H.; Fontaine, A. A.; Goss, L.; Crafton, J.

    2015-04-01

    This paper describes the extension of multicolor particle shadow velocimetry (CPSV) to the measurement of local acceleration in an Eulerian frame of reference. A validation experiment was conducted on a pendulous disk undergoing unsteady rigid body rotation. Angular velocity and acceleration profiles by CPSA are presented along with a comparison to recordings by an accelerometer mounted on the pendulum. CPSA is also demonstrated in a fully-developed turbulent pipe flow. Profiles of standard deviation of the local acceleration in the near wall region ≤ft(0<~{{y}+}<75\\right) are compared to similar measurements by Christensen and Adrian. A favorable comparison is found between CPSA and particle image accelerometry (PIA). The effect of acceleration time delay, or the time between two velocity estimates, on local acceleration estimates is discussed.

  17. View-invariant, partially occluded human detection in still images using part bases and random forest

    NASA Astrophysics Data System (ADS)

    Ko, Byoung Chul; Son, Jung Eun; Nam, Jae-Yeal

    2015-05-01

    This paper presents a part-based human detection method that is invariant to variations in the view of the human and partial occlusion by other objects. First, to address the view variance, parts are extracted from three views: frontal-rear, left profile, and right profile. Then a random set of rectangular parts are extracted from the upper, middle, and lower body as the distribution of Gaussian. Second, an individual part classifier is constructed using random forests across all parts extracted from the three views. From the part locations of each view, part vectors (PVs) are generated and part bases (PB) are also formalized by clustering PVs with their weights of each PB. For testing, a PV for the frontal-rear view is estimated using trained part detectors and is then applied to the trained PB for each view class. Then the distance is computed between the PB and PVs. After applying the same process to the other two views, the final human and its view having the minimum score are selected. The proposed method is applied to pedestrian datasets and its detection precision is, on average, 0.14 higher than related methods, while achieving a faster or comparable processing time with an average of 1.85 s per image.

  18. Absorber height effects on SWA restrictions and 'Shadow' LER

    SciTech Connect

    McClinton, Brittany; Naulleau, Patrick

    2011-02-21

    As extreme-ultraviolet lithography (EUVL) approaches introduction at the 22-nm half-pitch node, several key aspects of absorber height effects remain unexplored. In particular, sidewall angle (SWA) restrictions based on the height of the mask absorber has not yet been clearly defined. In addition, the effects of absorber height on line-edge roughness (LER) from shadowing has not been examined. We make an initial investigation into how tight SWA constraints are and the extent to which shadow LER alters basic LER. Our approach to SWA aims to find SWA restrictions based on 10% of the total CD error budget (10% of CD). Thus, we allot the SWA budget a {+-}0.2nm tolerance for 22nm half-pitch. New with EUVL is the off-axis illumination system. One potential pitfall that must be carefully monitored is the effect of mask absorber height blocking light from reaching, and therefore, correctly detecting, the base edge position of a feature. While mask features can correctly compensate sizing to target at the wafer, the effects of this shadowing on LER have not yet been investigated. Specifically, shadow LER may exacerbate or mitigate the inherent LER on the mask. Shadowing may also cause a difference in the observed LER on the right and left side of the features. We carefully probe this issue for a range of spatial frequencies. We do rigorous aerial image modeling of mask features with a nominal SWA of 80 degrees and correctly sized to target 22nm features measured at the top, 70nm TaN absorber on a 40 bilayer ML mirror with a 2.5nm Ru cap. Simulations were on a 4X system with an ideal pupil of NA = 0.32, illumination wavelength 13.4nm at 6{sup o} off-axis, and disk source shape with partial coherence factor of {sigma} = 0.50. We first implement a defocus offset to the aerial image so that best focus lies at a nominal zero defocus value. We then calculate the depth of focus (DOF) for which the image-log-slope (ILS) delivers a contrast is greater than 50%, an arbitrary standard

  19. How to See Shadows in 3D

    ERIC Educational Resources Information Center

    Parikesit, Gea O. F.

    2014-01-01

    Shadows can be found easily everywhere around us, so that we rarely find it interesting to reflect on how they work. In order to raise curiosity among students on the optics of shadows, we can display the shadows in 3D, particularly using a stereoscopic set-up. In this paper we describe the optics of stereoscopic shadows using simple schematic…

  20. The Moon's Phases and the Self Shadow

    ERIC Educational Resources Information Center

    Young, Timothy; Guy, Mark

    2008-01-01

    In this article, the authors present a new way of teaching the phases of the Moon. Through the introduction of a "self shadow" (an idea of a shadow that is not well-known), they illuminate students' understanding of the phases of the Moon and help them understand the distinction between the shadows that cause eclipses and the shadows that relate…

  1. Cystatin C for early detection of acute kidney injury after laparoscopic partial nephrectomy

    PubMed Central

    Alesawi, Anwar; Nadeau, Geneviève; Bergeron, Alain; Dujardin, Thierry; Lacombe, Louis; Caumartin, Yves

    2014-01-01

    Introduction and Objectives: Mortality due to AKI has not changed significantly over the past 50 years. This is due in part to failure to detect early AKI and to initiate appropriate therapeutic measures. There is therefore a need to identify biomarkers that would improve the early detection of AKI. The objective of this study was to assess whether cystatin C levels obtained at specific timepoints during laparoscopic partial nephrectomy (PN) could be early predictors of AKI. Materials and Methods: Twenty-five patients underwent laparoscopic PN for organ-confined tumors. All procedures were performed by two surgeons in a single institution. Plasma samples were collected preoperatively, and post-unclamping at 5, 20, 120 min and on the day following surgery. Plasma cystatin C was measured by enzyme-linked immunosorbent assay. Correlation between levels of cystatin C and other parameters of interest were assessed in order to define cystatin C ability to predict AKI and loss of renal function following laparoscopic PN. Results: The mean baseline eGFR was 93 ml/min/1.73 m2. Warm ischemia time varied between 16 and 44 min. Post-operative day 1 (POD1) cystatin C levels compared to baseline were increased in 13 (52%) of the patients. There was a high correlation between the difference of POD 1 and baseline value, and eGFR in the immediate postoperative period (r = −0.681; P = 0.0002) and at 12-month follow-up (r = −0.460, P = 0.048). However, the variation in cystatin C levels at earlier timepoints were not associated to AKI nor renal function. Conclusions: High increase in POD 1 cystatin C levels from baseline may help identify patients with AKI and those at higher risk of chronic kidney disease, following laparoscopic PN. PMID:25371605

  2. Characterizing GPS Block IIA Shadow and Post-Shadow Maneuvers

    NASA Astrophysics Data System (ADS)

    Weiss, J.; Bar-Sever, Y.; Bertiger, W.; Desai, S.; Haines, B.; Harvey, N.; Sibthorpe, A.

    2012-04-01

    We characterize GPS Block IIA shadow and post-shadow maneuvers by way of "reverse" precise point positioning (PPP). This technique takes advantage of the non-zero antenna phase center offset, representing the vector from the satellites' center of gravity (CG) to the antenna phase center, to estimate the spacecraft yaw attitude. We begin with a standard GIPSY-based precise orbit determination (POD) solution for the GPS constellation, and use the ground station troposphere, clock, and position estimates, as well as the reduced-dynamic GPS orbit solution as input to a follow-up estimation where the spacecraft body-fixed x, y, and z antenna phase center offsets relative the CG are estimated as unconstrained stochastic white noise parameters every 30 seconds. These estimates directly provide yaw attitude because the spacecraft attitude in the follow-up estimation is set to follow the "velocity frame," where the body-fixed z points towards the Earth, x points along the velocity vector, and y completes the right-handed coordinate system. The estimated antenna offsets absorb errors in the velocity frame attitude model, which does not perform noon and shadow maneuvers, and in turn directly measure spacecraft yaw attitude. In this presentation we utilize the outlined approach to characterize both shadow and post-shadow maneuvers of the GPS Block IIA spacecraft over a period of three years. We fit linear models to the yaw angle estimates during shadow (when the spacecraft traverses umbra) and compare the resulting yaw rate to estimates from standard POD solutions. We particularly focus on changes in yaw rate over time, and on using estimates from reverse PPP to improve nominal yaw rate values. We additionally characterize post-shadow maneuvers for which data are typically removed in POD solutions because the direction and duration of the yaw maneuver to recover nominal attitude are not straightforward to model. We analyze post-shadow maneuvers in terms of yaw angle versus

  3. Impact of ground mover motion and windowing on stationary and moving shadows in synthetic aperture radar imagery

    NASA Astrophysics Data System (ADS)

    Miller, J.; Bishop, E.; Doerry, A.; Raynal, A. M.

    2015-05-01

    This paper describes the impact of ground mover motion and windowing on stationary and moving shadows in Synthetic Aperture Radar (SAR) and video SAR mode imagery. The technique provides a foundation for optimizing algorithms that detect ground movers in SAR imagery. The video SAR mode provides a persistent view of a scene centered at the Motion Compensation Point (MCP). The radar platform follows a circular flight path. Detecting a stationary shadow in a SAR image is important because the shadow indicates a detection of an object with a height component near the shadow. Similarly, the detection of a shadow that moves from frame to frame indicates the detection of a ground mover at the location of the moving shadow. An approach analyzes the impact of windowing in calculating the brightness of a pixel in a stationary, finite-sized shadow region. An extension of the approach describes the pixel brightness for a moving shadow as a function of its velocity. The pixel brightness provides an upper bound on the Probability of Detection (PD) and a lower bound on the Probability of False Alarm (PFA) for a finite-sized, stationary or moving shadow in the presence of homogeneous, ideal clutter. Synthetic data provides shadow characteristics for a radar scenario that lend themselves for detecting a ground mover. The paper presents 2011-2014 flight data collected by General Atomics Aeronautical Systems, Inc. (GA-ASI).

  4. IUPAC-consistent approach to the limit of detection in partial least-squares calibration.

    PubMed

    Allegrini, Franco; Olivieri, Alejandro C

    2014-08-01

    There is currently no well-defined procedure for providing the limit of detection (LOD) in multivariate calibration. Defining an estimator for the LOD in this scenario has shown to be more complex than intuitively extending the traditional univariate definition. For these reasons, although many attempts have been made to arrive at a reasonable convention, additional effort is required to achieve full agreement between the univariate and multivariate LOD definitions. In this work, a novel approach is presented to estimate the LOD in partial least-squares (PLS) calibration. Instead of a single LOD value, an interval of LODs is provided, which depends on the variation of the background composition in the calibration space. This is in contrast with previously proposed univariate extensions of the LOD concept. With the present definition, the LOD interval becomes a parameter characterizing the overall PLS calibration model, and not each test sample in particular, as has been proposed in the past. The new approach takes into account IUPAC official recommendations, and also the latest developments in error-in-variables theory for PLS calibration. Both simulated and real analytical systems have been studied for illustrating the properties of the new LOD concept. PMID:25008998

  5. A circuit-based photovoltaic module simulator with shadow and fault settings

    NASA Astrophysics Data System (ADS)

    Chao, Kuei-Hsiang; Chao, Yuan-Wei; Chen, Jyun-Ping

    2016-03-01

    The main purpose of this study was to develop a photovoltaic (PV) module simulator. The proposed simulator, using electrical parameters from solar cells, could simulate output characteristics not only during normal operational conditions, but also during conditions of partial shadow and fault conditions. Such a simulator should possess the advantages of low cost, small size and being easily realizable. Experiments have shown that results from a proposed PV simulator of this kind are very close to that from simulation software during partial shadow conditions, and with negligible differences during fault occurrence. Meanwhile, the PV module simulator, as developed, could be used on various types of series-parallel connections to form PV arrays, to conduct experiments on partial shadow and fault events occurring in some of the modules. Such experiments are designed to explore the impact of shadow and fault conditions on the output characteristics of the system as a whole.

  6. A coordinate-independent characterization of a black hole shadow

    NASA Astrophysics Data System (ADS)

    Abdujabbarov, Ahmadjon

    2016-07-01

    A large international effort is under way to assess the presence of a shadow in the radio emission from the compact source at the centre of our Galaxy, Sagittarius A* (Sgr A*). If detected, this shadow would provide the first direct evidence of the existence of black holes and that Sgr A* is a supermassive black hole. In addition, the shape of the shadow could be used to learn about extreme gravity near the event horizon and to determine which theory of gravity better describes the observations. The mathematical description of the shadow has so far used a number of simplifying assumptions that are unlikely to be met by the real observational data. We here provide a general formalism to describe the shadow as an arbitrary polar curve expressed in terms of a Legendre expansion. Our formalism does not presume any knowledge of the properties of the shadow, e.g. the location of its centre, and offers a number of routes to characterize the distortions of the curve with respect to reference circles. These distortions can be implemented in a coordinate-independent manner by different teams analysing the same data. We show that the new formalism provides an accurate and robust description of noisy observational data, with smaller error variances when compared to previous approaches for the measurement of the distortion.

  7. Unitarity bound for gluon shadowing

    SciTech Connect

    Kopeliovich, B. Z.; Levin, E.; Potashnikova, I. K.; Schmidt, Ivan

    2009-06-15

    Although at small Bjorken x gluons originated from different nucleons in a nucleus overlap in the longitudinal direction, most of them are still well separated in the transverse plane and therefore cannot fuse. For this reason the gluon density in nuclei cannot drop at small x below a certain bottom bound, which we evaluated in a model independent manner assuming the maximal strength of gluon fusion. We also calculated gluon shadowing in the saturated regime using the Balitsky-Kovchegov equation and found the nuclear ratio to be well above the unitarity bound. The recently updated analysis of parton distributions in nuclei, including BNL Relativistic Heavy Ion Collider (RHIC) data on high-p{sub T} hadron production at forward rapidities, led to strong gluon shadowing. Such strong shadowing and therefore the interpretation of the nuclear modification of the p{sub T} spectra in dA collisions at RHIC seem to be inconsistent with this unitarity bound.

  8. The Shadow War

    ERIC Educational Resources Information Center

    Parrini, Michelle; Williams, Charles F.

    2005-01-01

    For much of the nineteenth century, the U.S. did not allocate many resources to intelligence gathering. Many Americans were wary of espionage, partly because of the disreputable association of espionage with the Pinkerton National Detective Agency, the nation's first private detective and police agency. In the realm of twentieth-century…

  9. Detection of partial melt in continental collision zones using different magnetotelluric tensor relationships: Results from synthetic models and real data

    NASA Astrophysics Data System (ADS)

    LLovet, Joan Campanya i.; Ledo, Juanjo; Jones, Alan G.; Queralt, Pilar; Marcuello, Alex; Liesa, Montserrat; Antón Muñoz, Josep

    2014-05-01

    Three magnetotelluric (MT) tensor relationships - the single-station MT impedance tensor (Z), the single-station vertical geomagnetic transfer function (GTF) and the multiple-station horizontal geomagnetic transfer function (HGTF) - were investigated for their effectiveness in detecting the presence of partial melt in continental collision zones. Realistic synthetic models, based on prior field studies, were used to characterize the sensitivity of each tensor relationship constraining the presence of partial melt at lower-crustal and upper-mantle depths. From the MT response of the synthetic models, each type of data was inverted separately and jointly with the others, thus determining the properties and advantages of each when modeling the subsurface. Non-linear sensitivity tests were carried out to determine the resolution that can be expected in constraining electrical resistivity anomalies associated with the presence of partial melt. Results obtained show which configuration of the HGTF is more sensitive to partial melt. The analysis of partial melt sensitivity was also performed using real data from a MT survey carried out in the Pyrenees. The data comprise a total of 82 broadband MT sites and 29 long period MT sites distributed along four profiles across the Pyrenean mountain range between the Atlantic Ocean and the Mediterranean Sea. Using the results from the synthetic models, real MT data in the Eastern Pyrenees were used to constrain if the partial melting area associated with the Iberian subducted lower crust observed below the Western, the West-central and the Central Pyrenees continues to the East. A non-linear sensitivity test was undertaken to determine the boundary to the east of this geoelectrical anomaly associated with partial melt.

  10. Genetic fusion of single-chain variable fragments to partial spider silk improves target detection in micro- and nanoarrays.

    PubMed

    Thatikonda, Naresh; Delfani, Payam; Jansson, Ronnie; Petersson, Linn; Lindberg, Diana; Wingren, Christer; Hedhammar, My

    2016-03-01

    Immobilizing biomolecules with retained functionality and stability on solid supports is crucial for generation of sensitive immunoassays. However, upon use of conventional immobilization strategies, a major portion of the biomolecules (e.g. antibodies) frequently tends to lose their bioactivity. In this study, we describe a procedure to immobilize human single-chain variable fragment (scFv) via genetic fusion to partial spider silk, which have a high tendency to adhere to solid supports. Two scFvs, directed towards serum proteins, were genetically fused to partial spider silk proteins and expressed as silk fusion proteins in E. coli. Antigen binding ability of scFvs attached to a partial silk protein denoted RC was investigated using microarray analysis, whereas scFvs fused to the NC silk variant were examined using nanoarrays. Results from micro- and nanoarrays confirmed the functionality of scFvs attached to both RC and NC silk, and also for binding of targets in crude serum. Furthermore, the same amount of added scFv gives higher signal intensity when immobilized via partial spider silk compared to when immobilized alone. Together, the results suggest that usage of scFv-silk fusion proteins in immunoassays could improve target detection, in the long run enabling novel biomarkers to be detected in crude serum proteomes. PMID:26470853

  11. The shadow world of superstring theories

    NASA Technical Reports Server (NTRS)

    Kolb, E. W.; Turner, M. S.; Seckel, D.

    1985-01-01

    Some possible astrophysical and cosmological implications of 'shadow matter', a form of matter which only interacts gravitationally with ordinary matter and which may or may not be identical in its properties to ordinary matter, are considered. The possible existence, amount, and location of shadow matter in the solar system are discussed, and the significance of shadow matter for primordial nucleosynthesis, macroscopic asymmetry, baryogenesis, double-bubble inflation, and asymmetric microphysics is addressed. Massive shadow states are discussed.

  12. 47 CFR 80.769 - Shadow loss.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 47 Telecommunication 5 2014-10-01 2014-10-01 false Shadow loss. 80.769 Section 80.769... MARITIME SERVICES Standards for Computing Public Coast Station VHF Coverage § 80.769 Shadow loss. Where the transmission path is obstructed the received signal must be adjusted to include shadow loss. Attenuation due...

  13. 47 CFR 80.769 - Shadow loss.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 47 Telecommunication 5 2012-10-01 2012-10-01 false Shadow loss. 80.769 Section 80.769... MARITIME SERVICES Standards for Computing Public Coast Station VHF Coverage § 80.769 Shadow loss. Where the transmission path is obstructed the received signal must be adjusted to include shadow loss. Attenuation due...

  14. Casting Shadows in the Science Classroom.

    ERIC Educational Resources Information Center

    Nolan, Kathleen

    2003-01-01

    Uses the metaphor of shadows in a critical exploration of what it means to know and how the cultures of classrooms have shaped these images of knowing. Directs attention to objects that cast shadows on the learning and knowing of mathematics and science through the voices of preservice teachers. Discusses shadow casting toward textbooks, teachers,…

  15. 47 CFR 80.769 - Shadow loss.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 47 Telecommunication 5 2013-10-01 2013-10-01 false Shadow loss. 80.769 Section 80.769... MARITIME SERVICES Standards for Computing Public Coast Station VHF Coverage § 80.769 Shadow loss. Where the transmission path is obstructed the received signal must be adjusted to include shadow loss. Attenuation due...

  16. Shadows: Young Taiwanese Children's Views and Understanding

    ERIC Educational Resources Information Center

    Chen, Shu-Min

    2009-01-01

    The purpose of this study was to examine young children's views about shadows. Young children hear references to or are involved in many scientific experiences in their everyday lives, and shadows are a part of children's everyday experiences. Young children may have constructed their knowledge about shadows through their daily experiences.…

  17. 47 CFR 80.769 - Shadow loss.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 47 Telecommunication 5 2010-10-01 2010-10-01 false Shadow loss. 80.769 Section 80.769... MARITIME SERVICES Standards for Computing Public Coast Station VHF Coverage § 80.769 Shadow loss. Where the transmission path is obstructed the received signal must be adjusted to include shadow loss. Attenuation due...

  18. Helping Students Construct Understanding about Shadows

    ERIC Educational Resources Information Center

    Barrow, Lloyd H.

    2012-01-01

    The study of shadows is a common elementary science topic that facilitates students' development of understanding about light and associated waves. All elementary students have observed numerous shadows, but need assistance in developing understanding. Previous research studies about shadows were utilized in organizing aspects associated with…

  19. 47 CFR 80.769 - Shadow loss.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 47 Telecommunication 5 2011-10-01 2011-10-01 false Shadow loss. 80.769 Section 80.769... MARITIME SERVICES Standards for Computing Public Coast Station VHF Coverage § 80.769 Shadow loss. Where the transmission path is obstructed the received signal must be adjusted to include shadow loss. Attenuation due...

  20. Shedding Light on Shadow Education

    ERIC Educational Resources Information Center

    Kobakhidze, Magda Nutsa

    2015-01-01

    This essay review examines four different movies that directly or indirectly refer to the theme of private tutoring or, as it is widely called, shadow education. The movies, directed in locations as diverse as India, Turkey, and Cambodia, are all made from a critical perspective. The directors demonstrate challenges in public education systems and…

  1. The Greatest Shadow on Earth

    ERIC Educational Resources Information Center

    Hughes, Stephen; Wimmer, Jason; Towsey, Michael; Fahmi, Marco; Winslett, Greg; Dubler, Gabriel; Le Prou, Angela; Loose, David

    2014-01-01

    In a total solar eclipse, the Moon completely covers the Sun, casting a shadow several hundred km wide across the face of the Earth. This paper describes observations of the 14 November 2012 total eclipse of the Sun visible from north Queensland, Australia. The edge of the umbra was captured on video during totality, and this video is provided for…

  2. Video Job Shadows. Project SEED.

    ERIC Educational Resources Information Center

    Kucinkas, Gene; Noyce, Gary

    Video Job Shadows encourages students to develop questions about a job and offers them the chance to videotape a business person answering those questions about his or her job. The program can be an effective method of teaching high school students about the world of work and the specific requirements and responsibilities of some jobs in their…

  3. A spectrum of shadowed mirroring.

    PubMed

    Wanamaker, Melissa C

    2012-04-01

    The central focus of this paper is to explore and extend Kohut's theory of maternal mirroring and to place it within the current context of psychoanalytic thinking. Kohut believed a child must experience "positive" mirroring from his or her mother in infancy and beyond to ensure development of a healthy self. Kohut alludes, however, to a possible situation in which the mother's face, metaphorically a mirror, can appear "faceless" to her child. From this I have inferred the concept of what I shall call "shadowed mirroring." Clinical and literary examples show that distorted, "shadowed" mirroring appears on a spectrum, with passive mirroring at one end and hostile (either verbal or nonverbal) mirroring on the other; some individuals experience both. I then consider how "shadowed mirroring," especially hostile mirroring, can be understood within the twin contexts of the overall mother-child relationship and present-day Intersubjective/Relational thinking that is both bidirectional and co-constructed. Shadowed mirroring can lead to severe personality dysfunction along the borderline-narcissistic range, as well as to difficulties in the areas of identity formation, failure of self-cohesiveness, and the blunting of certain humane qualities like empathy. PMID:22489812

  4. Detection of nitrifiers and evaluation of partial nitrification for wastewater treatment: A review.

    PubMed

    Ge, Shijian; Wang, Shanyun; Yang, Xiong; Qiu, Shuang; Li, Baikun; Peng, Yongzhen

    2015-12-01

    Partial nitrification has gained broad interests in the biological nitrogen removal (BNR) from wastewater, since it alleviates carbon limitation issues and acts as a shortcut nitrogen removal system combined with anaerobic ammonium oxidation (Anammox) process. The occurrence and maintenance of partial nitrification relies on various conditions, which favor ammonium oxidizing bacteria (AOB) but inhibit or limit nitrite oxidizing bacteria (NOB). The studies of the AOB and NOB activities have been conducted by state-of-the-art molecular techniques, such as Polymerase Chain Reaction (PCR), Quantitative PCR, denaturing gradient gel electrophoresis (DGGE), Fluorescence in situ hybridization (FISH) technique, Terminal Restriction Fragment Length Polymorphism (T-RFLP), Live/Dead BacLight, and quinone profile. Furthermore, control strategies for obtaining partial nitrification are mainly focused on the pH, temperature, dissolved oxygen concentration, real-time aeration control, sludge retention time, substrate concentration, alternating anoxic and aerobic operation, inhibitor and ultrasonic treatment. Existing problems and further perspectives for the scale-up of partial nitrification are also proposed and suggested. PMID:25796420

  5. Fiber Optic Sensor for Acoustic Detection of Partial Discharges in Oil-Paper Insulated Electrical Systems

    PubMed Central

    Posada-Roman, Julio; Garcia-Souto, Jose A.; Rubio-Serrano, Jesus

    2012-01-01

    A fiber optic interferometric sensor with an intrinsic transducer along a length of the fiber is presented for ultrasound measurements of the acoustic emission from partial discharges inside oil-filled power apparatus. The sensor is designed for high sensitivity measurements in a harsh electromagnetic field environment, with wide temperature changes and immersion in oil. It allows enough sensitivity for the application, for which the acoustic pressure is in the range of units of Pa at a frequency of 150 kHz. In addition, the accessibility to the sensing region is guaranteed by immune fiber-optic cables and the optical phase sensor output. The sensor design is a compact and rugged coil of fiber. In addition to a complete calibration, the in-situ results show that two types of partial discharges are measured through their acoustic emissions with the sensor immersed in oil. PMID:22666058

  6. PARTIAL LEAST SQUARES REGRESSION OF HYPERSPECTRAL IMAGES FOR CONTAMINATION DETECTION ON POULTRY CARCASSES

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Abstract The U.S. Department of Agriculture has developed multispectral and hyperspectral imaging systems to detect faecal contaminants. Until recently, the hyperspectral imaging system has been used as a research tool to detect a few optimum wavelengths for use in a multispectral imaging system. ...

  7. Partial Least Squares Regression of Hyperspectral Images for Contaminant Detection on Poultry Carcasses

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The U.S. Department of Agriculture has developed multispectral and hyperspectral imaging systems to detect faecal contaminants. Until recently, the hyperspectral imaging system has been used as a research tool to detect a few optimum wavelengths for use in a multispectral imaging system. However, ...

  8. Fabrication of optical fiber sensor based on double-layer SU-8 diaphragm and the partial discharge detection

    NASA Astrophysics Data System (ADS)

    Shang, Ya-na; Ni, Qing-yan; Ding, Ding; Chen, Na; Wang, Ting-yun

    2015-01-01

    In this paper, a partial discharge detection system is proposed using an optical fiber Fabry-Perot (FP) interferometric sensor, which is fabricated by photolithography. SU-8 photoresist is employed due to its low Young's modulus and potentially high sensitivity for ultrasound detection. The FP cavity is formed by coating the fiber end face with two layers of SU-8 so that the cavity can be controlled by the thickness of the middle layer of SU-8. Static pressure measurement experiments are done to estimate the sensing performance. The results show that the SU-8 based sensor has a sensitivity of 154.8 nm/kPa, which is much higher than that of silica based sensor under the same condition. Moreover, the sensor is demonstrated successfully to detect ultrasound from electrode discharge.

  9. Shadows of CPR black holes and tests of the Kerr metric

    NASA Astrophysics Data System (ADS)

    Ghasemi-Nodehi, M.; Li, Zilong; Bambi, Cosimo

    2015-07-01

    We study the shadow of the Cardoso-Pani-Rico black hole for different values of the black hole spin , the deformation parameters and , and the viewing angle i. We find that the main impact of the deformation parameter is the change of the size of the shadow, while the deformation parameter affects the shape of its boundary. In general, it is impossible to test the Kerr metric, because the shadow of a Kerr black hole can be reproduced quite well by a black hole with non-vanishing or . Deviations from the Kerr geometry could be constrained in the presence of high quality data and in the favorable case of a black hole with high values of and i. However, the shadows of some black holes with non-vanishing present peculiar features and the possible detection of these shadows could unambiguously distinguish these objects from the standard Kerr black holes of general relativity.

  10. Speckles and Shadow Bands

    NASA Astrophysics Data System (ADS)

    Mason, Brian D.

    1995-03-01

    Speckle interferometry has for the past two decades provided a means to measure very accurate relative positions of binary stars, data crucial to the fundamental determination of basic stellar parameters. As a technique for observing small angular separations speckle interferometry is exceeded only by long baseline interferometry (a technique still in infancy) and the observation of lunar occultation phenomena. As the moon passes in front of stars the light coming from those stars is occulted. Occultations of binary stars can determine relative intensities and can measure separations which are comparable to those measured by long-baseline interferometers. The data are difficult to interpret since the measured separation is a projection of the true angular separation and non-standard filters are often used. No complete listing of all occultation measures has been published since the compilation of David Evans (IAU Colloquium No. 62, Current Techniques in Double and Multiple Star Research, Lowell Observatory Bulletin No. 167, 1981, eds. Harrington, R.A. \\& Franz, O.G., Lowell Observatory, Flagstaff). The dissertation presents 772 measures of 357 systems, an increase of 60\\% over the Evans catalog. The methodology of speckle interferometry is presented, followed by 362 re-reduction measures and 253 new measures. The re-reduction measures were cases where prior analysis showed no companion. With improved reduction algorithms, detection frequency significantly increased. One observation in eight previously showing no companion produced a measurable result. Results were obtained with the 1.8-m Perkins telescope of Lowell Observatory, the 2.5-m Hooker telescope of Mt. Wilson Observatory, the 3.8-m Mayall telescope of Kitt Peak National Observatory and the 4.0-m telescope at Cerro Tololo InterAmerican Observatory. All but 130 of the occultation objects have speckle observations. The likelihood of future detection by speckle is considered. An analysis of 131 negative

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

    NASA Astrophysics Data System (ADS)

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

    2009-02-01

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

  12. Shadow correction in high dynamic range images for generating orthophotos

    NASA Astrophysics Data System (ADS)

    Suzuki, Hideo; Chikatsu, Hirofumi

    2011-07-01

    High dynamic range imagery is widely used in remote sensing. With the widespread use of aerial digital cameras such as the DMC, ADS40, RMK-D, and UltraCamD, high dynamic range imaging is generally expected for generating minuteness orthophotos in digital aerial photogrammetry. However, high dynamic range images (12-bit, 4,096 gray levels) are generally compressed into an 8-bit depth digital image (256 gray levels) owing to huge amount of data and interface with peripherals such as monitors and printers. This means that a great deal of image data is eliminated from the original image, and this introduces a new shadow problem. In particular, the influence of shadows in urban areas causes serious problems when generating minuteness orthophotos and performing house detection. Therefore, shadow problems can be solved by addressing the image compression problems. There is a large body of literature on image compression techniques such as logarithmic compression and tone mapping algorithms. However, logarithmic compression tends to cause loss of details in dark and/or light areas. Furthermore, the logarithmic method intends to operate on the full scene. This means that high-resolution luminance information can not be obtained. Even though tone mapping algorithms have the ability to operate over both full scene and local scene, background knowledge is required. To resolve the shadow problem in digital aerial photogrammetry, shadow areas should be recognized and corrected automatically without the loss of luminance information. To this end, a practical shadow correction method using 12-bit real data acquired by DMC is investigated in this paper.

  13. The Inverted Snow Globe Shadow

    NASA Astrophysics Data System (ADS)

    Ribeiro, Jair Lúcio Prados

    2015-01-01

    Our high school optics course finishes with an assignment that students usually appreciate. They must take pictures of everyday situations representing optical phenomena such as reflection, refraction, or dispersion, and post them on Instagram.1 When the photos were presented to the class, one student revealed an intriguing photo, similar to Fig. 1, showing a snow globe exposed to sunlight and its inverted shadow. This paper offers an explanation of the problem, which occurs due to light refraction from the globe.

  14. Managed care and shadow price.

    PubMed

    Ma, Ching-To A

    2004-02-01

    A managed-care company must decide on allocating resources of many services to many groups of enrollees. The profit-maximizing allocation rule is characterized. For each group, the marginal utilities across all services are equalized. The equilibrium has an enrollee group shadow price interpretation. The equilibrium spending allocation can be implemented by letting utilitarian physicians decide on service spending on an enrollee group subject to a budget for the group. PMID:14737757

  15. Selecting Observation Platforms for Optimized Anomaly Detectability under Unreliable Partial Observations

    SciTech Connect

    Wen-Chiao Lin; Humberto E. Garcia; Tae-Sic Yoo

    2011-06-01

    Diagnosers for keeping track on the occurrences of special events in the framework of unreliable partially observed discrete-event dynamical systems were developed in previous work. This paper considers observation platforms consisting of sensors that provide partial and unreliable observations and of diagnosers that analyze them. Diagnosers in observation platforms typically perform better as sensors providing the observations become more costly or increase in number. This paper proposes a methodology for finding an observation platform that achieves an optimal balance between cost and performance, while satisfying given observability requirements and constraints. Since this problem is generally computational hard in the framework considered, an observation platform optimization algorithm is utilized that uses two greedy heuristics, one myopic and another based on projected performances. These heuristics are sequentially executed in order to find best observation platforms. The developed algorithm is then applied to an observation platform optimization problem for a multi-unit-operation system. Results show that improved observation platforms can be found that may significantly reduce the observation platform cost but still yield acceptable performance for correctly inferring the occurrences of special events.

  16. Study on the Application of an Ultra-High-Frequency Fractal Antenna to Partial Discharge Detection in Switchgears

    PubMed Central

    Yao, Chenguo; Chen, Pan; Huang, Congjian; Chen, Yu; Qiao, Panpan

    2013-01-01

    The ultra-high-frequency (UHF) method is used to analyze the insulation condition of electric equipment by detecting the UHF electromagnetic (EM) waves excited by partial discharge (PD). As part of the UHF detection system, the UHF sensor determines the detection system performance in signal extraction and recognition. In this paper, a UHF antenna sensor with the fractal structure for PD detection in switchgears was designed by means of modeling, simulation and optimization. This sensor, with a flat-plate structure, had two resonance frequencies of 583 MHz and 732 MHz. In the laboratory, four kinds of insulation defect models were positioned in the testing switchgear for typical PD tests. The results show that the sensor could reproduce the electromagnetic waves well. Furthermore, to optimize the installation position of the inner sensor for achieving best detection performance, the precise simulation model of switchgear was developed to study the propagation characteristics of UHF signals in switchgear by finite-difference time-domain (FDTD) method. According to the results of simulation and verification test, the sensor should be positioned at the right side of bottom plate in the front cabinet. This research established the foundation for the further study on the application of UHF technique in switchgear PD online detection. PMID:24351641

  17. Shadow Enhancers Are Pervasive Features of Developmental Regulatory Networks.

    PubMed

    Cannavò, Enrico; Khoueiry, Pierre; Garfield, David A; Geeleher, Paul; Zichner, Thomas; Gustafson, E Hilary; Ciglar, Lucia; Korbel, Jan O; Furlong, Eileen E M

    2016-01-11

    Embryogenesis is remarkably robust to segregating mutations and environmental variation; under a range of conditions, embryos of a given species develop into stereotypically patterned organisms. Such robustness is thought to be conferred, in part, through elements within regulatory networks that perform similar, redundant tasks. Redundant enhancers (or "shadow" enhancers), for example, can confer precision and robustness to gene expression, at least at individual, well-studied loci. However, the extent to which enhancer redundancy exists and can thereby have a major impact on developmental robustness remains unknown. Here, we systematically assessed this, identifying over 1,000 predicted shadow enhancers during Drosophila mesoderm development. The activity of 23 elements, associated with five genes, was examined in transgenic embryos, while natural structural variation among individuals was used to assess their ability to buffer against genetic variation. Our results reveal three clear properties of enhancer redundancy within developmental systems. First, it is much more pervasive than previously anticipated, with 64% of loci examined having shadow enhancers. Their spatial redundancy is often partial in nature, while the non-overlapping function may explain why these enhancers are maintained within a population. Second, over 70% of loci do not follow the simple situation of having only two shadow enhancers-often there are three (rols), four (CadN and ade5), or five (Traf1), at least one of which can be deleted with no obvious phenotypic effects. Third, although shadow enhancers can buffer variation, patterns of segregating variation suggest that they play a more complex role in development than generally considered. PMID:26687625

  18. Shadow Effect on Photovoltaic Potentiality Analysis Using 3d City Models

    NASA Astrophysics Data System (ADS)

    Alam, N.; Coors, V.; Zlatanova, S.; Oosterom, P. J. M.

    2012-07-01

    Due to global warming, green-house effect and various other drawbacks of existing energy sources, renewable energy like Photovoltaic system is being popular for energy production. The result of photovoltaic potentiality analysis depends on data quality and parameters. Shadow rapidly decreases performance of the Photovoltaic system and it always changes due to the movement of the sun. Solar radiation incident on earth's atmosphere is relatively constant but the radiation at earth's surface varies due to absorption, scattering, reflection, change in spectral content, diffuse component, water vapor, clouds and pollution etc. In this research, it is being investigated that how efficiently real-time shadow can be detected for both direct and diffuse radiation considering reflection and other factors in contrast with the existing shadow detection methods using latest technologies and what is the minimum quality of data required for this purpose. Of course, geometric details of the building geometry and surroundings directly affect the calculation of shadows. In principle, 3D city models or point clouds, which contain roof structure, vegetation, thematically differentiated surface and texture, are suitable to simulate exact real-time shadow. This research would develop an automated procedure to measure exact shadow effect from the 3D city models and a long-term simulation model to determine the produced energy from the photovoltaic system. In this paper, a developed method for detecting shadow for direct radiation has been discussed with its result using a 3D city model to perform a solar energy potentiality analysis.

  19. A unified approach to theories of shadowing

    NASA Astrophysics Data System (ADS)

    Kulczycki, Marcin

    2014-05-01

    This paper introduces the notion of a general approximation property, which encompasses many existing types of shadowing. It is proven that there exists a metric space X such that the sets of maps with many types of general approximation properties (including the classic shadowing, the L p -shadowing, limit shadowing, and the s-limit shadowing) are not dense in C( X), S( X), and H( X) (the space of continuous self-maps of X, continuous surjections of X onto itself, and self-homeomorphisms of X) and that there exists a manifold M such that the sets of maps with general approximation properties of nonlocal type (including the average shadowing property and the asymptotic average shadowing property) are not dense in C( M), S( M), and H( M). Furthermore, it is proven that the sets of maps with a wide range of general approximation properties (including the classic shadowing, the L p -shadowing, and the s-limit shadowing) are dense in the space of continuous self-maps of the Cantor set. A condition is given that guarantees transfer of general approximation property from a map on X to the map induced by it on the hyperspace of X. It is also proven that the transfer in the opposite direction always takes place.

  20. Low-Pass Filtered Volumetric Shadows.

    PubMed

    Ament, Marco; Sadlo, Filip; Dachsbacher, Carsten; Weiskopf, Daniel

    2014-12-01

    We present a novel and efficient method to compute volumetric soft shadows for interactive direct volume visualization to improve the perception of spatial depth. By direct control of the softness of volumetric shadows, disturbing visual patterns due to hard shadows can be avoided and users can adapt the illumination to their personal and application-specific requirements. We compute the shadowing of a point in the data set by employing spatial filtering of the optical depth over a finite area patch pointing toward each light source. Conceptually, the area patch spans a volumetric region that is sampled with shadow rays; afterward, the resulting optical depth values are convolved with a low-pass filter on the patch. In the numerical computation, however, to avoid expensive shadow ray marching, we show how to align and set up summed area tables for both directional and point light sources. Once computed, the summed area tables enable efficient evaluation of soft shadows for each point in constant time without shadow ray marching and the softness of the shadows can be controlled interactively. We integrated our method in a GPU-based volume renderer with ray casting from the camera, which offers interactive control of the transfer function, light source positions, and viewpoint, for both static and time-dependent data sets. Our results demonstrate the benefit of soft shadows for visualization to achieve user-controlled illumination with many-point lighting setups for improved perception combined with high rendering speed. PMID:26356957

  1. Shadow imaging of geosynchronous satellites

    NASA Astrophysics Data System (ADS)

    Douglas, Dennis Michael

    Geosynchronous (GEO) satellites are essential for modern communication networks. If communication to a GEO satellite is lost and a malfunction occurs upon orbit insertion such as a solar panel not deploying there is no direct way to observe it from Earth. Due to the GEO orbit distance of ~36,000 km from Earth's surface, the Rayleigh criteria dictates that a 14 m telescope is required to conventionally image a satellite with spatial resolution down to 1 m using visible light. Furthermore, a telescope larger than 30 m is required under ideal conditions to obtain spatial resolution down to 0.4 m. This dissertation evaluates a method for obtaining high spatial resolution images of GEO satellites from an Earth based system by measuring the irradiance distribution on the ground resulting from the occultation of the satellite passing in front of a star. The representative size of a GEO satellite combined with the orbital distance results in the ground shadow being consistent with a Fresnel diffraction pattern when observed at visible wavelengths. A measurement of the ground shadow irradiance is used as an amplitude constraint in a Gerchberg-Saxton phase retrieval algorithm that produces a reconstruction of the satellite's 2D transmission function which is analogous to a reverse contrast image of the satellite. The advantage of shadow imaging is that a terrestrial based redundant set of linearly distributed inexpensive small telescopes, each coupled to high speed detectors, is a more effective resolved imaging system for GEO satellites than a very large telescope under ideal conditions. Modeling and simulation efforts indicate sub-meter spatial resolution can be readily achieved using collection apertures of less than 1 meter in diameter. A mathematical basis is established for the treatment of the physical phenomena involved in the shadow imaging process. This includes the source star brightness and angular extent, and the diffraction of starlight from the satellite

  2. Recurrent neural networks with composite features for detection of electrocardiographic changes in partial epileptic patients.

    PubMed

    Ubeyli, Elif Derya

    2008-03-01

    The aim of this study is to evaluate the diagnostic accuracy of the recurrent neural networks (RNNs) with composite features (wavelet coefficients and Lyapunov exponents) on the electrocardiogram (ECG) signals. Two types of ECG beats (normal and partial epilepsy) were obtained from the MIT-BIH database. The multilayer perceptron neural networks (MLPNNs) were also tested and benchmarked for their performance on the classification of the ECG signals. Decision making was performed in two stages: computing composite features which were then input into the classifiers and classification using the classifiers trained with the Levenberg-Marquardt algorithm. The research demonstrated that the wavelet coefficients and the Lyapunov exponents are the features which well represent the ECG signals and the RNN trained on these features achieved high classification accuracies. PMID:18275945

  3. Lameness detection challenges in automated milking systems addressed with partial least squares discriminant analysis.

    PubMed

    Garcia, E; Klaas, I; Amigo, J M; Bro, R; Enevoldsen, C

    2014-12-01

    Lameness causes decreased animal welfare and leads to higher production costs. This study explored data from an automatic milking system (AMS) to model on-farm gait scoring from a commercial farm. A total of 88 cows were gait scored once per week, for 2 5-wk periods. Eighty variables retrieved from AMS were summarized week-wise and used to predict 2 defined classes: nonlame and clinically lame cows. Variables were represented with 2 transformations of the week summarized variables, using 2-wk data blocks before gait scoring, totaling 320 variables (2 × 2 × 80). The reference gait scoring error was estimated in the first week of the study and was, on average, 15%. Two partial least squares discriminant analysis models were fitted to parity 1 and parity 2 groups, respectively, to assign the lameness class according to the predicted probability of being lame (score 3 or 4/4) or not lame (score 1/4). Both models achieved sensitivity and specificity values around 80%, both in calibration and cross-validation. At the optimum values in the receiver operating characteristic curve, the false-positive rate was 28% in the parity 1 model, whereas in the parity 2 model it was about half (16%), which makes it more suitable for practical application; the model error rates were, 23 and 19%, respectively. Based on data registered automatically from one AMS farm, we were able to discriminate nonlame and lame cows, where partial least squares discriminant analysis achieved similar performance to the reference method. PMID:25282423

  4. Enhanced Community Structure Detection in Complex Networks with Partial Background Information

    NASA Astrophysics Data System (ADS)

    Zhang, Zhong-Yuan; Sun, Kai-Di; Wang, Si-Qi

    2013-11-01

    Community structure detection in complex networks is important since it can help better understand the network topology and how the network works. However, there is still not a clear and widely-accepted definition of community structure, and in practice, different models may give very different results of communities, making it hard to explain the results. In this paper, different from the traditional methodologies, we design an enhanced semi-supervised learning framework for community detection, which can effectively incorporate the available prior information to guide the detection process and can make the results more explainable. By logical inference, the prior information is more fully utilized. The experiments on both the synthetic and the real-world networks confirm the effectiveness of the framework.

  5. Dark Matter Trapping by Stellar Bars: The Shadow Bar

    NASA Astrophysics Data System (ADS)

    Petersen, Michael S.; Weinberg, Martin D.; Katz, Neal

    2016-09-01

    We investigate the complex interactions between the stellar disc and the dark-matter halo during bar formation and evolution using N-body simulations with fine temporal resolution and optimally chosen spatial resolution. We find that the forming stellar bar traps dark matter in the vicinity of the stellar bar into bar-supporting orbits. We call this feature the shadow bar. The shadow bar modifies both the location and magnitude of the angular momentum transfer between the disc and dark matter halo and adds 10 per cent to the mass of the stellar bar over 4 Gyr. The shadow bar is potentially observable by its density and velocity signature in spheroid stars and by direct dark matter detection experiments. Numerical tests demonstrate that the shadow bar can diminish the rate of angular momentum transport from the bar to the dark matter halo by more than a factor of three over the rate predicted by dynamical friction with an untrapped dark halo, and thus provides a possible physical explanation for the observed prevalence of fast bars in nature.

  6. Construction of Discrete Time Shadow Price

    SciTech Connect

    Rogala, Tomasz Stettner, Lukasz

    2015-12-15

    In the paper expected utility from consumption over finite time horizon for discrete time markets with bid and ask prices and strictly concave utility function is considered. The notion of weak shadow price, i.e. an illiquid price, depending on the portfolio, under which the model without bid and ask price is equivalent to the model with bid and ask price is introduced. Existence and the form of weak shadow price is shown. Using weak shadow price usual (called in the paper strong) shadow price is then constructed.

  7. Implementation of a novel double-side technique for partial discharge detection and location in covered conductor overhead distribution networks

    NASA Astrophysics Data System (ADS)

    He, Weisheng; Li, Hongjie; Liang, Deliang; Sun, Haojie; Yang, Chenbo; Wei, Jinqu; Yuan, Zhijian

    2015-12-01

    Partial discharge (PD) detection has proven to be one of the most acceptable techniques for on-line condition monitoring and predictive maintenance of power apparatus. A powerful tool for detecting PD in covered-conductor (CC) lines is urgently needed to improve the asset management of CC overhead distribution lines. In this paper, an appropriate, portable and simple system designed to detect PD activity in CC lines and ultimately pinpoint the PD source is developed and tested. The system is based on a novel double-side synchronised PD measurement technique driven by pulse injection. Emphasis is placed on the proposed PD-location mechanism and hardware structure, with descriptions of the pulse-injection process, detection device, synchronisation principle and PD-location algorithm. The system is simulated using ATP-EMTP, and the simulated results are found to be consistent with the actual simulation layout. For further validation, the capability of the system is tested in a high-voltage laboratory experiment using a 10-kV CC line with cross-linked polyethylene insulation.

  8. The greatest shadow on Earth

    NASA Astrophysics Data System (ADS)

    Hughes, Stephen; Wimmer, Jason; Towsey, Michael; Fahmi, Marco; Winslett, Greg; Dubler, Gabriel; Le Prou, Angela; Loose, David

    2014-01-01

    In a total solar eclipse, the Moon completely covers the Sun, casting a shadow several hundred km wide across the face of the Earth. This paper describes observations of the 14 November 2012 total eclipse of the Sun visible from north Queensland, Australia. The edge of the umbra was captured on video during totality, and this video is provided for teaching purposes. A series of simple ‘kitchen’ experiments are described which demonstrate the ‘sunset’ effect seen on the horizon during a total solar eclipse and also the curved umbra seen in the sky when the eclipsed Sun is relatively close to the horizon.

  9. A Diagnoser Algorithm for Anomaly Detection in DEDS under Partial Unreliable Observations: Characterization and Inclusion in Sensor Configuration Optimizaton

    SciTech Connect

    Wen-Chiao Lin; Humberto Garcia; Tae-Sic Yoo

    2013-03-01

    Complex engineering systems have to be carefully monitored to meet demanding performance requirements, including detecting anomalies in their operations. There are two major monitoring challenges for these systems. The first challenge is that information collected from the monitored system is often partial and/or unreliable, in the sense that some occurred events may not be reported and/or may be reported incorrectly (e.g., reported as another event). The second is that anomalies often consist of sequences of event patterns separated in space and time. This paper introduces and analyzes a diagnoser algorithm that meets these challenges for detecting and counting occurrences of anomalies in engineering systems. The proposed diagnoser algorithm assumes that models are available for characterizing plant operations (via stochastic automata) and sensors (via probabilistic mappings) used for reporting partial and unreliable information. Methods for analyzing the effects of model uncertainties on the diagnoser performance are also discussed. In order to select configurations that reduce sensor costs, while satisfying diagnoser performance requirements, a sensor configuration selection algorithm developed in previous work is then extended for the proposed diagnoser algorithm. The proposed algorithms and methods are then applied to a multi-unit-operation system, which is derived from an actual facility application. Results show that the proposed diagnoser algorithm is able to detect and count occurrences of anomalies accurately and that its performance is robust to model uncertainties. Furthermore, the sensor configuration selection algorithm is able to suggest optimal sensor configurations with significantly reduced costs, while still yielding acceptable performance for counting the occurrences of anomalies.

  10. West side, oblique, partially hidden by trees, utility safety fence, ...

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

    West side, oblique, partially hidden by trees, utility safety fence, and the deep shadow of the 1962 annex. View to northeast. - San Bernardino Valley College, Library, 701 South Mount Vernon Avenue, San Bernardino, San Bernardino County, CA

  11. The Dark Side of EDX Tomography: Modeling Detector Shadowing to Aid 3D Elemental Signal Analysis.

    PubMed

    Yeoh, Catriona S M; Rossouw, David; Saghi, Zineb; Burdet, Pierre; Leary, Rowan K; Midgley, Paul A

    2015-06-01

    A simple model is proposed to account for the loss of collected X-ray signal by the shadowing of X-ray detectors in the scanning transmission electron microscope. The model is intended to aid the analysis of three-dimensional elemental data sets acquired using energy-dispersive X-ray tomography methods where shadow-free specimen holders are unsuitable or unavailable. The model also provides a useful measure of the detection system geometry. PMID:25790959

  12. A 65-kV insulated gate bipolar transistor switch applied in damped AC voltages partial discharge detection system.

    PubMed

    Jiang, J; Ma, G M; Luo, D P; Li, C R; Li, Q M; Wang, W

    2014-02-01

    Damped AC voltages detection system (DAC) is a productive way to detect the faults in power cables. To solve the problems of large volume, complicated structure and electromagnetic interference in existing switches, this paper developed a compact solid state switch based on electromagnetic trigger, which is suitable for DAC test system. Synchronous electromagnetic trigger of 32 Insulated Gate Bipolar Transistors (IGBTs) in series was realized by the topological structure of single line based on pulse width modulation control technology. In this way, external extension was easily achieved. Electromagnetic trigger and resistor-capacitor-diode snubber circuit were optimized to reduce the switch turn-on time and circular layout. Epoxy encapsulating was chosen to enhance the level of partial discharge initial voltage (PDIV). The combination of synchronous trigger and power supply is proposed to reduce the switch volume. Moreover, we have overcome the drawback of the electromagnetic interference and improved the detection sensitivity of DAC by using capacitor storage energy to maintain IGBT gate driving voltage. The experimental results demonstrated that the solid-state switch, with compact size, whose turn-on time was less than 400 ns and PDIV was more than 65 kV, was able to meet the actual demands of 35 kV DAC test system. PMID:24593382

  13. A 65-kV insulated gate bipolar transistor switch applied in damped AC voltages partial discharge detection system

    NASA Astrophysics Data System (ADS)

    Jiang, J.; Ma, G. M.; Luo, D. P.; Li, C. R.; Li, Q. M.; Wang, W.

    2014-02-01

    Damped AC voltages detection system (DAC) is a productive way to detect the faults in power cables. To solve the problems of large volume, complicated structure and electromagnetic interference in existing switches, this paper developed a compact solid state switch based on electromagnetic trigger, which is suitable for DAC test system. Synchronous electromagnetic trigger of 32 Insulated Gate Bipolar Transistors (IGBTs) in series was realized by the topological structure of single line based on pulse width modulation control technology. In this way, external extension was easily achieved. Electromagnetic trigger and resistor-capacitor-diode snubber circuit were optimized to reduce the switch turn-on time and circular layout. Epoxy encapsulating was chosen to enhance the level of partial discharge initial voltage (PDIV). The combination of synchronous trigger and power supply is proposed to reduce the switch volume. Moreover, we have overcome the drawback of the electromagnetic interference and improved the detection sensitivity of DAC by using capacitor storage energy to maintain IGBT gate driving voltage. The experimental results demonstrated that the solid-state switch, with compact size, whose turn-on time was less than 400 ns and PDIV was more than 65 kV, was able to meet the actual demands of 35 kV DAC test system.

  14. Partial Antiviral Activities Detection of Chicken Mx Jointing with Neuraminidase Gene (NA) against Newcastle Disease Virus

    PubMed Central

    Zhang, Yani; Fu, Dezhi; Chen, Hao; Zhang, Zhentao; Shi, Qingqing; Elsayed, Ahmed Kamel; Li, Bichun

    2013-01-01

    As an attempt to increase the resistance to Newcastle Disease Virus (NDV) and so further reduction of its risk on the poultry industry. This work aimed to build the eukaryotic gene co-expression plasmid of neuraminidase (NA) gene and myxo-virus resistance (Mx) and detect the gene expression in transfected mouse fibroblasts (NIH-3T3) cells, it is most important to investigate the influence of the recombinant plasmid on the chicken embryonic fibroblasts (CEF) cells. cDNA fragment of NA and mutant Mx gene were derived from pcDNA3.0-NA and pcDNA3.0-Mx plasmid via PCR, respectively, then NA and Mx cDNA fragment were inserted into the multiple cloning sites of pVITRO2 to generate the eukaryotic co-expression plasmid pVITRO2-Mx-NA. The recombinant plasmid was confirmed by restriction endonuclease treatment and sequencing, and it was transfected into the mouse fibroblasts (NIH-3T3) cells. The expression of genes in pVITRO2-Mx-NA were measured by RT-PCR and indirect immunofluorescence assay (IFA). The recombinant plasmid was transfected into CEF cells then RT-PCR and the micro-cell inhibition tests were used to test the antiviral activity for NDV. Our results showed that co-expression vector pVITRO2-Mx-NA was constructed successfully; the expression of Mx and NA could be detected in both NIH-3T3 and CEF cells. The recombinant proteins of Mx and NA protect CEF cells from NDV infection until after 72 h of incubation but the individually mutagenic Mx protein or NA protein protects CEF cells from NDV infection till 48 h post-infection, and co-transfection group decreased significantly NDV infection compared with single-gene transfection group (P<0. 05), indicating that Mx-NA jointing contributed to delaying the infection of NDV in single-cell level and the co-transfection of the jointed genes was more powerful than single one due to their synergistic effects. PMID:23977111

  15. Fixing the Shadows While Moving the Gnomon

    ERIC Educational Resources Information Center

    Gangui, Alejandro

    2015-01-01

    It is a common practice to fix a vertical gnomon and study the moving shadow cast by it. This shows our local solar time and gives us a hint regarding the season in which we perform the observation. The moving shadow can also tell us our latitude with high precision. In this paper we propose to exchange the roles and while keeping the shadows…

  16. Researching Shadow Education: Methodological Challenges and Directions

    ERIC Educational Resources Information Center

    Bray, Mark

    2010-01-01

    Research on shadow education has considerably increased in volume and has helped to improve understanding of the scale, nature, and implications of the phenomenon. However, the field is still in its infancy. Literature on shadow education reflects confusion over terms and parameters, and data suffer from challenges in securing evidence from actors…

  17. Shadow Attenuation With High Dynamic Range Images

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Shadow often interferes with accurate image analysis. To mitigate shadow effects in near-earth imagery (2 m above ground level), we created high dynamic range (HDR) nadir images and used them to measure grassland ground cover. HDR composites were created by merging three differentially-exposed image...

  18. Shadowing in Compton scattering on nuclei

    SciTech Connect

    Kopeliovich, B. Z.; Schmidt, Ivan; Siddikov, M.

    2010-05-01

    We evaluate the shadowing effect in deeply virtual and real Compton scattering on nuclei in the framework of the color dipole model. We rely on the soft photon wave function derived in the instanton vacuum model and employ the impact parameter dependent phenomenological elastic dipole amplitude. Both the effects of quark and the gluon shadowing are taken into account.

  19. Partial Least Squares Regression Can Aid in Detecting Differential Abundance of Multiple Features in Sets of Metagenomic Samples

    PubMed Central

    Libiger, Ondrej; Schork, Nicholas J.

    2015-01-01

    It is now feasible to examine the composition and diversity of microbial communities (i.e., “microbiomes”) that populate different human organs and orifices using DNA sequencing and related technologies. To explore the potential links between changes in microbial communities and various diseases in the human body, it is essential to test associations involving different species within and across microbiomes, environmental settings and disease states. Although a number of statistical techniques exist for carrying out relevant analyses, it is unclear which of these techniques exhibit the greatest statistical power to detect associations given the complexity of most microbiome datasets. We compared the statistical power of principal component regression, partial least squares regression, regularized regression, distance-based regression, Hill's diversity measures, and a modified test implemented in the popular and widely used microbiome analysis methodology “Metastats” across a wide range of simulated scenarios involving changes in feature abundance between two sets of metagenomic samples. For this purpose, simulation studies were used to change the abundance of microbial species in a real dataset from a published study examining human hands. Each technique was applied to the same data, and its ability to detect the simulated change in abundance was assessed. We hypothesized that a small subset of methods would outperform the rest in terms of the statistical power. Indeed, we found that the Metastats technique modified to accommodate multivariate analysis and partial least squares regression yielded high power under the models and data sets we studied. The statistical power of diversity measure-based tests, distance-based regression and regularized regression was significantly lower. Our results provide insight into powerful analysis strategies that utilize information on species counts from large microbiome data sets exhibiting skewed frequency distributions

  20. Partial Least Squares Regression Can Aid in Detecting Differential Abundance of Multiple Features in Sets of Metagenomic Samples.

    PubMed

    Libiger, Ondrej; Schork, Nicholas J

    2015-01-01

    It is now feasible to examine the composition and diversity of microbial communities (i.e., "microbiomes") that populate different human organs and orifices using DNA sequencing and related technologies. To explore the potential links between changes in microbial communities and various diseases in the human body, it is essential to test associations involving different species within and across microbiomes, environmental settings and disease states. Although a number of statistical techniques exist for carrying out relevant analyses, it is unclear which of these techniques exhibit the greatest statistical power to detect associations given the complexity of most microbiome datasets. We compared the statistical power of principal component regression, partial least squares regression, regularized regression, distance-based regression, Hill's diversity measures, and a modified test implemented in the popular and widely used microbiome analysis methodology "Metastats" across a wide range of simulated scenarios involving changes in feature abundance between two sets of metagenomic samples. For this purpose, simulation studies were used to change the abundance of microbial species in a real dataset from a published study examining human hands. Each technique was applied to the same data, and its ability to detect the simulated change in abundance was assessed. We hypothesized that a small subset of methods would outperform the rest in terms of the statistical power. Indeed, we found that the Metastats technique modified to accommodate multivariate analysis and partial least squares regression yielded high power under the models and data sets we studied. The statistical power of diversity measure-based tests, distance-based regression and regularized regression was significantly lower. Our results provide insight into powerful analysis strategies that utilize information on species counts from large microbiome data sets exhibiting skewed frequency distributions obtained

  1. Shadowing in deep inelastic muon scattering from nuclear targets

    NASA Astrophysics Data System (ADS)

    Arneodo, M.; Arvidson, A.; Aubert, J. J.; Badelek, B.; Beaufays, J.; Bee, C. P.; Benchouk, C.; Berghoff, G.; Bird, I.; Blum, D.; Böhm, E.; De Bouard, X.; Brasse, F. W.; Braun, H.; Broll, C.; Brown, S.; Brück, H.; Brüll, A.; Calen, H.; Chima, J. S.; Ciborowski, J.; Clifft, R.; Coignet, G.; Combley, F.; Coughlan, J.; D'Agostini, G.; Dahlgren, S.; Dengler, F.; Derado, I.; Dreyer, T.; Drees, J.; Drobnitzki, M.; Düren, M.; Eckardt, V.; Edwards, A.; Edwards, M.; Ernst, T.; Eszes, G.; Favier, J.; Ferrero, M. I.; Figiel, J.; Foster, J.; Ftacnik, J.; Gabathuler, E.; Gajewski, J.; Gamet, R.; Geddes, N.; Grafström, P.; Gustafsson, L.; Haas, J.; Hagberg, E.; Hasert, F. J.; Hayman, P.; Heusse, P.; Jaffré, M.; Jacholkowska, A.; Janata, F.; Jancso, G.; Johnson, A. S.; Kabuss, E. M.; Kaiser, R.; Kellner, G.; Krüger, A.; Krüger, J.; Kullander, S.; Landgraf, U.; Lanske, D.; Loken, J.; Long, K.; Maire, M.; Malecki, P.; Manz, A.; Maselli, S.; Mohr, W.; Montanet, F.; Montgomery, H. E.; Nagy, E.; Nassalski, J.; Norton, P. R.; Oakham, F. G.; Osborne, A. M.; Pascaud, C.; Pawlik, B.; Payre, P.; Peroni, C.; Peschel, H.; Pessard, H.; Pettingale, J.; Pietrzyk, B.; Pietrzyk, U.; Pönsgen, B.; Pötsch, M.; Renton, P.; Ribarics, P.; Rith, K.; Rondio, E.; Sandacz, A.; Scheer, M.; Schlagböhmer, A.; Schiemann, H.; Schmitz, N.; Schneegans, M.; Scholz, M.; Schröder, T.; Schultze, K.; Seidel, A.; Sloan, T.; Stier, H. E.; Studt, M.; Taylor, G. N.; Thénard, J. M.; Thompson, J. C.; De La Torre, A.; Toth, J.; Urban, L.; Urban, L.; Wallucks, W.; Whalley, M.; Wheeler, S.; Williams, W. S. C.; Wimpenny, S. J.; Windmolders, R.; Wolf, G.; Ziemons, K.; European Muon Collaboration

    1988-09-01

    Results are presented on the ratio of the inelastic muon-nucleus cross section per nucleon for carbon and calcium relative to that for deuterium. The measurements were made in the kinematic range of low x (0.003-0.1) and low Q2 (0.3-3.2 GeV 2) at an incident muon energy of 280 GeV. The calcium to deuterium ratio shows a significant x dependence which is interpreted as a shadowing effect. No strong Q2 dependence is observed. This suggests that the effect is due at least partially to parton interactions within the nucleus.

  2. Detection and partial characterization of an inhibitor of plasminogen activator in human platelets.

    PubMed Central

    Erickson, L A; Ginsberg, M H; Loskutoff, D J

    1984-01-01

    In this study, we demonstrate the presence of a previously undescribed fibrinolytic inhibitor in human serum. It has an apparent molecular weight of 50,000 and is not detected in serum derived from platelet-poor plasma, suggesting that it originates from platelets. This conclusion is supported by a number of observations. For example, extracts of washed, gel-filtered human platelets contain an inhibitor of similar activity and size, and physiological concentrations of thrombin induce its release from the platelets. Moreover, the kinetics and dose dependency of this release are similar to those observed for the release of platelet factor 4, and the release of both molecules is blocked by pretreating the platelets with prostaglandin E1 and theophylline. Mixing experiments, which were devised to investigate the specificity of the inhibitor, showed that the fibrinolytic activity initiated by both urokinase and tissue-type plasminogen activator was blocked by platelet releasate in a dose-dependent manner. In both cases, the amount of inhibition increased when the releasates were preincubated with the purified activators, indicating a direct interaction between the activators and an inhibitor(s). The inhibitory activity was removed by preincubating the releasates with antiserum prepared against an antiactivator purified from cultured bovine aortic endothelial cells. These results indicate that platelets contain an inhibitor which is released by thrombin, inhibits both urokinase and tissue-type plasminogen activator, and is immunologically similar to an inhibitor produced by endothelial cells. This molecule may represent a new class of inhibitors, the antiactivators, which function together with alpha 2-antiplasmin to regulate the fibrinolytic system of the blood. Its release from platelets by thrombin may protect the growing thrombus against premature dissolution initiated by plasminogen activators released by the endothelium. Images PMID:6434594

  3. Shadow of rotating regular black holes

    NASA Astrophysics Data System (ADS)

    Abdujabbarov, Ahmadjon; Amir, Muhammed; Ahmedov, Bobomurat; Ghosh, Sushant G.

    2016-05-01

    We study the shadows cast by the different types of rotating regular black holes viz. Ayón-Beato-García (ABG), Hayward, and Bardeen. These black holes have in addition to the total mass (M ) and rotation parameter (a ), different parameters as electric charge (Q ), deviation parameter (g ), and magnetic charge (g*). Interestingly, the size of the shadow is affected by these parameters in addition to the rotation parameter. We found that the radius of the shadow in each case decreases monotonically, and the distortion parameter increases when the values of these parameters increase. A comparison with the standard Kerr case is also investigated. We have also studied the influence of the plasma environment around regular black holes to discuss its shadow. The presence of the plasma affects the apparent size of the regular black hole's shadow to be increased due to two effects: (i) gravitational redshift of the photons and (ii) radial dependence of plasma density.

  4. Shadow Enhancers Are Pervasive Features of Developmental Regulatory Networks

    PubMed Central

    Cannavò, Enrico; Khoueiry, Pierre; Garfield, David A.; Geeleher, Paul; Zichner, Thomas; Gustafson, E. Hilary; Ciglar, Lucia; Korbel, Jan O.; Furlong, Eileen E.M.

    2016-01-01

    Summary Embryogenesis is remarkably robust to segregating mutations and environmental variation; under a range of conditions, embryos of a given species develop into stereotypically patterned organisms. Such robustness is thought to be conferred, in part, through elements within regulatory networks that perform similar, redundant tasks. Redundant enhancers (or “shadow” enhancers), for example, can confer precision and robustness to gene expression, at least at individual, well-studied loci. However, the extent to which enhancer redundancy exists and can thereby have a major impact on developmental robustness remains unknown. Here, we systematically assessed this, identifying over 1,000 predicted shadow enhancers during Drosophila mesoderm development. The activity of 23 elements, associated with five genes, was examined in transgenic embryos, while natural structural variation among individuals was used to assess their ability to buffer against genetic variation. Our results reveal three clear properties of enhancer redundancy within developmental systems. First, it is much more pervasive than previously anticipated, with 64% of loci examined having shadow enhancers. Their spatial redundancy is often partial in nature, while the non-overlapping function may explain why these enhancers are maintained within a population. Second, over 70% of loci do not follow the simple situation of having only two shadow enhancers—often there are three (rols), four (CadN and ade5), or five (Traf1), at least one of which can be deleted with no obvious phenotypic effects. Third, although shadow enhancers can buffer variation, patterns of segregating variation suggest that they play a more complex role in development than generally considered. PMID:26687625

  5. Projectors, shadows, and conformal blocks

    NASA Astrophysics Data System (ADS)

    Simmons-Duffin, David

    2014-04-01

    We introduce a method for computing conformal blocks of operators in arbitrary Lorentz representations in any spacetime dimension, making it possible to apply bootstrap techniques to operators with spin. The key idea is to implement the "shadow formalism" of Ferrara, Gatto, Grillo, and Parisi in a setting where conformal invariance is manifest. Conformal blocks in d-dimensions can be expressed as integrals over the projective null-cone in the "embedding space" d+1,1. Taking care with their analytic structure, these integrals can be evaluated in great generality, reducing the computation of conformal blocks to a bookkeeping exercise. To facilitate calculations in four-dimensional CFTs, we introduce techniques for writing down conformally-invariant correlators using auxiliary twistor variables, and demonstrate their use in some simple examples.

  6. ASI/MET shadow & airbags

    NASA Technical Reports Server (NTRS)

    1997-01-01

    A shadow of the Atmospheric Structure Instrument/Meteorology Package (ASI/MET) has been cast on a rock at right in this image, taken by the Imager for Mars Pathfinder (IMP) on Sol 4. The instrument appears in two different sections due to image parallax. The ASI/MET is an engineering subsytem that acquired atmospheric data during Pathfinder's descent, and will continue to get more data through the entire landed mission. Portions of a lander petal and deflated airbag are visible, in addition to several rocks of varying sizes in the distance.

    Mars Pathfinder was developed and managed by the Jet Propulsion Laboratory (JPL) for the National Aeronautics and Space Administration. JPL is an operating division of the California Institute of Technology (Caltech). The IMP was developed by the University of Arizona Lunar and Planetary Laboratory under contract to JPL. Peter Smith is the Principal Investigator.

  7. A new partial volume segmentation approach to extract bladder wall for computer-aided detection in virtual cystoscopy

    NASA Astrophysics Data System (ADS)

    Li, Lihong; Wang, Zigang; Li, Xiang; Wei, Xinzhou; Adler, Howard L.; Huang, Wei; Rizvi, Syed A.; Meng, Hong; Harrington, Donald P.; Liang, Zhengrong

    2004-04-01

    We propose a new partial volume (PV) segmentation scheme to extract bladder wall for computer aided detection (CAD) of bladder lesions using multispectral MR images. Compared with CT images, MR images provide not only a better tissue contrast between bladder wall and bladder lumen, but also the multispectral information. As multispectral images are spatially registered over three-dimensional space, information extracted from them is more valuable than that extracted from each image individually. Furthermore, the intrinsic T1 and T2 contrast of the urine against the bladder wall eliminates the invasive air insufflation procedure. Because the earliest stages of bladder lesion growth tend to develop gradually and migrate slowly from the mucosa into the bladder wall, our proposed PV algorithm quantifies images as percentages of tissues inside each voxel. It preserves both morphology and texture information and provides tissue growth tendency in addition to the anatomical structure. Our CAD system utilizes a multi-scan protocol on dual (full and empty of urine) states of the bladder to extract both geometrical and texture information. Moreover, multi-scan of transverse and coronal MR images eliminates motion artifacts. Experimental results indicate that the presented scheme is feasible towards mass screening and lesion detection for virtual cystoscopy (VC).

  8. A new sparse design method on phased array-based acoustic emission sensor for partial discharge detection

    NASA Astrophysics Data System (ADS)

    Xie, Qing; Cheng, Shuyi; Lü, Fangcheng; Li, Yanqing

    2014-03-01

    The acoustic detecting performance of a partial discharge (PD) ultrasonic sensor array can be improved by increasing the number of array elements. However, it will increase the complexity and cost of the PD detection system. Therefore, a sparse sensor with an optimization design can be chosen to ensure good acoustic performance. In this paper, first, a quantitative method is proposed for evaluating the acoustic performance of a square PD ultrasonic array sensor. Second, a method of sparse design is presented to combine the evaluation method with the chaotic monkey algorithm. Third, an optimal sparse structure of a 3 × 3 square PD ultrasonic array sensor is deduced. It is found that, under different sparseness and sparse structure, the main beam width of the directivity function shows a small variation, while the sidelobe amplitude shows a bigger variation. For a specific sparseness, the acoustic performance under the optimal sparse structure is close to that using a full array. Finally, some simulations based on the above method show that, for certain sparseness, the sensor with the optimal sparse structure exhibits superior positioning accuracy compared to that with a stochastic one. The sensor array structure may be chosen according to the actual requirements for an actual engineering application.

  9. Shadows, currents, and AdS fields

    SciTech Connect

    Metsaev, R. R.

    2008-11-15

    Conformal totally symmetric arbitrary spin currents and shadow fields in flat space-time of dimension greater than or equal to four are studied. A gauge invariant formulation for such currents and shadow fields is developed. Gauge symmetries are realized by involving the Stueckelberg fields. A realization of global conformal boost symmetries is obtained. Gauge invariant differential constraints for currents and shadow fields are obtained. AdS/CFT correspondence for currents and shadow fields and the respective normalizable and non-normalizable solutions of massless totally symmetric arbitrary spin AdS fields are studied. The bulk fields are considered in a modified de Donder gauge that leads to decoupled equations of motion. We demonstrate that leftover on shell gauge symmetries of bulk fields correspond to gauge symmetries of boundary currents and shadow fields, while the modified de Donder gauge conditions for bulk fields correspond to differential constraints for boundary conformal currents and shadow fields. Breaking conformal symmetries, we find interrelations between the gauge invariant formulation of the currents and shadow fields, and the gauge invariant formulation of massive fields.

  10. Fast shadow profiler and its applications

    NASA Astrophysics Data System (ADS)

    Glaeser, Georg; Groeller, Eduard

    1998-02-01

    'Shadow profiling' measures shadow durations on an arbitrary scene during several hours of a specific day or even several weeks or months. The result is to be displayed visually. We shortly discuss already known techniques like simplified radiosity or discontinuity meshing with regard to their suitability for this problem. Due to various drawbacks of these techniques, we present our won approach. Especially a pixel-oriented version works very efficiently in connection with fast polygon-oriented shadow algorithms. It can be applied to architectural design, and it can also be used in computer graphics for the computation-inexpensive simulation of complex light sources.

  11. Hands-On Science. Bright Ideas for Teaching About Shadows.

    ERIC Educational Resources Information Center

    Kepler, Lynne

    1997-01-01

    Presents an elementary level hands-on science activity designed to teach students about shadows. The activity helps students draw conclusions about shadows by experimenting with different materials and determining which will make a shadow. A sidebar explains what a shadow is and offers further resources. (SM)

  12. Observation in the MINOS far detector of the shadowing of cosmic rays by the sun and moon

    SciTech Connect

    Adamson, P.; Andreopoulos, C.; Ayres, D.S.; Backhouse, C.; Barr, G.; Barrett, W.L.; Bishai, M.; Blake, A.; Bock, B.; Bock, G.J.; Boehnlein, D.J.; /Fermilab /Fermilab

    2010-08-01

    The shadowing of cosmic ray primaries by the the moon and sun was observed by the MINOS far detector at a depth of 2070 mwe using 83.54 million cosmic ray muons accumulated over 1857.91 live-days. The shadow of the moon was detected at the 5.6 {sigma} level and the shadow of the sun at the 3.8 {sigma} level using a log-likelihood search in celestial coordinates. The moon shadow was used to quantify the absolute astrophysical pointing of the detector to be 0.17 {+-} 0.12{sup o}. Hints of Interplanetary Magnetic Field effects were observed in both the sun and moon shadow.

  13. Observation in the MINOS far detector of the shadowing of cosmic rays by the sun and moon

    SciTech Connect

    Jaffe, D.E.; Bishai, M.; Diwan, M.V.; Ling, J.; Viren, B.; Whitehead, L.,.

    2010-10-10

    The shadowing of cosmic ray primaries by the moon and sun was observed by the MINOS far detector at a depth of 2070 mwe using 83.54 million cosmic ray muons accumulated over 1857.91 live-days. The shadow of the moon was detected at the 5.6 {sigma} level and the shadow of the sun at the 3.8 {sigma} level using a log-likelihood search in celestial coordinates. The moon shadow was used to quantify the absolute astrophysical pointing of the detector to be 0.17 {+-} 0.12{sup o}. Hints of interplanetary magnetic field effects were observed in both the sun and moon shadow.

  14. Raman spectroscopy for clinical-level detection of heparin in serum by partial least-squares analysis

    NASA Astrophysics Data System (ADS)

    Monfared, Ali Momenpour T.; Tiwari, Vidhu S.; Tripathi, Markandey M.; Anis, Hanan

    2013-02-01

    Heparin is the most widely used anti-coagulant for the prevention of blood clots in patients undergoing certain types of surgeries including open heart surgeries and dialysis. The precise monitoring of heparin amount in patients' blood is crucial for reducing the morbidity and mortality in surgical environments. Based upon these considerations, we have used Raman spectroscopy in conjunction with partial least squares (PLS) analysis to measure heparin concentration at clinical level which is less than 10 United States Pharmacopeia (USP) in serum. The PLS calibration model was constructed from the Raman spectra of different concentrations of heparin in serum. It showed a high coefficient of determination (R2>0.91) between the spectral data and heparin level in serum along with a low root mean square error of prediction ˜4 USP/ml. It enabled the detection of extremely low concentrations of heparin in serum (˜8 USP/ml) as desirable in clinical environment. The proposed optical method has the potential of being implemented as the point-of-care testing procedure during surgeries, where the interest is to rapidly monitor low concentrations of heparin in patient's blood.

  15. Automated 3D detection and classification of Giardia lamblia cysts using digital holographic microscopy with partially coherent source

    NASA Astrophysics Data System (ADS)

    El Mallahi, A.; Detavernier, A.; Yourassowsky, C.; Dubois, F.

    2012-06-01

    Over the past century, monitoring of Giardia lamblia became a matter of concern for all drinking water suppliers worldwide. Indeed, this parasitic flagellated protozoan is responsible for giardiasis, a widespread diarrhoeal disease (200 million symptomatic individuals) that can lead immunocompromised individuals to death. The major difficulty raised by Giardia lamblia's cyst, its vegetative transmission form, is its ability to survive for long periods in harsh environments, including the chlorine concentrations and treatment duration used traditionally in water disinfection. Currently, there is a need for a reliable, inexpensive, and easy-to-use sensor for the identification and quantification of cysts in the incoming water. For this purpose, we investigated the use of a digital holographic microscope working with partially coherent spatial illumination that reduces the coherent noise. Digital holography allows one to numerically investigate a volume by refocusing the different plane of depth of a hologram. In this paper, we perform an automated 3D analysis that computes the complex amplitude of each hologram, detects all the particles present in the whole volume given by one hologram and refocuses them if there are out of focus using a refocusing criterion based on the integrated complex amplitude modulus and we obtain the (x,y,z) coordinates of each particle. Then the segmentation of the particles is processed and a set of morphological and textures features characteristic to Giardia lamblia cysts is computed in order to classify each particles in the right classes.

  16. Initial tests of a new phantom for investigation of spatial resolution, partial volume effect and detectability in nuclear medicine tomography

    NASA Astrophysics Data System (ADS)

    Söderberg, M.; Engeland, U.; Mattsson, S.; Ebel, G.; Leide-Svegborn, S.

    2011-09-01

    A new phantom has been designed that can provide simultaneously different target to background activity ratios with a linearly changing diameter of lesions. The purpose of the study was to describe and perform initial measurements with the phantom aimed to characterize different nuclear medicine tomographic systems and reconstruction algorithms in their performance and behaviour concerning partial volume effect (PVE) and detectability by varying the acquisition parameters and the count statistics. The phantom has an external vessel whose outline is half-cylindrical and allows it to be incorporated into an anthropomorphic thorax phantom. The phantom itself contains 16 fillable cones with an inner diameter linearly decreasing from 16 mm to 2 mm and a wall thickness of 1 mm acrylic glass. They as well as the outer vessel were separately filled with 99mTc- and 18F-solutions respectively of different activity concentrations. The phantom was easy to fill and air bubbles could easily be avoided. Images taken using a SPECT/CT and a PET/CT system are presented as well as evaluations of PVE. The new phantom seems to be useful for comparison and optimisation of different acquisition and reconstruction parameters in nuclear medicine tomographic studies and for comparisons between various tomographic units.

  17. Shadow of noncommutative geometry inspired black hole

    NASA Astrophysics Data System (ADS)

    Wei, Shao-Wen; Cheng, Peng; Zhong, Yi; Zhou, Xiang-Nan

    2015-08-01

    In this paper, the shadow casted by the rotating black hole inspired by noncommutative geometry is investigated. In addition to the dimensionless spin parameter a/M0 with M0 black hole mass and inclination angle i, the dimensionless noncommutative parameter √vartheta/M0 is also found to affect the shape of the black hole shadow. The result shows that the size of the shadow slightly decreases with the parameter √vartheta/M0, while the distortion increases with it. Compared to the Kerr black hole, the parameter √vartheta/M0 increases the deformation of the shadow. This may offer a way to distinguish noncommutative geometry inspired black hole from Kerr one via astronomical instruments in the near future.

  18. Integrating shadow casting methodology and thermal simulation

    SciTech Connect

    Malkawi, A.; Jabi, W.

    1996-10-01

    This paper describes an experiment that integrates shadow casting methodology and thermal simulation algorithms developed by the authors. The 3D shadow procedures use a polyhedral representation of solids within a Cartesian space that allows for accurate casting of shadows. The algorithm is also capable of calculating surface areas of polygonal shadows of any arbitrary shape and size. The thermal simulation algorithms--using the Transfer Function Method (TFM)--incorporate the shaded area calculations to better predict solar heat gain from glazing based on transmitted, absorbed, and conducted cooling loads. The paper describes the use of a 3D computer model to illustrate the impact of the pattern and area of shading on the visual and thermal properties of building apertures. The paper discusses the objectives of this experiment, the algorithms used, and their integration. Conclusions and findings are drawn.

  19. Real-time simulation of thermal shadows with EMIT

    NASA Astrophysics Data System (ADS)

    Klein, Andreas; Oberhofer, Stefan; Schätz, Peter; Nischwitz, Alfred; Obermeier, Paul

    2016-05-01

    Modern missile systems use infrared imaging for tracking or target detection algorithms. The development and validation processes of these missile systems need high fidelity simulations capable of stimulating the sensors in real-time with infrared image sequences from a synthetic 3D environment. The Extensible Multispectral Image Generation Toolset (EMIT) is a modular software library developed at MBDA Germany for the generation of physics-based infrared images in real-time. EMIT is able to render radiance images in full 32-bit floating point precision using state of the art computer graphics cards and advanced shader programs. An important functionality of an infrared image generation toolset is the simulation of thermal shadows as these may cause matching errors in tracking algorithms. However, for real-time simulations, such as hardware in the loop simulations (HWIL) of infrared seekers, thermal shadows are often neglected or precomputed as they require a thermal balance calculation in four-dimensions (3D geometry in one-dimensional time up to several hours in the past). In this paper we will show the novel real-time thermal simulation of EMIT. Our thermal simulation is capable of simulating thermal effects in real-time environments, such as thermal shadows resulting from the occlusion of direct and indirect irradiance. We conclude our paper with the practical use of EMIT in a missile HWIL simulation.

  20. Leading twist nuclear shadowing phenomena in hard processes with nuclei

    SciTech Connect

    L. Franfurt; Guzey, V.; Strikman, M.

    2012-01-08

    We present and discuss the theory and phenomenology of the leading twist theory of nuclear shadowing which is based on the combination of the generalization of Gribov-Glauber theory, QCD factorization theorems, and HERA QCD analysis of diffraction in lepton-proton deep inelastic scattering (DIS). We apply this technique for the analysis of a wide range of hard processes with nuclei-inclusive DIS on deuterons, medium-range and heavy nuclei, coherent and incoherent diffractive DIS with nuclei, and hard diffraction in proton-nucleus scattering - and make predictions for the effect of nuclear shadowing in the corresponding sea quark and gluon parton distributions. We also analyze the role of the leading twist nuclear shadowing in generalized parton distributions in nuclei and certain characteristics of final states in nuclear DIS. We discuss the limits of applicability of the leading twist approximation for small x scattering off nuclei and the onset of the black disk regime and methods of detecting it. It will be possible to check many of our predictions in the near future in the studies of the ultraperipheral collisions at the Large Hadron Collider (LHC). Further checks will be possible in pA collisions at the LHC and forward hadron production at Relativistic Heavy Ion Collider (RHIC). As a result, detailed tests will be possible at an Electon-Ion Collider (EIC) in USA and at the Large Hadron-Electron Collider (LHeC) at CERN.

  1. Leading twist nuclear shadowing phenomena in hard processes with nuclei

    DOE PAGESBeta

    L. Franfurt; Guzey, V.; Strikman, M.

    2012-01-08

    We present and discuss the theory and phenomenology of the leading twist theory of nuclear shadowing which is based on the combination of the generalization of Gribov-Glauber theory, QCD factorization theorems, and HERA QCD analysis of diffraction in lepton-proton deep inelastic scattering (DIS). We apply this technique for the analysis of a wide range of hard processes with nuclei-inclusive DIS on deuterons, medium-range and heavy nuclei, coherent and incoherent diffractive DIS with nuclei, and hard diffraction in proton-nucleus scattering - and make predictions for the effect of nuclear shadowing in the corresponding sea quark and gluon parton distributions. We alsomore » analyze the role of the leading twist nuclear shadowing in generalized parton distributions in nuclei and certain characteristics of final states in nuclear DIS. We discuss the limits of applicability of the leading twist approximation for small x scattering off nuclei and the onset of the black disk regime and methods of detecting it. It will be possible to check many of our predictions in the near future in the studies of the ultraperipheral collisions at the Large Hadron Collider (LHC). Further checks will be possible in pA collisions at the LHC and forward hadron production at Relativistic Heavy Ion Collider (RHIC). As a result, detailed tests will be possible at an Electon-Ion Collider (EIC) in USA and at the Large Hadron-Electron Collider (LHeC) at CERN.« less

  2. The shadowing experience for nursing students.

    PubMed

    Eades, Jackie; Hill, Karen; Craig, Jennifer

    The shadowing scheme supports nursing students in learning how to manage and identify the characteristics of good leadership. Derby Hospitals NHS Foundation Trust and the University of Nottingham offered nursing students the opportunity to shadow service leaders and managers during their final semester. This initiative promotes an effective service, takes account of students' needs and interests and supports the government's modernisation agenda and the NHS Plan (Department of Health (DH) 2000). PMID:16350502

  3. Amplification of dust loading in Martian dust devils by self-shadowing

    NASA Astrophysics Data System (ADS)

    Kuepper, M.; Wurm, G.

    2016-08-01

    Insolation of the Martian soil leads to a sub-surface overpressure due to thermal creep gas flow. This could support particle entrainment into the atmosphere. Short time shadowing e.g. by the traverse of a larger dust devil would enhance this effect. We find in microgravity experiments that mass ejection rates are increased by a factor of 10 for several seconds if a light source of 12.6 kW/m2 is turned off. Scaled to Mars this implies that self-shadowing of a partially opaque dust devil might lead to a strongly amplified flux of lifted material. We therefore suggest that self-shadowing might be a mechanism on Mars to increase the total dust loading of a dust devil and keep it self-sustained.

  4. Being the shadow: witnessing schizophrenia.

    PubMed

    Diedrich, Lisa

    2010-06-01

    This essay discusses Susan Smiley's documentary film, Out of the Shadow (2004), and Tina Kotulski's memoir, Saving Millie: A Daughter's Story of Surviving Her Mother's Schizophrenia, as filmic and narrative treatments of their mother's schizophrenia. Mildred Smiley, and her diagnosis of and treatment for schizophrenia, is at the center of both her daughters' treatments of mental illness, and in these texts, all three become witnesses to the multiple experiences of mental illness and the multiple events of psychiatric power. As I will argue, these two texts are treatments of schizophrenia that both see and don't see Mildred Smiley's experience of mental illness. Through these texts, we--viewer and reader--are asked to look again, or to look for the first time, at mental illness, and we are positioned as having the agency to look or look away. As we look and try to make sense of what we see (and don't see), we too participate in the production of mental illness as a category of analysis. PMID:20127152

  5. Shapes of rotating nonsingular black hole shadows

    NASA Astrophysics Data System (ADS)

    Amir, Muhammed; Ghosh, Sushant G.

    2016-07-01

    It is believed that curvature singularities are a creation of general relativity and, hence, in the absence of a quantum gravity, models of nonsingular black holes have received significant attention. We study the shadow (apparent shape), an optical appearance because of its strong gravitational field, cast by a nonsingular black hole which is characterized by three parameters, i.e., mass (M ), spin (a ), and a deviation parameter (k ). The nonsingular black hole under consideration is a generalization of the Kerr black hole that can be recognized asymptotically (r ≫k ,k >0 ) explicitly as the Kerr-Newman black hole, and in the limit k →0 as the Kerr black hole. It turns out that the shadow of a nonsingular black hole is a dark zone covered by a deformed circle. Interestingly, it is seen that the shadow of a black hole is affected due to the parameter k . Indeed, for a given a , the size of a shadow reduces as the parameter k increases, and the shadow becomes more distorted as we increase the value of the parameter k when compared with the analogous Kerr black hole shadow. We also investigate, in detail, how the ergoregion of a black hole is changed due to the deviation parameter k .

  6. Exposing photo manipulation using geometry and shadows

    NASA Astrophysics Data System (ADS)

    Zheng, Jiangbin; Song, Xuemei; Ren, Jinchang; Zhu, Tingge

    2014-04-01

    It is increasingly easier to manipulate digital images by the sophisticated photo editing software. Often visual inspection cannot definitively distinguish manipulation from authentic images. This paper introduces a forensic technique that focuses on geometric and shadow color inconsistencies which arise when fake objects with shadows are inserted into an image or an object with its shadow in the image are modified. This paper analyzes three underlying geometric relations and shadow color characteristic constrains that occur in image scene. In particular, (i) explore the property of vanishing point in linear perspective project, and evaluate the geometric consistent level of the image based on the uncertain degree of vanishing point;(ii) analyze the relation between illuminated object and its cast shadow which are modeled by the planar homology and use this constrain to estimate the image's geometric consistent level;(iii) locate tempered region by measure the K-L divergence between shadow pairs. Visually plausible forgery images demonstrate the performance of our proposed method.

  7. Teaching in the Shadow: Operators of Small Shadow Education Institutions in Japan

    ERIC Educational Resources Information Center

    Dierkes, Julian

    2010-01-01

    The shadow education sector plays a centrally important role in the Japanese education system. Advocates of Japanese shadow education institutions, or "juku", claim that the pedagogy employed in these schools leads to superior results compared to teaching methods used in conventional schools. The lack of value-added testing of juku results…

  8. Reading in the Shadows: Extending Literacy Skills through Shadow-Puppet Theater

    ERIC Educational Resources Information Center

    Peck, Sharon M.; Virkler, Aubre J.

    2006-01-01

    This article explores the impact of integrating literacy and social studies instruction through Readers Theatre and shadow puppetry. During an inquiry-based social studies unit on national symbols, second graders created shadow-puppet performances. During the literacy block students worked in small groups to research a topic, develop a script,…

  9. Applying target shadow models for SAR ATR

    NASA Astrophysics Data System (ADS)

    Papson, Scott; Narayanan, Ram M.

    2007-04-01

    Recent work has suggested that target shadows in synthetic aperture radar (SAR) images can be used effectively to aid in target classification. The method outlined in this paper has four steps - segmentation, representation, modeling, and selection. Segmentation is the process by which a smooth, background-free representation of the target's shadow is extracted from an image chip. A chain code technique is then used to represent the shadow boundary. Hidden Markov modeling is applied to sets of chain codes for multiple targets to create a suitable bank of target representations. Finally, an ensemble framework is proposed for classification. The proposed model selection process searches for an optimal ensemble of models based on various target model configurations. A five target subset of the MSTAR database is used for testing. Since the shadow is a back-projection of the target profile, some aspect angles will contain more discriminatory information then others. Therefore, performance is investigated as a function of aspect angle. Additionally, the case of multiple target looks is considered. The capability of the shadow-only classifier to enhance more traditional classification techniques is examined.

  10. An Efficient and Robust Moving Shadow Removal Algorithm and Its Applications in ITS

    NASA Astrophysics Data System (ADS)

    Lin, Chin-Teng; Yang, Chien-Ting; Shou, Yu-Wen; Shen, Tzu-Kuei

    2010-12-01

    We propose an efficient algorithm for removing shadows of moving vehicles caused by non-uniform distributions of light reflections in the daytime. This paper presents a brand-new and complete structure in feature combination as well as analysis for orientating and labeling moving shadows so as to extract the defined objects in foregrounds more easily in each snapshot of the original files of videos which are acquired in the real traffic situations. Moreover, we make use of Gaussian Mixture Model (GMM) for background removal and detection of moving shadows in our tested images, and define two indices for characterizing non-shadowed regions where one indicates the characteristics of lines and the other index can be characterized by the information in gray scales of images which helps us to build a newly defined set of darkening ratios (modified darkening factors) based on Gaussian models. To prove the effectiveness of our moving shadow algorithm, we carry it out with a practical application of traffic flow detection in ITS (Intelligent Transportation System)—vehicle counting. Our algorithm shows the faster processing speed, 13.84 ms/frame, and can improve the accuracy rate in 4% ~ 10% for our three tested videos in the experimental results of vehicle counting.

  11. Microbial contamination of cosmetics and personal care items in Egypt--eye shadows, mascaras and face creams.

    PubMed

    Abdelaziz, A A; Ashour, M S; Hefni, H; el-Tayeb, O M

    1989-02-01

    We examined a total of 150 samples, including 27 eye shadows, 27 mascaras and 96 face creams, for their microbial contents. Mascaras were generally more contaminated than eye shadows. More than 75% of the examined eye shadows contained fewer than 100 c.f.u./g aerobic bacterial count compared to 63% of the mascaras examined. Viable bacteria were not recovered from 61% and 48% of the eye shadows and mascaras respectively. While 4% of the eye shadows were heavily contaminated (contained more than 10(4) c.f.u./g), 15% of the mascaras were as heavily contaminated (with more than 10(4) c.f.u./ml of bacteria). Face creams were generally more heavily contaminated than eye shadows and mascaras. More than 70% of the examined creams contained more than 100 c.f.u./g of bacteria compared to 23% and 37% of eye shadows and mascaras respectively. Only 5% of the face creams were heavily contaminated. However, 27% of the creams were contaminated with more than 10(3)-10(4) c.f.u./g of bacteria compared to none in this range for both eye shadows and mascaras. Qualitative tests for detection of hazardous bacteria showed that none of the eye shadows were contaminated with any of those micro-organisms. Out of nine items of a specific brand of mascara, three isolates of Pseudomonas aeruginosa, one isolate of Citrobacter freundii and one isolate of Klebsiella pneumonia were detected. Among the creams, two brands showed the highest contamination levels with more than 85% of the tested samples containing more than 10(3) c.f.u./g fungi and at least 10(4) c.f.u./g bacteria.(ABSTRACT TRUNCATED AT 250 WORDS) PMID:2921299

  12. The role of different magnetotelluric tensor relationships in detecting partial melt in continental collision zones: Results from synthetic models and real data

    NASA Astrophysics Data System (ADS)

    Campanya i Llovet, J.; Ledo, J.; Jones, A. G.; Queralt, P.; Marcuello, A.; Liesa, M.; Muñoz, J.

    2013-12-01

    Three magnetotelluric (MT) tensor relationships - the single-station MT impedance tensor, the single-station vertical geomagnetic transfer function (GTF) and the multiple-station horizontal geomagnetic transfer function (HGTF) - were investigated for their role in detecting the presence of partial melting in continental collision zones. Synthetic models based on previous studies were used to characterize the sensitivity of each tensor relationship constraining the presence of partial melt at lower-crustal and upper-mantle depths. From the MT response of the synthetic models, each type of data has been inverted separately and jointly with the others, thus determining the properties and advantages of each when modeling the subsurface. Non-linear sensitivity tests have been carried out to determine the resolution that can be expected when constraining electrical resistivity anomalies associated with the presence of partial melt. The electrical resistivity anomalies associated with different amounts of partial melt were calculated using the two phases of Archie's law and Hashin Shtrikman extremal bounds. The results have been compared with the sensitivity of the MT tensor relationships, thus determining the resolution that can be expected in the detection of partial melt at lower-crustal and upper-mantle depths. Equivalent analyses have been performed using real MT data from a survey carried out in the Pyrenees. The data comprise a total of 82 broadband MT sites and 29 long period MT sites distributed along four profiles across the Pyrenean mountain range between the Atlantic Ocean and the Mediterranean Sea. The results show the presence of a low-electrical-resistivity structure that has been associated with partial melting of the Iberian subducted lower crust. This anomaly has been constrained below three of the MT profiles but seems to be absent below the Eastern Pyrenees MT profile. A non-linear sensitivity tests was undertaken to ensure that the absence of this

  13. Designing catalytic nanomotors by dynamic shadowing growth.

    PubMed

    He, Yuping; Wu, Jinsong; Zhao, Yiping

    2007-05-01

    Using a geometric shadowing effect, a thin catalyst layer can be coated asymmetrically on the side of a nanorod backbone. Combining with substrate rotation, a dynamic shadowing growth technique has been developed to fabricate catalytic nanomotors such as rotary Si/Pt nanorods, rotary L-shaped Si/Pt and Si/Ag nanorods, and rolling Si/Ag nanosprings, and their autonomous motions have been demonstrated in a diluted H2O2 solution. This fabrication method reveals an optimistic step toward designing integrated nanomachines. PMID:17430007

  14. Field investigation of the drift shadow

    USGS Publications Warehouse

    Su, G.W.; Kneafsey, T.J.; Ghezzehei, T.A.; Cook, P.J.; Marshall, B.D.

    2006-01-01

    The "Drift Shadow" is defined as the relatively drier region that forms below subsurface cavities or drifts in unsaturated rock. Its existence has been predicted through analytical and numerical models of unsaturated flow. However, these theoretical predictions have not been demonstrated empirically to date. In this project we plan to test the drift shadow concept through field investigations and compare our observations to simulations. Based on modeling studies we have an identified a suitable site to perform the study at an inactive mine in a sandstone formation. Pretest modeling studies and preliminary characterization of the site are being used to develop the field scale tests.

  15. Shadows for bump-mapped surfaces

    SciTech Connect

    Max, N.L.

    1985-11-05

    Bump mapping produces realistic shading by perturbing normal vectors to a surface, but does not show the shadows that the bumps cast on nearby parts of the same surface. In this paper, these shadows are found from precomputed tables of horizon angles, listing, for each position entry, the elevation of the horizon in a sampled collection of directions. These tables are made for bumps on a standard flat surface, and then a transformation is developed so that the same tables can be used for an arbitrary curved parameterized surface patch. This necessitates a new method for scaling the bump size to the patch size. 7 refs., 8 figs.

  16. FIELD INVESTIGATIONS OF THE DRIFT SHADOW

    SciTech Connect

    G. W. Su, T. J. Kneafsey, T. A. Ghezzehei, B. D. Marshall, and P. J. Cook

    2006-01-15

    The ''Drift Shadow'' is defined as the relatively drier region that forms below subsurface cavities or drifts in unsaturated rock. Its existence has been predicted through analytical and numerical models of unsaturated flow. However, these theoretical predictions have not been demonstrated empirically to date. In this project they plan to test the drift shadow concept through field investigations and compare our observations to simulations. Based on modeling studies they have an identified suitable site to perform the study at an inactive mine in a sandstone formation. Pretest modeling studies and preliminary characterization of the site are being used to develop the field scale tests.

  17. Object Based Agricultural Land Cover Classification Map of Shadowed Areas from Aerial Image and LIDAR Data Using Support Vector Machine

    NASA Astrophysics Data System (ADS)

    Alberto, R. T.; Serrano, S. C.; Damian, G. B.; Camaso, E. E.; Celestino, A. B.; Hernando, P. J. C.; Isip, M. F.; Orge, K. M.; Quinto, M. J. C.; Tagaca, R. C.

    2016-06-01

    Aerial image and LiDAR data offers a great possibility for agricultural land cover mapping. Unfortunately, these images leads to shadowy pixels. Management of shadowed areas for classification without image enhancement were investigated. Image segmentation approach using three different segmentation scales were used and tested to segment the image for ground features since only the ground features are affected by shadow caused by tall features. The RGB band and intensity were the layers used for the segmentation having an equal weights. A segmentation scale of 25 was found to be the optimal scale that will best fit for the shadowed and non-shadowed area classification. The SVM using Radial Basis Function kernel was then applied to extract classes based on properties extracted from the Lidar data and orthophoto. Training points for different classes including shadowed areas were selected homogeneously from the orthophoto. Separate training points for shadowed areas were made to create additional classes to reduced misclassification. Texture classification and object-oriented classifiers have been examined to reduced heterogeneity problem. The accuracy of the land cover classification using 25 scale segmentation after accounting for the shadow detection and classification was significantly higher compared to higher scale of segmentation.

  18. B-mode ultrasound-detected carotid artery lesions with and without acoustic shadowing and their association with markers of inflammation and endothelial activation: the atherosclerosis risk in communities study.

    PubMed

    Hunt, Kelly J; Pankow, James S; Offenbacher, Steven; Kritchevsky, Stephen B; Duncan, Bruce B; Shahar, Eyal; Sharrett, A Richey; Heiss, Gerardo

    2002-05-01

    In a cross-sectional study of 8695 men and women free of clinical CVD, aged 45-64 years at the 1987-1989 baseline Atherosclerosis Risk in Communities (ARIC) study exam, we examined the relationship between carotid artery lesions (CALs), with and without acoustic shadowing (AS) as an index of plaque mineralization, to systemic markers of inflammation and markers of endothelial function, including endothelial adhesion molecules. A three-level variable, based on the presence of extracranial CALs and AS, identified by B-mode ultrasound of six 1 cm arterial segments, defined the outcome. Among subjects without evidence of AS, after controlling for age, gender, ethnicity, study site, body mass index, hypertension, diabetes, and smoking status, CALs were associated with systemic markers of inflammation, including higher levels of fibrinogen [OR=1.24 (95% CI: 1.09, 1.40)] and white blood cell count [OR=1.37 (95% CI: 1.21, 1.56)]. Among subjects with a CAL, after controlling for the above risk factors as well as mean far wall intima-media thickness, AS was associated with higher levels of von Willebrand factor [OR=1.38 (95% CI: 1.10, 1.74)], a marker of endothelial activation. Associations with endothelial adhesion molecules were inconsistent. Further studies aimed at elucidating the mechanisms of arterial mineralization are warranted. PMID:11947908

  19. Eliminating rib shadows in chest radiographic images providing diagnostic assistance.

    PubMed

    Oğul, Hasan; Oğul, B Buket; Ağıldere, A Muhteşem; Bayrak, Tuncay; Sümer, Emre

    2016-04-01

    A major difficulty with chest radiographic analysis is the invisibility of abnormalities caused by the superimposition of normal anatomical structures, such as ribs, over the main tissue to be examined. Suppressing the ribs with no information loss about the original tissue would therefore be helpful during manual identification or computer-aided detection of nodules on a chest radiographic image. In this study, we introduce a two-step algorithm for eliminating rib shadows in chest radiographic images. The algorithm first delineates the ribs using a novel hybrid self-template approach and then suppresses these delineated ribs using an unsupervised regression model that takes into account the change in proximal thickness (depth) of bone in the vertical axis. The performance of the system is evaluated using a benchmark set of real chest radiographic images. The experimental results determine that proposed method for rib delineation can provide higher accuracy than existing methods. The knowledge of rib delineation can remarkably improve the nodule detection performance of a current computer-aided diagnosis (CAD) system. It is also shown that the rib suppression algorithm can increase the nodule visibility by eliminating rib shadows while mostly preserving the nodule intensity. PMID:26775736

  20. Video quality on AMLCD versus shadow-mask CRT

    NASA Astrophysics Data System (ADS)

    Olson, William P.; Balram, Nikhil

    1996-05-01

    The paper analyzes the image quality of video presented on the new AMLCD F/A-18 E/F multipurpose color display (MPCD) and compares it to the shadow-mask CRT based F/A-18 C/D MPCD. We focus on the contrast ratio advantages held by the AMLCD over the CRT and the resulting superior presentation of color map video and monochrome sensor video. We present modulation transfer functions (MTFs) for the E/F AMLCD and the C/D shadow-mask CRT, and combine these with the contrast threshold function (CTF) of the human visual system, to compute an objective image quality metric, the MTFA, that has been found to correlate well with performance in military detection and recognition tasks. The phase/space varying nature of the LCD requires the use of a multi-valued modulation transfer function (MMTF) in contrast to the single valued MTFs traditionally derived for phase/space invariant systems. The significant difference between the MTFAs for the E/F MPCD and the C/D MPCD highlight the superior image quality produced by the AMLCD. This superior image quality translates into better detection and recognition of target details from sensor video. Two additional metrics, the limiting resolution, and the SQRI, are also computed and used to confirm the overall conclusions.

  1. Comparison of Unsupervised Vegetation Classification Methods from Vhr Images after Shadows Removal by Innovative Algorithms

    NASA Astrophysics Data System (ADS)

    Movia, A.; Beinat, A.; Crosilla, F.

    2015-04-01

    The recognition of vegetation by the analysis of very high resolution (VHR) aerial images provides meaningful information about environmental features; nevertheless, VHR images frequently contain shadows that generate significant problems for the classification of the image components and for the extraction of the needed information. The aim of this research is to classify, from VHR aerial images, vegetation involved in the balance process of the environmental biochemical cycle, and to discriminate it with respect to urban and agricultural features. Three classification algorithms have been experimented in order to better recognize vegetation, and compared to NDVI index; unfortunately all these methods are conditioned by the presence of shadows on the images. Literature presents several algorithms to detect and remove shadows in the scene: most of them are based on the RGB to HSI transformations. In this work some of them have been implemented and compared with one based on RGB bands. Successively, in order to remove shadows and restore brightness on the images, some innovative algorithms, based on Procrustes theory, have been implemented and applied. Among these, we evaluate the capability of the so called "not-centered oblique Procrustes" and "anisotropic Procrustes" methods to efficiently restore brightness with respect to a linear correlation correction based on the Cholesky decomposition. Some experimental results obtained by different classification methods after shadows removal carried out with the innovative algorithms are presented and discussed.

  2. Pixel-wise orthogonal decomposition for color illumination invariant and shadow-free image.

    PubMed

    Qu, Liangqiong; Tian, Jiandong; Han, Zhi; Tang, Yandong

    2015-02-01

    In this paper, we propose a novel, effective and fast method to obtain a color illumination invariant and shadow-free image from a single outdoor image. Different from state-of-the-art methods for shadow-free image that either need shadow detection or statistical learning, we set up a linear equation set for each pixel value vector based on physically-based shadow invariants, deduce a pixel-wise orthogonal decomposition for its solutions, and then get an illumination invariant vector for each pixel value vector on an image. The illumination invariant vector is the unique particular solution of the linear equation set, which is orthogonal to its free solutions. With this illumination invariant vector and Lab color space, we propose an algorithm to generate a shadow-free image which well preserves the texture and color information of the original image. A series of experiments on a diverse set of outdoor images and the comparisons with the state-of-the-art methods validate our method. PMID:25836092

  3. Optical depth measurements by shadow-band radiometers and their uncertainties

    SciTech Connect

    Alexandrov, Mikhail; Kiedron, Peter; Michalsky, Joseph J.; Hodges, Gary; Flynn, Connor J.; Lacis, Andrew A.

    2007-11-20

    Shadow-band radiometers in general, and especially the Multi-Filter Rotating Shadow-band Radiometer (MFRSR), are widely used for atmospheric optical depth measurements. The major programs running MFRSR networks in the U.S. include DOE Atmospheric Radiation Measurement (ARM) Program, USDA UV-B Monitoring and Research Program, NOAA Surface Radiation (SURFRAD) Network, and NASA Solar Irradiance Research Network (SIRN). In this paper we discuss a number of technical issues specific for shadow-band radiometers and their impact on the optical depth measurements. These problems include instrument tilt and misalignment, as well as some data processing artifacts. Techniques for data evaluation and automatic detection of some of these problems are described.

  4. Optical depth measurements by shadow-band radiometers and their uncertainties

    SciTech Connect

    Alexandrov, Mikhail; Kiedron, Peter; Michalsky, Joseph J.; Hodges, Gary; Flynn, Connor J.; Lacis, Andrew A.

    2007-11-15

    Shadow-band radiometers in general, and especially the Multi-Filter Rotating Shadow-band Radiometer (MFRSR), are widely used for atmospheric optical depth measurements. The major programs running MFRSR networks in the U.S. include DOE Atmospheric Radiation Measurement (ARM) Program, USDA UV-B Monitoring and Research Program, NOAA Surface Radiation (SURFRAD) Network, and NASA Solar Irradiance Research Network (SIRN). In this paper we discuss a number of technical issues specific for shadow-band radiometers and their impact on the optical depth measurements. These problems include instrument tilt and misalignment, as well as somedata processing artifacts. Techniques for data evaluation and automatic detection of some of these problems are described.

  5. The Rural South: From Shadows to Sunshine.

    ERIC Educational Resources Information Center

    Winter, William F.

    2000-01-01

    The South can move out of the shadows of the harsh economic realities of the last 15 years and into the sunshine of developing new strategies to take advantage of the region's strengths. These strengths include a vast wealth of natural resources; a Sunbelt location; and most important, a huge reservoir of undeveloped human capital. The road to…

  6. Job Shadowing Introduces the Realities of Manufacturing

    ERIC Educational Resources Information Center

    Frawley, Thomas A.

    2009-01-01

    Engineers and skilled tradesmen stood side by side with executives and politicians as Liverpool High School technology teacher Dan Drogo welcomed parents to a one-of-a-kind graduation ceremony at New Process Gear in Syracuse, New York. The manufacturing shadow program had immersed 25 high school students in an intensive five-week experience inside…

  7. Shadows on the Internet. Teaching Science.

    ERIC Educational Resources Information Center

    Leyden, Michael

    1997-01-01

    Describes a world-wide science project aiming to help students measure the absence of light. The project is accomplished through the Internet. On the first day of Spring, students from all over the world will measure their shadows (absence of light) and use the information to compare and contrast data with that of other students participating in…

  8. Multithreshold progressive image sharing with compact shadows

    NASA Astrophysics Data System (ADS)

    Chen, Lee Shu-Teng; Lin, Ja-Chen

    2010-01-01

    We propose a multithreshold progressive reconstruction method. The image is encoded three times using Joint Photographic Experts Group (JPEG): first with a low-quality factor, then with a medium-quality factor, and last with a high-quality factor. Huffman coding is employed to encode the difference between the important image and the high-quality JPEG decompressed image. The three JPEG codes and the Huffman code are shared, respectively, according to four prespecified thresholds. The n-generated equally important shadows can be stored or transmitted using n channels in parallel. Cooperation among these generated shadows can progressively reconstruct the important image. The reconstructed image is loss-free when the number of collected shadows reaches the largest threshold. Each shadow is very compact and so can be hidden successfully in the JPEG codes of cover images to reduce the probability of being attacked when transmitted in an unfriendly environment. Comparisons with other image sharing methods are made. The contributions, such as easiness to apply to scalable Moving Picture Experts Group (MPEG) video transmission or resistance to differential attack, are also included.

  9. Shadow Science: Astronomy in the Schoolyard

    ERIC Educational Resources Information Center

    Denney, Janice

    2005-01-01

    It is natural to study astronomy outdoors, but it is not quite as natural to study astronomy during the daytime. This lesson uses the Earth's closest star as a subject of study within the schoolyard. The importance of the rising sun is combined with hands-on inquiry in which students explore the properties of shadows. Students (a) complete a…

  10. A novel real-time reverse transcription-polymerase chain reaction assay with partially double-stranded linear DNA probe for sensitive detection of hepatitis C viral RNA.

    PubMed

    Liu, Tianfu; Wan, Zhenzhou; Liu, Jia; Zhang, Lingyi; Zhou, Yanheng; Lan, Ke; Hu, Yihong; Zhang, Chiyu

    2016-10-01

    The detection and quantification of HCV RNA is very helpful for the management and treatment of HCV related diseases. Detection of low HCV viral load is a great challenge in HCV RNA detection. Here, we developed a novel real-time RT-PCR assay with partially double-stranded linear DNA probe which can detect all HCV genotypes and improve the detection performance. The novel assay has a wide linear dynamic range of HCV RNA quantification (1×10(2)-1×10(11)IU/ml) and a limit of detection of 78IU/ml. The assay exhibits an excellent reproducibility with 2.52% and 1.33% coefficients of variations, for inter- and intra-assays, respectively. To evaluate the viability of the assay, a comparison with a commercial HCV RNA detection kit was performed using 106 serum samples. The lineared correlation coefficient between the novel assay and the commercial HCV RNA detection kit was 0.940. Meanwhile, the deviation between the two methods was tolerable. Therefore, the novel real-time RT-PCR assay was applicable for laboratory diagnosis and monitoring of HCV infection. PMID:27451264

  11. Shadows Alter Facial Expressions of Noh Masks

    PubMed Central

    Kawai, Nobuyuki; Miyata, Hiromitsu; Nishimura, Ritsuko; Okanoya, Kazuo

    2013-01-01

    Background A Noh mask, worn by expert actors during performance on the Japanese traditional Noh drama, conveys various emotional expressions despite its fixed physical properties. How does the mask change its expressions? Shadows change subtly during the actual Noh drama, which plays a key role in creating elusive artistic enchantment. We here describe evidence from two experiments regarding how attached shadows of the Noh masks influence the observers’ recognition of the emotional expressions. Methodology/Principal Findings In Experiment 1, neutral-faced Noh masks having the attached shadows of the happy/sad masks were recognized as bearing happy/sad expressions, respectively. This was true for all four types of masks each of which represented a character differing in sex and age, even though the original characteristics of the masks also greatly influenced the evaluation of emotions. Experiment 2 further revealed that frontal Noh mask images having shadows of upward/downward tilted masks were evaluated as sad/happy, respectively. This was consistent with outcomes from preceding studies using actually tilted Noh mask images. Conclusions/Significance Results from the two experiments concur that purely manipulating attached shadows of the different types of Noh masks significantly alters the emotion recognition. These findings go in line with the mysterious facial expressions observed in Western paintings, such as the elusive qualities of Mona Lisa’s smile. They also agree with the aesthetic principle of Japanese traditional art “yugen (profound grace and subtlety)”, which highly appreciates subtle emotional expressions in the darkness. PMID:23940748

  12. Acoustic shadows help gleaning bats find prey, but may be defeated by prey acoustic camouflage on rough surfaces.

    PubMed

    Clare, Elizabeth L; Holderied, Marc W

    2015-01-01

    Perceptual abilities of animals, like echolocating bats, are difficult to study because they challenge our understanding of non-visual senses. We used novel acoustic tomography to convert echoes into visual representations and compare these cues to traditional echo measurements. We provide a new hypothesis for the echo-acoustic basis of prey detection on surfaces. We propose that bats perceive a change in depth profile and an 'acoustic shadow' cast by prey. The shadow is more salient than prey echoes and particularly strong on smooth surfaces. This may explain why bats look for prey on flat surfaces like leaves using scanning behaviour. We propose that rather than forming search images for prey, whose characteristics are unpredictable, predators may look for disruptions to the resting surface (acoustic shadows). The fact that the acoustic shadow is much fainter on rougher resting surfaces provides the first empirical evidence for 'acoustic camouflage' as an anti-predator defence mechanism. PMID:26327624

  13. Partial solubility parameters of lactose, mannitol and saccharose using the modified extended Hansen method and evaporation light scattering detection.

    PubMed

    Peña, M A; Daali, Y; Barra, J; Bustamante, P

    2000-02-01

    The modified extended Hansen method was tested for the first time to determine partial solubility parameters of non-polymeric pharmaceutical excipients. The method was formerly tested with drug molecules, and is based upon a regression analysis of the logarithm of the mole fraction solubility of the solute against the partial solubility parameters of a series of solvents of different chemical classes. Two monosaccharides and one disaccharide (lactose monohydrate, saccharose and mannitol) were chosen. The solubility of these compounds was determined in a series of solvents ranging from nonpolar to polar and covering a wide range of the solubility parameter scale. Sugars do not absorb at the UV-vis region, and the saturated solutions were assayed with a recent chromatographic technique coupled to an evaporative light scattering detector. This technique was suitable to determine the concentration dissolved in most solvents. The modified extended Hansen method provided better results than the original approach. The best model was the four parameter equation, which includes the dispersion delta d, dipolar delta p, acidic delta a and basic delta b partial solubility parameters. The partial solubility parameters obtained, expressed as MPa1/2, were delta d = 17.6, delta p = 28.7, delta h = 19, delta a = 14.5, delta b = 12.4, delta T = 32.8 for lactose, delta d = 16.2, delta p = 24.5, delta h = 14.6, delta a = 8.7, delta b = 12.2, delta T = 32.8 for mannitol and delta d = 17.1, delta p = 18.5, delta h = 13, delta a = 11.3, delta b = 7.6, delta T = 28.4 for saccharose. The high total solubility parameters delta T obtained agree with the polar nature of the sugars. The dispersion parameters delta d are quite similar for the three sugars indicating that the polar delta p and hydrogen bonding parameters (delta h, delta a, delta b) are responsible for the variation in the total solubility parameters delta T obtained, as also found for drugs. The results suggest that the method

  14. Generating soft shadows with a depth buffer algorithm

    NASA Technical Reports Server (NTRS)

    Brotman, L. S.; Badler, N. I.

    1984-01-01

    Computer-synthesized shadows used to appear with a sharp edge when cast onto a surface. At present the production of more realistic, soft shadows is considered. However, significant costs arise in connection with such a representation. The current investigation is concerned with a pragmatic approach, which combines an existing shadowing method with a popular visible surface rendering technique, called a 'depth buffer', to generate soft shadows resulting from light sources of finite extent. The considered method represents an extension of Crow's (1977) shadow volume algorithm.

  15. Shadows of Kerr black holes with and without scalar hair

    NASA Astrophysics Data System (ADS)

    Cunha, Pedro V. P.; Herdeiro, Carlos A. R.; Radu, Eugen; Rúnarsson, Helgi F.

    2016-06-01

    For an observer, the Black Hole (BH) shadow is the BHs apparent image in the sky due to the gravitational lensing of nearby radiation, emitted by an external source. A recent class of solutions dubbed Kerr BHs with scalar hair possess smaller shadows than the corresponding Kerr BHs and, under some conditions, novel exotic shadow shapes can arise. Thus, these hairy BHs could potentially provide new shadow templates for future experiments such as the Event Horizon Telescope. In order to obtain the shadows, the backward ray-tracing algorithm is briefly introduced, followed by numerical examples of shadows of Kerr BHs with scalar hair contrasting with the Kerr analogues. Additionally, an analytical solution for the Kerr shadow is derived in closed form for a ZAMO observer at an arbitrary position.

  16. Shadows of multi-black holes: Analytic exploration

    NASA Astrophysics Data System (ADS)

    Yumoto, Akifumi; Nitta, Daisuke; Chiba, Takeshi; Sugiyama, Naoshi

    2012-11-01

    Shadows of multi-black holes have structures distinct from the mere superposition of the shadow of a single black hole: the eyebrow-like structures outside the main shadows and the deformation of the shadows. We present analytic estimates of these structures using the static multi-black hole solution (Majumdar-Papapetrou solution). We show that the width of the eyebrow is related to the distance between the black holes and that the shadows are deformed into ellipses due to the presence of the second black holes. These results are helpful to understand qualitatively the features of the shadows of colliding black holes. We also present the shadows of colliding or coalescing black holes in the Kastor-Traschen solution.

  17. The sculpting of Jupiter's gossamer rings by its shadow

    NASA Astrophysics Data System (ADS)

    Hamilton, Douglas P.; Krüger, Harald

    2008-05-01

    Dust near Jupiter is produced when interplanetary impactors collide energetically with small inner moons, and is organized into a main ring, an inner halo, and two fainter and more distant gossamer rings. Most of these structures are constrained by the orbits of the moons Adrastea, Metis, Amalthea and Thebe, but a faint outward protrusion called the Thebe extension behaves differently and has eluded understanding. Here we report on dust impacts detected during the Galileo spacecraft's traversal of the outer ring region: we find a gap in the rings interior to Thebe's orbit, grains on highly inclined paths, and a strong excess of submicrometre-sized dust just inside Amalthea's orbit. We present detailed modelling that shows that the passage of ring particles through Jupiter's shadow creates the Thebe extension and fully accounts for these Galileo results. Dust grains alternately charge and discharge when traversing shadow boundaries, allowing the planet's powerful magnetic field to excite orbital eccentricities and, when conditions are right, inclinations as well.

  18. The sculpting of Jupiter's gossamer rings by its shadow.

    PubMed

    Hamilton, Douglas P; Krüger, Harald

    2008-05-01

    Dust near Jupiter is produced when interplanetary impactors collide energetically with small inner moons, and is organized into a main ring, an inner halo, and two fainter and more distant gossamer rings. Most of these structures are constrained by the orbits of the moons Adrastea, Metis, Amalthea and Thebe, but a faint outward protrusion called the Thebe extension behaves differently and has eluded understanding. Here we report on dust impacts detected during the Galileo spacecraft's traversal of the outer ring region: we find a gap in the rings interior to Thebe's orbit, grains on highly inclined paths, and a strong excess of submicrometre-sized dust just inside Amalthea's orbit. We present detailed modelling that shows that the passage of ring particles through Jupiter's shadow creates the Thebe extension and fully accounts for these Galileo results. Dust grains alternately charge and discharge when traversing shadow boundaries, allowing the planet's powerful magnetic field to excite orbital eccentricities and, when conditions are right, inclinations as well. PMID:18451856

  19. FIELD INVESTIGATION OF THE DRIFT SHADOW

    SciTech Connect

    G.W. Su; T.J. Kneafsey

    2006-02-01

    A drift shadow is an area immediately beneath an underground void that, in theory, will be relatively drier than the surrounding rock mass. Numerical and analytical models of water flow through unsaturated rock predict the existence of a drift shadow, but field tests confirming the existence of the drift shadow have yet to be performed. Proving the existence of drift shadows and understanding their hydrologic and transport characteristics could provide a better understanding of how contaminants move in the subsurface if released from waste emplacement drifts such as the proposed nuclear waste repository at Yucca Mountain, Nevada. We describe the field program that will be used to investigate the existence of a drift shadow--and the corresponding hydrological process at the Hazel-Atlas silica-sand mine located at the Black Diamond Mines Regional Preserve in Antioch, California. The location and configuration of this mine makes it an excellent site to observe and measure drift shadow characteristics. The mine is located in a porous sandstone unit of the Domengine formation, an approximately 230 meter thick series of interbedded Eocene-age shales, coals, and massive-bedded sandstones. The mining method used at the mine required the development of two parallel drifts, one above the other, driven along the strike of the mined sandstone stratum. This configuration provides the opportunity to introduce water into the rock mass in the upper drift and to observe and measure its flow around the underlying drift. The passive and active hydrologic tests to be performed are described. In the passive method, cores will be obtained in a radial pattern around a drift and will be sectioned and analyzed for in-situ water content using a gravimetric technique, as well as analyzed for chemistry. With the active hydrologic test, water will be introduced into the upper drift of the two parallel drifts and the flow of the water will be tracked as it passes near the bottom drift

  20. Initial condition from the shadowed Glauber model

    NASA Astrophysics Data System (ADS)

    Chatterjee, Sandeep; Singh, Sushant K.; Ghosh, Snigdha; Hasanujjaman, Md; Alam, Jane; Sarkar, Sourav

    2016-07-01

    The two component Monte-Carlo Glauber model predicts a knee-like structure in the centrality dependence of elliptic flow v2 in Uranium + Uranium collisions at √{sNN} = 193 GeV. It also produces a strong anti-correlation between v2 and dNch / dy in the case of top ZDC events. However, none of these features have been observed in data. We address these discrepancies by including the effect of nucleon shadowing to the two component Monte-Carlo Glauber model. Apart from addressing successfully the above issues, we find that the nucleon shadow suppresses the event by event fluctuation of various quantities, e.g. ε2 which is in accordance with expectation from the dynamical models of initial condition based on gluon saturation physics.

  1. Shadow of rotating wormhole in plasma environment

    NASA Astrophysics Data System (ADS)

    Abdujabbarov, Ahmadjon; Juraev, Bakhtinur; Ahmedov, Bobomurat; Stuchlík, Zdeněk

    2016-07-01

    The massless particle motion around rotating wormhole in the presence of plasma environment has been studied. It has been shown that the presence of the plasma decreases the inner radius of the circular orbits of photons around rotating wormhole. The shadow cast by rotating wormhole surrounded by inhomogeneous plasma with the radial power-law density has been explored. It has been shown that the shape and size of the wormhole shadow is distorted and changed depending on i) plasma parameters, ii) wormhole rotation and iii) inclination angle between observer plane and axis of rotation of wormhole. As an example we have considered an inverse radial distribution of the plasma density and different types of the wormhole solution.

  2. Deep shadows in a shallow box

    NASA Astrophysics Data System (ADS)

    Huang, Xiang; Mohan, Ankit; Tumblin, Jack

    2008-02-01

    We present a fast, low-cost technique to gather high-contrast 'relightable' photographs of desktop-sized objects. Instead of an elaborate light stage, we follow Mohan et al.; we place the object and a digitally steered spotlight inside a white cardboard box, aim the spotlight at the box interior, and move the spot to light the object from N repeatable lighting directions. However, strong ambient lighting from box interreflections causes 'shallow' shadows and reduces contrasts in all basis images. We show how to remove this ambient lighting computationally from the N images, by measuring an N ×N matrix of coupling factors between lighting directions using a mirrorsphere light probe. This linear method, suitable for any light stage, creates physically accurate 'deep shadow' basis images, yet imposes only a modest noise penalty, and does not require external light metering or illumination angle measurements. Results from our demonstration system support these claims.

  3. Cloud and Cloud Shadow Masking Using Multi-Temporal Cloud Masking Algorithm in Tropical Environmental

    NASA Astrophysics Data System (ADS)

    Candra, D. S.; Phinn, S.; Scarth, P.

    2016-06-01

    A cloud masking approach based on multi-temporal satellite images is proposed. The basic idea of this approach is to detect cloud and cloud shadow by using the difference reflectance values between clear pixels and cloud and cloud shadow contaminated pixels. Several bands of satellite image which have big difference values are selected for developing Multi-temporal Cloud Masking (MCM) algorithm. Some experimental analyses are conducted by using Landsat-8 images. Band 3 and band 4 are selected because they can distinguish between cloud and non cloud. Afterwards, band 5 and band 6 are used to distinguish between cloud shadow and clear. The results show that the MCM algorithm can detect cloud and cloud shadow appropriately. Moreover, qualitative and quantitative assessments are conducted using visual inspections and confusion matrix, respectively, to evaluate the reliability of this algorithm. Comparison between this algorithm and QA band are conducted to prove the reliability of the approach. The results show that MCM better than QA band and the accuracy of the results are very high.

  4. Examining Model Fidelity via Shadowing Time

    NASA Astrophysics Data System (ADS)

    Du, H.; Smith, L. A.

    2014-12-01

    Fully fledged climate models provide the best available simulations for reflecting the future, yet we have scant insight into their fidelity, in particular as to the duration into the future at which the real world should be expected to evolve in a manner today's models cannot foresee. We know now that our best available models are not adequate for many sought after purposes. To throw some light on the maximum fidelity expected from a given generation of models, and thereby aid both policy making and model development, we can test the weaknesses of a model as a dynamical system to get an informed idea of its potential applicability at various lead times. Shadowing times reflect the duration on which a GCM reflects the observed dynamics of the Earth; extracting the shortcomings of the model which limit shadowing times allows informed speculation regarding the fidelity of the model in the future. More specifically, by identifying the reasons models cannot shadow we learn the relevant phenomena limiting model fidelity, we can then look at the time scales on which feedbacks on the system (which are not active in the model) are likely to result in model irrelevance. The methodology is developed in the "low dimensional laboratory" of relatively simple dynamical systems, for example Lorenz 95 systems. The results are presented in Lorenz 95 systems as well as GCMs. There are severe limits on the light shadowing experiments can shine on GCM predictions. Never the less, they appear to be one of the brightest lights we can shine to illuminate the likely fidelity of GCM extrapolations into the future.

  5. Non-uniformly hyperbolic flows and shadowing

    NASA Astrophysics Data System (ADS)

    Sun, Wenxiang; Tian, Xueting; Vargas, Edson

    2016-07-01

    We consider a hyperbolic ergodic measure of a C1 flow on a compact manifold. Under the hypothesis that there are no fixed points and that the Oseledec splitting of the normal bundle satisfies a limit domination property, we prove that the measure has a shadowing property. As an application of this result we prove that the measure can be approached on the weak* topology by measures supported on hyperbolic periodic orbits.

  6. Shadowing Lemma and chaotic orbit determination

    NASA Astrophysics Data System (ADS)

    Spoto, Federica; Milani, Andrea

    2016-03-01

    Orbit determination is possible for a chaotic orbit of a dynamical system, given a finite set of observations, provided the initial conditions are at the central time. The Shadowing Lemma (Anosov 1967; Bowen in J Differ Equ 18:333-356, 1975) can be seen as a way to connect the orbit obtained using the observations with a real trajectory. An orbit is a shadowing of the trajectory if it stays close to the real trajectory for some amount of time. In a simple discrete model, the standard map, we tackle the problem of chaotic orbit determination when observations extend beyond the predictability horizon. If the orbit is hyperbolic, a shadowing orbit is computed by the least squares orbit determination. We test both the convergence of the orbit determination iterative procedure and the behaviour of the uncertainties as a function of the maximum number of map iterations observed. When the initial conditions belong to a chaotic orbit, the orbit determination is made impossible by numerical instability beyond a computability horizon, which can be approximately predicted by a simple formula. Moreover, the uncertainty of the results is sharply increased if a dynamical parameter is added to the initial conditions as parameter to be estimated. The Shadowing Lemma does not dictate what the asymptotic behaviour of the uncertainties should be. These phenomena have significant implications, which remain to be studied, in practical problems of orbit determination involving chaos, such as the chaotic rotation state of a celestial body and a chaotic orbit of a planet-crossing asteroid undergoing many close approaches.

  7. High-Resolution Shadowing of Transfer RNA

    PubMed Central

    Abermann, Reinhard J.; Yoshikami, Doju

    1972-01-01

    High-resolution shadowing with metals that melt at high temperatures was used to study macromolecules. Molecules of transfer RNA shadowed with tantalum-tungsten are readily visualized in an electron microscope. Mounting procedures for tRNA were perfected that reproducibly gave uniform distributions of both monomeric and dimeric tRNA particles, and allowed a statistical assessment of their gross shapes and sizes. Monomeric tRNA yielded a fairly homogeneous population of rod-shaped particles, with axial dimensions of about 40 × 85 Å. Dimers of yeast alanine tRNA held together by hydrogen bonds and dimers constructed by covalent linkage of the amino-acid acceptor (3′-) termini of monomers both gave slightly more heterogeneous populations of particles. Yet, their structures were also basically rod shaped, with their lengths ranging to about twice that of the monomer; this result indicates an end-to-end arrangement of the monomeric units within both dimers. These results suggest that the amino-acid acceptor terminus and the anticodon region are at the ends of the rod-shaped, dehydrated tRNA monomer visible by electron microscopy, consistent with the generally accepted view of tRNA structure in solution suggested by other workers using other methods. This study demonstrates that high-resolution shadowing with tantalum-tungsten provides a means to examine the three-dimensional structures of relatively small biological macromolecules. Images PMID:4504373

  8. Design of a New Built-in UHF Multi-Frequency Antenna Sensor for Partial Discharge Detection in High-Voltage Switchgears.

    PubMed

    Zhang, Xiaoxing; Cheng, Zheng; Gui, Yingang

    2016-01-01

    In this study a new built-in ultrahigh frequency (UHF) antenna sensor was designed and applied in a high-voltage switchgear for partial discharge (PD) detection. The casing of the switchgear was initially used as the ground plane of the antenna sensor, which integrated the sensor into the high-voltage switchgear. The Koch snowflake patch was adopted as the radiation patch of the antenna to overcome the disadvantages of common microstrip antennas, and the feed position and the dielectric layer thickness were simulated in detail. Simulation results show that the antenna sensor possessed four resonant points with good impedance matching from 300 MHz to 1000 MHz, and it also presented good multi-frequency performance in the entire working frequency band. PD detection experiments were conducted in the high-voltage switchgear, and the fabricated antenna sensor was effectively built into the high-voltage switchgear. In order to reflect the advantages of the built-in antenna sensor, another external UHF antenna sensor was used as a comparison to simultaneously detect PD. Experimental results demonstrated that the built-in antenna sensor possessed high detection sensitivity and strong anti-interference capacity, which ensured the practicability of the design. In addition, it had more high-voltage switchgear PD detection advantages than the external sensor. PMID:27472331

  9. Field Investigation of the Drift Shadow

    NASA Astrophysics Data System (ADS)

    Su, G. W.; Kneafsey, T. J.; Ghezzehei, T. A.; Marshall, B. D.; Cook, P. J.

    2005-12-01

    A drift shadow is an area immediately beneath an underground void that, in theory, will be relatively drier than the surrounding rock mass. Numerical and analytical models of water flow through unsaturated rock predict the existence of a drift shadow, but field tests confirming its existence have yet to be performed. Proving the existence of drift shadows and understanding their hydrologic and transport characteristics could provide a better understanding of how contaminants move in the subsurface if released from waste emplacement drifts such as the proposed nuclear waste repository at Yucca Mountain, Nevada. We describe the field program that will be used to investigate the existence of a drift shadow and the corresponding hydrological process at the Hazel-Atlas silica-sand mine located at the Black Diamond Mines Regional Preserve in Antioch, California. The location and configuration of this mine makes it an excellent site to observe and measure drift shadow characteristics. The mine is located in a porous sandstone unit of the Domengine Formation, an approximately 230 meter thick series of interbedded Eocene-age shales, coals, and massive-bedded sandstones. The mining method used at the mine required the development of two parallel drifts, one above the other, driven along the strike of the mined sandstone stratum. This configuration provides the opportunity to introduce water into the rock mass in the upper drift and to observe and measure its flow around the underlying drift. The passive and active hydrologic tests to be performed are described. In the passive method, cores will be obtained in a radial pattern around a drift and will be sectioned and analyzed for in-situ water content and chemical constituents. With the active hydrologic test, water will be introduced into the upper drift of the two parallel drifts and the flow of the water will be tracked as it passes near the bottom drift. Tensiometers, electrical resistance probes, neutron probes, and

  10. Cloud and Cloud Shadow Identification for MERIS and Sentinel-3/OLCI

    NASA Astrophysics Data System (ADS)

    Pringle, Nicholas; Vanhellemont, Quinten; Ruddick, Kevin

    2015-12-01

    Ocean colour remote sensing has become a well-established method for the monitoring of coastal waters. The MERIS chlorophyll product for turbid waters (algal_2) and the total suspended matter product (tsm) have been used in applications such as algal bloom detection, eutrophication monitoring, and coastal sediment transport. These MERIS L2 products are sometimes contaminated by cloud shadow pixels and the same problems are likely to occur in Sentinel-3. In order to avoid erroneous data passing quality control and being used in applications, an automated method for detecting and removing cloud and cloud shadow pixels is needed. With this in mind, we highlight the problems with MERIS in the past and show some results from applying detection methods to Landsat-8 data with the objective of using these methods for Sentinel-2 and -3 in the future.

  11. Quality assessment of gasoline using comprehensive two-dimensional gas chromatography combined with unfolded partial least squares: A reliable approach for the detection of gasoline adulteration.

    PubMed

    Parastar, Hadi; Mostafapour, Sara; Azimi, Gholamhasan

    2016-01-01

    Comprehensive two-dimensional gas chromatography and flame ionization detection combined with unfolded-partial least squares is proposed as a simple, fast and reliable method to assess the quality of gasoline and to detect its potential adulterants. The data for the calibration set are first baseline corrected using a two-dimensional asymmetric least squares algorithm. The number of significant partial least squares components to build the model is determined using the minimum value of root-mean square error of leave-one out cross validation, which was 4. In this regard, blends of gasoline with kerosene, white spirit and paint thinner as frequently used adulterants are used to make calibration samples. Appropriate statistical parameters of regression coefficient of 0.996-0.998, root-mean square error of prediction of 0.005-0.010 and relative error of prediction of 1.54-3.82% for the calibration set show the reliability of the developed method. In addition, the developed method is externally validated with three samples in validation set (with a relative error of prediction below 10.0%). Finally, to test the applicability of the proposed strategy for the analysis of real samples, five real gasoline samples collected from gas stations are used for this purpose and the gasoline proportions were in range of 70-85%. Also, the relative standard deviations were below 8.5% for different samples in the prediction set. PMID:26541637

  12. Measuring saliency of features using signal-to-noise ratios for detection of electrocardiographic changes in partial epileptic patients.

    PubMed

    Ubeyli, Elif Derya

    2008-12-01

    Medical diagnostic accuracies can be improved when the pattern is simplified through representation by important features. The feature vector, which is comprised of the set of all features used to describe a pattern, is a reduced-dimensional representation of that pattern. By identifying a set of salient features, the noise in a classification model can be reduced, resulting in more accurate classification. In this study, a signal-to-noise ratio (SNR) saliency measure was employed to determine saliency of input features of probabilistic neural networks (PNNs) used in classification of two types of electrocardiogram (ECG) beats (normal and partial epilepsy). In order to extract features representing the ECG signals, discrete wavelet transform was used. The PNNs used in the ECG signals classification were trained for the SNR screening method. The application results of the SNR screening method to the ECG signals demonstrated that classification accuracies of the PNNs with salient input features are higher than that of the PNNs with salient and non-salient input features. PMID:19058650

  13. The influence of cast shadows on visual search.

    PubMed

    Rensink, Ronald A; Cavanagh, Patrick

    2004-01-01

    We show that cast shadows can have a significant influence on the speed of visual search. In particular, we find that search based on the shape of a region is affected when the region is darker than the background and corresponds to a shadow formed by lighting from above. Results support the proposal that an early-level system rapidly identifies regions as shadows and then discounts them, making their shapes more difficult to access. Several constraints used by this system are mapped out, including constraints on the luminance and texture of the shadow region, and on the nature of the item casting the shadow. Among other things, this system is found to distinguish between line elements (items containing only edges) and surface elements (items containing visible surfaces), with only the latter deemed capable of casting a shadow. PMID:15693675

  14. A 1K Shadow RAM for circumvention applications

    SciTech Connect

    Murray, J.R.

    1991-01-01

    A 1K bit Shadow RAM has been developed for storage of critical data in a high transient radiation environment. The circuit includes a 1K bit (128 {times} 8) static RAM with two non-volatile (NV) shadows. The NV shadows are used to back-up the data in the static RAM allowing the circuit to be powered down during transient radiation without losing critical data. This paper will describe the circuit's operation and characterization results.

  15. Low-cost telemedicine device performing cell and particle size measurement based on lens-free shadow imaging technology.

    PubMed

    Roy, Mohendra; Seo, Dongmin; Oh, Chang-Hyun; Nam, Myung-Hyun; Kim, Young Jun; Seo, Sungkyu

    2015-05-15

    Recent advances in lens-free shadow imaging technology have enabled a new class of cell imaging platform, which is a suitable candidate for point-of-care facilities. In this paper, we firstly demonstrate a compact and low-cost telemedicine device providing automated cell and particle size measurement based on lens-free shadow imaging technology. Using the generated shadow (or diffraction) patterns, the proposed approach can detect and measure the sizes of more than several hundreds of micro-objects simultaneously within a single digital image frame. In practical experiments, we defined four types of shadow parameters extracted from each micro-object shadow pattern, and found that a specific shadow parameter (peak-to-peak distance, PPD) demonstrated a linear relationship with the actual micro-object sizes. By using this information, a new algorithm suitable for operation on both a personal computer (PC) and a cell phone was also developed, providing automated size detection of poly-styrenemicro-beads and biological cells such as red blood cells, MCF-7, HepG2, and HeLa. Results from the proposed device were compared with those of a conventional optical microscope, demonstrating good agreement between two approaches. In contrast to other existing cell and particle size measurement approaches, such as Coulter counter, flow-cytometer, particle-size analyzer, and optical microscope, this device can provide accurate cell and particle size information with a 2 µm maximum resolution, at almost no cost (less than 100 USD), within a compact instrumentation size (9.3×9.0×9.0 cm(3)), and in a rapid manner (within 1 min). The proposed lens-free automated particle and cell size measurement device, based on shadow imaging technology, can be utilized as a powerful tool for many cell and particle handling procedures, including environmental, pharmaceutical, biological, and clinical applications. PMID:25459053

  16. Detection of melamine in milk powders using near-infrared hyperspectral imaging combined with regression coefficient of partial least square regression model.

    PubMed

    Lim, Jongguk; Kim, Giyoung; Mo, Changyeun; Kim, Moon S; Chao, Kuanglin; Qin, Jianwei; Fu, Xiaping; Baek, Insuck; Cho, Byoung-Kwan

    2016-05-01

    Illegal use of nitrogen-rich melamine (C3H6N6) to boost perceived protein content of food products such as milk, infant formula, frozen yogurt, pet food, biscuits, and coffee drinks has caused serious food safety problems. Conventional methods to detect melamine in foods, such as Enzyme-linked immunosorbent assay (ELISA), High-performance liquid chromatography (HPLC), and Gas chromatography-mass spectrometry (GC-MS), are sensitive but they are time-consuming, expensive, and labor-intensive. In this research, near-infrared (NIR) hyperspectral imaging technique combined with regression coefficient of partial least squares regression (PLSR) model was used to detect melamine particles in milk powders easily and quickly. NIR hyperspectral reflectance imaging data in the spectral range of 990-1700nm were acquired from melamine-milk powder mixture samples prepared at various concentrations ranging from 0.02% to 1%. PLSR models were developed to correlate the spectral data (independent variables) with melamine concentration (dependent variables) in melamine-milk powder mixture samples. PLSR models applying various pretreatment methods were used to reconstruct the two-dimensional PLS images. PLS images were converted to the binary images to detect the suspected melamine pixels in milk powder. As the melamine concentration was increased, the numbers of suspected melamine pixels of binary images were also increased. These results suggested that NIR hyperspectral imaging technique and the PLSR model can be regarded as an effective tool to detect melamine particles in milk powders. PMID:26946026

  17. Highly Selective Mercury Detection at Partially Oxidized Graphene/Poly(3,4-ethylenedioxythiophene):Poly(styrenesulfonate) Nanocomposite Film Modified Electrode

    NASA Astrophysics Data System (ADS)

    Yasri, Nael; Sundramoorthy, Ashok; Chang, Woo-Jin; Gunasekaran, Sundaram

    2014-12-01

    Partially oxidized graphene flakes (po-Gr) were obtained from graphite electrode by an electrochemical exfoliation method. As-produced po-Gr flakes were dispersed in water with the assistance of poly(3,4-ethylenedioxythiophene)/poly(styrenesulfonate) (PEDOT:PSS). The po-Gr flakes and the po-Gr/PEDOT:PSS nanocomposite (po-Gr/PEDOT:PSS) were characterized by Raman spectroscopy, Fourier transform-infrared spectroscopy (FT-IR), UV-Vis spectroscopy, X-ray diffraction (XRD) and scanning electron microscopy (SEM). In addition, we demonstrated the potential use of po-Gr/PEDOT:PSS electrode in electrochemical detection of mercury ions (Hg2+) in water samples. The presence of po-Gr sheets in PEDOT:PSS film greatly enhanced the electrochemical response for Hg2+. Cyclic voltammetry measurements showed a well-defined Hg2+ redox peaks with a cathodic peak at 0.23 V, and an anodic peak at 0.42 V. Using differential pulse stripping voltammetry, detection of Hg2+ was achieved in the range of 0.2 to 14 µM (R2 = 0.991), with a limit of detection (LOD) of 0.19 µM for Hg2+. The electrode performed satisfactorily for sensitive and selective detection of Hg2+ in real samples, and the po-Gr/PEDOT:PSS film remains stable on the electrode surface for repeated use. Therefore, our method is potentially suitable for routine Hg2+ sensing in environmental water samples.

  18. Seismoelectric coupling in partially water-saturated porous media: From the theory to the detection of saturation fronts

    NASA Astrophysics Data System (ADS)

    Revil, A.; Barnier, G.; Sava, P. C.; Jardani, A.; Kulessa, B.

    2014-12-01

    The seismoelectric method is based on the interpretation of the electrical field associated with the conversion of mechanical to electromagnetic energy during the propagation of seismic waves in heterogeneous porous media. We propose a poroacoustic model. This model takes into account fluid flow and the effect of the partial saturation of the water phase and is coupled with an electrokinetic model accounting for the effect of saturation. The model is in agreement with available experimental data in a variety of porous media. We also developed new scaling laws for the permeability, the streaming potential coupling coefficient, and the capillary entry pressure of porous media. The theory is developed for frequencies much below the critical frequency at which inertial effects starts to dominate in the Navier-Stokes equation (>10 kHz). The equations used to compute the propagation of the P-waves and the seismoelectric effect in unsaturated condition are solved with finite elements using triangular meshing. A first example demonstrates the usefulness of the seismoelectric beamforming, to localize saturation fronts by focusing seismic waves and looking at the resulting seismoelectric conversions. This method is applied to a cross-hole problem showing how a saturation front characterized by a drop in the electrical conductivity and compressibility is responsible for seismoelectric conversions. These conversions can be used in turn to determine the position of the front over time. The figure shows the dipolar anomaly resulting from the beamforming of seimiec energy at point A and associated with a resistivity contrast. Finally, we show how a complete two-phase flow seismoelectric theory can be developed based on the extension of the dynamic Biot theory to two-phase flow conditions and how this theory can be numerically implemented.

  19. Sputter shadowing improved by using a tungsten target.

    PubMed

    Colquhoun, W R; Cassimeris, L U

    1985-05-01

    This work builds upon a previous paper (W. Colquhoun, 1984, J. Ultrastruct. Res. 87, 97) in which a sputter shadowing device was briefly described. The device allowed TEM specimens to be shadowed in a conventional sputter coater. Images obtained by sputter shadowing with a standard Au/Pd target were of good quality but were slightly inferior to the best that could be obtained by e--beam evaporation of tungsten. Here we show that construction and use of a tungsten target greatly improves the quality of the sputter shadowed deposit. Images of DNA and ribosomal subunits contrasted by sputter shadowing with tungsten are shown. The DNA images indicate that sputter shadowing with tungsten is a gentle contrasting technique. The sputter shadowed images of the 30 S ribosomal subunits show the major features of the particle revealed by evaporation shadowing using the most sophisticated of methods in that technology. Advantages of sputter shadowing are discussed and a rationale for the improved grain obtained by sputtering tungsten is suggested. PMID:2935642

  20. Perception of Shadows in Children with Autism Spectrum Disorders

    PubMed Central

    Becchio, Cristina; Mari, Morena; Castiello, Umberto

    2010-01-01

    Background Cast shadows in visual scenes can have profound effects on visual perception. Much as they are informative, they also constitute noise as they are salient features of the visual scene potentially interfering with the processing of other features. Here we asked i) whether individuals with autism can exploit the information conveyed by cast shadows; ii) whether they are especially sensitive to noise aspects of shadows. Methodology/Principal Findings Twenty high-functioning children with autism and twenty typically developing children were asked to recognize familiar objects while the presence, position, and shape of the cast shadow were systematically manipulated. Analysis of vocal reaction time revealed that whereas typically developing children used information from cast shadows to improve object recognition, in autistic children the presence of cast shadows—either congruent or incongruent—interfered with object recognition. Critically, vocal reaction times were faster when the object was presented without a cast shadow. Conclusions/Significance We conclude that shadow-processing mechanisms are abnormal in autism. As a result, processing shadows becomes costly and cast shadows interfere rather than help object recognition. PMID:20485498

  1. N-expansive homeomorphisms with the shadowing property

    NASA Astrophysics Data System (ADS)

    Carvalho, B.; Cordeiro, W.

    2016-09-01

    We discuss the dynamics of n-expansive homeomorphisms with the shadowing property defined on compact metric spaces. For every n ∈ N, we exhibit an n-expansive homeomorphism, which is not (n - 1)-expansive, has the shadowing property and admits an infinite number of chain-recurrent classes. We discuss some properties of the local stable (unstable) sets of n-expansive homeomorphisms with the shadowing property and use them to prove that some types of the limit shadowing property are present. This deals some direction to the problem of non-existence of topologically mixing n-expansive homeomorphisms that are not expansive.

  2. Shadow prediction model for the International Space Station Alpha

    SciTech Connect

    Chung, D.K.

    1995-12-31

    A Fortran computer model, SHADOW5, was developed to predict shadows on the solar arrays of the International Space Station Alpha (ISSA) for general flight modes. This shadow model was incorporated into the EPSOP-F (Electrical Power System On-Orbit Performance) program to conduct ISSA power analyses for various operating conditions. This paper describes the mathematical methods of the model and shows the typical results predicted with the model. Vector analyses with coordinate transformations were used to trace the shadows between the potential shadowing and shadowed components of the station during the sun portion of the orbit. Including the space shuttle orbiter, 40 components were modeled. The basic shapes of the components were assumed to be either planar or cylindrical. The elemental areas obtained from the Cartesian grid lines allocated on the component surfaces were projected in the sun vector direction to reconstruct shadows on the shadowed planar surface. Comparison of predicted results with other models showed good agreement. Ease of preparing input data and relatively short CPU time make this model suitable for shadow analyses required for the many design and flight configurations of the space station.

  3. A comparative study of intervention methods (full, partial and non-integration) on late case detection and treatment irregularity in Yangon, Myanmar.

    PubMed

    Pangi, C; Shwe, T; Win, D L; Saw, W W; Gyi, K K; Yee, M; Myint, Y Y; Htay, T T

    1998-01-01

    The high percentage (20%) of new cases with grade 2 disabilities, and a low treatment regularity of 47% indicated problems in case detection and case holding in Urban Yangon. The fact that Urban Health Centers (UHCs) were not involved in leprosy control programme might have had an adverse influence. To compare the effectiveness of two methods of integration (full and partial) of urban leprosy services in terms of early case detection and regularity of treatment this study was conducted, in an urban area. Two townships with similar leprosy prevalence, staff infrastructure, socio-economic status, transport, communication and working capacity of the Township Medical Officers (TMOs) were chosen for this intervention study: UHC-A(Thingangyun) for full integration and UHC-B(Tamwe) for partial integration and the remaining 14 townships as non-integrated areas served by the Central Special Skin Clinic (CSSC). This study has shown that it was possible to fully integrate Leprosy Control Programme (LCP) into the Urban Health Centres [Basic Health Services (BHS)] in Urban Yangon. Case detection could be improved by active case finding such as contact examination and school examination conducted by the personnel of UHCs. Treatment regularity was found to be directly proportional to prompt defaulter retrieval action and the motivational level of the TMO and peripheral BHS workers. There were more complaints from patients (8.1%) treated at UHC-A when compared to CSSC (6.7%). Among defaulters there were more adults than children, more males than females and more PB than MB patients. PMID:10992872

  4. The Orbit of Mimas Through Titan's Shadow

    NASA Astrophysics Data System (ADS)

    Consolmagno, G. J.; Hubbard, W. B.; Hill, R.; Boyle, R. P.

    1996-09-01

    We recorded a rare mutual event of Mimas and Titan's shadow on the evening of November 9-10 1995 at the Vatican Advanced Technology Telescope (VATT: the Alice P. Lennon telescope and the Thomas J. Bannan facility) on Mt. Graham, Arizona, using a fast occultation CCD imaging system. The shadows of Rhea and Titan were also seen moving across the rings of Saturn itself. Our primary sequence of observations consist of six hundred images of the east ansa of Saturn's ring, each a three second exposure through the R filter, taken from 4:02 to 4:32 UT November 10. Saturn itself was masked from the CCD chip. Each pixel of the chip represented 0.3 arc- seconds. Seeing reached as good as 1.3 arc-seconds, but the focus of the VATT was not corrected during the run as the mirrors cooled, reducing the quality of some of the images. (With Gregorian optics, changes of as little as 5 microns in path length can significantly degrade the focus.) A passing weather front also provided challenges; though the telescope was remarkably stable even aimed into the wind, passing clouds degraded about 5-10% of our images. The predicted time of the event was 4:22:21 to 4:25:22 UT. A clear dip in brightness of Mimas occurs in our data between these times. Further analysis leading to a more precise timing of the shadow- Mimas event can give improved precision to the ephemeris of Mimas' orbit.

  5. Field investigation of the drift shadow

    SciTech Connect

    Su, Grace W.; Kneafsey, Timothy J.; Ghezzehei, Teamrat A.; Marshall, Brian D.; Cook, Paul J.

    2005-09-08

    A drift shadow is an area immediately beneath an undergroundvoidthat, in theory, will be relatively drier than the surrounding rockmass. Numerical and analytical models of water flow through unsaturatedrock predict the existence of a drift shadow, but field tests confirmingits existence have yet to be performed. Proving the existence of driftshadows and understanding their hydrologic and transport characteristicscould provide a better understanding of how contaminants move in thesubsurface if released from waste emplacement drifts such as the proposednuclear waste repository at Yucca Mountain, Nevada. We describe the fieldprogram that will be used to investigate the existence of a drift shadowand the corresponding hydrological process at the Hazel-Atlas silica-sandmine located at the Black Diamond Mines Regional Preserve in Antioch,California. The location and configuration of this mine makes it anexcellent site to observe and measure drift shadow characteristics. Themine is located in a porous sandstone unit of the Domengine Formation, anapproximately 230 meter thick series of interbedded Eocene-age shales,coals, and massive-bedded sandstones. The mining method used at the minerequired the development of two parallel drifts, one above the other,driven along the strike of the mined sandstone stratum. Thisconfiguration provides the opportunity to introduce water into the rockmass in the upper drift and to observe and measure its flow around theunderlying drift. The passive and active hydrologic tests to be performedare described. In the passive method, cores will be obtained in a radialpattern around a drift and will be sectioned and analyzed for in-situwater content and chemical constituents. With the active hydrologic test,water will be introduced into the upper drift of the two parallel driftsand the flow of the water will be tracked as it passes near the bottomdrift. Tensiometers, electrical resistance probes, neutron probes, andground penetrating radar may be

  6. Langmuir Probe Measurements in Plasma Shadows

    SciTech Connect

    Waldmann, O.; Koch, B.; Fussmann, G.

    2006-01-15

    When immersing a target into a plasma streaming along magnetic field lines, a distinct shadow region extending over large distances is observed by the naked eye downstream of the target.In this work we present an experimental study of the effect applying Langmuir probes. In contrast to expectations, there are only marginal changes in the profiles of temperature and density behind masks that cut away about 50% of the plasma cross-section. On the other hand, the mean density is drastically reduced by an order of magnitude. First attempts to simulate the observations by solving the classical 2D diffusion equation were not successful.

  7. Shadow bands in models of correlated electrons

    SciTech Connect

    Moreo, A.; Haas, S.; Dagotto, E.

    1995-08-01

    A consequence of strong antiferromagnetic correlations in models of high-Tc cuprates is the appearance in photoemission (PES) calculations of considerable more weight above the Fermi momentum p{sub F} than expected for non-interacting electrons. This effect, qualitatively discussed by Kampf and Schrieffer under the name of {open_quotes}shadow bands{close_quotes}, is here quantitatively analyzed in the two dimensional Hubbard and t-J models using Monte Carlo and exact diagonalization techniques in the realistic strong coupling regime.

  8. Framework for dynamic background modeling and shadow suppression for moving object segmentation in complex wavelet domain

    NASA Astrophysics Data System (ADS)

    Kushwaha, Alok Kumar Singh; Srivastava, Rajeev

    2015-09-01

    Moving object segmentation using change detection in wavelet domain under continuous variations of lighting condition is a challenging problem in video surveillance systems. There are several methods proposed in the literature for change detection in wavelet domain for moving object segmentation having static backgrounds, but it has not been addressed effectively for dynamic background changes. The methods proposed in the literature suffer from various problems, such as ghostlike appearance, object shadows, and noise. To deal with these issues, a framework for dynamic background modeling and shadow suppression under rapidly changing illumination conditions for moving object segmentation in complex wavelet domain is proposed. The proposed method consists of eight steps applied on given video frames, which include wavelet decomposition of frame using complex wavelet transform; use of change detection on detail coefficients (LH, HL, and HH), use of improved Gaussian mixture-based dynamic background modeling on approximate coefficient (LL subband); cast shadow suppression; use of soft thresholding for noise removal; strong edge detection; inverse wavelet transformation for reconstruction; and finally using closing morphology operator. A comparative analysis of the proposed method is presented both qualitatively and quantitatively with other standard methods available in the literature for six datasets in terms of various performance measures. Experimental results demonstrate the efficacy of the proposed method.

  9. Simultaneous Determination of Iron, Copper and Cobalt in Food Samples by CCD-diode Array Detection-Flow Injection Analysis with Partial Least Squares Calibration Model

    NASA Astrophysics Data System (ADS)

    Mi, Jiaping; Li, Yuanqian; Zhou, Xiaoli; Zheng, Bo; Zhou, Ying

    2006-01-01

    A flow injection-CCD diode array detection spectrophotometry with partial least squares (PLS) program for simultaneous determination of iron, copper and cobalt in food samples has been established. The method was based on the chromogenic reaction of the three metal ions and 2- (5-Bromo-2-pyridylazo)-5-diethylaminophenol, 5-Br-PADAP in acetic acid - sodium acetate buffer solution (pH5) with Triton X-100 and ascorbic acid. The overlapped spectra of the colored complexes were collected by charge-coupled device (CCD) - diode array detector and the multi-wavelength absorbance data was processed using partial least squares (PLS) algorithm. Optimum reaction conditions and parameters of flow injection analysis were investigated. The samples of tea, sesame, laver, millet, cornmeal, mung bean and soybean powder were determined by the proposed method. The average recoveries of spiked samples were 91.80%~100.9% for Iron, 92.50%~108.0% for Copper, 93.00%~110.5% for Cobalt, respectively with relative standard deviation (R.S.D) of 1.1%~12.1%. The sampling rate is 45 samples h-1. The determination results of the food samples were in good agreement between the proposed method and ICP-AES.

  10. Simultaneous determination of tin, germanium and molybdenum by diode array detection-flow injection analysis with partial least squares calibration model.

    PubMed

    Zou, Xiaoli; Li, Yuanqian; Li, Menglong; Zheng, Bo; Yang, Jingguo

    2004-03-10

    Simultaneous determination of tin, germanium and molybdenum in food samples has been established by flow injection-charge coupled detector (CCD) diode array detection spectrophotometry with partial least squares (PLS) algorithm. The method was based on the chromogenic reaction of metal ions and salicylflurone in the presence of cetyltrimethyl ammonium bromide. The overlapping spectra of these complexes are collected by CCD diode array detector and the multi-wavelength absorbance data are processed using partial least squares algorithm. The reaction conditions and analytical parameters of flow injection analysis have been investigated. The method was applied to directly determine Ge, Mo and Sn in several food samples after digestion with satisfactory results. The recoveries of spiked samples were 80.0-102.0% for tin, 86.3-92.0% for germanium and 83.2-95.2% for molybdenum, and the relative standard deviations for samples were 4.4-7.8%. Molybdenum in certified reference material of cattle liver was determined by the proposed method (n=8). The differential values between determined and guarantee values were within the given uncertain value ranges (t=1.687, P>0.05 for t-test). The samples of mung bean, kelp and pork liver were analyzed by the proposed method and inductively couple plasma-atomic emission spectroscopy (ICP-AES) method. The determination results of the two methods are in good agreement. The sampling rate is 30 samplesh(-1). PMID:18969354

  11. Articulatory events are imitated under rapid shadowing

    PubMed Central

    Honorof, Douglas N.; Weihing, Jeffrey; Fowler, Carol A.

    2013-01-01

    We tested the hypothesis that rapid shadowers imitate the articulatory gestures that structure acoustic speech signals—not just acoustic patterns in the signals themselves—overcoming highly practiced motor routines and phonological conditioning in the process. In a first experiment, acoustic evidence indicated that participants reproduced allophonic differences between American English /l/ types (light and dark) in the absence of the positional variation cues more typically present with lateral allophony. However, imitative effects were small. In a second experiment, varieties of /l/ with exaggerated light/dark differences were presented by ear. Acoustic measures indicated that all participants reproduced differences between /l/ types; larger average imitative effects obtained. Finally, we examined evidence for imitation in articulation. Participants ranged in behavior from one who did not imitate to another who reproduced distinctions among light laterals, dark laterals and /w/, but displayed a slight but inconsistent tendency toward enhancing imitation of lingual gestures through a slight lip protrusion. Overall, results indicated that most rapid shadowers need not substitute familiar allophones as they imitate reorganized gestural constellations even in the absence of explicit instruction to imitate, but that the extent of the imitation is small. Implications for theories of speech perception are discussed. PMID:23418398

  12. [Simultaneous determination of iron, copper and cobalt in food samples by diode array detection-flow injection analysis using partial least squares calibration model].

    PubMed

    Mi, Jian-Ping; Li, Yuan-Qian; Zou, Xiao-Li; Zheng, Bo; Yang, Jing-Guo

    2007-06-01

    A flow injection-CCD-diode array detection spectrophotometric method using partial least squares (PLS) algorithm for the simultaneous determination of iron, copper and cobalt in food samples has been established. The method was based on the chromogenic reaction between metallic ions and 5-Br-PADAP in the presence of acetic acid-acetic sodium buffer solution (pH 5) containing 30 g x L(-1) ascorbic acid and 2% (phi) Triton X-100. The overlapped spectra of these complexes were collected by CCD diode array detector and the multi-wavelength absorbance data were processed using partial least squares algorithm. The reaction conditions and analytical parameters of FIA were investigated. The food samples can be analyzed without any separation after digestion, and the sampling rate was 45 x h(-1). The linear ranges of Fe2+, Cu+ and Co2+ were 0.2-10.0 microg x mL(-1), 0.1-5.0 microg x mL(-1), and 0.01-1.0 microg x mL(-1) and the detection limits were 0.2, 0.1 and 0.01 microg x mL(-1), respectively. The average recoveries of spiked samples were 89.4%-110.8% for the three elements. The relative standard deviation (RSD) of samples was in the range of 1.1%-12.1%. Comparing the proposed method with ICP-AES, the relative error was below 12.1%. Above all, this method is simple, quick, sensitive, selective, and easy to be apply and generalize. PMID:17763789

  13. Quasi-static displacement calibration system for a "Violin-Mode" shadow-sensor intended for Gravitational Wave detector suspensions.

    PubMed

    Lockerbie, N A; Tokmakov, K V

    2014-10-01

    This paper describes the design of, and results from, a calibration system for optical linear displacement (shadow) sensors. The shadow sensors were designed to detect "Violin-Mode" (VM) resonances in the 0.4 mm diameter silica fibre suspensions of the test masses/mirrors of Advanced Laser Interferometer Gravitational Wave Observatory gravitational wave interferometers. Each sensor illuminated the fibre under test, so as to cast its narrow shadow onto a "synthesized split photodiode" detector, the shadow falling over adjacent edges of the paired photodiodes. The apparatus described here translated a vertically orientated silica test fibre horizontally through a collimated Near InfraRed illuminating beam, whilst simultaneously capturing the separate DC "shadow notch" outputs from each of the paired split photodiode detectors. As the ratio of AC to DC photocurrent sensitivities to displacement was known, a calibration of the DC response to quasi-static shadow displacement allowed the required AC sensitivity to vibrational displacement to be found. Special techniques are described for generating the required constant scan rate for the test fibre using a DC motor-driven stage, for removing "jitter" at such low translation rates from a linear magnetic encoder, and so for capturing the two shadow-notch signals at each micrometre of the test fibre's travel. Calibration, across the four detectors of this work, gave a vibrational responsivity in voltage terms of (9.45 ± 1.20) MV (rms)/m, yielding a VM displacement sensitivity of (69 ± 13) pm (rms)/√Hz, at 500 Hz, over the required measuring span of ±0.1 mm. PMID:25362445

  14. Quasi-static displacement calibration system for a "Violin-Mode" shadow-sensor intended for Gravitational Wave detector suspensions

    NASA Astrophysics Data System (ADS)

    Lockerbie, N. A.; Tokmakov, K. V.

    2014-10-01

    This paper describes the design of, and results from, a calibration system for optical linear displacement (shadow) sensors. The shadow sensors were designed to detect "Violin-Mode" (VM) resonances in the 0.4 mm diameter silica fibre suspensions of the test masses/mirrors of Advanced Laser Interferometer Gravitational Wave Observatory gravitational wave interferometers. Each sensor illuminated the fibre under test, so as to cast its narrow shadow onto a "synthesized split photodiode" detector, the shadow falling over adjacent edges of the paired photodiodes. The apparatus described here translated a vertically orientated silica test fibre horizontally through a collimated Near InfraRed illuminating beam, whilst simultaneously capturing the separate DC "shadow notch" outputs from each of the paired split photodiode detectors. As the ratio of AC to DC photocurrent sensitivities to displacement was known, a calibration of the DC response to quasi-static shadow displacement allowed the required AC sensitivity to vibrational displacement to be found. Special techniques are described for generating the required constant scan rate for the test fibre using a DC motor-driven stage, for removing "jitter" at such low translation rates from a linear magnetic encoder, and so for capturing the two shadow-notch signals at each micrometre of the test fibre's travel. Calibration, across the four detectors of this work, gave a vibrational responsivity in voltage terms of (9.45 ± 1.20) MV (rms)/m, yielding a VM displacement sensitivity of (69 ± 13) pm (rms)/√Hz, at 500 Hz, over the required measuring span of ±0.1 mm.

  15. A ‘Violin-Mode’ shadow sensor for interferometric gravitational wave detectors

    NASA Astrophysics Data System (ADS)

    Lockerbie, N. A.; Tokmakov, K. V.

    2014-12-01

    This paper describes a system of four novel shadow detectors having, collectively, a displacement sensitivity of (69  ±  13) picometres (rms) / √Hz, at 500 Hz, over a measuring span of ±0.1 mm. The detectors were designed to monitor the vibrations of the 600 mm long, 400 μm diameter, silica suspension fibres of the mirrors for the Advanced LIGO (Laser Interferometer Gravitational wave Observatory) gravitational wave detectors, at the resonances of the so-called Violin Modes (VM). The VM detection system described here had a target sensitivity of 100 pm (rms)/ √Hz at 500 Hz, together with, ultimately, a required detection span of ±0.1 mm about the mean position of each fibre—in order to compensate for potential slow drift over time of fibre position, due to mechanical relaxation. The full sensor system, comprising emitters (sources of illumination) and shadow detectors, therefore met these specifications. Using these sensors, VM resonances having amplitudes of 1.2 nm (rms) were detected in the suspension fibres of an Advanced LIGO dummy test-mass. The VM bandwidth of the sensor, determined by its transimpedance amplifier, was 226 Hz-8.93 kHz at the -3 dB points. This paper focuses mainly on the detector side of the shadow sensors. The emitters are described in an accompanying paper.

  16. Self-Attributed Body-Shadows Modulate Tactile Attention

    ERIC Educational Resources Information Center

    Pavani, Francesco; Galfano, Giovanni

    2007-01-01

    Our body-shadows are special stimuli in the visual world. They often have anatomical resemblance with our own body-parts and move as our body moves, with spatio-temporal correlation. Here, we show that self-attributed body-shadows cue attention to the body-part they refer to, rather than the location they occupy. Using speeded spatial…

  17. Studying in the Shadow of 9/11

    ERIC Educational Resources Information Center

    Konkel, Jeff

    2007-01-01

    The shadow of the Twin Towers will never again stretch across the streets of lower Manhattan, but the shadow of September 11 continues to loom large both in New York and around the globe. In many ways, the events of that day are directly responsible for the latest technical program offering at two high schools in Missouri's St. Louis County. In…

  18. Creation of Mice Bearing a Partial Duplication of HPRT Gene Marked with a GFP Gene and Detection of Revertant Cells In Situ as GFP-Positive Somatic Cells

    PubMed Central

    Noda, Asao; Suemori, Hirofumi; Hirai, Yuko; Hamasaki, Kanya; Kodama, Yoshiaki; Mitani, Hiroshi; Landes, Reid D.; Nakamura, Nori

    2015-01-01

    It is becoming clear that apparently normal somatic cells accumulate mutations. Such accumulations or propagations of mutant cells are thought to be related to certain diseases such as cancer. To better understand the nature of somatic mutations, we developed a mouse model that enables in vivo detection of rare genetically altered cells via GFP positive cells. The mouse model carries a partial duplication of 3’ portion of X-chromosomal HPRT gene and a GFP gene at the end of the last exon. In addition, although HPRT gene expression was thought ubiquitous, the expression level was found insufficient in vivo to make the revertant cells detectable by GFP positivity. To overcome the problem, we replaced the natural HPRT-gene promoter with a CAG promoter. In such animals, termed HPRT-dup-GFP mouse, losing one duplicated segment by crossover between the two sister chromatids or within a single molecule of DNA reactivates gene function, producing hybrid HPRT-GFP proteins which, in turn, cause the revertant cells to be detected as GFP-positive cells in various tissues. Frequencies of green mutant cells were measured using fixed and frozen sections (liver and pancreas), fixed whole mount (small intestine), or by means of flow cytometry (unfixed splenocytes). The results showed that the frequencies varied extensively among individuals as well as among tissues. X-ray exposure (3 Gy) increased the frequency moderately (~2 times) in the liver and small intestine. Further, in two animals out of 278 examined, some solid tissues showed too many GFP-positive cells to score (termed extreme jackpot mutation). Present results illustrated a complex nature of somatic mutations occurring in vivo. While the HPRT-dup-GFP mouse may have a potential for detecting tissue-specific environmental mutagens, large inter-individual variations of mutant cell frequency cause the results unstable and hence have to be reduced. This future challenge will likely involve lowering the background mutation

  19. Moving Shadows, Moving Sun. Early Modem Sundials Restaging Miracles.

    PubMed

    Mersmann, Jasmin

    2015-01-01

    Irrespective of geo- or heliocentric presuppositions, the functioning of sundials is based on the observation of moving shadows or light spots. Even though the cast shadow was often simply used to indicate the time, it could also remind the users of the ephemerality of earthly things or function as an index of planetary movements. This article examines the various ways in which early modem sundials visually interpret the moving shadow or light spot. The instruments address the shadow in inscriptions, integrate it into their design (e.g., in cruciform dials) or even manipulate its course (as in the so-called Horologium Ahaz). Both the crucifix and the Ahaz dials not only refer to astronomical miracles but actually restage them. Even though by means of the horologium it was not possible to explain the Old Testament miracle of the shadow moving backward, adepts were able to recreate it on a terrestrial scale. PMID:26495586

  20. On various definitions of shadowing with average error in tracing

    NASA Astrophysics Data System (ADS)

    Wu, Xinxing; Oprocha, Piotr; Chen, Guanrong

    2016-07-01

    When computing a trajectory of a dynamical system, influence of noise can lead to large perturbations which can appear, however, with small probability. Then when calculating approximate trajectories, it makes sense to consider errors small on average, since controlling them in each iteration may be impossible. Demand to relate approximate trajectories with genuine orbits leads to various notions of shadowing (on average) which we consider in the paper. As the main tools in our studies we provide a few equivalent characterizations of the average shadowing property, which also partly apply to other notions of shadowing. We prove that almost specification on the whole space induces this property on the measure center which in turn implies the average shadowing property. Finally, we study connections among sensitivity, transitivity, equicontinuity and (average) shadowing.

  1. Asphalted road temperature variations due to wind turbine cast shadows.

    PubMed

    Arnay, Rafael; Acosta, Leopoldo; Sigut, Marta; Toledo, Jonay

    2009-01-01

    The contribution of this paper is a technique that in certain circumstances allows one to avoid the removal of dynamic shadows in the visible spectrum making use of images in the infrared spectrum. This technique emerged from a real problem concerning the autonomous navigation of a vehicle in a wind farm. In this environment, the dynamic shadows cast by the wind turbines' blades make it necessary to include a shadows removal stage in the preprocessing of the visible spectrum images in order to avoid the shadows being misclassified as obstacles. In the thermal images, dynamic shadows completely disappear, something that does not always occur in the visible spectrum, even when the preprocessing is executed. Thus, a fusion on thermal and visible bands is performed. PMID:22291541

  2. Asphalted Road Temperature Variations Due to Wind Turbine Cast Shadows

    PubMed Central

    Arnay, Rafael; Acosta, Leopoldo; Sigut, Marta; Toledo, Jonay

    2009-01-01

    The contribution of this paper is a technique that in certain circumstances allows one to avoid the removal of dynamic shadows in the visible spectrum making use of images in the infrared spectrum. This technique emerged from a real problem concerning the autonomous navigation of a vehicle in a wind farm. In this environment, the dynamic shadows cast by the wind turbines' blades make it necessary to include a shadows removal stage in the preprocessing of the visible spectrum images in order to avoid the shadows being misclassified as obstacles. In the thermal images, dynamic shadows completely disappear, something that does not always occur in the visible spectrum, even when the preprocessing is executed. Thus, a fusion on thermal and visible bands is performed. PMID:22291541

  3. [Four cases of pulmonary tuberculosis resembling pulmonary abscess with a so-called niveau-like shadow in a medical school hospital: discussion concerning the formation mechanism of niveau-like shadows].

    PubMed

    Kobashi, Y; Niki, Y; Kawane, H; Matsushima, T

    1996-04-01

    Four cases of pulmonary tuberculosis resembling pulmonary abscess radiographically were reviewed from their clinical features, chest X-ray and chest CT, and the mechanism of formation of so-called niveau-like shadows was discussed. Only one case showed a newly formed tuberculous cavity with air fluid level on chest X-ray, however, even in this case, the possibility of the infection with tubercle bacilli of an emphysematous bulla of the lung could not be completely excluded as several bulla were found on chest CT. The remaining three cases showed a slightly different mechanism of the formation of niveau-like shadows. Namely, mycobacterium tuberculosis spread into an existed bulla and a tubercle bacilli infected bulla was formed. Regarding the clinical features, no remarkable findings were detected and we could find no differences with common tuberculosis. Based on these experiences, the presence of pulmonary tuberculosis resembling the shadow of pulmonary abscess should be emphasized. PMID:8683908

  4. The Effects of Self-shadowing by a Puffed-up Inner Rim in Scattered Light Images of Protoplanetary Disks

    NASA Astrophysics Data System (ADS)

    Dong, Ruobing

    2015-09-01

    We explore whether protoplanetary disks with self-shadowing from puffed-up inner rims exhibit observable features in scattered light images. We use both self-consistent hydrostatic equilibrium calculations and parameterized models to produce the vertically puffed-up inner rims. We find that, in general, the transition between the shadowed and flared regions occurs in a smooth manner over a broad radius range, and no sudden jump exists at the outer edge of the shadow in either the disk temperature or density structures. As a result, a puffed-up rim cannot create sharp ring/arc/spiral-arm-like features in the outer disk as have been detected in recent direct near-infrared imaging of disks. On the other hand, if the puffed-up rim has a sharp edge in the vertical direction, the shadowing effect can produce a distinct three-stage broken power law in the radial intensity profile of the scattered light, with two steep surface brightness radial profiles in the inner and outer disk joined by a shallow transition region around the shadow edge. These types of scattered light profiles may have already been observed, such as in the recent Subaru direct imaging of the TW Hydrae system.

  5. Increased Detection of Lymphatic Vessel Invasion by D2-40 (Podoplanin) in Early Breast Cancer: Possible Influence on Patient Selection for Accelerated Partial Breast Irradiation

    SciTech Connect

    Debald, Manuel; Poelcher, Martin; Flucke, Uta; Walgenbach-Bruenagel, Gisela

    2010-07-15

    Purpose: Several international trials are currently investigating accelerated partial breast irradiation (APBI) for patients with early-stage breast cancer. According to existing guidelines, patients with lymphatic vessel invasion (LVI) do not qualify for APBI. D2-40 (podoplanin) significantly increases the frequency of LVI detection compared with conventional hematoxylin and eosin (HE) staining in early-stage breast cancer. Our purpose was to retrospectively assess the hypothetical change in management from APBI to whole breast radiotherapy with the application of D2-40. Patients and Methods: Immunostaining with D2-40 was performed on 254 invasive breast tumors of 247 patients. The following criteria were used to determine the eligibility for APBI: invasive ductal adenocarcinoma of {<=}3 cm, negative axillary node status (N0), and unifocal disease. Of the 247 patients, 74 with available information concerning LVI, as detected by D2-40 immunostaining and routine HE staining, formed our study population. Results: Using D2-40, our results demonstrated a significantly greater detection rate (p = .031) of LVI compared with routine HE staining. LVI was correctly identified by D2-40 (D2-40-positive LVI) in 10 (13.5%) of 74 tumors. On routine HE staining, 4 tumors (5.4%) were classified as HE-positive LVI. Doublestaining of these specimens with D2-40 unmasked false-positive LVI status in 2 (50%) of the 4 tumors. According to the current recommendations for APBI, immunostaining with D2-40 would have changed the clinical management from APBI to whole breast radiotherapy in 8 (10.8%) of 74 patients and from whole breast radiotherapy to APBI in 2 patients (2.7%). Conclusion: These data support the implementation of D2-40 immunostaining in the routine workup to determine a patient's eligibility for APBI.

  6. Measuring the Kerr spin parameter of regular black holes from their shadow

    SciTech Connect

    Li, Zilong; Bambi, Cosimo E-mail: bambi@fudan.edu.cn

    2014-01-01

    In a previous paper, one of us has showed that, at least in some cases, the Kerr-nature of astrophysical black hole candidates is extremely difficult to test and current techniques, even in presence of excellent data not available today, cannot distinguish a Kerr black hole from a Bardeen one, despite the substantial difference of the two backgrounds. In this paper, we investigate if the detection of the ''shadow'' of nearby super-massive black hole candidates by near future mm/sub-mm very long baseline interferometry experiments can do the job. More specifically, we consider the measurement of the Kerr spin parameter of the Bardeen and Hayward regular black holes from their shadow, and we then compare the result with the estimate inferred from the Kα iron line and from the frequency of the innermost stable circular orbit. For non-rotating black holes, the shadow approach provides different values, and therefore the Kerr black hole hypothesis can potentially be tested. For near extremal objects, all the approaches give quite similar results, and therefore it is not possible to constrain deviations from the Kerr solution. The present work confirms that it is definitively challenging to test this kind of metrics, even with future facilities. However, the detection of a source that looks like a fast-rotating Kerr black hole can put meaningful constraints on the nature of the compact object.

  7. Measuring the Kerr spin parameter of regular black holes from their shadow

    NASA Astrophysics Data System (ADS)

    Li, Zilong; Bambi, Cosimo

    2014-01-01

    In a previous paper, one of us has showed that, at least in some cases, the Kerr-nature of astrophysical black hole candidates is extremely difficult to test and current techniques, even in presence of excellent data not available today, cannot distinguish a Kerr black hole from a Bardeen one, despite the substantial difference of the two backgrounds. In this paper, we investigate if the detection of the ``shadow'' of nearby super-massive black hole candidates by near future mm/sub-mm very long baseline interferometry experiments can do the job. More specifically, we consider the measurement of the Kerr spin parameter of the Bardeen and Hayward regular black holes from their shadow, and we then compare the result with the estimate inferred from the Kα iron line and from the frequency of the innermost stable circular orbit. For non-rotating black holes, the shadow approach provides different values, and therefore the Kerr black hole hypothesis can potentially be tested. For near extremal objects, all the approaches give quite similar results, and therefore it is not possible to constrain deviations from the Kerr solution. The present work confirms that it is definitively challenging to test this kind of metrics, even with future facilities. However, the detection of a source that looks like a fast-rotating Kerr black hole can put meaningful constraints on the nature of the compact object.

  8. Chest wall segmentation in automated 3D breast ultrasound using rib shadow enhancement and multi-plane cumulative probability enhanced map

    NASA Astrophysics Data System (ADS)

    Kim, Hyeonjin; Kim, Hannah; Hong, Helen

    2015-03-01

    We propose an automatic segmentation method of chest wall in 3D ABUS images using rib shadow enhancement and multi-planar cumulative probability enhanced map. For the identification of individual dark rib shadows, each rib shadow is enhanced using intensity transfer function and 3D sheet-like enhancement filtering. Then, wrongly enhanced intercostal regions and small fatty tissues are removed using coronal and sagittal cumulative probability enhanced maps. The large fatty tissues with globular and sheet-like shapes at the top of rib shadow are removed using shape and orientation analysis based on moment matrix. Detected chest walls are connected with cubic B-spline interpolation. Experimental results show that the Dice similarity coefficient of proposed method as comparison with two manually outlining results provides over 90% in average.

  9. Observations of shadow bands at the total solar eclipse of 16 February 1980

    NASA Technical Reports Server (NTRS)

    Marschall, L. A.; Mahon, R.; Henry, R. C.

    1984-01-01

    Photoelectric observations of short term light variations (shadow bands) at the 16 Feb. 1980 total solar eclipse have been made using a set of spatially separated PIN diodes. Light variations in a bandpass of 1-500 Hz were detected during the half-minutes preceding and following the total phase. Fourier analysis of the noise spectrum of the variations reveals a sharp drop-off for frequencies above 50 Hz and an overall spectrum quite similar to previously reported power spectra of stellar scintillation. This is consistent with an atmospheric origin for the shadow bands. Cross-correlations between the detector outputs are low, suggesting a short persistence time for the turbulent elements causing the patterns.

  10. An Approach to Alleviate the False Alarm in Building Change Detection from Urban Vhr Image

    NASA Astrophysics Data System (ADS)

    Chen, J.; Hou, J. L.; Deng, M.

    2016-06-01

    Building change detection from very-high-resolution (VHR) urban remote sensing image frequently encounter the challenge of serious false alarm caused by different illumination or viewing angles in bi-temporal images. An approach to alleviate the false alarm in urban building change detection is proposed in this paper. Firstly, as shadows casted by urban buildings are of distinct spectral and shape feature, it adopts a supervised object-based classification technique to extract them in this paper. Secondly, on the opposite direction of sunlight illumination, a straight line is drawn along the principal orientation of building in every extracted shadow region. Starting from the straight line and moving toward the sunlight direction, a rectangular area is constructed to cover partial shadow and rooftop of each building. Thirdly, an algebra and geometry invariant based method is used to abstract the spatial topological relationship of the potential unchanged buildings from all central points of the rectangular area. Finally, based on an oriented texture curvature descriptor, an index is established to determine the actual false alarm in building change detection result. The experiment results validate that the proposed method can be used as an effective framework to alleviate the false alarm in building change detection from urban VHR image.

  11. Partial spread OFDM

    NASA Astrophysics Data System (ADS)

    Elghariani, Ali; Zoltowski, Michael D.

    2012-05-01

    In this paper, partial spread OFDM system has been presented and its performance has been studied when different detection techniques are employed, such as minimum mean square error (MMSE), grouped Maximum Likelihood (ML) and approximated integer quadratic programming (IQP) techniques . The performance study also includes applying two different spreading matrices, Hadamard and Vandermonde. Extensive computer simulation have been implemented and important results show that partial spread OFDM system improves the BER performance and the frequency diversity of OFDM compared to both non spread and full spread systems. The results from this paper also show that partial spreading technique combined with suboptimal detector could be a better solution for applications that require low receiver complexity and high information detectability.

  12. Building detection in SAR imagery

    SciTech Connect

    Steinbach, Ryan Matthew

    2015-04-01

    Current techniques for building detection in Synthetic Aperture Radar (SAR) imagery can be computationally expensive and/or enforce stringent requirements for data acquisition. I present two techniques that are effective and efficient at determining an approximate building location. This approximate location can be used to extract a portion of the SAR image to then perform a more robust detection. The proposed techniques assume that for the desired image, bright lines and shadows, SAR artifact effects, are approximately labeled. These labels are enhanced and utilized to locate buildings, only if the related bright lines and shadows can be grouped. In order to find which of the bright lines and shadows are related, all of the bright lines are connected to all of the shadows. This allows the problem to be solved from a connected graph viewpoint, where the nodes are the bright lines and shadows and the arcs are the connections between bright lines and shadows. For the first technique, constraints based on angle of depression and the relationship between connected bright lines and shadows are applied to remove unrelated arcs. The second technique calculates weights for the connections and then performs a series of increasingly relaxed hard and soft thresholds. This results in groups of various levels on their validity. Once the related bright lines and shadows are grouped, their locations are combined to provide an approximate building location. Experimental results demonstrate the outcome of the two techniques. The two techniques are compared and discussed.

  13. Characterization of patterns formed by shadows of spheres.

    PubMed

    Kostinski, Sarah V; Chen, Elizabeth R; Brenner, Michael P

    2014-06-13

    Motivated by colloidal lithography, we study the problem of characterizing periodic planar patterns formed by shadows of spheres. The set of patterns accessible to shadow lithography spanned by lattice types, tilt, and rotation angles is rich, but topological considerations of shadow overlap along simplex edges and faces lead us to just 4+1 distinct categories. These planar patterns are in one-to-one correspondence with a 4-valued index linked to Cayley-Menger determinants. The characterization is confirmed by a phase diagram which predicts surface patterns for any experimental geometry. PMID:24972217

  14. Time step and shadow Hamiltonian in molecular dynamics simulations

    NASA Astrophysics Data System (ADS)

    Kim, Sangrak

    2015-08-01

    We examine the time step and the shadow Hamiltonian of symplectic algorithms for a bound system of a simple harmonic oscillator as a specific example. The phase space trajectory moves on the hyperplane of a constant shadow Hamiltonian. We find a stationary condition for the time step τ n with which the motion repeats itself on the phase space with a period n. Interestingly, that the time steps satisfying the stationary condition turn out to be independent of the symplectic algorithms chosen. Furthermore, the phase volume enclosed by the phase trajectory is given by n τ n Ẽ n , where Ẽ n is the initial shadow energy of the corresponding symplectic algorithm.

  15. Automatic detection method of lung cancers including ground-glass opacities from chest x-ray CT images

    NASA Astrophysics Data System (ADS)

    Ezoe, Toshiharu; Takizawa, Hotaka; Yamamoto, Shinji; Shimizu, Akinobu; Matsumoto, Tohru; Tateno, Yukio; Iimura, Takeshi; Matsumoto, Mitsuomi

    2002-05-01

    In this paper, we described an algorithm of automatic detection of ground glass opacities (GGO) from X-ray CT images. In this algorithm, at first, pathological shadow candidates are extracted by our variable N-Quoit filter which is a kind of mathematical morphology filter. Next, shadow candidates are classified into some classes using feature values calculated from the shadow candidates. By using discriminate functions, at last, shadow candidates are discriminated between normal shadows and abnormal ones. This method was examined by 38 samples (including GGO's shadows) of chest CT images, and proved to be very effective.

  16. Epilepsy (partial)

    PubMed Central

    2011-01-01

    Introduction About 3% of people will be diagnosed with epilepsy during their lifetime, but about 70% of people with epilepsy eventually go into remission. Methods and outcomes We conducted a systematic review and aimed to answer the following clinical questions: What are the effects of starting antiepileptic drug treatment following a single seizure? What are the effects of drug monotherapy in people with partial epilepsy? What are the effects of additional drug treatments in people with drug-resistant partial epilepsy? What is the risk of relapse in people in remission when withdrawing antiepileptic drugs? What are the effects of behavioural and psychological treatments for people with epilepsy? What are the effects of surgery in people with drug-resistant temporal lobe epilepsy? We searched: Medline, Embase, The Cochrane Library, and other important databases up to July 2009 (Clinical Evidence reviews are updated periodically; please check our website for the most up-to-date version of this review). We included harms alerts from relevant organisations such as the US Food and Drug Administration (FDA) and the UK Medicines and Healthcare products Regulatory Agency (MHRA). Results We found 83 systematic reviews, RCTs, or observational studies that met our inclusion criteria. We performed a GRADE evaluation of the quality of evidence for interventions. Conclusions In this systematic review we present information relating to the effectiveness and safety of the following interventions: antiepileptic drugs after a single seizure; monotherapy for partial epilepsy using carbamazepine, gabapentin, lamotrigine, levetiracetam, phenobarbital, phenytoin, sodium valproate, or topiramate; addition of second-line drugs for drug-resistant partial epilepsy (allopurinol, eslicarbazepine, gabapentin, lacosamide, lamotrigine, levetiracetam, losigamone, oxcarbazepine, retigabine, tiagabine, topiramate, vigabatrin, or zonisamide); antiepileptic drug withdrawal for people with partial or

  17. Partially Hydrated Electrons at the Air/Water Interface Observed by UV-Excited Time-Resolved Heterodyne-Detected Vibrational Sum Frequency Generation Spectroscopy.

    PubMed

    Matsuzaki, Korenobu; Kusaka, Ryoji; Nihonyanagi, Satoshi; Yamaguchi, Shoichi; Nagata, Takashi; Tahara, Tahei

    2016-06-22

    Hydrated electrons are the most fundamental anion species, consisting only of electrons and surrounding water molecules. Although hydrated electrons have been extensively studied in the bulk aqueous solutions, even their existence is still controversial at the water surface. Here, we report the observation and characterization of hydrated electrons at the air/water interface using new time-resolved interface-selective nonlinear vibrational spectroscopy. With the generation of electrons at the air/water interface by ultraviolet photoirradiation, we observed the appearance of a strong transient band in the OH stretch region by heterodyne-detected vibrational sum-frequency generation. Through the comparison with the time-resolved spectra at the air/indole solution interface, the transient band was assigned to the vibration of water molecules that solvate electrons at the interface. The analysis of the frequency and decay of the observed transient band indicated that the electrons are only partially hydrated at the water surface, and that they escape into the bulk within 100 ps. PMID:27281547

  18. Near-infrared Raman spectroscopy to detect anti-Toxoplasma gondii antibody in blood sera of domestic cats: quantitative analysis based on partial least-squares multivariate statistics

    NASA Astrophysics Data System (ADS)

    Duarte, Janaína; Pacheco, Marcos T. T.; Villaverde, Antonio Balbin; Machado, Rosangela Z.; Zângaro, Renato A.; Silveira, Landulfo

    2010-07-01

    Toxoplasmosis is an important zoonosis in public health because domestic cats are the main agents responsible for the transmission of this disease in Brazil. We investigate a method for diagnosing toxoplasmosis based on Raman spectroscopy. Dispersive near-infrared Raman spectra are used to quantify anti-Toxoplasma gondii (IgG) antibodies in blood sera from domestic cats. An 830-nm laser is used for sample excitation, and a dispersive spectrometer is used to detect the Raman scattering. A serological test is performed in all serum samples by the enzyme-linked immunosorbent assay (ELISA) for validation. Raman spectra are taken from 59 blood serum samples and a quantification model is implemented based on partial least squares (PLS) to quantify the sample's serology by Raman spectra compared to the results provided by the ELISA test. Based on the serological values provided by the Raman/PLS model, diagnostic parameters such as sensitivity, specificity, accuracy, positive prediction values, and negative prediction values are calculated to discriminate negative from positive samples, obtaining 100, 80, 90, 83.3, and 100%, respectively. Raman spectroscopy, associated with the PLS, is promising as a serological assay for toxoplasmosis, enabling fast and sensitive diagnosis.

  19. Testing General Relativity with the Shadow Size of Sgr A(*).

    PubMed

    Johannsen, Tim; Broderick, Avery E; Plewa, Philipp M; Chatzopoulos, Sotiris; Doeleman, Sheperd S; Eisenhauer, Frank; Fish, Vincent L; Genzel, Reinhard; Gerhard, Ortwin; Johnson, Michael D

    2016-01-22

    In general relativity, the angular radius of the shadow of a black hole is primarily determined by its mass-to-distance ratio and depends only weakly on its spin and inclination. If general relativity is violated, however, the shadow size may also depend strongly on parametric deviations from the Kerr metric. Based on a reconstructed image of Sagittarius A^{*} (Sgr A^{*}) from a simulated one-day observing run of a seven-station Event Horizon Telescope (EHT) array, we employ a Markov chain Monte Carlo algorithm to demonstrate that such an observation can measure the angular radius of the shadow of Sgr A^{*} with an uncertainty of ∼1.5  μas (6%). We show that existing mass and distance measurements can be improved significantly when combined with upcoming EHT measurements of the shadow size and that tight constraints on potential deviations from the Kerr metric can be obtained. PMID:26849580

  20. Overestimation of Mach number due to probe shadow

    NASA Astrophysics Data System (ADS)

    Gosselin, J. J.; Thakur, S. C.; Sears, S. H.; McKee, J. S.; Scime, E. E.; Tynan, G. R.

    2016-07-01

    Comparisons of the plasma ion flow speed measurements from Mach probes and laser induced fluorescence were performed in the Controlled Shear Decorrelation Experiment. We show the presence of the probe causes a low density geometric shadow downstream of the probe that affects the current density collected by the probe in collisional plasmas if the ion-neutral mean free path is shorter than the probe shadow length, Lg = w2 Vdrift/D⊥, resulting in erroneous Mach numbers. We then present a simple correction term that provides the corrected Mach number from probe data when the sound speed, ion-neutral mean free path, and perpendicular diffusion coefficient of the plasma are known. The probe shadow effect must be taken into account whenever the ion-neutral mean free path is on the order of the probe shadow length in linear devices and the open-field line region of fusion devices.

  1. Shadow noise in OCT images of biological tissues

    SciTech Connect

    Dolin, L S; Sergeeva, E A; Turchin, I V

    2008-06-30

    Optical coherence tomography (OCT) images of turbid medium with spatially fluctuating optical parameters demonstrate the presence of spatial noise ('shadow noise') caused by shading of the observed layer by variations in scattering and absorption coefficients of superficial layers. In this paper we report the development of the theoretical model of shadow noise in OCT images in which the features for discriminating this type of noise from the noise of a different origin are determined. Shadow noise is discovered in OCT images of biological tissue after specific image processing and the validity of the developed theoretical model is proven. The role of shadow noise as an interfering factor at imaging the variations in the backscattering coefficient, as well as the source of extra information on optical characteristics of the medium is analysed. (special issue devoted to application of laser technologies in biophotonics and biomedical studies)

  2. Movement of March 2016 Total Solar Eclipse Shadow (Animation)

    NASA Video Gallery

    The moon will pass in front of the sun, casting its shadow over much of Southeast Asia on March 8, 2016 EST (March 9 local time). People on the nearly 100-mile-wide path of totality will experience...

  3. INTERIOR OF WEST SPAN LOOKING WEST (SHADOW OF VERTICAL LAPS ...

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

    INTERIOR OF WEST SPAN LOOKING WEST (SHADOW OF VERTICAL LAPS PLACED ON ZONE III; ASPHALT ZONE IX) - Honey Run Bridge, Spanning Butte Creek, bypassed section of Honey Run Road (originally Carr Hill Road), Paradise, Butte County, CA

  4. Testing General Relativity with the Shadow Size of Sgr A*

    NASA Astrophysics Data System (ADS)

    Johannsen, Tim; Broderick, Avery E.; Plewa, Philipp M.; Chatzopoulos, Sotiris; Doeleman, Sheperd S.; Eisenhauer, Frank; Fish, Vincent L.; Genzel, Reinhard; Gerhard, Ortwin; Johnson, Michael D.

    2016-01-01

    In general relativity, the angular radius of the shadow of a black hole is primarily determined by its mass-to-distance ratio and depends only weakly on its spin and inclination. If general relativity is violated, however, the shadow size may also depend strongly on parametric deviations from the Kerr metric. Based on a reconstructed image of Sagittarius A* (Sgr A* ) from a simulated one-day observing run of a seven-station Event Horizon Telescope (EHT) array, we employ a Markov chain Monte Carlo algorithm to demonstrate that such an observation can measure the angular radius of the shadow of Sgr A* with an uncertainty of ˜1.5 μ as (6%). We show that existing mass and distance measurements can be improved significantly when combined with upcoming EHT measurements of the shadow size and that tight constraints on potential deviations from the Kerr metric can be obtained.

  5. Influence of Earth's Shadowing Effects on Space Debris Stability

    NASA Astrophysics Data System (ADS)

    Hubaux, C.

    2013-08-01

    In this work, we present results about the stability of near geosynchronous space debris characterized by high area-to-mass ratios. We extend previous studies by considering the influence of the Earth's shadow on the short-and long-term time evolutions. To assess the orbits stability, we use the Global Symplectic Integrator (GSI) [18] which consists in the symplectic integration of both Hamiltonian equations of motion and variational equations. The solution of the variational equations is then used to compute the Mean Exponential Growth factor of Nearby Orbits (MEGNO) chaos indicator. The effects of the Earth's shadow are analyzed using the adapted conical and cylindrical Earth's shadowing models introduced by [10]. Our stability study shows that the Earth's shadow greatly affects the global behaviour of space debris orbits by increasing the size of chaotic regions around the geostationary altitude.

  6. Shift of the shadow boundary in high frequency scattering

    NASA Astrophysics Data System (ADS)

    Zworski, Maciej

    1991-02-01

    The microlocal theory of diffraction is used to establish the conjecture of Keller and Rubinow relating the shift of the shadow boundary in high frequency scattering to the directional curvatures of a strictly convex obstacle.

  7. 'Marsshine' on Shadowed Part of Phobos

    NASA Technical Reports Server (NTRS)

    2008-01-01

    [figure removed for brevity, see original site] Inset

    The High Resolution Imaging Science Experiment (HiRISE) camera on NASA's Mars Reconnaissance Orbiter took two images of the larger of Mars' two moons, Phobos, within 10 minutes of each other on March 23, 2008. This is a portion of the second one, enhanced to bring out detail in areas of Phobos that were not illuminated by the sun when the image was taken. Craters are visible due to faint illumination from reflected light off of Mars ('Marsshine'). This is directly analogous to 'Earthshine,' the reflected sunlight from our planet that illuminates the dark side of Earth's moon. The enhancement to show details in the shadows also washes out detail in the sunlit areas in the lower portion of the image.

    The ability to see features on Phobos illuminated by Marsshine demonstrates the high sensitivity of the HiRISE camera. This image is in the HiRISE catalog as PSP_007769_9015.

    NASA's Jet Propulsion Laboratory, a division of the California Institute of Technology in Pasadena, manages the Mars Reconnaissance Orbiter for NASA's Science Mission Directorate, Washington. Lockheed Martin Space Systems, Denver, is the prime contractor for the project and built the spacecraft. The High Resolution Imaging Science Experiment is operated by the University of Arizona, Tucson, and the instrument was built by Ball Aerospace & Technologies Corp., Boulder, Colo.

  8. Island shadows in wave directional spectra

    NASA Astrophysics Data System (ADS)

    Pawka, S. S.

    1983-03-01

    Shadows of individual islands are observed in directional spectra sampled with a high resolution linear array at Torrey Pines Beach, California. A detailed investigation of the spectra indicates that the Channel Islands restrict the wave energy density to certain narrow directional sectors. A deep spectral trough, associated with San Clemente Island, is a predominant feature in the well resolved spectra (wave frequencies ˜0.06-0.15 Hz). Negligible values of energy density in the center of this directional `gap' were consistently observed in the range 0.082-0.114 Hz. Measurable but low gap energy density values are seen in the high and low frequency regimes. Generation of high frequency waves (f≥0.13 Hz) by local winds generally smears the island windowing effects and even creates a spectral peak in a directional sector which is blocked from deep ocean exposure. Several estimation techniques are used in the directional spectrum analysis. These include the Maximum Likelihood Method (MLM) and two methods developed in this work. The two new techniques show significant improvement over the MLM in the definition of gaps in the spectrum. Although none of these methods is considered an `Optimal' estimator for general use, each displays some superior merit in particular directional spectrum estimation problems.

  9. Phoenix Conductivity Probe with Shadow and Toothmark

    NASA Technical Reports Server (NTRS)

    2008-01-01

    NASA's Phoenix Mars Lander inserted the four needles of its thermal and conductivity probe into Martian soil during the 98th Martian day, or sol, of the mission and left it in place until Sol 99 (Sept. 4, 2008).

    The Robotic Arm Camera on Phoenix took this image on the morning of Sol 99 after the probe was lifted away from the soil. The imprint left by the insertion is visible below the probe, and a shadow showing the probe's four needles is cast on a rock to the left.

    The thermal and conductivity probe measures how fast heat and electricity move from one needle to an adjacent one through the soil or air between the needles. Conductivity readings can be indicators about water vapor, water ice and liquid water.

    The probe is part of Phoenix's Microscopy, Electrochemistry and Conductivity suite of instruments.

    The Phoenix Mission is led by the University of Arizona, Tucson, on behalf of NASA. Project management of the mission is by NASA's Jet Propulsion Laboratory, Pasadena, Calif. Spacecraft development is by Lockheed Martin Space Systems, Denver.

  10. The multisensory body revealed through its cast shadows.

    PubMed

    Pavani, Francesco; Galfano, Giovanni

    2015-01-01

    One key issue when conceiving the body as a multisensory object is how the cognitive system integrates visible instances of the self and other bodies with one's own somatosensory processing, to achieve self-recognition and body ownership. Recent research has strongly suggested that shadows cast by our own body have a special status for cognitive processing, directing attention to the body in a fast and highly specific manner. The aim of the present article is to review the most recent scientific contributions addressing how body shadows affect both sensory/perceptual and attentional processes. The review examines three main points: (1) body shadows as a special window to investigate the construction of multisensory body perception; (2) experimental paradigms and related findings; (3) open questions and future trajectories. The reviewed literature suggests that shadows cast by one's own body promote binding between personal and extrapersonal space and elicit automatic orienting of attention toward the body-part casting the shadow. Future research should address whether the effects exerted by body shadows are similar to those observed when observers are exposed to other visual instances of their body. The results will further clarify the processes underlying the merging of vision and somatosensation when creating body representations. PMID:26042079

  11. Shadows of Kerr Black Holes with Scalar Hair.

    PubMed

    Cunha, Pedro V P; Herdeiro, Carlos A R; Radu, Eugen; Rúnarsson, Helgi F

    2015-11-20

    Using backwards ray tracing, we study the shadows of Kerr black holes with scalar hair (KBHSH). KBHSH interpolate continuously between Kerr BHs and boson stars (BSs), so we start by investigating the lensing of light due to BSs. Moving from the weak to the strong gravity region, BSs-which by themselves have no shadows-are classified, according to the lensing produced, as (i) noncompact, which yield not multiple images, (ii) compact, which produce an increasing number of Einstein rings and multiple images of the whole celestial sphere, and (iii) ultracompact, which possess light rings, yielding an infinite number of images with (we conjecture) a self-similar structure. The shadows of KBHSH, for Kerr-like horizons and noncompact BS-like hair, are analogous to, but distinguishable from, those of comparable Kerr BHs. But for non-Kerr-like horizons and ultracompact BS-like hair, the shadows of KBHSH are drastically different: novel shapes arise, sizes are considerably smaller, and multiple shadows of a single BH become possible. Thus, KBHSH provide quantitatively and qualitatively new templates for ongoing (and future) very large baseline interferometry observations of BH shadows, such as those of the Event Horizon Telescope. PMID:26636837

  12. The multisensory body revealed through its cast shadows

    PubMed Central

    Pavani, Francesco; Galfano, Giovanni

    2015-01-01

    One key issue when conceiving the body as a multisensory object is how the cognitive system integrates visible instances of the self and other bodies with one’s own somatosensory processing, to achieve self-recognition and body ownership. Recent research has strongly suggested that shadows cast by our own body have a special status for cognitive processing, directing attention to the body in a fast and highly specific manner. The aim of the present article is to review the most recent scientific contributions addressing how body shadows affect both sensory/perceptual and attentional processes. The review examines three main points: (1) body shadows as a special window to investigate the construction of multisensory body perception; (2) experimental paradigms and related findings; (3) open questions and future trajectories. The reviewed literature suggests that shadows cast by one’s own body promote binding between personal and extrapersonal space and elicit automatic orienting of attention toward the body-part casting the shadow. Future research should address whether the effects exerted by body shadows are similar to those observed when observers are exposed to other visual instances of their body. The results will further clarify the processes underlying the merging of vision and somatosensation when creating body representations. PMID:26042079

  13. Oxygen partial pressure sensor

    DOEpatents

    Dees, D.W.

    1994-09-06

    A method for detecting oxygen partial pressure and an oxygen partial pressure sensor are provided. The method for measuring oxygen partial pressure includes contacting oxygen to a solid oxide electrolyte and measuring the subsequent change in electrical conductivity of the solid oxide electrolyte. A solid oxide electrolyte is utilized that contacts both a porous electrode and a nonporous electrode. The electrical conductivity of the solid oxide electrolyte is affected when oxygen from an exhaust stream permeates through the porous electrode to establish an equilibrium of oxygen anions in the electrolyte, thereby displacing electrons throughout the electrolyte to form an electron gradient. By adapting the two electrodes to sense a voltage potential between them, the change in electrolyte conductivity due to oxygen presence can be measured. 1 fig.

  14. Oxygen partial pressure sensor

    DOEpatents

    Dees, Dennis W.

    1994-01-01

    A method for detecting oxygen partial pressure and an oxygen partial pressure sensor are provided. The method for measuring oxygen partial pressure includes contacting oxygen to a solid oxide electrolyte and measuring the subsequent change in electrical conductivity of the solid oxide electrolyte. A solid oxide electrolyte is utilized that contacts both a porous electrode and a nonporous electrode. The electrical conductivity of the solid oxide electrolyte is affected when oxygen from an exhaust stream permeates through the porous electrode to establish an equilibrium of oxygen anions in the electrolyte, thereby displacing electrons throughout the electrolyte to form an electron gradient. By adapting the two electrodes to sense a voltage potential between them, the change in electrolyte conductivity due to oxygen presence can be measured.

  15. Change detection of land use and land cover in an urban region with SPOT-5 images and partial Lanczos extreme learning machine

    NASA Astrophysics Data System (ADS)

    Chang, Ni-Bin; Han, Min; Yao, Wei; Chen, Liang-Chien; Xu, Shiguo

    2010-11-01

    Satellite remote sensing technology and the science associated with evaluation of land use and land cover (LULC) in an urban region makes use of the wide range images and algorithms. Improved land management capacity is critically dependent on real-time or near real-time monitoring of land-use/land cover change (LUCC) to the extent to which solutions to a whole host of urban/rural interface development issues may be well managed promptly. Yet previous processing with LULC methods is often time-consuming, laborious, and tedious making the outputs unavailable within the required time window. This paper presents a new image classification approach based on a novel neural computing technique that is applied to identify the LULC patterns in a fast growing urban region with the aid of 2.5-meter resolution SPOT-5 image products. The classifier was constructed based on the partial Lanczos extreme learning machine (PL-ELM), which is a novel machine learning algorithm with fast learning speed and outstanding generalization performance. Since some different classes of LULC may be linked with similar spectral characteristics, texture features and vegetation indexes were extracted and included during the classification process to enhance the discernability. A validation procedure based on ground truth data and comparisons with some classic classifiers prove the credibility of the proposed PL-ELM classification approach in terms of the classification accuracy as well as the processing speed. A case study in Dalian Development Area (DDA) with the aid of the SPOT-5 satellite images collected in the year of 2003 and 2007 and PL-ELM fully supports the monitoring needs and aids in the rapid change detection with respect to both urban expansion and coastal land reclamations.

  16. Partial least squares analysis of rocket propulsion fuel data using diaphragm valve-based comprehensive two-dimensional gas chromatography coupled with flame ionization detection.

    PubMed

    Freye, Chris E; Fitz, Brian D; Billingsley, Matthew C; Synovec, Robert E

    2016-06-01

    The chemical composition and several physical properties of RP-1 fuels were studied using comprehensive two-dimensional (2D) gas chromatography (GC×GC) coupled with flame ionization detection (FID). A "reversed column" GC×GC configuration was implemented with a RTX-wax column on the first dimension ((1)D), and a RTX-1 as the second dimension ((2)D). Modulation was achieved using a high temperature diaphragm valve mounted directly in the oven. Using leave-one-out cross-validation (LOOCV), the summed GC×GC-FID signal of three compound-class selective 2D regions (alkanes, cycloalkanes, and aromatics) was regressed against previously measured ASTM derived values for these compound classes, yielding root mean square errors of cross validation (RMSECV) of 0.855, 0.734, and 0.530mass%, respectively. For comparison, using partial least squares (PLS) analysis with LOOCV, the GC×GC-FID signal of the entire 2D separations was regressed against the same ASTM values, yielding a linear trend for the three compound classes (alkanes, cycloalkanes, and aromatics), yielding RMSECV values of 1.52, 2.76, and 0.945 mass%, respectively. Additionally, a more detailed PLS analysis was undertaken of the compounds classes (n-alkanes, iso-alkanes, mono-, di-, and tri-cycloalkanes, and aromatics), and of physical properties previously determined by ASTM methods (such as net heat of combustion, hydrogen content, density, kinematic viscosity, sustained boiling temperature and vapor rise temperature). Results from these PLS studies using the relatively simple to use and inexpensive GC×GC-FID instrumental platform are compared to previously reported results using the GC×GC-TOFMS instrumental platform. PMID:27130110

  17. Image processing system and method for recognizing and removing shadows from the image of a monitored scene

    DOEpatents

    Osbourn, Gordon C.

    1996-01-01

    The shadow contrast sensitivity of the human vision system is simulated by configuring information obtained from an image sensor so that the information may be evaluated with multiple pixel widths in order to produce a machine vision system able to distinguish between shadow edges and abrupt object edges. A second difference of the image intensity for each line of the image is developed and this second difference is used to screen out high frequency noise contributions from the final edge detection signals. These edge detection signals are constructed from first differences of the image intensity where the screening conditions are satisfied. The positional coincidence of oppositely signed maxima in the first difference signal taken from the right and the second difference signal taken from the left is used to detect the presence of an object edge. Alternatively, the effective number of responding operators (ENRO) may be utilized to determine the presence of object edges.

  18. Shadowing the Circular Restricted Three-Body Orbits

    NASA Astrophysics Data System (ADS)

    Zhu, Yong-Kang; Hayes, W. B.

    2009-05-01

    The circular restricted three-body problem (CRTBP) is a celebrated problem in which Poincare first derived the existence of chaos. In chaotic systems, nearby trajectories diverge exponentially away from each other. This implies that numerical errors become exponentially magnified, degrading the reliability of numerical solutions. Confidence in the reliability of numerical solutions can be increased using shadowing. A shadow is an exact trajectory that stays close to a numerical one for a long time, validating the dynamics observed in the numerical solution. To find shadows, we use a refinement algorithm similar a Newton's method (Hayes and Jackson 2007). Murison (1989) used an extremely accurate, high cost integrator to observe fractal structure in a capture-time diagram in the CRTBP. We can reproduce this structure using much cheaper integrations, and demonstrate that most of the cheap trajectories are shadowed. We also observe a negative correlation between capture time and shadow length. We surmise that this is because the dynamical time for orbits around the smaller massive particle in the CRTBP is much shorter than dynamical time around the larger (eg., the Moon's orbital period around the Earth is much shorter than the Earth's orbital period around the Sun), and it has been observed(Hayes 2003) that shadow lengths tend to scale linearly with dynamical times. However, in this study we also found many orbits with very long capture time (Moon-like orbits) which were shadowable for long periods, indicating that such stable orbits were reliably integrated. Thus, we are able to verify the reliability of most short capture time orbits, but are unable to verify the reliability of a significant proportion of long-capture-time orbits.

  19. Did photosynthetic organisms take refuge in ice shadows during Snowball Earth events?

    NASA Astrophysics Data System (ADS)

    Campbell, A. J.; Warren, S. G.; Waddington, E. D.

    2014-12-01

    During the Snowball Earth glaciations of the Neoproterozoic, the Earth's oceans may have been completely covered with ice. Global ice cover, thick enough to block the transmission of light, would have prohibited the survival of photosynthetic eukaryotic organisms living under the ice cover. Fossil records indicate these organisms persisted during the Snowball Earth glaciations. The persistence of these organisms presents a complication to the Snowball Earth theory. If the Earth's oceans were unable to survive in planet's ocean during the Snowball Earth events, then in what environments did these organisms survive? Previously, our research has shown that narrow arms of the ocean, analogous to the modern Red Sea, could have been refugia for photosynthetic eukaryotes during Snowball Earth events. We have demonstrated that for a limited range of climate conditions, ice flow into an arm of the sea is restricted sufficiently to allow for the sea to remain partially free from sea-glacier penetration, a necessary condition for these regions to act as a refugia for photosynthetic eukaryotes during a Snowball Earth event. Presently, we demonstrate that thin-ice zones can form on the leeward sides of obstructions in channels. These thin-ice zones, which we call ice shadows, may have acted as refugia for photosynthetic eukaryotes during Snowball Earth events. We test the ability of ice shadows to form in channels where, in the absence of an obstruction, sea-glacier ice would be thick enough to prohibit the transmission of light. We find that ice shadows can form behind obstructions of various sizes and over a range of climate conditions. This research adds to the range of environments where photosynthetic eukaryotes may have survived during the Snowball Earth events.

  20. Electromagnetic penetration through narrow slots in conducting surfaces and coupling to structures on the shadow side

    SciTech Connect

    Reed, E.K.; Butler, C.M. . Dept. of Electrical and Computer Engineering)

    1990-07-01

    Electromagnetic field penetration through a curved narrow slot in a planar conducting surface and coupling to a curved, loaded thin wire on the shadow side are determined in the time domain (TD) and the frequency domain (FD) by integral equation methods. Coupled integral equations are derived and solved numerically for the equivalent magnetic current in the slot and the electric current on the wire, from which the field that penetrates the slotted surface is determined. One employs a piecewise linear approximation of the unknown currents and performs equation enforcement by pulse testing. The resulting TD equations are solved by a scheme incorporating a finite-difference approximation for a second partial time derivative which allows one to solve for the unknown currents at a discrete time instant t + 1 in terms of the known excitation and currents calculated at a discrete time instant t and earlier. The FD equations are solved by the method of moments. A hybrid time-domain integral equation -- finite-difference time-domain solution technique is described whereby one solves for the field which penetrates a slotted cavity-backed surface. One models the fields in the exterior region and in the slot with integral operators and models the fields inside the cavity with a discretized form of Maxwell's equations. Narrow slots following various contours were chemically etched in thin bass sheets and an apparatus was fabricated to measure shadow-side fields, electric current on a thin wire on the shadow side, and, separately, fields inside a rectangular cavity which backed the slotted brass sheet. The experimentation was conducted at the Lawrence Livermore National Laboratory on a frequency-domain test range employing a monocone source over a large ground plane. One observes very good agreement among the experimental and theoretical results.

  1. Shadowing of gluons in perturbative QCD: A comparison of different models

    SciTech Connect

    Jalilian-Marian, Jamal; Wang, Xin-Nian

    2001-05-01

    We investigate the different perturbative QCD-based models for nuclear shadowing of gluons. We show that, in the kinematic region appropriate to the BNL relativistic heavy ion collider experiment, all models give similar estimates for the magnitude of gluon shadowing. At scales relevant to CERN large hadron collider (LHC), there is a sizable difference between the predictions of the different models. However, the uncertainties in gluon shadowing coming from a different parametrization of the gluon distribution in nucleons, are larger than those due to different perturbative QCD models of gluon shadowing. We also investigate the effect of initial nonperturbative shadowing on the magnitude of perturbative shadowing and show that the magnitudes of perturbative and nonperturbative shadowing are comparable at RHIC but perturbative shadowing dominates over nonperturbative shadowing at smaller values of x reached at LHC.

  2. Angular resolution studies of the CYGNUS array using the shadows of the sun and moon

    SciTech Connect

    Shoup, A.L.; The CYGNUS Collaboration

    1993-05-01

    Using the cosmic ray shadows of the sun and moon, we have estimated the angular resolution of the CYGNUS extensive air shower array. With the event sample now available we estimate the angular resolution of the array to be 0.70{sub {minus}0.06}{sup {plus}0.07} degrees. The resolution depends on the total number of detected shower particles. A new parameterization of the measured shower-front timing structure and the use of counters with small pulse areas lead to a {approximately}25% improvement in the resolution. The systematic pointing error of the array is less than 0.4{degree}.

  3. Angular resolution studies of the CYGNUS array using the shadows of the sun and moon

    SciTech Connect

    Shoup, A.L.

    1993-01-01

    Using the cosmic ray shadows of the sun and moon, we have estimated the angular resolution of the CYGNUS extensive air shower array. With the event sample now available we estimate the angular resolution of the array to be 0.70[sub [minus]0.06][sup [plus]0.07] degrees. The resolution depends on the total number of detected shower particles. A new parameterization of the measured shower-front timing structure and the use of counters with small pulse areas lead to a [approximately]25% improvement in the resolution. The systematic pointing error of the array is less than 0.4[degree].

  4. How much imitation is there in a shadowing task?

    PubMed Central

    Dufour, Sophie; Nguyen, Noël

    2013-01-01

    Phonetic imitation, also called phonetic convergence, is currently at the heart of numerous investigations since it can inform us on both the nature of lexical representations and the link between production and perception processes in spoken language communication. A task that has been largely used to study phonetic imitation is the shadowing task, in which participants merely listen to and repeat isolated words. In this study, we examined the extent to which the phonetic convergence effect found when participants shadow auditory tokens, is an imitation of the speaker. We thus compared the phonetic convergence effect observed in a shadowing task to that observed when participants were explicitly instructed to imitate the productions they were exposed to. Although the phonetic convergence effect was greater when participants intentionally imitated the speaker's productions, shadowing and imitation instructions led to the same degree of convergence in a post-exposure task. Hence, the convergence effect found in a shadowing task and that found in an imitation task seem to share a general mechanism which is automatic and which taps into the long-term representations of the words in memory. At a more theoretical level, our results reinforce the claim that detailed auditory traces associated with perceived words are stored in memory and are later used for production. PMID:23801974

  5. The Interrupted Power Law and the Size of Shadow Banking

    PubMed Central

    Fiaschi, Davide; Kondor, Imre; Marsili, Matteo; Volpati, Valerio

    2014-01-01

    Using public data (Forbes Global 2000) we show that the asset sizes for the largest global firms follow a Pareto distribution in an intermediate range, that is “interrupted” by a sharp cut-off in its upper tail, where it is totally dominated by financial firms. This flattening of the distribution contrasts with a large body of empirical literature which finds a Pareto distribution for firm sizes both across countries and over time. Pareto distributions are generally traced back to a mechanism of proportional random growth, based on a regime of constant returns to scale. This makes our findings of an “interrupted” Pareto distribution all the more puzzling, because we provide evidence that financial firms in our sample should operate in such a regime. We claim that the missing mass from the upper tail of the asset size distribution is a consequence of shadow banking activity and that it provides an (upper) estimate of the size of the shadow banking system. This estimate–which we propose as a shadow banking index–compares well with estimates of the Financial Stability Board until 2009, but it shows a sharper rise in shadow banking activity after 2010. Finally, we propose a proportional random growth model that reproduces the observed distribution, thereby providing a quantitative estimate of the intensity of shadow banking activity. PMID:24728096

  6. Very narrow shadow extra Z boson at colliders

    SciTech Connect

    Chang, W.-F.; Ng, John N.; Wu, Jackson M. S.

    2006-11-01

    We consider the phenomenological consequences of a hidden Higgs sector extending the standard model (SM), in which the 'shadow Higgs' are uncharged under the SM gauge groups. We consider a simple U(1) model with one Higgs singlet. One mechanism which sheds light on the shadow sector is the mixing between the neutral gauge boson of the SM and the additional U(1) gauge group. The mixing happens through the usual mass mixing and also kinetic mixing, and is the only way the 'shadow Z' couples to the SM. We study in detail modifications that the presence of such shadow sector would bring to the electroweak precision tests, which in turn provide constraints on the kinetic-mixing parameter, s{sub {epsilon}}, left free in our model. The shadow Z production rate at the CERN LHC and the International Linear Collider depends on s{sub {epsilon}}. We find that the observable event rate at both facilities is possible for a reasonable range of s{sub {epsilon}} allowed by electroweak precision tests.

  7. The interrupted power law and the size of shadow banking.

    PubMed

    Fiaschi, Davide; Kondor, Imre; Marsili, Matteo; Volpati, Valerio

    2014-01-01

    Using public data (Forbes Global 2000) we show that the asset sizes for the largest global firms follow a Pareto distribution in an intermediate range, that is "interrupted" by a sharp cut-off in its upper tail, where it is totally dominated by financial firms. This flattening of the distribution contrasts with a large body of empirical literature which finds a Pareto distribution for firm sizes both across countries and over time. Pareto distributions are generally traced back to a mechanism of proportional random growth, based on a regime of constant returns to scale. This makes our findings of an "interrupted" Pareto distribution all the more puzzling, because we provide evidence that financial firms in our sample should operate in such a regime. We claim that the missing mass from the upper tail of the asset size distribution is a consequence of shadow banking activity and that it provides an (upper) estimate of the size of the shadow banking system. This estimate-which we propose as a shadow banking index-compares well with estimates of the Financial Stability Board until 2009, but it shows a sharper rise in shadow banking activity after 2010. Finally, we propose a proportional random growth model that reproduces the observed distribution, thereby providing a quantitative estimate of the intensity of shadow banking activity. PMID:24728096

  8. A separable shadow Hamiltonian hybrid Monte Carlo method

    NASA Astrophysics Data System (ADS)

    Sweet, Christopher R.; Hampton, Scott S.; Skeel, Robert D.; Izaguirre, Jesús A.

    2009-11-01

    Hybrid Monte Carlo (HMC) is a rigorous sampling method that uses molecular dynamics (MD) as a global Monte Carlo move. The acceptance rate of HMC decays exponentially with system size. The shadow hybrid Monte Carlo (SHMC) was previously introduced to reduce this performance degradation by sampling instead from the shadow Hamiltonian defined for MD when using a symplectic integrator. SHMC's performance is limited by the need to generate momenta for the MD step from a nonseparable shadow Hamiltonian. We introduce the separable shadow Hamiltonian hybrid Monte Carlo (S2HMC) method based on a formulation of the leapfrog/Verlet integrator that corresponds to a separable shadow Hamiltonian, which allows efficient generation of momenta. S2HMC gives the acceptance rate of a fourth order integrator at the cost of a second-order integrator. Through numerical experiments we show that S2HMC consistently gives a speedup greater than two over HMC for systems with more than 4000 atoms for the same variance. By comparison, SHMC gave a maximum speedup of only 1.6 over HMC. S2HMC has the additional advantage of not requiring any user parameters beyond those of HMC. S2HMC is available in the program PROTOMOL 2.1. A Python version, adequate for didactic purposes, is also in MDL (http://mdlab.sourceforge.net/s2hmc).

  9. The shadow of Saturn's icy satellites in the E ring

    NASA Astrophysics Data System (ADS)

    Schmidt, J.; Sremcevic, M.

    2008-09-01

    We analyze shadows that Saturnian satellites cast in the E ring, a faint, broad dust ring composed of icy grains. The brightness contrast of a moon's shadow relative to the surrounding ring allows to infer local properties of the size distribution of ring particles. We derive the shadow contrast from a large number of Cassini images of Enceladus taken in various filters in a range of phase angles 144 to 164 degrees. For Tethys and Dione we identify a clear shadow in images with phase angles larger than 160 degrees. From the data we obtain the number density of E ring grains at the orbits of Tethys and Dione relative to the one near Enceladus. The latter we constrain from the variation of the shadow contrast with color and phase angle. From the Enceladus data we construct the phase curve of the E ring dust between 144 and 164 degrees. We compare to data obtained from Earth-bound observations by de Pater et al 2004 and in situ measurements by the Cosmic Dust Analyzer onboard Cassini.

  10. eShadow: A tool for comparing closely related sequences

    SciTech Connect

    Ovcharenko, Ivan; Boffelli, Dario; Loots, Gabriela G.

    2004-01-15

    Primate sequence comparisons are difficult to interpret due to the high degree of sequence similarity shared between such closely related species. Recently, a novel method, phylogenetic shadowing, has been pioneered for predicting functional elements in the human genome through the analysis of multiple primate sequence alignments. We have expanded this theoretical approach to create a computational tool, eShadow, for the identification of elements under selective pressure in multiple sequence alignments of closely related genomes, such as in comparisons of human to primate or mouse to rat DNA. This tool integrates two different statistical methods and allows for the dynamic visualization of the resulting conservation profile. eShadow also includes a versatile optimization module capable of training the underlying Hidden Markov Model to differentially predict functional sequences. This module grants the tool high flexibility in the analysis of multiple sequence alignments and in comparing sequences with different divergence rates. Here, we describe the eShadow comparative tool and its potential uses for analyzing both multiple nucleotide and protein alignments to predict putative functional elements. The eShadow tool is publicly available at http://eshadow.dcode.org/

  11. A source of illumination for low-noise ‘Violin-Mode’ shadow sensors, intended for use in interferometric gravitational wave detectors

    NASA Astrophysics Data System (ADS)

    Lockerbie, N. A.; Tokmakov, K. V.; Strain, K. A.

    2014-12-01

    A low-noise source of illumination is described for shadow sensors having a displacement sensitivity of (69  ±  13) picometres (rms)/√Hz, at 500 Hz, over a measuring span of ±0.1 mm. These sensors were designed to detect ‘Violin-Mode’ resonances in the suspension fibres of the test-masses/mirrors for the Advanced LIGO (Laser Interferometer Gravitational wave Observatory) gravitational wave detectors. The source of illumination (emitter) described here used a single column of 8 × miniature near infrared LEDs (λ = 890 nm). These emitters cast the shadows of 400 μm diameter fused silica suspension fibres onto their complementary shadow-displacement detectors, located at a distance of 74 fibre diameters (29.6 mm) behind the axes of the fibres themselves. Violin-Mode vibrations of each fibre were sensed as differential ac photocurrents in the corresponding ‘split-photodiode’ detector. This paper describes the design, construction, noise analysis, and measures that were taken in the conception of the emitters, in order to produce high-contrast shadows at such distant detectors. In this way it proved possible to obtain, simultaneously, a very high transfer sensitivity to Violin-Mode vibration of the fibres, and a very low level of detection noise—close to the fundamental shot noise limit—whilst remaining within the constraints of this simple design of emitter. The shadow detector is described in an accompanying paper.

  12. Microphotometry of underwater shadowing by a moss from a Niagara Escarpment waterfall.

    PubMed

    Swatland, Howard J

    2011-02-01

    Microscope and fiber-optic spectrophotometry of transmittance and backscattering both showed moss leaves to be capable of casting strong shadows, with a single leaf blocking approximately 90% of incident light from a point source. In leaves with only one layer of cells, the transmittance through the cytoplasm of single cells was similar to that for whole leaves. Analysis of cell wall birefringence by polarized-light interferometry indicated that cell walls might normally scatter rather than transmit light. Spectra transmitted through, or backscattered from, the upper green layers of moss were dominated by selective absorbance from chlorophyll, but there was also evidence of wavelength-dependent scattering, as detected in the lower layers of brown, dead moss. Specular reflectance from moss leaves was detected by polarimetry and may have contributed to the relatively high macroscopic transmittance of stationary moss in water. Shadowing by moss leaves was confirmed by dynamic measurements of mosses in turbulent water without bubbles. Flicker patterns from leaves were superimposed on the underwater flicker pattern created at the air-water interface, thus flecks of light were reduced in intensity, increased in frequency, and decreased in duration. This was detected with both point source and diffuse illumination of samples. PMID:21087549

  13. ImERSE (Improving Experience through Regular Shadowing Events)

    PubMed Central

    Calvert, William; Minford, Joanne; Platt, Carol; Chatfield, Catriona

    2015-01-01

    Systematic operational quality improvement strategies within the NHS are hard to find, although there are numerous published reports of sporadic departmental models and methods resulting in improvements in clinical care. We describe the experience of devising a tool to provide large data collection of patient care experiences by using medical students to shadow patient journeys. This combines patient and family centred care (PFCC) and quality improvement approaches to create a systematic organisational strategy for improving care. The ImERSE (improving experience through regular shadowing events) approach could be applied to any area of health care to generate population specific improvement priorities. It can be used to promote patient and family centred care and provide a unique medical education experience. We describe its evolution in its first year of use and suggest that using the ImERSE approach delivers beneficial characteristics to patients and their families, those undergoing a shadowing experience, and provider organisations. PMID:26734410

  14. Shading and shadowing on Canaletto's Piazza San Marco

    NASA Astrophysics Data System (ADS)

    Wijntjes, Maarten W. A.; de Ridder, Huib

    2014-02-01

    Whereas the 17th century painter Canaletto was a master in linear perspective of the architectural elements, he seems to have had considerable difficulty with linear perspective of shadows. A common trick to avoid shadow perspective problems is to set the (solar) illumination direction parallel to the projection screen. We investigated in one painting where Canaletto clearly used this trick, whether he followed this light direction choice consistently through in how he shades the persons. We approached this question with a perceptual experiment where we measured perceived light directions in isolated details of the paintings. Specifically, we controlled whether observers could only see the (cast) shadow, only shading or both. We found different trends in all three conditions. The results indicate that Canaletto probably used different shading than the parallel light direction would predict. We interpret the results as a form or artistic freedom that Canaletto used to shade the persons individually.

  15. Further explorations of cosmogonic shadow effects in the Saturnian rings

    NASA Technical Reports Server (NTRS)

    Alfven, H.; Axnaes, I.; Brenning, N.; Lindqvist, P. A.

    1985-01-01

    The mass distribution in the Saturnian ring system is compared with predictions from the cosmogonic theory of Alfven and Arrhenius (1975) in which matter in the rings was once a magnetized plasma, with gravitation balanced by centrifugal force and by the magnetic field. As the plasma is neutralized, the magnetic force disappears and the matter can be shown to fall in to a distance 2/3 of the original. This supports the cosmogonic shadow effect, also demonstrated for the astroidal belt and in the large scale structure of the Saturnian ring system. The relevance of the comogonic shadow effect for parts of the finer structures of the Saturnian ring system is investigated. It is shown that many structures of the present ring system can be understood as shadows and antishadows of cosmogonic origin. These appear in the form of double rings centered around a position a factor 0.64 (slightly 2/3) closer to Saturn than the causing feature.

  16. Tree Leaf Shadows to the Sun's Density: A Surprising Route

    NASA Astrophysics Data System (ADS)

    Mallmann, A. James

    2013-01-01

    Rays of sunlight that strike raindrops produce rainbows that provide information about the spectrum of sunlight. Rays of sunlight that strike airborne ice crystals produce halos, sun pillars, and many other patterns of light and color in the sky. Analysis of those patterns makes it possible to determine the types and orientations of the ice crystals. Rays of sunlight that strike opaque objects produce shadow patterns that can be seen on any clear day. I was surprised to discover that the shadow patterns produced when sunlight strikes tree leaves provide all the information needed to determine the average density of the Sun. It seems unlikely that the Sun's density could be determined without knowing its mass or its volume. And, although it may seem even more unlikely, the density of the Sun can be determined using only information available in the shadows of tree leaves.

  17. Microbial flora of in-use, display eye shadow testers and bacterial challenges of unused eye shadows.

    PubMed Central

    Dawson, N L; Reinhardt, D J

    1981-01-01

    We surveyed 15 different brands of eye shadow on display for customer use in different retail stores for microbial contamination. This was the first reported microbial surveillance of in-use eye shadow display testers in retail establishments. Cultures were obtained at each retail store. Sterile dacron swabs were rolled and rubbed over the entire used surface of each shadow, and each inoculum was streaked onto the surfaces of blood agar plates. Of the 1,345 individual samples obtained, 67% were contaminated with one or more species of microorganisms representing the genera Staphylococcus, Micrococcus, Corynebacterium, Acinetobacter, Bacillus, and Moraxella. We also purchased two different brands of water-miscible eye shadows in replicate unit containers. Each brand was challenged separately with a few hundred to several thousand colony-forming units of Staphylococcus aureus, Pseudomonas aeruginosa, or Acinetobacter calcoaceticus. Both brands permitted growth of P. aeruginosa but not growth of S. aureus. A. calcoaceticus was inhibited after inoculation into one brand. With the other brand, the inoculum of Acinetobacter multiplied in one of the two different lots tested. This experimental challenge procedure can serve as a useful model system for studying the behavior of microbes in eye shadows and similar matrices. PMID:7283427

  18. Influence of Earth's shadowing effects on space debris stability

    NASA Astrophysics Data System (ADS)

    Hubaux, Ch.; Libert, A.-S.; Delsate, N.; Carletti, T.

    2013-01-01

    Solar radiation pressure affects the evolution of high area-to-mass geostationary space debris. In this work, we extend the stability study of Valk et al. (2009) by considering the influence of Earth's shadows on the short- and long-term time evolutions of space debris. To assess the orbits stability, we use the Mean Exponential Growth factor of Nearby Orbits (MEGNO), which is an efficient numerical tool to distinguish between regular and chaotic behaviors. To reliably compute long-term space debris motion, we resort to the Global Symplectic Integrator (GSI) of Libert et al. (2011) which consists in the symplectic integration of both Hamiltonian equations of motion and variational equations. We show how to efficiently compute the MEGNO indicator in a complete symplectic framework, and we also discuss the choice of a symplectic integrator, since propagators adapted to the structure of the Hamiltonian equations of motion are not necessarily suited for the associated variational equations. The performances of our method are illustrated and validated through the study of the Arnold diffusion problem. We then analyze the effects of Earth's shadows, using the adapted conical and cylindrical Earth's shadowing models introduced by Hubaux et al. (2012) as the smooth shadow function deriving from these models can be easily included into the variational equations. Our stability study shows that Earth's shadows greatly affect the global behaviour of space debris orbits by increasing the size of chaotic regions around the geostationary altitude. We also emphasize the differences in the results given by conical or cylindrical Earth's shadowing models. Finally, such results are compared with a non-symplectic integration scheme.

  19. Binary black hole shadows, chaotic scattering and the Cantor set

    NASA Astrophysics Data System (ADS)

    Shipley, Jake O.; Dolan, Sam R.

    2016-09-01

    We investigate the qualitative features of binary black hole shadows using the model of two extremally charged black holes in static equilibrium (a Majumdar–Papapetrou solution). Our perspective is that binary spacetimes are natural exemplars of chaotic scattering, because they admit more than one fundamental null orbit, and thus an uncountably infinite set of perpetual null orbits which generate scattering singularities in initial data. Inspired by the three-disc model, we develop an appropriate symbolic dynamics to describe planar null geodesics on the double black hole spacetime. We show that a one-dimensional (1D) black hole shadow may be constructed through an iterative procedure akin to the construction of the Cantor set; thus the 1D shadow is self-similar. Next, we study non-planar rays, to understand how angular momentum affects the existence and properties of the fundamental null orbits. Taking slices through 2D shadows, we observe three types of 1D shadow: regular, Cantor-like, and highly chaotic. The switch from Cantor-like to regular occurs where outer fundamental orbits are forbidden by angular momentum. The highly chaotic part is associated with an unexpected feature: stable and bounded null orbits, which exist around two black holes of equal mass M separated by {a}1\\lt a\\lt \\sqrt{2}{a}1, where {a}1=4M/\\sqrt{27}. To show how this possibility arises, we define a certain potential function and classify its stationary points. We conjecture that the highly chaotic parts of the 2D shadow possess the Wada property. Finally, we consider the possibility of following null geodesics through event horizons, and chaos in the maximally extended spacetime.

  20. Quasi-static displacement calibration system for a “Violin-Mode” shadow-sensor intended for Gravitational Wave detector suspensions

    SciTech Connect

    Lockerbie, N. A.; Tokmakov, K. V.

    2014-10-15

    This paper describes the design of, and results from, a calibration system for optical linear displacement (shadow) sensors. The shadow sensors were designed to detect “Violin-Mode” (VM) resonances in the 0.4 mm diameter silica fibre suspensions of the test masses/mirrors of Advanced Laser Interferometer Gravitational Wave Observatory gravitational wave interferometers. Each sensor illuminated the fibre under test, so as to cast its narrow shadow onto a “synthesized split photodiode” detector, the shadow falling over adjacent edges of the paired photodiodes. The apparatus described here translated a vertically orientated silica test fibre horizontally through a collimated Near InfraRed illuminating beam, whilst simultaneously capturing the separate DC “shadow notch” outputs from each of the paired split photodiode detectors. As the ratio of AC to DC photocurrent sensitivities to displacement was known, a calibration of the DC response to quasi-static shadow displacement allowed the required AC sensitivity to vibrational displacement to be found. Special techniques are described for generating the required constant scan rate for the test fibre using a DC motor-driven stage, for removing “jitter” at such low translation rates from a linear magnetic encoder, and so for capturing the two shadow-notch signals at each micrometre of the test fibre's travel. Calibration, across the four detectors of this work, gave a vibrational responsivity in voltage terms of (9.45 ± 1.20) MV (rms)/m, yielding a VM displacement sensitivity of (69 ± 13) pm (rms)/√Hz, at 500 Hz, over the required measuring span of ±0.1 mm.

  1. Proton shadow camera using CR-39 track detectors

    SciTech Connect

    Stone, G.F.; Ceglio, N.M.

    1983-09-01

    We have developed a capability for imaging proton sources of moderate energy (6 MeV), with moderate spatial resolution (approx. = 9 ..mu..m), as a diagnostic for laser fusion research. Our technique involves the use of Fresnel zone plate coded imaging coupled with nuclear track detectors (CR-39). We report on a series of test experiments in which a zone plate shadow camera successfully produced images of a proton source distribution. The zone plate shadow patterns were optically reconstructed in higher order producing diffraction-limited point response images with FWHM values of approx. = 9 ..mu..m for a 6 MeV proton source.

  2. Plant, soil, and shadow reflectance components of row crops

    NASA Technical Reports Server (NTRS)

    Richardson, A. J.; Wiegand, C. L.; Gausman, H. W.; Cuellar, J. A.; Gerbermann, A. H.

    1975-01-01

    Data from the first Earth Resource Technology Satellite (LANDSAT-1) multispectral scanner (MSS) were used to develop three plant canopy models (Kubelka-Munk (K-M), regression, and combined K-M and regression models) for extracting plant, soil, and shadow reflectance components of cropped fields. The combined model gave the best correlation between MSS data and ground truth, by accounting for essentially all of the reflectance of plants, soil, and shadow between crop rows. The principles presented can be used to better forecast crop yield and to estimate acreage.

  3. Points of View: Shadows, Photons, Planets, and Life

    NASA Astrophysics Data System (ADS)

    Sullivan, Woodruff T., III

    2005-01-01

    I combine here a potpourri of topics that have been of keen interest over my career. The first is gnomonics, the art and science of sundials: at its heart are the shadows that elegantly chart the motions of the Sun on a defined surface. More broadly, shadows have been amazingly productive in astronomy through the centuries. Examples range from the ancient Greeks (the distances of Moon and Sun) to the Scientific Revolution (Roemer's determination of the speed of light). They also include twentieth century science (solar eclipse observations relative to general relativity) and current twenty-first century research (transits of extrasolar planets).

  4. Shadowing: Who Benefits and How? Uncovering a Booming EFL Teaching Technique for Listening Comprehension

    ERIC Educational Resources Information Center

    Hamada, Yo

    2016-01-01

    This study examines common claims associated with shadowing. Studies in Japan conclude that shadowing is effective for improving learners' listening skills. Two common claims are that shadowing is effective for lower-proficiency learners and that it enhances learners' phoneme perception, thus improving listening comprehension skills. The former…

  5. Determining an East-West Line with the Shadow of the Sun

    ERIC Educational Resources Information Center

    Sorenson, Charles W.

    1972-01-01

    Describes the method for verifying the accuracy of the shadow-stick method of determining east-west line with the shadow of sun. Description is also included for determining South by using a watch-shadow method. (Author/PS)

  6. Dismantling the Imperialist Discourse Shadowing Mexican Immigrant Children

    ERIC Educational Resources Information Center

    Miller, Lisa L.

    2006-01-01

    This article unravels the political, public, and private discourse shadowing Mexican immigrants in the Southwestern U.S. The author illustrates how the dominant discourse with regard to immigration in the U.S. has led to the dehumanization of migrant people significantly impacting what occurs in their daily lives and directly influencing the…

  7. Unusual shadowing effects in particle production off nuclei

    NASA Astrophysics Data System (ADS)

    Blankenbecler, R.; Capella, A.; Van, J. Tran Thanh; Pajares, C.; Ramallo, A. V.

    1981-12-01

    Some consequences of the AKG cutting rules for particle production off nuclei at low transverse momentum are examined. The condition for an arbitrarily defined cross section to be shadowed only by itself is given. Some physical examples and experimental consequences are discussed. Many new tests of certain general features of reggeon field theory follow from our results.

  8. Spiral Waves Triggered by Shadows in Transition Disks

    NASA Astrophysics Data System (ADS)

    Montesinos, Matías; Perez, Sebastian; Casassus, Simon; Marino, Sebastian; Cuadra, Jorge; Christiaens, Valentin

    2016-05-01

    Circumstellar asymmetries such as central warps have recently been shown to cast shadows on outer disks. We investigate the hydrodynamical consequences of such variable illumination on the outer regions of a transition disk, and the development of spiral arms. Using 2D simulations, we follow the evolution of a gaseous disk passively heated by the central star, under the periodic forcing of shadows with an opening angle of ∼28°. With a lower pressure under the shadows, each crossing results in a variable azimuthal acceleration, which in time develops into spiral density waves. Their pitch angles evolve from Π ∼ 15°–22° at the onset, to ∼11°–14°, over ∼65 au to 150 au. Self-gravity enhances the density contrast of the spiral waves, as also reported previously for spirals launched by planets. Our control simulations with unshadowed irradiation do not develop structures, except for a different form of spiral waves seen at later times only in the gravitationally unstable control case. Scattered light predictions in the H-band show that such illumination spirals should be observable. We suggest that spiral arms in the case-study transition disk HD 142527 could be explained as a result of shadowing from the tilted inner disk.

  9. S-factor in the framework of the ``shadow`` model

    SciTech Connect

    Scalia, A. |

    1995-02-05

    The {ital S}({ital E}) factor is obtained in the framework of the ``shadow`` model. The analytical expression of the {ital S}({ital E}) function is not compatible with a {ital S}-factor which is a slow varying function of the energy. {copyright} {ital 1995} {ital American} {ital Institute} {ital of} {ital Physics}.

  10. Constraining Item Exposure in Computerized Adaptive Testing with Shadow Tests

    ERIC Educational Resources Information Center

    van der Linden, Wim J.; Veldkamp, Bernard P.

    2004-01-01

    Item-exposure control in computerized adaptive testing is implemented by imposing item-ineligibility constraints on the assembly process of the shadow tests. The method resembles Sympson and Hetter's (1985) method of item-exposure control in that the decisions to impose the constraints are probabilistic. The method does not, however, require…

  11. Conspicuous Invisibility: Shadowing as a Data Collection Strategy

    ERIC Educational Resources Information Center

    Quinlan, Elizabeth

    2008-01-01

    Shadowing entails a researcher closely following a subject over a period of time to investigate what people actually do in the course of their everyday lives, not what their roles dictate of them. Behaviors, opinions, actions, and explanations for those actions are reflected in the resulting thick, descriptive data. There is little written that…

  12. Shadow Formation at Preschool from a Socio-materiality Perspective

    NASA Astrophysics Data System (ADS)

    Impedovo, Maria Antonietta; Delserieys-Pedregosa, Alice; Jégou, Corinne; Ravanis, Konstantinos

    2016-05-01

    The paper is set in socio-material farming to offer a way of conceptualising actions and interactions of children in preschool involved in the understanding of scientific concepts. A model of early science education about the physical phenomena of shadow formation is implemented in group work in a French context. The research involved 44 children (13 females and 31 males) of 5-6 years old. The research design was organised in three video recording steps: pre-test, teaching session and post-test. We focus on the analysis of nine teaching sessions to investigate children's `understanding' of shadow formation. A descriptive and qualitative approach was used. In particular, we have identified three main categories (the interaction of the children with the tools, the embodiment and verbal dimension)—with respective indicators—to perform the analysis. From the results, all the categories explored seem to influence each other: all material, human and social dimensions contribute to the children's understanding of shadow formation. Also we have identified some elements that can serve as a potential source of improvement of the teaching session on shadow formation. Finally, the research provides insights on how to improve science activities in preschool with the aim of supporting early understanding of physical phenomena.

  13. Shadow Education: Theory, Analysis and Future Directions--A Rejoinder

    ERIC Educational Resources Information Center

    Buchmann, Claudia; Condron, Dennis J.; Roscigno, Vincent J.

    2010-01-01

    The authors welcome and appreciate the comments of Eric Grodsky and Sigal Alon on their article "Shadow Education, American Style: Test Preparation, the SAT and College Enrollment." In their comments, Grodsky takes issue with several important theoretical and methodological aspects of their article and Alon highlights key processes pertaining to…

  14. 1. OBLIQUE VIEW OF THE NORTH SIDE (IN SHADOW) AND ...

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

    1. OBLIQUE VIEW OF THE NORTH SIDE (IN SHADOW) AND THE NORTH PART OF THE WEST SIDE, FROM A BOOM LIFT NEAR THE NORTHWEST CORNER. BUILDING NO. 21 (OFFICE/FIREHOUSE) IS THE FIRST SMALL BUILDING AT THE FAR LEFT. - United Engineering Company Shipyard, Inspection & Repair Shops, 2900 Main Street, Alameda, Alameda County, CA

  15. Spiral Waves Triggered by Shadows in Transition Disks

    NASA Astrophysics Data System (ADS)

    Montesinos, Matías; Perez, Sebastian; Casassus, Simon; Marino, Sebastian; Cuadra, Jorge; Christiaens, Valentin

    2016-05-01

    Circumstellar asymmetries such as central warps have recently been shown to cast shadows on outer disks. We investigate the hydrodynamical consequences of such variable illumination on the outer regions of a transition disk, and the development of spiral arms. Using 2D simulations, we follow the evolution of a gaseous disk passively heated by the central star, under the periodic forcing of shadows with an opening angle of ˜28°. With a lower pressure under the shadows, each crossing results in a variable azimuthal acceleration, which in time develops into spiral density waves. Their pitch angles evolve from Π ˜ 15°–22° at the onset, to ˜11°–14°, over ˜65 au to 150 au. Self-gravity enhances the density contrast of the spiral waves, as also reported previously for spirals launched by planets. Our control simulations with unshadowed irradiation do not develop structures, except for a different form of spiral waves seen at later times only in the gravitationally unstable control case. Scattered light predictions in the H-band show that such illumination spirals should be observable. We suggest that spiral arms in the case-study transition disk HD 142527 could be explained as a result of shadowing from the tilted inner disk.

  16. Raiders of the Lost Archetype: The Quest and the Shadow.

    ERIC Educational Resources Information Center

    Roth, Lane

    The film "Raiders of the Lost Ark," a timeless story about the heroic quest for a sacred object and the conflict between good and evil, employs cross-cultural, durable symbols to establish quickly a locus of motives with a large, differentiated movie audience. The archetypes of the quest and of shadow are at the core of this film; they create a…

  17. How To Have a Successful Groundhog Job Shadow Day.

    ERIC Educational Resources Information Center

    America's Promise: The Alliance for Youth, Alexandria, VA.

    This guide, created for Groundhog Job Shadow Day (GJSD), held on February 2, 1999, provides structured activities for both the classroom and the job site to help students understand the importance and the relevance of their education and see firsthand the range of knowledge, skills, and teamwork that the workplace demands. In addition, the…

  18. How To Have a Successful Groundhog Job Shadow Day.

    ERIC Educational Resources Information Center

    America's Promise: The Alliance for Youth, Alexandria, VA.

    This guide, which is an updated version of the guide created for the Groundhog Job Shadow Day (GJSD) that was held on February 2, 1999, provides structured activities that classroom teachers and job sites can use to help students understand the importance and relevance of their education and see firsthand the range of knowledge, skills, and…

  19. A note on the computation of antenna-blocking shadows

    NASA Technical Reports Server (NTRS)

    Levy, R.

    1993-01-01

    A simple and readily applied method is provided to compute the shadow on the main reflector of a Cassegrain antenna, when cast by the subreflector and the subreflector supports. The method entails some convenient minor approximations that will produce results similar to results obtained with a lengthier, mainframe computer program.

  20. The Groundhog Job Shadow Day Public Awareness Guide.

    ERIC Educational Resources Information Center

    Junior Achievement, Inc., Colorado Springs, CO.

    This guide was created to help community groups create publicity plans and follow through to promote public awareness of Groundhog Job Shadow Day (GJSD) on February 2, 1999. The guide promotes the goal of raising public awareness for the importance of business and education working together to provide hands-on career experiences for students. It…

  1. EUV telecentricity and shadowing errors impact on process margins

    NASA Astrophysics Data System (ADS)

    Civay, D.; Hosler, E.; Chauhan, V.; Guha Neogi, T.; Smith, L.; Pritchard, D.

    2015-03-01

    Monte Carlo simulations are used in the semiconductor industry to evaluate variability limits in design rule generation, commonly for interaction between different layers. The variability of the geometry analyzed is determined mainly by the lithography, process and OPC used. Monte Carlo methods for design rule evaluation can provide the requisite level of accuracy, and are suitable for two or more layer interactions because the variations on one can be assumed to be independent of variations on the other(s). The variability parameters and budget utilized in optical Monte Carlo simulations is well-established. With the upcoming implementation of EUV lithography the variability budget will be impacted. EUV has an off-axis illumination angle that complicates the lithography process by causing telecentricity and shadowing errors. Telecentricity errors manifest as a printed feature being shifted relative to the design. The amount the feature is shifted is a function of the pattern density and design. Shadowing is caused by the 3D nature of the mask combined with EUV reflective mask technology. A shadow occurs at feature edges, where the source does not fully illuminate. Telecentricity and shadowing errors, although small at the 10 nm node, will increase in relative size compared to the features printed beyond the 7 nm node. Telecentricity and shadowing errors are complex in nature and can't be compensated for with a flat bias. These errors unique to EUV are incorporated into Monte Carlo simulations and evaluated against the standard cell design layers. The effect of these variability parameters is evaluated on critical 7 nm node layout clips.

  2. Depth and Horizontal Distribution of Volatiles in Lunar Permanently Shadowed Regions

    NASA Astrophysics Data System (ADS)

    Hurley, D. M.; Bussey, B.; Lawrence, D. J.; Gladstone, R.; Elphic, R. C.; Vondrak, R. R.

    2011-12-01

    Neutron spectroscopy from Lunar Prospector returned data consistent with the presence of water ice in the near-subsurface of the Moon in permanently shadowed regions (PSRs) at low spatial resolution. Clementine and ground-based radar returned tantalizing, but inconclusive evidence of ice in lunar PSRs. Later, Mini-RF on Chandrayaan-1 and LRO detected a signature consistent with water ice in some polar craters on the Moon, but not all PSRs. Similarly, LEND on LRO detected a heterogeneous distribution of hydrogen among lunar PSRs. In addition, LAMP on LRO detected FUV spectra consistent with a heterogeneous distribution of frost on the surface of permanently shadowed regions. Yet the weakest spectral feature from LAMP was associated with the crater with the strongest hydrogen feature from LEND. The impact of LCROSS into Cabeus released water and other volatiles, but abundances were higher than the background amounts detected by neutron spectroscopy implying heterogeneity within that PSR. Data from any one instrument taken alone would lead one to a different conclusion about the distribution of volatiles than data taken from any other single instrument. Although the data from different instrumentation can seem to be disparate, the apparent discrepancy results from the different fields of view and sensitivities of the detection techniques. The complementary nature of these data can be exploited to provide a multi-dimensional view of volatiles in lunar PSRs. We apply a Monte Carlo model to describe the retention and redistribution of volatiles within lunar cold traps. The model runs constrain the coherence of volatile deposits with depth, area, and time, which allows us to examine how a given volatile distribution would appear to remote sensing experiments. This provides a big picture framework for integrating the observations of volatiles on the surface and at depth at the poles of the Moon with the goal of finding a distribution of volatiles in lunar PSRs consistent

  3. Galileo in-situ dust measurements and the significance of planetary shadowing in shaping Jupiter's gossamer ring structure

    NASA Astrophysics Data System (ADS)

    Krueger, Harald; Hamilton, Douglas P.; Moissl, Richard; Gruen, Eberhard

    particle ring material interior to Thebe's orbit. The existence of this partially evacuated gap in ring is also indirectly confirmed by Galileo in-situ energetic particle measurements (Norbert Krupp, priv. comm.). Recent modelling (Hamilton & Kr¨ger, u Nature, submitted) shows that time variable electromagnetic effects can account for all of these surprising results. In particular, when the ring particles travel through Jupiter's shadow, dust grain electric charges vary systematically, driving grains out into the Thebe Extension and matching the Galileo in-situ dust measurements.

  4. FACET: a radiation view factor computer code for axisymmetric, 2D planar, and 3D geometries with shadowing

    SciTech Connect

    Shapiro, A.B.

    1983-08-01

    The computer code FACET calculates the radiation geometric view factor (alternatively called shape factor, angle factor, or configuration factor) between surfaces for axisymmetric, two-dimensional planar and three-dimensional geometries with interposed third surface obstructions. FACET was developed to calculate view factors for input to finite-element heat-transfer analysis codes. The first section of this report is a brief review of previous radiation-view-factor computer codes. The second section presents the defining integral equation for the geometric view factor between two surfaces and the assumptions made in its derivation. Also in this section are the numerical algorithms used to integrate this equation for the various geometries. The third section presents the algorithms used to detect self-shadowing and third-surface shadowing between the two surfaces for which a view factor is being calculated. The fourth section provides a user's input guide followed by several example problems.

  5. The Formation of Shadows: The Case of the Position of a Light Source in Relevance to the Shadow

    ERIC Educational Resources Information Center

    Ravanis, Konstantinos; Zacharos, Konstantinos; Vellopoulou, Angeliki

    2010-01-01

    The study of pupils' representations of physics concepts and phenomena constitutes a central part of Science Education research, as they play a decisive role in teaching. In the study presented here, we investigate 212 fifth grade pupils' mental representations of the formation of shadows, before they were taught about it in school. The empirical…

  6. In the Shadow/from the Shadow: The Principal as a Reflective Practitioner in Trinidad and Tobago

    ERIC Educational Resources Information Center

    Bristol, Laurette; Esnard, Talia; Brown, Launcelot

    2015-01-01

    This case highlights a school principal's leading practice as she worked to transform the social and educational status of students, teachers, and community in a small urban primary school. We employ shadowing, a technique popularized in work-based education and photography, as reflective and research tools. Teaching notes provide insight into the…

  7. LDRD final report on enhanced edge detection techniques for manufacturing quality control and materials characterization

    SciTech Connect

    Osbourn, G.C.

    1997-01-01

    Detecting object boundaries in the presence of cast shadows is a difficult task for machine vision systems. A new edge detector is presented which responds to shadow penumbras and abrupt object edges with distinguishable signals. The detector requires the use of spatially extended light sources and sufficient video resolution to resolve the shadow penumbras of interest. Detection of high frequency noise is suppressed without requiring image-dependent adjustment of signal thresholds. The ability of the edge operator to distinguish shadow penumbras from abrupt object boundaries while suppressing responses to high frequency noise and texture is illustrated with idealized shadow and object edge intensity profiles. Selective detection of object boundaries in a video scene with a cast shadow has also been demonstrated with this operator.

  8. Usability of multiangular imaging spectroscopy data for analysis of vegetation canopy shadow fraction in boreal forest

    NASA Astrophysics Data System (ADS)

    Markiet, Vincent; Perheentupa, Viljami; Mõttus, Matti; Hernández-Clemente, Rocío

    2016-04-01

    Imaging spectroscopy is a remote sensing technology which records continuous spectral data at a very high (better than 10 nm) resolution. Such spectral images can be used to monitor, for example, the photosynthetic activity of vegetation. Photosynthetic activity is dependent on varying light conditions and varies within the canopy. To measure this variation we need very high spatial resolution data with resolution better than the dominating canopy element size (e.g., tree crown in a forest canopy). This is useful, e.g., for detecting photosynthetic downregulation and thus plant stress. Canopy illumination conditions are often quantified using the shadow fraction: the fraction of visible foliage which is not sunlit. Shadow fraction is known to depend on view angle (e.g., hot spot images have very low shadow fraction). Hence, multiple observation angles potentially increase the range of shadow fraction in the imagery in high spatial resolution imaging spectroscopy data. To investigate the potential of multi-angle imaging spectroscopy in investigating canopy processes which vary with shadow fraction, we obtained a unique multiangular airborne imaging spectroscopy data for the Hyytiälä forest research station located in Finland (61° 50'N, 24° 17'E) in July 2015. The main tree species are Norway spruce (Picea abies L. karst), Scots pine (Pinus sylvestris L.) and birch (Betula pubescens Ehrh., Betula pendula Roth). We used an airborne hyperspectral sensor AISA Eagle II (Specim - Spectral Imaging Ltd., Finland) mounted on a tilting platform. The tilting platform allowed us to measure at nadir and approximately 35 degrees off-nadir. The hyperspectral sensor has a 37.5 degrees field of view (FOV), 0.6m pixel size, 128 spectral bands with an average spectral bandwidth of 4.6nm and is sensitive in the 400-1000 nm spectral region. The airborne data was radiometrically, atmospherically and geometrically processed using the Parge and Atcor software (Re Se applications Schl

  9. Incorporation of thermal shadows into real-time infrared three-dimensional image generation

    NASA Astrophysics Data System (ADS)

    Klein, Andreas; Nischwitz, Alfred; Schätz, Peter; Obermeier, Paul

    2014-05-01

    In the infrared spectrum, two contributions to shadows exist: one part is reflective shadows resulting from occlusion of instantly reflected infrared rays, and the other part is thermal (IR) shadows occurring through occlusion of irradiance in the past. The realization of thermal shadows requires a thermal balance calculation in four-dimensions (three-dimensional geometry in one-dimensional time), which is computationally expensive, and therefore mostly used for nonreal-time simulations. We present an approximation of thermal shadows resulting from the occlusion of direct rays from IR emitters. Our approach uses programmable graphics cards to achieve real-time frame rates in scenes with dynamic geometry.

  10. Nanostructured biosensing platform-shadow edge lithography for high-throughput nanofabrication.

    PubMed

    Bai, John G; Yeo, Woon-Hong; Chung, Jae-Hyun

    2009-02-01

    One of the critical challenges in nanostructured biosensors is to manufacture an addressable array of nanopatterns at low cost. The addressable array (1) provides multiplexing for biomolecule detection and (2) enables direct detection of biomolecules without labeling and amplification. To fabricate such an array of nanostructures, current nanolithography methods are limited by the lack of either high throughput or high resolution. This paper presents a high-resolution and high-throughput nanolithography method using the compensated shadow effect in high-vacuum evaporation. The approach enables the fabrication of uniform nanogaps down to 20 nm in width across a 100 mm silicon wafer. The nanogap pattern is used as a template for the routine fabrication of zero-, one-, and two-dimensional nanostructures with a high yield. The method can facilitate the fabrication of nanostructured biosensors on a wafer scale at a low manufacturing cost. PMID:19156295

  11. Shadowing Observations of the Soft X-ray Background with XMM-Newton and Suzaku

    NASA Astrophysics Data System (ADS)

    Henley, David; Shelton, Robin L.; Cumbee, Renata; Stancil, Phillip C.

    2014-08-01

    Shadows in the soft X-ray background allow one to separate the Galactic halo's X-ray emission from the local foreground emission due to the Local Bubble and/or solar wind charge exchange. Accurate measurements of the foreground emission and of the halo emission are needed to test models of solar wind charge exchange and of the origin of the hot halo gas, respectively.We present results from XMM-Newton and Suzaku observations of six shadowing interstellar clouds. While results for some of these shadows have previously been published, this is the first uniform analysis of a sample of CCD-resolution shadowing observations. Our sample includes two shadows in the northern Galactic hemisphere, for which there are no published CCD-resolution shadowing observations, and a compact shadowing cloud that fits into a single XMM-Newton field.For each shadow, we fit spectral models to the on- and off-shadow spectra in order to separate the Galactic halo emission from the foreground emission. For this purpose, we explore different foreground spectral models, including a thermal plasma (Local Bubble) model, and solar wind charge exchange models. We can therefore examine the sensitivity of the inferred halo parameters to the assumed foreground model. In addition, two of our shadows have been observed with both XMM-Newton and Suzaku - we can use these shadows to test whether or not a given foreground model yields consistent halo measurements from two observations separated in time.

  12. Helium beam shadowing for high spatial resolution patterning of antibodies on microstructured diagnostic surfaces

    PubMed Central

    Cacao, Eliedonna; Sherlock, Tim; Nasrullah, Azeem; Kemper, Steven; Knoop, Jennifer; Kourentzi, Katerina; Ruchhoeft, Paul; Stein, Gila E; Atmar, Robert L; Willson, Richard C

    2013-01-01

    Abstract We have developed a technique for the high-resolution, self-aligning, and high-throughput patterning of antibody binding functionality on surfaces by selectively changing the reactivity of protein-coated surfaces in specific regions of a workpiece with a beam of energetic helium particles. The exposed areas are passivated with bovine serum albumin (BSA) and no longer bind the antigen. We demonstrate that patterns can be formed (1) by using a stencil mask with etched openings that forms a patterned exposure, or (2) by using angled exposure to cast shadows of existing raised microstructures on the surface to form self-aligned patterns. We demonstrate the efficacy of this process through the patterning of anti-lysozyme, anti-Norwalk virus, and anti-Escherichia coli antibodies and the subsequent detection of each of their targets by the enzyme-mediated formation of colored or silver deposits, and also by binding of gold nanoparticles. The process allows for the patterning of three-dimensional structures by inclining the sample relative to the beam so that the shadowed regions remain unaltered. We demonstrate that the resolution of the patterning process is of the order of hundreds of nanometers, and that the approach is well-suited for high throughput patterning. PMID:24706125

  13. Helium beam shadowing for high spatial resolution patterning of antibodies on microstructured diagnostic surfaces.

    PubMed

    Cacao, Eliedonna; Sherlock, Tim; Nasrullah, Azeem; Kemper, Steven; Knoop, Jennifer; Kourentzi, Katerina; Ruchhoeft, Paul; Stein, Gila E; Atmar, Robert L; Willson, Richard C

    2013-12-01

    We have developed a technique for the high-resolution, self-aligning, and high-throughput patterning of antibody binding functionality on surfaces by selectively changing the reactivity of protein-coated surfaces in specific regions of a workpiece with a beam of energetic helium particles. The exposed areas are passivated with bovine serum albumin (BSA) and no longer bind the antigen. We demonstrate that patterns can be formed (1) by using a stencil mask with etched openings that forms a patterned exposure, or (2) by using angled exposure to cast shadows of existing raised microstructures on the surface to form self-aligned patterns. We demonstrate the efficacy of this process through the patterning of anti-lysozyme, anti-Norwalk virus, and anti-Escherichia coli antibodies and the subsequent detection of each of their targets by the enzyme-mediated formation of colored or silver deposits, and also by binding of gold nanoparticles. The process allows for the patterning of three-dimensional structures by inclining the sample relative to the beam so that the shadowed regions remain unaltered. We demonstrate that the resolution of the patterning process is of the order of hundreds of nanometers, and that the approach is well-suited for high throughput patterning. PMID:24706125

  14. Searching for a shadow biosphere on Earth as a test of the 'cosmic imperative'.

    PubMed

    Davies, P C W

    2011-02-13

    Estimates for the number of communicating civilizations in the galaxy, based on the so-called Drake equation, are meaningless without a plausible estimate for the probability that life will emerge on an Earth-like planet. In the absence of a theory of the origin of life, that number can be anywhere from 0 to 1. Distinguished scientists have been known to argue that life on Earth is a freak accident, unique in the observable universe and, conversely, that life is almost bound to arise in the course of time, given Earth-like conditions. De Duve, adopting the latter position, coined the phrase that 'life is a cosmic imperative'. De Duve's position would be immediately verified if we were to discover a second sample of life that we could be sure arose from scratch independently of known life. Given the current absence of evidence for life beyond Earth, the best way to test the hypothesis of the cosmic imperative is to see whether terrestrial life began more than once. If it did, it is possible that descendants of a second genesis might be extant, forming a sort of 'shadow biosphere' existing alongside, or perhaps interpenetrating, the known biosphere. I outline a strategy to detect the existence of such a shadow biosphere. PMID:21220286

  15. Pedestrian detection by multispectral fusion

    NASA Astrophysics Data System (ADS)

    Ma, Yunqian; Wang, Zheng; Bazakos, Mike

    2006-04-01

    Security systems increasingly rely on the use of Automated Video Surveillance (AVS) technology. In particular the use of digital video renders itself to internet and local communications, remote monitoring, and to computer processing. AVS systems can perform many tedious and repetitive tasks currently performed by trained security personnel. AVS technology has already made some significant steps towards automating some basic security functions such as: motion detection, object tracking and event-based video recording. However, there are still many problems associated with just these automated functions, which need to be addressed further. Some examples of these problems are: the high "false alarm rate" and the "loss of track" under total or partial occlusion, when used under a wide range of operational parameters (day, night, sunshine, cloudy, foggy, range, viewing angle, clutter, etc.). Current surveillance systems work well only under a narrow range of operational parameters. Therefore, they need be hardened against a wide range of operational conditions. In this paper, we present a Multi-spectral fusion approach to perform accurate pedestrian segmentation under varying operational parameters. Our fusion method combines the "best" detection results from the visible images and the "best" from the thermal images. Commonly, the motion detection results in the visible images are easily affected by noise and shadows. The objects in the thermal image are relatively stable, but they may be missing some parts of the objects, because they thermally blend with the background. Our method makes use of the "best" object components and de-emphasize the "not best".

  16. X-RAY SHADOWING EXPERIMENTS TOWARD INFRARED DARK CLOUDS

    SciTech Connect

    Anderson, L. D.; Bania, T. M.; Snowden, S. L.

    2010-10-01

    We searched for X-ray shadowing toward two infrared dark clouds (IRDCs) using the MOS detectors on XMM-Newton to learn about the Galactic distribution of X-ray emitting plasma. IRDCs make ideal X-ray shadowing targets of 3/4 keV photons due to their high column densities, relatively large angular sizes, and known kinematic distances. Here we focus on two clouds near 30{sup 0} Galactic longitude at distances of 2 and 5 kpc from the Sun. We derive the foreground and background column densities of molecular and atomic gas in the direction of the clouds. We find that the 3/4 keV emission must be distributed throughout the Galactic disk. It is therefore linked to the structure of the cooler material of the interstellar medium and to the birth of stars.

  17. The permanently shadowed regions of dwarf planet Ceres

    NASA Astrophysics Data System (ADS)

    Schorghofer, Norbert; Mazarico, Erwan; Platz, Thomas; Preusker, Frank; Schröder, Stefan E.; Raymond, Carol A.; Russell, Christopher T.

    2016-07-01

    Ceres has only a small spin axis tilt (4°), and craters near its rotational poles can experience permanent shadow and trap volatiles, as is the case on Mercury and on Earth's Moon. Topography derived from stereo imaging by the Dawn spacecraft is used to calculate direct solar irradiance that defines the extent of the permanently shadowed regions (PSRs). In the northern polar region, PSRs cover ˜1800 km2 or 0.13% of the hemisphere, and most of the PSRs are cold enough to trap water ice over geological time periods. Based on modeling of the water exosphere, water molecules seasonally reside around the winter pole and ultimately an estimated 0.14% of molecules get trapped. Even for the lowest estimates of the amount of available water, this predicts accumulation rates in excess of loss rates, and hence, there should be fresh ice deposits in the cold traps.

  18. The Permanently Shadowed Regions of Dwarf Planet Ceres

    NASA Technical Reports Server (NTRS)

    Schorghofer, Norbert; Mazarico, Erwan; Platz, Thomas; Preusker, Frank; Schroeder, Stefan E.; Raymond, Carol A.; Russell, Christopher T.

    2016-01-01

    Ceres has only a small spin axis tilt (4 deg), and craters near its rotational poles can experience permanent shadow and trap volatiles, as is the case on Mercury and on Earth's Moon. Topography derived from stereo imaging by the Dawn spacecraft is used to calculate direct solar irradiance that defines the extent of the permanently shadowed regions (PSRs). In the northern polar region, PSRs cover approximately 1800 sq km or 0.13% of the hemisphere, and most of the PSRs are cold enough to trap water ice over geological time periods. Based on modeling of the water exosphere, water molecules seasonally reside around the winter pole and ultimately an estimated 0.14% of molecules get trapped. Even for the lowest estimates of the amount of available water, this predicts accumulation rates in excess of loss rates, and hence, there should be fresh ice deposits in the cold traps.

  19. X-Ray Shadowing Experiments Toward Infrared Dark Clouds

    NASA Technical Reports Server (NTRS)

    Anderson, L. E.; Snowden, S.; Bania, T. M.

    2009-01-01

    We searched for X-ray shadowing toward two infrared dark clouds (IRDCs) using the MOS detectors on XMM-Newton to learn about the Galactic distribution of X-ray emitting plasma. IRDCs make ideal X-ray shadowing targets of 3/4 keY photons due to their high column densities, relatively large angular sizes, and known kinematic distances. Here we focus on two clouds near 30 deg Galactic longitude at distances of 2 and 5 kpc from the Sun. We derive the foreground and background column densities of molecular and atomic gas in the direction of the clouds. We find that the 3/4 ke V emission must be distributed throughout the Galactic disk. It is therefore linked to the structure of the cooler material of the ISM, and to the birth of stars.

  20. THERMAL SHADOWS AND COMPOSITIONAL STRUCTURE IN COMET NUCLEI

    SciTech Connect

    Guilbert-Lepoutre, Aurelie; Jewitt, David E-mail: jewitt@ucla.edu

    2011-12-10

    We use a fully three-dimensional thermal evolution model to examine the effects of a non-uniform surface albedo on the subsurface thermal structure of comets. Surface albedo markings cast 'thermal shadows' with strong lateral thermal gradients. Corresponding compositional gradients can be strong, especially if the crystallization of amorphous water ice is triggered in the hottest regions. We show that the spatial extent of the structure depends mainly on the obliquity, thermal conductivity, and heliocentric distance. In some circumstances, subsurface structure caused by the thermal shadows of surface features can be maintained for more than 10 Myr, the median transport time from the Kuiper Belt to the inner solar system. Non-uniform compositional structure can be an evolutionary product and does not necessarily imply that comets consist of building blocks accumulated in different regions of the protoplanetary disk.

  1. Bow and stern waves triggered by the Moon's shadow boat

    NASA Astrophysics Data System (ADS)

    Liu, J. Y.; Sun, Y. Y.; Kakinami, Y.; Chen, C. H.; Lin, C. H.; Tsai, H. F.

    2011-09-01

    It has been predicted that the Moon's shadow, the cooling region, sweeping over the Earth's atmosphere with a supersonic speed could trigger bow waves since 1970. The longest total solar eclipse within next hundred years occurring on 22 July 2009 sweeps over the Eastern Asia region during the noontime period. An analysis of the Hilbert-Huang transform (HHT) is applied to study ionospheric TEC (total electron content) derived from ground-based GPS receivers in Taiwan and Japan. We not only find the feature of the predicted bow wave but also the stern wave on the equator side of the eclipse path, as well as the stern wake right behind the Moon's shadow boat. The bow and stern waves are formed by acoustic gravity waves of periods about 3 and/or 5 minutes traveling equatorward with a phase speed of about 100 m/s in the ionosphere.

  2. Extended Empirical Roadside Shadowing model from ACTS mobile measurements

    NASA Technical Reports Server (NTRS)

    Goldhirsh, Julius; Vogel, Wolfhard

    1995-01-01

    Employing multiple data bases derived from land-mobile satellite measurements using the Advanced Communications Technology Satellite (ACTS) at 20 GHz, MARECS B-2 at 1.5 GHz, and helicopter measurements at 870 MHz and 1.5 GHz, the Empirical Road Side Shadowing Model (ERS) has been extended. The new model (Extended Empirical Roadside Shadowing Model, EERS) may now be employed at frequencies from UHF to 20 GHz, at elevation angles from 7 to 60 deg and at percentages from 1 to 80 percent (0 dB fade). The EERS distributions are validated against measured ones and fade deviations associated with the model are assessed. A model is also presented for estimating the effects of foliage (or non-foliage) on 20 GHz distributions, given distributions from deciduous trees devoid of leaves (or in full foliage).

  3. Agitating mass transfer with a warped disc's shadow

    NASA Astrophysics Data System (ADS)

    Cambier, H.

    2015-10-01

    For compact objects fed by Roche lobe overflow, accretion-generated X-rays irradiating the donor star can alter gas flow towards the Lagrange point thus varying mass transfer. The latest work specific to this topic consists of simple yet insightful two-dimensional hydrodynamics simulations stressing the role of global flow. To explore how a time-varying disc shadow affects mass transfer, I generalize the geometry, employ a robust hydrodynamics solver, and use phase space analysis near the nozzle to include coriolis lift there. Without even exposing the nozzle, a warped disc's shadow can drive mass transfer cycles by shifting the equatorial edges of the irradiation patches in turns: drawing in denser ambient gas before sweeping it into the nozzle. Other important effects remain missing in two-dimensional models, which I discuss along with prospects for more detailed yet efficient models.

  4. Performance of RS codes in lognormally shadowed Rician channels

    NASA Astrophysics Data System (ADS)

    Trabelsi, Chokri; Yongacoglu, Abbas

    The performance of Reed-Solomon (RS) codes with binary phase shift keying transmission is determined for a class of fading models for land mobile satellite communications. The fading model has the structure of a Rician model except that the line-of-sight component is subjected to a lognormal transformation. By exploiting the statistical characteristics of the multipath fading and shadowing, an effective coding/interleaving scheme is proposed.

  5. Photon regions and shadows of accelerated black holes

    NASA Astrophysics Data System (ADS)

    Grenzebach, Arne; Perlick, Volker; Lämmerzahl, Claus

    2015-06-01

    In an earlier paper, we have analytically determined the photon regions and the shadows of black holes of the Plebański class of metrics which are also known as the Kerr-Newman-NUT-(anti-)de Sitter metrics. These metrics are characterized by six parameters: Mass, spin, electric and magnetic charges, gravitomagnetic NUT charge and the cosmological constant. Here, we extend this analysis to the Plebański-Demiański class of metrics which contains, in addition to these six parameters, the so-called acceleration parameter. All these metrics are axially symmetric and stationary type D solutions to the Einstein-Maxwell equations with a cosmological constant. We derive analytical formulas for the photon regions (i.e. for the regions that contain spherical lightlike geodesics) and for the boundary curve of the shadow as it is seen by an observer at Boyer-Lindquist coordinates (rO, ϑO) in the domain of outer communication. Whereas all relevant formulas are derived for the whole Plebański-Demiański class, we concentrate on the accelerated Kerr metric (i.e. only mass, spin and acceleration parameter are different from zero) when discussing the influence of the acceleration parameter on the photon region and on the shadow in terms of pictures. The accelerated Kerr metric is also known as the rotating C-metric. We discuss how our analytical formulas can be used for calculating the horizontal and vertical angular diameters of the shadow and we estimate these values for the black holes at the center of our Galaxy and at the center of M87.

  6. View of 'Shadow Rock' taken during third extravehicular activity

    NASA Technical Reports Server (NTRS)

    1972-01-01

    Astronaut Charles M. Duke Jr., Apollo 16 lunar module pilot, exposed this view of 'Shadow Rock' with his 70mm Hasselblad camera during the mission's third and final extravehicular activity (EVA-3), on April 23, 1972. This particular stop was referenced as Station #13. The scoop, a geological hand tool, leans against the rock and helps give an idea of the size. Station #13 is a little southeast of the North Ray crater at the Descartes area.

  7. Blending History with Physics: Acoustic Shadows in the Civil War

    NASA Astrophysics Data System (ADS)

    Ross, Charles D.

    1998-04-01

    To spark student interest in and broaden student perspectives of certain physics principles, it is useful to show how these principles have dramatically affected the course of history. In this case, the study of refraction is enhanced by looking at the results of an original study of the causes of acoustic shadows in the U.S. Civil War and their effect on command decisions in important battles.

  8. Acoustic shadows help gleaning bats find prey, but may be defeated by prey acoustic camouflage on rough surfaces

    PubMed Central

    Clare, Elizabeth L; Holderied, Marc W

    2015-01-01

    Perceptual abilities of animals, like echolocating bats, are difficult to study because they challenge our understanding of non-visual senses. We used novel acoustic tomography to convert echoes into visual representations and compare these cues to traditional echo measurements. We provide a new hypothesis for the echo-acoustic basis of prey detection on surfaces. We propose that bats perceive a change in depth profile and an ‘acoustic shadow’ cast by prey. The shadow is more salient than prey echoes and particularly strong on smooth surfaces. This may explain why bats look for prey on flat surfaces like leaves using scanning behaviour. We propose that rather than forming search images for prey, whose characteristics are unpredictable, predators may look for disruptions to the resting surface (acoustic shadows). The fact that the acoustic shadow is much fainter on rougher resting surfaces provides the first empirical evidence for ‘acoustic camouflage’ as an anti-predator defence mechanism. DOI: http://dx.doi.org/10.7554/eLife.07404.001 PMID:26327624

  9. A General Relativistic Null Hypothesis Test with Event Horizon Telescope Observations of the Black Hole Shadow in Sgr A*

    NASA Astrophysics Data System (ADS)

    Psaltis, Dimitrios; Özel, Feryal; Chan, Chi-Kwan; Marrone, Daniel P.

    2015-12-01

    The half opening angle of a Kerr black hole shadow is always equal to (5 ± 0.2)GM/Dc2, where M is the mass of the black hole and D is its distance from the Earth. Therefore, measuring the size of a shadow and verifying whether it is within this 4% range constitutes a null hypothesis test of general relativity. We show that the black hole in the center of the Milky Way, Sgr A*, is the optimal target for performing this test with upcoming observations using the Event Horizon Telescope (EHT). We use the results of optical/IR monitoring of stellar orbits to show that the mass-to-distance ratio for Sgr A* is already known to an accuracy of ∼4%. We investigate our prior knowledge of the properties of the scattering screen between Sgr A* and the Earth, the effects of which will need to be corrected for in order for the black hole shadow to appear sharp against the background emission. Finally, we explore an edge detection scheme for interferometric data and a pattern matching algorithm based on the Hough/Radon transform and demonstrate that the shadow of the black hole at 1.3 mm can be localized, in principle, to within ∼9%. All these results suggest that our prior knowledge of the properties of the black hole, of scattering broadening, and of the accretion flow can only limit this general relativistic null hypothesis test with EHT observations of Sgr A* to ≲10%.

  10. Imaging the supermassive black hole shadow and jet base of M87 with the event horizon telescope

    SciTech Connect

    Lu, Ru-Sen; Fish, Vincent L.; Doeleman, Sheperd S.; Pankratius, Victor; Broderick, Avery E.; Baron, Fabien; Monnier, John D.

    2014-06-20

    The Event Horizon Telescope (EHT) is a project to assemble a Very Long Baseline Interferometry (VLBI) network of millimeter wavelength dishes that can resolve strong field general relativistic signatures near a supermassive black hole. As planned, the EHT will include enough dishes to enable imaging of the predicted black hole 'shadow', a feature caused by severe light bending at the black hole boundary. The center of M87, a giant elliptical galaxy, presents one of the most interesting EHT targets as it exhibits a relativistic jet, offering the additional possibility of studying jet genesis on Schwarzschild radius scales. Fully relativistic models of the M87 jet that fit all existing observational constraints now allow horizon-scale images to be generated. We perform realistic VLBI simulations of M87 model images to examine the detectability of the black shadow with the EHT, focusing on a sequence of model images with a changing jet mass load radius. When the jet is launched close to the black hole, the shadow is clearly visible both at 230 and 345 GHz. The EHT array with a resolution of 20-30 μas resolution (∼2-4 Schwarzschild radii) is able to image this feature independent of any theoretical models and we show that imaging methods used to process data from optical interferometers are applicable and effective for EHT data sets. We demonstrate that the EHT is also capable of tracing real-time structural changes on a few Schwarzschild radii scales, such as those implicated by very high-energy flaring activity of M87. While inclusion of ALMA in the EHT is critical for shadow imaging, the array is generally robust against loss of a station.

  11. Learning in the Shadows and in the Light of Day: A Commentary on "Shadow Education, American Style: Test Preparation, the SAT and College Enrollment"

    ERIC Educational Resources Information Center

    Grodsky, Eric

    2010-01-01

    Buchmann, Condron and Roscigno argue in their article, "Shadow Education, American Style: Test Preparation, the SAT and College Enrollment," that the activities in which students engage to prepare for college entrance exams are forms of shadow education, a means by which more advantaged parents seek to pass their privileged status along to their…

  12. Detection of melamine in milk powders using Near-Infrared Hyperspectral imaging combined with regression coefficient of partial least square regression model

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Illegal use of nitrogen-rich melamine (C3H6N6) to boost perceived protein content of food products such as milk, infant formula, frozen yogurt, pet food, biscuits, and coffee drinks has caused serious food safety problems. Conventional methods to detect melamine in foods, such as Enzyme-linked immun...

  13. A conformational model of per-O-acetyl-cyclomaltoheptaose (-beta-cyclodextrin) in solution: detection of partial inversion of glucopyranose units by NMR spectroscopy.

    PubMed

    Uccello-Barretta, Gloria; Sicoli, Giuseppe; Balzano, Federica; Salvadori, Piero

    2003-05-01

    The stereochemical features of per-O-acetyl-cyclomaltoheptaose (-beta-cyclodextrin) have been investigated in solution by NMR spectroscopy, and the deviation of functionalised glucopyranose rings from 4C(1) chairs to skew-type conformations has been detected. PMID:12706976

  14. Immunoglobulin Mutational Status Detected through Single-Round Amplification of Partial VH Region Represents a Good Prognostic Marker for Clinical Outcome in Chronic Lymphocytic Leukemia

    PubMed Central

    Marasca, Roberto; Maffei, Rossana; Morselli, Monica; Zucchini, Patrizia; Castelli, Ilaria; Martinelli, Silvia; Fontana, Marcella; Ravanetti, Sara; Curotti, Monica; Leonardi, Giovanna; Cagossi, Katia; Partesotti, Giovanni; Torelli, Giuseppe

    2005-01-01

    The immunoglobulin (Ig) mutational status in B-cell chronic lymphocytic leukemia (CLL) distinguishes two subsets of patients with different prognosis. Ig status detection is commonly performed with a panel of VH family-specific primers. Although this method detects clonal VDJ rearrangement in virtually all cases, it is technically cumbersome and therefore not widely used clinically. Here, we describe a simple and rapid method to establish the mutational status of IgVH in CLL. The method is based on a consensus VH FR2 primer, used in both polymerase chain reaction (PCR) and sequencing reactions. Overall, monoclonal B-cell populations were detected in 163 of 189 CLL patients (86%). The prognostic value of IgVH mutational status was then evaluated by analyzing survival in 146 CLL cases using different VH homology cutoffs. CLL prognostic groups were best separated by the classical 98% cutoff: median survival was 127 and 206 months in unmutated and mutated CLL cases, respectively (P = 0.0023). VH FR2 consensus and VH family PCR were compared in 41 cases, correctly assigning all cases by both methods. Therefore, we suggest a sequential strategy to detect immunoglobulin mutational status in CLL patients by first using the approach described in this study followed by alternative VH family-specific PCRs for negative cases. PMID:16258154

  15. Reducing radiation dose to the female breast during CT coronary angiography: A simulation study comparing breast shielding, angular tube current modulation, reduced kV, and partial angle protocols using an unknown-location signal-detectability metric

    SciTech Connect

    Rupcich, Franco; Gilat Schmidt, Taly; Badal, Andreu; Popescu, Lucretiu M.; Kyprianou, Iacovos

    2013-08-15

    Purpose: The authors compared the performance of five protocols intended to reduce dose to the breast during computed tomography (CT) coronary angiography scans using a model observer unknown-location signal-detectability metric.Methods: The authors simulated CT images of an anthropomorphic female thorax phantom for a 120 kV reference protocol and five “dose reduction” protocols intended to reduce dose to the breast: 120 kV partial angle (posteriorly centered), 120 kV tube-current modulated (TCM), 120 kV with shielded breasts, 80 kV, and 80 kV partial angle (posteriorly centered). Two image quality tasks were investigated: the detection and localization of 4-mm, 3.25 mg/ml and 1-mm, 6.0 mg/ml iodine contrast signals randomly located in the heart region. For each protocol, the authors plotted the signal detectability, as quantified by the area under the exponentially transformed free response characteristic curve estimator (A-caret{sub FE}), as well as noise and contrast-to-noise ratio (CNR) versus breast and lung dose. In addition, the authors quantified each protocol's dose performance as the percent difference in dose relative to the reference protocol achieved while maintaining equivalent A-caret{sub FE}.Results: For the 4-mm signal-size task, the 80 kV full scan and 80 kV partial angle protocols decreased dose to the breast (80.5% and 85.3%, respectively) and lung (80.5% and 76.7%, respectively) with A-caret{sub FE} = 0.96, but also resulted in an approximate three-fold increase in image noise. The 120 kV partial protocol reduced dose to the breast (17.6%) at the expense of increased lung dose (25.3%). The TCM algorithm decreased dose to the breast (6.0%) and lung (10.4%). Breast shielding increased breast dose (67.8%) and lung dose (103.4%). The 80 kV and 80 kV partial protocols demonstrated greater dose reductions for the 4-mm task than for the 1-mm task, and the shielded protocol showed a larger increase in dose for the 4-mm task than for the 1-mm task

  16. Development of an ELISA using a recombinant 41 kDa partial protein (P45N') for the detection of Riemerella anatipestifer infections in ducks.

    PubMed

    Huang, Bin; Kwang, Jimmy; Loh, Hilda; Frey, Joachim; Tan, Hai-Meng; Chua, Kim-Lee

    2002-09-24

    Riemerella anatipestifer, a gram-negative bacillus, is the causative agent of duck septicemia, a disease which could incur much economic loss in the duck industry. An indirect enzyme-linked immunosorbent assay (ELISA) has been developed to facilitate early detection of R. anatipestifer infection in ducks. The antigen used was a recombinant 41 kDa N-terminal fragment (rP45N') of a newly characterized R. anatipestifer potential surface protein, P45, which was expressed in Escherichia coli as an N-terminal GST fusion protein. The rP45N'-based ELISA successfully detected P45 antibodies in the sera of 20 ducks immunized with bacterin preparations of R. anatipestifer serotypes 1, 10 15, 19 and the ATCC11845 strain. Antibodies to P45 were also detected in the sera of 25% (75/296) of White Pekin ducks which were imported into Singapore from three different farms. Successful discrimination was obtained between sera from infected ducks and that of specific-pathogen free ducks (p<0.01). The rP45N'-GST antigen did not cross-react with antibodies in sera from guinea pigs which were infected with other gram-negative and gram-positive bacterial pathogens, including Aeromonas hydrophila, Citrobacter freundii, E. coli, Klebsiella pneumoniae, Pastuerella multocida, Proteus mirabilis, Salmonella spp., Serratia maccescens, Shigella sonnei and Yersinia enterocolitica. In addition, the DNA sequence encoding P45 was detected in R. anatipestifer serotypes 1, 2, 3, 4, 5, 6, 7, 8, 9, 11, 14, 15, 16, 17, 18, 19 and the ATCC11845 strain, suggesting that P45 is probably also universally expressed in these R. anatipestifer serotypes. Thus, the ELISA described is applicable to the detection of R. anatipestifer infection in ducks. PMID:12220809

  17. Earth conical shadow modeling for LEO satellite using reference frame transformation technique: A comparative study with existing earth conical shadow models

    NASA Astrophysics Data System (ADS)

    Srivastava, V. K.; Yadav, S. M.; Ashutosh; Kumar, J.; Kushvah, B. S.; Ramakrishna, B. N.; Ekambram, P.

    2015-03-01

    In this article, we propose an Earth conical shadow model predicting umbra and penumbra states for the low Earth orbiting satellite considering the spherical shape of the Earth. The model is described using the umbra and penumbra cone geometries of the Earth's shadow and the geometrical equations of these conical shadow regions into a Sun centered frame. The proposed model is simulated for three polar Sun-synchronous Indian Remote Sensing satellites: Cartosat-2A, Resourcesat-2 and Oceansat-2. The proposed model compares well with the existing spherical Earth conical shadow models such as those given by Vallado (2013), Wertz (2002), Hubaux et al. (2012), and Srivastava et al. (2013, 2014). An assessment is carried out of the existing Earth conical shadow models with Systems Tool Kit (STK), a high fidelity commercial software package of Analytic Graphic Inc., and the real time telemetry data.

  18. Immunohistochemical detection of a novel 22- to 25-kilodalton glycoprotein of Paracoccidioides brasiliensis in biopsy material and partial characterization by using species-specific monoclonal antibodies.

    PubMed Central

    Figueroa, J I; Hamilton, A; Allen, M; Hay, R

    1994-01-01

    Two murine monoclonal antibodies (MAbs) specific to Paracoccidioides brasiliensis (as determined by enzyme-linked immunosorbent assay [ELISA] and Western blot [immunoblot]) were produced by using a modification of standard hybridization protocols, with cyclophosphamide included as an immunomodulator to abolish responses to highly cross-reactive immunodominant epitopes. MAbs PS14 and PS15 are two different clones which exhibit similar characteristics by ELISA and Western blot. They are directed against a 22- to 25-kDa antigen which is present in P. brasiliensis and which could not be identified in other dimorphic fungi by ELISA or Western blot. Partial purification of the antigen was accomplished by isoelectric focusing, and deglycosylation studies suggested that the 22- to 25-kDa antigen is a glycoprotein with a pI of between 4.5 and 5 and that O-linked sugars may be part of the recognized epitope. The MAbs stained the cytoplasm of P. brasiliensis yeast and hyphal cells in cryostat sections of fresh cultures of the fungus. In addition, the MAbs stained the wall of paracoccidioidomycotic granulomas, as well as the cytoplasm of the fungus, as determined by the use of immunofluorescence, immunoperoxidase, and immuno-alkaline phosphatase staining techniques in paraffin-embedded sections of human biopsy material, and they failed to stain granulomas resulting from other clinical conditions. These findings suggest that these MAbs have potential use in the immunohistochemical identification of P. brasiliensis. Images PMID:8077405

  19. Analysis of the Sensitivity of K-Type Molecular Sieve-Deposited MWNTs for the Detection of SF6 Decomposition Gases under Partial Discharge

    PubMed Central

    Zhang, Xiaoxing; Li, Xin; Luo, Chenchen; Dong, Xingchen; Zhou, Lei

    2015-01-01

    Sulfur hexafluoride (SF6) is widely utilized in gas-insulated switchgear (GIS). However, part of SF6 decomposes into different components under partial discharge (PD) conditions. Previous research has shown that the gas responses of intrinsic and 4 Å-type molecular sieve-deposited multi-wall carbon nanotubes (MWNTs) to SOF2 and SO2F2, two important decomposition components of SF6, are not obvious. In this study, a K-type molecular sieve-deposited MWNTs sensor was developed. Its gas response characteristics and the influence of the mixture ratios of gases on the gas-sensing properties were studied. The results showed that, for sensors with gas mixture ratios of 5:1, 10:1, and 20:1, the resistance change rate increased by nearly 13.0% after SOF2 adsorption, almost 10 times that of MWNTs sensors, while the sensors’ resistance change rate with a mixture ratio of 10:1 reached 17.3% after SO2F2 adsorption, nearly nine times that of intrinsic MWNT sensors. Besides, a good linear relationship was observed between concentration of decomposition components and the resistance change rate of sensors. PMID:26569245

  20. Analysis of the Sensitivity of K-Type Molecular Sieve-Deposited MWNTs for the Detection of SF₆ Decomposition Gases under Partial Discharge.

    PubMed

    Zhang, Xiaoxing; Li, Xin; Luo, Chenchen; Dong, Xingchen; Zhou, Lei

    2015-01-01

    Sulfur hexafluoride (SF6) is widely utilized in gas-insulated switchgear (GIS). However, part of SF6 decomposes into different components under partial discharge (PD) conditions. Previous research has shown that the gas responses of intrinsic and 4 Å-type molecular sieve-deposited multi-wall carbon nanotubes (MWNTs) to SOF2 and SO2F2, two important decomposition components of SF6, are not obvious. In this study, a K-type molecular sieve-deposited MWNTs sensor was developed. Its gas response characteristics and the influence of the mixture ratios of gases on the gas-sensing properties were studied. The results showed that, for sensors with gas mixture ratios of 5:1, 10:1, and 20:1, the resistance change rate increased by nearly 13.0% after SOF2 adsorption, almost 10 times that of MWNTs sensors, while the sensors' resistance change rate with a mixture ratio of 10:1 reached 17.3% after SO2F2 adsorption, nearly nine times that of intrinsic MWNT sensors. Besides, a good linear relationship was observed between concentration of decomposition components and the resistance change rate of sensors. PMID:26569245

  1. Ultrasound and Perforated Viscus; Dirty Fluid, Dirty Shadows, and Peritoneal Enhancement

    PubMed Central

    Shokoohi, Hamid; S. Boniface, Keith; M. Abell, Bruce; Pourmand, Ali; Salimian, Mohammad

    2016-01-01

    Early detection of free air in the peritoneal cavity is vital in diagnosis of life-threatening emergencies, and can play a significant role in expediting treatment. We present a series of cases in which bedside ultrasound (US) in the emergency department accurately identified evidence of free intra-peritoneal air and echogenic (dirty) free fluid consistent with a surgical final diagnosis of a perforated hollow viscus. In all patients with suspected perforated viscus, clinicians were able to accurately identify the signs of pneumoperitoneum including enhanced peritoneal stripe sign (EPSS), peritoneal stripe reverberations, and focal air collections associated with dirty shadowing or distal multiple reflections as ring down artifacts. In all cases, hollow viscus perforation was confirmed surgically. It seems that, performing US in patients with suspected perforated viscus can accurately identify presence of intra-peritoneal echogenic or “dirty” free fluid as well as evidence of free air, and may expedite patient management.

  2. Ultrasound and Perforated Viscus; Dirty Fluid, Dirty Shadows, and Peritoneal Enhancement.

    PubMed

    Shokoohi, Hamid; S Boniface, Keith; M Abell, Bruce; Pourmand, Ali; Salimian, Mohammad

    2016-01-01

    Early detection of free air in the peritoneal cavity is vital in diagnosis of life-threatening emergencies, and can play a significant role in expediting treatment. We present a series of cases in which bedside ultrasound (US) in the emergency department accurately identified evidence of free intra-peritoneal air and echogenic (dirty) free fluid consistent with a surgical final diagnosis of a perforated hollow viscus. In all patients with suspected perforated viscus, clinicians were able to accurately identify the signs of pneumoperitoneum including enhanced peritoneal stripe sign (EPSS), peritoneal stripe reverberations, and focal air collections associated with dirty shadowing or distal multiple reflections as ring down artifacts. In all cases, hollow viscus perforation was confirmed surgically. It seems that, performing US in patients with suspected perforated viscus can accurately identify presence of intra-peritoneal echogenic or "dirty" free fluid as well as evidence of free air, and may expedite patient management. PMID:27274522

  3. [Pulmonary malignant fibrous histiocytoma (inflammatory type) showing intracavitary fungus ball-like shadow].

    PubMed

    Kobayashi, T; Takenaka, M; Kido, T; Tanio, Y

    1999-02-01

    We report a rare case of primary malignant fibrous histiocytoma of the lung showing intracavitary fungus ball-like shadows. Fiberoptic bronchoscopy revealed no visible tumor, but adenocarcinoma cells were detected in samples of lavage fluid from the cavitary lesion. Staging procedures (T 2 N 0 M 0) confirmed that there were no metastatic lesions. A complete resection of the left lower lobe was performed. The tumor showed polypoid growth that obstructed a small peripheral bronchus, and formed a cavitary lesion. It was histologically diagnosed as an inflammatory type of malignant fibrous histiocytoma, and consisted of atypical histiocyte-like cells, neutrophils, lymphocytes, foamy cells, and fibroblast-like cells in a storiform pattern. The patient has been in complete remission for 3 years after surgery. PMID:10214047

  4. Energetic ions in the close environment of Mars and particle shadowing by the planet

    NASA Astrophysics Data System (ADS)

    Afonin, V.; Gringauz, K.; McKenna-Lawlor, S.; Kecskemety, K.; Keppler, E.

    1989-10-01

    The twin-telescope particle-detector system, SLED, aboard Phobos 2 recorded flux enhancements in the range 30-350 keV in the same general location in the close environment of Mars, over eight days at about 900 km altitude in three successive elliptical orbits. Here, possible interpretations of these observations are presented. Energy-related particle shadowing by the body of Mars was also detected, and the data indicate that this effect occurred in less than 20 percent of the 114 circular orbits around Mars because of the nutation of the spacecraft. The influence of magnetic fields in allowing particles to reach the detector under potentially screened conditions is discussed.

  5. Shadows bordering the lung on radiographs of normal and obese persons

    PubMed Central

    Gluck, M. C.; Twigg, H. L.; Ball, M. F.; Rhodes, P. G.

    1972-01-01

    The thickness of the shadows that accompany ribs or border the lungs on the chest postero-anterior radiographs of 22 obese patients and 22 normal-weight subjects was measured, when present, at several rib levels. A similar measurement was made of accompanying rib shadows on chest postero-anterior radiographs of eight obese patients after weight reduction. Statistical analysis showed that there were significantly thicker soft tissue shadows adjacent to the ribs of obese subjects compared to normal-weight persons and of obese subjects before as compared to after weight reduction. Such shadows are more frequent and are seen at more rib levels of the obese. In addition, the following pertinent features are discussed: the mechanism by which soft tissue projects a radiographic shadow, the factors affecting its appearance, and the significance of such shadows as a variant of the normal chest radiograph and not as a manifestation of pathology. Images PMID:5034601

  6. Comparison of ISS Power System Telemetry with Analytically Derived Data for Shadowed Cases

    NASA Technical Reports Server (NTRS)

    Fincannon, H. James

    2002-01-01

    Accurate International Space Station (ISS) power prediction requires the quantification of solar array shadowing. Prior papers have discussed the NASA Glenn Research Center (GRC) ISS power system tool SPACE (System Power Analysis for Capability Evaluation) and its integrated shadowing algorithms. On-orbit telemetry has become available that permits the correlation of theoretical shadowing predictions with actual data. This paper documents the comparison of a shadowing metric (total solar array current) as derived from SPACE predictions and on-orbit flight telemetry data for representative significant shadowing cases. Images from flight video recordings and the SPACE computer program graphical output are used to illustrate the comparison. The accuracy of the SPACE shadowing capability is demonstrated for the cases examined.

  7. Cloud-shadow suppression technique for enhancement of Airborne Thematic Mapper imagery

    SciTech Connect

    Guo, L.J.; Moore, J.M. )

    1993-08-01

    Airborne Thematic Mapper (ATM) data are often degraded by the shadows from clouds above the aircraft during the flight. The spectral information in cloud-shadowed areas is reduced but not totally lost because the reflected energy of diffuse illumination (sky light) reaches the sensors from the shadowed ground despite obstruction of direct solar radiation. The thermal band image is almost unaffected by the temporary change of radiation caused by clouds. An enhancement technique for cloud-shadow suppression has been developed based on differencing, RGB-HSI-RGB transformation, and thermal band modulation. The method suppresses cloud shadows with topographic shading retained; spectral information is retrieved and enhanced. The result is a nearly normal color composite with full topographic expression but without cloud shadows. Such a color composite is easy to interpret for geological structures and lithologies. 6 refs.

  8. Message communications of particular message types between compute nodes using DMA shadow buffers

    SciTech Connect

    Blocksome, Michael A.; Parker, Jeffrey J.

    2010-11-16

    Message communications of particular message types between compute nodes using DMA shadow buffers includes: receiving a buffer identifier specifying an application buffer having a message of a particular type for transmission to a target compute node through a network; selecting one of a plurality of shadow buffers for a DMA engine on the compute node for storing the message, each shadow buffer corresponding to a slot of an injection FIFO buffer maintained by the DMA engine; storing the message in the selected shadow buffer; creating a data descriptor for the message stored in the selected shadow buffer; injecting the data descriptor into the slot of the injection FIFO buffer corresponding to the selected shadow buffer; selecting the data descriptor from the injection FIFO buffer; and transmitting the message specified by the selected data descriptor through the data communications network to the target compute node.

  9. The 0.5-2.22 micrometer Scattered Light Spectrum of the Disk around TW Hya: Detection of a Partially Filled Disk Gap at 80 AU*

    NASA Technical Reports Server (NTRS)

    Debes, John H.; Jang-Condell, Hannah; Weinberger, Alycia J.; Roberge, Aki; Schneider, Glenn

    2013-01-01

    We present a 0.5-2.2 micrometer scattered light spectrum of the circumstellar disk around TW Hya from a combination of spatially resolved Hubble Space Telescope STIS spectroscopy and NICMOS coronagraphic images of the disk. We investigate the morphology of the disk at distances greater than 40 AU over this wide range of wavelengths, and identify the presence of a depression in surface brightness at approximately 80 AU that could be caused by a gap in the disk. Additionally, we quantify the surface brightness, azimuthal symmetry, and spectral character of the disk as a function of radius. Our analysis shows that the scattering efficiency of the dust is largely neutral to blue over the observed wavelengths. We model the disk as a steady a-disk with an ad hoc gap structure. The thermal properties of the disk are selfconsistently calculated using a three-dimensional radiative transfer code that uses ray tracing to model the heating of the disk interior and scattered light images. We find a good fit to the data over a wide range of distances from the star if we use a model disk with a partially filled gap of 30% depth at 80 AU and with a self-similar truncation knee at 100 AU. The origin of the gap is unclear, but it could arise from a transition in the nature of the disk's dust composition or the presence of a planetary companion. Based on scalings to previous hydrodynamic simulations of gap-opening criteria for embedded proto-planets, we estimate that a planetary companion forming the gap could have a mass between 6 and 28 solar mass.

  10. THE 0.5-2.22 {mu}m SCATTERED LIGHT SPECTRUM OF THE DISK AROUND TW Hya: DETECTION OF A PARTIALLY FILLED DISK GAP AT 80 AU

    SciTech Connect

    Debes, John H.; Jang-Condell, Hannah; Weinberger, Alycia J.; Roberge, Aki; Schneider, Glenn

    2013-07-01

    We present a 0.5-2.2 {mu}m scattered light spectrum of the circumstellar disk around TW Hya from a combination of spatially resolved Hubble Space Telescope STIS spectroscopy and NICMOS coronagraphic images of the disk. We investigate the morphology of the disk at distances >40 AU over this wide range of wavelengths, and identify the presence of a depression in surface brightness at {approx}80 AU that could be caused by a gap in the disk. Additionally, we quantify the surface brightness, azimuthal symmetry, and spectral character of the disk as a function of radius. Our analysis shows that the scattering efficiency of the dust is largely neutral to blue over the observed wavelengths. We model the disk as a steady {alpha}-disk with an ad hoc gap structure. The thermal properties of the disk are self-consistently calculated using a three-dimensional radiative transfer code that uses ray tracing to model the heating of the disk interior and scattered light images. We find a good fit to the data over a wide range of distances from the star if we use a model disk with a partially filled gap of 30% depth at 80 AU and with a self-similar truncation knee at 100 AU. The origin of the gap is unclear, but it could arise from a transition in the nature of the disk's dust composition or the presence of a planetary companion. Based on scalings to previous hydrodynamic simulations of gap-opening criteria for embedded proto-planets, we estimate that a planetary companion forming the gap could have a mass between 6 and 28 M{sub Circled-Plus }.

  11. Analyzing Spectral Characteristics of Shadow Area from ADS-40 High Radiometric Resolution Aerial Images

    NASA Astrophysics Data System (ADS)

    Hsieh, Yi-Ta; Wu, Shou-Tsung; Chen, Chaur-Tzuhn; Chen, Jan-Chang

    2016-06-01

    The shadows in optical remote sensing images are regarded as image nuisances in numerous applications. The classification and interpretation of shadow area in a remote sensing image are a challenge, because of the reduction or total loss of spectral information in those areas. In recent years, airborne multispectral aerial image devices have been developed 12-bit or higher radiometric resolution data, including Leica ADS-40, Intergraph DMC. The increased radiometric resolution of digital imagery provides more radiometric details of potential use in classification or interpretation of land cover of shadow areas. Therefore, the objectives of this study are to analyze the spectral properties of the land cover in the shadow areas by ADS-40 high radiometric resolution aerial images, and to investigate the spectral and vegetation index differences between the various shadow and non-shadow land covers. According to research findings of spectral analysis of ADS-40 image: (i) The DN values in shadow area are much lower than in nonshadow area; (ii) DN values received from shadowed areas that will also be affected by different land cover, and it shows the possibility of land cover property retrieval as in nonshadow area; (iii) The DN values received from shadowed regions decrease in the visible band from short to long wavelengths due to scattering; (iv) The shadow area NIR of vegetation category also shows a strong reflection; (v) Generally, vegetation indexes (NDVI) still have utility to classify the vegetation and non-vegetation in shadow area. The spectral data of high radiometric resolution images (ADS-40) is potential for the extract land cover information of shadow areas.

  12. Partial pressure analysis of plasmas

    SciTech Connect

    Dylla, H.F.

    1984-11-01

    The application of partial pressure analysis for plasma diagnostic measurements is reviewed. A comparison is made between the techniques of plasma flux analysis and partial pressure analysis for mass spectrometry of plasmas. Emphasis is given to the application of quadrupole mass spectrometers (QMS). The interface problems associated with the coupling of a QMS to a plasma device are discussed including: differential-pumping requirements, electromagnetic interferences from the plasma environment, the detection of surface-active species, ion source interactions, and calibration procedures. Example measurements are presented from process monitoring of glow discharge plasmas which are useful for cleaning and conditioning vacuum vessels.

  13. Signal-to-noise ratio requirements for detection of multiple pulses subject to partially correlated fading with chi-squared statistics of various degrees of freedom

    NASA Astrophysics Data System (ADS)

    Nuttall, Albert H.; Eby, Edward S.

    1986-06-01

    The transmitted signal in a fading medium is composed of several pulses separated in time so as to achieve diversity and thereby combat deep fades and loss of signal. Receiver processing consists of matched filtering of each of the pulses, followed by summation of the squared envelopes of all the filter outputs. In addition to additive Gaussian background noise, the signal is subject to slow medium fading which has a chi-squared first-order distribution and which may be correlated from pulse to pulse to an arbitrary degree. The false alarm and detection probabilities of this system are derived in various series expansions which are amenable to efficient computer evaluation. Programs are presented and exercised for various combinations of signal-to-noise ratio, number of pulses, degree of correlated fading, and (noninteger) number of degrees of freedom of the chi-squared fading. Required input signal-to-noise ratios for several false alarm and detection probabilities are computed and plotted for cases of the fading normalized correlation coefficient ranging from 0 to 1; results for a nonfading medium are superposed for easy comparison. Special cases are dependent and independent Rayleigh amplitude fading.

  14. Rapid photometric detection of thymine residues partially flipped out of double helix as a method for direct scanning of point mutations and apurinic DNA sites.

    PubMed

    Logvina, N A; Yakubovskaya, M G; Dolinnaya, N G

    2011-02-01

    A spectroscopic assay for detection of extrahelical thymine residues in DNA heteroduplexes under their modification by potassium permanganate has been developed. The assay is based on increase in absorbance at 420 nm due to accumulation of thymidine oxidation intermediates and soluble manganese dioxide. The analysis was carried out using a set of 19-bp DNA duplexes containing unpaired thymidines opposite tetrahydrofuranyl derivatives mimicking a widespread DNA damage (apurinic (AP) sites) and a library of 50-bp DNA duplexes containing all types of base mismatches in different surroundings. The relation between the selectivity of unpaired T oxidation and the thermal stability of DNA double helix was investigated. The method described here was shown to discriminate between DNA duplexes with one or two AP sites and to reveal thymine-containing mismatches and all noncanonical base pairs in AT-surroundings. Comparative results of CCM analysis and the rapid photometric assay for mismatch detection are demonstrated for the first time in the same model system. The chemical reactivity of target thymines was shown to correlate with local disturbance of double helix at the mismatch site. As the spectroscopic assay does not require the DNA cleavage reaction and gel electrophoresis, it can be easily automated and used for primary screening of somatic mutations. PMID:21568858

  15. Effect of shadowing on electromagnetic scattering from rough ocean wavelike surfaces at small grazing angles

    SciTech Connect

    West, J.C.

    1997-03-01

    A hybrid moment-method/geometrical-theory-of-diffraction technique (MM/GTD) has been implemented to numerically calculate the electromagnetic scattering from one-dimensionally rough surfaces at extreme illumination angles (down to 0{degree} grazing). The hybrid approach allows the extension of the modeled scattering surface to infinity, avoiding the artificial edge diffraction that prevents use of the standard moment method at the smallest grazing angles. Numerical calculation of the backscattering from slightly rough large-scale surfaces approximating ocean wave features shows that roughness in strongly shadowed regions can contribute significantly to the total backscatter at vertical polarization. This is observed when the shadowing obstacle is several wavelengths high, and the magnitude of the shadow-region contribution does not depend on the radius-of-curvature of the shadowing feature. Strongly shadowed roughness does not significantly contribute to the backscatter at horizontal polarization, although weakly shadowed roughness near the incidence shadow boundary does. The calculations indicate that a shadowing-corrected two-scale model may be able to predict the distributed-surface portion of the sea-surface scattering from the ocean surface at grazing angles down to about 15{degree}, but at lower grazing the shadowing and large-scale curvature of the surface prevent the establishment of a Bragg resonance and invalidate the model.

  16. Photoreception in a barnacle: electrophysiology of the shadow reflex pathway in Balanus cariosus.

    PubMed

    Millecchia, R; Gwilliam, G F

    1972-08-01

    The photoreceptors in the median ocellus of the rock barnacle depolarize when illuminated. This depolarization spreads passively to the axon terminals in the supraesophageal ganglion. A small number of cells in the supraesophageal ganglion hyperpolarize when the median ocellus is illuminated and depolarize when it is shadowed. Nerve impulses are superimposed on the slow depolarization of the ganglion cells. Impulse activity in response to shadowing the median ocellus is recorded in a few fibers of the circumesophageal connectives. Picrotoxin blocks this shadow-induced activity. A model of the shadow reflex pathway is presented. PMID:4339616

  17. Effect of shadowing on initial conditions, transverse energy and hard probes in ultrarelativistic heavy ion collisions

    SciTech Connect

    Emel'yanov, V.; Khodinov, A.; Klein, S.R.; Vogt, R.

    1999-10-05

    The effect of shadowing on the early state of ultrarelativistic heavy ion collisions is investigated along with transverse energy and hard process production, specifically Drell-Yan, J/psi, and Upsilon production. We choose several parton distributions and parameterizations of nuclear shadowing, as well as the spatial dependence of shadowing, to study the influence of shadowing on relevant observables. Results are presented for Au+Au collisions at sqrt(s{sub NN}) = 200 GeV and Pb+Pb collisions at sqrt(s{sub NN}) =5.5 TeV.

  18. International Space Station Power System Telemetry Compared With Analytically Derived Data for Shadowed Cases

    NASA Technical Reports Server (NTRS)

    Fincannon, H. James

    2003-01-01

    This article highlights fiscal year 2002 work performed by NASA Glenn Research Center personnel to validate algorithms and data developed in-house to predict shadowing effects on the International Space Station (ISS) solar arrays power generation. The validation effort utilized video footage and on-orbit telemetry for cases spanning a 1-yr period. Validation was required because of the uncertainty of various aspects involved in shadowing analysis. Results show that a good comparison exists between actual and predicted shadowed power system performance for solar array front and backside shadowing.

  19. Pacman in the sky with shadows: the effect of cast shadows on the perceptual completion of occluded figures by chimpanzees and humans

    PubMed Central

    2010-01-01

    Background Humans readily perceive whole shapes as intact when some portions of these shapes are occluded by another object. This type of amodal completion has also been widely reported among nonhuman animals and is related to pictorial depth perception. However, the effect of a cast shadow, a critical pictorial-depth cue for amodal completion has been investigated only rarely from the comparative-cognitive perspective. In the present study, we examined this effect in chimpanzees and humans. Results Chimpanzees were slower in responding to a Pacman target with an occluding square than to the control condition, suggesting that participants perceptually completed the whole circle. When a cast shadow was added to the square, amodal completion occurred in both species. On the other hand, however, critical differences between the species emerged when the cast shadow was added to the Pacman figure, implying that Pacman was in the sky casting a shadow on the square. The cast shadow prevented, to a significant extent, compulsory amodal completion in humans, but had no effect on chimpanzees. Conclusion These results suggest that cast shadows played a critical role in enabling humans to infer the spatial relationship between Pacman and the square. For chimpanzees, however, a cast shadow may be perceived as another "object". A limited role for cast shadows in the perception of pictorial depth has also been reported with respect to human cognitive development. Further studies on nonhuman primates using a comparative-developmental perspective will clarify the evolutionary origin of the role of cast shadows in visual perception. PMID:20615212

  20. Robust lane sensing and departure warning under shadows and occlusions.

    PubMed

    Tapia-Espinoza, Rodolfo; Torres-Torriti, Miguel

    2013-01-01

    A prerequisite for any system that enhances drivers' awareness of road conditions and threatening situations is the correct sensing of the road geometry and the vehicle's relative pose with respect to the lane despite shadows and occlusions. In this paper we propose an approach for lane segmentation and tracking that is robust to varying shadows and occlusions. The approach involves color-based clustering, the use of MSAC for outlier removal and curvature estimation, and also the tracking of lane boundaries. Lane boundaries are modeled as planar curves residing in 3D-space using an inverse perspective mapping, instead of the traditional tracking of lanes in the image space, i.e., the segmented lane boundary points are 3D points in a coordinate frame fixed to the vehicle that have a depth component and belong to a plane tangent to the vehicle's wheels, rather than 2D points in the image space without depth information. The measurement noise and disturbances due to vehicle vibrations are reduced using an extended Kalman filter that involves a 6-DOF motion model for the vehicle, as well as measurements about the road's banking and slope angles. Additional contributions of the paper include: (i) the comparison of textural features obtained from a bank of Gabor filters and from a GMRF model; and (ii) the experimental validation of the quadratic and cubic approximations to the clothoid model for the lane boundaries. The results show that the proposed approach performs better than the traditional gradient-based approach under different levels of difficulty caused by shadows and occlusions. PMID:23478598

  1. Robust Lane Sensing and Departure Warning under Shadows and Occlusions

    PubMed Central

    Tapia-Espinoza, Rodolfo; Torres-Torriti, Miguel

    2013-01-01

    A prerequisite for any system that enhances drivers' awareness of road conditions and threatening situations is the correct sensing of the road geometry and the vehicle's relative pose with respect to the lane despite shadows and occlusions. In this paper we propose an approach for lane segmentation and tracking that is robust to varying shadows and occlusions. The approach involves color-based clustering, the use of MSAC for outlier removal and curvature estimation, and also the tracking of lane boundaries. Lane boundaries are modeled as planar curves residing in 3D-space using an inverse perspective mapping, instead of the traditional tracking of lanes in the image space, i.e., the segmented lane boundary points are 3D points in a coordinate frame fixed to the vehicle that have a depth component and belong to a plane tangent to the vehicle's wheels, rather than 2D points in the image space without depth information. The measurement noise and disturbances due to vehicle vibrations are reduced using an extended Kalman filter that involves a 6-DOF motion model for the vehicle, as well as measurements about the road's banking and slope angles. Additional contributions of the paper include: (i) the comparison of textural features obtained from a bank of Gabor filters and from a GMRF model; and (ii) the experimental validation of the quadratic and cubic approximations to the clothoid model for the lane boundaries. The results show that the proposed approach performs better than the traditional gradient-based approach under different levels of difficulty caused by shadows and occlusions. PMID:23478598

  2. Diffraction off nuclei in color singlet models of shadowing

    NASA Astrophysics Data System (ADS)

    Frankfurt, L. L.; Strikman, M. I.

    1996-02-01

    The assumption that only color singlet interactions between projectiles and nucleons in nuclei are relevant for the nuclear shadowing and the AGK cutting rules are used to estimate the cross section of diffraction and the multiplicity fluctuations for eA scattering at HERA energies. We find that for sufficiently light nuclei, A ≤ 20, the result only weakly depends on the details of the model, and that a large fraction of events is expected to be of diffractive nature. At the same time, a significant fraction of non-diffractive events should have multiplicities much larger than those observed in ep scattering.

  3. Extreme Access & Lunar Ice Mining in Permanently Shadowed Craters Project

    NASA Technical Reports Server (NTRS)

    Mueller, Robert P.

    2014-01-01

    Results from the recent LCROSS mission in 2010, indicate that H2O ice and other useful volatiles such as CO, He, and N are present in the permanently shadowed craters at the poles of the moon. However, the extreme topography and steep slopes of the crater walls make access a significant challenge. In addition temperatures have been measured at 40K (-233 C) so quick access and exit is desirable before the mining robot cold soaks. The Global Exploration Roadmap lists extreme access as a necessary technology for Lunar Exploration.

  4. Greenland Telescope: Imaging Black Hole Shadow and THz Astronomy

    NASA Astrophysics Data System (ADS)

    Matsushita, Satoki; Asada, Keiichi; Blundell, Ray; Chang, Chih-Cheng; Chen, Ming-Tang; Grimes, Paul; Han, Johnson; Hirashita, Hiroyuki; Ho, Paul T. P.; Huang, Ted; Inoue, Makoto; Jiang, Homin; Koch, Patrick; Kubo, Derek; Martin-Cocher, Pierre; Meyer-Zhao, Zheng; Nakamura, Masanori; Nishioka, Hiroaki; Nystrom, George; Paine, Scott; Patel, Nimesh; Pu, Hung-Yi; Raffin, Philippe; Snow, William; Srinivasan, Ranjani

    2015-08-01

    Direct imaging of a black hole shadow is one of the ultimate goals for the modern physics and astronomy. Primary science goal of this Greenland Telescope (GLT) project is to directly image the black hole shadow of M87 (Virgo A) using the submillimeter (submm) very long baseline interferometry (VLBI) technique. The size of the black hole shadow is expected to be around 40 micro-arcsec, and submm VLBI is the only technology available to reach this spatial resolution so far. This project is to bring the retrofitted Atacama Large Millimeter/submm Array (ALMA) North America prototype antenna to Greenland Summit, and perform submm VLBI. GLT together with the phase-up ALMA makes the longest baseline of more than 9000 km, or around 20 micro-arcsec at 350 GHz, which enables to resolve the shadow of the black hole.In addition to the primary goal, since the observational condition at the Greenland Summit is expected to be good, we are aiming for the THz astronomy using single-dish mode (while antenna is not performing VLBI observations). We are currently studying the possible science projects.We have already installed a 225 GHz tipping radiometer at the Greenland Summit on Aug. 2011, and taking the opacity data for more than 3 years. The data show that the site is good enough for submm VLBI observations, and indeed possible to perform THz single-dish observations for about 10% of winter time.Various antenna components are mostly refurbished or re-designed for the extremely cold weather conditions at the Greenland Summit. Receivers for the VLBI and single-dish observations are also under development. We are planning to bring the antenna soon to Thule, an US airforce base located at the north-west coast of Greenland, for the antenna re-assembly and various tests, and some initial science observations until the Summit Station is ready. Then, we bring the antenna to the final site. In this talk, we will present the current status of the GLT project.

  5. Nuclear Shadowing and Select d+Au Observables

    NASA Astrophysics Data System (ADS)

    Adeluyi, Adeola; Fai, George

    2007-04-01

    Much of the complexity of the description of d+Au collisions in the framework of perturbative Quantum Chromodynamics (pQCD) derives from effects of the nuclear environment. Here we investigate the effects of the most recent available nuclear shadowing parametrization, the Hirai-Kumano-Nagai (HKN) nuclear parton distribution functions (nPDFs) and the updated Albino-Kniehl-Kramer (AKK) fragmentation functions on three select d+Au collision observables. We compare our results to available experimental data from the STAR and BRAHMS collaborations.

  6. Observation-point-dependent blocking shadows on a reflector antenna

    NASA Astrophysics Data System (ADS)

    Rusch, Willard V. T.; Welch, Lloyd R.; Mires, George E.

    1989-06-01

    The authors present efficient algorithms that can be incorporated in a physical-optics integration to account for migrating feed- and observation-point-dependent geometrical shadows caused by obstacles in the aperture of a reflector antenna with the feed under focused or scanned conditions. The expressions involve only addition and multiplication of simple low-order polynomials and hence do not introduce expensive overhead into the numerical integration. Obstacle shapes considered are disks, polygons, cylinders, and polyhedrons. Some appropriate diffraction corrections are presented which are compatible with the blocking algorithms.

  7. Detection and partial genetic characterisation of a novel variant of Avian nephritis virus in Indian poultry flocks showing diverse clinical signs.

    PubMed

    Gowthaman, Vasudevan; Singh, Sambu; Dhama, Kuldeep; Barathidasan, Rajamani; Srinivasan, Palani; Saravanan, Sellappan; Gopalakrishnamurthy, Thippichettypalayam; Deb, Rajib; Mathapati, Basavaraj; Ramakrishnan, Muthannan

    2015-12-01

    Avian nephritis virus (ANV) infects poultry flocks worldwide, but no confirmed cases have been reported from India so far. In the current study, disease investigation was carried out in 21 broiler flocks at different parts of India with clinical signs of nephritis, uneven and stunted growth, diarrhoea, reduced body weight, and mortality up to 9.72%. Out of the 21 flocks screened, two were found positive for ANV in RT-PCR assay. BLAST analysis revealed that the ANV of Indian origin was closely related to ANV-1 strains reported from Japan, Hungary and China. However, comparison of a small portion (~12% of nucleotides, i.e. ~60 nts, common site for ANV-1 and ANV-3, position 2200-2260 of ORF 1a gene) of the Indian ANV sequence with ANV-3 sequences revealed 89-93% identities with different ANV-3 isolates. Phylogenetically, ANV-1 forms three clades, and the Indian ANV clustered under clade II. This study confirms the existence of ANV in Indian poultry flocks and is the first report on the molecular detection and genetic characterisation of ANV from India. PMID:26599096

  8. Detection, partial purification and characterization of bacteriocin produced by Lactobacillus brevis FPTLB3 isolated from freshwater fish: Bacteriocin from Lb. brevis FPTLB3.

    PubMed

    Banerjee, Shiba Prosad; Dora, Krushna Chandra; Chowdhury, Supratim

    2013-02-01

    Lactobacillus brevis FPTLB3 was isolated from freshwater fish, capable of producing bacteriocin that had broad spectrum of inhibition (3200 AU/ml) against Escherichia coli MTCC 1563, Enterococcus faecalis MTCC 2729, Lactobacillus casei MTCC 1423, Lactobacillus sakei ATCC 15521 and Staphylococcus aureus ATCC 25923. The antimicrobial activity of crude supernatant fluid was stable after heating at 121 °C for 60 min and declined thereafter. Stability of antimicrobial activity was observed at pH range of 2.0 to 8.0. Its active principle was proteinaceous in nature since the bacteriocin was inactivated by proteolytic enzymes, but not by other non-proteolytic enzymes. Mitomycin C and UV light did not affect the activity of the bacteriocin, while chloroform extraction completely destroyed their activity. Exposure to surfactant resulted in an increase in titre, except Nonidet P-40, which led to total loss of activity. No bacteriocin adsorption was detected at pH 1 to 2, whereas 100% bacteriocin adsorption was found at pH 6.5. Based on Tricine SDS-PAGE the estimated molecular mass of bacteriocin was 54 kDa. No plasmid was found to present in the isolate. PMID:24425883

  9. Partial (focal) seizure

    MedlinePlus

    ... Jacksonian seizure; Seizure - partial (focal); Temporal lobe seizure; Epilepsy - partial seizures ... Abou-Khalil BW, Gallagher MJ, Macdonald RL. Epilepsies. In: Daroff RB, ... 6th ed. Philadelphia, PA: Elsevier Saunders; 2012:chap 67. ...

  10. Partial (focal) seizure

    MedlinePlus

    ... Jacksonian seizure; Seizure - partial (focal); Temporal lobe seizure; Epilepsy - partial seizures ... Abou-Khalil BW, Gallagher MJ, Macdonald RL. Epilepsies. In: Daroff ... Practice . 7th ed. Philadelphia, PA: Elsevier; 2016:chap 101. ...

  11. Partial tooth gear bearings

    NASA Technical Reports Server (NTRS)

    Vranish, John M. (Inventor)

    2010-01-01

    A partial gear bearing including an upper half, comprising peak partial teeth, and a lower, or bottom, half, comprising valley partial teeth. The upper half also has an integrated roller section between each of the peak partial teeth with a radius equal to the gear pitch radius of the radially outwardly extending peak partial teeth. Conversely, the lower half has an integrated roller section between each of the valley half teeth with a radius also equal to the gear pitch radius of the peak partial teeth. The valley partial teeth extend radially inwardly from its roller section. The peak and valley partial teeth are exactly out of phase with each other, as are the roller sections of the upper and lower halves. Essentially, the end roller bearing of the typical gear bearing has been integrated into the normal gear tooth pattern.

  12. Partial Spreading of a Laser Beam into a Light Sheet by Shock Waves and Its Use as a Shock Detection Technique

    NASA Technical Reports Server (NTRS)

    Panda, J.

    1994-01-01

    It is observed that when a laser beam is allowed to fall on a shock surface at a grazing incidence, a small part of the beam spreads out in a thin, diverging sheet of light normal to the surface, and both upstream and downstream of the shock. The phenomenon is visualized by observing a cross section of the light sheet on a screen placed normal to the laser path after it touches a shock. The light sheet disappears when the beam is moved to any other locations where there is no shock or the beam pierces the shock surface, i.e., at a non-grazing incidence. The spread angle of the light sheet is considerably higher than the angle by which the beam may bend as it passes through the shock, which produces a small difference of refractive index. Various details indicate that the spread light is a result of diffraction of a small part of the laser beam by the shock whose thickness is nearly the same as that of the laser wavelength. Shocks formed in underexpanded free jets of fully expanded Mach numbers 1.4 to 1.8 are used for this experiment. The above optical phenomenon is used as the basis of a novel shock detection technique which depends on sensing the spread light using a photomultiplier tube (PMT). The locations of the shock surfaces in the underexpanded supersonic jet, obtained using this technique, match with those inferred from the Schlieren photographs and velocity measurements. Moreover, if the shock oscillates, a periodic PMT signal is obtained which provides information about the frequency and amplitude of shock motion.

  13. How Cold are the Floors of Lunar Polar Shadowed Craters?

    NASA Technical Reports Server (NTRS)

    Mendell, Wendell W.

    2010-01-01

    Almost five decades ago Watson, et al, [1] speculated that molecules of volatile species might accumulate within the cryogenic environments of permanently shadowed polar craters. The subject was largely a scientific curiosity until recently. In the mid-1980's, people began to seriously discuss the feasibility of long-term or permanent human settlement of the Moon. Given that the Moon was known be missing the compounds need to support life and that importing volatiles from Earth is prohibitively expensive, lunar colonists were pictured as processing the putative polar volatiles. A bistatic radar experiment performed with the Clementine spacecraft was interpreted to suggest the presence of large quantities of ice at some polar locations. [2] The neutron spectrometer aboard the Lunar Prospector spacecraft reported high concentrations of hydrogen in the polar regolith, [3] and some interpretations of the data set pointed to very high concentrations in permanently shadowed craters. The reformulation of civilian space policy in 2004, known as the Vision for Space Exploration, emphasized lunar exploration with eye toward development of economic returns from cislunar space and long-tern human presence on the Moon. The theme of finding lunar resources was an impetus for the inclusion of the Diviner Lunar Radiometer Experiment on the Lunar Reconnaissance Orbiter. Preliminary results from Diviner report an unexpectedly low temperature down to 35K in the depths of some craters. [4

  14. Testing the Concept of Drift Shadow at Yucca Mountain, Nevada

    SciTech Connect

    J.B. Paces; L.A. Neymark; T. Ghezzehei; P.F. Dobson

    2006-03-10

    If proven, the concept of drift shadow, a zone of reduced water content and slower ground-water travel time beneath openings in fractured rock of the unsaturated zone, may increase performance of a proposed geologic repository for high-level radioactive waste at Yucca Mountain. To test this concept under natural-flow conditions present in the proposed repository horizon, isotopes within the uranium-series decay chain (uranium-238, uranium-234, and thorium-230, or {sup 238}U-{sup 234}U-{sup 230}Th) have been analyzed in samples of rock from beneath four naturally occurring lithophysal cavities. All samples show {sup 234}U depletion relative to parent {sup 238}U, indicating varying degrees of water-rock interaction over the past million years. Variations in {sup 234}U/{sup 238}U activity ratios indicate that depletion of {sup 234}U relative to {sup 238}U can be either smaller or greater in rock beneath cavity floors relative to rock near cavity margins. These results are consistent with the concept of drift shadow and with numerical simulations of meter-scale spherical cavities in fractured tuff. Differences in distribution patterns of {sup 234}U/{sup 238}U activity ratios in rock beneath the cavity floors are interpreted to reflect differences in the amount of past seepage into lithophysal cavities, as indicated by the abundance of secondary mineral deposits present on the cavity floors.

  15. Testing the concept of drift shadow at Yucca Mountain, Nevada

    USGS Publications Warehouse

    Paces, J.B.; Neymark, L.A.; Ghezzehei, T.; Dobson, P.F.

    2006-01-01

    If proven, the concept of drift shadow, a zone of reduced water content and slower ground-water travel time beneath openings in fractured rock of the unsaturated zone, may increase performance of a proposed geologic repository for high-level radioactive waste at Yucca Mountain, To test this concept under natural-flow conditions present in the proposed repository horizon, isotopes within the uranium-series decay chain (uranium-238, uranium-234, and thorium-230, or 238U-234U-230Th) have been analyzed in samples of rock from beneath four naturally occurring lithophysal cavities. All rock samples show 234U depletion relative to parent 238U indicating varying degrees of water-rock interaction over the past million years. Variations in 234U/238U activity ratios indicate that depletion of 234U relative to 238U can be either smaller or greater in rock beneath cavity floors relative to rock near cavity margins. These results are consistent with the concept of drift shadow and with numerical simulations of meter-scale spherical cavities in fractured tuff. Differences in distribution patterns of 234U/ 238U activity ratios in rock beneath the cavity floors are interpreted to reflect differences in the amount of past seepage into lithophysal cavities, as indicated by the abundance of secondary mineral deposits present on the cavity floors.

  16. PLANET SHADOWS IN PROTOPLANETARY DISKS. II. OBSERVABLE SIGNATURES

    SciTech Connect

    Jang-Condell, Hannah

    2009-07-20

    We calculate simulated images of disks perturbed by embedded small planets. These 10-50 M{sub +} bodies represent the growing cores of giant planets. We examine scattered light and thermal emission from these disks over a range of wavelengths, taking into account the wavelength-dependent opacity of dust in the disk. We also examine the effect of inclination on the observed perturbations. We find that the perturbations are best observed in the visible to mid-infrared (mid-IR). Scattered light images reflect shadows produced at the surface of perturbed disks, while the infrared images follow thermal emission from the surface of the disk, showing cooled/heated material in the shadowed/brightened regions. At still longer wavelengths in the submillimeter, the perturbation fades as the disk becomes optically thin and surface features become overwhelmed by emission closer toward the midplane of the disk. With the construction of telescopes such as TMT, GMT, and ALMA due in the next decade, there is a real possibility of observing planets forming in disks in the optical and submillimeter. However, having the angular resolution to observe the features in the mid-IR will remain a challenge.

  17. Shadow-band correction for diffuse ultraviolet radiation measurements

    NASA Astrophysics Data System (ADS)

    SáNchez, G.; Serrano, A.; Cancillo, M. L.

    2013-05-01

    the correction of shadow-band solar total diffuse measurements has been extensively studied, the case of diffuse ultraviolet measurements has not been properly addressed. This study analyzes the correction factor to be applied to experimental measurements performed adapting a shadow-band to a UV radiometer at a radiometric station in Badajoz (Spain). Three different models, based on approaches widely used for correcting total diffuse measurements, have been revised and adapted for the ultraviolet spectral range. Results reveal that some aspects of the correction proposed for total diffuse radiation are not suitable for ultraviolet diffuse radiation. The mathematical expressions are consequently modified to match the behavior in the ultraviolet range. Thus, three correction models particularized for ultraviolet diffuse measurements are proposed and validated against experimental data. The two models adapted from the original expressions proposed by Battles et al., and Steven show the best performance, with rRMSE of 2.74% and 2.20% and rMBE of 1.53% and 0.46%, respectively.

  18. Verbal Shadowing and Visual Interference in Spatial Memory

    PubMed Central

    Meilinger, Tobias; Bülthoff, Heinrich H.

    2013-01-01

    Spatial memory is thought to be organized along experienced views and allocentric reference axes. Memory access from different perspectives typically yields V-patterns for egocentric encoding (monotonic decline in performance along with the angular deviation from the experienced perspectives) and W-patterns for axes encoding (better performance along parallel and orthogonal perspectives than along oblique perspectives). We showed that learning an object array with a verbal secondary task reduced W-patterns compared with learning without verbal shadowing. This suggests that axes encoding happened in a verbal format; for example, by rows and columns. Alternatively, general cognitive load from the secondary task prevented memorizing relative to a spatial axis. Independent of encoding, pointing with a surrounding room visible yielded stronger W-patterns compared with pointing with no room visible. This suggests that the visible room geometry interfered with the memorized room geometry. With verbal shadowing and without visual interference only V-patterns remained; otherwise, V- and W-patterns were combined. Verbal encoding and visual interference explain when W-patterns can be expected alongside V-patterns and thus can help in resolving different performance patterns in a wide range of experiments. PMID:24019953

  19. A step-wise steerable source of illumination for low-noise "Violin-Mode" shadow sensors, intended for use in interferometric gravitational wave detectors.

    PubMed

    Lockerbie, N A; Tokmakov, K V

    2016-01-01

    A steerable low-noise source of illumination is described for shadow-sensors having a displacement sensitivity of ∼100 pm (rms)/√Hz, at 500 Hz, over a measuring span of at least ±0.5 mm. These sensors were designed to detect lateral "Violin-Mode" resonances in the highly tensioned fused-silica suspension fibres of the test-masses/mirrors for the Advanced Laser Interferometer Gravitational Wave Observatory gravitational wave detectors. The shadow sensors-one intended for each of the four fibres in a suspension-comprised a source of Near InfraRed (NIR) radiation (emitter) and a differential shadow-displacement sensor (detector), these bracketing the fibre under test. The suspension fibres themselves were approximately 600 mm long by 0.4 mm in diameter, and when illuminated from the side, they cast narrow, vertical, shadows onto their respective detectors-these being located at an effective distance of 50 fibre diameters behind the axes of the fibres themselves. The emitter described here was designed to compensate for a significant degree of mechanical drift or creep over time in the mean position of its suspension fibre. This was achieved by employing five adjacent columns of 8  × miniature NIR LEDs (Light Emitting Diodes, λ = 890 nm), with one column being activated at a time. When used in conjunction with a "reverse Galilean" telescope, the LED sources allowed the collimated beam from the emitter to be steered azimuthally in fine angular increments (0.65°), causing the fibre's shadow to move laterally, in a step-wise manner, across the plane of its facing detector. Each step in shadow position was approximately 0.23 mm in size, and this allowed the fibre's shadow to be re-centred, so as to bridge once again both elements of its photodiode detector-even if the fibre was off-centred by as much as ±0.5 mm. Re-centring allowed Violin-Mode vibrations of the fibre to be sensed once again as differential AC photocurrents, these flowing in anti-phase in the two

  20. A step-wise steerable source of illumination for low-noise "Violin-Mode" shadow sensors, intended for use in interferometric gravitational wave detectors

    NASA Astrophysics Data System (ADS)

    Lockerbie, N. A.; Tokmakov, K. V.

    2016-01-01

    A steerable low-noise source of illumination is described for shadow-sensors having a displacement sensitivity of ˜100 pm (rms)/√Hz, at 500 Hz, over a measuring span of at least ±0.5 mm. These sensors were designed to detect lateral "Violin-Mode" resonances in the highly tensioned fused-silica suspension fibres of the test-masses/mirrors for the Advanced Laser Interferometer Gravitational Wave Observatory gravitational wave detectors. The shadow sensors—one intended for each of the four fibres in a suspension—comprised a source of Near InfraRed (NIR) radiation (emitter) and a differential shadow-displacement sensor (detector), these bracketing the fibre under test. The suspension fibres themselves were approximately 600 mm long by 0.4 mm in diameter, and when illuminated from the side, they cast narrow, vertical, shadows onto their respective detectors—these being located at an effective distance of 50 fibre diameters behind the axes of the fibres themselves. The emitter described here was designed to compensate for a significant degree of mechanical drift or creep over time in the mean position of its suspension fibre. This was achieved by employing five adjacent columns of 8 × miniature NIR LEDs (Light Emitting Diodes, λ = 890 nm), with one column being activated at a time. When used in conjunction with a "reverse Galilean" telescope, the LED sources allowed the collimated beam from the emitter to be steered azimuthally in fine angular increments (0.65°), causing the fibre's shadow to move laterally, in a step-wise manner, across the plane of its facing detector. Each step in shadow position was approximately 0.23 mm in size, and this allowed the fibre's shadow to be re-centred, so as to bridge once again both elements of its photodiode detector—even if the fibre was off-centred by as much as ±0.5 mm. Re-centring allowed Violin-Mode vibrations of the fibre to be sensed once again as differential AC photocurrents, these flowing in anti-phase in the

  1. Regulatory Elements of the Floral Homeotic Gene AGAMOUS Identified by Phylogenetic Footprinting and ShadowingW⃞

    PubMed Central

    Hong, Ray L.; Hamaguchi, Lynn; Busch, Maximilian A.; Weigel, Detlef

    2003-01-01

    In Arabidopsis thaliana, cis-regulatory sequences of the floral homeotic gene AGAMOUS (AG) are located in the second intron. This 3-kb intron contains binding sites for two direct activators of AG, LEAFY (LFY) and WUSCHEL (WUS), along with other putative regulatory elements. We have used phylogenetic footprinting and the related technique of phylogenetic shadowing to identify putative cis-regulatory elements in this intron. Among 29 Brassicaceae species, several other motifs, but not the LFY and WUS binding sites identified previously, are largely invariant. Using reporter gene analyses, we tested six of these motifs and found that they are all functionally important for the activity of AG regulatory sequences in A. thaliana. Although there is little obvious sequence similarity outside the Brassicaceae, the intron from cucumber AG has at least partial activity in A. thaliana. Our studies underscore the value of the comparative approach as a tool that complements gene-by-gene promoter dissection but also demonstrate that sequence-based studies alone are insufficient for a complete identification of cis-regulatory sites. PMID:12782724

  2. Regulatory elements of the floral homeotic gene AGAMOUS identified by phylogenetic footprinting and shadowing.

    SciTech Connect

    Hong, R. L., Hamaguchi, L., Busch, M. A., and Weigel, D.

    2003-06-01

    OAK-B135 In Arabidopsis thaliana, cis-regulatory sequences of the floral homeotic gene AGAMOUS (AG) are located in the second intron. This 3 kb intron contains binding sites for two direct activators of AG, LEAFY (LFY) and WUSCHEL (WUS), along with other putative regulatory elements. We have used phylogenetic footprinting and the related technique of phylogenetic shadowing to identify putative cis-regulatory elements in this intron. Among 29 Brassicaceae, several other motifs, but not the LFY and WUS binding sites previously identified, are largely invariant. Using reporter gene analyses, we tested six of these motifs and found that they are all functionally important for activity of AG regulatory sequences in A. thaliana. Although there is little obvious sequence similarity outside the Brassicaceae, the intron from cucumber AG has at least partial activity in A. thaliana. Our studies underscore the value of the comparative approach as a tool that complements gene-by-gene promoter dissection, but also highlight that sequence-based studies alone are insufficient for a complete identification of cis-regulatory sites.

  3. Study on Shadow Effects of Various Features on Close Range Thermal Images

    NASA Astrophysics Data System (ADS)

    Liao, C. L.; Huang, H. H.

    2012-07-01

    Thermal infrared data become more popular in remote sensing investigation, for it could be acquired both in day and night. The change of temperature has special characteristic in natural environment, so the thermal infrared images could be used in monitoring volcanic landform, the urban development, and disaster prevention. Heat shadow is formed by reflecting radiating capacity which followed the objects. Because of poor spatial resolution of thermal infrared images in satellite sensor, shadow effects were usually ignored. This research focus on discussing the shadow effects of various features, which include metals and nonmetallic materials. An area-based thermal sensor, FLIR-T360 was selected to acquire thermal images. Various features with different emissivity were chosen as reflective surface to obtain thermal shadow in normal atmospheric temperature. Experiments found that the shadow effects depend on the distance between sensors and features, depression angle, object temperature and emissivity of reflective surface. The causes of shadow effects have been altered in the experiment for analyzing the variance in thermal infrared images. The result shows that there were quite different impacts by shadow effects between metals and nonmetallic materials. The further research would be produced a math model to describe the shadow effects of different features in the future work.

  4. A Study on Building an Efficient Job Shadowing Management Methodology for the Undergraduate Students

    ERIC Educational Resources Information Center

    Sakoda, Koichi; Takahashi, Masakazu

    2014-01-01

    This paper describes heuristic knowledge through the job-shadowing project at the International University of Kagoshima, Japan. Job shadowing is one of the conventional in-house trainings given to the executive trainee cadets in North America and proved the effect of training in Leonard's paper for the conventional target such as the executive…

  5. Reply to Comment on Shadow model for sub-barrier fusion applied to light systems' ''

    SciTech Connect

    Scalia, A. )

    1994-05-01

    This is a reply to the Comment on Shadow model for sub-barrier fusion applied to light systems.' '' We confirm the results of our paper. The claimed demonstration of the disagreement between the cross section derived from the shadow'' model and the low energy laboratory data is meaningless because it is based on a comparison which is incorrect.

  6. Observing the shadow of Einstein-Maxwell-Dilaton-Axion black hole

    SciTech Connect

    Wei, Shao-Wen; Liu, Yu-Xiao E-mail: liuyx@lzu.edu.cn

    2013-11-01

    In this paper, the shadows cast by Einstein-Maxwell-Dilaton-Axion black hole and naked singularity are studied. The shadow of a rotating black hole is found to be a dark zone covered by a deformed circle. For a fixed value of the spin a, the size of the shadow decreases with the dilaton parameter b. The distortion of the shadow monotonically increases with b and takes its maximal when the black hole approaches to the extremal case. Due to the optical properties, the area of the black hole shadow is supposed to equal to the high-energy absorption cross section. Based on this assumption, the energy emission rate is investigated. For a naked singularity, the shadow has a dark arc and a dark spot or straight, and the corresponding observables are obtained. These results show that there is a significant effect of the spin a and dilaton parameter b on these shadows. Moreover, we examine the observables of the shadow cast by the supermassive black hole at the center of the Milky Way, which is very useful for us to probe the nature of the black hole through the astronomical observations in the near future.

  7. A Historical Approach to the Teaching of the Linear Propagation of Light, Shadows and Pinhole Cameras

    ERIC Educational Resources Information Center

    Mihas, Pavlos; Andreadis, Panagiotis

    2005-01-01

    In this paper are presented the views of Al Haytham and his predecessors on the shadows, the rectilinear propagation of rays and the images produced by pinholes. Al Haytham had given erroneous views on the distribution of light in the shadows. Educational applications of these are presented. These applications concern: (a) Simple experiments (b)…

  8. Shedding New Light on an Old Problem: The Estimation of Shadow Sizes in Children and Adults

    ERIC Educational Resources Information Center

    Ebersbach, Mirjam; Resing, Wilma C. M.

    2007-01-01

    Two experiments using the "projection of shadows" paradigm investigated multidimensional reasoning, implicit and explicit knowledge, and the nonlinearity concept in 5-, 9-, and 13-year-olds and adults. Participants estimated the resulting shadow lengths of differently sized objects, placed at varying distances from a light source. Experiment 1…

  9. Shadow Education, American Style: Test Preparation, the SAT and College Enrollment

    ERIC Educational Resources Information Center

    Buchmann, Claudia; Condron, Dennis J.; Roscigno, Vincent J.

    2010-01-01

    Cross-national research finds that "shadow education"--educational activities outside of formal schooling--tends to confer advantages on already privileged students. Shadow education in the United States, such as test prep for college entrance exams, has received considerably less attention. Drawing on the National Education Longitudinal Study, we…

  10. Measurement Issues in Research on Shadow Education: Challenges and Pitfalls Encountered in TIMSS and PISA

    ERIC Educational Resources Information Center

    Bray, Mark; Kobakhidze, Magda Nutsa

    2014-01-01

    Expanding numbers of researchers are focusing on the scale and impact of private supplementary tutoring. Such tutoring is widely called shadow education, since much of its curriculum mimics that of regular schooling. Although shadow education has expanded significantly worldwide and is now recognized to have far-reaching significance, research…

  11. School Socioeconomic Compositional Effect on Shadow Education Participation: Evidence from Japan

    ERIC Educational Resources Information Center

    Matsuoka, Ryoji

    2015-01-01

    While shadow education, organized learning activities outside formal school, has grown greatly around the world, the relationship between formal schooling and shadow education has not been well investigated. This study is therefore intended to empirically test whether formal education's structure (i.e. tracking) affects students' shadow…

  12. Gauge invariant approach to low-spin anomalous conformal currents and shadow fields

    SciTech Connect

    Metsaev, R. R.

    2011-05-15

    Conformal low-spin anomalous currents and shadow fields in flat space-time of dimensions greater than or equal to four are studied. The gauge invariant formulation for such currents and shadow fields is developed. Gauge symmetries are realized by involving Stueckelberg and auxiliary fields. The gauge invariant differential constraints for anomalous currents and shadow fields and the realization of global conformal symmetries are obtained. Gauge invariant two-point vertices for anomalous shadow fields are also obtained. In the Stueckelberg gauge frame, these gauge invariant vertices become the standard two-point vertices of conformal field theory. Light-cone gauge two-point vertices of the anomalous shadow fields are derived. The AdS/CFT correspondence for anomalous currents and shadow fields and the respective normalizable and non-normalizable solutions of massive low-spin anti-de Sitter fields is studied. The bulk fields are considered in a modified de Donder gauge that leads to decoupled equations of motion. We demonstrate that leftover on-shell gauge symmetries of bulk massive fields correspond to gauge symmetries of boundary anomalous currents and shadow fields, while the modified (Lorentz) de Donder gauge conditions for bulk massive fields correspond to differential constraints for boundary anomalous currents and shadow fields.

  13. The Link between Speech Perception and Production Is Phonological and Abstract: Evidence from the Shadowing Task

    ERIC Educational Resources Information Center

    Mitterer, Holger; Ernestus, Mirjam

    2008-01-01

    This study reports a shadowing experiment, in which one has to repeat a speech stimulus as fast as possible. We tested claims about a direct link between perception and production based on speech gestures, and obtained two types of counterevidence. First, shadowing is not slowed down by a gestural mismatch between stimulus and response. Second,…

  14. Shadows remain segmented as selectable regions in object-based attention paradigms

    PubMed Central

    de-Wit, Lee; Milner, David; Kentridge, Robert

    2012-01-01

    It is unclear how shadows are processed in the visual system. Whilst shadows are clearly used as an important cue to localise the objects that cast them, there is mixed evidence regarding the extent to which shadows influence the recognition of those objects. Furthermore experiments exploring the perception of shadows per se have provided evidence that the visual system has less efficient access to the detailed form of a region if it is interpreted as a shadow. The current study sought to clarify our understanding of the manner in which shadows are represented by the visual system by exploring how they influence attention in two different object-based attention paradigms. The results provide evidence that cues to interpret a region as a shadow do not reduce the extent to which that region will result in a within-‘object’ processing advantage. Thus, whilst there is evidence that shadows are processed differently at higher stages of object perception, the present result shows that they are still represented as distinctly segmented regions as far as the allocation of attention is concerned. This result is consistent with the idea that object-based attention phenomena result from region-based scene segmentation rather than from the representations of objects per se. PMID:23145275

  15. Art Therapy and Its Shadow: A Jungian Perspective on Professional Identity and Community.

    ERIC Educational Resources Information Center

    Bouchard, Rene R.

    1998-01-01

    Through the lens of Jungian theory of the shadow, this article identifies ways in which its dynamics and manifestations occur in the field of art therapy. Introduces experiential exercises for discovering and working with the shadow and concludes with recommendations for transforming negative dynamics into creative solutions. (Author/MKA)

  16. The Shadow: Mining Its Dark Treasury for Teaching and Adult Development

    ERIC Educational Resources Information Center

    Karpiak, Irene E.

    2003-01-01

    This paper explores the psychological shadow--the disowned self--as one of the hidden, unconscious elements in adult and continuing education, often underlying those inexplicable emotional reactions that transpire in instructor/learner interactions. Drawing on the literature related to the psychological shadow, teaching/learning, and adult…

  17. Discursive Shadowing in Linguistic Ethnography. Situated Practices and Circulating Discourses in Multilingual Schools

    ERIC Educational Resources Information Center

    Dewilde, Joke; Creese, Angela

    2016-01-01

    We consider discursive shadowing as methodology in linguistic ethnography and how it refines our analyses of participants' situated practices. In addition to the constant and extended company the researcher and key participant keep with one another in the field, shadowing in a linguistic ethnographic approach includes the ubiquitous…

  18. Probe of the solar magnetic field using the "cosmic-ray shadow" of the sun.

    PubMed

    Amenomori, M; Bi, X J; Chen, D; Chen, T L; Chen, W Y; Cui, S W; Danzengluobu; Ding, L K; Feng, C F; Feng, Zhaoyang; Feng, Z Y; Gou, Q B; Guo, Y Q; Hakamada, K; He, H H; He, Z T; Hibino, K; Hotta, N; Hu, Haibing; Hu, H B; Huang, J; Jia, H Y; Jiang, L; Kajino, F; Kasahara, K; Katayose, Y; Kato, C; Kawata, K; Labaciren; Le, G M; Li, A F; Li, H J; Li, W J; Liu, C; Liu, J S; Liu, M Y; Lu, H; Meng, X R; Mizutani, K; Munakata, K; Nanjo, H; Nishizawa, M; Ohnishi, M; Ohta, I; Onuma, H; Ozawa, S; Qian, X L; Qu, X B; Saito, T; Saito, T Y; Sakata, M; Sako, T K; Shao, J; Shibata, M; Shiomi, A; Shirai, T; Sugimoto, H; Takita, M; Tan, Y H; Tateyama, N; Torii, S; Tsuchiya, H; Udo, S; Wang, H; Wu, H R; Xue, L; Yamamoto, Y; Yang, Z; Yasue, S; Yuan, A F; Yuda, T; Zhai, L M; Zhang, H M; Zhang, J L; Zhang, X Y; Zhang, Y; Zhang, Yi; Zhang, Ying; Zhaxisangzhu; Zhou, X X

    2013-07-01

    We report on a clear solar-cycle variation of the Sun’s shadow in the 10 TeV cosmic-ray flux observed by the Tibet air shower array during a full solar cycle from 1996 to 2009. In order to clarify the physical implications of the observed solar cycle variation, we develop numerical simulations of the Sun’s shadow, using the potential field source surface model and the current sheet source surface (CSSS) model for the coronal magnetic field. We find that the intensity deficit in the simulated Sun’s shadow is very sensitive to the coronal magnetic field structure, and the observed variation of the Sun’s shadow is better reproduced by the CSSS model. This is the first successful attempt to evaluate the coronal magnetic field models by using the Sun’s shadow observed in the TeV cosmic-ray flux. PMID:24027782

  19. Investigation of semiconductor nanowires with shadow-evaporated epitaxial superconducting shells

    NASA Astrophysics Data System (ADS)

    Watson, John; Cassidy, Maja; Kammhuber, Jakob; de Moor, Michiel; Kouwenhoven, Leo; Krogstrup, Peter; Deng, Mingtang; Jespersen, Thomas; Nygard, Jesper; Marcus, Charles

    We report progress on epitaxially grown InAs/Al core/shell nanowire heterostructures by molecular beam epitaxy with junctions in the Al shells formed in-situ by a crossed wire shadowing method during growth. Such wires allow the creation of superconductor-normal-superconductor (SNS) junctions with high quality superconductor-semiconductor interfaces without introducing damage in the junction by etching the Al. Shadowing is accomplished by a two-step growth process in which the nanowire growth direction is changed resulting in crossed networks of nanowires which shadow one another from the Al flux. We observe hard superconducting gaps and supercurrents in excess of 50 nA with in-plane critical fields above 1 T. We compare our results with shadowed devices to previous data from SNS junctions with wet-etched shells. Our experiments indicate that this crossed wire shadowing technique provides an interesting route to investigating induced superconductivity in semiconductor nanowires.

  20. Uniformity Masks Design Method Based on the Shadow Matrix for Coating Materials with Different Condensation Characteristics

    PubMed Central

    2013-01-01

    An intuitionistic method is proposed to design shadow masks to achieve thickness profile control for evaporation coating processes. The proposed method is based on the concept of the shadow matrix, which is a matrix that contains coefficients that build quantitive relations between shape parameters of masks and shadow quantities of substrate directly. By using the shadow matrix, shape parameters of shadow masks could be derived simply by solving a matrix equation. Verification experiments were performed on a special case where coating materials have different condensation characteristics. By using the designed mask pair with complementary shapes, thickness uniformities of better than 98% are demonstrated for MgF2 (m = 1) and LaF3 (m = 0.5) simultaneously on a 280 mm diameter spherical substrate with the radius curvature of 200 mm. PMID:24227996

  1. A detection method of ground glass opacities in chest x-ray CT images using automatic clustering techniques

    NASA Astrophysics Data System (ADS)

    Tanino, Mitsuhiro; Takizawa, Hotaka; Yamamoto, Shinji; Matsumoto, Tohru; Tateno, Yukio; Iinuma, Takeshi

    2003-05-01

    In this paper, we described an algorithm of automatic detection of Ground Glass Opacities (GGO) from X-ray CT images. In this algorithm, first, suspicious shadows are extracted by our Variable N-Quoit (VNQ) filter which is a type of Mathematical Morphology filters. This filter can detect abnormal shadows with high sensitivity. Next, the suspicious shadows are classified into a certain number of classes using feature values calculated from the suspicious shadows. In our traditional clustering method, a medical doctor has to manually classify the suspicious shadows into 5 clusters. The manual classification is very hard for the doctor. Thus, in this paper, we propose a new automatic clustering method which is based on a Principal Component (PC) theory. In this method, first, the detected shadows are classified into two sub-clusters according to their sizes. And then, each sub-cluster is further classified into two sub-sub-clusters according to PC Scores(PCS) calcuated from the feature values of the shadows in the sub-cluster. In this PCS-based classification, we use a threshold which maximizes the distance between the two sub-sub-clusters. The PCS-based classification is iterated recursively. Using discriminate functions based on Mahalanobis distance, the suspicious shadows are determined to be normal or abnormal. This method was examined by many samples (including GGO's shadows) of chest CT images, and proved to be very effective.

  2. Load-cell based characterization system for a "Violin-Mode" shadow-sensor in advanced LIGO suspensions.

    PubMed

    Lockerbie, N A; Tokmakov, K V

    2016-07-01

    The background to this work was a prototype shadow sensor, which was designed for retro-fitting to an advanced LIGO (Laser Interferometer Gravitational wave Observatory) test-mass/mirror suspension, in which 40 kg test-mass/mirrors are each suspended by four approximately 600 mm long by 0.4 mm diameter fused-silica suspension fibres. The shadow sensor comprised a LED source of Near InfraRed (NIR) radiation and a rectangular silicon photodiode detector, which, together, were to bracket the fibre under test. The aim was to detect transverse Violin-Mode resonances in the suspension fibres. Part of the testing procedure involved tensioning a silica fibre sample and translating it transversely through the illuminating NIR beam, so as to measure the DC responsivity of the detection system to fibre displacement. However, an equally important part of the procedure, reported here, was to keep the fibre under test stationary within the beam, whilst trying to detect low-level AC Violin-Mode resonances excited on the fibre, in order to confirm the primary function of the sensor. Therefore, a tensioning system, incorporating a load-cell readout, was built into the test fibre's holder. The fibre then was excited by a signal generator, audio power amplifier, and distant loudspeaker, and clear resonances were detected. A theory for the expected fundamental resonant frequency as a function of fibre tension was developed and is reported here, and this theory was found to match closely with the detected resonant frequencies as they varied with tension. Consequently, the resonances seen were identified as being proper Violin-Mode fundamental resonances of the fibre, and the operation of the Violin-Mode detection system was validated. PMID:27475586

  3. Load-cell based characterization system for a "Violin-Mode" shadow-sensor in advanced LIGO suspensions

    NASA Astrophysics Data System (ADS)

    Lockerbie, N. A.; Tokmakov, K. V.

    2016-07-01

    The background to this work was a prototype shadow sensor, which was designed for retro-fitting to an advanced LIGO (Laser Interferometer Gravitational wave Observatory) test-mass/mirror suspension, in which 40 kg test-mass/mirrors are each suspended by four approximately 600 mm long by 0.4 mm diameter fused-silica suspension fibres. The shadow sensor comprised a LED source of Near InfraRed (NIR) radiation and a rectangular silicon photodiode detector, which, together, were to bracket the fibre under test. The aim was to detect transverse Violin-Mode resonances in the suspension fibres. Part of the testing procedure involved tensioning a silica fibre sample and translating it transversely through the illuminating NIR beam, so as to measure the DC responsivity of the detection system to fibre displacement. However, an equally important part of the procedure, reported here, was to keep the fibre under test stationary within the beam, whilst trying to detect low-level AC Violin-Mode resonances excited on the fibre, in order to confirm the primary function of the sensor. Therefore, a tensioning system, incorporating a load-cell readout, was built into the test fibre's holder. The fibre then was excited by a signal generator, audio power amplifier, and distant loudspeaker, and clear resonances were detected. A theory for the expected fundamental resonant frequency as a function of fibre tension was developed and is reported here, and this theory was found to match closely with the detected resonant frequencies as they varied with tension. Consequently, the resonances seen were identified as being proper Violin-Mode fundamental resonances of the fibre, and the operation of the Violin-Mode detection system was validated.

  4. Galileo in-situ dust measurements and the sculpting of Jupiter's gossamer rings by its shadow

    NASA Astrophysics Data System (ADS)

    Krüger, Harald; Hamilton, Douglas P.; Moissl, Richard; Grün, Eberhard

    2008-09-01

    Galileo was the first articfiial satellite to orbit Jupiter. During its late orbital mission the spacecraft made two passages through the giant planet's gossamer ring system. The highly sensitive impact-ionization dust detector on board successfully recorded dust impacts during both ring passages and provided the first in-situ measurements from a dusty planetary ring. During the first passage { on 5 November 2002 while Galileo was approaching Jupiter - dust measurements were collected until a spacecraft anomaly at 2:33RJ (Jupiter radii) just 16 min after a close flyby of Amalthea put the spacecraft into a safing mode. The second ring passage on 21 September 2003 provided ring dust measurements down to about 2:5RJ and the Galileo spacecraft was destroyed shortly thereafter in a planned impact with Jupiter. In all, a few thousand dust impacts were counted with the instrument accumulators during both ring passages, but only a total of 110 complete data sets of dust impacts were transmitted to Earth (Krüger et al, Icarus, submitted). Detected particle sizes range from about 0.2 to 5 μm, extending the known size distribution by an order of magnitude towards smaller particles than previously derived from optical imaging (Showalter et al., Icarus 2008). The grain size distribution increases towards smaller particles and shows an excess of these tiny motes in the Amalthea gossamer ring compared to the Thebe ring. The size distribution for the Amalthea ring derived from our in-situ measurements for the small grains agrees very well with the one obtained from images for large grains. Our analysis shows that particles contributing most to the optical cross-section are approximately 5 μm in radius, in agreement with imaging results. The measurements indicate a large drop in particle ux immediately interior to Thebe's orbit and some detected particles seem to be on highly-tilted orbits with inclinations up to 20°. Finally, the faint Thebe ring extension was detected out to

  5. Perception of the Motion Trajectory of Objects from Moving Cast Shadows in Infant Japanese Macaques ("Macaca fuscata")

    ERIC Educational Resources Information Center

    Imura, Tomoko; Adachi, Ikuma; Hattori, Yuko; Tomonaga, Masaki

    2013-01-01

    The shadows cast by moving objects enable human adults and infants to infer the motion trajectories of objects. Nonhuman animals must also be able to discriminate between objects and their shadows and infer the spatial layout of objects from cast shadows. However, the evolutionary and comparative developmental origins of sensitivity to cast…

  6. Experiences of teens living in the shadow of Huntington Disease

    PubMed Central

    Sparbel, Kathleen J. H.; Driessnack, Martha; Williams, Janet K.; Schutte, Debra L.; Tripp-Reimer, Toni; McGonigal-Kenney, Meghan; Jarmon, Lori; Paulsen, Jane S.

    2010-01-01

    Research on families with Huntington Disease (HD) has primarily focused on adult decision-making surrounding predictive genetic testing and caregiver stress. Little is known about the experiences of teens living in these families. This qualitative study explored the experiences of 32 teens living in families with HD. Six focus groups were conducted across the U.S. and Canada. Data were analyzed using descriptive qualitative analysis. HD appeared to cast a shadow over the experiences described by teens. Four themes were identified: Watching and waiting; Alone in the midst of others; Family life is kind of hard; and Having to be like an adult. These experiences highlight the need for genetic counselors, health care providers, and school personnel to be aware of issues facing teens living in families with HD. Recognizing patterns of teen experiences may help health care providers develop strategies to support coping by teens in HD families. PMID:18347962

  7. The shadow of inequitable conduct in the US patent application.

    PubMed

    Chang, Bao-Chi; Wang, Shyh-Jen

    2016-05-01

    Inequitable conduct regarding any single claim can render the entire patent unenforceable and further damage other related patents and applications in the assignee's patent portfolio. The adverse impact of inequitable conduct significantly became a litigation strategy. The US Federal Circuit (CAFC) observed that inequitable conduct as a patent litigation strategy had become a plague and thus tightened the standard for finding inequitable conduct in a case with full court judges. However, under the shadow of previous adverse impact of inequitable conduct, patent applicants may still submit many marginal related references. This study demonstrates that an applicant even prepared an information disclosure statement (IDS) as many as 50 pages. Actually, under the new standard, inequitable conduct would not further produce significant impact in the US patent system. Thus, a patent applicant need not submit marginal references but should distinguish the prior art from the current application, especially for those listed in the IDS, to avoid the novelty rejection. PMID:26810884

  8. Light-matter interaction induces a shadow vortex

    NASA Astrophysics Data System (ADS)

    Barboza, R.; Bortolozzo, U.; Clerc, M. G.; Davila, J. D.; Kowalczyk, M.; Residori, S.; Vidal-Henriquez, E.

    2016-05-01

    By sending a light beam on a homeotropic nematic liquid-crystal cell subjected to a voltage with a photosensitive wall, a stable matter vortex can be induced at the center of the beam. When the applied voltage is decreased, the vortex disappears from the illuminated region; however, the system shows a stationary molecular texture. Based on a forced Ginzburg-Landau amplitude equation, we show that the vortex with a core of exponentially suppressed amplitude always remains in a shadow region below instability threshold and that the observed texture is induced by its phase distribution. This is a different type of vortex phase singularity solution. Numerical simulations and experimental observations show a quite fair agreement.

  9. Least Squares Shadowing sensitivity analysis of chaotic limit cycle oscillations

    NASA Astrophysics Data System (ADS)

    Wang, Qiqi; Hu, Rui; Blonigan, Patrick

    2014-06-01

    The adjoint method, among other sensitivity analysis methods, can fail in chaotic dynamical systems. The result from these methods can be too large, often by orders of magnitude, when the result is the derivative of a long time averaged quantity. This failure is known to be caused by ill-conditioned initial value problems. This paper overcomes this failure by replacing the initial value problem with the well-conditioned "least squares shadowing (LSS) problem". The LSS problem is then linearized in our sensitivity analysis algorithm, which computes a derivative that converges to the derivative of the infinitely long time average. We demonstrate our algorithm in several dynamical systems exhibiting both periodic and chaotic oscillations.

  10. Light-matter interaction induces a shadow vortex.

    PubMed

    Barboza, R; Bortolozzo, U; Clerc, M G; Davila, J D; Kowalczyk, M; Residori, S; Vidal-Henriquez, E

    2016-05-01

    By sending a light beam on a homeotropic nematic liquid-crystal cell subjected to a voltage with a photosensitive wall, a stable matter vortex can be induced at the center of the beam. When the applied voltage is decreased, the vortex disappears from the illuminated region; however, the system shows a stationary molecular texture. Based on a forced Ginzburg-Landau amplitude equation, we show that the vortex with a core of exponentially suppressed amplitude always remains in a shadow region below instability threshold and that the observed texture is induced by its phase distribution. This is a different type of vortex phase singularity solution. Numerical simulations and experimental observations show a quite fair agreement. PMID:27300814

  11. Charged dust dynamics - Orbital resonance due to planetary shadows

    NASA Technical Reports Server (NTRS)

    Horanyi, M.; Burns, J. A.

    1991-01-01

    The dynamics of a weakly charged dust grain orbiting in the equatorial plane of a planet surrounded by a rigidly corotating magnetospehre is examined. It is shown that an introduction of an effectilve 1D potential causes a perturbation due to electrostatic forces, which induces a motion of the pericenter, similar to the effect of the planetary oblateness. A case is examined where the charge varies periodically due to the modulation of the photoelectron current occurring as the grain enters and leaves the planetary shadow, causing the electromagnetic perturbation to resonate with the orbital period and to modify the size and eccentricity of the orbit. This effect is demonstrated both numerically and analytically for small grains comprising the Jovian ring, showing that their resulting changes are periodic, and their amplitude is much larger than that of the periodic changes due to light-pressure perturbation or the secular changes due to resonant charge variations that develop over a comparable time span.

  12. Point symmetry in x-ray shadow imaging systems

    SciTech Connect

    Aristov, V.V.; Shabel'nikov, L.G.

    1988-04-01

    General geometrical features have been examined to identify point-group symmetries in x-ray imaging systems. In a stereospecific system, the group is the b/w antisymmetry group 2/m'. In a computerized tomography system, the symmetry is described by the limiting Curie group /infinity//m/center dot/m, while for a tomosynthesis system (transaxial tomography), it is /infinity//m. The operations in these groups have been examined in the production of shadow images involving distributed attenuation coefficients, particularly for stereospecific images recorded with an MIR-3 x-ray microscope. Curie's principle is used to show that reconstructed paired images for two intersecting objects can be considered as the equivalent of stereoscopic pairs for computer-aided tomography, which is not so for transaxial tomography.

  13. Optical properties of silver/gold nanostructures fabricated by shadowing growth and their sensing applications

    NASA Astrophysics Data System (ADS)

    Fu, Junxue; Zhao, Yiping

    2010-08-01

    Various Ag and Au nanostructured films such as Ag nanoparticle (NP) films, Au NP films, and Au NP/TiO2/Au NP sandwich structures are fabricated by oblique angle deposition (OAD) and glancing angle deposition (GLAD) methods. Their optical absorbance properties and localized surface plasmon resonance (LSPR) have been studied systematically for samples prepared at different deposition conditions. Under the same deposition conditions, the Ag or Au NP substrates produced by GLAD method are more uniform and reproducible. The LSPR wavelength of Ag or Au NP substrates can be easily tuned by changing the film thickness, the deposition angle, and the coating of dielectric layer. The ability of the nanoparticle films as a chemical and biological biosensor has been explored by sensing the biomolecule NeutrAvidin and the bacterium Salmonella. Those NP films are very sensitive to chemical detection but are insensitive for bacteria detection. Based on Mie theory and effective medium theory, this is due to the small contact area between the nanoparticle and the bacteria, and the short range interaction of the local electric field. Our results demonstrate that shadowing based growth is a very versatile fabrication technique to produce reproducible and finetuned LSPR substrates.

  14. Method for the calculation of spacecraft umbra and penumbra shadow terminator points

    NASA Technical Reports Server (NTRS)

    Ortizlongo, Carlos R.; Rickman, Steven L.

    1995-01-01

    A method for calculating orbital shadow terminator points is presented. The current method employs the use of an iterative process which is used for an accurate determination of shadow points. This calculation methodology is required since orbital perturbation effects can introduce large errors when a spacecraft orbits a planet in a high altitude and/or highly elliptical orbit. To compensate for the required iteration methodology, all reference frame change definitions and calculations are performed with quaternions. Quaternion algebra significantly reduces the computational time required for the accurate determination of shadow terminator points.

  15. Cold Nuclear Matter effects on J/psi production at RHIC: comparing shadowing models

    SciTech Connect

    Ferreiro, E.G.; Fleuret, F.; Lansberg, J.P.; Rakotozafindrabe, A.; /SPhN, DAPNIA, Saclay

    2009-06-19

    We present a wide study on the comparison of different shadowing models and their influence on J/{psi} production. We have taken into account the possibility of different partonic processes for the c{bar c}-pair production. We notice that the effect of shadowing corrections on J/{psi} production clearly depends on the partonic process considered. Our results are compared to the available data on dAu collisions at RHIC energies. We try different break up cross section for each of the studied shadowing models.

  16. Drug-induced Hypersensitivity Syndrome Accompanied by Pulmonary Lesions Exhibiting Centrilobular Nodular Shadows.

    PubMed

    Sawata, Tetsuro; Bando, Masashi; Kogawara, Haruna; Nakayama, Masayuki; Mato, Naoko; Yamasawa, Hideaki; Takemura, Tamiko; Sugiyama, Yukihiko

    2016-01-01

    A 51-year-old woman diagnosed with Crohn's disease developed drug-induced hypersensitivity syndrome (DIHS) 12 and six weeks after starting the oral intake of mesalazine and trimethoprim/sulfamethoxazole, respectively. Chest CT showed centrilobular nodular shadows and a transbronchial lung biopsy (TBLB) revealed infiltration of inflammatory cells predominantly in the small pulmonary artery walls and bronchiolar walls. Regarding pulmonary lesions of DIHS, infiltrative shadows have sometimes been reported, whereas nodular shadows have rarely been documented. This is a valuable case report for considering the mechanism underlying the development of pulmonary lesions in case of DIHS. PMID:27150872

  17. An analytical and experimental evaluation of shadow shields and their support members

    NASA Technical Reports Server (NTRS)

    Stochl, R. J.; Boyle, R. J.

    1972-01-01

    Experimental tests were performed on a model shadow shield thermal protection system to examine the effect of certain configuration variables. The experimental results were used to verify the ability of an analytical program to predict the shadow shield performance including the shield-support interaction. In general, the analysis (assuming diffuse surfaces) agreed well with the experimental support temperature profiles. The agreement for the shield profiles was not as good. The results demonstrated: (1) shadow shields can be effective in reducing the heat transfer into cryogenic propellant tanks, and (2) the conductive heat transfer through supports can be reduced by selective surface coatings.

  18. A generalised formulation of beam-shadow measurement in spiral-sector superconducting cyclotron

    NASA Astrophysics Data System (ADS)

    Pradhan, Jedidiah; Dey, Malay Kanti; Chakrabarti, Alok

    2014-06-01

    A generalised analysis of coherent radial oscillation through shadow measurements on the beam in a spiral-sector, superconducting cyclotron is discussed here. Experimental measurements of shadow cast by one beam-probe on another have been used to study beam behaviour at different radial positions of the K500 superconducting cyclotron at this institute. The correlation of radial oscillation and shadow measurements as well as the motion of orbit centre are also described. The modulation of turn separation by coherent radial oscillation is used to estimate the oscillation amplitude and dee voltage.

  19. Physics of Partially Ionized Plasmas

    NASA Astrophysics Data System (ADS)

    Krishan, Vinod

    2016-05-01

    Figures; Preface; 1. Partially ionized plasmas here and everywhere; 2. Multifluid description of partially ionized plasmas; 3. Equilibrium of partially ionized plasmas; 4. Waves in partially ionized plasmas; 5. Advanced topics in partially ionized plasmas; 6. Research problems in partially ionized plasmas; Supplementary matter; Index.

  20. Determination of the partial benzodiazepine receptor agonist Ro 16-6028 in plasma by capillary gas chromatography with nitrogen-selective detection after conversion into the ethyl ester derivative.

    PubMed

    Timm, U; Fischer, G; Zell, M; Zumbrunnen, R

    1989-09-29

    A highly sensitive capillary gas chromatographic method was developed to determine plasma levels of a novel partial benzodiazepine receptor agonist in man following the very low therapeutic doses required for anxiolysis. The compound was isolated from plasma by liquid-liquid extraction at basic pH, converted into the ethyl ester analogue by a two-step procedure, separated from plasma constituents by capillary gas chromatography and quantified by means of nitrogen-selective detection. Because of the thermolabile tert.-butyl ester function, the agonist could not be gas chromatographed without degradation. Formation of the far more stable ethyl ester analogue was achieved by treatment with hydrogen chloride in ethanol, followed by an ethylation step with diazoethane. The high sensitivity of the new method (about 100 pg/ml, using 1-ml plasma specimens) allowed the monitoring of plasma levels of the agonist for up to 8 h (about three elimination half-lives) after a single 0.1-mg oral dose to human volunteers. The practicability of the procedure was demonstrated by the analysis of more than 600 plasma samples from clinical studies performed with human volunteers. PMID:2573608

  1. Detection of Multiple Budding Yeast Cells and a Partial Sequence of 43-kDa Glycoprotein Coding Gene of Paracoccidioides brasiliensis from a Case of Lacaziosis in a Female Pacific White-Sided Dolphin (Lagenorhynchus obliquidens).

    PubMed

    Minakawa, Tomoko; Ueda, Keiichi; Tanaka, Miyuu; Tanaka, Natsuki; Kuwamura, Mitsuru; Izawa, Takeshi; Konno, Toshihiro; Yamate, Jyoji; Itano, Eiko Nakagawa; Sano, Ayako; Wada, Shinpei

    2016-08-01

    Lacaziosis, formerly called as lobomycosis, is a zoonotic mycosis, caused by Lacazia loboi, found in humans and dolphins, and is endemic in the countries on the Atlantic Ocean, Indian Ocean and Pacific Ocean of Japanese coast. Susceptible Cetacean species include the bottlenose dolphin (Tursiops truncatus), the Indian Ocean bottlenose dolphin (T. aduncus), and the estuarine dolphin (Sotalia guianensis); however, no cases have been recorded in other Cetacean species. We diagnosed a case of Lacaziosis in a Pacific white-sided dolphin (Lagenorhynchus obliquidens) nursing in an aquarium in Japan. The dolphin was a female estimated to be more than 14 years old at the end of June 2015 and was captured in a coast of Japan Sea in 2001. Multiple, lobose, and solid granulomatous lesions with or without ulcers appeared on her jaw, back, flipper and fluke skin, in July 2014. The granulomatous skin lesions from the present case were similar to those of our previous cases. Multiple budding and chains of round yeast cells were detected in the biopsied samples. The partial sequence of 43-kDa glycoprotein coding gene confirmed by a nested PCR and sequencing, which revealed a different genotype from both Amazonian and Japanese lacaziosis in bottlenose dolphins, and was 99 % identical to those derived from Paracoccidioides brasiliensis; a sister fungal species to L. loboi. This is the first case of lacaziosis in Pacific white-sided dolphin. PMID:26883513

  2. Fully constrained linear spectral unmixing based global shadow compensation for high resolution satellite imagery of urban areas

    NASA Astrophysics Data System (ADS)

    Yang, Jian; He, Yuhong; Caspersen, John

    2015-06-01

    Shadows commonly exist in high resolution satellite imagery, particularly in urban areas, which is a combined effect of low sun elevation, off-nadir viewing angle, and high-rise buildings. The presence of shadows can negatively affect image processing, including land cover classification, mapping, and object recognition due to the reduction or even total loss of spectral information in shadows. The compensation of spectral information in shadows is thus one of the most important preprocessing steps for the interpretation and exploitation of high resolution satellite imagery in urban areas. In this study, we propose a new approach for global shadow compensation through the utilization of fully constrained linear spectral unmixing. The basic assumption of the proposed method is that the construction of the spectral scatter plot in shadows is analogues to that in non-shadow areas within a two-dimension spectral mixing space. In order to ensure the continuity of land covers, a smooth operator is further used to refine the restored shadow pixels on the edge of non-shadow and shadow areas. The proposed method is validated using the WorldView-2 multispectral imagery collected from downtown Toronto, Ontario, Canada. In comparison with the existing linear-correlation correction method, the proposed method produced the compensated shadows with higher quality.

  3. Waiting for Shadows from the Distant Solar System

    NASA Astrophysics Data System (ADS)

    Kohler, Susanna

    2016-03-01

    How can we hope to measure the hundreds of thousands of objects in our distant solar system? A team of astronomers is harnessing citizen science to begin to tackle this problem!A light curve from an occultation collected by a RECON site in Quincy, California. As the objects shadow passes, the background stars light dims. [RECON/Charley Arrowsmith (Feather River College)]Occultation InformationEstimates currently place the number of Kuiper belt objects larger than 100 km across at over 100,000. Knowing the sizes and characteristics of these objects is important for understanding the composition of the outer solar system and constraining models of the solar systems formation and evolution.Unfortunately, measuring small, dim bodies at large distances is incredibly difficult! One of the best ways to obtain the sizes of these objects is to watch as they occult a distant star. Timing the object as it passes across the face of the star can give us a good measure of its size and shape, when observed from multiple stations in the path of the shadow.An Extended NetworkOccultations by nearby objects (like main-belt asteroids) can be predicted fairly accurately, but those by trans-Neptunian objects are much more poorly constrained. Only ~900 trans-Neptunian objects have approximately known paths, and occultation-shadow predictions for these objects are often only accurate to ~1000km on the Earths surface. So how can we ensure that theres a telescope in the right location, ready to observe when an occultation occurs?Map of the 56 RECON sites distributed over 2000 km in the western United States. [Buie et al. 2016]The simplest answer is to set up a huge network of observing stations, and wait for the shadows to come to the network. With this approach, even if the predicted path isnt precisely known, some of the stations will still observe the occultation.Due to the number of stations needed, this project lends itself perfectly to citizen science. In a recently published paper by

  4. Casting Light and Shadows on a Saharan Dust Storm

    NASA Technical Reports Server (NTRS)

    2003-01-01

    On March 2, 2003, near-surface winds carried a large amount of Saharan dust aloft and transported the material westward over the Atlantic Ocean. These observations from the Multi-angle Imaging SpectroRadiometer (MISR) aboard NASA's Terra satellite depict an area near the Cape Verde Islands (situated about 700 kilometers off of Africa's western coast) and provide images of the dust plume along with measurements of its height and motion. Tracking the three-dimensional extent and motion of air masses containing dust or other types of aerosols provides data that can be used to verify and improve computer simulations of particulate transport over large distances, with application to enhancing our understanding of the effects of such particles on meteorology, ocean biological productivity, and human health.

    MISR images the Earth by measuring the spatial patterns of reflected sunlight. In the upper panel of the still image pair, the observations are displayed as a natural-color snapshot from MISR's vertical-viewing (nadir) camera. High-altitude cirrus clouds cast shadows on the underlying ocean and dust layer, which are visible in shades of blue and tan, respectively. In the lower panel, heights derived from automated stereoscopic processing of MISR's multi-angle imagery show the cirrus clouds (yellow areas) to be situated about 12 kilometers above sea level. The distinctive spatial patterns of these clouds provide the necessary contrast to enable automated feature matching between images acquired at different view angles. For most of the dust layer, which is spatially much more homogeneous, the stereoscopic approach was unable to retrieve elevation data. However, the edges of shadows cast by the cirrus clouds onto the dust (indicated by blue and cyan pixels) provide sufficient spatial contrast for a retrieval of the dust layer's height, and indicate that the top of layer is only about 2.5 kilometers above sea level.

    Motion of the dust and clouds is directly

  5. Near-infrared brightness of the Galilean satellites eclipsed in Jovian shadow: A new technique to investigate Jovian upper atmosphere

    SciTech Connect

    Tsumura, K.; Arimatsu, K.; Matsuura, S.; Shirahata, M.; Wada, T.; Egami, E.; Hayano, Y.; Minowa, Y.; Honda, C.; Kimura, J.; Kuramoto, K.; Takahashi, Y.; Nakajima, K.; Nakamoto, T.; Surace, J.

    2014-07-10

    Based on observations from the Hubble Space Telescope and the Subaru Telescope, we have discovered that Europa, Ganymede, and Callisto are bright around 1.5 μm even when not directly lit by sunlight. The observations were conducted with non-sidereal tracking on Jupiter outside of the field of view to reduce the stray light subtraction uncertainty due to the close proximity of Jupiter. Their eclipsed luminosity was 10{sup –6}-10{sup –7} of their uneclipsed brightness, which is low enough that this phenomenon has been undiscovered until now. In addition, Europa in eclipse was <1/10 of the others at 1.5 μm, a potential clue to the origin of the source of luminosity. Likewise, Ganymede observations were attempted at 3.6 μm by the Spitzer Space Telescope, but it was not detected, suggesting a significant wavelength dependence. It is still unknown why they are luminous even when in the Jovian shadow, but forward-scattered sunlight by hazes in the Jovian upper atmosphere is proposed as the most plausible candidate. If this is the case, observations of these Galilean satellites while eclipsed by the Jovian shadow provide us with a new technique to investigate the Jovian atmospheric composition. Investigating the transmission spectrum of Jupiter by this method is important for investigating the atmosphere of extrasolar giant planets by transit spectroscopy.

  6. Albedo of Permanently Shadowed Regions of the Lunar Poles

    NASA Astrophysics Data System (ADS)

    Riner, M. A.; Lucey, P. G.; Bussey, B.; Cahill, J. T.; McGovern, A.

    2012-12-01

    Due to the slight tilt in the Moon's spin axis, some topographic depressions near the lunar poles experience permanent shadow and may serve as cold traps, harboring water ice and/or other volatile compounds [1]. Permanently shadowed regions (PSRs) provide an opportunity toward understanding the amount, nature and transport of volatiles on the Moon and may also be a potential resource for human exploration. While many different data sets have suggested the presence of water ice in PSRs near the lunar poles many questions remain. For example, ice does not appear to be uniformly distributed across identified PSRs. More work is needed to understand the distribution of ice in PSRs and how delivery and retention mechanisms influence the distribution. The active illumination of the Lunar Orbiter Laser Altimeter (LOLA) provides a unique contribution toward exploration PSR exploration. While LOLA is principally a laser altimeter used for quantitative topography and related cartographic and geodetic applications [2], LOLA also measures the intensity and width of the return laser pulse (1064 nm) from the surface. Here we use a global mosaic (4 pixels per degree) of LOLA albedo data corrected for instrumental drift, irregular variations, and calibrated to normal albedo using local equatorial measurements of normal albedo obtained by the Kaguya Multiband Imager [3]. Recent work using LOLA albedo shows the floor of Shackleton crater, near the lunar south pole, is brighter than the surrounding terrain (and the interior of nearby craters) at 1064 nm [4]. This albedo difference may be due to decreased space weathering due to shadowing from the Sun or to a 1 μm thick layer with 20% water ice a the surface of the crater floor [4]. Here we use LOLA dayside reflectance measurements to examine the albedo of PSRs catalogued by [5] derived from illumination modeling of a hybrid 100 m/pixel LOLA-LROC digital terrain model (DTM) up to 83° north and south latitudes. The upper latitude

  7. Why arthroscopic partial meniscectomy?

    PubMed

    Lyu, Shaw-Ruey

    2015-09-01

    "Arthroscopic Partial Meniscectomy versus Sham Surgery for a Degenerative Meniscal Tear" published in the New England Journal of Medicine on December 26, 2013 draws the conclusion that arthroscopic partial medial meniscectomy provides no significant benefit over sham surgery in patients with a degenerative meniscal tear and no knee osteoarthritis. This result argues against the current practice of performing arthroscopic partial meniscectomy (APM) in patients with a degenerative meniscal tear. Since the number of APM performed has been increasing, the information provided by this study should lead to a change in clinical care of patients with a degenerative meniscus tear. PMID:26488013

  8. Functional relation among subpixel canopy cover, ground shadow, and illuminated ground at large sampling scales

    NASA Technical Reports Server (NTRS)

    Jasinski, Michael F.

    1990-01-01

    The functional relation among subpixel canopy cover, illuminated soil, and shadowed soil, which progressively develops with increasing pixel size, is investigated for Poisson distributed plants using a geometric canopy simulation model. An analytical relation among cover components is shown to be applicable when the scale of the pixel is much larger than the scale of the plant and ground shadow. The analysis is facilitated through the use of a nondimensional solar-geometric similarity parameter, eta, equal to the ratio of the area of one plant canopy to its associated ground shadow area, as viewed from nadir. A sampling scale ratio, defined as the ratio of the area of the pixel to the mean area of a single plant shadow, is tested as a quantitative criterion to evaluate when the functional relation among subpixel components occurs. The results of a remote sensing experiment over a natural conifer landscape provide preliminary confirmation of the theoretical analysis.

  9. Color fluctuation approximation for multiple interactions in leading twist theory of nuclear shadowing

    SciTech Connect

    Vadim Guzey, Mark Strikman

    2010-04-01

    The leading twist theory of nuclear shadowing predicts nuclear parton distributions in the small $x$ shadowing region by connecting them to the leading twist hard diffraction in electron-nucleon scattering. The uncertainties of the predictions are related to the shadowing effects resulting from the interaction of the hard probe with $N \\ge 3$ nucleons. We argue that the pattern of hard diffraction observed at HERA allows one to reduce these uncertainties, and we develop a new approach to the treatment of these multiple collisions. It is based on the concept of the color fluctuations and accounts for the presence of both point-like and hadron-like configurations in the virtual photon. Using the developed framework, we update our predictions for the effect of the leading twist nuclear shadowing in nuclear parton distributions of heavy nuclei at small $x$.

  10. 43. ARAIII Water storage tank ARA709. Camera facing northwest. Shadow ...

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

    43. ARA-III Water storage tank ARA-709. Camera facing northwest. Shadow of ARA-611 at lower right corner of view. Ineel photo no. 3-18. - Idaho National Engineering Laboratory, Army Reactors Experimental Area, Scoville, Butte County, ID

  11. Leading twist nuclear shadowing, nuclear generalized parton distributions and nuclear DVCS at small x

    SciTech Connect

    Guzey, Vadim; Goeke, Klaus; Siddikov, Marat

    2009-01-01

    We generalize the leading twist theory of nuclear shadowing and calculate quark and gluon generalized parton distributions (GPDs) of spinless nuclei. We predict very large nuclear shadowing for nuclear GPDs. In the limit of the purely transverse momentum transfer, our nuclear GPDs become impact parameter dependent nuclear parton distributions (PDFs). Nuclear shadowing induces non-trivial correlations between the impact parameter $b$ and the light-cone fraction $x$. We make predictions for the deeply virtual Compton scattering (DVCS) amplitude and the DVCS cross section on $^{208}$Pb at high energies. We calculate the cross section of the Bethe-Heitler (BH) process and address the issue of the extraction of the DVCS signal from the $e A \\to e \\gamma A$ cross section. We find that the $e A \\to e \\gamma A$ differential cross section is dominated by DVCS at the momentum transfer $t$ near the minima of the nuclear form factor. We also find that nuclear shadowing leads

  12. Shadow Higgs boson from a scale-invariant hidden U(1){sub s} model

    SciTech Connect

    Chang, W.-F.; Ng, John N.; Wu, Jackson M. S.

    2007-06-01

    We study a scale-invariant SU(2)xU(1){sub Y}xU(1){sub s} model which has only dimensionless couplings. The shadow U(1){sub s} is hidden, and it interacts with the standard model (SM) solely through mixing in the scalar sector and kinetic mixing of the U(1) gauge bosons. The gauge symmetries are broken radiatively by the Coleman-Weinberg mechanism. Lifting of the flat direction in the scalar potential gives rise to a light scalar, the scalon, or the shadow Higgs, and a heavier scalar which we identify as the SM Higgs boson. The phenomenology of this model is discussed. In particular, the constraints on the shadow Higgs in different mass ranges, and the possibility of discovering a shadow Higgs with a mass a few tens of GeV in precision t-quark studies at the LHC, are investigated.

  13. The X-ray shadow of the high-latitude molecular cloud MBM 12

    NASA Technical Reports Server (NTRS)

    Snowden, S. L.; Mccammon, D.; Verter, F.

    1993-01-01

    ROSAT XRT/PSPC observations show a deep shadow cast by the high-latitude molecular cloud MBM 12 in the 3/4 keV diffuse background. Modeling of the shadow implies that less than 20 percent of the typical high-latitude 3/4 keV diffuse background intensity is emitted in front of the cloud (D = 60-70 pc). A weaker shadow consistent with the lower optical depth at higher energies was observed in the 1.5 keV band. Since little shadowing was seen in the 1/4 keV band, this observation places strong constraints on the amount of 0.5-2 keV emission that is intermixed with the source of the observed 1/4 keV flux.

  14. Curvature of blended rolled edge reflectors at the shadow boundary contour

    NASA Technical Reports Server (NTRS)

    Ellingson, S. W.

    1988-01-01

    A technique is advanced for computing the radius of curvature of blended rolled edge reflector surfaces at the shadow boundary, in the plane perpendicular to the shadow boundary contour. This curvature must be known in order to compute the spurious endpoint contributions in the physical optics (PO) solution for the scattering from reflectors with rolled edges. The technique is applicable to reflectors with radially-defined rim-shapes and rolled edge terminations. The radius of curvature for several basic reflector systems is computed, and it is shown that this curvature can vary greatly along the shadow boundary contour. Finally, the total PO field in the target zone of a sample compact range system is computed and corrected using the shadow boundary radius of curvature, obtained using the technique. It is shown that the fields obtained are a better approximation to the true scattered fields.

  15. Partial knee replacement - slideshow

    MedlinePlus

    ... page: //medlineplus.gov/ency/presentations/100225.htm Partial knee replacement - series To use the sharing features on ... A.M. Editorial team. Related MedlinePlus Health Topics Knee Replacement A.D.A.M., Inc. is accredited ...

  16. Partial knee replacement

    MedlinePlus

    Most people recover quickly and have much less pain than they did before surgery. People who have a partial knee replacement recover faster than those who have a total knee replacement. Many people are able to walk ...

  17. Twisted partially pure spinors

    NASA Astrophysics Data System (ADS)

    Herrera, Rafael; Tellez, Ivan

    2016-08-01

    Motivated by the relationship between orthogonal complex structures and pure spinors, we define twisted partially pure spinors in order to characterize spinorially subspaces of Euclidean space endowed with a complex structure.

  18. ASCA Observation of an "X-Ray Shadow" in the Galactic Plane

    NASA Technical Reports Server (NTRS)

    Park, Sangwook

    2000-01-01

    The diffuse X-ray background (DXB) emission near the Galactic plane (l,b about 25.6 deg., 0.78 deg.) has been observed with ASC.4. The observed re-ion is toward a Galactic molecular'cloud which was recently reported to cast a deep X-ray shadow in the 0.5 - 2.0 keV band DXB. The selection of this particular region is intended to provide a constraint on the spatial distribution of the DXB emission along the line of sight: i.e., the molecular cloud is optically thick at < 2 keV and so the bulk of the observed soft X-rays must originate in the foreground of the cloud, which is at about 3 kpc from the Sun. In the 0.8 - 9.0 keV band, atomic emission lines have been detected, and the observed spectrum is primarily from thermal plasmas. Although the detailed nature of the spectrum is complicated, the observed DXB emission appears to originate from the multiple components of hot plasmas including a thermal plasma of T about 10(exp 7) K, which prevails within about 3 kpc from the Sun.

  19. ASCA Observation of an "X-Ray Shadow" in the Galactic Plane

    NASA Technical Reports Server (NTRS)

    Park, Sangwook; Ebisawa, Ken

    2001-01-01

    The diffuse X-ray background (DXB) emission near the Galactic plane (l,b approximately 25.6 degrees, 0.78 degrees) has been observed with ASCA (Advanced Satellite for Cosmology and Astrophysics). The observed region is toward a Galactic molecular cloud which was recently reported to cast a deep X-ray shadow in the 0.5 - 2.0 keV band DXB. The selection of this particular region is intended to provide a constraint on the spatial distribution of the DXB emission along the line of sight: i.e., the molecular cloud is optically thick at <2 keV and so the bulk of the observed soft X-rays must originate in the foreground of the cloud, which is at approximately 3 kpc from the Sun. In the 0.8 - 9.0 keV band, the observed spectrum is primarily from multiple components of thermal plasmas. We here report a detection of soft X-ray (0.5 - 2 keV) emission from an approximately 10(exp 7) K thermal plasma. Comparisons with the ROSAT (Roentgen Satellite) data suggest that this soft X-ray emission is absorbed by N(sub H) = 1 - 3 x 10(exp 21) cm(exp -2), which implies a path-length through the soft X-ray emitting regions of approximately less than 1 kpc from the Sun.

  20. A LIKELY MICRO-QUASAR IN THE SHADOW OF M82 X-1

    SciTech Connect

    Xu, Xiao-jie; Liu, Jifeng; Liu, Jiren E-mail: jfliu@nao.cas.cn

    2015-02-01

    The ultra-luminous X-ray source M82 X-1 is one of the most promising intermediate mass black hole candidates in the local universe based on its high X-ray luminosities (10{sup 40}–10{sup 41} erg s{sup −1}) and quasi-periodic oscillations, and is possibly associated with a radio flare source. In this work, applying the sub-pixel technique to the 120 ks Chandra observation (ID: 10543) of M82 X-1, we split M82 X-1 into two sources separated by 1.″1. The secondary source is not detected in other M82 observations. The radio flare source is not found to associate with M82 X-1, but is instead associated with the nearby transient source S1 with an outburst luminosity of ∼10{sup 39} erg s{sup −1}. With X-ray outburst and radio flare activities analogous to the recently discovered micro-quasar in M31, S1 is likely to be a micro-quasar hidden in the shadow of M82 X-1.

  1. [Construction of vegetation shadow index (SVI) and application effects in four remote sensing images].

    PubMed

    Xu, Zhang-Hua; Liu, Jian; Yu, Kun-Yong; Liu, Tao; Gong, Cong-Hong; Tang, Meng-Ya; Xie, Wan-Jun; Li, Zeng-Lu

    2013-12-01

    Taking the images of Landsat TM, ALOS AVNIR-2, CBERS-02B CCD and HJ-1 CCD as the experimental data, for increasing the differences among shaded area, bright area and water further, the present paper construed a novel vegetation index-Shaded Vegetation Index(SVI), which can not only keep the absolute differences among bright area, shaded area and water area in the near-infrared band, but also can enlarge NDVI, eliminate the possible mixes, and change the histogram "skewed" phenomenon of NDVI, so the vegetation index value is closer to normal distribution, and more in line with the filed condition; this new index was applied to the surface features of large difference of the near-infrared radiation characteristics. Verified by accuracy assessment for the bright area, shaded area and water area recognition effects with SVI, it was showed that the overall classification accuracies of these images were up to 98. 89%, 100%, 97.78% and 97.78% respectively, with the overall Kappa statistics of 0.9833, 1, 0.9667, and 0.966 7, indicating that SVI has excellent detection effects for bright area, shaded area and water area; the statistical comparison of sub-images between SVI and NDVI also illustrated the reliability and effectiveness of SVI, which can be applied in the shadow removal for remote sensing images. PMID:24611403

  2. A Likely Micro-Quasar in the Shadow of M82 X-1

    NASA Astrophysics Data System (ADS)

    Xu, Xiao-jie; Liu, Jifeng; Liu, Jiren

    2015-02-01

    The ultra-luminous X-ray source M82 X-1 is one of the most promising intermediate mass black hole candidates in the local universe based on its high X-ray luminosities (1040-1041 erg s-1) and quasi-periodic oscillations, and is possibly associated with a radio flare source. In this work, applying the sub-pixel technique to the 120 ks Chandra observation (ID: 10543) of M82 X-1, we split M82 X-1 into two sources separated by 1.″1. The secondary source is not detected in other M82 observations. The radio flare source is not found to associate with M82 X-1, but is instead associated with the nearby transient source S1 with an outburst luminosity of ˜1039 erg s-1. With X-ray outburst and radio flare activities analogous to the recently discovered micro-quasar in M31, S1 is likely to be a micro-quasar hidden in the shadow of M82 X-1.

  3. Position determination and measurement error analysis for the spherical proof mass with optical shadow sensing

    NASA Astrophysics Data System (ADS)

    Hou, Zhendong; Wang, Zhaokui; Zhang, Yulin

    2016-09-01

    To meet the very demanding requirements for space gravity detection, the gravitational reference sensor (GRS) as the key payload needs to offer the relative position of the proof mass with extraordinarily high precision and low disturbance. The position determination and error analysis for the GRS with a spherical proof mass is addressed. Firstly the concept of measuring the freely falling proof mass with optical shadow sensors is presented. Then, based on the optical signal model, the general formula for position determination is derived. Two types of measurement system are proposed, for which the analytical solution to the three-dimensional position can be attained. Thirdly, with the assumption of Gaussian beams, the error propagation models for the variation of spot size and optical power, the effect of beam divergence, the chattering of beam center, and the deviation of beam direction are given respectively. Finally, the numerical simulations taken into account of the model uncertainty of beam divergence, spherical edge and beam diffraction are carried out to validate the performance of the error propagation models. The results show that these models can be used to estimate the effect of error source with an acceptable accuracy which is better than 20%. Moreover, the simulation for the three-dimensional position determination with one of the proposed measurement system shows that the position error is just comparable to the error of the output of each sensor.

  4. Measurements of wavefront distortions of optical radiation using a shadow method

    NASA Astrophysics Data System (ADS)

    Bredikhin, Vladimir I.; Kuznetsov, S. P.

    2004-06-01

    The technique for measuring wave front distortions in optical elements by the shadow method is developed. Shadow pictures obtained for mutually perpendicular orientations of the Foucault knife-edge are the distributions of components of the gradient of the function describing the wave front relief, so that its shape can be restored by means of integration. An example of measurements of wave front distortions in large-scale optical KDP crystal elements employing the IAB 451 device is given.

  5. Shadowing and the role of small diffusivity in the chaotic advection of scalars

    NASA Technical Reports Server (NTRS)

    Klapper, I.

    1992-01-01

    Using techniques from shadowing theory, the solution of the scalar advection-diffusion equation is studied. It is shown that, under certain circumstances, the effect of small scalar diffusivity is to smooth the zero-diffusivity solution by averaging local fine-scaled structure against a Gaussian. The method of study depends on shadowing and thus fails for nonuniformly stretching systems, its failure suggesting the ways in which the effects of asymptotically small molecular diffusion can become nonlocal in chaotic fluid flows.

  6. Behavioral responses to a repetitive shadow stimulus express a persistent state of defensive arousal in Drosophila

    PubMed Central

    Gonzalez, Carlos R.; Fernandez, Conchi M.; Ramasamy, Lakshmi; Tabachnik, Tanya; Du, Rebecca R.; Felsen, Panna E.; Maire, Michael M.; Perona, Pietro

    2015-01-01

    Summary The neural circuit mechanisms underlying emotion states remain poorly understood. Drosophila offers powerful genetic approaches for dissecting neural circuit function, but whether flies exhibit emotion-like behaviors has not been clear. We recently proposed that model organisms may express internal states displaying “emotion primitives,” which are general characteristics common to different emotions, rather than specific anthropomorphic emotions such as “fear” or “anxiety”. These emotion primitives include scalability, persistence, valence and generalization to multiple contexts. Here we have applied this approach to determine whether flies' defensive responses to shadows are purely reflexive, or may express underlying emotion states. We describe a new behavioral assay in which flies confined in an enclosed arena are repeatedly exposed to an overhead translational shadow. Repetitive shadows promoted graded (scalable) and persistent increases in locomotor velocity and hopping, and occasional freezing. The shadow also dispersed feeding flies from a food resource, suggesting both negative valence and context generalization. Strikingly, there was a significant delay before the flies returned to the food following shadow-induced dispersal, suggestive of a slowly decaying internal defensive state. The length of this delay was increased when more shadows were delivered for initial dispersal. These responses can be mathematically modeled by assuming an internal state that behaves as a leaky integrator of shadow exposure. Our results suggest that flies' responses to repetitive shadow stimuli express an internal state exhibiting canonical emotion primitives, possibly analogous to “fear” in mammals. The mechanistic basis of this state can now be investigated in a genetically tractable insect species. PMID:25981791

  7. Activation of the Human MT Complex by Motion in Depth Induced by a Moving Cast Shadow.

    PubMed

    Katsuyama, Narumi; Usui, Nobuo; Taira, Masato

    2016-01-01

    A moving cast shadow is a powerful monocular depth cue for motion perception in depth. For example, when a cast shadow moves away from or toward an object in a two-dimensional plane, the object appears to move toward or away from the observer in depth, respectively, whereas the size and position of the object are constant. Although the cortical mechanisms underlying motion perception in depth by cast shadow are unknown, the human MT complex (hMT+) is likely involved in the process, as it is sensitive to motion in depth represented by binocular depth cues. In the present study, we examined this possibility by using a functional magnetic resonance imaging (fMRI) technique. First, we identified the cortical regions sensitive to the motion of a square in depth represented via binocular disparity. Consistent with previous studies, we observed significant activation in the bilateral hMT+, and defined functional regions of interest (ROIs) there. We then investigated the activity of the ROIs during observation of the following stimuli: 1) a central square that appeared to move back and forth via a moving cast shadow (mCS); 2) a segmented and scrambled cast shadow presented beside the square (sCS); and 3) no cast shadow (nCS). Participants perceived motion of the square in depth in the mCS condition only. The activity of the hMT+ was significantly higher in the mCS compared with the sCS and nCS conditions. Moreover, the hMT+ was activated equally in both hemispheres in the mCS condition, despite presentation of the cast shadow in the bottom-right quadrant of the stimulus. Perception of the square moving in depth across visual hemifields may be reflected in the bilateral activation of the hMT+. We concluded that the hMT+ is involved in motion perception in depth induced by moving cast shadow and by binocular disparity. PMID:27597999

  8. Capillary electrophoresis of some free fatty acids using partially aqueous electrolyte systems and indirect UV detection. Application to the analysis of oleic and linoleic acids in peanut breeding lines

    Technology Transfer Automated Retrieval System (TEKTRAN)

    This study has shown for the first time the suitability of CE with a partially aqueous electrolyte system for the analysis of free fatty acids (FFA's) in small portions of single peanut seeds. The partially aqueous electrolyte system consisted of 40 mM Tris, 2.5 mM adenosine-5'-monophosphate (AMP) ...

  9. Gradient shadow pattern reveals refractive index of liquid

    PubMed Central

    Kim, Wonkyoung; Kim, Dong Sung

    2016-01-01

    We propose a simple method that uses a gradient shadow pattern (GSP) to measure the refractive index nL of liquids. A light source generates a “dark-bright-dark” GSP when it is projected through through the back of a transparent, rectangular block with a cylindrical chamber that is filled with a liquid sample. We found that there is a linear relationship between nL and the proportion of the bright region in a GSP, which provides the basic principle of the proposed method. A wide range 1.33 ≤ nL ≤ 1.46 of liquids was measured in the single measurement setup with error <0.01. The proposed method is simple but robust to illuminating conditions, and does not require for any expensive or precise optical components, so we expect that it will be useful in many portable measurement systems that use nL to estimate attributes of liquid samples. PMID:27302603

  10. Kriging in the Shadows: Geostatistical Interpolation for Remote Sensing

    NASA Technical Reports Server (NTRS)

    Rossi, Richard E.; Dungan, Jennifer L.; Beck, Louisa R.

    1994-01-01

    It is often useful to estimate obscured or missing remotely sensed data. Traditional interpolation methods, such as nearest-neighbor or bilinear resampling, do not take full advantage of the spatial information in the image. An alternative method, a geostatistical technique known as indicator kriging, is described and demonstrated using a Landsat Thematic Mapper image in southern Chiapas, Mexico. The image was first classified into pasture and nonpasture land cover. For each pixel that was obscured by cloud or cloud shadow, the probability that it was pasture was assigned by the algorithm. An exponential omnidirectional variogram model was used to characterize the spatial continuity of the image for use in the kriging algorithm. Assuming a cutoff probability level of 50%, the error was shown to be 17% with no obvious spatial bias but with some tendency to categorize nonpasture as pasture (overestimation). While this is a promising result, the method's practical application in other missing data problems for remotely sensed images will depend on the amount and spatial pattern of the unobscured pixels and missing pixels and the success of the spatial continuity model used.

  11. Method for observing phase objects without halos and directional shadows

    NASA Astrophysics Data System (ADS)

    Suzuki, Yoshimasa; Kajitani, Kazuo; Ohde, Hisashi

    2015-03-01

    A new microscopy method for observing phase objects without halos and directional shadows is proposed. The key optical element is an annular aperture at the front focal plane of a condenser with a larger diameter than those used in standard phase contrast microscopy. The light flux passing through the annular aperture is changed by the specimen's surface profile and then passes through an objective and contributes to image formation. This paper presents essential conditions for realizing the method. In this paper, images of colonies formed by induced pluripotent stem (iPS) cells using this method are compared with the conventional phase contrast method and the bright-field method when the NA of the illumination is small to identify differences among these techniques. The outlines of the iPS cells are clearly visible with this method, whereas they are not clearly visible due to halos when using the phase contrast method or due to weak contrast when using the bright-field method. Other images using this method are also presented to demonstrate a capacity of this method: a mouse ovum and superimposition of several different images of mouse iPS cells.

  12. The development of the shadow analysis team concept

    SciTech Connect

    McGuire, R.R.

    1995-11-01

    Part II, Section E, Paragraphs 52-55 of the {open_quotes}Verification Annex{close_quotes} (Annex 2) of the Chemical Weapons Convention (CWC) provides the general rights and obligations of both the Inspected State Party (ISP) and the Inspection Team (IT) as to the collection and analysis of samples. In summary, the inspection team has the right to request the collection of samples which will be collected by the ISP unless the decision is made by the ISP to allow the inspectors to collect them. Samples will, if possible, be analyzed at the inspection site, with the assistance of the ISP if requested by the IT. The ISP has the right to retain portions all collected samples. Samples may be sent off-site for independent analysis if deemed necessary. These rights are modified in the case of {open_quotes}Challenge Inspections{close_quotes} by the {open_quotes}Managed Access{close_quotes} Provisions of Part X, Section C, Paragraphs 4648 which specifies that sample collection is to be negotiated between the Inspection Team and the Inspected State Party. In order to assist the ISP in fulfilling its obligation to assist the IT in determining compliance, and in preserving its rights to protect sensitive information not relevant to the CWC, we propose to establish the Army Material Command Treaty Laboratory (AMCTL) Shadow Analysis Team.

  13. Glacial isostatic stress shadowing by the Antarctic ice sheet

    NASA Technical Reports Server (NTRS)

    Ivins, E. R.; James, T. S.; Klemann, V.

    2005-01-01

    Numerous examples of fault slip that offset late Quaternary glacial deposits and bedrock polish support the idea that the glacial loading cycle causes earthquakes in the upper crust. A semianalytical scheme is presented for quantifying glacial and postglacial lithospheric fault reactivation using contemporary rock fracture prediction methods. It extends previous studies by considering differential Mogi-von Mises stresses, in addition to those resulting from a Coulomb analysis. The approach utilizes gravitational viscoelastodynamic theory and explores the relationships between ice mass history and regional seismicity and faulting in a segment of East Antarctica containing the great Antarctic Plate (Balleny Island) earthquake of 25 March 1998 (Mw 8.1). Predictions of the failure stress fields within the seismogenic crust are generated for differing assumptions about background stress orientation, mantle viscosity, lithospheric thickness, and possible late Holocene deglaciation for the D91 Antarctic ice sheet history. Similar stress fracture fields are predicted by Mogi-von Mises and Coulomb theory, thus validating previous rebound Coulomb analysis. A thick lithosphere, of the order of 150-240 km, augments stress shadowing by a late melting (middle-late Holocene) coastal East Antarctic ice complex and could cause present-day earthquakes many hundreds of kilometers seaward of the former Last Glacial Maximum grounding line.

  14. Slant path L- and S-Band tree shadowing measurements

    NASA Technical Reports Server (NTRS)

    Vogel, Wolfhard J.; Torrence, Geoffrey W.

    1994-01-01

    This contribution presents selected results from simultaneous L- and S-Band slant-path fade measurements through a pecan, a cottonwood, and a pine tree employing a tower-mounted transmitter and dual-frequency receiver. A single, circularly-polarized antenna was used at each end of the link. The objective was to provide information for personal communications satellite design on the correlation of tree shadowing between frequencies near 1620 and 2500 MHz. Fades were measured along 10 m lateral distance with 5 cm spacing. Instantaneous fade differences between L- and S-Band exhibited normal distribution with means usually near 0 dB and standard deviations from 5.2 to 7.5 dB. The cottonwood tree was an exception, with 5.4 dB higher average fading at S- than at L-Band. The spatial autocorrelation reduced to near zero with lags of about 10 lambda. The fade slope in dB/MHz is normally distributed with zero mean and standard deviation increasing with fade level.

  15. Shadow enhancers enable Hunchback bifunctionality in the Drosophila embryo

    PubMed Central

    Staller, Max V.; Vincent, Ben J.; Bragdon, Meghan D. J.; Lydiard-Martin, Tara; Wunderlich, Zeba; Estrada, Javier; DePace, Angela H.

    2015-01-01

    Hunchback (Hb) is a bifunctional transcription factor that activates and represses distinct enhancers. Here, we investigate the hypothesis that Hb can activate and repress the same enhancer. Computational models predicted that Hb bifunctionally regulates the even-skipped (eve) stripe 3+7 enhancer (eve3+7) in Drosophila blastoderm embryos. We measured and modeled eve expression at cellular resolution under multiple genetic perturbations and found that the eve3+7 enhancer could not explain endogenous eve stripe 7 behavior. Instead, we found that eve stripe 7 is controlled by two enhancers: the canonical eve3+7 and a sequence encompassing the minimal eve stripe 2 enhancer (eve2+7). Hb bifunctionally regulates eve stripe 7, but it executes these two activities on different pieces of regulatory DNA—it activates the eve2+7 enhancer and represses the eve3+7 enhancer. These two “shadow enhancers” use different regulatory logic to create the same pattern. PMID:25564665

  16. Gradient shadow pattern reveals refractive index of liquid

    NASA Astrophysics Data System (ADS)

    Kim, Wonkyoung; Kim, Dong Sung

    2016-06-01

    We propose a simple method that uses a gradient shadow pattern (GSP) to measure the refractive index nL of liquids. A light source generates a “dark-bright-dark” GSP when it is projected through through the back of a transparent, rectangular block with a cylindrical chamber that is filled with a liquid sample. We found that there is a linear relationship between nL and the proportion of the bright region in a GSP, which provides the basic principle of the proposed method. A wide range 1.33 ≤ nL ≤ 1.46 of liquids was measured in the single measurement setup with error <0.01. The proposed method is simple but robust to illuminating conditions, and does not require for any expensive or precise optical components, so we expect that it will be useful in many portable measurement systems that use nL to estimate attributes of liquid samples.

  17. Gradient shadow pattern reveals refractive index of liquid.

    PubMed

    Kim, Wonkyoung; Kim, Dong Sung

    2016-01-01

    We propose a simple method that uses a gradient shadow pattern (GSP) to measure the refractive index nL of liquids. A light source generates a "dark-bright-dark" GSP when it is projected through through the back of a transparent, rectangular block with a cylindrical chamber that is filled with a liquid sample. We found that there is a linear relationship between nL and the proportion of the bright region in a GSP, which provides the basic principle of the proposed method. A wide range 1.33 ≤ nL ≤ 1.46 of liquids was measured in the single measurement setup with error <0.01. The proposed method is simple but robust to illuminating conditions, and does not require for any expensive or precise optical components, so we expect that it will be useful in many portable measurement systems that use nL to estimate attributes of liquid samples. PMID:27302603

  18. "Shadow stories" in oral interviews: Narrative care through careful listening.

    PubMed

    de Medeiros, Kate; Rubinstein, Robert L

    2015-08-01

    In most narrative approaches to understanding old age, the primary object of interest is the told story. However, what is often overlooked in narrative research are the untold stories--the silences, gaps, and omissions that form a type of shadow story or a story that lies just below the surface of what is said or written. This paper presents an illustrative case example of Constance to demonstrate how careful listening can help uncover hidden stories in an interview. In this case, Constance mentions two people (her brother and husband) as being important in her life yet omits them from the majority of her interview. The interviewer is able to uncover a hidden story with regard to her brother, learning important details about their relationship that would have otherwise gone unspoken. Overall, findings point to the importance of untold stories both in terms of content and as a way to empower the speaker to address topics that he or she may have otherwise thought were not of interest to the interviewer. PMID:26162737

  19. AVIRIS calibration using the cloud-shadow method

    NASA Technical Reports Server (NTRS)

    Carder, K. L.; Reinersman, P.; Chen, R. F.

    1993-01-01

    More than 90 percent of the signal at an ocean-viewing, satellite sensor is due to the atmosphere, so a 5 percent sensor-calibration error viewing a target that contributes but 10 percent of the signal received at the sensor may result in a target-reflectance error of more than 50 percent. Since prelaunch calibration accuracies of 5 percent are typical of space-sensor requirements, recalibration of the sensor using ground-base methods is required for low-signal target. Known target reflectance or water-leaving radiance spectra and atmospheric correction parameters are required. In this article we describe an atmospheric-correction method that uses cloud shadowed pixels in combination with pixels in a neighborhood region of similar optical properties to remove atmospheric effects from ocean scenes. These neighboring pixels can then be used as known reflectance targets for validation of the sensor calibration and atmospheric correction. The method uses the difference between water-leaving radiance values for these two regions. This allows nearly identical optical contributions to the two signals (e.g., path radiance and Fresnel-reflected skylight) to be removed, leaving mostly solar photons backscattered from beneath the sea to dominate the residual signal. Normalization by incident solar irradiance reaching the sea surface provides the remote-sensing reflectance of the ocean at the location of the neighbor region.

  20. Generating CAHV and CAHVOR Images with Shadows in ROAMS

    NASA Technical Reports Server (NTRS)

    Madison, Richard; Jain, Abhinandan; Pomerantz, Marc

    2006-01-01

    Part of the Rover Analysis, Modeling and Simulation (ROAMS) software that synthesizes images of terrain has been augmented to make the images more realistic. [ROAMS was described in "Simulating Operation of a Planetary Rover" (NPO-30722), NASA Tech Briefs, Vol. 28, No. 9 (September 2004), page 52. ROAMS simulates the operation of a robotic vehicle (rover) exploring terrain on a remote planet.] The images are needed for modeling responses of rover cameras that provide sensory inputs for machine-vision-based algorithms for controlling the motion of the rover. The augmented image-synthesizing part of the ROAMS software supports terrain geometry and texture specifiable by the user, CAHV and CAHVOR camera models, and more-realistic shadowing (see figure). (The letters in "CAHV" represent vectors in a standard photogrammetric model of a pinhole camera. Letters O and R in "CAHVOR" represent vectors used to model distortions.) A contemplated future version of ROAMS would support the CAHVORE model, which represents more-general cameras, including those having fish-eye or other wide-field-of-view lenses. (Letter E in "CAHVORE" represents a vector used to model apparent motion of a camera entrance pupil.)