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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.

  2. Robust road detection in shadow conditions

    NASA Astrophysics Data System (ADS)

    Lu, Kaiyue; Xia, Siyu; Zhang, Junkang; Qin, A. Kai

    2016-07-01

    Image-based road detection is a vital task for many real-world applications, such as autonomous driving and obstacle detection. We propose a method for segmenting road regions from a single image based on horizon line estimation and clustering technology. The key idea is to leverage normalized cross correlation to search for the line separating the road image. Additionally, we divide the lower part of the road image into several identical parts horizontally and utilize a density-peak clustering algorithm in terms of gray and HSV value of each pixel. Clustering results are further labeled as road and nonroad based on the assumption that two adjacent horizontal parts share similar clustering size and average gray value. For road images with shadows, we also propose a new shadow-free space derived from HSV space. By calculating maximum entropy and reconstructing images, we show that shadows are eliminated to achieve better road detection. Experimental results on four datasets and shadow images demonstrate the effectiveness and robustness of our method.

  3. Shadow detection and removal based on the saliency map

    NASA Astrophysics Data System (ADS)

    Fang, Zhiwen; Cao, Zhiguo; Deng, Chunhua; Yan, Ruicheng; Qin, Yueming

    2013-10-01

    The detection of shadow is the first step to reduce the imaging effect that is caused by the interactions of the light source with surfaces, and then shadow removal can recover the vein information from the dark region. In this paper, we have presented a new method to detect the shadow in a single nature image with the saliency map and to remove the shadow. Firstly, RGB image is transferred to 2D module in order to improve the blue component. Secondly, saliency map of blue component is extracted via graph-based manifold ranking. Then the edge of the shadow can be detected in order to recover the transitional region between the shadow and non-shadow region. Finally, shadow is compensated by enhancing the image in RGB space. Experimental results show the effectiveness of the proposed method.

  4. Exposing Image Forgery by Detecting Consistency of Shadow

    PubMed Central

    Ke, Yongzhen; Qin, Fan; Min, Weidong; Zhang, Guiling

    2014-01-01

    We propose two tampered image detection methods based on consistency of shadow. The first method is based on texture consistency of shadow for the first kind of splicing image, in which the shadow as well as main body is copied and pasted from another image. The suspicious region including shadow and nonshadow is first selected. Then texture features of the shadow region and the nonshadow region are extracted. Last, correlation function is used to measure the similarity of the two texture features. By comparing the similarity, we can judge whether the image is tampered. Due to the failure in detecting the second kind of splicing image, in which main body, its shadow, and surrounding regions are copied and pasted from another image, another method based on strength of light source of shadows is proposed. The two suspicious shadow regions are first selected. Then an efficient method is used to estimate the strength of light source of shadow. Last, the similarity of strength of light source of two shadows is measured by correlation function. By combining the two methods, we can detect forged image with shadows. Experimental results demonstrate that the proposed methods are effective despite using simplified model compared with the existing methods. PMID:24757419

  5. Exposing image forgery by detecting consistency of shadow.

    PubMed

    Ke, Yongzhen; Qin, Fan; Min, Weidong; Zhang, Guiling

    2014-01-01

    We propose two tampered image detection methods based on consistency of shadow. The first method is based on texture consistency of shadow for the first kind of splicing image, in which the shadow as well as main body is copied and pasted from another image. The suspicious region including shadow and nonshadow is first selected. Then texture features of the shadow region and the nonshadow region are extracted. Last, correlation function is used to measure the similarity of the two texture features. By comparing the similarity, we can judge whether the image is tampered. Due to the failure in detecting the second kind of splicing image, in which main body, its shadow, and surrounding regions are copied and pasted from another image, another method based on strength of light source of shadows is proposed. The two suspicious shadow regions are first selected. Then an efficient method is used to estimate the strength of light source of shadow. Last, the similarity of strength of light source of two shadows is measured by correlation function. By combining the two methods, we can detect forged image with shadows. Experimental results demonstrate that the proposed methods are effective despite using simplified model compared with the existing methods.

  6. A novel method to detect shadows on multispectral images

    NASA Astrophysics Data System (ADS)

    Daǧlayan Sevim, Hazan; Yardımcı ćetin, Yasemin; Özışık Başkurt, Didem

    2016-10-01

    Shadowing occurs when the direct light coming from a light source is obstructed by high human made structures, mountains or clouds. Since shadow regions are illuminated only by scattered light, true spectral properties of the objects are not observed in such regions. Therefore, many object classification and change detection problems utilize shadow detection as a preprocessing step. Besides, shadows are useful for obtaining 3D information of the objects such as estimating the height of buildings. With pervasiveness of remote sensing images, shadow detection is ever more important. This study aims to develop a shadow detection method on multispectral images based on the transformation of C1C2C3 space and contribution of NIR bands. The proposed method is tested on Worldview-2 images covering Ankara, Turkey at different times. The new index is used on these 8-band multispectral images with two NIR bands. The method is compared with methods in the literature.

  7. Satellite images analysis for shadow detection and building height estimation

    NASA Astrophysics Data System (ADS)

    Liasis, Gregoris; Stavrou, Stavros

    2016-09-01

    Satellite images can provide valuable information about the presented urban landscape scenes to remote sensing and telecommunication applications. Obtaining information from satellite images is difficult since all the objects and their surroundings are presented with feature complexity. The shadows cast by buildings in urban scenes can be processed and used for estimating building heights. Thus, a robust and accurate building shadow detection process is important. Region-based active contour models can be used for satellite image segmentation. However, spectral heterogeneity that usually exists in satellite images and the feature similarity representing the shadow and several non-shadow regions makes building shadow detection challenging. In this work, a new automated method for delineating building shadows is proposed. Initially, spectral and spatial features of the satellite image are utilized for designing a custom filter to enhance shadows and reduce intensity heterogeneity. An effective iterative procedure using intensity differences is developed for tuning and subsequently selecting the most appropriate filter settings, able to highlight the building shadows. The response of the filter is then used for automatically estimating the radiometric property of the shadows. The customized filter and the radiometric feature are utilized to form an optimized active contour model where the contours are biased to delineate shadow regions. Post-processing morphological operations are also developed and applied for removing misleading artefacts. Finally, building heights are approximated using shadow length and the predefined or estimated solar elevation angle. Qualitative and quantitative measures are used for evaluating the performance of the proposed method for both shadow detection and building height estimation.

  8. Development of Pressure Shadows in Partially Molten Rocks

    NASA Astrophysics Data System (ADS)

    Sundberg, M.; Zimmerman, M. E.; Kohlstedt, D. L.

    2002-12-01

    To investigate the factors involved in the formation of pressure sha-dows, we have deformed a series of synthetic rock samples in triaxial compression and simple shear. Our fine-grained (~15 μm) samples are composed of either 95% San Carlos olivine + 5% MORB, 93% San Carlos olivine + 2% FeS+ 5% MORB, or 95% Beaver Bay anorthite + 5% MORB. Additionally, we placed 5-30 small (~1 mm diameter), approximately spherical zirconia inclusions in each sample. Compression samples were deformed to strains of 10-20%, and shear samples were deformed to a shear strain of 250%. These experiments were performed at P = 300 MPa and T = 1523K for the olivine-rich samples and T = 1473 K for the anorthite-rich samples in a gas-medium pressure apparatus with differential stresses between 10 and 100 MPa. Our results indicate that significant migration of melt can occur under these conditions. In the olivine + MORB compression samples deformed to a strain of 20%, melt depleted lobes with ~0.5 the original melt concentration develop in the region of maximum compressive stresses, and melt-rich regions containing about 1.5 to 2.0 times the original melt concentration occur in the region of minimum compressive stress. In all olivine + MORB compression samples a halo of higher melt density surrounds the inclusion. The melt redistribution is the most pronounced in the sheared samples, forming regions of high melt concentration (~2.0 to 2.5 times the original concentration) in the low-pressure regions around the inclusion. To investigate the effect of compaction length (δc = (kη /μ )1/2, where k is the permeability, η the shear viscosity, and μ the melt viscosity) on the development of pressure shadows, the results on the olivine + MORB samples were compared to those on olivine + MORB + FeS and anorthite + MORB. The addition of FeS reduces the permeability and hence compaction length relative to the olivine + MORB samples (~1 mm versus ~10 mm). The resulting melt distribution was more

  9. Physical models for moving shadow and object detection in video.

    PubMed

    Nadimi, Sohail; Bhanu, Bir

    2004-08-01

    Current moving object detection systems typically detect shadows cast by the moving object as part of the moving object. In this paper, the problem of separating moving cast shadows from the moving objects in an outdoor environment is addressed. Unlike previous work, we present an approach that does not rely on any geometrical assumptions such as camera location and ground surface/object geometry. The approach is based on a new spatio-temporal albedo test and dichromatic reflection model and accounts for both the sun and the sky illuminations. Results are presented for several video sequences representing a variety of ground materials when the shadows are cast on different surface types. These results show that our approach is robust to widely different background and foreground materials, and illuminations.

  10. Shadow-Based Vehicle Detection in Urban Traffic.

    PubMed

    Ibarra-Arenado, Manuel; Tjahjadi, Tardi; Pérez-Oria, Juan; Robla-Gómez, Sandra; Jiménez-Avello, Agustín

    2017-04-27

    Vehicle detection is a fundamental task in Forward Collision Avoiding Systems (FACS). Generally, vision-based vehicle detection methods consist of two stages: hypotheses generation and hypotheses verification. In this paper, we focus on the former, presenting a feature-based method for on-road vehicle detection in urban traffic. Hypotheses for vehicle candidates are generated according to the shadow under the vehicles by comparing pixel properties across the vertical intensity gradients caused by shadows on the road, and followed by intensity thresholding and morphological discrimination. Unlike methods that identify the shadow under a vehicle as a road region with intensity smaller than a coarse lower bound of the intensity for road, the thresholding strategy we propose determines a coarse upper bound of the intensity for shadow which reduces false positives rates. The experimental results are promising in terms of detection performance and robustness in day time under different weather conditions and cluttered scenarios to enable validation for the first stage of a complete FACS.

  11. Shadow-Based Vehicle Detection in Urban Traffic

    PubMed Central

    Ibarra-Arenado, Manuel; Tjahjadi, Tardi; Pérez-Oria, Juan; Robla-Gómez, Sandra; Jiménez-Avello, Agustín

    2017-01-01

    Vehicle detection is a fundamental task in Forward Collision Avoiding Systems (FACS). Generally, vision-based vehicle detection methods consist of two stages: hypotheses generation and hypotheses verification. In this paper, we focus on the former, presenting a feature-based method for on-road vehicle detection in urban traffic. Hypotheses for vehicle candidates are generated according to the shadow under the vehicles by comparing pixel properties across the vertical intensity gradients caused by shadows on the road, and followed by intensity thresholding and morphological discrimination. Unlike methods that identify the shadow under a vehicle as a road region with intensity smaller than a coarse lower bound of the intensity for road, the thresholding strategy we propose determines a coarse upper bound of the intensity for shadow which reduces false positives rates. The experimental results are promising in terms of detection performance and robustness in day time under different weather conditions and cluttered scenarios to enable validation for the first stage of a complete FACS. PMID:28448465

  12. The research on the shadow detection from high resolution remote sensing imagery

    NASA Astrophysics Data System (ADS)

    Chen, Zhong; Zhou, Heng; Deng, Tao; Luo, Song

    2013-10-01

    Shadow is one of the basic characteristics in urban remote sensed imagery. It affects the extraction of object's edge, identification of objects and registration of images, so shadow detection has a great importance in urban remote sensing. In this paper, a kind of method with HSV is proposed to detect shadow from the color high resolution remote sensing imagery mainly through a series of processing steps including twice HSV transformation, self-adaptive segmentation, morphological closing operation and little area removing. At last, the ratio of the shadow is achieved according to the shadow area statistical analysis. The experiments show that the approach can detect the shadow accurately and availably.

  13. Shadow Detection Based on Regions of Light Sources for Object Extraction in Nighttime Video

    PubMed Central

    Lee, Gil-beom; Lee, Myeong-jin; Lee, Woo-Kyung; Park, Joo-heon; Kim, Tae-Hwan

    2017-01-01

    Intelligent video surveillance systems detect pre-configured surveillance events through background modeling, foreground and object extraction, object tracking, and event detection. Shadow regions inside video frames sometimes appear as foreground objects, interfere with ensuing processes, and finally degrade the event detection performance of the systems. Conventional studies have mostly used intensity, color, texture, and geometric information to perform shadow detection in daytime video, but these methods lack the capability of removing shadows in nighttime video. In this paper, a novel shadow detection algorithm for nighttime video is proposed; this algorithm partitions each foreground object based on the object’s vertical histogram and screens out shadow objects by validating their orientations heading toward regions of light sources. From the experimental results, it can be seen that the proposed algorithm shows more than 93.8% shadow removal and 89.9% object extraction rates for nighttime video sequences, and the algorithm outperforms conventional shadow removal algorithms designed for daytime videos. PMID:28327515

  14. Dual tree complex wavelet transform based shadow detection and removal from moving objects

    NASA Astrophysics Data System (ADS)

    Khare, Manish; Srivastava, Rajneesh K.; Khare, Ashish

    2014-02-01

    Presence of shadow degrades performance of any computer vision system as a number of shadow points are always misclassified as object points. Various algorithms for shadow detection and removal exist for still images but very few algorithms have been developed for moving objects. This paper introduces a new method for shadow detection and removal from moving object which is based on Dual tree complex wavelet transform. We have chosen Dual tree complex wavelet transform as it is shift invariant and have a better edge detection property as compared to real valued wavelet transform. In the present work, shadow detection and removal has been done by thresholding wavelet coefficients of Dual tree complex wavelet transform of difference of reference frame and the current frame. Standard deviation of wavelet coefficients is used as an optimal threshold. Results after visual and quantitative performance metrics computation shows that the proposed method for shadow detection and removal is better than other state-of-theart methods.

  15. 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.

  16. Shadow detection in camera-based vehicle detection: survey and analysis

    NASA Astrophysics Data System (ADS)

    Barcellos, Pablo; Gomes, Vitor; Scharcanski, Jacob

    2016-09-01

    The number of vehicles in circulation in modern urban centers has greatly increased, which motivates the development of automatic traffic monitoring systems. Consequently, camera-based traffic monitoring systems are becoming more widely used, since they offer important technological advantages in comparison with traditional traffic monitoring systems (e.g., simpler maintenance and more flexibility for the design of practical configurations). The segmentation of the foreground (i.e., vehicles) is a fundamental step in the workflow of a camera-based traffic monitoring system. However, foreground segmentation can be negatively affected by vehicle shadows. This paper discusses the types of shadow detection methods available in the literature, their advantages, disadvantages, and in which situations these methods can improve camera-based vehicle detection for traffic monitoring. In order to compare the performance of these different types of shadow detection methods, experiments are conducted with typical methods of each category using publicly available datasets. This work shows that shadow detection definitely can improve the reliability of traffic monitoring systems, but the choice of the type of shadow method depends on the system specifications (e.g., tolerated error), the availability of computational resources, and prior information about the scene and its illumination in regular operation conditions.

  17. Shadow detection of the high-resolution remote sensing image based on pulse coupled neural network

    NASA Astrophysics Data System (ADS)

    Huang, Wei; Xiao, Yu; Lu, Shan

    2011-12-01

    Traditional shadow detection methods are usually detected shadow areas by the single threshold in shadow feature map. This leads to the detection results susceptible to affect by noise, and some special target (high-bright objects and green vegetation etc.) susceptible to misdetection. In this paper, a shadow detection method is proposed based on pulse coupled neural network (PCNN). The model can ignore small differences of pixels values in one area, because the network output is not only associated with the pixel brightness but also associated with pixel spatial location. Firstly, a new shadow feature map is build. Then PCNN model is applied to get optimal detection result with max entropy. The experimental results showed that the proposed model performed better than the single threshold models.

  18. 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.

  19. Practical method of shadow detection and removal for high spatial resolution remote sensing image

    NASA Astrophysics Data System (ADS)

    Li, Ru; Zhang, Bing; Zhang, Xia; Chen, Zhengchao; Wei, Zheng; Zheng, Lanfen

    2007-11-01

    High spatial resolution remote sensing image (HSRRSI) has received a warm welcome in many fields. However, building shadows of large area on HSRRSI (up to 30% in some cases) are one of the biggest hindrances for further applications in many fields. To keep a balance between precision and efficiency required by applications during shadow removal, this paper introduces a creative and practical strategy based on the theory of the pulse coupled neural network (PCNN). By applying the simplified model of PCNN, shadows on HSRRSI had been detected and removed respectively. When applied to HSRRSI, the method could not only remove the shadows, but also keep the contrast between removed areas with shadows and other areas without shadows from being too big, which might distort the image. Therefore the satisfactory result is gained.

  20. Performance Improvement of Partially Shaded Photovoltaic Arrays under Moving Shadow Conditions through Shade Dispersion

    NASA Astrophysics Data System (ADS)

    Vijayalekshmy, S.; Bindu, G. R.; Rama Iyer, S.

    2016-12-01

    Photovoltaic arrays, which are prone to partial shading (PS) reduce the output power than the real power rating of the array. This paper presents the comparative analyses on the electrical characteristics and power losses of a conventional totally cross tied (TCT) configuration, and rearranged TCT (RTCT) in which the modules are physically rearranged in such a way that there is an improvement of power output of array under moving illumination condition (moving cloud). In RTCT, the physical position of the modules is organized based on the Sudoku puzzle pattern so as to scatter the shading effect over the entire array. The rearrangement of modules is performed without varying the electrical connection of the modules in the array. It is validated that the power generation of array under amoving shadow condition is enhanced and the various PS losses are reduced in rearranged configuration.

  1. 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.

  2. 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.

  3. 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.

  4. Detection of buildings through automatic extraction of shadows in Ikonos imagery

    NASA Astrophysics Data System (ADS)

    Armesto Gonzalaz, Julia; Gil Docampo, Mariluz L.; Canas Guerrero, Ignacio

    2004-02-01

    The extraction of man-made objects from remotely sensed imagery is a common application in remote sensing. Building detection is useful in territorial planning, mapping and Geographic Information Systems. Nevertheless these features are difficult to recognise in satellite data because of their variations in structure and size and especially because of the spatial resolution of the imagery. IRS panchromatic data, with 5,8 meters pixel size, was the higher spatial resolution sensor in civil applications until the Ikonos imageries distribution. Several approaches have been proposed for building detection in aerial images. Buildings cast a shadow in some direction and that is why many authors have employed shadows to detect constructions. Other authors use shadows to verify them, once they have been detected by some other techniques. This work focus on shadows detection probabilistic methods: it is found that digital supervised classification of the first principal component obtained from the application of a principal component analysis on the four channels of Ikonos allows identifying shadows and distinguishing them from other covers in the image. It is a fast and effective method and it can be implemented through tools available in commercial remote sensing software. This shadow detection system will provide cost-effectiveness in the inventorying of buildings, especially in areas of dispersed settlement, given that it significantly reduces fieldwork, and even can function as a support and test of the methods of automatic extraction of buildings from satellite images developed up to now.

  5. Fast Occlusion and Shadow Detection for High Resolution Remote Sensing Image Combined with LIDAR Point Cloud

    NASA Astrophysics Data System (ADS)

    Hu, X.; Li, X.

    2012-08-01

    The orthophoto is an important component of GIS database and has been applied in many fields. But occlusion and shadow causes the loss of feature information which has a great effect on the quality of images. One of the critical steps in true orthophoto generation is the detection of occlusion and shadow. Nowadays LiDAR can obtain the digital surface model (DSM) directly. Combined with this technology, image occlusion and shadow can be detected automatically. In this paper, the Z-Buffer is applied for occlusion detection. The shadow detection can be regarded as a same problem with occlusion detection considering the angle between the sun and the camera. However, the Z-Buffer algorithm is computationally expensive. And the volume of scanned data and remote sensing images is very large. Efficient algorithm is another challenge. Modern graphics processing unit (GPU) is much more powerful than central processing unit (CPU). We introduce this technology to speed up the Z-Buffer algorithm and get 7 times increase in speed compared with CPU. The results of experiments demonstrate that Z-Buffer algorithm plays well in occlusion and shadow detection combined with high density of point cloud and GPU can speed up the computation significantly.

  6. Shadow detection in color aerial images based on HSI space and color attenuation relationship

    NASA Astrophysics Data System (ADS)

    Shi, Wenxuan; Li, Jie

    2012-12-01

    Many problems in image processing and computer vision arise from shadows in a single color aerial image. This article presents a new algorithm by which shadows are extracted from a single color aerial image. Apart from using the ratio value of the hue over the intensity in some state-of-the-art algorithms, this article introduces another ratio map, which is obtained by applying the saturation over the intensity. Candidate shadow and nonshadow regions are separated by applying Otus's thresholding method. The color attenuation relationship that describes the relationship between the attenuation of each color channel is derived from the Planck's blackbody irradiance law. For each region, the color attenuation relationship and other determination conditions are performed iteratively to segment it into smaller sub-regions and to identify whether each sub-region is a true shadow region. Compared with previous methods, the proposed algorithm presents better shadow detection accuracy in the images that contain some dark green lawn, river, or low brightness shadow regions. The experimental results demonstrate the advantage of the proposed algorithm.

  7. Shadow detection and removal in RGB VHR images for land use unsupervised classification

    NASA Astrophysics Data System (ADS)

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

    2016-09-01

    Nowadays, high resolution aerial images are widely available thanks to the diffusion of advanced technologies such as UAVs (Unmanned Aerial Vehicles) and new satellite missions. Although these developments offer new opportunities for accurate land use analysis and change detection, cloud and terrain shadows actually limit benefits and possibilities of modern sensors. Focusing on the problem of shadow detection and removal in VHR color images, the paper proposes new solutions and analyses how they can enhance common unsupervised classification procedures for identifying land use classes related to the CO2 absorption. To this aim, an improved fully automatic procedure has been developed for detecting image shadows using exclusively RGB color information, and avoiding user interaction. Results show a significant accuracy enhancement with respect to similar methods using RGB based indexes. Furthermore, novel solutions derived from Procrustes analysis have been applied to remove shadows and restore brightness in the images. In particular, two methods implementing the so called ;anisotropic Procrustes; and the ;not-centered oblique Procrustes; algorithms have been developed and compared with the linear correlation correction method based on the Cholesky decomposition. To assess how shadow removal can enhance unsupervised classifications, results obtained with classical methods such as k-means, maximum likelihood, and self-organizing maps, have been compared to each other and with a supervised clustering procedure.

  8. 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

  9. On the detection of the Moon shadow with the ANTARES neutrino telescope

    NASA Astrophysics Data System (ADS)

    Distefano, C.; ANTARES Collaboration

    2011-01-01

    We discuss the possibility of detecting the Moon shadow with the ANTARES neutrino telescope. A detailed Monte Carlo simulation was conducted in order to calculate the expected significance for the measurement. Simulation results show that the ANTARES telescope will be able to observe the effect in a couple of years. Results of the simulation study will be presented and discussed.

  10. Visual sensor based abnormal event detection with moving shadow removal in home healthcare applications.

    PubMed

    Lee, Young-Sook; Chung, Wan-Young

    2012-01-01

    Vision-based abnormal event detection for home healthcare systems can be greatly improved using visual sensor-based techniques able to detect, track and recognize objects in the scene. However, in moving object detection and tracking processes, moving cast shadows can be misclassified as part of objects or moving objects. Shadow removal is an essential step for developing video surveillance systems. The goal of the primary is to design novel computer vision techniques that can extract objects more accurately and discriminate between abnormal and normal activities. To improve the accuracy of object detection and tracking, our proposed shadow removal algorithm is employed. Abnormal event detection based on visual sensor by using shape features variation and 3-D trajectory is presented to overcome the low fall detection rate. The experimental results showed that the success rate of detecting abnormal events was 97% with a false positive rate of 2%. Our proposed algorithm can allow distinguishing diverse fall activities such as forward falls, backward falls, and falling asides from normal activities.

  11. Automated detection of buildings from single VHR multispectral images using shadow information and graph cuts

    NASA Astrophysics Data System (ADS)

    Ok, Ali Ozgun

    2013-12-01

    In this study, we propose a novel methodology for automated detection of buildings from single very-high-resolution (VHR) multispectral images. The methodology uses the principal evidence of buildings: the shadows that they cast. We model the directional spatial relationship between buildings and their shadows using a recently proposed probabilistic landscape approach. An effective shadow post-processing step is developed to focus on landscapes that belong to building regions. The building regions are detected using an original two-level graph theory approach. In the first level, each shadow region is addressed separately, and building regions are identified via iterative graph cuts designed in two-label partitioning. The final building regions are characterised in a second level in which the previously labelled building regions are subjected to a single-step multi-label graph optimisation performed over the entire image domain. Numerical assessments performed on 16 VHR GeoEye-1 images demonstrate that the proposed approach is highly robust and reliable. A distinctive specialty of the proposed approach is its applicability to buildings with diverse characteristics as well as to VHR images with significantly different illumination properties.

  12. Moon Shadow, Planet Shadow

    NASA Image and Video Library

    2010-05-12

    Saturn moon Prometheus casts a narrow shadow on the rings near the much larger shadow cast by the planet in this image taken by NASA Cassini spacecraft about five months after Saturn August 2009 equinox.

  13. 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.

  14. Automated Detection Framework of the Calcified Plaque with Acoustic Shadowing in IVUS Images

    PubMed Central

    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. Evaluation of Pan-Sharpening Methods for Automatic Shadow Detection in High Resolution Images of Urban Areas

    NASA Astrophysics Data System (ADS)

    de Azevedo, Samara C.; Singh, Ramesh P.; da Silva, Erivaldo A.

    2017-04-01

    Finer spatial resolution of areas with tall objects within urban environment causes intense shadows that lead to wrong information in urban mapping. Due to the shadows, automatic detection of objects (such as buildings, trees, structures, towers) and to estimate the surface coverage from high spatial resolution is difficult. Thus, automatic shadow detection is the first necessary preprocessing step to improve the outcome of many remote sensing applications, particularly for high spatial resolution images. Efforts have been made to explore spatial and spectral information to evaluate such shadows. In this paper, we have used morphological attribute filtering to extract contextual relations in an efficient multilevel approach for high resolution images. The attribute selected for the filtering was the area estimated from shadow spectral feature using the Normalized Saturation-Value Difference Index (NSVDI) derived from pan-sharpening images. In order to assess the quality of fusion products and the influence on shadow detection algorithm, we evaluated three pan-sharpening methods - Intensity-Hue-Saturation (IHS), Principal Components (PC) and Gran-Schmidt (GS) through the image quality measures: Correlation Coefficient (CC), Root Mean Square Error (RMSE), Relative Dimensionless Global Error in Synthesis (ERGAS) and Universal Image Quality Index (UIQI). Experimental results over Worldview II scene from São Paulo city (Brazil) show that GS method provides good correlation with original multispectral bands with no radiometric and contrast distortion. The automatic method using GS method for NSDVI generation clearly provide a clear distinction of shadows and non-shadows pixels with an overall accuracy more than 90%. The experimental results confirm the effectiveness of the proposed approach which could be used for further shadow removal and reliable for object recognition, land-cover mapping, 3D reconstruction, etc. especially in developing countries where land use and

  16. 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.

  17. 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.

  18. Neptune Shadows

    NASA Image and Video Library

    1999-10-15

    This image of Neptune shows the discovery of shadows in Neptune atmosphere, shadows cast onto a deep cloud band by small elevated clouds. They are the first cloud shadows ever seen by NASA Voyager on any planet.

  19. CSMET: Comparative Genomic Motif Detection via Multi-Resolution Phylogenetic Shadowing

    PubMed Central

    Kolar, Mladen; Xing, Eric P.

    2008-01-01

    Functional turnover of transcription factor binding sites (TFBSs), such as whole-motif loss or gain, are common events during genome evolution. Conventional probabilistic phylogenetic shadowing methods model the evolution of genomes only at nucleotide level, and lack the ability to capture the evolutionary dynamics of functional turnover of aligned sequence entities. As a result, comparative genomic search of non-conserved motifs across evolutionarily related taxa remains a difficult challenge, especially in higher eukaryotes, where the cis-regulatory regions containing motifs can be long and divergent; existing methods rely heavily on specialized pattern-driven heuristic search or sampling algorithms, which can be difficult to generalize and hard to interpret based on phylogenetic principles. We propose a new method: Conditional Shadowing via Multi-resolution Evolutionary Trees, or CSMET, which uses a context-dependent probabilistic graphical model that allows aligned sites from different taxa in a multiple alignment to be modeled by either a background or an appropriate motif phylogeny conditioning on the functional specifications of each taxon. The functional specifications themselves are the output of a phylogeny which models the evolution not of individual nucleotides, but of the overall functionality (e.g., functional retention or loss) of the aligned sequence segments over lineages. Combining this method with a hidden Markov model that autocorrelates evolutionary rates on successive sites in the genome, CSMET offers a principled way to take into consideration lineage-specific evolution of TFBSs during motif detection, and a readily computable analytical form of the posterior distribution of motifs under TFBS turnover. On both simulated and real Drosophila cis-regulatory modules, CSMET outperforms other state-of-the-art comparative genomic motif finders. PMID:18535663

  20. Shadow Strands

    NASA Image and Video Library

    2006-06-02

    The soft, sweeping shadows of Saturn C ring cover bright patches of clouds in the planet atmosphere. The shadow-throwing rings stretch across the view at bottom. The dark inner edge of the B ring is visible at top

  1. Stretched Shadow

    NASA Image and Video Library

    2010-03-05

    The shadow of Saturn moon Dione, cast onto the planet, is elongated in dramatic fashion in this image captured by NASA Cassini spacecraft. The moon itself does not appear here, but the shadow can be seen south of the ringplane.

  2. 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.

  3. 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.

  4. 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

  5. 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.

  6. 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.

  7. 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.

  8. 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…

  9. Cool Shadow

    NASA Image and Video Library

    2013-10-17

    The shadow of Saturn cuts across the rings as seen by NASA Cassini spacecraft. As the ring particles enter Saturn shadow, their temperature drops to even colder temperatures, only to warm back up again when they re-emerge into the sunlight.

  10. 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…

  11. A New SAR Image Segmentation Algorithm for the Detection of Target and Shadow Regions

    NASA Astrophysics Data System (ADS)

    Huang, Shiqi; Huang, Wenzhun; Zhang, Ting

    2016-12-01

    The most distinctive characteristic of synthetic aperture radar (SAR) is that it can acquire data under all weather conditions and at all times. However, its coherent imaging mechanism introduces a great deal of speckle noise into SAR images, which makes the segmentation of target and shadow regions in SAR images very difficult. This paper proposes a new SAR image segmentation method based on wavelet decomposition and a constant false alarm rate (WD-CFAR). The WD-CFAR algorithm not only is insensitive to the speckle noise in SAR images but also can segment target and shadow regions simultaneously, and it is also able to effectively segment SAR images with a low signal-to-clutter ratio (SCR). Experiments were performed to assess the performance of the new algorithm on various SAR images. The experimental results show that the proposed method is effective and feasible and possesses good characteristics for general application.

  12. A New SAR Image Segmentation Algorithm for the Detection of Target and Shadow Regions

    PubMed Central

    Huang, Shiqi; Huang, Wenzhun; Zhang, Ting

    2016-01-01

    The most distinctive characteristic of synthetic aperture radar (SAR) is that it can acquire data under all weather conditions and at all times. However, its coherent imaging mechanism introduces a great deal of speckle noise into SAR images, which makes the segmentation of target and shadow regions in SAR images very difficult. This paper proposes a new SAR image segmentation method based on wavelet decomposition and a constant false alarm rate (WD-CFAR). The WD-CFAR algorithm not only is insensitive to the speckle noise in SAR images but also can segment target and shadow regions simultaneously, and it is also able to effectively segment SAR images with a low signal-to-clutter ratio (SCR). Experiments were performed to assess the performance of the new algorithm on various SAR images. The experimental results show that the proposed method is effective and feasible and possesses good characteristics for general application. PMID:27924935

  13. A New SAR Image Segmentation Algorithm for the Detection of Target and Shadow Regions.

    PubMed

    Huang, Shiqi; Huang, Wenzhun; Zhang, Ting

    2016-12-07

    The most distinctive characteristic of synthetic aperture radar (SAR) is that it can acquire data under all weather conditions and at all times. However, its coherent imaging mechanism introduces a great deal of speckle noise into SAR images, which makes the segmentation of target and shadow regions in SAR images very difficult. This paper proposes a new SAR image segmentation method based on wavelet decomposition and a constant false alarm rate (WD-CFAR). The WD-CFAR algorithm not only is insensitive to the speckle noise in SAR images but also can segment target and shadow regions simultaneously, and it is also able to effectively segment SAR images with a low signal-to-clutter ratio (SCR). Experiments were performed to assess the performance of the new algorithm on various SAR images. The experimental results show that the proposed method is effective and feasible and possesses good characteristics for general application.

  14. Northern Shadow

    NASA Image and Video Library

    2012-03-21

    This mosaic of the surface of asteroid Vesta was made from images obtained by NASA Dawn spacecraft while the area was entirely in the sun shadow. Light reflecting off of other areas of Vesta provides the only illumination.

  15. Slanting Shadows

    NASA Image and Video Library

    2009-11-23

    Long shadows stretch away from the towering edge waves created by the gravity of the moon Daphnis in this image taken by NASA Cassini spacecraft a little more than a week before Saturn August 2009 equinox.

  16. Partial turbo detection with reduced complexity

    NASA Astrophysics Data System (ADS)

    Ouardi, Aissa; Djebbari, A.; Bouazza, B. S.

    2011-06-01

    In this article, we propose a novel method for reducing the complexity of the turbo detector MAP (maximum a posteriori). The basic idea consists in turbo detecting a part of intersymbol interference (ISI) after decomposing the channel in two parts. We show that we can reduce the trellis complexity in the turbo process at a certain cost, i.e. performance loss.

  17. Short Shadow

    NASA Image and Video Library

    2017-05-15

    The projection of Saturn's shadow on the rings grows shorter as Saturn's season advances toward northern summer, thanks to the planet's permanent tilt as it orbits the sun. This will continue until Saturn's solstice in May 2017. At that point in time, the shadow will extend only as far as the innermost A ring, leaving the middle and outer A ring completely free of the planet's shadow. Over the course of NASA's Cassini mission, the shadow of Saturn first lengthened steadily until equinox in August 2009. Since then, the shadow has been shrinking. This view looks toward the sunlit side of the rings from about 10 degrees above the ring plane. The image was taken in visible light with the Cassini spacecraft wide-angle camera on Feb. 3, 2017. The view was acquired at a distance of approximately 760,000 miles (1.2 million kilometers) from Saturn. Image scale is 46 miles (73 kilometers) per pixel. https://photojournal.jpl.nasa.gov/catalog/PIA21328

  18. Operation Shadow.

    ERIC Educational Resources Information Center

    Watson, Marilyn Parrish

    Operation Shadow provides materials for a career education program which gives students ages 11-13 an opportunity to relate school subjects to the world of work. Students spend one month in classroom activities, including study of characteristics of self and others and how these characteristics and interests affect one's choice of a life career.…

  19. Coloured Shadows.

    ERIC Educational Resources Information Center

    Olivieri, G.; And Others

    1988-01-01

    Investigates the relationship between knowledge of geometrical optics and the understanding of the phenomenon of colored shadows through adult interviews. Reports that the knowledge of geometrical optics facilitates the pinpointing of the color problem while experience with the mixing of paints may act as a barrier. (Author/YP)

  20. Shadow Below

    NASA Image and Video Library

    2016-06-20

    As Saturn's northern hemisphere summer approaches, the shadows of the rings creep ever southward across the planet. Here, the ring shadows appear to obscure almost the entire southern hemisphere, while the planet's north pole and its six-sided jet stream, known as "the hexagon," are fully illuminated by the sun. When NASA's Cassini spacecraft arrived at Saturn 12 years ago, the shadows of the rings lay far to the north on the planet (see PIA06077). As the mission progressed and seasons turned on the slow-orbiting giant, equinox arrived and the shadows of the rings became a thin line at the equator (see PIA11667). This view looks toward the sunlit side of the rings from about 16 degrees above the ring plane. The image was taken in red light with the Cassini spacecraft wide-angle camera on March 19, 2016. The view was obtained at a distance of approximately 1.7 million miles (2.7 million kilometers) from Saturn and at a Sun-Saturn-spacecraft, or phase, angle of 92 degrees. Image scale is 100 miles (160 kilometers) per pixel. http://photojournal.jpl.nasa.gov/catalog/PIA20486

  1. [Case of cryptogenic organizing pneumonia with radiologically detectable lung cancer after disappearance of infiltrative shadows by steroid treatment].

    PubMed

    Ogata, Kenichi; Morooka, Mitsuyuki

    2008-10-01

    An 82-year-old man with fever and a cough was admitted to hospital. A chest radiograph demonstrated infiltrative shadows in the bilateral middle and lower lung fields and a chest CT scan showed the shadows in the bilateral upper and lower lobes. After admission, infiltrative shadows in the right upper lobe increased and transbronchial lung biopsy (TBLB) specimens disclosed organizing exudates in the alveolar spaces. After steroid treatment, the radiographic infiltrates disappeared but the irregular shadows in the right lower lobe were still present. Lung adenocarcinoma was diagnosed by TBLB specimens of residual shadows. Few cases of cryptogenic organizing pneumonia (COP) with lung cancer have been reported, and further consideration should be given to the relationship between COP and lung cancer. We should consider that diagnostic preparations for chest radiographic imaging can lead to the recognition of several respiratory diseases.

  2. Partial least squares and random sample consensus in outlier detection.

    PubMed

    Peng, Jiangtao; Peng, Silong; Hu, Yong

    2012-03-16

    A novel outlier detection method in partial least squares based on random sample consensus is proposed. The proposed algorithm repeatedly generates partial least squares solutions estimated from random samples and then tests each solution for the support from the complete dataset for consistency. A comparative study of the proposed method and leave-one-out cross validation in outlier detection on simulated data and near-infrared data of pharmaceutical tablets is presented. In addition, a comparison between the proposed method and PLS, RSIMPLS, PRM is provided. The obtained results demonstrate that the proposed method is highly efficient.

  3. 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.

  4. Method of detecting oxygen partial pressure and oxygen partial pressure sensor

    SciTech Connect

    Dees, D.W.

    1991-12-31

    This invention is comprised of 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.

  5. Shadow corrosion

    NASA Astrophysics Data System (ADS)

    Ramasubramanian, N.

    2004-07-01

    An electrochemical mechanism, based on energetically favored complimentary reduction and oxidation reactions, operating in conjunction with radiolysis is proposed for explaining the shadow corrosion phenomenon observed under BWR conditions. The electrochemical reaction on platinum and nickel alloys (Inconel and X-750) is the oxidation of H 2O 2 to produce a localized enhancement in the concentrations of HO 2 and O 2. Energy level of the conduction band of ZrO 2 matches well with that for the reduction of HO 2 and O 2 regenerating H 2O 2. This reduction of the powerful oxidants, stimulates electron emission in ZrO 2 which then is balanced by increased oxidation of zirconium to generate additional electrons and hence also anion vacancies. A coupling between Zircaloy and platinum or nickel alloy is provided by H + transport, the source for initiating shadow corrosion, to Zircaloy-2 (Zircaloy-2 negative relative to platinum or the nickel alloy) in the gap between the materials. An enhanced localized corrosion of Zircaloy-2 occurs, its incidence dependent upon the transport of HO 2, O 2, H + and H 2O 2 in the coolant in the gap.

  6. 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.

  7. 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.

  8. The Moon's Shadow

    NASA Technical Reports Server (NTRS)

    2002-01-01

    Solar eclipses occur when the Moon passes between the Earth and Sun so that the Moon's shadow falls on the Earth. Although solar eclipses are rarely seen at any given location on Earth, they can be observed somewhere on the Earth's surface at least twice and as often as five times per year. Eclipses can be observed by most Earth-orbiting satellites that have wide fields of view. Therefore, scientists working with data sets derived from these satellite sensors should be aware of the reduced solar irradiance within the area of the Moon's shadow. This true-color Moderate-resolution Imaging Spectroradiometer (MODIS) image shows a composite of two adjacent viewing swaths acquired on December 25, 2000 in two consecutive overpasses. The scene covers an area from the Great Lakes in the north to Georgia toward the south. (The full scene covers from Northern Quebec to Florida). Notice that the swath on the left side of the image [acquired at 17:30 UTC (12:30 EST)] is considerably darker than the swath on the right [acquired at 15:50 UTC (10:50 EST)_eclips] due to the Moon's shadow. This eclipse was partial (there was no place on Earth where the Sun was completely hidden behind the Moon). The greatest eclipse occurred in Baffin Island, north of this image, with a maximum eclipse magnitude of 0.72 (72% of the Sun was screened by the Moon at that location). The Moon's shadow (penumbra) extended as far as Nicaragua, much further south of this image. The penumbra covered an area of more than 12000 km diameter on Earth. Image courtesy Jacques Descloitres, MODIS Land Group, NASA Goddard Space Flight Center

  9. 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.

  10. Urban road extraction based on shadow removal and road clues detection from high resolution RGB aerial image

    NASA Astrophysics Data System (ADS)

    Herumurti, Darlis; Uchimura, Keiichi; Koutaki, Gou; Uemura, Takumi

    2014-10-01

    In urban areas, the shadow cast by buildings, trees along the road, abundant objects and complex image texture make the extraction of the road on very high Resolution RGB aerial image very difficult and challenging. We propose a method of road extraction from RGB aerial image in the followings steps: Shadow removal, enhanced sobel transform, keypoints extraction based on Maximally Stable Extremal Regions (MSER), feature extraction based on Speeded Up Robust Features (SURF) and road construction based on multi-resolution segmentation. The experimental results show that the proposed method achieves a good result.

  11. 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.

  12. 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.

  13. Heterodyne efficiency of a detection system for partially coherent beams.

    PubMed

    Salem, Mohamed; Rolland, Jannick P

    2010-05-01

    We consider the heterodyne efficiency as a measure of quality for a coherent detection system. The heterodyne efficiency reflects the matching between the received beam and the local oscillator beam on the detector surface, and one can use this property for the alignment of the system. In this paper we derive a general expression for the heterodyne efficiency of a detection system for beams at any state of coherence, assuming that the propagation directions for the two signals (the received signal and the locally generated one) are slightly different. We derive an analytical expression for the heterodyne efficiency when mixing coherently two partially coherent Gaussian Schell-model beams on a photodetector surface. Numerical examples are given for the variation in the heterodyne efficiency with the misalignment angle, the detector radius, and the parameters of the overlapping beams. We show that partially coherent beams, although they suffer more than coherent beams from a decrease in the heterodyne efficiency, are less affected than coherent beams by the misalignment of the detection system.

  14. Accurate colon residue detection algorithm with partial volume segmentation

    NASA Astrophysics Data System (ADS)

    Li, Xiang; Liang, Zhengrong; Zhang, PengPeng; Kutcher, Gerald J.

    2004-05-01

    Colon cancer is the second leading cause of cancer-related death in the United States. Earlier detection and removal of polyps can dramatically reduce the chance of developing malignant tumor. Due to some limitations of optical colonoscopy used in clinic, many researchers have developed virtual colonoscopy as an alternative technique, in which accurate colon segmentation is crucial. However, partial volume effect and existence of residue make it very challenging. The electronic colon cleaning technique proposed by Chen et al is a very attractive method, which is also kind of hard segmentation method. As mentioned in their paper, some artifacts were produced, which might affect the accurate colon reconstruction. In our paper, instead of labeling each voxel with a unique label or tissue type, the percentage of different tissues within each voxel, which we call a mixture, was considered in establishing a maximum a posterior probability (MAP) image-segmentation framework. A Markov random field (MRF) model was developed to reflect the spatial information for the tissue mixtures. The spatial information based on hard segmentation was used to determine which tissue types are in the specific voxel. Parameters of each tissue class were estimated by the expectation-maximization (EM) algorithm during the MAP tissue-mixture segmentation. Real CT experimental results demonstrated that the partial volume effects between four tissue types have been precisely detected. Meanwhile, the residue has been electronically removed and very smooth and clean interface along the colon wall has been obtained.

  15. Shadows Constructing a Relationship between Light and Color Pigments by Physical and Mathematical Perspectives

    ERIC Educational Resources Information Center

    Yurumezoglu, Kemal; Karabey, Burak; Koyunkaya, Melike Yigit

    2017-01-01

    Full shadows, partial shadows and multilayer shadows are explained based on the phenomenon of the linear dispersion of light. This paper focuses on progressing the understanding of shadows from physical and mathematical perspectives. A significant relationship between light and color pigments is demonstrated with the help of the concept of sets.…

  16. 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

  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. 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.

  19. 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.

  20. Interactive removal and ground truth for difficult shadow scenes

    NASA Astrophysics Data System (ADS)

    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 non-uniform shadow illumination changes, resulting in accurate and robust removal. Another major contribution of this work is the first validated and multi-scene 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 new algorithm to outperform the state-of-the-art across several measures and shadow category. To complement our dataset, an online shadow removal benchmark website is also presented to encourage future open comparisons in this challenging field of research.

  1. Detection of partial-body exposure to ionizing radiation by the automatic detection of dicentrics.

    PubMed

    Vaurijoux, Aurelie; Gregoire, Eric; Roch-Lefevre, Sandrine; Voisin, Pascale; Martin, Cecile; Voisin, Philippe; Roy, Laurence; Gruel, Gaetan

    2012-10-01

    In accidental exposure to ionizing radiation, it is essential to estimate the dose received by the victims. Currently dicentric scoring is the best biological indicator of exposure. The standard biological dosimetry procedure (500 metaphases scored manually) is suitable for a few dose estimations, but the time needed for analysis can be problematic in the case of a large-scale accident. Recently, a new methodology using automatic detection of dicentrics has greatly decreased the time needed for dose estimation and preserves the accuracy of the estimation. However, the capability to detect nonhomogeneous partial-body exposures is an important advantage of dicentric scoring-based biodosimetry, and this remains to be tested with automatic scoring. Thus we analyzed the results obtained with in vitro blood dilutions and in real cases of accidental exposure (partial- or whole-body exposure) using manual scoring and automatic detection of dicentrics. We confirmed that automatic detection allows threefold quicker dicentric scoring than the manual procedure with similar dose estimations and uncertainty intervals. The results concerning partial-body exposures were particularly promising, and homogeneously exposed samples were correctly distinguished from heterogeneously exposed samples containing 5% to 75% of blood irradiated with 2 Gy. In addition, the results obtained for real accident cases were similar whatever the methodology used. This study demonstrates that automatic detection of dicentrics is a credible alternative for recent and acute cases of whole- and partial-body accidental exposures to ionizing radiation.

  2. 2017 Eclipse Shadow Cones

    NASA Image and Video Library

    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...

  3. Mimas Stretched Shadow

    NASA Image and Video Library

    2010-04-22

    The shadow of Saturn moon Mimas is elongated across the planet in this image from NASA Cassini spacecraft. The moon itself is not shown, but the shadow appears just above the ringplane on the right of the image.

  4. Infants' perception of lightness changes related to cast shadows

    PubMed Central

    2017-01-01

    When humans perceive the lightness of an object’s surface in shadows there is an implicit assumption that cast shadows dim the surface. In two experiments, we investigated whether 5- to 8-month-old infants make this assumption about shadows. According to this shadow assumption, the apparent change in lightness produced by shadows on an object’s surface are attributed to blocked light sources. If infants can use the shadow assumption to perceive the object’s lightness in shadows, they will also be able to detect unnatural lightness changes in shadows. We compared the infants’ looking times to the unnatural and the natural lightness changes in the shadow when an object (duck) goes through the cast shadow. In Experiment 1, we examined whether infants could detect the unnatural lightness changes of the object’s surface in shadows. We created computer-graphic movies of unnatural and natural lightness changes to the duck’s surface. Our results showed that 7- to 8-month-olds but not 5- to 6-month-olds significantly preferred the movie with the unnatural changes in lightness, indicating that only the older infants could detect these changes. In Experiment 2, we confirmed that the infants’ preference was based on the detection of unnatural lightness changes according to the shadow assumption. The natural and the unnatural lightness changes of Experiment 1 were presented without cast shadows. Under these conditions, neither younger nor older infants showed a significant preference. Taken together, the experiments showed that 7- to 8-month-old infants could detect the unnaturalness of a surface’s lightness changes produced by shadows. In conclusion, our findings suggest that 7- to 8-month-old infants can perceive an object’s lightness in shadows by using an assumption that cast shadows dim the surface of an object. PMID:28296912

  5. 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.

  6. 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…

  7. Shadows on a Giant

    NASA Image and Video Library

    2012-07-02

    Saturn rings cast wide shadows on the planet, and the shadow of a moon also graces the gas giant in this scene from NASA Cassini spacecraft. The moon Enceladus is not shown in this view, but it does cast a small, elongated shadow.

  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. 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.

  10. 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

  11. ROSAT Detection of an X-ray Shadow in the 1/4-keV Diffuse Background in the Draco Nebula.

    PubMed

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

    1991-06-14

    The detection by the Roentgen satellite (ROSAT) x-ray telescope of a shadow in the 1/4-kiloelectron volt (C band, 0.1 to 0.284 kiloelectron volt) 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 approximately 600 parsecs); it then follows that there is significant 1/4-kiloelectron volt x-ray emission at a large distance (>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.

  12. 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.

  13. 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.

  14. Wormhole shadows

    NASA Astrophysics Data System (ADS)

    Ohgami, Takayuki; Sakai, Nobuyuki

    2015-06-01

    We propose a new method of detecting Ellis wormholes by use of the images of wormholes surrounded by optically thin dust. First, we derive steady solutions of dust and a more general medium surrounding the wormhole by solving relativistic Euler equations. We find two types of dust solutions: one is a static solution with arbitrary density profile, and the other is a solution of dust which passes into the wormhole and escapes into the other side with constant velocity. Next, solving null geodesic equations and radiation transfer equations, we investigate the images of the wormhole surrounded by dust for the above steady solutions. Because the wormhole spacetime possesses unstable circular orbits of photons, a bright ring appears in the image, just as in Schwarzschild spacetime. This indicates that the appearance of a bright ring solely confirms neither a black hole nor a wormhole. However, we find that the intensity contrast between the inside and the outside of the ring are quite different. Therefore, we could tell the difference between an Ellis wormhole and a black hole with high-resolution very-long-baseline-interferometry observations in the near future.

  15. 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.

  16. 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.

  17. Infant Perception of Incongruent Shapes in Cast Shadows

    PubMed Central

    2015-01-01

    A cast shadow occurs when an object blocks the light from an illumination and projects a dark region onto a surface. Previous studies have reported that adults are slower to identify an object when the object has an incongruent cast shadow than when it has a congruent cast shadow (Castiello, 2001). Here, we used the familiarization-novelty preference procedure to examine whether 5- to 8-month-old infants could detect the relationship between object shapes and cast shadows. In Experiment 1, we examined the infants' ability to detect incongruency between objects and cast shadows. Results showed that 7- to 8-month olds could detect incongruence between the object shapes and the cast shadows, whereas 5- to 6-month olds did not. Yet, our control experiment showed that infants could not detect this incongruence from stimuli in which a white outline had been added to the original cast shadow to decrease the possibility of it being perceived as a cast shadow (Experiment 2). The results of these experiments demonstrate that 7- to 8-month olds responded to the congruence of cast shadows and to consistent contrast polarity between the cast shadow and its background. PMID:28299167

  18. 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…

  19. 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…

  20. Fetal phenotype in a case of partial trisomy 21 and partial monosomy 22 detected prenatally.

    PubMed Central

    Migliorini, A M; Coco, R; De Negrotti, T C; Sanchez, J M; Castineyra, G

    1981-01-01

    Prenatal diagnosis was performed in a woman whose previous pregnancy resulted in a girl with probable Down syndrome who died soon after delivery. The mother was found to be a carrier of a reciprocal balanced translocation between chromosomes 21 and 22, and the fetus was found to have an unbalanced translocation involving chromosomes 21 and 22: 46,XX, -22, +t(21;22)(q22;q11)(21 pter leads to 21q22::22q11 leads to 22qter). Despite partial monosomy for the proximal segment of 22 and trisomy for proximal 21, the fetus did not have gross external abnormalities, but several internal malformations were found. To our knowledge, this is the first time that this unbalanced karyotype has been described. Images PMID:6460105

  1. Highly Sensitive and Quick Detection of Acute Myocardial Infarction Biomarkers Using In2O3 Nanoribbon Biosensors Fabricated Using Shadow Masks.

    PubMed

    Liu, Qingzhou; Aroonyadet, Noppadol; Song, Yan; Wang, Xiaoli; Cao, Xuan; Liu, Yihang; Cong, Sen; Wu, Fanqi; Thompson, Mark E; Zhou, Chongwu

    2016-11-22

    We demonstrate a scalable and facile lithography-free method for fabricating highly uniform and sensitive In2O3 nanoribbon biosensor arrays. Fabrication with shadow masks as the patterning method instead of conventional lithography provides low-cost, time-efficient, and high-throughput In2O3 nanoribbon biosensors without photoresist contamination. Combined with electronic enzyme-linked immunosorbent assay for signal amplification, the In2O3 nanoribbon biosensor arrays are optimized for early, quick, and quantitative detection of cardiac biomarkers in diagnosis of acute myocardial infarction (AMI). Cardiac troponin I (cTnI), creatine kinase MB (CK-MB), and B-type natriuretic peptide (BNP) are commonly associated with heart attack and heart failure and have been selected as the target biomarkers here. Our approach can detect label-free biomarkers for concentrations down to 1 pg/mL (cTnI), 0.1 ng/mL (CK-MB), and 10 pg/mL (BNP), all of which are much lower than clinically relevant cutoff concentrations. The sample collection to result time is only 45 min, and we have further demonstrated the reusability of the sensors. With the demonstrated sensitivity, quick turnaround time, and reusability, the In2O3 nanoribbon biosensors have shown great potential toward clinical tests for early and quick diagnosis of AMI.

  2. Wormhole shadows in rotating dust

    NASA Astrophysics Data System (ADS)

    Ohgami, Takayuki; Sakai, Nobuyuki

    2016-09-01

    As an extension of our previous work, which investigated the shadows of the Ellis wormhole surrounded by nonrotating dust, in this paper we study wormhole shadows in a rotating dust flow. First, we derive steady-state solutions of slowly rotating dust surrounding the wormhole by solving relativistic Euler equations. Solving null geodesic equations and radiation transfer equations, we investigate the images of the wormhole surrounded by dust for the above steady-state solutions. Because the Ellis wormhole spacetime possesses unstable circular orbits of photons, a bright ring appears in the image, just as in Schwarzschild spacetime. The bright ring looks distorted due to rotation. Aside from the bright ring, there appear weakly luminous complex patterns by the emission from the other side of the throat. These structure could be detected by high-resolution very-long-baseline-interferometry observations in the near future.

  3. Detection of binding areas on removable partial denture frameworks.

    PubMed

    Stendahl, C G; Grob, D J

    1979-01-01

    Owing to a multiplicity of errors introduced during impression procedures and fabrication, disclosure of binding areas on the metal framework is an essential part of any removable partial denture service. Disclosure is best accomplished with an indicator that provides a sensitive, thin, even, and opaque coating. The aims of adjustment or relief are to maintain forces along the long axis of abutment teeth and ensure passivity, and in so doing create a more favorable prognosis. Careful consideration and thought must precede any reduction. Experience should contribute greatly in determining the indicated reduction and the accuracy of performing it.

  4. Features and futures: seizure detection in partial epilepsies.

    PubMed

    Han, Yu; Hsin, Yue-Loong; Harnod, Tomor; Liu, Wentai

    2011-10-01

    Many factors underlying basic epileptic conditions determine the characteristics of epileptic seizures and the therapeutic outcome. Diagnosis and treatment rely on the clinical manifestations as well as electroencephalographic (EEG) epileptic activities. This article briefly reviews the fundamentals of the EEG, interictal, and ictal electrical activities of both extracranial and intracranial EEG of partial epilepsies, based on the information obtained from epilepsy patients who have undergone epilepsy surgery. The authors also present the status of their current research, focusing on decomposed seizure sources and the rendered spatial-temporal transitions in focal seizure.

  5. Odysseus Out of Shadow

    NASA Image and Video Library

    2007-02-28

    The Cassini spacecraft stares directly into the great Odysseus impact basin on Tethys. Peaks near the crater center cast long shadows toward the east. The elevated eastern rim of the crater catches sunlight

  6. Shadow and Ringshine

    NASA Image and Video Library

    2010-03-16

    Saturn casts its shadow on the rings in this NASA Cassini spacecraft image that also shows how the rings reflect sunlight onto the dark side of the planet. Here Saturn appears dimly illuminated by this ringshine.

  7. Revealing Shadows 7

    NASA Image and Video Library

    2012-07-31

    These images from NASA Dawn spacecraft, located in asteroid VestaFloronia quadrangle, in Vesta northern hemisphere, demonstrate a special analytical technique, which results in shadowed areas of Vesta surface becoming illuminated.

  8. Revealing Shadows 5

    NASA Image and Video Library

    2012-07-27

    These images from NASA Dawn spacecraft, located in asteroid Vesta Floronia quadrangle, in Vesta northern hemisphere, demonstrate a special analytical technique, which results in shadowed areas of Vesta surface becoming illuminated.

  9. Revealing Shadows 2

    NASA Image and Video Library

    2012-07-24

    These images from NASA Dawn spacecraft, located in asteroid Vesta Oppia quadrangle, in Vesta northern hemisphere, demonstrate a special analytical technique, which results in shadowed areas of Vesta surface becoming illuminated.

  10. Revealing Shadows 4

    NASA Image and Video Library

    2012-07-26

    These images from NASA Dawn spacecraft, located in asteroid Vesta Marcia quadrangle, in Vesta northern hemisphere, demonstrate a special analytical technique, which results in shadowed areas of Vesta surface becoming illuminated.

  11. Revealing Shadows 3

    NASA Image and Video Library

    2012-07-25

    These images from NASA Dawn spacecraft, located in asteroid Vesta Marcia quadrangle, in Vesta northern hemisphere, demonstrate a special analytical technique, which results in shadowed areas of Vesta surface becoming illuminated.

  12. Revealing Shadows 6

    NASA Image and Video Library

    2012-07-30

    These images from NASA Dawn spacecraft, located in asteroid Vesta Caparronia quadrangle, in Vesta northern hemisphere, demonstrate a special analytical technique, which results in shadowed areas of Vesta surface becoming illuminated.

  13. Revealing Shadows 1

    NASA Image and Video Library

    2012-07-23

    These images from NASA Dawn spacecraft, located in Vesta Caparronia quadrangle, in Vesta northern hemisphere, demonstrate a special analytical technique, which results in shadowed areas of Vesta surface becoming illuminated.

  14. Shadowed Craters on Ceres

    NASA Image and Video Library

    2016-07-08

    At the poles of Ceres, scientists have found craters that are permanently in shadow (indicated by blue markings). Such craters are called "cold traps" if they remain below about minus 240 degrees Fahrenheit (minus 151 degrees Celsius). These shadowed craters may have been collecting ice for billions of years because they are so cold. This image was created using data from NASA's Dawn spacecraft. http://photojournal.jpl.nasa.gov/catalog/PIA20696

  15. Auditory Stimulus Detection Partially Depends on Visuospatial Attentional Resources

    PubMed Central

    Murali, Supriya; Sinnett, Scott; König, Peter

    2017-01-01

    Humans’ ability to detect relevant sensory information while being engaged in a demanding task is crucial in daily life. Yet, limited attentional resources restrict information processing. To date, it is still debated whether there are distinct pools of attentional resources for each sensory modality and to what extent the process of multisensory integration is dependent on attentional resources. We addressed these two questions using a dual task paradigm. Specifically, participants performed a multiple object tracking task and a detection task either separately or simultaneously. In the detection task, participants were required to detect visual, auditory, or audiovisual stimuli at varying stimulus intensities that were adjusted using a staircase procedure. We found that tasks significantly interfered. However, the interference was about 50% lower when tasks were performed in separate sensory modalities than in the same sensory modality, suggesting that attentional resources are partly shared. Moreover, we found that perceptual sensitivities were significantly improved for audiovisual stimuli relative to unisensory stimuli regardless of whether attentional resources were diverted to the multiple object tracking task or not. Overall, the present study supports the view that attentional resource allocation in multisensory processing is task-dependent and suggests that multisensory benefits are not dependent on attentional resources. PMID:28203353

  16. Partial discharge detection and analysis in low pressure environments

    NASA Astrophysics Data System (ADS)

    Liu, Xin

    Typical aerospace vehicles (aircraft and spacecraft) experience a wide range of operating pressures during ascending and returning to earth. Compared to the sea-level atmospheric pressure (760 Torr), the pressure at about 60 km altitude is 2 Torr. The performance of the electric power system components of the aerospace vehicles must remain reliable even under such sub-atmospheric operating conditions. It is well known that the dielectric strength of gaseous insulators, while the electrode arrangement remains unchanged, is pressure dependent. Therefore, characterization of the performance and behavior of the electrical insulation in flight vehicles in low-pressure environments is extremely important. Partial discharge testing is one of the practical methods for evaluating the integrity of electrical insulation in aerospace vehicles. This dissertation describes partial discharge (PD) measurements performed mainly with 60 Hz ac energization in air, argon and helium, for pressures between 2 and 760 Torr. Two main electrode arrangements were used. One was a needle-plane electrode arrangement with a Teflon insulating barrier. The other one was a twisted pair of insulated conductors taken from a standard aircraft wiring harness. The measurement results are presented in terms of typical PD current pulse waveforms and waveform analysis for both main electrode arrangements. The evaluation criteria are the waveform polarity, magnitude, shape, rise time, and phase angle (temporal location) relative to the source voltage. Two-variable histograms and statistical averages of the PD parameters are presented. The PD physical mechanisms are analyzed. For PD pattern recognition, both statistical methods (such as discharge parameter dot pattern representation, discharge parameter phase distribution, statistical operator calculations, and PD fingerprint development) and wavelet transform applications are investigated. The main conclusions of the dissertation include: (1) The PD current

  17. Detection of multiple velocity components in partially overlapping emitting regions

    NASA Astrophysics Data System (ADS)

    Mertens, F.; Lobanov, A. P.

    2016-03-01

    Context. Velocity measurements made from multiple-epoch astronomical images of evolving objects with optically thin continuum emission (e.g. as relativistic jets or expanding supernova shells) may be confused as a result of the overlap of semi-transparent features moving at different speeds. Aims: Multi-scale wavelet decomposition can be effectively applied to identify and track such overlapping features, provided that their respective structural responses can be separated over the spatial scales used for the decomposition. Methods: We developed a new method that combines the stacked cross-correlation with the wavelet-based image segmentation and evaluation (WISE) technique of decomposition of two-dimensional structures, to separate and track dominant spatial responses of overlapping evolving features. Results: The method is tested on a set of simulated images of a stratified relativistic jet, demonstrating the robust detection of both the faster spine and the slower sheath speeds. The method is applied to mutliple-epoch images from the MOJAVE survey, revealing two different superluminal streams inside the jet in 3C 273 and the acceleration of the flow in 3C 120. Conclusions: The method can be applied to densely monitored objects with composite structural evolution such as the parsec-scale jet in M 87 or heavily resolved expanding supernova shells.

  18. Auto-Detection of Partial Discharges in Power Cables by Descrete Wavelet Transform

    NASA Astrophysics Data System (ADS)

    Yasuda, Yoh; Hara, Takehisa; Urano, Koji; Chen, Min

    One of the serious problems that may happen in power XLPE cables is destruction of insulator. The best and conventional way to prevent such a crucial accident is generally supposed to ascertain partial corona discharges occurring at small void in organic insulator. However, there are some difficulties to detect those partial discharges because of existence of external noises in detected data, whose patterns are hardly identified at a glance. By the reason of the problem, there have been a number of researches on the way of development to accomplish detecting partial discharges by employing neural network (NN) system, which is widely known as the system for pattern recognition. We have been developing the NN system of the auto-detection for partial discharges, which we actually input numerical data of waveform itself into and obtained appropriate performance from. In this paper, we employed Descrete Wavelet Transform (DWT) to acquire more detailed transformed data in order to put them into the NN system. Employing DWT, we became able to express the waveform data in time-frequency space, and achieved effective detectiton of partial discharges by NN system. We present here the results using DWT analysis for partial discharges and noise signals which we obtained actually. Moreover, we present results out of the NN system which were dealt with those transformed data.

  19. Effective Two-Dimensional Partial Response Maximum Likelihood Detection Scheme for Holographic Data Storage Systems

    NASA Astrophysics Data System (ADS)

    Kong, Gyuyeol; Choi, Sooyong

    2012-08-01

    An effective two-dimensional (2D) partial response maximum likelihood (PRML) detection scheme for holographic data storage (HDS) systems is proposed. The proposed scheme adopts the simplified trellis diagram, uses a priori information, and detects the data in two directions from the previously proposed detection schemes. The simplified trellis diagram which has 4 states and 8 branches yields a dramatic complexity reduction while the simplified 2D PRML detector shows serious performance degradation in the high density HDS channels. To prevent performance degradation, the proposed detector uses a priori information in order to give higher reliability to the branch metric. Furthermore, the proposed scheme detects the data in the vertical and horizontal directions to fully utilize the characteristics of the channel detection with a 2D partial response target. By effective combination of these three techniques, the proposed scheme with a simple structure has more than 2 dB gains compared to the conventional detection schemes.

  20. Shadows constructing a relationship between light and color pigments by physical and mathematical perspectives

    NASA Astrophysics Data System (ADS)

    Yurumezoglu, Kemal; Karabey, Burak; Yigit Koyunkaya, Melike

    2017-03-01

    Full shadows, partial shadows and multilayer shadows are explained based on the phenomenon of the linear dispersion of light. This paper focuses on progressing the understanding of shadows from physical and mathematical perspectives. A significant relationship between light and color pigments is demonstrated with the help of the concept of sets. This integration of physical and mathematical reasoning not only manages an operational approach to the concept of shadows, it also outputs a model that can be used in science, technology, engineering and mathematics (STEM) curricula by providing a concrete and physical example for abstract concept of the empty set.

  1. 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,…

  2. 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)

  3. 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…

  4. 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…

  5. 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…

  6. Bright Spokes, Dark Shadow

    NASA Image and Video Library

    2010-04-06

    Bright spokes and the shadow of a moon grace Saturn B ring in this NASA Cassini spacecraft image. Spokes are radial markings scientists continue to study, and they can be seen here stretching from the far left to upper right of the image.

  7. 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…

  8. 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)

  9. Optical fiber sensor-based detection of partial discharges in power transformers

    NASA Astrophysics Data System (ADS)

    Deng, Jiangdong; Xiao, Hai; Huo, Wei; Luo, Ming; May, Russ; Wang, Anbo; Liu, Yilu

    2001-07-01

    In this paper, a fiber optic acoustic sensor system is designed and tested for on-line detection of the partial discharges inside high voltage power transformers. The fiber optic sensor uses a silica diaphragm and a single mode optical fiber encapsulated in a silica glass tube to form an extrinsic Fabry-Perot interferometer. Test results indicate that the developed fiber optic sensors are capable of detecting the acoustic signals propagating inside the transformer oil with high resolution and high frequency.

  10. 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…

  11. 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…

  12. 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.

  13. 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.

  14. 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.

  15. 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.

  16. 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).

  17. Ceres in Half Shadow

    NASA Image and Video Library

    2015-03-02

    NASA's Dawn spacecraft took these images of dwarf planet Ceres from about 25,000 miles (40,000 kilometers) away on Feb. 25, 2015. Ceres appears half in shadow because of the current position of the spacecraft relative to the dwarf planet and the sun. The resolution is about 2.3 miles (3.7 kilometers) per pixel. http://photojournal.jpl.nasa.gov/catalog/PIA19310

  18. 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…

  19. 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

  20. Detection of open and partially closed surface defects in plates using ultrasonic enhancement

    NASA Astrophysics Data System (ADS)

    Clough, A. R.; Edwards, R. S.

    2013-01-01

    Enhancement of the frequency content of multimodal Lamb waves incident on surface breaking defects has been investigated for use in defect detection and characterization, for different thickness plates with machined defects of varying depth. A fully optical method, using laser ultrasonics, was used to study the enhancement as a function of defect depth when passing either the detection (SLD) or generation (SLS) laser over the defect. Time frequency representations (TFRs) were used to identify the wave modes present at each detection point, and the frequency magnitude of various wave modes was tracked, with an increase in magnitude observed for both scanning laser detection and scanning laser source at the defect. The scanning laser detection enhancement is explained by a superposition of incident waves with those reflected and mode converted from the defect. Scanning laser source enhancement can be explained in terms of several mechanisms; including truncation of the source, the change in geometry at the defect and the change in generation boundary conditions at the defect. The TFR analysis was also applied to samples containing partially closed defects caused by stress corrosion cracking (SCC). Scanning laser detection analysis was shown to be incapable of detecting the defects; however, scanning laser source analysis showed large enhancements over the defect site, illustrating the effectiveness of this method for detection of partially closed cracks.

  1. Soft bilateral filtering volumetric shadows using cube shadow maps

    PubMed Central

    Ali, Hatam H.; Sunar, Mohd Shahrizal; Kolivand, Hoshang

    2017-01-01

    Volumetric shadows often increase the realism of rendered scenes in computer graphics. Typical volumetric shadows techniques do not provide a smooth transition effect in real-time with conservation on crispness of boundaries. This research presents a new technique for generating high quality volumetric shadows by sampling and interpolation. Contrary to conventional ray marching method, which requires extensive time, this proposed technique adopts downsampling in calculating ray marching. Furthermore, light scattering is computed in High Dynamic Range buffer to generate tone mapping. The bilateral interpolation is used along a view rays to smooth transition of volumetric shadows with respect to preserving-edges. In addition, this technique applied a cube shadow map to create multiple shadows. The contribution of this technique isreducing the number of sample points in evaluating light scattering and then introducing bilateral interpolation to improve volumetric shadows. This contribution is done by removing the inherent deficiencies significantly in shadow maps. This technique allows obtaining soft marvelous volumetric shadows, having a good performance and high quality, which show its potential for interactive applications. PMID:28632740

  2. 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…

  3. 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…

  4. Shadow-related concavity-convexity inversions reveal a very basic tolerance for impossible shadows.

    PubMed

    Casati, Roberto

    2014-01-01

    The stimuli traditionally used for demonstrating shadow-related concavity-convexity inversions reveal a very basic tolerance for impossible shadows-namely, self shadows do not induce a visual request for geometrically mandatory cast shadows.

  5. Effective cutoffs for detecting random, partially random, and nonrandom 370-item MMPI-2 short form protocols.

    PubMed

    Pinsoneault, Terry B

    2011-01-01

    The ability of the 370-item short form MMPI-2 (Butcher, Graham, Ben-Porath, Tellegen, Dahlstrom, & Kaemmer, 2001) validity scales to detect random protocols was investigated using samples of 500 nonrandom protocols, 250 half-random protocols, and 250 all-random protocols. The long-form cutoff of VRIN ≥ 80 was unable to detect protocols with either level of randomness. The long-form cutoffs of Fp ≥ 100 or F ≥ 100 were able to detect all-random but not half-random protocols. Alternative cutoffs for VRIN, Fp, and F were investigated and short-form subscales of those scales were developed to improve detection of partially random protocols. An algorithm using alternative cutoffs for the scales and the new subscales was highly effective, detecting almost all of the random protocols as well as the nonrandom protocols. A follow-up cross-validation study was conducted that confirmed the effectiveness of the algorithm.

  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 intensity reduction of ground shadow To deliver better viewing experiences of soccer videos

    NASA Astrophysics Data System (ADS)

    Ko, Jaeseung; Lee, Jaeho; Kim, Changick; Bhaskaran, Vasudev

    2007-09-01

    In this paper, we present a method for reducing the intensity of shadows cast on the ground in outdoor sports videos to provide TV viewers with a better viewing experience. In the case of soccer videos taken by a long-shot camera technique, it is difficult for viewers to discriminate the tiny objects (i.e., soccer ball and player) from the ground shadows. The algorithm proposed in this paper comprises three modules, such as long-shot detection, shadow region extraction and shadow intensity reduction. We detect the shadow region on the ground by using the relationship between Y and U values in YUV color space and then reduce the shadow components depending on the strength of the shadows. Experimental results show that the proposed scheme offers useful tools to provide a more comfortable viewing environment and is amenable to real-time performance even in a software based implementation.

  8. 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

  9. Snake scales, partial exposure, and the Snake Detection Theory: A human event-related potentials study

    PubMed Central

    Van Strien, Jan W.; Isbell, Lynne A.

    2017-01-01

    Studies of event-related potentials in humans have established larger early posterior negativity (EPN) in response to pictures depicting snakes than to pictures depicting other creatures. Ethological research has recently shown that macaques and wild vervet monkeys respond strongly to partially exposed snake models and scale patterns on the snake skin. Here, we examined whether snake skin patterns and partially exposed snakes elicit a larger EPN in humans. In Task 1, we employed pictures with close-ups of snake skins, lizard skins, and bird plumage. In task 2, we employed pictures of partially exposed snakes, lizards, and birds. Participants watched a random rapid serial visual presentation of these pictures. The EPN was scored as the mean activity (225–300 ms after picture onset) at occipital and parieto-occipital electrodes. Consistent with previous studies, and with the Snake Detection Theory, the EPN was significantly larger for snake skin pictures than for lizard skin and bird plumage pictures, and for lizard skin pictures than for bird plumage pictures. Likewise, the EPN was larger for partially exposed snakes than for partially exposed lizards and birds. The results suggest that the EPN snake effect is partly driven by snake skin scale patterns which are otherwise rare in nature. PMID:28387376

  10. Snake scales, partial exposure, and the Snake Detection Theory: A human event-related potentials study.

    PubMed

    Van Strien, Jan W; Isbell, Lynne A

    2017-04-07

    Studies of event-related potentials in humans have established larger early posterior negativity (EPN) in response to pictures depicting snakes than to pictures depicting other creatures. Ethological research has recently shown that macaques and wild vervet monkeys respond strongly to partially exposed snake models and scale patterns on the snake skin. Here, we examined whether snake skin patterns and partially exposed snakes elicit a larger EPN in humans. In Task 1, we employed pictures with close-ups of snake skins, lizard skins, and bird plumage. In task 2, we employed pictures of partially exposed snakes, lizards, and birds. Participants watched a random rapid serial visual presentation of these pictures. The EPN was scored as the mean activity (225-300 ms after picture onset) at occipital and parieto-occipital electrodes. Consistent with previous studies, and with the Snake Detection Theory, the EPN was significantly larger for snake skin pictures than for lizard skin and bird plumage pictures, and for lizard skin pictures than for bird plumage pictures. Likewise, the EPN was larger for partially exposed snakes than for partially exposed lizards and birds. The results suggest that the EPN snake effect is partly driven by snake skin scale patterns which are otherwise rare in nature.

  11. Memory, double, shadow, and evil.

    PubMed

    McNamara, P

    1994-04-01

    In order to examine shadow dynamics the author explores the phenomenology and mythological associations of the 'double' or Doppelgänger. Current Jungian-inspired theories concerning relations of shadow and double are found to be limited because they do not explain (1) the process of personification of the psychic complex which gives rise to the double, (2) the immediate conditions under which doubling occurs, (3) the conditions which lead to the assignment of evil qualities to the double as shadow. The paper seeks to remedy each of the above limitations by redescribing shadow/double phenomena in terms of autonomous memory phenomena, both personal and trans-personal.

  12. Detection, isolation and partial characterization of an immunostimulating glycoprotein from Rhodococcus fascians.

    PubMed

    Butschak, Günter; Karsten, Uwe; Schelhaas, Ute; Ott, Holger; Emmendörffer, Andreas; Niemeyer, Bernd; Helmholz, Heike; Goletz, Steffen

    2006-09-01

    In a search for novel immunostimulating substances we detected that culture supernatants of the gram-positive phytopathogenic bacterium, Rhodococcus fascians, were able to induce cytokine release (TNF(alpha)) from mouse peritoneal macrophages. Monoclonal antibodies were generated against the active principle, and were employed for its isolation and partial characterization as a high molecular (MW>100 kDa) glycoprotein. In addition, methods practicable for its biotechnological preparation and several ELISA variants for its determination were developed.

  13. Fiber Fabry-Perot sensors for detection of partial discharges in power transformers.

    PubMed

    Yu, Bing; Kim, Dae Woong; Deng, Jiangdong; Xiao, Hai; Wang, Anbo

    2003-06-01

    A diaphragm-based interferometric fiberoptic sensor that uses a low-coherence light source was designed and tested for on-line detection of the acoustic waves generated by partial discharges inside high-voltage power transformers. The sensor uses a fused-silica diaphragm and a single-mode optical fiber encapsulated in a fused-silica glass tube to form an extrinsic Fabry-Perot interferometer, which is interrogated by low-coherence light. Test results indicate that these fiber optic acoustic sensors are capable of faithfully detecting acoustic signals propagating inside transformer oil with high sensitivity and wide bandwidth.

  14. Fiber Fabry-Perot Sensors for Detection of Partial Discharges in Power Transformers

    NASA Astrophysics Data System (ADS)

    Yu, Bing; Kim, Dae Woong; Deng, Jiangdong; Xiao, Hai; Wang, Anbo

    2003-06-01

    A diaphragm-based interferometric fiber optic sensor that uses a low-coherence light source was designed and tested for on-line detection of the acoustic waves generated by partial discharges inside high-voltage power transformers. The sensor uses a fused-silica diaphragm and a single-mode optical fiber encapsulated in a fused-silica glass tube to form an extrinsic Fabry-Perot interferometer, which is interrogated by low-coherence light. Test results indicate that these fiber optic acoustic sensors are capable of faithfully detecting acoustic signals propagating inside transformer oil with high sensitivity and wide bandwidth.

  15. 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.

  16. Shadow Realities in Close Relationships.

    ERIC Educational Resources Information Center

    Roseblatt, Paul C.; Wright, Sara E.

    1984-01-01

    Discusses shadow realities, which include unacceptable and threatening information and interpretations that could undermine negotiated relationship reality. Offers theoretical discussion of shadow realities, reasons people avoid them, gains and risks for exploring them, and the therapeutic applications of therapy within a framework that includes…

  17. What colour is a shadow?

    NASA Astrophysics Data System (ADS)

    Hughes, S. W.

    2009-05-01

    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 ImageJ. The average red, green and blue pixel values in a region of interest drawn on a photograph of the paper in sunlight and shadow were 0.3, 0.32, 0.38 and 0.2, 0.3, 0.5 respectively, demonstrating that a shadow under a blue sky has a blue tint. The experiment would be a useful exercise for a science class.

  18. 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

  19. 3D Spatial and Spectral Fusion of Terrestrial Hyperspectral Imagery and Lidar for Hyperspectral Image Shadow Restoration Applied to a Geologic Outcrop

    NASA Astrophysics Data System (ADS)

    Hartzell, P. J.; Glennie, C. L.; Hauser, D. L.; Okyay, U.; Khan, S.; Finnegan, D. C.

    2016-12-01

    Recent advances in remote sensing technology have expanded the acquisition and fusion of active lidar and passive hyperspectral imagery (HSI) from an exclusively airborne technique to terrestrial modalities. This enables high resolution 3D spatial and spectral quantification of vertical geologic structures for applications such as virtual 3D rock outcrop models for hydrocarbon reservoir analog analysis and mineral quantification in open pit mining environments. In contrast to airborne observation geometry, the vertical surfaces observed by horizontal-viewing terrestrial HSI sensors are prone to extensive topography-induced solar shadowing, which leads to reduced pixel classification accuracy or outright removal of shadowed pixels from analysis tasks. Using a precisely calibrated and registered offset cylindrical linear array camera model, we demonstrate the use of 3D lidar data for sub-pixel HSI shadow detection and the restoration of the shadowed pixel spectra via empirical methods that utilize illuminated and shadowed pixels of similar material composition. We further introduce a new HSI shadow restoration technique that leverages collocated backscattered lidar intensity, which is resistant to solar conditions, obtained by projecting the 3D lidar points through the HSI camera model into HSI pixel space. Using ratios derived from the overlapping lidar laser and HSI wavelengths, restored shadow pixel spectra are approximated using a simple scale factor. Simulations of multiple lidar wavelengths, i.e., multi-spectral lidar, indicate the potential for robust HSI spectral restoration that is independent of the complexity and costs associated with rigorous radiometric transfer models, which have yet to be developed for horizontal-viewing terrestrial HSI sensors. The spectral restoration performance is quantified through HSI pixel classification consistency between full sun and partial sun exposures of a single geologic outcrop.

  20. The detection and partial characterization of horse muscle soluble proteins by imnmnoelectrophoresis in agarose gels.

    PubMed

    Casa, C; Tormo, J; Hernandez, P E; Sanz, B

    1985-01-01

    Immunoele ctrophoresis in agarose gels has been used to detect and partially characterize specific protein precipitin hands of horse muscle soluble proteins (HSP), free of cross reactions with the muscle soluble proteins of cow (CSP) and pig (PSP). Of seven precpptin bands obtained by reacting HSP against an anti-HSP antiserum produced by a rabbit, only one was observed to appear by reacting PSP against the same anti-HSP antiserum. This band, and two more, were detected when CSP were analyzed against an anti-HSP antiserum. The other four bands were specific f or the horse muscle soluble proteins. This technique may have the potential to detect the presence of horse meat in unheated ground meat products. Copyright © 1985. Published by Elsevier Ltd.

  1. Ceres Persistent Shadow

    NASA Image and Video Library

    2016-12-15

    This frame from an animation made of images from NASA's Dawn spacecraft shows a crater in the northern polar region of Ceres that is partly in shadow year-round. In several craters like this one, bright water ice deposits have been observed by Dawn's framing camera. This finding suggests that water ice can be stored for significant amounts of time in cold, dark craters on Ceres. Such reservoirs are called "cold traps." At less than minus 260 degrees Fahrenheit (110 Kelvin), they are so chilly that very little of the ice turns into vapor in the course of a billion years. A movie is available at http://photojournal.jpl.nasa.gov/catalog/PIA21082

  2. 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.

  3. 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.

  4. Shadow extraction for urban area based on hyperspherical color sharpening information distortion

    NASA Astrophysics Data System (ADS)

    Guo, Qing; Wang, Qu; Zhang, Hongqun

    2016-10-01

    A shadow extraction method for urban area is presented based on the hyperspherical color transform (HCT) fusion information distortion. We use the near-infrared band of WorldView-2 data to detect the shadow, because the near-infrared band as the long-wave band is more sensitive to shadow comparing to the short-wave band. In the hyperspherical color sharpening (HCS), n input bands are transformed from an n-dimensional Cartesian space to an n-dimensional hyperspherical color space to generate a single intensity component and n-1 angles, and then the intensity component is replaced with the adjusted panchromatic (Pan) image. After HCT, the information amount of the intensity is larger than that of the Pan band. When using the Pan to replace the intensity to get the fused multispectral (MS) image, the information amount is lost. To assess the information distortion of the fusion result, it is found that the shadow is sensitive to the difference index. Hence, the relative difference index is constructed to enhance the shadow information. More specifically, the relative difference index values are made high for shadow area while they are made low for non-shadow area. However, for the original MS image, the digital number values are low for the shadow area while they are high for non-shadow area. Then, by thresholding, the possible shadow area is separated from the non-shadow area. The experimental results show that this shadow extraction method is simple and accurate; not only the shadow of high building but also the little shadows of low trees and between buildings are all detected.

  5. 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.

  6. On the Maximal Invariant Statistic for Adaptive Radar Detection in Partially Homogeneous Disturbance With Persymmetric Covariance

    NASA Astrophysics Data System (ADS)

    Ciuonzo, D.; Orlando, D.; Pallotta, L.

    2016-12-01

    This letter deals with the problem of adaptive signal detection in partially-homogeneous and persymmetric Gaussian disturbance within the framework of invariance theory. First, a suitable group of transformations leaving the problem invariant is introduced and the Maximal Invariant Statistic (MIS) is derived. Then, it is shown that the (Two-step) Generalized-Likelihood Ratio test, Rao and Wald tests can be all expressed in terms of the MIS, thus proving that they all ensure a Constant False-Alarm Rate (CFAR).

  7. Techniques for plotting shadow patterns

    SciTech Connect

    Bainbridge, D.A.

    1982-02-01

    Basic approaches for plotting shadow patterns (summer or winter) are discussed, illustrated, and compared. The solar simulator technique uses floodlights or a moveable table to mimic the sun's path over a model of the building being studied. The drawback is that, for large developments, very small models would have to be built. Graphic solutions (2 types) are described in which: (1) sun angles are used to calculate shadow patterns using trigonometry and (2) drawings are made and shadows are calculated. Examples are given for a house on level ground and on sloping ground. Calculations of shade density are also illustrated. 8 references. (MJJ)

  8. Black Hole Shadows and VSOP-2

    NASA Astrophysics Data System (ADS)

    Takahashi, R.

    2009-08-01

    The radio images in the galactic center with micro-arcsecond resolution will be obtained by the radio interferometer VSOP-2. The apparent sizes of the direct images of the black holes in the nearby massive galaxies such as M87 and Sgr A* also have micro-arcsecond scales, and such black holes will be seen as the shadows in the luminous accreting matter around the black holes. At 43 GHz where VSOP-2 has the highest spatial resolution (38 μarcseconds), the observed images of Sgr A* are smeared out by the interstellar scattering. Therefore, the shadow of Sgr A* will not be resolved at this frequency. In the case of M87, the observed values of the black hole mass and the distance are not precisely determined. The possible minimum angular size of the highest spatial resolution of VSOP-2 corresponds to 12.5 GMBH/c^2 which is smaller than the shadow size of the slowly rotating black hole in the accretion flow with the inner edge of the marginally stable orbit. On the other hand, the possible maximum angular size of the highest spatial resolution of VSOP-2 corresponds to 38.1 GMBH/c^2. In this case, for any value of the black hole spin and the observed inclination angle, the size of the black hole shadow is smaller than the highest spatial resolution of VSOP-2. On the other hand, the observed energy spectrum of the accretion flow in M87 is consistent with the radiatively inefficient accretion flow where the electron temperature is higher than the detection temperature of VSOP-2. This means that the photons from the accretion flow around the black hole in M87 can be detected by VSOP-2. Other related issues are also discussed.

  9. An Investigation of the Likelihood Ratio Test for Detection of Differential Item Functioning under the Partial Credit Model.

    ERIC Educational Resources Information Center

    Kim, Seock-Ho; Cohen, Allan S.; DiStefano, Christine A.; Kim, Sooyeon

    Type I error rates of the likelihood ratio test for the detection of differential item functioning (DIF) in the partial credit model were investigated using simulated data. The partial credit model with four ordered performance levels was used to generate data sets of a 30-item test for samples of 300 and 1,000 simulated examinees. Three different…

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

    PubMed

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

    2015-11-20

    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.

  11. 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

  12. Multichannel optical-fibre heterodyne interferometer for ultrasound detection of partial discharges in power transformers

    NASA Astrophysics Data System (ADS)

    Posada, J. E.; Garcia-Souto, J. A.; Rubio-Serrano, J.

    2013-09-01

    A multichannel interferometric system is proposed for the ultrasonic detection of partial discharges using intrinsic optical fibre sensors that may be immersed in oil. It is based on a heterodyne scheme which drives at least four sensor heads in order to localize the source of the acoustic emissions. Proper design of the sensing head improves its sensitivity through magnification and reaches a compact encapsulated probe able to be installed within power transformers. The optoelectronic implementation and the experimental tests are presented to optimize the resolution (4 channels—4 mrad). In addition, the results of ultrasound measurements at 150 kHz with an optical fibre sensor immersed in water in an acoustic test bench are shown, in which a resolution better than 10 Pa was obtained. Finally, the set-up for three-phase power transformers is demonstrated and characterized to detect and locate the source of acoustic emissions.

  13. A nonlinear quality-related fault detection approach based on modified kernel partial least squares.

    PubMed

    Jiao, Jianfang; Zhao, Ning; Wang, Guang; Yin, Shen

    2017-01-01

    In this paper, a new nonlinear quality-related fault detection method is proposed based on kernel partial least squares (KPLS) model. To deal with the nonlinear characteristics among process variables, the proposed method maps these original variables into feature space in which the linear relationship between kernel matrix and output matrix is realized by means of KPLS. Then the kernel matrix is decomposed into two orthogonal parts by singular value decomposition (SVD) and the statistics for each part are determined appropriately for the purpose of quality-related fault detection. Compared with relevant existing nonlinear approaches, the proposed method has the advantages of simple diagnosis logic and stable performance. A widely used literature example and an industrial process are used for the performance evaluation for the proposed method.

  14. 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…

  15. 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…

  16. 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…

  17. 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…

  18. Detection and Analysis of Partial Reflections of HF Waves from the Lower Ionosphere

    NASA Astrophysics Data System (ADS)

    Erdman, A.; Moore, R. C.

    2016-12-01

    On the afternoon of August 27, 2011, the western half of the High Frequency Active Auroral Research Program's (HAARP's) HF transmitter repeatedly broadcast a low-power (1 kW/Tx), 4.5-MHz, X-mode polarized, 10 microsecond pulse. The HF beam was directed vertically, and the inter-pulse period was 20 milliseconds. HF observations were performed at Oasis (62° 23' 30" N, 145° 9' 03" W) using two crossed 90-foot folded dipoles. Observations clearly indicate the detection of a ground wave and multiple reflections from different sources at F-region altitudes, which is consistent with digisonde measurements at 4.5 MHz. Additional reflections were detected at a virtual altitude of 90-110 km, and we interpret these reflections as partial reflections from the rapid conductivity change at the base of the ionosphere. We compare these observations with the predictions of a new finite-difference time-domain (FDTD) plasma model. The model is a one-dimensional, second-order accurate, cold plasma FDTD model of the ionosphere extending from ground through the lower F-region. The model accounts for a spatially varying plasma frequency, cyclotron frequency, and electron-neutral collision frequency. We discuss the possibility to analyze partial reflections from the base of the ionosphere as a function of frequency to characterize the reflecting plasma.

  19. 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.

  20. Orbital shadowing for 3-flows

    NASA Astrophysics Data System (ADS)

    Gan, Shaobo; Li, Ming

    2017-05-01

    We call that a flow has the orbital shadowing property if for any ε > 0 there is d > 0 such that, for any d-pseudo orbit g (t) there exists an orbit Orb (x) satisfying distH (g (t) ‾ , Orb (x) ‾) < ε. In this paper, we show that the C1-interior of the set of 3-dimensional flows having the orbital shadowing property is contained in the set of Ω-stable 3-flows.

  1. Gullies in Winter Shadow

    NASA Image and Video Library

    2017-03-21

    This is an odd-looking image. It shows gullies during the winter while entirely in the shadow of the crater wall. Illumination comes only from the winter skylight. We acquire such images because gullies on Mars actively form in the winter when there is carbon dioxide frost on the ground, so we image them in the winter, even though not well illuminated, to look for signs of activity. The dark streaks might be signs of current activity, removing the frost, but further analysis is needed. NB: North is down in the cutout, and the terrain slopes towards the bottom of the image. The map is projected here at a scale of 50 centimeters (19.7 inches) per pixel. [The original image scale is 62.3 centimeters (24.5 inches) per pixel (with 2 x 2 binning); objects on the order of 187 centimeters (73.6 inches) across are resolved.] North is up. http://photojournal.jpl.nasa.gov/catalog/PIA21568

  2. 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

  3. 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

    2016-03-24

    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.

  4. The activated partial thromboplastin time of diluted plasma: variability due to the method of fibrin detection.

    PubMed Central

    Johnstone, I B

    1984-01-01

    The purpose of this study was to determine the effects of the dilution of plasma (1/3 in saline) on the kinetics of fibrin generation in the activated partial thromboplastin time (APTT) assay. The diluted APTT is considered to increase the sensitivity of the APTT test however, studies in our laboratory using an electro-optical fibrin detection system failed to show significant differences in APTT values obtained with diluted and undiluted canine plasma. Seventeen plasmas, including plasmas moderately and markedly deficient in intrinsic factor activity were assayed in the undiluted and diluted APTT assay using two methods for fibrin endpoint detection; a visual "tilt-tube" technique and an electro-optical detection system. In the former technique the endpoint was the formation of a visible fibrin web or clot; in the latter procedure the end point was the first detection of a change in optical density of the plasma. Optical density changes during fibrin formation were also recorded ( thrombokinetograms ). The results indicated that the electro-optical fibrin detection system failed to identify a prolongation of the APTT as a result of 1/3 plasma dilution; a prolongation that was consistently observed with the visual fibrin detection technique. Plasma dilution however, did significantly reduce the rate of fibrin production as indicated by the thrombokinetogram profile. It was concluded that the dilution of plasma with saline, as has been used to increase the sensitivity of the APTT assay procedure, has little effect on the time of onset of fibrin formation in a given plasma. The major effect appears to be on the way in which fibrin forms in that the polymerization/crosslinkage events associated with macroscopic fibrin production are delayed. PMID:6722646

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

    NASA Astrophysics Data System (ADS)

    Abdujabbarov, A. A.; Rezzolla, L.; Ahmedov, B. J.

    2015-12-01

    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.

  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. Terrestrial hyperspectral image shadow restoration through fusion with terrestrial lidar

    NASA Astrophysics Data System (ADS)

    Hartzell, Preston J.; Glennie, Craig L.; Finnegan, David C.; Hauser, Darren L.

    2017-05-01

    Recent advances in remote sensing technology have expanded the acquisition and fusion of active lidar and passive hyperspectral imagery (HSI) from exclusively airborne observations to include terrestrial modalities. In contrast to airborne collection geometry, hyperspectral imagery captured from terrestrial cameras is prone to extensive solar shadowing on vertical surfaces leading to reductions in pixel classification accuracies or outright removal of shadowed areas from subsequent analysis tasks. We demonstrate the use of lidar spatial information for sub-pixel HSI shadow detection and the restoration of shadowed pixel spectra via empirical methods that utilize sunlit and shadowed pixels of similar material composition. We examine the effectiveness of radiometrically calibrated lidar intensity in identifying these similar materials in sun and shade conditions and further evaluate a restoration technique that leverages ratios derived from the overlapping lidar laser and HSI wavelengths. Simulations of multiple lidar wavelengths, i.e., multispectral lidar, indicate the potential for HSI spectral restoration that is independent of the complexity and costs associated with rigorous radiometric transfer models, which have yet to be developed for horizontal-viewing terrestrial HSI sensors. The spectral restoration performance of shadowed HSI pixels is quantified for imagery of a geologic outcrop through improvements in spectral shape, spectral scale, and HSI band correlation.

  8. 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).

  9. 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.

  10. Confirmation of a novel siadenovirus species detected in raptors: partial sequence and phylogenetic analysis.

    PubMed

    Kovács, Endre R; Benko, Mária

    2009-03-01

    Partial genome characterisation of a novel adenovirus, found recently in organ samples of multiple species of dead birds of prey, was carried out by sequence analysis of PCR-amplified DNA fragments. The virus, named as raptor adenovirus 1 (RAdV-1), has originally been detected by a nested PCR method with consensus primers targeting the adenoviral DNA polymerase gene. Phylogenetic analysis with the deduced amino acid sequence of the small PCR product has implied a new siadenovirus type present in the samples. Since virus isolation attempts remained unsuccessful, further characterisation of this putative novel siadenovirus was carried out with the use of PCR on the infected organ samples. The DNA sequence of the central genome part of RAdV-1, encompassing nine full (pTP, 52K, pIIIa, III, pVII, pX, pVI, hexon, protease) and two partial (DNA polymerase and DBP) genes and exceeding 12 kb pairs in size, was determined. Phylogenetic tree reconstructions, based on several genes, unambiguously confirmed the preliminary classification of RAdV-1 as a new species within the genus Siadenovirus. Further study of RAdV-1 is of interest since it represents a rare adenovirus genus of yet undetermined host origin.

  11. Detection of upscale-crop and partial manipulation in surveillance video based on sensor pattern noise.

    PubMed

    Hyun, Dai-Kyung; Ryu, Seung-Jin; Lee, Hae-Yeoun; Lee, Heung-Kyu

    2013-09-18

    In many court cases, surveillance videos are used as significant court evidence. As these surveillance videos can easily be forged, it may cause serious social issues, such as convicting an innocent person. Nevertheless, there is little research being done on forgery of surveillance videos. This paper proposes a forensic technique to detect forgeries of surveillance video based on sensor pattern noise (SPN). We exploit the scaling invariance of the minimum average correlation energy Mellin radial harmonic (MACE-MRH) correlation filter to reliably unveil traces of upscaling in videos. By excluding the high-frequency components of the investigated video and adaptively choosing the size of the local search window, the proposed method effectively localizes partially manipulated regions. Empirical evidence from a large database of test videos, including RGB (Red, Green, Blue)/infrared video, dynamic-/static-scene video and compressed video, indicates the superior performance of the proposed method.

  12. Detection of Upscale-Crop and Partial Manipulation in Surveillance Video Based on Sensor Pattern Noise

    PubMed Central

    Hyun, Dai-Kyung; Ryu, Seung-Jin; Lee, Hae-Yeoun; Lee, Heung-Kyu

    2013-01-01

    In many court cases, surveillance videos are used as significant court evidence. As these surveillance videos can easily be forged, it may cause serious social issues, such as convicting an innocent person. Nevertheless, there is little research being done on forgery of surveillance videos. This paper proposes a forensic technique to detect forgeries of surveillance video based on sensor pattern noise (SPN). We exploit the scaling invariance of the minimum average correlation energy Mellin radial harmonic (MACE-MRH) correlation filter to reliably unveil traces of upscaling in videos. By excluding the high-frequency components of the investigated video and adaptively choosing the size of the local search window, the proposed method effectively localizes partially manipulated regions. Empirical evidence from a large database of test videos, including RGB (Red, Green, Blue)/infrared video, dynamic-/static-scene video and compressed video, indicates the superior performance of the proposed method. PMID:24051524

  13. Total and partial cloud amount detection during summer 2005 at Westerland (Sylt, Germany)

    NASA Astrophysics Data System (ADS)

    Schade, N. H.; Macke, A.; Sandmann, H.; Stick, C.

    2009-02-01

    The detection of cloudiness is investigated by means of partial and total cloud amount estimations from pyrgeometer radiation measurements and visible all-sky imager observations. The measurements have been performed in Westerland, a seaside resort on the North Sea island of Sylt, Germany, during summer 2005. An improvement to previous studies on this subject resulting in the first time partial cloud amounts (PCAs), defined as cloud amounts without high clouds calculated from longwave downward radiation (LDR) according to the APCADA algorithm (Dürr and Philipona, 2004), are validated against both human observations from the National Meteorological Servive DWD at the nearby airport of Sylt and digital all-sky imaging. The aim is to establish the APCADA scheme at a coastal midlatitude site for longterm observations of cloud cover and to quantify errors resulting from the different methods of detecting cloudiness. Differences between the resulting total cloud amounts (TCAs), defined as cloud amount for all-cloud situations, derived from the camera images and from human observations are within ±1 octa in 72% and within ±2 octa in 85% of the cases. Compared to human observations, PCA measurements, according to APCADA, underestimate the observed cloud cover in 47% of all cases and the differences are within ±1 octa in 60% and ±2 octa in 74% of all cases. Since high cirrus clouds can not be derived from LDR, separate comparisons for all cases without high clouds have been performed showing an agreement within ±1(2) octa in 73(90)% for PCA and also for camera-derived TCA. For this coastal mid-latitude site under investigation, we find similar though slightly smaller agreements to human observations as reported by Dürr and Philipona (2004). Though limited to daytime, the cloud cover retrievals from the sky imager are not really affected by cirrus clouds and provide a more reliable cloud climatology for all-cloud conditions than APCADA.

  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. 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.

  16. Resolution Of A Shadow Image

    NASA Astrophysics Data System (ADS)

    Edgerton, Harold E.

    1982-02-01

    The 19th century art of shadow imaging, as started by Wedgwood (1803), and as used by William Henry Fox-Talbot (1851) in England, has been revived by using a small-area electronic flash lamp and fine grain film. One immediate application has been the photographic recording of large samples of living plankton. The purpose of this paper is to re-examine the resolution of the shadow system, and to describe some of the strobe light sources that are presently available. Also, a modified method of shadow photography is described where enhanced color images give interesting and, perhaps, important color effects that may be useful in the study of plankton and other semitrans-parent subjects.

  17. Total and partial cloud amount detection during summermonths 2005 at Westerland (Sylt, Germany)

    NASA Astrophysics Data System (ADS)

    Schade, N. H.; Macke, A.; Sandmann, H.; Stick, C.

    2008-07-01

    The detection of cloudiness is investigated by means of partial and total cloud amount estimations from pyrgeometer radiation measurements and all-sky imager observations. The measurements have been performed in Westerland, a seaside resort on the North Sea island of Sylt, Germany, during summer 2005. An improvement to previous studies on this subject results from the fact that for the first time partial cloud amount (PCA), defined as total cloud amounts without high clouds, calculations from longwave downward radiation (LDR) according to the APCADA-Algorithm (Dürr and Philipona, 2004) are validated against both human observations from the German Weather Service DWD at the nearby airport of Sylt and digital all-sky imaging. Differences between the resulting total cloud amounts (TCA's), defined as total cloud amount for all-cloud situations, derived from the camera images and from human observations are within ±1 octa in 72% and within ±2 octa in 85% of the cases. Compared to human observations PCA measurements according to APCADA underestimate the observed cloud cover in 47% of all cases and the differences are within ±1 octa in 60% and ±2 octa in 74% of all cases. Since high cirrus clouds can not be derived from LDR, separate comparisons for all cases without high clouds have been performed showing an agreement within ±1(2) octa in 73(90)% for PCA and also for camera derived TCA. For this coastal mid-latitude site under investigation we find similar though slightly smaller agreements to human observations as reported in Dürr and Philipona (2004). Though limited to day-time the cloud cover retrievals from the sky imager are not much affected by cirrus clouds and provide a more reliable cloud climatology for all-cloud conditions than APCADA.

  18. 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…

  19. 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…

  20. Editing soft shadows in a digital photograph.

    PubMed

    Mohan, Ankit; Tumblin, Jack; Choudhury, Prasun

    2007-01-01

    This technique for modeling, editing, and rendering shadow edges in a photograph or a synthetic image lets users separate the shadow from the rest of the image and make arbitrary adjustments to its position, sharpness, and intensity.

  1. 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.

  2. Optimum study design for detecting imprinting and maternal effects based on partial likelihood.

    PubMed

    Zhang, Fangyuan; Khalili, Abbas; Lin, Shili

    2016-03-01

    Despite spectacular advances in molecular genomic technologies in the past two decades, resources available for genomic studies are still finite and limited, especially for family-based studies. Hence, it is important to consider an optimum study design to maximally utilize limited resources to increase statistical power in family-based studies. A particular question of interest is whether it is more profitable to genotype siblings of probands or to recruit more independent families. Numerous studies have attempted to address this study design issue for simultaneous detection of imprinting and maternal effects, two important epigenetic factors for studying complex diseases. The question is far from settled, however, mainly due to the fact that results and recommendations in the literature are based on anecdotal evidence from limited simulation studies rather than based on rigorous statistical analysis. In this article, we propose a systematic approach to study various designs based on a partial likelihood formulation. We derive the asymptotic properties and obtain formulas for computing the information contents of study designs being considered. Our results show that, for a common disease, recruiting additional siblings is beneficial because both affected and unaffected individuals will be included. However, if a disease is rare, then any additional siblings recruited are most likely to be unaffected, thus contributing little additional information; in such cases, additional families will be a better choice with a fixed amount of resources. Our work thus offers a practical strategy for investigators to select the optimum study design within a case-control family scheme before data collection.

  3. Partial-differential-equation-constrained amplitude-based shape detection in inverse acoustic scattering

    NASA Astrophysics Data System (ADS)

    Na, Seong-Won; Kallivokas, Loukas F.

    2008-03-01

    In this article we discuss a formal framework for casting the inverse problem of detecting the location and shape of an insonified scatterer embedded within a two-dimensional homogeneous acoustic host, in terms of a partial-differential-equation-constrained optimization approach. We seek to satisfy the ensuing Karush-Kuhn-Tucker first-order optimality conditions using boundary integral equations. The treatment of evolving boundary shapes, which arise naturally during the search for the true shape, resides on the use of total derivatives, borrowing from recent work by Bonnet and Guzina [1-4] in elastodynamics. We consider incomplete information collected at stations sparsely spaced at the assumed obstacle’s backscattered region. To improve on the ability of the optimizer to arrive at the global optimum we: (a) favor an amplitude-based misfit functional; and (b) iterate over both the frequency- and wave-direction spaces through a sequence of problems. We report numerical results for sound-hard objects with shapes ranging from circles, to penny- and kite-shaped, including obstacles with arbitrarily shaped non-convex boundaries.

  4. 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…

  5. [Pellegrini-Stieda disease (shadow)].

    PubMed

    Tkebuchava, G I

    1976-02-01

    The Pellegrini-Stied disease (shadow) (calcification periarthritis of the knee) is characterized by the presence of ossification of the medial condyl of the femur. The author's observations of 51 patients (sportsmen) suffering this lesion are described. The methods of conservative and operative treatment and the results obtained are reported.

  6. 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…

  7. 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…

  8. 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.

  9. 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…

  10. 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…

  11. 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.…

  12. 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…

  13. Gait identification from invisible shadows

    NASA Astrophysics Data System (ADS)

    Iwashita, Yumi; Uchino, Koji; Kurazume, Ryo; Stoica, Adrian

    2012-06-01

    This paper introduces a person identification system that uses as input the shadow images of a walking person, as projected by multiple lights(in this application invisible/infrared lights); the system uses a database of examples of shadows images of a number of people who walk. While it is accepted that personal identification has a higher correct classification rate if views from multiple cameras are used, most systems use only one camera, mainly because (i) Installation in real-world environments is easier, less cameras and no need to synchronize cameras, (ii) Computational cost is reduced. In the proposed system, we obtain the advantages of multiple viewpoints with a single camera and additional light sources. More specific, we install multiple infrared lights to project shadows of a subject on the ground and a camera with an infrared transmitting filter mounted in the ceiling inside of a building. Shadow areas, which are projections of one's body on the ground by multiple lights, can be considered as body areas captured from different viewpoints; thus, the proposed system is able to capture multiple projections of the body from a single camera. We explored in other papers the use of sunproduced shadow for identification of people walking freely in the outdoor. In this paper the application scenario is a system installed at the airport in the areas that precedes the immigration checkpoint. Japan already has health monitoring cameras focused on approaching individuals, to determine their health condition; the here described system would also be installed in such a controlled area with restricted walk corridors of walk and controlled lighting. Gait is a remote biometrics and can provide early warning; on another hand it can be used as corroborating evidence in a multi-modal biometrics system. A database of images including shadows for a set of 28 walking people was collected, and the features extracted from shadow areas by affine moment invariants, after which

  14. Performance analysis of a modified moving shadow elimination method developed for indoor scene activity tracking

    NASA Astrophysics Data System (ADS)

    Mitra, Bhargav Kumar; Fiaz, Muhammad Kamran; Kypraios, Ioannis; Birch, Philip; Young, Rupert; Chatwin, Chris

    2008-10-01

    Moving shadow detection is an important step in automated robust surveillance systems in which a dynamic object is to be segmented and tracked. Rejection of the shadow region significantly reduces the erroneous tracking of non-target objects within the scene. A method to eliminate such shadows in indoor video sequences has been developed by the authors. The objective has been met through the use of a pixel-wise shadow search process that utilizes a computational model in the RGB colour space to demarcate the moving shadow regions from the background scene and the foreground objects. However, it has been observed that the robustness and efficiency of the method can be significantly enhanced through the deployment of a binary-mask based shadow search process. This, in turn, calls for the use of a prior foreground object segmentation technique. The authors have also automated a standard foreground object segmentation technique through the deployment of some popular statistical outlier-detection based strategies. The paper analyses the performance i.e. the effectiveness as a shadow detector, discrimination potential, and the processing time of the modified moving shadow elimination method on the basis of some standard evaluation metrics.

  15. A Global Search for Stress Shadows

    NASA Astrophysics Data System (ADS)

    Mallman, E. P.; Parsons, T.

    2004-12-01

    For years scientists have recognized a decrease in seismicity in the regions surrounding the 1857 Fort Tejon and 1906 San Francisco earthquakes in California. This decrease in seismicity has since been correlated with calculated Coulomb stress decrease and termed a stress shadow. Earthquake hazard assessments increasingly incorporate probability perturbations resulting from calculated static stress changes. However, some researchers have questioned the existence of stress shadows when detailed studies of seismicity rates following other earthquakes failed to show correlations between calculated stress decreases and seismicity rate decreases. Regions of decreased seismicity rate are difficult to find compared with rate-increased regions; we thus look for evidence of post-seismic stress rotations, which are easier to detect, require none of the assumptions inherent to static stress calculations, and are a necessary condition for the occurrence of a stress shadow zone. A stress rotation, as determined by comparison of focal mechanisms before and after the mainshock, indicates a changed regional stress state that suppresses events of a certain mechanism and enhances events of a differing mechanism. To independently test the shadow hypothesis, we examined a global catalog of 119 M>7 earthquakes and the events within a 2-degree radius around them that were recorded by the Harvard CMT catalog. We first examined the average mechanism before and after the mainshock, and then compared this with the changes in rate of each of the mechanisms. Of the 119 mainshocks that we identified, 15 showed a rotation of average mechanism following the mainshock that was significant at the 1-sigma level relative to the observed pre-mainshock variability. Of these 15 events, only 2 did not show increases in rate across all mechanisms. That is, only 2 of the 119 show a decrease in at least one mechanism following the mainshock, and also show a significant rotation in mean mechanism. It is

  16. Quantitative Magnetic Resonance Imaging Detects Changes in Meniscal Volume in Vivo After Partial Meniscectomy

    PubMed Central

    Bowers, Megan E.; Tung, Glenn A.; Oksendahl, Heidi L.; Hulstyn, Michael J.; Fadale, Paul D.; Machan, Jason T.; Fleming, Braden C.

    2010-01-01

    Background Quantifying changes in meniscal volume in vivo before and after partial meniscectomy (PM) could help elucidate the mechanisms involved in osteoarthritis development after meniscal injury and its surgical treatment. Purpose/Hypothesis To determine whether quantitative MRI (qMRI) could detect the immediate reduction in meniscal volume created by PM, while ruling out changes in unresected structures. We hypothesized that qMRI would be reliable for determining meniscal volume within the repeated images of unresected menisci. Additionally, we expected no significant difference in volume between the uninjured menisci of the injured knees and the same menisci of the uninjured knees. Study Design Controlled laboratory study. Methods Ten subjects with meniscal tears were evaluated with 3T MRI before and after arthroscopic PM. Manual segmentation was used to create models of the menisci and to determine the pre- and post-operative meniscal volumes for each subject. The responsiveness and reliability of qMRI for determining meniscal volume in vivo were evaluated using these measurements. We expected a decrease in volume of the resected menisci, but not in the uninjured menisci, after surgery. Results The mean pre-operative volume of the injured menisci was significantly greater than the mean post-operative volume (2896±277mm3 vs. 2480±277mm3; p=0.000). There was no significant difference between the mean pre- and post-operative volumes of the uninjured menisci (2687±256mm3 vs. 2694±256mm3; p=1.000). Conclusions Manual segmentation demonstrated a significant reduction in the volume of the surgically resected menisci after PM, but no significant change in the volume of unresected meniscal tissue, indicating that the manual segmentation method is responsive. Clinical Relevance This approach offers a novel, reliable method to study the relationship between the volume of meniscal tissue removed during PM and subsequent patient outcomes during long-term clinical

  17. Quantitative magnetic resonance imaging detects changes in meniscal volume in vivo after partial meniscectomy.

    PubMed

    Bowers, Megan E; Tung, Glenn A; Oksendahl, Heidi L; Hulstyn, Michael J; Fadale, Paul D; Machan, Jason T; Fleming, Braden C

    2010-08-01

    Quantifying changes in meniscal volume in vivo before and after partial meniscectomy (PM) could help elucidate the mechanisms involved in osteoarthritis development after meniscal injury and its surgical treatment. Purpose/ To determine whether quantitative magnetic resonance imaging (qMRI) can detect the immediate reduction in meniscal volume created by PM, while ruling out changes in unresected structures. We hypothesized that qMRI would be reliable for determining meniscal volume within the repeated images of unresected menisci. Additionally, we expected no significant difference in volume between the uninjured menisci of the injured knees and the same menisci of the uninjured knees. Cohort study (Diagnosis); Level of evidence, 2. Ten subjects with meniscal tears were evaluated with 3-T MRI before and after arthroscopic PM. Manual segmentation was used to create models of the menisci and to determine the preoperative and postoperative meniscal volumes for each subject. The responsiveness and reliability of qMRI for determining meniscal volume in vivo were evaluated using these measurements. We expected a decrease in volume of the resected menisci, but not in the uninjured menisci, after surgery. The mean preoperative volume of the injured menisci was significantly greater than the mean postoperative volume (2896 +/- 277 vs 2480 +/- 277 mm(3); P = .000). There was no significant difference between the mean preoperative and postoperative volumes of the uninjured menisci (2687 +/- 256 vs 2694 +/- 256 mm(3); P = 1.000). Manual segmentation demonstrated a significant reduction in the volume of the surgically resected menisci after PM, but no significant change in the volume of unresected meniscal tissue, indicating that the manual segmentation method is responsive. This approach offers a novel, reliable method to study the relationship between the volume of meniscal tissue removed during PM and subsequent patient outcomes during long-term clinical studies.

  18. 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

  19. Signatures of a shadow biosphere.

    PubMed

    Davies, Paul C W; Benner, Steven A; Cleland, Carol E; Lineweaver, Charles H; McKay, Christopher P; Wolfe-Simon, Felisa

    2009-03-01

    Astrobiologists are aware that extraterrestrial life might differ from known life, and considerable thought has been given to possible signatures associated with weird forms of life on other planets. So far, however, very little attention has been paid to the possibility that our own planet might also host communities of weird life. If life arises readily in Earth-like conditions, as many astrobiologists contend, then it may well have formed many times on Earth itself, which raises the question whether one or more shadow biospheres have existed in the past or still exist today. In this paper, we discuss possible signatures of weird life and outline some simple strategies for seeking evidence of a shadow biosphere.

  20. 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.

  1. Spirit Shadow over Laguna Trench

    NASA Technical Reports Server (NTRS)

    2004-01-01

    NASA's Mars Exploration Rover Spirit casts a shadow over the trench that the rover is examining with tools on its robotic arm. Spirit took this image with its front hazard-avoidance camera on Feb. 21, 2004, during the rover's 48th martian day, or sol. It dug the trench with its left front wheel the preceding sol. Plans call for Spirit to finish examining the trench on sol 50.

  2. Segmenting Shadows from synthetic aperture radar imagery using edge-enhanced region growing

    NASA Astrophysics Data System (ADS)

    Power, Gregory J.; Wilson, Kelce S.

    2000-11-01

    An enhanced region-growing approach for segmenting regions is introduced. A region-growing algorithm is merged with stopping criteria based on a robust noise-tolerant edge-detection routine. The region-grow algorithm is then used to segment the shadow region in a Synthetic Aperture Radar (SAR) image. This approach recognizes that SAR phenomenology causes speckle in imagery even to the shadow area due to energy injected from the surrounding clutter and target. The speckled image makes determination of edges a difficult task even for the human observer. This paper outlines the edge-enhanced region grow approach and compares the results to three other segmentation approaches including the region-grow only approach, an automated-threshold approach based on a priori knowledge of the SAR target information, and the manual segmentation approach. The comparison is shown using a tri-metric inter- algorithmic approach. The metrics used to evaluate the segmentation include percent-pixels same (PPS), the partial- directed hausdorff (PDH) metric, and a shape-based metric based on the complex inner product (CIP). Experimental results indicate that the enhanced region-growing technique is a reasonable segmentation for the SAR target image chips obtained from the Moving and Stationary Target Acquisition and Recognition (MSTAR) program.

  3. The shadow price of children.

    PubMed

    Pantoja-hidalgo, C

    1978-06-01

    This article is a review of a thesis entitled "The Shadow Price of Children in Philippine Rural Households" presented by Ms. Teresa Cabanero at the University of the Philippines School of Economics. The thesis assumes that 1) households are units of production and consumption, and 2) children are special commodities which give consumers direct and potential satisfaction. The assumption on which it is based is that childbearing is to a great extent the result of rational economic decisions. Proceeding from this assumption, Cabanero sets out to arrive at an objective measure of the value of children to their parents by computing their "shadow price." This shadow price consists of the costs involved in rearing children both in terms of material goods as well as time spent by parents and older children. In effect, Cabanero has attempted to estimate for a rural community the net costs of rearing children in families of different sizes, incomes, and occupations. The value of the study, according to the reviewer, is its recognition of actual economic costs of children as the major concern of prospective parents. This criterion complements and therefore broadens previously established socioeconomic determinants of fertility, which include such factors as family income, age, education, work status, and place of residence.

  4. Locating the shadow regions in LIDAR data: results on the SHARE 2012 dataset

    NASA Astrophysics Data System (ADS)

    Boyaci, Mustafa; Yuksel, Seniha E.

    2015-05-01

    In hyperspectral imaging, shadowy areas present a major problem as targets in shadow show decreased or no spectral signatures. One way to mitigate this problem is by the fusion of hyperspectral data with LiDAR data; since LiDAR data presents excellent information by providing elevation information, which can then be used to identify the regions of shadow. Although there is a lot of work to detect the shadowy areas, many are restricted to distinct platforms like ARGCIS, ENVI etc. The purpose of this study is to (i) detect the shadow areas and to (ii) give a shadowiness scale in LiDAR data with Matlab in an efficient way. For this work, we designed our Line of Sight (LoS) algorithm that is optimized to run in a Matlab interface. The LoS algorithm uses the sun angles (altitude and azimuth) and elevation of the earth; and marks the pixel as "in shadow" if there lies an object of higher elevation between a given pixel and the sun. This is computed for all pixels in the scene and a shadow map is generated. Further, if a pixel is marked as a shadow area, the algorithm assigns a different darkness level which is inversely proportional to the distance between the current pixel and the object that causes the shadow. With this shadow scale, it is both visually and computationally possible to distinguish the soft shadows from the dark shadows; an important information for hyperspectral imagery. The algorithm has been tested on the SHARE 2012 Avon AM dataset. We also show the effect of the shadowiness scale on the spectral signatures.

  5. A shadow detector for photosynthesis efficiency.

    PubMed

    Liao, Kang-Ling; Jones, Roger D; McCarter, Patrick; Tunc-Ozdemir, Meral; Draper, James A; Elston, Timothy C; Kramer, David; Jones, Alan M

    2017-02-07

    Plants tolerate large variations in the intensity of the light environment by controlling the efficiency of solar to chemical energy conversion. To do this, plants have a mechanism to detect the intensity, duration, and change in light as they experience moving shadows, flickering light, and cloud cover. Sugars are the primary products of CO2 fixation, a metabolic pathway that is rate limited by this solar energy conversion. We propose that sugar is a signal encoding information about the intensity, duration and change in the light environment. We previously showed that the Arabidopsis heterotrimeric G protein complex including its receptor-like Regulator of G signaling protein, AtRGS1, detects both the concentration and the exposure time of sugars (Fu et al., 2014. Cell 156: 1084-1095). This unique property, designated dose-duration reciprocity, is a behavior that emerges from the system architecture / system motif. Here, we show that another property of the signaling system is to detect large changes in light while at the same time, filtering types of fluctuation in light that do not affect photosynthesis efficiency. When AtRGS1 is genetically ablated, photosynthesis efficiency is reduced in a changing- but not a constant-light environment. Mathematical modeling revealed that information about changes in the light environment is encoded in the amount of free AtRGS1 that becomes compartmentalized following stimulation. We propose that this property determines when to adjust photosynthetic efficiency in an environment where light intensity changes abruptly caused by moving shadows on top of a background of light changing gradually from sun rise to sun set and fluctuating light such as that caused by fluttering leaves. Copyright © 2016 Elsevier Ltd. All rights reserved.

  6. 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

  7. Towards a Video Passive Content Fingerprinting Method for Partial-Copy Detection Robust against Non-Simulated Attacks

    PubMed Central

    2016-01-01

    Passive content fingerprinting is widely used for video content identification and monitoring. However, many challenges remain unsolved especially for partial-copies detection. The main challenge is to find the right balance between the computational cost of fingerprint extraction and fingerprint dimension, without compromising detection performance against various attacks (robustness). Fast video detection performance is desirable in several modern applications, for instance, in those where video detection involves the use of large video databases or in applications requiring real-time video detection of partial copies, a process whose difficulty increases when videos suffer severe transformations. In this context, conventional fingerprinting methods are not fully suitable to cope with the attacks and transformations mentioned before, either because the robustness of these methods is not enough or because their execution time is very high, where the time bottleneck is commonly found in the fingerprint extraction and matching operations. Motivated by these issues, in this work we propose a content fingerprinting method based on the extraction of a set of independent binary global and local fingerprints. Although these features are robust against common video transformations, their combination is more discriminant against severe video transformations such as signal processing attacks, geometric transformations and temporal and spatial desynchronization. Additionally, we use an efficient multilevel filtering system accelerating the processes of fingerprint extraction and matching. This multilevel filtering system helps to rapidly identify potential similar video copies upon which the fingerprint process is carried out only, thus saving computational time. We tested with datasets of real copied videos, and the results show how our method outperforms state-of-the-art methods regarding detection scores. Furthermore, the granularity of our method makes it suitable for

  8. 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.

  9. Detection and location of partial discharges in transformer windings using electrical methods

    NASA Astrophysics Data System (ADS)

    McMullan, P. J.

    1983-11-01

    With the increase in power ratings of modern high voltage transformers has come a corresponding interest in the value of partial discharge testing for quality control, design of HV equipment and fault diagnosis. A critical limitation on the development of electrical methods for the location of partial discharges (PD's) in large transformer windings has been the difficulty of pre-determining the changes at transformer terminals due to known disturbances at unique positions within the unit. A particular location and calibration method which is thought to be an improvement on existing techniques is discussed. The new technique is a built-in calibration system having a controlled source of live partial discharges which may be moved up and down the windings under test. The system is intrinsically safe as all the components are insulating materials.

  10. CT detection of fat retention in the bladder after partial nephrectomy.

    PubMed

    Kazaoka, Junichi; Kusakabe, Masashi; Ottomo, Taro; Akahane, Masaaki

    2017-07-01

    This study aimed to investigate the frequency of fat retention in the bladder using postoperative computed tomography (CT) and the associated imaging or clinical findings in patients who underwent renal tumor surgery. We retrospectively reviewed postoperative CT images from 123 patients who underwent surgery for renal tumors (92 patients after partial nephrectomy and 31 after total nephrectomy). Furthermore, we evaluated preoperative tumor characteristics per an established standardized nephrometry scoring system (the R.E.N.A.L Nephrometry Score) for patients with partial nephrectomy. We also investigated whether collecting system repair occurred during surgery. Fat retention in the bladder was found in 5 patients (5.4%) after partial nephrectomy, but was not observed in any patients after total nephrectomy. No fat retention was seen immediately after partial nephrectomy (4-8 days), but occurred 2-15 months after the surgery. Subsequently, intravesical fat retention disappeared in 3 patients (8, 24, and 16 months later), and it persisted from 19-22 months after surgery in the remaining 2 patients. Collecting system repair occurred in 25 patients (27%) with partial nephrectomy. There was no statistically significant association between fat retention in the bladder and intraoperative collecting system repair (p = 0.12). The association with intravesical fat retention was not significant for either tumor size, distance to the collecting system, or the R.E.N.A.L. Nephrometry Score. Fat retention in the bladder after partial nephrectomy can be observed using CT, although it is relatively rare. It is clinically asymptomatic and disappears spontaneously in most cases.

  11. Chronic eosinophilic pneumonia with subpleural curvilinear shadow.

    PubMed

    Kagohashi, Katsunori; Ohara, Gen; Kurishima, Koichi; Kawaguchi, Mio; Nakayama, Hidetsugu; Ishikawa, Hiroichi; Satoh, Hiroaki

    2011-01-01

    We report a rare case of chronic eosinophilic pneumonia with subpleural curvilinear shadow. CT scan showed a patchy consolidation in the bilateral upper lungs. In addition, subpleural curvilinear shadow was found in the bilateral upper lungs. A bronchoalveolar lavage obtained from the right middle lobe showed 25 % eosinophils. Although very rare, we should therefore keep in mind that patients, who have patchy consolidation with areas of subpleural curvilinear shadow in the bilateral upper lungs, may have chronic eosinophilic pneumonia.

  12. The father's shadow/father's body.

    PubMed

    Morgan, D

    1995-09-01

    The shadow of the father plays an important role in a son's ability to live a creatively meaningful life. The mythological basis for the father's shadow is found in the myth of Cronos and his son Zeus. This myth symbolizes a father's body being intimately connected to his son getting in touch with his creative bright shadow. The conclusions reached regarding the importance of the father's shadow are based on research conducted with an ongoing men's group. An early underground phallus dream of Jung is examined, along with the creative work of a patient, both offering evidence of the importance of the body-bond with the father for a son's creative development.

  13. 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.

  14. Three-Dimensional Reconstruction Optical System Using Shadows Triangulation

    NASA Astrophysics Data System (ADS)

    Barba, J. Leiner; Vargas, Q. Lorena; Torres, M. Cesar; Mattos, V. Lorenzo

    2008-04-01

    In this work is developed a three-dimensional reconstruction system using the Shades3D tool of the Matlab® Programming Language and materials of low cost, such as webcam camera, a stick, a weak structured lighting system composed by a desk lamp, and observation plane in which the object is located. The reconstruction is obtained through a triangulation process that is executed after acquiring a sequence of images of the scene with a shadow projected on the object; additionally an image filtering process is done for obtaining only the part of the scene that will be reconstructed. Previously, it is necessary to develop a calibration process for determining the internal camera geometric and optical characteristics (intrinsic parameters), and the 3D position and orientation of the camera frame relative to a certain world coordinate system (extrinsic parameters). The lamp and the stick are used to produce a shadow which scans the object; in this technique, it is not necessary to know the position of the light source, instead the triangulation is obtained using shadow plane produced by intersection between the stick and the illumination pattern. The webcam camera captures all images with the shadow scanning the object, and Shades3D tool processes all information taking into account captured images and calibration parameters. Likewise, this technique is evaluated in the reconstruction of parts of the human body and its application in the detection of external abnormalities and elaboration of prosthesis or implant.

  15. Dark matter trapping by stellar bars: the shadow bar

    NASA Astrophysics Data System (ADS)

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

    2016-12-01

    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 3 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.

  16. Shadows and spirals in the protoplanetary disk HD 100453

    NASA Astrophysics Data System (ADS)

    Benisty, M.; Stolker, T.; Pohl, A.; de Boer, J.; Lesur, G.; Dominik, C.; Dullemond, C. P.; Langlois, M.; Min, M.; Wagner, K.; Henning, T.; Juhasz, A.; Pinilla, P.; Facchini, S.; Apai, D.; van Boekel, R.; Garufi, A.; Ginski, C.; Ménard, F.; Pinte, C.; Quanz, S. P.; Zurlo, A.; Boccaletti, A.; Bonnefoy, M.; Beuzit, J. L.; Chauvin, G.; Cudel, M.; Desidera, S.; Feldt, M.; Fontanive, C.; Gratton, R.; Kasper, M.; Lagrange, A.-M.; LeCoroller, H.; Mouillet, D.; Mesa, D.; Sissa, E.; Vigan, A.; Antichi, J.; Buey, T.; Fusco, T.; Gisler, D.; Llored, M.; Magnard, Y.; Moeller-Nilsson, O.; Pragt, J.; Roelfsema, R.; Sauvage, J.-F.; Wildi, F.

    2017-01-01

    Context. Understanding the diversity of planets requires studying the morphology and physical conditions in the protoplanetary disks in which they form. Aims: We aim to study the structure of the 10 Myr old protoplanetary disk HD 100453, to detect features that can trace disk evolution and to understand the mechanisms that drive these features. Methods: We observed HD 100453 in polarized scattered light with VLT/SPHERE at optical (0.6 μm, 0.8 μm) and near-infrared (1.2 μm) wavelengths, reaching an angular resolution of 0.02'', and an inner working angle of 0.09''. Results: We spatially resolve the disk around HD 100453, and detect polarized scattered light up to 0.42'' ( 48 au). We detect a cavity, a rim with azimuthal brightness variations at an inclination of 38° with respect to our line of sight, two shadows and two symmetric spiral arms. The spiral arms originate near the location of the shadows, close to the semi major axis. We detect a faint feature in the SW that can be interpreted as the scattering surface of the bottom side of the disk, if the disk is tidally truncated by the M-dwarf companion currently seen at a projected distance of 119 au. We construct a radiative transfer model that accounts for the main characteristics of the features with an inner and outer disk misaligned by 72°. The azimuthal brightness variations along the rim are well reproduced with the scattering phase function of the model. While spirals can be triggered by the tidal interaction with the companion, the close proximity of the spirals to the shadows suggests that the shadows could also play a role. The change in stellar illumination along the rim induces an azimuthal variation of the scale height that can contribute to the brightness variations. Conclusions: Dark regions in polarized images of transition disks are now detected in a handful of disks and often interpreted as shadows due to a misaligned inner disk. However, the origin of such a misalignment in HD 100453, and

  17. 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.

  18. Shadows Along the Spiritual Pathway.

    PubMed

    Humphrey, Caroline

    2015-12-01

    Contemporary spirituality discourses tend to assume that a canopy of light and love overarches all spiritual pathways. Unfortunately, the dark side of humanity cannot be spirited away so easily, and aberrations of personal spiritual development, interpersonal spiritual relationships and new spiritual movements can often be traced to the denial, repression and return of our dark side. Transpersonal psychology offers a way of approaching, reframing and redeeming the unconscious depths of our psyche, with its metaphors of shadows and daimons on the one hand, and its therapeutic practices for symbolically containing and transcending polarities on the other. In its absence, any spirituality which eulogises holistic growth is likely to engender the reverse effect.

  19. Limited diagnostic accuracy of magnetic resonance imaging and clinical tests for detecting partial-thickness tears of the rotator cuff.

    PubMed

    Brockmeyer, Matthias; Schmitt, Cornelia; Haupert, Alexander; Kohn, Dieter; Lorbach, Olaf

    2017-09-23

    The reliable diagnosis of partial-thickness tears of the rotator cuff is still elusive in clinical practise. Therefore, the purpose of the study was to determine the diagnostic accuracy of MR imaging and clinical tests for detecting partial-thickness tears of the rotator cuff as well as the combination of these parameters. 334 consecutive shoulder arthroscopies for rotator cuff pathologies performed during the time period between 2010 and 2012 were analyzed retrospectively for the findings of common clinical signs for rotator cuff lesions and preoperative MR imaging. These were compared with the intraoperative arthroscopic findings as "gold standard". The reports of the MR imaging were evaluated with regard to the integrity of the rotator cuff. The Ellman Classification was used to define partial-thickness tears of the rotator cuff in accordance with the arthroscopic findings. Descriptive statistics, sensitivity, specificity, positive and negative predictive value were calculated. MR imaging showed 80 partial-thickness and 70 full-thickness tears of the rotator cuff. The arthroscopic examination confirmed 64 partial-thickness tears of which 52 needed debridement or refixation of the rotator cuff. Sensitivity for MR imaging to identify partial-thickness tears was 51.6%, specificity 77.2%, positive predictive value 41.3% and negative predictive value 83.7%. For the Jobe-test, sensitivity was 64.1%, specificity 43.2%, positive predictive value 25.9% and negative predictive value 79.5%. Sensitivity for the Impingement-sign was 76.7%, specificity 46.6%, positive predictive value 30.8% and negative predictive value 86.5%. For the combination of MR imaging, Jobe-test and Impingement-sign sensitivity was 46.9%, specificity 85.4%, positive predictive value 50% and negative predictive value 83.8%. The diagnostic accuracy of MR imaging and clinical tests (Jobe-test and Impingement-sign) alone is limited for detecting partial-thickness tears of the rotator cuff. Additionally

  20. 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

  1. Quantitative encoding of a partial agonist effect on individual opioid receptors by multi-site phosphorylation and threshold detection

    PubMed Central

    Lau, Elaine K.; Trester-Zedlitz, Michelle; Trinidad, Jonathan C.; Kotowski, Sarah J.; Krutchinsky, Andrew N.; Burlingame, Alma L.; von Zastrow, Mark

    2013-01-01

    Many drugs act as partial agonists of seven-transmembrane signaling receptors when compared to endogenous ligands. Partial agonism is well described as a 'macroscopic' property manifest at the level of physiological systems or cell populations, but it is not known whether partial agonists encode discrete regulatory information at the 'microscopic' level of individual receptors. We addressed this question by focusing on morphine, a partial agonist drug for µ-type opioid peptide receptors, and combining quantitative mass spectrometry with cell biological analysis to investigate morphine's reduced efficacy for promoting receptor endocytosis when compared to a peptide full agonist. We show that these chemically distinct ligands produce a complex, and qualitatively similar mixture of phosphorylated opioid receptor forms in intact cells. Quantitatively, however, the agonists promote markedly disproportional production of multi-site phosphorylation involving a specific Ser/Thr motif, whose modification at more than one residue is essential for efficient recruitment of the adaptor protein β-arrestin to clathrin-coated pits that mediate subsequent endocytosis of MORs. These results reveal quantitative encoding of agonist-selective endocytosis at the level of individual opioid receptors, based on the conserved biochemical principles of multi-site phosphorylation and threshold detection. PMID:21868358

  2. A two-dimensional partial response maximum likelihood detection scheme for misalignment compensation in holographic data storage systems

    NASA Astrophysics Data System (ADS)

    Kong, Gyuyeol; Choi, Sooyong

    2017-09-01

    A two-dimensional (2D) partial response maximum likelihood (PRML) detection scheme for misalignment compensation for holographic data storage systems is proposed. In the proposed detection scheme, a misalignment estimator and a predetermined table are added to the conventional 2D PRML scheme to estimate and reflect the effect of misalignment in the vertical and horizontal directions, respectively. In the vertical detection, the misalignment estimator located behind the vertical 2D equalizer and one-dimensional PRML detector estimates the misalignment by the adaptive least-mean-square algorithm (LMS). To improve the estimation accuracy, the misalignment is estimated iteratively by modifying the vertical equalizer coefficients reflecting the estimated misalignment. By considering the estimated misalignment, the vertical 2D equalizer coefficients, horizontal 2D equalizer coefficients, and 2D partial response (PR) target are selected among the predetermined table. In the predetermined table, the vertical and horizontal 2D equalizer coefficients for various misalignments were previously computed on the basis of the misalignment and 2D PR target by the LMS. By employing the horizontal 2D equalizer coefficients and 2D PR target reflecting the misalignment in the horizontal detection, the effect of misalignment is effectively mitigated. Simulation results show that the proposed scheme has more than 3 dB gains than the conventional scheme in the 10% misalignment in the horizontal and vertical directions.

  3. [Detection of masticatory muscle in bilateral distal-extension partially edentulous patients before and after prosthetic rehabilitation by surface electromyography].

    PubMed

    Yu, Chu-Hua; Chen, Yu-Qin; Zhang, Fu-Qiang

    2006-10-01

    To analyze the difference of masticatory muscle in bilateral distal-extension partially edentulous patients before and after prosthetic rehabilitation by surface electromyography. Twenty-seven bilateral distal-extension partially edentulous patients were randomly selected, and be detected before and after prosthetic rehabilitation by surface electromyography. During the detection, the amplitudes of the anterior temporalis and masseter muscle were registered. Using them, the asymmetry index of total, asymmetry index of the masseter, asymmetry index of the anterior temporalis and mastication index were calculated. Student's t test was used to analyze the results. The asymmetry index of total and asymmetry index of the masseter in group of one month after prosthetic rehabilitation increased significantly than that in the group before prosthetic rehabilitation (P < 0.05); The asymmetry index of total and asymmetry index of the anterior temporalis in group of three or six months after prosthetic rehabilitation decreased significantly than that in the group before prosthetic rehabilitation (P < 0.05); The mastication index decreased gradually after prosthetic rehabilitation, the difference was also be significant between group of three or six months after prosthetic rehabilitation and group before prosthetic rehabilitation (P < 0.05). After prosthetic rehabilitation, the equation and reservation of muscle's energy in bilateral distal-extension partially edentulous patients were significantly better than before. Whereas it costed more than three months for patients to adapt the dentures.

  4. Mapping and characterization of non-polar permanent shadows on the lunar surface

    NASA Astrophysics Data System (ADS)

    McGovern, J. Andrew; Bussey, D. Benjamin; Greenhagen, Benjamin T.; Paige, David A.; Cahill, Joshua T. S.; Spudis, Paul D.

    2013-03-01

    We present the first globally complete inventory of permanent shadows on the lunar surface that are detectable with the current global instrument datasets, including discovery of regions with persistent shadows over geologic time periods as close to the equator as ±58° of latitude. These results were obtained through application of a ray tracing technique to the latest global topographic datasets from the Lunar Reconnaissance Orbiter. Our analysis reveals that 13,361 km2 of surface in the northern hemisphere and 17,698 km2 in the southern hemisphere are permanently shadowed. We present maps showing the locations of all the permanent shadows detectable using these datasets then turn our focus toward the permanent shadows farthest from the poles. Each permanent shadow on the equator side of ±65° of latitude is shown in detail. Surface brightness temperature data derived from the Diviner mid-infrared radiometer on board the Lunar Reconnaissance Orbiter have been analyzed for four of these locations and found to have mid-day temperatures 75-120 K less than nearby comparison locations that experience direct daytime illumination. In some cases the permanently shadowed locations have nighttime temperatures 10-25 K lower than surroundings. The temperature results support our finding that these non-polar craters are permanently shadowed. The surface brightness temperature results also raise interesting questions about their ability to cold trap volatiles. Discovery of these non-polar permanently shadowed regions increases possible locations of water resources and high priority exploration targets on the Moon.

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

    USDA-ARS?s Scientific Manuscript database

    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. ...

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

    USDA-ARS?s Scientific Manuscript database

    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, ...

  7. 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.; Chen, Y. F.; Li, Y. R.

    2017-04-01

    An all-fiber graphene oxide (GO) based 'FRET on Fiber' concept is proposed and applied in biochemical detections. This method is of both good selectivity and high sensitivity, with detection limits of 1.2 nM, 1.3 μM and 1 pM, for metal ion, dopamine and single-stranded DNA (ssDNA), respectively.

  8. Exploring the World through Job Shadowing

    ERIC Educational Resources Information Center

    Reese, Susan

    2005-01-01

    On Groundhog Day, more than one million young people will have an opportunity to explore their possible future careers, according to the Job Shadow Coalition. However, with its components of career exploration, school-to-career training and cooperative learning experiences, career and technical education programs may include job shadowing for…

  9. 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…

  10. 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…

  11. 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.

  12. 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.

  13. [Test for detection of activated partial thromboplastin time using ellagic acid].

    PubMed

    Berkovskiĭ, A L; Sergeeva, E V; Kachalova, N D; Prostakova, T M; Kozlov, A A

    1999-06-01

    A simple and sensitive method for estimation of activated partial thromboplastin time (APTT) is developed, making use a complex reagent containing the activator (plant phospholipids) and contact factor (ellagic acid). The test requires additionally only 0.025 M CaCl2. The test is more sensitive to the presence of heparin in the blood and to insufficiency of blood clotting factors VIII and IX than the reagents containing insoluble substances (kaolin and animal phosphatides). Addition of soluble ellagic acid into reagent for APTT estimation allows studies on optic coagulometers.

  14. 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.

  15. 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.

  16. 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.

  17. 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.

  18. 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

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

    PubMed Central

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

    2013-01-01

    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. PMID:24247657

  20. Detection of Multiple Cracks on a Partially Obstructed Plate Structure Following the Probabilistic Approach

    NASA Astrophysics Data System (ADS)

    Yin, T.; Lam, H. F.; Chow, H. M.

    2010-05-01

    This paper addresses the problem of detecting multiple cracks on thin plates utilizing measured dynamic responses from only a few points on the target plate. Most existing model-based methods in the literature focus on the detection of single-crack or multi-crack with given crack number on beams. Only very limited number of researches have been carried out for the detection of multiple cracks for plate-type structures following the model-based method. There are two phase contained in the proposed crack detection methodology. The number of cracks is first identified by adopting the Bayesian model class selection method in the first stage. After that, the posterior (updated) probability density function (PDF) of the crack parameters, such as crack locations, lengths and depths are identified in the second phase following the Bayesian statistical identification framework. Very encouraging results are obtained for the case studies showing that the proposed methodology can correctly identify the number of cracks, the corresponding crack parameters and their associated uncertainties. Some useful discussions are also made through the case studies.

  1. Two-wavelength quadrature multipoint detection of partial discharge in power transformers using fiber Fabry-Perot acoustic sensors

    NASA Astrophysics Data System (ADS)

    Dong, Bo; Han, Ming; Wang, Anbo

    2012-06-01

    A reliable and low-cost two-wavelength quadrature interrogating method has been developed to demodulate optical signals from diaphragm-based Fabry-Perot interferometric fiber optic sensors for multipoint partial discharge detection in power transformers. Commercial available fused-silica parts (a wafer, a fiber ferrule, and a mating sleeve) and a cleaved optical single mode fiber were bonded together to form an extrinsic Fabry-Perot acoustic sensor. Two lasers with center wavelengths separated by a quarter of the period of sensor interference fringes were used to probe acousticwave- induced diaphragm vibration. A coarse wavelength-division multiplexing (CWDM) add/drop multiplexer was used to separate the reflected two wavelengths before two photo detectors. Optical couplers were used to distribute mixed laser light to each sensor-detector module for multiplexing purpose. Sensor structure, detection system design and experiment results are presented.

  2. On the removal of shadows from images.

    PubMed

    Finlayson, Graham D; Hordley, Steven D; Lu, Cheng; Drew, Mark S

    2006-01-01

    This paper is concerned with the derivation of a progression of shadow-free image representations. First, we show that adopting certain assumptions about lights and cameras leads to a 1D, gray-scale image representation which is illuminant invariant at each image pixel. We show that as a consequence, images represented in this form are shadow-free. We then extend this 1D representation to an equivalent 2D, chromaticity representation. We show that in this 2D representation, it is possible to relight all the image pixels in the same way, effectively deriving a 2D image representation which is additionally shadow-free. Finally, we show how to recover a 3D, full color shadow-free image representation by first (with the help of the 2D representation) identifying shadow edges. We then remove shadow edges from the edge-map of the original image by edge in-painting and we propose a method to reintegrate this thresholded edge map, thus deriving the sought-after 3D shadow-free image.

  3. 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

  4. Shadow Areas Robust Matching Among Image Sequence in Planetary Landing

    NASA Astrophysics Data System (ADS)

    Ruoyan, Wei; Xiaogang, Ruan; Naigong, Yu; Xiaoqing, Zhu; Jia, Lin

    2017-01-01

    In this paper, an approach for robust matching shadow areas in autonomous visual navigation and planetary landing is proposed. The approach begins with detecting shadow areas, which are extracted by Maximally Stable Extremal Regions (MSER). Then, an affine normalization algorithm is applied to normalize the areas. Thirdly, a descriptor called Multiple Angles-SIFT (MA-SIFT) that coming from SIFT is proposed, the descriptor can extract more features of an area. Finally, for eliminating the influence of outliers, a method of improved RANSAC based on Skinner Operation Condition is proposed to extract inliers. At last, series of experiments are conducted to test the performance of the approach this paper proposed, the results show that the approach can maintain the matching accuracy at a high level even the differences among the images are obvious with no attitude measurements supplied.

  5. Stress shadows - a controversial topic

    NASA Astrophysics Data System (ADS)

    Lasocki, Stanislaw; Karakostas, Vassilis G.; Papadimitriou, Eletheria E.; Orlecka-Sikora, Beata

    2010-05-01

    The spatial correlation between the positive Coulomb stress changes and the subsequent seismic activity has been firmly confirmed in many recent studies. If, however, the static stress transfer is a consistent expression of interaction between earthquakes one should also observe a decrease of the activity in the zones of negative stress changes. Instead, the existence of stress shadows is poorly evidenced and may be questioned. We tested the influence of the static stress changes associated with the coseismic slip of the 1995 Mw6.5 Kozani-Grevena (Greece) earthquake on locations of its aftershocks. The study was based on a detailed slip model for the main shock and accurate locations and reliable fault plane solutions of an adequate number of the aftershocks. We developed a statistical testing method, which tested whether the proportions of aftershocks located inside areas determined by a selected criterion on the static stress change could be attained if there were no effect of the stress change due to the main shock on aftershock locations. The areas of stress change were determined at the focus of every aftershock. The distribution of test statistic was constructed with the use of a two-dimensional nonparametric, kernel density estimator of the reference epicenter distribution. The tests highly confidently indicated a rise in probability to locate aftershocks inside areas of positive static stress change, which supported the hypothesis on the triggering effect in these areas. Furthermore, it was evidenced that a larger stress increase caused a stronger triggering effect. The analysis, however, did not evidence the existence of stress shadows inside areas of negative stress change. Contrary to expectations, the tests indicated a significant increase of the probability of event location in the areas of a stress decrease of more than or equal to 5.0 and 10.0 bar. It turned out that for areas of larger absolute stress change this probability increased regardless of

  6. 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.

  7. Use of a modified activated partial thromboplastin time to detect lupus anticoagulants.

    PubMed

    Cloherty, T; Golden, E A; Lind, S E

    1996-07-15

    Laboratory evidence for the presence of lupus anticoagulants (LAs) is sought when patients experience thrombotic events or when coagulation assays are abnormal. Although a number of tests for LAs have been proposed, none detect all LAs, and laboratories may be confronted with the need to perform more than one test to confirm a suspected LA. Recently, a modification of the aPTT, performed by varying the initial time of incubation of the aPTT reagent with the patient's plasma, was reported to detect LAs. The difference in clotting times when plasma is subjected to a 1- or 10- minute incubation (called here the "Delta one minus ten" or DOT) using a particular micronized silica-based aPTT reagent was shown to provide good discrimination between normal and LA plasmas. Because of the low cost of this test and its relative ease of performance, we attempted to replicate the results of this test using previously characterized LA plasmas. The DOT of 23 normal plasmas was 5.1 +/- 2.1 seconds, with a range of 0.5 - 9.3 seconds. The DOT of 20 of 34 LA samples tested (59%) was > 11 seconds. The DOT was abnormal in 8 of 22 (36%) samples diagnosed with a dilute Russell's viper venom time. It was abnormal in 12 of 12 patients diagnosed by other criteria, prior to the use of the dilute Russell's viper venom time. The DOT performed with a kaolin or ellagic acid-based aPTT reagent failed to discriminate normal from LA plasma. We conclude that the DOT performed with a specific silica-based reagent is an apparently simple and moderately sensitive test for detecting the lupus anticoagulant that deserves further evaluation.

  8. 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)

  9. 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)

  10. Shadowing: An Innovative Perceptual-Motor Experience for Young Children.

    ERIC Educational Resources Information Center

    Crawford, Connie M.

    In 1988, 59 Kindergarten students were studied to determine the effect of "shadowing" on perceptual-motor learning. Shadowing is a method whereby the use of one's shadow provides visual feedback. The method developed from observing children's natural curiosity in creating shadows. Illuminated by sunlight outdoors or overhead projectors…

  11. Detectability improvement of early sign of acute stroke on brain CT images using an adaptive partial smoothing filter

    NASA Astrophysics Data System (ADS)

    Lee, Yongbum; Takahashi, Noriyuki; Tsai, Du-Yih; Fujita, Hiroshi

    2006-03-01

    Detection of early infarct signs on non-enhanced CT is mandatory in patients with acute ischemic stroke. We present a method for improving the detectability of early infarct signs of acute ischemic stroke. This approach is considered as the first step for computer-aided diagnosis in acute ischemic stroke. Obscuration of the gray-white matter interface at the lentiform nucleus or the insular ribbon has been an important early infarct sign, which affects decisions on thrombolytic therapy. However, its detection is difficult, since the early infarct sign is subtle hypoattenuation. In order to improve the detectability of the early infarct sign, an image processing being able to reduce local noise with edges preserved is desirable. To cope with this issue, we devised an adaptive partial smoothing filter (APSF). Because the APSF can markedly improve the visibility of the normal gray-white matter interface, the detection of conspicuity of obscuration of gray-white matter interface due to hypoattenuation could be increased. The APSF is a specifically designed filter used to perform local smoothing using a variable filter size determined by the distribution of pixel values of edges in the region of interest. By adjusting four parameters of the APSF, an optimal condition for image enhancement can be obtained. In order to determine a major one of the parameters, preliminary simulation was performed by using composite images simulated the gray-white matter. The APSF based on preliminary simulation was applied to several clinical CT scans in hyperacute stroke patients. The results showed that the detectability of early infarct signs is much improved.

  12. The Spirit of Chinese Shadow Puppet Theater.

    ERIC Educational Resources Information Center

    Okada, Kyle; Olivier-Hirasawa, Susan

    2002-01-01

    Presents a project where fourth- and fifth-grade students created Chinese shadow puppets, designed scenery for puppet theater, built the theater, wrote plays, and put on performances in a Chinese theater festival. Lists a collection of resources. (CMK)

  13. Removing shadows from Google Earth satellite images

    NASA Astrophysics Data System (ADS)

    Guo, Jianhong; Gong, Peng; Liang, Lu

    2007-06-01

    June 2005, Google has released its geographic search tool "Google earth", a new application that combines local search with satellite images and maps from around the globe. It is designed to make every person owned a computer easily "fly" to aerial views of many locations on the planet. However, just as ordinary satellite images, there inevitably exist shadows in it, made some ground objects obscure, even unidentifiable. According to the basic thinking of Radiative Transfer Theory, this paper built a image shadow removal model, which using the Radiative Transfer Theory combined with preknowledge to compensate the lost shadow area information. The results shows: shadows in images were successfully removed and the target objects were returned to their original scenes.

  14. Shadow of noncommutative geometry inspired black hole

    SciTech Connect

    Wei, Shao-Wen; Cheng, Peng; Zhong, Yi; Zhou, Xiang-Nan E-mail: pcheng14@lzu.edu.cn E-mail: zhouxn10@lzu.edu.cn

    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/M{sub 0} with M{sub 0} black hole mass and inclination angle i, the dimensionless noncommutative parameter √θ/M{sub 0} 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 √θ/M{sub 0}, while the distortion increases with it. Compared to the Kerr black hole, the parameter √θ/M{sub 0} 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.

  15. Shadow Imaging of Geosynchronous Satellites: Simulation, Image Reconstruction, and Shadow Prediction

    NASA Astrophysics Data System (ADS)

    Douglas, D.; Hunt, B.; Sheppard, D.

    2016-09-01

    Shadow imaging is a technique to obtain highly resolved silhouettes of resident space objects (RSOs) which would otherwise be unattainable using conventional terrestrial based imaging approaches. This is done by post processing the measured irradiance pattern (shadow) cast onto the Earth as the RSO occults a star. The research presented here focuses on shadow imaging of geosynchronous (GEO) satellites with near stationary orbits approximately 36,000 km from the Earth. Shadows pertaining to a set of diverse observing scenarios are simulated and used as inputs to a Fresnel based phase retrieval algorithm. Spatial resolution limits are evaluated and correlated to signal to noise (SNR) metrics. Resolvable feature sizes of less than 1 m are shown to be readily achievable using foreseeable observing scenarios. The development of a shadow prediction capability is outlined with initial output indicating that there are, on average, over 1000 shadows on the Earth on any given time from a single GEO satellite for stars brighter than mv=10. Shadow ground track uncertainties are correlated to stellar astrometric errors. Global and localized shadow track maps are presented demonstrating a high feasibility for future shadow collections.

  16. Shadow imaging of geosynchronous satellites: simulation, image reconstruction, and shadow prediction

    NASA Astrophysics Data System (ADS)

    Douglas, Dennis M.; Hunt, Bobby R.; Sheppard, David G.

    2016-09-01

    Shadow imaging is a technique to obtain highly resolved silhouettes of resident space objects (RSOs) which would otherwise be unattainable using conventional terrestrial based imaging approaches. This is done by post processing the measured irradiance pattern (shadow) cast onto the Earth as the RSO occults a star. The research presented here focuses on shadow imaging of geosynchronous (GEO) satellites with near stationary orbits approximately 36,000 km from the Earth. Shadows pertaining to a set of diverse observing scenarios are simulated and used as inputs to a Fresnel based phase retrieval algorithm. Spatial resolution limits are evaluated and correlated to signal to noise (SNR) metrics. Resolvable feature sizes of less than 1 m are shown to be readily achievable using foreseeable observing scenarios. Initial output from a shadow prediction tool indicates that there are, on average, over 1000 shadows on the Earth on any given time from a single GEO satellite for stars brighter than mv=10. Shadow ground track uncertainties are correlated to stellar astrometric errors. Global and localized shadow track maps are presented demonstrating a high feasibility for future shadow collections.

  17. Shadow based building extraction from single satellite image

    NASA Astrophysics Data System (ADS)

    Singh, Gurshamnjot; Jouppi, Mark; Zhang, Zhuoran; Zakhor, Avideh

    2015-03-01

    Automatic building extraction in satellite imagery is an important problem. Existing approaches typically involve stereo processing two or more satellite views of the same region. In this paper, we use shadow analysis coupled with line segment detection and texture segmentation to construct rectangular building approximations from a single satellite image. In addition, we extract building heights to construct a rectilinear height profile for a single region. We characterize the performance of the system in rural and urban regions of Jordan, Philippines, and Australia and demonstrate a detection rate of 76.2 - 86.1% and a false alarm rate of 26.5 - 40.1%.

  18. 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.

  19. 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.

  20. Defect detection in partially completed SAW and TIG welds using online radioscopy and image processing

    NASA Astrophysics Data System (ADS)

    Bonser, Gary R.; Lawson, Shaun W.

    1998-03-01

    An application of machine vision applied to the analysis of radioscopic images of incomplete weld geometries is described. The rationale of the work is to identify weld defects as soon as they are produced, thereby reducing the costs of any subsequent repairs. Existing methods of weld and defect identification are compared, leading to the development of filtering and 'window' based variance operator for segmentation of suspect defect areas inside the weld region is described. The software and radioscopic imaging system have been benchmarked through a series of demonstration trials on both 80 mm thick carbon steel submerged arc welded testpieces, and 25mm thick carbon steel tungsten inert gas welded testpieces. The range of intentionally implanted defects, from root cracks to lack of side wall fusion, were detected with an overall accuracy of 87 percent, and classified in terms of defect size, shape, and position within the weld region.

  1. Shadow bands recorded at February 26 eclipse

    NASA Astrophysics Data System (ADS)

    Strach, E. H.

    1998-06-01

    Shadow bands are a curious phenomenon occurring a few minutes before and after a total eclipse of the Sun. They have been seen at many eclipses in the past to a varying intensity but they are notoriously difficult to photograph. These ripples of light and dark bands move very fast and attempts have been made to capture them on cine or video. Shadow bands were captured on video at the eclipse of 1998 February 26.

  2. In the shadow of death.

    PubMed

    Meissner, W W

    1995-08-01

    Death dogged Vincent's footsteps throughout his life, and formed a core component of his unconscious fantasy system. It cast a lugubrious shadow over all of his undertakings--he found little joy and less love in life. It found its way onto his canvases, both directly--the grinning death's head--and indirectly. It found expression in his portrayals of sowers and reapers, in his representations of trees--especially the highly symbolic treatments of cypresses--in the menacing crows hovering over storm-darkened fields of wheat, and finally in the images of Christ, suffering and dead, held in the embrace of a loving and grieving mother. If death was a bottomless pit that haunted him with its terrors, it was also a siren song that drew him ever closer to his destiny, ever closer to the edge of the pit. The power of that attraction lies in his identification with the dead Vincent whose place he had taken and whose name he bore. It was through that identification, and through the passageway of suffering and death that he would surcease in the arms of a loving and accepting mother whose warm embrace he had sought throughout his odyssey, but in vain. It was to be gained only in and through death. It was only through death that he would find rest from his pain and would gain the heavenly reward of his suffering in eternal love and bliss.

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

    DOE PAGES

    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

  4. 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.

  5. 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.

  6. Immobilization of ruthenium phthalocyanine on silica-coated multi-wall partially oriented carbon nanotubes: Electrochemical detection of fenitrothion pesticide

    SciTech Connect

    Canevari, Thiago C.; Prado, Thiago M.; Cincotto, Fernando H.; Machado, Sergio A.S.

    2016-04-15

    Highlights: • Hybrid material, SiO{sub 2}/MWCNTs containing ruthenium phthalocyanine (RuPc) synthesized in situ. • Silica containing multi-walled carbon nanotube partially oriented. • Determination of pesticide fenitrothion in orange juice. - Abstract: This paper reports on the determination of the pesticide fenitrothion using a glassy carbon electrode modified with silica-coated, multi-walled, partially oriented carbon nanotubes, SiO{sub 2}/MWCNTs, containing ruthenium phthalocyanine (RuPc) synthesized in situ. The hybrid SiO{sub 2}/MWCNTs/RuPc material was characterized by UV–vis absorption spectroscopy, X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM), high-resolution transmission electron microscopy (HR-TEM) and differential pulse voltammetry. The modified electrode showed well-defined peaks in the presence of fenitrothion in acetate buffer, pH 4.5, with a sensitivity of 0.0822 μA μM{sup −1} mm{sup −2} and a detection limit of 0.45 ppm. Notably, the modified SiO{sub 2}/MWCNTs/RuPc electrodes with did not suffer from significant influences in the presence of other organophosphorus pesticides during the determination of the fenitrothion pesticide. Moreover, this modified electrode showed excellent performance in the determination of fenitrothion in orange juice.

  7. Detection, localization and quantitation of partial obstruction of common bile duct (CBD) by scintigraphy: Correlation with cholangiogram

    SciTech Connect

    Krishnamurthy, G.T.; Lieberman, D.; Brar, H.

    1984-01-01

    Recent literature in medical journals does not show any major role for scintigraphy in the evaluation of jaundice. A project was undertaken to test critically the role for scintigraphy in the detection, localization and quantification of partial obstruction of CBD using Tc-99m-IDA and the results are correlated with cholangiogram. After 4 to 5 hours of fast, each of 12 patients with documented CBD obstruction was given 3 to 8 mCi of Tc-99m-IDA and serial hepatobiliary images at 2 minute intervals were taken for 90 minutes using gamma camera and the data were collected on computer for quantitation. At 70 minutes 10 ng/kg of CCK-8 was infused over a 3 minute period (n=8). Liver excretion half time, GB ejection fraction (EF) and ejection rate (ER) were obtained. The results were compared with established values in normal subjects. The location of CBD obstruction was made from analogue images. Partial CBD obstruction was characterized in all but one by prolonged liver excretion half time, reduced GB EF and ER (less than 3.5%/min) and intrahepatic bile pooling with excellent CHD and CBD delineation proximal to obstruction thus aiding in the exact anatomic location which correlated well with cholangiogram. The degree of obstruction (ER) correlated well with dilitation of CBD on cholangiogram. These preliminary results show a promise for scintigraphy in the evaluation of CBD obstruction and offer a great potential for non-invasive quantitation of the degree of CBD obstruction.

  8. Detection and partial purification of a potent mitogenic factor for human thyroid follicular cells.

    PubMed

    Bond, J A; Graham, G J; Freshney, M; Dawson, T; Sawhney, N; Williams, E D; Wynford-Thomas, D

    1992-03-01

    Normal adult human thyroid follicular cells have an extremely limited proliferative capacity in vitro. No previously studied mitogen, including thyrotropin (TSH) or epidermal growth factor (EGF), has in our hands resulted in a significant improvement over the 3-4% nuclear [3H]thymidine pulse-labelling index (LI) obtainable with 10% fetal calf serum. Here we report the detection in the conditioned medium from a sub-clone of NIH3T3 fibroblasts of a mitogenic activity capable of increasing this response up to 10-fold, to an LI of over 20%, together with an even greater relative stimulation of mitotic activity. Preliminary characterisation has excluded EGF and TGF alpha, and demonstrated that the activity is bound reversibly by heparin-Sepharose, thus pointing to a member of the heparin-binding fibroblast- or hepatocyte-growth factor families. This material should have wide practical application in facilitating primary culture of follicular cells, and may reveal new mechanisms of stromal-epithelial interaction regulating normal and neoplastic thyroid growth in vivo.

  9. 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.

  10. 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.

  11. 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.

  12. Observation of the cosmic ray moon shadowing effect with the ARGO-YBJ experiment

    NASA Astrophysics Data System (ADS)

    Bartoli, B.; Bernardini, P.; Bi, X. J.; Bleve, C.; Bolognino, I.; Branchini, P.; Budano, A.; Calabrese Melcarne, A. K.; Camarri, P.; Cao, Z.; Cardarelli, R.; Catalanotti, S.; Cattaneo, C.; Celio, P.; Chen, S. Z.; Chen, T. L.; Chen, Y.; Creti, P.; Cui, S. W.; Dai, B. Z.; D'Alí Staiti, G.; Danzengluobu; Dattoli, M.; de Mitri, I.; D'Ettorre Piazzoli, B.; di Girolamo, T.; Ding, X. H.; di Sciascio, G.; Feng, C. F.; Feng, Zhaoyang; Feng, Zhenyong; Galeazzi, F.; Giroletti, E.; Gou, Q. B.; Guo, Y. Q.; He, H. H.; Hu, Haibing; Hu, Hongbo; Huang, Q.; Iacovacci, M.; Iuppa, R.; James, I.; Jia, H. Y.; Labaciren; Li, H. J.; Li, J. Y.; Li, X. X.; Liguori, G.; Liu, C.; Liu, C. Q.; Liu, J.; Liu, M. Y.; Lu, H.; Ma, X. H.; Mancarella, G.; Mari, S. M.; Marsella, G.; Martello, D.; Mastroianni, S.; Montini, P.; Ning, C. C.; Pagliaro, A.; Panareo, M.; Panico, B.; Perrone, L.; Pistilli, P.; Qu, X. B.; Rossi, E.; Ruggieri, F.; Salvini, P.; Santonico, R.; Shen, P. R.; Sheng, X. D.; Shi, F.; Stanescu, C.; Surdo, A.; Tan, Y. H.; Vallania, P.; Vernetto, S.; Vigorito, C.; Wang, B.; Wang, H.; Wu, C. Y.; Wu, H. R.; Xu, B.; Xue, L.; Yan, Y. X.; Yang, Q. Y.; Yang, X. C.; Yao, Z. G.; Yuan, A. F.; Zha, M.; Zhang, H. M.; Zhang, Jilong; Zhang, Jianli; Zhang, L.; Zhang, P.; Zhang, X. Y.; Zhang, Y.; Zhaxiciren; Zhaxisangzhu; Zhou, X. X.; Zhu, F. R.; Zhu, Q. Q.; Zizzi, G.

    2011-07-01

    Cosmic rays are hampered by the Moon and a deficit in its direction is expected (the so-called Moon shadow). The Moon shadow is an important tool to determine the performance of an air shower array. Indeed, the westward displacement of the shadow center, due to the bending effect of the geomagnetic field on the propagation of cosmic rays, allows the setting of the absolute rigidity scale of the primary particles inducing the showers recorded by the detector. In addition, the shape of the shadow permits to determine the detector point spread function, while the position of the deficit at high energies allows the evaluation of its absolute pointing accuracy. In this paper we present the observation of the cosmic ray Moon shadowing effect carried out by the ARGO-YBJ experiment in the multi-TeV energy region with high statistical significance (55 standard deviations). By means of an accurate Monte Carlo simulation of the cosmic rays propagation in the Earth-Moon system, we have studied separately the effect of the geomagnetic field and of the detector point spread function on the observed shadow. The angular resolution as a function of the particle multiplicity and the pointing accuracy have been obtained. The primary energy of detected showers has been estimated by measuring the westward displacement as a function of the particle multiplicity, thus calibrating the relation between shower size and cosmic ray energy. The stability of the detector on a monthly basis has been checked by monitoring the position and the deficit of the Moon shadow. Finally, we have studied with high statistical accuracy the shadowing effect in the day/”night” time looking for possible effect induced by the solar wind.

  13. Detection of melamine adulteration in milk by near-infrared spectroscopy and one-class partial least squares

    NASA Astrophysics Data System (ADS)

    Chen, Hui; Tan, Chao; Lin, Zan; Wu, Tong

    2017-02-01

    Melamine is a noxious nitrogen-rich substance and has been illegally adulterated in milk to boost the protein content. The present work investigated the feasibility of using near-infrared (NIR) spectrum and one-class partial least squares (OCPLS) for detecting the adulteration of melamine. A total of 102 liquor milks were prepared for experiment. A special variable importance (VI) index was defined to select 40 most significant variables. Thirty-two pure milk samples constitute the training set for constructing a one-class model and the other samples were used for the test set. The results showed that on the independent test set, it can achieve an acceptable performance, i.e., the total accuracy of 89%, the sensitivity of 90%, and the specificity of 88%. It seems that the combination of NIR spectroscopy and OCPLS classifier can serve as a potential tool for rapid and on-site screening melamine in milk samples.

  14. 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

  15. 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

  16. Optical Detection of Early Damage in Retinal Ganglion Cells in a Mouse Model of Partial Optic Nerve Crush Injury

    PubMed Central

    Yi, Ji; Puyang, Zhen; Feng, Liang; Duan, Lian; Liang, Peiji; Backman, Vadim; Liu, Xiaorong; Zhang, Hao F.

    2016-01-01

    Purpose Elastic light backscattering spectroscopy (ELBS) has exquisite sensitivity to the ultrastructural properties of tissue and thus has been applied to detect various diseases associated with ultrastructural alterations in their early stages. This study aims to test whether ELBS can detect early damage in retinal ganglion cells (RGCs). Methods We used a mouse model of partial optic nerve crush (pONC) to induce rapid RGC death. We confirmed RGC loss by axon counting and characterized the changes in retinal morphology by optical coherence tomography (OCT) and in retinal function by full-field electroretinogram (ERG), respectively. To quantify the ultrastructural properties, elastic backscattering spectroscopic analysis was implemented in the wavelength-dependent images recorded by reflectance confocal microscopy. Results At 3 days post-pONC injury, no significant change was found in the thickness of the RGC layer or in the mean amplitude of the oscillatory potentials measured by OCT and ERG, respectively; however, we did observe a significantly decreased number of axons compared with the controls. At 3 days post-pONC, we used ELBS to calculate the ultrastructural marker (D), the shape factor quantifying the shape of the local mass density correlation functions. It was significantly reduced in the crushed eyes compared with the controls, indicating the ultrastructural fragmentation in the crushed eyes. Conclusions Elastic light backscattering spectroscopy detected ultrastructural neuronal damage in RGCs following the pONC injury when OCT and ERG tests appeared normal. Our study suggests a potential clinical method for detecting early neuronal damage prior to anatomical alterations in the nerve fiber and ganglion cell layers. PMID:27784071

  17. 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,…

  18. 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…

  19. Job Shadow Guide for Staff [and] Job Shadow Guide for Students. Connections: Linking Work and Learning.

    ERIC Educational Resources Information Center

    Jobs for the Future, Boston, MA.

    "Job shadows" offer young people a chance to investigate the world of work by spending time with adults in the community and experiencing the culture of the workplace. A job shadow gives a student a meaningful introduction to the world of work and provides a context for understanding the connection between school and careers. This guidebook was…

  20. Comparison between blinded and partially blinded detection of gastric cancer with multidetector CT using surgery and endoscopic submucosal dissection as reference standards.

    PubMed

    Kim, H J; Lee, D H; Ko, Y T

    2010-08-01

    The aim of this study is to compare blinded with partially blinded detection of gastric cancer with multidetector (MD) CT by using surgery and endoscopic submucosal dissection (ESD) as reference standards. 44 patients with gastric cancer underwent MDCT with air as an oral contrast agent. Surgery was performed on 37 patients, ESD on six and surgery after ESD on one. To provide comparison cases of blinded evaluation, 38 MDCT examinations were added for cases where no focal gastric lesion was seen on endoscopy. Two radiologists, blinded to the presence, number and location of the tumours, evaluated axial and axial plus multiplanar reformation (MPR) images of 82 MDCT examinations with or without gastric cancer. For partially blinded evaluation, the same radiologists, blinded to the location and number of tumours, evaluated axial and axial plus MPR images of 44 MDCT examinations of gastric cancer. Differences in assessment were resolved by consensus. 45 gastric cancers were found in surgical and ESD specimens. Detection rates of gastric cancer from axial and axial plus MPR images during blinded evaluation and from axial and axial plus MPR images during partially blinded evaluation were 62% (28/45), 64% (29/45), 64% (29/45) and 71% (32/45), respectively. There was no statistical significance for the comparison between blinded and partially blinded detection rates of gastric cancer. The detection rate of gastric cancer with MDCT during blinded evaluation showed no specific difference compared with the detection rate of gastric cancer with MDCT during partially blinded evaluation.

  1. 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.

  2. A Novel High-Performance Beam-Supported Membrane Structure with Enhanced Design Flexibility for Partial Discharge Detection

    PubMed Central

    Fu, Chenzhao; Si, Wenrong; Li, Haoyong; Li, Delin; Yuan, Peng; Yu, Yiting

    2017-01-01

    A novel beam-supported membrane (BSM) structure for the fiber optic extrinsic Fabry-Perot interferometer (EFPI) sensors showing an enhanced performance and an improved resistance to the temperature change was proposed for detecting partial discharges (PDs). The fundamental frequency, sensitivity, linear range, and flatness of the BSM structure were investigated by employing the finite element simulations. Compared with the intact membrane (IM) structure commonly used by EFPI sensors, BSM structure provides extra geometrical parameters to define the fundamental frequency when the diameter of the whole membrane and its thickness is determined, resulting in an enhanced design flexibility of the sensor structure. According to the simulation results, it is noted that BSM structure not only shows a much higher sensitivity (increased by almost four times for some cases), and a wider working range of fundamental frequency to choose, but also an improved linear range, making the system development much easier. In addition, BSM structure presents a better flatness than its IM counterpart, providing an increased signal-to-noise ratio (SNR). A further improvement of performance is thought to be possible with a step-forward structural optimization. The BSM structure shows a great potential to design the EFPI sensors, as well as others for detecting the acoustic signals. PMID:28294962

  3. Electrochemiluminescence detection of NADH and ethanol based on partial sulfonation of sol-gel network with gold nanoparticles.

    PubMed

    Deng, Liu; Zhang, Lihua; Shang, Li; Guo, Shaojun; Wen, Dan; Wang, Fuan; Dong, Shaojun

    2009-03-15

    We developed a stable, sensitive electrochemiluminescence (ECL) biosensor based on the synthesis of a new sol-gel material with the ion-exchange capacity sol-gel to coimmobilize the Ru(bpy)(3)(2+) and enzyme. The partial sulfonated (3-mercaptopropyl)-trimethoxysilane sol-gel (PSSG) film acted as both an ion exchanger for the immobilization of Ru(bpy)(3)(2+) and a matrix to immobilize gold nanoparticles (AuNPs). The AuNPs/PSSG/Ru(bpy)(3)(2+) film modified electrode allowed sensitive the ECL detection of NADH as low as 1 nM. Such an ability of AuNPs/PSSG/Ru(bpy)(3)(2+) film to promote the electron transfer between Ru(bpy)(3)(2+) and the electrode suggested a new, promising biocompatible platform for the development of dehydrogenase-based ECL biosensors. With alcohol dehydrogenase (ADH) as a model, we then constructed an ethanol biosensor, which had a linear range of 5 microM to 5.2 mM with a detection limit of 12nM.

  4. 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).

  5. Quantification of particle sizes with metal replication under standard freeze-etching conditions: a gold ball standard for calibrating shadow widths was used to measure freeze-etched globular proteins.

    PubMed

    Ruben, G C

    1995-11-01

    The real size of platinum-carbon (Pt-C) replicated particles is not directly equivalent to either its metal-coated diameter or its shadow width. This paper describes two indirect methods, shadow widths and coated particle diameters, for determining a particle's actual size beneath a Pt-C replication film. Both produce equivalent measurements using the same standardized conditions: 2.3 nm Pt-C films deposited at a 45 degree angle on an approximately -100 degrees C surface in a 10(-6) torr vacuum. For the first method, gold balls nucleated in a partial pressure of helium and deposited on flat indirect carbon films (root mean square roughness of 0.8 nm) on 400 mesh grids were used as test particles for calibrating shadow widths as a function of particle size. The gold ball test specimens were replicated, and a distribution of Pt-C shadow widths orthogonal to the Pt-C deposition direction was measured and averaged for gold balls 1.5 +/- 0.25 nm, 2.0 +/- 0.25 nm, etc. The diameter of each gold ball was measured within the Pt-C film along with its shadow width because the Pt-C did not obscure or adhere well to the gold. The shadow width distributions for each gold size do not differ significantly from log normal. Two proteins, the lactose repressor and the mitochondrial ATPase, F1, were also used as replication test objects. Negative staining of both proteins was conducted to measure their average diameters. In the second method, a distribution of Pt-C-coated lac repressor diameters perpendicular to the shadow direction was measured. The Pt-C film thickness measured on the quartz crystal monitor was subtracted from the average metal-coated protein diameter to obtain the lac repressor's diameter. The Pt-C-coated particle diameter distributions also did not differ significantly from log normal. While doing this work it was discovered that outgassing the Pt-C electron gun greatly affected Pt-C film granularity: 19 sec produced a high contrast, granular Pt-C film, whereas

  6. Low Frequency Shadowing of the Parkes Superb Survey

    NASA Astrophysics Data System (ADS)

    Bhat, N. D. R.; Kaplan, D. L.; Williams, A.; Wayth, R.

    2017-01-01

    The field of Fast Radio Bursts (FRBs) is rapidly gaining momentum. Since their discovery in the Parkes high time resolution survey (Thornton et al. 2013), the number of reported FRB detections has more than tripled, and measurements have been made of their scattering, scintillation, polarisation and Faraday rotation properties, all of which helped to establish their astrophysical nature. Obser- vational evidence continues to mount in support of their extragalactic origin, and the world-wide competitive race is ramping up as a suite of new and existing instruments are gearing up to find them in large numbers. The SUPERB survey at Parkes has been conceived to realise the important goal of understanding the origin and progenitors of FRBs. An integral part of this survey is co-ordinated multi-wavelength follow-ups and shadowing. Our MWA-based shadowing efforts last year resulted in the first simultaneous multi-frequency observation of an FRB (albeit a non-detection at the MWA), and hence the first broadband limit on the spectral index, as reported in our Nature publication (Keane at al. 2016). After an year-long hiatus the SUPERB survey is scheduled to resume in December 2016. We propose to resume our MWA-based efforts by undertaking effective low-frequency shadowing that is uniquely possible with the MWA. Simultaneous detection of even a single a self-same FRB would bring in a huge science payoff and will yield the first unambiguous constraints on the spectral and scattering properties of FRBs, besides the prospects of sub-arc minute localisation that will be possible with the long baseline array of Phase 2 MWA. We propose to make use of unallocated blocks of time within the schedule, available outside the approved programs and the planned commissioning activities relating to Phase 2. This proposal will thus make excellent use of idle time for an exciting and very important science goal in the nascent field of FRB science.

  7. Shadows alter facial expressions of Noh masks.

    PubMed

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

    2013-01-01

    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. 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. 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.

  8. 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.

  9. Partially Reduced Graphene Oxide Modified Tetrahedral Amorphous Carbon Thin-Film Electrodes as a Platform for Nanomolar Detection of Dopamine

    DOE PAGES

    Wester, Niklas; Sainio, Sami; Palomäki, Tommi; ...

    2017-03-16

    Here, we present for the first time tetrahedral amorphous carbon (ta-C)—a partially reduced graphene oxide (PRGO) hybrid electrode nanomaterial platform for electrochemical sensing of dopamine (DA). Graphene oxide was synthesized with the modified Hummer’s method. Before modification of ta-C by drop casting, partial reduction of the GO was carried out to improve electrochemical properties and adhesion to the ta-C thin film. A facile nitric acid treatment that slightly reoxidized the surface and modified the surface chemistry was subsequently performed to further improve the electrochemical properties of the electrodes. The largest relative increase was seen in carboxyl groups. The HNO3 treatmentmore » increased the sensitivity toward DA and AA and resulted in a cathodic shift in the oxidation of AA. The fabricated hybrid electrodes were characterized with scanning electron microscopy (SEM), Raman spectroscopy, Fourier transform infrared spectroscopy (FT-IR), X-ray photoelectron spectroscopy (XPS), X-ray absorption spectroscopy (XAS), and electrochemical impedance spectroscopy (EIS). Moreover, compared to the plain ta-C electrode the hybrid electrode was shown to exhibit superior sensitivity and selectivity toward DA in the presence of ascorbic acid (AA), enabling simultaneous sensing of AA and DA close to the physiological concentrations by cyclic voltammetry (CV) and by differential pulse voltammetry (DPV). Two linear ranges of 0–1 μM and 1–100 μM and a detection limit (S/N = 3.3) of 2.6 nM for DA were determined by means of cyclic voltammetry. Thus, the current work provides a fully CMOS-compatible carbon based hybrid nanomaterial that shows potential for in vivo measurements of DA.« less

  10. Exploitation of target shadows in synthetic aperture radar imagery for automatic target recognition

    NASA Astrophysics Data System (ADS)

    Saghri, John A.; DeKelaita, Andrew

    2006-08-01

    The utility of target shadows for automatic target recognition (ATR) in synthetic aperture radar (SAR) imagery is investigated. Although target shadow, when available, is not a powerful target discriminating feature, it can effectively increase the overall accuracy of the target classification when it is combined with other target discriminating features such as peaks, edges, and corners. A second and more important utility of target shadow is that it can be used to identify the target pose. Identification of the target pose before the recognition process reduces the number of reference images used for comparison/matching, i.e., the training sets, by at least fifty percent. Since implementation and the computation complexity of the pose detection algorithm is relatively simple, the proposed two-step process, i.e., pose detection followed matching, considerably reduces the complexity of the overall ATR system.

  11. 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.

  12. Interference effect of body shadow in action control.

    PubMed

    Badets, Arnaud; Toussaint, Lucette; Blandin, Yannick; Bidet-Ildei, Christel

    2013-01-01

    Observing actions performed by other persons can subsequently influence our own motor behaviours. However, it is unknown whether the shadows cast by such actions can also have an impact on the observers' actions. Here we show that the mere observation of a cast shadow can influence imitative behaviours. Specifically, participants were shown a hand picture and its associated cast shadow in a neutral position. In a 'compatible trial' the hand and the shadow that followed were turned in the same open or closed direction, whereas in an 'incompatible trial' the hand and the shadow were turned in different directions. We contrasted two experimental conditions: (i) 'hand-shadow' in which participants observed a hand and its cast shadow (the hand covered the shadow); (ii) 'hand-hand' in which participants observed a hand and another black hand (the shadow covered the hand). The participants' task was to imitate (ie by closing or opening their own hands) the hand or the cast shadow of an action. For both conditions results revealed interference (ie longer response latencies) for incompatible trials. This suggests for the first time that the mere observation of a cast shadow of a hand can influence imitative behaviours. However, time courses of the response latencies revealed that imitative effect in the hand-shadow condition was different than the imitative effect in the hand-hand condition. Therefore, we suggest considering the cast shadow of an action as an important feature during motor control for humans.

  13. 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.

  14. Cloud shadow effects on remote sensing

    NASA Technical Reports Server (NTRS)

    Pearce, W. A.

    1985-01-01

    On relatively clear days, the shadow cast by an isolated, optically dense cloud produces an effect which is similar in extent and magnitude to the adjacency effects associated with high-contrast ground albedo boundaries. A Monte Carlo radiative transfer model has been used to examine the intensity and its components, comparing the cloud shadow case with that for a Lambertian albedo boundary. Although the behavior of the total intensity is nearly the same for both cases, the behaviors of the intensity components differ significantly.

  15. A Novel Sensor-Independent Partially-Supervised Approach to Targeted Change Detection: Application to Simulated Sentinel-2 Data

    NASA Astrophysics Data System (ADS)

    Fernandez-Prieto, D.; Marconcini, M.

    2010-12-01

    In several real-world applications (e.g., forestry, agriculture), the objective of change detection is actually limited to one (or few) specific "targeted" land-cover transition(s) affecting a certain area in a given time period. In such cases, ground-truth information is generally available for the only land-cover classes of interest at the two dates, which limits (or hinders) the possibility of successfully employing standard supervised approaches. Moreover, even unsupervised change-detection methods cannot be effectively used, as they allow identifying all the areas experiencing any type of change, but not discriminating where specific land-cover transitions of interest occur. In this paper, we present a novel technique capable of addressing this challenging issue (formulated in terms of a compound decision problem) by exploiting the only ground truth available for the targeted land-cover classes at the two dates. In particular, the proposed method relies on a partially-supervised approach and jointly exploits the Expectation- Maximization (EM) algorithm and an iterative labelling strategy based on Markov random fields (MRF) accounting for spatial and temporal correlation between the two images. Moreover, it also allows handling images acquired by different sensors at the two investigated times. Extensive experimental trials have been carried out with simulated Sentinel-2 Multi-Spectral Instrument (MSI) data derived over Barrax (Castilla-La Mancha, Spain) from airborne images (available from the SPARC 2003 and SPARC 2004 ESA campaigns). Performances were also compared to those obtained by using Landsat-5 Thematic Mapper (TM) data available from the same dates. Final results confirmed the effectiveness and reliability of the proposed technique, as well as the improved discrimination capabilities offered by Sentinel-2 MSI with respect to Landsat-5 TM.

  16. 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.

  17. Detection and follow-up, after partial liver resection, of the urinary paracetamol metabolites by proton NMR spectroscopy.

    PubMed

    Galinski, Michel; Racine, Stephane-Xavier; Bossard, Anne-Elisabeth; Fleyfel, Maher; Hamza, Lilia; Bouchemal, Nadia; Adnet, Frédéric; Le Moyec, Laurence

    2014-01-01

    Combination drug therapy is often used to achieve optimal analgesia in surgery. Paracetamol can be used as one component of an analgesic regime following hepatic resection. This study was designed to investigate paracetamol and its metabolites by proton NMR spectroscopy in patient urine and to assess whether N-acetyl-p-benzoquinone imine (NAPQI, a hepatotoxic metabolite) formation is increased after liver resection. We studied the excretion of acetaminophen and its metabolites by 5 patients who were operated on for partial liver resection by proton NMR spectroscopy. As an intravenous infusion 1 g of paracetamol was given over 15 min every 6 h during 48 h. The first injection was given in the operating theatre after liver resection was completed. Urine samples were collected before injection (T1) and 24 and 48 h after the first injection (T2 and T3); the samples were frozen and kept at -20°C up to the analysis by NMR spectroscopy. Metabolites of the paracetamol were detected for all patients. Among the discerned metabolites, 4 were identified as metabolites of paracetamol: paracetamol glucuronide, paracetamol sulfate, N-acetyl-L-cysteinyl paracetamol (metabolite of NAPQI) and paracetamol. Their ratios, respectively, were: 46-82.9, 12.6-30.0, 0.5-5.5 and 1.43-3.54%. This study showed that there was no increase in the formation of toxic metabolite (NAPQI) after treatment with paracetamol in these few cases of liver resections. A larger study is necessary to confirm these results.

  18. A Double-Partial Least-Squares Model for the Detection of Steady-State Visual Evoked Potentials.

    PubMed

    Ge, Sheng; Wang, Ruimin; Leng, Yue; Wang, Haixian; Lin, Pan; Iramina, Keiji

    2017-07-01

    Establishing a high-accuracy and training-free brain-computer interface (BCI) system is essential for improving BCI practicality. In this study, we propose for the first time a training-free double-partial least-squares (D-PLS) model for steady-state visual evoked potential (SSVEP) detection that consists of double-layer PLS, a PLS spatial filter, and a PLS feature extractor. Electroencephalographic data from 11 healthy volunteers under four different visual stimulation frequencies were used to test the proposed method. Compared with commonly used spatial filters, minimum energy combination and average maximum contrast combination, the classification accuracies could be improved 2-10% by our proposed PLS spatial filter. Furthermore, our proposed PLS feature extractor achieved better performance than current feature extraction methods, namely power spectral density analysis, canonical correlation analysis, and the use of the least absolute shrinkage and selection operator. The average classification accuracy for our proposed D-PLS model exceeded [Formula: see text] when the signal time window was longer than 3.5 s and reached as high as [Formula: see text] when the time window was 5 s. Moreover, the D-PLS model can be easily set without training data, so it can be used widely in SSVEP-based BCI systems.

  19. 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.

  20. The estimation of surface solar radiation considering the distortion of the cloud shadow on complex terrain

    NASA Astrophysics Data System (ADS)

    Xin, X.

    2016-12-01

    Clouds and topography are the two most important factors that affect the surface radiation, and cloud shadows are also an important influencing factor to estimate the surface radiation with remote sensing method. Cloud and its shadow under different observation angle and the angle of the sun will lead to 3-D geometry effect. Furthermore, the terrain also has influence on downward solar radiation. At the same time, the cloud shadow distortion under complex terrain also should be taken into consideration in the estimation of radiation. So "coupling" the clouds and the terrain under the certain condition has the vital significance on estimating the surface radiation values. Cloud detection results of high resolution satellite data was used, according to the height of the cloud and satellite observation angle information the position of cloud on the image was corrected to get the true position of the cloud. To more accurately describe the shadow distortion caused by the terrain, a geometrical method was used to calculate the true position of cloud shadows on complex terrain. On the basis of the result after the calculation of shadows, downward surface solar radiation of the corresponding position was calculated based on some parametric methods for clear and cloudy sky respectively. Then, according to the mountain radiative transfer theory, DEM and albedo was employed in the topographic correction model for the downward surface solar radiation (DSSR) calculated above. Finally, we made some comparisons between cloud shadows on smooth surface and complex terrain as well as DSSR without any correction and with correction of terrain effect. The results showed that it is necessary to make these corrections on complex terrain. There were some big difference of the DSSR distribution and values before making correction.

  1. 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.

  2. NASA's Terra Satellite Sees Shadows of Solar Eclipse

    NASA Image and Video Library

    2017-09-28

    During the morning of March 20, 2015, a total solar eclipse was visible from parts of Europe, and a partial solar eclipse from northern Africa and northern Asia. NASA's Terra satellite passed over the Arctic Ocean on March 20 at 10:45 UTC (6:45 a.m. EDT) and captured the eclipse's shadow over the clouds in the Arctic Ocean. Credit: NASA Goddard MODIS Rapid Response Team NASA image use policy. NASA Goddard Space Flight Center enables NASA’s mission through four scientific endeavors: Earth Science, Heliophysics, Solar System Exploration, and Astrophysics. Goddard plays a leading role in NASA’s accomplishments by contributing compelling scientific knowledge to advance the Agency’s mission. Follow us on Twitter Like us on Facebook Find us on Instagram

  3. 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…

  4. Capturing the Motion of an Eclipse Shadow

    NASA Image and Video Library

    2003-12-04

    Within that narrow window during a solar eclipse where one on Earth can watch the Moon shadow obscure more than 90% of the Sun, NASA Terra spacecraft captured these views of the Antarctic surface during the total solar eclipse of November 23, 2003.

  5. 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…

  6. Turkish Shadow Puppets Yesterday and Today

    ERIC Educational Resources Information Center

    Stokrocki, Mary

    2004-01-01

    A shadow puppet is basically a two-dimensional cut-out form with moving parts. When light is projected behind a screen, the puppet appears as a silhouette, or an opaque drawing in profile. A puppet is successful if it seems to take on a life of its own. Although India is the general source of puppetry that spread throughout Europe through gypsy…

  7. 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…

  8. 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…

  9. ELL Shadowing as a Catalyst for Change

    ERIC Educational Resources Information Center

    Soto, Ivannia

    2012-01-01

    What if you could barely understand what your teacher was saying? Imagine working mostly independently and silently, with limited opportunities to interact with others. ELL shadowing helps teachers better understand the classroom experience from an English language learner's point of view. The author describes how to implement this easily…

  10. Choroidal osteoma: acoustic shadowing and reduplication echoes.

    PubMed

    Abramson, D H; Servodidio, C A; Poole, T A; Budinger, K

    1996-12-01

    A 27-year-old woman had a curious choroidal mass of 12 years duration in her right eye. Interesting ultrasonic findings of a choroidal osteoma, including acoustic shadowing and reduplication echoes on A-scan and B-scan are presented. Ophthalmic nurses can assist in performing ophthalmic examinations and in reinforcing regular follow-up examinations for these patients.

  11. Long cloud shadows stretching hundreds of miles

    NASA Image and Video Library

    1996-02-05

    STS072-308-033 (11-20 Jan. 1996) --- The vertical stabilizer of the Space Shuttle Endeavour almost appears to be pointing out the odd phenomenon of sun streaks and shadows on clouds over the southwestern United States. This was one of seventeen still images shown by the crew members for NASA employees and guests following their stay in space aboard the Endeavour.

  12. Plotting the Analemma from Shadow Stick Observations.

    ERIC Educational Resources Information Center

    Glenn, William H.

    1982-01-01

    Secondary students can study time and the motions of the sun by plotting an analemma, a graphic representation of the declination of the sun and the equation of time for every day of the year. They can collect data by measuring a dowel stick's shadow in the noon sun. (KC)

  13. 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…

  14. Image shadow removal using pulse coupled neural network.

    PubMed

    Gu, Xiaodong; Yu, Daoheng; Zhang, Liming

    2005-05-01

    This paper introduces an approach for image shadow removal by using pulse coupled neural network (PCNN), based on the phenomena of synchronous pulse bursts in the animal visual cortexes. Two shadow-removing criteria are proposed. These two criteria decide how to choose the optimal parameter (the linking strength beta). The computer simulation results of shadow removal based on PCNN show that if these two criteria are satisfied, shadows are removed completely and the shadow-removed images are almost as the same as the original nonshadowed images. The shadow removal results are independent of changes of intensities of shadows in some range and variations of the places of shadows. When the first criterion is satisfied, even if the second criterion is not satisfied, as to natural grey images that have abundant grey levels, shadows also can be removed and PCNN shadow-removed images retain the shapes of the objects in original images. These two criteria also can be used for color images by dividing a color image into three channels (R, G, B). For shadows varying drastically, such as the noisy points in images, these two criteria are still right, but difficult to satisfy. Therefore, this approach can efficiently remove shadows that do not include the random noise.

  15. Shadows Cast On The Transition Disk Of Hd 135344B

    NASA Astrophysics Data System (ADS)

    Stolker, Tomas

    2016-07-01

    I will present new VLT/SPHERE polarimetric imaging observations of the transition disk around HD 135344B (SAO 206462) which have revealed multiple shadow features. These shadows are likely cast by a warped inner disk component and possibly an accretion funnel flow from the inner disk onto the star which might explain the variability of one shadow.

  16. Energy shadowing correction of ultrasonic pulse-echo records by digital signal processing

    NASA Technical Reports Server (NTRS)

    Kishonio, D.; Heyman, J. S.

    1985-01-01

    A numerical algorithm is described that enables the correction of energy shadowing during the ultrasonic testing of bulk materials. In the conventional method, an ultrasonic transducer transmits sound waves into a material that is immersed in water so that discontinuities such as defects can be revealed when the waves are reflected and then detected and displayed graphically. Since a defect that lies behind another defect is shadowed in that it receives less energy, the conventional method has a major drawback. The algorithm normalizes the energy of the incoming wave by measuring the energy of the waves reflected off the water/air interface. The algorithm is fast and simple enough to be adopted for real time applications in industry. Images of material defects with the shadowing corrections permit more quantitative interpretation of the material state.

  17. Shadow-driven 4D haptic visualization.

    PubMed

    Zhang, Hui; Hanson, Andrew

    2007-01-01

    Just as we can work with two-dimensional floor plans to communicate 3D architectural design, we can exploit reduced-dimension shadows to manipulate the higher-dimensional objects generating the shadows. In particular, by taking advantage of physically reactive 3D shadow-space controllers, we can transform the task of interacting with 4D objects to a new level of physical reality. We begin with a teaching tool that uses 2D knot diagrams to manipulate the geometry of 3D mathematical knots via their projections; our unique 2D haptic interface allows the user to become familiar with sketching, editing, exploration, and manipulation of 3D knots rendered as projected imageson a 2D shadow space. By combining graphics and collision-sensing haptics, we can enhance the 2D shadow-driven editing protocol to successfully leverage 2D pen-and-paper or blackboard skills. Building on the reduced-dimension 2D editing tool for manipulating 3D shapes, we develop the natural analogy to produce a reduced-dimension 3D tool for manipulating 4D shapes. By physically modeling the correct properties of 4D surfaces, their bending forces, and their collisions in the 3D haptic controller interface, we can support full-featured physical exploration of 4D mathematical objects in a manner that is otherwise far beyond the experience accessible to human beings. As far as we are aware, this paper reports the first interactive system with force-feedback that provides "4D haptic visualization" permitting the user to model and interact with 4D cloth-like objects.

  18. Dense surface reconstruction with shadows in MIS.

    PubMed

    Lin, Bingxiong; Sun, Yu; Qian, Xiaoning

    2013-09-01

    Three-dimensional reconstruction of internal organ surfaces provides useful information for better control and guidance of the operations of surgical tools for minimally invasive surgery (MIS). The current reconstruction techniques using stereo cameras are still challenging due to the difficulties in correspondence matching in MIS, since there is very limited texture but significant specular reflection on organ surfaces. This paper proposes a new approach to overcome the problem by introducing weakly structured light actively casting surgical tool shadows on organ surfaces. The contribution of this paper is twofold: first, we propose a robust approach to extract shadow edges from a sequence of shadowed images; second, we develop a novel field surface interpolation (FSI) approach to obtain an accurate and dense disparity map. Our approach does not rely on texture information and is able to reconstruct accurate 3-D information by exploiting shadows from surgical tools. One advantage is that the point correspondences are directly calculated and no explicit stereo matching is required, which ensures the efficiency of the method. Another advantage is the minimum hardware requirement because only stereo cameras and a separated single-point light source are required. We evaluated the proposed approach using both phantom models and ex vivo images. Based on the experimental results, we achieved the precision of the recovered 3-D surfaces within 0.7 mm for phantom models and 1.2 mm for ex vivo images. The comparison of disparity maps indicates that with the addition of shadows, the proposed method significantly outperforms the state-of-the-art stereo algorithms for MIS.

  19. 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

  20. Connecting the shadows: probing inner disk geometries using shadows in transitional disks

    NASA Astrophysics Data System (ADS)

    Min, M.; Stolker, T.; Dominik, C.; Benisty, M.

    2017-08-01

    Aims: Shadows in transitional disks are generally interpreted as signs of a misaligned inner disk. This disk is usually beyond the reach of current day high contrast imaging facilities. However, the location and morphology of the shadow features allow us to reconstruct the inner disk geometry. Methods: We derive analytic equations of the locations of the shadow features as a function of the orientation of the inner and outer disk and the height of the outer disk wall. In contrast to previous claims in the literature, we show that the position angle of the line connecting the shadows cannot be directly related to the position angle of the inner disk. Results: We show how the analytic framework derived here can be applied to transitional disks with shadow features. We use estimates of the outer disk height to put constraints on the inner disk orientation. In contrast with the results from Long et al. (2017, ApJ, 838, 62), we derive that for the disk surrounding HD 100453 the analytic estimates and interferometric observations result in a consistent picture of the orientation of the inner disk. Conclusions: The elegant consistency in our analytic framework between observation and theory strongly support both the interpretation of the shadow features as coming from a misaligned inner disk as well as the diagnostic value of near infrared interferometry for inner disk geometry.

  1. 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.

  2. 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.

  3. Surface Water-Ice Deposits in the Northern Shadowed Regions of Ceres

    NASA Technical Reports Server (NTRS)

    Platz, T.; Nathues, A.; Schorghofer, N.; Preusker, F.; Mazarico, E.; Schroeder, S. E.; Byrne, S.; Kneissl, T.; Schmedemann, N.; Combe, J.-P.; hide

    2016-01-01

    Ceres, a dwarf planet located in the main asteroid belt, has a low bulk density, and models predict that a substantial amount of water ice is present in its mantle and outer shell. The Herschel telescope and the Dawn spacecraft have observed the release of water vapor from Ceres, and exposed water ice has been detected by Dawn on its surface at mid-latitudes. Water molecules from endogenic and exogenic sources can also be cold-trapped in permanent shadows at high latitudes, as happens on the Moon and Mercury. Here we present the first image-based survey of Ceres's northern permanent shadows and report the discovery of bright deposits in cold traps. We identify a minimum of 634 permanently shadowed craters. Bright deposits are detected on the floors of just 10 of these craters in multiscattered light. We spectroscopically identify one of the bright deposits as water ice. This detection strengthens the evidence that permanently shadowed areas have preserved water ice on airless planetary bodies.

  4. Shadow response in the blind cavefish Astyanax reveals conservation of a functional pineal eye.

    PubMed

    Yoshizawa, Masato; Jeffery, William R

    2008-02-01

    The blind cavefish Astyanax mexicanus undergoes bilateral eye degeneration during embryonic development. Despite the absence of light in the cave environment, cavefish have retained a structurally intact pineal eye. We show here that contrary to visual degeneration in the bilateral eyes, the cavefish pineal eye has conserved the ability to detect light. Larvae of two different Astyanax cavefish populations and the con-specific sighted surface-dwelling form (surface fish) respond similarly to light dimming by shading the pineal eye. As a response to shading, cavefish larvae swim upward vertically. This behavior resembles that of amphibian tadpoles rather than other teleost larvae, which react to shadows by swimming downward. The shadow response is highest at 1.5-days post-fertilization (d.p.f.), gradually diminishes, and is virtually undetectable by 7.5 d.p.f. The shadow response was substantially reduced after surgical removal of the pineal gland from surface fish or cavefish larvae, indicating that it is based on pineal function. In contrast, removal of one or both bilateral eye primordia did not affect the shadow response. Consistent with its light detecting capacity, immunocytochemical studies indicate that surface fish and cavefish pineal eyes express a rhodopsin-like antigen, which is undetectable in the degenerating bilateral eyes of cavefish larvae. We conclude that light detection by the pineal eye has been conserved in cavefish despite a million or more years of evolution in complete darkness.

  5. Surface Water-Ice Deposits in the Northern Shadowed Regions of Ceres

    NASA Technical Reports Server (NTRS)

    Platz, T.; Nathues, A.; Schorghofer, N.; Preusker, F.; Mazarico, E.; Schroeder, S. E.; Byrne, S.; Kneissl, T.; Schmedemann, N.; Combe, J.-P.; Schaefer, M.; Thangjam, G. S.; Hoffmann, M.; Gutierrez-Marques, P.; Landis, M. E.; Dietrich, W.; Ripken, J.; Matz, K. D.; Russell, C. T.

    2016-01-01

    Ceres, a dwarf planet located in the main asteroid belt, has a low bulk density, and models predict that a substantial amount of water ice is present in its mantle and outer shell. The Herschel telescope and the Dawn spacecraft have observed the release of water vapor from Ceres, and exposed water ice has been detected by Dawn on its surface at mid-latitudes. Water molecules from endogenic and exogenic sources can also be cold-trapped in permanent shadows at high latitudes, as happens on the Moon and Mercury. Here we present the first image-based survey of Ceres's northern permanent shadows and report the discovery of bright deposits in cold traps. We identify a minimum of 634 permanently shadowed craters. Bright deposits are detected on the floors of just 10 of these craters in multiscattered light. We spectroscopically identify one of the bright deposits as water ice. This detection strengthens the evidence that permanently shadowed areas have preserved water ice on airless planetary bodies.

  6. Surface water-ice deposits in the northern shadowed regions of Ceres

    NASA Astrophysics Data System (ADS)

    Platz, T.; Nathues, A.; Schorghofer, N.; Preusker, F.; Mazarico, E.; Schröder, S. E.; Byrne, S.; Kneissl, T.; Schmedemann, N.; Combe, J.-P.; Schäfer, M.; Thangjam, G. S.; Hoffmann, M.; Gutierrez-Marques, P.; Landis, M. E.; Dietrich, W.; Ripken, J.; Matz, K.-D.; Russell, C. T.

    2016-12-01

    Ceres, a dwarf planet located in the main asteroid belt, has a low bulk density1, and models predict that a substantial amount of water ice is present in its mantle and outer shell2-4. The Herschel telescope and the Dawn spacecraft5 have observed the release of water vapour from Ceres6,7, and exposed water ice has been detected by Dawn on its surface at mid-latitudes8. Water molecules from endogenic and exogenic sources can also be cold-trapped in permanent shadows at high latitudes9-11, as happens on the Moon12,13 and Mercury14,15. Here we present the first image-based survey of Ceres's northern permanent shadows and report the discovery of bright deposits in cold traps. We identify a minimum of 634 permanently shadowed craters. Bright deposits are detected on the floors of just 10 of these craters in multi-scattered light. We spectroscopically identify one of the bright deposits as water ice. This detection strengthens the evidence that permanently shadowed areas have preserved water ice on airless planetary bodies.

  7. 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.

  8. Directional Bias in the Perception of Cast Shadows

    PubMed Central

    Koizumi, Tomomi; Sunaga, Shoji; Ogawa, Masaki

    2017-01-01

    Previous studies have demonstrated that the perception of shading is based upon assumptions about lighting direction, for example, light from above. However, it is not clear whether these assumptions are used in the perception of cast shadows. Moreover, it is unclear whether a perceptual interaction exists between shading and cast shadows because until now they have been studied separately. In this study, we investigated through three experiments whether the light-from-above (or another direction) assumption is used in interpreting ambiguous cast shadows, and whether shading information influences the interpretation of cast shadows. Our results indicate the existence of the light-from-above assumption in interpreting cast shadows. Consistent shading information enhanced the interpretation, and judgments of lighting direction were also based on both cast shadow and shading information. However, the perceptual determination of shape from shading was relatively independent of the cast shadow interpretation or the lighting direction judgments of the scene. PMID:28210485

  9. 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

  10. 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.

  11. 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.

  12. Shadow shapes around the black hole in the galactic centre

    NASA Astrophysics Data System (ADS)

    Zakharov, A. F.; Nucita, A. A.; De Paolis, F.; Ingrosso, G.

    Recently Holz & Wheeler (2002) considered a very attracting possibility to detect retro-MACHOs, i.e. retro-images of the Sun by a Schwarzschild black hole. In this paper we discuss glories (mirages) formed near rapidly rotating Kerr black hole horizons and propose a procedure to measure masses and rotation parameters analyzing these forms of mirages. In some sense that is a manifestation of gravitational lens effect in the strong gravitational field near black hole horizon and a generalization of the retro-gravitational lens phenomenon. We analyze the case of a Kerr black hole rotating at arbitrary speed for some selected positions of a distant observer with respect to the equatorial plane of a Kerr black hole. We discuss glories (mirages) formed near rapidly rotating Kerr black hole horizons and propose a procedure to measure masses and rotation parameters analyzing these forms of mirages. Some time ago Falcke, Melia & Agol (2000) suggested to search shadows at the Galactic Center. In this paper we present the boundaries for shadows calculated numerically. We also propose to use future radio interferometer RADIOASTRON facilities to measure shapes of mirages (glories) and to evaluate the black hole spin as a function of the position angle of a distant observer.

  13. Shadows (Mirages) Around Black Holes and Retro Gravitational Lensing

    NASA Astrophysics Data System (ADS)

    Zakharov, A. F.; Nucita, A. A.; Depaolis, F.; Ingrosso, G.

    Recently Holz & Wheeler [1] considered a very attracting possibility to detect retro-MACHOs, i.e. retro-images of the Sun by a Schwarzschild black hole. In this paper we discuss glories (mirages) formed near rapidly rotating Kerr black hole horizons and propose a procedure to measure masses and rotation parameters analyzing these forms of mirages (a detailed description of the problem is given in [2]). In some sense that is a manifestation of gravitational lens effect in the strong gravitational field near black hole horizon and a generalization of the retro-gravitational lens phenomenon. We analyze the case of a Kerr black hole rotating at arbitrary speed for some selected positions of a distant observer with respect to the equatorial plane of a Kerr black hole. Some time ago Falcke, Melia & Agol [3] suggested to search shadows at the Galactic Center. In this paper we present the boundaries for shadows calculated numerically. We also propose to use future radio interferometer RADIOASTRON facilities to measure shapes of mirages (glories) and to evaluate the black hole spin as a function of the position angle of a distant observer.

  14. 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.

  15. Nuclear Shadowing at Small Values of X.

    NASA Astrophysics Data System (ADS)

    Qiu, Jian-Wei

    The nuclear parton distributions are given in a model where the nucleus is viewed as a collection of uncorrelated nucleons. Using these distributions, we determine nuclear shadowing at small values of x. We find that the effect of nuclear shadowing goes away very slowly when Q^2 increases. Our results are consistent with the experiment of Goodman et al. Using these distributions, we also determine the A-dependence of hadronic charm productions. Defining total cross sections of hadronic charm production in pA and pp collisions as sigma_{rm pAto c | c} = A^alpha sigma_{rm ppto c| c}, we find that alpha is bigger than 0.96 for all physically existing nuclei at present collider energies.

  16. Shadow-based SAR ATR performance prediction

    NASA Astrophysics Data System (ADS)

    Blacknell, D.

    2009-05-01

    The ability to assess potential automatic target recognition (ATR) performance for a given SAR system, target set and clutter environment is a key requirement for system procurement and mission planning. A cost-effective solution is to develop a theoretical model which can provide ATR performance predictions given a parameterisation of the system, targets and environment. In this paper, a classification scheme based on shadow information is analysed. Consideration of the statistical accuracy of shadow-based features allows ATR performance to be predicted. Quantitative comparisons of predicted performance with results obtained via simulation as well as against real data from the MSTAR data set are presented. It is seen that a reasonable level of agreement is obtained which gives confidence in extending the theoretical concepts to more complex feature-based ATR schemes.

  17. 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.

  18. Artificial Seismic Shadow Zone by Acoustic Metamaterials

    NASA Astrophysics Data System (ADS)

    Kim, Sang-Hoon; Das, Mukunda P.

    2013-08-01

    We developed a new method of earthquake-proof engineering to create an artificial seismic shadow zone using acoustic metamaterials. By designing huge empty boxes with a few side-holes corresponding to the resonance frequencies of seismic waves and burying them around the buildings that we want to protect, the velocity of the seismic wave becomes imaginary. The meta-barrier composed of many meta-boxes attenuates the seismic waves, which reduces the amplitude of the wave exponentially by dissipating the seismic energy. This is a mechanical method of converting the seismic energy into sound and heat. We estimated the sound level generated from a seismic wave. This method of area protection differs from the point protection of conventional seismic design, including the traditional cloaking method. The artificial seismic shadow zone is tested by computer simulation and compared with a normal barrier.

  19. Scaling and shadowing effects in ballistic aggregation

    NASA Astrophysics Data System (ADS)

    Joag, P. S.; Limaye, A. V.; Amritkar, R. E.

    1987-10-01

    We have studied the scaling and shadowing properties of two-dimensional off-lattice ballistic aggregation on a seed. The computer simulations show that the limiting semivertical cone angle is about 15.5°. The density as a function of distance from the seed tends to a constant value showing a basic two-dimensional nature of the aggregates and has a correction with a metadimension of about 0.56. The density as a function of angle near the edges of the cone is found to obey a scaling relation similar to the on-lattice case. The probabilities for the fingers of different lengths which shadow the particle near the edge are determined in the computer experiment and also determined analytically.

  20. Shadow Imaging Efforts at MIT Lincoln Laboratory

    DTIC Science & Technology

    2008-09-01

    the receiver with a spectrometer consisting of a grating and a Geiger - mode avalanche photodiode array. 2. RESOLUTION LIMITS Shadow...A good choice would be photon-counting detectors such as Geiger - mode avalanche photodiodes (APDs) (currently used in our proof-of- concept...170μm-diameter silicon avalanche photodiode (APD) (the Perkin-Elmer SPCM-AQRH-15). The observations will yield a single chord of the diffraction

  1. 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.

  2. Symbolic Substitution Using Shadow-Casting

    NASA Astrophysics Data System (ADS)

    Xue, Wei; Chen, Li-Xue; Li, Chun-Fei; Hu, Qiang-Sheng

    1989-02-01

    A new optical system for symbolic substitution is proposed. The system is composed of the lensless shadow-casting system combined with optical logical array and optical image storage elements. The LED's (light-emitting diode) are used as both a light source and a control element in the operation, so that symbolic substitution is implemented by all-photoelectric manipulation. Experimental principle, procedure and result are given.

  3. 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.

  4. Nebkha flow dynamics and shadow dune formation

    NASA Astrophysics Data System (ADS)

    Hesp, Patrick A.; Smyth, Thomas A. G.

    2017-04-01

    In this study, wind flow is simulated via CFD over five 'nebkha' dune forms that range in shape from a cone, to a hemisphere (approximately) and to a dome in order to examine the structure of the wake zone formed downwind and the effect on the leeward flow separation zone and shadow dune formation. Dune height was fixed at 0.5 m while the nebkha diameter increased in 0.25 m increments from 0.5 m to 1.5 m and aspect ratio (h/D) from 1.0 to 0.3. The mean flow comprises an upwind region of reduced velocity which expands as nebkha width increases, high velocity marginal wings, and paired counter-rotating reversing vortices leeward of the nebkha. The point at which flow separation occurs moves further downwind as the nebkha diameter increases. The core regions of the reversing vortices are situated further downwind behind the smaller nebkha than in the case of the larger nebkha. These factors in combination allow for higher velocity perturbations (TKE) and narrower wake behind the smaller nebkha, and the suppression of downwind wake development in the case of the increasingly larger nebkha. Shadow dune length increases as nebkha width increases for lower incident velocity flow and is barely affected by nebkha width at higher flows. The extent of the leeward separation or wake zone, and hence shadow dune length, more strongly varies as a function of wind velocity.

  5. Perception of shadows in children with autism spectrum disorders.

    PubMed

    Becchio, Cristina; Mari, Morena; Castiello, Umberto

    2010-05-11

    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. 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. 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.

  6. Is a career in medicine the right choice? The impact of a physician shadowing program on undergraduate premedical students.

    PubMed

    Wang, Jennifer Y; Lin, Hillary; Lewis, Patricia Y; Fetterman, David M; Gesundheit, Neil

    2015-05-01

    Undergraduate (i.e., baccalaureate) premedical students have limited exposure to clinical practice before applying to medical school-a shortcoming, given the personal and financial resources required to complete medical training. The Stanford Immersion in Medicine Series (SIMS) is a program that streamlines the completion of regulatory requirements for premedical students and allows them to develop one-on-one mentor-mentee relationships with practicing physicians. The program, offered quarterly since 2007, is an elective available for Stanford University sophomores, juniors, and seniors. Participants apply to the program and, if accepted, receive patient rights and professionalism training. Students shadow the physician they are paired with at least four times and submit a reflective essay about their experience.SIMS program coordinators administered surveys before and after shadowing to assess changes in students' perceptions and understanding of medical careers. The authors observed, in the 61 Stanford premedical students who participated in SIMS between March and June 2010 and completed both pre- and postprogram questionnaires, significant increases in familiarity with physician responsibilities and in understanding physician-patient interactions. The authors detected no significant changes in student commitment to pursuing medicine. Student perceptions of the value of shadowing-high both pre- and post shadowing-did not change. Physician shadowing by premedical baccalaureate students appears to promote an understanding of physician roles and workplace challenges. Future studies should identify the ideal timing, format, and duration of shadowing to optimize the experience and allow students to make informed decisions about whether to pursue a medical career.

  7. 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

  8. Coherent detection of frequency-hopped quadrature modulations in the presence of jamming. II - QPR Class I modulation. [Quadrature Partial Response

    NASA Technical Reports Server (NTRS)

    Simon, M. K.

    1981-01-01

    This paper considers the performance of quadrature partial response (QPR) in the presence of jamming. Although a QPR system employs a single sample detector in its receiver, while quadrature amplitude shift keying (or quadrature phase shift keying) requires a matched-filter type of receiver, it is shown that the coherent detection performances of the two in the presence of the intentional jammer have definite similarities.

  9. Coherent detection of frequency-hopped quadrature modulations in the presence of jamming. II - QPR Class I modulation. [Quadrature Partial Response

    NASA Technical Reports Server (NTRS)

    Simon, M. K.

    1981-01-01

    This paper considers the performance of quadrature partial response (QPR) in the presence of jamming. Although a QPR system employs a single sample detector in its receiver, while quadrature amplitude shift keying (or quadrature phase shift keying) requires a matched-filter type of receiver, it is shown that the coherent detection performances of the two in the presence of the intentional jammer have definite similarities.

  10. Bladder carcinoma with shadow cell differentiation: a case report with immunohistochemical analyses.

    PubMed

    Nakamura, Toshitsugu

    2012-01-01

    A peculiar case of bladder carcinoma showing shadow cell differentiation (SCD) in a 72-year-old man is presented. The tumor histologically revealed high grade urothelial carcinoma (UC) and partially contained squamous component with a transition to shadow cell nests, similar to those seen in cutaneous pilomatricoma (PMX). Immunohistochemically, the modes of cell death in the component of SCD were identical to those in PMX. The present case as well as 10 cases of cutaneous PMX showed nuclear expression of beta-catenin, whereas 10 cases of bladder UC with squamous differentiation revealed membranous localization without nuclear expression. These results suggest that nuclear accumulation of beta-catenin may play an important role for SCD in the present case. SCD in extracutaneous tumor is extremely rare and, in the literature, the present case is the second one as for bladder carcinoma.

  11. Direct 3D printed shadow mask on Silicon

    NASA Astrophysics Data System (ADS)

    Rahiminejad, S.; Köhler, E.; Enoksson, P.

    2016-10-01

    A 3D printed shadow mask method is presented. The 3D printer prints ABS plastic directly on the wafer, thus avoiding gaps between the wafer and the shadow mask, and deformation during the process. The wafer together with the 3D printed shadow mask was sputtered with Ti and Au. The shadow mask was released by immersion in acetone. The sputtered patches through the shadow mask were compared to the opening of the 3D printed shadow mask and the design dimensions. The patterned Au patches were larger than the printed apertures, however they were smaller than the design widths. The mask was printed in 4 min, the cost is less than one euro cent, and the process is a low temperature process suitable for temperature sensitive components.

  12. 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.

  13. 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.

  14. 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

  15. 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.

  16. 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. Copyright © 2014 Elsevier B.V. All rights reserved.

  17. Ultraviolet Shadowing of RNA Can Cause Significant Chemical Damage in Seconds

    PubMed Central

    Kladwang, Wipapat; Hum, Justine; Das, Rhiju

    2012-01-01

    Chemical purity of RNA samples is important for high-precision studies of RNA folding and catalytic behavior, but photodamage accrued during ultraviolet (UV) shadowing steps of sample preparation can reduce this purity. Here, we report the quantitation of UV-induced damage by using reverse transcription and single-nucleotide-resolution capillary electrophoresis. We found photolesions in a dozen natural and artificial RNAs; across multiple sequence contexts, dominantly at but not limited to pyrimidine doublets; and from multiple lamps recommended for UV shadowing. Irradiation time-courses revealed detectable damage within a few seconds of exposure for 254 nm lamps held at a distance of 5 to 10 cm from 0.5-mm thickness gels. Under these conditions, 200-nucleotide RNAs subjected to 20 seconds of UV shadowing incurred damage to 16-27% of molecules; and, due to a ‘skin effect’, the molecule-by-molecule distribution of lesions gave 4-fold higher variance than a Poisson distribution. Thicker gels, longer wavelength lamps, and shorter exposure times reduced but did not eliminate damage. These results suggest that RNA biophysical studies should report precautions taken to avoid artifactual heterogeneity from UV shadowing. PMID:22816040

  18. 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

  19. 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

  20. 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.

  1. [Joseph Rollet & the shadow of Ricord].

    PubMed

    Chevallier, Jacques

    2010-01-01

    There are three distinguished names in French venereology during the first half of XIXth century: Ricord, Bassereau and Rollet. Ricord is above all a colourful practitioner of fashionable circles and he takes care of a lot of VIP: political people, actors, writers ... With his influence he takes strong opinions but in fact he has only linked gonorrhoea with veneral ulcers. Joseph Rollet head surgeon in the Antiquaille hospital of Lyon, continuing the studies of Bassereau, proves many basic points about venereal diseases often opposed to the theories of Ricord. So theses two scientists too discret or provincial will remain in the shadow of Ricord.

  2. aCGH detects partial tetrasomy of 12p in blood from Pallister-Killian syndrome cases without invasive skin biopsy.

    PubMed

    Theisen, Aaron; Rosenfeld, Jill A; Farrell, Sandra A; Harris, Catharine J; Wetzel, Heather H; Torchia, Beth A; Bejjani, Bassem A; Ballif, Blake C; Shaffer, Lisa G

    2009-05-01

    Pallister-Killian syndrome (PKS) is a genetic disorder characterized by mental retardation, seizures, streaks of hypo- or hyperpigmentation and dysmorphic features. PKS is associated with tissue-limited mosaic partial tetrasomy of 12p, usually caused by an isochromosome 12p. The mosaicism is usually detected in cultured skin fibroblasts or amniotic cells and rarely in phytohemagluttinin-stimulated lymphocytes, which suggests stimulation of T-lymphocytes may distort the percentage of abnormal cells. We recently reported on the identification by microarray-based comparative genomic hybridization (aCGH) of a previously unsuspected case of partial tetrasomy of 12p caused by an isochromosome 12p. Here we report on seven additional individuals with partial tetrasomy of 12p characterized by our laboratory. All individuals were referred for mental retardation/developmental delay and/or dysmorphic features. In each case, aCGH using genomic DNA extracted from whole peripheral blood detected copy-number gain for all clones for the short arm of chromosome 12. In all but one case, FISH on metaphases from cultured lymphocytes did not detect the copy-number gain; in the remaining case, metaphase FISH on cultured lymphocytes showed an isochromosome in 10% of cells. However, interphase FISH using probes to 12p on peripheral blood smears showed additional hybridization signals in 18-70% of cells. Microarray and FISH analysis on cultured skin biopsies from four individuals confirmed the presence of an isochromosome 12p. Our results demonstrate the usefulness of aCGH with genomic DNA from whole peripheral blood to detect chromosome abnormalities that are not present in stimulated blood cultures and would otherwise require invasive skin biopsies for identification.

  3. 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.

  4. 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

  5. The shadow price of fossil groundwater

    NASA Astrophysics Data System (ADS)

    Bierkens, M. F.; Reinhard, S.; De Bruijn, J.; Wada, Y.

    2016-12-01

    The expansion of irrigated agriculture into areas with limited precipitation and surface water during the growing season has greatly increased the use of fossil groundwater (Wada et al., 2012). As a result, the depletion rate of fossil groundwater resources has shown an increasing rate during the last decades (Wada et al, 2010; Konikow, 2011; Wada et al., 2012; De Graaf et al. 2015; Ritchy et al., 2015). Although water pricing has been used extensively to stimulate efficient application of water to create maximum value (e.g. Medellín-Azuara et al., 2012; Rinaudo et al., 2012; Dinar et al., 2015), it does not preclude the use of non-renewable water resources. Here, we use a global hydrological model and historical crop production and price data to assess the shadow price of non-renewable or fossil groundwater applied to major crops in countries that use large quantities of fossil groundwater. Our results show that shadow prices for many crops are very low, indicating economically inefficient or even wasteful use of fossil groundwater resources. Using India as an example, we show that small changes in the crop mix could lead to large reductions in fossil groundwater use or alternatively, create additional financial means to invest in water saving technologies. Our study thus provides a hydro-economic basis to further the sustainable use of finite groundwater resources.

  6. Shadowing in low-energy photonuclear reactions

    NASA Astrophysics Data System (ADS)

    Das, Swapan

    2017-09-01

    The photonuclear reaction in the multi-GeV region occurs because of the electromagnetic and hadronic interactions. The latter originates due to the hadronic fluctuation, i.e., vector meson, of the photon. The total cross section of the reaction is shadowed because of the vector meson-nucleus (hadronic) interaction. To estimate it quantitatively, the cross section of the photonuclear reaction was calculated in the low energy region (˜1 -3 GeV) using the simple vector-meson dominance (SVMD) model, i.e., the low-lying vector mesons (ρ0, ω , and ϕ mesons) were considered. The nuclear shadowing is reinvestigated using the generalized vector meson (GVMD) model, where the higher ρ meson effective state (ρ' meson) is taken into account along with the low-lying vector mesons. Using the GVMD model, the total cross section of the photonuclear reaction are calculated in the above mentioned energy region. The calculated results are compared with the measured spectra.

  7. The shadow price of fossil groundwater

    NASA Astrophysics Data System (ADS)

    Bierkens, Marc F. P.; Reinhard, Stijn; de Bruijn, Jens A.; Wada, Yoshihide

    2017-04-01

    The expansion of irrigated agriculture into areas with limited precipitation and surface water during the growing season has greatly increased the use of fossil groundwater (Wada et al., 2012). As a result, the depletion rate of fossil groundwater resources has shown an increasing rate during the last decades (Wada et al, 2010; Konikow, 2011; Wada et al., 2012; De Graaf et al. 2015; Ritchy et al., 2015). Although water pricing has been used extensively to stimulate efficient application of water to create maximum value (e.g. Medellín-Azuara et al., 2012; Rinaudo et al., 2012; Dinar et al., 2015), it does not preclude the use of non-renewable water resources. Here, we use a global hydrological model and historical crop production and price data to assess the shadow price of non-renewable or fossil groundwater applied to major crops in countries that use large quantities of fossil groundwater. Our results show that shadow prices for many crops are very low, indicating economically inefficient or even wasteful use of fossil groundwater resources. Using India as an example, we show that small changes in the crop mix could lead to large reductions in fossil groundwater use or alternatively, create additional financial means to invest in water saving technologies. Our study thus provides a hydro-economic basis to further the sustainable use of finite groundwater resources.

  8. 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…

  9. Shadows of Einstein-dilaton-Gauss-Bonnet black holes

    NASA Astrophysics Data System (ADS)

    Cunha, Pedro V. P.; Herdeiro, Carlos A. R.; Kleihaus, Burkhard; Kunz, Jutta; Radu, Eugen

    2017-05-01

    We study the shadows of the fully non-linear, asymptotically flat Einstein-dilaton-Gauss-Bonnet (EdGB) black holes (BHs), for both static and rotating solutions. We find that, in all cases, these shadows are smaller than for comparable Kerr BHs, i.e. with the same total mass and angular momentum under similar observation conditions. In order to compare both cases we provide quantitative shadow parameters, observing in particular that the differences in the shadows mean radii are never larger than the percent level. Therefore, generically, EdGB BHs cannot be excluded by (near future) shadow observations alone. On the theoretical side, we find no clear signature of some exotic features of EdGB BHs on the corresponding shadows, such as the regions of negative (Komar, say) energy density outside the horizon. We speculate that this is due to the fact that the Komar energy interior to the light rings (or more precisely, the surfaces of constant radial coordinate that intersect the light rings in the equatorial plane) is always smaller than the ADM mass, and consequently the corresponding shadows are smaller than those of comparable Kerr BHs. The analysis herein provides a clear example that it is the light ring impact parameter, rather than its ;size;, that determines a BH shadow.

  10. 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…

  11. 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…

  12. 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.

  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.

  14. Chasing Shadows: Rotation of the Azimuthal Asymmetry in the TW Hya Disk

    NASA Technical Reports Server (NTRS)

    Debes, John H.; Poteet, Charles A.; Jang-Condell, Hannah; Gaspar, Andras; Hines, Dean; Kastner, Joel H.; Pueyo, Laurent; Rapson, Valerie; Roberge, Aki; Schneider, Glenn; hide

    2017-01-01

    We have obtained new images of the protoplanetary disk orbiting TW Hya in visible, total intensity light with the Space Telescope Imaging Spectrograph (STIS) on the Hubble Space Telescope (HST), using the newly commissioned BAR5 occulter. These HSTSTIS observations achieved an inner working angle of approximately 0 "2, or11.7 au, probing the system at angular radii coincident with recent images of the disk obtained by ALMA and in polarized intensity near-infrared light. By comparing our new STIS images to those taken with STIS in 2000 and with NICMOS in 1998, 2004, and 2005, we demonstrate that TW Hyas azimuthal surface brightness asymmetry moves coherently in position angle. Between 50 au and 141 au we measure a constant angular velocity in the azimuthal brightness asymmetry of 22.deg7 yr(exp -1) in a counterclockwise direction, equivalent to a period of 15.9yrassuming circular motion. Both the (short) inferred period and lack of radial dependence of the moving shadow pattern are inconsistent with Keplerian rotation at these disk radii. We hypothesize that the asymmetry arises from the fact that the disk interior to 1 au is inclined and precessing owing to a planetary companion, thus partially shadowing the outer disk. Further monitoring of this and other shadows on protoplanetary disks potentially opens anew avenue for indirectly observing the sites of planet formation.

  15. 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.

  16. 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

  17. 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.

  18. 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.

  19. Synoptic and mesoscale controls on Sierra Nevada rain shadow intensity

    NASA Astrophysics Data System (ADS)

    Hatchett, B.; Kaplan, M.; Rutz, J. J.; Garner, C.

    2016-12-01

    The Sierra Nevada of California casts one of the world's greatest rain shadows with windward-leeside precipitation differences approaching an order of magnitude. Leeside rivers and terminal lakes provide critical water resources for ecosystem services and human consumptive use in this water-limited environment. They also offer important archives of paleohydroclimatic change. Understanding the drivers of rain shadow intensity represents an important step in properly evaluating how leeside hydrology will respond to projected climate change and for interpreting increasingly well spatially distributed paleoproxy evidence of past hydroclimates. Recent theoretical and modeling studies have shown rain shadow intensity to be controlled by multiscalar dynamics during storms such as the vertical structure of mountain waves, the presence of mid-level moisture, and position of the warm sector with respect to the mountain crest. Here, we provide a 35-year station-based climatology of strong and weak rain shadow events for the central Sierra Nevada during extended winter (November-April). Wetter (drier) years in leeside basins are characterized by higher (lower) fractions of lee-crest precipitation suggesting weaker (stronger) rain shadow effects during precipitation events. In general, as contributions of precipitation on the climatological top 5% of wet days increases, rain shadow intensity decreases. This suggests a key role for atmospheric rivers in weakening the rain shadow. A separate population of very dry years is found, regardless of number of dry days, when no precipitation is contributed by the climatological top 5% of wet days. These years show stronger rain shadow effects with few exceptions. Using the North American Regional Reanalysis and both surface and satellite-based remote sensing data in conjunction with the derived rain shadow climatology, we demonstrate the additional importance of atmospheric rivers, offshore and upstream mesoscale convection, and

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

    PubMed Central

    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

  1. 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

    2016-07-26

    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.

  2. Detecting equilibrium cytochrome c folding intermediates by electrospray ionisation mass spectrometry: Two partially folded forms populate the molten-globule state

    PubMed Central

    Grandori, Rita

    2002-01-01

    Nanoelectrospray ionization mass spectrometry (nano-ESI-MS) is applied to the characterization of ferric cytochromec (cytc) conformational states under different solvent conditions. The methanol-induced molten-globule state in the pH range 2.6–3.0 is found to be populated by two distinct, partially folded conformers IA and IB. The more compact intermediate IB resembles that induced by glycerol in acid-unfolded cytc. The less compact one, IA, also can be induced by destabilization of the native structure by trifluoroethanol. IA and IB can be detected, in the absence of additives, around the midpoint of the acid-induced unfolding transition, providing direct evidence for involvement of equilibrium folding intermediates in cytc conformational transitions at low pH. This study shows that mass spectrometry can contribute to the characterization of molten-globule states of proteins by detection of distinct, although poorly populated, conformations involved in a dynamic equilibrium. PMID:11847268

  3. The Shadow Knows: Using Shadows to Investigate the Structure of the Pretransitional Disk of HD 00453

    NASA Astrophysics Data System (ADS)

    Long, Zachary; Fernandes, Rachel B.; Sitko, Michael L.; Grady, Carol A.; Muto, Takayuki; Hashimoto, Jun; Wisniewski, John P.; SEEDS Consortium

    2017-01-01

    With the advent of extreme AO instruments we have begun to obtain more detailed images of circumstellar disks. Recently these images have revealed several disks which contain azimuthally- localized dark features, such as HD 100453, some of which have been interpreted as shadows cast by an inner disk component which is not coplanar with the outer disk. Through careful study of these dark features we are able to probe the structure of the disk and make testable predictions using a 3D Monte Carlo radiative transfer code. Through the use of this code and comparison to recent SPHERE and GPI images we have determined that the shadows seen in the circumstellar disk of HD 100453 are caused by a misinclined inner disk which is at an inclination approximately 45° from coplanarity. In order to cause this misinclination the disk must have undergone a signicant torqueing event such as giant planet-giant planet scattering.

  4. THE EFFECTS OF SELF-SHADOWING BY A PUFFED-UP INNER RIM IN SCATTERED LIGHT IMAGES OF PROTOPLANETARY DISKS

    SciTech Connect

    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. 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.

  6. [Pharmacy and art: Turkish's shadows and colors].

    PubMed

    Nicolas, Michèle

    2002-01-01

    Karagöz is the name of the Turkish shadow theater and in the same time the name of the principal hero: it means "black eye". This burlesque show was performed on great occasions, such as births, circumcisions, weddings, and also during the winter evenings and the month of Ramadan. The size of puppets, in camel hide, is generally 25/35 cm. Sketches are inspired by daily life in big anatolian cities and in Istanbul. In this play, Karagöz is both pharmacist and doctor, a job for which he is not at all qualified. Of course, the farce is embroidered around his extravagant speeches and acts when different people come in the pharmacy. We notice the importance of the French vocabulary.

  7. Multi-probe-based resonance-frequency electrical impedance spectroscopy for detection of suspicious breast lesions: improving performance using partial ROC optimization

    NASA Astrophysics Data System (ADS)

    Lederman, Dror; Zheng, Bin; Wang, Xingwei; Wang, Xiao Hui; Gur, David

    2011-03-01

    We have developed a multi-probe resonance-frequency electrical impedance spectroscope (REIS) system to detect breast abnormalities. Based on assessing asymmetry in REIS signals acquired between left and right breasts, we developed several machine learning classifiers to classify younger women (i.e., under 50YO) into two groups of having high and low risk for developing breast cancer. In this study, we investigated a new method to optimize performance based on the area under a selected partial receiver operating characteristic (ROC) curve when optimizing an artificial neural network (ANN), and tested whether it could improve classification performance. From an ongoing prospective study, we selected a dataset of 174 cases for whom we have both REIS signals and diagnostic status verification. The dataset includes 66 "positive" cases recommended for biopsy due to detection of highly suspicious breast lesions and 108 "negative" cases determined by imaging based examinations. A set of REIS-based feature differences, extracted from the two breasts using a mirror-matched approach, was computed and constituted an initial feature pool. Using a leave-one-case-out cross-validation method, we applied a genetic algorithm (GA) to train the ANN with an optimal subset of features. Two optimization criteria were separately used in GA optimization, namely the area under the entire ROC curve (AUC) and the partial area under the ROC curve, up to a predetermined threshold (i.e., 90% specificity). The results showed that although the ANN optimized using the entire AUC yielded higher overall performance (AUC = 0.83 versus 0.76), the ANN optimized using the partial ROC area criterion achieved substantially higher operational performance (i.e., increasing sensitivity level from 28% to 48% at 95% specificity and/ or from 48% to 58% at 90% specificity).

  8. 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.

  9. Detecting and exploring partially unfolded states of proteins using a sensor with chaperone bound to its surface.

    PubMed

    George, Doaa F; Bilek, Marcela M M; McKenzie, David R

    2008-12-01

    We have developed a sensor concept capable of discriminating environments that induce proteins to enter unfolding intermediate states. Such a sensor detects the presence of environmental stressors such as chemical agents in aqueous media, thermal stress or the presence of ionizing or non-ionizing radiation by monitoring the conformation state of a "sensor protein". In this paper, we demonstrate the concept by using surface plasmon resonance to monitor binding of thermally and chemically stressed sensor proteins to a chaperone, alpha-crystallin, bound to the sensor surface. Citrate synthase and insulin were used as example sensor proteins to detect the presence of thermal stress and chemical stress, respectively. It was shown that alpha-crystallin retained its chaperone action after immobilization on the Biacore sensor chip. The binding of early and late unfolding intermediates of citrate synthase was discriminated using the association and dissociation behaviour of the binding. The sensor is therefore capable of assessing the severity of an environmental stress.

  10. Automatic lumbar vertebrae detection based on feature fusion deep learning for partial occluded C-arm X-ray images.

    PubMed

    Li, Yang; Liang, Wei; Zhang, Yinlong; An, Haibo; Tan, Jindong; Yang Li; Wei Liang; Yinlong Zhang; Haibo An; Jindong Tan; Li, Yang; Liang, Wei; Tan, Jindong; Zhang, Yinlong; An, Haibo

    2016-08-01

    Automatic and accurate lumbar vertebrae detection is an essential step of image-guided minimally invasive spine surgery (IG-MISS). However, traditional methods still require human intervention due to the similarity of vertebrae, abnormal pathological conditions and uncertain imaging angle. In this paper, we present a novel convolutional neural network (CNN) model to automatically detect lumbar vertebrae for C-arm X-ray images. Training data is augmented by DRR and automatic segmentation of ROI is able to reduce the computational complexity. Furthermore, a feature fusion deep learning (FFDL) model is introduced to combine two types of features of lumbar vertebrae X-ray images, which uses sobel kernel and Gabor kernel to obtain the contour and texture of lumbar vertebrae, respectively. Comprehensive qualitative and quantitative experiments demonstrate that our proposed model performs more accurate in abnormal cases with pathologies and surgical implants in multi-angle views.

  11. Quantitative detection of Cucumber vein yellowing virus in susceptible and partially resistant plants using real-time PCR.

    PubMed

    Picó, Belén; Sifres, Alicia; Nuez, Fernando

    2005-09-01

    A method for the detection of Cucumber vein yellowing virus (CVYV) that combines reverse transcription with real-time PCR (SYBR((R)) Green chemistry) was developed using specific primers designed from a nucleotide sequence of the RNA polymerase gene (NIb) conserved among all the available CVYV strains. This method provided a linear assay over five to six orders of magnitude and reproducibly detected titres as low as 10(3) molecules of the target CVYV cDNA. Real-time PCR gave reproducible results for the quantification of CVYV in young leaves of susceptible and resistant cucumber landraces after mechanical inoculation. Significant differences in the starting amount of target cDNA were found between the analyzed genotypes, indicating differences in viral accumulation that correlated to their different levels of resistance. Real-time PCR results validated our previous findings using slot-blot hybridization, the dominance of the strong resistance to CVYV displayed by C.sat 10, and provided improved reliability and sensitivity of detection. This method has great potential in resistance breeding for germplasm screening, characterization of resistance mechanisms and genetic studies.

  12. 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.

  13. Partially hydrolyzed guar gum characterization and sensitive quantification in food matrices by high performance anion exchange chromatography with pulsed amperometric detection--validation using accuracy profile.

    PubMed

    Mercier, G; Campargue, C

    2012-11-02

    Interest concerning functional ingredients and especially dietary fibres has been growing in recent years. At the same time, the variety of ingredient accepted as dietary fibres and their mixing at low level in complex matrices have considerably complicated their quantitative analysis by approved AOAC methods. These reasons have led to the specific development of an innovative analytical method performed by high-performance anion-exchange chromatography (HPAEC) with pulsed amperometric detection (PAD) to detect and quantify partially hydrolyzed guar gum (PHGG) in fruit preparation and dairy matrices. The analytical methodology was divided in two steps which could be deployed separately or in conjunction. The first, consists in a complete characterization of PHGG by size exclusion chromatography (SEC) with multi-angle light scattering and refractive index detection and HPAEC-PAD to determine its physico-chemical properties and galactomannans content, and the second step is the development of a new HPAEC-PAD method for PHGG direct quantification in complex matrices (dairy product). Validation in terms of detection and quantification limits, linearity of the analytical range, average accuracy (recovery, trueness) and average uncertainty were statistically carried out with accuracy profile. Overall, this new chromatographic method has considerably improved the possibility to quantify without fractionation treatment, low level of dietary fibres emerging from specific galactomannans, in complex matrices and many foodstuffs.

  14. Sequential Two-Dimensional Partial Response Maximum Likelihood Detection Scheme with Constant-Weight Constraint Code for Holographic Data Storage Systems

    NASA Astrophysics Data System (ADS)

    Kong, Gyuyeol; Choi, Sooyong

    2012-08-01

    A sequential two-dimensional (2D) partial response maximum likelihood (PRML) detection scheme for holographic data storage (HDS) systems is proposed. We use two complexity reduction schemes, a reduced-state trellis and a constant-weight (CW) constraint. In the reduced-state trellis, the limited candidate bits surrounding the target bit are considered for the 2D PRML detector. In the CW constraint, the trellis transitions that violate the CW condition that each code-word block has only one white bit are eliminated. However, the 2D PRML detector using the complexity reduction schemes, which operates on 47 states and 169 branches, has performance degradation. To overcome performance degradation, a sequential detection algorithm uses the estimated a priori probability. By the sequential procedure, we mitigate 2D intersymbol interference with an enhanced reliability of the branch metric. Simulation results show that the proposed 2D PRML detection scheme yields about 3 dB gains over the one-dimensional PRML detection scheme.

  15. 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.

  16. 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.

  17. [Obesity and its respiratory effects detected through levels of partial pressure of carbon dioxide in the supine position].

    PubMed

    Sánchez-Medina, América; Sánchez-Medina, Marcela Ma

    Obesity is a disease that is closely associated with deleterious respiratory effects such as the Obesity Hypoventilation Syndrome which conventionally includes awake hypercapnia. There are studies addressing the detection of daytime hypercapnia with the patient either in sitting or standing position. However, there are no studies in obese subjects with a normal daytime PaCO2 in whom the detection of hypercapnia is made in the supine position. It is feasible that the physiopathological changes that occur in obese patients when they adopt the supine position lead to increased PaCO2 levels or hypercapnia. To determine the levels of PaCO2 in obese patients with a normal daytime PaCO2 in the supine position using arterial blood gas test. Fifty patients with BMI > 30 Kg/m², with a normal daytime PaCO2 were included. Daytime arterial blood gas test was performed first with the patient in a standing position along with pulmonary function test. A second arterial blood gas test was made 15 minutes after the patient adopted the supine position. Polisomnography was performed. Mean BMI was 40 kg/m2. PaCO2 levels in the standing position were less, statistically significant, than the PaCO2 levels in the supine position, 30.7 ± 2.5 mmHg vs 35.6 ± 6.7 mmH, p < 0.001. We can achieve an early detection of Obesity hipoventilation syndrome in obese patients with a normal daytime PaCO2 by performing the arterial blood gas test in the supine position before these patients develop severe complications.

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

    PubMed

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

    1984-12-01

    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.

  19. 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.

  20. 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.

  1. 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.

  2. Modified gravity black holes and their observable shadows

    NASA Astrophysics Data System (ADS)

    Moffat, J. W.

    2015-03-01

    The shadows cast by non-rotating and rotating modified gravity black holes are determined by the two parameters mass and angular momentum . The sizes of the shadows cast by the spherically symmetric static modified gravity-Schwarzschild and modified gravity-Kerr rotating black holes increase significantly as the free parameter is increased from zero. The Event Horizon Telescope shadow image measurements can determine whether Einstein's general relativity is correct or whether it should be modified in the presence of strong gravitational fields.

  3. Teardrop shadow of the pelvis: anatomy and clinical significance

    SciTech Connect

    Bowerman, J.W.; Sena, J.M.; Chang, R.

    1982-06-01

    The teardrop shadow of the pelvis is poorly understood and as a result its clinical significance is not appreciated. The structure responsible for this shadow was pinpointed by removing sections from the hemipelvis of an anatomic specimen with an electric saw. This structure is located in the anteroinferior portion of the acetabular fossa at the acetabular notch and consists of cortical and medullary bone contributed primarily from the ischium with a much smaller contribution from the superior pubic ramus. The normal and abnormal appearances of the teardrop shadow of the acetabulum of three patients were demonstrated on both plain radiographs and computed tomographic (CT) scans.

  4. More Efficient Virtual Shadow Maps for Many Lights.

    PubMed

    Olsson, Ola; Billeter, Markus; Sintorn, Erik; Kampe, Viktor; Assarsson, Ulf

    2015-06-01

    Recently, several algorithms have been introduced that enable real-time performance for many lights in applications such as games. In this paper, we explore the use of hardware-supported virtual cube-map shadows to efficiently implement high-quality shadows from hundreds of light sources in real time and within a bounded memory footprint. In addition, we explore the utility of ray tracing for shadows from many lights and present a hybrid algorithm combining ray tracing with cube maps to exploit their respective strengths. Our solution supports real-time performance with hundreds of lights in fully dynamic high-detail scenes.

  5. 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.

  6. Defect detection of partially complete SAW and TIG welds using the ultrasonic time-of-flight diffraction method

    NASA Astrophysics Data System (ADS)

    Lawson, Shaun W.; Bonser, Gary R.

    1998-03-01

    An application of machine vision applied to the analysis of ultrasonic images formed using the time-of-flight diffraction (TOFD) method on incomplete weld geometries is described. The rationale of the work being to identify weld defects as soon as they are produced, thereby reducing the costs of any subsequent repairs. The analysis uses TOFD scans as input to a filtering and 'window' based variance operator for the segmentation of suspect defect areas inside the weld region. A suite of pc based software and a high temperature TOFD data acquisition system have been benchmarked through a series of demonstration trials on both 80mm thick carbon steel submerged arc welded testpieces, and 25mm thick carbon steel tungsten inert gas welded testpieces. The range of intentionally implanted defects, from root cracks to lack of side wall fusion, were detected with an overall accuracy of 79 percent on a data set of 174 defects on scans performed at 10-90 percent weld completion.

  7. Rapid and direct detection of clostridium chauvoei by PCR of the 16S-23S rDNA spacer region and partial 23S rDNA sequences.

    PubMed

    Sasaki, Y; Yamamoto, K; Kojima, A; Tetsuka, Y; Norimatsu, M; Tamura, Y

    2000-12-01

    Clostridium chauvoei causes blackleg, which is difficult to distinguish from the causative clostridia of malignant edema. Therefore, a single-step PCR system was developed for specific detection of C. chauvoei DNA using primers derived from the 16S-23S rDNA spacer region and partial 23S rDNA sequences. The specificity of the single-step PCR system was demonstrated by testing 37 strains of clostridia and 3 strains of other genera. A 509 bp PCR product, which is a C. choauvoei-specific PCR product, could be amplified from all of the C. chauvoei strains tested, but not from the other strains. Moreover, this single-step PCR system specifically detected C. chauvoei DNA in samples of muscle from mice 24 hr after inoculation with 100 spores of C. chauvoei, and in clinical materials from a cow affected with blackleg. These results suggest that our single-step PCR system may be useful for direct detection of C. chauvoei in culture and in clinical materials from animals affected with blackleg.

  8. Detection of a true breeding homeotic gene mutant Pps-1 with partially petaloid sepals in opium poppy (Papaver somniferum L.) and its genetic behavior.

    PubMed

    Dhawan, Om Prakash; Dubey, Mukesh Kumar; Khanuja, Suman Preet Singh

    2007-01-01

    A spontaneous true breeding homeotic gene mutant Pps-1 with distinct partial petaloid sepals was detected in the population of downy mildew (DM)-resistant elite accession I-14 during our studies for the identification of disease resistance sources in opium poppy. The trait was found to be stable and inherited truly in the subsequent generations. Genetic studies were carried out through systematic reciprocal crosses with the parental wild-type genotype I-14, and segregation pattern of phenotypic characteristics in F(1) and F(2) populations clearly indicated single recessive nuclear gene control of the mutant character. The studies have demonstrated that the mutant phenotype is due to mutations at the Pps-1 locus that possibly corresponds to B-class function (according to ABC model) with negative control function. The mutant Pps-1 being single-whorl homeotic mutant might greatly help in providing insight into mechanisms of flower development in opium poppy.

  9. 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.

  10. 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.

  11. 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.

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

    NASA Image and Video Library

    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...

  13. 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

  14. Shadow Theater: A Way to Enrich a Reading Program.

    ERIC Educational Resources Information Center

    Nirgiotis, Nicholas

    1983-01-01

    Describes the "Folk Tales through Shadow Theater" reading-enrichment program unit, in which fifth-grade students search for stories, write scripts, and stage and present plays to an audience of their schoolmates. (RH)

  15. Using Shadows to Detect Targets In Synthetic Aperture Radar Imagery

    DTIC Science & Technology

    2009-03-01

    2.2.2 SAR Range and Cross Range Resolutions. The Projection-Slice Theo - rem provides a basis for discussing image resolution in SAR. If the radar...Radar: A Signal Processing Approach. Kluwer Academic Publishers Norwell, MA, USA, 1996. 12. Kersten, P.R., R.W. Jansen , K. Luc, and T.L. Ainsworth

  16. Optical Algorithm for Cloud Shadow Detection Over Water

    DTIC Science & Technology

    2013-02-01

    Ocean. Technol., vol. 24, no. 3, pp. 322-343, Mar. 2007. [16] S. A. Ackerman, K. I. Strabala, P. Menzel , R. A. Frey, C. C. Moeller, and L. E. Gumley...18] S. Plamick, M. D. King, S. A. Ackerman. W. P. Menzel , B. A. Baum. J. C. Riedi, and R. A. Frey, "The MODIS cloud products: Algorithms and examples...invariant color models," IEEE Trans. Geosci. Remote Sens., vol. 44, no. 6, pp. 1661-1671, Jun. 2006. [31] S. A. Ackerman, K. I. Strabala, P. Menzel

  17. A historical note on illusory contours in shadow writing.

    PubMed

    Vezzani, Stefano; Marino, Barbara F M

    2009-01-01

    It is widely accepted that illusory contours have been first displayed and discussed by Schumann (1900, Zeitschrift für Psychologie und Physiologie der Sinnesorgane 23 1-32). Here we show that, before him, Jastrow (1899, Popular Science Monthly 54 299-312) produced illusory contours consisting of a shadow word. A brief history of shadow writing in psychological literature from Jastrow to Brunswik is presented, in which the contributions of Pillsbury, Warren, Koffka, and Benussi are examined.

  18. Diagnostics in the shadow of HIV epidemics.

    PubMed

    Janossy, George; Mandy, Frank; O'Gorman, Maurice R G

    2008-01-01

    As part of the effort to promote elimination of global health care disparities, this special supplement compiled 19 articles about practical diagnostic cytometry to recognize the recent achievements of laboratory scientists working in the shadow of the HIV/AIDS epidemics in resource limited settings. First, the clinical significance, diagnostic utility (as governed by international guidelines), and the historical perspectives of CD4+ T cell enumeration are reviewed. Then successful large-scale implementations of cost-effective CD4 counting are described for parts of Africa, USA, and the Caribbean. These activities are linked with both the training of personnel in fledgling laboratories as well as with external quality assessment implementations. Some of the more recent solutions related to pediatric CD4 testing using CD4% values are covered. Nevertheless, the need for further simplification and parsimony is still immense, and the potential solutions are catalogued in the articles written by experts operating in truly challenging rural environments. Cytometry is considered to be an expandable flexible technology for other assays beyond CD4 assessment, particularly within organized laboratory services in the Third World. These include haematological measurements, CD38/CD8 lymphocyte activation for viral load-related assessments, diagnosis of active tuberculosis and malaria, and bead-based serological assays for a variety of infectious diseases. The development and support of these emerging technologies by affluent countries is not entirely altruistic but is likely to be beneficial for both the Third and the First Worlds. Copyright 2008 Clinical Cytometry Society.

  19. 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.

  20. '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.

  1. Light - Shadow Interactions in Italian Medieval Churches

    NASA Astrophysics Data System (ADS)

    Incerti, Manuela

    In the relationship between architecture and the sky, it is possible to identify three different design issues. The first regards the alignment of buildings with visible points on the horizon that coincide with the rising or setting of a celestial body (sun, planets, stars, or moon) on particular dates during the astronomical year (or liturgical year for sacred buildings). The second is the relationship between planimetric design and the design of the elevations. We are all familiar today with several "light effects", which sometimes have almost hierophanic characteristics that, on certain days of the year, were used to engross, captivate, and amaze the spectator. Contrary to the first two issues, the third comes after the design and building stages and concerns the question of decorative elements. It is reasonable to believe that many years after the works were terminated, certain wall finishings were chosen over others, such as painted frescoes or statues. Whoever did this was fully aware, thanks to direct observation, that such decoration would be struck by a single ray of light on a specific day. This chapter examines light-shadow interactions in some Italian medieval churches.

  2. Smartphone based Tomographic PIV using colored shadows

    NASA Astrophysics Data System (ADS)

    Aguirre-Pablo, Andres A.; Alarfaj, Meshal K.; Li, Er Qiang; Thoroddsen, Sigurdur T.

    2016-11-01

    We use low-cost smartphones and Tomo-PIV, to reconstruct the 3D-3C velocity field of a vortex ring. The experiment is carried out in an octagonal tank of water with a vortex ring generator consisting of a flexible membrane enclosed by a cylindrical chamber. This chamber is pre-seeded with black polyethylene microparticles. The membrane is driven by an adjustable impulsive air-pressure to produce the vortex ring. Four synchronized smartphone cameras, of 40 Mpx each, are used to capture the location of particles from different viewing angles. We use red, green and blue LED's as backlighting sources, to capture particle locations at different times. The exposure time on the smartphone cameras are set to 2 seconds, while exposing each LED color for about 80 μs with different time steps that can go below 300 μs. The timing of these light pulses is controlled with a digital delay generator. The backlight is blocked by the instantaneous location of the particles in motion, leaving a shadow of the corresponding color for each time step. The image then is preprocessed to separate the 3 different color fields, before using the MART reconstruction and cross-correlation of the time steps to obtain the 3D-3C velocity field. This proof of concept experiment represents a possible low-cost Tomo-PIV setup.

  3. Shadow imaging in bubbly gas-liquid two-phase flow in porous structures

    NASA Astrophysics Data System (ADS)

    Altheimer, Marco; Häfeli, Richard; Wälchli, Carmen; Rudolf von Rohr, Philipp

    2015-09-01

    Shadow imaging is used for the investigation of bubbly gas-liquid two-phase flow in a porous structure. The porous structure is made of Somos WaterShed XC 11122, a clear epoxy resin used in rapid prototyping. Optical access is provided by using an aqueous solution of sodium iodide and zinc iodide having the same refractive index as the structure material (). Nitrogen is injected into the continuous phase at volumetric transport fractions in the range of resulting in a hold-up of . The obtained images of overlapping bubble shadows are processed to measure the bubble dimensions. Therefore, a new processing sequence is developed to determine bubble dimensions from overlapping bubble shadows by ellipse fitting. The accuracy of the bubble detection and sizing routine is assessed processing synthetic images. It is shown that the developed technique is suitable for volumetric two-phase flow measurements. Important global quantities such as gas hold-up and total interfacial area can be measured with only one camera. Operation parameters for gas-liquid two-phase flows are determined to improve mass and heat transfer between the phases.

  4. Characterizing magnetopause shadowing effects in the outer electron radiation belt during geomagnetic storms

    NASA Astrophysics Data System (ADS)

    Herrera, D.; Maget, V. F.; Sicard-Piet, A.

    2016-10-01

    Relativistic electrons dynamics is still challenging to predict during the main phase of a storm. In particular, three dimensions radiation belt models, for which temporal resolution is limited, fail in predicting their behavior, especially when dropouts occur. In this paper we present a new model of magnetopause shadowing losses to be incorporated into the ONERA Salammbô code in order to improve the model accuracy. We show in this paper that above a few hundred keVs, magnetopause shadowing is the first contribution to losses in the outer electron belt during dropout events. Global variations of Earth-magnetopause distance and relativistic electron flux have been analyzed to establish the correlation between the magnetopause shadowing and dropouts on the outer electron radiation belt during geomagnetic storms. To that purpose, a Superposed Epoch Analysis has been done using NOAA Polar-orbiting Operational Environmental Satellite 15 measurements. First, a list of 67 Stream Interfaces has been used to validate the method, and then the Superposed Epoch Analysis has been run over more than one solar cycle. Our results show that the model of magnetopause location we have developed fits well with a Superposed Epoch Analysis performed and that we are able to define a criteria based on it that detect intense dropouts. Finally, we have included this model in the Salammbô code, and we present here the improvements obtained as well as the validation made.

  5. Training Classifiers with Shadow Features for Sensor-Based Human Activity Recognition

    PubMed Central

    Fong, Simon; Song, Wei; Cho, Kyungeun; Wong, Raymond; Wong, Kelvin K. L.

    2017-01-01

    In this paper, a novel training/testing process for building/using a classification model based on human activity recognition (HAR) is proposed. Traditionally, HAR has been accomplished by a classifier that learns the activities of a person by training with skeletal data obtained from a motion sensor, such as Microsoft Kinect. These skeletal data are the spatial coordinates (x, y, z) of different parts of the human body. The numeric information forms time series, temporal records of movement sequences that can be used for training a classifier. In addition to the spatial features that describe current positions in the skeletal data, new features called ‘shadow features’ are used to improve the supervised learning efficacy of the classifier. Shadow features are inferred from the dynamics of body movements, and thereby modelling the underlying momentum of the performed activities. They provide extra dimensions of information for characterising activities in the classification process, and thereby significantly improve the classification accuracy. Two cases of HAR are tested using a classification model trained with shadow features: one is by using wearable sensor and the other is by a Kinect-based remote sensor. Our experiments can demonstrate the advantages of the new method, which will have an impact on human activity detection research. PMID:28264470

  6. Objects Versus Shadows as Influences on Perceived Object Motion

    PubMed Central

    Kingdom, Frederick A. A.

    2016-01-01

    The motion trajectory of an object’s cast shadow has been shown to alter the perceived trajectory of a casting object, an effect that holds even if the cast shadow appears unrealistic. This raises the question of whether a cast shadow per se is necessary for this influence, a question that has been studied only with stationary targets. We examined the relative influence of a shadow and a spherical object on the perceived motion trajectory of an identical spherical object, using a paradigm similar to Kersten, Mamassian, and Knill's ball-in-box animation. We recorded both depth and height estimates of the perceived end-point of the target trajectory as a function of various target and context trajectories. Both shadows and objects significantly influenced the perceived trajectory of the target, though the influence of the shadow was overall stronger. We conjecture that the influence of the object reveals the assumption that similar objects moving at the same speed and in similar directions are perceived to move within the same plane, a plane subject to a fronto-parallel bias. PMID:28096972

  7. 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

  8. Objects Versus Shadows as Influences on Perceived Object Motion.

    PubMed

    Ouhnana, Marouane; Kingdom, Frederick A A

    2016-01-01

    The motion trajectory of an object's cast shadow has been shown to alter the perceived trajectory of a casting object, an effect that holds even if the cast shadow appears unrealistic. This raises the question of whether a cast shadow per se is necessary for this influence, a question that has been studied only with stationary targets. We examined the relative influence of a shadow and a spherical object on the perceived motion trajectory of an identical spherical object, using a paradigm similar to Kersten, Mamassian, and Knill's ball-in-box animation. We recorded both depth and height estimates of the perceived end-point of the target trajectory as a function of various target and context trajectories. Both shadows and objects significantly influenced the perceived trajectory of the target, though the influence of the shadow was overall stronger. We conjecture that the influence of the object reveals the assumption that similar objects moving at the same speed and in similar directions are perceived to move within the same plane, a plane subject to a fronto-parallel bias.

  9. 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.

  10. 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.

  11. Building Detection in SAR Imagery

    SciTech Connect

    Steinbach, Ryan Matthew; Koch, Mark William; Moya, Mary M; Goold, Jeremy

    2014-08-01

    Current techniques for building detection in Synthetic Aperture Radar (SAR) imagery can be computationally expensive and/or enforce stringent requirements for data acquisition. The desire is to present a technique that is 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 technique assumes 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. Constraints based on angle of depression and the relationship between connected bright lines and shadows are applied to remove unrelated arcs. Once the related bright lines and shadows are grouped, their locations are combined to provide an approximate building location. Experimental results are provided showing the outcome of the technique.

  12. 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.

  13. 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

  14. [Molecular identification and detection of moon jellyfish (Aurelia sp.) based on partial sequencing of mitochondrial 16S rDNA and COI].

    PubMed

    Wang, Jian-Yan; Zhen, Yu; Wang, Guo-shan; Mi, Tie-Zhu; Yu, Zhi-gang

    2013-03-01

    Taking the moon jellyfish Aurelia sp. commonly found in our coastal sea areas as test object, its genome DNA was extracted, the partial sequences of mt-16S rDNA (650 bp) and mt-COI (709 bp) were PCR-amplified, and, after purification, cloning, and sequencing, the sequences obtained were BLASTn-analyzed. The sequences of greater difference with those of the other jellyfish were chosen, and eight specific primers for the mt-16S rDNA and mt-COI of Aurelia sp. were designed, respectively. The specificity test indicated that the primer AS3 for the mt-16S rDNA and the primer AC3 for the mt-COI were excellent in rapidly detecting the target jellyfish from Rhopilema esculentum, Nemopilema nomurai, Cyanea nozakii, Acromitus sp., and Aurelia sp., and thus, the techniques for the molecular identification and detection of moon jellyfish were preliminarily established, which could get rid of the limitations in classical morphological identification of Aurelia sp. , being able to find the Aurelia sp. in the samples more quickly and accurately.

  15. Saturn's rings thickness with the shadow hiding

    NASA Astrophysics Data System (ADS)

    Deau, Estelle; Brahic, André; Porco, Carolyn

    Using the Hapke shadow hiding model on various curves phases of ISS/Cassini, we were able to compute the thickness of Saturn's rings through the photometric filling factor. Our results show that diffuse rings (C ring and Cassini Division) are distributed in a monolayer with a thickness from a few centimeters to 5 meters. This seems to suggest that the layer is smaller than the larger particles. For the A and B rings, we find a thickness ranging from 10 to 20 meters, then leading to multiple layers of particles. Our results for the A ring are systematically lower than the values derived by density waves (Tiscareno et al., 2007) and dynamical simulations of Salo and Kaarjalainen (2003). For the first one, this can be explain by the fact the vertical height of the density waves are the upper limit of the real height. Indeed, the wakes (Julian & Toomre, 1966; Salo 1995) conduce the viscosity in the A ring (Daisaka et al., 2001), and produce random speeds greater in the ring plane than in the vertical direction (Daisaka & Ida, 1999), thereby reducing the thickness given by the vertical random speed used to compute the vertical height. However, for the latter one, simulations lead in all the cases (A and B rings such as C ring and Cassini Division) to vertical height of few meters. This constancy can be explained by the fact that simulations take a size distribution too truncated, and a coefficient of restitution rather simple (indeed, rings reflect different surface conditions related to the optical depth, thus the Bridges' law could not promote only one type of collisions). Finally, our results prefer monolayer (layer smaller than the larger particles which allow multilayer of smaller particules) for the faint rings (C ring and Cassini Division) and multilayer for the A and B rings.

  16. A DNA fragment from the human X chromosome short arm which detects a partially homologous sequence on the Y chromosomes long arm.

    PubMed Central

    Koenig, M; Camerino, G; Heilig, R; Mandel, J L

    1984-01-01

    An X linked human DNA fragment (named DXS31 ) which detects partially homologous sequences on the Y chromosome has been isolated. Regional localisation of the two sex linked sequences was determined using a panel of rodent-human somatic cell hybrids. The X specific sequence is located at the tip of the short arm ( Xp22 .3-pter), i.e. within or close to the region which pairs with the Y chromosome short arm at meiosis. However the Y specific sequence is located in the heterochromatic region of the long arm ( Yq11 -qter) and lies outside from the pairing region. DNAs from several XX male subjects were probed with DXS31 and in all cases a double dose of the X linked fragment was found, and the Y specific fragment was absent. DXS31 detects in chimpanzee a male-female differential pattern identical to that found in man. However results obtained in a more distantly related species, the brown lemur, suggest that the sequences detected by DXS31 in this species might be autosomally coded. The features observed with these X-Y related sequences do not fit with that expected from current hypotheses of homology between the pairing regions of the two sex chromosomes, nor with the pattern observed with other X-Y homologous sequences recently characterized. Our results suggest also that the rule of conservation of X linkage in mammals might not apply to sequences present on the tip of the X chromosome short arm, in bearing with the controversial issue of steroid sulfatase localisation in mouse. Images PMID:6728677

  17. 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.

  18. 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.

  19. Doctoring Undercover: updating the educational tradition of shadowing

    PubMed Central

    Clark, Claire D.

    2017-01-01

    ABSTRACT Background: Premedical students are educated in basic biological and health sciences. As a complement to traditional premedical coursework, medical school applicants are encouraged to shadow practitioners, with the hope that observation will introduce students to the culture and practice of healthcare. Yet the shadowing experience varies widely across practitioners and institutions; resources that guide students’ critical reflection and structure the experience are scarce. Development: A pilot experiential learning course, Doctoring Undercover: Shadowing and the Culture of Medicine, was developed to fill this gap. The course consisted of three parts: an introduction to medical culture through the disciplines of medical sociology, history, anthropology, and bioethics; a site placement in which students applied these fields’ analytical techniques to the study of medical culture and practice; and the development of an online activity guide that other premedical students may adapt to their shadowing circumstances. Implementation: Students reported that they were exposed to new disciplinary perspectives and interprofessional environments that they would not traditionally encounter. Students’ contributions to the shadowing guide encouraged active learning and reflection on the dynamics of effective patient-provider relationships and shadowing experiences. Future Directions: Locally, the class may be scaled for a larger group of premedical students and incorporated into a formal pathway program for premedical students; the content will also be integrated into the clinical medicine course for first-year medical students. Online, the guide will be promoted for use by other institutions and by individuals planning extracurricular shadowing experiences; feedback will be solicited. Tools for evaluating the short- and long-term impact of the course and guide will be developed and validated. Observational and experimental studies of the course’s impact should be

  20. 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.

  1. 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.

  2. Chasing Shadows: Rotation of the Azimuthal Asymmetry in the TW Hya Disk

    NASA Astrophysics Data System (ADS)

    Debes, John H.; Poteet, Charles A.; Jang-Condell, Hannah; Gaspar, Andras; Hines, Dean; Kastner, Joel H.; Pueyo, Laurent; Rapson, Valerie; Roberge, Aki; Schneider, Glenn; Weinberger, Alycia J.

    2017-02-01

    We have obtained new images of the protoplanetary disk orbiting TW Hya in visible, total intensity light with the Space Telescope Imaging Spectrograph (STIS) on the Hubble Space Telescope (HST), using the newly commissioned BAR5 occulter. These HST/STIS observations achieved an inner working angle of ∼0.″2, or 11.7 au, probing the system at angular radii coincident with recent images of the disk obtained by ALMA and in polarized intensity near-infrared light. By comparing our new STIS images to those taken with STIS in 2000 and with NICMOS in 1998, 2004, and 2005, we demonstrate that TW Hya’s azimuthal surface brightness asymmetry moves coherently in position angle. Between 50 au and 141 au we measure a constant angular velocity in the azimuthal brightness asymmetry of 22.°7 yr‑1 in a counterclockwise direction, equivalent to a period of 15.9 yr assuming circular motion. Both the (short) inferred period and lack of radial dependence of the moving shadow pattern are inconsistent with Keplerian rotation at these disk radii. We hypothesize that the asymmetry arises from the fact that the disk interior to 1 au is inclined and precessing owing to a planetary companion, thus partially shadowing the outer disk. Further monitoring of this and other shadows on protoplanetary disks potentially opens a new avenue for indirectly observing the sites of planet formation. Based on observations made with the NASA/ESA Hubble Space Telescope, obtained from the data archive at the Space Telescope Science Institute. STScI is operated by the Association of Universities for Research in Astronomy, Inc., under NASA contract NAS 5-26555.

  3. 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.

  4. Partial Tonsillectomy.

    PubMed

    Wong, Kevin; Levi, Jessica R

    2017-03-01

    Evaluate the content and readability of health information regarding partial tonsillectomy. A web search was performed using the term partial tonsillectomy in Google, Yahoo!, and Bing. The first 50 websites from each search were evaluated using HONcode standards for quality and content. Readability was assessed using the Flesch-Kincaid Grade Level (FKGL), Flesch Reading Ease, Gunning-Fog Index, Coleman-Liau Index, Automated Readability Index, and SMOG score. The Freeman-Halton extension of Fisher's exact test was used to compare categorical differences between engines. Less than half of the websites mentioned patient eligibility criteria (43.3%), referenced peer-reviewed literature (43.3%), or provided a procedure description (46.7%). Twenty-two websites (14.7%) were unrelated to partial tonsillectomy, and over half contained advertisements (52%). These finding were consistent across search engines and search terms. The mean FKGL was 11.6 ± 0.11, Gunning-Fog Index was 15.1 ± 0.13, Coleman-Liau Index was 14.6 ± 0.11, ARI was 12.9 ± 0.13, and SMOG grade was 14.0 ± 0.1. All readability levels exceeded the abilities of the average American adult. Current online information regarding partial tonsillectomy may not provide adequate information and may be written at a level too difficult for the average adult reader.

  5. 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.

  6. 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

  7. Shadows of Kerr Black Holes with Scalar Hair

    NASA Astrophysics Data System (ADS)

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

    2015-11-01

    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.

  8. Moon and Sun shadowing effect in the MACRO detector

    NASA Astrophysics Data System (ADS)

    Ambrosio, M.; Antolini, R.; Baldini, A.; Barbarino, G. C.; Barish, B. C.; Battistoni, G.; Becherini, Y.; Bellotti, R.; Bemporad, C.; Bernardini, P.; Bilokon, H.; Bower, C.; Brigida, M.; Bussino, S.; Cafagna, F.; Calicchio, M.; Campana, D.; Carboni, M.; Caruso, R.; Cecchini, S.; Cei, F.; Chiarella, V.; Chiarusi, T.; Choudhary, B. C.; Coutu, S.; Cozzi, M.; De Cataldo, G.; Dekhissi, H.; De Marzo, C.; De Mitri, I.; Derkaoui, J.; De Vincenzi, M.; Di Credico, A.; Erriquez, O.; Favuzzi, C.; Forti, C.; Fusco, P.; Giacomelli, G.; Giannini, G.; Giglietto, N.; Giorgini, M.; Grassi, M.; Grillo, A.; Gustavino, C.; Habig, A.; Hanson, K.; Heinz, R.; Katsavounidis, E.; Katsavounidis, I.; Kearns, E.; Kim, H.; Kumar, A.; Kyriazopoulou, S.; Lamanna, E.; Lane, C.; Levin, D. S.; Lipari, P.; Longley, N. P.; Longo, M. J.; Loparco, F.; Maaroufi, F.; Mancarella, G.; Mandrioli, G.; Manzoor, S.; Margiotta, A.; Marini, A.; Martello, D.; Marzari-Chiesa, A.; Mazziotta, M. N.; Michael, D. G.; Monacelli, P.; Montaruli, T.; Monteno, M.; Mufson, S.; Musser, J.; Nicolò, D.; Nolty, R.; Orth, C.; Osteria, G.; Palamara, O.; Patrizii, L.; Pazzi, R.; Peck, C. W.; Perrone, L.; Petrera, S.; Popa, V.; Rainò, A.; Reynoldson, J.; Ronga, F.; Satriano, C.; Scapparone, E.; Scholberg, K.; Sioli, M.; Sirri, G.; Sitta, M.; Spinelli, P.; Spinetti, M.; Spurio, M.; Steinberg, R.; Stone, J. L.; Sulak, L. R.; Surdo, A.; Tarlè, G.; Togo, V.; Vakili, M.; Walter, C. W.; Webb, R.

    2003-11-01

    Using data collected by the MACRO experiment from 1989 to the end of its operations in 2000, we have studied in the underground muon flux the shadowing effects due to both the Moon and the Sun. We have observed the shadow cast by the Moon at its apparent position with a significance of 6.5 σ. The Moon shadowing effect has been used to verify the pointing capability of the detector and to determine the instrument resolution for the search of muon excesses from any direction of the celestial sphere. The dependence of the effect on the geomagnetic field is clearly shown by splitting the data sample in day and night observations. The Sun shadow, observed with a significance of 4.6 σ is displaced by about 0.6° from its apparent position. In this case however the explanation resides in the configuration of the Solar and Interplanetary Magnetic Fields, which affect the propagation of cosmic ray particles between the Sun, and the Earth. The displacement of the Sun shadow with respect to the real Sun position has been used to establish an upper limit on the antimatter flux in cosmic rays of about 48% at 68% c.l. and primary energies of about 20 TeV.

  9. Using shadow page cache to improve isolated drivers performance.

    PubMed

    Zheng, Hao; Dong, Xiaoshe; Wang, Endong; Chen, Baoke; Zhu, Zhengdong; Liu, Chengzhe

    2015-01-01

    With the advantage of the reusability property of the virtualization technology, users can reuse various types and versions of existing operating systems and drivers in a virtual machine, so as to customize their application environment. In order to prevent users' virtualization environments being impacted by driver faults in virtual machine, Chariot examines the correctness of driver's write operations by the method of combining a driver's write operation capture and a driver's private access control table. However, this method needs to keep the write permission of shadow page table as read-only, so as to capture isolated driver's write operations through page faults, which adversely affect the performance of the driver. Based on delaying setting frequently used shadow pages' write permissions to read-only, this paper proposes an algorithm using shadow page cache to improve the performance of isolated drivers and carefully study the relationship between the performance of drivers and the size of shadow page cache. Experimental results show that, through the shadow page cache, the performance of isolated drivers can be greatly improved without impacting Chariot's reliability too much.

  10. 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).

  11. A separable shadow Hamiltonian hybrid Monte Carlo method.

    PubMed

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

    2009-11-07

    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).

  12. Tropospheric turbulence in the Antarctic region and the shadow bands

    NASA Astrophysics Data System (ADS)

    Vats, Hari

    The troposphere contains turbulence which scatters light passing through the same. In this paper the phenomenon of shadow bands is explained to be due to the scattering of Sun light by the turbulence present in the local atmosphere. One such interesting observation of shadow bands was made possible just before and just after the total solar eclipse (TSE) on 23 November 2003 at Indian Antarctic station near Maitri. Here the formation and observations of shadow bands thus recorded during this TSE are presented. The results of correlation analysis show that the correlation falls to half (1) at separation of 35 cm in horizontal direction; and (2) also at 100 ms. time lag. The power spectrum of the shadow band fluctuations is observed to have a power law distribution (spectral index -2) which is different than the earlier eclipse observations reported in the literature. This is indicative of the fact that either the tropospheric turbulence in the Antarctic region is different than the other regions or the geometry of the present eclipse make the spectral index so different. However, it resembles closely with the theoretical predictions of the extended screen scintillation theory. Here a shadow band experiment proposed to be conducted during the total solar eclipse of 1 August 2008 will be presented.

  13. Observing shadow motions: resonant activity within the observer's motor system?

    PubMed

    Alaerts, Kaat; Van Aggelpoel, Tinne; Swinnen, Stephan P; Wenderoth, Nicole

    2009-09-25

    Several studies have demonstrated that the human motor cortex is activated by the mere observation of actions performed by others. In the present study, we explored whether the perception of 'impoverished motion stimuli', such as shadow animations, is sufficient to activate motor areas. To do so, transcranial magnetic stimulation (TMS) was applied over the hand area of the primary motor cortex (M1) while subjects observed shadow animations depicting finger motions. Data showed that resonant motor responses in M1 were only found when a biological effector was recognized from the observed shadow animation. Interestingly, M1 responses were similar for observing shadow or real motions. Therefore, the loss of 'pictorial' movement features in a shadow animation appeared to have no effect on motor resonance in M1. In summary, these findings suggest that the 'recognition' of biological motion from sparse visual input is both necessary and sufficient to recruit motor areas. This supports the hypothesis that the motor system is involved in recognizing the actions performed by others.

  14. Illumination invariance and shadow compensation via spectro-polarimetry technique

    NASA Astrophysics Data System (ADS)

    Ibrahim, Izzati; Yuen, Peter; Hong, Kan; Chen, Tong; Soori, Umair; Jackman, James; Richardson, Mark

    2012-10-01

    A major problem for obtaining target reflectance via hyperspectral imaging systems is the presence of illumination and shadow effects. These factors are common artefacts, especially when dealing with a hyperspectral imaging system that has sensors in the visible to near infrared region. This region is known to have highly scattered and diffuse radiance that can modify the energy recorded by the imaging system. A shadow effect will lower the target reflectance values due to the small radiant energy impinging on the target surface. Combined with illumination artefacts, such as diffuse scattering from the surrounding targets, background or environment, the shape of the shadowed target reflectance will be altered. We propose a new method to compensate for illumination and shadow effects on hyperspectral imageries by using a polarization technique. This technique, called spectro-polarimetry, estimates the direct and diffuse irradiance based on two images taken with and without a polarizer. The method is then evaluated using a spectral similarity measure, angle and distance metric. The results of indoor and outdoor tests have shown that using the spectro-polarimetry technique can improve the spectral constancy between shadow and full illumination spectra.

  15. 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/

  16. Simultaneous cast shadows, illumination and geometry inference using hypergraphs.

    PubMed

    Panagopoulos, Alexandros; Wang, Chaohui; Samaras, Dimitris; Paragios, Nikos

    2013-02-01

    The cast shadows in an image provide important information about illumination and geometry. In this paper, we utilize this information in a novel framework in order to jointly recover the illumination environment, a set of geometry parameters, and an estimate of the cast shadows in the scene given a single image and coarse initial 3D geometry. We model the interaction of illumination and geometry in the scene and associate it with image evidence for cast shadows using a higher order Markov Random Field (MRF) illumination model, while we also introduce a method to obtain approximate image evidence for cast shadows. Capturing the interaction between light sources and geometry in the proposed graphical model necessitates higher order cliques and continuous-valued variables, which make inference challenging. Taking advantage of domain knowledge, we provide a two-stage minimization technique for the MRF energy of our model. We evaluate our method in different datasets, both synthetic and real. Our model is robust to rough knowledge of geometry and inaccurate initial shadow estimates, allowing a generic coarse 3D model to represent a whole class of objects for the task of illumination estimation, or the estimation of geometry parameters to refine our initial knowledge of scene geometry, simultaneously with illumination estimation.

  17. Using Shadow Page Cache to Improve Isolated Drivers Performance

    PubMed Central

    Dong, Xiaoshe; Wang, Endong; Chen, Baoke; Zhu, Zhengdong; Liu, Chengzhe

    2015-01-01

    With the advantage of the reusability property of the virtualization technology, users can reuse various types and versions of existing operating systems and drivers in a virtual machine, so as to customize their application environment. In order to prevent users' virtualization environments being impacted by driver faults in virtual machine, Chariot examines the correctness of driver's write operations by the method of combining a driver's write operation capture and a driver's private access control table. However, this method needs to keep the write permission of shadow page table as read-only, so as to capture isolated driver's write operations through page faults, which adversely affect the performance of the driver. Based on delaying setting frequently used shadow pages' write permissions to read-only, this paper proposes an algorithm using shadow page cache to improve the performance of isolated drivers and carefully study the relationship between the performance of drivers and the size of shadow page cache. Experimental results show that, through the shadow page cache, the performance of isolated drivers can be greatly improved without impacting Chariot's reliability too much. PMID:25815373

  18. 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].

  19. 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}.

  20. 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.

  1. Detection of inborn errors of metabolism utilizing GC-MS urinary metabolomics coupled with a modified orthogonal partial least squares discriminant analysis.

    PubMed

    Yang, Qin; Lin, Shan-Shan; Yang, Jiang-Tao; Tang, Li-Juan; Yu, Ru-Qin

    2017-04-01

    GC-MS urinary metabolomic analysis coupled with chemometrics is used to detect inborn errors of metabolism (IEMs), which are genetic disorders causing severe mental and physical debility and even sudden infant death. Orthogonal partial least squares discriminant analysis (OPLS-DA) is an efficient multivariate statistical method that conducts data analysis of metabolite profiling. However, performance degradation is often observed for OPLS-DA due to increasing size and complexity of metabolomic datasets. In this study, hybrid particle swarm optimization (HPSO) is employed to modify OPLS-DA by simultaneously selecting the optimal variable subset, associated weights and the appropriate number of orthogonal components, constructing a new algorithm called HPSO-OPLSDA. Investigating two IEMs, methylmalonic acidemia (MMA) and isovaleric acidemia (IVA), results suggest that HPSO-OPLSDA can significantly outperform OPLS-DA in terms of the discrimination between disease samples and healthy controls. Moreover, main discriminative metabolites are identified by HPSO-OPLSDA to aid the clinical diagnosis of IEMs, including methylmalonic-2, methylcitric-4(1) and 3-OH-propionic-2 for MMA and isovalerylglycine-1 for IVA.

  2. 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.

  3. 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.

  4. 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.

  5. Self-shadowing in ballistic fan formation from point seeds

    NASA Astrophysics Data System (ADS)

    Pelliccione, M.; Lu, T.-M.

    2007-06-01

    We utilize the model of ballistic aggregation to investigate the growth of particles on a point seed under various oblique particle fluxes to model nanorod growth at early deposition times. In particular, we show that the angular nature of the particle flux leads to a self-shadowing behavior, where features of an individual aggregate can shadow other features of the same aggregate. We quantify the shape of the aggregates by the growth exponent p , where the radius of the aggregate R is related to the height of the aggregate z as Rtilde zp . We show that the self-shadowing effect is the dominant factor that controls the evolution of nanorod size during oblique angle deposition. The simulation predictions are consistent with recent experimental results.

  6. 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

  7. 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.

  8. 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.

  9. New uses of shadow enhancement. [in geological mapping

    NASA Technical Reports Server (NTRS)

    Sawatzky, D. L.; Lee, K.

    1974-01-01

    Shadow enhancement of topographic linears in photographic or scanner images is a valuable tool for interpretation of geologic structures. Whether linears will be enhanced or subdued depends on sun angle and azimuth. The relationship of the sun's attitude to topographic slopes determines which trends are available for interpretation in existing imagery, and it can be used to select the time of day, surface properties, and film and filter characteristics in planning aircraft flights or satellite orbital passes. The technique of selective shadow enhancement can be applied to all photographic or imaging experiments, but is best for snow-covered scenes, side-looking radar images, and painted relief models.

  10. 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.

  11. 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.

  12. Near-wall velocity measurements by particle-shadow tracking

    NASA Astrophysics Data System (ADS)

    Lancien, Pierre; Lajeunesse, Éric; Métivier, François

    2007-06-01

    We report a new method to measure the velocity of a fluid in the vicinity of a wall. The method, that we call particle-shadow tracking (PST), simply consists in seeding the fluid with a small number of fine tracer particles of density close to that of the fluid. The position of each particle and of its shadow on the wall are then tracked simultaneously, allowing one to accurately determine the distance separating tracers from the wall and therefore to extract the velocity field. We present an application of the method to the determination of the velocity profile inside a laminar density current flowing along an inclined plane.

  13. 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.

  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. 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.

  16. Evolution of broadly cross-reactive HIV-1-neutralizing activity: therapy-associated decline, positive association with detectable viremia, and partial restoration of B-cell subpopulations.

    PubMed

    Ferreira, Carolina B; Merino-Mansilla, Alberto; Llano, Anuska; Pérez, Ignacio; Crespo, Isabel; Llinas, Laia; Garcia, Felipe; Gatell, Jose M; Yuste, Eloisa; Sanchez-Merino, Victor

    2013-11-01

    Little is known about the stability of HIV-1 cross-neutralizing responses. Taking into account the fact that neutralization breadth has been positively associated with plasma viral load, there is no explanation for the presence of broadly neutralizing responses in a group of patients on treatment with undetectable viremia. In addition, the B-cell profile responsible for broadly cross-neutralizing responses is unknown. Here we studied the evolution of neutralizing responses and the B-cell subpopulation distribution in a group of patients with broadly cross-reactive HIV-1-neutralizing activity. We studied neutralization breadth evolution in a group of six previously identified broadly cross-neutralizing patients and six control patients during a 6-year period with a previously described minipanel of recombinant viruses from five different subtypes. B-cell subpopulation distribution during the study was also determined by multiparametric flow cytometry. Broadly cross-neutralizing activity was transient in four broad cross-neutralizers and stable, up to 4.6 years, in the other two. In four out of five broad cross-neutralizers who initiated treatment, a neutralization breadth loss occurred after viremia had been suppressed for as much as 20 months. B-cell subpopulation analyses revealed a significant increase in the frequency of naive B cells in broadly cross-reactive samples, compared with samples with less neutralization breadth (increased from 44% to 62%). We also observed a significant decrease in tissue-like and activated memory B cells (decreased from 19% to 12% and from 17% to 9%, respectively). Our data suggest that HIV-1 broadly cross-neutralizing activity is variable over time and associated with detectable viremia and partial B-cell restoration.

  17. Evolution of Broadly Cross-Reactive HIV-1-Neutralizing Activity: Therapy-Associated Decline, Positive Association with Detectable Viremia, and Partial Restoration of B-Cell Subpopulations

    PubMed Central

    Ferreira, Carolina B.; Merino-Mansilla, Alberto; Llano, Anuska; Pérez, Ignacio; Crespo, Isabel; Llinas, Laia; Garcia, Felipe; Gatell, Jose M.; Yuste, Eloisa

    2013-01-01

    Little is known about the stability of HIV-1 cross-neutralizing responses. Taking into account the fact that neutralization breadth has been positively associated with plasma viral load, there is no explanation for the presence of broadly neutralizing responses in a group of patients on treatment with undetectable viremia. In addition, the B-cell profile responsible for broadly cross-neutralizing responses is unknown. Here we studied the evolution of neutralizing responses and the B-cell subpopulation distribution in a group of patients with broadly cross-reactive HIV-1-neutralizing activity. We studied neutralization breadth evolution in a group of six previously identified broadly cross-neutralizing patients and six control patients during a 6-year period with a previously described minipanel of recombinant viruses from five different subtypes. B-cell subpopulation distribution during the study was also determined by multiparametric flow cytometry. Broadly cross-neutralizing activity was transient in four broad cross-neutralizers and stable, up to 4.6 years, in the other two. In four out of five broad cross-neutralizers who initiated treatment, a neutralization breadth loss occurred after viremia had been suppressed for as much as 20 months. B-cell subpopulation analyses revealed a significant increase in the frequency of naive B cells in broadly cross-reactive samples, compared with samples with less neutralization breadth (increased from 44% to 62%). We also observed a significant decrease in tissue-like and activated memory B cells (decreased from 19% to 12% and from 17% to 9%, respectively). Our data suggest that HIV-1 broadly cross-neutralizing activity is variable over time and associated with detectable viremia and partial B-cell restoration. PMID:24006439

  18. 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. Copyright © 2016 Elsevier B.V. All rights reserved.

  19. High dynamic spectroscopy using a digital micromirror device and periodic shadowing.

    PubMed

    Kristensson, Elias; Ehn, Andreas; Berrocal, Edouard

    2017-01-09

    We present an optical solution called DMD-PS to boost the dynamic range of 2D imaging spectroscopic measurements up to 22 bits by incorporating a digital micromirror device (DMD) prior to detection in combination with the periodic shadowing (PS) approach. In contrast to high dynamic range (HDR), where the dynamic range is increased by recording several images at different exposure times, the current approach has the potential of improving the dynamic range from a single exposure and without saturation of the CCD sensor. In the procedure, the spectrum is imaged onto the DMD that selectively reduces the reflection from the intense spectral lines, allowing the signal from the weaker lines to be increased by a factor of 28 via longer exposure times, higher camera gains or increased laser power. This manipulation of the spectrum can either be based on a priori knowledge of the spectrum or by first performing a calibration measurement to sense the intensity distribution. The resulting benefits in detection sensitivity come, however, at the cost of strong generation of interfering stray light. To solve this issue the Periodic Shadowing technique, which is based on spatial light modulation, is also employed. In this proof-of-concept article we describe the full methodology of DMD-PS and demonstrate - using the calibration-based concept - an improvement in dynamic range by a factor of ~100 over conventional imaging spectroscopy. The dynamic range of the presented approach will directly benefit from future technological development of DMDs and camera sensors.

  20. 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…