Sample records for image derived input

  1. Image-Derived Input Function for Human Brain Using High Resolution PET Imaging with [11

    E-print Network

    Shen, Jun

    Image-Derived Input Function for Human Brain Using High Resolution PET Imaging with [11 C was to test seven previously published image-input methods in state-of-the-art high resolution PET brain images. Images were obtained with a High Resolution Research Tomograph plus a resolution

  2. A Multimodal Approach to Image-Derived Input Functions for Brain PET

    PubMed Central

    Fung, Edward K.; Planeta-Wilson, Beata; Mulnix, Tim; Carson, Richard E.

    2010-01-01

    Many methods have been proposed for generating an image-derived input function (IDIF) exclusively from PET images. The purpose of this study was to assess the viability of a multimodality approach utilizing registered MR images. 3T-MR and HRRT-PET data were acquired from human subjects. Segmentation of both the left and right carotid arteries was performed in MR images using a 3D level sets method. Vessel centerlines were extracted by parameterization of the segmented voxel coordinates with either a single polynomial curve or a B-spline curve fitted to the segmented data. These centerlines were subsequently re-registered to static PET data to maximize the accurate classification of PET voxels in the ROI. The accuracy of this approach was assessed by comparison of the area under the curve (AUC) of the IDIF to that measured from conventional automated arterial blood sampling. Our method produces curves similar in shape to that of blood sampling. The mean AUC ratio of the centerline region was 0.40±0.19 before re-registration and 0.69±0.26 after re-registration. Increasing the diameter of the carotid ROI produced a smooth reduction in AUC. Thus, even with the high resolution of the HRRT, partial volume correction is still necessary. This study suggests that the combination of PET information with MR segmented regions will demonstrate an improvement over regions based solely on MR or PET alone. PMID:20607124

  3. Noninvasive image derived heart input function for CMRglc measurements in small animal slow infusion FDG PET studies.

    PubMed

    Xiong, Guoming; Paul, Cumming; Todica, Andrei; Hacker, Marcus; Bartenstein, Peter; Böning, Guido

    2012-12-01

    Absolute quantitation of the cerebral metabolic rate for glucose (CMRglc) can be obtained in positron emission tomography (PET) studies when serial measurements of the arterial [(18)F]-fluoro-deoxyglucose (FDG) input are available. Since this is not always practical in PET studies of rodents, there has been considerable interest in defining an image-derived input function (IDIF) by placing a volume of interest (VOI) within the left ventricle of the heart. However, spill-in arising from trapping of FDG in the myocardium often leads to progressive contamination of the IDIF, which propagates to underestimation of the magnitude of CMRglc. We therefore developed a novel, non-invasive method for correcting the IDIF without scaling to a blood sample. To this end, we first obtained serial arterial samples and dynamic FDG-PET data of the head and heart in a group of eight anaesthetized rats. We fitted a bi-exponential function to the serial measurements of the IDIF, and then used the linear graphical Gjedde-Patlak method to describe the accumulation in myocardium. We next estimated the magnitude of myocardial spill-in reaching the left ventricle VOI by assuming a Gaussian point-spread function, and corrected the measured IDIF for this estimated spill-in. Finally, we calculated parametric maps of CMRglc using the corrected IDIF, and for the sake of comparison, relative to serial blood sampling from the femoral artery. The uncorrected IDIF resulted in 20% underestimation of the magnitude of CMRglc relative to the gold standard arterial input method. However, there was no bias with the corrected IDIF, which was robust to the variable extent of myocardial tracer uptake, such that there was a very high correlation between individual CMRglc measurements using the corrected IDIF with gold-standard arterial input results. Based on simulation, we furthermore find that electrocardiogram-gating, i.e. ECG-gating is not necessary for IDIF quantitation using our approach. PMID:23160517

  4. Guiding an image acquisition strategy: MODIS-derived growing season timing and cloud cover probability as inputs to a global agriculture monitoring (GEO-GLAM) system of systems

    NASA Astrophysics Data System (ADS)

    Whitcraft, A. K.; Vermote, E.

    2012-12-01

    Satellite remote sensing is an invaluable tool in the collection of data and generation of information about global agricultural production and food security. In order to secure the necessary image acquisitions for these global agricultural monitoring applications, we must first articulate Earth observation (EO) requirements for the diverse agricultural landscapes and cropping systems which cover the land surface. Crucial to this task are the identification of growing season timing at a meaningful spatial scale, so as to better define the necessary periods of image acquisition, as well as the determination of the likelihood of a cloud-free observation during different portions of the agricultural growing season. To this end, ten years of MODIS imagery have been used to determine phenological transition dates (start, peak, and end of season) and their ranges over that time period at 0.5 degree globally. This is the first set of global, satellite-derived, cropland-specific calendar dates. Because cloud cover presents a temporally and spatially heterogeneous obstacle in optical remote sensing of many important agricultural areas, roughly a decade of MODIS observations have been used to determine the likelihood of a cloud-free observation during different portions of the agricultural growing season at 0.05 degree. This research shows persistent cloud cover during crucial portions of the growing season for some important agricultural regions, information which can be used to better define the actual repeat time required to obtain a valid acquisition and provides evidence for a constellation approach for Earth observations for agricultural monitoring. Coupled with the growing season calendars, this research provides important inputs to agricultural production and food security monitoring in the context of the Global Agricultural Monitoring initiative (GEO-GLAM), an effort by the Group on Earth Observations (GEO) to synergize existing national and regional observation systems for improved agricultural production and food security monitoring.

  5. Car image recognition with lacked input data

    Microsoft Academic Search

    Y. Arai; K. Hirota

    2001-01-01

    A car type recognition system, using methods of the R&FHPR\\/FF (Rough and Fuzzy Hierarchical Pattern Recognition using Fixation Feedback), infer just about correctly based on precise input data. Although, it is difficult, features are extracted completely in general using image processing methods. For systems using fuzzy inference, if input datum is lacking, the system does not work well. A framework

  6. Derived input function from dynamic cardiac 18F-FDG PET images in rodents based on the generalized Gaussian ICA model

    Microsoft Academic Search

    R. Mabrouk; S. Prevost; F. Dubeau; L. Bentabet

    2012-01-01

    The aim of this study is to develop a new method to extract input function (IF) from dynamic positron emission tomography (PET) data using the well known [18F]-2-Deoxy-2-fluoro-d-glucose (18F-FDG) for the determination of the myocardial metabolic rate of glucose (MMRG). In the case of cardiac studies, the IF can be obtained directly from the data by mean of a region

  7. Deriving a Simulation Input Generator and a Coverage Metric

    E-print Network

    Dill, David L.

    Deriving a Simulation Input Generator and a Coverage Metric From a Formal Specification Kanna Shimizu and David L. Dill Stanford University, Stanford, CA Copyright by Kanna Shimizu 2002222 Formal specifications would be optimal Single Chip #12;Copyright by Kanna Shimizu 2002333 Formal vs InformalFormal vs

  8. Hybrid Image- and Blood-Sampling (HIBS) Input Function for Quantification of microPET Data

    PubMed Central

    Shoghi, Kooresh I.; Welch, Michael J.

    2008-01-01

    We describe and validate a hybrid image- and blood-sampling (HIBS) method to derive the input function for quantification of microPET mice data. The HIBS algorithm derives the peak of the input function from the image, which is corrected for recovery, while the tail is derived from 5-6 optimally placed blood sampling points. A Bezier interpolation algorithm is used to link the rightmost image peak data point to the leftmost blood sampling point. To assess the performance of HIBS, 4 mice underwent 60-minute microPET imaging sessions following a 0.40-0.50mCi bolus administration of 18FDG. In total, twenty-one blood samples (bsPTAC) were obtained throughout the imaging session to compare against the proposed HIBS method. MicroPET images were reconstructed using filtered back projection (FBP) with a zoom of 2.75 on the heart. Volumetric regions of interest (VROI) were composed by drawing circular ROIs 3-pixels in diameter on 3-4 transverse planes of the left ventricle. Performance was characterized by kinetic simulations in terms of bias in parameter estimates when bsPTAC and HIBS are used as input functions. The peak of the bsPTAC curve was distorted in comparison to the HIBS-derived curve due to temporal limitations and delay in blood sampling which affected the rates of bidirectional exchange between plasma and tissue. The results highlight limitations in using bsPTAC. The HIBS method, however, yields consistent results and thus is a substitute for bsPTAC. PMID:17998103

  9. Multiple-Input Multiple-Output Radar for Lesion Classification in Ultrawideband Breast Imaging

    Microsoft Academic Search

    Yifan Chen; Ian James Craddock; Panagiotis Kosmas; Mohammad Ghavami; Predrag Rapajic

    2010-01-01

    This paper studies the problem of applying multiple-input multiple-output (MIMO) radar techniques for lesion classification in ultrawideband (UWB) breast imaging. Ongoing work on this topic has suggested that benign and malignant masses, which usually possess remarkable architectural differences, could be distinguished by exploiting their morphology-dependent UWB microwave backscatter. We have previously approached this problem by deriving the complex natural resonances

  10. Deriving Intrinsic Images from Image Sequences

    Microsoft Academic Search

    Yair Weiss

    2001-01-01

    Intrinsic images are a useful midlevel description of scenes proposed by Barrow and Tenenbaum (1). An image is de- composed into two images: a reflectance image and an il- lumination image. Finding such a decomposition remains a difficult problem in computer vision. Here we focus on a slightly easier problem: given a sequence of im- ages where the reflectance is

  11. Approach for Input Uncertainty Propagation and Robust Design in CFD Using Sensitivity Derivatives

    NASA Technical Reports Server (NTRS)

    Putko, Michele M.; Taylor, Arthur C., III; Newman, Perry A.; Green, Lawrence L.

    2002-01-01

    An implementation of the approximate statistical moment method for uncertainty propagation and robust optimization for quasi 3-D Euler CFD code is presented. Given uncertainties in statistically independent, random, normally distributed input variables, first- and second-order statistical moment procedures are performed to approximate the uncertainty in the CFD output. Efficient calculation of both first- and second-order sensitivity derivatives is required. In order to assess the validity of the approximations, these moments are compared with statistical moments generated through Monte Carlo simulations. The uncertainties in the CFD input variables are also incorporated into a robust optimization procedure. For this optimization, statistical moments involving first-order sensitivity derivatives appear in the objective function and system constraints. Second-order sensitivity derivatives are used in a gradient-based search to successfully execute a robust optimization. The approximate methods used throughout the analyses are found to be valid when considering robustness about input parameter mean values.

  12. Digital computer manipulation of high-order linear system equations including systems with input derivatives

    Microsoft Academic Search

    J. H. ANDERSON; G. H. QUALTROUGH

    1970-01-01

    A systematic method for the digital computer manipulation of the equations describing high-order linear processes into canonic state space form is briefly reviewed. The basic method is then extended to embrace system models which, it transpires, include input derivative terms. The paper concludes with a numerical example relating to a boiler dynamic model described by a set of 23 differential

  13. Restoration of images degraded by input scanner vibrations

    Microsoft Academic Search

    George Wolberg; Robert P. Loce

    1995-01-01

    Images scanned in the presence of mechanical vibrations are subject to artifacts such as brightness fluctuation and geometric warping. The goal of this work is to develop an algorithm to invert these distortions and produce an output digital image consistent with a scanner operating under ideal uniform motion conditions. The image restoration algorithm described in this paper applies to typical

  14. Fluorescein Derivatives in Intravital Fluorescence Imaging

    PubMed Central

    Robertson, Thomas A.; Bunel, Florestan; Roberts, Michael S.

    2013-01-01

    Intravital fluorescence microscopy enables the direct imaging of fluorophores in vivo and advanced techniques such as fluorescence lifetime imaging (FLIM) enable the simultaneous detection of multiple fluorophores. Consequently, it is now possible to record distribution and metabolism of a chemical in vivo and to optimise the delivery of fluorophores in vivo. Recent clinical applications with fluorescein and other intravital fluorescent stains have occurred in neurosurgery, dermatology [including photodynamic therapy (PDT)] and endomicroscopy. Potential uses have been identified in periodontal disease, skin graft and cancer surgery. Animal studies have demonstrated that diseased tissue can be specifically stained with fluorophore conjugates. This review focuses on the fluorescein derived fluorophores in common clinical use and provides examples of novel applications from studies in tissue samples. PMID:24709799

  15. MRI-derived arterial input functions for PET kinetic modelling in rats

    NASA Astrophysics Data System (ADS)

    Evans, Eleanor; Sawiak, Stephen J.; Adrian Carpenter, T.

    2013-02-01

    Simultaneous PET-MR acquisition provides the high temporal and spatial resolution of MRI with the specificity of PET. In PET, accurate modelling of physiological function in vivo requires the time-activity curve of tracer in blood plasma, known as the arterial input function (AIF). As the gold standard method of blood sampling is inherently prohibitive in the small animal case, here we discuss how we prepare to rapidly sample MRI signals from gadolinium-doped tracer to obtain the tracer input functions from a simultaneous PET-MR measurement. ?R2* measurements taken from EPI images were used to obtain first pass bolus AIFs in the rat brain from DSC-MRI datasets of 5 rats. AIFs obtained using our automatic algorithm were found to be consistent between animals and compared well with manual methods without need for a priori voxel selection. A variable flip angle FLASH sequence used for T1 mapping was successfully tested in a phantom study, providing accurate measurements of Gd concentration.

  16. Maximum likelihood identification and optimal input design for identifying aircraft stability and control derivatives

    NASA Technical Reports Server (NTRS)

    Stepner, D. E.; Mehra, R. K.

    1973-01-01

    A new method of extracting aircraft stability and control derivatives from flight test data is developed based on the maximum likelihood cirterion. It is shown that this new method is capable of processing data from both linear and nonlinear models, both with and without process noise and includes output error and equation error methods as special cases. The first application of this method to flight test data is reported for lateral maneuvers of the HL-10 and M2/F3 lifting bodies, including the extraction of stability and control derivatives in the presence of wind gusts. All the problems encountered in this identification study are discussed. Several different methods (including a priori weighting, parameter fixing and constrained parameter values) for dealing with identifiability and uniqueness problems are introduced and the results given. The method for the design of optimal inputs for identifying the parameters of linear dynamic systems is also given. The criterion used for the optimization is the sensitivity of the system output to the unknown parameters. Several simple examples are first given and then the results of an extensive stability and control dervative identification simulation for a C-8 aircraft are detailed.

  17. Global Auroral Energy Deposition Derived from Polar UVI Images

    NASA Technical Reports Server (NTRS)

    Fillingim, M. O.; Brittnacher, M. J.; Elsen, R.; Parks, G. K.; Spann, J. F., Jr.; Germany, G. A.

    1997-01-01

    Quantitative measurement of the transfer of energy and momentum to the ionosphere from the solar wind is one of the main objectives of the ISTP program. Global measurement of auroral energy deposition derived from observations of the longer wavelength LBH band emissions made by the Ultraviolet Imager on the Polar spacecraft is one of the key elements in this satellite and ground-based instrument campaign. These "measurements" are inferred by combining information from consecutive images using different filters and have a time resolution on the average of three minutes and are made continuously over a 5 to 8 hour period during each 18 hour orbit of the Polar spacecraft. The energy deposition in the ionosphere from auroral electron precipitation augments are due to Joule heating associated with field aligned currents. Assuming conjugacy of energy deposition between the two hemispheres the total energy input to the ionosphere through electron precipitation can be determined at high time resolution. Previously, precipitating particle measurements along the tracks of low altitude satellites provided only local measurements and the global energy precipitation could be inferred through models but not directly measured. We use the UVI images for the entire month of January 1997 to estimate the global energy deposition at high time resolution. We also sort the energy deposition into sectors to find possible trends, for example, on the dayside and nightside, or the dawn and dusk sides.

  18. Derivative encoding for parallel magnetic resonance imaging a

    PubMed Central

    Shen, Jun

    2011-01-01

    Purpose: To introduce a linear shift-invariant relationship between the partial derivatives of k space signals acquired using multichannel receive coils and to demonstrate that k space derivatives can be used for image unwrapping.Methods: Fourier transform of k space derivatives contains information on the spatial origins of aliased pixels; therefore, images can be reconstructed by k space derivatives. Fully sampled phantom and brain images acquired at 3 T using a standard eight channel receive coil were used to validate the k space derivatives theorem by unwrapping aliased images.Results: Derivative encoding leads to new methods for parallel imaging reconstruction in both k space and image domains. Noise amplification in sensitivity encoding image reconstruction, which is considered to produce the optimal SNR, can be further reduced using k space derivative encoding without making any assumptions on the characteristics of the images to be reconstructed.Conclusions: This work demonstrated that the partial derivative of the k space signal acquired from one coil with respect to one direction can be expressed as a sum of partial derivatives of signals from multiple coils with respect to the perpendicular k space direction(s). This relationship between the partial derivatives of k space signals is linear and shift-invariant in the Cartesian coordinate system. PMID:21992376

  19. Java Library for Input and Output of Image Data and Metadata

    NASA Technical Reports Server (NTRS)

    Deen, Robert; Levoe, Steven

    2003-01-01

    A Java-language library supports input and output (I/O) of image data and metadata (label data) in the format of the Video Image Communication and Retrieval (VICAR) image-processing software and in several similar formats, including a subset of the Planetary Data System (PDS) image file format. The library does the following: It provides low-level, direct access layer, enabling an application subprogram to read and write specific image files, lines, or pixels, and manipulate metadata directly. Two coding/decoding subprograms ("codecs" for short) based on the Java Advanced Imaging (JAI) software provide access to VICAR and PDS images in a file-format-independent manner. The VICAR and PDS codecs enable any program that conforms to the specification of the JAI codec to use VICAR or PDS images automatically, without specific knowledge of the VICAR or PDS format. The library also includes Image I/O plugin subprograms for VICAR and PDS formats. Application programs that conform to the Image I/O specification of Java version 1.4 can utilize any image format for which such a plug-in subprogram exists, without specific knowledge of the format itself. Like the aforementioned codecs, the VICAR and PDS Image I/O plug-in subprograms support reading and writing of metadata.

  20. Deriving intrinsic images from image sequences Computer Science Division

    E-print Network

    Weiss, Yair

    , novel algorithm for re­ covering reflectance images. We illustrate the algorithm's performance on real. The observed image is a product of two images: an illumination image and a reflectance image. We call in order to avoid being fooled by illumination changes. On the intrinsic, reflectance image, on the other

  1. Nonlinear filter derived from topological image features

    SciTech Connect

    Jatko, W.B.; Hunt, M.A.; Tobin, K.W.

    1990-01-01

    A digital machine-inspection system is being developed at Oak Ridge National Laboratory for detecting flaws on printed graphic images. The inspection is based on subtraction of a digitized test image from a reference image to determine the location, number, extent, and contrast of potential flaws. When performing subtractive analysis on the digitized information, two sources of errors in the amplitude of the difference image can develop: (1) spatial misregistration of the reference and test sample or, (2) random fluctuations in the printing process. Variations in printing and registration between samples will generate topological artifacts related to surface structure, which is referred to as edge noise in the difference image. Most feature extraction routines require that the difference image be relatively free of noise to perform properly. A novel algorithm has been developed to filter edge noise from the difference images. The algorithm relies on the a priori assumption that edge noise will be located near locations having a strong intensity gradient in the reference image. The filter is based on the structure of the reference image and is used to attenuate edge features in the difference image. The filtering algorithm, consisting of a geometric transformation, image multiplication, and erosion/dilation, has reduced edge noise by 67% over the unfiltered image and can be implemented using off-the-shelf hardware. 4 refs., 6 figs.

  2. Deriving intrinsic images from image sequences Computer Science Division

    E-print Network

    Kazhdan, Michael

    , novel algorithm for re- covering reflectance images. We illustrate the algorithm's performance on real is a product of two images: an illumination image and a reflectance image. We call this a midlevel description fooled by illumination changes. On the intrinsic, reflectance image, on the other hand, even prim- itive

  3. Boolean Derivatives With Application to Edge Detection for Imaging Systems

    Microsoft Academic Search

    Sos S. Agaian; Karen A. Panetta; Shahan C. Nercessian; Ethan E. Danahy

    2010-01-01

    This paper introduces a new concept of Boolean derivatives as a fusion of partial derivatives of Boolean functions (PDBFs). Three efficient algorithms for the calculation of PDBFs are presented. It is shown that Boolean function derivatives are useful for the application of identifying the location of edge pixels in binary images. The same concept is extended to the development of

  4. Historical changes in terrestrially derived organic carbon inputs to Louisiana continental margin sediments over the past 150 years

    Microsoft Academic Search

    Troy P. Sampere; Thomas S. Bianchi; Mead A. Allison

    2011-01-01

    Major rivers (and associated deltaic environments) provide the dominant pathway for the input of terrestrial-derived organic carbon in sediments (TOCT) to the ocean. Natural watershed processes and land-use changes are important in dictating the amount and character of carbon being buried on continental margins. Seven core sites were occupied on the Louisiana continental margin aboard the R\\/V Pelican in July

  5. Reducing input data via image categorization to improve the speed of copyright content management systems

    NASA Astrophysics Data System (ADS)

    Ikeda, Kanami; Watanabe, Eriko

    2015-02-01

    An optical correlator has the advantage of high data transfer speed and parallel operation. However, in copyright content management systems (CCMSs), the numerous video files that need to be downloaded from the Internet and input to the optical correlator constitute a bottleneck. This paper proposes an image categorization method for CCMSs that uses the difference in the color features between animation and live-action images to remove this bottleneck and increase the speed of CCMSs. The results of experiments conducted indicate that the proposed method achieves a live-action video true rejection rate of 86.7 % and an animation video false rejection rate of 13.3 %. This indicates that the proposed method can improve the overall speed of a CCMS more than twice the original speed.

  6. Landsat Thematic Mapper image-derived MTF

    NASA Technical Reports Server (NTRS)

    Schowengerdt, R. A.; Archwamety, C.; Wrigley, R. C.

    1985-01-01

    The Landsat Image Data Quality Analysis (LIDQA) Program conducted by NASA has the objective to quantify the performance of the Thematic Mapper (TM) on the Landsat-4 and Landsat-5 spacecraft. The interest in the spatial resolution performance of the TM is partly related to the decrease of the instantaneous field of view (IFOV) from 80 m for the MSS to 30 m for the TM. Studies related to the preflight line spread function (LSF), square wave response (SWR), and theoretical component modeling of the TM system modulation transfer function (MTF) have been conducted. However, the need remains to estimate the MTF of the complete system. The present paper is concerned with investigations related to this task. Attention is given to three approaches for measuring the MTF of the TM system from imagery.

  7. Multi-modal pharmacokinetic modelling for DCE-MRI: using diffusion weighted imaging to constrain the local arterial input function

    NASA Astrophysics Data System (ADS)

    Hamy, Valentin; Modat, Marc; Shipley, Rebecca; Dikaios, Nikos; Cleary, Jon; Punwani, Shonit; Ourselin, Sebastien; Atkinson, David; Melbourne, Andrew

    2014-03-01

    The routine acquisition of multi-modal magnetic resonance imaging data in oncology yields the possibility of combined model fitting of traditionally separate models of tissue structure and function. In this work we hypothesise that diffusion weighted imaging data may help constrain the fitting of pharmacokinetic models to dynamic contrast enhanced (DCE) MRI data. Parameters related to tissue perfusion in the intra-voxel incoherent motion (IVIM) modelling of diffusion weighted MRI provide local information on how tissue is likely to perfuse that can be utilised to guide DCE modelling via local modification of the arterial input function (AIF). In this study we investigate, based on multi-parametric head and neck MRI of 8 subjects (4 with head and neck tumours), the benefit of incorporating parameters derived from the IVIM model within the DCE modelling procedure. Although we find the benefit of this procedure to be marginal on the data used in this work, it is conceivable that a technique of this type will be of greater use in a different application.

  8. MULTI-IMAGE SHAPE-FROM-SHADING: DERIVATION OF PLANETARY DIGITAL TERRAIN MODELS USING CLEMENTINE IMAGES

    Microsoft Academic Search

    Volker Lohse; Christian Heipke

    In many cases, the derivation of high-resolution digital terrain models (DTMs) from planetary surfaces using only conventional digital image matching is a problem. The matching methods need at least a stereo pair of images covering an area with sufficient texture. Often though, space missions provide only a few stereo images and planetary surfaces often possess insufficient texture. This paper describes

  9. Early Time Points Perfusion Imaging: Relative Time of Arrival, Maximum Derivatives and Fractional Derivatives

    PubMed Central

    Kwong, Kenneth K.; Wu, Ona; Chan, Suk-Tak; Nelissen, Koen; Kholodov, Mykhaylo; Chesler, David A.

    2011-01-01

    Time of arrival (TOA) of a bolus of contrast agent to the tissue voxel is a reference time point critical for the Early Time Points Perfusion Imaging Method (ET) to make relative cerebral blood flow (rCBF) maps. Due to the low contrast to noise (CNR) condition at TOA, other useful reference time points known as relative time of arrival data points (rTOA) are investigated. Candidate rTOA's include the time to reach the maximum derivative, the maximum second derivative, and the maximum fractional derivative. Each rTOA retains the same relative time distance from TOA for all tissue flow levels provided that ET's basic assumption is met, namely, no contrast agent has a chance to leave the tissue before the time of rTOA. The ET's framework insures that rCBF estimates by different orders of the derivative are theoretically equivalent to each other and monkey perfusion imaging results supported the theory. In rCBF estimation, maximum values of higher order fractional derivatives may be used to replace the maximum derivative which runs a higher risk of violating ET's assumption. Using the maximum values of the derivative of orders ranging from 1 to 1.5 to 2, estimated rCBF results were found to demonstrate a gray-white matter ratio of approximately 3, a number consistent with flow ratio reported in the literature. PMID:21600995

  10. Derivate

    NSDL National Science Digital Library

    2011-03-16

    In this activity, students input functions in order to calculate the derivative and tangent line of that function. This activity allows students to explore tangent lines of various functions. This activity includes supplemental materials, including background information about the topics covered, a description of how to use the application, and exploration questions for use with the java applet.

  11. Antibody-Derived In Vivo Imaging of Tau Pathology

    PubMed Central

    Krishnaswamy, Senthilkumar; Lin, Yan; Rajamohamedsait, Wajitha J.; Rajamohamedsait, Hameetha B.; Krishnamurthy, Pavan

    2014-01-01

    Antibodies or their derivatives as imaging probes for pathological tau protein have great potential, but have not been well studied. In particular, smaller, single-chain-variable antibody fragments (scFv's) are attractive for detecting tau lesions in live subjects. Here, we generated libraries of scFv's and identified numerous phospho-tau-selective scFv's. Peripheral injection of one of these scFv's consistently resulted in a strong in vivo brain signal in transgenic tauopathy mice, but not in wild-type or amyloid-? plaque mice. The parent tau antibody provided similar results, albeit with a weaker signal intensity. The imaging signal correlated very well with colocalization of the probe with intraneuronal tau aggregates. Both were associated with markers of endosomes, autophagosomes, and lysosomes, suggesting their interaction in these degradation pathways. Such specific antibody-derived imaging probes have great potential as diagnostic markers for Alzheimer's disease and related tauopathies. PMID:25505335

  12. A text input system developed by using lips image recognition based LabVIEW for the seriously disabled.

    PubMed

    Chen, S C; Shao, C L; Liang, C K; Lin, S W; Huang, T H; Hsieh, M C; Yang, C H; Luo, C H; Wuo, C M

    2004-01-01

    In this paper, we present a text input system for the seriously disabled by using lips image recognition based on LabVIEW. This system can be divided into the software subsystem and the hardware subsystem. In the software subsystem, we adopted the technique of image processing to recognize the status of mouth-opened or mouth-closed depending the relative distance between the upper lip and the lower lip. In the hardware subsystem, parallel port built in PC is used to transmit the recognized result of mouth status to the Morse-code text input system. Integrating the software subsystem with the hardware subsystem, we implement a text input system by using lips image recognition programmed in LabVIEW language. We hope the system can help the seriously disabled to communicate with normal people more easily. PMID:17271421

  13. Effect of Scaling Transfer Between Evapotranpiration Maps Derived from LANDSAT7 and Modis Images

    NASA Astrophysics Data System (ADS)

    Hong, S.; Hendrickx, J. M.; Borchers, B.

    2004-12-01

    Remotely sensed images of the Earth's surface provide information about the spatial distribution of evapotranspiration. Since, the spatial resolution of evapotranspiration predictions depends on the sensor type; scaling transfer between images of different scales needs to be investigated. In this study, the Surface Energy Balance Algorithm for Land (SEBAL) was used to derive evapotranspiration maps from Landsat7 Thematic Mapper (TM) and Moderate Resolution Imaging Spectroradiometer (MODIS) images. LandSat7 has a spatial resolution of 60 m, MODIS of 1000 m. Two up-scaling procedures are evaluated. The first consists of averaging 60 by 60 m LandSat pixels of spectral radiances or of intermediate SEBAL input surface parameters (albedo, NDVI, surface temperature) to obtain 1000 by 1000 m pixels at the MODIS scale before SEBAL is applied. The second consists of first applying SEBAL and then to average from 60 m to 1000 m spatial resolution. The averaging process (aggregation) will include calculating arithmetic and geometric means. In the downscaling process (MODIS to LandSat), an earlier LandSat image will be used to characterize the fine scale variability within the large MODIS pixels. Two down-scaling procedures are evaluated. The first consists of downscaling the original MODIS spectral data; the second of downscaling the evapotranspiration maps at MODIS scale. The objective of this study is to investigate the effect of the scaling transfer processes on the spatial distribution of evapotranspiration in arid riparian areas.

  14. Priming in permafrost soils: High vulnerability of arctic soil organic carbon to increased input of plant-derived compounds

    NASA Astrophysics Data System (ADS)

    Wild, Birgit; Gentsch, Norman; Capek, Petr; Diakova, Katerina; Alves, Ricardo; Barta, Jiri; Gittel, Antje; Guggenberger, Georg; Lashchinskiy, Nikolay; Knoltsch, Anna; Mikutta, Robert; Santruckova, Hana; Schnecker, Jörg; Shibistova, Olga; Takriti, Mounir; Urich, Tim; Watzka, Margarete; Richter, Andreas

    2015-04-01

    Arctic ecosystems are warming rapidly, resulting in a stimulation of both plant primary production and soil organic matter (SOM) decomposition. In addition to this direct stimulation, SOM decomposition might also be indirectly affected by rising temperatures mediated by the increase in plant productivity. Higher root litter production for instance might decrease SOM decomposition by providing soil microorganisms with alternative C and N sources ("negative priming"), or might increase SOM decomposition by facilitating microbial growth and enzyme production ("positive priming"). With about 1,700 Pg of organic C stored in arctic soils, and 88% of that in horizons deeper than 30 cm, it is crucial to understand the controls on SOM decomposition in different horizons of arctic permafrost soils, and thus the vulnerability of SOM to changes in C and N availability in a future climate. We here report on the vulnerability of SOM in arctic permafrost soils to an increased input of plant-derived organic compounds, and on its variability across soil horizons and sites. We simulated an increased input of plant-derived compounds by amending soil samples with 13C-labelled cellulose or protein, and compared the mineralization of native, unlabelled soil organic C (SOC) to unamended control samples. Our experiment included 119 individual samples of arctic permafrost soils, covering four sites across the Siberian Arctic, and five soil horizons, i.e., organic topsoil, mineral topsoil, mineral subsoil and cryoturbated material (topsoil material buried in the subsoil by freeze-thaw processes) from the active layer, as well as thawed material from the upper permafrost. Our findings suggest that changes in C and N availability in Arctic soils, such as mediated by plants, have a high potential to alter the decomposition of SOM, but also point at fundamental differences between soil horizons. In the organic topsoil, SOC mineralization increased by 51% after addition of protein, but was not affected by cellulose, suggesting predominant N limitation of the microbial decomposer community, and a high vulnerability of SOM to increases in N availability. In contrast, in mineral subsoil and thawed permafrost, SOC mineralization was stimulated by both cellulose and protein (between 23 and 120%), cellulose- and protein-derived C was efficiently incorporated into the microbial biomass, and effects of both cellulose and protein were significantly correlated. These findings suggest predominant C limitation of the microbial decomposer community in deeper, mineral horizons of arctic permafrost soils, and point at a high vulnerability of SOM to increased C availability, e.g., due to higher root litter production. We estimate that on a circum-arctic scale, increases in C and N availability have the potential to stimulate SOC mineralization in the order of several Tg C per day. Together with the direct stimulation of SOC mineralization by rising temperatures, this indirect stimulation can counteract the increased CO2 fixation by plants, and thus reduce the C sink strength of arctic ecosystems or even provoke net ecosystem C losses that might induce a positive feedback to global warming.

  15. Spectroscopic analysis and in vitro imaging applications of a pH responsive AIE sensor with a two-input inhibit function.

    PubMed

    Zhou, Zhan; Gu, Fenglong; Peng, Liang; Hu, Ying; Wang, Qianming

    2015-07-14

    A novel terpyridine derivative formed stable aggregates in aqueous media (DMSO/H2O = 1/99) with dramatically enhanced fluorescence compared to its organic solution. Moreover, the ultra-violet absorption spectra also demonstrated specific responses to the incorporation of water. The yellow emission at 557 nm changed to a solution with intense greenish luminescence only in the presence of protons and it conformed to a molecular logic gate with a two-input INHIBIT function. This molecular-based material could permeate into live cells and remain undissociated in the cytoplasm. The new aggregation induced emission (AIE) pH type bio-probe permitted easy collection of yellow luminescence images on a fluorescent microscope. As designed, it displayed striking green emission in organelles at low internal pH. This feature enabled the self-assembled structure to have a whole new function for the pH detection within the field of cell imaging. PMID:26121058

  16. Direct Characterization of Arterial Input Functions by Fluorescence Imaging of Exposed Carotid Artery to Facilitate Kinetic Analysis

    PubMed Central

    Elliott, Jonathan T.; Tichauer, Kenneth M.; Samkoe, Kimberley S.; Gunn, Jason R.; Sexton, Kristian J.; Pogue, Brian W.

    2014-01-01

    Purpose With the goal of facilitating tracer kinetic analysis in small-animal planar fluorescence imaging, an experimental method for characterizing tracer arterial input functions is presented. The proposed method involves exposing the common carotid arteries by surgical dissection, which can then be imaged directly during tracer injection and clearance. Procedures Arterial concentration curves of IRDye-700DX-carboxylate, IRDye-800CW-EGF, and IRDye-800CW conjugated to anti-EGFR Affibody are recovered from athymic female mice (n=12) by directly imaging exposed vessels. Images were acquired with two imaging protocols: a slow-kinetics approach (temporal resolution=45 s) to recover the arterial curves from two tracers simultaneously, and a fast-kinetics approach (temporal resolution=500 ms) to characterize the first-pass peak of a single tracer. Arterial input functions obtained by the carotid imaging technique, as well as plasma curves measured by blood sampling were fit with a biexponential pharmacokinetic model. Results Pharmacological fast- and slow-phase rate constants recovered with the proposed method were 0.37±0.26 and 0.007±0.001 min?1, respectively, for the IRDye700DX-C. For the IRDye800CW-EGF, the rate constants were 0.11±0.13 and 0.003±0.002 min?1. These rate constants did not differ significantly from those calculated previously by blood sampling, as determined by an F test; however, the between-subject variability was four times lower for arterial curves recovered using the proposed technique, compared with blood sampling. Conclusions The proposed technique enables the direct characterization of arterial input functions for kinetic analysis. As this method requires no additional instrumentation, it is immediately deployable in commercially available planar fluorescence imaging systems. PMID:24420443

  17. One goal of examing satellite images is to derive maps of earth Digital Image Classification Has Two Components

    E-print Network

    Frank, Thomas D.

    One goal of examing satellite images is to derive maps of earth #12;Digital Image Classification Image Classification The objective of digital image classification is to partition feature space into decision regions, then to assign pixels in an image to the most likely feature category. #12;By selecting

  18. Early Time Points Perfusion Imaging: Theoretical Analysis of Correction Factors for relative cerebral blood flow Estimation Given Local Arterial Input Function

    PubMed Central

    Kwong, Kenneth K.; Chesler, David A.

    2011-01-01

    If local arterial input function (AIF) could be identified, we present a theoretical approach to generate a correction factor based on local AIF for the estimation of relative cerebral blood flow (rCBF) under the framework of early time points perfusion imaging (ET). If C(t), the contrast agent bolus concentration signal time course, is used for rCBF estimation in ET, the correction factor for C(t) is the integral of its local AIF. The recipe to apply the correction factor is to divide C(t) by the integral of its local AIF to obtain the correct rCBF. By similar analysis, the correction factor for the maximum derivative (MD1) of C(t) is the maximum signal of AIF and the correction factor for the maximum second derivative (MD2) of C(t) is the maximum derivative of AIF. In the specific case of using normalized gamma-variate function as a model for AIF, the correction factor for C(t) (but not for MD1) at the time to reach the maximum derivative is relatively insensitive to the shape of the local AIF. PMID:21497658

  19. The least-squares mixing models to generate fraction images derived from remote sensing multispectral data

    Microsoft Academic Search

    Yosio Edemir Shimabukuro; James A. Smith

    1991-01-01

    Constrained-least-squares (CLS) and weighted-least-squares (WLS) mixing models for generating fraction images derived from remote sensing multispectral data are presented. An experiment considering three components within the pixels-eucalyptus, soil (understory), and shade-was performed. The generated fraction images for shade (shade image) derived from these two methods were compared by considering the performance and computer time. The derived shade images are related

  20. A neural network for unsupervised categorization of multivalued input patterns: an application to satellite image clustering

    Microsoft Academic Search

    Andrea Baraldi; Flavio Parmiggiani

    1995-01-01

    Presents an implementation of an artificial neural network (ANN) which performs unsupervised detection of recognition categories from arbitrary sequences of multivalued input patterns. The proposed ANN is called Simplified Adaptive Resonance Theory Neural Network (SARTNN). First, an Improved Adaptive Resonance Theory 1 (IART1)-based neural network for binary pattern analysis is discussed and a Simplified ART1 (SART1) model is proposed. Second,

  1. Multi-eye input experiments for UAV image navigation and control

    NASA Astrophysics Data System (ADS)

    Baer, Wolfgang

    2010-04-01

    Real time Unmanned Arial Vehicle (UAV) image registration is achieved by stimulating one eye with a live video image from a flying UAV while stimulating the other eye with calculated images. The calculated image is initialized by telemetry signals from the UAV and corrected using the Perspective View Nascent Technology (PVNT) software package model-image feedback algorithm. Live and registered calculated images are superimposed allowing command functions including target geo-location, UAV sensor slewing, tracking, and way point flight control. When the same equipment is used with the naked eye the forward observer function can be implemented to produce accurate target coordinates. The paper will then discuss UAV mission control and forward observer target tracking experiments conducted at Camp Roberts, California.

  2. Effect of Scaling Transfer between Evapotranspiration Maps Derived from LandSat 7 and MODIS Images

    E-print Network

    Borchers, Brian

    Effect of Scaling Transfer between Evapotranspiration Maps Derived from LandSat 7 and MODIS Images derived from LandSat 7 and MODIS images. The results of this study demonstrate: (1) good agreement of SEBAL evapotranspiration estimates between LandSat 7 and MODIS images; (2) up- and down

  3. Input modeling: input modeling

    Microsoft Academic Search

    Lawrence Leemis

    2003-01-01

    Most discrete-event simulation models have stochastic elements that mimic the probabilistic nature of the system under consideration. A close match between the input model and the true underlying probabilistic mechanism associated with the system is required for successful input modeling. The general question considered here is how to model an element (e.g., arrival process, service times) in a discrete-event simulation

  4. Single input state, single-mode fiber-based polarization-sensitive optical frequency domain imaging by eigenpolarization referencing.

    PubMed

    Lippok, Norman; Villiger, Martin; Jun, Changsu; Bouma, Brett E

    2015-05-01

    Fiber-based polarization-sensitive optical frequency domain imaging is more challenging than free-space implementations. Using multiple input states, fiber-based systems provide sample birefringence information with the benefit of a flexible sample arm but come at the cost of increased system and acquisition complexity, and either reduce acquisition speed or require increased acquisition bandwidth. Here we show that with the calibration of a single polarization state, fiber-based configurations can approach the conceptual simplicity of traditional free-space configurations. We remotely control the polarization state of the light incident at the sample using the eigenpolarization states of a wave plate as a reference, and determine the Jones matrix of the output fiber. We demonstrate this method for polarization-sensitive imaging of biological samples. PMID:25927775

  5. Digital Image Processing "Cookbook": A method to derive bathymetric data from high spatial resolution multi-

    E-print Network

    Wright, Dawn Jeannine

    Digital Image Processing "Cookbook": A method to derive bathymetric data from high spatial imagery. It records image processing steps of the second run through an image specific methodology;Processing Method: Overview 1) Viewing of Images Software: ENVI, ArcGIS 2) Data Conversion from DN (digital

  6. Importance of budgets for estimating the input of groundwater-derived nutrients to an eutrophic tidal river and estuary

    NASA Astrophysics Data System (ADS)

    Makings, Uriah; Santos, Isaac R.; Maher, Damien T.; Golsby-Smith, Lindsay; Eyre, Bradley D.

    2014-04-01

    Groundwater is often overlooked as a source of nutrients to estuaries and most previous groundwater-surface water exchange studies did not consider the input of dissolved organic nutrients. Here, we hypothesize that groundwater is contributing to high dissolved inorganic and organic nutrient concentrations in an eutrophic subtropical tidal river and estuary (Caboolture River, Queensland, Australia). Several spatial radon (222Rn, a natural groundwater tracer) surveys indicated that the majority of groundwater discharge occurred in the tidal river just upstream of the estuary, and that the radon hotspot did not necessarily coincide with the nutrient hotspot. A radon mass balance revealed that groundwater discharge into the tidal river was equivalent to about 50% of the gauged river flow in February 2012. Groundwater discharge apparently contributed 85% of ammonium and 35% of phosphate entering the estuary. In spite of significant correlations between radon and nitrate and dissolved organic nitrogen (DON) during spatial surveys, groundwater could account for only 7% of nitrate and 9% of DON inputs due to low groundwater concentrations and other sources (i.e., apparently a sewage treatment plant for nitrate and floodplain tributaries for DON). Because total dissolved nitrogen (TDN) was dominated by DON (69%) and nitrate (23%), the groundwater ammonium inputs were a minor source to the TDN pool within the tidal river and estuary. This study demonstrated that correlations between a groundwater tracer and nutrient concentrations do not necessarily illustrate causation. To assess how groundwater drives nutrient dynamics in estuaries, it may be important to include the tidal river (not only the estuarine salinity gradient) in field investigations, consider DON (not only ammonium and nitrate), and perform detailed budgets that include minor tributaries.

  7. High resolution fire danger modeling : integration of quantitative precipitation amount estimates derived from weather radars as an input of FWI

    NASA Astrophysics Data System (ADS)

    Cloppet, E.; Regimbeau, M.

    2009-09-01

    Fire meteo indices provide efficient guidance tools for the prevention, early warning and surveillance of forest fires. The indices are based on meteorological input data. The underlying approach is to exploit meteorological information as fully as possible to model the soil water content, biomass condition and fire danger. Fire meteorological danger is estimated by Météo-France at national level through the use of Fire Weather Index. The fire index services developed within the PREVIEW project (2005-2008) offer for the first time very high resolution mapping of forest fire risk. The high resolution FWI has been implemented in France complementary to the existing EFFIS operated by the Joint Research Center. A new method (ANTILOPE method) of combining precipitation data originating from different sources like rain gauges and weather radar measurements has been applied in the new service. Some of the advantages of this new service are: · Improved detection of local features of fire risk · More accurate analysis of meteorological input data used in forest fire index models providing added value for forest fire risk forecasts · Use of radar precipitation data "as is” utilizing the higher resolution, i.e. avoiding averaging operations The improved accuracy and spatial resolution of the indices provide a powerful early warning tool for national and regional civil protection and fire fighting authorities to alert and initiate forest fire fighting actions and measures.

  8. Design criteria for a multiple input land use system. [digital image processing techniques

    NASA Technical Reports Server (NTRS)

    Billingsley, F. C.; Bryant, N. A.

    1975-01-01

    A design is presented that proposes the use of digital image processing techniques to interface existing geocoded data sets and information management systems with thematic maps and remote sensed imagery. The basic premise is that geocoded data sets can be referenced to a raster scan that is equivalent to a grid cell data set, and that images taken of thematic maps or from remote sensing platforms can be converted to a raster scan. A major advantage of the raster format is that x, y coordinates are implicitly recognized by their position in the scan, and z values can be treated as Boolean layers in a three-dimensional data space. Such a system permits the rapid incorporation of data sets, rapid comparison of data sets, and adaptation to variable scales by resampling the raster scans.

  9. Short-Range Ultra-Wideband Imaging with Multiple-Input Multiple-Output Arrays

    Microsoft Academic Search

    X. Zhuge

    2010-01-01

    Compact, cost-efficient and high-resolution imaging sensors are especially desirable in the field of short-range observation and surveillance. Such sensors are of great value in fields of security, rescue and medical applications. Systems can be formed for various practical purposes, such as detecting concealed weapons in public places, locating people inside buildings or beneath rubbles during emergency rescue, detecting landmine with

  10. Functional Imaging of the Human Brainstem during Somatosensory Input and Autonomic Output

    PubMed Central

    Henderson, Luke A.; Macefield, Vaughan G.

    2013-01-01

    Over the past half a century, many investigations in experimental animal have explored the functional roles of specific regions in the brainstem. Despite the accumulation of a considerable body of knowledge in, primarily, anesthetized preparations, relatively few studies have explored brainstem function in awake humans. It is important that human brainstem function is explored given that many neurological conditions, from obstructive sleep apnea, chronic pain, and hypertension, likely involve significant changes in the processing of information within the brainstem. Recent advances in the collection and processing of magnetic resonance images have resulted in the possibility of exploring brainstem activity changes in awake healthy individuals and in those with various clinical conditions. We and others have begun to explore changes in brainstem activity in humans during a number of challenges, including cutaneous and muscle pain, as well as during maneuvers that evoke increases in sympathetic nerve activity. More recently we have successfully recorded sympathetic nerve activity concurrently with functional magnetic resonance imaging of the brainstem, which will allow us, for the first time to explore brainstem sites directly responsible for conditions such as hypertension. Since many pathophysiological conditions no doubt involve changes in brainstem function and structure, defining these changes will likely result in a greater ability to develop more effective treatment regimens. PMID:24062670

  11. Cortical long-range interactions embed statistical knowledge of natural sensory input: a voltage-sensitive dye imaging study

    PubMed Central

    Onat, Selim; Jancke, Dirk; König, Peter

    2013-01-01

    How is contextual processing as demonstrated with simplified stimuli, cortically enacted in response to ecologically relevant complex and dynamic stimuli? Using voltage-sensitive dye imaging, we captured mesoscopic population dynamics across several square millimeters of cat primary visual cortex. By presenting natural movies locally through either one or two adjacent apertures, we show that simultaneous presentation leads to mutual facilitation of activity. These synergistic effects were most effective when both movie patches originated from the same natural movie, thus forming a coherent stimulus in which the inherent spatio-temporal structure of natural movies were preserved in accord with Gestalt principles of perceptual organization. These results suggest that natural sensory input triggers cooperative mechanisms that are imprinted into the cortical functional architecture as early as in primary visual cortex. PMID:24358899

  12. Cortical long-range interactions embed statistical knowledge of natural sensory input: a voltage-sensitive dye imaging study.

    PubMed

    Onat, Selim; Jancke, Dirk; König, Peter

    2013-01-01

    How is contextual processing as demonstrated with simplified stimuli, cortically enacted in response to ecologically relevant complex and dynamic stimuli? Using voltage-sensitive dye imaging, we captured mesoscopic population dynamics across several square millimeters of cat primary visual cortex. By presenting natural movies locally through either one or two adjacent apertures, we show that simultaneous presentation leads to mutual facilitation of activity. These synergistic effects were most effective when both movie patches originated from the same natural movie, thus forming a coherent stimulus in which the inherent spatio-temporal structure of natural movies were preserved in accord with Gestalt principles of perceptual organization. These results suggest that natural sensory input triggers cooperative mechanisms that are imprinted into the cortical functional architecture as early as in primary visual cortex. PMID:24358899

  13. High Performance Derivative-Free Optimization Applied to Biomedical Image Registration

    Microsoft Academic Search

    Mark P. Wachowiak; Terry M. Peters

    2005-01-01

    Optimization of a similarity metric is an essen- tial component in most medical image registration approaches based on image intensities. In this paper, two new, determinis- tic, derivative-free optimization algorithms are parallelized and adapted for image registration. DIRECT (dividing rectangles) is a global technique for linearly bounded problems, and the multidirectional search (MDS) is a local method. Unlike many other

  14. Movetent Analysis Of Digital 3D Images Derived From Serial Section Images

    NASA Astrophysics Data System (ADS)

    Tascini, Guido

    1984-08-01

    With the growth of digital and electronic i maging techniques in medicine particularly useful are the 3-D data for diagnosis and therapy. The representation of 3-D objects adopted uses the 'octree' data structure and is derived from serial section 2-D ima ges, as in CT. The slice-images, pre-proces sed with segmentation techniques and then processed to obtain quadtrees, allow by sim ple technique to reconstruct 3-D represen tation with octrees. For the movement analx sis and generation is adopted a syntax- di rected tree-transducer.The time-varying mages are represented by a sequence of 8-trees and the matching process is performed by parser. Many rules adopted for motion a nalysis and generation are described. Key-words: quadtree, octree, serial-section motion-primitive, tree-translation, parsing.

  15. A Uni ed Framework for Image-Derived Invariants

    E-print Network

    Wang, Yuan-Fang

    such as the short-time Fourier analysis. #12;A word on the notational convention: matrices and vectors Department of Computer Science University of California Santa Barbara, CA 93106 Abstract: We propose, such as wavelets, short-time Fourier transform, and splines. 1 Introduction Image features and shape descriptors

  16. Using Sediment Records to Reconstruct Historical Inputs Combustion-Derived Contaminants to Urban Airsheds/Watersheds: A Case Study From the Puget Sound

    NASA Astrophysics Data System (ADS)

    Louchouarn, P. P.; Kuo, L.; Brandenberger, J.; Marcantonio, F.; Wade, T. L.; Crecelius, E.; Gobeil, C.

    2008-12-01

    Urban centers are major sources of combustion-derived particulate matter (e.g. black carbon (BC), polycyclic aromatic hydrocarbons (PAH), anhydrosugars) and volatile organic compounds to the atmosphere. Evidence is mounting that atmospheric emissions from combustion sources remain major contributors to air pollution of urban systems. For example, recent historical reconstructions of depositional fluxes for pyrogenic PAHs close to urban systems have shown an unanticipated reversal in the trends of decreasing emissions initiated during the mid-20th Century. Here we compare a series of historical reconstructions of combustion emission in urban and rural airsheds over the last century using sedimentary records. A complex suite of combustion proxies (BC, PAHs, anhydrosugars, stable lead concentrations and isotope signatures) assisted in elucidating major changes in the type of atmospheric aerosols originating from specific processes (i.e. biomass burning vs. fossil fuel combustion) or fuel sources (wood vs. coal vs. oil). In all studied locations, coal continues to be a major source of combustion-derived aerosols since the early 20th Century. Recently, however, oil and biomass combustion have become substantial additional sources of atmospheric contamination. In the Puget Sound basin, along the Pacific Northwest region of the U.S., rural locations not impacted by direct point sources of contamination have helped assess the influence of catalytic converters on concentrations of oil-derived PAH and lead inputs since the early 1970s. Although atmospheric deposition of lead has continued to drop since the introduction of catalytic converters and ban on leaded gasoline, PAH inputs have "rebounded" in the last decade. A similar steady and recent rise in PAH accumulations in urban systems has been ascribed to continued urban sprawl and increasing vehicular traffic. In the U.S., automotive emissions, whether from gasoline or diesel combustion, are becoming a major source of combustion-derived PM and BC to the atmosphere and have started to replace coal as the major source in some surficial reservoirs. This increased urban influence of gasoline and diesel combustion on BC emissions was also observed in Europe both from model estimates as well as from measured fluxes in recent lake sediments.

  17. Recent rapid thinning of the ``Mer de Glace'' glacier derived from satellite optical images

    E-print Network

    Berthier, Etienne

    Recent rapid thinning of the ``Mer de Glace'' glacier derived from satellite optical images E. Comparisons with topographic profiles and a differential DEM from aerial photographs obtained on the Mer de. Baratoux, C. Vincent, and F. Re´my (2004), Recent rapid thinning of the ``Mer de Glace'' glacier derived

  18. Benzothiadiazole Derivatives as Fluorescence Imaging Probes: Beyond Classical Scaffolds.

    PubMed

    Neto, Brenno A D; Carvalho, Pedro H P R; Correa, Jose R

    2015-06-16

    This Account describes the origins, features, importance, and trends of the use of fluorescent small-molecule 2,1,3-benzothiadiazole (BTD) derivatives as a new class of bioprobes applied to bioimaging analyses of several (live and fixed) cell types. BTDs have been successfully used as probes for a plethora of biological analyses for only a few years, and the impressive responses obtained by using this important class of heterocycle are fostering the development of new fluorescent BTDs and expanding the biological applications of such derivatives. The first use of a fluorescent small-molecule BTD derivative as a selective cellular probe dates back to 2010, and since then impressive advances have been described by us and others. The well-known limitations of classical scaffolds urged the development of new classes of bioprobes. Although great developments have been achieved by using classical scaffolds such as coumarins, BODIPYs, fluoresceins, rhodamines, cyanines, and phenoxazines, there is still much to be done, and BTDs aim to succeed where these dyes have shown their limitations. Important organelles and cell components such as nuclear DNA, mitochondria, lipid droplets, and others have already been successfully labeled by fluorescent small-molecule BTD derivatives. New technological systems that use BTDs as the fluorophores for bioimaging experiments have been described in recent scientific literature. The successful application of BTDs as selective bioprobes has led some groups to explore their potential for use in studying membrane pores or tumor cells under hypoxic conditions. Finally, BTDs have also been used as fluorescent tags to investigate the action mechanism of some antitumor compounds. The attractive photophysical data typically observed for ?-extended BTD derivatives is fostering interest in the use of this new class of bioprobes. Large Stokes shifts, large molar extinction coefficients, high quantum yields, high stability when stored in solution or as pure solids, no fading even after long periods of irradiation, bright emissions with no blinking, good signal-to-noise ratios, efficiency to transpose the cell membrane, and irradiation preferentially in the visible-light region are just some features noted by using BTDs. As the pioneering group in the use of fluorescent small-molecule BTDs for bioimaging purposes, we feel pleased to share our experience, results, advances, and personal perspectives with the readers of this Account. The readers will clearly note the huge advantages of using fluorescent BTDs over classical scaffolds, and hopefully they will be inspired and motivated to further BTD technology in the fields of molecular and cellular biology. PMID:25978615

  19. No-reference image quality assessment based on log-derivative statistics of natural scenes

    NASA Astrophysics Data System (ADS)

    Zhang, Yi; Chandler, Damon M.

    2013-10-01

    We propose an efficient blind/no-reference image quality assessment algorithm using a log-derivative statistical model of natural scenes. Our method, called DErivative Statistics-based QUality Evaluator (DESIQUE), extracts image quality-related statistical features at two image scales in both the spatial and frequency domains. In the spatial domain, normalized pixel values of an image are modeled in two ways: pointwise-based statistics for single pixel values and pairwise-based log-derivative statistics for the relationship of pixel pairs. In the frequency domain, log-Gabor filters are used to extract the fine scales of the image, which are also modeled by the log-derivative statistics. All of these statistics can be fitted by a generalized Gaussian distribution model, and the estimated parameters are fed into combined frameworks to estimate image quality. We train our models on the LIVE database by using optimized support vector machine learning. Experiment results tested on other databases show that the proposed algorithm not only yields a substantial improvement in predictive performance as compared to other state-of-the-art no-reference image quality assessment methods, but also maintains a high computational efficiency.

  20. Automated Computer-derived Prostate Volumes from MR Imaging Data: Comparison with Radiologist-derived MR Imaging and Pathologic Specimen Volumes

    PubMed Central

    Bulman, Julie C.; Toth, Robert; Patel, Amish D.; Bloch, B. Nicolas; McMahon, Colm J.; Ngo, Long; Madabhushi, Anant

    2012-01-01

    Purpose: To compare prostate gland volume (PV) estimation of automated computer-generated multifeature active shape models (MFAs) performed with 3-T magnetic resonance (MR) imaging with that of other methods of PV assessment, with pathologic specimens as the reference standard. Materials and Methods: All subjects provided written informed consent for this HIPAA-compliant and institutional review board–approved study. Freshly weighed prostatectomy specimens from 91 patients (mean age, 59 years; range, 42–84 years) served as the reference standard. PVs were manually calculated by two independent readers from MR images by using the standard ellipsoid formula. Planimetry PV was calculated from gland areas generated by two independent investigators by using manually drawn regions of interest. Computer-automated assessment of PV with an MFA was determined by the aggregate computer-calculated prostate area over the range of axial T2-weighted prostate MR images. Linear regression, linear mixed-effects models, concordance correlation coefficients, and Bland-Altman limits of agreement were used to compare volume estimation methods. Results: MFA-derived PVs had the best correlation with pathologic specimen PVs (slope, 0.888). Planimetry derived volumes produced slopes of 0.864 and 0.804 for two independent readers when compared with specimen PVs. Ellipsoid formula–derived PVs had slopes closest to one when compared with planimetry PVs. Manual MR imaging and MFA PV estimates had high concordance correlation coefficients with pathologic specimens. Conclusion: MFAs with axial T2-weighted MR imaging provided an automated and efficient tool with which to assess PV. Both MFAs and MR imaging planimetry require adjustments for optimized PV accuracy when compared with prostatectomy specimens. © RSNA, 2012 PMID:22190657

  1. Martian spectral units derived from ISM imaging spectrometer data

    NASA Technical Reports Server (NTRS)

    Murchie, S.; Mustard, J.; Saylor, R.

    1993-01-01

    Based on results of the Viking mission, the soil layer of Mars has been thought to be fairly homogeneous and to consist of a mixture of as few as two components, a 'dark gray' basaltic material and a 'bright red' altered material. However, near-infrared reflectance spectra measured recently both telescopically and from spacecraft indicate compositional heterogeneity beyond what can be explained by just two components. In particular, data from the ISM imaging spectrometer, which observed much of the equatorial region at a spatial resolution of approximately 22 km, indicate spatial differences in the presence and abundance of Fe-containing phases, hydroxylated silicates, and H2O. The ISM data was used to define, characterize, and map soil 'units' based on their spectral properties. The spatial distribution of these 'units' were compared to morphologic, visible color, and thermal inertia features recognized in Viking data.

  2. Imaging and Tracking of Bone Marrow-Derived Immune and Stem Cells

    PubMed Central

    Zhao, Youbo; Bower, Andrew J.; Graf, Benedikt W.; Boppart, Marni D.; Boppart, Stephen A.

    2014-01-01

    Bone marrow (BM)-derived stem and immune cells play critical roles in maintaining the health, regeneration, and repair of many tissues. Given their important functions in tissue regeneration and therapy, tracking the dynamic behaviors of BM-derived cells has been a long-standing research goal of both biologists and engineers. Because of the complex cellular-level processes involved, real-time imaging technologies that have sufficient spatial and temporal resolution to visualize them are needed. In addition, in order to track cellular dynamics, special attention is needed to account for changes in the microenvironment where the cells reside, for example, tissue contraction, stretching, development, etc. In this chapter, we introduce methods for real-time imaging and longitudinal tracking of BM-derived immune and stem cells in in vivo three-dimensional (3-D) tissue environments with an integrated optical microscope. The integrated microscope combines multiple imaging functions derived from optical coherence tomography (OCT) and multiphoton microscopy (MPM), including optical coherence microscopy (OCM), micro-vasculature imaging, two-photon excited fluorescence (TPEF), and second harmonic generation (SHG) microscopy. Short- and long-term tracking of the dynamic behavior of BM-derived cells involved in cutaneous wound healing and skin grafting in green fluorescent protein (GFP) BM-transplanted mice is demonstrated. Methods and algorithms for nonrigid registration of time-lapse images are introduced, which allows for long-term tracking of cell dynamics over several months. PMID:23737096

  3. A downscaling framework for brightness temperature and near surface soil moisture images derived from ESTAR

    NASA Astrophysics Data System (ADS)

    Parada, L. M.; Liang, X.

    2002-12-01

    Brightness temperature images derived from electronically scanned thin array radiometer (ESTAR) may be used for validation of or assimilation into radiation transfer models, and for derivation of near-surface soil moisture images. Near-surface soil moisture may in turn be assimilated into land-surface models to improve their predictive capabilities. Thus, the availability of such images is crucial for a better understanding and characterization of atmosphere-surface dynamics and for improving weather forecasts. It is expected that brightness temperature images taken from space may eventually be available at a resolution of 10-km by 10-km. Various researchers have reported that the derived near surface soil moisture images posses scaling properties over scales ranging from 200-m to 90-km. These findings suggest that it may be possible to statistically characterize the effects of sub-grid variability of soil moisture. This study presents a new downscaling framework for brightness temperature and soil moisture images derived from ESTAR. The simple mathematical model used for this purpose is clearly defined. Validation is performed with the brightness temperature images taken during the Southern Great Plains Hydrology Experiment of 1997 (SGP97). The results obtained show that the proposed downscaling scheme is capable of accurately capturing the first and second order statistics of the observed brightness temperature images. The work presented here constitutes a first attempt to understand the spatial structure of brightness temperature and soil moisture images when viewed at different resolutions so that we may eventually be able to evaluate the effects of sub-grid variations of these variables in our land-surface representations and weather forecasts.

  4. Speckle noise reduction in ultrasound biomedical B-scan images using discrete topological derivative.

    PubMed

    Damodaran, Nedumaran; Ramamurthy, Sivakumar; Velusamy, Sekar; Manickam, Gayathri Kanakaraj

    2012-02-01

    Over three decades, several despeckling techniques have been developed by researchers to reduce the speckle noise inherently present in ultrasound B-scan images without losing the diagnostic information. The topological derivative (TD) is the recently adopted technique in the area of biomedical image processing. In this work, we computed the topological derivative for an appropriate function associated to the ultrasound B-scan image gradient by assigning a diffusion factor k, which indicates the cost endowed to that particular image. In this article, a novel image denoising approach, called discrete topological derivative (DTD) has been implemented. The algorithm has been developed in MATLAB7.1 and tested over 200 ultrasound B-scan images of several organs such as the liver, kidney, gall bladder and pancreas. Further, the performance of the DTD algorithm has been estimated by calculating important performance metrics. A comparative study was carried out between the DTD and the traditional despeckling techniques. The calculated peak signal-to-noise ratio (PSNR) (the ratio between the maximum possible power of a signal and the power of corrupting noise that affects the fidelity of its representation) value of the DTD despeckled liver image is found to be 28 which is comparable with the outperformed speckle reducing anisotropic diffusion (SRAD) filter. SRAD filter is an edge-sensitive diffusion method for speckled images of ultrasonic and radar imaging applications. Canny edge detection and visual inspection of DTD filtered images by the trained radiologist found that the DTD algorithm preserves the hypoechoic and hyperechoic regions resulting in improved diagnosis as well as tissue characterization. PMID:22230135

  5. Image segmentation using fuzzy rules derived from K-means clusters

    Microsoft Academic Search

    Zheru Chi; Hong Yan

    1995-01-01

    Image segmentation is one of the most important steps in computerized systems for analyzing geographic map images. We present a segmentation technique, based on fuzzy rules derived from the K-means clusters, that is aimed at achieving humanlike performance. In this technique, the K-means clustering algorithm is first used to obtain mixed-class clusters of training examples, whose centers and variances are

  6. Shear-wave velocity profile and seismic input derived from ambient vibration array measurements: the case study of downtown L'Aquila

    NASA Astrophysics Data System (ADS)

    Di Giulio, Giuseppe; Gaudiosi, Iolanda; Cara, Fabrizio; Milana, Giuliano; Tallini, Marco

    2014-08-01

    Downtown L'Aquila suffered severe damage (VIII-IX EMS98 intensity) during the 2009 April 6 Mw 6.3 earthquake. The city is settled on a top flat hill, with a shear-wave velocity profile characterized by a reversal of velocity at a depth of the order of 50-100 m, corresponding to the contact between calcareous breccia and lacustrine deposits. In the southern sector of downtown, a thin unit of superficial red soils causes a further shallow impedance contrast that may have influenced the damage distribution during the 2009 earthquake. In this paper, the main features of ambient seismic vibrations have been studied in the entire city centre by using array measurements. We deployed six 2-D arrays of seismic stations and 1-D array of vertical geophones. The 2-D arrays recorded ambient noise, whereas the 1-D array recorded signals produced by active sources. Surface-wave dispersion curves have been measured by array methods and have been inverted through a neighbourhood algorithm, jointly with the H/V ambient noise spectral ratios related to Rayleigh waves ellipticity. We obtained shear-wave velocity (Vs) profiles representative of the southern and northern sectors of downtown L'Aquila. The theoretical 1-D transfer functions for the estimated Vs profiles have been compared to the available empirical transfer functions computed from aftershock data analysis, revealing a general good agreement. Then, the Vs profiles have been used as input for a deconvolution analysis aimed at deriving the ground motion at bedrock level. The deconvolution has been performed by means of EERA and STRATA codes, two tools commonly employed in the geotechnical engineering community to perform equivalent-linear site response studies. The waveform at the bedrock level has been obtained deconvolving the 2009 main shock recorded at a strong motion station installed in downtown. Finally, this deconvolved waveform has been used as seismic input for evaluating synthetic time-histories in a strong-motion target site located in the middle Aterno river valley. As a target site, we selected the strong-motion station of AQV 5 km away from downtown L'Aquila. For this site, the record of the 2009 L'Aquila main shock is available and its surface stratigraphy is adequately known making possible to propagate the deconvolved bedrock motion back to the surface, and to compare recorded and synthetic waveforms.

  7. Baseline 18F-FDG PET image derived parameters for therapy response prediction in oesophageal cancer

    E-print Network

    Paris-Sud XI, Université de

    tumour or lymph nodes [4]. A complete response occurs only in 15-30% of cases and is associated1 Baseline 18F-FDG PET image derived parameters for therapy response prediction in oesophageal LaTIM, 2 Department of Radiotherapy, CHU Morvan, Brest, France Running title: 18 F-FDG PET indices

  8. Image method for the derivation of point sources in elastostatic problems with plane interfaces

    NASA Technical Reports Server (NTRS)

    Fares, Nabil; Li, Victor C.

    1986-01-01

    An image method algorithm is presented for the derivation of point sources of elastostatics in multilayered media assuming the infinite space point source is known. Specific cases were worked out and shown to coincide with well known solutions in the literature.

  9. Properties of the Water Column and Bottom Derived from Airborne Visible Infrared Imaging Spectrometer (AVIRIS) Data

    Microsoft Academic Search

    ZhongPing Lee; Kendall L. Carder; Robert F. Chen; Thomas G. Peacock

    2001-01-01

    Using Airborne Visible Infrared Imaging Spectrometer (AVIRIS) data as an example, we show in this study that the properties of the water column and bottom of a large, shallow area can be adequately retrieved using a model-driven optimization technique. The simultaneously derived properties include bottom depth, bottom albedo, and water absorption and backscattering coefficients, which in turn could be used

  10. The benefits of using short interval satellite images to derive winds for tropical cyclones

    NASA Technical Reports Server (NTRS)

    Rodgers, E.; Gentry, R. C.; Shenk, W. E.; Oliver, V.

    1978-01-01

    During the 1975, 1976, and 1977, NOAA's National Environmental Satellite Service and NASA's Goddard Space Flight Center conducted a cooperative program to determine the optimum resolution and frequency of satellite images for deriving winds to study and forecast tropical cyclones. Rapid scan images were obtained at 7.5 minute interval from SMS-2 for hurricane Eloise and cyclone Caroline, and at 3 minute intervals from GOES-1 for tropical storms Belle, Holly, and Anita. Cloud motions were derived from these images using the Atmospheric and Oceanographic Information Processing System. Winds that were derived from the movement of upper and lower tropospheric level clouds using rapid scan data were compared with the 15 and 30 minute interval data. Greater than 10 (5) times as many clouds could be tracked to obtain winds using 3 and 7.5 minute rapid scan images as when using 15 or 30 minute interval images. A few bright areas within the central dense overcast which appeared to be moving with the winds at low levels were tracked.

  11. Development of alkoxy styrylchromone derivatives for imaging of cerebral amyloid-? plaques with SPECT.

    PubMed

    Fuchigami, Takeshi; Ogawa, Ayaka; Yamashita, Yuki; Haratake, Mamoru; Watanabe, Hiroyuki; Ono, Masahiro; Kawasaki, Masao; Yoshida, Sakura; Nakayama, Morio

    2015-08-15

    We report here the development of radioiodinated styrylchromone derivatives with alkoxy groups as single photon emission computed tomography (SPECT) imaging probes for cerebral amyloid-? (A?) plaques. Among the derivatives, the methoxy derivative 14 and the dimethoxy derivative 15 displayed relatively high affinity for the A?(1-42) aggregates with Ki values of 22 and 46nM, respectively. Fluorescent imaging demonstrated that 14 and 15 clearly labeled thioflavin-S positive A? plaques in the brain sections of Tg2576 transgenic mice. In the in vivo studies, [(125)I]14 and [(125)I]15 showed high initial brain uptake expressed as the percentage of the injected dose per gram (2.25% and 2.49% ID/g at 2min, respectively) with favorable clearance (0.12% and 0.20% ID/g at 180min, respectively) from the brain tissue of normal mice. Furthermore, in vitro autoradiography confirmed that [(125)I]15 binds thioflavin-S positive regions in Tg2576 mouse brain sections. The derivative 15 may be a potential scaffold for the development of in vivo imaging probes targeting A? plaques in the brain. In particular, further structural modifications are required to improve the compounds binding affinity for A?. PMID:26073008

  12. Input modeling

    Microsoft Academic Search

    Lawrence Leemis

    2000-01-01

    Discrete-event simulation models typically have stochastic elements that mimic the probabilistic nature of the system under consideration. Successful input modeling requires a close match between the input model and the true underlying probabilistic mechanism associated with the system. The general question considered here is how to model an element (e.g., arrival process, service times) in a discrete-event simulation given a

  13. A spatial downscaling procedure of MODIS derived actual evapotranspiration using Landsat images at central Greece

    NASA Astrophysics Data System (ADS)

    Spiliotopoulos, M.; Adaktylou, N.; Loukas, A.; Michalopoulou, H.; Mylopoulos, N.; Toulios, L.

    2013-08-01

    In this study, the Surface Energy Balance Algorithm for Land (SEBAL) was used to derive daily actual evapotranspiration (ETa) distributions from Landsat and MODIS images separately. The study area is the Lake Karla basin in Thessaly, Central Greece. Meteorological data from the archive of Center for Research and Technology, Thessaly (CERETETH) have also been used. The methodology was developed using satellite and ground data for the period of summer 2007. Landsat and MODIS imagery were combined in order to have data with high temporal and spatial resolution (downscaling). The downscaling technique applied is the output downscaling with regression between images. This technique disaggregates imagery by applying linear regression between two MODIS products to the previous or subsequent Landsat product. After the calculation of a first order linear regression between two MODIS-derived ETa maps the next step is the regression to the ETa map derived from the prior Landsat image to predict the disaggregated subsequent Landsat ETa map. The results are satisfactory, giving the general trend of ETa derived from the original SEBAL procedure.

  14. Using Geotags to Derive Rich Tag-Clouds for Image Annotation

    NASA Astrophysics Data System (ADS)

    Joshi, Dhiraj; Luo, Jiebo; Yu, Jie; Lei, Phoury; Gallagher, Andrew

    Geotagging has become popular for many multimedia applications. In this chapter, we present an integrated and intuitive system for location-driven tag suggestion, in the form of tag-clouds, for geotagged photos. Potential tags from multiple sources are extracted and weighted. Sources include points of interest (POI) tags from a public Geographic Names Information System (GNIS) database, community tags from Flickr® pictures, and personal tags shared through users' own, family, and friends' photo collections. To increase the effectiveness of GNIS POI tags, bags of place-name tags are first retrieved, clustered, and then re-ranked using a combined tf-idf and spatial distance criteria. The community tags from photos taken in the vicinity of the input geotagged photo are ranked according to distance and visual similarity to the input photo. Personal tags from other personally related photos inherently carry a significant weight due more to their high relevance than to both the generic place-name tags and community tags, and are ranked by weights that decay over time and distance differences. Finally, a rich set of the most relevant location-driven tags is presented to the user in the form of individual tag clouds under the three mentioned source categories. The tag clouds act as intuitive suggestions for tagging an input image. We also discuss quantitative and qualitative findings from a user study that we conducted. Evaluation has revealed the respective benefits of the three categories toward the effectiveness of the integrated tag suggestion system.

  15. Design, synthesis, and evaluation of cyclofenil derivatives for potential SPECT imaging agents

    Microsoft Academic Search

    Hua Zhu; Liliang Huang; Yuanqing Zhang; Xiaoping Xu; Yanhong Sun; Yu-Mei Shen

    2010-01-01

    To develop technetium- and rhenium-labeled nonsteroidal estrogen imaging agents for estrogen receptor (ER) positive breast\\u000a tumors, two groups of rhenium and technetium cyclofenil derivatives were synthesized and characterized. The binding affinities\\u000a of the rhenium complexes for ERs were determined. The tricarbonyl rhenium complex showed the highest binding affinity for\\u000a ERs (81.2 for ER?, 16.5 for ER?). Tricarbonyl technetium cyclofenil complexes

  16. Effect of detector nonlinearity and image persistence on CARS derived temperatures

    Microsoft Academic Search

    D. R. Snelling; G. J. Smallwood; T. Parameswaran

    1989-01-01

    The image persistence of self-scanning photodiode arrays (IPDA) incorporating P-20 phosphor-based intensifiers is shown to make them unsuitable for single-pulse CARS temperature measurements in turbulent combustion. Correcting CARS flame spectra for the nonlinear response of the IPDA detectors increases CARS-derived temperatures by about 3-6 percent. This error is partially offset by correcting for the perturbations in the N2 vibrational population

  17. Effect of detector nonlinearity and image persistence on CARS derived temperatures

    Microsoft Academic Search

    D. R. Snelling; G. J. Smallwood; T. Parameswaran

    1989-01-01

    The image persistence of self-scanning photodiode arrays (IPDA) incorporating P-20 phosphor-based intensifiers is shown to make them unsuitable for single-plus CARS temperature measurements in turbulent combustion. Correcting CARS flame spectra for the nonlinear response of the IPDA detectors increases CARS derived temperatures \\/approx\\/3--6%. This error is partially offset by correcting for the perturbations in the Nâ vibrational population resulting from

  18. MODIS-derived daily PAR simulation from cloud-free images and its validation

    Microsoft Academic Search

    Liangfu Chen; Yanhua Gao; Lei Yang; Qinhuo Liu; Xingfa Gu; Guoliang Tian

    2008-01-01

    In this paper, a MODIS-derived daily PAR (photosynthetically active radiation) simulation model from cloud-free image over land surface has been developed based on Bird and Riordan’s model. In this model, the total downwelling spectral surface irradiance is divided into two parts: one is beam irradiance, and another is diffuse irradiance. The attenuation of solar beam irradiance comprises scattering by the

  19. High-resolution digital elevation models derived from Viking Orbiter images: Method and comparison with Mars Orbiter Laser Altimeter

    E-print Network

    Delacourt, Christophe

    1 High-resolution digital elevation models derived from Viking Orbiter images: Method local and high-resolution digital elevation models (DEM) of Mars from Viking Orbiter images. We focus Viking Orbiter images selected according to the criteria of parallax height ratio, resolution

  20. Derivation of the scan time requirement for maintaining a consistent PET image quality

    NASA Astrophysics Data System (ADS)

    Kim, Jin Su; Lee, Jae Sung; Kim, Seok-Ki

    2015-05-01

    Objectives: the image quality of PET for larger patients is relatively poor, even though the injection dose is optimized considering the NECR characteristics of the PET scanner. This poor image quality is due to the lower level of maximum NECR that can be achieved in these large patients. The aim of this study was to optimize the PET scan time to obtain a consistent PET image quality regardless of the body size, based on the relationship between the patient specific NECR (pNECR) and body weight. Methods: eighty patients (M/F=53/27, body weight: 059 ± 1 kg) underwent whole-body FDG PET scans using a Philips GEMINI GS PET/CT scanner after an injection of 0.14 mCi/kg FDG. The relationship between the scatter fraction (SF) and body weight was determined by repeated Monte Carlo simulations using a NEMA scatter phantom, the size of which varied according to the relationship between the abdominal circumference and body weight. Using this information, the pNECR was calculated from the prompt and delayed PET sinograms to obtain the prediction equation of NECR vs. body weight. The time scaling factor (FTS) for the scan duration was finally derived to make PET images with equivalent SNR levels. Results: the SF and NECR had the following nonlinear relationships with the body weight: SF=0.15 ? body weight0.3 and NECR = 421.36 (body weight)?0.84. The equation derived for FTS was 0.01? body weight + 0.2, which means that, for example, a 120-kg person should be scanned 1.8 times longer than a 70 kg person, or the scan time for a 40-kg person can be reduced by 30%. Conclusion: the equation of the relative time demand derived in this study will be useful for maintaining consistent PET image quality in clinics.

  1. Measurement of velocity and velocity derivatives based on pattern tracking in 3D LIF images

    NASA Astrophysics Data System (ADS)

    Deusch, S.; Merava, H.; Dracos, T.; Rys, P.

    Pattern tracking in consecutive 3D LIF images based on least squares matching (LSM) of grey levels has been developed recently for velocity and velocity gradient measurements. The shortcomings of this method are clearly shown. The present article presents an improvement on this method by introducing a local multi-patch (LMP) technique through the LSM approach. The method is validated using the flow field of a turbulent channel flow obtained by direct numerical simulation (DNS) and a synthetic image with grey-level patterns. The results show that LMP matching allows the determination of the velocity and the velocity gradient fields with high accuracy including the second derivatives. Measurements of a round non-buoyant jet are presented which demonstrate the good performance of the method when applied under laboratory conditions. This method can also be applied on two-dimensional images provided that the flow is strictly two-dimensional.

  2. A multi-scale approach to imaging and Frechet derivatives in wave-equation tomography

    NASA Astrophysics Data System (ADS)

    de Hoop, M. V.; van der Hilst, R. D.; Salo, M.; Brytik, V.; Smith, H.; Uhlmann, G.

    2007-12-01

    We discuss a common (PDE) framework for wave-equation transmission and reflection tomography. The development of the associated imaging procedures and optimization, via adjoint states, involves the Frechet derivatives of the solution operators modelling the different types of data. We present the principles of a multi- scale approach to constructing these Frechet derivatives, using curvelets, in velocity models of limited smoothness. The Frechet derivatives would directly appear in the adjoint state formulation based on `fitting' the data, but here we focus on different functionals for optimization, the sensitivity kernels of which can be viewed as generalizations of their ray-geometric counterparts. We discuss commonalities with the multi-scale decomposition of linearized inverse scattering with the generalized Radon transform. The constructions can be naturally integrated with sparsity constrained optimization via multi-scale representations of the model perturbation.

  3. Derivative-based scale invariant image feature detector with error resilience.

    PubMed

    Mainali, Pradip; Lafruit, Gauthier; Tack, Klaas; Van Gool, Luc; Lauwereins, Rudy

    2014-05-01

    We present a novel scale-invariant image feature detection algorithm (D-SIFER) using a newly proposed scale-space optimal 10th-order Gaussian derivative (GDO-10) filter, which reaches the jointly optimal Heisenberg's uncertainty of its impulse response in scale and space simultaneously (i.e., we minimize the maximum of the two moments). The D-SIFER algorithm using this filter leads to an outstanding quality of image feature detection, with a factor of three quality improvement over state-of-the-art scale-invariant feature transform (SIFT) and speeded up robust features (SURF) methods that use the second-order Gaussian derivative filters. To reach low computational complexity, we also present a technique approximating the GDO-10 filters with a fixed-length implementation, which is independent of the scale. The final approximation error remains far below the noise margin, providing constant time, low cost, but nevertheless high-quality feature detection and registration capabilities. D-SIFER is validated on a real-life hyperspectral image registration application, precisely aligning up to hundreds of successive narrowband color images, despite their strong artifacts (blurring, low-light noise) typically occurring in such delicate optical system setups. PMID:24723627

  4. Bioluminescence Reporter Gene Imaging Characterize Human Embryonic Stem Cell-Derived Teratoma Formation

    PubMed Central

    Su, Weijun; Zhou, Manqian; Zheng, Yizhou; Fan, Yan; Han, Zhongchao; Kong, Deling; Wu, Joseph C.; Xiang, Rong; Li, Zongjin

    2011-01-01

    Human embryonic stem (hES) cells are capable of differentiation into virtually all cell types and hold tremendous potential as cell sources for regenerative therapies. However, teratoma formation can be the main obstacle for hES cells therapy. In order to understand the biology and physiology of hES cells teratoma formation, we investigated the angiogenic process within teratomas and characterized teratoma cells. In this study, hES cells transduced with double fusion reporter gene that consists of firefly luciferase and enhanced green fluorescent protein (Fluc-eGFP) were injected into hind limbs of SCID mice and performed longitudinal bioluminescence imaging on these animals. To test angiogenic contribution of teratoma from host or hES cells, human and mouse endothelial cells marker CD31 was stained respectively. To further explore the characterization of teratoma derived cells, flow cytometry analysis was carried out and GFP+/SSEA-4+ cells were isolated and subcultured. Then, we re-injected the isolated GFP+/SSEA-4+ teratoma cells into SCID mice and observed by imaging. Our results show that the reporter gene imaging is an ideal technology for monitoring long-term stem cell viability, death, and proliferation. Teratomas contained vasculatures are from hES cells and host. hESCs derived teratomas express a high level of undifferentiated marker SSEA-4 and CD56, and subcultured GFP+/SSEA-4+ cells had similar expression pattern comparing to undifferentiated hES cells, except for a very high level of CD56 and a little lower expression of undifferentiated markers, such as SSEA-3, SSEA-4, TRA-1-60, and TRA-1-81. Moreover, the SSEA-4+ teratoma cells can form teratomas in SCID mice, and this type teratomas grow at a lower rate compared to teratomas derived from hES cells, and are more differentiated. PMID:21328457

  5. Synthesis of fluorescent derivatives of praziquantel: cell-imaging and interaction with Schistosoma japonicum cercariae.

    PubMed

    Xie, Yunzhi; Li, Yibao; Wu, Yongquan; Liu, Chunhua; Li, Xiaokang; Li, Xun; Fan, Xiaolin

    2013-09-28

    Schistosomiasis is one of the most burdensome of the neglected tropical diseases. Praziquantel is a recommended drug for treatment against all forms of schistosomiasis. To investigate the interaction between praziquantel and Schistosoma japonicum cercariae, two praziquantel derivatives (PZQ-2 and PZQ-3) and one praziquantel fluorescent derivative (PZQ-5) have been synthesized and characterized using nuclear magnetic resonance spectroscopy (NMR) and MS spectra. The cytotoxicity of PZQ-2, PZQ-3 and PZQ-5 was measured by performing the methyl thiazolyl tetrazolium (MTT) assay. The cell viability for them shows that the three compounds exhibit low cytotoxicity to HeLa cells. Cell imaging experiments demonstrate that PZQ-5 is biocompatible and cell-permeable, which indicates that PZQ-5 is suitable for studying their interaction. Confocal fluorescence microscopy revealed that PZQ-5 is mainly located at the cercarial tegument, which leads to the death of cercariae with the increase in time. PMID:23925274

  6. Two-dimensional superresolution multiple-input multiple-output and inverse synthetic aperture radar imaging based on spatial frequency ambiguity resolving

    NASA Astrophysics Data System (ADS)

    Yang, Jianchao; Su, Weimin; Gu, Hong

    2015-01-01

    Combining multiple-input multiple-output (MIMO) radar and inverse synthetic aperture radar (ISAR) techniques can reduce the number of antennas used and shorten the radar integrated time compared with the single-channel ISAR for the same cross-range resolution. In existing MIMO-ISAR processing, the echoes of different sensors are rearranged into an equivalent single-channel ISAR signal. A new method without echo rearrangement is proposed for two-dimensional (2-D) MIMO-ISAR imaging. A 2-D frequency estimation algorithm based on Unitary ESPRIT and projection transformation is used to obtain the spatial and Doppler frequencies of scatterers, and a high cross-range resolution can be achieved. The relationship between the two frequencies is exploited to resolve the ambiguity of spatial frequency. The analysis and simulation results show that, compared with the existing method, the proposed method can decrease the relative rotation angle (or integrated time) required for imaging. Thus, this method is more suitable for imaging targets with limited rotation or high maneuvering.

  7. Hierarchy of Electronic Properties of Chemically Derived and Pristine Graphene Probed by Microwave Imaging

    SciTech Connect

    Kundhikanjana, W.

    2010-06-02

    Local electrical imaging using microwave impedance microscope is performed on graphene in different modalities, yielding a rich hierarchy of the local conductivity. The low-conductivity graphite oxide and its derivatives show significant electronic inhomogeneity. For the conductive chemical graphene, the residual defects lead to a systematic reduction of the microwave signals. In contrast, the signals on pristine graphene agree well with a lumped-element circuit model. The local impedance information can also be used to verify the electrical contact between overlapped graphene pieces.

  8. COLLINARUS: collection of image-derived non-linear attributes for registration using splines

    NASA Astrophysics Data System (ADS)

    Chappelow, Jonathan; Bloch, B. Nicolas; Rofsky, Neil; Genega, Elizabeth; Lenkinski, Robert; DeWolf, William; Viswanath, Satish; Madabhushi, Anant

    2009-02-01

    We present a new method for fully automatic non-rigid registration of multimodal imagery, including structural and functional data, that utilizes multiple texutral feature images to drive an automated spline based non-linear image registration procedure. Multimodal image registration is significantly more complicated than registration of images from the same modality or protocol on account of difficulty in quantifying similarity between different structural and functional information, and also due to possible physical deformations resulting from the data acquisition process. The COFEMI technique for feature ensemble selection and combination has been previously demonstrated to improve rigid registration performance over intensity-based MI for images of dissimilar modalities with visible intensity artifacts. Hence, we present here the natural extension of feature ensembles for driving automated non-rigid image registration in our new technique termed Collection of Image-derived Non-linear Attributes for Registration Using Splines (COLLINARUS). Qualitative and quantitative evaluation of the COLLINARUS scheme is performed on several sets of real multimodal prostate images and synthetic multiprotocol brain images. Multimodal (histology and MRI) prostate image registration is performed for 6 clinical data sets comprising a total of 21 groups of in vivo structural (T2-w) MRI, functional dynamic contrast enhanced (DCE) MRI, and ex vivo WMH images with cancer present. Our method determines a non-linear transformation to align WMH with the high resolution in vivo T2-w MRI, followed by mapping of the histopathologic cancer extent onto the T2-w MRI. The cancer extent is then mapped from T2-w MRI onto DCE-MRI using the combined non-rigid and affine transformations determined by the registration. Evaluation of prostate registration is performed by comparison with the 3 time point (3TP) representation of functional DCE data, which provides an independent estimate of cancer extent. The set of synthetic multiprotocol images, acquired from the BrainWeb Simulated Brain Database, comprises 11 pairs of T1-w and proton density (PD) MRI of the brain. Following the application of a known warping to misalign the images, non-rigid registration was then performed to recover the original, correct alignment of each image pair. Quantitative evaluation of brain registration was performed by direct comparison of (1) the recovered deformation field to the applied field and (2) the original undeformed and recovered PD MRI. For each of the data sets, COLLINARUS is compared with the MI-driven counterpart of the B-spline technique. In each of the quantitative experiments, registration accuracy was found to be significantly (p < 0.05) for COLLINARUS compared with MI-driven B-spline registration. Over 11 slices, the mean absolute error in the deformation field recovered by COLLINARUS was found to be 0.8830 mm.

  9. Novel Positively Charged Nanoparticle Labeling for In Vivo Imaging of Adipose Tissue-Derived Stem Cells

    PubMed Central

    Yukawa, Hiroshi; Nakagawa, Shingo; Yoshizumi, Yasuma; Watanabe, Masaki; Saito, Hiroaki; Miyamoto, Yoshitaka; Noguchi, Hirofumi; Oishi, Koichi; Ono, Kenji; Sawada, Makoto; Kato, Ichiro; Onoshima, Daisuke; Obayashi, Momoko; Hayashi, Yumi; Kaji, Noritada; Ishikawa, Tetsuya; Hayashi, Shuji; Baba, Yoshinobu

    2014-01-01

    Stem cell transplantation has been expected to have various applications for regenerative medicine. However, in order to detect and trace the transplanted stem cells in the body, non-invasive and widely clinically available cell imaging technologies are required. In this paper, we focused on magnetic resonance (MR) imaging technology, and investigated whether the trimethylamino dextran-coated magnetic iron oxide nanoparticle -03 (TMADM-03), which was newly developed by our group, could be used for labeling adipose tissue-derived stem cells (ASCs) as a contrast agent. No cytotoxicity was observed in ASCs transduced with less than 100 µg-Fe/mL of TMADM-03 after a one hour transduction time. The transduction efficiency of TMADM-03 into ASCs was about four-fold more efficient than that of the alkali-treated dextran-coated magnetic iron oxide nanoparticle (ATDM), which is a major component of commercially available contrast agents such as ferucarbotran (Resovist), and the level of labeling was maintained for at least two weeks. In addition, the differentiation ability of ASCs labeled with TMADM-03 and their ability to produce cytokines such as hepatocyte growth factor (HGF), vascular endothelial growth factor (VEGF) and prostaglandin E2 (PGE2), were confirmed to be maintained. The ASCs labeled with TMADM-03 were transplanted into the left kidney capsule of a mouse. The labeled ASCs could be imaged with good contrast using a 1T MR imaging system. These data suggest that TMADM-03 can therefore be utilized as a contrast agent for the MR imaging of stem cells. PMID:25365191

  10. Shape and rotational elements of comet 67P/ Churyumov-Gerasimenko derived by stereo-photogrammetric analysis of OSIRIS NAC image data

    NASA Astrophysics Data System (ADS)

    Preusker, Frank; Scholten, Frank; Matz, Klaus-Dieter; Roatsch, Thomas; Willner, Konrad; Hviid, Stubbe; Knollenberg, Jörg; Kührt, Ekkehard; Sierks, Holger

    2015-04-01

    The European Space Agency's Rosetta spacecraft is equipped with the OSIRIS imaging system which consists of a wide-angle and a narrow-angle camera (WAC and NAC). After the approach phase, Rosetta was inserted into a descent trajectory of comet 67P/Churyumov-Gerasimenko (C-G) in early August 2014. Until early September, OSIRIS acquired several hundred NAC images of C-G's surface at different scales (from ~5 m/pixel during approach to ~0.9 m/pixel during descent). In that one month observation period, the surface was imaged several times within different mapping sequences. With the comet's rotation period of ~12.4 h and the low spacecraft velocity (< 1 m/s), the entire NAC dataset provides multiple NAC stereo coverage, adequate for stereo-photogrammetric (SPG) analysis towards the derivation of 3D surface models. We constrained the OSIRIS NAC images with our stereo requirements (15° < stereo angles < 45°, incidence angles <85°, emission angles <45°, differences in illumination < 10°, scale better than 5 m/pixel) and extracted about 220 NAC images that provide at least triple stereo image coverage for the entire illuminated surface in about 250 independent multi-stereo image combinations. For each image combination we determined tie points by multi-image matching in order to set-up a 3D control network and a dense surface point cloud for the precise reconstruction of C-G's shape. The control point network defines the input for a stereo-photogrammetric least squares adjustment. Based on the statistical analysis of adjustments we first refined C-G's rotational state (pole orientation and rotational period) and its behavior over time. Based upon this description of the orientation of C-G's body-fixed reference frame, we derived corrections for the nominal navigation data (pointing and position) within a final stereo-photogrammetric block adjustment where the mean 3D point accuracy of more than 100 million surface points has been improved from ~10 m to the sub-meter range. We finally applied point filtering and interpolation techniques to these surface 3D points and show the resulting SPG-based 3D surface model with a lateral sampling rate of about 2 m.

  11. A complementary dual-slope ADC with high frame rate and wide input range for fast X-ray imaging

    NASA Astrophysics Data System (ADS)

    Lee, Daehee; Cho, Minsik; Kang, Dong-Uk; Kim, Myung Soo; Kim, Hyunduk; Cho, Gyuseong

    2014-02-01

    The single-slope analog-to-digital converter (SS-ADC) is the most commonly used column-level ADC for high-speed industrial, complementary metal-oxide semiconductor (CMOS)-based X-ray image sensors because of its small chip area (the width of a pixel), its simple circuit structure, and its low power consumption. However, it generally has a long conversion time, so we propose an innovative design: a complimentary dual-slope ADC (CDS-ADC) that uses two opposite ramp signals instead of a single ramp to double the conversion speed. This CDS-ADC occupies only 15% more area than the original SS-ADC. A prototype 12-bit CDS-ADC and a 12-bit SS-ADC were fabricated using a 0.35-µm 1P 4M CMOS process. During comparison of the two, the measured maximum differential non-linearity (DNL) of the CDS-ADC was a 0.49 least significant bit (LSB), the maximum integral non-linearity (INL) was a 0.43 LSB, the effective number of bits (ENOB) was 9.18 bits, and the figure of merit (FOM) was 0.03 pJ/conversion. The total power consumption was 0.031 uW. The conversion time of the new CDS-ADC was half that of the SS-ADC. The proposed dual-slope concept can be extended to further multiply the conversion speed by using multiple pairs of dual-slope ramps.

  12. Derivatives of dibenzothiophene for PET imaging of ?7-Nicotinic Acetylcholine Receptors

    PubMed Central

    Gao, Yongjun; Kellar, Kenneth J.; Yasuda, Robert P.; Tran, Thao; Xiao, Yingxian; Dannals, Robert F.; Horti, Andrew G.

    2013-01-01

    A new series of derivatives of 3-(1,4-diazabicyclo[3.2.2]nonan-4-yl)dibenzo[b,d]thiophene 5,5-dioxide with high binding affinities and selectivity for ?7-nicotinic acetylcholine receptors (?7-nAChRs) (Ki = 0.4 – 20 nM) has been synthesized for PET imaging of ?7-nAChRs. Two radiolabeled members of the series [18F]7a (Ki = 0.4 nM) and [18F]7c (Ki = 1.3 nM) were synthesized. [18F]7a and [18F]7c readily entered the mouse brain and specifically labeled ?7-nAChRs. The ?7-nAChR selective ligand 1 (SSR180711) blocked the binding of [18F]7a in the mouse brain in a dose-dependent manner. The mouse blocking studies with non-?7-nAChR CNS drugs demonstrated that [18F]7a is highly ?7-nAChR selective. In agreement with its binding affinity the binding potential of [18F]7a (BPND = 5.3 – 8.0) in control mice is superior to previous ?7-nAChR PET radioligands. Thus, [18F]7a displays excellent imaging properties in mice and has been chosen for further evaluation as a potential PET radioligand for imaging of ?7-nAChR in non-human primates. PMID:24050653

  13. Derivatives of dibenzothiophene for positron emission tomography imaging of ?7-nicotinic acetylcholine receptors.

    PubMed

    Gao, Yongjun; Kellar, Kenneth J; Yasuda, Robert P; Tran, Thao; Xiao, Yingxian; Dannals, Robert F; Horti, Andrew G

    2013-10-10

    A new series of derivatives of 3-(1,4-diazabicyclo[3.2.2]nonan-4-yl)dibenzo[b,d]thiophene 5,5-dioxide with high binding affinities and selectivity for ?7-nicotinic acetylcholine receptors (?7-nAChRs) (Ki = 0.4-20 nM) has been synthesized for positron emission tomography (PET) imaging of ?7-nAChRs. Two radiolabeled members of the series [(18)F]7a (Ki = 0.4 nM) and [(18)F]7c (Ki = 1.3 nM) were synthesized. [(18)F]7a and [(18)F]7c readily entered the mouse brain and specifically labeled ?7-nAChRs. The ?7-nAChR selective ligand 1 (SSR180711) blocked the binding of [(18)F]7a in the mouse brain in a dose-dependent manner. The mouse blocking studies with non-?7-nAChR central nervous system drugs demonstrated that [(18)F]7a is highly ?7-nAChR selective. In agreement with its binding affinity the binding potential of [(18)F]7a (BPND = 5.3-8.0) in control mice is superior to previous ?7-nAChR PET radioligands. Thus, [(18)F]7a displays excellent imaging properties in mice and has been chosen for further evaluation as a potential PET radioligand for imaging of ?7-nAChR in non-human primates. PMID:24050653

  14. Thermally activated delayed fluorescence of fluorescein derivative for time-resolved and confocal fluorescence imaging.

    PubMed

    Xiong, Xiaoqing; Song, Fengling; Wang, Jingyun; Zhang, Yukang; Xue, Yingying; Sun, Liangliang; Jiang, Na; Gao, Pan; Tian, Lu; Peng, Xiaojun

    2014-07-01

    Compared with fluorescence imaging utilizing fluorophores whose lifetimes are in the order of nanoseconds, time-resolved fluorescence microscopy has more advantages in monitoring target fluorescence. In this work, compound DCF-MPYM, which is based on a fluorescein derivative, showed long-lived luminescence (22.11 ?s in deaerated ethanol) and was used in time-resolved fluorescence imaging in living cells. Both nanosecond time-resolved transient difference absorption spectra and time-correlated single-photon counting (TCSPC) were employed to explain the long lifetime of the compound, which is rare in pure organic fluorophores without rare earth metals and heavy atoms. A mechanism of thermally activated delayed fluorescence (TADF) that considers the long wavelength fluorescence, large Stokes shift, and long-lived triplet state of DCF-MPYM was proposed. The energy gap (?EST) of DCF-MPYM between the singlet and triplet state was determined to be 28.36 meV by the decay rate of DF as a function of temperature. The ?E(ST) was small enough to allow efficient intersystem crossing (ISC) and reverse ISC, leading to efficient TADF at room temperature. The straightforward synthesis of DCF-MPYM and wide availability of its starting materials contribute to the excellent potential of the compound to replace luminescent lanthanide complexes in future time-resolved imaging technologies. PMID:24936960

  15. Resolution and shutter speed measurements of an MCPII with a 270-ps whole image shutter for a point-source input

    SciTech Connect

    Thomas, M.C. [Special Technologies Lab., Santa Barbara, CA (United States); Yates, G.J. [Los Alamos National Lab., NM (United States); Zagarino, P. [Sharpenit, Ellwood, CA (United States)

    1995-07-01

    The modulation transfer function (MF) of a shuttered, 18-mm-diameter, proximity-focused microchemical-plate image intensifier (MCPII) was measured as a function of time in the shutter sequence. Electrical gate pulses were delivered to the MCPII with microstrip impedance transformers for reduced pulse dispersion and reflections. Using 30 ps FWHM, 600 nm pulses from a sync-pumped dye, argon-ion laser as a probe, the MCPII`s shutter speed for point-source (6-{mu}m-diameter) illumination and 230 ps FWHM, {minus}590 V gate pulses was measured to be between 200 and 250 ps FWHM. The MF of the MCPII was measured by analyzing the point spread function (PSF) for inputs at several different locations on the MCPII and at different times in the shuttering sequence. The best 50% MF resolution of 16.2 lp/mm was found with illumination near the edge where the gate pulse enters the MCPII and at 120 ps into the shutter sequence. The whole image (18-mm-diameter) shutter speed (off-to-off) of the MCPII was measured to be 270 ps.

  16. Effective and robust infrared small target detection with the fusion of polydirectional first order derivative images under facet model

    NASA Astrophysics Data System (ADS)

    Zhu, Bing; Xin, Yunhong

    2015-03-01

    The robust detection of IR small target acts as one of the key techniques in the infrared search and tracking system (IRSTS). This paper presents a new method of small-target detection which formulates the problem as the detection of Gaussian-like spot. Initially, the amendatory first-order directional derivative (AFODD) based on facet model is applied to get the polydirectional derivative IR images, and the direction information of targets is reserved in these images. Then, the AFODD images are fused together to ensure the robustness and effectiveness of target detection. At last, the Principal Component Analysis (PCA) method is carried out to make targets in the fusion image more prominent, so that they can be extracted out by a simple threshold segmentation. Experiment results show that the presented method performs well even in the IR images with complex backgrounds.

  17. A study on the topological derivative-based imaging of thin electromagnetic inhomogeneities in limited-aperture problems

    NASA Astrophysics Data System (ADS)

    Ahn, Chi Young; Jeon, Kiwan; Ma, Yong-Ki; Park, Won-Kwang

    2014-10-01

    The topological derivative-based non-iterative imaging algorithm has demonstrated its applicability in limited-aperture inverse scattering problems. However, this has been confirmed through many experimental simulation results, and the reason behind this applicability has not been satisfactorily explained. In this paper, we identify the mathematical structure and certain properties of topological derivatives for the imaging of two-dimensional crack-like thin penetrable electromagnetic inhomogeneities that are completely embedded in a homogeneous material. To this end, we establish a relationship with an infinite series of Bessel functions of integer order of the first kind. Based on the derived structure, we discover a necessary condition for applying topological derivatives in limited-aperture inverse scattering problems, and thus confirm why topological derivatives can be applied. Furthermore, we analyze the structure of multi-frequency topological derivative, and identify why this improves the single-frequency topological derivative in limited-aperture inverse scattering problems. Various numerical simulations are conducted with noisy data, and the results support the derived structure and exhibit certain properties of single- and multi-frequency topological derivatives.

  18. Tectonic features on Saturns satellites Dione and Rhea: Morphology and stratigraphy derived from Cassini ISS images

    NASA Astrophysics Data System (ADS)

    Wagner, R. J.; Neukum, G.; Stephan, K.; Giese, B.; Roatsch, T.; Wolf, U.; Porco, C. C.

    2009-04-01

    Introduction: The second- and fourth-largest satellites of Saturn, Rhea (1528 km in diameter) and Dione (1124 km), harbor old, densely cratered surfaces but also show evidence of resurfacing through tectonism in the images taken by the two ISS cameras aboard the Cassini spacecraft since July 2004. On Dione, tectonic features are more widespread than on Rhea implying that geologic activity has been going on for a longer time, whereas on Rhea tectonic activity may have ceased early in its history. The tectonic inventory of both satellites incorporates (a) troughs (graben), (b) scarps, (c) ridges, (d) lineaments, and (e) plateaus on Dione. Procedure: In this paper we focus on the stratigraphic sequence of events which created these tectonic landforms, independent of specific stress origins which are the topic of further work. Our investigation is based on the global ISS image coverage at regional (150 - 500 m/pxl), and, for selected target areas, at high-resolution scale (< 50 m/pxl). Relative ages of tectonic landforms are constrained by (1) cross-cutting relationships, (2) by their degree of degradation, (3) and by their superimposed crater frequency. On Dione, the image resolutions are sufficient to examine stratigraphic relationships between tectonic features while on Rhea the areas affected by tectonism could not yet be observed so far at regional or high resolution. Stratigraphy: On both satellites, densely cratered plains are the dominant geologic units with inferred high ages of ~ 3 - 4.2 Gyr from cratering chronology models. Degraded, densely cratered graben in the high northern and southern latitudes on Dione were formed early in its history. On Rhea, ridges seen in stereo data also appear to be rather old features. Troughs and graben on Rhea's trailing hemisphere could be old, but further regional- and high-resolution imaging is needed for detailed investigations. On Dione's trailing hemisphere, a stratigraphic sequence of horsts, graben and scarps has been derived by mutual crosscutting and truncation. Three age groups can be observed: (1) Clusium and Carthage Fossae are the oldest, truncated by (2) Eurotas and Palatine Chasmata which in turn were truncated by (3) Padua Chasmata representing the youngest set of troughs. Time and duration of tectonic activity on the two satellites is difficult to determine because of uncertainties in cratering chronology models. In the Eurotas Chasmata region, for example, cratering models suggest either older tectonism of about ~ 3 Gyr, or even younger events of about ~ 1 Gyr. No age determinations of tectonic events on Rhea have been made so far due to lack of sufficient image coverage.

  19. Changes in Thermospheric O/N2 Derived from UVI Auroral Images

    NASA Technical Reports Server (NTRS)

    Germany, G. A.; Swift, W.; Richard, P. G.; Parks, G.; Brittnacher, M.; Spann, J. F., Jr.

    1997-01-01

    A rigorous test of our understanding of the coupled ionosphere-thermosphere and its response to geomagnetic storms is the ability to reproduce observed storm effects as seen in the ionosphere and neutral atmosphere. The concept of compositional change is central to studies of thermosphere response to storm conditions. In particular, information about compositional change within the highly dynamic auroral region is limited. The Ultraviolet Imager (UVI) is designed to view the full auroral region using five filters to isolate emissions from atomic oxygen (1304 and 1356) and N2 LBH. This spectral resolution allows auroral energy characteristics to be derived by two separate methods from examining ratios of observed intensities (OI 1356/LBHL or LBHS/LBHL). The LBHS:LBHL ratio is typically used as the mean energy diagnostic since the OI 1356 emission is dependent on changes in the atomic oxygen density, and these changes relative to N2 can be large. However, once the mean energy has been specified by the LBH ratio, this variability in OI 1356 emission can be exploited as a direct diagnostic of total atomic oxygen column density. This opens the potential of using UVI images to monitor the temporal and spatial response of thermospheric O to high latitude forcing within the auroral regions. Initial results of this type of analysis will be presented along with discussion of its limitations and capabilities.

  20. Automatic Identification and Truncation of Boundary Outlets in Complex Imaging-Derived Biomedical Geometries

    SciTech Connect

    Jiao, Xiangmin; Einstein, Daniel R.; Dyedov, Volodymyr; Carson, James P.

    2009-09-01

    Fast and accurate reconstruction of imaging-derived geometries and subsequent quality mesh generation for biomedical computation are enabling technologies for both clinical and research simulations. Often, the transformation of image to mesh is the rate-limiting step, requiring arduous manual manipulations. A challenging part of this process is the introduction of computable, orthogonal boundary patches, namely the outlets, into treed structures, such as vasculature, arterial or airway trees. Herein, we present efficient and robust algorithms for automatically identifying and truncating the outlets for complex biomedical geometries. Our approach is based on a conceptual decomposition of objects into three different types of local structures, including tips, segments, and branches, where the tips determine the outlets. We define the tips by introducing a novel geometric concept called the average interior center of curvature (AICC), and identify those that are physically stable and numerically noise resistant through successive inflation and deflation tests. We compute well-defined orthogonal planes, which truncate the tips into outlets. The rims of the outlets are then connected into curves, and the outlets are then closed using Delaunay triangulation with the curves as the boundary constraints. Our approach is efficient, with near linear time complexity. We illustrate the effectiveness and robustness of our approach with a variety of complex lung and coronary artery geometries.

  1. Synthesis and characterization of water-soluble polythiophene derivatives for cell imaging.

    PubMed

    Wang, Fengyan; Li, Meng; Wang, Bing; Zhang, Jiangyan; Cheng, Yongqiang; Liu, Libing; Lv, Fengting; Wang, Shu

    2015-01-01

    In this work, four water-soluble polythiophene derivatives (PT, PT-DDA, PT-ADA, and PT-ADA-PPR) with different pendant moieties were synthesized via oxidative copolymerization by FeCl3. By increasing the hydrophobic ability of side chain moieties, there is a gradually blue shift for the maximum absorption wavelength and red shift for the maximum emission wavelength, a reducing trend for fluorescence quantum yields, a growing trend for Stokes shift, and an increasing trend for the mean sizes in the order of PT, PT-ADA, and PT-DDA. All the synthesized polymers show low toxicity and good photostability and accumulate in the lysosomes of A549 cells. Furthermore, the introduction of porphyrin group to PT-ADA side chain (PT-ADA-PPR) broadens the absorption and emission ranges of PT-ADA. PT-ADA-PPR could be excited at two different excitation wavelengths (488?nm and 559?nm) and exhibits two emission pathways, and dual-color fluorescence images (orange and red) of PT-ADA-PPR accumulated in A549 cells are observed. Thus, PT-ADA-PPR could be used as an excellent dual-color fluorescent and lysosome-specific imaging material. PMID:25557020

  2. Synthesis and Characterization of Water-Soluble Polythiophene Derivatives for Cell Imaging

    NASA Astrophysics Data System (ADS)

    Wang, Fengyan; Li, Meng; Wang, Bing; Zhang, Jiangyan; Cheng, Yongqiang; Liu, Libing; Lv, Fengting; Wang, Shu

    2015-01-01

    In this work, four water-soluble polythiophene derivatives (PT, PT-DDA, PT-ADA, and PT-ADA-PPR) with different pendant moieties were synthesized via oxidative copolymerization by FeCl3. By increasing the hydrophobic ability of side chain moieties, there is a gradually blue shift for the maximum absorption wavelength and red shift for the maximum emission wavelength, a reducing trend for fluorescence quantum yields, a growing trend for Stokes shift, and an increasing trend for the mean sizes in the order of PT, PT-ADA, and PT-DDA. All the synthesized polymers show low toxicity and good photostability and accumulate in the lysosomes of A549 cells. Furthermore, the introduction of porphyrin group to PT-ADA side chain (PT-ADA-PPR) broadens the absorption and emission ranges of PT-ADA. PT-ADA-PPR could be excited at two different excitation wavelengths (488 nm and 559 nm) and exhibits two emission pathways, and dual-color fluorescence images (orange and red) of PT-ADA-PPR accumulated in A549 cells are observed. Thus, PT-ADA-PPR could be used as an excellent dual-color fluorescent and lysosome-specific imaging material.

  3. Signal filtering of daily cloud types' trends as derived from satellite images

    NASA Astrophysics Data System (ADS)

    Dim, Jules R.; Murakami, Hiroshi

    2011-03-01

    The relationship between the intensity functions of contiguous pixels of an image is used on daily global clouds satellite data to extract local edge gradients for cloud types' classification. The images are cloud top temperatures (CTT) derived from the National Oceanic and Atmospheric Administration/Advanced Very-High-Resolution Radiometer (NOAA-AVHRR) satellite observations. The cloud type classification method used is a histogram-based gradient scheme described as the occurrence of low, mid or high edge gradients in a block of pixels. The distribution of these cloud types is analyzed, then, the consistency of the monthly variations of the cloud type amount estimation is evaluated. A clear dependence of the cloud type amount signal on the solar zenith angle is noticeable. This dependence, due to the gradual satellite drift, is removed through a filtering process using the empirical mode decomposition (EMD) method. The EMD component, associated with the drift or the solar zenith angle change, is filtered out. The cloud types' amount series corrected show a substantial improvement in their trends.

  4. Ladar image recognition using synthetically derived discrete phase-amplitude filters in an optical correlator

    NASA Astrophysics Data System (ADS)

    Calloway, David; Goldstein, Dennis H.

    2002-03-01

    Correlation filters using computer-generated laser radar imagery have been constructed. This paper describes how the filters were constructed and reports correlating result with the synthetic imagery used in the training set, with real ladar imagery of equivalent targets, and with real ladar imagery of false targets. A comprehensive set of images was collected on the Eglin Test Range using a direct-detect scanning ladar mounted on a 100-meter tower. Various targets were placed on a large turntable and ladar range and intensity data were collected at various aspect and depression angles. The Irma scene generation software package was then used to generate synthetic ladar imagery for these targets at a similar set of range, aspect, and depression angles. Several different techniques were used to generate the filters and to process the imagery used in this research. This paper describes one of the most successful techniques. The paper provides details on the iterative approach used to generate composite filters, describes how they were applied, and compares the results produced from synthetic and real target imagery. This experiment was considered a success since the synthetically derived filters were capable of recognizing images of real targets while rejecting false targets.

  5. Magnetic resonance velocity imaging derived pressure differential using control volume analysis

    PubMed Central

    2011-01-01

    Background Diagnosis and treatment of hydrocephalus is hindered by a lack of systemic understanding of the interrelationships between pressures and flow of cerebrospinal fluid in the brain. Control volume analysis provides a fluid physics approach to quantify and relate pressure and flow information. The objective of this study was to use control volume analysis and magnetic resonance velocity imaging to non-invasively estimate pressure differentials in vitro. Method A flow phantom was constructed and water was the experimental fluid. The phantom was connected to a high-resolution differential pressure sensor and a computer controlled pump producing sinusoidal flow. Magnetic resonance velocity measurements were taken and subsequently analyzed to derive pressure differential waveforms using momentum conservation principles. Independent sensor measurements were obtained for comparison. Results Using magnetic resonance data the momentum balance in the phantom was computed. The measured differential pressure force had amplitude of 14.4 dynes (pressure gradient amplitude 0.30 Pa/cm). A 12.5% normalized root mean square deviation between derived and directly measured pressure differential was obtained. These experiments demonstrate one example of the potential utility of control volume analysis and the concepts involved in its application. Conclusions This study validates a non-invasive measurement technique for relating velocity measurements to pressure differential. These methods may be applied to clinical measurements to estimate pressure differentials in vivo which could not be obtained with current clinical sensors. PMID:21414222

  6. Plasma Distribution in Mercury's Magnetosphere Derived from MESSENGER Magnetometer and Fast Imaging Plasma Spectrometer Observations

    NASA Technical Reports Server (NTRS)

    Korth, Haje; Anderson, Brian J.; Gershman, Daniel J.; Raines, Jim M.; Slavin, James A.; Zurbuchen, Thomas H.; Solomon, Sean C.; McNutt, Ralph L.

    2014-01-01

    We assess the statistical spatial distribution of plasma in Mercury's magnetosphere from observations of magnetic pressure deficits and plasma characteristics by the MErcury Surface, Space ENvironment, GEochemistry, and Ranging (MESSENGER) spacecraft. The statistical distributions of proton flux and pressure were derived from 10months of Fast Imaging Plasma Spectrometer (FIPS) observations obtained during the orbital phase of the MESSENGER mission. The Magnetometer-derived pressure distributions compare favorably with those deduced from the FIPS observations at locations where depressions in the magnetic field associated with the presence of enhanced plasma pressures are discernible in the Magnetometer data. The magnitudes of the magnetic pressure deficit and the plasma pressure agree on average, although the two measures of plasma pressure may deviate for individual events by as much as a factor of approximately 3. The FIPS distributions provide better statistics in regions where the plasma is more tenuous and reveal an enhanced plasma population near the magnetopause flanks resulting from direct entry of magnetosheath plasma into the low-latitude boundary layer of the magnetosphere. The plasma observations also exhibit a pronounced north-south asymmetry on the nightside, with markedly lower fluxes at low altitudes in the northern hemisphere than at higher altitudes in the south on the same field line. This asymmetry is consistent with particle loss to the southern hemisphere surface during bounce motion in Mercury's offset dipole magnetic field.

  7. Brain imaging: Reduced sensitivity of RARE-derived techniques to susceptibility effects

    SciTech Connect

    Reimer, P.; Allkemper, T.; Schuierer, G.; Peters, P.E. [Westfalian Wilhelms-Univ. Muenster, Muenster (Germany)] [Westfalian Wilhelms-Univ. Muenster, Muenster (Germany)

    1996-03-01

    Our goal was to evaluate the decreased sensitivity of RARE-derived pulse sequences to susceptibility effects. A variety of RARE-derived T2-weighted fast SE echo (FSE) sequences with echo trains from 6 to 16 were compared with conventional SE (CSE) sequences by means of MRI in phantoms (iron oxides), volunteers (n = 10), and patients (n = 13) with old hemorrhagic brain lesions. All experiments were performed on a 1.5 T clinical MR system (Magnetom SP 4000; Siemens AG, Erlangen, Germany) with constant imaging parameters. Contrast-to-noise ratios (CNRs) of tubes doped with iron oxides at different concentrations and brain areas with physiological iron deposition (red nucleus, substantia nigra) were calculated for CSE and FSE pulse sequences. Areas of old brain hemorrhage were analyzed for lesion conspicuity by blinded analysis with CSE as an internal standard. CNR of iron oxide tubes (TE 90 ins, CSE 45.0 {+-} 3.5, FSE 16 echo trains 28.5 {+-} 3. 1; p {le} 0.01) and iron-containing brain areas decreased with increasing echo trains of FSE sequences. A significantly lower number of old hemorrhagic brain lesions was visible in patients scanned with FSE sequences (6 echo trains: n = 28; 16 echo trains: n = 26) than CSE (n = 40). Our results demonstrate that the sensitivity of RARE-derived techniques to susceptibility effects is significantly decreased compared with CSE. CSE sequences or GE sequences should still be preferred in patients with a history of seizures or intracranial hemorrhage. 25 refs., 3 figs., 1 tabs.

  8. Tumor Imaging and Targeting Potential of an Hsp70-Derived 14-Mer Peptide

    PubMed Central

    Oellinger, Rupert; Breuninger, Stephanie; Rad, Roland; Pockley, Alan G.; Multhoff, Gabriele

    2014-01-01

    Background We have previously used a unique mouse monoclonal antibody cmHsp70.1 to demonstrate the selective presence of a membrane-bound form of Hsp70 (memHsp70) on a variety of leukemia cells and on single cell suspensions derived from solid tumors of different entities, but not on non-transformed cells or cells from corresponding ’healthy‘ tissue. This antibody can be used to image tumors in vivo and target them for antibody-dependent cellular cytotoxicity. Tumor-specific expression of memHsp70 therefore has the potential to be exploited for theranostic purposes. Given the advantages of peptides as imaging and targeting agents, this study assessed whether a 14-mer tumor penetrating peptide (TPP; TKDNNLLGRFELSG), the sequence of which is derived from the oligomerization domain of Hsp70 which is expressed on the cell surface of tumor cells, can also be used for targeting membrane Hsp70 positive (memHsp70+) tumor cells, in vitro. Methodology/Principal Findings The specificity of carboxy-fluorescein (CF-) labeled TPP (TPP) to Hsp70 was proven in an Hsp70 knockout mammary tumor cell system. TPP specifically binds to different memHsp70+ mouse and human tumor cell lines and is rapidly taken up via endosomes. Two to four-fold higher levels of CF-labeled TPP were detected in MCF7 (82% memHsp70+) and MDA-MB-231 (75% memHsp70+) cells compared to T47D cells (29% memHsp70+) that exhibit a lower Hsp70 membrane positivity. After 90 min incubation, TPP co-localized with mitochondrial membranes in memHsp70+ tumors. Although there was no evidence that any given vesicle population was specifically localized, fluorophore-labeled cmHsp70.1 antibody and TPP preferentially accumulated in the proximity of the adherent surface of cultured cells. These findings suggest a potential association between membrane Hsp70 expression and cytoskeletal elements that are involved in adherence, the establishment of intercellular synapses and/or membrane reorganization. Conclusions/Significance This study demonstrates the specific binding and rapid internalization of TPP by tumor cells with a memHsp70+ phenotype. TPP might therefore have potential for targeting and imaging the large proportion of tumors (?50%) that express memHsp70. PMID:25165986

  9. Use of anatomical knowledge to register 3-D blood vessel data derived from DSA with MR images

    NASA Astrophysics Data System (ADS)

    Hill, Derek L.; Hawkes, David J.; Hardingham, Charles R.

    1991-06-01

    We propose a new algorithm for registering 3D reconstructions of blood vessels from DSA with MR images of the brain. The registration transformation is determined by fitting the blood vessel tree reconstructed from DSA projections into the fissures of the brain derived from MR images, somewhat in the manner of fitting a key into a lock. The fit of the vessels into the fissures is guided by specific but simple anatomical knowledge. Preliminary evaluation of the algorithm has been carried out using data derived from a cadaver brain.

  10. Enhancing proprioceptive input to motoneurons differentially affects expression of neurotrophin 3 and brain-derived neurotrophic factor in rat hoffmann-reflex circuitry.

    PubMed

    Gajewska-Wo?niak, Olga; Skup, Ma?gorzata; Kasicki, Stefan; Ziemli?ska, Ewelina; Czarkowska-Bauch, Julita

    2013-01-01

    The importance of neurotrophin 3 (NT-3) for motor control prompted us to ask the question whether direct electrical stimulation of low-threshold muscle afferents, strengthening the proprioceptive signaling, could effectively increase the endogenous pool of this neurotrophin and its receptor TrkC in the Hoffmann-reflex (H-reflex) circuitry. The effects were compared with those of brain-derived neurotrophic factor (BDNF) and its TrkB receptor. Continuous bursts of stimuli were delivered unilaterally for seven days, 80 min daily, by means of a cuff-electrode implanted over the tibial nerve in awake rats. The H-reflex was recorded in the soleus muscle to control the strength of stimulation. Stimulation aimed at activation of Ia fibers produced a strong increase of NT-3 protein, measured with ELISA, in the lumbar L3-6 segments of the spinal cord and in the soleus muscle. This stimulation exerted much weaker effect on BDNF protein level which slightly increased only in L3-6 segments of the spinal cord. Increased protein level of NT-3 and BDNF corresponded to the changes of NT-3 mRNA and BDNF mRNA expression in L3-6 segments but not in the soleus muscle. We disclosed tissue-specificity of TrkC mRNA and TrkB mRNA responses. In the spinal cord TrkC and TrkB transcripts tended to decrease, whereas in the soleus muscle TrkB mRNA decreased and TrkC mRNA expression strongly increased, suggesting that stimulation of Ia fibers leads to sensitization of the soleus muscle to NT-3 signaling. The possibility of increasing NT-3/TrkC signaling in the neuromuscular system, with minor effects on BDNF/TrkB signaling, by means of low-threshold electrical stimulation of peripheral nerves, which in humans might be applied in non-invasive way, offers an attractive therapeutic tool. PMID:23776573

  11. Exploration of peptide T7 and its derivative as integrin ?v?3-targeted imaging agents

    PubMed Central

    He, Xin; Hao, Yumei; Long, Wei; Song, Naling; Fan, Saijun; Meng, Aimin

    2015-01-01

    Objective The aim of the present study was to develop potential candidates of integrin ?v?3-targeted imaging agent, which can facilitate the diagnosis and treatment of malignant solid tumors. Methods Peptides derived from tumstatin, named T7 and T7-6H, were derivatized to contain histidine in the C-terminus of their sequence and were labeled with 99mTc via nitrido and carbonyl precursors. The radiochemical purity and stability of 99mTc-labeled T7 and T7-6H were characterized by thin-layer chromatography. The whole body biodistribution was studied in NCI-H157-bearing BALB/c nude mice. Results The 99mTc-labeled T7 and T7-6H showed adequate in vitro stability, with a high radiochemical purity of over 90%. The dissociation constant (Kd) value of the 99mTc-labeled T7 and T7-6H ranged from 68.5 nM to 140.8 nM in U251 and NCI-H157 cell lines. 99mTc-labeled T7 and T7-6H showed no significant difference of biodistribution in mice. Furthermore, both T7 and T7-6H exhibited a poor blood–brain barrier penetration and a transient accumulation in lung; the uptake in tumor tissues was significantly higher than in muscle tissue, with a ratio of 5.8. Conclusion 99mTc-labeled T7 and T7-6H can be regarded as promising single-photon emission computed tomography probes for imaging integrin ?v?3, and need to be further studied for noninvasive detection of tumors.

  12. Synthesis of [18F]-labelled Maltose Derivatives as PET Tracers for Imaging Bacterial Infection

    PubMed Central

    Namavari, Mohammad; Gowrishankar, Gayatri; Hoehne, Aileen; Jouannot, Erwan; Gambhir, Sanjiv S

    2015-01-01

    Purpose To develop novel positron emission tomography (PET) agents for visualization and therapy monitoring of bacterial infections. Procedures It is known that maltose and maltodextrins are energy sources for bacteria. Hence, 18F-labelled maltose derivatives could be a valuable tool for imaging bacterial infections. We have developed methods to synthesize 4-O-(?-D-glucopyranosyl)-6-deoxy-6-[18F]fluoro-D-glucopyranoside (6-[18F]fluoromaltose) and 4-O-(?-D-glucopyranosyl)-1-deoxy-1-[18F]fluoro-D-glucopyranoside (1-[18F]fluoromaltose) as bacterial infection PET imaging agents. 6-[18F]fluoromaltose was prepared from precursor 1,2,3-tri-O-acetyl-4-O-(2?,3?,-di-O-acetyl-4?,6?-benzylidene-?-D-glucopyranosyl)-6-deoxy-6-nosyl-D-glucopranoside (5). The synthesis involved the radio-fluorination of 5 followed by acidic and basic hydrolysis to give 6-[18F]fluoromaltose. In an analogous procedure, 1-[18F]fluoromaltose was synthesized from 2,3, 6-tri-O-acetyl-4-O-(2?,3?,4?,6-tetra-O-acetyl-?-D-glucopyranosyl)-1-deoxy-1-O-triflyl-D-glucopranoside (9). Stability of 6-[18F]fluoromaltose in phosphate-buffered saline (PBS) and human and mouse serum at 37 °C was determined. Escherichia coli uptake of 6-[18F]fluoromaltose was examined. Results A reliable synthesis of 1- and 6-[18F]fluoromaltose has been accomplished with 4–6 and 5–8 % radiochemical yields, respectively (decay-corrected with 95 % radiochemical purity). 6-[18F]fluoromaltose was sufficiently stable over the time span needed for PET studies (~96 % intact compound after 1-h and ~65 % after 2-h incubation in serum). Bacterial uptake experiments indicated that E. coli transports 6-[18F]fluoromaltose. Competition assays showed that the uptake of 6-[18F]fluoromaltose was completely blocked by co-incubation with 1 mM of the natural substrate maltose. Conclusion We have successfully synthesized 1- and 6-[18F]fluoromaltose via direct fluorination of appropriate protected maltose precursors. Bacterial uptake experiments in E. coli and stability studies suggest a possible application of 6-[18F]fluoromaltose as a new PET imaging agent for visualization and monitoring of bacterial infections. PMID:25277604

  13. Reliability of MRI-derived cortical and subcortical morphometric measures: Effects of pulse sequence, voxel geometry, and parallel imaging

    Microsoft Academic Search

    J. S. Wonderlick; D. A. Ziegler; P. Hosseini-Varnamkhasti; J. J. Locascio; A. Bakkour; A. van der Kouwe; C. Triantafyllou; S. Corkin; B. C. Dickerson

    2009-01-01

    Advances in magnetic resonance imaging (MRI) have contributed greatly to the study of neurodegenerative processes, psychiatric disorders, and normal human development, but the effect of such improvements on the reliability of downstream morphometric measures has not been extensively studied. We examined how MRI-derived neurostructural measures are affected by three technological advancements: parallel acceleration, increased spatial resolution, and the use of

  14. Synthesis and bio-evaluation of a new fatty acid derivative for myocardial imaging.

    PubMed

    Mathur, Anupam; Subramanian, Suresh; Mallia, Madhava B; Banerjee, Sharmila; Samuel, Grace; Sarma, Haladhar D; Venkatesh, Meera

    2008-09-01

    Development of a (99m)Tc-fatty acid analogue is of interest, as (99m)Tc is logistically advantageous over the cyclotron-produced (11)C and (123)I. Synthesis of a 16 carbon fatty acid derivative and its radiolabeling with the novel [(99m)TcN(PNP)](2+) core is described here. Hexadecanedioic acid was conjugated to cysteine in an overall yield of 55%. This ligand could be labeled with (99m)Tc via the [(99m)TcN(PNP)](2+) core, in 80% yield, as a mixture of two isomers (syn and anti). The major isomer isolated by HPLC was used for bioevaluation studies in swiss mice and compared with radioiodinated iodophenyl pentadecanoic acid (IPPA), an established agent for myocardial metabolic imaging. (99m)Tc-labeled complex cleared faster from the non-target organs, namely, liver, lungs, and blood compared to that of [(125)I]-IPPA. However, the complex exhibited lower uptake and faster washout from the myocardium as compared to [(125)I]-IPPA. PMID:18701306

  15. An operational software tool for the analysis of coronagraph images: Determining CME parameters for input into the WSA-Enlil heliospheric model

    NASA Astrophysics Data System (ADS)

    Millward, G.; Biesecker, D.; Pizzo, V.; Koning, C. A.

    2013-02-01

    Coronal mass ejections (CMEs)—massive explosions of dense plasma that originate in the lower solar atmosphere and propagate outward into the solar wind—are the leading cause of significant space weather effects within Earth's environment. Computational models of the heliosphere such as WSA-Enlil offer the possibility of predicting whether a given CME will become geo-effective and, if so, the likely time of arrival at Earth. To be meaningful, such a forecast model is dependent upon accurately characterizing key parameters for the CME, notably its speed and direction of propagation, and its angular width. Studies by Zhao et al. (2002) and Xie et al. (2004) suggest that these key CME parameters can be deduced from geometric analysis of the elliptical "halo" forms observed in coronagraph images on spacecraft such as the Solar and Heliospheric Observatory (SOHO) and which result from a CME whose propagation is roughly toward or away from the observer. Both studies assume that the CME presents a circular cross-section and maintains a constant angular width during its radial expansion, the so called "cone model." Development work at the NOAA Space Weather Prediction Center (SWPC) has been concerned with building and testing software tools to allow forecasters to determine these CME parameters routinely within an operational context, a key aspect of transitioning the WSA-Enlil heliospheric model into operations at the National Weather Service. We find "single viewpoint" cone analysis, while a useful start, to be highly problematic in many real-world situations. In particular, it is extremely difficult to establish objectively the correct ellipse that should be applied to a given halo form and that small changes in the exact ellipse chosen can lead to large differences in the deduced CME parameters. The inaccuracies in the technique are particularly evident for analysis of the "nearly circular" elliptical forms which result from CMEs that are propagating directly toward the observer and are therefore the most likely to be geo-effective. In working to resolve this issue we have developed a new three-dimensional (3-D) graphics-based analysis system which seeks to reduce inaccuracies by analyzing a CME using coronagraph images taken concurrently by SOHO and also by the two Solar TErrestrial RElations Observatory (STEREO) spacecraft, which provide additional viewing locations well away from the Sun-Earth line. The resulting "three view" technique has led to the development of the CME Analysis Tool (CAT), an operational software system in routine use at the SWPC as the primary means to determine CME parameters for input into the WSA-Enlil model. Results from the operational WSA-Enlil system are presented: utilizing CAT to provide CME input parameters, we show that, during the first year of operations at SWPC, the WSA-Enlil model has forecasted the arrival of CMEs at Earth with an average error 7.5 h.

  16. Synthesis, Radiolabeling and Biological Evaluation of 99mTc-labeled Deoxyglucose Derivatives for Molecular Imaging

    PubMed Central

    Sadeghzadeh, Masoud; Charkhlooiea, Ghorbanali; Johari Daha, Fariba

    2013-01-01

    Two deoxyglucose (DG) derivatives, (?,?)-2-deoxy-2-amino(ethylcarbamate)-D-glucose (ECB-DG) and (?,?)-2-deoxy-2-amino(1,2-dihydroxypropyl)-D-glucose (DHP-DG), were synthesized and radiolabeled successfully with [99mTc(H2O)3(CO)3]+ complex. [99mTc]-ECB-DG and [99mTc]-DHP-DG complexes were prepared (96% and 93% radiochemical purities respectively) by using 46 mCi of Na99mTcO4 in 1 mL saline. Radio-HPLC analysis of [99mTc]- ECB-DG at pH = 7.4, revealed that labeling with 99mTc leads to formation of one radiochemical species with tR = 381 second. Three radiochemical species, Na99mTcO4, [99mTc]-DHP-DG and [99mTc(H2O)3(CO)3]+ complexes with tR = 342 sec, tR = 567 sec and tR = 1586 sec respectively, were obtained when [99mTc]-DHP-DG complex evaluated by HPLC. Biodistribution of two complexes were studied on normal mice at 10, 30 and 60 min post-injections. Compared to the 18F-FDG, [99mTc]-ECB-DG displayed a 2.8-fold reduction in brain uptake (1.7 ± 0.2 versus 0.61% ± 0.09) ,whereas [99mTc]-DHP-DG just showed 1.9-fold reduction in heart uptake (2.2 ± 0.05 towards 1.16±0.10) at 1 h post-injection. On the basis of our results, it seems that ECB-DG and DHP-DG analogues could be used as brain and heart imaging agent respectively. PMID:24250633

  17. Glacier topography and elevation changes derived from Pléiades sub-meter stereo images

    NASA Astrophysics Data System (ADS)

    Berthier, E.; Vincent, C.; Magnússon, E.; Gunnlaugsson, Á. Þ.; Pitte, P.; Le Meur, E.; Masiokas, M.; Ruiz, L.; Pálsson, F.; Belart, J. M. C.; Wagnon, P.

    2014-12-01

    In response to climate change, most glaciers are losing mass and hence contribute to sea-level rise. Repeated and accurate mapping of their surface topography is required to estimate their mass balance and to extrapolate/calibrate sparse field glaciological measurements. In this study we evaluate the potential of sub-meter stereo imagery from the recently launched Pléiades satellites to derive digital elevation models (DEMs) of glaciers and their elevation changes. Our five evaluation sites, where nearly simultaneous field measurements were collected, are located in Iceland, the European Alps, the central Andes, Nepal and Antarctica. For Iceland, the Pléiades DEM is also compared to a lidar DEM. The vertical biases of the Pléiades DEMs are less than 1 m if ground control points (GCPs) are used, but reach up to 7 m without GCPs. Even without GCPs, vertical biases can be reduced to a few decimetres by horizontal and vertical co-registration of the DEMs to reference altimetric data on ice-free terrain. Around these biases, the vertical precision of the Pléiades DEMs is ±1 m and even ±0.5 m on the flat glacier tongues (1? confidence level). Similar precision levels are obtained in the accumulation areas of glaciers and in Antarctica. We also demonstrate the high potential of Pléiades DEMs for measuring seasonal, annual and multi-annual elevation changes with an accuracy of 1 m or better if cloud-free images are available. The negative region-wide mass balances of glaciers in the Mont-Blanc area (-1.04 ± 0.23 m a-1 water equivalent, w.e.) are revealed by differencing Satellite pour l'Observation de la Terre 5 (SPOT 5) and Pléiades DEMs acquired in August 2003 and 2012, confirming the accelerated glacial wastage in the European Alps.

  18. Improved High Resolution Controlled Enceladus Atlas derived from Cassini-ISS Images

    NASA Astrophysics Data System (ADS)

    Roatsch, T.; Kersten, E.; Hoffmeister, A.; Matz, K.-D.; Preusker, F.; Porco, C. C.

    2012-09-01

    The Cassini Imaging Science Subsystem (ISS) acquired 684 high-resolution images (< 1 km/pixel) of Enceladus during its tour through the Saturnian system since 2004. We have combined these images with lower-resolution Cassini images to produce a new high-resolution global controlled mosaic of this moonf Enceladus. This global mosaic is the baseline for the highresolution Enceladus atlas that consists of 15 tiles mapped at a scale of 1:500,000. The nomenclature used in this atlas was proposed by the Cassini imaging team and was approved by the International Astronomical Union (IAU). The whole atlas is available to the public through the Imaging Team's website [http://ciclops.org/maps].

  19. Average coherence image derived observations over an urban area: the case of Athens city

    Microsoft Academic Search

    I. Parcharidis; M. Foumelis; P. Kourkouli

    2007-01-01

    In the present study coherence observations, in relation to the land-cover type, obtained using 20 C-band ERS SAR Single Look Complex (SLC) VV-polarization images acquired in descending mode over the metropolitan area of Athens covering the period 1992-1999 are presented. A straightforward approach using a single master SAR image on which the other images are mapped was adopted ensuring perfect

  20. Comparison of Satellite-Derived Vegetation Indices Generated from MODIS and LANDSAT 7 ETM+ Data IMAGE RESOLUTION EFFECTS FOR VEGETATION MAPPING FROM

    E-print Network

    Poggi, Davide

    IMAGE RESOLUTION EFFECTS FOR VEGETATION MAPPING FROM LANDSAT 7 ETM+ AND TERRA MODIS DATA Piero BOCCARDO resolution vegetation mapping for hydrological purposes, a comparative study of NDVI images derived from synthetic parameters and investigating their dependency on the geometric resolution of the images

  1. Deriving star-formation and extinction in normal galaxies from H(alpha) and Paschen(beta) imaging

    NASA Astrophysics Data System (ADS)

    Malhotra, Sangeeta; Dale, Daniel; Rhoads, James; Helou, George; Kennicutt, Robert; Hunter, Deidre

    1999-08-01

    We propose to derive spatial maps of extinction corrected ionizing radiation and dust columns using narrow-band imaging in H(alpha) and Paschen(beta) of normal, nearby galaxies. This is possible because the intrinsic line ratios are insensitive to temperature and densities in HII regions. Comparison of observed line ratios to the intrinsic ones, using the extinction law, will yield column densities of dust near the HII regions. Using extinction corrected ionizing radiation and dust column maps we will derive the expected dust emission maps and compare them to the observed mid-infrared dust emission maps to determine how much heating of the dust is due to ionizing radiation. We will compare the extinction-corrected H(alpha) emission with other tracers of star- formation, far-infrared continuum and the main cooling lines of the interstellar gas [CII] (158 (mu)m) and [OI] (63 (mu)m). Corrected H(alpha) will also be used to estimate fraction of the [CII] (158 (mu)m) from ionized gas. This is necessary so we can compare the [CII] line fluxes to models of neutral photodissociation regions (PDRs) to derive mass, density, and pressure of the gas. The radiation densities derived for PDRs can also be compared the radiation column densities derived from corrected H(alpha) maps. All the data from ISO has been reduced and calibrated. We request time to do H(alpha) imaging of southern 1/4 of our sample and Pa(beta) imaging of a subset of galaxies.

  2. Identification and detection of oil and oil-derived substances at the surface and subsurface levels via hyperspectral imaging

    NASA Astrophysics Data System (ADS)

    Alam, M. S.; Gollapalli, R. P.; Sidike, P.

    2012-04-01

    Detection and estimation of oil and oil-derived substances from an oil spill is a challenging issue. Over the last few years, several algorithms have been proposed for the detection of oil on the ocean surface. These techniques do not address the issue of detection of subsurface oil and estimate the depth of the location of oil at the subsurface level. In this paper, algorithms are developed to detect the presence of surface oil in ocean water using hyperspectral imagery. A support vector machine classifier was trained using region-of-interests (ROIs) to classify the oil/oil-derived substances under the water surface in the Gulf of Mexico. Using the pixel intensity of the identified oil based image, Beer-Lambert's law is used to calculate the depth at which the oil and/or oil-derived substance are present in the scene of investigation.

  3. Recent rapid thinning of the ``Mer de Glace'' glacier derived from satellite optical images

    Microsoft Academic Search

    E. Berthier; Y. Arnaud; D. Baratoux; C. Vincent; F. Rémy

    2004-01-01

    The rapid wastage of mountain glaciers and their contribution to sea level rise require worldwide monitoring of their mass balance. In this paper, we show that changes in glacier thickness can be accurately measured from satellite images. We use SPOT image pairs to build Digital Elevation Models (DEMs) of the Mont Blanc area (French Alps) for different years. To register

  4. Red fluorescent luminogen from pyrrole derivatives with aggregation-enhanced emission for cell membrane imaging.

    PubMed

    Liu, Guogang; Chen, Didi; Kong, Lingwei; Shi, Jianbing; Tong, Bin; Zhi, Junge; Feng, Xiao; Dong, Yuping

    2015-05-01

    A dye emitted red fluorescence with aggregation-enhanced emission properties was reported here. It can be utilized to specifically recognize the cell membrane of MCF-7 and 293T cell lines during bio-imaging. PMID:25896404

  5. Geometric algebra colour image representations and derived total orderings for morphological operators Part I: Colour quaternions

    E-print Network

    Angulo,Jesús

    operators ­ Part I: Colour quaternions Jesús Angulo * CMM ­ Centre de Morphologie Mathématique mathematical morphology Colour quaternion Quaternion total ordering Nonlinear colour filtering Colour feature extraction Colour image representation Hypercomplex representation Colour potential function Quaternion

  6. Direct imaging of biological sulfur dioxide derivatives in vivo using a two-photon phosphorescent probe.

    PubMed

    Li, Guanying; Chen, Yu; Wang, Jinquan; Wu, Jingheng; Gasser, Gilles; Ji, Liangnian; Chao, Hui

    2015-09-01

    Sulfur dioxide (SO2) and its derivatives sulfite and bisulfite play important roles in biological systems. However, in vivo detection of sulfite/bisulfite remains challenging. In this study, we developed a dinuclear Ir(III) complex (Ir4) as a two-photon phosphorescent probe for sulfite and bisulfite. Ir4 selectively and rapidly responded, with high sensitivity, to sulfite/bisulfite over other bio-related ions and molecules. One-photon and two-photon microscopy images revealed that Ir4 preferentially targeted mitochondria and was capable of imaging biological sulfite/bisulfite levels in vitro and in vivo. In situ sulfite generation in Caenorhabditis elegans was visualized by two-photon excitation real-time imaging. Finally, Ir4 was employed to monitor sulfite distribution in rat brain and other tissues. This study is the first report of the direct visualization of SO2 derivatives in vivo. These results provide new insights into the biological importance of SO2. PMID:26100342

  7. Automatic Input Rectification

    E-print Network

    Long, Fan

    2011-10-03

    We present a novel technique, automatic input rectification, and a prototype implementation called SOAP. SOAP learns a set of constraints characterizing typical inputs that an application is highly likely to process ...

  8. Automatic input rectification

    E-print Network

    Long, Fan

    We present a novel technique, automatic input rectification, and a prototype implementation, SOAP. SOAP learns a set of constraints characterizing typical inputs that an application is highly likely to process correctly. ...

  9. Automatic input rectification

    E-print Network

    Long, Fan, S.M. Massachusetts Institute of Technology

    2012-01-01

    We present a novel technique, automatic input rectification, and a prototype implementation, SOAP. SOAP learns a set of constraints characterizing typical inputs that an application is highly likely to process correctly. ...

  10. Incorporating User Input in Template-Based Segmentation

    PubMed Central

    Vidal, Camille; Beggs, Dale; Younes, Laurent; Jain, Sanjay K.; Jedynak, Bruno

    2015-01-01

    We present a simple and elegant method to incorporate user input in a template-based segmentation method for diseased organs. The user provides a partial segmentation of the organ of interest, which is used to guide the template towards its target. The user also highlights some elements of the background that should be excluded from the final segmentation. We derive by likelihood maximization a registration algorithm from a simple statistical image model in which the user labels are modeled as Bernoulli random variables. The resulting registration algorithm minimizes the sum of square differences between the binary template and the user labels, while preventing the template from shrinking, and penalizing for the inclusion of background elements into the final segmentation. We assess the performance of the proposed algorithm on synthetic images in which the amount of user annotation is controlled. We demonstrate our algorithm on the segmentation of the lungs of Mycobacterium tuberculosis infected mice from ?CT images.

  11. High-resolution CCD imaging and derived gravitational lens models of 2237+0305

    NASA Technical Reports Server (NTRS)

    Schneider, D. P.; Turner, E. L.; Gunn, J. E.; Hewitt, J. N.; Schmidt, M.

    1988-01-01

    Images of the gravitational lens 2237+0305 acquired in good seeing have resolved the system into at least five components within the central few arsec of the object: the galaxy nucleus and four point sources in a ringlike formation approximately centered on the galaxy. It is found that the four point sources are distinctly bluer than the galaxy, but that they do not have identical colors. The observed configuration is well reproduced by a simple model that assumes that the four objects are images of the quasar and that the lens is a constant mass-to-light ratio, elliptical, de Vaucouleurs bulge.

  12. On the camparability of cloud fractions derived from whole sky imager and ceilometer data

    SciTech Connect

    Rodriguez, D.

    1998-01-30

    The Atmospheric Radiation Measurement (ARM) Program`s most heavily instrumented site is its central facility in Lamont, OK. With respect to cloud observations, the instrumentation included a whole sky imager, ceilometers, lidar, millimeter cloud radar, microwave profilers, and radiosondes. Data from three of these instrument--the Whole Sky Imager (WSI), Belfort Laser Ceilometer (BLC) and Micropulse Lidar (MPL)-- are used in this study primarily to investigate the utility of using ceilometers, now strategically emplaced at four additional locations along the perimeter of the site.

  13. Effect of injection technique on temporal parametric imaging derived from digital subtraction angiography in patient specific phantoms

    NASA Astrophysics Data System (ADS)

    Ionita, Ciprian N.; Garcia, Victor L.; Bednarek, Daniel R.; Snyder, Kenneth V.; Siddiqui, Adnan H.; Levy, Elad I.; Rudin, Stephen

    2014-03-01

    Parametric imaging maps (PIM's) derived from digital subtraction angiography (DSA) for the cerebral arterial flow assessment in clinical settings have been proposed, but experiments have yet to determine the reliability of such studies. For this study, we have observed the effects of different injection techniques on PIM's. A flow circuit set to physiologic conditions was created using an internal carotid artery phantom. PIM's were derived for two catheter positions, two different contrast bolus injection volumes (5ml and 10 ml), and four injection rates (5, 10, 15 and 20 ml/s). Using a gamma variate fitting approach, we derived PIM's for mean-transit-time (MTT), time-to-peak (TTP) and bolus-arrivaltime (BAT). For the same injection rates, a larger bolus resulted in an increased MTT and TTP, while a faster injection rate resulted in a shorter MTT, TTP, and BAT. In addition, the position of the catheter tip within the vasculature directly affected the PIM. The experiment showed that the PIM is strongly correlated with the injection conditions, and, therefore, they have to be interpreted with caution. PIM images must be taken from the same patient to be able to be meaningfully compared. These comparisons can include pre- and post-treatment images taken immediately before and after an interventional procedure or simultaneous arterial flow comparisons through the left and right cerebral hemispheres. Due to the strong correlation between PIM and injection conditions, this study indicates that this assessment method should be used only to compare flow changes before and after treatment within the same patient using the same injection conditions.

  14. DERIVATION OF THE MAGNETIC FIELD IN A CORONAL MASS EJECTION CORE VIA MULTI-FREQUENCY RADIO IMAGING

    SciTech Connect

    Tun, Samuel D. [The Naval Research Laboratory, Washington, DC 20375 (United States)] [The Naval Research Laboratory, Washington, DC 20375 (United States); Vourlidas, A. [Space Science Division, Naval Research Laboratory, Washington, DC 20375 (United States)] [Space Science Division, Naval Research Laboratory, Washington, DC 20375 (United States)

    2013-04-01

    The magnetic field within the core of a coronal mass ejection (CME) on 2010 August 14 is derived from analysis of multi-wavelength radio imaging data. This CME's core was found to be the source of a moving type IV radio burst, whose emission is here determined to arise from the gyrosynchrotron process. The CME core's true trajectory, electron density, and line-of-sight depth are derived from stereoscopic observations, constraining these parameters in the radio emission models. We find that the CME carries a substantial amount of mildly relativistic electrons (E < 100 keV) in a strong magnetic field (B < 15 G), and that the spectra at lower heights are preferentially suppressed at lower frequencies through absorption from thermal electrons. We discuss the results in light of previous moving type IV burst studies, and outline a plan for the eventual use of radio methods for CME magnetic field diagnostics.

  15. Effects of quantum noise in 4D-CT on deformable image registration and derived ventilation data

    NASA Astrophysics Data System (ADS)

    Latifi, Kujtim; Huang, Tzung-Chi; Feygelman, Vladimir; Budzevich, Mikalai M.; Moros, Eduardo G.; Dilling, Thomas J.; Stevens, Craig W.; van Elmpt, Wouter; Dekker, Andre; Zhang, Geoffrey G.

    2013-11-01

    Quantum noise is common in CT images and is a persistent problem in accurate ventilation imaging using 4D-CT and deformable image registration (DIR). This study focuses on the effects of noise in 4D-CT on DIR and thereby derived ventilation data. A total of six sets of 4D-CT data with landmarks delineated in different phases, called point-validated pixel-based breathing thorax models (POPI), were used in this study. The DIR algorithms, including diffeomorphic morphons (DM), diffeomorphic demons (DD), optical flow and B-spline, were used to register the inspiration phase to the expiration phase. The DIR deformation matrices (DIRDM) were used to map the landmarks. Target registration errors (TRE) were calculated as the distance errors between the delineated and the mapped landmarks. Noise of Gaussian distribution with different standard deviations (SD), from 0 to 200 Hounsfield Units (HU) in amplitude, was added to the POPI models to simulate different levels of quantum noise. Ventilation data were calculated using the ?V algorithm which calculates the volume change geometrically based on the DIRDM. The ventilation images with different added noise levels were compared using Dice similarity coefficient (DSC). The root mean square (RMS) values of the landmark TRE over the six POPI models for the four DIR algorithms were stable when the noise level was low (SD <150 HU) and increased with added noise when the level is higher. The most accurate DIR was DD with a mean RMS of 1.5 ± 0.5 mm with no added noise and 1.8 ± 0.5 mm with noise (SD = 200 HU). The DSC values between the ventilation images with and without added noise decreased with the noise level, even when the noise level was relatively low. The DIR algorithm most robust with respect to noise was DM, with mean DSC = 0.89 ± 0.01 and 0.66 ± 0.02 for the top 50% ventilation volumes, as compared between 0 added noise and SD = 30 and 200 HU, respectively. Although the landmark TRE were stable with low noise, the differences between ventilation images increased with noise level, even when the noise was low, indicating ventilation imaging from 4D-CT was sensitive to image noise. Therefore, high quality 4D-CT is essential for accurate ventilation images.

  16. Evaluation of a 125I-labelled benzazepinone derived voltage-gated sodium channel blocker for imaging with SPECT.

    PubMed

    Pérez-Medina, Carlos; Patel, Niral; Robson, Mathew; Badar, Adam; Lythgoe, Mark F; Årstad, Erik

    2012-12-21

    Voltage-gated sodium channels (VGSCs) are a family of transmembrane proteins that mediate fast neurotransmission, and are integral to sustain physiological conditions and higher cognitive functions. Imaging of VGSCs in vivo holds promise as a tool to elucidate operational functions in the brain and to aid the treatment of a wide range of neurological diseases. To assess the suitability of 1-benzazepin-2-one derived VGSC blockers for imaging, we have prepared a (125)I-labelled analogue of BNZA and evaluated the tracer in vivo. In an automated patch-clamp assay, a diastereomeric mixture of the non-radioactive compound blocked the Na(v)1.2 and Na(v)1.7 VGSC isoforms with IC(50) values of 4.1 ± 1.5 ?M and 0.25 ± 0.07 ?M, respectively. [(3)H]BTX displacement studies revealed a three-fold difference in affinity between the two diastereomers. Iodo-destannylation of a tin precursor with iodine-125 afforded the two diastereomerically pure tracers, which were used to assess binding to VGSCs in vivo by comparing their tissue distributions in mice. Whilst the results point to a lack of VGSC binding in vivo, SPECT imaging revealed highly localized uptake in the interscapular region, an area typically associated with brown adipose tissue, which in addition to high metabolic stability of the iodinated tracer, demonstrate the potential of 1-benzazepin-2-ones for in vivo imaging. PMID:23117159

  17. Derivation of new emission factors for quantification of mass emissions when using optical gas imaging for detecting leaks.

    PubMed

    Lev-On, Miriam; Epperson, David; Siegell, Jeffrey; Ritter, Karin

    2007-09-01

    This paper describes the development of new "leak/no-leak" emission factors that are suitable for estimating facilities' fugitive emissions when using an alternative work practice (AWP) that is based on optical gas imaging technology for detecting leaking piping system components. These emission factors were derived for valves, pumps, and connectors/flanges for instrument leak detection thresholds ranging from 3 to 60 g/hr using a combination of field data and Monte Carlo statistical simulation techniques. These newly derived leak/no-leak emission factors are designed to replace the U.S. Environment Protection Agency (EPA) 1995 Protocol factors, which were based on Method 21 monitoring of leaks at "uncontrolled" facilities. The emission factors published in the 1995 Protocol have not been updated since the 1970s. This derivation is based on results where the authors document the use of a Monte Carlo simulation technique to quantify the required leak detection thresholds that provide equal--or better--environmental benefits for an AWP. The use of these newly derived emission factors is demonstrated for different methods of computing fugitive emissions from a hypothetical model refinery. The resulting facility emissions calculated by using these new emission factors is compared with the existing emission estimation methods provided in the EPA 1995 Protocol. The results demonstrate that the new emission factors provide an emission estimate that is the closest to that obtained from the direct determination of total emissions by Monte Carlo simulations. PMID:17912925

  18. Optical and electronic characterization of sol-gel- derived silica aerogels for display and imaging applications

    Microsoft Academic Search

    Sally Ann Cahill

    1999-01-01

    Aerogels are a unique class of ultra low-density solid materials with interconnected pores and porosities up to 98%. Their nanometer-sized structures create remarkable optical, electrical, and structural properties. This dissertation focuses on the optical and electronic properties of silica aerogels foruse in display and imaging applications. Thus the absorption and emission bands of aerogels, the aerogel's response to free electrons,

  19. The age of reason for FDG PET image derived indices Dimitris Visvikis1

    E-print Network

    Paris-Sud XI, Université de

    Tixier1 , Catherine Cheze-le Rest2 1 INSERM, UMR1101LaTIM, Brest, France 2 Department of Nuclear Medicine Author manuscript, published in "European Journal of Nuclear Medicine and Molecular Imaging 2012;:xx" DOI with the accuracy of SUVmeandetermination include the precision and robustness in the delineation of the tumour

  20. Analysis of parametric images derived from genomic sequences using neural network based approaches

    Microsoft Academic Search

    Alain GIRON; Joseph VILAIN; Camille SERRUYS; Djamel BRAHMI; Patrick DESCHAVANNE; Bernard FERTIL

    1999-01-01

    The exploration of DNA genomic huge sequences (up to several megabases) needs new kind of data representation allowing robust analyses. With the help of the chaos game representation method (CGR), fractal images can be generated, which allow to observe, at a glance, frequencies of words (small sequences of the four bases: G, A, T, C) in DNA sequences. Classification of

  1. High-resolution CCD imaging and derived gravitational lens models of 2237+0305

    Microsoft Academic Search

    D. P. Schneider; E. L. Turner; J. E. Gunn; J. N. Hewitt; M. Schmidt; C. R. Lawrence

    1988-01-01

    Images of the gravitational lens 2237+0305 acquired in good seeing have resolved the system into at least five components within the central few arsec of the object: the galaxy nucleus and four point sources in a ringlike formation approximately centered on the galaxy. It is found that the four point sources are distinctly bluer than the galaxy, but that they

  2. Quality and compatibility analyses of global aerosol products derived from the advanced very high resolution radiometer and Moderate Resolution Imaging Spectroradiometer

    Microsoft Academic Search

    Myeong-Jae Jeong; Zhanqing Li; D. Allen Chu; Si-Chee Tsay

    2005-01-01

    There exist numerous global aerosol products derived from various satellite sensors, but little insight has been gained about their compatibility and quality. This study presents a comparison of two prominent global aerosol products derived over oceans from the advanced very high resolution radiometer (AVHRR) under the Global Aerosol Climatology Project (GACP) (Mishchenko et al., 1999) and the Moderate Resolution Imaging

  3. Crustal evolution derived from the Izu-Bonin-Mariana arc velocity images

    Microsoft Academic Search

    N. Takahashi; S. Kodaira; Y. Tatsumi; S. Miura; T. Sato; M. Yamashita; T. No; T. Takahashi; N. Noguchi; K. Takizawa; Y. Kaiho; Y. Kaneda

    2010-01-01

    The Izu-Bonin-Mariana arc is known as one of typical oceanic island arcs, which has developed by subduction between oceanic crusts producing continental materials. Japan Agency for Marine-Earth Science and Technology has carried out seismic surveys using a multi-channel reflection survey system (MCS) and ocean bottom seismographs (OBSs) in the Izu-Bonin-Mariana (IBM) arc since 2002, and reported these crustal images. As

  4. Partial dependence of breast tumor malignancy on ultrasound image features derived from boosted trees

    NASA Astrophysics Data System (ADS)

    Yang, Wei; Zhang, Su; Li, Wenying; Chen, Yaqing; Lu, Hongtao; Chen, Wufan; Chen, Yazhu

    2010-04-01

    Various computerized features extracted from breast ultrasound images are useful in assessing the malignancy of breast tumors. However, the underlying relationship between the computerized features and tumor malignancy may not be linear in nature. We use the decision tree ensemble trained by the cost-sensitive boosting algorithm to approximate the target function for malignancy assessment and to reflect this relationship qualitatively. Partial dependence plots are employed to explore and visualize the effect of features on the output of the decision tree ensemble. In the experiments, 31 image features are extracted to quantify the sonographic characteristics of breast tumors. Patient age is used as an external feature because of its high clinical importance. The area under the receiver-operating characteristic curve of the tree ensembles can reach 0.95 with sensitivity of 0.95 (61/64) at the associated specificity 0.74 (77/104). The partial dependence plots of the four most important features are demonstrated to show the influence of the features on malignancy, and they are in accord with the empirical observations. The results can provide visual and qualitative references on the computerized image features for physicians, and can be useful for enhancing the interpretability of computer-aided diagnosis systems for breast ultrasound.

  5. Processing distributed inputs in coupled excitable lasers

    SciTech Connect

    Gonzalez, Cristina M.; Torrent, M. C.; Garcia-Ojalvo, Jordi [Departament de Fisica i Enginyeria Nuclear, Universitat Politecnica de Catalunya, Colom 11, E-08222 Terrassa (Spain); Buldu, Javier M. [Nonlinear Dynamics and Chaos Group, Departamento de Fisica, Universidad Rey Juan Carlos, Tulipan s/n, 28933 Mostoles, Madrid (Spain)

    2007-11-15

    In many instances, networks of dynamical elements are subject to distributed input signals that enter the network through different nodes. In these cases, processing of the input signals may be mediated by coupling, in what constitutes an emerging property of the network. Here we study experimentally this effect in two mutually injected semiconductor lasers with optical feedback, operating in an excitable regime. The lasers are subject to different periodic input signals in their pump current, with distinct frequencies. Our results show that when the signals are harmonics of an absent fundamental, the laser array is able to process these signals and respond at the missing fundamental frequency. When the input frequencies are rigidly shifted from their harmonic values, the response frequency follows a simple law derived from a linear sum of the inputs, even though the array integrates the electrical inputs after having transduced them optically. The results are reproduced numerically with a dynamical model of the laser array.

  6. Seismic Velocities Imaging around "AFA" Hydrothermal Area in West Java, Indonesia derived from Dense Seimometer Network

    NASA Astrophysics Data System (ADS)

    Fanani Akbar, Akhmad; Nugraha, Andri Dian; Jousset, Philippe GM; Ryannugroho, Riskiray; Gassner, Alexandra; Jaya, Makky S.; Sule, Rachmat; Diningrat, Wahyuddin; Hendryana, Andri; Kusnadi, Yosep; Umar, Muksin; Indrinanto, Yudi; Erbas, Kemal

    2015-04-01

    We have deployed about 48 three component seismometers around "AFA" hydrothermal are in West Java, Indonesia from October 2012 up to October 2014 in order to detect microseismic event and to enhance our knowledge about subsurface seismic stucture. The seismometer network in this study, is the first dense seismometer array monitoring around hydrothermal area in Indonesia so far. We analyzed a huge waveform data set to distinguish microseismic, local and regional events. Then, we picked the onset of P-and S-wave arrival of microseismic events carefully visually by eye. We determined the initial microseismic event by applying Geiger's method with uniform seismic velocity model. Totally, we have been successfully determined 2,497 microseismic events around this hydrothermal area. We also improved 1D seismic velocities (Vp, Vs) and simultaneously with hypocenter adjustment as input for the tomography inversion in this study. Overall, the microseismic events are concentrated around production area activities and we also found strong cluster microseismic event in Southern part of this region which still need to be investigated in more details. Now, we are going on tomographic inversion step by using double-difference method. We are going to show more information during the meeting.

  7. Effect of chirality on cellular uptake, imaging and photodynamic therapy of photosensitizers derived from chlorophyll-a.

    PubMed

    Srivatsan, Avinash; Pera, Paula; Joshi, Penny; Wang, Yanfang; Missert, Joseph R; Tracy, Erin C; Tabaczynski, Walter A; Yao, Rutao; Sajjad, Munawwar; Baumann, Heinz; Pandey, Ravindra K

    2015-07-01

    We have previously shown that the (124)I-analog of methyl 3-(1'-m-iodobenzyloxy) ethyl-3-devinyl-pyropheophorbide-a derived as racemic mixture from chlorophyll-a can be used for PET (positron emission tomography)-imaging in animal tumor models. On the other hand, as a non-radioactive analog, it showed excellent fluorescence and photodynamic therapy (PDT) efficacy. Thus, a single agent in a mixture of radioactive ((124)I-) and non-radioactive ((127)I) material can be used for both dual-imaging and PDT of cancer. Before advancing to Phase I human clinical trials, we evaluated the activity of the individual isomers as well as the impact of a chiral center at position-3(1) in directing in vitro/in vivo cellular uptake, intracellular localization, epithelial tumor cell-specific retention, fluorescence/PET imaging, and photosensitizing ability. The results indicate that both isomers (racemates), either as methyl ester or carboxylic acid, were equally effective. However, the methyl ester analogs, due to subcellular deposition into vesicular structures, were preferentially retained. All derivatives containing carboxylic acid at the position-17(2) were noted to be substrate for the ABCG2 (a member of the ATP binding cassette transporters) protein explaining their low retention in lung tumor cells expressing this transporter. The compounds in which the chirality at position-3 has been substituted by a non-chiral functionality showed reduced cellular uptake, retention and lower PDT efficacy in mice bearing murine Colon26 tumors. PMID:25936263

  8. Input devices for CCDs

    NASA Astrophysics Data System (ADS)

    Trishenkov, M. A.; Vinetskii, Iu. R.

    1982-12-01

    A systematic account of the physical and network-engineering aspects of the operation and design of input devices for CCDs is presented with emphasis on the maximum possibilities of such devices with respect to the injection of small signals into the CCD. A classification of input devices is given. It is shown that a unified approach to input devices as devices that are based on transistor structures makes it possible to identify the properties and limitations of all types of input devices for CCDs. Particular consideration is given to potentials and charges of MOS cells, methods of signal injection, the concentration of charge carriers in the source and gate, and the volt-ampere characteristics of input devices. Equivalent circuits, modes of operation, and electric circuits of input devices are also considered

  9. In vivo imaging of VMAT2 in pancreas using a 18F epoxide derivative of tetrabenazine

    PubMed Central

    Kung, Hank F.; Lieberman, Brian P.; Zhuang, Zhi-Ping; Oya, Shunichi; Kung, Mei-Ping; Choi, Seok Rye; Poessl, Karl; Blankemeyer, Eric; Hou, Catherine; Skovronsky, Daniel; Kilbourn, Michael

    2008-01-01

    Objectives Development of imaging agents for pancreatic beta cell mass may provide tools for studying insulin-secreting beta cells and their relationship with diabetes mellitus. In this paper a new imaging agent, [18F](+)-2-oxiranyl-3-isobutyl-9-(3-fluoropropoxy)-10-methoxy-2,3,4,6,7,11b-hexahydro-1H-pyrido[2,1-a]isoquinoline [18F](+)4, which displays properties targeting vesicular monoamine transporter 2 (VMAT2) binding sites of beta cells in the pancreas, was evaluated as a PET (positron emission tomography) agent for estimating beta cell mass in vivo. The hydrolyzable epoxide group of (+)4 may provide a mechanism for shifting biodistribution from liver to kidney thus, reducing the background signal. Methods Both 18F and 19F labeled (+) and (?) isomers of 4 were synthesized and evaluated. Organ distribution was carried out in normal rats. Uptake of [18F](+)4 in pancreas of normal rats was measured and correlated with blocking studies using competing drugs, (+)dihydrotetrabenazine, (+)-DTBZ or 9-fluoropropyl-(+)dihydro tetrabenazine (FP-(+)-DTBZ, (+)2). Results In vitro binding study of VMAT2 using rat brain striatum showed a Ki value of 0.08 and 0.15 nM for the (+)4 and (±)4, respectively. The in vivo biodistribution of [18F](+)4 in rats showed the highest uptake in the pancreas (2.68 %ID/g at 60 min post-injection). In vivo competition experiments with cold FP-(+)-DTBZ, (+)2, (3.5 mg/kg, 5 min iv pretreatment) led to a significant reduction of pancreas uptake (85 % blockade at 60 min). The inactive isomer [18F](?)4 showed significantly lower pancreas uptake (0.22 %ID/g at 30 min post-injection). Animal PET imaging studies of [18F](+)4 in normal rats demonstrated an avid pancreatic uptake in rats. Conclusion The preliminary results suggest that the epoxide, [18F](+)4, is highly selective in binding to VMAT2 and it has an excellent uptake in the pancreas of rats. The liver uptake was significantly reduced through the use of the epoxide group. Therefore, it may be potentially useful for imaging beta cell mass in the pancreas. PMID:19026944

  10. Input-Output Analysis

    Microsoft Academic Search

    Ronald E. Miller; Peter D. Blair

    This 2009 edition of Ronald Miller and Peter Blair's classic textbook is an essential reference for students and scholars in the input-output research and applications community. The book has been fully revised and updated to reflect important developments in the field since its original publication. New topics covered include SAMs (and extended input-output models) and their connection to input-output data,

  11. Generation of bone marrow derived murine dendritic cells for use in 2-photon imaging.

    PubMed

    Matheu, Melanie P; Sen, Debasish; Cahalan, Michael D; Parker, Ian

    2008-01-01

    Several methods for the preparation of murine dendritic cells can be found in the literature. Here, we present a method that produces greater than 85% CD11c high dendritic cells in culture that home to the draining lymph node after subcutaneous injection and present antigen to antigen specific T cells (see video). Additionally, we use Essen Instruments Incucyte to track dendritic cell maturation, where, at day 10, the morphology of the cultured cells is typical of a mature dendritic cell and <85% of cells are CD11chigh. The study of antigen presentation in peripheral lymph nodes by 2-photon imaging revealed that there are three distinct phases of dendritic cell and T cell interaction. Phase I consists of brief serial contacts between highly motile antigen specific T cells and antigen carrying dendritic cells. Phase two is marked by prolonged contacts between antigen-specific T cell and antigen bearing dendritic cells. Finally, phase III is characterized by T cells detaching from dendritic cells, regaining motility and beginning to divide. This is one example of the type of antigen-specific interactions that can be analyzed by two-photon imaging of antigen-loaded cell tracker dye-labeled dendritic cells. PMID:19066518

  12. Potential for downscaling soil moisture maps derived from spaceborne imaging radar data

    NASA Astrophysics Data System (ADS)

    Crow, Wade T.; Wood, Eric F.; Dubayah, Ralph

    2000-01-01

    The presence of nonlinear relationships between surface soil moisture and various hydrologic processes suggests that grid-scale water and energy fluxes cannot be accurately modeled without subgrid-scale soil moisture information. For land surface and energy balance models run over continental- to global-scale domains, accurate fine-scale soil moisture observations are nearly impossible to obtain on a consistent basis and will likely remain so through the next generation of soil moisture remote sensors. In the absence of such data sets, an alternative approach is to generalize the statistical behavior of soil moisture fields across the relevant range of spatial scales. Downscaling procedures offer the possibility that the fine-scale statistical properties of soil moisture fields can be inferred from coarse-scale data. Such an approach was used for a 29×200 km transect of 25 m active radar data acquired over Oklahoma by NASA's spaceborne imaging radar imaging (SIR-C) mission on April 12, 1994. Using a soil dielectric inversion model, the radar data were processed to provide estimates of surface soil dielectric values, which can be equated to volumetric soil moisture content. The soil moisture field along each strip was analyzed for evidence of spatial scaling for scales ranging from 100 to 6400 m. Results suggest that a spatial scaling assumption may not always be an appropriate basis for a downscaling approach. Prospects for the development of a more robust downscaling procedure for soil moisture are discussed.

  13. Nitrogen-doped carbon dots derived from polyvinyl pyrrolidone and their multicolor cell imaging

    NASA Astrophysics Data System (ADS)

    Ding, Hui; Zhang, Peng; Wang, Tian-Yi; Kong, Ji-Lie; Xiong, Huan-Ming

    2014-05-01

    Nitrogen-doped carbon dots (N-CDs) with a high quantum yield of 19.6% were prepared by calcining polyvinyl pyrrolidone (PVP, K-30), and then modified with 4,7,10-trioxa-1,13-tridecanediamine. The as-prepared N-CDs exhibited excitation-dependent and pH-sensitive photoluminescence. Transmission electron microscopy and Raman spectra demonstrated the graphitic structure of the N-CDs. Fourier transform infrared spectroscopy and x-ray diffraction studies revealed successful passivation and the presence of hydrophilic groups on the surface. Importantly, such modified quantum dots acted as good multicolor cell imaging probes due to their excellent fluorescent properties, low cytotoxicity and fine dispersity.

  14. Building Credible Input Models

    Microsoft Academic Search

    Lawrence M. Leemis

    2004-01-01

    Most discrete-event simulation models have stochastic el- ements that mimic the probabilistic nature of the system under consideration. A close match between the input model and the true underlying probabilistic mechanism associated with the system is required for successful input modeling. The general question considered here is how to model an element (e.g., arrival process, service times) in a discrete-

  15. Modeling input processes

    SciTech Connect

    Iman, R.L.

    1986-01-01

    Computer models for various applications are closely scrutinized both from the standpoint of questioning the correctness of the underlying mathematical model with respect to the process it is attempting to model, and from the standpoint of verifying that the computer model correctly implements the underlying mathematical model. A process that receives less scrutiny, but is nonetheless of equal importance, concerns the individual and joint modeling of the inputs. This modeling effort clearly has a great impact on the credibility of results obtained from simulation studies. Model characteristics are reviewed that have a direct bearing on the model input process and reasons are given for using probabilistic based modeling with the inputs. Discussions are presented on how to model distributions for individual inputs and how to model multivariate input structures when dependence and other constraints may be present. 12 refs.

  16. Deriving Atmospheric Properties and Escape Rates from MAVEN's Imaging UV Spectrograph (IUVS)

    NASA Astrophysics Data System (ADS)

    Schneider, Nicholas M.; IUVS Science Team

    2013-10-01

    MAVEN (Mars Volatile and Atmosphere EvolutioN) is a Mars Scout mission being readied for launch in November 2013. The key hardware and management partners are University of Colorado, Goddard Space Flight Center, University of California at Berkeley, Lockheed Martin, and the Jet Propulsion Laboratory. MAVEN carries a powerful suite of fields and particles instruments and a sophisticated remote sensing instrument, the Imaging UltraViolet Spectrograph (IUVS). This presentation begins by describing IUVS' science goals, instrument design, operational approach and data analysis strategy. IUVS supports the top-level MAVEN science goals: measure the present state of the atmosphere, observe its response to varying solar stimuli, and use the information to estimate loss from Mars' atmosphere over time. The instrument operates at low spectral resolution spanning the FUV and MUV ranges in separate channels, and at high resolution around the hydrogen Lyman alpha line to measure the D/H ratio in the upper atmosphere. MAVEN carries the instrument on an Articulated Payload Platform which orients the instrument for optimal observations during four segments of its 4.5 hr elliptical orbit. During periapse passage, IUVS uses a scan mirror to obtain vertical profiles of emissions from the atmosphere and ionosphere. Around apoapse, the instrument builds up low-resolution images of the atmosphere at multiple wavelengths. In between, the instrument measures emissions from oxygen, hydrogen and deuterium in the corona. IUVS also undertakes day-long stellar occultation campaigns at 2 month intervals, to measure the state of the atmosphere at altitudes below the airglow layer and in situ sampling. All data will be pipeline-processed from line brightnesses to column abundances, local densities and global 3-D maps. The focus of the presentation is development of these automatic processing algorithms and the data products they will provide to the Mars community through the PDS Atmospheres Node. The combined results from all instruments on ion and neutral escape will bear on the central question of the history of Mars' atmosphere and climate history. This work has been supported by NASA's MAVEN mission.

  17. Tailoring inputs to achieve maximal neuronal firing

    PubMed Central

    2011-01-01

    We consider the constrained optimization of excitatory synaptic input patterns to maximize spike generation in leaky integrate-and-fire (LIF) and theta model neurons. In the case of discrete input kicks with a fixed total magnitude, optimal input timings and strengths are identified for each model using phase plane arguments. In both cases, optimal features relate to finding an input level at which the drop in input between successive spikes is minimized. A bounded minimizing level always exists in the theta model and may or may not exist in the LIF model, depending on parameter tuning. We also provide analytical formulas to estimate the number of spikes resulting from a given input train. In a second case of continuous inputs of fixed total magnitude, we analyze the tuning of an input shape parameter to maximize the number of spikes occurring in a fixed time interval. Results are obtained using numerical solution of a variational boundary value problem that we derive, as well as analysis, for the theta model and using a combination of simulation and analysis for the LIF model. In particular, consistent with the discrete case, the number of spikes in the theta model rises and then falls again as the input becomes more tightly peaked. Under a similar variation in the LIF case, we numerically show that the number of spikes increases monotonically up to some bound and we analytically constrain the times at which spikes can occur and estimate the bound on the number of spikes fired. PMID:22656323

  18. Visualization of Membrane Rafts Using a Perylene Monoimide Derivative and Fluorescence Lifetime Imaging

    PubMed Central

    Margineanu, Anca; Hotta, Jun-ichi; Van der Auweraer, Mark; Ameloot, Marcel; Stefan, Alina; Beljonne, David; Engelborghs, Yves; Herrmann, Andreas; Müllen, Klaus; De Schryver, Frans C.; Hofkens, Johan

    2007-01-01

    A new membrane probe, based on the perylene imide chromophore, with excellent photophysical properties (high absorption coefficient, quantum yield (QY) ? 1, high photostability) and excited in the visible domain is proposed for the study of membrane rafts. Visualization of separation between the liquid-ordered (Lo) and the liquid-disordered (Ld) phases can be achieved in artificial membranes by fluorescence lifetime imaging due to the different decay times of the membrane probe in the two phases. Rafts on micrometer-scale in cell membranes due to cellular activation can also be observed by this method. The decay time of the dye in the Lo phase is higher than in organic solvents where its QY is 1. This allows proposing a (possible general) mechanism for the decay time increase in the Lo phase, based on the local field effects of the surrounding molecules. For other fluorophores with QY < 1, the suggested mechanism could also contribute, in addition to effects reducing the nonradiative decay pathways, to an increase of the fluorescence decay time in the Lo phase. PMID:17573424

  19. Diurnal, Seasonal, and Interannual Variations of Cloud Properties Derived for CERES From Imager Data

    NASA Technical Reports Server (NTRS)

    Minnis, Patrick; Young, David F.; Sun-Mack, Sunny; Trepte, Qing Z.; Chen, Yan; Brown, Richard R.; Gibson, Sharon; Heck, Patrick W.

    2004-01-01

    Simultaneous measurement of the radiation and cloud fields on a global basis is a key component in the effort to understand and model the interaction between clouds and radiation at the top of the atmosphere, at the surface, and within the atmosphere. The NASA Clouds and Earth s Radiant Energy System (CERES) Project, begun in 1998, is meeting this need. Broadband shortwave (SW) and longwave radiance measurements taken by the CERES scanners at resolutions between 10 and 20 km on the Tropical Rainfall Measuring Mission (TRMM), Terra, and Aqua satellites are matched to simultaneous retrievals of cloud height, phase, particle size, water path, and optical depth OD from the TRMM Visible Infrared Scanner (VIRS) and the Moderate Resolution Imaging Spectroradiometer (MODIS) on Terra and Aqua. Besides aiding the interpretation of the broadband radiances, the CERES cloud properties are valuable for understanding cloud variations at a variety of scales. In this paper, the resulting CERES cloud data taken to date are averaged at several temporal scales to examine the temporal and spatial variability of the cloud properties on a global scale at a 1 resolution.

  20. Monitoring tropical-cyclone intensity using environmental wind fields derived from short-interval satellite images

    NASA Technical Reports Server (NTRS)

    Rodgers, E.; Gentry, R. C.

    1983-01-01

    The feasibility of predicting changes in tropical storm intensity based on satellite observations of the dynamical relationships between the large-scale upper and lower tropospheric circulations surrounding the cyclone and the characteristics of the storm's inner core is studied. Rapid-scan visible images from the SMS-1 and GOES-1 satellites were used to examine the local change in relative angular momentum (RAM), the lower and upper tropospheric environmental areal mean relative vorticity and transverse circulation on three consecutive days for tropical storms Caroline (August, 1975), Anita (August and September, 1977) and Ella (September, 1978). The three case studies suggest that storm intensification may be predicted from the storm's local change of net RAM, with this quantity best correlated with storm intensification after a time lag of 6 hours. Intensification is also found to be related to the environmental lower and upper tropospheric areal-mean relative vorticity, and to the upper tropospheric environmental circulation, which acts either to hinder or to enhance the storm's anticyclonic outflow channels.

  1. The July urban heat island of Bucharest as derived from modis images

    NASA Astrophysics Data System (ADS)

    Cheval, S.; Dumitrescu, A.

    2009-04-01

    The urban heat island (UHI) of the city of Bucharest (Romania) is analyzed in terms of its extension, geometry, and magnitude using the surface thermal data provided by the moderate resolution imaging spectroradiometer (MODIS) sensors. An objective method is developed that allows to delineate the UHI. The study focuses on the months of July from the 2000-2006 time interval. The average surface temperatures obtained for each pixel (1 km resolution) were analyzed on cross-profiles that helped us to determine the outline of the UHI. The shifting points identified by the Rodionov test in the temperature series of each profile were considered as possible limits of the UHI. Seemingly, the land cover has a major influence on the extension and the geometry of the Bucharest UHI in July. The magnitude of the heat island was calculated by comparing the average temperature inside its limits and the average temperature of the 5 km (a) and of the 10 km (b) buffers around it. The thermal difference between the UHI and the surrounding area of Bucharest is higher and more variable during the daytime, and is noticeably related to the land cover.

  2. Integration of Image Data for Refining Building Boundaries Derived from Point Clouds

    NASA Astrophysics Data System (ADS)

    Perera, S. N.; Hetti Arachchige, N.; Schneider, D.

    2014-08-01

    Geometrically and topologically correct 3D building models are required to satisfy with new demands such as 3D cadastre, map updating, and decision making. More attention on building reconstruction has been paid using Airborne Laser Scanning (ALS) point cloud data. The planimetric accuracy of roof outlines, including step-edges is questionable in building models derived from only point clouds. This paper presents a new approach for the detection of accurate building boundaries by merging point clouds acquired by ALS and aerial photographs. It comprises two major parts: reconstruction of initial roof models from point clouds only, and refinement of their boundaries. A shortest closed circle (graph) analysis method is employed to generate building models in the first step. Having the advantages of high reliability, this method provides reconstruction without prior knowledge of primitive building types even when complex height jumps and various types of building roof are available. The accurate position of boundaries of the initial models is determined by the integration of the edges extracted from aerial photographs. In this process, scene constraints defined based on the initial roof models are introduced as the initial roof models are representing explicit unambiguous geometries about the scene. Experiments were conducted using the ISPRS benchmark test data. Based on test results, we show that the proposed approach can reconstruct 3D building models with higher geometrical (planimetry and vertical) and topological accuracy.

  3. An Analysis of Whole Body Tracer Kinetics in Dynamic PET Studies With Application to Image-Based Blood Input Function Extraction

    PubMed Central

    Huang, Jian; O’Sullivan, Finbarr

    2014-01-01

    In a positron emission tomography (PET) study, the local uptake of the tracer is dependent on vascular delivery and retention. For dynamic studies the measured uptake time-course information can be best interpreted when knowledge of the time-course of tracer in the blood is available. This is certainly true for the most established tracers such as 18F-Fluorodeoxyglucose (FDG) and 15O-Water (H2O). Since direct sampling of blood as part of PET studies is increasingly impractical, there is ongoing interest in image-extraction of blood time-course information. But analysis of PET-measured blood pool signals is complicated because they will typically involve a combination of arterial, venous and tissue information. Thus, a careful appreciation of these components is needed to interpret the available data. To facilitate this process, we propose a novel Markov chain model for representation of the circulation of a tracer atom in the body. The model represents both arterial and venous time-course patterns. Under reasonable conditions equilibration of tracer activity in arterial and venous blood is achieved by the end of the PET study—consistent with empirical measurement. Statistical inference for Markov model parameters is a challenge. A penalized nonlinear least squares process, incorporating a generalized cross-validation score, is proposed. Random effects analysis is used to adaptively specify the structure of the penalty function based on historical samples of directly measured blood data. A collection of arterially sampled data from PET studies with FDG and H2O is used to illustrate the methodology. These data analyses are highly supportive of the overall modeling approach. An adaptation of the model to the problem of extraction of arterial blood signals from imaging data is also developed and promising preliminary results for cerebral and thoracic imaging studies with FDG and H2O are obtained. PMID:24770914

  4. Congestion control through input rate regulation

    Microsoft Academic Search

    Moshe Sidi; Wen-zu Liu; Israel Cidon; Inder Gopal

    1989-01-01

    Input-rate-regulation schemes are extensively studied from the viewpoint of smoothing and regulating effects of the incoming traffic. The smoothing effect is characterized by the variance of the interdeparture time of the packet-departure process from the input-rate-regulation mechanism. Under the assumption of Poisson arrivals, the characteristics of this departure process are explicitly derived in terms of the scheme's parameters, and the

  5. Horizontal winds derived from the polar mesospheric cloud images as observed by the CIPS instrument on the AIM satellite

    NASA Astrophysics Data System (ADS)

    Rong, P. P.; Yue, J.; Russell, J. M.; Lumpe, J. D.; Gong, J.; Wu, D. L.; Randall, C. E.

    2015-06-01

    A cloud pattern matching technique is applied to polar mesospheric cloud (PMC) images taken by the Cloud Imaging and Particle Size instrument (CIPS) to infer the wind velocities in the mesopause region. CIPS measurements are analyzed to detect patterns that repeat from one orbit to the next but are displaced in location; the displacement provides a measure of the wind velocity. Pattern matching is achieved by resampling the CIPS data to longitude and latitude grids with the grid-box size forced at ~5 km in both directions. The correlated patterns are searched within a geographic region referred to as a "frame" of ~500 km in longitude × 400 km in latitude. The histograms of the derived velocities indicate that easterly winds prevail, with a mean zonal wind of -20 to -15 m/s. Mean meridional winds are overall small, but in late summer the histogram indicated a poleward wind of ~20-30 m/s. The variability of CIPS cloud albedo on consecutive orbits is also examined at fixed geolocations. The statistical results suggest that ~86% of pairs underwent mean cloud albedo variation of < 50% on consecutive orbits, suggesting a moderate change. It is also found that the correlation of the cloud structures between two consecutive orbits at a fixed location is generally poor. These findings suggest that cloud patterns are subject to wind advection, but the cloud patches are more extended in size than the movement that occurs. Cloud voids are found to be more likely to remain at the same geolocations.

  6. PET image reconstruction with a system matrix containing point spread function derived from single photon incidence response

    NASA Astrophysics Data System (ADS)

    Fan, Xin; Wang, Hai-Peng; Yun, Ming-Kai; Sun, Xiao-Li; Cao, Xue-Xiang; Liu, Shuang-Quan; Chai, Pei; Li, Dao-Wu; Liu, Bao-Dong; Wang, Lu; Wei, Long

    2015-01-01

    A point spread function (PSF) for the blurring component in positron emission tomography (PET) is studied. The PSF matrix is derived from the single photon incidence response function. A statistical iterative reconstruction (IR) method based on the system matrix containing the PSF is developed. More specifically, the gamma photon incidence upon a crystal array is simulated by Monte Carlo (MC) simulation, and then the single photon incidence response functions are calculated. Subsequently, the single photon incidence response functions are used to compute the coincidence blurring factor according to the physical process of PET coincidence detection. Through weighting the ordinary system matrix response by the coincidence blurring factors, the IR system matrix containing the PSF is finally established. By using this system matrix, the image is reconstructed by an ordered subset expectation maximization (OSEM) algorithm. The experimental results show that the proposed system matrix can substantially improve the image radial resolution, contrast, and noise property. Furthermore, the simulated single gamma-ray incidence response function depends only on the crystal configuration, so the method could be extended to any PET scanner with the same detector crystal configuration. Project supported by the National Natural Science Foundation of China (Grant Nos. Y4811H805C and 81101175).

  7. Derivation of lowland riparian wetland deposit architecture using geophysical image analysis and interface detection

    NASA Astrophysics Data System (ADS)

    Chambers, J. E.; Wilkinson, P. B.; Uhlemann, S.; Sorensen, J. P. R.; Roberts, C.; Newell, A. J.; Ward, W. O. C.; Binley, A.; Williams, P. J.; Gooddy, D. C.; Old, G.; Bai, L.

    2014-07-01

    For groundwater-surface water interactions to be understood in complex wetland settings, the architecture of the underlying deposits requires investigation at a spatial resolution sufficient to characterize significant hydraulic pathways. Discrete intrusive sampling using conventional approaches provides insufficient sample density and can be difficult to deploy on soft ground. Here a noninvasive geophysical imaging approach combining three-dimensional electrical resistivity tomography (ERT) and the novel application of gradient and isosurface-based edge detectors is considered as a means of illuminating wetland deposit architecture. The performance of three edge detectors were compared and evaluated against ground truth data, using a lowland riparian wetland demonstration site. Isosurface-based methods correlated well with intrusive data and were useful for defining the geometries of key geological interfaces (i.e., peat/gravels and gravels/Chalk). The use of gradient detectors approach was unsuccessful, indicating that the assumption that the steepest resistivity gradient coincides with the associated geological interface can be incorrect. These findings are relevant to the application of this approach in settings with a broadly layered geology with strata of contrasting resistivities. In addition, ERT revealed substantial structures in the gravels related to the depositional environment (i.e., braided fluvial system) and a complex distribution of low-permeability putty Chalk at the bedrock surface—with implications for preferential flow and variable exchange between river and groundwater systems. These results demonstrate that a combined approach using ERT and edge detectors can provide valuable information to support targeted monitoring and inform hydrological modeling of wetlands.

  8. Algal Accessory Pigment Detection Using AVIRIS Image-Derived Spectral Radiance Data

    NASA Technical Reports Server (NTRS)

    Richardson, Laurie L.; Ambrosia, Vincent G.

    1996-01-01

    Visual and derivative analyses of AVIRIS spectral data can be used to detect algal accessory pigments in aquatic communities. This capability extends the use of remote sensing for the study of aquatic ecosystems by allowing detection of taxonomically significant pigment signatures which yield information about the type of algae present. Such information allows remote sensing-based assessment of aquatic ecosystem health, as in the detection of nuisance blooms of cyanobacteria or toxic blooms of dinoflagellates. Remote sensing of aquatic systems has traditionally focused on quantification of chlorophyll a, a photoreactive (and light-harvesting) pigment which is common to all algae as well as cyanobacteria (bluegreen algae). Due to the ubiquitousness of this pigment within algae, chl a is routinely measured to estimate algal biomass both during ground-truthing and using various airborne or satellite based sensors, including AVIRIS. Within the remote sensing and aquatic sciences communities, ongoing research has been performed to detect algal accessory pigments for assessment of algal population composition. This research is based on the fact that many algal accessory pigments are taxonomically significant, and all are spectrally unique. Aquatic scientists have been refining pigment analysis techniques, primarily high performance liquid chromatography, or HPLC, to detect specific pigments as a time-saving alternative to individual algal cell identifications and counts. Remote sensing scientists are investigating the use of pigment signatures to construct pigment libraries analogous to mineral spectral libraries used in geological remote sensing applications. The accessory pigment approach has been used successfully in remote sensing using data from the Thematic Mapper, low-altitude, multiple channel scanners, field spectroradiometers and the AVIRIS hyperspectral scanner. Due to spectral and spatial resolution capabilities, AVIRIS is the sensor of choice for such studies. We present here our results on detection of algal accessory pigments using AVIRIS data.

  9. Format( )MEDIC( )Input

    NASA Astrophysics Data System (ADS)

    Foster, K.

    1994-09-01

    This document is a description of a computer program called Format( )MEDIC( )Input. The purpose of this program is to allow the user to quickly reformat wind velocity data in the Model Evaluation Database (MEDb) into a reasonable 'first cut' set of MEDIC input files (MEDIC.nml, StnLoc.Met, and Observ.Met). The user is cautioned that these resulting input files must be reviewed for correctness and completeness. This program will not format MEDb data into a Problem Station Library or Problem Metdata File. A description of how the program reformats the data is provided, along with a description of the required and optional user input and a description of the resulting output files. A description of the MEDb is not provided here but can be found in the RAS Division Model Evaluation Database Description document.

  10. Edge detection in gated cardiac nuclear medicine images

    Microsoft Academic Search

    Cliff X. Wang; Lon Small; Wesley E. Snyder; Rodney Williams

    1994-01-01

    Mean field annealing using a piecewise linear model was applied to gated cardiac nuclear medicine images as a preprocessing tool for image smoothing and noise reduction. A second derivative operator was then used to extract the edges for ventricle boundary estimation. Combined with the user input initial boundary estimate, the extracted edge information was used to find a minimum cost

  11. Refined images of the crust around the SAFOD drill site derived from combined active and passive seismic experiment data

    NASA Astrophysics Data System (ADS)

    Roecker, S.; Thurber, C.; Shuler, A.; Liu, Y.; Zhang, H.; Powell, L.

    2005-12-01

    Five years of effort collecting and analyzing earthquake and explosion data in the vicinity of the SAFOD drill site culminated in the determination of the final trajectory for summer 2005's Phase 2 drilling. The trajectory was defined to optimize the chance of reaching one of two adjacent M2 "target earthquake" fault patches, whose centroids are separated horizontally by about 50 meters, with one or more satellite coreholes planned for Phase 3 drilling in summer 2007. Some of the most critical data for the final targeting were explosion data recorded on a Paulsson Geophysical Services, Inc., 80-element 3-component borehole string and earthquake data recorded on a pair of 3-component Duke University geophones in the SAFOD borehole. We are now utilizing the full 5-year dataset to refine our knowledge of three-dimensional (3D) crustal structure, wave propagation characteristics, and earthquake locations around SAFOD. These efforts are proceeding in parallel in several directions. Improved picks from a careful reanalysis of shear waves observed on the PASO array will be used in deriving an improved tomographic 3D wavespeed model. We are using finite-difference waveform modeling to investigate waveform complexity for earthquakes in and near the target region, including fault-zone head waves and strong secondary S-wave arrivals. A variety of waveform imaging methods are being applied to image fine-scale 3D structure and subsurface scatterers, including fault zones. In the process, we aim to integrate geophysical logging and geologic observations with our models to try to associate the target region earthquake activity, which is occurring on two fault strands about 280 meters apart, with shear zones encountered in the SAFOD Phase-2 borehole. These observations will be agumented and the target earthquake locations further refined over the next 2 years through downhole and surface recording of natural earthquakes and surface shots conducted at PASO station locations.

  12. Horizontal and vertical distribution of bromine monoxide in northern Alaska during BROMEX derived from airborne imaging-DOAS measurements

    NASA Astrophysics Data System (ADS)

    Pöhler, Denis; Stephan, General; Zielcke, Johannes; Shepson, Paul B.; Sihler, Holger; Stirm, Brian H.; Frieß, Udo; Pratt, Kerry A.; Walsh, Steve; Simpson, William R.; Platt, Ulrich

    2013-04-01

    Bromine monoxide (BrO) is a reactive halogen species (RHS) and has been known for quite a while to have a profound impact on the chemistry of the polar tropospheric boundary layer. Details of the bromine release and reaction processes are still unclear, especially the role of frost flowers, first-year sea ice, aerosols, atmospheric stability and snow. To investigate important details of the bromine release, a novel imaging DOAS instrument for the ultraviolet wavelength range (300 to 400 nm) was deployed aboard a light twin-engine aircraft (ALAR, Purdue Univ.) as part of the BRomine, Ozone, and Mercury EXperiment (BROMEX) in Barrow, Alaska, in spring 2012. This instrument utilizes (1) a scanner system in nadir direction to map trace gas distributions of the overflown area at high spatial resolution and (2) a forward-looking system, to observe the vertical trace gas distribution. Both viewing directions are equipped with digital cameras, enabling the creation of aerial maps and the comparison of spectral data with background features. We derived horizontal and vertical distribution of bromine monoxide (BrO) and other gases (e.g. NO2) over a wide variety of sea, ice and land surface conditions (first-year sea ice, frost flowers, open leads, and arctic tundra). We observed strong horizontal gradients of BrO within few km and a fast movement of BrO plumes. Distributions change significantly within few hours. The data show interesting correlations to the different surfaces. Additionally a clear anti-correlation of BrO and NO2 can be observed. Tropospheric BrO-distributions derived from satellite observations match within the satellite resolution those seen with the aircraft. Vertical gradients show a shallow layer of BrO close to the surface. These and other results from the 11 flights will be presented together with conclusions of the involved chemistry.

  13. Bioluminescent Imaging of Genetically Selected Induced Pluripotent Stem Cell-Derived Cardiomyocytes after Transplantation into Infarcted Heart of Syngeneic Recipients

    PubMed Central

    Lepperhof, Vera; Polchynski, Olga; Kruttwig, Klaus; Brüggemann, Chantal; Neef, Klaus; Drey, Florian; Zheng, Yunjie; Ackermann, Justus P.; Choi, Yeong-Hoon; Wunderlich, Thomas F.; Hoehn, Mathias; Hescheler, Jürgen; Šari?, Tomo

    2014-01-01

    Cell loss after transplantation is a major limitation for cell replacement approaches in regenerative medicine. To assess the survival kinetics of induced pluripotent stem cell (iPSC)-derived cardiomyocytes (CM) we generated transgenic murine iPSC lines which, in addition to CM-specific expression of puromycin N-acetyl-transferase and enhanced green fluorescent protein (EGFP), also constitutively express firefly luciferase (FLuc) for bioluminescence (BL) in vivo imaging. While undifferentiated iPSC lines generated by random integration of the transgene into the genome retained stable FLuc activity over many passages, the BL signal intensity was strongly decreased in purified iPS-CM compared to undifferentiated iPSC. Targeted integration of FLuc-expression cassette into the ROSA26 genomic locus using zinc finger nuclease (ZFN) technology strongly reduced transgene silencing in iPS-CM, leading to a several-fold higher BL compared to iPS-CM expressing FLuc from random genomic loci. To investigate the survival kinetics of iPS-CM in vivo, purified CM obtained from iPSC lines expressing FLuc from a random or the ROSA26 locus were transplanted into cryoinfarcted hearts of syngeneic mice. Engraftment of viable cells was monitored by BL imaging over 4 weeks. Transplanted iPS-CM were poorly retained in the myocardium independently of the cell line used. However, up to 8% of cells survived for 28 days at the site of injection, which was confirmed by immunohistological detection of EGFP-positive iPS-CM in the host tissue. Transplantation of iPS-CM did not affect the scar formation or capillary density in the periinfarct region of host myocardium. This report is the first to determine the survival kinetics of drug-selected iPS-CM in the infarcted heart using BL imaging and demonstrates that transgene silencing in the course of iPSC differentiation can be greatly reduced by employing genome editing technology. FLuc-expressing iPS-CM generated in this study will enable further studies to reduce their loss, increase long-term survival and functional integration upon transplantation. PMID:25226590

  14. Handling Input and Output for COAMPS

    NASA Technical Reports Server (NTRS)

    Fitzpatrick, Patrick; Tran, Nam; Li, Yongzuo; Anantharaj, Valentine

    2007-01-01

    Two suites of software have been developed to handle the input and output of the Coupled Ocean Atmosphere Prediction System (COAMPS), which is a regional atmospheric model developed by the Navy for simulating and predicting weather. Typically, the initial and boundary conditions for COAMPS are provided by a flat-file representation of the Navy s global model. Additional algorithms are needed for running the COAMPS software using global models. One of the present suites satisfies this need for running COAMPS using the Global Forecast System (GFS) model of the National Oceanic and Atmospheric Administration. The first step in running COAMPS downloading of GFS data from an Internet file-transfer-protocol (FTP) server computer of the National Centers for Environmental Prediction (NCEP) is performed by one of the programs (SSC-00273) in this suite. The GFS data, which are in gridded binary (GRIB) format, are then changed to a COAMPS-compatible format by another program in the suite (SSC-00278). Once a forecast is complete, still another program in the suite (SSC-00274) sends the output data to a different server computer. The second suite of software (SSC- 00275) addresses the need to ingest up-to-date land-use-and-land-cover (LULC) data into COAMPS for use in specifying typical climatological values of such surface parameters as albedo, aerodynamic roughness, and ground wetness. This suite includes (1) a program to process LULC data derived from observations by the Moderate Resolution Imaging Spectroradiometer (MODIS) instruments aboard NASA s Terra and Aqua satellites, (2) programs to derive new climatological parameters for the 17-land-use-category MODIS data; and (3) a modified version of a FORTRAN subroutine to be used by COAMPS. The MODIS data files are processed to reformat them into a compressed American Standard Code for Information Interchange (ASCII) format used by COAMPS for efficient processing.

  15. In vivo imaging of adipose-derived mesenchymal stem cells in female nude mice after simulated childbirth injury

    PubMed Central

    DAI, MIAO; XU, PEIRONG; HOU, MIN; TENG, YINCHENG; WU, QINGKAI

    2015-01-01

    The aim of the present study was to track in vivo the distribution and survival of adipose-derived mesenchymal stem cells (ASCs) transplanted into female BALB/c nude mice following simulated childbirth injury, using green fluorescent protein and luciferase dual labeling, bioluminescent imaging (BLI) and histological evaluation. The results demonstrated that the dually labeled ASCs could be detected for up to eight weeks in vivo. The number of implanted cells decreased during the first three weeks, and then stabilized until the end of the experiment. According to the linear regression plot, ~27,621 implanted cells survived until eight weeks after implantation. Transplanted ASCs predominantly existed at the inoculation site of the vagina, with little or no spread to other organs. Histological analysis confirmed the survival of the engrafted ASCs. The study provided basic evidence that BLI techniques can be used to monitor ASCs in vivo in real time and in the long term. Through local administration, ASCs could survive in the long term to facilitate repair following pelvic-floor injury. PMID:25574200

  16. Synthesis and evaluation of novel F-18 labeled fluoroarylvaline derivatives: potential PET imaging agents for tumor detection.

    PubMed

    Qiao, Yali; He, Yong; Zhang, Shuting; Li, Guixia; Liu, Hang; Xu, Jingli; Wang, Xiao; Qi, Chuanmin; Peng, Cheng

    2009-08-15

    Two F-18 labeled fluoroarylvaline derivatives, methyl 2-(2-[(18)F]fluoro-4-nitrobenzamido)-3-methylbutanoate ([(18)F]1, [(18)F]MFNBMB) and its corresponding acid 2-(2-[(18)F]fluoro-4-nitrobenzamido)-3-methylbutanoic acid ([(18)F]2, [(18)F]FNBMBA), have been designed and synthesized, respectively, by our team. Meanwhile, we research on their biodistributions in mice model bearing S 180 tumor. Furthermore, we also carried out the biological evaluations of 2-[(18)F]fluorodeoxyglucose ([(18)F]FDG) and O-2-[(18)F]fluoroethyl-l-tyrosine (l-[(18)F]FET) in the same model for comparison with our targeting molecules [(18)F]1 and [(18)F]2. Excitingly, the tumor/blood (T/Bl) and tumor/brain (T/Br) ratios were 2.91, 7.06 at 30 min, 3.44, 5.61 at 60 min post injection for [(18)F]1, 2.32, 13.30 for [(18)F]2 at 30 min post injection, which were obviously superior to [(18)F]FDG and l-[(18)F]FET in the same model and demonstrated that [(18)F]1 and [(18)F]2, especially [(18)F]2, were potential PET imaging agents for tumor detection. PMID:19616943

  17. Synthesis and evaluation of a 18F-labeled spirocyclic piperidine derivative as promising ?1 receptor imaging agent.

    PubMed

    Chen, Yuan-Yuan; Wang, Xia; Zhang, Jin-Ming; Deuther-Conrad, Winnie; Zhang, Xiao-Jun; Huang, Yiyun; Li, Yan; Ye, Jia-Jun; Cui, Meng-Chao; Steinbach, Jörg; Brust, Peter; Liu, Bo-Li; Jia, Hong-Mei

    2014-10-01

    Several spirocyclic piperidine derivatives were designed and synthesized as ?1 receptor ligands. In vitro competition binding assays showed that the fluoroalkoxy analogues with small substituents possessed high affinity towards ?1 receptors and subtype selectivity. Particularly for ligand 1'-((6-(2-fluoroethoxy)pyridin-3-yl)methyl)-3H-spiro[2-benzofuran-1,4'-piperidine] (2), high ?1 receptor affinity (Ki=2.30 nM) and high ?1/?2 subtype selectivity (142-fold) as well as high ?1/VAChT selectivity (234-fold) were observed. [18F]2 was synthesized using an efficient one-pot, two-step reaction method in a home-made automated synthesis module, with an overall isolated radiochemical yield of 8-10%, a radiochemical purity of higher than 99%, and specific activity of 56-78GBq/?mol. Biodistribution studies of [18F]2 in ICR mice indicated high initial brain uptake and a relatively fast washout. Administration of haloperidol, compound 1 and different concentrations of SA4503 (3, 5, or 10 ?mol/kg) 5 min prior to injection of [18F]2 significantly decreased the accumulation of radiotracer in organs known to contain ?1 receptors. Ex vivo autoradiography in Sprague-Dawley rats demonstrated high accumulation of radiotracer in brain areas with high expression of ?1 receptors. These encouraging results prove that [18F]2 is a suitable candidate for ?1 receptor imaging with PET in humans. PMID:25189691

  18. A post-processing technique for displaying vessels from routine fast-spin-echo images: MRI-derived angiography

    Microsoft Academic Search

    Yi-Hsuan Kao; Stefan S. Winkler; Eva H. Baker; Patrick A. Turski; Woei Chyn Chu

    1999-01-01

    Fast-spin-echo magnetic resonance (MR) images are routine components of a standard MR brain examination. On these images, blood vessels are visible as black flow void. We report that by applying an enhancement filter to a stack of routine fast-spin-echo MR images, projected angiographic images can be generated. The vascular detail in the projected image is similar to that observed in

  19. Honeybee navigation: odometry with monocular input

    Microsoft Academic Search

    M. V SRINIVASAN; S. W ZHANG; M LEHRER

    1998-01-01

    Recent studies have revealed that navigating honeybees,Apis mellifera, estimate the distance to a food source by integrating over time the image motion that they experience en route. Here we examine the ability of honeybees to gauge distance travelled when visual input is available primarily to one eye. Bees were trained to fly into a tunnel, lined with textured patterns, to

  20. Input/Output Trends.

    ERIC Educational Resources Information Center

    Mitchell, J.

    This paper discusses batch processing; and on-line, time-sharing operations, and their associate input/output equipment. Special emphasis is placed on electronic display equipment. It concludes that future equipment trends will allow the user more and easier access to the machine he uses. (Author)

  1. CISNET: Common Input Generators

    Cancer.gov

    For purposes of generating common parameters for the larger CISNET simulation models, a series of smaller, focused models was created in collaboration between the CISNET consortium members and NCI. These parameter generators are "mini models" in themselves in that they involve input data, processing guided by assumptions, and produce results.

  2. Yet another user input method: Accelerometer assisted single key input

    Microsoft Academic Search

    Chunming Gao; Robert Pastel; Jindong Tan

    2010-01-01

    In this paper we present YAUIM - yet another user input method. YAUIM is an alternative user input mechanism to the conventional keyboard, mouse, and touch screen inputs. It utilizes the embedded accelerometer to detect device movements and tilt positions to enable user inputs. Accelerometers embedded in devices have been used to identify meaningful combinations of movements for gaming and

  3. Temporal and Spatial Assessment of Yearly Solar Maps Derived from Satellite Images over the UAE and Qatar

    NASA Astrophysics Data System (ADS)

    Eissa, Y.; Marpu, P. R.; Ghedira, H.; Chiesa, M.

    2012-12-01

    The unique climate of countries located within the Arabian Peninsula, characterized by high dust concentrations, high humidity and modest cloud coverage, requires regional models to retrieve the solar irradiance components from satellite images. An artificial neural network (ANN) model has shown promising results in estimating the direct normal, diffuse horizontal and global horizontal irradiances using thermal satellite channels over the United Arab Emirates (UAE). This model is trained with six thermal channels of the SEVIRI instrument, onboard Meteosat Second Generation, along with the solar zenith angle, day number, solar time and eccentricity correction. The outputs of this model are the solar irradiance components at 15-min temporal and 3-km spatial resolutions, which are then utilized to derive the daily, monthly and yearly irradiation maps over the UAE and Qatar. The purpose of this research is to examine the temporal and spatial variations for annual irradiation maps over the UAE and Qatar, derived using the ANN approach. For the period ranging from 2008 to 2010, the year of 2009 shows the lowest annual direct normal and global horizontal irradiation, and the highest diffuse horizontal irradiation. That is due to frequent dust events which occurred during 2009. The annual direct normal irradiation maps for 2008 to 2010 show the same trend, with the higher irradiation values in the southern area of UAE and the values decreasing as the coast approaches in the northern region. For any given year, Qatar generally shows lower direct normal irradiation values than the UAE. This might be explained by higher humidity in Qatar due to its coastal climate. As for the annual diffuse horizontal irradiation maps, the lower irradiation values are observed in the southern area of UAE and along some coastal regions, with the higher values being in the middle. Qatar shows higher values in the western region, due to the increased airborne dust coming from Saudi Arabia, as opposed to the eastern coast which is along the Arabian Gulf. The annual global horizontal irradiation maps show less spatial variations. For the UAE the values consistently increase from north to south, while for Qatar lower values are observed along the eastern coast and the higher values are in the inland and southern locations. The direct normal irradiation map over the UAE and Qatar for the year 2010, which had values greater than 2008 and 2009.

  4. Photochemistryand Photobiology,2005, 81: 1499-1 504 Spectral Properties of Pro-multimodal Imaging Agents Derived

    E-print Network

    Larson-Prior, Linda

    Photochemistryand Photobiology,2005, 81: 1499-1 504 Spectral Properties of Pro-multimodal Imaging properties of cypate upon conjugation with DOTA and subsequent chelation with metals. The fluorescence imaging agents; MRI, magnetic resonance imaging; Mtt, 4-methyltrityl; NIR, near infrared; PET, positron

  5. NUPlans Budgeting Grant Input View

    E-print Network

    Shull, Kenneth R.

    NUPlans Budgeting Grant Input View FMS704 NUPlansGrantInputViewV2 Last updated 4/7/2014 - rb © 2014 Northwestern University FMS704 NUPlans Contributor Budgeting 1 of 5 NUPlans Grant Input View NUPlans enables schools and units with grant projects to input grant expense estimates per project for the next fiscal

  6. Stein's neuronal model with pooled renewal input.

    PubMed

    Rajdl, Kamil; Lansky, Petr

    2015-06-01

    The input of Stein's model of a single neuron is usually described by using a Poisson process, which is assumed to represent the behaviour of spikes pooled from a large number of presynaptic spike trains. However, such a description of the input is not always appropriate as the variability cannot be separated from the intensity. Therefore, we create and study Stein's model with a more general input, a sum of equilibrium renewal processes. The mean and variance of the membrane potential are derived for this model. Using these formulas and numerical simulations, the model is analyzed to study the influence of the input variability on the properties of the membrane potential and the output spike trains. The generalized Stein's model is compared with the original Stein's model with Poissonian input using the relative difference of variances of membrane potential at steady state and the integral square error of output interspike intervals. Both of the criteria show large differences between the models for input with high variability. PMID:25910437

  7. Reduced state estimator for systems with parametric inputs

    Microsoft Academic Search

    PURUSOTTAM MOOKERJEE; FRANK REIFLER

    2004-01-01

    A reduced state estimator is derived for systems with bounded parameters as inputs. Optimal filter gains are derived for minimizing the total covariance of the estimation error due to measurement noise and parameter uncertainty. It is shown that these filter gains for a two-state system with a Gaussian parameter satisfy the Kalata relation in steady state. Equations are also derived

  8. Fundamentals of Image Processing

    E-print Network

    Erdem, Erkut

    A and phase f of the corresponding sine · How can F hold both? Complex number trick! )()()( iIRF += 22 · Method 0: filter the image with eye patch Input Filtered Image ],[],[],[ , lnkmflkgnmh lk ++= What in image · Method 1: filter the image with zero-mean eye Input Filtered Image (scaled) Thresholded

  9. The derivation of water volume reflectances from airborne MSS data using in situ water volume reflectances, and a combined optimization technique and radiative transfer model

    Microsoft Academic Search

    ELIJAH W. RAMSEY III; JOHN R. JENSEN

    1990-01-01

    Water volume reflectance images of three water cooling reservoirs were derived from airborne Daedalus DS-1260 multispectral scanner (MSS) data using a radiative transfer model to eliminate atmospheric effects and to derive downwell-ing irradiances. Sixty in situ water volume reflectances and the associated sensor and sun geometries were input into the radiative transfer model. Using the radiative transfer model to generate

  10. Cross-sensor SAR image offsets for deriving coseismic displacements: Application to the 2001 Bhuj (India) earthquake using ERS and Envisat data

    NASA Astrophysics Data System (ADS)

    Wang, T.; Wei, S.; Jonsson, S.; Avouac, J. P.

    2014-12-01

    Synthetic Aperture Radar (SAR) is a powerful imaging technique for measuring ground deformation, either through Interferometric SAR (InSAR) or image offset tracking. However, these methods are only applied to SAR images acquired by the same satellite, which limits the measurement capability for many earthquakes. Here we propose a novel approach that allows for calculating offsets between images acquired from the European ERS and Envisat satellites. To achieve this cross-sensor offset calculation, we first coregister pre-event (ERS) and post-event (Envisat) SAR images separately to generate averaged pre- and post-event SAR amplitude maps. We then compute the orbital offsets between these two maps in order to resample the ERS average map onto the grid of the averaged Envisat image. We finally calculate the cross-sensor image offsets based on cross-correlating selected sub-images distributed throughout the coregistered averaged SAR maps. Application to the 2001 Bhuj earthquake reveals, for the first time, its near-field coseismic displacement field right above the epicenter. We compare our measurements with the surface displacement field predicted from the published source model of Copley et al. [2011]. This model was derived from tele-seismic waveforms and limited far-field geodetic data. The comparison between the two displacement maps shows consistent displacement patterns, yet a systematic shift, which likely is due to the limited near-fault resolution of the data used in the previous model. We then perform a joint inversion using the newly derived SAR image offsets and tele-seismic waveforms. The preferred source model suggests a compact slip pattern at depths of 20-30 km with a peak slip of ~10 meters and a fairly short rise time (<3s). The large slip rate and low attenuation in the crust are likely responsible for the widely felt ground shaking despite of its compact source area. The result demonstrates that it is possible to correlate non-coherent SAR images acquired by different sensors to measure surface displacements. This approach extends further the possibility of mining the archive of SAR images for various types of earth-science studies.

  11. Vascular fate of adipose tissue-derived adult stromal cells in the ischemic murine brain: A combined imaging-histological study

    Microsoft Academic Search

    Nathalie Kubis; Yutaka Tomita; Alexy Tran-Dinh; Valérie Planat-Benard; Mireille André; Bartosz Karaszewski; Ludovic Waeckel; Luc Pénicaud; Jean-Sébastien Silvestre; Louis Casteilla; Jacques Seylaz; Elisabeth Pinard

    2007-01-01

    Increasing evidence indicates that fat tissue can provide a novel source of progenitor cells with therapeutic potential. Here, the fate of adipose tissue-derived stromal cells (ADSCs) transplanted into the mouse ischemic cortex was monitored in the long term using in vivo imaging, and subsequently characterized. The left middle cerebral artery (MCA) was occluded in C57BL\\/6J mice equipped with a closed

  12. Synthesis of a [2- Pyridinyl- 18F]-labelled fluoro derivative of (?)Cytisine as a candidate radioligand for brain nicotinic ?4?2 receptor imaging with PET

    Microsoft Academic Search

    Gaëlle Roger; Béatrice Lagnel; Jacques Rouden; Laurent Besret; Héric Valette; Stéphane Demphel; JaganMohan Gopisetti; Christine Coulon; Michele Ottaviani; Lori A. Wrenn; Sharon R. Letchworth; Georg A. Bohme; Jesus Benavides; Marie-Claire Lasne; Michel Bottlaendera; Frédéric Dollé

    2003-01-01

    In recent years, there has been considerable effort to design and synthesize radiotracers suitable for use in Positron Emission Tomography (PET) imaging of the ?4?2 neuronal nicotinic acetylcholine receptor (nAChR) subtype. A new fluoropyridinyl derivative of (?)-cytisine (1), namely (?)-9-(2-fluoropyridinyl)cytisine (3, Ki values of 24 and 3462 nM for the ?4?2 and ?7 nAChRs subtypes, respectively) has been synthesized in

  13. Lysine triggered ratiometric conversion of dynamic to static excimer of a pyrene derivative: aggregation-induced emission, nanomolar detection and human breast cancer cell (MCF7) imaging.

    PubMed

    Ghosh, Abhijit; Sengupta, Archya; Chattopadhyay, Ansuman; Das, Debasis

    2015-07-01

    A simple pyrene based probe (A3) derived from pyrene-1-carboxaldehyde and 2-amino-1-phenylpropan-1-ol shows unique optical response triggered by the concentration of lysine (Lys). This allows selective nanomolar detection of Lys via a cascade of processes, dynamic to static-excimer conversion in a ratiometric manner followed by aggregation-induced emission (AIE). Imaging of Lys in the human breast cancer cell (MCF7) has been achieved. PMID:26090534

  14. Erythrocyte-derived photo-theranostic agents: hybrid nano-vesicles containing indocyanine green for near infrared imaging and therapeutic applications

    NASA Astrophysics Data System (ADS)

    Bahmani, Baharak; Bacon, Danielle; Anvari, Bahman

    2013-07-01

    Development of theranostic nano-constructs may enable diagnosis and treatment of diseases at high spatial resolution. Some key requirements for clinical translation of such constructs are that they must be non-toxic, non-immunogenic, biodegradable, with extended circulating lifetime. Cell-based structures, particularly those derived from erythrocytes, are promising candidate carrier systems to satisfy these requirements. One particular type of theranostic materials utilize light-sensitive agents that once photo-activated can provide diagnostic imaging capability, and elicit therapeutic effects. Here we demonstrate the first successful engineering of hybrid nano-scale constructs derived from membranes of hemoglobin-depleted erythrocytes that encapsulate the near infrared chromophore, indocyanine green. We show the utility of the constructs as photo-theranostic agents in fluorescence imaging and photothermal destruction of human cells. These erythrocyte-mimicking nano-structures can be derived autologously, and may have broad applications in personal nanomedicine ranging from imaging and photo-destruction of cancerous tissues to vascular abnormalities, and longitudinal evaluations of therapeutic interventions.

  15. Eur J Nucl Med Mol Imaging . Author manuscript Baseline F-FDG PET image-derived parameters for therapy response18

    E-print Network

    Paris-Sud XI, Université de

    ] pathological response with no residual cancer cells in the primary tumour or lymph nodes . A complete responseEur J Nucl Med Mol Imaging . Author manuscript Page /1 16 Baseline F-FDG PET image of this study were to investigate the predictive value of tumour measurements on 18F-FDG PET pretreatment scan

  16. Comparison of point clouds derived from aerial image matching with data from airborne laser scanning. (Polish Title: Porównanie wóa?ciwo?ci chmury punktów wygenerowanej metod? dopasowania obrazów zdj?? lotniczych z danymi z lotniczego skanowania)

    NASA Astrophysics Data System (ADS)

    Dominik, W.

    2014-12-01

    The aim of this study was to investigate the properties of point clouds derived from aerial image matching and to compare them with point clouds from airborne laser scanning. A set of aerial images acquired in years 2010-2013 over the city of Elblag were used for the analysis. Images were acquired with the use of three digital cameras: DMC II 230, DMC I and DigiCAM60 with a GSD varying from 4.5 cm to 15 cm. Eight sets of images that were used in the study were acquired at different stages of the growing season - from March to December. Two LiDAR point clouds were used for the comparison - one with a density of 1.3 p/m2 and a second with a density of 10 p/m2. Based on the input images point clouds were created with the use of the semi-global matching method. The properties of the obtained point clouds were analyzed in three ways: - by the comparison of the vertical accuracy of point clouds with reference to a terrain profile surveyed on bare ground with GPS-RTK method - by visual assessment of point cloud profiles generated both from SGM and LiDAR point clouds - by visual assessment of a digital surface model generated from a SGM point cloud with reference to a digital surface model generated from a LiDAR point cloud. The conducted studies allowed a number of observations about the quality of SGM point clouds to be formulated with respect to different factors. The main factors having influence on the quality of SGM point clouds are GSD and base/height ratio. The essential problem related to SGM point clouds are areas covered with vegetation where SGM point clouds are visibly worse in terms of both accuracy and the representation of terrain surface. It is difficult to expect that in these areas SGM point clouds could replace LiDAR point clouds. This leads to a general conclusion that SGM point clouds are less reliable, more unpredictable and are dependent on more factors than LiDAR point clouds. Nevertheless, SGM point clouds generated with appropriate parameters can have better accuracy than LiDAR point clouds and present more detailed information about the terrain surface.

  17. Images

    Cancer.gov

    Home News and Events Multimedia Library Images Images:  Cancer Biology Image: Cell with DNA 72 DPI | 300 DPIDrawing depicting DNA molecule unwinding from a chromosome inside the nucleus of a cell. NHGRI >> View All Cancer Pathology/Imaging Image: Female

  18. Segmentation and learning in the quantitative analysis of microscopy images

    NASA Astrophysics Data System (ADS)

    Ruggiero, Christy; Ross, Amy; Porter, Reid

    2015-02-01

    In material science and bio-medical domains the quantity and quality of microscopy images is rapidly increasing and there is a great need to automatically detect, delineate and quantify particles, grains, cells, neurons and other functional "objects" within these images. These are challenging problems for image processing because of the variability in object appearance that inevitably arises in real world image acquisition and analysis. One of the most promising (and practical) ways to address these challenges is interactive image segmentation. These algorithms are designed to incorporate input from a human operator to tailor the segmentation method to the image at hand. Interactive image segmentation is now a key tool in a wide range of applications in microscopy and elsewhere. Historically, interactive image segmentation algorithms have tailored segmentation on an image-by-image basis, and information derived from operator input is not transferred between images. But recently there has been increasing interest to use machine learning in segmentation to provide interactive tools that accumulate and learn from the operator input over longer periods of time. These new learning algorithms reduce the need for operator input over time, and can potentially provide a more dynamic balance between customization and automation for different applications. This paper reviews the state of the art in this area, provides a unified view of these algorithms, and compares the segmentation performance of various design choices.

  19. Selection of weighting factors for quantification of PET radioligand binding using simplified reference tissue models with noisy input functions

    NASA Astrophysics Data System (ADS)

    Normandin, M. D.; Koeppe, R. A.; Morris, E. D.

    2012-02-01

    Input function noise contributes to model-predicted values and should be accounted for during parameter estimation. This problem has been examined in the context of PET data analysis using a noisy image-derived arterial input function. Huesman and Mazoyer (1987 Phys. Med. Biol 32 1569-79) incorporated the effect of error in the measured input function into the objective function and observed a subsequent improvement in the accuracy of parameters estimated from a kinetic model of cardiac blood flow. Such a treatment has not been applied to the reference region models commonly used to analyze dynamic positron emission tomography data with receptor-ligand tracers. Here, we propose a strategy for selection of weighting factors that accounts for noise in the reference region input function and test the method on two common formulations of the simplified reference tissue model (SRTM). We present a simulation study which demonstrates that the proposed weighting approach improves the accuracy of estimated binding potential at high noise levels and when the reference tissue and target regions of interest are of comparable size. In the second simulation experiment, we show that using a small, homogeneous reference tissue with our weighting technique may have advantages over input functions derived from a larger (and thus less noisy), heterogeneous region with conventional weighting. A comparative analysis of clinical [11C]flumazenil data found a small but significant increase in estimated binding potential when using the proposed weighting method, consistent with the finding of reduced negative bias in our simulation study. The weighting strategy described here accounts for noise in the reference region input function and may improve the performance of the SRTM in applications where data are noisy and the reference region is relatively small. This technique may offer similar benefits to other models using reference region inputs, particularly those derived from the SRTM.

  20. Genie Pro: robust image classification using shape, texture, and spectral information

    Microsoft Academic Search

    Simon Perkins; Kim Edlund; Diana Esch-Mosher; Damian Eads; Neal Harvey; Steven Brumby

    2005-01-01

    We present Genie Pro, a new software tool for image analysis produced by the ISIS (Intelligent Search in Images and Signals) group at Los Alamos National Laboratory. Like the earlier GENIE tool produced by the same group, Genie Pro is a general purpose adaptive tool that derives automatic pixel classification algorithms for satellite\\/aerial imagery, from training input provided by a

  1. Automatic landslide detection from remote sensing images using supervised classification methods

    Microsoft Academic Search

    Gaelle Danneels; Eric Pirard; Hans-Balder Havenith

    2007-01-01

    The creation of a landslide inventory map by manual interpretation of remote sensing images is very time-consuming. This study aims at developing an automated procedure for the detection of landslides from multi-spectral remote sensing images. According to the type of landslide, the parameters for detecting the slope instabilities will differ. In a first step, predefined input parameters derived from the

  2. MODELLING DISCRETE INPUT PROBABILITY DISTRIBUTIONS

    E-print Network

    Strelen, Christoph

    MODELLING DISCRETE INPUT PROBABILITY DISTRIBUTIONS Johann Christoph Strelen Rheinische Friedrich Probability Distributions, Dis- crete Probability Distributions, Genetic Algorithm, Inverse Transformation Method. ABSTRACT Sometimes input probability distributions for stochastic models are not so simple

  3. Virtual input device with diffractive optical element

    NASA Astrophysics Data System (ADS)

    Wu, Ching Chin; Chu, Chang Sheng

    2005-02-01

    As a portable device, such as PDA and cell phone, a small size build in virtual input device is more convenient for complex input demand. A few years ago, a creative idea called 'virtual keyboard' is announced, but up to now there's still no mass production method for this idea. In this paper we'll show the whole procedure of making a virtual keyboard. First of all is the HOE (Holographic Optical Element) design of keyboard image which yields a fan angle about 30 degrees, and then use the electron forming method to copy this pattern in high precision. And finally we can product this element by inject molding. With an adaptive lens design we can get a well correct keyboard image in distortion and a wilder fan angle about 70 degrees. With a batter alignment of HOE pattern lithography, we"re sure to get higher diffraction efficiency.

  4. Intensive Input in Language Acquisition.

    ERIC Educational Resources Information Center

    Trimino, Andy; Ferguson, Nancy

    This paper discusses the role of input as one of the universals in second language acquisition theory. Considerations include how language instructors can best organize and present input and when certain kinds of input are more important. A self-administered program evaluation exercise using relevant theoretical and methodological contributions…

  5. Aerosol and Cloud Properties at the Huygens Entry Site as Derived from the Descent Imager/Spectral

    NASA Technical Reports Server (NTRS)

    Doose, L. R.; Engel, S.; Tomasko, M. G.; Dafoe, L. E.; West, R.; Lemmon, M.

    2005-01-01

    The Huygens Probe descended through Titan s atmosphere on January 14, 2005. The Descent Imager/Spectral Radiometer (DISR) instrument made optical measurements which constrain the nature and vertical distribution and of the aerosols in the atmosphere.

  6. Reliability of MRI-derived cortical and subcortical morphometric measures: Effects of pulse sequence, voxel geometry, and parallel imaging

    E-print Network

    Corkin, Suzanne

    Reliability of MRI-derived cortical and subcortical morphometric measures: Effects of pulse of downstream morphometric measures has not been extensively studied. We examined how MRI methods could have a considerable impact on the reproducibility of morphometric measures. In addition

  7. Ipsilateral Hand Input to Area 3b Revealed by Converging Hemodynamic and Electrophysiological Analyses in Macaque Monkeys

    PubMed Central

    Lipton, Michael L.; Fu, Kai-Ming G.; Branch, Craig A.; Schroeder, Charles E.

    2015-01-01

    Functional magnetic resonance imaging (fMRI) of the hand representation in primary somatosensory cortex (area 3b) of macaque monkeys revealed an ipsilateral hand input undetected by most previous studies. Ipsilateral responses had a hemodynamic signature indistinguishable from that of contralateral hand responses. We explored the neural mechanisms of the fMRI effects using a second derivative analysis of field potentials [current source density (CSD) analysis] combined with action potential profiles, sampled from area 3b using linear array multielectrodes. In contrast to the predominantly excitatory contralateral response, the colocated ipsilateral response appeared dominated by inhibition, suggesting that ipsilateral inputs may have modulatory effects on contralateral input processing. Our findings confirm bimanual convergence at the earliest stage of cortical somatosensory processing in primates. They also illustrate the value of combined CSD and fMRI analyses in monkeys for defining hidden aspects of sensory function and for investigating the neuronal processes generating fMRI signals. PMID:16399685

  8. Synthesis of superparamagnetic iron oxide nanoparticles coated with a DDNP-carboxyl derivative for in vitro magnetic resonance imaging of Alzheimer's disease.

    PubMed

    Zhou, Jingting; Fa, Huanbao; Yin, Wei; Zhang, Jin; Hou, Changjun; Huo, Danqun; Zhang, Dong; Zhang, Haifeng

    2014-04-01

    Superparamagnetic iron oxide nanoparticles (SPIONs) have been proposed for use in magnetic resonance imaging as versatile ultra-sensitive nanoprobes for Alzheimer's disease imaging. In this work, we synthetized an efficient contrast agent of Alzheimer's disease using 1,1-dicyano-2-[6-(dimethylamino)naphthalene-2-yl]propene (DDNP) carboxyl derivative to functionalize the surface of SPIONs. The DDNP-SPIONs are prepared by conjugating DDNP carboxyl derivative to oleic acid-treated SPIONs through ligand exchange. The structure, size distribution and magnetic property were identified by IR, TGA-DTA, XRD, TEM, Zetasizer Nano and VSM. TEM and Zetasizer Nano observations indicated that the DDNP-SPIONs are relatively mono-dispersed spherical distribution with an average size of 11.7nm. The DDNP-SPIONs were then further analyzed for their MRI relaxation properties using MR imaging and demonstrated high T2 relaxivity of 140.57s(-1)FemM(-1), and the vitro experiment that DDNP-SPIONs binding to ?-Amyloid aggregates were then investigated by fluorophotometry, the results showed that the combination had induced the fluorescence enhancement of the DDNP-SPIONs and displayed tremendous promise for use as a contrast agent of Alzheimer's disease in MRI. PMID:24582259

  9. Small Iminocoumarin Derivatives as Red Emitters: From Biological Imaging to Highly Photoluminescent Non-doped Micro- and Nanofibres.

    PubMed

    Khemakhem, Kacem; Soulié, Marine; Brousses, Rémy; Ammar, Houcine; Abid, Souhir; Fery-Forgues, Suzanne

    2015-05-18

    The fluorescence properties of four derivatives of 3-thienyl-2-(N-dicyanovinyl)iminocoumarin, bearing a diethylamino group in the 7-position or a methoxy group in the 6, 7 and 8 positions, were compared in solution and in the solid state. The 7-diethylamino derivative was strongly fluorescent in various solvents, with marked solvatochromism. Its fluorescence was quenched by aggregation. In contrast, the methoxy derivatives were only moderately or weakly fluorescent in solution, but two of them were strongly photoluminescent in the crystalline state, owing to favourable molecular packing. The 6-methoxy derivative even exhibited spectacular crystallization-enhanced emission, examples of which are particularly rare for this type of dyes. Dyes were tested for biological use. The 7-diethylamino derivative led to particularly strong fluorescence staining of the cytoplasm of HCT-116 colon cancer cells. No fading was observed over prolonged illumination by the microscope light beam, but a phototoxic effect was detected. The use of the dyes as red-emitting materials was also investigated. Using easy-to-implement preparation methods, the compounds self- assembled to give one-dimensional nano- and microsized particles, including millimeter-long microfibres that exhibited clear wave-guiding properties. This study shows the value of these low molecular-weight molecules for the preparation of new orange and red-emitting fluorescent materials based on totally pure dye. PMID:25873140

  10. Combined Optical Imaging and Mammography of the Healthy Breast: Optical Contrast Derived From Breast Structure and Compression

    PubMed Central

    Fang, Qianqian; Carp, Stefan A.; Selb, Juliette; Boverman, Greg; Zhang, Quan; Kopans, Daniel B.; Moore, Richard H.; Miller, Eric L.; Brooks, Dana H.; Boas, David A.

    2009-01-01

    In this paper, we report new progress in developing the instrument and software platform of a combined X-ray mammography/diffuse optical breast imaging system. Particularly, we focus on system validation using a series of balloon phantom experiments and the optical image analysis of 49 healthy patients. Using the finite-element method for forward modeling and a regularized Gauss-Newton method for parameter reconstruction, we recovered the inclusions inside the phantom and the hemoglobin images of the human breasts. An enhanced coupling coefficient estimation scheme was also incorporated to improve the accuracy and robustness of the reconstructions. The recovered average total hemoglobin concentration (HbT) and oxygen saturation (SO2) from 68 breast measurements are 16.2 ?m and 71%, respectively, where the HbT presents a linear trend with breast density. The low HbT value compared to literature is likely due to the associated mammographic compression. From the spatially co-registered optical/X-ray images, we can identify the chest-wall muscle, fatty tissue, and fibroglandular regions with an average HbT of 20.1±6.1 ?m for fibroglandular tissue, 15.4±5.0 ?m for adipose, and 22.2±7.3 ?m for muscle tissue. The differences between fibroglandular tissue and the corresponding adipose tissue are significant (p < 0.0001). At the same time, we recognize that the optical images are influenced, to a certain extent, by mammographical compression. The optical images from a subset of patients show composite features from both tissue structure and pressure distribution. We present mechanical simulations which further confirm this hypothesis. PMID:19116186

  11. Use of a beta microprobe system to measure arterial input function in PET via an arteriovenous shunt in rats

    PubMed Central

    2011-01-01

    Background Kinetic modeling of physiological function using imaging techniques requires the accurate measurement of the time-activity curve of the tracer in plasma, known as the arterial input function (IF). The measurement of IF can be achieved through manual blood sampling, the use of small counting systems such as beta microprobes, or by derivation from PET images. Previous studies using beta microprobe systems to continuously measure IF have suffered from high background counts. Methods In the present study, a light-insensitive beta microprobe with a temporal resolution of up to 1 s was used in combination with a pump-driven femoral arteriovenous shunt to measure IF in rats. The shunt apparatus was designed such that the placement of the beta microprobe was highly reproducible. The probe-derived IF was compared to that obtained from manual sampling at 5-s intervals and IF derived from a left ventricle VOI in a dynamic PET image of the heart. Results Probe-derived IFs were very well matched to that obtained by "gold standard" manual blood sampling, but with an increased temporal resolution of up to 1 s. The area under the curve (AUC) ratio between probe- and manually derived IFs was 1.07 ± 0.05 with a coefficient of variation of 0.04. However, image-derived IFs were significantly underestimated compared to the manually sampled IFs, with an AUC ratio of 0.76 ± 0.24 with a coefficient of variation of 0.32. Conclusions IF derived from the beta microprobe accurately represented the IF as measured by blood sampling, was reproducible, and was more accurate than an image-derived technique. The use of the shunt removed problems of tissue-background activity, and the use of a light-tight probe with minimal gamma sensitivity refined the system. The probe/shunt apparatus can be used in both microprobe and PET studies. PMID:22214227

  12. Comparison of correlation performance of smart ternary phase-amplitude filters with gray-scale and binary input scenes

    NASA Astrophysics Data System (ADS)

    Flannery, David L.; Phillips, William E., III; Reel, Richard L.; Goldstein, Dennis H.

    1992-07-01

    The ternary phase-amplitude filter (TPAF) is by definition restricted to the modulation values -1, 0, and 1, thus comprising a binary phase-only filter (BPOF) multiplied by a binary- amplitude pattern, i.e., a region of support. The TPAF offers an attractive combination of real-time implementation with available devices and good correlation performance. Smart (optimized distortion-invariant) TPAF formulations have been developed. The TPAF enables filter implementation with magneto-optic devices and these devices also can also be used for image input if gray scale scenes can be binarized while preserving good correlation performance. We provide simulation results addressing the comparative performance of TPAF correlation using gray scale and binary images derived from identical edge-enhanced version of original scenes. Experimental correlations verifying the results for the binary input cases are provided.

  13. Stem cell derived in vivo-like human cardiac bodies in a microfluidic device for toxicity testing by beating frequency imaging.

    PubMed

    Bergström, Gunnar; Christoffersson, Jonas; Schwanke, Kristin; Zweigerdt, Robert; Mandenius, Carl-Fredrik

    2015-07-14

    Beating in vivo-like human cardiac bodies (CBs) were used in a microfluidic device for testing cardiotoxicity. The CBs, cardiomyocyte cell clusters derived from induced pluripotent stem cells, exhibited typical structural and functional properties of the native human myocardium. The CBs were captured in niches along a perfusion channel in the device. Video imaging was utilized for automatic monitoring of the beating frequency of each individual CB. The device allowed assessment of cardiotoxic effects of drug substances doxorubicin, verapamil and quinidine on the 3D clustered cardiomyocytes. Beating frequency data recorded over a period of 6 hours are presented and compared to literature data. The results indicate that this microfluidic setup with imaging of CB characteristics provides a new opportunity for label-free, non-invasive investigation of toxic effects in a 3D microenvironment. PMID:26135270

  14. SDR Input Power Estimation Algorithms

    NASA Technical Reports Server (NTRS)

    Nappier, Jennifer M.; Briones, Janette C.

    2013-01-01

    The General Dynamics (GD) S-Band software defined radio (SDR) in the Space Communications and Navigation (SCAN) Testbed on the International Space Station (ISS) provides experimenters an opportunity to develop and demonstrate experimental waveforms in space. The SDR has an analog and a digital automatic gain control (AGC) and the response of the AGCs to changes in SDR input power and temperature was characterized prior to the launch and installation of the SCAN Testbed on the ISS. The AGCs were used to estimate the SDR input power and SNR of the received signal and the characterization results showed a nonlinear response to SDR input power and temperature. In order to estimate the SDR input from the AGCs, three algorithms were developed and implemented on the ground software of the SCAN Testbed. The algorithms include a linear straight line estimator, which used the digital AGC and the temperature to estimate the SDR input power over a narrower section of the SDR input power range. There is a linear adaptive filter algorithm that uses both AGCs and the temperature to estimate the SDR input power over a wide input power range. Finally, an algorithm that uses neural networks was designed to estimate the input power over a wide range. This paper describes the algorithms in detail and their associated performance in estimating the SDR input power.

  15. Intermediate inputs and economic productivity.

    PubMed

    Baptist, Simon; Hepburn, Cameron

    2013-03-13

    Many models of economic growth exclude materials, energy and other intermediate inputs from the production function. Growing environmental pressures and resource prices suggest that this may be increasingly inappropriate. This paper explores the relationship between intermediate input intensity, productivity and national accounts using a panel dataset of manufacturing subsectors in the USA over 47 years. The first contribution is to identify sectoral production functions that incorporate intermediate inputs, while allowing for heterogeneity in both technology and productivity. The second contribution is that the paper finds a negative correlation between intermediate input intensity and total factor productivity (TFP)--sectors that are less intensive in their use of intermediate inputs have higher productivity. This finding is replicated at the firm level. We propose tentative hypotheses to explain this association, but testing and further disaggregation of intermediate inputs is left for further work. Further work could also explore more directly the relationship between material inputs and economic growth--given the high proportion of materials in intermediate inputs, the results in this paper are suggestive of further work on material efficiency. Depending upon the nature of the mechanism linking a reduction in intermediate input intensity to an increase in TFP, the implications could be significant. A third contribution is to suggest that an empirical bias in productivity, as measured in national accounts, may arise due to the exclusion of intermediate inputs. Current conventions of measuring productivity in national accounts may overstate the productivity of resource-intensive sectors relative to other sectors. PMID:23359736

  16. A simple derivation and analysis of a helical cone beam tomographic algorithm for long object imaging via a novel definition of region of interest

    NASA Astrophysics Data System (ADS)

    Hu, Jicun; Tam, Kwok; Johnson, Roger H.

    2004-01-01

    We derive and analyse a simple algorithm first proposed by Kudo et al (2001 Proc. 2001 Meeting on Fully 3D Image Reconstruction in Radiology and Nuclear Medicine (Pacific Grove, CA) pp 7-10) for long object imaging from truncated helical cone beam data via a novel definition of region of interest (ROI). Our approach is based on the theory of short object imaging by Kudo et al (1998 Phys. Med. Biol. 43 2885-909). One of the key findings in their work is that filtering of the truncated projection can be divided into two parts: one, finite in the axial direction, results from ramp filtering the data within the Tam window. The other, infinite in the z direction, results from unbounded filtering of ray sums over PI lines only. We show that for an ROI defined by PI lines emanating from the initial and final source positions on a helical segment, the boundary data which would otherwise contaminate the reconstruction of the ROI can be completely excluded. This novel definition of the ROI leads to a simple algorithm for long object imaging. The overscan of the algorithm is analytically calculated and it is the same as that of the zero boundary method. The reconstructed ROI can be divided into two regions: one is minimally contaminated by the portion outside the ROI, while the other is reconstructed free of contamination. We validate the algorithm with a 3D Shepp-Logan phantom and a disc phantom.

  17. Teaching Image Formation by Extended Light Sources: The Use of a Model Derived from the History of Science

    ERIC Educational Resources Information Center

    Dedes, Christos; Ravanis, Konstantinos

    2009-01-01

    This research, carried out in Greece on pupils aged 12-16, focuses on the transformation of their representations concerning light emission and image formation by extended light sources. The instructive process was carried out in two stages, each one having a different, distinct target set. During the first stage, the appropriate conflict…

  18. Medical image integrity control and forensics based on watermarking--approximating local modifications and identifying global image alterations.

    PubMed

    Huang, H; Coatrieux, G; Shu, H Z; Luo, L M; Roux, Ch

    2011-01-01

    In this paper we present a medical image integrity verification system that not only allows detecting and approximating malevolent local image alterations (e.g. removal or addition of findings) but is also capable to identify the nature of global image processing applied to the image (e.g. lossy compression, filtering …). For that purpose, we propose an image signature derived from the geometric moments of pixel blocks. Such a signature is computed over regions of interest of the image and then watermarked in regions of non interest. Image integrity analysis is conducted by comparing embedded and recomputed signatures. If any, local modifications are approximated through the determination of the parameters of the nearest generalized 2D Gaussian. Image moments are taken as image features and serve as inputs to one classifier we learned to discriminate the type of global image processing. Experimental results with both local and global modifications illustrate the overall performances of our approach. PMID:22256212

  19. Modelling solar irradiance from HRV images of Meteosat Second Generation

    Microsoft Academic Search

    Marco Cony; Luis Zarzalejo; Jesús Polo; Ruth Marchante; Luis Martín

    2010-01-01

    Knowledge of solar radiation at the earth's surface is a need in designing any solar energy application. In particular both photovoltaic and solar thermal systems required high accurate data of solar radiation components. Nowadays the use of satellite images as input to models for deriving solar irradiance time series is accepted as a reliable methodology with good accuracy. In this

  20. Input validation analysis and testing

    Microsoft Academic Search

    Jane Huffman Hayes; Jeff Offutt

    2006-01-01

    This research addresses the problem of statically analyzing input command syntax as defined in interface and requirements specifications and then generating test cases for dynamic input validation testing. The IVAT (Input Validation Analysis and Testing) technique has been developed, a proof-of-concept tool (MICASA) has been implemented, and a case study validation has been performed. Empirical validation on large-scale industrial software

  1. Comparing irradiance fields derived from Moderate Resolution Imaging Spectroradiometer airborne simulator cirrus cloud retrievals with solar spectral flux radiometer measurements

    Microsoft Academic Search

    K. Sebastian Schmidt; Peter Pilewskie; Steven Platnick; Gala Wind; Ping Yang; Manfred Wendisch

    2007-01-01

    During the Cirrus Regional Study of Tropical Anvils and Cirrus Layers–Florida Area Cirrus Experiment, the Moderate Resolution Imaging Spectroradiometer (MODIS) airborne simulator (MAS) and the solar spectral flux radiometer (SSFR) operated on the same aircraft, the NASA ER-2. While MAS provided two-dimensional horizontal fields of cloud optical thickness and effective ice particle radius, the SSFR measured spectral irradiance in the

  2. Images of Gravitational and Magnetic Phenomena Derived from Two-dimensional Back-projection Doppler Tomography of Interacting Binary Stars

    NASA Astrophysics Data System (ADS)

    Richards, Mercedes T.; Cocking, Alexander S.; Fisher, John G.; Conover, Marshall J.

    2014-11-01

    We have used two-dimensional back-projection Doppler tomography as a tool to examine the influence of gravitational and magnetic phenomena in interacting binaries that undergo mass transfer from a magnetically active star onto a non-magnetic main-sequence star. This multitiered study of over 1300 time-resolved spectra of 13 Algol binaries involved calculations of the predicted dynamical behavior of the gravitational flow and the dynamics at the impact site, analysis of the velocity images constructed from tomography, and the influence on the tomograms of orbital inclination, systemic velocity, orbital coverage, and shadowing. The H? tomograms revealed eight sources: chromospheric emission, a gas stream along the gravitational trajectory, a star-stream impact region, a bulge of absorption or emission around the mass-gaining star, a Keplerian accretion disk, an absorption zone associated with hotter gas, a disk-stream impact region, and a hot spot where the stream strikes the edge of a disk. We described several methods used to extract the physical properties of the emission sources directly from the velocity images, including S-wave analysis, the creation of simulated velocity tomograms from hydrodynamic simulations, and the use of synthetic spectra with tomography to sequentially extract the separate sources of emission from the velocity image. In summary, the tomography images have revealed results that cannot be explained solely by gravitational effects: chromospheric emission moving with the mass-losing star, a gas stream deflected from the gravitational trajectory, and alternating behavior between stream state and disk state. Our results demonstrate that magnetic effects cannot be ignored in these interacting binaries.

  3. Micro-CT image-derived metrics quantify arterial wall distensibility reduction in a rat model of pulmonary hypertension

    NASA Astrophysics Data System (ADS)

    Johnson, Roger H.; Karau, Kelly L.; Molthen, Robert C.; Haworth, Steven T.; Dawson, Christopher A.

    2000-04-01

    We developed methods to quantify arterial structural and mechanical properties in excised rat lungs and applied them to investigate the distensibility decrease accompanying chronic hypoxia-induced pulmonary hypertension. Lungs of control and hypertensive (three weeks 11% O2) animals were excised and a contrast agent introduced before micro-CT imaging with a special purpose scanner. For each lung, four 3D image data sets were obtained, each at a different intra-arterial contrast agent pressure. Vessel segment diameters and lengths were measured at all levels in the arterial tree hierarchy, and these data used to generate features sensitive to distensibility changes. Results indicate that measurements obtained from 3D micro-CT images can be used to quantify vessel biomechanical properties in this rat model of pulmonary hypertension and that distensibility is reduced by exposure to chronic hypoxia. Mechanical properties can be assessed in a localized fashion and quantified in a spatially-resolved way or as a single parameter describing the tree as a whole. Micro-CT is a nondestructive way to rapidly assess structural and mechanical properties of arteries in small animal organs maintained in a physiological state. Quantitative features measured by this method may provide valuable insights into the mechanisms causing the elevated pressures in pulmonary hypertension of differing etiologies and should become increasingly valuable tools in the study of complex phenotypes in small-animal models of important diseases such as hypertension.

  4. Entropy-based measures of in vivo cilia-driven microfluidic mixing derived from quantitative optical imaging

    NASA Astrophysics Data System (ADS)

    Chandrasekera, Kenny; Jonas, Stephan; Bhattacharya, Dipankan; Khokha, Mustafa; Choma, Michael A.

    2012-02-01

    Motile cilia are cellular organelles that project from different epithelial surfaces including respiratory epithelium. They generate directional fluid flow that removes harmful pathogens and particulate matter from the respiratory system. While it has been known that primary ciliary dyskinesia increases the risk of recurrent pulmonary infections, there is now heightened interest in understanding the role that cilia play in a wide-variety of respiratory diseases. Different optical imaging technologies are being investigated to visualize cilia-driven fluid flow, and quantitative image analysis is used to generate measures of ciliary performance. Here, we demonstrate the quantification of in vivo cilia-driven microfluidic mixing using spatial and temporal measures of Shannon information entropy. Using videomicroscopy, we imaged in vivo cilia-driven fluid flow generated by the epidermis of the Xenopus tropicalis embryo. Flow was seeded with either dyes or microparticles. Both spatial and temporal measures of entropy show significant levels of mixing, with maximum entropy measures of ~6.5 (out of a possible range of 0 to 8). Spatial entropy measures showed localization of mixing "hot-spots" and "cold-spots" and temporal measures showed mixing throughout.In sum, entropy-based measures of microfluidic mixing can characterize in vivo cilia-driven fluid flow and hold the potential for better characterization of ciliary dysfunction.

  5. Correction of gradient echo images for first and second order macroscopic signal dephasing using phase derivative mapping.

    PubMed

    de Leeuw, H; Bakker, C J G

    2012-03-01

    Gradient echo techniques are often hampered by signal dephasing due to macroscopic phase perturbations because of system imperfections (shimming) or object induced perturbations of the magnetic field (hemorrhagic lesions, calcified tissue, air-tissue interfaces). Many techniques have been proposed to reduce the effects of macroscopic phase variations. Among these techniques are tuned pulse sequences, fitting techniques and reconstruction algorithms. These methods, however, suffer from one or more of the following drawbacks: they require longer acquisition times, require additional acquisitions, compensate only locally, can only be applied to multi-gradient echo data or may result in inaccurate results. In this work a generally applicable post-processing technique is presented to evaluate and compensate signal alterations invoked by first and second order macroscopic phase incoherences. In this technique, the derivatives of the signal phase are determined by applying the Fourier derivative theorem on the complex data. As a result, the phase derivatives are obtained without phase unwrapping and without compromising the resolution. The method is validated for single and multi-echo acquisitions by experiments on a co-axial cylinder phantom with known macroscopic field disturbances. The potential of the method is demonstrated on a multi-gradient echo acquisition on the head of a human volunteer. In general a first order correction is shown to be sufficient, however higher order correction is found to be beneficial near sharp transitions of the magnetic field. PMID:22155330

  6. Input a journal Viewing Journals

    E-print Network

    Sussex, University of

    Journals Contents: Input a journal Viewing Journals Deleting a journal Entering jnl into different period Problems Input a journal 1 Login to Bluqube 2 Select 3 Enter relevant Doc type To select the number of journals you will processing & the total credit value 6 Click on 7 Enter brief description 8

  7. High-resolution intravital imaging reveals that blood-derived macrophages but not resident microglia facilitate secondary axonal dieback in traumatic spinal cord injury.

    PubMed

    Evans, Teresa A; Barkauskas, Deborah S; Myers, Jay T; Hare, Elisabeth G; You, Jing Qiang; Ransohoff, Richard M; Huang, Alex Y; Silver, Jerry

    2014-04-01

    After traumatic spinal cord injury, functional deficits increase as axons die back from the center of the lesion and the glial scar forms. Axonal dieback occurs in two phases: an initial axon intrinsic stage that occurs over the first several hours and a secondary phase which takes place over the first few weeks after injury. Here, we examine the secondary phase, which is marked by infiltration of macrophages. Using powerful time-lapse multi-photon imaging, we captured images of interactions between Cx3cr1(+/GFP) macrophages and microglia and Thy-1(YFP) axons in a mouse dorsal column crush spinal cord injury model. Over the first few weeks after injury, axonal retraction bulbs within the lesion are static except when axonal fragments are lost by a blebbing mechanism in response to physical contact followed by phagocytosis by mobile Cx3Cr1(+/GFP) cells. Utilizing a radiation chimera model to distinguish marrow-derived cells from radio-resistant CNS-resident microglia, we determined that the vast majority of accumulated cells in the lesion are derived from the blood and only these are associated with axonal damage. Interestingly, CNS-resident Cx3Cr1(+/GFP) microglia did not increasingly accumulate nor participate in neuronal destruction in the lesion during this time period. Additionally, we found that the blood-derived cells consisted mainly of singly labeled Ccr2(+/RFP) macrophages, singly labeled Cx3Cr1(+/GFP) macrophages and a small population of double-labeled cells. Since all axon destructive events were seen in contact with a Cx3Cr1(+/GFP) cell, we infer that the CCR2 single positive subset is likely not robustly involved in axonal dieback. Finally, in our model, deletion of CCR2, a chemokine receptor, did not alter the position of axons after dieback. Understanding the in vivo cellular interactions involved in secondary axonal injury may lead to clinical treatment candidates involving modulation of destructive infiltrating blood monocytes. PMID:24468477

  8. Image Processing Apr. 16, 2012

    E-print Network

    Erdem, Erkut

    the amplitude A and phase f of the corresponding sine · How can F hold both? Complex number trick! )()()( i · Goal: find in image · Method 0: filter the image with eye patch Input Filtered Image with zero-mean eye Input Filtered Image (scaled) Thresholded Image )],[()],[(],[ , lnkmgflkfnmh lk

  9. Images

    Microsoft Academic Search

    Russell K. Hobbie; Bradley J. Roth

    Images are very important in the remainder of this book. They may be formed by the eye, a camera, an xray machine, a nuclear\\u000a medicine camera, magnetic resonance imaging, or ultrasound. The concepts developed in Chapter 11 can be used to understand\\u000a and describe image quality. The same concepts are also used to reconstruct computed tomographic or magnetic resonance slice

  10. Deriving urban dynamic evolution rules from self-adaptive cellular automata with multi-temporal remote sensing images

    NASA Astrophysics Data System (ADS)

    He, Yingqing; Ai, Bin; Yao, Yao; Zhong, Fajun

    2015-06-01

    Cellular automata (CA) have proven to be very effective for simulating and predicting the spatio-temporal evolution of complex geographical phenomena. Traditional methods generally pose problems in determining the structure and parameters of CA for a large, complex region or a long-term simulation. This study presents a self-adaptive CA model integrated with an artificial immune system to discover dynamic transition rules automatically. The model's parameters are allowed to be self-modified with the application of multi-temporal remote sensing images: that is, the CA can adapt itself to the changed and complex environment. Therefore, urban dynamic evolution rules over time can be efficiently retrieved by using this integrated model. The proposed AIS-based CA model was then used to simulate the rural-urban land conversion of Guangzhou city, located in the core of China's Pearl River Delta. The initial urban land was directly classified from TM satellite image in the year 1990. Urban land in the years 1995, 2000, 2005, 2009 and 2012 was correspondingly used as the observed data to calibrate the model's parameters. With the quantitative index figure of merit (FoM) and pattern similarity, the comparison was further performed between the AIS-based model and a Logistic CA model. The results indicate that the AIS-based CA model can perform better and with higher precision in simulating urban evolution, and the simulated spatial pattern is closer to the actual development situation.

  11. Comparison of temporal and spectral scattering methods using acoustically large breast models derived from magnetic resonance images.

    PubMed

    Hesford, Andrew J; Tillett, Jason C; Astheimer, Jeffrey P; Waag, Robert C

    2014-08-01

    Accurate and efficient modeling of ultrasound propagation through realistic tissue models is important to many aspects of clinical ultrasound imaging. Simplified problems with known solutions are often used to study and validate numerical methods. Greater confidence in a time-domain k-space method and a frequency-domain fast multipole method is established in this paper by analyzing results for realistic models of the human breast. Models of breast tissue were produced by segmenting magnetic resonance images of ex vivo specimens into seven distinct tissue types. After confirming with histologic analysis by pathologists that the model structures mimicked in vivo breast, the tissue types were mapped to variations in sound speed and acoustic absorption. Calculations of acoustic scattering by the resulting model were performed on massively parallel supercomputer clusters using parallel implementations of the k-space method and the fast multipole method. The efficient use of these resources was confirmed by parallel efficiency and scalability studies using large-scale, realistic tissue models. Comparisons between the temporal and spectral results were performed in representative planes by Fourier transforming the temporal results. An RMS field error less than 3% throughout the model volume confirms the accuracy of the methods for modeling ultrasound propagation through human breast. PMID:25096103

  12. In vivo bioluminescence imaging of magnetically targeted bone marrow-derived mesenchymal stem cells in skeletal muscle injury model.

    PubMed

    Nakabayashi, Akihiro; Kamei, Naosuke; Sunagawa, Toru; Suzuki, Osami; Ohkawa, Shingo; Kodama, Akira; Kamei, Goki; Ochi, Mitsuo

    2013-05-01

    The purpose of this study is to clarify the kinetics of transplanted mesenchymal stem cells (MSCs) in rat skeletal muscle injury model and the contribution of the magnetic cell delivery system to muscle injury repair. A magnetic field generator was used to apply an external magnetic force to the injury site of the tibia anterior muscle, and 1?×?10(6) MSCs labeled with ferucarbotran-protamine complexes, which were isolated from luciferase transgenic rats, were injected into the injury site. MSCs were injected with and without an external magnetic force (MSC M+ and MSC M- groups, respectively), and phosphate-buffered saline was injected into injury sites as a control. In vivo bioluminescence imaging was performed immediately after the transplantation and, at 12, 24, and 72?h, and 1 and 4 weeks post-transplantation. Also, muscle regeneration and function were histologically and electromechanically evaluated. In vivo bioluminescence imaging showed that the photon of the MSC M+ group was significantly higher than that of the MSC M- group throughout the observation period. In addition, muscle regeneration and function in the MSC M+ group was histologically and functionally better than that of the MSC M- group. The results of our study indicated that magnetic cell delivery system may be of use in directing the transplanted MSCs to the injury site to promote skeletal muscle regeneration. PMID:23192745

  13. The derivation and verification of surface reflectances using airborne MSS data and a radiative transfer model

    SciTech Connect

    Ramsey, E.W. III; Jensen, J.R.

    1988-01-01

    Surface reflectance images were derived from airborne MSS data using a radiative transfer model to eliminate atmospheric effects and to derive downwelling irradiances. Input radiative transfer model parameters and Brightness Value (BV) to radiance conversion gain and bias factors were generated for each band using an optimization procedure to minimize the difference between modelled and image BV. Subsequently, reflectance images were derived at five wavelengths from the blue to red bands using the optimized parameters as inputs into the radiative transfer model. Modelled surface reflectance images were evaluated for accuracy by statistical comparison to measured reflectances, and for improved contrast by subjective comparison to the original images. Daedalus DS-1260 MSS bands 3, 4 and 5 modelled reflectances explained 25%, 75% and 72% of the measured reflectance variances, respectively; while bands 2 and 7 correlation were not significant (p < .05). Finally, the generated reflectance images showed dramatic improvement in contrast, revealing textures that were not apparent in the original images. 20 refs., 4 figs., 3 tabs.

  14. Scene kinetics mitigation using factor analysis with derivative factors.

    SciTech Connect

    Larson, Kurt W.; Melgaard, David Kennett; Scholand, Andrew Joseph

    2010-07-01

    Line of sight jitter in staring sensor data combined with scene information can obscure critical information for change analysis or target detection. Consequently before the data analysis, the jitter effects must be significantly reduced. Conventional principal component analysis (PCA) has been used to obtain basis vectors for background estimation; however PCA requires image frames that contain the jitter variation that is to be modeled. Since jitter is usually chaotic and asymmetric, a data set containing all the variation without the changes to be detected is typically not available. An alternative approach, Scene Kinetics Mitigation, first obtains an image of the scene. Then it computes derivatives of that image in the horizontal and vertical directions. The basis set for estimation of the background and the jitter consists of the image and its derivative factors. This approach has several advantages including: (1) only a small number of images are required to develop the model, (2) the model can estimate backgrounds with jitter different from the input training images, (3) the method is particularly effective for sub-pixel jitter, and (4) the model can be developed from images before the change detection process. In addition the scores from projecting the factors on the background provide estimates of the jitter magnitude and direction for registration of the images. In this paper we will present a discussion of the theoretical basis for this technique, provide examples of its application, and discuss its limitations.

  15. LAT1 targeted delivery of methionine based imaging probe derived from M(III) metal ions for early diagnosis of proliferating tumours using molecular imaging modalities.

    PubMed

    Hazari, Puja Panwar; Prakash, Surbhi; Meena, Virendra K; Jaswal, Ambika; Khurana, Harleen; Mishra, Surabhi Kirti; Bhonsle, Hemanth Kumar; Singh, Lokendra; Mishra, Anil K

    2015-01-01

    We investigated the potential of DTPA-bis(Methionine), a target specific amino acid based probe for detection of L-type amino acid transporters (LAT1) known to over express in proliferating tumours using multimodality imaging. The ligand, DTPA-bis(Met) was readily converted to lanthanide complexes and was found capable of targeting cancer cells using multimodality imaging. DTPA-bis(Met) complexes were synthesized and characterized by mass spectroscopy. MR longitudinal relaxivity, r(1) = 4.067 ± 0.31 mM(-1) s(-1) and transverse relaxivity, r(2) = 8.61 ± 0.07 mM(-1) s(-1)of Gd(III)-DTPA-bis(Met) were observed at pH 7.4 at 7 T. Bright, localized fluorescence of Eu(III)-DTPA-bis(Met) was observed with standard microscopy and displacement studies indicated ligand functionality. K(D) value determined for Eu(III)-DTPA-bis(Met) on U-87 MG cells was found to be 17.3 pM and showed appreciable fluorescence within the cells. Radio HPLC showed a radiochemical purity more than 95% (specific activity = 400-500 MBq/?mol, labelling efficiency 78 %) for (68)Ga(III)-DTPA-bis(Met). Pre-treatment of xenografted U-87 MG athymic mice with (68)Ga(III)-DTPA-bis(Met) following unlabelled L-methionine administration reduced tumour uptake by 10-folds in Micro PET. These data support the specific binding of (68)Ga(III)-DTPA-bis(Met) to the LAT1 transporter. To summarize, this agent possesses high stability in biological environment and exhibits effective interaction with its LAT1 transporters giving high accumulation in tumour area, excellent tumour/non-tumour ratio and low non-specific retention in vivo. PMID:25329672

  16. Input modeling: input modeling techniques for discrete-event simulations

    Microsoft Academic Search

    Lawrence Leemis

    2001-01-01

    Most discrete-event simulation models have stochastic elements that mimic the probabilistic nature of the system under consideration. A close match between the input model and the true underlying probabilistic mechanism associated with the system is required for successful input modeling. The general question considered here is how to model an element (e.g., arrival process, service times) in a discrete-event simulation

  17. Unsupervised Image Translation

    Microsoft Academic Search

    Rómer Rosales; Kannan Achan; Brendan J. Frey

    2003-01-01

    An interesting and potentially useful vision\\/graphics task is to render an input image in an enhanced form or also in an unusual style; for example with increased sharpness or with some artistic qualities. In previous work (10, 5), researchers showed that by estimating the mapping from an input image to a registered (aligned) image of the same scene in a

  18. Validation of a paleo river system derived by ground based electromagnetic induction measurements with satellite based RapidEye images

    NASA Astrophysics Data System (ADS)

    Rudolph, Sebastian; von Hebel, Christian; Ali, Mohammed; Stadler, Anja; Herbst, Michael; Montzka, Carsten; Pätzold, Stefan; Weihermüller, Lutz; van der Kruk, Jan; Vereecken, Harry

    2013-04-01

    Morphological remnants of an inactive river system that has been filled by younger sediments can provide datable proxies about past climatic conditions. However, sediment composition of their infillings is a challenge for agriculture, in particular for precision agriculture. Differential crop development and yield reduction are often a consequence of lateral and vertical textural inhomogeneities. Several studies have shown that buried river systems can be traced by the use of remote sensing. However, the appearance of crop marks strongly depends on environmental conditions, and therefore, the reliance of remotely acquired data can become time and cost expensive. Soil physical properties which are related to textural differences can be mapped fast and cost-effective by the use of near surface geophysics. Especially electromagnetic induction (EMI), which measures soil apparent conductivity (ECa), has become a tool of choice to characterize large areas in high resolution. The introduction of multiple coil EMI systems as well as the quantification of respective measurements enables a reliable multilayer inversion. The aim of this study was to map a postglacial river system on agricultural fields and to mark out buried remains such as trenches and bomb craters of World War II. In summer 2012 ten fields (17 ha) were mapped with the CMD MiniExplorer, a multiple coil EMI system especially appropriate for near surface applications, after the harvest of winter wheat and sugar beet. At elevated sandy sites meander like patterns with higher conductivity were mapped. ECa measurements were verified by textural data taken from directed soil samples and vertical ECa logs. Sediment thickness was evaluated on soil cores and electrical resistivity tomography (ERT) transects. Furthermore, ERT quantified ECa measurements were correlated with satellite as well as destructive derived leaf area index (LAI) measurements. In 3 of 71 LAI maps derived by multispectral RapidEye imagery crop marks were clearly visible following a dry season in spring 2011. These patterns are in coincidence with higher conductivity patterns caused by a higher amount of silt and clay. Good correlations were found for LAI measurements taken during a growing season with underlying sediments especially in the early stages of plant development. Finally, ECa measurements of two heterogeneous fields were used for a 3D layer inversion which will be further implemented into landscape models. This study shows that multiple EMI measurements can be successfully used to recover buried river systems, highlight possible sample locations and support farmers to manage their fields more precisely.

  19. Cyclometalated iridium(III) complexes with imidazo[4,5-f][1,10]phenanthroline derivatives for mitochondrial imaging in living cells.

    PubMed

    Jin, Chengzhi; Liu, Jiangping; Chen, Yu; Li, Guanying; Guan, Ruilin; Zhang, Pingyu; Ji, Liangnian; Chao, Hui

    2015-04-28

    A new series of cyclometalated iridium(III) complexes with imidazo[4,5-f][1,10]phenanthroline derivatives (i.e., MitoIr1-MitoIr7) were synthesized and developed to image mitochondria in living cells. In comparison with commercially available mitochondrial trackers, these complexes exhibit a superior capacity to selectively accumulate in mitochondria with no requirement of any membrane permeabilization or replacement of the culture medium. In addition, the excellent photostability under continuous laser irradiation as well as the stable physiological pH resistance of these complexes were confirmed by photobleaching experiments and luminescence measurements. Importantly, MitoIr7, which exhibited both excellent luminescence and high ability to locate in mitochondria, was developed to track the mitochondrial morphological changes over a long period of time. PMID:25805054

  20. Hemodynamic assessment of partial mechanical circulatory support: data derived from computed tomography angiographic images and computational fluid dynamics.

    PubMed

    Karmonik, Christof; Partovi, Sasan; Rengier, Fabian; Meredig, Hagen; Farag, Mina Berty; Müller-Eschner, Matthias; Arif, Rawa; Popov, Aron-Frederik; Kauczor, Hans-Ulrich; Karck, Matthias; Ruhparwar, Arjang

    2015-04-01

    Partial mechanical circulatory support represents a new concept for the treatment of advanced heart failure. The Circulite Synergy Micro Pump(®), where the inflow cannula is connected to the left atrium and the outflow cannula to the right subclavian artery, was one of the first devices to introduce this concept to the clinic. Using computational fluid dynamics (CFD) simulations, hemodynamics in the aortic tree was visualized and quantified from computed tomography angiographic (CTA) images in two patients. A realistic computational model was created by integrating flow information from the native heart and from the Circulite device. Diastolic flow augmentation in the descending aorta but competing/antagonizing flow patterns in the proximal innominate artery was observed. Velocity time curves in the ascending aorta correlated well with those in the left common carotid, the left subclavian and the descending aorta but poorly with the one in the innominate. Our results demonstrate that CFD may be useful in providing a better understanding of the main flow patterns in mechanical circulatory support devices. PMID:25984458

  1. Hemodynamic assessment of partial mechanical circulatory support: data derived from computed tomography angiographic images and computational fluid dynamics

    PubMed Central

    Karmonik, Christof; Rengier, Fabian; Meredig, Hagen; Farag, Mina Berty; Müller-Eschner, Matthias; Arif, Rawa; Popov, Aron-Frederik; Kauczor, Hans-Ulrich; Karck, Matthias; Ruhparwar, Arjang

    2015-01-01

    Partial mechanical circulatory support represents a new concept for the treatment of advanced heart failure. The Circulite Synergy Micro Pump®, where the inflow cannula is connected to the left atrium and the outflow cannula to the right subclavian artery, was one of the first devices to introduce this concept to the clinic. Using computational fluid dynamics (CFD) simulations, hemodynamics in the aortic tree was visualized and quantified from computed tomography angiographic (CTA) images in two patients. A realistic computational model was created by integrating flow information from the native heart and from the Circulite device. Diastolic flow augmentation in the descending aorta but competing/antagonizing flow patterns in the proximal innominate artery was observed. Velocity time curves in the ascending aorta correlated well with those in the left common carotid, the left subclavian and the descending aorta but poorly with the one in the innominate. Our results demonstrate that CFD may be useful in providing a better understanding of the main flow patterns in mechanical circulatory support devices. PMID:25984458

  2. Synthesis, 18F-Radiolabelling and Biological Characterization of Novel Fluoroalkylated Triazine Derivatives for in Vivo Imaging of Phosphodiesterase 2A in Brain via Positron Emission Tomography.

    PubMed

    Schröder, Susann; Wenzel, Barbara; Deuther-Conrad, Winnie; Teodoro, Rodrigo; Egerland, Ute; Kranz, Mathias; Scheunemann, Matthias; Höfgen, Norbert; Steinbach, Jörg; Brust, Peter

    2015-01-01

    Phosphodiesterase 2A (PDE2A) is highly and specifically expressed in particular brain regions that are affected by neurological disorders and in certain tumors. Development of a specific PDE2A radioligand would enable molecular imaging of the PDE2A protein via positron emission tomography (PET). Herein we report on the syntheses of three novel fluoroalkylated triazine derivatives (TA2-4) and on the evaluation of their effect on the enzymatic activity of human PDE2A. The most potent PDE2A inhibitors were 18F-radiolabelled ([18F]TA3 and [18F]TA4) and investigated regarding their potential as PET radioligands for imaging of PDE2A in mouse brain. In vitro autoradiography on rat brain displayed region-specific distribution of [18F]TA3 and [18F]TA4, which is consistent with the expression pattern of PDE2A protein. Metabolism studies of both [18F]TA3 and [18F]TA4 in mice showed a significant accumulation of two major radiometabolites of each radioligand in brain as investigated by micellar radio-chromatography. Small-animal PET/MR studies in mice using [18F]TA3 revealed a constantly increasing uptake of activity in the non-target region cerebellum, which may be caused by the accumulation of brain penetrating radiometabolites. Hence, [18F]TA3 and [18F]TA4 are exclusively suitable for in vitro investigation of PDE2A. Nevertheless, further structural modification of these promising radioligands might result in metabolically stable derivatives. PMID:26016549

  3. Intravital and Whole-Organ Imaging Reveals Capture of Melanoma-Derived Antigen by Lymph Node Subcapsular Macrophages Leading to Widespread Deposition on Follicular Dendritic Cells

    PubMed Central

    Moalli, Federica; Proulx, Steven T.; Schwendener, Reto; Detmar, Michael; Schlapbach, Christoph; Stein, Jens V.

    2015-01-01

    Aberrant antigens expressed by tumor cells, such as in melanoma, are often associated with humoral immune responses, which may in turn influence tumor progression. Despite recent data showing the central role of adaptive immune responses on cancer spread or control, it remains poorly understood where and how tumor-derived antigen (TDA) induces a humoral immune response in tumor-bearing hosts. Based on our observation of TDA accumulation in B cell areas of lymph nodes (LNs) from melanoma patients, we developed a pre-metastatic B16.F10 melanoma model expressing a fluorescent fusion protein, tandem dimer tomato, as a surrogate TDA. Using intravital two-photon microscopy (2PM) and whole-mount 3D LN imaging of tumor-draining LNs in immunocompetent mice, we report an unexpectedly widespread accumulation of TDA on follicular dendritic cells (FDCs), which were dynamically scanned by circulating B cells. Furthermore, 2PM imaging identified macrophages located in the subcapsular sinus of tumor-draining LNs to capture subcellular TDA-containing particles arriving in afferent lymph. As a consequence, depletion of macrophages or genetic ablation of B cells and FDCs resulted in dramatically reduced TDA capture in tumor-draining LNs. In sum, we identified a major pathway for the induction of humoral responses in a melanoma model, which may be exploitable to manipulate anti-TDA antibody production during cancer immunotherapy. PMID:25821451

  4. A 18F-labeled saxitoxin derivative for in vivo PET-MR imaging of voltage-gated sodium channel expression following nerve injury.

    PubMed

    Hoehne, Aileen; Behera, Deepak; Parsons, William H; James, Michelle L; Shen, Bin; Borgohain, Preeti; Bodapati, Deepika; Prabhakar, Archana; Gambhir, Sanjiv S; Yeomans, David C; Biswal, Sandip; Chin, Frederick T; Du Bois, J

    2013-12-01

    Both chronic and neuropathic pain conditions are associated with increased expression of certain voltage-gated sodium ion channel (NaV) isoforms in peripheral sensory neurons. A method for noninvasive imaging of these channels could represent a powerful tool for investigating aberrant expression of NaV and its role in pain pathogenesis. Herein, we describe the synthesis and evaluation of a positron emission tomography (PET) radiotracer targeting NaVs, the design of which is based on the potent, NaV-selective inhibitor saxitoxin. Both autoradiography analysis of sciatic nerves excised from injured rats as well as whole animal PET-MR imaging demonstrate that a systemically administered [(18)F]-labeled saxitoxin derivative concentrates at the site of nerve injury, consistent with upregulated sodium channel expression following axotomy. This type of PET agent has potential use for serial monitoring of channel expression levels at injured nerves throughout wound healing and/or following drug treatment. Such information may be correlated with pain behavioral analyses to help shed light on the complex molecular processes that underlie pain sensation. PMID:24261833

  5. Patch-Clamp Recordings and Calcium Imaging Followed by Single-Cell PCR Reveal the Developmental Profile of 13 Genes in iPSC-Derived Human Neurons

    PubMed Central

    Belinsky, Glenn S.; Rich, Matthew T.; Sirois, Carissa L.; Short, Shaina M.; Pedrosa, Erika; Lachman, Herbert M.; Antic, Srdjan D.

    2013-01-01

    Molecular genetic studies are typically performed on homogenized biological samples, resulting in contamination from non-neuronal cells. To improve expression profiling of neurons we combined patch recordings with single-cell PCR. Two iPSC lines (healthy subject and 22q11.2 deletion), were differentiated into neurons. Patch electrode recordings were performed on 229 human cells from Day-13 to Day-88, followed by capture and single-cell PCR for 13 genes: ACTB, HPRT, vGLUT1, ?TUBIII, COMT, DISC1, GAD1, PAX6, DTNBP1, ERBB4, FOXP1, FOXP2, and GIRK2. Neurons derived from both iPSC lines expressed ?TUBIII, fired action potentials, and experienced spontaneous depolarizations (UP states) ~2 weeks before vGLUT1, GAD1 and GIRK2 appeared. Multisite calcium imaging revealed that these UP states were not synchronized among hESC-H9-derived neurons. The expression of FOXP1, FOXP2 and vGLUT1 was lost after 50 days in culture, in contrast to other continuously expressed genes. When gene expression was combined with electrophysiology, two subsets of genes were apparent; those irrelevant to spontaneous depolarizations (including vGLUT1, GIRK2, FOXP2 and DISC1) and those associated with spontaneous depolarizations (GAD1 and ERBB4). The results demonstrate that in the earliest stages of neuron development, it is useful to combine genetic analysis with physiological characterizations, on a cell-to-cell basis. PMID:24157591

  6. Inner Heliospheric Evolution of a 'Stealth' CME Derived From Multi-view Imaging and Multipoint In-situ observations

    NASA Astrophysics Data System (ADS)

    Nieves-Chinchilla, T.; Vourlidas, A.; Stenborg, G.; Savani, N.; Koval, A.; Szabo, A.; Jian, L.; Hidalgo, M.; Lepping, R. P.

    2013-12-01

    Coronal mass ejections (CMEs) are the main driver of Space Weather. Therefore, a precise forecasting of their likely geo-effectiveness relies on an accurate tracking of their morphological and kinematical evolution throughout the interplanetary medium. However, single view-point observations require many assumptions to model the development of the features of CMEs. Before of the STEREO mission, the most common hypotheses were those of radial propagation and self-similar expansion. The use of different view-points shows that at least for some cases, those assumptions are no longer valid. Typical attributes that can now been confirmed to exist are departures from radial propagation, over-expansion, and rotation along the propagation axis. Understanding of the 3D development and evolution of the CME features is therefore of utmost importance to help establish the connection between remote and in-situ observations, and hence help forecast Space Weather. We present on analysis of the morphological and kinematical evolution of a STEREO B-directed CME on 2009 August 25-27. By means of a comprehensive analysis of remote imaging observations provided by SOHO, STEREO and SDO missions, and in-situ measurements recorded by Wind, ACE, and Messenger, we prove in this paper that the event exhibits signatures of rotation, changes in the direction of propagation, and/or interaction with other magnetic obstacles. We propose a method to investigate the change of the CME Tilt from the analysis of Height-Time measurements and we found that the results are consistent with in-situ reconstructions and solar source analysis. If this result is validated in further work, it may have important implications for space weather studies and new generation of inner heliospheric missions because it will allow us to infer the ICME orientation at 1 AU using remote sensing observations of the first stages of the CME.

  7. Impact of metal binding on the antitumor activity and cellular imaging of a metal chelator cationic imidazopyridine derivative.

    PubMed

    Roy, Mithun; Chakravarthi, Balabhadrapatruni V S K; Jayabaskaran, Chelliah; Karande, Anjali A; Chakravarty, Akhil R

    2011-05-14

    A new water soluble cationic imidazopyridine species, viz. (1E)-1-((pyridin-2-yl)methyleneamino)-3-(3-(pyridin-2-yl)imidazo[1,5-a]pyridin-2(3H)-yl)propan-2-ol (1), as a metal chelator is prepared as its PF(6) salt and characterized. Compound 1 shows fluorescence at 438 nm on excitation at 342 nm in Tris-HCl buffer giving a fluorescence quantum yield (?) of 0.105 and a life-time of 5.4 ns. Compound 1, as an avid DNA minor groove binder, shows pUC19 DNA cleavage activity in UV-A light of 365 nm forming singlet oxygen species in a type-II pathway. The photonuclease potential of 1 gets enhanced in the presence of Fe(2+), Cu(2+) or Zn(2+). Compound 1 itself displays anticancer activity in HeLa, HepG2 and Jurkat cells with an enhancement on addition of the metal ions. Photodynamic effect of 1 at 365 nm also gets enhanced in the presence of Fe(2+) and Zn(2+). Fluorescence-based cell cycle analysis shows a significant dead cell population in the sub-G1 phase of the cell cycle suggesting apoptosis via ROS generation. A significant change in the nuclear morphology is observed from Hoechst 33258 and an acridine orange/ethidium bromide (AO/EB) dual nuclear staining suggesting apoptosis in cells when treated with 1 alone or in the presence of the metal ions. Apoptosis is found to be caspase-dependent. Fluorescence imaging to monitor the distribution of 1 in cells shows that 1 in the presence of metal ions accumulates predominantly in the cytoplasm. Enhanced uptake of 1 into the cells within 12 h is observed in the presence of Fe(2+) and Zn(2+). PMID:21431236

  8. Last developments of the EUMETSAT Atmospheric Motion Vector product derived from MSG images for assimilation in NWP models

    NASA Astrophysics Data System (ADS)

    Borde, Regis; Bertil Gustafsson, Jörgen; de Smet, Arthur; Dew, Greg

    2010-05-01

    Atmospheric Motion Vectors (AMVs) are one of the most important products derived from all geostationary satellites, because they constitute a very important part of the observation data provided to Numerical Weather Prediction models. The Height Assignment (HA) is currently the most difficult task in the AMV extraction scheme. Several sources of error can be introduced at the height assignment step, but one of the main difficulties is to clearly identify the pixels that lead the tracking process in the tracer box, in order to select them for the HA calculation. A good pixel selection process should ensure to keep a direct link between the feature really tracked and the calculation of the height. The most common method sorts the coldest pixels in the target box and uses them to calculate the AMV height. However, recent work showed that some of the coldest pixels can have very small and/or negative contribution to the cross correlation process. Following these findings, it is then proposed to use individual pixel contribution to the cross correlation coefficient information in the pixel selection process, in order to get a closer link between the tracked feature tracked and the HA. This method has been tested on a parallel chain at EUMETSAT for two separated periods of one month. This presentation summarizes the main results of these operational tests, which show some improvements of the new scheme on the AMV product for both the VIS0.8, HRV and IR10.8 channels, increasing the total amount of good AMVs (Quality Index QI>80) and also the amount of good AMV/radiosonde collocations. Speed biases and RMS against radiosonde observations are generally a bit larger, especially the known slow bias observed at high levels for IR10.8 AMVs, but are calculated on a bigger amount of data.

  9. Region-based image fusion method using bidimensional empirical mode decomposition

    NASA Astrophysics Data System (ADS)

    Zheng, Youzhi; Qin, Zheng

    2009-01-01

    We propose a novel multiscale decomposition (MSD) image fusion algorithm, which is region-based image fusion using bidimensional empirical mode decomposition (BEMD). BEMD is a 2-D data-driven decomposition derived from the empirical mode decomposition (EMD), which does not require predetermined filter or wavelet function. The input images are decomposed into a number of intrinsic mode functions (IMFs) as well as a residual image. The fusion is performed region by region based on the segmentations of the input images to produce composite BEMD representation, and then the inverse BEMD transform is applied to obtain the fused image. Experiments show that the proposed image fusion algorithm provides superior performance over traditional fusion schemes in terms of both objective metrics and visual quality.

  10. Technetium-99m-human polyclonal IgG radiolabeled via the hydrazino nicotinamide derivative for imaging focal sites of infection in rats

    SciTech Connect

    Abrams, M.J.; Juweid, M.; tenKate, C.I.; Schwartz, D.A.; Hauser, M.M.; Gaul, F.E.; Fuccello, A.J.; Rubin, R.H.; Strauss, H.W.; Fischman, A.J. (Massachusetts General Hospital, Boston (USA))

    1990-12-01

    The biologic behavior of human polyclonal immunoglobulin (IgG) radiolabeled with technetium-99m ({sup 99m}Tc) by a novel method, via a nicotinyl hydrazine derivative, was evaluated in rats. Technetium-99m- and indium-111-IgG were co-administered to normal rats and biodistribution was determined at 2, 6, and 16 hr. The inflammation imaging properties of the two reagents were compared in rats with deep-thigh infection due to Escherichia coli. Blood clearance of both antibody preparations was well described by a bi-exponential function: ({sup 99m}Tc-IgG: t1/2 = 3.82 +/- 0.89 and 57.52 +/- 1.70 hr. {sup 111}In-IgG: 3.93 +/- 0.117 and 40.71 +/- 1.26 hr). Biodistributions in the solid organs were similar, however, small but statistically significant differences were detected: {sup 99m}Tc-IgG greater than {sup 111}In-IgG in lung, liver, and spleen; {sup 99m}Tc-IgG less than {sup 111}In-IgG in kidney and skeletal muscle (p less than 0.01). At all three imaging times, target-to-background ratio and percent residual activity for the two compounds were remarkably similar. These studies establish that human polyclonal IgG labeled with {sup 99m}Tc via a nicotinyl hydrazine modified intermediate is equivalent to {sup 111}In-IgG for imaging focal sites of infection in experimental animals.

  11. Present State of the Long Valley Caldera/California Derived From DC-Resistivity Imaging and Self-Potential Measurements

    NASA Astrophysics Data System (ADS)

    Flechsig, C.; Schuetze, C.; Jacobs, F.; Serfling, U.

    2001-12-01

    The geoelectrical methods make sense to apply in volcanic areas since porosity, permeability, ionic mobility, ionic concentration in rock fluids, and cation exchange capability are modified by volcanic - magmatic activity directly and processes generated by volcanism (geothermal systems). Resistivity of volcanic rocks is a meaningful indicator for changes in porosity and ionic mobility, ionic concentrations in fluids, mobility of fluids caused by changes in temperature. A large-scale Direct-Current (DC) imaging investigation of the Long Valley system included both an active 21 km DC-survey line across the caldera and the mapping of natural self-potential (SP) anomalies in the western and central part. The deep sounding Electrical Resistivity Tomography (ERT) was applied successfully. The 21 km long dipole-dipole profile in east-west direction according to Wannamaker et al. (1991) was selected deliberately in order to compare the results. For the detection of the potential differences special stand alone transient recorders were applied. This kind of signal recording offers the possibility of statistical methods for signal enhancement. The recorded time series yield information not only about the DC-resistivity than special effects like induced polarization events and self-potentials. The first application of tomographic resistivity sounding in Long Valley is resulting in a recent 2-D model of resistivity distribution in subsurface after the resurgence of volcanic activity in the 80ies. The inversion result reveals numerous resistivity structures which are in very good correlation with known geologic and tectonic structures. The tomographical inversion of DC-data was carried out with the goal to study the geological structures of the Long Valley Caldera down to 3-4 km, especially in the part affected by the resurgent dome and the hydrothermal system by use of geoelectrical parameters. The important structural components include low-resistivity regions beneath the western half of caldera, which are originated by the shallow hydrothermal system. A large conductive segment under the Medial Graben, already described by Wannamaker et al. (1991), can also be seen, whereas the majority of resurgent dome appears highly resistive. The interpretation of the resistivity model is sustained by self-potential anomalies, measured in the western part of caldera, by the comparison with known fault zones and by implications for fluid flow inferred from geothermal data, whereupon the resurgent dome is not influenced by the present hydrothermal fluid flow.

  12. Assessment of urban tree growth from structure, nutrients and composition data derived from airborne lidar and imaging spectroscopy

    NASA Astrophysics Data System (ADS)

    Gu, H.; Townsend, P. A.; Singh, A.

    2014-12-01

    Urban forests provide important ecosystem services related to climate, nutrients, runoff and aesthetics. Assessment of variations in urban forest growth is critical to urban management and planning, as well as to identify responses to climate and other environmental changes. We estimated annual relative basal area increment by tree rings from 37 plots in Madison, Wisconsin and neighboring municipalities. We related relative basal area growth to variables of vegetation traits derived from remote sensing, including structure (aboveground biomass, diameter, height, basal area, crown width and crown length) from discrete-return airborne lidar, and biochemical variables (foliar nitrogen, carbon, lignin, cellulose, fiber and LMA), spectral indices (NDVI, NDWI, PRI, NDII etc.) and species composition from AVIRIS hyperspectral imagery. Variations in tree growth was mainly correlated with tree species composition (R2 = 0.29, RMSE = 0.004) with coniferous stands having a faster growth rate than broadleaf plots. Inclusion of stand basal area improved model prediction from R2 = 0.29 to 0.35, with RMSE = 0.003. Then, we assessed the growth by functional type, we found that foliar lignin concentration and the proportion of live coniferous trees explained 57% variance in the growth of conifer stands. In contrast, broadleaf forest growth was more strongly correlated with species composition and foliar carbon (R2 = 0.59, RMSE = 0.003). Finally, we compared the relative basal area growth by species. In our study area, red pine and white pine exhibited higher growth rates than other species, while white oak plots grew slowest. There is a significant negative relationship between tree height and the relative growth in red pine stands (r = -0.95), as well as a strong negative relationship between crown width and the relative growth in white pine stands (r = -0.87). Growth declines as trees grow taller and wider may partly be the result of reduced photosynthesis and water availability. We also found that canopy cellulose content was negatively correlated with growth in white oak (r = -0.59), which could be caused by trade off of carbon allocation from shoot storage to leaves. These results demonstrate the potential of lidar and hyperspectral imagery to characterize important traits associated with biomass accumulation in urban forests.

  13. Dynamic Susceptibility Contrast MRI with Localized Arterial Input Functions

    PubMed Central

    Lee, J.J.; Bretthorst, G.L.; Derdeyn, C.P.; Powers, W.J.; Videen, T.O.; Snyder, A.Z.; Markham, J.; Shimony, J.S.

    2010-01-01

    Compared to gold-standard measurements of cerebral perfusion with positron emission tomography (PET) using H2[15O] tracers, measurements with dynamic susceptibility contrast (DSC) MR are more accessible, less expensive and less invasive. However, existing methods for analyzing and interpreting data from DSC MR have characteristic disadvantages that include sensitivity to incorrectly modeled delay and dispersion in a single, global arterial input function (AIF). We describe a model of tissue microcirculation derived from tracer kinetics which estimates for each voxel a unique, localized AIF (LAIF). Parameters of the model were estimated using Bayesian probability theory and Markov-chain Monte Carlo, circumventing difficulties arising from numerical deconvolution. Applying the new method to imaging studies from a cohort of fourteen patients with chronic, atherosclerotic, occlusive disease showed strong correlations between perfusion measured by DSC MR with LAIF and perfusion measured by quantitative PET with H2[15O]. Regression to PET measurements enabled conversion of DSC MR to a physiological scale. Regression analysis for LAIF gave estimates of a scaling factor for quantitation which described perfusion accurately in patients with substantial variability in hemodynamic impairment. PMID:20432301

  14. Inverting input scanner vibration errors

    Microsoft Academic Search

    George Wolberg; Robert C. Loce

    1995-01-01

    Images scanned in the presence of mechanical vibrations are subject to artifacts such as brightness fluctuation and geometric warping. The goal of this work is to develop an algorithm to invert these distortions and produce an output digital image consistent with a scanner operating under ideal uniform motion conditions. The image restoration algorithm described in this paper applies to typical

  15. Fundamentals of! Image Processing!

    E-print Network

    Erdem, Erkut

    can F hold both? Complex number trick! )()()( iIRF += 22 )()( IRA +±= )( )( tan 1 R I- = We can Correlation! Slide: Hoiem! Matching with filters" · Goal: find in image! · Method 0: filter the image with eye: find in image! · Method 1: filter the image with zero-mean eye! ! Input! Filtered Image (scaled

  16. Fundamentals of Image Processing

    E-print Network

    Erdem, Erkut

    can F hold both? Complex number trick! )()()( iIRF += 22 )()( IRA +±= )( )( tan 1 R I- = We can Slide: Hoiem #12;Matching with filters · Goal: find in image · Method 0: filter the image with eye: find in image · Method 1: filter the image with zero-mean eye Input Filtered Image (scaled

  17. Mass Exchange Processes with Input

    E-print Network

    P. L. Krapivsky

    2015-03-07

    We investigate a system of interacting clusters evolving through mass exchange and supplemented by input of small clusters. Three possibilities depending on the rate of exchange generically occur when input is homogeneous: continuous growth, gelation, and instantaneous gelation. We mostly study the growth regime using scaling methods. An exchange process with reaction rates equal to the product of reactant masses admits an exact solution which allows us to justify the validity of scaling approaches in this special case. We also investigate exchange processes with a localized input. We show that if the diffusion coefficients are mass-independent, the cluster mass distribution becomes stationary and develops an algebraic tail far away from the source.

  18. Inverting Amplifier with Current Input

    NSDL National Science Digital Library

    This animated gif illustrates the changing voltages a conventional inverting amplifier when it receives input from a current source rather than a voltage source. Notice that the input resistor does not offer any impedance. Voltages and parts of the circuit of this 3-D animated gif are highlighted with different colors. Current is displayed by green arrows indicating directional flow. The animation requires a Web browser or other video player software capable of displaying gif animations.Other 3-D Circuit Animations can be seen here.

  19. Optimal control of chaotic systems with input saturation using an input-state linearization scheme

    NASA Astrophysics Data System (ADS)

    Fuh, Chyun-Chau

    2009-08-01

    Chaos is undesirable in many engineering applications since it causes a serious degradation of the system performance and restricts the system's operating range. Therefore, the problem of controlling chaos has attracted intense interest in recent years. This paper proposes an approach for optimizing the control of chaotic systems with input saturation using an input-state linearization scheme. In the proposed approach, the optimal system gains are identified using the Nelder-Mead simplex algorithm. This algorithm does not require the derivatives of the cost function (or the performance index) to be optimized, and is therefore particularly applicable to problems with undifferentiable elements or discontinuities. Two numerical simulations are performed to demonstrate the feasibility and effectiveness of the proposed method.

  20. Input classes for identifiability of bilinear systems

    E-print Network

    Sontag, Eduardo D.

    This paper asks what classes of input signals are sufficient in order to completely identify the input/output behavior of generic bilinear systems. The main results are that step inputs are not sufficient, nor are single ...

  1. Systems and methods for reconfiguring input devices

    NASA Technical Reports Server (NTRS)

    Lancaster, Jeff (Inventor); De Mers, Robert E. (Inventor)

    2012-01-01

    A system includes an input device having first and second input members configured to be activated by a user. The input device is configured to generate activation signals associated with activation of the first and second input members, and each of the first and second input members are associated with an input function. A processor is coupled to the input device and configured to receive the activation signals. A memory coupled to the processor, and includes a reconfiguration module configured to store the input functions assigned to the first and second input members and, upon execution of the processor, to reconfigure the input functions assigned to the input members when the first input member is inoperable.

  2. EXE: automatically generating inputs of death

    Microsoft Academic Search

    Cristian Cadar; Vijay Ganesh; Peter M. Pawlowski; David L. Dill; Dawson R. Engler

    2006-01-01

    This paper presents EXE, an effective bug-finding tool that automatically generates inputs that crash real code. Instead of running code on manually or randomly constructed input, EXE runs it on symbolic input initially allowed to be \\

  3. Design of observers for linear systems with unknown inputs

    Microsoft Academic Search

    M. Hou; P. C. Muller

    1992-01-01

    With a straightforward treatment, a design of reduced-order observers is presented for linear systems with unknown inputs. The observers are derived with a physical meaning. Some explanations are given within the framework of descriptor system observer design principles. The conditions for the existence of the observers are presented. Some illustrative examples are included

  4. Global sensitivity analysis of computer models with functional inputs

    E-print Network

    Boyer, Edmond

    propose the use of the joint modeling approach, i.e., modeling simultaneously the mean and the dispersion the "dispersion model" allows to derive the total sensitivity index of the functional input variables fuel irradiation. Keywords: Sobol's indices, joint modeling, generalized additive model, metamodel

  5. Synthesis of a [2-pyridinyl-18F]-labelled fluoro derivative of (-)-cytisine as a candidate radioligand for brain nicotinic alpha4beta2 receptor imaging with PET.

    PubMed

    Roger, Gaëlle; Lagnel, Béatrice; Rouden, Jacques; Besret, Laurent; Valette, Héric; Demphel, Stéphane; Gopisetti, JaganMohan; Coulon, Christine; Ottaviani, Michele; Wrenn, Lori A; Letchworth, Sharon R; Bohme, Georg A; Benavides, Jesus; Lasne, Marie-Claire; Bottlaender, Michel; Dollé, Frédéric

    2003-12-01

    In recent years, there has been considerable effort to design and synthesize radiotracers suitable for use in Positron Emission Tomography (PET) imaging of the alpha4beta2 neuronal nicotinic acetylcholine receptor (nAChR) subtype. A new fluoropyridinyl derivative of (-)-cytisine (1), namely (-)-9-(2-fluoropyridinyl)cytisine (3, K(i) values of 24 and 3462 nM for the alpha4beta2 and alpha7 nAChRs subtypes, respectively) has been synthesized in four chemical steps from (-)-cytisine and labelled with fluorine-18 (T(1/2): 119.8 min) using an efficient two-step radiochemical process [(a). nucleophilic heteroaromatic ortho-radiofluorination using the corresponding N-Boc-protected nitro-derivative, (b). TFA removal of the Boc protective group]. Typically, 20-45 mCi (0.74-1.67 GBq) of (-)-9-(2-[18F]fluoropyridinyl)cytisine ([18F]-3, 2-3 Ci/micromol or 74-111 GBq/micromol) were easily obtained in 70-75 min starting from a 100 mCi (3.7 GBq) aliquot of a cyclotron-produced [18F]fluoride production batch (20-45% non decay-corrected yield based on the starting [18F]fluoride). The in vivo pharmacological profile of (-)-9-(2-[18F]fluoropyridinyl)cytisine ([18F]-3) was evaluated in rats with biodistribution studies and brain radioactivity monitoring using intracerebral radiosensitive beta-microprobes. The observed in vivo distribution of the radiotracer in brain was rather uniform, and did not match with the known regional densities of nAChRs. It was also significantly different from that of the parent compound (-)-[3H]cytisine. Moreover, competition studies with (-)-nicotine (5 mg/kg, 5 min before the radiotracer injection) did not reduce brain uptake of the radiotracer. These experiments clearly indicate that (-)-9-(2-[18F]fluoropyridinyl)cytisine ([18F]-3) does not have the required properties for imaging nAChRs using PET. PMID:14642577

  6. Image-Based Quantification of Benzoporphyrin Derivative Uptake, Localization, and Photobleaching in 3D Tumor Models, for Optimization of PDT Parameters

    PubMed Central

    Glidden, Michael D.; Celli, Jonathan P.; Massodi, Iqbal; Rizvi, Imran; Pogue, Brian W.; Hasan, Tayyaba

    2012-01-01

    Photodynamic therapy (PDT) is a light-based treatment modality in which wavelength specific activation of a photosensitizer (PS) generates cytotoxic response in the irradiated region. PDT response is critically dependent on several parameters including light dose, PS dose, uptake time, fluence rate, and the mode of light delivery. While the systematic optimization of these treatment parameters can be complex, it also provides multiple avenues for enhancement of PDT efficacy under diverse treatment conditions, provided that a rational framework is established to quantify the impact of parameter selection upon treatment response. Here we present a theranostic technique, combining the inherent ability of the PS to serve simultaneously as a therapeutic and imaging agent, with the use of image-based treatment assessment in three dimensional (3D) in vitro tumor models, to comprise a platform to evaluate the impact of PDT parameters on treatment outcomes. We use this approach to visualize and quantify the uptake, localization, and photobleaching of the PS benzoporphyrin derivative monoacid ring-A (BPD) in a range of treatment conditions with varying uptake times as well as continuous and fractionated light delivery regimens in 3D cultures of AsPC-1 and PANC-1 cells. Informed by photobleaching patterns and correlation with cytotoxic response, asymmetric fractionated light delivery at 4 hours BPD uptake was found to be the most effective regimen assessed. Quantification of the spatial profile of cell killing within multicellular nodules revealed that these conditions also achieve the highest depth of cytotoxicity along the radial axis of 3D nodules. The framework introduced here provides a means for systematic assessment of PDT treatment parameters in biologically relevant 3D tumor models with potential for broader application to other systems. PMID:23082096

  7. Consumer need for tactile input

    Microsoft Academic Search

    Alka Varma Citrin; Donald E. Stemsupbs; Eric R. Spangenberg; Michael J. Clark

    2003-01-01

    A shortcoming of Internet-based retailing efforts is consumers' inability to touch products during their purchase decision-making processes. This research is a preliminary effort to examine the construct of need for tactile input by consumers and its impact on the likelihood to purchase products over the Internet. Initial measurement of the construct is developed through a survey of 272 respondents. This

  8. The semantics of graphical input

    Microsoft Academic Search

    Ed Anson

    1979-01-01

    Any graphical input device may be represented by a data structure, modified from time to time by actions in response to certain events, and the ability to cause certain events as part of its repertoire of actions. Portions of a device's state may be made visible to other devices in a controlled way, and the remainder hidden. Conversely, a device

  9. Modeling Input Validation in UML

    Microsoft Academic Search

    Pedram Hayati; Nastaran Jafari; S. Mohammad Rezaei; Saeed Sarenche; Vidyasagar Potdar

    2008-01-01

    Abstract Security is an integral part of most,software systems but it is not considered ,as an ,explicit part in the development,process yet. Input validation is the most critical part of software security that is not covered in the design phase ,of software ,development ,life-cycle resulting,in many ,security ,vulnerabilities. Our

  10. Signal Prediction With Input Identification

    NASA Technical Reports Server (NTRS)

    Juang, Jer-Nan; Chen, Ya-Chin

    1999-01-01

    A novel coding technique is presented for signal prediction with applications including speech coding, system identification, and estimation of input excitation. The approach is based on the blind equalization method for speech signal processing in conjunction with the geometric subspace projection theory to formulate the basic prediction equation. The speech-coding problem is often divided into two parts, a linear prediction model and excitation input. The parameter coefficients of the linear predictor and the input excitation are solved simultaneously and recursively by a conventional recursive least-squares algorithm. The excitation input is computed by coding all possible outcomes into a binary codebook. The coefficients of the linear predictor and excitation, and the index of the codebook can then be used to represent the signal. In addition, a variable-frame concept is proposed to block the same excitation signal in sequence in order to reduce the storage size and increase the transmission rate. The results of this work can be easily extended to the problem of disturbance identification. The basic principles are outlined in this report and differences from other existing methods are discussed. Simulations are included to demonstrate the proposed method.

  11. SAM: an improved input device

    Microsoft Academic Search

    L. T. Hauck

    1992-01-01

    SAM allows people to communicate by sending Morse code with a single switch. Unlike most Morse code input devices, SAM allows extreme latitude in the timing of dots and dashes. This makes it usable by people who have trouble mastering the precise timing of conventional Morse code. SAM is portable and inexpensive-it costs about $50 to build and runs on

  12. Regional Hospital Input Price Indexes

    PubMed Central

    Freeland, Mark S.; Schendler, Carol Ellen; Anderson, Gerard

    1981-01-01

    This paper describes the development of regional hospital input price indexes that is consistent with the general methodology used for the National Hospital Input Price Index. The feasibility of developing regional indexes was investigated because individuals inquired whether different regions experienced different rates of increase in hospital input prices. The regional indexes incorporate variations in cost-share weights (the amount an expense category contributes to total spending) associated with hospital type and location, and variations in the rate of input price increases for various regions. We found that between 1972 and 1979 none of the regional price indexes increased at average annual rates significantly different from the national rate. For the more recent period 1977 through 1979, the increase in one Census Region was significantly below the national rate. Further analyses indicated that variations in cost-share weights for various types of hospitals produced no substantial variations in the regional price indexes relative to the national index. We consider these findings preliminary because of limitations in the availability of current, relevant, and reliable data, especially for local area wage rate increases. PMID:10309557

  13. Effects of control inputs on the estimation of stability and control parameters of a light airplane

    NASA Technical Reports Server (NTRS)

    Cannaday, R. L.; Suit, W. T.

    1977-01-01

    The maximum likelihood parameter estimation technique was used to determine the values of stability and control derivatives from flight test data for a low-wing, single-engine, light airplane. Several input forms were used during the tests to investigate the consistency of parameter estimates as it relates to inputs. These consistencies were compared by using the ensemble variance and estimated Cramer-Rao lower bound. In addition, the relationship between inputs and parameter correlations was investigated. Results from the stabilator inputs are inconclusive but the sequence of rudder input followed by aileron input or aileron followed by rudder gave more consistent estimates than did rudder or ailerons individually. Also, square-wave inputs appeared to provide slightly improved consistency in the parameter estimates when compared to sine-wave inputs.

  14. High Throughput Measurement of Ca2+ Dynamics for Drug Risk Assessment in Human Stem Cell-derived Cardiomyocytes by Kinetic Image Cytometry

    PubMed Central

    Cerignoli, Fabio; Charlot, David; Whittaker, Ross; Ingermanson, Randy; Gehalot, Piyush; Savtchenko, Alex; Gallacher, David J.; Towart, Rob; Price, Jeffrey H.; McDonough, Patrick M.; Mercola, Mark

    2013-01-01

    Current methods to measure physiological properties of cardiomyocytes and predict fatal arrhythmias that can cause sudden death, such as Torsade de Pointes, lack either the automation and throughput needed for early-stage drug discovery and/or have poor predictive value. To increase throughput and predictive power of in vitro assays, we developed kinetic imaging cytometry (KIC) for automated cell-by-cell analyses via intracellular fluorescence Ca2+ indicators. The KIC instrument simultaneously records and analyzes intracellular calcium concentration [Ca2+]i at 30-ms resolution from hundreds of individual cells/well of 96-well plates in seconds, providing kinetic details not previously possible with well averaging technologies such as plate readers. Analyses of human embryonic stem cell and induced pluripotent stem cell-derived cardiomyocytes revealed effects of known cardiotoxic and arrhythmogenic drugs on kinetic parameters of Ca2+ dynamics, suggesting that KIC will aid in the assessment of cardiotoxic risk and in the elucidation of pathogenic mechanisms of heart disease associated with drugs treatment and/or genetic background. PMID:22926323

  15. Quantitative prediction of radio frequency induced local heating derived from measured magnetic field maps in magnetic resonance imaging: A phantom validation at 7 T

    NASA Astrophysics Data System (ADS)

    Zhang, Xiaotong; Van de Moortele, Pierre-Francois; Liu, Jiaen; Schmitter, Sebastian; He, Bin

    2014-12-01

    Electrical Properties Tomography (EPT) technique utilizes measurable radio frequency (RF) coil induced magnetic fields (B1 fields) in a Magnetic Resonance Imaging (MRI) system to quantitatively reconstruct the local electrical properties (EP) of biological tissues. Information derived from the same data set, e.g., complex numbers of B1 distribution towards electric field calculation, can be used to estimate, on a subject-specific basis, local Specific Absorption Rate (SAR). SAR plays a significant role in RF pulse design for high-field MRI applications, where maximum local tissue heating remains one of the most constraining limits. The purpose of the present work is to investigate the feasibility of such B1-based local SAR estimation, expanding on previously proposed EPT approaches. To this end, B1 calibration was obtained in a gelatin phantom at 7 T with a multi-channel transmit coil, under a particular multi-channel B1-shim setting (B1-shim I). Using this unique set of B1 calibration, local SAR distribution was subsequently predicted for B1-shim I, as well as for another B1-shim setting (B1-shim II), considering a specific set of parameter for a heating MRI protocol consisting of RF pulses plaid at 1% duty cycle. Local SAR results, which could not be directly measured with MRI, were subsequently converted into temperature change which in turn were validated against temperature changes measured by MRI Thermometry based on the proton chemical shift.

  16. Biological evaluation of the radioiodinated imidazo[1,2-a]pyridine derivative DRK092 for amyloid-? imaging in mouse model of Alzheimer's disease.

    PubMed

    Chen, Chun-Jen; Bando, Kazunori; Ashino, Hiroki; Taguchi, Kazumi; Shiraishi, Hideaki; Shima, Keiji; Fujimoto, Osuke; Kitamura, Chiemi; Morimoto, Yasuaki; Kasahara, Hiroyuki; Minamizawa, Takao; Jiang, Cheng; Zhang, Ming-Rong; Suhara, Tetsuya; Higuchi, Makoto; Yamada, Kazutaka; Ji, Bin

    2014-10-01

    Non-invasive determination of amyloid-? peptide (A?) deposition has important significance for early diagnosis and medical intervention in Alzheimer's disease (AD). In this study, we investigated the availability of a radioiodinated imidazo[1,2-a]pyridine derivative, termed (125)I-DRK092, as single photon emission computed tomography (SPECT) ligand for in vivo detection of A? deposition. DRK092 showed high binding affinity for either synthetic human A? fibrils or brain homogenates from amyloid precursor protein transgenic (Tg) mouse (PS1-ki/JU-Tg2576) and AD patient with a dissociation constant (Kd) of one-digit nM, and excellent brain permeability (peak value of uptake: approximately 0.9% of injection dose/g rat brain). Ex vivo autoradiographic analysis showed that measurement with (125)I-DRK092 has higher sensibility for detecting A? accumulation than with (125)I-IMPY, a well-known amyloid SPECT ligand, in Tg mice. In vitro autoradiography with (125)I-DRK092 also confirmed higher accumulation of radioactivity in the cortical area, enriched with A? plaques, of Tg mouse and AD patient brains, as compared with the corresponding areas in non-Tg mouse and healthy control brains. All the data presented above lead us to draw the conclusion that radioiodinated DRK092 is a potential SPECT ligand for amyloid imaging in AD. PMID:25172571

  17. The use of mass spectrometry imaging to predict treatment response of patient-derived xenograft models of triple-negative breast cancer.

    PubMed

    Mascini, Nadine E; Eijkel, Gert B; ter Brugge, Petra; Jonkers, Jos; Wesseling, Jelle; Heeren, Ron M A

    2015-02-01

    In recent years, mass spectrometry imaging (MSI) has been shown to be a promising technique in oncology. The effective application of MSI, however, is hampered by the complexity of the generated data. Bioinformatic approaches that reduce the complexity of these data are needed for the effective use in a (bio)medical setting. This holds especially for the analysis of tissue microarrays (TMA), which consist of hundreds of small tissue cores. Here we present an approach that combines MSI on tissue microarrays with principal component linear discriminant analysis (PCA-LDA) to predict treatment response. The feasibility of such an approach was evaluated on a set of patient-derived xenograft models of triple-negative breast cancer (TNBC). PCA-LDA was used to classify TNBC tumor tissues based on the proteomic information obtained with matrix-assisted laser desorption ionization (MALDI) MSI from the TMA surface. Classifiers based on two different tissue microarrays from the same tumor models showed overall classification accuracies between 59 and 77%, as determined by cross-validation. Reproducibility tests revealed that the two models were similar. A clear effect of intratumor heterogeneity of the classification scores was observed. These results demonstrate that the analysis of MALDI-MSI data by PCA-LDA is a valuable approach for the classification of treatment response and tumor heterogeneity in breast cancer. PMID:25553735

  18. In Acute Stroke, Can CT Perfusion-Derived Cerebral Blood Volume Maps Substitute for Diffusion-Weighted Imaging in Identifying the Ischemic Core?

    PubMed Central

    Copen, William A.; Morais, Livia T.; Wu, Ona; Schwamm, Lee H.; Schaefer, Pamela W.; González, R. Gilberto; Yoo, Albert J.

    2015-01-01

    Background and Purpose In the treatment of patients with suspected acute ischemic stroke, increasing evidence suggests the importance of measuring the volume of the irreversibly injured “ischemic core.” The gold standard method for doing this in the clinical setting is diffusion-weighted magnetic resonance imaging (DWI), but many authors suggest that maps of regional cerebral blood volume (CBV) derived from computed tomography perfusion imaging (CTP) can substitute for DWI. We sought to determine whether DWI and CTP-derived CBV maps are equivalent in measuring core volume. Methods 58 patients with suspected stroke underwent CTP and DWI within 6 hours of symptom onset. We measured low-CBV lesion volumes using three methods: “objective absolute,” i.e. the volume of tissue with CBV below each of six published absolute thresholds (0.9–2.5 mL/100 g), “objective relative,” whose six thresholds (51%-60%) were fractions of mean contralateral CBV, and “subjective,” in which two radiologists (R1, R2) outlined lesions subjectively. We assessed the sensitivity and specificity of each method, threshold, and radiologist in detecting infarction, and the degree to which each over- or underestimated the DWI core volume. Additionally, in the subset of 32 patients for whom follow-up CT or MRI was available, we measured the proportion of CBV- or DWI-defined core lesions that exceeded the follow-up infarct volume, and the maximum amount by which this occurred. Results DWI was positive in 72% (42/58) of patients. CBV maps’ sensitivity/specificity in identifying DWI-positive patients were 100%/0% for both objective methods with all thresholds, 43%/94% for R1, and 83%/44% for R2. Mean core overestimation was 156–699 mL for objective absolute thresholds, and 127–200 mL for objective relative thresholds. For R1 and R2, respectively, mean±SD subjective overestimation were -11±26 mL and -11±23 mL, but subjective volumes differed from DWI volumes by up to 117 and 124 mL in individual patients. Inter-rater agreement regarding the presence of infarction on CBV maps was poor (kappa = 0.21). Core lesions defined by the six objective absolute CBV thresholds exceeded follow-up infarct volumes for 81%-100% of patients, by up to 430–1002 mL. Core estimates produced by objective relative thresholds exceeded follow-up volumes in 91% of patients, by up to 210-280 mL. Subjective lesions defined by R1 and R2 exceeded follow-up volumes in 18% and 26% of cases, by up to 71 and 15 mL, respectively. Only 1 of 23 DWI lesions (4%) exceeded final infarct volume, by 3 mL. Conclusion CTP-derived CBV maps cannot reliably substitute for DWI in measuring core volume, or even establish which patients have DWI lesions. PMID:26193486

  19. Naval threat countermeasure simulator and the IR_CRUISE_missiles models for the generation of infrared (IR) videos of maritime targets and background for input into advanced imaging IR seekers

    NASA Astrophysics Data System (ADS)

    Taczak, Thomas M.; Dries, John W.; Gover, Robert E.; Snapp, Mary Ann; Williams, Elmer F.; Cahill, Colin P.

    2002-07-01

    A new hardware-in-the-loop modeling technique was developed at the US Naval Research Laboratory (NRL) for the evaluation of IR countermeasures against advanced IR imaging anti-ship cruise missiles. The research efforts involved the creation of tools to generate accurate IR imagery and synthesize video to inject in to real-world threat simulators. A validation study was conducted to verify the accuracy and limitations of the techniques that were developed.

  20. Functional transformations of odor inputs in the mouse olfactory bulb

    PubMed Central

    Adam, Yoav; Livneh, Yoav; Miyamichi, Kazunari; Groysman, Maya; Luo, Liqun; Mizrahi, Adi

    2014-01-01

    Sensory inputs from the nasal epithelium to the olfactory bulb (OB) are organized as a discrete map in the glomerular layer (GL). This map is then modulated by distinct types of local neurons and transmitted to higher brain areas via mitral and tufted cells. Little is known about the functional organization of the circuits downstream of glomeruli. We used in vivo two-photon calcium imaging for large scale functional mapping of distinct neuronal populations in the mouse OB, at single cell resolution. Specifically, we imaged odor responses of mitral cells (MCs), tufted cells (TCs) and glomerular interneurons (GL-INs). Mitral cells population activity was heterogeneous and only mildly correlated with the olfactory receptor neuron (ORN) inputs, supporting the view that discrete input maps undergo significant transformations at the output level of the OB. In contrast, population activity profiles of TCs were dense, and highly correlated with the odor inputs in both space and time. Glomerular interneurons were also highly correlated with the ORN inputs, but showed higher activation thresholds suggesting that these neurons are driven by strongly activated glomeruli. Temporally, upon persistent odor exposure, TCs quickly adapted. In contrast, both MCs and GL-INs showed diverse temporal response patterns, suggesting that GL-INs could contribute to the transformations MCs undergo at slow time scales. Our data suggest that sensory odor maps are transformed by TCs and MCs in different ways forming two distinct and parallel information streams. PMID:25408637

  1. Structural response and input identification

    NASA Technical Reports Server (NTRS)

    Shepard, G. D.; Callahan, J. C.; Mcelman, J. A.

    1981-01-01

    Three major goals were delineated: (1) to develop a general method for determining the response of a structure to combined base and acoustic random excitation: (2) to develop parametric relationships to aid in the design of plates which are subjected to random force or random base excitation: (3) to develop a method to identify the individual acoustic and base input to a structure with only a limited number of measurement channels, when both types of excitation act simultaneously.

  2. National hospital input price index.

    PubMed

    Freeland, M S; Anderson, G; Schendler, C E

    1979-01-01

    The national community hospital input price index presented here isolates the effects of prices of goods and services required to produce hospital care and measures the average percent change in prices for a fixed market basket of hospital inputs. Using the methodology described in this article, weights for various expenditure categories were estimated and proxy price variables associated with each were selected. The index is calculated for the historical period 1970 through 1978 and forecast for 1979 through 1981. During the historical period, the input price index increased an average of 8.0 percent a year, compared with an average rate of increase of 6.6 percent for overall consumer prices. For the period 1979 through 1981, the average annual increase is forecast at between 8.5 and 9.0 per cent. Using the index to deflate growth in expenses, the level of real growth in expenditures per inpatient day (net service intensity growth) averaged 4.5 percent per year with considerable annual variation related to government and hospital industry policies. PMID:10309052

  3. Derivatives Page

    NSDL National Science Digital Library

    Derivatives are financial securities whose value is derived from another "underlying" financial security. Options, futures, swaps, swaptions, and structured notes are all examples of derivative securities. Derivatives can be used in hedging, protecting against financial risk, or can be used to speculate on the movement of commodity or security prices, interest rates, or the levels of financial indices. The valuation of derivatives makes use of the statistical mathematics of uncertainty. With links to related articles. See also Derivatives Concepts A-Z, glossary of derivatives-related terminology designed to make the other articles in the Financial Pipeline's Derivatives section easier to understand.

  4. Single-image phase retrieval using an edge illumination X-ray phase-contrast imaging setup.

    PubMed

    Diemoz, Paul C; Vittoria, Fabio A; Hagen, Charlotte K; Endrizzi, Marco; Coan, Paola; Brun, Emmanuel; Wagner, Ulrich H; Rau, Christoph; Robinson, Ian K; Bravin, Alberto; Olivo, Alessandro

    2015-07-01

    A method is proposed which enables the retrieval of the thickness or of the projected electron density of a sample from a single input image acquired with an edge illumination phase-contrast imaging setup. The method assumes the case of a quasi-homogeneous sample, i.e. a sample with a constant ratio between the real and imaginary parts of its complex refractive index. Compared with current methods based on combining two edge illumination images acquired in different configurations of the setup, this new approach presents advantages in terms of simplicity of acquisition procedure and shorter data collection time, which are very important especially for applications such as computed tomography and dynamical imaging. Furthermore, the fact that phase information is directly extracted, instead of its derivative, can enable a simpler image interpretation and be beneficial for subsequent processing such as segmentation. The method is first theoretically derived and its conditions of applicability defined. Quantitative accuracy in the case of homogeneous objects as well as enhanced image quality for the imaging of complex biological samples are demonstrated through experiments at two synchrotron radiation facilities. The large range of applicability, the robustness against noise and the need for only one input image suggest a high potential for investigations in various research subjects. PMID:26134813

  5. Single-image phase retrieval using an edge illumination X-ray phase-contrast imaging setup

    PubMed Central

    Diemoz, Paul C.; Vittoria, Fabio A.; Hagen, Charlotte K.; Endrizzi, Marco; Coan, Paola; Brun, Emmanuel; Wagner, Ulrich H.; Rau, Christoph; Robinson, Ian K.; Bravin, Alberto; Olivo, Alessandro

    2015-01-01

    A method is proposed which enables the retrieval of the thickness or of the projected electron density of a sample from a single input image acquired with an edge illumination phase-contrast imaging setup. The method assumes the case of a quasi-homogeneous sample, i.e. a sample with a constant ratio between the real and imaginary parts of its complex refractive index. Compared with current methods based on combining two edge illumination images acquired in different configurations of the setup, this new approach presents advantages in terms of simplicity of acquisition procedure and shorter data collection time, which are very important especially for applications such as computed tomography and dynamical imaging. Furthermore, the fact that phase information is directly extracted, instead of its derivative, can enable a simpler image interpretation and be beneficial for subsequent processing such as segmentation. The method is first theoretically derived and its conditions of applicability defined. Quantitative accuracy in the case of homogeneous objects as well as enhanced image quality for the imaging of complex biological samples are demonstrated through experiments at two synchrotron radiation facilities. The large range of applicability, the robustness against noise and the need for only one input image suggest a high potential for investigations in various research subjects. PMID:26134813

  6. MegaPipe: the MegaCam image stacking pipeline at the Canadian Astronomical Data Centre

    E-print Network

    Stephen. D. J. Gwyn

    2007-10-01

    This paper describes the MegaPipe image processing pipeline at the Canadian Astronomical Data Centre. The pipeline combines multiple images from the MegaCam mosaic camera on CFHT and combines them into a single output image. MegaPipe takes as input detrended MegaCam images and does a careful astrometric and photometric calibration on them. The calibrated images are then resampled and combined into image stacks. The astrometric calibration of the output images is accurate to within 0.15 arcseconds relative to external reference frames and 0.04 arcseconds internally. The photometric calibration is good to within 0.03 magnitudes. The stacked images and catalogues derived from these images are available through the CADC website:

  7. ~ad 2 input NAND gate hex inverters

    E-print Network

    Hehner, Eric C.R.

    74LSOO _17 ~ad 2 input NAND gate 74LSO4 hex inverters 74LSO9' ONO! 7 uad 2 input AND gate (open collector) 74LS14 -n hex Schmitt trigger Pin out and Description of TTL ChipS 74LSO2 quad 2 input NOR gate NAND gate 74LSO3 GNOIf quad 2 input NAND gate (open collector) 74LSOS' quad 2 input AND gate 74LSll -17

  8. Self-consistent input-output formulation of quantum feedback

    SciTech Connect

    Yanagisawa, M. [Department of Engineering, The Australian National University, Canberra, ACT 0200 (Australia); Hope, J. J. [Department of Quantum Science, The Australian National University, Canberra, ACT 0200 (Australia)

    2010-12-15

    A simple method of analyzing quantum feedback circuits is presented. The classical analysis of feedback circuits can be generalized to apply to quantum systems by mapping the field operators of various outputs to other inputs via the standard input-output formalism. Unfortunately, this has led to unphysical results such as the violation of the Heisenberg uncertainty principle for in-loop fields. This paper shows that this general approach can be redeemed by ensuring a self-consistently Hermitian Hamiltonian. The calculations are based on a noncommutative calculus of operator derivatives. A full description of several examples of quantum linear and nonlinear feedback for optical systems is presented.

  9. Analytical derivation of distortion constraints and their verification in a learning vector quantization-based target recognition system

    NASA Astrophysics Data System (ADS)

    Iftekharuddin, Khan M.; Razzaque, Mohammad A.

    2005-06-01

    We obtain a novel analytical derivation for distortion-related constraints in a neural network- (NN)-based automatic target recognition (ATR) system. We obtain two types of constraints for a realistic ATR system implementation involving 4-f correlator architecture. The first constraint determines the relative size between the input objects and input correlation filters. The second constraint dictates the limits on amount of rotation, translation, and scale of input objects for system implementation. We exploit these constraints in recognition of targets varying in rotation, translation, scale, occlusion, and the combination of all of these distortions using a learning vector quantization (LVQ) NN. We present the simulation verification of the constraints using both the gray-scale images and Defense Advanced Research Projects Agency's (DARPA's) Moving and Stationary Target Recognition (MSTAR) synthetic aperture radar (SAR) images with different depression and pose angles.

  10. Feature maps driven no-reference image quality prediction of authentically distorted images

    NASA Astrophysics Data System (ADS)

    Ghadiyaram, Deepti; Bovik, Alan C.

    2015-03-01

    Current blind image quality prediction models rely on benchmark databases comprised of singly and synthetically distorted images, thereby learning image features that are only adequate to predict human perceived visual quality on such inauthentic distortions. However, real world images often contain complex mixtures of multiple distortions. Rather than a) discounting the effect of these mixtures of distortions on an image's perceptual quality and considering only the dominant distortion or b) using features that are only proven to be efficient for singly distorted images, we deeply study the natural scene statistics of authentically distorted images, in different color spaces and transform domains. We propose a feature-maps-driven statistical approach which avoids any latent assumptions about the type of distortion(s) contained in an image, and focuses instead on modeling the remarkable consistencies in the scene statistics of real world images in the absence of distortions. We design a deep belief network that takes model-based statistical image features derived from a very large database of authentically distorted images as input and discovers good feature representations by generalizing over different distortion types, mixtures, and severities, which are later used to learn a regressor for quality prediction. We demonstrate the remarkable competence of our features for improving automatic perceptual quality prediction on a benchmark database and on the newly designed LIVE Authentic Image Quality Challenge Database and show that our approach of combining robust statistical features and the deep belief network dramatically outperforms the state-of-the-art.

  11. Rapid synthesis and in vitro and in vivo evaluation of folic acid derivatives labeled with fluorine-18 for PET imaging of folate receptor-positive tumors.

    PubMed

    Al Jammaz, I; Al-Otaibi, B; Amer, S; Okarvi, S M

    2011-10-01

    In an attempt to visualize folate receptors that overexpress on many cancers, [(18)F]-fluorobenzene and pyridinecarbohydrazide-folate/methotrexate conjugates ([(18)F]-1, [(18)F]-2-folates and [(18)F]-8, [(18)F]-9-MTXs) were synthesized by the nucleophilic displacement reactions using ethyl-trimethylammonium-benzoate and pyridinecarboxylate precursors. The intermediates ethyl [(18)F]-fluorinated benzene and pyridine esters were reacted with hydrazine to produce the [(18)F]-fluorobenzene and pyridinecarbohydrazides, followed by coupling with N-hydroxysuccinimide-folate/MTX. Radiochemical yields were greater than 80% (decay corrected), with total synthesis time of less than 45 min. Radiochemical purities were always greater than 97% without high-performance liquid chromatography purification. These synthetic approaches hold considerable promise as rapid and simple method for the radiofluorination of folate derivatives with high radiochemical yield in short synthesis time. In vitro tests on KB cell line showed that significant amount of the radioconjugates were associated with cell fractions, and in vivo characterization in normal Balb/c mice revealed rapid blood clearance of these radioconjugates with excretion predominantly by the urinary and partially by the hepatobiliary systems. Biodistribution studies in nude mice bearing human KB cell line xenografts demonstrated significant tumor uptake and favorable biodistribution profile for [(18)F]-2-folate over the other conjugates. The uptake in the tumors was blocked by excess coinjection of folic acid, suggesting a receptor-mediated process. Micro-positron emission tomography images of nude mice bearing human KB cell line xenografts confirmed these observations. These results demonstrate that [(18)F]-2-folate may be useful as molecular probe for detecting and staging of folate receptor-positive cancers, such as ovarian cancer and their metastasis as well as monitoring tumor response to treatment. PMID:21982573

  12. Dust deflation by dust devils on Mars derived from optical depth measurements using the shadow method in HiRISE images

    NASA Astrophysics Data System (ADS)

    Reiss, D.; Hoekzema, N. M.; Stenzel, O. J.

    2014-04-01

    We measured the optical depth of three separate dust devils and their surroundings with the so called "shadow method" in HiRISE images. The calculated optical depths of the dust devils range from 0.29±0.18 to 1.20±0.38. Conservative calculations of the minimum and maximum dust loads are in the range of 4-122 mg m-3. Assuming reliable upper and lower boundary values of vertical speeds within the dust devils between 0.1 and 10 ms-1 based on terrestrial and Martian studies we derived dust fluxes in the range of 6.3-1221 mg m-2 s-1 (PSP_004285_1375), from 0.38-162 mg m-2 s-1 (ESP_013545_1110), and from 3.2-581 mg m-2 s-1 (ESP_016306_2410) for the three dust devils. Our dust load and dust flux calculations for the three dust devils are in good agreement to previous studies. Two of the analyzed dust devils left continuous dark tracks on the surface. For these dust devils we could calculate how much dust was removed by using the minimum and maximum dust fluxes in combination with measured horizontal speeds of these dust devils. Our results indicate that a dust removal of an equivalent layer of less than 2 ?m (or less than one monolayer) is sufficient for the formation of dust devil tracks on Mars. This value might be used in future studies to estimate the contribution of dust devils to the global dust entrainment into the atmosphere on Mars.

  13. Please cite this article in press as: Guo H, et al. FDGPET parametric imaging by total variation minimization. Comput Med Imaging Graph (2009), doi:10.1016/j.compmedimag.2009.01.005

    E-print Network

    Renaut, Rosemary

    2009-01-01

    as the output, tissue TAC or TTAC, and the TAC from the blood pool (image-derived or arterial blood-sampled) as the input, plasma TAC or PTAC. Most existing quantification methods perform well for regions of interest perform the quantification at each voxel location separately; they do not consider the kinetic

  14. Power allocation for block-fading channels with arbitrary input constellations

    Microsoft Academic Search

    Lars K. Rasmussen; Albert Guillen I Fabregas; Khoa D. Nguyen

    2009-01-01

    We consider power allocation strategies for arbi- trary input channels with peak, average and peak-to-average power ratio (PAPR) constraints. We are focusing on systems with a fixed and finite input constellation, as encountered in most prac- tical systems. Generalizing previous results, we derive the optimal power allocation scheme that minimizes the outage probability of block-fading channels with arbitrary input constellations,

  15. Programmable remapper for image processing

    NASA Technical Reports Server (NTRS)

    Juday, Richard D. (inventor); Sampsell, Jeffrey B. (inventor)

    1991-01-01

    A video-rate coordinate remapper includes a memory for storing a plurality of transformations on look-up tables for remapping input images from one coordinate system to another. Such transformations are operator selectable. The remapper includes a collective processor by which certain input pixels of an input image are transformed to a portion of the output image in a many-to-one relationship. The remapper includes an interpolative processor by which the remaining input pixels of the input image are transformed to another portion of the output image in a one-to-many relationship. The invention includes certain specific transforms for creating output images useful for certain defects of visually impaired people. The invention also includes means for shifting input pixels and means for scrolling the output matrix.

  16. Reduction of the input current harmonic content in matrix converters under input\\/output unbalance

    Microsoft Academic Search

    Domenico Casadei; Giovanni Serra; Angelo Tani

    1998-01-01

    This paper deals with the performance evaluation of space-vector-modulated matrix power converters under input and output unbalanced conditions. Two control strategies of the input current displacement angle are presented and compared in order to emphasize their influence on the input current harmonic content. The first is based on keeping the input current vector in phase with the input voltage vector.

  17. Input Variable Selection for Hydrologic Modeling Using Anns

    NASA Astrophysics Data System (ADS)

    Ganti, R.; Jain, A.

    2011-12-01

    The use of artificial neural network (ANN) models in water resources applications has grown considerably over the last couple of decades. In learning problems, where a connectionist network is trained with a finite sized training set, better generalization performance is often obtained when unneeded weights in the network are eliminated. One source of unneeded weights comes from the inclusion of input variables that provide little information about the output variables. Hence, in the ANN modeling methodology, one of the approaches that has received little attention, is the selection of appropriate model inputs. In the past, different methods have been used for identifying and eliminating these input variables. Normally, linear methods of Auto Correlation Function (ACF) and Partial Auto Correlation Function (PACF) have been adopted. For nonlinear physical systems e.g. hydrological systems, model inputs selected based on the linear correlation analysis among input and output variables cannot assure to capture the non-linearity in the system. In the present study, two of the non-linear methods have been explored for the Input Variable Selection (IVS). The linear method employing ACF and PACF is also used for comparison purposes. The first non-linear method utilizes a measure of the Mutual Information Criterion (MIC) to characterize the dependence between a potential model input and the output, which is a step wise input selection procedure. The second non-linear method is improvement over the first method which eliminates redundant inputs based on a partial measure of mutual information criterion (PMIC), which is also a step wise procedure. Further, the number of input variables to be considered for the development of ANN model was determined using the Principal Component Analysis (PCA), which previously used to be done by trial and error approach. The daily river flow data derived from Godavari River Basin @ Polavaram, Andhra Pradesh, India, and the daily average rainfall data of three rain gauge stations spatially distributed in Godavari River Basin have been employed to evaluate all the IVS methods for ANN hydrologic model development. Single hidden layer architecture trained using Levenberg-Marquardt algorithm (LMA) has been employed. A wide range of error statistics was used to evaluate the performance of all the models developed with different input selection methods in this study. It has been found that PCA helps to fix the number of input variables to be considered for the model development. The results obtained show that the ANN hydrologic model developed using the inputs based on the first non-linear method performed better than the model developed using the inputs based on the linear method. Further, the ANN hydrologic model developed using the inputs based on the second non-linear method performed the best among all the models developed on various IVS methods investigated in this study. It is recommended that PCA should first be used to determine the number of inputs to be selected and then the second non-linear method should be used to select the specific inputs for the development of ANN hydrologic model.

  18. Human-in-the-Loop: Terminal constraint receding horizon control with human inputs

    Microsoft Academic Search

    Rahul Chipalkatty; Magnus Egerstedt

    2010-01-01

    This paper presents a control theoretic formulation and optimal control solution for integrating human control inputs subject to linear state constraints. The formulation utilizes a receding horizon optimal controller to update the control effort given the most recent state and human control input information. The novel solution to the corresponding finite horizon optimal control problem with terminal constraint is derived

  19. A zero-placement technique for designing shaped inputs to suppress multiple-mode vibration

    Microsoft Academic Search

    Timothy D. Tuttle; Warren P. Seering

    1994-01-01

    The performance of many flexible systems can be improved by employing command shaping techniques to reduce machine vibration. The input shaping technique, in particular, has proven to be highly effective for a wide class of systems. Due to the mathematical complexity of higher-order problems, multiple-mode input shapers can be tricky to derive and difficult to understand. This paper proposes a

  20. Finite time observation of nonlinear time-delay systems with unknown inputs

    E-print Network

    Paris-Sud XI, Université de

    Finite time observation of nonlinear time-delay systems with unknown inputs G. Zheng J.-P. Barbot in this paper for nonlinear time- delay systems. By extending the Lie derivative for time-delay systems condition in order to deal with causal and non-causal observations of state and unknown inputs of time-delay

  1. Performance Analysis of Wireless Single Input Multiple Output Systems (SIMO) in

    E-print Network

    Kouroupetroglou, Georgios

    Performance Analysis of Wireless Single Input Multiple Output Systems (SIMO) in Correlated Weibull the statistical characteristics of the trivariate and quadrivariate Weibull fading distribution with arbitrary expressions for important joint statistics are derived using the Weibull power transformation

  2. 77 FR 54902 - Proposed Information Collection; Comment Request; Input From Hawaii's Boat-based Anglers

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-09-06

    ...Collection; Comment Request; Input From Hawaii's Boat-based Anglers AGENCY: National...National Data Standards. The State of Hawaii is developing a comprehensive data collection...fishing catch and effort derived from Hawaii's private boaters--a required...

  3. Capacity of Power Constrained Memoryless AWGN Channels with Fixed Input Constellations

    E-print Network

    Kavcic, Aleksandar

    Capacity of Power Constrained Memoryless AWGN Channels with Fixed Input Constellations #3; Nedeljko constellation constraint and 2) a maximum power constraint. We also consider nearly optimal codes derived from

  4. Gradient echo plural contrast imaging--signal model and derived contrasts: T2*, T1, phase, SWI, T1f, FST2*and T2*-SWI.

    PubMed

    Luo, Jie; Jagadeesan, Bharathi D; Cross, Anne H; Yablonskiy, Dmitriy A

    2012-04-01

    Gradient Echo Plural Contrast Imaging (GEPCI) is a post processing technique that, based on a widely available multiple gradient echo sequence, allows simultaneous generation of naturally co-registered images with various contrasts: T1 weighted, R2*=1/T2* maps and frequency (f) maps. Herein, we present results demonstrating the capability of GEPCI technique to generate image sets with additional contrast characteristics obtained by combing the information from these three basic contrast maps. Specifically, we report its ability to generate GEPCI-susceptibility weighted images (GEPCI-SWI) with improved SWI contrast that is free of T1 weighting and RF inhomogeneities; GEPCI-SWI-like images with the contrast similar to original SWI; T1f images that offer superior GM/WM matter contrast obtained by combining the GEPCI T1 and frequency map data; Fluid Suppressed T2* (FST2*) images that utilize GEPCI T1 data to suppress CSF signal in T2* maps and provide contrast similar to FLAIR T2 weighted images; and T2*-SWI images that combine SWI contrast with quantitative T2* map and offer advantages of visualizing venous structure with hyperintense T2* lesions (e.g. MS lesions). To analyze GEPCI images we use an improved algorithm for combining data from multi-channel RF coils and a method for unwrapping phase/frequency maps that takes advantage of the information on phase evolution as a function of gradient echo time in GEPCI echo train. PMID:22305993

  5. Multiple input electrode gap controller

    DOEpatents

    Hysinger, C.L.; Beaman, J.J.; Melgaard, D.K.; Williamson, R.L.

    1999-07-27

    A method and apparatus for controlling vacuum arc remelting (VAR) furnaces by estimation of electrode gap based on a plurality of secondary estimates derived from furnace outputs. The estimation is preferably performed by Kalman filter. Adaptive gain techniques may be employed, as well as detection of process anomalies such as glows. 17 figs.

  6. Multiple input electrode gap controller

    DOEpatents

    Hysinger, Christopher L. (Austin, TX); Beaman, Joseph J. (Austin, TX); Melgaard, David K. (Albuquerque, NE); Williamson, Rodney L. (Albuquerque, NE)

    1999-01-01

    A method and apparatus for controlling vacuum arc remelting (VAR) furnaces by estimation of electrode gap based on a plurality of secondary estimates derived from furnace outputs. The estimation is preferably performed by Kalman filter. Adaptive gain techniques may be employed, as well as detection of process anomalies such as glows.

  7. Increasing adder efficiency by exploiting input statistics

    E-print Network

    Clough, Andrew Lawrence

    2008-01-01

    Current techniques for characterizing the power consumption of adders rely on assuming that the inputs are completely random. However, the inputs generated by realistic applications are not random, and in fact include a ...

  8. Detection of Floating Inputs in Logic Circuits

    NASA Technical Reports Server (NTRS)

    Cash, B.; Thornton, M. G.

    1984-01-01

    Simple modification of oscilloscope probe allows easy detection of floating inputs or tristate outputs in digital-IC's. Oscilloscope probe easily modified with 1/4 W resistor and switch for detecting floating inputs in CMOS logic circuits.

  9. Generation of RTL verification input stimulus 

    E-print Network

    Selvarathinam, Anand Manivannan

    2001-01-01

    . The effectiveness of the input stimulus can effect coverage of design errors. The input test vectors (input stimulus), hence plays a significant role in verification by simulation. Therefore some guidelines are required for selecting the input vectors from all.... He has worked with tools such as cadence, synopsys and xilinx. His projects include design of various processors such as MIPS and LANai. In VSNL (India), he was involved in a case study of state of the art communication techniques. He can...

  10. Tracking of In-111-labeled human umbilical tissue-derived cells (hUTC) in a rat model of cerebral ischemia using SPECT imaging

    PubMed Central

    2012-01-01

    Background In order to increase understanding of how infused cells work, it becomes important to track their initial movement, localization, and engraftment efficiency following transplantation. However, the available in vivo cell tracking techniques are suboptimal. The study objective was to determine the biodistribution of intravenously administered Indium-111 (In-111) oxine labeled human umbilical tissue-derived cells (hUTC) in a rat model of transient middle cerebral occlusion (tMCAo) using single photon emission computed tomography (SPECT). Methods Rats received 3 million In-111 labeled hUTC (i.v.) 48?hrs after tMCAo. Following the administration of either hUTC or equivalent dose of In-111-oxine (18.5?MBq), animals underwent SPECT imaging on days 0, 1, and 3. Radioactivity in various organs as well as in the stroke area and contralateral hemisphere was determined, decay corrected and normalized to the total (whole body including head) radioactivity on day 0. Immunohistochemical analysis was also performed to confirm the beneficial effects of hUTC on vascular and synaptic density, and apoptosis. Results Most of the radioactivity (43.36±23.07% on day 0) trafficked to the lungs immediately following IV administration of In-111 labeled hUTC (day 0) and decreased drastically to 8.81±7.75 and 4.01±4.52% on days 1 and 3 post-injection, respectively. In contrast, radioactivity measured in the lung of animals that received In-111-oxine alone remained relatively unchanged from day 0 to day 1 (18.38±5.45% at day 0 to 12.59±5.94%) and decreased to 8.34±4.25% on day 3. Significantly higher radioactivity was observed in stroke areas of animals that received In-111 labeled hUTC indicating the presence of cells at the site of injury representing approximately 1% of total administered dose. In addition, there was significant increase in vascular and synaptophysin immunoreactivity in stroke areas of rats that received In-111 labeled hUTC. Conclusions The present studies showed the tracking of In-111 labeled hUTC to the sites of stroke in a rat model of tMCAo using SPECT. Animals treated with In-111 labeled hUTC showed histological improvements, with higher vascular and synaptic densities observed in the ischemic boundary zone (IBZ). PMID:23217090

  11. Young lava flows on the eastern flank of Ascraeus Mons: Rheological properties derived from High Resolution Stereo Camera (HRSC) images and Mars Orbiter Laser Altimeter (MOLA) data

    NASA Astrophysics Data System (ADS)

    Hiesinger, H.; Head, J. W.; Neukum, G.

    2007-05-01

    We report on estimates of the rheological properties of late-stage lava flows on the eastern flank of Ascraeus Mons, Mars. From previous studies it is known that the dimensions of flows reflect rheological properties such as yield strength, effusion rates, and viscosity. Our estimates are based on new high-resolution images obtained by the High Resolution Stereo Camera (HRSC) on board the European Space Agency's Mars Express spacecraft in combination with Mars Orbiter Laser Altimeter (MOLA) data. Compared to earlier studies, the high spatial resolution of the HRSC and MOLA data allowed us to map 25 late-stage lava flows and to measure their dimensions, as well as their morphological characteristics, in greater detail. Our estimates of the yield strengths for these flows range from ~2.0 × 102 Pa to ~1.3 × 105 Pa, with an average of ~2.1 × 104 Pa. These values are in good agreement with estimates for terrestrial basaltic lava flows and are comparable to previous estimates derived for a small number of lava flows on Ascraeus Mons. Our investigation indicates that the effusion rates for the studied Ascraeus Mons flows are on average ~185 m3 s-1, ranging from ~23 m3 s-1 to ~404 m3 s-1. These results are higher than earlier findings that indicate effusion rates of 18-60 m3 s-1, with an average of 35 m3 s-1. However, our effusion rates are similar to terrestrial effusion rates of Kilauea and Mauna Loa and other Martian volcanoes. On the basis of our estimates of the effusion rates and the measured dimensions of the flows, we calculated that the time necessary to emplace the flows is on average ~26 days. Viscosities were estimated on the basis of yield strengths and effusion rates, yielding average values of ~4.1 × 106 Pa-s and ranging from ~1.8 × 104 Pa-s to ~4.2 × 107 Pa-s. On the basis of newly available data sets (e.g., HRSC, MOLA) we are now able not only to identify possible differences in eruptive behavior between Ascraeus Mons and Elysium Mons but also to study such differences over time.

  12. A storage model with self-similar input

    Microsoft Academic Search

    Ilkka Norros

    1994-01-01

    A storage model with self-similar input process is studied. A relation coupling together the storage requirement, the achievable utilization and the output rate is derived. A lower bound for the complementary distribution function of the storage level is given. Keywords: Self-similar, fractional Brownian motion, Local Area Network traffic 1 Introduction In a series of papers (e.g. Leland [8], Leland and

  13. Multiple-input-multiple-output measurements and modeling in Manhattan

    Microsoft Academic Search

    Dmitry Chizhik; Jonathan Ling; Peter W. Wolniansky; Reinaldo A. Valenzuela; Nelson Costa; Kris Huber

    2003-01-01

    Narrowband multiple-input-multiple-output (MIMO) measurements using 16 transmitters and 16 receivers at 2.11 GHz were carried out in Manhattan. High capacities were found for full, as well as smaller array configurations, all within 80% of the fully scattering channel capacity. Correlation model parameters are derived from data. Spatial MIMO channel capacity statistics are found to be well represented by the separate

  14. Random Oracles and Auxiliary Input Dominique Unruh

    E-print Network

    Random Oracles and Auxiliary Input Dominique Unruh Saarland University, Saarbr¨ucken, Germany, u r h c . n - b dn u @ s u i s . e Abstract. We introduce a variant of the random oracle model where oracle-dependent auxiliary input is allowed. In this setting, the adversary gets an auxiliary input

  15. Textual Enhancement of Input: Issues and Possibilities

    ERIC Educational Resources Information Center

    Han, ZhaoHong; Park, Eun Sung; Combs, Charles

    2008-01-01

    The input enhancement hypothesis proposed by Sharwood Smith (1991, 1993) has stimulated considerable research over the last 15 years. This article reviews the research on textual enhancement of input (TE), an area where the majority of input enhancement studies have aggregated. Methodological idiosyncrasies are the norm of this body of research.…

  16. Efficient input—output model representations

    Microsoft Academic Search

    Herschel Rabitz; Ömer F. Ali?; Jeffrey Shorter; Kyurhee Shim

    1999-01-01

    A family of multivariate representations is presented to capture the input—output relationships of physical systems with many input variables. The high-dimensional model representations (HDMR) are based on the ansatz that for most physical systems, only relatively low order correlations of the input variables will have an impact on the output. Application of the HDMR tools can dramatically reduce the computational

  17. Countering Poisonous Inputs with Memetic Neuroevolution

    E-print Network

    Togelius, Julian

    Countering Poisonous Inputs with Memetic Neuroevolution Julian Togelius1 , Tom Schaul1 , J-dimensional and/or ill-chosen state description. Evidently, some controller inputs are "poisonous also ex- plore which types of inputs are poisonous for two different reinforcement learning problems. 1

  18. Honeybee navigation: odometry with monocular input.

    PubMed

    Srinivasan; Zhang; Lehrer

    1998-11-01

    Recent studies have revealed that navigating honeybees, Apis mellifera, estimate the distance to a food source by integrating over time the image motion that they experience en route. Here we examine the ability of honeybees to gauge distance travelled when visual input is available primarily to one eye. Bees were trained to fly into a tunnel, lined with textured patterns, to collect a reward at a feeder placed at a certain distance. Their ability to estimate distance flown was then assessed by testing them in a fresh tunnel without the feeder. The results show that (1) bees can estimate distance flown under monocular conditions, performing nearly as accurately as when information is available to both eyes; (2) bees can learn to fly two different distances, where each distance is measured in terms of the image motion experienced by a different eye; and (3) bees that have acquired information on the distance to a food source using one eye can measure out the same distance when they are required to use the other (naive) eye. The need to measure distance using signals from a single eye becomes important when a bee flies to a food source along the face of a cliff or the edge of a forest. Furthermore, under such conditions, it is important to be able to deal with odometric signals that are transposed interocularly when the bee returns home from the food source. This is because, although distances are learnt primarily on the way to a food source, foraging bees monitor distance flown on the homebound as well as the outbound routes. Copyright 1998 The Association for the Study of Animal Behaviour. PMID:9819342

  19. Rendering Layered Depth Images

    Microsoft Academic Search

    Steven J. Gortler; Li-wei He; Michael F. Cohen

    1997-01-01

    In this paper we present an efficient image based rendering system that renders multipleframes per second on a PC. Our method performs warping from an intermediate representationcalled a layered depth image (LDI). An LDI is a view of the scene from a single inputcamera view, but with multiple pixels along each line of sight. When n input images arepreprocessed to

  20. Masticator space abscess derived from odontogenic infection: imaging manifestation and pathways of extension depicted by CT and MR in 30 patients

    Microsoft Academic Search

    B. Schuknecht; G. Stergiou; K. Graetz

    2008-01-01

    Propagation of odontogenic masticator space abscesses is insufficiently understood. The purpose was to analyse pathways of\\u000a spread in 30 patients with odontogenic masticator space abscess. The imaging findings in 30 patients (CT in 30, MR in 16 patients)\\u000a were retrospectively analysed. CT and MR imaging depicted a masticator space abscess within: medial pterygoid muscle in 13\\u000a patients (43.3%), lateral masseter

  1. Shallow sea-floor reflectance and water depth derived by unmixing multispectral imagery

    SciTech Connect

    Bierwirth, P.N.; Lee, T.J.; Burne, R.V. (Marine Spill Response Corp., Washington, DC (United States) Michigan Environmental Research Inst., Ann Arbor (United States))

    1993-03-01

    A major problem for mapping shallow water zones by the analysis of remotely sensed data is that contrast effects due to water depth obscure and distort the special nature of the substrate. This paper outlines a new method which unmixes the exponential influence of depth in each pixel by employing a mathematical constraint. This leaves a multispectral residual which represents relative substrate reflectance. Input to the process are the raw multispectral data and water attenuation coefficients derived by the co-analysis of known bathymetry and remotely sensed data. Outputs are substrate-reflectance images corresponding to the input bands and a greyscale depth image. The method has been applied in the analysis of Landsat TM data at Hamelin Pool in Shark Bay, Western Australia. Algorithm derived substrate reflectance images for Landsat TM bands 1, 2, and 3 combined in color represent the optimum enhancement for mapping or classifying substrate types. As a result, this color image successfully delineated features, which were obscured in the raw data, such as the distributions of sea-grasses, microbial mats, and sandy area. 19 refs.

  2. Turn customer input into innovation.

    PubMed

    Ulwick, Anthony W

    2002-01-01

    It's difficult to find a company these days that doesn't strive to be customer-driven. Too bad, then, that most companies go about the process of listening to customers all wrong--so wrong, in fact, that they undermine innovation and, ultimately, the bottom line. What usually happens is this: Companies ask their customers what they want. Customers offer solutions in the form of products or services. Companies then deliver these tangibles, and customers just don't buy. The reason is simple--customers aren't expert or informed enough to come up with solutions. That's what your R&D team is for. Rather, customers should be asked only for outcomes--what they want a new product or service to do for them. The form the solutions take should be up to you, and you alone. Using Cordis Corporation as an example, this article describes, in fine detail, a series of effective steps for capturing, analyzing, and utilizing customer input. First come indepth interviews, in which a moderator works with customers to deconstruct a process or activity in order to unearth "desired outcomes." Addressing participants' comments one at a time, the moderator rephrases them to be both unambiguous and measurable. Once the interviews are complete, researchers then compile a comprehensive list of outcomes that participants rank in order of importance and degree to which they are satisfied by existing products. Finally, using a simple mathematical formula called the "opportunity calculation," researchers can learn the relative attractiveness of key opportunity areas. These data can be used to uncover opportunities for product development, to properly segment markets, and to conduct competitive analysis. PMID:12964470

  3. Initial evaluation of virtual un-enhanced imaging derived from fast kVp-switching dual energy contrast enhanced CT for the abdomen

    NASA Astrophysics Data System (ADS)

    Joshi, M.; Mendonca, P.; Okerlund, D.; Lamb, P.; Kulkarni, N.; Pinho, D.; Sahani, D.; Bhotika, R.

    2011-03-01

    The feasibility and utility of creating virtual un-enhanced images from contrast enhanced data acquired using a fast switching dual energy CT acquisition, is explored. Utilizing projection based material decomposition data, monochromatic images are generated and a Multi-material decomposition technique is applied. Quantitative and qualitative evaluation is performed to assess the equivalence of Virtual Un-Enhanced (VUE) and True Un-enhanced (TUE) for multiple tissue types and different organs in the abdomen. Ten patient cases were analyzed where a TUE and a subsequent Contrast Enhanced (CE) acquisition were obtained using fast kVp-switching dual energy CT utilizing Gemstone Spectral Imaging. Quantitative measurements were made by placing multiple Regions of Interest on the different tissues and organs in both the TUE and the VUE images. The absolute Hounsfield Unit (HU) differences in the mean values between TUE & VUE were calculated as well as the differences of the standard deviations. Qualitative analysis was done by two radiologists for overall image quality, presence of residual contrast, appearance of pathology, appearance and contrast of normal tissues and organs in comparison to the TUE. There is a very strong correlation between the TUE and VUE images.

  4. Quantitative assessment of multiple sclerosis lesion load using CAD and expert input

    NASA Astrophysics Data System (ADS)

    Gertych, Arkadiusz; Wong, Alexis; Sangnil, Alan; Liu, Brent J.

    2008-03-01

    Multiple sclerosis (MS) is a frequently encountered neurological disease with a progressive but variable course affecting the central nervous system. Outline-based lesion quantification in the assessment of lesion load (LL) performed on magnetic resonance (MR) images is clinically useful and provides information about the development and change reflecting overall disease burden. Methods of LL assessment that rely on human input are tedious, have higher intra- and inter-observer variability and are more time-consuming than computerized automatic (CAD) techniques. At present it seems that methods based on human lesion identification preceded by non-interactive outlining by CAD are the best LL quantification strategies. We have developed a CAD that automatically quantifies MS lesions, displays 3-D lesion map and appends radiological findings to original images according to current DICOM standard. CAD is also capable to display and track changes and make comparison between patient's separate MRI studies to determine disease progression. The findings are exported to a separate imaging tool for review and final approval by expert. Capturing and standardized archiving of manual contours is also implemented. Similarity coefficients calculated from quantities of LL in collected exams show a good correlation of CAD-derived results vs. those incorporated as expert's reading. Combining the CAD approach with an expert interaction may impact to the diagnostic work-up of MS patients because of improved reproducibility in LL assessment and reduced time for single MR or comparative exams reading. Inclusion of CAD-generated outlines as DICOM-compliant overlays into the image data can serve as a better reference in MS progression tracking.

  5. Understand compression algorithm. Given an input string, create the compressed code.

    E-print Network

    Allan, Vicki H.

    · Units of storage understood 1-2 Units of storage understood Terms ­ compression ­ lossless of storage (images, sound, text). Understanding compression makes you a better user of a computer. · Image2/27/2009 1 Objectives · Understand compression algorithm. · Given an input string, create

  6. Measures of diversity should include both matrix and vector inputs Root Gorelick

    E-print Network

    Gorelick, Root

    Commentary Measures of diversity should include both matrix and vector inputs Root Gorelick generalizations encompassed in the Hill­Tsallis indices often can and should map a matrix or higher-order array conflict with the calculus-derived economics connotation of `marginal' as a derivative. A potential problem

  7. Input estimation from measured structural response

    SciTech Connect

    Harvey, Dustin [Los Alamos National Laboratory; Cross, Elizabeth [Los Alamos National Laboratory; Silva, Ramon A [Los Alamos National Laboratory; Farrar, Charles R [Los Alamos National Laboratory; Bement, Matt [Los Alamos National Laboratory

    2009-01-01

    This report will focus on the estimation of unmeasured dynamic inputs to a structure given a numerical model of the structure and measured response acquired at discrete locations. While the estimation of inputs has not received as much attention historically as state estimation, there are many applications where an improved understanding of the immeasurable input to a structure is vital (e.g. validating temporally varying and spatially-varying load models for large structures such as buildings and ships). In this paper, the introduction contains a brief summary of previous input estimation studies. Next, an adjoint-based optimization method is used to estimate dynamic inputs to two experimental structures. The technique is evaluated in simulation and with experimental data both on a cantilever beam and on a three-story frame structure. The performance and limitations of the adjoint-based input estimation technique are discussed.

  8. The ubiquitous DOTA and its derivatives: the impact of 1,4,7,10-tetraazacyclododecane-1,4,7,10-tetraacetic acid on biomedical imaging.

    PubMed

    Stasiuk, Graeme J; Long, Nicholas J

    2013-04-01

    Over the last twenty-five years 1,4,7,10-tetraazacyclododecane-1,4,7,10-tetraacetic acid (DOTA) has made a significant impact on the field of diagnostic imaging. DOTA is not the only metal chelate in use in medical diagnostics, but it is the only one to significantly impact on all of the major imaging modalities Magnetic Resonance (MR), Positron Emission Tomography (PET), Single Photon Emission Computed Tomography (SPECT), and Fluorescence imaging. This crossover of modalities has been possible due to the versatility of DOTA firstly, to complex a variety of metal ions and secondly, the ease with which it can be modified for different disease states. This has driven research over the last two decades into the chemistry of DOTA and the modification of the substituent pendant arms of this macrocycle to create functional, targeted and dual-modal imaging agents. The primary use of DOTA has been with the lanthanide series of metals, gadolinium for MRI, europium and terbium for fluorescence and neodymium for near infra-red imaging. There are now many research groups dedicated to the use of lanthanides with DOTA although other chelates such as DTPA and NOTA are being increasingly employed. The ease with which DOTA can be conjugated to peptides has given rise to targeted imaging agents seen in the PET, SPECT and radiotherapy fields. These modalities use a variety of radiometals that complex with DOTA, e.g.(64)Cu and (68)Ga which are used in clinical PET scans, (111)In, and (90)Y for SPECT and radiotherapy. In this article, we will demonstrate the remarkable versatility of DOTA, how it has crossed the imaging modality boundaries and how it has been successfully transferred into the clinic. PMID:23392443

  9. Image enhancement by non-linear extrapolation in frequency space

    NASA Technical Reports Server (NTRS)

    Anderson, Charles H. (Inventor); Greenspan, Hayit K. (Inventor)

    1998-01-01

    An input image is enhanced to include spatial frequency components having frequencies higher than those in an input image. To this end, an edge map is generated from the input image using a high band pass filtering technique. An enhancing map is subsequently generated from the edge map, with the enhanced map having spatial frequencies exceeding an initial maximum spatial frequency of the input image. The enhanced map is generated by applying a non-linear operator to the edge map in a manner which preserves the phase transitions of the edges of the input image. The enhanced map is added to the input image to achieve a resulting image having spatial frequencies greater than those in the input image. Simplicity of computations and ease of implementation allow for image sharpening after enlargement and for real-time applications such as videophones, advanced definition television, zooming, and restoration of old motion pictures.

  10. Input characterization of a shock test strructure.

    SciTech Connect

    Hylok, J. E. (Jeffrey E.); Groethe, M. A.; Maupin, R. D. (Ryan D.)

    2004-01-01

    Often in experimental work, measuring input forces and pressures is a difficult and sometimes impossible task. For one particular shock test article, its input sensitivity required a detailed measurement of the pressure input. This paper discusses the use of a surrogate mass mock test article to measure spatial and temporal variations of the shock input within and between experiments. Also discussed will be the challenges and solutions in making some of the high speed transient measurements. The current input characterization work appears as part of the second phase in an extensive model validation project. During the first phase, the system under analysis displayed sensitivities to the shock input's qualitative and quantitative (magnitude) characteristics. However, multiple shortcomings existed in the characterization of the input. First, the experimental measurements of the input were made on a significantly simplified structure only, and the spatial fidelity of the measurements was minimal. Second, the sensors used for the pressure measurement contained known errors that could not be fully quantified. Finally, the measurements examined only one input pressure path (from contact with the energetic material). Airblast levels from the energetic materials were unknown. The result was a large discrepancy between the energy content in the analysis and experiments.

  11. Assessment of interannual variations in the surface mass balance of 18 Svalbard glaciers from the Moderate Resolution Imaging Spectroradiometer\\/Terra albedo product

    Microsoft Academic Search

    Wouter Greuell; Jack Kohler; Friedrich Obleitner; Piotr Glowacki; Kjetil Melvold; Erik Bernsen; Johannes Oerlemans

    2007-01-01

    We estimate annual anomalies of the surface mass balance of glaciers on Svalbard for the period 2000-2005 (six years), by calculating the so-called ``satellite-derived mass balance'' (B sat ) from time series of satellite-derived surface albedos. The method needs no other input variables. Surface albedos are extracted from the Moderate Resolution Imaging Spectroradiometer (MODIS)\\/Terra albedo product. We validate the MODIS

  12. Assessment of interannual variations in the surface mass balance of 18 Svalbard glaciers from the Moderate Resolution Imaging Spectroradiometer\\/Terra albedo product

    Microsoft Academic Search

    Wouter Greuell; Jack Kohler; Friedrich Obleitner; Piotr Glowacki; Kjetil Melvold; Erik Bernsen; Johannes Oerlemans

    2007-01-01

    We estimate annual anomalies of the surface mass balance of glaciers on Svalbard for the period 2000–2005 (six years), by calculating the so-called “satellite-derived mass balance” (Bsat) from time series of satellite-derived surface albedos. The method needs no other input variables. Surface albedos are extracted from the Moderate Resolution Imaging Spectroradiometer (MODIS)\\/Terra albedo product. We validate the MODIS albedos by

  13. Microchannel cross load array with dense parallel input

    DOEpatents

    Swierkowski, Stefan P.

    2004-04-06

    An architecture or layout for microchannel arrays using T or Cross (+) loading for electrophoresis or other injection and separation chemistry that are performed in microfluidic configurations. This architecture enables a very dense layout of arrays of functionally identical shaped channels and it also solves the problem of simultaneously enabling efficient parallel shapes and biasing of the input wells, waste wells, and bias wells at the input end of the separation columns. One T load architecture uses circular holes with common rows, but not columns, which allows the flow paths for each channel to be identical in shape, using multiple mirror image pieces. Another T load architecture enables the access hole array to be formed on a biaxial, collinear grid suitable for EDM micromachining (square holes), with common rows and columns.

  14. Robust model predictive control design with input constraints.

    PubMed

    Veselý, Vojtech; Rosinová, Danica; Foltin, Martin

    2010-01-01

    The paper addresses the problem of designing a robust output/state model predictive control for linear polytopic systems with input constraints. The new predictive and control horizon model is derived as a linear polytopic system. Lyapunov function approach guarantees the quadratic stability and guaranteed cost for closed-loop system. The invariant set and an algorithm approach similar to Soft Variable-Structure Control (SVSC), ensures input constraints for the model predictive plant control system. In the proposed control scheme, the required on-line computation load is significantly less than in MPC literature, which opens the possibility to use these control design schemes not only for plants with slow dynamics, but also for faster ones. PMID:19853851

  15. Pseudo-telepathy: input cardinality and Bell-type inequalities

    E-print Network

    N. Gisin; A. A. Methot; V. Scarani

    2006-10-20

    Pseudo-telepathy is the most recent form of rejection of locality. Many of its properties have already been discovered: for instance, the minimal entanglement, as well as the minimal cardinality of the output sets, have been characterized. This paper contains two main results. First, we prove that no bipartite pseudo-telepathy game exists, in which one of the partners receives only two questions; as a corollary, we show that the minimal "input cardinality", that is, the minimal number of questions required in a bipartite pseudo-telepathy game, is 3x3. Second, we study the Bell-type inequality derived from the pseudo-telepathy game known as the Magic Square game: we demonstrate that it is a tight inequality for 3 inputs and 4 outputs on each side and discuss its weak resistance to noise.

  16. NeuroMorph: a toolset for the morphometric analysis and visualization of 3D models derived from electron microscopy image stacks.

    PubMed

    Jorstad, Anne; Nigro, Biagio; Cali, Corrado; Wawrzyniak, Marta; Fua, Pascal; Knott, Graham

    2015-01-01

    Serialelectron microscopy imaging is crucial for exploring the structure of cells and tissues. The development of block face scanning electron microscopy methods and their ability to capture large image stacks, some with near isotropic voxels, is proving particularly useful for the exploration of brain tissue. This has led to the creation of numerous algorithms and software for segmenting out different features from the image stacks. However, there are few tools available to view these results and make detailed morphometric analyses on all, or part, of these 3D models. We have addressed this issue by constructing a collection of software tools, called NeuroMorph, with which users can view the segmentation results, in conjunction with the original image stack, manipulate these objects in 3D, and make measurements of any region. This approach to collecting morphometric data provides a faster means of analysing the geometry of structures, such as dendritic spines and axonal boutons. This bridges the gap that currently exists between rapid reconstruction techniques, offered by computer vision research, and the need to collect measurements of shape and form from segmented structures that is currently done using manual segmentation methods. PMID:25240318

  17. Utilization of NASA MODerate Resolution Imaging Spectroradiometer (MODIS) Derived Aerosol Optical Depth (AOD) for Trends Analysis Over the United States-Canada Border Region

    Microsoft Academic Search

    J. L. Dewinter; B. E. Tisdale; A. L. Ross; K. E. Keith; E. Hodges Petty; A. M. Yates; M. D. Tisdale; D. Smith; J. L. Lister; D. C. Rainney; M. Sarper; D. Jackson; D. O. Neil; C. Kittaka; J. A. Engel-Cox; R. M. Hoff; J. Szykman

    2007-01-01

    A systematic and comprehensive method of air pollutant trends analysis is critical in benchmarking change in air quality conditions and informing policy makers (EPA, 2007; Environment Canada, 2006; NARSTO, 2004). AOD derived from the MODIS instrument aboard the NASA Terra and Aqua satellites is correlated with the ground- based AErosol RObotic NETwork (AERONET, AEROCAN in Canada) AOD and compared to

  18. Early characterization of the active fire detection products derived from the next generation NPOESS\\/VIIRS and GOES-R\\/ABI instruments

    Microsoft Academic Search

    Wilfrid Schroeder; Ivan Csiszar; Louis Giglio; Evan Ellicott; Christopher C. Schmidt; Jay P. Hoffman; Scott Lindstrom

    2010-01-01

    In this study, we discuss the early characterization of the active fire products derived from NPOESS\\/VIIRS and GOES-R ABI proxy data generated using ASTER and MODIS L1B input data, respectively. Improvements in spatial resolution of both VIIRS and ABI instruments result in higher probability of detection compared to their predecessors (MODIS and GOES Imager, respectively). The onboard pixel aggregation scheme

  19. Converging cerebellofugal inputs to the thalamus

    Microsoft Academic Search

    L. Rispal-Padel; D. Troiani; C. Harnois

    1987-01-01

    A large number of projections from cerebellar nuclei converge onto individual neurones in the thalamic relay to the motor cortex. Among the thalamic cells receiving cerebellar inputs, 75 out of 153 (50%) were found to be influenced by monosynaptic inputs from at least two cerebellar nuclei and 2 (1.5%) from three nuclei (the interpositus, dentate and fastigial nuclei). The pathways

  20. An Automated Mechanism for Secure Input Handling

    Microsoft Academic Search

    Jin-Cherng Lin; Jan-Min Chen

    2009-01-01

    Numbers of the programs are poorly written, lacking even the most basic security procedures for handling input data from users. The input validation vulnerability can be detected by many tools but few tools can fix the flaws automatically. The security gateway can used to protect vulnerable Web sites immediately but it may induce false recognition through impersonal rule. By means

  1. Human-computer interaction: input devices

    Microsoft Academic Search

    Robert J. K. Jacob

    1996-01-01

    All aspects of human-computer interaction, from the high-level concerns of organizational context and system requirements to the conceptual, semantic, syntactic, and lexical levels of user interface design, are ultimately funneled through physical input and output actions and devices. The fundamental task in computer input is to move information from the brain of the user to the computer. Progress in this

  2. The Input Hypothesis: An Inside Look.

    ERIC Educational Resources Information Center

    Higgs, Theodore V.

    1985-01-01

    Summarizes and discusses Krashen's "input hypothesis" as presented in his "Principles and Practice in Second Language Acquisition." Suggests that the input hypothesis fails to account convincingly for arrested second language acquisition in an acquisition-rich environment and that it is not directly applicable to U.S. high school and university…

  3. CASSAVA AGRONOMY IN INDIA - LOW INPUT MANAGEMENT

    Microsoft Academic Search

    T. V. R. Nayar; G. Suja; K. Susan John; V. Ravi

    Agronomic research on cassava in India during the past three decades was instrumental in the development of management practices that led to substantial increases in yield, mainly in Tamil Nadu and Kerala. Research efforts have recently focused on the development of low-input technologies with special emphasis on the identification of genotypes adapted to low-input conditions, the utilization of locally available

  4. Handprinting Input device for computer systems

    Microsoft Academic Search

    J. G. Simek; C. J. Tunis

    1967-01-01

    As of the present moment, the slowest process in computer technology is data preparation and the input operation. Among the proposed solutions to this problem are direct-reading handprinting input devices that boast of at least 95 percent accuracy. Character recognition is accomplished by means of linear decision functions, which are designed using an adaptive procedure. This technique allows flexibility in

  5. Testing Calculation Engines Input Space Partitioning &

    E-print Network

    Offutt, Jeff

    approach (proposed) · Test case design - Input Space Partitioning · Test case design - Modeling with ToolTesting Calculation Engines using Input Space Partitioning & Automation Thesis for the MS engine. ­ e.g. Financial models, Valuation models, Pricing models, Risk assessment models · Errors

  6. Modality of Input and Vocabulary Acquisition

    ERIC Educational Resources Information Center

    Sydorenko, Tetyana

    2010-01-01

    This study examines the effect of input modality (video, audio, and captions, i.e., on-screen text in the same language as audio) on (a) the learning of written and aural word forms, (b) overall vocabulary gains, (c) attention to input, and (d) vocabulary learning strategies of beginning L2 learners. Twenty-six second-semester learners of Russian…

  7. Replenishment of magma chambers by light inputs

    Microsoft Academic Search

    Herbert E. Huppert; R. Stephen; J. Sparks; John A. Whitehead; Mark A. Halloworth

    1986-01-01

    Magma chambers, particularly those of basaltic composition, are often replenished by an influx of magma whose density is less than that of the resident magma. This paper describes the fundamental fluid mechanics involved in the replenishment by light inputs. If rho denotes the uniform density of the resident magma and rho-Deltarho that the input, the situation is described by the

  8. Imports of intermediate inputs and plant survival

    Microsoft Academic Search

    Ricardo A. López

    2006-01-01

    Previous studies have analyzed the effect of exporting on plant survival. No work has been done examining the role of importing intermediate inputs on survival. Using plant-level data from Chile we find that importing intermediate inputs increases the probability of survival.

  9. Statistical identification of effective input variables. [SCREEN

    SciTech Connect

    Vaurio, J.K.

    1982-09-01

    A statistical sensitivity analysis procedure has been developed for ranking the input data of large computer codes in the order of sensitivity-importance. The method is economical for large codes with many input variables, since it uses a relatively small number of computer runs. No prior judgemental elimination of input variables is needed. The sceening method is based on stagewise correlation and extensive regression analysis of output values calculated with selected input value combinations. The regression process deals with multivariate nonlinear functions, and statistical tests are also available for identifying input variables that contribute to threshold effects, i.e., discontinuities in the output variables. A computer code SCREEN has been developed for implementing the screening techniques. The efficiency has been demonstrated by several examples and applied to a fast reactor safety analysis code (Venus-II). However, the methods and the coding are general and not limited to such applications.

  10. Kernel principal component analysis for stochastic input model generation

    SciTech Connect

    Ma Xiang [Materials Process Design and Control Laboratory, Sibley School of Mechanical and Aerospace Engineering, 101 Frank H.T. Rhodes Hall, Cornell University, Ithaca, NY 14853-3801 (United States); Zabaras, Nicholas, E-mail: zabaras@cornell.edu [Materials Process Design and Control Laboratory, Sibley School of Mechanical and Aerospace Engineering, 101 Frank H.T. Rhodes Hall, Cornell University, Ithaca, NY 14853-3801 (United States)

    2011-08-10

    Highlights: {yields} KPCA is used to construct a reduced order stochastic model of permeability. {yields} A new approach is proposed to solve the pre-image problem in KPCA. {yields} Polynomial chaos is used to provide a parametric stochastic input model. {yields} Flow in porous media with channelized permeability is considered. - Abstract: Stochastic analysis of random heterogeneous media provides useful information only if realistic input models of the material property variations are used. These input models are often constructed from a set of experimental samples of the underlying random field. To this end, the Karhunen-Loeve (K-L) expansion, also known as principal component analysis (PCA), is the most popular model reduction method due to its uniform mean-square convergence. However, it only projects the samples onto an optimal linear subspace, which results in an unreasonable representation of the original data if they are non-linearly related to each other. In other words, it only preserves the first-order (mean) and second-order statistics (covariance) of a random field, which is insufficient for reproducing complex structures. This paper applies kernel principal component analysis (KPCA) to construct a reduced-order stochastic input model for the material property variation in heterogeneous media. KPCA can be considered as a nonlinear version of PCA. Through use of kernel functions, KPCA further enables the preservation of higher-order statistics of the random field, instead of just two-point statistics as in the standard Karhunen-Loeve (K-L) expansion. Thus, this method can model non-Gaussian, non-stationary random fields. In this work, we also propose a new approach to solve the pre-image problem involved in KPCA. In addition, polynomial chaos (PC) expansion is used to represent the random coefficients in KPCA which provides a parametric stochastic input model. Thus, realizations, which are statistically consistent with the experimental data, can be generated in an efficient way. We showcase the methodology by constructing a low-dimensional stochastic input model to represent channelized permeability in porous media.

  11. Defect detection in aluminum foil by input-estimate-based chi-square detector

    NASA Astrophysics Data System (ADS)

    Zhai, Ming; Jing, Zhongliang; Fu, Shan; Luo, Xinbin

    2009-11-01

    Quality inspection of aluminum foil products plays an important role for aluminum foil manufactures. We present a method that uses input estimate (IE)-based chi-square detectors for defect detection in aluminum foil. It is assumed that the intensity of the aluminum foil image is Gaussian distributed, and the distribution of the defect intensity is different from the normal. Under these assumptions, Kalman filters with a constant velocity (CV) model are used to filter the image. We assume there is an unknown input in the CV model and the unknown input is estimated in the filtering process. The defects are determined by the chi-square test of the estimate of the unknown input. Experiments show that our technique is effective for most defects in aluminum foil.

  12. Measuring Input Thresholds on an Existing Board

    NASA Technical Reports Server (NTRS)

    Kuperman, Igor; Gutrich, Daniel G.; Berkun, Andrew C.

    2011-01-01

    A critical PECL (positive emitter-coupled logic) interface to Xilinx interface needed to be changed on an existing flight board. The new Xilinx input interface used a CMOS (complementary metal-oxide semiconductor) type of input, and the driver could meet its thresholds typically, but not in worst-case, according to the data sheet. The previous interface had been based on comparison with an external reference, but the CMOS input is based on comparison with an internal divider from the power supply. A way to measure what the exact input threshold was for this device for 64 inputs on a flight board was needed. The measurement technique allowed an accurate measurement of the voltage required to switch a Xilinx input from high to low for each of the 64 lines, while only probing two of them. Directly driving an external voltage was considered too risky, and tests done on any other unit could not be used to qualify the flight board. The two lines directly probed gave an absolute voltage threshold calibration, while data collected on the remaining 62 lines without probing gave relative measurements that could be used to identify any outliers. The PECL interface was forced to a long-period square wave by driving a saturated square wave into the ADC (analog to digital converter). The active pull-down circuit was turned off, causing each line to rise rapidly and fall slowly according to the input s weak pull-down circuitry. The fall time shows up as a change in the pulse width of the signal ready by the Xilinx. This change in pulse width is a function of capacitance, pulldown current, and input threshold. Capacitance was known from the different trace lengths, plus a gate input capacitance, which is the same for all inputs. The pull-down current is the same for all inputs including the two that are probed directly. The data was combined, and the Excel solver tool was used to find input thresholds for the 62 lines. This was repeated over different supply voltages and temperatures to show that the interface had voltage margin under all worst case conditions. Gate input thresholds are normally measured at the manufacturer when the device is on a chip tester. A key function of this machine was duplicated on an existing flight board with no modifications to the nets to be tested, with the exception of changes in the FPGA program.

  13. Suppression of motion-induced residual longitudinal vibration of an elastic rod by input shaping

    Microsoft Academic Search

    T.-S. Yang; K.-S. Chen; C.-C. Lee; I. Hu

    2007-01-01

    Various input-shaping schemes such as the “zero-vibration” (ZV), “zero-vibration-and-derivative” (ZVD), “negative ZV” (NZV),\\u000a and “negative ZVD” (NZVD) schemes have previously been proposed to suppress motion-induced residual vibration of lightly damped\\u000a structures. In such schemes, the input command of the dynamical system in question is properly administered (i.e., shaped), so that the dominant induced vibration modes are annihilated through destructive interference.

  14. Quantization noise in single-loop sigma-delta modulation with sinusoidal inputs

    Microsoft Academic Search

    ROBERT M. GRAY; W. Chou; P. W. Wong

    1989-01-01

    An exact nonlinear difference equation is derived and solved for a simple sigma-delta modulator consisting of a discrete-time integrator and a binary quantizer inside a single feedback loop and an arbitrary input signal. It is shown that the system can be represented as an affine operation (discrete-time integration of a biased input) followed by a memoryless nonlinearity. An extension of

  15. Structure, temporal evolution, and heat flux estimates from the Lucky Strike deep-sea hydrothermal field derived from seafloor image mosaics

    NASA Astrophysics Data System (ADS)

    Barreyre, Thibaut; EscartíN, Javier; Garcia, Rafael; Cannat, Mathilde; Mittelstaedt, Eric; Prados, Ricard

    2012-04-01

    Here we demonstrate with a study of the Lucky Strike hydrothermal field that image mosaicing over large seafloor areas is feasible with new image processing techniques, and that repeated surveys allow temporal studies of active processes. Lucky Strike mosaics, generated from >56,000 images acquired in 1996, 2006, 2008 and 2009, reveal the distribution and types of diffuse outflow throughout the field, and their association with high-temperature vents. In detail, the zones of outflow are largely controlled by faults, and we suggest that the spatial clustering of active zones likely reflects the geometry of the underlying plumbing system. Imagery also provides constraints on temporal variability at two time-scales. First, based upon changes in individual outflow features identified in mosaics acquired in different years, we document a general decline of diffuse outflow throughout the vent field over time-scales up to 13 years. Second, the image mosaics reveal broad patches of seafloor that we interpret as fossil outflow zones, owing to their association with extinct chimneys and hydrothermal deposits. These areas encompass the entire region of present-day hydrothermal activity, suggesting that the plumbing system has persisted over long periods of time, loosely constrained to hundreds to thousands of years. The coupling of mosaic interpretation and available field measurements allow us to independently estimate the heat flux of the Lucky Strike system at ˜200 to 1000 MW, with 75% to >90% of this flux taken up by diffuse hydrothermal outflow. Based on these heat flux estimates, we propose that the temporal decline of the system at short and long time scales may be explained by the progressive cooling of the AMC, without replenishment. The results at Lucky Strike demonstrate that repeated image surveys can be routinely performed to characterize and study the temporal variability of a broad range of vent sites hosting active processes (e.g., cold seeps, hydrothermal fields, gas outflows, etc.), allowing a better understanding of fluid flow dynamics from the sub-seafloor, and a quantification of fluxes.

  16. Adaptive stereoscopic image conversion of 2D image

    NASA Astrophysics Data System (ADS)

    Lee, Jong-Ho; Kim, Jung-Jin; Kim, Eun-Soo

    2001-11-01

    In recent years, there have been many researches being done throughout the world on the 3D image conversion of 2D image. However, 3D image conversion of 2D image has many problems on obtaining the optimal stereopsis. Stereopsis is dominated to relative position of several objects and depth information within image. Accordingly, in this paper, as a new adaptive scheme for stereoscopic image conversion of 2D image is suggested. Two input images acquired by Stereo Camera have different disparity information to each other. Disparity map, based on disparity information, presents mutually different occulusion region in the left/right image. These depend on the left view & right view and front & rear view of the virtual image plane. If arbitrary threshold values are applied to disparity map, we can get segmented objects from the input image. Using the principle of horizontal parallax, segmented objects are shifted with optimal screen disparity. In this case, we can improve stereopsis by differential shifting.

  17. Neural networks for fast image compression 

    E-print Network

    Li, Mu

    1998-01-01

    of digital image data in the areas of remote sensing, medical imaging, earth observation, digital libraries and documents, high definition television (HDTV), multimedia, world wide web(WWYV) system, and vedioconferencing, digital image compression... called neurons or nodes. A basic neuron model consists of the following features: inputs, weights, a bias, a summation operation, an activation function, and an output. Each node can have several input branches but only one output branch. Each input...

  18. Wireless, relative-motion computer input device

    DOEpatents

    Holzrichter, John F.; Rosenbury, Erwin T.

    2004-05-18

    The present invention provides a system for controlling a computer display in a workspace using an input unit/output unit. A train of EM waves are sent out to flood the workspace. EM waves are reflected from the input unit/output unit. A relative distance moved information signal is created using the EM waves that are reflected from the input unit/output unit. Algorithms are used to convert the relative distance moved information signal to a display signal. The computer display is controlled in response to the display signal.

  19. Micromachined dual input axis rate gyroscope

    NASA Astrophysics Data System (ADS)

    Juneau, Thor Nelson

    The need for inexpensive yet reliable angular rate sensors in fields ranging from automotive to consumer electronics has motivated prolific micromachined rate gyroscope research. The vast majority of research has focused on single input axis rate gyroscopes based upon either translational resonance, such as tuning forks, or structural mode resonance, such as vibrating rings. However, this work presents a novel, contrasting approach based on angular resonance of a rotating rigid rotor suspended by torsional springs. The inherent symmetry of the circular design allows angular rate measurement about two axes simultaneously, hence the name micromachined dual-axis rate gyroscope. The underlying theory of operation, mechanical structure design optimization, electrical interface circuitry, and signal processing are described in detail. Several operational versions were fabricated using two different fully integrated surface micromachining processes as proof of concept. The heart of the dual-axis rate gyroscope is a ˜2 mum thick polysilicon disk or rotor suspended above the substrate by a four beam suspension. When this rotor in driven into angular oscillation about the axis perpendicular to the substrate, a rotation rate about the two axes parallel to the substrate invokes an out of plane rotor tilting motion due to Coriolis acceleration. This tilting motion is capacitively measured and on board integrated signal processing provides two output voltages proportional to angular rate input about the two axes parallel to the substrate. The design process begins with the derivation of gyroscopic dynamics. The equations suggest that tuning sense mode frequencies to the drive oscillation frequency can vastly increase mechanical sensitivity. Hence the supporting four beam suspension is designed such that electrostatic tuning can match modes despite process variations. The electrostatic tuning range is limited only by rotor collapse to the substrate when tuning-voltage induced electrostatic forces over power the beam suspension. Multivariable design optimization is used to maximize performance given process constraints. All electronics needed to sustain rotor oscillation, control oscillation amplitude, sense rotor tilting due to Coriolis acceleration, and process sense signals to produce voltage outputs are explained. A voltage controlled oscillator slaved to the structure oscillation through a phase-lock-loop is used as the master clock to produce all signals needed for signal processing and amplitude control. Thus, the micromachine serves as both a rotation sensor and a frequency reference. Final versions fabricated by Sandia National Laboratory were fully integrated and therefore required only passive components and electrical sources off-chip. Without electrostatic tuning, dual-axis rate gyroscopes achieved 0.1sp°/sec/sqrt{Hz} noise level. This provided automotive grade performance of approximately 1sp°/sec noise floor over a 100 Hz bandwidth. Electrical tuning decreased noise to below 0.02sp°/sec/sqrt{Hz}. However, open-loop operation with nearly matched sense and drive modes can result in higher cross-axis sensitivity, scale factor drift, and phase errors. Closed-loop feedback methods which alleviate these problems as well as reduce offset drift due to quadrature error are presented as future directions.

  20. A record of hydrocarbon input to San Francisco Bay as traced by biomarker profiles in surface sediment and sediment cores

    Microsoft Academic Search

    Frances D. Hostettler; Wilfred E. Pereira; Keith A. Kvenvolden; Alexander van Geen; Samuel N. Luoma; Christopher C. Fuller; Roberto Anima

    1999-01-01

    San Francisco Bay is one of the world's largest urbanized estuarine systems. Its water and sediment receive organic input from a wide variety of sources; much of this organic material is anthropogenically derived. To document the spatial and historical record of the organic contaminant input, surficial sediment from 17 sites throughout San Francisco Bay and sediment cores from two locations—Richardson

  1. Deriving the Intrahepatic Arteriovenous Shunt Rate from CT Images and Biochemical Data Instead of from Arterial Perfusion Scintigraphy in Hepatic Arterial Infusion Chemotherapy

    SciTech Connect

    Ozaki, Toshiro, E-mail: ganronbun@amail.plala.or.jp; Seki, Hiroshi; Shiina, Makoto [Niigata Cancer Center Hospital, Department of Radiology (Japan)

    2009-09-15

    The purpose of the present study was to elucidate a method for predicting the intrahepatic arteriovenous shunt rate from computed tomography (CT) images and biochemical data, instead of from arterial perfusion scintigraphy, because adverse exacerbated systemic effects may be induced in cases where a high shunt rate exists. CT and arterial perfusion scintigraphy were performed in patients with liver metastases from gastric or colorectal cancer. Biochemical data and tumor marker levels of 33 enrolled patients were measured. The results were statistically verified by multiple regression analysis. The total metastatic hepatic tumor volume (V{sub metastasized}), residual hepatic parenchyma volume (V{sub residual}; calculated from CT images), and biochemical data were treated as independent variables; the intrahepatic arteriovenous (IHAV) shunt rate (calculated from scintigraphy) was treated as a dependent variable. The IHAV shunt rate was 15.1 {+-} 11.9%. Based on the correlation matrixes, the best correlation coefficient of 0.84 was established between the IHAV shunt rate and V{sub metastasized} (p < 0.01). In the multiple regression analysis with the IHAV shunt rate as the dependent variable, the coefficient of determination (R{sup 2}) was 0.75, which was significant at the 0.1% level with two significant independent variables (V{sub metastasized} and V{sub residual}). The standardized regression coefficients ({beta}) of V{sub metastasized} and V{sub residual} were significant at the 0.1 and 5% levels, respectively. Based on this result, we can obtain a predicted value of IHAV shunt rate (p < 0.001) using CT images. When a high shunt rate was predicted, beneficial and consistent clinical monitoring can be initiated in, for example, hepatic arterial infusion chemotherapy.

  2. Using digital image processing to characterize the Campbell-Stokes sunshine recorder and to derive high-temporal resolution direct solar irradiance

    NASA Astrophysics Data System (ADS)

    Sanchez-Romero, A.; González, J. A.; Calbó, J.; Sanchez-Lorenzo, A.

    2014-09-01

    The Campbell-Stokes sunshine recorder (CSSR) has been one of the most commonly used instruments for measuring sunshine duration (SD) through the burn length of a given CSSR card. Many authors have used SD to obtain information about cloudiness and solar radiation (by using Ångström-Prescott type formulas). Contrarily, the burn width has not been used systematically. In principle, the burn width increases for increasing direct beam irradiance. The aim of this research is to show the relationship between burn width and direct solar irradiance (DSI), and to prove whether this relationship depends on the type of CSSR and burning card. A semi-automatic method based on image processing of digital scanned images of burnt cards is presented. With this method, the temporal evolution of the burn width with 1 min resolution can be obtained. From this, SD is easily calculated and compared with the traditional (i.e. visual) determination. The method tends to slightly overestimate SD but the thresholds that are used in the image processing could be adjusted to obtain an unbiased estimation. Regarding the burn width, results show that there is a high correlation between two different models of CSSRs, as well as a strong relationship between burn widths and DSI at a high-temporal resolution. Thus, for example, hourly DSI may be estimated from the burn width with higher accuracy than based on burn length (for one of the CSSR, relative root mean squared error 24 and 30% respectively; mean bias error -0.6 and -30.0 W m-2 respectively). The method offers a practical way to exploit long-term sets of CSSR cards to create long time series of DSI. Since DSI is affected by atmospheric aerosol content, CSSR records may also become a proxy measurement for turbidity and atmospheric aerosol loading.

  3. Using digital image processing to characterize the Campbell-Stokes sunshine recorder and to derive high-temporal resolution direct solar irradiance

    NASA Astrophysics Data System (ADS)

    Sanchez-Romero, A.; González, J. A.; Calbó, J.; Sanchez-Lorenzo, A.

    2015-01-01

    The Campbell-Stokes sunshine recorder (CSSR) has been one of the most commonly used instruments for measuring sunshine duration (SD) through the burn length of a given CSSR card. Many authors have used SD to obtain information about cloudiness and solar radiation (by using Ångström-Prescott type formulas), but the burn width has not been used systematically. In principle, the burn width increases for increasing direct beam irradiance. The aim of this research is to show the relationship between burn width and direct solar irradiance (DSI) and to prove whether this relationship depends on the type of CSSR and burning card. A method of analysis based on image processing of digital scanned images of burned cards is used. With this method, the temporal evolution of the burn width with 1 min resolution can be obtained. From this, SD is easily calculated and compared with the traditional (i.e., visual) determination. The method tends to slightly overestimate SD, but the thresholds that are used in the image processing could be adjusted to obtain an improved estimation. Regarding the burn width, experimental results show that there is a high correlation between two different models of CSSRs, as well as a strong relationship between burn widths and DSI at a high-temporal resolution. Thus, for example, hourly DSI may be estimated from the burn width with higher accuracy than based on burn length (for one of the CSSR, relative root mean squared error is 24 and 30%, respectively; mean bias error is -0.6 and -30.0 W m-2, respectively). The method offers a practical way to exploit long-term sets of CSSR cards to create long time series of DSI. Since DSI is affected by atmospheric aerosol content, CSSR records may also become a proxy measurement for turbidity and atmospheric aerosol loading.

  4. Automatic pH Control and Soluble and Insoluble Substrate Input for Continuous Culture of Rumen Microorganisms

    PubMed Central

    Slyter, Leonard L.

    1975-01-01

    An artifical rumen continuous culture with pH control, automated input of water-soluble and water-insoluble substrates, controlled mixing of contents, and a collection system for gas is described. Images PMID:16350029

  5. Complex derivatives

    NASA Astrophysics Data System (ADS)

    Battiston, Stefano; Caldarelli, Guido; Georg, Co-Pierre; May, Robert; Stiglitz, Joseph

    2013-03-01

    The intrinsic complexity of the financial derivatives market has emerged as both an incentive to engage in it, and a key source of its inherent instability. Regulators now faced with the challenge of taming this beast may find inspiration in the budding science of complex systems.

  6. Fast Hue and Range Preserving Histogram: Specification: Theory and New Algorithms for Color Image Enhancement.

    PubMed

    Nikolova, Mila; Steidl, Gabriele

    2014-07-16

    Color image enhancement is a complex and challenging task in digital imaging with abundant applications. Preserving the hue of the input image is crucial in a wide range of situations. We propose simple image enhancement algorithms which conserve the hue and preserve the range (gamut) of the R, G, B channels in an optimal way. In our setup, the intensity input image is transformed into a target intensity image whose histogram matches a specified, well-behaved histogram. We derive a new color assignment methodology where the resulting enhanced image fits the target intensity image. We analyse the obtained algorithms in terms of chromaticity improvement and compare them with the unique and quite popular histogram based hue and range preserving algorithm of Naik and Murthy. Numerical tests confirm our theoretical results and show that our algorithms perform much better than the Naik-Murthy algorithm. In spite of their simplicity, they compete with well-established alternative methods for images where hue-preservation is desired. PMID:25051550

  7. 7 CFR 3430.15 - Stakeholder input.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ...input. Section 103(c)(2) of the Agricultural Research, Extension, and Education Reform Act of 1998...program RFA from persons who conduct agricultural research, education, and extension for use in formulating future RFAs...

  8. Two Input Polyhedra User Correspondence Specification

    E-print Network

    Whitton, Mary C.

    Two Input Polyhedra User Correspondence Specification through Decomposition into Mapping Merging Reconstruction Merged Polyhedron Isomorphic Polyhedra Editing of Morphing Trajectories Interpolation of Morphing-specified morphing between arbitrary polyhedra Department of Computer Science University of North Carolina at Chapel

  9. Generation of RTL verification input stimulus

    E-print Network

    Selvarathinam, Anand Manivannan

    2001-01-01

    intervention. Simulation is widely used for verifying RTL designs despite its limitation. For a given coverage metric, the verification input vectors are generated to attain a higher level of coverage. Many verification coverage measures were proposed...

  10. Auditory Input: Effects on Performance and Behavior.

    ERIC Educational Resources Information Center

    Hooker, Spencer A.

    1985-01-01

    An informal study suggested that although auditory input affects and often interferes with learning, especially in learning disabled children, the students learn to cope with the interference. The importance of considering all learning modalities was stressed. (CL)

  11. Syntheses of 2-Amino and 2-Halothiazole Derivatives as High-Affinity Metabotropic Glutamate Receptor Subtype 5 Ligands and Potential Radioligands for In Vivo Imaging

    PubMed Central

    Siméon, Fabrice G; Wendahl, Matthew T.; Pike, Victor W.

    2011-01-01

    The structure of the potent selective mGlu5 ligand, SP203 (1, 3-fluoro-5-[[2-(fluoromethyl)thiazol-4-yl]ethynyl]benzonitrile), was modified by replacing the 2-fluoromethyl substituent with an amino or halo substituent and by variation of substituents in the distal aromatic ring to provide a series of new high-affinity mGlu5 ligands. In this series, among the most potent ligands obtained, the 2-chloro-thiazoles 7a and 7b and the 2-fluorothiazole 10b showed sub-nanomolar mGlu5 affinity. 10b also displayed >10,000-fold selectivity over all other metabotropic receptor subtypes plus a wide range of other receptors and binding sites. The 2-fluorothiazoles 10a and 10b were labeled using [18F]fluoride ion (t1/2 = 109.7 min) in moderately high radiochemical yield to provide potential radioligands that may resist troublesome radiodefluorination during the imaging of brain mGlu5 with position emission tomography. The iodo compound 9b has nanomolar affinity for mGlu5 and may also serve as a lead to a potential 123I-labeled ligand for imaging brain mGlu5 with single photon emission computed tomography. PMID:21207959

  12. Fluorine-Substituted Cyclofenil Derivatives as Estrogen Receptor Ligands: Synthesis and Structure-Affinity Relationship Study of Potential PET Agents for Imaging Estrogen Receptors in Breast Cancer

    PubMed Central

    Seo, Jai Woong; Comninos, John S.; Chi, Dae Yoon; Kim, Dong Wook; Carlson, Kathryn E.; Katzenellenbogen, John A.

    2008-01-01

    In a search for estrogen receptor (ER) ligands to be radiolabeled with fluorine-18 for imaging of ER-positive breast tumors with positron emission tomography (PET), we investigated cyclofenil analogs substituted at the C3 or C4 position of the cyclohexyl group. McMurry coupling of 4,4?-dihydroxybenzophenone with various ketones produced key cyclofenil intermediates, from which C3 and C4 substituents containing alkyl and various oxygen or fluorine-substituted alkyl groups were elaborated. Binding assays to both ER? and ER? revealed that the C3 site is more tolerant of steric bulk and polar groups than the C4 site, consistent with a computational model of the ER? ligand binding pocket. Fluorine substitution is tolerated very well at some sites, giving some compounds having affinities comparable to or higher than that of estradiol. These fluoro and fluoroalkyl cyclofenils merit further consideration as fluorine-18 labeled ER ligands for PET imaging of ERs in breast tumors. PMID:16610793

  13. Evaluation of entropy and JM-distance criterions as features selection methods using spectral and spatial features derived from LANDSAT images

    NASA Technical Reports Server (NTRS)

    Parada, N. D. J. (principal investigator); Dutra, L. V.; Mascarenhas, N. D. A.; Mitsuo, Fernando Augusta, II

    1984-01-01

    A study area near Ribeirao Preto in Sao Paulo state was selected, with predominance in sugar cane. Eight features were extracted from the 4 original bands of LANDSAT image, using low-pass and high-pass filtering to obtain spatial features. There were 5 training sites in order to acquire the necessary parameters. Two groups of four channels were selected from 12 channels using JM-distance and entropy criterions. The number of selected channels was defined by physical restrictions of the image analyzer and computacional costs. The evaluation was performed by extracting the confusion matrix for training and tests areas, with a maximum likelihood classifier, and by defining performance indexes based on those matrixes for each group of channels. Results show that in spatial features and supervised classification, the entropy criterion is better in the sense that allows a more accurate and generalized definition of class signature. On the other hand, JM-distance criterion strongly reduces the misclassification within training areas.

  14. Testing Input\\/Output Partial Order Automata

    Microsoft Academic Search

    Stefan Haar; Claude Jard; Guy-vincent Jourdan

    2007-01-01

    We propose an extension of the Finite State Machine frame- work in distributed systems, using input\\/output partial order automata (IOPOA). In this model, transitions can be executed non-atomically, reacting to asynchronous inputs on several ports, and producing asyn- chronous output on those ports. We develop the formal framework for distributed testing in this architecture and compare with the synchronous I\\/O

  15. Lattice QCD input for axion cosmology

    E-print Network

    Evan Berkowitz; Michael I. Buchoff; Enrico Rinaldi

    2015-05-27

    One intriguing BSM particle is the QCD axion, which could simultaneously provide a solution to the Strong CP problem and account for some, if not all, of the dark matter density in the universe. This particle is a pNGB of the conjectured Peccei-Quinn (PQ) symmetry of the Standard Model. Its mass and interactions are suppressed by a heavy symmetry breaking scale, $f_a$, whose value is roughly greater than $10^{9}$ GeV (or, conversely, the axion mass, $m_a$, is roughly less than $10^4\\ \\mu \\text{eV}$). The density of axions in the universe, which cannot exceed the relic dark matter density and is a quantity of great interest in axion experiments like ADMX, is a result of the early-universe interplay between cosmological evolution and the axion mass as a function of temperature. The latter quantity is proportional to the second derivative of the QCD free energy with respect to the CP-violating phase, $\\theta$. However, this quantity is generically non-perturbative and previous calculations have only employed instanton models at the high temperatures of interest (roughly 1 GeV). In this and future works, we aim to calculate the temperature-dependent axion mass at small $\\theta$ from first-principle lattice calculations, with controlled statistical and systematic errors. Once calculated, this temperature-dependent axion mass is input for the classical evolution equations of the axion density of the universe. Due to a variety of lattice systematic effects at the very high temperatures required, we perform a calculation of the leading small-$\\theta$ cumulant of the theta vacua on large volume lattices for SU(3) Yang-Mills with high statistics as a first proof of concept, before attempting a full QCD calculation in the future. From these pure glue results, the misalignment mechanism yields the axion mass bound $m_a \\geq (14.6\\pm0.1) \\ \\mu \\text{eV}$ when PQ-breaking occurs after inflation.

  16. Rapid Airplane Parametric Input Design (RAPID)

    NASA Technical Reports Server (NTRS)

    Smith, Robert E.

    1995-01-01

    RAPID is a methodology and software system to define a class of airplane configurations and directly evaluate surface grids, volume grids, and grid sensitivity on and about the configurations. A distinguishing characteristic which separates RAPID from other airplane surface modellers is that the output grids and grid sensitivity are directly applicable in CFD analysis. A small set of design parameters and grid control parameters govern the process which is incorporated into interactive software for 'real time' visual analysis and into batch software for the application of optimization technology. The computed surface grids and volume grids are suitable for a wide range of Computational Fluid Dynamics (CFD) simulation. The general airplane configuration has wing, fuselage, horizontal tail, and vertical tail components. The double-delta wing and tail components are manifested by solving a fourth order partial differential equation (PDE) subject to Dirichlet and Neumann boundary conditions. The design parameters are incorporated into the boundary conditions and therefore govern the shapes of the surfaces. The PDE solution yields a smooth transition between boundaries. Surface grids suitable for CFD calculation are created by establishing an H-type topology about the configuration and incorporating grid spacing functions in the PDE equation for the lifting components and the fuselage definition equations. User specified grid parameters govern the location and degree of grid concentration. A two-block volume grid about a configuration is calculated using the Control Point Form (CPF) technique. The interactive software, which runs on Silicon Graphics IRIS workstations, allows design parameters to be continuously varied and the resulting surface grid to be observed in real time. The batch software computes both the surface and volume grids and also computes the sensitivity of the output grid with respect to the input design parameters by applying the precompiler tool ADIFOR to the grid generation program. The output of ADIFOR is a new source code containing the old code plus expressions for derivatives of specified dependent variables (grid coordinates) with respect to specified independent variables (design parameters). The RAPID methodology and software provide a means of rapidly defining numerical prototypes, grids, and grid sensitivity of a class of airplane configurations. This technology and software is highly useful for CFD research for preliminary design and optimization processes.

  17. Influential input classification in probabilistic multimedia models

    SciTech Connect

    Maddalena, Randy L.; McKone, Thomas E.; Hsieh, Dennis P.H.; Geng, Shu

    1999-05-01

    Monte Carlo analysis is a statistical simulation method that is often used to assess and quantify the outcome variance in complex environmental fate and effects models. Total outcome variance of these models is a function of (1) the uncertainty and/or variability associated with each model input and (2) the sensitivity of the model outcome to changes in the inputs. To propagate variance through a model using Monte Carlo techniques, each variable must be assigned a probability distribution. The validity of these distributions directly influences the accuracy and reliability of the model outcome. To efficiently allocate resources for constructing distributions one should first identify the most influential set of variables in the model. Although existing sensitivity and uncertainty analysis methods can provide a relative ranking of the importance of model inputs, they fail to identify the minimum set of stochastic inputs necessary to sufficiently characterize the outcome variance. In this paper, we describe and demonstrate a novel sensitivity/uncertainty analysis method for assessing the importance of each variable in a multimedia environmental fate model. Our analyses show that for a given scenario, a relatively small number of input variables influence the central tendency of the model and an even smaller set determines the shape of the outcome distribution. For each input, the level of influence depends on the scenario under consideration. This information is useful for developing site specific models and improving our understanding of the processes that have the greatest influence on the variance in outcomes from multimedia models.

  18. Up-scaling of SEBAL derived evapotranspiration maps from Landsat (30 m) to MODIS (250 m) scale

    NASA Astrophysics Data System (ADS)

    Hong, Sung-ho; Hendrickx, Jan M. H.; Borchers, Brian

    2009-05-01

    SummaryRemotely sensed imagery of the Earth's surface via satellite sensors provides information to estimate the spatial distribution of evapotranspiration (ET). The spatial resolution of ET predictions depends on the sensor type and varies from the 30-60 m Landsat scale to the 250-1000 m MODIS scale. Therefore, for an accurate characterization of the regional distribution of ET, scaling transfer between images of different resolutions is important. Scaling transfer includes both up-scaling (aggregation) and down-scaling (disaggregation). In this paper, we address the up-scaling problem. The Surface Energy Balance Algorithm for Land (SEBAL) was used to derive ET maps from Landsat 7 Enhanced Thematic Mapper Plus (ETM+) and Moderate Resolution Imaging Spectroradiometer (MODIS) images. Landsat 7 bands have spatial resolutions of 30-60 m, while MODIS bands have resolutions of 250, 500 and 1000 m. Evaluations were conducted for both "output" and "input" up-scaling procedures, with aggregation accomplished by both simple averaging and nearest neighboring resampling techniques. Output up-scaling consisted of first applying SEBAL and then aggregating the output variable (daily ET). Input up-scaling consisted of aggregating 30 m Landsat pixels of the input variable (radiance) to obtain pixels at 60, 120, 250, 500 and 1000 m before SEBAL was applied. The objectives of this study were first to test the consistency of SEBAL algorithm for Landsat and MODIS satellite images and second to investigate the effect of the four different up-scaling processes on the spatial distribution of ET. We conclude that good agreement exists between SEBAL estimated ET maps directly derived from Landsat 7 and MODIS images. Among the four up-scaling methods the output simple averaging method produced aggregated data and aggregated differences with the most statistically and spatially predictable behavior. The input nearest neighbor method was the least predictable but was still acceptable. Overall, the daily ET maps over the Middle Rio Grande Basin aggregated from Landsat images were in good agreement with ET maps directly derived from MODIS images.

  19. Deformable Model with a Complexity Independent from Image Resolution

    E-print Network

    Paris-Sud XI, Université de

    Deformable Model with a Complexity Independent from Image Resolution J.-O. Lachaud and B. Taton1 which recovers image components with a complexity independent from the resolution of input images-preserving changes in the resolution of input images. Building the metric requires a prior estimation of contour

  20. Development of Purine-Derived 18F-Labeled Pro-drug Tracers for Imaging of MRP1 Activity with PET

    PubMed Central

    2014-01-01

    Multidrug resistance-associated protein 1 (MRP1) is a drug efflux transporter that has been implicated in the pathology of several neurological diseases and is associated with development of multidrug resistance. To enable measurement of MRP1 function in the living brain, a series of 6-halopurines decorated with fluorinated side chains have been synthesized and evaluated as putative pro-drug tracers. The tracers were designed to undergo conjugation with glutathione within the brain and hence form the corresponding MRP1 substrate tracers in situ. 6-Bromo-7-(2-[18F]fluoroethyl)purine showed good brain uptake and rapid metabolic conversion. Dynamic PET imaging demonstrated a marked difference in brain clearance rates between wild-type and mrp1 knockout mice, suggesting that the tracer can allow noninvasive assessment of MRP1 activity in vivo. PMID:24456310

  1. Characterization of the Campbell-Stokes sunshine duration recorder and its ability to derive direct solar radiation by using digital image processing

    NASA Astrophysics Data System (ADS)

    Sanchez-Romero, Alejandro; González, Josep-Abel; Calbó, Josep; Sanchez-Lorenzo, Arturo

    2014-05-01

    The World Meteorological Organization defines the sunshine duration (SD) as the time that, along a given period, direct solar irradiance (DSI) exceeds the threshold level of 120 W/m2. Since the end of 19th century, the Campbell-Stokes sunshine recorder (CSSR) has been the most commonly used instrument used for measuring SD. Due to the large number of long records that exist worldwide, valuable climatic information can be extracted from them. Many authors have used the daily SD (as obtained from the measurement of the length of burn for a given card) to obtain additional information about solar radiation, by using Ångström-Prescott type formulas. Contrarily, the burn width has not been systematically used. Theoretically, the burn is wider (narrower) when the direct insolation is stronger (weaker). The aim of this research is to show the relationship between burn width and DSI, and to prove whether this relationship depends on the type of CSSR and burning card. The research has been carried out in Girona (NE Spain) for a period of two years (from January 2012 to January 2014). Two different models of CSSR (which use different types of cards) and a pyrheliometer from Kipp&Zonen were used to measure SD and DSI, respectively. A semi-automatic method based on image processing of digital scanned images of burnt cards is presented. The method can be summarized in four steps: (i) scan each band on a green background; (ii) apply a digital process to increase the contrast of the burn; (iii) define two/three points in the image, depending of the geometry of the card, to point the center of the day (12.00 TST) on the image and define the trajectory of the sun with 1-minute intervals; and (iv) apply a program to make cross-sections every minute and measure the width of burn. So, after all of this process, we obtain a temporal evolution of the burn width with 1-minute resolution and distinguishing between morning and afternoon. The results show that there is a good correlation between the burn widths obtained from the two types of CSSR. We also observe a quite good correlation with DSI, which is consistent with our hypothesis. However, if we study the threshold value, we obtain a wide range of values that are almost always higher than 120 W/m2, with a significant difference between the morning and afternoon records. Consequently, we consider that the behaviour of cards may also depend on other meteorological variables (temperature, humidity…) affecting the burn. The physical characteristics of the heliograph and of the cardboard from which the bands are made may also have an important role in this relationship. The method was applied to a limited series of cards, but could offer a practical way to exploit the worldwide sets of long-term CSSR data to create long time series of DSI. As there are methods to extract atmospheric aerosol content based on DSI (Linke turbidity factor, Ångström's turbidity coefficient, etc.), SD may become a proxy measurement for turbidity and atmospheric aerosol loading since the late 19th century.

  2. Level 2 processing for the imaging Fourier transform spectrometer GLORIA: derivation and validation of temperature and trace gas volume mixing ratios from calibrated dynamics mode spectra

    NASA Astrophysics Data System (ADS)

    Ungermann, J.; Blank, J.; Dick, M.; Ebersoldt, A.; Friedl-Vallon, F.; Giez, A.; Guggenmoser, T.; Höpfner, M.; Jurkat, T.; Kaufmann, M.; Kaufmann, S.; Kleinert, A.; Krämer, M.; Latzko, T.; Oelhaf, H.; Olchewski, F.; Preusse, P.; Rolf, C.; Schillings, J.; Suminska-Ebersoldt, O.; Tan, V.; Thomas, N.; Voigt, C.; Zahn, A.; Zöger, M.; Riese, M.

    2015-06-01

    The Gimballed Limb Observer for Radiance Imaging of the Atmosphere (GLORIA) is an airborne infrared limb imager combining a two-dimensional infrared detector with a Fourier transform spectrometer. It was operated aboard the new German Gulfstream G550 High Altitude LOng Range (HALO) research aircraft during the Transport And Composition in the upper Troposphere/lowermost Stratosphere (TACTS) and Earth System Model Validation (ESMVAL) campaigns in summer 2012. This paper describes the retrieval of temperature and trace gas (H2O, O3, HNO3) volume mixing ratios from GLORIA dynamics mode spectra that are spectrally sampled every 0.625 cm-1. A total of 26 integrated spectral windows are employed in a joint fit to retrieve seven targets using consecutively a fast and an accurate tabulated radiative transfer model. Typical diagnostic quantities are provided including effects of uncertainties in the calibration and horizontal resolution along the line of sight. Simultaneous in situ observations by the Basic Halo Measurement and Sensor System (BAHAMAS), the Fast In-situ Stratospheric Hygrometer (FISH), an ozone detector named Fairo, and the Atmospheric chemical Ionization Mass Spectrometer (AIMS) allow a validation of retrieved values for three flights in the upper troposphere/lowermost stratosphere region spanning polar and sub-tropical latitudes. A high correlation is achieved between the remote sensing and the in situ trace gas data, and discrepancies can to a large extent be attributed to differences in the probed air masses caused by different sampling characteristics of the instruments. This 1-D processing of GLORIA dynamics mode spectra provides the basis for future tomographic inversions from circular and linear flight paths to better understand selected dynamical processes of the upper troposphere and lowermost stratosphere.

  3. Image processing and recognition for biological images

    PubMed Central

    Uchida, Seiichi

    2013-01-01

    This paper reviews image processing and pattern recognition techniques, which will be useful to analyze bioimages. Although this paper does not provide their technical details, it will be possible to grasp their main tasks and typical tools to handle the tasks. Image processing is a large research area to improve the visibility of an input image and acquire some valuable information from it. As the main tasks of image processing, this paper introduces gray-level transformation, binarization, image filtering, image segmentation, visual object tracking, optical flow and image registration. Image pattern recognition is the technique to classify an input image into one of the predefined classes and also has a large research area. This paper overviews its two main modules, that is, feature extraction module and classification module. Throughout the paper, it will be emphasized that bioimage is a very difficult target for even state-of-the-art image processing and pattern recognition techniques due to noises, deformations, etc. This paper is expected to be one tutorial guide to bridge biology and image processing researchers for their further collaboration to tackle such a difficult target. PMID:23560739

  4. Validation of the 3D biogeochemical model MIRO&CO with field nutrient and phytoplankton data and MERIS-derived surface chlorophyll a images

    NASA Astrophysics Data System (ADS)

    Lacroix, Geneviève; Ruddick, Kevin; Park, Youngje; Gypens, Nathalie; Lancelot, Christiane

    2007-01-01

    This paper presents results obtained with MIRO&CO-3D, a biogeochemical model dedicated to the study of eutrophication and applied to the Channel and Southern Bight of the North Sea (48.5°N-52.5°N). The model results from coupling of the COHERENS-3D hydrodynamic model and the biogeochemical model MIRO, which was previously calibrated in a multi-box implementation. MIRO&CO-3D is run to simulate the annual cycle of inorganic and organic carbon and nutrients (nitrogen, phosphorus and silica), phytoplankton (diatoms, nanoflagellates and Phaeocystis), bacteria and zooplankton (microzooplankton and copepods) with realistic forcing (meteorological conditions and river loads) for the period 1991-2003. Model validation is first shown by comparing time series of model concentrations of nutrients, chlorophyll a, diatom and Phaeocystis with in situ data from station 330 (51°26.00'N, 2°48.50'E) located in the centre of the Belgian coastal zone. This comparison shows the model's ability to represent the seasonal dynamics of nutrients and phytoplankton in Belgian waters. However the model fails to simulate correctly the dissolved silica cycle, especially during the beginning of spring, due to the late onset (in the model) of the early spring diatom bloom. As a general trend the chlorophyll a spring maximum is underestimated in simulations. A comparison between the seasonal average of surface winter nutrients and spring chlorophyll a concentrations simulated with in situ data for different stations is used to assess the accuracy of the simulated spatial distribution. At a seasonal scale, the spatial distribution of surface winter nutrients is in general well reproduced by the model with nevertheless a small overestimation for a few stations close to the Rhine/Meuse mouth and a tendency to underestimation in the coastal zone from Belgium to France. PO 4 was simulated best; silica was simulated with less success. Spring chlorophyll a concentration is in general underestimated by the model. The accuracy of the simulated phytoplankton spatial distribution is further evaluated by comparing simulated surface chlorophyll a with that derived from the satellite sensor MERIS for the year 2003. Reasonable agreement is found between simulated and satellite-derived regions of high chlorophyll a with nevertheless discrepancies close to the boundaries.

  5. Radiometric modeling of cavernous targets to assist in the determination of absolute temperature for input to process models

    NASA Astrophysics Data System (ADS)

    Montanaro, Matthew; Salvaggio, Carl; Brown, Scott D.; Messinger, David W.; Goodenough, Adam A.; Garrett, Alfred J.; Villa-Aleman, Eliel

    2007-04-01

    Determining the temperature of an internal surface within cavernous targets, such as the interior wall of a mechanical draft cooling tower, from remotely sensed imagery is important for many surveillance applications that provide input to process models. The surface leaving radiance from an observed target is a combination of the self-emitted radiance and the reflected background radiance. The self-emitted radiance component is a function of the temperature-dependent blackbody radiation and the view-dependent directional emissivity. The reflected background radiance component depends on the bidirectional reflectance distribution function (BRDF) of the surface, the incident radiance from surrounding sources, and the BRDF for each of these background sources. Inside a cavity, the background radiance emanating from any of the multiple internal surfaces will be a combination of the self-emitted and reflected energy from the other internal surfaces as well as the downwelling sky radiance. This scenario provides for a complex radiometric inversion problem in order to arrive at the absolute temperature of any of these internal surfaces. The cavernous target has often been assumed to be a blackbody, but in field experiments it has been determined that this assumption does not always provide an accurate surface temperature. The Digital Imaging and Remote Sensing Image Generation (DIRSIG) modeling tool is being used to represent a cavity target. The model demonstrates the dependence of the radiance reaching the sensor on the emissivity of the internal surfaces and the multiple internal interactions between all the surfaces that make up the overall target. The cavity model is extended to a detailed model of a mechanical draft cooling tower. The predictions of derived temperature from this model are compared to those derived from actual infrared imagery collected with a helicopter-based broadband infrared imaging system collected over an operating tower located at the Savannah River National Laboratory site.

  6. Imaging plasmodesmata

    Microsoft Academic Search

    Karen Bell; Karl Oparka

    2011-01-01

    At only 50 nm in diameter, plasmodesmata (PD) are below the limit of resolution of conventional light microscopy. Consequently,\\u000a much of our current interpretation of the substructure of PD is derived from transmission electron microscopy. However, PD\\u000a can be imaged with alternative techniques, including field emission scanning electron microscopy and ‘super-resolution’ imaging\\u000a approaches such as 3D-structured illumination microscopy. This review considers

  7. An evaluation of the variability of tumor-shape definition derived by experienced observers from CT images of supraglottic carcinomas (ACRIN protocol 6658)

    SciTech Connect

    Cooper, Jay S. [Department of Radiation Oncology, Maimonides Medical Center, Brooklyn, NY (United States)]. E-mail: jcooper@maimonidesmed.org; Mukherji, Suresh K. [Department of Radiology, University of Michigan Health System, Ann Arbor, MI (United States); Department of Otolaryngology Head Neck Surgery, University of Michigan Health System, Ann Arbor, MI (United States); Toledano, Alicia Y. [Center for Statistical Sciences, Brown University, Providence, RI (United States); Beldon, Clifford [Department of Radiology, State University of New York, Albany Medical School, Albany, NY (United States); Schmalfuss, Ilona M. [Department of Radiology, University of Florida School of Medicine, Gainesville, FL (United States); Amdur, Robert [Department of Radiation Oncology, University of Florida School of Medicine, Gainesville, FL (United States); Sailer, Scott [Department of Radiation Oncology, University of North Carolina School of Medicine, Chapel Hill, NC (United States); Loevner, Laurie A. [Department of Radiology, University of Pennsylvania School of Medicine, Philadelphia, PA (United States); Kousouboris, Phil [Department of Radiology, Bryn Mawr Hospital, Bryn Mawr, PA (United States); Ang, K. Kian [Department of Radiation Oncology, M. D. Anderson Cancer Center, Houston, TX (United States); Cormack, Jean [Center for Statistical Sciences, Brown University, Providence, RI (United States); Sicks, JoRean M.S. [Center for Statistical Sciences, Brown University, Providence, RI (United States)

    2007-03-15

    Purpose: Accurate target definition is considered essential for sophisticated, image-guided radiation therapy; however, relatively little information has been reported that measures our ability to identify the precise shape of targets accurately. We decided to assess the manner in which eight 'experts' interpreted the size and shape of tumors based on 'real-life' contrast-enhanced computed tomographic (CT) scans. Methods and Materials: Four neuroradiologists and four radiation oncologists (the authors) with considerable experience and presumed expertise in treating head-and-neck tumors independently contoured, slice-by-slice, his/her interpretation of the precise gross tumor volume (GTV) on each of 20 sets of CT scans taken from 20 patients who previously were enrolled in Radiation Therapy Oncology Group protocol 91-11. Results: The average proportion of overlap (i.e., the degree of agreement) was 0.532 (95% confidence interval 0.457 to 0.606). There was a slight tendency for the proportion of overlap to increase with increasing average GTV. Conclusions: Our work suggests that estimation of tumor shape currently is imprecise, even for experienced physicians. In consequence, there appears to be a practical limit to the current trend of smaller fields and tighter margins.

  8. Stability Analysis of Networked Control Systems with Unknown Inputs

    E-print Network

    Sun, Dengfeng

    Stability Analysis of Networked Control Systems with Unknown Inputs Ahmad F Taha, Ahmed Elmahdi# , Jitesh H. Panchal and Dengfeng Sun Abstract-- Unknown Input Observers (UIO) use the known plant's inputs and outputs to generate state estimates for plants with unknown inputs. In many cases, the UIO's inputs

  9. Computerized tomography using video recorded fluoroscopic images

    NASA Technical Reports Server (NTRS)

    Kak, A. C.; Jakowatz, C. V., Jr.; Baily, N. A.; Keller, R. A.

    1975-01-01

    A computerized tomographic imaging system is examined which employs video-recorded fluoroscopic images as input data. By hooking the video recorder to a digital computer through a suitable interface, such a system permits very rapid construction of tomograms.

  10. Interactive specification and acquisition of depth from single images

    E-print Network

    Chen, Max, 1977-

    2001-01-01

    We describe a system for interactively acquiring depth for an image-based representation consisting of a single input image. We use layers of images with depth to represent the scene. Unlike traditional 3D modeling and ...

  11. Decontextualized language input and preschoolers' vocabulary development.

    PubMed

    Rowe, Meredith L

    2013-11-01

    This article discusses the importance of using decontextualized language, or language that is removed from the here and now including pretend, narrative, and explanatory talk, with preschool children. The literature on parents' use of decontextualized language is reviewed and results of a longitudinal study of parent decontextualized language input in relation to child vocabulary development are explained. The main findings are that parents who provide their preschool children with more explanations and narrative utterances about past or future events in the input have children with larger vocabularies 1?year later, even with quantity of parent input and child prior vocabulary skill controlled. Recommendations for how to engage children in decontextualized language conversations are provided. PMID:24297618

  12. Computer Generated Inputs for NMIS Processor Verification

    SciTech Connect

    J. A. Mullens; J. E. Breeding; J. A. McEvers; R. W. Wysor; L. G. Chiang; J. R. Lenarduzzi; J. T. Mihalczo; J. K. Mattingly

    2001-06-29

    Proper operation of the Nuclear Identification Materials System (NMIS) processor can be verified using computer-generated inputs [BIST (Built-In-Self-Test)] at the digital inputs. Preselected sequences of input pulses to all channels with known correlation functions are compared to the output of the processor. These types of verifications have been utilized in NMIS type correlation processors at the Oak Ridge National Laboratory since 1984. The use of this test confirmed a malfunction in a NMIS processor at the All-Russian Scientific Research Institute of Experimental Physics (VNIIEF) in 1998. The NMIS processor boards were returned to the U.S. for repair and subsequently used in NMIS passive and active measurements with Pu at VNIIEF in 1999.

  13. Polymorph: Morphing Among Multiple Images

    Microsoft Academic Search

    Seungyong Lee; George Wolberg; Sung Yong Shin

    1998-01-01

    Abstract: this article, we present a general framework for polymorphingby extending the traditional image morphingparadigm that applies to twoimages. We formulate eachinput image as a vertex of an (n - 1)-dimensional simplex,where n equals the number of input images. Notethat an (n - 1)-dimensional simplex is a convex polyhedronhaving n vertices in (n - 1)-dimensional space, suchas a triangle in

  14. Parameterized sketches from stereo images

    Microsoft Academic Search

    Danijela Markovic; Efstathios Stavrakis; Margrit Gelautz

    2005-01-01

    In this paper we present an algorithm to automatically generate sketches from stereo image pairs. Stereo analysis is initially performed on the input stereo pair to estimate a dense depth map. An Edge Combination image is computed by localising object contour edges, as indicated by the depth map, within the intensity reference image. We then approximate these pixel-represented contours by

  15. Comparison of Placido disc and Scheimpflug image-derived topography-guided excimer laser surface normalization combined with higher fluence CXL: the Athens Protocol, in progressive keratoconus

    PubMed Central

    Anastasios, John Kanellopoulos; Asimellis, George

    2013-01-01

    Background The purpose of this study was to compare the safety and efficacy of two alternative corneal topography data sources used in topography-guided excimer laser normalization, combined with corneal collagen cross-linking in the management of keratoconus using the Athens protocol, ie, a Placido disc imaging device and a Scheimpflug imaging device. Methods A total of 181 consecutive patients with keratoconus who underwent the Athens protocol between 2008 and 2011 were studied preoperatively and at months 1, 3, 6, and 12 postoperatively for visual acuity, keratometry, and anterior surface corneal irregularity indices. Two groups were formed, depending on the primary source used for topoguided photoablation, ie, group A (Placido disc) and group B (Scheimpflug rotating camera). One-year changes in visual acuity, keratometry, and seven anterior surface corneal irregularity indices were studied in each group. Results Changes in visual acuity, expressed as the difference between postoperative and preoperative corrected distance visual acuity were +0.12 ± 0.20 (range +0.60 to ?0.45) for group A and +0.19 ± 0.20 (range +0.75 to ?0.30) for group B. In group A, K1 (flat keratometry) changed from 45.202 ± 3.782 D to 43.022 ± 3.819 D, indicating a flattening of ?2.18 D, and K2 (steep keratometry) changed from 48.670 ± 4.066 D to 45.865 ± 4.794 D, indicating a flattening of ?2.805 D. In group B, K1 (flat keratometry) changed from 46.213 ± 4.082 D to 43.190 ± 4.398 D, indicating a flattening of ?3.023 D, and K2 (steep keratometry) changed from 50.774 ± 5.210 D to 46.380 ± 5.006 D, indicating a flattening of ?4.394 D. For group A, the index of surface variance decreased to ?5.07% and the index of height decentration to ?26.81%. In group B, the index of surface variance decreased to ?18.35% and the index of height decentration to ?39.03%. These reductions indicate that the corneal surface became less irregular (index of surface variance) and the “cone” flatter and more central (index of height decentration) postoperatively. Conclusion Of the two sources of primary corneal data, the Scheimpflug rotating camera (Oculyzer™) for topography-guided normalization treatment with the WaveLight excimer laser platform appeared to provide more statistically significant improvement than the Placido disc topographer (Topolyzer™). Overall, the Athens protocol, aiming both to halt progression of keratoconic ectasia and to improve corneal topometry and visual performance, produced safe and satisfactory refractive, keratometric, and topometric results. The observed changes in visual acuity, along with keratometric flattening and topometric improvement, are suggestive of overall postoperative improvement. PMID:23901251

  16. A Lyapunov Approach to Cascade Interconnection of Integral Input-to-State Stable Systems

    Microsoft Academic Search

    Hiroshi Ito

    2010-01-01

    This technical note deals with the stability of cascade interconnection of integral input-to-state (iISS) time-varying systems. A new technique to construct smooth Lyapunov functions of cascaded systems is proposed. From the construction, sufficient conditions for internal stability and stability with respect to external signals are derived. One of the derived conditions is a trade-off between slower convergence of the driving

  17. Inner Heliospheric Evolution of a "Stealth" CME Derived from Multi-view Imaging and Multipoint in Situ observations. I. Propagation to 1 AU

    NASA Astrophysics Data System (ADS)

    Nieves-Chinchilla, T.; Vourlidas, A.; Stenborg, G.; Savani, N. P.; Koval, A.; Szabo, A.; Jian, L. K.

    2013-12-01

    Coronal mass ejections (CMEs) are the main driver of space weather. Therefore, a precise forecasting of their likely geo-effectiveness relies on an accurate tracking of their morphological and kinematical evolution throughout the interplanetary medium. However, single viewpoint observations require many assumptions to model the development of the features of CMEs. The most common hypotheses were those of radial propagation and self-similar expansion. The use of different viewpoints shows that, at least for some cases, those assumptions are no longer valid. From radial propagation, typical attributes that can now be confirmed to exist are over-expansion and/or rotation along the propagation axis. Understanding the 3D development and evolution of the CME features will help to establish the connection between remote and in situ observations, and hence help forecast space weather. We present an analysis of the morphological and kinematical evolution of a STEREO-B-directed CME on 2009 August 25-27. By means of a comprehensive analysis of remote imaging observations provided by the SOHO, STEREO, and SDO missions, and in situ measurements recorded by Wind, ACE, and MESSENGER, we prove in this paper that the event exhibits signatures of deflection, which are usually associated with changes in the direction of propagation and/or also with rotation. The interaction with other magnetic obstacles could act as a catalyst of deflection or rotation effects. We also propose a method to investigate the change of the CME tilt from the analysis of height-time direct measurements. If this method is validated in further work, it may have important implications for space weather studies because it will allow for inference of the interplanetary counterpart of the CME's orientation.

  18. Inner heliospheric evolution of a 'STEALTH' CME derived from multi-view imaging and multipoint in situ observations. I. Propagation to 1 AU

    SciTech Connect

    Nieves-Chinchilla, T. [Catholic University of America, Washington, DC 20064 (United States); Vourlidas, A. [Space Science Division, Naval Research Laboratory, Washington, DC 20375 (United States); Stenborg, G. [George Mason University, College of Science, Fairfax, VA 22030 (United States); Savani, N. P.; Koval, A.; Szabo, A.; Jian, L. K., E-mail: Teresa.Nieves@nasa.gov [NASA Goddard Space Flight Center, Greenbelt, MD 20770 (United States)

    2013-12-10

    Coronal mass ejections (CMEs) are the main driver of space weather. Therefore, a precise forecasting of their likely geo-effectiveness relies on an accurate tracking of their morphological and kinematical evolution throughout the interplanetary medium. However, single viewpoint observations require many assumptions to model the development of the features of CMEs. The most common hypotheses were those of radial propagation and self-similar expansion. The use of different viewpoints shows that, at least for some cases, those assumptions are no longer valid. From radial propagation, typical attributes that can now be confirmed to exist are over-expansion and/or rotation along the propagation axis. Understanding the 3D development and evolution of the CME features will help to establish the connection between remote and in situ observations, and hence help forecast space weather. We present an analysis of the morphological and kinematical evolution of a STEREO-B-directed CME on 2009 August 25-27. By means of a comprehensive analysis of remote imaging observations provided by the SOHO, STEREO, and SDO missions, and in situ measurements recorded by Wind, ACE, and MESSENGER, we prove in this paper that the event exhibits signatures of deflection, which are usually associated with changes in the direction of propagation and/or also with rotation. The interaction with other magnetic obstacles could act as a catalyst of deflection or rotation effects. We also propose a method to investigate the change of the CME tilt from the analysis of height-time direct measurements. If this method is validated in further work, it may have important implications for space weather studies because it will allow for inference of the interplanetary counterpart of the CME's orientation.

  19. Apple Image Processing Educator

    NASA Technical Reports Server (NTRS)

    Gunther, F. J.

    1981-01-01

    A software system design is proposed and demonstrated with pilot-project software. The system permits the Apple II microcomputer to be used for personalized computer-assisted instruction in the digital image processing of LANDSAT images. The programs provide data input, menu selection, graphic and hard-copy displays, and both general and detailed instructions. The pilot-project results are considered to be successful indicators of the capabilities and limits of microcomputers for digital image processing education.

  20. Replenishment of magma chambers by light inputs

    NASA Astrophysics Data System (ADS)

    Huppert, Herbert E.; Sparks, R. Stephen J.; Whitehead, John A.; Hallworth, Mark A.

    1986-05-01

    Magma chambers, particularly those of basaltic composition, are often replenished by an influx of magma whose density is less than that of the resident magma. This paper describes the fundamental fluid mechanics involved in the replenishment by light inputs. If ? denotes the uniform density of the resident magma and ? — ?? that of the input, the situation is described by the reduced gravity g' = g??/?, the volume flux Q, and the viscosities of the resident and input magmas ?e and ?i, respectively. The (nondimensional) Reynolds numbers, Ree = (g'Q3)1/5/?e and Rei = (g'Q3)1/5/?i and chamber geometry then completely specify the system. For sufficiently low values of the two Reynolds numbers (each less than approximately 10), the input rises as a laminar conduit. For larger values of the Reynolds numbers, the conduit may break down and exhibit either a varicose or a meander instability and entrain some resident magma. At still larger Reynolds numbers, the flow will become quite unsteady and finally turbulent. The values of the Reynolds numbers at which these transitions occur have been documented by a series of experiments with water, glycerine, and corn syrup. If the input rises as a turbulent plume, significant entrainment of the resident magma can take place. The final spatial distribution of the mixed magma depends on the geometry of the chamber. If the chamber is much wider than it is high, the mixed magma forms a compositionally stratified region between the roof and a sharp front above uncontaminated magma. In the other geometrical extreme, the input magma is mixed with almost all of the resident magma. If the density of the resident magma is already stratified, the input plume may penetrate only part way into the chamber, even though its initial density is less than that of the lowest density resident magma. The plume will then intrude horizontally and form a hybrid layer at an intermediate depth. This provides a mechanism for preventing even primitive basaltic magmas of minimum density from erupting at the surface. By conducting an experiment using aqueous solutions, we show that entrainment can lead to crystallization of the magma in the input plume by making it locally supersaturated. All these effects are discussed and illustrated by photographs of laboratory experiments.

  1. An update of input instructions to TEMOD

    NASA Technical Reports Server (NTRS)

    1973-01-01

    The theory and operation of a FORTRAN 4 computer code, designated as TEMOD, used to calcuate tubular thermoelectric generator performance is described in WANL-TME-1906. The original version of TEMOD was developed in 1969. A description is given of additions to the mathematical model and an update of the input instructions to the code. Although the basic mathematical model described in WANL-TME-1906 has remained unchanged, a substantial number of input/output options were added to allow completion of module performance parametrics as required in support of the compact thermoelectric converter system technology program.

  2. Motion-gated acquisition for in vivo optical imaging

    PubMed Central

    Gioux, Sylvain; Ashitate, Yoshitomo; Hutteman, Merlijn; Frangioni, John V.

    2009-01-01

    Wide-field continuous wave fluorescence imaging, fluorescence lifetime imaging, frequency domain photon migration, and spatially modulated imaging have the potential to provide quantitative measurements in vivo. However, most of these techniques have not yet been successfully translated to the clinic due to challenging environmental constraints. In many circumstances, cardiac and respiratory motion greatly impair image quality and?or quantitative processing. To address this fundamental problem, we have developed a low-cost, field-programmable gate array–based, hardware-only gating device that delivers a phase-locked acquisition window of arbitrary delay and width that is derived from an unlimited number of pseudo-periodic and nonperiodic input signals. All device features can be controlled manually or via USB serial commands. The working range of the device spans the extremes of mouse electrocardiogram (1000 beats per minute) to human respiration (4 breaths per minute), with timing resolution ?0.06%, and jitter ?0.008%, of the input signal period. We demonstrate the performance of the gating device, including dramatic improvements in quantitative measurements, in vitro using a motion simulator and in vivo using near-infrared fluorescence angiography of beating pig heart. This gating device should help to enable the clinical translation of promising new optical imaging technologies. PMID:20059276

  3. Visual stimulation switches the polarity of excitatory input to starburst amacrine cells.

    PubMed

    Vlasits, Anna L; Bos, Rémi; Morrie, Ryan D; Fortuny, Cécile; Flannery, John G; Feller, Marla B; Rivlin-Etzion, Michal

    2014-09-01

    Direction-selective ganglion cells (DSGCs) are tuned to motion in one direction. Starburst amacrine cells (SACs) are thought to mediate this direction selectivity through precise anatomical wiring to DSGCs. Nevertheless, we previously found that visual adaptation can reverse DSGCs's directional tuning, overcoming the circuit anatomy. Here we explore the role of SACs in the generation and adaptation of direction selectivity. First, using pharmacogenetics and two-photon calcium imaging, we validate that SACs are necessary for direction selectivity. Next, we demonstrate that exposure to an adaptive stimulus dramatically alters SACs' synaptic inputs. Specifically, after visual adaptation, On-SACs lose their excitatory input during light onset but gain an excitatory input during light offset. Our data suggest that visual stimulation alters the interactions between rod- and cone-mediated inputs that converge on the terminals of On-cone BCs. These results demonstrate how the sensory environment can modify computations performed by anatomically defined neuronal circuits. PMID:25155960

  4. Illumination normalization with time-dependent intrinsic images for video surveillance.

    PubMed

    Matsushita, Yasuyuki; Nishino, Ko; Ikeuchi, Katsushi; Sakauchi, Masao

    2004-10-01

    Variation in illumination conditions caused by weather, time of day, etc., makes the task difficult when building video surveillance systems of real world scenes. Especially, cast shadows produce troublesome effects, typically for object tracking from a fixed viewpoint, since it yields appearance variations of objects depending on whether they are inside or outside the shadow. In this paper, we handle such appearance variations by removing shadows in the image sequence. This can be considered as a preprocessing stage which leads to robust video surveillance. To achieve this, we propose a framework based on the idea of intrinsic images. Unlike previous methods of deriving intrinsic images, we derive time-varying reflectance images and corresponding illumination images from a sequence of images instead of assuming a single reflectance image. Using obtained illumination images, we normalize the input image sequence in terms of incident lighting distribution to eliminate shadowing effects. We also propose an illumination normalization scheme which can potentially run in real time, utilizing the illumination eigenspace, which captures the illumination variation due to weather, time of day, etc., and a shadow interpolation method based on shadow hulls. This paper describes the theory of the framework with simulation results and shows its effectiveness with object tracking results on real scene data sets. PMID:15641720

  5. Input-based Language Modelling in the Design of High Performance Text Input Techniques

    E-print Network

    MacKenzie, Scott

    . It is like a built-in checksum that is automatically included in every English phrase. Without the checksum-33014 University of Tampere {will, smackenzie}@acm.org Tampere, Finland Abstract We present a critique of language-based modelling for text input research, and propose an alternative input- based approach. Current

  6. Rhenium analogues of promising renal imaging agents with a [99mTc(CO)3]+ core bound to cysteine-derived dipeptides, including lanthionine.

    PubMed

    He, Haiyang; Lipowska, Malgorzata; Xu, Xiaolong; Taylor, Andrew T; Marzilli, Luigi G

    2007-04-16

    The coordination chemistry of lanthionine (LANH2) and cystathionine (CSTH2) dipeptides, which respectively consist of two cysteines and one cysteine and one homocysteine linked by a thioether bridge, is almost unstudied. Recently for fac-[99mTc(CO)3(LAN)]- isomers, the first small 99mTc(CO)3 agents evaluated in humans were found to give excellent renal images and to have a high specificity for renal excretion. Herein we report the synthesis and characterization of Re complexes useful for interpreting the nature of tracer 99mTc radiopharmaceuticals. Treatment of [Re(CO)3(H2O)3]OTf with commercially available LANH2 (a mixture of meso (d,l) and chiral (dd,ll) isomers) gave three HPLC peaks, 1A, 1B, and 1C, but treatment with CSTH2 (l,l isomer) gave one major product, Re(CO)3(CSTH) (2). Crystalline Re(CO)3(LANH) products were best obtained with synthetic LANH2, richer in meso or chiral isomers. X-ray crystallography showed that these dipeptides coordinate as tridentate N2S-bound ligands with two dangling carboxyls. The LANH ligand is meso in 1A and 1C and chiral in 1B. While 1A (kinetically favored) is stable at ambient temperature for days, it converted into 1C (thermodynamically favored) at 100 degrees C; after 6 h, equilibrium was reached at a 1A:1C ratio of 1:2 at pH 8. The structures provide a rationale for this behavior and for the fact that 1A and 1C have simple NMR spectra. This simplicity results from fluxional interchange between an enantiomer with both chelate rings having the same delta pucker and an enantiomer with both chelate rings having the same lambda pucker. Agents with the [99mTc(CO)3]+ core and N2S ligands show promise of becoming an important class of 99mTc radiopharmaceuticals. The chemistry of Re analogues with these ligands, such as the LAN2- complexes reported here, provides a useful background for designing new small agents and also tagged large agents because two uncoordinated carboxyl groups are available for conjugation with biological molecules such as proteins. PMID:17375908

  7. Dual isotope simultaneous imaging to evaluate the effects of intracoronary bone marrow-derived mesenchymal stem cells on perfusion and metabolism in canines with acute myocardial infarction

    PubMed Central

    HAO, LINJUN; HAO, JIN; FANG, WEI; HAN, CHUNLEI; ZHANG, KAIXIU; WANG, XUEMEI

    2015-01-01

    Stem cell therapy on acute myocardial infarction (AMI) has been performed for over a decade. In the present study, cardiac perfusion, metabolism and function in dogs with AMI treated by intracoronary injection of bone marrow-derived mesenchymal stem cells (MSCs) were evaluated by dual isotope simultaneous acquisition (DISA) of single positron emission computed tomography (SPECT). Dogs (n=12, 20–30 kg) were randomly assigned to two groups: A graft study (n=6) and control group (n=6). Bone marrow mesenchymal aspirate was collected 3 weeks before surgical procedure. Stem cells were induced by 5-azacytidine for differentiation into myocytes. The dog AMI model was produced by blocking the blood stream at 1/3 of the distinct left anterior descending coronary artery for 90 min. For dogs in the grafting group, MSCs were transplanted by intracoronary injection, and for the control group, 0.9% NaCl was injected instead. At 1 and 10 weeks after MSCs were grafted, respectively, SPECT DISA was performed for each dog in the two groups with 99mTc-SPECT MIBI (925 MBq) and 18F-FDG (222 MBq) for evaluation of myocardial perfusion and metabolism. After the dogs were sacrificed, heart tissue was stained by myocyte-specific antibodies for newborn vessels, troponin T and bromodeoxyuridine (BrdU). Following induction by 5-azacytidine, the morphological features with colony formation, microfilament, as well as atrial granules and positive stainings of ?-actinin, myosin and troponin I demonstrated strongly that the MSCs differentiated into myocytes. The number of viable myocardial segments was 10 in the grafting group, which was significantly greater compared with the control group. The ejection fraction of the infarcted left ventricle (LVEF,%) increased from 53.80±9.58 to 70.00±7.52 (change, 16.20±2.93) at 1 and 10 weeks after MSCs engraftment, whilst in the control group, LVEF was 50.50±8.02 and 56.50±7.24 (change, 5.50±2.69), respectively. The LVEF difference was statistically significant (P<0.05) between the graft and control groups. Furthermore, immunostaining of all the myocyte-specific antibodies (for newly born vessels, troponin T and BrdU) was positive. In conclusion, direct intracoronary injection of bone marrow MSCs into injured myocardium in the experimental dog AMI model can significantly improve cardiac function with new vessel formation and myocyte-specific biomarker expression, and in particular, the present study further shows that DISA SPECT can be used for the assessment of stem cell transplantation in the heart. PMID:26171146

  8. Quantum Hilbert Image Scrambling

    NASA Astrophysics Data System (ADS)

    Jiang, Nan; Wang, Luo; Wu, Wen-Ya

    2014-07-01

    Analogies between quantum image processing (QIP) and classical one indicate that quantum image scrambling (QIS), as important as quantum Fourier transform (QFT), quantum wavelet transform (QWT) and etc., should be proposed to promote QIP. Image scrambling technology is commonly used to transform a meaningful image into a disordered image by permutating the pixels into new positions. Although image scrambling on classical computers has been widely studied, we know much less about QIS. In this paper, the Hilbert image scrambling algorithm, which is commonly used in classical image processing, is carried out in quantum computer by giving the scrambling quantum circuits. First, a modified recursive generation algorithm of Hilbert scanning matrix is given. Then based on the flexible representation of quantum images, the Hilbert scrambling quantum circuits, which are recursive and progressively layered, is proposed. Theoretical analysis indicates that the network complexity scales squarely with the size of the circuit's input n.

  9. Representation of Odorants by Receptor Neuron Input to the Mouse Olfactory Bulb

    Microsoft Academic Search

    Matt Wachowiak; Lawrence B. Cohen

    2001-01-01

    To visualize odorant representations by receptor neuron input to the mouse olfactory bulb, we loaded receptor neurons with calcium-sensitive dye and imaged odorant-evoked responses from their axon terminals. Fluorescence increases reflected activation of receptor neuron populations converging onto individual glomeruli. We report several findings. First, five glomeruli were identifiable across animals based on their location and odorant responsiveness; all five

  10. Adaptive control of input field to achieve desired output intensity profile in

    E-print Network

    Kahn, Joseph M.

    or adaptive optics; (110.2350) Fiber optics imaging; (170.4520) Optical confinement and manipulation. Dholakia, "In-fiber common-path optical coherence tomography using a conical-tip fiber," Opt. Express 17Adaptive control of input field to achieve desired output intensity profile in multimode fiber

  11. Understanding the Impact of Charcoal Inputs to Soils and Sediments on Conventional Geochemical Markers

    Microsoft Academic Search

    L. Kuo; P. Louchouarn; B. Herbert

    2008-01-01

    Chars\\/charcoals are solid combustion residues derived from biomass burning. They represent one of the major classes in the pyrogenic organic residues, the so-called black carbon (BC), and have highly heterogeneous nature due to the highly variable combustion conditions during biomass burning. More and more attention has been given to characterize and quantify the inputs of charcoals to different environmental compartments

  12. Influence of streamside vegetation on inputs of terrestrial invertebrates to salmonid food webs

    E-print Network

    Wagner, Diane

    Influence of streamside vegetation on inputs of terrestrial invertebrates to salmonid food webs J, and spawning migrations. We examined the contribution of terrestrially derived invertebrates (TI) to juvenile of invertebrate mass averaged across all sites; no significant differences associated with location (plant

  13. Chandrasekhar equations for infinite dimensional systems. Part 2: Unbounded input and output case

    NASA Technical Reports Server (NTRS)

    Ito, Kazufumi; Powers, Robert K.

    1987-01-01

    A set of equations known as Chandrasekhar equations arising in the linear quadratic optimal control problem is considered. In this paper, we consider the linear time-invariant system defined in Hilbert spaces involving unbounded input and output operators. For a general class of such systems, the Chandrasekhar equations are derived and the existence, uniqueness, and regularity of the results of their solutions established.

  14. Investigation of Effects of Varying Model Inputs on Mercury Deposition Estimates in the Southwest US

    EPA Science Inventory

    The Community Multiscale Air Quality (CMAQ) model version 4.7.1 was used to simulate mercury wet and dry deposition for a domain covering the continental United States (US). The simulations used MM5-derived meteorological input fields and the US Environmental Protection Agency (E...

  15. Optimum control of N-input K-output matrix converters

    Microsoft Academic Search

    P. Tenti; L. Malesani; L. Rossetto

    1992-01-01

    Significant developments of the general optimum control theory presented in a previous paper by the authors (1988) are discussed for the specific case of multiphase matrix converters. Results hold, regardless of system configuration, input and output voltage waveforms, and loads. Applications to the most practical converter structures are illustrated, and implementation criteria of the optimum control method are derived. Simulated

  16. DO MODEL UNCERTAINTY WITH CORRELATED INPUTS

    EPA Science Inventory

    The effect of correlation among the input parameters and variables on the output uncertainty of the Streeter-Phelps water quality model is examined. hree uncertainty analysis techniques are used: sensitivity analysis, first-order error analysis, and Monte Carlo simulation. odifie...

  17. Student Input in College Decision Making

    ERIC Educational Resources Information Center

    Schwartz, Celeste M.; Craig, Emory M.; Trzeciak, Jeff; Little, Julie K.; Diaz, Veronica

    2008-01-01

    Engaging students in making decisions, especially those that directly impact student life, benefits the institution and the students themselves. Students are often asked to evaluate faculty, courses, campus services, and their overall college experience, but their opinions are more rarely solicited for input about new institutional initiatives.…

  18. Input Pulse Response in Nonlinear Transmission Line

    Microsoft Academic Search

    Ian M. Rittersdorf; David M. French; Michael Johnson; Y. Y. Lau; Ronald M. Gilgenbach; Donald Shiffler; Brad Hoff; John Luginsland

    2010-01-01

    Nonlinear transmission lines have been demonstrated to be an effective technique for generating high power ultrawideband or mesoband radiation without the need for a vacuum system, electron beam, or magnet. Experiments have been performed at UM on a discrete element nonlinear transmission line that uses ferrite inductors as the nonlinear element. Pulse sharpening of multi-kA input pulses has been observed

  19. Input-Based Incremental Vocabulary Instruction

    ERIC Educational Resources Information Center

    Barcroft, Joe

    2012-01-01

    This fascinating presentation of current research undoes numerous myths about how we most effectively learn new words in a second language. In clear, reader-friendly text, the author details the successful approach of IBI vocabulary instruction, which emphasizes the presentation of target vocabulary as input early on and the incremental (gradual)…

  20. Adaptive Random Testing with Combinatorial Input Domain

    PubMed Central

    Lu, Yansheng

    2014-01-01

    Random testing (RT) is a fundamental testing technique to assess software reliability, by simply selecting test cases in a random manner from the whole input domain. As an enhancement of RT, adaptive random testing (ART) has better failure-detection capability and has been widely applied in different scenarios, such as numerical programs, some object-oriented programs, and mobile applications. However, not much work has been done on the effectiveness of ART for the programs with combinatorial input domain (i.e., the set of categorical data). To extend the ideas to the testing for combinatorial input domain, we have adopted different similarity measures that are widely used for categorical data in data mining and have proposed two similarity measures based on interaction coverage. Then, we propose a new version named ART-CID as an extension of ART in combinatorial input domain, which selects an element from categorical data as the next test case such that it has the lowest similarity against already generated test cases. Experimental results show that ART-CID generally performs better than RT, with respect to different evaluation metrics. PMID:24772036

  1. Muscle Tremor as an Input Mechanism

    Microsoft Academic Search

    Steven Strachan; Hamilton Institute

    2004-01-01

    We present the use of human physiological tremor, detected by a linear accelerometer, as a novel form of input for mo- bile devices. This allows the device to be aware if it is being held in a human hand, and in which posture. It also has se- curity applications, as human tremor characteristics are indi- vidual. We describe two simple

  2. "Thumball" Auxiliary Data-Input Device

    NASA Technical Reports Server (NTRS)

    Garner, H. Douglas; Busquets, Anthony M.; Hogge, Thomas W.; Parrish, Russell V.

    1988-01-01

    Track-ball-type device mounted on joystick and operated by thumb. Thumball designed to enable precise input of data about two different axes to autopilot, avionics computer, or other electronic device without need for operator to remove hands from joystick or other vehicle control levers.

  3. SWAT 2012 Input/Output Documentation

    E-print Network

    Arnold, J.G.; Kiniry, J.R.; Srinivasan, R.; Williams, J.R.; Haney, E.B.; Neitsch, S.L.

    2013-03-04

    The Soil and Water Assessment Tool (SWAT) is a comprehensive model that requires a diversity of information in order to run. Novice users may feel overwhelmed by the variety and number of inputs when they first begin to use the model. This document...

  4. Tactical voice input\\/output devices

    Microsoft Academic Search

    D. Ruppe; B. Tirabassi

    1992-01-01

    The authors address the technology insertion and feasibility demonstration issues that are paramount to the effective implementation of voice interaction between man and machine. Results of preliminary feasibility demonstrations are discussed in three critical technology areas: (1) input and output appliances that offer noise immunity, (2) voice recognition and speech synthesis accuracy, and (3) command and control vocabulary development and

  5. Treatments of Precipitation Inputs to Hydrologic Models

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Hydrological models are used to assess many water resources problems from agricultural use and water quality to engineering issues. The success of these models are dependent on correct parameterization; the most sensitive being the rainfall input time series. These records can come from land-based ...

  6. Using Input Buffers for Streaming XSLT Processing

    Microsoft Academic Search

    Jana Dvoráková; Filip Zavoral

    2009-01-01

    We present a buffering streaming engine for processing top-down XSLT transformations. It consists of an analyzer and a transformer. The analyzer examines given top-down XSLT and XSD, and gen- erates fragments which identify parts of XSD need to be buffered when XSLT is applied. The fragments are passed to the transformer which processes XSLT on an input XML document conforming

  7. Multiple Input Microcantilever Sensor with Capacitive Readout

    SciTech Connect

    Britton, C.L., Jr.; Brown, G.M.; Bryan, W.L.; Clonts, L.G.; DePriest, J.C.; Emergy, M.S.; Ericson, M.N.; Hu, Z.; Jones, R.L.; Moore, M.R.; Oden, P.I.; Rochelle, J.M.; Smith, S.F.; Threatt, T.D.; Thundat, T.; Turner, G.W.; Warmack, R.J.; Wintenberg, A.L.

    1999-03-11

    A surface-micromachined MEMS process has been used to demonstrate multiple-input chemical sensing using selectively coated cantilever arrays. Combined hydrogen and mercury-vapor detection was achieved with a palm-sized, self-powered module with spread-spectrum telemetry reporting.

  8. Portfolio Selection with Qualitative Input Anant Chiarawongsea

    E-print Network

    Van Roy, Ben

    Portfolio Selection with Qualitative Input Anant Chiarawongsea , Seksan Kiatsupaibulb, , Sunti and Engineering, Stanford University, CA 94305-4023, USA Abstract We formulate a mean-variance portfolio selection the problem. This model and algorithm can be used, for exam- ple, when a portfolio manager determines that one

  9. Optimum Input Leads for Cryogenic Apparatus

    Microsoft Academic Search

    Richard McFee

    1959-01-01

    Electrical leads carrying currents into cryogenic apparatus also introduce heat. Even with an ideal Carnot cycle, the mechanical power needed to remove this heat can be one hundred or more times the heat flow itself. If the currents and hence the input leads are heavy, a very sizeable refrigerator may be required. In this article the configuration of the leads

  10. Consanguine Calculations Input File: blood.in

    E-print Network

    California at Berkeley, University of

    1 of 20 Problem A+ Consanguine Calculations Input File: blood.in Every person's blood has 2 markers in a particular ABO blood type for that person. Combination ABO Blood Type AA A AB AB AO A BB B BO B OO O Likewise, every person has two alleles for the blood Rh factor, represented by the characters + and -. Someone who

  11. Gravity Transform for Input Conditioning in

    E-print Network

    Paiva, António R. C.

    Gravity Transform for Input Conditioning in Brain Machine Interfaces António R. C. Paiva, José C. Motivation 2. Methods i. Gravity Transform ii. Modeling and output sensitivity analysis 3. Data Analysis #12;3 Outline 1. Motivation 2. Methods i. Gravity Transform ii. Modeling and output sensitivity analysis 3. Data

  12. Input and Intake in Language Acquisition

    ERIC Educational Resources Information Center

    Gagliardi, Ann C.

    2012-01-01

    This dissertation presents an approach for a productive way forward in the study of language acquisition, sealing the rift between claims of an innate linguistic hypothesis space and powerful domain general statistical inference. This approach breaks language acquisition into its component parts, distinguishing the input in the environment from…

  13. IMAGES, IMAGES, IMAGES

    SciTech Connect

    Marcus, A.

    1980-07-01

    The role of images of information (charts, diagrams, maps, and symbols) for effective presentation of facts and concepts is expanding dramatically because of advances in computer graphics technology, increasingly hetero-lingual, hetero-cultural world target populations of information providers, the urgent need to convey more efficiently vast amounts of information, the broadening population of (non-expert) computer users, the decrease of available time for reading texts and for decision making, and the general level of literacy. A coalition of visual performance experts, human engineering specialists, computer scientists, and graphic designers/artists is required to resolve human factors aspects of images of information. The need for, nature of, and benefits of interdisciplinary effort are discussed. The results of an interdisciplinary collaboration are demonstrated in a product for visualizing complex information about global energy interdependence. An invited panel will respond to the presentation.

  14. Conversion of arterial input functions for dual pharmacokinetic modeling using Gd-DTPA/MRI and 18F-FDG/PET.

    PubMed

    Poulin, Eric; Lebel, Réjean; Croteau, Etienne; Blanchette, Marie; Tremblay, Luc; Lecomte, Roger; Bentourkia, M'hamed; Lepage, Martin

    2013-03-01

    Reaching the full potential of magnetic resonance imaging (MRI)-positron emission tomography (PET) dual modality systems requires new methodologies in quantitative image analyses. In this study, methods are proposed to convert an arterial input function (AIF) derived from gadolinium-diethylenetriaminepentaacetic acid (Gd-DTPA) in MRI, into a (18)F-fluorodeoxyglucose ((18)F-FDG) AIF in PET, and vice versa. The AIFs from both modalities were obtained from manual blood sampling in a F98-Fisher glioblastoma rat model. They were well fitted by a convolution of a rectangular function with a biexponential clearance function. The parameters of the biexponential AIF model were found statistically different between MRI and PET. Pharmacokinetic MRI parameters such as the volume transfer constant (K(trans)), the extravascular-extracellular volume fraction (?(e)), and the blood volume fraction (?(p)) calculated with the Gd-DTPA AIF and the Gd-DTPA AIF converted from (18)F-FDG AIF normalized with or without blood sample were not statistically different. Similarly, the tumor metabolic rates of glucose (TMRGlc) calculated with (18) F-FDG AIF and with (18) F-FDG AIF obtained from Gd-DTPA AIF were also found not statistically different. In conclusion, only one accurate AIF would be needed for dual MRI-PET pharmacokinetic modeling in small animal models. PMID:22570280

  15. 3D seismic imaging, example of 3D area in the middle of Banat

    NASA Astrophysics Data System (ADS)

    Antic, S.

    2009-04-01

    3D seismic imaging was carried out in the 3D seismic volume situated in the middle of Banat region in Serbia. The 3D area is about 300 km square. The aim of 3D investigation was defining geology structures and techtonics especially in Mesozoik complex. The investigation objects are located in depth from 2000 to 3000 m. There are number of wells in this area but they are not enough deep to help in the interpretation. It was necessary to get better seismic image in deeper area. Acquisition parameters were satisfactory (good quality of input parameters, length of input data was 5 s, fold was up to 4000 %) and preprocessed data was satisfied. GeoDepth is an integrated system for 3D velocity model building and for 3D seismic imaging. Input data for 3D seismic imaging consist of preprocessing data sorted to CMP gathers and RMS stacking velocity functions. Other type of input data are geological information derived from well data, time migrated images and time migrated maps. Workflow for this job was: loading and quality control the input data (CMP gathers and velocity), creating initial RMS Velocity Volume, PSTM, updating the RMS Velocity Volume, PSTM, building the Initial Interval Velocity Model, PSDM, updating the Interval Velocity Model, PSDM. In the first stage the attempt is to derive initial velocity model as simple as possible as.The higher frequency velocity changes are obtained in the updating stage. The next step, after running PSTM, is the time to depth conversion. After the model is built, we generate a 3D interval velocity volume and run 3D pre-stack depth migration. The main method for updating velocities is 3D tomography. The criteria used in velocity model determination are based on the flatness of pre-stack migrated gathers or the quality of the stacked image. The standard processing ended with poststack 3D time migration. Prestack depth migration is one of the powerful tool available to the interpretator to develop an accurate velocity model and get good seismic image. A comparison of a time and depth migrated sections highlights the improvements in imaging quality. On depth migrated section imaging and fault resolution is improved and is easer to get more complex and realistic geological model.

  16. An analysis of the acoustic input impedance of the ear.

    PubMed

    Withnell, Robert H; Gowdy, Lauren E

    2013-10-01

    Ear canal acoustics was examined using a one-dimensional lossy transmission line with a distributed load impedance to model the ear. The acoustic input impedance of the ear was derived from sound pressure measurements in the ear canal of healthy human ears. A nonlinear least squares fit of the model to data generated estimates for ear canal radius, ear canal length, and quantified the resistance that would produce transmission losses. Derivation of ear canal radius has application to quantifying the impedance mismatch at the eardrum between the ear canal and the middle ear. The length of the ear canal was found, in general, to be longer than the length derived from the one-quarter wavelength standing wave frequency, consistent with the middle ear being mass-controlled at the standing wave frequency. Viscothermal losses in the ear canal, in some cases, may exceed that attributable to a smooth rigid wall. Resistance in the middle ear was found to contribute significantly to the total resistance. In effect, this analysis "reverse engineers" physical parameters of the ear from sound pressure measurements in the ear canal. PMID:23917695

  17. A robust algorithm for sky background computation in CCD images

    E-print Network

    F. Patat

    2003-01-27

    In this paper we present a non-interactive algorithm to estimate a representative value for the sky background on CCD images. The method we have devised uses the mode as a robust estimator of the background brightness in sub-windows distributed across the input frame. The presence of contaminating objects is detected through the study of the local intensity distribution function and the perturbed areas are rejected using a statistical criterion which was derived from numerical simulations. The technique has been extensively tested on a large amount of images and it is suitable for fully automatic processing of large data volumes. The implementation we discuss here has been optimized for the ESO-FORS1 instrument, but it can be easily generalized to all CCD imagers with a sufficiently large field of view. The algorithm has been successfully used for the UBVRI ESO-Paranal night sky brightness survey (Patat 2003).

  18. Clouds of Venus. Input to VIRA.

    NASA Astrophysics Data System (ADS)

    Ignatiev, Nikolay; Zasova, Ludmila

    2012-07-01

    Venus is completely covered by a thick clod deck. Its' total optical depth in the visible is equal to 30+/-10. Original VIRA model based on the measurements from Pioneer Venus descent probes and orbiter described mainly cloud particle sizes, properties and their vertical distribution. Later measurements from Venera-15 and Venus Express permitted more detailed studies of horizontal and vertical variations. Imaging of Venus in the UV range shows variety of cloud features that include mottled and streaky clouds in the low latitudes, bright mid-latitude belt and ``polar cap'' with imbedded oval polar dipole. Despite this non-uniform picture the location of the upper boundary of the clouds, derived from the observation of the absorption bands in the reflected IR spectrum, demonstrates a smooth systematic behavior with the latitudinal trends symmetric with respect to equator. In low and middle latitudes the cloud top is located at 72+/-1 km. It decreases poleward of +/-50 degrees and reaches 63--69 km in polar regions. This depression coincides with the eye of the planetary vortex. The effective average particle size radius is equal to (1.3+/-0.5) micron at latitudes of 0--70, with a peak value some 50% larger in the polar regions. Cloud top can experience fast variations of about metricconverterProductID1 km1 km in tens of hours, while larger long-term variations of several kilometers have been observed only at high latitudes. UV markings correlate with the cloud altimetry, however the difference between adjacent UV dark and bright regions never exceeds few hundred meters. Ultraviolet dark spiral arms, which are often seen at about --70 degress, correspond to higher altitudes or to the regions with strong latitudinal gradient of the cloud top altitude. In contrast to the relatively uniform upper cloud boundary, strong variations of the brightness temperature at specific near infrared wavelengths, especially in low latitudes, are related to variations of the cloud thickness in the middle and low cloud decks consistent with significant convective activity at these levels. The morphology of the holes tends from highly variable orientations of features with aspect ratios of nearly one at low latitudes, to very large aspect ratios and zonally oriented features at higher latitudes.

  19. Two full-bridge input-series-output-parallel integrated-magnetic converter for high input voltage

    Microsoft Academic Search

    Xuejun Mal; Jinhong Niu; Yong Kang

    2005-01-01

    In this paper, a new topology for high input voltage converter with input-series-output-parallel is presented. A key problem of this topology is the input voltage balancing. A voltage error between two inputs capacitor is sensed and controlled. An integrated-magnetic transformer is applied to realize the input voltage sharing. Three closed loops of output voltage, limited load current and input capacitor

  20. Recovering 3D Human Pose from Monocular Images

    E-print Network

    Boyer, Edmond

    a learning-based method for recovering 3D human body pose from single images and monocular image sequences a model that directly recovers pose estimates from observable image quantities. In particular, example-based for training image(s) similar to the given input image and interpolating from their poses [5], [18], [22], [26

  1. Transurethral light delivery for prostate photoacoustic imaging

    NASA Astrophysics Data System (ADS)

    Lediju Bell, Muyinatu A.; Guo, Xiaoyu; Song, Danny Y.; Boctor, Emad M.

    2015-03-01

    Photoacoustic imaging has broad clinical potential to enhance prostate cancer detection and treatment, yet it is challenged by the lack of minimally invasive, deeply penetrating light delivery methods that provide sufficient visualization of targets (e.g., tumors, contrast agents, brachytherapy seeds). We constructed a side-firing fiber prototype for transurethral photoacoustic imaging of prostates with a dual-array (linear and curvilinear) transrectal ultrasound probe. A method to calculate the surface area and, thereby, estimate the laser fluence at this fiber tip was derived, validated, applied to various design parameters, and used as an input to three-dimensional Monte Carlo simulations. Brachytherapy seeds implanted in phantom, ex vivo, and in vivo canine prostates at radial distances of 5 to 30 mm from the urethra were imaged with the fiber prototype transmitting 1064 nm wavelength light with 2 to 8 mJ pulse energy. Prebeamformed images were displayed in real time at a rate of 3 to 5 frames per second to guide fiber placement and beamformed offline. A conventional delay-and-sum beamformer provided decreasing seed contrast (23 to 9 dB) with increasing urethra-to-target distance, while the short-lag spatial coherence beamformer provided improved and relatively constant seed contrast (28 to 32 dB) regardless of distance, thus improving multitarget visualization in single and combined curvilinear images acquired with the fiber rotating and the probe fixed. The proposed light delivery and beamforming methods promise to improve key prostate cancer detection and treatment strategies.

  2. Ecosystem Services Derived from Headwater Catchments

    EPA Science Inventory

    We used data from the USEPA?s wadeable streams assessment (WSA), US Forest Service?s forest inventory and analysis (FIA), and select USFS experimental forests (EF) to investigate potential ecosystems services derived from headwater catchments. C, N, and P inputs to these catchmen...

  3. Perception of the immediate extrapersonal space through proprioceptive inputs.

    PubMed

    Hocherman, S; Aharonson, D; Medalion, B; Hocherman, I

    1988-01-01

    In the present work we sought to examine the idea that an internalized representation of space can be formed and used in the absence of visual information. To this end human subjects were trained to locate 5 points within a horizontal plane at shoulder level, under guidance of an acoustic signal. Next, reaching accuracy was determined for both the trained and the untrained hands without external cues. This allowed comparison of hand positioning that could be based upon a memory trace or proprioceptive inputs (trained hand) to hand positioning that must be based upon a more abstract internal representation than proprioceptive memory (untrained hand). The effect of training on reach accuracy of the two hands and the effect of prolongation the time interval between guided and recall (unguided) trials were studied. Finally, subjects were asked to interpolate between already learned target positions, a procedure which tested their ability to utilize an abstract construct of space. The relative contribution of the elbow and shoulder joints to reaching errors was determined. This analysis served to evaluate whether representation of spatial locations was based on joint angle coordinates, or on a more abstract extracorporeal reference system. Our results indicate that a memorized sensory image of the limb, which corresponds to the hand being at the target position, is used whenever possible. An abstract representation of position is used whenever comparison of the actual sensory input to a memorized sensory trace is made impossible, costing an approximately 25% reduction in accuracy.(ABSTRACT TRUNCATED AT 250 WORDS) PMID:3215303

  4. Engineering input/output nodes in prokaryotic regulatory circuits.

    PubMed

    de Las Heras, Aitor; Carreño, Carlos A; Martínez-García, Esteban; de Lorenzo, Víctor

    2010-09-01

    A large number of prokaryotic regulatory elements have been interfaced artificially with biological circuits that execute specific expression programs. Engineering such circuits involves the association of input/output components that perform discrete signal-transfer steps in an autonomous fashion while connected to the rest of the network with a defined topology. Each of these nodes includes a signal-recognition component for the detection of the relevant physicochemical or biological stimulus, a molecular device able to translate the signal-sensing event into a defined output and a genetic module capable of understanding such an output as an input for the next component of the circuit. The final outcome of the process can be recorded by means of a reporter product. This review addresses three such aspects of forward engineering of signal-responding genetic parts. We first recap natural and non-natural regulatory assets for designing gene expression in response to predetermined signals - chemical or otherwise. These include transcriptional regulators developed by in vitro evolution (or designed from scratch), and synthetic riboswitches derived from in vitro selection of aptamers. Then we examine recent progress on reporter genes, whose expression allows the quantification and parametrization of signal-responding circuits in their entirety. Finally, we critically examine recent work on other reporters that confer bacteria with gross organoleptic properties (e.g. distinct odour) and the interfacing of signal-sensing devices with determinants of community behaviour. PMID:20618867

  5. Optimum employment of satellite indirect soundings as numerical model input

    NASA Technical Reports Server (NTRS)

    Horn, L. H.; Derber, J. C.; Koehler, T. L.; Schmidt, B. D.

    1981-01-01

    The characteristics of satellite-derived temperature soundings that would significantly affect their use as input for numerical weather prediction models were examined. Independent evaluations of satellite soundings were emphasized to better define error characteristics. Results of a Nimbus-6 sounding study reveal an underestimation of the strength of synoptic scale troughs and ridges, and associated gradients in isobaric height and temperature fields. The most significant errors occurred near the Earth's surface and the tropopause. Soundings from the TIROS-N and NOAA-6 satellites were also evaluated. Results again showed an underestimation of upper level trough amplitudes leading to weaker thermal gradient depictions in satellite-only fields. These errors show a definite correlation to the synoptic flow patterns. In a satellite-only analysis used to initialize a numerical model forecast, it was found that these synoptically correlated errors were retained in the forecast sequence.

  6. Real-time image enhancement

    NASA Technical Reports Server (NTRS)

    Wong, V. S.

    1981-01-01

    Pipelined system with "vision" algorithm is implemented on LSI chip that processes input digital image data to produce image-edge map. System contains 3 input adder, difference and absolute value cells, and adder and comparator. Data store for 1 to 2 ms, and are easily transmitted or isolated; design has reduced package count and number of interconnections for increased reliability. Applications include locating objects on moving belt, deep-sea and coal mining, and control of robotic rovers.

  7. Image Segmentation Based on Height Maps

    Microsoft Academic Search

    Gabriele Peters; Jochen Kerdels

    2007-01-01

    In this paper we introduce a new method for image segmen- tation. It is based on a height map generated from the input image. The height map characterizes the image content in such a way that the application of the watershed concept provides a proper segmentation of the image. The height map enables the watershed method to provide better segmentation

  8. Multimodal interfaces with voice and gesture input

    SciTech Connect

    Milota, A.D.; Blattner, M.M.

    1995-07-20

    The modalities of speech and gesture have different strengths and weaknesses, but combined they create synergy where each modality corrects the weaknesses of the other. We believe that a multimodal system such a one interwining speech and gesture must start from a different foundation than ones which are based solely on pen input. In order to provide a basis for the design of a speech and gesture system, we have examined the research in other disciplines such as anthropology and linguistics. The result of this investigation was a taxonomy that gave us material for the incorporation of gestures whose meanings are largely transparent to the users. This study describes the taxonomy and gives examples of applications to pen input systems.

  9. Application of computer voice input/output

    SciTech Connect

    Ford, W.; Shirk, D.G.

    1981-01-01

    The advent of microprocessors and other large-scale integration (LSI) circuits is making voice input and output for computers and instruments practical; specialized LSI chips for speech processing are appearing on the market. Voice can be used to input data or to issue instrument commands; this allows the operator to engage in other tasks, move about, and to use standard data entry systems. Voice synthesizers can generate audible, easily understood instructions. Using voice characteristics, a control system can verify speaker identity for security purposes. Two simple voice-controlled systems have been designed at Los Alamos for nuclear safeguards applicaations. Each can easily be expanded as time allows. The first system is for instrument control that accepts voice commands and issues audible operator prompts. The second system is for access control. The speaker's voice is used to verify his identity and to actuate external devices.

  10. Handling Input on Windows Phone 7

    Microsoft Academic Search

    Rob Cameron

    \\u000a Handling input is a critical aspect of any application, but it is an especially unique challenge on a mobile device. The first\\u000a consideration is that the user is most likely not sitting in a comfortable chair sipping coffee, casually browsing the Internet.\\u000a A mobile application user is most likely on the go, looking to just get a task done or

  11. Solar wind-magnetosphere energy input functions

    Microsoft Academic Search

    L. F. Bargatze; R. L. McPherron; D. N. Baker

    1985-01-01

    A new formula for the solar wind-magnetosphere energy input parameter, P\\/sub i\\/, is sought by applying the constraints imposed by dimensional analysis. Applying these constraints yields a general equation for P\\/sub i\\/ which is equal to rho V³l\\/sub CF\\/²F(M\\/sub A\\/,theta) where, rho V³ is the solar wind kinetic energy density and l\\/sub CF\\/² is the scale size of the magnetosphere's

  12. Sensory synergy as environmental input integration

    PubMed Central

    Alnajjar, Fady; Itkonen, Matti; Berenz, Vincent; Tournier, Maxime; Nagai, Chikara; Shimoda, Shingo

    2015-01-01

    The development of a method to feed proper environmental inputs back to the central nervous system (CNS) remains one of the challenges in achieving natural movement when part of the body is replaced with an artificial device. Muscle synergies are widely accepted as a biologically plausible interpretation of the neural dynamics between the CNS and the muscular system. Yet the sensorineural dynamics of environmental feedback to the CNS has not been investigated in detail. In this study, we address this issue by exploring the concept of sensory synergy. In contrast to muscle synergy, we hypothesize that sensory synergy plays an essential role in integrating the overall environmental inputs to provide low-dimensional information to the CNS. We assume that sensor synergy and muscle synergy communicate using these low-dimensional signals. To examine our hypothesis, we conducted posture control experiments involving lateral disturbance with nine healthy participants. Proprioceptive information represented by the changes on muscle lengths were estimated by using the musculoskeletal model analysis software SIMM. Changes on muscles lengths were then used to compute sensory synergies. The experimental results indicate that the environmental inputs were translated into the two dimensional signals and used to move the upper limb to the desired position immediately after the lateral disturbance. Participants who showed high skill in posture control were found to be likely to have a strong correlation between sensory and muscle signaling as well as high coordination between the utilized sensory synergies. These results suggest the importance of integrating environmental inputs into suitable low-dimensional signals before providing them to the CNS. This mechanism should be essential when designing the prosthesis' sensory system to make the controller simpler. PMID:25628523

  13. A novel approach to the design of unknown input observers

    Microsoft Academic Search

    Yuping Guan; Mehrdad Saif

    1991-01-01

    A novel state estimator design scheme for linear dynamical systems driven by partially unknown inputs is presented. It is assumed that there is no information available about the unknown inputs, and thus no prior assumption is made about the nature of these inputs. A simple approach for designing a reduced-order unknown input observer (UIO) with pole-placement capability is proposed. By

  14. Mood-as-input and depressive rumination.

    PubMed

    Hawksley, Jack; Davey, Graham C L

    2010-02-01

    This article describes a test of mood-as-input theory predictions as applied to a rumination task in a nonclinical population. An experimenter-controlled interview was used to allow participants to reflect on a personal period of depression while in an experimentally-induced mood state (either negative or positive) or while deploying a specific stop rule for the task (either an "as many as can" or "feel like continuing" stop rule). As predicted by mood-as-input theory, persistence at the rumination task was greatest in the group experiencing negative mood while deploying an "as many as can" stop rule, and this suggests a mechanism that may contribute to perseverative depressive rumination. It is argued that the variables that contributed to perseveration in this study are already known to be characteristic of ruminative thinkers (e.g. negative mood and positive metacognitive beliefs about rumination that will command the deployment of "as many as can" stop rules for rumination). It is also argued that mood-as-input processes may provide a common mechanism for perseverative rumination and perseverative worry, and this common mechanism may account for many of the similarities between these two functionally-distinct activities. PMID:19878928

  15. Input/output modeling for process control

    SciTech Connect

    Holcomb, T.R.; Rhodes, C.A.; Morari, M. [California Institute of Technology, Pasadena, CA (United States)

    1994-12-31

    Traditionally, for ease of operation and analysis, technological systems (manufacturing systems, communication systems, etc.) have been designed to behave in as linear a manner as possible. Increasingly tight specifications, environmental considerations and economic pressures are pushing the operational windows into regions where assumptions of linearity tend to break down. Despite a flurry of activity in the area of nonlinear dynamical systems (both analysis and control systems design) we see very few applications of these new results. One important reason is the lack of suitable nonlinear dynamic models. The objective of this project is the development of tools for building nonlinear models based on input/output data. The developed techniques build on results from nonlinear time series analysis, classical statistics and chemometrics. We show how to use the False Nearest Neighbor method to determine the order of a nonlinear ARMAX model, and explore the local linear structure of the input/output map via PLS (Partial Least Squares or Projection to Local Structures). By putting PLS in the general context of {open_quotes}significance regression{close_quotes} we are able to deal effectively with collinear data sets involving errors on the inputs ({open_quotes}Measurement Error Model{close_quotes}) and outliers ({open_quotes}Robust Regression{close_quotes}).

  16. Common Data Input/Retrieval System

    SciTech Connect

    Pate, J.E.; Muntz, J.E.

    1984-04-01

    The Common Data Input/Retrieval System (CDIRS) is a generalized software system developed at Sandia National Laboratories which is incorporated into an application system to perform application data input and/or retrieval processing. The system operates in the on-line mode in the Transaction-Processing (TIP) environment, and in batch mode. The system may be used for retrieval and/or updating of both the transaction database and the application database. Features provided include data input/retrieval screens which are tailored to designer's specifications, access to transactions via six retrieval paths, backup and recoverability of transactions, and periodic archival of processed transactions. The system consists of 40 programs, of which 36 are written in Cobol and 4 are written in Assembler. Forty-three action codes are provided to accomplish various combinations of DMS activities. Security is available at three levels: datasystem-level, user-level, and transaction-level. The purpose of this paper is to provide an overview of the CDIRS environment from a user perspective. For this reason, some generalizations will be made, and some detail will be omitted. The system is complex, however; it will be necessary to provide enough detail to define the various entities, and attempt to explain how they interface.

  17. A Novel Method for Sidescan Sonar Image Segmentation

    Microsoft Academic Search

    Turgay Celik; Tardi Tjahjadi

    2011-01-01

    In this paper, we propose a novel unsupervised algo- rithm for segmenting sidescan sonar images of seafloor. The pro- posed algorithm does not make any a priori assumption on the na- ture of the input sidescan sonar image. The algorithm first con- structs a multiresolution representation of the input image using the forward and inverse undecimated discrete wavelet transform (UDWT).

  18. Variation in freshwater input to the Eastern US coastal ecosystem

    NASA Astrophysics Data System (ADS)

    Feng, D.; Yoon, Y.; Beighley, E., II; Hughes, R.; Kimbro, D.

    2014-12-01

    Phragmites is one of the most invasive plants in North American wetlands. Although its spread in coastal marshes has been linked by independent studies to urbanization, eutrophication, and salinity change, there is good evidence that these factors may interactively determine invasion success and in turn, the ecosystem services provided by marshes. We hypothesize that the invasion of Phragmites is linked to changes in freshwater inputs due to climate and/or land use change. El Nino/Southern Oscillation (ENSO), originating in the sea surface temperature anomalies (warm or cold) in the eastern tropical Pacific Ocean, is a notable and prominent signal in inter-annual climatic variation. Recent studies shows that the probability of strong El Nino events may increase in the future. In this study, we will investigate the teleconnections between freshwater inputs to the coastal zone along the eastern U.S. and ENSO indices, and attempt to explore the predictability of temporal and spatial variation of freshwater inputs based on ENSO conditions. To quantify changes in freshwater input in this region, hydrologic modeling, remote sensing and field measurements are combined. The Hillslope River Routing (HRR) model is used to simulate hourly streamflow from all watersheds from southern Florida to northern Maine draining into the Atlantic Ocean. The modeling effort utilizes satellite precipitation (Tropical Rainfall Measuring Mission Product 3B42v7: 2001-current with a 3-hr temporal resolution and 0.25 degree spatial resolution), land surface temperature and vegetation measures (Moderate Resolution Imaging Spectroradiometer, MODIS, products: 2001-current with a monthly temporal resolution and 0.05 degree spatial resolution). To account for land cover change, annual MODIS land cover data and time varying population statics are merged to estimate annual land cover characteristics for each sub-catchment within the study region. Static datasets for soils and ground elevations are used. Daily U.S. Geological Survey streamflow data from major river outlets along the coastline are used for model validation. Annual streamflow is characterized in terms of volume of export to the ocean: as total flow, storm flow and baseflow and used to explore longitudinal discharge patterns along the coastline.

  19. Investigation of dynamic SPECT measurements of the arterial input function in human subjects using simulation, phantom and human studies

    NASA Astrophysics Data System (ADS)

    Winant, Celeste D.; Aparici, Carina Mari; Zelnik, Yuval R.; Reutter, Bryan W.; Sitek, Arkadiusz; Bacharach, Stephen L.; Gullberg, Grant T.

    2012-01-01

    Computer simulations, a phantom study and a human study were performed to determine whether a slowly rotating single-photon computed emission tomography (SPECT) system could provide accurate arterial input functions for quantification of myocardial perfusion imaging using kinetic models. The errors induced by data inconsistency associated with imaging with slow camera rotation during tracer injection were evaluated with an approach called SPECT/P (dynamic SPECT from positron emission tomography (PET)) and SPECT/D (dynamic SPECT from database of SPECT phantom projections). SPECT/P simulated SPECT-like dynamic projections using reprojections of reconstructed dynamic 94Tc-methoxyisobutylisonitrile (94Tc-MIBI) PET images acquired in three human subjects (1 min infusion). This approach was used to evaluate the accuracy of estimating myocardial wash-in rate parameters K1 for rotation speeds providing 180° of projection data every 27 or 54 s. Blood input and myocardium tissue time-activity curves (TACs) were estimated using spatiotemporal splines. These were fit to a one-compartment perfusion model to obtain wash-in rate parameters K1. For the second method (SPECT/D), an anthropomorphic cardiac torso phantom was used to create real SPECT dynamic projection data of a tracer distribution derived from 94Tc-MIBI PET scans in the blood pool, myocardium, liver and background. This method introduced attenuation, collimation and scatter into the modeling of dynamic SPECT projections. Both approaches were used to evaluate the accuracy of estimating myocardial wash-in parameters for rotation speeds providing 180° of projection data every 27 and 54 s. Dynamic cardiac SPECT was also performed in a human subject at rest using a hybrid SPECT/CT scanner. Dynamic measurements of 99mTc-tetrofosmin in the myocardium were obtained using an infusion time of 2 min. Blood input, myocardium tissue and liver TACs were estimated using the same spatiotemporal splines. The spatiotemporal maximum-likelihood expectation-maximization (4D ML-EM) reconstructions gave more accurate reconstructions than did standard frame-by-frame static 3D ML-EM reconstructions. The SPECT/P results showed that 4D ML-EM reconstruction gave higher and more accurate estimates of K1 than did 3D ML-EM, yielding anywhere from a 44% underestimation to 24% overestimation for the three patients. The SPECT/D results showed that 4D ML-EM reconstruction gave an overestimation of 28% and 3D ML-EM gave an underestimation of 1% for K1. For the patient study the 4D ML-EM reconstruction provided continuous images as a function of time of the concentration in both ventricular cavities and myocardium during the 2 min infusion. It is demonstrated that a 2 min infusion with a two-headed SPECT system rotating 180° every 54 s can produce measurements of blood pool and myocardial TACs, though the SPECT simulation studies showed that one must sample at least every 30 s to capture a 1 min infusion input function.

  20. Liquid-Crystal-Television Image Subtracters

    NASA Technical Reports Server (NTRS)

    Chao, Tien-Hsin; Liu, Hua-Kuang

    1988-01-01

    Two image-subtraction systems from output images that show differences between input images of two objects. First: differences appear as bright regions in otherwise dark output image. Second: differences and similarities shown by colors. All parts of two images processed simultaneously by optical components only; digital electronic processing of data not required. Concept offers potential for rapid, inexpensive comparison of images in such applications as automatic inspection, medical diagnosis, and robotic vision.

  1. Control Strategy for Input-Series Output-Paralleled Converter

    Microsoft Academic Search

    Xinbo Ruan; Lulu Cheng; Tao Zhang

    2006-01-01

    The input-series output-paralleled (ISOP) converter, which consists of multiple dc-dc modules connected in series at the input and paralleled at the output, are very attractive in the high input voltage and high power applications. The input voltage sharing and output current sharing of the modules of the ISOP converter should be ensured. This paper reveals the relationship between the input

  2. Input impedance of a powerful single-core ferromagnetic inductively coupled plasma source

    SciTech Connect

    Bliokh, Y. P.; Brodsky, Yu. L.; Chashka, Kh. B.; Felsteiner, J.; Slutsker, Ya. Z. [Department of Physics, Technion-Israel Institute of Technology, 32000 Haifa (Israel)

    2010-01-15

    An experimental study of the recently developed version of the ferromagnetic inductively coupled plasma source has shown that under certain circumstances its input impedance becomes almost independent of the delivered rf driving power and (therefore) of the produced plasma density. This plasma source consists of a large ferromagnetic core, which is fully immersed in plasma. This core is surrounded by a primary winding and plasma appears due to gas discharge driven by an rf voltage applied to this primary winding. We have found values of parameters which determine the input impedance in such an ''independent'' regime and derived a quantitative theory which is in good agreement with the measured impedance values.

  3. The Effects of Pre Modified Input, Interactionally Modified Input, and Modified Output on EFL Learners' Comprehension of New Vocabularies

    ERIC Educational Resources Information Center

    Maleki, Zinat; Pazhakh, AbdolReza

    2012-01-01

    The present study was an attempt to investigate the effects of premodified input, interactionally modified input and modified output on 80 EFL learners' comprehension of new words. The subjects were randomly assigned into four groups of pre modified input, interactionally modified input, modified output and unmodified (control) groups. Each group…

  4. Evaluation of the input current quality by three different modulation strategies for SVM controlled matrix converters with input voltage unbalance

    Microsoft Academic Search

    Peter Nielsen; Domenico Casadei; Giovanni Serra; Angelo Tani

    1996-01-01

    A new input current modulation strategy for a matrix power converter is presented. The performance of the new strategy during input voltage unbalance is compared to two other strategies. The difference of the three modulations only concerns the detection of the reference angle for the input current vector. The input current quality is evaluated using four different criteria. It is

  5. In vitro Cellular Uptake and Dimerization of Signal Transducer and Activator of Transcription-3 (STAT3) Identify the Photosensitizing and Imaging-Potential of Isomeric Photosensitizers Derived from Chlorophyll-a and Bacteriochlorophyll-a

    PubMed Central

    Srivatsan, Avinash; Wang, Yanfang; Joshi, Penny; Sajjad, Munawwar; Chen, Yihui; Liu, Chao; Thankppan, Krishnakumar; Missert, Joseph R.; Tracy, Erin; Morgan, Janet; Rigual, Nestor; Baumann, Heinz; Pandey, Ravindra K.

    2011-01-01

    Among the photosensitizers investigated, both ring-D and ring-B reduced chlorins containing the m-iodobenzyloxyethyl group at position-3 and a carboxylic acid functionality at position-172 showed highest uptake by tumor cells and light-dependent photo reaction that correlated with maximal tumor-imaging [positron emission tomography (PET) and fluorescence] and long-term photodynamic therapy (PDT) efficacy in BALB/c mice bearing Colon26 tumors. However, among the ring-D reduced compounds, the isomer containing 1?-m-iobenzyloxyethyl group at position-3 was more effective than the corresponding 8-(1?-m-iodobenzyloxyethyl) derivative. All photosensitizers showed maximum uptake by tumor tissue 24h after injection and the tumors exposed with light at low fluence and fluence rates (128 J/cm2, 14 mW/cm2) produced significantly enhanced tumor eradication than those exposed at higher fluence and fluence rate (135 J/cm,2 75mW/cm2). Interestingly, dose-dependent cellular uptake of the compounds and light-dependent STAT3 dimerization have emerged as sensitive rapid indicators for PDT efficacy in vitro and in vivo and could be used as in vitro/in vivo biomarkers for evaluating and optimizing the in vivo treatment parameters of the existing and new PDT candidates. PMID:21842893

  6. Space vector modulated three-phase to three-phase matrix converter with input power factor correction

    Microsoft Academic Search

    L. Huber; D. Borojevic

    1995-01-01

    Analysis, design, and implementation of the space vector modulated three-phase to three-phase matrix converter with input power factor correction are presented. The majority of published research results on the matrix converter control are given an overview, and the one which employs simultaneous output-voltage and input-current space vector modulation, is systematically reviewed. The modulation algorithm is theoretically derived from the desired

  7. Hospital Quality, Efficiency, and Input Slack Differentials

    PubMed Central

    Valdmanis, Vivian G; Rosko, Michael D; Mutter, Ryan L

    2008-01-01

    Objective To use an advance in data envelopment analysis (DEA) called congestion analysis to assess the trade-offs between quality and efficiency in U.S. hospitals. Study Setting Urban U.S. hospitals in 34 states operating in 2004. Study Design and Data Collection Input and output data from 1,377 urban hospitals were taken from the American Hospital Association Annual Survey and the Medicare Cost Reports. Nurse-sensitive measures of quality came from the application of the Patient Safety Indicator (PSI) module of the Agency for Healthcare Research and Quality (AHRQ) Quality Indicator software to State Inpatient Databases (SID) provided by the Healthcare Cost and Utilization Project (HCUP). Data Analysis In the first step of the study, hospitals’ relative output-based efficiency was determined in order to obtain a measure of congestion (i.e., the productivity loss due to the occurrence of patient safety events). The outputs were adjusted to account for this productivity loss, and a second DEA was performed to obtain input slack values. Differences in slack values between unadjusted and adjusted outputs were used to measure either relative inefficiency or a need for quality improvement. Principal Findings Overall, the hospitals in our sample could increase the total amount of outputs produced by an average of 26 percent by eliminating inefficiency. About 3 percent of this inefficiency can be attributed to congestion. Analysis of subsamples showed that teaching hospitals experienced no congestion loss. We found that quality of care could be improved by increasing the number of labor inputs in low-quality hospitals, whereas high-quality hospitals tended to have slack on personnel. Conclusions Results suggest that reallocation of resources could increase the relative quality among hospitals in our sample. Further, higher quality in some dimensions of care need not be achieved as a result of higher costs or through reduced access to health care. PMID:18783457

  8. Cross-domain object recognition via input-output kernel analysis.

    PubMed

    Guo, Zhenyu; Wang, Z Jane

    2013-08-01

    It is of great importance to investigate the domain adaptation problem of image object recognition, because now image data is available from a variety of source domains. To understand the changes in data distributions across domains, we study both the input and output kernel spaces for cross-domain learning situations, where most labeled training images are from a source domain and testing images are from a different target domain. To address the feature distribution change issue in the reproducing kernel Hilbert space induced by vector-valued functions, we propose a domain adaptive input-output kernel learning (DA-IOKL) algorithm, which simultaneously learns both the input and output kernels with a discriminative vector-valued decision function by reducing the data mismatch and minimizing the structural error. We also extend the proposed method to the cases of having multiple source domains. We examine two cross-domain object recognition benchmark data sets, and the proposed method consistently outperforms the state-of-the-art domain adaptation and multiple kernel learning methods. PMID:23743772

  9. 6-Bromocholesterol derivatives

    SciTech Connect

    Flanagan, R.J.

    1984-02-07

    Novel 6-bromo derivatives of cholesterol have the formula 3-(R-O-),6-BR,17-((H3C-)2-HC-H2C-H2C-H2C-HC(-CH3)-)-ESTR-5-ENE Such compounds are prepared from the known 6-iodocholesterol by treatment with cuprous bromide. These compounds, labelled with radioisotopes of Br-82 or Br-77, are localized in the adrenal, mammary and ovary tissue of female mammals and in the adrenal or prostate tissue of males when administered to such individuals. This provides a method for imaging adrenal, ovary or prostate tissue which is superior to use of the prior art 6-iodo-cholesterol.

  10. Spatial gamut mapping for preserving the details of an image

    NASA Astrophysics Data System (ADS)

    Song, In-Yong; Ha, Ho-Gun; Kyung, Wang-Jun; Ha, Yeong-Ho

    2012-01-01

    The spatial gamut-mapping algorithm (SGMA) overcomes the drawbacks of the widely used color-by-color methods. Spatial gamut mapping can preserve detailed information in original images by performing adaptive gamut mapping in surrounding pixels within the image. However, spatial gamut mapping can result in hue shift and the halo effect. In addition, it only preserves the boundary information outside the color gamut; the resulting gamut-mapped image does not sufficiently preserve the detailed information in the input image. In this paper, we propose an SGMA that utilizes details of the input image. Our approach improves detail that is not effectively represented with conventional spatial gamut mapping. This is done by taking an original image and first implementing gamut mapping of the input image. Then, the details of the input image and gamut-mapped image are extracted. By examining the out-of-gamut region, the details of the input image can be preserved when these values are added to the gamut-mapped image. The resulting image is obtained by clipping out-of-gamut pixels, since these pixels are generated in the process of preserving details. We demonstrated that images obtained using the proposed method are more similar to the input images, compared to images obtained using conventional methods.

  11. Assessment of terrigenous organic carbon input to the total organic carbon in sediments from Scottish transitional waters Hydrology and Earth System Sciences, 6(6), 959970 (2002) EGS

    E-print Network

    Paris-Sud XI, Université de

    2002-01-01

    Assessment of terrigenous organic carbon input to the total organic carbon in sediments from of terrigenous organic carbon input to the total organic carbon in sediments from Scottish transitional waters This paper addresses the assessment of terrestrially derived organic carbon in sediments from two Scottish

  12. Ground motion input in seismic evaluation studies

    SciTech Connect

    Sewell, R.T.; Wu, S.C.

    1996-07-01

    This report documents research pertaining to conservatism and variability in seismic risk estimates. Specifically, it examines whether or not artificial motions produce unrealistic evaluation demands, i.e., demands significantly inconsistent with those expected from real earthquake motions. To study these issues, two types of artificial motions are considered: (a) motions with smooth response spectra, and (b) motions with realistic variations in spectral amplitude across vibration frequency. For both types of artificial motion, time histories are generated to match target spectral shapes. For comparison, empirical motions representative of those that might result from strong earthquakes in the Eastern U.S. are also considered. The study findings suggest that artificial motions resulting from typical simulation approaches (aimed at matching a given target spectrum) are generally adequate and appropriate in representing the peak-response demands that may be induced in linear structures and equipment responding to real earthquake motions. Also, given similar input Fourier energies at high-frequencies, levels of input Fourier energy at low frequencies observed for artificial motions are substantially similar to those levels noted in real earthquake motions. In addition, the study reveals specific problems resulting from the application of Western U.S. type motions for seismic evaluation of Eastern U.S. nuclear power plants.

  13. Inferring electric fields and currents from ground magnetometer data - A test with theoretically derived inputs

    NASA Technical Reports Server (NTRS)

    Wolf, R. A.; Kamide, Y.

    1983-01-01

    Advanced techniques considered by Kamide et al. (1981) seem to have the potential for providing observation-based high time resolution pictures of the global ionospheric current and electric field patterns for interesting events. However, a reliance on the proposed magnetogram-inversion schemes for the deduction of global ionospheric current and electric field patterns requires proof that reliable results are obtained. 'Theoretical' tests of the accuracy of the magnetogram inversion schemes have, therefore, been considered. The present investigation is concerned with a test, involving the developed KRM algorithm and the Rice Convection Model (RCM). The test was successful in the sense that there was overall agreement between electric fields and currents calculated by the RCM and KRM schemes.

  14. Deriving a simulation input generator and a coverage metric from a formal specification

    Microsoft Academic Search

    Kanna Shimizu; David L. Dill

    2002-01-01

    This paper presents novel uses of functional interface specifications for verifying RTL designs. We demonstrate how a simulation environment, a correctness checker, and a functional coverage metric are all created automatically from a single specification. Additionally, the process exploits the structure of a specification written with simple style rules. The methodology was used to verify a large-scale I\\/O design from

  15. Laser speckle suppression by the phase modulation of input beam in a multimode fiber

    NASA Astrophysics Data System (ADS)

    Yang, Cong; Han, Jian; Wu, Yuanjie; Ye, Huiqi; Xiao, Dong

    2014-07-01

    When a multimode fiber transmits a laser beam, the speckle will form in its output field. A dynamic fiber scrambler could be used to suppress the speckle. No matter what actual way of suppressing speckle is, such as fiber scrambling or using a rotating phase plate, the suppression is the result of exerting disturbance in the process of the speckle forming. We could disturb the phase of the input beam with specific method to weaken the speckle effect. To get a speckle image formed by a multimode fiber, we simulate different diffraction patterns under different phase conditions using diffraction model, in which the phase of the input beam is modulated by a rough surface, and then sum them to form the instantaneous speckle. To study the speckle suppression, we superpose instantaneous speckles, and as a consequence the final speckle is suppressed. The simulation would help us understand the speckle suppression experiment with the input beam phase modulation conducted in our lab.

  16. Object Oriented Program Derivation This chapter examines how implementations can be derived from the formal object oriented LOTOS

    E-print Network

    Gibson, J. Paul

    Chapter 6 Object Oriented Program Derivation This chapter examines how implementations can be derived from the formal object oriented LOTOS designs which arise from application of the methods de ned in chapters 2 through to 5. 6.1: High-level Object Oriented Design as Input to Implementation This section

  17. Exploring Spatial Overlap of High-Uptake Regions Derived From Dual Tracer Positron Emission Tomography-Computer Tomography Imaging Using 18F-Fluorodeoxyglucose and 18F-Fluorodeoxythymidine in Nonsmall Cell Lung Cancer Patients: A Prospective Pilot Study.

    PubMed

    Liu, Jing; Li, Chengqiang; Hu, Man; Lu, Jie; Shi, Xiaorong; Xing, Ligang; Sun, Xindong; Fu, Zheng; Yu, Jinming; Meng, Xue

    2015-05-01

    Interest is growing in radiotherapy to nonuniformly boost radioresistant regions within nonsmall cell lung cancer (NSCLC) using molecular imaging techniques. The complexity of tumor behavior is beyond the ability of any single radiotracer to reveal. We hold dual tracer positron emission tomography-computer tomography (PET/CT) imaging with fluorodeoxyglucose (FDG) and fluorodeoxythymidine (FLT) for NSCLC patients to offer an integrated overlook of tumor biological behaviors quantitatively and localizationally, which may help biological target volume delineation and subvolume boost.Pathological confirmed that NSCLC patients were eligible. FDG and FLT PET/CT were performed for each patient before anticancer treatment and coregistrated for analysis. Maximum and mean standardized uptake values (SUVmax and SUVmean) were calculated automatically. Metabolic volumes (MVs) were delineated by a fixed 50% of SUVmax in FDG PET/CT and proliferative volumes (PVs) were delineated by 50% to 90% of SUVmax with 10% interval in FLT PET/CT. Overlap ratio (OR) were determined as overlapped volume between MV and PV divided PV. Conventional contrast-enhanced CT-based intensity-modulated radiotherapy (IMRT) plans with and without additional PET/CT-guided subtarget boost were made for each of the 5 typical NSCLC patients. Dosimetric parameters derived from dose-volume histogram, tumor control probability (TCP), and normal tissue complication probability (NTCP) of lung, esophagus, heart, and spinal cord were calculated and compared.Thirty-one patients were prospectively included and 23 were selected for analysis. Totally, 23 primary diseases, 41 metastatic lymph nodes, and 15 metastatic lesions were positive in dual PET/CTs and included for analysis. Median ORs increased from 58.61% to 93.12% under thresholds of 50% of SUVmax in FDG PET/CT and increased thresholds from 50% to 90% of SUVmax in FLT PET/CT. Based on conventional IMRT, additional boost to union of high FDG (determined by 50% SUVmax) and FLT (determined by 80% SUVmax) uptake subtargets exhibited higher TCP without significant elevated NTCP of lung, esophagus, spinal cord, and heart.Dual tracer PET/CT of FDG and FLT is suggested for NSCLC patients to guide tumor target delineation in clinical practice. FDG PET/CT is necessary whereas FLT PET/CT may be optional when guiding tumor target delineation clinically. Additional information from randomized trials is required to validate. PMID:25929896

  18. Use of Ferritin Expression, Regulated by Neural Cell-Specific Promoters in Human Adipose Tissue-Derived Mesenchymal Stem Cells, to Monitor Differentiation with Magnetic Resonance Imaging In Vitro

    PubMed Central

    Mo, Cuiping; Mu, Shuhua; Jiang, Xiaogang; Li, Xiaoyun; Zhong, Shizhen; Zhao, Zhenfu; Zhou, Guangqian

    2015-01-01

    The purpose of this study was to establish a method for monitoring the neural differentiation of stem cells using ferritin transgene expression, under the control of a neural-differentiation-inducible promoter, and magnetic resonance imaging (MRI). Human adipose tissue-derived mesenchymal stem cells (hADMSCs) were transduced with a lentivirus containing the human ferritin heavy chain 1 (FTH1) gene coupled to one of three neural cell-specific promoters: human synapsin 1 promoter (SYN1p, for neurons), human glial fibrillary acidic protein promoter (GFAPp, for astrocytes), and human myelin basic protein promoter (MBPp, for oligodendrocytes). Three groups of neural-differentiation-inducible ferritin-expressing (NDIFE) hADMSCs were established: SYN1p-FTH1, GFAPp-FTH1, and MBPp-FTH1. The proliferation rate of the NDIFE hADMSCs was evaluated using a Cell Counting Kit-8 assay. Ferritin expression was assessed with western blotting and immunofluorescent staining before and after the induction of differentiation in NDIFE hADMSCs. The intracellular iron content was measured with Prussian blue iron staining and inductively coupled plasma mass spectrometry. R2 relaxation rates were measured with MRI in vitro. The proliferation rates of control and NDIFE hADMSCs did not differ significantly (P > 0.05). SYN1p-FTH1, GFAPp-FTH1, and MBPp-FTH1 hADMSCs expressed specific markers of neurons, astrocytes, and oligodendrocytes, respectively, after neural differentiation. Neural differentiation increased ferritin expression twofold, the intracellular iron content threefold, and the R2 relaxation rate two- to threefold in NDIFE hADMSCs, resulting in notable hypointensity in T2-weighted images (P < 0.05). These results were cross-validated. Thus, a link between neural differentiation and MRI signals (R2 relaxation rate) was established in hADMSCs. The use of MRI and neural-differentiation-inducible ferritin expression is a viable method for monitoring the neural differentiation of hADMSCs. PMID:26176961

  19. Iterative image fusion technique using fuzzy and neuro fuzzy logic and applications

    Microsoft Academic Search

    Rahul Ranjan; H. Singh; T. Meitzler; G. R. Gerhart

    2005-01-01

    Image fusion has attracted a widespread attention owing to applications in medical imaging, automotive and remote sensing. Image fusion deals with integrating data obtained from different sources of information for intelligent systems. Image fusion provides output as a single image from a set of input images obtained from different sources or techniques. Different approaches in image fusion provide different type

  20. I2T: Image Parsing to Text Description

    Microsoft Academic Search

    Benjamin Z. Yao; Xiong Yang; Liang Lin; Mun Wai Lee; Song-Chun Zhu

    2010-01-01

    In this paper, we present an image parsing to text description (I2T) framework that generates text descriptions of image and video content based on image understanding. The proposed I2T framework follows three steps: 1) input images (or video frames) are decomposed into their constituent visual patterns by an image parsing engine, in a spirit similar to parsing sentences in natural

  1. Fractal Image Compression on a Pseudo Spiral Architecture

    Microsoft Academic Search

    Huaqing Wang; Meiqing Wang; Tom Hintz; Xiangjian He; Qiang Wu

    2005-01-01

    Fractal image compression is a relatively recent image compression method which exploits similarities in different parts of the image. The basic idea is to represent an image by fractals and each of which is the fixed point of an Iterated Function System (IFS). Therefore, an input image can be represented by a series of IFS codes rather than pixels. In

  2. Thermal neutron image intensifier tube provides brightly visible radiographic pattern

    NASA Technical Reports Server (NTRS)

    Berger, H.; Kraska, I.; Niklas, W.; Schmidt, A.

    1967-01-01

    Vacuum-type neutron image intensifier tube improves image detection in thermal neutron radiographic inspection. This system converts images to an electron image, and with electron acceleration and demagnification between the input target and output screen, produces a bright image viewed through a closed circuit television system.

  3. Multidimensional Scaling for Matching Low-resolution Face Images

    E-print Network

    Bowyer, Kevin W.

    1 Multidimensional Scaling for Matching Low-resolution Face Images Soma Biswas, Member, IEEE, Kevin performance degrades considerably when the input images are of low resolution as is often the case for images for matching low resolution probe images with higher resolution gallery images, which are often available

  4. SU-E-J-19: Accuracy of Dual-Energy CT-Derived Relative Electron Density for Proton Therapy Dose Calculation

    SciTech Connect

    Mullins, J; Duan, X; Kruse, J; Herman, M [Mayo Clinic, Rochester, MN (United States); Bues, M [Mayo Clinic Arizona, Phoenix, AZ (United States)

    2014-06-01

    Purpose: To determine the suitability of dual-energy CT (DECT) to calculate relative electron density (RED) of tissues for accurate proton therapy dose calculation. Methods: DECT images of RED tissue surrogates were acquired at 80 and 140 kVp. Samples (RED=0.19?2.41) were imaged in a water-equivalent phantom in a variety of configurations. REDs were calculated using the DECT numbers and inputs of the high and low energy spectral weightings. DECT-derived RED was compared between geometric configurations and for variations in the spectral inputs to assess the sensitivity of RED accuracy versus expected values. Results: RED accuracy was dependent on accurate spectral input influenced by phantom thickness and radius from the phantom center. Material samples located at the center of the phantom generally showed the best agreement to reference RED values, but only when attenuation of the surrounding phantom thickness was accounted for in the calculation spectra. Calculated RED changed by up to 10% for some materials when the sample was located at an 11 cm radius from the phantom center. Calculated REDs under the best conditions still differed from reference values by up to 5% in bone and 14% in lung. Conclusion: DECT has previously been used to differentiate tissue types based on RED and Z for binary tissue-type segmentation. To improve upon the current standard of empirical conversion of CT number to RED for treatment planning dose calculation, DECT methods must be able to calculate RED to better than 3% accuracy throughout the image. The DECT method is sensitive to the accuracy of spectral inputs used for calculation, as well as to spatial position in the anatomy. Effort to address adjustments to the spectral calculation inputs based on position and phantom attenuation will be required before DECT-determined RED can achieve a consistent level of accuracy for application in dose calculation.

  5. INGEN: A COBRA-NC input generator user's manual

    SciTech Connect

    Wheeler, C.L.; Dodge, R.E.

    1986-12-01

    The INGEN (INput GENerator) computer program has been developed as a preprocessor to simplify input generation for the COBRA-NC computer program. INGEN uses several empirical correlations and geometric assumptions to simplify the data input requirements for the COBRA-NC computer code. The simplified input scheme is obtained at the expense of much flexibility provided by COBRA-NC. For more complex problems requiring additional flexibility however, INGEN may be used to provide a skeletal input file to which the more detailed input may be added. This report describes the input requirements for INGEN and describes the algorithms and correlations used to generate the COBRA-NC input. 9 refs., 3 figs., 6 tabs.

  6. Toward an inventory of nitrogen input to the United States

    EPA Science Inventory

    Accurate accounting of nitrogen inputs is increasingly necessary for policy decisions related to aquatic nutrient pollution. Here we synthesize available data to provide the first integrated estimates of the amount and uncertainty of nitrogen inputs to the United States. Abou...

  7. Shaping Inputs to Reduce Vibration: A Vector Diagram Approach

    E-print Network

    Singhose, William

    1990-03-01

    This paper describes a method for limiting vibration in flexible systems by shaping the system inputs. Unlike most previous attempts at input shaping, this method does not require an extensive system model or lengthy ...

  8. Observer-based state estimation and unknown input reconstruction for nonlinear complex dynamical systems

    NASA Astrophysics Data System (ADS)

    Yang, Junqi; Zhu, Fanglai; Yu, Kaijiang; Bu, Xuhui

    2015-03-01

    This paper considers the issues of both state estimation and unknown information reconstruction for a class of uncertain complex dynamical networks subject to unknown inputs. First, a robust adaptive sliding mode observer which can be used to estimate the states of complex networks through available measurement outputs is developed by employing both adaptive technique and sliding mode control approach. Second, a high-gain second-order sliding mode observer is considered to exactly estimate the derivatives of the output vectors in a finite time. Third, by using the estimates of the states and output derivatives, a kind of algebraic unknown input reconstruction method is proposed. Finally, some numerical simulation examples are given to illustrate the effectiveness of the proposed methods.

  9. Use of chaotic and random vibrations to generate high frequency test inputs

    SciTech Connect

    Gregory, D. L.; Paez, T. L.

    1990-01-01

    This paper and a companion paper show the traditional limits on amplitude and frequency that can be generated in a laboratory test on a vibration exciter can be substantially extended. This is accomplished by attaching a device to the shaker that permits controlled metal to metal impacts that generate high frequency, high acceleration environment on a test surface. A companion paper (Reference 1) shows that a sinusoidal or random shaker input can be used to generate a random vibration environment on the test surface. This paper derives the three response components that occur on the test surface due to an impact on the bottom surface and the base driven response from the shaker input. These response components are used to generate impulse response functions and frequency response functions which are used in the companion paper to derive power spectral density functions for the overall response. 9 refs., 8 figs.

  10. Automatic parsing of parental verbal input.

    PubMed

    Sagae, Kenji; MacWhinney, Brian; Lavie, Alon

    2004-02-01

    To evaluate theoretical proposals regarding the course of child language acquisition, researchers often need to rely on the processing of large numbers of syntactically parsed utterances, both from children and from their parents. Because it is so difficult to do this by hand, there are currently no parsed corpora of child language input data. To automate this process, we developed a system that combined the MOR tagger, a rule-based parser, and statistical disambiguation techniques. The resultant system obtained nearly 80% correct parses for the sentences spoken to children. To achieve this level, we had to construct a particular processing sequence that minimizes problems caused by the coverage/ambiguity tradeoff in parser design. These procedures are particularly appropriate for use with the CHILDES database, an international corpus of transcripts. The data and programs are now freely available over the Internet. PMID:15190707

  11. REGRESSION ESTIMATES FOR TOPOLOGICAL-HYDROGRAPH INPUT.

    USGS Publications Warehouse

    Karlinger, Michael R.; Guertin, D. Phillip; Troutman, Brent M.

    1988-01-01

    Physiographic, hydrologic, and rainfall data from 18 small drainage basins in semiarid, central Wyoming were used to calibrate topological, unit-hydrograph models for celerity, the average rate of travel of a flood wave through the basin. The data set consisted of basin characteristics and hydrologic data for the 18 basins and rainfall data for 68 storms. Calibrated values of celerity and peak discharges subsequently were regressed as a function of the basin characteristics and excess rainfall volume. Predicted values obtained in this way can be used as input for estimating hydrographs in ungaged basins. The regression models included ordinary least-squares and seemingly unrelated regression. This latter regression model jointly estimated the celerity and peak discharge.

  12. Dual motion valve with single motion input

    NASA Technical Reports Server (NTRS)

    Belew, Robert (inventor)

    1987-01-01

    A dual motion valve includes two dual motion valve assemblies with a rotary input which allows the benefits of applying both rotary and axial motion to a rotary sealing element with a plurality of ports. The motion of the rotary sealing element during actuation provides axial engagement of the rotary sealing element with a stationary valve plate which also has ports. Fluid passages are created through the valve when the ports of the rotary sealing element are aligned with the ports of the stationary valve plate. Alignment is achieved through rotation of the rotary sealing element with respect to the stationary valve plate. The fluid passages provide direct paths which minimize fluid turbulence created in the fluid as it passes through the valve.

  13. Depth imaging of offset vertical seismic profile data

    SciTech Connect

    Amundsen, L.; Arntsen, B. [Statoil Research Center, Postuttak, Trondheim, (Norway); Mittet, R. [IKU Petroleum Research, Trondheim (Norway)

    1993-11-01

    Depth migration consists of two different steps: wavefield extrapolation and imaging. The wave propagation is firmly founded on a mathematical frame-work, and is simulated by solving different types of wave equations, dependent on the physical model under investigation. In contrast, the imaging part of migration is usually based on ad hoc ``principles``, rather than on a physical model with an associated mathematical expression. The imaging is usually performed using the U/D concept of Claerbout (1971), which states that reflectors exist at points in the subsurface where the first arrival of the downgoing wave is time-coincident with the upgoing wave. Inversion can, as with migration, be divided into the two steps of wavefield extrapolation and imaging. In contrast to the imaging principle in migration, imaging in inversion follows from the mathematical formulation of the problem. The image with respect to the bulk modulus (or velocity) perturbations is proportional to the correlation between the time derivatives of a forward-propagated field and a backward-propagated residual field (Lailly 1984; Tarantola 1984). The authors assume a physical model in which the wave propagation is governed by the 2D acoustic wave equation. The wave equation is solved numerically using an efficient finite difference scheme, making simulations in realistically sized models feasible. The two imaging concepts of migration and inversion are tested and compared in depth imaging from a synthetic offset vertical seismic profile section. In order to test the velocity sensitivity of the algorithms, two erroneous input velocity models are tested. The authors find that the algorithm founded on inverse theory is less sensitive to velocity errors than depth migration using the more ad hoc U/D imaging principle.

  14. Input\\/output characteristics of scalable parallel applications

    Microsoft Academic Search

    Phyllis E. Crandall; Ruth A. Aydt; Andrew A. Chien; Daniel A. Reed

    1995-01-01

    Rapid increases in computing and communication performance are exacerbating the long-standing problem of performance-limited input\\/output. Indeed, for many otherwise scalable parallel applications. input\\/output is emerging as a major performance bottleneck. The design of scalable input\\/output systems depends critically on the input\\/output requirements and access patterns for this emerging class of large-scale parallel applications. However, hard data on the behavior of

  15. A Comparison Between Tilt-input and Facial Tracking as Input Methods for Mobile Games

    E-print Network

    MacKenzie, Scott

    effort in advancing the state of the art in graphics and themes for gameplay, less interest is directed drawback of touch input for mobile games is the lack of tactile feedback and proprioception. While on a flat touch-sensing surface is problematic. The lack of a tactile sense can be mitigated (somewhat

  16. Prediction-based stabilization of linear systems subject to input-dependent input delay of

    E-print Network

    Boyer, Edmond

    .g. by modeling this dependence as D(u) D(t) (or even by a constant average value D) and by asking the controller being implicitly related to past values of the input via an integral model. This situation engine [17] and exhaust line [13], heat collector plant [32], blending in liquid or solid networks [12

  17. Exergetic Assessment for Resources Input and Environmental Emissions by Chinese Industry during 1997–2006

    PubMed Central

    Zhang, Bo; Peng, Beihua; Liu, Mingchu

    2012-01-01

    This paper presents an overview of the resources use and environmental impact of the Chinese industry during 1997–2006. For the purpose of this analysis the thermodynamic concept of exergy has been employed both to quantify and aggregate the resources input and the environmental emissions arising from the sector. The resources input and environmental emissions show an increasing trend in this period. Compared with 47568.7?PJ in 1997, resources input in 2006 increased by 75.4% and reached 83437.9?PJ, of which 82.5% came from nonrenewable resources, mainly from coal and other energy minerals. Furthermore, the total exergy of environmental emissions was estimated to be 3499.3?PJ in 2006, 1.7 times of that in 1997, of which 93.4% was from GHG emissions and only 6.6% from “three wastes” emissions. A rapid increment of the nonrenewable resources input and GHG emissions over 2002–2006 can be found, owing to the excessive expansion of resource- and energy-intensive subsectors. Exergy intensities in terms of resource input intensity and environmental emission intensity time-series are also calculated, and the trends are influenced by the macroeconomic situation evidently, particularly by the investment-derived economic development in recent years. Corresponding policy implications to guide a more sustainable industry system are addressed. PMID:22973176

  18. Exergetic assessment for resources input and environmental emissions by Chinese industry during 1997-2006.

    PubMed

    Zhang, Bo; Peng, Beihua; Liu, Mingchu

    2012-01-01

    This paper presents an overview of the resources use and environmental impact of the Chinese industry during 1997-2006. For the purpose of this analysis the thermodynamic concept of exergy has been employed both to quantify and aggregate the resources input and the environmental emissions arising from the sector. The resources input and environmental emissions show an increasing trend in this period. Compared with 47568.7?PJ in 1997, resources input in 2006 increased by 75.4% and reached 83437.9?PJ, of which 82.5% came from nonrenewable resources, mainly from coal and other energy minerals. Furthermore, the total exergy of environmental emissions was estimated to be 3499.3?PJ in 2006, 1.7 times of that in 1997, of which 93.4% was from GHG emissions and only 6.6% from "three wastes" emissions. A rapid increment of the nonrenewable resources input and GHG emissions over 2002-2006 can be found, owing to the excessive expansion of resource- and energy-intensive subsectors. Exergy intensities in terms of resource input intensity and environmental emission intensity time-series are also calculated, and the trends are influenced by the macroeconomic situation evidently, particularly by the investment-derived economic development in recent years. Corresponding policy implications to guide a more sustainable industry system are addressed. PMID:22973176

  19. Design Impacts of Stochastically-Varying Input Parameters on Advanced Thermoelectric Conversion

    SciTech Connect

    Hendricks, Terry J.; Karri, Naveen K.

    2007-07-18

    Advanced, direct thermal energy conversion technologies are receiving increased research attention in order to recover waste thermal energy in advanced vehicles and industrial processes. Advanced thermoelectric (TE) systems necessarily require integrated system-level analyses to establish accurate optimum system designs. Past system-level design and analysis has relied on well-defined deterministic input parameters even though many critically important environmental and system design parameters in the above mentioned applications are often randomly variable, sometimes according to complex relationships, rather than discrete, well-known deterministic variables. This work describes new research and development creating techniques and capabilities for probabilistic design and analysis of advanced TE power generation systems to quantify the effects of randomly uncertain design inputs in determining more robust optimum TE system designs and expected outputs. Selected case studies involving stochastic TE .material properties and coupled multi-variable stochasticity in key environmental and design parameters are presented and discussed to demonstrate key impacts from considering stochastic design inputs on the TE design optimization process. Critical findings show that: 1) stochastic Gaussian input distributions may produce Gaussian or non-Gaussian outcome probability distributions for critical TE design parameters, and 2) probabilistic input considerations can create design effects that warrant significant modifications to deterministically-derived optimum TE system designs. Magnitudes and directions of these design modifications are quantified for selected TE system design analysis cases.

  20. Long-term atmospheric nutrient inputs to the Eastern Mediterranean: sources, solubility and comparison with riverine inputs

    NASA Astrophysics Data System (ADS)

    Koçak, M.; Kubilay, N.; Tu?rul, S.; Mihalopoulos, N.

    2010-07-01

    Aerosol and rain samples were collected at a rural site located on the coastline of the Eastern Mediterranean, Erdemli, Turkey between January 1999 and December 2007. Riverine sampling was carried out at five Rivers (Ceyhan, Seyhan, Göksu, Berdan and Lamas) draining into the Northeastern Levantine Basin (NLB) between March 2002 and July 2007. Samples were analyzed for macronutrients of phosphate, silicate, nitrate and ammonium (PO43-, Sidiss, NO3- and NH4+). Phosphate and silicate in aerosol and rainwater showed higher and larger variation during the transitional period (March-May, September) when air flows predominantly originate from North Africa and Middle East/Arabian Peninsula. Deficiency of alkaline material were found to be the main reason of the acidic rain events whilst high pH values (>7) were associated with high Sidiss concentrations due to sporadic dust events. In general, lowest nitrate and ammonium concentrations in aerosol and rainwater were associated with air flow from the Mediterranean Sea. Unlike NO3- and NH4+ (Dissolved Inorganic Nitrogen, DIN), there were statistical differences for PO43- and Sidiss solubilities in sea-water and pure-water. Solubilities of PO43- and Sidiss were found to be related with air mass back trajectories and pH. Comparison of atmospheric with riverine fluxes demonstrated that DIN and PO43- fluxes to NLB were dominated by atmosphere (~90% and ~60% respectively) whereas the input of Si was mainly derived from riverine runoff (~90%). N/P ratios (atmosphere ~233; riverine ~28) revealed that NLB receives excessive amounts of DIN and this unbalanced P and N inputs may provoke even more phosphorus deficiency. Molar Si/N ratios (atmosphere + riverine) suggested Si limitation which might cause a switch from diatom dominated phytoplankton communities to non-siliceous populations in NLB.