WorldWideScience

Sample records for twist contour analysis

  1. Blind analysis results of the TWIST experiment

    CERN Document Server

    Hillairet, A; Bueno, J F; Davydov, Y I; Depommier, P; Faszer, W; Fujiwara, M C; Gagliardi, C A; Gaponenko, A; Grossheim, A; Gill, D R; Gumplinger, P; Hasinoff, M D; Henderson, R S; Hu, J; Koetke, D D; MacDonald, R P; Marshall, G M; Mathie, E W; Mischke, R E; Olchanski, K; Olin, A; Openshaw, R; Poutissou, J -M; Poutissou, R; Selivanov, V; Sheffer, G; Shin, B; Stanislaus, T D S; Tacik, R; Tribble, R E

    2010-01-01

    The TRIUMF Weak Interaction Symmetry Test (TWIST) experiment was designed to test the standard model at high precision in the purely leptonic decay of polarized muons. A general four-fermion interaction model is used to describe the muon decay. TWIST measures three of the four muon decay parameters of this model, $\\rho$, $\\delta$ and $P_{\\mu}^{\\pi} \\xi$, from the shape of the momentum-angle spectrum. The results of this model independent approach are compared to the standard model predictions and used to constrain new physics. Our collaboration has finalized the blind analysis of the final experimental data taken in 2006 and 2007. This analysis mostly reached our goal of a precision of an order of magnitude improvement over the pre-TWIST measurements.

  2. Contour fractal analysis of grains

    Science.gov (United States)

    Guida, Giulia; Casini, Francesca; Viggiani, Giulia MB

    2017-06-01

    Fractal analysis has been shown to be useful in image processing to characterise the shape and the grey-scale complexity in different applications spanning from electronic to medical engineering (e.g. [1]). Fractal analysis consists of several methods to assign a dimension and other fractal characteristics to a dataset describing geometric objects. Limited studies have been conducted on the application of fractal analysis to the classification of the shape characteristics of soil grains. The main objective of the work described in this paper is to obtain, from the results of systematic fractal analysis of artificial simple shapes, the characterization of the particle morphology at different scales. The long term objective of the research is to link the microscopic features of granular media with the mechanical behaviour observed in the laboratory and in situ.

  3. Watt loss in three-phase transformers with circular and hexagonal forming contours of twisted spatial magnetic core rods

    Directory of Open Access Journals (Sweden)

    E.A. Avdieieva

    2014-04-01

    Full Text Available For spatial three-phase axial electromagnetic systems with circular and hexagonal cross-section configurations of twisted butt-end magnetic core rods, analytical dependences for optimal geometrical relations determination over the transformer minimum watt loss criterion are obtained, comparative analysis of the systems energy efficiency made.

  4. Analysis of CVC roll contour and determination of roll crown

    Institute of Scientific and Technical Information of China (English)

    Guang Xu; Xianjun Liu; Jiarong Zhao; Junwei Xiong

    2007-01-01

    Mathematical analysis of continuous variable crown (CVC) roll contour used in CSP production line was conducted and the roll contour function of CVC roll was obtained. The validation with actual CVC roll contour shows that the calculation values of the roll contour function and the actual roll contour parameters given by equipment provider are the same, which proves that the roll contour function of CVC rolls given in this article is correct. The nonlinear relationship between the roll crown of CVC rolls and roll shift amounts was deduced. The concept of crown extremum was given.

  5. Refined contour analysis of giant unilamellar vesicles

    Science.gov (United States)

    Pécréaux, J.; Döbereiner, H.-G.; Prost, J.; Joanny, J.-F.; Bassereau, P.

    2004-03-01

    The fluctuation spectrum of giant unilamellar vesicles is measured using a high-resolution contour detection technique. An analysis at higher q vectors than previously achievable is now possible due to technical improvements of the experimental setup and of the detection algorithm. The global fluctuation spectrum is directly fitted to deduce the membrane tension and the bending modulus of lipid membranes. Moreover, we show that the planar analysis of fluctuations is valid for spherical objects, even at low wave vectors. Corrections due to the integration time of the video camera and to the section of a 3D object by the observation plane are introduced. A precise calculation of the error bars has been done in order to provide reliable error estimate. Eventually, using this technique, we have measured bending moduli for EPC, SOPC and \\chem{SOPC:CHOL} membranes confirming previously published values. An interesting application of this technique can be the measurement of the fluctuation spectra for non-equilibrium membranes, such as “active membranes”.

  6. On the performance analysis of Savonius rotor with twisted blades

    Energy Technology Data Exchange (ETDEWEB)

    Saha, U.K.; Rajkumar, M. Jaya [Department of Mechanical Engineering, Indian Institute of Technology Guwahati, Guwahati-781 039 (India)

    2006-09-15

    The present investigation is aimed at exploring the feasibility of twisted bladed Savonius rotor for power generation. The twisted blade in a three-bladed rotor system has been tested in a low speed wind tunnel, and its performance has been compared with conventional semicircular blades (with twist angle of 0{sup o}). Performance analysis has been made on the basis of starting characteristics, static torque and rotational speed. Experimental evidence shows the potential of the twisted bladed rotor in terms of smooth running, higher efficiency and self-starting capability as compared to that of the conventional bladed rotor. Further experiments have been conducted in the same setup to optimize the twist angle. (author)

  7. A Stylistic Analysis of Register Theory in Oliver Twist

    Institute of Scientific and Technical Information of China (English)

    刘鑫

    2015-01-01

    Stylistic analysis refers to the linguistic approach to literature.Stylistics will mainly focus on the register theory,taking Charles Dickens' masterpiece Oliver Twist as a good example to demonstrate how the register theory is embodied in the work.

  8. A Stylistic Analysis of Register Theory in Oliver Twist

    Institute of Scientific and Technical Information of China (English)

    刘鑫

    2015-01-01

    Stylistic analysis refers to the linguistic approach to literature.Stylistics will mainly focus on the register theory,taking Charles Dickens’ masterpiece Oliver Twist as a good example to demonstrate how the register theory is embodied in the work.

  9. Analysis of gun barrel rifling twist

    Science.gov (United States)

    Sun, Jia; Chen, Guangsong; Qian, Linfang; Liu, Taisu

    2017-05-01

    Aiming at the problem of gun barrel rifling twist, the constraint relation between rifling and projectile is investigated. The constraint model of rifling and projectile is established and the geometric relation between the twist and the motion of projectile is analyzed. Based on the constraint model, according to the rotating band that is fired, the stress and the motion law of the rotating band in bore are analyzed. The effects to rotating band (double rotating band or wide driving band) caused by different rifling (rib rifling, increasing rifling and combined rifling) are also investigated. The model is demonstrated by several examples. The results of numerical examples and the constraint mode show that the uncertainty factors will be brought in the increasing rifling and combined rifling during the projectile move in the bore. According to the amplitude and the strength of the twist acting on rotating band, the steady property of rotational motion of the projectile, the rib rifling is a better choose.

  10. Wound Image Analysis Using Contour Evolution

    Directory of Open Access Journals (Sweden)

    K. Sundeep Kumar

    2014-05-01

    Full Text Available The aim of the algorithm described in this paper is to segment wound images from the normal and classify them according to the types of the wound. The segmentation of wounds extravagates color representation, which has been followed by an algorithm of grayscale segmentation based on the stack mathematical approach. Accurate classification of wounds and analyzing wound healing process is a critical task for patient care and health cost reduction at hospital. The tissue uniformity and flatness leads to a simplified approach but requires multispectral imaging for enhanced wound delineation. Contour Evolution method which uses multispectral imaging replaces more complex tools such as, SVM supervised classification, as no training step is required. In Contour Evolution, classification can be done by clustering color information, with differential quantization algorithm, the color centroids of small squares taken from segmented part of the wound image in (C1,C2 plane. Where C1, C2 are two chrominance components. Wound healing is identified by measuring the size of the wound through various means like contact and noncontact methods of wound. The wound tissues proportion is also estimated by a qualitative visual assessment based on the red-yellow-black code. Moreover, involving all the spectral response of the tissue and not only RGB components provides a higher discrimination for separating healed epithelial tissue from granulation tissue.

  11. Analysis of Cohesion inOliver Twist

    Institute of Scientific and Technical Information of China (English)

    程文文

    2016-01-01

    Cohesion is an important concept in the study of stylistics. This thesis aims to study the applications of cohesion in the Charles Dicken’ world-famous novelOliver Twist, including both the grammatical and lexical cohesive devices in the work.

  12. Active contour model based on force field analysis

    Institute of Scientific and Technical Information of China (English)

    HOU Zhi-qiang; HAN Chong-zhao

    2006-01-01

    The traditional snake initial contour should be close to the true boundary of an object of interest in an image;otherwise,an incorrect result will be obtained.Next,active contours have difficulties progressing into boundary concavities.Moreover,the traditional snake as well as almost all of its improved methods can be easily obtained from the local minimum because snake models are nonconvex.An active contour model based on force field analysis (FFA),namely,FFA snake model,is presented in this paper.Based on analyzing force distribution rules of the distance potential force field,a standard is introduced here to distinguish the false one from contour points.The result is not considered as the final solution when the snake energy is minimal.Furthermore,estimation and calculation should be made according to the established standard;only then can the result be considered final.Thus,the snake is prevented from running into the local minimum.The simulation results show that the FFA snake model has a large capture range and can move a snake into the boundary concavities,and that it is able to obtain the object of interest's contour precisely.Compared with the gradient vector flow snake,this new model has a low computational cost.

  13. Three-dimensional finite element analysis of critical pre-twist strain angle for torsional axis

    Institute of Scientific and Technical Information of China (English)

    ZHOU Guo-feng; LI Xiao-yan; SHI Yao-wu; XU Bin-shi

    2005-01-01

    A three-dimensional elasto-plastic finite element analysis of pre-twist process for a torsional axis made of 45GrNiMoVA steel, was carried out using a commercial finite element analysis code, MSC MARC 2001. The results show that the critical pre-twist strain angle is 0. 027 rad and the maximum elastic shear stress after pre-twist is 1 694 MPa for the torsional axis.

  14. Analysis list: Twist1 [Chip-atlas[Archive

    Lifescience Database Archive (English)

    Full Text Available Twist1 Embryo,Neural + mm9 http://dbarchive.biosciencedbc.jp/kyushu-u/mm9/target/Tw...ist1.1.tsv http://dbarchive.biosciencedbc.jp/kyushu-u/mm9/target/Twist1.5.tsv http://dbarchive.biosciencedbc....jp/kyushu-u/mm9/target/Twist1.10.tsv http://dbarchive.biosciencedbc.jp/kyushu-u/mm9/colo/Twist1.Embryo.tsv,http://dbarchive.bioscien...cedbc.jp/kyushu-u/mm9/colo/Twist1.Neural.tsv http://dbarchive.bioscience...dbc.jp/kyushu-u/mm9/colo/Embryo.gml,http://dbarchive.biosciencedbc.jp/kyushu-u/mm9/colo/Neural.gml ...

  15. Surface Perception from Local Analysis of Texture and Contour.

    Science.gov (United States)

    1980-02-01

    Gibson, 1971; Kennedy, 19741 or a learned skill of interpretation analogous to reading, subject to cultural convention (e.g., [ Arnheim , 19541...contours, highlights, and shading edges tell us of the local Gaussian curvature in some cases. 4 t . SStevens I102 References REFERENCES Arnheim . R

  16. Let's Twist Again: A High-Frequency Event-Study Analysis of Operation Twist and Its Implications for QE2 [with Comments and Discussion

    National Research Council Canada - National Science Library

    ERIC T. SWANSON; LUCREZIA REICHLIN; JONATHAN H. WRIGHT

    2011-01-01

    This paper undertakes a modern event-study analysis of Operation Twist and uses its estimated effects to assess what should be expected for the recent policy of quantitative easing by the Federal Reserve, dubbed "QE2...

  17. Statistical Modeling Approach to Quantitative Analysis of Interobserver Variability in Breast Contouring

    Energy Technology Data Exchange (ETDEWEB)

    Yang, Jinzhong, E-mail: jyang4@mdanderson.org [Department of Radiation Physics, The University of Texas MD Anderson Cancer Center, Houston, Texas (United States); Woodward, Wendy A.; Reed, Valerie K.; Strom, Eric A.; Perkins, George H.; Tereffe, Welela; Buchholz, Thomas A. [Department of Radiation Oncology, The University of Texas MD Anderson Cancer Center, Houston, Texas (United States); Zhang, Lifei; Balter, Peter; Court, Laurence E. [Department of Radiation Physics, The University of Texas MD Anderson Cancer Center, Houston, Texas (United States); Li, X. Allen [Department of Radiation Oncology, Medical College of Wisconsin, Milwaukee, Wisconsin (United States); Dong, Lei [Department of Radiation Physics, The University of Texas MD Anderson Cancer Center, Houston, Texas (United States); Scripps Proton Therapy Center, San Diego, California (United States)

    2014-05-01

    Purpose: To develop a new approach for interobserver variability analysis. Methods and Materials: Eight radiation oncologists specializing in breast cancer radiation therapy delineated a patient's left breast “from scratch” and from a template that was generated using deformable image registration. Three of the radiation oncologists had previously received training in Radiation Therapy Oncology Group consensus contouring for breast cancer atlas. The simultaneous truth and performance level estimation algorithm was applied to the 8 contours delineated “from scratch” to produce a group consensus contour. Individual Jaccard scores were fitted to a beta distribution model. We also applied this analysis to 2 or more patients, which were contoured by 9 breast radiation oncologists from 8 institutions. Results: The beta distribution model had a mean of 86.2%, standard deviation (SD) of ±5.9%, a skewness of −0.7, and excess kurtosis of 0.55, exemplifying broad interobserver variability. The 3 RTOG-trained physicians had higher agreement scores than average, indicating that their contours were close to the group consensus contour. One physician had high sensitivity but lower specificity than the others, which implies that this physician tended to contour a structure larger than those of the others. Two other physicians had low sensitivity but specificity similar to the others, which implies that they tended to contour a structure smaller than the others. With this information, they could adjust their contouring practice to be more consistent with others if desired. When contouring from the template, the beta distribution model had a mean of 92.3%, SD ± 3.4%, skewness of −0.79, and excess kurtosis of 0.83, which indicated a much better consistency among individual contours. Similar results were obtained for the analysis of 2 additional patients. Conclusions: The proposed statistical approach was able to measure interobserver variability quantitatively

  18. Brief Analysis of the Semantic Deviation in Oliver Twist

    Institute of Scientific and Technical Information of China (English)

    黄二靓

    2016-01-01

    As one of the foremost critical realist writers of the Victorian era, Charles Dickens is adept at using language to create all kinds of characters in a humorous or ironic tone. Therefore he received massive popularity for his unique style in storytelling. Oliver Twist is one of Charles Dickens's masterpieces and also the most appropriate choice for the stylistic study on Charles Dickens. This thesis endeavors to explore the aesthetic effect of semantic deviation appearing in Oliver Twist so that we can have a better comprehension about the excellent writing skill of Charles Dickens.

  19. Stability Analysis of The Twisted Superconducting Semilocal Strings

    CERN Document Server

    Garaud, Julien

    2007-01-01

    We study the stability properties of the twisted vortex solutions in the semilocal Abelian Higgs model with a global $\\mathbf{SU}(2)$ invariance. This model can be viewed as the Weinberg-Salam theory in the limit where the non-Abelian gauge field decouples, or as a two component Ginzburg-Landau theory. The twisted vortices are characterized by a constant global current ${\\cal I}$, and for ${\\cal I}\\to 0$ they reduce to the semilocal strings, that is to the Abrikosov-Nielsen-Olesen vortices embedded into the semilocal model. Solutions with ${\\cal I}\

  20. Details of Side Load Test Data and Analysis for a Truncated Ideal Contour Nozzle and a Parabolic Contour Nozzle

    Science.gov (United States)

    Ruf, Joseph H.; McDaniels, David M.; Brown, Andrew M.

    2010-01-01

    Two cold flow subscale nozzles were tested for side load characteristics during simulated nozzle start transients. The two test article contours were a truncated ideal and a parabolic. The current paper is an extension of a 2009 AIAA JPC paper on the test results for the same two nozzle test articles. The side load moments were measured with the strain tube approach in MSFC s Nozzle Test Facility. The processing techniques implemented to convert the strain gage signals into side load moment data are explained. Nozzle wall pressure profiles for separated nozzle flow at many NPRs are presented and discussed in detail. The effect of the test cell diffuser inlet on the parabolic nozzle s wall pressure profiles for separated flow is shown. The maximum measured side load moments for the two contours are compared. The truncated ideal contour s peak side load moment was 45% of that of the parabolic contour. The calculated side load moments, via mean-plus-three-standard-deviations at each nozzle pressure ratio, reproduced the characteristics and absolute values of measured maximums for both contours. The effect of facility vibration on the measured side load moments is quantified and the effect on uncertainty is calculated. The nozzle contour designs are discussed and the impact of a minor fabrication flaw in the nozzle contours is explained.

  1. PERFORMANCE ANALYSIS OF A HELICAL SAVONIUS ROTOR WITHOUT SHAFT AT 45° TWIST ANGLE USING CFD

    Directory of Open Access Journals (Sweden)

    Bachu Deb

    2013-06-01

    Full Text Available Helical Savonius rotor exhibits better performance characteristics at all the rotor angles compared to conventional Savonius rotor. However studies related to the performance measurement and flow physics of such rotor are very scarce. Keeping this in view, in this paper, a three dimensional Computational Fluid Dynamics analysis using commercial Fluent 6.2 software was done to predict the performance of a two-bucket helical Savonius rotor without shaft and with end plates in a complete cycle of rotation. A two-bucket helical Savonius rotor having height of 60 cm and diameter of 17 cm with 45° bucket twist angle was designed using Gambit. The buckets were connected at the top and bottom circular end plates, which are 1.1 times the rotor diameter. The k-ε turbulence model with second order upwind discretization scheme was adopted with standard wall condition. Power coefficients (Cp and torque coefficients (Ct at different tip speed ratios were evaluated at different rotor angles. From the investigation, it was observed that power coefficient increased with increase of tip speed ratio up to an optimum limit, but then decreased even further tip speed ratio was increased. Further investigation was done on the variations of Cp & Ct in a complete cycle of rotation from 0° to 360° in a step of 45° rotor corresponding to the optimum tip speed ratio. The value of Cp at all the rotor angles is positive. Moreover, velocity magnitude contours were analyzed for each rotor angle and it could be concluded that high aerodynamic torque and power can be expected when the rotor is positioned at 45º & 90º with respect to incoming flow.

  2. PERFORMANCE ANALYSIS OF A HELICAL SAVONIUS ROTOR WITHOUT SHAFT AT 45° TWIST ANGLE USING CFD

    Directory of Open Access Journals (Sweden)

    Bachu Deb

    2013-01-01

    Full Text Available Helical Savonius rotor exhibits better performance characteristics at all the rotor angles compared to conventional Savonius rotor. However studies related to the performance measurement and flow physics of such rotor are very scarce. Keeping this in view, in this paper, a three dimensional Computational Fluid Dynamics analysis using commercial Fluent 6.2 software was done to predict the performance of a two-bucket helical Savonius rotor without shaft and with end plates in a complete cycle of rotation. A two-bucket helical Savonius rotor having height of 60 cm and diameter of 17 cm with 45° bucket twist angle was designed using Gambit. The buckets were connected at the top and bottom circular end plates, which are 1.1 times the rotor diameter. The k- ε turbulence model with second order upwind discretization scheme was adopted with standard wall condition. Power coefficients (Cp and torque coefficients (Ct at different tip speed ratios were evaluated at different rotor angles. From the investigation, it was observed that power coefficient increased with increase of tip speed ratio up to an optimum limit, but then decreased even further tip speed ratio was increased. Further investigation was done on the variations of Cp & Ct in a complete cycle of rotation from 0° to 360° in a step of 45° rotor corresponding to the optimum tip speed ratio. The value of Cp at all the rotor angles is positive. Moreover, velocity magnitude contours were analyzed for each rotor angle and it could be concluded that high aerodynamic torque and power can be expected when the rotor is positioned at 45º & 90º with respect to incoming flow.

  3. Analysis of the British Industrial Revolution in cinema: Oliver Twist

    OpenAIRE

    Fuente Diez, Óscar

    2015-01-01

    La Revolución Industrial británica fue un fenómeno histórico que incluso a día de hoy continúa atrayendo miradas. Sus dimensiones fueron tales que actualmente sus consecuencias aún son visibles. El objetivo de este proyecto es analizar el impacto social de la Revolución Industrial británica y las causas que llevaron a este punto como retrata Oliver Twist, la película seleccionada. Desde la perspectiva de las injusticias laborales y las desigualdades sociales, el estudio se centra en las conse...

  4. Autonomic Nervous System Responses to Concussion: Arterial Pulse Contour Analysis

    Directory of Open Access Journals (Sweden)

    Michael F La Fountaine

    2016-02-01

    Full Text Available The arterial pulse wave (APW has a distinct morphology whose contours reflect dynamics in cardiac function and peripheral vascular tone as a result of sympathetic nervous system (SNS control. With a transition from rest to increased metabolic demand, the expected augmentation of SNS outflow will not only affect arterial blood pressure and heart rate, it will also induce changes to the contours of the APW. Following a sports concussion, a transient state cardiovascular autonomic dysfunction is present. How this state affects the APW, has yet to be described. A prospective, parallel-group study on cardiovascular autonomic control (i.e., digital electrocardiogram and continuous beat-to-beat blood pressure was performed in the seated upright position in ten athletes with concussion and 7 non-injured control athletes. Changes in APW were compared at rest and during the first 60 seconds (F60 of an isometric handgrip test (IHGT in concussed athletes and non-injured controls within 48 hours (48hr and 1 week (1wk of injury. The concussion group was further separated by the length of time until they were permitted to return to play (RTP>1wk; RTP≤1wk. SysSlope, an indirect measurement of stroke volume, was significantly lower in the concussion group at rest and during F60 at 48hr and 1wk; a paradoxical decline in SysSlope occurred at each visit during the transition from rest to IHGT F60. The RTP>1wk group had lower SysSlope (405±200; 420±88; 454±236 mmHg/s, respectively at rest 48hr compared to the RTP≤1wk and controls. Similarly at 48hr rest, several measurements of arterial stiffness were abnormal in RTP>1wk compared to RTP≤1wk and controls: Peak-to-Notch Latency (0.12±0.04; 0.16±0.02; 0.17±0.05, respectively, Notch Relative Amplitude (0.70±0.03; 0.71±0.04; 0.66±0.14, respectively and Stiffness Index (6.4±0.2; 5.7±0.4; 5.8±0.5, respectively. Use of APW revealed that concussed athletes have a transient increase in peripheral artery

  5. Characters Segmentation of Cursive Handwritten Words based on Contour Analysis and Neural Network Validation

    Directory of Open Access Journals (Sweden)

    Fajri Kurniawan

    2011-04-01

    Full Text Available This paper presents a robust algorithm to identify the letter boundaries in images of unconstrained handwritten word. The proposed algorithm is based on vertical contour analysis. Proposed algorithm is performed to generate pre-segmentation by analyzing the vertical contours from right to left. The unwanted segmentation points are reduced using neural network validation to improve accuracy of segmentation. The neural network is utilized to validate segmentation points. The experiments are performed on the IAM benchmark database. The results are showing that the proposed algorithm capable to accurately locating the letter boundaries for unconstrained handwritten words.

  6. An Analysis of Chapter XXXI of Oliver Twist From the Perspective of the Violating of Cooperative Principle

    Institute of Scientific and Technical Information of China (English)

    Xu Xiaojuan

    2015-01-01

    Oliver Twist, or The Parish Boy’s Progress (1837), one of Charles Dickens’s masterpieces, has occupied an important position in literature. As a classical work,Oliver Twist has enjoyed great popularity since its publication. Charles Dickens describes, in this work, the tragic life and experiences of the orphan boyOliver Twist who was born in an inhuman workhouse and cruelly treated there in his childhood. This paper attempts to make a detailed analysis of chapter XXXI ofOliver Twist from the perspective of the violating of Cooperative Principle.

  7. Stylistic Analysis on Oliver Twist Written by Charles Dickens

    Institute of Scientific and Technical Information of China (English)

    李文风

    2015-01-01

    《雾都孤儿》是一部批判现实主义小说,是狄更斯主要代表作之一.研究它的作品有很多,但很少有人文体学角度研究它,然而这部作品用了大量的文体学手法.在论文中,作者以小说的第十章为例,从文体学角度评析这篇小说.%Oliver Twist belongs to realistic social critical novel.It is one of the very famous novels written by Dickens. Many books and works have been made to study it.However,few of them study it style,and in this novel,many stylistic means are used.Therefore,in this paper,the author chooses chapter ten as an example to analyses the style of the novel from stylistic view.

  8. An Analysis of the Linguistic Deviation in Chapter X of Oliver Twist

    Institute of Scientific and Technical Information of China (English)

    刘聪

    2013-01-01

    Charles Dickens is one of the greatest critical realist writers of the Victorian Age. In language, he is often compared with William Shakespeare for his adeptness with the vernacular and large vocabulary. Charles Dickens achieved a recognizable place among English writers through the use of the stylistic features in his fictional language. Oliver Twist is the best representative of Charles Dickens’style, which makes it the most appropriate choice for the present stylistic study on Charles Dickens. No one who has ever read the dehumanizing workhouse scenes of Oliver Twist and the dark, criminal underworld life can forget them. This thesis attempts to investigate Oliver Twist through the approach of modern stylistics, particularly the theory of linguistic devia-tion. This thesis consists of an introduction, the main body and a conclusion. The introduction offers a brief summary of the com-ments on Charles Dickens and Chapter X of Oliver Twist, introduces the newly rising linguistic deviation theories, and brings about the theories on which this thesis settles. The main body explores the deviation effects produced from four aspects: lexical deviation, grammatical deviation, graphological deviation, and semantic deviation. It endeavors to show Dickens ’manipulating language and the effects achieved through this manipulation. The conclusion mainly sums up the previous analysis, and reveals the theme of the novel, positive effect of linguistic deviation and significance of deviation application.

  9. Distributed Contour Trees

    Energy Technology Data Exchange (ETDEWEB)

    Morozov, Dmitriy; Weber, Gunther H.

    2014-03-31

    Topological techniques provide robust tools for data analysis. They are used, for example, for feature extraction, for data de-noising, and for comparison of data sets. This chapter concerns contour trees, a topological descriptor that records the connectivity of the isosurfaces of scalar functions. These trees are fundamental to analysis and visualization of physical phenomena modeled by real-valued measurements. We study the parallel analysis of contour trees. After describing a particular representation of a contour tree, called local{global representation, we illustrate how di erent problems that rely on contour trees can be solved in parallel with minimal communication.

  10. Flyby Error Analysis Based on Contour Plots for the Cassini Tour

    Science.gov (United States)

    Stumpf, P. W.; Gist, E. M.; Goodson, T. D.; Hahn, Y.; Wagner, S. V.; Williams, P. N.

    2008-01-01

    The maneuver cancellation analysis consists of cost contour plots employed by the Cassini maneuver team. The plots are two-dimensional linear representations of a larger six-dimensional solution to a multi-maneuver, multi-encounter mission at Saturn. By using contours plotted with the dot product of vectors B and R and the dot product of vectors B and T components, it is possible to view the effects delta V on for various encounter positions in the B-plane. The plot is used in operations to help determine if the Approach Maneuver (ensuing encounter minus three days) and/or the Cleanup Maneuver (ensuing encounter plus three days) can be cancelled and also is a linear check of an integrated solution.

  11. Contour Cluster Shape Analysis for Building Damage Detection from Post-earthquake Airborne LiDAR

    Directory of Open Access Journals (Sweden)

    HE Meizhang

    2015-04-01

    Full Text Available Detection of the damaged building is the obligatory step prior to evaluate earthquake casualty and economic losses. It's very difficult to detect damaged buildings accurately based on the assumption that intact roofs appear in laser data as large planar segments whereas collapsed roofs are characterized by many small segments. This paper presents a contour cluster shape similarity analysis algorithm for reliable building damage detection from the post-earthquake airborne LiDAR point cloud. First we evaluate the entropies of shape similarities between all the combinations of two contour lines within a building cluster, which quantitatively describe the shape diversity. Then the maximum entropy model is employed to divide all the clusters into intact and damaged classes. The tests on the LiDAR data at El Mayor-Cucapah earthquake rupture prove the accuracy and reliability of the proposed method.

  12. Genetic Analysis and Mapping of TWH Gene in Rice Twisted Hull Mutant

    Institute of Scientific and Technical Information of China (English)

    LI Jin-bo; XIA Ming-yuan; WAN Bing-liang; DU Xue-shu; ZHA Zhong-ping; YU Da-zhao; QI Hua-xiong

    2009-01-01

    A mutant with twisted hulls was found in a breeding population of rice (Oryza sativa L.). The mutant shows less grain weight and inferior grain quality in addition to twisted hulls. Genetic analysis indicated that the phenotype of mutant was controlled by a single recessive gene (temporarily designated as TWH). To map the TWH gene, an F2 population was generated by crossing the twh mutant to R725, an indica rice variety with normal hulls. For bulked segregant analysis, the bulk of mutant plants was prepared by mixing equal amount of plant tissue from 10 twisted-hull plants and the bulk of normal plants was obtained by pooling equal amount tissue of 10 normal-hull plants. Two hundred and seven pairs of simple sequence repeat (SSR) primers, which are distributed on 12 rice chromosomes, were used for polymorphism analysis of the parents and the two bulks. The TWH locus was initially mapped close to the SSR marker RM526 on chromosome 2. Therefore, further mapping was performed using 50 pairs of SSR primers around the marker RM526. The TWH was delimited between the SSR markers RM14128 and RM208 on the long arm of chromosome 2 at the genetic distances of 1.4 cM and 2.7 cM, respectively. These results provide the foundation for further fine mapping, cloning and functional analysis of the TWH gene.

  13. Twisted light

    CSIR Research Space (South Africa)

    Forbes, A

    2010-12-01

    Full Text Available Research at the Mathematical Optics Group uses "twisted" light to study new quatum-based information security systems. In order to understand the structure of "twisted" light, it is useful to start with an ordinary light beam with zero twist, namely...

  14. Analysis and design of bend-twist coupled wind turbine blades

    DEFF Research Database (Denmark)

    Stäblein, Alexander R.

    2016-01-01

    Bend-twist coupling allows wind turbine blades to self-alleviate sudden inflow changes, as in gusty or turbulent conditions, resulting in reduced ultimate and fatigue loads. If the coupling is introduced by changing the fibre direction of the anisotropic blade material, the assumptions of classical...... beam theory are not necessarily valid. This chapter reviews the effects of anisotropic material on the structural response of beams and identifies those relevant for wind turbine blade analysis. A framework suitable for the structural analysis of wind turbine blades is proposed and guidance...

  15. Characters Segmentation of Cursive Handwritten Words based on Contour Analysis and Neural Network Validation

    Directory of Open Access Journals (Sweden)

    Fajri Kurniawan

    2013-09-01

    Full Text Available This paper presents a robust algorithm to identify the letter boundaries in images of unconstrained handwritten word . The proposed algorithm is based on  vertical  contour  analysis.  Proposed  algorithm  is  performed  to  generate  presegmentation by analyzing the vertical contours from right to left. The unwanted segmentation  points  are  reduced  using  neural  network  validation  to  improve accuracy  of  segmentation.  The  neural  network  is  utilized  to  validate segmentation  points.  The  experiments  are  performed  on  the  IAM  benchmark database.  The  results  are  showing  that  the  proposed  algorithm  capable  to accurately locating the letter boundaries for unconstrained handwritten words.

  16. Automatic diatom identification using contour analysis by morphological curvature scale spaces

    NARCIS (Netherlands)

    Jalba, Andrei C.; Wilkinson, Michael H.F.; Roerdink, Jos B.T.M.; Bayer, Micha M.; Juggins, Stephen

    2005-01-01

    A method for automatic identification of diatoms (single-celled algae with silica shells) based on extraction of features on the contour of the cells by multi-scale mathematical morphology is presented. After extracting the contour of the cell, it is smoothed adaptively, encoded using Freeman chain

  17. Fourier Descriptor Analysis and Unification of Voice Range Profile Contours: Method and Applications

    Science.gov (United States)

    Pabon, Peter; Ternstrom, Sten; Lamarche, Anick

    2011-01-01

    Purpose: To describe a method for unified description, statistical modeling, and comparison of voice range profile (VRP) contours, even from diverse sources. Method: A morphologic modeling technique, which is based on Fourier descriptors (FDs), is applied to the VRP contour. The technique, which essentially involves resampling of the curve of the…

  18. Fourier Descriptor Analysis and Unification of Voice Range Profile Contours: Method and Applications

    Science.gov (United States)

    Pabon, Peter; Ternstrom, Sten; Lamarche, Anick

    2011-01-01

    Purpose: To describe a method for unified description, statistical modeling, and comparison of voice range profile (VRP) contours, even from diverse sources. Method: A morphologic modeling technique, which is based on Fourier descriptors (FDs), is applied to the VRP contour. The technique, which essentially involves resampling of the curve of the…

  19. High resolution mapping of Twist to DNA in Drosophila embryos: Efficient functional analysis and evolutionary conservation

    OpenAIRE

    Ozdemir, Anil; Fisher-Aylor, Katherine I.; Pepke, Shirley; Samanta, Manoj; Dunipace, Leslie; McCue, Kenneth; Zeng, Lucy; Ogawa, Nobuo; Wold, Barbara J; Stathopoulos, Angelike

    2011-01-01

    Cis-regulatory modules (CRMs) function by binding sequence specific transcription factors, but the relationship between in vivo physical binding and the regulatory capacity of factor-bound DNA elements remains uncertain. We investigate this relationship for the well-studied Twist factor in Drosophila melanogaster embryos by analyzing genome-wide factor occupancy and testing the functional significance of Twist occupied regions and motifs within regions. Twist ChIP-seq data efficiently identif...

  20. Stress distribution of new generation of Twisted Files in comparison with ProTaper: A finite element analysis

    Directory of Open Access Journals (Sweden)

    Harsha Pujari

    2013-01-01

    Full Text Available Aim: To compare and evaluate the stress distribution of new generation of Twisted File in comparison with ProTaper under bending or torsional conditions using a finite - element analysis model. Materials and Methods: Two NiTi files, a ProTaper file and the latest generation nickel titanium file which is the Twisted File of similar tip diameter were scanned using White light scanning system. Through this a real size digitized models of the two brands of NiTi instruments were obtained. Then, the outline of the instrument was extracted from the stacks of 3D data in software. Finally a mesh of linear, eight-noded, hexahedral elements was overlaid onto the rendered 3D image. The behavior of the instrument under bending or torsional loads was then analyzed mathematically in the software (ABAQUS V6, 5-1 taking into consideration the non linear mechanical characteristic of NiTi material. The results were expressed as von Mises stresses and were calculated by the von Mises criteria. Results: Higher stress values were seen in Twisted Files than the ProTaper universal, however, the angular deflection was seen to be more in Twisted Files. Conclusion: As more angular deflection was seen in Twisted File it was more flexible than ProTaper Universal but did not have the uniform stress distribution like the ProTaper universal.

  1. Dynamical Twisted Mass Fermions with Light Quarks: Simulation and Analysis Details

    CERN Document Server

    Boucaud, Ph; Farchioni, F; Frezzotti, R; Giménez, V; Herdoiza, G; Jansen, K; Lubicz, V; Michael, C; Münster, G; Palao, D; Rossi, G C; Scorzato, L; Shindler, A; Simula, S; Sudmann, T; Urbach, C; Wenger, U

    2008-01-01

    In a recent paper [hep-lat/0701012] we presented precise lattice QCD results of our European Twisted Mass Collaboration (ETMC). They were obtained by employing two mass-degenerate flavours of twisted mass fermions at maximal twist. In the present paper we give details on our simulations and the computation of physical observables. In particular, we discuss the problem of tuning to maximal twist, the techniques we have used to compute correlators and error estimates. In addition, we provide more information on the algorithm used, the autocorrelation times and scale determination, the evaluation of disconnected contributions and the description of our data by means of chiral perturbation theory formulae.

  2. Contour Tones.

    Science.gov (United States)

    Yip, Moira

    1989-01-01

    Argues that contour tones in East Asian languages behave as melodic units consisting of a root node [upper] dominating a branching specification. It is also argued that, with upper as the tonal root node, no more than two rising or falling tones will contrast underlying. (49 references) (JL)

  3. Contouring a guide to the analysis and display of spatial data

    CERN Document Server

    Watson, Debbie

    2013-01-01

    This unique book is the key to computer contouring, exploring in detail the practice and principles using a personal computer. Contouring allows a three dimensional view in two dimensions and is a fundamental technique to represent spatial data. All aspects of this type of representation are covered including data preparation, selecting contour intervals, interpolation and griding, computing volumes and output and display. Formulated for both the novice and the experienced user, this book initially conducts the reader through a step by step explanation of PC software and its application to per

  4. Properties of twisted ferromagnetic filaments

    Energy Technology Data Exchange (ETDEWEB)

    Belovs, Mihails; Cebers, Andrejs [University of Latvia, Zellu 8, LV-1002 (Latvia)], E-mail: aceb@tesla.sal.lv

    2009-02-01

    The full set of equations for twisted ferromagnetic filaments is derived. The linear stability analysis of twisted ferromagnetic filament is carried out. Two different types of the buckling instability are found - monotonous and oscillatory. The first in the limit of large twist leads to the shape of filament reminding pearls on the string, the second to spontaneous rotation of the filament, which may constitute the working of chiral microengine.

  5. Analysis of Twisting of Cellulose Nanofibrils in Atomistic Molecular Dynamics Simulations

    DEFF Research Database (Denmark)

    Paavilainen, S.; Rog, T.; Vattulainen, I.

    2011-01-01

    We use atomistic molecular dynamics simulations to study the crystal structure of cellulose nanofibrils, whose sizes are comparable with the crystalline parts in commercial nanocellulose. The simulations show twisting, whose rate of relaxation is strongly temperature dependent. Meanwhile, no sign......We use atomistic molecular dynamics simulations to study the crystal structure of cellulose nanofibrils, whose sizes are comparable with the crystalline parts in commercial nanocellulose. The simulations show twisting, whose rate of relaxation is strongly temperature dependent. Meanwhile......, no significant bending or stretching of nanocellulose is discovered. Considerations of atomic-scale interaction patterns bring about that the twisting arises from hydrogen bonding within and between the chains in a fibril....

  6. A novel three-dimensional smile analysis based on dynamic evaluation of facial curve contour

    Science.gov (United States)

    Lin, Yi; Lin, Han; Lin, Qiuping; Zhang, Jinxin; Zhu, Ping; Lu, Yao; Zhao, Zhi; Lv, Jiahong; Lee, Mln Kyeong; Xu, Yue

    2016-02-01

    The influence of three-dimensional facial contour and dynamic evaluation decoding on factors of smile esthetics is essential for facial beauty improvement. However, the kinematic features of the facial smile contour and the contribution from the soft tissue and underlying skeleton are uncharted. Here, the cheekbone-maxilla contour and nasolabial fold were combined into a “smile contour” delineating the overall facial topography emerges prominently in smiling. We screened out the stable and unstable points on the smile contour using facial motion capture and curve fitting, before analyzing the correlation between soft tissue coordinates and hard tissue counterparts of the screened points. Our finding suggests that the mouth corner region was the most mobile area characterizing smile expression, while the other areas remained relatively stable. Therefore, the perioral area should be evaluated dynamically while the static assessment outcome of other parts of the smile contour contribute partially to their dynamic esthetics. Moreover, different from the end piece, morphologies of the zygomatic area and the superior part of the nasolabial crease were determined largely by the skeleton in rest, implying the latter can be altered by orthopedic or orthodontic correction and the former better improved by cosmetic procedures to improve the beauty of smile.

  7. Analysis of Rotman Lens Antenna for Different Substrates for Circular Contour

    Directory of Open Access Journals (Sweden)

    Shruti Vashist

    2014-07-01

    Full Text Available This paper presents a trifocal Rotman lens design approach. The effect due to change of substrate on the circular contour is observed. The shape of the beam contour is taken as circular. Different substrates can be used for the fabrication of the lens. Three different materials have been used to fabricate the lens antenna .A three beam prototype feeding five element antenna array working in ISM band has been simulated using RLD1.7.Effects on the performance of the antenna is observed.

  8. Thermoelastic buckling analysis of pre-twisted functionally graded beams with temperature-dependent material properties

    Science.gov (United States)

    Shenas, Amin Ghorbani; Malekzadeh, Parviz; Ziaee, Sima

    2017-04-01

    As a first endeavor, the thermal buckling behavior of pre-twisted functionally graded (FG) beams with temperature-dependent material properties is investigated. The governing stability equations are derived based on the third-order shear deformation theory (TSDT) in conjunction with the adjacent equilibrium state criterion under the von Kármán's nonlinear kinematic assumptions using the Chebyshev-Ritz method. The Chebyshev polynomials multiplied with some suitable boundary functions are used as the basis functions, which allow one to analyze the beams with different boundary conditions. The extracted system of nonlinear algebraic eigenvalue equations is solved iteratively to obtain the critical temperature rise. The convergence behavior together with accuracy of the solution method and the correctness of formulation are demonstrated through different examples. Then, the influences of the linear and nonlinear variation of the angle of twist along the beam axis, the value of twist angle, length-to-thickness ratio, thickness-to-width ratio, material gradient index and temperature dependence of material properties on the critical temperature rise of the pre-twisted FG beams under different boundary conditions are investigated. It is shown that the pre-twist angle increases the thermal buckling resistance of the pre-twisted FG beams, but the temperature dependence of material properties reduces it.

  9. Twisting Somersault

    CERN Document Server

    Dullin, Holger R

    2015-01-01

    A complete description of twisting somersaults is given using a reduction to a time-dependent Euler equation for non-rigid body dynamics. The central idea is that after reduction the twisting motion is apparent in a body frame, while the somersaulting (rotation about the fixed angular momentum vector in space) is recovered by a combination of dynamic and geometric phase. In the simplest "kick-model" the number of somersaults $m$ and the number of twists $n$ are obtained through a rational rotation number $W = m/n$ of a (rigid) Euler top. This rotation number is obtained by a slight modification of Montgomery's formula [9] for how much the rigid body has rotated. Using the full model with shape changes that take a realistic time we then derive the master twisting-somersault formula: An exact formula that relates the airborne time of the diver, the time spent in various stages of the dive, the numbers $m$ and $n$, the energy in the stages, and the angular momentum by extending a geometric phase formula due to C...

  10. Oliver Twist

    NARCIS (Netherlands)

    Dickens, Charles

    2005-01-01

    Oliver Twist is one of Dickens's most popular novels, with many famous film, television and musical adaptations. It is a classic story of good against evil, packed with humour and pathos, drama and suspense, in which the orphaned Oliver is brought up in a harsh workhouse, and then taken in and

  11. Oliver Twist

    NARCIS (Netherlands)

    Dickens, Charles

    2005-01-01

    Oliver Twist is one of Dickens's most popular novels, with many famous film, television and musical adaptations. It is a classic story of good against evil, packed with humour and pathos, drama and suspense, in which the orphaned Oliver is brought up in a harsh workhouse, and then taken in and explo

  12. VOLUME STUDY WITH HIGH DENSITY OF PARTICLES BASED ON CONTOUR AND CORRELATION IMAGE ANALYSIS

    Directory of Open Access Journals (Sweden)

    Tatyana Yu. Nikolaeva

    2014-11-01

    Full Text Available The subject of study is the techniques of particle statistics evaluation, in particular, processing methods of particle images obtained by coherent illumination. This paper considers the problem of recognition and statistical accounting for individual images of small scattering particles in an arbitrary section of the volume in case of high concentrations. For automatic recognition of focused particles images, a special algorithm for statistical analysis based on contouring and thresholding was used. By means of the mathematical formalism of the scalar diffraction theory, coherent images of the particles formed by the optical system with high numerical aperture were simulated. Numerical testing of the method proposed for the cases of different concentrations and distributions of particles in the volume was performed. As a result, distributions of density and mass fraction of the particles were obtained, and the efficiency of the method in case of different concentrations of particles was evaluated. At high concentrations, the effect of coherent superposition of the particles from the adjacent planes strengthens, which makes it difficult to recognize images of particles using the algorithm considered in the paper. In this case, we propose to supplement the method with calculating the cross-correlation function of particle images from adjacent segments of the volume, and evaluating the ratio between the height of the correlation peak and the height of the function pedestal in the case of different distribution characters. The method of statistical accounting of particles considered in this paper is of practical importance in the study of volume with particles of different nature, for example, in problems of biology and oceanography. Effective work in the regime of high concentrations expands the limits of applicability of these methods for practically important cases and helps to optimize determination time of the distribution character and

  13. A Stylistic Analysis of the Thieves' Language in Oliver Twist%A Stylistic Analysis of the Thieves'Language in Oliver Twist

    Institute of Scientific and Technical Information of China (English)

    侯宇

    2016-01-01

    Charles Dickens is the most outstanding realistic novelists in Victorian Age, and Oliver Twist is one of his representative works. Except Oliver, the hero, the group of thieves appears most frequently through the whole novel and plays an important role not only in effecting Oliver's life experience, but also in showing the reality in the prevailing social. Dickens' successful shaping of the images of the group of thieve relies on their language. This thesis aims to analyze the thieves' language from the stylistics aspect.

  14. Topological Cacti: Visualizing Contour-based Statistics

    Energy Technology Data Exchange (ETDEWEB)

    Weber, Gunther H.; Bremer, Peer-Timo; Pascucci, Valerio

    2011-05-26

    Contours, the connected components of level sets, play an important role in understanding the global structure of a scalar field. In particular their nestingbehavior and topology-often represented in form of a contour tree-have been used extensively for visualization and analysis. However, traditional contour trees onlyencode structural properties like number of contours or the nesting of contours, but little quantitative information such as volume or other statistics. Here we use thesegmentation implied by a contour tree to compute a large number of per-contour (interval) based statistics of both the function defining the contour tree as well asother co-located functions. We introduce a new visual metaphor for contour trees, called topological cacti, that extends the traditional toporrery display of acontour tree to display additional quantitative information as width of the cactus trunk and length of its spikes. We apply the new technique to scalar fields ofvarying dimension and different measures to demonstrate the effectiveness of the approach.

  15. Twisted baskets.

    Science.gov (United States)

    Hermann, Keith; Pratumyot, Yaowalak; Polen, Shane; Hardin, Alex M; Dalkilic, Erdin; Dastan, Arif; Badjić, Jovica D

    2015-02-23

    A preparative procedure for obtaining a pair of twisted molecular baskets, each comprising a chiral framework with either right ((P)-1syn) or left ((M)-1syn) sense of twist and six ester groups at the rim has been developed and optimized. The racemic (P/M)-1syn can be obtained in three synthetic steps from accessible starting materials. The resolution of (P/M)-1syn is accomplished by its transesterification with (1R,2S,5R)-(-)-menthol in the presence of a Ti(IV) catalyst to give diastereomeric 8(P) and 8(M). It was found that dendritic-like cavitands 8(P) and 8(M), in CD2Cl2, undergo self-inclusion ((1)H NMR spectroscopy) with a menthol moiety occupying the cavity of each host. Importantly, the degree of inclusion of the menthol group was ((1)H NMR spectroscopy) found to be greater in the case of 8(P) than 8(M). Accordingly, it is suggested that different folding characteristic of 8(P) and 8(M) ought to affect the physicochemical characteristics of the hosts to permit their effective separation by column chromatography. The absolute configuration of 8(P)/8(M), encompassing right- and left-handed "cups", was determined with the exciton chirality method and also verified in silico (DFT: B3LYP/TZVP). Finally, the twisted baskets are strongly fluorescent due to three naphthalene chromophores, having a high fluorescence quantum yield within the rigid framework of 8(P)/8(M).

  16. Feed-forward active contour analysis for improved brachial artery reactivity testing.

    Science.gov (United States)

    Pugliese, Daniel N; Sehgal, Chandra M; Sultan, Laith R; Reamer, Courtney B; Mohler, Emile R

    2016-08-01

    The object of this study was to utilize a novel feed-forward active contour (FFAC) algorithm to find a reproducible technique for analysis of brachial artery reactivity. Flow-mediated dilation (FMD) is an important marker of vascular endothelial function but has not been adopted for widespread clinical use given its technical limitations, including inter-observer variability and differences in technique across clinical sites. We developed a novel FFAC algorithm with the goal of validating a more reliable standard. Forty-six healthy volunteers underwent FMD measurement according to the standard technique. Ultrasound videos lasting 5-10 seconds each were obtained pre-cuff inflation and at minutes 1 through 5 post-cuff deflation in longitudinal and transverse views. Automated segmentation using the FFAC algorithm with initial boundary definition from three different observers was used to analyze the images to measure diameter/cross-sectional area over the cardiac cycle. The %FMD was calculated for average, minimum, and maximum diameters/areas. Using the FFAC algorithm, the population-specific coefficient of variation (CV) at end-diastole was 3.24% for transverse compared to 9.96% for longitudinal measurements; the subject-specific CV was 15.03% compared to 57.41%, respectively. For longitudinal measurements made via the conventional method, the population-specific CV was 4.77% and subject-specific CV was 117.79%. The intraclass correlation coefficient (ICC) for transverse measurements was 0.97 (95% CI: 0.95-0.98) compared to 0.90 (95% CI: 0.84-0.94) for longitudinal measurements with FFAC and 0.72 (95% CI: 0.51-0.84) for conventional measurements. In conclusion, transverse views using the novel FFAC method provide less inter-observer variability than traditional longitudinal views. Improved reproducibility may allow adoption of FMD testing in a clinical setting. The FFAC algorithm is a robust technique that should be evaluated further for its ability to replace the

  17. Rotation axes analysis of deformed magnesium based on rotation contour contrast in a scanning electron microscope

    Energy Technology Data Exchange (ETDEWEB)

    Kaboli, Shirin; Gauvin, Raynald, E-mail: raynald.gauvin@mcgill.ca

    2015-07-15

    A crystallographic orientation contrast in the form of cross-shaped and intersecting contours was observed in a backscattered electron (BSE) micrograph of deformed magnesium (Mg) grains in a cold field emission scanning electron microscope (CFE-SEM). This contrast was identified as rotation contour contrast (RCC). A model is presented to link the RCC in the BSE micrograph to the channeling contrast in the corresponding channeling pattern. Based on this model, the appearance of the cross-shaped RCC in the BSE micrograph was attributed to the rotation of the crystal about two rotation axes and the RCC was related to a two dimensional angular scan of the corresponding channeling pattern. This model was experimentally validated using the selected area channeling pattern (SACP) technique. The crystallographic directions of the rotation axes were identified using the electron backscatter diffraction (EBSD) technique. - Highlights: • The rotation contour contrast (RCC) was studied in scanning electron microscope (SEM). • The RCC model was developed to link the backscattered electron contrast to the channeling contrast. • The RCC model was validated using the selected area channeling pattern (SACP). • The rotation axes were identified using the electron backscatter diffraction (EBSD)

  18. AN EXACT ANALYSIS OF FORCED THICKNESS-TWIST VIBRATIONS OF MULTI-LAYERED PIEZOELECTRIC PLATES

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    This paper deals with the thickness-twist vibration of a multi-layered rectangular piezoelectric plate of crystals of 6 mm symmetry or polarized ceramics. An exact solution is obtained from the three-dimensional equations of linear piezoelectricity. The solution is useful to the understanding and design of composite piezoelectric devices. A piezoelectric resonator, a piezoelectric transformer, and a piezoelectric generator are analyzed as examples.

  19. Simplifying Massive Contour Maps

    DEFF Research Database (Denmark)

    Arge, Lars; Deleuran, Lasse Kosetski; Mølhave, Thomas;

    2012-01-01

    We present a simple, efficient and practical algorithm for constructing and subsequently simplifying contour maps from massive high-resolution DEMs, under some practically realistic assumptions on the DEM and contours.......We present a simple, efficient and practical algorithm for constructing and subsequently simplifying contour maps from massive high-resolution DEMs, under some practically realistic assumptions on the DEM and contours....

  20. SENSITIVITY ANALYSIS BY ARTIFICIAL NEURAL NETWORK (ANN OF VARIABLES THAT INFLUENCE THE DIAGONAL TWIST IN A PAPERBOARD INDUSTRIAL MACHINE

    Directory of Open Access Journals (Sweden)

    Guinter Neutzling Schneid

    2016-01-01

    Full Text Available The dimensional stability of the paper may change due to middle exchange moisture, releasing the latent stress acquired into the manufacturing process. One result of this tension release is the diagonal curl. This study aims to conduct a sensitivity analysis of the different input’s variables of an industrial paper machine, along with some laboratory measurements, in order to identify the importance in production of paperboard quality control and relate to the property of the paper called twist. A survey was made of the production history, relating to 2012, to observe the products with the highest quality losses. From this, they were correlated with the critical points of measurement profile in the machine cross direction and consequently with the paper. It was found some changes once the variables correlated with twist, referring to the three analyzes of the profile (tender side, middle and drive side. It was revealed, from the sensitivity analysis, that the most important and sensitive variables, respectively for the tender side, middle and drive side, were total flow from the top layer, vapor pressure in the 6th group of drying cylinders and mass flow side of the bottom layer of the formation of paperboard.

  1. Effective Young's modulus of the artificial muscle twisted by fishing lines: Analysis and experiment

    Science.gov (United States)

    Yue, Donghua; Zhang, Xingyi; Zhou, Jun; Zhou, You-He

    2015-09-01

    Artificial muscles transformed by fishing lines or sewing thread, have distinguished advantages, e. g., fast, scalable, nonhysteretic, and long-life, which have been proposed by Haines et al. [Science 343, 868 (2014)]. In this paper, we present a geometrical model to predict the effective Young's modulus of the basic structure that is twisted by three fishing lines with the same diameter. Moreover, series of experiments are carried out to verify the present model, and it is found the theoretical calculations take good agreements with the experimental results.

  2. Analysis of the NovoTwist pen needle in comparison with conventional screw-thread needles.

    Science.gov (United States)

    Aye, Tandy

    2011-11-01

    Administration of insulin via a pen device may be advantageous over a vial and syringe system. Hofman and colleagues introduce a new insulin pen needle, the NovoTwist, to simplify injections to a small group of children and adolescents. Their overall preferences and evaluation of the handling of the needle are reported in the study. This new needle has the potential to ease administration of insulin via a pen device that may increase both the use of a pen device and adherence to insulin therapy.

  3. Target Region Location Based on Texture Analysis and Active Contour Model

    Institute of Scientific and Technical Information of China (English)

    YANG Zhaoxuan; BAI Zhuofu; WU Jiapeng; CHEN Yang

    2009-01-01

    Traditional texture region location methods with Gabor features are often limited in the selection of Gabor filters and fail to deal with the target which contains both texture and non-texture parts.Thus,to solve this problem,a two-step new model was proposed.In the first step,the original features extracted by Gabor filters are applied to training a self-organizing map (SOM) neural network and a novel merging scheme is presented to achieve the clustering.A back propagation (BP) network is used as a classifier to locate the target region approximately.In the second step,Chan-Vese active contour model is applied to detecting the boundary of the target region accurately and morphological processing is used to create a connected domain whose convex hull can cover the target region.In the experiments,the proposed method is demonstrated accurate and robust in localizing target on texture database and practical barcode location system as well.

  4. Twisted aspirin crystals.

    Science.gov (United States)

    Cui, Xiaoyan; Rohl, Andrew L; Shtukenberg, Alexander; Kahr, Bart

    2013-03-06

    Banded spherulites of aspirin have been crystallized from the melt in the presence of salicylic acid either generated from aspirin decomposition or added deliberately (2.6-35.9 mol %). Scanning electron microscopy, X-ray diffraction analysis, and optical polarimetry show that the spherulites are composed of helicoidal crystallites twisted along the growth directions. Mueller matrix imaging reveals radial oscillations in not only linear birefringence, but also circular birefringence, whose origin is explained through slight (∼1.3°) but systematic splaying of individual lamellae in the film. Strain associated with the replacement of aspirin molecules by salicylic acid molecules in the crystal structure is computed to be large enough to work as the driving force for the twisting of crystallites.

  5. Numerical analysis of the three-dimensional cloud cavitating flow around a twisted hydrofoil

    Energy Technology Data Exchange (ETDEWEB)

    Park, Sunho; Hyung Rhee, Shin, E-mail: shr@snu.ac.kr [Department of Naval Architecture and Ocean Engineering, Research Institute of Marine Systems Engineering, Seoul National University, 1 Gwanak-ro, Gwanak-gu, Seoul 151-744 (Korea, Republic of)

    2013-02-15

    Unsteady sheet cavitation on a three-dimensional twisted hydrofoil was studied using a Reynolds-averaged Navier-Stokes simulation technique based on a cell-centered finite volume method. As a verification test of the computational method, the leading edge and mid-chord cavitating flows over a two-dimensional modified NACA66 foil section were simulated for various cavitation numbers and validated against existing experimental data. The cavitation model parameters and numerical schemes were determined by a comparison with the measured pressure distribution. Non-cavitating and cavitating flows around a three-dimensional twisted hydrofoil were simulated with the selected computational method. The computed pressure on the foil and the cavity shedding patterns were validated by comparing these results with existing experimental data. The cavity shedding dynamics due to a re-entrant jet and a side entrant jet were investigated in terms of the cavity shedding cycles. The computed lift force and Strouhal number were compared against existing experimental data. (paper)

  6. Contours, Elevation contour data are a fundamental base map layer for large scale mapping and GIS analysis., Published in 2001, 1:24000 (1in=2000ft) scale, Louisiana State University.

    Data.gov (United States)

    NSGIC GIS Inventory (aka Ramona) — This Contours dataset, published at 1:24000 (1in=2000ft) scale as of 2001. It is described as 'Elevation contour data are a fundamental base map layer for large...

  7. Noninvasive cardiac output determination using applanation tonometry-derived radial artery pulse contour analysis in critically ill patients

    DEFF Research Database (Denmark)

    Compton, Friederike; Wittrock, Marc; Schaefer, Juergen-Heiner

    2008-01-01

    Conventional thermodilution cardiac output (CO) monitoring is limited mainly to intensive care units and operating rooms because it requires the use of invasive techniques. To reduce the potential for complications and to broaden the applicability of hemodynamic monitoring, noninvasive methods...... for CO determination are being sought. Applanation tonometry allows noninvasive CO estimation through pulse contour analysis, but the method has not been evaluated in critically ill patients. We therefore performed noninvasive radial artery applanation tonometry in 49 critically ill medical intensive...... care unit patients and compared CO estimates to invasive CO measurements obtained using a pulmonary artery catheter or the PiCCO transpulmonary thermodilution system. One-hundred-sixteen measurements were performed, and patients were receiving vasopressor support during 78 measurements. When the data...

  8. Ocean Sediment Thickness Contours

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Ocean sediment thickness contours in 200 meter intervals for water depths ranging from 0 - 18,000 meters. These contours were derived from a global sediment...

  9. Tagged Vector Contour (TVC)

    Data.gov (United States)

    Kansas Data Access and Support Center — The Kansas Tagged Vector Contour (TVC) dataset consists of digitized contours from the 7.5 minute topographic quadrangle maps. Coverage for the state is incomplete....

  10. Fairfax County Contours

    Data.gov (United States)

    Federal Emergency Management Agency, Department of Homeland Security — This layer contains contours that were derived from the digital terrain model made up of irregularly spaced mass points and breaklines. The contours are 5 foot...

  11. High Resolution Elevation Contours

    Data.gov (United States)

    Minnesota Department of Natural Resources — This dataset contains contours generated from high resolution data sources such as LiDAR. Generally speaking this data is 2 foot or less contour interval.

  12. Aeroelastic analysis for helicopter rotor blades with time-variable, non-linear structural twist and multiple structural redundancy: Mathematical derivation and program user's manual

    Science.gov (United States)

    Bielawa, R. L.

    1976-01-01

    The differential equations of motion for the lateral and torsional deformations of a nonlinearly twisted rotor blade in steady flight conditions together with those additional aeroelastic features germane to composite bearingless rotors are derived. The differential equations are formulated in terms of uncoupled (zero pitch and twist) vibratory modes with exact coupling effects due to finite, time variable blade pitch and, to second order, twist. Also presented are derivations of the fully coupled inertia and aerodynamic load distributions, automatic pitch change coupling effects, structural redundancy characteristics of the composite bearingless rotor flexbeam - torque tube system in bending and torsion, and a description of the linearized equations appropriate for eigensolution analyses. Three appendixes are included presenting material appropriate to the digital computer program implementation of the analysis, program G400.

  13. Noninvasive cardiac output monitoring during exercise testing: Nexfin pulse contour analysis compared to an inert gas rebreathing method and respired gas analysis.

    Science.gov (United States)

    Bartels, Sebastiaan A; Stok, Wim J; Bezemer, Rick; Boksem, Remco J; van Goudoever, Jeroen; Cherpanath, Thomas G V; van Lieshout, Johannes J; Westerhof, Berend E; Karemaker, John M; Ince, Can

    2011-10-01

    Exercise testing is often used to assess cardiac function during physical exertion to obtain diagnostic information. However, this procedure is limited to measuring the electrical activity of the heart using electrocardiography and intermittent blood pressure (BP) measurements and does not involve the continuous assessment of heart functioning. In this study, we compared continuous beat-to-beat pulse contour analysis to monitor noninvasive cardiac output (CO) during exercise with inert gas rebreathing and respired gas analysis. Nineteen healthy male volunteers were subjected to bicycle ergometry testing with increasing workloads. Cardiac output was deter- mined noninvasively by continuous beat-to-beat pulse contour analysis (Nexfin) and by inert gas rebreathing, and estimated using the respired gas analysis method. The effects of the rebreathing maneuver on heart rate (HR), stroke volume (SV), and CO were evaluated. The CO values derived from the Nexfin- and inert gas rebreathing methods were well correlated (r = 0.88, P gas analysis-derived CO values correlated even better (r = 0.94, P < 0.01) and the limits of agreement were 21.5% with a measurement bias of -0.70 ± 1.6 L/min. At rest, the rebreathing maneuver increased HR by 13 beats/min (P < 0.01), SV remained unaffected (P = 0.7), while CO increased by 1.0 L/min (P < 0.01). Rebreathing did not affect these parameters during exercise. Nexfin continuous beat-to-beat pulse contour analysis is an appropriate method for noninvasive assessment of CO during exercise.

  14. Importance of re-calibration time on pulse contour analysis agreement with thermodilution measurements of cardiac output: a retrospective analysis of intensive care unit patients.

    Science.gov (United States)

    Scully, Christopher G; Gomatam, Shanti; Forrest, Shawn; Strauss, David G

    2016-10-01

    We assessed the effect of re-calibration time on cardiac output estimation and trending performance in a retrospective analysis of an intensive care unit patient population using error grid analyses. Paired thermodilution and arterial blood pressure waveform measurements (N = 2141) from 222 patient records were extracted from the Multiparameter Intelligent Monitoring in Intensive Care II database. Pulse contour analysis was performed by implementing a previously reported algorithm at calibration times of 1, 2, 8 and 24 h. Cardiac output estimation agreement was assessed using Bland-Altman and error grid analyses. Trending was assessed by concordance and a 4-Quadrant error grid analysis. Error between pulse contour and thermodilution increased with longer calibration times. Limits of agreement were -1.85 to 1.66 L/min for 1 h maximum calibration time compared to -2.70 to 2.41 L/min for 24 h. Error grid analysis resulted in 74.2 % of points bounded by 20 % error limits of thermodilution measurements for 1 h calibration time compared to 65 % for 24 h. 4-Quadrant error grid analysis showed analysis method and thermodilution showed poor agreement to monitor changes in cardiac output.

  15. Finite Element Analysis of the Effect of Proximal Contour of Class II Composite Restorations on Stress Distribution

    Directory of Open Access Journals (Sweden)

    Mohammad Javad Moghaddas

    2013-01-01

    Full Text Available Introduction: The aim of this study was to evaluate the effect of proximal contour of class II composite restorations placed with straight or contoured matrix band using composite resins with different modulus of elasticity on stress distribution by finite element method. Methods: In order to evaluate the stress distribution of class II composite restorations using finite element method, upper right first molar and second premolar were modeled. Proximal boxes were designed and restored with universal Z250 and packable P60 composite resins (3M ESPE using two matrix systems: flat Tofflemire matrix and precurved sectional matrix. Finally models were evaluated under loads of 200 and 400 Newton at 90 degrees angle and the results were graphically illustrated in the form of Von Misses stresses. Results: In general the stress obtained under 400 Newton load was significantly greater than the stress of models under 200 Newton load. Von Misses stress distribution pattern of two different Z250 and P60 composites were very similar in all modes of loading and proximal contour. In all analyzed models there was a significant difference between models restored with Tofflemire matrix with flat contour and models restored with sectional matrix with curved contour. This difference was greater in first molar than second premolar. Conclusion: Use of a contoured matrix band results in less stress in class II composite resin restorations.

  16. Finite Element Analysis of the Effect of Proximal Contour of Class II Composite Restorations on Stress Distribution

    Directory of Open Access Journals (Sweden)

    Hossein Abachizadeh

    2012-09-01

    Full Text Available Introduction: The aim of this study was to evaluate the effect of proximal contour of class II composite restorations placed with straight or contoured matrix band using composite resins with different modulus of elasticity on stress distribution by finite element method. Methods: In order to evaluate the stress distribution of class II composite restorations using finite element method, upper right first molar and second premolar were modeled. Proximal boxes were designed and restored with universal Z250 and packable P60 composite resins (3M ESPE using two matrix systems: flat Tofflemire matrix and precurved sectional matrix. Finally models were evaluated under loads of 200 and 400 Newton at 90 degrees angle and the results were graphically illustrated in the form of Von Misses stresses. Results: In general the stress obtained under 400 Newton load was significantly greater than the stress of models under 200 Newton load. Von Misses stress distribution pattern of two different Z250 and P60 composites were very similar in all modes of loading and proximal contour. In all analyzed models there was a significant difference between models restored with Tofflemire matrix with flat contour and models restored with sectional matrix with curved contour. This difference was greater in first molar than second premolar. Conclusion: Use of a contoured matrix band results in less stress in class II composite resin restorations.

  17. A shallow landslide analysis method consisting of contour line based method and slope stability model with critical slip surface

    Science.gov (United States)

    Tsutsumi, D.

    2015-12-01

    To mitigate sediment related disaster triggered by rainfall event, it is necessary to predict a landslide occurrence and subsequent debris flow behavior. Many landslide analysis method have been developed and proposed by numerous researchers for several decades. Among them, distributed slope stability models simulating temporal and spatial instability of local slopes are more essential for early warning or evacuation in area of lower part of hill-slopes. In the present study, a distributed, physically based landslide analysis method consisting of contour line-based method that subdivide a watershed area into stream tubes, and a slope stability analysis in which critical slip surface is searched to identify location and shape of the most instable slip surface in each stream tube, is developed. A target watershed area is divided into stream tubes using GIS technique, grand water flow for each stream tubes during a rainfall event is analyzed by a kinematic wave model, and slope stability for each stream tube is calculated by a simplified Janbu method searching for a critical slip surface using a dynamic programming method. Comparing to previous methods that assume infinite slope for slope stability analysis, the proposed method has advantage simulating landslides more accurately in spatially and temporally, and estimating amount of collapsed slope mass, that can be delivered to a debris flow simulation model as a input data. We applied this method to a small watershed in the Izu Oshima, Tokyo, Japan, where shallow and wide landslides triggered by heavy rainfall and subsequent debris flows attacked Oshima Town, in 2013. Figure shows the temporal and spatial change of simulated grand water level and landslides distribution. The simulated landslides are correspond to the uppermost part of actual landslide area, and the timing of the occurrence of landslides agree well with the actual landslides.

  18. Cavity Ringdown Absorption Spectrum of the T_1(n,π*) ← S_0 Transition of Acrolein: Analysis of the 0^0_0 Band Rotational Contour

    Science.gov (United States)

    Hlavacek, Nikolaus C.; McAnally, Michael O.; Drucker, Stephen

    2012-06-01

    Acrolein (propenal, CH_2=CH---CH=O) is the simplest conjugated enal molecule and serves as a prototype for investigating the photochemical properties of larger enals and enones. Acrolein has a coplanar arrangement of heavy atoms in its ground electronic state. Much of the photochemistry is mediated by the T_1(π,π*) state, which has a CH_2--twisted equilibrium structure. In solution, the T_1(π,π*) state is typically accessed via intersystem crossing from an intially prepared planar S_1(n,π*) state. An intermediate in this photophysical transformation is the lowest ^3 (n,π*) state, a planar species with adiabatic excitation energy below S_1 and above T_1(π,π*). The present work focuses on this ^3 (n,π*) intermediate state; it is designated T_1(n,π*) as the lowest-energy triplet state of acrolein having a planar equilibrium structure. The T_1(n,π*) ← S_0 band system, with origin near 412 nm, was first recorded in the 1970s at medium (0.5 cm-1) resolution using a long-path absorption cell. Here we report the cavity ringdown spectrum of the 0^0_0 band, recorded using a pulsed dye laser with 0.1 cm-1 spectral bandwidth. The spectrum was measured under both bulk-gas (room-temperature) and jet-cooled conditions. The band contour in each spectrum was analyzed by using a computer program developed for simulating and fitting the rotational structure of singlet-triplet transitions. The assignment of several resolved sub-band heads in the room-temperature spectrum permitted approximate fitting of the inertial constants for the T_1(n,π*) state. The determined values (cm-1) are A=1.662, B=0.1485, C=0.1363. For the parameters A and (B+C)/2, estimated uncertainties of ± 0.003 cm-1 and ± 0.0004 cm-1, respectively, correspond to a range of values that produce qualitatively satisfactory global agreement with the observed room-temperature contour. The fitted inertial constants were used to simulate the rotational contour of the 0^0_0 band under jet-cooled conditions

  19. Experimental and numerical study of nanofluid in heat exchanger fitted by modified twisted tape: exergy analysis and ANN prediction model

    Science.gov (United States)

    Maddah, Heydar; Ghasemi, Nahid; Keyvani, Bahram; Cheraghali, Ramin

    2016-09-01

    Present study provides an experimental investigation of the exergetic efficiency due to the flow and heat transfer of nanofluids in different geometries and flow regimes of the double pipe heat exchangers. The experiments with different Geometrical Progression Ratio (GPR) of twists as the new modified twisted tapes and different nanofluid concentration were performed under similar operation condition. Pitch length of the proposed twisted tapes and consequently the twist ratios changed along the twists with respect to the Geometrical Progression Ratio (GPR) whether reducer (RGPR 1). Regarding the experimental data, utilization of RGPR twists together with nanofluids tends to increase exergetic efficiency. Since the Prediction of exergetic efficiency from experimental process is complex and time consuming, artificial neural networks for identification of the relationship, which may exist between the thermal and flow parameters and exergetic efficiency, have been utilized. The network input consists of five parameters (Re,Pr ,φ, Tr, GPR) that crucially dominate the heat transfer process. The results proved that the introduced ANN model is reliable and capable in proposing a proper development plan for a heat exchanger and/or to determine the optimal plan of operation for heat transfer process.

  20. Generalised twisted partition functions

    CERN Document Server

    Petkova, V B

    2001-01-01

    We consider the set of partition functions that result from the insertion of twist operators compatible with conformal invariance in a given 2D Conformal Field Theory (CFT). A consistency equation, which gives a classification of twists, is written and solved in particular cases. This generalises old results on twisted torus boundary conditions, gives a physical interpretation of Ocneanu's algebraic construction, and might offer a new route to the study of properties of CFT.

  1. Wire harness twisting aid

    Science.gov (United States)

    Casey, E. J.; Commadore, C. C.; Ingles, M. E.

    1980-01-01

    Long wire bundles twist into uniform spiral harnesses with help of simple apparatus. Wires pass through spacers and through hand-held tool with hole for each wire. Ends are attached to low speed bench motor. As motor turns, operator moves hand tool away forming smooth twists in wires between motor and tool. Technique produces harnesses that generate less radio-frequency interference than do irregularly twisted cables.

  2. Analysis of Double Meridian Distance for a Closed Traverse Area towards Developing a Contour Map and Land Title

    Directory of Open Access Journals (Sweden)

    T. U. Ganiron Jr

    2014-07-01

    Full Text Available This research aimed to analyze double meridian distance for a closed traverse area in developing a land title for a propose gymnasium in Qassim University. Theodolite, leveling rod and steel tape plays an important role in measuring elevations, bearings and distances of the boundaries of a lot. Contour map is necessary to determine the traces of level surfaces of successive elevation. This will enable to identify the type of contour map and type of contour lines necessary for this project. Corel draw software is used to draw contour map and guide to interpret the significance of the variables. It is essential to check the error of closure for interior angles and for both latitude and departure before applying the Double Meridian Distance (DMD method to obtain the total area of the lot. Technical descriptions of the land such as distance, bearing, boundaries and area are necessary to visualize the shape & exact location of the land. Developing a land title will be obtained using the technical descriptions of the lot in preparation for the type of gymnasium necessary for Qassim University.

  3. Twisted network programming essentials

    CERN Document Server

    Fettig, Abe

    2005-01-01

    Twisted Network Programming Essentials from O'Reilly is a task-oriented look at this new open source, Python-based technology. The book begins with recommendations for various plug-ins and add-ons to enhance the basic package as installed. It then details Twisted's collection simple network protocols, and helper utilities. The book also includes projects that let you try out the Twisted framework for yourself. For example, you'll find examples of using Twisted to build web services applications using the REST architecture, using XML-RPC, and using SOAP. Written for developers who want to s

  4. Three-dimensional large eddy simulation and vorticity analysis of unsteady cavitating flow around a twisted hydrofoil

    Institute of Scientific and Technical Information of China (English)

    JI Bin; LUO Xian-wu; PENG Xiao-xing; WU Yu-lin

    2013-01-01

    Large Eddy Simulation (LES) was coupled with a mass transfer cavitation model to predict unsteady 3-D turbulent cavitating flows around a twisted hydrofoil.The wall-adapting local eddy-viscosity (WALE) model was used to give the Sub-Grid Scale (SGS) stress term.The predicted 3-D cavitation evolutions,including the cavity growth,break-off and collapse downstream,and the shedding cycle as well as its frequency agree fairly well with experimental results.The mechanism for the interactions between the cavitation and the vortices was discussed based on the analysis of the vorticity transport equation related to the vortex stretching,volumetric expansion/contraction and baroclinic torque terms along the hydrofoil mid-plane.The vortical flow analysis demonstrates that cavitation promotes the vortex production and the flow unsteadiness.In non-cavitation conditions,the streamline smoothly passes along the upper wall of the hydrofoil with no boundary layer separation and the boundary layer is thin and attached to the foil except at the trailing edge.With decreasing cavitation number,the present case has r =1.07,and the attached sheet cavitation becomes highly unsteady,with periodic growth and break-off to form the cavitation cloud.The expansion due to cavitation induces boundary layer separation and significantly increases the vorticity magnitude at the cavity interface.A detailed analysis using the vorticity transport equation shows that the cavitation accelerates the vortex stretching and dilatation and increases the baroclinic torque as the major source of vorticity generation.Examination of the flow field shows that the vortex dilatation and baroclinic torque terms increase in the cavitating case to the same magnitude as the vortex stretching term,while for the non-cavitating case these two terms are zero.

  5. Factorising the 3D Topologically Twisted Index

    CERN Document Server

    Cabo-Bizet, Alejandro

    2016-01-01

    In this work, path integral representations of the 3D topologically twisted index were studied. First, the index can be "factorised" into a couple of "blocks". The "blocks" being the partition functions of a type A semi-topological twisting of 3D N = 2 SYM placed on $\\mathbb{S}_2\\times (0, \\pi)$ and $\\mathbb{S}_2 \\times (\\pi, 2 \\pi)$ respectively. Second, as the path integral of the aforementioned theory over $\\mathbb{S}_2$ times $\\mathbb{S}_1$ with a point excluded. In this way we recover the sum over fluxes from integration over the real path and without sacrificing positive definiteness of the bosonic part of the localising action. We also reproduce the integration over the complex contour by using the localising term with positive definite bosonic part.

  6. Conformational analysis of cyclic sulphites. Twist conformations in 5-chloro 2-oxo 1,3,2-dioxathianes as evidenced by i.r., 1H NMR, dipole moments and X-ray diffraction data

    Science.gov (United States)

    Cazaux, Louis; Chassaing, Gérard; Maroni, Pierre

    The possible use of the SO stretching vibration as a conformational probe for the conformational analysis of six-membered cyclic sulphites has been shown on nine 5-chloro sulphites. Ananchomeric 2,5-axis twist forms have been demonstrated for five tert-butylated 5-chloro sulphites and conformational equilibria with 2,5- (and 1,4-) axis twist form participation for three dimethylated and one tert-butylated derivatives. Conformational ACl and ASO energies were deduced from chair forms and the weak free energy difference between chair and twist forms was confirmed.

  7. Maternal inheritance of twist and analysis of MAPK activation in embryos of the polychaete annelid Platynereis dumerilii.

    Directory of Open Access Journals (Sweden)

    Kathrin Pfeifer

    Full Text Available In this study, we aimed to identify molecular mechanisms involved in the specification of the 4d (mesentoblast lineage in Platynereis dumerilii. We employ RT-PCR and in situ hybridization against the Platynereis dumerilii twist homolog (Pdu-twist to reveal mesodermal specification within this lineage. We show that Pdu-twist mRNA is already maternally distributed. After fertilization, ooplasmatic segregation leads to relocation of Pdu-twist transcripts into the somatoblast (2d lineage and 4d, indicating that the maternal component of Pdu-twist might be an important prerequisite for further mesoderm specification but does not represent a defining characteristic of the mesentoblast. However, after the primordial germ cells have separated from the 4d lineage, zygotic transcription of Pdu-twist is exclusively observed in the myogenic progenitors, suggesting that mesodermal specification occurs after the 4d stage. Previous studies on spiral cleaving embryos revealed a spatio-temporal correlation between the 4d lineage and the activity of an embryonic organizer that is capable to induce the developmental fates of certain micromeres. This has raised the question if specification of the 4d lineage could be connected to the organizer activity. Therefore, we aimed to reveal the existence of such a proposed conserved organizer in Platynereis employing antibody staining against dpERK. In contrast to former observations in other spiralian embryos, activation of MAPK signaling during 2d and 4d formation cannot be detected which questions the existence of a conserved connection between organizer function and specification of the 4d lineage. However, our experiments unveil robust MAPK activation in the prospective nephroblasts as well as in the macromeres and some micromeres at the blastopore in gastrulating embryos. Inhibition of MAPK activation leads to larvae with a shortened body axis, defects in trunk muscle spreading and improper nervous system

  8. Overregularity in Oliver Twist

    Institute of Scientific and Technical Information of China (English)

    孔祥曼

    2015-01-01

    Oliver Twist is one of the earliest works of Charles Dickens. In this novel, the author uses many writing skills which impress the readers a lot. This paper gives a brief description of overregularity in Oliver Twist at the phonological and syntactical levels.

  9. Quantum mass correction for the twisted kink

    CERN Document Server

    Pawellek, Michael

    2008-01-01

    We present an analytic result for the 1-loop quantum mass correction in semiclassical quantization for the twisted \\phi^4 kink on S^1 without explicit knowledge of the fluctuation spectrum. For this purpose we use the contour integral representation of the spectral zeta function. By solving the Bethe ansatz equations for the n=2 Lame equation we obtain an analytic expression for the corresponding spectral discriminant. We discuss the renormalization issues of this model. An energetically preferred size for the compact space is finally obtained.

  10. Left Ventricular Speckle Tracking-Derived Cardiac Strain and Cardiac Twist Mechanics in Athletes: A Systematic Review and Meta-Analysis of Controlled Studies.

    Science.gov (United States)

    Beaumont, Alexander; Grace, Fergal; Richards, Joanna; Hough, John; Oxborough, David; Sculthorpe, Nicholas

    2017-06-01

    The athlete's heart is associated with physiological remodeling as a consequence of repetitive cardiac loading. The effect of exercise training on left ventricular (LV) cardiac strain and twist mechanics are equivocal, and no meta-analysis has been conducted to date. The objective of this systematic review and meta-analysis was to review the literature pertaining to the effect of different forms of athletic training on cardiac strain and twist mechanics and determine the influence of traditional and contemporary sporting classifications on cardiac strain and twist mechanics. We searched PubMed/MEDLINE, Web of Science, and ScienceDirect for controlled studies of aged-matched male participants aged 18-45 years that used two-dimensional (2D) speckle tracking with a defined athlete sporting discipline and a control group not engaged in training programs. Data were extracted independently by two reviewers. Random-effects meta-analyses, subgroup analyses, and meta-regressions were conducted. Our review included 13 studies with 945 participants (controls n = 355; athletes n = 590). Meta-analyses showed no athlete-control differences in LV strain or twist mechanics. However, moderator analyses showed greater LV twist in high-static low-dynamic athletes (d = -0.76, 95% confidence interval [CI] -1.32 to -0.20; p < 0.01) than in controls. Peak untwisting velocity (PUV) was greater in high-static low-dynamic athletes (d = -0.43, 95% CI -0.84 to -0.03; p < 0.05) but less than controls in high-static high-dynamic athletes (d = 0.79, 95% CI 0.002-1.58; p = 0.05). Elite endurance athletes had significantly less twist and apical rotation than controls (d = 0.68, 95% CI 0.19-1.16, p < 0.01; d = 0.64, 95% CI 0.27-1.00, p = 0.001, respectively) but no differences in basal rotation. Meta-regressions showed LV mass index was positively associated with global longitudinal (b = 0.01, 95% CI 0.002-0.02; p < 0.05), whereas systolic blood pressure was negatively

  11. Twisted equivariant matter

    CERN Document Server

    Freed, Daniel S

    2012-01-01

    We show how general principles of symmetry in quantum mechanics lead to twisted notions of a group representation. This framework generalizes both the classical 3-fold way of real/complex/quaternionic representations as well as a corresponding 10-fold way which has appeared in condensed matter and nuclear physics. We establish a foundation for discussing continuous families of quantum systems. Having done so, topological phases of quantum systems can be defined as deformation classes of continuous families of gapped Hamiltonians. For free particles there is an additional algebraic structure on the deformation classes leading naturally to notions of twisted equivariant K-theory. In systems with a lattice of translational symmetries we show that there is a canonical twisting of the equivariant K-theory of the Brillouin torus. We give precise mathematical definitions of two invariants of the topological phases which have played an important role in the study of topological insulators. Twisted equivariant K-theor...

  12. Twisted analytic torsion

    Institute of Scientific and Technical Information of China (English)

    MATHAI; Varghese

    2010-01-01

    We review the Reidemeister, Ray-Singer’s analytic torsion and the Cheeger-Mller theorem. We describe the analytic torsion of the de Rham complex twisted by a flux form introduced by the current authors and recall its properties. We define a new twisted analytic torsion for the complex of invariant differential forms on the total space of a principal circle bundle twisted by an invariant flux form. We show that when the dimension is even, such a torsion is invariant under certain deformation of the metric and the flux form. Under T-duality which exchanges the topology of the bundle and the flux form and the radius of the circular fiber with its inverse, the twisted torsion of invariant forms are inverse to each other for any dimension.

  13. Twisted Analytic Torsion

    CERN Document Server

    Mathai, Varghese

    2009-01-01

    We review the Reidemeister and Ray-Singer's analytic torsions and the Cheeger-M"uller theorem. We describe the analytic torsion of the de Rham complex twisted by a flux form introduced by the current authors and recall its properties. We define a new twisted analytic torsion for the complex of invariant differential forms on the total space of a principal circle bundle twisted by an invariant flux form. We show that when the dimension is even, such a torsion is invariant under certain deformation of the metric and the flux form. Under T-duality which exchanges the topology of the bundle and the flux form and the radius of the circular fiber with its inverse, the twisted torsions are inverse to each other for any dimensions.

  14. Finite element analysis of planar twist channel angular extrusion (PTCAE) as a novel severe plastic deformation method

    Energy Technology Data Exchange (ETDEWEB)

    Shokuhfar, Ali; Shamsborhan, Mahmoud [K. N. Toosi University of Technology, Tehran (Iran, Islamic Republic of)

    2014-05-15

    A new severe plastic deformation (SPD) method based on equal channel angular pressing (ECAP) is introduced for producing ultrafine grains in bulk alloys, entitled as 'Planar twist channel angular extrusion (PTCAE)'. In PTCAE method, there is additional angle, α, (plus φ and ψ angles in ECAP method) which represents angle associated with the lateral reversal arc of curvature in deformation zone. Three dimensional finite element method (FEM) simulations of both ECAP and PTCAE processes were performed in order to investigate the plastic deformation state of processed samples and, moreover, the effect of different die geometry (in terms of variation of planar twist angle) on plastic strain distribution and magnitude. Results revealed that PTCAE process related with ECAP process can impose higher strain values in different shear planes simultaneously in one deformation zone. Therefore, PTCAE can produce UFG or nanostructured materials better than ECAP method which has simpler design and significantly higher efficiency compared with other new SPD processes.

  15. Twisted radio waves and twisted thermodynamics.

    Science.gov (United States)

    Kish, Laszlo B; Nevels, Robert D

    2013-01-01

    We present and analyze a gedanken experiment and show that the assumption that an antenna operating at a single frequency can transmit more than two independent information channels to the far field violates the Second Law of Thermodynamics. Transmission of a large number of channels, each associated with an angular momenta 'twisted wave' mode, to the far field in free space is therefore not possible.

  16. Pulse contour analysis calibrated by Trans-pulmonar thermodilution (Picco Plus ® for the perioperative management of a caesarean section in a patient with severe cardiomyopathy

    Directory of Open Access Journals (Sweden)

    Nicolas Brogly

    2016-06-01

    Full Text Available ABSTRACT BACKGROUND: The delivery of cardiac patients is a challenge for the anaesthesiologist, to whom the welfare of both the mother and the foetus is a main issue. In case of caesarean section, advanced monitoring allows to optimize haemodynamic condition and to improve morbidity and mortality. OBJECTIVE: To describe the use of pulse contour analysis calibrated by Trans-pulmonar thermodilution (Picco Plus® for the perioperative management of a caesarean section in a patient with severe cardiomyopathy. CASE REPORT: We describe the case of a 28-year-old woman with a congenital heart disease who was submitted to a caesarean section under general anaesthesia for maternal pathology and foetal breech presentation. Intra- and post-operative management was optimized by advanced haemodynamic monitorization obtained by pulse contour wave analysis and thermodilution calibration (Picco Plus® monitor. The information about preload, myocardial contractility and postcharge was useful in guiding the fluid therapy and the use of vasoactive drugs. CONCLUSION: This case report illustrates the importance of advanced haemodynamic monitoring with an acceptably invasive device in obstetric patients with high cardiac risk. The increasing experience in advanced haemodynamic management will probably permit to decrease morbidity and mortality of obstetric patients in the future.

  17. Contouring variations and the role of atlas in non-small cell lung cancer radiation therapy: Analysis of a multi-institutional preclinical trial planning study.

    Science.gov (United States)

    Cui, Yunfeng; Chen, Wenzhou; Kong, Feng-Ming Spring; Olsen, Lindsey A; Beatty, Ronald E; Maxim, Peter G; Ritter, Timothy; Sohn, Jason W; Higgins, Jane; Galvin, James M; Xiao, Ying

    2015-01-01

    To quantify variations in target and normal structure contouring and evaluate dosimetric impact of these variations in non-small cell lung cancer (NSCLC) cases. To study whether providing an atlas can reduce potential variation. Three NSCLC cases were distributed sequentially to multiple institutions for contouring and radiation therapy planning. No segmentation atlas was provided for the first 2 cases (Case 1 and Case 2). Contours were collected from submitted plans and consensus contour sets were generated. The volume variation among institution contours and the deviation of them from consensus contours were analyzed. The dose-volume histograms for individual institution plans were recalculated using consensus contours to quantify the dosimetric changes. An atlas containing targets and critical structures was constructed and was made available when the third case (Case 3) was distributed for planning. The contouring variability in the submitted plans of Case 3 was compared with that in first 2 cases. Planning target volume (PTV) showed large variation among institutions. The PTV coverage in institutions' plans decreased dramatically when reevaluated using the consensus PTV contour. The PTV contouring consistency did not show improvement with atlas use in Case 3. For normal structures, lung contours presented very good agreement, while the brachial plexus showed the largest variation. The consistency of esophagus and heart contouring improved significantly (t test; P atlas improved the contour agreement for esophagus and heart, but not for the PTV in this study. Quality assurance of contouring is essential for a successful multi-institutional clinical trial. Copyright © 2015 American Society for Radiation Oncology. Published by Elsevier Inc. All rights reserved.

  18. Twisted derivations of Hopf algebras

    CERN Document Server

    Davydov, Alexei

    2012-01-01

    In the paper we introduce the notion of twisted derivation of a bialgebra. Twisted derivations appear as infinitesimal symmetries of the category of representations. More precisely they are infinitesimal versions of twisted automorphisms of bialgebras. Twisted derivations naturally form a Lie algebra (the tangent algebra of the group of twisted automorphisms). Moreover this Lie algebra fits into a crossed module (tangent to the crossed module of twisted automorphisms). Here we calculate this crossed module for universal enveloping algebras and for the Sweedler's Hopf algebra.

  19. Next-to-next-to-leading order QCD analysis of the revised CCFR data for $xF_3$ structure function and the higher twist contributions

    CERN Document Server

    Kataev, A L; Parente, G; Sidorov, A V

    1998-01-01

    We present the results of the next-to-next-to-leading order QCD analysis of the recently revised experimental data of the CCFR collaboration for the $xF_3$ structure function using the Jacobi polynomial expansion method. The effects of the higher twist contributions are included into the fits following the infrared renormalon motivated model. The special attention is paid to the checks of the predictive abilities of the infrared renormalon model and to the independent extraction of the $x$-shape of the twist-4 contributions to the $xF_3$ structure function in the process of the leading order, next-to-leading order and next-to-next-to-leading order fits of the revised CCFR data. We stress that at the next-to-next-to-leading order the results for We obtain the following result $\\alpha_s(M_Z)^{NNLO}=0.117 \\pm 0.002(stat) \\pm 0.005 (syst)\\pm 0.003 (theory)$. The comparison of the outcomes of our next-to-leading order and next-to-next-to-leading order analysis indicate that the theoretical QCD uncertainties were u...

  20. Visualization of Uncertain Contour Trees

    DEFF Research Database (Denmark)

    Kraus, Martin

    2010-01-01

    Contour trees can represent the topology of large volume data sets in a relatively compact, discrete data structure. However, the resulting trees often contain many thousands of nodes; thus, many graph drawing techniques fail to produce satisfactory results. Therefore, several visualization methods...... were proposed recently for the visualization of contour trees. Unfortunately, none of these techniques is able to handle uncertain contour trees although any uncertainty of the volume data inevitably results in partially uncertain contour trees. In this work, we visualize uncertain contour trees...... by combining the contour trees of two morphologically filtered versions of a volume data set, which represent the range of uncertainty. These two contour trees are combined and visualized within a single image such that a range of potential contour trees is represented by the resulting visualization. Thus...

  1. Expression of Twist Gene in Primary Liver Cancer

    Institute of Scientific and Technical Information of China (English)

    XU Jing; CHEN Xiaoping

    2007-01-01

    In order to investigate the possibility of overexpression of Twist in primary liver cancer (PLC), the Twist expression was detected by using immunohistochemical analysis and RT-PCR assay in 45 patients with PLC. Control tissues were obtained from 9 patients with liver hemangioma. It was found that in 36 (80.0%) out of 45 PLC patients, cancerous regions showed positive cytoplasm and nucleus staining for Twist with a diffuse pattern. In noncancerous adjacent areas and control liver tissues, the expression of Twist was 57.8% and 22.2% respectively. The results of RT-PCR assay re- vealed that the expression of Twist was stronger in the cancerous tissues than that in the noncancer- ous adjacent tissues. It was suggested that the expression of Twist was up-regulated in PLC, which play an important role in the progression of PLC.

  2. Twist decomposition of proton structure from BFKL and BK amplitudes

    CERN Document Server

    Motyka, Leszek

    2014-01-01

    An analysis of twist composition of Balitsky-Kovchegov (BK) amplitude is performed in the double logarithmic limit. In this limit the BK evolution of color dipole -- proton scattering is equivalent to BFKL evolution which follows from vanishing of the Bartels vertex in the collinear limit. We perform twist decomposition of the BFKL/BK amplitude for proton structure functions and find compact analytic expressions that provide accurate approximations for higher twist amplitudes. The BFKL/BK higher twist amplitudes are much smaller than those following from eikonal saturation models.

  3. QUANTITATIVE MEASUREMENT OF THE SIMILARITIES AND DIFFERENCES OF CLONES OF GRAPES USING CONTOURS OF LEAVES WITH THE USE OF ASC-ANALYSIS AND "EIDOS" SYSTEM

    Directory of Open Access Journals (Sweden)

    Lutsenko Y. V.

    2016-02-01

    Full Text Available The article discusses the application of automated system-cognitive analysis (ASC-analysis, its mathematical model is a system of information theory and implements, its software tools – intellectual system called "Eidos" for solving one of the important tasks of ampelography: to quantify the similarities and differences of different clones of grapes using contours of the leaves. To solve this task we perform the following steps: 1 digitization of scanned images of the leaves and creation their mathematical models; 2 formation mathematical models of specific leaves with the application of information theory; 3 modeling the generalized images of leaves of different clones on the basis of specific leaves (multiparameter typing; 4 verification of the model by identifying specific leaf images with generic clones, i.e., classes (system identification; 5 quantification of the similarities and differences of the clones, i.e. cluster-constructive analysis of generalized images of leaves of various clones. The specific shape of the contour of the leaf is regarded as noise information on the clone to which it relates, including information about the true shape of a leaf of this clone (clean signal and noise, which distort the real shape, due to the random influence of the environment. Software tools of ASA-analysis which is intellectual "Eidos" system provides the noise suppression and the detection of a signal about the true shape of a leaf of each clone on the basis of a number of noisy concrete examples of the leaves of this clone. This creates a single image of the shape of the leaf of each clone, independent of their specific implementations, i.e. "Eidos" of these images (in the sense of Plato - the prototype or archetype (in the Jungian sense of the images

  4. 扭曲管双壳程换热器的研究及性能分析%RESEARCH AND PERFORMANCE ANALYSIS OF THE DOUBLE SHELL TWISTED TUBE HEAT EXCHANGER

    Institute of Scientific and Technical Information of China (English)

    宋丹; 蹇江海; 张迎恺

    2012-01-01

    This paper introduces the difference between the special structure of the twisted tube heat exchanger and that of the common heat exchanger. It found out the advantages of the twisted tube heat exchanger over the common one. The paper makes an in-depth analysis on the comprehensive performance of the twisted tube heat exchanger and discusses various factors that may influence its performance. It focuses on the pressure drop within and without the tube and the heat transfer coefficient of the twisted tube heat exchanger. The paper also presents the prospects for further research of the twisted tube heat exchanger.%介绍了扭曲管换热器的特殊结构以及与普通换热器的区别,得出了扭曲管换热器相比于普通换热器的优点;深入分析了扭曲管换热器的综合性能,并对影响其综合性能的各种因素进行了讨论,重点讨论了扭曲管换热器管内及管外的压降和传热系数;对扭曲管换热器的进一步研究进行了展望.

  5. SpaceTwist

    DEFF Research Database (Denmark)

    Yiu, Man Lung; Jensen, Christian Søndergaard; Xuegang, Huang

    2008-01-01

    -based matching generally fall short in offering practical query accuracy guarantees. Our proposed framework, called SpaceTwist, rectifies these shortcomings for k nearest neighbor (kNN) queries. Starting with a location different from the user's actual location, nearest neighbors are retrieved incrementally...

  6. Reweighting twisted boundary conditions

    CERN Document Server

    Bussone, Andrea; Hansen, Martin; Pica, Claudio

    2015-01-01

    Imposing twisted boundary conditions on the fermionic fields is a procedure extensively used when evaluating, for example, form factors on the lattice. Twisting is usually performed for one flavour and only in the valence, and this causes a breaking of unitarity. In this work we explore the possibility of restoring unitarity through the reweighting method. We first study some properties of the approach at tree level and then we stochastically evaluate ratios of fermionic determinants for different boundary conditions in order to include them in the gauge averages, avoiding in this way the expensive generation of new configurations for each choice of the twisting angle, $\\theta$. As expected the effect of reweighting is negligible in the case of large volumes but it is important when the volumes are small and the twisting angles are large. In particular we find a measurable effect for the plaquette and the pion correlation function in the case of $\\theta=\\pi/2$ in a volume $16\\times 8^3$, and we observe a syst...

  7. The twisted Mellin transform

    OpenAIRE

    Wang, Zuoqin

    2007-01-01

    The "twisted Mellin transform" is a slightly modified version of the usual classical Mellin transform on $L^2(\\mathbb R)$. In this short note we investigate some of its basic properties. From the point of views of combinatorics one of its most important interesting properties is that it intertwines the differential operator, $df/dx$, with its finite difference analogue, $\

  8. Resonances and higher twist in polarized lepton-nucleon scattering

    CERN Document Server

    Edelmann, J; Kaiser, N; Weise, W

    2000-01-01

    We present a detailed analysis of resonance contributions in the context of higher twist effects in the moments of the proton spin structure function g_1. For each of these moments, it is found that there exists a characteristic Q^2 region in which (perturbative) higher twist corrections coexist with (non-perturbative) resonance contribution of comparable magnitude.

  9. Cardiac mechanics and ventricular twist by three-dimensional strain analysis in relation to B-type natriuretic peptide as a clinical prognosticator for heart failure patients.

    Directory of Open Access Journals (Sweden)

    Sheng-Nan Chang

    Full Text Available BACKGROUND: Three dimensional (3D echocardiography-derived measurements of myocardial deformation and twist have recently advanced as novel clinical tools. However, with the exception of left ventricular ejection fraction and mass quantifications in hypertension and heart failure populations, the prognostic value of such imaging techniques remains largely unexplored. METHODS: We studied 200 subjects (mean age: 60.2±16 years, 54% female, female n = 107 with known hypertension (n = 51, diastolic heart failure (n = 61, or systolic heart failure (n = 30, recruited from heart failure outpatient clinics. Fifty-eight healthy volunteers were used as a control group. All participants underwent 3D-based myocardial deformation and twist analysis (Artida, Toshiba Medical Systems, Tokyo, Japan. We further investigated associations between these measures and brain natriuretic peptide levels and clinical outcomes. RESULTS: The global 3D strain measurements of the healthy, hypertension, diastolic heart failure, and systolic heart failure groups were 28.03%, 24.43%, 19.70%, and 11.95%, respectively (all p<0.001. Global twist measurements were estimated to be 9.49°, 9.77°, 8.32°, and 4.56°, respectively. We observed significant differences regarding 3D-derived longitudinal, radial, and global 3D strains between the different disease categories (p<0.05, even when age, gender, BMI and heart rate were matched. In addition, 3D-derived longitudinal, circumferential, and 3D strains were all highly correlated with brain natriuretic peptide levels (p<0.001. At a mean 567.7 days follow-up (25th-75th IQR: 197-909 days, poorer 3D-derived longitudinal, radial, and global 3D strain measurements remained independently associated with a higher risk of cardiovascular related death or hospitalization due to heart failure, after adjusting for age, gender, and left ventricular ejection fraction (all p<0.05. CONCLUSIONS: 3D-based strain analysis may be a

  10. Probabilistic contour extraction based on shape prior model

    Institute of Scientific and Technical Information of China (English)

    FAN Xin; LIANG De-qun

    2005-01-01

    Statistical shape prior model is employed to construct the dynamics in probabilistic contour estimation.By applying principal component analysis,plausible shape samples are efficiently generated to predict contour samples.Based on the shape-dependent dynamics and probabilistic image model,a particle filter is used to estimate the contour with a specific shape.Compared with the deterministic approach with shape information,the proposed method is simple yet more effective in extracting contours from images with shape variations and occlusion.

  11. Unraveling cellulose microfibrils: a twisted tale.

    Science.gov (United States)

    Hadden, Jodi A; French, Alfred D; Woods, Robert J

    2013-10-01

    Molecular dynamics (MD) simulations of cellulose microfibrils are pertinent to the paper, textile, and biofuels industries for their unique capacity to characterize dynamic behavior and atomic-level interactions with solvent molecules and cellulase enzymes. While high-resolution crystallographic data have established a solid basis for computational analysis of cellulose, previous work has demonstrated a tendency for modeled microfibrils to diverge from the linear experimental structure and adopt a twisted conformation. Here, we investigate the dependence of this twisting behavior on computational approximations and establish the theoretical basis for its occurrence. We examine the role of solvent, the effect of nonbonded force field parameters [partial charges and van der Waals (vdW) contributions], and the use of explicitly modeled oxygen lone pairs in both the solute and solvent. Findings suggest that microfibril twisting is favored by vdW interactions, and counteracted by both intrachain hydrogen bonds and solvent effects at the microfibril surface.

  12. Twisted quantum doubles

    Directory of Open Access Journals (Sweden)

    Daijiro Fukuda

    2004-01-01

    Full Text Available Using diagrammatic pictures of tensor contractions, we consider a Hopf algebra (Aop⊗ℛλA** twisted by an element ℛλ∈A*⊗Aop corresponding to a Hopf algebra morphism λ:A→A. We show that this Hopf algebra is quasitriangular with the universal R-matrix coming from ℛλ when λ2=idA, generalizing the quantum double construction which corresponds to the case λ=idA.

  13. Image Demosaicking with Contour Stencils

    Directory of Open Access Journals (Sweden)

    Pascal Getreuer

    2012-03-01

    Full Text Available Demosaicking (or demosaicing is the problem of interpolating full color information on an image where only one color component is known at each pixel. Most demosaicking methods involve some kind of estimation of the underlying image structure, for example, choosing adaptively between interpolating in the horizontal or vertical direction. This article discusses the implementation details of the method introduced in Getreuer, “Color Demosaicing with Contour Stencils,” 2011. Mosaicked contour stencils first estimate the image contour orientations directly from the mosaicked data. The mosaicked contour stencils are then used to guide a simple demosaicking method based on graph regularization.

  14. Twist planet drive

    Science.gov (United States)

    Vranish, John M. (Inventor)

    1996-01-01

    A planetary gear system includes a sun gear coupled to an annular ring gear through a plurality of twist-planet gears, a speeder gear, and a ground structure having an internal ring gear. Each planet gear includes a solid gear having a first half portion in the form of a spur gear which includes vertical gear teeth and a second half portion in the form of a spur gear which includes helical gear teeth that are offset from the vertical gear teeth and which contact helical gear teeth on the speeder gear and helical gear teeth on the outer ring gear. One half of the twist planet gears are preloaded downward, while the other half are preloaded upwards, each one alternating with the other so that each one twists in a motion opposite to its neighbor when rotated until each planet gear seats against the sun gear, the outer ring gear, the speeder gear, and the inner ring gear. The resulting configuration is an improved stiff anti-backlash gear system.

  15. Gluon polarization and higher twist effects

    CERN Document Server

    Leader, Elliot; Stamenov, Dimiter

    2008-01-01

    We examine the influence of the recent CLAS and COMPASS experiments on our understanding of higher twist (HT) effects and the gluon polarization, and show how EIC could discriminate between negative and positive gluon polarizations. We comment on the issue of HT and the recent DSSV analysis.

  16. Demonstration of characteristic skin surface contours of extramammary Paget's disease and parapsoriasis en plaque by image analysis of negative impression replicas.

    Science.gov (United States)

    Kikuchi, Katsuko; Aiba, Setsuya; O'Goshi, Ken-ichiro; Yanai, Motohiro; Takahashi, Motoji; Kasai, Hidefumi; Tagami, Hachiro

    2002-10-01

    The surface contours of lesional skin of certain skin diseases, such as parapsoriasis en plaque (PEP) and extramammary Paget's disease (EMPD), in which there is a massive infiltration by non-epidermal cells, looks somewhat different from that of the adjacent normal skin, needless to state that they are apparently different from that of ordinary chronic inflammatory dermatoses where we found acanthotic epidermis accompanied by hyperkeratosis. We attempted to objectively characterize these unique skin surface changes qualitatively and quantitatively using non-invasive methods. Negative impression replicas were taken from the lesional skin of patients with EMPD or PEP as well as from the adjacent uninvolved skin. The findings were confirmed histologically. The replicas were examined by using computerized image analysis. Several parameters were analyzed that correlate with the changes in the anisotropy of the skin furrows (VC1), average skin roughness (KSD), average length of skin furrows (LEN), and number of skin furrows (NUM). There were significant decreases in KSD and NUM in EMPD, indicating a smoother skin surface in the lesional skin than in the adjacent normal skin. In contrast, the PEP lesion had an increase in VC1 and LEN and a decrease in NUM, which suggests larger skin ridges in the lesional skin than in the uninvolved skin. Thus the unique skin surface of the cutaneous disorders accompanied by epidermal invasion by non-epidermal cells, such as EMPD and PEP, was characterized both qualitatively and quantitatively using computerized image analysis of negative impression replicas.

  17. The Gravitational Field of a Twisted Skyrmion

    CERN Document Server

    Hadi, Miftachul; Husein, Andri

    2015-01-01

    We study nonlinear sigma model, especially Skyrme model without twist and Skyrme model with twist: twisted Skyrme model. Twist term, $mkz$, is indicated in vortex solution. We are interested to construct a space-time containing a string with Lagrangian plus a twist. To add gravity, we replace $\\eta^{\\mu\

  18. Twisted mass lattice QCD

    Energy Technology Data Exchange (ETDEWEB)

    Shindler, A. [Deutsches Elektronen-Synchrotron (DESY), Zeuthen (Germany). John von Neumann-Inst. fuer Computing NIC

    2007-07-15

    I review the theoretical foundations, properties as well as the simulation results obtained so far of a variant of the Wilson lattice QCD formulation: Wilson twisted mass lattice QCD. Emphasis is put on the discretization errors and on the effects of these discretization errors on the phase structure for Wilson-like fermions in the chiral limit. The possibility to use in lattice simulations different lattice actions for sea and valence quarks to ease the renormalization patterns of phenomenologically relevant local operators, is also discussed. (orig.)

  19. Computational fluid dynamics analysis of a twisted airfoil shaped two-bladed H-Darrieus rotor made from fibreglass reinforced plastic (FRP

    Directory of Open Access Journals (Sweden)

    Rajat Gupta, Sukanta Roy, Agnimitra Biswas

    2010-11-01

    Full Text Available H-Darrieus rotor is a lift type device having two to three blades designed as airfoils. The blades are attached vertically to the central shaft through support arms. The support to vertical axis helps the rotor maintain its shape. In this paper, Computational Fluid Dynamics (CFD analysis of an airfoil shaped two-bladed H-Darrieus rotor using Fluent 6.2 software was performed. Based on the CFD results, a comparative study between experimental and computational works was carried out. The H-Darrieus rotor was 20cm in height, 5cm in chord and twisted with an angle of 30° at the trailing end. The blade material of rotor was Fiberglass Reinforced Plastic (FRP. The experiments were earlier conducted in a subsonic wind tunnel for various height-to-diameter (H/D ratios. A two dimensional computational modeling was done with the help of Gambit tool using unstructured grid. Realistic boundary conditions were provided for the model to have synchronization with the experimental conditions. Two dimensional steady-state segregated solver with absolute velocity formulation and cell based grid was considered, and a standard k-epsilon viscous model with standard wall functions was chosen. A first order upwind discretization scheme was adopted for pressure velocity coupling of the flow. The inlet velocities and rotor rotational speeds were taken from the experimental results. From the computational analysis, power coefficient (Cp and torque coefficient (Ct values at ten different H/D ratios namely 0.85, 1.0, 1.10, 1.33, 1.54, 1.72, 1.80, 1.92, 2.10 and 2.20 were calculated in order to predict the performances of the twisted H-rotor. The variations of Cp and Ct with tip speed ratios were analyzed and compared with the experimental results. The standard deviations of computational Cp and Ct from experimental Cp and Ct were obtained. From the computational analysis, the highest values of Cp and Ct were obtained at H/D ratios of 1.0 and 1.54 respectively. The

  20. Pre-cancer risk assessment in habitual smokers from DIC images of oral exfoliative cells using active contour and SVM analysis.

    Science.gov (United States)

    Dey, Susmita; Sarkar, Ripon; Chatterjee, Kabita; Datta, Pallab; Barui, Ananya; Maity, Santi P

    2017-02-09

    Habitual smokers are known to be at higher risk for developing oral cancer, which is increasing at an alarming rate globally. Conventionally, oral cancer is associated with high mortality rates, although recent reports show the improved survival outcomes by early diagnosis of disease. An effective prediction system which will enable to identify the probability of cancer development amongst the habitual smokers, is thus expected to benefit sizable number of populations. Present work describes a non-invasive, integrated method for early detection of cellular abnormalities based on analysis of different cyto-morphological features of exfoliative oral epithelial cells. Differential interference contrast (DIC) microscopy provides a potential optical tool as this mode provides a pseudo three dimensional (3-D) image with detailed morphological and textural features obtained from noninvasive, label free epithelial cells. For segmentation of DIC images, gradient vector flow snake model active contour process has been adopted. To evaluate cellular abnormalities amongst habitual smokers, the selected morphological and textural features of epithelial cells are compared with the non-smoker (-ve control group) group and clinically diagnosed pre-cancer patients (+ve control group) using support vector machine (SVM) classifier. Accuracy of the developed SVM based classification has been found to be 86% with 80% sensitivity and 89% specificity in classifying the features from the volunteers having smoking habit.

  1. Aeromechanical Evaluation of Smart-Twisting Active Rotor

    Science.gov (United States)

    Lim, Joon W.; Boyd, D. Douglas, Jr.; Hoffman, Frauke; van der Wall, Berend G.; Kim, Do-Hyung; Jung, Sung N.; You, Young H.; Tanabe, Yasutada; Bailly, Joelle; Lienard, Caroline; Delrieux, Yves

    2014-01-01

    An investigation of Smart-Twisting Active Rotor (STAR) was made to assess potential benefits of the current active twist rotor concept for performance improvement, vibration reduction, and noise alleviation. The STAR rotor is a 40% Mach-scaled, Bo105 rotor with an articulated flap-lag hinge at 3.5%R and no pre-cone. The 0-5 per rev active twist harmonic inputs were applied for various flight conditions including hover, descent, moderate to high speed level flights, and slowed rotor high advance ratio. For the analysis, the STAR partners used multiple codes including CAMRAD II, S4, HOST, rFlow3D, elsA, and their associated software. At the high thrust level in hover, the 0 per rev active twist with 80% amplitude increased figure of merit (FM) by 0.01-0.02 relative to the baseline. In descent, the largest BVI noise reduction was on the order of 2 to 5 dB at the 3 per rev active twist. In the high speed case (mu = 0.35), the 2 per rev actuation was found to be the most effective in achieving a power reduction as well as a vibration reduction. At the 2 per rev active twist, total power was reduced by 0.65% at the 60 deg active twist phase, and vibration was reduced by 47.6% at the 45 deg active twist phase. The use of the 2 per rev active twist appears effective for vibration reduction. In the high advance ratio case (mu = 0.70), the 0 per rev actuation appeared to have negligible impact on performance improvement. In summary, computational simulations successfully demonstrated that the current active twist concept provided a significant reduction of the maximum BVI noise in descent, a significant reduction of the vibration in the high speed case, a small improvement on rotor performance in hover, and a negligible impact on rotor performance in forward flight.

  2. Green functions and twist correlators for $N$ branes at angles

    CERN Document Server

    Pesando, Igor

    2012-01-01

    We compute the Green functions and correlator functions for N twist fields for branes at angles on T^2 and we show that there are N-2 different configurations labeled by an integer M which is roughly associated with the number of obtuse angles of the configuration. In order to perform this computation we use a SL(2,R) invariant formulation and geometric constraints instead of Pochammer contours. In particular the M=1 or M=N-1 amplitude can be expressed without using transcendental functions. We determine the amplitudes normalization from N -> N-1 reduction without using the factorization into the untwisted sector. Both the amplitudes normalization and the OPE of two twist fields are unique (up to one constant) when the \\epsilon 1-\\epsilon symmetry is imposed. For consistency we find also an infinite number of relations among Lauricella hypergeometric functions.

  3. Twisted Ribbons: Theory, Experiment and Applications

    Science.gov (United States)

    Chopin, Julien; Davidovitch, Benjamin; Silva, Flavio A.; Toledo Filho, Romildo D.; Kudrolli, Arshad

    2014-03-01

    We investigate, experimentally and theoretically, the buckling and wrinkling instabilities of a pre-stretched ribbon upon twisting and propose strategies for the fabrication of structured yarns. Our experiment consists in a thin elastic sheet in the form of a ribbon which is initially stretched by a fixed load and then subjected to a twist by rotating the ends through a prescribed angle. We show that a wide variety of shapes and instabilities can be obtained by simply varying the applied twist and tension. The observed structures which include helicoids with and without longitudinal and transverse wrinkles, and spontaneous creases, can be organized in a phase diagram with the tension and twist angle as control parameters [J. Chopin and A. Kudrolli, PRL (2013)]. Using a far-from-threshold analysis and a slender body approximation, we provide a comprehensive understanding of the longitudinal and transverse instabilities and show that several regimes emerge depending on subtle combinations of loading and geometrical parameters. Further, we show that the wrinkling instabilities can be manipulated to fabricate structured yarns which may be used to encapsulate amorphous materials or serve as efficient reinforcements for cement-based composites. COPPETEC / CNPq - Science Without Border Program

  4. Tensor-SIFT based Earth Mover's Distance for Contour Tracking

    CERN Document Server

    Li, Peihua

    2010-01-01

    Contour tracking in adverse environments is a challenging problem due to cluttered background, illumination variation, occlusion, and noise, among others. This paper presents a robust contour tracking method by contributing to some of the key issues involved, including (a) a region functional formulation and its optimization; (b) design of a robust and effective feature; and (c) development of an integrated tracking algorithm. First, we formulate a region functional based on robust Earth Mover's distance (EMD) with kernel density for distribution modeling, and propose a two-phase method for its optimization. In the first phase, letting the candidate contour be fixed, we express EMD as the transportation problem and solve it by the simplex algorithm. Next, using the theory of shape derivative, we make a perturbation analysis of the contour around the best solution to the transportation problem. This leads to a partial differential equation (PDE) that governs the contour evolution. Second, we design a novel and...

  5. Contours - MO 2012 Greene County 5ft Contours (SHP)

    Data.gov (United States)

    NSGIC State | GIS Inventory — 5ft cartographic contour file for Greene County, Missouri. This file was created using the elevation data from the 2011 LiDAR flight. It includes indexes for 10, 25,...

  6. Contours - MO 2012 Greene County 5ft Contours (SHP)

    Data.gov (United States)

    NSGIC GIS Inventory (aka Ramona) — 5ft cartographic contour file for Greene County, Missouri. This file was created using the elevation data from the 2011 LiDAR flight. It includes indexes for 10, 25,...

  7. Contours - MO 2012 Greene County NW 1ft Contours (SHP)

    Data.gov (United States)

    NSGIC GIS Inventory (aka Ramona) — 1ft contour file for the northwest portion of Greene County, Missouri. This file was created using the USGS corrected elevation data from the 2011 LiDAR flight. It...

  8. Contours - MO 2012 Greene County SE 1ft Contours (SHP)

    Data.gov (United States)

    NSGIC GIS Inventory (aka Ramona) — 1ft contour file for the southeast portion of Greene County, Missouri. This file was created using the USGS corrected elevation data from the 2011 LiDAR flight. It...

  9. Contours - MO 2012 Greene County SW 1ft Contours (SHP)

    Data.gov (United States)

    NSGIC GIS Inventory (aka Ramona) — 1ft contour file for the southwest portion of Greene County, Missouri. This file was created using the USGS corrected elevation data from the 2011 LiDAR flight. It...

  10. Contours - MO 2012 Greene County NE 1ft Contours (SHP)

    Data.gov (United States)

    NSGIC GIS Inventory (aka Ramona) — 1ft contour file for the northeast portion of Greene County, Missouri. This file was created using the USGS corrected elevation data from the 2011 LiDAR flight. It...

  11. Twisting formula of epsilon factors

    Indian Academy of Sciences (India)

    SAZZAD ALI BISWAS

    2017-09-01

    For characters of a non-Archimedean local field we have explicit formula for epsilon factors. But in general, we do not have any generalized twisting formula of epsilon factors. In this paper, we give a generalized twisting formula of epsilon factorsvia local Jacobi sums.

  12. Twisted supergravity and its quantization

    CERN Document Server

    Costello, Kevin

    2016-01-01

    Twisted supergravity is supergravity in a background where the bosonic ghost field takes a non-zero value. This is the supergravity counterpart of the familiar concept of twisting supersymmetric field theories. In this paper, we give conjectural descriptions of type IIA and IIB supergravity in $10$ dimensions. Our conjectural descriptions are in terms of the closed-string field theories associated to certain topological string theories, and we conjecture that these topological string theories are twists of the physical string theories. For type IIB, the results of arXiv:1505.6703 show that our candidate twisted supergravity theory admits a unique quantization in perturbation theory. This is despite the fact that the theories, like the original physical theories, are non-renormalizable. Although we do not prove our conjectures, we amass considerable evidence. We find that our candidates for the twisted supergravity theories contain the residual supersymmetry one would expect. We also prove (using heavily a res...

  13. The Effect of Local Orientation Change on the Detection of Contours Defined by Constant Curvature: Psychophysics and Image Statistics

    Science.gov (United States)

    Khuu, Sieu K.; Cham, Joey; Hayes, Anthony

    2017-01-01

    In the present study, we investigated the detection of contours defined by constant curvature and the statistics of curved contours in natural scenes. In Experiment 1, we examined the degree to which human sensitivity to contours is affected by changing the curvature angle and disrupting contour curvature continuity by varying the orientation of end elements. We find that (1) changing the angle of contour curvature decreased detection performance, while (2) end elements oriented in the direction (i.e., clockwise) of curvature facilitated contour detection regardless of the curvature angle of the contour. In Experiment 2 we further established that the relative effect of end—element orientation on contour detection was not only dependent on their orientation (collinear or cocircular), but also their spatial separation from the contour, and whether the contour shape was curved or not (i.e., C-shaped or S-shaped). Increasing the spatial separation of end-elements reduced contour detection performance regardless of their orientation or the contour shape. However, at small separations, cocircular end-elements facilitated the detection of C-shaped contours, but not S-shaped contours. The opposite result was observed for collinear end-elements, which improved the detection of S- shaped, but not C-shaped contours. These dissociative results confirmed that the visual system specifically codes contour curvature, but the association of contour elements occurs locally. Finally, we undertook an analysis of natural images that mapped contours with a constant angular change and determined the frequency of occurrence of end elements with different orientations. Analogous to our behavioral data, this image analysis revealed that the mapped end elements of constantly curved contours are likely to be oriented clockwise to the angle of curvature. Our findings indicate that the visual system is selectively sensitive to contours defined by constant curvature and that this might

  14. Variations in target volume definition for postoperative radiotherapy in stage III non-small-cell lung cancer: analysis of an international contouring study.

    Science.gov (United States)

    Spoelstra, Femke O B; Senan, Suresh; Le Péchoux, Cecile; Ishikura, Satoshi; Casas, Francesc; Ball, David; Price, Allan; De Ruysscher, Dirk; van Sörnsen de Koste, John R

    2010-03-15

    Postoperative radiotherapy (PORT) in patients with completely resected non-small-cell lung cancer with mediastinal involvement is controversial because of the failure of earlier trials to demonstrate a survival benefit. Improved techniques may reduce toxicity, but the treatment fields used in routine practice have not been well studied. We studied routine target volumes used by international experts and evaluated the impact of a contouring protocol developed for a new prospective study, the Lung Adjuvant Radiotherapy Trial (Lung ART). Seventeen thoracic radiation oncologists were invited to contour their routine clinical target volumes (CTV) for 2 representative patients using a validated CD-ROM-based contouring program. Subsequently, the Lung ART study protocol was provided, and both cases were contoured again. Variations in target volumes and their dosimetric impact were analyzed. Routine CTVs were received for each case from 10 clinicians, whereas six provided both routine and protocol CTVs for each case. Routine CTVs varied up to threefold between clinicians, but use of the Lung ART protocol significantly decreased variations. Routine CTVs in a postlobectomy patient resulted in V(20) values ranging from 12.7% to 54.0%, and Lung ART protocol CTVs resulted in values of 20.6% to 29.2%. Similar results were seen for other toxicity parameters and in the postpneumectomy patient. With the exception of upper paratracheal nodes, protocol contouring improved coverage of the required nodal stations. Even among experts, significant interclinician variations are observed in PORT fields. Inasmuch as contouring variations can confound the interpretation of PORT results, mandatory quality assurance procedures have been incorporated into the current Lung ART study. Copyright 2010 Elsevier Inc. All rights reserved.

  15. Twisted bialgebroids versus bialgebroids from a Drinfeld twist

    Science.gov (United States)

    Borowiec, Andrzej; Pachoł, Anna

    2017-02-01

    Bialgebroids (respectively Hopf algebroids) are bialgebras (Hopf algebras) over noncommutative rings. Drinfeld twist techniques are particularly useful in the (deformation) quantization of Lie algebras as well as the underlying module algebras (=quantum spaces). A smash product construction combines both of them into the new algebra which, in fact, does not depend on the twist. However, we can turn it into a bialgebroid in a twist-dependent way. Alternatively, one can use Drinfeld twist techniques in a category of bialgebroids. We show that both the techniques indicated in the title—the twisting of a bialgebroid or constructing a bialgebroid from the twisted bialgebra—give rise to the same result in the case of a normalized cocycle twist. This can be useful for the better description of a quantum deformed phase space. We argue that within this bialgebroid framework one can justify the use of deformed coordinates (i.e. spacetime noncommutativity), which are frequently postulated in order to explain quantum gravity effects.

  16. Wavelet Representation of Contour Sets

    Energy Technology Data Exchange (ETDEWEB)

    Bertram, M; Laney, D E; Duchaineau, M A; Hansen, C D; Hamann, B; Joy, K I

    2001-07-19

    We present a new wavelet compression and multiresolution modeling approach for sets of contours (level sets). In contrast to previous wavelet schemes, our algorithm creates a parametrization of a scalar field induced by its contoum and compactly stores this parametrization rather than function values sampled on a regular grid. Our representation is based on hierarchical polygon meshes with subdivision connectivity whose vertices are transformed into wavelet coefficients. From this sparse set of coefficients, every set of contours can be efficiently reconstructed at multiple levels of resolution. When applying lossy compression, introducing high quantization errors, our method preserves contour topology, in contrast to compression methods applied to the corresponding field function. We provide numerical results for scalar fields defined on planar domains. Our approach generalizes to volumetric domains, time-varying contours, and level sets of vector fields.

  17. Visualizing Contour Trees within Histograms

    DEFF Research Database (Denmark)

    Kraus, Martin

    2010-01-01

    Many of the topological features of the isosurfaces of a scalar volume field can be compactly represented by its contour tree. Unfortunately, the contour trees of most real-world volume data sets are too complex to be visualized by dot-and-line diagrams. Therefore, we propose a new visualization...... that is suitable for large contour trees and efficiently conveys the topological structure of the most important isosurface components. This visualization is integrated into a histogram of the volume data; thus, it offers strictly more information than a traditional histogram. We present algorithms...... to automatically compute the graph layout and to calculate appropriate approximations of the contour tree and the surface area of the relevant isosurface components. The benefits of this new visualization are demonstrated with the help of several publicly available volume data sets....

  18. Contours--Offshore Monterey, California

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — This part of DS 781 presents bathymetric contours for several seafloor maps of the Monterey Canyon and Vicinity map area, California. The raster data file is...

  19. Contours--Offshore Aptos, California

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — This part of DS 781 presents data for the bathymetric contours for several seafloor maps of the Offshore of Aptos map area, California. The vector data file is...

  20. Contours--Offshore Aptos, California

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — This part of DS 781 presents data for the bathymetric contours for several seafloor maps of the Offshore of Aptos map area, California. The vector data file is...

  1. Contours--Offshore Monterey, California

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — This part of DS 781 presents bathymetric contours for several seafloor maps of the Monterey Canyon and Vicinity map area, California. The raster data file is...

  2. Leveraging the power of high performance computing for next generation sequencing data analysis: tricks and twists from a high throughput exome workflow.

    Science.gov (United States)

    Kawalia, Amit; Motameny, Susanne; Wonczak, Stephan; Thiele, Holger; Nieroda, Lech; Jabbari, Kamel; Borowski, Stefan; Sinha, Vishal; Gunia, Wilfried; Lang, Ulrich; Achter, Viktor; Nürnberg, Peter

    2015-01-01

    Next generation sequencing (NGS) has been a great success and is now a standard method of research in the life sciences. With this technology, dozens of whole genomes or hundreds of exomes can be sequenced in rather short time, producing huge amounts of data. Complex bioinformatics analyses are required to turn these data into scientific findings. In order to run these analyses fast, automated workflows implemented on high performance computers are state of the art. While providing sufficient compute power and storage to meet the NGS data challenge, high performance computing (HPC) systems require special care when utilized for high throughput processing. This is especially true if the HPC system is shared by different users. Here, stability, robustness and maintainability are as important for automated workflows as speed and throughput. To achieve all of these aims, dedicated solutions have to be developed. In this paper, we present the tricks and twists that we utilized in the implementation of our exome data processing workflow. It may serve as a guideline for other high throughput data analysis projects using a similar infrastructure. The code implementing our solutions is provided in the supporting information files.

  3. Leveraging the power of high performance computing for next generation sequencing data analysis: tricks and twists from a high throughput exome workflow.

    Directory of Open Access Journals (Sweden)

    Amit Kawalia

    Full Text Available Next generation sequencing (NGS has been a great success and is now a standard method of research in the life sciences. With this technology, dozens of whole genomes or hundreds of exomes can be sequenced in rather short time, producing huge amounts of data. Complex bioinformatics analyses are required to turn these data into scientific findings. In order to run these analyses fast, automated workflows implemented on high performance computers are state of the art. While providing sufficient compute power and storage to meet the NGS data challenge, high performance computing (HPC systems require special care when utilized for high throughput processing. This is especially true if the HPC system is shared by different users. Here, stability, robustness and maintainability are as important for automated workflows as speed and throughput. To achieve all of these aims, dedicated solutions have to be developed. In this paper, we present the tricks and twists that we utilized in the implementation of our exome data processing workflow. It may serve as a guideline for other high throughput data analysis projects using a similar infrastructure. The code implementing our solutions is provided in the supporting information files.

  4. Brief Analysis of Coincidences in Oliver Twist%试析《雾都孤儿》情节的巧合

    Institute of Scientific and Technical Information of China (English)

    闫晓茹

    2003-01-01

    英国著名批判现实主义作家狄更斯所著,其创作的特点之一是多处情节的巧合.从创作背景、发表形式、狄更斯的激进思想、独特的创作风格以及坚定的善恶有报的信念等四个方面作以全面、系统地分析,以此说明情节的巧合是这部小说的优势.%Oliver Twist by Dickens is characterized by a few coincidences especially happy encounters,about which some reviews are unfavorable.This paper,sharing quite opposite opinions to the unfavorable ones,proves coincidences have advantages by means of systematic analysis from the following four points: background of production and publication,Dickens'radical ideas,his unique artistic style as well as his firm belief "good is rewarded with good,and evil with evil."

  5. Optimality of human contour integration.

    Directory of Open Access Journals (Sweden)

    Udo A Ernst

    Full Text Available For processing and segmenting visual scenes, the brain is required to combine a multitude of features and sensory channels. It is neither known if these complex tasks involve optimal integration of information, nor according to which objectives computations might be performed. Here, we investigate if optimal inference can explain contour integration in human subjects. We performed experiments where observers detected contours of curvilinearly aligned edge configurations embedded into randomly oriented distractors. The key feature of our framework is to use a generative process for creating the contours, for which it is possible to derive a class of ideal detection models. This allowed us to compare human detection for contours with different statistical properties to the corresponding ideal detection models for the same stimuli. We then subjected the detection models to realistic constraints and required them to reproduce human decisions for every stimulus as well as possible. By independently varying the four model parameters, we identify a single detection model which quantitatively captures all correlations of human decision behaviour for more than 2000 stimuli from 42 contour ensembles with greatly varying statistical properties. This model reveals specific interactions between edges closely matching independent findings from physiology and psychophysics. These interactions imply a statistics of contours for which edge stimuli are indeed optimally integrated by the visual system, with the objective of inferring the presence of contours in cluttered scenes. The recurrent algorithm of our model makes testable predictions about the temporal dynamics of neuronal populations engaged in contour integration, and it suggests a strong directionality of the underlying functional anatomy.

  6. Disconnected diagrams with twisted-mass fermions

    CERN Document Server

    Abdel-Rehim, Abdou; Constantinou, Martha; Finkenrath, Jacob; Hadjiyiannakou, Kyriakos; Jansen, Karl; Kallidonis, Christos; Koutsou, Giannis; Avilés-Casco, Alejandro Vaquero

    2016-01-01

    The latest results from the Twisted-Mass collaboration on disconnected diagrams at the physical value of the pion mass are presented. In particular, we focus on the sigma terms, the axial charges and the momentum fraction, all of them for the nucleon. A detailed error analysis for each observable follows, showing the strengths and weaknesses of the one-end trick. Alternatives are discussed.

  7. Hybrid Parallel Contour Trees, Version 1.0

    Energy Technology Data Exchange (ETDEWEB)

    2017-01-03

    A common operation in scientific visualization is to compute and render a contour of a data set. Given a function of the form f : R^d -> R, a level set is defined as an inverse image f^-1(h) for an isovalue h, and a contour is a single connected component of a level set. The Reeb graph can then be defined to be the result of contracting each contour to a single point, and is well defined for Euclidean spaces or for general manifolds. For simple domains, the graph is guaranteed to be a tree, and is called the contour tree. Analysis can then be performed on the contour tree in order to identify isovalues of particular interest, based on various metrics, and render the corresponding contours, without having to know such isovalues a priori. This code is intended to be the first data-parallel algorithm for computing contour trees. Our implementation will use the portable data-parallel primitives provided by Nvidia’s Thrust library, allowing us to compile our same code for both GPUs and multi-core CPUs. Native OpenMP and purely serial versions of the code will likely also be included. It will also be extended to provide a hybrid data-parallel / distributed algorithm, allowing scaling beyond a single GPU or CPU.

  8. Twisted mass QCD at finite temperature

    Energy Technology Data Exchange (ETDEWEB)

    Ilgenfritz, E.M.; Mueller-Preussker, M.; Petschlies, M. [Humboldt-Universitaet, Berlin (Germany). Inst. fuer Physik; Jansen, K. [Deutsches Elektronen-Synchrotron (DESY), Zeuthen (Germany); Lombardo, M.P. [Istituto Nazionale di Fisica Nucleare, LNF, Frascati (Italy); Philipsen, O.; Zeidlewicz, L. [Muenster Univ. (Germany). Inst. fuer Theoretische Physik 1; Sternbeck, A. [Adelaide Univ. (Australia). CSSM School of Chemistry and Physics

    2007-10-15

    We discuss the use of Wilson fermions with twisted mass for simulations of QCD thermodynamics. As a prerequisite for a future analysis of the finite-temperature transition making use of automatic {partial_derivative} (a) improvement, we investigate the phase structure in the space spanned by the hopping parameter {kappa}, the coupling {beta}, and the twisted mass parameter {mu}. We present results for N{sub f}=2 degenerate quarks on a 16{sup 3} x 8 lattice, for which we investigate the possibility of an Aoki phase existing at strong coupling and vanishing {mu}, as well as of a thermal phase transition at moderate gauge couplings and non-vanishing {mu}. (orig.)

  9. Semantic Deviation in Oliver Twist

    Institute of Scientific and Technical Information of China (English)

    康艺凡

    2016-01-01

    Dickens, with his adeptness with language, applies semantic deviation skillfully in his realistic novel Oliver Twist. However, most studies and comments home and abroad on it mainly focus on such aspects as humanity, society, and characters. Therefore, this thesis will take a stylistic approach to Oliver Twist from the perspective of semantic deviation, which is achieved by the use of irony, hyperbole, and pun and analyze how the application of the technique makes the novel attractive.

  10. Null twisted geometries

    CERN Document Server

    Speziale, Simone

    2013-01-01

    We define and investigate a quantisation of null hypersurfaces in the context of loop quantum gravity on a fixed graph. The main tool we use is the parametrisation of the theory in terms of twistors, which has already proved useful in discussing the interpretation of spin networks as the quantization of twisted geometries. The classical formalism can be extended in a natural way to null hypersurfaces, with the Euclidean polyhedra replaced by null polyhedra with space-like faces, and SU(2) by the little group ISO(2). The main difference is that the simplicity constraints present in the formalims are all first class, and the symplectic reduction selects only the helicity subgroup of the little group. As a consequence, information on the shapes of the polyhedra is lost, and the result is a much simpler, abelian geometric picture. It can be described by an Euclidean singular structure on the 2-dimensional space-like surface defined by a foliation of space-time by null hypersurfaces. This geometric structure is na...

  11. Two-year survival analysis of twisted wire fixed retainer versus spiral wire and fiber-reinforced composite retainers: a preliminary explorative single-blind randomized clinical trial

    Science.gov (United States)

    Sobouti, Farhad; Rakhshan, Vahid; Saravi, Mahdi Gholamrezaei; Zamanian, Ali

    2016-01-01

    Objective Traditional retainers (both metal and fiber-reinforced composite [FRC]) have limitations, and a retainer made from more flexible ligature wires might be advantageous. We aimed to compare an experimental design with two traditional retainers. Methods In this prospective preliminary clinical trial, 150 post-treatment patients were enrolled and randomly divided into three groups of 50 patients each to receive mandibular canine-to-canine retainers made of FRC, flexible spiral wire (FSW), and twisted wire (TW). The patients were monitored monthly. The time at which the first signs of breakage/debonding were detected was recorded. The success rates of the retainers were compared using chi-squared, Kaplan-Meier, and Cox proportional-hazard regression analyses (α = 0.05). Results In total, 42 patients in the FRC group, 41 in the FSW group, and 45 in the TW group completed the study. The 2-year failure rates were 35.7% in the FRC group, 26.8% in the FSW group, and 17.8% in the TW group. These rates differed insignificantly (chi-squared p = 0.167). According to the Kaplan-Meier analysis, failure occurred at 19.95 months in the FRC group, 21.37 months in the FSW group, and 22.36 months in the TW group. The differences between the survival rates in the three groups were not significant (Cox regression p = 0.146). Conclusions Although the failure rate of the experimental retainer was two times lower than that of the FRC retainer, the difference was not statistically significant. The experimental TW retainer was successful, and larger studies are warranted to verify these results. PMID:27019825

  12. SENSITIVITY ANALYSIS BY ARTIFICIAL NEURAL NETWORK (ANN) OF VARIABLES THAT INFLUENCE THE DIAGONAL TWIST IN A PAPERBOARD INDUSTRIAL MACHINE

    OpenAIRE

    Guinter Neutzling Schneid; Rubens Chaves de Oliveira; Osvaldo Vieira

    2016-01-01

    The dimensional stability of the paper may change due to middle exchange moisture, releasing the latent stress acquired into the manufacturing process. One result of this tension release is the diagonal curl. This study aims to conduct a sensitivity analysis of the different input’s variables of an industrial paper machine, along with some laboratory measurements, in order to identify the importance in production of paperboard quality control and relate to the property of the paper called...

  13. Blade tip vortex measurements on actively twisted rotor blades

    Science.gov (United States)

    Bauknecht, André; Ewers, Benjamin; Schneider, Oliver; Raffel, Markus

    2017-05-01

    Active rotor control concepts, such as active twist actuation, have the potential to effectively reduce the noise and vibrations of helicopter rotors. The present study focuses on the experimental investigation of active twist for the reduction of blade-vortex interaction (BVI) effects on a model rotor. Results of a large-scale smart-twisting active rotor test under hover conditions are described. This test investigated the effects of individual blade twist control on the blade tip vortices. The rotor blades were actuated with peak torsion amplitudes of up to 2° and harmonic frequencies of 1-5/rev with different phase angles. Time-resolved stereoscopic particle image velocimetry was carried out to study the effects of active twist on the strength and trajectories of the tip vortices between ψ _ {v}= 3.6° and 45.7° of vortex age. The analysis of the vortex trajectories revealed that the 1/rev active twist actuation mainly caused a vertical deflection of the blade tip and the corresponding vortex trajectories of up to 1.3% of the rotor radius R above and -1%R below the unactuated condition. An actuation with frequencies of 2 and 3/rev significantly affected the shapes of the vortex trajectories and caused negative vertical displacements of the vortices relative to the unactuated case of up to 2%R within the first 35° of wake age. The 2 and 3/rev actuation also had the most significant effects on the vortex strength and altered the initial peak swirl velocity by up to -34 and +31% relative to the unactuated value. The present aerodynamic investigation reveals a high control authority of the active twist actuation on the strength and trajectories of the trailing blade tip vortices. The magnitude of the evoked changes indicates that the active twist actuation constitutes an effective measure for the mitigation of BVI-induced noise on helicopters.

  14. CFD study of a twisted blade H-Darrieus wind turbine

    Directory of Open Access Journals (Sweden)

    Rajat Gupta, Rituraj Gautam, Siddhartha Sankar Deka

    2014-01-01

    Full Text Available In this paper, a two-dimensional Computational Fluid Dynamics (CFD study of the performance of a H-Darrieus turbine with three twisted blade had been carried out. The chord length of each blade is 5cm and the blade height is considered to be same for all the rotors. A two dimensional (2D model of the turbine was designed in CATIA V5R19 software and a k-epsilon turbulence closure was adopted with the unstructured mesh generated around the rotor modeled in GAMBIT 2.3.16. The inlet velocities and the rotational speeds are taken from the experimental results and the CFD analysis was carried out in CFD Code-FLUENT 6.3.26. From the CFD analysis, power coefficient (Cp and torque coefficient (Ct at three different H/D ratios of 1.13, 1.31 and 1.55 respectively were calculated and compared with available experimental results. The computational analysis showed that the highest values of Cp (0.525 and Ct (0.95 were obtained at H/D ratios of 1.31 and 1.13 respectively. The deviation of computational Cp from experimental Cp was within ±3.08 % and that of computational Ct from experimental Ct was within ±1.106 %. A study of the flow behaviour around the rotor was also carried out using the pressure contours and velocity vectors plots. A maximum pressure drop is obtained for H/D ratio of 1.31 and a vortex reattachment near rear blade of rotor with H/D ratio of 1.31 was observed from the pressure contours and velocity vectors plots. The vortex attachment to the blade of the rotor enhances the lift coefficient of the rotor which helps in improving the power coefficient of the rotor. The comparison between the computational results and previous experimental work is pretty encouraging.

  15. Role of left ventricular twist mechanics in cardiomyopathies, dance of the helices

    Institute of Scientific and Technical Information of China (English)

    Floris; Kauer; Marcel; Leonard; Geleijnse; Bastiaan; Martijn; van; Dalen

    2015-01-01

    Left ventricular twist is an essential part of left ventricular function. Nevertheless, knowledge is limited in "the cardiology community" as it comes to twist mechanics. Fortunately the development of speckle tracking echocardiography, allowing accurate, reproducible and rapid bedside assessment of left ventricular twist, has boosted the interest in this important mechanical aspect of left ventricular deformation. Although the fundamental physiological role of left ventricular twist is undisputable, the clinical relevance of assessment of left ventricular twist in cardiomyopathies still needs to be established. The fact remains; analysis of left ventricular twist mechanics has already provided substantial pathophysiological understanding on a comprehensive variety of cardiomyopathies. It has become clear that increased left ventricular twist in for example hypertrophic cardiomyopathy may be an early sign of subendocardial(microvascular) dysfunction. Furthermore, decreased left ventricular twist may be caused by left ventricular dilatation or an extensive myocardial scar. Finally, the detection of left ventricular rigid body rotation in noncompaction cardiomyopathy may provide an indispensible method to objectively confirm this difficult diagnosis. All this endorses the value of left ventricular twist in the field of cardiomyopathies and may further encourage the implementation of left ventricular twist parameters in the "diagnostic toolbox" for cardiomyopathies.

  16. Free-edge effects in laminates under extension, bending and twisting. II - Sublaminate/layer modeling and analysis

    Science.gov (United States)

    Yin, Wan-Lee

    1992-01-01

    The stress-function-based variational method of Yin (1991) is extended and modified into a combined layer/sublaminate approach applicable to a laminated strip composed of a large number of differently orientated, anisotropic elastic plies. Lekhnitskii's (1963) stress functions are introduced into two interior layers adjacent to a particular interface. The remaining layers are grouped into an upper sublaminate and a lower sublaminate. The stress functions are expanded in truncated power series of the thickness coordinate, and the differential equations governing the coefficient functions are derived by using the complementary virtual work principle. The layer/sublaminate approach limits the dimension of the eigenvalue problem to a fixed number irrespective of the number of layers in the sublaminate, so that reasonably accurate solutions of the interlaminar stresses can be computed with extreme ease. For symmetric, four-layer, angle-ply and cross-ply laminates, a comparison of the previous analysis results based on the pure layer model and new results based on two different layer/sublaminate models indicates reasonable over-all agreement in the interlaminar stresses and superior agreement in the total peeling and shearing force.

  17. Illusory contour formation survives crowding.

    Science.gov (United States)

    Lau, Jonathan Siu Fung; Cheung, Sing-Hang

    2012-06-12

    Flanked objects are difficult to identify using peripheral vision due to visual crowding, which limits conscious access to target identity. Nonetheless, certain types of visual information have been shown to survive crowding. Such resilience to crowding provides valuable information about the underlying neural mechanism of crowding. Here we ask whether illusory contour formation survives crowding of the inducers. We manipulated the presence of illusory contours through the (mis)alignment of the four inducers of a Kanizsa square. In the inducer-aligned condition, the observers judged the perceived shape (thin vs. fat) of the illusory Kanizsa square, manipulated by small rotations of the inducers. In the inducer-misaligned condition, three of the four inducers (all except the upper-left) were rotated 90°. The observers judged the orientation of the upper-left inducer. Crowding of the inducers worsened observers' performance significantly only in the inducer-misaligned condition. Our findings suggest that information for illusory contour formation survives crowding of the inducers. Crowding happens at a stage where the low-level featural information is integrated for inducer orientation discrimination, but not at a stage where the same information is used for illusory contour formation.

  18. Towards Stabilizing Parametric Active Contours

    DEFF Research Database (Denmark)

    Liu, Jinchao; Fan, Zhun; Olsen, Søren Ingvor;

    2014-01-01

    Numerical instability often occurs in evolving of parametric active contours. This is mainly due to the undesired change of parametrization during evolution. In this paper, we propose a new tangential diffusion term to compensate this undesired change. As a result, the parametrization will converge...

  19. Contour Detection by CORF Operator

    NARCIS (Netherlands)

    Azzopardi, George; Petkov, Nicolai

    2012-01-01

    We propose a contour operator, called CORF, inspired by the properties of simple cells in visual cortex. It combines, by a weighted geometric mean, the blurred responses of difference-of-Gaussian operators that model cells in the lateral geniculate nucleus (LGN). An operator that has gained

  20. Modal Properties and Stability of Bend-Twist Coupled Wind Turbine Blades

    DEFF Research Database (Denmark)

    Stäblein, Alexander R.; Hansen, Morten Hartvig; Verelst, David Robert

    2016-01-01

    Coupling between bending and twist has a significant influence on the aeroelastic response of wind turbine blades. The coupling can arise from the blade geometry (e.g. sweep, prebending or deflection under load) or from the anisotropic properties of the blade material. Bend-twist coupling can...... be utilised to reduce the fatigue loads of wind turbine blades. In this study the effect of material based coupling on the aeroelastic modal properties and stability limits of the DTU 10 MW Reference Wind Turbine are investigated. The modal properties are determined by means of eigenvalue analysis around...... for flapwise (flap-twist coupling) or edgewise (edge-twist coupling) bending. Edge-twist coupling can increase or decrease the damping of the edgewise mode relative to the reference blade, depending on the operational condition of the turbine. Edge-twist to feather coupling for edgewise deflection towards...

  1. Polarization twist in perovskite ferrielectrics.

    Science.gov (United States)

    Kitanaka, Yuuki; Hirano, Kiyotaka; Ogino, Motohiro; Noguchi, Yuji; Miyayama, Masaru; Moriyoshi, Chikako; Kuroiwa, Yoshihiro

    2016-09-02

    Because the functions of polar materials are governed primarily by their polarization response to external stimuli, the majority of studies have focused on controlling polar lattice distortions. In some perovskite oxides, polar distortions coexist with nonpolar tilts and rotations of oxygen octahedra. The interplay between nonpolar and polar instabilities appears to play a crucial role, raising the question of how to design materials by exploiting their coupling. Here, we introduce the concept of 'polarization twist', which offers enhanced control over piezoelectric responses in polar materials. Our experimental and theoretical studies provide direct evidence that a ferrielectric perovskite exhibits a large piezoelectric response because of extended polar distortion, accompanied by nonpolar octahedral rotations, as if twisted polarization relaxes under electric fields. The concept underlying the polarization twist opens new possibilities for developing alternative materials in bulk and thin-film forms.

  2. Gulf of Mexico Deepwater Bathymetry Contours

    Data.gov (United States)

    Bureau of Ocean Energy Management, Department of the Interior — Gulf of Mexico Depth Contours derived from NOAA's NGDC bathymetric grids and from BOEM's seismic grid compilation. Both NOAA and BOEM contours are shown in meters or...

  3. Design optimization for active twist rotor blades

    Science.gov (United States)

    Mok, Ji Won

    This dissertation introduces the process of optimizing active twist rotor blades in the presence of embedded anisotropic piezo-composite actuators. Optimum design of active twist blades is a complex task, since it involves a rich design space with tightly coupled design variables. The study presents the development of an optimization framework for active helicopter rotor blade cross-sectional design. This optimization framework allows for exploring a rich and highly nonlinear design space in order to optimize the active twist rotor blades. Different analytical components are combined in the framework: cross-sectional analysis (UM/VABS), an automated mesh generator, a beam solver (DYMORE), a three-dimensional local strain recovery module, and a gradient based optimizer within MATLAB. Through the mathematical optimization problem, the static twist actuation performance of a blade is maximized while satisfying a series of blade constraints. These constraints are associated with locations of the center of gravity and elastic axis, blade mass per unit span, fundamental rotating blade frequencies, and the blade strength based on local three-dimensional strain fields under worst loading conditions. Through pre-processing, limitations of the proposed process have been studied. When limitations were detected, resolution strategies were proposed. These include mesh overlapping, element distortion, trailing edge tab modeling, electrode modeling and foam implementation of the mesh generator, and the initial point sensibility of the current optimization scheme. Examples demonstrate the effectiveness of this process. Optimization studies were performed on the NASA/Army/MIT ATR blade case. Even though that design was built and shown significant impact in vibration reduction, the proposed optimization process showed that the design could be improved significantly. The second example, based on a model scale of the AH-64D Apache blade, emphasized the capability of this framework to

  4. Higher-twist effects in the B → π transition form factor from QCD light-cone sum rules

    Energy Technology Data Exchange (ETDEWEB)

    Khodjamirian, Alexander; Rusov, Aleksey [Universitaet Siegen (Germany). Fakultaet IV, Department Physik, Theoretische Physik 1 Walter-Flex-Strasse 3 57068 Siegen

    2016-07-01

    I report on the progress in calculating new higher-twist corrections to the QCD light-cone sum rule for the B → π transition form factor. First, the expansion of the massive heavy-quark propagator in the external gluonic field near the light-cone was extended to include new terms containing the gluon-field strength derivatives. The resulting analytical expressions for the twist-5 and twist-6 contributions to the correlation function were obtained in a factorized approximation, expressed via the product of the quark-condensate density and the lower-twist pion distribution amplitudes. The numerical analysis of new higher-twist effects is in progress.

  5. Parallel peak pruning for scalable SMP contour tree computation

    Energy Technology Data Exchange (ETDEWEB)

    Carr, Hamish A. [Univ. of Leeds (United Kingdom); Weber, Gunther H. [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Univ. of California, Davis, CA (United States); Sewell, Christopher M. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Ahrens, James P. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2017-03-09

    As data sets grow to exascale, automated data analysis and visualisation are increasingly important, to intermediate human understanding and to reduce demands on disk storage via in situ analysis. Trends in architecture of high performance computing systems necessitate analysis algorithms to make effective use of combinations of massively multicore and distributed systems. One of the principal analytic tools is the contour tree, which analyses relationships between contours to identify features of more than local importance. Unfortunately, the predominant algorithms for computing the contour tree are explicitly serial, and founded on serial metaphors, which has limited the scalability of this form of analysis. While there is some work on distributed contour tree computation, and separately on hybrid GPU-CPU computation, there is no efficient algorithm with strong formal guarantees on performance allied with fast practical performance. Here in this paper, we report the first shared SMP algorithm for fully parallel contour tree computation, withfor-mal guarantees of O(lgnlgt) parallel steps and O(n lgn) work, and implementations with up to 10x parallel speed up in OpenMP and up to 50x speed up in NVIDIA Thrust.

  6. From Inpainting to Active Contours

    DEFF Research Database (Denmark)

    Lauze, Francois Bernard; Nielsen, Mads

    2008-01-01

    image and a guess on the location of the object to be segmented via variational inpainting method. A numerical evaluation of this reconstruction provides a "disocclusion measure" and the correct foreground segmentation region is expected to maximize this measure. This formulation is in fact an optimal...... control problem, where controls are shapes/regions and states are the corresponding inpaintings. Optimization of the disocclusion measure leads formally to a coupled contour evolution equation, an inpainting equation (the state equation) as well as a linear PDE depending on the inpainting (the adjoint...... state equation). The contour evolution is implemented in the framework of level sets. Finally, the proposed method is validated on various examples. We focus among others in the segmentation of calcified plaques observed in radiographs from human lumbar aortic regions. Keywords  Segmentation - Inpainting...

  7. Drinfel'd basis of twisted Yangians

    CERN Document Server

    Belliard, Samuel

    2014-01-01

    We present a quantization of a Lie bi-ideal structure for twisted half-loop algebras of finite dimensional simple complex Lie algebras. We obtain Drinfel'd basis formalism and algebra closure relations of twisted Yangians for all symmetric pairs of simple Lie algebras and for simple twisted even half-loop Lie algebras. We also give an explicit form of twisted Yangians in Drinfel'd basis for the sl3 Lie algebra.

  8. Properly twisted groups and their algebras

    CERN Document Server

    Bales, John W

    2011-01-01

    A twist property is developed which imparts certain properties on the twisted group algebra. These include an involution * satisfying (xy)*=y*x* and an inner product satisfying = and =. Examples of twisted group algebras having this property are the Cayley-Dickson algebras and Clifford algebras.

  9. Higher twist effects in deeply virtual Compton scattering

    Energy Technology Data Exchange (ETDEWEB)

    Pirnay, Bjoern Michael

    2016-08-01

    In this work we explore the effects of higher twist power corrections on the deeply virtual Compton scattering process. The calculation of the helicity amplitudes for all possible polarization combinations is performed within the framework of QCD operator product expansion. As a result the known accuracy of the amplitudes is improved to include the (kinematic) twist-4 contributions. For the most part the analysis focuses on spin-1/2 targets, the answers for scalar targets conveniently emerge as a byproduct. We investigate the analytical structure of these corrections and prove consistency with QCD factorization. We give an estimation of the numerical impact of the sub-leading twist contributions for proton targets with the help of a phenomenological model for the nonperturbative proton generalized parton distributions. We compare different twist approximations and relate predictions for physical observables to experiments performed by the Hall A, CLAS, HERMES, H1 and ZEUS collaborations. The estimate also includes a numerical study for planned COMPASS-II runs. Throughout the analysis special emphasis is put on the convention dependence induced by finite twist truncation of scattering amplitudes.

  10. Extension-twist coupling optimization in composite rotor blades

    Science.gov (United States)

    Ozbay, Serkan

    2005-07-01

    For optimal rotor performance in a tiltrotor aircraft the difference in the inflow and the rotor speeds between the hover and cruise flight modes suggests different blade twist and chord distributions. The blade twist rates in current tiltrotor applications are defined based upon a compromise between the figure of merit in hover and propeller efficiency in airplane mode. However, when each operation mode is considered separately the optimum blade distributions are found to be considerably different. Passive blade twist control, which uses the inherent variation in centrifugal forces on a rotor blade to achieve optimum blade twist distributions in each flight mode through the use of extension-twist coupled composite rotor blades, has been considered for performance improvement of tiltrotor aircraft over the last two decades. The challenge for this concept is to achieve the desired twisting deformations in the rotor blade without altering the aeroelastic characteristics of the vehicle. A concept referred to as the sliding mass concept is proposed in this work in order to increase the twist change with rotor speed for a closed-cell composite rotor blade cross-section to practical levels for performance improvement in a tiltrotor aircraft. The concept is based on load path changes for the centrifugal forces by utilizing non-structural masses readily available on a conventional blade, such as the leading edge balancing mass. A multilevel optimization technique based on the simulated annealing method is applied to improve the performance of the XV15 tiltrotor aircraft. A cross-sectional analysis tool, VABS together with a multibody dynamics code, DYMORE are integrated into the optimization process. The optimization results revealed significant improvements in the power requirement in hover while preserving cruise efficiency. It is also shown that about 21% of the improvement is provided through the sliding mass concept pointing to the additional flexibility the concept

  11. Berry phase transition in twisted bilayer graphene

    Science.gov (United States)

    Rode, Johannes C.; Smirnov, Dmitri; Schmidt, Hennrik; Haug, Rolf J.

    2016-09-01

    The electronic dispersion of a graphene bilayer is highly dependent on rotational mismatch between layers and can be further manipulated by electrical gating. This allows for an unprecedented control over electronic properties and opens up the possibility of flexible band structure engineering. Here we present novel magnetotransport data in a twisted bilayer, crossing the energetic border between decoupled monolayers and coupled bilayer. In addition a transition in Berry phase between π and 2π is observed at intermediate magnetic fields. Analysis of Fermi velocities and gate induced charge carrier densities suggests an important role of strong layer asymmetry for the observed phenomena.

  12. "Oliver Twist": A Teacher's Guide.

    Science.gov (United States)

    Cashion, Carol; Fischer, Diana

    This teacher's guide for public television's 3-part adaptation of Charles Dickens's "Oliver Twist" provides information that will help enrich students' viewing of the series, whether or not they read the novel. The guide includes a wide range of discussion and activity ideas; there is also a series Web site and a list of Web resources.…

  13. Helically twisted photonic crystal fibres.

    Science.gov (United States)

    Russell, P St J; Beravat, R; Wong, G K L

    2017-02-28

    Recent theoretical and experimental work on helically twisted photonic crystal fibres (PCFs) is reviewed. Helical Bloch theory is introduced, including a new formalism based on the tight-binding approximation. It is used to explore and explain a variety of unusual effects that appear in a range of different twisted PCFs, including fibres with a single core and fibres with N cores arranged in a ring around the fibre axis. We discuss a new kind of birefringence that causes the propagation constants of left- and right-spinning optical vortices to be non-degenerate for the same order of orbital angular momentum (OAM). Topological effects, arising from the twisted periodic 'space', cause light to spiral around the fibre axis, with fascinating consequences, including the appearance of dips in the transmission spectrum and low loss guidance in coreless PCF. Discussing twisted fibres with a single off-axis core, we report that optical activity in a PCF is opposite in sign to that seen in a step-index fibre. Fabrication techniques are briefly described and emerging applications reviewed. The analytical results of helical Bloch theory are verified by an extensive series of 'numerical experiments' based on finite-element solutions of Maxwell's equations in a helicoidal frame.This article is part of the themed issue 'Optical orbital angular momentum'. © 2017 The Authors.

  14. Helically twisted photonic crystal fibres

    Science.gov (United States)

    Russell, P. St. J.; Beravat, R.; Wong, G. K. L.

    2017-02-01

    Recent theoretical and experimental work on helically twisted photonic crystal fibres (PCFs) is reviewed. Helical Bloch theory is introduced, including a new formalism based on the tight-binding approximation. It is used to explore and explain a variety of unusual effects that appear in a range of different twisted PCFs, including fibres with a single core and fibres with N cores arranged in a ring around the fibre axis. We discuss a new kind of birefringence that causes the propagation constants of left- and right-spinning optical vortices to be non-degenerate for the same order of orbital angular momentum (OAM). Topological effects, arising from the twisted periodic `space', cause light to spiral around the fibre axis, with fascinating consequences, including the appearance of dips in the transmission spectrum and low loss guidance in coreless PCF. Discussing twisted fibres with a single off-axis core, we report that optical activity in a PCF is opposite in sign to that seen in a step-index fibre. Fabrication techniques are briefly described and emerging applications reviewed. The analytical results of helical Bloch theory are verified by an extensive series of `numerical experiments' based on finite-element solutions of Maxwell's equations in a helicoidal frame. This article is part of the themed issue 'Optical orbital angular momentum'.

  15. Helically twisted photonic crystal fibres

    Science.gov (United States)

    Beravat, R.; Wong, G. K. L.

    2017-01-01

    Recent theoretical and experimental work on helically twisted photonic crystal fibres (PCFs) is reviewed. Helical Bloch theory is introduced, including a new formalism based on the tight-binding approximation. It is used to explore and explain a variety of unusual effects that appear in a range of different twisted PCFs, including fibres with a single core and fibres with N cores arranged in a ring around the fibre axis. We discuss a new kind of birefringence that causes the propagation constants of left- and right-spinning optical vortices to be non-degenerate for the same order of orbital angular momentum (OAM). Topological effects, arising from the twisted periodic ‘space’, cause light to spiral around the fibre axis, with fascinating consequences, including the appearance of dips in the transmission spectrum and low loss guidance in coreless PCF. Discussing twisted fibres with a single off-axis core, we report that optical activity in a PCF is opposite in sign to that seen in a step-index fibre. Fabrication techniques are briefly described and emerging applications reviewed. The analytical results of helical Bloch theory are verified by an extensive series of ‘numerical experiments’ based on finite-element solutions of Maxwell's equations in a helicoidal frame. This article is part of the themed issue ‘Optical orbital angular momentum’. PMID:28069771

  16. Twist-joints and double twist-joints in RNA structure.

    Science.gov (United States)

    Boutorine, Yury I; Steinberg, Sergey V

    2012-12-01

    Analysis of available RNA crystal structures has allowed us to identify a new family of RNA arrangements that we call double twist-joints, or DTJs. Each DTJ is composed of a double helix that contains two bulges incorporated into different strands and separated from each other by 2 or 3 bp. At each bulge, the double helix is over-twisted, while the unpaired nucleotides of both bulges form a complex network of stacking and hydrogen-bonding with nucleotides of helical regions. In total, we identified 14 DTJ cases, which can be combined in three groups based on common structural characteristics. One DTJ is found in a functional center of the ribosome, another DTJ mediates binding of the pre-tRNA to the RNase P, and two more DTJs form the sensing domains in the glycine riboswitch.

  17. Analysis of Contour Disposal Method for Large Scale Surveying%浅析大比例尺数字测图等高线的处理

    Institute of Scientific and Technical Information of China (English)

    董安龙

    2015-01-01

    There are two methods for computer contour drawing , namely self-producing and manual operation .As some mistakes and distortions appear from the former method , the later method come into favour .The paper introduces the manual drawing operation .%等高线的机助绘制方法有二种:自动生成法;手工绘制法。自动生成的等高线由于受野外采集的数据和已有资料的影响往往会出现错误、失真、不美观。为了避免错误、失真和不美观的等高线出现,得到令人满意的能够表达真实地貌的等高线,就要对等高线进行恰到好处的处理。

  18. 基于FLUENT的内插扭带波纹管内流场分析%Flow Field Analysis of Bellows with Twist Tape Inserts Using FLUENT

    Institute of Scientific and Technical Information of China (English)

    王晓静; 李文艳; 孙启蒙

    2016-01-01

    利用流体力学软件FLUENT对波纹管与扭带结合时的流场及传热进行了数值模拟,结合场协同原理考察了不同结构参数和操作参数对流动和传热的影响。结果表明:在入口雷诺数5000~60000,内插扭带波纹管由于扭带的螺旋导流作用,使壁面边界层减薄,在流动区域形成漩涡产生二次流,强化了对流传热过程;插入扭带后的波纹管内的流动仍具有周期性的特点,压降比普通的波纹管增加了2~3倍,且扭率较小时压降较高;场协同角在管子入口处较小,随流动的进行逐渐增大并趋于稳定;协同角随入口速度的增大呈递增趋势;有扭带的波纹管较光管协同角减小了约10%,较普通波纹管减小了约2%,场协同程度随扭率减小而增强。%The object of the study is using CFD software FLUENT to numerically analyze the flow and heat transfer characteristics of bellows with twisted tape inserts within a Reynolds number range of 5000-60000. The convective heat transfer enhancement with different structurals and operating parameters were also investigated by combining field synergy principle. The results show that the velocity boundary layer is thinner and vortexes appear in the vicinity of the twisted tape due to its spiral effect. The secondary flows in the flow regime contribute to the convective heat transfer performance. The periodic flow is also found in bellows with twisted tape inserts. However, its pressure drop is 2~3 times higher than ordinary bellows, and the pressure drop increases with the decrease of twist ratio. The average intersection angle is small at the entrance, and it increases with the development of flow and then becomes stable. The average intersection angle also increases with the increase of entrance velocity. Compared with smooth tubes and normal bellows, the average intersection angle of bellows with twisted tape inserts decreases by about 10% and 2%, respectively, and

  19. Grouping by proximity in haptic contour detection.

    Directory of Open Access Journals (Sweden)

    Krista E Overvliet

    Full Text Available We investigated the applicability of the Gestalt principle of perceptual grouping by proximity in the haptic modality. To do so, we investigated the influence of element proximity on haptic contour detection. In the course of four sessions ten participants performed a haptic contour detection task in which they freely explored a haptic random dot display that contained a contour in 50% of the trials. A contour was defined by a higher density of elements (raised dots, relative to the background surface. Proximity of the contour elements as well as the average proximity of background elements was systematically varied. We hypothesized that if proximity of contour elements influences haptic contour detection, detection will be more likely when contour elements are in closer proximity. This should be irrespective of the ratio with the proximity of the background elements. Results showed indeed that the closer the contour elements were, the higher the detection rates. Moreover, this was the case independent of the contour/background ratio. We conclude that the Gestalt law of proximity applies to haptic contour detection.

  20. Active Contour with A Tangential Component

    CERN Document Server

    Wang, Junyan

    2012-01-01

    Conventional edge-based active contours often require the normal component of an edge indicator function on the optimal contours to approximate zero, while the tangential component can still be significant. In real images, the full gradients of the edge indicator function along the object boundaries are often small. Hence, the curve evolution of edge-based active contours can terminate early before converging to the object boundaries with a careless contour initialization. We propose a novel Geodesic Snakes (GeoSnakes) active contour that requires the full gradients of the edge indicator to vanish at the optimal solution. Besides, the conventional curve evolution approach for minimizing active contour energy cannot fully solve the Euler-Lagrange (EL) equation of our GeoSnakes active contour, causing a Pseudo Stationary Phenomenon (PSP). To address the PSP problem, we propose an auxiliary curve evolution equation, named the equilibrium flow (EF) equation. Based on the EF and the conventional curve evolution, w...

  1. Research and analysis on structure of twisted-cube connected network%扭立方体连接网络结构的研究与分析

    Institute of Scientific and Technical Information of China (English)

    王新阳; 梁家荣

    2013-01-01

    Referring to the structure of the crossed cube(CQn)and the definition of pair-related, this paper analyzes the struc-ture character of the twisted-cube connected network(TNn), and proves that TNn is disconnected for n5 and the number of the disconnected nodes is half of nodes in the network. Besides, by analyzing the problems of the twisted-cube connected network, it obtains a new network structure:the twisted crossed cube(TCQn), proves that the network is all connected, and makes some preliminary studies on its basic network properties, such as the regularity, connectivity, fault tolerance, recursiveness, and so on, which indicates that the TCQn has the same excellent network properties as the CQn.%根据交叉立方体(CQn)的结构与关联对的概念,对扭立方体连接网络(TNn)的结构特性进行了分析,证明了当n5时,TNn是不连通的,并且不连通的结点数占整个网络结点数的一半。通过分析扭立方体连接网络的错误所在,提出了一种新型网络结构--扭交叉立方体(TCQn),证明了该网络结构是完全连通的,初步研究了其基本网络性质,如正则性,连通度,容错度,递归性等,表明TCQn具有与CQn同样优秀的网络性质。

  2. An automated workflow for patient-specific quality control of contour propagation

    Science.gov (United States)

    Beasley, William J.; McWilliam, Alan; Slevin, Nicholas J.; Mackay, Ranald I.; van Herk, Marcel

    2016-12-01

    Contour propagation is an essential component of adaptive radiotherapy, but current contour propagation algorithms are not yet sufficiently accurate to be used without manual supervision. Manual review of propagated contours is time-consuming, making routine implementation of real-time adaptive radiotherapy unrealistic. Automated methods of monitoring the performance of contour propagation algorithms are therefore required. We have developed an automated workflow for patient-specific quality control of contour propagation and validated it on a cohort of head and neck patients, on which parotids were outlined by two observers. Two types of error were simulated—mislabelling of contours and introducing noise in the scans before propagation. The ability of the workflow to correctly predict the occurrence of errors was tested, taking both sets of observer contours as ground truth, using receiver operator characteristic analysis. The area under the curve was 0.90 and 0.85 for the observers, indicating good ability to predict the occurrence of errors. This tool could potentially be used to identify propagated contours that are likely to be incorrect, acting as a flag for manual review of these contours. This would make contour propagation more efficient, facilitating the routine implementation of adaptive radiotherapy.

  3. An automated workflow for patient-specific quality control of contour propagation.

    Science.gov (United States)

    Beasley, William J; McWilliam, Alan; Slevin, Nicholas J; Mackay, Ranald I; van Herk, Marcel

    2016-12-21

    Contour propagation is an essential component of adaptive radiotherapy, but current contour propagation algorithms are not yet sufficiently accurate to be used without manual supervision. Manual review of propagated contours is time-consuming, making routine implementation of real-time adaptive radiotherapy unrealistic. Automated methods of monitoring the performance of contour propagation algorithms are therefore required. We have developed an automated workflow for patient-specific quality control of contour propagation and validated it on a cohort of head and neck patients, on which parotids were outlined by two observers. Two types of error were simulated-mislabelling of contours and introducing noise in the scans before propagation. The ability of the workflow to correctly predict the occurrence of errors was tested, taking both sets of observer contours as ground truth, using receiver operator characteristic analysis. The area under the curve was 0.90 and 0.85 for the observers, indicating good ability to predict the occurrence of errors. This tool could potentially be used to identify propagated contours that are likely to be incorrect, acting as a flag for manual review of these contours. This would make contour propagation more efficient, facilitating the routine implementation of adaptive radiotherapy.

  4. 螺杆泵采油系统杆柱的扭转振动特性分析%The twisting vibration characteristic analysis of the sucker rod string for progressing cavity pump oil production system

    Institute of Scientific and Technical Information of China (English)

    彭勇

    2001-01-01

    对直井中用于驱动井下螺杆泵的旋转级次抽油杆柱建立了扭转振动分析模型,推导出了该级次抽油杆柱扭转振动频率的计算公式,建立了级次杆柱扭振固有基频与单级杆柱固有基频之间的关系。计算表明,泵深在700~1800m时,常用的二级抽油杆柱组合的扭振固有基频为22~58r/min,低于螺杆泵的工作转速区,这完全不同于有杆泵抽油系统。指出,由于螺杆泵采油系统的工作转速区高于其杆柱扭振固有基频,在选定螺杆泵采油系统的工作转速时,除考虑杆柱的基频外,还应考虑杆柱的扭振高次谐波频率,这样可以避免系统工作在高次谐波共振区,而且有利于避免系统工作转速在穿越高次谐波对应的转速时系统的失速;在设计螺杆泵采油系统杆柱组合时,应考虑组合杆柱对杆柱扭振基频的提高,尤其要注意常用的二级杆柱组合时杆长比接近50%的情况。%In this paper it makes a twisting vibration analysis model of therotary sucker rod string,which is used to drive the progressing cavity pump in vertical well,and deduces the calculating formula of the sucker rod string's twisting vibration frequency.then sets up a relation between sucker rod string's twisting vibration natural base frequency and single sucker rod's natural frequency.According to the calculation,the twisting vibration base frequency of common two-staged sucker rod string is from 20~58 rpm when pump is working within the depth of 700~1 800 m,which is below the working speed of progressing cavity pump,and it is completely different from the sucker rod pump oil production system.The paper points out that because the working speed of progressing cavity pump oil production system is higher than the twisting vibration base frequency of its sucker rod string,when we choose the working speed of the system,it is necessary to consider the base frequency as well as the high harmonic

  5. "Twisted Beam" SEE Observations of Ionospheric Heating from HAARP

    Science.gov (United States)

    Briczinski, S. J.; Bernhardt, P. A.; Siefring, C. L.; Han, S.-M.; Pedersen, T. R.; Scales, W. A.

    2015-10-01

    Nonlinear interactions of high power HF radio waves in the ionosphere provide aeronomers with a unique space-based laboratory capability. The High-Frequency Active Auroral Research Program (HAARP) in Gakona, Alaska is the world's largest heating facility, yielding effective radiated powers in the gigawatt range. New results are present from HAARP experiments using a "twisted beam" excitation mode. Analysis of twisted beam heating shows that the SEE results obtained are identical to more traditional patterns. One difference in the twisted beam mode is the heating region produced is in the shape of a ring as opposed to the more traditional "solid spot" region from a pencil beam. The ring heating pattern may be more conducive to the creation of stable artificial airglow layers because of the horizontal structure of the ring. The results of these runs include artificial layer creation and evolution as pertaining to the twisted beam pattern. The SEE measurements aid the interpretation of the twisted beam interactions in the ionosphere.

  6. Body contouring after obesity surgery is associated with a weight loss benefit among patients.

    Science.gov (United States)

    Agarwal, Shailesh; Shenaq, Deana; Teven, Chad M; Prachand, Vivek; Roughton, Michelle; Zachary, Lawrence

    2017-09-01

    Patients who undergo obesity surgery often require body contouring procedures to eliminate excess skin. Recent studies suggest that body contouring surgery may provide psychological benefits to patients after obesity surgery. However, it remains unclear how body contouring may affect weight loss maintenance after obesity surgery. This is a retrospective review of patients who underwent obesity surgery with or without body contouring at a single institution from 2000 to 2005. Charts were reviewed for demographic, medical, and surgical information. The primary outcome of interest was the difference in weight loss maintenance among patients who underwent body contouring versus those who did not. A total of 318 patients were included for analysis in this study, of which 70 underwent obesity surgery with body contouring and 248 underwent obesity surgery without body contouring. The mean change in BMI among patients who did not undergo body contouring was 19.7 kg/m(2). The mean change in BMI among patients who underwent body contouring was 22.1 kg/m(2). Among patients who underwent body contouring surgery, 2.9% (2/70) of patients did not maintain at least a 20% decrease in body weight during the entire follow-up period (mean follow-up time 92.2 months). Among patients who did not undergo body contouring surgery, 10% (25/248) of patients did not maintain at least a 20% decrease in body weight during the entire follow-up period (mean follow-up time 39.0 months) (χ(2) = 3.67, p = 0.055). Body contouring surgery may have a positive effect on weight loss maintenance after body contouring determined from the mean weight change and on percentage of patients who maintain at least a 20% decrease in body weight. Copyright © 2017. Published by Elsevier Ltd.

  7. Renormalization constants for 2-twist operators in twisted mass QCD

    CERN Document Server

    Alexandrou, C; Korzec, T; Panagopoulos, H; Stylianou, F

    2010-01-01

    Perturbative and non-perturbative results on the renormalization constants of the fermion field and the twist-2 fermion bilinears are presented with emphasis on the non-perturbative evaluation of the one-derivative twist-2 vector and axial vector operators. Non-perturbative results are obtained using the twisted mass Wilson fermion formulation employing two degenerate dynamical quarks and the tree-level Symanzik improved gluon action. The simulations have been performed for pion masses in the range of about 450-260 MeV and at three values of the lattice spacing $a$ corresponding to $\\beta=3.9, 4.05, 4.20$. Subtraction of ${\\cal O}(a^2)$ terms is carried out by performing the perturbative evaluation of these operators at 1-loop and up to ${\\cal O}(a^2)$. The renormalization conditions are defined in the RI$'$-MOM scheme, for both perturbative and non-perturbative results. The renormalization factors, obtained for different values of the renormalization scale, are evolved perturbatively to a reference scale set...

  8. Adaptive dual-layer super-twisting control and observation

    Science.gov (United States)

    Edwards, Christopher; Shtessel, Yuri

    2016-09-01

    In this paper, a super-twisting-like structure with adaptive gains is proposed. The structure is parameterised by two scalar gains, both of which adapt, and by an additional time-varying term. The magnitudes of the adaptive terms are allowed to both increase and decrease as appropriate so that they are as small as possible, in the sense that they do not unnecessarily over-bound the uncertainty, and yet are large enough to sustain a sliding motion. In the paper, a new time varying gain is incorporated into the traditional super-twisting architecture. The proposed adaption law has a dual-layer structure which is formally analyzed using Lyapunov techniques. The additional term has the effect of simplifying the stability analysis whilst guaranteeing the second-order sliding mode properties of the traditional super-twisting scheme.

  9. Template preparation of twisted nanoparticles of mesoporous silica

    Institute of Scientific and Technical Information of China (English)

    Kui Niu; Zhongbin Ni; Chengwu Fu; Tatsuo Kaneko; Mingqing Chen

    2011-01-01

    Optical isomers of N-lauroyl-L-(or-D-) alanine sodium salt {C12-L-(or-D-)AlaS} surfactants were used for the preparation of mesoporous silica nanoparticles with a twisted hexagonal rod-like morphology. Thermogravimetric analysis (TGA) was used to determine the temperature for template removal. Circular dichroism (CD) spectra of the surfactant solution with various compositions illustrated the formation and supramolecular assembly of protein-like molecular architecture leading to formation of twisted nanoparticles. Scanning electron microscopy (SEM),high-resolution transmission electron microscopy (HRTEM)and X-ray powder diffraction (XRD) patterns of these as-synthesized mesoporous silica confirmed that the twisted morphology of these nanoparticles was closely related to the supramolecular-assembled complex of amino acid surfactants.

  10. Bend-twist coupling potential of wind turbine blades

    DEFF Research Database (Denmark)

    Fedorov, Vladimir; Berggreen, Christian

    2014-01-01

    In the present study an evaluation of the potential for bend-twist coupling effects in wind turbine blades is addressed. A method for evaluation of the coupling magnitude based on the results of finite element modeling and full-field displacement measurements obtained by experiments is developed...... and tested on small-scale coupled composite beams. In the proposed method the coupling coefficient for a generic beam is introduced based on the Euler-Bernoulli beam formulation. By applying the developed method for analysis of a commercial wind turbine blade structure it is demonstrated that a bend......-twist coupling magnitude of up to 0.2 is feasible to achieve in the baseline blade structure made of glass-fiber reinforced plastics. Further, by substituting the glass-fibers with carbon-fibers the coupling effect can be increased to 0.4. Additionally, the effect of introduction of bend-twist coupling...

  11. Automatic Detection of Adenocarcinoma using Active Contours

    Directory of Open Access Journals (Sweden)

    NeelapalaAnilKumar

    2013-09-01

    Full Text Available CT scan is the one of the image representation for abdomen, where the tumour to be located and specified effectively with clarity, by the medical expert. This role can be hold by using one of the image processing techniques called segmentation. Image segmentation is the technique which isolates the image into different regions to simplify the image and identify the Tumour easily. Image segmentation has been extensively studied by various approaches. This work, focus on the one of the image segmentation technique with a new regularization term that yields an unsupervised segmentation model which identifies different Tumour locations in a given CT image. Active contours form a boundary around a particular part of the image based on an energy function. The energy function may include intensity values of pixels or gradient values. Chen-Vase method of active contour algorithm is adopted for image segmentation. The segmentation is done after properly masking of CT scan image. The cancer prone area is generalized prior to the masking of the image. Effected abdomen cancer can be identified for better analysis of medical experts using image processing MATLAB tools. This paper describes a new method to detect and extract the features in CT scan images, which shows good performance in detection of difficult features. And the developed technique makes use of major image processing methods and fundamentals to detect the cancer with minimum possible human interaction.

  12. The twist box domain is required for Twist1-induced prostate cancer metastasis.

    Science.gov (United States)

    Gajula, Rajendra P; Chettiar, Sivarajan T; Williams, Russell D; Thiyagarajan, Saravanan; Kato, Yoshinori; Aziz, Khaled; Wang, Ruoqi; Gandhi, Nishant; Wild, Aaron T; Vesuna, Farhad; Ma, Jinfang; Salih, Tarek; Cades, Jessica; Fertig, Elana; Biswal, Shyam; Burns, Timothy F; Chung, Christine H; Rudin, Charles M; Herman, Joseph M; Hales, Russell K; Raman, Venu; An, Steven S; Tran, Phuoc T

    2013-11-01

    Twist1, a basic helix-loop-helix transcription factor, plays a key role during development and is a master regulator of the epithelial-mesenchymal transition (EMT) that promotes cancer metastasis. Structure-function relationships of Twist1 to cancer-related phenotypes are underappreciated, so we studied the requirement of the conserved Twist box domain for metastatic phenotypes in prostate cancer. Evidence suggests that Twist1 is overexpressed in clinical specimens and correlated with aggressive/metastatic disease. Therefore, we examined a transactivation mutant, Twist1-F191G, in prostate cancer cells using in vitro assays, which mimic various stages of metastasis. Twist1 overexpression led to elevated cytoskeletal stiffness and cell traction forces at the migratory edge of cells based on biophysical single-cell measurements. Twist1 conferred additional cellular properties associated with cancer cell metastasis including increased migration, invasion, anoikis resistance, and anchorage-independent growth. The Twist box mutant was defective for these Twist1 phenotypes in vitro. Importantly, we observed a high frequency of Twist1-induced metastatic lung tumors and extrathoracic metastases in vivo using the experimental lung metastasis assay. The Twist box was required for prostate cancer cells to colonize metastatic lung lesions and extrathoracic metastases. Comparative genomic profiling revealed transcriptional programs directed by the Twist box that were associated with cancer progression, such as Hoxa9. Mechanistically, Twist1 bound to the Hoxa9 promoter and positively regulated Hoxa9 expression in prostate cancer cells. Finally, Hoxa9 was important for Twist1-induced cellular phenotypes associated with metastasis. These data suggest that the Twist box domain is required for Twist1 transcriptional programs and prostate cancer metastasis. Targeting the Twist box domain of Twist1 may effectively limit prostate cancer metastatic potential. ©2013 AACR.

  13. "Twisted" black holes are unphysical

    CERN Document Server

    Gray, Finnian; Schuster, Sebastian; Visser, Matt

    2016-01-01

    So-called "twisted" black holes have recently been proposed by Zhang (1609.09721 [gr-qc]), and further considered by Chen and Jing (1610.00886 [gr-qc]), and more recently by Ong (1610.05757 [gr-qc]). While these spacetimes are certainly Ricci-flat, and so mathematically satisfy the vacuum Einstein equations, they are also merely minor variants on Taub--NUT spacetimes. Consequently they exhibit several unphysical features that make them quite unreasonable as realistic astrophysical objects. Specifically, these "twisted" black holes are not (globally) asymptotically flat. Furthermore, they contain closed timelike curves that are not hidden behind any event horizon --- the most obvious of these closed timelike curves are small azimuthal circles around the rotation axis, but the effect is more general. The entire region outside the horizon is infested with closed timelike curves.

  14. Polarization twist in perovskite ferrielectrics

    Science.gov (United States)

    Kitanaka, Yuuki; Hirano, Kiyotaka; Ogino, Motohiro; Noguchi, Yuji; Miyayama, Masaru; Moriyoshi, Chikako; Kuroiwa, Yoshihiro

    2016-01-01

    Because the functions of polar materials are governed primarily by their polarization response to external stimuli, the majority of studies have focused on controlling polar lattice distortions. In some perovskite oxides, polar distortions coexist with nonpolar tilts and rotations of oxygen octahedra. The interplay between nonpolar and polar instabilities appears to play a crucial role, raising the question of how to design materials by exploiting their coupling. Here, we introduce the concept of ‘polarization twist’, which offers enhanced control over piezoelectric responses in polar materials. Our experimental and theoretical studies provide direct evidence that a ferrielectric perovskite exhibits a large piezoelectric response because of extended polar distortion, accompanied by nonpolar octahedral rotations, as if twisted polarization relaxes under electric fields. The concept underlying the polarization twist opens new possibilities for developing alternative materials in bulk and thin-film forms. PMID:27586824

  15. Polarization twist in perovskite ferrielectrics

    Science.gov (United States)

    Kitanaka, Yuuki; Hirano, Kiyotaka; Ogino, Motohiro; Noguchi, Yuji; Miyayama, Masaru; Moriyoshi, Chikako; Kuroiwa, Yoshihiro

    2016-09-01

    Because the functions of polar materials are governed primarily by their polarization response to external stimuli, the majority of studies have focused on controlling polar lattice distortions. In some perovskite oxides, polar distortions coexist with nonpolar tilts and rotations of oxygen octahedra. The interplay between nonpolar and polar instabilities appears to play a crucial role, raising the question of how to design materials by exploiting their coupling. Here, we introduce the concept of ‘polarization twist’, which offers enhanced control over piezoelectric responses in polar materials. Our experimental and theoretical studies provide direct evidence that a ferrielectric perovskite exhibits a large piezoelectric response because of extended polar distortion, accompanied by nonpolar octahedral rotations, as if twisted polarization relaxes under electric fields. The concept underlying the polarization twist opens new possibilities for developing alternative materials in bulk and thin-film forms.

  16. Brightness Alteration with Interweaving Contours

    Directory of Open Access Journals (Sweden)

    Sergio Roncato

    2012-12-01

    Full Text Available Chromatic induction is observed whenever the perceived colour of a target surface shifts towards the hue of a neighbouring surface. Some vivid manifestations may be seen in a white background where thin coloured lines have been drawn (assimilation or when lines of different colours are collinear (neon effect or adjacent (watercolour to each other. This study examines a particular colour induction that manifests in concomitance with an opposite effect of colour saturation (or anti-spread. The two phenomena can be observed when a repetitive pattern is drawn in which outline thin contours intercept wider contours or surfaces, colour spreading appear to fill the surface occupied by surfaces or thick lines whereas the background traversed by thin lines is seen as brighter or filled of a saturated white. These phenomena were first observed by Bozzi (1975 and Kanizsa (1979 in figural conditions that did not allow them to document their conjunction. Here we illustrate various manifestations of this twofold phenomenon and compare its effects with the known effects of brightness and colour induction. Some conjectures on the nature of these effects are discussed.

  17. Twisted Chern-Simons supergravity

    Energy Technology Data Exchange (ETDEWEB)

    Castellani, L. [Dipartimento di Scienze e Innovazione Tecnologica, Univ. del Piemonte Orientale, Alessandria (Italy); INFN Gruppo collegato di Alessandria (Italy)

    2014-09-11

    We present a noncommutative version of D = 5 Chern-Simons supergravity, where noncommutativity is encoded in a *-product associated to an abelian Drinfeld twist. The theory is invariant under diffeomorphisms, and under the *-gauge supergroup SU(2,2 vertical stroke 4), including Lorentz and N = 4 local supersymmetries. (Copyright copyright 2014 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  18. Counting Polyominoes on Twisted Cylinders

    OpenAIRE

    Barequet, Gill; Moffie, Micha; Ribó, Ares; Rote, Günter

    2005-01-01

    International audience; We improve the lower bounds on Klarner's constant, which describes the exponential growth rate of the number of polyominoes (connected subsets of grid squares) with a given number of squares. We achieve this by analyzing polyominoes on a different surface, a so-called $\\textit{twisted cylinder}$ by the transfer matrix method. A bijective representation of the "states'' of partial solutions is crucial for allowing a compact representation of the successive iteration vec...

  19. New twist on artificial muscles

    Science.gov (United States)

    Haines, Carter S.; Li, Na; Spinks, Geoffrey M.; Aliev, Ali E.; Di, Jiangtao; Baughman, Ray H.

    2016-01-01

    Lightweight artificial muscle fibers that can match the large tensile stroke of natural muscles have been elusive. In particular, low stroke, limited cycle life, and inefficient energy conversion have combined with high cost and hysteretic performance to restrict practical use. In recent years, a new class of artificial muscles, based on highly twisted fibers, has emerged that can deliver more than 2,000 J/kg of specific work during muscle contraction, compared with just 40 J/kg for natural muscle. Thermally actuated muscles made from ordinary polymer fibers can deliver long-life, hysteresis-free tensile strokes of more than 30% and torsional actuation capable of spinning a paddle at speeds of more than 100,000 rpm. In this perspective, we explore the mechanisms and potential applications of present twisted fiber muscles and the future opportunities and challenges for developing twisted muscles having improved cycle rates, efficiencies, and functionality. We also demonstrate artificial muscle sewing threads and textiles and coiled structures that exhibit nearly unlimited actuation strokes. In addition to robotics and prosthetics, future applications include smart textiles that change breathability in response to temperature and moisture and window shutters that automatically open and close to conserve energy. PMID:27671626

  20. DVCS on the nucleon to the twist-3 accuracy

    CERN Document Server

    Kivel, N A

    2001-01-01

    The amplitude of the deeply virtual Compton scattering off nucleon is computed to the twist-3 accuracy in the Wandzura-Wilczek (WW) approximation. The result is presented in the form which can be easily used for analysis of DVCS observables.

  1. The perception of 3D shape from planar cut contours.

    Science.gov (United States)

    Egan, Eric J L; Todd, James T; Phillips, Flip

    2011-10-01

    A new computational analysis is described for estimating 3D shapes from orthographic images of surfaces that are textured with planar cut contours. For any given contour pattern, this model provides a family of possible interpretations that are all related by affine scaling and shearing transformations in depth, depending on the specific values of its free parameters that are used to compute the shape estimate. Two psychophysical experiments were performed in an effort to compare the model predictions with observers' judgments of 3D shape for developable and non-developable surfaces. The results reveal that observers' perceptions can be systematically distorted by affine scaling and shearing transformations in depth and that the magnitude and direction of these distortions vary systematically with the 3D orientations of the contour planes.

  2. Twisting Flux Tubes as a cause of Micro-Flaring Activity

    CERN Document Server

    Jess, D B; Mathioudakis, M; Keenan, F P; Andic, A; Bloomfield, D S

    2007-01-01

    High-cadence optical observations of an H-alpha blue-wing bright point near solar AR NOAA 10794 are presented. The data were obtained with the Dunn Solar Telescope at the National Solar Observatory/Sacramento Peak using a newly developed camera system, the Rapid Dual Imager. Wavelet analysis is undertaken to search for intensity-related oscillatory signatures, and periodicities ranging from 15 to 370 s are found with significance levels exceeding 95%. During two separate microflaring events, oscillation sites surrounding the bright point are observed to twist. We relate the twisting of the oscillation sites to the twisting of physical flux tubes, thus giving rise to reconnection phenomena. We derive an average twist velocity of 8.1 km/s and detect a peak in the emitted flux between twist angles of 180 and 230 degrees.

  3. Experimental study of yttrium barium copper oxide superconducting tape’s critical current under twisting moment

    Indian Academy of Sciences (India)

    Ziauddin Khan; Ananya Kundu; Subrata Pradhan

    2013-10-01

    Critical current (c) characteristics of 2G YBCO superconducting tape under the influence of twisting moment was experimentally investigated at varying current ramp rates in the self-field. Under a uniform twist, the degradation in the current-carrying capacity of YBCO tape up to 30% was observed at 77 K. The degradation is largely attributed to the shear stress and torsional shear strain resulting from the twisting. The superconductor to resistive transition index, , is also found to behave in an identical manner with increase in the twisting. Finite element analysis (FEA) of the tape in the experimental configuration with twisting moment being applied on to it has been carried out in COMSOL. The torsional strain calculated analytically as per the experimental configuration matches closely with that of FEA results, which shows that the critical current degradation is a function of strain.

  4. Contours, 2 Ft. Contours, Published in 2006, North Georgia College and State University.

    Data.gov (United States)

    NSGIC GIS Inventory (aka Ramona) — This Contours dataset, was produced all or in part from LIDAR information as of 2006. It is described as '2 Ft. Contours'. Data by this publisher are often provided...

  5. NY_GOME_CONTOURS: New York Bight and Gulf of Maine bathymetric contours

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — This bathymetric shapefile contains 10 m contours for the continental shelf and 100 m beyond the 200 m shelf edge. The contours have been derived from the National...

  6. NY_GOME_CONTOURS: New York Bight and Gulf of Maine bathymetric contours

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — This bathymetric shapefile contains 10 m contours for the continental shelf and 100 m beyond the 200 m shelf edge. The contours have been derived from the National...

  7. Contours, Two Foot Contours, Published in 2007, Not Applicable scale, Dunn County, WI.

    Data.gov (United States)

    NSGIC GIS Inventory (aka Ramona) — This Contours dataset, published at Not Applicable scale, was produced all or in part from LIDAR information as of 2007. It is described as 'Two Foot Contours'....

  8. Noncommutative principal bundles through twist deformation

    CERN Document Server

    Aschieri, Paolo; Pagani, Chiara; Schenkel, Alexander

    2016-01-01

    We construct noncommutative principal bundles deforming principal bundles with a Drinfeld twist (2-cocycle). If the twist is associated with the structure group then we have a deformation of the fibers. If the twist is associated with the automorphism group of the principal bundle, then we obtain noncommutative deformations of the base space as well. Combining the two twist deformations we obtain noncommutative principal bundles with both noncommutative fibers and base space. More in general, the natural isomorphisms proving the equivalence of a closed monoidal category of modules and its twist related one are used to obtain new Hopf-Galois extensions as twists of Hopf-Galois extensions. A sheaf approach is also considered, and examples presented.

  9. Twist-1 Up-Regulation in Carcinoma Correlates to Poor Survival

    Directory of Open Access Journals (Sweden)

    Alimujiang Wushou

    2014-11-01

    Full Text Available Epithelial-to-mesenchymal transition (EMT facilitates tumor metastasis. Twist is a basic helix-loop-helix protein that modulates many target genes through E-box-responsive elements. There are two twist-like proteins, Twist-1 and Twist-2, sharing high structural homology in mammals. Twist-1 was found to be a key factor in the promotion of metastasis of cancer cells, and is known to induce EMT. Twist-1 participation in carcinoma progression and metastasis has been reported in a variety of tumors. However, controversy exists concerning the correlation between Twist-1 and prognostic value with respect to carcinoma. A systematic review and meta-analysis were performed to determine whether the expression of Twist-1 was associated with the prognosis of carcinoma patients. This analysis included 17 studies: four studies evaluated lung cancer, three evaluated head and neck cancer, two evaluated breast cancer, two evaluated esophageal cancer, two evaluated liver cancer and one each evaluated osteosarcoma, bladder, cervical and ovarian cancer. A total of 2006 patients were enrolled in these studies, and the median trial sample size was 118 patients. Twist-1 expression was associated with worse overall survival (OS at both 3 years (hazard ratio “HR” for death = 2.13, 95% CI = 1.86 to 2.45, p < 0.001 and 5 years (HR for death = 2.01, 95% CI = 1.76 to 2.29, p < 0.001. Expression of Twist-1 is associated with worse survival in carcinoma.

  10. Epigenetic inactivation of TWIST2 in acute lymphoblastic leukemia modulates proliferation, cell survival and chemosensitivity

    Science.gov (United States)

    Thathia, Shabnam H.; Ferguson, Stuart; Gautrey, Hannah E.; van Otterdijk, Sanne D.; Hili, Michela; Rand, Vikki; Moorman, Anthony V.; Meyer, Stefan; Brown, Robert; Strathdee, Gordon

    2012-01-01

    Background Altered regulation of many transcription factors has been shown to be important in the development of leukemia. TWIST2 modulates the activity of a number of important transcription factors and is known to be a regulator of hematopoietic differentiation. Here, we investigated the significance of epigenetic regulation of TWIST2 in the control of cell growth and survival and in response to cytotoxic agents in acute lymphoblastic leukemia. Design and Methods TWIST2 promoter methylation status was assessed quantitatively, by combined bisulfite and restriction analysis (COBRA) and pyrosequencing assays, in multiple types of leukemia and TWIST2 expression was determined by quantitative reverse transcriptase polymerase chain reaction analysis. The functional role of TWIST2 in cell proliferation, survival and response to chemotherapy was assessed in transient and stable expression systems. Results We found that TWIST2 was inactivated in more than 50% of cases of childhood and adult acute lymphoblastic leukemia through promoter hypermethylation and that this epigenetic regulation was especially prevalent in RUNX1-ETV6-driven cases. Re-expression of TWIST2 in cell lines resulted in a dramatic reduction in cell growth and induction of apoptosis in the Reh cell line. Furthermore, re-expression of TWIST2 resulted in increased sensitivity to the chemotherapeutic agents etoposide, daunorubicin and dexamethasone and TWIST2 hypermethylation was almost invariably found in relapsed adult acute lymphoblastic leukemia (91% of samples hypermethylated). Conclusions This study suggests a dual role for epigenetic inactivation of TWIST2 in acute lymphoblastic leukemia, initially through altering cell growth and survival properties and subsequently by increasing resistance to chemotherapy. PMID:22058208

  11. The Twist Limit for Bipolar Active Regions

    Science.gov (United States)

    Moore, Ron; Falconer, David; Gary, Allen

    2008-01-01

    We present new evidence that further supports the standard idea that active regions are emerged magnetic-flux-rope omega loops. When the axial magnetic twist of a cylindrical flux rope exceeds a critical amount, the flux rope becomes unstable to kinking, and the excess axial twist is converted into writhe twist by the kinking. This suggests that, if active regions are emerged omega loops, then (1) no active region should have magnetic twist much above the limit set by kinking, (2) active regions having twist near the limit should often arise from kinked omega loops, and (3) since active regions having large delta sunspots are outstandingly twisted, these arise from kinked omega loops and should have twist near the limit for kinking. From each of 36 vector magnetograms of bipolar active regions, we have measured (1) the total flux of the vertical field above 100 G, (2) the area covered by this flux, and (3) the net electric current that arches over the polarity inversion line. These three quantities yield an estimate of the axial magnetic twist in a simple model cylindrical flux rope that corresponds to the top of the active region s hypothetical omega loop prior to emergence. In all 36 cases, the estimated twist is below the critical limit for kinking. The 11 most twisted active regions (1) have estimated twist within a factor of approx.3 of the limit, and (2) include all of our 6 active regions having large delta sunspots. Thus, our observed twist limit for bipolar active regions is in good accord with active regions being emerged omega loops.

  12. Automatic Contour Extraction from 2D Image

    Directory of Open Access Journals (Sweden)

    Panagiotis GIOANNIS

    2011-03-01

    Full Text Available Aim: To develop a method for automatic contour extraction from a 2D image. Material and Method: The method is divided in two basic parts where the user initially chooses the starting point and the threshold. Finally the method is applied to computed tomography of bone images. Results: An interesting method is developed which can lead to a successful boundary extraction of 2D images. Specifically data extracted from a computed tomography images can be used for 2D bone reconstruction. Conclusions: We believe that such an algorithm or part of it can be applied on several other applications for shape feature extraction in medical image analysis and generally at computer graphics.

  13. DVCS amplitude with kinematical twist-3 terms

    CERN Document Server

    Radyushkin, A V

    2000-01-01

    We compute the amplitude of deeply virtual Compton scattering (DVCS) using the calculus of QCD string operators in coordinate representation. To restore the electromagnetic gauge invariance (transversality) of the twist-2 amplitude we include the operators of twist-3 which appear as total derivatives of twist-2 operators. Our results are equivalent to a Wandzura-Wilczek approximation for twist-3 skewed parton distributions. We find that this approximation gives a finite result for the amplitude of a longitudinally polarized virtual photon, while the amplitude for transverse polarization is divergent, i.e., factorization breaks down in this term.

  14. Contour extracting networks in early extrastriate cortex

    NARCIS (Netherlands)

    Dumoulin, Serge O.; Hess, Robert F.; May, Keith A.; Harvey, Ben M.; Rokers, Bas; Barendregt, Martijn

    2014-01-01

    Neurons in the visual cortex process a local region of visual space, but in order to adequately analyze natural images, neurons need to interact. The notion of an ''association field'' proposes that neurons interact to extract extended contours. Here, we identify the site and properties of contour

  15. RFP for the Comet Nuclei Tour (CONTOUR)

    DEFF Research Database (Denmark)

    Jørgensen, John Leif; Madsen, Peter Buch; Betto, Maurizio

    1999-01-01

    This document describes the ASC Star Tracker (performance, functionality, requirements etc.) to The Johns Hopkins University - Applied Physics Laboratory for their Comet Nuclei TOUR (CONTOUR) Program.......This document describes the ASC Star Tracker (performance, functionality, requirements etc.) to The Johns Hopkins University - Applied Physics Laboratory for their Comet Nuclei TOUR (CONTOUR) Program....

  16. Contour extracting networks in early extrastriate cortex

    NARCIS (Netherlands)

    Dumoulin, Serge O.; Hess, Robert F.; May, Keith A.; Harvey, Ben M.; Rokers, Bas; Barendregt, Martijn

    2014-01-01

    Neurons in the visual cortex process a local region of visual space, but in order to adequately analyze natural images, neurons need to interact. The notion of an ''association field'' proposes that neurons interact to extract extended contours. Here, we identify the site and properties of contour i

  17. Twisted conjugacy in braid groups

    CERN Document Server

    González-Meneses, Juan

    2011-01-01

    In this note we solve the twisted conjugacy problem for braid groups, i.e. we propose an algorithm which, given two braids $u,v\\in B_n$ and an automorphism $\\phi \\in Aut (B_n)$, decides whether $v=(\\phi (x))^{-1}ux$ for some $x\\in B_n$. As a corollary, we deduce that each group of the form $B_n \\rtimes H$, a semidirect product of the braid group $B_n$ by a torsion-free hyperbolic group $H$, has solvable conjugacy problem.

  18. Higher-Twist Dynamics in Large Transverse Momentum Hadron Production

    Energy Technology Data Exchange (ETDEWEB)

    Arleo, Francois; /Annecy, LAPTH; Brodsky, Stanley J.; /SLAC; Hwang, Dae Sung; /Sejong U.; Sickles, Anne M.; /Brookhaven

    2009-12-17

    A scaling law analysis of the world data on inclusive large-p{sub {perpendicular}} hadron production in hadronic collisions is carried out. A significant deviation from leading-twist perturbative QCD predictions at next-to-leading order is reported. The observed discrepancy is largest at high values of x{sub {perpendicular}} = 2p{sub {perpendicular}}/{radical}s. In contrast, the production of prompt photons and jets exhibits the scaling behavior which is close to the conformal limit, in agreement with the leading-twist expectation. These results bring evidence for a non-negligible contribution of higher-twist processes in large-p{sub {perpendicular}} hadron production in hadronic collisions, where the hadron is produced directly in the hard subprocess rather than by gluon or quark jet fragmentation. Predictions for scaling exponents at RHIC and LHC are given, and it is suggested to trigger the isolated large-p{sub {perpendicular}} hadron production to enhance higher-twist processes.

  19. Retroperitoneal Sarcoma Target Volume and Organ at Risk Contour Delineation Agreement Among NRG Sarcoma Radiation Oncologists

    Energy Technology Data Exchange (ETDEWEB)

    Baldini, Elizabeth H., E-mail: ebaldini@partners.org [Department of Radiation Oncology, Dana-Farber Cancer Institute, Brigham and Women' s Hospital, Boston, Massachusetts (United States); Abrams, Ross A. [Department of Radiation Oncology, Rush University Medical Center, Chicago, Illinois (United States); Bosch, Walter [Department of Radiation Oncology, Washington University, St. Louis, Missouri (United States); Roberge, David [Department of Radiation Oncology, Centre Hospitalier de l' Universite de Montreal, Montreal, Quebec (Canada); Haas, Rick L.M. [Department of Radiotherapy, Netherlands Cancer Institute, Amsterdam (Netherlands); Catton, Charles N. [Department of Radiation Oncology, Princess Margaret Cancer Centre, Toronto, Ontario (Canada); Indelicato, Daniel J. [Department of Radiation Oncology, University of Florida Medical Center, Jacksonville, Florida (United States); Olsen, Jeffrey R. [Department of Radiation Oncology, Washington University, St. Louis, Missouri (United States); Deville, Curtiland [Department of Radiation Oncology, University of Pennsylvania, Philadelphia, Pennsylvania (United States); Chen, Yen-Lin [Department of Radiation Oncology, Massachusetts General Hospital, Boston, Massachusetts (United States); Finkelstein, Steven E. [Translational Research Consortium, 21st Century Oncology, Scottsdale, Arizona (United States); DeLaney, Thomas F. [Department of Radiation Oncology, Massachusetts General Hospital, Boston, Massachusetts (United States); Wang, Dian [Department of Radiation Oncology, Rush University Medical Center, Chicago, Illinois (United States)

    2015-08-01

    Purpose: The purpose of this study was to evaluate the variability in target volume and organ at risk (OAR) contour delineation for retroperitoneal sarcoma (RPS) among 12 sarcoma radiation oncologists. Methods and Materials: Radiation planning computed tomography (CT) scans for 2 cases of RPS were distributed among 12 sarcoma radiation oncologists with instructions for contouring gross tumor volume (GTV), clinical target volume (CTV), high-risk CTV (HR CTV: area judged to be at high risk of resulting in positive margins after resection), and OARs: bowel bag, small bowel, colon, stomach, and duodenum. Analysis of contour agreement was performed using the simultaneous truth and performance level estimation (STAPLE) algorithm and kappa statistics. Results: Ten radiation oncologists contoured both RPS cases, 1 contoured only RPS1, and 1 contoured only RPS2 such that each case was contoured by 11 radiation oncologists. The first case (RPS 1) was a patient with a de-differentiated (DD) liposarcoma (LPS) with a predominant well-differentiated (WD) component, and the second case (RPS 2) was a patient with DD LPS made up almost entirely of a DD component. Contouring agreement for GTV and CTV contours was high. However, the agreement for HR CTVs was only moderate. For OARs, agreement for stomach, bowel bag, small bowel, and colon was high, but agreement for duodenum (distorted by tumor in one of these cases) was fair to moderate. Conclusions: For preoperative treatment of RPS, sarcoma radiation oncologists contoured GTV, CTV, and most OARs with a high level of agreement. HR CTV contours were more variable. Further clarification of this volume with the help of sarcoma surgical oncologists is necessary to reach consensus. More attention to delineation of the duodenum is also needed.

  20. Twisting the N=2 string

    Science.gov (United States)

    Ketov, Sergei V.; Lechtenfeld, Olaf; Parkes, Andrew J.

    1995-03-01

    The most general homogeneous monodromy conditions in N=2 string theory are classified in terms of the conjugacy classes of the global symmetry group U(1,1)⊗openZ2. For classes which generate a discrete subgroup Γ, the corresponding target space backgrounds openC1,1/Γ include half spaces, complex orbifolds, and tori. We propose a generalization of the intercept formula to matrix-valued twists, but find massless physical states only for Γ=open1 (untwisted) and Γ=openZ2 (in the manner of Mathur and Mukhi), as well as for Γ being a parabolic element of U(1,1). In particular, the 16 openZ2-twisted sectors of the N=2 string are investigated, and the corresponding ground states are identified via bosonization and BRST cohomology. We find enough room for an extended multiplet of ``spacetime'' supersymmetry, with the number of supersymmetries being dependent on global ``spacetime'' topology. However, world-sheet locality for the chiral vertex operators does not permit interactions among all massless ``spacetime'' fermions.

  1. Symmetry fractionalization and twist defects

    Science.gov (United States)

    Tarantino, Nicolas; Lindner, Netanel H.; Fidkowski, Lukasz

    2016-03-01

    Topological order in two-dimensions can be described in terms of deconfined quasiparticle excitations—anyons—and their braiding statistics. However, it has recently been realized that this data does not completely describe the situation in the presence of an unbroken global symmetry. In this case, there can be multiple distinct quantum phases with the same anyons and statistics, but with different patterns of symmetry fractionalization—termed symmetry enriched topological order. When the global symmetry group G, which we take to be discrete, does not change topological superselection sectors—i.e. does not change one type of anyon into a different type of anyon—one can imagine a local version of the action of G around each anyon. This leads to projective representations and a group cohomology description of symmetry fractionalization, with the second cohomology group {H}2(G,{{ A }}{{abelian}}) being the relevant group. In this paper, we treat the general case of a symmetry group G possibly permuting anyon types. We show that despite the lack of a local action of G, one can still make sense of a so-called twisted group cohomology description of symmetry fractionalization, and show how this data is encoded in the associativity of fusion rules of the extrinsic ‘twist’ defects of the symmetry. Furthermore, building on work of Hermele (2014 Phys. Rev. B 90 184418), we construct a wide class of exactly-solvable models which exhibit this twisted symmetry fractionalization, and connect them to our formal framework.

  2. Multiple Twisted -Euler Numbers and Polynomials Associated with -Adic -Integrals

    Directory of Open Access Journals (Sweden)

    Jang Lee-Chae

    2008-01-01

    Full Text Available By using -adic -integrals on , we define multiple twisted -Euler numbers and polynomials. We also find Witt's type formula for multiple twisted -Euler numbers and discuss some characterizations of multiple twisted -Euler Zeta functions. In particular, we construct multiple twisted Barnes' type -Euler polynomials and multiple twisted Barnes' type -Euler Zeta functions. Finally, we define multiple twisted Dirichlet's type -Euler numbers and polynomials, and give Witt's type formula for them.

  3. A Computational Study of BVI Noise Reduction Using Active Twist Control

    Science.gov (United States)

    Fogarty, David E.; Wilbur, Matthew L.; Sekula, Martin K.

    2010-01-01

    The results of a computational study examining the effects of active-twist control on blade-vortex interaction (BVI) noise using the Apache Active Twist Rotor are presented. The primary goal of this activity is to reduce BVI noise during a low-speed descent flight condition using active-twist control. Rotor aeroelastic behavior was modeled using the Comprehensive Analytical Model of Rotorcraft Aerodynamics and Dynamics code and the rotor noise was predicted using the acoustics code PSU-WOPWOP. The accuracy of the analysis was validated through comparisons with experimental acoustic data for the first generation Active Twist Rotor at an advance ratio of mu=0.14. The application of active-twist to the main rotor blade system consisted of harmonic actuation frequencies ranging from 2P to 5P, control phase angles from 0' to 360 , and tip-twist amplitudes ranging from 0.5 to 4.0 . The acoustic analysis was conducted for a single low-speed flight condition of advance ratio =0.14 and shaft angle-of-attack, c^=+6 , with BVI noise levels predicted on a flat plane of observers located 1.1 rotor diameters beneath the rotor. The results indicated reductions of up to 11dB in BVI noise using 1.25 tip-twist amplitude with negligible effects on 4P vertical hub shear.

  4. Large N reduction on a twisted torus

    CERN Document Server

    González-Arroyo, A; Neuberger, H

    2005-01-01

    We consider SU(N) lattice gauge theory at infinite N defined on a torus with a CP invariant twist. Massless fermions are incorporated in an elegant way, while keeping them quenched. We present some numerical results which suggest that twisting can make numerical simulations of planar QCD more efficient.

  5. Stress effects in twisted highly birefringent fibers

    Science.gov (United States)

    Wolinski, Tomasz R.

    1994-03-01

    Hydrostatic pressure and uniaxial longitudinal strain effects in twisted highly birefringent optical fibers have been investigated from the point of the Marcuse mode-coupling theory. The problem is analyzed in terms of local normal modes of the ideal fiber and in the limit of weak twist, where large linear birefringence dominates over twist effect, and therefore twist coupling between local modes is not effective. The authors present the results of birefringence measurements in highly birefringent bow-tie fibers influenced simultaneously by hydrostatic pressure up to 100 MPa and twisting the result for highly birefringent elliptical-core fibers influenced by uniaxial longitudinal strain up to 4000 (mu) (epsilon) and twisting effect. The birefringence measurement method is based on twist-induced effects and has been successfully applied in a stress environment. The experiment was conducted with a specially designed stress generating device that makes it possible to simultaneously generate various mechanical perturbations such as hydrostatic and radial pressure, axial strain and twist, allowing study of their influence on mode propagation in optical fibers. A comparison with theoretical results as well as with pervious experimental data on stress influence on the beat length parameter in highly birefringent fibers is also provided.

  6. Decay constants from twisted mass QCD

    CERN Document Server

    Dimopoulos, P; Michael, C; Simula, S; Urbach, C

    2008-01-01

    We present results for chiral extrapolations of the mass and decay constants of the rho meson. The data sets used are the nf=2 unquenched gauge configurations generated with twisted mass fermions by the European Twisted Mass Collaboration. We describe a calculation of three decay constants in charmonium and explain why they are required.

  7. Twisting theory for weak Hopf algebras

    Institute of Scientific and Technical Information of China (English)

    CHEN Ju-zhen; ZHANG Yan; WANG Shuan-hong

    2008-01-01

    The main aim of this paper is to study the twisting theory of weak Hopf algebras and give an equivalence between the (braided) monoidal categories of weak Hopf bimodules over the original and the twisted weak Hopf algebra to generalize the result from Oeckl (2000).

  8. Do twisted laser beams evoke nuclear hyperpolarization?

    Science.gov (United States)

    Schmidt, A. B.; Andrews, D. L.; Rohrbach, A.; Gohn-Kreuz, C.; Shatokhin, V. N.; Kiselev, V. G.; Hennig, J.; von Elverfeldt, D.; Hövener, J.-B.

    2016-07-01

    The hyperpolarization of nuclear spins promises great advances in chemical analysis and medical diagnosis by substantially increasing the sensitivity of nuclear magnetic resonance (NMR). Current methods to produce a hyperpolarized sample, however, are arduous, time-consuming or costly and require elaborate equipment. Recently, a much simpler approach was introduced that holds the potential, if harnessed appropriately, to revolutionize the production of hyperpolarized spins. It was reported that high levels of hyperpolarization in nuclear spins can be created by irradiation with a laser beam carrying orbital angular momentum (twisted light). Aside from these initial reports however, no further experimental verification has been presented. In addition, this effect has so far evaded a critical theoretical examination. In this contribution, we present the first independent attempt to reproduce the effect. We exposed a sample of immersion oil or a fluorocarbon liquid that was placed within a low-field NMR spectrometer to Laguerre-Gaussian and Bessel laser beams at a wavelength of 514.5 nm and various topological charges. We acquired 1H and 19F NMR free induction decay data, either during or alternating with the irradiation that was parallel to B0. We observed an irregular increase in NMR signal in experiments where the sample was exposed to beams with higher values of the topological charge. However, at no time did the effect reach statistical significance of 95%. Given the measured sensitivity of our setup, we estimate that a possible effect did not exceed a hyperpolarization (at 5 mT) of 0.14-6%, depending on the assumed hyperpolarized volume. It should be noted though, that there were some differences between our setup and the previous implementation of the experiment, which may have inhibited the full incidence of this effect. To approach a theoretical description of this effect, we considered the interaction of an electron with a plane wave, which is known to be

  9. N=4 Twisted Superspace from Dirac-Kahler Twist and Off-shell SUSY Invariant Actions in Four Dimensions

    CERN Document Server

    Kato, J; Miyake, A; Kato, Junji; Kawamoto, Noboru; Miyake, Akiko

    2005-01-01

    We propose N=4 twisted superspace formalism in four dimensions by introducing Dirac-Kahler twist. In addition to the BRST charge as a scalar counter part of twisted supercharge we find vector and tensor twisted supercharges. By introducing twisted chiral superfield we explicitly construct off-shell twisted N=4 SUSY invariant action. We can propose variety of supergauge invariant actions by introducing twisted vector superfield. We may, however, need to find further constraints to identify twisted N=4 super Yang-Mills action. We propose a superconnection formalism of twisted superspace where constraints play a crucial role. It turns out that N=4 superalgebra of Dirac-Kahler twist can be decomposed into N=2 sectors. We can then construct twisted N=2 super Yang-Mills actions by the superconnection formalism of twisted superspace in two and four dimensions.

  10. Superlattice-Induced Insulating States and Valley-Protected Orbits in Twisted Bilayer Graphene

    Science.gov (United States)

    Cao, Y.; Luo, J. Y.; Fatemi, V.; Fang, S.; Sanchez-Yamagishi, J. D.; Watanabe, K.; Taniguchi, T.; Kaxiras, E.; Jarillo-Herrero, P.

    2016-09-01

    Twisted bilayer graphene (TBLG) is one of the simplest van der Waals heterostructures, yet it yields a complex electronic system with intricate interplay between moiré physics and interlayer hybridization effects. We report on electronic transport measurements of high mobility small angle TBLG devices showing clear evidence for insulating states at the superlattice band edges, with thermal activation gaps several times larger than theoretically predicted. Moreover, Shubnikov-de Haas oscillations and tight binding calculations reveal that the band structure consists of two intersecting Fermi contours whose crossing points are effectively unhybridized. We attribute this to exponentially suppressed interlayer hopping amplitudes for momentum transfers larger than the moiré wave vector.

  11. Hidden Beauty in Twisted Viking Neck Rings

    CERN Document Server

    Olsen, Kasper

    2010-01-01

    Many hoards found in Ireland, Scotland, Orkney Islands, and Scandinavia demonstrate the vikings ability to fabricate beautiful arm and neck rings of twisted silver and gold rods. Characteristic for such rings is the uniform appearance of the twisted pattern along the length of the arm ring, as well as from one arm ring to another, also when found at distant geographical locations. How can the appearance of the twisted wires be so perfectly repetitive? We demonstrate that the answer is that the vikings utilized a self-forming motif: The pattern arises from a twisting of the wires to a maximally rotated configuration. That is why the twist patterns in these arm and neck rings are beautiful, repetitive, and universal.

  12. Applying manifold learning to plotting approximate contour trees.

    Science.gov (United States)

    Takahashi, Shigeo; Fujishiro, Issei; Okada, Masato

    2009-01-01

    A contour tree is a powerful tool for delineating the topological evolution of isosurfaces of a single-valued function, and thus has been frequently used as a means of extracting features from volumes and their time-varying behaviors. Several sophisticated algorithms have been proposed for constructing contour trees while they often complicate the software implementation especially for higher-dimensional cases such as time-varying volumes. This paper presents a simple yet effective approach to plotting in 3D space, approximate contour trees from a set of scattered samples embedded in the high-dimensional space. Our main idea is to take advantage of manifold learning so that we can elongate the distribution of high-dimensional data samples to embed it into a low-dimensional space while respecting its local proximity of sample points. The contribution of this paper lies in the introduction of new distance metrics to manifold learning, which allows us to reformulate existing algorithms as a variant of currently available dimensionality reduction scheme. Efficient reduction of data sizes together with segmentation capability is also developed to equip our approach with a coarse-to-fine analysis even for large-scale datasets. Examples are provided to demonstrate that our proposed scheme can successfully traverse the features of volumes and their temporal behaviors through the constructed contour trees.

  13. The effect of bending and twisting on the stiffness and strength of the 3.5 SOP implant.

    Science.gov (United States)

    Ness, M G

    2009-01-01

    Locking plates are becoming increasingly popular in veterinary orthopaedics. The SOP is a novel locking plate system, which can be contoured with 6 degrees of freedom and which utilises standard bone screws. The purpose of this work was to investigate the mechanical consequences of contouring the 3.5 SOP plate to support the formulation of clinical guidelines. The implants were loaded in four point bending using an industry standard protocol. The uncontoured SOP was found to be significantly stiffer and stronger than the uncontoured 3.5 DCP. Bending, and to a lesser extent, twisting, diminished the SOP's stiffness and strength but the contoured SOP remained at least as stiff and strong as the untouched DCP.

  14. Twisted spacetime in Einstein gravity

    CERN Document Server

    Zhang, Hongsheng

    2016-01-01

    We find a vacuum stationary twisted solution in four-dimensional Einstein gravity. Its frame dragging angular velocities are antisymmetric with respect to the equatorial plane. It possesses a symmetry of joint inversion of time and parity with respect to the equatorial plane. Its Arnowitt-Deser-Misner (ADM) mass and angular momentum are zero. It is curved but regular all over the manifold. Its Komar mass and Komar angular momentum are also zero. Its infinite red-shift surface coincides with its event horizon, since the event horizon does not rotate. Furthermore we extend this solution to the massive case, and find some similar properties. This solution is a stationary axisymmetric solution, but not Kerr. It explicitly proves that pure Einstein gravity permits different rotational mode other than Kerr. Our results demonstrate that the Einstein theory may have much more rich structures than what we ever imagine.

  15. Twisting cracks in Bouligand structures.

    Science.gov (United States)

    Suksangpanya, Nobphadon; Yaraghi, Nicholas A; Kisailus, David; Zavattieri, Pablo

    2017-06-10

    The Bouligand structure, which is found in many biological materials, is a hierarchical architecture that features uniaxial fiber layers assembled periodically into a helicoidal pattern. Many studies have highlighted the high damage-resistant performance of natural and biomimetic Bouligand structures. One particular species that utilizes the Bouligand structure to achieve outstanding mechanical performance is the smashing Mantis Shrimp, Odontodactylus Scyllarus (or stomatopod). The mantis shrimp generates high speed, high acceleration blows using its raptorial appendage to defeat highly armored preys. The load-bearing part of this appendage, the dactyl club, contains an interior region [16] that consists of a Bouligand structure. This region is capable of developing a significant amount of nested twisting microcracks without exhibiting catastrophic failure. The development and propagation of these microcracks are a source of energy dissipation and stress relaxation that ultimately contributes to the remarkable damage tolerance properties of the dactyl club. We develop a theoretical model to provide additional insights into the local stress intensity factors at the crack front of twisting cracks formed within the Bouligand structure. Our results reveal that changes in the local fracture mode at the crack front leads to a reduction of the local strain energy release rate, hence, increasing the necessary applied energy release rate to propagate the crack, which is quantified by the local toughening factor. Ancillary 3D simulations of the asymptotic crack front field were carried out using a J-integral to validate the theoretical values of the energy release rate and the local stress intensity factors. Copyright © 2017 Elsevier Ltd. All rights reserved.

  16. Comments on the Blumlein-Bottcher determination of higher twist corrections to the nucleon spin structure function g_1

    CERN Document Server

    Leader, Elliot; Stamenov, Dimiter B

    2010-01-01

    In a recent analysis of the world data on polarized DIS, Blumlein and Bottcher conclude that there is no evidence for higher twist contributions, in contrast to the claim of the LSS group, who find evidence for significant higher twist effects. We explain the origin of the apparent contradiction between these results.

  17. Contours--Offshore of Santa Barbara, California

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — This part of SIM 3281 presents data for the bathymetric contours for several seafloor maps (see sheets 1, 2, 3, 7, 10, SIM 3281) of the Offshore of Santa Barbara...

  18. Contours--Offshore Coal Oil Point, California

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — This part of SIM 3302 presents bathymetric contours for several seafloor maps of Offshore Coal Oil Point, California (vector data file is included in...

  19. Transgressive Contours--Bolinas to Pescadero, California

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — This part of DS 781 presents data for the transgressive contours for the Bolinas to Pescadero, California, region. The vector file is included in...

  20. Contours-Offshore of Bodega Head, California

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — This part of DS 781 presents data for the bathymetric contours for several seafloor maps of the Offshore of Bodega Head map area, California. The vector data file is...

  1. Contours--Offshore of Pacifica, California

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — This part of DS 781 presents data for the bathymetric contours for several seafloor maps of the Offshore of Pacifica map area, California. The vector data file is...

  2. Contours--Drakes Bay and Vicinity, California

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — This part of DS 781 presents data for the bathymetric contours for several seafloor maps of the Drakes Bay and Vicinity map area, California. The vector data file is...

  3. Contours--Monterey Canyon and Vicinity, California

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — This part of DS 781 presents bathymetric contours for several seafloor maps of the Monterey Canyon and Vicinity map area, California. The raster data file is...

  4. An Active Contour for Range Image Segmentation

    OpenAIRE

    Khaldi Amine; Merouani Hayet Farida

    2012-01-01

    In this paper a new classification of range image segmentation method is proposed according to the criterion of homogeneity which obeys the segmentation, then, a deformable model-type active contour “Snake” is applied to segment range images.

  5. Contours--Offshore Refugio Beach, California

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — This part of SIM 3319 presents bathymetric contours for several seafloor maps of Offshore Refugio Beach, California (vector data file is included in...

  6. Contours-Offshore of Bodega Head, California

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — This part of DS 781 presents data for the bathymetric contours for several seafloor maps of the Offshore of Bodega Head map area, California. The vector data file is...

  7. Water-table contours of Nevada

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — This data set consists of water-table contours for Nevada. These data were created as part of an effort to provide statewide information on water table and depth to...

  8. Contours--Offshore of Pacifica, California

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — This part of DS 781 presents data for the bathymetric contours for several seafloor maps of the Offshore of Pacifica map area, California. The vector data file is...

  9. Contours--Offshore of Fort Ross, California

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — This part of DS 781 presents data for the bathymetric contours for several seafloor maps of the Offshore of Fort Ross map area, California. The vector data file is...

  10. Contours Offshore of Tomales Point, California

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — This part of DS 781 presents data for the bathymetric contours for several seafloor maps of the Offshore of Tomales Point map area, California. The vector data file...

  11. Contours--Offshore Santa Cruz, California

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — This part of DS 781 presents data for the bathymetric contours for several seafloor maps of the Offshore Santa Cruz map area, California. The vector data file is...

  12. Contours--Offshore Pigeon Point, California

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — This part of DS 781 presents data for the bathymetric contours for several seafloor maps of the Offshore Pigeon Point map area, California. The vector data file is...

  13. Contours--Offshore of Fort Ross, California

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — This part of DS 781 presents data for the bathymetric contours for several seafloor maps of the Offshore of Fort Ross map area, California. The vector data file is...

  14. Contours--Offshore Scott Creek, California

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — This part of DS 781 presents data for the bathymetric contours for several seafloor maps of the Offshore Scott Creek map area, California. The vector data file is...

  15. Contours--Offshore of San Francisco, California

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — This part of DS 781 presents data for the bathymetric contours for several seafloor maps of the Offshore of San Francisco map area, California. The vector data file...

  16. Transgressive Contours--Bolinas to Pescadero, California

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — This part of DS 781 presents data for the transgressive contours for the Bolinas to Pescadero, California, region. The vector file is included in...

  17. Contours--Offshore Scott Creek, California

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — This part of DS 781 presents data for the bathymetric contours for several seafloor maps of the Offshore Scott Creek map area, California. The vector data file is...

  18. Contours--Offshore Santa Cruz, California

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — This part of DS 781 presents data for the bathymetric contours for several seafloor maps of the Offshore Santa Cruz map area, California. The vector data file is...

  19. Contours--Monterey Canyon and Vicinity, California

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — This part of DS 781 presents bathymetric contours for several seafloor maps of the Monterey Canyon and Vicinity map area, California. The raster data file is...

  20. DYNAMICS OF STRONGLY TWISTED RELATIVISTIC MAGNETOSPHERES

    Energy Technology Data Exchange (ETDEWEB)

    Parfrey, Kyle [Astronomy Department, Columbia University, 550 West 120th Street, New York, NY 10027 (United States); Beloborodov, Andrei M.; Hui, Lam, E-mail: parfrey@astro.princeton.edu [Physics Department and Columbia Astrophysics Laboratory, Columbia University, 538 West 120th Street, New York, NY 10027 (United States)

    2013-09-10

    Magnetar magnetospheres are believed to be strongly twisted due to shearing of the stellar crust by internal magnetic stresses. We present time-dependent axisymmetric simulations showing in detail the evolution of relativistic force-free magnetospheres subjected to slow twisting through large angles. When the twist amplitude is small, the magnetosphere moves quasi-statically through a sequence of equilibria of increasing free energy. At some twist amplitude the magnetosphere becomes tearing-mode unstable to forming a resistive current sheet, initiating large-scale magnetic reconnection in which a significant fraction of the magnetic free energy can be dissipated. This ''critical'' twist angle is insensitive to the resistive length scale. Rapid shearing temporarily stabilizes the magnetosphere beyond the critical angle, allowing the magnetosphere of a rapidly differentially rotating star to store and dissipate more free energy. In addition to these effects, shearing the surface of a rotating star increases the spindown torque applied to the star. If shearing is much slower than rotation, the resulting spikes in spindown rate can occur on timescales anywhere from the long twisting timescale to the stellar spin period or shorter, depending both on the stellar shear distribution and the existing distribution of magnetospheric twists. A model in which energy is stored in the magnetosphere and released by a magnetospheric instability therefore predicts large changes in the measured spindown rate before soft gamma repeater giant flares.

  1. Expert Consensus Contouring Guidelines for Intensity Modulated Radiation Therapy in Esophageal and Gastroesophageal Junction Cancer

    Energy Technology Data Exchange (ETDEWEB)

    Wu, Abraham J., E-mail: wua@mskcc.org [Memorial Sloan-Kettering Cancer Center, New York, New York (United States); Bosch, Walter R. [Washington University, St. Louis, Missouri (United States); Chang, Daniel T. [Stanford Cancer Institute, Stanford, California (United States); Hong, Theodore S. [Massachusetts General Hospital, Boston, Massachusetts (United States); Jabbour, Salma K. [Rutgers Cancer Institute of New Jersey, New Brunswick, New Jersey (United States); Kleinberg, Lawrence R. [Johns Hopkins Medical Center, Baltimore, Maryland (United States); Mamon, Harvey J. [Brigham and Women' s Hospital, Boston, Massachusetts (United States); Thomas, Charles R. [Knight Cancer Institute, Oregon Health & Sciences University, Portland, Oregon (United States); Goodman, Karyn A. [Memorial Sloan-Kettering Cancer Center, New York, New York (United States)

    2015-07-15

    Purpose/Objective(s): Current guidelines for esophageal cancer contouring are derived from traditional 2-dimensional fields based on bony landmarks, and they do not provide sufficient anatomic detail to ensure consistent contouring for more conformal radiation therapy techniques such as intensity modulated radiation therapy (IMRT). Therefore, we convened an expert panel with the specific aim to derive contouring guidelines and generate an atlas for the clinical target volume (CTV) in esophageal or gastroesophageal junction (GEJ) cancer. Methods and Materials: Eight expert academically based gastrointestinal radiation oncologists participated. Three sample cases were chosen: a GEJ cancer, a distal esophageal cancer, and a mid-upper esophageal cancer. Uniform computed tomographic (CT) simulation datasets and accompanying diagnostic positron emission tomographic/CT images were distributed to each expert, and the expert was instructed to generate gross tumor volume (GTV) and CTV contours for each case. All contours were aggregated and subjected to quantitative analysis to assess the degree of concordance between experts and to generate draft consensus contours. The panel then refined these contours to generate the contouring atlas. Results: The κ statistics indicated substantial agreement between panelists for each of the 3 test cases. A consensus CTV atlas was generated for the 3 test cases, each representing common anatomic presentations of esophageal cancer. The panel agreed on guidelines and principles to facilitate the generalizability of the atlas to individual cases. Conclusions: This expert panel successfully reached agreement on contouring guidelines for esophageal and GEJ IMRT and generated a reference CTV atlas. This atlas will serve as a reference for IMRT contours for clinical practice and prospective trial design. Subsequent patterns of failure analyses of clinical datasets using these guidelines may require modification in the future.

  2. Expert consensus contouring guidelines for IMRT in esophageal and gastroesophageal junction cancer

    Science.gov (United States)

    Wu, Abraham J.; Bosch, Walter R.; Chang, Daniel T.; Hong, Theodore S.; Jabbour, Salma K.; Kleinberg, Lawrence R.; Mamon, Harvey J.; Thomas, Charles R.; Goodman, Karyn A.

    2015-01-01

    Purpose/Objective(s) Current guidelines for esophageal cancer contouring are derived from traditional two-dimensional fields based on bony landmarks, and do not provide sufficient anatomical detail to ensure consistent contouring for more conformal radiotherapy techniques such as intensity-modulated radiation therapy (IMRT). Therefore, we convened an expert panel with the specific aim to derive contouring guidelines and generate an atlas for the clinical target volume (CTV) in esophageal or gastroesophageal junction (GEJ) cancer. Methods and Materials Eight expert academically-based gastrointestinal radiation oncologists participated. Three sample cases were chosen: a GEJ cancer, a distal esophageal cancer, and a mid-upper esophageal cancer. Uniform CT simulation datasets and an accompanying diagnostic PET-CT were distributed to each expert, and he/she was instructed to generate gross tumor volume (GTV) and CTV contours for each case. All contours were aggregated and subjected to quantitative analysis to assess the degree of concordance between experts and generate draft consensus contours. The panel then refined these contours to generate the contouring atlas. Results Kappa statistics indicated substantial agreement between panelists for each of the three test cases. A consensus CTV atlas was generated for the three test cases, each representing common anatomic presentations of esophageal cancer. The panel agreed on guidelines and principles to facilitate the generalizability of the atlas to individual cases. Conclusions This expert panel successfully reached agreement on contouring guidelines for esophageal and GEJ IMRT and generated a reference CTV atlas. This atlas will serve as a reference for IMRT contours for clinical practice and prospective trial design. Subsequent patterns of failure analyses of clinical datasets utilizing these guidelines may require modification in the future. PMID:26104943

  3. Decoupled active contour (DAC) for boundary detection.

    Science.gov (United States)

    Mishra, Akshaya Kumar; Fieguth, Paul W; Clausi, David A

    2011-02-01

    The accurate detection of object boundaries via active contours is an ongoing research topic in computer vision. Most active contours converge toward some desired contour by minimizing a sum of internal (prior) and external (image measurement) energy terms. Such an approach is elegant, but suffers from a slow convergence rate and frequently misconverges in the presence of noise or complex contours. To address these limitations, a decoupled active contour (DAC) is developed which applies the two energy terms separately. Essentially, the DAC consists of a measurement update step, employing a Hidden Markov Model (HMM) and Viterbi search, and then a separate prior step, which modifies the updated curve based on the relative strengths of the measurement uncertainty and the nonstationary prior. By separating the measurement and prior steps, the algorithm is less likely to misconverge; furthermore, the use of a Viterbi optimizer allows the method to converge far more rapidly than energy-based iterative solvers. The results clearly demonstrate that the proposed approach is robust to noise, can capture regions of very high curvature, and exhibits limited dependence on contour initialization or parameter settings. Compared to five other published methods and across many image sets, the DAC is found to be faster with better or comparable segmentation accuracy.

  4. Isolating contour information from arbitrary images

    Science.gov (United States)

    Jobson, Daniel J.

    1989-01-01

    Aspects of natural vision (physiological and perceptual) serve as a basis for attempting the development of a general processing scheme for contour extraction. Contour information is assumed to be central to visual recognition skills. While the scheme must be regarded as highly preliminary, initial results do compare favorably with the visual perception of structure. The scheme pays special attention to the construction of a smallest scale circular difference-of-Gaussian (DOG) convolution, calibration of multiscale edge detection thresholds with the visual perception of grayscale boundaries, and contour/texture discrimination methods derived from fundamental assumptions of connectivity and the characteristics of printed text. Contour information is required to fall between a minimum connectivity limit and maximum regional spatial density limit at each scale. Results support the idea that contour information, in images possessing good image quality, is (centered at about 10 cyc/deg and 30 cyc/deg). Further, lower spatial frequency channels appear to play a major role only in contour extraction from images with serious global image defects.

  5. Perception of illusory contours enhanced in motion

    Institute of Scientific and Technical Information of China (English)

    倪睿; 王志宏; 吴新年; 汪云九; 李东光

    2003-01-01

    Investigation on illusory contours is important for understanding the mechanisms un-derlying the object recognition of human visual system. Numerous researches have shown that illusory contours formed in motion and stereopsis are generated by the unmatched features. Here we conduct three psychophysical experiments to test if Kanizsa illusory contours are also caused by unmatched information. Different types of motion (including horizontal translation, radial ex-panding and shrinking) are utilized in the experiments. The results show that no matter under what kind of motion, when figures or background move separately illusory contours are perceived stronger, and there is no significant difference between the perceived strength in these two types of motion. However, no such enhancement of perceived strength is found when figures and background move together. It is found that the strengthened unmatched features generate the enhancement effect of illusory contour perception in motion. Thus the results suggest that the process of unmatched information in visual system is a critical step in the formation of illusory contours.

  6. Diffusion tensor driven contour closing for cell microinjection targeting.

    Science.gov (United States)

    Becattini, Gabriele; Mattos, Leonardo S; Caldwell, Darwin G

    2010-01-01

    This article introduces a novel approach to robust automatic detection of unstained living cells in bright-field (BF) microscope images with the goal of producing a target list for an automated microinjection system. The overall image analysis process is described and includes: preprocessing, ridge enhancement, image segmentation, shape analysis and injection point definition. The developed algorithm implements a new version of anisotropic contour completion (ACC) based on the partial differential equation (PDE) for heat diffusion which improves the cell segmentation process by elongating the edges only along their tangent direction. The developed ACC algorithm is equivalent to a dilation of the binary edge image with a continuous elliptic structural element that takes into account local orientation of the contours preventing extension towards normal direction. Experiments carried out on real images of 10 to 50 microm CHO-K1 adherent cells show a remarkable reliability in the algorithm along with up to 85% success for cell detection and injection point definition.

  7. Novel Properties of Twisted-Photon Absorption

    CERN Document Server

    Afanasev, Andrei; Mukherjee, Asmita

    2014-01-01

    We discuss novel features of twisted-photon absorption both by atoms and by micro-particles. First, we extend the treatment of atomic photoexcitation by twisted photons to include atomic recoil, derive generalized quantum selection rules and consider phenomena of forbidden atomic transitions. Second, we analyze the radiation pressure from twisted-photon beams on micro- and nano-sized particles and observe that for particular conditions the pressure is negative in a small area near the beam axis. A central part of the beam therefore acts as a "tractor beam".

  8. Twisted spectral geometry for the standard model

    Science.gov (United States)

    Martinetti, Pierre

    2015-07-01

    In noncommutative geometry, the spectral triple of a manifold does not generate bosonic fields, for fluctuations of the Dirac operator vanish. A Connes-Moscovici twist forces the commutative algebra to be multiplied by matrices. Keeping the space of spinors untouched, twisted-fluctuations then yield perturbations of the spin connection. Applied to the spectral triple of the Standard Model, a similar twist yields the scalar field needed to stabilize the vacuum and to make the computation of the Higgs mass compatible with its experimental value.

  9. Spin, twist and hadron structure in deep inelastic processes

    CERN Document Server

    Jaffe, R L

    1997-01-01

    These notes provide an introduction to polarization effects in deep inelastic processes in QCD. We emphasize recent work on transverse asymmetries, subdominant effects, and the role of polarization in fragmentation and in purely hadronic processes. After a review of kinematics and some basic tools of short distance analysis, we study the twist, helicity, chirality and transversity dependence of a variety of high energy processes sensitive to the quark and gluon substructure of hadrons.

  10. Effects of Contoured Pallets on AMC Mission Efficiency

    Science.gov (United States)

    2011-06-01

    airlines. It postulated that national security would benefit from keeping commercial airlines as a viable source of airlift (Donovan, 2011). After the...Research Project, AFIT/ GMO /ENS/04I-01, Air Force Institute of Technology, Wright-Patterson AFB, OH McNabb, Duncan J. (2009). Statement of General Duncan...analysis of the benefits in producing more contoured pallets AMC and USTRANSCOM can increase the efficiency of channel airlift while boosting civilian

  11. Twist1 Is Essential for Tooth Morphogenesis and Odontoblast Differentiation.

    Science.gov (United States)

    Meng, Tian; Huang, Yanyu; Wang, Suzhen; Zhang, Hua; Dechow, Paul C; Wang, Xiaofang; Qin, Chunlin; Shi, Bing; D'Souza, Rena N; Lu, Yongbo

    2015-12-04

    Twist1 is a basic helix-loop-helix-containing transcription factor that is expressed in the dental mesenchyme during the early stages of tooth development. To better delineate its roles in tooth development, we generated Twist1 conditional knockout embryos (Twist2(Cre) (/+);Twist1(fl/fl)) by breeding Twist1 floxed mice (Twist1(fl/fl)) with Twist2-Cre recombinase knockin mice (Twist2(Cre) (/+)). The Twist2(Cre) (/+);Twist1(fl/fl) embryos formed smaller tooth germs and abnormal cusps during early tooth morphogenesis. Molecular and histological analyses showed that the developing molars of the Twist2(Cre) (/+);Twist1(fl/fl) embryos had reduced cell proliferation and expression of fibroblast growth factors 3, 4, 9, and 10 and FGF receptors 1 and 2 in the dental epithelium and mesenchyme. In addition, 3-week-old renal capsular transplants of embryonic day 18.5 Twist2(Cre) (/+);Twist1(fl/fl) molars showed malformed crowns and cusps with defective crown dentin and enamel. Immunohistochemical analyses revealed that the implanted mutant molars had defects in odontoblast differentiation and delayed ameloblast differentiation. Furthermore, in vitro ChIP assays demonstrated that Twist1 was able to bind to a specific region of the Fgf10 promoter. In conclusion, our findings suggest that Twist1 plays crucial roles in regulating tooth development and that it may exert its functions through the FGF signaling pathway. © 2015 by The American Society for Biochemistry and Molecular Biology, Inc.

  12. Investigation of Propagation Characteristics of Twisted Hollow Waveguides for Particle Accelerator Applications

    Energy Technology Data Exchange (ETDEWEB)

    Wilson, Joshua Lee [Univ. of Tennessee, Knoxville, TN (United States)

    2008-12-01

    A new class of accelerating structures employing a uniformly twisted waveguide is investigated. Twisted waveguides of various cross-sectional geometries are considered and analyzed. It is shown that such a twisted waveguide can support waves that travel at a speed slower than the speed of light c. The slow-wave properties of twisted structures are of interest because these slow-wave electromagnetic fields can be used in applications such as electron traveling wave tubes and linear particle accelerators. Since there is no exact closed form solution for the electromagnetic fields within a twisted waveguide or cavity, several previously proposed approximate methods are examined, and more effcient approaches are developed. It is found that the existing perturbation theory methods yield adequate results for slowly twisted structures; however, our efforts here are geared toward analyzing rapidly twisted structures using modifed finite difference methods specially suited for twisted structures. Although the method can handle general twisted structures, three particular cross sections are selected as representative cases for careful analysis. First, a slowly twisted rectangular cavity is analyzed as a reference case. This is because its shape is simple and perturbation theory already gives a good approximate solution for such slow twists rates. Secondly, a symmetrically notched circular cross section is investigated, since its longitudinal cross section is comparable to the well known disk-loaded cavity (used in many practical accelerator designs, including SLAC). Finally, a "dumbbell" shaped cross section is analyzed because of its similarity to the well-known TESLA-type accelerating cavity, which is of great importance because of its wide acceptance as a superconducting cavity. To validate the results of the developed theory and our extensive simulations, the newly developed numerical models are compared to commercial codes. Also, several prototypes are developed

  13. Topological hypermultiplet on N=2 twisted superspace in four dimensions

    CERN Document Server

    Kato, J; Kato, Junji; Miyake, Akiko

    2005-01-01

    We propose a N=2 twisted superspace formalism with a central charge in four dimensions by introducing a Dirac-K\\"ahler twist. Using this formalism, we construct a twisted hypermultiplet action and find an explicit form of fermionic scalar, vector and tensor transformations. We construct a off-shell Donaldson-Witten theory coupled to the twisted hypermultiplet. We show that this action possesses N=4 twisted supersymmetry at on-shell level. It turns out that four-dimensional Dirac-K\\"ahler twist is equivalent to the Marcus's twist.

  14. Probing the interlayer coupling of twisted bilayer MoS2 using photoluminescence spectroscopy.

    Science.gov (United States)

    Huang, Shengxi; Ling, Xi; Liang, Liangbo; Kong, Jing; Terrones, Humberto; Meunier, Vincent; Dresselhaus, Mildred S

    2014-10-08

    Two-dimensional molybdenum disulfide (MoS2) is a promising material for optoelectronic devices due to its strong photoluminescence emission. In this work, the photoluminescence of twisted bilayer MoS2 is investigated, revealing a tunability of the interlayer coupling of bilayer MoS2. It is found that the photoluminescence intensity ratio of the trion and exciton reaches its maximum value for the twisted angle 0° or 60°, while for the twisted angle 30° or 90° the situation is the opposite. This is mainly attributed to the change of the trion binding energy. The first-principles density functional theory analysis further confirms the change of the interlayer coupling with the twisted angle, which interprets our experimental results.

  15. Transmission properties of cryogenic twisted pair filters

    Energy Technology Data Exchange (ETDEWEB)

    Song, Woon; Rehman, Mushtaq; Chong, Yonuk [Korea Research Institute of Standards and Science, Daejeon (Korea, Republic of); Ryu, Sangwan [Chonnam National University, Gwangju (Korea, Republic of)

    2010-12-15

    We fabricated a cryogenic low pass filter that consists of twisted pairs of manganin wires wrapped in copper tape and measured its transmission characteristics at frequencies up to 18 GHz. The dependence of the microwave transmission characteristics on the filter length was studied, which showed that a filter of length 1.0 m had a 70-dB attenuation at 1 GHz. We also studied the dependence of common- and differential-mode transmission on the number of twists per unit length and found that the number of twists per unit length affects differential-mode transmission but not common-mode transmission. Because the shielded twisted pair filter is more compact than a conventional copper powder filter, it can solve the space and thermal load issues when many cables are required for precision electronic transport experiments at low temperatures.

  16. Mutations in the human TWIST gene.

    Science.gov (United States)

    Gripp, K W; Zackai, E H; Stolle, C A

    2000-01-01

    Saethre-Chotzen syndrome is a relatively common craniosynostosis disorder with autosomal dominant inheritance. Mutations in the TWIST gene have been identified in patients with Saethre-Chotzen syndrome. The TWIST gene product is a transcription factor with DNA binding and helix-loop-helix domains. Numerous missense and nonsense mutations cluster in the functional domains, without any apparent mutational hot spot. Two novel point mutations and one novel polymorphism are included in this review. Large deletions including the TWIST gene have been identified in some patients with learning disabilities or mental retardation, which are not typically part of the Saethre-Chotzen syndrome. Comprehensive studies in patients with the clinical diagnosis of Saethre-Chotzen syndrome have demonstrated a TWIST gene abnormality in about 80%, up to 37% of which may be large deletions [Johnson et al., 1998]. The gene deletions and numerous nonsense mutations are suggestive of haploinsufficiency as the disease-causing mechanism. No genotype phenotype correlation was apparent.

  17. Observation of subluminal twisted light in vacuum

    CERN Document Server

    Bouchard, Frédéric; Mand, Harjaspreet; Boyd, Robert W; Karimi, Ebrahim

    2015-01-01

    Einstein's theory of relativity establishes the speed of light in vacuum, c, as a fundamental constant. However, the speed of light pulses can be altered significantly in dispersive materials. While significant control can be exerted over the speed of light in such media, no experimental demonstration of altered light speeds has hitherto been achieved in vacuum for ``twisted'' optical beams. We show that ``twisted'' light pulses exhibit subluminal velocities in vacuum, being slowed by 0.1\\% relative to c. This work does not challenge relativity theory, but experimentally supports a body of theoretical work on the counterintuitive vacuum group velocities of twisted pulses. These results are particularly important given recent interest in applications of twisted light to quantum information, communication and quantum key distribution.

  18. Twisted Vector Bundles on Pointed Nodal Curves

    Indian Academy of Sciences (India)

    Ivan Kausz

    2005-05-01

    Motivated by the quest for a good compactification of the moduli space of -bundles on a nodal curve we establish a striking relationship between Abramovich’s and Vistoli’s twisted bundles and Gieseker vector bundles.

  19. Gerbes and twisted orbifold quantum cohomology

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    In this paper,we construct an orbifold quantum cohomology twisted by a flat gerbe. Then we compute these invariants in the case of a smooth manifold and a discrete torsion on a global quotient orbifold.

  20. Deformed and twisted black holes with NUTs

    CERN Document Server

    Krtous, Pavel; Frolov, Valeri P; Kolar, Ivan

    2015-01-01

    We construct a new class of vacuum black hole solutions whose geometry is deformed and twisted by the presence of NUT charges. The solutions are obtained by `unspinning' the general Kerr-NUT-(A)dS spacetimes, effectively switching off some of their rotation parameters. The resulting geometry has a structure of warped space with the Kerr-like Lorentzian part warped to a Euclidean metric of deformed and/or twisted sphere, with the deformation and twist characterized by the `Euclidean NUT' parameters. In the absence of NUTs, the solution reduces to a well known Kerr-(A)dS black hole with several rotations switched off. New geometries inherit the original symmetry of the Kerr-NUT-(A)dS family, namely, they possess the full Killing tower of hidden and explicit symmetries. As expected, for vanishing NUT, twist, and deformation parameters, the symmetry is further enlarged.

  1. Gerbes and twisted orbifold quantum cohomology

    Institute of Scientific and Technical Information of China (English)

    PAN JianZhong; RUAN YongBin; YIN XiaoQin

    2008-01-01

    In this paper, we construct an orbifold quantum cohomology twisted by a flat gerbe.Then we compute these invariants in the case of a smooth manifold and a discrete torsion on a global quotient orbifold.

  2. Deformed and twisted black holes with NUTs

    Science.gov (United States)

    Krtouš, Pavel; Kubizňák, David; Frolov, Valeri P.; Kolář, Ivan

    2016-06-01

    We construct a new class of vacuum black hole solutions whose geometry is deformed and twisted by the presence of NUT charges. The solutions are obtained by ‘unspinning’ the general Kerr-NUT-(A)dS spacetimes, effectively switching off some of their rotation parameters. The resulting geometry has a structure of warped space with the Kerr-like Lorentzian part warped to a Euclidean metric of a deformed and/or twisted sphere, with the deformation and twist characterized by the ‘Euclidean NUT’ parameters. In the absence of NUTs, the solution reduces to a well known Kerr-(A)dS black hole with several rotations switched off. New geometries inherit the original symmetry of the Kerr-NUT-(A)dS family, namely, they possess the full Killing tower of hidden and explicit symmetries. As expected, for vanishing NUT, twist, and deformation parameters, the symmetry is further enlarged.

  3. Noncoalescence of sessile drops from different but miscible liquids: hydrodynamic analysis of the twin drop contour as a self-stabilizing traveling wave.

    Science.gov (United States)

    Karpitschka, Stefan; Riegler, Hans

    2012-08-10

    Capillarity always favors drop fusion. Nevertheless, sessile drops from different but completely miscible liquids often do not fuse instantaneously upon contact. Rather, intermediate noncoalescence is observed. Two separate drop bodies, connected by a thin liquid neck, move over the substrate. Supported by new experimental data, a thin film hydrodynamic analysis of this state is presented. Presumably advective and diffusive volume fluxes in the neck region establish a localized and temporarily stable surface tension gradient. This induces a local surface (Marangoni) flow that stabilizes a traveling wave, i.e., the observed moving twin drop configuration. The theoretical predictions are in excellent agreement with the experimental findings.

  4. Non-coalescence of sessile drops from different but miscible liquids: Hydrodynamic analysis of the twin drop contour as self stabilizing, traveling wave

    CERN Document Server

    Karpitschka, Stefan

    2015-01-01

    Capillarity always favors drop fusion. Nevertheless sessile drops from different but completely miscible liquids often do not fuse instantaneously upon contact. Rather, intermediate non-coalescence is observed. Two separate drop bodies, connected by a thin liquid neck move over the substrate. Supported by new experimental data a thin film hydrodynamic analysis of this state is presented. Presumably advective and diffusive volume fluxes in the neck region establish a localized and temporarily stable surface tension gradient. This induces a local surface (Marangoni) flow that stabilizes a traveling wave i.e., the observed moving twin drop configuration. The theoretical predictions are in excellent agreement with the experimental findings.

  5. Variation in contour and cancer of stomach

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Won Hong; Hwang, Seon Moon [Asan Medical Center, Asan (Korea, Republic of); Yoon, Kwon Ha [College of Medicine, Wonkwang Univ., Iksan (Korea, Republic of)

    1999-04-01

    There were four types of stomach contour included eutonic, hypotonic, steerhorn, and cascade. The aim of this study is to clarify relationship between incidence of stomach cancer and contour variation of the stomach. Double- contrast upper gastrointestinal study was performed in 1,546 patients, who had dyspepsia or other gastrointestinal tract symptoms. The radiographs were classified into the four types including eutonic, hypotonic, steerhorn, and cascade according to stomach contour in relation to body build. We also reviewed pathologic reports on endoscopic biopsy or surgical specimen. We studied the presence of relationship between incidence of stomach cancer and variation of stomach contour. We also examined the incidence of gastritis and gastric ulcer to the stomach contour variation. Of total 1,546 patients, eutonic stomach were 438(28.3%), hypotonic 911(58.9%), steerhorn 102(6.5%) and cascade 95(6.2%). Stomach cancer was found in 139(31.7%) of 438 eutonic stomachs, in 135(14.8%) of 911 hypotonic, in 42(41.2%) of 102 steerhorn, and in 24(36.9%) of 95 cascade (P=0.001). In hypotonic stomach, the incidence of stomach cancer was lower compared to the other three types significantly (p<0.05). Gastritis or gastric ulcer was found in 146(33.3%) of eutonic stomach, in 293(32.1%) of hypotonic, in 36(35.2%) of steerhorn, and in 26(27.3%) of cascade (p=0.640). In conclusion, gastric contour variation seems to be a factor affecting development of stomach cancer. The patients with hypotonic stomach may have lower incidence of stomach cancer than that of the other types. There was no relationship between the contour and gastric ulcer.

  6. Quantitative right and left ventricular functional analysis during gated whole-chest MDCT: A feasibility study comparing automatic segmentation to semi-manual contouring

    Energy Technology Data Exchange (ETDEWEB)

    Coche, Emmanuel, E-mail: Emmanuel.coche@uclouvain.b [Department of Medical Imaging, Universite Catholique de Louvain, Cliniques Universitaires St-Luc (UCL), Avenue Hippocrate, 10, 1200 Brussels (Belgium); Walker, Matthew J. [Philips Healthcare, CT Clinical Science, Cleveland, OH (United States); Zech, Francis [Department of Internal Medicine, Universite Catholique de Louvain, Cliniques Universitaires St-Luc, Brussels (Belgium); Crombrugghe, Rodolphe de [Department of Medical Imaging, Universite Catholique de Louvain, Cliniques Universitaires St-Luc (UCL), Avenue Hippocrate, 10, 1200 Brussels (Belgium); Vlassenbroek, Alain [Philips Healthcare, Brussels (Belgium)

    2010-06-15

    Purpose: To evaluate the feasibility of an automatic, whole-heart segmentation algorithm for measuring global heart function from gated, whole-chest MDCT images. Material and methods: 15 patients with suspicion of PE underwent whole-chest contrast-enhanced MDCT with retrospective ECG synchronization. Two observers computed right and left ventricular functional indices using a semi-manual and an automatic whole-heart segmentation algorithm. The two techniques were compared using Bland-Altman analysis and paired Student's t-test. Measurement reproducibility was calculated using intraclass correlation coefficient. Results: Ventricular analysis with automatic segmentation was successful in 13/15 (86%) and in 15/15 (100%) patients for the right ventricle and left ventricle, respectively. Reproducibility of measurements for both ventricles was perfect (ICC: 1.00) and very good for automatic and semi-manual measurements, respectively. Ventricular volumes and functional indices except right ventricular ejection fraction obtained from the automatic method were significantly higher for the RV compared to the semi-manual methods. Conclusions: The automatic, whole-heart segmentation algorithm enabled highly reproducible global heart function to be rapidly obtained in patients undergoing gated whole-chest MDCT for assessment of acute chest pain with suspicion of pulmonary embolism.

  7. Genomic pathways modulated by Twist in breast cancer

    OpenAIRE

    Vesuna, Farhad; Bergman, Yehudit; Raman, Venu

    2017-01-01

    Background The basic helix-loop-helix transcription factor TWIST1 (Twist) is involved in embryonic cell lineage determination and mesodermal differentiation. There is evidence to indicate that Twist expression plays a role in breast tumor formation and metastasis, but the role of Twist in dysregulating pathways that drive the metastatic cascade is unclear. Moreover, many of the genes and pathways dysregulated by Twist in cell lines and mouse models have not been validated against data obtaine...

  8. DDalphaAMG for Twisted Mass Fermions

    CERN Document Server

    Bacchio, Simone; Finkenrath, Jacob; Frommer, Andreas; Kahl, Karsten; Rottmann, Matthias

    2016-01-01

    We present the Adaptive Aggregation-based Domain Decomposition Multigrid method extended to the twisted mass fermion discretization action. We show comparisons of results as a function of tuning the parameters that enter the twisted mass version of the DDalphaAMG library (https://github.com/sbacchio/DDalphaAMG). Moreover, we linked the DDalphaAMG library to the tmLQCD software package and give details on the performance of the multigrid solver during HMC simulations at the physical point.

  9. Twisted Covariant Noncommutative Self-dual Gravity

    CERN Document Server

    Estrada-Jimenez, S; Obregón, O; Ramírez, C

    2008-01-01

    A twisted covariant formulation of noncommutative self-dual gravity is presented. The recent formulation introduced by J. Wess and coworkers for constructing twisted Yang-Mills fields is used. It is shown that the noncommutative torsion is solved at any order of the $\\theta$-expansion in terms of the tetrad and the extra fields of the theory. In the process the first order expansion in $\\theta$ for the Pleba\\'nski action is explicitly obtained.

  10. OAM mode converter in twisted fibers

    DEFF Research Database (Denmark)

    Usuga Castaneda, Mario A.; Beltran-Mejia, Felipe; Cordeiro, Cristiano

    2014-01-01

    We analyze the case of an OAM mode converter based on a twisted fiber, through finite element simulations where we exploit an equivalence between geometric and material transformations. The obtained converter has potential applications in MDM. © 2014 OSA.......We analyze the case of an OAM mode converter based on a twisted fiber, through finite element simulations where we exploit an equivalence between geometric and material transformations. The obtained converter has potential applications in MDM. © 2014 OSA....

  11. On Supermultiplet Twisting and Spin-Statistics

    CERN Document Server

    Hubsch, Tristan

    2012-01-01

    Twisting of off-shell supermultiplets in models with 1+1-dimensional spacetime has been discovered in 1984, and was shown to be a generic feature of off-shell representations in worldline supersymmetry two decades later. It is shown herein that in all supersymmetric models with spacetime of four or more dimensions, this type of twisting, if nontrivial, necessarily maps regular (non-ghost) supermultiplets to ghost supermultiplets.

  12. On Supermultiplet Twisting and Spin-Statistics

    OpenAIRE

    Hubsch, Tristan

    2012-01-01

    Twisting of off-shell supermultiplets in models with 1+1-dimensional spacetime has been discovered in 1984, and was shown to be a generic feature of off-shell representations in worldline supersymmetry two decades later. It is shown herein that in all supersymmetric models with spacetime of four or more dimensions, this off-shell supermultiplet twisting, if non-trivial, necessarily maps regular (non-ghost) supermultiplets to ghost supermultiplets. This feature is shown to be ubiquitous in all...

  13. The gradient flow in a twisted box

    Energy Technology Data Exchange (ETDEWEB)

    Ramos, Alberto [Deutsches Elektronen-Synchrotron (DESY), Zeuthen (Germany). John von Neumann-Inst. fuer Computing NIC

    2013-08-15

    We study the perturbative behavior of the gradient flow in a twisted box. We apply this information to define a running coupling using the energy density of the flow field. We study the step-scaling function and the size of cutoff effects in SU(2) pure gauge theory. We conclude that the twisted gradient flow running coupling scheme is a valid strategy for step-scaling purposes due to the relatively mild cutoff effects and high precision.

  14. Twisted Boundary Conditions in Lattice Simulations

    CERN Document Server

    Sachrajda, Christopher T C

    2004-01-01

    By imposing twisted boundary conditions on quark fields it is possible to access components of momenta other than integer multiples of 2pi/L on a lattice with spatial volume L^3. We use Chiral Perturbation Theory to study finite-volume effects with twisted boundary conditions for quantities without final-state interactions, such as meson masses, decay constants and semileptonic form factors, and confirm that they remain exponentially small with the volume. We show that this is also the case for "partially twisted" boundary conditions, in which (some of) the valence quarks satisfy twisted boundary conditions but the sea quarks satisfy periodic boundary conditions. This observation implies that it is not necessary to generate new gluon configurations for every choice of the twist angle, making the method much more practicable. For K->pipi decays we show that the breaking of isospin symmetry by the twisted boundary conditions implies that the amplitudes cannot be determined in general (on this point we disagree ...

  15. An automatic contour propagation method to follow parotid gland deformation during head-and-neck cancer tomotherapy

    Energy Technology Data Exchange (ETDEWEB)

    Faggiano, E; Scalco, E; Rizzo, G [Istituto di Bioimmagini e Fisiologia Molecolare (IBFM), CNR, Milan (Italy); Fiorino, C; Broggi, S; Cattaneo, M; Maggiulli, E; Calandrino, R [Department of Medical Physics, San Raffaele Scientific Institute, Milan (Italy); Dell' Oca, I; Di Muzio, N, E-mail: fiorino.claudio@hsr.it [Department of Radiotherapy, San Raffaele Scientific Institute, Milan (Italy)

    2011-02-07

    We developed an efficient technique to auto-propagate parotid gland contours from planning kVCT to daily MVCT images of head-and-neck cancer patients treated with helical tomotherapy. The method deformed a 3D surface mesh constructed from manual kVCT contours by B-spline free-form deformation to generate optimal and smooth contours. Deformation was calculated by elastic image registration between kVCT and MVCT images. Data from ten head-and-neck cancer patients were considered and manual contours by three observers were included in both kVCT and MVCT images. A preliminary inter-observer variability analysis demonstrated the importance of contour propagation in tomotherapy application: a high variability was reported in MVCT parotid volume estimation (p = 0.0176, ANOVA test) and a larger uncertainty of MVCT contouring compared with kVCT was demonstrated by DICE and volume variability indices (Wilcoxon signed rank test, p < 10{sup -4} for both indices). The performance analysis of our method showed no significant differences between automatic and manual contours in terms of volumes (p > 0.05, in a multiple comparison Tukey test), center-of-mass distances (p = 0.3043, ANOVA test), DICE values (p = 0.1672, Wilcoxon signed rank test) and average and maximum symmetric distances (p = 0.2043, p = 0.8228 Wilcoxon signed rank tests). Results suggested that our contour propagation method could successfully substitute human contouring on MVCT images.

  16. Emotion identification using extremely low frequency components of speech feature contours.

    Science.gov (United States)

    Lin, Chang-Hong; Liao, Wei-Kai; Hsieh, Wen-Chi; Liao, Wei-Jiun; Wang, Jia-Ching

    2014-01-01

    The investigations of emotional speech identification can be divided into two main parts, features and classifiers. In this paper, how to extract an effective speech feature set for the emotional speech identification is addressed. In our speech feature set, we use not only statistical analysis of frame-based acoustical features, but also the approximated speech feature contours, which are obtained by extracting extremely low frequency components to speech feature contours. Furthermore, principal component analysis (PCA) is applied to the approximated speech feature contours so that an efficient representation of approximated contours can be derived. The proposed speech feature set is fed into support vector machines (SVMs) to perform multiclass emotion identification. The experimental results demonstrate the performance of the proposed system with 82.26% identification rate.

  17. Increased risk for developmental delay in Saethre-Chotzen syndrome is associated with TWIST deletions: an improved strategy for TWIST mutation screening.

    Science.gov (United States)

    Cai, Juanliang; Goodman, Barbara K; Patel, Ankita S; Mulliken, John B; Van Maldergem, Lionel; Hoganson, George E; Paznekas, William A; Ben-Neriah, Ziva; Sheffer, Ruth; Cunningham, Michael L; Daentl, Donna L; Jabs, Ethylin Wang

    2003-12-01

    The majority of patients with Saethre-Chotzen syndrome have mutations in the TWIST gene, which codes for a basic helix-loop-helix transcription factor. Of the genetic alterations identified in TWIST, nonsense mutations, frameshifts secondary to small deletions or insertions, and large deletions implicate haploinsufficiency as the pathogenic mechanism. We identified three novel intragenic mutations and six deletions in our patients by using a new strategy to screen for TWIST mutations. We used polymerase chain reaction (PCR) amplification with subsequent sequencing to identify point mutations and small insertions or deletions in the coding region, and real-time PCR-based gene dosage analysis to identify large deletions encompassing the gene, with confirmation by microsatellite and fluorescence in situ hybridization (FISH) analyses. The size of the deletions can also be analyzed by using the gene dosage assay with "PCR walking" across the critical region. In 55 patients with features of Saethre-Chotzen syndrome, 11% were detected to have deletions by real-time gene dosage analysis. Two patients had a translocation or inversion at least 260 kb 3' of the gene, suggesting they had position-effect mutations. Of the 37 patients with classic features of Saethre-Chotzen syndrome, the overall detection rate for TWIST mutations was 68%. The risk for developmental delay in patients with deletions involving the TWIST gene is approximately 90% or eight times more common than in patients with intragenic mutations.

  18. Integral Twist Actuation of Helicopter Rotor Blades for Vibration Reduction

    Science.gov (United States)

    Shin, SangJoon; Cesnik, Carlos E. S.

    2001-01-01

    Active integral twist control for vibration reduction of helicopter rotors during forward flight is investigated. The twist deformation is obtained using embedded anisotropic piezocomposite actuators. An analytical framework is developed to examine integrally-twisted blades and their aeroelastic response during different flight conditions: frequency domain analysis for hover, and time domain analysis for forward flight. Both stem from the same three-dimensional electroelastic beam formulation with geometrical-exactness, and axe coupled with a finite-state dynamic inflow aerodynamics model. A prototype Active Twist Rotor blade was designed with this framework using Active Fiber Composites as the actuator. The ATR prototype blade was successfully tested under non-rotating conditions. Hover testing was conducted to evaluate structural integrity and dynamic response. In both conditions, a very good correlation was obtained against the analysis. Finally, a four-bladed ATR system is built and tested to demonstrate its concept in forward flight. This experiment was conducted at NASA Langley Tansonic Dynamics Tunnel and represents the first-of-a-kind Mach-scaled fully-active-twist rotor system to undergo forward flight test. In parallel, the impact upon the fixed- and rotating-system loads is estimated by the analysis. While discrepancies are found in the amplitude of the loads under actuation, the predicted trend of load variation with respect to its control phase correlates well. It was also shown, both experimentally and numerically, that the ATR blade design has the potential for hub vibratory load reduction of up to 90% using individual blade control actuation. Using the numerical framework, system identification is performed to estimate the harmonic transfer functions. The linear time-periodic system can be represented by a linear time-invariant system under the three modes of blade actuation: collective, longitudinal cyclic, and lateral cyclic. A vibration

  19. Variations in the Contouring of Organs at Risk: Test Case From a Patient With Oropharyngeal Cancer

    Energy Technology Data Exchange (ETDEWEB)

    Nelms, Benjamin E., E-mail: alpha@canislupusllc.com [Canis Lupus LLC, Merrimac, WI (United States); Tome, Wolfgang A. [Department of Human Oncology, University of Wisconsin, Madison, WI (United States); Robinson, Greg [Radiation Oncology Resources, Goshen, IN (United States); Wheeler, James [Department of Radiation Oncology, Goshen Health System Goshen, IN (United States)

    2012-01-01

    Purpose: Anatomy contouring is critical in radiation therapy. Inaccuracy and variation in defining critical volumes will affect everything downstream: treatment planning, dose-volume histogram analysis, and contour-based visual guidance used in image-guided radiation therapy. This study quantified: (1) variation in the contouring of organs at risk (OAR) in a clinical test case and (2) corresponding effects on dosimetric metrics of highly conformal plans. Methods and Materials: A common CT data set with predefined targets from a patient with oropharyngeal cancer was provided to a population of clinics, which were asked to (1) contour OARs and (2) design an intensity-modulated radiation therapy plan. Thirty-two acceptable plans were submitted as DICOM RT data sets, each generated by a different clinical team. Using those data sets, we quantified: (1) the OAR contouring variation and (2) the impact this variation has on dosimetric metrics. New technologies were employed, including a software tool to quantify three-dimensional structure comparisons. Results: There was significant interclinician variation in OAR contouring. The degree of variation is organ-dependent. We found substantial dose differences resulting strictly from contouring variation (differences ranging from -289% to 56% for mean OAR dose; -22% to 35% for maximum dose). However, there appears to be a threshold in the OAR comparison metric beyond which the dose differences stabilize. Conclusions: The effects of interclinician variation in contouring organs-at-risk in the head and neck can be large and are organ-specific. Physicians need to be aware of the effect that variation in OAR contouring can play on the final treatment plan and not restrict their focus only to the target volumes.

  20. A FUZZY FILTERING MODEL FOR CONTOUR DETECTION

    Directory of Open Access Journals (Sweden)

    T.C. Rajakumar

    2011-04-01

    Full Text Available Contour detection is the basic property of image processing. Fuzzy Filtering technique is proposed to generate thick edges in two dimensional gray images. Fuzzy logic is applied to extract value for an image and is used for object contour detection. Fuzzy based pixel selection can reduce the drawbacks of conventional methods(Prewitt, Robert. In the traditional methods, filter mask is used for all kinds of images. It may succeed in one kind of image but fail in another one. In this frame work the threshold parameter values are obtained from the fuzzy histogram of the input image. The Fuzzy inference method selects the complete information about the border of the object and the resultant image has less impulse noise and the contrast of the edge is increased. The extracted object contour is thicker than the existing methods. The performance of the algorithm is tested with Peak Signal Noise Ratio(PSNR and Complex Wavelet Structural Similarity Metrics(CWSSIM.

  1. Maintaining Contour Trees of Dynamic Terrains

    DEFF Research Database (Denmark)

    Agarwal, Pankaj K.; Arge, Lars; Mølhave, Thomas

    We consider maintaining the contour tree T of a piecewise-linear triangulation M that is the graph of a time varying height function h:R2→R. We carefully describe the combinatorial change in T that happen as h varies over time and how these changes relate to topological changes in M. We present...... a kinetic data structure that maintains the contour tree of h over time. Our data structure maintains certificates that fail only when h(v)=h(u) for two adjacent vertices v and u in M, or when two saddle vertices lie on the same contour of M. A certificate failure is handled in O(log(n)) time. We also show...

  2. Coding Long Contour Shapes of Binary Objects

    Science.gov (United States)

    Sánchez-Cruz, Hermilo; Rodríguez-Díaz, Mario A.

    This is an extension of the paper appeared in [15]. This time, we compare four methods: Arithmetic coding applied to 3OT chain code (Arith-3OT), Arithmetic coding applied to DFCCE (Arith-DFCCE), Huffman coding applied to DFCCE chain code (Huff-DFCCE), and, to measure the efficiency of the chain codes, we propose to compare the methods with JBIG, which constitutes an international standard. In the aim to look for a suitable and better representation of contour shapes, our probes suggest that a sound method to represent contour shapes is 3OT, because Arithmetic coding applied to it gives the best results regarding JBIG, independently of the perimeter of the contour shapes.

  3. TU-C-17A-03: An Integrated Contour Evaluation Software Tool Using Supervised Pattern Recognition for Radiotherapy

    Energy Technology Data Exchange (ETDEWEB)

    Chen, H; Tan, J; Kavanaugh, J; Dolly, S; Gay, H; Thorstad, W; Anastasio, M; Altman, M; Mutic, S; Li, H [Washington University School of Medicine, Saint Louis, MO (United States)

    2014-06-15

    Purpose: Radiotherapy (RT) contours delineated either manually or semiautomatically require verification before clinical usage. Manual evaluation is very time consuming. A new integrated software tool using supervised pattern contour recognition was thus developed to facilitate this process. Methods: The contouring tool was developed using an object-oriented programming language C# and application programming interfaces, e.g. visualization toolkit (VTK). The C# language served as the tool design basis. The Accord.Net scientific computing libraries were utilized for the required statistical data processing and pattern recognition, while the VTK was used to build and render 3-D mesh models from critical RT structures in real-time and 360° visualization. Principal component analysis (PCA) was used for system self-updating geometry variations of normal structures based on physician-approved RT contours as a training dataset. The inhouse design of supervised PCA-based contour recognition method was used for automatically evaluating contour normality/abnormality. The function for reporting the contour evaluation results was implemented by using C# and Windows Form Designer. Results: The software input was RT simulation images and RT structures from commercial clinical treatment planning systems. Several abilities were demonstrated: automatic assessment of RT contours, file loading/saving of various modality medical images and RT contours, and generation/visualization of 3-D images and anatomical models. Moreover, it supported the 360° rendering of the RT structures in a multi-slice view, which allows physicians to visually check and edit abnormally contoured structures. Conclusion: This new software integrates the supervised learning framework with image processing and graphical visualization modules for RT contour verification. This tool has great potential for facilitating treatment planning with the assistance of an automatic contour evaluation module in avoiding

  4. Bend-twist coupling potential of wind turbine blades

    Science.gov (United States)

    Fedorov, V.; Berggreen, C.

    2014-06-01

    In the present study an evaluation of the potential for bend-twist coupling effects in wind turbine blades is addressed. A method for evaluation of the coupling magnitude based on the results of finite element modeling and full-field displacement measurements obtained by experiments is developed and tested on small-scale coupled composite beams. In the proposed method the coupling coefficient for a generic beam is introduced based on the Euler-Bernoulli beam formulation. By applying the developed method for analysis of a commercial wind turbine blade structure it is demonstrated that a bend-twist coupling magnitude of up to 0.2 is feasible to achieve in the baseline blade structure made of glass-fiber reinforced plastics. Further, by substituting the glass-fibers with carbon-fibers the coupling effect can be increased to 0.4. Additionally, the effect of introduction of bend-twist coupling into a blade on such important blade structural properties as bending and torsional stiffness is demonstrated.

  5. Intercellular Genetic Interaction Between Irf6 and Twist1 during Craniofacial Development.

    Science.gov (United States)

    Fakhouri, Walid D; Metwalli, Kareem; Naji, Ali; Bakhiet, Sarah; Quispe-Salcedo, Angela; Nitschke, Larissa; Kousa, Youssef A; Schutte, Brian C

    2017-08-02

    Interferon Regulatory Factor 6 (IRF6) and TWIST1 are transcription factors necessary for craniofacial development. Human genetic studies showed that mutations in IRF6 lead to cleft lip and palate and mandibular abnormalities. In the mouse, we found that loss of Irf6 causes craniosynostosis and mandibular hypoplasia. Similarly, mutations in TWIST1 cause craniosynostosis, mandibular hypoplasia and cleft palate. Based on this phenotypic overlap, we asked if Irf6 and Twist1 interact genetically during craniofacial formation. While single heterozygous mice are normal, double heterozygous embryos (Irf6 (+/-) ; Twist1 (+/-) ) can have severe mandibular hypoplasia that leads to agnathia and cleft palate at birth. Analysis of spatiotemporal expression showed that Irf6 and Twist1 are found in different cell types. Consistent with the intercellular interaction, we found reduced expression of Endothelin1 (EDN1) in mandible and transcription factors that are critical for mandibular patterning including DLX5, DLX6 and HAND2, were also reduced in mesenchymal cells. Treatment of mandibular explants with exogenous EDN1 peptides partially rescued abnormalities in Meckel's cartilage. In addition, partial rescue was observed when double heterozygous embryos also carried a null allele of p53. Considering that variants in IRF6 and TWIST1 contribute to human craniofacial defects, this gene-gene interaction may have implications on craniofacial disorders.

  6. Phase Diagram of Dynamical Twisted Mass Wilson Fermions at Finite Isospin Chemical Potential

    CERN Document Server

    Janssen, Oliver; Splittorff, K; Verbaarschot, Jacobus J M; Zafeiropoulos, Savvas

    2015-01-01

    We consider the phase diagram of twisted mass Wilson fermions of two-flavor QCD in the parameter space of the quark mass, the isospin chemical potential, the twist angle and the lattice spacing. This work extends earlier studies in the continuum and those at zero chemical potential. We evaluate the phase diagram as well as the spectrum of the (pseudo-)Goldstone bosons using the chiral Lagrangian for twisted mass Wilson fermions at non-zero isospin chemical potential. The phases are obtained from a mean field analysis. At zero twist angle we find that already an infinitesimal isospin chemical potential destroys the Aoki phase. The reason is that in this phase we have massless Goldstone bosons with a non-zero isospin charge. At finite twist angle only two different phases are present, one phase which is continuously connected to the Bose condensed phase at non-zero chemical potential and another phase which is continuously connected to the normal phase. For either zero or maximal twist the phase diagram is more...

  7. Conversion of contours to cartesian grids

    Energy Technology Data Exchange (ETDEWEB)

    Mann, J.; Broe, B. Riget

    2006-07-15

    A robust and efficient method of calculating a cartesian grid of heights or roughnesses from contour line maps is developed. The purpose of the grids is to serve as input for atmospheric flow solvers such as WAsP Engineering or EllipSys3D. The method builds on Delaunay triangulation constrained to include all contour segments in the triangulation. It is furthermore refined to avoid spurious flat areas produced by the Delaunay triangulation. Robust ways to extrapolate beyond the convex hull of the map points are provided. (au)

  8. Conversion of contours to cartesian grids

    DEFF Research Database (Denmark)

    Mann, Jakob; Broe, Brian Riget

    A robust and efficient method of calculating a cartesian grid of heights or roughnesses from contour line maps is developed. The purpose of the grids is to serve as input for atmospheric flow solvers such as WAsP Engineering or EllipSys3D. The method builds on Delaunay triangulation constrained t...... to include all contour segments in the triangulation. It is furthermore refined to avoid spurious flat areas produced by the Delaunay triangulation. Robust ways to extrapolate beyond the convex hull of the map points are provided....

  9. Soft tissue twisting injuries of the knee

    Energy Technology Data Exchange (ETDEWEB)

    Magee, T.; Shapiro, M. [Neuroimaging Inst., Melbourne, FL (United States)

    2001-08-01

    Twisting injuries occur as a result of differential motion of different tissue types in injuries with some rotational force. These injuries are well described in brain injuries but, to our knowledge, have not been described in the musculoskeletal literature. We correlated the clinical examination and MR findings of 20 patients with twisting injuries of the soft tissues around the knee. Design and patients: We prospectively followed the clinical courses of 20 patients with knee injuries who had clinical histories and MR findings to suggest twisting injuries of the subcutaneous tissues. Patients with associated internal derangement of the knee (i.e., meniscal tears, ligamentous or bone injuries) were excluded from this study. MR findings to suggest twisting injuries included linear areas of abnormal dark signal on T1-weighted sequences and abnormal bright signal on T2-weighted or short tau inversion recovery (STIR) sequences and/or signal to suggest hemorrhage within the subcutaneous tissues. These MR criteria were adapted from those established for indirect musculotendinous junction injuries. Results: All 20 patients presented with considerable pain that suggested internal derangement on physical examination by the referring orthopedic surgeons. All presented with injuries associated with rotational force. The patients were placed on a course of protected weight-bearing of the affected extremity for 4 weeks. All patients had pain relief by clinical examination after this period of protected weight-bearing. Twisting injuries of the soft tissues can result in considerable pain that can be confused with internal derangement of the knee on physical examination. Soft tissue twisting injuries need to be recognized on MR examinations as they may be the cause of the patient's pain despite no MR evidence of internal derangement of the knee. The demonstration of soft tissue twisting injuries in a patient with severe knee pain but no documented internal derangement on MR

  10. A multi-scale approach to mass segmentation using active contour models

    Science.gov (United States)

    Yu, Hongwei; Li, Lihua; Xu, Weidong; Liu, Wei

    2010-03-01

    As an important step of mass classification, mass segmentation plays an important role in computer-aided diagnosis (CAD). In this paper, we propose a novel scheme for breast mass segmentation in mammograms, which is based on level set method and multi-scale analysis. Mammogram is firstly decomposed by Gaussian pyramid into a sequence of images from fine to coarse, the C-V model is then applied at the coarse scale, and the obtained rough contour is used as the initial contour for segmentation at the fine scale. A local active contour (LAC) model based on image local information is utilized to refine the rough contour locally at the fine scale. In addition, the feature of area and gray level extracted from coarse segmentation is used to set the parameters of LAC model automatically to improve the adaptivity of our method. The results show the higher accuracy and robustness of the proposed multi-scale segmentation method than the conventional ones.

  11. Noncommutative geometry in string and twisted Hopf algebra of diffeomorphism

    Science.gov (United States)

    Watamura, Satoshi

    2011-09-01

    We discuss the Hopf algebra structure in string theory and present the twist quantization as a unified formulation of the world sheet quantization of the string and the symmetry of the target spacetime. Applying it to the case with a nonzero B-field background, we explain a method to decompose the twist into two successive twists. There are two different possibilities of decomposition: The first is a natural decomposition from the viewpoint of the twist quantization, leading to a new type of twisted Poincaré symmetry. The second decomposition reveals the relation of our formulation to the twisted Poincaré symmetry on the Moyal type noncommutative space.

  12. Twisted electron-acoustic waves in plasmas

    Science.gov (United States)

    Aman-ur-Rehman, Ali, S.; Khan, S. A.; Shahzad, K.

    2016-08-01

    In the paraxial limit, a twisted electron-acoustic (EA) wave is studied in a collisionless unmagnetized plasma, whose constituents are the dynamical cold electrons and Boltzmannian hot electrons in the background of static positive ions. The analytical and numerical solutions of the plasma kinetic equation suggest that EA waves with finite amount of orbital angular momentum exhibit a twist in its behavior. The twisted wave particle resonance is also taken into consideration that has been appeared through the effective wave number qeff accounting for Laguerre-Gaussian mode profiles attributed to helical phase structures. Consequently, the dispersion relation and the damping rate of the EA waves are significantly modified with the twisted parameter η, and for η → ∞, the results coincide with the straight propagating plane EA waves. Numerically, new features of twisted EA waves are identified by considering various regimes of wavelength and the results might be useful for transport and trapping of plasma particles in a two-electron component plasma.

  13. Contour Interaction in Visual Space.

    Science.gov (United States)

    1981-06-01

    Systems Command Dr. Alfred F. Smode Human Factors Programs Training Analysis and Evaluation NAVAIR 340F Group Washington, D.C. 20361 Naval Training...Lloyd Hitchcock 333 Ravensworth Avenue Federal Aviation Administration Menlo Park, CA 94025 ACT 200 Atlantic City Airport, NJ 08405 Dr. Edward R

  14. Contour detection by surround suppression of texture

    NARCIS (Netherlands)

    Petkov, Nicolai; Tavares, JMRS; Jorge, RMN

    2007-01-01

    Based on a keynote lecture at Complmage 2006, Coimbra, Oct. 20-21, 2006, an overview is given of our activities in modelling and using surround inhibition for contour detection. The effect of suppression of a line or edge stimulus by similar surrounding stimuli is known from visual perception studie

  15. Contours--Offshore of Carpinteria, California

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — This part of SIM 3261 presents data for the bathymetric contours for several seafloor maps (see sheets 1, 2, 3, 5 [in figs. 1, 2, 3], 7, 10, SIM 3261) of the...

  16. Contours--Offshore of Santa Barbara, California

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — This part of SIM 3281 presents data for the bathymetric contours for several seafloor maps (see sheets 1, 2, 3, 7, 10, SIM 3281) of the Offshore of Santa Barbara map...

  17. Maintaining Contour Trees of Dynamic Terrains

    DEFF Research Database (Denmark)

    Agarwal, Pankaj K.; Arge, Lars; Mølhave, Thomas

    We consider maintaining the contour tree T of a piecewise-linear triangulation M that is the graph of a time varying height function h:R2→R. We carefully describe the combinatorial change in T that happen as h varies over time and how these changes relate to topological changes in M. We present...

  18. An Active Contour for Range Image Segmentation

    Directory of Open Access Journals (Sweden)

    Khaldi Amine

    2012-06-01

    Full Text Available In this paper a new classification of range image segmentation method is proposed according to the criterion of homogeneity which obeys the segmentation, then, a deformable model-type active contour “Snake” is applied to segment range images.

  19. Regression Model With Elliptically Contoured Errors

    CERN Document Server

    Arashi, M; Tabatabaey, S M M

    2012-01-01

    For the regression model where the errors follow the elliptically contoured distribution (ECD), we consider the least squares (LS), restricted LS (RLS), preliminary test (PT), Stein-type shrinkage (S) and positive-rule shrinkage (PRS) estimators for the regression parameters. We compare the quadratic risks of the estimators to determine the relative dominance properties of the five estimators.

  20. Contours--Offshore of Carpinteria, California

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — This part of SIM 3261 presents data for the bathymetric contours for several seafloor maps (see sheets 1, 2, 3, 5 [in figs. 1, 2, 3], 7, 10, SIM 3261) of the...

  1. Automatic contour welder incorporates speed control system

    Science.gov (United States)

    Wall, W. A., Jr.

    1968-01-01

    Speed control system maintains the welding torch of an automatic welder at a substantially constant speed. The system is particularly useful when welding contoured or unusually shaped surfaces, which cause the distance from the work surface to the weld carriage to vary in a random manner.

  2. Maintaining Contour Trees of Dynamic Terrains

    DEFF Research Database (Denmark)

    Agarwal, Pankaj K.; Mølhave, Thomas; Revsbæk, Morten;

    2015-01-01

    We study the problem of maintaining the contour tree T of a terrain Sigma, represented as a triangulated xy-monotone surface, as the heights of its vertices vary continuously with time. We characterize the combinatorial changes in T and how they relate to topological changes in Sigma. We present ...

  3. Contours--Offshore of San Gregorio, California

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — This part of SIM 3306 presents data for the bathymetric contours for several seafloor maps (see sheets 1, 2, 3, 7, 10, SIM 3306) of the Offshore of San Gregorio map...

  4. Twist modulates lymphangiogenesis and correlates with lymph node metastasis in supraglottic carcinoma

    Institute of Scientific and Technical Information of China (English)

    LU Su-mei; YU Liang; TIAN Jia-jun; MA Ju-ke; LI Jian-feng; XU Wei; WANG Hai-bo

    2011-01-01

    Background Twist is a highly conserved epithelial-mesenchymal transcription factor that has been reported to be a key factor in tumor malignancy, including lymph node metastasis. It represents the major step of dissemination and serves as a chief prognostic indicator of disease progression. However, the mechanism by which Twist regulates lymph node metastasis remains incompletely understood. Studies on the mechanism of metastasis are thus required for determining appropriate therapeutic strategies.Methods Immunohistochemistry for lymphatic vessel endothelial receptor 1 (LYVE-1), Ki-67, Twist, vascular endothelial growth factor C (VEGF-C), and vascular endothelial growth factor receptor 3 (VEGFR-3) was performed to detect lymphatic vessel density (LVD), cell proliferation levels and the expressions of Twist, VEGF-C, and VEGFR-3 were determined from 66 primary supraglottic carcinoma tissue samples from 36 patients with lymph node metastasis (pathological N+, pN+) and 30 patients without metastasis (pathological NO, pNO). Western blotting analysis of the proteins in pN+ and pNO primary tumors was used to characterize the expressions of Twist, VEGF-C, and VEGFR-3further.Results The LVD was 22.4±10.3 in pN+ patients and 6.8±4.1 in pNO ones. For Ki-67, the number of proliferous cells in pN+ patients was greater than that in pNO ones. Both, however, were associated with their clinical nodal stages. In pN+patients, Twist, VEGF-C, and VEGFR-3 expressions were 86.11% (31/36), 80.56% (29/36), and 58.33% (21/36),respectively. These values were higher than those found for pNO patients (i.e., 13/30, 11/30, and 7/30, respectively) (P <0.05). Among the samples with Twist expression, 88.64% were VEGF-C-positive and 59.09% were VEGFR-3-positive.The pNO counterparts were 4.55% and 9.09%, respectively (P<0.05). The expressions of Twist, VEGF-C, and VEGFR-3in pN+ patients obtained through Western blotting analysis were significantly higher than those in pNO patients, and the

  5. Exotic twisted equivariant cohomology of loop spaces,twisted Bismut-Chern character and T-duality

    CERN Document Server

    Han, Fei

    2014-01-01

    We define completed periodic {\\em exotic twisted $\\mathbb{T}$-equivariant cohomology} for loop spaces of smooth manifolds. We then show that the twisted Bismut-Chern character, defined on the twisted K-theory of the smooth manifold, twisted by a gerbe with connection, takes values in the completed periodic exotic twisted $\\mathbb{T}$-equivariant cohomology of the loop space of the smooth manifold. We establish a localisation theorem for the completed periodic exotic twisted $\\mathbb{T}$-equivariant cohomology for loop spaces and apply it to establish T-duality in a background flux in type II String Theory from a loop space perspective.

  6. Helicoids, wrinkles, and loops in twisted ribbons.

    Science.gov (United States)

    Chopin, Julien; Kudrolli, Arshad

    2013-10-25

    We investigate the instabilities of a flat elastic ribbon subject to twist under tension and develop an integrated phase diagram of the observed shapes and transitions. We find that the primary buckling mode switches from being localized longitudinally along the length of the ribbon to transverse above a triple point characterized by a crossover tension that scales with ribbon elasticity and aspect ratio. Far from threshold, the longitudinally buckled ribbon evolves continuously into a self-creased helicoid with focusing of the curvature along the triangular edges. Further twist causes an anomalous transition to loops compared with rods due to the self-rigidity induced by the creases. When the ribbon is twisted under high tension, transverse wrinkles are observed due to the development of compressive stresses with higher harmonics for greater width-to-length ratios. Our results can be used to develop functional structures using a wide range of elastic materials and length scales.

  7. Dynamical Twisted Mass Fermions with Light Quarks

    CERN Document Server

    Boucaud, P; Farchioni, F; Frezzotti, R; Giménez, V; Herdoiza, G; Jansen, K; Lubicz, V; Martinelli, G; McNeile, C; Michael, C; Montvay, I; Palao, D; Papinutto, Mauro; Pickavance, J; Rossi, G C; Scorzato, L; Shindler, A; Simula, S; Urbach, C; Wenger, U; Boucaud, Ph.

    2007-01-01

    We present results of dynamical simulations with 2 flavours of degenerate Wilson twisted mass quarks at maximal twist in the range of pseudo scalar masses from 300 to 550 MeV. The simulations are performed at one value of the lattice spacing a \\lesssim 0.1 fm. In order to have O(a) improvement and aiming at small residual cutoff effects, the theory is tuned to maximal twist by requiring the vanishing of the untwisted quark mass. Precise results for the pseudo scalar decay constant and the pseudo scalar mass are confronted with chiral perturbation theory predictions and the low energy constants F, \\bar{l}_3 and \\bar{l}_4 are evaluated with small statistical errors.

  8. Matrix theory compactifications on twisted tori

    CERN Document Server

    Chatzistavrakidis, Athanasios

    2012-01-01

    We study compactifications of Matrix theory on twisted tori and non-commutative versions of them. As a first step, we review the construction of multidimensional twisted tori realized as nilmanifolds based on certain nilpotent Lie algebras. Subsequently, matrix compactifications on tori are revisited and the previously known results are supplemented with a background of a non-commutative torus with non-constant non-commutativity and an underlying non-associative structure on its phase space. Next we turn our attention to 3- and 6-dimensional twisted tori and we describe consistent backgrounds of Matrix theory on them by stating and solving the conditions which describe the corresponding compactification. Both commutative and non-commutative solutions are found in all cases. Finally, we comment on the correspondence among the obtained solutions and flux compactifications of 11-dimensional supergravity, as well as on relations among themselves, such as Seiberg-Witten maps and T-duality.

  9. On reweighting for twisted boundary conditions

    CERN Document Server

    Bussone, Andrea; Hansen, Martin; Pica, Claudio

    2016-01-01

    We consider the possibility of using reweighting techniques in order to correct for the breaking of unitarity when twisted boundary conditions are imposed on valence fermions in simulations of lattice gauge theories. We start by studying the properties of reweighting factors and their variances at tree-level. That leads us to the introduction of a factorization for the fermionic reweighting determinant. In the numerical, stochastic, implementation of the method, we find that the effect of reweighting is negligible in the case of large volumes but it is sizeable when the volumes are small and the twisting angles are large. More importantly, we find that for un-improved Wilson fermions, and in small volumes, the dependence of the critical quark mass on the twisting angle is quite pronounced and results in large violations of the continuum dispersion relation.

  10. Subsidence Contours for South Louisiana; UTM 15N NAD83; LRA (2005); [subsidence_contours

    Data.gov (United States)

    Louisiana Geographic Information Center — The GIS data shapefile represents average subsidence contour intervals (0.02 cm/year over 10,000 years) for Coastal LA derived from the following: Kulp, M.A., 2000,...

  11. The finite element analysis and calculation of axial magnetic transition based on multi-twisting spindle%多倍捻锭子轴向磁力传动计算及其有限元分析

    Institute of Scientific and Technical Information of China (English)

    张智明; 梅顺齐; 肖人彬; 刘青松

    2011-01-01

    多倍捻锭子利用磁场作用力传递转矩,它的结构参数、永磁体分布影响磁力的大小变化,因此需要进行轴向磁力计算.针对轴向磁力传动结构,由经验求解法和等效磁荷原理建立磁力计算数学模型,采用有限元分析软件,通过仿真与计算,探讨磁力线、磁感应强度和磁场强度分布,研究不同计算方法时的磁转矩值,为轴向磁力传动结构优化设计和磁路分布提供依据,具有重要的实际应用价值.%The torque of multi-twisting spindle is transmitted by magnetic field.Calculation of axial magnetic force is necessary because of magnetic force varied with the spindle's structure parameters and permanent magnet distribution.The mathematic model is constructed with the experience solution and the principle of equivalent magnetic charge in view of the structure of axial magnetic transmitting.The ANSYS software is adopted for simulation and calculation of magnetic force to get the distribution of magnetic force linc,magnetic field intensity and magnetic flux intensity.These analysis benefit from the optimize design of axial magnetic transmitting machine and the permanent magnet distributing and is important practical applications.

  12. Local index formula and twisted spectral triples

    CERN Document Server

    Moscovici, Henri

    2009-01-01

    We prove a local index formula for a class of twisted spectral triples of type III modeled on the transverse geometry of conformal foliations with locally constant transverse conformal factor. Compared with the earlier proof of the untwisted case, the novel aspect resides in the fact that the twisted analogues of the JLO entire cocycle and of its retraction are no longer cocycles in their respective Connes bicomplexes. We show however that the passage to the infinite temperature limit, respectively the integration along the full temperature range against the Haar measure of the positive half-line, has the remarkable effect of curing in both cases the deviations from the cocycle identity.

  13. On Supermultiplet Twisting and Spin-Statistics

    Science.gov (United States)

    Hübsch, T.

    2013-10-01

    Twisting of off-shell supermultiplets in models with (1+1)-dimensional spacetime has been discovered in 1984, and was shown to be a generic feature of off-shell representations in worldline supersymmetry two decades later. It is shown herein that in all supersymmetric models with spacetime of four or more dimensions, this off-shell supermultiplet twisting, if nontrivial, necessarily maps regular (non-ghost) supermultiplets to ghost supermultiplets. This feature is shown to be ubiquitous in all fully off-shell supersymmetric models with (BV/BRST-treated) constraints.

  14. Multi-twist optical Mobius strips

    CERN Document Server

    Freund, Isaac

    2009-01-01

    Circularly polarized Gauss-Laguerre GL(0,0) and GL(0,1) laser beams that cross at their waists at a small angle are shown to generate a quasi-paraxial field that contains an axial line of circular polarization, a C line, surrounded by polarization ellipses whose major and minor axes generate multi-twist Mobius strips with twist numbers that increase with distance from the C point. These Mobius strips are interpreted in terms of Berry's phase for parallel transport of the ellipse axes around the C point.

  15. Effects Of Twist On Ceramic Threads

    Science.gov (United States)

    Sawko, Paul M.; Tran, Huy Kim

    1989-01-01

    Report describes study of effects of yarn twist and other manufacturing parameters on strength of ceramic sewing threads. Three types of thread considered; silica, aluminoborosilicate (ABS) with 14 percent boria, and ABS with 2 percent boria. For silica thread, best twist found 300 turns per meter. Produced highest break strength at temperatures up to about 540 degree C. Overall strengths of both ABS threads higher than silica thread. Threads used to stitch insulating blankets for reusable spacraft; must resist high temperatures and high aerodynamic loads of reentry into atmosphere of Earth.

  16. Spectral flows and twisted topological theories

    CERN Document Server

    Gato-Rivera, Beatriz; Gato-Rivera, Beatriz; Rosado, Jose Ignacio

    1995-01-01

    We analyze the action of the spectral flows on N=2 twisted topological theories. We show that they provide a useful mapping between the two twisted topological theories associated to a given N=2 superconformal theory. This mapping can also be viewed as a topological algebra automorphism. In particular null vectors are mapped into null vectors, considerably simplifying their computation. We give the level 2 results. Finally we discuss the spectral flow mapping in the case of the DDK and KM realizations of the topological algebra.

  17. A non-commuting twist in the partition function

    CERN Document Server

    Govindarajan, Suresh

    2012-01-01

    We compute a twisted index for an orbifold theory when the twist generating group does not commute with the orbifold group. The twisted index requires the theory to be defined on moduli spaces that are compatible with the twist. This is carried out for CHL models at special points in the moduli space where they admit dihedral symmetries. The commutator subgroup of the dihedral groups are cyclic groups that are used to construct the CHL orbifolds. The residual reflection symmetry is chosen to act as a `twist' on the partition function. The reflection symmetries do not commute with the orbifolding group and hence we refer to this as a non-commuting twist. We count the degeneracy of half-BPS states using the twisted partition function and find that the contribution comes mainly from the untwisted sector. We show that the generating function for these twisted BPS states are related to the Mathieu group M_{24}.

  18. Production and Perception of Contrast: The case of the rise-fall contour in German

    Directory of Open Access Journals (Sweden)

    Frank eKügler

    2015-09-01

    Full Text Available This study investigates the phonetics of German nuclear rise-fall contours in relation to contexts that trigger either a contrastive or a non-contrastive interpretation in the answer. A rise-fall contour can be conceived of a tonal sequence of L-H-L. A production study elicited target sentences in contrastive and non-contrastive contexts. The majority of cases realized showed a nuclear rise-fall contour. The acoustic analysis of these contours revealed a significant effect of contrastiveness on the height / alignment of the accent peak as a function of focus context. On the other hand, the height / alignment of the low turning point at the beginning of the rise did not show an effect of contrastiveness. In a series of semantic congruency perception tests participants judged the congruency of congruent and incongruent context-stimulus pairs based on three different sets of stimuli: (i original data, (ii manipulation of accent peak, and (iii manipulation of the leading low. Listeners distinguished nuclear rise-fall contours as a function of focus context (experiment 1 and 2, however not based on manipulations of the leading low (experiment 3. The results suggest that the alignment and scaling of the accentual peak are sufficient to license a contrastive interpretation of a nuclear rise-fall contour, leaving the rising part as a phonetic onglide, or as a low tone that does not interact with the contrastivity of the context.

  19. USGS Elevation Contours Overlay Map Service from The National Map

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — The USGS Elevation Contours service from The National Map (TNM) consists of contours generated for the conterminous United States from 1- and 1/3 arc-second...

  20. Automatic liver contouring for radiotherapy treatment planning

    Science.gov (United States)

    Li, Dengwang; Liu, Li; Kapp, Daniel S.; Xing, Lei

    2015-09-01

    To develop automatic and efficient liver contouring software for planning 3D-CT and four-dimensional computed tomography (4D-CT) for application in clinical radiation therapy treatment planning systems. The algorithm comprises three steps for overcoming the challenge of similar intensities between the liver region and its surrounding tissues. First, the total variation model with the L1 norm (TV-L1), which has the characteristic of multi-scale decomposition and an edge-preserving property, is used for removing the surrounding muscles and tissues. Second, an improved level set model that contains both global and local energy functions is utilized to extract liver contour information sequentially. In the global energy function, the local correlation coefficient (LCC) is constructed based on the gray level co-occurrence matrix both of the initial liver region and the background region. The LCC can calculate the correlation of a pixel with the foreground and background regions, respectively. The LCC is combined with intensity distribution models to classify pixels during the evolutionary process of the level set based method. The obtained liver contour is used as the candidate liver region for the following step. In the third step, voxel-based texture characterization is employed for refining the liver region and obtaining the final liver contours. The proposed method was validated based on the planning CT images of a group of 25 patients undergoing radiation therapy treatment planning. These included ten lung cancer patients with normal appearing livers and ten patients with hepatocellular carcinoma or liver metastases. The method was also tested on abdominal 4D-CT images of a group of five patients with hepatocellular carcinoma or liver metastases. The false positive volume percentage, the false negative volume percentage, and the dice similarity coefficient between liver contours obtained by a developed algorithm and a current standard delineated by the expert group

  1. Pulse contour-derived cardiac output in hemodialysis patients

    DEFF Research Database (Denmark)

    Cordtz, Joakim; Ladefoged, Soeren D

    2010-01-01

    Reliable methods for cardiac output determination are essential for studying the pathophysiology of intradialytic hypotension. Use of the current gold standard, the Transonic monitor, requires an arteriovenous fistula. We wished to verify the accuracy of a method based on finger pulse contour...... analysis, namely the Finometer monitor (FNM) for further use on patients dialyzing on a central vascular catheter. Fifty simultaneous cardiac output measurements were obtained during hemodialysis sessions in 25 patients. The internal variability of the FNM measurements was assessed by comparing 24 pairs...

  2. [External contour acquisition system for radiotherapy: an original solution].

    Science.gov (United States)

    Létourneau, D; Brochet, F; Bohémier, R; Gagnon, J

    2000-01-01

    A contour acquisition system has been designed in radiotherapy at the Sagamie Hospital complex (Chicoutimi, Québec) to measure the external contours of the patients who do not need a CT exam. This measuring system can produce transversal, sagittal or coronal patient contours in the treatment position. The absolute accuracy of the system is +/- 1 mm. The contours produced by this equipment can be transferred electronically or on paper to the planning system.

  3. On Twisting Real Spectral Triples by Algebra Automorphisms

    Science.gov (United States)

    Landi, Giovanni; Martinetti, Pierre

    2016-11-01

    We systematically investigate ways to twist a real spectral triple via an algebra automorphism and in particular, we naturally define a twisted partner for any real graded spectral triple. Among other things, we investigate consequences of the twisting on the fluctuations of the metric and possible applications to the spectral approach to the Standard Model of particle physics.

  4. On Twisting Real Spectral Triples by Algebra Automorphisms

    Science.gov (United States)

    Landi, Giovanni; Martinetti, Pierre

    2016-08-01

    We systematically investigate ways to twist a real spectral triple via an algebra automorphism and in particular, we naturally define a twisted partner for any real graded spectral triple. Among other things, we investigate consequences of the twisting on the fluctuations of the metric and possible applications to the spectral approach to the Standard Model of particle physics.

  5. ABOUT THE GEOMETRY AND THE APPLICATIONS OF THE TWISTED SURFACES

    Directory of Open Access Journals (Sweden)

    MÂRZA Carmen

    2015-06-01

    Full Text Available The helical and spiral surfaces are used in various fields. These surfaces are obtained by rotating a segment line called generatrix around directrices lines, respectively the spiral surfaces are obtained by composing simultaneously the movements of translation and rotation of a plane figure around an axis - which can be a straight line or a curved line, or around a real or imaginary surface - called core. After an overview of these surfaces, the attention of the authors will be focused on the geometrical and graphical analysis of the twisted surfaces in civil engineering branch, such as: columns, helical ramps and stairs, respectively buildings having a futuristic design.

  6. Edge and line oriented contour detection : State of the art

    NARCIS (Netherlands)

    Papari, Giuseppe; Petkov, Nicolai

    We present an overview of various edge and line oriented approaches to contour detection that have been proposed in the last two decades. By edge and line oriented we mean methods that do not rely on segmentation. Distinction is made between edges and contours. Contour detectors are divided in local

  7. Edge and line oriented contour detection : State of the art

    NARCIS (Netherlands)

    Papari, Giuseppe; Petkov, Nicolai

    2011-01-01

    We present an overview of various edge and line oriented approaches to contour detection that have been proposed in the last two decades. By edge and line oriented we mean methods that do not rely on segmentation. Distinction is made between edges and contours. Contour detectors are divided in local

  8. Craniosynostosis of coronal suture in twist1 mice occurs through endochondral ossification recapitulating the physiological closure of posterior frontal suture.

    Science.gov (United States)

    Behr, Björn; Longaker, Michael T; Quarto, Natalina

    2011-01-01

    Craniosynostosis, the premature closure of cranial suture, is a pathologic condition that affects 1/2000 live births. Saethre-Chotzen syndrome is a genetic condition characterized by craniosynostosis. The Saethre-Chotzen syndrome, which is defined by loss-of-function mutations in the TWIST gene, is the second most prevalent craniosynostosis. Although much of the genetics and phenotypes in craniosynostosis syndromes is understood, less is known about the underlying ossification mechanism during suture closure. We have previously demonstrated that physiological closure of the posterior frontal suture occurs through endochondral ossification. Moreover, we revealed that antagonizing canonical Wnt-signaling in the sagittal suture leads to endochondral ossification of the suture mesenchyme and sagittal synostosis, presumably by inhibiting Twist1. Classic Saethre-Chotzen syndrome is characterized by coronal synostosis, and the haploinsufficient Twist1(+/-) mice represents a suitable model for studying this syndrome. Thus, we seeked to understand the underlying ossification process in coronal craniosynostosis in Twist1(+/-) mice. Our data indicate that coronal suture closure in Twist1(+/-) mice occurs between postnatal day 9 and 13 by endochondral ossification, as shown by histology, gene expression analysis, and immunohistochemistry. In conclusion, this study reveals that coronal craniosynostosis in Twist1(+/-) mice occurs through endochondral ossification. Moreover, it suggests that haploinsufficiency of Twist1 gene, a target of canonical Wnt-signaling, and inhibitor of chondrogenesis, mimics conditions of inactive canonical Wnt-signaling leading to craniosynostosis.

  9. Craniosynostosis of coronal suture in Twist1+/- mice occurs through endochondral ossification recapitulating the physiological closure of posterior frontal suture

    Directory of Open Access Journals (Sweden)

    Bjorn eBehr

    2011-07-01

    Full Text Available Craniosynostosis, the premature closure of cranial suture, is a pathologic condition that affects 1/2000 live births. Saethre-Chotzen syndrome is a genetic condition characterized by craniosynostosis. The Saethre-Chotzen syndrome, which is defined by loss-of-function mutations in the TWIST gene, is the second most prevalent craniosynostosis. Although much of the genetics and phenotypes in craniosynostosis syndromes is understood, less is known about the underlying ossification mechanism during suture closure. We have previously demonstrated that physiological closure of the posterior frontal (PF suture occurs through endochondral ossification. Moreover, we revealed that antagonizing canonical Wnt signaling in the sagittal suture leads to endochondral ossification of the suture mesenchyme and sagittal synostosis, presumably by inhibiting Twist1. Classic Saethre-Chotzen syndrome is characterized by coronal synostosis, and the haploinsufficient Twist1+/- mice represents a suitable model for studying this syndrome. Thus, we seeked to understand the underlying ossification process in coronal craniosynostosis in Twist1+/- mice. Our data indicate that coronal suture closure in Twist1+/- mice occurs between postnatal day 9 to 13 by endochondral ossification, as shown by histology, gene expression analysis and immunohistochemistry. In conclusion, this study reveals that coronal craniosynostosis in Twist1+/- mice occurs through endochondral ossification. Moreover, it suggests that haploinsufficency of Twist1 gene, a target of canonical Wnt-signaling, and inhibitor of chondrogenesis, mimics conditions of inactive canonical Wnt-signaling leading to craniosynostosis.

  10. Human Lips-Contour Recognition and Tracing

    Directory of Open Access Journals (Sweden)

    Md. Hasan Tareque

    2014-01-01

    Full Text Available Human-lip detection is an important criterion for many automated modern system in present day. Like computerized speech reading, face recognition etc. system can work more precisely if human-lip can detect accurately. There are many processes for detecting human-lip. In this paper an approach is developed so that the region of a human-lip can be detected, we called it lip contour. For this a region-based Active Contour Model (ACM is introduced with watershed segmentation. In this model we used global energy terms instead of local energy terms because, global energy gives better convergence rate for malicious environment. At the time of ACM initialization by using H8 based on Lyapunov stability theory, the system gives more accurate and stable result.

  11. Maintaining Contour Trees of Dynamic Terrains

    DEFF Research Database (Denmark)

    Agarwal, Pankaj K.; Mølhave, Thomas; Revsbæk, Morten

    2015-01-01

    We study the problem of maintaining the contour tree T of a terrain Sigma, represented as a triangulated xy-monotone surface, as the heights of its vertices vary continuously with time. We characterize the combinatorial changes in T and how they relate to topological changes in Sigma. We present...... a kinetic data structure (KDS) for maintaining T efficiently. It maintains certificates that fail, i.e., an event occurs, only when the heights of two adjacent vertices become equal or two saddle vertices appear on the same contour. Assuming that the heights of two vertices of Sigma become equal only O(1......) times and these instances can be computed in O(1) time, the KDS processes O(kappa + n) events, where n is the number of vertices in Sigma and kappa is the number of events at which the combinatorial structure of T changes, and processes each event in O(log n) time. The KDS can be extended to maintain...

  12. Twisting singular solutions of Bethe's equations

    CERN Document Server

    Nepomechie, Rafael I

    2014-01-01

    The Bethe equations for the periodic XXX and XXZ spin chains admit singular solutions, for which the corresponding eigenvalues and eigenvectors are ill-defined. We use a twist regularization to derive conditions for such singular solutions to be physical, in which case they correspond to genuine eigenvalues and eigenvectors of the Hamiltonian.

  13. Disconnected Loops with Twisted Mass Lattice QCD

    CERN Document Server

    Wilcox, W; Morgan, R; Lewis, R; Wilcox, Walter; Darnell, Dean; Morgan, Ron; Lewis, Randy

    2005-01-01

    We give a general introduction and discussion of the issues involved in using the twisted mass formulation of lattice fermions in the context of disconnected loop calculations, including a short orientation on the present experimental situation for nucleon strange quark form factors. A prototype calculation of the disconnected part of the nucleon scalar form factor is described.

  14. Phase diagram of twisted mass lattice QCD

    Science.gov (United States)

    Sharpe, Stephen R.; Wu, Jackson M.

    2004-11-01

    We use the effective chiral Lagrangian to analyze the phase diagram of two-flavor twisted mass lattice QCD as a function of the normal and twisted masses, generalizing previous work for the untwisted theory. We first determine the chiral Lagrangian including discretization effects up to next-to-leading order (NLO) in a combined expansion in which m2π/(4πfπ)2˜aΛ (a being the lattice spacing, and Λ=ΛQCD). We then focus on the region where m2π/(4πfπ)2˜(aΛ)2, in which case competition between leading and NLO terms can lead to phase transitions. As for untwisted Wilson fermions, we find two possible phase diagrams, depending on the sign of a coefficient in the chiral Lagrangian. For one sign, there is an Aoki phase for pure Wilson fermions, with flavor and parity broken, but this is washed out into a crossover if the twisted mass is nonvanishing. For the other sign, there is a first order transition for pure Wilson fermions, and we find that this transition extends into the twisted mass plane, ending with two symmetrical second order points at which the mass of the neutral pion vanishes. We provide graphs of the condensate and pion masses for both scenarios, and note a simple mathematical relation between them. These results may be of importance to numerical simulations.

  15. HOMOCLINIC TWIST BIFURCATIONS WITH Z(2) SYMMETRY

    NARCIS (Netherlands)

    ARONSON, DG; VANGILS, SA; KRUPA, M

    1994-01-01

    We analyze bifurcations occurring in the vicinity of a homoclinic twist point for a generic two-parameter family of Z2 equivariant ODEs in four dimensions. The results are compared with numerical results for a system of two coupled Josephson junctions with pure capacitive load.

  16. Redefining B twisted topological sigma models

    NARCIS (Netherlands)

    Jonghe, F. de; Termonia, P.; Troost, W.; Vandoren, S.

    2007-01-01

    The recently proposed procedure to perform the topological B-twist in rigid N = 2 models is applied to the case of the o model on a Kähler manifold. This leads to an alternative description of Witten’s topological o model, which allows for a proper BRST interpretation and ghost number assignement. W

  17. Generalized Weyl modules for twisted current algebras

    Science.gov (United States)

    Makedonskyi, I. A.; Feigin, E. B.

    2017-08-01

    We introduce the notion of generalized Weyl modules for twisted current algebras. We study their representation-theoretic and combinatorial properties and also their connection with nonsymmetric Macdonald polynomials. As an application, we compute the dimension of the classical Weyl modules in the remaining unknown case.

  18. Energy Release in Driven Twisted Coronal Loops

    Science.gov (United States)

    Bareford, M. R.; Gordovskyy, M.; Browning, P. K.; Hood, A. W.

    2016-01-01

    We investigate magnetic reconnection in twisted magnetic fluxtubes, representing coronal loops. The main goal is to establish the influence of the field geometry and various thermodynamic effects on the stability of twisted fluxtubes and on the size and distribution of heated regions. In particular, we aim to investigate to what extent the earlier idealised models, based on the initially cylindrically symmetric fluxtubes, are different from more realistic models, including the large-scale curvature, atmospheric stratification, thermal conduction and other effects. In addition, we compare the roles of Ohmic heating and shock heating in energy conversion during magnetic reconnection in twisted loops. The models with straight fluxtubes show similar distribution of heated plasma during the reconnection: it initially forms a helical shape, which subsequently becomes very fragmented. The heating in these models is rather uniformly distributed along fluxtubes. At the same time, the hot plasma regions in curved loops are asymmetric and concentrated close to the loop tops. Large-scale curvature has a destabilising influence: less twist is needed for instability. Footpoint convergence normally delays the instability slightly, although in some cases, converging fluxtubes can be less stable. Finally, introducing a stratified atmosphere gives rise to decaying wave propagation, which has a destabilising effect.

  19. Contours, contours 500 ft, Published in 2008, 1:24000 (1in=2000ft) scale, Box Elder County.

    Data.gov (United States)

    NSGIC GIS Inventory (aka Ramona) — This Contours dataset, published at 1:24000 (1in=2000ft) scale, was produced all or in part from Other information as of 2008. It is described as 'contours 500 ft'....

  20. Contours, ft 10 NED contours 2, Published in 2008, 1:24000 (1in=2000ft) scale, Box Elder County.

    Data.gov (United States)

    NSGIC GIS Inventory (aka Ramona) — This Contours dataset, published at 1:24000 (1in=2000ft) scale, was produced all or in part from Other information as of 2008. It is described as 'ft 10 NED contours...

  1. Contours, contours 100 ft, Published in 2008, 1:24000 (1in=2000ft) scale, Box Elder County.

    Data.gov (United States)

    NSGIC GIS Inventory (aka Ramona) — This Contours dataset, published at 1:24000 (1in=2000ft) scale, was produced all or in part from Other information as of 2008. It is described as 'contours 100 ft'....

  2. Contours, contours_2ft, Published in 2007, 1:1200 (1in=100ft) scale, Dodge County, Wisconsin.

    Data.gov (United States)

    NSGIC GIS Inventory (aka Ramona) — This Contours dataset, published at 1:1200 (1in=100ft) scale, was produced all or in part from LIDAR information as of 2007. It is described as 'contours_2ft'. Data...

  3. Contours, ft 10 NED contours 1, Published in 2008, 1:24000 (1in=2000ft) scale, Box Elder County.

    Data.gov (United States)

    NSGIC GIS Inventory (aka Ramona) — This Contours dataset, published at 1:24000 (1in=2000ft) scale, was produced all or in part from Other information as of 2008. It is described as 'ft 10 NED contours...

  4. Contours, Tagged Vector Contours obtained from DASC, Published in 2003, 1:24000 (1in=2000ft) scale, Reno County.

    Data.gov (United States)

    NSGIC GIS Inventory (aka Ramona) — This Contours dataset, published at 1:24000 (1in=2000ft) scale as of 2003. It is described as 'Tagged Vector Contours obtained from DASC'. Data by this publisher...

  5. Contours, contour 500 ft, Published in 2009, 1:24000 (1in=2000ft) scale, Washington County.

    Data.gov (United States)

    NSGIC GIS Inventory (aka Ramona) — This Contours dataset, published at 1:24000 (1in=2000ft) scale, was produced all or in part from Other information as of 2009. It is described as 'contour 500 ft'....

  6. Contours, contour 50 ft, Published in 2009, 1:24000 (1in=2000ft) scale, Washington County.

    Data.gov (United States)

    NSGIC GIS Inventory (aka Ramona) — This Contours dataset, published at 1:24000 (1in=2000ft) scale, was produced all or in part from Other information as of 2009. It is described as 'contour 50 ft'....

  7. Contours, contour 10 ft, Published in 2009, 1:24000 (1in=2000ft) scale, Washington County.

    Data.gov (United States)

    NSGIC GIS Inventory (aka Ramona) — This Contours dataset, published at 1:24000 (1in=2000ft) scale, was produced all or in part from Other information as of 2009. It is described as 'contour 10 ft'....

  8. Body Image and Body Contouring Procedures.

    Science.gov (United States)

    Sarwer, David B; Polonsky, Heather M

    2016-10-01

    Dissatisfaction with physical appearance and body image is a common psychological phenomena in Western society. Body image dissatisfaction is frequently reported by those who have excess body weight, but also is seen in those of normal body weight. For both groups of individuals, this dissatisfaction impacts self-esteem and quality of life. Furthermore, it is believed to be the motivational catalyst to a range of appearance-enhancing behaviors, including weight loss efforts and physical activity. Body image dissatisfaction is also believed to play a role in the decision to seek the wide range of body contouring procedures offered by aesthetic physicians. Individuals who seek these procedures typically report increased body image dissatisfaction, focus on the feature they wish to alter with treatment, and often experience improvement in body image following treatment. At the same time, extreme body image dissatisfaction is a symptom of a number of recognized psychiatric disorders. These include anorexia nervosa, bulimia nervosa, and body dysmorphic disorder (BDD), all of which can contraindicate aesthetic treatment. This special topic review paper provides an overview of the relationship between body image dissatisfaction and aesthetic procedures designed to improve body contouring. The review specifically focuses on the relationship of body image and body weight, as well as the presentation of body image psychopathology that would contraindicate aesthetic surgery. The overall goal of the paper is to highlight the clinical implications of the existing research and provide suggestions for future research on the psychological aspects of body contouring procedures.

  9. Contour Estimation by Array Processing Methods

    Directory of Open Access Journals (Sweden)

    Bourennane Salah

    2006-01-01

    Full Text Available This work is devoted to the estimation of rectilinear and distorted contours in images by high-resolution methods. In the case of rectilinear contours, it has been shown that it is possible to transpose this image processing problem to an array processing problem. The existing straight line characterization method called subspace-based line detection (SLIDE leads to models with orientations and offsets of straight lines as the desired parameters. Firstly, a high-resolution method of array processing leads to the orientation of the lines. Secondly, their offset can be estimated by either the well-known method of extension of the Hough transform or another method, namely, the variable speed propagation scheme, that belongs to the array processing applications field. We associate it with the method called "modified forward-backward linear prediction" (MFBLP. The signal generation process devoted to straight lines retrieval is retained for the case of distorted contours estimation. This issue is handled for the first time thanks to an inverse problem formulation and a phase model determination. The proposed method is initialized by means of the SLIDE algorithm.

  10. Dynamic Active Contours for Visual Tracking.

    Science.gov (United States)

    Niethammer, Marc; Tannenbaum, Allen; Angenent, Sigurd

    2006-01-01

    Visual tracking using active contours is usually set in a static framework. The active contour tracks the object of interest in a given frame of an image sequence. A subsequent prediction step ensures good initial placement for the next frame. This approach is unnatural; the curve evolution gets decoupled from the actual dynamics of the objects to be tracked. True dynamical approaches exist, all being marker particle based and thus prone to the shortcomings of such particle-based implementations. In particular, topological changes are not handled naturally in this framework. The now classical level set approach is tailored for evolutions of manifolds of codimension one. However, dynamic curve evolution is at least a codimension two problem. We propose an efficient, level set based approach for dynamic curve evolution, which addresses the artificial separation of segmentation and prediction while retaining all the desirable properties of the level set formulation. It is based on a new energy minimization functional which, for the first time, puts dynamics into the geodesic active contour framework.

  11. Higher Twist Distribution Amplitudes of the Nucleon in QCD

    CERN Document Server

    Braun, V M; Mahnke, N; Stein, E

    2000-01-01

    We present the first systematic study of higher-twist light-cone distribution amplitudes of the nucleon in QCD. We find that the valence three-quark state is described at small transverse separations by eight independent distribution amplitudes. One of them is leading twist-3, three distributions are twist-4 and twist-5, respectively, and one is twist-6. A complete set of distribution amplitudes is constructed, which satisfies equations of motion and constraints that follow from conformal expansion. Nonperturbative input parameters are estimated from QCD sum rules.

  12. VT 10 ft Contour Lines generated from bare earth lidar - Chittenden

    Data.gov (United States)

    Vermont Center for Geographic Information — (Link to Metadata) ElevationContours_CN10T (10ft contours) was extracted from ElevationContours_CN2T (2ft contours), which was generated by USGS from the 2004...

  13. Context modulates the ERP signature of contour integration.

    Directory of Open Access Journals (Sweden)

    Bart Machilsen

    Full Text Available We investigated how the electrophysiological signature of contour integration is changed by the context in which a contour is embedded. Specifically, we manipulated the orientations of Gabor elements surrounding an embedded shape outline. The amplitudes of early visual components over posterior scalp regions were changed by the presence of a contour, and by the orientation of elements surrounding the contour. Differences in context type had an effect on the early P1 and N1 components, but not on the later P2 component. The presence of a contour had an effect on the N1 and P2 components, but not on the earlier P1 component. A modulatory effect of context on contour integration was observed on the N1 component. These results highlight the importance of the context in which contour integration takes place.

  14. Incorporating Prior Shape into Geometric Active Contours for Face Contour Detection

    Institute of Scientific and Technical Information of China (English)

    HUANGFuzhen; SUJianbo; XIYugeng

    2004-01-01

    In this paper a new method that incorporates prior shape information into geometric active contours for face contour detection is proposed. As in general a human face can be treated as an ellipse with a little shape variation, the prior face shape is represented as an elliptical curve. By combining the prior face shape with the powerful geometric active model proposed by Chan and Vese, the improved geometric active model can retain all the advantage of the Chan-Vese model and can detect face contours in images with complex backgrounds accurately even if the image is noisy. Moreover, by implementing the new model in a variational level set framework, automatic topological changes of the model can be achieved naturally and the transformation parameters that map the face boundary to the prior shape can be roughly estimated simultaneously. The experimental results show our procedure to be eiTicient.

  15. Three-dimensional adult male head and skull contours.

    Science.gov (United States)

    Lee, Calvin; Loyd, Andre M; Nightingale, Roger; Myers, Barry S; Damon, Andrew; Bass, Cameron R

    2014-01-01

    Traumatic brain injury (TBI) is a major public health issue, affecting millions of people annually. Anthropomorphic test devices (ATDs) and finite element models (FEMs) provide a means of understanding factors leading to TBI, potentially reducing the occurrence. Thus, there is a need to ensure that these tools accurately model humans. For example, the Hybrid III was not based on 3-dimensional human head shape data. The objective of this study is to produce average head and skull contours for an average U.S. male that can be used for ATDs and FEMs. Computed tomography (CT) scans of adult male heads were obtained from a database provided by the University of Virginia Center for Applied Biomechanics. An orthographic viewer was used to extract head and skull contours from the CT scans. Landmarks were measured graphically using HyperMesh (Altair, HyperWorks). To determine the head occipital condyle (OC) centroid, surface meshes of the OCs were made and the centroid of the surfaces was calculated. The Hybrid III contour was obtained using a MicroScribe Digitizer (Solution Technologies, Inc., Oella, MD). Comparisons of the average male and ATD contours were performed using 2 methods: (1) the midsagittal and midcoronal ATD contours relative to the OC centroid were compared to the corresponding 1 SD range of the average male contours; (2) the ATD sagittal contour was translated relative to the average male sagittal contour to minimize the area between the 2 contours. Average male head and skull contours were created. Landmark measurements were made for the dorsum sellae, nasion skin, nasion bone, infraorbital foramen, and external auditory meatus, all relative to the OC centroid. The Hybrid III midsagittal contour was outside the 1 SD range for 15.2 percent of the average male head contour but only by a maximum distance of 1.5 mm, whereas the Hybrid III midcoronal head contour was outside the 1 SD range for 12.2 percent of the average male head contour by a maximum distance

  16. Dynamic investigation of twist-bend coupling in a wind turbine blade

    DEFF Research Database (Denmark)

    Luczak, M.; Manzato, S.; Peeters, B.;

    2011-01-01

    This paper presents some results and aspects of the multidisciplinary and interdisciplinary research oriented for the experimental and numerical study in static and dynamic domains on the bend-twist coupling in the full scale section of a wind turbine blade structure. The main goal of the conducted...... research is to confirm experimentally the numerical prediction of modification of the dynamic and static properties of a wind turbine blade. The bend-twist coupling was implemented by adding angled UD (UniDirectional) layers on the suction and pressure side of the blade. Static and dynamic tests were...... performed on a section of the full scale wind turbine blade provided by VestasWind Systems A/S. The results are presented and compared with the measurements of the original and modified blade. Comparison analysis confirmed that UD layers introduce measurable bend-twist couplings, which was not present...

  17. Dynamic investigation of twist-bend coupling in a wind turbine blade

    DEFF Research Database (Denmark)

    Luczak, M.; Manzato, S.; Peeters, B.

    2011-01-01

    This paper presents some results and aspects of the multidisciplinary and interdisciplinary research oriented for the experimental and numerical study in static and dynamic domains on the bend-twist coupling in the full scale section of a wind turbine blade structure. The main goal of the conducted...... research is to confirm experimentally the numerical prediction of modification of the dynamic and static properties of a wind turbine blade. The bend-twist coupling was implemented by adding angled UD (UniDirectional) layers on the suction and pressure side of the blade. Static and dynamic tests were...... performed on a section of the full scale wind turbine blade provided by VestasWind Systems A/S. The results are presented and compared with the measurements of the original and modified blade. Comparison analysis confirmed that UD layers introduce measurable bend-twist couplings, which was not present...

  18. Synthesis and structural determination of twisted MoS{sub 2} nanotubes

    Energy Technology Data Exchange (ETDEWEB)

    Santiago, P.; Schabes-Retchkiman, P. [Instituto de Fisica, Universidad Nacional Autonoma de Mexico, Apartado Postal 20-364, 01000, Mexico, D.F. (Mexico); Ascencio, J.A. [Instituto Mexicano del Petroleo, Eje Central Lazaro Cardenas 152, C.P. 07730, Mexico, D.F., Col. San Bartolo Atepehuacan (Mexico); Facultad de Quimica, Universidad Autonoma del Estado de Mexico, Paseo Colon esq. Paseo Tollocan, Apartado Postal A-20, C.P. 50120, Toluca (Mexico); Mendoza, D. [Instituto de Investigaciones en Materiales, Universidad Nacional Autonoma de Mexico, Apartado Postal 70-360, 04510, Mexico, D.F. (Mexico); Perez-Alvarez, M. [Instituto Nacional de Investigaciones Nucleares, Km. 36.5 Carr, Mexico-Toluca Ocoyoacac (Mexico); Espinosa, A. [Instituto de Fisica, Universidad Nacional Autonoma de Mexico, Apartado Postal 20-364, 01000, Mexico, D.F. (Mexico); Facultad de Ciencias VAEMEX, 50000, Toloca, Edo Mex. (Mexico); Reza-SanGerman, C. [Instituto de Fisica, Universidad Nacional Autonoma de Mexico, Apartado Postal 20-364, 01000, Mexico, D.F. (Mexico); Facultad de Quimica, Universidad Autonoma del Estado de Mexico, Paseo Colon esq. Paseo Tollocan, Apartado Postal A-20, C.P. 50120, Toluca (Mexico); Instituto Nacional de Investigaciones Nucleares, Km. 36.5 Carr, Mexico-Toluca Ocoyoacac (Mexico); Camacho-Bragado, G.A. [Department of Chemical Engineering, CNM and TMI, University of Texas at Austin, 78712, Austin, TX (United States); Jose-Yacaman, M. [Instituto de Fisica, Universidad Nacional Autonoma de Mexico, Apartado Postal 20-364, 01000, Mexico, D.F. (Mexico); Department of Chemical Engineering, CNM and TMI, University of Texas at Austin, 78712, Austin, TX (United States)

    2004-03-01

    In the present work we report the synthesis of MoS{sub 2} nanotubes with diameters greater than 10 nm using a template method. The length and properties of these nanotubes are a direct result of the preparation method. High-resolution transmission electron microscopy is used to study the structure of these highly curved entities. Molecular dynamics simulations of MoS{sub 2} nanotubes reveal that one of the stable forms of the nanotubes is a twisted one. The twisting of the nanotubes produces a characteristic contrast in the images, which is also studied using simulation methods. The analysis of the local contrast close to the perpendicular orientation shows geometrical arrays of dots in domain-like structures, which are demonstrated to be a product of the atomic overlapping of irregular curvatures in the nanotubes. The configuration of some of the experimentally obtained nanotubes is demonstrated to be twisted with a behavior suggesting partial plasticity. (orig.)

  19. Investigation on Twisting and Side Wall Opening Occurring in Curved Hat Channel Products Made of High Strength Steel Sheets

    Science.gov (United States)

    Takamura, Masato; Fukui, Ayako; Yano, Hiroshi; Hama, Takayuki; Sunaga, Hideyuki; Makinouchi, Akitake; Asakawa, Motoo

    2011-08-01

    High strength steel sheets are becoming increasingly important for the weight reduction of automotive bodies to meet the requirements for reduced environmental impact. However, dimensional defects resulting from springback are serious issues, and effective methods of predicting and reducing such defects are necessary. In this study, we numerically and experimentally analyzed the mechanisms of dimensional inaccuracies caused by springback occurring in curved hat channel deep drawing products. The analysis was based on the static explicit FEM software "TP-STRUCT" (the solver part is known as "STAMP3D"). The results of the experiments and simulations similarly show that the twist angle is positive (right-hand system) when the drawing height is relatively large. We calculated the twist torque around the longitudinal axis using the stress distributions obtained by FE analysis. Through the investigation of twist torque and its transition during the drawing and die removal processes, we found that the negative torque generated by side wall opening occurring in the die removal process is the dominant factor of the positive twist. Knowing such mechanisms of twist in cases with a relatively large drawing height, we attempted to explore methods of reducing side wall opening by giving the side wall a stepped shape with the eventual aim of reducing twist. Consequently, we concluded that the stepped shape on the side wall has marked effects of reducing side wall opening, mainly through the elimination of bending-unbending effects on die shoulders, which was verified by observing the stress distribution obtained by FE analysis.

  20. Slow twists of solar magnetic flux tubes and the polar magnetic field of the sun

    Science.gov (United States)

    Hollweg, Joseph V.; Lee, Martin A.

    1989-01-01

    The solar wind model of Weber and Davis (1967) is generalized to compute the heliospheric magnetic field resulting from solar rotation or a steady axisymmetric twist including a geometrical expansion which is more rapid than spherical. The calculated increase in the ratio of the toroidal to poloidal field components with heliocentric radial distance r clarifies an expression derived recently by Jokipii and Kota (1989). Magnetic-field components transverse to r do not in general grow to dominate the radial component at large r. The analysis also yields expressions for the Poynting flux associated with the steady twists.

  1. Impact of region contouring variability on image-based focal therapy evaluation

    Science.gov (United States)

    Gibson, Eli; Donaldson, Ian A.; Shah, Taimur T.; Hu, Yipeng; Ahmed, Hashim U.; Barratt, Dean C.

    2016-03-01

    Motivation: Focal therapy is an emerging low-morbidity treatment option for low-intermediate risk prostate cancer; however, challenges remain in accurately delivering treatment to specified targets and determining treatment success. Registered multi-parametric magnetic resonance imaging (MPMRI) acquired before and after treatment can support focal therapy evaluation and optimization; however, contouring variability, when defining the prostate, the clinical target volume (CTV) and the ablation region in images, reduces the precision of quantitative image-based focal therapy evaluation metrics. To inform the interpretation and clarify the limitations of such metrics, we investigated inter-observer contouring variability and its impact on four metrics. Methods: Pre-therapy and 2-week-post-therapy standard-of-care MPMRI were acquired from 5 focal cryotherapy patients. Two clinicians independently contoured, on each slice, the prostate (pre- and post-treatment) and the dominant index lesion CTV (pre-treatment) in the T2-weighted MRI, and the ablated region (post-treatment) in the dynamic-contrast- enhanced MRI. For each combination of clinician contours, post-treatment images were registered to pre-treatment images using a 3D biomechanical-model-based registration of prostate surfaces, and four metrics were computed: the proportion of the target tissue region that was ablated and the target:ablated region volume ratio for each of two targets (the CTV and an expanded planning target volume). Variance components analysis was used to measure the contribution of each type of contour to the variance in the therapy evaluation metrics. Conclusions: 14-23% of evaluation metric variance was attributable to contouring variability (including 6-12% from ablation region contouring); reducing this variability could improve the precision of focal therapy evaluation metrics.

  2. Automated Contour Detection for Intravascular Ultrasound Image Sequences Based on Fast Active Contour Algorithm

    Institute of Scientific and Technical Information of China (English)

    DONG Hai-yan; WANG Hui-nan

    2006-01-01

    Intravascular ultrasound can provide high-resolution real-time crosssectional images about lumen, plaque and tissue. Traditionally, the luminal border and medial-adventitial border are traced manually. This process is extremely timeconsuming and the subjective difference would be large. In this paper, a new automated contour detection method is introduced based on fast active contour model.Experimental results found that lumen and vessel area measurements after automated detection showed good agreement with manual tracings with high correlation coefficients (0.94 and 0.95, respectively) and small system difference ( -0.32 and 0.56, respectively). So it can be a reliable and accurate diagnostic tool.

  3. General relativistic neutron stars with twisted magnetosphere

    CERN Document Server

    Pili, A G; Del Zanna, L

    2014-01-01

    Soft Gamma-Ray Repeaters and Anomalous X-Ray Pulsars are extreme manifestations of the most magnetized neutron stars: magnetars. The phenomenology of their emission and spectral properties strongly support the idea that the magnetospheres of these astrophysical objects are tightly twisted in the vicinity of the star. Previous studies on equilibrium configurations have so far focused on either the internal or the external magnetic field configuration, without considering a real coupling between the two fields. Here we investigate numerical equilibrium models of magnetized neutron stars endowed with a confined twisted magnetosphere, solving the general relativistic Grad-Shafranov equation both in the interior and in the exterior of the compact object. A comprehensive study of the parameters space is provided to investigate the effects of different current distributions on the overall magnetic field structure.

  4. Twisted black hole is Taub-NUT

    Science.gov (United States)

    Ong, Yen Chin

    2017-01-01

    Recently a purportedly novel solution of the vacuum Einstein field equations was discovered: it supposedly describes an asymptotically flat twisted black hole in 4-dimensions whose exterior spacetime rotates in a peculiar manner—the frame dragging in the northern hemisphere is opposite from that of the southern hemisphere, which results in a globally vanishing angular momentum. Furthermore it was shown that the spacetime has no curvature singularity. We show that the geometry of this black hole spacetime is nevertheless not free of pathological features. In particular, it harbors a rather drastic conical singularity along the axis of rotation. In addition, there exist closed timelike curves due to the fact that the constant r and constant t surfaces are not globally Riemannian. In fact, none of these are that surprising since the solution is just the Taub-NUT geometry. As such, despite the original claim that the twisted black hole might have observational consequences, it cannot be.

  5. Magnetic Field Twisting by Intergranular Downdrafts

    Science.gov (United States)

    Taroyan, Youra; Williams, Thomas

    2016-10-01

    The interaction of an intergranular downdraft with an embedded vertical magnetic field is examined. It is demonstrated that the downdraft may couple to small magnetic twists leading to an instability. The descending plasma exponentially amplifies the magnetic twists when it decelerates with depth due to increasing density. Most efficient amplification is found in the vicinity of the level, where the kinetic energy density of the downdraft reaches equipartition with the magnetic energy density. Continual extraction of energy from the decelerating plasma and growth in the total azimuthal energy occurs as a consequence of the wave-flow coupling along the downdraft. The presented mechanism may drive vortices and torsional motions that have been detected between granules and in simulations of magnetoconvection.

  6. Tinkertoys for the Twisted D-Series

    CERN Document Server

    Chacaltana, Oscar; Trimm, Anderson

    2013-01-01

    We study 4D N=2 superconformal field theories that arise from the compactification of 6D N=(2,0) theories of type D_N on a Riemann surface, in the presence of punctures twisted by a Z_2 outer automorphism. Unlike the untwisted case, the family of SCFTs is in general parametrized, not by M_{g,n}, but by a branched cover thereof. The classification of these SCFTs is carried out explicitly in the case of the D_4 theory, in terms of three-punctured spheres and cylinders, and we provide tables of properties of twisted punctures for the D_5 and D_6 theories. We find realizations of Spin(8) and Spin(7) gauge theories with matter in all combinations of vector and spinor representations with vanishing beta-function, as well as Sp(3) gauge theories with matter in the 3-index traceless antisymmetric representation.

  7. Valve-aided twisted Savonius rotor

    Energy Technology Data Exchange (ETDEWEB)

    Jaya Rajkumar, M.; Saha, U.K.

    2006-05-15

    Accessories, such as end plates, deflecting plates, shielding and guide vanes, may increase the power of a Savonius rotor, but make the system structurally complex. In such cases, the rotor can develop a relatively large torque at small rotational speeds and is cheap to build, however it harnesses only a small fraction of the incident wind energy. Another proposition for increasing specific output is to place non-return valves inside the concave side of the blades. Such methods have been studied experimentally with a twisted-blade Thus improving a Savonius rotor's energy capture. This new concept has been named as the 'Valve-Aided Twisted Savonius'rotor. Tests were conducted in a low-speed wind tunnel to evaluate performance. This mechanism is found to be independent of flow direction, and shows potential for large machines. [Author].

  8. Hybrid antenna synthesis for reconfigurable contoured beams

    Science.gov (United States)

    Searle, A. D.; Westcott, B. S.

    1993-08-01

    A reflector illuminated by a small phased array is an attractive antenna configuration for systems requiring reconfigurable contoured beams. The use of a shaped reflector can provide control of the feed power distribution and antenna geometry. A systematic reflector synthesis technique based on geometric optics is formulated, using complex coordinate notation and illustrated by application to a simple design requirement. Results demonstrate that geometric shaping can be successfully applied to systems with distributed sources, and that significant beam reconfiguration can be achieved by phase-only control of the feed array.

  9. Overlap fermions on a twisted mass sea

    CERN Document Server

    Bär, O; Schäefer, S; Scorzato, L; Shindler, A

    2006-01-01

    We present first results of a mixed action project. We analyze gauge configurations generated with two flavors of dynamical twisted mass fermions. Neuberger's overlap Dirac operator is used for the valence sector. The various choices in the setup of the simulation are discussed. We employ chiral perturbation theory to describe the effects of using different actions in the sea and valence sector at non-zero lattice spacing.

  10. DNA Packaging in Bacteriophage: Is Twist Important?

    OpenAIRE

    Spakowitz, Andrew James; Wang, Zhen-Gang

    2005-01-01

    We study the packaging of DNA into a bacteriophage capsid using computer simulation, specifically focusing on the potential impact of twist on the final packaged conformation. We perform two dynamic simulations of packaging a polymer chain into a spherical confinement: one where the chain end is rotated as it is fed, and one where the chain is fed without end rotation. The final packaged conformation exhibits distinct differences in these two cases: the packaged conformation from feeding with...

  11. On rectangular HOMFLY for twist knots

    CERN Document Server

    Kononov, Ya

    2016-01-01

    As a new step in the study of rectangularly-colored knot polynomials, we reformulate the prescription of arXiv:1606.06015 for twist knots in the double-column representations $R=[rr]$ in terms of skew Schur polynomials. These, however, are mysteriously shifted from the standard topological locus, what makes further generalization to arbitrary $R=[r^s]$ not quite straightforward.

  12. Ferromagnetic nanoparticles suspensions in twisted nematic

    Science.gov (United States)

    Cîrtoaje, Cristina; Petrescu, Emil; Stan, Cristina; Creangă, Dorina

    2016-05-01

    Ferromagnetic nanoparticles insertions in nematic liquid crystals (NLC) in twisted configuration are studied and a theoretical model is proposed to explain the results. Experimental observation revealed that nanoparticles tend to overcrowd in long strings parallel to the rubbing direction of the alignment substrate of the LC cell. Their behavior under external field was studied and their interaction with their nematic host is described using elastic continuum theory.

  13. Twisted Radiation by Electrons in Spiral Motion

    CERN Document Server

    Katoh, M; Mirian, N S; Konomi, T; Taira, Y; Kaneyasu, T; Hosaka, M; Yamamoto, N; Mochihashi, A; Takashima, Y; Kuroda, K; Miyamoto, A; Miyamoto, K; Sasaki, S

    2016-01-01

    We theoretically show that a single free electron in circular/spiral motion radiates an electromagnetic wave possessing helical phase structure and carrying orbital angular momentum. We experimentally demonstrate it by double-slit diffraction on radiation from relativistic electrons in spiral motion. We show that twisted photons should be created naturally by cyclotron/synchrotron radiations or Compton scatterings in various situations in astrophysics. We propose promising laboratory vortex photon sources in various wavelengths ranging from radio wave to gamma-rays.

  14. Evaluation of solar mirror figure by moire contouring

    Energy Technology Data Exchange (ETDEWEB)

    Griffin, J.W.; Lind, M.A.

    1980-06-01

    Moire topography is applied to the figure assessment of solar mirrors. The technique is demonstrated on component facets of a six-meter diameter, four-meter focal length, parabolic dish collector. The relative ease of experimental implementation and subsequent data analysis suggests distinct advantages over the more established laser ray trace or BCS/ICS technique for many applications. The theoretical and experimental considerations necessary to fully implement moire topography on mirror surfaces are detailed. A procedure to de-specularize the mirror is demonstrated which conserves the surface morphology without damaging the reflective surface. The moire fringe patterns observed for the actual mirror facets are compared with theoretical contours generated for representative dish facets using a computer simulation algorithm. A method for evaluating the figure error of the real facet is presented in which the error parameter takes the form of an average absolute deviation of the surface slope from theoretical. The experimental measurement system used for this study employs a 200 line/inch Ronchi transmission grating. The mirror surface is illuminated by a collimated beam at 60/sup 0/. The fringe observation is performed normal to the grating. These parameters yield contour intervals for the fringe patterns of 0.073 mm. The practical considerations for extending the techniques to higher resolution are discussed.

  15. Twisted spectral geometry for the standard model

    CERN Document Server

    Martinetti, Pierre

    2015-01-01

    The Higgs field is a connection one-form as the other bosonic fields, provided one describes space no more as a manifold M but as a slightly non-commutative generalization of it. This is well encoded within the theory of spectral triples: all the bosonic fields of the standard model - including the Higgs - are obtained on the same footing, as fluctuations of a generalized Dirac operator by a matrix-value algebra of functions on M. In the commutative case, fluctuations of the usual free Dirac operator by the complex-value algebra A of smooth functions on M vanish, and so do not generate any bosonic field. We show that imposing a twist in the sense of Connes-Moscovici forces to double the algebra A, but does not require to modify the space of spinors on which it acts. This opens the way to twisted fluctuations of the free Dirac operator, that yield a perturbation of the spin connection. Applied to the standard model, a similar twist yields in addition the extra scalar field needed to stabilize the electroweak v...

  16. ELECTRICALLY FORCED VIBRATION OF A THICKNESS-TWIST MODE PIEZOELECTRIC RESONATOR WITH NON-UNIFORM ELECTRODES

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    We study the effect of electrodes with varying thickness on thickness-twist vibration of a piezoelectric plate resonator of crystals of 6 mm symmetry. An exact theoretical analysis is performed. Results show that non-uniform electrodes have a strong effect on mode shapes, and suggest the possibility of using nonuniform electrodes for strong energy trapping.

  17. Modified super twisting controller for servicing to uncontrolled spacecraft

    Institute of Scientific and Technical Information of China (English)

    Binglong Chen; Yunhai Geng

    2015-01-01

    A relative position and attitude coupled sliding mode control er is proposed by combining the standard super twisting (ST) control and basic linear algorithm for autonomous rendezvous and docking. It is schemed for on-orbit servicing to a tumbling non-cooperative target spacecraft subjected to external disturbances. A coupled dynamic model is established including both kinemati-cal and dynamic coupled effect of relative rotation on relative translation, which il ustrates the relative movement between the docking port located in target spacecraft and another in service spacecraft. The modified super twisting (MST) control algorithm containing linear compensation items is schemed to manipulate the relative position and attitude synchronously. The correction provides more robustness and convergence velocity for dealing with linearly growing perturbations than the ST control algorithm. Moreover, the stability characteristic of closed-loop system is ana-lyzed by Lyapunov method. Numerical simulations are adopted to verify the analysis with the comparison between MST and ST control algorithms. Simulation results demonstrate that the pro-posed MST control er is characterized by high precision, strong robustness and fast convergence velocity to attenuate the linearly increasing perturbations.

  18. Atomic ionization by twisted photons: Angular distribution of emitted electrons

    CERN Document Server

    Matula, Oliver; Serbo, Valeriy G; Surzhykov, Andrey; Fritzsche, Stephan

    2013-01-01

    We investigate the angular distribution of electrons that are emitted in the ionization of hydrogen-like ions by twisted photons. Analysis is performed based on the first-order perturbation theory and the non-relativistic Schr\\"odinger equation. Special attention is paid to the dependence of the electron emission pattern on the impact parameter b of the ion with respect to the centre of the twisted wave front. In order to explore such a dependence, detailed calculations were carried out for the photoionization of the 1s ground and 2 py excited states of neutral hydrogen atoms. Based on these calculations, we argue that for relatively small impact parameters the electron angular distributions may be strongly affected by altering the position of the atom within the wave front. In contrast, if the atom is placed far from the front centre, the emission pattern of the electrons is independent on the impact parameter b and resembles that observed in the photoionization by plane wave photons.

  19. Alar Contour Grafts in Rhinoplasty: A Safe and Reproducible Way to Refine Alar Contour Aesthetics.

    Science.gov (United States)

    Unger, Jacob G; Roostaeian, Jason; Small, Kevin H; Pezeshk, Ronnie A; Lee, Michael R; Harris, Ryan; Rohrich, Rod J

    2016-01-01

    Alar rim deformities such as retraction, notching, collapse, and asymmetry are common problems in rhinoplasty patients. Although alar rim deformities may be improved through rhinoplasty, this area is prone to late changes because of scarring of the soft triangles and a paucity of native structural support. The purpose of this study was to analyze the effect of alar contour grafts on primary rhinoplasty. Fifty consecutive primary rhinoplasty patients with preoperative and postoperative photographs who received alar contour grafts were evaluated for alar aesthetics; 50 consecutive primary rhinoplasty patients without such grafts served as controls. Differences among alar retraction, notching, collapse, and asymmetry from anterior, lateral, and basal views were evaluated. Follow-up ranged from 1 to 4 years and was graded on a four-point scale. The average difference between the two groups' aggregate preoperative scores was 0.21 (p = 0.24). The average preoperative and postoperative scores in the nongraft group were significant for worsening retraction, notching, and collapse but insignificant for asymmetry. The preoperative and postoperative scores for the graft group were insignificant for retraction but improved significantly for notching, collapse, and asymmetry. Postoperatively, the aggregate average of the scores in the nongroup was 0.32 points worse (p Alar contour grafts have a clear and important impact on cosmetic results of primary rhinoplasty. Use of alar contour grafts has been shown to improve aesthetics, whereas there is a worsening of the measured parameters postoperatively without use of these grafts. Therapeutic, III.

  20. What is in a contour map? A region-based logical formalization of contour semantics

    Science.gov (United States)

    Usery, E. Lynn; Hahmann, Torsten

    2015-01-01

    Contours maps (such as topographic maps) compress the information of a function over a two-dimensional area into a discrete set of closed lines that connect points of equal value (isolines), striking a fine balance between expressiveness and cognitive simplicity. They allow humans to perform many common sense reasoning tasks about the underlying function (e.g. elevation).

  1. Study fidelity spatial contours of industrial robots

    Directory of Open Access Journals (Sweden)

    A. V. Ivanova

    2014-01-01

    Full Text Available The purpose of this paper to identify deviations fidelity spatial contours of industrial robots, determine the error pattern detected, and define the ways to solve the problem.The paper presents the research results of fidelity spatial contours done by Fanuc M- 710iC/50 industrial robot when moving along a predetermined path. The proposed method uses a QC20-W ballbar wireless system of Renishaw company, designed to diagnose the state of the measurement and playback linear and angular displacements of the CNC.The solutions to adapt the QC20-W ballbar system to the constructive peculiarities of industrial robots with five or more independently controlled axes are given. The stages of the preparation of diagnostic systems and software robot movements are described.According to study results of errors that arise while playing back the programmed motions of a fixed point of robot capture in three mutually perpendicular planes its practical accuracy has been defined when performing movements in a given region of the working area, thereby allowing us, eventually, to draw a conclusion on the possibility to use a robot in one technological process or another.The study has resulted in emerging the guidelines for the operation of industrial robots with five or more independently controlled axes. Using these guidelines enables us to increase the playback accuracy of the industrial robot to 0.01 mm.

  2. Contoured tank outlets for draining of cylindrical tanks in low-gravity environment. [Lewis Research Center Zero Gravity Facility

    Science.gov (United States)

    Symons, E. P.

    1979-01-01

    An analysis is presented for defining the outlet contour of a hemispherical-bottomed cylindrical tank that will prevent vapor ingestion when the tank is drained. The analysis was used to design two small-scale tanks that were fabricated and then tested in a low gravity environment. The draining performance of the tanks was compared with that for a tank with a conventional outlet having a constant circular cross-sectional area, under identical conditions. Even when drained at off-design conditions, the contoured tank had less liquid residuals at vapor ingestion than the conventional outlet tank. Effects of outflow rate, gravitational environment, and fluid properties on the outlet contour are discussed. Two potential applications of outlet contouring are also presented and discussed.

  3. Contour Detection and Completion for Inpainting and Segmentation Based on Topological Gradient and Fast Marching Algorithms

    Directory of Open Access Journals (Sweden)

    Didier Auroux

    2011-01-01

    Full Text Available We combine in this paper the topological gradient, which is a powerful method for edge detection in image processing, and a variant of the minimal path method in order to find connected contours. The topological gradient provides a more global analysis of the image than the standard gradient and identifies the main edges of an image. Several image processing problems (e.g., inpainting and segmentation require continuous contours. For this purpose, we consider the fast marching algorithm in order to find minimal paths in the topological gradient image. This coupled algorithm quickly provides accurate and connected contours. We present then two numerical applications, to image inpainting and segmentation, of this hybrid algorithm.

  4. Using Multi-Modal 3D Contours and Their Relations for Vision and Robotics

    DEFF Research Database (Denmark)

    Baseski, Emre; Pugeault, Nicolas; Kalkan, Sinan

    2010-01-01

    In this work, we make use of 3D contours and relations between them (namely, coplanarity, cocolority, distance and angle) for four different applications in the area of computer vision and vision-based robotics. Our multi-modal contour representation covers both geometric and appearance information....... We show the potential of reasoning with global entities in the context of visual scene analysis for driver assistance, depth prediction, robotic grasping and grasp learning. We argue that, such 3D global reasoning processes complement widely-used 2D local approaches such as bag-of-features since 3D...

  5. The variable expressivity and incomplete penetrance of the twist-null heterozygous mouse phenotype resemble those of human Saethre-Chotzen syndrome.

    Science.gov (United States)

    Bourgeois, P; Bolcato-Bellemin, A L; Danse, J M; Bloch-Zupan, A; Yoshiba, K; Stoetzel, C; Perrin-Schmitt, F

    1998-06-01

    Most targeted gene mutations are recessive and analyses of gene function often focus on homozygous mutant phenotypes. Here we describe parts of the expression pattern of M-twist in the head of developing wild-type mice and present our analysis of the phenotype of heterozygous twist- null animals at around birth and in adults. A number of twist -null heterozygous mice present skull and limb defects and, in addition, we observed other malformations, such as defects in middle ear formation and the xyphoïd process. Our study is of interest to understand bone formation and the role of M-twist during this process, as within the same animal growth of some bones can be accelerated while for others it can be delayed. Moreover, we show here that expressivity of the mouse mutant heterozygous phenotype is dependent on the genetic background. This information might also be helpful for clinicians, since molecular defects affecting one allele of the human H-twist ( TWIST ) gene were identified in patients affected with Saethre-Chotzen syndrome (SCS). Expressivity of this syndrome is variable, although most patients present craniofacial and limb malformations resembling those seen in mutant mice. Thus the mutant mouse twist -null strain might be a useful animal model for SCS. The twist -null mutant mouse model, combined with other mutant mouse strains, might also help in an understanding of the etiology of morphological abnormalities that appear in human patients affected by other syndromes.

  6. Interrelationship of cranial suture fusion, basicranial development, and resynostosis following suturectomy in twist1(+/-) mice, a murine model of Saethre-Chotzen syndrome.

    Science.gov (United States)

    Hermann, Christopher D; Lee, Christopher S D; Gadepalli, Siddharth; Lawrence, Kelsey A; Richards, Megan A; Olivares-Navarrete, Rene; Williams, Joseph K; Schwartz, Zvi; Boyan, Barbara D

    2012-10-01

    The interrelationships among suture fusion, basicranial development, and subsequent resynostosis in syndromic craniosynostosis have yet to be examined. The objectives of this study were to determine the potential relationship between suture fusion and cranial base development in a model of syndromic craniosynostosis and to assess the effects of the syndrome on resynostosis following suturectomy. To do this, posterior frontal and coronal suture fusion, postnatal development of sphenooccipital synchondrosis, and resynostosis in Twist1(+/+) (WT) and Twist1(+/-) litter-matched mice (a model for Saethre-Chotzen syndrome) were quantified by evaluating μCT images with advanced image-processing algorithms. The coronal suture in Twist(+/-) mice developed, fused, and mineralized at a faster rate than that in normal littermates at postnatal days 6-30. Moreover, premature fusion of the coronal suture in Twist1(+/-) mice preceded alterations in cranial base development. Analysis of synchondrosis showed faster mineralization in Twist(+/-) mice at postnatal days 25-30. In a rapid resynostosis model, there was an inability to fuse both the midline posterior frontal suture and craniotomy defects in 21-day-old Twist(+/-) mice, despite having accelerated mineralization in the posterior frontal suture and defects. This study showed that dissimilarities between Twist1(+/+) and Twist1(+/-) mice are not limited to a fused coronal suture but include differences in fusion of other sutures, the regenerative capacity of the cranial vault, and the development of the cranial base.

  7. Predictive Modeling of Complex Contoured Composite Structures Project

    Data.gov (United States)

    National Aeronautics and Space Administration — The existing HDWLT (pictured) contoured composite structure design, its analyses and manufacturing tools, will be used to validate key analyses inputs through...

  8. A new algorithm of brain volume contours segmentation

    Institute of Scientific and Technical Information of China (English)

    吴建明; 施鹏飞

    2003-01-01

    This paper explores brain CT slices segmentation technique and some related problems, including contours segmentation algorithms, edge detector, algorithm evaluation and experimental results. This article describes a method for contour-based segmentation of anatomical structures in 3D medical data sets. With this method, the user manually traces one or more 2D contours of an anatomical structure of interest on parallel planes arbitrarily cutting the data set. The experimental results showes the segmentation based on 3D brain volume and 2D CT slices. The main creative contributions in this paper are: (1) contours segmentation algorithm; (2) edge detector; (3) algorithm evaluation.

  9. Effects of Spatial Frequency Similarity and Dissimilarity on Contour Integration.

    Directory of Open Access Journals (Sweden)

    Malte Persike

    Full Text Available We examined the effects of spatial frequency similarity and dissimilarity on human contour integration under various conditions of uncertainty. Participants performed a temporal 2AFC contour detection task. Spatial frequency jitter up to 3.0 octaves was applied either to background elements, or to contour and background elements, or to none of both. Results converge on four major findings. (1 Contours defined by spatial frequency similarity alone are only scarcely visible, suggesting the absence of specialized cortical routines for shape detection based on spatial frequency similarity. (2 When orientation collinearity and spatial frequency similarity are combined along a contour, performance amplifies far beyond probability summation when compared to the fully heterogenous condition but only to a margin compatible with probability summation when compared to the fully homogenous case. (3 Psychometric functions are steeper but not shifted for homogenous contours in heterogenous backgrounds indicating an advantageous signal-to-noise ratio. The additional similarity cue therefore not so much improves contour detection performance but primarily reduces observer uncertainty about whether a potential candidate is a contour or just a false positive. (4 Contour integration is a broadband mechanism which is only moderately impaired by spatial frequency dissimilarity.

  10. Twisted exponential sums of polynomials in one variable

    Institute of Scientific and Technical Information of China (English)

    2010-01-01

    The twisted T-adic exponential sums associated to a polynomial in one variable are studied.An explicit arithmetic polygon in terms of the highest two exponents of the polynomial is proved to be a lower bound of the Newton polygon of the C-function of the twisted T-adic exponential sums.This bound gives lower bounds for the Newton polygon of the L-function of twisted p-power order exponential sums.

  11. Negative Regulatory Role of TWIST1 on SNAIL Gene Expression.

    Science.gov (United States)

    Forghanifard, Mohammad Mahdi; Ardalan Khales, Sima; Farshchian, Moein; Rad, Abolfazl; Homayouni-Tabrizi, Masoud; Abbaszadegan, Mohammad Reza

    2017-01-01

    Epithelial-mesenchymal transition (EMT) is crucial for specific morphogenetic movements during embryonic development as well as pathological processes of tumor cell invasion and metastasis. TWIST and SNAIL play vital roles in both developmental and pathological EMT. Our aim in this study was to investigate the functional correlation between TWIST1 and SNAIL in human ESCC cell line (KYSE-30). The packaging cell line GP293T was cotransfected with either control retroviral pruf-IRES-GFP plasmid or pruf-IRES-GFP-hTWIST1 and pGP plasmid. The KYSE-30 ESCC cells were transduced with produced viral particles and examined with inverted fluorescence microscope. DNA was extracted from transduced KYSE-30 cells and analyzed for copy number of integrated retroviral sequences in the target cell genome. The concentration of retroviral particles was determined by Real-time PCR. After RNA extraction and cDNA synthesis, the mRNA expression of TWIST1 and SNAIL was assessed by comparative real-time PCR amplification. Ectopic expression of TWIST1 in KYSE-30, dramatically reduces SNAIL expression. Retroviral transduction enforced TWIST1 overexpression in GFP-hTWIST1 nearly 9 folds in comparison with GFP control cells, and interestingly, this TWIST1 enforced expression caused a - 7 fold decrease of SNAIL mRNA expression in GFP-hTWIST1 compared to GFP control cells. Inverse correlation of TWIST1 and SNAIL mRNA levels may introduce novel molecular gene expression pathway controlling EMT process during ESCC aggressiveness and tumorigenesis. Consequently, these data extend the spectrum of biological activities of TWIST1 and propose that therapeutic repression of TWIST1 may be an effective strategy to inhibit cancer cell invasion and metastasis.

  12. Numerical investigation into the unsteady effects of non-axisymmetric turbine endwall contouring on secondary flows

    CSIR Research Space (South Africa)

    Dunn, Dwain I

    2011-08-01

    Full Text Available oscillations. Thus there could be a greater advantage to contouring blade rows downstream to the first rotor; however this remains to be investigated. It was found that the computed efficiencies of the unsteady and the steady state analysis were different...

  13. A twist tale of cancer metastasis and tumor angiogenesis.

    Science.gov (United States)

    Tseng, Jen-Chieh; Chen, Hsiao-Fan; Wu, Kou-Juey

    2015-11-01

    Twist1 is an evolutionally conserved transcription factor. Originally identified in Drosophila as a key regulator for mesoderm development, it was later implicated in many human diseases, including Saethre-Chotzen syndrome and cancer. Twist1's involvement in cancer has been well recognized. Driven by hypoxia-induced factor-1 (HIF-1), Twist1 has been considered as a proto-oncogene and its overexpression has been observed in a wide variety of human cancers. High expression level of Twist1 is closely related to tumor aggressiveness and metastatic potential. In cancer cells, Twist1 has been shown to function as a key regulator of epithelial-mesenchymal transition (EMT), a critical process for metastasis initiation. Twist1 has also been implicated in maintaining cancer stemness for self-renewal and chemoresistance. This review first summarizes the roles of Twist1 in embryo development and Saethre-Chotzen syndrome followed by a discussion of Twist1's critical functions in cancer. In particular, the review focuses on the recent discovery of Twist1's capability to promote endothelial transdifferentiation of cancer cells beyond EMT.

  14. Twist1 activity thresholds define multiple functions in limb development

    OpenAIRE

    Krawchuk, Dayana; Weiner, Shoshana J; Chen, You-Tzung; Lu, Benson; Costantini, Frank; Behringer, Richard R.; Laufer, Ed

    2010-01-01

    The basic helix-loop-helix transcription factor Twist1 is essential for normal limb development. Twist1−/− embryos die at midgestation. However, studies on early limb buds found that Twist1−/− mutant limb mesenchyme has an impaired response to FGF signaling from the apical ectodermal ridge, which disrupts the feedback loop between the mesenchyme and AER, and reduces and shifts anteriorly Shh expression in the zone of polarizing activity. We have combined Twist1 null, hypomorph and conditional...

  15. Nematic twist cell: Strong chirality induced at the surfaces

    Science.gov (United States)

    Lin, Tzu-Chieh; Nemitz, Ian R.; Pendery, Joel S.; Schubert, Christopher P. J.; Lemieux, Robert P.; Rosenblatt, Charles

    2013-04-01

    A nematic twist cell having a thickness gradient was filled with a mixture containing a configurationally achiral liquid crystal (LC) and chiral dopant. A chiral-based linear electrooptic effect was observed on application of an ac electric field. This "electroclinic effect" varied monotonically with d, changing sign at d =d0 where the chiral dopant exactly compensated the imposed twist. The results indicate that a significant chiral electrooptic effect always exists near the surfaces of a twist cell containing molecules that can be conformationally deracemized. Additionally, this approach can be used to measure the helical twisting power (HTP) of a chiral dopant in a liquid crystal.

  16. Optical Möbius strips and twisted ribbon cloaks.

    Science.gov (United States)

    Freund, Isaac

    2014-02-15

    Optical Möbius strips that surround points of circular polarization, C points, in a generic three-dimensional optical field are cloaked by lines of twisted ribbons attached to the C points. When cloaking occurs, the observable signed twist index that counts the number of half-twists (one or three), and also measures the handedness (right or left), of a generic Möbius strip is determined by the twisted ribbon cloaks. Although some cloaks can be detached, they can never all be removed.

  17. Twisted rudder for reducing fuel-oil consumption

    Directory of Open Access Journals (Sweden)

    Kim Jung-Hun

    2014-09-01

    Full Text Available Three twisted rudders fit for large container ships have been developed; 1 the Z-twisted rudder that is an asymmetry type taking into consideration incoming flow angles of the propeller slipstream, 2 the ZB-twisted rudder with a rudder bulb added onto the Z-twisted rudder, and 3 the ZB-F twisted rudder with a rudder fin attached to the ZB-twisted rudder. The twisted rudders have been designed computationally with the hydrodynamic characteristics in a self-propulsion condition in mind. The governing equation is the Navier-Stokes equations in an unsteady turbulent flow. The turbulence model applied is the Reynolds stress. The calculation was carried out in towing and self-propulsion conditions. The sliding mesh technique was employed to simulate the flow around the propeller. The speed performances of the ship with the twisted rudders were verified through model tests in a towing tank. The twisted versions showed greater performance driven by increased hull efficiency from less thrust deduction fraction and more effective wake fraction and decreased propeller rotating speed

  18. Finite-dimensional representations of twisted hyper loop algebras

    CERN Document Server

    Bianchi, Angelo

    2012-01-01

    We investigate the category of finite-dimensional representations of twisted hyper loop algebras, i.e., the hyperalgebras associated to twisted loop algebras over finite-dimensional simple Lie algebras. The main results are the classification of the irreducible modules, the definition of the universal highest-weight modules, called the Weyl modules, and, under a certain mild restriction on the characteristic of the ground field, a proof that the simple modules and the Weyl modules for the twisted hyper loop algebras are isomorphic to appropriate simple and Weyl modules for the non-twisted hyper loop algebras, respectively, via restriction of the action.

  19. Modelling of Nonthermal Microwave Emission From Twisted Magnetic Loops

    CERN Document Server

    Sharykin, I N

    2016-01-01

    Microwave gyrosynchrotron radio emission generated by nonthermal electrons in twisted magnetic loops is modelled using the recently developed simulation tool GX Simulator. We consider isotropic and anisotropic pitch-angle distributions. The main scope of the work is to understand impact of the magnetic field twisted topology on resulted radio emission maps. We have found that nonthermal electrons inside twisted magnetic loops produce gyrosynchrotron radio emission with peculiar polarization distribution. The polarization sign inversion line is inclined relatively to the axis of the loop. Radio emission source is more compact in the case of less twisted loop, considering anisotropic pitch-angle distribution of nonthermal electrons.

  20. Design, Manufacture and Testing of A Bend-Twist D-Spar

    Energy Technology Data Exchange (ETDEWEB)

    Ong, Cheng-Huat; Tsai, Stephen W.

    1999-06-01

    Studies have indicated that an adaptive wind turbine blade design can significantly enhance the performance of the wind turbine blade on energy capture and load mitigation. In order to realize the potential benefits of aeroelastic tailoring, a bend-twist D-spar, which is the backbone of a blade, was designed and fabricated to achieve the objectives of having maximum bend-twist coupling and fulfilling desirable structural properties (031 & GJ). Two bend-twist D-spars, a hybrid of glass and carbon fibers and an all-carbon D-spar, were fabricated using a bladder process. One of the D-spars, the hybrid D-spar, was subjected to a cantilever static test and modal testing. Various parameters such as materials, laminate schedule, thickness and internal rib were examined in designing a bend-twist D-spar. The fabrication tooling, the lay-up process and the joint design for two symmetric clamshells are described in this report. Finally, comparisons between the experimental test results and numerical results are presented. The comparisons indicate that the numerical analysis (static and modal analysis) agrees well with test results.

  1. India-Pakistan: Contours of Relationship

    Directory of Open Access Journals (Sweden)

    Devika Mittal

    2016-06-01

    Full Text Available Even after about 70 years of separation, India and Pakistan continue to live in the prison of the past. The rhetoric of partition is still alive in the memory of the people of both the countries. They have constructed fixed, unchanging and competing images for each other. While Pakistan became an Islamic Republic, India adopted secularism, thereby, negating the two-nation theory. The ‘differences’ along with memories of partition has made Indian and Pakistani to remain in permanent hostile situation. The leaders of the two countries try to settle their disputes but fails because of lack of support from their social and political institutions. Since its coming into power in 2014, the NDA government under the Indian Prime Minister, Mr. Narendra Modi has managed to engage the Pakistani establishment, despite many problems between the two countries. This article tries to highlight upon the contours of relationships post-2014.

  2. CMOS image sensor with contour enhancement

    Science.gov (United States)

    Meng, Liya; Lai, Xiaofeng; Chen, Kun; Yuan, Xianghui

    2010-10-01

    Imitating the signal acquisition and processing of vertebrate retina, a CMOS image sensor with bionic pre-processing circuit is designed. Integration of signal-process circuit on-chip can reduce the requirement of bandwidth and precision of the subsequent interface circuit, and simplify the design of the computer-vision system. This signal pre-processing circuit consists of adaptive photoreceptor, spatial filtering resistive network and Op-Amp calculation circuit. The adaptive photoreceptor unit with a dynamic range of approximately 100 dB has a good self-adaptability for the transient changes in light intensity instead of intensity level itself. Spatial low-pass filtering resistive network used to mimic the function of horizontal cell, is composed of the horizontal resistor (HRES) circuit and OTA (Operational Transconductance Amplifier) circuit. HRES circuit, imitating dendrite of the neuron cell, comprises of two series MOS transistors operated in weak inversion region. Appending two diode-connected n-channel transistors to a simple transconductance amplifier forms the OTA Op-Amp circuit, which provides stable bias voltage for the gate of MOS transistors in HRES circuit, while serves as an OTA voltage follower to provide input voltage for the network nodes. The Op-Amp calculation circuit with a simple two-stage Op-Amp achieves the image contour enhancing. By adjusting the bias voltage of the resistive network, the smoothing effect can be tuned to change the effect of image's contour enhancement. Simulations of cell circuit and 16×16 2D circuit array are implemented using CSMC 0.5μm DPTM CMOS process.

  3. 扭曲椭圆管换热器的数值模拟及场协同分析%Numerical Simulation and Field Synergy Analysis of Twisted Oval Tube Heat Exchanger

    Institute of Scientific and Technical Information of China (English)

    朱冬生; 石仲璟; 钱泰磊; 谭祥辉; 肖静美

    2015-01-01

    In order to analyze the effects of geometrical parameters on heat transfer, pressure drop performance and field synergy of both tube side and shell side in twisted oval tube heat exchanger, as well as the convective heat transfer of twisted oval tube heat exchangers with different geometrical parameters, were simulated with Fluent 6.3.26. A user defined function (UDF) was also designed to calculate the included angle between the temperature field and the velocity field, which is referred as field synergy angle. The results show that: (1) Realizablek-εmodel is relatively better than Standard k-εmodel and RNG k-εmodel for the fields simulation of both sides of the tubes in the twisted oval tube heat exchanger. The difference of calculatedNu andf with experimental results are both less than 5%. (2) The heat transfer factor and friction factor are in proportion to axial ratio of the oval tube and in inverse proportion to torque both on tube side and shell side in twisted oval tube heat exchanger. (3) Based on field synergy principle, synergy angle does not change significantly withRe. However, the twisted tubes with different geometrical parameters have different synergy angle on both sides of the tube. The secondary flow optimizes both temperature and velocity distribution, thus the angle between the velocity and temperature field is reduced and heat transfer is enhanced.%为了分析换热管几何参数对扭曲椭圆管换热器管程和壳程的传热与压降性能以及场协同关系的影响,今运用Fluent 6.3.26对不同几何参数的扭曲椭圆管换热器的管内和管外对流传热进行了数值模拟,并编写UDF程序计算温度场与速度场的夹角,即场协同角。结果表明: Realizablek-ε模型相对更好地模拟出扭曲椭圆管换热器管内和管外的流场和温度场,努赛尔数 Nu 以及摩擦系数 f 与实验结果的差别都在5%以内。在扭曲椭圆管换热器的管程和壳程, Nu和f都随着扭曲

  4. Identifying same-cell contours in image stacks: a key step in making 3D reconstructions.

    Science.gov (United States)

    Leung, Tony Kin Shun; Veldhuis, Jim H; Krens, S F Gabby; Heisenberg, C P; Brodland, G Wayne

    2011-02-01

    Identification of contours belonging to the same cell is a crucial step in the analysis of confocal stacks and other image sets in which cell outlines are visible, and it is central to the making of 3D cell reconstructions. When the cells are close packed, the contour grouping problem is more complex than that found in medical imaging, for example, because there are multiple regions of interest, the regions are not separable from each other by an identifiable background and regions cannot be distinguished by intensity differences. Here, we present an algorithm that uses three primary metrics-overlap of contour areas in adjacent images, co-linearity of the centroids of these areas across three images in a stack, and cell taper-to assign cells to groups. Decreasing thresholds are used to successively assign contours whose membership is less obvious. In a final step, remaining contours are assigned to existing groups by setting all thresholds to zero and groups having strong hour-glass shapes are partitioned. When applied to synthetic data from isotropic model aggregates, a curved model epithelium in which the long axes of the cells lie at all possible angles to the transection plane, and a confocal image stack, algorithm assignments were between 97 and 100% accurate in sets having at least four contours per cell. The algorithm is not particularly sensitive to the thresholds used, and a single set of parameters was used for all of the tests. The algorithm, which could be extended to time-lapse data, solves a key problem in the translation of image data into cell information.

  5. Equilibrium shapes of twisted magnetic filaments

    Energy Technology Data Exchange (ETDEWEB)

    Belovs, Mihails; Cirulis, Teodors; Cebers, Andrejs [University of Latvia, Zellu 8, LV-1002 (Latvia)], E-mail: aceb@tesla.sal.lv

    2009-06-12

    It is shown that ferromagnetic filaments with free and unclamped ends undergo buckling instabilities under the action of twist. Solutions of nonlinear equations describing the buckled shapes are found, and it is shown that the transition to the buckled shape is subcritical if the magnetization is parallel to the field and supercritical when the magnetization of the straight filament is opposite to the external field. Solutions with the localized curvature distribution are found in the case of long filaments. The class of solutions corresponding to helices is described, and the behavior of coiled ferromagnetic and superparamagnetic filaments is compared.

  6. Non-destructive identification of twisted light.

    Science.gov (United States)

    Li, Pengyun; Wang, Bo; Song, Xinbing; Zhang, Xiangdong

    2016-04-01

    The non-destructive identification of the orbital angular momentum (OAM) is essential to various applications in the optical information processing. Here, we propose and demonstrate experimentally an efficient method to identify non-destructively the OAM by using a modified Mach-Zehnder interferometer. Our schemes are applicable not only to the case with integer charges, but also to optical vortices with noninteger charges. Our Letter presents the first experimental demonstration of the non-destructive identification of twisted light with integer or noninteger topological charges, which has potential applications in the OAM-based data transmission for optical communications.

  7. Instanton corrections to twist-two operators

    CERN Document Server

    Alday, Luis F

    2016-01-01

    We present the calculation of the leading instanton contribution to the scaling dimensions of twist-two operators with arbitrary spin and to their structure constants in the OPE of two half-BPS operators in $\\mathcal N=4$ SYM. For spin-two operators we verify that, in agreement with $\\mathcal N=4$ superconformal Ward identities, the obtained expressions coincide with those for the Konishi operator. For operators with high spin we find that the leading instanton correction vanishes. This arises as the result of a rather involved calculation and requires a better understanding.

  8. A role for fibroblast growth factor receptor-2 in the altered osteoblast phenotype induced by Twist haploinsufficiency in the Saethre-Chotzen syndrome.

    Science.gov (United States)

    Guenou, Hind; Kaabeche, Karim; Mée, Sandrine Le; Marie, Pierre J

    2005-06-01

    Genetic mutations of Twist, a bHLH transcription factor, induce premature fusion of cranial sutures (craniosynostosis) in the Saethre-Chotzen syndrome (SCS). The mechanisms by which Twist haploinsufficiency may alter osteoblast differentiation are poorly understood. In this study, we investigated the role of fibroblast growth factor receptor-2 (Fgfr2) in the abnormal osteoblast differentiation in SCS. Cranial osteoblasts from an SCS patient with a Y103X mutation inducing deletion of the Twist bHLH domain showed decreased Fgfr2 mRNA levels associated with decreased expression of Runx2, bone sialoprotein (BSP) and osteocalcin (OC), markers of differentiated osteoblasts, compared with wild-type osteoblasts. Transfection with Twist or Runx2 expression vectors, but not with Runx2 mutant which impairs DNA binding, restored Fgfr2, Runx2, BSP and OC expression in Twist mutant osteoblasts. EMSA analysis of mutant osteoblast nuclear extracts showed reduced Runx2 binding to a target OSE2 site in the Fgfr2 promoter. ChIP analyses showed that both Twist and Runx2 in mutant osteoblast nuclear extracts bind to a specific region in the Fgfr2 promoter. Significantly, forced expression of Fgfr2 restored Runx2 and osteoblast marker genes, whereas a dominant-negative Fgfr2 further decreased Runx2 and downstream genes in Twist mutant osteoblasts, indicating that alteration of Fgfr2 results in downregulation of osteoblast genes in Twist mutant osteoblasts. We conclude that Twist haploinsufficiency downregulates Fgfr2 mRNA expression, which in turn reduces Runx2 and downstream osteoblast-specific genes in human calvarial osteoblasts. This provides genetic and biochemical evidence for a role of Fgfr2 in the altered osteoblast phenotype induced by Twist haploinsufficiency in the SCS.

  9. 32 CFR 707.5 - Underway replenishment contour lights.

    Science.gov (United States)

    2010-07-01

    ... 32 National Defense 5 2010-07-01 2010-07-01 false Underway replenishment contour lights. 707.5... RULES WITH RESPECT TO ADDITIONAL STATION AND SIGNAL LIGHTS § 707.5 Underway replenishment contour lights... underway replenishment operations, either red or blue lights at delivery-ship-deck-edge extremities....

  10. A bit-level systolic array for digital contour smoothing

    NARCIS (Netherlands)

    Petkov, Nikolai; Sloboda, Fridrich

    1989-01-01

    Linear operators for digital contour smoothing are described. These operators are defined by circulant Toeplitz matrices and allow to smooth digital contours in the least-squares sense. They minimize the undersampling, digitizing and quantizing error and allow to calculate invariants, such as curvat

  11. Compressing industrial computed tomography images by means of contour coding

    Science.gov (United States)

    Jiang, Haina; Zeng, Li

    2013-10-01

    An improved method for compressing industrial computed tomography (CT) images is presented. To have higher resolution and precision, the amount of industrial CT data has become larger and larger. Considering that industrial CT images are approximately piece-wise constant, we develop a compression method based on contour coding. The traditional contour-based method for compressing gray images usually needs two steps. The first is contour extraction and then compression, which is negative for compression efficiency. So we merge the Freeman encoding idea into an improved method for two-dimensional contours extraction (2-D-IMCE) to improve the compression efficiency. By exploiting the continuity and logical linking, preliminary contour codes are directly obtained simultaneously with the contour extraction. By that, the two steps of the traditional contour-based compression method are simplified into only one. Finally, Huffman coding is employed to further losslessly compress preliminary contour codes. Experimental results show that this method can obtain a good compression ratio as well as keeping satisfactory quality of compressed images.

  12. An discussion on Graphological Deviation in Oliver Twist

    Institute of Scientific and Technical Information of China (English)

    肖潇

    2016-01-01

    In stylistic analysis,when we identifying the stylistic features in literary works,deviation serves as an important sign.According to Leech,there are eight types of deviation in poetry:lexical deviation,grammatical deviation,phonological deviation,graphological deviation,semantic deviation,dialectal deviation,deviation of register,deviation of historical period. Realism marks as an significant development in the history of fiction,for its success in achieving an exposure of the truth of people’s real life and fierce social problems.And foregrounded feature is inevitable part that constitute his language style.We will focus on Oliver Twist,for it is presented with unique writing style,which worthy our investigation.

  13. Twisted Electromagnetic Modes and Sagnac Ring-Lasers

    CERN Document Server

    Burton, D A; Tucker, R W; Wiltshire, D L; Burton, David A.; Noble, Adam; Tucker, Robin W.; Wiltshire, David L.

    2005-01-01

    A new approximation scheme, designed to solve the covariant Maxwell equations inside a rotating hollow slender conducting cavity (modelling a ring-laser), is constructed. It is shown that for well-defined conditions there exist TE and TM modes with respect to the longitudinal axis of the cavity. A twisted mode spectrum is found to depend on the integrated Frenet torsion of the cavity and this in turn may affect the Sagnac beat frequency induced by a non-zero rotation of the cavity. The analysis is motivated by attempts to use ring-lasers to measure terrestrial gravito-magnetism or the Lense-Thirring effect produced by the rotation of the Earth.

  14. Influence of Endwall Contouring on the Secondary Flow in Turbine Nozzle Guide Vane

    Institute of Scientific and Technical Information of China (English)

    SUN Da-wei; QIAO Wei-yang; XU Kai-fu

    2009-01-01

    Numerical simulations are carried out to investigate the effect of the endwall contouring on the secondary flow in turbine nozzle guide vane. The three contoured cascades with the same contouring profile and the different positions where the contoured profile locates at are researched. The results show that the contouring configuration can reduce the aerodynamic losses of the cascade. The flat side takes advantage of a stronger decrease of the losses, compared to the contoured side. The contouring configuration can also inhibit the secondary flow. The contoured cascade in which the contouring profile starts upstream of the airfoil, ends at the middle of the airfoil has the best effect of improving secondary flow.

  15. Mutations in TWIST, a basic helix-loop-helix transcription factor, in Saethre-Chotzen syndrome.

    Science.gov (United States)

    Howard, T D; Paznekas, W A; Green, E D; Chiang, L C; Ma, N; Ortiz de Luna, R I; Garcia Delgado, C; Gonzalez-Ramos, M; Kline, A D; Jabs, E W

    1997-01-01

    Saethre-Chotzen syndrome is one of the most common autosomal dominant disorders of craniosynostosis in humans and is characterized by craniofacial and limb anomalies. The locus for Saethre-Chotzen syndrome maps to chromosome 7p21-p22. We have evaluated TWIST, a basic helix-loop-helix transcription factor, as a candidate gene for this condition because its expression pattern and mutant phenotypes in Drosophila and mouse are consistent with the Saethre-Chotzen phenotype. We mapped TWIST to human chromosome 7p21-p22 and mutational analysis reveals nonsense, missense, insertion and deletion mutations in patients. These mutations occur within the basic DNA binding, helix I and loop domains, or result in premature termination of the protein. Studies in Drosophila indicate that twist may affect the transcription of fibroblast growth factor receptors (FGFRs), another gene family implicated in human craniosynostosis. The emerging cascade of molecular components involved in craniofacial and limb development now includes TWIST, which may function as an upstream regulator of FGFRs.

  16. Correlation functions of twist fields from Ward identities in the massive Dirac theory

    Science.gov (United States)

    Doyon, Benjamin; Silk, James

    2011-07-01

    We derive non-linear differential equations for correlation functions of U(1) twist fields in the two-dimensional massive Dirac theory. Primary U(1) twist fields correspond to exponential fields in the sine-Gordon model at the free-fermion point, and it is well-known that their vacuum two-point functions are determined by integrable differential equations. We extend part of this result to more general quantum states (pure or mixed) and to certain descendents, showing that some two-point functions are determined by the sinh-Gordon differential equations whenever there is translation and parity invariance, and the density matrix is the exponential of a bilinear expression in fermions. We use methods involving Ward identities associated to the copy-rotation symmetry in a model with two independent, anti-commuting copies. Such methods were used in the context of the thermally perturbed Ising quantum field theory model. We show that they are applicable to the Dirac theory as well, and we suggest that they are likely to have a much wider applicability to free fermion models in general. Finally, we note that our form-factor study of descendents twist fields combined with a CFT analysis provides a new way of evaluating vacuum expectation values of primary U(1) twist fields: by deriving and solving a recursion relation.

  17. Correlation functions of twist fields from Ward identities in the massive Dirac theory

    Energy Technology Data Exchange (ETDEWEB)

    Doyon, Benjamin [Department of Mathematics, King' s College London, Strand WC2R 2LS (United Kingdom); Silk, James [Department of Mathematical Sciences, Durham University, Science Laboratories, South Road, Durham DH1 3LE (United Kingdom)

    2011-07-22

    We derive non-linear differential equations for correlation functions of U(1) twist fields in the two-dimensional massive Dirac theory. Primary U(1) twist fields correspond to exponential fields in the sine-Gordon model at the free-fermion point, and it is well-known that their vacuum two-point functions are determined by integrable differential equations. We extend part of this result to more general quantum states (pure or mixed) and to certain descendents, showing that some two-point functions are determined by the sinh-Gordon differential equations whenever there is translation and parity invariance, and the density matrix is the exponential of a bilinear expression in fermions. We use methods involving Ward identities associated to the copy-rotation symmetry in a model with two independent, anti-commuting copies. Such methods were used in the context of the thermally perturbed Ising quantum field theory model. We show that they are applicable to the Dirac theory as well, and we suggest that they are likely to have a much wider applicability to free fermion models in general. Finally, we note that our form-factor study of descendents twist fields combined with a CFT analysis provides a new way of evaluating vacuum expectation values of primary U(1) twist fields: by deriving and solving a recursion relation.

  18. Needleless electrospinning with twisted wire spinneret.

    Science.gov (United States)

    Holopainen, Jani; Penttinen, Toni; Santala, Eero; Ritala, Mikko

    2015-01-16

    A needleless electrospinning setup named 'Needleless Twisted Wire Electrospinning' was developed. The polymer solution is electrospun from the surface of a twisted wire set to a high voltage and collected on a cylindrical collector around the wire. Multiple Taylor cones are simultaneously self-formed on the downward flowing solution. The system is robust and simple with no moving parts aside from the syringe pump used to transport the solution to the top of the wire. The structure and process parameters of the setup and the results on the preparation of polyvinyl pyrrolidone (PVP), hydroxyapatite (HA) and bioglass fibers with the setup are presented. PVP fiber sheets with areas of 40 × 120 cm(2) and masses up to 1.15 g were prepared. High production rates of 5.23 g h(-1) and 1.40 g h(-1) were achieved for PVP and HA respectively. The major limiting factor of the setup is drying of the polymer solution on the wire during the electrospinning process which will eventually force to interrupt the process for cleaning of the wire. Possible solutions to this problem and other ways to develop the setup are discussed. The presented system provides a simple way to increase the production rate and area of fiber sheet as compared with the conventional needle electrospinning.

  19. Holographic generation of highly twisted electron beams

    CERN Document Server

    Grillo, Vincenzo; Mafakheri, Erfan; Frabboni, Stefano; Karimi, Ebrahim; Boyd, Robert W

    2014-01-01

    Free electrons can possess an intrinsic orbital angular momentum, similar to those in an electron cloud, upon free-space propagation. The wavefront corresponding to the electron's wavefunction forms a helical structure with a number of twists given by the \\emph{angular speed}. Beams with a high number of twists are of particular interest because they carry a high magnetic moment about the propagation axis. Among several different techniques, electron holography seems to be a promising approach to shape a \\emph{conventional} electron beam into a helical form with large values of angular momentum. Here, we propose and manufacture a nano-fabricated phase hologram for generating a beam of this kind with an orbital angular momentum up to 200$\\hbar$. Based on a novel technique the value of orbital angular momentum of the generated beam are measured, then compared with simulations. Our work, apart from the technological achievements, may lead to a way of generating electron beams with a high quanta of magnetic momen...

  20. Twisting the [ital N]=2 string

    Energy Technology Data Exchange (ETDEWEB)

    Ketov, S.V.; Lechtenfeld, O. (Institut fuer Theoretische Physik, Universitaet Hannover, Appelstrasse 2, 30167 Hannover (Germany)); Parkes, A.J. (Department of Artificial Intelligence, 80 South Bridge, Edinburgh EH1 9HN (United Kingdom))

    1995-03-15

    The most general homogeneous monodromy conditions in [ital N]=2 string theory are classified in terms of the conjugacy classes of the global symmetry group U(1,1)[direct product][ital openZ][sub 2]. For classes which generate a discrete subgroup [Gamma], the corresponding target space backgrounds [ital openC][sup 1,1]/[Gamma] include half spaces, complex orbifolds, and tori. We propose a generalization of the intercept formula to matrix-valued twists, but find massless physical states only for [Gamma]=[ital open]1 (untwisted) and [Gamma]=[ital openZ][sub 2] (in the manner of Mathur and Mukhi), as well as for [Gamma] being a parabolic element of U(1,1). In particular, the 16 [ital openZ][sub 2]-twisted sectors of the [ital N]=2 string are investigated, and the corresponding ground states are identified via bosonization and BRST cohomology. We find enough room for an extended multiplet of spacetime'' supersymmetry, with the number of supersymmetries being dependent on global spacetime'' topology. However, world-sheet locality for the chiral vertex operators does not permit interactions among all massless spacetime'' fermions.

  1. Twisting Fluorescence through Extrinsic Chiral Antennas.

    Science.gov (United States)

    Yan, Chen; Wang, Xiaolong; Raziman, T V; Martin, Olivier J F

    2017-03-22

    Plasmonic antennas and planar structures have been undergoing intensive developments in order to control the scattering and absorption of light. One specific class, extrinsic chiral surfaces, that does not possess 2-fold rotational symmetry exhibits strong asymmetric transmission for different circular polarizations under obliquely incident illumination. In this work, we show that the design of those surfaces can be optimized with complex multipolar resonances in order to twist the fluorescence emission from nearby molecules. While this emission is usually dipolar and linearly polarized, the interaction with these resonances twists it into a multipolar radiation pattern with opposite helicity in different directions. The proposed structure maximizes this effect and provides control over the polarization of light. Splitting of left- and right-handed circularly polarized light is experimentally obtained in the backward direction. These results highlight the intricate interplay between the near-field absorption and the far-field scattering of a plasmonic nanostructure and are further used for modifying the emission of incoherent quantum sources. Our finding can potentially lead to the development of polarization- and angle-resolved ultracompact optical devices.

  2. Twisted Alexander polynomials of hyperbolic knots

    CERN Document Server

    Dunfield, Nathan M; Jackson, Nicholas

    2011-01-01

    We study a twisted Alexander polynomial naturally associated to a hyperbolic knot in an integer homology 3-sphere via a lift of the holonomy representation to SL(2, C). It is an unambiguous symmetric Laurent polynomial whose coefficients lie in the trace field of the knot. It contains information about genus, fibering, and chirality, and moreover is powerful enough to sometimes detect mutation. We calculated this invariant numerically for all 313,209 hyperbolic knots in S^3 with at most 15 crossings, and found that in all cases it gave a sharp bound on the genus of the knot and determined both fibering and chirality. We also study how such twisted Alexander polynomials vary as one moves around in an irreducible component X_0 of the SL(2, C)-character variety of the knot group. We show how to understand all of these polynomials at once in terms of a polynomial whose coefficients lie in the function field of X_0. We use this to help explain some of the patterns observed for knots in S^3, and explore a potential...

  3. Twisted geometries, twistors and conformal transformations

    CERN Document Server

    Långvik, Miklos

    2016-01-01

    The twisted geometries of spin network states are described by simple twistors, isomorphic to null twistors with a time-like direction singled out. The isomorphism depends on the Immirzi parameter, and reduces to the identity when the parameter goes to infinity. Using this twistorial representation we study the action of the conformal group SU(2,2) on the classical phase space of loop quantum gravity, described by twisted geometry. The generators of translations and conformal boosts do not preserve the geometric structure, whereas the dilatation generator does. It corresponds to a 1-parameter family of embeddings of T*SL(2,C) in twistor space, and its action preserves the intrinsic geometry while changing the extrinsic one - that is the boosts among polyhedra. We discuss the implication of this action from a dynamical point of view, and compare it with a discretisation of the dilatation generator of the continuum phase space, given by the Lie derivative of the group character. At leading order in the continuu...

  4. How the embryonic brain tube twists

    Science.gov (United States)

    Chen, Zi; Guo, Qiaohang; Forsch, Nickolas; Taber, Larry

    2014-03-01

    During early development, the tubular brain of the chick embryo undergoes a combination of progressive ventral bending and rightward torsion. This deformation is one of the major organ-level symmetry-breaking events in development. Available evidence suggests that bending is caused by differential growth, but the mechanism for torsion remains poorly understood. Since the heart almost always loops in the same direction that the brain twists, researchers have speculated that heart looping affects the direction of brain torsion. However, direct evidence is virtually nonexistent, nor is the mechanical origin of such torsion understood. In our study, experimental perturbations show that the bending and torsional deformations in the brain are coupled and that the vitelline membrane applies an external load necessary for torsion to occur. In addition, the asymmetry of the looping heart gives rise to the chirality of the twisted brain. A computational model is used to interpret these findings. Our work clarifies the mechanical origins of brain torsion and the associated left-right asymmetry, reminiscent of D'Arcy Thompson's view of biological form as ``diagram of forces''.

  5. Structure of twisted and buckled bilayer graphene

    Science.gov (United States)

    Jain, Sandeep K.; Juričić, Vladimir; Barkema, Gerard T.

    2017-03-01

    We study the atomic structure of twisted bilayer graphene, with very small mismatch angles (θ ∼ {0.28}0), a topic of intense recent interest. We use simulations, in which we combine a recently presented semi-empirical potential for single-layer graphene, with a new term for out-of-plane deformations, (Jain et al 2015 J. Phys. Chem. C 119 9646) and an often-used interlayer potential (Kolmogorov et al 2005 Phys. Rev. B 71 235415). This combination of potentials is computationally cheap but accurate and precise at the same time, allowing us to study very large samples, which is necessary to reach very small mismatch angles in periodic samples. By performing large scale atomistic simulations, we show that the vortices appearing in the Moiré pattern in the twisted bilayer graphene samples converge to a constant size in the thermodynamic limit. Furthermore, the well known sinusoidal behavior of energy no longer persists once the misorientation angle becomes very small (θ \\lt {1}0). We also show that there is a significant buckling after the relaxation in the samples, with the buckling height proportional to the system size. These structural properties have direct consequences on the electronic and optical properties of bilayer graphene.

  6. Contour polygonal approximation using shortest path in networks

    CERN Document Server

    Backes, André Ricardo; Bruno, Odemir Martinez

    2013-01-01

    Contour polygonal approximation is a simplified representation of a contour by line segments, so that the main characteristics of the contour remain in a small number of line segments. This paper presents a novel method for polygonal approximation based on the Complex Networks theory. We convert each point of the contour into a vertex, so that we model a regular network. Then we transform this network into a Small-World Complex Network by applying some transformations over its edges. By analyzing of network properties, especially the geodesic path, we compute the polygonal approximation. The paper presents the main characteristics of the method, as well as its functionality. We evaluate the proposed method using benchmark contours, and compare its results with other polygonal approximation methods.

  7. Contour-Based Surface Reconstruction using MPU Implicit Models.

    Science.gov (United States)

    Braude, Ilya; Marker, Jeffrey; Museth, Ken; Nissanov, Jonathan; Breen, David

    2007-03-01

    This paper presents a technique for creating a smooth, closed surface from a set of 2D contours, which have been extracted from a 3D scan. The technique interprets the pixels that make up the contours as points in ℝ(3) and employs Multi-level Partition of Unity (MPU) implicit models to create a surface that approximately fits to the 3D points. Since MPU implicit models additionally require surface normal information at each point, an algorithm that estimates normals from the contour data is also described. Contour data frequently contains noise from the scanning and delineation process. MPU implicit models provide a superior approach to the problem of contour-based surface reconstruction, especially in the presence of noise, because they are based on adaptive implicit functions that locally approximate the points within a controllable error bound. We demonstrate the effectiveness of our technique with a number of example datasets, providing images and error statistics generated from our results.

  8. Contour integration and segmentation with a new lateral connections model

    Science.gov (United States)

    Cai, Chao

    2011-11-01

    Automatically target contour detection from cluttered scenes is a very difficult task for computer vision. Humans, however, have a much better background suppress ability. The preceding models could not implement such a task very well. In this letter, an effective contour integration method based on human visual perception mechanism is proposed. The algorithm combines the properties of primary visual cortex and psychology researching results to simulate the contour perception of the V1 cortex. The new lateral connection based computational model have a better texture suppress ability, while, target's contour is enhanced. Compared with traditional methods, experiments show that the new method implement a more reasonable simulation of the V1 function structure, availably enhance the target's contour while suppress the cluttered background, obtain a balance between over and lose detection, besides, it has better accuracy with less computational complexity and time-consuming.

  9. Synthesis of Polysyllabic Sequences of Thai Tones Using a Generative Model of Fundamental Frequency Contours

    Science.gov (United States)

    Seresangtakul, Pusadee; Takara, Tomio

    In this paper, the distinctive tones of Thai in running speech are studied. We present rules to synthesize F0 contours of Thai tones in running speech by using the generative model of F0 contours. Along with our method, the pitch contours of Thai polysyllabic words, both disyllabic and trisyllabic words, were analyzed. The coarticulation effect of Thai tones in running speech were found. Based on the analysis of the polysyllabic words using this model, rules are derived and applied to synthesize Thai polysyllabic tone sequences. We performed listening tests to evaluate intelligibility of the rules for Thai tones generation. The average intelligibility scores became 98.8%, and 96.6% for disyllabic and trisyllabic words, respectively. From these result, the rule of the tones' generation was shown to be effective. Furthermore, we constructed the connecting rules to synthesize suprasegmental F0 contours using the trisyllable training rules' parameters. The parameters of the first, the third, and the second syllables were selected and assigned to the initial, the ending, and the remaining syllables in a sentence, respectively. Even such a simple rule, the synthesized phrases/senetences were completely identified in listening tests. The MOSs (Mean Opinion Score) was 3.50 while the original and analysis/synthesis samples were 4.82 and 3.59, respectively.

  10. Cellularity of diagram algebras as twisted semigroup algebras

    CERN Document Server

    Wilcox, Stewart

    2010-01-01

    The Temperley-Lieb and Brauer algebras and their cyclotomic analogues, as well as the partition algebra, are all examples of twisted semigroup algebras. We prove a general theorem about the cellularity of twisted semigroup algebras of regular semigroups. This theorem, which generalises a recent result of East about semigroup algebras of inverse semigroups, allows us to easily reproduce the cellularity of these algebras.

  11. Behaviour at infinity of solutions of twisted convolution equations

    Energy Technology Data Exchange (ETDEWEB)

    Volchkov, Valerii V; Volchkov, Vitaly V [Donetsk National University, Donetsk (Ukraine)

    2012-02-28

    We obtain a precise characterization of the minimal rate of growth at infinity of non-trivial solutions of twisted convolution equations in unbounded domains of C{sup n}. As an application, we obtain definitive versions of the two-radii theorem for twisted spherical means.

  12. On the commutator length of a Dehn twist

    CERN Document Server

    Szepietowski, Blazej

    2010-01-01

    We show that on a nonorientable surface of genus at least 7 any power of a Dehn twist is equal to a single commutator in the mapping class group and the same is true, under additional assumptions, for the twist subgroup, and also for the extended mapping class group of an orientable surface of genus at least 3.

  13. Quadratic Twists of Rigid Calabi–Yau Threefolds Over

    DEFF Research Database (Denmark)

    Gouvêa, Fernando Q.; Kiming, Ian; Yui, Noriko

    2013-01-01

    We consider rigid Calabi–Yau threefolds defined over Q and the question of whether they admit quadratic twists. We give a precise geometric definition of the notion of a quadratic twists in this setting. Every rigid Calabi–Yau threefold over Q is modular so there is attached to it a certain newfo...

  14. Design optimization of a twist compliant mechanism with nonlinear stiffness

    Science.gov (United States)

    Tummala, Y.; Frecker, M. I.; Wissa, A. A.; Hubbard, J. E., Jr.

    2014-10-01

    A contact-aided compliant mechanism called a twist compliant mechanism (TCM) is presented in this paper. This mechanism has nonlinear stiffness when it is twisted in both directions along its axis. The inner core of the mechanism is primarily responsible for its flexibility in one twisting direction. The contact surfaces of the cross-members and compliant sectors are primarily responsible for its high stiffness in the opposite direction. A desired twist angle in a given direction can be achieved by tailoring the stiffness of a TCM. The stiffness of a compliant twist mechanism can be tailored by varying thickness of its cross-members, thickness of the core and thickness of its sectors. A multi-objective optimization problem with three objective functions is proposed in this paper, and used to design an optimal TCM with desired twist angle. The objective functions are to minimize the mass and maximum von-Mises stress observed, while minimizing or maximizing the twist angles under specific loading conditions. The multi-objective optimization problem proposed in this paper is solved for an ornithopter flight research platform as a case study, with the goal of using the TCM to achieve passive twisting of the wing during upstroke, while keeping the wing fully extended and rigid during the downstroke. Prototype TCMs have been fabricated using 3D printing and tested. Testing results are also presented in this paper.

  15. Twisted tubular photobioreactor fluid dynamics evaluation for energy consumption minimization

    NARCIS (Netherlands)

    Gómez-Pérez, C.A.; Espinosa Oviedo, J.J.; Montenegro Ruiz, L.C.; Boxtel, van A.J.B.

    2017-01-01

    This paper discusses a new tubular PhotoBioReactor (PBR) called twisted tubular PBR. The geometry of a twisted tubular PBR induces swirl mixing to guarantee good exposure of microalgae to Light-Dark (LD) cycles and to the nutrients and dissolved CO 2 . The paper analyses the energy uptake for fluid

  16. Twisted Fock representations of noncommutative Kähler manifolds

    Science.gov (United States)

    Sako, Akifumi; Umetsu, Hiroshi

    2016-09-01

    We introduce twisted Fock representations of noncommutative Kähler manifolds and give their explicit expressions. The twisted Fock representation is a representation of the Heisenberg like algebra whose states are constructed by applying creation operators to a vacuum state. "Twisted" means that creation operators are not Hermitian conjugate of annihilation operators in this representation. In deformation quantization of Kähler manifolds with separation of variables formulated by Karabegov, local complex coordinates and partial derivatives of the Kähler potential with respect to coordinates satisfy the commutation relations between the creation and annihilation operators. Based on these relations, we construct the twisted Fock representation of noncommutative Kähler manifolds and give a dictionary to translate between the twisted Fock representations and functions on noncommutative Kähler manifolds concretely.

  17. Landau damping of Langmuir twisted waves with kappa distributed electrons

    Energy Technology Data Exchange (ETDEWEB)

    Arshad, Kashif, E-mail: kashif.arshad.butt@gmail.com; Aman-ur-Rehman [Pakistan Institute of Engineering and Applied Sciences, P. O. Nilore, Islamabad 45650 (Pakistan); Mahmood, Shahzad [Pakistan Institute of Engineering and Applied Sciences, P. O. Nilore, Islamabad 45650 (Pakistan); Theoretical Physics Division, PINSTECH, P.O. Nilore, Islamabad 44000 (Pakistan)

    2015-11-15

    The kinetic theory of Landau damping of Langmuir twisted modes is investigated in the presence of orbital angular momentum of the helical (twisted) electric field in plasmas with kappa distributed electrons. The perturbed distribution function and helical electric field are considered to be decomposed by Laguerre-Gaussian mode function defined in cylindrical geometry. The Vlasov-Poisson equation is obtained and solved analytically to obtain the weak damping rates of the Langmuir twisted waves in a nonthermal plasma. The strong damping effects of the Langmuir twisted waves at wavelengths approaching Debye length are also obtained by using an exact numerical method and are illustrated graphically. The damping rates of the planar Langmuir waves are found to be larger than the twisted Langmuir waves in plasmas which shows opposite behavior as depicted in Fig. 3 by J. T. Mendoça [Phys. Plasmas 19, 112113 (2012)].

  18. Twisted Fock Representations of Noncommutative K\\"ahler Manifolds

    CERN Document Server

    Sako, Akifumi

    2016-01-01

    We introduce twisted Fock representations of noncommutative K\\"ahler manifolds and give their explicit expressions. The twisted Fock representation is a representation of the Heisenberg like algebra whose states are constructed by acting creation operators on a vacuum state. "Twisted" means that creation operators are not hermitian conjugate of annihilation operators in this representation. In deformation quantization of K\\"ahler manifolds with separation of variables formulated by Karabegov, local complex coordinates and partial derivatives of the K\\"ahler potential with respect to coordinates satisfy the commutation relations between the creation and annihilation operators. Based on these relations, we construct the twisted Fock representation of noncommutative K\\"ahler manifolds and give a dictionary to translate between the twisted Fock representations and functions on noncommutative K\\"ahler manifolds concretely.

  19. Twist1 activity thresholds define multiple functions in limb development.

    Science.gov (United States)

    Krawchuk, Dayana; Weiner, Shoshana J; Chen, You-Tzung; Lu, Benson C; Costantini, Frank; Behringer, Richard R; Laufer, Ed

    2010-11-01

    The basic helix-loop-helix transcription factor Twist1 is essential for normal limb development. Twist1(-/-) embryos die at midgestation. However, studies on early limb buds found that Twist1(-/-) mutant limb mesenchyme has an impaired response to FGF signaling from the apical ectodermal ridge, which disrupts the feedback loop between the mesenchyme and AER, and reduces and shifts anteriorly Shh expression in the zone of polarizing activity. We have combined Twist1 null, hypomorph and conditional alleles to generate a Twist1 allelic series that survives to birth. As Twist1 activity is reduced, limb skeletal defects progress from preaxial polydactyly to girdle reduction combined with hypoplasia, aplasia or mirror symmetry of all limb segments. With reduced Twist1 activity there is striking and progressive upregulation of ectopic Shh expression in the anterior of the limb, combined with an anterior shift in the posterior Shh domain, which is expressed at normal intensity, and loss of the posterior AER. Consequently limb outgrowth is initially impaired, before an ectopic anterior Shh domain expands the AER, promoting additional growth and repatterning. Reducing the dosage of FGF targets of the Etv gene family, which are known repressors of Shh expression in anterior limb mesenchyme, strongly enhances the anterior skeletal phenotype. Conversely this and other phenotypes are suppressed by reducing the dosage of the Twist1 antagonist Hand2. Our data support a model whereby multiple Twist1 activity thresholds contribute to early limb bud patterning, and suggest how particular combinations of skeletal defects result from differing amounts of Twist1 activity.

  20. Directed random polymers via nested contour integrals

    Science.gov (United States)

    Borodin, Alexei; Bufetov, Alexey; Corwin, Ivan

    2016-05-01

    We study the partition function of two versions of the continuum directed polymer in 1 + 1 dimension. In the full-space version, the polymer starts at the origin and is free to move transversally in R, and in the half-space version, the polymer starts at the origin but is reflected at the origin and stays in R-. The partition functions solve the stochastic heat equation in full-space or half-space with mixed boundary condition at the origin; or equivalently the free energy satisfies the Kardar-Parisi-Zhang equation. We derive exact formulas for the Laplace transforms of the partition functions. In the full-space this is expressed as a Fredholm determinant while in the half-space this is expressed as a Fredholm Pfaffian. Taking long-time asymptotics we show that the limiting free energy fluctuations scale with exponent 1 / 3 and are given by the GUE and GSE Tracy-Widom distributions. These formulas come from summing divergent moment generating functions, hence are not mathematically justified. The primary purpose of this work is to present a mathematical perspective on the polymer replica method which is used to derive these results. In contrast to other replica method work, we do not appeal directly to the Bethe ansatz for the Lieb-Liniger model but rather utilize nested contour integral formulas for moments as well as their residue expansions.

  1. Development of a Standardized Method for Contouring the Lumbosacral Plexus: A Preliminary Dosimetric Analysis of this Organ at Risk Among 15 Patients Treated With Intensity-Modulated Radiotherapy for Lower Gastrointestinal Cancers and the Incidence of Radiation-Induced Lumbosacral Plexopathy

    Energy Technology Data Exchange (ETDEWEB)

    Yi, Sun K., E-mail: sun.yi@ucdmc.ucdavis.edu [Department of Radiation Oncology, University of California, Davis Cancer Center, Sacramento, CA (United States); Mak, Walter [Department of Radiology, University of California, Davis Medical Center, Sacramento, CA (United States); Yang, Claus C.; Liu Tianxiao [Department of Radiation Oncology, University of Mississippi Medical Center, Jackson, MS (United States); Cui Jing; Chen, Allen M.; Purdy, James A.; Monjazeb, Arta M. [Department of Radiation Oncology, University of California, Davis Cancer Center, Sacramento, CA (United States); Do, Ly [Cancer Care Institute, San Jose, CA (United States)

    2012-10-01

    Purpose: To generate a reproducible step-wise guideline for the delineation of the lumbosacral plexus (LSP) on axial computed tomography (CT) planning images and to provide a preliminary dosimetric analysis on 15 representative patients with rectal or anal cancers treated with an intensity-modulated radiotherapy (IMRT) technique. Methods and Materials: A standardized method for contouring the LSP on axial CT images was devised. The LSP was referenced to identifiable anatomic structures from the L4-5 interspace to the level of the sciatic nerve. It was then contoured retrospectively on 15 patients treated with IMRT for rectal or anal cancer. No dose limitations were placed on this organ at risk during initial treatment planning. Dosimetric parameters were evaluated. The incidence of radiation-induced lumbosacral plexopathy (RILSP) was calculated. Results: Total prescribed dose to 95% of the planned target volume ranged from 50.4 to 59.4 Gy (median 54 Gy). The mean ({+-}standard deviation [SD]) LSP volume for the 15 patients was 100 {+-} 22 cm{sup 3} (range, 71-138 cm{sup 3}). The mean maximal dose to the LSP was 52.6 {+-} 3.9 Gy (range, 44.5-58.6 Gy). The mean irradiated volumes of the LSP were V40Gy = 58% {+-} 19%, V50Gy = 22% {+-} 23%, and V55Gy = 0.5% {+-} 0.9%. One patient (7%) was found to have developed RILSP at 13 months after treatment. Conclusions: The true incidence of RILSP in the literature is likely underreported and is not a toxicity commonly assessed by radiation oncologists. In our analysis the LSP commonly received doses approaching the prescribed target dose, and 1 patient developed RILSP. Identification of the LSP during IMRT planning may reduce RILSP. We have provided a reproducible method for delineation of the LSP on CT images and a preliminary dosimetric analysis for potential future dose constraints.

  2. Automated contouring error detection based on supervised geometric attribute distribution models for radiation therapy: A general strategy

    Energy Technology Data Exchange (ETDEWEB)

    Chen, Hsin-Chen; Tan, Jun; Dolly, Steven; Kavanaugh, James; Harold Li, H.; Altman, Michael; Gay, Hiram; Thorstad, Wade L.; Mutic, Sasa; Li, Hua, E-mail: huli@radonc.wustl.edu [Department of Radiation Oncology, Washington University, St. Louis, Missouri 63110 (United States); Anastasio, Mark A. [Department of Biomedical Engineering, Washington University, St. Louis, Missouri 63110 (United States); Low, Daniel A. [Department of Radiation Oncology, University of California Los Angeles, Los Angeles, California 90095 (United States)

    2015-02-15

    Purpose: One of the most critical steps in radiation therapy treatment is accurate tumor and critical organ-at-risk (OAR) contouring. Both manual and automated contouring processes are prone to errors and to a large degree of inter- and intraobserver variability. These are often due to the limitations of imaging techniques in visualizing human anatomy as well as to inherent anatomical variability among individuals. Physicians/physicists have to reverify all the radiation therapy contours of every patient before using them for treatment planning, which is tedious, laborious, and still not an error-free process. In this study, the authors developed a general strategy based on novel geometric attribute distribution (GAD) models to automatically detect radiation therapy OAR contouring errors and facilitate the current clinical workflow. Methods: Considering the radiation therapy structures’ geometric attributes (centroid, volume, and shape), the spatial relationship of neighboring structures, as well as anatomical similarity of individual contours among patients, the authors established GAD models to characterize the interstructural centroid and volume variations, and the intrastructural shape variations of each individual structure. The GAD models are scalable and deformable, and constrained by their respective principal attribute variations calculated from training sets with verified OAR contours. A new iterative weighted GAD model-fitting algorithm was developed for contouring error detection. Receiver operating characteristic (ROC) analysis was employed in a unique way to optimize the model parameters to satisfy clinical requirements. A total of forty-four head-and-neck patient cases, each of which includes nine critical OAR contours, were utilized to demonstrate the proposed strategy. Twenty-nine out of these forty-four patient cases were utilized to train the inter- and intrastructural GAD models. These training data and the remaining fifteen testing data sets

  3. Time-varying wing-twist improves aerodynamic efficiency of forward flight in butterflies.

    Directory of Open Access Journals (Sweden)

    Lingxiao Zheng

    Full Text Available Insect wings can undergo significant chordwise (camber as well as spanwise (twist deformation during flapping flight but the effect of these deformations is not well understood. The shape and size of butterfly wings leads to particularly large wing deformations, making them an ideal test case for investigation of these effects. Here we use computational models derived from experiments on free-flying butterflies to understand the effect of time-varying twist and camber on the aerodynamic performance of these insects. High-speed videogrammetry is used to capture the wing kinematics, including deformation, of a Painted Lady butterfly (Vanessa cardui in untethered, forward flight. These experimental results are then analyzed computationally using a high-fidelity, three-dimensional, unsteady Navier-Stokes flow solver. For comparison to this case, a set of non-deforming, flat-plate wing (FPW models of wing motion are synthesized and subjected to the same analysis along with a wing model that matches the time-varying wing-twist observed for the butterfly, but has no deformation in camber. The simulations show that the observed butterfly wing (OBW outperforms all the flat-plate wings in terms of usable force production as well as the ratio of lift to power by at least 29% and 46%, respectively. This increase in efficiency of lift production is at least three-fold greater than reported for other insects. Interestingly, we also find that the twist-only-wing (TOW model recovers much of the performance of the OBW, demonstrating that wing-twist, and not camber is key to forward flight in these insects. The implications of this on the design of flapping wing micro-aerial vehicles are discussed.

  4. The force-free twisted magnetosphere of a neutron star

    Science.gov (United States)

    Akgün, T.; Miralles, J. A.; Pons, J. A.; Cerdá-Durán, P.

    2016-10-01

    We present a detailed analysis of the properties of twisted, force-free magnetospheres of non-rotating neutron stars, which are of interest in the modelling of magnetar properties and evolution. In our models the magnetic field smoothly matches to a current-free (vacuum) solution at some large external radius, and they are specifically built to avoid pathological surface currents at any of the interfaces. By exploring a large range of parameters, we find a few remarkable general trends. We find that the total dipolar moment can be increased by up to 40 per cent with respect to a vacuum model with the same surface magnetic field, due to the contribution of magnetospheric currents to the global magnetic field. Thus, estimates of the surface magnetic field based on the large-scale dipolar braking torque are slightly overestimating the surface value by the same amount. Consistently, there is a moderate increase in the total energy of the model with respect to the vacuum solution of up to 25 per cent, which would be the available energy budget in the event of a fast, global magnetospheric reorganization commonly associated with magnetar flares. We have also found the interesting result of the existence of a critical twist (ϕmax ≲ 1.5 rad), beyond which we cannot find any more numerical solutions. Combining the models considered in this paper with the evolution of the interior of neutron stars will allow us to study the influence of the magnetosphere on the long-term magnetic, thermal, and rotational evolution.

  5. Segmentation and Tracking of Lymphocytes Based on Modified Active Contour Models in Phase Contrast Microscopy Images

    Directory of Open Access Journals (Sweden)

    Yali Huang

    2015-01-01

    Full Text Available The paper proposes an improved active contour model for segmenting and tracking accurate boundaries of the single lymphocyte in phase-contrast microscopic images. Active contour models have been widely used in object segmentation and tracking. However, current external-force-inspired methods are weak at handling low-contrast edges and suffer from initialization sensitivity. In order to segment low-contrast boundaries, we combine the region information of the object, extracted by morphology gray-scale reconstruction, and the edge information, extracted by the Laplacian of Gaussian filter, to obtain an improved feature map to compute the external force field for the evolution of active contours. To alleviate initial location sensitivity, we set the initial contour close to the real boundaries by performing morphological image processing. The proposed method was tested on live lymphocyte images acquired through the phase-contrast microscope from the blood samples of mice, and comparative experimental results showed the advantages of the proposed method in terms of the accuracy and the speed. Tracking experiments showed that the proposed method can accurately segment and track lymphocyte boundaries in microscopic images over time even in the presence of low-contrast edges, which will provide a good prerequisite for the quantitative analysis of lymphocyte morphology and motility.

  6. Automatic Segmentation of Nature Object Using Salient Edge Points Based Active Contour

    Directory of Open Access Journals (Sweden)

    Shangbing Gao

    2015-01-01

    Full Text Available Natural image segmentation is often a crucial first step for high-level image understanding, significantly reducing the complexity of content analysis of images. LRAC may have some disadvantages. (1 Segmentation results heavily depend on the initial contour selection which is a very skillful task. (2 In some situations, manual interactions are infeasible. To overcome these shortcomings, we propose a novel model for unsupervised segmentation of viewer’s attention object from natural images based on localizing region-based active model (LRAC. With aid of the color boosting Harris detector and the core saliency map, we get the salient object edge points. Then, these points are employed as the seeds of initial convex hull. Finally, this convex hull is improved by the edge-preserving filter to generate the initial contour for our automatic object segmentation system. In contrast with localizing region-based active contours that require considerable user interaction, the proposed method does not require it; that is, the segmentation task is fulfilled in a fully automatic manner. Extensive experiments results on a large variety of natural images demonstrate that our algorithm consistently outperforms the popular existing salient object segmentation methods, yielding higher precision and better recall rates. Our framework can reliably and automatically extract the object contour from the complex background.

  7. The prevalence of body contouring surgery after gastric bypass surgery.

    Science.gov (United States)

    Kitzinger, Hugo B; Abayev, Sara; Pittermann, Anna; Karle, Birgit; Kubiena, Harald; Bohdjalian, Arthur; Langer, Felix B; Prager, Gerhard; Frey, Manfred

    2012-01-01

    As bariatric surgery has become more popular, more patients are undergoing body contouring surgery after massive weight loss. Many of the surgical procedures performed on the massive weight loss patient are complex and labor-intensive. Therefore, the plastic surgery unit needs to be prepared for a patient's demand. Little literature is available on how frequently patients who have undergone gastric bypass surgery receive body contouring surgery. Two hundred fifty-two subjects (out of 425 who were mailed the questionnaire) who had undergone gastric bypass surgery between 2003 and 2009 completed the questionnaire, which obtained information on body image satisfaction and frequency of body contouring surgery after massive weight loss. Of all patients, 74% desire a body contouring surgery after gastric bypass surgery. Fifty-three patients (21%) have undergone a total of 61 body contouring procedures. The most common were abdominoplasties (59%), followed by lower body lifts (20%). In contrast to a positive judgment of the general aspect of the body image satisfaction after massive weight loss, both genders are unsatisfied with body areas like abdomen/waist, breast, and thighs. Paralleling the increasing use of bariatric surgery, there is a high demand for body contouring surgery. A huge disparity exists between the number of subjects who desire a body contouring surgery and those who actually received it.

  8. GPU based contouring method on grid DEM data

    Science.gov (United States)

    Tan, Liheng; Wan, Gang; Li, Feng; Chen, Xiaohui; Du, Wenlong

    2017-08-01

    This paper presents a novel method to generate contour lines from grid DEM data based on the programmable GPU pipeline. The previous contouring approaches often use CPU to construct a finite element mesh from the raw DEM data, and then extract contour segments from the elements. They also need a tracing or sorting strategy to generate the final continuous contours. These approaches can be heavily CPU-costing and time-consuming. Meanwhile the generated contours would be unsmooth if the raw data is sparsely distributed. Unlike the CPU approaches, we employ the GPU's vertex shader to generate a triangular mesh with arbitrary user-defined density, in which the height of each vertex is calculated through a third-order Cardinal spline function. Then in the same frame, segments are extracted from the triangles by the geometry shader, and translated to the CPU-side with an internal order in the GPU's transform feedback stage. Finally we propose a ;Grid Sorting; algorithm to achieve the continuous contour lines by travelling the segments only once. Our method makes use of multiple stages of GPU pipeline for computation, which can generate smooth contour lines, and is significantly faster than the previous CPU approaches. The algorithm can be easily implemented with OpenGL 3.3 API or higher on consumer-level PCs.

  9. Optical Twist Induced by Plasmonic Resonance

    Science.gov (United States)

    Chen, Jun; Wang, Neng; Cui, Liyong; Li, Xiao; Lin, Zhifang; Ng, Jack

    2016-06-01

    Harvesting light for optical torque is of significant importance, owing to its ability to rotate nano- or micro-objects. Nevertheless, applying a strong optical torque remains a challenging task: angular momentum must conserve but light is limited. A simple argument shows the tendency for two objects with strong mutual scattering or light exchange to exhibit a conspicuously enhanced optical torque without large extinction or absorption cross section. The torque on each object is almost equal but opposite, which we called optical twist. The effect is quite significant for plasmonic particle cluster, but can also be observed in structures with other morphologies. Such approach exhibits an unprecedentedly large torque to light extinction or absorption ratio, enabling limited light to exert a relatively large torque without severe heating. Our work contributes to the understanding of optical torque and introduces a novel way to manipulate the internal degrees of freedom of a structured particle cluster.

  10. Twisted Light Transmission over 143 kilometers

    CERN Document Server

    Krenn, Mario; Fink, Matthias; Fickler, Robert; Ursin, Rupert; Malik, Mehul; Zeilinger, Anton

    2016-01-01

    Spatial modes of light can potentially carry a vast amount of information, making them promising candidates for both classical and quantum communication. However, the distribution of such modes over large distances remains difficult. Intermodal coupling complicates their use with common fibers, while free-space transmission is thought to be strongly influenced by atmospheric turbulence. Here we show the transmission of orbital angular momentum modes of light over a distance of 143 kilometers between two Canary Islands, which is 50 times greater than the maximum distance achieved previously. As a demonstration of the transmission quality, we use superpositions of these modes to encode a short message. At the receiver, an artificial neural network is used for distinguishing between the different twisted light superpositions. The algorithm is able to identify different mode superpositions with an accuracy of more than 80% up to the third mode order, and decode the transmitted message with an error rate of 8.33%....

  11. Twisted Polynomials and Forgery Attacks on GCM

    DEFF Research Database (Denmark)

    Abdelraheem, Mohamed Ahmed A. M. A.; Beelen, Peter; Bogdanov, Andrey;

    2015-01-01

    nonce misuse resistance, such as POET. The algebraic structure of polynomial hashing has given rise to security concerns: At CRYPTO 2008, Handschuh and Preneel describe key recovery attacks, and at FSE 2013, Procter and Cid provide a comprehensive framework for forgery attacks. Both approaches rely...... heavily on the ability to construct forgery polynomials having disjoint sets of roots, with many roots (“weak keys”) each. Constructing such polynomials beyond naïve approaches is crucial for these attacks, but still an open problem. In this paper, we comprehensively address this issue. We propose to use...... in an improved key recovery algorithm. As cryptanalytic applications of our twisted polynomials, we develop the first universal forgery attacks on GCM in the weak-key model that do not require nonce reuse. Moreover, we present universal weak-key forgeries for the nonce-misuse resistant AE scheme POET, which...

  12. Regular non-twisting S-branes

    CERN Document Server

    Obregón, O; Ryan, M P; Obregon, Octavio; Quevedo, Hernando; Ryan, Michael P.

    2004-01-01

    We construct a family of time and angular dependent, regular S-brane solutions which corresponds to a simple analytical continuation of the Zipoy-Voorhees 4-dimensional vacuum spacetime. The solutions are asymptotically flat and turn out to be free of singularities without requiring a twist in space. They can be considered as the simplest non-singular generalization of the singular S0-brane solution. We analyze the properties of a representative of this family of solutions and show that it resembles to some extent the asymptotic properties of the regular Kerr S-brane. The R-symmetry corresponds, however, to the general Lorentzian symmetry. Several generalizations of this regular solution are derived which include a charged S-brane and an additional dilatonic field.

  13. A Solvable Twisted One-Plaquette Model

    Science.gov (United States)

    Billó, M.; D'Adda, A.

    We solve a hot twisted Eguchi-Kawai model with only timelike plaquettes in the deconfined phase, by computing the quadratic quantum fluctuations around the classical vacuum. The solution of the model has some novel features: the eigenvalues of the timelike link variable are separated in L bunches, if L is the number of links of the original lattice in the time direction, and each bunch obeys a Wigner semicircular distribution of eigenvalues. This solution becomes unstable at a critical value of the coupling constant, where it is argued that a condensation of classical solutions takes place. This can be inferred by comparison with the heat-kernel model in the Hamiltonian limit, and the related Douglas-Kazakov phase transition in QCD2. As a byproduct of our solution, we can reproduce the dependence of the coupling constant from the parameter describing the asymmetry of the lattice, and compare it to previous results by Karsch.

  14. Twisted and Nontwisted Bifurcations Induced by Diffusion

    CERN Document Server

    Lin, X B

    1996-01-01

    We discuss a diffusively perturbed predator-prey system. Freedman and Wolkowicz showed that the corresponding ODE can have a periodic solution that bifurcates from a homoclinic loop. When the diffusion coefficients are large, this solution represents a stable, spatially homogeneous time-periodic solution of the PDE. We show that when the diffusion coefficients become small, the spatially homogeneous periodic solution becomes unstable and bifurcates into spatially nonhomogeneous periodic solutions. The nature of the bifurcation is determined by the twistedness of an equilibrium/homoclinic bifurcation that occurs as the diffusion coefficients decrease. In the nontwisted case two spatially nonhomogeneous simple periodic solutions of equal period are generated, while in the twisted case a unique spatially nonhomogeneous double periodic solution is generated through period-doubling. Key Words: Reaction-diffusion equations; predator-prey systems; homoclinic bifurcations; periodic solutions.

  15. Energy release in driven twisted coronal loops

    CERN Document Server

    Bareford, M R; Browning, P K; Hood, A W

    2015-01-01

    In the present study we investigate magnetic reconnection in twisted magnetic fluxtubes with different initial configurations. In all considered cases, energy release is triggered by the ideal kink instability, which is itself the result of applying footpoint rotation to an initially potential field. The main goal of this work is to establish the influence of the field topology and various thermodynamic effects on the energy release process. Specifically, we investigate convergence of the magnetic field at the loop footpoints, atmospheric stratification, as well as thermal conduction. In all cases, the application of vortical driving at the footpoints of an initally potential field leads to an internal kink instability. With the exception of the curved loop with high footpoint convergence, the global geometry of the loop change little during the simulation. Footpoint convergence, curvature and atmospheric structure clearly influences the rapidity with which a loop achieves instability as well as the size of t...

  16. Twisted accretion discs: Pt. 5; Viscous evolution

    Energy Technology Data Exchange (ETDEWEB)

    Kumar, S. (Max-Planck-Institut fuer Physik und Astrophysik, Garching (Germany, F.R.). Inst. fuer Astrophysik)

    1990-08-15

    The time-dependence of accretion discs with orbits tilted out of the symmetry plane is studied. The effects of mass inflow modulation, and tilt variation at the disc outer edge, are examined for both circumbinary discs and for discs around compact objects. The appendices extend the numerical work to some analytic examples of tilt diffusion and external forcing effects. It is also shown that the disc must not be treated as a rigid tilted object if global angular momentum is to be conserved. These results are relevant to the problem of long-term periodicities of the light curves in Her X1 and {epsilon} Aur, the S-type symmetry of radio jets, warped gas discs in galaxies and polar rings in Neptune. Twisted discs may also arise in star-forming regions. (author).

  17. Optical twists in phase and amplitude

    DEFF Research Database (Denmark)

    Daria, Vincent R.; Palima, Darwin; Glückstad, Jesper

    2011-01-01

    beams, the far field projection of the twisted optical beam maintains a high photon concentration even at higher values of topological charge. Optical twisters have therefore profound applications to fundamental studies of light and atoms such as in quantum entanglement of the OAM, toroidal traps......Light beams with helical phase profile correspond to photons having orbital angular momentum (OAM). A Laguerre-Gaussian (LG) beam is an example where its helical phase sets a phase-singularity at the optical axis and forms a ring-shaped transverse amplitude profile. Here, we describe a unique beam...... where both phase and amplitude express a helical profile as the beam propagates in free space. Such a beam can be accurately referred to as an optical twister. We characterize optical twisters and demonstrate their capacity to induce spiral motion on particles trapped along the twisters’ path. Unlike LG...

  18. Twisted Black Hole Is Taub-NUT

    CERN Document Server

    Ong, Yen Chin

    2016-01-01

    Recently a purportedly novel solution of the vacuum Einstein field equations was discovered: it supposedly describes an asymptotically flat twisted black hole in 4-dimensions whose exterior spacetime rotates in a peculiar manner -- the frame dragging in the northern hemisphere is opposite from that of the southern hemisphere, which results in a globally vanishing angular momentum. Furthermore it was shown that the spacetime has no curvature singularity. We show that the geometry of this black hole spacetime is nevertheless not free of pathological features. In particular, it harbors a rather drastic conical singularity along the axis of rotation. In addition, there exist closed timelike curves due to the fact that the constant r and constant t surfaces are not globally Riemannian. In fact, none of these are that surprising since the solution is just the Taub-NUT geometry.

  19. Unusual presentation of twisted ovarian cyst

    Directory of Open Access Journals (Sweden)

    Vineet V Mishra

    2016-01-01

    Full Text Available Ovarian torsion (also termed as adnexal torsion refers to partial or complete rotation of the ovary and a portion of fallopian tube along its supplying vascular pedicle. It occurs commonly in reproductive age group; more on the right side (60% and often presents with acute lower abdominal pain lasting for few hours and up to 24 h, accounting for 2.7% of acute gynecological conditions. It is one of the devastating conditions, hampering blood supply of ovary which may lead to total necrosis of ovarian tissue and complications, if not diagnosed and managed in time. Hence, we present a case on a twisted ovarian cyst in postmenopausal woman with unusual symptomatology leading to delayed diagnosis and loss of an ovary.

  20. Adaptive Contour Model for Real-Time Foreground Detection

    Institute of Scientific and Technical Information of China (English)

    HUANG Ying; DING Xiaoqing

    2005-01-01

    A multiscale foreground detection method was developed to segment moving objects from a stationary background. The algorithm is based on a fixed-mesh-based contour model, which starts at the bounding box of the difference map between an input image and its background and ends at a final contour. An adaptive algorithm was developed to calculate an appropriate energy threshold to control the contours to identify the foreground silhouettes. Experiments show that this method more successfully ignores the negative influence of image noise to obtain an accurate foreground map than other foreground detection algorithms. Most shadow pixels are also eliminated by this method.

  1. Twisted boundary states in c=1 coset conformal field theories

    CERN Document Server

    Ishikawa, H; Ishikawa, Hiroshi; Yamaguchi, Atsushi

    2003-01-01

    We study the mutual consistency of twisted boundary conditions in the coset conformal field theory G/H. We calculate the overlap of the twisted boundary states of G/H with the untwisted ones, and show that the twisted boundary states are consistently defined in the diagonal modular invariant. The overlap of the twisted boundary states is expressed by the branching functions of a twisted affine Lie algebra. As a check of our argument, we study the diagonal coset theory so(2n)_1 \\oplus so(2n)_1/so(2n)_2, which is equivalent with the orbifold S^1/\\Z_2. We construct the boundary states twisted by the automorphisms of the unextended Dynkin diagram of so(2n), and show their mutual consistency by identifying their counterpart in the orbifold. For the triality of so(8), the twisted states of the coset theory correspond to neither the Neumann nor the Dirichlet boundary states of the orbifold and yield the conformal boundary states that preserve only the Virasoro algebra.

  2. Heat Transfers Enhancement with Different Square Jagged Twisted Tapes

    Directory of Open Access Journals (Sweden)

    Mr. A.V.Gawandare

    2014-03-01

    Full Text Available The present experimental work are carried out with copper twisted tape inserts 3mm with 5.2,4.2 and 3.2 twists respectively. The inserts when placed in the path of the flow of the fluid, create a high degree of turbulence resulting in an increase in the heat transfer rate and the pressure drop. The work includes the determination of friction factor and heat transfer coefficient for various twisted wire inserts with varying twists and different materials. The Reynolds number is varied from 5000 to 16000. Correlations for Nusselt number and friction factor are developed for the twisted wire inserts from the obtained results. The results of varying twists in square jagged tape with different pitches have been compared with the values for the smooth tube. The 3mm thick with 3.2 twists copper insert shows increase in Nusselt number values by 76% however there is increase in friction factor by only 19.5% as compared to the smooth tube values.

  3. Effective cross-section distribution of anisotropic piezocomposite actuators for wing twist

    Science.gov (United States)

    Cesnik, Carlos E. S.; Park, Ryan S.; Palacios, Rafael

    2003-08-01

    The twist actuation of piezocomposite actuators embedded in a composite wing is numerically investigated. Parametric analysis of the actuation authority is conducted for wing cross sections with double and triple cells, considering different distributions of anisotropic piezocomposite actuators. The variational asymptotic beam cross-sectional (VABS) analysis is used to compute the airfoil stiffness, actuation force and mass properties. As a result, the regions with the highest specific actuation are determined and a cost-effective way of adding active material to the cross section is proposed. Results indicate that 50% of the maximum mass penalty associated with the addition of active plies is responsible for generating approximately 80% of the maximum available induced twist.

  4. The Small C-terminal Domain Phosphatase 1 Inhibits Cancer Cell Migration and Invasion by Dephosphorylating Ser(P)68-Twist1 to Accelerate Twist1 Protein Degradation.

    Science.gov (United States)

    Sun, Tong; Fu, Junjiang; Shen, Tao; Lin, Xia; Liao, Lan; Feng, Xin-Hua; Xu, Jianming

    2016-05-27

    Twist1 is a basic helix-loop-helix transcription factor that strongly promotes epithelial-to-mesenchymal transition, migration, invasion, and metastasis of cancer cells. The MAPK-phosphorylated Twist1 on its serine 68 (Ser(P)(68)-Twist1) has a significantly enhanced stability and function to drive cancer cell invasion and metastasis. However, the phosphatase that dephosphorylates Ser(P)(68)-Twist1 and destabilizes Twist1 has not been identified and characterized. In this study, we screened a serine/threonine phosphatase cDNA expression library in HEK293T cells with ectopically coexpressed Twist1. We found that the small C-terminal domain phosphatase 1 (SCP1) specifically dephosphorylates Ser(P)(68)-Twist1 in both cell-free reactions and living cells. SCP1 uses its amino acid residues 43-63 to interact with the N terminus of Twist1. Increased SCP1 expression in cells decreased Ser(P)(68)-Twist1 and total Twist1 proteins, whereas knockdown of SCP1 increased Ser(P)(68)-Twist1 and total Twist1 proteins. Furthermore, the levels of SCP1 are negatively correlated with Twist1 protein levels in several cancer cell lines. SCP1-dephosphorylated Twist1 undergoes fast degradation via the ubiquitin-proteasome pathway. Importantly, an increase in SCP1 expression in breast cancer cells with either endogenous or ectopically expressed Twist1 largely inhibits the Twist1-induced epithelial-to-mesenchymal transition phenotype and the migration and invasion capabilities of these cells. These results indicate that SCP1 is the phosphatase that counterregulates the MAPK-mediated phosphorylation of Ser(68)-Twist1. Thus, an increase in SCP1 expression and activity may be a useful strategy for eliminating the detrimental roles of Twist1 in cancer cells.

  5. Accuracy of Cardiac Output by Nine Different Pulse Contour Algorithms in Cardiac Surgery Patients: A Comparison with Transpulmonary Thermodilution

    Science.gov (United States)

    Bein, Berthold; Gruenewald, Matthias; Masing, Sarah; Huenges, Katharina; Haneya, Assad; Steinfath, Markus; Renner, Jochen

    2016-01-01

    Objective. Today, there exist several different pulse contour algorithms for calculation of cardiac output (CO). The aim of the present study was to compare the accuracy of nine different pulse contour algorithms with transpulmonary thermodilution before and after cardiopulmonary bypass (CPB). Methods. Thirty patients scheduled for elective coronary surgery were studied before and after CPB. A passive leg raising maneuver was also performed. Measurements included CO obtained by transpulmonary thermodilution (COTPTD) and by nine pulse contour algorithms (COX1–9). Calibration of pulse contour algorithms was performed by esophageal Doppler ultrasound after induction of anesthesia and 15 min after CPB. Correlations, Bland-Altman analysis, four-quadrant, and polar analysis were also calculated. Results. There was only a poor correlation between COTPTD and COX1–9 during passive leg raising and in the period before and after CPB. Percentage error exceeded the required 30% limit. Four-quadrant and polar analysis revealed poor trending ability for most algorithms before and after CPB. The Liljestrand-Zander algorithm revealed the best reliability. Conclusions. Estimation of CO by nine different pulse contour algorithms revealed poor accuracy compared with transpulmonary thermodilution. Furthermore, the less-invasive algorithms showed an insufficient capability for trending hemodynamic changes before and after CPB. The Liljestrand-Zander algorithm demonstrated the highest reliability. This trial is registered with NCT02438228 (ClinicalTrials.gov).

  6. Disambiguating the roles of area V1 and the lateral occipital complex (LOC) in contour integration.

    Science.gov (United States)

    Shpaner, Marina; Molholm, Sophie; Forde, Emmajane; Foxe, John J

    2013-04-01

    Contour integration, the linking of collinear but disconnected visual elements across space, is an essential facet of object and scene perception. Here, we set out to arbitrate between two previously advanced mechanisms of contour integration: serial facilitative interactions between collinear cells in the primary visual cortex (V1) versus pooling of inputs in higher-order visual areas. To this end, we used high-density electrophysiological recordings to assess the spatio-temporal dynamics of brain activity in response to Gabor contours embedded in Gabor noise (so-called "pathfinder displays") versus control stimuli. Special care was taken to elicit and detect early activity stemming from the primary visual cortex, as indexed by the C1 component of the visual evoked potential. Arguing against a purely early V1 account, there was no evidence for contour-related modulations within the C1 timeframe (50-100 ms). Rather, the earliest effects were observed within the timeframe of the N1 component (160-200 ms) and inverse source analysis pointed to principle generators in the lateral occipital complex (LOC) within the ventral visual stream. Source anlaysis also suggested that it was only during this relatively late processing period that contextual effects emerged in hierarchically early visual regions (i.e. V1/V2), consistent with a more distributed process involving recurrent feedback/feedforward interactions between LOC and early visual sensory regions. The distribution of effects uncovered here is consistent with pooling of information in higher order cortical areas as the initial step in contour integration, and that this pooling occurs relatively late in processing rather than during the initial sensory-processing period.

  7. A 3D interactive multi-object segmentation tool using local robust statistics driven active contours.

    Science.gov (United States)

    Gao, Yi; Kikinis, Ron; Bouix, Sylvain; Shenton, Martha; Tannenbaum, Allen

    2012-08-01

    Extracting anatomical and functional significant structures renders one of the important tasks for both the theoretical study of the medical image analysis, and the clinical and practical community. In the past, much work has been dedicated only to the algorithmic development. Nevertheless, for clinical end users, a well designed algorithm with an interactive software is necessary for an algorithm to be utilized in their daily work. Furthermore, the software would better be open sourced in order to be used and validated by not only the authors but also the entire community. Therefore, the contribution of the present work is twofolds: first, we propose a new robust statistics based conformal metric and the conformal area driven multiple active contour framework, to simultaneously extract multiple targets from MR and CT medical imagery in 3D. Second, an open source graphically interactive 3D segmentation tool based on the aforementioned contour evolution is implemented and is publicly available for end users on multiple platforms. In using this software for the segmentation task, the process is initiated by the user drawn strokes (seeds) in the target region in the image. Then, the local robust statistics are used to describe the object features, and such features are learned adaptively from the seeds under a non-parametric estimation scheme. Subsequently, several active contours evolve simultaneously with their interactions being motivated by the principles of action and reaction-this not only guarantees mutual exclusiveness among the contours, but also no longer relies upon the assumption that the multiple objects fill the entire image domain, which was tacitly or explicitly assumed in many previous works. In doing so, the contours interact and converge to equilibrium at the desired positions of the desired multiple objects. Furthermore, with the aim of not only validating the algorithm and the software, but also demonstrating how the tool is to be used, we provide

  8. Tri-bimaximal mixing from twisted Friedberg-Lee symmetry

    Energy Technology Data Exchange (ETDEWEB)

    Araki, Takeshi [National Tsing Hua University, Department of Physics, Hsinchu (China); Takahashi, Ryo [Osaka University, Department of Physics, Graduate School of Science, Osaka (Japan)

    2009-10-15

    We investigate the Friedberg-Lee (FL) symmetry and its promotion to include the {mu}-{tau} symmetry, and call this the twisted FL symmetry. Based on the twisted FL symmetry, two possible schemes are presented toward the realistic neutrino mass spectrum and the tri-bimaximal mixing. In the first scheme, we suggest the semi-uniform translation of the FL symmetry. The second one is based on the S{sub 3} permutation family symmetry. The breaking terms, which are twisted FL symmetric, are introduced. Some viable models in each scheme are also presented. (orig.)

  9. Tri-bimaximal mixing from twisted Friedberg-Lee symmetry

    Science.gov (United States)

    Araki, Takeshi; Takahashi, Ryo

    2009-10-01

    We investigate the Friedberg-Lee (FL) symmetry and its promotion to include the μ- τ symmetry, and call this the twisted FL symmetry. Based on the twisted FL symmetry, two possible schemes are presented toward the realistic neutrino mass spectrum and the tri-bimaximal mixing. In the first scheme, we suggest the semi-uniform translation of the FL symmetry. The second one is based on the S 3 permutation family symmetry. The breaking terms, which are twisted FL symmetric, are introduced. Some viable models in each scheme are also presented.

  10. Assembly and Folding of Twisted Baskets in Organic Solvents.

    Science.gov (United States)

    Pratumyot, Yaowalak; Chen, Shigui; Hu, Lei; Polen, Shane M; Hadad, Christopher M; Badjić, Jovica D

    2016-09-02

    A synthetic method for obtaining enantiopure and twisted baskets of type (P)-3 is described. These chiral cavitands were found to fold quinoline gates, at the rim of their twisted platform, in acetonitrile and give molecular capsules that assemble into large unilamellar vesicles. In a less polar dichloromethane, however, cup-shaped (P)-3 packed into vesicles but with the quinoline gates in an unfolded orientation. The ability of twisted baskets to form functional nanostructured materials could be of interest for building stereoselective sensors and catalysts.

  11. TWIST1 promotes invasion through mesenchymal change in human glioblastoma

    Directory of Open Access Journals (Sweden)

    Wakimoto Hiroaki

    2010-07-01

    Full Text Available Abstract Background Tumor cell invasion into adjacent normal brain is a mesenchymal feature of GBM and a major factor contributing to their dismal outcomes. Therefore, better understandings of mechanisms that promote mesenchymal change in GBM are of great clinical importance to address invasion. We previously showed that the bHLH transcription factor TWIST1 which orchestrates carcinoma metastasis through an epithelial mesenchymal transition (EMT is upregulated in GBM and promotes invasion of the SF767 GBM cell line in vitro. Results To further define TWIST1 functions in GBM we tested the impact of TWIST1 over-expression on invasion in vivo and its impact on gene expression. We found that TWIST1 significantly increased SNB19 and T98G cell line invasion in orthotopic xenotransplants and increased expression of genes in functional categories associated with adhesion, extracellular matrix proteins, cell motility and locomotion, cell migration and actin cytoskeleton organization. Consistent with this TWIST1 reduced cell aggregation, promoted actin cytoskeletal re-organization and enhanced migration and adhesion to fibronectin substrates. Individual genes upregulated by TWIST1 known to promote EMT and/or GBM invasion included SNAI2, MMP2, HGF, FAP and FN1. Distinct from carcinoma EMT, TWIST1 did not generate an E- to N-cadherin "switch" in GBM cell lines. The clinical relevance of putative TWIST target genes SNAI2 and fibroblast activation protein alpha (FAP identified in vitro was confirmed by their highly correlated expression with TWIST1 in 39 human tumors. The potential therapeutic importance of inhibiting TWIST1 was also shown through a decrease in cell invasion in vitro and growth of GBM stem cells. Conclusions Together these studies demonstrated that TWIST1 enhances GBM invasion in concert with mesenchymal change not involving the canonical cadherin switch of carcinoma EMT. Given the recent recognition that mesenchymal change in GBMs is

  12. Topological duality twist and brane instantons in F-theory

    Energy Technology Data Exchange (ETDEWEB)

    Martucci, Luca [Dipartimento di Fisica ed Astronomia “Galileo Galilei”, Università di Padova andINFN - Sezione di Padova,Via Marzolo 8, I-35131 Padova (Italy)

    2014-06-30

    A variant of the topological twist, involving SL(2,ℤ) dualities and hence named topological duality twist, is introduced and explicitly applied to describe a U(1) N=4 super Yang-Mills theory on a Kähler space with holomorphically space-dependent coupling. Three-dimensional duality walls and two-dimensional chiral theories naturally enter the formulation of the duality twisted theory. Appropriately generalized, this theory is relevant for the study of Euclidean D3-brane instantons in F-theory compactifications. Some of its properties and implications are discussed.

  13. Twist Neutrality and the Diameter of the Nucleosome Core Particle

    DEFF Research Database (Denmark)

    Bohr, Jakob; Olsen, Kasper

    2012-01-01

    The diameter of the nucleosome core particle is the same for all the eukaryotes. Here we discuss the possibility that this selectiveness is consistent with a propensity for twist neutrality, in particular, for the double helical DNA to stay rotationally neutral when strained. Reorganization of DNA...... cannot be done without some level of temporal tensile stress, and as a consequence chiral molecules, such as helices, will twist under strain. The requirement that the nucleosome, constituting the nucleosome core particle and linker DNA, has a vanishing strain-twist coupling leads to a requirement...

  14. Differential forms and {kappa}-Minkowski spacetime from extended twist

    Energy Technology Data Exchange (ETDEWEB)

    Juric, Tajron; Meljanac, Stjepan [Rudjer Boskovic Institute, Zagreb (Croatia); Strajn, Rina [Jacobs University Bremen, Bremen (Germany)

    2013-07-15

    We analyze bicovariant differential calculus on {kappa}-Minkowski spacetime. It is shown that corresponding Lorentz generators and noncommutative coordinates compatible with bicovariant calculus cannot be realized in terms of commutative coordinates and momenta. Furthermore, {kappa}-Minkowski space and NC forms are constructed by twist related to a bicrossproduct basis. It is pointed out that the consistency condition is not satisfied. We present the construction of {kappa}-deformed coordinates and forms (super-Heisenberg algebra) using extended twist. It is compatible with bicovariant differential calculus with {kappa}-deformed igl(4)-Hopf algebra. The extended twist leading to {kappa}-Poincare-Hopf algebra is also discussed. (orig.)

  15. Adaptive Aggregation-based Domain Decomposition Multigrid for Twisted Mass Fermions

    CERN Document Server

    Alexandrou, Constantia; Finkenrath, Jacob; Frommer, Andreas; Kahl, Karsten; Rottmann, Matthias

    2016-01-01

    The Adaptive Aggregation-based Domain Decomposition Multigrid method (arXiv:1303.1377) is extended for two degenerate flavors of twisted mass fermions. By fine-tuning the parameters we achieve a speed-up of the order of hundred times compared to the conjugate gradient algorithm for the physical value of the pion mass. A thorough analysis of the aggregation parameters is presented, which provides a novel insight into multigrid methods for lattice QCD independently of the fermion discretization.

  16. Bathymetric Contours for Prairie Rose Lake, Shelby County, Iowa

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — This data set consists of digital bathymetry contours for Prairie Rose Lake in Shelby Co., Iowa. The U.S. Geological Survey conducted a bathymetric survey of...

  17. Bathymetric Contours for Lake Minnewashta, Dickinson County, Iowa

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — This data set consists of digital bathymetry contours for Lake Minnewashta in Dickinson Co., Iowa. The U.S. Geological Survey conducted a bathymetric survey of Lake...

  18. Bathymetric Contours for Littlefield Lake, Audubon County, Iowa

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — This data set consists of digital bathymetry contours for Littlefield Lake in Audubon Co., Iowa. The U.S. Geological Survey conducted a bathymetric survey of...

  19. Bathymetric Contours for Nine Eagles Lake, Decatur County, Iowa

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — This data set consists of digital bathymetry contours for Nine Eagles Lake in Decatur Co., Iowa. The U.S. Geological Survey conducted a bathymetric survey of Nine...

  20. Transgressive Contours--Salt Point to Drakes Bay, California

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — This part of DS 781 presents data for the transgressive contours for the Salt Point to Drakes Bay, California, region. The vector file is included in...