Generating triangulated macromolecular surfaces by Euclidean Distance Transform.
Directory of Open Access Journals (Sweden)
Dong Xu
Full Text Available Macromolecular surfaces are fundamental representations of their three-dimensional geometric shape. Accurate calculation of protein surfaces is of critical importance in the protein structural and functional studies including ligand-protein docking and virtual screening. In contrast to analytical or parametric representation of macromolecular surfaces, triangulated mesh surfaces have been proved to be easy to describe, visualize and manipulate by computer programs. Here, we develop a new algorithm of EDTSurf for generating three major macromolecular surfaces of van der Waals surface, solvent-accessible surface and molecular surface, using the technique of fast Euclidean Distance Transform (EDT. The triangulated surfaces are constructed directly from volumetric solids by a Vertex-Connected Marching Cube algorithm that forms triangles from grid points. Compared to the analytical result, the relative error of the surface calculations by EDTSurf is <2-4% depending on the grid resolution, which is 1.5-4 times lower than the methods in the literature; and yet, the algorithm is faster and costs less computer memory than the comparative methods. The improvements in both accuracy and speed of the macromolecular surface determination should make EDTSurf a useful tool for the detailed study of protein docking and structure predictions. Both source code and the executable program of EDTSurf are freely available at http://zhang.bioinformatics.ku.edu/EDTSurf.
GENERATE TRIANGULATED SURFACES FROM MASSIVE UNORGANIZED POINTS
Institute of Scientific and Technical Information of China (English)
无
2006-01-01
A region-growing method for reconstructing triangulated surfaces from massive unorganized points is presented. To save memory space, a ring data-structure is adopted to build connections between points and triangulated surfaces. The data-structure allows the efficient retrieval of all neighboring vertices and triangles of a given vertice. To narrow the search range of adjacent points and avoid triangle intersection, an influence area is defined for each active-edge. In the region-growing process of triangulated surfaces, a minimum-edge-angle-product algorithm is put forward to select an appropriate point to form a new triangle for an active edge. Results indicate that the presented method has high efficiency and needs less memory space, optimized triangulated surfaces with reliable topological quality can be obtained after triangulation.
Adaptive mesh generation for viscous flows using Delaunay triangulation
Mavriplis, Dimitri J.
1990-01-01
A method for generating an unstructured triangular mesh in two dimensions, suitable for computing high Reynolds number flows over arbitrary configurations is presented. The method is based on a Delaunay triangulation, which is performed in a locally stretched space, in order to obtain very high aspect ratio triangles in the boundary layer and the wake regions. It is shown how the method can be coupled with an unstructured Navier-Stokes solver to produce a solution adaptive mesh generation procedure for viscous flows.
Hex-dominant mesh generation using 3D constrained triangulation
Energy Technology Data Exchange (ETDEWEB)
OWEN,STEVEN J.
2000-05-30
A method for decomposing a volume with a prescribed quadrilateral surface mesh, into a hexahedral-dominated mesh is proposed. With this method, known as Hex-Morphing (H-Morph), an initial tetrahedral mesh is provided. Tetrahedral are transformed and combined starting from the boundary and working towards the interior of the volume. The quadrilateral faces of the hexahedra are treated as internal surfaces, which can be recovered using constrained triangulation techniques. Implementation details of the edge and face recovery process are included. Examples and performance of the H-Morph algorithm are also presented.
Automatic Generation of CFD-Ready Surface Triangulations from CAD Geometry
Aftosmis, M. J.; Delanaye, M.; Haimes, R.; Nixon, David (Technical Monitor)
1998-01-01
This paper presents an approach for the generation of closed manifold surface triangulations from CAD geometry. CAD parts and assemblies are used in their native format, without translation, and a part's native geometry engine is accessed through a modeler-independent application programming interface (API). In seeking a robust and fully automated procedure, the algorithm is based on a new physical space manifold triangulation technique which was developed to avoid robustness issues associated with poorly conditioned mappings. In addition, this approach avoids the usual ambiguities associated with floating-point predicate evaluation on constructed coordinate geometry in a mapped space, The technique is incremental, so that each new site improves the triangulation by some well defined quality measure. Sites are inserted using a variety of priority queues to ensure that new insertions will address the worst triangles first, As a result of this strategy, the algorithm will return its 'best' mesh for a given (prespecified) number of sites. Alternatively, the algorithm may be allowed to terminate naturally after achieving a prespecified measure of mesh quality. The resulting triangulations are 'CFD-ready' in that: (1) Edges match the underlying part model to within a specified tolerance. (2) Triangles on disjoint surfaces in close proximity have matching length-scales. (3) The algorithm produces a triangulation such that no angle is less than a given angle bound, alpha, or greater than Pi - 2alpha This result also sets bounds on the maximum vertex degree, triangle aspect-ratio and maximum stretching rate for the triangulation. In addition to tile output triangulations for a variety of CAD parts, tile discussion presents related theoretical results which assert the existence of such all angle bound, and demonstrate that maximum bounds of between 25 deg and 30 deg may be achieved in practice.
A tuned mesh-generation strategy for image representation based on data-dependent triangulation.
Li, Ping; Adams, Michael D
2013-05-01
A mesh-generation framework for image representation based on data-dependent triangulation is proposed. The proposed framework is a modified version of the frameworks of Rippa and Garland and Heckbert that facilitates the development of more effective mesh-generation methods. As the proposed framework has several free parameters, the effects of different choices of these parameters on mesh quality are studied, leading to the recommendation of a particular set of choices for these parameters. A mesh-generation method is then introduced that employs the proposed framework with these best parameter choices. This method is demonstrated to produce meshes of higher quality (both in terms of squared error and subjectively) than those generated by several competing approaches, at a relatively modest computational and memory cost.
Denzin, Norman K.
2012-01-01
The author's thesis is simple and direct. Those in the mixed methods qualitative inquiry community need a new story line, one that does not confuse pragmatism for triangulation, and triangulation for mixed methods research (MMR). A different third way is required, one that inspires generative politics and dialogic democracy and helps shape…
Denzin, Norman K.
2012-01-01
The author's thesis is simple and direct. Those in the mixed methods qualitative inquiry community need a new story line, one that does not confuse pragmatism for triangulation, and triangulation for mixed methods research (MMR). A different third way is required, one that inspires generative politics and dialogic democracy and helps shape…
Triangulated categories (AM-148)
Neeman, Amnon
2014-01-01
The first two chapters of this book offer a modern, self-contained exposition of the elementary theory of triangulated categories and their quotients. The simple, elegant presentation of these known results makes these chapters eminently suitable as a text for graduate students. The remainder of the book is devoted to new research, providing, among other material, some remarkable improvements on Brown''s classical representability theorem. In addition, the author introduces a class of triangulated categories""--the ""well generated triangulated categories""--and studies their properties. This
Delaunay triangulation and computational fluid dynamics meshes
Posenau, Mary-Anne K.; Mount, David M.
1992-01-01
In aerospace computational fluid dynamics (CFD) calculations, the Delaunay triangulation of suitable quadrilateral meshes can lead to unsuitable triangulated meshes. Here, we present case studies which illustrate the limitations of using structured grid generation methods which produce points in a curvilinear coordinate system for subsequent triangulations for CFD applications. We discuss conditions under which meshes of quadrilateral elements may not produce a Delaunay triangulation suitable for CFD calculations, particularly with regard to high aspect ratio, skewed quadrilateral elements.
Institute of Scientific and Technical Information of China (English)
周雪梅; 黎应飞
2013-01-01
TIN(Triangulated Irregular Network) has better performance on shaping terrain. The generation algorithm has been great concerned. This paper has discussed the data structure design of triangulation, and designed and implemented the algorithm based on Bowyer-Watson idea that is an incremental insertion algorithm. This paper analyzes why the algorithms may arise the phenomenon of cross during the experiment, and gives the improved idea. The improved algorithm has been used to visualize the terrain modeling, to obtain good results, for the research triangulation has some value.%不规则三角网(Triangulated Irregular Network,TIN)在表示地形的形态方面具有较好的表现,其生成算法一直备受关注.讨论了三角网的数据结构的设计,采用逐点插入算法中的Bowyer-Watson算法思想为研究重点,设计并实现了该算法,对算法实验过程中可能出现的交叉现象进行分析,给出算法的改进.该改进算法已用于地形的可视化建模中,获得了较好的效果,对于三角剖分的相关研究具有一定的价值.
Triangulating Trimmed NURBS Surfaces
2000-01-01
Curve and Surface Design: Saint-Malo 1999 381 Pierre-Jean Laurent, Paul Sablonnibre, and Larry L. Schumaker ( eds .), pp. 381-388. Copyright 0 2000 by...the boundary of its neighboring surface. References 1. Baehmann, P. L., S. L. Wittchen , M. S. Shephard, K. R. Grice and M. A. Yerry, Robust...and D. Eppstein, Mesh generation and optimal triangulation, in Computing in Euclidean Geometry, 2nd ed ., D.-Z. Du and F. K. Hwang, ( eds .), World
OPTIMAL DELAUNAY TRIANGULATIONS
Institute of Scientific and Technical Information of China (English)
Long Chen; Jin-chao Xu
2004-01-01
The Delaunay triangulation, in both classic and more generalized sense, is studied in this paper for minimizing the linear interpolation error (measure in Lp-norm) for a given function. The classic Delaunay triangulation can then be characterized as an optimal triangulation that minimizes the interpolation error for the isotropic function ‖x‖2 among all the triangulations with a given set of vertices. For a more general function, a functiondependent Delaunay triangulation is then defined to be an optimal triangulation that minimizes the interpolation error for this .function and its construction can be obtained by a simple lifting and projection procedure.The optimal Delaunay triangulation is the one that minimizes the interpolation error among all triangulations with the same number of vertices, i.e. the distribution of vertices are optimized in order to minimize the interpolation error. Such a function-dependent optimal Delaunay triangulation is proved to exist for any given convex continuous function.On an optimal Delaunay triangulation associated with f, it is proved that ▽f at the interior vertices can be exactly recovered by the function values on its neighboring vertices.Since the optimal Delaunay triangulation is difficult to obtain in practice, the concept of nearly optimal triangulation is introduced and two sufficient conditions are presented for a triangulation to be nearly optimal.
Minimal triangulations of simplotopes
Seacrest, Tyler
2009-01-01
We derive lower bounds for the size of simplicial covers of simplotopes, which are products of simplices. These also serve as lower bounds for triangulations of such polytopes, including triangulations with interior vertices. We establish that a minimal triangulation of a product of two simplices is given by a vertex triangulation, i.e., one without interior vertices. For products of more than two simplices, we produce bounds for products of segments and triangles. Our analysis yields linear programs that arise from considerations of covering exterior faces and exploiting the product structure of these polytopes. Aside from cubes, these are the first known lower bounds for triangulations of simplotopes with three or more factors. We also construct a minimal triangulation for the product of a triangle and a square, and compare it to our lower bound.
Triangulation of NURBS Surfaces
Samareh-Abolhassani, Jamshid
1994-01-01
A technique is presented for triangulation of NURBS surfaces. This technique is built upon an advancing front technique combined with grid point projection. This combined approach has been successfully implemented for structured and unstructured grids.
Triangulation of NURBS Surfaces
Samareh-Abolhassani, Jamshid
1994-01-01
A technique is presented for triangulation of NURBS surfaces. This technique is built upon an advancing front technique combined with grid point projection. This combined approach has been successfully implemented for structured and unstructured grids.
Data Reduction and Triangulation Approach to Scattered Points
Institute of Scientific and Technical Information of China (English)
JIANG Dan; WANG Lan-cheng
2004-01-01
For the generation of the model in reverse engineering, a laser scanner is currently used a lot due to the fast measuring speed and high precision. Direct triangulation of data points captured from a physical object has a great advantage in that it can reduce the time and error in modeling process. It is important to reduce the number of data points for triangulating points with maintaining precision. To triangulate data points within a tolerance ε a new approach is developed in this paper. Different level of triangulations can be generated directly from data points using the proposed strategy that reduces and triangulates data points based on triangulation of 3D parametric surfaces. An experimental example is presented to demonstrate the effectiveness and efficiency of the proposed algorithm.
Tokunaga, Fuminori; Goto, Eiji; Komatsu, Ginga; Saeki, Yasushi; Tanaka, Keiji; Takahashi, Hirotaka; Sawasaki, Tatsuya; Inoue, Satoshi; Oshiumi, Hiroyuki; Seya, Tsukasa; Nakano, Hiroyasu; Tanaka, Yuetsu; Iwai, Kazuhiro
2017-01-01
The Tax protein of human T-cell leukemia virus type 1 (HTLV-1) is crucial for the development of adult T-cell leukemia (ATL), a highly malignant CD4+ T cell neoplasm. Among the multiple aberrant Tax-induced effects on cellular processes, persistent activation of transcription factor NF-κB, which is activated only transiently upon physiological stimulation, is essential for leukemogenesis. We and others have shown that Tax induces activation of the IκB kinase (IKK) complex, which is a critical step in NF-κB activation, by generating Lys63-linked polyubiquitin chains. However, the molecular mechanism underlying Tax-induced IKK activation is controversial and not fully understood. Here, we demonstrate that Tax recruits linear (Met1-linked) ubiquitin chain assembly complex (LUBAC) to the IKK complex and that Tax fails to induce IKK activation in cells that lack LUBAC activity. Mass spectrometric analyses revealed that both Lys63-linked and Met1-linked polyubiquitin chains are associated with the IKK complex. Furthermore, treatment of the IKK-associated polyubiquitin chains with Met1-linked-chain-specific deubiquitinase (OTULIN) resulted in the reduction of high molecular weight polyubiquitin chains and the generation of short Lys63-linked ubiquitin chains, indicating that Tax can induce the generation of Lys63- and Met1-linked hybrid polyubiquitin chains. We also demonstrate that Tax induces formation of the active macromolecular IKK complex and that the blocking of Tax-induced polyubiquitin chain synthesis inhibited formation of the macromolecular complex. Taken together, these results lead us to propose a novel model in which the hybrid-chain-dependent oligomerization of the IKK complex triggered by Tax leads to trans-autophosphorylation-mediated IKK activation. PMID:28103322
Shibata, Yuri; Tokunaga, Fuminori; Goto, Eiji; Komatsu, Ginga; Gohda, Jin; Saeki, Yasushi; Tanaka, Keiji; Takahashi, Hirotaka; Sawasaki, Tatsuya; Inoue, Satoshi; Oshiumi, Hiroyuki; Seya, Tsukasa; Nakano, Hiroyasu; Tanaka, Yuetsu; Iwai, Kazuhiro; Inoue, Jun-Ichiro
2017-01-01
The Tax protein of human T-cell leukemia virus type 1 (HTLV-1) is crucial for the development of adult T-cell leukemia (ATL), a highly malignant CD4+ T cell neoplasm. Among the multiple aberrant Tax-induced effects on cellular processes, persistent activation of transcription factor NF-κB, which is activated only transiently upon physiological stimulation, is essential for leukemogenesis. We and others have shown that Tax induces activation of the IκB kinase (IKK) complex, which is a critical step in NF-κB activation, by generating Lys63-linked polyubiquitin chains. However, the molecular mechanism underlying Tax-induced IKK activation is controversial and not fully understood. Here, we demonstrate that Tax recruits linear (Met1-linked) ubiquitin chain assembly complex (LUBAC) to the IKK complex and that Tax fails to induce IKK activation in cells that lack LUBAC activity. Mass spectrometric analyses revealed that both Lys63-linked and Met1-linked polyubiquitin chains are associated with the IKK complex. Furthermore, treatment of the IKK-associated polyubiquitin chains with Met1-linked-chain-specific deubiquitinase (OTULIN) resulted in the reduction of high molecular weight polyubiquitin chains and the generation of short Lys63-linked ubiquitin chains, indicating that Tax can induce the generation of Lys63- and Met1-linked hybrid polyubiquitin chains. We also demonstrate that Tax induces formation of the active macromolecular IKK complex and that the blocking of Tax-induced polyubiquitin chain synthesis inhibited formation of the macromolecular complex. Taken together, these results lead us to propose a novel model in which the hybrid-chain-dependent oligomerization of the IKK complex triggered by Tax leads to trans-autophosphorylation-mediated IKK activation.
Advancing-Front Algorithm For Delaunay Triangulation
Merriam, Marshal L.
1993-01-01
Efficient algorithm performs Delaunay triangulation to generate unstructured grids for use in computing two-dimensional flows. Once grid generated, one can optionally call upon additional subalgorithm that removes diagonal lines from quadrilateral cells nearly rectangular. Resulting approximately rectangular grid reduces cost per iteration of flow-computing algorithm.
Advancing-Front Algorithm For Delaunay Triangulation
Merriam, Marshal L.
1993-01-01
Efficient algorithm performs Delaunay triangulation to generate unstructured grids for use in computing two-dimensional flows. Once grid generated, one can optionally call upon additional subalgorithm that removes diagonal lines from quadrilateral cells nearly rectangular. Resulting approximately rectangular grid reduces cost per iteration of flow-computing algorithm.
Oostrom, V. van; Zantema, Hans
2012-01-01
We introduce a process, dubbed triangulation, turning any rewrite relation into a confluent one. It is more direct than usual completion, in the sense that objects connected by a peak are directly oriented rather than their normal forms. We investigate conditions under which this process preserves d
Triangulation in aetiological epidemiology.
Lawlor, Debbie A; Tilling, Kate; Davey Smith, George
2016-12-01
Triangulation is the practice of obtaining more reliable answers to research questions through integrating results from several different approaches, where each approach has different key sources of potential bias that are unrelated to each other. With respect to causal questions in aetiological epidemiology, if the results of different approaches all point to the same conclusion, this strengthens confidence in the finding. This is particularly the case when the key sources of bias of some of the approaches would predict that findings would point in opposite directions if they were due to such biases. Where there are inconsistencies, understanding the key sources of bias of each approach can help to identify what further research is required to address the causal question. The aim of this paper is to illustrate how triangulation might be used to improve causal inference in aetiological epidemiology. We propose a minimum set of criteria for use in triangulation in aetiological epidemiology, summarize the key sources of bias of several approaches and describe how these might be integrated within a triangulation framework. We emphasize the importance of being explicit about the expected direction of bias within each approach, whenever this is possible, and seeking to identify approaches that would be expected to bias the true causal effect in different directions. We also note the importance, when comparing results, of taking account of differences in the duration and timing of exposures. We provide three examples to illustrate these points. © The Author 2017. Published by Oxford University Press on behalf of the International Epidemiological Association.
Oostrom, V. van; Zantema, Hans
2012-01-01
We introduce a process, dubbed triangulation, turning any rewrite relation into a confluent one. It is more direct than usual completion, in the sense that objects connected by a peak are directly oriented rather than their normal forms. We investigate conditions under which this process preserves d
Wang, Jianxin Steven
The long-term objective is to develop magnetic resonance (MR) contrast agents that actively and passively target tumors for diagnosis and therapy. Many diagnostic imaging techniques for cancer lack specificity. A dendrimer based magnetic resonance imaging contrast agent has been developed with large proton relaxation enhancements and high molecular relaxivities. A new type of linear dendrimer based MRI contrast agent that is built from the polypropyleneimine and polyamidoamine dendrimers in which free amines have been conjugated to the chelate DTPA, which further formed the complex with Gadolinium (Gd) was studied. The specific research goals were to test the hypothesis that a linear chelate with macromolecular agents can be used in vitro and in vivo. This work successfully examined the adequacy and viability of the application for this agent in vitro and in vivo. A small animal whole body counter was designed and constructed to allow us to monitor biodistribution and kinetic mechanisms using a radioisotope labeled complex. The procedures of metal labeling, separation and purification have been established from this work. A biodistribution study has been performed using radioisotope induced organ/tissue counting and gamma camera imaging. The ratio of percentage of injected dose per gram organ/tissue for kidney and liver is 3.71 from whole body counter and 3.77 from the gamma camera. The results suggested that retention of Gd (III) is too high and a more kinetically stable chelate should be developed. The pharmacokinetic was evaluated in the whole animal model with the whole body clearance, and a kinetics model was developed. The pharmacokinetic results showed a bi-exponential decay in the animal model with two component excretion constants 1.43e(-5) and 0.0038511, which give half-lives of 3 hours and 33.6 days, respectively. Magnetic resonance imaging of this complex resulted in a 52% contrast enhancement in the rat kidney following the agents' administration in
IMPROVED DELAUNAY TRIANGULATION FOR TRIMMED NURBS SURFACE
Institute of Scientific and Technical Information of China (English)
SUNKe-hao
2004-01-01
An improved algorithm of Delaunay triangulation is proposed by expanding the scope from a convex polygon to an arbitrary polygon area in which holes can be contained in the subdivision procedure. The data structure of generated triangles and the exuviationslike method play a key role, and a single connectivity domain (SCD) without holes is constructed as the initial part of the algorithm. Meanwhile, some examples show that the method can be applied to the triangulation of the trimmed NURBS surface. The result of surface tessellation can be used in many applications such as NC machining, finite element analysis, rendering and mechanism interference detection.
Advanced Triangulation Displacement Sensors
Poteet, Wade M.; Cauthen, Harold K.
1996-01-01
Advanced optoelectronic triangulation displacement sensors undergoing development. Highly miniaturized, more stable, more accurate, and relatively easy to use. Incorporate wideband electronic circuits suitable for real-time monitoring and control of displacements. Measurements expected to be accurate to within nanometers. In principle, sensors mass-produced at relatively low unit cost. Potential applications numerous. Possible industrial application in measuring runout of rotating shaft or other moving part during fabrication in "zero-defect" manufacturing system, in which measured runout automatically corrected.
Advanced Triangulation Displacement Sensors
Poteet, Wade M.; Cauthen, Harold K.
1996-01-01
Advanced optoelectronic triangulation displacement sensors undergoing development. Highly miniaturized, more stable, more accurate, and relatively easy to use. Incorporate wideband electronic circuits suitable for real-time monitoring and control of displacements. Measurements expected to be accurate to within nanometers. In principle, sensors mass-produced at relatively low unit cost. Potential applications numerous. Possible industrial application in measuring runout of rotating shaft or other moving part during fabrication in "zero-defect" manufacturing system, in which measured runout automatically corrected.
A TQFT of Turaev-Viro type on shaped triangulations
Kashaev, Rinat; Vartanov, Grigory
2012-01-01
A shaped triangulation is a finite triangulation of an oriented pseudo three manifold where each tetrahedron carries dihedral angles of an ideal hyberbolic tetrahedron. To each shaped triangulation, we associate a quantum partition function in the form of an absolutely convergent state integral which is invariant under shaped 3-2 Pachner moves and invariant with respect to shape gauge transformations generated by total dihedral angles around internal edges through the Neumann-Zagier Poisson bracket. Similarly to Turaev-Viro theory, the state variables live on edges of the triangulation but take their values on the whole real axis. The tetrahedral weight functions are composed of three hyperbolic gamma functions in a way that they enjoy a manifest tetrahedral symmetry. We conjecture that for shaped triangulations of closed 3-manifolds, our partition function is twice the absolute value squared of the partition function of Techm\\"uller TQFT defined by Andersen and Kashaev. This is similar to the known relations...
Onomatopoeia characters extraction from comic images using constrained Delaunay triangulation
Liu, Xiangping; Shoji, Kenji; Mori, Hiroshi; Toyama, Fubito
2014-02-01
A method for extracting onomatopoeia characters from comic images was developed based on stroke width feature of characters, since they nearly have a constant stroke width in a number of cases. An image was segmented with a constrained Delaunay triangulation. Connected component grouping was performed based on the triangles generated by the constrained Delaunay triangulation. Stroke width calculation of the connected components was conducted based on the altitude of the triangles generated with the constrained Delaunay triangulation. The experimental results proved the effectiveness of the proposed method.
Observation, innovation and triangulation
DEFF Research Database (Denmark)
Hetmar, Vibeke
2007-01-01
In the article the focus is on classroom research which aims at offering some evidence-based description of the interplay between the logic of practice in school and schooling on the one hand and the teachers' efforts to realize notions of innovation and change on the other hand. Based...... on experiences from a pilot project in three different classrooms methodological possibilities and problems are presented and discussed: 1) educational criticism, including the concepts of positions, perspectives and connoisseurship, 2) classroom observations and 3) triangulation as a methodological tool....
The use of triangulation in qualitative research.
Carter, Nancy; Bryant-Lukosius, Denise; DiCenso, Alba; Blythe, Jennifer; Neville, Alan J
2014-09-01
Triangulation refers to the use of multiple methods or data sources in qualitative research to develop a comprehensive understanding of phenomena (Patton, 1999). Triangulation also has been viewed as a qualitative research strategy to test validity through the convergence of information from different sources. Denzin (1978) and Patton (1999) identified four types of triangulation: (a) method triangulation, (b) investigator triangulation, (c) theory triangulation, and (d) data source triangulation. The current article will present the four types of triangulation followed by a discussion of the use of focus groups (FGs) and in-depth individual (IDI) interviews as an example of data source triangulation in qualitative inquiry.
Land Elevation TINs (Triangulated Irregular Networks) for Jefferson County, WI
Federal Emergency Management Agency, Department of Homeland Security — The Land Elevation TINs (Triangulated Irregular Networks) in this directory are generated from 2 foot contour lines from Jefferson County. Little is known about the...
Pamplona, Reinald; Barja, Gustavo
2007-10-01
Key characteristics relating oxidative damage to aging and longevity are reviewed. Available information indicates that the specific composition of tissue macromolecules (proteins, lipids and mitochondrial DNA) in long-lived animal species gives them an intrinsically high resistance to modification that likely contributes to the superior longevity of these species. This is obtained in the case of lipids by decreasing fatty acid unsaturation, and in the proteins by lowering their methionine content. Long-lived animals also show low rates of reactive oxygen species (ROS) generation and oxidative damage at their mitochondria. On the other hand, dietary restriction decreases mitochondrial ROS production and oxidative damage to mitochondrial DNA and proteins. These changes are due to the decreased intake of dietary proteins (not of lipids or carbohydrates) of the dietary restricted animals. In turn, these effects of protein restriction seem to be specifically due to the lowered methionine intake of the protein and dietary restricted animals. It is emphasized that both a low rate of generation of endogenous damage and an intrinsically high resistance to modification of tissue macromolecules are key traits of animal longevity.
Energy Technology Data Exchange (ETDEWEB)
Makarov, O., E-mail: makarov@anl.gov [GM/CA-CAT, Biosciences Division, Argonne National Laboratory, Argonne, IL 60439 (United States); Hilgart, M.; Ogata, C.; Pothineni, S. [GM/CA-CAT, Biosciences Division, Argonne National Laboratory, Argonne, IL 60439 (United States); Cork, C. [Physical Biosciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720 (United States)
2011-09-01
GM/CA-CAT at Sector 23 of the Advanced Photon Source (APS) is an NIH funded facility for crystallographic structure determination of biological macromolecules by X-ray diffraction. A second-generation Berkeley automounter is being integrated into the beamline control system at the 23BM experimental station. This new device replaces the previous all-pneumatic gripper motions with a combination of pneumatics and XYZ motorized linear stages. The latter adds a higher degree of flexibility to the robot including auto-alignment capability, accommodation of a larger capacity sample Dewar of arbitrary shape, and support for advanced operations such as crystal washing, while preserving the overall simplicity and efficiency of the Berkeley automounter design.
Introduction to causal dynamical triangulations
DEFF Research Database (Denmark)
Görlich, Andrzej
2013-01-01
The method of causal dynamical triangulations is a non-perturbative and background-independent approach to quantum theory of gravity. In this review we present recent results obtained within the four dimensional model of causal dynamical triangulations. We describe the phase structure of the mode...
Energy Technology Data Exchange (ETDEWEB)
Lindstrom, P
2009-12-23
We describe a simple and efficient algorithm for two-view triangulation of 3D points from approximate 2D matches based on minimizing the L2 reprojection error. Our iterative algorithm improves on the one by Kanatani et al. by ensuring that in each iteration the epipolar constraint is satisfied. In the case where the two cameras are pointed in the same direction, the method provably converges to an optimal solution in exactly two iterations. For more general camera poses, two iterations are sufficient to achieve convergence to machine precision, which we exploit to devise a fast, non-iterative method. The resulting algorithm amounts to little more than solving a quadratic equation, and involves a fixed, small number of simple matrixvector operations and no conditional branches. We demonstrate that the method computes solutions that agree to very high precision with those of Hartley and Sturm's original polynomial method, though achieves higher numerical stability and 1-4 orders of magnitude greater speed.
Macromolecular Prodrugs of Ribavirin
DEFF Research Database (Denmark)
Riber, Camilla Frich; Hinton, Tracey M; Gajda, Paulina
2017-01-01
The requirement for new antiviral therapeutics is an ever present need. Particularly lacking are broad spectrum antivirals that have low toxicity. We develop such agents based on macromolecular prodrugs whereby both the polymer chain and the drug released from the polymer upon cell entry have ant...
Fundamental triangulation networks in Denmark
Directory of Open Access Journals (Sweden)
Borre Kai
2014-04-01
Full Text Available The first triangulation activity on Danish ground was carried out by the astronomer Tycho Brahe who resided on the island Hven. He wanted to determine the longitude difference of his observatory Uraniborg to Copenhagen. A by-product was a map of his island made in 1579. In 1761 the Royal Danish Academy of Sciences and Letters initiated a mapping project which should be based on the principle of triangulation. Eventually 24 maps were printed in varying scales, predominantly in 1:120 000. The last map was engraved in 1842. The Danish GradeMeasurement initiated remeasurements and redesign of the fundamental triangulation network. This network served scientific as well as cartographic purposes in more than a century. Only in the 1960s all triangulation sides were measured electronically. A combined least-squares adjustment followed in the 1970s
Spanning quadrangulations of triangulated surfaces
DEFF Research Database (Denmark)
Kündgen, André; Thomassen, Carsten
2017-01-01
In this paper we study alternating cycles in graphs embedded in a surface. We observe that 4-vertex-colorability of a triangulation on a surface can be expressed in terms of spanninq quadrangulations, and we establish connections between spanning quadrangulations and cycles in the dual graph which...... are noncontractible and alternating with respect to a perfect matching. We show that the dual graph of an Eulerian triangulation of an orientable surface other than the sphere has a perfect matching M and an M-alternating noncontractible cycle. As a consequence, every Eulerian triangulation of the torus has...... a nonbipartite spanning quadrangulation. For an Eulerian triangulation G of the projective plane the situation is different: If the dual graph G∗ is nonbipartite, then G∗ has no noncontractible alternating cycle, and all spanning quadrangulations of G are bipartite. If the dual graph G∗ is bipartite, then it has...
`Optimal' triangulation of surfaces and bodies
Traas, C.R.
1999-01-01
A new criterion is given for constructing an optimal triangulation of surfaces and bodies. The triangulation, called the {\\em tight} triangulation, is convexity preserving and accepts long, thin triangles whenever they are useful. Both properties are not shared by the maxmin triangulation, which in
"Optimal" triangulation of surfaces and bodies
Traas, C.R.
1999-01-01
A new criterion is given for constructing an optimal triangulation of surfaces and bodies. The triangulation, called the {\\em tight} triangulation, is convexity preserving and accepts long, thin triangles whenever they are useful. Both properties are not shared by the maxmin triangulation, which in
Incremental triangulation by way of edge swapping and local optimization
Wiltberger, N. Lyn
1994-01-01
This document is intended to serve as an installation, usage, and basic theory guide for the two dimensional triangulation software 'HARLEY' written for the Silicon Graphics IRIS workstation. This code consists of an incremental triangulation algorithm based on point insertion and local edge swapping. Using this basic strategy, several types of triangulations can be produced depending on user selected options. For example, local edge swapping criteria can be chosen which minimizes the maximum interior angle (a MinMax triangulation) or which maximizes the minimum interior angle (a MaxMin or Delaunay triangulation). It should be noted that the MinMax triangulation is generally only locally optical (not globally optimal) in this measure. The MaxMin triangulation, however, is both locally and globally optical. In addition, Steiner triangulations can be constructed by inserting new sites at triangle circumcenters followed by edge swapping based on the MaxMin criteria. Incremental insertion of sites also provides flexibility in choosing cell refinement criteria. A dynamic heap structure has been implemented in the code so that once a refinement measure is specified (i.e., maximum aspect ratio or some measure of a solution gradient for the solution adaptive grid generation) the cell with the largest value of this measure is continually removed from the top of the heap and refined. The heap refinement strategy allows the user to specify either the number of cells desired or refine the mesh until all cell refinement measures satisfy a user specified tolerance level. Since the dynamic heap structure is constantly updated, the algorithm always refines the particular cell in the mesh with the largest refinement criteria value. The code allows the user to: triangulate a cloud of prespecified points (sites), triangulate a set of prespecified interior points constrained by prespecified boundary curve(s), Steiner triangulate the interior/exterior of prespecified boundary curve
Issues in using methodological triangulation in research.
Casey, Dympna; Murphy, Kathy
2009-01-01
This paper describes how methodological triangulation was used in two nursing research studies. The literature identified a number of principles in reporting studies that used triangulation, including giving the rationale for using triangulation, detailing the process used to assist with triangulation and explaining how rigour was maintained. A brief review of triangulated studies revealed that few adhered fully to these principles. A 'within method' and an 'across method' study are used to illustrate how methodological triangulation was used, and the ways in which rigour was addressed are also described. In addition, the different contributions of triangulation to nursing research are highlighted.
Macromolecular Crystallization in Microgravity
Snell, Edward H.; Helliwell, John R.
2004-01-01
The key concepts that attracted crystal growers, macromolecular or solid state, to microgravity research is that density difference fluid flows and sedimentation of the growing crystals are greatly reduced. Thus, defects and flaws in the crystals can be reduced, even eliminated, and crystal volume can be increased. Macromolecular crystallography differs from the field of crystalline semiconductors. For the latter, crystals are harnessed for their electrical behaviors. A crystal of a biological macromolecule is used instead for diffraction experiments (X-ray or neutron) to determine the three-dimensional structure of the macromolecule. The better the internal order of the crystal of a biological macromolecule then the more molecular structure detail that can be extracted. This structural information that enables an understanding of how the molecule functions. This knowledge is changing the biological and chemical sciences with major potential in understanding disease pathologies. Macromolecular structural crystallography in general is a remarkable field where physics, biology, chemistry, and mathematics meet to enable insight to the basic fundamentals of life. In this review, we examine the use of microgravity as an environment to grow macromolecular crystals. We describe the crystallization procedures used on the ground, how the resulting crystals are studied and the knowledge obtained from those crystals. We address the features desired in an ordered crystal and the techniques used to evaluate those features in detail. We then introduce the microgravity environment, the techniques to access that environment, and the theory and evidence behind the use of microgravity for crystallization experiments. We describe how ground-based laboratory techniques have been adapted to microgravity flights and look at some of the methods used to analyze the resulting data. Several case studies illustrate the physical crystal quality improvements and the macromolecular structural
Coefficient adaptive triangulation for strongly anisotropic problems
Energy Technology Data Exchange (ETDEWEB)
D`Azevedo, E.F.; Romine, C.H.; Donato, J.M.
1996-01-01
Second order elliptic partial differential equations arise in many important applications, including flow through porous media, heat conduction, the distribution of electrical or magnetic potential. The prototype is the Laplace problem, which in discrete form produces a coefficient matrix that is relatively easy to solve in a regular domain. However, the presence of anisotropy produces a matrix whose condition number is increased, making the resulting linear system more difficult to solve. In this work, we take the anisotropy into account in the discretization by mapping each anisotropic region into a ``stretched`` coordinate space in which the anisotropy is removed. The region is then uniformly triangulated, and the resulting triangulation mapped back to the original space. The effect is to generate long slender triangles that are oriented in the direction of ``preferred flow.`` Slender triangles are generally regarded as numerically undesirable since they tend to cause poor conditioning; however, our triangulation has the effect of producing effective isotropy, thus improving the condition number of the resulting coefficient matrix.
Institute of Scientific and Technical Information of China (English)
杨小运; 陈和平; 顾进广; 杨剑
2012-01-01
In the study of the existing algorithms of constrained Delaunay triangulation. To the disadvantages of low efficiency of locating points and complexity of searching influence area in the traditional synthesis algorithms, two improvements in the algorithms are presented: First, quickly locating the triangle which the insertion point in; Next, optimizing the process of searching of the influence domain. Effectively reduce the time of the searching process of the point and the influence domain of the constitute grid. And the simulation experiments are finished respectively using the traditional synthesis algorithm and the improved algorithm combined with the finite element algorithm in the "blast furnace lining erosion curve prediction" project The results show that this algorithm is more stable and more efficiency.%在研究现有约束Delaunay三角网生成算法后,针对传统合成算法中点定位过程效率低,搜索影响域算法复杂的缺点,对合成算法进行了两点改进:一是快速定位点所在的三角形；二是优化搜索影响域的算法.改进后的算法有效的缩短了构网过程中定位点和搜索影响域的时间,提高了构网效率.分别利用传统合成算法与改进后的算法结合有限元算法在高炉炉衬侵蚀曲线预测工程项目中进行了分组仿真实验.实验数据表明,改进后的算法更加稳定,剖分效率更高.
A TQFT of Tuarev-Viro type on shaped triangulations
Energy Technology Data Exchange (ETDEWEB)
Kashaev, Rinat [Geneva Univ. (Switzerland); Luo, Feng [Rutgers Univ., Piscataway, NJ (United States). Dept. of Mathematics; Vartanov, Grigory [Deutsches Elektronen-Synchrotron (DESY), Hamburg (Germany)
2012-10-15
A shaped triangulation is a finite triangulation of an oriented pseudo three manifold where each tetrahedron carries dihedral angles of an ideal hyberbolic tetrahedron. To each shaped triangulation, we associate a quantum partition function in the form of an absolutely convergent state integral which is invariant under shaped 3-2 Pachner moves and invariant with respect to shape gauge transformations generated by total dihedral angles around internal edges through the Neumann-Zagier Poisson bracket. Similarly to Turaev-Viro theory, the state variables live on edges of the triangulation but take their values on the whole real axis. The tetrahedral weight functions are composed of three hyperbolic gamma functions in a way that they enjoy a manifest tetrahedral symmetry. We conjecture that for shaped triangulations of closed 3-manifolds, our partition function is twice the absolute value squared of the partition function of Techmueller TQFT defined by Andersen and Kashaev. This is similar to the known relationship between the Turaev-Viro and the Witten-Reshetikhin-Turaev invariants of three manifolds. We also discuss interpretations of our construction in terms of three-dimensional supersymmetric field theories related to triangulated three-dimensional manifolds.
Quasi-greedy triangulations approximating the minimum weight triangulation
Energy Technology Data Exchange (ETDEWEB)
Levcopoulos, C.; Krznaric, D. [Lund Univ. (Sweden)
1996-12-31
This paper settles the following two open problems: (1) What is the worst-case approximation ratio between the greedy and the minimum weight triangulation? (2) Is there a polynomial time algorithm that always pro- duces a triangulation whose length is within a constant factor from the minimum? The answer to the first question is that the known {Omega}({radical}n) lower bound is tight. The second question is answered in the affirmative by using a slight modification of an O(n log n) algorithm for the greedy triangulation. We also derive some other interesting results. For example, we show that a constant-factor approximation of the minimum weight convex partition can be obtained within the same time bounds.
Macromolecular crystallization in microgravity
Energy Technology Data Exchange (ETDEWEB)
Snell, Edward H [Biophysics Group, NASA Marshall Space Flight Center, Code XD42, Huntsville, AL 35812 (United States); Helliwell, John R [Department of Chemistry, The University of Manchester, Manchester, M13 9PL (United Kingdom)
2005-04-01
Density difference fluid flows and sedimentation of growing crystals are greatly reduced when crystallization takes place in a reduced gravity environment. In the case of macromolecular crystallography a crystal of a biological macromolecule is used for diffraction experiments (x-ray or neutron) so as to determine the three-dimensional structure of the macromolecule. The better the internal order of the crystal then the greater the molecular structure detail that can be extracted. It is this structural information that enables an understanding of how the molecule functions. This knowledge is changing the biological and chemical sciences, with major potential in understanding disease pathologies. In this review, we examine the use of microgravity as an environment to grow macromolecular crystals. We describe the crystallization procedures used on the ground, how the resulting crystals are studied and the knowledge obtained from those crystals. We address the features desired in an ordered crystal and the techniques used to evaluate those features in detail. We then introduce the microgravity environment, the techniques to access that environment and the theory and evidence behind the use of microgravity for crystallization experiments. We describe how ground-based laboratory techniques have been adapted to microgravity flights and look at some of the methods used to analyse the resulting data. Several case studies illustrate the physical crystal quality improvements and the macromolecular structural advances. Finally, limitations and alternatives to microgravity and future directions for this research are covered. Macromolecular structural crystallography in general is a remarkable field where physics, biology, chemistry and mathematics meet to enable insight to the fundamentals of life. As the reader will see, there is a great deal of physics involved when the microgravity environment is applied to crystallization, some of it known, and undoubtedly much yet to
Fat Triangulations and Differential Geometry
Saucan, Emil
2011-01-01
We study the differential geometric consequences of our previous result on the existence of fat triangulations, in conjunction with a result of Cheeger, M\\"{u}ller and Schrader, regarding the convergence of Lipschitz-Killing curvatures of piecewise-flat approximations of smooth Riemannian manifolds. A further application to the existence of quasiconformal mappings between manifolds, as well as an extension of the triangulation result to the case of almost Riemannian manifolds, are also given. In addition, the notion of fatness of triangulations and its relation to metric curvature and to excess is explored. Moreover, applications of the main results, and in particular a purely metric approach to Regge calculus, are also investigated.
The Construction of Sorkin Triangulations
Tuckey, P A
1993-01-01
Some time ago, Sorkin (1975) reported investigations of the time evolution and initial value problems in Regge calculus, for one triangulation each of the manifolds $R*S^3$ and $R^4$. Here we display the simple, local characteristic of those triangulations which underlies the structure found by Sorkin, and emphasise its general applicability, and therefore the general validity of Sorkin's conclusions. We also make some elementary observations on the resulting structure of the time evolution and initial value problems in Regge calculus, and add some comments and speculations.
Strategies for nonobtuse boundary Delaunay triangulations
Energy Technology Data Exchange (ETDEWEB)
Murphy, M. [Univ. of Maryland, College Park, MD (United States). Dept. of Computer Science]|[Los Alamos National Lab., NM (United States); Gable, C.W. [Los Alamos National Lab., NM (United States). Earth and Environmental Science Div.
1998-12-31
Delaunay Triangulations with nonobtuse triangles at the boundaries satisfy a minimal requirement for Control Volume meshes. They motivate this quality requirement, discuss it in context with others that have been proposed, and give point placement strategies that generate the fewest or close to the fewest number of Steiner points needed to satisfy it for a particular problem instance. The advantage is that this strategy places a number of Steiner points proportional to the combinatorial size of the input rather than the local feature size, resulting in far fewer points in many cases.
Triangulation of cubic panorama for view synthesis.
Zhang, Chunxiao; Zhao, Yan; Wu, Falin
2011-08-01
An unstructured triangulation approach, new to our knowledge, is proposed to apply triangular meshes for representing and rendering a scene on a cubic panorama (CP). It sophisticatedly converts a complicated three-dimensional triangulation into a simple three-step triangulation. First, a two-dimensional Delaunay triangulation is individually carried out on each face. Second, an improved polygonal triangulation is implemented in the intermediate regions of each of two faces. Third, a cobweblike triangulation is designed for the remaining intermediate regions after unfolding four faces to the top/bottom face. Since the last two steps well solve the boundary problem arising from cube edges, the triangulation with irregular-distribution feature points is implemented in a CP as a whole. The triangular meshes can be warped from multiple reference CPs onto an arbitrary viewpoint by face-to-face homography transformations. The experiments indicate that the proposed triangulation approach provides a good modeling for the scene with photorealistic rendered CPs.
Microgravity and Macromolecular Crystallography
Kundrot, Craig E.; Judge, Russell A.; Pusey, Marc L.; Snell, Edward H.; Rose, M. Franklin (Technical Monitor)
2000-01-01
Macromolecular crystal growth has been seen as an ideal experiment to make use of the reduced acceleration environment provided by an orbiting spacecraft. The experiments are small, simply operated and have a high potential scientific and economic impact. In this review we examine the theoretical reasons why microgravity should be a beneficial environment for crystal growth and survey the history of experiments on the Space Shuttle Orbiter, on unmanned spacecraft, and on the Mir space station. Finally we outline the direction for optimizing the future use of orbiting platforms.
Sequential triangulation of orbital photography
Rajan, M.; Junkins, J. L.; Turner, J. D.
1979-01-01
The feasibility of structuring the satellite photogrammetric triangulation as an iterative Extended Kalman estimation algorithm is demonstrated. Comparative numerical results of the sequential against batch estimation algorithm are presented. Difficulty of accurately modeling of the attitude motion is overcome by utilizing the on-board angular rate measurements. Solutions of the differential equations and the evaluation of state transition matrix are carried out numerically.
Fundamental triangulation networks in Denmark
DEFF Research Database (Denmark)
Borre, Kai
2014-01-01
Academy of Sciences and Letters initiated a mapping project which should be based on the principle of triangulation. Eventually 24 maps were printed in varying scales, predominantly in 1:120 000. The last map was engraved in 1842. The Danish GradeMeasurement initiated remeasurements and redesign...
Sequential triangulation of orbital photography
Rajan, M.; Junkins, J. L.; Turner, J. D.
1979-01-01
The feasibility of structuring the satellite photogrammetric triangulation as an iterative Extended Kalman estimation algorithm is demonstrated. Comparative numerical results of the sequential against batch estimation algorithm are presented. Difficulty of accurately modeling of the attitude motion is overcome by utilizing the on-board angular rate measurements. Solutions of the differential equations and the evaluation of state transition matrix are carried out numerically.
An efficient advancing front algorithm for Delaunay triangulation
Merriam, Marshal L.
1991-01-01
There has been some recent interest in fluid dynamics calculations on unstructured meshes. One method of unstructured mesh generation involves Delaunay triangulation. This method has certain advantages but it can be expensive to implement. Furthermore, there can be problems with crossing grid lines near boundaries. A method shown here avoids many of the robustness and efficiency problems previously associated with Delaunay triangulation. As an added feature, a simple algorithm is shown which allows removal of diagonal edges from cells that are nearly rectangular. This can result in significant savings in the cost per iteration of a flow solver using this grid.
An efficient advancing front algorithm for Delaunay triangulation
Merriam, Marshal L.
1991-01-01
There has been some recent interest in fluid dynamics calculations on unstructured meshes. One method of unstructured mesh generation involves Delaunay triangulation. This method has certain advantages but it can be expensive to implement. Furthermore, there can be problems with crossing grid lines near boundaries. A method shown here avoids many of the robustness and efficiency problems previously associated with Delaunay triangulation. As an added feature, a simple algorithm is shown which allows removal of diagonal edges from cells that are nearly rectangular. This can result in significant savings in the cost per iteration of a flow solver using this grid.
Multi-Sensor Triangulation of Multi-Source Spatial Data
Habib, Ayman; Kim, Chang-Jae; Bang, Ki-In
2007-01-01
The introduced methodologies are successful in: a) Ising LIDAR features for photogrammetric geo-refererncing; b) Delivering a geo-referenced imagery of the same quality as point-based geo-referencing procedures; c) Taking advantage of the synergistic characteristics of spatial data acquisition systems. The triangulation output can be used for the generation of 3-D perspective views.
Phenomenology of Causal Dynamical Triangulations
Mielczarek, Jakub
2015-01-01
The four dimensional Causal Dynamical Triangulations (CDT) approach to quantum gravity is already more than ten years old theory with numerous unprecedented predictions such as non-trivial phase structure of gravitational field and dimensional running. Here, we discuss possible empirical consequences of CDT derived based on the two features of the approach mentioned above. A possibility of using both astrophysical and cosmological observations to test CDT is discussed. We show that scenarios which can be ruled out at the empirical level exist.
Volumes of Polytopes Without Triangulations
Enciso, Michael
2014-01-01
We introduce a new formalism for defining and computing the volumes of completely general polytopes in any dimension. The expressions that we obtain for these volumes are independent of any triangulation, and manifestly depend only on the vertices of the underlying polytope. As one application of this formalism, we obtain new expressions for tree-level, n-point NMHV amplitudes in N=4 Super Yang-Mills (SYM) theory.
Institute of Scientific and Technical Information of China (English)
王明海; 耿迅; 张军; 戈一鸣
2012-01-01
Traditional film aerial photogrammetry cameras are gradually replaced by digital cameras. ADS40 is the representative pushbroom digital camera which integrates GPS/IMU system. ADS40 can acquire multi-bandand multi-angle digital images simultaneously. In this paper,a method of quickly generating orthophoto from ADS40 images is introduced. In view of that GPS/IMU system can produce high accuracy position and orientation data, we directly use exterior elements and automatic extracted DEM to rectify raw images. Because of data processing without aerial triangulation and without GCP measured, we can save a lot of time. The experimental results show that the generated orthophoto can satisfy the accuracy requirement of mapping standard with mush less processing time. It is especially fit for rapid response surveying and mapping.%介绍了ADS40相机快速生成正射影像图的方法,即利用高精度POS设备能直接定向测图的特点,省去空三工序,利用POS解算出的外方位元素和自动提取的DEM进行正射影像纠正,结合实际生产项目对成图精度进行了分析.试验结果表明,ADS40相机应用于航测生产可大幅度缩短成图周期,利用本文的生产方法可以满足正射影像图精度要求,并节省大量时间,适用于应急测绘保障.
Triangulation of Data Analysis Techniques
Directory of Open Access Journals (Sweden)
Lauri, M
2011-10-01
Full Text Available In psychology, as in other disciplines, the concepts of validity and reliability are considered essential to give an accurate interpretation of results. While in quantitative research the idea is well established, in qualitative research, validity and reliability take on a different dimension. Researchers like Miles and Huberman (1994 and Silverman (2000, 2001, have shown how these issues are addressed in qualitative research. In this paper I am proposing that the same corpus of data, in this case the transcripts of focus group discussions, can be analysed using more than one data analysis technique. I refer to this idea as ‘triangulation of data analysis techniques’ and argue that such triangulation increases the reliability of the results. If the results obtained through a particular data analysis technique, for example thematic analysis, are congruent with the results obtained by analysing the same transcripts using a different technique, for example correspondence analysis, it is reasonable to argue that the analysis and interpretation of the data is valid.
Mixed Methods, Triangulation, and Causal Explanation
Howe, Kenneth R.
2012-01-01
This article distinguishes a disjunctive conception of mixed methods/triangulation, which brings different methods to bear on different questions, from a conjunctive conception, which brings different methods to bear on the same question. It then examines a more inclusive, holistic conception of mixed methods/triangulation that accommodates…
Mixed Methods, Triangulation, and Causal Explanation
Howe, Kenneth R.
2012-01-01
This article distinguishes a disjunctive conception of mixed methods/triangulation, which brings different methods to bear on different questions, from a conjunctive conception, which brings different methods to bear on the same question. It then examines a more inclusive, holistic conception of mixed methods/triangulation that accommodates…
Simulating triangulations. Graphs, manifolds and (quantum) spacetime
Energy Technology Data Exchange (ETDEWEB)
Krueger, Benedikt
2016-07-01
Triangulations, which can intuitively be described as a tessellation of space into simplicial building blocks, are structures that arise in various different branches of physics: They can be used for describing complicated and curved objects in a discretized way, e.g., in foams, gels or porous media, or for discretizing curved boundaries for fluid simulations or dissipative systems. Interpreting triangulations as (maximal planar) graphs makes it possible to use them in graph theory or statistical physics, e.g., as small-world networks, as networks of spins or in biological physics as actin networks. Since one can find an analogue of the Einstein-Hilbert action on triangulations, they can even be used for formulating theories of quantum gravity. Triangulations have also important applications in mathematics, especially in discrete topology. Despite their wide occurrence in different branches of physics and mathematics, there are still some fundamental open questions about triangulations in general. It is a prior unknown how many triangulations there are for a given set of points or a given manifold, or even whether there are exponentially many triangulations or more, a question that relates to a well-defined behavior of certain quantum geometry models. Another major unknown question is whether elementary steps transforming triangulations into each other, which are used in computer simulations, are ergodic. Using triangulations as model for spacetime, it is not clear whether there is a meaningful continuum limit that can be identified with the usual and well-tested theory of general relativity. Within this thesis some of these fundamental questions about triangulations are answered by the use of Markov chain Monte Carlo simulations, which are a probabilistic method for calculating statistical expectation values, or more generally a tool for calculating high-dimensional integrals. Additionally, some details about the Wang-Landau algorithm, which is the primary used
Interferometer predictions with triangulated images
DEFF Research Database (Denmark)
Brinch, Christian; Dullemond, C. P.
2014-01-01
Interferometers play an increasingly important role for spatially resolved observations. If employed at full potential, interferometry can probe an enormous dynamic range in spatial scale. Interpretation of the observed visibilities requires the numerical computation of Fourier integrals over...... the synthetic model images. To get the correct values of these integrals, the model images must have the right size and resolution. Insufficient care in these choices can lead to wrong results. We present a new general-purpose scheme for the computation of visibilities of radiative transfer images. Our method...... requires a model image that is a list of intensities at arbitrarily placed positions on the image-plane. It creates a triangulated grid from these vertices, and assumes that the intensity inside each triangle of the grid is a linear function. The Fourier integral over each triangle is then evaluated...
On deformations of triangulated models
De Deken, Olivier
2012-01-01
This paper is the first part of a project aimed at understanding deformations of triangulated categories, and more precisely their dg and A infinity models, and applying the resulting theory to the models occurring in the Homological Mirror Symmetry setup. In this first paper, we focus on models of derived and related categories, based upon the classical construction of twisted objects over a dg or $A_{\\infty}$-algebra. For a Hochschild 2 cocycle on such a model, we describe a corresponding "curvature compensating" deformation which can be entirely understood within the framework of twisted objects. We unravel the construction in the specific cases of derived A infinity and abelian categories, homotopy categories, and categories of graded free qdg-modules. We identify a purity condition on our models which ensures that the structure of the model is preserved under deformation. This condition is typically fulfilled for homotopy categories, but not for unbounded derived categories.
Grounded theory, feminist theory, critical theory: toward theoretical triangulation.
Kushner, Kaysi Eastlick; Morrow, Raymond
2003-01-01
Nursing and social science scholars have examined the compatibility between feminist and grounded theory traditions in scientific knowledge generation, concluding that they are complementary, yet not without certain tensions. This line of inquiry is extended to propose a critical feminist grounded theory methodology. The construction of symbolic interactionist, feminist, and critical feminist variants of grounded theory methodology is examined in terms of the presuppositions of each tradition and their interplay as a process of theoretical triangulation.
Methodological triangulation: an approach to understanding data.
Bekhet, Abir K; Zauszniewski, Jaclene A
2012-01-01
To describe the use of methodological triangulation in a study of how people who had moved to retirement communities were adjusting. Methodological triangulation involves using more than one kind of method to study a phenomenon. It has been found to be beneficial in providing confirmation of findings, more comprehensive data, increased validity and enhanced understanding of studied phenomena. While many researchers have used this well-established technique, there are few published examples of its use. The authors used methodological triangulation in their study of people who had moved to retirement communities in Ohio, US. A blended qualitative and quantitative approach was used. The collected qualitative data complemented and clarified the quantitative findings by helping to identify common themes. Qualitative data also helped in understanding interventions for promoting 'pulling' factors and for overcoming 'pushing' factors of participants. The authors used focused research questions to reflect the research's purpose and four evaluative criteria--'truth value', 'applicability', 'consistency' and 'neutrality'--to ensure rigour. This paper provides an example of how methodological triangulation can be used in nursing research. It identifies challenges associated with methodological triangulation, recommends strategies for overcoming them, provides a rationale for using triangulation and explains how to maintain rigour. Methodological triangulation can be used to enhance the analysis and the interpretation of findings. As data are drawn from multiple sources, it broadens the researcher's insight into the different issues underlying the phenomena being studied.
Willsch, Michael; Villnow, Michael; Bosselmann, Thomas
2015-09-01
Commercial distance sensors basing on the triangulation principle are highly accurate and reliable. However due to their contained electronics and optoelectronics they cannot be used in harsh environments such as high temperatures and strong electromagnetic fields. An all fiber optical triangulation sensor principle is presented here which can be used for tip clearance measurements of rotors of large engines such as power generators and turbines.
Multiscale macromolecular simulation: role of evolving ensembles.
Singharoy, A; Joshi, H; Ortoleva, P J
2012-10-22
Multiscale analysis provides an algorithm for the efficient simulation of macromolecular assemblies. This algorithm involves the coevolution of a quasiequilibrium probability density of atomic configurations and the Langevin dynamics of spatial coarse-grained variables denoted order parameters (OPs) characterizing nanoscale system features. In practice, implementation of the probability density involves the generation of constant OP ensembles of atomic configurations. Such ensembles are used to construct thermal forces and diffusion factors that mediate the stochastic OP dynamics. Generation of all-atom ensembles at every Langevin time step is computationally expensive. Here, multiscale computation for macromolecular systems is made more efficient by a method that self-consistently folds in ensembles of all-atom configurations constructed in an earlier step, history, of the Langevin evolution. This procedure accounts for the temporal evolution of these ensembles, accurately providing thermal forces and diffusions. It is shown that efficiency and accuracy of the OP-based simulations is increased via the integration of this historical information. Accuracy improves with the square root of the number of historical timesteps included in the calculation. As a result, CPU usage can be decreased by a factor of 3-8 without loss of accuracy. The algorithm is implemented into our existing force-field based multiscale simulation platform and demonstrated via the structural dynamics of viral capsomers.
RESEARCH ON ADAPTIVE DATA COMPRESSION METHOD FOR TRIANGULATED SURFACES
Institute of Scientific and Technical Information of China (English)
Wang Wen; Wu Shixiong; Chen Zichen
2004-01-01
NC code or STL file can be generated directly from measuring data in a fast reverse-engineering mode.Compressing the massive data from laser scanner is the key of the new mode.An adaptive compression method based on triangulated-surfaces model is put forward.Normal-vector angles between triangles are computed to find prime vertices for removal.Ring data structure is adopted to save massive data effectively.It allows the efficient retrieval of all neighboring vertices and triangles of a given vertices.To avoid long and thin triangles,a new re-triangulation approach based on normalized minimum-vertex-distance is proposed,in which the vertex distance and interior angle of triangle are considered.Results indicate that the compression method has high efficiency and can get reliable precision.The method can be applied in fast reverse engineering to acquire an optimal subset of the original massive data.
Personal authentication using hand vein triangulation and knuckle shape.
Kumar, Ajay; Prathyusha, K Venkata
2009-09-01
This paper presents a new approach to authenticate individuals using triangulation of hand vein images and simultaneous extraction of knuckle shape information. The proposed method is fully automated and employs palm dorsal hand vein images acquired from the low-cost, near infrared, contactless imaging. The knuckle tips are used as key points for the image normalization and extraction of region of interest. The matching scores are generated in two parallel stages: (i) hierarchical matching score from the four topologies of triangulation in the binarized vein structures and (ii) from the geometrical features consisting of knuckle point perimeter distances in the acquired images. The weighted score level combination from these two matching scores are used to authenticate the individuals. The achieved experimental results from the proposed system using contactless palm dorsal-hand vein images are promising (equal error rate of 1.14%) and suggest more user friendly alternative for user identification.
Makarov, O; Hilgart, M; Ogata, C; Pothineni, S; Cork, C
2011-09-01
GM/CA CAT at Sector 23 of the Advanced Photon Source (APS) is an NIH funded facility for crystallographic structure determination of biological macromolecules by X-ray diffraction.A second generation Berkeley automounter is being integrated into the beamline control system at the 23-BM experimental station. This new device replaces the previous all-pneumatic gripper motions with a combination of pneumatics and XYZ motorized linear stages. The latter adds a higher degree of flexibility to the robot including auto-alignment capability, accommodation of a larger capacity sample Dewar of arbitrary shape, and support for advanced operations such as crystal washing, while preserving the overall simplicity and efficiency of the Berkeley automounter design.
Celebrating macromolecular crystallography: A personal perspective
Directory of Open Access Journals (Sweden)
Abad-Zapatero, Celerino
2015-04-01
Full Text Available The twentieth century has seen an enormous advance in the knowledge of the atomic structures that surround us. The discovery of the first crystal structures of simple inorganic salts by the Braggs in 1914, using the diffraction of X-rays by crystals, provided the critical elements to unveil the atomic structure of matter. Subsequent developments in the field leading to macromolecular crystallography are presented with a personal perspective, related to the cultural milieu of Spain in the late 1950’s. The journey of discovery of the author, as he developed professionally, is interwoven with the expansion of macromolecular crystallography from the first proteins (myoglobin, hemoglobin to the ‘coming of age’ of the field in 1971 and the discoveries that followed, culminating in the determination of the structure of the ribosomes at the turn of the century. A perspective is presented exploring the future of the field and also a reflection about the future generations of Spanish scientists.El siglo XX ha sido testigo del increíble avance que ha experimentado el conocimiento de la estructura atómica de la materia que nos rodea. El descubrimiento de las primeras estructuras atómicas de sales inorgánicas por los Bragg en 1914, empleando difracción de rayos X con cristales, proporcionó los elementos clave para alcanzar tal conocimiento. Posteriores desarrollos en este campo, que condujeron a la cristalografía macromolecular, se presentan aquí desde una perspectiva personal, relacionada con el contexto cultural de la España de la década de los 50. La experiencia del descubrimiento científico, durante mi desarrollo profesional, se integra en el desarrollo de la cristalografía macromolecular, desde las primeras proteínas (míoglobina y hemoglobina, hasta su madurez en 1971 que, con los posteriores descubrimientos, culmina con la determinación del la estructura del ribosoma. Asimismo, se explora el futuro de esta disciplina y se
Reconstructing surface triangulations by their intersection matrices
2014-01-01
The intersection matrix of a finite simplicial complex has as each of its entries the rank of the intersection of its respective simplices. We prove that such matrix defines the triangulation of a closed connected surface up to isomorphism.
Constrained Delaunay Triangulation for Ad Hoc Networks
Directory of Open Access Journals (Sweden)
D. Satyanarayana
2008-01-01
Full Text Available Geometric spanners can be used for efficient routing in wireless ad hoc networks. Computation of existing spanners for ad hoc networks primarily focused on geometric properties without considering network requirements. In this paper, we propose a new spanner called constrained Delaunay triangulation (CDT which considers both geometric properties and network requirements. The CDT is formed by introducing a small set of constraint edges into local Delaunay triangulation (LDel to reduce the number of hops between nodes in the network graph. We have simulated the CDT using network simulator (ns-2.28 and compared with Gabriel graph (GG, relative neighborhood graph (RNG, local Delaunay triangulation (LDel, and planarized local Delaunay triangulation (PLDel. The simulation results show that the minimum number of hops from source to destination is less than other spanners. We also observed the decrease in delay, jitter, and improvement in throughput.
Formal study of plane Delaunay triangulation
Dufourd, Jean-François
2010-01-01
This article presents the formal proof of correctness for a plane Delaunay triangulation algorithm. It consists in repeating a sequence of edge flippings from an initial triangulation until the Delaunay property is achieved. To describe triangulations, we rely on a combinatorial hypermap specification framework we have been developing for years. We embed hypermaps in the plane by attaching coordinates to elements in a consistent way. We then describe what are legal and illegal Delaunay edges and a flipping operation which we show preserves hypermap, triangulation, and embedding invariants. To prove the termination of the algorithm, we use a generic approach expressing that any non-cyclic relation is well-founded when working on a finite set.
Locally Causal Dynamical Triangulations in Two Dimensions
Loll, Renate
2015-01-01
We analyze the universal properties of a new two-dimensional quantum gravity model defined in terms of Locally Causal Dynamical Triangulations (LCDT). Measuring the Hausdorff and spectral dimensions of the dynamical geometrical ensemble, we find numerical evidence that the continuum limit of the model lies in a new universality class of two-dimensional quantum gravity theories, inequivalent to both Euclidean and Causal Dynamical Triangulations.
TRIANGULATION OF METHODS OF CAREER EDUCATION
Marija Turnsek Mikacic
2015-01-01
This paper is an overview of the current research in the field of career education and career planning. Presented results constitute a model based on the insight into different theories and empirical studies about career planning as a building block of personal excellence. We defined credibility, transferability and reliability of the research by means of triangulation. As sources of data of triangulation we included essays of participants of education and questionnaires. Qualitative analysi...
Surface Triangulation for CSG in Mercury
Energy Technology Data Exchange (ETDEWEB)
Engel, Daniel [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Georgia Inst. of Technology, Atlanta, GA (United States); O' Brien, Matthew J. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)
2015-08-26
Visualization routines for rendering complicated geometries are very useful for engineers and scientists who are trying to build 3D prototypes of their designs. A common way to rapidly add interesting features to a 3D model is through the use of a concept called Constructive Solid Geometry. CSG uses compositions of the boolean set operations to manipulate basic geometric primitives to form more complicated objects. The most common boolean operations employed are union, intersection, and subtraction. Most computer-aided design software packages contain some sort of ability visualize CSG. The typical workflow for the user is as follows: The user specifies the individual primitive components, the user arbitrarily combines each of these primitives with boolean operations, the software generates a CSG tree structure which normally stores these solids implicitly with their defining equation, the tree is traversed and a general algorithm is applied to render the appropriate geometry onto the screen. Algorithms for visualizing CSG have been extensively developed for over a decade. Points sampled from the implicit solids are typically used as input by variations of algorithms like marching cubes and point-cloud surface reconstruction. Here, we explain a surface triangulation method from the graphics community that is being used for surface visualization in the framework of a Monte-Carlo neutron transport code called Mercury.
Löffler, Maarten
2012-01-01
We show that Delaunay triangulations and compressed quadtrees are equivalent structures. More precisely, we give two algorithms: the first computes a compressed quadtree for a planar point set, given the Delaunay triangulation; the second finds the Delaunay triangulation, given a compressed quadtree. Both algorithms run in deterministic linear time on a pointer machine. Our work builds on and extends previous results by Krznaric and Levcopolous and Buchin and Mulzer. Our main tool for the second algorithm is the well-separated pair decomposition(WSPD), a structure that has been used previously to find Euclidean minimum spanning trees in higher dimensions (Eppstein). We show that knowing the WSPD (and a quadtree) suffices to compute a planar Euclidean minimum spanning tree (EMST) in linear time. With the EMST at hand, we can find the Delaunay triangulation in linear time. As a corollary, we obtain deterministic versions of many previous algorithms related to Delaunay triangulations, such as splitting planar De...
Macromolecular architectures for organic photovoltaics.
Popere, Bhooshan C; Della Pelle, Andrea M; Poe, Ambata; Thayumanavan, S
2012-03-28
Research in the field of organic photovoltaics has gained considerable momentum in the last two decades owing to the need for developing low-cost and efficient energy harvesting systems. Elegant molecular architectures have been designed, synthesized and employed as active materials for photovoltaic devices thereby leading to a better molecular structure-device property relationship understanding. In this perspective, we outline new macromolecular scaffolds that have been designed within the purview of each of the three fundamental processes involving light harvesting, charge separation and charge transport.
Emergent Property in Macromolecular Motion
Institute of Scientific and Technical Information of China (English)
吴嘉麟
2003-01-01
In this paper, the model of inverse cascade fractal super-blocks along one direction (in the positive or negative) in the 3-dimensional space is developed to describe the self-similar motion in macromolecular system. Microscopically the cohesive and dispersed states of the motion blocks are co-existent states with vastly different probability of occurrence.Experimental results and theoretical analysis show that the microscopic cohesive state energy and dispersed state energy of each motion block are respectively equal to the macroscopic glassy state energy kT8 and molten state energy kTm of the system. This singularity unveils topologically the nonintegrability, mathematically the anholonomy, and macroscopically the emergent property. This singularity also reveals that the glass, viscoelastic and melt states are three distinct emergent properties of macromolecular motion from a macroscopic viewpoint. The fractal concept of excluded volume is introduced to depict the random motion at various scales in the system. The Hausdorff dimensions of the excluded volune and the motion blocks are both found equal to 3/2.
Data Mining of Macromolecular Structures.
van Beusekom, Bart; Perrakis, Anastassis; Joosten, Robbie P
2016-01-01
The use of macromolecular structures is widespread for a variety of applications, from teaching protein structure principles all the way to ligand optimization in drug development. Applying data mining techniques on these experimentally determined structures requires a highly uniform, standardized structural data source. The Protein Data Bank (PDB) has evolved over the years toward becoming the standard resource for macromolecular structures. However, the process selecting the data most suitable for specific applications is still very much based on personal preferences and understanding of the experimental techniques used to obtain these models. In this chapter, we will first explain the challenges with data standardization, annotation, and uniformity in the PDB entries determined by X-ray crystallography. We then discuss the specific effect that crystallographic data quality and model optimization methods have on structural models and how validation tools can be used to make informed choices. We also discuss specific advantages of using the PDB_REDO databank as a resource for structural data. Finally, we will provide guidelines on how to select the most suitable protein structure models for detailed analysis and how to select a set of structure models suitable for data mining.
Macromolecular mimicry of nucleic acid and protein
DEFF Research Database (Denmark)
Nautrup Pedersen, Gitte; Nyborg, Jens; Clark, Brian F
1999-01-01
of the concept of macromolecular mimicry. Macromolecular mimicry has further been proposed among initiation and release factors, thereby adding a new element to the description of protein synthesis in bacteria. Such mimicry has also been observed in other biological processes such as autoimmunity, DNA repair......, and gene regulation, at both transcriptional and translational levels. Udgivelsesdato: 1999-Jul...
COUNTING FAIR NEAR-TRIANGULATIONS ON THE DISC
Institute of Scientific and Technical Information of China (English)
无
2000-01-01
In this paper various kinds of fair near-triangulations are enumerated and several other types of near-triangulations are counted with the root-face valency,the number of edges and faces as the parameters.
Liver-targeting macromolecular MRI contrast agents
Institute of Scientific and Technical Information of China (English)
无
2001-01-01
Macromolecular ligands with liver-targeting group (pyridoxamine, PM) PHEA-DTPA-PM and PAEA-DTPA-PM were prepared by the incorporation of different amount of diethylenetriaminepentaacetic acid monopyridoxamine group (DTPA-PM) into poly-a, b-[N-(2-hydroxyethyl)-L- aspartamide] (PHEA) and poly-a, b-[N-(2-aminoethyl)-L-aspartamide] (PAEA). The macromolecular ligands thus obtained were further complexed with gadolinium chloride to give macromolecular MRI contrast agents with different Gd(Ⅲ) contents. These macromolecular ligands and their gadolinium complexes were characterized by 1H NMR, IR, UV and elementary analysis. Relaxivity studies showed that these polyaspartamide gadolinium complexes possess higher relaxation effectiveness than that of the clinically used Gd-DTPA. Magnetic resonance imaging of the liver in rats and experimental data of biodistribution in mice indicate that these macromolecular MRI contrast agents containing pyridoxamine exhibit liver-targeting property.
Tradeoffs in Design Research: Development Oriented Triangulation
Turnhout, Koen van; Craenmehr, Sabine; Holwerda, Robert; Menijn, Mark; Zwart, Jan-Pieter; Bakker, René
2013-01-01
The Development Oriented Triangulation (DOT) framework in this paper can spark and focus the debate about mixed-method approaches in HCI. The framework can be used to classify HCI methods, create mixed-method designs, and to align research activities in multidisciplinary projects. The framework is g
Tradeoffs in Design Research: Development Oriented Triangulation
Jan-Pieter Zwart; René Bakker; Robert Holwerda; Mark Menijn; Koen van Turnhout; Sabine Craenmehr
2013-01-01
The Development Oriented Triangulation (DOT) framework in this paper can spark and focus the debate about mixed-method approaches in HCI. The framework can be used to classify HCI methods, create mixed-method designs, and to align research activities in multidisciplinary projects. The framework is
A Sweepline Algorithm for Generalized Delaunay Triangulations
DEFF Research Database (Denmark)
Skyum, Sven
We give a deterministic O(n log n) sweepline algorithm to construct the generalized Voronoi diagram for n points in the plane or rather its dual the generalized Delaunay triangulation. The algorithm uses no transformations and it is developed solely from the sweepline paradigm together...
Methodological triangulation in work life research
DEFF Research Database (Denmark)
Warring, Niels
Based on examples from two research projects on preschool teachers' work, the paper will discuss potentials and challenges in methodological triangulation in work life research. Analysis of ethnographic and phenomenological inspired observations of everyday life in day care centers formed the basis...
Spectral Properties of Unimodular Lattice Triangulations
Krüger, Benedikt; Schmidt, Ella M.; Mecke, Klaus
2016-05-01
Random unimodular lattice triangulations have been recently used as an embedded random graph model, which exhibit a crossover behavior between an ordered, large-world and a disordered, small-world behavior. Using the ergodic Pachner flips that transform such triangulations into another and an energy functional that corresponds to the degree distribution variance, Markov chain Monte Carlo simulations can be applied to study these graphs. Here, we consider the spectra of the adjacency and the Laplacian matrix as well as the algebraic connectivity and the spectral radius. Power law dependencies on the system size can clearly be identified and compared to analytical solutions for periodic ground states. For random triangulations we find a qualitative agreement of the spectral properties with well-known random graph models. In the microcanonical ensemble analytical approximations agree with numerical simulations. In the canonical ensemble a crossover behavior can be found for the algebraic connectivity and the spectral radius, thus combining large-world and small-world behavior in one model. The considered spectral properties can be applied to transport problems on triangulation graphs and the crossover behavior allows a tuning of important transport quantities.
Flip to Regular Triangulation and Convex Hull.
Gao, Mingcen; Cao, Thanh-Tung; Tan, Tiow-Seng
2017-02-01
Flip is a simple and local operation to transform one triangulation to another. It makes changes only to some neighboring simplices, without considering any attribute or configuration global in nature to the triangulation. Thanks to this characteristic, several flips can be independently applied to different small, non-overlapping regions of one triangulation. Such operation is favored when designing algorithms for data-parallel, massively multithreaded hardware, such as the GPU. However, most existing flip algorithms are designed to be executed sequentially, and usually need some restrictions on the execution order of flips, making them hard to be adapted to parallel computation. In this paper, we present an in depth study of flip algorithms in low dimensions, with the emphasis on the flexibility of their execution order. In particular, we propose a series of provably correct flip algorithms for regular triangulation and convex hull in 2D and 3D, with implementations for both CPUs and GPUs. Our experiment shows that our GPU implementation for constructing these structures from a given point set achieves up to two orders of magnitude of speedup over other popular single-threaded CPU implementation of existing algorithms.
Altitude, Orthocenter of a Triangle and Triangulation
Directory of Open Access Journals (Sweden)
Coghetto Roland
2016-03-01
Full Text Available We introduce the altitudes of a triangle (the cevians perpendicular to the opposite sides. Using the generalized Ceva’s Theorem, we prove the existence and uniqueness of the orthocenter of a triangle [7]. Finally, we formalize in Mizar [1] some formulas [2] to calculate distance using triangulation.
Gaussian vector fields on triangulated surfaces
DEFF Research Database (Denmark)
Ipsen, John H
2016-01-01
proven to be very useful to resolve the complex interplay between in-plane ordering of membranes and membrane conformations. In the present work we have developed a procedure for realistic representations of Gaussian models with in-plane vector degrees of freedoms on a triangulated surface. The method...
Pre-Processing Rules for Triangulation of Probabilistic Networks
Bodlaender, H.L.; Koster, A.M.C.A.; Eijkhof, F. van den
2003-01-01
The currently most efficient algorithm for inference with a probabilistic network builds upon a triangulation of a network’s graph. In this paper, we show that pre-processing can help in finding good triangulations for probabilistic networks, that is, triangulations with a minimal maximum clique siz
Pre-processing for Triangulation of Probabilistic Networks
Bodlaender, H.L.; Koster, A.M.C.A.; Eijkhof, F. van den; Gaag, L.C. van der
2001-01-01
The currently most efficient algorithm for inference with a probabilistic network builds upon a triangulation of a networks graph. In this paper, we show that pre-processing can help in finding good triangulations for probabilistic networks, that is, triangulations with a minimal maximum clique
Pre-processing for Triangulation of Probabilistic Networks
Bodlaender, H.L.; Koster, A.M.C.A.; Eijkhof, F. van den; Gaag, L.C. van der
2001-01-01
The currently most efficient algorithm for inference with a probabilistic network builds upon a triangulation of a networks graph. In this paper, we show that pre-processing can help in finding good triangulations for probabilistic networks, that is, triangulations with a minimal maximum clique
Triangulation using synthetic aperture radar images
Wu, Sherman S. C.; Howington-Kraus, Annie E.
1991-01-01
For the extraction of topographic information about Venus from stereoradar images obtained from the Magellan Mission, a Synthetic Aperture Radar (SAR) compilation system was developed on analytical stereoplotters. The system software was extensively tested by using stereoradar images from various spacecraft and airborne radar systems, including Seasat, SIR-B, ERIM XCL, and STAR-1. Stereomodeling from radar images was proven feasible, and development is on a correct approach. During testing, the software was enhanced and modified to obtain more flexibility and better precision. Triangulation software for establishing control points by using SAR images was also developed through a joint effort with the Defense Mapping Agency. The SAR triangulation system comprises four main programs, TRIDATA, MODDATA, TRISAR, and SHEAR. The first two programs are used to sort and update the data; the third program, the main one, performs iterative statistical adjustment; and the fourth program analyzes the results. Also, input are flight data and data from the Global Positioning System and Inertial System (navigation information). The SAR triangulation system was tested with six strips of STAR-1 radar images on a VAX-750 computer. Each strip contains images of 10 minutes flight time (equivalent to a ground distance of 73.5 km); the images cover a ground width of 22.5 km. All images were collected from the same side. With an input of 44 primary control points, 441 ground control points were produced. The adjustment process converged after eight iterations. With a 6-m/pixel resolution of the radar images, the triangulation adjustment has an average standard elevation error of 81 m. Development of Magellan radargrammetry will be continued to convert both SAR compilation and triangulation systems into digital form.
COMBINED DELAUNAY TRIANGULATION AND ADAPTIVE FINITE ELEMENT METHOD FOR CRACK GROWTH ANALYSIS
Institute of Scientific and Technical Information of China (English)
Pramote DECHAUMPHAI; Sutthisak PHONGTHANAPANICH; Thanawat SRICHAROENCHAI
2003-01-01
The paper presents the utilization of the adaptive Delaunay triangulation in the finite element modeling of two dimensional crack propagation problems, including detailed description of the proposed procedure which consists of the Delaunay triangulation algorithm and an adaptive remeshing technique. The adaptive remeshing technique generates small elements around crack tips and large elements in the other regions. The resulting stress intensity factors and simulated crack propagation behavior are used to evaluate the effectiveness of the procedure. Three sample problems of a center cracked plate, a single edge cracked plate and a compact tension specimen, are simulated and their results assessed.
Temperature-dependent macromolecular X-ray crystallography
Energy Technology Data Exchange (ETDEWEB)
Weik, Martin, E-mail: martin.weik@ibs.fr; Colletier, Jacques-Philippe [CEA, IBS, Laboratoire de Biophysique Moléculaire, F-38054 Grenoble (France); CNRS, UMR5075, F-38027 Grenoble (France); Université Joseph Fourier, F-38000 Grenoble (France)
2010-04-01
The dynamical behaviour of crystalline macromolecules and their surrounding solvent as a function of cryo-temperature is reviewed. X-ray crystallography provides structural details of biological macromolecules. Whereas routine data are collected close to 100 K in order to mitigate radiation damage, more exotic temperature-controlled experiments in a broader temperature range from 15 K to room temperature can provide both dynamical and structural insights. Here, the dynamical behaviour of crystalline macromolecules and their surrounding solvent as a function of cryo-temperature is reviewed. Experimental strategies of kinetic crystallography are discussed that have allowed the generation and trapping of macromolecular intermediate states by combining reaction initiation in the crystalline state with appropriate temperature profiles. A particular focus is on recruiting X-ray-induced changes for reaction initiation, thus unveiling useful aspects of radiation damage, which otherwise has to be minimized in macromolecular crystallography.
Extending particle tracking capability with Delaunay triangulation.
Chen, Kejia; Anthony, Stephen M; Granick, Steve
2014-04-29
Particle tracking, the analysis of individual moving elements in time series of microscopic images, enables burgeoning new applications, but there is need to better resolve conformation and dynamics. Here we describe the advantages of Delaunay triangulation to extend the capabilities of particle tracking in three areas: (1) discriminating irregularly shaped objects, which allows one to track items other than point features; (2) combining time and space to better connect missing frames in trajectories; and (3) identifying shape backbone. To demonstrate the method, specific examples are given, involving analyzing the time-dependent molecular conformations of actin filaments and λ-DNA. The main limitation of this method, shared by all other clustering techniques, is the difficulty to separate objects when they are very close. This can be mitigated by inspecting locally to remove edges that are longer than their neighbors and also edges that link two objects, using methods described here, so that the combination of Delaunay triangulation with edge removal can be robustly applied to processing large data sets. As common software packages, both commercial and open source, can construct Delaunay triangulation on command, the methods described in this paper are both computationally efficient and easy to implement.
Dynamic ray tracing and its application in triangulated media
Energy Technology Data Exchange (ETDEWEB)
Rueger, A.
1993-07-01
Hale and Cohen (1991) developed software to generate two-dimensional computer models of complex geology. Their method uses a triangulation technique designed to support efficient and accurate computation of seismic wavefields for models of the earth`s interior. Subsequently, Hale (1991) used this triangulation approach to perform dynamic ray tracing and create synthetic seismograms based on the method of Gaussian beams. Here, I extend this methodology to allow an increased variety of ray-theoretical experiments. Specifically, the developed program GBmod (Gaussian Beam MODeling) can produce arbitrary multiple sequences and incorporate attenuation and density variations. In addition, I have added an option to perform Fresnel-volume ray tracing (Cerveny and Soares, 1992). Corrections for reflection and transmission losses at interfaces, and for two-and-one-half-dimensional (2.5-D) spreading are included. However, despite these enhancements, difficulties remain in attempts to compute accurate synthetic seismograms if strong lateral velocity inhomogeneities are present. Here, these problems are discussed and, to a certain extent, reduced. I provide example computations of high-frequency seismograms based on the method of Gaussian beams to exhibit the advantages and disadvantages of the proposed modeling method and illustrate new features for both surface and vertical seismic profiling (VSP) acquisition geometries.
Computing 2D constrained delaunay triangulation using the GPU.
Qi, Meng; Cao, Thanh-Tung; Tan, Tiow-Seng
2013-05-01
We propose the first graphics processing unit (GPU) solution to compute the 2D constrained Delaunay triangulation (CDT) of a planar straight line graph (PSLG) consisting of points and edges. There are many existing CPU algorithms to solve the CDT problem in computational geometry, yet there has been no prior approach to solve this problem efficiently using the parallel computing power of the GPU. For the special case of the CDT problem where the PSLG consists of just points, which is simply the normal Delaunay triangulation (DT) problem, a hybrid approach using the GPU together with the CPU to partially speed up the computation has already been presented in the literature. Our work, on the other hand, accelerates the entire computation on the GPU. Our implementation using the CUDA programming model on NVIDIA GPUs is numerically robust, and runs up to an order of magnitude faster than the best sequential implementations on the CPU. This result is reflected in our experiment with both randomly generated PSLGs and real-world GIS data having millions of points and edges.
Analysis of Tagish Lake macromolecular organic material
Gilmour, I; Pearson, V. K.; Sephton, M.A.
2001-01-01
Macromolecular material is, by far, the major organic component of meteorites. Flash pyrolysis GCMS has been used to investigate this organic component in Tagish Lake. It is more condensed, less susbtituted than Murchson.
Automated data collection for macromolecular crystallography.
Winter, Graeme; McAuley, Katherine E
2011-09-01
An overview, together with some practical advice, is presented of the current status of the automation of macromolecular crystallography (MX) data collection, with a focus on MX beamlines at Diamond Light Source, UK.
Macromolecular crowding: Macromolecules friend or foe.
Mittal, Shruti; Chowhan, Rimpy Kaur; Singh, Laishram Rajendrakumar
2015-09-01
Cellular interior is known to be densely crowded due to the presence of soluble and insoluble macromolecules, which altogether occupy ~40% of the total cellular volume. This results in altered biological properties of macromolecules. Macromolecular crowding is observed to have both positive and negative effects on protein folding, structure, stability and function. Significant data has been accumulated so far on both the aspects. However, most of the review articles so far have focused on the positive aspect of macromolecular crowding and not much attention has been paid on the deleterious aspect of crowding on macromolecules. In order to have a complete knowledge of the effect of macromolecular crowding on proteins and enzymes, it is important to look into both the aspects of crowding to determine its precise role under physiological conditions. To fill the gap in the understanding of the effect of macromolecular crowding on proteins and enzymes, this review article focuses on the deleterious influence of crowding on macromolecules. Macromolecular crowding is not always good but also has several deleterious effects on various macromolecular properties. Taken together, the properties of biological macromolecules in vivo appears to be finely regulated by the nature and level of the intracellular crowdedness in order to perform their biological functions appropriately. The information provided here gives an understanding of the role played by the nature and level of cellular crowdedness in intensifying and/or alleviating the burden of various proteopathies. Copyright © 2015 Elsevier B.V. All rights reserved.
Energy transfer in macromolecular arrays
Andrews, David L.; Jenkins, Robert D.
2003-11-01
Macromolecular systems comprised of many light-sensitive centres (the photosynthetic unit, dendrimers, and other highly symmetric multichromophore arrays) are important structures offering challenges to theoreticians and synthetic chemists alike. Here we outline novel photophysical interactions predicted and observed in such arrays. Using the tools of molecular quantum electrodynamics (QED) we present quantum amplitudes for a variety of higher-order resonance energy transfer (RET) schemes associated with well-known nonlinear optical effects such as two- and three-photon absorption. The initial analysis is extended to account for situations where the participant donor species are identical and exist in a highly symmetric environment, leading to the possible formation of excitons. It emerges from the QED theory that such excitons are closely associated with the higher-order RET processes. General results are interpreted by analyzing particular molecular architectures which offer interesting features such as rate enhancement or limitation and exciton pathway quenching. Applications in the areas of photosynthesis, molecular logic gates and low-intensity fluorescence energy transfer are predicted.
带约束折线的平面散点集Delaunay三角剖分%Delaunay Triangulation of 2D Scattered Point Set with Constrained Polylines
Institute of Scientific and Technical Information of China (English)
王中辉; 闫浩文
2011-01-01
This paper first triangulates the original scattered points with all constrained points to form the initial Delaunay triangulation. Then each constrained segment is embedded in the existent triangulation in turn through local updating, eventually to form the Delannay triangulation with constrained polylines. The algorithm is concise and easy to program and the generated triangulation is in good shape.%首先将原始散点与约束点一起进行三角剖分,形成初始Delaunay三角网,然后再将各条约束线段通过局部更新,依次嵌入已存在的三角网中,从而生成带有约束折线的平面散点集的Delaunay三角剖分.该算法思路简捷,易于编程,生成的三角网形态优良.
Metodologisk triangulering i arbejdslivsforskning – potentialer og udfordringer
DEFF Research Database (Denmark)
Warring, Niels
2015-01-01
Metodologisk triangulering i arbejdslivsforskning – potentialer og udfordringer Med inddragelse af eksempler fra to forskningsprojekter om pædagogers arbejdsliv, vil der blive argumenteret for det frugtbare i metodologisk triangulering, når der forskes i moderne arbejdsliv – og ikke mindst, når...... ambitionen er at bidrage til at åbne for kritiske perspektiver og mulige forandringspotentialer. I de to projekter var etnografisk og fænomenologisk inspirerede observationer af hverdagen i daginstitutionerne første skridt i den metodologiske triangulering. Tolkning og analyse af scener fra hverdagen dannede...... udviklede sig i dialog med deltagernes såvel praktiske hverdagsviden som teoretisk baserede pædagogisk-faglige viden. Metodologisk triangulering er af Denzin (opr. 1970) foreslået som en blandt flere former for triangulering. Øvrige former er teoretisk triangulering (hvor flere teorier benyttes til at tolke...
Implementing a triangulation protocol in bereavement research: a methodological discussion.
Briller, Sherylyn H; Meert, Kathleen L; Schim, Stephanie Myers; Thurston, Celia S; Kabel, Allison
2008-01-01
Triangulation is a comparative strategy for examining data that strengthens qualitative and multi-method research. Despite the benefits of triangulation noted in the research methods literature, few concrete models for operationalization of protocols exist. Lack of documentation of explicit triangulation procedures is especially true in the area of bereavement research. This article describes how an interdisciplinary research team implemented a triangulation protocol in a study of the needs of bereaved parents. Triangulation enabled the integration of diverse data sources, methods, and disciplinary perspectives. These processes yielded a more meaningful typology of bereaved parents' needs than would have otherwise been possible. Extending the use of triangulation will enhance multi-faceted understandings of bereavement.
Duals of Orphan-Free Anisotropic Voronoi Diagrams are Triangulations
Canas, Guillermo D
2011-01-01
We show that, under mild conditions on the underlying metric, duals of appropriately defined anisotropic Voronoi diagrams are embedded triangulations. Furthermore, they always triangulate the convex hull of the vertices, and have other properties that parallel those of ordinary Delaunay triangulations. These results apply to the duals of anisotropic Voronoi diagrams of any set of vertices, so long as the diagram is orphan-free.
Wilson Fermions on a Randomly Triangulated Manifold
Burda, Z; Krzywicki, A
1999-01-01
A general method of constructing the Dirac operator for a randomly triangulated manifold is proposed. The fermion field and the spin connection live, respectively, on the nodes and on the links of the corresponding dual graph. The construction is carried out explicitly in 2-d, on an arbitrary orientable manifold without boundary. It can be easily converted into a computer code. The equivalence, on a sphere, of Majorana fermions and Ising spins in 2-d is rederived. The method can, in principle, be extended to higher dimensions.
Diffractive triangulation of radiative point sources
Vespucci, Stefano; Maneuski, Dzmitry; O'Shea, Val; Winkelmann, Aimo
2016-01-01
We describe a general method to determine the location of a point source of waves relative to a two-dimensional active pixel detector. Based on the inherent structural sensitivity of crystalline sensor materials, characteristic detector diffraction patterns can be used to triangulate the location of a wave emitter. As a practical application of the wide-ranging principle, a digital hybrid pixel detector is used to localize a source of electrons for Kikuchi diffraction pattern measurements in the scanning electron microscope. This provides a method to calibrate Kikuchi diffraction patterns for accurate measurements of microstructural crystal orientations, strains, and phase distributions.
Skin lesion image segmentation using Delaunay Triangulation for melanoma detection.
Pennisi, Andrea; Bloisi, Domenico D; Nardi, Daniele; Giampetruzzi, Anna Rita; Mondino, Chiara; Facchiano, Antonio
2016-09-01
Developing automatic diagnostic tools for the early detection of skin cancer lesions in dermoscopic images can help to reduce melanoma-induced mortality. Image segmentation is a key step in the automated skin lesion diagnosis pipeline. In this paper, a fast and fully-automatic algorithm for skin lesion segmentation in dermoscopic images is presented. Delaunay Triangulation is used to extract a binary mask of the lesion region, without the need of any training stage. A quantitative experimental evaluation has been conducted on a publicly available database, by taking into account six well-known state-of-the-art segmentation methods for comparison. The results of the experimental analysis demonstrate that the proposed approach is highly accurate when dealing with benign lesions, while the segmentation accuracy significantly decreases when melanoma images are processed. This behavior led us to consider geometrical and color features extracted from the binary masks generated by our algorithm for classification, achieving promising results for melanoma detection.
Computational Hardness of Enumerating Satisfying Spin-Assignments in Triangulations
Jiménez, Andrea
2011-01-01
Satisfying spin-assignments in triangulations of a surface are states of minimum energy of the antiferromagnetic Ising model on triangulations which correspond (via geometric duality) to perfect matchings in cubic bridgeless graphs. In this work we show that it is NP-complete to decide whether or not a surface triangulation admits a satisfying spin-assignment, and that it is #P-complete to determine the number of such assignments. Both results are derived via an elaborate (and atypical) reduction that maps a Boolean formula in 3-conjunctive normal form into a triangulation of an orientable closed surface.
TRIANGULATION OF METHODS OF CAREER EDUCATION
Directory of Open Access Journals (Sweden)
Marija Turnsek Mikacic
2015-09-01
Full Text Available This paper is an overview of the current research in the field of career education and career planning. Presented results constitute a model based on the insight into different theories and empirical studies about career planning as a building block of personal excellence. We defined credibility, transferability and reliability of the research by means of triangulation. As sources of data of triangulation we included essays of participants of education and questionnaires. Qualitative analysis represented the framework for the construction of the paradigmatic model and the formulation of the final theory. We formulated a questionnaire on the basis of our own experiences in the area of the education of individuals. The quantitative analysis, based on the results of the interviews, confirms the following three hypotheses: The individuals who elaborated a personal career plan and acted accordingly, changed their attitudes towards their careers and took control over their lives; in addition, they achieved a high level of self-esteem and self-confidence, in tandem with the perception of personal excellence, in contrast to the individuals who did not participate in career education and did not elaborate a career plan. We used the tools of NLP (neurolinguistic programming as an additional technique at learning.
Good Random Multi-Triangulation of Surfaces.
de Medeiros Filho, Esdras; Siqueira, Marcelo
2017-05-12
We introduce the Hierarchical Poisson Disk Sampling Multi-Triangulation (HPDS-MT) of surfaces, a novel structure that combines the power of multi-triangulation (MT) with the benefits of Hierarchical Poisson Disk Sampling (HPDS). MT is a general framework for representing surfaces through variable resolution triangle meshes, while HPDS is a well-spaced random distribution with blue noise characteristics. The distinguishing feature of the HPDS-MT is its ability to extract adaptive meshes whose triangles are guaranteed to have good shape quality. The key idea behind the HPDS-MT is a preprocessed hierarchy of points, which is used in the construction of a MT via incremental simplification. In addition to proving theoretical properties on the shape quality of the triangle meshes extracted by the HPDS-MT, we provide an implementation that computes the HPDS-MT with high accuracy. Our results confirm the theoretical guarantees and outperform similar methods. We also prove that the Hausdorff distance between the original surface and any (extracted) adaptive mesh is bounded by the sampling distribution of the radii of Poisson-disks over the surface. Finally, we illustrate the advantages of the HPDS-MT in some typical problems of geometry processing.
Surface roughness measurement with laser triangulation
Bai, Fuzhong; Zhang, Xiaoyan; Tian, Chaoping
2016-09-01
A surface roughness measurement method is introduced in the paper, which is based on laser triangulation and digital image processing technique. In the measuring system, we use the line-structured light as light source, microscope lens and high-accuracy CCD sensor as displacement sensor as well. In addition, the working angle corresponding to the optimal sensitivity is considered in the optical structure design to improve the measuring accuracy. Through necessary image processing operation for the light strip image, such as center-line extraction with the barycenter algorithm, Gaussian filtering, the value of roughness is calculated. A standard planing surface is measured experimentally with the proposed method and the stylus method (Mitutoyo SJ-410) respectively. The profilograms of surface appearance are greatly similar in the shape and the amplitude to two methods. Also, the roughness statistics values are close. The results indicate that the laser triangulation with the line-structured light can be applied to measure the surface roughness with the advantages of rapid measurement and visualized display of surface roughness profile.
Effects of macromolecular crowding on genetic networks.
Morelli, Marco J; Allen, Rosalind J; Wolde, Pieter Rein ten
2011-12-21
The intracellular environment is crowded with proteins, DNA, and other macromolecules. Under physiological conditions, macromolecular crowding can alter both molecular diffusion and the equilibria of bimolecular reactions and therefore is likely to have a significant effect on the function of biochemical networks. We propose a simple way to model the effects of macromolecular crowding on biochemical networks via an appropriate scaling of bimolecular association and dissociation rates. We use this approach, in combination with kinetic Monte Carlo simulations, to analyze the effects of crowding on a constitutively expressed gene, a repressed gene, and a model for the bacteriophage λ genetic switch, in the presence and absence of nonspecific binding of transcription factors to genomic DNA. Our results show that the effects of crowding are mainly caused by the shift of association-dissociation equilibria rather than the slowing down of protein diffusion, and that macromolecular crowding can have relevant and counterintuitive effects on biochemical network performance.
Accuracy analysis for triangulation and tracking based on time-multiplexed structured light.
Wagner, Benjamin; Stüber, Patrick; Wissel, Tobias; Bruder, Ralf; Schweikard, Achim; Ernst, Floris
2014-08-01
The authors' research group is currently developing a new optical head tracking system for intracranial radiosurgery. This tracking system utilizes infrared laser light to measure features of the soft tissue on the patient's forehead. These features are intended to offer highly accurate registration with respect to the rigid skull structure by means of compensating for the soft tissue. In this context, the system also has to be able to quickly generate accurate reconstructions of the skin surface. For this purpose, the authors have developed a laser scanning device which uses time-multiplexed structured light to triangulate surface points. The accuracy of the authors' laser scanning device is analyzed and compared for different triangulation methods. These methods are given by the Linear-Eigen method and a nonlinear least squares method. Since Microsoft's Kinect camera represents an alternative for fast surface reconstruction, the authors' results are also compared to the triangulation accuracy of the Kinect device. Moreover, the authors' laser scanning device was used for tracking of a rigid object to determine how this process is influenced by the remaining triangulation errors. For this experiment, the scanning device was mounted to the end-effector of a robot to be able to calculate a ground truth for the tracking. The analysis of the triangulation accuracy of the authors' laser scanning device revealed a root mean square (RMS) error of 0.16 mm. In comparison, the analysis of the triangulation accuracy of the Kinect device revealed a RMS error of 0.89 mm. It turned out that the remaining triangulation errors only cause small inaccuracies for the tracking of a rigid object. Here, the tracking accuracy was given by a RMS translational error of 0.33 mm and a RMS rotational error of 0.12°. This paper shows that time-multiplexed structured light can be used to generate highly accurate reconstructions of surfaces. Furthermore, the reconstructed point sets can be
Macromolecular mimicry of nucleic acid and protein
DEFF Research Database (Denmark)
Nautrup Pedersen, Gitte; Nyborg, Jens; Clark, Brian F
1999-01-01
of the concept of macromolecular mimicry. Macromolecular mimicry has further been proposed among initiation and release factors, thereby adding a new element to the description of protein synthesis in bacteria. Such mimicry has also been observed in other biological processes such as autoimmunity, DNA repair......Although proteins and nucleic acids consist of different chemical components, proteins can mimic structures and possibly also functions of nucleic acids. Recently, structural mimicry was observed between two elongation factors in bacterial protein biosynthesis leading to the introduction...
Macromolecular networks and intelligence in microorganisms
Directory of Open Access Journals (Sweden)
Hans V Westerhoff
2014-07-01
Full Text Available Living organisms persist by virtue of complex interactions among many components organized into dynamic, environment-responsive networks that span multiple scales and dimensions. Biological networks constitute a type of Information and Communication Technology (ICT: they receive information from the outside and inside of cells, integrate and interpret this information, and then activate a response. Biological networks enable molecules within cells, and even cells themselves, to communicate with each other and their environment. We have become accustomed to associating brain activity – particularly activity of the human brain – with a phenomenon we call intelligence. Yet, four billion years of evolution could have selected networks with topologies and dynamics that confer traits analogous to this intelligence, even though they were outside the intercellular networks of the brain. Here, we explore how macromolecular networks in microbes confer intelligent characteristics, such as memory, anticipation, adaptation and reflection and we review current understanding of how network organization reflects the type of intelligence required for the environments in which they were selected. We propose that, if we were to leave terms such as human and brain out of the defining features of intelligence, all forms of life – from microbes to humans – exhibit some or all characteristics consistent with intelligence. We then review advances in genome-wide data production and analysis, especially in microbes, that provide a lens into microbial intelligence and propose how the insights derived from quantitatively characterizing biomolecular networks may enable synthetic biologists to create intelligent molecular networks for biotechnology, possibly generating new forms of intelligence, first in silico and then in vivo.
Macromolecular networks and intelligence in microorganisms
Westerhoff, Hans V.; Brooks, Aaron N.; Simeonidis, Evangelos; García-Contreras, Rodolfo; He, Fei; Boogerd, Fred C.; Jackson, Victoria J.; Goncharuk, Valeri; Kolodkin, Alexey
2014-01-01
Living organisms persist by virtue of complex interactions among many components organized into dynamic, environment-responsive networks that span multiple scales and dimensions. Biological networks constitute a type of information and communication technology (ICT): they receive information from the outside and inside of cells, integrate and interpret this information, and then activate a response. Biological networks enable molecules within cells, and even cells themselves, to communicate with each other and their environment. We have become accustomed to associating brain activity – particularly activity of the human brain – with a phenomenon we call “intelligence.” Yet, four billion years of evolution could have selected networks with topologies and dynamics that confer traits analogous to this intelligence, even though they were outside the intercellular networks of the brain. Here, we explore how macromolecular networks in microbes confer intelligent characteristics, such as memory, anticipation, adaptation and reflection and we review current understanding of how network organization reflects the type of intelligence required for the environments in which they were selected. We propose that, if we were to leave terms such as “human” and “brain” out of the defining features of “intelligence,” all forms of life – from microbes to humans – exhibit some or all characteristics consistent with “intelligence.” We then review advances in genome-wide data production and analysis, especially in microbes, that provide a lens into microbial intelligence and propose how the insights derived from quantitatively characterizing biomolecular networks may enable synthetic biologists to create intelligent molecular networks for biotechnology, possibly generating new forms of intelligence, first in silico and then in vivo. PMID:25101076
Triangulation, Respondent Validation, and Democratic Participation in Mixed Methods Research
Torrance, Harry
2012-01-01
Over the past 10 years or so the "Field" of "Mixed Methods Research" (MMR) has increasingly been exerting itself as something separate, novel, and significant, with some advocates claiming paradigmatic status. Triangulation is an important component of mixed methods designs. Triangulation has its origins in attempts to validate research findings…
Triangulation, Respondent Validation, and Democratic Participation in Mixed Methods Research
Torrance, Harry
2012-01-01
Over the past 10 years or so the "Field" of "Mixed Methods Research" (MMR) has increasingly been exerting itself as something separate, novel, and significant, with some advocates claiming paradigmatic status. Triangulation is an important component of mixed methods designs. Triangulation has its origins in attempts to validate research findings…
Graph Triangulations and the Compatibility of Unrooted Phylogenetic Trees
Vakati, Sudheer
2010-01-01
We characterize the compatibility of a collection of unrooted phylogenetic trees as a question of determining whether a graph derived from these trees --- the display graph --- has a specific kind of triangulation, which we call legal. Our result is a counterpart to the well known triangulation-based characterization of the compatibility of undirected multi-state characters.
I/O-Efficient Construction of Constrained Delaunay Triangulations
DEFF Research Database (Denmark)
Agarwal, Pankaj Kumar; Arge, Lars; Yi, Ke
2005-01-01
In this paper, we designed and implemented an I/O-efficient algorithm for constructing constrained Delaunay triangulations. If the number of constraining segments is smaller than the memory size, our algorithm runs in expected O( N B logM/B NB ) I/Os for triangulating N points in the plane, where M...
Measuring and Controlling Fairness of Triangulations
Jiang, Caigui
2016-09-30
The fairness of meshes that represent geometric shapes is a topic that has been studied extensively and thoroughly. However, the focus in such considerations often is not on the mesh itself, but rather on the smooth surface approximated by it, and fairness essentially expresses a mesh’s suitability for purposes such as visualization or simulation. This paper focusses on meshes in the architectural context, where vertices, edges, and faces of meshes are often highly visible, and any notion of fairness must take new aspects into account. We use concepts from discrete differential geometry (star-shaped Gauss images) to express fairness, and we also demonstrate how fairness can be incorporated into interactive geometric design of triangulated freeform skins.
New deghosting method based on generalized triangulation
Institute of Scientific and Technical Information of China (English)
Bai Jing; Wang Guohong; Xiu Jianjuan; Wang Xiaobo
2009-01-01
A new deghosting method baaed on the generalized triangulation is presented. First, two intersection points corresponding to the emitter position are obtained by utilizing two azimuth angles and two elevation angles from two jammed 3-D radars (or 2-D passive sensors). Then, hypothesis testing baaed deghosting method in the multiple target scenarios is proposed using the two intersection points. In order to analyze the performance of the proposed method, the correct association probability of the true targets and the incorrect association probability of the ghost targets are defined. Finally, the Monte Carlo simulations are given for the proposed method compared with the hinge angle method in the cases of both two and three radars. The simulation results show that the proposed method has better performance than the hinge angle method in three radars case.
Exploring Torus Universes in Causal Dynamical Triangulations
DEFF Research Database (Denmark)
Budd, Timothy George; Loll, R.
2013-01-01
Motivated by the search for new observables in nonperturbative quantum gravity, we consider Causal Dynamical Triangulations (CDT) in 2+1 dimensions with the spatial topology of a torus. This system is of particular interest, because one can study not only the global scale factor, but also global...... shape variables in the presence of arbitrary quantum fluctuations of the geometry. Our initial investigation focusses on the dynamics of the scale factor and uncovers a qualitatively new behaviour, which leads us to investigate a novel type of boundary conditions for the path integral. Comparing large......-scale features of the emergent quantum geometry in numerical simulations with a classical minisuperspace formulation, we find partial agreement. By measuring the correlation matrix of volume fluctuations we succeed in reconstructing the effective action for the scale factor directly from the simulation data...
Exploring Torus Universes in Causal Dynamical Triangulations
Budd, T G
2013-01-01
Motivated by the search for new observables in nonperturbative quantum gravity, we consider Causal Dynamical Triangulations (CDT) in 2+1 dimensions with the spatial topology of a torus. This system is of particular interest, because one can study not only the global scale factor, but also global shape variables in the presence of arbitrary quantum fluctuations of the geometry. Our initial investigation focusses on the dynamics of the scale factor and uncovers a qualitatively new behaviour, which leads us to investigate a novel type of boundary conditions for the path integral. Comparing large-scale features of the emergent quantum geometry in numerical simulations with a classical minisuperspace formulation, we find partial agreement. By measuring the correlation matrix of volume fluctuations we succeed in reconstructing the effective action for the scale factor directly from the simulation data. Apart from setting the stage for the analysis of shape dynamics on the torus, the new set-up highlights the role o...
Employee-satisfaction: A triangulation approach
Directory of Open Access Journals (Sweden)
P. J. Visser
1997-06-01
Full Text Available The research on employee-satisfaction was conducted in the manufacturing industry. The sample consisted of 543 employees. The methodology could be described as a "triangulation approach" where a combination of quantitative and qualitative measurements were utilised and the results of both types of measurement integrated in the study of the construct. The research confirms existing findings that although the measurement of dimensions such as equitable rewards, working conditions, supportive colleagues, job content, etc. yield results on the level of employee-satisfaction, a single question, namely, "How satisfied are you with your job?" compares favourably with the general index. The findings also suggest the advantage of complimenting the quantitative data with qualitative information. The conclusions confirm the value of a qualitative method in cross-cultural research in an African environment. Opsomming Die navorsing omtrent werknemerstevredenheid is uitgevoer in die vervaardigingsbedryf. Die steekproef het bestaan uit 543 werknemers. Die metode van ondersoek kan beskryf word as 'n "driekantige benadering" (triangulation approach waar daar van kwantitatiewe en kwalitatiewe meting gebruik gemaak is en die resultate geihtegreer is in die bestudering van die konstruk. Die navorsing bevestig bestaande bevindinge dat die meting van dimensies soos vergelykbare belonings, werkstoestande, ondersteunende kollegas, inhoud van werk, ens. resultate lewer rakende die vlak van werknemerstevredenheid, 'n enkel vraag, naamlik, "Hoe tevrede is jy met jou werk?" gunstig vergelyk met die algemene indeks. Die bevindinge dui ook op die voordele van 'n benadering waar die kwantitatiewe data gekomplimenteer word deur kwalitatiewe inligting soos verkry uit individuele onderhoude. Die gevolgtrekkings bevestig die waarde wat die kwalitatiewe navorsingsmetode inhou vir kruis-kulturele navorsing in 'n Afrika konteks.
Efficient triangulation of Poisson-disk sampled point sets
Guo, Jianwei
2014-05-06
In this paper, we present a simple yet efficient algorithm for triangulating a 2D input domain containing a Poisson-disk sampled point set. The proposed algorithm combines a regular grid and a discrete clustering approach to speedup the triangulation. Moreover, our triangulation algorithm is flexible and performs well on more general point sets such as adaptive, non-maximal Poisson-disk sets. The experimental results demonstrate that our algorithm is robust for a wide range of input domains and achieves significant performance improvement compared to the current state-of-the-art approaches. © 2014 Springer-Verlag Berlin Heidelberg.
Macromolecular crystallization and crystal perfection
Chayen, Naomi E; Snell, Edward H
2010-01-01
Structural biology is key to our understanding of the mechanisms of biological processes. This text describes current methods and future frontiers in crystal growth and use of X-ray and neutron crystallography, in the context of automation of crystallization and generation of synchrotron X-ray and neutron beams.
Identifying and visualizing macromolecular flexibility in structural biology
Directory of Open Access Journals (Sweden)
Martina Palamini
2016-09-01
Full Text Available Structural biology comprises a variety of tools to obtain atomic resolution data for the investigation of macromolecules. Conventional structural methodologies including crystallography, NMR and electron microscopy often do not provide sufficient details concerning flexibility and dynamics, even though these aspects are critical for the physiological functions of the systems under investigation. However, the increasing complexity of the molecules studied by structural biology (including large macromolecular assemblies, integral membrane proteins, intrinsically disordered systems, and folding intermediates continuously demands in-depth analyses of the roles of flexibility and conformational specificity involved in interactions with ligands and inhibitors. The intrinsic difficulties in capturing often subtle but critical molecular motions in biological systems have restrained the investigation of flexible molecules into a small niche of structural biology. Introduction of massive technological developments over the recent years, which include time-resolved studies, solution X-ray scattering, and new detectors for cryo-electron microscopy, have pushed the limits of structural investigation of flexible systems far beyond traditional approaches of NMR analysis. By integrating these modern methods with powerful biophysical and computational approaches such as generation of ensembles of molecular models and selective particle picking in electron microscopy, more feasible investigations of dynamic systems are now possible. Using some prominent examples from recent literature, we review how current structural biology methods can contribute useful data to accurately visualize flexibility in macromolecular structures and understand its important roles in regulation of biological processes.
The macromolecular crystallography facility at the advanced light source
Earnest, Thomas; Padmore, Howard; Cork, Carl; Behrsing, Rolf; Kim, Sung-Hou
1996-10-01
Synchrotron radiation offers several advantages over the use of rotating anode sources for biological crystallography, which allow for the collection of higher-resolution data, substantially more rapid data collection, phasing by multiwavelength anomalous diffraction (MAD) techniques, and time-resolved experiments using polychromatic radiation (Laue diffraction). The use of synchrotron radiation is often necessary to record useful data from crystals which diffract weakly or have very large unit cells. The high brightness and stability characteristics of the advanced light source (ALS) at Lawrence Berkeley National Laboratory, along with the low emittance and long straight sections to accommodate insertion devices present in third generation synchrotrons like the ALS, lead to several advantages in the field of macromolecular crystallography. We are presently constructing a macromolecular crystallography facility at the ALS which is optimized for user-friendliness and high-throughput data collection, with advanced capabilities for MAD and Laue experiments. The X-rays will be directed to three branchlines. A well-equipped support lab will be available for biochemistry, crystal mounting and sample storage, as well as computer hardware and software available, along with staff support, allowing for the complete processing of data on site.
Detection method of inclination angle in image measurement based on improved triangulation.
Zhang, Jinfeng; Zhang, Jiye
2015-02-01
Image distortion seriously affects the accuracy in microscope image measurement. One source of such distortion is related to the tilting of the microscope stage during laser scanning, thereby resulting in various degrees of inclination angles. This paper describes a novel technique that improves the traditional laser triangulation method by using multiple parallel laser beams that can solve the inclination problem. Moreover, a multi-light-spot measurement device, based on the improved laser triangulation technique, is proposed that can accurately detect the degree and directions of the inclination angles in real time. Furthermore, experimental results generated from a prototype of this device show that the new measurement system can effectively detect small inclination angles at a precision up to ±0.5 μrad.
Statistics of Multiscale Fluctuations in Macromolecular Systems
Yukalov, V I
2012-01-01
An approach is suggested for treating multiscale fluctuations in macromolecular systems. The emphasis is on the statistical properties of such fluctuations. The approach is illustrated by a macromolecular system with mesoscopic fluctuations between the states of atomic orbitals. Strong-orbital and weak-orbital couplings fluctuationally arise, being multiscale in space and time. Statistical properties of the system are obtained by averaging over the multiscale fluctuations. The existence of such multiscale fluctuations causes phase transitions between strong-coupling and weak-coupling states. These transitions are connected with structure and size transformations of macromolecules. An approach for treating density and size multiscale fluctuations by means of classical statistical mechanics is also advanced.
In situ macromolecular crystallography using microbeams.
Axford, Danny; Owen, Robin L; Aishima, Jun; Foadi, James; Morgan, Ann W; Robinson, James I; Nettleship, Joanne E; Owens, Raymond J; Moraes, Isabel; Fry, Elizabeth E; Grimes, Jonathan M; Harlos, Karl; Kotecha, Abhay; Ren, Jingshan; Sutton, Geoff; Walter, Thomas S; Stuart, David I; Evans, Gwyndaf
2012-05-01
Despite significant progress in high-throughput methods in macromolecular crystallography, the production of diffraction-quality crystals remains a major bottleneck. By recording diffraction in situ from crystals in their crystallization plates at room temperature, a number of problems associated with crystal handling and cryoprotection can be side-stepped. Using a dedicated goniometer installed on the microfocus macromolecular crystallography beamline I24 at Diamond Light Source, crystals have been studied in situ with an intense and flexible microfocus beam, allowing weakly diffracting samples to be assessed without a manual crystal-handling step but with good signal to noise, despite the background scatter from the plate. A number of case studies are reported: the structure solution of bovine enterovirus 2, crystallization screening of membrane proteins and complexes, and structure solution from crystallization hits produced via a high-throughput pipeline. These demonstrate the potential for in situ data collection and structure solution with microbeams.
Growth and dissolution of macromolecular Markov chains
Gaspard, Pierre
2016-01-01
The kinetics and thermodynamics of free living copolymerization are studied for processes with rates depending on k monomeric units of the macromolecular chain behind the unit that is attached or detached. In this case, the sequence of monomeric units in the growing copolymer is a kth-order Markov chain. In the regime of steady growth, the statistical properties of the sequence are determined analytically in terms of the attachment and detachment rates. In this way, the mean growth velocity as well as the thermodynamic entropy production and the sequence disorder can be calculated systematically. These different properties are also investigated in the regime of depolymerization where the macromolecular chain is dissolved by the surrounding solution. In this regime, the entropy production is shown to satisfy Landauer's principle.
Growth and Dissolution of Macromolecular Markov Chains
Gaspard, Pierre
2016-07-01
The kinetics and thermodynamics of free living copolymerization are studied for processes with rates depending on k monomeric units of the macromolecular chain behind the unit that is attached or detached. In this case, the sequence of monomeric units in the growing copolymer is a kth-order Markov chain. In the regime of steady growth, the statistical properties of the sequence are determined analytically in terms of the attachment and detachment rates. In this way, the mean growth velocity as well as the thermodynamic entropy production and the sequence disorder can be calculated systematically. These different properties are also investigated in the regime of depolymerization where the macromolecular chain is dissolved by the surrounding solution. In this regime, the entropy production is shown to satisfy Landauer's principle.
From Causal Dynamical Triangulations To Astronomical Observations
Mielczarek, Jakub
2015-01-01
This essay discusses phenomenological aspects of the diffusion time dependence of the spectral dimension predicted by the Causal Dynamical Triangulations (CDT) approach to quantum gravity. The deformed form of the dispersion relation for the fields defined on the CDT space-time is reconstructed. Using the \\emph{Fermi} satellite observations of the GRB 090510 source we find that the energy scale of the dimensional reduction is $E_* > 6.7 \\cdot 10^{10}$ GeV at (95 $\\%$ CL). By applying the deformed dispersion relation to the cosmological perturbations it is shown that, for a scenario when the primordial perturbations are formed in the UV region, the scalar power spectrum $\\mathcal{P}_S \\propto k^{n_S-1}$ where $n_S-1\\approx \\frac{3r(d_{\\rm UV}-2)}{r+48(d_{\\rm UV}-3)}$. Here, $d_{\\rm UV} \\approx 2$ is obtained from the CDT value of the spectral dimension in the UV limit and $r$ is the tensor-to-scalar ratio. We find that, the predicted deviation from the scale-invariance ($n_S=1$) is in contradiction with the up...
Blind guidance system based on laser triangulation
Wu, Jih-Huah; Wang, Jinner-Der; Fang, Wei; Lee, Yun-Parn; Shan, Yi-Chia; Kao, Hai-Ko; Ma, Shih-Hsin; Jiang, Joe-Air
2012-05-01
We propose a new guidance system for the blind. An optical triangulation method is used in the system. The main components of the proposed system comprise of a notebook computer, a camera, and two laser modules. The track image of the light beam on the ground or on the object is captured by the camera and then the image is sent to the notebook computer for further processing and analysis. Using a developed signal-processing algorithm, our system can determine the object width and the distance between the object and the blind person through the calculation of the light line positions on the image. A series of feasibility tests of the developed blind guidance system were conducted. The experimental results show that the distance between the test object and the blind can be measured with a standard deviation of less than 8.5% within the range of 40 and 130 cm, while the test object width can be measured with a standard deviation of less than 4.5% within the range of 40 and 130 cm. The application potential of the designed system to the blind guidance can be expected.
Rail profile control using laser triangulation scanners
Boronahin, Ð. ńlexandr M.; Larionov, Daniil Yu.; Podgornaya, Liudmila N.; Shalymov, Roman V.; Filatov, Yuri V.; Bokhman, Evgueny D.
2016-11-01
Rail track geometric parameters measurement requires knowledge of left and right rail head location in each section. First of all displacement in transverse plane of rail head point located at a distance of 14 mm below the running surface, must be controlled [1]. It is carried out by detecting of each rail profile using triangulation laser scanners. Optical image recognition is carried out successfully in the laboratory, approaches used for this purpose are widely known. However, laser scanners operation has several features on railways leading to necessity of traditional approaches adaptation for solving these particular problems. The most significant problem is images noisiness due to the solar flashes and the effect of "Moon path" on the smooth rail surface. Using of optical filters gives inadequate result, because scanner laser diodes radiation frequency varies with temperature changes that forbid the use of narrow-band filters. Consideration of these features requires additional constructive and algorithmic solutions, including involvement of information from other sensors of the system. The specific usage of optical scanners for rail profiles control is the subject of the paper.
Research on Image processing in laser triangulation system
Energy Technology Data Exchange (ETDEWEB)
Liu Kai; Wang Qianqian; Wang Yang; Liu Chenrui, E-mail: qqwang@bit.edu.cn [School of Optoelectronics, Beijing Institute of Technology, 100081 Beijing (China)
2011-02-01
Laser Triangulation Ranging is a kind of displacement distance measurement method which is based on the principle of optical triangulation using laser as the light source. It is superior in simple structure, high-speed, high-accuracy, anti-jamming capability and adaptability laser triangulation ranging. Therefore it is widely used in various fields such as industrial production, road test, three-dimensional face detection, and so on. In current study the features of the spot images achieved by CCD in laser triangulation system were analyzed, and the appropriate algorithms for spot images were discussed. Experimental results showed that the precision and stability of the spot location were enhanced significantly after applying these image processing algorithms.
Reconstructing Surface Triangulations by Their Intersection Matrices 26 September 2014
2015-01-01
The intersection matrix of a simplicial complex has entries equal to the rank of the intersecction of its facets. We prove that this matrix is enough to define up to isomorphism a triangulation of a surface.
Position and orientation inference via on-board triangulation.
Advani, Madhu; Weile, Daniel S
2017-01-01
This work proposes a new approach to determine the spatial location and orientation of an object using measurements performed on the object itself. The on-board triangulation algorithm we outline could be implemented in lieu of, or in addition to, well-known alternatives such as Global Positioning System (GPS) or standard triangulation, since both of these correspond to significantly different geometric pictures and necessitate different hardware and algorithms. We motivate the theory by describing situations in which on-board triangulation would be useful and even preferable to standard methods. The on-board triangulation algorithm we outline involves utilizing dumb beacons which broadcast omnidirectional single frequency radio waves, and smart antenna arrays on the object itself to infer the direction of the beacon signals, which may be used for onboard calculation of the position and orientation of the object. Numerical examples demonstrate the utility of the method and its noise tolerance.
Aerial Triangulation Close-range Images with Dual Quaternion
Directory of Open Access Journals (Sweden)
SHENG Qinghong
2015-05-01
Full Text Available A new method for the aerial triangulation of close-range images based on dual quaternion is presented. Using dual quaternion to represent the spiral screw motion of the beam in the space, the real part of dual quaternion represents the angular elements of all the beams in the close-range area networks, the real part and the dual part of dual quaternion represents the line elements corporately. Finally, an aerial triangulation adjustment model based on dual quaternion is established, and the elements of interior orientation and exterior orientation and the object coordinates of the ground points are calculated. Real images and large attitude angle simulated images are selected to run the experiments of aerial triangulation. The experimental results show that the new method for the aerial triangulation of close-range images based on dual quaternion can obtain higher accuracy.
Dextran: A promising macromolecular drug carrier
Directory of Open Access Journals (Sweden)
Dhaneshwar Suneela
2006-01-01
Full Text Available Over the past three decades intensive efforts have been made to design novel systems able to deliver the drug more effectively to the target site. The ongoing intense search for novel and innovative drug delivery systems is predominantly a consequence of the well-established fact that the conventional dosage forms are not sufficiently effective in conveying the drug compound to its site of action and once in the target area, in releasing the active agent over a desired period of time. The potential use of macromolecular prodrugs as a means of achieving targeted drug delivery has attracted considerable interest in recent years. Macromolecules such as antibodies, lipoproteins, lectins, proteins, polypeptides, polysaccharides, natural as well as synthetic polymers offer potential applicabilities as high molecular weight carriers for various therapeutically active compounds. Dextrans serve as one of the most promising macromolecular carrier candidates for a wide variety of therapeutic agents due to their excellent physico-chemical properties and physiological acceptance. The present contribution attempts to review various features of the dextran carrier like its source, structural and physico-chemical characteristics, pharmacokinetic fate and its applications as macromolecular carrier with special emphasis on dextran prodrugs.
From recollement of triangulated categories to recollement of abelian categories
Institute of Scientific and Technical Information of China (English)
无
2010-01-01
In this paper,we prove that if a triangulated category D admits a recollement relative to triangulated categories D’ and D″,then the abelian category D/T admits a recollement relative to abelian categories D’/i(T) and D″/j(T) where T is a cluster tilting subcategory of D and satisfies i i (T) T,j j (T) T.
Yet another method for triangulation and contouring for automated cartography
De Floriani, L.; Falcidieno, B.; Nasy, G.; Pienovi, C.
1982-01-01
An algorithm is presented for hierarchical subdivision of a set of three-dimensional surface observations. The data structure used for obtaining the desired triangulation is also singularly appropriate for extracting contours. Some examples are presented, and the results obtained are compared with those given by Delaunay triangulation. The data points selected by the algorithm provide a better approximation to the desired surface than do randomly selected points.
Mesh Generation via Local Bisection Refinement of Triangulated Grids
2015-06-01
tb [Maubach 1995, Theorem 5.1]. This is exploited in the recursive algorithm RefineTriangle (Algorithm 2) to com- patibly refine a given triangle; the... recursion depth of RefineTriangle is bounded by the maximum level of refinement in T [Maubach 1995]. RefineTriangle calls itself repeatedly on a... sequence of triangles until a compatibly divisible triangle is found. This sequence of triangles is then bisected in reverse order to preserve
Algebraic Error Based Triangulation and Metric of Lines.
Wu, Fuchao; Zhang, Ming; Wang, Guanghui; Hu, Zhanyi
2015-01-01
Line triangulation, a classical geometric problem in computer vision, is to determine the 3D coordinates of a line based on its 2D image projections from more than two views of cameras with known projection matrices. Compared to point features, line segments are more robust to matching errors, occlusions, and image uncertainties. In addition to line triangulation, a better metric is needed to evaluate 3D errors of line triangulation. In this paper, the line triangulation problem is investigated by using the Lagrange multipliers theory. The main contributions include: (i) Based on the Lagrange multipliers theory, a formula to compute the Plücker correction is provided, and from the formula, a new linear algorithm, LINa, is proposed for line triangulation; (ii) two optimal algorithms, OPTa-I and OPTa-II, are proposed by minimizing the algebraic error; and (iii) two metrics on 3D line space, the orthogonal metric and the quasi-Riemannian metric, are introduced for the evaluation of line triangulations. Extensive experiments on synthetic data and real images are carried out to validate and demonstrate the effectiveness of the proposed algorithms.
Stereo Matching Algorithm Based on 2D Delaunay Triangulation
Directory of Open Access Journals (Sweden)
Xue-he Zhang
2015-01-01
Full Text Available To fulfill the applications on robot vision, the commonly used stereo matching method for depth estimation is supposed to be efficient in terms of running speed and disparity accuracy. Based on this requirement, Delaunay-based stereo matching method is proposed to achieve the aforementioned standards in this paper. First, a Canny edge operator is used to detect the edge points of an image as supporting points. Those points are then processed using a Delaunay triangulation algorithm to divide the whole image into a series of linked triangular facets. A proposed module composed of these facets performs a rude estimation of image disparity. According to the triangular property of shared vertices, the estimated disparity is then refined to generate the disparity map. The method is tested on Middlebury stereo pairs. The running time of the proposed method is about 1 s and the matching accuracy is 93%. Experimental results show that the proposed method improves both running speed and disparity accuracy, which forms a steady foundation and good application prospect for a robot’s path planning system with stereo camera devices.
Numerical Conformal Mapping Using Cross-Ratios and Delaunay Triangulation
Driscoll, Tobin A.; Vavasis, Stephen A.
1996-01-01
We propose a new algorithm for computing the Riemann mapping of the unit disk to a polygon, also known as the Schwarz-Christoffel transformation. The new algorithm, CRDT, is based on cross-ratios of the prevertices, and also on cross-ratios of quadrilaterals in a Delaunay triangulation of the polygon. The CRDT algorithm produces an accurate representation of the Riemann mapping even in the presence of arbitrary long, thin regions in the polygon, unlike any previous conformal mapping algorithm. We believe that CRDT can never fail to converge to the correct Riemann mapping, but the correctness and convergence proof depend on conjectures that we have so far not been able to prove. We demonstrate convergence with computational experiments. The Riemann mapping has applications to problems in two-dimensional potential theory and to finite-difference mesh generation. We use CRDT to produce a mapping and solve a boundary value problem on long, thin regions for which no other algorithm can solve these problems.
TRIANGULATION OF THE INTERSTELLAR MAGNETIC FIELD
Energy Technology Data Exchange (ETDEWEB)
Schwadron, N. A.; Moebius, E. [University of New Hampshire, Durham, NH 03824 (United States); Richardson, J. D. [Massachusetts Institute of Technology, Cambridge, MA 02139 (United States); Burlaga, L. F. [Goddard Space Flight Center, Greenbelt, MD 20771 (United States); McComas, D. J. [Southwest Research Institute, San Antonio, TX 78228 (United States)
2015-11-01
Determining the direction of the local interstellar magnetic field (LISMF) is important for understanding the heliosphere’s global structure, the properties of the interstellar medium, and the propagation of cosmic rays in the local galactic medium. Measurements of interstellar neutral atoms by Ulysses for He and by SOHO/SWAN for H provided some of the first observational insights into the LISMF direction. Because secondary neutral H is partially deflected by the interstellar flow in the outer heliosheath and this deflection is influenced by the LISMF, the relative deflection of H versus He provides a plane—the so-called B–V plane in which the LISMF direction should lie. Interstellar Boundary Explorer (IBEX) subsequently discovered a ribbon, the center of which is conjectured to be the LISMF direction. The most recent He velocity measurements from IBEX and those from Ulysses yield a B–V plane with uncertainty limits that contain the centers of the IBEX ribbon at 0.7–2.7 keV. The possibility that Voyager 1 has moved into the outer heliosheath now suggests that Voyager 1's direct observations provide another independent determination of the LISMF. We show that LISMF direction measured by Voyager 1 is >40° off from the IBEX ribbon center and the B–V plane. Taking into account the temporal gradient of the field direction measured by Voyager 1, we extrapolate to a field direction that passes directly through the IBEX ribbon center (0.7–2.7 keV) and the B–V plane, allowing us to triangulate the LISMF direction and estimate the gradient scale size of the magnetic field.
Large-volume protein crystal growth for neutron macromolecular crystallography.
Ng, Joseph D; Baird, James K; Coates, Leighton; Garcia-Ruiz, Juan M; Hodge, Teresa A; Huang, Sijay
2015-04-01
Neutron macromolecular crystallography (NMC) is the prevailing method for the accurate determination of the positions of H atoms in macromolecules. As neutron sources are becoming more available to general users, finding means to optimize the growth of protein crystals to sizes suitable for NMC is extremely important. Historically, much has been learned about growing crystals for X-ray diffraction. However, owing to new-generation synchrotron X-ray facilities and sensitive detectors, protein crystal sizes as small as in the nano-range have become adequate for structure determination, lessening the necessity to grow large crystals. Here, some of the approaches, techniques and considerations for the growth of crystals to significant dimensions that are now relevant to NMC are revisited. These include experimental strategies utilizing solubility diagrams, ripening effects, classical crystallization techniques, microgravity and theoretical considerations.
Laser triangulation measurements of scoliotic spine curvatures.
Čelan, Dušan; Jesenšek Papež, Breda; Poredoš, Primož; Možina, Janez
2015-01-01
The main purpose of this research was to develop a new method for differentiating between scoliotic and healthy subjects by analysing the curvatures of their spines in the cranio-caudal view. The study included 247 subjects with physiological curvatures of the spine and 28 subjects with clinically confirmed scoliosis. The curvature of the spine was determined by a computer analysis of the surface of the back, measured with a non-invasive, 3D, laser-triangulation system. The determined spinal curve was represented in the transversal plane, which is perpendicular to the line segment that was defined by the initial point and the end point of the spinal curve. This was achieved using a rotation matrix. The distances between the extreme points in the antero-posterior (AP) and left-right (LR) views were calculated in relation to the length of the spine as well as the quotient of these two values LR/AP. All the measured parameters were compared between the scoliotic and control groups using the Student's t-Test in case of normal data and Kruskal-Wallis test in case of non-normal data. Besides, a comprehensive diagram representing the distances between the extreme points in the AP and LR views was introduced, which clearly demonstrated the direction and the size of the thoracic and lumbar spinal curvatures for each individual subject. While the distances between the extreme points of the spine in the AP view were found to differ only slightly between the groups (p = 0.1), the distances between the LR extreme points were found to be significantly greater in the scoliosis group, compared to the control group (p < 0.001). The quotient LR/AP was statistically significantly different in both groups (p < 0.001). The main innovation of the presented method is the ability to differentiate a scoliotic subject from a healthy subject by assessing the curvature of the spine in the cranio-caudal view. Therefore, the proposed method could be useful for human posture
Smoothing techniques for macromolecular global optimization
Energy Technology Data Exchange (ETDEWEB)
More, J.J.; Wu, Zhijun
1995-09-01
We study global optimization problems that arise in macromolecular modeling, and the solution of these problems via continuation and smoothing. Our results unify and extend the theory associated with the use of the Gaussian transform for smoothing. We show that the, Gaussian transform can be viewed as a special case of a generalized transform and that these generalized transforms share many of the properties of the Gaussian transform. We also show that the smoothing behavior of the generalized transform can be studied in terms of the Fourier transform and that these results indicate that the Gaussian transform has superior smoothing properties.
Algorithms for Sampling 3-Orientations of Planar Triangulations
Miracle, Sarah; Streib, Amanda Pascoe; Tetali, Prasad
2012-01-01
Given a planar triangulation, a 3-orientation is an orientation of the internal edges so all internal vertices have out-degree three. Each 3-orientation gives rise to a unique edge coloring known as a Schnyder wood that has proven powerful for various computing and combinatorics applications. We consider natural Markov chains for sampling uniformly from the set of 3-orientations. First, we study a "triangle-reversing" chain on the space of 3-orientations of a fixed triangulation that reverses the orientation of the edges around a triangle in each move. It was shown previously that this chain connects the state space and we show that (i) when restricted to planar triangulations of maximum degree six, the Markov chain is rapidly mixing, and (ii) there exists a triangulation with high degree on which this Markov chain mixes slowly. Next, we consider an "edge-flipping" chain on the larger state space consisting of 3-orientations of all planar triangulations on a fixed number of vertices. It was also shown previou...
Measurement Uncertainty of Microscopic Laser Triangulation on Technical Surfaces.
Mueller, Thomas; Poesch, Andreas; Reithmeier, Eduard
2015-12-01
Laser triangulation is widely used to measure three-dimensional structure of surfaces. The technique is suitable for macroscopic and microscopic surface measurements. In this paper, the measurement uncertainty of laser triangulation is investigated on technical surfaces for microscopic measurement applications. Properties of technical surfaces are, for example, reflectivity, surface roughness, and the presence of scratches and pores. These properties are more influential in the microscopic laser triangulation than in the macroscopic one. In the Introduction section of this paper, the measurement uncertainty of laser triangulation is experimentally investigated for 13 different specimens. The measurements were carried out with and without a laser speckle reducer. In the Materials and Methods section of this paper, the surfaces of the 13 specimens are characterized in order to be able to find correlations between the surface properties and the measurement uncertainty. The last section of this paper describes simulations of the measurement uncertainty, which allow for the calculation of the measurement uncertainty with only one source of uncertainty present. The considerations in this paper allow for the assessment of the measurement uncertainty of laser triangulation on any technical surface when some surface properties, such as roughness, are known.
Macromolecular recognition in the Protein Data Bank
Energy Technology Data Exchange (ETDEWEB)
Janin, Joël, E-mail: joel.janin@ibbmc.u-psud.fr [Laboratoire d’Enzymologie et de Biochimie Structurales, UPR9063, CNRS, 91198 Gif-sur-Yvette (France); Institut de Biochimie et Biologie Moléculaire et Cellulaire, UMR8619, Bâtiment 430, Université Paris-Sud, 91405 Orsay (France); Rodier, Francis [Laboratoire d’Enzymologie et de Biochimie Structurales, UPR9063, CNRS, 91198 Gif-sur-Yvette (France); Chakrabarti, Pinak [Department of Biochemistry, Bose Institute, P-1/12 CIT Scheme VIIM, Calcutta 700 054 (India); Bahadur, Ranjit P. [Institut de Biochimie et Biologie Moléculaire et Cellulaire, UMR8619, Bâtiment 430, Université Paris-Sud, 91405 Orsay (France); Department of Biochemistry, Bose Institute, P-1/12 CIT Scheme VIIM, Calcutta 700 054 (India); Laboratoire d’Enzymologie et de Biochimie Structurales, UPR9063, CNRS, 91198 Gif-sur-Yvette (France)
2007-01-01
X-ray structures in the PDB illustrate both the specific recognition of two polypeptide chains in protein–protein complexes and dimeric proteins and their nonspecific interaction at crystal contacts. Crystal structures deposited in the Protein Data Bank illustrate the diversity of biological macromolecular recognition: transient interactions in protein–protein and protein–DNA complexes and permanent assemblies in homodimeric proteins. The geometric and physical chemical properties of the macromolecular interfaces that may govern the stability and specificity of recognition are explored in complexes and homodimers compared with crystal-packing interactions. It is found that crystal-packing interfaces are usually much smaller; they bury fewer atoms and are less tightly packed than in specific assemblies. Standard-size interfaces burying 1200–2000 Å{sup 2} of protein surface occur in protease–inhibitor and antigen–antibody complexes that assemble with little or no conformation changes. Short-lived electron-transfer complexes have small interfaces; the larger size of the interfaces observed in complexes involved in signal transduction and homodimers correlates with the presence of conformation changes, often implicated in biological function. Results of the CAPRI (critical assessment of predicted interactions) blind prediction experiment show that docking algorithms efficiently and accurately predict the mode of assembly of proteins that do not change conformation when they associate. They perform less well in the presence of large conformation changes and the experiment stimulates the development of novel procedures that can handle such changes.
Rotation-Induced Macromolecular Spooling of DNA
Directory of Open Access Journals (Sweden)
Tyler N. Shendruk
2017-07-01
Full Text Available Genetic information is stored in a linear sequence of base pairs; however, thermal fluctuations and complex DNA conformations such as folds and loops make it challenging to order genomic material for in vitro analysis. In this work, we discover that rotation-induced macromolecular spooling of DNA around a rotating microwire can monotonically order genomic bases, overcoming this challenge. We use single-molecule fluorescence microscopy to directly visualize long DNA strands deforming and elongating in shear flow near a rotating microwire, in agreement with numerical simulations. While untethered DNA is observed to elongate substantially, in agreement with our theory and numerical simulations, strong extension of DNA becomes possible by introducing tethering. For the case of tethered polymers, we show that increasing the rotation rate can deterministically spool a substantial portion of the chain into a fully stretched, single-file conformation. When applied to DNA, the fraction of genetic information sequentially ordered on the microwire surface will increase with the contour length, despite the increased entropy. This ability to handle long strands of DNA is in contrast to modern DNA sample preparation technologies for sequencing and mapping, which are typically restricted to comparatively short strands, resulting in challenges in reconstructing the genome. Thus, in addition to discovering new rotation-induced macromolecular dynamics, this work inspires new approaches to handling genomic-length DNA strands.
Rotation-Induced Macromolecular Spooling of DNA
Shendruk, Tyler N.; Sean, David; Berard, Daniel J.; Wolf, Julian; Dragoman, Justin; Battat, Sophie; Slater, Gary W.; Leslie, Sabrina R.
2017-07-01
Genetic information is stored in a linear sequence of base pairs; however, thermal fluctuations and complex DNA conformations such as folds and loops make it challenging to order genomic material for in vitro analysis. In this work, we discover that rotation-induced macromolecular spooling of DNA around a rotating microwire can monotonically order genomic bases, overcoming this challenge. We use single-molecule fluorescence microscopy to directly visualize long DNA strands deforming and elongating in shear flow near a rotating microwire, in agreement with numerical simulations. While untethered DNA is observed to elongate substantially, in agreement with our theory and numerical simulations, strong extension of DNA becomes possible by introducing tethering. For the case of tethered polymers, we show that increasing the rotation rate can deterministically spool a substantial portion of the chain into a fully stretched, single-file conformation. When applied to DNA, the fraction of genetic information sequentially ordered on the microwire surface will increase with the contour length, despite the increased entropy. This ability to handle long strands of DNA is in contrast to modern DNA sample preparation technologies for sequencing and mapping, which are typically restricted to comparatively short strands, resulting in challenges in reconstructing the genome. Thus, in addition to discovering new rotation-induced macromolecular dynamics, this work inspires new approaches to handling genomic-length DNA strands.
Analysis of imaging for laser triangulation sensors under Scheimpflug rule.
Miks, Antonin; Novak, Jiri; Novak, Pavel
2013-07-29
In this work a detailed analysis of the problem of imaging of objects lying in the plane tilted with respect to the optical axis of the rotationally symmetrical optical system is performed by means of geometrical optics theory. It is shown that the fulfillment of the so called Scheimpflug condition (Scheimpflug rule) does not guarantee the sharp image of the object as it is usually declared because of the fact that due to the dependence of aberrations of real optical systems on the object distance the image becomes blurred. The f-number of a given optical system also varies with the object distance. It is shown the influence of above mentioned effects on the accuracy of the laser triangulation sensors measurements. A detailed analysis of laser triangulation sensors, based on geometrical optics theory, is performed and relations for the calculation of measurement errors and construction parameters of laser triangulation sensors are derived.
Moving sound source localization based on triangulation method
Miao, Feng; Yang, Diange; Wen, Junjie; Lian, Xiaomin
2016-12-01
This study develops a sound source localization method that extends traditional triangulation to moving sources. First, the possible sound source locating plane is scanned. Secondly, for each hypothetical source location in this possible plane, the Doppler effect is removed through the integration of sound pressure. Taking advantage of the de-Dopplerized signals, the moving time difference of arrival (MTDOA) is calculated, and the sound source is located based on triangulation. Thirdly, the estimated sound source location is compared to the original hypothetical location and the deviations are recorded. Because the real sound source location leads to zero deviation, the sound source can be finally located by minimizing the deviation matrix. Simulations have shown the superiority of MTDOA method over traditional triangulation in case of moving sound sources. The MTDOA method can be used to locate moving sound sources with as high resolution as DAMAS beamforming, as shown in the experiments, offering thus a new method for locating moving sound sources.
The role of macromolecular stability in desiccation tolerance
Wolkers, W.F.
1998-01-01
The work presented in this thesis concerns a study on the molecular interactions that play a role in the macromolecular stability of desiccation-tolerant higher plant organs. Fourier transform infrared microspectroscopy was used as the main experimental technique to assess macromolecular st
The role of macromolecular stability in desiccation tolerance.
Wolkers, W.
1998-01-01
The work presented in this thesis concerns a study on the molecular interactions that play a role in the macromolecular stability of desiccation-tolerant higher plant organs. Fourier transform infrared microspectroscopy was used as the main experimental technique to assess macromolecular structures
Degree-Regular Triangulations of Torus and Klein Bottle-Erratum
Indian Academy of Sciences (India)
Basudeb Datta; Ashish Kumar Upadhyay
2005-08-01
A triangulation of a connected closed surface is called weakly regular if the action of its automorphism group on its vertices is transitive. A triangulation of a connected closed surface is called degree-regular if each of its vertices have the same degree. Clearly, a weakly regular triangulation is degree-regular. In [8], Lutz has classified all the weakly regular triangulations on at most 15 vertices. In [5], Datta and Nilakantan have classified all the degree-regular triangulations of closed surfaces on at most 11 vertices. In this article, we have proved that any degree-regular triangulation of the torus is weakly regular. We have shown that there exists an -vertex degree-regular triangulation of the Klein bottle if and only if is a composite number ≥ 9. We have constructed two distinct -vertex weakly regular triangulations of the torus for each ≥ 12 and a (4+2)-vertex weakly regular triangulation of the Klein bottle for each ≥ 2. For 12 ≤ ≤ 15, we have classified all the -vertex degree-regular triangulations of the torus and the Klein bottle. There are exactly 19 such triangulations, 12 of which are triangulations of the torus and remaining 7 are triangulations of the Klein bottle. Among the last 7, only one is weakly regular.
Redesign of a conformal boundary recovery algorithm for 3D Delaunay triangulation
Institute of Scientific and Technical Information of China (English)
CHEN Jian-jun; ZHENG Yao
2006-01-01
Boundary recovery is one of the main obstacles in applying the Delaunay criterion to mesh generation. A standard resolution is to add Steiner points directly at the intersection positions between missing boundaries and triangulations. We redesign the algorithm with the aid of some new concepts, data structures and operations, which make its implementation routine.Furthermore, all possible intersection cases and their solutions are presented, some of which are seldom discussed in the literature. Finally, numerical results are presented to evaluate the performance of the new algorithm.
An overview of the stereo correlation and triangulation formulations used in DICe.
Energy Technology Data Exchange (ETDEWEB)
Turner, Daniel Z. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)
2017-02-01
This document provides a detailed overview of the stereo correlation algorithm and triangulation formulation used in the Digital Image Correlation Engine (DICe) to triangulate three dimensional motion in space given the image coordinates and camera calibration parameters.
The Use of Triangulation Methods in Qualitative Educational Research
Oliver-Hoyo, Maria; Allen, DeeDee
2006-01-01
Triangulation involves the careful reviewing of data collected through different methods in order to achieve a more accurate and valid estimate of qualitative results for a particular construct. This paper describes how we used three qualitative methods of data collection to study attitudes of students toward graphing, hands-on activities, and…
Methodological triangulation of the students' use of recorded lectures
Gorissen, Pierre; Bruggen, Jan van; Jochems, Wim
2013-01-01
A lot of research into the use of recorded lectures has been done by using surveys or interviews. We will show that triangulation of multiple data sources is needed. We will discuss how students use recorded lectures according to their self-report and what actual usage of the recorded lectures can b
Mutating loops and 2-cycles in 2-CY triangulated categories
Bertani-Økland, Marco Angel
2010-01-01
We derive an algorithm for mutating quivers of 2-CY tilted algebras that have loops and 2-cycles, under certain specific conditions. Further, we give the classification of the 2-CY tilted algebras coming from standard algebraic 2-CY triangulated categories with a finite number of indecomposables. These form a class of algebras that satisfy the setup for our mutation algorithm.
A Simple Quality Triangulation Algorithm for Complex Geometries
This paper presents a new and simple algorithm for quality triangulation in complex geometries. The proposed algorithm is based on an initial equilateral triangle mesh covering the whole domain. The mesh nodes close to the boundary edges satisfy the so-called non-encroaching criterion: the distance ...
Analysing students' use of recorded lectures through methodological triangulation
Gorissen, Pierre; Van Bruggen, Jan; Jochems, Wim
2012-01-01
Gorissen, P., Van Bruggen, J., & Jochems, W. M. G. (2012). Analysing students' use of recorded lectures through methodological triangulation. In L. Uden, E. S. Corchado Rodríquez, J. F. De Paz Santana, & F. De la Prieta (Eds.), Workshop on Learning Technology in Cloud (LTEC’12) (pp. 145-156). Heidel
Ideal Triangulations of Pseudo-Anosov Mapping Tori
Agol, Ian
2010-01-01
We show how to construct an ideal triangulation of a mapping torus of a pseudo-Anosov map punctured along the singular fibers. This gives rise to a new conjugacy invariant of mapping classes, and a new proof of a theorem of Farb-Leininger-Margalit. The approach in this paper is based on ideas of Hamenstadt.
A Triangulation Method for Identifying Hydrostratigraphic Locations of Well Screens
Energy Technology Data Exchange (ETDEWEB)
Whiteside, T. S. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL). Radiological Performance Assessment
2015-01-31
A method to identify the hydrostratigraphic location of well screens was developed using triangulation with known locations. This method was applied to all of the monitor wells being used to develop the new GSA groundwater model. Results from this method are closely aligned with those from an alternate method which uses a mesh surface.
Internet information triangulation: Design theory and prototype evaluation
Wijnhoven, Alphonsus B.J.M.; Brinkhuis, Michel
2014-01-01
Many discussions exist regarding the credibility of information on the Internet. Similar discussions happen on the interpretation of social scientific research data, for which information triangulation has been proposed as a useful method. In this article, we explore a design theory—consisting of a
Internet information triangulation: Design theory and prototype evaluation
Wijnhoven, Fons; Brinkhuis, Michel
2014-01-01
Many discussions exist regarding the credibility of information on the Internet. Similar discussions happen on the interpretation of social scientific research data, for which information triangulation has been proposed as a useful method. In this article, we explore a design theory—consisting of a
The Use of Triangulation Methods in Qualitative Educational Research
Oliver-Hoyo, Maria; Allen, DeeDee
2006-01-01
Triangulation involves the careful reviewing of data collected through different methods in order to achieve a more accurate and valid estimate of qualitative results for a particular construct. This paper describes how we used three qualitative methods of data collection to study attitudes of students toward graphing, hands-on activities, and…
Chow groups and intersection products for tensor triangulated categories
Klein, S.A.
2014-01-01
This thesis deals with a generalization of an important family of invariants from algebraic geometry (the Chow groups of an algebraic variety) to the setting of tensor triangulated categories. It is shown that these tensor triangular Chow groups recover the usual notion of Chow groups of an
Quantum Computing in Decoherence-Free Subspace Constructed by Triangulation
Directory of Open Access Journals (Sweden)
Qiao Bi
2010-01-01
Full Text Available A formalism for quantum computing in decoherence-free subspaces is presented. The constructed subspaces are partial triangulated to an index related to environment. The quantum states in the subspaces are just projected states which are ruled by a subdynamic kinetic equation. These projected states can be used to perform ideal quantum logical operations without decoherence.
Satisfying states of triangulations of a convex n-gon
Jiménez, Andrea; Loebl, Martin
2009-01-01
In this work we count the number of satisfying states of triangulations of a convex n-gon using the transfer matrix method. We show an exponential (in n) lower bound. We also give the exact formula for the number of satisfying states of a strip of triangles.
Fosco, Gregory M.; Grych, John H.
2010-01-01
Although triangulation into parental conflict is a risk factor for child and adolescent maladjustment, little is known about how triangulation affects adolescents' functioning or the factors that lead children to be drawn into parental disagreements. This prospective study examined the relations between triangulation, appraisals of conflict, and…
Fosco, Gregory M.; Grych, John H.
2010-01-01
Although triangulation into parental conflict is a risk factor for child and adolescent maladjustment, little is known about how triangulation affects adolescents' functioning or the factors that lead children to be drawn into parental disagreements. This prospective study examined the relations between triangulation, appraisals of conflict, and…
3DEM Loupe: Analysis of macromolecular dynamics using structures from electron microscopy.
Nogales-Cadenas, R; Jonic, S; Tama, F; Arteni, A A; Tabas-Madrid, D; Vázquez, M; Pascual-Montano, A; Sorzano, C O S
2013-07-01
Electron microscopy (EM) provides access to structural information of macromolecular complexes in the 3-20 Å resolution range. Normal mode analysis has been extensively used with atomic resolution structures and successfully applied to EM structures. The major application of normal modes is the identification of possible conformational changes in proteins. The analysis can throw light on the mechanism following ligand binding, protein-protein interactions, channel opening and other functional macromolecular movements. In this article, we present a new web server, 3DEM Loupe, which allows normal mode analysis of any uploaded EM volume using a user-friendly interface and an intuitive workflow. Results can be fully explored in 3D through animations and movies generated by the server. The application is freely available at http://3demloupe.cnb.csic.es.
Energy Technology Data Exchange (ETDEWEB)
Foadi, James [Diamond Light Source, Harwell Science and Innovation Campus, Didcot, Oxfordshire OX11 0DE (United Kingdom); Imperial College, London SW7 2AZ (United Kingdom); Aller, Pierre [Diamond Light Source, Harwell Science and Innovation Campus, Didcot, Oxfordshire OX11 0DE (United Kingdom); Alguel, Yilmaz; Cameron, Alex [Imperial College, London SW7 2AZ (United Kingdom); Axford, Danny; Owen, Robin L. [Diamond Light Source, Harwell Science and Innovation Campus, Didcot, Oxfordshire OX11 0DE (United Kingdom); Armour, Wes [Oxford e-Research Centre (OeRC), Keble Road, Oxford OX1 3QG (United Kingdom); Waterman, David G. [Research Complex at Harwell (RCaH), Harwell Science and Innovation Campus, Didcot, Oxfordshire OX11 0FA (United Kingdom); Iwata, So [Diamond Light Source, Harwell Science and Innovation Campus, Didcot, Oxfordshire OX11 0DE (United Kingdom); Imperial College, London SW7 2AZ (United Kingdom); Evans, Gwyndaf, E-mail: gwyndaf.evans@diamond.ac.uk [Diamond Light Source, Harwell Science and Innovation Campus, Didcot, Oxfordshire OX11 0DE (United Kingdom)
2013-08-01
A systematic approach to the scaling and merging of data from multiple crystals in macromolecular crystallography is introduced and explained. The availability of intense microbeam macromolecular crystallography beamlines at third-generation synchrotron sources has enabled data collection and structure solution from microcrystals of <10 µm in size. The increased likelihood of severe radiation damage where microcrystals or particularly sensitive crystals are used forces crystallographers to acquire large numbers of data sets from many crystals of the same protein structure. The associated analysis and merging of multi-crystal data is currently a manual and time-consuming step. Here, a computer program, BLEND, that has been written to assist with and automate many of the steps in this process is described. It is demonstrated how BLEND has successfully been used in the solution of a novel membrane protein.
Functional Sub-states by High-pressure Macromolecular Crystallography.
Dhaussy, Anne-Claire; Girard, Eric
2015-01-01
At the molecular level, high-pressure perturbation is of particular interest for biological studies as it allows trapping conformational substates. Moreover, within the context of high-pressure adaptation of deep-sea organisms, it allows to decipher the molecular determinants of piezophily. To provide an accurate description of structural changes produced by pressure in a macromolecular system, developments have been made to adapt macromolecular crystallography to high-pressure studies. The present chapter is an overview of results obtained so far using high-pressure macromolecular techniques, from nucleic acids to virus capsid through monomeric as well as multimeric proteins.
Sequential recovery of macromolecular components of the nucleolus.
Bai, Baoyan; Laiho, Marikki
2015-01-01
The nucleolus is involved in a number of cellular processes of importance to cell physiology and pathology, including cell stress responses and malignancies. Studies of macromolecular composition of the nucleolus depend critically on the efficient extraction and accurate quantification of all macromolecular components (e.g., DNA, RNA, and protein). We have developed a TRIzol-based method that efficiently and simultaneously isolates these three macromolecular constituents from the same sample of purified nucleoli. The recovered and solubilized protein can be accurately quantified by the bicinchoninic acid assay and assessed by polyacrylamide gel electrophoresis or by mass spectrometry. We have successfully applied this approach to extract and quantify the responses of all three macromolecular components in nucleoli after drug treatments of HeLa cells, and conducted RNA-Seq analysis of the nucleolar RNA.
A Compact X-Ray System for Macromolecular Crystallography. 5
Gubarev, Mikhail; Ciszak, Ewa; Ponomarev, Igor; Joy, Marshall
2000-01-01
We describe the design and performance of a high flux x-ray system for macromolecular crystallography that combines a microfocus x-ray generator (40 gm FWHM spot size at a power level of 46.5Watts) and a 5.5 mm focal distance polycapillary optic. The Cu K(sub alpha) X-ray flux produced by this optimized system is 7.0 times above the X-ray flux previously reported. The X-ray flux from the microfocus system is also 3.2 times higher than that produced by the rotating anode generator equipped with a long focal distance graded multilayer monochromator (Green optic; CMF24-48-Cu6) and 30% less than that produced by the rotating anode generator with the newest design of graded multilayer monochromator (Blue optic; CMF12-38-Cu6). Both rotating anode generators operate at a power level of 5000 Watts, dissipating more than 100 times the power of our microfocus x-ray system. Diffraction data collected from small test crystals are of high quality. For example, 42,540 reflections collected at ambient temperature from a lysozyme crystal yielded R(sub sym) 5.0% for the data extending to 1.7A, and 4.8% for the complete set of data to 1.85A. The amplitudes of the reflections were used to calculate difference electron density maps that revealed positions of structurally important ions and water molecules in the crystal of lysozyme using the phases calculated from the protein model.
A Compact X-Ray System for Macromolecular Crystallography
Gubarev, Mikhail; Ciszak, Ewa; Ponomarev, Igor; Gibson, Walter; Joy, Marshall
2000-01-01
We describe the design and performance of a high flux x-ray system for a macromolecular crystallography that combines a microfocus x-ray generator (40 micrometer full width at half maximum spot size at a power level of 46.5 W) and a collimating polycapillary optic. The Cu Ka lpha x-ray flux produced by this optimized system through a 500,um diam orifice is 7.0 times greater than the x-ray flux previously reported by Gubarev et al. [M. Gubarev et al., J. Appl. Crystallogr. 33, 882 (2000)]. The x-ray flux from the microfocus system is also 2.6 times higher than that produced by a rotating anode generator equipped with a graded multilayer monochromator (green optic, Osmic Inc. CMF24-48-Cu6) and 40% less than that produced by a rotating anode generator with the newest design of graded multilayer monochromator (blue optic, Osmic, Inc. CMF12-38-Cu6). Both rotating anode generators operate at a power level of 5000 W, dissipating more than 100 times the power of our microfocus x-ray system. Diffraction data collected from small test crystals are of high quality. For example, 42 540 reflections collected at ambient temperature from a lysozyme crystal yielded R(sub sym)=5.0% for data extending to 1.70 A, and 4.8% for the complete set of data to 1.85 A. The amplitudes of the observed reflections were used to calculate difference electron density maps that revealed positions of structurally important ions and water molecules in the crystal of lysozyme using the phases calculated from the protein model.
Genus dependence of the number of (non-)orientable surface triangulations
Krüger, Benedikt; Mecke, Klaus
2016-04-01
Topological triangulations of orientable and nonorientable surfaces with arbitrary genus have important applications in quantum geometry, graph theory and statistical physics. However, until now, only the asymptotics for 2-spheres have been known analytically, and exact counts of triangulations are only available for both small genera and triangulations. We apply the Wang-Landau algorithm to calculate the number N (m ,h ) of triangulations for several orders of magnitude in system size m and type h (equals genus in orientable triangulations). We verify that the limit of the entropy density of triangulations is independent of genus and orientability and are able to determine the next-to-leading-order and the next-to-next-to-leading-order terms. We conjecture for the number of surface triangulations the asymptotic behavior N (m ,h )→(170.4 ±15.1 )hm-2 (h -1 )/5(256/27) m /2, which might guide a mathematician's proof for the exact asymptotics.
Refining a triangulation of a planar straight-line graph to eliminate large angles
Energy Technology Data Exchange (ETDEWEB)
Mitchell, S.A.
1993-05-13
Triangulations without large angles have a number of applications in numerical analysis and computer graphics. In particular, the convergence of a finite element calculation depends on the largest angle of the triangulation. Also, the running time of a finite element calculation is dependent on the triangulation size, so having a triangulation with few Steiner points is also important. Bern, Dobkin and Eppstein pose as an open problem the existence of an algorithm to triangulate a planar straight-line graph (PSLG) without large angles using a polynomial number of Steiner points. We solve this problem by showing that any PSLG with {upsilon} vertices can be triangulated with no angle larger than 7{pi}/8 by adding O({upsilon}{sup 2}log {upsilon}) Steiner points in O({upsilon}{sup 2} log{sup 2} {upsilon}) time. We first triangulate the PSLG with an arbitrary constrained triangulation and then refine that triangulation by adding additional vertices and edges. Some PSLGs require {Omega}({upsilon}{sup 2}) Steiner points in any triangulation achieving any largest angle bound less than {pi}. Hence the number of Steiner points added by our algorithm is within a log {upsilon} factor of worst case optimal. We note that our refinement algorithm works on arbitrary triangulations: Given any triangulation, we show how to refine it so that no angle is larger than 7{pi}/8. Our construction adds O(nm+nplog m) vertices and runs in time O(nm+nplog m) log(m+ p)), where n is the number of edges, m is one plus the number of obtuse angles, and p is one plus the number of holes and interior vertices in the original triangulation. A previously considered problem is refining a constrained triangulation of a simple polygon, where p = 1. For this problem we add O({upsilon}{sup 2}) Steiner points, which is within a constant factor of worst case optimal.
An upper limit for macromolecular crowding effects
Directory of Open Access Journals (Sweden)
Miklos Andrew C
2011-05-01
Full Text Available Abstract Background Solutions containing high macromolecule concentrations are predicted to affect a number of protein properties compared to those properties in dilute solution. In cells, these macromolecular crowders have a large range of sizes and can occupy 30% or more of the available volume. We chose to study the stability and ps-ns internal dynamics of a globular protein whose radius is ~2 nm when crowded by a synthetic microgel composed of poly(N-isopropylacrylamide-co-acrylic acid with particle radii of ~300 nm. Results Our studies revealed no change in protein rotational or ps-ns backbone dynamics and only mild (~0.5 kcal/mol at 37°C, pH 5.4 stabilization at a volume occupancy of 70%, which approaches the occupancy of closely packing spheres. The lack of change in rotational dynamics indicates the absence of strong crowder-protein interactions. Conclusions Our observations are explained by the large size discrepancy between the protein and crowders and by the internal structure of the microgels, which provide interstitial spaces and internal pores where the protein can exist in a dilute solution-like environment. In summary, microgels that interact weakly with proteins do not strongly influence protein dynamics or stability because these large microgels constitute an upper size limit on crowding effects.
Macromolecular components of tomato fruit pectin.
Fishman, M L; Gross, K C; Gillespie, D T; Sondey, S M
1989-10-01
Chelate and alkaline-soluble pectin extracted from cell walls of pericarp tissue from mature green, turning, and red ripe (Lycopersicon esculentum Mill.) fruit (cv. Rutgers), were studied by high-performance size-exclusion chromatography. Computer-aided curve fitting of the chromatograms to a series of Gaussian-shaped components revealed that pectin from all fractions was composed of a linear combination of five macromolecular-sized species. The relative sizes of these macromolecules as obtained from their radii of gyration were 1:2:4:8:16. Dialysis against 0.05 M NaCl induced partial dissociation of the biopolymers. Apparently, the weight fraction of smaller sized species increased at the expense of larger ones. Also, the dissociation produced low-molecular-weight fragments. Behavior in the presence of 0.05 M NaCl led to the conclusion that cell wall pectin acted as if it were an aggregated mosaic, held together at least partially through noncovalent interactions.
The solvent component of macromolecular crystals
Energy Technology Data Exchange (ETDEWEB)
Weichenberger, Christian X. [European Academy of Bozen/Bolzano (EURAC), Viale Druso 1, Bozen/Bolzano, I-39100 Südtirol/Alto Adige (Italy); Afonine, Pavel V. [Lawrence Berkeley National Laboratory (LBNL), 1 Cyclotron Road, Mail Stop 64R0121, Berkeley, CA 94720 (United States); Kantardjieff, Katherine [California State University, San Marcos, CA 92078 (United States); Rupp, Bernhard, E-mail: br@hofkristallamt.org [k.-k. Hofkristallamt, 991 Audrey Place, Vista, CA 92084 (United States); Medical University of Innsbruck, Schöpfstrasse 41, A-6020 Innsbruck (Austria)
2015-04-30
On average, the mother liquor or solvent and its constituents occupy about 50% of a macromolecular crystal. Ordered as well as disordered solvent components need to be accurately accounted for in modelling and refinement, often with considerable complexity. The mother liquor from which a biomolecular crystal is grown will contain water, buffer molecules, native ligands and cofactors, crystallization precipitants and additives, various metal ions, and often small-molecule ligands or inhibitors. On average, about half the volume of a biomolecular crystal consists of this mother liquor, whose components form the disordered bulk solvent. Its scattering contributions can be exploited in initial phasing and must be included in crystal structure refinement as a bulk-solvent model. Concomitantly, distinct electron density originating from ordered solvent components must be correctly identified and represented as part of the atomic crystal structure model. Herein, are reviewed (i) probabilistic bulk-solvent content estimates, (ii) the use of bulk-solvent density modification in phase improvement, (iii) bulk-solvent models and refinement of bulk-solvent contributions and (iv) modelling and validation of ordered solvent constituents. A brief summary is provided of current tools for bulk-solvent analysis and refinement, as well as of modelling, refinement and analysis of ordered solvent components, including small-molecule ligands.
Experiences with systematic triangulation at the Global Environment Facility.
Carugi, Carlo
2016-04-01
Systematic triangulation may address common challenges in evaluation, such as the scarcity or unreliability of data, or the complexities of comparing and cross-checking evidence from diverse disciplines. Used to identify key evaluation findings, its application has proven to be effective in addressing the limitations encountered in country-level evaluation analysis conducted by the Independent Evaluation Office of the Global Environment Facility (GEF). These include the scarcity or unreliability of national statistics on environmental indicators and data series, especially in Least Developed Countries; challenges in evaluating the impacts of GEF projects; and inherent difficulties in defining the GEF portfolio of projects prior to the undertaking of the evaluation. In addition to responding to the need for further developing triangulation protocols, procedures and/or methodologies advocated by some authors, the approach offers a contribution to evaluation practice. This applies particularly to those evaluation units tasked with country-level evaluations in international organizations, facing similar constraints.
A new insertion sequence for incremental Delaunay triangulation
Institute of Scientific and Technical Information of China (English)
Jian-Fei Liu; Jin-Hui Yan; S.H.Lo
2013-01-01
Incremental algorithm is one of the most popular procedures for constructing Delaunay triangulations (DTs).However,the point insertion sequence has a great impact on the amount of work needed for the construction of DTs.It affects the time for both point location and structure update,and hence the overall computational time of the triangulation algorithm.In this paper,a simple deterministic insertion sequence is proposed based on the breadth-first-search on a Kd-tree with some minor modifications for better performance.Using parent nodes as search-hints,the proposed insertion sequence proves to be faster and more stable than the Hilbert curve order and biased randomized insertion order (BRIO),especially for non-uniform point distributions over a wide range of benchmark examples.
Quality Tetrahedral Mesh Smoothing via Boundary-Optimized Delaunay Triangulation.
Gao, Zhanheng; Yu, Zeyun; Holst, Michael
2012-12-01
Despite its great success in improving the quality of a tetrahedral mesh, the original optimal Delaunay triangulation (ODT) is designed to move only inner vertices and thus cannot handle input meshes containing "bad" triangles on boundaries. In the current work, we present an integrated approach called boundary-optimized Delaunay triangulation (B-ODT) to smooth (improve) a tetrahedral mesh. In our method, both inner and boundary vertices are repositioned by analytically minimizing the error between a paraboloid function and its piecewise linear interpolation over the neighborhood of each vertex. In addition to the guaranteed volume-preserving property, the proposed algorithm can be readily adapted to preserve sharp features in the original mesh. A number of experiments are included to demonstrate the performance of our method.
Detectability of active triangulation range finder: a solar irradiance approach.
Liu, Huizhe; Gao, Jason; Bui, Viet Phuong; Liu, Zhengtong; Lee, Kenneth Eng Kian; Peh, Li-Shiuan; Png, Ching Eng
2016-06-27
Active triangulation range finders are widely used in a variety of applications such as robotics and assistive technologies. The power of the laser source should be carefully selected in order to satisfy detectability and still remain eye-safe. In this paper, we present a systematic approach to assess the detectability of an active triangulation range finder in an outdoor environment. For the first time, we accurately quantify the background noise of a laser system due to solar irradiance by coupling the Perez all-weather sky model and ray tracing techniques. The model is validated with measurements with a modeling error of less than 14.0%. Being highly generic and sufficiently flexible, the proposed model serves as a guide to define a laser system for any geographical location and microclimate.
Scale-dependent homogeneity measures for causal dynamical triangulations
Cooperman, Joshua H
2014-01-01
I propose two scale-dependent measures of the homogeneity of the quantum geometry determined by an ensemble of causal triangulations. The first measure is volumetric, probing the growth of volume with graph geodesic distance. The second measure is spectral, probing the return probability of a random walk with diffusion time. Both of these measures, particularly the first, are closely related to those used to assess the homogeneity of our own universe on the basis of galaxy redshift surveys. I employ these measures to quantify the quantum spacetime homogeneity as well as the temporal evolution of quantum spatial homogeneity of ensembles of causal triangulations in the well-known physical phase. According to these measures, the quantum spacetime geometry exhibits some degree of inhomogeneity on sufficiently small scales and a high degree of homogeneity on sufficiently large scales. This inhomogeneity appears unrelated to the phenomenon of dynamical dimensional reduction. I also uncover evidence for power-law sc...
Evaluating habitat selection with radio-telemetry triangulation error
Samuel, M.D.; Kenow, K.P.
1992-01-01
Radio-telemetry triangulation errors result in the mislocation of animals and misclassification of habitat use. We present analytical methods that provide improved estimates of habitat use when misclassification probabilities can be determined. When misclassification probabilities cannot be determined, we use random subsamples from the error distribution of an estimated animal location to improve habitat use estimates. We conducted Monte Carlo simulations to evaluate the effects of this subsampling method, triangulation error, number of animal locations, habitat availability, and habitat complexity on bias and variation in habitat use estimates. Results for the subsampling method are illustrated using habitat selection by redhead ducks (Aythya americana ). We recommend the subsampling method with a minimum of 50 random points to reduce problems associated with habitat misclassification.
Optimizing 3D Triangulations to Recapture Sharp Edges
DEFF Research Database (Denmark)
Bærentzen, Jakob Andreas
2006-01-01
sharp edges. The energy is minimized using edge swapping, and this can be done either in a greedy fashion or using simulated annealing. The latter is more costly, but effectively avoids local minima. The method has been used on a number of models. Particularly good results have been obtained on digital......In this report, a technique for optimizing 3D triangulations is proposed. The method seeks to minimize an energy defined as a sum of energy terms for each edge in a triangle mesh. The main contribution is a novel per edge energy which strikes a balance between penalizing dihedral angle yet allowing...... terrain models. It is demonstrated how the method has been able to recapture sharp edges which are clearly present in the data but not reflected by the original triangulation of the elevation points....
Algorithm for Triangulating Visual Landmarks and Determining Their Covariance
2012-01-01
gyroscopes ........................................ 22 1 1. INTRODUCTION The work described in this report has to do with the problem of vision...IMUs. Because of the small magnitude of random Euler angle errors from even inexpensive gyroscopes , the presented algorithm for triangulation is...gyroscopes9. Silicon-Vibratory MEMs Tactical-grade IFOGs Aviation-Grade Spinning Mass Random gyro rate noise 1 hr/ 0.1 hr/ 0.002 hr/ Random
The Stabilization and Idempotent Completion of a Left Triangulated Category
Institute of Scientific and Technical Information of China (English)
Lin XIN; Yixin FU
2012-01-01
Let ((ψ),Ω,△) be a left triangulated category with a fully faithful endofunctor Ω.We show a triangle-equivalence (S((ψ)),(Ω),(△)) ≌ (S((ψ)),(Ω),(△)),where (S((ψ)),(Ω),(△)) denotes the stabilization of the idempotent completion of ((ψ),Ω,△) and (S((ψ)),(Ω),(△)) denotes the idempotent completion of the stabilization of ((ψ),Ω,△).
Parallel implementation of an algorithm for Delaunay triangulation
Merriam, Marshal L.
1992-01-01
The theory and practice of implementing Tanemura's algorithm for 3D Delaunay triangulation on Intel's Gamma prototype, a 128 processor MIMD computer, is described. Efficient implementation of Tanemura's algorithm on a conventional, vector processing supercomputer is problematic. It does not vectorize to any significant degree and requires indirect addressing. Efficient implementation on a parallel architecture is possible, however. Speeds in excess of 20 times a single processor Cray Y-MP are realized on 128 processors of the Intel Gamma prototype.
Random discrete Morse theory and a new library of triangulations
DEFF Research Database (Denmark)
Benedetti, Bruno; Lutz, Frank Hagen
2014-01-01
We introduce random discrete Morse theory as a computational scheme to measure the complexity of a triangulation. The idea is to try to quantify the frequency of discrete Morse matchings with few critical cells. Our measure will depend on the topology of the space, but also on how nicely the space......” for testing algorithms based on discrete Morse theory. We propose a new library containing more complicated (and thus more meaningful) test examples....
The transfer matrix in four-dimensional Causal Dynamical Triangulations
Görlich, Andrzej
2013-01-01
Causal Dynamical Triangulations is a background independent approach to quantum gravity. In this paper we introduce a phenomenological transfer matrix model, where at each time step a reduced set of quantum states is used. The states are solely characterized by the discretized spatial volume. Using Monte Carlo simulations we determine the effective transfer matrix elements and extract the effective action for the scale factor. In this framework no degrees of freedom are frozen, however, the obtained action agrees with the minisuperspace model.
Institute of Scientific and Technical Information of China (English)
王中辉; 闫浩文
2011-01-01
算法首先将离散点与约束边界点一起进行Delaunay三角剖分，形成初始Delaunay三角网，然后将约束边界上的各条约束线段通过局部更新依次嵌入已有的三角网，最后再删除多余的三角形，从而得到带内外边界约束的平面点集Delaunay三角剖分.%The algorithm first triangulates the scattered points together with the constrained points to form the initial Delaunay triangulation, then each constrained segment in the constrained boundaries is interpolated to the existent triangulation in turn through local updating,finally the redundant triangles are removed, so Delaunay triangulation of a 2-dimension scattered point set with inner and outer boundary constrains is generated.
Optical triangulation-based microtopographic inspection of surfaces.
Costa, Manuel F M
2012-01-01
The non-invasive inspection of surfaces is a major issue in a wide variety of industries and research laboratories. The vast and increasing range of surface types, tolerance requirements and measurement constraints demanded during the last decades represents a major research effort in the development of new methods, systems and metrological strategies. The discreet dimensional evaluation the rugometric characterization and the profilometric inspection seem to be insufficient in many instances. The full microtopographic inspection has became a common requirement. Among the different systems developed, optical methods have the most important role and among those triangulation-based ones have gained a major status thanks to their flexibility, reliability and robustness. In this communication we will provide a brief historical review on the development of optical triangulation application to the dimensional inspection of objects and surfaces and on the work done at the Microtopography Laboratory of the Physics Department of the University of Minho, Portugal, in the development of methods and systems of optical triangulation-based microtopographic inspection of surfaces.
Excerpt from Triangulations: Narrative Strategies for Navigating Latino Identity
Directory of Open Access Journals (Sweden)
David J. Vázquez
2011-12-01
Full Text Available Just as mariners use triangulation, mapping an imaginary triangle between two known positions and an unknown location, so, David J. Vázquez contends, Latino authors in late twentieth-century America employ the coordinates of familiar ideas of self to find their way to new, complex identities. Through this metaphor, Vázquez reveals how Latino autobiographical texts, written after the rise of cultural nationalism in the 1960s, challenge mainstream notions of individual identity and national belonging in the United States.In a traditional autobiographical work, the protagonist frequently opts out of his or her community. In the works that Vázquez analyzes in Triangulations, protagonists instead opt in to collective groups—often for the express political purpose of redefining that collective. Reading texts by authors such as Ernesto Galarza, Jesús Colón, Piri Thomas, Oscar “Zeta” Acosta, Judith Ortiz Cofer, John Rechy, Julia Alvarez, and Sandra Cisneros, Vázquez engages debates about the relationship between literature and social movements, the role of cultural nationalism in projects for social justice, the gender and sexual problematics of 1960s cultural nationalist groups, the possibilities for interethnic coalitions, and the interpretation of autobiography. In the process, Triangulations considers the potential for cultural nationalism as a productive force for aggrieved communities of color in their struggles for equality.
Namasivayam, Mayooran; Adji, Audrey; O'Rourke, Michael F
2016-02-01
Pulsatile blood pressure rises with age, especially in the aorta. The comparative role of forward and reflected pressure waves (FW and RW, respectively), determined by aortic flow triangulation has not previously been explored in a large clinical cohort. This study aimed to identify the role of FW and RW in the rise in aortic pulse pressure with age. For 879 outpatients, aortic pressure waveforms were generated using a validated generalized transfer function applied to radial pressure waves recorded using applanation tonometry. FW and RW were subsequently determined using aortic flow triangulation. Contributions of FW and RW to rise in aortic pulse pressure with age were determined using multivariate linear regression and product of coefficient mediation analysis, with adjustment for height, weight, heart rate, and mean arterial pressure. Comparisons were made by gender and before and after age 60. In subjects aged 60 and below, RW was an important contributor to pulsatile pressure elevation with age, but FW was non-contributory in either gender after multivariate correction. In subjects aged above 60, both FW and RW were significant and equal contributors in both genders. In a clinical setting, both FW and RW are important to pulsatile aortic blood pressure across the lifespan, but RW appears to have a more pronounced effect across all ages, whereas FW has less effect in younger persons. © American Journal of Hypertension, Ltd 2015. All rights reserved. For Permissions, please email: journals.permissions@oup.com.
Institute of Scientific and Technical Information of China (English)
FA WenZhe; XU Feng; JIN YaQiu
2009-01-01
Based on the statistics of the lunar cratered terrain, e.g., population, dimension and shape of craters, the terrain feature of cratered lunar surface is numerically generated. According to the Inhomogeneous distribution of the lunar surface slope, the triangulated irregular network (TIN) is employed to make the digital elevation of lunar surface model. The Kirchhoff approximation of surface scattering is then applied to simulation of lunar surface scattering. The synthetic aperture radar (SAR) image for compre-hensive cratered lunar surface is numerically generated using back projection (BP) algorithm of SAR Imaging. Making use of the digital elevation and Clementlne UVVIS data at Apollo 15 landing site as the ground truth, an SAR Image at Apollo 15 landing site Is simulated. The image simulation is verified using real SAR image and echoes statistics.
Performance Evaluation of Triangulation Based Range Sensors
Directory of Open Access Journals (Sweden)
Monica Bordegoni
2010-07-01
Full Text Available The performance of 2D digital imaging systems depends on several factors related with both optical and electronic processing. These concepts have originated standards, which have been conceived for photographic equipment and bi-dimensional scanning systems, and which have been aimed at estimating different parameters such as resolution, noise or dynamic range. Conversely, no standard test protocols currently exist for evaluating the corresponding performances of 3D imaging systems such as laser scanners or pattern projection range cameras. This paper is focused on investigating experimental processes for evaluating some critical parameters of 3D equipment, by extending the concepts defined by the ISO standards to the 3D domain. The experimental part of this work concerns the characterization of different range sensors through the extraction of their resolution, accuracy and uncertainty from sets of 3D data acquisitions of specifically designed test objects whose geometrical characteristics are known in advance. The major objective of this contribution is to suggest an easy characterization process for generating a reliable comparison between the performances of different range sensors and to check if a specific piece of equipment is compliant with the expected characteristics.
Triangulation Algorithm Based on Empty Convex Set Condition
Directory of Open Access Journals (Sweden)
Klyachin Vladimir Aleksandrovich
2015-11-01
Full Text Available The article is devoted to generalization of Delaunay triangulation. We suggest to consider empty condition for special convex sets. For given finite set P ⊂ Rn we shall say that empty condition for convex set B ⊂ Rn is fullfiled if P ∩ B = P ∩ ∂B. Let Φ = Φα, α ∈ A be a family of compact convex sets with non empty inner. Consider some nondegenerate simplex S ⊂ Rn with vertexes p0,...,pn. We define the girth set B(S ∈ Φ if qi ∈ ∂B(S, i = 0, 1, ..., n. We suppose that the family Φ has the property: for arbitrary nondegenerate simplex S there is only one the girth set B(S. We prove the following main result. Theorem 1. If the family Φ = Φα, α ∈ A of convex sets have the pointed above property then for the girth sets it is true: 1. The set B(S is uniquely determined by any simplex with vertexes on ∂B(S. 2. Let S1, S2 be two nondegenerate simplexes such that B(S1 ≠ B(S2. If the intersection B(S1 ∩ B(S2 is not empty, then the intersection of boundaries B(S1, B(S2 is (n − 2-dimensional convex surface, lying in some hyperplane. 3. If two simplexes S1 and S2 don’t intersect by inner points and have common (n − 1-dimensional face G and A, B are vertexes don’t belong to face G and vertex B of simplex B(S2 such that B ∉ B(S1 then B(S2 does not contain the vertex A of simplex S1. These statements allow us to define Φ-triangulation correctly by the following way. The given triangulation T of finite set P ⊂ Rn is called Φ-triangulation if for all simlex S ∈ T the girth set B(S ∈ Φ is empty. In the paper we give algorithm for construct Φ-triangulation arbitrary finite set P ⊂ Rn. Besides we describe examples of families Φ for which we prove the existence and uniqueness of girth set B(S for arbitrary nondegenerate simplex S.
Macromolecular Topography Leaps into the Digital Age
Lovelace, J.; Bellamy, H.; Snell, E. H.; Borgstahl, G.
2003-01-01
A low-cost, real-time digital topography system is under development which will replace x-ray film and nuclear emulsion plates. The imaging system is based on an inexpensive surveillance camera that offers a 1000x1000 array of 8 im square pixels, anti-blooming circuitry, and very quick read out. Currently, the system directly converts x-rays to an image with no phosphor. The system is small and light and can be easily adapted to work with other crystallographic equipment. Preliminary images have been acquired of cubic insulin at the NSLS x26c beam line. NSLS x26c was configured for unfocused monochromatic radiation. Six reflections were collected with stills spaced from 0.002 to 0.001 degrees apart across the entire oscillation range that the reflections were in diffracting condition. All of the reflections were rotated to the vertical to reduce Lorentz and beam related effects. This particular CCD is designed for short exposure applications (much less than 1 sec) and so has a relatively high dark current leading to noisy raw images. The images are processed to remove background and other system noise with a multi-step approach including the use of wavelets, histogram, and mean window filtering. After processing, animations were constructed with the corresponding reflection profile to show the diffraction of the crystal volume vs. the oscillation angle as well as composite images showing the parts of the crystal with the strongest diffraction for each reflection. The final goal is to correlate features seen in reflection profiles captured with fine phi slicing to those seen in the topography images. With this development macromolecular topography finally comes into the digital age.
Macromolecular Antioxidants and Dietary Fiber in Edible Seaweeds.
Sanz-Pintos, Nerea; Pérez-Jiménez, Jara; Buschmann, Alejandro H; Vergara-Salinas, José Rodrigo; Pérez-Correa, José Ricardo; Saura-Calixto, Fulgencio
2017-02-01
Seaweeds are rich in different bioactive compounds with potential uses in drugs, cosmetics and the food industry. The objective of this study was to analyze macromolecular antioxidants or nonextractable polyphenols, in several edible seaweed species collected in Chile (Gracilaria chilensis, Callophyllis concepcionensis, Macrocystis pyrifera, Scytosyphon lomentaria, Ulva sp. and Enteromorpha compressa), including their 1st HPLC characterization. Macromolecular antioxidants are commonly ignored in studies of bioactive compounds. They are associated with insoluble dietary fiber and exhibit significant biological activity, with specific features that are different from those of both dietary fiber and extractable polyphenols. We also evaluated extractable polyphenols and dietary fiber, given their relationship with macromolecular antioxidants. Our results show that macromolecular antioxidants are a major polyphenol fraction (averaging 42% to total polyphenol content), with hydroxycinnamic acids, hydroxybenzoic acids and flavonols being the main constituents. This fraction also showed remarkable antioxidant capacity, as determined by 2 complementary assays. The dietary fiber content was over 50% of dry weight, with some samples exhibiting the target proportionality between soluble and insoluble dietary fiber for adequate nutrition. Overall, our data show that seaweed could be an important source of commonly ignored macromolecular antioxidants. © 2017 Institute of Food Technologists®.
Complex Macromolecular Architectures by Living Cationic Polymerization
Alghamdi, Reem D.
2015-05-01
Poly (vinyl ether)-based graft polymers have been synthesized by the combination of living cationic polymerization of vinyl ethers with other living or controlled/ living polymerization techniques (anionic and ATRP). The process involves the synthesis of well-defined homopolymers (PnBVE) and co/terpolymers [PnBVE-b-PCEVE-b-PSiDEGVE (ABC type) and PSiDEGVE-b-PnBVE-b-PSiDEGVE (CAC type)] by sequential living cationic polymerization of n-butyl vinyl ether (nBVE), 2-chloroethyl vinyl ether (CEVE) and tert-butyldimethylsilyl ethylene glycol vinyl ether (SiDEGVE), using mono-functional {[n-butoxyethyl acetate (nBEA)], [1-(2-chloroethoxy) ethyl acetate (CEEA)], [1-(2-(2-(t-butyldimethylsilyloxy)ethoxy) ethoxy) ethyl acetate (SiDEGEA)]} or di-functional [1,4-cyclohexanedimethanol di(1-ethyl acetate) (cHMDEA), (VEMOA)] initiators. The living cationic polymerizations of those monomers were conducted in hexane at -20 0C using Et3Al2Cl3 (catalyst) in the presence of 1 M AcOEt base.[1] The PCEVE segments of the synthesized block terpolymers were then used to react with living macroanions (PS-DPE-Li; poly styrene diphenyl ethylene lithium) to afford graft polymers. The quantitative desilylation of PSiDEGVE segments by n-Bu4N+F- in THF at 0 °C led to graft co- and terpolymers in which the polyalcohol is the outer block. These co-/terpolymers were subsequently subjected to “grafting-from” reactions by atom transfer radical polymerization (ATRP) of styrene to afford more complex macromolecular architectures. The base assisted living cationic polymerization of vinyl ethers were also used to synthesize well-defined α-hydroxyl polyvinylether (PnBVE-OH). The resulting polymers were then modified into an ATRP macro-initiator for the synthesis of well-defined block copolymers (PnBVE-b-PS). Bifunctional PnBVE with terminal malonate groups was also synthesized and used as a precursor for more complex architectures such as H-shaped block copolymer by “grafting-from” or
On a Linear Program for Minimum-Weight Triangulation
Yousefi, Arman
2011-01-01
Minimum-weight triangulation (MWT) is NP-hard. It has a polynomial-time constant-factor approximation algorithm, and a variety of effective polynomial- time heuristics that, for many instances, can find the exact MWT. Linear programs (LPs) for MWT are well-studied, but previously no connection was known between any LP and any approximation algorithm or heuristic for MWT. Here we show the first such connections: for an LP formulation due to Dantzig et al. (1985): (i) the integrality gap is bounded by a constant; (ii) given any instance, if the aforementioned heuristics find the MWT, then so does the LP.
Fast topological construction of delaunay triangulations and voronoi diagrams
Tsai, Victor J. D.
1993-11-01
This paper describes a Convex Hull Insertion algorithm for constructing the Delaunay triangulation and the Voronoi diagram of randomly distributed points in the Euclidean plane. The implemented program on IBM-compatible personal computers takes benefits from the partitioning of data points, topological data structures of spatial primitives, and features in C++ programming language such as dynamic memory allocation and class objects. The program can handle arbitrary collections of points, and delivers several output options to link with GIS and CAD systems. Empirical results of various sets of up to 50,000 points show that the proposed algorithm speeds up the construction of both tessellations of irregular points in expected linear time.
A displacement measurement system based on optical triangulation method
Institute of Scientific and Technical Information of China (English)
FU Xian-bin; LIU Bin; ZHANG Yu-cun
2011-01-01
A new displacement measurement system is described in this paper according to the basic principles of traditional laser triangulation method.The range of the traditional measuring method is enlarged by measuring in sections.Three independent CCDs,which are distributed uniformly along the optical axis,are used to achieve subsection measurement.The plane mirror is regarded as a virtual detector.When imaging beam is reflected by the plane mirror,the beam is imaged on the CCD.The designed system is equivalent to add a CCD.The feasibility of the displacement measurement system is verified by the experiment.
Nested cycles in large triangulations and crossing-critical graphs
Hernandez-Velez, Cesar; Thomas, Robin
2009-01-01
We show that every sufficiently large plane triangulation has a large collection of nested cycles that either are pairwise disjoint, or pairwise intersect in exactly one vertex, or pairwise intersect in exactly two vertices. We apply this result to show that for each fixed positive integer $k$, there are only finitely many $k$-crossing-critical simple graphs of average degree at least six. Combined with the recent constructions of crossing-critical graphs given by Bokal, this settles the question of for which numbers $q>0$ there is an infinite family of $k$-crossing-critical simple graphs of average degree $q$.
Recent development of micro-triangulation for magnet fiducialisation
Vlachakis, Vasileios; Mainaud Durand, Helene; CERN. Geneva. ATS Department
2016-01-01
The micro-triangulation method is proposed as an alternative for magnet fiducialisation. The main objective is to measure horizontal and vertical angles to fiducial points and stretched wires, utilising theodolites equipped with cameras. This study aims to develop various methods, algorithms and software tools to enable the data acquisition and processing. In this paper, we present the first test measurement as an attempt to demonstrate the feasibility of the method and to evaluate the accuracy. The preliminary results are very promising, with accuracy always better than 20 μm for the wire position, and of about40 μm/m for the wire orientation, compared with a coordinate measuring machine.
Triangulation of 3D Surfaces Recovered from STL Grids
Directory of Open Access Journals (Sweden)
D. Rypl
2004-01-01
Full Text Available In the present paper, an algorithm for the discretization of parametric 3D surfaces has been extended to the family of discrete surfaces represented by stereolithography (STL grids. The STL file format, developed for the rapid prototyping industry, is an attractive alternative to surface representation in solid modeling. Initially, a boundary representation is constructed from the STL file using feature recognition. Then a smooth surface is recovered over the original STL grid using an interpolating subdivision procedure. Finally, the reconstructed surface is subjected to the triangulation accomplished using the advancing front technique operating directly on the surface. The capability of the proposed methodology is illustrated on an example.
3D vesicle dynamics simulations with a linearly triangulated surface
Boedec, G.; Leonetti, M.; Jaeger, M.
2011-02-01
Simulations of biomembranes have gained an increasing interest in the past years. Specificities of these membranes propose new challenges for the numerics. In particular, vesicle dynamics are governed by bending forces as well as a surface incompressibility constraint. A method to compute the bending force density resultant onto piecewise linearly triangulated surface meshes is described. This method is coupled with a boundary element method solver for inner and outer fluids, to compute vesicle dynamics under external flows. The surface incompressibility constraint is satisfied by the construction of a projection operator.
Automated Photogrammetric Image Matching with Sift Algorithm and Delaunay Triangulation
DEFF Research Database (Denmark)
Karagiannis, Georgios; Antón Castro, Francesc/François; Mioc, Darka
2016-01-01
An algorithm for image matching of multi-sensor and multi-temporal satellite images is developed. The method is based on the SIFT feature detector proposed by Lowe in (Lowe, 1999). First, SIFT feature points are detected independently in two images (reference and sensed image). The features...... of each feature set for each image are computed. The isomorphism of the Delaunay triangulations is determined to guarantee the quality of the image matching. The algorithm is implemented in Matlab and tested on World-View 2, SPOT6 and TerraSAR-X image patches....
Comparative Study of Triangulation based and Feature based Image Morphing
Directory of Open Access Journals (Sweden)
Ms. Bhumika G. Bhatt
2012-01-01
Full Text Available Image Morphing is one of the most powerful Digital Image processing technique, which is used to enhancemany multimedia projects, presentations, education and computer based training. It is also used inmedical imaging field to recover features not visible in images by establishing correspondence of featuresamong successive pair of scanned images. This paper discuss what morphing is and implementation ofTriangulation based morphing Technique and Feature based Image Morphing. IT analyze both morphingtechniques in terms of different attributes such as computational complexity, Visual quality of morphobtained and complexity involved in selection of features.
A Novel Model of Conforming Delaunay Triangulation for Sensor Network Configuration
Directory of Open Access Journals (Sweden)
Yan Ma
2015-01-01
Full Text Available Delaunay refinement is a technique for generating unstructured meshes of triangles for sensor network configuration engineering practice. A new method for solving Delaunay triangulation problem is proposed in this paper, which is called endpoint triangle’s circumcircle model (ETCM. As compared with the original fractional node refinement algorithms, the proposed algorithm can get well refinement stability with least time cost. Simulations are performed under five aspects including refinement stability, the number of additional nodes, time cost, mesh quality after intruding additional nodes, and the aspect ratio improved by single additional node. All experimental results show the advantages of the proposed algorithm as compared with the existing algorithms and confirm the algorithm analysis sufficiently.
Institute of Scientific and Technical Information of China (English)
无
2005-01-01
Adaptive Delaunay triangulation is combined with the cell-centered upwinding algorithm to analyze inviscid high-speed compressible flow problems. The multidimensional dissipation scheme was developed and included in the upwinding algorithm for unstructured triangular meshes to improve the computed shock wave resolution. The solution accuracy is further improved by coupling an error estimation procedure to a remeshing algorithm that generates small elements in regions with large change of solution gradients, and at the same time, larger elements in other regions. The proposed scheme is further extended to achieve higher-order spatial and temporal solution accuracy. Efficiency of the combined procedure is evaluated by analyzing supersonic shocks and shock propagation behaviors for both the steady and unsteady high-speed compressible flows.
Application of Blue Laser Triangulation Sensors for Displacement Measurement Through Fire.
Hoehler, Matthew S; Smith, Christopher M
2016-11-01
This paper explores the use of blue laser triangulation sensors to measure displacement of a target located behind or in the close proximity of natural gas diffusion flames. This measurement is critical for providing high-quality data in structural fire tests. The position of the laser relative to the flame envelope can significantly affect the measurement scatter, but has little influence on the mean values. We observe that the measurement scatter is normally distributed and increases linearly with the distance of the target from the flame along the beam path. Based on these observations, we demonstrate how time-averaging can be used to achieve a standard uncertainty associated with the displacement error of less than 0.1 mm, which is typically sufficient for structural fire testing applications. Measurements with the investigated blue laser sensors were not impeded by the thermal radiation emitted from the flame or the soot generated from the relatively clean-burning natural gas.
Application of blue laser triangulation sensors for displacement measurement through fire
Hoehler, Matthew S.; Smith, Christopher M.
2016-11-01
This paper explores the use of blue laser triangulation sensors to measure displacement of a target located behind or in the close proximity of natural gas diffusion flames. This measurement is critical for providing high-quality data in structural fire tests. The position of the laser relative to the flame envelope can significantly affect the measurement scatter, but has little influence on the mean values. We observe that the measurement scatter is normally distributed and increases linearly with the distance of the target from the flame along the beam path. Based on these observations, we demonstrate how time-averaging can be used to achieve a standard uncertainty associated with the displacement error of less than 0.1 mm, which is typically sufficient for structural fire testing applications. Measurements with the investigated blue laser sensors were not impeded by the thermal radiation emitted from the flame or the soot generated from the relatively clean-burning natural gas.
Macromolecular crystallography beamline X25 at the NSLS.
Héroux, Annie; Allaire, Marc; Buono, Richard; Cowan, Matthew L; Dvorak, Joseph; Flaks, Leon; Lamarra, Steven; Myers, Stuart F; Orville, Allen M; Robinson, Howard H; Roessler, Christian G; Schneider, Dieter K; Shea-McCarthy, Grace; Skinner, John M; Skinner, Michael; Soares, Alexei S; Sweet, Robert M; Berman, Lonny E
2014-05-01
Beamline X25 at the NSLS is one of the five beamlines dedicated to macromolecular crystallography operated by the Brookhaven National Laboratory Macromolecular Crystallography Research Resource group. This mini-gap insertion-device beamline has seen constant upgrades for the last seven years in order to achieve mini-beam capability down to 20 µm × 20 µm. All major components beginning with the radiation source, and continuing along the beamline and its experimental hutch, have changed to produce a state-of-the-art facility for the scientific community.
Triangulation of the Gigantic Jets in 20 August 2014
Kang-Ming, P.; Hsu, R. R.; Su, H. T.; Chen, A. B. C.; Chou, J. K.; Chang, S. C.; Wu, Y. J.; Chien-Lun, H.; Yang, I. C.; Tsai, S. H.
2015-12-01
Coordinate optical observation campaigns on TLEs near Taiwan are held since 2011 with the aim to triangulate TLEs. Currently, there are four stations with baseline varying from 100 to 400 km between them. Our optical observation systems recorded 48 various types of TLEs on the night of 20 August 2014, with eight of them being gigantic jets that were recorded by at least two stations. Due to the length of baselines and the TLE occurring locations, the earth curvature needed to be taken into account by means of spherical trigonometry method. The preliminary results shows the gigantic jets occurred over the northern Taiwan and the accuracy of geolocation is less than 1 km and the accuracy of the retrieval height on the key structures is less than 0.5 km. The triangulation results of the eight events indicate most of these gigantic jets terminated at 80-90km, but one of the gigantic jets is likely extend to 100 km. Three of the eight gigantic jets occurred consequently after previous one with time interval of 500ms to more than 100s. The previous gigantic jet is likely to influence the consequent gigantic jet for usually the consequent gigantic jet has more beads structures in high altitude and one of the streamer column of a consequent gigantic jets at 55 -60 km is identified to re-bright, which is more than 100s after the previous gigantic jet.
Solving the horizontal conflation problem with a constrained Delaunay triangulation
Ledoux, Hugo; Ohori, Ken Arroyo
2017-01-01
Datasets produced by different countries or organisations are seldom properly aligned and contain several discrepancies (e.g., gaps and overlaps). This problem has been so far almost exclusively tackled by snapping vertices based on a user-defined threshold. However, as we argue in this paper, this leads to invalid geometries, is error-prone, and leaves several discrepancies along the boundaries. We propose a novel algorithm to align the boundaries of adjacent datasets. It is based on a constrained Delaunay triangulation to identify and eliminate the discrepancies, and the alignment is performed without moving vertices with a snapping operator. This allows us to guarantee that the datasets have been properly conflated and that the polygons are geometrically valid. We present our algorithm, our implementation (based on the stable and fast triangulator in CGAL), and we show how it can be used it practice with different experiments with real-world datasets. Our experiments demonstrate that our approach is highly efficient and that it yields better results than snapping-based methods.
Eccentric error and compensation in rotationally symmetric laser triangulation
Institute of Scientific and Technical Information of China (English)
Wang Lei; Gao Jun; Wang Xiaojia; Johannes Eckstein; Peter Ott
2007-01-01
Rotationally symmetric triangulation (RST) sensor has more flexibility and less uncertainty limits becauseof the abaxial rotationally symmetric optical system.But if the incident laser is eccentric,the symmetry of the imagewill descend,and it will result in the eccentric error especially when some part of the imaged ring is blocked.Themodel of rotationally symmetric triangulation that meets the Schimpflug condition is presented in this paper.The errorfrom eccentric incident 1aser is analysed.It iS pointed out that the eccentric error is composed of two parts.one is acosine in circumference and proportional to the eccentric departure factor,and the other is a much smaller quadricfactor of the departure.When the ring is complete,the first error factor is zero because it is integrated in whole ring,but if some part of the ring iS blocked,the first factor will be the main error.Simulation verifies the result of the a-nalysis.At last,a compensation method to the error when some part of the ring is lost is presented based on neuralnetwork.The results of experiment show that the compensation will make the absolute maximum error descend tohalf,and the standard deviation of error descends to 1/3.
Identification of novel autoantigens by a triangulation approach.
Cottrell, Tricia R; Hall, John C; Rosen, Antony; Casciola-Rosen, Livia
2012-11-30
High titer autoantibodies, which are often associated with specific clinical phenotypes, are useful diagnostically and prognostically in systemic autoimmune diseases. In several autoimmune rheumatic diseases (e.g. myositis and Sjogren's syndrome), 20-40% of patients are autoantibody negative as assessed by conventional assays. The recent discovery of new specificities (e.g., anti-MDA5) in a subset of these autoantibody-negative subjects demonstrates that additional specificities await identification. In this manuscript, we describe a rapid multidimensional method to identify new autoantigens. A central foundation of this rapid approach is the use of an antigen source in which a pathogenic pathway active in the disease is recapitulated. Additionally, the method involves a modified serological proteome analysis strategy which allows confirmation that the correct gel plug has been removed prior to sending for sequencing. Lastly, the approach uses multiple sources of information to enable rapid triangulation and identification of protein candidates. Possible permutations and underlying principles of this triangulation strategy are elaborated to demonstrate the broad utility of this approach for antigen discovery.
The finite body triangulation: algorithms, subgraphs, homogeneity estimation and application.
Carson, Cantwell G; Levine, Jonathan S
2016-09-01
The concept of a finite body Dirichlet tessellation has been extended to that of a finite body Delaunay 'triangulation' to provide a more meaningful description of the spatial distribution of nonspherical secondary phase bodies in 2- and 3-dimensional images. A finite body triangulation (FBT) consists of a network of minimum edge-to-edge distances between adjacent objects in a microstructure. From this is also obtained the characteristic object chords formed by the intersection of the object boundary with the finite body tessellation. These two sets of distances form the basis of a parsimonious homogeneity estimation. The characteristics of the spatial distribution are then evaluated with respect to the distances between objects and the distances within them. Quantitative analysis shows that more physically representative distributions can be obtained by selecting subgraphs, such as the relative neighbourhood graph and the minimum spanning tree, from the finite body tessellation. To demonstrate their potential, we apply these methods to 3-dimensional X-ray computed tomographic images of foamed cement and their 2-dimensional cross sections. The Python computer code used to estimate the FBT is made available. Other applications for the algorithm - such as porous media transport and crack-tip propagation - are also discussed.
Automated Photogrammetric Image Matching with Sift Algorithm and Delaunay Triangulation
Karagiannis, Georgios; Antón Castro, Francesc; Mioc, Darka
2016-06-01
An algorithm for image matching of multi-sensor and multi-temporal satellite images is developed. The method is based on the SIFT feature detector proposed by Lowe in (Lowe, 1999). First, SIFT feature points are detected independently in two images (reference and sensed image). The features detected are invariant to image rotations, translations, scaling and also to changes in illumination, brightness and 3-dimensional viewpoint. Afterwards, each feature of the reference image is matched with one in the sensed image if, and only if, the distance between them multiplied by a threshold is shorter than the distances between the point and all the other points in the sensed image. Then, the matched features are used to compute the parameters of the homography that transforms the coordinate system of the sensed image to the coordinate system of the reference image. The Delaunay triangulations of each feature set for each image are computed. The isomorphism of the Delaunay triangulations is determined to guarantee the quality of the image matching. The algorithm is implemented in Matlab and tested on World-View 2, SPOT6 and TerraSAR-X image patches.
A MODIFIED METHOD FOR IMAGE TRIANGULATION USING INCLINED ANGLES
Directory of Open Access Journals (Sweden)
B. Alsadik
2016-06-01
Full Text Available The ongoing technical improvements in photogrammetry, Geomatics, computer vision (CV, and robotics offer new possibilities for many applications requiring efficient acquisition of three-dimensional data. Image orientation is one of these important techniques in many applications like mapping, precise measurements, 3D modeling and navigation. Image orientation comprises three main techniques of resection, intersection (triangulation and relative orientation, which are conventionally solved by collinearity equations or by using projection and fundamental matrices. However, different problems still exist in the state – of –the –art of image orientation because of the nonlinearity and the sensitivity to proper initialization and spatial distribution of the points. In this research, a modified method is presented to solve the triangulation problem using inclined angles derived from the measured image coordinates and based on spherical trigonometry rules and vector geometry. The developed procedure shows promising results compared to collinearity approach and to converge to the global minimum even when starting from far approximations. This is based on the strong geometric constraint offered by the inclined angles that are enclosed between the object points and the camera stations. Numerical evaluations with perspective and panoramic images are presented and compared with the conventional solution of collinearity equations. The results show the efficiency of the developed model and the convergence of the solution to global minimum even with improper starting values.
a Modified Method for Image Triangulation Using Inclined Angles
Alsadik, Bashar
2016-06-01
The ongoing technical improvements in photogrammetry, Geomatics, computer vision (CV), and robotics offer new possibilities for many applications requiring efficient acquisition of three-dimensional data. Image orientation is one of these important techniques in many applications like mapping, precise measurements, 3D modeling and navigation. Image orientation comprises three main techniques of resection, intersection (triangulation) and relative orientation, which are conventionally solved by collinearity equations or by using projection and fundamental matrices. However, different problems still exist in the state - of -the -art of image orientation because of the nonlinearity and the sensitivity to proper initialization and spatial distribution of the points. In this research, a modified method is presented to solve the triangulation problem using inclined angles derived from the measured image coordinates and based on spherical trigonometry rules and vector geometry. The developed procedure shows promising results compared to collinearity approach and to converge to the global minimum even when starting from far approximations. This is based on the strong geometric constraint offered by the inclined angles that are enclosed between the object points and the camera stations. Numerical evaluations with perspective and panoramic images are presented and compared with the conventional solution of collinearity equations. The results show the efficiency of the developed model and the convergence of the solution to global minimum even with improper starting values.
4-D XRD for strain in many grains using triangulation
Energy Technology Data Exchange (ETDEWEB)
Bale, Hrishikesh A.; Hanan, Jay C.; Tamura, Nobumichi
2006-12-31
Determination of the strains in a polycrystalline materialusing 4-D XRD reveals sub-grain and grain-to-grain behavior as a functionof stress. Here 4-D XRD involves an experimental procedure usingpolychromatic micro-beam X-radiation (micro-Laue) to characterizepolycrystalline materials in spatial location as well as with increasingstress. The in-situ tensile loading experiment measured strain in a modelaluminum-sapphire metal matrix composite using the Advanced Light Source,Beam-line 7.3.3. Micro-Laue resolves individual grains in thepolycrystalline matrix. Results obtained from a list of grains sorted bycrystallographic orientation depict the strain states within and amongindividual grains. Locating the grain positions in the planeperpendicular to the incident beam is trivial. However, determining theexact location of grains within a 3-D space is challenging. Determiningthe depth of the grains within the matrix (along the beam direction)involved a triangulation method tracing individual rays that producespots on the CCD back to the point of origin. Triangulation wasexperimentally implemented by simulating a 3-D detector capturingmultiple diffraction images while increasing the camera to sampledistance. Hence by observing the intersection of rays from multiple spotsbelonging to the corresponding grain, depth is calculated. Depthresolution is a function of the number of images collected, grain to beamsize ratio, and the pixel resolution of the CCD. The 4DXRD methodprovides grain morphologies, strain behavior of each grain, andinteractions of the matrix grains with each other and the centrallylocated single crystal fiber.
Two-center-multipole expansion method: application to macromolecular systems
DEFF Research Database (Denmark)
Solov'yov, Ilia; Yakubovich, Alexander V.; Solov'yov, Andrey V.;
2007-01-01
We propose a theoretical method for the calculation of the interaction energy between macromolecular systems at large distances. The method provides a linear scaling of the computing time with the system size and is considered as an alternative to the well-known fast multipole method. Its...
A Detailed Evaluation of a Laser Triangulation Ranging System for Mobile Robots
1983-08-01
A RPI TECHNICAL REPORT MP-82 A DETAILED EVALUATION OF A LASER - TRIANGULATION RANGING SYSTEM FOR MOBILE ROBOTS by Thomas J. Clement Contract MDA-903...Polytechnic Institute Technical Report MP-79, Troy, N.Y., May 1982. 9. McNellis, T., "Evaluation of a Laser Triangulation Ranging System for Mobile Robots ." Rensselaer
DEFF Research Database (Denmark)
an overview of existing triangulation methods with emphasis on performance versus optimality, and will suggest a fast triangulation algorithm based on linear constraints. The structure and camera motion estimation in a SFM system is based on the minimization of some norm of the reprojection error between...
Schwartz, Terry Ann; Kaplan, Michael H.
The benefits accrued through the use of triangulation as both a design strategy and an analytic tool cannot be overstated. Triangulation allows for the clustering and organizing of disparate yet related data. Finding out what the data have in common and how the data are different allow the researcher to eliminate (or reduce) the number of…
A REST Service for Triangulation of Point Sets Using Oriented Matroids
Directory of Open Access Journals (Sweden)
José Antonio Valero Medina
2014-05-01
Full Text Available This paper describes the implementation of a prototype REST service for triangulation of point sets collected by mobile GPS receivers. The first objective of this paper is to test functionalities of an application, which exploits mobile devices’ capabilities to get data associated with their spatial location. A triangulation of a set of points provides a mechanism through which it is possible to produce an accurate representation of spatial data. Such triangulation may be used for representing surfaces by Triangulated Irregular Networks (TINs, and for decomposing complex two-dimensional spatial objects into simpler geometries. The second objective of this paper is to promote the use of oriented matroids for finding alternative solutions to spatial data processing and analysis tasks. This study focused on the particular case of the calculation of triangulations based on oriented matroids. The prototype described in this paper used a wrapper to integrate and expose several tools previously implemented in C++.
Directory of Open Access Journals (Sweden)
Gabriela ȘTEFURA
2014-04-01
Full Text Available The research in tax compliance has approached various methods of data collection, but almost never methodological triangulation has been used. Triangulation helps the researcher in obtaining more reliable results, if they prove to be similar after each method used and also it increases the validity of the entire study. The purpose of the paper is to highlight the importance of triangulation and especially methodological triangulation, by presenting the use of it in researching the compliance behaviour of three categories of individual Romanian taxpayers (doctors, lawyers/notaries and self-employed accountants towards income reporting. Two studies have been conducted: a survey on actual taxpayers and a quasi-experiment on potential taxpayers. The studies had similar results, so the usefulness of triangulation is once again confirmed. The results may be useful to both theorists and practitioners.
Extrinsic curvature in 2-dimensional Causal Dynamical Triangulation
Glaser, Lisa; Weinfurtner, Silke
2016-01-01
Causal Dynamical Triangulations (CDT) is a non-perturbative quantisation of general relativity. Ho\\v{r}ava-Lifshitz gravity on the other hand modifies general relativity to allow for perturbative quan- tisation. Past work has given rise to the speculation that Ho\\v{r}ava-Lifshitz gravity might correspond to the continuum limit of CDT. In this paper we add another piece to this puzzle by applying the CDT quantisation prescription directly to Ho\\v{r}ava-Lifshitz gravity in 2 dimensions. We derive the continuum Hamiltonian and we show that it matches exactly the Hamiltonian one derives from canonically quantising the Ho\\v{r}ava-Lifshitz action. Unlike the standard CDT case, here the intro- duction of a foliated lattice does not impose further restriction on the configuration space and, as a result, lattice quantisation does not leave any imprint on continuum physics as expected.
Quantum Gravity and Matter: Counting Graphs on Causal Dynamical Triangulations
Benedetti, D
2006-01-01
An outstanding challenge for models of non-perturbative quantum gravity is the consistent formulation and quantitative evaluation of physical phenomena in a regime where geometry and matter are strongly coupled. After developing appropriate technical tools, one is interested in measuring and classifying how the quantum fluctuations of geometry alter the behaviour of matter, compared with that on a fixed background geometry. In the simplified context of two dimensions, we show how a method invented to analyze the critical behaviour of spin systems on flat lattices can be adapted to the fluctuating ensemble of curved spacetimes underlying the Causal Dynamical Triangulations (CDT) approach to quantum gravity. We develop a systematic counting of embedded graphs to evaluate the thermodynamic functions of the gravity-matter models in a high- and low-temperature expansion. For the case of the Ising model, we compute the series expansions for the magnetic susceptibility on CDT lattices and their duals up to orders 6 ...
Calibration procedure for a laser triangulation scanner with uncertainty evaluation
Genta, Gianfranco; Minetola, Paolo; Barbato, Giulio
2016-11-01
Most of low cost 3D scanning devices that are nowadays available on the market are sold without a user calibration procedure to correct measurement errors related to changes in environmental conditions. In addition, there is no specific international standard defining a procedure to check the performance of a 3D scanner along time. This paper aims at detailing a thorough methodology to calibrate a 3D scanner and assess its measurement uncertainty. The proposed procedure is based on the use of a reference ball plate and applied to a triangulation laser scanner. Experimental results show that the metrological performance of the instrument can be greatly improved by the application of the calibration procedure that corrects systematic errors and reduces the device's measurement uncertainty.
Spatial analysis of the Chania prefecture: Crete triangulation network quality
Achilleos, Georgios
2016-08-01
The network of trigonometric points of a region is the basis upon which any form of cartographic work is attached to the national geodetic coordinate system (data collection, processing, output presentations) and not only. The products of the cartographic work (cartographic representations), provide the background which is used in cases of spatial planning and development strategy. This trigonometric network, except that, provides to a single cartographic work, the ability to exist within a unified official state geodetic reference system, simultaneously determines the quality of the result, since the trigonometric network data that are used, have their own quality. In this paper, we present the research of spatial quality of the trigonometric network of Chania Prefecture in Crete. This analysis examines the triangulation network points, both with respect to their spatial position (distribution in space), and in their accuracy (horizontally and vertically).
Public Health Triangulation to inform decision-making in Belgium.
Bossuyt, N; Van Casteren, V; Goderis, G; Wens, J; Moreels, S; Vanthomme, K; De Clercq, E
2015-01-01
We assessed the impact of a nation-wide ambulatory care complex intervention (the "care trajectory program") on quality of care in Belgium. We used the three-step public health triangulation method described in this paper and data from four different data sources: a national reimbursement database, an electronic patient record-based general practitioner network, the Belgian general practitioner sentinel network, and a new national registry for care trajectory patients. By applying our method and using the available evidence, we identified key findings that have been accepted by experts and stakeholders. We also produced timely recommendations for the decision-making process, four years after the start of the care trajectory program.
Magnetic Properties and Thermal Entanglement on a Triangulated Kagome Lattice
Ananikian, N S; Chakhmakhchyan, L A; Kocharian, A N
2011-01-01
The magnetic and entanglement thermal (equilibrium) properties in spin-1/2 Ising-Heisenberg model on a triangulated Kagome lattice are analyzed by means of variational mean-field like treatment based on Gibbs-Bogoliubov inequality. Because of the separable character of Ising-type exchange interactions between the Heisenberg trimers the calculation of quantum entanglement in a self-consistent field can be performed for each of the trimers individually. The concurrence in terms of three qubit isotropic Heisenberg model in effective Ising field is non-zero even in the absence of a magnetic field. The magnetic and entanglement properties exhibit common (plateau and peak) features observable via (antferromagnetic) coupling constant and external magnetic field. The critical temperature for the phase transition and threshold temperature for concurrence coincide in the case of antiferromagnetic coupling between qubits. The existence of entangled and disentangled phases in saturated and frustrated phases is establishe...
Feature-preserving surface mesh smoothing via suboptimal Delaunay triangulation.
Gao, Zhanheng; Yu, Zeyun; Holst, Michael
2013-01-01
A method of triangular surface mesh smoothing is presented to improve angle quality by extending the original optimal Delaunay triangulation (ODT) to surface meshes. The mesh quality is improved by solving a quadratic optimization problem that minimizes the approximated interpolation error between a parabolic function and its piecewise linear interpolation defined on the mesh. A suboptimal problem is derived to guarantee a unique, analytic solution that is significantly faster with little loss in accuracy as compared to the optimal one. In addition to the quality-improving capability, the proposed method has been adapted to remove noise while faithfully preserving sharp features such as edges and corners of a mesh. Numerous experiments are included to demonstrate the performance of the method.
Experimental study on subaperture testing with iterative triangulation algorithm.
Yan, Lisong; Wang, Xiaokun; Zheng, Ligong; Zeng, Xuefeng; Hu, Haixiang; Zhang, Xuejun
2013-09-23
Applying the iterative triangulation stitching algorithm, we provide an experimental demonstration by testing a Φ120 mm flat mirror, a Φ1450 mm off-axis parabolic mirror and a convex hyperboloid mirror. By comparing the stitching results with the self-examine subaperture, it shows that the reconstruction results are in consistent with that of the subaperture testing. As all the experiments are conducted with a 5-dof adjustment platform with big adjustment errors, it proves that using the above mentioned algorithm, the subaperture stitching can be easily performed without a precise positioning system. In addition, with the algorithm, we accomplish the coordinate unification between the testing and processing that makes it possible to guide the processing by the stitching result.
Extrinsic curvature in two-dimensional causal dynamical triangulation
Glaser, Lisa; Sotiriou, Thomas P.; Weinfurtner, Silke
2016-09-01
Causal dynamical triangulation (CDT) is a nonperturbative quantization of general relativity. Hořava-Lifshitz gravity, on the other hand, modifies general relativity to allow for perturbative quantization. Past work has given rise to the speculation that Hořava-Lifshitz gravity might correspond to the continuum limit of CDT. In this paper we add another piece to this puzzle by applying the CDT quantization prescription directly to Hořava-Lifshitz gravity in two dimensions. We derive the continuum Hamiltonian, and we show that it matches exactly the Hamiltonian derived from canonically quantizing the Hořava-Lifshitz action. Unlike the standard CDT case, here the introduction of a foliated lattice does not impose further restriction on the configuration space and, as a result, lattice quantization does not leave any imprint on continuum physics as expected.
Causal Dynamical Triangulations in the Spincube Model of Quantum Gravity
Vojinovic, Marko
2015-01-01
We study the implications of the simplicity constraint in the spincube model of quantum gravity. Relating the edge-lengths to integer triangle areas, the simplicity constraint imposes a very strong restrictions between them, ultimately leading to a requirement that all 4-simplices in the triangulation must be almost mutually identical. As a surprising and unexpected consequence of this property, one can obtain the CDT state sum as a special case of the spincube state sum. This relationship brings new insight into the long-standing problem of the relationship between the spinfoam approach and the CDT approach to quantum gravity. In particular, it turns out that the spincube model contains properties of both approaches, providing a single unifying framework for their analysis and comparison. In addition, the spincube state sum also contains some other special cases, very similar but not equivalent to the CDT state sum.
The Subjectivity Problem: Improving Triangulation Approaches in Metaphor Analysis Studies
Directory of Open Access Journals (Sweden)
Sonya L. Armstrong
2011-06-01
Full Text Available Metaphor analysis procedures for uncovering participant conceptualizations have been well-established in qualitative research settings since the early 1980s; however, one common criticism of metaphor analysis is the trustworthiness of the findings. Namely, accurate determination of the conceptual metaphors held by participants based on the investigation of linguistic metaphors has been identified as a methodological issue because of the subjectivity involved in the interpretation; that is, because they are necessarily situated in specific social and cultural milieus, meanings of particular metaphors are not universally constructed nor understood. In light of these critiques, this article provides examples of two different triangulation methods that can be employed to supplement the trustworthiness of the findings when metaphor analysis methodologies are used.
On-Line Metrology with Conoscopic Holography: Beyond Triangulation
Álvarez, Ignacio; Enguita, Jose M.; Frade, María; Marina, Jorge; Ojea, Guillermo
2009-01-01
On-line non-contact surface inspection with high precision is still an open problem. Laser triangulation techniques are the most common solution for this kind of systems, but there exist fundamental limitations to their applicability when high precisions, long standoffs or large apertures are needed, and when there are difficult operating conditions. Other methods are, in general, not applicable in hostile environments or inadequate for on-line measurement. In this paper we review the latest research in Conoscopic Holography, an interferometric technique that has been applied successfully in this kind of applications, ranging from submicrometric roughness measurements, to long standoff sensors for surface defect detection in steel at high temperatures. PMID:22399984
Technique Triangulation for Validation in Directed Content Analysis
Directory of Open Access Journals (Sweden)
Áine M. Humble PhD
2009-09-01
Full Text Available Division of labor in wedding planning varies for first-time marriages, with three types of couples—traditional, transitional, and egalitarian—identified, but nothing is known about wedding planning for remarrying individuals. Using semistructured interviews, the author interviewed 14 couples in which at least one person had remarried and used directed content analysis to investigate the extent to which the aforementioned typology could be transferred to this different context. In this paper she describes how a triangulation of analytic techniques provided validation for couple classifications and also helped with moving beyond “blind spots” in data analysis. Analytic approaches were the constant comparative technique, rank order comparison, and visual representation of coding, using MAXQDA 2007's tool called TextPortraits.
Can causal dynamical triangulations probe factor-ordering issues?
Maitra, R L
2009-01-01
The causal dynamical triangulations (CDT) program has for the first time allowed for path-integral computation of correlation functions in full general relativity without symmetry reductions and taking into account Lorentzian signature. One of the most exciting recent results in CDT is the strong agreement of these computations with (minisuperspace) path integral calculations in quantum cosmology. Herein I will describe my current project to compute minisuperspace (Friedman-Robertson-Walker) path integrals with a range of different measures corresponding to various factor orderings of the Friedman-Robertson-Walker Hamiltonian. The aim is to compare with CDT results and ask whether CDT can shed light on factor-ordering ambiguities in quantum cosmology models.
Causal Dynamical Triangulation of 3D Tensor Model
Kawabe, Hiroshi
2016-01-01
We extend the string field theory of the two dimensional (2D) generalized causal dynamical triangulation (GCDT) with the Ishibashi-Kawai (IK-) type interaction formulated by the matrix model, to the three dimensional (3D) model of the surface field theory. Based on the loop gas model, we construct a tensor model for the discretized surface field and then apply it the stochastic quantization method. In the double scaling limit, the model is characterized by two scaling dimensions $D$ and $D_N$, the power indices of the minimal length as the scaling parameter. The continuum GCDT model with the IK-type interaction is realized with the similar restriction in the $D_N$-$D$ space, to the 2D model. The distinct property in the 3D model is that the quantum effect contains the IK-type interaction only, while the ordinary splitting interaction is excluded.
DEFF Research Database (Denmark)
Bhuiyan, Tanveer Ahmed; Graff, Claus; Kanters, J.K.;
2013-01-01
Drug-induced triangulation of the cardiac action potential is associated with increased risk of arrhythmic events. It has been suggested that triangulation causes a flattening of the electrocardiographic T-wave but the relationship between triangulation, T-wave flattening and onset of arrhythmia...
Jaskolski, Mariusz; Dauter, Zbigniew; Wlodawer, Alexander
2014-09-01
As a contribution to the celebration of the year 2014, declared by the United Nations to be 'The International Year of Crystallography', the FEBS Journal is dedicating this issue to papers showcasing the intimate union between macromolecular crystallography and structural biology, both in historical perspective and in current research. Instead of a formal editorial piece, by way of introduction, this review discusses the most important, often iconic, achievements of crystallographers that led to major advances in our understanding of the structure and function of biological macromolecules. We identified at least 42 scientists who received Nobel Prizes in Physics, Chemistry or Medicine for their contributions that included the use of X-rays or neutrons and crystallography, including 24 who made seminal discoveries in macromolecular sciences. Our spotlight is mostly, but not only, on the recipients of this most prestigious scientific honor, presented in approximately chronological order. As a summary of the review, we attempt to construct a genealogy tree of the principal lineages of protein crystallography, leading from the founding members to the present generation. Published 2014. This article is a U.S. Government work and is in the public domain in the USA.
Force interacts with macromolecular structure in activation of TGF-β.
Dong, Xianchi; Zhao, Bo; Iacob, Roxana E; Zhu, Jianghai; Koksal, Adem C; Lu, Chafen; Engen, John R; Springer, Timothy A
2017-02-02
Integrins are adhesion receptors that transmit force across the plasma membrane between extracellular ligands and the actin cytoskeleton. In activation of the transforming growth factor-β1 precursor (pro-TGF-β1), integrins bind to the prodomain, apply force, and release the TGF-β growth factor. However, we know little about how integrins bind macromolecular ligands in the extracellular matrix or transmit force to them. Here we show how integrin αVβ6 binds pro-TGF-β1 in an orientation biologically relevant for force-dependent release of TGF-β from latency. The conformation of the prodomain integrin-binding motif differs in the presence and absence of integrin binding; differences extend well outside the interface and illustrate how integrins can remodel extracellular matrix. Remodelled residues outside the interface stabilize the integrin-bound conformation, adopt a conformation similar to earlier-evolving family members, and show how macromolecular components outside the binding motif contribute to integrin recognition. Regions in and outside the highly interdigitated interface stabilize a specific integrin/pro-TGF-β orientation that defines the pathway through these macromolecules which actin-cytoskeleton-generated tensile force takes when applied through the integrin β-subunit. Simulations of force-dependent activation of TGF-β demonstrate evolutionary specializations for force application through the TGF-β prodomain and through the β- and not α-subunit of the integrin.
Pool, Robert; Montgomery, Catherine M.; Morar, Neetha S.; Mweemba, Oliver; Ssali, Agnes; Gafos, Mitzy; Lees, Shelley; Stadler, Jonathan; Crook, Angela; Nunn, Andrew; Hayes, Richard; McCormack, Sheena
2010-01-01
Background The collection of accurate data on adherence and sexual behaviour is crucial in microbicide (and other HIV-related) research. In the absence of a “gold standard” the collection of such data relies largely on participant self-reporting. After reviewing available methods, this paper describes a mixed method/triangulation model for generating more accurate data on adherence and sexual behaviour in a multi-centre vaginal microbicide clinical trial. In a companion paper some of the results from this model are presented [1]. Methodology/Principal Findings Data were collected from a random subsample of 725 women (7.7% of the trial population) using structured interviews, coital diaries, in-depth interviews, counting returned gel applicators, focus group discussions, and ethnography. The core of the model was a customised, semi-structured in-depth interview. There were two levels of triangulation: first, discrepancies between data from the questionnaires, diaries, in-depth interviews and applicator returns were identified, discussed with participants and, to a large extent, resolved; second, results from individual participants were related to more general data emerging from the focus group discussions and ethnography. A democratic and equitable collaboration between clinical trialists and qualitative social scientists facilitated the success of the model, as did the preparatory studies preceding the trial. The process revealed some of the underlying assumptions and routinised practices in “clinical trial culture” that are potentially detrimental to the collection of accurate data, as well as some of the shortcomings of large qualitative studies, and pointed to some potential solutions. Conclusions/Significance The integration of qualitative social science and the use of mixed methods and triangulation in clinical trials are feasible, and can reveal (and resolve) inaccuracies in data on adherence and sensitive behaviours, as well as illuminating aspects
Stochastic reaction–diffusion algorithms for macromolecular crowding
Sturrock, Marc
2016-06-01
Compartment-based (lattice-based) reaction–diffusion algorithms are often used for studying complex stochastic spatio-temporal processes inside cells. In this paper the influence of macromolecular crowding on stochastic reaction–diffusion simulations is investigated. Reaction–diffusion processes are considered on two different kinds of compartmental lattice, a cubic lattice and a hexagonal close packed lattice, and solved using two different algorithms, the stochastic simulation algorithm and the spatiocyte algorithm (Arjunan and Tomita 2010 Syst. Synth. Biol. 4, 35–53). Obstacles (modelling macromolecular crowding) are shown to have substantial effects on the mean squared displacement and average number of molecules in the domain but the nature of these effects is dependent on the choice of lattice, with the cubic lattice being more susceptible to the effects of the obstacles. Finally, improvements for both algorithms are presented.
Controlled architecture for improved macromolecular memory within polymer networks.
DiPasquale, Stephen A; Byrne, Mark E
2016-08-01
This brief review analyzes recent developments in the field of living/controlled polymerization and the potential of this technique for creating imprinted polymers with highly structured architecture with macromolecular memory. As a result, it is possible to engineer polymers at the molecular level with increased homogeneity relating to enhanced template binding and transport. Only recently has living/controlled polymerization been exploited to decrease heterogeneity and substantially improve the efficiency of the imprinting process for both highly and weakly crosslinked imprinted polymers. Living polymerization can be utilized to create imprinted networks that are vastly more efficient than similar polymers produced using conventional free radical polymerization, and these improvements increase the role that macromolecular memory can play in the design and engineering of new drug delivery and sensing platforms.
Isotope labeling for NMR studies of macromolecular structure and interactions
Energy Technology Data Exchange (ETDEWEB)
Wright, P.E. [Scripps Research Institute, La Jolla, CA (United States)
1994-12-01
Implementation of biosynthetic methods for uniform or specific isotope labeling of proteins, coupled with the recent development of powerful heteronuclear multidimensional NMR methods, has led to a dramatic increase in the size and complexity of macromolecular systems that are now amenable to NMR structural analysis. In recent years, a new technology has emerged that combines uniform {sup 13}C, {sup 15}N labeling with heteronuclear multidimensional NMR methods to allow NMR structural studies of systems approaching 25 to 30 kDa in molecular weight. In addition, with the introduction of specific {sup 13}C and {sup 15}N labels into ligands, meaningful NMR studies of complexes of even higher molecular weight have become feasible. These advances usher in a new era in which the earlier, rather stringent molecular weight limitations have been greatly surpassed and NMR can begin to address many central biological problems that involve macromolecular structure, dynamics, and interactions.
Refinement of macromolecular structures against neutron data with SHELXL2013.
Gruene, Tim; Hahn, Hinrich W; Luebben, Anna V; Meilleur, Flora; Sheldrick, George M
2014-02-01
Some of the improvements in SHELX2013 make SHELXL convenient to use for refinement of macromolecular structures against neutron data without the support of X-ray data. The new NEUT instruction adjusts the behaviour of the SFAC instruction as well as the default bond lengths of the AFIX instructions. This work presents a protocol on how to use SHELXL for refinement of protein structures against neutron data. It includes restraints extending the Engh & Huber [Acta Cryst. (1991), A47, 392-400] restraints to H atoms and discusses several of the features of SHELXL that make the program particularly useful for the investigation of H atoms with neutron diffraction. SHELXL2013 is already adequate for the refinement of small molecules against neutron data, but there is still room for improvement, like the introduction of chain IDs for the refinement of macromolecular structures.
The vibron dressing in α-helicoidal macromolecular chains
Institute of Scientific and Technical Information of China (English)
D.(C)evizovi(c); S.Galovi(c); A.Reshetnyak; Z.Ivi(c)
2013-01-01
We present a study of the physical properties of the vibrational excitation in α-helicoidal macromolecular chains,caused by the interaction with acoustical and optical phonon modes.The influence of the temperature and the basic system parameters on the vibron dressing have been analyzed by employing the simple mean-field approach based on the variational extension of the Lang-Firsov unitary transformation.The applied approach predicts a region in system parameter space where one has an abrupt transition from a partially dressed (light and mobile) to a fully dressed (immobile) vibron state.We found that the boundary of this region depends on system temperature and the type of bond among structural elements in the macromolecular chain.
A macromolecular model for the endothelial surface layer
Harden, James; Danova-Okpetu, Darina; Grest, Gary
2006-03-01
The endothelial surface layer (ESL) is a micron-scale macromolecular lining of the luminal side of blood vessels composed of proteoglycans, glycoproteins, polysaccharides and associated plasma proteins all in dynamic equilibrium. It has numerous physiological roles including the regulation of blood flow and microvascular permeability, and active participation in mechanotransduction and stress regulation, coagulation, cell adhesion, and inflammatory response. The dynamic structure and the mechanical properties of the ESL are crucial for many of its physiological properties. We present a topological model for the ESL composed of three basic macromolecular elements: branched proteoglycans, linear polysaccharide chains, and small plasma proteins. The model was studied using non-equilibrium molecular dynamics simulations and compared with scaling theories for associating tethered polymers. We discuss the observed dynamical and mechanical properties of the ESL captured by this model, and the possible physical insight it provides into the physiological behavior of the ESL.
A Strategy for the Development of Macromolecular Nonlinear Optical Materials
1990-01-01
obsolete. SECURITY CLASSIFICATION OF THIS PAGE STRATEGY FOR THE DEVELOPMENT OF MACROMOLECULAR NONLINEAR OPTICAL MATERIALS Braja K. Mandala , Jan-Chan...materials is significantly different from the conventional inorganic NLO materials. The extent of second order (quadratic) NLO effect such as second...is a criterion of paramount importance for a large second order electro-optic effect in organic materials 8 ,9 . The most common approach to obtain
Energy Technology Data Exchange (ETDEWEB)
Ralston, Corie; Cork, C.W.; McDermott, G.; Earnest, T.N.
2006-03-28
As part of the annual Advanced Light Source (ALS) andStanford Synchrotron Radiation Laboratory (SSRL) Users' Meeting inOctober of this year, the macromolecular crystallography staff at bothsynchrotrons held a joint hands-on workshop to address automation issuesin crystal mounting and data collection at the beamline. This paperdescribes the ALS portion of the workshop, while the accompanying paperreviews the SSRL workshop.
Single-particle cryo-electron microscopy of macromolecular assemblies
Cheng, Kimberley
2009-01-01
In this thesis, single-particle cryo-electron microscopy (cryo-EM) was used to study the structure of three macromolecular assemblies: the two hemocyanin isoforms from Rapana thomasiana, the Pyrococcus furiosus chaperonin, and the ribosome from Escherichia coli. Hemocyanins are large respiratory proteins in arthropods and molluscs. Most molluscan hemocyanins exist as two distinct isoforms composed of related polypeptides. In most species the two isoforms differ in terms of their oligomeric st...
Energy Technology Data Exchange (ETDEWEB)
Muecke, E.P.; Saias, I.; Zhu, B.
1996-05-01
This paper studies the point location problem in Delaunay triangulations without preprocessing and additional storage. The proposed procedure finds the query point simply by walking through the triangulation, after selecting a good starting point by random sampling. The analysis generalizes and extends a recent result of d = 2 dimensions by proving this procedure to take expected time close to O(n{sup 1/(d+1)}) for point location in Delaunay triangulations of n random points in d = 3 dimensions. Empirical results in both two and three dimensions show that this procedure is efficient in practice.
The Cayley-Bacharach Theorem for Continuous Piecewise Algebraic Curves over Cross-cut Triangulations
Institute of Scientific and Technical Information of China (English)
Renhong WANG; Shaofan WANG
2011-01-01
A piecewise algebraic curve is a curve determined by the zero set of a bivariate spline function.In this paper,we propose the Cayley-Bacharach theorem for continuous piecewise algebraic curves over cross-cut triangulations.We show that,if two continuous piecewise algebraic curves of degrees m and n respectively meet at mnT distinct points over a cross-cut triangulation,where T denotes the number of cells of the triangulation,then any continuous piecewise algebraic curve of degree m + n - 2 containing all but one point of them also contains the last point.
What Macromolecular Crowding Can Do to a Protein
Kuznetsova, Irina M.; Turoverov, Konstantin K.; Uversky, Vladimir N.
2014-01-01
The intracellular environment represents an extremely crowded milieu, with a limited amount of free water and an almost complete lack of unoccupied space. Obviously, slightly salted aqueous solutions containing low concentrations of a biomolecule of interest are too simplistic to mimic the “real life” situation, where the biomolecule of interest scrambles and wades through the tightly packed crowd. In laboratory practice, such macromolecular crowding is typically mimicked by concentrated solutions of various polymers that serve as model “crowding agents”. Studies under these conditions revealed that macromolecular crowding might affect protein structure, folding, shape, conformational stability, binding of small molecules, enzymatic activity, protein-protein interactions, protein-nucleic acid interactions, and pathological aggregation. The goal of this review is to systematically analyze currently available experimental data on the variety of effects of macromolecular crowding on a protein molecule. The review covers more than 320 papers and therefore represents one of the most comprehensive compendia of the current knowledge in this exciting area. PMID:25514413
REFMAC5 for the refinement of macromolecular crystal structures
Energy Technology Data Exchange (ETDEWEB)
Murshudov, Garib N., E-mail: garib@ysbl.york.ac.uk [Structural Biology Laboratory, Department of Chemistry, University of York, Heslington, York YO10 5YW (United Kingdom); Skubák, Pavol [Biophysical Structural Chemistry, Leiden University, PO Box 9502, 2300 RA Leiden (Netherlands); Lebedev, Andrey A. [Structural Biology Laboratory, Department of Chemistry, University of York, Heslington, York YO10 5YW (United Kingdom); Pannu, Navraj S. [Biophysical Structural Chemistry, Leiden University, PO Box 9502, 2300 RA Leiden (Netherlands); Steiner, Roberto A. [Randall Division of Cell and Molecular Biophysics, New Hunt’s House, King’s College London, London (United Kingdom); Nicholls, Robert A. [Structural Biology Laboratory, Department of Chemistry, University of York, Heslington, York YO10 5YW (United Kingdom); Winn, Martyn D. [STFC Daresbury Laboratory, Warrington WA4 4AD (United Kingdom); Long, Fei; Vagin, Alexei A. [Structural Biology Laboratory, Department of Chemistry, University of York, Heslington, York YO10 5YW (United Kingdom)
2011-04-01
The general principles behind the macromolecular crystal structure refinement program REFMAC5 are described. This paper describes various components of the macromolecular crystallographic refinement program REFMAC5, which is distributed as part of the CCP4 suite. REFMAC5 utilizes different likelihood functions depending on the diffraction data employed (amplitudes or intensities), the presence of twinning and the availability of SAD/SIRAS experimental diffraction data. To ensure chemical and structural integrity of the refined model, REFMAC5 offers several classes of restraints and choices of model parameterization. Reliable models at resolutions at least as low as 4 Å can be achieved thanks to low-resolution refinement tools such as secondary-structure restraints, restraints to known homologous structures, automatic global and local NCS restraints, ‘jelly-body’ restraints and the use of novel long-range restraints on atomic displacement parameters (ADPs) based on the Kullback–Leibler divergence. REFMAC5 additionally offers TLS parameterization and, when high-resolution data are available, fast refinement of anisotropic ADPs. Refinement in the presence of twinning is performed in a fully automated fashion. REFMAC5 is a flexible and highly optimized refinement package that is ideally suited for refinement across the entire resolution spectrum encountered in macromolecular crystallography.
Macromolecular amplification of binding response in superaptamer hydrogels.
Bai, Wei; Gariano, Nicholas A; Spivak, David A
2013-05-08
It is becoming more important to detect ultralow concentrations of analytes for biomedical, environmental, and national security applications. Equally important is that new methods should be easy to use, inexpensive, portable, and if possible allow detection by the naked eye. By and large, detection of low concentrations of analytes cannot be achieved directly but requires signal amplification by catalysts, macromolecules, metal surfaces, or supramolecular aggregates. The rapidly progressing field of macromolecular signal amplification has been advanced using conjugated polymers, chirality in polymers, solvating polymers, and polymerization/depolymerization strategies. A new type of aptamer-based hydrogel with specific response to target proteins presented in this report demonstrates an additional category of macromolecular signal amplification. This superaptamer assembly provides the first example of using protein-specific aptamers to create volume-changing hydrogels with amplified response to the target protein. A remarkable aspect of these superaptamer hydrogels is that volume shrinking is visible to the naked eye down to femtomolar concentrations of protein. This extraordinary macromolecular amplification is attributed to a complex interplay between protein-aptamer supramolecular cross-links and the consequential reduction of excluded volume in the hydrogel. Specific recognition is even maintained in biological matrices such as urine and tears. Furthermore, the gels can be dried for long-term storage and regenerated for use without loss of activity. In practice, the ease of this biomarker detection method offers an alternative to traditional analytical techniques that require sophisticated instrumentation and highly trained personnel.
Macromolecular Assemblage in the Design of a Synthetic AIDS Vaccine
Defoort, Jean-Philippe; Nardelli, Bernardetta; Huang, Wolin; Ho, David D.; Tam, James P.
1992-05-01
We describe a peptide vaccine model based on the mimicry of surface coat protein of a pathogen. This model used a macromolecular assemblage approach to amplify peptide antigens in liposomes or micelles. The key components of the model consisted of an oligomeric lysine scaffolding to amplify peptide antigens covalently 4-fold and a lipophilic membrane-anchoring group to further amplify noncovalently the antigens many-fold in liposomal or micellar form. A peptide antigen derived from the third variable domain of glycoprotein gp120 of human immunodeficiency virus type 1 (HIV-1), consisting of neutralizing, T-helper, and T-cytotoxic epitopes, was used in a macromolecular assemblage model (HIV-1 linear peptide amino acid sequence 308-331 in a tetravalent multiple antigen peptide system linked to tripalmitoyl-S-glycerylcysteine). The latter complex, in liposome or micelle, was used to immunize mice and guinea pigs without any adjuvant and found to induce gp120-specific antibodies that neutralize virus infectivity in vitro, elicit cytokine production, and prime CD8^+ cytotoxic T lymphocytes in vivo. Our results show that the macromolecular assemblage approach bears immunological mimicry of the gp120 of HIV virus and may lead to useful vaccines against HIV infection.
3D Laser Triangulation for Plant Phenotyping in Challenging Environments.
Kjaer, Katrine Heinsvig; Ottosen, Carl-Otto
2015-06-09
To increase the understanding of how the plant phenotype is formed by genotype and environmental interactions, simple and robust high-throughput plant phenotyping methods should be developed and considered. This would not only broaden the application range of phenotyping in the plant research community, but also increase the ability for researchers to study plants in their natural environments. By studying plants in their natural environment in high temporal resolution, more knowledge on how multiple stresses interact in defining the plant phenotype could lead to a better understanding of the interaction between plant responses and epigenetic regulation. In the present paper, we evaluate a commercial 3D NIR-laser scanner (PlantEye, Phenospex B.V., Herleen, The Netherlands) to track daily changes in plant growth with high precision in challenging environments. Firstly, we demonstrate that the NIR laser beam of the scanner does not affect plant photosynthetic performance. Secondly, we demonstrate that it is possible to estimate phenotypic variation amongst the growth pattern of ten genotypes of Brassica napus L. (rapeseed), using a simple linear correlation between scanned parameters and destructive growth measurements. Our results demonstrate the high potential of 3D laser triangulation for simple measurements of phenotypic variation in challenging environments and in a high temporal resolution.
Laser triangulation measurement of the level in a coal silo
Institute of Scientific and Technical Information of China (English)
Sun Jiping; Jiang Jing
2011-01-01
Laser triangulation theory was used to develop a novel contact-free method for measuring the coal level in a silo under harsh environmental conditions found in coal mines,such as the presence of dense dust,high humidity,and low illumination.A laser source and a camera were mounted at the top of the silo.The laser spot projected into the silo was imaged by the camera.The pinhole imaging principle allows the level to be found from the lateral shift of the spot image on the sensor.A pre-calibrated look-up table of the coal depth versus spot position was used to obtain the depth.The measurement accuracy depends on the step size used during pre-calibration.The actual application of a device designed according to these principles shows that it is easy to implement.The detection of the coal level in a silo at the low illumination level found in coal mines is demonstrated.
[Illness Concepts of Patients with Schizophrenia: A Triangulation Study].
Wigand, Moritz E; Reichhardt, Lea; Lang, Fabian U; Krumm, Silvia; Jäger, Markus
2017-04-03
Objective Therapists' and patients' concepts of illness often show severe discrepancies. This study explores the illness concepts of patients with schizophrenic disorders (n = 40). Methods Two German scales were used, the "Causal Belief Questionnaire" and the "Illness Concept Scale for Schizophrenic Patients". We compared our data with data published previously. A semi structured interview was performed in a convenience sample (n = 7). Results The domains "trust in medication" and "trust in the treating physician" yielded high scores, yet in comparison with data published 30 years ago, trust in medication is unaltered, while trust in psychiatrists is even slightly lower. Recent psychosocial factors scored high as a possible cause of mental illness. Several patients felt responsible for being mentally ill. No patient in the interview mentioned the neurotransmitter hypothesis of schizophrenia. Conclusion Illness concepts of patients with schizophrenic disorders are a complex phenomenon. Triangulation of quantitative and qualitative methods proves to be a promising approach for future studies. © Georg Thieme Verlag KG Stuttgart · New York.
Triangulating Nucleic Acid Conformations Using Multicolor Surface Energy Transfer.
Riskowski, Ryan A; Armstrong, Rachel E; Greenbaum, Nancy L; Strouse, Geoffrey F
2016-02-23
Optical ruler methods employing multiple fluorescent labels offer great potential for correlating distances among several sites, but are generally limited to interlabel distances under 10 nm and suffer from complications due to spectral overlap. Here we demonstrate a multicolor surface energy transfer (McSET) technique able to triangulate multiple points on a biopolymer, allowing for analysis of global structure in complex biomolecules. McSET couples the competitive energy transfer pathways of Förster Resonance Energy Transfer (FRET) with gold-nanoparticle mediated Surface Energy Transfer (SET) in order to correlate systematically labeled points on the structure at distances greater than 10 nm and with reduced spectral overlap. To demonstrate the McSET method, the structures of a linear B-DNA and a more complex folded RNA ribozyme were analyzed within the McSET mathematical framework. The improved multicolor optical ruler method takes advantage of the broad spectral range and distances achievable when using a gold nanoparticle as the lowest energy acceptor. The ability to report distance information simultaneously across multiple length scales, short-range (10-50 Å), mid-range (50-150 Å), and long-range (150-350 Å), distinguishes this approach from other multicolor energy transfer methods.
A study on the effect of different image centres on stereo triangulation accuracy
CSIR Research Space (South Africa)
De Villiers, J
2015-11-01
Full Text Available This paper evaluates the effect of mixing the distortion centre, principal point and arithmetic image centre on the distortion correction, focal length determination and resulting real-world stereo vision triangulation. A robotic arm is used...
Schaap, Harmen; De Bruijn, Elly; Van der Schaaf, Marieke; Baartman, Liesbeth; Kirschner, Paul A.
2011-01-01
Schaap, H., De Bruijn, E., Van der Schaaf, M. F., Baartman, L. K. J., & Kirschner, P. A. (2011). Explicating students’ personal professional theories in vocational education through multi-method triangulation. Scandinavian Journal of Educational Research, 55, 567-586.
Schaap, Harmen; De Bruijn, Elly; Van der Schaaf, Marieke; Baartman, Liesbeth; Kirschner, Paul A.
2011-01-01
Schaap, H., De Bruijn, E., Van der Schaaf, M. F., Baartman, L. K. J., & Kirschner, P. A. (2011). Explicating students’ personal professional theories in vocational education through multi-method triangulation. Scandinavian Journal of Educational Research, 55, 567-586.
Buehler, Cheryl; Welsh, Deborah P
2009-04-01
This study examined adolescents' emotional reactivity to parents' marital conflict as a mediator of the association between triangulation and adolescents' internalizing problems in a sample of 2-parent families (N = 416)[corrected]. Four waves of annual, multiple-informant data were analyzed (youth ages 11-15 years). The authors used structural equation modeling and found that triangulation was associated with increases in adolescents' internalizing problems, controlling for marital hostility and adolescent externalizing problems. There also was an indirect pathway from triangulation to internalizing problems across time through youths' emotional reactivity. Moderating analyses indicated that the 2nd half of the pathway, the association between emotional reactivity and increased internalizing problems, characterized youth with lower levels of hopefulness and attachment to parents. The findings help detail why triangulation is a risk factor for adolescents' development and which youth will profit most from interventions focused on emotional regulation.
National Research Council Canada - National Science Library
Kim, Katherine K; Browe, Dennis K; Logan, Holly C; Holm, Roberta; Hack, Lori; Ohno-Machado, Lucila
2014-01-01
.... This paper reports on a triangulated approach to developing DRN data governance requirements based on a combination of policy analysis with experts, interviews with institutional leaders, and patient focus groups...
Carrier, Benjamin; MacKinnon, David; Cournoyer, Luc; Beraldin, J.-Angelo
2011-03-01
The National Research Council of Canada (NRC) is currently evaluating and designing artifacts and methods to completely characterize 3-D imaging systems. We have gathered a set of artifacts to form a low-cost portable case and provide a clearly-defined set of procedures for generating characteristic values using these artifacts. In its current version, this case is specifically designed for the characterization of short-range (standoff distance of 1 centimeter to 3 meters) triangulation-based 3-D imaging systems. The case is known as the "NRC Portable Target Case for Short-Range Triangulation-based 3-D Imaging Systems" (NRC-PTC). The artifacts in the case have been carefully chosen for their geometric, thermal, and optical properties. A set of characterization procedures are provided with these artifacts based on procedures either already in use or are based on knowledge acquired from various tests carried out by the NRC. Geometric dimensioning and tolerancing (GD&T), a well-known terminology in the industrial field, was used to define the set of tests. The following parameters of a system are characterized: dimensional properties, form properties, orientation properties, localization properties, profile properties, repeatability, intermediate precision, and reproducibility. A number of tests were performed in a special dimensional metrology laboratory to validate the capability of the NRC-PTC. The NRC-PTC will soon be subjected to reproducibility testing using an intercomparison evaluation to validate its use in different laboratories.
Elbow arthroscopy: a new setup to avoid visual paradox and improve triangulation.
Sinha, Apurv; Pydah, Satya Kanth V; Webb, Mark
2013-05-01
Elbow arthroscopy is a useful diagnostic and therapeutic tool for various conditions. Conventional arthroscopy with the patient in the prone or lateral position where the screen is placed on the opposite side makes it difficult to interpret the image, results in visual paradox, and is associated with difficult triangulation. We present a modified setup for the operating room to help eliminate these problems and improve triangulation.
Thickness and topographic inspection of RPG contact lenses by optical triangulation
Costa, Manuel F. M.
2001-06-01
Optical triangulation as a non-destructive test method extensively proved its usefulness on the dimensional and topographic inspection of a large range of objects and surfaces. In this communication the issue of microtopographic and thickness inspection of hard contact lenses (RPG) is addressed. The use of optical triangulation is discussed based on the results of the application of our MICROTOP.03.MFC microtopographer to this kind of tasks will be presented.
Dynamics simulations for engineering macromolecular interactions
Robinson-Mosher, Avi; Shinar, Tamar; Silver, Pamela A.; Way, Jeffrey
2013-06-01
The predictable engineering of well-behaved transcriptional circuits is a central goal of synthetic biology. The artificial attachment of promoters to transcription factor genes usually results in noisy or chaotic behaviors, and such systems are unlikely to be useful in practical applications. Natural transcriptional regulation relies extensively on protein-protein interactions to insure tightly controlled behavior, but such tight control has been elusive in engineered systems. To help engineer protein-protein interactions, we have developed a molecular dynamics simulation framework that simplifies features of proteins moving by constrained Brownian motion, with the goal of performing long simulations. The behavior of a simulated protein system is determined by summation of forces that include a Brownian force, a drag force, excluded volume constraints, relative position constraints, and binding constraints that relate to experimentally determined on-rates and off-rates for chosen protein elements in a system. Proteins are abstracted as spheres. Binding surfaces are defined radially within a protein. Peptide linkers are abstracted as small protein-like spheres with rigid connections. To address whether our framework could generate useful predictions, we simulated the behavior of an engineered fusion protein consisting of two 20 000 Da proteins attached by flexible glycine/serine-type linkers. The two protein elements remained closely associated, as if constrained by a random walk in three dimensions of the peptide linker, as opposed to showing a distribution of distances expected if movement were dominated by Brownian motion of the protein domains only. We also simulated the behavior of fluorescent proteins tethered by a linker of varying length, compared the predicted Förster resonance energy transfer with previous experimental observations, and obtained a good correspondence. Finally, we simulated the binding behavior of a fusion of two ligands that could
Becoming invisible: The effect of triangulation on children's well-being.
Dallos, Rudi; Lakus, Katarzyna; Cahart, Marie-Stephanie; McKenzie, Rebecca
2016-07-01
The study explored children's experience of triangulation in their families. In all, 15 children aged 11-16 years, who were attending an early intervention family therapy service, participated in the study. The children's understandings and emotional experience of triangulation were explored by comparing their responses to pictures from the Separation Anxiety Test (SAT) and a set of pictures designed for the study depicting a variety of triangulation conflicts in families. An interview regarding the children's personal family experiences of triangulation was also undertaken and clinical information about the children's family contexts was also utilised. Statistical analysis was conducted based on eight of children for whom a full data set was available. This indicated that children showed greater levels of anxiety in response to the triangulation as opposed to the separation scenarios. Qualitative analysis supported this finding and revealed that many of the children felt 'invisible' due to parents' pre-occupation with marital conflict, felt caught in the middle of conflicts and coerced to take sides. Although able to describe their reactions and showing greater negative emotional responses to the triadic pictures, they were not consciously aware of the negative impacts of triangulation on their sense of well-being. Clinical implications are discussed with a focus on encouraging child-centred approaches to family therapy.
Genus dependence of the number of (non-)orientable surface triangulations
Krüger, Benedikt
2016-01-01
Topological triangulations of orientable and non-orientable surfaces with arbitrary genus have important applications in quantum geometry, graph theory and statistical physics. However, until now only the asymptotics for 2-spheres are known analytically, and exact counts of triangulations are only available for both small genus and small triangulations. We apply the Wang-Landau algorithm to calculate the number $N(m,h)$ of triangulations for several order of magnitudes in system size $m$ and genus $h$. We verify that the limit of the entropy density of triangulations is independent of genus and orientability and are able to determine the next-to-leading and the next-to-next-to-leading order terms. We conjecture for the number of surface triangulations the asymptotic behavior \\begin{equation*} N(m,h) \\rightarrow (170.4 \\pm 15.1)^h m^{-2(h - 1)/5} \\left( \\frac{256}{27} \\right)^{m / 2}\\;, \\end{equation*} what might guide a mathematicians proof for the exact asymptotics.
Workshop on algorithms for macromolecular modeling. Final project report, June 1, 1994--May 31, 1995
Energy Technology Data Exchange (ETDEWEB)
Leimkuhler, B.; Hermans, J.; Skeel, R.D.
1995-07-01
A workshop was held on algorithms and parallel implementations for macromolecular dynamics, protein folding, and structural refinement. This document contains abstracts and brief reports from that workshop.
AUTOMATIC MESH GENERATION OF 3-D GEOMETRIC MODELS
Institute of Scientific and Technical Information of China (English)
刘剑飞
2003-01-01
In this paper the presentation of the ball-packing method is reviewed,and a scheme to generate mesh for complex 3-D geometric models is given,which consists of 4 steps:(1)create nodes in 3-D models by ball-packing method,(2)connect nodes to generate mesh by 3-D Delaunay triangulation,(3)retrieve the boundary of the model after Delaunay triangulation,(4)improve the mesh.
A triangulation-invariant method for anisotropic geodesic map computation on surface meshes.
Yoo, Sang Wook; Seong, Joon-Kyung; Sung, Min-Hyuk; Shin, Sung Yo; Cohen, Elaine
2012-10-01
This paper addresses the problem of computing the geodesic distance map from a given set of source vertices to all other vertices on a surface mesh using an anisotropic distance metric. Formulating this problem as an equivalent control theoretic problem with Hamilton-Jacobi-Bellman partial differential equations, we present a framework for computing an anisotropic geodesic map using a curvature-based speed function. An ordered upwind method (OUM)-based solver for these equations is available for unstructured planar meshes. We adopt this OUM-based solver for surface meshes and present a triangulation-invariant method for the solver. Our basic idea is to explore proximity among the vertices on a surface while locally following the characteristic direction at each vertex. We also propose two speed functions based on classical curvature tensors and show that the resulting anisotropic geodesic maps reflect surface geometry well through several experiments, including isocontour generation, offset curve computation, medial axis extraction, and ridge/valley curve extraction. Our approach facilitates surface analysis and processing by defining speed functions in an application-dependent manner.
Manganelli, Joe; Threatt, Anthony; Brooks, Johnell O; Healy, Stan; Merino, Jessica; Yanik, Paul; Walker, Ian; Green, Keith
2014-01-01
This article presents the results of a qualitative study that confirmed, classified, and prioritized user needs for the design of a more useful, usable, and actively assistive over-the-bed table. Manganelli et al. (2014) generated a list of 74 needs for use in developing an actively assistive over-the-bed table. This present study assesses the value and importance of those needs. Fourteen healthcare subject matter experts and eight research and design subject matter experts engaged in a participatory and iterative research and design process. A mixed methods qualitative approach used methodological triangulation to confirm the value of the findings and ratings to establish importance. Open and closed card sorts and a Delphi study were used. Data analysis methods included frequency analysis, content analysis, and a modified Kano analysis. A table demonstrating the needs that are of high importance to both groups of subject matter experts and classification of the design challenges each represents was produced. Through this process, the list of 74 needs was refined to the 37 most important need statements for both groups. Designing a more useful, usable, and actively assistive over-the-bed table is primarily about the ability to position it optimally with respect to the user for any task, as well as improving ease of use and usability. It is also important to make explicit and discuss the differences in priorities and perspectives demonstrated between research and design teams and their clients. © 2014 Vendome Group, LLC.
Recent Major Improvements to the ALS Sector 5 MacromolecularCrystallography Beamlines
Energy Technology Data Exchange (ETDEWEB)
Morton, Simon A.; Glossinger, James; Smith-Baumann, Alexis; McKean, John P.; Trame, Christine; Dickert, Jeff; Rozales, Anthony; Dauz,Azer; Taylor, John; Zwart, Petrus; Duarte, Robert; Padmore, Howard; McDermott, Gerry; Adams, Paul
2007-07-01
Although the Advanced Light Source (ALS) was initially conceived primarily as a low energy (1.9GeV) 3rd generation source of VUV and soft x-ray radiation it was realized very early in the development of the facility that a multipole wiggler source coupled with high quality, (brightness preserving), optics would result in a beamline whose performance across the optimal energy range (5-15keV) for macromolecular crystallography (MX) would be comparable to, or even exceed, that of many existing crystallography beamlines at higher energy facilities. Hence, starting in 1996, a suite of three beamlines, branching off a single wiggler source, was constructed, which together formed the ALS Macromolecular Crystallography Facility. From the outset this facility was designed to cater equally to the needs of both academic and industrial users with a heavy emphasis placed on the development and introduction of high throughput crystallographic tools, techniques, and facilities--such as large area CCD detectors, robotic sample handling and automounting facilities, a service crystallography program, and a tightly integrated, centralized, and highly automated beamline control environment for users. This facility was immediately successful, with the primary Multiwavelength Anomalous Diffraction beamline (5.0.2) in particular rapidly becoming one of the foremost crystallographic facilities in the US--responsible for structures such as the 70S ribosome. This success in-turn triggered enormous growth of the ALS macromolecular crystallography community and spurred the development of five additional ALS MX beamlines all utilizing the newly developed superconducting bending magnets ('superbends') as sources. However in the years since the original Sector 5.0 beamlines were built the performance demands of macromolecular crystallography users have become ever more exacting; with growing emphasis placed on studying larger complexes, more difficult structures, weakly diffracting or
The contrasting effect of macromolecular crowding on amyloid fibril formation.
Directory of Open Access Journals (Sweden)
Qian Ma
Full Text Available BACKGROUND: Amyloid fibrils associated with neurodegenerative diseases can be considered biologically relevant failures of cellular quality control mechanisms. It is known that in vivo human Tau protein, human prion protein, and human copper, zinc superoxide dismutase (SOD1 have the tendency to form fibril deposits in a variety of tissues and they are associated with different neurodegenerative diseases, while rabbit prion protein and hen egg white lysozyme do not readily form fibrils and are unlikely to cause neurodegenerative diseases. In this study, we have investigated the contrasting effect of macromolecular crowding on fibril formation of different proteins. METHODOLOGY/PRINCIPAL FINDINGS: As revealed by assays based on thioflavin T binding and turbidity, human Tau fragments, when phosphorylated by glycogen synthase kinase-3β, do not form filaments in the absence of a crowding agent but do form fibrils in the presence of a crowding agent, and the presence of a strong crowding agent dramatically promotes amyloid fibril formation of human prion protein and its two pathogenic mutants E196K and D178N. Such an enhancing effect of macromolecular crowding on fibril formation is also observed for a pathological human SOD1 mutant A4V. On the other hand, rabbit prion protein and hen lysozyme do not form amyloid fibrils when a crowding agent at 300 g/l is used but do form fibrils in the absence of a crowding agent. Furthermore, aggregation of these two proteins is remarkably inhibited by Ficoll 70 and dextran 70 at 200 g/l. CONCLUSIONS/SIGNIFICANCE: We suggest that proteins associated with neurodegenerative diseases are more likely to form amyloid fibrils under crowded conditions than in dilute solutions. By contrast, some of the proteins that are not neurodegenerative disease-associated are unlikely to misfold in crowded physiological environments. A possible explanation for the contrasting effect of macromolecular crowding on these two sets of
Evolutionary triangulation: informing genetic association studies with evolutionary evidence.
Huang, Minjun; Graham, Britney E; Zhang, Ge; Harder, Reed; Kodaman, Nuri; Moore, Jason H; Muglia, Louis; Williams, Scott M
2016-01-01
Genetic studies of human diseases have identified many variants associated with pathogenesis and severity. However, most studies have used only statistical association to assess putative relationships to disease, and ignored other factors for evaluation. For example, evolution is a factor that has shaped disease risk, changing allele frequencies as human populations migrated into and inhabited new environments. Since many common variants differ among populations in frequency, as does disease prevalence, we hypothesized that patterns of disease and population structure, taken together, will inform association studies. Thus, the population distributions of allelic risk variants should reflect the distributions of their associated diseases. Evolutionary Triangulation (ET) exploits this evolutionary differentiation by comparing population structure among three populations with variable patterns of disease prevalence. By selecting populations based on patterns where two have similar rates of disease that differ substantially from a third, we performed a proof of principle analysis for this method. We examined three disease phenotypes, lactase persistence, melanoma, and Type 2 diabetes mellitus. We show that for lactase persistence, a phenotype with a simple genetic architecture, ET identifies the key gene, lactase. For melanoma, ET identifies several genes associated with this disease and/or phenotypes related to it, such as skin color genes. ET was less obviously successful for Type 2 diabetes mellitus, perhaps because of the small effect sizes in known risk loci and recent environmental changes that have altered disease risk. Alternatively, ET may have revealed new genes involved in conferring disease risk for diabetes that did not meet nominal GWAS significance thresholds. We also compared ET to another method used to filter for phenotype associated genes, population branch statistic (PBS), and show that ET performs better in identifying genes known to associate with
Boat's hull modeling with low-cost triangulation scanners
Guidi, Gabriele; Micoli, Laura L.; Russo, Michele
2005-01-01
In a 3D acquisition project range maps collected around the object to be modeled, need to be integrated. With portable range cameras these range maps are taken from unknown positions and their coordinate systems are local to the sensor. The problem of unifying all the measurements in a single reference system is solved by taking contiguous range maps with a suitable overlap level; taking one map as reference and doing a rototranslation of the adjacent ones by using an "Iterative Closest Point" (ICP) method. Depending on the 3D features over the acquired surface and on the amount of overlapping, the ICP algorithm convergence can be more or less satisfactory. Anyway it always has a random component depending on measurement uncertainty. Therefore, although each individual scan has a very good accuracy, the error's propagation may produce deviations in the aligned set respect to real surface points. In this paper a systematic study of the different alignment modality and the consequent total metric distortions on the final model, is shown. In order to experiment these techniques a case-study of industrial interest was chosen: the 3D modeling of a boat's hull mold. The experiments involved a triangulation based laser scanner integrated with a digital photogrammetry system. In order to check different alignment procedures, a Laser Radar capable to scan all the object surface with a single highly accurate scan, was used to create a "gold-standard" data set. All the experiments were compared with this reference and from the comparison several interesting methodological conclusions have been obtained.
Bringing macromolecular machinery to life using 3D animation.
Iwasa, Janet H
2015-04-01
Over the past decade, there has been a rapid rise in the use of three-dimensional (3D) animation to depict molecular and cellular processes. Much of the growth in molecular animation has been in the educational arena, but increasingly, 3D animation software is finding its way into research laboratories. In this review, I will discuss a number of ways in which 3d animation software can play a valuable role in visualizing and communicating macromolecular structures and dynamics. I will also consider the challenges of using animation tools within the research sphere.
BLOOD FLOW AND MACROMOLECULAR TRANSPORT IN CURVED BLOOD VESSELS
Institute of Scientific and Technical Information of China (English)
WEI Lan; WEN Gong-bi; TAN Wen-chang
2006-01-01
A numerical analysis of the steady/pulsatile flow and macromolecular (such as LDL and Albumin) transport in curved blood vessels was carried out. The computational results predict that the vortex of the secondary flow is time-dependent in the aortic arch.The concentration of macromolecule concentrates at the region of sharp curve, and the wall concentration at the outer part is higher than that at the inner part. Atherosclerosis and thrombosis are prone to develop in such regions with sharp flow.
Chambers, David W
2005-01-01
Groups naturally promote their strengths and prefer values and rules that give them an identity and an advantage. This shows up as generational tensions across cohorts who share common experiences, including common elders. Dramatic cultural events in America since 1925 can help create an understanding of the differing value structures of the Silents, the Boomers, Gen Xers, and the Millennials. Differences in how these generations see motivation and values, fundamental reality, relations with others, and work are presented, as are some applications of these differences to the dental profession.
Bonzom, Valentin
2016-01-01
We review an approach which aims at studying discrete (pseudo--)manifolds in dimension $d\\geq 2$ and called random tensor models. More specifically, we insist on generalizing the two-dimensional notion of $p$-angulations to higher dimensions. To do so, we consider families of triangulations built out of simplices with colored faces. Those simplices can be glued to form new building blocks, called bubbles which are pseudo--manifolds with boundaries. Bubbles can in turn be glued together to form triangulations. The main challenge is to classify the triangulations built from a given set of bubbles with respect to their numbers of bubbles and simplices of codimension two. While the colored triangulations which maximize the number of simplices of codimension two at fixed number of simplices are series-parallel objects called melonic triangulations, this is not always true anymore when restricting attention to colored triangulations built from specific bubbles. This opens up the possibility of new universality clas...
Institute of Scientific and Technical Information of China (English)
熊敏诠
2012-01-01
Delaunay三角剖分方法在空间分析中具有重要地位,文中简要介绍了Delaunay三角网特性和常用的3类算法,并对随机增长法实现过程进行了详细阐述.根据三角分片线性插值原理,求得插值系数,实现对任意点的三角分片线性插值.利用2008年中国2200个观测站的08时24 h降水量资料,对全中国范围及划分的8个区域内相应的0.28125°×0.28125°降水量格点场,使用交叉检验方法,对比分析了三角分片线性插值和反距离权重法的估值准确率.结果表明:在各区域,三角分片线性插值法的均方根误差偏小；在站点较密集的区域,均方根误差、平均绝对误差比较中,三角分片线性插值都有一定的优势；在平均误差对比中,三角分片线性插值优势明显,在全中国范围交叉检验中,三角分片线性插值法对应的年平均误差是0.005 mm,而反距离权重法为-0.107 mm,对其可能的原因进行了分析,证明了Delaunay三角剖分法的合理性.同时,从图形上展示了降水量的Delaunay三角网的三维结构图和三角分片线性插值后的格点场,在直观上,Delaunay三角剖分后得到降水分布和实况保持一致,并有较好的视觉效果；通过三角分片线性插值得到的格点场降水量分布图,克服了反距离权重法的固有缺陷,使获得的降水量格点场趋于合理,提高了插值精度.最后,探讨了Delaunay三角网在气象领域的应用前景.%Delaunay triangulated method plays an important role in the spatial analysis. The characteristic of Delaunay triangu-lation and three kinds of generation algorithm are introduced in this article. The stochastic growth algorithm is also discussed in detail. Based on the principle of the triangulated slice linear interpolation the coefficient is attained and thus the value at an arbitrary point can be calculated through the triangulated slice linear interpolation algorithm. By using the daily precipitation
Enzymes as Green Catalysts for Precision Macromolecular Synthesis.
Shoda, Shin-ichiro; Uyama, Hiroshi; Kadokawa, Jun-ichi; Kimura, Shunsaku; Kobayashi, Shiro
2016-02-24
The present article comprehensively reviews the macromolecular synthesis using enzymes as catalysts. Among the six main classes of enzymes, the three classes, oxidoreductases, transferases, and hydrolases, have been employed as catalysts for the in vitro macromolecular synthesis and modification reactions. Appropriate design of reaction including monomer and enzyme catalyst produces macromolecules with precisely controlled structure, similarly as in vivo enzymatic reactions. The reaction controls the product structure with respect to substrate selectivity, chemo-selectivity, regio-selectivity, stereoselectivity, and choro-selectivity. Oxidoreductases catalyze various oxidation polymerizations of aromatic compounds as well as vinyl polymerizations. Transferases are effective catalysts for producing polysaccharide having a variety of structure and polyesters. Hydrolases catalyzing the bond-cleaving of macromolecules in vivo, catalyze the reverse reaction for bond forming in vitro to give various polysaccharides and functionalized polyesters. The enzymatic polymerizations allowed the first in vitro synthesis of natural polysaccharides having complicated structures like cellulose, amylose, xylan, chitin, hyaluronan, and chondroitin. These polymerizations are "green" with several respects; nontoxicity of enzyme, high catalyst efficiency, selective reactions under mild conditions using green solvents and renewable starting materials, and producing minimal byproducts. Thus, the enzymatic polymerization is desirable for the environment and contributes to "green polymer chemistry" for maintaining sustainable society.
Critical review and perspective of macromolecularly imprinted polymers.
Kryscio, David R; Peppas, Nicholas A
2012-02-01
Molecular recognition is a fundamental and ubiquitous process that is the driving force behind life. Natural recognition elements - including antibodies, enzymes, nucleic acids, and cells - exploit non-covalent interactions to bind to their targets with exceptionally strong affinities. Due to this unparalleled proficiency, scientists have long sought to mimic natural recognition pathways. One promising approach is molecularly imprinted polymers (MIPs), which are fully synthetic systems formed via the crosslinking of organic polymers in the presence of a template molecule, which results in stereo-specific binding sites for this analyte of interest. Macromolecularly imprinted polymers, those synthesized in the presence of macromolecule templates (>1500 Da), are of particular importance because they open up the field for a whole new set of robust diagnostic tools. Although the specific recognition of small-molecular-weight analytes is now considered routine, extension of these efficacious procedures to the protein regime has, thus far, proved challenging. This paper reviews the main approaches employed, highlights studies of interest with an emphasis on recent work, and offers suggestions for future success in the field of macromolecularly imprinted polymers.
MMDB and VAST+: tracking structural similarities between macromolecular complexes.
Madej, Thomas; Lanczycki, Christopher J; Zhang, Dachuan; Thiessen, Paul A; Geer, Renata C; Marchler-Bauer, Aron; Bryant, Stephen H
2014-01-01
The computational detection of similarities between protein 3D structures has become an indispensable tool for the detection of homologous relationships, the classification of protein families and functional inference. Consequently, numerous algorithms have been developed that facilitate structure comparison, including rapid searches against a steadily growing collection of protein structures. To this end, NCBI's Molecular Modeling Database (MMDB), which is based on the Protein Data Bank (PDB), maintains a comprehensive and up-to-date archive of protein structure similarities computed with the Vector Alignment Search Tool (VAST). These similarities have been recorded on the level of single proteins and protein domains, comprising in excess of 1.5 billion pairwise alignments. Here we present VAST+, an extension to the existing VAST service, which summarizes and presents structural similarity on the level of biological assemblies or macromolecular complexes. VAST+ simplifies structure neighboring results and shows, for macromolecular complexes tracked in MMDB, lists of similar complexes ranked by the extent of similarity. VAST+ replaces the previous VAST service as the default presentation of structure neighboring data in NCBI's Entrez query and retrieval system. MMDB and VAST+ can be accessed via http://www.ncbi.nlm.nih.gov/Structure.
Macromolecular Crowding Enhances Thermal Stability of Rabbit Muscle Creatine Kinase
Institute of Scientific and Technical Information of China (English)
ZHU Jiang; HE Huawei; LI Sen
2008-01-01
The effect of dextran on the conformation (or secondary structure) and thermal stability of creatine kinase (CK) was studied using the far-ultraviolet (UV) circular dichroism (CD) spectra.The results showed that lower concentrations of dextran (less than 60 g/L) induced formation of the secondary CK structures.However,the secondary structure content of CK decreased when the dextran concentrations exceeded 60 g/L.Thermally induced transition curves were measured for CK in the presence of different concentrations of dextran by far-UV CD.The thermal transition curves were fitted to a two-state model by a nonlinear,least-squares method to obtain the transition temperature of the unfolding transition.An increase in the tran- sition temperature was observed with the increase of the dextran concentration.These observations qualita-tively accord with predictions of a previously proposed model for the effect of intermolecular excluded volume (macromolecular crowding) on protein stability and conformation.These findings imply that the effects of macromolecular crowding can have an important influence on our understanding of how protein folding oc-curs in vivo.
PRIGo: a new multi-axis goniometer for macromolecular crystallography
Energy Technology Data Exchange (ETDEWEB)
Waltersperger, Sandro; Olieric, Vincent, E-mail: vincent.olieric@psi.ch; Pradervand, Claude [Paul Scherrer Institute, Villigen PSI (Switzerland); Glettig, Wayne [Centre Suisse d’Electronique et Microtechnique SA, Neuchâtel 2002 (Switzerland); Salathe, Marco; Fuchs, Martin R.; Curtin, Adrian; Wang, Xiaoqiang; Ebner, Simon; Panepucci, Ezequiel; Weinert, Tobias [Paul Scherrer Institute, Villigen PSI (Switzerland); Schulze-Briese, Clemens [Dectris Ltd, Baden 5400 (Switzerland); Wang, Meitian, E-mail: vincent.olieric@psi.ch [Paul Scherrer Institute, Villigen PSI (Switzerland)
2015-05-09
The design and performance of the new multi-axis goniometer PRIGo developed at the Swiss Light Source at Paul Scherrer Institute is described. The Parallel Robotics Inspired Goniometer (PRIGo) is a novel compact and high-precision goniometer providing an alternative to (mini-)kappa, traditional three-circle goniometers and Eulerian cradles used for sample reorientation in macromolecular crystallography. Based on a combination of serial and parallel kinematics, PRIGo emulates an arc. It is mounted on an air-bearing stage for rotation around ω and consists of four linear positioners working synchronously to achieve x, y, z translations and χ rotation (0–90°), followed by a ϕ stage (0–360°) for rotation around the sample holder axis. Owing to the use of piezo linear positioners and active correction, PRIGo features spheres of confusion of <1 µm, <7 µm and <10 µm for ω, χ and ϕ, respectively, and is therefore very well suited for micro-crystallography. PRIGo enables optimal strategies for both native and experimental phasing crystallographic data collection. Herein, PRIGo hardware and software, its calibration, as well as applications in macromolecular crystallography are described.
Enhancing Endosomal Escape for Intracellular Delivery of Macromolecular Biologic Therapeutics.
Lönn, Peter; Kacsinta, Apollo D; Cui, Xian-Shu; Hamil, Alexander S; Kaulich, Manuel; Gogoi, Khirud; Dowdy, Steven F
2016-09-08
Bioactive macromolecular peptides and oligonucleotides have significant therapeutic potential. However, due to their size, they have no ability to enter the cytoplasm of cells. Peptide/Protein transduction domains (PTDs), also called cell-penetrating peptides (CPPs), can promote uptake of macromolecules via endocytosis. However, overcoming the rate-limiting step of endosomal escape into the cytoplasm remains a major challenge. Hydrophobic amino acid R groups are known to play a vital role in viral escape from endosomes. Here we utilize a real-time, quantitative live cell split-GFP fluorescence complementation phenotypic assay to systematically analyze and optimize a series of synthetic endosomal escape domains (EEDs). By conjugating EEDs to a TAT-PTD/CPP spilt-GFP peptide complementation assay, we were able to quantitatively measure endosomal escape into the cytoplasm of live cells via restoration of GFP fluorescence by intracellular molecular complementation. We found that EEDs containing two aromatic indole rings or one indole ring and two aromatic phenyl groups at a fixed distance of six polyethylene glycol (PEG) units from the TAT-PTD-cargo significantly enhanced cytoplasmic delivery in the absence of cytotoxicity. EEDs address the critical rate-limiting step of endosomal escape in delivery of macromolecular biologic peptide, protein and siRNA therapeutics into cells.
Transition modes in Ising networks: an approximate theory for macromolecular recognition.
Keating, S; Di Cera, E
1993-07-01
For a statistical lattice, or Ising network, composed of N identical units existing in two possible states, 0 and 1, and interacting according to a given geometry, a set of values can be found for the mean free energy of the 0-->1 transition of a single unit. Each value defines a transition mode in an ensemble of nu N = 3N - 2N possible values and reflects the role played by intermediate states in shaping the energetics of the system as a whole. The distribution of transition modes has a number of intriguing properties. Some of them apply quite generally to any Ising network, regardless of its dimension, while others are specific for each interaction geometry and dimensional embedding and bear on fundamental aspects of analytical number theory. The landscape of transition modes encapsulates all of the important thermodynamic properties of the network. The free energy terms defining the partition function of the system can be derived from the modes by simple transformations. Classical mean-field expressions can be obtained from consideration of the properties of transition modes in a rather straightforward way. The results obtained in the analysis of the transition mode distributions have been used to develop an approximate treatment of the problem of macromolecular recognition. This phenomenon is modeled as a cooperative process that involves a number of recognition subsites across an interface generated by the binding of two macromolecular components. The distribution of allowed binding free energies for the system is shown to be a superposition of Gaussian terms with mean and variance determined a priori by the theory. Application to the analysis of the biologically interaction of thrombin with hirudin has provided some useful information on basic aspects of the interaction, such as the number of recognition subsites involved and the energy balance for binding and cooperative coupling among them. Our results agree quite well with information derived independently
Determination of the human spine curve based on laser triangulation.
Poredoš, Primož; Čelan, Dušan; Možina, Janez; Jezeršek, Matija
2015-02-05
The main objective of the present method was to automatically obtain a spatial curve of the thoracic and lumbar spine based on a 3D shape measurement of a human torso with developed scoliosis. Manual determination of the spine curve, which was based on palpation of the thoracic and lumbar spinous processes, was found to be an appropriate way to validate the method. Therefore a new, noninvasive, optical 3D method for human torso evaluation in medical practice is introduced. Twenty-four patients with confirmed clinical diagnosis of scoliosis were scanned using a specially developed 3D laser profilometer. The measuring principle of the system is based on laser triangulation with one-laser-plane illumination. The measurement took approximately 10 seconds at 700 mm of the longitudinal translation along the back. The single point measurement accuracy was 0.1 mm. Computer analysis of the measured surface returned two 3D curves. The first curve was determined by manual marking (manual curve), and the second was determined by detecting surface curvature extremes (automatic curve). The manual and automatic curve comparison was given as the root mean square deviation (RMSD) for each patient. The intra-operator study involved assessing 20 successive measurements of the same person, and the inter-operator study involved assessing measurements from 8 operators. The results obtained for the 24 patients showed that the typical RMSD between the manual and automatic curve was 5.0 mm in the frontal plane and 1.0 mm in the sagittal plane, which is a good result compared with palpatory accuracy (9.8 mm). The intra-operator repeatability of the presented method in the frontal and sagittal planes was 0.45 mm and 0.06 mm, respectively. The inter-operator repeatability assessment shows that that the presented method is invariant to the operator of the computer program with the presented method. The main novelty of the presented paper is the development of a new, non-contact method
Strongly minimal triangulations of $(S^{3}× S^{1})^{\\# 3}$ and $(S^{3}× S^{1})^{\\# 3}$
Indian Academy of Sciences (India)
Nitin Singh
2015-02-01
A triangulated -manifold , satisfies the inequality $\\binom{f_{0}(K)-d-1}{2}≥ \\binom{d+2}{2}_{1}(K;\\mathbb{Z}_{2})$ for $d≥ 3$. The triangulated -manifolds that meet the bound with equality are called tight neighbourly. In this paper, we present tight neighbourly triangulations of 4-manifolds on 15 vertices with $\\mathbb{Z}_{3}$ as an automorphism group. One such example was constructed by Bagchi and Datta (Discrete Math. 311 (2011) 986-995). We show that there are exactly 12 such triangulations up to isomorphism, 10 of which are orientable.
Fosco, Gregory M; Bray, Bethany C
2016-08-01
Youth appraisals and triangulation into conflicts are key mechanisms by which interparental conflict places youth at risk for psychological maladjustment. Although evidence suggests that there are multiple mechanisms at work (e.g., Fosco & Feinberg, 2015; Grych, Harold, & Miles, 2003), this body of work has relied on variable-centered analyses that are limited to the unique contributions of each process to the variance in outcomes. In reality, it is possible that different combinations of these risk mechanisms may account for multifinality in risk outcomes. Using latent profile analysis (LPA) we examined profiles of threat appraisals, self-blaming attributions, and triangulation in relation to internalizing and externalizing problems in a sample of 285, ethnically diverse high school students. The current analyses revealed 5 distinct profiles of appraisals and triangulation, including an overall low-risk group and a global high-risk group, in which all 3 processes were below average or above average, respectively. Additional profiles included combinations of threat and blame, threat and triangulation, and blame and triangulation. Links between these profiles and emotional distress, problem behavior, and academic outcomes are discussed. (PsycINFO Database Record
Assessment of teaching effectiveness in U.S. Dental schools and the value of triangulation.
Jahangiri, Leila; Mucciolo, Thomas W; Choi, Mijin; Spielman, Andrew I
2008-06-01
The routine evaluation of teaching effectiveness is important in improving faculty, departmental, and institutional efforts. There are three main categories of assessments: those performed by students, peers, and self. Although each category is independently valid, a collection of data from all three categories leads to a more comprehensive outcome and a creation of a triangulation model. The purpose of this study was to identify commonly used methods of assessing teaching effectiveness and to suggest the use of a triangulation model, which has been advocated in the literature on performance assessment as an optimal approach for evaluating teaching effectiveness. A twelve-question survey was sent to all U.S. dental schools to identify evaluation methods as well as to find evidence of triangulation. Thirty-nine out of fifty-seven schools responded. The majority of the schools used student evaluations (81 percent) and peer reviews (78 percent). A minority of schools reported using self-evaluations (31 percent). Less than one in five dental schools reported using all three strategies to achieve triangulation (19 percent). The three most commonly used evaluation methods ("performed routinely") were all in the student evaluation category. Less than half of the schools routinely evaluated clinical teaching effectiveness by any means (42 percent). In conclusion, dental schools should implement a triangulation process, in which evaluation data are obtained from students, peers, and self to provide a comprehensive and composite assessment of teaching effectiveness.
Fotheringham, Diane
2010-03-01
To review the use and usefulness of the methodological strategy of triangulation in the assessment of skill in nursing curricula. Systematic search of the literature relevant to the definition and assessment of skill, reliability and validity of assessment methods and triangulation of assessment strategies. One hundred and twenty papers from nursing, medical, educational and social scientific databases, relevant websites and relevant books were reviewed. Forty papers were included based on their relevance to the theory and methodology of clinical skills assessment of health care professionals, particularly nurses. Papers concerning vocational skills assessment and the assessment of skill in school children were excluded. There is a current imperative within the field of health care professional education to assess clinical skills and to quantify this assessment. However, clinical skill, as it relates to cognition, is poorly defined concept and may be viewed as a quality of the practitioner and, as such, is difficult to quantify. Very many methods of assessing clinical skill have been documented and there are inherent issues in ensuring both reliability and validity of these assessment strategies for clinical skill. This has led commentators to suggest that the process of triangulation should be employed. The paper fundamentally questions whether the concept of triangulation can be applied to skills assessment without dependable measures of reliability and validity of the tools of assessment and concludes that the process of applying multiple modes of assessment should not be confused with the process of triangulation. Copyright 2009 Elsevier Ltd. All rights reserved.
Exploring Euclidean Dynamical Triangulations with a Non-trivial Measure Term
Coumbe, Daniel
2014-01-01
We investigate a nonperturbative formulation of quantum gravity defined via Euclidean dynamical triangulations (EDT) with a non-trivial measure term in the path integral. We are motivated to revisit this older formulation of dynamical triangulations by hints from renormalization group approaches that gravity may be asymptotically safe and by the emergence of a semiclassical phase in causal dynamical triangulations (CDT). We study the phase diagram of this model and identify the two phases that are well known from previous work: the branched polymer phase and the collapsed phase. We verify that the order of the phase transition dividing the branched polymer phase from the collapsed phase is almost certainly first-order. The nontrivial measure term enlarges the phase diagram, allowing us to explore a region of the phase diagram that has been dubbed the crinkled region. Although the collapsed and branched polymer phases have been studied extensively in the literature, the crinkled region has not received the sam...
The role of convexity for solving some shortest path problems in plane without triangulation
An, Phan Thanh; Hai, Nguyen Ngoc; Hoai, Tran Van
2013-09-01
Solving shortest path problems inside simple polygons is a very classical problem in motion planning. To date, it has usually relied on triangulation of the polygons. The question: "Can one devise a simple O(n) time algorithm for computing the shortest path between two points in a simple polygon (with n vertices), without resorting to a (complicated) linear-time triangulation algorithm?" raised by J. S. B. Mitchell in Handbook of Computational Geometry (J. Sack and J. Urrutia, eds., Elsevier Science B.V., 2000), is still open. The aim of this paper is to show that convexity contributes to the design of efficient algorithms for solving some versions of shortest path problems (namely, computing the convex hull of a finite set of points and convex rope on rays in 2D, computing approximate shortest path between two points inside a simple polygon) without triangulation on the entire polygons. New algorithms are implemented in C and numerical examples are presented.
PACMAN study of FSI and micro-triangulation for the pre-alignment of CLIC
Kamugasa, William Solomon
2015-01-01
The alignment precision of linear colliders is extremely demanding owing to the very narrow beam size at the interaction point. Unlike circular colliders, particles in linear colliders have only one chance to collide and are hence tightly focused to maximise the number of interactions per collision. The PACMAN* project is dedicated to study the integration of both fiducialization and alignment of the components on a common support. FSI (Frequency Scanning Interferometry) and Micro-triangulation will contribute to this goal. FSI realized by Etalon AG’s Absolute Multiline system and Micro-triangulation implemented by QDaedalus system developed at ETH Zurich offer precision of 0.5 μm/m and 2.4 μm/m respectively. However, these systems need to be improved in order to provide the necessary geometric information via distance measurements (multilateration) and angle measurements (triangulation), respectively. The paper describes the current status and the future developments of Absolute Multiline and QDaedalus, ...
Fine-grained Delaunay triangulation in a simulation of tumor spheroid growth
Fabbro, A D; Milotti, E; Chignola, Roberto; Fabbro, Alessio Del; Milotti, Edoardo
2006-01-01
The simulation of many-particle systems often requires the detailed knowledge of proximity relations to reduce computational complexity and to provide a basis for specific calculations. Here we describe the basic scheme of a simulator of tumor spheroid growth: the calculation of mechanical interactions between cells and of the concentrations of diffusing chemicals requires a backbone provided by the Delaunay triangulation and the volumes of the associated Voronoi regions. Thus the Delaunay triangulation provides both the proximity relations needed to reduce the computational complexity and the basic structures that are needed to carry out the calculation of the biochemical interactions between cells and with the enviroment. A 3D version of the simulator uses the CGAL library as an essential component for the efficient computation of the Delaunay triangulation and of the Voronoi regions.
Geometric asymptotics for spin foam lattice gauge gravity on arbitrary triangulations
Hellmann, Frank
2012-01-01
We study the behavior of holonomy spin foam partition functions, a form of lattice gauge gravity, on generic 4d-triangulations using micro local analysis. To do so we adapt tools from the renormalization theory of quantum field theory on curved space times. This allows us, for the first time, to study the partition function without taking any limits on the interior of the triangulation. We establish that for many of the most widely used models the geometricity constraints, which reduce the gauge theory to a geometric one, introduce strong accidental curvature constraints. These limit the curvature around each triangle of the triangulation to a finite set of values. We demonstrate how to modify the partition function to avoid this problem. Finally the new methods introduced provide a starting point for studying the regularization ambiguities and renormalization of the partition function.
Triangulation and the importance of establishing valid methods for food safety culture evaluation.
Jespersen, Lone; Wallace, Carol A
2017-10-01
The research evaluates maturity of food safety culture in five multi-national food companies using method triangulation, specifically self-assessment scale, performance documents, and semi-structured interviews. Weaknesses associated with each individual method are known but there are few studies in food safety where a method triangulation approach is used for both data collection and data analysis. Significantly, this research shows that individual results taken in isolation can lead to wrong conclusions, resulting in potentially failing tactics and wasted investments. However, by applying method triangulation and reviewing results from a range of culture measurement tools it is possible to better direct investments and interventions. The findings add to the food safety culture paradigm beyond a single evaluation of food safety culture using generic culture surveys. Copyright © 2017. Published by Elsevier Ltd.
A second look at transition amplitudes in (2+1)-dimensional causal dynamical triangulations
Cooperman, Joshua H; Miller, Jonah M
2016-01-01
Studying transition amplitudes in (2+1)-dimensional causal dynamical triangulations, Cooperman and Miller discovered speculative evidence for Lorentzian quantum geometries emerging from its Euclidean path integral. On the basis of this evidence, Cooperman and Miller conjectured that Lorentzian de Sitter spacetime, not Euclidean de Sitter space, dominates the ground state of the quantum geometry of causal dynamical triangulations on large scales, a scenario akin to that of the Hartle-Hawking no-boundary proposal in which Lorentzian spacetimes dominate a Euclidean path integral. We argue against this conjecture: we propose a more straightforward explanation of their findings, and we proffer evidence for the Euclidean nature of these seemingly Lorentzian quantum geometries. This explanation reveals another manner in which the Euclidean path integral of causal dynamical triangulations behaves correctly in its semiclassical limit--the implementation and interaction of multiple constraints.
Directory of Open Access Journals (Sweden)
Ashatu Hussein
2015-03-01
Full Text Available This article refers to a study in Tanzania on fringe benefits or welfare via the work contract1 where we will work both quantitatively and qualitatively. My focus is on the vital issue of combining methods or methodologies. There has been mixed views on the uses of triangulation in researches. Some authors argue that triangulation is just for increasing the wider and deep understanding of the study phenomenon, while others have argued that triangulation is actually used to increase the study accuracy, in this case triangulation is one of the validity measures. Triangulation is defined as the use of multiple methods mainly qualitative and quantitative methods in studying the same phenomenon for the purpose of increasing study credibility. This implies that triangulation is the combination of two or more methodological approaches, theoretical perspectives, data sources, investigators and analysis methods to study the same phenomenon.However, using both qualitative and quantitative paradigms in the same study has resulted into debate from some researchers arguing that the two paradigms differ epistemologically and ontologically. Nevertheless, both paradigms are designed towards understanding about a particular subject area of interest and both of them have strengths and weaknesses. Thus, when combined there is a great possibility of neutralizing the flaws of one method and strengthening the benefits of the other for the better research results. Thus, to reap the benefits of two paradigms and minimizing the drawbacks of each, the combination of the two approaches have been advocated in this article. The quality of our studies on welfare to combat poverty is crucial, and especially when we want our conclusions to matter in practice.
Manacher, G. K.; Zobrist, A. L.
1979-01-01
The paper addresses the problem of how to find the Greedy Triangulation (GT) efficiently in the average case. It is noted that the problem is open whether there exists an efficient approximation algorithm to the Optimum Triangulation. It is first shown how in the worst case, the GT may be obtained in time O(n to the 3) and space O(n). Attention is then given to how the algorithm may be slightly modified to produce a time O(n to the 2), space O(n) solution in the average case. Finally, it is mentioned that Gilbert has found a worst case solution using totally different techniques that require space O(n to the 2) and time O(n to the 2 log n).
PROFESSOR TEJ PAL SINGH: THE LEGEND OF INDIAN MACROMOLECULAR CRYSTALLOGRAPHY
Directory of Open Access Journals (Sweden)
Md. Imtaiyaz Hassan
2013-12-01
Full Text Available Professor Tej Pal Singh, an internationally recognized Indian scientist par excellence, is one of the pioneers of Indian macromolecular crystallography. He is a person of significant and enduring accomplishments as a teacher, scientist, administrator and family man. He has developed various methods to crystallize wide varieties of proteins. He has successfully determined crystal structures of lactoferrin, phospholipase A2, lactoperoxidase, peptidoglycan recognition proteins, disintegrin, zinc-α2-glycoprotein and several others including various protein-ligand and protein-protein complexes. He has a remarkably high number of structural entries in protein data bank. He received most of the prestigious awards and honors by Indian Government. This article covers most of his research and other achievements which will be a source of inspiration for young scientific community, motivation for peers and joy for his fellow colleagues and friends.
Identification of macromolecular complexes in cryoelectron tomograms of phantom cells
Frangakis, Achilleas S.; Böhm, Jochen; Förster, Friedrich; Nickell, Stephan; Nicastro, Daniela; Typke, Dieter; Hegerl, Reiner; Baumeister, Wolfgang
2002-01-01
Electron tomograms of intact frozen-hydrated cells are essentially three-dimensional images of the entire proteome of the cell, and they depict the whole network of macromolecular interactions. However, this information is not easily accessible because of the poor signal-to-noise ratio of the tomograms and the crowded nature of the cytoplasm. Here, we describe a template matching algorithm that is capable of detecting and identifying macromolecules in tomographic volumes in a fully automated manner. The algorithm is based on nonlinear cross correlation and incorporates elements of multivariate statistical analysis. Phantom cells, i.e., lipid vesicles filled with macromolecules, provide a realistic experimental scenario for an assessment of the fidelity of this approach. At the current resolution of ≈4 nm, macromolecules in the size range of 0.5–1 MDa can be identified with good fidelity. PMID:12391313
Detecting stoichiometry of macromolecular complexes in live cells using FRET
Ben-Johny, Manu; Yue, Daniel N.; Yue, David T.
2016-01-01
The stoichiometry of macromolecular interactions is fundamental to cellular signalling yet challenging to detect from living cells. Fluorescence resonance energy transfer (FRET) is a powerful phenomenon for characterizing close-range interactions whereby a donor fluorophore transfers energy to a closely juxtaposed acceptor. Recognizing that FRET measured from the acceptor's perspective reports a related but distinct quantity versus the donor, we utilize the ratiometric comparison of the two to obtain the stoichiometry of a complex. Applying this principle to the long-standing controversy of calmodulin binding to ion channels, we find a surprising Ca2+-induced switch in calmodulin stoichiometry with Ca2+ channels—one calmodulin binds at basal cytosolic Ca2+ levels while two calmodulins interact following Ca2+ elevation. This feature is curiously absent for the related Na channels, also potently regulated by calmodulin. Overall, our assay adds to a burgeoning toolkit to pursue quantitative biochemistry of dynamic signalling complexes in living cells. PMID:27922011
An analysis of fractal geometry of macromolecular gelation
Institute of Scientific and Technical Information of China (English)
左榘; 陈天红; 冉少峰; 何炳林; 董宝中; 生文君; 杨恒林
1996-01-01
With fractal geometry theory and based on experiments, an analysis of fractal geometry behavior of gelation of macromolecules was carried out. Using the cross-linking copolymerization of styrene-divinylbenzene (DVB) as an example, through the determinations of the evolution of the molecular weight, size and the dependence of scattering intensity on the angle of macromolecules by employing laser and synchrotron small angle X-ray scattering, respectively, this chemical reaction was described quantitatively, its fractal behavior was analyzed and the fractal dimension was also measured. By avoiding the complex theories on gelation, this approach is based on modern physical techniques and theories to perform the analysis of the behavior of fractal geometry of macromolecular gelation and thus is able to reveal the rules of this kind of complicated gelation more essentially and profoundly.
Revealing the macromolecular targets of complex natural products
Reker, Daniel; Perna, Anna M.; Rodrigues, Tiago; Schneider, Petra; Reutlinger, Michael; Mönch, Bettina; Koeberle, Andreas; Lamers, Christina; Gabler, Matthias; Steinmetz, Heinrich; Müller, Rolf; Schubert-Zsilavecz, Manfred; Werz, Oliver; Schneider, Gisbert
2014-12-01
Natural products have long been a source of useful biological activity for the development of new drugs. Their macromolecular targets are, however, largely unknown, which hampers rational drug design and optimization. Here we present the development and experimental validation of a computational method for the discovery of such targets. The technique does not require three-dimensional target models and may be applied to structurally complex natural products. The algorithm dissects the natural products into fragments and infers potential pharmacological targets by comparing the fragments to synthetic reference drugs with known targets. We demonstrate that this approach results in confident predictions. In a prospective validation, we show that fragments of the potent antitumour agent archazolid A, a macrolide from the myxobacterium Archangium gephyra, contain relevant information regarding its polypharmacology. Biochemical and biophysical evaluation confirmed the predictions. The results obtained corroborate the practical applicability of the computational approach to natural product ‘de-orphaning’.
Misra, Santosh K; Srivastava, Indrajit; Tripathi, Indu; Daza, Enrique; Ostadhossein, Fatemeh; Pan, Dipanjan
2017-02-08
Reversible switching of photoluminescence (PL) of carbon nanoparticles (CNP) can be achieved with counterionic macromolecular caging and decaging at the nanoscale. A negatively charged uncoated, "bare" CNP with high luminescence loses its PL when positively charged macromolecules are wrapped around its surface. Prepared caged carbons could regain their emission only through interaction with anionic surfactant molecules, representing anionic amphiphiles of endocytic membranes. This process could be verified by gel electrophoresis, spectroscopically and in vitro confocal imaging studies. Results indicated for the first time that luminescence switchable CNPs can be synthesized for efficient intracellular tracking. This study further supports the origin of photoluminescence in CNP as a surface phenomenon correlated a function of characteristic charged macromolecules.
On macromolecular refinement at subatomic resolution withinteratomic scatterers
Energy Technology Data Exchange (ETDEWEB)
Afonine, Pavel V.; Grosse-Kunstleve, Ralf W.; Adams, Paul D.; Lunin, Vladimir Y.; Urzhumtsev, Alexandre
2007-11-09
A study of the accurate electron density distribution in molecular crystals at subatomic resolution, better than {approx} 1.0 {angstrom}, requires more detailed models than those based on independent spherical atoms. A tool conventionally used in small-molecule crystallography is the multipolar model. Even at upper resolution limits of 0.8-1.0 {angstrom}, the number of experimental data is insufficient for the full multipolar model refinement. As an alternative, a simpler model composed of conventional independent spherical atoms augmented by additional scatterers to model bonding effects has been proposed. Refinement of these mixed models for several benchmark datasets gave results comparable in quality with results of multipolar refinement and superior of those for conventional models. Applications to several datasets of both small- and macro-molecules are shown. These refinements were performed using the general-purpose macromolecular refinement module phenix.refine of the PHENIX package.
Protein Coevolution and Isoexpression in Yeast Macromolecular Complexes
Directory of Open Access Journals (Sweden)
Laurence Ettwiller
2007-01-01
Full Text Available Previous studies in the yeast Saccharomyces cerevisiae have shown that genes encoding subunits of macromolecular complexes have similar evolutionary rates (K and expression levels (E. Besides, it is known that the expression of a gene is a strong predictor of its rate of evolution (i.e., E and K are correlated. Here we show that intracomplex variation of subunit expression correlates with intracomplex variation of their evolutionary rates (using two different measures of dispersion. However, a similar trend was observed for randomized complexes. Therefore, using a mathematical transformation, we created new variables capturing intracomplex variation of both E and K. The values of these new compound variables were smaller for real complexes than for randomized ones. This shows that proteins in complexes tend to have closer expressivities (E and K's simultaneously than in the randomly grouped genes. We speculate about the possible implications of this finding.
[Progress in researches on synthetic antimicrobial macromolecular polymers].
Wei, Gang; Yang, Lihua; Chu, Liangyin
2010-08-01
Broad-spectrum antimicrobial peptides provide a new way to address the urgent growing problem of bacterial resistance. However, the limited natural resources and the high cost of extraction and purification of natural antimicrobial peptides can not meet the requirements of clinical application. In order to solve this problem, researchers have utilized two basic common structural features (amphiphilic and cationic) for designing and preparing synthetic antimicrobial macromolecular polymers. During the last decade, several kinds of amphiphilic polymers, including arylamide oligomers, phenylene ethynylenes, polymethacrylates, polynorbornenes as well as nylon-3 polymers have been synthesized. In this paper, the structures, antibacterial activities and selectivities of these polymers are reviewed, and the effects of molecular size, polarity and ratio of hydrophobic groups, positive charge density on antibacterial activity and selectivity are also summarized.
Macromolecular Crystallization with Microfluidic Free-Interface Diffusion
Energy Technology Data Exchange (ETDEWEB)
Segelke, B
2005-02-24
Fluidigm released the Topaz 1.96 and 4.96 crystallization chips in the fall of 2004. Topaz 1.96 and 4.96 are the latest evolution of Fluidigm's microfluidics crystallization technologies that enable ultra low volume rapid screening for macromolecular crystallization. Topaz 1.96 and 4.96 are similar to each other but represent a major redesign of the Topaz system and have of substantially improved ease of automation and ease of use, improved efficiency and even further reduced amount of material needed. With the release of the new Topaz system, Fluidigm continues to set the standard in low volume crystallization screening which is having an increasing impact in the field of structural genomics, and structural biology more generally. In to the future we are likely to see further optimization and increased utility of the Topaz crystallization system, but we are also likely to see further innovation and the emergence of competing technologies.
In-vacuum long-wavelength macromolecular crystallography.
Wagner, Armin; Duman, Ramona; Henderson, Keith; Mykhaylyk, Vitaliy
2016-03-01
Structure solution based on the weak anomalous signal from native (protein and DNA) crystals is increasingly being attempted as part of synchrotron experiments. Maximizing the measurable anomalous signal by collecting diffraction data at longer wavelengths presents a series of technical challenges caused by the increased absorption of X-rays and larger diffraction angles. A new beamline at Diamond Light Source has been built specifically for collecting data at wavelengths beyond the capability of other synchrotron macromolecular crystallography beamlines. Here, the theoretical considerations in support of the long-wavelength beamline are outlined and the in-vacuum design of the endstation is discussed, as well as other hardware features aimed at enhancing the accuracy of the diffraction data. The first commissioning results, representing the first in-vacuum protein structure solution, demonstrate the promising potential of the beamline.
Extracting trends from two decades of microgravity macromolecular crystallization history
Judge, Russell A.; Snell, Edward H.; van der Woerd, Mark J.
2005-01-01
Since the 1980s hundreds of macromolecular crystal growth experiments have been performed in the reduced acceleration environment of an orbiting spacecraft. Significant enhancements in structural knowledge have resulted from X-ray diffraction of the crystals grown. Similarly, many samples have shown no improvement or degradation in comparison to those grown on the ground. A complex series of interrelated factors affect these experiments and by building a comprehensive archive of the results it was aimed to identify factors that result in success and those that result in failure. Specifically, it was found that dedicated microgravity missions increase the chance of success when compared with those where crystallization took place as a parasitic aspect of the mission. It was also found that the chance of success could not be predicted based on any discernible property of the macromolecule available to us.
NATO Advanced Study Institute on Evolving Methods for Macromolecular Gystallography
Read, Randy J
2007-01-01
X-ray crystallography is the pre-eminent technique for visualizing the structures of macromolecules at atomic resolution. These structures are central to understanding the detailed mechanisms of biological processes, and to discovering novel therapeutics using a structure-based approach. As yet, structures are known for only a small fraction of the proteins encoded by human and pathogenic genomes. To counter the myriad modern threats of disease, there is an urgent need to determine the structures of the thousands of proteins whose structure and function remain unknown. This volume draws on the expertise of leaders in the field of macromolecular crystallography to illuminate the dramatic developments that are accelerating progress in structural biology. Their contributions span the range of techniques from crystallization through data collection, structure solution and analysis, and show how modern high-throughput methods are contributing to a deeper understanding of medical problems.
Macromolecular and dendrimer-based magnetic resonance contrast agents
Energy Technology Data Exchange (ETDEWEB)
Bumb, Ambika; Brechbiel, Martin W. (Radiation Oncology Branch, National Cancer Inst., National Inst. of Health, Bethesda, MD (United States)), e-mail: pchoyke@mail.nih.gov; Choyke, Peter (Molecular Imaging Program, National Cancer Inst., National Inst. of Health, Bethesda, MD (United States))
2010-09-15
Magnetic resonance imaging (MRI) is a powerful imaging modality that can provide an assessment of function or molecular expression in tandem with anatomic detail. Over the last 20-25 years, a number of gadolinium-based MR contrast agents have been developed to enhance signal by altering proton relaxation properties. This review explores a range of these agents from small molecule chelates, such as Gd-DTPA and Gd-DOTA, to macromolecular structures composed of albumin, polylysine, polysaccharides (dextran, inulin, starch), poly(ethylene glycol), copolymers of cystamine and cystine with GD-DTPA, and various dendritic structures based on polyamidoamine and polylysine (Gadomers). The synthesis, structure, biodistribution, and targeting of dendrimer-based MR contrast agents are also discussed
Upper bound theorem for odd-dimensional flag triangulations of manifolds
DEFF Research Database (Denmark)
Adamaszek, Michal Jan; Hladký, Jan
2016-01-01
We prove that among all flag triangulations of manifolds of odd dimension 2r-1, with a sufficient number of vertices, the unique maximizer of the entries of the f-, h-, g- and γ-vector is the balanced join of cycles. Our proof uses methods from extremal graph theory.......We prove that among all flag triangulations of manifolds of odd dimension 2r-1, with a sufficient number of vertices, the unique maximizer of the entries of the f-, h-, g- and γ-vector is the balanced join of cycles. Our proof uses methods from extremal graph theory....
Alpha shape and Delaunay triangulation in studies of protein-related interactions.
Zhou, Weiqiang; Yan, Hong
2014-01-01
In recent years, more 3D protein structures have become available, which has made the analysis of large molecular structures much easier. There is a strong demand for geometric models for the study of protein-related interactions. Alpha shape and Delaunay triangulation are powerful tools to represent protein structures and have advantages in characterizing the surface curvature and atom contacts. This review presents state-of-the-art applications of alpha shape and Delaunay triangulation in the studies on protein-DNA, protein-protein, protein-ligand interactions and protein structure analysis.
A restricted dimer model on a 2-dimensional random causal triangulation
Ambjorn, J; Wheater, J F
2014-01-01
We introduce a restricted hard dimer model on a random causal triangulation that is exactly solvable and generalizes a model recently proposed by Atkin and Zohren. We show that the latter model exhibits unusual behaviour at its multicritical point; in particular, its Hausdorff dimension equals 3 and not 3/2 as would be expected from general scaling arguments. When viewed as a special case of the generalized model introduced here we show that this behaviour is not generic and therefore is not likely to represent the true behaviour of the full dimer model on a random causal triangulation.
Tchebyshev Approximation by S01(Δ)over Some Special Triangulations
Institute of Scientific and Technical Information of China (English)
Ren Hong WANG; Wei DAN
2012-01-01
The critical point set plays a central role in the theory of Tchebyshev approximation.Generally,in multivariate Tchebyshev approximation,it is not a trivial task to determine whether a set is critical or not.In this paper,we study the characterization of the critical point set of S01(△) in geometry,where △ is restricted to some special triangulations (bitriangular,single road and star triangulations). Such geometrical characterization is convenient to use in the determination of a critical point set.
Radiation damage to nucleoprotein complexes in macromolecular crystallography
Energy Technology Data Exchange (ETDEWEB)
Bury, Charles; Garman, Elspeth F.; Ginn, Helen Mary [University of Oxford, South Parks Road, Oxford OX1 3QU (United Kingdom); Ravelli, Raimond B. G. [Maastricht University, PO Box 616, Maastricht 6200 MD (Netherlands); Carmichael, Ian [University of Notre Dame, Notre Dame, IN 46556 (United States); Kneale, Geoff; McGeehan, John E., E-mail: john.mcgeehan@port.ac.uk [University of Portsmouth, King Henry 1st Street, Portsmouth PO1 2DY (United Kingdom)
2015-01-30
Quantitative X-ray induced radiation damage studies employing a model protein–DNA complex revealed a striking partition of damage sites. The DNA component was observed to be far more resistant to specific damage compared with the protein. Significant progress has been made in macromolecular crystallography over recent years in both the understanding and mitigation of X-ray induced radiation damage when collecting diffraction data from crystalline proteins. In contrast, despite the large field that is productively engaged in the study of radiation chemistry of nucleic acids, particularly of DNA, there are currently very few X-ray crystallographic studies on radiation damage mechanisms in nucleic acids. Quantitative comparison of damage to protein and DNA crystals separately is challenging, but many of the issues are circumvented by studying pre-formed biological nucleoprotein complexes where direct comparison of each component can be made under the same controlled conditions. Here a model protein–DNA complex C.Esp1396I is employed to investigate specific damage mechanisms for protein and DNA in a biologically relevant complex over a large dose range (2.07–44.63 MGy). In order to allow a quantitative analysis of radiation damage sites from a complex series of macromolecular diffraction data, a computational method has been developed that is generally applicable to the field. Typical specific damage was observed for both the protein on particular amino acids and for the DNA on, for example, the cleavage of base-sugar N{sub 1}—C and sugar-phosphate C—O bonds. Strikingly the DNA component was determined to be far more resistant to specific damage than the protein for the investigated dose range. At low doses the protein was observed to be susceptible to radiation damage while the DNA was far more resistant, damage only being observed at significantly higher doses.
Youngs, Howard; Piggot-Irvine, Eileen
2012-01-01
Mixed methods research has emerged as a credible alternative to unitary research approaches. The authors show how a combination of a triangulation convergence model with a triangulation multilevel model was used to research an aspiring school principal development pilot program. The multilevel model is used to show the national and regional levels…
Tonkin-Crine, Sarah; Anthierens, Sibyl; Hood, Kerenza; Yardley, Lucy; Cals, Jochen W L; Francis, Nick A; Coenen, Samuel; van der Velden, Alike W; Godycki-Cwirko, Maciek; Llor, Carl; Butler, Chris C; Verheij, Theo J M; Goossens, Herman; Little, Paul
2016-01-01
BACKGROUND: Mixed methods are commonly used in health services research; however, data are not often integrated to explore complementarity of findings. A triangulation protocol is one approach to integrating such data. A retrospective triangulation protocol was carried out on mixed methods data coll
Youngs, Howard; Piggot-Irvine, Eileen
2012-01-01
Mixed methods research has emerged as a credible alternative to unitary research approaches. The authors show how a combination of a triangulation convergence model with a triangulation multilevel model was used to research an aspiring school principal development pilot program. The multilevel model is used to show the national and regional levels…
Tonkin-Crine, Sarah; Anthierens, Sibyl; Hood, Kerenza; Yardley, Lucy; Cals, Jochen W L; Francis, Nick A; Coenen, Samuel; van der Velden, Alike W; Godycki-Cwirko, Maciek; Llor, Carl; Butler, Chris C; Verheij, Theo J M; Goossens, Herman; Little, Paul
2016-01-01
BACKGROUND: Mixed methods are commonly used in health services research; however, data are not often integrated to explore complementarity of findings. A triangulation protocol is one approach to integrating such data. A retrospective triangulation protocol was carried out on mixed methods data
A graph theoretical approach for assessing bio-macromolecular complex structural stability.
Del Carpio, Carlos Adriel; Iulian Florea, Mihai; Suzuki, Ai; Tsuboi, Hideyuki; Hatakeyama, Nozomu; Endou, Akira; Takaba, Hiromitsu; Ichiishi, Eiichiro; Miyamoto, Akira
2009-11-01
Fast and proper assessment of bio macro-molecular complex structural rigidity as a measure of structural stability can be useful in systematic studies to predict molecular function, and can also enable the design of rapid scoring functions to rank automatically generated bio-molecular complexes. Based on the graph theoretical approach of Jacobs et al. [Jacobs DJ, Rader AJ, Kuhn LA, Thorpe MF (2001) Protein flexibility predictions using graph theory. Proteins: Struct Funct Genet 44:150-165] for expressing molecular flexibility, we propose a new scheme to analyze the structural stability of bio-molecular complexes. This analysis is performed in terms of the identification in interacting subunits of clusters of flappy amino acids (those constituting regions of potential internal motion) that undergo an increase in rigidity at complex formation. Gains in structural rigidity of the interacting subunits upon bio-molecular complex formation can be evaluated by expansion of the network of intra-molecular inter-atomic interactions to include inter-molecular inter-atomic interaction terms. We propose two indices for quantifying this change: one local, which can express localized (at the amino acid level) structural rigidity, the other global to express overall structural stability for the complex. The new system is validated with a series of protein complex structures reported in the protein data bank. Finally, the indices are used as scoring coefficients to rank automatically generated protein complex decoys.
Majasalmi, Titta; Korhonen, Lauri; Korpela, Ilkka; Vauhkonen, Jari
2017-07-01
We propose 3D triangulations of airborne Laser Scanning (ALS) point clouds as a new approach to derive 3D canopy structures and to estimate forest canopy effective LAI (LAIe). Computational geometry and topological connectivity were employed to filter the triangulations to yield a quasi-optimal relationship with the field measured LAIe. The optimal filtering parameters were predicted based on ALS height metrics, emulating the production of maps of LAIe and canopy volume for large areas. The LAIe from triangulations was validated with field measured LAIe and compared with a reference LAIe calculated from ALS data using logarithmic model based on Beer's law. Canopy transmittance was estimated using All Echo Cover Index (ACI), and the mean projection of unit foliage area (β) was obtained using no-intercept regression with field measured LAIe. We investigated the influence species and season on the triangulated LAIe and demonstrated the relationship between triangulated LAIe and canopy volume. Our data is from 115 forest plots located at the southern boreal forest area in Finland and for each plot three different ALS datasets were available to apply the triangulations. The triangulation approach was found applicable for both leaf-on and leaf-off datasets after initial calibration. Results showed the Root Mean Square Errors (RMSEs) between LAIe from triangulations and field measured values agreed the most using the highest pulse density data (RMSE = 0.63, the coefficient of determination (R2) = 0.53). Yet, the LAIe calculated using ACI-index agreed better with the field measured LAIe (RMSE = 0.53 and R2 = 0.70). The best models to predict the optimal alpha value contained the ACI-index, which indicates that within-crown transmittance is accounted by the triangulation approach. The cover indices may be recommended for retrieving LAIe only, but for applications which require more sophisticated information on canopy shape and volume, such as radiative transfer models, the
Triangulation and Mixed Methods Designs: Data Integration with New Research Technologies
Fielding, Nigel G.
2012-01-01
Data integration is a crucial element in mixed methods analysis and conceptualization. It has three principal purposes: illustration, convergent validation (triangulation), and the development of analytic density or "richness." This article discusses such applications in relation to new technologies for social research, looking at three…
Evaluating Team Project-Work Using Triangulation: Lessons from Communities in Northern Ghana
Clark, Gordon; Jasaw, Godfred Seidu
2014-01-01
This paper uses triangulation to assess key aspects of a team-based, participatory action research programme for undergraduates in rural communities across northern Ghana. The perceptions of the programme and its effects on the students, staff and host communities are compared, showing areas of agreement and disagreement. The successes of the…
Triangulation and Mixed Methods Designs: Data Integration with New Research Technologies
Fielding, Nigel G.
2012-01-01
Data integration is a crucial element in mixed methods analysis and conceptualization. It has three principal purposes: illustration, convergent validation (triangulation), and the development of analytic density or "richness." This article discusses such applications in relation to new technologies for social research, looking at three…
Hesse-Biber, Sharlene
2012-01-01
This article explores the deployment of triangulation in the service of uncovering subjugated knowledge and promoting social change for women and other oppressed groups. Feminist approaches to mixed methods praxis create a tight link between the research problem and the research design. An analysis of selected case studies of feminist praxis…
Modelling and calibration of the laser beam-scanning triangulation measurement system
Wang, Guoyu; Zheng, Bing; Li, Xin; Houkes, Z.; Regtien, P.P.L.
2002-01-01
We present an approach of modelling and calibration of an active laser beam-scanning triangulation measurement system. The system works with the pattern of two-dimensional beam-scanning illumination and one-dimensional slit-scanning detection with a photo-multiplier tube instead of a CCD camera. By
Xu, Jun; Lee, Jennifer C.
2013-01-01
In this article, we propose a shift in race research from a one-dimensional hierarchical approach to a multidimensional system of racial stratification. Building upon Claire Kim's (1999) racial triangulation theory, we examine how the American public rates Asians relative to blacks and whites along two dimensions of racial stratification: racial…
Zhang, Hanlin; Ren, Yongjie; Liu, Changjie; Zhu, Jigui
2014-07-10
High-speed surface profile measurement with high precision is crucial for target inspection and quality control. In this study, a laser scanner based on a single point laser triangulation displacement sensor and a high-speed rotating polygon mirror is proposed. The autosynchronized scanning scheme is introduced to alleviate the trade-off between the field of view and the range precision, which is the inherent deficiency of the conventional triangulation. The lateral synchronized flying spot technology has excellent characteristics, such as programmable and larger field of view, high immunity to ambient light or secondary reflections, high optical signal-to-noise ratio, and minimum shadow effect. Owing to automatic point-to-point laser power control, high accuracy and superior data quality are possible when measuring objects featuring varying surface characteristics even in demanding applications. The proposed laser triangulation scanner is validated using a laboratory-built prototype and practical considerations for design and implementation of the system are described, including speckle noise reduction method and real-time signal processing. A method for rapid and accurate calibration of the laser triangulation scanner using lookup tables is also devised, and the system calibration accuracy is generally smaller than ±0.025 mm. Experimental results are presented and show a broad application prospect for fast surface profile precision measurement.
Triangulation and Mixed Methods Designs: Data Integration with New Research Technologies
Fielding, Nigel G.
2012-01-01
Data integration is a crucial element in mixed methods analysis and conceptualization. It has three principal purposes: illustration, convergent validation (triangulation), and the development of analytic density or "richness." This article discusses such applications in relation to new technologies for social research, looking at three innovative…
Theoretical Triangulation as an Approach for Revealing the Complexity of a Classroom Discussion
van Drie, Jannet; Dekker, Rijkje
2013-01-01
In this paper we explore the value of theoretical triangulation as a methodological approach for the analysis of classroom interaction. We analyze an excerpt of a whole-class discussion in history from three theoretical perspectives: interactivity of the discourse, conceptual level raising and historical reasoning. We conclude that using…
DEFF Research Database (Denmark)
Zhang, Guojie; Pei, Zhang; Krawczak, Michael;
2010-01-01
Triangulation of the human, chimpanzee, and Neanderthal genome sequences with respect to 44,348 disease-causing or disease-associated missense mutations and 1,712 putative regulatory mutations listed in the Human Gene Mutation Database was employed to identify genetic variants that are apparently...
Some specific triangulated categories%几个具体的三角范畴
Institute of Scientific and Technical Information of China (English)
赵小娟
2012-01-01
Peng proposed two methods to construct triangulated categories from generalized chain complex categories and functors between them. In this paper, the author uses these methods to consider some specific triangulated categories, determines all the indecomposable objects of the triangulated categories and their concrete forms. Then, the author draws their Auslander-Reiten quivers. From these Auslander-Reiten quivers one can see that they also provide a new kind of realization for the orbit categories of some triangulated categories.%本文利用彭提出的用广义复形范畴以及广义复形范畴之间的锥扩张来构造三角范畴的方法,考虑了几类特殊的三角范畴,确定了这几类三角范畴的所有不可分解对象和它们的具体形式,并给出了它们的Auslander-Reiten箭图的结构.这些三角范畴提供了一些轨道范畴的一种新的实现.
A restricted dimer model on a two-dimensional random causal triangulation
DEFF Research Database (Denmark)
Ambjørn, Jan; Durhuus, Bergfinnur; Wheater, J. F.
2014-01-01
We introduce a restricted hard dimer model on a random causal triangulation that is exactly solvable and generalizes a model recently proposed by Atkin and Zohren (2012 Phys. Lett. B 712 445–50). We show that the latter model exhibits unusual behaviour at its multicritical point; in particular, its...
Modelling and calibration of the laser beam-scanning triangulation measurement system
Wang, G.Y.; Zheng, Bing; Li, Xin; Houkes, Z.; Regtien, Paulus P.L.
2002-01-01
We present an approach of modelling and calibration of an active laser beam-scanning triangulation measurement system. The system works with the pattern of two-dimensional beam-scanning illumination and one-dimensional slit-scanning detection with a photo-multiplier tube instead of a CCD camera. By
Xu, Jun; Lee, Jennifer C.
2013-01-01
In this article, we propose a shift in race research from a one-dimensional hierarchical approach to a multidimensional system of racial stratification. Building upon Claire Kim's (1999) racial triangulation theory, we examine how the American public rates Asians relative to blacks and whites along two dimensions of racial stratification: racial…
Evaluating Team Project-Work Using Triangulation: Lessons from Communities in Northern Ghana
Clark, Gordon; Jasaw, Godfred Seidu
2014-01-01
This paper uses triangulation to assess key aspects of a team-based, participatory action research programme for undergraduates in rural communities across northern Ghana. The perceptions of the programme and its effects on the students, staff and host communities are compared, showing areas of agreement and disagreement. The successes of the…
Theoretical Triangulation as an Approach for Revealing the Complexity of a Classroom Discussion
van Drie, Jannet; Dekker, Rijkje
2013-01-01
In this paper we explore the value of theoretical triangulation as a methodological approach for the analysis of classroom interaction. We analyze an excerpt of a whole-class discussion in history from three theoretical perspectives: interactivity of the discourse, conceptual level raising and historical reasoning. We conclude that using…
Oliver, Kathryn; Aicken, Catherine; Arai, Lisa
2013-01-01
Drawing lessons from research can help policy makers make better decisions. If a large and methodologically varied body of research exists, as with childhood obesity, this is challenging. We present new research and policy objectives for child obesity developed by triangulating user involvement data with a mapping study of interventions aimed at…
Symmetry and Transitive Properties of Monohedral f-triangulations of the Riemannian Sphere
Institute of Scientific and Technical Information of China (English)
Ana M. BREDA; J. M. SIGARRETA
2009-01-01
Here we give the complete description of the symmetry group and transitive properties of the set of all of monohedral triangulations of the Riemannian sphere by f-tilings. We shall also show that each monohedral f-tiling of the Riemannian sphere can be seen, up to a spherical isometry, as the singular set of a spherical isometric folding.
Hesse-Biber, Sharlene
2012-01-01
This article explores the deployment of triangulation in the service of uncovering subjugated knowledge and promoting social change for women and other oppressed groups. Feminist approaches to mixed methods praxis create a tight link between the research problem and the research design. An analysis of selected case studies of feminist praxis…
Four-dimensional Causal Dynamical Triangulations and an effective transfer matrix
Görlich, Andrzej
2013-01-01
Causal Dynamical Triangulations is a background independent approach to quantum gravity. We show that there exists an effective transfer matrix labeled by the scale factor which properly describes the evolution of the quantum universe. In this framework no degrees of freedom are frozen, but, the obtained effective action agrees with the minisuperspace model.
Core requirements for successful data linkage: an example of a triangulation method.
Hopf, Y M; Francis, J; Helms, P J; Haughney, J; Bond, C
2016-10-21
The aim was to explore the views of professional stakeholders and healthcare professionals (HCPs) on the linkage of UK National Health Service (NHS) data for paediatric pharmacovigilance purposes and to make recommendations for such a system. A mixed methods approach including a literature review, interviews, focus groups and a three-round Delphi survey with HCPs in Scotland was followed by a triangulation process using a systematic protocol. The survey was structured using the Theoretical Domains Framework of behaviour change. Items retained after applying the matrix-based triangulation process were thematically coded. Ethical approval was granted by the North of Scotland Research Ethics Service. Results from 18 papers, 23 interviewees, 23 participants of focus groups and 61 completed questionnaires in the Delphi survey contributed to the triangulation process. A total of 25 key findings from all four studies were identified during triangulation. There was good convergence; 21 key findings were agreed and remained to inform recommendations. The items were coded as practical/technical (eg, decision about the unique patient identifier to use), mandatory (eg, governed by statute), essential (consistently mentioned in all studies and therefore needed to ensure professional support) or preferable. The development of a paediatric linked database has support from professional stakeholders and HCPs in Scotland. The triangulation identified three sets of core requirements for a new system of data linkage. An additional fourth set of 'preferable' requirements might increase engagement of HCPs and their support for the new system. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://www.bmj.com/company/products-services/rights-and-licensing/.
Macromolecular crowding for tailoring tissue-derived fibrillated matrices.
Magno, Valentina; Friedrichs, Jens; Weber, Heather M; Prewitz, Marina C; Tsurkan, Mikhail V; Werner, Carsten
2017-06-01
Tissue-derived fibrillated matrices can be instrumental for the in vitro reconstitution of multiphasic extracellular microenvironments. However, despite of several advantages, the obtained scaffolds so far offer a rather narrow range of materials characteristics only. In this work, we demonstrate how macromolecular crowding (MMC) - the supplementation of matrix reconstitution media with synthetic or natural macromolecules in ways to create excluded volume effects (EVE) - can be employed for tailoring important structural and biophysical characteristics of kidney-derived fibrillated matrices. Porcine kidneys were decellularized, ground and the obtained extracellular matrix (ECM) preparations were reconstituted under varied MMC conditions. We show that MMC strongly influences the fibrillogenesis kinetics and impacts the architecture and the elastic modulus of the reconstituted matrices, with diameters and relative alignment of fibrils increasing at elevated concentrations of the crowding agent Ficoll400, a nonionic synthetic polymer of sucrose. Furthermore, we demonstrate how MMC modulates the distribution of key ECM molecules within the reconstituted matrix scaffolds. As a proof of concept, we compared different variants of kidney-derived fibrillated matrices in cell culture experiments referring to specific requirements of kidney tissue engineering approaches. The results revealed that MMC-tailored matrices support the morphogenesis of human umbilical vein endothelial cells (HUVECs) into capillary networks and of murine kidney stem cells (KSCs) into highly branched aggregates. The established methodology is concluded to provide generally applicable new options for tailoring tissue-specific multiphasic matrices in vitro. Tissue-derived fibrillated matrices can be instrumental for the in vitro reconstitution of multiphasic extracellular microenvironments. However, despite of several advantages, the obtained scaffolds so far offer a rather narrow range of materials
NMR RELAXIVITY AND IMAGING OF NEUTRAL MACROMOLECULAR POLYESTER GADOLINIUM (Ⅲ) COMPLEXES
Institute of Scientific and Technical Information of China (English)
Kai-chao Yu; Hong-bing Hu; Mai-li Liu; Han-zhen Yuan; Chao-hui Ye; Ren-xi Zhuo
1999-01-01
Five neutral macromolecular polyester gadolinium (Ⅲ) complexes with pendant hydrophobic alkyl and aromatic functional groups were prepared. The longitudinal relaxation rates of these complexes were measured. One of these Gd (Ⅲ) complexes was chosen for the acute toxicity test and T1-weighted imaging measurement. Preliminary results showed that. compared with Gd-DTPA, the neutral macromolecular gadolinium (Ⅲ) complexes provide higher T1 relaxivity enhancement and longer function duration.
Stereo matching and view interpolation based on image domain triangulation.
Fickel, Guilherme Pinto; Jung, Claudio R; Malzbender, Tom; Samadani, Ramin; Culbertson, Bruce
2013-09-01
This paper presents a new approach for stereo matching and view interpolation problems based on triangular tessellations suitable for a linear array of rectified cameras. The domain of the reference image is initially partitioned into triangular regions using edge and scale information, aiming to place vertices along image edges and increase the number of triangles in textured regions. A region-based matching algorithm is then used to find an initial disparity for each triangle, and a refinement stage is applied to change the disparity at the vertices of the triangles, generating a piecewise linear disparity map. A simple post-processing procedure is applied to connect triangles with similar disparities generating a full 3D mesh related to each camera (view), which are used to generate new synthesized views along the linear camera array. With the proposed framework, view interpolation reduces to the trivial task of rendering polygonal meshes, which can be done very fast, particularly when GPUs are employed. Furthermore, the generated views are hole-free, unlike most point-based view interpolation schemes that require some kind of post-processing procedures to fill holes.
[The triangulation of help relationships, decryption and challenges].
Jung, Élodie; Lozac'h, Charlotte
2014-01-01
Situations involving people struggling with their day-to-day living activities, family carers, professionals and many other players are complex. Each is singular, evolves, and is sometimes difficult to decipher. While supporting a family member can be a wonderful human adventure, some situations generate extreme suffering.
Computing a Canonical Polygonal Schema of an Orientable Triangulated Surface
Lazarus, Francis; Pocchiola, Michel; Vegter, Gert; Verroust, Anne
2001-01-01
A closed orientable surface of genus g can be obtained by appropriate identification of pairs of edges of a 4g-gon (the polygonal schema). The identified edges form 2g loops on the surface, that are disjoint except for their common end-point. These loops are generators of both the fundamental group
Directory of Open Access Journals (Sweden)
Haiyan Wu
Full Text Available The rapid, sensitive and low-cost detection of macromolecular biomarkers is critical in clinical diagnostics, environmental monitoring, research, etc. Conventional assay methods usually require bulky, expensive and designated instruments and relative long assay time. For hospitals and laboratories that lack immediate access to analytical instruments, fast and low-cost assay methods for the detection of macromolecular biomarkers are urgently needed. In this work, we developed a versatile microparticle (MP-based immunoaggregation method for the detection and quantification of macromolecular biomarkers. Antibodies (Abs were firstly conjugated to MP through streptavidin-biotin interaction; the addition of macromolecular biomarkers caused the aggregation of Ab-MPs, which were subsequently detected by an optical microscope or optical particle sizer. The invisible nanometer-scale macromolecular biomarkers caused detectable change of micrometer-scale particle size distributions. Goat anti-rabbit immunoglobulin and human ferritin were used as model biomarkers to demonstrate MP-based immunoaggregation assay in PBS and 10% FBS to mimic real biomarker assay in the complex medium. It was found that both the number ratio and the volume ratio of Ab-MP aggregates caused by biomarker to all particles were directly correlated to the biomarker concentration. In addition, we found that the detection range could be tuned by adjusting the Ab-MP concentration. We envision that this novel MP-based immunoaggregation assay can be combined with multiple detection methods to detect and quantify macromolecular biomarkers at the nanogram per milliliter level.
JBluIce-EPICS control system for macromolecular crystallography.
Energy Technology Data Exchange (ETDEWEB)
Stepanov, S.; Makarov, O.; Hilgart, M.; Pothineni, S.; Urakhchin, A.; Devarapalli, S.; Yoder, D.; Becker, M.; Ogata, C.; Sanishvili, R.; Nagarajan, V.; Smith, J. L.; Fischetti, R. F. (Biosciences Division); (Univ. of Michigan)
2011-01-01
The trio of macromolecular crystallography beamlines constructed by the General Medicine and Cancer Institutes Collaborative Access Team (GM/CA-CAT) in Sector 23 of the Advanced Photon Source (APS) have been in growing demand owing to their outstanding beam quality and capacity to measure data from crystals of only a few micrometres in size. To take full advantage of the state-of-the-art mechanical and optical design of these beamlines, a significant effort has been devoted to designing fast, convenient, intuitive and robust beamline controls that could easily accommodate new beamline developments. The GM/CA-CAT beamline controls are based on the power of EPICS for distributed hardware control, the rich Java graphical user interface of Eclipse RCP and the task-oriented philosophy as well as the look and feel of the successful SSRL BluIce graphical user interface for crystallography. These beamline controls feature a minimum number of software layers, the wide use of plug-ins that can be written in any language and unified motion controls that allow on-the-fly scanning and optimization of any beamline component. This paper describes the ways in which BluIce was combined with EPICS and converted into the Java-based JBluIce, discusses the solutions aimed at streamlining and speeding up operations and gives an overview of the tools that are provided by this new open-source control system for facilitating crystallographic experiments, especially in the field of microcrystallography.
Patch-clamp detection of macromolecular translocation along nuclear pores
Directory of Open Access Journals (Sweden)
Bustamante J.O.
1998-01-01
Full Text Available The present paper reviews the application of patch-clamp principles to the detection and measurement of macromolecular translocation along the nuclear pores. We demonstrate that the tight-seal 'gigaseal' between the pipette tip and the nuclear membrane is possible in the presence of fully operational nuclear pores. We show that the ability to form a gigaseal in nucleus-attached configurations does not mean that only the activity of channels from the outer membrane of the nuclear envelope can be detected. Instead, we show that, in the presence of fully operational nuclear pores, it is likely that the large-conductance ion channel activity recorded derives from the nuclear pores. We conclude the technical section with the suggestion that the best way to demonstrate that the nuclear pores are responsible for ion channel activity is by showing with fluorescence microscopy the nuclear translocation of ions and small molecules and the exclusion of the same from the cisterna enclosed by the two membranes of the envelope. Since transcription factors and mRNAs, two major groups of nuclear macromolecules, use nuclear pores to enter and exit the nucleus and play essential roles in the control of gene activity and expression, this review should be useful to cell and molecular biologists interested in understanding how patch-clamp can be used to quantitate the translocation of such macromolecules into and out of the nucleus
Timely deposition of macromolecular structures is necessary for peer review
Energy Technology Data Exchange (ETDEWEB)
Joosten, Robbie P. [Netherlands Cancer Institute, Plesmanlaan 121, 1066 CX Amsterdam (Netherlands); Soueidan, Hayssam; Wessels, Lodewyk F. A. [Netherlands Cancer Institute, Plesmanlaan 121, 1066 CX, Amsterdam (Netherlands); Perrakis, Anastassis, E-mail: a.perrakis@nki.nl [Netherlands Cancer Institute, Plesmanlaan 121, 1066 CX Amsterdam (Netherlands)
2013-12-01
Deposition of crystallographic structures should be concurrent with or prior to manuscript submission for peer review, enabling validation and increasing reliability of the PDB. Most of the macromolecular structures in the Protein Data Bank (PDB), which are used daily by thousands of educators and scientists alike, are determined by X-ray crystallography. It was examined whether the crystallographic models and data were deposited to the PDB at the same time as the publications that describe them were submitted for peer review. This condition is necessary to ensure pre-publication validation and the quality of the PDB public archive. It was found that a significant proportion of PDB entries were submitted to the PDB after peer review of the corresponding publication started, and many were only submitted after peer review had ended. It is argued that clear description of journal policies and effective policing is important for pre-publication validation, which is key in ensuring the quality of the PDB and of peer-reviewed literature.
Synchrotron radiation macromolecular crystallography: science and spin-offs
Directory of Open Access Journals (Sweden)
John R. Helliwell
2015-03-01
Full Text Available A current overview of synchrotron radiation (SR in macromolecular crystallography (MX instrumentation, methods and applications is presented. Automation has been and remains a central development in the last decade, as have the rise of remote access and of industrial service provision. Results include a high number of Protein Data Bank depositions, with an increasing emphasis on the successful use of microcrystals. One future emphasis involves pushing the frontiers of using higher and lower photon energies. With the advent of X-ray free-electron lasers, closely linked to SR developments, the use of ever smaller samples such as nanocrystals, nanoclusters and single molecules is anticipated, as well as the opening up of femtosecond time-resolved diffraction structural studies. At SR sources, a very high-throughput assessment for the best crystal samples and the ability to tackle just a few micron and sub-micron crystals will become widespread. With higher speeds and larger detectors, diffraction data volumes are becoming long-term storage and archiving issues; the implications for today and the future are discussed. Together with the rise of the storage ring to its current pre-eminence in MX data provision, the growing tendency of central facility sites to offer other centralized facilities complementary to crystallography, such as cryo-electron microscopy and NMR, is a welcome development.
New concepts and applications in the macromolecular chemistry of fullerenes.
Giacalone, Francesco; Martín, Nazario
2010-10-08
A new classification on the different types of fullerene-containing polymers is presented according to their different properties and applications they exhibit in a variety of fields. Because of their interest and novelty, water-soluble and biodegradable C(60)-polymers are discussed first, followed by polyfullerene-based membranes where unprecedented supramolecular structures are presented. Next are compounds that involve hybrid materials formed from fullerenes and other components such as silica, DNA, and carbon nanotubes (CNTs) where the most recent advances have been achieved. A most relevant topic is still that of C(60)-based donor-acceptor (D-A) polymers. Since their application in photovoltaics D-A polymers are among the most realistic applications of fullerenes in the so-called molecular electronics. The most relevant aspects in these covalently connected fullerene/polymer hybrids as well as new concepts to improve energy conversion efficiencies are presented.The last topics disccused relate to supramolecular aspects that are in involved in C(60)-polymer systems and in the self-assembly of C(60)-macromolecular structures, which open a new scenario for organizing, by means of non-covalent interactions, new supramolecular structures at the nano- and micrometric scale, in which the combination of the hydrofobicity of fullerenes with the versatility of the noncovalent chemistry afford new and spectacular superstructures.
Macromolecular metallurgy of binary mesocrystals via designed multiblock terpolymers.
Xie, Nan; Liu, Meijiao; Deng, Hanlin; Li, Weihua; Qiu, Feng; Shi, An-Chang
2014-02-26
Self-assembling block copolymers provide access to the fabrication of various ordered phases. In particular, the ordered spherical phases can be used to engineer soft mesocrystals with domain size at the 5-100 nm scales. Simple block copolymers, such as diblock copolymers, form a limited number of mesocrystals. However multiblock copolymers are capable to form more complex mesocrystals. We demonstrate that designed B1AB2CB3 multiblock terpolymers, in which the A- and C-blocks form spherical domains and the packing of these spheres can be controlled by changing the lengths of the middle and terminal B-blocks, self-assemble into various binary mesocrystals with space group symmetries of a large number of binary ionic crystals, including NaCl, CsCl, ZnS, α-BN, AlB2, CaF2, TiO2, ReO3, Li3Bi, Nb3Sn(A15), and α-Al2O3. This approach can be generalized to other terpolymers as well as to tetrapolymers to obtain ternary mesocrystals. Our study provides a new concept of macromolecular metallurgy for producing crystal phases in a mesoscale and thus makes multiblock copolymers a robust platform for the engineering of functional materials.
Macromolecular Powder Diffraction: Ready for genuine biological problems.
Karavassili, Fotini; Margiolaki, Irene
2016-01-01
Knowledge of 3D structures of biological molecules plays a major role in both understanding important processes of life and developing pharmaceuticals. Among several methods available for structure determination, macromolecular X-ray powder diffraction (XRPD) has transformed over the past decade from an impossible dream to a respectable method. XRPD can be employed in biosciences for various purposes such as observing phase transitions, characterizing bulk pharmaceuticals, determining structures via the molecular replacement method, detecting ligands in protein-ligand complexes, as well as combining micro-sized single crystal crystallographic data and powder diffraction data. Studies using synchrotron and laboratory sources in some standard configuration setups are reported in this review, including their respective advantages and disadvantages. Methods presented here provide an alternative, complementary set of tools to resolve structural problems. A variety of already existing software packages for powder diffraction data processing and analysis, some of which have been adapted to large unit cell studies, are briefly described. This review aims to provide necessary elements of theory and current methods, along with practical explanations, available software packages and highlighted case studies.
Canadian macromolecular crystallography facility: a suite of fully automated beamlines.
Grochulski, Pawel; Fodje, Michel; Labiuk, Shaunivan; Gorin, James; Janzen, Kathryn; Berg, Russ
2012-06-01
The Canadian light source is a 2.9 GeV national synchrotron radiation facility located on the University of Saskatchewan campus in Saskatoon. The small-gap in-vacuum undulator illuminated beamline, 08ID-1, together with the bending magnet beamline, 08B1-1, constitute the Canadian Macromolecular Crystallography Facility (CMCF). The CMCF provides service to more than 50 Principal Investigators in Canada and the United States. Up to 25% of the beam time is devoted to commercial users and the general user program is guaranteed up to 55% of the useful beam time through a peer-review process. CMCF staff provides "Mail-In" crystallography service to users with the highest scored proposals. Both beamlines are equipped with very robust end-stations including on-axis visualization systems, Rayonix 300 CCD series detectors and Stanford-type robotic sample auto-mounters. MxDC, an in-house developed beamline control system, is integrated with a data processing module, AutoProcess, allowing full automation of data collection and data processing with minimal human intervention. Sample management and remote monitoring of experiments is enabled through interaction with a Laboratory Information Management System developed at the facility.
Mueller-Dieckmann, Christoph; Bowler, Matthew W.; Carpentier, Philippe; Flot, David; McCarthy, Andrew A.; Nanao, Max H.; Nurizzo, Didier; Pernot, Petra; Popov, Alexander; Round, Adam; Royant, Antoine; de Sanctis, Daniele; von Stetten, David; Leonard, Gordon A.
2015-04-01
The European Synchrotron Radiation Facility (ESRF) is the oldest and most powerful 3rd generation synchrotron in Europe, providing X-rays to more than 40 experimental stations welcoming several thousand researchers per year. A major success story has been the ESRF's facilities for macromolecular crystallography (MX). These are grouped around 3 straight sections: On ID23 canted undulators accommodate ID23-1, a mini-focus tuneable energy end station and ID23-2, the world's first micro-focus beamline dedicated to MX; ID29 houses a single, mini-focus, tuneable energy end station; ID30 will provide three end stations for MX due in operation from mid-2014 to early 2015. Here, one branch of a canted X-ray source feeds two fixed-energy end stations (MASSIF-1, MASSIF-3). The second feeds ID30B, a variable focus, tuneable energy beamline. MASSIF-1 is optimised for automatic high-throughput experiments requiring a relatively large beam size at the sample position, MASSIF-3 is a high-intensity, micro-focus facility designed to complement ID23-2. All end stations are highly automated, equipped with sample mounting robots and large area, fast-readout photon-counting detectors. Experiment control and tracking is achieved via a combination of the MXCuBE2 graphical user interface and the ISPyB database, the former allowing user-friendly control of all beamline components, the latter providing data tracking before, after and during experiments.
Triangulated manifold meshing method preserving molecular surface topology.
Chen, Minxin; Tu, Bin; Lu, Benzhuo
2012-09-01
Generation of manifold mesh is an urgent issue in mathematical simulations of biomolecule using boundary element methods (BEM) or finite element method (FEM). Defects, such as not closed mesh, intersection of elements and missing of small structures, exist in surface meshes generated by most of the current meshing method. Usually the molecular surface meshes produced by existing methods need to be revised carefully by third party software to ensure the surface represents a continuous manifold before being used in a BEM and FEM calculations. Based on the trace technique proposed in our previous work, in this paper, we present an improved meshing method to avoid intersections and preserve the topology of the molecular Gaussian surface. The new method divides the whole Gaussian surface into single valued pieces along each of x, y, z directions by tracing the extreme points along the fold curves on the surface. Numerical test results show that the surface meshes produced by the new method are manifolds and preserve surface topologies. The result surface mesh can also be directly used in surface conforming volume mesh generation for FEM type simulation. Copyright © 2012 Elsevier Inc. All rights reserved.
DELAUNAY TRIANGULATION METHOD OF CURVED SURFACES BASED ON RIEMANNIAN METRIC
Institute of Scientific and Technical Information of China (English)
无
2003-01-01
A method for quality mesh generation of parametric curved surfaces is proposed. It is shown that the main difference between the proposed method and previous ones is that our meshing process is done completely in the parametric domains with the guarantee of mesh quality. To obtain this aim, the Delaunay method is extended to anisotropic context of 2D domains, and a Riemannian metric map is introduced to remedy the mapping distortion from object space to parametric domain. Compared with previous algorithms, the approach is much simpler, more robust and speedy. The algorithm is implemented and examples for several geometries are presented to demonstrate the efficiency and validity of the method.
Cheng, Siu-Wing; Shewchuk, Jonathan
2013-01-01
Written by authors at the forefront of modern algorithms research, Delaunay Mesh Generation demonstrates the power and versatility of Delaunay meshers in tackling complex geometric domains ranging from polyhedra with internal boundaries to piecewise smooth surfaces. Covering both volume and surface meshes, the authors fully explain how and why these meshing algorithms work.The book is one of the first to integrate a vast amount of cutting-edge material on Delaunay triangulations. It begins with introducing the problem of mesh generation and describing algorithms for constructing Delaunay trian
Kuang, Xingyan; Dhroso, Andi; Han, Jing Ginger; Shyu, Chi-Ren; Korkin, Dmitry
2016-01-01
Macromolecular interactions are formed between proteins, DNA and RNA molecules. Being a principle building block in macromolecular assemblies and pathways, the interactions underlie most of cellular functions. Malfunctioning of macromolecular interactions is also linked to a number of diseases. Structural knowledge of the macromolecular interaction allows one to understand the interaction's mechanism, determine its functional implications and characterize the effects of genetic variations, such as single nucleotide polymorphisms, on the interaction. Unfortunately, until now the interactions mediated by different types of macromolecules, e.g. protein-protein interactions or protein-DNA interactions, are collected into individual and unrelated structural databases. This presents a significant obstacle in the analysis of macromolecular interactions. For instance, the homogeneous structural interaction databases prevent scientists from studying structural interactions of different types but occurring in the same macromolecular complex. Here, we introduce DOMMINO 2.0, a structural Database Of Macro-Molecular INteractiOns. Compared to DOMMINO 1.0, a comprehensive database on protein-protein interactions, DOMMINO 2.0 includes the interactions between all three basic types of macromolecules extracted from PDB files. DOMMINO 2.0 is automatically updated on a weekly basis. It currently includes ∼1,040,000 interactions between two polypeptide subunits (e.g. domains, peptides, termini and interdomain linkers), ∼43,000 RNA-mediated interactions, and ∼12,000 DNA-mediated interactions. All protein structures in the database are annotated using SCOP and SUPERFAMILY family annotation. As a result, protein-mediated interactions involving protein domains, interdomain linkers, C- and N- termini, and peptides are identified. Our database provides an intuitive web interface, allowing one to investigate interactions at three different resolution levels: whole subunit network
Mutation of torsion pairs in triangulated categories and its geometric realization
Zhou, Yu
2011-01-01
By generalizing mutation of rigid subcategories, maximal rigid subcategories and cluster tilting subcategories, the notion of mutation of torsion pairs in triangulated categories is introduced. It is proved that the mutation of torsion pairs in triangulated categories are torsion pairs. It is also proved that there is no non-trivial mutation of t-structures, but shift. A geometric realization of mutation of torsion pairs in the cluster categories of type $A_n$ or in the cluster categories of type $A_{\\infty}$ is given via the mutations (generalized flips) of Ptolemy diagrams of a regular $(n+3)-$gon $P_{n+3}$ or of a $\\infty-$gon $P_{\\infty}$ respectively.
Understanding how data triangulation identifies acute toxicity of novel psychoactive drugs.
Wood, D M; Dargan, P I
2012-09-01
Over the last decade, there has been an increase in the availability and use of novel psychoactive substances (also known as "legal highs"). There is limited information available on the potential acute toxicity (harms) associated with the use of these novel psychoactive substances. Gold standard evidence, such as animal studies or human clinical trials, is rarely available to users or healthcare professionals. However, it is possible to use triangulation of data on the acute toxicity from multiple sources to describe the overall pattern of toxicity associated with a novel psychoactive substance. In this review, we will describe these potential data sources, which include self-reported toxicity on internet discussion fora, data from sub-population user surveys, data from regional and national poisons information services and published case reports and case series. We will then describe how pattern of acute toxicity associated with the use of the cathinone mephedrone (4-methylmethcathinone) was established using triangulation of these different data sources.
Directory of Open Access Journals (Sweden)
GUO Peipei
2016-08-01
Full Text Available Building aggregation is an important part of research on large scale map generalization. A triangulation based approach is proposed from the perspective of shape features, six measure parameters of triangles in a constrained Delaunay triangulation are proposed. First of all, use the six measure parameters to determine which triangles are retained and which are erased. Then, the contours of retained triangles, as bridge areas between buildings, are automatically identified and right angle processed. And then, the buildings are aggregated with right angle feature retained by merging the bridge areas with connecting buildings. Finally, the approach is verified by being carried out on actual data. Experimental result shows that it is efficient and practical.
Drug repurposing by integrated literature mining and drug-gene-disease triangulation.
Sun, Peng; Guo, Jiong; Winnenburg, Rainer; Baumbach, Jan
2017-04-01
Drug design is expensive, time-consuming and becoming increasingly complicated. Computational approaches for inferring potentially new purposes of existing drugs, referred to as drug repositioning, play an increasingly important part in current pharmaceutical studies. Here, we first summarize recent developments in computational drug repositioning and introduce the utilized data sources. Afterwards, we introduce a new data fusion model based on n-cluster editing as a novel multi-source triangulation strategy, which was further combined with semantic literature mining. Our evaluation suggests that utilizing drug-gene-disease triangulation coupled to sophisticated text analysis is a robust approach for identifying new drug candidates for repurposing. Copyright © 2016 Elsevier Ltd. All rights reserved.
Non-contact luminescence lifetime cryothermometry for macromolecular crystallography.
Mykhaylyk, V B; Wagner, A; Kraus, H
2017-05-01
Temperature is a very important parameter when aiming to minimize radiation damage to biological samples during experiments that utilize intense ionizing radiation. A novel technique for remote, non-contact, in situ monitoring of the protein crystal temperature has been developed for the new I23 beamline at the Diamond Light Source, a facility dedicated to macromolecular crystallography (MX) with long-wavelength X-rays. The temperature is derived from the temperature-dependent decay time constant of luminescence from a minuscule scintillation sensor (luminescence lifetime thermometry is presented, the features of the detection method and the choice of temperature sensor are discussed, and it is demonstrated how the temperature monitoring system was integrated within the viewing system of the endstation used for the visualization of protein crystals. The thermometry system was characterized using a Bi4Ge3O12 crystal scintillator that exhibits good responsivity of the decay time constant as a function of temperature over a wide range (8-270 K). The scintillation sensor was calibrated and the uncertainty of the temperature measurements over the primary operation temperature range of the beamline (30-150 K) was assessed to be ±1.6 K. It has been shown that the temperature of the sample holder, measured using the luminescence sensor, agrees well with the expected value. The technique was applied to characterize the thermal performance of different sample mounts that have been used in MX experiments at the I23 beamline. The thickness of the mount is shown to have the greatest impact upon the temperature distribution across the sample mount. Altogether, these tests and findings demonstrate the usefulness of the thermometry system in highlighting the challenges that remain to be addressed for the in-vacuum MX experiment to become a reliable and indispensable tool for structural biology.
Nanometer-level axis of rotation metrology for a high-precision macromolecular X-ray diffractometer
Knapp, B.; Marsh, E.; Cipriani, F.; Arneson, D.; Oss, D.; Liebers, M.; Keller, E.
2013-03-01
The availability of micro-focused beams at 3rd generation synchrotrons makes collecting X-ray data from macromolecular crystals down to a fraction of micron size possible. This requires using goniometers with nanometer-level errors. Crystal positioning is typically realized with a multi-axis goniometer designed to minimize error motion during rotation of the crystal by the data-collection axis. In this paper, five degree-of-freedom error motions of an air bearing diffractometer data-collection axis are evaluated using a multiprobe method. As spindle errors and artifact out-of-roundness approach equal magnitudes, techniques must be used to distinguish and separate each error. A purpose-built fixture orients a single capacitive sensor in three asymmetrical positions to separate artifact form error from spindle error motion. Metrology results of this air bearing Omega spindle demonstrate synchronous errors of 16 nm radial, 4 nm axial and 0.28 μrad tilt.
Grishaev, Alexander; Guo, Liang; Irving, Thomas; Bax, Ad
2010-11-10
A new procedure, AXES, is introduced for fitting small-angle X-ray scattering (SAXS) data to macromolecular structures and ensembles of structures. By using explicit water models to account for the effect of solvent, and by restricting the adjustable fitting parameters to those that dominate experimental uncertainties, including sample/buffer rescaling, detector dark current, and, within a narrow range, hydration layer density, superior fits between experimental high resolution structures and SAXS data are obtained. AXES results are found to be more discriminating than standard Crysol fitting of SAXS data when evaluating poorly or incorrectly modeled protein structures. AXES results for ensembles of structures previously generated for ubiquitin show improved fits over fitting of the individual members of these ensembles, indicating these ensembles capture the dynamic behavior of proteins in solution.
Nther-type theorem of piecewise algebraic curves on triangulation
Institute of Scientific and Technical Information of China (English)
2007-01-01
The piecewise algebraic curve is a kind generalization of the classical algebraic curve. Nther-type theorem of piecewise algebraic curves on the cross-cut partition is very important to construct the Lagrange interpolation sets for a bivariate spline space.In this paper,using the properties of bivariate splines,the Nther-type theorem of piecewise algebraic curves on the arbitrary triangulation is presented.
Meedy Nugraha
2002-01-01
This paper proposes the importance of multiple instrumentation and data source (triangulation) in a needs analysis. Various data gathering methods developed in assessing learners' English language needs are reviewed. The justification of employing more than a single data gathering method and data source in a needs analysis is also presented by examining the strengths and weaknesses of each method and evaluating previous needs analyses carried out in some Asian countries. Highlights are then g...
Coarse error analysis and correction of a two-dimensional triangulation range finder
Institute of Scientific and Technical Information of China (English)
Huaqiao Gui; Liang Lü; Wei Huang; Jun Xu; Deyong He; Huanqin Wang; Jianping Xie; Tianpeng Zhao; Hai Ming
2006-01-01
@@ A real-time two-dimensional (2D) triangulation range finder is presented, which is composed of two linear complementary metal oxidation semiconductor (CMOS) chips, two camera lenses, and four light emitting diodes (LEDs). The high order distortion in image aberrations is the main factor responsible for the coarse errors. The theoretical prediction is in good agreement with experiments and the correction equation is used to obtain more reliable results with the unique distortion coefficient in the whole working region.
Chen, Jun; Luo, Chaomin; Krishnan, Mohan; Paulik, Mark; Tang, Yipeng
2010-01-01
An enhanced dynamic Delaunay Triangulation-based (DT) path planning approach is proposed for mobile robots to plan and navigate a path successfully in the context of the Autonomous Challenge of the Intelligent Ground Vehicle Competition (www.igvc.org). The Autonomous Challenge course requires the application of vision techniques since it involves path-based navigation in the presence of a tightly clustered obstacle field. Course artifacts such as switchbacks, ramps, dashed lane lines, trap etc. are present which could turn the robot around or cause it to exit the lane. The main contribution of this work is a navigation scheme based on dynamic Delaunay Triangulation (DDT) that is heuristically enhanced on the basis of a sense of general lane direction. The latter is computed through a "GPS (Global Positioning System) tail" vector obtained from the immediate path history of the robot. Using processed data from a LADAR, camera, compass and GPS unit, a composite local map containing both obstacles and lane line segments is built up and Delaunay Triangulation is continuously run to plan a path. This path is heuristically corrected, when necessary, by taking into account the "GPS tail" . With the enhancement of the Delaunay Triangulation by using the "GPS tail", goal selection is successfully achieved in a majority of situations. The robot appears to follow a very stable path while navigating through switchbacks and dashed lane line situations. The proposed enhanced path planning and GPS tail technique has been successfully demonstrated in a Player/Stage simulation environment. In addition, tests on an actual course are very promising and reveal the potential for stable forward navigation.
Zhang, Guojie; Zhang,Pei; Krawczak, Michael; Ball, Edward V.; Mort, Matthew; Kehrer-Sawatzki, Hildegard; Cooper, David N.
2010-01-01
Abstract Triangulation of the human, chimpanzee and Neanderthal genome sequences with respect to 44,348 disease-causing or disease-associated missense mutations and 1,712 putative regulatory mutations listed in the Human Gene Mutation Database was employed to identify genetic variants that are apparently pathogenic in humans but which may represent a `compensated? wild-type state in at least one of the other two species. Of 122 such `potentially compensated mutations? (PCMs) identi...
Chromatic Sums of Biloopless Nonseparable Near-Triangulations on the Projective Plane
Institute of Scientific and Technical Information of China (English)
Zhao-xiang Li; Yan-pei Liu; Bing-feng Si
2013-01-01
In this paper,the chromatic sum functions of rooted biloopless nonseparable near-triangulations on the sphere and the projective plane are studied.The chromatic sum function equations of such maps are obtained.From the chromatic sum equations of such maps,the enumerating function equations of such maps are derived.An asymptotic evaluation and some explicit expression of enumerating functions are also derived.
平面域中的Delaunay三角算法%Delaunay Triangulation Algorithm in Planar Domain
Institute of Scientific and Technical Information of China (English)
张洁; 陈世元
2007-01-01
对目前广泛使用的Delaunay三角网格生成方法的基本原理进行阐述,对目前流行的几类DT(Delaunay Triangulation)算法,逐点插入算法、分治算法、三角网生长算法的原理进行了分析,对它们的特点进行了介绍.
N(o)ther-type theorem of piecewise algebraic curves on triangulation
Institute of Scientific and Technical Information of China (English)
Chun-gang ZHU; Ren-hong WANG
2007-01-01
The piecewise algebraic curve is a kind generalization of the classical algebraic curve.N(o)ther-type theorem of piecewise algebraic curves on the cross-cut partition is very important to construct the Lagrange interpolation sets for a bivariate spline space. In this paper, using the properties of bivariate splines, the N(o)ther-type theorem of piecewise algebraic curves on the arbitrary triangulation is presented.
A triangulation of a homotopy-Deligne-Mumford compactification of the Moduli of curves
Gadgil, Siddhartha
2010-01-01
We construct a triangulation of a compactification of the Moduli space of a surface with at least one puncture that is closely related to the Deligne-Mumford compactification. Specifically, there is a surjective map from the compactification we construct to the Deligne-Mumford compactification so that the inverse image of each point is contractible. In particular our compactification is homotopy equivalent to the Deligne-Mumford compactification.
Rutherford, George W; McFarland, William; Spindler, Hilary; White, Karen; Patel, Sadhna V; Aberle-Grasse, John; Sabin, Keith; Smith, Nathan; Taché, Stephanie; Calleja-Garcia, Jesus M; Stoneburner, Rand L
2010-07-29
Public health triangulation is a process for reviewing, synthesising and interpreting secondary data from multiple sources that bear on the same question to make public health decisions. It can be used to understand the dynamics of HIV transmission and to measure the impact of public health programs. While traditional intervention research and meta-analysis would be ideal sources of information for public health decision making, they are infrequently available, and often decisions can be based only on surveillance and survey data. The process involves examination of a wide variety of data sources and both biological, behavioral and program data and seeks input from stakeholders to formulate meaningful public health questions. Finally and most importantly, it uses the results to inform public health decision-making. There are 12 discrete steps in the triangulation process, which included identification and assessment of key questions, identification of data sources, refining questions, gathering data and reports, assessing the quality of those data and reports, formulating hypotheses to explain trends in the data, corroborating or refining working hypotheses, drawing conclusions, communicating results and recommendations and taking public health action. Triangulation can be limited by the quality of the original data, the potentials for ecological fallacy and "data dredging" and reproducibility of results. Nonetheless, we believe that public health triangulation allows for the interpretation of data sets that cannot be analyzed using meta-analysis and can be a helpful adjunct to surveillance, to formal public health intervention research and to monitoring and evaluation, which in turn lead to improved national strategic planning and resource allocation.
Directory of Open Access Journals (Sweden)
Aberle-Grasse John
2010-07-01
Full Text Available Abstract Background Public health triangulation is a process for reviewing, synthesising and interpreting secondary data from multiple sources that bear on the same question to make public health decisions. It can be used to understand the dynamics of HIV transmission and to measure the impact of public health programs. While traditional intervention research and metaanalysis would be ideal sources of information for public health decision making, they are infrequently available, and often decisions can be based only on surveillance and survey data. Methods The process involves examination of a wide variety of data sources and both biological, behavioral and program data and seeks input from stakeholders to formulate meaningful public health questions. Finally and most importantly, it uses the results to inform public health decision-making. There are 12 discrete steps in the triangulation process, which included identification and assessment of key questions, identification of data sources, refining questions, gathering data and reports, assessing the quality of those data and reports, formulating hypotheses to explain trends in the data, corroborating or refining working hypotheses, drawing conclusions, communicating results and recommendations and taking public health action. Results Triangulation can be limited by the quality of the original data, the potentials for ecological fallacy and "data dredging" and reproducibility of results. Conclusions Nonetheless, we believe that public health triangulation allows for the interpretation of data sets that cannot be analyzed using meta-analysis and can be a helpful adjunct to surveillance, to formal public health intervention research and to monitoring and evaluation, which in turn lead to improved national strategic planning and resource allocation.
SUPERCONVERGENCE OF LEAST-SQUARES MIXED FINITE ELEMENTS FOR ELLIPTIC PROBLEMS ON TRIANGULATION
Institute of Scientific and Technical Information of China (English)
陈艳萍; 杨菊娥
2003-01-01
In this paper,we present the least-squares mixed finite element method and investigate superconvergence phenomena for the second order elliptic boundary-value problems over triangulations.On the basis of the L2-projection and some mixed finite element projections,we obtain the superconvergence result of least-squares mixed finite element solutions.This error estimate indicates an accuracy of O(h3/2)if the lowest order Raviart-Thomas elements are employed.
Kammerer, Yvonne; Jarodzka, Halszka
2011-01-01
Kammerer, Y., & Jarodzka, H. (2010, September). Das Auge als Datenquelle: Triangulation von Blickbewegungsdaten zur Analyse perzeptueller und kognitiver Prozesse in der angewandten Psychologie. Arbeitsgruppe auf dem 47. Kongress der Deutschen Gesellschaft für Psychologie (DGPs). Bremen.
Triangulated Irregular Networks (TIN), Published in 2005, 1:600 (1in=50ft) scale, Oconto County.
NSGIC GIS Inventory (aka Ramona) — This Triangulated Irregular Networks (TIN) dataset, published at 1:600 (1in=50ft) scale, was produced all or in part from LIDAR information as of 2005. Data by this...
NSGIC GIS Inventory (aka Ramona) — This Triangulated Irregular Networks (TIN) dataset, published at 1:24000 (1in=2000ft) scale, was produced all or in part from Orthoimagery information as of 2008....
NSGIC GIS Inventory (aka Ramona) — This Triangulated Irregular Networks (TIN) dataset, published at 1:1200 (1in=100ft) scale, was produced all or in part from Orthoimagery information as of 2000....
Bergasa-Caceres, Fernando; Rabitz, Herschel A.
2013-06-01
A model of protein folding kinetics is applied to study the effects of macromolecular crowding on protein folding rate and stability. Macromolecular crowding is found to promote a decrease of the entropic cost of folding of proteins that produces an increase of both the stability and the folding rate. The acceleration of the folding rate due to macromolecular crowding is shown to be a topology-dependent effect. The model is applied to the folding dynamics of the murine prion protein (121-231). The differential effect of macromolecular crowding as a function of protein topology suffices to make non-native configurations relatively more accessible.
Energy Technology Data Exchange (ETDEWEB)
Golin, M.J. [Hong Kong Univ. of Science and Technology, Kowloon (Hong Kong)
1996-12-31
Let MWT(n) be the weight of a minimum-weight triangulation of n points chosen independently from the uniform distribution over [0, 1]{sup 2}. Previous work has shown that E(MWT(n)) = {Theta} ({radical}n). In this paper we develop techniques for proving that MWT(n)/{radical}n actually converges to a constant in both expectation and in probability. An immediate consequence is the development of an O(n{sup 2}) time algorithm that finds a triangulation whose competive ratio with the MWT is, in a probabilistic sense, exactly one. The techniques developed to prove the above results are quite general and can also prove the convergence of certain types of probabilistic recurrence equations and other Euclidean Functionals. This is illustrated by using them to prove the convergence of the weight of MWTs of random points in higher dimensions and a sketch of how to use them to prove the convergence of the degree probabilities for Delaunay triangulations in {Re}{sup 2}.
The triangulation of the gigantic jets observed by the optical observation network in Taiwan
Chen, Alfred B.; Huang, Chien-Fong; Peng, Kang-Ming; Su, Han-Tzong; Hsu, Rue-Ron
2015-04-01
The optical triangulation of sprites and elves by the multiple sites has been done in the past decades, but the similar observation on gigantic jets has never been reported yet. A ground optical observation network consisting of four stations at Kimen, Penghu, Tainan, and Taitung (from west to east) has been established in Taiwan since 2012. Each station equipped with two sets of Watec low-light sensitivity cameras, and the elevation and azimuth of the observation can be fully remote controlled to point toward the on-going convection system in the vicinity of Taiwan. In summer 2014, more than 6 gigantic jets were captured by at least two stations successfully. The triangulation and ULF sferics of these interesting events provides an excellent chance to explore the spatial and temporal evolution of the jets in different phases. In this presentation, this ground observation network will be introduced, the detail evolution of the recorded gigantic jets is presented. The preliminary result implies that the jets may not pop from the cloudtop straightforwardly, and some twists occur during the propagation of the jets. A more complicated analysis of the tomography for the advanced triangulation will be mentioned, too.
Selecting the aspect ratio of a scatter plot based on its delaunay triangulation.
Fink, Martin; Haunert, Jan-Henrik; Spoerhase, Joachim; Wolff, Alexander
2013-12-01
Scatter plots are diagrams that visualize two-dimensional data as sets of points in the plane. They allow users to detect correlations and clusters in the data. Whether or not a user can accomplish these tasks highly depends on the aspect ratio selected for the plot, i.e., the ratio between the horizontal and the vertical extent of the diagram. We argue that an aspect ratio is good if the Delaunay triangulation of the scatter plot at this aspect ratio has some nice geometric property, e.g., a large minimum angle or a small total edge length. More precisely, we consider the following optimization problem. Given a set Q of points in the plane, find a scale factor s such that scaling the x-coordinates of the points in Q by s and the y-coordinates by 1=s yields a point set P(s) that optimizes a property of the Delaunay triangulation of P(s), over all choices of s. We present an algorithm that solves this problem efficiently and demonstrate its usefulness on real-world instances. Moreover, we discuss an empirical test in which we asked 64 participants to choose the aspect ratios of 18 scatter plots. We tested six different quality measures that our algorithm can optimize. In conclusion, minimizing the total edge length and minimizing what we call the 'uncompactness' of the triangles of the Delaunay triangulation yielded the aspect ratios that were most similar to those chosen by the participants in the test.
Durif-Bruckert, C; Roux, P; Morelle, M; Mignotte, H; Faure, C; Moumjid-Ferdjaoui, N
2015-07-01
The aim of this study on shared decision-making in the doctor-patient encounter about surgical treatment for early-stage breast cancer, conducted in a regional cancer centre in France, was to further the understanding of patient perceptions on shared decision-making. The study used methodological triangulation to collect data (both quantitative and qualitative) about patient preferences in the context of a clinical consultation in which surgeons followed a shared decision-making protocol. Data were analysed from a multi-disciplinary research perspective (social psychology and health economics). The triangulated data collection methods were questionnaires (n = 132), longitudinal interviews (n = 47) and observations of consultations (n = 26). Methodological triangulation revealed levels of divergence and complementarity between qualitative and quantitative results that suggest new perspectives on the three inter-related notions of decision-making, participation and information. Patients' responses revealed important differences between shared decision-making and participation per se. The authors note that subjecting patients to a normative behavioural model of shared decision-making in an era when paradigms of medical authority are shifting may undermine the patient's quest for what he or she believes is a more important right: a guarantee of the best care available.
Using GPS/INS data to enhance image matching for real-time aerial triangulation
Tanathong, Supannee; Lee, Impyeong
2014-11-01
Direct georeferencing is a promising technique for determining the exterior orientation parameters (EO) of a camera in real-time through the integration of GPS/INS sensors. Instead of using expensive devices, we improve the accuracy of the directly measured EOs through aerial triangulation (AT) and rely on tie-points. In this work, using GPS/INS data, we enhance the KLT tracker to achieve accuracy and speed that is compatible with real-time aerial triangulation. Given GPS/INS data from medium-grade sensors, the proposed system is 48% faster than the original work and tie-points extracted by our system are 6.33% more accurate and more evenly distributed than tie-points extracted by the original work. The AT processing results show that tie-points from the proposed work can reduce the RMSE of the directly measured EOs by 17.87% for position and 23.37% for attitude. Thus, we conclude that our proposed system can be integrated with real-time aerial triangulation.
Chromatic polynomials of planar triangulations, the Tutte upper bound and chromatic zeros
Shrock, Robert; Xu, Yan
2012-02-01
Tutte proved that if Gpt is a planar triangulation and P(Gpt, q) is its chromatic polynomial, then |P(Gpt, τ + 1)| ⩽ (τ - 1)n - 5, where \\tau =(1+\\sqrt{5} \\, )/2 and n is the number of vertices in Gpt. Here we study the ratio r(Gpt) = |P(Gpt, τ + 1)|/(τ - 1)n - 5 for a variety of planar triangulations. We construct infinite recursive families of planar triangulations Gpt, m depending on a parameter m linearly related to n and show that if P(Gpt, m, q) only involves a single power of a polynomial, then r(Gpt, m) approaches zero exponentially fast as n → ∞. We also construct infinite recursive families for which P(Gpt, m, q) is a sum of powers of certain functions and show that for these, r(Gpt, m) may approach a finite nonzero constant as n → ∞. The connection between the Tutte upper bound and the observed chromatic zero(s) near to τ + 1 is investigated. We report the first known graph for which the zero(s) closest to τ + 1 is not real, but instead is a complex-conjugate pair. Finally, we discuss connections with the nonzero ground-state entropy of the Potts antiferromagnet on these families of graphs.
Indian Academy of Sciences (India)
R Sharma; O P Sha
2006-10-01
Design of fair surfaces over irregular domains is a fundamental problem in computer-aided geometric design (CAGD), and has applications in engineering sciences (in aircraft, automobile, ship science etc.). In the design of fair surfaces over irregular domains deﬁned over scattered data, it was widely accepted till recently that the classical Delaunay triangulation be used because of its global optimum property. However, in recent times it has been shown that for continuous piecewise linear surfaces, improvements in the quality of ﬁt can be achieved if the triangulation pattern is made dependent upon some topological or geometric property of the data set or is simply data dependent. The fair surface is desired because it ensures smooth and continuous surface planar cuts, and these in turn ensure smooth and easy production of the surface in CAD/CAM, and favourable resistance properties. In this paper, we discuss a method for construction of $C^1$ piecewise polynomial parametric fair surfaces which interpolate prescribed $\\mathfrak{R}^3$ scattered data using spaces of parametric splines deﬁned on $\\mathfrak{R}^3$ triangulation. We show that our method is more speciﬁc to the cases when the projection on a 2-D plane may consist of triangles of zero area, numerically stable and robust, and computationally inexpensive and fast. Numerical examples dealing with surfaces approximated on plates, and on ships have been presented.
Computational Modeling for What-Is, What-Might-Be,and What-Should-Be Studies—And Triangulation
DEFF Research Database (Denmark)
Burton, Richard M.; Obel, Børge
2011-01-01
In this essay, we examine what-is, what-might-be, and what-should-be computational models where the purpose is to explore new concepts, ideas, boundaries, and limitations going beyond what we know at the moment. Computational models complement well with other approaches: ethnographies, field stud...... studies, human subject lab studies, and surveys in novel triangulations. Triangulation of two or more complementary approaches permits us to broaden and deepen our understanding and insights....
Peleg, Ora
2014-12-01
This study examined the relationships between stressful life events in childhood and differentiation of self and intergenerational triangulation in adulthood. The sample included 217 students (173 females and 44 males) from a college in northern Israel. Participants completed the Hebrew versions of Life Events Checklist (LEC), Differentiation of Self Inventory-Revised (DSI-R) and intergenerational triangulation (INTRI). The main findings were that levels of stressful life events during childhood and adolescence among both genders were positively correlated with the levels of fusion with others and intergenerational triangulation. The levels of positive life events were negatively related to levels of emotional reactivity, emotional cut-off and intergenerational triangulation. Levels of stressful life events in females were positively correlated with emotional reactivity. Intergenerational triangulation was correlated with emotional reactivity, emotional cut-off, fusion with others and I-position. Findings suggest that families that experience higher levels of stressful life events may be at risk for higher levels of intergenerational triangulation and lower levels of differentiation of self.
Directory of Open Access Journals (Sweden)
Julian C.-H. Chen
2017-01-01
Full Text Available The Protein Crystallography Station (PCS, located at the Los Alamos Neutron Scattering Center (LANSCE, was the first macromolecular crystallography beamline to be built at a spallation neutron source. Following testing and commissioning, the PCS user program was funded by the Biology and Environmental Research program of the Department of Energy Office of Science (DOE-OBER for 13 years (2002–2014. The PCS remained the only dedicated macromolecular neutron crystallography station in North America until the construction and commissioning of the MaNDi and IMAGINE instruments at Oak Ridge National Laboratory, which started in 2012. The instrument produced a number of research and technical outcomes that have contributed to the field, clearly demonstrating the power of neutron crystallography in helping scientists to understand enzyme reaction mechanisms, hydrogen bonding and visualization of H-atom positions, which are critical to nearly all chemical reactions. During this period, neutron crystallography became a technique that increasingly gained traction, and became more integrated into macromolecular crystallography through software developments led by investigators at the PCS. This review highlights the contributions of the PCS to macromolecular neutron crystallography, and gives an overview of the history of neutron crystallography and the development of macromolecular neutron crystallography from the 1960s to the 1990s and onwards through the 2000s.
Chen, Julian C-H; Unkefer, Clifford J
2017-01-01
The Protein Crystallography Station (PCS), located at the Los Alamos Neutron Scattering Center (LANSCE), was the first macromolecular crystallography beamline to be built at a spallation neutron source. Following testing and commissioning, the PCS user program was funded by the Biology and Environmental Research program of the Department of Energy Office of Science (DOE-OBER) for 13 years (2002-2014). The PCS remained the only dedicated macromolecular neutron crystallography station in North America until the construction and commissioning of the MaNDi and IMAGINE instruments at Oak Ridge National Laboratory, which started in 2012. The instrument produced a number of research and technical outcomes that have contributed to the field, clearly demonstrating the power of neutron crystallo-graphy in helping scientists to understand enzyme reaction mechanisms, hydrogen bonding and visualization of H-atom positions, which are critical to nearly all chemical reactions. During this period, neutron crystallography became a technique that increasingly gained traction, and became more integrated into macromolecular crystallography through software developments led by investigators at the PCS. This review highlights the contributions of the PCS to macromolecular neutron crystallography, and gives an overview of the history of neutron crystallography and the development of macromolecular neutron crystallography from the 1960s to the 1990s and onwards through the 2000s.
Marín-Yaseli, Margarita R; Cid, Cristina; Yagüe, Ana I; Ruiz-Bermejo, Marta
2017-02-01
Elucidating the origin of life involves synthetic as well as analytical challenges. Herein, for the first time, we describe the use of gel electrophoresis and ultrafiltration to fractionate HCN polymers. Since the first prebiotic synthesis of adenine by Oró, HCN polymers have gained much interest in studies on the origins of life due to the identification of biomonomers and related compounds within them. Here, we demonstrate that macromolecular fractions with electrophoretic mobility can also be detected within HCN polymers. The migration of polymers under the influence of an electric field depends not only on their sizes (one-dimensional electrophoresis) but also their different isoelectric points (two-dimensional electrophoresis, 2-DE). The same behaviour was observed for several macromolecular fractions detected in HCN polymers. Macromolecular fractions with apparent molecular weights as high as 250 kDa were detected by tricine-SDS gel electrophoresis. Cationic macromolecular fractions with apparent molecular weights as high as 140 kDa were also detected by 2-DE. The HCN polymers synthesized were fractionated by ultrafiltration. As a result, the molecular weight distributions of the macromolecular fractions detected in the HCN polymers directly depended on the synthetic conditions used to produce these polymers. The implications of these results for prebiotic chemistry will be discussed.
Directory of Open Access Journals (Sweden)
jean yves fourniols
2013-02-01
Full Text Available This work focus on the structural health monitoring of aircrafts parts specimen structures made of 2024 Aluminum alloys using a reliable Joint Time Frequency Analysis calculation (Joint Temporal Frequency Analysis. In this paper we demonstrate the feasibility of a new non destructive control method capable to probe very large structures within a short time. The method we developed is based through a wide piezoelectric sensors network on a smart comparison between two acoustic signatures: the healthy structure response captured before the commissioning of the plane and “an after flight” response. The sensors network exploits the capability of piezoelectric patches to generate/measure specific Lamb wave’s modes. The system is therefore dynamically configured to localize mechanicals flaws using a triangulation algorithm that operates using different techniques like pitch-catch and pulse-echo. The aim of this paper is to highlight a methodology that is currently being integrated into reconfigurable qualified and certified hardware architecture. The idea behind is to interface the airplane's structure to an integrated modular avionics calculator (IMA.An analytic study is performed and tests to prove the proposed method feasibility on corroded and damaged structures specimens are provided at the end of this paper.
Institute of Scientific and Technical Information of China (English)
Hai Yan Zhang; Xing Ying Zhang
2009-01-01
A new kind of multifunctional macromolecular initiator with Sn-C bonds and polydiene arms was synthesized by living anionic polymerization.At first,polydiene-stannum chloride(PD-SnCl3)was prepared by the reaction of n-butyl-Li(n-BuLi),stannic chloride(SnCl4)and diene.Then PD-SnCl3 was used to react with the dilithium initiator to prepare the multifunctional organic macromolecular initiators.The result suggested that the initiators had a remarkable yield by GPC,nearly 90%.By using these multifunctional macromolecular initiators,styrene and butadiene were effectively polymerized via anionic polymerization,which gave birth to novel miktoarm star copolymers.The relative molecular weight and polydispersity index,microstructure contents,copolymerization components,glass transition temperature(Tg)and morphology of the miktoarm star copolymers were investigated by GPC-UV,1H NMR,DSC and TEM,respectively.
Use of Site-Specifically Tethered Chemical Nucleases to Study Macromolecular Reactions
Directory of Open Access Journals (Sweden)
Mukherjee Srabani
2003-01-01
Full Text Available During a complex macromolecular reaction multiple changes in molecular conformation and interactions with ligands may occur. X-ray crystallography may provide only a limited set of snapshots of these changes. Solution methods can augment such structural information to provide a more complete picture of a macromolecular reaction. We analyzed the changes in protein conformation and protein:nucleic acid interactions which occur during transcription initiation by using a chemical nuclease tethered to cysteines introduced site-specifically into the RNA polymerase of bacteriophage T7 (T7 RNAP. Changes in cleavage patterns as the polymerase steps through transcription reveal a series of structural transitions which mediate transcription initiation. Cleavage by tethered chemical nucleases is seen to be a powerful method for revealing the conformational dynamics of macromolecular reactions, and has certain advantages over cross-linking or energy transfer approaches.
Macromolecular Hydrogen Sulfide Donors Trigger Spatiotemporally Confined Changes in Cell Signaling.
Ercole, Francesca; Mansfeld, Friederike M; Kavallaris, Maria; Whittaker, Michael R; Quinn, John F; Halls, Michelle L; Davis, Thomas P
2016-01-11
Hydrogen sulfide (H2S) is involved in a myriad of cell signaling processes that trigger physiological events ranging from vasodilation to cell proliferation. Moreover, disturbances to H2S signaling have been associated with numerous pathologies. As such, the ability to release H2S in a cellular environment and stimulate signaling events is of considerable interest. Herein we report the synthesis of macromolecular H2S donors capable of stimulating cell signaling pathways in both the cytosol and at the cell membrane. Specifically, copolymers having pendent oligo(ethylene glycol) and benzonitrile groups were synthesized, and the benzonitrile groups were subsequently transformed into primary aryl thioamide groups via thionation using sodium hydrosulfide. These thioamide moieties could be incorporated into a hydrophilic copolymer or a block copolymer (i.e., into either the hydrophilic or hydrophobic domain). An electrochemical sensor was used to demonstrate release of H2S under simulated physiological conditions. Subsequent treatment of HEK293 cells with a macromolecular H2S donor elicited a slow and sustained increase in cytosolic ERK signaling, as monitored using a FRET-based biosensor. The macromolecular donor was also shown to induce a small, fast and sustained increase in plasma membrane-localized PKC activity immediately following addition to cells. Studies using an H2S-selective fluorescent probe in live cells confirmed release of H2S from the macromolecular donor over physiologically relevant time scales consistent with the signaling observations. Taken together, these results demonstrate that by using macromolecular H2S donors it is possible to trigger spatiotemporally confined cell signaling events. Moreover, the localized nature of the observed signaling suggests that macromolecular donor design may provide an approach for selectively stimulating certain cellular biochemical pathways.
The Joint Structural Biology Group beam lines at the ESRF: Modern macromolecular crystallography
Mitchell, E P
2001-01-01
Macromolecular crystallography has evolved considerably over the last decade. Data sets in under an hour are now possible on high throughput beam lines leading to electron density and, possibly, initial models calculated on-site. There are five beam lines currently dedicated to macromolecular crystallography: the ID14 complex and BM-14 (soon to be superseded by ID-29). These lines handle over five hundred projects every six months and demand is increasing. Automated sample handling, alignment and data management protocols will be required to work efficiently with this demanding load. Projects developing these themes are underway within the JSBG.
Energy Technology Data Exchange (ETDEWEB)
Nagata, Tetsuji [Shinshu University, Matsumoto (Japan). Dept. of Anatomy and Cell Biology
2007-07-01
This mini-review reports aging changes of macromolecular synthesis in the mitochondria of mouse hepatocytes. We have observed the macromolecular synthesis, such as DNA, RNA and proteins, in the mitochondria of various mammalian cells by means of electron microscopic radioautography technique developed in our laboratory. The number of mitochondria per cell, number of labeled mitochondria per cell with 3H-thymidine, 3H-uridine and 3H-leucine, precursors for DNA, RNA and proteins, respectively, were counted and the labeling indices at various ages, from fetal to postnatal early days and several months to 1 and 2 years in senescence, were calculated, which showed variations due to aging. (author)
THE STEADY/PULSATILE FLOW AND MACROMOLECULAR TRANSPORT IN T-BIFURCATION BLOOD VESSELS
Institute of Scientific and Technical Information of China (English)
李丁; 温功碧
2003-01-01
A numerical analysis of the steady and pulsatile, macromolecular( such as lowdensity lipopotein ( LDL ), Albumin ) transport in T-bifurcation was proposed. Theinfluence of Reynolds number and mass flow ratio etc. parameters on the velocity field andmass transport were calculated. The computational results predict that the blood flow factorsaffect the macromolecular distribution and the transport across the wall, it shows thathemodynamic play an important role in the process of atherosclerosis . The LDL and Albuminconcentration on the wall varies most greatly in flow bifurcation area where the wall shearstress varies greatly at the branching vessel and the atherosclerosis often appears there.
Accounting for large amplitude protein deformation during in silico macromolecular docking.
Bastard, Karine; Saladin, Adrien; Prévost, Chantal
2011-02-22
Rapid progress of theoretical methods and computer calculation resources has turned in silico methods into a conceivable tool to predict the 3D structure of macromolecular assemblages, starting from the structure of their separate elements. Still, some classes of complexes represent a real challenge for macromolecular docking methods. In these complexes, protein parts like loops or domains undergo large amplitude deformations upon association, thus remodeling the surface accessible to the partner protein or DNA. We discuss the problems linked with managing such rearrangements in docking methods and we review strategies that are presently being explored, as well as their limitations and success.
Influence of protein crowder size on hydration structure and dynamics in macromolecular crowding
Wang, Po-hung; Yu, Isseki; Feig, Michael; Sugita, Yuji
2017-03-01
We investigate the effects of protein crowder sizes on hydration structure and dynamics in macromolecular crowded systems by all-atom MD simulations. The crowded systems consisting of only small proteins showed larger total surface areas than those of large proteins at the same volume fractions. As a result, more water molecules were trapped within the hydration shells, slowing down water diffusion. The simulation results suggest that the protein crowder size is another factor to determine the effect of macromolecular crowding and to explain the experimental kinetic data of proteins and DNAs in the presence of crowding agents.
Accounting for Large Amplitude Protein Deformation during in Silico Macromolecular Docking
Bastard, Karine; Saladin, Adrien; Prévost, Chantal
2011-01-01
Rapid progress of theoretical methods and computer calculation resources has turned in silico methods into a conceivable tool to predict the 3D structure of macromolecular assemblages, starting from the structure of their separate elements. Still, some classes of complexes represent a real challenge for macromolecular docking methods. In these complexes, protein parts like loops or domains undergo large amplitude deformations upon association, thus remodeling the surface accessible to the partner protein or DNA. We discuss the problems linked with managing such rearrangements in docking methods and we review strategies that are presently being explored, as well as their limitations and success. PMID:21541061
Accounting for Large Amplitude Protein Deformation during in Silico Macromolecular Docking
Directory of Open Access Journals (Sweden)
Chantal Prévost
2011-02-01
Full Text Available Rapid progress of theoretical methods and computer calculation resources has turned in silico methods into a conceivable tool to predict the 3D structure of macromolecular assemblages, starting from the structure of their separate elements. Still, some classes of complexes represent a real challenge for macromolecular docking methods. In these complexes, protein parts like loops or domains undergo large amplitude deformations upon association, thus remodeling the surface accessible to the partner protein or DNA.We discuss the problems linked with managing such rearrangements in docking methods and we review strategies that are presently being explored, as well as their limitations and success.
Phase Sensitive X-Ray Diffraction Imaging of Defects in Biological Macromolecular Crystals
Hu, Z. W.; Lai, B.; Chu, Y. S.; Cai, Z.; Mancini, D. C.; Thomas, B. R.; Chernov, A. A.; Curreri, Peter A. (Technical Monitor)
2002-01-01
Characterization of defects and/or disorder in biological macromolecular crystals presents much greater challenges than in conventional small-molecule crystals. The lack of sufficient contrast of defects is often a limiting factor in x-ray diffraction topography of protein crystals. This has seriously hampered efforts to understand mechanisms and origins of formation of imperfections, and the role of defects as essential entities in the bulk of macromolecular crystals. In this report, we employ a phase sensitive x-ray diffraction imaging approach for augmenting the contrast of defects in protein crystals.
Poly(isophthalic acid)(ethylene oxide) as a Macromolecular Modulator for Metal-Organic Polyhedra.
Chen, Teng-Hao; Wang, Le; Trueblood, Jonathan V; Grassian, Vicki H; Cohen, Seth M
2016-08-03
A new strategy was developed by using a polymer ligand, poly(isophthalic acid)(ethylene oxide), to modulate the growth of metal-organic polyhedra (MOP) crystals. This macromolecular modulator can effectively control the crystal habit of several different Cu24L24 (L = isophthalic acid derivatives) MOPs. The polymer also directed the formation of MOP structures under reaction conditions that only produce metal-organic frameworks in the absence of modulator. Moreover, the polymer also enabled the deposition of MOP crystals on glass surfaces. This macromolecular modulator strategy provides an innovative approach to control the morphology and assembly of MOP particles.
Effect of macromolecular crowding on the rate of diffusion-limited enzymatic reaction
Indian Academy of Sciences (India)
Manish Agrawal; S B Santra; Rajat Anand; Rajaram Swaminathan
2008-08-01
The cytoplasm of a living cell is crowded with several macromolecules of different shapes and sizes. Molecular diffusion in such a medium becomes anomalous due to the presence of macromolecules and diffusivity is expected to decrease with increase in macromolecular crowding. Moreover, many cellular processes are dependent on molecular diffusion in the cell cytosol. The enzymatic reaction rate has been shown to be affected by the presence of such macromolecules. A simple numerical model is proposed here based on percolation and diffusion in disordered systems to study the effect of macromolecular crowding on the enzymatic reaction rates. The model qualitatively explains some of the experimental observations.
Shimizu, Nobutaka; Shimizu, Tetsuya; Baba, Seiki; Hasegawa, Kazuya; Yamamoto, Masaki; Kumasaka, Takashi
2013-11-01
Measurement of the UV-visible absorption spectrum is a convenient technique for detecting chemical changes of proteins, and it is therefore useful to combine spectroscopy and diffraction studies. An online microspectrophotometer for the UV-visible region was developed and installed on the macromolecular crystallography beamline, BL38B1, at SPring-8. This spectrophotometer is equipped with a difference dispersive double monochromator, a mercury-xenon lamp as the light source, and a photomultiplier as the detector. The optical path is mostly constructed using mirrors, in order to obtain high brightness in the UV region, and the confocal optics are assembled using a cross-slit diaphragm like an iris to eliminate stray light. This system can measure optical densities up to a maximum of 4.0. To study the effect of radiation damage, preliminary measurements of glucose isomerase and thaumatin crystals were conducted in the UV region. Spectral changes dependent on X-ray dose were observed at around 280 nm, suggesting that structural changes involving Trp or Tyr residues occurred in the protein crystal. In the case of the thaumatin crystal, a broad peak around 400 nm was also generated after X-ray irradiation, suggesting the cleavage of a disulfide bond. Dose-dependent spectral changes were also observed in cryo-solutions alone, and these changes differed with the composition of the cryo-solution. These responses in the UV region are informative regarding the state of the sample; consequently, this device might be useful for X-ray crystallography.
Roedig, Philip; Duman, Ramona; Sanchez-Weatherby, Juan; Vartiainen, Ismo; Burkhardt, Anja; Warmer, Martin; David, Christian; Wagner, Armin; Meents, Alke
2016-01-01
Recent success at X-ray free-electron lasers has led to serial crystallography experiments staging a comeback at synchrotron sources as well. With crystal lifetimes typically in the millisecond range and the latest-generation detector technologies with high framing rates up to 1 kHz, fast sample exchange has become the bottleneck for such experiments. A micro-patterned chip has been developed from single-crystalline silicon, which acts as a sample holder for up to several thousand microcrystals at a very low background level. The crystals can be easily loaded onto the chip and excess mother liquor can be efficiently removed. Dehydration of the crystals is prevented by keeping them in a stream of humidified air during data collection. Further sealing of the sample holder, for example with Kapton, is not required. Room-temperature data collection from insulin crystals loaded onto the chip proves the applicability of the chip for macromolecular crystallography. Subsequent structure refinements reveal no radiation-damage-induced structural changes for insulin crystals up to a dose of 565.6 kGy, even though the total diffraction power of the crystals has on average decreased to 19.1% of its initial value for the same dose. A decay of the diffracting power by half is observed for a dose of D 1/2 = 147.5 ± 19.1 kGy, which is about 1/300 of the dose before crystals show a similar decay at cryogenic temperatures. PMID:27275143
Measuring teamwork in primary care: Triangulation of qualitative and quantitative data.
Brown, Judith Belle; Ryan, Bridget L; Thorpe, Cathy; Markle, Emma K R; Hutchison, Brian; Glazier, Richard H
2015-09-01
This article describes the triangulation of qualitative dimensions, reflecting high functioning teams, with the results of standardized teamwork measures. The study used a mixed methods design using qualitative and quantitative approaches to assess teamwork in 19 Family Health Teams in Ontario, Canada. This article describes dimensions from the qualitative phase using grounded theory to explore the issues and challenges to teamwork. Two quantitative measures were used in the study, the Team Climate Inventory (TCI) and the Providing Effective Resources and Knowledge (PERK) scale. For the triangulation analysis, the mean scores of these measures were compared with the qualitatively derived ratings for the dimensions. The final sample for the qualitative component was 107 participants. The qualitative analysis identified 9 dimensions related to high team functioning such as common philosophy, scope of practice, conflict resolution, change management, leadership, and team evolution. From these dimensions, teams were categorized numerically as high, moderate, or low functioning. Three hundred seventeen team members completed the survey measures. Mean site scores for the TCI and PERK were 3.87 and 3.88, respectively (of 5). The TCI was associated will all dimensions except for team location, space allocation, and executive director leadership. The PERK was associated with all dimensions except team location. Data triangulation provided qualitative and quantitative evidence of what constitutes teamwork. Leadership was pivotal in forging a common philosophy and encouraging team collaboration. Teams used conflict resolution strategies and adapted to the changes they encountered. These dimensions advanced the team's evolution toward a high functioning team. (c) 2015 APA, all rights reserved).
Calculation of mean central dose in interstitial brachytherapy using Delaunay triangulation.
Astrahan, M A; Streeter, O E; Jozsef, G
2001-06-01
In 1997 the ICRU published Report 58 "Dose and Volume Specification for Reporting Interstitial Therapy" with the objective of addressing the problem of absorbed dose specification for reporting contemporary interstitial therapy. One of the concepts proposed in that report is "mean central dose." The fundamental goal of the mean central dose (MCD) calculation is to obtain a single, readily reportable and intercomparable value which is representative of dose in regions of the implant "where the dose gradient approximates a plateau." Delaunay triangulation (DT) is a method used in computational geometry to partition the space enclosed by the convex hull of a set of distinct points P into a set of nonoverlapping cells. In the three-dimensional case, each point of P becomes a vertex of a tetrahedron and the result of the DT is a set of tetrahedra. All treatment planning for interstitial brachytherapy inherently requires that the location of the radioactive sources, or dwell positions in the case of HDR, be known or digitized. These source locations may be regarded as a set of points representing the implanted volume. Delaunay triangulation of the source locations creates a set of tetrahedra without manual intervention. The geometric centers of these tetrahedra define a new set of points which lie "in between" the radioactive sources and which are distributed uniformly over the volume of the implant. The arithmetic mean of the dose at these centers is a three dimensional analog of the two-dimensional triangulation and inspection methods proposed for calculating MCD in ICRU 58. We demonstrate that DT can be successfully incorporated into a computerized treatment planning system and used to calculate the MCD.
Stochastic triangulation for prostate positioning during radiotherapy using short CBCT arcs.
Hoegele, Wolfgang; Loeschel, Rainer; Dobler, Barbara; Koelbl, Oliver; Beard, Clair; Zygmanski, Piotr
2013-02-01
Fast and reliable tumor localization is an important part of today's radiotherapy utilizing new delivery techniques. This proof-of-principle study demonstrates the use of a method called herein 'stochastic triangulation' for this purpose. Stochastic triangulation uses very short imaging arcs and a few projections. A stochastic Maximum A Posteriori (MAP) estimator is proposed based on an uncertainty-driven model of the acquisition geometry and inter-/intra-fractional deformable anatomy. The application of this method was designed to use the available linac-mounted cone-beam computed tomography (CBCT) and/or electronic portal imaging devices (EPID) for the patient setup based on short imaging arcs. For the proof-of-principle clinical demonstration, the MAP estimator was applied to 5 CBCT scans of a prostate cancer patient with 2 implanted gold markers. Estimation was performed for several (18) very short imaging arcs of 5° with 10 projections resulting in 90 estimations. Short-arc stochastic triangulation led to residual radial errors compared to manual inspection with a mean value of 1.4mm and a standard deviation of 0.9 mm (median 1.2mm, maximum 3.8mm) averaged over imaging directions all around the patient. Furthermore, abrupt intra-fractional motion of up to 10mm resulted in radial errors with a mean value of 1.8mm and a standard deviation of 1.1mm (median 1.5mm, maximum 5.6mm). Slow periodic intra-fractional motions in the range of 12 mm resulted in radial errors with a mean value of 1.8mm and a standard deviation of 1.1mm (median 1.6mm, maximum 4.7 mm). Based on this study, the proposed stochastic method is fast, robust and can be used for inter- as well as intra-fractional target localization using current CBCT units. Copyright © 2013 Elsevier Ireland Ltd. All rights reserved.
1:500 Scale Aerial Triangulation Test with Unmanned Airship in Hubei Province
Feifei, Xie; Zongjian, Lin; Dezhu, Gui
2014-03-01
A new UAVS (Unmanned Aerial Vehicle System) for low altitude aerial photogrammetry is introduced for fine surveying and mapping, including the platform airship, sensor system four-combined wide-angle camera and photogrammetry software MAP-AT. It is demonstrated that this low-altitude aerial photogrammetric system meets the precision requirements of 1:500 scale aerial triangulation based on the test of this system in Hubei province, including the working condition of the airship, the quality of image data and the data processing report. This work provides a possibility for fine surveying and mapping.
Institute of Scientific and Technical Information of China (English)
无
2002-01-01
This paper focuses on the methods and process of spatial aggregation based on semantic and geometric characteristics of spatial objects and relations among the objects with the help of spatial data structure (Formal Data Structure),the Local Constrained Delaunay Triangulations and semantic hierarchy.The adjacent relation among connected objects and unconnected objects has been studied through constrained triangle as elementary processing unit in aggregation operation.The hierarchical semantic analytical matrix is given for analyzing the similarity between objects types and between objects.Several different cases of aggregation have been presented in this paper.
Eckstein, Johannes; Lei, Wang; Becker, Jonathan; Jun, Gao; Ott, Peter
2006-04-01
In this paper a distance measurement sensor is introduced, equipped with two integrated optical systems, the first one for rotationally symmetric triangulation and the second one for imaging the object while using only one 2D detector for both purposes. Rotationally symmetric triangulation, introduced in [1], eliminates some disadvantages of classical triangulation sensors, especially at steps or strong curvatures of the object, wherefore the measurement result depends not any longer on the angular orientation of the sensor. This is achieved by imaging the scattered light from an illuminated object point to a centered and sharp ring on a low cost area detector. The diameter of the ring is proportional to the distance of the object. The optical system consists of two off axis aspheric reflecting surfaces. This system allows for integrating a second optical system in order to capture images of the object at the same 2D detector. A mock-up was realized for the first time which consists of the reflecting optics for triangulation manufactured by diamond turning. A commercially available appropriate small lens system for imaging was mechanically integrated in the reflecting optics. Alternatively, some designs of retrofocus lens system for larger field of views were investigated. The optical designs allow overlying the image of the object and the ring for distance measurement in the same plane. In this plane a CCD detector is mounted, centered to the optical axis for both channels. A fast algorithm for the evaluation of the ring is implemented. The characteristics, i.e. the ring diameter versus object distance shows very linear behavior. For illumination of the object point for distance measurement, the beam of a red laser diode system is reflected by a wavelength bandpath filter on the axis of the optical system in. Additionally, the surface of the object is illuminated by LED's in the green spectrum. The LED's are located on the outside rim of the reflecting optics. The
Triangulation in Youth Sport: Healthy Partnerships among Parents, Coaches, and Practitioners.
Blom, Lindsey C; Visek, Amanda J; Harris, Brandonn S
2013-01-01
Youth sport is unique because it involves communication, coordination, and maintenance of relationships among multiple adults, all of whom are vested stakeholders in a child-athlete's sport experience. This dynamic becomes even more complex when a sport psychology practitioner is added; therefore, the purpose of this paper is to provide guidelines and considerations to assist sport psychology practitioners in managing the triangulation of adults who are involved in the consultation process with youth athletes. We first discuss specific dyads and considerations for the practitioner and then highlight recommendations for practitioners regarding transparency and confidentiality issues specific to youth athletes.
Triangulation of multistation camera data to locate a curved line in space
Fricke, C. L.
1974-01-01
A method is described for finding the location of a curved line in space from local azimuth as a function of elevation data obtained at several observation sites. A least-squares criterion is used to insure the best fit to the data. The method is applicable to the triangulation of an object having no identifiable structural features, provided its width is very small compared with its length so as to approximate a line in space. The method was implemented with a digital computer program and was successfully applied to data obtained from photographs of a barium ion cloud which traced out the earth's magnetic field line at very high altitudes.
Triangulations, Subdivisions, and Covers for Control of Affine Hypersurface Systems on Polytopes
Lin, Zhiyun
2009-01-01
This paper studies the problem for an affine hypersurface system to reach a polytopic target set starting from inside a polytope in the state space. We present an exhaustive solution which begins with a characterization of states which can reach the target by open-loop control and concludes with a systematic procedure to synthesize a feedback control. Our emphasis is on methods of subdivision, triangulation, and covers which explicitly account for the capabilities of the control system. In contrast with previous literature, the partition methods are guaranteed to yield a correct feedback synthesis, assuming the problem is solvable by open-loop control.
Satellite triangulation in Europe from WEST and ISAGEX data. [computer programs
Leick, A.; Arur, M.
1975-01-01
Observational data that was acquired during the West European Satellite Triangulation (WEST) program and the International Satellite Geodesy Experiment (ISAGEX) campaign was obtained for the purpose of performing a geometric solution to improve the present values of coordinates of the European stations in the OSU WN14 solutions, adding some new stations and assessing the quality of the WN14 solution with the help of the additional data available. The status of the data as received, the preprocessing required and the preliminary tests carried out for the initial screening of the data are described. The adjustment computations carried out and the results of the adjustments are discussed.
Quantum gravity on a laptop: 1 + 1 Dimensional Causal Dynamical Triangulation simulation
Israel, Norman S.; Lindner, John F.
2012-01-01
The quest for quantum gravity has been long and difficult. Causal Dynamical Triangulation is a new and straightforward approach to quantum gravity that recovers classical spacetime at large scales by enforcing causality at small scales. CDT combines quantum physics with general relativity in a Feynman sum-over-geometries and converts the sum into a discrete statistical physics problem. We solve this problem using a new Monte Carlo simulation to compute the spatial fluctuations of an empty universe with one space and one time dimensions. Our results compare favorably with theory and provide an accessible but detailed introduction to quantum gravity via a simulation that runs on a laptop computer.
Lutzke, Peter; Schaffer, Martin; Kühmstedt, Peter; Kowarschik, Richard; Notni, Gunther
2013-04-01
Active triangulation systems are widely used for precise and fast measurements. Many different coding strategies have been invented to solve the correspondence problem. The quality of the measurement results depends on the accuracy of the pixel assignments. The most established method uses phase shifted-patterns projected on the scene. This is compared to a method using statistical patterns. In both coding strategies, the number and the spatial frequency of the projected patterns is varied. The measurements and calculations for all presented results were done with exactly the same measurement setup in a narrow time window to avoid any changes and to guarantee identical technical preconditions as well as comparability.
Cubic Spline Interpolation on a Class of Triangulations%一类三角域上的三次样条插值
Institute of Scientific and Technical Information of China (English)
陈丽娟; 罗钟铉
2008-01-01
In this paper, we consider spaces of cubic C1-spline on a class of trian-gulations. By using the inductive algorithm, the posed Lagrange interpolation sets are constructed for cubic spline space. It is shown that the class of triangulations considered in this paper are nonsingular for S13 spaces. Moreover, the dimensions of those spaces exactly equal to L. L. Schumaker's low bounds of the dimensions. At the end of this paper, we present an approach to construct triangulations from any scattered planar points, which ensures that the obtained triangulations for S13 space are nonsingular.
Höing, Andrea; Quinten, Marcel C; Indrawati, Yohana Maria; Cheyne, Susan M; Waltert, Matthias
2013-02-01
Estimating population densities of key species is crucial for many conservation programs. Density estimates provide baseline data and enable monitoring of population size. Several different survey methods are available, and the choice of method depends on the species and study aims. Few studies have compared the accuracy and efficiency of different survey methods for large mammals, particularly for primates. Here we compare estimates of density and abundance of Kloss' gibbons (Hylobates klossii) using two of the most common survey methods: line transect distance sampling and triangulation. Line transect surveys (survey effort: 155.5 km) produced a total of 101 auditory and visual encounters and a density estimate of 5.5 gibbon clusters (groups or subgroups of primate social units)/km(2). Triangulation conducted from 12 listening posts during the same period revealed a similar density estimate of 5.0 clusters/km(2). Coefficients of variation of cluster density estimates were slightly higher from triangulation (0.24) than from line transects (0.17), resulting in a lack of precision in detecting changes in cluster densities of triangulation and triangulation method also may be appropriate.
Interplay between the bacterial nucleoid protein H-NS and macromolecular crowding in compacting DNA
Wintraecken, C.H.J.M.
2012-01-01
In this dissertation we discuss H-NS and its connection to nucleoid compaction and organization. Nucleoid formation involves a dramatic reduction in coil volume of the genomic DNA. Four factors are thought to influence coil volume: supercoiling, DNA charge neutralization, macromolecular crow
A kinetic type extended model for dense gases and macromolecular fluids
Directory of Open Access Journals (Sweden)
M. Cristina Carrisi
2005-05-01
Full Text Available Extended thermodynamics is an important theory which is appreciated from mathematicians and physicists. Following its ideas and considering the macroscopic approach with suggestions from the kinetic one, we find in this paper, the solution of an interesting model: the model for dense gases and macromolecular fluids.
Reliable and efficient solution of genome-scale models of Metabolism and macromolecular Expression
DEFF Research Database (Denmark)
Ma, Ding; Yang, Laurence; Fleming, Ronan M. T.
2017-01-01
Constraint-Based Reconstruction and Analysis (COBRA) is currently the only methodology that permits integrated modeling of Metabolism and macromolecular Expression (ME) at genome-scale. Linear optimization computes steady-state flux solutions to ME models, but flux values are spread over many...
Gelin, F.
1996-01-01
The recognition of novel, insoluble and non-hydrolysable macromolecular constituents in protective tissues of fresh-water algae and higher plants has had a major impact on our understanding of the origin and fate of sedimentary organic matter (OM) in terrestrial and lacustrine deposits. The investig
All teaching staffs at Department of Macromolecular Science and Engineering (19 members)
2012-01-01
Recent researches, publications and achievements are presented, which were made during these five years (2007-2011) by 19 members at Department of Macromolecular Science and Engineering. Listed publications include original papers, books, reviews and reports. Achievements such as invited lectures, patents, funds and financial supports, and awards are also listed.
Synergy of DNA-bending nucleoid proteins and macromolecular crowd-condensing DNA
Bessa Ramos, E.; Wintraecken, C.H.J.M.; Geerling, A.C.M.; Vries, de R.J.
2007-01-01
Many prokaryotic nucleoid proteins bend DNA and form extended helical protein-DNA fibers rather than condensed structures. On the other hand, it is known that such proteins (such as bacterial HU) strongly promote DNA condensation by macromolecular crowding. Using theoretical arguments, we show that
The Postgraduate Study of Macromolecular Sciences at the University of Zagreb (1971-1980
Directory of Open Access Journals (Sweden)
Kunst, B.
2008-07-01
Full Text Available The postgraduate study of macromolecular sciences (PSMS was established at the University of Zagreb in 1971 as a university study in the time of expressed interdisciplinary permeation of natural sciences - physics, chemistry and biology, and application of their achievements in technologicaldisciplines. PSMS was established by a group of prominent university professors from the schools of Science, Chemical Technology, Pharmacy and Medicine, as well as from the Institute of Biology. The study comprised basic fields of macromolecular sciences: organic chemistry of synthetic macromolecules, physical chemistry of macromolecules, physics of macromolecules, biological macromolecules and polymer engineering with polymer application and processing, and teaching was performed in 29 lecture courses lead by 30 professors with their collaborators. PSMS ceased to exist with the change of legislation in Croatia in 1980, when the attitude prevailed to render back postgraduate studies to the university schools. During 9 years of existence of PSMS the MSci grade was awarded to 37 macromolecular experts. It was assessed that the PSMS some thirty years ago was an important example of modern postgraduate education as compared with the international postgraduate development. In concordance with the recent introduction of similar interdisciplinary studies in macromolecular sciences elsewhere in the world, the establishment of a modern interdisciplinary study in the field would be of importance for further development of these sciences in Croatia.
Macromolecular Crowding Modulates Folding Mechanism of α/β Protein Apoflavodoxin
Homouz, D.; Stagg, L.; Wittungstafshede, P.; Cheung, M.
2009-01-01
Protein dynamics in cells may be different from that in dilute solutions in vitro since the environment in cells is highly concentrated with other macromolecules. This volume exclusion due to macromolecular crowding is predicted to affect both equilibrium and kinetic processes involving protein conformational changes. To quantify macromolecular crowding effects on protein folding mechanisms, here we have investigated the folding energy landscape of an alpha/beta protein, apoflavodoxin, in the presence of inert macromolecular crowding agents using in silico and in vitro approaches. By coarse-grained molecular simulations and topology-based potential interactions, we probed the effects of increased volume fraction of crowding agents (phi_c) as well as of crowding agent geometry (sphere or spherocylinder) at high phi_c. Parallel kinetic folding experiments with purified Desulfovibro desulfuricans apoflavodoxin in vitro were performed in the presence of Ficoll (sphere) and Dextran (spherocylinder) synthetic crowding agents. In conclusion, we have identified in silico crowding conditions that best enhance protein stability and discovered that upon manipulation of the crowding conditions, folding routes experiencing topological frustrations can be either enhanced or relieved. The test-tube experiments confirmed that apoflavodoxin's time-resolved folding path is modulated by crowding agent geometry. We propose that macromolecular crowding effects may be a tool for manipulation of protein folding and function in living cells.
Hydropyrolysis: A new technique for the analysis of macromolecular material in meteorites
Sephton, Mark A.; Love, Gordon D.; Meredith, Will; Snape, Colin E.; Sun, Cheng-Gong; Watson, Jonathan S.
2005-10-01
The carbonaceous chondrite meteorites are fragments of asteroids that have remained relatively unprocessed since the formation of the Solar System 4.56 billion years ago. The major organic component in these meteorites is a macromolecular phase that is resistant to solvent extraction. The information contained within macromolecular material can be accessed by degradative techniques such as pyrolysis. Hydropyrolysis refers to pyrolysis assisted by high hydrogen gas pressures and a dispersed sulphided molybdenum catalyst. Hydropyrolysis of the Murchison macromolecular material successfully releases much greater quantities of hydrocarbons than traditional pyrolysis techniques (twofold greater than hydrous pyrolysis) including significant amounts of high molecular weight polyaromatic hydrocarbons (PAH) such as phenanthrene, carbazole, fluoranthene, pyrene, chrysene, perylene, benzoperylene and coronene units with varying degrees of alkylation. When hydropyrolysis products are collected using a silica trap immersed in liquid nitrogen, the technique enables the solubilisation and retention of compounds with a wide range of volatilities (i.e. benzene to coronene). This report describes the hydropyrolysis method and the information it can provide about meteorite macromolecular material constitution.
DIVE in the cosmic web: voids with Delaunay triangulation from discrete matter tracer distributions
Zhao, Cheng; Tao, Charling; Liang, Yu; Kitaura, Francisco-Shu; Chuang, Chia-Hsun
2016-07-01
We present a novel parameter-free cosmological void finder (DIVE, Delaunay TrIangulation Void findEr) based on Delaunay Triangulation (DT), which efficiently computes the empty spheres constrained by a discrete set of tracers. We define the spheres as DT voids, and describe their properties, including a universal density profile together with an intrinsic scatter. We apply this technique on 100 halo catalogues with volumes of 2.5 h-1Gpc side each, with a bias and number density similar to the Baryon Oscillation Spectroscopic Survey CMASS luminous red galaxies, performed with the PATCHY code. Our results show that there are two main species of DT voids, which can be characterized by the radius: they have different responses to halo redshift space distortions, to number density of tracers, and reside in different dark matter environments. Based on dynamical arguments using the tidal field tensor, we demonstrate that large DT voids are hosted in expanding regions, whereas the haloes used to construct them reside in collapsing ones. Our approach is therefore able to efficiently determine the troughs of the density field from galaxy surveys, and can be used to study their clustering. We further study the power spectra of DT voids, and find that the bias of the two populations are different, demonstrating that the small DT voids are essentially tracers of groups of haloes.
DIVE in the cosmic web: voids with Delaunay Triangulation from discrete matter tracer distributions
Zhao, Cheng; Liang, Yu; Kitaura, Francisco-Shu; Chuang, Chia-Hsun
2015-01-01
We present a novel parameter-free cosmological void finder (\\textsc{dive}, Delaunay TrIangulation Void findEr) based on Delaunay Triangulation (DT), which efficiently computes the empty spheres constrained by a discrete set of tracers. We define the spheres as DT voids, and describe their properties, including an universal density profile together with an intrinsic scatter. We apply this technique on 100 halo catalogues with volumes of 2.5\\,$h^{-1}$Gpc side each, with a bias and number density similar to the BOSS CMASS Luminous Red Galaxies, performed with the \\textsc{patchy} code. Our results show that there are two main species of DT voids, which can be characterised by the radius: they have different responses to halo redshift space distortions, to number density of tracers, and reside in different dark matter environments. Based on dynamical arguments using the tidal field tensor, we demonstrate that large DT voids are hosted in expanding regions, whereas the haloes used to construct them reside in collap...
Representations sociales et triangulation: une application en psychologie sociale de la sante
Directory of Open Access Journals (Sweden)
Thémis Apostolidis
Full Text Available La relation du contexte social et de la santé représente un enjeu de recherche important pour les développements actuels en psychologie sociale de la santé. L'approche des représentations sociales offre un cadre d'analyse de la pensée sociale profane concernant la maladie, en rupture avec la tradition cognitiviste et individualiste dominante dans les analyses psychosociales des risques sanitaires. Sur le plan théorico-méthodologique, cette approche permet une étude contextualisée des processus sociocognitifs qui interviennent dans la construction des risques, en opérationnalisant la double nature, produit/processus, de la représentation. Dans cette perspective, la triangulation en tant que stratégie de recherche inductive constitue une démarche privilégiée. Nous présentons une application de cette stratégie à travers une recherche sur les représentations des relations sexuelles et des risques liés au sida chez de jeunes adultes en France et en Grèce. Nous discutons la pertinence de la triangulation pour les approches "multi-niveaux" de la construction des risquesl.
Enhancing non-melonic triangulations: A tensor model mixing melonic and planar maps
Bonzom, Valentin; Rivasseau, Vincent
2015-01-01
Ordinary tensor models of rank $D\\geq 3$ are dominated at large $N$ by tree-like graphs, known as melonic triangulations. We here show that non-melonic contributions can be enhanced consistently, leading to different types of large $N$ limits. We first study the most generic quartic model at $D=4$, with maximally enhanced non-melonic interactions. The existence of the $1/N$ expansion is proved and we further characterize the dominant triangulations. This combinatorial analysis is then used to define a non-quartic, non-melonic class of models for which the large $N$ free energy and the relevant expectations can be calculated explicitly. They are matched with random matrix models which contain multi-trace invariants in their potentials: they possess a branched polymer phase and a 2D quantum gravity phase, and a transition between them whose entropy exponent is positive. Finally, a non-perturbative analysis of the generic quartic model is performed, which proves analyticity in the coupling constants in cardioid ...
Enhancing non-melonic triangulations: A tensor model mixing melonic and planar maps
Directory of Open Access Journals (Sweden)
Valentin Bonzom
2015-06-01
Full Text Available Ordinary tensor models of rank D≥3 are dominated at large N by tree-like graphs, known as melonic triangulations. We here show that non-melonic contributions can be enhanced consistently, leading to different types of large N limits. We first study the most generic quartic model at D=4, with maximally enhanced non-melonic interactions. The existence of the 1/N expansion is proved and we further characterize the dominant triangulations. This combinatorial analysis is then used to define a non-quartic, non-melonic class of models for which the large N free energy and the relevant expectations can be calculated explicitly. They are matched with random matrix models which contain multi-trace invariants in their potentials: they possess a branched polymer phase and a 2D quantum gravity phase, and a transition between them whose entropy exponent is positive. Finally, a non-perturbative analysis of the generic quartic model is performed, which proves analyticity in the coupling constants in cardioid domains.
Curvature Matrix Models for Dynamical Triangulations and the Itzykson-Di Francesco Formula
Szabó, R J; Szabo, Richard J.; Wheater, John F.
1996-01-01
We study the large-$N$ limit of a class of matrix models for dually weighted triangulated random surfaces using character expansion techniques. We show that for various choices of the weights of vertices of the dynamical triangulation the model can be solved by resumming the Itzykson-Di Francesco formula over congruence classes of Young tableau weights modulo three. From this we show that the large-$N$ limit implies a non-trivial correspondence with models of random surfaces weighted with only even coordination number vertices. We examine the critical behaviour and evaluation of observables and discuss their interrelationships in all models. We obtain explicit solutions of the model for simple choices of vertex weightings and use them to show how the matrix model reproduces features of the random surface sum. We show that a class of matrix models admits complex saddle-point solutions of the Itzykson-Di Francesco formula, and we present the general technique of dealing with such solutions. We find that the set...
Fast and automatic identification of particle tilt pairs based on Delaunay triangulation.
Vilas, J L; Navas, J; Gómez-Blanco, J; de la Rosa-Trevín, J M; Melero, R; Peschiera, I; Ferlenghi, I; Cuenca, J; Marabini, R; Carazo, J M; Vargas, J; Sorzano, C O S
2016-12-01
Random conical tilt (RCT) and orthogonal tilt reconstruction (OTR) are two remarkable methods for reconstructing the three-dimensional structure of macromolecules at low resolution. These techniques use two images at two different sample tilts. One of the most demanding steps in these methods at the image processing level is to identify corresponding particles on both micrographs, and manual or semiautomatic matching methods are usually used. Here we present an approach to solve this bottleneck with a fully automatic method for assigning particle tilt pairs. This new algorithm behaves correctly with a variety of samples, covering the range from small to large macromolecules and from sparse to densely populated fields of view. It is also more rapid than previous approaches. The roots of the method lie in a Delaunay triangulation of the set of independently picked coordinates on both the untilted and tilted micrographs. These triangulations are then used to search an affine transformation between the untilted and tilted triangles. The affine transformation that maximizes the number of correspondences between the two micrographs defines the coordinate matching. Copyright © 2016 Elsevier Inc. All rights reserved.
Yang, Hongwei; Tao, Wei; Zhang, Zhengqi; Zhao, Siwei; Yin, Xiaoqia; Zhao, Hui
2017-05-15
Directional dithering of a laser beam potentially limits the detection accuracy of a laser triangulation displacement probe. A theoretical analysis indicates that the measurement accuracy will linearly decrease as the laser dithering angle increases. To suppress laser dithering, a scheme for reduction of the influence of laser beam directional dithering in a laser triangulation displacement probe, which consists of a collimated red laser, a laser beam pointing control setup, a receiver lens, and a charge-coupled device, is proposed in this paper. The laser beam pointing control setup is inserted into the source laser beam and the measured object and can separate the source laser beam into two symmetrical laser beams. Hence, at the angle at which the source laser beam dithers, the positional averages of the two laser spots are equal and opposite. Moreover, a virtual linear function method is used to maintain a stable average of the positions of the two spots on the imaging side. Experimental results indicate that with laser beam pointing control, the estimated standard deviation of the fitting error decreases from 0.3531 mm to 0.0100 mm , the repeatability accuracy can be lowered from ±7 mm to ±5 μ m , and the nonlinear error can be reduced from ±6 % FS (full scale) to ±0.16 % FS.
Indirect measurement of molten steel level in tundish based on laser triangulation
Energy Technology Data Exchange (ETDEWEB)
Su, Zhiqi; He, Qing, E-mail: heqing@ise.neu.edu.cn; Xie, Zhi [State Key Laboratory of Synthetical Automation for Process Industries, School of Information Science and Engineering, Northeastern University, Shenyang 110819 (China)
2016-03-15
For real-time and precise measurement of molten steel level in tundish during continuous casting, slag level and slag thickness are needed. Among which, the problem of slag thickness measurement has been solved in our previous work. In this paper, a systematic solution for slag level measurement based on laser triangulation is proposed. Being different from traditional laser triangulation, several aspects for measuring precision and robustness have been done. First, laser line is adopted for multi-position measurement to overcome the deficiency of single point laser range finder caused by the uneven surface of the slag. Second, the key parameters, such as installing angle and minimum requirement of the laser power, are analyzed and determined based on the gray-body radiation theory to fulfill the rigorous requirement of measurement accuracy. Third, two kinds of severe noises in the acquired images, which are, respectively, caused by heat radiation and Electro-Magnetic Interference (EMI), are cleaned via morphological characteristic of the liquid slag and color difference between EMI and the laser signals, respectively. Fourth, as false target created by stationary slag usually disorders the measurement, valid signals of the slag are distinguished from the false ones to calculate the slag level. Then, molten steel level is obtained by the slag level minus the slag thickness. The measuring error of this solution is verified by the applications in steel plants, which is ±2.5 mm during steady casting and ±3.2 mm at the end of casting.
Arain, Nabeel A; Cadeddu, Jeffrey A; Hogg, Deborah C; Bergs, Richard; Fernandez, Raul; Scott, Daniel J
2012-09-01
This study evaluated operative outcomes and workload during single-site laparoscopy (SSL) using a magnetically anchored cautery dissector (MAGS) compared with a conventional laparoscopic hook cautery (LAP). Each cautery was used to perform six SSL porcine cholecystectomies. For MAGS, the cautery device was inserted through the umbilical incision, magnetically coupled, and deployed; two graspers and a laparoscope were used. For LAP, two percutaneous retraction sutures, one grasper, a hook cautery dissector, and a laparoscope were used. Operative outcomes, surgeon ratings (scale, 1-5; 1 = superior), and workload (scale, 1-10; 1 = superior) were evaluated. No significant differences were detected for operative outcomes and surgeon ratings, however, trends were detected favoring MAGS. Surgeon workload ratings were significantly better for MAGS (2.6 ± 0.2) vs. LAP (5.6 ± 1.1; p triangulation were excellent and the safe handling protocol was followed with no complications. For LAP, the parallelism of instruments and lack of triangulation hindered depth perception, caused instrument conflicts, and resulted in two minor complications (one superficial liver laceration and one inadvertent burn to the diaphragm). These data suggest that using the MAGS device for SSL cholecystectomy results in equivalent (or better) operative outcomes and less workload compared with LAP.
Research on spot of CCD subdivided locating methods in laser triangulation displacement measurement
Wang, Hongjun; Hui, Lei; Zhang, Jiaying
2017-02-01
In order to improve the measurement accuracy of the laser displacement sensor, the laser triangulation displacement measuring system is established. The spot subdivision location algorithms of the system are studied, such as the Gaussian curve fitting, traditional gray weighted centroid and gray square weighted centroid. First, according to the principle of laser triangulation, the displacement measuring system is built. Then, objects are moved by the high-precision motorized stage, obtaining multiple sets of image data. Next, these data respectively are processed by the above several algorithms to obtain the corresponding coordinates of the laser spot, the system is calibrated respectively. Finally, comparing the displacement of calibration results calculating with the actual displacement. The results show that: those data that are processed by the gray square weighted centroid are used to calibrate , calculating the minimum error, and is 71.1 μm. It concludes that gray square weighted centroid is an ideal location segmentation method, which is not only simple and easy to implement, but also has a higher positioning accuracy.
The worst visibility walk in a random Delaunay triangulation is $O(\\sqrt{n}$
Directory of Open Access Journals (Sweden)
Olivier Devillers
2016-07-01
Full Text Available We show that the memoryless routing algorithms Greedy Walk, Compass Walk, and all variants of visibility walk based on orientation predicates are asymptotically optimal in the average case on the Delaunay triangulation. More specifically, we consider the Delaunay triangulation of an unbounded Poisson point process of unit rate and demonstrate that, for any pair of vertices $(s,t$ inside $[0,n]^2$, the ratio between the longest and shortest visibility walks between $s$ and $t$ is bounded by a constant with probability converging to one (as long as the vertices are sufficiently far apart. As a corollary, it follows that the worst-case path has $O(\\sqrt{n}\\,$ steps in the limiting case, under the same conditions. Our results have applications in routing in mobile networks and also settle a long-standing conjecture in point location using walking algorithms. Our proofs use techniques from percolation theory and stochastic geometry.
A Data Forwarding Scheme Based on Delaunay Triangulation for Cyber-Physical Systems
Directory of Open Access Journals (Sweden)
Junhai Luo
2013-01-01
Full Text Available Cyber-physical system (CPS cooperates with physical processes, computing, communication, and control (3C into multiple levels of information processing and operation management to streamline and fortify the operation of physical systems. Due to the unique characteristics, such as unpredictable node mobility, low node density, lack of global information and network intermittent connectivity, an algorithm for data forwarding in CPS is a considerably difficult and challenging problem, and there is no good solution to it in existing works. In this paper, we propose a fully-fledged data forwarding algorithm tailored to the CPS environment. The proposed protocol, called data forwarding based on Delaunay triangulation (DFDT, takes into account the computational geometry based on Delaunay triangulation to form a few triangle communities according to nodes’ connectivity. Data in a community are forwarded to other nodes once a node comes into this community to increase the data delivery ratio. DFDT achieves a good performance by data gathering and sending data to other nodes with higher probability of meeting the link. An extensive simulation has been performed to validate the analytical results and to show the effectiveness of our approach compared with the three existing popular data forwarding algorithms.
Indirect measurement of molten steel level in tundish based on laser triangulation.
Su, Zhiqi; He, Qing; Xie, Zhi
2016-03-01
For real-time and precise measurement of molten steel level in tundish during continuous casting, slag level and slag thickness are needed. Among which, the problem of slag thickness measurement has been solved in our previous work. In this paper, a systematic solution for slag level measurement based on laser triangulation is proposed. Being different from traditional laser triangulation, several aspects for measuring precision and robustness have been done. First, laser line is adopted for multi-position measurement to overcome the deficiency of single point laser range finder caused by the uneven surface of the slag. Second, the key parameters, such as installing angle and minimum requirement of the laser power, are analyzed and determined based on the gray-body radiation theory to fulfill the rigorous requirement of measurement accuracy. Third, two kinds of severe noises in the acquired images, which are, respectively, caused by heat radiation and Electro-Magnetic Interference (EMI), are cleaned via morphological characteristic of the liquid slag and color difference between EMI and the laser signals, respectively. Fourth, as false target created by stationary slag usually disorders the measurement, valid signals of the slag are distinguished from the false ones to calculate the slag level. Then, molten steel level is obtained by the slag level minus the slag thickness. The measuring error of this solution is verified by the applications in steel plants, which is ±2.5 mm during steady casting and ±3.2 mm at the end of casting.
Long, S. A. T.
1973-01-01
The triangulation method developed specifically for the Barium Ion Cloud Project is discussed. Expression for the four displacement errors, the three slope errors, and the curvature error in the triangulation solution due to a probable error in the lines-of-sight from the observation stations to points on the cloud are derived. The triangulation method is then used to determine the effect of the following on these different errors in the solution: the number and location of the stations, the observation duration, east-west cloud drift, the number of input data points, and the addition of extra cameras to one of the stations. The pointing displacement errors, and the pointing slope errors are compared. The displacement errors in the solution due to a probable error in the position of a moving station plus the weighting factors for the data from the moving station are also determined.
Ponappa, Sujata; Bartle-Haring, Suzanne; Holowacz, Eugene; Ferriby, Megan
2017-01-01
Guided by Bowen theory, we investigated the relationships between parent-child triangulation, parental differential treatment (PDT), sibling warmth, and individual depressive symptoms in a sample of 77 sibling dyads, aged 18-25 years, recruited through undergraduate classes at a U.S. public University. Results of the actor-partner interdependence models suggested that being triangulated into parental conflict was positively related to both siblings' perception of PDT; however, as one sibling felt triangulated, the other perceived reduced levels of PDT. For both siblings, the perception of higher levels of PDT was related to decreased sibling warmth and higher sibling warmth was associated with fewer depressive symptoms. The implications of these findings for research and the treatment of depression in the college-aged population are discussed. © 2016 American Association for Marriage and Family Therapy.
Turkowski, Kari L; Tester, David J; Bos, J Martijn; Haugaa, Kristina H; Ackerman, Michael J
2017-03-01
Arrhythmogenic cardiomyopathy (ACM) is a heritable disease characterized by fibrofatty replacement of cardiomyocytes, has a prevalence of approximately 1 in 5000 individuals, and accounts for approximately 20% of sudden cardiac death in the young (≤35 years). ACM is most often inherited as an autosomal dominant trait with incomplete penetrance and variable expression. While mutations in several genes that encode key desmosomal proteins underlie about half of all ACM, the remainder is elusive genetically. Here, whole exome sequencing (WES) was performed with genomic triangulation in an effort to identify a novel explanation for a phenotype-positive, genotype-negative multi-generational pedigree with a presumed autosomal dominant, maternal inheritance of ACM. WES and genomic triangulation was performed on a symptomatic 14-year-old female proband, her affected mother and affected sister, and her unaffected father to elucidate a novel ACM-susceptibility gene for this pedigree. Following variant filtering using Ingenuity® Variant Analysis, gene priority ranking was performed on the candidate genes using ToppGene and Endeavour. The phylogenetic and physiochemical properties of candidate mutations were assessed further by 6 in silico prediction tools. Species alignment and amino acid conservation analysis was performed using the Uniprot Consortium. Tissue expression data was abstracted from Expression Atlas. Following WES and genomic triangulation, CDH2 emerged as a novel, autosomal dominant, ACM-susceptibility gene. The CDH2-encoded N-cadherin is a cell-cell adhesion protein predominately expressed in the heart. Cardiac dysfunction has been demonstrated in prior CDH2 knockout and over-expression animal studies. Further in silico mutation prediction, species conservation, and protein expression analysis supported the ultra-rare (minor allele frequency <0.005%) p.Asp407Asn-CDH2 variant as a likely pathogenic variant. Herein, it is demonstrated that genetic mutations in
Triangle geometry processing for surface modeling and cartesian grid generation
Aftosmis, Michael J [San Mateo, CA; Melton, John E [Hollister, CA; Berger, Marsha J [New York, NY
2002-09-03
Cartesian mesh generation is accomplished for component based geometries, by intersecting components subject to mesh generation to extract wetted surfaces with a geometry engine using adaptive precision arithmetic in a system which automatically breaks ties with respect to geometric degeneracies. During volume mesh generation, intersected surface triangulations are received to enable mesh generation with cell division of an initially coarse grid. The hexagonal cells are resolved, preserving the ability to directionally divide cells which are locally well aligned.
Curtis, Joseph E.; Raghunandan, Sindhu; Nanda, Hirsh; Krueger, Susan
2012-02-01
A program to construct ensembles of biomolecular structures that are consistent with experimental scattering data are described. Specifically, we generate an ensemble of biomolecular structures by varying sets of backbone dihedral angles that are then filtered using experimentally determined restraints to rapidly determine structures that have scattering profiles that are consistent with scattering data. We discuss an application of these tools to predict a set of structures for the HIV-1 Gag protein, an intrinsically disordered protein, that are consistent with small-angle neutron scattering experimental data. We have assembled these algorithms into a program called SASSIE for structure generation, visualization, and analysis of intrinsically disordered proteins and other macromolecular ensembles using neutron and X-ray scattering restraints. Program summaryProgram title: SASSIE Catalogue identifier: AEKL_v1_0 Program summary URL:http://cpc.cs.qub.ac.uk/summaries/AEKL_v1_0.html Program obtainable from: CPC Program Library, Queen's University, Belfast, N. Ireland Licensing provisions: GNU General Public License v3 No. of lines in distributed program, including test data, etc.: 3 991 624 No. of bytes in distributed program, including test data, etc.: 826 Distribution format: tar.gz Programming language: Python, C/C++, Fortran Computer: PC/Mac Operating system: 32- and 64-bit Linux (Ubuntu 10.04, Centos 5.6) and Mac OS X (10.6.6) RAM: 1 GB Classification: 3 External routines: Python 2.6.5, numpy 1.4.0, swig 1.3.40, scipy 0.8.0, Gnuplot-py-1.8, Tcl 8.5, Tk 8.5, Mac installation requires aquaterm 1.0 (or X window system) and Xcode 3 development tools. Nature of problem: Open source software to generate structures of disordered biological molecules that subsequently allow for the comparison of computational and experimental results is limiting the use of scattering resources. Solution method: Starting with an all atom model of a protein, for example, users can input
Bergasa-Caceres, Fernando; Rabitz, Herschel A.
2014-01-01
A model of protein folding kinetics is applied to study the combined effects of protein flexibility and macromolecular crowding on protein folding rate and stability. It is found that the increase in stability and folding rate promoted by macromolecular crowding is damped for proteins with highly flexible native structures. The model is applied to the folding dynamics of the murine prion protein (121-231). It is found that the high flexibility of the native isoform of the murine prion protein (121-231) reduces the effects of macromolecular crowding on its folding dynamics. The relevance of these findings for the pathogenic mechanism are discussed.
Rodríguez-Ruiz, Isaac; Radajewski, Dimitri; Charton, Sophie; Phamvan, Nhat; Brennich, Martha; Pernot, Petra; Bonneté, Françoise; Teychené, Sébastien
2017-06-02
The relevance of coupling droplet-based Photonic Lab-on-a-Chip (PhLoC) platforms and Small-Angle X-Ray Scattering (SAXS) technique is here highlighted for the performance of high throughput investigations, related to the study of protein macromolecular interactions. With this configuration, minute amounts of sample are required to obtain reliable statistical data. The PhLoC platforms presented in this work are designed to allow and control an effective mixing of precise amounts of proteins, crystallization reagents and buffer in nanoliter volumes, and the subsequent generation of nanodroplets by means of a two-phase flow. Spectrophotometric sensing permits a fine control on droplet generation frequency and stability as well as on concentration conditions, and finally the droplet flow is synchronized to perform synchrotron radiation SAXS measurements in individual droplets (each one acting as an isolated microreactor) to probe protein interactions. With this configuration, droplet physic-chemical conditions can be reproducibly and finely tuned, and monitored without cross-contamination, allowing for the screening of a substantial number of saturation conditions with a small amount of biological material. The setup was tested and validated using lysozyme as a model of study. By means of SAXS experiments, the proteins gyration radius and structure envelope were calculated as a function of protein concentration. The obtained values were found to be in good agreement with previously reported data, but with a dramatic reduction of sample volume requirements compared to studies reported in the literature.
A stereo triangulation system for structural identification: Analytical and experimental results
Junkins, J. L.; James, G. H., III; Pollock, T. C.; Rahman, Z. H.
1988-01-01
Identification of large space structures' distributed mass, stiffness, and energy dissipation characteristics poses formidable analytical, numerical, and implementation difficulties. Development of reliable on-orbit structural identification methods is important for implementing active vibration suppression concepts which are under widespread study in the large space structures community. Near the heart of the identification problem lies the necessity of making a large number of spatially distributed measurements of the structure's vibratory response and the associated force/moment inputs with sufficient spatial and frequency resolution. In the present paper, we discuss a method whereby tens of active or passive (retro-reflecting) targets on the structure are tracked simultaneously by the focal planes of two or more video cameras mounted on an adjacent platform. Triangulation (optical ray intersection) of the conjugate image centroids yield inertial trajectories of each target on the structure. Given the triangulated motion of the targets, we apply and extend methodology developed by Creamer, Junkins, and Juang to identify the frequencies, mode shapes, and updated estimates for the mass/stiffness/damping parameterization of the structure. The methodology is semi-automated, for example, the post experiment analysis of the video imagery to determine the inertial trajectories of the targets typically requires less than thirty minutes of real time. Using methodology discussed herein, the frequency response of a large number of points on the structure (where reflective targets are mounted) on the structure can be determined from optical measurements alone. For comparison purposes, we also utilize measurements from accelerometers and a calibrated impulse hammer. While our experimental work remains in a research stage of development, we have successfully tracked and stereo triangulated 20 targets (on a vibrating cantilevered grid structure) at a sample frequency of 200 HZ
Heraud, J. A.; Centa, V. A.; Bleier, T.
2015-12-01
During several sessions in past AGU meetings, reports on the progress of analysis of magnetometer data have been given, as our research moved from a one dimensional geometry, to two and finally to a three dimensional image. In the first case, we learned how to extract one coordinate, azimuth information, on the occurrence of an earthquake based on the processing of mono-polar pulses received at a single station. A two dimensional geometry was implemented through triangulation and we showed the use of this technique to find out where a future epicenter would occur. Recently, we have obtained compelling evidence that the pressure points leading to the determination of future epicenters originate at a plane, inclined with the same angle as the subduction zone, a three-dimensional position of the future hypocenter. Hence, an image of the subduction zone or interface between the Nazca plate and the continental plate in the northern area of Lima, Peru, has been obtained, corresponding to the subduction zone obtained by traditional seismic methods. Our work with magnetometers deployed along part of the Peruvian coast since 2009, has shown that it is possible to measure, with significant precision, the azimuth of electromagnetic pulses propagating from stress points in the earth's crust due to the subduction of tectonic plates, as to be able to determine precisely the origin of the pulses. The occurrence of earthquakes approximately 11 to 18 days after the appearance of the first pulses and the recognition of grouping of such pulses, has allowed us to determine accurately the direction and the timing of future seismic events. Magnetometers, donated by Quakefinder and Telefonica del Peru were then strategically installed in different locations in Peru with the purpose of achieving triangulation. During two years since 2013, about a dozen earthquakes have been associated with future seismic activity in a pre or post occurrence way. Our presentation will be based on animated
Optimal tetrahedral mesh generation for three-dimensional point set
Institute of Scientific and Technical Information of China (English)
秦开怀; 吴边; 关右江; 葛振州
1997-01-01
Three-dimensional (3D) tnangulation is a basic topic in computer graphics. It is considered very difficult to obtain the global optimal 3D triangulatlon, such as the triangulation which satisfies the max-min solid angle criterion A new method called genetic tetrahedral mesh generation algorithm (GTMGA for short) is presented. GT-MGA is based on the principle of genetic algorithm and aims at the global optimal triangulation. With a multi-objective fitness function, GTMGA is able to perform optimizations for different requirements. New crossover operator and mutation operator, polyhedron crossover and polyhedron mutation, are used in GTMGA. It is shown by the experimental results that GTMGA works better than both the 3D Delaunay triangulation and the algorithm based on local transformations.