bluuebunny/crossref_metadata_2025_split huggingface dataset:
Phospholipase D Activation Correlates with Microtubule Reorganization in Living Plant Cells[W]
Authors: Dhonukshe Pankaj , Laxalt Ana M. , Goedhart Joachim , Gadella Theodorus W. J. , Munnik Teun 
Published: November 2003

AbstractA phospholipase D (PLD) was shown recently to decorate microtubules in plant cells. Therefore, we used tobacco BY-2 cells expressing the microtubule reporter GFP-MAP4 to test whether PLD activation affects the organization of plant microtubules. Within 30 min of adding n-butanol, a potent activator of PLD, cortical microtubules were released from the plasma membrane and partially depolymerized, as visualized with four-dimensional confocal imaging. The isomers sec- and tert-butanol, which did not activate PLD, did not affect microtubule organization. The effect of treatment on PLD activation was monitored by the in vivo formation of phosphatidylbutanol, a specific reporter of PLD activity. Tobacco cells also were treated with mastoparan, xylanase, NaCl, and hypoosmotic stress as reported activators of PLD. We confirmed the reports and found that all treatments induced microtubule reorganization and PLD activation within the same time frame. PLD still was activated in microtubule-stabilized (taxol) and microtubule-depolymerized (oryzalin) situations, suggesting that PLD activation triggers microtubular reorganization and not vice versa. Exogenously applied water-soluble synthetic phosphatidic acid did not affect the microtubular cytoskeleton. Cell cycle studies revealed that n-butanol influenced not just interphase cortical microtubules but also those in the preprophase band and phragmoplast, but not those in the spindle structure. Cell growth and division were inhibited in the presence of n-butanol, whereas sec- and tert-butanol had no such effects. Using these novel insights, we propose a model for the mechanism by which PLD activation triggers microtubule reorganization in plant cells.
Differential Subnuclear Localization of RNA Strands of Opposite Polarity Derived from an Autonomously Replicating Viroid[W]
Authors: Qi Yijun , Ding Biao 
Published: November 2003

AbstractThe wide variety of RNAs produced in the nucleus must be localized correctly to perform their functions. However, the mechanism of this localization is poorly understood. We report here the differential subnuclear localization of RNA strands of opposite polarity derived from the replicating Potato spindle tuber viroid (PSTVd). During replication, (+)- and (−)-strand viroid RNAs are produced. We found that in infected cultured cells and plants, the (−)-strand RNA was localized in the nucleoplasm, whereas the (+)-strand RNA was localized in the nucleolus as well as in the nucleoplasm with distinct spatial patterns. Furthermore, the presence of the (+)-PSTVd in the nucleolus caused the redistribution of a small nucleolar RNA. Our results support a model in which (1) the synthesis of the (−)- and (+)-strands of PSTVd RNAs occurs in the nucleoplasm, (2) the (−)-strand RNA is anchored in the nucleoplasm, and (3) the (+)-strand RNA is transported selectively into the nucleolus. Our results imply that the eukaryotic cell has a machinery that recognizes and localizes the opposite strands of an RNA, which may have broad ramifications in the RNA regulation of gene expression and the infection cycle of pathogenic RNAs and in the development of RNA-based methods to control gene expression as well as pathogen infection.
Institutions of Conflict Management and Economic Growth in the European Union
Authors: Schneider Friedrich , Wagner Alexander F. 
Published: November 2003

High‐quality institutions of conflict management can serve to mitigate the negative effects of adverse external shocks and social conflict on long‐run economic growth. But in addition to the benefits (production‐enhancing cooperation), there are also costs (taxes and rent‐seeking) of conflict‐management institutions like corporatism and trust. We examine both positive and negative influences in the context of a simple growth model. Contrary to previous research, we predict a non‐linear relationship between institutions and growth. The empirical evidence from a panel for the years 1961‐1995 shows that neo‐corporatism and trust have each had independent positive effects on long‐run growth in the EU, suggesting that the diminishing product range of institutions has not yet been reached. Under an increasing size of government, however, both institutions lead to a dominating negative rent‐seeking effect.Our thanks for helpful comments go to the editors, an anonymous referee, Karl Aiginger, Mathias Dufour, Frauke Skudelny, Robert Urbatsch, seminar participants at the University of Linz, the Austrian Institute for Economic Research and discussants at the European Public Choice Society Meeting 2000 in Siena. All remaining errors are ours, of course. An extended version of this paper is available from the authors on request (Schneider and Wagner 2001). Further results are discussed in Wagner (2000).
European Monetary Union, the Term Structure, and the Lucas Critique
Authors: Bergeijk Peter A. G. Van , Berk Jan Marc 
Published: November 2003

In order to evaluate the empirical relevance of the Lucas Critique, we investigate whether the term structure (the relation of the long interest rate to the short interest rate) showed structural change as the deadline for the euro came closer. Our empirical analysis of the term structures (yield curves) in 12 OECD countries uncovers that econometrically estimated behavioural equations for most EMU countries were stable even in the light of the creation of the euro. This finding would seem to defy the Lucas Critique. However, the significant structural instability found for the euro area's core country, Germany, suggests that the Lucas Critique is relevant in the analysis of the impact of the creation (and future extensions) of EMU.Preliminary versions of this paper were presented at the ECB workshop on yield curve modelling, Frankfurt (1999) and the Finance Seminar at the University of Zurich (2000). Comments by participants of both workshops and by two anonymous referees are gratefully acknowledged.
Volumetric Filtering, Modeling and Visualization for Nano‐Medicine
Authors: Bajaj Chandrajit 
Published: November 2003

Abstract The 3D structures of individual proteins or small complexes, such as most of the Protein Data Bank entries, are still unable to yield the ''full picture'' of a functional biological complex. The study of large macromolecular complexes, such as viruses, ion channels, the ribosome and other macromolecular machines of various types, offer more complete structural and functional description of the nano‐machinery of life. In addition to x‐ray crystallography. NMR spectroscopy, electron cryomicroscopy (cryoEM) imaging of single particles, and in‐vivo molecular tomographic imaging has become indispensable at revealing the structures of large macromolecular complexes at subnanometer resolutions. In this talk, I shall describe some of the recent computational advances in filtering, modeling, analysis and visualization, that have propelled structure determination by cryoEM and tomographic imaging, to steadily increasing accuracy.
Freeform Shape Representations for Efficient Geometry Processing
Authors: Kobbelt Leif 
Published: November 2003

Abstract The most important concepts for the handling and storage of freeform shapes in geometry processing applications are parametric representations and volumetric representations. Both have their specific advantages and drawbacks. While the algebraic complexity of volumetric representations is independent from the shape complexity, the domain of a parametric representation usually has to have the same structure as the surface itself (which sometimes makes it necessary to update the domain when the surface is modified). On the other hand, the topology of a parametrically defined surface can be controlled explicitly while in a volumetric representation, the surface topology can change accidentally during deformation. A volumetric representation reduces distance queries or inside/outside tests to mere function evaluations but the geodesic neighborhood relation between surface points is difficult to resolve. As a consequence, it seems promising to combine parametric and volumetric representations to effectively exploit both advantages. In this talk, a number of projects are presented and discussed in which such a combination leads to efficient and numerically stable algorithms for the solution of various geometry processing tasks. Applications include global error control for mesh decimation and smoothing, topology control for level‐set surfaces, and shape modeling with unstructured point clouds.
On Visual Similarity Based 3D Model Retrieval
Authors: Chen Ding‐Yun , Tian Xiao‐Pei , Shen Yu‐Te , Ouhyoung Ming 
Published: November 2003

AbstractA large number of 3D models are created and available on the Web, since more and more 3D modelling anddigitizing tools are developed for ever increasing applications. The techniques for content‐based 3D model retrievalthen become necessary. In this paper, a visual similarity‐based 3D model retrieval system is proposed.This approach measures the similarity among 3D models by visual similarity, and the main idea is that if two 3Dmodels are similar, they also look similar from all viewing angles. Therefore, one hundred orthogonal projectionsof an object, excluding symmetry, are encoded both by Zernike moments and Fourier descriptors as features forlater retrieval. The visual similarity‐based approach is robust against similarity transformation, noise, model degeneracyetc., and provides 42%, 94% and 25% better performance (precision‐recall evaluation diagram) thanthree other competing approaches: (1) the spherical harmonics approach developed by Funkhouser et al., (2) theMPEG‐7 Shape 3D descriptors, and (3) the MPEG‐7 Multiple View Descriptor. The proposed system is on the Webfor practical trial use (http://3d.csie.ntu.edu.tw), and the database contains more than 10,000 publicly available3D models collected from WWW pages. Furthermore, a user friendly interface is provided to retrieve 3D modelsby drawing 2D shapes. The retrieval is fast enough on a server with Pentium IV 2.4 GHz CPU, and it takes about2 seconds and 0.1 seconds for querying directly by a 3D model and by hand drawn 2D shapes, respectively.Categories and Subject Descriptors (according to ACM CCS): H.3.1 [Information Storage and Retrieval]: Indexing Methods
Field Functions for Blending Range Controls on Soft Objects
Authors: Hsu P. C. , Lee C. 
Published: November 2003

Abstract This paper proposes new field functions that have adjustable inner radius and outer radius of influence. Incorporatingthe proposed field functions with soft object modeling, soft blending, Ricci's super‐ellipsoid blends, Perlin'sset operations, and R‐functions, etc. can have blending range controls by adjusting the inner and the outer radiiof influence of given field functions. As a result, the sizes of the resulting blending surfaces on soft objects willnot be restricted by the sizes of the blended primitive soft objects and can be enlarged and shrunk freely withoutdeforming the overall shapes of blended primitive soft objects. In addition, a small soft object can have a largeblending region, and a large one can have a small blending region Categories and Subject Descriptors (according to ACM CCS): I.3.5 [Computer Graphics]: Computational Geometry and Object Modeling ‐ Curve, surface, solid and object representations
Fast Photo‐Realistic Rendering of Trees in Daylight
Authors: Qin Xueying , Nakamae Eihachiro , Tadamura Katsumi , Nagai Yasuo 
Published: November 2003

Abstract We propose a fast approach for photo‐realistic rendering of trees under various kinds of daylight, which is particularlyuseful for the environmental assessment of landscapes. In our approach the 3D tree models are transformedto a quasi‐3D tree database registering geometrical and shading information of tree surfaces, i.e. their normalvectors, relative depth, and shadowing of direct sunlight and skylight, by using a combination of 2D buffers.Thus the rendering speed of quasi‐3D trees depends on their display sizes only, regardless of the complexity oftheir original 3D tree models. By utilizing a two‐step shadowing algorithm, our proposed method can create highquality forest scenes illuminated by both sunlight and skylight at a low cost. It can generate both umbrae andpenumbrae on a tree cast by other trees and any other objects such as buildings or clouds. Transparency, specularreflection and inter‐reflection of leaves, which influence the delicate shading effects of trees, can also be simulatedwith verisimilitude. Categories and Subject Descriptors (according to ACM CCS): I.3.7 [Computer Graphics]: Three dimensional Graphics and Realism
Multi‐scale Feature Extraction on Point‐Sampled Surfaces
Authors: Pauly Mark , Keiser Richard , Gross Markus 
Published: November 2003

Abstract We present a new technique for extracting line‐type features on point‐sampled geometry. Given an unstructuredpoint cloud as input, our method first applies principal component analysis on local neighborhoods toclassify points according to the likelihood that they belong to a feature. Using hysteresis thresholding, we thencompute a minimum spanning graph as an initial approximation of the feature lines. To smooth out the featureswhile maintaining a close connection to the underlying surface, we use an adaptation of active contour models.Central to our method is a multi‐scale classification operator that allows feature analysis at multiplescales, using the size of the local neighborhoods as a discrete scale parameter. This significantly improves thereliability of the detection phase and makes our method more robust in the presence of noise. To illustrate theusefulness of our method, we have implemented a non‐photorealistic point renderer to visualize point‐sampledsurfaces as line drawings of their extracted feature curves.
ShieldTester: Cell‐to‐Cell Visibility Test for Surface Occluders
Authors: Navazo I. , Rossignac J. , Jou J. , Shariff R. 
Published: November 2003

Abstract We present a novel Cell‐To‐Cell Visibility (C2CV) algorithm, which given two polyhedra, AandBand a connectedand oriented manifold triangle mesh, S offers a simple, fast and conservative test for detecting when A and B areoccluded from each other by S. Previously disclosed C2CV algorithms either relied on costly occlusion fusion orwere restricted to convex or “apparently convex” occluders, which makes them inappropriate for scenes wherepotential occluders are arbitrary triangulated surfaces, such as the body of a car or a portion of a terrain. Thesimplicity of our C2CV algorithm, named ShieldTester, stems from a new Occlusion Theorem, introduced herewhich permits to establish occlusion by computing the intersection of S with a single ray from a vertex ofAtoa vertex ofB. ShieldTester may be used to establish that pairs of cells in a subdivision of space are hidden fromeach other by a relatively large surface occluder, so that when the viewer is in one cell, the objects in the othercell need not be displayed.Categories and Subject Descriptors (according to ACM CCS): I.3.3 [Computer Graphics]: Computational Geometryand Object Modeling: Occlussion Culling, Visibility Test, Triangle Meshes
Volumetric cell‐and‐portal generation
Authors: Haumont D. , Debeir O. , Sillion F. 
Published: November 2003

Abstract We present an algorithm to generate a cell‐and‐portal decomposition of general indoor scenes. The method is an adaptation of the 3D watershed transform, computed on a distance‐to‐geometry sampled field. The watershed is processed using a flooding analogy in the distance field space. Flooding originates from local minima, each minimum producing a region. Portals are built as needed to avoid the merging of regions during their growth. As a result, the cell‐and‐portal decomposition is closely linked to the structure of the models. In a building, the algorithm finds all the rooms, doors and windows. To restrict the memory load, a hierarchical implementation of the algorithm is presented. We also explain how to handle possible model degeneracies ‐such as cracks, holes and interpenetrating geometries‐ using a pre‐voxelisation step. The hierarchical algorithm, preceded when necessary by the pre‐voxelisation, was tested on a large range of models. We show that it is able to deal with classical architectural models, as well as cave‐like environments and large mixed indoor/outdoor scenes. Thanks to the intermediate distance field representation, the algorithm can be used regardless of the way the model is represented: it deals with parametric curves, implicit surfaces, volumetric data and polygon soups in a unified way.
Planning Collision‐Free Reaching Motions for Interactive Object Manipulation and Grasping
Authors: Kallmann Marcelo , Aubel Amaury , Abaci Tolga , Thalmann Daniel 
Published: November 2003

Abstract We present new techniques that use motion planning algorithms based on probabilistic roadmaps to control 22 degrees of freedom (DOFs) of human‐like characters in interactive applications. Our main purpose is the automatic synthesis of collision‐free reaching motions for both arms, with automatic column control and leg flexion. Generated motions are collision‐free, in equilibrium, and respect articulation range limits. In order to deal with the high (22) dimension of our configuration space, we bias the random distribution of configurations to favor postures most useful for reaching and grasping. In addition, extensions are presented in order to interactively generate object manipulation sequences: a probabilistic inverse kinematics solver for proposing goal postures matching pre‐designed grasps; dynamic update of roadmaps when obstacles change position; online planning of object location transfer; and an automatic stepping control to enlarge the character's reachable space. This is, to our knowledge, the first time probabilistic planning techniques are used to automatically generate collision‐free reaching motions involving the entire body of a human‐like character at interactive frame rates. Categories and Subject Descriptors (according to ACM CCS): I.3.7 [Computer Graphics]: Three‐Dimensional Graphics and Realism
Hierarchical and Heterogenous Reactive Agents for Real‐Time Applications
Authors: Niederberger C. , Gross M. 
Published: November 2003

AbstractWe present a generic concept for autonomous agents with reactive behavior based on situation recognition in real‐time environments. Our approach facilitates behavior development through specialization of existing behavior types or weighted multiple inheritance in order to create new types. Additionally, the system allows for the simultaneous generation of hierarchical and semi‐individual group organizations using specification and recursive or modulo‐based patterns. Our framework is designed to support the creation of large numbers of secondary characters with individual and group behavior in simulation environments such as game engines. The engine allows for the specification of a maximal time‐per‐run in order to guarantee a minimal and constant frame‐rate. We demonstrate the usefulness of our approach by various examples with up to hundreds of individuals.Categories and Subject Descriptors (according to ACM CCS): 1.2.11 [Distributed Artificial Intelligence]: Multiagent systems, I.6.7 [Simulation Support Systems]: Environments
Hierarchical Context‐based Pixel Ordering
Authors: Bar‐Joseph Ziv , Cohen‐Or Daniel 
Published: November 2003

Abstract We present a context‐based scanning algorithm which reorders the input image using a hierarchical representationof the image. Our algorithm optimally orders (permutes) the leaves corresponding to the pixels, by minimizing thesum of distances between neighboring pixels. The reordering results in an improved autocorrelation betweennearby pixels which leads to a smoother image. This allows us, for the first time, to improve image compressionrates using context‐based scans. The results presented in this paper greatly improve upon previous work in bothcompression rate and running time. Categories and Subject Descriptors (according to ACM CCS): I.3.5 [Computer Graphics]: Computational Geometryand Object Modeling I.3.6 [Computer Graphics]: Methodology and Techniques
Rendering and Affect
Authors: Duke D.J. , Barnard P.J. , Halper N. , Mellin M. 
Published: November 2003

Abstract Previous studies at the intersection between rendering and psychology have concentrated on issues such as realismand acuity. Although such results have been useful in informing development of realistic rendering techniques,studies have shown that the interpretation of images is influenced by factors that have little to do with realism. Inthis paper, we summarize a series of experiments, the most recent of which are reported in a separate paper, thatinvestigate affective (emotive) qualities of images. These demonstrate significant effects that can be utilized withininteractive graphics, particularly via non‐photorealistic rendering (NPR). We explain how the interpretation ofthese results requires a high‐level model of cognitive information processing, and use such a model to account forrecent empirical results on rendering and judgement. Categories and Subject Descriptors (according to ACM CCS): I.3.m [Computer Graphics]: Miscellaneous
A Few Good Lines: Suggestive Drawing of 3D Models
Authors: Sousa Mario Costa , Prusinkiewicz Przemyslaw 
Published: November 2003

Abstract We present a method for rendering 3D models in the traditionalline‐drawing style used in artistic and scientificillustrations. The goal is to suggest the 3D shape of the objectsusing a small number of lines drawn with carefullychosen line qualities. The system combines several known techniquesinto a simple yet effective non‐photorealisticline renderer. Feature edges related to the outline and interiorof a given 3D mesh are extracted, segmented, andsmoothed, yielding chains of lines with varying path, length, thickness,gaps, and enclosures. The paper includessample renderings obtained for a variety of models.
Realistic Animation of Fluid with Splash and Foam
Authors: Takahashi Tsunemi , Fujii Hiroko , Kunimatsu Atsushi , Hiwada Kazuhiro , Saito Takahiro , Tanaka Ken , Ueki Heihachi 
Published: November 2003

AbstractIn this paper we describe a method for modeling and rendering dynamic behavior of fluids withsplashes and foam. A particle system is built into a fluid simulation system to represent an ocean wavecresting and spraying over another object. We use the Cubic Interpolated Propagation (CIP) method asthe fluid solver. The CIP method can solve liquid and gas together in the framework of fluid dynamicsand has high accuracy in the case of relatively coarse grids. This enables us to simulate the fluids in ashort time and describe the motion of splashes in the air that is associated with the liquid motion well.The foam floating on the water also can be described using the particle system. We integrate the rigidbody simulation with the fluid and particle system to create sophisticated scenes including splashes andfoam. We construct state change rules that are used with the particle system. This controls the generation,vanishing and transition rule of splashes and foam. The transition rule makes the seamless connection betweena splash and foam. We employed a fast volume rendering method with scattering effect for particles.One of the important features of our method is the combination of fast simulation and rendering techniques,which provides dynamic and realistic scenes in a short time.