bluuebunny/crossref_metadata_2025 huggingface dataset:
Improved Antibiotic-Impregnated Catheters with Extended-Spectrum Activity against Resistant Bacteria and Fungi
Authors: Raad Issam , Mohamed Jamal A. , Reitzel Ruth A. , Jiang Ying , Raad Sammy , Al Shuaibi Munirah , Chaftari Anne-Marie , Hachem Ray Y.
Published: November 2011

Minocycline-rifampin-impregnated central venous catheters (M/R CVCs) have been shown to be efficacious in reducing catheter-related bloodstream infections (CRBSI) and inhibiting the biofilm adherence of resistant Gram-positive and Gram-negative pathogens, with the exception of
Pseudomonas aeruginosa
and
Candida
spp. To expand the spectrum of antimicrobial activity, a novel second-generation M/R catheter was developed by adding chlorhexidine (CHX-M/R). CVCs and peripherally inserted central catheters (PICCs) were impregnated with CHX-M/R and compared with first-generation M/R catheters, CHX-silver sulfadiazine-treated CVCs (CHX/SS-CVCs), chlorhexidine-treated PICCs, and uncoated catheters. A biofilm catheter colonization model was used to assess the efficacy of catheters against methicillin-resistant
Staphylococcus aureus
(MRSA), vancomycin-resistant
Enterococcus faecium
(VRE),
P. aeruginosa
,
Candida albicans
, and
Candida glabrata
. CHX-M/R-impregnated CVCs were the only antimicrobial catheters that completely inhibited the biofilm colonization of all resistant bacterial and fungal organisms tested at all time intervals, and they were significantly superior to uncoated catheters (all
P
values were ≤0.003). Furthermore, CHX-M/R-coated CVCs had a significantly more effective and prolonged (up to 3 weeks) antimicrobial activity against MRSA and
P. aeruginosa
than M/R, CHX/SS, and uncoated CVCs (
P
< 0.0001). Similarly, CHX-M/R-coated PICCs were also superior to M/R-coated and CHX-coated PICCs in preventing biofilms of MRSA, VRE,
P. aeruginosa
, and
Candida
species (
P
value = 0.003 for all). Our study shows that novel CHX-M/R-coated catheters have unique properties in completely inhibiting biofilm colonization of MRSA, VRE,
P. aeruginosa
, and fungi in a manner superior to that of M/R- and chlorhexidine-treated catheters.
The Campbellton Formation, New Brunswick, Canada: paleoenvironments in an important Early Devonian terrestrial locality
Authors: Kennedy Kirsten , Gibling Martin R.
Published: November 2011

Strata of the Campbellton Formation, nearly 1 km-thick and known for its diverse fossil assemblage of early plants, arthropods, and fish, can be divided into six facies associations: (1) restricted lacustrine, (2) marginal lacustrine, (3) near-shore lacustrine, (4) coastal-deltaic, (5) sandy to gravelly alluvial plain, and (6) gravelly proximal alluvial environments. Lacustrine deposits with restricted circulation, due to depth or stagnation, are fine-grained with preserved organic material. The marginal lacustrine association consists of massive siltstone and very fine sandstone, interbedded with conglomerate. The latter are interpreted to have shed from older volcanic units forming the basin walls. The near-shore lacustrine association is characterized by rippled sandstone with microbialites. Alluvial strata include interbedded imbricate to nonimbricate conglomerate, trough cross-stratified sandstone, and barren to plant-bearing siltstone. Rare exposures of thickly bedded imbricate to weakly imbricated cobble–boulder conglomerate with sandy plant-bearing lenses are interpreted as products of hyperconcentrated debris flows. In the western belt, a braided-fluvial system had paleocurrents flowing WNW. Coastal-deltaic deposits west of the fluvial outcrops, containing aquatic vertebrates and invertebrates, had paleocurrents flowing ESE, suggesting a confined body of fresh or brackish water. In lower parts of the eastern belt, lacustrine facies are prevalent, representing a large open lake. Alluvial facies dominate upper parts of the formation, representing an eastward-flowing axial braided river system, with proximal alluvium shed transversely from the basin margins. Although most strata have a volcanic provenance, only one outcrop in the lacustrine beds shows evidence of active volcanism during deposition of the Campbellton Formation.
Ecological controls on Devonian stromatoporoid-dominated and coral-dominated reef growth in the Mackenzie Basin, Northwest Territories, Canada
Authors: Corlett Hilary , Jones Brian
Published: November 2011

The Horn Plateau Formation, composed of isolated reefs, is part of the Devonian strata that formed in the Mackenzie Basin in the Northwest Territories, Canada. The reefs stretch over a ∼350 m northeast–southwest trend and are dominated by tabulate and rugose corals in the northeast, near exposed Canadian Shield rocks, and stromatoporoids further out in the basin. Detailed facies analyses of each reef type shows distinct differences in their biological makeup, energy regimes, and carbonate sedimentation rates. Geochemical analyses (stable isotopes and rare-earth elements) set against established paleogeography in the Mackenzie Basin reveal that the coral-dominated and stromatoporoid-dominated reefs grew under different ecological conditions. Separations in the data imply that the coral-dominated reefs grew in waters that were relatively enriched in nutrients and the stromatoporoid-dominated reefs, further down the ramp, were in oligotrophic conditions. With no current established method to directly measure Paleozoic nutrient levels or to detect where they were sourced from, it is unclear why the coral-dominated reefs experienced higher nutrient levels. The paleogeography of the Mackenzie Basin could have affected the apparent stratification of nutrients on the carbonate ramp. Possible nutrient sources in the area are from coastal upwelling from the open ocean northwest of the ramp, or locally sourced nutrients from runoff on the adjacent exposed Canadian Shield rocks.
The chronostratigraphy of Holocene sediments from four Lake Superior sub-basins1Laboratory for Stable Isotope Science (LSIS) Contribution 264.
Authors: Hyodo Ayumi , Longstaffe Fred J.
Published: November 2011

Radiocarbon dates, rhythmite occurrences, mineralogy, grain size, and stable isotopic compositions of detrital calcite obtained for four sediment cores from Lake Superior have been used to produce a chronology for these fine-grained deposits over the last ∼10 500 cal BP (calibrated years before A.D. 1950). Most of the rhythmites have been interpreted as annual laminations (varves) based on systematic variations in the carbonate content of rhythmite couplets and correlation of the rhythmite packages with varve sequences reported previously for Lake Superior sediments. Glacial sediments in these cores, which consist of red and grey clay, range in age from ∼10 500 to 8800–8700 cal BP. Distinctive carbon and oxygen isotopic compositions of allochthonous calcite in the red versus grey glacial clays point to different sources for this detritus. Final termination of glacial meltwater input into the Lake Superior Basin occurred between 9000 and 8700 cal BP. The significant decrease in sediment carbonate content over this time is a convenient marker for the start of postglacial sedimentation across the Lake Superior Basin.
CHAOS ROBUSTNESS AND STRENGTH IN THERMOMECHANICAL SHAPE MEMORY OSCILLATORS PART I: A PREDICTIVE THEORETICAL FRAMEWORK FOR THE PSEUDOELASTIC BEHAVIOR
Authors: BERNARDINI DAVIDE , REGA GIUSEPPE
Published: November 2011

In this two-part paper the problem of evaluating robustness and strength of chaos in thermomechanically-based Shape Memory Oscillators (SMO) is addressed. In the first part, a theoretical analysis of the main features of the pseudoelastic loops exhibited by the underlying Shape Memory Devices (SMD) is accomplished with the aim to establish a predictive framework for accompanying numerical investigations. The analysis is based on the evaluation of suitable synthetic indicators of the SMD behavior that can be computed from the model parameters before the computation of SMO actual trajectories, and provide information about the hysteresis loops and their dependence on temperature variations. By means of such indicators, a detailed analysis of the influence of thermomechanical coupling on the rate-dependent mechanical response is presented. It is shown that a careful interpretation of the synthetic indicators permits to obtain a reasonable estimation of the influence of various model parameters on the hysteresis loop area and slopes of the pseudoelastic plateaus, that are the main global aspects influencing the occurrence of chaotic responses. In the second part, the theoretical predictions based on the synthetic indicators will be exploited to interpret the results of a systematic numerical investigation based on an enhanced version of the Method of Wandering Trajectories.
A NUMERICAL STUDY OF DAM-BREAK FLOW AND SEDIMENT TRANSPORT FROM A QUAKE LAKE
Authors: LIN PENGZHI , WU YINNA , BAI JUNLI , LIN QUANHONG
Published: November 2011

Dam-break flows are simulated numerically by a two-dimensional shallow-water-equation model that combines a hydrodynamic module and a sediment transport module. The model is verified by available analytical solutions and experimental data. It is demonstrated that the model is a reliable tool for the simulation of various transient shallow water flows and the associated sediment transport and bed morphology on complex topography. The validated model is then applied to investigate the potential dam-break flows from Tangjiashan Quake Lake resulting from Wenchuan Earthquake in 2008. The dam-break flow evolution is simulated by using the model in order to provide the flooding patterns (e.g., arrival time and flood height) downstream. Furthermore, the sediment transport and bed morphology simulation is performed locally to study the bed variation under the high-speed dam-break flow.
MULTI-LEVEL, MULTI-FACTOR OPTIMIZATION IN DECISION MAKING FOR EMERGENCY TREATMENT OF QUAKE LAKES
Authors: ZHOU HONGWEI , ZHANG LIN , YANG XINGGUO , LI HONGTAO , ZHOU JIAWEN , QIAO LU , LIN YUANYUAN
Published: November 2011

One hundred and thirty three quake lakes were formed in Wenchuan Earthquake of May 12. There may be several or even a dozen quake lakes in the same drainage basin. During the emergency treatment of quake lakes, due to constraints of resources and time, it is often imperative to select one or a few quake lakes of high priority in the same drainage basin for treatment in order for the entire drainage basin to safely pass the flood season. There are many factors involved in the optimization of emergency treatment project of quake lakes and these factors are usually of different nature. This article proposes to use a multi-level, multi-factor optimization method in decision making of emergency treatment of quake lakes based on the concept and operation properties of fuzzy-consistent matrix. This method is convenient and practical when many qualitative factors are involved and the determination of membership function is difficult. A case study was conducted for the 16 quake lakes on the Mianyuan River by using the proposed method. Three quake lakes selected according to case study results went through emergency treatment before the 2009 flood season, helping the entire Mianyuan River safely pass the 2009 flood season.
The character of rock surfaces formed in Mode I
Authors: Butenuth C. , de Freitas M. H.
Published: November 2011

Samples failed in extension, i.e. in Mode I, are distinguishable from those failed in shear and mixed modes, i.e. in Modes II and III, by the macroscopic and microscopic character of their failure surface, i.e. by the fractography of their surfaces. This paper describes the use of fractography to discover whether the results of a rock test to failure have been influenced by both the properties of the rock tested and the test method used. The test in question (the hoop test) is relatively new and its operation has not yet been fully analysed; however, the use of fractography has confirmed the mode of failure operating in the test is tensile (Mode I). Further, fractography enables the results obtained from these tests on rock to be better interpreted and analysed with greater confidence than was the case before.
LARK
Authors: Dini Gianluca , Savino Ida M.
Published: November 2011

Group communication has proven a powerful paradigm for designing applications and services in Wireless Sensor Networks (WSNs). Given the tight interaction between WSNs and the physical world, a security infringement may translate into a safety infringement. Therefore, in order to fully exploit the group communication paradigm we need to secure it. Traditionally, this requirement has been formalized in terms of
backward
and
forward security
and fulfilled by means of
rekeying
. In WSNs, group rekeying becomes particularly a complex problem because communication takes place over an easily accessible wireless medium and because sensor nodes have severe limitations in terms of computing, storage, energy, and tamper-resistance capabilities for cost reasons.

In this article we present a
Lightweight Authenticated ReKeying
(LARK) scheme for clustered WSNs. LARK guarantees backward and forward security, is scalable in terms of communication overhead, and efficient in terms of computing overhead for key authentiticy verification. LARK achieves security, efficiency, and scalability by exploiting two basic well-known mechanisms, namely
key graph
and
key chain
, and integrating them in an original way. LARK supports a general group model where groups can be hierachical and partially overlapping. In contrast to other WSN group rekeying schemes, LARK considers grouping a tool for designing and implementing applications and services rather than for network management. Consequently, LARK receives a group topology reflecting the application needs and manages rekeying at single-group level. In the article we describe LARK, formally argue that it meets the backward and forward security requirements, and, finally, evaluate its performance in terms of communication, computing, and storage overhead in limited-resources sensor nodes.
Shape space exploration of constrained meshes
Authors: Yang Yong-Liang , Yang Yi-Jun , Pottmann Helmut , Mitra Niloy J.
Published: November 2011

We present a general computational framework to locally characterize any shape space of meshes implicitly prescribed by a collection of non-linear constraints. We computationally access such manifolds, typically of high dimension and co-dimension, through first and second order approximants, namely tangent spaces and quadratically parameterized osculant surfaces. Exploration and navigation of desirable subspaces of the shape space with regard to application specific quality measures are enabled using approximants that are intrinsic to the underlying manifold and directly computable in the parameter space of the osculant surface. We demonstrate our framework on shape spaces of planar quad (PQ) meshes, where each mesh face is constrained to be (nearly) planar, and circular meshes, where each face has a circumcircle. We evaluate our framework for navigation and design exploration on a variety of inputs, while keeping context specific properties such as fairness, proximity to a reference surface, etc.
Imperceptible relaxation of collision avoidance constraints in virtual crowds
Authors: Kulpa Richard , Olivierxs Anne-Hélène , Ondřej Jan , Pettré Julien
Published: November 2011

The performance of an interactive virtual crowd system for entertainment purposes can be greatly improved by setting a level-of-details (LOD) strategy: in distant areas, collision avoidance can even be stealthy disabled to drastically speed-up simulation and to handle huge crowds. The greatest difficulty is then to select LODs to progressively simplify simulation in an imperceptible but efficient manner. The main objective of this work is to experimentally evaluate spectators' ability to detect the presence of collisions in simulations. Factors related to the conditions of observation and simulation are studied, such as the camera angles, distance to camera, level of interpenetration or crowd density. Our main contribution is to provide a LOD selection function resulting from two perceptual studies allowing crowd system designers to scale a simulation by relaxing the collision avoidance constraint in a least perceptible manner. The relaxation of this constraint is an important source for computational resources savings. Our results reveal several misconceptions in previously used LOD selection functions and suggest yet unexplored variables to be considered. We demonstrate our function efficiency over several evaluation scenarios.
Simple quad domains for field aligned mesh parametrization
Authors: Tarini Marco , Puppo Enrico , Panozzo Daniele , Pietroni Nico , Cignoni Paolo
Published: November 2011

We present a method for the global parametrization of meshes that preserves alignment to a cross field in input while obtaining a parametric domain made of few coarse axis-aligned rectangular patches, which form an abstract base complex without T-junctions. The method is based on the topological simplification of the cross field in input, followed by global smoothing.
Global parametrization of range image sets
Authors: Pietroni Nico , Tarini Marco , Sorkine Olga , Zorin Denis
Published: November 2011

We present a method to globally parameterize a surface represented by height maps over a set of planes (range images). In contrast to other parametrization techniques, we do not start with a manifold mesh. The parametrization we compute defines a manifold structure, it is seamless and globally smooth, can be aligned to geometric features and shows good quality in terms of angle and area preservation, comparable to current parametrization techniques for meshes. Computing such global seamless parametrization makes it possible to perform quad remeshing, texture mapping and texture synthesis and many other types of geometry processing operations. Our approach is based on a formulation of the Poisson equation on a manifold structure defined for the surface by the range images. Construction of such global parametrization requires only a way to project surface data onto a set of planes, and can be applied directly to implicit surfaces, nonmanifold surfaces, very large meshes, and collections of range scans. We demonstrate application of our technique to all these geometry types.
Image-based bidirectional scene reprojection
Authors: Yang Lei , Tse Yu-Chiu , Sander Pedro V. , Lawrence Jason , Nehab Diego , Hoppe Hugues , Wilkins Clara L.
Published: November 2011

We introduce a method for increasing the framerate of real-time rendering applications. Whereas many existing temporal upsampling strategies only reuse information from previous frames, our bidirectional technique reconstructs intermediate frames from a pair of consecutive rendered frames. This significantly improves the accuracy and efficiency of data reuse since very few pixels are simultaneously occluded in both frames. We present two versions of this basic algorithm. The first is appropriate for fill-bound scenes as it limits the number of expensive shading calculations, but involves rasterization of scene geometry at each intermediate frame. The second version, our more significant contribution, reduces both shading and geometry computations by performing reprojection using only image-based buffers. It warps and combines the adjacent rendered frames using an efficient iterative search on their stored scene depth and flow. Bidirectional reprojection introduces a small amount of lag. We perform a user study to investigate this lag, and find that its effect is minor. We demonstrate substantial performance improvements (3--4x) for a variety of applications, including vertex-bound and fill-bound scenes, multi-pass effects, and motion blur.
A shading reuse method for efficient micropolygon ray tracing
Authors: Hou Qiming , Zhou Kun
Published: November 2011

We present a shading reuse method for micropolygon ray tracing. Unlike previous shading reuse methods that require an explicit object-to-image space mapping for shading density estimation or shading accuracy, our method performs shading density control and actual shading reuse in different spaces with uncorrelated criterions. Specifically, we generate the shading points by shooting a user-controlled number of shading rays from the image space, while the evaluated shading values are assigned to antialiasing samples through object-space nearest neighbor searches. Shading samples are generated in separate layers corresponding to first bounce ray paths to reduce spurious reuse from very different ray paths. This method eliminates the necessity of an explicit object-to-image space mapping, enabling the elegant handling of ray tracing effects such as reflection and refraction. The overhead of our shading reuse operations is minimized by a highly parallel implementation on the GPU. Compared to the state-of-the-art micropolygon ray tracing algorithm, our method is able to reduce the required shading evaluations by an order of magnitude and achieve significant performance gains.
Arcimboldo-like collage using internet images
Authors: Huang Hua , Zhang Lei , Zhang Hong-Chao
Published: November 2011

Collage is a composite artwork made from assemblage of different material forms. In this work, we present a novel approach for creating a fantastic collage artform, namely Arcimboldo-like collage, which represents an input image with multiple thematically-related cutouts from the filtered Internet images. Due to the massive data of Internet images, competent image cutouts can almost always be discovered to match the segmented components of the input image. The selected cutouts are purposefully arranged such that as a whole assembly, they can represent the input image with disguise in both shape and color; but separately, individual cutout is still recognizable as its own being. Experimental results and user study show that our algorithm can effectively produce the entertaining Arcimboldo-like collages.
Rendering synthetic objects into legacy photographs
Authors: Karsch Kevin , Hedau Varsha , Forsyth David , Hoiem Derek
Published: November 2011

We propose a method to realistically insert synthetic objects into existing photographs without requiring access to the scene or any additional scene measurements. With a single image and a small amount of annotation, our method creates a physical model of the scene that is suitable for realistically rendering synthetic objects with diffuse, specular, and even glowing materials while accounting for lighting interactions between the objects and the scene. We demonstrate in a user study that synthetic images produced by our method are confusable with real scenes, even for people who believe they are good at telling the difference. Further, our study shows that our method is competitive with other insertion methods while requiring less scene information. We also collected new illumination and reflectance datasets; renderings produced by our system compare well to ground truth. Our system has applications in the movie and gaming industry, as well as home decorating and user content creation, among others.
Artist friendly facial animation retargeting
Authors: Seol Yeongho , Seo Jaewoo , Kim Paul Hyunjin , Lewis J. P. , Noh Junyong
Published: November 2011

This paper presents a novel facial animation retargeting system that is carefully designed to support the animator's workflow. Observation and analysis of the animators' often preferred process of key-frame animation with blendshape models informed our research. Our retargeting system generates a similar set of blendshape weights to those that would have been produced by an animator. This is achieved by rearranging the group of blendshapes into several sequential retargeting groups and solving using a matching pursuit-like scheme inspired by a traditional key-framing approach. Meanwhile, animators typically spend a tremendous amount of time simplifying the dense weight graphs created by the retargeting. Our graph simplification technique effectively produces editable weight graphs while preserving the visual characteristics of the original retargeting. Finally, we automatically create GUI controllers to help artists perform key-framing and editing very efficiently. The set of proposed techniques greatly reduce the time and effort required by animators to achieve high quality retargeted facial animations.
Compression and direct manipulation of complex blendshape models
Authors: Seo Jaewoo , Irving Geoffrey , Lewis J. P. , Noh Junyong
Published: November 2011

We present a method to compress complex blendshape models and thereby enable interactive, hardware-accelerated animation of these models. Facial blendshape models in production are typically large in terms of both the resolution of the model and the number of target shapes. They are represented by a single huge blendshape matrix, whose size presents a storage burden and prevents real-time processing. To address this problem, we present a new matrix compression scheme based on a hierarchically semi-separable (HSS) representation with matrix block reordering. The compressed data are also suitable for parallel processing. An efficient GPU implementation provides very fast feedback of the resulting animation. Compared with the original data, our technique leads to a huge improvement in both storage and processing efficiency without incurring any visual artifacts. As an application, we introduce an extended version of the direct manipulation method to control a large number of facial blendshapes efficiently and intuitively.
Freeform vector graphics with controlled thin-plate splines
Authors: Finch Mark , Snyder John , Hoppe Hugues
Published: November 2011

Recent work defines vector graphics using diffusion between colored curves. We explore higher-order fairing to enable more natural interpolation and greater expressive control. Specifically, we build on thin-plate splines which provide smoothness everywhere except at user-specified tears and creases (discontinuities in value and derivative respectively). Our system lets a user sketch discontinuity curves without fixing their colors, and sprinkle color constraints at sparse interior points to obtain smooth interpolation subject to the outlines. We refine the representation with novel contour and slope curves, which anisotropically constrain interpolation derivatives. Compound curves further increase editing power by expanding a single curve into multiple offsets of various basic types (value, tear, crease, slope, and contour). The vector constraints are discretized over an image grid, and satisfied using a hierarchical solver. We demonstrate interactive authoring on a desktop CPU.
Coons BVH for freeform geometric models
Authors: Kim Yong-Joon , Oh Young-Taek , Yoon Seung-Hyun , Kim Myung-Soo , Elber Gershon
Published: November 2011

We present a compact representation for the bounding volume hierarchy (BVH) of freeform NURBS surfaces using Coons patches. Following the Coons construction, each subpatch can be bounded very efficiently using the bilinear surface determined by the four corners. The BVH of freeform surfaces is represented as a hierarchy of Coons patch approximation until the difference is reduced to within a given error bound. Each leaf node contains a single Coons patch, where a detailed BVH for the patch can be represented very compactly using two lists (containing curve approximation errors) of length proportional only to the height of the BVH. We demonstrate the effectiveness of our compact BVH representation using several experimental results from real-time applications in collision detection and minimum distance computation for freeform models.
Estimating dual-scale properties of glossy surfaces from step-edge lighting
Authors: Wang Chun-Po , Snavely Noah , Marschner Steve
Published: November 2011

This paper introduces a rapid appearance capture method suited for a variety of common indoor surfaces, in which a single photograph of the reflection of a step edge is used to estimate both a BRDF and a statistical model for visible surface geometry, or mesostructure. It is applicable to surfaces with statistically stationary variation in surface height, even when these variations are large enough to produce visible texture in the image. Results are shown from a prototype system using a separate camera and LCD, demonstrating good visual matches for a range of man-made indoor materials.
Interactive hair rendering and appearance editing under environment lighting
Authors: Xu Kun , Ma Li-Qian , Ren Bo , Wang Rui , Hu Shi-Min
Published: November 2011

We present an interactive algorithm for hair rendering and appearance editing under complex environment lighting represented as spherical radial basis functions (SRBFs). Our main contribution is to derive a compact 1D circular Gaussian representation that can accurately model the hair scattering function introduced by [Marschner et al. 2003]. The primary benefit of this representation is that it enables us to evaluate, at run-time, closed-form integrals of the scattering function with each SRBF light, resulting in efficient computation of both single and multiple scatterings. In contrast to previous work, our algorithm computes the rendering integrals entirely on the fly and does not depend on expensive pre-computation. Thus we allow the user to dynamically change the hair scattering parameters, which can vary spatially. Analyses show that our 1D circular Gaussian representation is both accurate and concise. In addition, our algorithm incorporates the eccentricity of the hair. We implement our algorithm on the GPU, achieving interactive hair rendering and simultaneous appearance editing under complex environment maps for the first time.
Image smoothing via
L
0
gradient minimization
Authors: Xu Li , Lu Cewu , Xu Yi , Jia Jiaya
Published: November 2011

We present a new image editing method, particularly effective for sharpening major edges by increasing the steepness of transition while eliminating a manageable degree of low-amplitude structures. The seemingly contradictive effect is achieved in an optimization framework making use of
L
0
gradient minimization, which can globally control how many non-zero gradients are resulted in to approximate prominent structure in a sparsity-control manner. Unlike other edge-preserving smoothing approaches, our method does not depend on local features, but instead globally locates important edges. It, as a fundamental tool, finds many applications and is particularly beneficial to edge extraction, clip-art JPEG artifact removal, and non-photorealistic effect generation.
GPU-efficient recursive filtering and summed-area tables
Authors: Nehab Diego , Maximo André , Lima Rodolfo S. , Hoppe Hugues
Published: November 2011

Image processing operations like blurring, inverse convolution, and summed-area tables are often computed efficiently as a sequence of 1D recursive filters. While much research has explored parallel recursive filtering, prior techniques do not optimize across the entire filter sequence. Typically, a separate filter (or often a causal-anticausal filter pair) is required in each dimension. Computing these filter passes independently results in significant traffic to global memory, creating a bottleneck in GPU systems. We present a new algorithmic framework for parallel evaluation. It partitions the image into 2D blocks, with a small band of additional data buffered along each block perimeter. We show that these perimeter bands are sufficient to accumulate the effects of the successive filters. A remarkable result is that the image data is read only twice and written just once, independent of image size, and thus total memory bandwidth is reduced even compared to the traditional serial algorithm. We demonstrate significant speedups in GPU computation.
Practical filtering for efficient ray-traced directional occlusion
Authors: Egan Kevin , Durand Frédo , Ramamoorthi Ravi
Published: November 2011

Ambient occlusion and directional (spherical harmonic) occlusion have become a staple of production rendering because they capture many visually important qualities of global illumination while being reusable across multiple artistic lighting iterations. However, ray-traced solutions for hemispherical occlusion require many rays per shading point (typically 256-1024) due to the full hemispherical angular domain. Moreover, each ray can be expensive in scenes with moderate to high geometric complexity. However, many nearby rays sample similar areas, and the final occlusion result is often low frequency. We give a frequency analysis of shadow light fields using distant illumination with a general BRDF and normal mapping, allowing us to share ray information even among complex receivers. We also present a new rotationally-invariant filter that easily handles samples spread over a large angular domain. Our method can deliver 4x speed up for scenes that are computationally bound by ray tracing costs.
Progressive photon beams
Authors: Jarosz Wojciech , Nowrouzezahrai Derek , Thomas Robert , Sloan Peter-Pike , Zwicker Matthias
Published: November 2011

We present progressive photon beams, a new algorithm for rendering complex lighting in participating media. Our technique is efficient, robust to complex light paths, and handles heterogeneous media and anisotropic scattering while provably converging to the correct solution using a bounded memory footprint. We achieve this by extending the recent photon beams variant of volumetric photon mapping. We show how to formulate a progressive radiance estimate using photon beams, providing the convergence guarantees and bounded memory usage of progressive photon mapping. Progressive photon beams can robustly handle situations that are difficult for most other algorithms, such as scenes containing participating media and specular interfaces, with realistic light sources completely enclosed by refractive and reflective materials. Our technique handles heterogeneous media and also trivially supports stochastic effects such as depth-of-field and glossy materials. Finally, we show how progressive photon beams can be implemented efficiently on the GPU as a splatting operation, making it applicable to interactive and real-time applications. These features make our technique scalable, providing the same physically-based algorithm for interactive feedback and reference-quality, unbiased solutions.
Structure-preserving retargeting of irregular 3D architecture
Authors: Lin Jinjie , Cohen-Or Daniel , Zhang Hao , Liang Cheng , Sharf Andrei , Deussen Oliver , Chen Baoquan
Published: November 2011

We present an algorithm for interactive
structure-preserving
retargeting of
irregular
3D architecture models, offering the modeler an easy-to-use tool to quickly generate a variety of 3D models that resemble an input piece in its structural style. Working on a more global and structural level of the input, our technique allows and even encourages replication of its structural elements, while taking into account their semantics and expected geometric interrelations such as alignments and adjacency. The algorithm performs automatic replication and scaling of these elements while preserving their structures. Instead of formulating and solving a complex constrained optimization, we decompose the input model into a set of sequences, each of which is a 1D structure that is relatively straightforward to retarget. As the sequences are retargeted in turn, they progressively constrain the retargeting of the remaining sequences. We demonstrate interactivity and variability of results from our retargeting algorithm using many examples modeled after real-world architectures exhibiting various forms of irregularity.
Conjoining Gestalt rules for abstraction of architectural drawings
Authors: Nan Liangliang , Sharf Andrei , Xie Ke , Wong Tien-Tsin , Deussen Oliver , Cohen-Or Daniel , Chen Baoquan
Published: November 2011

We present a method for structural summarization and abstraction of complex spatial arrangements found in architectural drawings. The method is based on the well-known Gestalt rules, which summarize how forms, patterns, and semantics are perceived by humans from bits and pieces of geometric information. Although defining a computational model for each rule alone has been extensively studied, modeling a conjoint of Gestalt rules remains a challenge. In this work, we develop a computational framework which models Gestalt rules and more importantly, their complex interactions. We apply
conjoining rules
to line drawings, to detect groups of objects and repetitions that conform to Gestalt principles. We summarize and abstract such groups in ways that maintain structural semantics by displaying only a reduced number of repeated elements, or by replacing them with simpler shapes. We show an application of our method to line drawings of architectural models of various styles, and the potential of extending the technique to other computer-generated illustrations, and three-dimensional models.
C1x6
Authors: Kulik Alexander , Kunert André , Beck Stephan , Reichel Roman , Blach Roland , Zink Armin , Froehlich Bernd
Published: November 2011

Stereoscopic multi-user systems provide multiple users with individual views of a virtual environment. We developed a new projection-based stereoscopic display for six users, which employs six customized DLP projectors for fast time-sequential image display in combination with polarization. Our intelligent high-speed shutter glasses can be programmed from the application to adapt to the situation. For instance, it does this by staying open if users do not look at the projection screen or switch to a VIP high brightness mode if less than six users use the system. Each user is tracked and can move freely in front of the display while perceiving perspectively correct views of the virtual environment.

Navigating a group of six users through a virtual world leads to situations in which the group will not fit through spatial constrictions. Our augmented group navigation techniques ameliorate this situation by fading out obstacles or by slightly redirecting individual users along a collision-free path. While redirection goes mostly unnoticed, both techniques temporarily give up the notion of a consistent shared space. Our user study confirms that users generally prefer this trade-off over naïve approaches.
Spermatic Cord Knot: A Clinical Finding in Patients with Spermatic Cord Torsion
Authors: Al-Terki Abdullatif , Al-Qaoud Talal
Published: November 2011

Pertinent history taking and careful examination often taper the differentials of the acute scrotum; congruently the ability to diagnose acute spermatic cord torsion (SCT) when radiological adjuncts are not available is highly imperative. This observational study serves to present a series of 46 cases of spermatic cord torsion whereby we hypothesize the identification of a clinical knot on scrotal examination as an important clinical aid in making a decision to surgical exploration in patients with acute and subacute SCT, especially in centers where imaging resources are unavailable.
When Cells Suffocate: Autophagy in Cancer and Immune Cells under Low Oxygen
Authors: Schlie Katrin , Spowart Jaeline E. , Hughson Luke R. K. , Townsend Katelin N. , Lum Julian J.
Published: November 2011

Hypoxia is a signature feature of growing tumors. This cellular state creates an inhospitable condition that impedes the growth and function of all cells within the immediate and surrounding tumor microenvironment. To adapt to hypoxia, cells activate autophagy and undergo a metabolic shift increasing the cellular dependency on anaerobic metabolism. Autophagy upregulation in cancer cells liberates nutrients, decreases the buildup of reactive oxygen species, and aids in the clearance of misfolded proteins. Together, these features impart a survival advantage for cancer cells in the tumor microenvironment. This observation has led to intense research efforts focused on developing autophagy-modulating drugs for cancer patient treatment. However, other cells that infiltrate the tumor environment such as immune cells also encounter hypoxia likely resulting in hypoxia-induced autophagy. In light of the fact that autophagy is crucial for immune cell proliferation as well as their effector functions such as antigen presentation and T cell-mediated killing of tumor cells, anticancer treatment strategies based on autophagy modulation will need to consider the impact of autophagy on the immune system.
Bioassay-Guided Isolation of Cytotoxic Cycloartane Triterpenoid Glycosides from the Traditionally Used Medicinal PlantLeea indica
Authors: Wong Yau Hsiung , Abdul Kadir Habsah , Ling Sui Kiong
Published: November 2011

Leea indicais a medicinal plant used traditionally to cure cancer. In this study, the cytotoxic compounds ofL. indicawere isolated using bioassay-guided approach. Two cycloartane triterpenoid glycosides, mollic acid arabinoside (MAA) and mollic acid xyloside (MAX), were firstly isolated fromL. indica. They inhibited the growth of Ca Ski cervical cancer cells with IC50of 19.21 μM (MAA) and 33.33 μM (MAX). MRC5 normal cell line was used to calculate selectivity index. MAA and MAX were about 8 and 4 times more cytotoxic to Ca Ski cells compared to MRC5. The cytotoxicity of MAA was characterized by both cytostatic and cytocidal effects. MAA decreased the expression of proliferative cell nuclear antigen, increased sub-G1 cells, and arrested cells in S and G2/M phases. This study provides the evidence for the ethnomedicinal use ofL. indicaand paves the way for future mechanism studies on the anticancer effects of MAA.
Intermediate-Term Efficacy of Tm:YAG Laser Prostate Vaporesection for Bladder Outlet Obstruction: Initial Experience from a UK Teaching Hospital
Authors: Pal Raj P. , Khan Masood A.
Published: November 2011

Objectives: To assess the safety and clinical efficacy of Tm:YAG laser vaporesection of the prostate (ThuVaRP) at intermediate-term follow-up. Patients and Methods: We identified the first 60 consecutive patients who underwent ThuVaRP at our institute. Operative outcomes assessed were resection time, resection weight, drop in haemoglobin, transfusion rate, catheter time and complication rate. The International Prostate Symptom Score (IPSS) was documented at a mean follow-up period of 19 months postoperatively. Results: 45/60 patients underwent treatment due to lower urinary tract symptoms secondary to benign prostatic obstruction, 11/60 patients had a long-term catheter in situ for refractory urinary retention secondary to benign prostatic obstruction, and 4/60 patients had bladder outflow obstruction secondary to adenocarcinoma of the prostate. 1/60 patients developed urosepsis, 1/60 patients developed a urinary tract infection and 1/60 patients required 3-way catheterization and irrigation due to haematuria. No patients required a blood transfusion. The mean IPSS at a mean follow-up interval of 19 months (range 15–28 months) was 5.1 (range 1–23). Postoperative maximum flow rate improved from 7.9 to 17.1 ml/s, and post-micturition residual volume decreased from 254 to 86 ml. Conclusion: ThuVaRP is safe and appears to have durable efficacy at intermediate follow-up.
Effect of Alzheimer Caregiving on Circulating Levels of C-Reactive Protein and Other Biomarkers Relevant to Cardiovascular Disease Risk: A Longitudinal Study
Authors: von Känel Roland , Mills Paul J. , Mausbach Brent T. , Dimsdale Joel E. , Patterson Thomas L. , Ziegler Michael G. , Ancoli-Israel Sonia , Allison Matthew , Chattillion Elizabeth A. , Grant Igor
Published: November 2011

Background: Providing care to a spouse with Alzheimer’s disease (AD) may contribute to cardiovascular disease (CVD). The acute phase reactant C-reactive protein (CRP) is a well-established biomarker of an increased CVD risk. Objective: To investigate the hypothesis that dementia caregiving is associated with elevated circulating levels of CRP and possibly other biomarkers of CVD risk. Methods: We examined 118 elderly spousal Alzheimer caregivers and 51 noncaregiving controls about once a year for up to 3 years. Random regression models with fixed and time-variant effects for a range of covariates known to affect biomarker levels were used to evaluate changes in CRP and in 12 additional measures of inflammation, cellular adhesion, endothelial function, and hemostasis in relation to caregiving status, years of caregiving, and major transitions in the caregiving situation. Results: During the study period, longer duration of caregiving was associated with elevated CRP levels (p = 0.040) and caregivers showed greater tumor necrosis factor (TNF)-α levels than controls (p = 0.048). Additionally, 3 months after the death of the AD spouse, caregivers showed a significant drop in CRP levels (p = 0.003) and levels of soluble intercellular adhesion molecule (sICAM)-1 (p = 0.008). Conclusion: Duration of caregiving and being a caregiver per se were both associated with chronic low-grade inflammation as indicated by elevated CRP and TNF-α levels, respectively. Conversely, death of the AD spouse was associated with lower CRP and sICAM-1 levels. The findings indicate that chronic caregiving of those with dementia may result in increased inflammation and, thereby, possibly increased CVD risk.
A New Vasculitis Activity Score for Predicting Death in Myeloperoxidase-Antineutrophil Cytoplasmic Antibody-Associated Vasculitis Patients
Authors: Koike Kiyomi , Fukami Kei , Yonemoto Koji , Iwatani Ryuji , Obata Rimi , Ueda Kaoru , Toyonaga Maki , Ueda Seiji , Ohara Atsuko , Takeda Kazuhito , Yamagishi Sho-ichi , Okuda Seiya
Published: November 2011

Background/Aims: Myeloperoxidase-antineutrophil cytoplasmic antibody (MPO-ANCA)-positive microscopic polyangiitis patients with renal involvement have been shown to have a progressive clinical course. In this study, we compared the clinical utility of the Japanese Vasculitis Activity Score (JVAS) with the Birmingham Vasculitis Activity Score (BVAS) for predicting death in patients with MPO-ANCA-associated renal involvement. Methods: Sixty-nine patients with MPO-ANCA-associated vasculitis with renal involvement (22 males and 47 females, age 69.8 ± 8.7 years) were enrolled in this study. We retrospectively investigated which score was better for predicting the poor prognosis of patients. Results: The mortality rate of the patients within 2 years after disease onset was 33% (23/69). JVAS was not correlated with BVAS. Univariate logistic regression analysis for death showed that the odds ratio (OR) of JVAS was statistically significant (OR 1.76, 95% confidence interval, CI, 1.29–2.41, p < 0.001), while that of BVAS was not (OR 1.07, 95% CI 0.98–1.16, p = 0.14). Moreover, a multivariate model showed that JVAS was an independent determinant of death (OR 1.59, 95% CI 1.12–2.25, p = 0.009). The area under the receiver operating characteristic curve for JVAS was 0.778, which was significantly larger (p = 0.02) than that for BVAS (0.586). The estimated optimal cut-off point of JVAS for the prediction of death was 5. At this point, the sensitivity was 82.6% and the specificity was 60.9%. Conclusion: We demonstrated that compared with BVAS, JVAS was a simpler and more reliable measure for predicting death in patients with MPO-ANCA-associated vasculitis with renal involvement.