bluuebunny/crossref_metadata_2025_split huggingface dataset:
Sex‐dependent differences in behavior and hippocampal neurogenesis after irradiation to the young mouse brain
Authors: Roughton Karolina , Kalm Marie , Blomgren Klas 
Published: July 2012

AbstractCranial radiotherapy in the treatment of pediatric malignancies may lead to cognitive deficits, and girls suffer more severe deficits than boys. However, most experimental studies are performed on male animals only. Our aim was to investigate possible long‐term gender differences in response to cranial irradiation (IR). Basal neurogenesis in non‐irradiated mice was higher in females but this was not apparent until the animals were adult. Male and female C57BL/6J mice received a single dose of 8 Gy to the whole brain on postnatal day 14 and were killed 6 h or 4 months later. Proliferation in the subgranular zone of the dentate gyrus in the hippocampus, as judged by the number of phosphohistone H3‐positive cells, was reduced by half 6 h after IR in both males and females. The reduced proliferation was still obvious 4 months after IR. Consequently, the continuous addition of new neurons to the granule cell layer (GCL) during brain growth was reduced in irradiated mice, and the reduction was more pronounced in females. This resulted in hampered growth of the GCL, reduced bromodeoxyuridine incorporation in adulthood, and severely reduced adult neurogenesis, as judged by the number of doublecortin‐positive cells in the GCL. In an open‐field test, locomotor activity was increased in both males and females after IR and anxiety levels were increased, more so in females. In an IntelliCage test, place learning was impaired by IR in females but not males.
Long‐lasting small‐amplitude TRP‐mediated dendritic depolarizations in CA1 pyramidal neurons are intrinsically stable and originate from distal tuft regions
Authors: Petersson Marcus E. , Fransén Erik 
Published: July 2012

AbstractIn several regions of the nervous system, neurons display bi‐ or multistable intrinsic properties. Such stable states may be subthreshold and long‐lasting, and can appear as a sustained afterdepolarization. In hippocampal CA1 pyramidal neurons, small‐amplitude (1 mV) long‐lasting (seconds) afterdepolarizations have been reported and are thought to depend on calcium‐activated nonselective (CAN) currents recently identified as transient receptor potential (TRP) channels. Continuing our previous experimental and computational work on synaptically metabotropic glutamate receptor (mGluR)‐activated TRP currents, we here explore small‐amplitude long‐lasting depolarizations in a detailed multicompartmental model of a CA1 pyramidal neuron. We confirm a previous hypothesis suggesting that the depolarization results from an interplay of TRP and voltage‐gated calcium channels, and contribute to the understanding of the depolarization in several ways. Specifically, we show that: (i) the long‐lasting depolarization may be intrinsically stable to weak excitatory and inhibitory input, (ii) the phenomenon is essentially located in distal apical dendrites, (iii) induction is facilitated if simultaneous input arrives at several dendritic branches, and if calcium‐ and/or mGluR‐evoked signals undergo summation, suggesting that both spatial and temporal synaptic summation might be required for the depolarization to occur and (iv) we also show that the integration of inputs to oblique dendrites is strongly modulated by the presence of small‐amplitude long‐lasting depolarizations in distal tuft dendrites. To conclude, we suggest that small‐amplitude long‐lasting dendritic depolarizations may contribute to sustaining neural information during behavioural tasks in cases where information is separated in time, as in trace conditioning and delay tasks.
Pattern‐motion selective responses in MT, MST and the pulvinar of humans
Authors: Villeneuve M. Y. , Thompson B. , Hess R. F. , Casanova C. 
Published: July 2012

AbstractPlaid stimuli are often used to investigate the mechanisms involved in the integration and segregation of motion information. Considering the perceptual importance of such mechanisms, only a very limited number of visual brain areas have been found to be specifically involved in motion integration. These are the human (h)MT+ complex, area V3 and the pulvinar. The hMT+ complex can be functionally subdivided into two separate areas, middle temporal area (MT) and medial superior temporal area (MST); however, it is currently unclear whether these distinct sub‐regions have different responses to plaid stimuli. To address this issue we used functional magnetic resonance imaging to quantify the relative response of MT and MST to component and pattern motion. Participants viewed plaid stimuli that were constrained to result in the perception of either component motion (segregation of motion information) or pattern motion (integration of motion information). MT/MST segregation was achieved using a moving dot stimulus that allowed stimulation of each visual hemifield either in unison or separately. We found pattern motion selective responses in both MT and MST. Consistent with previous reports, activity indicative of pattern motion selectivity was also found in the pulvinar as well as in other extrastriate areas. These results demonstrate that MT, MST and the pulvinar are involved in the complex motion integration mechanisms that are triggered by plaid stimuli. This reinforces the concept that integrative computations take place in a distributed neuronal circuit both in cortical and sub‐cortical networks.
Incidence and predictors of difficult laryngoscopy in 11.219 pediatric anesthesia procedures
Authors: Heinrich Sebastian , Birkholz Torsten , Ihmsen Harald , Irouschek Andrea , Ackermann Andreas , Schmidt Joachim 
Published: July 2012

SummaryObjective:  Difficult laryngoscopy in pediatric patients undergoing anesthesia.Aim:  This retrospective analysis was conducted to investigate incidence and predictors of difficult laryngoscopy in a large cohort of pediatric patients receiving general anesthesia with endotracheal intubation.Background:  Young age and craniofacial dysmorphy are predictors for the difficult pediatric airway and difficult laryngoscopy. For difficult laryngoscopy, other general predictors are not yet described.Methods:  Retrospectively, from a 5‐year period, data from 11.219 general anesthesia procedures in pediatric patients with endotracheal intubation using age‐adapted Macintosh blades in a single center (university hospital) were analyzed statistically.Results:  The overall incidence of difficult laryngoscopy [Cormack and Lehane (CML) grade III and IV] was 1.35%. In patients younger than 1 year, the incidence of CML III or IV was significantly higher than in the older patients (4.7% vs 0.7%). ASA Physical Status III and IV, a higher Mallampati Score (III and IV) and a low BMI were all associated (P < 0.05) with difficult laryngoscopy. Patients undergoing oromaxillofacial surgery and cardiac surgery showed a significantly higher rate of CML III/IV findings.Conclusion:  The general incidence of difficult laryngoscopy in pediatric anesthesia is lower than in adults. Our results show that the risk of difficult laryngoscopy is much higher in patients below 1 year of age, in underweight patients and in ASA III and IV patients. The underlying disease might also contribute to the risk. If the Mallampati score could be obtained, prediction of difficult laryngoscopy seems to be reliable. Our data support the existing recommendations for a specialized anesthesiological team to provide safe anesthesia for infants and neonates.
Tracheal extubation of deeply anesthetized pediatric patients: a comparison of sevoflurane and sevoflurane in combination with low‐dose remifentanil
Authors: Shen Xia , Hu Chunbo , Li Wenxian 
Published: July 2012

SummaryPurpose:  We aimed to observe the emergence characteristics of children tracheally extubated in deep anesthesia with sevoflurane or sevoflurane in combination with low‐dose remifentanil.Methods:  We randomly allocated 50 pediatric patients undergoing elective electronic cochlear implantation to groups either receiving sevoflurane (Group S, n = 25), or sevoflurane plus low‐dose remifentanil (Group SR, n = 25), during extubation from anesthesia. In Group S, subjects were tracheally extubated while breathing 1.3 times the minimal effective concentration of sevoflurane. In Group SR, subjects were tracheally extubated while breathing 1.0 times the minimal effective concentration of sevoflurane with 0.02–0.05 μg·kg−1 per min remifentanil. Recovery characteristics and airway complications were noted.Results:  There was no significant difference in age, weight, sex, and duration of anesthesia. The average remifentanil rate was 0.036 μg·kg−1 per min, and compared with Group S, patients in Group SR had a lower respiratory rate (17.3 vs 20.2 per minute, P < 0.05) and a higher ETCO2 (52.3 vs 49.4 mmHg, P < 0.05). Oral airway usage was also less frequent in Group SR (44% vs 16%, P < 0.01). Additionally, the time from extubation to spontaneous eye opening was shorter in Group SR (10.9 min vs 19.6 min, P < 0.01). Finally, six patients in Group S and five patients in Group SR had a pediatric anesthesia emergence delirium score >10.Conclusions:  Low‐dose remifentanil in combination with sevoflurane provided rapid recovery and was safe for deep tracheal extubation in deep anesthesia in pediatric patients.
Per‐Vertex Defocus Blur for Stochastic Rasterization
Authors: Munkberg Jacob , Toth Robert , Akenine‐Möller Tomas 
Published: July 2012

AbstractWe present user‐controllable and plausible defocus blur for a stochastic rasterizer. We modify circle of confusion coefficients per vertex to express more general defocus blur, and show how the method can be applied to limit the foreground blur, extend the in‐focus range, simulate tilt‐shift photography, and specify per‐object defocus blur. Furthermore, with two simplifying assumptions, we show that existing triangle coverage tests and tile culling tests can be used with very modest modifications. Our solution is temporally stable and handles simultaneous motion blur and depth of field.
Pre‐convolved Radiance Caching
Authors: Scherzer Daniel , Nguyen Chuong H. , Ritschel Tobias , Seidel Hans‐Peter 
Published: July 2012

AbstractThe incident indirect light over a range of image pixels is often coherent. Two common approaches to exploit this inter‐pixel coherence to improve rendering performance are Irradiance Caching and Radiance Caching. Both compute incident indirect light only for a small subset of pixels (the cache), and later interpolate between pixels. Irradiance Caching uses scalar values that can be interpolated efficiently, but cannot account for shading variations caused by normal and reflectance variation between cache items. Radiance Caching maintains directional information, e.g., to allow highlights between cache items, but at the cost of storing and evaluating a Spherical Harmonics (SH) function per pixel. The arithmetic and bandwidth cost for this evaluation is linear in the number of coefficients and can be substantial. In this paper, we propose a method to replace it by an efficient per‐cache item pre‐filtering based on MIP maps — such as previously done for environment maps — leading to a single constant‐time lookup per pixel. Additionally, per‐cache item geometry statistics stored in distance‐MIP maps are used to improve the quality of each pixel's lookup. Our approximate interactive global illumination approach is an order of magnitude faster than Radiance Caching with Phong BRDFs and can be combined with Monte Carlo‐raytracing, Point‐based Global Illumination or Instant Radiosity.
Quantized Point‐Based Global Illumination
Authors: Buchholz Bert , Boubekeur Tamy 
Published: July 2012

AbstractPoint‐based global illumination (PBGI) uses a dense point sampling of the scene's surfaces to approximate indirect light transport and is intensively used in 3D motion pictures and special effects. Each point caches the reflected light using a spherical function and is typically used in a subsequent rasterization process to compute color bleeding and ambient occlusion in an economic, noise‐free fashion. The entire point set is organized in a spatial tree structure which models the light transport hierarchically, enabling fast adaptive shading on receivers (e.g., unprojected pixels). One of the major limitations of PBGI is related to the size of this tree, which can quickly become too large to fit in memory for complex scenes. However, we observe that, just as with natural images, this point data set is extremely redundant. In this paper, we present a new method exploiting this redundancy by factorizing PBGI data over the tree nodes. In particular, we show that a k‐means clustering in the parameter space of the spherical functions allows to define a small number of representative nodes against which any new one can be classified. These representative functions, gathered in a pre‐process over a subset of the actual points, form a look‐up table which allows to substitute node's data by quantized integers in a streaming process, avoiding building the full tree before compressing it. Depending on the nodes' spherical function variance in the scene and the desired accuracy, our indexed PBGI representation achieves between one and two orders of magnitude compression of the nodes spherical functions, with negligible numerical and perceptual error in the final image. In the case of a binary tree with one surfel per leaf and no spherical functions in the leaves, this leads to compression rates ranging from 3× to 5× for the whole tree.
Progressive Virtual Beam Lights
Authors: Novák Jan , Nowrouzezahrai Derek , Dachsbacher Carsten , Jarosz Wojciech 
Published: July 2012

AbstractA recent technique that forms virtual ray lights (VRLs) from path segments in media, reduces the artifacts common to VPL approaches in participating media, however, distracting singularities still remain. We present Virtual Beam Lights (VBLs), a progressive many‐lights algorithm for rendering complex indirect transport paths in, from, and to media. VBLs are efficient and can handle heterogeneous media, anisotropic scattering, and moderately glossy surfaces, while provably converging to ground truth. We inflate ray lights into beam lights with finite thicknesses to eliminate the remaining singularities. Furthermore, we devise several practical schemes for importance sampling the various transport contributions between camera rays, light rays, and surface points. VBLs produce artifact‐free images faster than VRLs, especially when glossy surfaces and/or anisotropic phase functions are present. Lastly, we employ a progressive thickness reduction scheme for VBLs in order to render results that converge to ground truth.
Intrinsic Images by Clustering
Authors: Garces Elena , Munoz Adolfo , Lopez‐Moreno Jorge , Gutierrez Diego 
Published: July 2012

AbstractDecomposing an input image into its intrinsic shading and reflectance components is a long‐standing ill‐posed problem. We present a novel algorithm that requires no user strokes and works on a single image. Based on simple assumptions about its reflectance and luminance, we first find clusters of similar reflectance in the image, and build a linear system describing the connections and relations between them. Our assumptions are less restrictive than widely‐adopted Retinex‐based approaches, and can be further relaxed in conflicting situations. The resulting system is robust even in the presence of areas where our assumptions do not hold. We show a wide variety of results, including natural images, objects from the MIT dataset and texture images, along with several applications, proving the versatility of our method.
Artistic Illumination Transfer for Portraits
Authors: Chen Xiaowu , Jin Xin , Zhao Qinping , Wu Hongyu 
Published: July 2012

AbstractRelighting a portrait in a single image is still a challenging problem, particularly when only a single artistic reference photograph or painting is provided. In this paper, we propose an artistic illumination transfer system for portraits based on a database of portrait images (photographs and paintings) associated with hand‐drawn illumination templates (276) by artists. Users can select a reference portrait image in the database, and the corresponding illumination template is transferred to an input portrait using image warping. Users can also provide reference portrait images those are not in the database. Based on the Face Illumination Descriptor (FID), the system selects from the database the reference image with the closest illumination to that of the user‐provided reference image and adjusts the corresponding illumination template to match the contrast of the user‐provided reference image. Experiments on not only paintings but also photographs, paper‐cuts and sketches demonstrate that convincing illumination transferred results can be rendered by our system.
Matting and Compositing for Fresnel Reflection on Wavy Surfaces
Authors: Endo Yuki , Kanamori Yoshihiro , Fukui Yukio , Mitani Jun 
Published: July 2012

AbstractThis paper introduces a framework that can extract an alpha matte from a single image with Fresnel reflection, and that can composite other objects with the image such that plausible reflections are included. Our method handles reflections in a plane with small undulations, for example, a water surface with waves or a glossy tabletop. During the matting stage, our method first estimates the transmission color, which is assumed to be uniform, and then calculates a reflection image and alpha matte based on user markups. However, accurate extraction of the matte becomes challenging when a plane has small undulations because these create perturbations in the matte. We therefore propose a filter that can refine the matte effectively. In the compositing stage, the reflection of a composited object is synthesized by ray tracing in real time. We demonstrate the effectiveness of our method through comparisons with ground‐truth data and results using natural images as inputs.
Geometry Presorting for Implicit Object Space Partitioning
Authors: Eisemann M. , Bauszat P. , Guthe S. , Magnor M. 
Published: July 2012

AbstractWe present a new data structure for object space partitioning that can be represented completely implicitly. The bounds of each node in the tree structure are recreated at run‐time from the scene objects contained therein. By applying a presorting procedure to the geometry, only a known fraction of the geometry is needed to locate the bounding planes of any node. We evaluate the impact of the implicit bounding plane representation and compare our algorithm to a classic bounding volume hierarchy. Though the representation is completely implicit, we still achieve interactive frame rates on commodity hardware.
Parameterization‐Aware MIP‐Mapping
Authors: Manson Josiah , Schaefer Scott 
Published: July 2012

AbstractWe present a method of generating mipmaps that takes into account the distortions due to the parameterization of a surface. Existing algorithms for generating mipmaps assume that the texture is isometrically mapped to the surface and ignore the actual surface parameterization. Our method correctly downsamples warped textures by assigning texels weights proportional to their area on a surface. We also provide a least‐squares approach to filtering over these warped domains that takes into account the postfilter used by the GPU. Our method improves texture filtering for most models but only modifies mipmap generation, requires no modification of art assets or rasterization algorithms, and does not affect run‐time performance.
A Stylized Approach for Pencil Drawing from Photographs
Authors: Yang Heekyung , Kwon Yunmi , Min Kyungha 
Published: July 2012

AbstractWe present a stylized scheme that produces pencil drawings in a range of styles from an image. To produce controllable pencil drawing effects and remedy the problems of existing convolution‐based schemes, we develop a swing bilateral LIC (SBL) filter. Our first approach to express the styled pencil drawings is to control the directions of pencil strokes that depicts both shapes and smooth tone. Another approach is to produce colors of pencil drawings by sampling colors from real color pencils. The third approach is to mimic the artistic technique that increases the details of drawings in a progressive manner. We present drawings in several styles and compare some of them directly with illustrations taken from an artists' work.
Surface Relief Analysis for Illustrative Shading
Authors: Ammann Lucas , Barla Pascal , Guennebaud Gaël , Granier Xavier , Reuter Patrick 
Published: July 2012

AbstractIn this paper, we present an analysis technique that leverages the complexity found in detailed 3D models for illustrative shading purposes. Given a smooth base surface with relief, it locates relief features (concavities, convexities and inflections) around each surface point and at multiple scales, using cubic‐polynomial fitting. This object‐space, per‐vertex information is then used to guide a variety of shading techniques including normal enhancement, feature visualization, accessibility shading and radiance scaling. Thanks to this approach, features at multiple scales are easily combined, filtered and shaded, allowing users to explore surface relief in real‐time.
A Statistical Method for SVBRDF Approximation from Video Sequences in General Lighting Conditions
Authors: Palma Gianpaolo , Callieri Marco , Dellepiane Matteo , Scopigno Roberto 
Published: July 2012

AbstractWe present a statistical method for the estimation of the Spatially Varying Bidirectional Reflectance Distribution Function (SVBRDF) of an object with complex geometry, starting from video sequences acquired with fixed but general lighting conditions. The aim of this work is to define a method that simplifies the acquisition phase of the object surface appearance and allows to reconstruct an approximated SVBRDF. The final output is suitable to be used with a 3D model of the object to obtain accurate and photo‐realistic renderings. The method is composed by three steps: the approximation of the environment map of the acquisition scene, using the same object as a probe; the estimation of the diffuse color of the object; the estimation of the specular components of the main materials of the object, by using a Phong model. All the steps are based on statistical analysis of the color samples projected by the video sequences on the surface of the object. Although the method presents some limitations, the trade‐off between the easiness of acquisition and the obtained results makes it useful for practical applications.