807 research outputs found
What's up prof? Current issues in the visual effects & post-production industry
We interviewed creative professionals at a number of London visual effects and post-production houses. We report on the key issues raised in those interviews: desirable new technologies, infrastructure challenges, personnel and process management
Feature-based terrain editing from complex sketches
We present a new method for first person sketch-based editing of terrain models. As in usual artistic pictures, the input sketch
depicts complex silhouettes with cusps and T-junctions, which typically correspond to non-planar curves in 3D. After analysing
depth constraints in the sketch based on perceptual cues, our method best matches the sketched silhouettes with silhouettes or ridges
of the input terrain. A deformation algorithm is then applied to the terrain, enabling it to exactly match the sketch from the given
perspective view, while insuring that none of the user-defined silhouettes is hidden by another part of the terrain. We extend this
sketch-based terrain editing framework to handle a collection of multi-view sketches. As our results show, this method enables
users to easily personalize an existing terrain, while preserving its plausibility and style.This work was conducted during an internship of Flora Ponjou Tasse at Inria Rhône-Alpes in Grenoble. It was partly supported by the ERC advanced grant EXPRESSIVE.This is the accepted manuscript. The final version is available from Elsevier at http://www.sciencedirect.com/science/article/pii/S009784931400081
Eye Movements and Attention for Behavioural Animation
This paper describes a simulation of attention behaviour aimed at computer-animated characters. Attention is the focusing of a
person’s perception on a particular object. This is useful for computer animation as it determines which objects the character is aware
of: information that can be used in the simulation of the character’s behaviour in order to automatically animate the character. The
simulation of attention also determines where the character is looking and so is used to produce gaze behaviou
A family of linearizable recurrences with the Laurent property
We consider a family of non-linear recurrences with the Laurent property. Although these recurrences are not generated by mutations in a cluster algebra, they fit within the broader framework of Laurent phenomenon algebras, as introduced recently by Lam and Pylyavskyy. Furthermore, each member of this family is shown to be linearizable in two different ways, in the sense that its iterates satisfy both a linear relation with constant coefficients and a linear relation with periodic coefficients. Associated monodromy matrices and first integrals are constructed, and the connection with the dressing chain for Schrödinger operators is also explained
Major role of pKpQIL-like plasmids in the early dissemination of KPC-type carbapenemases in the UK
Objectives: KPC-producing Enterobacteriaceae were first seen in the UK in 2003 and have been increasingly reported since 2010, largely owing to an ongoing outbreak in North-West England. We examined the role of clonal spread and plasmid transmission in their emergence. Methods: Isolates comprised KPC-positive Klebsiella pneumoniae (n=33), Escherichia coli (n=7) and Enterobacter spp. (n=4) referred to the national reference laboratory between 2008 and 2010 from 17 UK centres, including three in North-West England. Isolates were typed by MLST. Plasmids were transferred by electroporation and characterised by PCR or sequencing. PCR screening assays were developed to distinguish plasmid pKpQIL variants. Results: The K. pneumoniae isolates included 10 STs, of which three belonged to clonal group (CG) 258. CG258 (n=19) isolates were detected in 13 centres but accounted for only 7/19 (36.8%) of those from North-West England. Most KPC-producers (37/44, 84.1%), including 16/19 CG258 K. pneumoniae carried blaKPC on IncFIIK2 plasmids. Sequencing of a subset of these plasmids (n=11) revealed similarities with published pKpQIL. One variant, pKpQIL-UK - identified in K. pneumoniae CG258 (n=5) and ST468 (n=1) isolates from distinct centres - had only a few nucleotide changes from classical pKpQIL, whereas pKpQIL-D1 (n=1) and pKpQIL-D2 (n=4), from isolates of various species in the North-West, harboured large variations reflecting replacement of the partitioning and replication functions and potentially thereby facilitating spread. PCR revealed that 36/37 (97.3%) IncFIIK2-type plasmids in KPC-positive isolates had pKpQIL markers. Conclusions: pKpQIL-like plasmids played a major role in the early dissemination of KPC enzymes in the UK
MRL proteins cooperate with activated Ras in glia to drive distinct oncogenic outcomes
The Mig10/RIAM/Lpd (MRL) adapter protein Lpd regulates actin dynamics through interactions with Scar/WAVE and Ena/VASP proteins to promote the formation of cellular protrusions and to stimulate invasive migration. However, the ability of MRL proteins to interact with multiple actin regulators and to promote serum response factor (SRF) signalling has raised the question of whether MRL proteins employ alternative downstream mechanisms to drive oncogenic processes in a context-dependent manner. Here, using a Drosophila model, we show that overexpression of either human Lpd or its Drosophila orthologue Pico can promote growth and invasion of RasV12-induced cell tumours in the brain. Notably, effects were restricted to two populations of Repo-positive glial cells: an invasive population, characterized by JNK-dependent elevation of Mmp1 expression, and a hyperproliferative population lacking elevated JNK signalling. JNK activation was not triggered by reactive immune cell signalling, implicating the involvement of an intrinsic stress response. The ability to promote dissemination of RasV12-induced tumours was shared by a subset of actin regulators, including, most prominently, Chicadee/Profilin, which directly interacts with Pico, and, Mal, a cofactor for serum response factor that responds to changes in G:F actin dynamics. Suppression of Mal activity partially abrogated the ability of pico to promote invasion of RasV12 tumours. Furthermore, we found that larval glia are enriched for serum response factor expression, explaining the apparent sensitivity of glial cells to Pico/RasV12 overexpression. Taken together, our findings indicate that MRL proteins cooperate with oncogenic Ras to promote formation of glial tumours, and that, in this context, Mal/serum response factor activation is rate-limiting for tumour dissemination
Cluster-based point set saliency
© 2015 IEEE. We propose a cluster-based approach to point set saliency detection, a challenge since point sets lack topological information. A point set is first decomposed into small clusters, using fuzzy clustering. We evaluate cluster uniqueness and spatial distribution of each cluster and combine these values into a cluster saliency function. Finally, the probabilities of points belonging to each cluster are used to assign a saliency to each point. Our approach detects fine-scale salient features and uninteresting regions consistently have lower saliency values. We evaluate the proposed saliency model by testing our saliency-based keypoint detection against a 3D interest point detection benchmark. The evaluation shows that our method achieves a good balance between false positive and false negative error rates, without using any topological information
Cosmic cookery : making a stereoscopic 3D animated movie.
This paper describes our experience making a short stereoscopic movie visualizing the development of structure in
the universe during the 13.7 billion years from the Big Bang to the present day. Aimed at a general audience for
the Royal Society's 2005 Summer Science Exhibition, the movie illustrates how the latest cosmological theories
based on dark matter and dark energy are capable of producing structures as complex as spiral galaxies and
allows the viewer to directly compare observations from the real universe with theoretical results. 3D is an
inherent feature of the cosmology data sets and stereoscopic visualization provides a natural way to present the
images to the viewer, in addition to allowing researchers to visualize these vast, complex data sets.
The presentation of the movie used passive, linearly polarized projection onto a 2m wide screen but it was
also required to playback on a Sharp RD3D display and in anaglyph projection at venues without dedicated
stereoscopic display equipment. Additionally lenticular prints were made from key images in the movie. We
discuss the following technical challenges during the stereoscopic production process; 1) Controlling the depth
presentation, 2) Editing the stereoscopic sequences, 3) Generating compressed movies in display speci¯c formats.
We conclude that the generation of high quality stereoscopic movie content using desktop tools and equipment
is feasible. This does require careful quality control and manual intervention but we believe these overheads
are worthwhile when presenting inherently 3D data as the result is signi¯cantly increased impact and better
understanding of complex 3D scenes
Polymerase chain reaction amplified markers for bird sexing
Female birds are heterogametic (Z/W), while males are homogametic (Z/Z). PCR assays are often useful in sexing avian species, especially at hatch or in ovo. Two previously described assays are based on differences between the Z and W copy of the chicken chromodomain-helicase DNA-binding protein gene (CHD1Z and CHD1W). Applicability of these assays were tested in five other galliforms: red junglefowl, turkey, peafowl, bobwhite quail and common quail, and one waterfowl, mallard. Using primers described by Fridolfsson and Ellegren (1999), males of all galliform species studied displayed one 450-bp, Z-specific fragment, whereas females showed both CHD1Z (450-bp) and CHD1W (600-bp) fragments. Both mallard sexes yielded a single product of 600 bp. Using primers designed by Kahn and Quinn (1999), three species, red junglefowl, turkey and peafowl, displayed one Z-specific fragment (240 bp) in males and two fragments (240 and 265 bp) in females. Only a single fragment was obtained, irrespective of sex, in bobwhite quail (250 bp), common quail (275 bp) and mallard (240 bp). By screening a chicken BAC library with a CHD1W genomic fragment, two overlapping BAC inserts were obtained that, by PCR analysis, appear to contain the chicken CHD1Z gene. To date, we have been unable to identify a CHD1W-containing BAC in our library. Additional BAC analysis is underway
Vortices in a Thin Film Superconductor with a Spherical Geometry
We report results from Monte Carlo simulations of a thin film superconductor
in a spherical geometry within the lowest Landau level approximation. We
observe the absence of a phase transition to a low temperature vortex solid
phase with these boundary conditions; the system remains in the vortex liquid
phase for all accessible temperatures. The correlation lengths are measured for
phase coherence and density modulation. Both lengths display identical
temperature dependences, with an asymptotic scaling form consistent with a
continuous zero temperature transition. This contrasts with the first order
freezing transition which is seen in the alternative quasi-periodic boundary
conditions. The high temperature perturbation theory and the ground states of
the spherical system suggest that the thermodynamic limit of the spherical
geometry is the same as that on the flat plane. We discuss the advantages and
drawbacks of simulations with different geometries, and compare with current
experimental conclusions. The effect of having a large scale inhomogeneity in
the applied field is also considered.Comment: This replacment contains substantial revisions: the new article is
twice as long with new and different results on the thermodynamic limit on
the sphere plus a full discussion on the alternative boundary conditions used
in simulations in the LLL approximation. 19 pages, 12 encapsulated PostScript
figures, 1 JPEG figure, uses RevTeX (with epsf
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