@misc{3463, abstract = {It is widely accepted that the hippocampus plays a major role in learning and memory. The mossy fiber synapse between granule cells in the dentate gyrus and pyramidal neurons in the CA3 region is a key component of the hippocampal trisynaptic circuit. Recent work, partially based on direct presynaptic patch-clamp recordings from hippocampal mossy fiber boutons, sheds light on the mechanisms of synaptic transmission and plasticity at mossy fiber synapses. A high Na(+) channel density in mossy fiber boutons leads to a large amplitude of the presynaptic action potential. Together with the fast gating of presynaptic Ca(2+) channels, this generates a large and brief presynaptic Ca(2+) influx, which can trigger transmitter release with high efficiency and temporal precision. The large number of release sites, the large size of the releasable pool of vesicles, and the huge extent of presynaptic plasticity confer unique strength to this synapse, suggesting a large impact onto the CA3 pyramidal cell network under specific behavioral conditions. The characteristic properties of the hippocampal mossy fiber synapse may be important for pattern separation and information storage in the dentate gyrus-CA3 cell network.}, author = {Bischofberger, Joseph and Engel, Dominique and Frotscher, Michael and Peter Jonas}, booktitle = {Pflugers Archiv : European Journal of Physiology}, number = {3}, pages = {361 -- 372}, publisher = {Springer}, title = {{Timing and efficacy of transmitter release at mossy fiber synapses in the hippocampal network. (Review)}}, doi = {10.1007/s00424-006-0093-2}, volume = {453}, year = {2006}, } @inproceedings{3499, abstract = {We study infinite stochastic games played by n-players on a finite graph with goals specified by sets of infinite traces. The games are concurrent (each player simultaneously and independently chooses an action at each round), stochastic (the next state is determined by a probability distribution depending on the current state and the chosen actions), infinite (the game continues for an infinite number of rounds), nonzero-sum (the players’ goals are not necessarily conflicting), and undiscounted. We show that if each player has an upward-closed objective, then there exists an ε-Nash equilibrium in memoryless strategies, for every ε>0; and exact Nash equilibria need not exist. Upward-closure of an objective means that if a set Z of infinitely repeating states is winning, then all supersets of Z of infinitely repeating states are also winning. Memoryless strategies are strategies that are independent of history of plays and depend only on the current state. We also study the complexity of finding values (payoff profile) of an ε-Nash equilibrium. We show that the values of an ε-Nash equilibrium in nonzero-sum concurrent games with upward-closed objectives for all players can be computed by computing ε-Nash equilibrium values of nonzero-sum concurrent games with reachability objectives for all players and a polynomial procedure. As a consequence we establish that values of an ε-Nash equilibrium can be computed in TFNP (total functional NP), and hence in EXPTIME. }, author = {Krishnendu Chatterjee}, pages = {271 -- 286}, publisher = {Springer}, title = {{Nash equilibrium for upward-closed objectives}}, doi = {10.1007/11874683_18}, volume = {4207}, year = {2006}, } @inproceedings{3500, abstract = {The classical algorithm for solving Bu ̈chi games requires time O(n · m) for game graphs with n states and m edges. For game graphs with constant outdegree, the best known algorithm has running time O(n2/logn). We present two new algorithms for Bu ̈chi games. First, we give an algorithm that performs at most O(m) more work than the classical algorithm, but runs in time O(n) on infinitely many graphs of constant outdegree on which the classical algorithm requires time O(n2). Second, we give an algorithm with running time O(n · m · log δ(n)/ log n), where 1 ≤ δ(n) ≤ n is the outdegree of the game graph. Note that this algorithm performs asymptotically better than the classical algorithm if δ(n) = O(log n).}, author = {Krishnendu Chatterjee and Thomas Henzinger and Piterman, Nir}, publisher = {ACM}, title = {{Algorithms for Büchi Games}}, year = {2006}, } @misc{3510, abstract = {Embodiments automatically generate an accurate network of watertight NURBS patches from polygonal models of objects while automatically detecting and preserving character lines thereon. These embodiments generate from an initial triangulation of the surface, a hierarchy of progressively coarser triangulations of the surface by performing a sequence of edge contractions using a greedy algorithm that selects edge contractions by their numerical properties. Operations are also performed to connect the triangulations in the hierarchy using homeomorphisms that preserve the topology of the initial triangulation in the coarsest triangulation. A desired quadrangulation of the surface can then be generated by homeomorphically mapping edges of a coarsest triangulation in the hierarchy back to the initial triangulation. This quadrangulation is topologically consistent with the initial triangulation and is defined by a plurality of quadrangular patches. These quadrangular patches are linked together by a (U, V) mesh that is guaranteed to be continuous at patch boundaries. A grid is then preferably fit to each of the quadrangles in the resulting quadrangulation by decomposing each of the quadrangles into k.sup.2 smaller quadrangles. A watertight NURBS model may be generated from the resulting quadrangulation.}, author = {Edelsbrunner, Herbert and Fu, Ping and Nekhayev, Dmitry and Facello, Michael and Williams, Steven}, title = {{Method, apparatus and computer program products for automatically generating NURBS models of triangulated surfaces using homeomorphism}}, year = {2006}, } @misc{3511, abstract = {Methods, apparatus and computer program products provide efficient techniques for designing and printing shells of hearing-aid devices with a high degree of quality assurance and reliability and with a reduced number of manual and time consuming production steps and operations. These techniques also preferably provide hearing-aid shells having internal volumes that can approach a maximum allowable ratio of internal volume relative to external volume. These high internal volumes facilitate the inclusion of hearing-aid electrical components having higher degrees of functionality and/or the use of smaller and less conspicuous hearing-aid shells. A preferred method includes operations to generate a watertight digital model of a hearing-aid shell by thickening a three-dimensional digital model of a shell surface in a manner that eliminates self-intersections and results in a thickened model having an internal volume that is a high percentage of an external volume of the model. }, author = {Fu, Ping and Nekhayev, Dmitry and Edelsbrunner, Herbert}, title = {{Manufacturing methods and systems for rapid production of hearing-aid shells}}, year = {2006}, } @misc{3512, abstract = {Methods, apparatus and computer program products provide efficient techniques for reconstructing surfaces from data point sets. These techniques include reconstructing surfaces from sets of scanned data points that have preferably undergone preprocessing operations to improve their quality by, for example, reducing noise and removing outliers. These techniques include reconstructing a dense and locally two-dimensionally distributed 3D point set (e.g., point cloud) by merging stars in two-dimensional weighted Delaunay triangulations within estimated tangent planes. The techniques include determining a plurality of stars from a plurality of points p.sub.i in a 3D point set S that at least partially describes the 3D surface, by projecting the plurality of points p.sub.i onto planes T.sub.i that are each estimated to be tangent about a respective one of the plurality of points p.sub.i. The plurality of stars are then merged into a digital model of the 3D surface.}, author = {Fletcher, Yates and Gloth, Tobias and Edelsbrunner, Herbert and Fu, Ping}, title = {{Method, apparatus and computer products that reconstruct surfaces from data points}}, year = {2006}, } @article{3545, abstract = {The functional organization of the basal ganglia ( BG) is often defined according to one of two opposing schemes. The first proposes multiple, essentially independent channels of information processing. The second posits convergence and lateral integration of striatal channels at the level of the globus pallidus ( GP). We tested the hypothesis that these proposed aspects of functional connectivity within the striatopallidal axis are dynamic and related to brain state. Local field potentials ( LFPs) were simultaneously recorded from multiple sites in striatum and GP in anesthetized rats during slow-wave activity( SWA) and during global activation evoked by sensory stimulation. Functional connectivity was inferred from comparative analyses of the internuclear and intranuclear coherence between bipolar derivations of LFPs. During prominent SWA, as shown in the electrocorticogram and local field potentials in the basal ganglia, intranuclear coherence, and, thus, lateral functional connectivity within striatum or globus pallidus was relatively weak. Furthermore, the temporal coupling of LFPs recorded across these two nuclei involved functional convergence at the level of GP. Global activation, indicated by a loss of SWA, was accompanied by a rapid functional reorganization of the striatopallidal axis. Prominent lateral functional connectivity developed within GP and, to a significantly more constrained spatial extent, striatum. Additionally, functional convergence on GP was no longer apparent, despite increased internuclear coherence. These data demonstrate that functional connectivity within the BG is highly dynamic and suggest that the relative expression of organizational principles, such as parallel, independent processing channels, striatopallidal convergence, and lateral integration within BG nuclei, is dependent on brain state.}, author = {Magill,Peter J and Pogosyan,Alek and Sharott,Andrew and Jozsef Csicsvari and Bolam, John Paul and Brown,Peter}, journal = {Journal of Neuroscience}, number = {23}, pages = {6318 -- 6329}, publisher = {Society for Neuroscience}, title = {{Changes in functional connectivity within the rat striatopallidal axis during global brain activation in vivo}}, doi = {10.1523/​JNEUROSCI.0620-06.2006}, volume = {26}, year = {2006}, } @inproceedings{3559, abstract = {Persistent homology is the mathematical core of recent work on shape, including reconstruction, recognition, and matching. Its per- tinent information is encapsulated by a pairing of the critical values of a function, visualized by points forming a diagram in the plane. The original algorithm in [10] computes the pairs from an ordering of the simplices in a triangulation and takes worst-case time cubic in the number of simplices. The main result of this paper is an algorithm that maintains the pairing in worst-case linear time per transposition in the ordering. A side-effect of the algorithm’s anal- ysis is an elementary proof of the stability of persistence diagrams [7] in the special case of piecewise-linear functions. We use the algorithm to compute 1-parameter families of diagrams which we apply to the study of protein folding trajectories.}, author = {Cohen-Steiner, David and Herbert Edelsbrunner and Morozov, Dmitriy}, pages = {119 -- 126}, publisher = {ACM}, title = {{Vines and vineyards by updating persistence in linear time}}, doi = {10.1145/1137856.1137877}, year = {2006}, } @inproceedings{3560, abstract = {We continue the study of topological persistence [5] by investigat- ing the problem of simplifying a function f in a way that removes topological noise as determined by its persistence diagram [2]. To state our results, we call a function g an ε-simplification of another function f if ∥f − g∥∞ ≤ ε, and the persistence diagrams of g are the same as those of f except all points within L1-distance at most ε from the diagonal have been removed. We prove that for func- tions f on a 2-manifold such ε-simplification exists, and we give an algorithm to construct them in the piecewise linear case.}, author = {Herbert Edelsbrunner and Morozov, Dmitriy and Pascucci, Valerio}, pages = {127 -- 134}, publisher = {ACM}, title = {{Persistence-sensitive simplification of functions on 2-manifolds}}, doi = {10.1145/1137856.1137878}, year = {2006}, } @misc{3594, author = {Pemberton, Josephine M and Swanson, Graeme M and Nicholas Barton and Livingstone, Suzanne R and Senn, Helen V}, booktitle = {Deer}, number = {9}, pages = {22 -- 26}, publisher = {BDS }, title = {{Hybridisation between red and sika deer in Scotland}}, volume = {13}, year = {2006}, } @article{3609, abstract = {Bombina bombina and B. variegata are two anciently diverged toad taxa that have adapted to different breeding habitats yet hybridize freely in zones of overlap where their parapatric distributions meet. Here, we report on a joint genetic and ecological analysis of a hybrid zone in the vicinity of Stryi in western Ukraine. We used five unlinked allozyme loci, two nuclear single nucleotide polymorphisms and a mitochondrial DNA haplotype as genetic markers. Parallel allele frequency clines with a sharp central step occur across a sharp ecotone, where transitions in aquatic habitat, elevation, and terrestrial vegetation coincide. The width of the hybrid zone, estimated as the inverse of the maximum gradient in allele frequency, is 2.3 km. This is the smallest of four estimates derived from different clinal transects across Europe. We argue that the narrow cline near Stryi is mainly due to a combination of habitat distribution and habitat preference. Adult toads show a preference for either ponds (B. bombina) or puddles (B. variegata), which is known to affect the distribution of genotypes within the hybrid zones. At Stryi, it should cause a reduction of the dispersal rate across the ecotone and thus narrow the cline. A detailed comparison of all five intensively studied Bombina transects lends support to the hypothesis that habitat distribution plus habitat preference can jointly affect the structure of hybrid zones and, ultimately, the resulting barriers to gene flow between differentiated gene pools. This study also represents a resampling of an area that was last studied more than 70 years ago. Our allele-frequency clines largely coincide with those that were described then on the basis of morphological variation. However, we found asymmetrical introgression of B. variegata genes into B. bombina territory along the bank of a river.}, author = {Yanchukov, Alexey and Hofman, Sebastian and Szymura, Jacek M and Mezhzherin, Sergey V and Morozov-Leonov, Sviatoslav and Nicholas Barton and Nürnberger, Beate}, journal = {Evolution; International Journal of Organic Evolution}, number = {3}, pages = {583 -- 600}, publisher = {Wiley-Blackwell}, title = {{Hybridization of Bombina bombina and B. variegata (Anura, Discoglossidae) at a sharp ecotone in western Ukraine: comparisons across transects and over time}}, doi = {10.1111/j.0014-3820.2006.tb01139.x}, volume = {60}, year = {2006}, } @article{3608, abstract = {We study the evolution of inversions that capture locally adapted alleles when two populations are exchanging migrants or hybridizing. By suppressing recombination between the loci, a new inversion can spread. Neither drift nor coadaptation between the alleles (epistasis) is needed, so this local adaptation mechanism may apply to a broader range of genetic and demographic situations than alternative hypotheses that have been widely discussed. The mechanism can explain many features observed in inversion systems. It will drive an inversion to high frequency if there is no countervailing force, which could explain fixed differences observed between populations and species. An inversion can be stabilized at an intermediate frequency if it also happens to capture one or more deleterious recessive mutations, which could explain polymorphisms that are common in some species. This polymorphism can cycle in frequency with the changing selective advantage of the locally favored alleles. The mechanism can establish underdominant inversions that decrease heterokaryotype fitness by several percent if the cause of fitness loss is structural, while if the cause is genic there is no limit to the strength of underdominance that can result. The mechanism is expected to cause loci responsible for adaptive species-specific differences to map to inversions, as seen in recent QTL studies. We discuss data that support the hypothesis, review other mechanisms for inversion evolution, and suggest possible tests. }, author = {Kirkpatrick, Mark and Nicholas Barton}, journal = {Genetics}, number = {1}, pages = {419 -- 434}, publisher = {Genetics Society of America}, title = {{Chromosome inversions, local adaptation, and speciation}}, doi = {10.1534/genetics.105.047985}, volume = {173}, year = {2006}, } @article{3610, abstract = {For a model of diallelic loci with arbitrary epistasis, Barton and Turelli [2004. Effects of genetic drift on variance components under a general model of epistasis. Evolution 58, 2111–2132] gave results for variances among and within replicate lines obtained by inbreeding without selection. Here, we discuss the relation between their population genetic methods and classical quantitative genetic arguments. In particular, we consider the case of no dominance using classical identity by descent arguments, which generalizes their results from two alleles to multiple alleles. To clarify the connections between the alternative methods, we obtain the same results using an intermediate method, which explicitly identifies the statistical effects of sets of loci. We also discuss the effects of population bottlenecks on covariances among relatives.}, author = {Hill, William G and Nicholas Barton and Turelli, Michael}, journal = {Theoretical Population Biology}, number = {1}, pages = {56 -- 62}, publisher = {Academic Press}, title = {{Prediction of effects of genetic drift on variance components under a general model of epistasis}}, doi = {10.1016/j.tpb.2005.10.001}, volume = {70}, year = {2006}, } @inproceedings{3679, abstract = {This paper describes a new system for "Finding Satellite Tracks” in astronomical images based on the modern geometric approach. There is an increasing need of using methods with solid mathematical and statistical foundation in astronomical image processing. Where the computational methods are serving in all disciplines of science, they are becoming popular in the field of astronomy as well. Currently different computational systems are required to be numerically optimized before to get applied on astronomical images. So at present there is no single system which solves the problems of astronomers using computational methods based on modern approaches. The system "Finding Satellite Tracks” is based on geometric matching method "Recognition by Adaptive Subdivision of Transformation Space (RAST)".}, author = {Ali,Haider and Christoph Lampert and Breuel,Thomas M}, pages = {892 -- 901}, publisher = {Springer}, title = {{Satellite tracks removal in astronomical images}}, doi = {10.1007/11892755_92}, volume = {4225}, year = {2006}, } @inproceedings{3677, abstract = {We propose a video retrieval framework based on a novel combination of spatiograms and the Jensen-Shannon divergence, and validate its performance in two quantitative experiments on TRECVID BBC Rushes data. In the first experiment, color-based methods are tested by grouping redundant shots in an unsupervised clustering. Results of the second experiment show that motion-based spatiograms make a promising fast, compressed-domain descriptor for the detection of interview scenes.}, author = {Ulges, Adrian and Christoph Lampert and Keysers,Daniel}, pages = {1 -- 10}, publisher = {NIST (National Institute of Standards and Technology, US Department of Commerce)}, title = {{Spatiogram-based shot distances for video retrieval}}, year = {2006}, } @inproceedings{3680, abstract = {The detection of counterfeit in printed documents is currently based mainly on built-in security features or on human expertise. We propose a classification system that supports non-expert users to distinguish original documents from PC-made forgeries by analyzing the printing technique used. Each letter in a document is classified using a support vector machine that has been trained to distinguish laser from inkjet printouts. A color-coded visualization helps the user to interpret the per-letter classification results}, author = {Christoph Lampert and Mei,Lin and Breuel,Thomas M}, pages = {639 -- 634}, publisher = {IEEE}, title = {{Printing technique classification for document counterfeit detection}}, doi = {10.1109/ICCIAS.2006.294214}, volume = {1}, year = {2006}, } @article{3695, abstract = {We give an analytical and geometrical treatment of what it means to separate a Gaussian kernel along arbitrary axes in Ropfn, and we present a separation scheme that allows us to efficiently implement anisotropic Gaussian convolution filters for data of arbitrary dimensionality. Based on our previous analysis we show that this scheme is optimal with regard to the number of memory accesses and interpolation operations needed. The proposed method relies on nonorthogonal convolution axes and works completely in image space. Thus, it avoids the need for a fast Fourier transform (FFT)-subroutine. Depending on the accuracy and speed requirements, different interpolation schemes and methods to implement the one-dimensional Gaussian (finite impulse response and infinite impulse response) can be integrated. Special emphasis is put on analyzing the performance and accuracy of the new method. In particular, we show that without any special optimization of the source code, it can perform anisotropic Gaussian filtering faster than methods relying on the FFT.}, author = {Christoph Lampert and Wirjadi,Oliver}, journal = {IEEE Transactions on Image Processing (TIP)}, number = {11}, pages = {3501 -- 3513}, publisher = {IEEE}, title = {{An optimal non-orthogonal separation of the anisotropic Gaussian convolution filter}}, doi = { 10.1109/TIP.2006.877501 }, volume = {15}, year = {2006}, } @inproceedings{3693, abstract = {Gaussian filtering in one, two or three dimensions is among the most commonly needed tasks in signal and image processing. Finite impulse response filters in the time domain with Gaussian masks are easy to implement in either floating or fixed point arithmetic, because Gaussian kernels are strictly positive and bounded. But these implementations are slow for large images or kernels. With the recursive IIR-filters and FFT-based methods, there are at least two alternative methods to perform Gaussian filtering in a faster way, but so far they are only applicable when floating-point hardware is available. In this paper, a fixed-point implementation of recursive Gaussian filtering is discussed and applied to isotropic and anisotropic image filtering by making use of a non-orthogonal separation scheme of the Gaussian filter.}, author = {Christoph Lampert and Wirjadi,Oliver}, pages = {1565 -- 1568}, publisher = {IEEE}, title = {{Anisotropic Gaussian filtering using fixed point arithmetic}}, doi = {10.1109/ICIP.2006.312606}, year = {2006}, } @inproceedings{3692, author = {Keysers,Daniel and Christoph Lampert and Breuel,Thomas M}, publisher = {SPIE}, title = {{Color image dequantization by constrained diffusion}}, doi = {10.1117/12.648713}, volume = {6058}, year = {2006}, } @article{3729, abstract = {Measuring the visco-elastic properties of biological macromolecules constitutes an important step towards the understanding of dynamic biological processes, such as cell adhesion, muscle function, or plant cell wall stability. Force spectroscopy techniques based on the atomic force microscope (AFM) are increasingly used to study the complex visco-elastic response of (bio-)molecules on a single-molecule level. These experiments either require that the AFM cantilever is actively oscillated or that the molecule is clamped at constant force to monitor thermal cantilever motion. Here we demonstrate that the visco-elasticity of single bio-molecules can readily be extracted from the Brownian cantilever motion during conventional force-extension measurements. It is shown that the characteristics of the cantilever determine the signal-to-noise (S/N) ratio and time resolution. Using a small cantilever, the visco-elastic properties of single dextran molecules were resolved with a time resolution of 8.3 ms. The presented approach can be directly applied to probe the dynamic response of complex bio-molecular systems or proteins in force-extension experiments.}, author = {Bippes, Christian A and Humphris, Andrew D and Stark, Martin and Mueller, Daniel J and Harald Janovjak}, journal = {European Biophysics Journal}, number = {3}, pages = {287 -- 292}, publisher = {Springer}, title = {{Direct measurement of single-molecule visco-elasticity in atomic force microscope force-extension experiments}}, doi = {10.1007/s00249-005-0023-9}, volume = {35}, year = {2006}, }