@inproceedings{3210,
abstract = {Luby and Rackoff showed how to construct a (super-)pseudo-random permutation {0,1}2n→ {0,1}2n from some number r of pseudo-random functions {0,1}n → {0,1}n. Their construction, motivated by DES, consists of a cascade of r Feistel permutations. A Feistel permutation 1for a pseudo-random function f is defined as (L, R) → (R,L ⊕ f (R)), where L and R are the left and right part of the input and ⊕ denotes bitwise XOR or, in this paper, any other group operation on {0,1}n. The only non-trivial step of the security proof consists of proving that the cascade of r Feistel permutations with independent uniform random functions {0,1}n → {0,1}n, denoted Ψ2nr is indistinguishable from a uniform random permutation {0,1}2n → {0,1}2n by any computationally unbounded adaptive distinguisher making at most O(2cn) combined chosen plaintext/ciphertext queries for any c < α, where a is a security parameter. Luby and Rackoff proved α = 1/2 for r = 4. A natural problem, proposed by Pieprzyk is to improve on α for larger r. The best known result, α = 3/4 for r = 6, is due to Patarin. In this paper we prove a = 1 -O(1/r), i.e., the trivial upper bound α = 1 can be approached. The proof uses some new techniques that can be of independent interest. },
author = {Maurer, Ueli M and Krzysztof Pietrzak},
pages = {544 -- 561},
publisher = {Springer},
title = {{The security of many round Luby Rackoff pseudo random permutations}},
doi = {10.1007/3-540-39200-9_34},
volume = {2656},
year = {2003},
}
@inbook{3458,
author = {Peter Jonas and Unsicker, Klaus},
booktitle = {Lehrbuch Vorklinik},
editor = {Schmidt, R. F.},
pages = {3 -- 26},
publisher = {Deutscher Ärzte Verlag},
title = {{Molekulare und zelluläre Grundlagen des Nervensystems.}},
volume = {B},
year = {2003},
}
@article{3526,
abstract = {Neurons can produce action potentials with high temporal precision(1). A fundamental issue is whether, and how, this capability is used in information processing. According to the `cell assembly' hypothesis, transient synchrony of anatomically distributed groups of neurons underlies processing of both external sensory input and internal cognitive mechanisms(2-4). Accordingly, neuron populations should be arranged into groups whose synchrony exceeds that predicted by common modulation by sensory input. Here we find that the spike times of hippocampal pyramidal cells can be predicted more accurately by using the spike times of simultaneously recorded neurons in addition to the animals location in space. This improvement remained when the spatial prediction was refined with a spatially dependent theta phase modulation(5-8). The time window in which spike times are best predicted from simultaneous peer activity is 10-30 ms, suggesting that cell assemblies are synchronized at this timescale. Because this temporal window matches the membrane time constant of pyramidal neurons(9), the period of the hippocampal gamma oscillation(10) and the time window for synaptic plasticity(11), we propose that cooperative activity at this timescale is optimal for information transmission and storage in cortical circuits.},
author = {Harris, Kenneth D and Jozsef Csicsvari and Hirase, Hajima and Dragoi, George and Buzsáki, György},
journal = {Nature},
number = {6948},
pages = {552 -- 556},
publisher = {Nature Publishing Group},
title = {{Organization of cell assemblies in the hippocampus}},
doi = {0.1038/nature01834},
volume = {424},
year = {2003},
}
@article{3528,
abstract = {Gamma frequency oscillations (30-100 Hz) have been suggested to underlie various cognitive and motor functions. Here, we examine the generation of gamma oscillation currents in the hippocampus, using two-dimensional, 96-site silicon probes. Two gamma generators were identified, one in the dentate gyrus and another in the CA3-CA1 regions. The coupling strength between the two oscillators varied during both theta and nontheta states. Both pyramidal cells and interneurons were phase-locked to gamma waves. Anatomical connectivity, rather than physical distance, determined the coupling strength of the oscillating neurons. CA3 pyramidal neurons discharged CA3 and CA1 interneurons at latencies indicative of monosynaptic connections. Intrahippocampal gamma oscillation emerges in the CA3 recurrent system, which entrains the CA1 region via its interneurons.},
author = {Jozsef Csicsvari and Jamieson, Brian G and Wise, Kensall D and Buzsáki, György},
journal = {Neuron},
number = {2},
pages = {311 -- 322},
publisher = {Elsevier},
title = {{Mechanisms of gamma oscillations in the hippocampus of the behaving rat}},
doi = {10.1016/S0896-6273(02)01169-8},
volume = {37},
year = {2003},
}
@article{3529,
abstract = {Parallel recording of neuronal activity in the behaving animal is a prerequisite for our understanding of neuronal representation and storage of information. Here we describe the development of micro-machined silicon microelectrode arrays for unit and local field recordings. The two-dimensional probes with 96 or 64 recording sites provided high-density recording of unit and field activity with minimal tissue displacement or damage. The on-chip active circuit eliminated movement and other artifacts and greatly reduced the weight of the headgear. The precise geometry of the recording tips allowed for the estimation of the spatial location of the recorded neurons and for high-resolution estimation of extracellular current source density. Action potentials could be simultaneously recorded from the soma and dendrites of the same neurons. Silicon technology is a promising approach for high-density, high-resolution sampling of neuronal activity in both basic research and prosthetic devices.},
author = {Jozsef Csicsvari and Henze, Darrell A and Jamieson, Brian G and Harris, Kenneth D and Sirota, Anton M and Bartho, Peter and Wise, Kensall D and Buzsáki, György},
journal = {Journal of Neurophysiology},
number = {2},
pages = {1314 -- 1323},
publisher = {American Physiological Society},
title = {{Massively parallel recording of unit and local field potentials with silicon-based electrodes}},
doi = {10.1152/jn.00116.2003},
volume = {90},
year = {2003},
}
@article{3536,
abstract = {Genetic engineering of the mouse brain allows investigators to address novel hypotheses in vivo. Because of the paucity of information on the network patterns of the mouse hippocampus, we investigated the electrical patterns in the behaving animal using multisite silicon probes and wire tetrodes. Theta (6-9 Hz) and gamma (40-100 Hz) oscillations were present during exploration and rapid eye movement sleep. Gamma power and theta power were comodulated and gamma power varied as a function of the theta cycle. Pyramidal cells and putative interneurons were phase-locked to theta oscillations. During immobility, consummatory behaviors and slow-wave sleep, sharp waves were present in cornu ammonis region CA1 of the hippocampus stratum radiatum associated with 140-200-Hz “ripples” in the pyramidal cell layer and population burst of CA1 neurons. In the hilus, large-amplitude “dentate spikes” occurred in association with increased discharge of hilar neurons. The amplitude of field patterns was larger in the mouse than in the rat, likely reflecting the higher neuron density in a smaller brain. We suggest that the main hippocampal network patterns are mediated by similar pathways and mechanisms in mouse and rat. },
author = {Buzsáki, György and Buhl, Derek L and Harris, Kenneth D and Jozsef Csicsvari and Czéh, Boldizsár and Morozov, Alexei},
journal = {Neuroscience},
number = {1},
pages = {201 -- 211},
publisher = {Elsevier},
title = {{Hippocampal network patterns of activity in the mouse}},
doi = {10.1016/S0306-4522(02)00669-3},
volume = {116},
year = {2003},
}
@article{3543,
abstract = {Both neocortical and hippocampal networks organize the firing patterns of their neurons by prominent oscillations during sleep, but the functional role of these rhythms is not well understood. Here, we show a robust correlation of neuronal discharges between the somatosensory cortex and hippocampus on both slow and fine time scales in the mouse and rat. Neuronal bursts in deep cortical layers, associated with sleep spindles and delta waves/slow rhythm, effectively triggered hippocampal discharges related to fast (ripple) oscillations. We hypothesize that oscillation-mediated temporal links coordinate specific information transfer between neocortical and hippocampal cell assemblies. Such a neocortical-hippocampal interplay may be important for memory consolidation.},
author = {Sirota, Anton M and Jozsef Csicsvari and Buhl, Derek L and Buzsáki, György},
journal = {PNAS},
number = {4},
pages = {2065 -- 2069},
publisher = {National Academy of Sciences},
title = {{Communication between neocortex and hippocampus during sleep in rodents}},
doi = {10.1073/pnas.0437938100},
volume = {100},
year = {2003},
}
@inproceedings{3556,
abstract = {We define the Morse-Smale complex of a Morse function over a 3-manifold as the overlay of the descending and as- cending manifolds of all critical points. In the generic case, its 3-dimensional cells are shaped like crystals and are sepa- rated by quadrangular faces. In this paper, we give a combi- natorial algorithm for constructing such complexes for piece- wise linear data.},
author = {Herbert Edelsbrunner and Harer, John and Natarajan, Vijay and Pascucci, Valerio},
pages = {361 -- 370},
publisher = {ACM},
title = {{Morse-Smale complexes for piecewise linear 3-manifolds}},
doi = {10.1145/777792.777846},
year = {2003},
}
@inbook{3573,
abstract = {Given a finite point set in R, the surface reconstruction problem asks for a surface that passes through many but not necessarily all points. We describe an unambigu- ous definition of such a surface in geometric and topological terms, and sketch a fast algorithm for constructing it. Our solution overcomes past limitations to special point distributions and heuristic design decisions.},
author = {Herbert Edelsbrunner},
booktitle = {Discrete & Computational Geometry},
pages = {379 -- 404},
publisher = {Springer},
title = {{Surface reconstruction by wrapping finite sets in space}},
doi = {10.1007/978-3-642-55566-4_17},
year = {2003},
}
@article{3584,
abstract = {We develop fast algorithms for computing the linking number of a simplicial complex within a filtration.We give experimental results in applying our work toward the detection of non-trivial tangling in biomolecules, modeled as alpha complexes.},
author = {Edelsbrunner, Herbert and Zomorodian, Afra},
journal = {Homology, Homotopy and Applications},
number = {2},
pages = {19 -- 37},
publisher = {International Press},
title = {{Computing linking numbers of a filtration}},
volume = {5},
year = {2003},
}
@article{3593,
abstract = {Temporal logics such as Computation Tree Logic (CTL) and Linear Temporal Logic (LTL) have become popular for specifying temporal properties over a wide variety of planning and verification problems. In this paper we work towards building a generalized framework for automated reasoning based on temporal logics. We present a powerful extension of CTL with first-order quantification over the set of reachable states for reasoning about extremal properties of weighted labeled transition systems in general. The proposed logic, which we call Weighted Quantified Computation Tree Logic (WQCTL), captures the essential elements common to the domain of planning and verification problems and can thereby be used as an effective specification language in both domains. We show that in spite of the rich, expressive power of the logic, we are able to evaluate WQCTL formulas in time polynomial in the size of the state space times the length of the formula. Wepresent experimental results on the WQCTL verifier.},
author = {Krishnendu Chatterjee and Dasgupta, Pallab and Chakrabarti, Partha P},
journal = {Journal of Automated Reasoning},
number = {2},
pages = {205 -- 232},
publisher = {Springer},
title = {{A branching time temporal framework for quantitative reasoning}},
doi = {10.1023/A:1023217515688},
volume = {30},
year = {2003},
}
@article{3618,
abstract = {There are several analyses in evolutionary ecology which assume that a family of offspring has come from only two parents. Here, we present a simple test for detecting when a batch involves two or more subfamilies. It is based on the fact that the mixing of families generates associations amongst unlinked marker loci. We also present simulations illustrating the power of our method for varying numbers of loci, alleles per locus and genotyped individuals.},
author = {Vines, Timothy H and Nicholas Barton},
journal = {Molecular Ecology},
number = {7},
pages = {1999 -- 2002},
publisher = {Wiley-Blackwell},
title = {{A new approach to detecting mixed families}},
doi = {10.1046/j.1365-294X.2003.01867.x},
volume = {12},
year = {2003},
}
@article{3619,
abstract = {What is the chance that some part of a stretch of genome will survive? In a population of constant size, and with no selection, the probability of survival of some part of a stretch of map length y<1 approaches View the MathML source for View the MathML source. Thus, the whole genome is certain to be lost, but the rate of loss is extremely slow. This solution extends to give the whole distribution of surviving block sizes as a function of time. We show that the expected number of blocks at time t is 1+yt and give expressions for the moments of the number of blocks and the total amount of genome that survives for a given time. The solution is based on a branching process and assumes complete interference between crossovers, so that each descendant carries only a single block of ancestral material. We consider cases where most individuals carry multiple blocks, either because there are multiple crossovers in a long genetic map, or because enough time has passed that most individuals in the population are related to each other. For species such as ours, which have a long genetic map, the genome of any individual which leaves descendants (∼80% of the population for a Poisson offspring number with mean two) is likely to persist for an extremely long time, in the form of a few short blocks of genome.},
author = {Baird, Stuart J and Nicholas Barton and Etheridge, Alison M},
journal = {Theoretical Population Biology},
number = {4},
pages = {451 -- 471},
publisher = {Academic Press},
title = {{The distribution of surviving blocks of an ancestral genome}},
doi = {10.1016/S0040-5809(03)00098-4},
volume = {64},
year = {2003},
}
@article{3620,
abstract = {Stable hybrid zones in which ecologically divergent taxa give rise to a range of recombinants are natural laboratories in which the genetic basis of adaptation and reproductive isolation can be unraveled. One such hybrid zone is formed by the fire-bellied toads Bombina bombina and B. variegata (Anura: Discoglossidae). Adaptations to permanent and ephemeral breeding habitats, respectively, have shaped numerous phenotypic differences between the taxa. All of these are, in principle, candidates for a genetic dissection via QTL mapping. We present here a linkage map of 28 codominant and 10 dominant markers in the Bombina genome. In an F2 cross, markers that were mainly microsatellites, SSCPs or allozymes were mapped to 20 linkage groups. Among the 40 isolated CA microsatellites, we noted a preponderance of compound and frequently interleaved CA-TA repeats as well as a striking polarity at the 5′ end of the repeats.},
author = {Nürnberger, Beate and Hofman, Sebastian and Förg-Brey, Bqruni and Praetzel, Gabriele and Maclean, Alan W and Szymura, Jacek M and Abbott, Catherine M and Nicholas Barton},
journal = {Heredity},
number = {2},
pages = {136 -- 142},
publisher = {Nature Publishing Group},
title = {{A linkage map for the hybridising toads Bombina bombina and B. variegata (Anura: Discoglossidae)}},
doi = {10.1038/sj.hdy.6800291},
volume = {91},
year = {2003},
}
@phdthesis{3678,
author = {Christoph Lampert},
booktitle = {Bonner Mathematische Schriften},
pages = {1 -- 165},
publisher = {Universität Bonn, Fachbibliothek Mathematik},
title = {{The Neumann operator in strictly pseudoconvex domains with weighted Bergman metric }},
volume = {356},
year = {2003},
}
@article{3725,
abstract = {The combination of high-resolution atomic force microscopy (AFM) imaging and single-molecule force-spectroscopy was employed to unfold single bacteriorhodopsins (BR) from native purple membrane patches at various physiologically relevant temperatures. The unfolding spectra reveal detailed insight into the stability of individual structural elements of BR against mechanical unfolding. Intermittent states in the unfolding process are associated with the stepwise unfolding of alpha-helices, whereas other states are associated with the unfolding of polypeptide loops connecting the alpha-helices. It was found that the unfolding forces of the secondary structures considerably decreased upon increasing the temperature from 8 to 52°C. Associated with this effect, the probability of individual unfolding pathways of BR was significantly influenced by the temperature. At lower temperatures, transmembrane alpha-helices and extracellular polypeptide loops exhibited sufficient stability to individually establish potential barriers against unfolding, whereas they predominantly unfolded collectively at elevated temperatures. This suggests that increasing the temperature decreases the mechanical stability of secondary structural elements and changes molecular interactions between secondary structures, thereby forcing them to act as grouped structures.},
author = {Harald Janovjak and Kessler, Max and Oesterhelt, Dieter and Gaub, Hermann and Mueller, Daniel J},
journal = {EMBO Journal},
number = {19},
pages = {5220 -- 5229},
publisher = {Wiley-Blackwell},
title = {{Unfolding pathways of native bacteriorhodopsin depend on temperature}},
doi = {10.1093/emboj/cdg509},
volume = {22},
year = {2003},
}
@article{3752,
abstract = {We use the lac operon in Escherichia coli as a prototype system to illustrate the current state, applicability, and limitations of modeling the dynamics of cellular networks. We integrate three different levels of description (molecular, cellular, and that of cell population) into a single model, which seems to capture many experimental aspects of the system.},
author = {Vilar,Jose M and Calin Guet and Leibler, Stanislas},
journal = {Journal of Cell Biology},
number = {3},
pages = {471 -- 476},
publisher = {Rockefeller University Press},
title = {{Modeling network dynamics: the lac operon, a case study}},
doi = {10.1083/jcb.200301125},
volume = {161},
year = {2003},
}
@article{3804,
abstract = {Kv3 channels are thought to be essential for the fast-spiking (FS) phenotype in GABAergic interneurons, but how these channels confer the ability to generate action potentials (APs) at high frequency is unknown. To address this question, we developed a fast dynamic-clamp system (approximately 50 kHz) that allowed us to add a Kv3 model conductance to CA1 oriens alveus (OA) interneurons in hippocampal slices. Selective pharmacological block of Kv3 channels by 0.3 mm 4-aminopyridine or 1 mm tetraethylammonium ions led to a marked broadening of APs during trains of short stimuli and a reduction in AP frequency during 1 sec stimuli. The addition of artificial Kv3 conductance restored the original AP pattern. Subtraction of Kv3 conductance by dynamic clamp mimicked the effects of the blockers. Application of artificial Kv3 conductance also led to FS in OA interneurons after complete K+ channel block and even induced FS in hippocampal pyramidal neurons in the absence of blockers. Adding artificial Kv3 conductance with altered deactivation kinetics revealed a nonmonotonic relationship between mean AP frequency and deactivation rate, with a maximum slightly above the original value. Insertion of artificial Kv3 conductance with either lowered activation threshold or inactivation also led to a reduction in the mean AP frequency. However, the mechanisms were distinct. Shifting the activation threshold induced adaptation, whereas adding inactivation caused frequency-dependent AP broadening. In conclusion, Kv3 channels are necessary for the FS phenotype of OA interneurons, and several of their gating properties appear to be optimized for high-frequency repetitive activity.},
author = {Lien, Cheng-Chang and Peter Jonas},
journal = {Journal of Neuroscience},
number = {6},
pages = {2058 -- 68},
publisher = {Society for Neuroscience},
title = {{Kv3 potassium conductance is necessary and kinetically optimized for high-frequency action potential generation in hippocampal interneurons}},
volume = {23},
year = {2003},
}
@article{3806,
abstract = {To probe exocytosis at a cortical glutamatergic synapse, we made capacitance measurements in whole-cell recorded hippocampal mossy fiber terminals. Evaluation of different methods by using a morphology-based equivalent electrical model revealed that quantitative capacitance measurements are possible in this presynaptic structure. Voltage pulses leading to presynaptic Ca2+ inflow evoked large capacitance signals that showed saturation with increasing pulse duration. The mean peak capacitance increase was 100 fF, corresponding to a pool of approximately 1,400 releasable vesicles. Thus hippocampal mossy fiber synapses have a vesicular "maxipool." Large pool size and rapid vesicle recycling may underlie the uniquely large extent of activity-dependent plasticity in this synapse.},
author = {Hallermann, Stefan and Pawlu, Christian and Peter Jonas and Heckmann, Manfred},
journal = {PNAS},
number = {15},
pages = {8975 -- 80},
publisher = {National Academy of Sciences},
title = {{A large pool of releasable vesicles in a cortical glutamatergic synapse}},
doi = {10.1073/pnas.1432836100},
volume = {100},
year = {2003},
}
@inproceedings{3897,
abstract = {Many verification, planning, and control problems can be modeled as games played on state-transition graphs by one or two players whose conflicting goals are to form a path in the graph. The focus here is on simple stochastic parity games, that is, two-player games with turn-based probabilistic transitions and omega-regular objectives formalized as parity (Rabin chain) winning conditions. An efficient translation from simple stochastic parity games to nonstochastic parity games is given. As many algorithms are known for solving the latter, the translation yields efficient algorithms for computing the states of a simple stochastic parity game from which a player can win with probability 1. An important special case of simple stochastic parity games are the Markov decision processes with Buchi objectives. For this special case a first provably subquadratic algorithm is given for computing the states from which the single player has a strategy to achieve a Buchi objective with probability 1. For game graphs with m edges the algorithm works in time O(mrootm). Interestingly, a similar technique sheds light on the question of the computational complexity of solving simple Buchi games and yields the first provably subquadratic algorithm, with a running time of O(n(2)/log n) for game graphs with n vertices and O(n) edges.},
author = {Krishnendu Chatterjee and Jurdziński, Marcin and Thomas Henzinger},
pages = {100 -- 113},
publisher = {Springer},
title = {{Simple stochastic parity games}},
doi = {10.1007/978-3-540-45220-1_11},
volume = {2803},
year = {2003},
}