@article{213,
abstract = {For any integers d,n ≥2, let X ⊂ Pn be a non‐singular hypersurface of degree d that is defined over the rational numbers. The main result in this paper is a proof that the number of rational points on X which have height at most B is O(Bn − 1 + ɛ), for any ɛ > 0. The implied constant in this estimate depends at most upon d, ɛ and n. 2000 Mathematics Subject Classification 11D45 (primary), 11G35, 14G05 (secondary).},
author = {Timothy Browning and Heath-Brown, Roger and Starr, Jason M},
journal = {Proceedings of the London Mathematical Society},
number = {2},
pages = {273 -- 303},
publisher = {John Wiley and Sons Ltd},
title = {{The density of rational points on non-singular hypersurfaces, II}},
doi = {https://doi.org/10.1112/S0024611506015784},
volume = {93},
year = {2006},
}
@article{2134,
abstract = {Predissociation of the N+2 C 2Σ+u(v') vibrational levels with v' ≥ 3 was observed via dispersed C 2Σ+u → X 2Σ+g fluorescence in the spectral range of 165–208 nm after resonant 1s−1π*(vr) excitation of N2 and its subsequent autoionization into the N+2 C state. This range is dominated by lines in atomic nitrogen, by overlapped C 2Σ+u(v') → X 2Σ+g(v'') vibrational band sequences with Δv = const and broad unresolved band systems (D, (2))2Πg(v') → A2Πu(v'') in the N+2 molecular ion. With very high fluorescence resolution of about 0.1 nm FWHM individual C 2Σ+u(v') → X 2Σ+g(v'') vibrational bands have been resolved. Calculation of the observed fluorescence spectra by taking into account predissociation and molecular rotation describes well the shape of both individual vibrational bands C 2Σ+u(v') → X 2Σ+g(v'') and the whole band system.},
author = {Ehresmann, Arno and Werner, Lutz and Klumpp, Stefan and Demekhin, Ph V and Mikhail Lemeshko and Sukhorukov, V. L and Schartner, Karl H and Schmoranzer, Hans P},
journal = {Journal of Physics B: Atomic, Molecular and Optical Physics},
number = {6},
pages = {L119 -- L126},
publisher = {IOP Publishing Ltd.},
title = {{Predissociation of the N+2(C 2Σ+u) state observed via C 2Σ+u → X 2Σ+g fluorescence after resonant 1s−1π* excitation of N2 molecule}},
doi = {10.1088/0953-4075/39/6/L03},
volume = {39},
year = {2006},
}
@article{2142,
abstract = {Fluorescence from fragments formed after the de-excitation of the N*2(1s−1π*) resonance has been measured in the spectral range of 135–190 nm. This range is dominated by lines in atomic nitrogen and lines formed by overlapping C2Σ+u(v') → X2Σ+g(v'') bands with Δv = const in the N+2 molecular ion which result from the spectator Auger decays of the N*2(1s−1π*(vr)) resonances. Ab initio calculations of the corresponding potential curves and transition probabilities showed that the observed irregular intensity dependence of the C2Σ+u(v') → X2Σ+g(v'')(Δv = const) fluorescence lines on the vibrational quantum number vr is due to transitions between vibrational levels during the reaction N2(v0 = 0)→ N*2(1s−1π*(vr)) Longrightarrow C2Σ+u(v') → X2Σ+g(v'').},
author = {Ehresmann, Arno and Werner, Lutz and Klumpp, Stefan and Lucht, S and Schmoranzer, Hans P and Mickat, Sascha and Schill, Rüdiger H and Schartner, Karl H and Demekhin, Philipp and Mikhail Lemeshko and Sukhorukov, Victor L},
journal = {Journal of Physics B: Atomic, Molecular and Optical Physics},
number = {2},
pages = {283 -- 304},
publisher = {IOP Publishing Ltd.},
title = {{Studying the N+2(C2Σ+u → X2Σ+g) fluorescence excited via the 1s−1π* resonance}},
doi = {10.1088/0953-4075/39/2/006},
volume = {39},
year = {2006},
}
@article{2144,
abstract = {Temperature dependent preedge and extended x-ray absorption fine structure measurements at the Zr K edge for the perovskite-type zirconates Pb Zr0.515 Ti0.485 O3 (PZT), PbZr O3 (PZ), and BaZr O3 are performed. To carry out a more accurate study of the weak reconstruction of the local atomic structure we employed a combination of two techniques: (i) analysis of the preedge fine structure, and (ii) analysis of the Fourier transform of the difference between χ (k) functions obtained at different temperatures. A detailed investigation of local atomic structure in the cubic phase for all the crystals is also performed. It is shown that neither the displacive nor the order-disorder model can describe correctly the changes of local atomic structure during phase transitions in PZ and PZT. A spherical model describing the local atomic structure of perovskite-type crystals suffering structural phase transitions is proposed.},
author = {Vedrinskiǐ, Rostislav V and Nazarenko, Elena S and Mikhail Lemeshko and Nassif, Vivian M and Proux, Olivier and Novakovich, Alexander A and Joly, Yves},
journal = {Physical Review B - Condensed Matter and Materials Physics},
number = {13},
publisher = {American Physical Society},
title = {{Temperature dependent XAFS studies of local atomic structure of the perovskite-type zirconates}},
doi = {10.1103/PhysRevB.73.134109},
volume = {73},
year = {2006},
}
@article{215,
abstract = {For any n≥3, let F ∈ Z[X0,...,Xn ] be a form of degree d *≥5 that defines a non-singular hypersurface X ⊂ Pn . The main result in this paper is a proof of the fact that the number N (F ; B) of Q-rational points on X which have height at most B satisfiesN (F ; B) = Od,ε,n (Bn −1+ε ), for any ε > 0. The implied constant in this estimate depends at most upon d, ε and n. New estimates are also obtained for the number of representations of a positive integer as the sum of three dth powers, and for the paucity of integer solutions to equal sums of like polynomials.*},
author = {Timothy Browning and Heath-Brown, Roger},
journal = {Bulletin of the London Mathematical Society},
number = {3},
pages = {401 -- 410},
publisher = {Wiley-Blackwell},
title = {{The density of rational points on non-singular hypersurfaces, I}},
doi = {10.1112/S0024609305018412},
volume = {38},
year = {2006},
}
@article{216,
abstract = {For any N ≥ 2, let Z ⊂ ℙN be a geometrically integral algebraic variety of degree d. This article is concerned with the number Nz(B) of ℚ-rational points on Z which have height at most B. For any ε > 0, we establish the estimate NZ(B) = O d,ε,N(Bdim Z+ε), provided that d ≥ 6. As indicated, the implied constant depends at most on d, ε, and N.},
author = {Timothy Browning and Heath-Brown, Roger and Salberger, Per},
journal = {Duke Mathematical Journal},
number = {3},
pages = {545 -- 578},
publisher = {Unknown},
title = {{Counting rational points on algebraic varieties}},
doi = {10.1215/S0012-7094-06-13236-2},
volume = {132},
year = {2006},
}
@article{218,
abstract = {This paper is concerned with the average order of certain arithmetic functions, as they range over the values taken by binary forms.},
author = {de la Bretèche, Régis and Timothy Browning},
journal = {Acta Arithmetica},
number = {3},
pages = {291 -- 304},
publisher = {Instytut Matematyczny},
title = {{Sums of arithmetic functions over values of binary forms}},
doi = {10.4064/aa125-3-6},
volume = {125},
year = {2006},
}
@inproceedings{7326,
abstract = {Often the properties of a single cell are considered as representative for a complete polymer electrolyte fuel cell stack or even a fuel cell system. In some cases this comes close, however, in many real cases differences on several scales become important. Cell interaction phenomena in fuel cell stacks that arise from inequalities between adjacent cells are investigated in detail experimentally. For that, a specialized 2-cell stack with advanced localized diagnostics was developed. The results show that inequalities propagate by electrical coupling, inhomogeneous cell polarization and inducing in-plane current in the common bipolar plate. The effects of the different loss-mechanisms are analyzed and quantified. },
author = {Büchi, Felix N. and Freunberger, Stefan Alexander and Santis, Marco},
booktitle = {ECS Transactions},
location = {Cancun, Mexico},
number = {1},
pages = {963--968},
publisher = {ECS},
title = {{What is learned beyond the scale of single cells?}},
doi = {10.1149/1.2356215},
volume = {3},
year = {2006},
}
@article{7327,
abstract = {Propagation of performance changes to adjacent cells in polymer electrolyte fuel cell stacks is studied by means of voltage monitoring and local current density measurements in peripheral cells of the stack. A technical fuel cell stack has been modified by implementing two independent reactant and coolant supplies in order to deliberately change the performance of one cell (anomalous cell) and study the coupling phenomena to adjacent cells (coupling cells), while keeping the working conditions of the later cell-group unaltered.
Two anomalies are studied: (i) air starvation and (ii) thermal anomaly, in a single anomalous cell in the stack and their coupling to adjacent cells. The results have shown that anomalies inducing considerable changes in the local current density of the anomalous cell (such as air starvation) propagate to adjacent cells affecting their performance. The propagation of local current density changes takes place via the common bipolar plate due to its finite thickness and in-plane conductivity. Consequently, anomalies which do not strongly influence the local current density distribution (such as a thermal anomaly under the studied working conditions) do not propagate to adjacent cells.},
author = {Santis, Marco and Freunberger, Stefan Alexander and Papra, Matthias and Wokaun, Alexander and Büchi, Felix N.},
issn = {0378-7753},
journal = {Journal of Power Sources},
number = {2},
pages = {1076--1083},
publisher = {Elsevier},
title = {{Experimental investigation of coupling phenomena in polymer electrolyte fuel cell stacks}},
doi = {10.1016/j.jpowsour.2006.06.007},
volume = {161},
year = {2006},
}
@article{7328,
abstract = {An experimental technique for measuring the current density distribution with a resolution smaller than the channel/rib scale of the flow field in polymer electrolyte fuel cells (PEFCs) is presented. The electron conductors in a plane perpendicular to the channel direction are considered as two-dimensional resistors. Hence, the current density is obtained from the solution of Laplace's equation with the potentials at current collector and reaction layer as boundary conditions. Using ohmic drop for calculating the local current, detailed knowledge of all resistances involved is of prime importance. In particular, the contact resistance between the gas diffusion layer (GDL) and flow field rib, as well as GDL bulk conductivity, are strongly dependent on clamping pressure. They represent a substantial amount of the total ohmic drop and therefore require careful consideration. The detailed experimental setup as well as the concise procedure for quantitative data evaluation is described. Finally, the method is applied successfully to a cell operated on pure oxygen and air up to high current densities. The results show that electrical and ionic resistances seem to govern the current distribution at low current regimes, whereas mass transport limitations locally hamper the current production at high loads.},
author = {Freunberger, Stefan Alexander and Reum, Mathias and Evertz, Jörg and Wokaun, Alexander and Büchi, Felix N.},
issn = {0013-4651},
journal = {Journal of The Electrochemical Society},
number = {11},
publisher = {The Electrochemical Society},
title = {{Measuring the current distribution in PEFCs with sub-millimeter resolution}},
doi = {10.1149/1.2345591},
volume = {153},
year = {2006},
}
@article{7329,
abstract = {A novel measurement principle for measuring the current distribution in polymer electrolyte fuel cells (PEFCs) is introduced. It allows, in contrast to all other known techniques, for the first time for a resolution smaller than the channel/rib scale of the flow field in PEFCs. The current density is obtained by considering the electron conductors in the cell as a two-dimensional resistor with the voltage drop caused by the current. The method was applied to a cell operated on oxygen up to high current densities. The results show that the ohmic resistances govern the current distribution in the low current regime, whereas mass transport limitations hamper the current production under the land at high loads.},
author = {Freunberger, Stefan Alexander and Reum, Mathias and Wokaun, Alexander and Büchi, Felix N.},
issn = {1388-2481},
journal = {Electrochemistry Communications},
number = {9},
pages = {1435--1438},
publisher = {Elsevier},
title = {{Expanding current distribution measurement in PEFCs to sub-millimeter resolution}},
doi = {10.1016/j.elecom.2006.05.032},
volume = {8},
year = {2006},
}
@article{7330,
abstract = {Polymer electrolyte fuel cells (PE fuel cells) working with air at low stoichiometries (<2.0) and standard electrochemical components show a high degree of inhomogeneity in the current density distribution over the active area. An inhomogeneous current density distribution leads to a non-uniform utilization of the active area, which could negatively affect the time of life of the cells. Furthermore, it is also believed to lower cell performance. In this work, the homogenization of the current density, realized by means of tailored cathodes with along-the-air-channel redistributed catalyst loadings, is investigated. The air stoichiometry range for which a homogenization of the current density is achieved depends upon the gradient with which the catalyst is redistributed along the air channel. A gentle increasing catalyst loading profile homogenizes the current density at relatively higher air stoichiometries, while a steeper profile is suited better for lower air stoichiometries. The results show that a homogenization of the current density by means of redistributed catalyst loading has negative effects on cell performance. Model calculations corroborate the experimental findings on homogenization of the current density and deliver an explanation for the decrease in cell performance.},
author = {Santis, M. and Freunberger, Stefan Alexander and Reiner, A. and Büchi, F.N.},
issn = {0013-4686},
journal = {Electrochimica Acta},
number = {25},
pages = {5383--5393},
publisher = {Elsevier},
title = {{Homogenization of the current density in polymer electrolyte fuel cells by in-plane cathode catalyst gradients}},
doi = {10.1016/j.electacta.2006.02.008},
volume = {51},
year = {2006},
}
@article{7331,
abstract = {A previously developed mathematical model for water management and current density distribution in a polymer electrolyte fuel cell (PEFCs) is employed to investigate the effects of cooling strategies on cell performance. The model describes a two-dimensional slice through the cell along the channels and through the entire cell sandwich including the coolant channels and the bipolar plate. Arbitrary flow arrangements of fuel, oxidant, and coolant stream directions can be described. Due to the serious impact of temperature on all processes in the PEFC, both the relative direction of the coolant stream to the gas streams and its mass flow turns out to significantly affect the cell performance. Besides influencing the electrochemical reaction and all kinds of mass transfer temperature, variations predominantly alter the local membrane hydration distribution and subseqently its conductivity.},
author = {Freunberger, Stefan Alexander and Wokaun, Alexander and Büchi, Felix N.},
issn = {0013-4651},
journal = {Journal of The Electrochemical Society},
number = {5},
publisher = {The Electrochemical Society},
title = {{In-plane effects in large-scale PEFCs: II. The influence of cooling strategy on cell performance}},
doi = {10.1149/1.2185282},
volume = {153},
year = {2006},
}
@article{7332,
abstract = {A quasi-two-dimensional, along-the-channel mass and heat-transfer model for a proton exchange membrane fuel cell (PEFC) is described and validated against experimental current distribution data. The model is formulated in a dimensional manner, i.e., local transport phenomena are treated one-dimensional in through-plane direction and coupled in-plane by convective transport in the gas and coolant channels. Thus, a two-dimensional slice running through the repetitive unit of a cell from the anode channel via membrane-electrode assembly (MEA) and cathode channel to the coolant channel and from inlet to outlet is modeled. The aim of the work is to elucidate the influence of operating conditions such as feed gas humidities and stoichiometric ratios on the along-the-channel current density distribution and to identify the distinct underlying voltage loss mechanisms. Furthermore, a complicated technical flow field is modeled by a combination of co- and counterflow subdomains and compared with experimental current densities.},
author = {Freunberger, Stefan Alexander and Santis, Marco and Schneider, Ingo A. and Wokaun, Alexander and Büchi, Felix N.},
issn = {0013-4651},
journal = {Journal of The Electrochemical Society},
number = {2},
publisher = {The Electrochemical Society},
title = {{In-plane effects in large-scale PEMFCs}},
doi = {10.1149/1.2150150},
volume = {153},
year = {2006},
}
@unpublished{573,
abstract = {Mitchison and Jozsa recently suggested that the "chained-Zeno" counterfactual computation protocol recently proposed by Hosten et al. is counterfactual for only one output of the computer. This claim was based on the existing abstract algebraic definition of counterfactual computation, and indeed according to this definition, their argument is correct. However, a more general definition (physically adequate) for counterfactual computation is implicitly assumed by Hosten et. al. Here we explain in detail why the protocol is counterfactual and how the "history tracking" method of the existing description inadequately represents the physics underlying the protocol. Consequently, we propose a modified definition of counterfactual computation. Finally, we comment on one of the most interesting aspects of the error-correcting protocol. },
author = {Hosten, Onur and Rakher, Matthew and Barreiro, Julio and Peters, Nicholas and Kwiat, Paul},
pages = {12},
publisher = {ArXiv},
title = {{Counterfactual computation revisited}},
year = {2006},
}
@unpublished{574,
abstract = {Vaidman, in a recent article adopts the method of 'quantum weak measurements in pre- and postselected ensembles' to ascertain whether or not the chained-Zeno counterfactual computation scheme proposed by Hosten et al. is counterfactual; which has been the topic of a debate on the definition of counterfactuality. We disagree with his conclusion, which brings up some interesting aspects of quantum weak measurements and some concerns about the way they are interpreted. },
author = {Hosten, Onur and Kwiat, Paul},
pages = {2},
publisher = {ArXiv},
title = {{Weak measurements and counterfactual computation}},
year = {2006},
}
@inproceedings{577,
abstract = {Visible light photon counters (VLPCs) and solid-state photomultipliers (SSPMs) are high-efficiency single-photon detectors which have multi-photon counting capability. While both the VLPCs and the SSPMs have inferred internal quantum efficiencies above 93%, the actual measured values for both the detectors were in fact limited to less than 88%, attributed to in-coupling losses. We are currently improving this overall detection efficiency via a) custom anti-reflection coating the detectors and the in-coupling fibers, b) implementing a novel cryogenic design to reduce transmission losses and, c) using low-noise electronics to obtain a better signal-to-noise ratio.},
author = {Rangarajan, Radhika and Altepeter, Joseph B and Jeffrey, Evan R and Stoutimore, Micah J and Peters, Nicholas A and Onur Hosten and Kwiat, Paul G},
publisher = {SPIE},
title = {{High-efficiency single-photon detectors}},
doi = {10.1117/12.686117},
volume = {6372},
year = {2006},
}
@inproceedings{578,
abstract = {A source of single photons allows secure quantum key distribution, in addition, to being a critical resource for linear optics quantum computing. We describe our progress on deterministically creating single photons from spontaneous parametric downconversion, an extension of the Pittman, Jacobs and Franson scheme [Phys. Rev A, v66, 042303 (2002)]. Their idea was to conditionally prepare single photons by measuring one member of a spontaneously emitted photon pair and storing the remaining conditionally prepared photon until a predetermined time, when it would be "deterministically" released from storage. Our approach attempts to improve upon this by recycling the pump pulse in order to decrease the possibility of multiple-pair generation, while maintaining a high probability of producing a single pair. Many of the challenges we discuss are central to other quantum information technologies, including the need for low-loss optical storage, switching and detection, and fast feed-forward control.},
author = {Peters, Nicholas A and Arnold, Keith J and VanDevender, Aaron P and Jeffrey, Evan R and Rangarajan, Radhika and Onur Hosten and Barreiro, Julio T and Altepeter, Joseph B and Kwiat, Paul G},
publisher = {SPIE},
title = {{Towards a quasi-deterministic single-photon source}},
doi = {10.1117/12.684702},
volume = {6305},
year = {2006},
}
@article{579,
abstract = {The logic underlying the coherent nature of quantum information processing often deviates from intuitive reasoning, leading to surprising effects. Counterfactual computation constitutes a striking example: the potential outcome of a quantum computation can be inferred, even if the computer is not run 1. Relying on similar arguments to interaction-free measurements 2 (or quantum interrogation3), counterfactual computation is accomplished by putting the computer in a superposition of 'running' and 'not running' states, and then interfering the two histories. Conditional on the as-yet-unknown outcome of the computation, it is sometimes possible to counterfactually infer information about the solution. Here we demonstrate counterfactual computation, implementing Grover's search algorithm with an all-optical approach4. It was believed that the overall probability of such counterfactual inference is intrinsically limited1,5, so that it could not perform better on average than random guesses. However, using a novel 'chained' version of the quantum Zeno effect6, we show how to boost the counterfactual inference probability to unity, thereby beating the random guessing limit. Our methods are general and apply to any physical system, as illustrated by a discussion of trapped-ion systems. Finally, we briefly show that, in certain circumstances, counterfactual computation can eliminate errors induced by decoherence. },
author = {Onur Hosten and Rakher, Matthew T and Barreiro, Julio T and Peters, Nicholas A and Kwiat, Paul G},
journal = {Nature},
number = {7079},
pages = {949 -- 952},
publisher = {Nature Publishing Group},
title = {{Counterfactual quantum computation through quantum interrogation}},
doi = {10.1038/nature04523},
volume = {439},
year = {2006},
}
@inproceedings{583,
abstract = {Visible light photon counters (VLPCs) and solid-state photomultipliers (SSPMs) facilitate efficient single-photon detection. We are attempting to improve their efficiency, previously limited to < 88% by coupling losses, via anti-reflection coatings, better electronics and cryogenics.},
author = {Rangarajan, Radhika and Peters, Nicholas A and Onur Hosten and Altepeter, Joseph B and Jeffrey, Evan R and Kwiat, Paul G},
publisher = {IEEE},
title = {{Improved single-photon detection}},
doi = {10.1109/CLEO.2006.4628641},
year = {2006},
}
@article{6151,
author = {Salecker, Iris and Häusser, Michael and de Bono, Mario},
issn = {1469-221X},
journal = {EMBO reports},
number = {6},
pages = {585--589},
publisher = {Wiley},
title = {{On the axonal road to circuit function and behaviour: Workshop on the assembly and function of neuronal circuits}},
doi = {10.1038/sj.embor.7400713},
volume = {7},
year = {2006},
}
@article{6152,
author = {Rogers, Candida and Persson, Annelie and Cheung, Benny and de Bono, Mario},
issn = {0960-9822},
journal = {Current Biology},
number = {7},
pages = {649--659},
publisher = {Elsevier},
title = {{Behavioral motifs and neural pathways coordinating O2 responses and aggregation in C. elegans}},
doi = {10.1016/j.cub.2006.03.023},
volume = {16},
year = {2006},
}
@article{1461,
abstract = {This note proves combinatorially that the intersection pairing on the middle-dimensional compactly supported cohomology of a toric hyperkähler variety is always definite, providing a large number of non-trivial L 2 harmonic forms for toric hyperkähler metrics on these varieties. This is motivated by a result of Hitchin about the definiteness of the pairing of L 2 harmonic forms on complete hyperkähler manifolds of linear growth.},
author = {Tamas Hausel and Swartz, Edward},
journal = {Proceedings of the American Mathematical Society},
number = {8},
pages = {2403 -- 2409},
publisher = {American Mathematical Society},
title = {{Intersection forms of toric hyperkähler varieties}},
doi = {10.1090/S0002-9939-06-08248-7},
volume = {134},
year = {2006},
}
@article{1462,
abstract = {A Fourier transform technique is introduced for counting the number of solutions of holomorphic moment map equations over a finite field. This technique in turn gives information on Betti numbers of holomorphic symplectic quotients. As a consequence, simple unified proofs are obtained for formulas of Poincaré polynomials of toric hyperkähler varieties (recovering results of Bielawski-Dancer and Hausel-Sturmfels), Poincaré polynomials of Hubert schemes of points and twisted Atiyah-Drinfeld-Hitchin-Manin (ADHM) spaces of instantons on ℂ2 (recovering results of Nakajima-Yoshioka), and Poincaré polynomials of all Nakajima quiver varieties. As an application, a proof of a conjecture of Kac on the number of absolutely indecomposable representations of a quiver is announced.},
author = {Tamas Hausel},
journal = {PNAS},
number = {16},
pages = {6120 -- 6124},
publisher = {National Academy of Sciences},
title = {{Betti numbers of holomorphic symplectic quotients via arithmetic Fourier transform}},
doi = {10.1073/pnas.0601337103},
volume = {103},
year = {2006},
}
@article{1033,
abstract = {Systems of three interacting particles are notorious for their complex physical behaviour. A landmark theoretical result in few-body quantum physics is Efimov\'s prediction1,2 of a universal set of bound trimer states appearing for three identical bosons with a resonant two-body interaction. Counterintuitively, these states even exist in the absence of a corresponding two-body bound state. Since the formulation of Efimov\'s problem in the context of nuclear physics 35 years ago, it has attracted great interest in many areas of physics3-8. However, the observation of Efimov quantum states has remained an elusive goal3,5. Here we report the observation of an Efimov resonance in an ultracold gas of caesium atoms. The resonance occurs in the range of large negative two-body scattering lengths, arising from the coupling of three free atoms to an Efimov trimer. Experimentally, we observe its signature as a giant three-body recombination loss9,10 when the strength of the two-body interaction is varied. We also detect a minimum 9,11,12 in the recombination loss for positive scattering lengths, indicating destructive interference of decay pathways. Our results confirm central theoretical predictions of Efimov physics and represent a starting point with which to explore the universal properties of resonantly interacting few-body systems7. While Feshbach resonances13,14 have provided the key to control quantum-mechanical interactions on the two-body level, Efimov resonances connect ultracold matter15 to the world of few-body quantum phenomena.},
author = {Kraemer, Tobias and Mark, Michael and Waldburger, Philipp and Danzl, Johann G and Chin, Cheng and Engeser, Bastian and Lange, Adam and Pilch, Karl and Jaakkola, Antti and Nägerl, Hanns and Grimm, Rudolf},
journal = {Nature},
number = {7082},
pages = {315 -- 318},
publisher = {Nature Publishing Group},
title = {{Evidence for Efimov quantum states in an ultracold gas of caesium atoms}},
doi = {10.1038/nature04626},
volume = {440},
year = {2006},
}
@inproceedings{1034,
abstract = {Three interacting particles form a system which is well known for its complex physical behavior. A landmark theoretical result in few-body quantum physics is Efimov\'s prediction of a universal set of weakly bound trimer states appearing for three identical bosons with a resonant two-body interaction [1, 2]. Surprisingly, these states even exist in the absence of a corresponding two-body bound state and their precise nature is largely independent of the particular type of the two-body interaction potential. Efimov\'s scenario has attracted great interest in many areas of physics; an experimental test however has not been achieved. We report the observation of an Efimov resonance in an ultracold thermal gas of cesium atoms [3]. The resonance occurs in the range of large negative two-body scattering lengths and arises from the coupling of three free atoms to an Efimov trimer. We observe its signature as a giant three-body recombination loss when the strength of the two-body interaction is varied near a Feshbach resonance. This resonance develops into a continuum resonance at non-zero collision energies, and we observe a shift of the resonance position as a function of temperature. We also report on a minimum in the recombination loss for positive scattering lengths, indicating destructive interference of decay pathways. Our results confirm central theoretical predictions of Efimov physics and represent a starting point from which to explore the universal properties of resonantly interacting few-body systems.},
author = {Nägerl, Hanns and Kraemer, Tobias and Mark, Michael and Waldburger, Philipp and Danzl, Johann G and Engeser, Bastian and Lange, Adam and Pilch, Karl and Jaakkola, Antti and Chin, Cheng and Grimm, Rudolf},
pages = {269 -- 277},
publisher = {AIP},
title = {{Experimental evidence for Efimov quantum states}},
doi = {10.1063/1.2400657},
volume = {869},
year = {2006},
}
@article{903,
abstract = {Background: Carcinogenesis typically involves multiple somatic mutations in caretaker (DNA repair) and gatekeeper (tumor suppressors and oncogenes) genes. Analysis of mutation spectra of the tumor suppressor that is most commonly mutated in human cancers, p53, unexpectedly suggested that somatic evolution of the p53 gene during tumorigenesis is dominated by positive selection for gain of function. This conclusion is supported by accumulating experimental evidence of evolution of new functions of p53 in tumors. These findings prompted a genome-wide analysis of possible positive selection during tumor evolution. Methods: A comprehensive analysis of probable somatic mutations in the sequences of Expressed Sequence Tags (ESTs) from malignant tumors and normal tissues was performed in order to access the prevalence of positive selection in cancer evolution. For each EST, the numbers of synonymous and non-synonymous substitutions were calculated. In order to identify genes with a signature of positive selection in cancers, these numbers were compared to: i) expected numbers and ii) the numbers for the respective genes in the ESTs from normal tissues. Results: We identified 112 genes with a signature of positive selection in cancers, i.e., a significantly elevated ratio of non-synonymous to synonymous substitutions, in tumors as compared to 37 such genes in an approximately equal-sized EST collection from normal tissues. A substantial fraction of the tumor-specific positive-selection candidates have experimentally demonstrated or strongly predicted links to cancer. Conclusion: The results of EST analysis should be interpreted with extreme caution given the noise introduced by sequencing errors and undetected polymorphisms. Furthermore, an inherent limitation of EST analysis is that multiple mutations amenable to statistical analysis can be detected only in relatively highly expressed genes. Nevertheless, the present results suggest that positive selection might affect a substantial number of genes during tumorigenic somatic evolution.},
author = {Babenko, Vladimir N and Basu, Malay K and Fyodor Kondrashov and Rogozin, Igor B and Koonin, Eugene V},
journal = {BMC Cancer},
publisher = {BioMed Central},
title = {{Signs of positive selection of somatic mutations in human cancers detected by EST sequence analysis}},
doi = {10.1186/1471-2407-6-36},
volume = {6},
year = {2006},
}
@inbook{3722,
author = {Harald Janovjak and Mueller, Daniel J},
booktitle = {Bioanalytik},
publisher = {Spektrum Akademischer Verlag},
title = {{Rastersondenmikroskopie}},
year = {2006},
}
@article{3728,
abstract = {Mechanical unfolding of single bacteriorhodopsins from a membrane bilayer is studied using molecular dynamics simulations. The initial conformation of the lipid membrane is determined through all-atom simulations and then its coarse-grained representation is used in the studies of stretching. A Go-like model with a realistic contact map and with Lennard–Jones contact interactions is applied to model the protein–membrane system. The model qualitatively reproduces the experimentally observed differences between force-extension patterns obtained on bacteriorhodopsin at different temperatures and predicts a lack of symmetry in the choice of the terminus to pull by. It also illustrates the decisive role of the interactions of the protein with the membrane in determining the force pattern and thus the stability of transmembrane proteins.},
author = {Cieplak, Marek and Filipek, Sławomir and Harald Janovjak and Krzysko, Krystiana A},
journal = {Biochimica et Biophysica Acta (BBA) - Biomembranes},
number = {4},
pages = {537 -- 544},
publisher = {Elsevier},
title = {{Pulling single bacteriorhodopsin out of a membrane: Comparison of simulation and experiment}},
doi = {10.1016/j.bbamem.2006.03.028},
volume = {1758},
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},
}
@article{3750,
abstract = {We applied a single-cell assay to characterize how transcription dynamics affects protein expression levels of a tetracycline-inducible gene expression system. Transcriptional activity of the tetracycline promoter in response to a steady level of inducer is steady in ΔacrAB efflux mutant but pulsating in wildtype Escherichia coli cells. We found that the expression level of the green fluorescent protein is several folds higher in ΔacrAB efflux mutant than in wildtype cells.},
author = {Le,Thuc T. and Calin Guet and Cluzel,Philippe},
journal = {Protein Expression and Purification},
number = {1},
pages = {28 -- 31},
publisher = {Elsevier},
title = {{Protein expression enhancement in efflux-deleted mutant bacteria}},
volume = {48},
year = {2006},
}
@article{3755,
abstract = {A primitive example of adaptation in gene expression is the balance between the rate of synthesis and degradation of cellular RNA, which allows rapid responses to environmental signals. Here, we investigate how multidrug efflux pump systems mediate the dynamics of a simple drug-inducible system in response to a steady level of inducer. Using fluorescence correlation spectroscopy, we measured in real time within a single bacterium the transcription activity at the RNA level of the acrAB-TolC multidrug efflux pump system. When cells are exposed to constant level of anhydrotetracycline inducer and are adsorbed onto a poly-L-lysine-coated surface, we found that the acrAB-TolC promoter is steadily active. We also monitored the activity of the tet promoter to characterize the effect of this efflux system on the dynamics of drug-inducible transcription. We found that the transcriptional response of the tet promoter to a steady level of aTc rises and then falls back to its preinduction level. The rate of RNA degradation was constant throughout the transcriptional pulse, indicating that the modulation of intracellular inducer concentration alone can produce this pulsating response. Single-cell experiments together with numerical simulations suggest that such pulsating response in drug-inducible genetic systems is a property emerging from the dependence of drug-inducible transcription on multidrug efflux systems.},
author = {Le,Thuc T. and Emonet,Thierry and Harlepp, Sébastien and Calin Guet and Cluzel,Philippe},
journal = {Biophysical Journal},
number = {9},
pages = {3315 -- 3321},
publisher = {Biophysical Society},
title = {{Dynamical determinants of drug-inducible gene expression in a single bacterium}},
doi = {10.1529/biophysj.105.073353},
volume = {90},
year = {2006},
}
@inproceedings{3758,
abstract = {Control of physical simulation has become a popular topic in the field of computer graphics. Keyframe control has been applied to simulations of rigid bodies, smoke, liquid, flocks, and finite element-based elastic bodies. In this paper, we create a framework for controlling systems of interacting particles -- paying special attention to simulations of cloth and flocking behavior. We introduce a novel integrator-swapping approximation in order to apply the adjoint method to linearized implicit schemes appropriate for cloth simulation. This allows the control of cloth while avoiding computationally infeasible derivative calculations. Meanwhile, flocking control using the adjoint method is significantly more efficient than currently-used methods for constraining group behaviors, allowing the controlled simulation of greater numbers of agents in fewer optimization iterations.},
author = {Wojtan, Christopher J and Mucha, Peter and Turk, Greg},
pages = {15 -- 23},
publisher = {ACM},
title = {{Keyframe control of complex particle systems using the adjoint method}},
year = {2006},
}
@article{3767,
abstract = {Models of RNA secondary structure folding are widely used to study evolution in theory and simulation. However, systematic studies of the parameters involved are rare. In this paper, we study by simulation how RNA evolution is influenced by three different factors, namely the mutation rate, scaling of the fitness function, and distance measure. We found that for low mutation rates the qualitative evolutionary behavior is robust with respect to the scaling of the fitness function. For efficient mutation rates, which are close to the error threshold, scaling and distance measure have a strong influence on the evolutionary behavior. A global distance measure that takes sequence information additively into account lowers the error threshold. When using a local sequence-structure alignment for the distance, we observed a smoother evolution of the fitness over time. Finally, in addition to the well known error threshold, we identify another threshold of the mutation rate, called divergence threshold, where the qualitative transient behavior changes from a localized to an exploratory search.},
author = {Anne Kupczok and Dittrich,Peter},
journal = {Journal of Theoretical Biology},
number = {3},
pages = {726 -- 35},
publisher = {Elsevier},
title = {{Determinants of simulated RNA evolution.}},
doi = {10.1016/j.jtbi.2005.06.019},
volume = {238},
year = {2006},
}
@article{3811,
abstract = {Networks of GABAergic neurons are key elements in the generation of gamma oscillations in the brain. Computational studies suggested that the emergence of coherent oscillations requires hyperpolarizing inhibition. Here, we show that GABA(A) receptor-mediated inhibition in mature interneurons of the hippocampal dentate gyrus is shunting rather than hyperpolarizing. Unexpectedly, when shunting inhibition is incorporated into a structured interneuron network model with fast and strong synapses, coherent oscillations emerge. In comparison to hyperpolarizing inhibition, networks with shunting inhibition show several advantages. First, oscillations are generated with smaller tonic excitatory drive. Second, network frequencies are tuned to the gamma band. Finally, robustness against heterogeneity in the excitatory drive is markedly improved. In single interneurons, shunting inhibition shortens the interspike interval for low levels of drive but prolongs it for high levels, leading to homogenization of neuronal firing rates. Thus, shunting inhibition may confer increased robustness to gamma oscillations in the brain.},
author = {Vida, Imre and Bartos, Marlene and Peter Jonas},
journal = {Neuron},
number = {1},
pages = {107 -- 17},
publisher = {Elsevier},
title = {{Shunting inhibition improves robustness of gamma oscillations in hippocampal interneuron networks by homogenizing firing rates}},
doi = {10.1016/j.neuron.2005.11.036},
volume = {49},
year = {2006},
}
@article{3813,
abstract = {Hyperpolarization-activated channels (Ih or HCN channels) are widely expressed in principal neurons in the central nervous system. However, Ih in inhibitory GABAergic interneurons is less well characterized. We examined the functional properties of Ih in fast-spiking basket cells (BCs) of the dentate gyrus, using hippocampal slices from 17- to 21-day-old rats. Bath application of the Ih channel blocker ZD 7288 at a concentration of 30 microm induced a hyperpolarization of 5.7 +/- 1.5 mV, an increase in input resistance and a correlated increase in apparent membrane time constant. ZD 7288 blocked a hyperpolarization-activated current in a concentration-dependent manner (IC50, 1.4 microm). The effects of ZD 7288 were mimicked by external Cs+. The reversal potential of Ih was -27.4 mV, corresponding to a Na+ to K+ permeability ratio (PNa/PK) of 0.36. The midpoint potential of the activation curve of Ih was -83.9 mV, and the activation time constant at -120 mV was 190 ms. Single-cell expression analysis using reverse transcription followed by quantitative polymerase chain reaction revealed that BCs coexpress HCN1 and HCN2 subunit mRNA, suggesting the formation of heteromeric HCN1/2 channels. ZD 7288 increased the current threshold for evoking antidromic action potentials by extracellular stimulation, consistent with the expression of Ih in BC axons. Finally, ZD 7288 decreased the frequency of miniature inhibitory postsynaptic currents (mIPSCs) in hippocampal granule cells, the main target cells of BCs, to 70 +/- 4% of the control value. In contrast, the amplitude of mIPSCs was unchanged, consistent with the presence of Ih in inhibitory terminals. In conclusion, our results suggest that Ih channels are expressed in the somatodendritic region, axon and presynaptic elements of fast-spiking BCs in the hippocampus.},
author = {Aponte, Yexica and Lien, Cheng-Chang and Reisinger, Ellen and Peter Jonas},
journal = {Journal of Physiology},
number = {Pt 1},
pages = {229 -- 43},
publisher = {Wiley-Blackwell},
title = {{Hyperpolarization-activated cation channels in fast-spiking interneurons of rat hippocampus}},
doi = {10.1113/jphysiol.2005.104042},
volume = {574},
year = {2006},
}
@misc{3814,
abstract = {The axon terminals (mossy fibers) of hippocampal dentate granule cells form characteristic synaptic connections with large spines or excrescences of both hilar mossy cells and CA3 pyramidal neurons. Interneurons of the hilar region and area CA3 are also prominent targets of mossy fibers. The tracing of biocytin-filled mossy fibers and immunolabeling of target cells with interneuron markers has revealed that the majority of mossy fiber synapses project to gamma aminobutyric acid (GABA)-ergic inhibitory interneurons rather than to excitatory principal cells, although the functional implications of these quantitative differences are unclear. Following a brief description of the "classical" mossy fiber synapse on excrescences of CA3 pyramidal cells, the present review focuses on the contacts formed between granule cells and GABAergic interneurons, both normally and after synaptic reorganization. In response to deafferentation of mossy cell target cells, which include both granule cells and interneurons, mossy fibers "sprout" new axon collaterals that form a band of supragranular mossy fibers in the inner molecular layer of the dentate gyrus. Although most newly formed recurrent mossy fibers establish synapses with granule cells, there is an apparently convergent input of new mossy fibers onto GABA-immunoreactive interneuron dendrites that traverse the inner molecular layer. These mossy fiber-interneuron synapses in the dentate gyrus are observed in chronically epileptic rats and may be the structural correlate of the granule cell hyperinhibition observed in these animals in vivo. Together, the findings reviewed here establish mossy fiber synapses as an important component of inhibitory circuits in the hippocampus.},
author = {Frotscher, Michael and Peter Jonas and Sloviter, Robert S},
booktitle = {Cell and Tissue Research},
number = {2},
pages = {361 -- 7},
publisher = {Springer},
title = {{Synapses formed by normal and abnormal hippocampal mossy fibers (Review)}},
doi = {10.1007/s00441-006-0269-2},
volume = {326},
year = {2006},
}
@article{3815,
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, Josef and Engel, Dominique and Frotscher, Michael and Peter Jonas},
journal = {Pflugers Archiv : European Journal of Physiology},
number = {3},
pages = {361 -- 72},
publisher = {Springer},
title = {{Timing and efficacy of transmitter release at mossy fiber synapses in the hippocampal network}},
doi = {10.1007/s00424-006-0093-2},
volume = {453},
year = {2006},
}
@article{3817,
author = {Frotscher, Michael and Gundelfinger, Eckart and Peter Jonas and Neher, Erwin and Seeburg, Peter},
journal = {Cell and Tissue Research},
number = {2},
pages = {203 -- 4},
publisher = {Springer},
title = {{The most important recent advances in synapse research from my point of view--and what remains to be done}},
doi = {10.1007/s00441-006-0325-y},
volume = {326},
year = {2006},
}
@article{3818,
abstract = {Rigorous analysis of synaptic transmission in the central nervous system requires access to presynaptic terminals. However, cortical terminals have been largely inaccessible to presynaptic patch-clamp recording, due to their small size. Using improved patch-clamp techniques in brain slices, we recorded from mossy fiber terminals in the CA3 region of the hippocampus, which have a diameter of 2-5 microm. The major steps of improvement were the enhanced visibility provided by high-numerical aperture objectives and infrared illumination, the development of vibratomes with minimal vertical blade vibrations and the use of sucrose-based solutions for storage and cutting. Based on these improvements, we describe a protocol that allows us to routinely record from hippocampal mossy fiber boutons. Presynaptic recordings can be obtained in slices from both rats and mice. Presynaptic recordings can be also obtained in slices from transgenic mice in which terminals are labeled with enhanced green fluorescent protein.},
author = {Bischofberger, Josef and Engel, Dominique and Li, Liyi and Geiger, Jörg R and Peter Jonas},
journal = {Nature Protocols},
number = {4},
pages = {2075 -- 81},
publisher = {Nature Publishing Group},
title = {{Patch-clamp recording from mossy fiber terminals in hippocampal slices}},
doi = {10.1038/nprot.2006.312 },
volume = {1},
year = {2006},
}
@inproceedings{3888,
abstract = {A stochastic graph game is played by two players on a game graph with probabilistic transitions. We consider stochastic graph games with omega-regular winning conditions specified as Rabin or Streett objectives. These games are NP-complete and coNP-complete, respectively. The value of the game for a player at a state s given an objective Phi is the maximal probability with which the player can guarantee the satisfaction of Phi from s. We present a strategy-improvement algorithm to compute values in stochastic Rabin games, where an improvement step involves solving Markov decision processes (MDPs) and nonstochastic Rabin games. The algorithm also computes values for stochastic Streett games but does not directly yield an optimal strategy for Streett objectives. We then show how to obtain an optimal strategy for Streett objectives by solving certain nonstochastic Streett games.},
author = {Krishnendu Chatterjee and Thomas Henzinger},
pages = {375 -- 389},
publisher = {Schloss Dagstuhl - Leibniz-Zentrum für Informatik},
title = {{Strategy improvement for stochastic Rabin and Streett games}},
doi = {10.1007/11817949_25},
volume = {4137},
year = {2006},
}
@inproceedings{3889,
abstract = {We study observation-based strategies for two-player turn-based games on graphs with omega-regular objectives. An observation-based strategy relies on imperfect information about the history of a play, namely, on the past sequence of observations. Such games occur in the synthesis of a controller that does not see the private state of the plant. Our main results are twofold. First, we give a fixed-point algorithm for computing the set of states from which a player can win with a deterministic observation-based strategy for any omega-regular objective. The fixed point is computed in the lattice of antichains of state sets. This algorithm has the advantages of being directed by the objective and of avoiding an explicit subset construction on the game graph. Second, we give an algorithm for computing the set of states from which a player can win with probability 1 with a randomized observation-based strategy for a Buchi objective. This set is of interest because in the absence of perfect information, randomized strategies are more powerful than deterministic ones. We show that our algorithms are optimal by proving matching lower bounds.},
author = {Krishnendu Chatterjee and Doyen, Laurent and Thomas Henzinger and Raskin, Jean-François},
pages = {287 -- 302},
publisher = {Springer},
title = {{Algorithms for omega-regular games with imperfect information}},
doi = {10.1007/11874683_19},
volume = {4207},
year = {2006},
}
@inproceedings{3890,
abstract = {We consider two-player infinite games played on graphs. The games are concurrent, in that at each state the players choose their moves simultaneously and independently, and stochastic, in that the moves determine a probability distribution for the successor state. The value of a game is the maximal probability with which a player can guarantee the satisfaction of her objective. We show that the values of concurrent games with w-regular objectives expressed as parity conditions can be decided in NP boolean AND coNP. This result substantially improves the best known previous bound of 3EXPTIME. It also shows that the full class of concurrent parity games is no harder than the special case of turn-based stochastic reachability games, for which NP boolean AND coNP is the best known bound. While the previous, more restricted NP boolean AND coNP results for graph games relied on the existence of particularly simple (pure memoryless) optimal strategies, in concurrent games with parity objectives optimal strategies may not exist, and epsilon-optimal strategies (which achieve the value of the game within a parameter epsilon > 0) require in general both randomization and infinite memory. Hence our proof must rely on a more detailed analysis of strategies and, in addition to the main result, yields two results that are interesting on their own. First, we show that there exist epsilon-optimal strategies that in the limit coincide with memoryless strategies; this parallels the celebrated result of Mertens-Neyman for concurrent games with limit-average objectives. Second, we complete the characterization of the memory requirements for epsilon-optimal strategies for concurrent games with parity conditions, by showing that memoryless strategies suffice for epsilon-optimality for coBachi conditions.},
author = {Krishnendu Chatterjee and de Alfaro, Luca and Thomas Henzinger},
pages = {678 -- 687},
publisher = {SIAM},
title = {{The complexity of quantitative concurrent parity games}},
doi = {10.1145/1109557.1109631},
year = {2006},
}
@inproceedings{3891,
abstract = {We study infinite stochastic games played by two-players over a finite state space, with objectives specified by sets of infinite traces. The games are concurrent (players make moves simultaneously and independently), stochastic (the next state is determined by a probability distribution that depends on the current state and chosen moves of the players) and infinite (proceeds for infinite number of rounds). The analysis of concurrent stochastic games can be classified into: quantitative analysis, analyzing the optimum value of the game; and qualitative analysis, analyzing the set of states with optimum value 1. We consider concurrent games with tail objectives, i.e., objectives that are independent of the finite-prefix of traces, and show that the class of tail objectives are strictly richer than the omega-regular objectives. We develop new proof techniques to extend several properties of concurrent games with omega-regular objectives to concurrent games with tail objectives. We prove the positive limit-one property for tail objectives, that states for all concurrent games if the optimum value for a player is positive for a tail objective Phi at some state, then there is a state where the optimum value is 1 for Phi, for the player. We also show that the optimum values of zero-sum (strictly conflicting objectives) games with tail objectives can be related to equilibrium values of nonzero-sum (not strictly conflicting objectives) games with simpler reachability objectives. A consequence of our analysis presents a polynomial time reduction of the quantitative analysis of tail objectives to the qualitative analysis for the sub-class of one-player stochastic games (Markov decision processes).},
author = {Krishnendu Chatterjee},
pages = {256 -- 270},
publisher = {Springer},
title = {{Concurrent games with tail objectives}},
doi = {10.1007/11874683_17},
volume = {4207},
year = {2006},
}
@article{3908,
abstract = {It is commonly believed that both the average length and the frequency of microsatellites correlate with genome size. We have estimated the frequency and the average length for 69 perfect dinucleotide microsatellites in an insect with an exceptionally large genome: Chorthippus biguttulus (Orthoptera, Acrididae). Dinucleotide microsatellites are not more frequent in C. biguttulus, but repeat arrays are 1.4 to 2 times longer than in other insect species. The average repeat number in C. biguttulus lies in the range of higher vertebrates. Natural populations are highly variable. At least 30 alleles per locus were found and the expected heterozygosity is above 0.95 at all three loci studied. In contrast, the observed heterozygosity is much lower (≤0.51), which could be caused by long null alleles.},
author = {Ustinova, Jana and Achmann, Roland and Cremer, Sylvia and Mayer, Frieder},
journal = {Journal of Molecular Evolution},
number = {2},
pages = {158 -- 167},
publisher = {Springer},
title = {{Long repeats in a huge gemome: microsatellite loci in the grasshopper Chorthippus biguttulus}},
doi = {10.1007/s00239-005-0022-6},
volume = {62},
year = {2006},
}
@article{3912,
abstract = {Invasive species often dramatically change native species communities by directly and indirectly out-competing native species. We studied the direct interference abilities of the invasive garden ant, Lasius neglectus VAN LOON, BOOMSMA & ANDRÁSFALVY, 1990, by performing one-to-one aggression tests of L. neglectus workers towards three native Lasius ant species that occur at the edge of a L. neglectus supercolony in Seva, Spain. Our results show that L. neglectus is highly aggressive against all three native Lasius species tested (L. grandis FOREL, 1909, L. emarginatus (OLIVIER, 1792), and L. cinereus SEIFERT, 1992), expressed as a higher attack rate of L. neglectus and behavioural dominance throughout the aggressive encounters. Attacks of L. neglectus were performed fastest and most frequent against L. grandis, and also the highest antennation frequencies were observed in encounters between these two species. This could be due to the largest difference in body size, or due to a greater overlap in ecological niche between L. neglectus and L. grandis compared to the other two native species. There was only weak support for L. neglectus workers from the periphery of the supercolony to be more aggressive relative to workers from the centre, even though the former encounter native ant species on a daily basis at the edge of the supercolony.},
author = {Cremer, Sylvia and Ugelvig, Line V and Lommen, Suzanne and Petersen, Klaus and Pedersen, Jes},
journal = {Myrmecological News},
pages = {13 -- 19},
publisher = {Österreichische Gesellschaft für Entomofaunistik},
title = {{Attack of the invasive garden ant: aggression behaviour of Lasius neglectus (Hymenoptera: Formicidae) against native Lasius species in Spain}},
volume = {9},
year = {2006},
}
@article{3913,
abstract = {Many invasive ant species, such as the Argentine ant or the red imported fire ant, have huge colonies with thousands of mass-foraging workers, which quickly monopolise resources and therefore represent a considerable threat to the native ant fauna. Cardiocondyla obscurior and several other species of this myrmicine genus have similarly been transferred throughout the tropics by human activities. However, because their colonies are tiny and workers forage solitarily, Cardiocondyla are often not recognized as successful invaders. Here, we document that the life history of Cardiocondyla closely resembles that of the more conspicuous tramp species, with polygyny, intranidal mating, budding, worker sterility, low genetic variability, and possibly also unicoloniality. Given that introduced Cardiocondyla may locally reach a very high population density, the effects of these stealthy invaders on the native arthropod fauna should receive more attention.},
author = {Heinze, Jürgen and Cremer, Sylvia and Eckl, Norbert and Schrempf, Alexandra},
journal = {Insectes Sociaux},
number = {1},
pages = {1 -- 7},
publisher = {Springer},
title = {{Stealthy invaders: the biology of Cardiocondyla tramp ants}},
doi = {10.1007/s00040-005-0847-4},
volume = {53},
year = {2006},
}
@article{3914,
abstract = {We compare the performances of established means of character selection for discriminant analysis in species distinction with a combination procedure for finding the optimal character combination (minimum classification error, minimum number of required characters), using morphometric data sets from the ant genera Cardiocondyla, Lasius and Tetramorium. The established methods are empirical character selection as well as forward selection, backward elimination and stepwise selection of discriminant analysis. The combination procedure is clearly superior to the established methods of character selection, and is widely applicable.},
author = {Moder, Karl and Schlick Steiner, Birgit and Steiner, Florian and Cremer, Sylvia and Christian, Erhard and Seifert, Bernhard},
journal = {Journal of Zoological Systematics and Evolutionary Research},
number = {1},
pages = {82 -- 87},
publisher = {Wiley-Blackwell},
title = {{Optimal species distinction by discriminant analysis: comparing established methods of character selection with a combination procedure using ant morphometrics as a case study}},
doi = {10.1111/j.1439-0469.2006.00372.x},
volume = {45},
year = {2006},
}
@article{3932,
abstract = {OBJECTIVES: The EGFR is expressed in malignant ovarian tumor tissue, and tissue content of EGFR has been directly associated with poor prognosis in patients with ovarian cancer. The uPA system plays a role in pericellular proteolysis, cell migration, invasion, and is over-expressed in ovarian cancer. This study explored the effects of EGF on uPAR expression in the ovarian cancer cell line OVCAR-3. METHODS: We used OVCAR-3 cells and the following methods: cell migration assay, time-lapse video microscopy, real-time PCR, assays for cellular binding of 125I-uPA and cellular degradation of 125I-uPA:PAI-1 complex, biosynthetic labeling using 35S-methionin, Western blot, Northern blot, and ELISAs for uPA, PAI-1, and uPAR. RESULTS: EGF up-regulates both protein and mRNA not only for uPAR, but also for the ligand uPA and its inhibitor PAI-1. Cell surface uPAR, in control as well as EGF-stimulated cells, is present only in the intact, not the cleaved, form. Ligand binding experiments showed an increase of endogenously occupied uPAR, whereas non-occupied receptor sites were not increased. In addition, EGF treatment resulted in decreased degradation of radiolabeled uPA:PAI-1 complex. This suggests decreased internalization of uPAR, since the complex is internalized together with uPAR. Like EGF, colchicine, which inhibits endocytosis, increased cell surface expression of uPAR. In addition, we found an immediate increase of uPAR after exposing the cells to EGF and this was accompanied by a transient increase of cell migration. The increase of cell surface uPAR in response to EGF is accompanied by increased release of the soluble form of uPAR (suPAR) to the medium as well as by increased cell migration. Both uPAR and suPAR increased in cells treated with the endocytosis inhibitor colchicine even though cell migration was inhibited, suggesting that the mechanism of uPAR shedding is not related to cell migration. CONCLUSION: Increased cell surface uPAR in response to EGF stimulation results from mobilization of uPAR from detergent-resistant domains, increased expression of uPAR mRNA, and decreased internalization and degradation of uPAR. Both the anti-uPAR antibody R3, which inhibits binding of uPA, and the EGFR phosphorylation inhibitor Iressa inhibited cell migration in response to uPA as well as to EGF, suggesting that EGFR and uPAR are engaged in the same multiprotein assembly on the cell surface.},
author = {Henic, Emir and Michael Sixt and Hansson, Stefan and Høyer-Hansen, Gunilla and Casslén, Bertil},
journal = {Gynecologic Oncology},
number = {1},
pages = {28 -- 39},
publisher = {Elsevier},
title = {{EGF-stimulated migration in ovarian cancer cells is associated with decreased internalization, increased surface expression, and increased shedding of the urokinase plasminogen activator receptor}},
doi = {10.1016/j.ygyno.2005.09.038},
volume = {101},
year = {2006},
}
@article{3934,
abstract = {T cells develop in the thymus in a highly specialized cellular and extracellular microenvironment. The basement membrane molecule, laminin-5 (LN-5), is predominantly found in the medulla of the human thymic lobules. Using high-resolution light microscopy, we show here that LN-5 is localized in a bi-membranous conduit-like structure, together with other typical basement membrane components including collagen type IV, nidogen and perlecan. Other interstitial matrix components, such as fibrillin-1 or -2, tenascin-C or fibrillar collagen types, were also associated with these structures. Three-dimensional (3D) confocal microscopy suggested a tubular structure, whereas immunoelectron and transmission electron microscopy showed that the core of these tubes contained fibrillar collagens enwrapped by the LN-5-containing membrane. These medullary conduits are surrounded by thymic epithelial cells, which in vitro were found to bind LN-5, but also fibrillin and tenascin-C. Dendritic cells were also detected in close vicinity to the conduits. Both of these stromal cell types express major histocompatibility complex (MHC) class II molecules capable of antigen presentation. The conduits are connected to blood vessels but, with an average diameter of 2 mum, they are too small to transport cells. However, evidence is provided that smaller molecules such as a 10 kDa dextran, but not large molecules (>500 kDa), can be transported in the conduits. These results clearly demonstrate that a conduit system, which is also known from secondary lymphatic organs such as lymph nodes and spleen, is present in the medulla of the human thymus, and that it might serve to transport small blood-borne molecules or chemokines to defined locations within the medulla.},
author = {Drumea-Mirancea, Mihaela and Wessels, Johannes T and Müller, Claudia A and Essl, Mike and Eble, Johannes A and Tolosa, Eva and Koch, Manuel and Reinhardt, Dieter P and Michael Sixt and Sorokin, Lydia and Stierhof, York-Dieter and Schwarz, Heinz and Klein, Gerd},
journal = {Journal of Cell Science},
number = {Pt 7},
pages = {1396 -- 1405},
publisher = {Company of Biologists},
title = {{Characterization of a conduit system containing laminin-5 in the human thymus: a potential transport system for small molecules}},
doi = {10.1242/jcs.02840},
volume = {119},
year = {2006},
}