@article{1050, abstract = {We present experimentally derived potential curves 1?and spin-orbit interaction functions for the strongly perturbed AΣu+ 3?and bΠu states of the cesium dimer. The results are based on data from several sources. Laser-induced fluorescence Fourier transform spectroscopy (LIF FTS) was used some time ago in the Laboratoire Aimé Cotton primarily to study the XΣg+ state. More recent work at Tsinghua University provides information from moderate 3?resolution spectroscopy on the lowest levels of the bΠ0u± state as well as additional high-resolution data. From Innsbruck University, we have precision data obtained with cold Cs2 molecules. Recent data from Temple University was obtained using the optical-optical double resonance polarization spectroscopy technique, and finally, a group at the University of Latvia has added additional LIF FTS data. In the Hamiltonian matrix, we have used analytic potentials (the expanded Morse oscillator form) with both finite-difference (FD) coupled-channel and discrete variable representation (DVR) calculations of the term values. Fitted diagonal and off-diagonal spin-orbit functions are obtained and compared with ab initio results from Temple and Moscow State universities.}, author = {Bai, Jianmei and Ahmed, Ergin and Beser, Bediha and Guan, Yafei and Kotochigova, Svetlana and Lyyra, Marjatta and Ashman, Seth and Wolfe, Christopher and Huennekens, John and Xie, Feng and Li, Dan and Li, Li and Tamanis, Maris and Ferber, Ruvin and Drozdova, Anastasia and Pazyuk, Elena and Stolyarov, Andrey and Danzl, Johann G and Nägerl, Hanns and Bouloufa, Nadia and Dulieu, Olivier and Amiot, Claude and Salami, Houssam and Bergeman, Thomas}, journal = { Physical Review A - Atomic, Molecular, and Optical Physics}, number = {3}, publisher = {American Physical Society}, title = {{Global analysis of data on the spin-orbit-coupled A 1Σu+ and b 3Πu inf states of Cs2}}, doi = {10.1103/PhysRevA.83.032514}, volume = {83}, year = {2011}, } @article{1051, abstract = {We demonstrate the temporal Talbot effect for trapped matter waves using ultracold atoms in an optical lattice. We investigate the phase evolution of an array of essentially non-interacting matter waves and observe matter-wave collapse and revival in the form of a Talbot interference pattern. By using long expansion times, we image momentum space with sub-recoil resolution, allowing us to observe fractional Talbot fringes up to tenth order.}, author = {Mark, Manfred and Haller, Elmar and Danzl, Johann G and Lauber, Katharina and Gustavsson, Mattias and Nägerl, Hanns}, journal = {New Journal of Physics}, publisher = {IOP Publishing Ltd.}, title = {{Demonstration of the temporal matter-wave Talbot effect for trapped matter waves}}, doi = {10.1088/1367-2630/13/8/085008}, volume = {13}, year = {2011}, } @article{1052, abstract = {The present paper aims at finding optimal parameters for trapping of Cs 2 molecules in optical lattices, with the perspective of creating a quantum degenerate gas of ground-state molecules. We have calculated dynamic polarizabilities of Cs 2 molecules subject to an oscillating electric field, using accurate potential curves and electronic transition dipole moments. We show that for some particular wavelengths of the optical lattice, called "magic wavelengths", the polarizability of the ground-state molecules is equal to the one of a Feshbach molecule. As the creation of the sample of ground-state molecules relies on an adiabatic population transfer from weakly-bound molecules created on a Feshbach resonance, such a coincidence ensures that both the initial and final states are favorably trapped by the lattice light, allowing optimized transfer in agreement with the experimental observation.}, author = {Vexiau, Romain and Bouloufa, Nadia and Aymar, Mireille and Danzl, Johann G and Mark, Manfred and Nägerl, Hanns and Dulieu, Olivier}, journal = {European Physical Journal D}, number = {1-2}, pages = {243 -- 250}, publisher = {Springer}, title = {{Optimal trapping wavelengths of Cs 2 molecules in an optical lattice}}, doi = {10.1140/epjd/e2011-20085-4}, volume = {65}, year = {2011}, } @article{1053, abstract = {We perform precision measurements on a Mott-insulator quantum state of ultracold atoms with tunable interactions. We probe the dependence of the superfluid-to-Mott-insulator transition on the interaction strength and explore the limits of the standard Bose-Hubbard model description. By tuning the on-site interaction energies to values comparable to the interband separation, we are able to quantitatively measure number-dependent shifts in the excitation spectrum caused by effective multibody interactions.}, author = {Mark, Manfred and Haller, Elmar and Lauber, Katharina and Danzl, Johann G and Daley, Andrew and Nägerl, Hanns}, journal = {Physical Review Letters}, number = {17}, publisher = {American Physical Society}, title = {{Precision measurements on a tunable Mott insulator of ultracold atoms}}, doi = {10.1103/PhysRevLett.107.175301}, volume = {107}, year = {2011}, } @article{1054, abstract = {We investigate local three-body correlations for bosonic particles in three dimensions and one dimension as a function of the interaction strength. The three-body correlation function g(3) is determined by measuring the three-body recombination rate in an ultracold gas of Cs atoms. In three dimensions, we measure the dependence of g(3) on the gas parameter in a BEC, finding good agreement with the theoretical prediction accounting for beyond-mean-field effects. In one dimension, we observe a reduction of g( 3) by several orders of magnitude upon increasing interactions from the weakly interacting BEC to the strongly interacting Tonks-Girardeau regime, in good agreement with predictions from the Lieb-Liniger model for all strengths of interaction.}, author = {Haller, Elmar and Rabie, Mahmoud and Mark, Manfred and Danzl, Johann G and Hart, Russell and Lauber, Katharina and Pupillo, Guido and Nägerl, Hanns}, journal = {Physical Review Letters}, number = {23}, publisher = {American Physical Society}, title = {{Three-body correlation functions and recombination rates for bosons in three dimensions and one dimension}}, doi = {10.1103/PhysRevLett.107.230404}, volume = {107}, year = {2011}, } @inproceedings{757, abstract = {Synchronous distributed algorithms are easier to design and prove correct than algorithms that tolerate asynchrony. Yet, in the real world, networks experience asynchrony and other timing anomalies. In this paper, we address the question of how to efficiently transform an algorithm that relies on synchronization into an algorithm that tolerates asynchronous executions. We introduce a transformation technique from synchronous algorithms to indulgent algorithms [1], which induces only a constant overhead in terms of time complexity in well-behaved executions. Our technique is based on a new abstraction we call an asynchrony detector, which the participating processes implement collectively. The resulting transformation works for a large class of colorless tasks, including consensus and set agreement. Interestingly, we also show that our technique is relevant for colored tasks, by applying it to the renaming problem, to obtain the first indulgent renaming algorithm.}, author = {Alistarh, Dan-Adrian and Gilbert, Seth and Guerraoui, Rachid and Travers, Corentin}, pages = {41 -- 52}, publisher = {Springer}, title = {{Generating fast indulgent algorithms}}, doi = {10.1007/978-3-642-17679-1_4}, volume = {6522 LNCS}, year = {2011}, } @inproceedings{759, abstract = {We study the complexity of renaming, a fundamental problem in distributed computing in which a set of processes need to pick distinct names from a given namespace. We prove an individual lower bound of Ω(k) process steps for deterministic renaming into any namespace of size sub-exponential in k, where k is the number of participants. This bound is tight: it draws an exponential separation between deterministic and randomized solutions, and implies new tight bounds for deterministic fetch-and-increment registers, queues and stacks. The proof of the bound is interesting in its own right, for it relies on the first reduction from renaming to another fundamental problem in distributed computing: mutual exclusion. We complement our individual bound with a global lower bound of Ω(k log (k/c)) on the total step complexity of renaming into a namespace of size ck, for any c ≥ 1. This applies to randomized algorithms against a strong adversary, and helps derive new global lower bounds for randomized approximate counter and fetch-and-increment implementations, all tight within logarithmic factors.}, author = {Alistarh, Dan-Adrian and Aspnes, James and Gilbert, Seth and Guerraoui, Rachid}, pages = {718 -- 727}, publisher = {IEEE}, title = {{The complexity of renaming}}, doi = {10.1109/FOCS.2011.66}, year = {2011}, } @inproceedings{760, abstract = {A randomized implementation is given of a test-and-set register with O(log log n) individual step complexity and O(n) total step complexity against an oblivious adversary. The implementation is linearizable and multi-shot, and shows an exponential complexity improvement over previous solutions designed to work against a strong adversary.}, author = {Alistarh, Dan-Adrian and Aspnes, James}, pages = {97 -- 109}, publisher = {Springer}, title = {{Sub-logarithmic test-and-set against a weak adversary}}, doi = {10.1007/978-3-642-24100-0_7}, volume = {6950 LNCS}, year = {2011}, } @inproceedings{761, abstract = {We give two new randomized algorithms for strong renaming, both of which work against an adaptive adversary in asynchronous shared memory. The first uses repeated sampling over a sequence of arrays of decreasing size to assign unique names to each of n processes with step complexity O(log3 n). The second transforms any sorting network into a strong adaptive renaming protocol, with an expected cost equal to the depth of the sorting network. Using an AKS sorting network, this gives a strong adaptive renaming algorithm with step complexity O(log k), where k is the contention in the current execution. We show this to be optimal based on a classic lower bound of Jayanti. We also show that any such strong renaming protocol can be used to build a monotone-consistent counter with logarithmic step complexity (at the cost of adding a max register) or a linearizable fetch-and-increment register (at the cost of increasing the step complexity by a logarithmic factor).}, author = {Alistarh, Dan-Adrian and Aspnes, James and Censor Hillel, Keren and Gilbert, Seth and Zadimoghaddam, Morteza}, pages = {239 -- 248}, publisher = {ACM}, title = {{Optimal-time adaptive strong renaming, with applications to counting}}, doi = {10.1145/1993806.1993850}, year = {2011}, } @article{7701, abstract = {During assembly of the Drosophila olfactory circuit, projection neuron (PN) dendrites prepattern the developing antennal lobe before the arrival of axons from their presynaptic partners, the adult olfactory receptor neurons (ORNs). We previously found that levels of transmembrane Semaphorin-1a, which acts as a receptor, instruct PN dendrite targeting along the dorsolateral-ventromedial axis. Here we show that two secreted semaphorins, Sema-2a and Sema-2b, provide spatial cues for PN dendrite targeting. Sema-2a and Sema-2b proteins are distributed in gradients opposing the Sema-1a protein gradient, and Sema-1a binds to Sema-2a-expressing cells. In Sema-2a and Sema-2b double mutants, PN dendrites that normally target dorsolaterally in the antennal lobe mistarget ventromedially, phenocopying cell-autonomous Sema-1a removal from these PNs. Cell ablation, cell-specific knockdown, and rescue experiments indicate that secreted semaphorins from degenerating larval ORN axons direct dendrite targeting. Thus, a degenerating brain structure instructs the wiring of a developing circuit through the repulsive action of secreted semaphorins.}, author = {Sweeney, Lora Beatrice Jaeger and Chou, Ya-Hui and Wu, Zhuhao and Joo, William and Komiyama, Takaki and Potter, Christopher J. and Kolodkin, Alex L. and Garcia, K. Christopher and Luo, Liqun}, issn = {0896-6273}, journal = {Neuron}, number = {5}, pages = {734--747}, publisher = {Elsevier}, title = {{Secreted semaphorins from degenerating larval ORN axons direct adult projection neuron dendrite targeting}}, doi = {10.1016/j.neuron.2011.09.026}, volume = {72}, year = {2011}, } @article{7702, abstract = {Longitudinal axon fascicles within the Drosophila embryonic CNS provide connections between body segments and are required for coordinated neural signaling along the anterior-posterior axis. We show here that establishment of select CNS longitudinal tracts and formation of precise mechanosensory afferent innervation to the same CNS region are coordinately regulated by the secreted semaphorins Sema-2a and Sema-2b. Both Sema-2a and Sema-2b utilize the same neuronal receptor, plexin B (PlexB), but serve distinct guidance functions. Localized Sema-2b attraction promotes the initial assembly of a subset of CNS longitudinal projections and subsequent targeting of chordotonal sensory afferent axons to these same longitudinal connectives, whereas broader Sema-2a repulsion serves to prevent aberrant innervation. In the absence of Sema-2b or PlexB, chordotonal afferent connectivity within the CNS is severely disrupted, resulting in specific larval behavioral deficits. These results reveal that distinct semaphorin-mediated guidance functions converge at PlexB and are critical for functional neural circuit assembly.}, author = {Wu, Zhuhao and Sweeney, Lora Beatrice Jaeger and Ayoob, Joseph C. and Chak, Kayam and Andreone, Benjamin J. and Ohyama, Tomoko and Kerr, Rex and Luo, Liqun and Zlatic, Marta and Kolodkin, Alex L.}, issn = {0896-6273}, journal = {Neuron}, number = {2}, pages = {281--298}, publisher = {Elsevier}, title = {{A combinatorial semaphorin code instructs the initial steps of sensory circuit assembly in the Drosophila CNS}}, doi = {10.1016/j.neuron.2011.02.050}, volume = {70}, year = {2011}, } @article{7750, author = {Robinson, Matthew Richard}, issn = {1465-7279}, journal = {Behavioral Ecology}, number = {6}, pages = {1143--1144}, publisher = {Oxford University Press}, title = {{Understanding intrasexual competition and sexual selection requires an evolutionary ecology framework}}, doi = {10.1093/beheco/arr110}, volume = {22}, year = {2011}, } @article{8025, abstract = {Chandelier (axoaxonic) cells (ChCs) are a distinct group of GABAergic interneurons that innervate the axon initial segments of pyramidal cells. However, their circuit role and the function of their clearly defined anatomical specificity remain unclear. Recent work has demonstrated that chandelier cells can produce depolarizing GABAergic PSPs, occasionally driving postsynaptic targets to spike. On the other hand, other work suggests that ChCs are hyperpolarizing and may have an inhibitory role. These disparate functional effects may reflect heterogeneity among ChCs. Here, using brain slices from transgenic mouse strains, we first demonstrate that, across different neocortical areas and genetic backgrounds, upper Layer 2/3 ChCs belong to a single electrophysiologically and morphologically defined population, extensively sampling Layer 1 inputs with asymmetric dendrites. Consistent with being a single cell type, we find electrical coupling between ChCs. We then investigate the effect of chandelier cell activation on pyramidal neuron spiking in several conditions, ranging from the resting membrane potential to stimuli designed to approximate in vivo membrane potential dynamics. We find that under quiescent conditions, chandelier cells are capable of both promoting and inhibiting spike generation, depending on the postsynaptic membrane potential. However, during in vivo-like membrane potential fluctuations, the dominant postsynaptic effect was a strong inhibition. Thus, neocortical chandelier cells, even from within a homogeneous population, appear to play a dual role in the circuit, helping to activate quiescent pyramidal neurons, while at the same time inhibiting active ones.}, author = {Woodruff, A. R. and McGarry, L. M. and Vogels, Tim P and Inan, M. and Anderson, S. A. and Yuste, R.}, issn = {0270-6474}, journal = {Journal of Neuroscience}, number = {49}, pages = {17872--17886}, publisher = {Society for Neuroscience}, title = {{State-dependent function of neocortical chandelier cells}}, doi = {10.1523/jneurosci.3894-11.2011}, volume = {31}, year = {2011}, } @article{8074, abstract = {Cortical neurons receive balanced excitatory and inhibitory synaptic currents. Such a balance could be established and maintained in an experience-dependent manner by synaptic plasticity at inhibitory synapses. We show that this mechanism provides an explanation for the sparse firing patterns observed in response to natural stimuli and fits well with a recently observed interaction of excitatory and inhibitory receptive field plasticity. The introduction of inhibitory plasticity in suitable recurrent networks provides a homeostatic mechanism that leads to asynchronous irregular network states. Further, it can accommodate synaptic memories with activity patterns that become indiscernible from the background state but can be reactivated by external stimuli. Our results suggest an essential role of inhibitory plasticity in the formation and maintenance of functional cortical circuitry.}, author = {Vogels, Tim P and Sprekeler, H. and Zenke, F. and Clopath, C. and Gerstner, W.}, issn = {0036-8075}, journal = {Science}, number = {6062}, pages = {1569--1573}, publisher = {American Association for the Advancement of Science}, title = {{Inhibitory plasticity balances excitation and inhibition in sensory pathways and memory networks}}, doi = {10.1126/science.1211095}, volume = {334}, year = {2011}, } @article{8464, abstract = {Nonsymmetric motion: Solid‐state NMR measurements of dipolar coupling tensors provide insight into protein dynamics. The hitherto ignored asymmetry of the dipolar coupling tensor contains valuable information about motional asymmetry, which was used in the first direct site‐resolved measurement of such tensors. Important motions such as rotamer jumps can now be directly detected in the solid state.}, author = {Schanda, Paul and Huber, Matthias and Boisbouvier, Jérôme and Meier, Beat H. and Ernst, Matthias}, issn = {1433-7851}, journal = {Angewandte Chemie International Edition}, number = {46}, pages = {11005--11009}, publisher = {Wiley}, title = {{Solid-state NMR measurements of asymmetric dipolar couplings provide insight into protein side-chain motion}}, doi = {10.1002/anie.201103944}, volume = {50}, year = {2011}, } @article{8468, author = {Lalli, Daniela and Schanda, Paul and Chowdhury, Anup and Retel, Joren and Hiller, Matthias and Higman, Victoria A. and Handel, Lieselotte and Agarwal, Vipin and Reif, Bernd and van Rossum, Barth and Akbey, Ümit and Oschkinat, Hartmut}, issn = {0925-2738}, journal = {Journal of Biomolecular NMR}, number = {4}, pages = {477--485}, publisher = {Springer Nature}, title = {{Three-dimensional deuterium-carbon correlation experiments for high-resolution solid-state MAS NMR spectroscopy of large proteins}}, doi = {10.1007/s10858-011-9578-1}, volume = {51}, year = {2011}, } @article{8469, abstract = {The accurate experimental determination of dipolar-coupling constants for one-bond heteronuclear dipolar couplings in solids is a key for the quantification of the amplitudes of motional processes. Averaging of the dipolar coupling reports on motions on time scales up to the inverse of the coupling constant, in our case tens of microseconds. Combining dipolar-coupling derived order parameters that characterize the amplitudes of the motion with relaxation data leads to a more precise characterization of the dynamical parameters and helps to disentangle the amplitudes and the time scales of the motional processes, which impact relaxation rates in a highly correlated way. Here. we describe and characterize an improved experimental protocol – based on REDOR – to measure these couplings in perdeuterated proteins with a reduced sensitivity to experimental missettings. Because such effects are presently the dominant source of systematic errors in experimental dipolar-coupling measurements, these compensated experiments should help to significantly improve the precision of such data. A detailed comparison with other commonly used pulse sequences (T-MREV, phase-inverted CP,R18 5/2, and R18 7/1) is provided.}, author = {Schanda, Paul and Meier, Beat H. and Ernst, Matthias}, issn = {1090-7807}, journal = {Journal of Magnetic Resonance}, keywords = {Nuclear and High Energy Physics, Biophysics, Biochemistry, Condensed Matter Physics}, number = {2}, pages = {246--259}, publisher = {Elsevier}, title = {{Accurate measurement of one-bond H–X heteronuclear dipolar couplings in MAS solid-state NMR}}, doi = {10.1016/j.jmr.2011.03.015}, volume = {210}, year = {2011}, } @article{8470, abstract = {Adding a new dimension: 4D or 3D proton‐detected spectra of perdeuterated protein samples with 1H labelled amides and methyl groups permit collecting unambiguous distance restraints with high sensitivity and determining protein structure by solid‐state NMR (see picture).}, author = {Huber, Matthias and Hiller, Sebastian and Schanda, Paul and Ernst, Matthias and Böckmann, Anja and Verel, René and Meier, Beat H.}, issn = {1439-4235}, journal = {ChemPhysChem}, keywords = {Physical and Theoretical Chemistry, Atomic and Molecular Physics, and Optics}, number = {5}, pages = {915--918}, publisher = {Wiley}, title = {{A proton-detected 4D solid-state NMR experiment for protein structure determination}}, doi = {10.1002/cphc.201100062}, volume = {12}, year = {2011}, } @article{8471, abstract = {Despite the importance of protein fibrils in the context of conformational diseases, information on their structure is still sparse. Hydrogen/deuterium exchange measurements of backbone amide protons allow the identification hydrogen-bonding patterns and reveal pertinent information on the amyloid β-sheet architecture. However, they provide only little information on the identity of residues exposed to solvent or buried inside the fibril core. NMR spectroscopy is a potent method for identifying solvent-accessible residues in proteins via observation of polarization transfer between chemically exchanging side-chain protons and water protons. We show here that the combined use of highly deuterated samples and fast magic-angle spinning greatly attenuates unwanted spin diffusion and allows identification of polarization exchange with the solvent in a site-specific manner. We apply this measurement protocol to HET-s(218–289) prion fibrils under different conditions (including physiological pH, where protofibrils assemble together into thicker fibrils) and demonstrate that each protofibril of HET-s(218–289), is surrounded by water, thus excluding the existence of extended dry interfibril contacts. We also show that exchangeable side-chain protons inside the hydrophobic core of HET-s(218–289) do not exchange over time intervals of weeks to months. The experiments proposed in this study can provide insight into the detailed structural features of amyloid fibrils in general.}, author = {Van Melckebeke, Hélène and Schanda, Paul and Gath, Julia and Wasmer, Christian and Verel, René and Lange, Adam and Meier, Beat H. and Böckmann, Anja}, issn = {0022-2836}, journal = {Journal of Molecular Biology}, number = {3}, pages = {765--772}, publisher = {Elsevier}, title = {{Probing water accessibility in HET-s(218–289) amyloid fibrils by solid-state NMR}}, doi = {10.1016/j.jmb.2010.11.004}, volume = {405}, year = {2011}, } @article{8505, abstract = {The classical principle of least action says that orbits of mechanical systems extremize action; an important subclass are those orbits that minimize action. In this paper we utilize this principle along with Aubry-Mather theory to construct (Birkhoff) regions of instability for a certain three-body problem, given by a Hamiltonian system of 2 degrees of freedom. We believe that these methods can be applied to construct instability regions for a variety of Hamiltonian systems with 2 degrees of freedom. The Hamiltonian model we consider describes dynamics of a Sun-Jupiter-comet system, and under some simplifying assumptions, we show the existence of instabilities for the orbit of the comet. In particular, we show that a comet which starts close to an orbit in the shape of an ellipse of eccentricity e=0.66 can increase in eccentricity up to e=0.96. In the sequels to this paper, we extend the result to beyond e=1 and show the existence of ejection orbits. Such orbits are initially well within the range of our solar system. This might give an indication of why most objects rotating around the Sun in our solar system have relatively low eccentricity.}, author = {Galante, Joseph and Kaloshin, Vadim}, issn = {0012-7094}, journal = {Duke Mathematical Journal}, keywords = {General Mathematics}, number = {2}, pages = {275--327}, publisher = {Duke University Press}, title = {{Destruction of invariant curves in the restricted circular planar three-body problem by using comparison of action}}, doi = {10.1215/00127094-1415878}, volume = {159}, year = {2011}, }