TY - JOUR AB - The electrolyte is one of the greatest challenges facing the development of the non‐aqueous Li–O2 battery. Although ether‐based electrolytes do from Li2O2 on the first discharge, it is shown by various techniques that they also decompose and that decomposition increases while Li2O2 decreases on cycling (see picture). Thus, these electrolytes are not suitable. AU - Freunberger, Stefan Alexander AU - Chen, Yuhui AU - Drewett, Nicholas E. AU - Hardwick, Laurence J. AU - Bardé, Fanny AU - Bruce, Peter G. ID - 7314 IS - 37 JF - Angewandte Chemie International Edition SN - 1433-7851 TI - The Lithium-Oxygen battery with ether-based electrolytes VL - 50 ER - TY - JOUR AB - Lithium-metal oxides with a high formal Li2O content, such as Li5FeO4 (5Li2O•Fe2O3) and a Li2MnO3•LiFeO2 composite ({Li2O•MnO2}•{Li2O•Fe2O3}) have been explored as electrocatalysts for primary and rechargeable Li-O2 cells. Activation occurs predominantly by Li2O removal, either electrochemically or chemically by acid-treatment. Superior electrochemical behavior is obtained if activation occurs by acid-treatment; Li2MnO3•LiFeO2 catalysts provide 2516 mAh/g (carbon) corresponding to 931 mAh/g (electrocatalyst + carbon) during the initial discharge. The reaction is reasonably reversible during the early cycles. The approach has implications for designing electrocatalysts that participate through electrochemical Li2O extraction/reformation reactions, offering exceptionally high capacities. AU - Trahey, L. AU - Johnson, C. S. AU - Vaughey, J. T. AU - Kang, S.-H. AU - Hardwick, L. J. AU - Freunberger, Stefan Alexander AU - Bruce, P. G. AU - Thackeray, M. M. ID - 7317 IS - 5 JF - Electrochemical and Solid-State Letters SN - 1099-0062 TI - Activated Lithium-Metal-Oxides as catalytic electrodes for Li–O2 cells VL - 14 ER - TY - JOUR AB - The nonaqueous rechargeable lithium–O2 battery containing an alkyl carbonate electrolyte discharges by formation of C3H6(OCO2Li)2, Li2CO3, HCO2Li, CH3CO2Li, CO2, and H2O at the cathode, due to electrolyte decomposition. Charging involves oxidation of C3H6(OCO2Li)2, Li2CO3, HCO2Li, CH3CO2Li accompanied by CO2 and H2O evolution. Mechanisms are proposed for the reactions on discharge and charge. The different pathways for discharge and charge are consistent with the widely observed voltage gap in Li–O2 cells. Oxidation of C3H6(OCO2Li)2 involves terminal carbonate groups leaving behind the OC3H6O moiety that reacts to form a thick gel on the Li anode. Li2CO3, HCO2Li, CH3CO2Li, and C3H6(OCO2Li)2 accumulate in the cathode on cycling correlating with capacity fading and cell failure. The latter is compounded by continuous consumption of the electrolyte on each discharge. AU - Freunberger, Stefan Alexander AU - Chen, Yuhui AU - Peng, Zhangquan AU - Griffin, John M. AU - Hardwick, Laurence J. AU - Bardé, Fanny AU - Novák, Petr AU - Bruce, Peter G. ID - 7316 IS - 20 JF - Journal of the American Chemical Society SN - 0002-7863 TI - Reactions in the rechargeable Lithium–O2 battery with alkyl carbonate electrolytes VL - 133 ER - TY - JOUR AB - Spectroscopic data (see picture) provide direct evidence that in non‐aqueous Li+ electrolyte, O2 is reduced to O2−, which then forms LiO2 on the electrode surface which disproportionates to Li2O2. On charging, Li2O2 decomposes directly, in a one‐step reaction to evolve O2 and does not pass through LiO2 as an intermediate. AU - Peng, Zhangquan AU - Freunberger, Stefan Alexander AU - Hardwick, Laurence J. AU - Chen, Yuhui AU - Giordani, Vincent AU - Bardé, Fanny AU - Novák, Petr AU - Graham, Duncan AU - Tarascon, Jean-Marie AU - Bruce, Peter G. ID - 7315 IS - 28 JF - Angewandte Chemie International Edition SN - 1433-7851 TI - Oxygen reactions in a non-aqueous Li+ electrolyte VL - 50 ER - TY - CONF AB - 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. AU - Alistarh, Dan-Adrian AU - Gilbert, Seth AU - Guerraoui, Rachid AU - Travers, Corentin ID - 757 TI - Generating fast indulgent algorithms VL - 6522 LNCS ER - TY - CONF AB - 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. AU - Alistarh, Dan-Adrian AU - Aspnes, James AU - Gilbert, Seth AU - Guerraoui, Rachid ID - 759 TI - The complexity of renaming ER - TY - CONF AB - 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). AU - Alistarh, Dan-Adrian AU - Aspnes, James AU - Censor Hillel, Keren AU - Gilbert, Seth AU - Zadimoghaddam, Morteza ID - 761 TI - Optimal-time adaptive strong renaming, with applications to counting ER - TY - CONF AB - 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. AU - Alistarh, Dan-Adrian AU - Aspnes, James ID - 760 TI - Sub-logarithmic test-and-set against a weak adversary VL - 6950 LNCS ER - TY - JOUR AU - Robinson, Matthew Richard ID - 7750 IS - 6 JF - Behavioral Ecology SN - 1465-7279 TI - Understanding intrasexual competition and sexual selection requires an evolutionary ecology framework VL - 22 ER - TY - JOUR AB - 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. AU - Woodruff, A. R. AU - McGarry, L. M. AU - Vogels, Tim P AU - Inan, M. AU - Anderson, S. A. AU - Yuste, R. ID - 8025 IS - 49 JF - Journal of Neuroscience SN - 0270-6474 TI - State-dependent function of neocortical chandelier cells VL - 31 ER - TY - JOUR AB - 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. AU - Vogels, Tim P AU - Sprekeler, H. AU - Zenke, F. AU - Clopath, C. AU - Gerstner, W. ID - 8074 IS - 6062 JF - Science SN - 0036-8075 TI - Inhibitory plasticity balances excitation and inhibition in sensory pathways and memory networks VL - 334 ER - TY - JOUR AB - 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. AU - Schanda, Paul AU - Meier, Beat H. AU - Ernst, Matthias ID - 8469 IS - 2 JF - Journal of Magnetic Resonance KW - Nuclear and High Energy Physics KW - Biophysics KW - Biochemistry KW - Condensed Matter Physics SN - 1090-7807 TI - Accurate measurement of one-bond H–X heteronuclear dipolar couplings in MAS solid-state NMR VL - 210 ER - TY - JOUR AB - 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). AU - Huber, Matthias AU - Hiller, Sebastian AU - Schanda, Paul AU - Ernst, Matthias AU - Böckmann, Anja AU - Verel, René AU - Meier, Beat H. ID - 8470 IS - 5 JF - ChemPhysChem KW - Physical and Theoretical Chemistry KW - Atomic and Molecular Physics KW - and Optics SN - 1439-4235 TI - A proton-detected 4D solid-state NMR experiment for protein structure determination VL - 12 ER - TY - JOUR AB - 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. AU - Schanda, Paul AU - Huber, Matthias AU - Boisbouvier, Jérôme AU - Meier, Beat H. AU - Ernst, Matthias ID - 8464 IS - 46 JF - Angewandte Chemie International Edition SN - 1433-7851 TI - Solid-state NMR measurements of asymmetric dipolar couplings provide insight into protein side-chain motion VL - 50 ER - TY - JOUR AU - Lalli, Daniela AU - Schanda, Paul AU - Chowdhury, Anup AU - Retel, Joren AU - Hiller, Matthias AU - Higman, Victoria A. AU - Handel, Lieselotte AU - Agarwal, Vipin AU - Reif, Bernd AU - van Rossum, Barth AU - Akbey, Ümit AU - Oschkinat, Hartmut ID - 8468 IS - 4 JF - Journal of Biomolecular NMR SN - 0925-2738 TI - Three-dimensional deuterium-carbon correlation experiments for high-resolution solid-state MAS NMR spectroscopy of large proteins VL - 51 ER - TY - JOUR AB - Recent discovery of the Large-billed Reed Warbler (Acrocephalus orinus) in museums and in the wild significantly expanded our knowledge of its morphological traits and genetic variability, and revealed new data on geographical distribution of the breeding grounds, migration routes and wintering locations of this species. It is now certain that A. orinus is breeding in Central Asia; however, the precise area of distribution remains unclear. The difficulty in the further study of this species lies in the small number of known specimens, with only 13 currently available in museums, and in the relative uncertainty of the breeding area and habitat of this species. Following morphological and genetic analyses from Svensson, et al, we describe 14 new A. orinus specimens from collections of Zoological Museums of the former USSR from the territory of Central Asian states. All of these specimens were erroneously labeled as Blyth's Reed Warbler (A. dumetorum), which is thought to be a breeding species in these areas. The 14 new A. orinus specimens were collected during breeding season while most of the 85 A. dumetorum specimens from the same area were collected during the migration period. Our data indicate that the Central Asian territory previously attributed as breeding grounds of A. dumetorum is likely to constitute the breeding territory of A. orinus. This rare case of a re-description of the breeding territory of a lost species emphasizes the importance of maintenance of museum collections around the world. If the present data on the breeding grounds of A. orinus are confirmed with field observations and collections, the literature on the biology of A. dumetorum from the southern part of its range may have to be reconsidered. AU - Koblik, Evgeniy A AU - Red'Kin, Yaroslav A AU - Meer, Margarita S AU - Derelle, Romain AU - Golenkina, Sofia A AU - Fyodor Kondrashov AU - Arkhipov, Vladimir Y ID - 890 IS - 4 JF - PLoS One TI - Acrocephalus orinus: A case of Mistaken identity VL - 6 ER - TY - JOUR AB - A popular method for generating micron-sized aerosols is to submerge ultrasonic (ω ∼ MHz) piezoelectric oscillators in a water bath. The submerged oscillator atomizes the fluid, creating droplets with radii proportional to the wavelength of the standing wave at the fluid surface. Classical theory for the Faraday instability predicts a parametric instability driving a capillary wave at the subharmonic (ω / 2) frequency. For many applications it is desirable to reduce the size of the droplets; however, using higher frequency oscillators becomes impractical beyond a few MHz. Observations are presented that demonstrate that smaller droplets may also be created by increasing the driving amplitude of the oscillator, and that this effect becomes more pronounced for large driving frequencies. It is shown that these observations are consistent with a transition from droplets associated with subharmonic (ω/2) capillary waves to harmonic (ω) capillary waves induced by larger driving frequencies and amplitudes, as predicted by a stability analysis of the capillary waves. AU - Higginbotham, Andrew P AU - Guillen, A AU - Jones, Nick AU - Donnelly, Tom AU - Bernoff, Andrew ID - 90 IS - 5 JF - Journal of the Acoustical Society of America TI - Evidence of the harmonic Faraday instability in ultrasonic atomization experiments with a deep, inviscid fluid VL - 130 ER - TY - JOUR AB - A cloud-resolving model is used to investigate the effect of warming on high percentiles of precipitation (precipitation extremes) in the idealized setting of radiative-convective equilibrium. While this idealized setting does not allow for several factors that influence precipitation in the tropics, it does allow for an evaluation of the response of precipitation extremes to warming in simulations with resolved rather than parameterized convection. The methodology developed should also be applicable to less idealized simulations. Modeled precipitation extremes are found to increase in magnitude in response to an increase in sea surface temperature. A dry static energy budget is used to relate the changes in precipitation extremes to changes in atmospheric temperature, vertical velocity, and precipitation efficiency. To first order, the changes in precipitation extremes are captured by changes in the mean temperature structure of the atmosphere. Changes in vertical velocities play a secondary role and tend to weaken the strength of precipitation extremes, despite an intensification of updraft velocities in the upper troposphere. The influence of changes in condensate transports on precipitation extremes is quantified in terms of a precipitation efficiency; it does not change greatly with warming. Tropical precipitation extremes have previously been found to increase at a greater fractional rate than the amount of atmospheric water vapor in observations of present-day variability and in some climate model simulations with parameterized convection. But the fractional increases in precipitation extremes in the cloud-resolving simulations are comparable in magnitude to those in surface water vapor concentrations (owing to a partial cancellation between dynamical and thermodynamical changes), and are substantially less than the fractional increases in column water vapor. AU - Muller, Caroline J AU - O’Gorman, Paul A. AU - Back, Larissa E. ID - 9144 IS - 11 JF - Journal of Climate KW - Atmospheric Science SN - 0894-8755 TI - Intensification of precipitation extremes with warming in a cloud-resolving model VL - 24 ER - TY - JOUR AB - Understanding and predicting the response of the hydrological cycle to climate change is a major challenge with important societal implications. Much progress has been made in understanding the response of global average precipitation by considering the energy balances of the atmosphere and the surface1,2,3,4,5,6. This energetic perspective reveals that changes in temperature, greenhouse gases, aerosols, solar forcing and cloud feedbacks can all affect the global average rate of precipitation5,7,8,9,10,11. Local precipitation changes have conventionally been analysed using the water vapour budget, but here we show that the energetic approach can be extended to local changes in precipitation by including changes in horizontal energy transport. In simulations of twenty-first century climate change, this energy transport accounts for much of the spatial variability in precipitation change. We show that changes in radiative and surface sensible heat fluxes are a guide to the local precipitation response over land and at large scales, but not at small scales over the ocean, where cloud and water vapour radiative feedbacks dampen the response. The energetic approach described here helps bridge the gap between our understanding of global and regional precipitation changes. It could be applied to better understand the response of regional precipitation to different radiative forcings, including geo-engineering schemes, as well as to understand the differences between the fast and slow responses of regional precipitation to such forcings. AU - Muller, Caroline J AU - O’Gorman, P. A. ID - 9143 IS - 5 JF - Nature Climate Change SN - 1758-678X TI - An energetic perspective on the regional response of precipitation to climate change VL - 1 ER - TY - JOUR AB - The conserved role of Notch signaling in controlling intestinal cell fate specification and homeostasis has been extensively studied. Nevertheless, the precise identity of the cells in which Notch signaling is active and the role of different Notch receptor paralogues in the intestine remain ambiguous, due to the lack of reliable tools to investigate Notch expression and function in vivo. We generated a new series of transgenic mice that allowed us, by lineage analysis, to formally prove that Notch1 and Notch2 are specifically expressed in crypt stem cells. In addition, a novel Notch reporter mouse, Hes1-EmGFP SAT, demonstrated exclusive Notch activity in crypt stem cells and absorptive progenitors. This roster of knock-in and reporter mice represents a valuable resource to functionally explore the Notch pathway in vivo in virtually all tissues. AU - Fré, Silvia AU - Hannezo, Edouard B AU - Šale, Sanja AU - Huyghe, Mathilde AU - Lafkas, Daniel AU - Kissel, Holger AU - Louvi, Angeliki AU - Greve, Jeffrey AU - Louvard, Daniel AU - Artavanis Tsakonas, Spyros ID - 923 IS - 10 JF - PLoS One TI - Notch lineages and activity in intestinal stem cells determined by a new set of knock in mice VL - 6 ER -