@inproceedings{21615, abstract = {Focused electron beams can induce electromagnetic radiation from periodic surfaces. We have used low-energy electrons (1.5-6kV) to induce visible light emission from nanoscale gratings (50nm and 60nm). Our results coincide well with numerical simulations.}, author = {Massuda, Aviram and Roques-Carmes, Charles and Yang, Yujia and Kooi, Steven E. and Yang, Yi and Murdia, Chitraang and Berggren, Karl K. and Kaminer, Ido and Soljačić, Marin}, booktitle = {Conference on Lasers and Electro-Optics}, location = {San Jose, CA, United States}, publisher = {Optica Publishing Group}, title = {{Smith-Purcell radiation from low-energy electrons}}, doi = {10.1364/cleo_qels.2017.fm3h.6}, year = {2017}, } @article{14007, abstract = {In a recent article by Hockett et al (2016 J. Phys. B: At. Mol. Opt. Phys. 49 095602), time delays arising in the context of molecular single-photon ionization are investigated from a theoretical point of view. We argue that one of the central equations given in this article is incorrect and present a reformulation that is consistent with the established treatment of angle-dependent scattering delays (Eisenbud 1948 PhD Thesis Princeton University; Wigner 1955 Phys. Rev. 98 145–7; Smith 1960 Phys. Rev. 118 349–6; Nussenzveig 1972 Phys. Rev. D 6 1534–42).}, author = {Baykusheva, Denitsa Rangelova and Wörner, Hans Jakob}, issn = {1361-6455}, journal = {Journal of Physics B: Atomic, Molecular and Optical Physics}, keywords = {Condensed Matter Physics, Atomic and Molecular Physics, and Optics}, number = {7}, publisher = {IOP Publishing}, title = {{Comment on ‘Time delays in molecular photoionization’}}, doi = {10.1088/1361-6455/aa62b5}, volume = {50}, year = {2017}, } @article{14009, abstract = {Attosecond delays between photoelectron wave packets emitted from different electronic shells are now well established. Is there any delay between electrons originating from the same electronic shell but leaving the cation in different fine-structure states? This question is relevant for all attosecond photoemission studies involving heavy elements, be it atoms, molecules or solids. We answer this fundamental question by measuring energy-dependent delays between photoelectron wave packets associated with the 2P3/2 and 2P1/2 components of the electronic groundstates of Xe+ and Kr+. We observe delays reaching up to 33±6 as in the case of Xe. Our results are compared with two state-of-the-art theories. Whereas both theories quantitatively agree with the results obtained for Kr, neither of them fully reproduces the experimental results in Xe. Performing delay measurements very close to the ionization thresholds, we compare the agreement of several analytical formulas for the continuum-continuum delays with experimental data. Our results show an important influence of spin-orbit coupling on attosecond photoionization delays, highlight the requirement for additional theory development, and offer a precision benchmark for such work.}, author = {Jordan, I. and Huppert, M. and Pabst, S. and Kheifets, A. S. and Baykusheva, Denitsa Rangelova and Wörner, H. J.}, issn = {2469-9934}, journal = {Physical Review A}, number = {1}, publisher = {American Physical Society}, title = {{Spin-orbit delays in photoemission}}, doi = {10.1103/physreva.95.013404}, volume = {95}, year = {2017}, } @inproceedings{487, abstract = {In this paper we study network architecture for unlicensed cellular networking for outdoor coverage in TV white spaces. The main technology proposed for TV white spaces is 802.11af, a Wi-Fi variant adapted for TV frequencies. However, 802.11af is originally designed for improved indoor propagation. We show that long links, typical for outdoor use, exacerbate known Wi-Fi issues, such as hidden and exposed terminal, and significantly reduce its efficiency. Instead, we propose CellFi, an alternative architecture based on LTE. LTE is designed for long-range coverage and throughput efficiency, but it is also designed to operate in tightly controlled and centrally managed networks. CellFi overcomes these problems by designing an LTE-compatible spectrum database component, mandatory for TV white space networking, and introducing an interference management component for distributed coordination. CellFi interference management is compatible with existing LTE mechanisms, requires no explicit communication between base stations, and is more efficient than CSMA for long links. We evaluate our design through extensive real world evaluation on of-the-shelf LTE equipment and simulations. We show that, compared to 802.11af, it increases coverage by 40% and reduces median flow completion times by 2.3x.}, author = {Baig, Ghufran and Radunovic, Bozidar and Alistarh, Dan-Adrian and Balkwill, Matthew and Karagiannis, Thomas and Qiu, Lili}, booktitle = {Proceedings of the 2017 13th International Conference on emerging Networking EXperiments and Technologies}, isbn = {978-145035422-6}, location = {Incheon, South Korea}, pages = {2 -- 14}, publisher = {ACM}, title = {{Towards unlicensed cellular networks in TV white spaces}}, doi = {10.1145/3143361.3143367}, year = {2017}, } @article{6117, abstract = {Interleukin-17 (IL-17) is a major pro-inflammatory cytokine: it mediates responses to pathogens or tissue damage, and drives autoimmune diseases. Little is known about its role in the nervous system. Here we show that IL-17 has neuromodulator-like properties in Caenorhabditis elegans. IL-17 can act directly on neurons to alter their response properties and contribution to behaviour. Using unbiased genetic screens, we delineate an IL-17 signalling pathway and show that it acts in the RMG hub interneurons. Disrupting IL-17 signalling reduces RMG responsiveness to input from oxygen sensors, and renders sustained escape from 21% oxygen transient and contingent on additional stimuli. Over-activating IL-17 receptors abnormally heightens responses to 21% oxygen in RMG neurons and whole animals. IL-17 deficiency can be bypassed by optogenetic stimulation of RMG. Inducing IL-17 expression in adults can rescue mutant defects within 6 h. These findings reveal a non-immunological role of IL-17 modulating circuit function and behaviour.}, author = {Chen, Changchun and Itakura, Eisuke and Nelson, Geoffrey M. and Sheng, Ming and Laurent, Patrick and Fenk, Lorenz A. and Butcher, Rebecca A. and Hegde, Ramanujan S. and de Bono, Mario}, issn = {0028-0836}, journal = {Nature}, number = {7639}, pages = {43--48}, publisher = {Springer Nature}, title = {{IL-17 is a neuromodulator of Caenorhabditis elegans sensory responses}}, doi = {10.1038/nature20818}, volume = {542}, year = {2017}, } @inbook{634, abstract = {As autism spectrum disorder (ASD) is largely regarded as a neurodevelopmental condition, long-time consensus was that its hallmark features are irreversible. However, several studies from recent years using defined mouse models of ASD have provided clear evidence that in mice neurobiological and behavioural alterations can be ameliorated or even reversed by genetic restoration or pharmacological treatment either before or after symptom onset. Here, we review findings on genetic and pharmacological reversibility of phenotypes in mouse models of ASD. Our review should give a comprehensive overview on both aspects and encourage future studies to better understand the underlying molecular mechanisms that might be translatable from animals to humans.}, author = {Schroeder, Jan and Deliu, Elena and Novarino, Gaia and Schmeisser, Michael}, booktitle = {Translational Anatomy and Cell Biology of Autism Spectrum Disorder}, editor = {Schmeisser, Michael and Boekers, Tobias}, pages = {189 -- 211}, publisher = {Springer}, title = {{Genetic and pharmacological reversibility of phenotypes in mouse models of autism spectrum disorder}}, doi = {10.1007/978-3-319-52498-6_10}, volume = {224}, year = {2017}, } @inproceedings{636, abstract = {Signal regular expressions can specify sequential properties of real-valued signals based on threshold conditions, regular operations, and duration constraints. In this paper we endow them with a quantitative semantics which indicates how robustly a signal matches or does not match a given expression. First, we show that this semantics is a safe approximation of a distance between the signal and the language defined by the expression. Then, we consider the robust matching problem, that is, computing the quantitative semantics of every segment of a given signal relative to an expression. We present an algorithm that solves this problem for piecewise-constant and piecewise-linear signals and show that for such signals the robustness map is a piecewise-linear function. The availability of an indicator describing how robustly a signal segment matches some regular pattern provides a general framework for quantitative monitoring of cyber-physical systems.}, author = {Bakhirkin, Alexey and Ferrere, Thomas and Maler, Oded and Ulus, Dogan}, editor = {Abate, Alessandro and Geeraerts, Gilles}, isbn = {978-331965764-6}, location = {Berlin, Germany}, pages = {189 -- 206}, publisher = {Springer}, title = {{On the quantitative semantics of regular expressions over real-valued signals}}, doi = {10.1007/978-3-319-65765-3_11}, volume = {10419}, year = {2017}, } @article{1073, abstract = {Let X and Y be finite simplicial sets (e.g. finite simplicial complexes), both equipped with a free simplicial action of a finite group G. Assuming that Y is d-connected and dimX≤2d, for some d≥1, we provide an algorithm that computes the set of all equivariant homotopy classes of equivariant continuous maps |X|→|Y|; the existence of such a map can be decided even for dimX≤2d+1. This yields the first algorithm for deciding topological embeddability of a k-dimensional finite simplicial complex into Rn under the condition k≤23n−1. More generally, we present an algorithm that, given a lifting-extension problem satisfying an appropriate stability assumption, computes the set of all homotopy classes of solutions. This result is new even in the non-equivariant situation.}, author = {Čadek, Martin and Krcál, Marek and Vokřínek, Lukáš}, issn = {01795376}, journal = {Discrete & Computational Geometry}, number = {4}, pages = {915 -- 965}, publisher = {Springer}, title = {{Algorithmic solvability of the lifting extension problem}}, doi = {10.1007/s00454-016-9855-6}, volume = {54}, year = {2017}, } @inbook{424, abstract = {We show that very weak topological assumptions are enough to ensure the existence of a Helly-type theorem. More precisely, we show that for any non-negative integers b and d there exists an integer h(b, d) such that the following holds. If F is a finite family of subsets of Rd such that βi(∩G)≤b for any G⊊F and every 0 ≤ i ≤ [d/2]-1 then F has Helly number at most h(b, d). Here βi denotes the reduced Z2-Betti numbers (with singular homology). These topological conditions are sharp: not controlling any of these [d/2] first Betti numbers allow for families with unbounded Helly number. Our proofs combine homological non-embeddability results with a Ramsey-based approach to build, given an arbitrary simplicial complex K, some well-behaved chain map C*(K)→C*(Rd).}, author = {Goaoc, Xavier and Paták, Pavel and Patakova, Zuzana and Tancer, Martin and Wagner, Uli}, booktitle = {A Journey through Discrete Mathematics: A Tribute to Jiri Matousek}, editor = {Loebl, Martin and Nešetřil, Jaroslav and Thomas, Robin}, isbn = {978-331944479-6}, pages = {407 -- 447}, publisher = {Springer}, title = {{Bounding helly numbers via betti numbers}}, doi = {10.1007/978-3-319-44479-6_17}, year = {2017}, } @article{17696, abstract = {We utilize cosmological hydrodynamic simulations to study the formation of Population III (Pop III) stars in dark matter halos exposed to strong ionizing radiation. We simulate the formation of three halos subjected to a wide range of ionizing fluxes, and find that for high flux, ionization and photoheating can delay gas collapse and star formation up to halo masses significantly larger than the atomic cooling threshold. The threshold halo mass at which gas first collapses and cools increases with ionizing flux for intermediate values, and saturates at a value approximately an order of magnitude above the atomic cooling threshold for extremely high flux (e.g. ≈5×108 M⊙ at z≈6). This behavior can be understood in terms of photoheating, ionization/recombination, and Lyα cooling in the pressure-supported, self-shielded gas core at the center of the growing dark matter halo. We examine the spherically-averaged radial velocity profiles of collapsing gas and find that a gas mass of up to ≈106 M⊙ can reach the central regions within 3 Myr, providing an upper limit on the amount of massive Pop III stars that can form. The ionizing radiation increases this limit by a factor of a few compared to strong Lyman-Werner (LW) radiation alone. We conclude that the bright HeII 1640 Å emission recently observed from the high-redshift galaxy CR7 cannot be explained by Pop III stars alone. However, in some halos, a sufficient number of Pop III stars may form to be detectable with future telescopes such as the James Webb Space Telescope (JWST).}, author = {Visbal, Eli and Bryan, Greg L. and Haiman, Zoltán}, issn = {0035-8711}, journal = {Monthly Notices of the Royal Astronomical Society}, number = {2}, pages = {1456--1465}, publisher = {Oxford University Press}, title = {{What is the maximum mass of a Population III galaxy?}}, doi = {10.1093/mnras/stx909}, volume = {469}, year = {2017}, } @article{17698, abstract = {Gaseous circumbinary accretion discs provide a promising mechanism to facilitate the mergers of supermassive black holes (SMBHs) in galactic nuclei. We measure the torques exerted on accreting SMBH binaries, using 2D, isothermal, moving-mesh, viscous hydrodynamical simulations of circumbinary accretion discs. Our computational domain includes the entire inner region of the circumbinary disk with the individual black holes (BHs) included as point masses on the grid and a sink prescription to model accretion onto each BH. The BHs each acquire their own well-resolved accretion discs ("minidiscs"). We explore a range of mass removal rates for the sink prescription removing gas from the central regions of the minidiscs. We find that the torque exerted on the binary is primarily gravitational, and dominated by the gas orbiting close behind and ahead of the individual BHs. The torques from the distorted circumbinary disc farther out and from the direct accretion of angular momentum are subdominant. The torques are sensitive to the sink prescription: slower sinks result in more gas accumulating near the BHs and more negative torques, driving the binary to merger more rapidly. For faster sinks, the torques are less negative and eventually turn positive (for unphysically fast sinks). When the minidiscs are modeled as standard alpha discs, our results are insensitive to the choice of sink radius. Scaling the simulations to a binary orbital period tbin = 1yr and background disc accretion rate Mdot = 0.3MEdd in Eddington units, the binary inspirals on a timescale of 3X10^6 years, irrespective of the SMBH masses. For binaries with total mass <10^7Msun, this is shorter than the inspiral time due to gravitational wave (GW) emission alone, implying that gas discs will have a significant impact on the SMBH binary population and can affect the GW signal for Pulsar Timing Arrays.}, author = {Tang, Yike and MacFadyen, Andrew and Haiman, Zoltán}, issn = {0035-8711}, journal = {Monthly Notices of the Royal Astronomical Society}, number = {4}, pages = {4258--4267}, publisher = {Oxford University Press}, title = {{On the orbital evolution of supermassive black hole binaries with circumbinary accretion discs}}, doi = {10.1093/mnras/stx1130}, volume = {469}, year = {2017}, } @article{17949, abstract = {Single-molecule electronic devices provide researchers with an unprecedented ability to relate novel physical phenomena to molecular chemical structures. Typically, conjugated aromatic molecular backbones are relied upon to create electronic devices, where the aromaticity of the building blocks is used to enhance conductivity. We capitalize on the classical physical organic chemistry concept of Hückel antiaromaticity by demonstrating a single-molecule switch that exhibits low conductance in the neutral state and, upon electrochemical oxidation, reversibly switches to an antiaromatic high-conducting structure. We form single-molecule devices using the scanning tunneling microscope–based break-junction technique and observe an on/off ratio of ~70 for a thiophenylidene derivative that switches to an antiaromatic state with 6-4-6-π electrons. Through supporting nuclear magnetic resonance measurements, we show that the doubly oxidized core has antiaromatic character and we use density functional theory calculations to rationalize the origin of the high-conductance state for the oxidized single-molecule junction. Together, our work demonstrates how the concept of antiaromaticity can be exploited to create single-molecule devices that are highly conducting.}, author = {Yin, Xiaodong and Zang, Yaping and Zhu, Liangliang and Low, Jonathan Z. and Liu, Zhen-Fei and Cui, Jing and Neaton, Jeffrey B. and Venkataraman, Latha and Campos, Luis M.}, issn = {2375-2548}, journal = {Science Advances}, number = {10}, publisher = {American Association for the Advancement of Science}, title = {{A reversible single-molecule switch based on activated antiaromaticity}}, doi = {10.1126/sciadv.aao2615}, volume = {3}, year = {2017}, } @article{7725, abstract = {Phenotypic plasticity is the ability of an individual genotype to alter aspects of its phenotype depending on the current environment. It is central to the persistence, resistance and resilience of populations facing variation in physical or biological factors. Genetic variation in plasticity is pervasive, which suggests its local adaptation is plausible. Existing studies on the adaptation of plasticity typically focus on single traits and a few populations, while theory about interactions among genes (for example, pleiotropy) suggests that a multi-trait, landscape scale (for example, multiple populations) perspective is required. We present data from a landscape scale, replicated, multi-trait experiment using a classic predator–prey system centred on the water flea Daphnia pulex. We find predator regime-driven differences in genetic variation of multivariate plasticity. These differences are associated with strong divergent selection linked to a predation regime. Our findings are evidence for local adaptation of plasticity, suggesting that responses of populations to environmental variation depend on the conditions in which they evolved in the past.}, author = {Reger, Julia and Lind, Martin I. and Robinson, Matthew Richard and Beckerman, Andrew P.}, issn = {2397-334X}, journal = {Nature Ecology & Evolution}, pages = {100--107}, publisher = {Springer Nature}, title = {{Predation drives local adaptation of phenotypic plasticity}}, doi = {10.1038/s41559-017-0373-6}, volume = {2}, year = {2017}, } @inproceedings{8306, abstract = {Bias-resistant public randomness is a critical component in many (distributed) protocols. Generating public randomness is hard, however, because active adversaries may behave dishonestly to bias public random choices toward their advantage. Existing solutions do not scale to hundreds or thousands of participants, as is needed in many decentralized systems. We propose two large-scale distributed protocols, RandHound and RandHerd, which provide publicly-verifiable, unpredictable, and unbiasable randomness against Byzantine adversaries. RandHound relies on an untrusted client to divide a set of randomness servers into groups for scalability, and it depends on the pigeonhole principle to ensure output integrity, even for non-random, adversarial group choices. RandHerd implements an efficient, decentralized randomness beacon. RandHerd is structurally similar to a BFT protocol, but uses RandHound in a one-time setup to arrange participants into verifiably unbiased random secret-sharing groups, which then repeatedly produce random output at predefined intervals. Our prototype demonstrates that RandHound and RandHerd achieve good performance across hundreds of participants while retaining a low failure probability by properly selecting protocol parameters, such as a group size and secret-sharing threshold. For example, when sharding 512 nodes into groups of 32, our experiments show that RandHound can produce fresh random output after 240 seconds. RandHerd, after a setup phase of 260 seconds, is able to generate fresh random output in intervals of approximately 6 seconds. For this configuration, both protocols operate at a failure probability of at most 0.08% against a Byzantine adversary.}, author = {Syta, E. and Jovanovic, P. and Kokoris Kogias, Eleftherios and Gailly, N. and Gasser, L. and Khoffi, I. and Fischer, M. J. and Ford, B.}, booktitle = {2017 IEEE Symposium on Security and Privacy}, isbn = {9781509055340}, issn = {2375-1207}, location = {San Jose, CA, United States}, pages = {444--460}, publisher = {IEEE}, title = {{Scalable bias-resistant distributed randomness}}, doi = {10.1109/SP.2017.45}, year = {2017}, } @article{644, abstract = {An instance of the valued constraint satisfaction problem (VCSP) is given by a finite set of variables, a finite domain of labels, and a sum of functions, each function depending on a subset of the variables. Each function can take finite values specifying costs of assignments of labels to its variables or the infinite value, which indicates an infeasible assignment. The goal is to find an assignment of labels to the variables that minimizes the sum. We study, assuming that P 6= NP, how the complexity of this very general problem depends on the set of functions allowed in the instances, the so-called constraint language. The case when all allowed functions take values in f0;1g corresponds to ordinary CSPs, where one deals only with the feasibility issue, and there is no optimization. This case is the subject of the algebraic CSP dichotomy conjecture predicting for which constraint languages CSPs are tractable (i.e., solvable in polynomial time) and for which they are NP-hard. The case when all allowed functions take only finite values corresponds to a finitevalued CSP, where the feasibility aspect is trivial and one deals only with the optimization issue. The complexity of finite-valued CSPs was fully classified by Thapper and Živný. An algebraic necessary condition for tractability of a general-valued CSP with a fixed constraint language was recently given by Kozik and Ochremiak. As our main result, we prove that if a constraint language satisfies this algebraic necessary condition, and the feasibility CSP (i.e., the problem of deciding whether a given instance has a feasible solution) corresponding to the VCSP with this language is tractable, then the VCSP is tractable. The algorithm is a simple combination of the assumed algorithm for the feasibility CSP and the standard LP relaxation. As a corollary, we obtain that a dichotomy for ordinary CSPs would imply a dichotomy for general-valued CSPs.}, author = {Kolmogorov, Vladimir and Krokhin, Andrei and Rolinek, Michal}, journal = {SIAM Journal on Computing}, number = {3}, pages = {1087 -- 1110}, publisher = {SIAM}, title = {{The complexity of general-valued CSPs}}, doi = {10.1137/16M1091836}, volume = {46}, year = {2017}, } @inproceedings{647, abstract = {Despite researchers’ efforts in the last couple of decades, reachability analysis is still a challenging problem even for linear hybrid systems. Among the existing approaches, the most practical ones are mainly based on bounded-time reachable set over-approximations. For the purpose of unbounded-time analysis, one important strategy is to abstract the original system and find an invariant for the abstraction. In this paper, we propose an approach to constructing a new kind of abstraction called conic abstraction for affine hybrid systems, and to computing reachable sets based on this abstraction. The essential feature of a conic abstraction is that it partitions the state space of a system into a set of convex polyhedral cones which is derived from a uniform conic partition of the derivative space. Such a set of polyhedral cones is able to cut all trajectories of the system into almost straight segments so that every segment of a reach pipe in a polyhedral cone tends to be straight as well, and hence can be over-approximated tightly by polyhedra using similar techniques as HyTech or PHAVer. In particular, for diagonalizable affine systems, our approach can guarantee to find an invariant for unbounded reachable sets, which is beyond the capability of bounded-time reachability analysis tools. We implemented the approach in a tool and experiments on benchmarks show that our approach is more powerful than SpaceEx and PHAVer in dealing with diagonalizable systems.}, author = {Bogomolov, Sergiy and Giacobbe, Mirco and Henzinger, Thomas A and Kong, Hui}, isbn = {978-331965764-6}, location = {Berlin, Germany}, pages = {116 -- 132}, publisher = {Springer}, title = {{Conic abstractions for hybrid systems}}, doi = {10.1007/978-3-319-65765-3_7}, volume = {10419 }, year = {2017}, } @article{674, abstract = {Navigation of cells along gradients of guidance cues is a determining step in many developmental and immunological processes. Gradients can either be soluble or immobilized to tissues as demonstrated for the haptotactic migration of dendritic cells (DCs) toward higher concentrations of immobilized chemokine CCL21. To elucidate how gradient characteristics govern cellular response patterns, we here introduce an in vitro system allowing to track migratory responses of DCs to precisely controlled immobilized gradients of CCL21. We find that haptotactic sensing depends on the absolute CCL21 concentration and local steepness of the gradient, consistent with a scenario where DC directionality is governed by the signal-to-noise ratio of CCL21 binding to the receptor CCR7. We find that the conditions for optimal DC guidance are perfectly provided by the CCL21 gradients we measure in vivo. Furthermore, we find that CCR7 signal termination by the G-protein-coupled receptor kinase 6 (GRK6) is crucial for haptotactic but dispensable for chemotactic CCL21 gradient sensing in vitro and confirm those observations in vivo. These findings suggest that stable, tissue-bound CCL21 gradients as sustainable “roads” ensure optimal guidance in vivo.}, author = {Schwarz, Jan and Bierbaum, Veronika and Vaahtomeri, Kari and Hauschild, Robert and Brown, Markus and De Vries, Ingrid and Leithner, Alexander F and Reversat, Anne and Merrin, Jack and Tarrant, Teresa and Bollenbach, Tobias and Sixt, Michael K}, issn = {09609822}, journal = {Current Biology}, number = {9}, pages = {1314 -- 1325}, publisher = {Cell Press}, title = {{Dendritic cells interpret haptotactic chemokine gradients in a manner governed by signal to noise ratio and dependent on GRK6}}, doi = {10.1016/j.cub.2017.04.004}, volume = {27}, year = {2017}, } @article{7064, abstract = {The complex antiferromagnetic orders observed in the honeycomb iridates are a double-edged sword in the search for a quantum spin-liquid: both attesting that the magnetic interactions provide many of the necessary ingredients, while simultaneously impeding access. Focus has naturally been drawn to the unusual magnetic orders that hint at the underlying spin correlations. However, the study of any particular broken symmetry state generally provides little clue about the possibility of other nearby ground states. Here we use magnetic fields approaching 100 Tesla to reveal the extent of the spin correlations in γ-lithium iridate. We find that a small component of field along the magnetic easy-axis melts long-range order, revealing a bistable, strongly correlated spin state. Far from the usual destruction of antiferromagnetism via spin polarization, the high-field state possesses only a small fraction of the total iridium moment, without evidence for long-range order up to the highest attainable magnetic fields.}, author = {Modic, Kimberly A and Ramshaw, B. J. and Betts, J. B. and Breznay, Nicholas P. and Analytis, James G. and McDonald, Ross D. and Shekhter, Arkady}, issn = {2041-1723}, journal = {Nature Communications}, number = {1}, publisher = {Springer Nature}, title = {{Robust spin correlations at high magnetic fields in the harmonic honeycomb iridates}}, doi = {10.1038/s41467-017-00264-6}, volume = {8}, year = {2017}, } @article{743, abstract = {This special issue of the Journal on Formal Methods in System Design is dedicated to Prof. Helmut Veith, who unexpectedly passed away in March 2016. Helmut Veith was a brilliant researcher, inspiring collaborator, passionate mentor, generous friend, and valued member of the formal methods community. Helmut was not only known for his numerous and influential contributions in the field of automated verification (most prominently his work on Counterexample-Guided Abstraction Refinement [1,2]), but also for his untiring and passionate efforts for the logic community: he co-organized the Vienna Summer of Logic (an event comprising twelve conferences and numerous workshops which attracted thousands of researchers from all over the world), he initiated the Vienna Center for Logic and Algorithms (which promotes international collaboration on logic and algorithms and organizes outreach events such as the LogicLounge), and he coordinated the Doctoral Program on Logical Methods in Computer Science at TU Wien (currently educating more than 40 doctoral students) and a National Research Network on Rigorous Systems Engineering (uniting fifteen researchers in Austria to address the challenge of building reliable and safe computer systems). With his enthusiasm and commitment, Helmut completely reshaped the Austrian research landscape in the field of logic and verification in his few years as a full professor at TU Wien.}, author = {Gottlob, Georg and Henzinger, Thomas A and Weißenbacher, Georg}, journal = {Formal Methods in System Design}, number = {2}, pages = {267 -- 269}, publisher = {Springer}, title = {{Preface of the special issue in memoriam Helmut Veith}}, doi = {10.1007/s10703-017-0307-6}, volume = {51}, year = {2017}, } @article{751, abstract = {The basement membrane (BM) is a thin layer of extracellular matrix (ECM) beneath nearly all epithelial cell types that is critical for cellular and tissue function. It is composed of numerous components conserved among all bilaterians [1]; however, it is unknown how all of these components are generated and subsequently constructed to form a fully mature BM in the living animal. Although BM formation is thought to simply involve a process of self-assembly [2], this concept suffers from a number of logistical issues when considering its construction in vivo. First, incorporation of BM components appears to be hierarchical [3-5], yet it is unclear whether their production during embryogenesis must also be regulated in a temporal fashion. Second, many BM proteins are produced not only by the cells residing on the BM but also by surrounding cell types [6-9], and it is unclear how large, possibly insoluble protein complexes [10] are delivered into the matrix. Here we exploit our ability to live image and genetically dissect de novo BM formation during Drosophila development. This reveals that there is a temporal hierarchy of BM protein production that is essential for proper component incorporation. Furthermore, we show that BM components require secretion by migrating macrophages (hemocytes) during their developmental dispersal, which is critical for embryogenesis. Indeed, hemocyte migration is essential to deliver a subset of ECM components evenly throughout the embryo. This reveals that de novo BM construction requires a combination of both production and distribution logistics allowing for the timely delivery of core components.}, author = {Matsubayashi, Yutaka and Louani, Adam and Dragu, Anca and Sanchez Sanchez, Besaiz and Serna Morales, Eduardo and Yolland, Lawrence and György, Attila and Vizcay, Gema and Fleck, Roland and Heddleston, John and Chew, Teng and Siekhaus, Daria E and Stramer, Brian}, issn = {09609822}, journal = {Current Biology}, number = {22}, pages = {3526 -- 3534e.4}, publisher = {Cell Press}, title = {{A moving source of matrix components is essential for De Novo basement membrane formation}}, doi = {10.1016/j.cub.2017.10.001}, volume = {27}, year = {2017}, }