TY - JOUR
AB - Understanding patterns and correlates of local adaptation in heterogeneous landscapes can provide important information in the selection of appropriate seed sources for restoration. We assessed the extent of local adaptation of fitness components in 12 population pairs of the perennial herb Rutidosis leptorrhynchoides (Asteraceae) and examined whether spatial scale (0.7-600 km), environmental distance, quantitative (QST) and neutral (FST) genetic differentiation, and size of the local and foreign populations could predict patterns of adaptive differentiation. Local adaptation varied among populations and fitness components. Including all population pairs, local adaptation was observed for seedling survival, but not for biomass, while foreign genotype advantage was observed for reproduction (number of inflorescences). Among population pairs, local adaptation increased with QST and local population size for biomass. QST was associated with environmental distance, suggesting ecological selection for phenotypic divergence. However, low FST and variation in population structure in small populations demonstrates the interaction of gene flow and drift in constraining local adaptation in R. leptorrhynchoides. Our study indicates that for species in heterogeneous landscapes, collecting seed from large populations from similar environments to candidate sites is likely to provide the most appropriate seed sources for restoration.
AU - Pickup, Melinda
AU - Field, David
AU - Rowell, David
AU - Young, Andrew
ID - 498
IS - 8
JF - Evolutionary Applications
TI - Predicting local adaptation in fragmented plant populations: Implications for restoration genetics
VL - 5
ER -
TY - JOUR
AU - Sixt, Michael K
ID - 506
IS - 3
JF - Journal of Cell Biology
TI - Cell migration: Fibroblasts find a new way to get ahead
VL - 197
ER -
TY - GEN
AB - Two-player games on graphs are central in many problems in formal verification and program analysis such as synthesis and verification of open systems. In this work we consider solving recursive game graphs (or pushdown game graphs) that can model the control flow of sequential programs with recursion. While pushdown games have been studied before with qualitative objectives, such as reachability and ω-regular objectives, in this work we study for the first time such games with the most well-studied quantitative objective, namely, mean-payoff objectives. In pushdown games two types of strategies are relevant: (1) global strategies, that depend on the entire global history; and (2) modular strategies, that have only local memory and thus do not depend on the context of invocation, but only on the history of the current invocation of the module. Our main results are as follows: (1) One-player pushdown games with mean-payoff objectives under global strategies are decidable in polynomial time. (2) Two- player pushdown games with mean-payoff objectives under global strategies are undecidable. (3) One-player pushdown games with mean-payoff objectives under modular strategies are NP- hard. (4) Two-player pushdown games with mean-payoff objectives under modular strategies can be solved in NP (i.e., both one-player and two-player pushdown games with mean-payoff objectives under modular strategies are NP-complete). We also establish the optimal strategy complexity showing that global strategies for mean-payoff objectives require infinite memory even in one-player pushdown games; and memoryless modular strategies are sufficient in two- player pushdown games. Finally we also show that all the problems have the same complexity if the stack boundedness condition is added, where along with the mean-payoff objective the player must also ensure that the stack height is bounded.
AU - Chatterjee, Krishnendu
AU - Velner, Yaron
ID - 5377
SN - 2664-1690
TI - Mean-payoff pushdown games
ER -
TY - GEN
AB - One central issue in the formal design and analysis of reactive systems is the notion of refinement that asks whether all behaviors of the implementation is allowed by the specification. The local interpretation of behavior leads to the notion of simulation. Alternating transition systems (ATSs) provide a general model for composite reactive systems, and the simulation relation for ATSs is known as alternating simulation. The simulation relation for fair transition systems is called fair simulation. In this work our main contributions are as follows: (1) We present an improved algorithm for fair simulation with Büchi fairness constraints; our algorithm requires O(n3 · m) time as compared to the previous known O(n6)-time algorithm, where n is the number of states and m is the number of transitions. (2) We present a game based algorithm for alternating simulation that requires O(m2)-time as compared to the previous known O((n · m)2)-time algorithm, where n is the number of states and m is the size of transition relation. (3) We present an iterative algorithm for alternating simulation that matches the time complexity of the game based algorithm, but is more space efficient than the game based algorithm.
AU - Chatterjee, Krishnendu
AU - Chaubal, Siddhesh
AU - Kamath, Pritish
ID - 5378
SN - 2664-1690
TI - Faster algorithms for alternating refinement relations
ER -
TY - GEN
AB - We consider the problem of inference in agraphical model with binary variables. While in theory it is arguably preferable to compute marginal probabilities, in practice researchers often use MAP inference due to the availability of efficient discrete optimization algorithms. We bridge the gap between the two approaches by introducing the Discrete Marginals technique in which approximate marginals are obtained by minimizing an objective function with unary and pair-wise terms over a discretized domain. This allows the use of techniques originally devel-oped for MAP-MRF inference and learning. We explore two ways to set up the objective function - by discretizing the Bethe free energy and by learning it from training data. Experimental results show that for certain types of graphs a learned function can out-perform the Bethe approximation. We also establish a link between the Bethe free energy and submodular functions.
AU - Korc, Filip
AU - Kolmogorov, Vladimir
AU - Lampert, Christoph
ID - 5396
SN - 2664-1690
TI - Approximating marginals using discrete energy minimization
ER -
TY - GEN
AB - This document is created as a part of the project “Repository for Research Data on IST Austria”. It summarises the actual state of research data at IST Austria, based on survey results. It supports the choice of appropriate software, which would best fit the requirements of their users, the researchers.
AU - Porsche, Jana
ID - 5398
TI - Actual state of research data @ ISTAustria
ER -
TY - CHAP
AU - Gupta, Ashutosh
ID - 5745
SN - 0302-9743
T2 - Automated Technology for Verification and Analysis
TI - Improved Single Pass Algorithms for Resolution Proof Reduction
VL - 7561
ER -
TY - JOUR
AB - Canny's edge detection algorithm is a classical and robust method for edge detection in gray-scale images. The two
significant features of this method are introduction of NMS (Non-Maximum Suppression) and double thresholding of
the gradient image. Due to poor illumination, the region boundaries in an image may become vague, creating
uncertainties in the gradient image. In this paper, we have proposed an algorithm based on the concept of type-2 fuzzy sets to handle uncertainties that automatically selects the threshold values needed to segment the gradient image using classical Canny’s edge detection algorithm. The results show that our algorithm works significantly well on different benchmark images as well as medical images (hand radiography images).
AU - Biswas, Ranita
AU - Sil, Jaya
ID - 5839
JF - Procedia Technology
SN - 2212-0173
TI - An Improved Canny Edge Detection Algorithm Based on Type-2 Fuzzy Sets
VL - 4
ER -
TY - JOUR
AB - The human Mediator complex controls RNA polymerase II (pol II) function in ways that remain incompletely understood. Activator-Mediator binding alters Mediator structure, and these activator-induced structural shifts appear to play key roles in regulating transcription. A recent cryo-electron microscopy (EM) analysis revealed that pol II adopted a stable orientation within a Mediator-pol II-TFIIF assembly in which Mediator was bound to the activation domain of viral protein 16 (VP16). Whereas TFIIF was shown to be important for orienting pol II within this assembly, the potential role of the activator was not assessed. To determine how activator binding might affect pol II orientation, we isolated human Mediator-pol II-TFIIF complexes in which Mediator was not bound to an activator. Cryo-EM analysis of this assembly, coupled with pol II crystal structure docking, revealed that pol II binds Mediator at the same general location; however, in contrast to VP16-bound Mediator, pol II does not appear to stably orient in the absence of an activator. Variability in pol II orientation might be important mechanistically, perhaps to enable sense and antisense transcription at human promoters. Because Mediator interacts extensively with pol II, these results suggest that Mediator structural shifts induced by activator binding help stably orient pol II prior to transcription initiation.
AU - Bernecky, Carrie A
AU - Taatjes, Dylan
ID - 596
IS - 5
JF - Journal of Molecular Biology
TI - Activator-mediator binding stabilizes RNA polymerase II orientation within the human mediator-RNA polymerase II-TFIIF assembly
VL - 417
ER -
TY - JOUR
AB - Tonic receptors convey stimulus duration and intensity and are implicated in homeostatic control. However, how tonic homeostatic signals are generated and how they reconfigure neural circuits and modify animal behavior is poorly understood. Here we show that Caenorhabditis elegans O2-sensing neurons are tonic receptors that continuously signal ambient [O2] to set the animal's behavioral state. Sustained signaling relied on a Ca2+ relay involving L-type voltage-gated Ca2+ channels, the ryanodine and the inositol-1,4,5-trisphosphate receptors. Tonic activity evoked continuous neuropeptide release, which helps elicit the enduring behavioral state associated with high [O2]. Sustained O2 receptor signaling was propagated to downstream neural circuits, including the hub interneuron RMG. O2 receptors evoked similar locomotory states at particular O2 concentrations, regardless of previous d[O2]/dt. However, a phasic component of the URX receptors' response to high d[O2]/dt, as well as tonic-to-phasic transformations in downstream interneurons, enabled transient reorientation movements shaped by d[O2]/dt. Our results highlight how tonic homeostatic signals can generate both transient and enduring behavioral change.
AU - Busch, Karl Emanuel
AU - Laurent, Patrick
AU - Soltesz, Zoltan
AU - Murphy, Robin Joseph
AU - Faivre, Olivier
AU - Hedwig, Berthold
AU - Thomas, Martin
AU - Smith, Heather L
AU - de Bono, Mario
ID - 6136
IS - 4
JF - Nature Neuroscience
SN - 1097-6256
TI - Tonic signaling from O2 sensors sets neural circuit activity and behavioral state
VL - 15
ER -
TY - JOUR
AB - First we note that the best polynomial approximation to vertical bar x vertical bar on the set, which consists of an interval on the positive half-axis and a point on the negative half-axis, can be given by means of the classical Chebyshev polynomials. Then we explore the cases when a solution of the related problem on two intervals can be given in elementary functions.
AU - Pausinger, Florian
ID - 6588
IS - 1
JF - Journal of Mathematical Physics, Analysis, Geometry
SN - 1812-9471
TI - Elementary solutions of the Bernstein problem on two intervals
VL - 8
ER -
TY - CONF
AB - This paper proposes a novel cooperative approach for two-hop amplify-and-forward (A&F) relaying that exploits both the signal forwarded by the relay and the one directly transmitted by the source in impulse-radio ultra-wideband (IR-UWB) systems. Specifically, we focus on a non-coherent setup employing a double-differential encoding scheme at the source node and a single differential demodulation at the relay and destination. The log-likelihood ratio based decision rule is derived at the destination node. A semi-analytical power allocation strategy is presented by evaluating a closed-form expression for the effective signal to noise ratio (SNR) at the destination, which is maximized by exhaustive search. Numerical simulations show that the proposed system outperforms both the direct transmission with single differential encoding and the non-cooperative multi-hop approach in different scenarios.
AU - Mondelli, Marco
AU - Zhou, Qi
AU - Ma, Xiaoli
AU - Lottici, Vincenzo
ID - 6746
SN - 1520-6149
T2 - 2012 IEEE International Conference on Acoustics, Speech and Signal Processing (ICASSP)
TI - A cooperative approach for amplify-and-forward differential transmitted reference IR-UWB relay systems
ER -
TY - JOUR
AB - The Seebeck coefficients, electrical resistivities, total thermal conductivities, and magnetization are reported for temperatures between 5 and 350 K for n-type Bi0.88Sb0.12 nano-composite alloys made by Ho-doping at the 0, 1, and 3 % atomic levels. The alloys were prepared using a dc hot-pressing method, and are shown to be single phase for both Ho contents with grain sizes on the average of 900 nm. We find the parent compound has a maximum of ZT = 0.28 at 231 K, while doping 1 % Ho increases the maximum ZT to 0.31 at 221 K and the 3 % doped sample suppresses the maximum ZT = 0.24 at a temperature of 260 K.
AU - Lukas, K. C.
AU - Joshi, G.
AU - Modic, Kimberly A
AU - Ren, Z. F.
AU - Opeil, C. P.
ID - 7074
IS - 15
JF - Journal of Materials Science
SN - 0022-2461
TI - Thermoelectric properties of Ho-doped Bi0.88Sb0.12
VL - 47
ER -
TY - CONF
AB - Software model checking, as an undecidable problem, has three possible outcomes: (1) the program satisfies the specification, (2) the program does not satisfy the specification, and (3) the model checker fails. The third outcome usually manifests itself in a space-out, time-out, or one component of the verification tool giving up; in all of these failing cases, significant computation is performed by the verification tool before the failure, but no result is reported. We propose to reformulate the model-checking problem as follows, in order to have the verification tool report a summary of the performed work even in case of failure: given a program and a specification, the model checker returns a condition Ψ - usually a state predicate - such that the program satisfies the specification under the condition Ψ - that is, as long as the program does not leave the states in which Ψ is satisfied. In our experiments, we investigated as one major application of conditional model checking the sequential combination of model checkers with information passing. We give the condition that one model checker produces, as input to a second conditional model checker, such that the verification problem for the second is restricted to the part of the state space that is not covered by the condition, i.e., the second model checker works on the problems that the first model checker could not solve. Our experiments demonstrate that repeated application of conditional model checkers, passing information from one model checker to the next, can significantly improve the verification results and performance, i.e., we can now verify programs that we could not verify before.
AU - Beyer, Dirk
AU - Henzinger, Thomas A
AU - Keremoglu, Mehmet
AU - Wendler, Philipp
ID - 1384
T2 - Proceedings of the ACM SIGSOFT 20th International Symposium on the Foundations of Software Engineering
TI - Conditional model checking: A technique to pass information between verifiers
ER -
TY - JOUR
AB - Given a possibly reducible and non-reduced spectral cover π: X → C over a smooth projective complex curve C we determine the group of connected components of the Prym variety Prym(X/C). As an immediate application we show that the finite group of n-torsion points of the Jacobian of C acts trivially on the cohomology of the twisted SL n-Higgs moduli space up to the degree which is predicted by topological mirror symmetry. In particular this yields a new proof of a result of Harder-Narasimhan, showing that this finite group acts trivially on the cohomology of the twisted SL n stable bundle moduli space.
AU - Tamas Hausel
AU - Pauly, Christian
ID - 1471
IS - 3
JF - Geometry and Topology
TI - Prym varieties of spectral covers
VL - 16
ER -
TY - JOUR
AB - For G = GL 2, PGL 2, SL 2 we prove that the perverse filtration associated with the Hitchin map on the rational cohomology of the moduli space of twisted G-Higgs bundles on a compact Riemann surface C agrees with the weight filtration on the rational cohomology of the twisted G character variety of C when the cohomologies are identified via non-Abelian Hodge theory. The proof is accomplished by means of a study of the topology of the Hitchin map over the locus of integral spectral curves.
AU - De Cataldo, Mark A
AU - Tamas Hausel
AU - Migliorini, Luca
ID - 1472
IS - 3
JF - Annals of Mathematics
TI - Topology of hitchin systems and Hodge theory of character varieties: The case A 1
VL - 175
ER -
TY - JOUR
AB - In July, 2011, a 32-year-old man presented with thoracic pain radiating to the left arm and upper dorsum, shortness of breath, and palpitations. He had had upper back tension for 6 months. Medical history was unremarkable apart from moderate nicotine use (two pack-years). Echocardiography, electrocardiography, and laboratory tests were unremarkable, excluding a cardiac event. CT of the chest after chest radiography showed a large bulla of 16 cm diameter in the right hemithorax (figure A). We did not detect radiological evidence of underlying pulmonary disease. The bulla wall was unremarkable and no structures were seen within the bulla.
AU - Erne, Barbara
AU - Graff, Mareike
AU - Klemm, Wolfram
AU - Danzl, Johann G
AU - Leschber, Gunda
ID - 1055
IS - 9849
JF - The Lancet
TI - Bulla in the lung
VL - 380
ER -
TY - JOUR
AB - We prepare and study a metastable attractive Mott-insulator state formed with bosonic atoms in a three-dimensional optical lattice. Starting from a Mott insulator with Cs atoms at weak repulsive interactions, we use a magnetic Feshbach resonance to tune the interactions to large attractive values and produce a metastable state pinned by attractive interactions with a lifetime on the order of 10 s. We probe the (de)excitation spectrum via lattice modulation spectroscopy, measuring the interaction dependence of two- and three-body bound-state energies. As a result of increased on-site three-body loss we observe resonance broadening and suppression of tunneling processes that produce three-body occupation.
AU - Mark, Manfred
AU - Haller, Elmar
AU - Lauber, Katharina
AU - Danzl, Johann G
AU - Janisch, Alexander
AU - Büchler, Hans
AU - Daley, Andrew
AU - Nägerl, Hanns
ID - 1056
IS - 21
JF - Physical Review Letters
TI - Preparation and spectroscopy of a metastable mott-insulator state with attractive interactions
VL - 108
ER -
TY - JOUR
AB - Although liquids typically flow around intruding objects, a counterintuitive phenomenon occurs in dense suspensions of micrometre-sized particles: they become liquid-like when perturbed lightly, but harden when driven strongly. Rheological experiments have investigated how such thickening arises under shear, and linked it to hydrodynamic interactions or granular dilation. However, neither of these mechanisms alone can explain the ability of suspensions to generate very large, positive normal stresses under impact. To illustrate the phenomenon, such stresses can be large enough to allow a person to run across a suspension without sinking, and far exceed the upper limit observed under shear or extension. Here we show that these stresses originate from an impact-generated solidification front that transforms an initially compressible particle matrix into a rapidly growing jammed region, ultimately leading to extraordinary amounts of momentum absorption. Using high-speed videography, embedded force sensing and X-ray imaging, we capture the detailed dynamics of this process as it decelerates a metal rod hitting a suspension of cornflour (cornstarch) in water. We develop a model for the dynamic solidification and its effect on the surrounding suspension that reproduces the observed behaviour quantitatively. Our findings suggest that prior interpretations of the impact resistance as dominated by shear thickening need to be revisited.
AU - Waitukaitis, Scott R
AU - Jaeger, Heinrich
ID - 113
IS - 7406
JF - Nature
TI - Impact-activated solidification of dense suspensions via dynamic jamming fronts
VL - 487
ER -
TY - JOUR
AB - We report on an investigation of the solidification of a cornstarch and water suspension during normal impact on its surface. We find that a finite time after impact, the suspension displays characteristics reminiscent of a solid, including localized stress transmission, the development of a yield stress, and some elastic energy storage. The time dependence of these characteristics depends on the thickness of the cornstarch layer, showing that the solidification is a dynamic process driven by the impacting object. These findings confirm previous speculations that rapidly applied normal stress transforms the normally fluid-like suspension into a temporarily jammed solid and draw a clear distinction between the effects of normal stress and shear stress in dense suspensions.
AU - Waitukaitis, Scott R
AU - Jaeger, Heinrich
ID - 114
IS - 1E
JF - Revista Cubana de Fisica
TI - Solidification of a cornstarch and water suspension
VL - 29
ER -