Visual Landmark Recognition from Internet Photo Collections: A Large-Scale Evaluation

The task of a visual landmark recognition system is to identify photographed buildings or objects in query photos and to provide the user with relevant information on them. With their increasing coverage of the world's landmark buildings and objects, Internet photo collections are now being used as a source for building such systems in a fully automatic fashion. This process typically consists of three steps: clustering large amounts of images by the objects they depict; determining object names from user-provided tags; and building a robust, compact, and efficient recognition index. To this date, however, there is little empirical information on how well current approaches for those steps perform in a large-scale open-set mining and recognition task. Furthermore, there is little empirical information on how recognition performance varies for different types of landmark objects and where there is still potential for improvement. With this paper, we intend to fill these gaps. Using a dataset of 500k images from Paris, we analyze each component of the landmark recognition pipeline in order to answer the following questions: How many and what kinds of objects can be discovered automatically? How can we best use the resulting image clusters to recognize the object in a query? How can the object be efficiently represented in memory for recognition? How reliably can semantic information be extracted? And finally: What are the limiting factors in the resulting pipeline from query to semantics? We evaluate how different choices of methods and parameters for the individual pipeline steps affect overall system performance and examine their effects for different query categories such as buildings, paintings or sculptures

Dispersion relations for η′→ηππ\eta'\to\eta\pi\pi

We present a dispersive analysis of the decay amplitude for $\eta'\to\eta\pi\pi$ that is based on the fundamental principles of analyticity and unitarity. In this framework, final-state interactions are fully taken into account. Our dispersive representation relies only on input for the $\pi\pi$ and $\pi\eta$ scattering phase shifts. Isospin symmetry allows us to describe both the charged and neutral decay channel in terms of the same function. The dispersion relation contains subtraction constants that cannot be fixed by unitarity. We determine these parameters by a fit to Dalitz-plot data from the VES and BES-III experiments. We study the prediction of a low-energy theorem and compare the dispersive fit to variants of chiral perturbation theory.Comment: 22 pages, 10 figures; v2: added footnote, version published in EPJ

Lattice Design and Dynamic Aperture Studies for the FCC-ee Top-Up Booster Synchrotron

The Future Circular Collider (FCC) study investigates the feasibility of circular colliders in the post-LHC era. The sub-study FCC-ee is a 100 km electron positron collider in the energy range of 90-365 GeV. In order to achieve a design luminosity in the order of 1036cm−2s−1 continuous top-up injection is required. The injector chain therefore includes a 100 km booster synchrotron in the same tunnel as the collider rings. This paper presents the lattice design of this booster synchrotron and the first dynamic aperture studies based on the chromaticity correction sextupole scheme

Lattice Design and Dynamic Aperture Studies for the FCC-ee Top-Up Booster Synchrotron

The Future Circular Collider (FCC) study investigates the feasibility of circular colliders in the post-LHC era. The sub-study FCC-ee is a 100 km electron positron collider in the energy range of 90-365 GeV. In order to achieve a design luminosity in the order of 1036cm−2s−1 continuous top-up injection is required. The injector chain therefore includes a 100 km booster synchrotron in the same tunnel as the collider rings. This paper presents the lattice design of this booster synchrotron and the first dynamic aperture studies based on the chromaticity correction sextupole scheme

Towards a Unified Quark-Hadron Matter Equation of State for Applications in Astrophysics and Heavy-Ion Collisions

We outline an approach to a unified equation of state for quark-hadron matter on the basis of a $\Phi-$derivable approach to the generalized Beth-Uhlenbeck equation of state for a cluster decomposition of thermodynamic quantities like the density. To this end we summarize the cluster virial expansion for nuclear matter and demonstrate the equivalence of the Green's function approach and the $\Phi-$derivable formulation. For an example, the formation and dissociation of deuterons in nuclear matter is discussed. We formulate the cluster $\Phi-$derivable approach to quark-hadron matter which allows to take into account the specifics of chiral symmetry restoration and deconfinement in triggering the Mott-dissociation of hadrons. This approach unifies the description of a strongly coupled quark-gluon plasma with that of a medium-modified hadron resonance gas description which are contained as limiting cases. The developed formalism shall replace the common two-phase approach to the description of the deconfinement and chiral phase transition that requires a phase transition construction between separately developed equations of state for hadronic and quark matter phases. Applications to the phenomenology of heavy-ion collisions and astrophysics are outlined.Comment: 35 pages, 3 figures, Special Issue "Compact Stars in the QCD Phase Diagram

Control of reactive intermediates in enzymes and enzyme complexes

Enzymes are the catalysts of life. They accelerate the rate of chemical reactions that would otherwise take longer than an organism’s lifetime to take just millisecond. To achieve these remarkable rate enhancements enzymes arrange into a three dimensional fold that places its amino acids in a way, which binds the transition state of the reaction better than the substrates and products of the reaction, thereby lowering the activation energy of the reaction. Enzymes are also very specific and often only catalyze one specific chemical transformation without producing side products. They are able to achieve all this under ambient temperatures and in cells that contain over 2700 different metabolites. In this work we focus on the mechanisms enzyme use to control reactive intermediates both inside their active site and between enzymes of a metabolic pathway to avoid the formation of deleterious side products. In the first part we investigate the catalytic cycle of NAD(P)H dependent oxidoreductases. We show that the two enoyl-thioester reductases; Etr1p from Candida tropicalis of the MDR enzyme superfamily and InhA from Mycobacterium tuberculosis of the SDR enzyme superfamily form a covalent adduct between substrate and the C2 carbon of the cofactor. The observation of this reactive intermediate at the active site of enzymes from the two largest NAD(P)H dependent oxidoreductase superfamilies not only calls for a careful reconsideration of the canonical reaction mechanism of these enzymes, but also sets the basis for the development of novel tools to study, manipulate and inhibit their catalytic cycle. We demonstrate this by successfully changing the protonation specificity of Etr1p from re- to si- face. Using the molecular probe we show that a conserved threonine at the active site of Etr1p is mainly responsible for preventing the formation of a toxic side product and not for the stabilization of the wanted transition state along the reaction coordinate. This effect of destabilization of unwanted transition states, often termed ´negative catalysis´, poses a complementary mechanism of reaction control to the canonical transition state theory and is discussed in detail in this work. In the second part of this thesis we take a look at two enzyme complexes and the strategies they use to control the transfer of a reactive intermediate from one active site to the next one. The trifunctional propionyl-CoA synthase forms a closed reaction chamber to sequester the reactive acrylyl-CoA intermediate. This reaction chamber encloses all three active sites of the enzyme fusion protein, but does not show the directionality of a conventional tunnel, and the CoA ester intermediates are not covalently attached to the enzyme but freely diffuse within the compartment. The substrate channeling mechanism of the thiolase/HMG-CoA synthase complex of archaea most closely resembles the covalent swinging arm fatty acid and polyketide synthases use to channel their intermediates. In the thiolase/HMG-CoA synthase complex the intermediate is however not covalently attached, but instead tightly bound in a shared CoA binding site, enabling the pantothenyl-arm of CoA to swing from the thiolase active site to the HMG-CoA synthase active site. The two channeling systems we describe in this work therefore represent two alternative ways of channeling CoA ester intermediates in a non-covalent fashion

Entanglement Witnesses for Graph States: General Theory and Examples

We present a general theory for the construction of witnesses that detect genuine multipartite entanglement in graph states. First, we present explicit witnesses for all graph states of up to six qubits which are better than all criteria so far. Therefore, lower fidelities are required in experiments that aim at the preparation of graph states. Building on these results, we develop analytical methods to construct two different types of entanglement witnesses for general graph states. For many classes of states, these operators exhibit white noise tolerances that converge to one when increasing the number of particles. We illustrate our approach for states such as the linear and the 2D cluster state. Finally, we study an entanglement monotone motivated by our approach for graph states.Comment: 12 pages + appendix, 7 figure

Tropospheric Aqueous-Phase Oxidation of Isoprene-Derived Dihydroxycarbonyl Compounds

The dihydroxycarbonyls 3,4-dihydroxy-2-butanone (DHBO) and 2,3-dihydroxy-2-methylpropanal (DHMP) formed from isoprene oxidation products in the atmospheric gas phase under low-NO conditions can be expected to form aqSOA in the tropospheric aqueous phase because of their solubility. In the present study, DHBO and DHMP were investigated concerning their radical-driven aqueous-phase oxidation reaction kinetics. For DHBO and DHMP the following rate constants at 298 K are reported: k(OH + DHBO) = (1.0 ± 0.1) × 109 L mol-1 s-1, k(NO3 + DHBO) = (2.6 ± 1.6) × 106 L mol-1 s-1, k(SO4-+ DHBO) = (2.3 ± 0.2) × 107 L mol-1 s-1, k(OH + DHMP) = (1.2 ± 0.1) × 109 L mol-1 s-1, k (NO3 + DHMP) = (7.9 ± 0.7) × 106 L mol-1 s-1, k(SO4- + DHMP) = (3.3 ± 0.2) × 107 L mol-1 s-1, together with their respective temperature dependences. The product studies of both DHBO and DHMP revealed hydroxydicarbonyls, short chain carbonyls, and carboxylic acids, such as hydroxyacetone, methylglyoxal, and lactic and pyruvic acid as oxidation products with single yields up to 25%. The achieved carbon balance was 75% for DHBO and 67% for DHMP. An aqueous-phase oxidation scheme for both DHBO and DHMP was developed on the basis of the experimental findings to show their potential to contribute to the aqSOA formation. It can be expected that the main contribution to aqSOA occurs via acid formation while other short-chain oxidation products are expected to back-partition into the gas phase to undergo further oxidation there