bluuebunny/crossref_metadata_2025 huggingface dataset:
Metallocluster transactions: dynamic protein interactions guide the biosynthesis of Fe–S clusters in bacteria
Authors: Zheng Chenkang , Dos Santos Patricia C.
Published: October 2018

Iron–sulfur (Fe–S) clusters are ubiquitous cofactors present in all domains of life. The chemistries catalyzed by these inorganic cofactors are diverse and their associated enzymes are involved in many cellular processes. Despite the wide range of structures reported for Fe–S clusters inserted into proteins, the biological synthesis of all Fe–S clusters starts with the assembly of simple units of 2Fe–2S and 4Fe–4S clusters. Several systems have been associated with the formation of Fe–S clusters in bacteria with varying phylogenetic origins and number of biosynthetic and regulatory components. All systems, however, construct Fe–S clusters through a similar biosynthetic scheme involving three main steps: (1) sulfur activation by a cysteine desulfurase, (2) cluster assembly by a scaffold protein, and (3) guided delivery of Fe–S units to either final acceptors or biosynthetic enzymes involved in the formation of complex metalloclusters. Another unifying feature on the biological formation of Fe–S clusters in bacteria is that these systems are tightly regulated by a network of protein interactions. Thus, the formation of transient protein complexes among biosynthetic components allows for the direct transfer of reactive sulfur and Fe–S intermediates preventing oxygen damage and reactions with non-physiological targets. Recent studies revealed the importance of reciprocal signature sequence motifs that enable specific protein–protein interactions and consequently guide the transactions between physiological donors and acceptors. Such findings provide insights into strategies used by bacteria to regulate the flow of reactive intermediates and provide protein barcodes to uncover yet-unidentified cellular components involved in Fe–S metabolism.
Specificity and selectivity in post-translational biotin addition
Authors: Beckett Dorothy
Published: October 2018

Biotin, which serves as a carboxyl group carrier in reactions catalyzed by biotin-dependent carboxylases, is essential for life in most organisms. To function in carboxylate transfer, the vitamin must be post-translationally linked to a specific lysine residue on the biotin carboxyl carrier (BCC) of a carboxylase in a reaction catalyzed by biotin protein ligases. Although biotin addition is highly selective for any single carboxylase substrate, observations of interspecies biotinylation suggested little discrimination among the BCCs derived from the carboxylases of a broad range of organisms. Application of single turnover kinetic techniques to measurements of post-translational biotin addition reveals previously unappreciated selectivity that may be of physiological significance.
Integrative workflows for network analysis
Authors: Khan Faiz M. , Gupta Shailendra K. , Wolkenhauer Olaf
Published: October 2018

Due to genetic heterogeneity across patients, the identification of effective disease signatures and therapeutic targets is challenging. Addressing this challenge, we have previously developed a network-based approach, which integrates heterogeneous sources of biological information to identify disease specific core-regulatory networks. In particular, our workflow uses a multi-objective optimization function to calculate a ranking score for network components (e.g. feedback/feedforward loops) based on network properties, biomedical and high-throughput expression data. High ranked network components are merged to identify the core-regulatory network(s) that is then subjected to dynamical analysis using stimulus–response and in silico perturbation experiments for the identification of disease gene signatures and therapeutic targets. In a case study, we implemented our workflow to identify bladder and breast cancer specific core-regulatory networks underlying epithelial–mesenchymal transition from the E2F1 molecular interaction map.

In this study, we review our workflow and described how it has developed over time to understand the mechanisms underlying disease progression and prediction of signatures for clinical decision making.
Amount of TNF‐α released from macrophages reacting with polyethylene particles showed dose‐dependent relationship to the total surface area of added particles
Authors: Shen Weiqi , Tomita Naohide , Niikura Miho , Sugino Takuma
Published: October 2018

The immune response to ultra‐high molecular weight polyethylene wear debris is thought to be one of the major causes of osteolysis and aseptic loosening. An in‐vitro method for the measurement of the response is necessary in order to priori estimate the lifespan of the implants. It is of importance to distinguish the bioactivity of various polyethylene biomaterials. The current research focused on the inverse culturing process, which was shown to be effective to evaluate the biological reaction of mouse macrophages and wear particles by estimating the amount of inflammatory cytokines. In this study, several improvements were carried out through trial quantification. Silicon sheet was introduced instead of PVC seal to remove air bubbles and to eliminate the influence of potentially‐attached endotoxin. Calculations along with experiments according to Stokes’ law were also performed to determine the reaction time and the minimum particle size that can be phagocytosed by macrophages in the improved method. The authors co‐incubated mouse macrophages and polyethylene particles in different sizes, densities and molecular weights using the new method. The result suggests that the amount of tumour necrosis factor‐α (TNF‐α) generated is dosage dependent on the total surface area of particles added regardless of particle size, density and molecular weight of polyethylene.
Panoramic shot device of 720‐degree VR for hexacopter UAV based on three‐axis gimbal
Authors: Xia Kun , Li Han , Li Zheng
Published: October 2018

A new structure and an improved control method of the three‐axis gimbal for hexacopter unmanned aerial vehicle (UAV) are presented. By optimising the structure of the three‐axis gimbal and establishing the mathematical model with the maximum stability, the improved structure of three‐axis gimbal is proposed, which two groups of virtual reality (VR) camera arrays are mounted on the top and bottom of the frame to meet requirements of the 720‐degree panoramic shot. The redundant design of five motors in the structure could realise the stabilisation of three‐axis linkage of the gimbal that will ensure the optimal performance of the independent stable cameras all the time. At the same time, the attitude of the gimbal could be controlled by the complementary filter and proportional, integral and derivative algorithms. Furthermore, the closed‐loop controls of angle, speed and current of Brushless DC motor are realised by the non‐contact magnetic encoder, which improves the anti‐shake performance of the system. The experiments in the prototype are designed to prove the anti‐shake performance of the proposed gimbal and stability of the hexacopter UAV.
Mask‐less oral and nasal audio recording and air flow estimation for speech analysis
Authors: Derrick D. , Duerr J. , Kerr R.G.
Published: October 2018

Here is demonstrated Rivener, a mask‐less oral and nasal audio recorder and air flow estimation system. This system records audio and low‐frequency pseudo‐sound from the nares and mouth. The system does not interfere with speech intelligibility, and minimally interferes with visual observation of the speaker. From these recordings, nasalance (a ratio of oral and nasal sound energy), oral air flow, and nasal air flow patterns may be estimated, all while allowing effective clinical observation. The first demonstration is a case‐study comparison of the difference between hearing‐impaired (HI) speech and non‐impaired (NI) speech. Rivener records standard features of HI speech such as: (i) Atypically high or low speech amplitude; (ii) fundamental frequency (pitch) making individual words into intonational phrases; (iii) speech segment substitution; (iv) hypernasalance; (v) atypical air flow in HI speech, including low air flow during plosive release. The second demonstration is a comparison of Rivener and the Rothenberg NAS‐1's ability to record nasalance among 26 New Zealand English speakers. The NAS‐1 can differentiate low, medium, and high nasalance passages, whereas Rivener differentiates only medium and high nasalance passages consistently.
SIW‐based microfluidically tunable PD with wide‐frequency‐tuning range
Authors: Chen Chang‐Ming , Yao Yao , Wang Hai‐Shi , Nie Hai
Published: October 2018

A passive microfluidically tunable power divider (PD) with a wide‐frequency‐agile range based on substrate integrated waveguide (SIW) has been presented. The proposed structure consists of two SIW resonators loaded on the same complementary split‐ring resonator and five identical filling‐water tubes placed on the top plane. By injecting water into five tubes, the effective permittivity of the substrate can be controlled, and thus the operating frequency of the PD can be precisely tuned. For demonstration, the proposed PD is designed and fabricated. The measured and simulated results are given, showing good agreement.
Four‐way hybrid SIW/microstrip‐line power divider with improved output isolation
Authors: Song Kaijun , Lu Wenzheng , Guo Song , Fan Yong
Published: October 2018

This Letter presents a four‐way hybrid substrate integrated waveguide/microstrip‐line power divider circuit based on the double microstrip‐slot coupling. By slotting between T branch and loading isolation resistance, the isolation and output voltage standing wave ratio between non‐adjacent ports is improved. By putting four output ports on the same side, the practicability of the circuit is improved. The test results show that the input return loss is >17.5 dB and insertion loss is <2 dB in 9–10.5 GHz.
Reliability verification‐based convolutional neural networks for object tracking
Authors: Hu Xiaopeng , Li Jingting , Yang Yan , Wang Fan
Published: October 2018

The authors propose a tracking algorithm based on the reliability analysis of the convolutional neural network to avoid drift. In general, most tracking algorithms implemented with the deep network consist of a single network; they obtain the tracking results according to the confidence and perform updates with the samples, which are collected based on the previous target state. However, this kind of algorithm relies heavily on the accuracy of tracking results, and slight deviations can lead to improperly labelled training samples and degrade the network. Therefore, they design a verification network to guarantee the reliability of the tracking network by correcting the results and it can be connected to a tracking network by sharing convolutional layers. The reliability verification network estimates the accuracy of the results of the tracking network and discards ambiguous results to avoid accumulating errors. Specifically, the verification network can distinguish the target from the confused candidates more precisely because of the optimised training data. The training samples of the verification network consist of characteristics and labels, and they are optimised by feature selection and label enhancement, respectively. The experimental results illustrate the outstanding performance compared with several state‐of‐the‐art methods on the challenging video sequences.
Review of trajectory optimisation for connected automated vehicles
Authors: Wang Yu , Li Xiaopeng , Yao Handong
Published: October 2018

The connected automated vehicle (AV) technologies provide unprecedented opportunities for precisely controlling and optimising vehicle trajectories to improve traffic performance from the aspects of travel time reduction, driving comfort improvement, fuel consumption and emission savings and safety enhancement. Recently, connected and automated vehicle (CAV) trajectory optimisation research has become a hot topic. This study provides an overview of studies on CAV trajectory optimisation in the road traffic context, with a focus on the literature in the past decade. Rather than exhausting all related studies, this review focuses on categorising representative studies with several relevant criteria. On the basis of the review outcomes, research gaps and needs are discussed to facilitate future research.
Microstructure and enhanced dielectric properties of BaTiO3 –SiO2 nanocomposites using hydrogen treated nanoparticles
Authors: Tong Yang , Talebinezhad Hossein , Lu Xu , Cheng Zhongyang , Hill Curtis , Tucker Dennis
Published: October 2018

BaTiO3 (BT) nanoparticles treated in H2 and then coated with a layer of SiO2 were used as the starting material to synthesise BT–SiO2 nanocomposites through the conventional ceramic process. A denser morphology was obtained in the BT–SiO2 composites. The H2 treatment induced not only the oxygen vacancies, but also other changes (i.e. ionic disorders) in the BT. These ionic disorders were more permanent and enhanced the reaction between the BT and SiO2 during the sintering process. Comparing with the nanocomposites sintered from the untreated BT nanoparticles, the nanocomposites sintered from the H2 treated BT nanoparticles exhibit an enhanced dielectric performance (i.e. a higher dielectric constant and a high electric breakdown field). Among the temperatures (i.e. 850, 900, 950 and 1000°C) used to treat the BT nanoparticles in H2, it is experimentally found that 950°C is the best. For example, for the composites with 20 wt% SiO2, the dielectric constant is enhanced more than four times and the breakdown field is enhanced by about 30%. It is believed that the enhancement in the dielectric response is due to the dipoles formed by the ionic disorders, especially the acceptor defects.
A simplified model for the dynamic analysis and power generation of a floating offshore wind turbine
Authors: Lerch Markus , De-Prada-Gil Mikel , Molins Climent
Published: October 2018

This paper presents a simplified model for the dynamic analysis of a floating off-shore wind turbine (FOWT), which can be suitable for early feasibility and pre-engineering studies, where the complete system has to modeled in order to predict its behavior and to assess the performance. The model solves the equation of motion in time domain and considers Morison equation for computing the hydrodynamic loads. The aerodynamic loads are included by considering the wind thrust at hub height and the loads from the mooring system have been computed as a non-linear model. A methodology is also presented for calculating the structural properties of the system. The model is tested for two load cases and compared to results obtained with the more complex model FAST. The comparison between the response of the models is satisfactory. The simplified model allows to capture the main motions of the FOWT with an acceptable accuracy. A further feature of the model is to calculate the power generation of the floating wind turbine. The results show that the losses in comparison with a bottom-fixed off-shore wind turbine are below 1% or 1.1% according to the load case, which confirms the good performance of the studied FOWT.
Demonstration of a microgrid manager in a distribution grid with high PV penetration and Storage: La Graciosa case study
Authors: Domínguez-López Guillermo , Paradell-Solà Pol , Domínguez-García José Luis , Rodríguez-Rivero Jacob , Sánchez-Cifuentes Jorge
Published: October 2018

Future power systems with high penetration of distributed energy resources (DER) and information and communication technology (ICT) will allow increasing the controllability and observability of the grid. However, new challenges for low voltage distribution networks has arisen where the increasing DER is mainly photovoltaic (PV) installed on the roofs of buildings. This type of generation is variable and generates disturbances in the network. Islands are ideal to experience and install new technologies since are weak grids and the penetration of PV will lead to bidirectional power flows at distribution level, thus a smart control will be required. This article aims to present and innovative tool for the distribution system operators (DSOs) to monitor and manage grid operation. In near future, both DER and client’s flexibility will increase. New monitoring and control tools for DSOs are essential. Furthermore, the grid operation optimization is needed to accommodate the expected DER installations and the active participation of consumers’ flexibility services in markets ensuring system efficiency. This tool is tested on “La Graciosa” grid, one of the Canary Islands, to show its benefit. The grid studied includes a hybrid energy storage system (HESS), PV generators, controllable/uncontrollable loads and equipment to monitor power flows.
Evaluation of a hybrid system to improve the electrical efficiency in photovoltaic panels
Authors: Valencia Juan C , Diaz Mauricio , Giraldo Carlos
Published: October 2018

This project shows a photovoltaic hybrid system (PHS) that follows the sun using electronic and mechanic devices and reduces the solar panel’s temperature with water in order to increase the energy obtained. The system was designed and implemented with a 1-axis solar tracker system and a water cooling system. PHS allows solar radiation beams to fall almost perpendicularly and decreases the temperature of the solar panel. Finally, its performance is compared against a traditional fixed photovoltaic system (FPS) oriented at 15° facing south. Experiments were made during only seven days in a year between December 1st and December 19th of 2017 in Guadalajara de Buga, Valle del Cauca, Colombia. Tests consisted of using the same electric loads at 20%, 40% and so on until 100% of the total power capacity of the solar panels. Results points out that electrical efficiency of the PHS increased 5.03% compared to the FPS on the same environmental conditions. Finally, PHS shows daily additional average power between 37% and 40% when it is loaded with electric loads at 80% and 100%.
First results on the K+ → π+vv¯ decay search from NA62
Authors: Duk Viacheslav
Published: October 2018

The precise measurement of the branching ratio of an ultrarare decay K+ → π+vv¯ (~10-10 according to the calculation within the Standard Model) allows to probe New Physics via indirect effects at mass scales higher than those accessible at the LHC. The NA62 experiment at the CERN SPS is aimed at measuring this branching ratio with the 10% precision. To achieve such level of precision, a novel decay-in-flight technique is used. The statistics collected during the first NA62 physics run in 2016 allowed to demonstrate the proof of the experimental method and obtain O(10-10) single event sensitivity. The preliminary results based on the 2016 data set are described.
Recent results from the ALICE Experiment at LHC
Authors: Ristea Catalin
Published: October 2018

ALICE (A Large Ion Collider Experiment) at the LHC performed high statistics measurements in Pb-Pb collisions at the top LHC energy, complemented with large recent reference datasets in elementary proton-proton collisions at the same energy. Elementary pp collisions are serving as baseline for testing QCD properties and allow the study of the changes induced by the hot and dense medium produced in heavy ion collisions. Key observables like nuclear modification factors, jet production, flow phenomena and spectra for identified particles, related to the different stages of collision evolution, are presented and compared with the most recent results from p-Pb and Xe-Xe collisions, thus allowing to probe both initial cold nuclear matter and final state effects, combined with the system size dependence of the measurements.
Advanced stream search for galaxy clusters with multifrequency microwave data
Authors: Verkhodanov Oleg , Verkhodanova Natalia , Ulakhovich Olesya , Solovyov Dmitrij , Khabibullina Margarita
Published: October 2018

Based on the data from the Westerbork Northern Sky Survey performed at a frequency of 325 MHz in the range of right ascensions 0h ≤ α < 2h and declinations 29o < δ < 78o and using multifrequency Planck maps, we selected candidate objects with the Sunyaev-Zeldovich effect. The list of the most probable candidates includes 381 sources. It is shown that the search for such objects can be accelerated by using a priori data on the negative level of fluctuations in the CMB map with remote low multipoles in the direction to radio sources.
First results on precision constraints on Z - Z′ mixing with ATLAS and CMS diboson production data at the LHC at 13 TeV and predictions for Run II
Authors: Pankov Alexander , Bednyakov Vadim
Published: October 2018

The study of electroweak boson pair production provides a powerful tool to search for new phenomena beyond the Standard Model (SM). Extra neutral vector bosons Z′ decaying to charged gauge vector boson pairs W+W- are predicted in many scenarios of new physics, including models with an extended gauge sector. The diboson production allows to place stringent constraints on the Z-Z′ mixing parameter ξ and Z′ mass, MZ′. We present the Z′ exclusion region in the ξ - MZ′ plane for the first time by using data comprised of pp collisions at √s = 13 TeV and recorded by the ATLAS and CMS detectors at the CERN LHC, with integrated luminosities of 36.1 and 35.9 fb-1, respectively. The exclusion region has been significantly extended compared to that obtained from the previous analysis performed with Tevatron data, as well as with LHC data collected at 7 and 8 TeV. Also, we found that these constraints on the Z-Z′ mixing factor are more severe than those derived from the global analysis of electroweak data. Further improvement on the constraining of this mixing can be achieved from the analysis of data to be collected at higher luminosity expected in Run II.
Restrictions on the mass of the KK excitation W′ from the Higgs boson diphoton decay and the single top production.
Authors: Baskakov Alexey , Boos Eduard , Bunichev Viacheslav , Perfilov Maxim , Volobuev Igor
Published: October 2018

In the framework of stabilized brane-world models we consider the contribution of the W′ boson and the rest of the W boson KK tower to the Higgs boson decay to two photons and to the single top production process. Comparing the signal strengths calculated in this approach with the experimental ones obtained at the LHC and taking into account the expected improvements at future high luminosity HL-LHC, high energy HE-LHC, and FCC-hh projects, we get predictions for the limits on the W' boson mass depending on its coupling to SM fermions.
Contribution of charm to rare radiative leptonic B-decays
Authors: Kozachuk Anastasiia
Published: October 2018

We revisit rare radiative leptonic decays Bd,s → γμ+μ- and Bd,s → γe+e- in the Standard Model and obtain predictions for a number of differential distributions in these decays with special emphasis on the contribution of charm-quark loops.
The CMS Particle Flow Algorithm
Authors: Dordevic Milos
Published: October 2018

The event reconstruction at the Compact Muon Solenoid (CMS) experiment at the CERN Large Hadron Collider (LHC) is predominantly based on the Particle Flow algorithm. This algorithm for a global event description uses the information from all subdetector systems, unlike the previous, traditional approaches that were focused on the localized information in each subdetector. These traditional methods use the raw information (tracks, hits), while the Particle Flow algorithm completely reconstructs the event by identifying and reconstructing the comprehensive list of final-state particles (photons, electrons, muons, charged and neutral hadrons), resulting in superior reconstruction of jets, missing transverse energy, tau leptons, electrons and muons. This approach also allows for efficient identification and mitigation of the pileup effect. The concept and performance of the Particle Flow algorithm, together with the prospects for its development in the context of the upgraded CMS detector, are presented in this overview.
Resonances in positron scattering on a supercritical nucleus and spontaneous production of e+e- pairs
Authors: Godunov Sergey , Machet Bruno , Vysotsky Mikhail
Published: October 2018

Solving the Dirac equation for a positron in the Coulomb field of a nucleus with Z > Zcr we observe (confirm) the resonance dependence of the scattering phase δx on the energy εp of the positron. A physical interpretation of these resonances is suggested.
Breit-Wheeler pair production from Worldline Instantons
Authors: Satunin Petr
Published: October 2018

We calculate the cross-section of Breit-Wheeler process γγ → e+e- in external electric field below the perturbative threshold by the semiclassical method of worldline instantons.
Numerical estimate of minimal active-sterile neutrino mixing
Authors: Krasnov Igor
Published: October 2018

Seesaw mechanism constrains from below mixing between active and sterile neutrinos for fixed sterile neutrino masses. Signal events associated with sterile neutrino decays inside a detector at fixed target experiment are suppressed by the mixing angle to the power of four. Therefore sensitivity of experiments such as SHiP and DUNE should take into account minimal possible values of the mixing angles. We extend the previous study of this subject [1] to a more general case of non-zero CP-violating phases in the neutrino sector. Namely, we provide numerical estimate of minimal value of mixing angles between active neutrinos and two sterile neutrinos with the third sterile neutrino playing no noticeable role in the mixing. Thus we obtain a sensitivity needed to fully explore the seesaw type I mechanism for sterile neutrinos with masses below 2 GeV, and one undetectable sterile neutrino that is relevant for the fixedtarget experiments. Remarkably, we observe a strong dependence of this result on the lightest active neutrino mass and the neutrino mass hierarchy, not only on the values of CP-violating phases themselves. All these effects sum up to push the limit of experimental confirmation of sterile-active neutrino mixing by several orders of magnitude below the results of [1] from 10-10 - 10-11 down to 10-12 and even to 10-20 in parts of parameter space; non-zero CP-violating phases are responsible for that.
The proton size puzzle: experiment vs theory.
Authors: Dorokhov A. E. , Martynenko A. P. , Martynenko F. A. , Radzhabov A. E.
Published: October 2018

Current status of the proton size puzzle from experimental and theoretical points of view is briefly discussed. The interest to these studies is primarily related to experiments conducted by the CREMA collaboration (Charge Radius Experi- ments with Muonic Atoms) with muonic hydrogen and deuterium by methods of laser spectroscopy. As a result a more accurate value of the proton charge radius was found to be rp = 0:84184(67) fm, which is different from the value recommended by CODATA for 7σ. In the second part we discuss recent calculations of the contribution of light pseudoscalar (PS) and axial-vector (AV) mesons to the interaction operator of a muon and a proton in muonic hydrogen atom, with the coupling of mesons to the muon being via two-photon intermediate state. Numerical estimates of the contributions to the hyperfine structure of the spectrum of the S and P levels are presented. It is shown that such contribution to the hyperfine splitting in muonic hydrogen is rather important for a comparison with precise experimental data.
Exotics at Our Home
Authors: Achasov Nikolay
Published: October 2018

1. Light Scalars as Four-Quark States 2. Isotensor Tensor E(1500 - 1600) State 3. X(3872) State as Charmonium χc1(2P) 4. Two-gluon Annihilation of Charmonium χc2(2P)
The construction of RFT from the Lipatov’s effective action
Authors: Bondarenko Sergey , Pozdnyakov Semyon
Published: October 2018

We consider the formalism of small-x effective action for reggeized gluons, see [1-3]. We construct the perturbation theory based on the knowledge of the classical solutions of equations of motion (written with NNLO precision) and loops contributions to the effective action. Applications of the obtained results are also discussed.
Direct photon production in pp, p–Pb and Pb–Pb collisions measured with the ALICE experiment
Authors: Peresunko D.
Published: October 2018

We review recent ALICE results on direct photon production in pp, p–Pb and Pb–Pb collisions at LHC energies. In light systems, pp and p–Pb, no signal of direct photons at low pT < 3-5 GeV/c is observed within uncertainties, while at high pT our measurements are consistent with NLO pQCD calculations. In central and mid-central Pb–Pb collisions a thermal photon contribution is observed at low pT < 3 - 4 GeV/c with slopes Teff = (304 ± 11stat ± 40syst) MeV and (407 ± 61stat ± 96syst) MeV respectively. A collective elliptic flow of direct photons is measured and appeared to be close to the decay photon flow.
Open Charm measurements at the NA61 experiment at CERN SPS
Authors: Larsen Dag , Merzlaya Anastasia
Published: October 2018

The strong interactions programme of the NA61/SHINE experiment at CERN SPS has been extended through the use of new silicon Vertex Detector which provides precise measurements of exotic particles with short lifetime. The detector was designed to meet the challenges of primary and secondary vertexes reconstruction at high spatial resolution. An initial version of the Vertex Detector called SAVD (Small Acceptance Vertex Detector) was installed last end of 2016, and data was from Pb+Pb collisions was collected in 2016, for Xe+La in 2017, as well as further Pb+Pb collisions this year. First indication of a D0 peak at SPS energies has been observed. The physics motivation behind the open charm measurements will be discussed, as well as the analysis of collected data on open charm production and the future plans of open charm measurements in NA61/SHINE experiment related to the upgraded version of the vertex detector.
Anisotropic (v1 and v2) Flow in Relativistic Heavy-Ion Collisions at Energies between 4 GeV and 200 GeV
Authors: Bravina L.V. , Kvasiuk Yu. , Sivoklokov S.Yu. , Vitiuk O. , Zabrodin E.E.
Published: October 2018

Basic features of directed and elliptic flows of identified hadrons in heavy-ion collisions at intermediate and high energies are considered within two transport string models, UrQMD and QGSM. Both models indicate changing of the sign of proton directed flow at midrapidity from antiflow to normal flow with decreasing energy of collisions. The origin of this effect is traced to hadron rescattering in baryon-rich remnants of the colliding nuclei. To distinguish the effect of rescattering from the flow softening caused by creation of quark-gluon plasma one has to compare heavy-ion and light-ion collisions at the same energy. Both directed and elliptic flows at midrapidity are formed within t = 10-12 fm/c. The differences in the development of elliptic flows of mesons and baryons are found at high energies. These differences can be explained by dissimilar freeze-out conditions, thus suggesting simultaneous study of particle collective flow and freeze-out.
Holographic study of Wilson loop in the anisotropic background with confinement/deconfinement phase transition
Authors: Slepov Pavel
Published: October 2018

Within the bottom-up holographic QCD using anisotropic black brane solutions in 5D Einstein-dilaton-two-Maxwell system constructed in [1, 2], we study the temporal Wilson loops with arbitrary orientation in respect to the anisotropy direction. We calculate the minimal surfaces of the corresponding probing open string world-sheet in anisotropic backgrounds with various temperatures and chemical potentials. The dynamical wall locations, providing the quark confinement, depend on the orientation of the quark pairs, that gives a crossover transition line between confinement/deconfinement phases in the dual gauge theory.
Holographic anisotropic background with confinementdeconfinement phase transition
Authors: Rannu Kristina
Published: October 2018

We present new anisotropic black brane solutions in 5D Einsteindilaton- two-Maxwell system [1]. The anisotropic background is specified by an arbitrary dynamical exponent v, a nontrivial warp factor, a non-zero dilaton field, a non-zero time component of the first Maxwell field and a non-zero longitudinal magnetic component of the second Maxwell field. The blackening function supports the Van der Waals-like phase transition between small and large black holes for a suitable first Maxwell field charge. The isotropic case corresponding to v = 1 and zero magnetic field reproduces previously known solutions. We investigate the anisotropy influence on the thermodynamic properties of our background, in particular, on the small/large black holes phase transition diagram.
Exotic meson decays and polarization asymmetry in hadron environment with chiral imbalance
Authors: Putilova A.E. , Iakubovich A.V. , Andrianov A.A. , Andrianov V.A. , Espriu D.
Published: October 2018

The possibility of the formation of a local parity breaking in a quark-hadron medium is described as a result of a violation of chiral symmetry, i.e, the difference between the average numbers of right and left -handing quarks in the fireball after HIC.The phenomenology of LPB in the fireball induces the introduction of a topological charge and, accordingly, a topological (chiral) chemical potential. Using the effective meson Lagrangian motivated by QCD in the chiral medium the properties of light scalar and pseudoscalar mesons are analyzed. It is establish that exotic decays of scalar mesons arise as a result of mixing of π and a0 vacuum states in the presence of chiral imbalance. The pion electromagnetic formfactor obtains a parity-odd supplement which generates a photon polarization asymmetry in pion polarizability. We consider that the above-mentioned properties of LPB can be revealed in experiments on LHC, RHIC, CBM FAIR and NICA accelerators.
Affinity of NJL2 and NJL4 model results on duality and pion condensation in chiral asymmetric dense quark matter
Authors: Khunjua T. G. , Klimenko K.G. , Zhokhov–Larionov R. N.
Published: October 2018

In this paper we investigate the phase structure of a (1+1) and (3+1)-dimensional quark model with four-quark interaction and in the presence of baryon (μB), isospin (μI) and chiral isospin (μI5) chemical potentials. It is shown that the chemical potential μI5 promotes the appearance of the charged PC phase with nonzero baryon density. Results of both models are qualitatively the same, this fact enhances one's confidence in the obtained predictions. It is established that in the large-Nc limit (Nc is the number of colored quarks) there exists a duality correspondence between the chiral symmetry breaking phase and the charged pion condensation one.
Supersymmetry, quantum corrections, and the higher derivative regularization
Authors: Stepanyantz Konstantin
Published: October 2018

We investigate the structure of quantum corrections in N = 1 supersymmetric theories using the higher covariant derivative method for regularization. In particular, we discuss the non-renormalization theorem for the triple gauge-ghost vertices and its connection with the exact NSVZ β-function. Namely, using the finiteness of the triple gauge-ghost vertices we rewrite the NSVZ equation in a form of a relation between the β-function and the anomalous dimensions of the quantum gauge superfield, of the Faddeev-Popov ghosts, and of the matter superfields. We argue that it is this form that follows from the perturbative calculations, and give a simple prescription how to construct the NSVZ scheme in the non-Abelian case. These statements are confirmed by an explicit calculation of the three-loop contributions to the β-function containing Yukawa couplings. Moreover, we calculate the two-loop anomalous dimension of the ghost superfields and demonstrate that for doing this calculation it is very important that the quantum gauge superfield is renormalized non-linearly.
Bootstrapping the S5 partition function
Authors: Nieri Fabrizio , Pan Yiwen , Zabzine Maxim
Published: October 2018

We consider U(N) SQCD on S5 and propose a Higgs branch-like expression for its partition function. We support the result by arguing that the knowledge of certain BPS codimension 2 and 4 defects arising from Higgsing is enough to reconstruct the bulk partition function, and that the defect partition functions satisfy a set of non-perturbative Schwinger-Dyson equations. We show that the result is consistent with, and naturally come from, the BPS/CFT perspective. In this language, the defect partition functions are identified with free boson correlators of the q-Virasoro modular triple, and the constraint equations with Ward identities satisfied by the corresponding Dotsenko-Fateev q-conformal blocks, providing a natural basis to expand the S5 partition function.
Isometries of five-branes and T-duality
Authors: Musaev Edvard T.
Published: October 2018

T-duality chain starting from the NS5-brane is known to generate exotic backgrounds. These have been described as a DFT background whose orientation in the doubled space defines specific 10-dimensional solutions. The focus of this letter is at isometries of the corresponding background, their relation to the NS five-brane charge and the section constraint of DFT. This letter is based on the talk presented by the author at the conference QUARKS’18.
Ricci-flat metrics and Killing-Yano tensors
Authors: Bykov Dmitri
Published: October 2018

We consider the problem of constructing Ricci-flat metrics on the total space of the canonical bundle over the del Pezzo surface of rank one. We analyze the so-called ‘orthotoric metric’ and its first-order deformation, whose existence is compatible with the Calabi-Yau theorem.
On massive Nambu-Goldstone fields
Authors: Kharuk Ivan , Shkerin Andrey
Published: October 2018

We consider two theories undergoing the same spontaneous symmetry breaking pattern but with different representations of an order parameter under the Lorentz group. The effective description of the first theory includes a massive Nambu-Goldstone field, while in the second example it is absent. Based on this, we clarify the physical meaning of massive Nambu-Goldstone fields as non-radial modes needed to describe the fluctuations of an order parameter. The connection with the inverse Higgs phenomenon is also discussed.
Scattering formalism in the Casimir interaction of gratings and Chern-Simons layers
Authors: Marachevsky Valery N.
Published: October 2018

We describe scattering formalism to evaluate the Casimir energy of two gratings separated by a vacuum slit and the Casimir energy of two Chern- Simons layers in vacuum.
Metastable Q-balls
Authors: Nugaev Emin
Published: October 2018

We will breifly review application of Euclidean path integral technique for the study of quantum decay of the bound system in field theory with global U(1)-invariance. As an illustration of the method, we numerically compute the decay rate of metastable Q-ball to the leading semiclassical order and present interpolating formula for the whole region of metastability.
Fourth-derivative relativistic quantum gravity
Authors: Larin S.A.
Published: October 2018

We consider relativistic quantum gravity with the action including terms quadratic in the curvature tensor. This model is known to be renormalizable. We demonstrate that the model is also unitary. New expressions for the corresponding Lagrangian and the graviton propagator within dimensional regularization are derived. We argue that the considered model is the proper candidate for the fundamental quantum theory of gravitation.
Massive Gravitational Waves from Black Hole Inspirals in Quantum Gravity
Authors: Calmet Xavier , Latosh Boris
Published: October 2018

We show that alongside the already observed gravitational waves, quantum gravity predicts the existence of two additional massive classical fields and thus two new massive waves. We set a limit on their masses using data from Eöt-Wash-like experiments. We point out that the existence of these new states is a model independent prediction of quantum gravity. We explain how these new classical fields could impact astrophysical processes and in particular the binary inspirals of black holes. We calculate the emission rate of these new states in binary inspirals astrophysical processes.
No stable static spherically symmetric wormholes in Horndeski theory
Authors: Evseev Oleg , Melichev Oleg
Published: October 2018

We consider the most general theory of a single scalar field with the second order field equations, the Horndeski theory, in four-dimensional space-time. We show that static, spherically symmetric, asymptotically flat, Lorentzian wormholes are unstable in this theory.
Cosmological bounce in Horndeski theory and beyond
Authors: Kolevatov R. , Mironov S. , Rubakov V. , Sukhov N. , Volkova V.
Published: October 2018

We discuss the stability of the classical bouncing solutions in the general Horndeski theory and beyond Horndeski theory. We restate the no-go theorem, showing that in the general Horndeski theory there are no spatially flat non-singular cosmological solutions which are stable during entire evolution. We show the way to evade the no-go in beyond Horndeski theory and give two specific examples of bouncing solutions, whose asymptotic past and future or both are described by General Relativity (GR) with a conventional massless scalar field. Both solutions are free of any pathologies at all times.
Towards wormhole beyond Horndeski
Authors: Mironov S. , Rubakov V. , Volkova V.
Published: October 2018

We address the issue of whether a no-go theorem for static, spherically symmetric wormholes, proven in Horndeski theories, can be circumvented by going beyond Horndeski. We show that the ghost instabilities which are at the heart of the no-go theorem, can indeed be avoided. The wormhole solutions with the latter property are, however, strongly fine tuned, and hence it is likely that they are unstable. Furthermore, it remains unclear whether these solutions have other pathologies, like gradient instabilities along angular and radial directions.
Dark Matter and Baryon Asymmetry from the very Dawn of Universe
Authors: Ramazanov Sabir
Published: October 2018

We discuss a possibility of universally producing dark matter and baryon charge at inflation. For this purpose, we introduce a complex scalar field with the mass exceeding the Hubble rate during the last e-folds of inflation. We assume that the phase of the complex scalar is linearly coupled to the inflaton. This interaction explicitly breaking U(1)-symmetry leads to the production of a non-zero Noether charge. The latter serves as a source of dark matter abundance, or baryon asymmetry, if the complex scalar carries the baryon charge.
Ultra-high energy cosmic rays and the strongest AGN flares
Authors: Pshirkov Maxim , Nizamov Bulat
Published: October 2018

We perform an observational test of the hypothesis that ultra-high energy cosmic rays (E > 1020 eV) are accelerated in giant flares of active galactic nuclei (AGN). We use the observations of Fermi LAT during the first 7.4 years of the mission. We select highly variable AGNs with the redshift z ≤ 0:3 and use an empirical relation between the bolometric luminosity and the jet kinetic power in order to find the local kinetic emissivity of strong AGN flares: L ~ 1:1 × 1045erg Mpc-3 yr-1. This is approximately one order of magnitude larger than the UHECR emissivity estimated from the data of Pierre Auger and Telescope Array observatories which makes the whole scenarion feasible provided the acceleration spectrum is sufficiently hard and/or narrow.
Bound on a flux of ultra-high energy neutrinos in a scenario with extra dimensions
Authors: Astashenkov Mikhail , Kisselev Alexander
Published: October 2018

Assuming that a single-flavor diffuse neutrino flux dNv/dEv is equal to kE-2v in the energy range 1017 eV - 2:5 × 1019 eV, an upper bound on k is calculated in the ADD model as a function of the number of extra dimensions n and gravity scale MD. An expected number of neutrino induced events at the Surface Detector array of the Pierre Auger Observatory is estimated.
Photon splitting in strongly magnetized medium with taking into account positronium influence
Authors: Anikin R.A. , Chistyakov M.V. , Rumyantsev D.A. , Shlenev D.M.
Published: October 2018

The process of the photon splitting, γ → γγ, is investigated in strongly magnetized vacuum with taking into account positronium influence. The dispersion properties of photons and the new polarization selection rules are obtained. The absorption rate of the leading photon splitting channels are calculated with taking account of the photon dispersion and wave function renormalization.
FRP Strengthening of structures – bridging gaps in academic research and industry - 25-years’ experience creating innovation
Authors: Täljsten Björn
Published: October 2018

This paper presents experience how academic research and industrial needs can be bridged together, focusing on external bonding with FRP:s. The paper is based on personal experience from research at university level where the results was brought to the industry and then further developed. The work spans from theory that was incorporated in design manuals to practical instruction how to install FRP:s on site. The author discusses the research from the end of the 80ties until today and how this research successfully was implemented in the construction industry. At the end a process for innovation is presented, based on the finding from research and implementation. The overall work can be divided into five phases; research, development, demonstration, implementation and finally innovation.
Polymer-Concrete Composites for the repair of concrete structures
Authors: Czarnecki Lech
Published: October 2018

In less than one century concrete has become the most widely used construction material over the world. In less than half of century it is difficult to imagine a concrete totally without polymers. An implantation of polymers into concrete has taken effect in the form of Concrete Polymer Composite: C-PC. Since then (1975) the development of new concrete classes have been ongoing: C-PC = PMC + PCC + PI + PC, where PMC Polymer Modified Concrete (polymer cont. < 1% concrete mass); PCC Polymer Cement Concrete (> 1% concrete mass); PIC Polymer Impregnated Concrete (3-8% concrete mass), PC Polymer Concrete (8-12% concrete mass). Over the time the role of polymers have been extended and it is covered by polymer with additional preposition: polymers on concrete (overlays, coatings, waterproofing and bounding materials). All those polymer composites have been found irreplaceable application in concrete repairing industry. It is enough to say that in ten parts of the European Standards, EN 1504, the category “polymer” can be found 73 times, and that is a proof of the big significance of this material in the repairs and protection of concrete. Just for comparison reason, the term “cement” appears only 59 times in all parts of the EN 1504. Indeed, if repaired concrete is higher class then repairing material should content more polymer. The justification belongs to the adhesion, which is a fundamental challenge for concrete repair. But also short time to exploitation readiness and many others polymer composites advantages are taken into consideration. In the paper the question: how polymers enhance concrete repair performance? is discussed. The repair rules and methods versus polymer repair materials will be considered.