bluuebunny/crossref_metadata_2025 huggingface dataset:
N‐ϒ‐(l‐Glutamyl)‐l‐Selenomethionine Inhibits Fat Storage via the Stearoyl‐CoA Desaturases FAT‐6 and FAT‐7 and the Selenoprotein TRXR‐1 in Caenorhabditis elegans
Authors: Chang Chun‐Han , Liao Harrison Xian‐Qi , Hsu Fu‐Lan , Ho Chi‐Tang , Liao Vivian Hsiu‐Chuan
Published: November 2018

Scope

Selenium is an important nutrient for human health. The influence of dietary selenium on lipid metabolism remains largely unknown. N‐γ‐(l‐glutamyl)‐l‐selenomethionine (Glu‐SeMet) on inhibition of fat accumulation and its underlying mechanisms in the nematode Caenorhabditis elegans are investigated.

Methods and results

Triacylglyceride quantification and post‐fixed Nile red staining methods are conducted to evaluate fat accumulation in wild‐type N2 worms in normal or high‐glucose diet. Glu‐SeMet (0.01 µm) treatment effectively reduces fat storage in wild‐type N2 C. elegans in both a normal and high‐glucose diet. Further evidence shows that Glu‐SeMet (0.01 µm) decreases the ratio of oleic acid/stearic acid (C18:1Δ9/C18:0) using gas chromatography–mass spectrometry analysis. The mRNA levels of fatty acid stearoyl‐CoA desaturases, FAT‐6 and FAT‐7, and the mediator‐15 (MDT‐15) are downregulated while the wild‐type N2 worms are co‐treated with high glucose and Glu‐SeMet (0.01 µm). The effect of reduced fat accumulation is absent in fat‐6, fat‐7, and trxr‐1 mutant worms under high glucose and Glu‐SeMet (0.01 µm) co‐treatment.

Conclusions

This study demonstrates that Glu‐SeMet inhibiting fat accumulation may be associated with FAT‐6 and FAT‐7 and the selenoprotein TRXR‐1 in C. elegans. This study implies a potential for Glu‐SeMet as a new treatment for obesity or its complications.
Condition monitoring of cooling tower fan using K‐band Doppler radar
Authors: Im Yun‐Taek , Doo Seung‐Gyu , Hwang Jeong‐Sik
Published: November 2018

A contactless condition monitoring technique for cooling tower fans is proposed using K‐band Doppler radar. The system is realized using a commercial K‐band Doppler radar module, the Hilbert transform is adopted to minimize the hardware complexity, and the Fourier transform is used to analyze the received signal. The proposed system has several advantages. First, Doppler radar is less vulnerable to the adverse effects of scattering from mist or dust, since the wavelength of a microwave is longer than that of a laser. Second, the proposed radar system can be applied to any sized fans, although it is suitable for cooling tower fans. Third, it can be easily implemented in a low‐cost manner. The test results show that the RPM of the HANARO cooling tower fan agree with that of the motor in both low‐speed and high‐speed modes. The proposed system can be applied to the condition monitoring of cooling tower fans in thermal control systems.
Graphene‐based directive optical leaky wave antenna
Authors: Patel Shobhit K. , Sorathiya Vishal , Guo Tianjing , Argyropoulos Christos
Published: November 2018

We realized graphene‐based optical leaky wave antenna as an alternative to simple optical leaky wave antenna. The use of graphene in designing optical leaky wave antenna provides improved directivity. Tuning of this sharp directive pattern can be used for beam shaping of an optical antenna. The graphene layers are loaded in Si3N4 waveguide. The graphene layers are excited by a fixed voltage. Our results lead to graphene‐based design in the third window of optical communication. In addition, graphene‐based leaky wave design gives enhancement in different antenna parameters like reflection coefficient, transmission coefficient, and gain. The proposed graphene designs have directive response with high efficiency and are envisioned to become building blocks of several infrared systems which is going to be applicable in medical sensing systems.
Design of a compact low‐cost GPS antenna for high‐overload applications
Authors: Sun Siyang , Chen Xiaochen , Xiao Li , Liu Zheng , An Xudong , Wang Ruixin , Zhu Siting
Published: November 2018

A novel compact global positioning system antenna design of helical antenna operated at its normal mode is presented for high‐overload applications. A grounded matching stub is introduced for good impedance matching and a LNA module is implemented on ground board. The prototype of extremely compact size (22 × 19 mm2) is fabricated and experimentally investigated. The measured 10‐dB impedance bandwidth is almost 14 MHz around the center frequency 1575 MHz. An omnidirectional pattern in broadside of the antenna is achieved and the capability of stable signal reception under various motion attitude is verified by experiments. The proposed antenna is suitable for applications in systems where compact operation and high overload are the major concerns, especially for installation in an artillery fuze.
High gain dual band slot antenna loaded with frequency selective surface for WLAN/fixed wireless communication
Authors: Sah Shalini , Mittal Ashok , Tripathy Malay R
Published: November 2018

This study shows the gain enhancement achieved through dual band slot antenna incorporated with dual band frequency selective surface. In order to do this, at first, a dual band novel 7 × 7 spanner shape FSS is designed, and its operations is analyzed by using the ray tracing method. The second step involves designing the dual band slot antenna resonating at 3.53 and 6.2 GHz, respectively. The designed FSS is then used as superstrate on the slot antenna in which cavity resonance occurs due to multiple reflections and leaked out waves, thereby enhancing antenna's gain significantly on both the bands. Further, the overall gain of slot antenna with the superstrate is achieved as 13.00 and 13.92 dBi on the 2 respective resonant frequencies; this in turn results in a gain enhancement of 8.0 and 6.82 dB at 3.53 and 6.2 GHz, respectively. The measured results coincide verifying the results of the simulated structure. This is followed by a parametric analysis for air gap between FSS and the radiating antennas, which in turn have been designed for wireless and satellite communications.
Simultaneous effects of silanized coal fly ash and nano/micro glass fiber on fracture toughness and mechanical properties of carbon fiber‐reinforced vinyl ester resin composites
Authors: Nguyen Liem Thanh , Vu Cuong Manh , Phuc Bach Trong , Tung Nguyen Huy
Published: November 2018

In this study, the simultaneous effects of both silanized coal fly ash (S‐CFA) and nano/micro glass fiber (nGF) on fracture toughness and mechanical properties of vinyl ester (VE) resin filled with carbon fiber‐based composite materials were investigated. The CFA was treated with (3‐trimethoxysilyl) propyl methacrylate to introduce the methacryloxy groups into the surface of CFA, and was confirmed by using FTIR technique. The nGF and S‐CFA with different weight ratios were well mixed with VE resin by using of high‐speed mechanical stirrer, and ultrasonic technique before using as matrices for fabrication of carbon fiber‐based composite materials via sheet molding compound (SMC) method and hot curing processing. Many characteristics of both cured VE resin composites and carbon fiber‐based composite were examined such as mechanical properties, fracture toughness, and morphology. The results showed that by adding of both 0.1 wt% nGF and 1 wt% S‐CFA into VE resin the tensile strength, tensile modulus, flexural strength, KIC, impact strength as well as the Mode I interlaminar fracture toughness (GIC) of VE composites and carbon fiber based composites get optimum values and increased about 61.39%; 39.83%; 36.21%; 103.1%; 81.79%; 48.61%, respectively when compared with pristine materials. POLYM. ENG. SCI., 59:584–591, 2019. © 2018 Society of Plastics Engineers
Synergistic reinforcement of epoxy/basalt fiber composites with dimensionally different nanoparticles
Authors: Li Xi , Li Guoming , Su Xiaohong , Wang Zhenfei
Published: November 2018

Epoxy/basalt fiber composites were modified by 2D montmorillonite (MMT), 0D nanoSiO2, or 2D MMT/ 0D nanoSiO2 double nanoparticles. Mechanical tests showed that all the modified composites had considerably improved interlaminar shear strength and notch impact strength compared with the unmodified epoxy/basalt fiber composites, and that the double nanoparticle‐modified composites displayed the greatest improvement. X‐ray diffraction, transmission electron microscopy, and scanning electron microscopy revealed that co‐addition of 2D MMT and 0D nanoSiO2 into epoxy/basalt fiber composites produced a unique microstructure. The MMT was completely exfoliated into nanoscale mono‐sheets and interacted with nanoSiO2 particles to assemble into networks. The networks trapped many epoxy molecules within them and they tightly surrounded basalt fibers to form buffer layers. These results indicate that double nanoparticles of different dimensionality promote epoxy molecules to infiltrate between, combine with and coat basalt fibers more effectively than single nanoparticles, which facilitates better cooperation of epoxy and basalt fibers in resisting external forces. Modification with dimensionally different nanoparticles is an effective pathway to improve the performance of epoxy/basalt fiber composites and broaden their application fields. POLYM. ENG. SCI., 59:730–735, 2019. © 2018 Society of Plastics Engineers
Optimization strategy of the multihole products weld lines based on the multi‐objective evaluation system and kriging surrogate model
Authors: Wang Menghan , Tu Shunli , Yu Chunli
Published: November 2018

The plastic multihole products are widely used in Household Appliance and Automobile industry. The densely distributed weld lines resulting from the multiaperture structure seriously damage the surface appearance and mechanical properties of the products. However, there are relatively few studies on the optimization of weld lines of the plastic multihole products. Therefore, a multihole plate was taken as an example to exploit an optimization strategy for this kind of defects. The multi‐objective evaluation system was established to assess bonding quality of weld lines based on Numerical Simulation. And a multi‐objective optimization methodology was presented to efficiently optimize the process parameters. First, back propagation neural networks and Kriging method were combined to build the surrogate models based on the experiments arranged by Latin hypercube sampling. Second, a systematic test strategy was proposed to ensure high accuracy of the surrogate model. Then, the pareto optimal solution was obtained by integrating the surrogate model and Non‐dominated Sorting Genetic Algorithm II. Finally, the simulated and practical confirmation experiments indicate that bonding quality of weld lines can be effectively characterized and significantly improved by the multi‐objective evaluation system and the multi‐objective optimization methodology, respectively. POLYM. ENG. SCI., 59:781–790, 2019. © 2018 Society of Plastics Engineers
Long‐range molecular dynamics show that inactive forms of Protein Kinase A are more dynamic than active forms
Authors: Kalaivani R. , Narwani T. J. , de Brevern A. G. , Srinivasan N.
Published: November 2018

Many protein kinases are characterized by at least two structural forms corresponding to the highest level of activity (active) and low or no activity, (inactive). Further, protein dynamics is an important consideration in understanding the molecular and mechanistic basis of enzyme function. In this work, we use protein kinase A (PKA) as the model system and perform microsecond range molecular dynamics (MD) simulations on six variants which differ from one another in terms of active and inactive form, with or without bound ligands, C‐terminal tail and phosphorylation at the activation loop. We find that the root mean square fluctuations in the MD simulations are generally higher for the inactive forms than the active forms. This difference is statistically significant. The higher dynamics of inactive states has significant contributions from ATP binding loop, catalytic loop, and αG helix. Simulations with and without C‐terminal tail show this differential dynamics as well, with lower dynamics both in the active and inactive forms if C‐terminal tail is present. Similarly, the dynamics associated with the inactive form is higher irrespective of the phosphorylation status of Thr 197. A relatively stable stature of active kinases may be better suited for binding of substrates and detachment of the product. Also, phosphoryl group transfer from ATP to the phosphosite on the substrate requires precise transient coordination of chemical entities from three different molecules, which may be facilitated by the higher stability of the active state.
The “projectness” of MOC
Authors: Hoff Rainer
Published: November 2018

The safety community, bolstered by the PSM regulations, has emphasized the importance of proper management of change, “MOC,” to ensure safe, reliable and economic operation of chemical plants, refineries and increasingly, on‐ and off‐shore pipelines, and installations.

The majority of MOCs involve physical changes to facilities—a much smaller fraction of MOCs addresses procedure‐only changes, document‐only changes or organizational changes. Physical changes to facilities are implemented in different contexts such as maintenance work orders, project work orders, small capital projects, and large capital projects. Each of these contexts has its own notion of a “work process,” and the larger ones are very project‐centric.

Changes to facilities always involve BOTH an MOC and a “work process.” Some sites emphasize the work process aspects, driven by the existence of Enterprise Resources Planning systems, and handle the MOC essential elements poorly. Other sites burden the MOC process with many capital‐projects aspects and create a very complex change management environment. Surely there must be a happy medium?

This article analyzes data from case studies from actual implementation projects, identifies gaps and makes recommendations on the best practice for conjoining MOC and other work processes. © 2018 American Institute of Chemical Engineers Process Process Saf Prog 38:e12021, 2019
Nanoscale Physical and Chemical Structure of Iron Oxide Nanoparticles for Magnetic Particle Imaging
Authors: Hufschmid Ryan , Landers Joachim , Shasha Carolyn , Salamon Soma , Wende Heiko , Krishnan Kannan M.
Published: November 2018

In this work, the role of the nanoscale chemical and magnetic structure on relaxation dynamics of iron oxide nanoparticles in the context of magnetic particle imaging (MPI) is investigated with Mössbauer spectroscopy (MS) and electron energy loss spectroscopy (EELS). Two samples of 27 nm monodisperse iron oxide nanoparticles are compared, with and without an additional oxidation optimization step, with corresponding differences in structure and properties. Iron oxide nanoparticles synthesized in the presence of sufficient oxygen form single crystalline, inverse‐spinel magnetite (Fe3O4) and display magnetic properties suitable for MPI. A secondary wüstite (FeO) phase is observed in the diffraction pattern of unoptimized nanoparticles, which is antiferromagnetic and therefore unsuitable for MPI. Mössbauer spectra confirm the composition of the optimized nanoparticles to be ≈70% magnetite, with the remaining 30% oxidized to maghemite; in contrast, the as‐synthesized particles (without the oxidation step) contained about 40% wüstite and 60% magnetite. The authors use scanning transmission electron microscopy (STEM) with electron energy loss spectroscopy (EELS) to probe iron 2p‐3d electronic transitions and correlate their intensities with the oxidation state with sub‐nanometer spatial resolution. The optimally oxidized nanoparticles are uniform in crystallography and phase, while the mixed phase nanoparticles are core‐shell wüstite/magnetite. Further confirming the core‐shell structure of the mixed phase nanoparticles, considerable spin canting in the in‐field Mössbauer spectrum, likely caused by interface coupling, is observed.
Negative Stiffness Produced by Rotation of Non‐Spherical Particles and Its Effect on Frictional Sliding
Authors: Karachevtseva Iuliia , Pasternak Elena , Dyskin Arcady V.
Published: November 2018

Previous research shows that the rotation of non‐spherical particles under compression might lead to the effect of apparent negative stiffness. The effect of a rotating non‐spherical particle is modeled and it is shown that under displacement‐controlled loading its dynamics is equivalent to the dynamics of inverted pendulum. Analytically and experimentally, the eigenfrequency and the stability of the inverted pendulum under changing mass is investigated. It is demonstrated that the increase of total mass leads to the decrease of eigenfrequency of the system beyond that of an ordinary pendulum. Furthermore, there exists a value of the mass when the eigen frequency becomes zero. At this point the system loses its stability. This corresponds to the results obtained for a pair of coupled linear oscillators with one negative stiffness spring. Thus the concept of negative stiffness allows formulation of a simple and accurate model of inverted pendulum and rotating non‐spherical particles. It is shown that a set of randomly sized rotating non‐spherical particles create fluctuations in the friction force, which can form a mechanism of experimentally observed friction force fluctuations.
Thermal Stabilization of the Bulk‐Heterojunction Morphology in Polymer:Fullerene Solar Cells Using a Bisazide Cross‐Linker
Authors: Landerer Dominik , Sprau Christian , Baumann Daniel , Pingel Patrick , Leonhard Tobias , Zimmermann Diana , Chochos Christos L. , Krüger Hartmut , Janietz Silvia , Colsmann Alexander
Published: November 2018

After enhancing the power conversion efficiencies of organic solar cells beyond 10%, their long term stability has become the most urgent challenge in order to eventually integrate organic solar cells into end‐user products. Solar devices may have to endure harsh conditions already during their fabrication, typically requiring lamination temperatures up to 120 °C, critical for the initial performance of organic solar cells. In this work, polymer:fullerene bulk‐heterojunctions are fabricated with significantly enhanced thermal stability at 120 °C and beyond, by locking the bulk‐heterojunction morphology through incorporating the novel cross‐linkable bisazide 1,2‐bis((4‐(azidomethyl)phenethyl)thio)ethane (TBA‐X). Bulk‐heterojunctions comprising various light‐harvesting polymers and the industrially relevant fullerene acceptor PC61BM are investigated. Upon thermal annealing, the reference blends without the cross‐linking TBA‐X exhibit only moderate thermal stability and a relative loss of more than 70% of their initial performance, mainly originating from aggregation of the fullerene. In contrast, polymer:fullerene blends comprising TBA‐X retain up to 90% of their initial performance despite the harsh thermal annealing at 120 °C for up to 200 h.
Dimensional stability of deflection‐hardening hybrid fiber reinforced concretes with coarse aggregate: Suppressing restrained shrinkage cracking
Authors: Yıldırım Gürkan
Published: November 2018

High Performance Fiber Reinforced Concretes (HPFRCs) with deflection‐hardening capability are relatively novel materials with high damage tolerance. However, mixture proportions of such materials are mostly designed with fine aggregates for easier/homogenous fiber distribution and low matrix fracture toughness which increases the amount of cementitious materials as the main binder and related risk for dimensional instability, high cost, and environmental unfriendliness. Here, with the idea of developing concrete that is free of shrinkage‐related cracking at a more reasonable price, deflection‐hardening HPFRC mixtures incorporating different amounts of coarse aggregates (with maximum size of 12 mm) were developed with different mixture parameters (fiber types/dosages and fly ash contents) and tested for their dimensional stability by focusing mainly on the drying and restrained shrinkage measurements. Experimental results reveal that the combined effectiveness of utilizing hybrid fiber reinforcement and high amounts of coarse aggregates by properly adjusting the matrix properties without compromising high ductility (deflection‐hardening behavior) can help the realization of possible producibility of HPFRC mixtures that are completely free of restrained shrinkage‐related cracking. The findings of this study are believed to make a significant impact on the wide‐spread usage of deflection‐hardening HPFRC mixtures with similar ingredients to that of conventional concrete in actual field conditions.
Size effect in unnotched concrete specimens in bending: An analytical approach
Authors: Herbrand Martin , Stark Alexander , Hegger Josef
Published: November 2018

The size effect in unnotched concrete specimens in bending causes a higher modulus of rupture compared with its axial tensile strength. To determine the axial tensile strength of concrete from flexural tensile tests, size effect coefficients are, therefore, required. Analytical equations have been derived in the past by the application of nonlinear fracture mechanics and finite element parametric studies. However, the well‐known equations from the Model Codes do not represent the correct asymptotic behavior of the size effect which is problematic for high values of fracture energy, for example, for fiber‐reinforced concrete. Other equations known to the authors require knowledge of the characteristic length of the specimen, that is, their uniaxial tensile strength has to be known a priori. Therefore, this paper presents an analytical approach for the size effect in unnotched concrete specimens in bending that features correct asymptotic behavior and does not require a priori knowledge of the axial tensile strength. The comparison with finite element parametric studies and test results from the literature shows a very good agreement of the proposed equation from brittle to plastic behavior.
Gender‐Role Attitudes Among Immigrant Latinas: Empowering Women
Authors: Villalba Karina , Ramirez‐Ortiz Daisy , Dévieux Jessy G. , Attonito Jennifer , Rojas Patria
Published: November 2018

In general Latinos hold more conservative attitudes regarding gender roles when compared to Whites. However, Latinos born in the United States with higher education are more likely to have egalitarian gender role attitudes compared to Latino immigrants. The aim of this study was to analyze the relationship between gender role attitudes and acculturation, marianismo, and relationship control, among Latina immigrants living in the United States. A hierarchical regression and correlation analysis were used to measure the outcome of this study. A total of 234 women were included in the study with a mean age of 34 years old. The education level was less than high school (53 percent), with the majority employed (54 percent). The average time living in the United States was 8 years (SD = 2.0). Acculturation, marianismo, and relationship control were significantly associated with gender‐role, R2 = .207, F (3, 95) = 11.3, p = 0.001. The correlation analysis showed an inverse relationship between egalitarian attitudes and marianismo (r = −.304, p < .0005) and a positive relationship with acculturation (r = .295, p < .0005). Egalitarian gender role attitudes were observed with an inverse bidirectional relationship between marianismo and acculturation among Latino immigrant women living in the United States.
Delta shock waves for a system of Keyfitz‐Kranzer type
Authors: De la cruz Richard , Santos Marcelo
Published: November 2018

This paper is concerned with a hyperbolic system of conservation laws of Keyfitz‐Kranzer type. We show the existence of a delta shock wave solution using the vanishing viscosity method. The obtained solution satisfies the generalized Rankine‐Hugoniot relation and the entropy condition. As a consequence, we have also a uniqueness result for the obtained solution.
Flutter and vibration of elastically restrained nanowires under a nonconservative force
Authors: Xiao Q.‐X. , Li X.‐F.
Published: November 2018

This paper investigates vibration and flutter behavior of a cantilevered nanowire under the action of a subtangential follower force. Taking the surface effects into account, we apply Hamilton principle to derive a governing equation for an elastically restrained nanobeam. A characteristic equation is obtained. Force‐frequency interaction curves are displayed to show the influence of the surface elasticity, surface stress, restraint stiffness on divergence and flutter force. Natural frequencies and divergence loads are calculated for conservative forces at the free end. For a generalized follower force with various tangency coefficients, dynamic instability of nanocantilevers is presented and flutter loads are calculated for subtangential, supertangential and tangential follower forces. Flutter loads are sensitive to translational and rotational spring stiffness and surface elasticity. Some special cases with some vanishing parameters reduce to the well‐known results.
Nonrelativistic string theory and T-duality
Authors: Bergshoeff Eric , Gomis Jaume , Yan Ziqi
Published: November 2018

Abstract

Nonrelativistic string theory in flat spacetime is described by a two-dimensional quantum field theory with a nonrelativistic global symmetry acting on the worldsheet fields. Nonrelativistic string theory is unitary, ultraviolet complete and has a string spectrum and spacetime S-matrix enjoying nonrelativistic symmetry. The worldsheet theory of nonrelativistic string theory is coupled to a curved spacetime background and to a Kalb-Ramond two-form and dilaton field. The appropriate spacetime geometry for nonrelativistic string theory is dubbed string Newton-Cartan geometry, which is distinct from Riemannian geometry. This defines the sigma model of nonrelativistic string theory describing strings propagating and interacting in curved background fields. We also implement T-duality transformations in the path integral of this sigma model and uncover the spacetime interpretation of T-duality. We show that T-duality along the longitudinal direction of the string Newton-Cartan geometry describes relativistic string theory on a Lorentzian geometry with a compact lightlike isometry, which is otherwise only defined by a subtle infinite boost limit. This relation provides a first principles definition of string theory in the discrete light cone quantization (DLCQ) in an arbitrary background, a quantization that appears in nonperturbative approaches to quantum field theory and string/M-theory, such as in Matrix theory. T-duality along a transverse direction of the string Newton-Cartan geometry equates nonrelativistic string theory in two distinct, T-dual backgrounds.
Equations for general shells
Authors: Senovilla José M. M.
Published: November 2018

Abstract

The complete set of (field) equations for shells of arbitrary, even changing, causal character are derived in arbitrary dimension. New equations that seem to have never been considered in the literature emerge, even in the traditional cases of everywhere non-null, or everywhere null, shells. In the latter case there arise field equations for some degrees of freedom encoded exclusively in the distributional part of the Weyl tensor. For non-null shells the standard Israel equations are recovered but not only, the additional relations containing also relevant information. The results are applicable to a widespread literature on domain walls, branes and braneworlds, gravitational layers, impulsive gravitational waves, and the like. Moreover, they are of a geometric nature, and thus they can be used in any theory based on a Lorentzian manifold.
On dual description of the deformed O(N) sigma model
Authors: Litvinov A. V. , Spodyneiko L. A.
Published: November 2018

Abstract

We study dual strong coupling description of integrability-preserving deformation of the O(N) sigma model. Dual theory is described by a coupled theory of Dirac fermions with four-fermion interaction and bosonic fields with exponential interactions. We claim that both theories share the same integrable structure and coincide as quantum field theories. We construct a solution of Ricci flow equation which behaves in the UV as a free theory perturbed by graviton operators and show that it coincides with the metric of the η-deformed O(N) sigma-model after T -duality transformation.
Three-dimensional conformal geometry and prepotentials for four-dimensional fermionic higher-spin fields
Authors: Henneaux Marc , Lekeu Victor , Leonard Amaury , Matulich Javier , Prohazka Stefan
Published: November 2018

Abstract

We introduce prepotentials for fermionic higher-spin gauge fields in four space-time dimensions, generalizing earlier work on bosonic fields. To that end, we first develop tools for handling conformal fermionic higher-spin gauge fields in three dimensions. This is necessary because the prepotentials turn out to be three-dimensional fields that enjoy both “higher-spin diffeomorphism” and “higher-spin Weyl” gauge symmetries. We discuss a number of the key properties of the relevant Cotton tensors. The reformulation of the equations of motion as “twisted self-duality conditions” is then exhibited. We show next how the Hamiltonian constraints can be explicitly solved in terms of appropriate prepotentials and show that the action takes then the same remarkable form for all spins.
Conceptual Blending as an Interpretive Lens for Student Engagement with Technology: Exploring Celestial Motion on an Interactive Whiteboard
Authors: Gregorcic Bor , Haglund Jesper
Published: November 2018

We present and analyze video data of upper secondary school students’ engagement with a computer-supported collaborative learning environment that enables them to explore astronomical phenomena (Keplerian motion). The students’ activities have an immersive and exploratory character, as students engage in open-ended inquiry and interact physically with the virtual environment displayed on an interactive whiteboard. The interplay of students’ playful exploration through physical engagement with the simulation environment, their attention to physics concepts and laws, and knowledge about the real planets orbiting the Sun presents an analytical challenge for the researcher and instructor encountering such complex learning environments. We argue that the framework of conceptual blending is particularly apt for dealing with the learning environment at hand, because it allows us to take into account the many diverse mental inputs that seem to shape the student activities described in the paper. We show how conceptual blending can be brought together with theoretical ideas concerned with embodied cognition and epistemology of physics, in order to provide researchers and instructors with a powerful lens for looking critically at immersive technology-supported learning environments.
Intellectual humility and the epistemology of disagreement
Authors: Pritchard Duncan
Published: November 2018

It is widely accepted that one strong motivation for adopting a conciliatory stance with regard to the epistemology of peer disagreement is that the non-conciliatory alternatives are incompatible with the demands of intellectual character, and incompatible with the virtue of intellectual humility in particular. It is argued that this is a mistake, at least once we properly understand what intellectual humility involves. Given some of the inherent problems facing conciliatory proposals, it is maintained that non-conciliatory approaches to epistemic peer disagreement are thus on much stronger dialectical ground than many suppose, including some defenders of this line. In particular, non-conciliatory proposals can resist the idea that epistemic peer disagreement directly weakens one’s epistemic justification, as conciliatory views maintain. This means that the epistemic justification that our beliefs in this regard enjoy, and thus our knowledge, is more secure than conciliatory approaches to epistemic peer disagreement would suggest.
A CONDITIONAL EQUITY RISK MODEL FOR REGULATORY ASSESSMENT
Authors: Floryszczak A. , Lévy Véhel J. , Majri M.
Published: November 2018

We define and study in this work a simple model designed for managing long-term market risk of financial institutions with long-term commitments. It allows the assessment of solvency capital requirements and the allocation of risk budgets. This model allows one to avoid over-assessment of solvency capital requirements specifically after market disruptions. It relies on a dampener component in charge of refining risk assessment after market failures. Rather than aiming at a realistic and thus complex description of equity prices movements, this model concentrates on minimal features enabling accurate computation of capital requirements. It is defined both in a discrete and continuous fashion. In the latter case, we prove the existence, uniqueness and stability of the solution of the stochastic functional differential equation that specifies the model. One difficulty is that the proposed underlying stochastic process has neither stationary nor independent increments. We are however able to perform statistical analyses in view of its validation. Numerical experiments show that our model outperforms more elaborate ones of common use as far as medium-term (between 6 months and 5 years) risk assessment is concerned.
Post-transitional periodic flow in a straight square duct
Authors: Gavrilakis S.
Published: November 2018

Direct numerical simulation of incompressible turbulence in a straight square duct finds the post-transition flow evolving substantially, and for Reynolds numbers based on the friction velocity and duct hydraulic radius greater than 600 a two-structure secondary flow regime has been established, suggesting the coexistence of two distinct sources of mean streamwise vorticity. The nominal source terms in the equation for the mean streamwise vorticity involve turbulent variables only, that allow us to identify the dominant dynamical process that marks and/or sustains the transverse mean flow. Close to the corner a mean profile instability is dominant, while farther away turbulent streamwise vorticity intensification is broadly distributed near the duct walls. The instability-driven secondary velocity maximum on the duct diagonals scales with the friction velocity. There is limited scaling of turbulent intensities on the wall bisectors.
Three-dimensional direct numerical simulation of infrasound propagation in the Earth’s atmosphere
Authors: Sabatini R. , Marsden O. , Bailly C. , Gainville O.
Published: November 2018

A direct numerical simulation of the three-dimensional unsteady compressible Navier–Stokes equations is performed to investigate the infrasonic field generated in a realistic atmosphere by an explosive source placed at ground level. To this end, a high-order finite-difference method originally developed for aeroacoustic applications is employed. The maximum overpressure and the main frequency of the signal recorded at 4 km distance from the source location are about 4000 Pa and 0.2 Hz, respectively. The atmosphere is parametrized as a vertically stratified medium, constructed by specifying vertical profiles of the temperature and the horizontal wind which reproduce measurements. The computation is carried out up to 140 km altitude and 450 km range. The goal of the present paper is twofold. On the one hand, the feasibility of using a direct numerical simulation of the three-dimensional fluid dynamic equations for the detailed description of long-range propagation in the atmosphere is proven. On the other hand, a physical analysis of the infrasonic field is realized. In particular, great attention is directed towards some important phenomena which are not taken into account or not well predicted by classical propagation models. To begin with, the present study clearly demonstrates that the weakly nonlinear ray theory may lead to an incorrect evaluation of the waveform distortion of high-amplitude waves propagating towards the lower thermosphere. In addition, signals recorded in the shadow zones are investigated. In this regard, the influence on the acoustic field of temperature and wind inhomogeneities of length scale comparable with the acoustic wavelength is analysed. The role of diffraction at the thermospheric caustic is finally examined and it is pointed out that the amplitude of the source may have a strong impact on the length of the shadow zone.
Modeling migrant smuggling: Testing descriptive types against recent findings
Authors: Bilger Veronika
Published: November 2018

This article develops a typology of migrant smuggling. Six generic types of migrant smuggling that were originally produced in the early 2000s are reviewed against more recent empirical findings. These six types were developed in the context of the profound transformation faced by Europe over the course of the 1990s in terms of its geopolitical landscape, when the fall of the Iron Curtain and the dissolution of the Soviet Union and Yugoslavia resulted in an unprecedented magnitude of asylum migration, irregular migration flows, and migrant smuggling. Today, in the aftermath of the Arab spring protests and the outbreak of civil war in Syria, the phenomenon of migrant smuggling toward Europe has regained notoriety and relevance. The article concludes that the fundamental mechanisms and types of migrant smuggling that were identified more than a decade ago have persisted over time, but that certain changes in the modus operandi of migrant smugglers can be observed, changes that are linked to geopolitical, market, infrastructural, and other factors.
When elites polarize over polarization: Framing the polarization debate in Turkey – RETRACTED
Authors: Aydın-Düzgit Senem , Balta Evren
Published: November 2018

This article aims to explore the views of the Turkish elite on the state of polarization in Turkey. By identifying four political frames—namely, harmony, continuity/decline, conspiracy, and conflict—that selected Turkish political and civil society elites use in discussing the phenomenon of polarization in the country through their contributions to a workshop and in-depth qualitative interviews, the article finds that there is a considerable degree of polarization among the Turkish elite regarding their views on the presence of polarization in Turkey. Moreover, this overlaps with the divide between the government and the opposition in the country. An analysis of the justificatory arguments employed in constituting the aforementioned frames shows that, while those elites who deny the existence of polarization seek its absence in essentialist characteristics of society, in reductionist comparisons with history, or in internal/external enemies, those who acknowledge polarization’s presence look for its roots in political and institutional factors and processes. The article highlights how, given the denial of polarization by the pro-government elite and the substantial gap between the two camps’ justificatory narratives, the currently reported high rates of polarization in Turkey can, at best, be expected to remain as is in the near future, barring a radical change in political constellations.
Crossing the mountain and negotiating the border: Human smuggling in eastern Turkey
Authors: Biner Özge
Published: November 2018

Human smuggling is a complex process. Made up of actions both organized and chaotic, it compels migrants to deal with different structures and agents of power, among them smugglers, the state(s), and migrants’ own social networks. The current literature on human smuggling provides a detailed analysis of the different phases of this process, within which discussion of the structure and operation of this “business” can be situated. However, only minimal attention has been paid to migrants’ agency in the smuggling process. Engaging with recent perspectives in migration studies, which emphasize the need to conceptualize human smuggling by focusing on the interdependencies between the different actors involved, the analysis developed in this article aims to explore the different phases of the human smuggling process by focusing on the multilayered relations between smugglers and undocumented people. Drawing upon qualitative ethnographic fieldwork conducted with migrants on the Turkish-Iranian border, the article examines how the physical and sociopolitical conditions of border crossing affect people’s ways of thinking, behavior, and engagement with different structures of power. In doing so, the article attempts to further our understanding of how smuggled migrants mobilize their agency in such a way as to manipulate and challenge the system, as well as of how this process transforms migrants’ capacity to simultaneously recognize and unsettle state bordering practices.
Photometric and spectroscopic variability of the Be star 48 Lib: The relation between photometric variations and rotation
Authors: Ozuyar D. , Caliskan S. , Stevens I. R. , Elmasli A.
Published: November 2018

The purpose of this paper is to determine the origin of the photometric variations of 48 Lib using the data from theSTEREOand to investigate their relations with the disk structure. The photometric data comprise a period of five years from 2007 to 2011. The spectroscopic data covering the same time interval are provided from theBeSSdatabase. The Hαlines are examined by measuring their equivalent widths and line intensities. Hαvariations are then compared with those displayed by the photometric data. From the photometry, high-precision results (10−5c d−1in frequency and 10−4mag in amplitude) are obtained. It is detected that the star has shown 24 frequencies, mainly clustered around the peaks at 2.48896(1) and 5.08150(2) c d−1. The analysis reveals that the photometric frequencies are not due to pulsation, but caused by the rotation, and that the remaining frequencies arise from transient activities on or just above the photosphere. Also, it is shown that the spectroscopic data exhibit a significant Hαvariability, and that the Hαline variation depends on the variation of frequency and amplitude, something which has been often proposed in the literature but has never before been demonstrated observationally. This proves that the disk structure and photometric variations are related.
Mediators of increased self-harm and suicidal ideation in sexual minority youth: a longitudinal study
Authors: Oginni O. A. , Robinson E. J. , Jones A. , Rahman Q. , Rimes K. A.
Published: November 2018

Background

Sexual minority youth have elevated suicidal ideation and self-harm compared with heterosexual young people; however, evidence for mediating mechanisms is predominantly cross-sectional. Using a longitudinal design, we investigated self-esteem and depressive symptoms as mediators of increased rates of suicidal ideation or self-harm (SISH) among sexual minority youth, and the roles of childhood gender nonconformity (CGN) and sex as moderators of these relationships.

Method

In total, 4274 youth from the Avon Longitudinal Study of Parents and Children (ALSPAC) cohort reported sexual orientation at age 15 years, and past-year SISH at age 20 years. Self-esteem and depressive symptoms were assessed at ages 17 and 18 years, respectively. CGN was measured at 30–57 months. Covariates included sociodemographic variables and earlier measures of mediator and outcome variables. Mediation pathways were assessed using structural equation modelling.

Results

Sexual minority youth (almost 12% of the sample) were three times more likely than heterosexual youth to report past-year SISH (95% confidence interval 2.43–3.64) at 20 years. Two mediation pathways were identified: a single mediator pathway involving self-esteem and a multiple-mediated pathway involving self-esteem and depressive symptoms. Although CGN was associated with past-year SISH, it did not moderate any mediation pathways and there was no evidence for moderation by sex.

Conclusions

Lower self-esteem and increased depressive symptoms partly explain the increased risk for later suicidal ideation and self-harm in sexual minority youth. Preventive strategies could include self-esteem-enhancing or protecting interventions, especially in female sexual minority youth, and treatment of depression.
India’s nuclear force doctrine: Through the lens of jus ad bellum
Authors: Jain Isha , Seth Bhavesh
Published: November 2018

Nearly three decades after the Cold War, the present-day hostilities between India and Pakistan have shifted the focus of the threat of nuclear escalation to South Asia. It is in this context that this article seeks to assess the legality of India’s military nuclear doctrine under international law.

Academic literature on the use of nuclear weapons has largely shied away from discussing the legality of specific military doctrines or ‘policies of deterrence’ of the nuclear weapon states, treating them as issues of military strategy that are beyond the realm of international law. This article hopes to challenge that dichotomy.

Though several branches of international law are relevant to any discussion on nuclear weapons, this article shall only examine India’s nuclear doctrine through the lens of jus ad bellum. Specifically, this article shall focus on whether India’s nuclear doctrine constitutes a threat to use force, and if so, whether such threat is lawful. The article concludes that India’s nuclear doctrine can be construed to be a specific threat to use force against Pakistan, and that such threat may be unlawful for contemplating the disproportionate use of force.
The international law commission’s recent work on exceptions to immunity: Charting the course for a brave new world in international law?
Authors: Tladi Dire
Published: November 2018

In the summer of 2017, the International Law Commission adopted a draft article on exceptions to immunity. The Draft Article adopted provides that immunityratione materiaedoes not apply with respect to certain international crimes, namely crimes against humanity, the crime of genocide, war crimes, the crime of apartheid, torture, and enforced disappearances. These exceptions do not apply to immunityratione personae. The Draft Article was adopted after a vote and was severely criticized by some members of the Commission. It has also received mixed reaction from states, with some supporting its content while others have opposed it. In the aftermath of the adoption of the Draft Article, there has also been academic commentary, some of which has been critical. The (main) criticism levelled against the Draft Article is that it does not represent existing law and has no basis in the practice of states. This article seeks to evaluate the criticism by considering whether there is any state practice in support of the Draft Article proposed by the Commission.
Making a bicycle city: infrastructure and cycling in Copenhagen since 1880
Authors: EMANUEL MARTIN
Published: November 2018

Copenhagen is today praised as a truly bicycle-friendly city. The Danish capital earned its reputation as a ‘bicycle city’ early on. The network of bicycle infrastructure developed in the first half of the twentieth century was a result not least of a thriving cycling culture and the efforts made by cyclists’ organizations. In the following car-centric decades this network made cycling a more resilient practice than elsewhere, before cyclists and their lobby organizations managed, again, to pressure policy makers to renew supportive measures for cyclists. The article thus highlights two concepts: road users as potential co-producers of the mobility system as well as the obduracy of infrastructure and its capacity to preserve habits and cultures of the past.