bluuebunny/crossref_metadata_2025 huggingface dataset:
Under‐ice salinity transport in low‐salinity waterbodies
Authors: Olsthoorn Jason , Bluteau Cynthia E. , Lawrence Gregory A.
Published: August 2019

In cold and temperate climates, ice typically covers the surface of waterbodies during winter. Many of these systems are also weakly saline where, unlike seawater, the temperature of maximum density, , is higher than its freezing temperature, . This feature of the equation of state results in a stable temperature stratification when surface waters cool below . Conversely, salts excluded from the growing ice can destabilize the underlying water. Previous laboratory and field experiments demonstrated that excluded salts generate localized overturning and downward transport of salt, despite the persistence of a stable temperature gradient. Those experiments were not able to determine the processes responsible for this transport. Here, we use direct numerical simulations to visualize and characterize the plumes generated when ice excludes salt into a stable temperature gradient. We restrict our analysis to times much earlier than the diffusion timescale of temperature over the domain. We define a mass flux parameter ℜ that considers the strength of the reverse‐temperature stratification relative to the rate of salt exclusion. We identify two types of plumes whose characteristics depend mainly on
ℜ: double‐diffusive salt‐fingering plumes and convective plumes. The former encourages transport of salt to the bottom without significantly mixing the temperature stratification, while the latter tends to mix the water column. We apply a scaled mass flux parameter to published laboratory and field observations in low‐salinity systems. These limited observations compare favorably with our numerical analysis.
Water motion and vegetation control the pH dynamics in seagrass‐dominated bays
Authors: James Rebecca K. , van Katwijk Marieke M. , van Tussenbroek Brigitta I. , van der Heide Tjisse , Dijkstra Henk A. , van Westen René M. , Pietrzak Julie D. , Candy Adam S. , Klees Roland , Riva Riccardo E. M. , Slobbe Cornelis D. , Katsman Caroline A. , Herman Peter M. J. , Bouma Tjeerd J.
Published: August 2019

Global oceanic pH is lowering, which is causing great concern for the natural functioning of marine ecosystems. Current pH predictions are based on open ocean models; however, coastal zones are dynamic systems with seawater pH fluctuating temporally and spatially. To understand how coastal ecosystems will respond in the future, we first need to quantify the extent that local processes influence the pH of coastal zones. With this study, we show that over a single diurnal cycle, the total pH can fluctuate up to 0.2 units in a shallow seagrass‐dominated bay, driven by the photosynthesis and respiration of the vegetation. However, these biologically controlled pH fluctuations vary significantly over small distances. Monitoring conducted at neighboring sites with contrasting hydrodynamic regimes highlights how water motion controls the extent that the local pH is altered by the metabolism of vegetation. The interactive effects of hydrodynamics and vegetation were further investigated with an in situ experiment, where the hydrodynamics were constrained and thus the local water residence time was increased, displaying the counteractive effect of hydrodynamics on the pH change caused by vegetation. With this research, we provide detailed in situ evidence of the spatial variation of pH within marine ecosystems, highlighting the need to include hydrodynamic conditions when assessing the pH‐effects of vegetation, and identifying potential high‐pH refuges in a future low pH ocean.
Electromagnetic‐Dual Metasurfaces for Topological States along a 1D Interface
Authors: Bisharat Dia'aaldin J. , Sievenpiper Daniel F.
Published: August 2019

The discovery of topological insulators was rapidly followed by the advent of their photonic analogues, motivated by the prospect of backscattering‐immune light propagation. So far, however, implementations have mainly relied on engineering bulk modes in photonic crystals and waveguide arrays in two‐dimensional (2D) systems, which closely mimic their electronic counterparts. In addition, metamaterials‐based implementations subject to electromagnetic duality and bianisotropy conditions suffer from intricate designs and narrow operating bandwidths. Here, it is shown that symmetry‐protected topological states akin to the quantum spin‐Hall effect can be realized in a straightforward manner by coupling surface modes over metasurfaces of complementary electromagnetic responses. Specifically, stacking unit cells of such metasurfaces directly results in double Dirac cones of degenerate transverse‐electric (TE) and transverse‐magnetic (TM) modes, which break into a wide nontrivial bandgap at small interlayer separation. Consequently, the ultrathin structure supports robust gapless edge states, which are confined along a one‐dimensional (1D) line rather than a surface interface, as demonstrated at microwave frequencies by near‐field imaging. The simplicity and versatility of the proposed approach proves attractive as a tabletop platform for the study of classical topological phases, as well as for applications benefiting the compactness of metasurfaces and the potential of topological insulators.
Real‐Time In Situ Holographic Optogenetics Confocally Unraveled Sculpting Microscopy
Authors: Lerman Gilad M. , Little Justin P. , Gill Jonathan V. , Rinberg Dmitry , Shoham Shy
Published: August 2019

Two‐photon (2P) optogenetic stimulation is currently the only method for precise, fast, and non‐invasive cellular excitation deep inside brain tissue; it is typically combined with holographic wavefront‐shaping techniques to generate distributed light patterns and target them to multiple specific cells in the brain. During propagation in the brain, these light patterns undergo severe distortion, mainly due to scattering, which leads to a discrepancy between the desired and actual light distribution. However, despite its importance, measurement of these tissue‐induced distortions and their effects on the light patterns has yet to be demonstrated in situ. To this end, holographic optogenetics confocally unraveled sculpting (HOCUS), a system for real‐time in situ evaluation of holographic light patterns, based on confocally descanning the stimulation light's reflection from the brain, is developed. HOCUS measures both tissue and wave propagation properties and enables the real‐time measurement and correction of the dimensions and positions of holographic spots relative to neurons targeted for stimulation. It can also be used to measure tissue attenuation length, and thus should facilitate future attempts to optimize the generated hologram to pre‐compensate for tissue‐induced distortions, thereby improving the reliability of 2P holographic stimulation experiments.
Microstructural evolution and corrosion behavior of friction stir processed fine‐grained AZ80 Mg alloy
Authors: Huang Liying , Wang Kuaishe , Wang Wen , Peng Pai , Qiao Ke , Liu Qiang
Published: August 2019

Friction stir processing (FSP) and subsequent aging heat treatment were used to modify the microstructure of AZ80 magnesium alloy. The influence of FSP and aging heat treatment on the corrosion behavior was systematically studied by using potentiodynamic polarization, immersion, and slow strain rate tensile tests. The results revealed that FSP led to grain refinement, rapid dissolution of β‐phase, and the deflection of c‐axis from transverse direction (TD) and processing direction (PD) by approximately 55° and 25°, respectively, improving the static corrosion and stress corrosion cracking (SCC) resistance. The aging heat treatment rendered a little influence on the grain size and slightly affected the grain orientation. The content of β‐phase in FSP‐5 and FSP‐24 samples was 8.1 and 21.8 wt.%, respectively. Static corrosion and SCC resistance of FSP‐5 and FSP‐24 samples were lower than those of the FSP samples. Compared with FSP‐5 sample, the amount of β‐phase and the proportion of Al2O3 increased in FSP‐24 sample, leading to enhanced static corrosion and SCC resistance. SCC behavior was controlled by anodic dissolution, whereas the presence of hydrogen accelerated the SCC.
Polyethylene–Silica Nanocomposites with the Structure of Semi‐Interpenetrating Networks
Authors: Trofimchuk Elena S. , Meshkov Ivan B. , Kandlina Margarita N. , Nikonorova Nina I. , Muzafarov Aziz M. , Malyshkina Inna A. , Moskvina Marina A. , Grabovenko Fedor I. , Volynskii Aleksandr L.
Published: August 2019

Organic–inorganic nanocomposites with the structure of interpenetrating or semi‐interpenetrating networks are considered as advanced materials, since they have improved thermal and mechanical properties. An alternative approach to the preparation of such hybrid systems is proposed. It is based on the synthesis of silica from the precursor of hyperbranched polyethoxysiloxane by the hydrolytic condensation reaction in the volume of pores of a polymer matrix (bulk porosity is 40 vol%) stretched via the environmental crazing mechanism. Polyethylene–silica nanocomposites with the structure of semi‐interpenetrating networks when the content of silica is not less than 20–25 wt% are obtained. These composites can undergo an additional phase separation at a temperature of 160 °C (above the melting point of polyethylene), which is accompanied by an increase in the size of the polymer phase with the formation of macrophases. At the same time, the environment (orthophosphoric acid), in which the composite is heated, fills the pores that have appeared. As a result, the content of the third component with the new functionality increases up to 50 wt%, which allowed us to impart proton‐conducting properties to the composite material and preserve its shape stability.
Elaboration and Characterization of New Polymeric Membrane Based on Poly (N, N‐Diethyl Aminoethyl Methacrylate), Cellulose Triacetate, and Polysulfone
Authors: Abdellaoui Naima , Himeur Zahra , Arous Omar
Published: August 2019

Polymerinclusion membranes used for selective transport and separation of metallic ions have emerged in recent times. Their expansion depends on the method of preparation and the study of their structure. In this paper, an improvement of a novel category of thin films for performing ion separation was reported. The membranes were elaborated using a mixture of polymers: cellulose triacetate (CTA), polysulfone (PSu) and poly (N, N‐diethyl aminoethyl methacrylate) (PDEAEM), 2‐nitrophenyl pentyl‐ether (NPPE) was used as plasticizer, 15‐crown‐ether‐5 (15‐C‐5) was incorporated into the polymers as a metal ion carrier. The membranes (polymers − plasticizer − carrier) were synthesized using a new method and characterized by various techniques including Fourier Transform Infrared (FTIR) spectroscopy, Thermogravimetric Analysis (TGA) and Scanning Electron Microscopy (SEM). The CTA membranes exhibited well‐defined pores completely filled with the other polymers and plasticizer (NPPE). The surfaces of all synthesized membranes were found to be smooth. Overall, our results showed that the addition of plasticizer with polymers resulted in homogeneous and hydrophobic membranes. As application, quality parameters including electric conductivity, chlorides, bicarbonates and heavy metal (Pb2+) were determined before and after treatment of real wastewater using the synthesized polymeric membranes.
Efficient Transport of Heavy Metals Across Plasticized CTA/PVDF Membranes Mediated by Organo‐Phosphorous Carrier
Authors: Abdellaoui Naima , Arous Omar
Published: August 2019

This paper reports on the synthesis of a novel class of polymer inclusion membranes prepared by thermally‐induced phase separation using a mixture of two polymers: polyvinylidene fluoride (PVDF) and cellulose triacetate (CTA) plasticized by dioctylphtalate (DOP) and doped with organo–phosphoric compound: trioctylphosphine oxide noted (TOPO) as mobile carrier. The membranes (polymers − plasticizer − carrier) are characterized using physical techniques as well as Fourier transform infrared (FTIR) and thermo‐gravimetric analysis (TGA). All synthesized polymeric membranes are applied for investigation to the facilitated transport of Pb2+ and Cd2+ ions from aqueous nitrate source phase. All membranes are thermally stable up to nearly 178 °C. A study of the transport across a polymer inclusion membrane has shown that the lead transport efficiency is increased using TOPO as carrier. This study represents an interesting approach in the treatment of hydrometallurgical solutions using the TOPO neutral carrier mediated transport.
Traditional or behavioural? A combined decision making trial and evaluation laboratory and analytic network process approach for capital structure determinants of Turkish companies
Authors: Bank Semra , Arslantürk Çöllü Duygu , Bulut Halil Ibrahim
Published: August 2019

The aim of this study, following a new approach under the irrationality of managers, is to investigate the most effective determinants of capital structure decisions by combining traditional capital structure determinants with managerial‐behavioural biases. In line with this objective, considering the capital structure decision as one that employs multicriteria decision making, two of the multicriteria decision‐making methods—namely, Decision Making Trial and Evaluation Laboratory (DEMATEL) and Analytic Network Process (ANP)—are integrated into a hybrid method to analyse the interdependent relationships among traditional capital structure determinants and managerial‐behavioural biases and to prioritize them by making dual comparisons. Our findings show that managerial‐behavioural biases, not traditional capital structure determinants, are more effective in the capital structure decision and that anchoring is the most influential among managerial‐behavioural biases.
The marketing firm and co‐creation: The case of co‐creation by LEGO
Authors: Fagerstrøm Asle , Bendheim Liv Marie , Sigurdsson Valdimar , Foxall Gordon R. , Pawar Sanchit
Published: August 2019

This article discusses the marketer and customer co‐creation process within the context of bilateral contingencies. Bilateral contingencies occur when the marketers' behavior is reinforced (and/or punished) by the customers' behavior, whereas the behavior of the customers is reinforced (and/or punished) by the marketers' actions. Using the example of the LEGO community, we discuss how the marketers in the organization can respond to behaviors resulting from co‐creational customer–customer exchanges. This paper fills the knowledge gap by presenting a behavior analysis framework (theory of the marketing firm) for the empirical measurement of the co‐creation process.
A problem of determining a special spatial part of 3D memory kernel in an integro‐differential hyperbolic equation
Authors: Durdiev Umidjon , Totieva Zhanna
Published: August 2019

The inverse problem of determining 2D spatial part of integral member kernel in integro‐differential wave equation is considered. It is supposed that the unknown function is a trigonometric polynomial with respect to the spatial variable y with coefficients continuous with respect to the variable x. Herein, the direct problem is represented by the initial‐boundary value problem for the half‐space x>0 with the zero initial Cauchy data and Neumann boundary condition as Dirac delta function concentrated on the boundary of the domain
. Local existence and uniqueness theorem for the solution to the inverse problem is obtained.
A compact feeding network with radiation contribution for X‐band marine radar antenna array applications
Authors: Wang Zhongbao , Zhou Jianhao , Wang Ya‐Nan , Zhu Zihui , Fang Shaojun , Liu Hongmei
Published: August 2019

A compact feeding network with radiation contribution is proposed in designing microstrip patch array antenna (MPAA) for X‐band marine radar applications. The 1‐to‐4 feeding network consists of two circular‐sector patch balun, which can radiate electromagnetic wave with the same polarization of the patch array for enhancing the gain and suppressing the cross polarization. The feeding line in the series‐fed patch subarray is modified as the step‐impedance microstrip line to decrease the side‐lobe level (SLL). To verify the method, a 28‐element 9.41‐GHz MPAA with the proposed radiated feeding network is designed and fabricated. Measured results show that the impedance bandwidth is 183 MHz with a peak gain of 21.3 dBi. The SLL is 27.8 and 21.4 dB in the E‐ and H‐planes, respectively. The cross polarization is effectively reduced, which is lower than the copolarization of about 57 dB.
Quality of experience for unified communications: A survey
Authors: Baraković Husić Jasmina , Baraković Sabina , Cero Enida , Slamnik Nina , Oćuz Merima , Dedović Azer , Zupčić Osman
Published: August 2019

This paper presents a quality of experience (QoE) conceptual model to the context of unified communications (UC) through summary, classification, and discussion of multiple influence factors (IFs) and dimensions affecting it. A deep and comprehensive understanding of the IFs and their impact on QoE for a given service is an essential precondition for successful QoE management with the overall goal of prominently optimizing end‐user QoE, while making efficient use of network resources and maintaining a satisfied user base. The proposed conceptual model was used to conduct a qualitative meta‐analytical review of selected papers. The results of the qualitative review include various IFs, QoE dimensions, and key findings in the form of research recommendations for QoE in the context of UC.
A nonintrusive distributed reduced‐order modeling framework for nonlinear structural mechanics—Application to elastoviscoplastic computations
Authors: Casenave Fabien , Akkari Nissrine , Bordeu Felipe , Rey Christian , Ryckelynck David
Published: August 2019

In this work, we propose a framework that constructs reduced‐order models for nonlinear structural mechanics in a nonintrusive fashion and can handle large‐scale simulations. Three steps are carried out: (i) the production of high‐fidelity solutions by commercial software, (ii) the offline stage of the model reduction, and (iii) the online stage where the reduced‐order model is exploited. The nonintrusivity assumes that only the displacement field solution is known, and the proposed framework carries out operations on these simulation data during the offline phase. The compatibility with a new commercial code only needs the implementation of a routine converting the discretized solution into our in‐house data format. The nonintrusive capabilities of the framework are demonstrated on numerical experiments using commercial versions of Z‐set and Ansys Mechanical. The nonlinear constitutive equations are evaluated by using an external plugin. The large‐scale simulations are handled using domain decomposition and parallel computing with distributed memory. The features and performances of the framework are evaluated on two numerical applications involving elastoviscoplastic materials: the second one involves a model of high‐pressure blade, where the framework is used to extrapolate cyclic loadings in 6.5 hours, whereas the reference high‐fidelity computation would take 9.5 days.
Effects of flame‐retardant ramie fiber on enhancing performance of the rigid polyurethane foams
Authors: Cheng Jiaji , Wang Haodong , Wang Xu , Li Shaoxiang , Zhou Yue , Zhang Feng , Wang Yong , Qu Wenjuan , Wang Dong , Pang Xiujiang
Published: August 2019

Ramie fiber (RF) with excellent tensile strength was treated by a flame retardant and obtained the modified RF (MRF) that is incombustible. Then, MRF was used to improve the performance of rigid polyurethane foams (RPUF). The mechanical properties of the composite were investigated by compressive strength test and shear stress test. The fire characteristics were studied using a cone calorimeter. And the thermal decomposition and flammable properties were further evaluated using thermogravimetric analysis and limiting oxygen index. The results showed that MRF improve the mechanical properties of RPUF and eliminate the harm of flammability of RF on the RPUF.
Investigation of thermal comfort in nanofibrous three‐layer fabric for cold weather protective clothing
Authors: Ghaffari Shima , Yousefzadeh Maryam , Mousazadegan Fatemeh
Published: August 2019

The development of functional nanofiber materials with high specific surface area and porosity has been a highly interesting field of research in recent years due to its versatile properties for diverse applications. The combination of nanofibers into material clothes can open up new opportunities to improve comfort performance and thermal management properties. In this work, we demonstrated that the porous lightweight nanofibrous membrane could be coated on the fabric and laminated to improve its thermal comfort. The polyacrylonitrile was electrospun onto the surface of the polyester fabric with three different fineness and laminated with a warp knitted interlining in a controlled condition by sewing/fusing. The effect of the nanofibers diameter, sewing and fusing process on thermal insulation, air permeability, breathability, and water resistance of the obtained three‐layer samples were studied. The results showed that the presence of the nanofibers thin layer could improve the thermal comfort by controlling the studied parameters compared to the external face fabric as control. It was obtained that the fusing technique is more efficient than sewing for this purpose. The fused samples are waterproof and windproof, while instantly venting moisture and had good thermal insulation to protect the body from cold. POLYM. ENG. SCI., 59:2032–2040, 2019. © 2019 Society of Plastics Engineers
Comparative study of hydrophilic modification of polyacrylonitrile membranes by nitrogen and carbon dioxide RF plasma
Authors: Pal Dipankar , Neogi Sudarsan , De Sirshendu
Published: August 2019

Low temperature plasma treatment using radio frequency (RF) discharge of nitrogen and carbon dioxide gases was employed to enhance hydrophilicity of the polyacrylonitrile copolymer membrane surface. Influence of various plasma operating conditions, namely, power and exposure time on improvement of surface energy, permeability, and hydrophilicity of the membrane was investigated. Surface energy of RF nitrogen plasma‐treated membrane (70 W, 8 min) was enhanced by 70%. Surface etching due to plasma treatment was confirmed by weight loss of the treated membranes. About 78% increase in average pore size was obtained using RF carbon dioxide plasma treatment due to surface etching. Hydrophilicity of nitrogen plasma modified membrane was enhanced by 32% and it was maintained up to 100 days. The pore enlargement due to plasma etching is more effective compared to surface energy in enhancing permeability (70%) of RF carbon dioxide modified (70 W, 6 min) membrane throughout the aging period. The permeability of nitrogen RF plasma‐treated membrane is affected by surface energy and pore enlargement for initial 20 days of aging. After that, the permeability of treated PAN only depends on pore enlargement due to plasma etching. The nitrogen plasma modified surfaces appear to retain their functionality better than carbon dioxide plasma‐treated samples. Oxygen and nitrogen functional groups were identified to be responsible for surface hydrophilicity. POLYM. ENG. SCI., 59:2148–2158, 2019. © 2019 Society of Plastics Engineers
Barriers and facilitators to the implementation of a stepped care intervention for personality disorder in mental health services
Authors: Pigot Melissa , Miller Caitlin E. , Brockman Robert , Grenyer Brin F.S.
Published: August 2019

Background

Individuals with personality disorders—particularly borderline personality disorder—are high users of mental health treatment services. Emergency service responses often focus on crisis management, and there are limited opportunities to provide appropriate longer term evidence‐based treatment. Many individuals with personality disorders find themselves in a revolving cycle between emergency departments and waiting for community treatment. A stepped care approach may help to triage clients and allow access to interventions with minimal client, clinician and system burden. This study aims to understand the facilitators and barriers to real‐world implementation of a stepped care approach to treating personality disorders.

Methods

Managers and clinicians of health services engaged in implementation were interviewed to obtain accounts of experiences. Interviews were transcribed and thematically analysed to generate themes describing barriers and facilitators.

Results

Participants identified personal attitudes, knowledge and skills as important for successful implementation. Existing positive attitudes and beliefs about treating people with a personality disorder contributed to the emergence of clinical champions. Training facilitated positive attitudes by justifying the psychological approach. Management support was found to bi‐directionally effect implementation.

Conclusions

This study suggests specific organizational and individual factors may increase timely and efficient implementation of interventions for people with personality disorders. © 2019 John Wiley & Sons, Ltd.
Identification of the active site residues in ATP‐citrate lyase's carboxy‐terminal portion
Authors: Nguyen Vinh H. , Singh Noreen , Medina Ana , Usón Isabel , Fraser Marie E.
Published: August 2019

ATP‐citrate lyase (ACLY) catalyzes production of acetyl‐CoA and oxaloacetate from CoA and citrate using ATP. In humans, this cytoplasmic enzyme connects energy metabolism from carbohydrates to the production of lipids. In certain bacteria, ACLY is used to fix carbon in the reductive tricarboxylic acid cycle. The carboxy(C)‐terminal portion of ACLY shows sequence similarity to citrate synthase of the tricarboxylic acid cycle. To investigate the roles of residues of ACLY equivalent to active site residues of citrate synthase, these residues in ACLY from Chlorobium limicola were mutated, and the proteins were investigated using kinetics assays and biophysical techniques. To obtain the crystal structure of the C‐terminal portion of ACLY, full‐length C. limicola ACLY was cleaved, first non‐specifically with chymotrypsin and subsequently with Tobacco Etch Virus protease. Crystals of the C‐terminal portion diffracted to high resolution, providing structures that show the positions of active site residues and how ACLY tetramerizes.
Bridging the divide: Demographic dynamics and urban–rural polarities during economic expansion and recession in Greece
Authors: Salvati Luca
Published: August 2019

Demographic processes such as international migration, internal rural–urban movements, and short‐range residential mobility are increasingly driven by economic cycles. To assess how economic downturns have influenced demographic dynamics across regions in Greece—perhaps the European country most affected by the 2007 recession—the present study investigates spatial patterns of population increase and decline (2002–2017) in 51 prefectures, evaluating the contribution of natural balance (births minus deaths) and migration to total population growth during economic expansion (2002–2009) and recession (2010–2017). Population increased during economic expansion in semicentral regions with medium‐size urban centres, upper economic functions (university and international airport), and road infrastructures. Although natural balance was positive in almost all prefectures, migration contributed the most to population growth during 2002–2009. A generalised population decline was observed during recession, except in coastal areas specialised in tourism, the only regions still attracting migratory flows and maintaining a slightly positive natural balance. The largest urban areas (Athens, Salonika) experienced the highest rate of population decline, thanks to accelerated emigration and a moderately negative natural balance. Population dynamics during economic expansion contributed to increase a traditional density gap between urban and rural areas. Conversely, population dynamics during recession led to a spatial redistribution of population, reducing the gap between urban areas and rural, tourism‐specialised coastal districts. Evidence in our study supports a need for further investigation into the role of economic downturns in future population redistribution processes, specifically “shrinking” regions.
Real‐time differentiation of ethylbenzene and the xylenes using selected ion flow tube mass spectrometry
Authors: Allpress Caleb , Crittenden Deb , Ma Jing , McEwan Murray , Robinson Sage , Wilson Paul , Wu Melvin
Published: August 2019

Rationale

Monitoring of isomeric analytes using mass spectrometry usually requires a time‐consuming chromatographic separation of the analytes before analysis. Selected ion flow tube mass spectrometry (SIFT‐MS) can provide rapid direct analysis of ethylbenzene and xylene by utilizing the different reaction chemistry of the isomers. O2+ yields the same product ions from each isomer but in different ratios. OH− yields different product ions.

Methods

The reaction chemistry of C8H10 with the reagent ion OH− generated from a microwave discharge of moist air in a commercial SIFT‐MS instrument was utilized in this study. The product ion from OH− yielded ions at different masses for each isomer. To gain an understanding of how the product ion from ethylbenzene of HO2− was generated, a theoretical study of the potential reaction surface was undertaken that accounted for the experimental observations.

Results

Measurements of OH− with ethylbenzene showed the product ion to be HO2− at m/z 33. The reaction of OH− with xylene yielded the major product ion at m/z 105, C8H9−. HO2− also underwent a slow secondary reaction with CO2 and O2 present from air in the samples. These findings were supported by calculations of the potential energy surface for the reactions. Measurements made on a certified gas mixture of ethylbenzene and xylene in the concentration range up to 5000 ppbv gave a linear response for each analyte.

Conclusions

A fast, efficient method was developed for monitoring xylene and ethylbenzene in a mixture without the need for chromatographic separation before analysis using SIFT‐MS.
Mesenchymal stromal cell-derived extracellular vesicles for regenerative therapy and immune modulation: Progress and challenges toward clinical application
Authors: Allan David , Tieu Alvin , Lalu Manoj , Burger Dylan
Published: August 2019

Extracellular vesicles (EVs) derived from mesenchymal stromal cells (MSCs) have emerged as a promising form of regenerative therapy and immune modulation. Fundamental advances in our understanding of MSCs and EVs have allowed these fields to merge and create potential cell-free therapy options that are cell-based. EVs contain active cargo including proteins, microRNA, and mRNA species that can impact signaling responses in target cells to modify inflammatory and repair responses. Increasing numbers of preclinical studies in animals with various types of injury models have been published that demonstrate the potential impact of MSC-EV therapy. Although the emergence of registered clinical protocols suggests translation to clinical application has already begun, several barriers to more widespread clinical adoption remain. In this review, we highlight the progress made in MSC-derived small EV-based therapy by summarizing aspects pertaining to the starting material for MSC expansion, EV production, and isolation methods, studies from preclinical models that have established a foundation of knowledge to support translation into the patient setting, and potential barriers to overcome on the path to clinical application.

Significance statement Mesenchymal stromal cell-derived extracellular vesicles are a promising cell-free therapy for regenerative medicine and immune modulation with growing evidence from preclinical animal studies. Bioactive cargo in extracellular vesicles, including proteins, microRNA, and mRNA species, can impact signaling responses in target cells to modify inflammatory and repair responses. Although translation to clinical application has already begun, several barriers to more widespread clinical adoption remain.
Influence of surface characteristics on carbon disulfide catalytic hydrolysis over modified lake sediment biochar and research on deactivated mechanism
Authors: Song Xin , Sun Lina , Li Kai , Sun Xin , Wang Chi , Ning Ping
Published: August 2019

A series of lake sediment biochar (LSB) catalysts modified by metal oxides and basic functional groups were utilized for removal of carbon disulfide (CS2) in yellow phosphorus tail gas. The influences of preparation and modification conditions for surface characteristics of Fe‐KOH/LSB on removal of CS2 were investigated. Surface area and pore structure analyses indicated that preparation processes were aimed to increase the micropore structure of LSB. Diffuse reflection using transform of Fourier infrared radiation results showed that Fe had high hydrolysis activity for CS2 and low oxidation activity for H2S. Thermogravimetric/differential thermal analysis results indicated that low calcination temperature was not conducive to the generation of Fe2O3 and high calcination temperature led to the oxidation of LSB. CO2 temperature programmed desorption results stated that high alkalinity site strength could improve the catalytic hydrolysis performance. High KOH content could enhance alkalinity site strength but led to the block of pore. These modification factors mainly controlled the catalytic hydrolysis ability of Fe‐KOH/LSB. X‐ray photoelectron spectroscopy results claimed that the deactivation of Fe‐KOH/LSB was attributed to the generation of S and sulfate, and the consumption of active component. In the deactivation process, S and sulfate generated and covered the activity sites, and Fe2O3 was converted into FeSO4 or Fe2(SO4)3, which led to the deactivation.
Trading wind power through physically settled options and short‐term electricity markets
Authors: Papakonstantinou Athanasios , Champeri Georgia , Delikaraoglou Stefanos , Pinson Pierre
Published: August 2019

Wind power producers participating in today's electricity markets face significant variability in revenue streams, with potential high losses mostly due to wind's limited predictability and the intermittent nature of the generated electricity. In order to further expand wind power generation despite such challenges, it is important to maximize its market value and move decisively towards economically sustainable and financially viable asset management. In this paper, we introduce a decision‐making framework based on stochastic optimization that allows wind power producers to hedge their position in the market by trading physically settled options in futures markets in conjunction with their participation in the short‐term electricity markets. The proposed framework relies on a series of two‐stage stochastic optimization models that identify a combined trading strategy for wind power producers actively participating in both financial and day‐ahead electricity markets. The proposed models take into consideration penalties from potential deviations between day‐ahead market offers and real‐time operation and incorporates different preferences of risk aversion, enabling a trade‐off between the expected profit and its variability. Empirical analysis based on data from the Nordic region illustrates high efficiency of the stochastic model and reveals increased revenues for both risk neutral and risk averse wind producers opting for combined strategies.
Linearised actions for $$ \mathcal{N} $$ -extended (higher-spin) superconformal gravity
Authors: Buchbinde Evgeny I. , Hutchings Daniel , Hutomo Jessica , Kuzenko Sergei M.
Published: August 2019

Abstract

The off-shell actions for

$$ \mathcal{N} $$

N

-extended conformal supergravity theories in three dimensions were formulated in [1, 2] for 1 ≤

$$ \mathcal{N} $$

N

≤ 6 using a universal approach. Each action is generated by a closed super three-form which is constructed in terms of the constrained geometry of

$$ \mathcal{N} $$

N

-extended conformal superspace. In this paper we initiate a program to recast these actions (and to formulate their higher-spin counterparts) in terms of unconstrained gauge prepotentials as integrals over the full superspace. We derive transverse projection operators in

$$ \mathcal{N} $$

N

-extended Minkowski superspace and then use them to construct linearised rank-n super-Cotton tensors and off-shell

$$ \mathcal{N} $$

N

-extended superconformal actions. We also propose off-shell gauge-invariant actions to describe massive higher-spin super-multiplets in

$$ \mathcal{N} $$

N

-extended supersymmetry. Our analysis leads to general expressions for identically conserved higher-spin current multiplets in

$$ \mathcal{N} $$

N

-extended supersymmetry.
Ticket splitting, strategic voting and personal vote in the 2012 Mongolian elections
Authors: Maškarinec Pavel
Published: August 2019

This article examines ticket splitting under Mongolia's new mixed-member majoritarian system used for the elections in 2012, reaching several conclusions. First, we confirm that strategic ticket splitting depends on party size, as especially candidates of larger parties receive, on average, more district votes. Second, we show that strategic voting is not a universal phenomenon under the Mongolian mixed-member majoritarian system. Finally, as personal vote rather than strategic voting generally influences electoral behaviour of Mongolian voters at the district level, we hypothesize that institutional factors alone are not sufficient to explain both ticket splitting and strategic voting.
Monotheism and the Meaning of Life
Authors: Mawson T. J.
Published: August 2019

Monotheism and the Meaning of Life explores the role of God, and the relationship to the question 'What is the meaning of life?' for adherents of the main monotheistic religions - Judaism, Christianity and Islam. Exploring the various senses of 'meaning' and 'life', Mawson argues that there are various questions implicit in the notion of the meaning of life and that the God of monotheistic religion is central to the correct answers to all of them.
Thermal fluctuations in capillary thinning of thin liquid films
Authors: Shah Maulik S. , van Steijn Volkert , Kleijn Chris R. , Kreutzer Michiel T.
Published: August 2019

Thermal fluctuations have been shown to influence the thinning dynamics of planar thin liquid films, bringing predicted rupture times closer to experiments. Most liquid films in nature and industry are, however, non-planar. Thinning of such films not just results from the interplay between stabilizing surface tension forces and destabilizing van der Waals forces, but also from drainage due to curvature differences. This work explores the influence of thermal fluctuations on the dynamics of thin non-planar films subjected to drainage, with their dynamics governed by two parameters: the strength of thermal fluctuations, $\unicode[STIX]{x1D703}$, and the strength of drainage, $\unicode[STIX]{x1D705}$. For strong drainage ($\unicode[STIX]{x1D705}\gg \unicode[STIX]{x1D705}_{tr}$), we find that the film ruptures due to the formation of a local depression called a dimple that appears at the connection between the curved and flat parts of the film. For this dimple-dominated regime, the rupture time, $t_{r}$, solely depends on $\unicode[STIX]{x1D705}$, according to the earlier reported scaling, $t_{r}\sim \unicode[STIX]{x1D705}^{-10/7}$. By contrast, for weak drainage ($\unicode[STIX]{x1D705}\ll \unicode[STIX]{x1D705}_{tr}$), the film ruptures at a random location due to the spontaneous growth of fluctuations originating from thermal fluctuations. In this fluctuations-dominated regime, the rupture time solely depends on $\unicode[STIX]{x1D703}$ as $t_{r}\sim -(1/\unicode[STIX]{x1D714}_{max})\ln (\sqrt{2\unicode[STIX]{x1D703}})^{\unicode[STIX]{x1D6FC}}$, with $\unicode[STIX]{x1D6FC}=1.15$. This scaling is rationalized using linear stability theory, which yields $\unicode[STIX]{x1D714}_{max}$ as the growth rate of the fastest-growing wave and $\unicode[STIX]{x1D6FC}=1$. These insights on if, when and how thermal fluctuations play a role are instrumental in predicting the dynamics and rupture time of non-flat draining thin films.
HIV voluntary counselling and testing and behaviour changes among youths in Nigeria
Authors: Odimegwu Clifford O. , Imo Chukwuechefulam K. , Amoo Emmanuel O.
Published: August 2019

Voluntary counselling and testing (VCT) for HIV has been promoted as a strategy to prevent HIV pandemics by changing sexual behaviour. Despite the provision of VCT in countries with generalized or high-burden epidemics, including Nigeria, the extent of its influence on behavioural change remains a conjecture. The main objective of this study was to examine the influence of HIV VCT on sexual behaviour changes among youths in Nigeria. The study utilized 2013 Nigeria Demographic and Health Survey (NDHS) data. Data were analysed from a nationally representative sample drawn from 8046 females and 6031 males aged 15–24 giving a total sample of 14,077 never-married youths. Descriptive and analytical analyses were carried out, including multivariate logistic regression. The study found a low uptake of HIV VCT and regional variation in behavioural changes between female and male youths. Voluntary HIV counselling and testing was found to be a protective factor for condom use at last sex for female youths, but significantly reduced the likelihood of primary sexual abstinence for both females and males, as well as having a single sexual partner for female youths. After controlling HIV VCT with other variables, certain socioeconomic factors were found to be significantly associated with behavioural changes. Thus, the attitudes of most Nigerian youths towards voluntary HIV counselling and testing needs to be improved through socioeconomic factors for healthy sexual activity. To achieve this, government and non-governmental organizations, as well as religious leaders and policymakers, should engage in appropriate and long-term activities directed at the sexual health needs of never-married youths, through voluntary HIV counselling and testing, to encourage them to change their sexual behaviour.
The emergence of sex differences in PTSD symptoms across development: evidence from the ALSPAC cohort
Authors: Haag Katharina , Fraser Abigail , Hiller Rachel , Seedat Soraya , Zimmerman Annie , Halligan Sarah L.
Published: August 2019

Background

Cross-sectional evidence suggests females in late adolescence exhibit higher rates of post-traumatic stress symptoms (PTSS) than males and younger age groups. However, longitudinal evidence is limited, and underlying factors are not well understood. We investigated the emergence of sex differences in PTSS from childhood to adolescence in a large, longitudinal UK cohort, and tested whether these could be explained by overlap between PTSS and depressive symptoms, or onset of puberty.

Methods

Trauma exposure and PTSS were assessed at ages 8, 10, 13 (parent-report) and 15 (self-report) years in a sub-sample of 9966 children and adolescents from the ALSPAC cohort-study. Analyses of PTSS focused on those who reported potential trauma-exposure at each time-point (ranged from n = 654 at 15 years to n = 1231 at 10 years). Age at peak-height velocity (APHV) was used as an indicator of pubertal timing.

Results

There was no evidence of sex differences in PTSS at ages 8 and 10, but females were more likely to show PTSS at ages 13 (OR 1.54, p = 0.002) and 15 (OR 2.04, p = .001), even once symptoms related to depression were excluded. We found little evidence that the emergence of sex differences was related to pubertal timing (as indexed by APHV).

Conclusions

Results indicate that females show higher levels of PTSS in adolescence but not during childhood. The emergence of this sex difference does not seem to be explained by overlap with depressive symptoms, while the influence of pubertal status requires further investigation.
Orientalized Aztecs: Observations on the Americanization of Theatrical Dance
Authors: Snow K. Mitchell
Published: August 2019

The opening decades of the twentieth century saw a passing fashion for “Aztec” dancing in the vaudeville theaters of the United States. Russian classical dancers Kosloff and Fokine tapped the orientalist currents of the Ballets Russes, adopting the Aztec as superficial signs of the American. Conversely, works by Shawn and film director Cecil B. DeMille, which served as points of reference for the Russians, represented a continuation of equally orientalist attitudes toward Mexico's past, forged during the realization of the United States’ policy of Manifest Destiny. The emergence of a cadre of trained dancers from Mexico, trained by students of Kosloff and Shawn, would bring a distinctively different perspective on the presentation of their heritage to the dance stage, one that was no longer based in the imagination of an expansionist America.
Aesthetic Strategies of Trance-gression: The Politics of Bodily Scenes of Ecstasy
Authors: Huschka Sabine
Published: August 2019

Choreographic bodies are empowered by modes of expansion and transgression. Focusing on the energetic processes that lead to such empowerment, this article discusses the perceptual politics of trancelike scenes in the work of contemporary European choreographers and performers. As a body-mobilizing choreographic strategy of out-of-body and out-of-mind experiences, trance is closely linked to critical and utopian ideas, bodily transgressions, and crossed boundaries. While Mary Wigman treats trance as an incantation which contains the powers that it unleashes, contemporary choreographers like Doris Uhlich or Meg Stuart, expose the body to powers that nearly disintegrate it. As opposed to Wigman-style modernism, contemporary dance stages movement as a tremendous event that exposes performers and audiences to experiences of transgression.
The Geometry of Elliptical Probability Contours for a Fix using Multiple Lines of Position
Authors: Lionheart W.R.B. , Moses P.J.C. , Kimberling C.
Published: August 2019

Navigation methods, traditional and modern, use lines of position in the plane. Standard Gaussian assumptions about errors leads to a constant sum of squared distances from the lines defining a probability contour. It is well known these contours are a family of ellipses centred on the most probable position and they can be computed using algebraic methods. In this paper we show how the most probable position, the axes and foci of ellipses can be found using geometric methods. This results in a ruler and compasses construction of these points and this gives insight into the way the shape and orientation of the probability contours depend on the angles between the lines of position. We start with the classical case of three lines of position with equal variances, we show how this can be extended to the case where the variances in the errors in the lines of position differ, and we go on to consider the case of four lines of position using a methodology that generalises to an arbitrary number of lines.