bluuebunny/crossref_metadata_2025 huggingface dataset:
Crystal Plasticity Simulation of the AZ31B Alloy Sheet under Uniaxial Deformation Considering Grain Boundary Sliding
Authors: Li Zihan , Li Dayong , Tang Weiqin , Wang Huamiao , Peng Yinghong
Published: November 2020

The aim of present work is to develop a crystal plasticity modeling approach to integrate slip, dynamic recrystallization (DRX) and grain boundary sliding (GBS) for simulating the deformation and texture evolution of magnesium alloys deformed at the high temperature. A GBS model is developed to evaluate strain and grains’ rotation induced by GBS, and implemented into the polycrystal plasticity framework VPSC. The VPSC-DRX-GBS model can well reproduce the stress-strain curves and texture evolution. The calculated GBS contribution ratio in tension is obviously higher than in compression due to easier cavity nucleation on grain boundaries under tensile creep-aging conditions. The significantly different texture development in tension and compression deformation due to GBS is well reproduced by the proposed model.
Effects of Lubrication and Temperature on the Tribological Behavior of a Magnesium Alloy under Contact Sliding
Authors: Wu C H , Zhang L C , Qu P L , Li S Q , Jiang Z L , Wang Y
Published: November 2020

This paper aims to experimentally investigate the effects of lubrication and temperature on the tribology behavior of a magnesium alloy, AZ31B, sliding against 86CrMoV7. The effects of lubricant additives, including oil film improver and extreme pressure (phosphorous donors), on the friction coefficient and surface morphology in the sliding zone were studied. It was found that the relatively lower surface hardness of the material significantly affects the wear of the materials in the sliding zone. The lubricant with oil film improver and extreme pressure can reduce friction. Temperature rise brings about lower friction due to the lubricant additives.
Nondestructive detection of the interfacial failure of steel-polymer sandwich composites during forming process
Authors: Yang Jewook , Han Sungjin , Yu Woong-Ryul
Published: November 2020

Steel-polymer composites have low density, high specific flexural stiffness and vibration damping properties over other metal materials. However, the weak interfaces between steel and polymer sheet are the typical locations where the failure occurs. Furthermore, interfacial failure is a fatal reason of the degradation of mechanical properties. Therefore, predicting interfacial failure of the final product is an important technology in commercialization of steel-polymer composites. In this study, we built forming limit diagram (FLD) based on two different failure modes: failure of the bottom skin steel and interfacial failure between the skin steel and core polymer. Acoustic emission (AE) technique was conducted to observe the interfacial failure moment. Peak frequency was found to be the key feature to distinguish interfacial failure. Peak frequency band that indicates interfacial failure was from 300 kHz to 500 kHz. This peak frequency band made it possible to build FLD considering the interfacial failure.
Formability simulation of steel-polymer sandwiched composites considering the adhesion strength
Authors: Han S , Yang J , Yu W-R
Published: November 2020

Developed to increase the energy efficiency of automobiles, steel-polymer sandwiched composites are attracting attention due to their lightweight and multi-functionality and are being actively researched recently. In order to apply those composites to industrial fields, their formability must be investigated in order to prevent the degradation of mechanical properties of the composites during the forming process in various shapes. Therefore, experimental studies have recently been conducted to evaluate the formability of the composites. However, there are few studies to predict the formability of the composites considering the mechanical properties of core polymer and interfacial properties. In this study, formability tests were carried out for evaluating the forming limit diagram of the composites. Also, the formability test of the composites was simulated considering the viscoplastic properties of the core polymer using Arruda-Boyce model and the interfacial properties using the cohesive zone model. Finally, the effect of the interfacial adhesion on the formability of the composites was investigated, from which an optimal condition was explored for the interfacial adhesion strengths that can ensure the formability of the composites for specific applications.
Fuzzy modelling of surface scratching in contact sliding
Authors: Li Wei , Zhang Liangchi , Chen Xinping , Wu Chuhan , Cui Zhenxiang , Niu Chao
Published: November 2020

This paper presents a fuzzy modelling technique for the prediction of surface scratching problems encountered in sheet metal forming processes involving contact sliding. To generalize the contact conditions with die-sheet interactions in such processes, ball-on-disk sliding investigations, including modelling and experiment, were carried out with various ball diameters to mimic the die-contact radii effect and a range of contact loads to simulate the effect of contact stress variation experienced in forming processes. Because die-contact radius, surface roughness and contact stress changes cannot be exactly defined in a practical production process, in the modelling of the ball-on-disk configuration, ball diameter, normal load, surface roughness, sliding cycles and extent of scratching depth in a metal sheet surface were treated as fuzzy variables for the prediction. Based on the comparison between predictions with the relevant experimental measurements, it can be seen that the fuzzy modelling technique developed in this paper can predict very well the surface scratching.
Numerical analysis of the bulge test in temperature for the EN AW 6061-T6 sheet
Authors: Boyer A , Germain L , Laurent H , Neto D M , Oliveira M C
Published: November 2020

The equibiaxial expansion test allows the evaluation of the mechanical behaviour of materials on a large strain range. In this context, a bulge test device was developed which enables a fast heating stage, a uniform heating of the specimen, and the control of the temperature during the expansion phase. Although during the test, the temperature is uniform at the pole of the cap, the contact with the tools imposes a gradient along its radius. Therefore, a thermo-mechanical model of the bulge test was built in order to improve knowledge about the influence of the temperature gradient in the evaluation of the hardening behaviour at the pole of the cap. Numerical simulations of the bulge test were performed considering both isothermal and anisothermal conditions. The anisothermal conditions considered reproduce the temperature gradient observed experimentally. This enables the analysis of the impact of the thermal gradient in the stress versus strain evolution at the pole of the cap and the comparison with experimental results.
Development of inline closed-loop vibration control in progressive die stamping using finite element simulation
Authors: Steinlehner F , Ott M , Budnick D , Weinschenk A , Laumann S , Worswick M , Volk W
Published: November 2020

Modern progressive dies are increasingly equipped with integrated sensors and actuators, thus enabling an improvement of the manufacturing process and an inline monitoring of the component quality. The design of the tooling is determined at an early stage and is largely based on the desired product and the specific production stages such as blanking, forming and punching. Nevertheless, malfunctions such as strip vibrations cannot always be foreseen and may occur during operation time, which may lead to reduced component quality and in the worst case to component collision or a damage of the tooling. Therefore, complex reworking or a reduction of the stroke rate and thus lower output quantity are often necessary for a reliable and stable process. Strip vibrations are often caused by the highly dynamic transportation of the strip in the tool and can have various causes. Among others, passive tooling components such as spring-loaded, hard stop limited strip lifter can be the cause of such vibrations. Strip lifter are always necessary when three-dimensional components are produced and have to be lifted out of the die for the feeding phase. The feeding phase takes place between two strokes of the stamping process. This work is aiming for a control strategy to suppress strip vibrations in various progressive die stamping processes based on closed-loop controlled active strip lifter. These strip lifter combine the spring-loaded passive standard strip lifter with an additional PID-controlled actuator. Taking the dynamics of the flexible strip during operation into account, a Finite Element Analysis (FEA) model of a progressive die tooling system is created. For the design of the control algorithm, the FEA model is connected to an environment for model-based design in a co-simulation. This approach allows modelling the influence of arbitrary control parameter settings on the movement curve of the strip, aiming for an increased stroke rate.
Axial formation and cross-section distortion control for stretch bending based on batch simulations
Authors: Lu Kaijun , Luo Jianxi , Zou Tianxia , Li Dayong , Peng Yinghong
Published: November 2020

Stretch bending is a widely used to form long parts with a definite cross-section shape. The forming path is an effective way to eliminate the defects such as springback, distortion when the material and the die shape are determined. In this study, the stretch bending path is represented by a curve function of bending angle and stretch length. To simplify the path optimization problem, the path is represented by 4 parameters, including a newly introduced parameter of total stretch. Based on the batch simulation results, it is found that the axial springback and cross section distortion are primarily controlled by total stretch, bending angle and pre-stretch proportion. When the total stretch is determined, the different distribution schemes for pre-stretch, bending stretch and post-stretch in total stretch have a similar effect on forming quality except the schemes with extremely large proportions of pre-stretch. In most cases, with the total stretch length in growth, the axial springback decreases dramatically at first and then stays constant while the section distortion continues to rise, indicating that the optimal forming path is around the elbow point in the relationship curve of total stretch and springback angle. The optimal path is verified by experiments. It is shown that for a workpiece with determined material and die shape, the optimal path to minimize axial rebound and section distortion simultaneously does exit and the study provide an effective way to obtain it.
Springback and end flare compensation in flexible roll forming
Authors: Abeyrathna B , Ghanei S , Rolfe B , Taube R , Weiss M
Published: November 2020

Flexible roll forming enables the forming of complex automotive components from Advanced High Strength Steels (AHSS) and Ultra High Strength Steel (UHSS) but common shape defects such as end flare and springback occur and need to be compensated. In flexible roll forming a pre-cut blank is fed through a set of rolls which are computer numerically controlled (CNC) to follow the 3D contour of the part. The company, dataM Sheet Metal Solutions, have established a new 3D flexible roll forming facility at Deakin University which allows the manufacture of flexible roll formed prototypes.

In this study, Deakin’s flexible roll forming facility is employed to implement an approach to overcome springback and end flare defects in a flexible roll formed automotive component of variable width. To do this, the flexible roll forming process is simulated using the commercial software package Copra FEA. Non-uniform springback due to end flare is observed and a variable overbending approach developed and implemented to overcome this defect. Experimental validation is performed on Deakin’s flexible roll forming facility and the results suggest that the flexible overbending approach can be used to control final shape in flexibly roll formed components.
Deformation characteristics in 3D free-bending forming of complex spiral tubes
Authors: Abd El-Aty A , Wei W , Guo X , Wang H , Tao J , Chen H , Qin Y
Published: November 2020

Free-bending is a novel bending technology suitable for tube and profile bending. It can achieve accurate bending of tubes or profiles with different bending radii without die. In current study, a new theoretical analysis of a spiral tube formed by 3D free-bending is proposed to reveal the relationship between the spiral tube and the parameters of free-bending forming technology. The results obtained from the proposed theoretical analysis were compared with those achieved from FE modelling and experimentation. The maximum error of forming was less than 7%, which verified the accuracy and the reliability of the proposed theoretical model. The forming limits of the spiral tubes based on 3D free-bending were explored. It was noticed that the spiral diameter was mainly influenced by the eccentricity and the distance between the center of the bending die and the front end of the guide mechanism in the Z–direction (distance A). Furthermore, the spiral diameter is inversely proportional to the eccentricity, and directly proportional to the distance A. In addition, the screw pitch is mainly influenced, and directly proportional to the spiral diameter and the single spiral circle swing angle of the spherical bearing.
A simple device to measure bend limit of sheet metals
Authors: Deole A , Etxebarria N , Mendiguren J , Ilinich A , Weiss M
Published: November 2020

The analysis of bend fracture limits of sheet metals is important for the automotive industry. For high and mid-ductility materials, current methods are often unreliable due to the difficultly of detecting the initiation of a crack on the outer surface of the bend. Sophisticated techniques that rely on the strain evolution in the material are capable to detect the cracks and establish the bend limits using digital image correlation (DIC) strain measurement systems. However, these techniques are complex and sometimes impractical for industrial use. This study uses a simplified bend test technique that uses optical image processing to detect crack initiation to then determine the bend limits of aluminum alloys using a modified angled line method (MALM). The findings of this study indicate that the optical method is inconsistent in detecting the crack initiation and likely to result in a large deviation in detected the bend limits.
Crystal plasticity as complementary modelling technique for improved simulations results of anisotropic sheet metal behaviour in forming processes
Authors: Hirsiger Sebastian , Berisha Bekim , Hippke Holger , Hora Pavel
Published: November 2020

The accuracy of the simulation results in terms of metal sheet forming strongly depends on the capability of modelling the anisotropic material behaviour. In addition, predictive capabilities of the models are strongly influenced by the way how the constitutive model parameters are calibrated. Macroscopic models lean towards to become more complex in order to map the material behaviour more precisely. As consequence the amount and complexity of the experiments is increasing as well. In addition, it is well known that, some of the experiments, for example the equibiaxial compression test, are difficult to perform and therefore, a reasonable coupling of crystal plasticity (CP) modelling and macroscopic models is proposed. It is worth to mention that, in the domain of CP, arbitrary load cases are possible and therefore, any stress ratio of the yield criterion can be used for calibration. Prediction of anisotropic material behaviour of AA6016-T4 and DC05 sheets based on CP simulations were previously presented and compared with the macroscopic Yld2000-2d model. Their data set is now used for the calibration of the parameters of the macroscopic model, where in contrast to the classical procedure, the exponent of the yield locus is defined as a fitting parameter. The strain distributions predicted by the models have been compared with DIC-measurements of Nakajima samples. The predictive capabilities of the CP-based fitting procedure, compared to the classical fitting, are highlighted. Additionally, a comparison of the strain distribution prediction between all model variants is performed on a cruciform shaped deep drawing part. It underlines the importance of the correct prediction of the yield normal, as it is given by the crystal plasticity computation.
On the design of an air-cooling system of an IC engine block made from sheet metal
Authors: Date Prashant P , Dhonde Shubham P
Published: November 2020

The cast and machined automotive cylinder block and the cylinder head serve to locate and hold the combustion cylinders in place, provide for cooling channels for the combustion cylinders and damp out vibrations, besides housing allied components needed for combustion. In the present work, the authors attempt to redesign the cooling system of the engine block for manufacture from sheet metal, and reduce its weight. It is proposed to have an air-cooling system around each of the combustion cylinders using a finned cooling cylinder rotating concentric with respect to the combustion cylinder with a coolant occupying the annular gap between the combustion cylinder and the cooling cylinder. The peculiar design enables hotter air to enter the combustion cylinder thereby increasing the expected thermal efficiency and power output, besides enhancing the quality of air-fuel mixing. Manufacture of the engine block from sheet metal involves embossing flow channels into thin sheets for the coolant, or machining such channels in thick sheets, folding them over, brazing the flat surfaces between channels and brazing the fin to the periphery of the cooling cylinder.
A new technique for characterising mechanical properties of materials under hot stamping conditions
Authors: Zhang R , Lin J , Shi Z , Shao Z
Published: November 2020

In order to characterise mechanical properties of materials (e.g. formability) under hot stamping conditions, significant efforts have been made to the development of the biaxial tensile testing method using cruciform specimens. However, no method for necking strain determination and no cruciform specimen design have been widely accepted. In this study, a new technique for characterising mechanical behaviour of materials under hot stamping conditions has been proposed. It includes two main parts: 1) a novel spatio-temporal method for determining necking and fracture strains, and 2) a cruciform specimen design for formability evaluation using biaxial testing method. In the first part, the theoretical base of the novel spatio-temporal method has been discussed, and the method has been validated by applying to uniaxial tensile tests on AA6082 specimens. The method has also been compared with several existing popular methods, in the determination of limit strain at onset of localised necking. It is found that the novel method has greater simplicity, stability and accuracy for the determination of localised necking strain. In the second part, a proposed cruciform specimen of AA5754 has been tested under the equi-biaxial tension, and both the necking initiation location and the strain path at the location where necking initiates, have been analysed. Furthermore, the novel spatio-temporal method has been applied to the biaxial tensile test for the determination of necking and fracture strains. The results show that the designed cruciform specimen enables to initiate fracture at the centre of the specimen and realisation of linear strain path under equi-biaxial tension.
Forming limit of sheet metal in cylindrical deep drawing with a conical die
Authors: Xin Luo , Evsyukov C A , Zhongqi Yu
Published: November 2020

It is well-known that the use of a conical die in cylindrical deep drawing can enhance the formability compared with conventional process. The most commonly observed failure mode in the process is fracture near the punch corner or wrinkling in the flange region. In order to obtain the limiting drawing ratio (LDR), a cylindrical deep drawing including only the conical die and flat punch is discussed based on numerical simulation in the paper. A finite element model for the deep drawing with a conical die is developed, and the accuracy of the model is verified by experiments results. The investigation shows that in the cylindrical deep drawing with a conical die, the types of failure above, which can obtain for thinner sheet materials, are obviously related to the sheet thickness and the conical angle, and the optimum conical angle is also found.
Experimental Analysis of Warping Defects in Chain-die Forming Variable-width Profiles
Authors: Liang Zhenye , Zou Tianxia , Li Dayong , Xiao Hua , Shi Lei , Ding Shichao , Peng Yinghong
Published: November 2020

Chain-Die forming is an emerging gradual forming technology suitable to fabricate advanced high strength steel (AHSS) products. In this paper, a variable-width product was designed, and the feasibilities of chain-die forming were investigated with experiments. The results show that chain-die forming is capable of manufacturing AHSS variable-width products with good precision. However, warping defects were found in the chain-die formed variable-width products. Meanwhile, web-warping and flange-warping show a similar trend for the designed variable-width profile, and the maximum deviation of warping was quantitatively analyzed. The occurrences of warping defects are ascribed to the insufficient tensile or compressive deformation, and both web area and flange area of hat profile tend to rotate to compensate for the geometrically necessary longitudinal strain.
ADE surfaces and their moduli
Authors: Alexeev Valery , Thompson Alan
Published: November 2020

We define a class of surfaces corresponding to the

A
D
E

ADE

root lattices and construct compactifications of their moduli spaces as quotients of projective varieties for Coxeter fans, generalizing Losev-Manin spaces of curves. We exhibit modular families over these moduli spaces, which extend to families of stable pairs over the compactifications. One simple application is a geometric compactification of the moduli of rational elliptic surfaces that is a finite quotient of a projective toric variety.
Strengthening the Ties That Bind: An Evaluation of Cross-disciplinary Communication Between Invasion Ecologists and Biological Control Researchers in Entomology
Authors: Schulz Ashley N , Lucardi Rima D , Marsico Travis D
Published: November 2020

To control non-native species, resource managers may import and introduce biocontrol agents. Like accidentally introduced insects, biocontrol agents must overcome several abiotic and biotic obstacles to establish successfully. They can also have varying efficacy and negative or positive impacts on native species and ecosystems. Given the similarities between accidentally introduced insects and biocontrol agents, researchers studying these organisms can more effectively communicate and actively link data to improve overall understanding and management of non-native species within the framework(s) of invasion theory. To assess interdisciplinarity between invasion ecologists and biocontrol practitioners that study insects in forests, we identified 102 invasion ecology and 90 biocontrol articles published from 2006 to 2018. These articles helped us determine which broad disciplines (invasion ecology, biocontrol, other control, other ecological, and nonecological) and publication formats (e.g., journals and books) the authors cited most. We found 1) invasion ecologists primarily cite other invasion ecology research; 2) biocontrol researchers cite biocontrol and invasion ecology research; 3) both disciplines primarily cited peer-reviewed journal articles; and 4) there was 65–70% overlap in the top 20 journals cited in primary invasion ecology and biocontrol literature. Though we found some cross-communication, it is currently mostly unidirectional, whereby invasion ecology informs biocontrol. We identify and discuss three areas—1) ecological principles governing success or failure of introduced species, 2) the invasion process, and 3) negative impacts on native species—for which the disciplines possess substantial overlap to demonstrate that biocontrol agents can provide invasion ecologists with an unconventional model to study the mechanisms of species invasion.
Does the Temporal Pattern of Moving to a Higher-Quality Neighborhood Across a 5-Year Period Predict Psychological Distress Among Adolescents? Results From a Federal Housing Experiment
Authors: Schmidt Nicole M , Glymour M Maria , Osypuk Theresa L
Published: November 2020

Using data from the Moving to Opportunity (MTO) experiment (1994–2002), this study examined how a multidimensional measure of neighborhood quality over time influenced adolescent psychological distress, using instrumental variable (IV) analysis. Neighborhood quality was operationalized with the independently validated 19-indicator Child Opportunity Index (COI), linked to MTO family addresses over 4–7 years. We examined whether being randomized to receive a housing subsidy (versus remaining in public housing) predicted neighborhood quality across time. Using IV analysis, we tested whether experimentally induced differences in COI across time predicted psychological distress on the Kessler Screening Scale for Psychological Distress (n = 2,829; mean β = −0.04 points (standard deviation, 1.12)). The MTO voucher treatment improved neighborhood quality for children as compared with in-place controls. A 1-standard-deviation change in COI since baseline predicted a 0.32-point lower psychological distress score for girls (β = −0.32, 95% confidence interval: −0.61, −0.03). Results were comparable but less precisely estimated when neighborhood quality was operationalized as simply average post–random-assignment COI (β = −0.36, 95% confidence interval: −0.74, 0.02). Effect estimates based on a COI excluding poverty and on the most recent COI measure were slightly larger than other operationalizations of neighborhood quality. Improving a multidimensional measure of neighborhood quality led to reductions in low-income girls’ psychological distress, and this was estimated with high internal validity using IV methods.
Mining in Rajasthan—a Quagmire for Policy, Practice and People
Authors: Basu Pekham
Published: November 2020

People, practitioner and policy-makers share a tumultuous relationship fraught with expectations and frustrations. In this article, the author delves into her own experience of working with mineworkers, subaltern voices and the issue of mining in Rajasthan, India, and the role of civil society in the form of non-government organisation (NGO). The article traces the challenges of mobilising people for collective action, engaging with policy-makers and the constraints of a formal structure of an NGO. It focusses on the mineworkers engaged in minor mineral extraction and employed as informal labour. The article begins with familiarising readers with the situation of mineworkers and administration of minor mineral mining. In the next section, a brief overview on social work practice using the genesis of the NGO is provided where the author worked and engages with even today. The final section, explains the challenges in collective action for policy-making. The author has used the word organisations, NGO and social worker interchangeably, as also the words mineworkers, community and service users.
Face Tuning in Depression
Authors: Kubon Julian , Sokolov Alexander N , Popp Rebecca , Fallgatter Andreas J , Pavlova Marina A
Published: November 2020

The latest COVID-19 pandemic reveals that unexpected changes elevate depression bringing people apart, but also calling for social sharing. Yet the impact of depression on social cognition and functioning is not well understood. Assessment of social cognition is crucial not only for a better understanding of major depressive disorder (MDD), but also for screening, intervention, and remediation. Here by applying a novel experimental tool, a Face-n-Food task comprising a set of images bordering on the Giuseppe Arcimboldo style, we assessed the face tuning in patients with MDD and person-by-person matched controls. The key benefit of these images is that single components do not trigger face processing. Contrary to common beliefs, the outcome indicates that individuals with depression express intact face responsiveness. Yet, while in depression face sensitivity is tied with perceptual organization, in typical development, it is knotted with social cognition capabilities. Face tuning in depression, therefore, may rely upon altered behavioral strategies and underwriting brain mechanisms. To exclude a possible camouflaging effect of female social skills, we examined gender impact. Neither in depression nor in typical individuals had females excelled in face tuning. The outcome sheds light on the origins of the face sensitivity and alterations in social functioning in depression and mental well-being at large. Aberrant social functioning in depression is likely to be the result of deeply-rooted maladaptive strategies rather than of poor sensitivity to social signals. This has implications for mental well-being under the current pandemic conditions.
The Stumbling Balance between Public Health and Privacy amid the Pandemic in China
Authors: Kui Shen
Published: November 2020

In China, to fight against COVID-19, a variety of high- and low-tech methods have been created and applied to find and monitor people confirmed or suspected to have COVID-19 and their close contacts. Such mass monitoring may have the effect of containing and managing the pandemic, but it has brought about prevalent concerns of privacy. Undoubtedly, China is confronted with fulfilling the task of public health surveillance while, at the same time, protecting personal privacy. However, there are three factors that have caused these balancing efforts to falter. The first factor is the lack of strong and solid legal foundations to authorize and control the surveillance while giving sufficient support for personal privacy. The second factor is the huge social mobilization that entails the involvement of a large number of different entities and individuals in the mass surveillance, for whom the general principles of privacy protection proposed by public authorities and academia may not be well understood and/or may be difficult to follow in practice. The third factor is the collectivist thinking and obedience to, and in many cases reverence for, the authority that is deeply entrenched in Chinese culture and easily overwhelms the individualism-oriented modern privacy culture. To get rid of these handicaps in a short time and, hence, to strengthen privacy would be an extravagant hope. However, a landmark piece of legislation on privacy and personal information protection and other supporting regulations in the near future are what we need most. In any event, the current surveillance should not be a ‘new normal’.
Atrial Fibrillation and the Prognostic Performance of Biomarkers in Heart Failure
Authors: Tan Eugene S J , Chan Siew-Pang , Liew Oi-Wah , Chong Jenny P C , Leong Gerard K T , Yeo Daniel P S , Ong Hean-Yee , Jaufeerally Fazlur , Yap Jonathan , Sim David , Ng Tze-Pin , Ling Lieng-Hsi , Lam Carolyn S P , Richards Arthur M
Published: November 2020

Background

Consideration of circulating biomarkers for risk stratification in heart failure (HF) is recommended, but the influence of atrial fibrillation (AF) on prognostic performance of many markers is unclear. We investigated the influence of AF on the prognostic performance of circulating biomarkers in HF.

Methods

N-terminal pro-B-type natriuretic peptide (NT-proBNP), mid-regional-pro-atrial natriuretic peptide, C-type natriuretic peptide (CNP), NT-proCNP, high-sensitivity troponin-T, high-sensitivity troponin-I, mid-regional-propeptide adrenomedullin, co-peptin, growth differentiation factor-15, soluble Suppressor of Tumorigenicitiy (sST2), galectin-3, and procalcitonin plasma concentrations were measured in a prospective, multicenter study of adults with HF. AF was defined as a previous history of AF, and/or presence of AF/flutter on baseline 12-lead electrocardiogram. The primary outcome was the composite of HF-hospitalization or all-cause mortality at 2 years.

Results

Among 1099 patients (age 62 ± 12years, 28% female), 261(24%) patients had AF. Above-median concentrations of all biomarkers were independently associated with increased risk of the primary outcome. Significant interactions with AF were detected for galectin-3 and sST2. In considering NT-proBNP for additive risk stratification, sST2 (adjusted hazard ratio [AHR]1.85, 95%confidence interval [C.I.] 1.17-2.91) and galectin-3 (AHR1.85, 95%C.I. 1.09-2.45) were independently associated with increased primary outcome only in the presence of AF. The prognostic performance of sST2 was also stronger in AF for all-cause mortality (AF: AHR2.82, 95%C.I. 1.26-6.21; non-AF: AHR1.78, 95% C.I. 1.14-2.76 without AF), while galectin-3 predicted HF-hospitalization only in AF (AHR1.64, 95%C.I. 1.03-2.62).

Conclusions

AF modified the prognostic utility of selected guideline-endorsed HF-biomarkers. Application of markers for prognostic purposes in HF requires consideration of the presence or absence of AF.

Clinical trial registration

ACTRN12610000374066
Mid-elevational Peaks in Diversity of Ground-dwelling Arthropods with High Species Turnover on the Colorado Plateau
Authors: Uhey Derek , Haubensak Karen , Hofstetter Richard
Published: November 2020

Patterns of biodiversity along elevational gradients elucidate how climate shapes biological communities and help predict ecosystem responses to environmental change. Arid elevational gradients are particularly interesting because temperature limitations at high elevations and precipitation limitations at low elevations cause mid-elevation peaks in diversity. Ground-dwelling arthropods form highly diverse communities but few studies document elevational patterns of their full diversity. Here we investigate the elevational patterns of ground-dwelling arthropods in northern Arizona on the Colorado Plateau, an arid and understudied region in the United States. We sampled seven sites along an elevation gradient from 1,566 to 2,688 m corresponding to a difference of 6.5°C average annual temperature and 620 mm average annual precipitation. We captured 16,942 specimens comprising 169 species, mostly ants and beetles, and discovered a new ant species. First- and second-order elevation terms significantly correlated to multiple measures of arthropod α and β diversity. Arthropod abundance, richness, and Shannon-Wiener diversity index peaked at mid-elevations, with functional groups (i.e., omnivores, predators, detritivores, and herbivores) showing similar patterns. Community composition varied significantly across the gradient, correlated with changes in elevation, and was driven by shifts of ants dominating low- to mid-elevations, to beetles dominating high-elevations. Dissimilarity among sites was driven by high species turnover with 59% of species exclusive to a single site, whereas nestedness among sites was low except at the lowest elevation site. High rates of turnover and elevation-dependent communities suggest that ground-dwelling arthropods are highly vulnerable to environmental change, particularly at lower elevations in arid regions.
Conventional Soil Management May Promote Nutrients That Lure an Insect Pest to a Toxic Crop
Authors: Schmidt-Jeffris Rebecca A , Moretti Erica A , Wickings Kyle , Wolfin Michael S , Northfield Tobin D , Linn Charlie E , Nault Brian A
Published: November 2020

Slow and consistent nutrient release by organic fertilizers can improve plant nutrient balance and defenses, leading to herbivore avoidance of organically managed crops in favor of conventional crops with weaker defenses. We propose that this relative attraction to conventional plants, coupled with the use of genetically modified, insecticidal crops (Bt), has created an unintentional attract-and-kill system. We sought to determine whether Bt and non-Bt corn Zea mays L. plants grown in soil collected from five paired organic and conventional fields differed in attractiveness to European corn borer [Ostrinia nubilalis (Hübner)] moths, by conducting ovipositional choice and flight tunnel assays. We then examined the mechanisms driving the observed differences in attraction by comparing soil nutrient profiles, soil microbial activity, plant nutrition, and plant volatile profiles. Finally, we assessed whether European corn borer abundance near corn fields differed based on soil management. European corn borer preferred plants grown in conventional soil but did not discriminate between Bt and non-Bt corn. Organic management and more alkaline soil were associated with an increased soil magnesium:potassium ratio, which increased plant magnesium, and were linked to reduced European corn borer oviposition. There was an inconsistent trend for higher European corn borer moth activity near conventional fields. Our results extend the mineral balance hypothesis describing conventional plant preference by showing that it can also improve attraction to plants with genetically inserted toxins. Unintentional attract (to conventional) and (Bt) kill is a plausible scenario for pest declines in response to Bt corn adoption, but this effect may be obscured by variation in other management practices and landscape characteristics.
Ephemeral are Gay Gulps of Laughter’: P. B. Shelley, Louis Macneice, and the Ambivalence of Laughter
Authors: Davis Amanda Blake
Published: November 2020

Ambivalence is the hallmark of Shelley’s poetry, but the ambivalence of Shelley’s often underappreciated wit remains a relatively uncharted area of critical exploration. The characterization of laughter as ‘heartless fiend’ – or ‘heartless friend’ – in Shelley’s sonnet ‘To Laughter’ underscores this very ambivalence while also spotlighting the sociality of laughter. Drawing upon the ancient Greek ambiguities of laughter as socially divisive and socially integrative, laughter in Shelley’s poetry vacillates between ostracizing bursts and harmonizing glee. This essay explores the ambivalence of Shelleyan laughter and its echo in the poetry of Louis MacNeice, prompted by the modern poet’s early interest in ‘a comparison of Shelley & Nietzsche & a deification of laughter’. MacNeice’s realist leanings remain coloured by Romantic predispositions throughout his career. With attention to Shelley and MacNeice’s Classical backgrounds, this essay reveals how Shelleyan laughter echoes throughout MacNeice’s poetry and, in its ambivalence, unveils the extent to which identity is unfixed for both poets.
Persuadable perceptions: the effect of media content on beliefs about corruption
Authors: Rizzica Lucia , Tonello Marco
Published: November 2020

We study the impact of news content on individuals’ perceptions about corruption. To this purpose, we combine individuals’ beliefs about the likelihood that corruption events may occur in everyday life, as obtained from questions introduced in a large household survey, with their as-good-as-random exposure to corruption-related news on the date of the interview. Results show that a 1 SD increase in the number of corruption news items raises corruption perceptions by 3.5%. Consistently with a mechanism of persuasion, perceptions respond mainly to news not related to specific corruption events rather than to those reporting on arrests, investigations or convictions.
Seismicity clusters in Central Chile: investigating the role of repeating earthquakes and swarms in a subduction region
Authors: Valenzuela-Malebrán Carla , Cesca Simone , Ruiz Sergio , Passarelli Luigi , Leyton Felipe , Hainzl Sebastian , Potin Bertrand , Dahm Torsten
Published: November 2020

Seismicity along subduction interfaces is usually dominated by large main-shock–aftershock sequences indicative of a continuum distribution of highly coupled large asperities. In the past decades, however, the increased resolution of seismic catalogues at some subduction zone seems to indicate instead a more complex rheological segmentation of the interface. Large and megathrust earthquake ruptures seem interspersed among regions of low seismic coupling and less stress buildup. In this weaker zone, the strain is primarily released via a combination of moderate-size swarm-like seismicity and aseismic slip. Along the Chilean subduction zone, the densification of the seismic network allowed for the identification of localized seismic clusters, some of them appearing in the form of swarms before megathrust earthquakes. The origin and driving processes of this seismic activity have not yet been identified. In this study, we follow a systematic approach to characterize the seismicity at two persistent clusters in Central Chile, one located offshore Navidad and one inland, at ∼40 km depth beneath Vichuquén, which occurred throughout ∼20 yr. We investigated these clusters, by deriving high-resolution hypocentral locations and moment tensors and performing a detailed analysis of spatio-temporal patterns, magnitude and interevent time distributions of the clustered earthquakes. Both clusters are characterized by weak to moderate seismicity (below Mw 6) and stand out as clear seismicity rate and Benioff strain anomalies. At the Navidad cluster, seismicity occurs in the form of swarms, with a characteristic duration of 2–7 d and location and thrust mechanisms compatible with activity on the slab interface. Conversely, we find at Vichuquén activity dominated by thrust earthquakes occurring as repeaters on the slab interface, with a slip rate of approximately ∼5.0 cm yr−1. We attribute these clusters to local features of the subducting plate: the Navidad swarms are likely driven by repeated high pore pressure transients along a pre-fractured patch of the slab, while the seismicity at the Vichuquén cluster is interpreted as the result of a subducting seamount. Both clusters have been active before and after the Mw 8.8 Maule earthquake and persisted afterwards with the seismicity decay following the Omori law. These interactions are especially evident for the Vichuquén cluster, where the seismicity rate increased considerably after the Maule earthquake and continues to be an area of clearly elevated seismicity rate compared to its surroundings.
Innovation, upgrading, and governance in cross-sectoral global value chains: the case of smartphones
Authors: Lee Joonkoo , Gereffi Gary
Published: November 2020

The fourth industrial revolution challenges the existing understanding of innovation and upgrading in the global economy. It blurs traditional sectoral boundaries based on distinctive products and technologies and calls into question a traditional global value chain (GVC) perspective, which, similar to the sectoral systems of innovation approach, examines innovation and upgrading from a sector-based orientation. Building upon the recent reformulation and extension of GVC governance theory, this article proposes the notion of cross-sectoral GVC governance to capture the new stage of platform-based industrial development. It specifies the conceptual dimensions of cross-sectoral GVC governance in terms of the mode of governance (i.e., driving, linking, and normalizing), the overall GVC structure in terms of polarity, and firm strategies of managing GVCs. The proposed framework is illustrated using the case of smartphones as a platform product, focusing on four lead firms—Samsung, Apple, Huawei, and Google—to showcase divergent firm strategies for governing cross-sectoral linkages related to innovation and upgrading.
The Promise and Perils of Urban Land Restitution in Latvia
Authors: Rowen Jamie , Snipe Arta
Published: November 2020

ABSTRACT∞

In this article we address the transitional justice policy of restitution in kind with a case study of urban land reform in Latvia. Contributing to scholarship on the challenge of property reforms after generations of dispossession, we examine the economic, social and political meanings of property restitution in this post-Soviet context. Using process-tracing techniques to examine the creation and implementation of Latvia’s policy in the aftermath of independence from the Soviet Union, we illustrate specific challenges of restitution in kind where property changed through the construction of new buildings occupied by tenants. Financial disputes between landowners and tenants map on to ethnic and political divisions in Latvia, and a policy once seen as a remedy is now in need of a remedy.
Bundles with Non-multiplicative Â-Genus and Spaces of Metrics with Lower Curvature Bounds
Authors: Frenck Georg , Reinhold Jens
Published: November 2020

We construct smooth bundles with base and fiber products of two spheres whose total spaces have nonvanishing $\hat{A}$-genus. We then use these bundles to locate nontrivial rational homotopy groups of spaces of Riemannian metrics with lower curvature bounds for all ${{\operatorname{Spin}}}$ manifolds of dimension 6 or at least 10, which admit such a metric and are a connected sum of some manifold and $S^n \times S^n$ or $S^n \times S^{n+1}$, respectively. We also construct manifolds $M$ whose spaces of Riemannian metrics of positive scalar curvature have homotopy groups that contain elements of infinite order that lie in the image of the orbit map induced by the push-forward action of the diffeomorphism group of $M$.
Rosmarinus officinialisL. (Lamiales: Lamiaceae), a Promising Repellent Plant for Thrips Management
Authors: Li Xiao-Wei , Zhang Zhi-Jun , Hafeez Muhammad , Huang Jun , Zhang Jin-Ming , Wang Li-Kun , Lu Yao-Bin
Published: November 2020

A number of thrips species are among the most significant agricultural pests globally. Use of repellent intercrop plants is one of the key components in plant-based ‘push–pull’ strategies to manage pest populations. In this study, the behavioral responses of three thrips species, Frankliniella occidentalis (Pergande), Frankliniella intonsa (Trybom), and Thrips palmi Karny (Thysanoptera: Thripidae) to Rosmarinus officinalis were investigated in Y-tube olfactometer bioassays and cage experiments. In addition, the major volatile compounds from rosemary were identified and the effect of the individual compounds on thrips behavior was evaluated. Females and males of the three thrips species were significantly repelled by the volatiles from cut rosemary leaves. The presence of rosemary plants significantly reduced settlement of females of the three thrips species and eggs laid by F. occidentalis females on target host plants. In total, 47 compounds were identified in the volatiles collected from the cut leaves of rosemary plants. The responses of the three thrips species to 10 major volatile compounds showed significant differences. However, α-pinene, the most abundant volatile, was repellent to F. occidentalis and F. intonsa. Eucalyptol, the second most abundant volatile, showed significant repellent activity to all the three thrips species. Our findings showed that rosemary is a promising repellent plant against the three thrips pests we tested, which could be a good candidate for ‘push’ plants in plant-based ‘push–pull’ strategies. The identified volatile compounds that accounted for the repellent activity could be developed as repellents for sustainable thrips management.