bluuebunny/crossref_metadata_2025 huggingface dataset:
Glass Transition Phenomenon for Conjugated Polymers
Authors: Qian Zhiyuan , Cao Zhiqiang , Galuska Luke , Zhang Song , Xu Jie , Gu Xiaodan
Published: April 2019

Conjugated polymers are emerging as promising building blocks for a broad range of modern applications including skin‐like electronics, wearable optoelectronics, and sensory technologies. In the past three decades, the optical and electronic properties of conjugated polymers have been extensively studied, while their thermomechanical properties, especially the glass transition phenomenon which fundamentally represents the polymer chain dynamics, have received much less attention. Currently, there is a lack of design rules that underpin the glass transition temperature of these semirigid conjugated polymers, putting a constraint on the rational polymer design for flexible stretchable devices and stable polymer glass that is needed for the devices’ long‐term morphology stability. In this review article, the glass transition phenomenon for polymers, glass transition theories, and characterization techniques are first discussed. Then previous studies on the glass transition phenomenon of conjugated polymers are reviewed and a few empirical design rules are proposed to fine‐tune the glass transition temperature for conjugated polymers. The review paper is finished with perspectives on future directions on studying the glass transition phenomena of conjugated polymers. The goal of this perspective is to draw attention to challenges and opportunities of controlling, predicting, and designing polymeric semiconductors, specifically to accommodate their end use.
Melting, Solidification, and Crystallization of a Thermoplastic Polyurethane as a Function of Hard Segment Content
Authors: Stribeck Almut , Eling Berend , Pöselt Elmar , Malfois Marc , Schander Edgar
Published: April 2019

Thermoplastic polyurethanes (TPU) with varying hard segment contents (HSC) are monitored during melting and solidifying (, Tmax = 220 ° C) by small‐angle and wide‐angle X‐ray scattering (WAXS and SAXS). Hard segments: MDI/BD. Soft segments: PTHF1000. The neat materials are injection‐molded, having small amorphous hard domains (chord length ). Results indicate complexity of morphology changes. For example, crystals are predominantly produced in freshly segregated, sufficiently large hard domains, while the temperature decreases slowly enough. After the thermal treatment, only the materials with HSC >∼ 35% show sharp Bragg peaks and larger hard domains (). When heated, small domains melt, but crystallization in the remaining large domains is not detected. Upon cooling, large agglomerates segregate first, which crystallize immediately. Segregation starts for HSC = 42% at 160 °C and for HSC = 75% at 210 °C. When HSC ≤ 30%, the morphologies before and after are similar, but afterward, many hard blocks are dissolved in the soft phase at the expense of the hard domain fraction. In heating and cooling the melts, multiple homogenization and segregation processes are observed, which are explained by the agglomeration of hard blocks of different lengths in the colloidal fluid.
The Influence of Al2O3 and TiO2 Additives on the Electrical Resistivity of Epoxy Resin‐Based Composites at Low Temperature
Authors: Eker Yasin Ramazan , Özcan Muciz , Özkan Ali Osman , Kırkıcı Hülya
Published: April 2019

Electrical insulation is a major security problem in aerospace applications where temperature can reach relatively low values. Epoxy resins are well known as easily formable dielectric materials and can be used to prepare complex insulator parts. In this study, the electrical performance of bisphenol A/epichlorohydrin epoxy resin matrix‐based nanocomposites containing 1, 3, or 6 wt% titanium oxide (TiO2) or aluminium oxide (Al2O3) nanofillers are investigated. Composites are characterized with thermogravimetric analysis, scanning electron microscopy‐coupled electron dispersive spectroscopy, and confocal Raman spectroscopy. Furthermore, the role of additives and their ratio on the resistivity performance of the composites are evaluated from 77 to 500 K by applying a direct current voltage from 1 to 20 V. It is observed that the electrical properties of the matrix are directly influencing the insulation performance of the nanocomposite. For example, the abrupt decrease at 370 K of the positive temperature coefficient of the resin for all nanocomposites. It is found that the most resistive composite contains 3 wt% TiO2 nanoparticles with a value above 3.7.1010 Ω from 77 to 370 K at 20 V. As a result, this work gives information on to the choice of appropriate insulator materials in extreme working conditions.
Anhydride Cured Bio‐Based Epoxy Resin: Effect of Moisture on Thermal and Mechanical Properties
Authors: Anusic Andrea , Resch‐Fauster Katharina , Mahendran Arunjunai Raj , Wuzella Günter
Published: April 2019

This paper describes the development of a novel thermoset based on epoxidized hemp seed oil. The optimization of the hardener (anhydride) and crosslinking accelerator (2‐ethylimidazol) concentration as well as the curing parameters are discussed in detail. The optimized material exhibits a bio‐based carbon portion of 57.5 wt% and represents an innovative and sustainable substitute for fully petrochemical‐based resins in terms of thermal and mechanical performance characteristics. However, also a major challenge with regard to practical applications of (bio‐based) thermosets with anhydride curing agent thermosets is identified and addressed: the sensitivity to moisture absorption both during curing and in the fully cured state.
The Effect of Epoxidation on Strain‐Induced Crystallization of Epoxidized Natural Rubber
Authors: Zhang Xi , Niu Kaijing , Song Weixiao , Yan Shouke , Zhao Xiuying , Lu Yonglai , Zhang Liqun
Published: April 2019

The effect of epoxidation on strain‐induced crystallization (SIC) of epoxidized natural rubber (ENR) and mechanism are studied with synchrotron radiation wide‐angle X‐ray diffraction (SR‐WAXD) and polarized infrared spectroscopy (P‐IR). WAXD results reveal that appropriate epoxidation, for example, ENR‐25 epoxidized with ≈25% isoprene units, can unexpectedly enhance the SIC of natural rubber (NR), resulting in the improvement of tear resistance. On the other hand, exorbitant epoxidation, for example, ENR‐40 epoxidized with ≈40% isoprene units, depresses the SIC and weakens the mechanical properties of NR remarkably. P‐IR studies reveal that epoxidation can promote the orientation of chain segments along the stretching direction, which plays a determining role on SIC of NR. Accordingly, hierarchical multiscale schematic models are proposed. This insight into epoxidation on SIC of ENR strongly suggests that ENR with appropriate epoxidation degree is a promising candidate material for the fabrication of high‐performance engineering rubber products.
First Observations of Long-Distance Migration in a Large Skate Species, the Winter Skate: Implications for Population Connectivity, Ecosystem Dynamics, and Management
Authors: Frisk Michael G. , Shipley Oliver N. , Martinez Christopher M. , McKown Kim A. , Zacharias Joshua P. , Dunton Keith J.
Published: April 2019

The overexploitation and decline of groundfish populations throughout the 1980s and 1990s resulted in a regime shift on Georges Bank and southern New England, which was characterized by subsequent exponential increases in the observed biomass of Winter Skate Leucoraja ocellata in the region. Recent work suggested that the rate of the Winter Skate biomass increase cannot be fully explained by internal population dynamics of a population without immigration from other regions and/or populations and that adult-mediated population connectivity (AMPC) with neighboring regions is required to fully explain biomass trends. Despite this, no evidence of long-distance dispersal has been observed for Winter Skate, with individuals assumed to display high endemicity to specific regions of the continental shelf. Annual movements of 58 Winter Skate captured off coastal New York were examined using passive acoustic telemetry, revealing seasonal long-distance dispersal capabilities exceeding 1,000 km. In total, 88,783 unique acoustic detections were observed. Telemetered individuals had an average time at liberty of 199.73 d and collectively traveled 17,576.9 km. Individuals tended to migrate south during summer/fall and north during winter/spring. Movement rates of individuals averaged 9.88 km/d (95% confidence interval = 9.25–10.92 km/d) but ranged from 0.13 to 41.38 km/d. An additional 51 recaptured Winter Skate from a total of 3,416 marked with Floy tags suggested greater offshore movement than was observed in acoustically tagged individuals. Our results illustrate that the Winter Skate is a highly mobile species that moves extensively throughout its large geographic range, consistent with its observed ability to rapidly invade neighboring habitat via AMPC. This study has important implications for our understanding of the role of Winter Skate in northwest Atlantic communities and for management strategies therein.
Age, Growth, Natural Mortality, and Reproductive Seasonality of Knobbed Porgy from Southeastern United States Waters
Authors: Burton Michael L. , Potts Jennifer C. , Poholek Ariel J. , Ostrowski Andy , Page Jordan
Published: April 2019

The Knobbed Porgy Calamus nodosus, an important secondary species in reef fish catches of the southeastern United States, was recently the subject of a fishery closure due to the porgy complex quota being exceeded. Knobbed Porgy (n = 448) were aged using sectioned sagittal otoliths. Opaque zones on otolith sections were annular, forming in March–July (peaking in May). Knobbed Porgy ranged from 1 to 21 years, and the largest fish measured 507 mm TL. Body size relationships relating TL, FL, and total body weight (W) for Knobbed Porgy were TL = 1.07·FL + 22.93 (n = 3,173; r2 = 0.97), FL = 0.91·TL − 12.54 (n = 3,173; r2 = 0.97), W = (1.38 × 10−5)TL3.03 (n = 12,732; r2 = 0.92), and W = (7.99 × 10−5)FL2.79 (n = 3,199; r2 = 0.90). Mean length at age was significantly different between Knobbed Porgy collected in North Carolina through southeast Florida (northern region) and those collected in the Florida Keys (southern region). The von Bertalanffy growth equations for Knobbed Porgy were Lt = 412[1 − e−0.20(t + 1.97)] (n = 448) for all regions combined, Lt = 403[1 − e−0.38(t + 0.0001)] (n = 117) for northern region fish, and Lt = 326[1 − e−0.42(t + 1.61)] (n = 331) for southern region fish. Age-varying estimates of natural mortality were 0.36–0.79 year−1 (ages 2–21) for the northern region and 0.42–0.67 year−1 (ages 1–12) for fish from the Florida Keys. Hydrated oocytes were present during February–April in macroscopically staged ovaries (n = 148) for fish from the Florida Keys, and gonadosomatic index data indicated that the month of peak spawning in females was April. The updated life history information should be useful to fishery managers in formulating effective management strategies.
Assessing test–retest reliability of phase contrast MRI for measuring cerebrospinal fluid and cerebral blood flow dynamics
Authors: Sakhare Ashwin R. , Barisano Giuseppe , Pa Judy
Published: April 2019

Purpose

Pathological states occur when cerebrospinal fluid (CSF) and cerebral blood flow (CBF) dynamics become dysregulated in the brain. Phase‐contrast MRI (PC‐MRI) is a noninvasive imaging technique that enables quantitative measurements of CSF and CBF flow. While studies have validated PC‐MRI as an imaging technique for flow, few studies have evaluated its reliability for CSF and CBF flow parameters commonly associated with neurological disease. The purpose of this study was to evaluate test–retest reliability at the cerebral aqueduct (CA) and C2‐C3 area using PC‐MRI to assess the feasibility of investigating CSF and CBF flow dynamics.

Methods

This study was performed on 27 cognitively normal young adults (ages 20‐35 years). Flow data was acquired on a 3T Siemens Prisma using a 2D cine‐PC pulse sequence. Three consecutive flow measurements were acquired at the CA and C2‐C3 area. Intraclass correlation coefficient (ICC) and coefficient of variance (CV) were used to evaluate intrarater, inter‐rater, and test–retest reliability.

Results

Among the 26 flow parameters analyzed, 22 had excellent reliability (ICC > 0.80), including measurements of CSF stroke volume, flush peak, and fill peak, and 4 parameters had good reliability (ICC 0.60‐0.79). 16 flow parameters had a mean CV ≤ 10%, 7 had a CV ≤ 15%, and 3 had a CV ≤ 30%. All CSF and CBF flow measurements had excellent inter‐rater and intrarater reliability (ICC > 0.80).

Conclusion

This study shows that CSF and CBF flow can be reliably measured at the CA and C2‐C3 area using PC‐MRI, making it a promising tool for studying flow dynamics in the central nervous system.
Development of a fast‐scan EPR imaging system for highly accelerated free radical imaging
Authors: Samouilov Alexandre , Ahmad Rizwan , Boslett James , Liu Xiaoping , Petryakov Sergey , Zweier Jay L.
Published: April 2019

Purpose

In continuous wave EPR imaging, the acquisition of high‐quality images was previously limited by the requisite long acquisition times of each image projection that was typically greater than 1 second. To accelerate the process of image acquisition facilitating greater numbers of projections and higher image resolution, instrumentation was developed to greatly accelerate the magnetic field scan that is used to obtain each EPR image projection.

Methods

A low‐inductance solenoidal coil for field scanning was used along with a spherical solenoid air core magnet, and scans were driven by triangular symmetric waves, allowing forward and reverse spectrum acquisition as rapid as 3.8 ms. The uniform distribution of projections was used to optimize the contribution of projections for 3D image reconstruction.

Results

Using this fast‐scan EPR system, high‐quality EPR images of phantoms and perfused rat hearts were performed using trityl or nanoparticulate LiNcBuO (lithium octa‐n‐butoxy‐substituted naphthalocyanine) probes with fast‐scan EPR imaging at L‐band, achieving spatial resolutions of up to 250 micrometers in 1 minute.

Conclusion

Fast‐scan EPR imaging can greatly facilitate the efficient and precise mapping of the spatial distribution of free radical and other paramagnetic probes in living systems.
Quantitative1HNMR spectroscopy for the determination of oxyresveratrol inArtocarpus lacuchaheartwood
Authors: Duangdee Nongnaphat , Chamboonchu Natawadee , Kongkiatpaiboon Sumet , Prateeptongkum Saisuree
Published: April 2019

Introduction

Quantitative nuclear magnetic resonance (qNMR) spectroscopy is an analytical method based on the principles of NMR spectroscopy. The main advantages of this method are its simplicity, time efficiency, high accuracy and reproducibility, and it is a non‐destructive technique.

Objective

To evaluate and standardise the quality ofArtocarpus lacuchaheartwood. A method for quantifying its oxyresveratrol content using qNMR was developed.

Methodology

Proton (1H)NMR (400 MHz) spectroscopy was used to analyse the methanol‐d4solution of a given amount of crude extract ofA. lacuchaheartwood using ethylp‐methoxycinnamate (EPMC) as an internal standard. The qNMR methodology was validated in terms of its linearity and range, limit of quantification (LOQ), stability, precision, and accuracy for the determination of the oxyresveratrol content.

Results

The qNMR method was validated in terms of its linearity, range, LOQ, accuracy, precision, and stability. The quantitative determination of the oxyresveratrol content in the methanolic crude extract ofA. lacuchawas found to be 17% based on1HNMR analysis, which proved to be a reliable method as the results were comparable to those obtained by high‐performance liquid chromatography (HPLC) analysis.

Conclusions

This study validated qNMR spectroscopy as a reliable analytical procedure to determine oxyresveratrol inA. lacuchaheartwood. Therefore, this qNMR method can serve as an alternative to the classical HPLC methods for evaluating and standardising the quality ofA. lacuchaheartwood.
Evaluating the use of bootstrapping in cohort studies conducted with 1:1 propensity score matching—A plasmode simulation study
Authors: Desai Rishi J. , Wyss Richard , Abdia Younathan , Toh Sengwee , Johnson Margaret , Lee Hana , Karami Sara , Major Jacqueline M. , Nguyen Michael , Wang Shirley V. , Franklin Jessica M. , Gagne Joshua J.
Published: April 2019

Purpose

Bootstrapping can account for uncertainty in propensity score (PS) estimation and matching processes in 1:1 PS‐matched cohort studies. While theory suggests that the classical bootstrap can fail to produce proper coverage, practical impact of this theoretical limitation in settings typical to pharmacoepidemiology is not well studied.

Methods

In a plasmode‐based simulation study, we compared performance of the standard parametric approach, which ignores uncertainty in PS estimation and matching, with two bootstrapping methods. The first method only accounted for uncertainty introduced during the matching process (the observation resampling approach). The second method accounted for uncertainty introduced during both PS estimation and matching processes (the PS reestimation approach). Variance was estimated based on percentile and empirical standard errors, and treatment effect estimation was based on median and mean of the estimated treatment effects across 1000 bootstrap resamples. Two treatment prevalence scenarios (5% and 29%) across two treatment effect scenarios (hazard ratio of 1.0 and 2.0) were evaluated in 500 simulated cohorts of 10 000 patients each.

Results

We observed that 95% confidence intervals from the bootstrapping approaches but not the standard approach, resulted in inaccurate coverage rates (98%‐100% for the observation resampling approach, 99%‐100% for the PS reestimation approach, and 95%‐96% for standard approach). Treatment effect estimation based on bootstrapping approaches resulted in lower bias than the standard approach (less than 1.4% vs 4.1%) at 5% treatment prevalence; however, the performance was equivalent at 29% treatment prevalence.

Conclusion

Use of bootstrapping led to variance overestimation and inconsistent coverage, while coverage remained more consistent with parametric estimation.
Exposure to a Motor Vehicle Collision and the Risk of Future Neck Pain: A Systematic Review and Meta‐Analysis
Authors: Nolet Paul S. , Emary Peter C. , Kristman Vicki L. , Murnaghan Kent , Zeegers Maurice P. , Freeman Michael D.
Published: April 2019

Objective

To summarize the literature that has examined the association between a motor vehicle collision (MVC) related neck injury and future neck pain (NP) in comparison with the population that has not been exposed to neck injury from an MVC.

Literature Survey

Neck injury resulting from an MVC is associated with a high rate of chronicity. Prognosis studies indicate 50% of injured people continue to experience NP a year after the collision. This is difficult to interpret due to the high prevalence of NP in the general population.

Methodology

We performed a systematic review of the literature using five electronic databases, searching for risk studies on exposure to an MVC and future NP published from 1998 to 2018. The outcome of interest was future NP. Eligible risk studies were critically appraised using the modified Quality in Prognosis Studies (QUIPS) instrument. The results were summarized using best‐evidence synthesis principles, a random effects meta‐analysis, metaregression, and testing for publication bias was performed with the pooled data.

Synthesis

Eight articles were identified of which seven were of lower risk of bias. Six studies reported a positive association between a neck injury in an MVC and future NP compared to those without a neck injury in an MVC. Pooled analysis of the six studies indicated an unadjusted relative risk of future NP in the MVC exposed population with neck injury of 2.3 (95% CI [1.8, 3.1]), which equates to a 57% attributable risk under the exposed. In two studies where exposed participants were either not injured or injury status was unknown, there was no increased risk of future NP.

Conclusions

There was a consistent positive association among studies that have examined the association between MVC‐related neck injury and future NP. These findings are of potential interest to clinicians, insurers, patients, governmental agencies, and the courts.

Level of Evidence

I.
A surface temperature and moisture intercomparison study of the Weather Research and Forecasting model, in‐situ measurements and satellite observations over the Atacama Desert
Authors: Fonseca Ricardo , Zorzano‐Mier María‐Paz , Azua‐Bustos Armando , González‐Silva Carlos , Martín‐Torres Javier
Published: April 2019

Good knowledge of the environmental conditions of deserts on Earth is relevant for climate studies. The Atacama Desert is of particular interest as it is considered to be the driest region on Earth. We have performed simulations using the Weather Research and Forecasting (WRF) model over the Atacama Desert for two week‐long periods in the austral winter season coincident with surface temperature and relative humidity in‐situ observations at three sites. We found that the WRF model generally overestimates the daytime surface temperature, with biases of up to 11°C, despite giving a good simulation of the relative humidity. In order to improve the agreement with observed measurements, we conducted sensitivity experiments in which the surface albedo, soil moisture content and five tuneable parameters in the Noah Land Surface Model (namely soil porosity, soil suction, saturated soil hydraulic conductivity, the b parameter used in hydraulic functions and the quartz fraction) are perturbed. We concluded that an accurate simulation is not possible, most likely because the Noah Land Surface Model does not have a groundwater table that may be shallow in desert regions. The WRF‐predicted land surface temperature is also evaluated against that estimated from the Moderate Resolution Imaging Spectroradiometer (MODIS) instrument. While at night the satellite‐derived and ground‐based measurements are generally in agreement, during the day MODIS estimates are typically lower by as much as 17°C. This is attributed to the large uncertainty in the MODIS‐estimated land surface temperatures in arid and semi‐arid regions. The findings of this work highlight the need for ground‐based observational networks in remote regions such as the Atacama Desert where satellite‐derived and model products may not be very accurate.
A continuous‐time Markov chain model for redundancy allocation problem: An economic analysis
Authors: Tohidi Hossein , Chavoshi Saeed , Bahmaninezhad Azadeh
Published: April 2019

Reliability of an engineering system can be improved by investing on redundant (spare) parts. However, the cost‐efficiency of such an investment is a significant concern that needs to be taken into consideration in practice. To do so, a continuous‐time Markov chain (CTMC) model is presented in this paper to analyze the system's reliability by allocating redundant components. The developed model can also capture the system's repair and failure conditions by defining appropriate states in CTMC. Subsequently, the net present value (NPV) approach is utilized for a variety of scenarios to investigate the effectiveness of investment on spare parts using the break‐even point (BEP) analysis. Afterwards, a comprehensive analysis is carried out to examine the impact of input parameters including interest rate, initial cost of investment, and periodic profit on the decision making process to find the optimal number of spare parts.
Concise Review: Precision Matchmaking: Induced Pluripotent Stem Cells Meet Cardio-Oncology
Authors: Nair Pooja , Prado Maricela , Perea-Gil Isaac , Karakikes Ioannis
Published: April 2019

As common chemotherapeutic agents are associated with an increased risk of acute and chronic cardiovascular complications, a new clinical discipline, cardio-oncology, has recently emerged. At the same time, the development of preclinical human stem cell-derived cardiovascular models holds promise as a more faithful platform to predict the cardiovascular toxicity of common cancer therapies and advance our understanding of the underlying mechanisms contributing to the cardiotoxicity. In this article, we review the recent advances in preclinical cancer-related cardiotoxicity testing, focusing on new technologies, such as human induced pluripotent stem cell-derived cardiomyocytes and tissue engineering. We further discuss some of the limitations of these technologies and present future directions. Stem Cells Translational Medicine  2019;8:758–767
Integrating multiple‐domain rules for disease classification
Authors: Mauro Christine , Shear M. Katherine , Wang Yuanjia
Published: April 2019

In psychiatry, clinicians use criteria sets from the Diagnostic and Statistical Manual of Mental Disorders to diagnose mental disorders. Most criteria sets have several symptom domains, and in order to be diagnosed, an individual must meet the minimum number of symptoms required by each domain. Some efforts are now focused on adding biomarkers to these symptom domains to facilitate the detection of and highlight the neurobiological basis of psychiatric disorders. Thus, a new criteria set may consist of both clinical symptom counts in several domains and continuous biomarkers. In this paper, we propose a method to integrate classification rules from multiple data sources to estimate an optimal criteria set. Each domain‐specific rule can be counts of symptoms, a linear function of symptoms, or even nonparametric. The overall classification rule is the intersection of these domain‐specific rules. Based on examining the expected population loss function, we propose two iterative algorithms using either support vector machines or logistic regression to fit intersection rules consistent with the Diagnostic and Statistical Manual of Mental Disorders. In simulation studies, these proposed methods are comparable with the true decision rule. The methods are applied to the motivating study to construct a criteria set for complicated grief. The developed criteria set shows a substantial improvement in sensitivity and specificity compared to the current standards on an independent validation study.
Synergetic Coupling of Lithiophilic Sites and Conductive Scaffolds for Dendrite‐Free Lithium Metal Anodes
Authors: Chen Xiao‐Ru , Li Bo‐Quan , Zhao Chang‐Xin , Zhang Rui , Zhang Qiang
Published: April 2019

Lithium metal is highly considered as an ideal anode material because of its ultrahigh theoretical capacity of 3680 mA h g−1 and the lowest potential of −3.04 V versus the standard hydrogen electrode. However, uncontrollable lithium dendrite growth severely impedes the practical applications of lithium metal batteries. The introduction of a lithium host is an effective strategy to inhibit lithium dendrite growth, where lithiophilicity and conductivity of the lithium host play the dominant role. In this contribution, the synergistic effect of lithiophilic sites and conductive scaffolds is investigated to construct an optimized lithium host for dendrite‐free lithium metal anodes. Consequently, the lithium host with balanced lithiophilicity and conductivity demonstrates excellent electrochemical performances regarding to high Coulombic efficiency of 98% stable for 300 cycles at 1.0 mA cm−2 and improved capacity retention of 86.2% after 100 cycles in LiFePO4 full cells. The synergistic coupling of lithiophilicity and conductivity of lithium hosts enhances the understanding of lithiophilic chemistry to achieve next‐generation high‐performance batteries.
The social, the ecological, and the adaptive. Von Bertalanffy's general systems theory and the adaptive governance of social‐ecological systems
Authors: Van Assche Kristof , Verschraegen Gert , Valentinov Vladislav , Gruezmacher Monica
Published: April 2019

Based on biological insights, Ludwig von Bertalanffy coined general systems theory (GST) and later expanded his perspective, exploring what GST could mean for other disciplines and other types of systems. We make a case for the relevance, or rather, the importance, of GST for coming to a new understanding of the resilience of social‐ecological systems and the possible forms of adaptive governance that might increase such resilience. After analyzing the conceptual structure of the resilience paradigm and of GST, we identify concepts in resilience thinking where GST provides new confirmation or modifies the perspective: complexity, evolution, self‐organization, and adaptation. We discuss post‐Bertalanffy developments in the interdisciplinary and twinned fields of systems theory and complexity studies that can provide bridging concepts between GST and resilience thinking. In conclusion, we emphasize the need for both cognitive and institutional resilience to foster adaptive governance. We highlight the management of couplings between systems and the switching between forms of understanding and forms of organization, where self‐organization and more centralized forms of steering can alternate and combine.
Concise Review: Genetic and Epigenetic Regulation of Cardiac Differentiation from Human Pluripotent Stem Cells
Authors: Fujita Jun , Tohyama Shugo , Kishino Yoshikazu , Okada Marina , Morita Yuika
Published: April 2019

Human pluripotent stem cells (hPSCs), including both embryonic stem cells and induced pluripotent stem cells, are the ideal cell sources for disease modeling, drug discovery, and regenerative medicine. In particular, regenerative therapy with hPSC-derived cardiomyocytes (CMs) is an unmet medical need for the treatment of severe heart failure. Cardiac differentiation protocols from hPSCs are made on the basis of cardiac development in vivo. However, current protocols have yet to yield 100% pure CMs, and their maturity is low. Cardiac development is regulated by the cardiac gene network, including transcription factors (TFs). According to our current understanding of cardiac development, cardiac TFs are sequentially expressed during cardiac commitment in hPSCs. Expression levels of each gene are strictly regulated by epigenetic modifications. DNA methylation, histone modification, and noncoding RNAs significantly influence cardiac differentiation. These complex circuits of genetic and epigenetic factors dynamically affect protein expression and metabolic changes in cardiac differentiation and maturation. Here, we review cardiac differentiation protocols and their molecular machinery, closing with a discussion of the future challenges for producing hPSC-derived CMs. Stem Cells  2019;37:992–1002
Quantitative analysis of the yeast pheromone pathway
Authors: Shellhammer James P. , Pomeroy Amy E. , Li Yang , Dujmusic Lorena , Elston Timothy C. , Hao Nan , Dohlman Henrik G.
Published: April 2019

The pheromone response pathway of the yeastSaccharomyces cerevisiaeis a well‐established model for the study of G proteins and mitogen‐activated protein kinase (MAPK) cascades. Our longstanding ability to combine sophisticated genetic approaches with established functional assays has provided a thorough understanding of signalling mechanisms and regulation. In this report, we compare new and established methods used to quantify pheromone‐dependent MAPK phosphorylation, transcriptional induction, mating morphogenesis, and gradient tracking. These include both single‐cell and population‐based assays of activity. We describe several technical advances, provide example data for benchmark mutants, highlight important differences between newer and established methodologies, and compare the advantages and disadvantages of each as applied to the yeast model. Quantitative measurements of pathway activity have been used to develop mathematical models and reveal new regulatory mechanisms in yeast. It is our expectation that experimental and computational approaches developed in yeast may eventually be adapted to human systems biology and pharmacology.
Resource Abundance, Fisheries Management, and Fishing Ports: The U.S. Atlantic Sea Scallop Fishery
Authors: Lee Min-Yang , Benjamin Sharon , Carr-Harris Andrew , Hart Deborah , Speir Cameron
Published: April 2019

The Atlantic Sea Scallop fishery has grown tremendously over the past twenty years. The location and magnitude of harvestable biomass fluctuates dramatically due to both natural variation and the explicitly spatial management system designed to allow small individuals to grow larger and more valuable. These fluctuations in natural advantages can have profound effects on fishing ports. We use methods from economic growth literature to show that ports with lower initial scallop landings have grown the fastest. Furthermore, good access to biomass influences long-run changes in landings, although this effect exhibits considerable variability across ports. We also find evidence of returns to scope, suggesting that ports with other fishing activities could be well positioned to attract new scalloping activity when stock conditions are favorable. Further investigation of the largest ports using time-series methods also shows a high degree of variability; there are long-run relationships between scallop fishing and harvestable scallop stock in some ports, short-run relationships in some ports, and no relationship between the two in others. We interpret this as evidence that heterogeneity in the natural productivity of the ocean combined with explicitly spatial fisheries management has induced a spatial component to the port-level response to changes in biomass availability.
Populist leaders and political parties
Authors: Barber N. W.
Published: April 2019

Populism is a particular type of constitutional pathology; a brand of groupthink in which a leader establishes a direct connection with the people and, by virtue of this connection, is able to govern outside the established constitutional processes of the state. This Article reflects on the interaction between populism and political parties. It argues that one of the roles of political parties is to act as a medium between political elites and the people; a medium that can, or should, enable the people to exercise control over this elite through their membership of parties. Populism therefore presents a threat to the proper operation of political parties, and the proper operation of political parties correspondingly threatens populism.

This Article begins by reflecting on the nature of populism. It does not pretend to provide a complete account of that phenomenon, but rather aspires to identify one strand of populist rule: A particular type of connection between the leader and her people. Second, the paper reflects on the constitutional role of political parties. Whilst political parties have often been treated critically in British constitutional scholarship, it will be argued that they are essential to the success of the democratic process: Modern representative democracy cannot function in their absence. Finally, these two sections of the paper will be drawn together: One explanation for the rise of populism is the weakness of political parties, and one way of combating, or mitigating, populism is for the state, and the citizenry, to support and facilitate parties. This Article suggests a correlation between the decline of political parties and the rise of populism, but it cautiously avoids making claims of causation. It could be that the decline of political parties leads to the rise of populism, as voters who are faced with a choice of superannuated parties turn, instead, to charismatic individuals. Or it could be that the rise of populism leads to the decline of political parties, as voters develop a direct relationship with leaders and, as a result, cease to engage with each other within the context of parties. Or, perhaps, these interactions might occur together, forming a feedback loop, with the decline of parties leading to the rise of populism which, in turn, hastens party decay.
Resolution 1106 (2168/18) (OAS), Precautionary Measure No. 731–18, & Precautionary Measure No. 505-18 (IACHR)
Authors: Hernández-Truyol Berta Esperanza
Published: April 2019

In the spring of 2018, the White House and executive agencies issued a series of orders aimed at more aggressive enforcement against irregular entry of migrants at the southwest border. In analyzing the legal validity of the new U.S. immigration policy decisions, the Inter-American System questioned and strongly condemned the U.S. policy and practice of separating migrant families. On June 29, 2018, the Permanent Council of the Organization of American States (OAS) issued a resolution that rejected any migration policy that resulted in the separation of families. Specifically, it urged the U.S. government to implement measures to avoid the separation of families, to seek unification of children and parents already separated, and to promote the identification of migrants and refugee seekers in accordance with international law. After the issuance of the resolution, the Inter-American Commission on Human Rights (IACHR) granted Precautionary Measure No. 731–18, Regarding Migrant Children Affected by the “Zero Tolerance” Policy Regarding the United States of America (the children's measure), and Precautionary Measure No. 505–18, Concerning Vilma Aracely López Juc de Coc and Others Regarding the United States of America (the parents’ measure), both of which recognized that the rights to family life and personal integrity were at risk.
Stable and unstable miscible displacements in layered porous media
Authors: Nijjer Japinder S. , Hewitt Duncan R. , Neufeld Jerome A.
Published: April 2019

The effect of permeability heterogeneities and viscosity variations on miscible displacement processes in porous media is examined using high-resolution numerical simulations and reduced theoretical modelling. The planar injection of one fluid into a fluid-saturated, two-dimensional porous medium with a permeability that varies perpendicular to the flow direction is studied. Three cases are considered, in which the injected fluid is equally viscous, more viscous or less viscous than the ambient fluid. In general it is found that the flow in each case evolves through three regimes. At early times, the flow exhibits the concentration evolves diffusively, independent of both the permeability structure and the viscosity ratio. At intermediate times, the flow exhibits different dynamics including channelling and fingering, depending on whether the injected fluid is more or less viscous than the ambient fluid, and depending on the relative magnitude of the viscosity and permeability variations. Finally, at late times, the flow becomes independent of the viscosity ratio and dominated by shear-enhanced (Taylor) dispersion. For each of the regimes identified above, we develop reduced-order models for the evolution of the transversely averaged concentration and compare them to the full numerical simulations.
Impact of misinformation in temporal network epidemiology
Authors: Holme Petter , Rocha Luis E. C.
Published: April 2019

We investigate the impact of misinformation about the contact structure on the ability to predict disease outbreaks. We base our study on 31 empirical temporal networks and tune the frequencies in errors in the node identities or time stamps of contacts. We find that for both these spreading scenarios, the maximal misprediction of both the outbreak size and time to extinction follows an stretched exponential convergence as a function of the error frequency. We furthermore determine the temporal-network structural factors influencing the parameters of this convergence.
Beyond homophily: Incorporating actor variables in statistical network models
Authors: Snijders Tom A.B. , Lomi Alessandro
Published: April 2019

We consider the specification of effects of numerical actor attributes, having an interval level of measurement, in statistical models for directed social networks. A fundamental mechanism is homophily or assortativity, where actors have a higher likelihood to be tied with others having similar values of the variable under study. But there are other mechanisms that may also play a role in how the attribute values of two actors influence the likelihood of a tie between them. We discuss three additional mechanisms: aspiration, the tendency to send more ties to others having high values; attachment conformity, sending more ties to others whose values are close to the “social norm”; and sociability, where those having higher values will tend to send more ties generally. These mechanisms may operate jointly, and then their effects will be confounded. We present a specification representing these effects simultaneously by a four-parameter quadratic function of the values of sender and receiver. Flexibility can be increased by a five-parameter extension. We argue that for numerical actor attributes having important effects on directed networks, these specifications may provide an improvement. An illustration is given of dependence of advice ties on academic grades, analyzed by the Stochastic Actor-oriented Model.
Reparative Justice for Climate Refugees
Authors: Buxton Rebecca
Published: April 2019

This paper sketches an account of reparative justice for climate refugees, focusing on total land loss due to sea-level rise. I begin by outlining the harm of this loss in terms of self-determination and cultural heritage. I then consider, first, who is owed these reparations? Second, who should pay such reparations? Third, in what form should the reparations be paid? I end with thoughts on the project of reparative justice more generally, arguing that such obligations do not depend upon a perfect account of how reparations might be fulfilled; we simply have an obligation to shoot the arrow as close to the target as we can.
The three waves of Arctic urbanisation. Drivers, evolutions, prospects
Authors: Laruelle Marlene
Published: April 2019

The 2014 Arctic Human Development Report identified “Arctic settlements, cities, and communities” as one of the main gaps in knowledge of the region. This article looks at circumpolar urbanisation trends. It dissociates three historical waves of Arctic urbanisation: from the sixteenth century to the early twentieth century (the “colonial” wave), from the 1920s to the 1980s in the specific case of the Soviet urbanisation of the Arctic (the “Soviet” wave), and from the 1960s−70s to the present as a circumpolar trend (the “globalized” wave). It then discusses the three drivers of the latest urbanisation wave (resources, militarisation, and public services) and the prospects for Arctic cities’ sustainability in the near future.
Informal care provision across multiple generations in China
Authors: Falkingham Jane , Evandrou Maria , Qin Min , Vlachantoni Athina
Published: April 2019

With increasing life expectancy, changes in family structure and, most recently, the relaxation of the hitherto strict family planning policies, understanding how mid-life individuals support multiple generations, particularly their older parents and younger grandchildren, is of increasing research and policy significance in China. This paper analyses data from the 2011 China Health and Retirement Longitudinal Study (CHARLS) to examine the characteristics of Chinese mid-life individuals aged 45–64 who are potentially being ‘sandwiched’ between providing care to older parents/parents-in-law and/or younger grandchildren (under age 16). Binary logistic and multinomial regression models shed light on the factors associated with providing support to one generation or multiple generations. The results highlight that amongst the Chinese mid-life sandwich generation, 58 per cent only provide care to their young grandchildren, 23 per cent only provide care to their parents/parents-in-law, whilst 15 per cent are simultaneously supporting both generations. Rather than acting as competing demands upon the mid-lifers’ time, the multivariate analysis provides evidence that the provision of intergenerational care is complementary, with caring for grandchildren increasing the probability of also supporting one's parents/parents-in-law, andvice versa. However, an increase in the number of younger grandchildren has a negative impact on the care provided to older parents/parents-in-law, indicating that at higher care intensities there may be competing demands across the generations.
Chinese preschoolers’ acquisition of temporal adverbs indicating past, present, and future: a corpus-based study
Authors: LIANG Lu Yao , WU Dandan , LI Hui
Published: April 2019

This study investigated the development of temporal adverbs in early childhood Mandarin. All cases of temporal adverbs indicating the past, present, and future were extracted from the Early Child Mandarin Corpus (168 children in four age groups: 2;6, 3;6, 4;6, 5;6). Data analyses indicated: (1) Mandarin-speaking children produced a repertoire of 21 types of temporal adverbs, and the children in the first age group (M = 2;6) were capable of using temporal adverbs to denote past, present, and future events; (2) within each age group, the children produced significantly more future temporal adverbs than the other two subtypes; and (3) there was a significant age effect that, with increased age, more children were able to produce all subtypes of temporal adverbs. Overall, findings of this corpus-based investigation shed light upon Chinese children's early-attained ability to express the three fundamental notions of time by resorting to the appropriate linguistic devices.
Le paragraphe mobile
Authors: Slauter Will
Published: April 2019

Dans le monde atlantique du XVIIIesiècle, les gazettes et journaux politiques se copient, se traduisent, et se répondent. La technologie qui facilite le mouvement des informations à cette époque, c’est le paragraphe. Cette technologie de lecture ancienne devient au XVIIIesiècle l’unité de base des nouvelles imprimées, à la fois véhicule des messages politiques et instrument d’analyse de ces messages. Grâce aux interventions des rédacteurs, imprimeurs, lecteurs et capitaines de bateaux, les nouvelles changent de forme et de fond tandis qu’elles voyagent. Cet article, qui repose sur des études de journalisme en Europe, Grande-Bretagne et Amérique du Nord, met à profit une lecture comparative des périodiques de langues anglaise, française et espagnole pour décrypter les processus de création, de transmission et de réception des nouvelles. Il montre, à partir d’exemples précis tirés de la guerre d’indépendance américaine, l’oeuvre collective qu’est le journalisme transatlantique au XVIIIesiècle. Ce faisant, il met en valeur le paragraphe comme objet d’étude historique.
Assessing the Spatial Accuracy of the Reconstruction in Atom Probe Tomography and a New Calibratable Adaptive Reconstruction
Authors: Ceguerra Anna V. , Day Alec C. , Ringer Simon P.
Published: April 2019

We define a measure for the accuracy of tomographic reconstruction in atom probe tomography, named here the spatial error index. We demonstrate that this index can be used to compare rigorously the spatial accuracy of various different approaches to the calculation of tomographic reconstruction. This is useful, for example, to evaluate the performance of alternate tomographic reconstruction approaches, and ensures that the comparisons are independent of individual data quality or other instrumental parameters. We then introduce a new “adaptive reconstruction” formalism that uses a progression of reconstruction parameters based on a per-atom correction from the cube root of the inverse of the voltage, along with linear correction factors linked to the evaporation sequence. We apply the measure for spatial accuracy to this new reconstruction protocol.