bluuebunny/crossref_metadata_2025 huggingface dataset:
Characterizing the invasion of different breast cancer cell lines with distinct E-cadherin status in 3D using a microfluidic system
Authors: Eslami Amirabadi H. , Tuerlings M. , Hollestelle A. , SahebAli S. , Luttge R. , van Donkelaar C. C. , Martens J. W. M. , den Toonder J. M. J.
Published: November 2019

E-cadherin is a cell-cell adhesion protein that plays a prominent role in cancer invasion. Inactivation of E-cadherin in breast cancer can arise from gene promoter hypermethylation or genetic mutation. Depending on their E-cadherin status, breast cancer cells adopt different morphologies with distinct invasion modes. The tumor microenvironment (TME) can also affect the cell morphology and invasion mode. In this paper, we used a previously developed microfluidic system to quantify the three-dimensional invasion of breast cancer cells with different E-cadherin status, namely MCF-7, CAMA-1 and MDA-MB-231 with wild type, mutated and promoter hypermethylated E-cadherin, respectively. The cells migrated into a stable and reproducible microfibrous polycaprolactone mesh in the chip under a programmed stable chemotactic gradient. We observed that the MDA-MB-231 cells invaded the most, as single cells. MCF-7 cells collectively invaded into the matrix more than CAMA-1 cells, maintaining their E-cadherin expression. The CAMA-1 cells exhibited multicellular multifocal infiltration into the matrix. These results are consistent with what is seen in vivo in the cancer biology literature. In addition, comparison between complete serum and serum gradient conditions showed that the MDA-MB-231 cells invaded more under the serum gradient after one day, however this behavior was inverted after 3 days. The results showcase that the microfluidic system can be used to quantitatively assess the invasion behavior of cancer cells with different E-cadherin expression, for a longer period than conventional invasion models. In the future, it can be used to quantitatively investigate effects of matrix structure and cell treatments on cancer invasion.
Open Textbooks: A Balance Between Empowerment and Disruption
Authors: Algers Anne
Published: November 2019

The use of open textbooks in universities is according to some organisations changing the higher education landscape and is promising for the mainstream adoption of OER. The aim of this paper is to analyse authors’ views of agency and empowerment when they plan, create and reflect on their open textbooks, their teaching and students’ learning. Another aim is to analyse the ways in which knowledge supports authors’ creation of open textbooks and tensions inherent in this practice. This qualitative study used a modified version of a validated questionnaire for 1 h long semi-structured interviews with four interviewees, conducted over 4 days. The data from the interviews were analysed in three steps combining two coding structures, for self-regulated learning and levels of contradictions. The results suggest that the four authors engendered a sense of relational agency in the creation process. They indicated that they valued openness and the pedagogical project itself by highlighting both teachers’ and learners’ perception of agency and empowerment. The data also support the authors’ concerns about the disruptive nature of open textbooks regarding stability versus adaptation and data ownership as it relates to use of learning analytics and commercial interests, indicating considerable contradictions in open textbook practices.
Counseling young women with early breast cancer on fertility preservation
Authors: ter Welle-Butalid M. E. (Elena) , Vriens I. J. H. (Ingeborg) , Derhaag J. G. (Josien) , Leter E. M. (Edward) , de Die-Smulders C. E. (Christine) , Smidt M. (Marjolein) , van Golde R. J. T. (Ron) , Tjan-Heijnen V. C. G. (Vivianne)
Published: November 2019

Purpose

Women with early-stage breast cancer may still have a future child wish, while chemotherapy may impair fertility. To pursue on fertility preservation shortly after breast cancer diagnosis is complex. This review holds a critical reflection on all topics that need to be counseled to give them the opportunity to make a well-informed decision before starting any oncological treatment.

Methods

A comprehensive literature review was performed on papers published in English language on breast cancer in young women, risk of chemotherapy-induced infertility, fertility preservation techniques, impact of possible mutation carriership, and future pregnancy outcome.

Results

Below 40 years of age, the risk of permanent chemotherapy-induced ovarian function failure is approximately 20%, where taxanes do not significantly add to this risk. Overall, 23% of reported women who performed fertility preservation by cryopreserving oocytes or embryos returned for embryo transfer. Of these, 40% gave live birth. Both fertility preservation in women diagnosed with breast cancer and pregnancy after treatment seem safe with respect to breast cancer survival. Women who have a genetic predisposition for breast cancer like BRCA gene mutation should also be informed about the possibility of pre-implantation genetic diagnosis.

Conclusions

Women with an early stage of breast cancer and a possible future child wish should be referred to an expertise center in breast cancer, fertility preservation, and genetics in this complex decision-making process, shortly after diagnosis.
Rare Loot Box Rewards Trigger Larger Arousal and Reward Responses, and Greater Urge to Open More Loot Boxes
Authors: Larche Chanel J. , Chini Katrina , Lee Christopher , Dixon Mike J. , Fernandes Myra
Published: November 2019

Loot boxes are a purchasable video-game feature consisting of randomly determined, in-game virtual items. Due to their chance-based nature, there is much debate as to whether they constitute a form of gambling. We sought to address this issue by examining whether players treat virtual loot box rewards in a way that parallels established reward reactivity for monetary rewards in slots play. Across two sets of experiments, we show that loot boxes containing rarer items are more valuable, arousing, rewarding and urge-inducing to players, similar to the way slots gamblers treat rare large wins in slots play. Importantly, we show in Experiment 2 that the duration of Post Reinforcement Pauses, an index of reward reactivity, are longer for boxes with rarer items. Boxes containing rarer rewards also trigger larger Skin Conductance Responses and larger force responses—indices of positive arousal. Findings of Experiment 2 also revealed that there was an increase in anticipatory arousal prior to the reveal of loot box rewards. Collectively, our results elucidate the structural similarities between loot boxes and specific gambling games. The fact that players find rarer game items hedonically rewarding and motivating has implications for potential risky or excessive loot box use for some players.
On the variational principle for the non-linear Schrödinger equation
Authors: Mihálka Zsuzsanna É. , Margócsy Ádám , Szabados Ágnes , Surján Péter R.
Published: November 2019

While variation of the energy functional yields the Schrödinger equation in the usual, linear case, no such statement can be formulated in the general nonlinear situation when the Hamiltonian depends on its eigenvector. In this latter case, as we illustrate by sample numerical calculations, the points of the energy expectation value hypersurface where the eigenvalue equation is satisfied separate from those where the energy is stationary. We show that the variation of the energy at the eigensolution is determined by a generalized Hellmann–Feynman theorem. Functionals, other than the energy, can, however be constructed, that result the nonlinear Schrödinger equation upon setting their variation zero. The second centralized moment of the Hamiltonian is one example.
Inductive Heating Assisted-Catalytic Dehydrogenation of Tetralin as a Hydrogen Source for Downhole Catalytic Upgrading of Heavy Oil
Authors: Hart Abarasi , Adam Mohamed , Robinson John P. , Rigby Sean P. , Wood Joseph
Published: November 2019

The Toe-to-Heel Air Injection (THAI) combined with a catalytic add-on (CAPRI, CATalytic upgrading PRocess In-situ) have been a subject of investigation since 2002. The major challenges have been catalyst deactivation due to coke deposition and low temperatures (~ 300 °C) of the mobilised hot oil flowing over the catalyst packing around the horizontal well. Tetralin has been used to suppress coke formation and also improve upgraded oil quality due to its hydrogen-donor capability. Herein, inductive heating (IH) incorporated to the horizontal production well is investigated as one means to resolve the temperature shortfall. The effect of reaction temperature on tetralin dehydrogenation and hydrogen evolution over NiMo/Al2O3 catalyst at 250–350 °C, catalyst-to-steel ball ratio (70% v/v), 18 bar and 0.75 h−1 was investigated. As temperature increased from 250 to 350 °C, tetralin conversion increased from 40 to 88% while liberated hydrogen increased from 0.36 to 0.88 mol based on 0.61 mol of tetralin used. The evolved hydrogen in situ hydrogenated unreacted tetralin to trans and cis-decalins with the selectivity of cis-decalin slightly more at 250 °C while at 300–350 °C trans-decalin showed superior selectivity. With IH the catalyst bed temperature was closer to the desired temperature (300 °C) with a mean of 299.2 °C while conventional heating is 294.3 °C. This thermal advantage and the nonthermal effect from electromagnetic field under IH improved catalytic activity and reaction rate, though coke formation increased.
Hydraulic Conductivity of Compacted Lime-Softening Sludge Used as Landfill Liners
Authors: Dąbska Agnieszka
Published: November 2019

The research goal was to investigate the hydraulic conductivity of compacted lime-softening sludge as a material to be applied to landfill liners. In doing so, the effect of compaction and moulding moisture content on the sludge hydraulic conductivity was assessed. An approximate polynomial k10meanat hydraulic gradients ≥30 for degree of compaction (0.95–1.05) and moulding moisture content (28%–36%) was determined. The results of short-term tap water permeation tests revealed that all hydraulic conductivity values were less than 2.5•10–8 m/s. A lowest hydraulic conductivity of 6.5•10–9 m/s, as well as a corresponding moisture content of 31% were then established. The long-term hydraulic conductivity was measured with tap water, distilled water, NaOH and HCl solutions and municipal waste leachate. The factors of permeating liquids and permeation time significantly affected the initial hydraulic conductivity. The long-term hydraulic conductivity increased for NaOH and HCl solutions and decreased for tap and distilled water. A significant reduction of hydraulic conductivity was observed for leachate permeation. The investigated material met the requirements for the liner systems of inert landfill sites regardless of pH and the limit value for hazardous and non-hazardous waste landfills.
Enhanced interlayer trapping of Pb(II) ions within kaolinite layers: intercalation, characterization, and sorption studies
Authors: Maged Ali , Ismael Ismael Sayed , Kharbish Sherif , Sarkar Binoy , Peräniemi Sirpa , Bhatnagar Amit
Published: November 2019

Lead (Pb(II)) pollution in water poses a serious threat to human health in many parts of the world. In the past decades, research has been aimed at developing efficient and cost-effective methods to address the problem. In this study, dimethyl sulfoxide (DMSO) and potassium acetate (K-Ac) intercalated kaolinite complexes were synthesized and subsequently utilized for Pb(II) removal from water. The intercalation of kaolinite with DMSO was found to be useful for expanding the interlayer space of the clay mineral from 0.72 to 1.12 nm. Kaolinite intercalation with K-Ac (KDK) increased the interlayer space from 1.12 to 1.43 nm. The surface area of KDK was found to be more than threefold higher as compared to natural kaolinite (NK). Batch experimental results revealed that the maximum Pb(II) uptake capacity of KDK was 46.45 mg g−1which was higher than the capacity of NK (15.52 mg g−1). Reusability studies showed that KDK could be reused for 5 cycles without substantially losing its adsorption capacity. Furthermore, fixed-bed column tests confirmed the suitability of KDK in continuous mode for Pb(II) removal. Successful application of intercalated kaolinite for Pb(II) adsorption in batch and column modes suggests its application in water treatment (especially removal of divalent metals).
Study of Energy Harvesting from Low-Frequency Vibration with Ferromagnetic Powder and Non-magnetic Fluid
Authors: Shirai Haruhiko , Mitamura Hiromichi , Arai Nobuaki , Moriya Kazuyuki
Published: November 2019

The movement of the creature and the almost wave in the ocean is a low vibration of random energy with a frequency range of 0.1–10 Hz. Because of its low frequency, the opinion has been that electrical energy generation from this low-frequency wave motion through the electromagnetic induction method is difficult. In this study, an electrical generator was created by the electromagnetic induction method by putting a small mass of ferromagnetic powder in nonmagnetic fluid. A broadband vibration energy harvesting model was created in which vibrations are broadened through a multi-degree of freedom oscillation system using ferromagnetic powder. To generate electricity from low-frequency vibrations (1 Hz or less), a non-resonant type model was created by adding fluid to the ferromagnetic powder model and the simulation results confirmed using computational fluid dynamics by creating a working energy harvesting device.
A Different Conversation: Psychological Research and the Problem of Self in Autism
Authors: Fasulo Alessandra
Published: November 2019

Observations about peculiarities in the autistic population concerning type and frequency of references to subjective states, and lack of perspective taking, have been on the whole referred to as the paradox of the autistic self, i.e. a co-presence of ego-centeredness and weak self-referentiality (Lombardo & Baron Cohen 2010). Prevalent approaches in autism ascribe these peculiarities to high order disfunctions caused by neurological factors, such as defective self-encoding processes. Two narratives told by an adult man with Asperger during counselling are examined with Conversation Analysis; the analysis identifies features that may lead to descriptions like the paradox of autistic self, but also reveals competences related to perspective-taking and narrative construction. Drawing on Bruner’s narrative theory, as well on recent interactional research on autism and the psychology of self, it is suggested that a relatively limited practice with narrative co-construction might be at the origin of the peculiarities observed. A socio-developmental approach to the understanding of autism not only can provide explanations compatible with first and second person accounts of life with autism, but can also open new paths for researching ways of self-construction that are less reliant on social interaction. The article finally challenges assumptions in psychological research about the ability of humans to access their internal states, and discusses how such assumptions can deter understanding of atypical populations.
Impacts of culture-wise shrimp farming activities on hydrogeochemistry: a case study from Chidambaram taluk, Cuddalore district, Tamil Nadu, India
Authors: Rajendran Gangadharan , Peter Nila Rekha
Published: November 2019

Shrimp farming is one of the most important aquaculture practices in terms of area, production, employment and foreign exchange generation in India. In recent years, the growth and intensification of shrimp farms in the study area have been explosive, and setting up of new shrimp farms along the coastal areas has also become a matter of apprehension among the environmentalists. An extensive survey made by environmentalists elsewhere shows mixed opinion, but ascertains the real scenario as facts. A total of about 46 groundwater samples were collected in five phases: pre-culture, summer culture, immediately after summer harvest (IASH), winter culture and immediately after winter culture, respectively. The results revealed that the high value of TDS, Na, Cl and Br is observed in IASH, and also, the spatial distribution map confirmed that higher concentration is observed near to the creek and sea. Moreover, the abundance of these ions is in the following order: Na > Ca > Mg > k and Cl > HCO3 > SO4 > CO3 > NO3 > Br for different culture periods, respectively. Piper diagram depicts that the groundwater was controlled by ion exchange reactions. Further, Chadha’s classification revealed that the reverse ion exchange was the dominated feature, and it is supported by various ionic indices such as Na/Cl versus EC, (Ca + Mg) versus (SO4 + HCO3), (Na–Cl) versus (Ca + Mg–HCO3–SO4), (Ca + Mg) versus Cl and Na/Cl versus Cl, respectively. The result of factor analysis shows that most of the variations are elucidated by the seawater intrusion, rock–water interactions and anthropogenic activities during different culture periods. The spatial distribution map of factor scores clearly delineates that the positive values are observed near to the creek and sea and in that, shrimp farming area is not predominated. R-mode cluster analysis shows that groundwater quality does not vary extensively as a function of culture periods. Moreover, Q-mode classification consists of two clusters: the first cluster has a high saline water concentration comprising samples location near to the creek and sea. The second cluster mainly depends upon rock–water interactions and the majority of shrimp farming area are grouped under these categories. The above statements clearly indicate that groundwater parameters mainly depend upon the geological process and that shrimp farming cannot be targeted as the root cause for groundwater salinization.
Simulation of multiphase flow pattern, effective distance and filling ratio in hydraulic fracture
Authors: Pei Yuxin , Zhang Nanlin , Zhou Huaxing , Zhang Shengchuan , Zhang Wei , Zhang Jinhong
Published: November 2019

Hydraulic fracturing is a key measure to increase production and transform oil and gas reservoirs, which plays an important role in oil and gas field development. Common hydraulic fracturing is of inevitable bottlenecks such as difficulty in sand adding, sand plugging, equipment wearing and fracturing fluid damage. To solve these problems, a new type of fracturing technology, i.e., the self-propping fracturing technology is currently under development. Technically, the principle is to inject a self-propping fracturing liquid system constituting a self-propping fracturing liquid and a channel fracturing liquid into the formation. Self-propping fracturing liquid changes from liquid to solid through phase transition under the formation temperature, replacing proppants such as ceramic particles and quartz sand to achieve the purpose of propping hydraulic fractures. The flow pattern, effective distance and filling ratio of the self-propping fracturing liquid system in the hydraulic fracture are greatly affected by the parameters such as the fluid leak-off rate, surface tension and injection velocity. In this paper, a set of mathematical models for the flow distribution of self-propping fracturing liquid system considering fluid leak-off was established to simulate the flow pattern, effective distance, as well as filling ratio under different leak-off rates, surface tensions and injection velocities. The mathematical model was verified by physical experiments, proving that the mathematical model established herein could simulate the flow of self-propping fracturing liquid systems in hydraulic fractures. In the meantime, these results have positive impacts on the research of interface distribution of liquid–liquid two-phase flow.
Structural insights into substrate recognition by the type VII secretion system
Authors: Wang Shuhui , Zhou Kaixuan , Yang Xiaolin , Zhang Bing , Zhao Yao , Xiao Yu , Yang Xiuna , Yang Haitao , Guddat Luke W. , Li Jun , Rao Zihe
Published: November 2019

Type VII secretion systems (T7SSs) are found in many disease related bacteria includingMycobacterium tuberculosis(Mtb). ESX-1 [early secreted antigen 6 kilodaltons (ESAT-6) system 1] is one of the five subtypes (ESX-1~5) of T7SSs inMtb, where it delivers virulence factors into host macrophages during infection. However, little is known about the molecular details as to how this occurs. Here, we provide high-resolution crystal structures of the C-terminal ATPase3domains of EccC subunits from four differentMtbT7SS subtypes. These structures adopt a classic RecA-likeɑ/βfold with a conserved Mg-ATP binding site. The structure of EccCb1 in complex with the C-terminal peptide of EsxB identifies the location of substrate recognition site and shows how the specific signaling module “LxxxMxF” forMtbESX-1 binds to this site resulting in a translation of the bulge loop. A comparison of all the ATPase3structures shows there are significant differences in the shape and composition of the signal recognition pockets across the family, suggesting that distinct signaling sequences of substrates are required to be specifically recognized by different T7SSs. A hexameric model of the EccC-ATPase3is proposed and shows the recognition pocket is located near the central substrate translocation channel. The diameter of the channel is ~25-Å, with a size that would allow helix-bundle shaped substrate proteins to bind and pass through. Thus, our work provides new molecular insights into substrate recognition forMtbT7SS subtypes and also a possible transportation mechanism for substrate and/or virulence factor secretion.
Biogenic synthesis of magnesium oxide nanoparticles using Manihot esculenta (Crantz) leaf extract
Authors: Essien Enobong R. , Atasie Violette N. , Okeafor Anastecia O. , Nwude Davies O.
Published: November 2019

Recently, plant-mediated route or green approach for preparing metal and metal oxide nanoparticles has received enormous attention due to the ease of preparation and environmental friendliness when compared to physical and chemical methods. Plants contain phytochemicals which have been proposed as bio-reductants and capping agents for forming metal nanoparticles. Therefore, this study was aimed to prepare magnesium oxide nanoparticles (MgONPs) using aqueous extract of Manihot esculenta leaf. The leaf extract was first analyzed in a gas chromatograph–mass spectrometer (GC–MS) to examine the phytochemicals present. Then, the MgONPs formed were evaluated using UV–Visible (UV–Vis) spectrophotometry, scanning electron microscopy (SEM), energy-dispersive X-ray analysis (EDX), transmission electron microscopy (TEM), X-ray diffractometry (XRD) and Fourier transform infrared (FTIR) spectroscopy, to confirm the formation of MgONPs and to determine the morphology, elemental composition, shape and size, phase composition and nature of bonds present in the sample. Results revealed the formation of monodisperse, hexagonal shaped MgONPs of average size 36.7 nm having potentials for application in catalysis and as antimicrobial agent. Hence the process reported herein could be optimized for large-scale preparation of MgONPs.
Influence of tire-derived aggregates mixed with ballast on ground-borne vibrations
Authors: Fathali Masoud , Esmaeili Morteza , Moghadas Nejad Fereidoon
Published: November 2019

In this paper, the use of recycled tire-derived aggregates (TDA) mixed with ballast material is evaluated in order to reduce the train-induced ground-borne vibrations. For this purpose, a series of field vibration measurements has been carried out at an executed pilot track. The prepared ballast layer was mixed with different percentages of TDA in three sections. Moreover, another test section with pure ballast is considered as a reference. The vibrations generated by a motor-powered draisine at two different speeds are then recorded. Records of vibration data are provided using four seismometers placed once longitudinally and once transversely beside different sections. The outputs are then processed in both velocity–time and velocity–frequency domains. To verify the vibration mitigation performance of TDA in real operation conditions, field measurements under the passage of two planned passenger and freight trains are finally arranged. Results show that the best TDA mixture ratio, i.e., 10% by weight, can reduce the transmitted vibrations up to 12 dB for frequencies above 31.5 Hz. According to the obtained efficiency and the very low cost of the recycled materials, this solution can be considered as a competitive vibration countermeasure.
Prenatal Diagnosis of a Fetal Right Ventricular Diverticulum: A Case Report
Authors: Bansode Shalaka Arun , Balakrishnan Bijoy , Batra Meenu , Sreeja P. S. , Patil Swapneel N. , Gopinathan K. K.
Published: November 2019

Cardiac diverticulum is a rare anomaly. These are transmural localized protrusions, within the free wall of the ventricles. Diverticulum may be associated with pericardial effusion and complications such as pulmonary hypoplasia or hydrops fetalis. Pericardial effusion is the most frequently associated finding. Pericardial effusion should be considered as an indirect sign of the presence of cardiac diverticula. Delivery should be planned at a tertiary care center well equipped to deal with cardiac anomalies. Generally, the prognosis of the isolated cardiac diverticulum is excellent. We present a case of a prenatal diagnosis of right ventricular diverticulum at 20 weeks and 4 days of gestation associated with pericardial effusion. Spontaneous resolution of diverticulum and pericardial effusion was noted in the third trimester scan at around 35 weeks and 5 days. The baby was delivered at 39 weeks and 3 days of gestation by cesarean section for an obstetric indication. The baby was well at 1 year and 2 months of age at the time of writing. Fetal cardiac diverticulum if not associated with rhythm disturbance, signs of cardiac failure or other cardiac or extracardiac abnormality carries an excellent prognosis.
Vision, identity, and collective behavior change on pathways to sustainable futures
Authors: Chabay Ilan
Published: November 2019

The challenge facing humanity is to live sustainably within both the ecological and physical limits of our planet and the societal boundaries needed for social cohesion and well-being. This is fundamentally a societal issue, rather than primarily an environmental problem amenable to technological optimization. Implementing the global aspirations embodied in the sustainable development goals of the United Nations will require societal transformation largely through collective behavior change at multiple geographic scales and governance levels across the world. Narrative expressions of visions of sustainable futures and narrative expressions of identity provide important, but underutilized insights for understanding affordances and obstacles to collective behavior change. Analyzing affective narrative expressions circulating in various communities seeking to implement aspects of sustainability opens up the opportunity to test whether affectively prioritized agent-based models can lead to novel emergent dynamics of social movements seeking sustainable futures. Certain types of playful games also offer the means to observe collective behaviors, as well as providing boundary objects and learning environments to facilitate dialogs among diverse stakeholders. Games can be designed to stimulate learning throughout the life span, which builds capacity for continuing innovation for the well-being of societies in moving toward sustainable futures.
Catenary-Free Tramway Systems: Functional and Cost–Benefit Analysis for a Metropolitan Area
Authors: Guerrieri Marco
Published: November 2019

New tramway technologies such as “ground-level power supply systems” fit with the purpose of preserving historical heritage and urban environments of city centers. Such public transportation systems do not require a traditional air supply system (+ 750 V) and are therefore referred to as “catenary-free systems” (i.e., APS system, tramwave system, Primove system). Their implementation is becoming increasingly widespread, especially for cities with prestigious historical heritage, where high levels of environmental sustainability, capacity, reliability and safety standards are required. The study compares some of the most well-known and novel catenary-free systems for the creation of a 68-km tramway system, to be implemented in a metropolitan city. For each of the 7 new tramways, AIMSUN microsimulations were run to identify the most appropriate tramway track geometry and road section to minimize the interference with the vehicle activity. Moreover, for each system a financial and economic performance analysis has been carried out for an investment of about 869 million euros, while taking into account different scenarios of transportation demand. In addition, a cost–benefit analysis of the tramway lines investment project has been presented, including the calculation of the financial net present value, the economic net present value, rate of return of the investment and cost–benefit ratio. The analysis demonstrates that the APS ground-level power supply system is a proven alternative with greater economic and financial performance.
Feature Extraction-Based Real-Time Transient Stability Analysis
Authors: Saunders C. S. , Alamuti M. M. , Pisica I. , Taylor G. A. , Liu Y. , Liu J.
Published: November 2019

With increasing amounts of asynchronous generation being deployed to meet system energy demands, many transmission corridors may become constrained by angular stability criteria rather than steady-state thermal limitations. In such a system, it is paramount to have the capability to rapidly evaluate the stability margins of the system, particularly in a threatened post-fault state. The use of single machine equivalents (SIME) has been shown to be a powerful and flexible hybrid stability analysis method which can be computed directly from measured PMU data. However, due to the nature of the system reduction employed by SIME, as well as the method of extrapolation to estimate stability margins, there are many cases where the swing of the system is not accurately modelled by the traditional methods until a significant amount of data has been collected, at which point it may be too late to respond to the threat. In this paper, we address some of the limitations imposed by the traditional methods of reduction and prediction. We propose a method where rather than identifying a single critical SIME model for stability prediction, a spectrum of SIME representations of the post-fault system is developed, yielding a more timely and accurate estimate of post-fault stability conditions, through observation and feature extraction.
Uncertainty quantification of elastic material responses: testing, stochastic calibration and Bayesian model selection
Authors: Fitt Danielle , Wyatt Hayley , Woolley Thomas E. , Mihai L. Angela
Published: November 2019

Motivated by the need to quantify uncertainties in the mechanical behaviour of solid materials, we perform simple uniaxial tensile tests on a manufactured rubber-like material that provide critical information regarding the variability in the constitutive responses between different specimens. Based on the experimental data, we construct stochastic homogeneous hyperelastic models where the parameters are described by spatially independent probability density functions at a macroscopic level. As more than one parametrised model is capable of capturing the observed material behaviour, we apply Baye theorem to select the model that is most likely to reproduce the data. Our analysis is fully tractable mathematically and builds directly on knowledge from deterministic finite elasticity. The proposed stochastic calibration and Bayesian model selection are generally applicable to more complex tests and materials.
Aspect-based sentiment analysis using smart government review data
Authors: Alqaryouti Omar , Siyam Nur , Abdel Monem Azza , Shaalan Khaled
Published: November 2019

Digital resources such as smart applications reviews and online feedback information are important sources to seek customers’ feedback and input. This paper aims to help government entities gain insights on the needs and expectations of their customers. Towards this end, we propose an aspect-based sentiment analysis hybrid approach that integrates domain lexicons and rules to analyse the entities smart apps reviews. The proposed model aims to extract the important aspects from the reviews and classify the corresponding sentiments. This approach adopts language processing techniques, rules, and lexicons to address several sentiment analysis challenges, and produce summarized results. According to the reported results, the aspect extraction accuracy improves significantly when the implicit aspects are considered. Also, the integrated classification model outperforms the lexicon-based baseline and the other rules combinations by 5% in terms of Accuracy on average. Also, when using the same dataset, the proposed approach outperforms machine learning approaches that uses support vector machine (SVM). However, using these lexicons and rules as input features to the SVM model has achieved higher accuracy than other SVM models.
The clustering of risk behaviours in adolescence and health consequences in middle age
Authors: Akasaki Mifuyu , Ploubidis George B. , Dodgeon Brian , Bonell Chris P.
Published: November 2019

Introduction

There is increasing interest in the clustering of risk behaviours in adolescence. However, few studies have examined what clusters of risk behaviours exist among adolescents, their early‐life predictors, and their associations with later health.

Methods

We analysed data derived from 8754 participants (women 53.3%) in the 1970 British Cohort Study. Latent class analysis was used to identify clusters of risk behaviours at age 16. Regression modelling was then used to examine predictors of clusters and their consequences of risk behaviours and health outcomes at age 42.

Results

We identified two latent classes: a risky‐behaviour (men: 20.0%, women: 23.6%) and less‐risky‐behaviour class. Among men, those in the risky‐behaviour class were more likely to report smoking, multiple binge drinking, sexual debut before 16, involvement in fights and delinquency than were women. Membership in risky‐behaviour class was mainly predicted by sociodemographic and parental risk behaviours and monitoring. The risky‐behaviour class at age 16 was associated with the following outcome age 42: smoking status (more strongly among women), excessive alcohol consumption (more strongly among men), worse self‐rated health (more strongly among men), and psychological distress (only among women).

Conclusions

Engagement in multiple risk behaviours in adolescence is an important driver of health inequalities later in life. Early life intervention, for example via school‐based interventions, may be warranted for favourable lifelong health.
Simplicial complexity of surface groups
Authors: Borghini Eugenio , Minian Elías Gabriel
Published: November 2019

The simplicial complexity is an invariant for finitely presentable groups which was recently introduced by Babenko, Balacheff, and Bulteau to study systolic area. The simplicial complexity κ(G) was proved to be a good approximation of the systolic area σ(G) for large values of κ(G). In this paper we compute the simplicial complexity of all surface groups (both in the orientable and in the non-orientable case). This partially settles a problem raised by Babenko, Balacheff, and Bulteau. We also prove that κ(G * ℤ) = κ(G) for any surface group G. This provides the first partial evidence in favor of the conjecture of the stability of the simplicial complexity under free product with free groups. The general stability problem, both for simplicial complexity and for systolic area, remains open.
Before and After Bin ͑Ali : Comparing Two Attempts at Political Liberalization in Tunisia
Authors: Henneberg Sabina
Published: November 2019

This article examines changes in Tunisian political and societal life that allowed the country's second attempt at political opening (beginning in 2011) to introduce deeper, more long-lasting changes in its political system as compared to the first attempt (beginning in 1987).1The article argues that three such changes in particular—the increased role of regime moderates; the development of a network of civil society groups and political activists; and the use of inclusion, negotiation, and consensus—allowed the second attempt to unfold differently. The article also briefly discusses developments in the international context between the two attempts. The article contributes to existing studies of regime change and political transition as well as to historical considerations of Tunisian political developments more broadly.
Non-Communicable Diseases on the Rise in Sub-Saharan Africa, the Underappreciated Threat of a Dual Disease Burden
Authors: Mapesi Herry , Paris Daniel Henry
Published: November 2019

Abstract. In sub-Saharan Africa, the burden of non-communicable diseases (NCDs) remains under appreciated, but emerging evidence suggests it to be substantial. NCDs such as arterial hypertension, heart diseases, diabetes mellitus and chronic kidney diseases are especially relevant, and put additional strain on the already challenged health systems in this region. Moreover, NCDs appear to be associated with higher mortality and morbidity rates and are more common in younger population groups, in people from sub-Saharan Africa when compared to more developed countries. In this review, we summarize the current literature on the burden of NCDs in sub-Saharan Africa, and highlight the clinical implications of the most relevant etiologies, i.e. arterial hypertension, heart diseases, diabetes mellitus and chronic kidney diseases.
Generative Modeling of InSAR Interferograms
Authors: Rongier Guillaume , Rude Cody , Herring Thomas , Pankratius Victor
Published: November 2019

Interferometric synthetic aperture radar (InSAR) has become an essential technique to detect surface variations due to volcanoes, earthquakes, landslides, glaciers, and aquifers. However, Earth's ionosphere, atmosphere, vegetation, surface runoff, etc., introduce noise that requires post‐processing to separate its components. This work defines a generator to create interferograms that include each of those components. Our approach leverages deformation models with real data, either directly or through machine learning using geostatistical methods. These methods result from previous developments to more efficiently and better simulate spatial variables and could replace some statistical approaches used in InSAR processing. We illustrate the use of the generator to simulate an artificial interferogram based on the 2015 Illapel earthquake and discuss the improved performance offered by geostatistical approaches compared with classical statistical ones. The generator establishes a tool for multiple applications (1) to evaluate InSAR correction workflows in controlled scenarios with known ground truth; (2) to develop training sets and generative methods for machine learning algorithms; and (3) to educate on InSAR and its principles.
Earth's Van Allen Radiation Belts: From Discovery to the Van Allen Probes Era
Authors: Li W. , Hudson M.K.
Published: November 2019

Discovery of the Earth's Van Allen radiation belts by instruments flown on Explorer 1 in 1958 was the first major discovery of the Space Age. The observation of distinct inner and outer zones of trapped megaelectron volt (MeV) particles, primarily protons at low altitude and electrons at high altitude, led to early models for source and loss mechanisms including Cosmic Ray Albedo Neutron Decay for inner zone protons, radial diffusion for outer zone electrons and loss to the atmosphere due to pitch angle scattering. This scattering lowers the mirror altitude for particles in their bounce motion parallel to the Earth's magnetic field until they suffer collisional loss. A view of the belts as quasi‐static inner and outer zones of energetic particles with different sources was modified by observations made during the Solar Cycle 22 maximum in solar activity over 1989–1991. The dynamic variability of outer zone electrons was measured by the Combined Radiation Release and Effects Satellite launched in July 1990. This variability is caused by distinct types of heliospheric structure that vary with the solar cycle. The launch of the twin Van Allen Probes in August 2012 has provided much longer and more comprehensive measurements during the declining phase of Solar Cycle 24. Roughly half of moderate geomagnetic storms, determined by intensity of the ring current carried mostly by protons at hundreds of kiloelectron volts, produce an increase in trapped relativistic electron flux in the outer zone. Mechanisms for accelerating electrons of hundreds of electron volts stored in the tail region of the magnetosphere to MeVenergies in the trapping region are described in this review: prompt and diffusive radial transport and local acceleration driven by magnetospheric waves. Such waves also produce pitch angle scattering loss, as does outward radial transport, enhanced when the magnetosphere is compressed. While quasilinear simulations have been used to successfully reproduce many essential features of the radiation belt particle dynamics, nonlinear wave‐particle interactions are found to be potentially important for causing more rapid particle acceleration or precipitation. The findings on the fundamental physics of the Van Allen radiation belts potentially provide insights into understanding energetic particle dynamics at other magnetized planets in the solar system, exoplanets throughout the universe, and in astrophysical and laboratory plasmas. Computational radiation belt models have improved dramatically, particularly in the Van Allen Probes era, and assimilative forecasting of the state of the radiation belts has become more feasible. Moreover, machine learning techniques have been developed to specify and predict the state of the Van Allen radiation belts. Given the potential Space Weather impact of radiation belt variability on technological systems, these new radiation belt models are expected to play a critical role in our technological society in the future as much as meteorological models do today.
Longitudinal Variations of the Occurrence Probability of the Ionospheric F1 Layer Peak at Middle and High Latitudes
Authors: Li Zhenxing , Luan Xiaoli , Ren Dexin
Published: November 2019

This study focuses on the longitudinal variations of the ionospheric F1 layer occurrence probabilities from middle to high latitudes (40–70°) in the daytime in summer under low solar activity conditions. The ionospheric electron density profiles retrieved from the Constellation Observing System for Meteorology, Ionosphere, and Climate observations are used. The patterns of the F1 layer occurrence probabilities are constructed with latitude, longitude, and local time in both hemispheres. The results illustrate a new feature that the occurrence probability of the F1 layer changes with longitude in both hemispheres. Specifically, the F1 layer generally occurs more frequently in the longitudes within ~160°E–90°W at 40–70°N and within 0–150°E at 40–70°S. The peak occurrence probabilities occur around 150°W (>0.6) and 60°E (>0.8) in the Northern and Southern Hemispheres, respectively. The valleys with values near 0 are located at about 120°W at 40–70°S. A minor peak (~0.4) also occurs within ~0–90°E at 40–70°N. These locations depend on latitude and local time. A simulation using the Thermosphere Ionosphere Electrodynamics General Circulation Model （(TIEGCM）) reproduces the observed longitudinal pattern well. Further TIEGCM simulations show that the higher F1 layer occurrence probabilities can be largely explained by longitudinal variations of the O/N2 ratios and also that the dynamic processes, such as the neutral winds above the F1 layer, have additional contributions. These results reveal that the low O/N2 ratios deplete the ionospheric electron density above the F1 layer at middle and high latitudes and thus makes the F1 layer stand out.
Deposition Potential and Flow‐Response Dynamics of Emergent Sandbars in a Braided River
Authors: Alexander Jason S. , McElroy Brandon , Huzurbazar Snehalata , Elliott Caroline , Murr Marissa L.
Published: November 2019

Sandbars are ubiquitous in sandy‐braided rivers throughout the world. In the Great Plains of the United States, recovery and expansion of emergent sandbar habitat (ESH) has been a priority in lowland rivers where the natural extent of sandbars has been degraded. Recovery efforts are aimed at protection of populations of the interior least tern (Sterna antillarum) and piping plover (Charadrius melodus). But quantitative observations of deposition and erosion dynamics of populations of sandbars across long segments of rivers are rare. We present a three‐part case study which used Bayesian regression models to examine relations between hydrology, channel morphology, and ESH responses in the Platte River, eastern Nebraska. Logistic regression indicates presence of ESH is positively related to the Parker, (1976) stability criterion and a gradient in sediment transport mode, and negatively related to presence of vegetation. Hierarchical linear regression modeling shows direct coupling between sandbar top‐surface height and formative flood magnitude, but the gap between formative flood stage and sandbar top‐surface increases with increasing discharge. Finally, linear regression modeling of sandbar erosion demonstrates rates of ESH erosion are on the order of 10−1 ha/day during high‐flow periods and 10−2 during low‐flow periods, but sandbar persistence is largely a function of sandbar starting size. The collective observations highlight the importance of large floods (>3‐year recurrence) in creating very large sandbars that persist as high‐quality ESH over periods of years whereas lower‐magnitude, more‐frequent flood events create lower‐quality ESH that typically does not persist into the following nesting season.
The Effect of the 21 August 2017 Total Solar Eclipse on the Phase of VLF/LF Signals
Authors: Rozhnoi A. , Solovieva M. , Shalimov S. , Ouzounov D. , Gallagher P. , Verth G. , McCauley J. , Shelyag S. , Fedun V.
Published: November 2019

An experimental study of the phase and amplitude observations of sub‐ionospheric very low and low frequency (VLF/LF) signals is performed to analyze the response of the lower ionosphere during the 21 August 2017 total solar eclipse in the United States of America. Three different sub‐ionospheric wave paths are investigated. The length of the paths varies from 2,200 to 6,400 km, and the signal frequencies are 21.4, 25.2, and 40.75 kHz. The two paths cross the region of the total eclipse, and the third path is in the region of 40–60% of obscuration. None of the signals reveal any noticeable amplitude changes during the eclipse, while negative phase anomalies (from −33° to −95°) are detected for all three paths. It is shown that the effective reflection height of the ionosphere in low and middle latitudes is increased by about 3–5 km during the eclipse. Estimation of the electron density change in the lower ionosphere caused by the eclipse, using linear recombination law, shows that the average decrease is by 2.1 to 4.5 times.
Three Times Tectonics Changed the Climate
Authors: Barbuzano Javier
Published: November 2019

Fifty years after the birth of modern plate tectonics theory, a group of researchers highlights three key examples of how our planet’s shape-shifting outer layer has altered our climate.