bluuebunny/crossref_metadata_2025_split huggingface dataset:
Regression Rate Characterization of HTPB‐Paraffin Based Solid Fuels for Hybrid Rocket
Authors: Mahottamananda Sri Nithya , Kadiresh Nagarajan P. , Pal Yash 
Published: July 2020

AbstractHybrid rockets are entitled with unique features such as simplicity, thrust modulation, safety, and low cost compared to that of conventional liquid and solid rockets. Despite their distinct advantages, the polymeric solid fuels exhibit a low regression rate, which limits their potential applications for the various space missions. In this study, pure hydroxyl‐terminated polybutadiene (HTPB), paraffin wax, and blended HTPB‐paraffin solid fuels, namely 80P, 60P, 40P, 25P were characterized for ballistic performance. The viscosity, local regression rate, average regression rate and combustion chamber pressure of solid fuels were evaluated on a lab‐scale ballistic motor. It was found that the viscosity of blended fuels decreased with increasing the paraffin wt. % in the formulation. The local regression rates of blended fuels increased in the range of 0.53 mm/s to 1.58 mm/s at oxidizer mass flux range of 85 kg/m2s to 150 kg/m2s. The results indicate that increasing the wt.% of paraffin in the blend will enhance the average regression rate performance, besides suppressing the low‐pressure oscillations during steady‐state operation.
Design and validation of a cross‐specialty simulation‐based training course in basic robotic surgical skills
Authors: Scott Susanne I. , Dalsgaard Torur , Jepsen Jan Vibjerg , von Buchwald Christian , Andersen Steven Arild Wuyts 
Published: July 2020

AbstractBackgroundThe aim of this study was to design and validate a cross‐specialty basic robotic surgical skills training program on the RobotiX Mentor virtual reality simulator.MethodsA Delphi panel reached consensus on six modules to include in the training program. Validity evidence was collected according to Messick's framework with three performances in each simulator module by 11 experienced robotic surgeons and 11 residents without robotic surgical experience.ResultsFor five of the six modules, a compound metrics‐based score could significantly discriminate between the performances of novices and experienced robotic surgeons. Pass/fail levels were established, resulting in very few novices passing in their first attempt.ConclusionsThis validated course can be used for structured simulation‐based basic robotic surgical skills training within a mastery learning framework where the individual trainee can practice each module until they achieve proficiency and can continue training on other modalities and more specific to their specialty.
Automatic question generation
Authors: Last Mark , Danon Guy 
Published: July 2020

AbstractAutomatic generation of semantically well‐formed questions from a given text can contribute to various domains, including education, dialogues/interactive question answering systems, search engines, and more. It is well‐known as a challenging task, which involves the common obstacles of other natural language processing (NLP) activities. We start this advanced review with a brief overview of the most common automatic question generation (AQG) applications. Then we describe the main steps of a typical AQG pipeline, namely question construction, ranking, and evaluation. Finally, we discuss the open challenges of the AQG field that still need to be addressed by NLP researchers.This article is categorized under:
Algorithmic Development > Text Mining
From momentum amplituhedron boundaries to amplitude singularities and back
Authors: Ferro Livia , Łukowski Tomasz , Moerman Robert 
Published: July 2020

Abstract
The momentum amplituhedron is a positive geometry encoding tree-level scattering amplitudes in $$ \mathcal{N} $$
N
= 4 super Yang-Mills directly in spinor-helicity space. In this paper we classify all boundaries of the momentum amplituhedron ℳn, k and explain how these boundaries are related to the expected factorization channels, and soft and collinear limits of tree amplitudes. Conversely, all physical singularities of tree amplitudes are encoded in this boundary stratification. Finally, we find that the momentum amplituhedron ℳn, k has Euler characteristic equal to one, which provides a first step towards proving that it is homeomorphic to a ball.
Chiral gauge theory and gravity from unconventional supersymmetry
Authors: Alvarez Pedro D. , Valenzuela Mauricio , Zanelli Jorge 
Published: July 2020

AbstractFrom a gauge SU (2,2|2) model with broken supersymmetry, we construct an action for SU(2)×U (1) Yang-Mills theory coupled to gravity and matter in four dimensions. The connection components for AdS boosts and special conformal translations are auxiliary fields and their fixing reduces the theory to two distinct sectors: a vector-like gauge theory with general relativity and a chiral gauge theory where gravity drops out. We discuss some of the main classical features of the model such as the predicted tree level gauge couplings, cosmological constant value, mass-like terms and the Einstein equations.
Superradiant instability of black resonators and geons
Authors: Ishii Takaaki , Murata Keiju , Santos Jorge E. , Way Benson 
Published: July 2020

AbstractBlack resonators and geons in global AdS are rapidly rotating, low-energy solutions with a helical Killing field. We study the linear mode stability of equal angular momenta, five-dimensional black resonators and geons under scalar, electromagnetic, and gravitational perturbations. We find that black resonators are unstable to the superradiant instability, in agreement with previously known results. Perhaps surprisingly, many geons appear linearly stable, despite having an ergoregion. This apparent stability implies that geons are important long-lived, low-energy states in the dual gauge theory. However, we do find that geons are unstable within a certain range of parameter space. We comment on the nature of this instability and to its possible endpoints. We also report on new non-spinning oscillating geons, which we construct within a cohomogeneity two ansatz. Given the existing arguments that suggest our linear stability results may be extended nonlinearly, our findings indicate that most geons are generic and long-lived solutions.
Scalar and tensor neutrino interactions
Authors: Han Tao , Liao Jiajun , Liu Hongkai , Marfatia Danny 
Published: July 2020

Abstract
We constrain general Dirac neutrino interactions based on the Standard Model Effective Field Theory framework extended with right-handed neutrinos N (SMNEFT) using deep inelastic and coherent elastic neutrino scattering, nuclear beta decay, and meson decay data, and high energy electron-proton and proton-proton collider data. We compute the one-loop anomalous dimensions of the low-energy effective field theory (LEFT) below the electroweak scale and of SMNEFT above the electroweak scale. The tree-level matching between LEFT and SMNEFT is performed at the electroweak scale. Currently, the most stringent limits on scalar and tensor interactions arise from pseudoscalar meson decays and the LHC measurements at the per mille level. In the future, the upcoming High-Luminosity LHC (HL-LHC) has the potential to reach the 10−4 level and LHeC can play an important role under certain theoretical assumptions.
Point-of-care-ready nanoscale ISFET arrays for sub-picomolar detection of cytokines in cell cultures
Authors: Rani Dipti , Singh Yogesh , Salker Madhuri , Vu Xuan Thang , Ingebrandt Sven , Pachauri Vivek 
Published: July 2020

AbstractRapid and frequent screening of cytokines as immunomodulation agents is necessary for precise interventions in severe pathophysiological conditions. In addition to high-sensitivity detection of such analytes in complex biological fluids such as blood, saliva, and cell culture medium samples, it is also crucial to work out miniaturized bioanalytical platforms with potential for high-density integration enabling screening of multiple analytes. In this work, we show a compact, point-of-care-ready bioanalytical platform for screening of cytokines such as interleukin-4 (IL-4) and interleukin-2 (IL-2) based on one-dimensional ion-sensitive field-effect transistors arrays (nanoISFETs) of silicon fabricated at wafer-scale via nanoimprint lithography. The nanoISFETs biofunctionalized with receptor proteins alpha IL-4 and alpha IL-2 were deployed for screening cytokine secretion in mouse T helper cell differentiation culture media, respectively. Our nanoISFETs showed robust sensor signals for specific molecular binding and can be readily deployed for real-time screening of cytokines. Quantitative analyses of the nanoISFET-based bioanalytical platform was carried out for IL-4 concentrations ranging from 25 fg/mL (1.92 fM) to 2.5 μg/mL (192 nM), showing a limit of detection down to 3–5 fM, which was found to be in agreement with ELISA results in determining IL-4 concentrations directly in complex cell culture media.
Improving therapeutic potential of GDNF family ligands
Authors: Runeberg-Roos Pia , Penn Richard D 
Published: July 2020

AbstractThe last decade has been a frustrating time for investigators who had envisioned major advances in the treatment of Parkinson’s disease using neurotrophic factors. The first trials of glial cell line–derived neurotrophic factor for treating Parkinson’s disease were very promising. Later blinded control trials were disappointing, not reaching the predetermined outcomes for improvement in motor function. Consideration of the problems in the studies as well as the biology of the neurotrophins used can potentially lead to more effective therapies. Parkinson’s disease presents a multitude of opportunities for the cell biologist wanting to understand its pathology and to find possible new avenues for treatment.
Coronaviruses: a challenge of today and a call for extended human postmortem brain analyses
Authors: Riederer Peter , ter Meulen Volker 
Published: July 2020

AbstractWhile there is abounding literature on virus-induced pathology in general and coronavirus in particular, recent evidence accumulates showing distinct and deleterious brain affection. As the respiratory tract connects to the brain without protection of the blood–brain barrier, SARS-CoV-2 might in the early invasive phase attack the cardiorespiratory centres located in the medulla/pons areas, giving rise to disturbances of respiration and cardiac problems. Furthermore, brainstem regions are at risk to lose their functional integrity. Therefore, long-term neurological as well as psychiatric symptomatology and eventual respective disorders cannot be excluded as evidenced from influenza-A triggered post-encephalitic Parkinsonism and HIV-1 triggered AIDS–dementia complex. From the available evidences for coronavirus-induced brain pathology, this review concludes a number of unmet needs for further research strategies like human postmortem brain analyses. SARS-CoV-2 mirroring experimental animal brain studies, characterization of time-dependent and region-dependent spreading behaviours of coronaviruses, enlightening of pathological mechanisms after coronavirus infection using long-term animal models and clinical observations of patients having had COVID-19 infection are calling to develop both protective strategies and drug discoveries to avoid early and late coronavirus-induced functional brain disturbances, symptoms and eventually disorders. To fight SARS-CoV-2, it is an urgent need to enforce clinical, molecular biological, neurochemical and genetic research including brain-related studies on a worldwide harmonized basis.
COVID-19 Crisis: How to Avoid a ‘Lost Generation’
Authors: Tamesberger Dennis , Bacher Johann 
Published: July 2020

AbstractThe spread of the coronavirus has made economic conditions difficult in many economic areas and has led to skyrocketing youth unemployment in most European countries. On the basis of simple model calculations, we estimate the consequences of the COVID-19 shutdown on youth unemployment in the European Union for the year 2020. According to our estimations, youth unemployment will increase from 2.8 to 4.8 million. The youth unemployment rate will increase to 26%, and the number of young people not in education, employment and training (NEET) will increase from 4.7 to 6.7 million. Policymakers at the national and international level should react as quickly as possible and make great efforts to avoid these negative scenarios. We suggest the introduction of a new European Youth Guarantee to ensure fiscal relief for those countries that suffer the most economically. It should be financed jointly by the EU and the respective member states. We suggest a new formula-based co-financing model in order to guarantee solidarity between the member states.
One-step twin-screw extrusion process of cellulose fibers and hydroxyethyl cellulose to produce fibrillated cellulose biocomposite
Authors: Taheri Hesam , Hietala Maiju , Oksman Kristiina 
Published: July 2020

AbstractIn this work, the defibrillation of cellulose fibers (CF) in the presence of hydroxyethyl cellulose (HEC) within the one-step twin-screw extrusion (TSE) process was examined. The effect of the TSE on cellulose fiber size reduction as well as CF-HEC biocomposites properties were investigated. The results showed that the TSE of cellulose fiber-hydroxyethyl cellulose (CF-HEC) with different cellulose fiber contents (50, 65, and 80 wt%) resulted in partial defibrillation of the cellulose fibers. The fractionation test of the cellulose fibers confirmed that their size was reduced and some fibrillation was observed in microscopy studies. The maximum width reduction of 46% occurred with 80 wt% cellulose content. However, the partial width reduction was also observed with 50% and 65 wt% of cellulose contents. Based on rheological measurements, the shear-viscosity trend of CF-HEC dispersion abruptly dropped when higher fiber content (80 wt%) was extruded, which was related to the fibrillation of the cellulose fibers as well as the reduction of the length. The extruded CF-HEC materials (powder form) were compression molded to prepare the biocomposites with different cellulose fiber contents (50, 65, and 80 wt%). The extruded CF-HEC powders were diluted with addition extra HEC to make biocomposites with lower fiber content (20%, 30%, and 40 wt%) and compression molded to study how the size reduction of the cellulose fibers affected the mechanical properties of biocomposites. The results showed that the E-modulus improved from 0.4 GPa of the neat HEC to 1.6 GPa for the composite with 40 wt% CF. Interestingly, the tensile strength of CF-HEC biocomposite with 40 wt% confirmed a clear improvement from 9.8 to 26.6 MPa, confirming good interaction between HEC and CF.Graphic abstractPreparation (mixing, TSE, and hot-pressing) and characterization (FE-SEM, rheometry, and tensile test) of CF-HEC biocomposite
More perceived but not faster evolution of heat stress than temperature extremes in the future
Authors: Brouillet Audrey , Joussaume Sylvie 
Published: July 2020

AbstractGlobal warming is projected to intensify during the twenty-first century. Yet, only few studies investigate how global warming could be perceived by future populations. Here, we propose an assessment of how climate change could be perceived by combining climatological indicators. We analyse extremes of temperature (T99) and simplified Wet-Bulb Globe Temperature (WBGT99), a heat stress index assessing the combined effect of elevated temperature and humidity on the human body. The speed of change is defined for each year as the difference between the previous 20 years and the twenty upcoming years (i.e. with a moving baseline), and we assess how these speeds emerge from each last 20-year interannual variability. Using a set of 12 CMIP5 models, speeds of change of T99 and WBGT99 in 2080 are both twice as fast compared with current speeds in mid-latitudes, and by up to four times faster in the tropics under the RCP8.5 scenario. Warming accelerations are thus similar for T99 and WBGT99. However, these speeds in tropical regions in 2080 are projected to be 2.3 times larger than the last 20-year interannual variability for WBGT99, and only 1.5 to 1.8 times larger for T99. According to the models, the WBGT99 intensification will be more emergent from the recent year-to-year variability than the T99 warming. This analysis suggests that the accelerated warming of heat extremes will be felt more strongly by populations than current changes for RCP8.5, and that this evolution will be more perceived in heat stress than in temperature, particularly within the tropics.
Multi-cost Bounded Tradeoff Analysis in MDP
Authors: Hartmanns Arnd , Junges Sebastian , Katoen Joost-Pieter , Quatmann Tim 
Published: July 2020

AbstractWe provide a memory-efficient algorithm for multi-objective model checking problems on Markov decision processes (MDPs) with multiple cost structures. The key problem at hand is to check whether there exists a scheduler for a given MDP such that all objectives over cost vectors are fulfilled. We cover multi-objective reachability and expected cost objectives, and combinations thereof. We further transfer approaches for computing quantiles over single cost bounds to the multi-cost case and highlight the ensuing challenges. An empirical evaluation shows the scalability of our new approach both in terms of memory consumption and runtime. We discuss the need for more detailed visual presentations of results beyond Pareto curves and present a first visualisation approach that exploits all the available information from the algorithm to support decision makers.
On Chaos Behaviour of Nonlinear Lasota Equation in Lebesgue Space
Authors: Dawidowicz Antoni Leon , Poskrobko Anna 
Published: July 2020

AbstractWe concern the asymptotic behaviour of the dynamical systems induced by nonlinear Lasota equation. We study chaoticity in the sense of Devaney and strong stability of the system. In many articles authors consider the properties of the linear version of the equation. By the construction of the operator in the separable space, we can formulate the relations between the solutions of the linear equation and its nonlinear version in Lebesgue space. The aim of the paper is to present the detailed construction of the operator thanks to which, the study of simple relationships allows determining the chaotic behaviour of the nonlinear equation.
Land-use change and propagule pressure promote plant invasions in tropical rainforest remnants
Authors: Waddell Emily H. , Banin Lindsay F. , Fleiss Susannah , Hill Jane K. , Hughes Mark , Jelling Ahmad , Yeong Kok Loong , Ola Bernadus Bala , Sailim Azlin Bin , Tangah Joseph , Chapman Daniel S. 
Published: July 2020

AbstractContextIntact tropical rainforests are considered robust to plant invasions. However, land-use change alters the structure and species composition of native forest, opening up tropical landscapes to invasion. Yet, the relative roles of key drivers on tropical forest invasions remain little investigated.ObjectivesWe examine factors affecting plant invasion of rainforest remnants in oil-palm dominated landscapes in Sabah, Malaysian Borneo. We hypothesized that invasion is greater in highly fragmented landscapes, and in disturbed forests with lower native plant diversity (cf. old-growth rainforests).MethodsNative and exotic plants were surveyed in 47 plots at 17 forest sites, spanning gradients in landscape-scale fragmentation and local forest disturbance. Using partial least squares path-modelling, we examined correlations between invasion, fragmentation, forest disturbance, propagule pressure, soil characteristics and native plant community.ResultsWe recorded 6999 individuals from 329 genera in total, including eight exotic species (0–51% of individuals/plot, median = 1.4%) representing shrubs, forbs, graminoids and climbers. The best model (R2 = 0.343) revealed that invasion was correlated with disturbance and propagule pressure (high prevalence of exotic species in plantation matrix), the latter being driven by greater fragmentation of the landscape. Our models revealed a significant negative correlation between invasion and native tree seedlings and sapling community diversity.ConclusionsIncreasing landscape fragmentation promotes exotic plant invasion in remnant tropical forests, especially if local disturbance is high. The association between exotic species invasion and young native tree community may have impacts for regeneration given that fragmentation is predicted to increase and so plant invasion may become more prevalent.
The Effectiveness of a Community-Based Mentoring Program for Children Aged 5–11 Years: Results from a Randomized Controlled Trial
Authors: Axford Nick , Bjornstad Gretchen , Matthews Justin , Whybra Laura , Berry Vashti , Ukoumunne Obioha C. , Hobbs Tim , Wrigley Zoe , Brook Lucy , Taylor Rod , Eames Tim , Kallitsoglou Angeliki , Blower Sarah , Warner Georgina 
Published: July 2020

AbstractThe study, a two-arm, randomized controlled, parallel group, superiority trial, aimed to evaluate the implementation and effectiveness of a 12-month one-to-one volunteer mentoring program designed to improve behavioral and emotional outcomes in children aged 5 to 11 years who have teacher- and parent/carer-reported behavioral difficulties. Participants were 246 children (123 intervention, 123 control; mean age 8.4 years; 87% boys) in five sites in London, UK, scoring in the “abnormal” range on the teacher-rated Strengths and Difficulties Questionnaire (SDQ) Total Difficulties measure and in the “borderline” or abnormal range on the parent-rated SDQ Total Difficulties measure. Randomization on a 1:1 ratio took place using a computer-generated sequence and stratifying by site. Data collectors and statisticians were blind to participant allocation status. Outcome measures focused on parent- and teacher-rated child behavior and emotions, and child-rated self-perception and hope. Intention-to-treat analysis on all 246 randomized participants (using imputed data where necessary) showed that at post-intervention (16 months after randomization), there were no statistically significant effects on the primary outcome—parent-rated SDQ Total Difficulties (adjusted standardized mean difference = − 0.12; 95% CI: −0.38 to 0.13; p = 0.33)—or any secondary outcomes. Results from complier average causal effect (CACE) analysis using the primary outcome indicated the intervention was not effective for children who received the recommended duration of mentoring. Exploratory analyses found no sub-group effects on the primary outcome. The article concludes that the mentoring program had no effect on children’s behavior or emotional well-being, and that program content needs revising to satisfactorily address key risk and protective factors.
Delayed Graduation and Overeducation in Italy: A Test of the Human Capital Model Versus the Screening Hypothesis
Authors: Aina Carmen , Pastore Francesco 
Published: July 2020

AbstractExploiting the human capital versus screening hypothesis frameworks, this paper studies the link between delayed graduation and overeducation, and their effect on wages, by using the ISFOL-Plus data. The evidence lines towards predictions based on the signalling model. However, as to the determinants of overeducation the coefficient of delayed graduation is significant only for delays of 3 years or more and also controlling for the entire set of covariates. This suggests that delay conveys a signal of low skill.