bluuebunny/crossref_metadata_2025_split huggingface dataset:
Engineering the Coordination Sphere of Isolated Active Sites to Explore the Intrinsic Activity in Single-Atom Catalysts
Authors: Wu Xin , Zhang Huabin , Zuo Shouwei , Dong Juncai , Li Yang , Zhang Jian , Han Yu 
Published: June 2021

AbstractReducing the dimensions of metallic nanoparticles to isolated, single atom has attracted considerable attention in heterogeneous catalysis, because it significantly improves atomic utilization and often leads to distinct catalytic performance. Through extensive research, it has been recognized that the local coordination environment of single atoms has an important influence on their electronic structures and catalytic behaviors. In this review, we summarize a series of representative systems of single-atom catalysts, discussing their preparation, characterization, and structure–property relationship, with an emphasis on the correlation between the coordination spheres of isolated reactive centers and their intrinsic catalytic activities. We also share our perspectives on the current challenges and future research promises in the development of single-atom catalysis. With this article, we aim to highlight the possibility of finely tuning the catalytic performances by engineering the coordination spheres of single-atom sites and provide new insights into the further development for this emerging research field.
Finite Strain Constitutive Modelling of Shape Memory Alloys Considering Partial Phase Transformation with Transformation-Induced Plasticity
Authors: Scalet Giulia , Karakalas Anargyros , Xu Lei , Lagoudas Dimitris 
Published: June 2021

AbstractThis paper presents a unified modelling effort to describe partial phase transformation during cyclic thermo-mechanical loading in Shape Memory Alloys (SMA). To this purpose, a three-dimensional (3D) finite strain constitutive model considering TRansformation-Induced Plasticity (TRIP) is combined with a modified hardening function to enable the accurate and efficient prediction of partial transformations during cyclic thermo-mechanical loading. The capabilities of the proposed model are demonstrated by predicting the behavior of the material under pseudoelastic and actuation operation using finite element analysis. Numerical results of the modified model are presented and compared with the original model without considering the partial transformation feature as well as with uniaxial actuation experimental data. Various aspects of cyclic material behavior under partial transformation are analyzed and discussed for different SMA systems.
Connecting Activity Implementation Characteristics to Student Buy-In Toward and Utilization of Formative Assessments Within Undergraduate Biology Courses
Authors: Brazeal Kathleen R. , Brown Tanya L. , Couch Brian A. 
Published: June 2021

AbstractWhile formative assessments (FAs) can facilitate learning within undergraduate STEM courses, their impact likely depends on many factors, including how instructors implement them, whether students buy-in to them, and how students utilize them. FAs have many different implementation characteristics, including what kinds of questions are asked, whether questions are asked before or after covering the material in class, how feedback is provided, how students are graded, and other logistical considerations. We conducted 38 semi-structured interviews with students from eight undergraduate biology courses to explore how various implementation characteristics of in-class and out-of-class FAs can influence student perceptions and behaviors. We also interviewed course instructors to provide context for understanding student experiences. Using thematic analysis, we outlined various FA implementation characteristics, characterized the range of FA utilization behaviors reported by students, and identified emergent themes regarding the impact of certain implementation characteristics on student buy-in and utilization. Furthermore, we found that implementation characteristics have combined effects on student engagement and that students will tolerate a degree of “acceptable discomfort” with implementation features that contradict their learning preferences. These results can aid instructor reflection and guide future research on the complex connections between activity implementation and student engagement within STEM disciplines.
Wing component allocation for a morphing variable span of tapered wing using finite element method and topology optimisation – application to the UAS-S4
Authors: Elelwi M. , Calvet T. , Botez R.M. , Dao T.-M. 
Published: June 2021

AbstractThis work presents the Topology Optimisation of the Morphing Variable Span of Tapered Wing (MVSTW) using a finite element method. This topology optimisation aims to assess the feasibility of internal wing components such as ribs, spars and other structural components. This innovative approach is proposed for the telescopic mechanism of the MVSTW, which includes the sliding of the telescopically extended wing into the fixed wing segment. The optimisation is performed using the tools within ANSYS Mechanical, which allows the solving of topology optimisation problems. This study aims to minimise overall structural compliance and maximise stiffness to enhance structural performance, and thus to meet the structural integrity requirements of the MVSTW. The study evaluates the maximum displacements, stress and strain parameters of the optimised variable span morphing wing in comparison with those of the original wing. The optimised wing analyses are conducted on four wingspan extensions, that is, 0%, 25%, 50% and 75%, of the original wingspan, and for different flight speeds to include all flight phases (17, 34, 51 and 68m/s, respectively). Topology optimisation is carried out on the solid wing built with aluminium alloy 2024-T3 to distribute the wing components within the fixed and moving segments. The results show that the fixed and moving wing segments must be designed with two spar configurations, and seven ribs with their support elements in the high-strain area. The fixed and moving wing segments’ structural weight values were reduced to 16.3 and 10.3kg from 112 to 45kg, respectively. The optimised MVSTW was tested using different mechanical parameters such as strains, displacements and von Misses stresses. The results obtained from the optimised variable span morphing wing show the optimal mechanical behaviour and the structural wing integrity needed to achieve the multi-flight missions.
COVID-19 Pandemic: Knowledge, Attitude, and Perception of Medical Students Toward the Novel Coronavirus Disease
Authors: Elsayed Emara Hesham , Alhindi Abdallah Ahmoud , Orebi Hisham Ahmed , Kabbash Ibrahim Ali , Elghazally Noha M. 
Published: June 2021

AbstractBackground:Medical students are vulnerable to infection by the coronavirus. Their awareness of the disease is crucial for their safety and for the management of the epidemic by spreading supportive information in their communities. The aim of this study was to assess coronavirus disease 2019 (COVID-19)-related knowledge, attitude, and preventive practices among Egyptian medical students.Methods:We conducted a cross-sectional study from the beginning of April to June 2020; a total of 439 undergraduate medical students (1st to 6th academic years) were assessed using an online questionnaire. The questionnaire consisted of 33 questions, including 5 items regarding socio-demographic features, 23 items concerning COVID-19 related knowledge, 2 items regarding attitude, and 3 items related to preventive measures.Results:We observed an acceptable level of knowledge (74.3%) among the sample studied. Preclinical and female students were significantly more optimistic as 69.1% expected successful control of COVID-19, and 48.9% predicted that Egypt will win the fight against COVID-19. The majority of participants reported wearing a facemask in public places as a preventive measure (56.7%).Conclusions:Egyptian medical students had an acceptable level of knowledge, positive attitude, and good practices of preventive measures regarding the COVID-19 virus. There is no significant difference in almost all items of knowledge, attitude, and practices in relation to gender or academic grade.
Centre–Province Relations in Personalist Autocracies: Explaining the Emergence and Survival of Powerful Provincial Leaders
Authors: Tolstrup Jakob , Souleimanov Emil 
Published: June 2021

AbstractWe have limited knowledge of how the insecure environment characteristic of personalist dictatorships affects the behaviour of provincial leaders. In this article, we argue that such provincial leaders face a trade-off: either they can keep a low profile but remain vulnerable to the capriciousness of the ruler (the acquiescent strategy), or they can gamble and try to build a power base of their own as a defence against the whims of the dictator (the power-accruing strategy). Next, we specify three contextual conditions, each of which makes provincial leaders more likely to choose and succeed with a power-accruing strategy, which in turn allows them to rule their province with an iron fist. Finally, empirically, we illustrate our arguments through a number of example cases and an in-depth study of a contemporary, very powerful provincial leader in a personalist authoritarian regime: Ramzan Kadyrov, leader of the Chechen Republic within Vladimir Putin's Russia.
Populism and Polarization in Comparative Perspective: Constitutive, Spatial and Institutional Dimensions
Authors: Roberts Kenneth M. 
Published: June 2021

AbstractPolarization may be the most consistent effect of populism, as it is integral to the logic of constructing populist subjects. This article distinguishes between constitutive, spatial and institutional dimensions of polarization, adopting a cross-regional comparative perspective on different subtypes of populism in Europe, Latin America and the US. It explains why populism typically arises in contexts of low political polarization (the US being a major, if partial, outlier), but has the effect of sharply increasing polarization by constructing an anti-establishment political frontier, politicizing new policy or issue dimensions, and contesting democracy's institutional and procedural norms. Populism places new issues on the political agenda and realigns partisan and electoral competition along new programmatic divides or political cleavages. Its polarizing effects, however, raise the stakes of political competition and intensify conflict over the control of key institutional sites.
Studies of distance one surgeries on the lens space L(p, 1)
Authors: WU ZHONGTAO , YANG JINGLING 
Published: June 2021

AbstractIn this paper, we study distance one surgeries between lens spaces L(p, 1) with p ≥ 5 prime and lens spaces L(n, 1) for $$n \in \mathbb{Z}$$ and band surgeries from T (2, p) to T (2, n). In particular, we prove that L(n, 1) is obtained by a distance one surgery from L(5, 1) only if n=±1, 4, ±5, 6 or ±9, and L(n, 1) is obtained by a distance one surgery from L(7, 1) if and only if n=±1, 3, 6, 7, 8 or 11.
Posttraumatic stress disorder and growth: Examination of joint trajectories in children and adolescents
Authors: Zhou Xiao , Wu Xinchun 
Published: June 2021

AbstractPositive health endpoints are not the opposite of negative endpoints. Previous studies examining posttraumatic stress disorders (PTSD) and posttraumatic growth (PTG) trajectories have overlooked the co-existence of PTSD and PTG, making it difficult to accurately distinguish individuals with various posttraumatic presentations, causing the effects of targeted interventions to be discounted. To fill this gap, the current study sought to examine joint PTSD and PTG trajectories in children and adolescents. Eight hundred and seventy-six Chinese children and adolescents were recruited to complete self-report questionnaires 6, 12, and 18 months after the Ya'an earthquake. Multiple-process growth mixture modeling analysis was used to test the study proposal. Five distinct joint PTSD and PTG trajectory types were found: recovery, growth, struggling, resistant, and delayed symptoms. Female students and students who felt trapped or fearful were more likely to be in the struggling group, and students who experienced injury to themselves or family members were more likely to belong to the delayed symptom group. These findings suggest that postdisaster psychological services should be provided to relieve delayed symptoms in individuals who experience injury to themselves or their family members, and individuals in the struggling group should be supported to achieve growth.
COVID-19: A Crisis of Borders
Authors: Boucher Anna , Hooijer Gerda , King Desmond , Napier Isabelle , Stears Marc 
Published: June 2021

ABSTRACTThe public health crisis of COVID-19 has compounded preexisting crises of democratic stability and effective governance, spurring debate about the ability of developed democracies to respond effectively to emergencies confronting their citizens. These crises, much discussed in recent political science, are joined by a further crisis which complicates and reinforces them: A migration crisis. Widespread travel and immigration restrictions instigated the largest and fastest decline in global human mobility in modern history, and COVID-19 may fundamentally change immigration over the longer term.The migration crisis heightens three crucial and preexisting concerns within immigration policy: the role of visa design; the status of undocumented migrants and other migrants without recourse to public funds; and the interaction of immigration and the labor market policy. It could reinforce a rising tide of nationalism and anti-immigrant sentiment, protectionist sentiment within labor-market policy debates, and a K-shaped recovery in migration patterns.
Slip Model of the 2020 Yutian (Northwestern Tibetan Plateau) Earthquake Derived From Joint Inversion of InSAR and Teleseismic Data
Authors: Li Qi , Li Chengtao , Tan Kai , Lu Xiaofei , Zuo Xiao 
Published: June 2021

AbstractInterferometric synthetic aperture radar and teleseismic P‐wave data were combined to investigate the source rupture characteristics of the 2020 Mw 6.3 Yutian, China, earthquake. We first utilized the near‐field displacements together with 29 broadband teleseismic P waveforms to investigate the uniform slip model by using a Bayesian bootstrap optimization nonlinear inversion method to resolve the nucleation point location, origin time and fault geometrical parameters. Based on these results, the kinematic rupture process of the earthquake was inverted. We conclude that the 2020 Yutian earthquake occurred on a west‐dipping blind normal fault with a dip of ∼60° at the junction of Bayan Har block (BHB) and western Kunlun block (WKB). The rupture nucleation point was located at longitude = 82.435°E, latitude = 35.619°N, and a depth of 6.377 km, making it shallower than estimated from other point source inversions. The earthquake started at 21:05:20 UTC on June 25, 2020 and was delayed by ∼2.07 s compared with GeoForschungsZentrum. The rupture lasted for ∼12 s, with a total seismic moment of ∼3.28 × 1018 Nm, corresponding to a moment magnitude of 6.3. The slip was mainly confined between ∼3.0 and 9.0 km in depth and the peak slip was ∼1.40 m, which occurred at a depth of ∼6.377 km. The slip was predominantly normal slip with slight right‐lateral strike‐slip components, which agrees with the southeastward movement of the BHB relative to the WKB.
Analysis of the Daytime Urban Heat Island Mechanism in East China
Authors: Li Congyuan , Zhang Ning 
Published: June 2021

AbstractUrban heat islands (UHIs) are one of the most typical changes to surface climate induced by human activities, which manifest as higher temperatures in urban areas than in their surroundings. In this study, we synthetically analyzed spatiotemporal features of daytime surface UHI intensity in east China over the period from 2009 to 2018 carried out with several offline simulations coupled with four land‐use data sets, and identified the causes of UHIs with two attribution methods. The results indicate that spatial variations of summer daytime UHI intensity in east China are dominated by variations in the efficiency of evaporating water (∼3°C) between urban and rural areas. Geographic variations of winter UHI intensity mainly depend on the urban‐rural contrast of heat storage capacity (∼1°C). Additionally, we found that forest‐covered rural areas have an extremely higher convection efficiency than urban areas and nonforest rural landscapes, resulting in a remarkable contribution to summer daytime UHI intensity (∼6°C). However, rural areas largely comprising croplands and grasslands evaporate water more efficiently, expanding summer daytime UHI intensity by approximately 3°C. The prominent capacity of heat storage in nonforest vegetation rural areas accounts for 1°C warming of winter daytime UHI intensity. The major discrepancy between the two attribution methods lies in the evapotranspiration performances of forest‐covered rural lands. Furthermore, the inter‐comparison of several modeling experiments for land‐use data sets suggests that the disparity in UHI intensity could increase by up to 0.4°C, which may exceed 1°C at the local scale.
Comparison of Bubble Shape Model Results With Textural Analysis: Implications for the Velocity Profile Across a Volcanic Conduit
Authors: Ohashi Masatoshi , Ichihara Mie , Kennedy Ben , Gravley Darren 
Published: June 2021

AbstractTube pumice, which is characterized by aligned elongated bubbles, is valuable for our understanding of the shear field in a volcanic conduit. Most previous studies interpreted that tube pumice forms through simple shear, assuming a parabolic velocity profile across a volcanic conduit. However, simple shear cannot account for the observation that tube pumice is rare in plinian fall deposits but frequent in ignimbrites at the Taupō volcano, if the pyroclastic flows that formed them erupted through a wider vent and had a lower average shear rate. Here, we analyze the dynamics of bubble deformation that occurred during the 232 CE Taupō eruption by combining a bubble deformation model with a conduit flow model. The results indicate that bubble deformation is largely controlled by the velocity profile across a conduit. If the conduit flow has a parabolic velocity profile, the amount of bubble elongation is unrealistic compared to the Taupō fall deposits. It is more likely that the conduit flow has a plug‐like velocity profile due to viscous heating. We numerically confirmed that bubbles in the plug‐like flow are subject mainly to pure shear and accumulate less strain for elongation. We also calculated a viscous heating flow of the ignimbrite phase. We modeled a wider conduit, which suppresses viscous heating around the conduit walls and causes a higher proportion of the conduit to experience parabolic flow, compared to the plinian phase. The increased proportion of a parabolic profile may explain the high frequency of elongated bubbles in the ignimbrite phase pumice.
Salinity Effect on Trace Element Incorporation in Cultured Shells of the Large Benthic Foraminifer Operculinaammonoides
Authors: Hauzer Hagar , Evans David , Müller Wolfgang , Rosenthal Yair , Erez Jonathan 
Published: June 2021

AbstractThe ratio of sodium to calcium in the shells of foraminifera (Na/Cashell) has been experimentally calibrated as a proxy for past ocean Ca concentrations (Hauzer et al., 2018, https://doi.org/10.1016/j.epsl.2018.06.004). In parallel, it has been suggested that Na/Cashell could be used as a proxy for paleo‐salinity. In this study, we determined the extent to which foraminiferal Na/Ca (and other elements) change with salinity for the shallow‐dwelling large benthic foraminifer Operculina ammonoides, an extant relative of the abundant Eocene Nummulites. The culture experiment was conducted under four salinities between 33 and 43 psu. Shell chemistry was measured by LA‐ICPMS with the newly precipitated CaCO3 identified by a 135Ba‐spike added to the experimental seawater. Na/Cashell, Mg/Cashell and Li/Cashell in O. ammonoides increased slightly with salinity, while Sr/Cashell showed no resolvable change. The change in Na/Cashell due to salinity was small (∼1.4%/psu) compared to the changes in this ratio caused by varying seawater calcium concentrations (Casw) with a sensitivity of ∼5%/(mmol kg−1) Casw. Moreover, the change in salinity in most regions of the past open oceans is minor compared to the large secular variations in Casw during the Phanerozoic (10–40 mmol kg−1). Thus, if at all, paleo‐salinity may be reconstructed based on Na/Cashell only for samples younger than Casw residence time (∼1 Myr). Furthermore, both regional and global changes in ocean salinity over geological time do not pose a significant complication for the use of Na/Cashell as a proxy for past changes in seawater calcium concentrations.
Planar liquid crystal polarization optics for near-eye displays
Authors: Lu Yan-qing , Li Yan 
Published: June 2021

AbstractAs a promising candidate for next-generation mobile platforms, virtual reality and augmented reality have the potential to revolutionize the way we perceive and interact with various types of digital information. In the meantime, ultrathin planar liquid crystal polarization optics are enabling a new evolutionary trend in near-eye displays. A recent invited review paper published in eLight provides an insightful review on liquid crystal optical elements and their applications toward AR and VR.
Improving clinical paediatric research and learning from COVID-19: recommendations by the Conect4Children expert advice group
Authors: Ramanan Athimalaipet V. , Modi Neena , de Wildt Saskia N. ,   c4c Learning from COVID-19 Group, Aurich Beate , Bakhtadze Sophia , Sirvent Francisco J. Bautista , Cabañas Fernando , Campbell Lisa , Casanova Michaela , Charlton Philippa , Crandall Wallace , Eichler Irmgard , Fregonese Laura , Hawcutt Daniel B. , Iveli Pablo , Jaki Thomas , Jocic-Jakubi Bosanka , Johnson Mats , Kaguelidou Florentina , Karadag Bülent , Kelly Lauren E. , Lim Ming , Moreno Carmen , Neumann Eva , Ollivier Cécile , Oualha Mehdi , Raffaeli Genny , Ribeiro Maria A. , Roilides Emmanuel , de Rojas Teresa , Simón Alba Rubio San , Ruperto Nicolino , Scarpa Maurizio , Schwab Matthias , Siapkara Angeliki , Singh Yogen , Smits Anne , Striano Pasquale , Urru Silvana A. M. , Vivarelli Marina , de Wildt Saskia , Zivkoviz Zorica 
Published: June 2021

Abstract
Background
The COVID-19 pandemic has had a devastating impact on multiple aspects of healthcare, but has also triggered new ways of working, stimulated novel approaches in clinical research and reinforced the value of previous innovations. Conect4children (c4c, www.conect4children.org) is a large collaborative European network to facilitate the development of new medicines for paediatric populations, and is made up of 35 academic and 10 industry partners from 20 European countries, more than 50 third parties, and around 500 affiliated partners.

Methods
We summarise aspects of clinical research in paediatrics stimulated and reinforced by COVID-19 that the Conect4children group recommends regulators, sponsors, and investigators retain for the future, to enhance the efficiency, reduce the cost and burden of medicines and non-interventional studies, and deliver research-equity.

Findings
We summarise aspects of clinical research in paediatrics stimulated and reinforced by COVID-19 that the Conect4children group recommends regulators, sponsors, and investigators retain for the future, to enhance the efficiency, reduce the cost and burden of medicines and non-interventional studies, and deliver research-equityWe provide examples of research innovation, and follow this with recommendations to improve the efficiency of future trials, drawing on industry perspectives, regulatory considerations, infrastructure requirements and parent–patient–public involvement. We end with a comment on progress made towards greater international harmonisation of paediatric research and how lessons learned from COVID-19 studies might assist in further improvements in this important area.