bluuebunny/crossref_metadata_2025 huggingface dataset:
Applying test case prioritization to software microbenchmarks
Authors: Laaber Christoph , Gall Harald C. , Leitner Philipp
Published: September 2021

Regression testing comprises techniques which are applied during software evolution to uncover faults effectively and efficiently. While regression testing is widely studied for functional tests, performance regression testing, e.g., with software microbenchmarks, is hardly investigated. Applying test case prioritization (TCP), a regression testing technique, to software microbenchmarks may help capturing large performance regressions sooner upon new versions. This may especially be beneficial for microbenchmark suites, because they take considerably longer to execute than unit test suites. However, it is unclear whether traditional unit testing TCP techniques work equally well for software microbenchmarks. In this paper, we empirically study coverage-based TCP techniques, employing total and additional greedy strategies, applied to software microbenchmarks along multiple parameterization dimensions, leading to 54 unique technique instantiations. We find that TCP techniques have a mean APFD-P (average percentage of fault-detection on performance) effectiveness between 0.54 and 0.71 and are able to capture the three largest performance changes after executing 29% to 66% of the whole microbenchmark suite. Our efficiency analysis reveals that the runtime overhead of TCP varies considerably depending on the exact parameterization. The most effective technique has an overhead of 11% of the total microbenchmark suite execution time, making TCP a viable option for performance regression testing. The results demonstrate that the total strategy is superior to the additional strategy. Finally, dynamic-coverage techniques should be favored over static-coverage techniques due to their acceptable analysis overhead; however, in settings where the time for prioritzation is limited, static-coverage techniques provide an attractive alternative.
Graph representations in genetic programming
Authors: Françoso Dal Piccol Sotto Léo , Kaufmann Paul , Atkinson Timothy , Kalkreuth Roman , Porto Basgalupp Márcio
Published: September 2021

Graph representations promise several desirable properties for genetic programming (GP); multiple-output programs, natural representations of code reuse and, in many cases, an innate mechanism for neutral drift. Each graph GP technique provides a program representation, genetic operators and overarching evolutionary algorithm. This makes it difficult to identify the individual causes of empirical differences, both between these methods and in comparison to traditional GP. In this work, we empirically study the behaviour of Cartesian genetic programming (CGP), linear genetic programming (LGP), evolving graphs by graph programming and traditional GP. By fixing some aspects of the configurations, we study the performance of each graph GP method and GP in combination with three different EAs: generational, steady-state and $$(1+\lambda )$$

(
1
+
λ
)

. In general, we find that the best choice of representation, genetic operator and evolutionary algorithm depends on the problem domain. Further, we find that graph GP methods can increase search performance on complex real-world regression problems and, particularly in combination with the ($$1 + \lambda$$

1
+
λ

) EA, are significantly better on digital circuit synthesis tasks. We further show that the reuse of intermediate results by tuning LGP’s number of registers and CGP’s levels back parameter is of utmost importance and contributes significantly to better convergence of an optimization algorithm when solving complex problems that benefit from code reuse.
Influence of lactide vs glycolide composition of poly (lactic-co-glycolic acid) polymers on encapsulation of hydrophobic molecules: molecular dynamics and formulation studies
Authors: Dobhal Anurag , Srivastav Ashu , Dandekar Prajakta , Jain Ratnesh
Published: September 2021

The work demonstrates the preparation of PLGA (PLGA 50:50, PLGA 75:25) nanoparticles, to encapsulate a hydrophobic molecule (coumarin-6), using the microreactor-based continuous process. The formulations were characterized using dynamic light scattering and transmission electron microscopy to determine their size, homogeneity, zeta potential, and surface morphology. The resulting nanoparticles were safe to the CHO cells (≈80% cell survival), at the concentration of ≤600 µg/mL and were successfully taken up by the cells, as demonstrated using confocal microscopy. Moreover, imaging flow cytometry confirmed that the nanoparticles were internalized in 73.96% of the cells. Furthermore, molecular dynamics simulation and docking studies were carried out to explore the effect of polymer chain length of PLGA and lactide vs glycolide (LA:GA) ratio on their compatibility with the coumarin-6 molecules and to study the coiling and flexibility of PLGA in the presence of coumarin-6 molecules. Flory–Huggins interaction parameter (χ) was calculated for polymer chains of varying lengths and LA:GA ratio, with respect to coumarin-6. χ parameter increased with increase in polymer chain length, which indicated superior interaction of coumarin-6 with the smaller chains. Amongst all the polymeric systems, PLGA55 exhibited the strongest interaction with coumarin-6, for all the chain lengths, possibly because of their homogeneous spatial arrangements and superior binding energy. PLGA27 showed better compatibility compared to PLGA72 and PGA, whereas PLA-based polymers exhibited the least compatibility. Analysis of the radius of gyration of the polymer chains in the polymer–coumarin-6 complexes, at the end of molecular dynamics run, exhibited that the polymer chains displayed varying coiling behavior and flexibility, depending upon the relative concentrations of the polymer and coumarin-6. Factors like intra-chain interactions, spatial arrangement, inter-chain binding energies, and polymer–coumarin-6 compatibility also influenced the coiling and flexibility of polymer chains.
Towards a neo-configurational theory of intrinsic motivation
Authors: Swiatczak Martyna Daria
Published: September 2021

This research seeks to improve our understanding of how intrinsic motivation is instantiated. Three motivation theories, flow theory, self-determination theory, and empowerment theory, have informed our understanding of the foundations of intrinsic motivation at work. Taken jointly, they suggest six causal factors for intrinsic motivation: (1) perceived competence, (2) perceived challenge, (3) perceived autonomy, (4) perceived impact, (5) perceived social relatedness, and (6) perceived meaningfulness. Integrating different theoretical perspectives, I employ a case-based configurational approach and conduct coincidence analyses on survey data from a German public utility to analyse the nuanced interplay of these six causal factors for intrinsic motivation. My data show that high perceived meaningfulness or high perceived autonomy is sufficient for high perceived intrinsic motivation and at least one of the two conditions must be present. Further, my findings reveal a common cause structure in which perceived impact is not a causal factor for intrinsic motivation but an additional outcome factor. Subsequent analyses shed light on possible roles of the remaining proposed causal factors by drawing a tentative causal chain structure. The results of this study enhance our understanding of the causal complexity underlying the formation of intrinsic motivation.
Machine Learning Can Assign Geologic Basin to Produced Water Samples Using Major Ion Geochemistry
Authors: Shelton Jenna L. , Jubb Aaron M. , Saxe Samuel W. , Attanasi Emil D. , Milkov Alexei V. , Engle Mark , Freeman Philip A. , Shaffer Christopher A. , Blondes Madalyn S.
Published: September 2021

Understanding the geochemistry of waters produced during petroleum extraction is essential to informing the best treatment and reuse options, which can potentially be optimized for a given geologic basin. Here, we used the US Geological Survey’s National Produced Waters Geochemical Database (PWGD) to determine if major ion chemistry could be used to classify accurately a produced water sample to a given geologic basin based on similarities to a given training dataset. Two datasets were derived from the PWGD: one with seven features but more samples (PWGD7), and another with nine features but fewer samples (PWGD9). The seven-feature dataset, prior to randomly generating a training and testing (i.e., validation) dataset, had 58,541 samples, 20 basins, and was classified based on total dissolved solids (TDS), bicarbonate (HCO3), Ca, Na, Cl, Mg, and sulfate (SO4). The nine-feature dataset, prior to randomly splitting into a training and testing (i.e., validation) dataset, contained 33,271 samples, 19 basins, and was classified based on TDS, HCO3, Ca, Na, Cl, Mg, SO4, pH, and specific gravity. Three supervised machine learning algorithms—Random Forest, k-Nearest Neighbors, and Naïve Bayes—were used to develop multi-class classification models to predict a basin of origin for produced waters using major ion chemistry. After training, the models were tested on three different datasets: Validation7, Validation9, and one based on data absent from the PWGD. Prediction accuracies across the models ranged from 23.5 to 73.5% when tested on the two PWGD-based datasets. A model using the Random Forest algorithm predicted most accurately compared to all other models tested. The models generally predicted basin of origin more accurately on the PWGD7-based dataset than on the PWGD9-based dataset. An additional dataset, which contained data not in the PWGD, was used to test the most accurate model; results suggest that some basins may lack geochemical diversity or may not be well described, while others may be geochemically diverse or are well described. A compelling result of this work is that a produced water basin of origin can be determined using major ions alone and, therefore, deep basinal fluid compositions may not be as variable within a given basin as previously thought. Applications include predicting the geochemistry of produced fluid prior to drilling at different intervals and assigning historical produced water data to a producing basin.
Kinetics of alpha-synuclein depletion in three brain regions following conditional pan-neuronal inactivation of the encoding gene (Snca) by tamoxifen-induced Cre-recombination in adult mice
Authors: Chaprov Kirill D. , Lysikova Ekaterina A. , Teterina Ekaterina V. , Buchman Vladimir L.
Published: September 2021

Conditional pan-neuronal inactivation of the Snca gene in 2-month old male and female mice causes dramatic decrease in the level of the encoded protein, alpha-synuclein, in three studied brain regions, namely cerebral cortex, midbrain and striatum, 12 weeks after the last injection of tamoxifen. Kinetics of alpha-synuclein depletion is different in these brain regions with a longer lag period in the cerebral cortex where this protein is normally most abundant. Our results suggest that efficient post-developmental pan-neuronal knockout of alpha-synuclein in adult, i.e. 5- to 6-month old, animals, could be achieved by tamoxifen treatment of 2-month old mice carrying loxP-flanked Snca gene and expressing inducible Cre-ERT2 recombinase under control of the promoter of neuron-specific enolase (NSE) gene.
Epigenetic clock and methylation studies in vervet monkeys
Authors: Jasinska Anna J. , Haghani Amin , Zoller Joseph A. , Li Caesar Z. , Arneson Adriana , Ernst Jason , Kavanagh Kylie , Jorgensen Matthew J. , Mattison Julie A. , Wojta Kevin , Choi Oi-Wa , DeYoung Joseph , Li Xinmin , Rao Andrew W. , Coppola Giovanni , Freimer Nelson B. , Woods Roger P. , Horvath Steve
Published: September 2021

DNA methylation-based biomarkers of aging have been developed for many mammals but not yet for the vervet monkey (Chlorocebus sabaeus), which is a valuable non-human primate model for biomedical studies. We generated novel DNA methylation data from vervet cerebral cortex, blood, and liver using highly conserved mammalian CpGs represented on a custom array (HorvathMammalMethylChip40). We present six DNA methylation-based estimators of age: vervet multi-tissue epigenetic clock and tissue-specific clocks for brain cortex, blood, and liver. In addition, we developed two dual species clocks (human-vervet clocks) for measuring chronological age and relative age, respectively. Relative age was defined as ratio of chronological age to maximum lifespan to address the species differences in maximum lifespan. The high accuracy of the human-vervet clocks demonstrates that epigenetic aging processes are evolutionary conserved in primates. When applying these vervet clocks to tissue samples from another primate species, rhesus macaque, we observed high age correlations but strong offsets. We characterized CpGs that correlate significantly with age in the vervet. CpG probes that gain methylation with age across tissues were located near the targets of Polycomb proteins SUZ12 and EED and genes possessing the trimethylated H3K27 mark in their promoters. The epigenetic clocks are expected to be useful for anti-aging studies in vervets.
Tipping Cascades in a Multi-patch System with Noise and Spatial Coupling
Authors: Mallela Abhishek , Hastings Alan
Published: September 2021

Forecasting tipping points in spatially extended systems is a key area of interest to ecologists. A slowly declining spatially distributed population is an important example of an ecological system that could exhibit a cascade of tipping points. Here, we develop a spatial two-patch model with environmental stochasticity that is slowly forced through population collapse, in the presence of changing environmental conditions. We begin with a basic spatial model, then introduce a fast–slow version of the model using geometric singular perturbation theory, followed by the inclusion of stochasticity. Using the spectral density of the fluctuating subpopulation in each patch, we derive analytic expressions for candidate indicators of population extinction and evaluate their performance through a simulation study. We find that coupling and spatial heterogeneity decrease the magnitude of the proposed indicators in coupled populations relative to isolated populations. Moreover, the degree of coupling dictates the trends in summary statistics. We conclude that this theory may be applied to other contexts, including the control of invasive species.
Jenseits von Professionswissen: Eine systematische Überblicksarbeit zu einstellungs- und motivationsbezogenen Einflussfaktoren auf die Nutzung digitaler Technologien im Unterricht
Authors: Bürger Nicoletta , Haselmann Sina , Baumgart Joanna , Prinz Gabriele , Girnat Boris , Meisert Anke , Menthe Jürgen , Schmidt-Thieme Barbara , Wecker Christof
Published: September 2021

Neben dem Professionswissen werden in verschiedenen Kompetenzmodellen der Lehrkräfteprofessionalität auch einstellungs- und motivationsbezogene Variablen berücksichtigt. Die vorliegende Arbeit gibt einen systematischen Literaturüberblick zum empirischen Forschungsstand bezüglich deren Rolle für die Nutzung digitaler Technologien im Unterricht. Anknüpfend an Theorien der Technologieakzeptanz werden zunächst relevante potenzielle Einflussfaktoren auf die beabsichtigte und tatsächliche Nutzung digitaler Technologien im Unterricht identifiziert und mit Hilfe der Theory of Planned Behavior systematisiert. Daran anknüpfend werden empirische Befunde aus englischsprachigen Veröffentlichungen aus den Jahren 2010 bis 2020 dargestellt. Der Überblick liefert Hinweise, dass die untersuchten einstellungs- und motivationsbezogenen Einflussfaktoren überwiegend erwartungskonform mit der Nutzung digitaler Technologien im Unterricht zusammenhängen. Forschungslücken zeigen sich unter anderem bezüglich der Rolle einstellungs- und motivationsbezogener Einflussfaktoren für Aspekte der Unterrichtsqualität sowie Interventionsmöglichkeiten zur Beeinflussung dieser Variablen.
Temptation shapes dishonesty and can alter working memory
Authors: Pittarello Andrea , Fratescu Marcella , Mathôt Sebastiaan
Published: September 2021

This study shows that participants tend to remember an ambiguous, directional cue as biased towards stimuli associated with a high reward that can be attained dishonestly. Participants saw eight digits presented in a circular arrangement. On some trials, they were asked to report the digit (“Target Digit”) indicated by a jittery cue that was slightly biased in the direction of another digit (“Second Cued Digit”), which was either higher or lower than the Target Digit. Participants were paid based on the reported digit (higher digits meant higher pay) and not based on the accuracy of their report. In this setting, they could make self-serving mistakes by dishonestly reporting the Second Cued Digit when it was higher than the Target Digit. Replicating prior work, participants frequently made such self-serving mistakes. On other trials, after the digits disappeared, participants were asked to reproduce the direction of the jittery cue, without receiving any pay. Results showed that that participants’ reports of the cue were more biased toward high-rewarding digits than low-rewarding digits. This research provides preliminary evidence of a link between attention, dishonesty, and memory, offering an important constraint for theories in behavioral ethics.
Animal husbandry between the Roman times and the High Middle Ages in central Europe: a biometrical analysis of cattle, sheep and pig
Authors: Grau-Sologestoa Idoia , Ginella Francesca , Marti-Grädel Elisabeth , Stopp Barbara , Deschler-Erb Sabine
Published: September 2021

This paper presents a meta-analysis of biometrical data of cattle (Bos taurus), sheep (Ovis aries), and pig (Sus domesticus), with a diachronic, long-term approach (first–twelfth centuries AD) and at a large regional scale (Switzerland and adjacent areas of France), with the aim of looking at changes in animal husbandry during the transition between Roman times and the Early Middle Ages. With this in mind, a comprehensive biometrical analysis is carried out, on the basis of the log-ratio technique (or logarithmic size index — LSI). The results show an increase of the size of domesticates during the Late Roman period, as well as a long period of size decrease in the subsequent centuries. The possible reasons behind this size decrease are discussed, focusing on three factors: a genetic change, less direct control over feeding and breeding, and changing patterns of herd sex ratios. We argue that these changes should be seen as an efficient adaptation of animal husbandry strategies to broader social, economic, and political transformations.
Changes in traditional building materials: the case of gypsum in Northern Spain
Authors: Bel-Anzué Pedro , Elert Kerstin
Published: September 2021

The rural and monumental architecture of Northern Spain gives testimony of the wide-ranging constructive possibilities of traditional gypsum for exterior and structural applications. However, today, gypsum is only used for finishing purposes. By combining a bibliographic review with local visits/interviews and experimental gypsum calcinations, we were able to document traditional processing methods and analyze the factors responsible for the decline of exterior and structural gypsum use. Obtained results are also valid for other European countries and contribute to a better understanding of the technical peculiarities of traditional gypsum, hopefully reviving traditional processing techniques to produce compatible and sustainable conservation materials.
Advances in Research on Chemical Constituents and Their Biological Activities of the Genus Actinidia
Authors: Ma Jin-Tao , Li Da-Wei , Liu Ji-Kai , He Juan
Published: September 2021

Kiwi, a fruit from plants of the genusActinidia, is one of the famous fruits with thousand years of edible history. In the past twenty years, a great deal of research has been done on the chemical constituents of theActinidiaspecies. A large number of secondary metabolites including triterpenoids, flavonoids, phenols, etc. have been identified from differents parts ofActinidiaplants, which exhibited significant in vitro and in vivo pharmacological activities including anticancer, anti-inflammatory, neuroprotective, anti-oxidative, anti-bacterial, and anti-diabetic activities. In order to fully understand the chemical components and biological activities ofActinidiaplants, and to improve their further research, development and utilization, this review summarizes the compounds extracted from different parts ofActinidiaplants since 1959 to 2020, classifies the types of constituents, reports on the pharmacological activities of relative compounds and medicinal potentials.
Fabrication and microstructure evolution of Csf/ZrB2-SiC composites via direct ink writing and reactive melt infiltration
Authors: Lu Jun , Ni Dewei , Liao Chunjing , Zhou Haijun , Jiang Youlin , Chen Bowen , Zou Xuegang , Cai Feiyan , Ding Yusheng , Dong Shaoming
Published: September 2021

Fiber damage and uniform interphase preparation are the main challenges in conventional short fiber reinforced ceramic matrix composites. In this work, we develop a novel processing route in fabrication of short carbon fiber reinforced ZrB2-SiC composites (Csf/ZrB2-SiC) overcoming the above two issues. At first, Csf preforms with oriented designation and uniform PyC/SiC interphase are fabricated via direct ink writing (DIW) of short carbon fiber paste followed by chemical vapor infiltration. After that, ZrB2 and SiC are introduced into the preforms by slurry impregnation and reactive melt infiltration, respectively. Microstructure evolution and optimization of the composites during fabrication are investigated in detail. The as-fabricated Csf/ZrB2-SiC composites have a bulk density of 2.47 g/cm3, with uniform weak interphase and without serious fiber damage. Consequently, non-brittle fracture occurs in the Csf/ZrB2-SiC composites with widespread toughening mechanisms such as crack deflection and bridging, interphase debonding, and fiber pull-out. This work provides a new opportunity to the material design and selection of short fiber reinforced composites.
Forging connections, pursuing social justice: a tribute to Maarten Bavinck’s conceptual and institution-building contributions to maritime studies
Authors: Scholtens Joeri , Johnson Derek , Jentoft Svein , Ros-Tonen Mirjam , Chuenpagdee Ratana , Gupta Joyeeta , Kraan Marloes , Menon Ajit , Roth Dik
Published: September 2021

This paper is written in recognition of the contributions that Maarten Bavinck has made to the field of maritime studies and for the inspiration that he has been for many. It is hard to separate Maarten’s academic and institution-building contributions from his personal qualities, particularly his interest in human relationships. Maarten’s aptitude for building bridges between people, ideas, and institutions has allowed him to connect people in larger knowledge generation and action projects and forge new conceptual bridges. In addition to reflecting shortly on Maarten's key role in establishing the Centre for Maritime Research (MARE) as a institutional anchor in maritime studies, this paper reviews on some of his important and original contributions to four academic domains: legal pluralism, interactive governance, the study of fisheries conflicts, and the environment-development interface. Common threads across these domains include his long-term commitment to meticulous fieldwork in South Asia that grounds his work so firmly, his focus on achieving a more socially just use of marine and coastal resources, and his pragmatic approach that has led to original connections across distinct conceptual and institutional fields.
Touristifizierung von Religion und Spiritualisierung von Tourismus. Erkundungen am Beispiel von religiösen Wanderwegen im Schwarzwald
Authors: Sammet Kornelia , Karstein Uta
Published: September 2021

In den letzten Jahren hat religiös konnotiertes Reisen über den kirchlichen Kontext hinaus an Bedeutung gewonnen. Dies findet seinen Ausdruck auch in touristischen Angeboten und Marketingstrategien. Der Beitrag bearbeitet anhand des Wanderns als einer spezifischen Form der touristischen Bewegung in landschaftlich reizvoller Umgebung die Frage, wie durch den Tourismus auf Religiöses in Form von Artefakten, Orten und Wegen Bezug genommen und Religion touristisch recodiert wird, wodurch religiös gefärbte touristische Räume erzeugt werden.

Der Beitrag verfolgt eine differenzierungstheoretischen Perspektive, nach der Tourismus als ein sozialer Zusammenhang verstanden wird, der an vielen gesellschaftlichen Teilbereichen partizipiert und sie in kommunikativer Hinsicht mit Rückgriff auf den Code „erlebnisförmige Erholung“ einer Recodierung unterzieht. Anhand von touristischem Material, das Wanderwege im Schwarzwald mit religiösen Wegmarken bewirbt, werden mit sequenzanalytischen Verfahren zwei typische kommunikative Muster von touristischen Bezugnahmen auf Religiöses rekonstruiert, nämlich die Musealisierung und die Kommodifizierung des Religiösen. In umgekehrter Perspektive werden religiöse Recodierungen des Touristischen analysiert, die als Kommunikation über Religion zu ihrer Kulturalisierung beitragen oder mit religiöser Kommunikation eine (Re‑)Spiritualisierung von Landschaft betreiben. Abschließend werden die Fallanalysen zusammengeführt und ihre Anschlussfähigkeit an aktuelle religionssoziologische Konzepte diskutiert.
Quasisymmetric orbit-flexibility of multicritical circle maps
Authors: DE FARIA EDSON , GUARINO PABLO
Published: September 2021

Two given orbits of a minimal circle homeomorphism f are said to be geometrically equivalent if there exists a quasisymmetric circle homeomorphism identifying both orbits and commuting with f. By a well-known theorem due to Herman and Yoccoz, if f is a smooth diffeomorphism with Diophantine rotation number, then any two orbits are geometrically equivalent. It follows from the a priori bounds of Herman and Świątek, that the same holds if f is a critical circle map with rotation number of bounded type. By contrast, we prove in the present paper that if f is a critical circle map whose rotation number belongs to a certain full Lebesgue measure set in
$(0,1)$
, then the number of equivalence classes is uncountable (Theorem 1.1). The proof of this result relies on the ergodicity of a two-dimensional skew product over the Gauss map. As a by-product of our techniques, we construct topological conjugacies between multicritical circle maps which are not quasisymmetric, and we show that this phenomenon is abundant, both from the topological and measure-theoretical viewpoints (Theorems 1.6 and 1.8).
Glider automata on all transitive sofic shifts
Authors: KOPRA JOHAN
Published: September 2021

For any infinite transitive sofic shift X we construct a reversible cellular automaton (that is, an automorphism of the shift X) which breaks any given finite point of the subshift into a finite collection of gliders traveling into opposing directions. This shows in addition that every infinite transitive sofic shift has a reversible cellular automaton which is sensitive with respect to all directions. As another application we prove a finitary version of Ryan’s theorem: the automorphism group
$\operatorname {\mathrm {Aut}}(X)$
contains a two-element subset whose centralizer consists only of shift maps. We also show that in the class of S-gap shifts these results do not extend beyond the sofic case.
Analytic classification of germs of parabolic antiholomorphic diffeomorphisms of codimension k
Authors: GODIN JONATHAN , ROUSSEAU CHRISTIANE
Published: September 2021

We investigate the local dynamics of antiholomorphic diffeomorphisms around a parabolic fixed point. We first give a normal form. Then we give a complete classification including a modulus space for antiholomorphic germs with a parabolic fixed point under analytic conjugacy. We then study some geometric applications: existence of real analytic invariant curves, existence of holomorphic and antiholomorphic roots of holomorphic and antiholomorphic parabolic germs, and commuting holomorphic and antiholomorphic parabolic germs.
The pitfalls of investigating rotational flows with the Euler equations
Authors: Smith Warren R. , Wang Qianxi
Published: September 2021

Small viscous effects in high-Reynolds-number rotational flows always accumulate over time to have a leading-order effect. Therefore, the high-Reynolds-number limit for the Navier–Stokes equations is singular. It is important to investigate whether a solution of the Euler equations can approximate a real flow at large Reynolds number. These facts are often overlooked and, as a result, the Euler equations are used to simulate laminar rotational flows at large Reynolds number. Based on the Fredholm alternative, an asymptotic perturbation theory is described to establish secularity conditions determined by viscosity for an inviscid solution to approximate a real viscous fluid. Four important classical inviscid solutions are investigated using the theory with the following conclusions. The Stuart cats’ eyes and Mallier–Maslowe vortices are inconsistent with any real fluid at high Reynolds number; whereas Hill's spherical vortex is confirmed to be consistent with a steady state in the spherical core region and the Lamb–Chaplygin dipole is found to be consistent with a quasi-steady state in the circular core region. These solutions have been widely used for analysing the stability of vortex flows and wakes, and their interactions with shock waves or bubbles. Serendipitously, we have revealed an original exact solution of the Navier–Stokes equations which is time dependent, has non-zero nonlinear convective terms and is restricted to a finite domain with the decay rate depending on dipole radius.
SECOND HANKEL DETERMINANT OF LOGARITHMIC COEFFICIENTS OF CONVEX AND STARLIKE FUNCTIONS
Authors: KOWALCZYK BOGUMIŁA , LECKO ADAM
Published: September 2021

We begin the study of Hankel matrices whose entries are logarithmic coefficients of univalent functions and give sharp bounds for the second Hankel determinant of logarithmic coefficients of convex and starlike functions.
Enslaved Muslim Sufi Saints in the Nineteenth-Century Sahara: The Life of Bilal Ould Mahmoud
Authors: Esseissah Khaled
Published: September 2021

This article centers on the life of Bilal Ould Mahmoud, an enslaved man who became a spiritual authority in the nineteenth-century Sahara. It examines how Bilal's piety allowed him to rise to prominence in a hierarchical context that subjugated him to an inferior position. Yet what makes him so fascinating to study is his ability to achieve the highest station as a Sufi saint without being attached to a Sufi order. Using Bilal's case, this article makes two important contributions to the historiographies of Sufism and slavery. First, it brings fresh perspectives to the studies of Sufism outside of ṭarīqa (Sufi orders). Second, it contributes to the studies of Saharan slavery by exploring enslaved Muslims’ experiences beyond the practice of illicit magic, and also as part of how they exercised their saintly authority as empowered agents. In the process, it analyzes the interplay among Islam, race, and slavery in the nineteenth-century Sahara.
Crisis as Opportunity: Exploring the African Union's Response to COVID-19 and the Implications for Its Aspirational Supranational Powers
Authors: Fagbayibo Babatunde , Owie Udoka Ndidiamaka
Published: September 2021

The COVID-19 pandemic has proved challenging to states and regional organizations, exposing gaps in political leadership as well as in the preparedness of economic and public healthcare systems. As states and organizations contend with the pandemic, the African Union's response in this regard, thus far, indicates the imperative of enhanced multilateralism. Its response also provides a template for endowing the organization with assertive, binding powers over its member states and, as such, achieving its supranational aspirations. In this respect, this article argues that the African Union's display of progressive internationalism, swiftness of action, agency and legitimacy in combatting the coronavirus pandemic are elements that can be applied in sharpening its processual quest for supranationalism.
Embedding in Shawi narrations: A quantitative analysis of embedding in a post-colonial Amazonian indigenous society
Authors: Rojas-Berscia Luis Miguel , Lehecka Tomas , Claassen Simon A. , Peute A. A. K. , Escobedo Moisés Pinedo , Escobedo Segundo Pinedo , Tangoa Abimael Huiñapi , Pizango Elio Yumi
Published: September 2021

In this article, we provide the first quantitative account of the frequent use of embedding in Shawi, a Kawapanan language spoken in Peruvian Northwestern Amazonia. We collected a corpus of ninety-two Frog Stories (Mayer 1969) from three different field sites in 2015 and 2016. Using the glossed corpus as our data, we conducted a generalised mixed model analysis, where we predicted the use of embedding with several macrosocial variables, such as gender, age, and education level. We show that bilingualism (Amazonian Spanish-Shawi) and education, mostly restricted by complex gender differences in Shawi communities, play a significant role in the establishment of linguistic preferences in narration. Moreover, we argue that the use of embedding reflects the impact of the mestizo1 society from the nineteenth century until today in Santa Maria de Cahuapanas, reshaping not only Shawi demographics but also linguistic practices. (Post-colonial societies, Amazonian linguistics, Kawapanan, Shawi, embedding, language variation and change, contact linguistics)*
Why don't cockatoos have war songs?
Authors: Moser Cody , Ackerman Jordan , Dayer Alex , Proksch Shannon , Smaldino Paul E.
Published: September 2021

We suggest that the accounts offered by the target articles could be strengthened by acknowledging the role of group selection and cultural niche construction in shaping the evolutionary trajectory of human music. We argue that group level traits and highly variable cultural niches can explain the diversity of human song, but the target articles' accounts are insufficient to explain such diversity.
Musical features emerging from a biocultural musicality
Authors: Popescu Tudor , Oesch Nathan , Buck Bryony
Published: September 2021

Savage et al. make a compelling case, Mehr et al. less so, for social bonding and credible signalling, respectively, as the main adaptive function of human musicality. We express general advocacy for the former thesis, highlighting: (1) overlap between the two; (2) direct versus derived biological functions, and (3) aspects of music embedded in cultural evolution, for example, departures from tonality.
Social bonding and credible signaling hypotheses largely disregard the gap between animal vocalizations and human music
Authors: Zentner Marcel
Published: September 2021

Mehr et al. propose a theory of the evolution music that can potentially account for most animal vocalizations as precursors to human music. Therein lies its appeal but also its Achilles' heel, for the wider the range of animal vocalizations treated as premusical expressions, the wider the gap to human music. Here, I offer a few critical observations and constructive suggestions that I hope will help the authors strengthen their case.
Foundational assumption reasonable but uncertain
Authors: Wright Rex A. , Mlynski Christopher
Published: September 2021

We offer thoughts on Shadmehr and Ahmed's foundational assumption that behavioral intensity (vigor) is proportional to the perceived value of outcomes driving behavior (incentives). The assumption is reasonable considering classical motivational thought and scholarship in related literatures but called into question by an influential contemporary theory of motivation by Brehm. Brehm's theory suggests that the assumption is warranted in some, but not all, performance circumstances. Furthermore, proportionality between vigor and value might be generated through a deliberative goal-setting process rather than through intrinsic neural linkages.
The emergence and evolution of International Relations studies in postcolonial South Korea
Authors: Seo Jungmin , Cho Young Chul
Published: September 2021

This study investigates how International Relations (IR) as an academic discipline emerged and evolved in South Korea, focusing on the country's peculiar colonial and postcolonial experiences. In the process, it examines why South Korean IR has been so state-centric and positivist (American-centric), while also disclosing the ways in which international history has shaped the current state of IR in South Korea, institutionally and intellectually. It is argued that IR intellectuals in South Korea have largely reflected the political arrangement of their time, rather than demonstrate academic independence or leadership for its government and/or civil society, as they have navigated difficult power structures in world politics. Related to this, it reveals South Korean IR's twisted postcoloniality, which is the absence – or weakness – of non-Western Japanese colonial legacies in its knowledge production/system, while its embracing the West/America as an ideal and better model of modernity for South Korea's security and development. It also reveals that South Korean IR's recent quest for building a Korean School of IR to overcome its Western dependency appears to be in operation within a colonial mentality towards mainstream American IR.
Lernergebnisse und individuelle Prozesse des Physik-Lernens mit auditiven und visuellen Hinweisen
Authors: Hurzlmeier Maleen , Watzka Bianca , Hoyer Christoph , Girwidz Raimund , Ertl Bernhard
Published: September 2021

Zusammenfassung. Die vorliegende Studie untersuchte im Kontext einer videobasierten Lernumgebung, inwieweit Personen durch die Darbietung von auditiven und visuellen Hinweisen beim Lernen komplexer Inhalte unterstützt werden können. Vor dem Hintergrund von Theorien des multimedialen Lernens wurden die Wirkungen der Hinweise auf kognitive Belastung, Lernerfolg sowie Blickbewegungen der Lernenden analysiert. In einem experimentellen Zwei-Gruppen-Design mit Vor- und Nachtest lernten 46 Teilnehmerinnen und Teilnehmer mithilfe visueller ( n = 23) oder auditiver ( n = 23) Unterstützung. Den Lerngegenstand bildeten Skizzen elektrischer Schaltungen, die als kognitives Werkzeug zur Lösung physikalischer Aufgaben eingesetzt werden. Es ergaben sich zwischen den Versuchsbedingungen keine signifikanten Unterschiede in Belastungserleben und Lernerfolg (.00 ≤ ηp2 ≤ .08). Allerdings waren Maße der kognitiven Belastung signifikante Prädiktoren des Lernerfolgs. Es zeigten sich auch bedeutsame Einflüsse des Vorwissens auf Wissensabruf ( R2 = .213) und Wissenstransfer ( R2 = .257). Im Rahmen qualitativer Auswertungen wurden zudem die Blickpfade von Personen mit niedrigem und hohem Vorwissen verglichen. Hier zeigte sich in beiden Modalitäten bei Personen mit niedrigem Vorwissen eher ein detailorientiertes Blickmuster auf Einzelelemente der Schaltungen und bei Personen mit hohem Vorwissen eher ein ganzheitlich orientiertes Blickmuster über das System von Schaltungen. In Bezug auf die vorwissensabhängigen Unterschiede in den Blickmustern und die Komplexität des Lerngegenstandes erscheinen sowohl eine zeitliche als auch eine instruktionale Adaptierbarkeit der Lernumgebung für Lernende mit wenig Vorwissen in beiden Hinweismodalitäten sinnvoll. Für die zukünftige Forschung bietet es sich im Sinne eines Mixed-Method-Ansatzes an, Prozesse und Ergebnisse des Lernens stärker aufeinander zu beziehen, um zu tieferen Erkenntnissen über die Nutzung und Wirkung instruktionaler Hinweise zu gelangen.
Tools for Improved Drought and Flood Response
Authors: Wu Huan , Lettenmaier Dennis , Tang Qiuhong , Ward Philip
Published: September 2021

A new book presents recent advances in the modeling and remote sensing of droughts and floods of use to emergency response organizations and policy makers on a global scale.
Heterogenous Late Holocene Climate in the Eastern Mediterranean—The Kocain Cave Record From SW Turkey
Authors: Jacobson Matthew J. , Flohr Pascal , Gascoigne Alison , Leng Melanie J. , Sadekov Aleksey , Cheng Hai , Edwards R. Lawrence , Tüysüz Okan , Fleitmann Dominik
Published: September 2021

Palaeoclimate variability must be constrained to predict the nature and impacts of future climate change in the Eastern Mediterranean. Here, we present a late Holocene high‐resolution multiproxy data set from Kocain Cave, the first of its kind from SW Turkey. Regional fluctuations in effective‐moisture are recorded by variations in magnesium, strontium, phosphorous and carbon isotopes, with oxygen isotopes reacting to changes in precipitation and effective‐moisture. The new record shows a double‐peak of arid conditions at 1150 and 800 BCE, a wet period 330–460 CE followed by a rapid shift to dry conditions 460–830 CE, and a dry/wet Medieval Climate Anomaly/Little Ice Age pattern. Large discrepancies exist between Turkish records and the Kocain record, which shares more similarities with other Eastern Mediterranean coastal records. Heterogeneity of regional climate and palaeoclimate proxy records are emphasized.
Diffusion‐Free Scaling in Rotating Spherical Rayleigh‐Bénard Convection
Authors: Wang Guiquan , Santelli Luca , Lohse Detlef , Verzicco Roberto , Stevens Richard J. A. M.
Published: September 2021

Direct numerical simulations are employed to reveal three distinctly different flow regions in rotating spherical Rayleigh‐Bénard convection. In the high‐latitude region vertical (parallel to the axis of rotation) convective columns are generated between the hot inner and the cold outer sphere. The mid‐latitude region is dominated by vertically aligned convective columns formed between the Northern and Southern hemispheres of the outer sphere. The diffusion‐free scaling, which indicates bulk‐dominated convection, originates from this mid‐latitude region. In the equator region , the vortices are affected by the outer spherical boundary and are much shorter than in region .
An Observational Constraint on Aviation‐Induced Cirrus From the COVID‐19‐Induced Flight Disruption
Authors: Digby Ruth A. R. , Gillett Nathan P. , Monahan Adam H. , Cole Jason N. S.
Published: September 2021

Global aviation dropped precipitously during the Covid‐19 pandemic, providing an unprecedented opportunity to study aviation‐induced cirrus (AIC). AIC is believed to be responsible for over half of aviation‐related radiative forcing, but until now, its radiative impact has only been estimated from simulations. Here, we show that satellite observations of cirrus cloud do not exhibit a detectable global response to the dramatic aviation reductions of spring 2020. These results indicate that previous model‐based estimates may overestimate AIC. In addition, we find no significant response of diurnal surface air temperature range to the 2020 aviation changes, reinforcing the findings of previous studies. Though aviation influences the climate through multiple pathways, our analysis suggests that its warming effect from cirrus changes may be smaller than previously estimated.
Crustal and Upper Mantle Structure Beneath the Southeastern United States From Joint Inversion of Receiver Functions and Rayleigh Wave Dispersion
Authors: Yang Qiuyue , Liu Kelly H. , Wang Tuo , Song Jianguo , Gao Stephen S.
Published: September 2021

Using data from 186 stations belonging to the USArray Transportable Array, a three‐dimensional shear wave velocity model for the southeastern United States is constructed for the top 180 km by a joint inversion of receiver functions and Rayleigh wave phase velocity dispersion computed from ambient noise and teleseismic earthquake data. The resulting shear wave velocity model and the crustal thickness and Vp/Vs () measurements show a clear spatial correspondence with major surficial geological features. The distinct low velocities observed in the depth range of 0–25 km beneath the eastern Gulf Coastal Plain reflect the thick layer of unconsolidated or poorly consolidated sediments atop the crystalline crust. The low (1.70–1.74) and slow lowermost crustal velocities observed beneath the eastern Southern Appalachian Mountains (including the Carolina Terrane and Inner Piedmont) relative to the adjacent Blue Ridge Mountains and Valley and Ridge can be interpreted by lower crustal delamination followed by relamination. The Osceola intrusive complex in the central Suwannee Terrane has similar crustal characteristics as the eastern Southern Appalachian Mountains and thus can similarly be attributed to crustal delamination/relamination processes. The Grenville Province and adjacent areas possess relatively high values which can be attributed to mafic intrusion associated with crustal extension in a recently recognized segments of the eastern arm of the Proterozoic Midcontinent Rift.
The Kyrenia Terrane (Northern Cyprus): Detrital Zircon Evidence for Exotic Elements in the Southern Neotethys
Authors: Glazer A. , Avigad D. , Morag N. , Güngör T. , Gerdes A.
Published: September 2021

The Kyrenia terrane of northern Cyprus comprises a tectonic stack of Triassic to Eocene rock units interleaved with basic and acid volcanics and minor metamorphic inliers, alongside an Oligocene‐Miocene flysch. Our U‐Pb‐Hf detrital zircon investigation in the Kyrenia Triassic to Eocene section reveals Precambrian, Silurian (∼430 Ma), Carboniferous (∼300 Ma), Triassic (∼240 Ma), and Upper Cretaceous (∼85 Ma) zircons. The presence of 300 Ma zircons, as early as in Triassic sediments, is enigmatic because Carboniferous magmatism is confined to the Paleotethyan realm which is traced north of the Taurides. Deposition of the Kyrenia sequence closer to a Northern Tethyan province would better fit its detrital zircon signal. The detrital signal of the Kyrenia, indicative for derivation from areas north of the Mediterranean, also differs significantly from that of the Mamonia Complex (SW Cyprus) in which only Afro‐Arabian sources are distinguished. Thus, in view of its unusual detrital zircon content, the Kyrenia sequence stands out in the Eastern Mediterranean as an exotic rock pile that cannot be straightforwardly correlated with its neighboring geologic environment. We defined the metamorphic inliers of Kyrenia as an ophiolitic mélange and recognized blueschist‐greenschist facies metamorphism to which we infer an Upper Cretaceous age. A U‐Pb zircon age of 555 ± 9 Ma (Cadomian) was obtained for the crystallization of a metabasic rock in the mélange. These findings support the geodynamic linkage of the Kyrenia with the Alanya and Bitlis massifs that were also affected by Upper Cretaceous HP‐LT metamorphism and accreted to the southern Tauride.