bluuebunny/crossref_metadata_2025 huggingface dataset:
Alginate films augmented with chlorhexidine hexametaphosphate particles provide sustained antimicrobial properties for application in wound care
Authors: Duckworth Peter F. , Maddocks Sarah E. , Rahatekar Sameer S. , Barbour Michele E.
Published: March 2020

All chronic wounds are colonised by bacteria; for some, colonisation progresses to become infection. Alginate wound dressings are used for highly exuding chronic wounds as they are very absorbent, taking up large quantities of exudate while maintaining a moist wound bed to support healing. Some alginate dressings are doped with antimicrobials, most commonly silver, but evidence regarding the efficacy of these is largely inconclusive. This manuscript describes the development and in vitro assessment of alginate materials doped with chlorhexidine hexametaphosphate (CHX-HMP), a sparingly soluble salt which when exposed to aqueous environments provides sustained release of the common antiseptic chlorhexidine. Comparator materials were a commercial silver alginate dressing material and an alginate doped with chlorhexidine digluconate (CHXdg). CHX-HMP alginates provided a dose-dependent CHX release which was sustained for over 14 days, whereas CHXdg alginates released limited CHX and this ceased within 24 h. CHX-HMP and silver alginates were efficacious against 5 major wound pathogens (MRSA,E. coli, P. aeruginosa, K. pneumoniae, A. baumannii) in a total viable count (TVC) and an agar diffusion zone of inhibition (ZOI) model. At baseline the silver alginate was more effective than the CHX-HMP alginate in the TVC assay but the CHX-HMP alginate was the more effective in the ZOI assay. After 7 days’ artificial aging the CHX-HMP alginate was more effective than the silver alginate for four of the five bacteria tested in both assays. These materials may ultimately find application in the development of wound dressings for chronic wounds that provide sustained antimicrobial protection.
Fuel for Thought? A Systematic Review of Neuroimaging Studies into Glucose Enhancement of Cognitive Performance
Authors: Peters Riccarda , White David , Cleeland Carlee , Scholey Andrew
Published: March 2020

A transient improvement in cognitive performance can be observed following the ingestion of a glucose drink, a phenomenon known as the ‘glucose facilitation effect’. The effect has been studied thoroughly in the last three decades, but its neural underpinnings remain a matter of speculation. A systematic review was conducted to evaluate the current evidence from studies applying neuroimaging or neurophysiological methods to investigate the glucose enhancement effect. Eleven studies met the inclusion criteria of using neuroimaging in conjunction with cognitive outcomes. Six studies employed electroencephalography (EEG), four used functional magnetic resonance imaging (fMRI) and one employed functional near-infrared spectroscopy (fNIRS). All but one study reported modulation of neurophysiology or neuroimaging markers following glucose, while only five studies reported significant changes in cognitive outcomes. The evidence suggests that glucose administration enhances neurocognitive markers of episodic memory and attentional processes underpinned by medial temporal and frontal activation, sometimes in the absence of measurable behavioural effects. Further exploration of glucose facilitation using neuroimaging measures with increased sample sizes is warranted to replicate these findings.
Cubic quintic Ginzburg Landau equation as a model for resonant interaction of EM field with nonlinear media
Authors: Aleksić Branislav N. , Uvarova Liudmila A. , Aleksić Najdan B. , Belić Milivoj R.
Published: March 2020

In this work, we investigate the possibility of approximating saturable nonlinearity, which is commonly used in complex Ginzburg–Landau equation (CGLE) for modelling resonant interaction of an electromagnetic field with nonlinear media, with cubic-quintic (CQ) nonlinearity. To validate the suggested approximations, we use variational method to estimate 2D analytical solutions of the CGLE with both saturable and CQ nonlinearity. The paper compares three ways to determine parameters of the CQ approximation and discusses the obtained results in terms of accuracy.
Strain-specificity in the hydrogen sulphide signalling network following dietary restriction in recombinant inbred mice
Authors: Wilkie Stephen E. , Mulvey Lorna , Sands William A. , Marcu Diana E. , Carter Roderick N. , Morton Nicholas M. , Hine Christopher , Mitchell James R. , Selman Colin
Published: March 2020

Modulation of the ageing process by dietary restriction (DR) across multiple taxa is well established. While the exact mechanism through which DR acts remains elusive, the gasotransmitter hydrogen sulphide (H2S) may play an important role. We employed a comparative-type approach using females from three ILSXISS recombinant inbred mouse strains previously reported to show differential lifespan responses following 40% DR. Following long-term (10 months) 40% DR, strain TejJ89—reported to show lifespan extension under DR—exhibited elevated hepatic H2S production relative to its strain-specific ad libitum (AL) control. Strain TejJ48 (no reported lifespan effect following 40% DR) exhibited significantly reduced hepatic H2S production, while H2S production was unaffected by DR in strain TejJ114 (shortened lifespan reported following 40% DR). These differences in H2S production were reflected in highly divergent gene and protein expression profiles of the major H2S production and disposal enzymes across strains. Increased hepatic H2S production in TejJ89 mice was associated with elevation of the mitochondrial H2S-producing enzyme 3-mercaptopyruvate sulfurtransferase (MPST). Our findings further support the potential role of H2S in DR-induced longevity and indicate the presence of genotypic-specificity in the production and disposal of hepatic H2S in response to 40% DR in mice.
Wire Laser Arc Additive Manufacture of aluminium zinc alloys
Authors: Eimer E. , Suder W. , Williams S. , Ding J.
Published: March 2020

Aluminium zinc alloys are widely used in the aerospace industry due to their high strength. However, only a few studies have been reported on the additive manufacture of aluminium zinc alloys. This rarity is due to the difficulties occurring during the fusion processing of these alloys and to the lack of available raw material. This paper presents an alternative process used for the deposition of aluminium zinc alloys. In this study, a Wire Laser Arc Additive Manufacture (WLAAM) system was used. This consisted of a gas metal arc power source, used to generate the melt pool, and a laser beam applied to control the melt pool size. By using this approach, it was possible to produce an elongated melt pool and feed zinc into it with a cold wire without compromising the process stability. A welding camera along with a system measuring the arc voltage and current was used to monitor the process. Different process parameters and configurations were investigated along with their effect on process stability and deposited material microstructure. A very high zinc concentration was achieved in the deposited material without macro-segregation.
Schülervorstellungen in einem inquiry-orientierten Sachunterricht verändern – Besteht ein Zusammenhang mit der Förderung adäquaten Schlussfolgerns?
Authors: Grimm Hanna , Todorova Maria , Möller Kornelia
Published: March 2020

Die Fähigkeit des hypothesenbezogenen Schlussfolgerns wird in der aktuellen Forschung als ein relevanter Faktor behandelt, der im Rahmen der Hypothesenprüfung im inquiry-orientierten Unterricht zur Erkennung von diskrepanten Ereignissen beiträgt und somit einen kognitiven Konflikt beim Lernenden begünstigen kann. Die Unzufriedenheit eines Lernenden mit den eigenen alternativen Vorstellungen gilt als förderlich für deren Abschwächung und für den Aufbau des wissenschaftlich adäquaten Konzepts. Der Zusammenhang zwischen dem hypothesenbezogenen Schlussfolgern und alternativen Vorstellungen ist bislang kaum untersucht worden. In der vorliegenden Interventionsstudie wurde ein inquiry-orientierter Unterricht zum Thema „Wie kommt es, dass ein Ball springt?“ durchgeführt (N = 143 Drittklässler/innen). Während in einer Kontrollgruppe ein Unterricht zur Unterstützung von Schülervorstellungsveränderungen stattfand, erhielt eine Experimentalgruppe denselben Unterricht mit zusätzlicher Förderung des hypothesenbezogenen Schlussfolgerns. In einem Prä-Post-Follow-Up-Design wurden sowohl das hypothesenbezogene Schlussfolgern als auch die alternativen Vorstellungen zum Sprungverhalten von Gegenständen erfasst, um die Veränderung der alternativen Vorstellungen über die Zeit und den Zusammenhang zwischen dem hypothesenbezogenen Schlussfolgern und alternativen Vorstellungen mithilfe von Mehrebenenanalysen zu untersuchen. Zudem wurde überprüft, inwiefern sich die zusätzliche Förderung des hypothesenbezogenen Schlussfolgerns in der Experimentalgruppe auf den Entwicklungsverlauf der alternativen Vorstellungen auswirkt. Die Ergebnisse zeigen für die Gesamtkohorte eine signifikante hypothesenkonforme Abschwächung alternativer Vorstellungen nach dem Unterricht und eine erneute geringfügige Zunahme dieser nach einigen Monaten. Zudem geht eine höhere Ausprägung der Fähigkeit, widerlegende und irrelevante Ereignisse bei der Überprüfung von konditionalen Aussagen adäquat zu evaluieren, mit einer signifikant geringeren Zustimmung zu alternativen Vorstellungen einher. Darüber hinaus liegt eine signifikante Cross-Level-Interaktion zwischen der Interventionsgruppe und dem Entwicklungsverlauf der alternativen Vorstellungen zugunsten der Experimentalgruppe vor. Die Ergebnisse deuten darauf hin, dass die Schlussfolgerungsfähigkeit und deren Förderung im naturwissenschaftlichen Unterricht einen positiven Einfluss auf die Veränderung von alternativen Vorstellungen haben kann.
Multi-model synthesis of future extreme temperature indices over Zambia
Authors: Libanda Brigadier
Published: March 2020

Although temperature is one of the most important climate variables to be considered in adapting systems to climate change, its study over Zambia has until recently been largely ignored. A dearth of the literature on future temperature extremes is especially apparent. For the first time, future extreme temperature variability is analysed in Zambia for the period 1961–2100. The nonparametric Mann–Kendall test statistic is used at 5% significant level to compute trends. Sen’s slope estimator is used to give the magnitude of the observed trends. A two-tailed Kolmogorov–Smirnov statistical test is used to calculate the significance of the observed changes. What stands out from the findings is that warm days and nights become warmer while cool days and nights are projected to become non-existent by 2100. Additionally, an increase in radiative forcing and time is seen to intensify extreme temperature events. Notably, much of southern Zambia is projected to experience ~ 30% increment in TX90p while the northern half will experience ~ 40% under RCP4.5 by the middle of the century (2021–2050). If the business-as-usual trajectory (RCP8.5) is followed, an intensification of TX90p is observed with ~ 40% in the southern half of the country and ~ 50% in the northern half. These projections are observed to almost double towards the end of the century (2071–2100). The projected increase in warm nights (TN90p) is more over Luapula and Northwestern province while the lowest is observed over the Livingstone/Magoye region. These results provide a foundation for strategic planning purposes to avert losses related to extreme temperature.
Using correlated stochastic differential equations to forecast cryptocurrency rates and social media activities
Authors: Dipple Stephen , Choudhary Abhishek , Flamino James , Szymanski Boleslaw K. , Korniss G.
Published: March 2020

The growing interconnectivity of socio-economic systems requires one to treat multiple relevant social and economic variables simultaneously as parts of a strongly interacting complex system. Here, we analyze and exploit correlations between the price fluctuations of selected cryptocurrencies and social media activities, and develop a predictive framework using noise-correlated stochastic differential equations. We employ the standard Geometric Brownian Motion to model cryptocurrency rates, while for social media activities and trading volume of cryptocurrencies we use the Geometric Ornstein-Uhlenbeck process. In our model, correlations between the different stochastic variables are introduced through the noise in the respective stochastic differential equation. Using a Maximum Likelihood Estimation on historical data of the corresponding cryptocurrencies and social media activities we estimate parameters, and using the observed correlations, forecast selected time series. We successfully analyze and predict cryptocurrency related social media and the cryptocurrency market itself with a reasonable degree of accuracy. In particular, we show that our method has impressive accuracy in predicting whether a cryptocurrency market will increase or decrease a day in the future, a significant result with regards to investing and trading cryptocurrencies.
Alles Wut? Der Einfluss von Emotionen auf die Wahrnehmung und Wirkung von TV-Debatten am Beispiel der Bundestagswahl 2017
Authors: Waldvogel Thomas
Published: March 2020

Lange Zeit dominierten kognitive Zugänge die politik- und kommunikationswissenschaftliche Debattenforschung in Deutschland. Wir argumentieren in diesem Beitrag, dass Rezipienten eine Fernsehdebatte nicht nur durch ihre eigene parteipolitische Brille selektiv wahrnehmen, sondern deren emotionalen Zustände die Verarbeitung politischer Informationen, die Wahrnehmungsprozesse aber auch die politische Urteils- und Einstellungsbildung maßgeblich beeinflussen. Auf Basis von Echtzeit- und Umfragedaten von 1191 Studienteilnehmern im Rahmen einer Feldstudie zu einer TV-Debatte der Bundestagswahl 2017 zeigen wir, dass die Kandidaten unterschiedliche Emotionen unter den Rezipienten evozieren, welche sich entlang von Parteibindungen strukturieren. Zweitens wird deutlich, dass stark ausgeprägte Emotionen sowohl in der zeitlichen Dynamik als auch interindividuell zu signifikant unterschiedlichen Wahrnehmungen führen und gleichzeitig die Homogenität innerhalb emotionaler Teilgruppen erhöhen können. Dabei hat die Valenz, verstanden als Differenzierung zwischen positiven und negativen Emotionen, einen entscheidenden Einfluss auf die Echtzeitbewertungen der Kandidaten. Drittens zeigen wir, dass Emotionen die strukturellen Wirkmechanismen der Debattenrezeption auf nachgelagerte Einstellungen wie die Urteile über die Debattenleistung und die Kandidatenevaluation systematisch beeinflussen. Insgesamt finden wir empirische Evidenz dafür, dass ein einfaches duales Prozess-Modell über die Wirkung von Emotionen, welches deren Valenz in den Mittelpunkt stellt und auf einem bipolaren Kontinuum abbildet, eine hohe Konformität mit unseren Daten aufweist.
Designing the Swedish Crime Harm Index: an Evidence-Based Strategy
Authors: Kärrholm Fredrik , Neyroud Peter , Smaaland John
Published: March 2020

Research Question

Which method for deriving a Crime Harm Index (Policing 10:171–183, 2016) for Sweden from criminal justice sources offers the best evidence for providing a sensitive indicator of differences in harm levels across offence categories?

Data

The number of days of imprisonment for each offence category associated with five different kinds of scales were extracted and compared: consensus by an expert panel of judges, the statutory maximum penalties, statutory minimum penalties, the average of maximum and minimum penalties and the average of actual sentences imposed in a recent time period for each crime type. Unlike the UK, for which the Cambridge Crime Harm Index draws on sentencing guidelines, Sweden has no such guidelines to offer.

Methods

The data were compared for sensitivity defined as the difference in length of imprisonment days between high and low severity crimes, as well as other characteristics of the data sources.

Findings

Given the available alternatives, the sentencing data average of actual sentences handed down by crime type provided the greatest reliability and sensitivity across the penalties for offences of high and low severity. Applying that method to both crime trends and crime mapping produces substantially different results from counting all crimes with equal weight and can be used by police and others to allocate resources with greater precision in relation to harm prevention.

Conclusions

On both empirical and normative grounds, the average sentences in a recent time period for each crime category provides the most sensitive and democratic method for establishing an officially recognized Swedish Crime Harm Index.
Review of supercritical carbon dioxide (sCO2) technologies for high-grade waste heat to power conversion
Authors: Marchionni Matteo , Bianchi Giuseppe , Tassou Savvas A.
Published: March 2020

In the European Industry, 275 TWh of thermal energy is rejected into the environment at temperatures beyond 300 °C. To recover some of this wasted energy, bottoming thermodynamic cycles using supercritical carbon dioxide (sCO2) as working fluid are a promising technology for the conversion of the waste heat into power. CO2 is a non-flammable and thermally stable compound, and due to its favourable thermo-physical properties in the supercritical state, can lead to high cycle efficiencies and a substantial reduction in size compared to alternative heat to power conversion technologies. In this work, a brief overview of the sCO2 power cycle technology is presented. The main concepts behind this technology are highlighted, including key technological challenges with the major components such as turbomachinery and heat exchangers. The discussion focuses on heat to power conversion applications and benefits of the experience gained from the design and construction of a 50 kWe sCO2 test facility at Brunel University London. A comparison between sCO2 power cycles and conventional heat to power conversion systems is also provided. In particular, the operating ranges of sCO2 and other heat to power systems are reported as a function of the waste heat source temperature and available thermal power. The resulting map provides insights for the preliminary selection of the most suitable heat to power conversion technology for a given industrial waste heat stream.
Deep Open Set Recognition Using Dynamic Intra-class Splitting
Authors: Schlachter Patrick , Liao Yiwen , Yang Bin
Published: March 2020

This paper provides a generic deep learning method to solve open set recognition problems. In open set recognition, only samples of a limited number of known classes are given for training. During inference, an open set recognizer must not only correctly classify samples from known classes, but also reject samples from unknown classes. Due to these specific requirements, conventional deep learning models that assume a closed set environment cannot be used. Therefore, special open set approaches were taken, including variants of support vector machines and generation-based state-of-the-art methods which model unknown classes by generated samples. In contrast, our proposed method models unknown classes by atypical subsets of training samples. The subsets are obtained through intra-class splitting (ICS). Based on a recently proposed two-stage algorithm using ICS, we propose a one-stage method based on alternating between ICS and the training of a deep neural network. Finally, several experiments were conducted to compare our proposed method with conventional and other state-of-the-art methods. The proposed method based on dynamic ICS showed a comparable or better performance than all considered existing methods regarding balanced accuracy.
Gender and the future of macroeconomics: an evolutionary approach
Authors: Dow Sheila
Published: March 2020

Gender lends itself well to an evolutionary analysis which focuses on non-equilibrium change and transformation for individuals within society. Decomposition by such an important category as gender helps us understand the economy at the macro level, and design macroeconomic policy, better. It also provides the foundation for advocating equal gender rights and outcomes. But, where gendered policy issues arise in mainstream macroeconomics (income maldistribution, labour market composition, etc.), the subject matter is narrowed by its microfoundations, by focusing on GDP growth and on suboptimal outcomes being explained by market imperfections. An approach which takes gender seriously requires the different epistemology which arises from feminism: it does not rely on dualistic categorisations, but builds on the idea of situated knowledge, which in turn requires a pluralist methodology and an acceptance of fundamental uncertainty. Such a methodology allows for emergent identity, for the cognitive roles of emotion and social convention, and for attention to power other than market power. Reflecting on how limited is the scope for mainstream macroeconomics to address gender, and what is required of a useful alternative, a political economy approach provides a clear focus for a more general discussion of the future of macroeconomics from an evolutionary perspective.
The Disease Ecology, Epidemiology, Clinical Manifestations, and Management of Trichinellosis Linked to Consumption of Wild Animal Meat
Authors: Diaz James H. , Warren Rebecca J. , Oster Marissa J.
Published: March 2020

Historically, human trichinellosis was caused by Trichinella spiralis and transmitted to humans by consumption of undercooked domestic pork. Today, most cases of trichinellosis are caused by other Trichinella species and transmitted by consumption of raw or undercooked wild game meats. Given the increasing global prevalence of wild animal meat-linked trichinellosis, the objectives of this review are: 1) to describe the life cycle and global distribution of Trichinella worms; 2) to describe the changing epidemiology of trichinellosis; 3) to describe the clinical phases of trichinellosis; 4) to recommend the latest diagnostic tests; and 5) to recommend treatment and prevention strategies. Internet search engines were queried with keywords as subject headings to meet the objectives of this review. Although trichinellosis surveillance systems and laws regulating commercial pork production have limited T spiralis-caused trichinellosis in Europe and the United States, trichinellosis due to consumption of raw and undercooked wild boar and feral hog meat continues to occur throughout Southeast Asia. Trichinellosis due to consumption of raw or undercooked meats of other infected game, such as bear, deer, moose, and walrus, continues to occur worldwide. Only adherence to hygienic practices when preparing wild game meats and cooking wild game meats to recommended internal temperatures can prevent transmission of trichinellosis to humans. Wilderness medicine clinicians should be prepared to advise hunters and the public on the risks of game meat-linked trichinellosis and on how to diagnose and treat trichinellosis to prevent fatal complications.
LOCAL DUALITY FOR THE SINGULARITY CATEGORY OF A FINITE DIMENSIONAL GORENSTEIN ALGEBRA
Authors: BENSON DAVE , IYENGAR SRIKANTH B. , KRAUSE HENNING , PEVTSOVA JULIA
Published: March 2020

A duality theorem for the singularity category of a finite dimensional Gorenstein algebra is proved. It complements a duality on the category of perfect complexes, discovered by Happel. One of its consequences is an analogue of Serre duality, and the existence of Auslander–Reiten triangles for the$\mathfrak{p}$-local and$\mathfrak{p}$-torsion subcategories of the derived category, for each homogeneous prime ideal$\mathfrak{p}$arising from the action of a commutative ring via Hochschild cohomology.
On approximating minimizers of convex functionals with a convexity constraint by singular Abreu equations without uniform convexity
Authors: Le Nam Q.
Published: March 2020

We revisit the problem of approximating minimizers of certain convex functionals subject to a convexity constraint by solutions of fourth order equations of Abreu type. This approximation problem was studied in previous articles of Carlier–Radice (Approximation of variational problems with a convexity constraint by PDEs of Abreu type. Calc. Var. Partial Differential Equations58 (2019), no. 5, Art. 170) and the author (Singular Abreu equations and minimizers of convex functionals with a convexity constraint, arXiv:1811.02355v3, Comm. Pure Appl. Math., to appear), under the uniform convexity of both the Lagrangian and constraint barrier. By introducing a new approximating scheme, we completely remove the uniform convexity of both the Lagrangian and constraint barrier. Our analysis is applicable to variational problems motivated by the original 2D Rochet–Choné model in the monopolist's problem in Economics, and variational problems arising in the analysis of wrinkling patterns in floating elastic shells in Elasticity.
Remembering Africanization: two conversations among elderly science workers about the perpetually promissory
Authors: Geissler P. Wenzel , Gerrets René , Kelly Ann H. , Mangesho Peter , Poleykett Branwyn , Okwaro Ferdinand Moyi
Published: March 2020

The ‘Africanization’ of science after decolonization was replete with dreams. Claims to Africa's place in the high-modern world, expectations of national technological and economic progress, and individual dreams of scientific discovery, professional development and fulfilled careers drove scientific work and lives. The term Africanization, coined by the colonizers, reproduced colonial notions of race but also stimulated the imagination of mid-twentieth-century African scientists, who hotly debated and enthusiastically embraced it. Half a century later, some dreams have failed, but many more remain unfulfilled. This article examines two reunions of Tanzanian and European science workers – in Amani in 2015 and in Cambridge in 2013 – who had worked together in the decades after Tanzania's independence at Amani Hill Research Station, then one of Africa's foremost laboratories for research on malaria and other tropical diseases. It explores ideas of good science and experiences of social differentiation, divergent dreams and persistent tensions – and the role of joking in remembering these.
Remembering Africanization: excerpt of reunion transcripts
Authors: Geissler P. Wenzel
Published: March 2020

Professor Bukheti Swalehe Kilonzo, born 1949: joined Amani in 1968 as a Scientific Assistant. Studied microbiology and parasitology in London; PhD in plague epidemiology from Dar es Salaam in 1984. Left Amani in 1982 as Research Scientist and became professor at Sokoine University.
From Russia with love: medical modernities, development dreams, and Cold War legacies in Kenya, 1969 and 2015
Authors: Prince Ruth J.
Published: March 2020

In 1966, a new hospital was being built in western Kenya with Soviet aid. Designed by Soviet architects and planners, with equipment transported from the USSR, it was to be the largest hospital in Kenya. Still referred to today by Kenyans as ‘Russia’, it was the pet project of Oginga Odinga, the central figure of political opposition in postcolonial Kenya, who cultivated friendship with the USSR. Like the training offered to African students at the Patrice Lumumba University in Moscow, the hospital was a gift of the Soviets, a material embodiment of medical modernity, socialist internationalism and Africa's hopeful future. However, it soon became deeply embroiled in Kenya's Cold War politics. This article explores the remains and legacies of these Soviet gifts, tracing their connections to visions of progress and development, decolonization and struggles for political freedom in postcolonial Kenya. Drawing on ethnographic fieldwork, archival material, newspaper reports and interviews with Kenyans who were educated in the Soviet Union, I trace how, in institutional, bureaucratic, affective and biographical remains, diverging dreams and anticipations of progress and development converged and collided. Russia, like the city of which it forms a part, emerges as a palimpsest: a site of hopes and dreams, violence and disappointment, and the anticipation of futures.
Plasma expansion towards an electrically insulated surface
Authors: Rhodes Dov J. , Farrell William M.
Published: March 2020

The problem of plasma expansion into a vacuum is revisited with the addition of a finite boundary condition; an electrically insulated surface. As plasma expands towards a charge-accumulating surface, the leading electron cloud charges the surface negatively, which in turn repels electrons and attracts ions. This plasma–surface interaction is shown to result in a feedback process which accelerates the plasma expansion. In addition, we examine the decrease in (negative) surface potential and associated near-surface electron density. To investigate this plasma coupling with an electrically floating surface, we develop an analytic model including four neighbouring plasma regions: (i) undisturbed plasma, (ii) quasi-neutral self-similar expansion, (iii) ion front boundary layer and (iv) electron cloud. A key innovation in our approach is a self-contained analytic approximation of the ion front boundary layer, providing a spatially continuous electric field model for the early phase of bounded plasma expansion.
Optimal, resource-rational or sub-optimal? Insights from cognitive development
Authors: Bejjanki Vikranth R. , Aslin Richard N.
Published: March 2020

We agree with the authors regarding the utility of viewing cognition as resulting from an optimal use of limited resources. Here, we advocate for extending this approach to the study of cognitive development, which we feel provides particularly powerful insight into the debate between bounded optimality and true sub-optimality, precisely because young children have limited computational and cognitive resources.
Computational limits don't fully explain human cognitive limitations
Authors: Davis Ernest S. , Marcus Gary F.
Published: March 2020

The project of justifying all the limits and failings of human cognition as inevitable consequences of strategies that are actually “optimal” relative to the limits on computational resources available may have some value, but it is far from a complete explanation. It is inconsistent with both common observation and a large body of experimentation, and it is of limited use in explaining human cognition.
Multiple conceptions of resource rationality
Authors: Ma Wei Ji , Woodford Michael
Published: March 2020

Resource rationality holds great promise as a unifying principle across theories in neuroscience, cognitive science, and economics. The target article clearly lays out this potential for unification. However, resource-rational models are more diverse and less easily unified than might appear from the target article. Here, we explore some of that diversity.
I Feel Your Pain: Embodied Knowledges and Situated Neurons
Authors: Pitts‐Taylor Victoria
Published: March 2020

The widely touted discovery of mirror neurons has generated intense scientific interest in the neurobiology of intersubjectivity. Social neuroscientists have claimed that mirror neurons, located in brain regions associated with motor action, facial recognition, and somatosensory processing, allow us to automatically grasp other people's intentions and emotions. Despite controversies, mirror neuron research is animating materialist, affective, and embodied accounts of intersubjectivity. My view is that mirror neurons raise issues that are directly relevant to feminism and cultural studies, but interventions are needed for the work to be compatible with nonreductionist critical thought. In this article I critique the dominant neuroscientific account of mirror neurons, called embodied simulation theory. I draw from feminist epistemologies as well as alternative interpretations of mirror neurons in cognitive science and philosophy of mind to consider mirroring as situated, embodied perception.
Morphokinetics and in vitro developmental potential of monopronucleated ICSI zygotes until the blastocyst stage
Authors: Mateo Silvia , Vidal Francesca , Carrasco Beatriz , Rodríguez Ignacio , Coroleu Buenaventura , Veiga Anna , Boada Montserrat
Published: March 2020

The aim of this study was to provide a more comprehensive understanding of 1PN intracytoplasmic sperm injection (ICSI) zygotes. To achieve this objective, we assessed whether all 1PN-derived embryos showed a similar morphokinetic pattern, and if the morphokinetic behaviour of 1PN-derived embryos was comparable with that of 2PN-derived embryos. In total, 149 1PN ICSI zygotes (study group) and 195 2PN ICSI zygotes (control group) were included in the study. Embryo development potential was evaluated in terms of blastocyst rate. Morphokinetic parameters, including the pronucleus diameter and kinetics of in vitro development, were also analyzed. Embryos derived from 1PN ICSI zygotes showed impaired development compared with 2PN-derived embryos, with blastocyst rates of 28.9% and 67.2%, respectively. The diameter of the pronucleus of 1PN zygotes was larger than that of 2PN zygotes. When compared with 2PN-derived embryos, those derived from 1PN zygotes had a visible pronucleus for a shorter time, in addition to a longer syngamy time and slower kinetic behaviour from two to nine cells. When 1PN-derived blastocysts and 2PN-derived blastocysts were compared, the developmental kinetics were similar in both groups, except for a delayed and longer duration of the compaction phase in 1PN-derived embryos. In conclusion, monopronucleated ICSI zygotes present differences in developmental capacity and morphokinetic behaviour compared with 2PN ICSI zygotes, showing particular morphokinetic parameters related to pronucleus formation. Only the 1PN ICSI-derived embryos that reached the blastocyst stage have similar morphokinetic development to blastocysts from 2PN zygotes.
Stellar rotation bifurcation caused by tidal locking in the open cluster NGC 2287?
Authors: Sun Weijia , Li Chengyuan , Deng Licai , de Grijs Richard
Published: March 2020

We present a detailed analysis of the projected stellar rotational velocities of the well-separated double main sequence (MS) in the young, ∼200 Myr-old Milky Way open cluster NGC 2287 and suggest that stellar rotation may drive the split MSs in NGC 2287. We find that the observed distribution of projected stellar rotation velocities could result from a dichotomous distribution of stellar rotation rates. We discuss whether our observations may reflect the effects of tidal locking affecting a fraction of the cluster’s member stars in stellar binary systems. The slow rotators are likely stars that initially rotated rapidly but subsequently slowed down through tidal locking induced by low-mass-ratio binary systems. However, the cluster may have a much larger population of short-period binaries than is usually seen in the literature, with relatively low secondary masses.
The role of cluster age on the onset of multiple populations in stellar clusters
Authors: Martocchia S.
Published: March 2020

The origin of the chemical anomalies in star clusters is still an open question, although much effort has been employed both from a theoretical and observational point of view. The exploration of the dependence of such multiple stellar populations based on certain cluster properties (e.g. mass, age, metallicity) has represented a compelling line of investigation so far. Here I report an overview of the results obtained from our latest surveys aimed at characterising the phenomenon of chemical variations in star clusters that are much younger with respect to the ancient globular clusters. The fundamental question we are asking is whether these abundance patterns are only restricted to the old massive clusters; and if not, is there a difference between young and old objects?
Black Hole dynamics in Young Star Clusters
Authors: Rastello Sara , di Carlo Ugo N. , Mapelli Michela , Giacobbo Nicola , Ballone Alessandro
Published: March 2020

Young star clusters are a promising environment for forming binary black holes. Such binaries may form dynamically or via binary star evolution or through the interplay of these two channels. To study these formation pathways, we have performed high precision direct N-body simulations of low-mass (M < 1000 M⊙) young star clusters. The simulations were carried out with the code Nbody6++GPU coupled with the population synthesis code MOBSE. Our results highlight the importance of dynamics to form massive black hole binaries even in low-mass young star clusters.
Using MUSE-AO observations to constrain the formation of the large nuclear star cluster in FCC 47
Authors: Fahrion Katja , Lyubenova Mariya , van de Ven Glenn , Hilker Michael
Published: March 2020

Nuclear star clusters (NSCs) are found in at least 70% of all galaxies, but their formation path is still unclear. In the most common scenarios, NSCs form in-situ from the galaxy’s central gas reservoir, through merging of globular clusters (GCs), or through a combination of the two. As the scenarios pose different expectations for angular momentum and stellar population properties of the NSC in comparison to the host galaxy and the GC system, it is necessary to characterise the stellar light, NSC, and GCs simultaneously. Wide-field observations with modern integral field units such as the Multi Unit Spectroscopic Explorer (MUSE) allow to perform such studies. However, at large distances, NSCs usually are not resolved in MUSE observations. The particularly large NSC (Reff ∼ 66 pc) of the early-type galaxy FCC 47 at distance of ∼20 Mpc is an exception and is therefore an ideal laboratory to constrain NSC formation of external galaxies.
Simulating star-forming regions in spiral galaxies with AMUSE
Authors: Rieder Steven , Dobbs Clare , Bending Thomas
Published: March 2020

We present a model for hydrodynamic + N-body simulations of star cluster formation and evolution using AMUSE. Our model includes gas dynamics, star formation in regions of dense gas, stellar evolution and a galactic tidal spiral potential, thus incorporating most of the processes that play a role in the evolution of star clusters.

We test our model on initial conditions of two colliding molecular clouds as well as a section of a spiral arm from a previous galaxy simulation.
Evolution and origin of Blue Stragglers in 47 Tucanae
Authors: Parada Javiera , Richer Harvey , Heyl Jeremy , Kalirai Jason , Goldsbury Ryan
Published: March 2020

Using data from the core of 47 Tuc we have identified stars in different evolutionary stages in the colour-magnitude diagram, and used the effects of mass segregation on their radial distribution to study the evolution and origin of blue stragglers (BSS). We separate the BSS into 2 samples by their magnitude and find considerable differences in their distribution. Bright BSS are more centrally concentrated with mass estimates over twice the turn-off mass suggesting an origin involving a triple or multiple star system. The distribution of the faint BSS is close to that of the main-sequence (MS) binaries pointing to these stars as their likely progenitors. Using MESA models, we calculate the expected number of stars in each evolutionary stage and compare it with the observed number of stars. Results indicate that BSS have a post-MS evolution comparable to that of a normal star of the same mass and a MS-BSS lifetime of about 200 – 300 Myr.
The origin of metal-poor and metal-rich globular clusters in E-MOSAICS
Authors: Reina-Campos Marta
Published: March 2020

It has been a long-standing open question why observed globular cluster (GC) populations of different metallicities differ in their ages and spatial distributions, with metal-poor GCs being the older and radially more extended of the two. We use the suite of 25 Milky Way-mass cosmological zoom-in simulations from the E-MOSAICS project, which self-consistently model the formation and evolution of stellar clusters and their host galaxies, to understand the properties of observed GC populations. We find that the different ages and spatial distributions of metal-poor and metal-rich GCs are the result of regular cluster formation at high redshift in the context of hierarchical galaxy assembly. We also find that metallicity on its own is not a good tracer of accretion, and other properties, such as kinematics, need to be considered.
Spectroscopy of LMC cluster stars
Authors: Dupree A. K. , Johnson C. I. , Mateo M. , Milone A. P.
Published: March 2020

High resolution spectra of stars in the ≈200 Myr LMC globular cluster, NGC 1866, reveal rapidly rotating stars with variable H α emission and absorption, and signatures of outflowing material. The variable H α line can substantially affect photometric measurements obtained with HST/WFC3 narrow-band filters.
Inter-cluster velocity structures of star cluster complexes
Authors: Fujii Michiko S.
Published: March 2020

Star clusters are often born as star-cluster systems, which include several stellar clumps. Such star-cluster complexes could have formed from turbulent molecular clouds. Since Gaia Data Release 2 provided us high quality velocity data of individual stars in known star-cluster complexes, we now can compare the velocity structures of the observed star-cluster complexes with simulated ones. We performed a series of N-body simulations for the formation of star-cluster complexes starting from turbulent molecular clouds. We measured the inter-cluster velocity dispersions of our simulated star-cluster complexes and compared them with the Carina region and NGC 2264. We found that the Carina region and NGC 2264 formed from molecular clouds with a mass of ∼4 × 105M⊙ and ∼4 × 104M⊙, respectively. In our simulations, we also found that the maximum cluster mass (Mc,max) in the complex follows ${M_{{\rm{c}},{\rm{max}}}} = 0.{\rm{2}}0M_g^{0.76}$, where Mg is the initial gas mass.
Globular clusters in the Fornax cluster: A report from the FDS survey
Authors: Cantiello Michele , Venhola A. , Paolillo M. , D’Abrusco R. , Grado A. , Iodice E. , Peletier R. , Capaccioli M. , Hilker M. , Mieske S. , Napolitano N. , Riccio G. , Spavone M. , Quintini M.
Published: March 2020

The Fornax Deep Survey (FDS) is a multi-band imaging survey of the Fornax cluster of galaxies, executed with the ESO VLT Survey Telescope (VST). The survey is designed to reach unprecedented surface brightness and point-source magnitude depth over one virial radius of the cluster. The scientific objectives of the survey are numerous: the study of the galaxy luminosity function, derivation of galaxy scaling relations, determination of the properties of compact stellar systems, an accurate determination of distances and 3-D geometry of the Fornax cluster, analysis of diffuse stellar light and galaxy interactions, etc.

In this contribute we give an overview on the interest of the survey on globular clusters (GC) populations, and present a report the status of the study of GCs also providing some preliminary results of our analysis, with particular regard to the two-dimensional distribution of GC candidates over ∼20 sq. degree area of Fornax centered on NGC 1399.
Dynamical effects on the stellar mass function of multiple stellar populations in globular clusters
Authors: Vesperini Enrico , Hong Jongsuk , Webb Jeremy J. , D’Antona Franca , D’Ercole Annibale
Published: March 2020

We present a brief summary of the results of a study of the effects of dynamical evolution on the stellar mass function of multiple-population globular clusters. Theoretical studies have predicted that the process of multiple-population cluster formation results in a system in which second-generation (2G) stars are initially more centrally concentrated than first-generation (1G) stars. In the study presented here, we have explored the implications of the initial differences between the 2G and 1G structural properties for the evolution of the local (measured at different distances from a cluster center) and global mass function. We have studied both systems in which 1G and 2G stars start with the same initial mass function (IMF) and systems in which 1G and 2G stars have different IMFs. Finally we have explored the evolution of the spatial mixing and found that the multiscale nature of the clusters studied leads to a dependence of the mixing rate on the stellar mass.
On the presence of intermediate black holes in three globular clusters
Authors: Baumgardt Holger , Sollima Antonio , Hilker Michael
Published: March 2020

We investigate whether the globular clusters 47 Tuc, ω Cen and NGC 6624 contain intermediate-mass black holes (IMBHs) by fitting a large grid of N-body simulations against their surface density and velocity dispersion profiles. In our simulations we vary the initial cluster size, the initial mass function and the initial density profile of the clusters as well as the mass fraction of a central intermediate-mass black hole. We find that the surface density and velocity dispersion profiles of all three clusters can be better reproduced by models that do not contain a central IMBH than by any of our IMBH models. If ω Cen and NGC 6624 contain any IMBHs at all, they have to be significantly less massive than suggested in the past.
The systematically varying stellar IMF
Authors: Kroupa Pavel
Published: March 2020

Some ultra-compact dwarf galaxies have large dynamical mass to light (M / L) ratios and also appear to contain an overabundance of LMXB sources, and some Milky Way globular clusters have a low concentration and appear to have a deficit of low-mass stars. These observations can be explained if the stellar IMF becomes increasingly top-heavy with decreasing metallicity and increasing gas density of the forming object. The thus constrained stellar IMF then accounts for the observed trend of metallicity and M / L ratio found amongst M31 globular star clusters. It also accounts for the overall shift of the observationally deduced galaxy-wide IMF from top-light to top-heavy with increasing star formation rate amongst galaxies. If the IMF varies similarly to deduced here, then extremely young very massive star-burst clusters observed at a high redshift would appear quasar-like (Jerabkova et al. 2017).
Chemical abundances of field halo stars - Implications for the building blocks of the Milky Way
Authors: Ishigaki Miho N.
Published: March 2020

I would like to review recent efforts of detailed chemical abundance measurements for field Milky Way halo stars. Thanks to the advent of wide-field spectroscopic surveys up to a several kpc from the Sun, large samples of field halo stars with detailed chemical measurements are continuously expanding. Combination of the chemical information and full six dimensional phase-space information is now recognized as a powerful tool to identify cosmological accretion events that have built a sizable fraction of the present-day stellar halo. Future observational prospects with wide-field spectroscopic surveys and theoretical prospects with supernova nucleosynthetic yields are also discussed.