bluuebunny/crossref_metadata_2025 huggingface dataset:
Autour de la reine Emma (vers 890-934): Réseaux, itinéraire biographique féminin et questions documentaires au début du Moyen Âge central
Authors: Rosé Isabelle
Published: March 2020

Résumés

L’analyse de réseaux, dans sa dimension quantitative, apparaît à divers titres comme une voie de renouvellement des études historiques, bien qu’il s’agisse d’un outil forgé par la sociologie pour analyser les sociétés contemporaines. Nous proposons d’explorer les difficultés et les apports d’une telle démarche pour l’époque médiévale, en menant une analyse égocentrée du réseau d’Emma (v. 890-934), fille et nièce des souverains robertiens Eudes et Robert, qui épousa le roi des Francs Raoul († 936), dont la trajectoire est éclairée par des sources de différente nature (documents diplomatiques etAnnalesde Flodoard). En resituant cette reine au cœur de ses liens familiaux, il s’agit de comprendre comment fonctionnait le monde aristocratique qui l’entourait, à une période de bouleversement social entre ère carolingienne et époque féodale. L’article aborde les questionnements méthodologiques relatifs au corpus et la manière dont il peut être exploité de façon quantitative. Puis il souligne à quel point l’élaboration d’une base de données et la visualisation des sources par des graphes constituent des outils réflexifs permettant de définir une typologie des liens sociaux et de comprendre les logiques qui ont présidé à l’élaboration des documents. Les bénéfices d’une telle approche sont nombreux, car celle-ci suscite un véritable renouvellement historiographique sur la pratique du pouvoir souverain au cours du premierxe siècle.
Peut-on modéliser la persécution ?: Apports et limites des approches quantifiées sur le terrain de la Shoah
Authors: Mercklé Pierre , Zalc Claire
Published: March 2020

Résumés

L’objectif de cet article est de proposer un examen détaillé des apports et des limites de la modélisation en histoire à partir du cas de la Shoah. Il s’appuie sur une enquête qui a permis de reconstituer les « trajectoires de persécution » des 992 Juifs de Lens pendant la Seconde Guerre mondiale, dont 527 seulement ont survécu. 491 ont été arrêtés, 468 ont été déportés et 449 ont été exterminés. Les données prosopographiques sont utilisées ici pour répondre à une question simple : est-il possible de modéliser la persécution ? En d’autres termes, est-il possible de construire une représentation simplifiée mais heuristique des processus causaux complexes qui ont déterminé les chances de survie face à la persécution nazie à partir de données standardisées sur un nombre relativement important d’individus ? L’article discute les apports et les limites d’une succession de méthodes quantifiées : celles qui s’inscrivent dans ce qu’Andrew Abbott appelle le « programme standard » des sciences sociales, ainsi que l’analyse des réseaux et l’analyse séquentielle. Pour chacune d’entre elles, sont plus particulièrement discutées les manières de rendre compte des interactions entre les individus, de l’historicité des comportements et des processus déterminant ces chances de survie. Les tentatives de modélisation à partir de données historiennes apportent ainsi de véritables renouvellements de connaissances, notamment lorsqu’elles sont menées de manière cumulative sur une même enquête. En passant d’une logique de propriétés individuelles à une logique de trajectoires interconnectées, ces approches permettent de mieux comprendre les interactions sociales et locales, et offrent ainsi des perspectives stimulantes pour la microhistoire de l’Holocauste.
Impact of implementing a competency-based job framework for clinical research professionals on employee turnover
Authors: Stroo Marissa , Asfaw Kirubel , Deeter Christine , Freel Stephanie A. , Brouwer Rebecca J. N. , Hames Betsy , Snyder Denise C.
Published: March 2020

Introduction:

A new competency-based job framework was implemented for clinical research professionals at a large, clinical research-intensive academic medical center. This study evaluates the rates of turnover before and after implementation of the new framework. Turnover in this workforce (as with most) is costly; it contributes to wasted dollars and lost productivity since these are highly specialized positions requiring extensive training, regardless of experience in the field.

Methods:

Trends in employee turnover for 3 years prior to and after the implementation of competency-based job framework for clinical research positions were studied using human resources data. Employee demographics, turnover rates, and comparisons to national statistics are summarized.

Results:

Employee turnover within the clinical research professional jobs has decreased from 23% to 16%, a 45% reduction, since the implementation of competency-based job framework.

Conclusion:

The new jobs and career ladders, both of which are centered on a competency-based framework, have decreased the overall turnover rate in this employee population. Since little is known about the rates of turnover in clinical research, especially in the academic medical setting, the results of this analysis can provide important insights to other academic medical centers on both employee turnover rate in general and the potential impact of implementing large-scale competency-based job changes.
Interdisciplinary engineering of cyber-physical production systems: highlighting the benefits of a combined interdisciplinary modelling approach on the basis of an industrial case
Authors: Vogel-Heuser Birgit , Böhm Markus , Brodeck Felix , Kugler Katharina , Maasen Sabine , Pantförder Dorothea , Zou Minjie , Buchholz Johan , Bauer Harald , Brandl Felix , Lindemann Udo
Published: March 2020

In the context of cross-disciplinary and cross-company cooperation, several challenges in developing manufacturing systems are revealed through industrial use cases. To tackle these challenges, two propositions are used in parallel. First, coupling technical models representing different content areas facilitates the detection of boundary crossing consequences, either by usinga posterioriora prioriconnection. Second, it is necessary to enrich these coupled technical models with team and organizational models as interventions focusing on the collaboration between individuals and teams within broader organizational conditions. Accordingly, a combined interdisciplinary approach is proposed. The feasibility and benefits of the approach is proven with an industrial use case. The use case shows that inconsistencies among teams can be identified by coupling engineering models and that an integrated organizational model can release the modelling process from communication barriers.
Of dreams and nightmares: implementing medical male circumcision in eSwatini (Swaziland)
Authors: Mkhwanazi Nolwazi
Published: March 2020

This article uses the accelerated saturation initiative (ASI) Soka Uncobe, which took place in the kingdom of eSwatini in 2011 and 2012, to comment on HIV humanitarian health interventions in Africa. Soka Uncobe, the first ASI on voluntary medical male circumcision, aimed to circumcise 80 per cent of all HIV-negative men aged fifteen to forty-nine years over a twelve-month period. Using written and verbal accounts, I draw attention to the dreams and hopes behind the design of the initiative. I also highlight the dynamics of the implementation of Soka Uncobe, and, in doing so, I chart the path to its ultimate failure by showing the reluctance of the implementation partners (based mainly in the global North) to take seriously what have now become well-known critiques of why humanitarian interventions fail. Ultimately, I suggest that, despite having the potential to produce some critical results, Soka Uncobe was no different from previous transnational humanitarian health interventions. Thus, an exposé of why it failed is pivotal to this article about the dreams that underpinned the first ever ASI related to medical male circumcision.
Dreams and dream spaces of West African molecular microbiology
Authors: Okeke Iruka N.
Published: March 2020

By the end of the 1990s, molecular approaches predominated in biomedical science, but, for West African scientists, biology could not have ‘gone molecular’ at a worse time. Resource constraints led to knowledge expiry and many discovery dreams were terminated, exported or at least postponed. Pivotal transitions in methodologies, knowledge and resources temporally overlapped with an emergent imperative to address infectious disease in Africa. This prompted new initiatives from global health programmes in the North, which imported visions, disciplinary focus and equipment for new laboratory spaces. A handful of African researchers, however, have reimagined and reconstructed existing laboratories as a means to weave their own dreams. This article examines three such laboratories. It outlines how their equipment was accumulated, the ad hoc ways in which the laboratories are supplied and maintained, their extraordinary accomplishments and their key role as domestic nodes for research. The picture that emerges is one that extends beyond technological acquisition to an enactment of the scientists’ own dreams. Importantly, it is a record of outcomes from those who continued to dream while others stilled their imaginations or became canvases coloured by the dreams of other people.
Labour, laziness and distribution: work imaginaries among the South African unemployed
Authors: Dawson H. J. , Fouksman E.
Published: March 2020

A wealth of new writing has emerged around the future of labour, focusing on thinking beyond employment in imagining the futures of ‘surplus populations’ no longer needed by labour markets. These new imaginaries include radically expanded forms of redistribution, such as unconditional cash transfers or universal basic income. But what are the views of the ‘surplus populations’ themselves? This article uses ethnographic research in an informal settlement in South Africa to understand why the unemployed or precariously employed poor are themselves often reluctant to delink labour and income. In particular, we focus on the discursive use of ‘laziness’ by urban unemployed young men. The varied (and often contradictory) ways in which these men employ the laziness discourse sheds light on the logics linking waged work and money in our informants’ social imaginaries. It illuminates the underlying contradictions and complexities of such logics, including those of gender, relational obligations, expectations of citizenship, and the inevitable tensions between aspirational hopes and economic realities. To begin thinking ‘beyond the proper job’, to use Ferguson and Li's phrase, we must unravel and understand such nuanced logics that continue to bind together hard work, deservingness and cash – even for those left out of labour markets.
Neotraditional authority contested: the corporatization of tradition and the quest for democracy in the Topnaar Traditional Authority, Namibia
Authors: Krämer Mario
Published: March 2020

This article examines two closely related themes: the triangle of tradition, capital and the state; and resistance to neotraditional leadership and local activism for democracy. I investigate an uprising in the Topnaar Traditional Authority in the Erongo region of Namibia by young community activists who aimed to promote democracy in their community in a context of manifold accusations of self-enrichment and corruption against the neotraditional leadership. The article demonstrates that the corporatization of tradition is a double-edged sword: neotraditional leaders expand their local power towards their subjects in the short term, but it often produces severe conflict that may result in the delegitimization of neotraditional authority in the long run. However, the Topnaar youth uprising and quest for democracy was less about challenging neotraditional authority per se and more about replacing the incumbents as well as obtaining a fair share of political power. It resulted from the perception that the neotraditional-cum-corporate ventures no longer served the cause of a common good; this, in turn, contradicted the general ideal of equality among the Topnaar. The corporatization of tradition thus generated local grievances and stimulated demands for democratic participation. Since the uprising gained at least some of its momentum from my research on neotraditional authority, I also reflect on my role.
Èṣù and ethics in the Yorùbá world view
Authors: Oyèláràn Ọlásopé O.
Published: March 2020

Èṣù of the Yorùbá tradition, the custodian of the primordialàṣẹ, embodies the principle of perspicacity and pragmatism that is crucial for the exercise of responsibility by sentient and thinking beings. As such, Èṣù demands the ultimate in consciousness as a basis for just living and for a just measure of reward or sanction. Èṣù calls for painstaking commitment to rigorously distilled information and keen consciousness as preconditions for action of any sort, especially for the exercise of judgement, a compelling gesture of the human will. Scholarly and/or zealous traditions have, however, persistently alienated Èṣù from his native Yorùbá cosmology. This article argues for a need for rehabilitation.
Women’s socioeconomic status and choice of birth control method: an investigation for the case of Turkey
Authors: Karaoğlan Deniz , Saraçoğlu Dürdane Şirin
Published: March 2020

This study investigated whether woman’s education, labour market status and the status within the household have any impact on their birth control behaviour in Turkey. Empirical analyses were implemented using the 2013 Demographic and Health Survey dataset, which includes information on women’s socioeconomic status and their current choice of contraceptives: whether they used any method, and if so, what method they used. Using a bivariate probit model with selection to control for any possible selection bias, the results suggest that whether a woman uses any birth control method, and whether the woman chooses modern methods over traditional methods, are primarily explained by education level and urban/rural residence, and that the determinants of contraceptive use vary across college-educated and non-college-educated women. The results also indicate that non-employed women are less likely to use any birth control method compared with women with regular, full-time jobs. However the effect was statistically insignificant.
Soft law instruments on Arctic investment and sustainable development
Authors: Lim Kong Soon
Published: March 2020

In recent years, two soft law instruments have emerged to promote sustainable development in the Arctic, namely the Arctic Investment Protocol by the World Economic Forum Global Agenda Council on the Arctic and the Arctic Economic Council’s Code of Ethics. These instruments seek to foster sustainable development through responsible investment and good business practices. The emergence of these soft law instruments by non-State actors demonstrates an interest from the business sector and Arctic stakeholders to develop business norms and standards of sustainable development that are specific to the region. In understanding the potential and scope of these instruments, this paper considers the role of both instruments in driving sustainable development in the Arctic.
Differential effects of age at illness onset on verbal memory functions in antipsychotic-naïve schizophrenia patients aged 12–43 years
Authors: Fagerlund Birgitte , Pantelis Christos , Jepsen Jens Richardt Møllegaard , Raghava Jayachandra Mitta , Rostrup Egill , Thomas Marie Bjerregaard , Nielsen Mette Ødegaard , Bojesen Kirsten , Jensen Karsten Gjessing , Stentebjerg-Decara Marie , Klauber Dea Gowers , Rudå Ditte , Ebdrup Bjørn H. , Jessen Kasper , Sigvard Anne , Tangmose Karen , Jeppesen Pia , Correll Christoph U. , Fink-Jensen Anders , Pagsberg Anne Katrine , Glenthøj Birte Yding
Published: March 2020

Background

The typical onset of schizophrenia coincides with the maturational peak in cognition; however, for a significant proportion of patients the onset is before age 18 and after age 30 years. While cognitive deficits are considered core features of schizophrenia, few studies have directly examined the impact of age of illness onset on cognition.

Methods

The aim of the study was to examine if the effects of age on cognition differ between healthy controls (HCs) and patients with schizophrenia at illness onset. We examined 156 first-episode antipsychotic-naïve patients across a wide age span (12–43 years), and 161 age- and sex-matched HCs. Diagnoses were made according to ICD-10 criteria. Cognition was assessed using the Brief Assessment of Cognition in Schizophrenia (BACS), and IQ was estimated using subtests from the Wechsler adult- or child-intelligence scales. Multivariate analysis of covariance (MANCOVA) was used to examine linear and quadratic effects of age on cognitive scores and interactions by group, including sex and parental socioeconomic status as covariates.

Results

There was a significant overall effect of age on BACS and IQ (p < 0.001). Significant group-by-age interactions for verbal memory (for age-squared, p = 0.009), and digit sequencing (for age, p = 0.01; age-squared, p < 0.001), indicated differential age-related trajectories between patients and HCs.

Conclusions

Cognitive functions showing protracted maturation into adulthood, such as verbal memory and verbal working memory, may be particularly impaired in both early- and late-schizophrenia onset. Our findings indicate a potential interaction between the timing of neurodevelopmental maturation and a possible premature age effect in late-onset schizophrenia.
Resource-rationality and dynamic coupling of brains and social environments
Authors: Ross Don
Published: March 2020

Leider and Griffiths clarify the basis for unification between mechanism-driven and solution-driven disciplines and methodologies in cognitive science. But, two outstanding issues arise for their model of resource-rationality: human brains co-process information with their environments, rather than merely adapt to them; and this is expressed in methodological differences between disciplines that complicate Leider and Griffiths’ proposed structural unification.
What is the purpose of cognition?
Authors: Szollosi Aba , Newell Ben R.
Published: March 2020

The purpose of human cognition depends on the problem people try to solve. Defining the purpose is difficult, because people seem capable of representing problems in an infinite number of ways. The way in which the function of cognition develops needs to be central to our theories.
Resource-rational analysis versus resource-rational humans
Authors: Rahnev Dobromir
Published: March 2020

Lieder and Griffiths advocate for resource-rational analysis as a methodological device employed by the experimenter. However, at times this methodological device appears to morph into the substantive claim that humans are actually resource-rational. Such morphing is problematic; the methodological approach used by the experimenter and claims about the nature of human behavior ought to be kept completely separate.
La participation sociale dans les résidences privées pour aînés
Authors: Andrianova Anna , Raymond Émilie
Published: March 2020

Le vieillissement de la population invite à étudier les résidences privées pour aînés, notamment sous l’angle du lien social. Après leur emménagement en résidence, plusieurs aînés veulent continuer de participer activement à la société. Cette recherche qualitative exploratoire a pour objectif de mieux comprendre les perceptions et les expériences d’aînés vivant dans une résidence privée par rapport à leur participation sociale, sur le plan de leurs relations interpersonnelles et de leurs activités de loisirs. Onze entrevues individuelles ont été menées auprès de personnes vivant dans des résidences privées pour aînés de la région de la ville de Québec, au Canada. Sur le plan personnel, les facteurs centraux pour la participation sociale sont l’adaptation au nouveau milieu de vie, l’implication dans ce milieu, notamment par le biais du bénévolat, ainsi que l’état de santé de la personne. En ce qui concerne l’environnement social, les facteurs importants sont la proximité géographique de l’entourage, une offre variée d’activités et la stabilité du personnel. Au final, des recommandations sont formulées au sujet des stratégies d’intervention et des pistes de recherche, lesquelles donnent suite aux constats énoncés, et ce, afin de mieux soutenir la participation sociale en résidence privée pour aînés.
User research enabled by makerspaces: bringing functionality to classical experience prototypes
Authors: Jensen Matilde Bisballe , Steinert Martin
Published: March 2020

This paper sheds light on the new possibilities for user research activities facilitated by access to makerspaces. We present four case studies of user research conducted in two university-based makerspaces as examples of makerspace-driven user research. Further, by comparing the cases to three classical user research activities, namely observation, prototyping, and user journey mapping, we highlight the main aspects of this new context of user research. We find that accessibility to makerspaces enables user researchers to build low-fidelity yet high-functionality prototypes for exploring users’ preferences and motivations in controlled and repeatable ways. These prototypes fall into the category of experience prototypes, but they have greater functionality than the prototypes previously used in this field. Thus, a user researcher can explore a topic more systematically and in a more hypothesis-driven manner. In summary, this study encourages stakeholders in the early stages of product development to consider a makerspace as a resource for user-related requirement elicitation rather than for only specific product iteration.
The Undeserving Sick? An Evaluation of Patients’ Responsibility for Their Health Condition
Authors: CLAVIEN CHRISTINE , HURST SAMIA
Published: March 2020

The recent increased prevalence of diseases related to unhealthy lifestyles raises difficulties for healthcare insurance systems traditionally based on the principles of risk-management, solidarity, and selective altruism: since these diseases are, to some extent, predictable and avoidable, patients seem to bear some responsibility for their condition and may not deserve full access to social medical services. Here, we investigate with objective criteria to what extent it is warranted to hold patients responsible for their illness and to sanction them accordingly. We ground our analysis on a series of minimal conditions for ‘practical’ and for ‘moral’ responsibility attribution. By applying these criteria consistently, we highlight that individual responsibility applies to risk-taking life choices rather than stigmatized sickness. We explain that responsibility is a matter of degree, that it varies across life-history, and can be affected by factors beyond the patients’ grasp. We point out that scientific knowledge about the effect of these factors generates responsibilities for other parties such as public health agencies and private industry. The upshot of our analysis is that health policies targeting the ‘liable’ undeserving sick are mostly unwarranted, and tend to increase unequal treatment of already vulnerable groups: the unlucky sick.
Implementation of a specialized program to treat violence in a forensic population
Authors: Velasquez Susan , Bauchowitz Andrea , Pyo David , Pollock Megan
Published: March 2020

A shift within state psychiatric hospitals toward serving a predominantly forensic population has resulted in increased violent incidents within those settings. Thus, addressing criminogenic needs in addition to mental illness is an important paradigm shift. Relying on seclusion or restraint as the primary mechanisms to address violence interferes with the provision of effective care to patients struggling with aggressive behaviors. Implementing new treatment programs aimed at reducing violence in forensic inpatient settings is warranted. This article focuses on the step-by-step process of developing such a specialized treatment program within the California Department of State Hospitals. Leadership within this hospital system collaborated with labor unions and other stakeholders to obtain funding to create a novel treatment environment. This treatment program includes a ward design aimed to improve safety and delivers treatment based on the Risk Needs Responsivity Model. Treatment is guided by violence risk assessment and primarily focused on addressing criminogenic needs. The selection of treatments with a focus on violence reduction is discussed.
Why We Might Just Be Living in a Second “Progressive” Era
Authors: Cook Eli
Published: March 2020

The recent framing of our current era as a “Second Gilded Age” has been closely linked to economist Thomas Piketty's empirical findings regarding income inequality patterns in American history. Yet if we take a closer look at both the inequality data at our disposal as well as the broader social forces that have led to widening wealth gaps in recent decades, it becomes apparent that our current neoliberal era of rising inequality is far more similar to the Progressive Era than the Gilded Age. After arguing why the Progressive Era is a more apt historical analogy, this article will seek to explain why our contemporary moment has nonetheless been framed as a Second Gilded Age.
Two kinematically different Large Magellanic Cloud old globular cluster populations unveiled from Gaia DR2 data sets
Authors: Piatti Andrés E. , Alfaro Emilio J. , Cantat-Gaudin Tristan
Published: March 2020

We derive mean proper motions of 15 known Large Magellanic Cloud (LMC) old globular clusters (GCs) from the Gaia DR2 data sets. When these mean proper motions are gathered with existent radial velocities to compose the GCs’ velocity vectors, we found that the projection of the velocity vectors onto the LMC plane and those perpendicular to it tell us about two distinct kinematical GC populations. Such a distinction becomes clear if the GCs are split at a perpendicular velocity of 10 km/s (absolute value). The two different kinematics groups also exhibit different spatial distributions. Those with smaller vertical velocities are part of the LMC disk, while those with larger values are closely distributed like a spheroidal component. Since GCs in both kinematic-structural components share similar ages and metallicities, we speculate with the possibility that their origins could have occurred through a fast collapse that formed halo and disk concurrently.
Observations meets theory in clustered star formation
Authors: Pfalzner Susanne
Published: March 2020

Stars form predominantly in groups which display a broad spectrum of masses, sizes, and other properties. Despite this diversity there exist an underlying structure that can constrain cluster formation theories. We show how combining observations with simulations allows us to disclose this underlying structure. One example is the mass-radius relation for young embedded associations which follows ${M_c} = CR_c^\gamma $ with γ = 1.7 ± 0.2.0.2, which is directly related to the mass-radius relation of clumps. Results based on GAIA DR2 have demonstrated that young stellar groups (1–5 Myr) expand and that this expansion process is largely over by an age of 10–20 Myr. Such a behaviour is expected within the gas expulsion scenario. However, the effect of gas expulsion depends strongly on the SFE, the gas expulsion time scale, etc. Here it is demonstrated how existing and upcoming data are able to constrain these parameters and correspondingly the underlying models.
The ecology of the galactic centre: Nuclear stellar clusters and supermassive black holes
Authors: Davies Melvyn B. , Askar Abbas , Church Ross P.
Published: March 2020

Supermassive black holes are found in most galactic nuclei. A large fraction of these nuclei also contain a nuclear stellar cluster surrounding the black hole. Here we consider the idea that the nuclear stellar cluster formed first and that the supermassive black hole grew later. In particular we consider the merger of three stellar clusters to form a nuclear stellar cluster, where some of these clusters contain a single intermediate-mass black hole (IMBH). In the cases where multiple clusters contain IMBHs, we discuss whether the black holes are likely to merge and whether such mergers are likely to result in the ejection of the merged black hole from the nuclear stellar cluster. In some cases, no supermassive black hole will form as any merger product is not retained. This is a natural pathway to explain those galactic nuclei that contain a nuclear stellar cluster but apparently lack a supermassive black hole; M33 being a nearby example. Alternatively, if an IMBH merger product is retained within the nuclear stellar cluster, it may subsequently grow, e.g. via the tidal disruption of stars, to form a supermassive black hole.
A simple two-component description of mass segregation for anisotropic globular clusters
Authors: Torniamenti S. , Bertin G. , Bianchini P.
Published: March 2020

As a result of the slow action of two-body encounters, globular clusters develop mass segregation and attain a condition of only partial energy equipartition even in their central, most relaxed regions. Realistic numerical simulations show that, during the process, a radially-biased anisotropy profile slowly builds up, mimicking that resulting from incomplete violent relaxation. Commonly used dynamical models, such as the one-component King models, cannot describe these properties. Here we show that simple two-component models based on a distribution function originally conceived to describe elliptical galaxies, recently truncated and adapted to the context of globular clusters, can describe in detail what is observed in complex and realistic numerical simulations.
Unexpected kinematics of multiple populations in globular clusters
Authors: Dalessandro Emanuele
Published: March 2020

Present-day structural and kinematical properties of multiple populations (MPs) can provide useful information about the physical mechanisms driving the formation and early evolution of globular clusters (GCs). As part of a large project aimed at characterizing the kinematics of MPs, here we present a detailed multi-epoch analysis of the low-mass GC NGC6362. We find that MPs in this system show significant differences in their line-of-sight velocity dispersion profiles. This result is totally unexpected given the dynamical age and fraction of mass lost by NGC6362. We also find that the binary fraction is remarkably larger in the first (FP) than in the second population (SP). We show that such a difference can efficiently inflate the velocity dispersion of FP at intermediate/large cluster-centric distances with respect to SP. Indeed, our results nicely match the predictions of state-of-the art N-body simulations of the co-evolution of MPs in GCs including the effect of binaries.
Hunting for Globular Clusters in the early universe
Authors: Phipps Frederika , Khochfar Sadegh , Lisa Varri Anna
Published: March 2020

Setting the formation of globular clusters (GCs) within a cosmological context and characterising the properties of proto-GCs at high redshift is currently a major challenge. In this work, we address that challenge by exploring a suit of high-resolution cosmological simulations from the First Billion Years (FiBY) project z at ⩾6 to investigate theoretical scenarios concerning the formation of old, low-mass stellar systems with a particular focus on GCs. Two distinct groups of objects are identified in the simulations. The first group of objects, with a high baryon fraction, we associate with proto-GCs. The second group, that exhibit a high stellar fraction, could be forming ultra-faint dwarf galaxies (UFDs). The objects with high baryon fraction are promising proto-GC candidates because they have little to no dark matter (DM), have number densities consistent with predictions from the literature, are very compact and have a high stellar density. We fit and also assess the redshift-zero globular system mass - halo mass relation and find it provides a reasonable fit to our proto-GC objects, indicating that this relation is likely set at formation.
MOCCA survey database I: Preliminary mock Extra Galactic Globular Cluster observations
Authors: Leveque Agostino , Giersz Mirosław
Published: March 2020

The photometric properties that we could observe for Extra-Galactic Globular Clusters (EGGCs) are the integrated light of the system and for nearby EGGCs it also is possible to measure both half-light radii and the color spatial distribution, e.g. for areas smaller and larger than the half-light radius. No information about the internal dynamical state of the system could be directly obtained from observations. On the other hand, simulations of Globular Clusters (GCs) can provide detailed information about the dynamical evolution of the system.

We present a preliminary study of EGGCs’ photometric properties for different dynamical evolutionary stages. We apply this study to 12Gyr old GCs simulated as part of the MOCCA Survey Database. We determine the magnitudes in different bands from their projected snapshots using the Flexible Stellar Population Synthesis (FSPS) code and we measure the half-light radii from the surface brightness.
Are most Cataclysmic Variables in Globular Clusters dynamically formed?
Authors: Belloni Diogo , Giersz Mirek , Sandoval Liliana E. Rivera , Askar Abbas , Ciecielag Pawel
Published: March 2020

We have been investigating populations of cataclysmic variables (CVs) in a set of more than 300 globular cluster (GC) models evolved with themoccacode.[-120pt] One of the main questions we have intended to answer is whether most CVs in GCs are dynamically formed or not. Contrary to what has been argued for a long time, we found that dynamical destruction of primordial CV progenitors is much stronger in GCs than dynamical formation of CVs. In particular, we found that, on average, the detectable CV population is predominantly composed of CVs formed via a typical common envelope phase (≳70 per cent). However, core-collapsed models tend to have higher fractions of bright CVs than non-core-collapsed ones, which suggests then that the formation of CVs is indeed slightly favoured through strong dynamical interactions in core-collapsed GCs, due to the high stellar densities in their cores.
What do globular clusters tell us about isolated ellipticals? The case of NGC 6411
Authors: Caso J. P. , Bassino Lilia P. , Richtler T. , Salinas R.
Published: March 2020

We summarize the results from a study of the globular cluster (GC) system of the isolated elliptical galaxy NGC 6411, based on Gemini/GMOS g', r', i’ photometry. The extent of the globular cluster system is about 70 kpc. It contains ≍700 members. The colour distribution and luminosity function are typical of old GC systems. An excess of bright GCs with intermediate colours might evidence an intermediate-age merger.
Do three-body encounters in galactic nuclei affect compact binary merger rates?
Authors: Trani Alessandro A.
Published: March 2020

High-density cusps of compact remnants are expected to form around supermassive black holes (SMBHs) in galactic nuclei via dynamical friction and two-body relaxation. Due to the high density, binaries in orbit around the SMBH can frequently undergo close encounters with compact remnants from the cusp. This can affect the gravitational wave merger rate of compact binaries in galactic nuclei. We investigated this process by means of high accuracy few-body simulations, performed with a novel Monte Carlo approach. We find that, around a SgrA*-like SMBH, three-body encounters increase the number of mergers by a factor of 3. This occurs because close encounters can reorient binaries with respect to their orbital plane around the SMBH, increasing the number of Kozai-Lidov induced mergers. We obtain a binary black hole merger rate of ГMW = 1.6 × 10−6 yr−1 per Milky Way-like nucleus.
A linear stability study of stellar rotating spheres
Authors: Rozier Simon , Fouvry Jean-Baptiste , Breen Philip G. , Varri Anna Lisa , Pichon Christophe , Heggie Douglas C.
Published: March 2020

Recent observations of globular clusters imposed major revisions to the previous paradigm, in which they were considered to be isotropic in velocity space and non-rotating. However, the theory of collisionless spheroids with some kinematic richness has seldom been studied. We present here a first step in this direction, owing to new results regarding the linear stability of rotating Plummer spheres, with varying anisotropy in velocity space and total amount of angular momentum. We extend the well-known radial orbit instability to rotating systems, and discover a new regime of instability in fast rotating, tangentially anisotropic systems.
Black holes and rotation: Internal kinematics of star clusters with MUSE
Authors: Kamann Sebastian
Published: March 2020

Over the last decade, our abilities to observe the internal kinematics of star clusters have drastically increased. Where a few years back only small numbers of bright stars with radial velocity measurements were available, we can nowadays study the three-dimensional motions of large stellar samples, thanks to the combined datasets gathered by state-of-art spectrographs and astrometric satellites. In this work, I summarise the contribution of integral-field spectrographs, in particular MUSE, to this paradigm change. Using dedicated software tools, we were able to overcome a fundamental limitation of spectroscopy and advance to the crowded cluster centres. This allowed us to study the central kinematics in unprecedented detail and to start uncovering the populations of black holes that reside in massive star clusters.
3 things they don’t tell you about star clusters
Authors: Renaud Florent
Published: March 2020

Dense stellar systems in general and star clusters in particular have recently regained the interest of the extragalactic and even cosmology communities, due to the role they could play as actors and probes of re-ionization, galactic archeology and the dark matter content of galaxies, among many others. In the era of the exploitation and the preparation of large stellar surveys (Gaia, APOGEE, 4MOST, WEAVE), of the detection of gravitational waves mostly originating from dense regions like the cores of clusters (Ligo, LISA), and in an always more holistic view of galaxy formation (HARMONI, Euclid, LSST†), a complete theory on the formation and evolution of clusters is needed to interpret the on-going and forthcoming data avalanche. In this context, the community carries an effort to model the aspects of star cluster formation and evolution in galactic and even cosmological context. However, it is not always easy to understand the caveats and the shortcuts taken in theories and simulations, and their implications on the conclusions drawn. I take the opportunity of this document to highlight three of these topics and discuss why some shortcuts taken by the community are or could be misleading.
RR Lyrae analysis in the Local Group globular clusters and dwarf galaxies
Authors: Benkortem Saruta , Tanakul Nahathai , Suwannajak Chutipong
Published: March 2020

RR Lyrae variables are powerful tools to study their host stellar populations. Globular clusters and dwarf galaxies are old and usually host this type of variables. With a growing number of low luminosity objects discovered in the halo of the Milky Way, classifying stars clusters and galaxies has become more challenging. In this study, we examine the properties of RR Lyrae stars in globular clusters and dwarf galaxies in the Local Group. We construct a catalog of RR Lyrae variables in the Local Group globular clusters and dwarf galaxies from previously published data and compare the properties of RR Lyrae variables between those two types of stellar systems. Our goal is to search for a physical difference in the properties of RR Lyrae variables in those two classes of stellar systems. We also analyze the global trend of RRLs in these systems to understand more about their formation and evolution history.
Detecting the dark matter halos with star clusters in M31/M33 with PFS, SDSS-V and LAMOST
Authors: Fan Zhou , Haysahi Kohei , Zhao Jingkun , Zhao Gang
Published: March 2020

Since a great number of star stream and substructures near M31/M33 have been discovered in Pan-Andromeda Archaeological Survey (PAndAS) and variations of star stream density may trace the dark matter sub-halos, it is good opportunity to study the dark matter sub-halos with the star streams. Further it has been proved that dozens of halo star clusters have the relations with the star stream. As Prime Focus Spectroscopy (PFS) of the 8.2-m Subaru telescope have the powerful ability (I ∼ 22.3 mag) to observe ∼ 2400 objects at a time, it can be used to observe the giant star streams, faint halo star clusters and dwarf galaxies, which provides excellent opportunity to investigate the sub-halos of M31. In addition, we are involved with the Local Volume Mapper (LVM) of SDSS-V program, which may also provide more informations for the star clusters of the Local Group, especially for M31. Finally since we have done series of work with Large Sky Area Multi-Object Fiber Spectroscopic Telescope (LAMOST), we will continue the spectroscopic observations for more star clusters and giant stars of M31/M33.
Abundance of zirconium in the atmospheres of red giants in Galactic globular cluster 47 Tuc
Authors: Kolomiecas Edgaras , Dobrovolskas Vidas , Kučinskas Arūnas
Published: March 2020

We determined zirconium abundance in the atmospheres of 327 red giant branch (RGB) stars in the globular cluster 47 Tuc. The 1D LTE abundances were obtained from the archival VLT GIRAFFE spectra, using 1D hydrostaticATLAS9 stellar model atmospheres and synthetic Zr I line profiles computed with theSYNTHE package. The average zirconium abundance determined in the sample of RGB stars, 〈[Zr/Fe]〉 = +0.38 ± 0.12, agrees well with zirconium abundances obtained at this metallicity in the Galactic field stars, as well as with those observed in other Galactic globular clusters.
Formation and evolution of globular clusters in cosmological simulations
Authors: Li Hui , Gnedin Oleg
Published: March 2020

In a series of three papers, we introduced a novel cluster formation model that describes the formation, growth, and disruption of star clusters in high-resolution cosmological simulations. We tested this model on a Milky Way-sized galaxy and found that various properties of young massive clusters, such as the mass function and formation efficiency, are consistent with observations in the local universe. Interestingly, most massive clusters – globular cluster candidates – are preferentially formed during major merger events. We follow the dynamical evolution of clusters in the galactic tidal field. Due to tidal disruption, the cluster mass function evolves from initial power law to a peaked shape. The surviving clusters at z = 0 show a broad range of metallicity [Fe/H] from -3 to -0.5. A robust prediction of the model is the age–metallicity relation, in which metal-rich clusters are systematically younger than metal-poor clusters by up to 3 Gyr.
Multiple populations in globular clusters: New insights from chemical evolution and horizontal-branch models
Authors: Lee Young-Wook , Kim Jenny J. , Jang Sohee , Chung Chul , Lim Dongwook , Hong Seungsoo
Published: March 2020

In order to investigate the origin of multiple populations in globular clusters (GCs), we have constructed new chemical evolution models for proto-GCs where the supernova blast waves undergo blowout without expelling the ambient gas. Chemical enrichments in our models are then dictated by the winds of massive stars together with the asymptotic-giant-branch stars ejecta. We find that the observed Na-O anti-correlation can be reproduced when multiple episodes of starburst and enrichment are allowed to continue in proto-GCs. The “mass budget problem” is mostly resolved by our models without ad-hoc assumptions on star formation efficiency, initial mass function, and significant loss of first-generation stars. Interestingly, ages and chemical abundances predicted by this chemical evolution model are in good agreements with those independently obtained from our stellar evolution model for the horizontal-branch. We also discuss observational evidence for the GC-like multiple populations in the Milky Way bulge.
Young massive clusters in Arp 299
Authors: Randriamanakoto Zara , Väisänen Petri
Published: March 2020

Because of their young ages and compact densities, young massive star clusters (YMCs) are widely considered as potential proto-globular clusters. They are ubiquitous in environments with ongoing star formation activity such as interacting luminous infrared galaxies. To determine the galactic environmental effects on the star cluster formation and evolution, we study the YMC population of Arp 299 (NGC 3690E/NGC 3690W) using data taken with the HST WFC3/UVIS camera. By fitting the multiband photometry with the Yggdrasil models, we derive the star cluster masses, ages and extinction. While the cluster mass-galactocentric radius relation of NGC 3690E indicates that there could be an influence of the gas density distribution on the cluster formation, the age distribution of the western component suggests that YMCs in that galaxy endure stronger disruption mechanisms. With a cluster formation efficiency of 19 percent, star formation happening in bound clusters in Arp 299 is 3–5 times higher than that of a typical normal spiral.
Multiple bursts of star formation in young star clusters: The case of the Orion Nebula Cluster
Authors: Jerabkova Tereza
Published: March 2020

Young star clusters (YSCs) with resolved stellar populations are well suited for studying star-cluster formation. In most cases, the (pre-main-sequence) stellar populations found in the YSCs are coeval with an intrinsic age spread of up to 1Myr. Such observations can be understood as the YSCs having formed in one burst, which star formation was truncated by stellar feedback. The recent discovery that the colour-magnitude diagram of the Orion Nebula Clusters (ONC) contains three well defined age-separated populations appears to shatter this model. The implication is that the ONC formed in three bursts, with star formation still on-going in the last burst. We present new observational results focusing on the three populations in the ONC using OmegaCAM photometry and Gaia DR2 measurements. We also describe a theoretical model which may explain these observations by an interplay between stellar feedback and cluster dynamics.
Spectroscopic studies of stellar populations in globular clusters and field stars: Implications for globular cluster and Milky Way halo formation
Authors: Gratton Raffaele
Published: March 2020

We review spectroscopic results concerning multiple stellar populations in globular clusters. The cluster initial mass is the most important parameter determining the fraction of second generation stars. The threshold for the onset of the multiple population phenomenon is 1–3×105 M⊙. Nucleosynthesis is influenced by metallicity: Na/O and Mg/Al anti-correlations are more extended in metal-poor than in metal-rich clusters. Massive clusters are more complex systems than the smaller ones, with several populations characterized by different chemical compositions. The high Li abundance observed in the intermediate second generation stars strongly favours intermediate mass AGB stars as polluters for this class of stars; however, it is well possible that the polluters of extreme second generation stars, that often do not have measurable Li, may be fast rotating massive stars or super-massive stars. The mass budget factor should be a function of the cluster mass, and needs to be large only in massive clusters.