bluuebunny/crossref_metadata_2025_split huggingface dataset:
Inter-cluster velocity structures of star cluster complexes
Authors: Fujii Michiko S. 
Published: March 2020

AbstractStar 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

AbstractThe 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

AbstractWe 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

AbstractWe 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

AbstractSome 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

AbstractI 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.
Super star clusters and their multiple stellar populations
Authors: Zinnecker Hans 
Published: March 2020

AbstractWe present a scenario for the formation of super star clusters (with masses larger than 105 M⊙) in which multiple generations of star formation will occur. We stress that the gas left over (∼50%) from first generation (1G) star formation should be retained in such massive clusters (thanks to their deep potential wells, with escape speeds larger than 10 km/s) and be available for a second or even third generation of stars, with the basic HeCNONaMgAl chemical anomalies observed in globular clusters, the latter assumed to be the descendents of these super star clusters. One new feature of this model is the role of C+ cooling of the dense warm trapped neutral or ionized gas which defines a characteristic temperature of ∼100 K, leading to a second generation (2G) of stars with a top-heavy IMF (M > 5 M⊙). The ashes of the 2G very massive stars (VMS, M > 100 M⊙) sampled in this IMF quickly pollute and dilute the left-over pristine gas with their slow winds (that cannot escape the cluster), while the majority of massive stars develop fast winds (that actually can escape from the cluster). Meanwhile, much of the remaining dense T = 100 K gas contracts gravitationally in the massive cluster and may reach densities of the order of 109 cm−3, in which case the Jeans mass drops to about 0.2 M⊙ and leads to a substantial low-mass pre-MS 3G population (most likely on a very short timescale). In this way, we may solve both the mass budget and the excess Helium problem in proto-globular clusters, while also explaining the Na-O and Mg-Al anti-correlations resulting from hot H-burning of very massive stars at 45MK and 75MK, respectively.
A new method to simulate long-term evolution of stars near a massive Black Hole
Authors: Funato Y. 
Published: March 2020

AbstractN-body simulation is the necessary tool to investigate the evolution of star clusters. It is important to develop a time integration method which guarantees the appropriate accuracy and calculation cost.Here we present a new simple method for long term simulation of stars around a massive black hole in stellar systems. Usually the time integration orbits of stars revolving a massive black hole requires much simulation time. We introduce a time transformation which is a kind of ”inverse KS regularization” of time. Using our method, the integration of the long term evolution near a black hole (BH) becomes easier, especially applied to relatively large star clusters and the Galactic Center.
An empirical clock to measure the dynamical age of star clusters
Authors: Ferraro Francesco R. 
Published: March 2020

AbstractThe observational properties of a special class of stars (the so-called Blue Straggler stars - BSSs) in Globular Clusters are discussed in the framework of using this stellar population as probe of the dynamical processes occurring in high-density stellar systems. In particular, the shape of the BSS radial distribution and their level of central segregation have been found to be powerful tracers of the level of the dynamical evolution of the hosting cluster, thus allowing the definition of an empirical chronometer able to measure the dynamical age of star clusters.
Multiple stellar populations: From old Milky Way globulars to young star clusters
Authors: Marino Anna F. 
Published: March 2020

AbstractI present the latest results from our group about the multiple stellar populations in the old Milky Way globular clusters (GCs) and in the young systems both in the Magellanic Clouds and in the Milky Way. For the ancient GCs in our Galaxy I summarize the chemical properties of the stellar populations as observed on the chromosome map. Both Type I and Type II GCs are discussed. For the youngest clusters I will briefly report our latest spectroscopic analysis on the Large Magellanic Cloud cluster NGC 1818 and the Galactic open cluster M 11, which supports the co-existence of stellar populations with different rotation rates.
Associations of Age and Pain With 9-Year Functional Health Trajectories
Authors: Wettstein Markus , Spuling Svenja M. , Cengia Anja , Nowossadeck Sonja , Tesarz Jonas 
Published: March 2020

Abstract. We investigated whether information-processing speed and accommodative coping moderate associations of age and pain with 9-year functional health trajectories. Our sample consisted of 5,254 participants of the German Ageing Survey aged 40 years and older ( M = 62.33 years) who participated in up to four measurement occasions. After controlling for sex, chronic diseases, and education, our longitudinal multilevel regression models revealed that the association of older age and higher pain severity with lower functional health was weaker in individuals with higher processing speed. The relationship between pain and functional health was weaker in individuals with higher scores on accommodative coping. Our findings suggest that processing speed and accommodative coping may be important compensatory resources buffering negative associations of age and pain with functional health.
Modeling the Microwave Emission of Snow on Arctic Sea Ice for Estimating the Uncertainty of Satellite Retrievals
Authors: Rostosky P. , Spreen G. , Gerland S. , Huntemann M. , Mech M. 
Published: March 2020

AbstractWithin a rapidly changing Arctic climate system, snow on sea ice is an important climate parameter. A common method to derive snow depth on an Arctic‐wide scale is based on passive microwave satellite observations. However, the uncertainties of this method are not well constrained. In this study, we estimate the influence of geophysical parameters, including ice, snow, and atmospheric properties on passive microwave snow depth retrievals using a Monte Carlo uncertainty estimation. The results are based on model simulations from the Microwave Emission Model for Layered Snowpacks, the SNOWPACK model, and from the Passive and Active Microwave TRAnsfer model. All simulations are based on in situ observations obtained during the N‐ICE2015 campaign. The average uncertainty in potential snow depth retrievals is between 11% and 19%, depending on the microwave frequencies used and increases with increasing snow depth. For lower‐frequency retrievals (including 6.9 GHz), unknown snow properties are the strongest source of uncertainty while for higher‐frequency retrievals (including 36.5 GHz), the contribution of ice, snow properties, and clouds is equally strong.
Structures of peptide-free and partially loaded MHC class I molecules reveal mechanisms of peptide selection
Authors: Anjanappa Raghavendra , Garcia-Alai Maria , Kopicki Janine-Denise , Lockhauserbäumer Julia , Aboelmagd Mohamed , Hinrichs Janina , Nemtanu Ioana Maria , Uetrecht Charlotte , Zacharias Martin , Springer Sebastian , Meijers Rob 
Published: March 2020

AbstractMajor Histocompatibility Complex (MHC) class I molecules selectively bind peptides for presentation to cytotoxic T cells. The peptide-free state of these molecules is not well understood. Here, we characterize a disulfide-stabilized version of the human class I molecule HLA-A*02:01 that is stable in the absence of peptide and can readily exchange cognate peptides. We present X-ray crystal structures of the peptide-free state of HLA-A*02:01, together with structures that have dipeptides bound in the A and F pockets. These structural snapshots reveal that the amino acid side chains lining the binding pockets switch in a coordinated fashion between a peptide-free unlocked state and a peptide-bound locked state. Molecular dynamics simulations suggest that the opening and closing of the F pocket affects peptide ligand conformations in adjacent binding pockets. We propose that peptide binding is co-determined by synergy between the binding pockets of the MHC molecule.
An organoid biobank for childhood kidney cancers that captures disease and tissue heterogeneity
Authors: Calandrini Camilla , Schutgens Frans , Oka Rurika , Margaritis Thanasis , Candelli Tito , Mathijsen Luka , Ammerlaan Carola , van Ineveld Ravian L. , Derakhshan Sepide , de Haan Sanne , Dolman Emmy , Lijnzaad Philip , Custers Lars , Begthel Harry , Kerstens Hindrik H. D. , Visser Lindy L. , Rookmaaker Maarten , Verhaar Marianne , Tytgat Godelieve A. M. , Kemmeren Patrick , de Krijger Ronald R. , Al-Saadi Reem , Pritchard-Jones Kathy , Kool Marcel , Rios Anne C. , van den Heuvel-Eibrink Marry M. , Molenaar Jan J. , van Boxtel Ruben , Holstege Frank C. P. , Clevers Hans , Drost Jarno 
Published: March 2020

AbstractKidney tumours are among the most common solid tumours in children, comprising distinct subtypes differing in many aspects, including cell-of-origin, genetics, and pathology. Pre-clinical cell models capturing the disease heterogeneity are currently lacking. Here, we describe the first paediatric cancer organoid biobank. It contains tumour and matching normal kidney organoids from over 50 children with different subtypes of kidney cancer, including Wilms tumours, malignant rhabdoid tumours, renal cell carcinomas, and congenital mesoblastic nephromas. Paediatric kidney tumour organoids retain key properties of native tumours, useful for revealing patient-specific drug sensitivities. Using single cell RNA-sequencing and high resolution 3D imaging, we further demonstrate that organoid cultures derived from Wilms tumours consist of multiple different cell types, including epithelial, stromal and blastemal-like cells. Our organoid biobank captures the heterogeneity of paediatric kidney tumours, providing a representative collection of well-characterised models for basic cancer research, drug-screening and personalised medicine.
Visualization of autoantibodies and neutrophils in vivo identifies novel checkpoints in autoantibody-induced tissue injury
Authors: Hundt Jennifer E. , Iwata Hiroaki , Pieper Mario , Pfündl Rebecca , Bieber Katja , Zillikens Detlef , König Peter , Ludwig Ralf J. 
Published: March 2020

AbstractIn several autoimmune diseases, e.g., pemphigoid disease (PD), autoantibodies are the direct cause of pathology. Albeit key requirements for antibody-mediated diseases were identified, their interactions and exact temporal and spatial interactions remained elusive. The skin is easily accessible for imaging. Thus, we selected epidermolysis bullosa acquisita (EBA), a PD with autoantibodies to type VII collagen (COL7), to visualize interactions of autoantibodies, target tissue and effector cells (neutrophils). Following injection into mice, anti-COL7 IgG bound to the dermal-epidermal junction (DEJ) within minutes. We unexpectedly observed an inhomogeneous distribution of autoantibodies along the DEJ. Thus, we hypothesized that specific external triggers may affect autoantibody distribution. Indeed, mechanical irritation led to an increased autoantibody binding along the DEJ. Subsequently, anti-COL7 IgG was injected into mice expressing green fluorescent protein under the LysM promoter (LysM-eGFP) mice. This allows to visualize myeloid cellsin vivoin these animals. Using multiphoton imaging, we observed a limited extravasation of LysM-eGFP+cells into skin was observed within 24 hours. Intriguingly, LysM-eGFP+cells did not immediately co-localize with autoantibodies, which was only noted at later time points. Of note, interactions of LysM-eGFP+with the autoantibodies at the DEJ were short-lived. Collectively, our results define the following checkpoints for autoantibody-induced tissue injury: (i) autoantibody egress to target tissue influenced by mechanical trigger factors, (ii) neutrophil recruitment into the vicinity of autoantibody deposits and (iii) short-term neutrophil localization to these deposits, as well as (iv) delayed recruitment of neutrophils with subsequent autoantibody-induced inflammation.
Safety and Effectiveness of Neuro-thrombectomy on Single compared to Biplane Angiography Systems
Authors: Guenego Adrien , Mosimann Pascal J. , Wintermark Max , Heit Jeremy J. , Zuber Kevin , Dobrocky Tomas , Lotterie Jean Albert , Nicholson Patrick , Marcellus David G. , Olivot Jean Marc , Gonzalez Nestor , Blanc Raphaël , Pereira Vitor Mendes , Gralla Jan , Kaesmacher Johannes , Fahed Robert , Piotin Michel , Cognard Christophe ,   The RADON Investigators, Piechowiak Eike , Mordasini Pasquale , Zibold Felix , Ducroux Celina , Bonneville Fabrice , Darcourt Jean , Vukasinovic Ivan , Januel Anne Christine , Monfraix Sylvie , Michelozzi Caterina , Tall Philippe , Mazighi Mikael , Desilles Jean-Philippe , Ciccio Gabriele , Smajda Stanislas , Redjem Hocine , Maier Benjamin , Martin Blake W. , Guenego Elisa , Carbillet Fanny 
Published: March 2020

AbstractAn increasing number of centers not necessarily equipped with biplane (BP) angiosuites are performing mechanical thrombectomy (MT) in acute ischemic stroke patients. We assessed whether MT performed on single-plane (SP) is equivalent in terms of safety, effectiveness, radiation and contrast agent exposure. Consecutive patients treated by MT in four high volume centers between January 2014 and May 2017 were included. Demographic and MT characteristics were assessed and compared between SP and BP. Of 906 patients treated by MT, 576 (64%) were handled on a BP system. After multivariate analysis, contrast load and fluoroscopy duration were significantly lower in the BP group [100vs200mL, relative effect 0.85 (CI: 0.79–0.92), p = 0.0002; 22 vs 27 min, relative effect 0.84 (CI: 0.76–0.93), p = 0.0008, respectively]. There was no difference in recanalization (modified Thrombolysis-In-Cerebral-Infarction 2b-3), good clinical outcome (modified Rankin Scale 0–2), complications rates, procedure duration or radiation exposure. A three-vessel diagnostic angiogram performed prior to MT led to a significant increase in procedure duration (15% increase, p = 0.05), radiation exposure (33% increase, p < 0.0001) and contrast load (125% increase, p < 0.0001). Mechanical neuro-thrombectomy seems equally safe and effective on a single or biplane angiography system despite increased contrast load and fluoroscopy duration on the former.
Chronic disturbance modulates symbiont (Symbiodiniaceae) beta diversity on a coral reef
Authors: Claar Danielle C. , Tietjen Kristina L. , Cox Kieran D. , Gates Ruth D. , Baum Julia K. 
Published: March 2020

AbstractChronic disturbance can disrupt ecological interactions including the foundational symbiosis between reef-building corals and the dinoflagellate family Symbiodiniaceae. Symbiodiniaceae are photosynthetic endosymbionts necessary for coral survival, but many Symbiodiniaceae can also be found free-living in the environment. Since most coral species acquire new Symbiodiniaceae from the environment each generation, free-living Symbiodiniaceae represent important pools for coral symbiont acquisition. Yet, little is known about the diversity of, or impacts of disturbance on, free-living Symbiodiniaceae. To determine how chronic and pulse disturbances influence Symbiodiniaceae communities, we sampled three reef habitat compartments - sediment, water, and coral (Pocillopora grandis, Montipora aequituberculata, Porites lobata) - at sites exposed to different levels of chronic anthropogenic disturbance, before, during, and after a major storm. Almost no (4%) Symbiodiniaceae amplicon sequence variants (ASVs) were found in all three compartments, and over half were found uniquely in coral. Sites experiencing chronic disturbance were typically associated with higher symbiont beta diversity (i.e., variability and turnover) across reef habitat compartments. Pulse stress, from the storm, exhibited some influence on symbiont beta diversity but the effect was inconsistent. This suggests that in this ecosystem, the effects of chronic disturbance are more prominent than temporal variability during a pulse disturbance for shaping symbiont communities.
Gene-environment interactions due to quantile-specific heritability of triglyceride and VLDL concentrations
Authors: Williams Paul T. 
Published: March 2020

Abstract“Quantile-dependent expressivity” is a dependence of genetic effects on whether the phenotype (e.g., triglycerides) is high or low relative to its distribution in the population. Quantile-specific offspring-parent regression slopes (βOP) were estimated by quantile regression for 6227 offspring-parent pairs. Quantile-specific heritability (h2), estimated by 2βOP/(1 + rspouse), decreased 0.0047 ± 0.0007 (P = 2.9 × 10−14) for each one-percent decrement in fasting triglyceride concentrations, i.e., h2 ± SE were: 0.428 ± 0.059, 0.230 ± 0.030, 0.111 ± 0.015, 0.050 ± 0.016, and 0.033 ± 0.010 at the 90th, 75th, 50th, 25th, and 10th percentiles of the triglyceride distribution, respectively. Consistent with quantile-dependent expressivity, 11 drug studies report smaller genotype differences at lower (post-treatment) than higher (pre-treatment) triglyceride concentrations. This meant genotype-specific triglyceride changes could not move in parallel when triglycerides were decreased pharmacologically, so that subtracting pre-treatment from post-treatment triglyceride levels necessarily created a greater triglyceride decrease for the genotype with a higher pre-treatment value (purported precision-medicine genetic markers). In addition, sixty-five purported gene-environment interactions were found to be potentially attributable to triglyceride’s quantile-dependent expressivity, including gene-adiposity (APOA5, APOB, APOE, GCKR, IRS-1, LPL, MTHFR, PCSK9, PNPLA3, PPARγ2), gene-exercise (APOA1, APOA2, LPL), gene-diet (APOA5, APOE, INSIG2, LPL, MYB, NXPH1, PER2, TNFA), gene-alcohol (ALDH2, APOA5, APOC3, CETP, LPL), gene-smoking (APOC3, CYBA, LPL, USF1), gene-pregnancy (LPL), and gene-insulin resistance interactions (APOE, LPL).