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Emergence of high-mass stars in complex fiber networks (EMERGE) V. from filaments to spheroids : the origin of the hub-filament systems
Get PDFFunding: A.H., F.B., and A.S. received funding from the European Research Council (ERC) under the European Union’s Horizon 2020 research and innovation programme (Grant agreement no. 851435). D.S. acknowledges support of the Bonn-Cologne Graduate School, which is funded through the German Excellence Initiative as well as funding by the Deutsche Forschungs- gemeinschaft (DFG) via the Collaborative Research Center SFB 1601 “Habitats of massive stars across cosmic time” (subprojects B4 and B6). Furthermore, the project is receiving funding from the programme “Profilbildung 2020”, an initiative of the Ministry of Culture and Science of the State of Northrhine Westphalia. E.S. acknowledge financial support from European Research Council via the Horizon 2020 Framework Programme ERC Synergy “ECOGAL” Project GA-855130.Context . Identified as parsec-size, gas clumps at the junction of multiple filaments, hub-filament systems (HFS) play a crucial role during the formation of young clusters and high-mass stars. These HFS still appear to be detached from most galactic filaments when compared in the mass–length (M–L) phase space. Aims . We aim to characterize the early evolution of HFS as part of the filamentary description of the interstellar medium (ISM). Methods . Combining previous scaling relations with new analytic calculations, we created a toy model to explore the different physical regimes described by the M–L diagram. Despite its simplicity, our model accurately reproduces several observational properties reported for filaments and HFS, such as their expected typical aspect ratio (A), mean surface density (Σ), and gas accretion rate (ṁ). Moreover, this model naturally explains the different mass and length regimes populated by filaments and HFS, respectively. Results . Our model predicts a dichotomy between filamentary (A ≥ 3) and spheroidal (A < 3) structures connected to the relative importance of their fragmentation, accretion, and collapse timescales. Individual filaments with low accretion rates are dominated by an efficient internal fragmentation. In contrast, the formation of compact HFS at the intersection of filaments triggers a geometric phase-transition, leading to the gravitational collapse of these structures at parsec-scales in ~1–2 Myr. In addition, this process also induces higher accretion rates.Peer reviewe
Multi-dimensional oscillatory activity of mouse GnRH neurons in vivo
Get PDFThe gonadotropin-releasing hormone (GnRH) neurons represent the key output cells of the neural network controlling mammalian fertility. We used GCaMP fiber photometry to record the population activity of the GnRH neuron distal projections in the ventral arcuate nucleus where they merge before entering the median eminence to release GnRH into the portal vasculature. Recordings in freely behaving intact male and female mice revealed abrupt ~8 min duration increases in activity that correlated perfectly with the appearance of a subsequent pulse of luteinizing hormone (LH). The GnRH neuron dendrons also exhibited a low level of unchanging clustered, rapidly fluctuating baseline activity in males and throughout the estrous cycle in females. In female mice, a gradual increase in basal activity that exhibited ~80 min oscillations began in the afternoon of proestrus and lasted for 12 hr. This was associated with the onset of the LH surge that ended several hours before the fall in the GCaMP signal. Abrupt 8 min duration episodes of GCaMP activity continued to occur on top of the rising surge baseline before ceasing in estrus. These observations provide the first description of GnRH neuron activity in freely behaving animals. They demonstrate that three distinct patterns of oscillatory activity occur in GnRH neurons. These are comprised of low-level rapid baseline activity, abrupt 8 min duration oscillations that drive pulsatile gonadotropin secretion, and, in females, a gradual and very prolonged oscillating increase in activity responsible for the preovulatory LH surge.Peer reviewe
A qualitative synthesis of research into the use of exemplars in the English for Academic Purposes context to develop student feedback literacy
Get PDFIn recent years, feedback has been characterised by a student-centred paradigm with the learner playing a more active role. Arguably, this requires student feedback literacy (SFL), referring to a learner’s attitude towards and capability of understanding and using feedback to improve their work. Exemplar use has also been increasing and is viewed as a potential enabling activity for the enhancement of SFL. Research in these areas is flourishing within higher education but generally without demarcation between English for academic purposes (EAP) and content-focused courses. EAP classrooms could be considered unique domains, subject to specific learning outcomes and language or socio-cultural considerations. This systematic qualitative synthesis of 13 studies in an EAP context seeks to explore how exemplars are conceived and implemented, along with resultant affordances, limitations, and factors contributing to their usefulness. Findings indicate that as with higher education in general, exemplars are implemented with the aim of developing SFL. However, in the EAP context, a second application aimed at learners noticing interesting or useful features for the purposes of increasing linguistic resources or improving language or task-specific outcomes is identified. Exemplar use is also found to be impacted by language limitations and other factors which influence levels of engagement.Peer reviewe
Subjective interdependence and prosocial behaviour
Get PDFInterdependence describes the mutual control different individuals have over their own and others’ outcomes. Recent research suggests that interdependence is mentally represented along dimensions of mutual dependence, conflict (vs correspondence) of interests, and relative power. People construe interdependence from cues in their social environment, but subjective perceptions are also influenced by stable individual differences. Importantly, perceptions of interdependence are associated with prosocial behaviour. Perceived conflict of interests, in particular, is detrimental to prosociality, whereas mutual dependence can foster prosocial behaviour. Further, perceived conflict of interests and power may together shape cooperative outcomes. Future research may help elucidate the roots of cross-cultural differences in subjective interdependence and examine how formal and informal institutions promote prosocial behaviour by shifting our perceptions of interdependence.Peer reviewe
The Cooperation Databank : machine-readable science accelerates research synthesis
Get PDFPublishing studies using standardized, machine-readable formats will enable machines to perform meta-analyses on demand. To build a semantically enhanced technology that embodies these functions, we developed the Cooperation Databank (CoDa)—a databank that contains 2,636 studies on human cooperation (1958–2017) conducted in 78 societies involving 356,283 participants. Experts annotated these studies along 312 variables, including the quantitative results (13,959 effects). We designed an ontology that defines and relates concepts in cooperation research and that can represent the relationships between results of correlational and experimental studies. We have created a research platform that, given the data set, enables users to retrieve studies that test the relation of variables with cooperation, visualize these study results, and perform (a) meta-analyses, (b) metaregressions, (c) estimates of publication bias, and (d) statistical power analyses for future studies. We leveraged the data set with visualization tools that allow users to explore the ontology of concepts in cooperation research and to plot a citation network of the history of studies. CoDa offers a vision of how publishing studies in a machine-readable format can establish institutions and tools that improve scientific practices and knowledge.Peer reviewe
The maximality of T in Thompson's group V
Get PDFFunding: The fourth author was partially funded by NSF DMS-2005297.We show that R. Thompson’s group T is a maximal subgroup of the group V. The argument provides examples of foundational calculations which arise when expressing elements of V as products of transpositions of basic clopen sets in the Cantor space ℭ.Peer reviewe
The effect of exploratory trademark strategy on corporate cash holdings
Get PDFFunding: Ying Zou acknowledges the research grant from the Scientific Research Foundation of Hunan Education Department (No. 23B1098). Shufang Lai acknowledges the research grant from the National Natural Science Fund of China (No. 72002093).The theoretical and empirical focus of this study is the relationship between exploratory trademark strategy and corporate cash holdings, which is rarely explored in the literature. Using data from Chinese listed firms over the 2005–2021 period, we find a positive correlation between firms' exploratory trademark strategies and their cash holdings. Our cross-sectional analyses reveal that this effect is particularly strong in firms facing greater environmental uncertainty, higher financial constraints, and weaker corporate governance. We also find that exploratory trademark strategies drive increased investment in brand capital and R&D, with firms prioritizing strategic investments over cash dividends. These findings highlight the dual role of trademarks as both market assets and key elements of financial management, which prompt firms to maintain higher cash reserves to support their long-term strategic objectives.Peer reviewe
Magnetic fields in massive star-forming regions (MagMaR) : the magnetic field at the onset of high-mass star formation
Get PDFFunding: P.S. was partially supported by a Grant-in-Aid for Scientific Research (KAKENHI Number JP22H01271 and JP23H01221) of the Japan Society for the Promotion of Science (JSPS). P.C.C. was supported by the NAOJ Research Coordination Committee, NINS (NAOJ-RCC-2202-0401). The Green Bank Observatory is a facility of the National Science Foundation operated under cooperative agreement by Associated Universities, Inc. J.M.G. and P.S. acknowledge support by the grant PID2020-117710GB-I00 (MCI-AEI-FEDER, UE). This work is also partially supported by the program Unidad de Excelencia Maria de Maeztu CEX2020-001058-M. P.S. was partially supported by a Grant-in-Aid for Scientific Research (KAKENHI numbers JP22H01271 and JP24K17100) of JSPS. M.T.B. acknowledges financial support through the INAF Large Grant The role of MAGnetic fields in MAssive star formation (MAGMA). Y.C. was partially supported by a Grant-in-Aid for Scientific Research (KAKENHI number JP24K17103) of JSPS. X.L. acknowledges support from the National Key R&D Program of China (No. 2022YFA1603101), the Strategic Priority Research Program of the Chinese Academy of Sciences (CAS) Grant No. XDB0800300, the National Natural Science Foundation of China (NSFC) through grant Nos. 12273090 and 12322305, the Natural Science Foundation of Shanghai (No. 23ZR1482100), and the CAS "Light of West China" Program No. xbzg-zdsys-202212. C.J.C. acknowledges support from the STFC (grant ST/Y002229/1). K.P. is a Royal Society University Research Fellow, supported by grant No. URF\R1\211322. J.K. is supported by the Royal Society under grant No. RF\ERE\231132, as part of project URF\R1\211322. L.A.Z. acknowledges financial support from CONACyT-280775, UNAM-PAPIIT IN110618, and IN112323 grants, México. C.E. acknowledges the financial support from the grant RJF/2020/000071 as a part of the Ramanujan Fellowship awarded by the Science and Engineering Research Board (SERB). Data analysis was in part carried out on the Multi-wavelength Data Analysis System operated by the Astronomy Data Center (ADC), National Astronomical Observatory of Japan. This paper makes use of the following ALMA data: ADS/JAO.ALMA#2017.1.00101.S, ADS/JAO.ALMA#2018.1.00105.S, ADS/JAO.ALMA# 2016.1.01036.S, and ADS/JAO.ALMA#2017.1.00237.S. ALMA is a partnership of ESO (representing its member states), NSF (USA) and NINS (Japan), together with NRC (Canada), MOST and ASIAA (Taiwan), and KASI (Republic of Korea), in cooperation with the Republic of Chile. The Joint ALMA Observatory is operated by ESO, AUI/NRAO, and NAOJ.A complete understanding of the initial conditions of high-mass star formation and what processes determine multiplicity requires the study of the magnetic field in young massive cores. Using Atacama Large Millimeter/submillimeter Array (ALMA) 250 GHz polarization observations (0."3 = 1000 au) and ALMA 220 GHz high-angular-resolution observations (0."05 = 160 au), we have performed a full energy analysis including the magnetic field at core scales and have assessed what influences the multiplicity inside a massive core previously believed to be in the prestellar phase. With a mass of 31 M⊙, the G11.92 MM2 core has a young CS molecular outflow with a dynamical timescale of a few thousand years. At high resolution, the MM2 core fragments into a binary system, with a projected separation of 505 au and a binary mass ratio of 1.14. Using the Davis–Chandrasekhar–Fermi method with an angle dispersion function analysis, we estimate in this core a magnetic field strength of 6.2 mG and a mass-to-magnetic-flux ratio of 18. The MM2 core is strongly subvirialized, with a virial parameter of 0.064, including the magnetic field. The high mass-to-magnetic-flux ratio and low virial parameter indicate that this massive core is very likely undergoing runaway collapse, which is in direct contradiction with the core accretion model. The MM2 core is embedded in a filament that has a velocity gradient consistent with infall. In line with clump-fed scenarios, the core can grow in mass at a rate of 1.9–5.6 × 10−4 M⊙ yr−1. In spite of the magnetic field having only a minor contribution to the total energy budget at core scales (a few thousands of astronomical units), it likely plays a more important role at smaller scales (a few hundreds of astronomical units) by setting the binary properties. Considering energy ratios and a fragmentation criterion at the core scale, the binary system could have been formed by core fragmentation. The binary system properties (projected separation and mass ratio), however, are also consistent with radiation-magnetohydrodynamic simulations with super-Alfvenic or supersonic (or sonic) turbulence that form binaries by disk fragmentation.Peer reviewe
Investigation of the effect of solvation on 1J(Metal–P) spin–spin coupling
Get PDFFunding: Financial support from Slovak Grant Agencies VEGA and APVV (VEGA-2/0135/21, APVV-19-0516 and APVV-22-0488) is acknowledged. MB wishes to thank the EaStCHEM School of Chemistry for support and access to an HPC cluster maintained by Dr H. Früchtl.The solvent effect on the indirect 1J(M–P) spin–spin coupling constant in phosphine selenoether peri-substituted acenaphthene complexes LMCl2 is studied at the PP86 level of nonrelativistic and four-component relativistic density functional theory. Depending on the metal, the solvent effect can amount to as much as 50% or more of the total J-value. This explains the previously found disagreement between the 1J(Hg–P) coupling in LHgCl2, observed experimentally and calculated without considering solvent effects. To address the solvent effect, we have used polarizable continuum and microsolvated models. The solvent effect can be separated into indirect (structural changes) and direct (changes in the electronic structure). These effects are additive, each brings roughly about 50% of the total effect. For the in-depth analysis, we use a model with a lighter metal, Zn, instead of Hg. A much smaller solvent effect on 1J(Hg–P) for a dimer form of LHgCl2 is explained. Pilot calculations of 1J(M–P) couplings in analogous systems with other metals indicate that for metals preferring square planar structures the solvent effect is insignificant because these structures are fairly rigid. Tetrahedral structures are less constrained and can respond more easily to external effects such as solvation.Peer reviewe
Financial development and tax evasion : international evidence from OECD and non-OECD countries
Get PDFThis study investigates the nexus between financial development and tax evasion across 156 countries from 2000 to 2017. In contrast to previous research focusing solely on banks or financial markets’ development, we employ a more comprehensive financial development index introduced by the International Monetary Fund (IMF) in 2016. This index gauges the progress of financial institutions (FI) and financial markets (FM) in terms of depth, access, and efficiency. Our findings underscore a negative correlation between financial development and tax evasion. Enhanced depth, access, and efficiency in both FI and FM correspond to reduced levels of tax evasion. Nevertheless, disparities emerge between the Organization of Economic Cooperation and Development (OECD) and non-OECD countries. While non-OECD countries exhibit negative associations between FI and FM development and tax evasion, in OECD countries, the role of FI assumes greater significance in curtailing tax evasion. Notably, within OECD countries, the depth of FI and FM emerges as the sole influential factor. This contrasts starkly with non-OECD counterparts, where all dimensions − depth, access, and efficiency − negatively influence tax evasion. Our research has noteworthy implications for policymakers in both categories of countries.Peer reviewe
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