The progenitors of magnetic white dwarfs in open clusters

According to the fossil-field hypothesis magnetic fields are remnants of the previous stages of evolution. However, population synthesis calculations are unable to reproduce the magnetic white dwarf (MWD) sample without binary interaction or inclusion of a population of progenitor with unobservable small-scale fields. One necessary ingredient in population synthesis is the initial-to-final-mass relation (IFMR) which describes the mass-loss processes during the stellar evolution. When white dwarfs are members of open clusters, their evolutionary histories can be assessed through the use of cluster properties. In this work, we assess the cluster membership by correlating the proper-motion of MWDs with the cluster proper-motion and by analyzing the candidates spectroscopically with our magnetic model spectra in order to estimate the effective temperature and radii. We identified SDSS J085523.87+164059.0 to be a proper-motion member of Praesepe. We also included the data of the formerly identified cluster members NGC 6819-8, WD 0836+201 and estimated the mass, cooling age and the progenitor masses of the three probable MWD members of open clusters. According to our analysis, the newly identified cluster member SDSS J085523.87+164059.0 is an ultra-massive MWD of mass 1.12 $\pm$ 0.11 Msolar. We increase the sample of MWDs with known progenitor masses to ten, with the rest of the data coming from the common proper motion binaries. Our investigations show that, when effects of the magnetic fields are included in the diagnostics, the estimated properties of these cluster MWDs do not show evidence for deviations from the IFMR. Furthermore, we estimate the precision of the magnetic diagnostics which would be necessary to determine quantitatively whether magnetism has any effect on the mass-loss.Comment: 8 pages, 4 figures, accepted for publication in A&

Delivering manufacturing technology and workshop appreciation to engineering undergraduates using the flipped classroom approach

Delivery of manufacturing technology and practical workshop-based work, on undergraduate engineering courses that engage the learners, is challenging. The paper presents an experimental method of workshop delivery using the flipped learning approach, a pedagogical model in which the typical lecture and homework elements of a course are reversed. Video lectures are viewed by students prior to class. In-class time can be devoted to exercises, projects, or discussions as in this case. Learners were asked to observe three audiovisual clips in preparation for class. The objective was to determine whether the flipped classroom approach can enhance the learning experience, through better engagement with the students, compared to conventional classroom-based learning. The level of student participation and level of success have been established by means of feedback questionnaires from more than 100 participants and peer observation. The results are encouraging and demonstrate that this approach is favoured by the students

CVcat: an interactive database on cataclysmic variables

CVcat is a database that contains published data on cataclysmic variables and related objects. Unlike in the existing online sources, the users are allowed to add data to the catalogue. The concept of an ``open catalogue'' approach is reviewed together with the experience from one year of public usage of CVcat. New concepts to be included in the upcoming AstroCat framework and the next CVcat implementation are presented. CVcat can be found at http://www.cvcat.org.Comment: 5 pages A&A Latex, 4 figures, accepted for publication in A&

Analysis of the Hydrogen-rich Magnetic White Dwarfs in the SDSS

We have calculated optical spectra of hydrogen-rich (DA) white dwarfs with magnetic field strengths between 1 MG and 1000 MG for temperatures between 7000 K and 50000 K. Through a least-squares minimization scheme with an evolutionary algorithm, we have analyzed the spectra of 114 magnetic DAs from the SDSS (95 previously published plus 14 newly discovered within SDSS, and five discovered by SEGUE). Since we were limited to a single spectrum for each object we used only centered magnetic dipoles or dipoles which were shifted along the magnetic dipole axis. We also statistically investigated the distribution of magnetic-field strengths and geometries of our sample.Comment: to appear in the proceedings of the 16th European Workshop on White Dwarfs, Barcelona, 200

Sport in the city: measuring economic significance at the local level

In many cities throughout Europe, sport is increasingly being used as a tool for economic revitalisation. While there has been a growth in literature relating to the specific economic impacts of sports-led development, including professional sport facilities, teams, and sport events, limited research has been undertaken on the contribution of the whole sport sector to output and employment. In the United Kingdom (UK), studies have focused on evaluating sport-related economic activity at the national level, yet despite the increasing use of sport for local economic development little research has been undertaken at the city level. To address this situation, this article uses the National Income Accounting framework to measure the economic importance of sport in Sheffield, UK. It shows that the value-added in 1996/97 was 165.61m or 4.11% of Gross Domestic Product (GDP), approximately twice the amount predicted from current national estimates. It is argued that this can primarily be explained by previous studies under-estimating the economic importance of sport, largely due to methodological differences. It goes on to suggest that future research on the significance of sport should be undertaken at the local level to provide policymakers with information at the spatial level where regeneration programmes are being implemented.</p

Impact of temperature and mode polarization on the acoustic phonon range in complex crystalline phases: A case study on intermetallic clathrates

The low and weakly temperature-varying lattice thermal conductivity, κL (T), in crystals with a complex unit cell such as type-I clathrates is assumed to originate from a reduced momentum and energy space available for propagative lattice vibrations, which is caused by the occurrence of low-energy optical phonon modes. In the context of ab initio self-consistent phonon (SCP) theory, it has been shown that the cubic and quartic anharmonic interactions result in a temperature-induced energy renormalization of these low-lying optical branches which contributes to the anomalous behavior of κL (T) in structurally ordered type-I clathrates [T. Tadano and S. Tsuneyuki, Phys. Rev. Lett. 120, 105901 (2018)]. By means of inelastic neutron scattering, we provide evidence for this energy renormalization in temperature, which has been resolved for transversely and longitudinally polarized phonons in the single crystal type-I clathrate Ba7.81Ge40.67Au5.33. By mapping the neutron intensity in the momentum space, we demonstrate the coherent character of the low-lying optical phonons. The overall phonon spectrum and dynamical structure factors are satisfactorily reproduced by ab initio harmonic calculations using density functional theory with the meta-GGA SCAN functional and a fully ordered structure. However, a polarization-dependent cutoff energy with opposing temperature shifts for longitudinal and transverse acoustic dispersions is experimentally observed which is not reproduced by the simulations. Anharmonicity affects the energies of the low-lying optical phonons in the transverse polarization, which compares quantitatively well with available results from SCP theory, whereas differences are observed for the longitudinal polarizatio

The Far Side of Mars: Two Distant Marsquakes Detected by InSight

For over three Earth years the Marsquake Service has been analyzing the data sent back from the Seismic Experiment for Interior Structure¿the seismometer placed on the surface of Mars by NASA¿s InSight lander. Although by October 2021, the Mars seismic catalog included 951 events, until recently all these events have been assessed as lying within a radius of 100° of InSight. Here we report two distant events that occurred within days of each other, located on the far side of Mars, giving us our first glimpse into Mars¿ core shadow zone. The first event, recorded on 25 August 2021 (InSight sol 976), shows clear polarized arrivals that we interpret to be PP and SS phases at low frequencies and locates to Valles Marineris, 146° ± 7° from InSight. The second event, occurring on 18 September 2021 (sol 1000), has significantly more broadband energy with emergent PP and SS arrivals, and a weak phase arriving before PP that we interpret as Pdiff¿. Considering uncertain pick times and poorly constrained travel times for Pdiff¿, we estimate this event is at a distance between 107° and 147° from InSight. With magnitudes of MMaw 4.2 and 4.1, respectively, these are the largest seismic events recorded so far on Mars.Anna C. Horleston, Jessica C. E. Irving,and Nicholas A. Teanby are funded by the UKSA under Grant Numbers ST/R002096/1, ST/W002523/1, and ST/W002515/1.Nikolaj L. Dahmen, Cecilia Duran, Géraldine Zenhäusern, andSimon C. Stähler would like to acknowledge support from Eidgenössische Technische Hochschule (ETH) through the ETH+ funding scheme (ETH+02 19-1: “Planet Mars”). The French coauthors acknowledge the funding support provided by CNES and the Agence Nationale de la Recherche (ANR-19-CE31-0008-08 MAGIS) for SEIS operation and SEIS Science analysis. Alexander E. Stott acknowledges the French Space Agency CNES and ANR (ANR-19-CE31-0008-08). Caroline Beghein and Jiaqi Li were supported by NASA InSight Participating Scientist Program (PSP) Grant Number 80NSSC18K1679. This article is InSight Contribution Number 236

First Focal Mechanisms of Marsquakes

Since February 2019, NASA's InSight lander is recording seismic signals on the planet Mars, which, for the first time, allows to observe ongoing tectonic processes with geophysical methods. A number of Marsquakes have been located in the Cerberus Fossae graben system in Elysium Planitia and further west, in the Orcus Patera depression. We present a first study of the focal mechanisms of three well-recorded events (S0173a, S0183a, S0235b) to determine the processes dominating in the source region. We infer for all three events a predominantly extensional setting. Our method is adapted to the case of a single, multicomponent receiver and based on fitting waveforms of P and S waves against synthetic seismograms computed for the initial crustal velocity model derived by the InSight team. We explore the uncertainty due to the single-station limitation and find that even data recorded by one station constrains the mechanisms (reasonably) well. For the events in the Cerberus Fossae region (S0173a, S0235b) normal faulting with a relatively steep dipping fault plane is inferred, suggesting an extensional regime mainly oriented E-W to NE-SW. The fault regime in the Orcus Patera region is not determined uniquely because only the P wave can be used for the source inversion. However, we find that the P and weak S waves of the S0183a event show similar polarities to the event S0173, which indicates similar fault regimes

Tourists' consumption and interpretation of sport event imagery

In an era when popular and mass cultures are positioned further up the symbolic hierarchy, sport events are deemed by cities to be a valuable image or branding tools. Event strategies are often justified by their envisaged image effects and the celebrities, iconic structures and media exposure associated with sport events means that they are viewed as being particularly effective for this purpose. This paper evaluates the image effects of strategies deployed by three English cities; Birmingham, Manchester and Sheffield. Each of these cities has used a combination of regular sport fixtures, ‘mega’ sport events and event bids to further their reputations as tourist destinations. Semi-structured interviews with a representative sample of potential tourists were used to provide evidence of the impacts of these initiatives. Despite some participants making connections with traffic chaos and violence, in general sport events appear to have encouraged positive connotations amongst potential tourists, including modernity, progress and vitality. Events seem to be regarded favourably at a cultural level, generating widespread positive meanings even when individual preferences vary. This has positive implications for cities deploying sport events as re-imaging or branding tools