Black hole entropy in 3D gravity with torsion

The role of torsion in quantum three-dimensional gravity is investigated by studying the partition function of the Euclidean theory in Riemann-Cartan spacetime. The entropy of the black hole with torsion is found to differ from the standard Bekenstein-Hawking result, but its form is in complete agreement with the first law of black hole thermodynamics.Comment: 17 pages, RevTeX, minor revision

In search of graduate attributes: A survey of six flagship programmes

The focus of this study is the emergence of distinctive graduate attributes in flagship programmes at Universities of Technology in South Africa. The theoretical framework chosen for this study, Legitimation Code Theory (Maton 2014), offers an explanation of the underlying knowledge principles that make different kinds of thinking, doing and being possible. This paper studies how favourable graduate attributes were achieved, identifies similarities across underpinning structures, and highlights the challenges faced by universities of technology in creating environments in which desired graduate attributes might be developed. The paper offers a means of understanding the potential for the emergence of graduate attributes across undergraduate programmes in vocational and professional higher education contexts

Observation of edge solitons in topological trimer arrays

We report the experimental observation of nonlinear light localization and edge soliton formation at the edges of fs-laser written trimer waveguide arrays, where transition from nontopological to topological phases is controlled by the spacing between neighboring trimers. We found that, in the former regime, edge solitons occur only above a considerable power threshold, whereas in the latter one they bifurcate from linear states. Edge solitons are observed in a broad power range where their propagation constant falls into one of the topological gaps of the system, while partial delocalization is observed when considerable nonlinearity drives the propagation constant into an allowed band, causing coupling with bulk modes. Our results provide direct experimental evidence of the coexistence and selective excitation in the same or in different topological gaps of two types of topological edge solitons with different internal structures, which can rarely be observed even in nontopological systems. This also constitutes the first experimental evidence of formation of topological solitons in a nonlinear system with more than one topological gap.The authors acknowledge funding of this study by RSF (grant 21‐12‐00096). Also, support by CEX2019‐000910‐S [funded by MCIN/AEI/10.13039/501100011033], Fundació Cellex, Fundació Mir‐Puig, and Generalitat de Catalunya (CERCA) is acknowledged.Peer ReviewedPostprint (author's final draft

Genome analysis reveals three distinct lineages of the cosmopolitan white shark

We thank Jarle Jørgensen for his support. We are grateful to Barry Bruce, Malcolm Francis, Clinton Duffy, and Andy Martin for provision of some additional samples. This project was funded by Nord University, Faculty of Biosciences and Aquaculture, Norway. The Norwegian Sequencing Centre, University of Oslo, Norway, which performed some of the DNA sequencing for this study, is supported by both the "Functional Genomics" and "Infrastructure" programs of the Research Council of Norway and the South-Eastern Norway Regional Health Authorities.Peer reviewe

Spatio-temporal genetic tagging of a cosmopolitan planktivorous shark provides insight to gene flow, temporal variation and site-specific re-encounters

Migratory movements in response to seasonal resources often influence population structure and dynamics. Yet in mobile marine predators, population genetic consequences of such repetitious behaviour remain inaccessible without comprehensive sampling strategies. Temporal genetic sampling of seasonally recurring aggregations of planktivorous basking sharks, Cetorhinus maximus, in the Northeast Atlantic (NEA) affords an opportunity to resolve individual re-encounters at key sites with population connectivity and patterns of relatedness. Genetic tagging (19 microsatellites) revealed 18% of re-sampled individuals in the NEA demonstrated inter/multi-annual site-specific re-encounters. High genetic connectivity and migration between aggregation sites indicate the Irish Sea as an important movement corridor, with a contemporary effective population estimate (Ne) of 382 (CI = 241–830). We contrast the prevailing view of high gene flow across oceanic regions with evidence of population structure within the NEA, with early-season sharks off southwest Ireland possibly representing genetically distinct migrants. Finally, we found basking sharks surfacing together in the NEA are on average more related than expected by chance, suggesting a genetic consequence of, or a potential mechanism maintaining, site-specific re-encounters. Long-term temporal genetic monitoring is paramount in determining future viability of cosmopolitan marine species, identifying genetic units for conservation management, and for understanding aggregation structure and dynamics

Observation of Pulsed Gamma-rays Above 25 GeV from the Crab Pulsar with MAGIC

One fundamental question about pulsars concerns the mechanism of their pulsed electromagnetic emission. Measuring the high-end region of a pulsar's spectrum would shed light on this question. By developing a new electronic trigger, we lowered the threshold of the Major Atmospheric gamma-ray Imaging Cherenkov (MAGIC) telescope to 25 GeV. In this configuration, we detected pulsed gamma-rays from the Crab pulsar that were greater than 25 GeV, revealing a relatively high cutoff energy in the phase-averaged spectrum. This indicates that the emission occurs far out in the magnetosphere, hence excluding the polar-cap scenario as a possible explanation of our measurement. The high cutoff energy also challenges the slot-gap scenario.Comment: Slight modification of the analysis: Fitting a more general function to the combined data set of COMPTEL, EGRET and MAGIC. Final result and conclusion is unchange

First bounds on the high-energy emission from isolated Wolf-Rayet binary systems

High-energy gamma-ray emission is theoretically expected to arise in tight binary star systems (with high mass loss and high velocity winds), although the evidence of this relationship has proven to be elusive so far. Here we present the first bounds on this putative emission from isolated Wolf-Rayet (WR) star binaries, WR 147 and WR 146, obtained from observations with the MAGIC telescope.Comment: (Authors are the MAGIC Collaboration.) Manuscript in press at The Astrophysical Journal Letter

Upper limit for gamma-ray emission above 140 GeV from the dwarf spheroidal galaxy Draco

The nearby dwarf spheroidal galaxy Draco with its high mass to light ratio is one of the most auspicious targets for indirect dark matter searches. Annihilation of hypothetical DM particles can result in high-energy gamma-rays, e.g. from neutralino annihilation in the supersymmetric framework. With the MAGIC telescope a search for a possible DM signal originating from Draco was performed during 2007. The analysis of the data results in a flux upper limit of 1.1x10^-11 photons cm^-2 sec^-1 for photon energies above 140 GeV, assuming a point like source. Furthermore, a comparison with predictions from supersymmetric models is given. While our results do not constrain the mSUGRA phase parameter space, a very high flux enhancement can be ruled out.Comment: Accepted for publication by Astrophysical Journa