Regularizing the quark-level σ\sigma model

We show that the finite difference, $-i\pi^2 m^2$, between quadratic and logarithmic divergent integrals $\int d^4p[m^2(p^2-m^2)^{-2}-(p^2-m^2)^{-1}]$, as encountered in the linear $\sigma$ model, is in fact regularization independent.Comment: 9 pages, 2 figures, Latex, to appear in Mod. Phys. Lett.

Seismic imaging at the cross-roads: Active, passive, exploration and solid Earth

Science has grown from our need to understand the world around us. Seismology is no different, with earthquakes and their destructive effect on society providing the motivation to understand the Earth's seismic wavefield. The question of when seismology as a science really began is an interesting one, but it is unlikely that there will ever be a universally agreed-upon date, partly because of the incompleteness of the historical record, and partly because the definition of what constitutes science varies from person to person. For instance, one could regard 1889 as the true birth of seismology, because that is when the first distant earthquake was detected by an instrument; in this case Ernst von Rebeur-Paschwitz detected an earthquake in Japan using a pendulum in Potsdam, Germany (Ben-Menahem, 1995). However, even the birth of instrumental seismology could be contested; the so-called Zhang Heng directional “seismoscope” (detects ground motion but not as a function of time) was invented in 132 CE (Rui and Yan-xiang, 2006), and is said to have detected a four-hundred mile distant earthquake which was not felt at the location of the instrument Needham, 1959, Dewey and Byerly, 1969. Prior to instrumental seismology, observations of earthquakes were not uncommon; for instance, Aristotle provided a classification of earthquakes based on the nature of observed ground motion (Ben-Menahem, 1995)

Cost optimization of offshore wind farm combination with reversible solid oxide cell system producing hydrogen using the PyPSA power system modelling tool

In the context of reaching the net zero carbon target, the UK has set an ambitious target of having a green hydrogen production capacity of 5 GW by 2030. As part of the EPSRC-funded project on high efficiency reversible solid oxide cells (rSOC) for the integration of offshore renewable energy (ORE) using hydrogen, eight scenarios where hydrogen is combined with offshore renewable energy were identified. A model using the PyPSA power system modelling tool combined with a sensitivity study, investigated optimized rSOC system capacities, hydrogen storage capacities, and subsea cable connection capacities under various combinations of infrastructure cost, rSOC system efficiencies, and electricity prices for one of the scenarios. Preliminary results for a 600 MW wind farm situated 60 km from shore combined with offshore hydrogen production illustrate the impact of electricity price on decision-making in energy dispatch and on optimization of infrastructure of an ORE-rSOC system. Results indicate that high electricity price fluctuations call for large amounts of hydrogen production and storage capacity. Further refinement of input data would make this approach a promising decision-making tool for the use in the design of an ORE-rSOC system

Inherited crustal deformation along the East Gondwana margin revealed by seismic anisotropy tomography

Acknowledgments We thank Mallory Young for providing phase velocity measurements in mainland Australia and Tasmania. Robert Musgrave is thanked for making available his tilt-filtered magnetic intensity map. In the short term, data may be made available by contacting the authors (S.P. or N.R.). A new database of passive seismic data recorded in Australia is planned as part of a national geophysics data facility for easy access download. Details on the status of this database may be obtained from the authors (S.P., N.R., or A.M.R.). There are no restrictions on access for noncommercial use. Commercial users should seek written permission from the authors (S.P. or N.R.). Ross Cayley publishes with the permission of the Director of the Geological Survey of Victoria.Peer reviewedPublisher PD

Evidence of micro-continent entrainment during crustal accretion

Peer reviewedPublisher PD

Development of a Novel Bioactive Functionally Guided Tissue Graded Membrane for Periodontal Lesions

Periodontal disorders are chronic inflammatory condition of the supporting structures of the tooth. Guided tissue regeneration (GTR) membranes have been used in the management of destructive forms of periodontal disease as a means of aiding regeneration of lost supporting tissues, such as alveolar bone, cementum, gingiva and periodontal ligament. In this study, individual layers of a functionally graded bioactive composite membrane were fabricated using the techniques of solvent casting, freeze gelation and electrospinning by incorporating Hydroxyapatite (HA) alongside Chitosan and using acetic acid as the primary solvent. The techniques were simple, time /energy efficient and reproducible resulting in novel non porous and porous scaffolds with potential for use in periodontal tissue regeneration. Scaffolds were characterised in terms of ultra structure morphology by scanning electron microscopy, physiochemical properties, water uptake, and degradation by weight loss, mechanical properties and biocompatibility. Microscopy revealed porous features and presence of hydroxyapatite was confirmed with Fourier Transform Infrared (FTIR) spectroscopy. Morphology of the pores varied with different solvents, which were affected by addition of HA. Biocompatibility studies were carried out using a human osteosarcoma cell line and human embryonic stem cell-derived mesenchymal progenitor cells. All tested scaffolds showed increasing cell viability over the tested culture period. In conclusion, solvent casting, freeze gelation and electrospinning were successfully used to fabricate scaffolds with different morphology and porosity. Future work will focus on incorporation of drug into the core layer and combining the surface and core layers to form a spatially designed functionally graded biodegradable membrane with the potential of being used for periodontal tissue regeneration

Attitudes Toward Business Ethics And Degree Of Opinion Leadership Of Future Managers In The United States, Finland, And China

The purpose of this study was to compare the attitudes towards business ethics of future managers in three countries: the United State, Finland, and China, and determine whether business ethics attitudes differed by the students major, class year, GPA, gender, age, and the number of ethics and religious studies courses completed. Additionally the relationship between the degree of opinion leadership and ethical attitudes was examined to determine if opinion leaders exhibited different attitudes towards business ethics

Seismic signature of subduction termination from teleseismic P- and S-wave arrival-time tomography : the case of northern Borneo

Acknowledgments S.P. acknowledges support from the Natural Environmental Research Council (NERC) Grant NE/R013500/1 and from the European Union's Horizon 2020 Research and Innovation Program under Marie Skłodowska-Curie Grant Agreement 790203. We thank the TanDEM-X Science Communication Team (German Aerospace Center (DLR) e.V.) for providing TanDEM topographic data. We thank the NERC Geophysical Equipment Facility for loan 1038 and seismometers loaned by the University of Cambridge and Aberdeen. We would like to thank Zhong-Hai Li and an anonymous reviewer for their constructive feedback during the review process.Peer reviewedPostprin