The electronic band structure and optical properties of boron arsenide

We compute the electronic band structure and optical properties of boron arsenide using the relativistic quasiparticle self-consistent $GW$ approach, including electron-hole interactions through solution of the Bethe-Salpeter equation. We also calculate its electronic and optical properties using standard and hybrid density functional theory. We demonstrate that the inclusion of self-consistency and vertex corrections provides substantial improvement in the calculated band features, in particular when comparing our results to previous calculations using the single-shot $GW$ approach and various DFT methods, from which a considerable scatter in the calculated indirect and direct band gaps has been observed. We find that BAs has an indirect gap of 1.674 eV and a direct gap of 3.990 eV, consistent with experiment and other comparable computational studies. Hybrid DFT reproduces the indirect gap well, but provides less accurate values for other band features, including spin-orbit splittings. Our computed Born effective charges and dielectric constants confirm the unusually covalent bonding characteristics of this III-V system.Comment: 7 pages, 3 figure

The barnacle and the building: a modern morality tale

A rare and almost complete barnacle fossil, previously described on the basis of two isolated shell fragments, was recently exposed in a limestone block on the outer wall of Melbourne's Old Magistrates' Courts in Victoria, Australia. These courts comprise one of the oldest and grandest buildings in Melbourne and because of this they have a heritage listing. As heritage-listed buildings are protected from alteration by law, and as removal of the fossil would be deemed "alteration", official permission had to be obtained to extract the specimen. This paper discusses the processes involved with extraction of a unique specimen from a protected building and provides an overview of the palaeontological significance of the fossil. Consideration is given to the likely fate of a fossil of this nature, situated a little below eye level on a busy city street, if it was left in situ; finally, the implications of designating a holotype from material removed from a building are assessed

Ovulaster protodecimae, n. sp. (Echinoidea, Spatangoida) and associated epifauna (Cirripedia, Verrucidae) from the Danian of Northeastern Italy

A new species of echinoid, Ovulaster protodecimae, is described from the Danian Scaglia Rosa Formation outcropping in the Venetian Prealps (Southern Alps, northeastern Italy). The new species belonging to the order Spatangoida, is very distinctive because of its inflated, almost triangular test, the high-positioned peri-proct and the plate arrangement on the oral face. This is the first report of teh genus Ovulaster in the Danian of Italy and the first description of an echinoid from the Early Palaeocene of Italy. One test has an epifauna of the sessile verrucid barnacle Verruca sp. cf. V. prisca Bosquet, 1854, attached on all except the oral surface

The ongoing evolution of humanness: perspectives from Darwin to de Chardin

The nature of humanness is discussed from observations made by Aristotle in 4th-century Greece, through to those of Charles Darwin, Teilhard de Chardin and William Shakespeare. Attempts to define humanness upon a narrow range of criteria, as some have tried, is argued as flawed, for humanness is more elusive than a single or a new demonstrated phenomena. The path that Darwin pursued in determining the place of humans in nature in his book The Descent of Man, and Selection in Relation to Sex is assessed from a 19th century perspective; the difficulties he faced, both personally and with the broader public, are reviewed and then evaluated in a modern context. Darwin's thesis adheres to scientific principles, and is debated, defended and later verified on these principles. This is somewhat at variance to the approach adopted by the priest-scientist de Chardin a century later in his major work, The Phenomenon of Man-in which an attempt is made to reconcile a deep Christian faith with science. De Chardin scores well from a theological viewpoint, but fails on scientific grounds as his thesis moves beyond the realms of empiricism into mysticism. Surprisingly, de Chardin's predicament of a future wherein human evolution enters a new stage of consciousness through the noosphere (an invisible layer of thought encompassing the globe) has been partially realised through the worldwide web, although the nature of the web is almost certainly not what de Chardin might have anticipated, or desired. Science too fails to answer all, particularly the nature of Go

A part, not apart from nature: The IUBS ethics commission - An overview of a journey from 2000-2012

This paper explores the development of the way in which humans interact and have interacted with their natural environment. In particular, it places this within the context of the International Union of Biological Science's Ethics Commission, a body established in 2007 to develop ethical norms for bioethics and environmental ethics. The Ethics Commission grew out of what was the IUBS Bioethics Committee - the name change being dictated by confusion about the meaning of the term bioethics - which had recently been captured by the medical profession and was increasingly applied to medical practice alone. The new IUBS Ethics Commission (ICE) had a public presence as the International Centre for Environmental and Bioethics (ICEB), the web page of which was a vehicle to facilitate the provision and dissemination of ideas, news, concerns and case studies about the ethical management of the biosphere. In July 2012, the commission ceased to exist as a stand-alone entity. The reasons for this closure were varied; ranging from a lack of interest, to a belief that the commission was no longer required, to an inability or a lack of willingness to be personally involved in environmental ethics. The ICE is nonetheless still an important part of IUBS - currently as a subcommittee within the Biological Education Commission. The paper finishes with a review of the achievements of the commission over the last few years, and assesses where the critical ethical issues in biological sciences are likely to arise in the next decade: continued environmental degradation, increased intellectual theft and scientific obfuscation

In pursuit of the biological imperative an intergenerational approach to biological justice

This paper analyses the relationships between ethics and biology - particularly within the context of the Earth's degrading biosphere. We assess the manner in which humans have valued, and should value past and future human generations - from rational perspectives and as consequence of natural justice. We argue that life on Earth is more than likely unique within the universe, and that as a consequence of this, there is a duty for humans to exercise greater environmental stewardship. On the basis of this, the moral obligations that we have to future generations and ultimately future environments are debated, then confirmed. We conclude with a new biological imperative, in which it is asserted that in nature, justice is inter-temporal and must embrace all life found in the Earth's biosphere

Creationism and intelligent design: a critique

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On the pedagogy of ethics in engineering degrees: rationale, imperatives and internationalization

Nations that are signatory to the Washington Accord (1989) accept that the teaching of ethics, in a professional context, is mandatory for undergraduate engineering curricula. The inclusion of ethics, in otherwise very tight curricula, is due to the changing role of engineering; in particular it reflects a greater public awareness of the effects of engineering processes. On the basis of this, it follows that engineers are required to demonstrate transparently responsible practice in the knowledge that they are indeed accountable for their actions. In most countries, this requirement is embodied in legislation. The teaching of ethics to engineering undergraduates is a relatively new concept. This paper provides an overview of one methodology, the 'full submergence' technique, wherein engineers are challenged to respond to ethical conundrums in a high intensity project-based, block course. Over the last decade, this model has been successfully used in four countries

Engineering needs environmental and global thinkers: a contextual analysis of student learning preferences

The need for engineering graduates who are environmentally and globally aware is now a recognised priority in professional practice. This paper presents an analysis of learning preferences of entry level students in a course which builds an early awareness of global environmental practice. The course on Engineering and the Environment started in 1991 as part of the undergraduate Environmental Engineering program at RMIT University. Subsequently the course was extended to Geological and then to Civil Engineering programs. The curriculum has paralleled the development of environmental practice in the professions of engineering and mining and provides a fundamental environmental context for students' subsequent learning in their programs and on-going professional practice. Curriculum development and some specific learning activities are briefly outlined. A challenge has been how to engage a diverse and increasingly large cohort of almost several hundred students in "non traditional" engineering lectures. A detailed analysis of student responses to a set of multiple choice exam questions has been conducted to test the hypothesis that various factors such as student choice of program may influence receptivity to different modes of learning and curriculum content. The study shows no significant difference between the various groups in regards to preference for evaluative type environmental learning, versus more traditional factual based engineering learning

Efficient and accurate approach to modeling the microstructure and defect properties of LaCoO3

Complex perovskite oxides are promising materials for cathode layers in solid oxide fuel cells. Such materials have intricate electronic, magnetic, and crystalline structures that prove challenging to model accurately. We analyze a wide range of standard density functional theory approaches to modeling a highly promising system, the perovskite LaCoO3, focusing on optimizing the Hubbard U parameter to treat the self-interaction of the B-site cation's d states, in order to determine the most appropriate method to study defect formation and the effect of spin on local structure. By calculating structural and electronic properties for different magnetic states we determine that U=4 eV for Co in LaCoO3 agrees best with available experiments. We demonstrate that the generalized gradient approximation (PBEsol+U) is most appropriate for studying structure versus spin state, while the local density approximation (LDA+U) is most appropriate for determining accurate energetics for defect properties