A GPU-Accelerated Mid-Fidelity Aerodynamic and Aeroacoustic Simulation Framework

A new solver based on the Vortex Lattice Method (VLM), 3D panel method and the Vortex Particle Method (VPM) has been presented that aims to provide a computationally efficient method to predict the aerodynamics and aeroacoustics of complex vehicle configurations. The solver uses just-in-time compilation techniques and GPU hardware acceleration to ensure time to solution is kept as small as possible. The solver was compared to experimental results for an isolated propeller and edgewise propeller, showing good agreement to experimental data. The aeroacoustic solver is based on Farassat's formulation 1A (F1A) of the Ffwocs Williams and Hawkings Equation, which has been implemented in the same framework as the aerodynamic part of the solver

For a Migrant Art: Samuel Beckett and Cultural Nationalism

This essay charts Samuel Beckett’s linguistic migration from English to French at the end of the Second World War, locating this within the context of other twentieth-century literary migrations. It then proceeds to identify some of the principal ways in which Beckett seeks to resist forms of cultural nationalism (Irish, French and German). The distance that Beckett takes from these European forms of cultural nationalism is reflected not only in the migrant status of his characters, but also in the way in which he deploys national-cultural references. The essay argues that Beckett’s aim in this respect bears comparison with that of the ‘good European’ as defined by Nietzsche. An important difference, however, is that in Beckett’s case the emphasis falls not upon cosmopolitanism but rather upon a perpetual migrancy that is captured above all in his movement between languages

Diaphus taaningi Norman, the principal component of a shallow sound-scattering layer in the Cariaco Trench, Venezuela

A myctophid fish, Diaphus taaningi Norman, is the principal component of a distinct daytime sound-scattering layer lying near 250 m, well above the anoxic, hydrogen-sulfide zone of the Cariaco Trench. The scattering layer produced strong sonar echoes at 12, 25, and 50 kHz; mean sound-scattering strength at layer depth at 25 kHz was approximately --73 dB and at 50 kHz was approximately --67 dB...

Extracellular redox cycling and hydroxyl radical production occurs widely in lichenized Ascomycetes

© 2017 British Mycological SocietySome free-living Ascomycetes and white and brown rot Basidiomycetes can generate hydroxyl radicals using extracellular redox cycling. However, the mechanisms of hydroxyl radical production differ between white and brown rot Basidiomycetes, and are unknown for Ascomycetes. Here, we present a survey of extracellular hydroxyl radical production by a range of lichenized Ascomycetes. Results show that given a quinone and chelated ferric ions, many lichens can readily produce hydroxyl radicals, and this is accompanied by the reduction of Fe3+ to Fe2+. In white rot fungi, extracellular redox enzymes have been proposed to be involved in hydroxyl radical generation. However, a survey of a wide range of lichens suggests that in these fungi hydroxyl radical production does not directly correlate with the activity of laccases and peroxidases. Rather, radicals are probably produced by a mechanism like that proposed for brown rot fungi. Potential roles of hydroxyl radicals produced by lichens include the breakdown of lignocellulosic residues in the soil which may allow lichens to live a partially saprotrophic existence, the breakdown of toxic soil chemicals and the formation of an ‘oxidative burst’ to deter potential pathogens

Population history from the Neolithic to present on the Mediterranean island of Sardinia: an ancient DNA perspective

Recent ancient DNA studies of western Eurasia have revealed a dynamic history of admixture, with evidence for major migrations during the Neolithic and Bronze Age. The population of the Mediterranean island of Sardinia has been notable in these studies –} Neolithic individuals from mainland Europe cluster more closely with Sardinian individuals than with all other present-day Europeans. The current model to explain this result is that Sardinia received an initial influx of Neolithic ancestry and then remained relatively isolated from expansions in the later Neolithic and Bronze Age that took place in continental Europe. To test this model, we generated genome-wide capture data (approximately 1.2 million variants) for 43 ancient Sardinian individuals spanning the Neolithic through the Bronze Age, including individuals from Sardinia{’}s Nuragic culture, which is known for the construction of numerous large stone towers throughout the island. We analyze these new samples in the context of previously generated genome-wide ancient DNA data from 972 ancient individuals across western Eurasia and whole-genome sequence data from approximately 1,500 modern individuals from Sardinia. The ancient Sardinian individuals show a strong affinity to western Mediterranean Neolithic populations and we infer a high degree of genetic continuity on the island from the Neolithic (around fifth millennium BCE) through the Nuragic period (second millennium BCE). In particular, during the Bronze Age in Sardinia, we do not find significant levels of the {“}Steppe{” ancestry that was spreading in many other parts of Europe at that time. We also characterize subsequent genetic influx between the Nuragic period and the present. We detect novel, modest signals of admixture between 1,000 BCE and present-day, from ancestry sources in the eastern and northern Mediterranean. Within Sardinia, we confirm that populations from the more geographically isolated mountainous provinces have experienced elevated levels of genetic drift and that northern and southwestern regions of the island received more gene flow from outside Sardinia. Overall, our genetic analysis sheds new light on the origin of Neolithic settlement on Sardinia, reinforces models of genetic continuity on the island, and provides enhanced power to detect post-Bronze-Age gene flow. Together, these findings offer a refined demographic model for future medical genetic studies in Sardinia