Rendering Grass Blowing in the Wind with Global Illumination

We have simulated a time varying wind field using the lattice Boltzmann model, and its effect on blades of grass with a simple mass-spring model. We present a global illumination model for multiple scattering of incident sun and sky illumination within the field of grass. We model the grass as a continuous distribution of infinitesimal colored scattering flakes and solve a system of differential equations for the radiance transport. We repeat this for a collection of grass bending directions and amounts, an...     

Preface from Guest Editor

Max Lu has been serving as Deputy Vice-Chancellor and Vice President (Research) since 2009 at the University of Queensland,Australia.He was also the Foundation Director of the ARC Centre of Excellence for Functional Nanomaterials from 2003 to 2009. Professor Lu's research expertise is in the areas of materials chemistry and nanotechnology.He is known for his work on nanoparticles and nanoporous materials for clean energy and environmental technologies.With over 500 journal publications in high impact journals including Nature,Journal of the American Chemical Society,Angewandte Chemie,and Advanced Materials;he is also co-inventor of 20 international patents.Professor Lu is an Institute for Scientific Information (ISI) Highly Cited Author in Materials Science with over 17,500 citations (h-index of 63).He has received numerous prestigious awards nationally and internationally including the Chinese Academy of Sciences International Cooperation Award,China International Science and Technology Cooperation Award,Orica Award,RK Murphy Medal,Le Fevre Prize,ExxonMobil Award,Chemeca Medal (2011),and Top 100 Most Influential Engineers in Australia (2004,2010,2012).He is an elected Fellow of ATSE and Fellow of Institution of Chemical Engineers (IChemE).He is an editor and editorial board member of 12 major international journals including Colloid and Interface Science and Carbon.     

Single mimivirus particles intercepted and imaged with an X-ray laser

X-ray lasers offer new capabilities in understanding the structure of biological systems, complex materials and matter under extreme conditions. Very short and extremely bright, coherent X-ray pulses can be used to outrun key damage processes and obtain a single diffraction pattern from a large macromolecule, a virus or a cell before the sample explodes and turns into plasma. The continuous diffraction pattern of non-crystalline objects permits oversampling and direct phase retrieval. Here we show that high-quality diffraction data can be obtained with a single X-ray pulse from a non-crystalline biological sample, a single mimivirus particle, which was injected into the pulsed beam of a hard-X-ray free-electron laser, the Linac Coherent Light Source. Calculations indicate that the energy deposited into the virus by the pulse heated the particle to over 100,000?K after the pulse had left the sample. The reconstructed exit wavefront (image) yielded 32-nm full-period resolution in a single exposure and showed no measurable damage. The reconstruction indicates inhomogeneous arrangement of dense material inside the virion. We expect that significantly higher resolutions will be achieved in such experiments with shorter and brighter photon pulses focused to a smaller area. The resolution in such experiments can be further extended for samples available in multiple identical copies.     

Revision of the type species of Metroperiella (Bryozoa,Cheilostomatida), with the description of two new species

We here fix the types of Schizoporella lepralioides Calvet in Jullien and Calvet, type species of the genus Metroperiella Canu & Bassler, and redescribe the species based on scanning electron microscope examination. Metroperiella populations from the Mediterranean Sea, which have hitherto been regarded as conspecific with Metroperiella lepralioides, are introduced as a new species, Metroperiella mesogeia sp. nov. Accordingly, the geographic distribution of M. lepralioides is restricted to its type locality, the Azores Archipelago (central North Atlantic). Another species, Metroperiella porellidesia sp. nov., which occurs sympatrically with M. lepralioides, is also newly described.

urn:lsid:zoobank.org:pub:523EA5DE-B023-48ED-8D85-37CAF5475164     

Erythropoietin modulates the neural control of hypoxic ventilation

Numerous factors involved in general homeostasis are able to modulate ventilation. Classically, this comprises several kind of molecules, including neurotransmitters and steroids that are necessary for fine tuning ventilation under different conditions such as sleep, exercise, and acclimatization to high altitude. Recently, however, we have found that erythropoietin (Epo), the main regulator of red blood cell production, influences both central (brainstem) and peripheral (carotid bodies) respiratory centers when the organism is exposed to hypoxic conditions. Here, we summarize the effect of Epo on the respiratory control in mammals and highlight the potential implication of Epo in the ventilatory acclimatization to high altitude, as well as in the several respiratory sickness and syndromes occurring at low and high altitude. (Part of a multi-author review.)     

Variations in earthquake-size distribution across different stress regimes

The earthquake size distribution follows, in most instances, a power law, with the slope of this power law, the 'b value', commonly used to describe the relative occurrence of large and small events (a high b value indicates a larger proportion of small earthquakes, and vice versa). Statistically significant variations of b values have been measured in laboratory experiments, mines and various tectonic regimes such as subducting slabs, near magma chambers, along fault zones and in aftershock zones. However, it has remained uncertain whether these differences are due to differing stress regimes, as it was questionable that samples in small volumes (such as in laboratory specimens, mines and the shallow Earth's crust) are representative of earthquakes in general. Given the lack of physical understanding of these differences, the observation that b values approach the constant 1 if large volumes are sampled was interpreted to indicate that b = 1 is a universal constant for earthquakes in general. Here we show that the b value varies systematically for different styles of faulting. We find that normal faulting events have the highest b values, thrust events the lowest and strike-slip events intermediate values. Given that thrust faults tend to be under higher stress than normal faults we infer that the b value acts as a stress meter that depends inversely on differential stress.