2,738 research outputs found
Analysing co-evolution among artificial 3D creatures
This paper is concerned with the analysis of coevolutionary dynamics among 3D artificial creatures, similar to those introduced by Sims (1). Coevolution is subject to complex dynamics which are notoriously difficult to analyse. We introduce an improved analysis method based on Master Tournament matrices [2], which we argue is both less costly to compute and more informative than the original method. Based on visible features of the resulting graphs, we can identify particular trends and incidents in the dynamics of coevolution and look for their causes. Finally, considering that coevolutionary progress is not necessarily identical to global overall progress, we extend this analysis by cross-validating individuals from different evolutionary runs, which we argue is more appropriate than single-record analysis method for evaluating the global performance of individuals
Is research ethics committee approval necessary for publication of prospective surgical research studies?
Report on ARGOS' second qualitative interview
The primary objective of the ARGOS project is the transdisciplinary examination of the
condition of sustainable agriculture in New Zealand (including environmental, economic and social aspects). In pursuit of this objective to date, considerable effort has been dedicated to assessing the comparative sustainability or resilience of designated management panels in three branches of the New Zealand agricultural sector (dairy, kiwifruit and sheep/beef). For this purpose, farms of comparable size and similar location were assigned panel membership as determined by an individual farmerās compliance (or lack thereof) with existing market audit schemes which ā to varying degrees ā regulate farm management practice. By sector, the panels are comprised of conventional and organic methods of dairy
farming, integrated pest management (Hayward, green, and Hort 16a, gold) and organic (Hayward) methods of kiwifruit production, and conventional, integrated and organic methods of sheep and beef farming. Due to the distinct nature of practices associated with each panel, differences in the assessed ecological, economic and social features of the participating farms and farm households offer the potential to distinguish the relative sustainability of systems based on these practices
How do the blind āseeā? The role of spontaneous brain activity in self-generated perception
Spontaneous activity of the human brain has been well documented, but little is known about the functional role of this ubiquitous neural phenomenon. It has previously been hypothesized that spontaneous brain activity underlies unprompted (internally generated) behaviour. We tested whether spontaneous brain activity might underlie internally-generated vision by studying the cortical visual system of five blind/visually-impaired individuals who experience vivid visual hallucinations (Charles Bonnet syndrome). Neural populations in the visual system of these individuals are deprived of external input, which may lead to their hyper-sensitization to spontaneous activity fluctuations. To test whether these spontaneous fluctuations can subserve visual hallucinations, the functional MRI brain activity of participants with Charles Bonnet syndrome obtained while they reported their hallucinations (spontaneous internally-generated vision) was compared to the: (i) brain activity evoked by veridical vision (externally-triggered vision) in sighted controls who were presented with a visual simulation of the hallucinatory streams; and (ii) brain activity of non-hallucinating blind controls during visual imagery (cued internally-generated vision). All conditions showed activity spanning large portions of the visual system. However, only the hallucination condition in the Charles Bonnet syndrome participants demonstrated unique temporal dynamics, characterized by a slow build-up of neural activity prior to the reported onset of hallucinations. This build-up was most pronounced in early visual cortex and then decayed along the visual hierarchy. These results suggest that, in the absence of external visual input, a build-up of spontaneous fluctuations in early visual cortex may activate the visual hierarchy, thereby triggering the experience of vision
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