Open-ended evolution to discover analogue circuits for beyond conventional applications

This is the author's accepted manuscript. The final publication is available at Springer via http://dx.doi.org/10.1007/s10710-012-9163-8. Copyright @ Springer 2012.Analogue circuits synthesised by means of open-ended evolutionary algorithms often have unconventional designs. However, these circuits are typically highly compact, and the general nature of the evolutionary search methodology allows such designs to be used in many applications. Previous work on the evolutionary design of analogue circuits has focused on circuits that lie well within analogue application domain. In contrast, our paper considers the evolution of analogue circuits that are usually synthesised in digital logic. We have developed four computational circuits, two voltage distributor circuits and a time interval metre circuit. The approach, despite its simplicity, succeeds over the design tasks owing to the employment of substructure reuse and incremental evolution. Our findings expand the range of applications that are considered suitable for evolutionary electronics

Strategies and tensions in communicating research on sexual and reproductive health, HIV and AIDS: a qualitative study of the experiences of researchers and communications staff

<p>Abstract</p> <p>Background</p> <p>Sexual and Reproductive Health (SRH) and HIV issues are often controversial and neglected, leading to challenges with engaging policy actors. Research evidence is complex, posing further challenges for ensuring that policy and practice are evidence-based. Many health researchers are adopting innovative approaches to engaging stakeholders in their research, yet these experiences are not often shared. This qualitative study focuses on the research communication and policy influencing objectives, strategies and experiences of four research consortia working on SRH, HIV and AIDS.</p> <p>Methods</p> <p>We carried out 22 in-depth interviews with researchers and communications specialists (research actors) from the four consortia and their partners, working in nine countries in sub-Saharan Africa and Asia. Using the ‘framework’ approach to qualitative data analysis, we identified factors that affect the interaction of research evidence with policy and practice. We used the ODI RAPID analytical framework to present these results, adapting this tool by incorporating the actions, strategies and positionality of research actors.</p> <p>Results</p> <p>The characteristics of researchers and their institutions, policy context, the multiplicity of actors, and the nature of the research evidence all play a role in policy influencing processes. Research actors perceived a trend towards increasingly intensive and varied communication approaches. Effective influencing strategies include making strategic alliances and coalitions and framing research evidence in ways that are most attractive to particular policy audiences. Tensions include the need to identify and avoid unnecessary communication or unintended impacts, challenges in assessing and attributing impact and the need for adequate resources and skills for communications work.</p> <p>Conclusions</p> <p>We contend that the adapted RAPID framework can serve as a tool for research actors to use in resolving these tensions, through facilitating a reflexive approach to considering their own combination of attributes, skills, networks and objectives and the ways these relate to policy contexts, actors and processes.</p

Perception of Vibrotactile Cues in Musical Performance

We suggest that studies on active touch psychophysics are needed to inform the design of haptic musical interfaces and better understand the relevance of haptic cues in musical performance. Following a review of the previous literature on vibrotactile perception in musical performance, two recent experiments are reported. The first experiment investigated how active finger-pressing forces affect vibration perception, finding significant effects of vibration type and force level on perceptual thresholds. Moreover, the measured thresholds were considerably lower than those reported in the literature, possibly due to the concurrent effect of large (unconstrained) finger contact areas, active pressing forces, and long-duration stimuli. The second experiment assessed the validity of these findings in a real musical context by studying the detection of vibrotactile cues at the keyboard of a grand and an upright piano. Sensitivity to key vibrations in fact not only was highest at the lower octaves and gradually decreased toward higher pitches; it was also significant for stimuli having spectral peaks of acceleration similar to those of the first experiment, i.e., below the standard sensitivity thresholds measured for sinusoidal vibrations under passive touch conditions

The V471A polymorphism in autophagy-related gene ATG7 modifies age at onset specifically in Italian Huntington disease patients

The cause of Huntington disease (HD) is a polyglutamine repeat expansion of more than 36 units in the huntingtin protein, which is inversely correlated with the age at onset of the disease. However, additional genetic factors are believed to modify the course and the age at onset of HD. Recently, we identified the V471A polymorphism in the autophagy-related gene ATG7, a key component of the autophagy pathway that plays an important role in HD pathogenesis, to be associated with the age at onset in a large group of European Huntington disease patients. To confirm this association in a second independent patient cohort, we analysed the ATG7 V471A polymorphism in additional 1,464 European HD patients of the “REGISTRY” cohort from the European Huntington Disease Network (EHDN). In the entire REGISTRY cohort we could not confirm a modifying effect of the ATG7 V471A polymorphism. However, analysing a modifying effect of ATG7 in these REGISTRY patients and in patients of our previous HD cohort according to their ethnic origin, we identified a significant effect of the ATG7 V471A polymorphism on the HD age at onset only in the Italian population (327 patients). In these Italian patients, the polymorphism is associated with a 6-years earlier disease onset and thus seems to have an aggravating effect. We could specify the role of ATG7 as a genetic modifier for HD particularly in the Italian population. This result affirms the modifying influence of the autophagic pathway on the course of HD, but also suggests population-specific modifying mechanisms in HD pathogenesis

Automated Design of Both the Topology and Sizing of Analog Electrical Circuits Using Genetic Programming

: This paper describes an automated process for designing analog electrical circuits based on the principles of natural selection, sexual recombination, and developmental biology. The design process starts with the random creation of a large population of program trees composed of circuit-constructing functions. Each program tree specifies the steps by which a fully developed circuit is to be progressively developed from a common embryonic circuit appropriate for the type of circuit that the user wishes to design. Each fully developed circuit is translated into a netlist, simulated using a modified version of SPICE, and evaluated as to how well it satisfies the user&apos;s design requirements. The fitness measure is a user-written computer program that may incorporate any calculable characteristic or combination of characteristics of the circuit, including the circuit&apos;s behavior in the time domain, its behavior in the frequency domain, its power consumption, the number of components, cost o..