Genetic instability in cyanobacteria - an elephant in the room?

Many research groups are interested in engineering the metabolism of cyanobacteria with the objective to convert solar energy, CO2, and water (perhaps also N2) into commercially valuable products. Toward this objective, many challenges stand in the way before sustainable production can be realized. One of these challenges, potentially, is genetic instability. Although only a handful of reports of this phenomenon are available in the scientific literature, it does appear to be a real issue that so far has not been studied much in cyanobacteria. With this brief perspective, I wish to raise the awareness of this potential issue and hope to inspire future studies on the topic as I believe it will make an important contribution to enabling sustainable large-scale biotechnology in the future using aquatic photobiological microorganisms

Strain and temperature sensors using multimode optical fiber Bragg gratings and correlation signal processing

Multimode fiber optic Bragg grating sensors for strain and temperature measurements using correlation signal processing methods have been developed. Two multimode Bragg grating sensors were fabricated in 62/125 m graded-index silica multimode fiber; the first sensor was produced by the holographic method and the second sensor by the phase mask technique. The sensors have signal reflectivity of approximately 35% at peak wavelengths of 835 nm and 859 nm, respectively. Strain testing of both sensors has been done from 0 to 1000 με and the temperature testing from 40 to 80°C. Strain and temperature sensitivity values are 0.55 pm/με and 6 pm/°C, respectively. The sensors are being applied in a power-by-light hydraulic valve monitoring system

Trauma and dramatherapy: dreams, play and the social construction of culture

The article explores the ways in which the therapeutic potentials of drama can connect to individuals and groups who have experienced ‘trauma’. Three questions are used to structure the enquiry: Are dreams and dramatherapy related to trauma, and if so how? Can we see trauma as socially constructed? Can play help to resolve people’s experiences of trauma? First the relationship between dreams and dramatherapy is discussed as a way of illuminating some of the processes which can occur in work involving those who have experienced trauma. This is followed by a review of the relationships between the concept that trauma is socially constructed and dramatherapy. The third section explores how play features in dramatherapy’s engagement with clients who have experienced trauma. A case example of Abui, a child refugee from Sierra Leone, is examined from the perspective of the three questions

Cofactor engineering for enhancing the flux of metabolic pathways.

The manufacture of a diverse array of chemicals is now possible with biologically engineered strains, an approach that is greatly facilitated by the emergence of synthetic biology. This is principally achieved through pathway engineering in which enzyme activities are coordinated within a genetically amenable host to generate the product of interest. A great deal of attention is typically given to the quantitative levels of the enzymes with little regard to their overall qualitative states. This highly constrained approach fails to consider other factors that may be necessary for enzyme functionality. In particular, enzymes with physically bound cofactors, otherwise known as holoenzymes, require careful evaluation. Herein, we discuss the importance of cofactors for biocatalytic processes and show with empirical examples why the synthesis and integration of cofactors for the formation of holoenzymes warrant a great deal of attention within the context of pathway engineering

Estimating preferences for different types of pedestrian crossing facilities

This paper reports the results of a study to understand the preferences of pedestrians towards using different types of road crossing facilities. A preliminary qualitative study found that people’s perceptions about crossing facilities are shaped by aspects such as safety, convenience, crossing time, accessibility, and personal security. The main quantitative study consisted of a stated preference survey implemented in three neighbourhoods in English cities near busy roads. Participants were first asked to indicate how comfortable they felt using different types of crossing facilities. Footbridges and underpasses were systematically rated below signalised crossings. Participants were then asked to choose between walking different additional times to use certain types of crossing facility or avoid crossing the road altogether. The analysis of the choices using a mixed logit model found that on average participants are willing to walk an additional 2.4 and 5.3 minutes to use a straight signalised crossing and avoid using footbridges and underpasses, respectively. Women and older participants were willing to walk longer additional times to avoid those facilities. Participants only avoid crossing the road if the additional time to use straight signalised crossings is at least 20.9 minutes. The estimated values for the willingness to walk were slightly smaller when using a conditional logit model. The study provides information that is useful for policy decisions about the frequency and the type of pedestrian facilities provided to cross busy roads

The development of perceptual averaging: learning what to do, not just how to do it

The mature visual system condenses complex scenes into simple summary statistics (e.g., average size, location, orientation, etc.). However, children, often perform poorly on perceptual averaging tasks. Children's difficulties are typically thought to represent the suboptimal implementation of an adult-like strategy. This paper examines another possibility: that children actually make decisions in a qualitatively different way to adults (optimal implementation of a non-ideal strategy). Ninety children (6-7, 8-9, 10-11 years) and 30 adults were asked to locate the middle of randomly generated dot-clouds. Nine plausible decision strategies were formulated, and each was fitted to observers' trial-by-trial response data (Reverse Correlation). When the number of visual elements was low (N < 6), children used a qualitatively different decision strategy from adults: appearing to "join up the dots" and locate the gravitational center of the enclosing shape. Given denser displays, both children and adults used an ideal strategy of arithmetically averaging individual points. Accounting for this difference in decision strategy explained 29% of children's lower precision. These findings suggest that children are not simply suboptimal at performing adult-like computations, but may at times use sensible, but qualitatively different strategies to make perceptual judgments. Learning which strategy is best in which circumstance might be an important driving factor of perceptual development

How do pedestrians balance safety, walking time, and the utility of crossing the road? A stated preference study

This paper presents the results of a stated preference survey to estimate the value of reductions in community severance (the “barrier effect” of transport infrastructure on the mobility of pedestrians). In a first exercise, participants chose between crossing a road in a place without designated facilities or walking additional minutes to a place where the road is covered over. Half of the participants never chose to cross, regardless of the road design, traffic characteristics, and length of the detour. On average, the other half would only cross the road if the detour was at least 7.9 minutes (or longer, if the road had extra traffic lanes, no central reservation, or high traffic density). In a second exercise, participants were asked whether they would cross the road to access a cheaper shop or a bus stop on the other side of the road, instead of a more expensive one on their side of the road. 38% never chose to cross. The other 62% would only cross a road with high traffic density if the saving was at least £2.8, but would cross roads with other characteristics for smaller savings. Overall, the study suggests that many people are not willing to trade-off pedestrian safety with shorter walking times or cost savings. People who are willing to trade-off tend to attach greater importance to traffic density, comparing with aspects such as road design and traffic speed

Street Mobility Project: Video surveys

The Street Mobility toolkit provides a set of tools that can be used by practitioners, local communities, and others, to assess and value the costs of the 'barrier effect' of roads. This document describes how to use video surveys to who uses busy roads, when, and how. The comparison of the actual pedestrian flows along different roads with what might be expected from walkability models can give an indication of places that pedestrians avoid. These may indicate where action is needed to improve the conditions for pedestrians and to facilitate more walking for travel in the area. The data collected can also be used to identify particular problems faced by pedestrians at different times of the day, which may be related to variations in the levels or types of motor traffic

Pedestrians avoid busy roads: evidence from video surveys and bus stop data

This paper assesses the influence of motorised traffic on pedestrian mobility in an area in London surrounded by major roads. Pavement and crossing flows obtained by a video survey are analysed in comparison with data on bus stop usage. The flows along the busiest road are lower than it would be expected given the location of the road along the walking routes to bus stops. The propensity to cross the road (overall and informally) correlates negatively with traffic levels, especially in roads with medium traffic speeds. The hypothesis that local residents avoid crossing the road away from designated facilities is also supported by differences in the number of passengers boarding and alighting buses at different stops