Characterising and Testing Deep UV LEDs for Use in Space Applications

Deep ultraviolet (DUV) light sources are used to neutralise isolated test masses in highly sensitive space-based gravitational experiments. An example is the LISA Pathfinder charge management system, which uses low-pressure mercury lamps. A future gravitational-wave observatory such as eLISA will use UV light-emitting diodes (UV LEDs), which offer numerous advantages over traditional discharge lamps. Such devices have limited space heritage but are are now available from a number of commercial suppliers. Here we report on a test campaign that was carried out to quantify the general properties of three types of commercially available UV LEDs and demonstrate their suitability for use in space. Testing included general electrical and UV output measurements, spectral stability, pulsed performance, temperature dependence as well as thermal vacuum, radiation and vibration survivability

Editorial perspective: Leaving the baby in the bathwater in neurodevelopmental research

Neurodevelopmental conditions are characterised by differences in the way children interact with the people and environments around them. Despite extensive investigation, attempts to uncover the brain mechanisms that underpin neurodevelopmental conditions have yet to yield any translatable insights. We contend that one key reason is that psychologists and cognitive neuroscientists study brain function by taking children away from their environment, into a controlled lab setting. Here, we discuss recent research that has aimed to take a different approach, moving away from experimental control through isolation and stimulus manipulation, and towards approaches that embrace the measurement and targeted interrogation of naturalistic, user-defined and complex, multivariate datasets. We review three worked examples (of stress processing, early activity level in ADHD and social brain development in autism) to illustrate how these new approaches might lead to new conceptual and translatable insights into neurodevelopment

Oscillatory entrainment to our early social or physical environment and the emergence of volitional control

An individual’s early interactions with their environment are thought to be largely passive; through the early years, the capacity for volitional control develops. Here, we consider: how is the emergence of volitional control characterised by changes in the entrainment observed between internal activity (behaviour, physiology and brain activity) and the sights and sounds in our everyday environment (physical and social)? We differentiate between contingent responsiveness (entrainment driven by evoked responses to external events) and oscillatory entrainment (driven by internal oscillators becoming temporally aligned with external oscillators). We conclude that ample evidence suggests that children show behavioural, physiological and neural entrainment to their physical and social environment, irrespective of volitional attention control; however, evidence for oscillatory entrainment beyond contingent responsiveness is currently lacking. Evidence for how oscillatory entrainment changes over developmental time is also lacking. Finally, we suggest a mechanism through which periodic environmental rhythms might facilitate both sensory processing and the development of volitional control even in the absence of oscillatory entrainment

Cancer cell lines show high heritability for motility but not generation time

Tumour evolution depends on heritable differences between cells in traits affecting cell survival or replication. It is well established that cancer cells are genetically and phenotypically heterogeneous; however, the extent to which this phenotypic variation is heritable is far less well explored. Here, we estimate the broad-sense heritability (H2) of two cell traits related to cancer hallmarks––cell motility and generation time––within populations of four cancer cell lines in vitro and find that motility is strongly heritable. This heritability is stable across multiple cell generations, with heritability values at the high end of those measured for a range of traits in natural populations of animals or plants. These findings confirm a central assumption of cancer evolution, provide a first quantification of the evolvability of key traits in cancer cells and indicate that there is ample raw material for experimental evolution in cancer cell lines. Generation time, a trait directly affecting cell fitness, shows substantially lower values of heritability than cell speed, consistent with its having been under directional selection removing heritable variation

Northward range extension of Cyclinella tenuis Recluz

The venerid bivalve, C. tenuis, was described by Recluz (1852. Jour. de Conch., 3: 250) from Baie de la Pointe-a-Pitre, Guadeloupe in the Lesser Antilles. The northernmost occurrence of C. tenuis was reported as Cape Hatteras, North Carolina, by Dall (1889. U.S. Nat. Mus. Bull. 37, p. 56) and Johnson (1934. Proc. Boston Soc. Nat. Hist., 40: 48). (...

Outdoor learning in urban schools: Effects on 4–5 year old children's noise and physiological stress

Natural outdoor environments reduce physiological stress. But in an urban school context, does outdoor learning still have beneficial effects even where nature exposure is more limited? The current, pre-registered study used wearable devices including heart rate monitors and actigraphs to examine physiological stress in 4–5 year old children across 8 matched indoor and outdoor sessions (N = 76 children, N = 601 sessions in total). Results revealed that children's resting heart rates while seated and listening to a teacher were significantly lower when outside compared to indoors (p < 0.001, d = 0.512). Children also moved more while seated during indoor sessions (p < 0.001, d = 0.546). Despite activities and resources being matched across conditions, outdoor learning sessions were significantly quieter than indoor ones, both when children were seated, listening to a teacher (p = 0.004, d = −0.455) and when actively engaged in play and learning activities (p < 0.001, d = 1.064). There was a significant positive correlation between noise levels and resting heart rate in the indoor condition (r(97) = 0.364, p < 0.001) but not in the outdoor condition. These findings suggest that learning outdoors, even in urban settings, associates with lower physiological stress in children and that this effect may partly be due to reduced noise. The fact that noise associates with resting heart rate indoors but not outdoors may indicate that being outside buffers children against the stressful effects of excess noise

The LISA PathFinder DMU and Radiation Monitor

The LISA PathFinder DMU (Data Management Unit) flight model was formally accepted by ESA and ASD on 11 February 2010, after all hardware and software tests had been successfully completed. The diagnostics items are scheduled to be delivered by the end of 2010. In this paper we review the requirements and performance of this instrumentation, specially focusing on the Radiation Monitor and the DMU, as well as the status of their programmed use during mission operations, on which work is ongoing at the time of writing.Comment: 11 pages, 7 figures, prepared for the Proceedings of the 8th International LISA Symposium, Classical and Quantum Gravit

Parsing eye-tracking data of variable quality to provide accurate fixation duration estimates in infants and adults

Researchers studying infants’ spontaneous allocation of attention have traditionally relied on hand-coding infants’ direction of gaze from videos; these techniques have low temporal and spatial resolution and are labor intensive. Eye-tracking technology potentially allows for much more precise measurement of how attention is allocated at the subsecond scale, but a number of technical and methodological issues have given rise to caution about the quality and reliability of high temporal resolution data obtained from infants. We present analyses suggesting that when standard dispersal-based fixation detection algorithms are used to parse eye-tracking data obtained from infants, the results appear to be heavily influenced by interindividual variations in data quality. We discuss the causes of these artifacts, including fragmentary fixations arising from flickery or unreliable contact with the eyetracker and variable degrees of imprecision in reported position of gaze. We also present new algorithms designed to cope with these problems by including a number of new post hoc verification checks to identify and eliminate fixations that may be artifactual. We assess the results of our algorithms by testing their reliability using a variety of methods and on several data sets. We contend that, with appropriate data analysis methods, fixation duration can be a reliable and stable measure in infants. We conclude by discussing ways in which studying fixation durations during unconstrained orienting may offer insights into the relationship between attention and learning in naturalistic settings

Towards the upgrading of fermentation broths to advanced biofuels: a water tolerant catalyst for the conversion of ethanol to isobutanol

The conversion of methanol/ethanol mixtures to isobutanol with the pre-catalyst trans-[RuCl2(dppm)2] (1) is tolerant to the addition of water to the system, achieving an isobutanol yield of 36% at 78% selectivity with water concentrations typical of that of a crude fermentation broth.</p