Demountable connection for polymer optical fiber grating sensors

The authors fabricated a demountable Ferrule connector/Physical contact connection between silica fiber and a polymer optical fiber (POF) containing a fiber Bragg grating. The use of a connector for POF grating sensors eliminates the limitations of ultraviolet glued connections and increases the ease with which the devices can be applied to real-world measurement tasks. © 2012 Society of Photo-Optical Instrumentation Engineers (SPIE)

The effect of woodland area on avian community composition in a fragmented southern UK landscape and associated management recommendations

Capsule. Smaller woodlands not only support fewer species, but also show different avian community composition, due to loss of woodland interior and an increase in edge habitat. Aims. To use observed community composition changes, rather than traditional total species richness-area relations, to make area-specific management recommendations for optimising woodland habitat for avian communities in fragmented landscapes. Methods. We selected a sample of 17 woodlands with area 0.2<A<120ha in Oxfordshire, UK. Three dawn area searches were conducted in each woodland between 1st April and 28th May 2016, recording encounter rates for each species. The impact of internal habitat variation on woodland comparability was assessed using habitat surveys. Results. Woodlands with A3.6ha were all consistent with a mean total richness of 25.4±0.6 species, however the number of woodland specialists continued to increase with woodland area. Woodland generalists dominated the total encounter rate across the area range, however the fractional contribution of woodland specialists showed a significant positive correlation with woodland area, while the fractional contribution of non-woodland species significantly decreased. Non-woodland species numbers peaked in mid-sized woodlands with enhanced habitat heterogeneity. Conclusions. Community composition analysis enables more targeted recommendations than total species richness analysis, specifically: large woodlands (>25ha) in southern UK should focus conservation efforts on providing the specific internal habitats required by woodland specialists; medium-sized woodlands (approximately 4<A<25ha) should focus on promoting internal habitat variety, which can benefit both woodland species and non-woodland species of conservation concern in the surrounding landscape; small woodlands (<4ha) should focus on providing nesting opportunities for non-woodland species and on improving connectivity to maximise habitat for woodland generalists and facilitate movement of woodland specialists

Wavelength drift of PMMA-based optical fiber bragg grating induced by optical absorption

The transmission loss in polymer optical fiber (POF) is much higher than that in silica fiber. Very strong absorption bands dominate throughout the visible and near infrared. Optical absorption increases the internal temperature of the polymer fiber and reduces the wavelength of any POF Bragg grating (POFBG) inscribed within the fiber. In this letter, we have investigated the wavelength drift of FBGs inscribed in poly(methyl methacrylate)-based fiber under illumination at different wavelengths. The experiments have shown that the characteristic wavelength of such a POFBG starts decreasing after a light source is applied to it. This decrease continues until equilibrium inside the fiber is established, depending on the surrounding humidity, optical power applied, and operation wavelength

Wooded streets, but not streetlight dimming, favour bat activity in a temperate urban setting

Urbanization damages biodiversity, reducing people’s connection to nature and negatively impacting the survivability of local species. However, with small adjustments, the damage could be mitigated. In temperate regions, several bat species inhabit urban areas, and with urbanization set to increase, adapting urban areas to improve their suitability for bats is imperative. Therefore, we investigated if wooded streets and streetlight dimming in an urban setting influenced bat activity. Static bat detectors were used to compare wooded versus non-wooded, and bright versus dim streets in Leicester, UK, on predominantly residential streets. The collected calls were quantified into bat activity (passes per night). Six species were identified, but the common pipistrelle (Pipistrellus pipistrellus) was dominant, making up 94.1% of all calls, so it was the sole species included in the statistical model. Wooded streets had significantly higher bat activity than non-wooded streets, but bright and dim streets were not significantly different. The results suggest that wooded streets were being used as green corridors, with common pipistrelles possibly following them to conceal themselves from predators, such as the tawny owl, and the proliferation of wooded streets in urban areas could allow the formation of better-connected populations. Streetlight dimming did not affect bat activity, but no light-averse bats were detected, likely because even the most dimmed streets deterred them despite street lighting increasing food availability by attracting insects. Therefore, an alternate solution, such as part-night lighting, may be required to increase the suitability of urban areas to light-averse species

Wherever I may roam: social viscosity and kin affiliation in a wild population despite natal dispersal

Dispersal affects the social contexts individuals experience by redistributing individuals in space, and the nature of social interactions can have important fitness consequences. During the vagrancy stage of natal dispersal, after an individual has left its natal site and before it has settled to breed, social affiliations might be predicted by opportunities to associate (e.g., distance in space and time between natal points of origin) or kin preferences. We investigated the social structure of a population of juvenile great tits (Parus major) and asked whether social affiliations during vagrancy were predicted by 1) the distance between natal nest-boxes, 2) synchrony in fledge dates, and 3) accounting for spatial and temporal predictors, whether siblings tended to stay together. We show that association strength was affected predominantly by spatial proximity at fledging and, to a lesser extent, temporal proximity in birth dates. Independently of spatial and temporal effects, sibling pairs associated more often than expected by chance. Our results suggest that the structure of the winter population is shaped primarily by limits to dispersal through incomplete population mixing. In addition, our results reveal kin structure, and hence the scope for fitness-related interactions between particular classes of kin. Both spatial-mediated and socially mediated population structuring can have implications for our understanding of the evolution of sociality

Interactive single cell RNA-Seq analysis with Single Cell Toolkit (SCTK)

I will present the Single Cell Toolkit (SCTK), an R package and interactive single cell RNA-sequencing (scRNA-Seq) analysis package that provides the first complete workflow for scRNA-Seq data analysis and visualization using a set of R functions and an interactive web interface. Users can perform analysis with modules for filtering raw results, clustering, batch correction, differential expression, pathway enrichment, and scRNA-Seq study design. The toolkit supports command line or pipeline data processing, and results can be loaded into the GUI for additional exploration and downstream analysis. We demonstrate the effectiveness of the SCTK on multiple scRNA-seq examples, including data from mucosal-associated invariant T cells, induced pluripotent stem cells, and breast cancer tumor cells. While other scRNA-Seq analysis tools exist, the SCTK is the first fully interactive analysis toolkit for scRNA-Seq data available within the R language.NIH U01CA22041