Fish powder as a low-cost component in media for producing bacterial cellulose

Some bacteria can produce extracellular bacterial cellulose (BC). This polysaccharide is chemically identical to cellulose produced by plants but has no associated lignin and hemicelluloses. The unique mechanical properties, chemical stability and purity allow BC to be exploited for a range of biomedical applications. However, medium costs limit commercial BC production. The suitability of using fish powder as a low-cost media component for producing BC by submerged culture of Gluconacetobacter xylinus in shake flasks was investigated. Fish powder was made by drying and grinding Koi carp (Cyprinus carpio), a pest fish in New Zealand waterways. Fermentations were done at 30oC in a growth medium containing 50 g/L glucose, the required minerals, and either 5 g/L yeast extract or 15 g/L fish powder, The BC yield on both yeast extract and fish powder was 0.04 g/g glucose, demonstrating fish powder was a suitable low cost ingredient for supplying nitrogen and amino acids in the media

Microwave Spectroscopy

Contains reports on two research projects

Adoption of sustainable retrofit in UK social housing 2010 – 2015

Purpose The Retrofit State of the Nation Survey has tracked the perceptions of social housing sector professionals’ views of retrofit since 2010. It has taken the form of 3 surveys conducted in 2010, 2013 and 2015. Here we bring together the three surveys to specifically address the adoption and perceived effectiveness of retrofit technology in social housing projects. This identifies the changing perceptions of social housing professionals over a period of significant policy change within in the sector. Design/methodology/approach The research takes the form of a cross-sectional attitudinal, self-completion survey, covering sections considering the adoption levels and perceived effectiveness of different retrofit technologies. The target sample was medium to larger scale registered social housing providers. The surveys were conducted in 2010, 2013, and 2015. Findings In terms of effectiveness, the reliance on tried and tested technologies is apparent. Emerging or more complex technologies have declined in perceived effectiveness over the period. It is clear that social housing has adopted a wide range of technologies, and the larger providers, with whom this survey is undertaken, potentially represent a significant pool of UK retrofit experience. Originality/value The survey provides a record of the changing attitudes of social housing providers to specific technologies over the period 2010-2015, which has seen significant changes in energy and social housing policy. The findings show the link between policy instruments and adoption, with policy instruments mapping to adoption in the sector. Perceived effectiveness reflects a preference for more established technologies, an issue that is highlighted in the recent Bonfield Review

Evaluating Matrix Circuits

The circuit evaluation problem (also known as the compressed word problem) for finitely generated linear groups is studied. The best upper bound for this problem is $\mathsf{coRP}$, which is shown by a reduction to polynomial identity testing. Conversely, the compressed word problem for the linear group $\mathsf{SL}_3(\mathbb{Z})$ is equivalent to polynomial identity testing. In the paper, it is shown that the compressed word problem for every finitely generated nilpotent group is in $\mathsf{DET} \subseteq \mathsf{NC}^2$. Within the larger class of polycyclic groups we find examples where the compressed word problem is at least as hard as polynomial identity testing for skew arithmetic circuits

Direct reaction measurements with a 132Sn radioactive ion beam

The (d,p) neutron transfer and (d,d) elastic scattering reactions were measured in inverse kinematics using a radioactive ion beam of 132Sn at 630 MeV. The elastic scattering data were taken in a region where Rutherford scattering dominated the reaction, and nuclear effects account for less than 8% of the cross section. The magnitude of the nuclear effects was found to be independent of the optical potential used, allowing the transfer data to be normalized in a reliable manner. The neutron-transfer reaction populated a previously unmeasured state at 1363 keV, which is most likely the single-particle 3p1/2 state expected above the N=82 shell closure. The data were analyzed using finite range adiabatic wave calculations and the results compared with the previous analysis using the distorted wave Born approximation. Angular distributions for the ground and first excited states are consistent with the previous tentative spin and parity assignments. Spectroscopic factors extracted from the differential cross sections are similar to those found for the one neutron states beyond the benchmark doubly-magic nucleus 208Pb.Comment: 22 pages, 7 figure