Topic Similarity Networks: Visual Analytics for Large Document Sets

We investigate ways in which to improve the interpretability of LDA topic models by better analyzing and visualizing their outputs. We focus on examining what we refer to as topic similarity networks: graphs in which nodes represent latent topics in text collections and links represent similarity among topics. We describe efficient and effective approaches to both building and labeling such networks. Visualizations of topic models based on these networks are shown to be a powerful means of exploring, characterizing, and summarizing large collections of unstructured text documents. They help to "tease out" non-obvious connections among different sets of documents and provide insights into how topics form larger themes. We demonstrate the efficacy and practicality of these approaches through two case studies: 1) NSF grants for basic research spanning a 14 year period and 2) the entire English portion of Wikipedia.Comment: 9 pages; 2014 IEEE International Conference on Big Data (IEEE BigData 2014

Laser-Doppler gas-velocity instrument

Three-D instrument using a laser light source measures both turbulence and mean velocity of subsonic and supersonic gas flows. This instrument is based on the measurement of the Doppler frequency shift of light waves scattered by moving particles in the gas stream

Laser Doppler velocity instrument

Laser Doppler velocity instrument for measuring turbulence and mean velocity in subsonic and supersonic gas flow

Mars simulated exposure and the characteristic Raman biosignatures of amino acids and halophilic microbes

Though Raman bands of α-amino acids (AA) are well documented, often only the strongest intensity bands are quoted as identifiers (e.g. Jenkins et al., 2005; De Gelder et al., 2007; Zhu et al., 2011). Unknown regolith mixtures on Mars-sampling missions could obscure these bands. Here the case is made for determining, via a statistical method, sets of characteristic bands to be used as identifiers, independent of band intensity or number of bands (Rolfe et al., 2016). AA have upwards of 25 potentially identifying bands and this method defines sets of 10–19 bands per AA. Examination of AA-doped Mars-like basalt resulted in a maximum of eight bands being identified, as some characteristic bands were obscured by mineral bands, including the strongest intensity band in some cases. This proved the need for characteristic bands to be defined, enabling successful identification of AA. The ESA ExoMars Rover mission will crush and then pass the sample to the Raman Laser Spectrometer. We crushed a Mars-like basalt to a similar grain size expected to be created by the rover. Our samples were doped with 1 % (by weight) AA samples, resulting in no detection of AA, because of loss of original spatial context and spaces between the grains. We recommend that Raman spectroscopy on future missions should be conducted before the sample is crushed. Halite-entombed halophilic microbes, known to survive being entombed, were exposed to Mars-like surface (including temperature, pressure, atmospheric composition and UV) and freeze-thaw cycle (plus pressure and atmospheric composition) conditions. This test on the survival of the microbes showed that survival rates quickly deteriorated in surface conditions, but freeze-thaw cycle samples had well preserved Raman biosignatures, indicating that similar signatures could be detectable on Mars if similar life persists in evaporitic material or brines today

PIRATE: A Remotely-Operable Telescope Facility for Research and Education

We introduce PIRATE, a new remotely-operable telescope facility for use in research and education, constructed from 'off-the-shelf' hardware, operated by The Open University. We focus on the PIRATE Mark 1 operational phase where PIRATE was equipped with a widely- used 0.35m Schmidt-Cassegrain system (now replaced with a 0.425m corrected Dall Kirkham astrograph). Situated at the Observatori Astronomic de Mallorca, PIRATE is currently used to follow up potential transiting extrasolar planet candidates produced by the SuperWASP North experiment, as well as to hunt for novae in M31 and other nearby galaxies. It is operated by a mixture of commercially available software and proprietary software developed at the Open University. We discuss problems associated with performing precision time series photometry when using a German Equatorial Mount, investigating the overall performance of such 'off-the-shelf' solutions in both research and teaching applications. We conclude that PIRATE is a cost-effective research facility, and also provides exciting prospects for undergraduate astronomy. PIRATE has broken new ground in offering practical astronomy education to distance-learning students in their own homes.Comment: Accepted for publication in PASP. 14 pages, 11 figure

Raman spectroscopy of amino acids and other biomarkers on Mars

In the search for life elsewhere in the Solar System, our nearest planetary neighbour, Mars, offers great potential for finding past or present life. Whether life is extant or not, signs of biological activity can be inferred through the detection of specific biomarkers, such as amino acids. Raman spectroscopy is an extremely effective method of detecting biomarkers. It is non-destructive and is used to identify different molecular species through observations of the Raman shift created by the bonds within the molecule. Amino acids that are part of a biological system could provide potential evidence of life on Mars. It is thought that amino acids could survive in the sub-surface of Mars, making them a high-priority biomarker candidate. Terrestrial life utilises homochiral amino acids, and if detected on Mars it would provide an important piece of evidence for the case for life on Mars. In this work, a number of biologically essential amino acids that are utilised in terrestrial organisms will be studied using Raman spectroscopy. We aim to characterise the Raman signature for these molecules in detail in order to aid interpretation of results from future Mars landers, and presented here are initial results from the preliminary investigations. Further work will extend to other high-priority biomarkers that may be found at the surface/sub-surface of Mars

Detecting biomarkers on Mars using Raman spectroscopy

Raman spectroscopy is a powerful technique for the characterisation of organic molecules as it provides a unique ‘fingerprint’ spectrum. Incident monochromatic light on a sample is shifted in wavelength giving rise to the Raman spectrum, with peaks that are attributable to the specific vibrational bonds within the molecule. Raman spectroscopy is useful for analysing not only geological samples but also biological molecules, and has been recommended for use as a detection method (among others) for biomarkers on missions to planetary bodies [1]. The ExoMars Rover mission is due to launch in 2018 with a Raman spectrometer as part of its scientific payload [2]. Amino acids, the ‘building-blocks’ of proteins, have been identified as a high priority biomarker in the search for evidence of life on planetary bodies [3]. Raman spectroscopy is often a qualitative method, but if signatures of biomarkers are detected by Raman spectroscopy, it is critical that correct identification of such biomarkers can be undertaken. To aid in molecule identification, we take a statistical approach to determine the position of characteristic peaks of several amino acids. We present evidence for statistically significant changes in the peak positions when using different excitation wavelengths. Furthermore, we present evidence that martian conditions have an effect on the Raman spectra of amino acids, which could have implications when performing in situ measurements on Mars. 1. Jehlicka, J., H.G.M. Edwards, and P. Vítek, Assessment of Raman spectroscopy as a tool for the non-destructive identification of organic minerals and biomolecules for Mars studies. Planetary and Space Science, 2009. 57(5-6): p. 606-613. 2. Edwards, H.G.M., I. Hutchinson, and R. Ingley, The ExoMars Raman spectrometer and the identification of biogeological spectroscopic signatures using a flight-like prototype. Analytical and Bioanalytical Chemistry, 2012. 404(6-7): p. 1723-1731. 3. Parnell, J., et al., Searching for Life on Mars: Selection of Molecular Targets for ESA's Aurora ExoMars Mission. Astrobiology, 2007. 7(4): p. 578-604

Adapting to the digital age: a narrative approach

The article adopts a narrative inquiry approach to foreground informal learning and exposes a collection of stories from tutors about how they adapted comfortably to the digital age. We were concerned that despite substantial evidence that bringing about changes in pedagogic practices can be difficult, there is a gap in convincing approaches to help in this respect. In this context, this project takes a “bottom-up” approach and synthesises several life-stories into a single persuasive narrative to support the process of adapting to digital change. The project foregrounds the small, every-day motivating moments, cultural features and environmental factors in people's diverse lives which may have contributed to their positive dispositions towards change in relation to technology enhanced learning. We expect that such narrative approaches could serve to support colleagues in other institutions to warm up to ever-changing technological advances