Impact of small-scale vegetation structure on tephra layer preservation.

The factors that influence tephra layer taphonomy are poorly understood, but vegetation cover is likely to play a role in the preservation of terrestrial tephra deposits. The impact of vegetation on tephra layer preservation is important because: 1) the morphology of tephra layers could record key characteristics of past land surfaces and 2) vegetation-driven variability in tephra thickness could affect attempts to infer eruption and dispersion parameters. We investigated small- (metre-) scale interactions between vegetation and a thin (<10 cm), recent tephra layer. We conducted surveys of vegetation structure and tephra thickness at two locations which received a similar tephra deposit, but had contrasting vegetation cover (moss vs shrub). The tephra layer was thicker and less variable under shrub cover. Vegetation structure and layer thickness were correlated on the moss site but not under shrub cover, where the canopy reduced the influence of understory vegetation on layer morphology. Our results show that vegetation structure can influence tephra layer thickness on both small and medium (site) scales. These findings suggest that some tephra layers may carry a signal of past vegetation cover. They also have implications for the sampling effort required to reliably estimate the parameters of initial deposits

Examination of a contested landscape : archaeological prospection on the eastern shore of Nova Scotia

xi, 233 leaves : ill. (chiefly col.), maps (chiefly col.) ; 29 cm.Includes abstract and appendices.Includes bibliographical references (leaves 196-213).From 1749–1755, a migration of Acadians from Nova Scotia saw hundreds relocate to Île Saint-Jean and Île Royale. Among them, following the founding of Halifax, were the Acadians of Chezzetcook, Mirliguèche and those living at modern-day Lawrencetown. In 1753 and 1754, the French and Mi'kmaq community of Mirliguèche and an area east of Halifax called “Musquodoboit” were resettled by the British and renamed Lunenburg and Lawrencetown. These efforts at resettlement of deserted French communities would presage the reoccupation of Acadian land established after 1760. This thesis is a study of a landscape. It utilizes an interdisciplinary approach of historical research, cartographic analysis, community engagement, landscape archaeology, remote sensing and empirical archaeological investigation to explore a historiographically neglected episode in Nova Scotia history. This work approaches events surrounding the abandonment of the eastern shore and resettlement of Lawrencetown as a micro-history of successive land use

Integrating Video Content into Humanities Teaching: a case study

Screencasts and other video content offer an innovative means of improving communication between tutors and students and addressing student concerns about limited contact hours, which can be particularly pressing in English Literature. Our students’ comments make it clear they require further guidance and support, despite extensive feedback provided on written work and guidance provided in module handbooks. This likely results from the nature of the subject which foregrounds self-reflective learning and has fewer contact hours than science subjects. In the most recent NSS, 76% of Keele English students felt that ‘the criteria used in marking have been clear in advance’ and 81% felt they had ‘received sufficient advice and guidance’ (unistats.ac.uk). These percentages are much lower than other areas on the NSS (such as the 90% of Keele’s English students who said ‘staff have made the subject interesting’, or the 100% who felt ‘my course has provided me with opportunities to explore ideas or concepts in depth’). The impact of this communication gap between staff and students is felt more widely; only 57% of students responding to the most recent NSS said they ‘feel part of a community of staff and students’. This paper examines the use of video technology to supplement three areas of student learning: seminar preparation, assessment guidance, and assessment feedback. We prepared three informational videos to supplement a second-year English Literature module in order to explore the impact of this technology on student achievement, student feedback, and staff time and resources, to determine whether screencasts offer a feasible solution to the students’ perception of a communication gap between students and tutors in the English programme

Shigellosis: An Old Disease in New Clothes?

Sansonetti discusses a "landmark" study of the epidemiology of shigellosis, involving over 600,000 people of all ages in six Asian countries

The 1991-2012 Light Curve of the Old Nova HR LYRAE

The 22 yr light curve of HR Lyr, acquired with a typical cadence of 2-6 days, is examined for periodic and quasi-periodic variations. No persistent periodicities are revealed. Rather, the light curve variations often take the form of nearly linear rises and falls having typical e-folding times of about 100 days. Occasional ~0.6 mag outbursts are also seen, with properties similar to those of small outbursts found in some nova-like cataclysmic variables. When the photometry is formed into yearly averages, a decline of 0.012 ± 0.005 mag yr–1 is apparent, consistent with the fading of irradiation-induced $\dot{M}$ following the nova. The equivalent width of Hα is tabulated at three epochs over the interval 1986-2008 in order to compare with a recent result for DK Lac in which Hα was found to be fading 50 yr after the nova. However, our results for such a fading in HR Lyr are inconclusive. © 2014. The American Astronomical Society. All rights reserved

Occurrence of Lake Chub, Couesius plumbeus, in Northern Labrador

Lake Chub (Couesius plumbeus) were recently found in seven previously undocumented locations in northern Labrador. These populations represent the first recorded accounts of this species in the Labrador region north of the Churchill River drainage and east of the George River. Lake Chub likely invaded this region via dispersal routes provided by eastern spillways of glacial Lake Naskaupi

The Significance of the Bifunctional Kinase/Phosphatase Activities of Diphosphoinositol Pentakisphosphate Kinases (PPIP5Ks) for Coupling Inositol Pyrophosphate Cell Signaling to Cellular Phosphate Homeostasis

Proteins responsible for Pi homeostasis are critical for all life. In Saccharomyces cerevisiae, extracellular [Pi] is “sensed” by the inositol-hexakisphosphate kinase (IP6K) that synthesizes the intracellular inositol pyrophosphate 5-diphosphoinositol 1,2,3,4,6-pentakisphosphate (5-InsP7) as follows: during a period of Pi starvation, there is a decline in cellular [ATP]; the unusually low affinity of IP6Ks for ATP compels 5-InsP7 levels to fall in parallel (Azevedo, C., and Saiardi, A. (2017) Trends. Biochem. Sci. 42, 219–231. Hitherto, such Pi sensing has not been documented in metazoans. Here, using a human intestinal epithelial cell line (HCT116), we show that levels of both 5-InsP7 and ATP decrease upon [Pi] starvation and subsequently recover during Pi replenishment. However, a separate inositol pyrophosphate, 1,5-bisdiphosphoinositol 2,3,4,6-tetrakisphosphate (InsP8), reacts more dramatically (i.e. with a wider dynamic range and greater sensitivity). To understand this novel InsP8 response, we characterized kinetic properties of the bifunctional 5-InsP7 kinase/InsP8 phosphatase activities of full-length diphosphoinositol pentakisphosphate kinases (PPIP5Ks). These data fulfil previously published criteria for any bifunctional kinase/phosphatase to exhibit concentration robustness, permitting levels of the kinase product (InsP8 in this case) to fluctuate independently of varying precursor (i.e. 5-InsP7) pool size. Moreover, we report that InsP8 phosphatase activities of PPIP5Ks are strongly inhibited by Pi (40–90% within the 0–1 mm range). For PPIP5K2, Pi sensing by InsP8 is amplified by a 2-fold activation of 5-InsP7 kinase activity by Pi within the 0–5 mm range. Overall, our data reveal mechanisms that can contribute to specificity in inositol pyrophosphate signaling, regulating InsP8 turnover independently of 5-InsP7, in response to fluctuations in extracellular supply of a key nutrient