FLASH redshift survey - I. Observations and Catalogue

The FLAIR Shapley-Hydra (FLASH) redshift survey catalogue consists of 4613 galaxies brighter than \bJ = 16.7 (corrected for Galactic extinction) over a 605 sq. degree region of sky in the general direction of the Local Group motion. The survey region is an approximately 60\degr \times 10\degr strip spanning the sky from the Shapley Supercluster to the Hydra cluster, and contains 3141 galaxies with measured redshifts. Designed to explore the effect of the galaxy concentrations in this direction (in particular the Supergalactic plane and the Shapley Supercluster) upon the Local Group motion, the 68% completeness allows us to sample the large-scale structure better than similar sparsely-sampled surveys. The survey region does not overlap with the areas covered by ongoing wide-angle (Sloan or 2dF) complete redshift surveys. In this paper, the first in a series, we describe the observation and data reduction procedures, the analysis for the redshift errors and survey completeness, and present the survey data.Comment: 12 pages, 12 figures, mn.sty, submitted to MNRA

The Potential effect of Low Cell Osmolarity on Cell Function through decreased concentration of enzyme substrates

© The Author(s) 2018. Published by Oxford University Press on behalf of the Society for Experimental Biology. All rights reserved. Some freshwater algae have lower (180 osmol m −3 ). Low osmolarities are related to the presence of flagella and the low energy cost of active water efflux following downhill water influx unconstrained by cell walls covering the plasmalemma, and the low resource cost of cell wall synthesis with the same mechanical degree of safety. One consequence of low intracellular osmolarity is limitation on the concentration of metabolites, that is, substrates and products of enzyme activity. Models of the flux through metabolic pathways, and hence the specific growth rate, using steady-state concentrations of enzymes and metabolites have involved organisms with intracellular metabolite osmolarities >280 osmol m −3 , where the metabolite concentrations are much greater than the total osmolarity of some freshwater algae. Since the protein concentration (mol m −3 ) in the cells and the specific growth rates of freshwater cells with low and with higher intracellular osmolarity are highly similar, the models of trade-offs between enzyme and metabolite concentrations for cells with high intracellular osmolarity need modification for cells with low intracellular osmolarity. The soluble free-radical scavenger ascorbate can constitute as little as 0.2% of the low intracellular metabolite concentration (mol m −3 ) of low-intracellular-osmolarity cells

Medieval landscapes and lordship in South Uist

This thesis examines the structures of society and lordship in the Middle Ages in South Uist through historical documentation, oral-tradition, cultural landscapes, monuments and settlement patterns. In this thesis, the medieval period has been defined as that between c. 1000 and c. 1650. The historical evidence is considered along with archaeological evidence to create a holistic understanding of medieval social developments in South Uist. The results have ramifications for interpreting contemporaneous society throughout Scotland and Ireland. The study focuses on rural settlement (farms, townships, field- and transhumance-systems) and high-status monuments (churches, duns and castles). Developments visible in both the historical and archaeological record demonstrate that considerable social, economic and cultural changes took place within the landscape of South Uist throughout the Middle Ages. However, the nature of the evidence polarises the study into two time spheres: the Norse period, c. 1000 - c. 1400, and the Late Medieval period, c. 1550 - c. 1650. Remains belonging to the intervening period have proved difficult to locate. The Norse period landscape was characterised by dispersed farmsteads, possibly siting within an enclosed field-system. It is probable that these farmsteads originated as the homesteads of Viking Age settlers. Between the eleventh century and the end of the 1300s, there was a trend towards social and economic centralisation and the creation of an increasingly formalised social hierarchy: manifestations of this can be seen in the archaeological record and a new system of taxation. Archaeologically this is revealed by increasing divergence in the sizes of farmsteads, the largest of which also exhibit signs of industrial and agricultural control. Increased social differentiation is additionally reflected in artefact assemblages

What is the limit for photoautotrophic plankton growth rates?

© 2016 The Author. Knowing the potential maximum photoautotrophic growth rate for planktonic primary producers is fundamental to our understanding of trophic and biogeochemical processes, and of importance in applied phycology. When dayintegrated C-specific growth is considered over natural light:dark cycles, plausible RuBisCO activity (Kcat coupled with cellular RuBisCO content) caps growth to less than a few doubling per day. Prolonged periods of C-specific growth rates above ca. 1.3 d thus appear increasingly implausible. Discrepancies between RuBisCO-capped rates and reported microalgal-specific growth rates, including temperature-growth rate relationships, may be explained by transformational errors in growth rate determinations made by reference to cell counts or most often chlorophyll, or by extrapolations from short-Term measurements. Coupled studies of enzyme activity and day-on-day C-specific growth rates are required to provide definitive evidence of high growth rates. It seems likely, however, that selective pressure to evolve a RuBisCO with a high Kcat (with a likely concomitant increase in Km for CO2) would be low, as other factors such as light limitation (developing during biomass growth due to self-shading), nutrient limitations, CO2 depletion and pH elevation, would all rapidly depress realized specific growth rates