Middle to late Pleistocene palaeoecological reconstructions and palaeotemperature estimates for cold/cool stage deposits at Whittlesey, eastern England

Fossiliferous beds in a complex sequence of late Middle to Late Pleistocene deposits at Whittlesey, eastern England, provided a rare opportunity for a multidisciplinary study of the palaeoecology of cool/cold stage deposits from different glacial stages. The fossiliferous sediments investigated form part of the River Nene 1st Terrace. Three of the four fossil assemblages investigated pre-date the last interglacial stage (Ipswichian/Eemian/marine oxygen isotope stage (MIS) 5e), whereas the other dates to part of the MIS 3 interstadial complex (Middle Devensian/Weichselian). Pollen, plant macrofossil, molluscan, coleopteran, ostracod, foraminifera and vertebrate data are available to a greater or lesser extent for each cool/cold stage assemblage, and they broadly present the same ecological picture for each one: a continuum from low-energy permanent to non-permanent aquatic habitats through marshland with associated waterside taxa, together with flood influxes of fluvial, riparian and ruderal taxa. Although each fossil assemblage records cool/cold climatic conditions, to a greater or lesser extent, these conditions are more apparent in the insect and ostracod faunas. In comparison with results published for the Last Glacial Maximum (LGM) stadial in The Netherlands, palaeotemperature estimates based on ranges of mutual agreement between independent coleopteran and ostracod methods for the three pre-Ipswichian/Eemian assemblages indicate minimum mean July air temperatures that are from +1° to +3 °C warmer, but January values that embrace the −8 °C estimate for the LGM. There is, however, a disparity between the coleopteran and ostracod palaeotemperature estimates for the Middle Devensian/Weichselian fossil assemblage, which are based on two different sample stratigraphic levels; the lower, coleopteran assemblage is indicative of very cool, continental climates, whereas the stratigraphically slightly higher ostracod assemblage suggests a climatic amelioration. Lack of numerical age-estimates prevents a robust stratigraphical interpretation, but the youngest pre-Ipswichian/Eemian fossil assemblage could date to the MIS 7–6 transition, at a time when cooling possibly preceded glacially driven sea-level fall. It is apparent from the rich coleopteran data that some continental cold-indicator taxa also appeared in pre-Ipswichian/Eemian cold stages and therefore assignment of continental cold-indicator taxa to particular Devensian/Weichselian intervals should be undertaken with care

Quantifying surgical access in eyebrow craniotomy with and without orbital bar removal - cadaver and surgical phantom studies

Background: Eyebrow craniotomy is a recently described minimally invasive approach for tackling primarily pathology of the anterior skull base. The removal of the orbital bar may further expand the surgical corridor of this exposure, but the extent of benefit is poorly quantified. We assessed the effect of orbital bar removal with regards to surgical access in the eyebrow craniotomy using classic morphometric measurements in cadaver heads. Using surgical phantoms and neuronavigation, we also measured the \u27working volume\u27, a new parameter for characterising the volume of surgical access in these approaches. Methods: Silicon injected cadaver heads (n=5) were used for morphometric analysis of the eyebrow craniotomy with and without orbital bar removal. Working depths and \u27working areas\u27 of surgical access were measured as defined by key anatomical landmarks. The eyebrow craniotomy with or without orbital bar removal was also simulated using surgical phantoms (n=3, 90-120 points per trial), calibrated against a frameless neuronavigation system. Working volume was derived from reference coordinates recorded along the anatomical borders of the eyebrow craniotomy using the α-shape algorithm in R statistics. Results: In cadaver heads, eyebrow craniotomy with removal of the orbital bar reduced the working depth to the ipsilateral anterior clinoid process (42±2 versus 33±3 mm; p\u3c0.05), but the working areas as defined by deep neurovascular and bony landmarks was statistically unchanged (total working areas of 418±80 cm2 versus 334±48 cm2; p=0.4). In surgical phantom studies, however, working-volume for the simulated eyebrow craniotomies was increased with orbital bar removal (16±1 cm3 versus 21±1 cm 3; p\u3c0.01). Conclusions: In laboratory studies, orbital bar removal in eyebrow craniotomy provides a modest reduction in working depth and increase in the working volume. But this must be weighed up against the added morbidity of the procedure. Working volume, a newly developed parameter may provide a more meaningful endpoint for characterising the surgical access for different surgical approaches and it could be applied to other operative cases undertaken with frameless neuronavigation. © 2013 Springer-Verlag

On balanced sets and related structures (Algebraic Combinatorics)

Table S7. Thermophile species in channel C and at other Ipswichian sites according to pollen biozonation