Dating WF16: exploring the chronology of a Pre-Pottery Neolithic A settlement in the Southern Levant

A pre-requisite for understanding the transition to the Neolithic in the Levant is the establishment of a robust chronology, most notably for the late Epi-Palaeolithic and Pre-Pottery Neolithic A (PPNA) periods. In this contribution we undertake a dating analysis of the Pre-Pottery Neolithic site of WF16, southern Jordan, drawing on a sample of 46 AMS 14C dates. We utilise Bayesian methods to quantify an old wood effect to provide an offset that we factor into chronological models for a number of individual structures at WF16 and for the settlement as a whole. In doing so we address the influence of slope variations in the calibration curve and expose the significance of sediment and sample redeposition within sites of this nature. We conclude that for the excavated deposits at WF16 human activity is likely to have started by c. 11.84 ka cal bp and lasted for at least c. 1590 years, ceasing by c. 10.24 ka cal bp. This is marked by a particularly intensive period of activity lasting for c. 350 years centred on 11.25 ka cal bp followed by less intensive activity lasting a further c. 880 years. The study reveals the potential of WF16 as a laboratory to explore methodological issues concerning 14C dating of early Neolithic sites in arid, erosional environments.

Effect of air-drying pre-treatment on the characterization of forest soil carbon pools

Archived soils could represent a valuable resource for the spatio-temporal inventory of soil carbon stability. However, archived soils are usually air-dried before storage and the impact of a drying pretreatment on physically and chemically-defined C fractions has not yet been fully assessed. Through the comparison of field-moist and corresponding air-dried (at 25oC for 2 weeks) forest soil samples, we examined the effect of air-drying on: a) the quantity and the quality of cold- (CWEC) and hot-water (HWEC) extractable C and b) the concentration of C in physically isolated fractions (free- and intra-aggregate light and organo-mineral). Soil samples were collected from the organic (O) and mineral (A and B) horizons of three different forest soils from southeastern England: (i) Cambisol under Pine (Pinus nigra); (ii) Cambisol under Beech (Fagus sylvatica) and (iii) Gleysol under oak (Quercus robur). CWEC concentrations for dry samples were up to 2 times greater than for corresponding field moist samples and had significantly (p < 0.001) higher phenolic content. However, the effect of drying pretreatment on HWEC, its phenolic content was not significant (p > 0.05) for most samples. Dried soils had significantly (p < 0.001) higher concentrations of free light-C while having lower concentrations of intra-aggregate-C when compared to moist samples (p < 0.001). However, fine silt and clay fractions were not significantly affected by the drying pretreatment (p=0.789). Therefore, based on the results obtained from gleysol and cambisol forest soils studied here, C contents in hot-water extractions and fine particle size physical fractions (< 25µm) seem to be robust measurements for evaluating C fractions in dried stored forest soils. Further soil types should be tested to evaluate the wider generality of these findings.

“Action Research into Pre-sessional Students' Differentiation of Assessments: Using Findings to Improve Courses”

Conference proceedings papaer in Whong, M. (Ed.), Proceedings of the 2007 BALEAP conference: English in a globalising world: English as an academic lingua franca,. Bern: Peter Lang.

Syncytiotrophoblast extracellular vesicles from pre-eclampsia placentas differentially affect platelet function

Pre-eclampsia (PE) complicates around 3% of all pregnancies and is one of the most common causes of maternal mortality worldwide. The pathophysiology of PE remains unclear however its underlying cause originates from the placenta and manifests as raised blood pressure, proteinuria, vascular or systemic inflammation and hypercoagulation in the mother. Women who develop PE are also at significantly higher risk of subsequently developing cardiovascular (CV) disease. In PE, the failing endoplasmic reticulum, oxidative and inflammatory stressed syncytiotrophoblast layer of the placenta sheds increased numbers of syncytiotrophoblast extracellular vesicles (STBEV) into the maternal circulation. Platelet reactivity, size and concentration are also known to be altered in some women who develop PE, although the underlying reasons for this have not been determined. In this study we show that STBEV from disease free placenta isolated ex vivo by dual placental perfusion associate rapidly with platelets. We provide evidence that STBEV isolated from normal placentas cause platelet activation and that this is increased with STBEV from PE pregnancies. Furthermore, treatment of platelets with aspirin, currently prescribed for women at high risk of PE to reduce platelet aggregation, also inhibits STBEV-induced reversible aggregation of washed platelets. Increased platelet reactivity as a result of exposure to PE placenta derived STBEVs correlates with increased thrombotic risk associated with PE. These observations establish a possible direct link between the clotting disturbances of PE and dysfunction of the placenta, as well as the known increased risk of thromboembolism associated with this condition.

Concord Grape Juice, cognitive function and driving performance: a 12 week, placebo controlled, randomised, crossover trial in mothers of pre-teen children

Background: Daily consumption of Concord grape juice (CGJ) over three to four months has been shown to improve memory function in adults with mild cognitive impairment, and reduce blood pressure in hypertensive adults. These benefits are likely due to the high concentration of polyphenols in CGJ. Increased stress can impair cognitive function and elevate blood pressure. Thus we examined the potential beneficial effect of CGJ in individuals experiencing somewhat stressful demanding lifestyles. Objective: To examine the effects of twelve weeks’ daily consumption of CGJ on cognitive function, driving performance, and blood pressure in healthy, middle-aged working mothers. Design: Twenty five healthy mothers of pre-teen children, aged 40-50 years, who were employed for > 30 hours/week consumed 12oz (355ml) CGJ (containing 777mg total polyphenols) or an energy, taste and appearance matched placebo daily for twelve weeks according to a randomised, crossover design with a four week washout. Verbal and spatial memory, executive function, attention, blood pressure and mood were assessed at baseline, six weeks and twelve weeks. Immediately following the cognitive battery, a subsample of seventeen females completed a driving performance assessment in the University of Leeds Driving Simulator. The twenty five minute driving task required participants to match the speed and direction of a lead vehicle. Results: Significant improvements in immediate spatial memory and driving performance were observed following CGJ relative to placebo. There was evidence of an enduring effect of CGJ such that participants who received CGJ in arm 1 maintained better performance in the placebo arm. Conclusions: Cognitive benefits associated with chronic consumption of flavonoid-rich grape juice are not exclusive to adults with mild cognitive impairment. Moreover, these cognitive benefits are apparent in complex everyday tasks such as driving. Effects may persist beyond cessation of flavonoid consumption and future studies should carefully consider the length of washout within crossover designs.

Pre-Columbian ring ditch construction and land use on a “chocolate forest island” in the Bolivian Amazon

We present a palaeoecological investigation of pre-Columbian land use in the savannah “forest island” landscape of north-east Bolivian Amazonia. A 5700 year sediment core from La Luna Lake, located adjacent to the La Luna forest island site, was analysed for fossil pollen and charcoal. We aimed to determine the palaeoenvironmental context of pre-Columbian occupation on the site and assess the environmental impact of land use in the forest island region. Evidence for anthropogenic burning and Zea mays L. cultivation began ~2000 cal a BP, at a time when the island was covered by savannah, under drier-than-present climatic conditions. After ~1240 cal a BP burning declined and afforestation occurred. We show that construction of the ring ditch, which encircles the island, did not involve substantial deforestation. Previous estimates of pre-Columbian population size in this region, based upon labour required for forest clearance, should therefore be reconsidered. Despite the high density of economically useful plants, such as Theobroma cacao, in the modern forest, no direct pollen evidence for agroforestry was found. However, human occupation is shown to pre-date and span forest expansion on this site, suggesting that here, and in the wider forest island region, there is no truly pre-anthropogenic ‘pristine’ forest.

The effect of simulated flooding post-anthesis on pre-harvest sprouting and subsequent seed longevity in contrasting rice cultivars

Unpredictable flooding is a major constraint to rice production. It can occur at any growth stage. The effect of simulated flooding post-anthesis on yield and subsequent seed quality of pot-grown rice (Oryza sativa L.) plants was investigated in glasshouses and controlled-environment growth cabinets. Submergence post-anthesis (9-40 DAA) for 3 or 5 days reduced seed weight of japonica rice cv. Gleva, with considerable pre-harvest sprouting (up to 53%). The latter was greater the later in seed development and maturation that flooding occurred. Sprouted seed had poor ability to survive desiccation or germinate normally upon rehydration, whereas the effects of flooding on the subsequent air-dry seed storage longevity (p50) of the non-sprouted seed fraction was negligible. The indica rice cvs IR64 and IR64Sub1 (introgression of submergence tolerance gene Submergence1A-1) were both far more tolerant to flooding post-anthesis than cv. Gleva: four days’ submergence of these two near-isogenic cultivars at 10-40 DAA resulted less than 1% sprouted seeds. The presence of the Sub1A-1 allele in cv. IR64Sub1 was verified by gel electrophoresis and DNA sequencing. It had no harmful effect on loss in seed viability during storage compared with IR64 in both control and flooded environments. Moreover, the germinability and changes in dormancy during seed development and maturation were very similar to IR64. The efficiency of using chemical spray to increase seed dormancy was investigated in the pre-harvest sprouting susceptible rice cv. Gleva. Foliar application of molybdenum at 100 mg L-1 reduced sprouted seeds by 15-21% following 4 days’ submergence at 20-30 DAA. Analyses confirmed that the treatment did result in molybdenum uptake by the plants, and also tended to increase seed abscisic acid concentration. The latter was reduced by submergence and declined exponentially during grain ripening. The selection of submergence-tolerant varieties was more successful than application of molybdenum in reducing pre-harvest sprouting.