Stable oxygen isotopes in Irish oaks: potential for reconstructing local and regional climate

The long Irish oak tree-ring chronology, developed for archaeological dating and radiocarbon calibration, is the longest of any in northwest maritime Europe, spanning most of the Holocene (7,272 years). Unfortunately, the rings widths do not carry a strong climate signal and the record hasnever been satisfactorily applied for dendroclimatic reconstruction. This pilot study explores the potential for extracting a climate signal from Irish oaks by comparing the stable oxygen isotopes ratios from 10 oak tree cores (Quercus robur and Quercus petraea L.) collected across the Armagh region of NE Ireland with local and regional climatic and stable isotopic data. Statistically significant correlations between isotope ratios and the amount of summer precipitation (r = -0.44) point to the isotopic composition of summer rainfall as the dominant signal. Including the Armagh data into an extended regional oxygen isotope series did not reduce the correlation coefficient with regional precipitation (r = -0.68, p < 0.01). Correlations of this magnitude in dendro-hydroclimatology are typically restricted to trees growing at their ecological limits. This research suggests that there is considerable potential for including living trees and ancient timbers from Ireland into a regional composite to reconstruct the summer hydroclimate of Britain and Ireland

Sustainability

We have to learn to live on our planet, and that’s a job that involves educators

Invitational leadership

Leaders need to be constantly reflecting, analysing their actions and words to see if they are inviting or suppressing leadership in others

Seeing things differently

The metaphors we use can help us articulate new mental models that will assist our school Community to understand the need for, and pathways to, change

Educational leaders

David Loader acknowledges his elders, those who have helped him to formulate His views on epistemology, learning, schooling, curriculum and pedagogy, and asks who you would nominate as your elders in education

A small temperature rise may contribute towards the apparent induction by microwaves of heatshock gene expression in the nematode Caenorhabditis elegans

We have previously reported that low-intensity microwave exposure (0.75-1.0 GHz CW at 0.5 W; SAR 4-40 mW kg-1) can induce an apparently non-thermal heat-shock response in Caenorhabditis elegans worms carrying hsp16-1::reporter genes. Using matched copper TEM cells for both sham and exposed groups, we can detect only modest reporter induction in the latter (15-20% after 2.5 h at 26°C, rising to ~50% after 20 h). Traceable calibration of our copper TEM cell by the National Physical Laboratory (NPL) reveals significant power loss within the cell (8.5% at 1.0 GHz), accompanied by slight heating of exposed samples (~0.3°C at 1.0 W). Thus exposed samples are in fact slightly warmer (by ≤0.2°C at 0.5 W) than sham controls. Following NPL recommendations, our TEM cell design was modified with the aim of reducing both power loss and consequent heating. In the modified silver-plated cell, power loss is only 1.5% at 1.0 GHz, and sample warming is reduced to ~ 0.15°C at 1.0 W (i.e. ≤ 0.1°C at 0.5 W). Under sham:sham conditions, there is no difference in reporter expression between the modified silverplated TEM cell and an unmodified copper cell. However, worms exposed to microwaves (1.0 GHz and 0.5 W) in the silver-plated cell also show no detectable induction of reporter expression relative to sham controls in the copper cell. Thus the 20% “microwave induction” observed using two copper cells may be caused by a small temperature difference between sham and exposed conditions. In worms incubated for 2.5 h at 26.0, 26.2 and 27.0°C (with no microwave field), there is a consistent and significant increase in reporter expression between 26.0 and 26.2°C (by ~20% in each of 6 independent runs), but paradoxically expression levels at 27.0°C are similar to those seen at 26.0°C. This surprising result is in line with other evidence pointing towards complex regulation of hsp16-1 gene expression across the sub-heat-shock range of 25-27.5°C in C. elegans. We conclude that our original interpretation of a non-thermal effect of microwaves cannot be sustained; at least part of the explanation appears to be thermal

Low-intensity microwave irradiation does not substantially alter gene expression in late larval and adult Caenorhabditis elegans.

Reports that low-intensity microwave radiation induces heat-shock reporter gene expression in the nematode, Caenorhabditis elegans, have recently been reinterpreted as a subtle thermal effect caused by slight heating. This study used a microwave exposure system (1.0 GHz, 0.5 W power input; SAR 0.9-3 mW kg-1 for 6-well plates) that minimises temperature differentials between sham and exposed conditions (≤0.1 °C). Parallel measurement and simulation studies of SAR distribution within this exposure system are presented. We compared 5 Affymetrix gene-arrays of pooled triplicate RNA populations from sham-exposed L4/adult worms against 5 gene-arrays of pooled RNA from microwave-exposed worms (taken from the same source population in each run). No genes showed consistent expression changes across all 5 comparisons, and all expression changes appeared modest after normalisation (≤ 40% up- or down-regulated). The number of statistically significant differences in gene expression (846) was less than the false-positive rate expected by chance (1131). We conclude that the pattern of gene expression in L4/adult C. elegans is substantially unaffected by low-intensity microwave radiation; the minor changes observed in this study could well be false positives. As a positive control, we compared RNA samples from N2 worms subjected to a mild heat-shock treatment (30ºC) against controls at 26 ºC (2 gene arrays per condition). As expected, heat-shock genes are strongly up-regulated at 30ºC, particularly an hsp-70 family member (C12C8.1) and hsp-16.2 . Under these heat-shock conditions, we confirmed that an hsp-16.2::GFP transgene was strongly up-regulated, whereas two non-heat-inducible transgenes (daf-16::GFP; cyp-34A9::GFP) showed little change in expression

A framework for accessible m-government implementation

The great popularity and rapid diffusion of mobile technologies at worldwide level has also been recognised by the public sector, leading to the creation of m-government. A major challenge for m-government is accessibility – the provision of an equal service to all citizens irrespective of their psychical, mental or technical capabilities. This paper sketches the profiles of six citizen groups: Visually Impaired, Hearing Impaired, Motor Impaired, Speech Impaired, Cognitive Impaired and Elderly. M-government examples that target the aforementioned groups are discussed and a framework for accessible m-government implementation with reference to the W3C Mobile Web Best Practices is proposed