Testing solar forcing of pervasive Holocene climate cycles

The temporal and spatial extent of Holocene climate change is an area of considerable uncertainty, with solar forcing recently proposed to be the origin of cycles identified in the North Atlantic region. To address these issues we have developed an annually resolved record of changes in Irish bog tree populations over the last 7468 years which, together with radiocarbon-dated bog and lake-edge populations, extend the dataset back to 9000 yr ago. The Irish trees underpin the internationally accepted radiocarbon calibration curve, used to derive a proxy of solar activity, and allow us to test solar forcing of Holocene climate change. Tree populations and age structures provide unambiguous evidence of major shifts in Holocene surface moisture, with a dominant cyclicity of 800 yr, similar to marine cycles in the North Atlantic, indicating significant changes in the latitude and intensity of zonal atmospheric circulation across the region. The cycles, however, are not coherent with changes in solar activity (both being on the same absolute timescale), indicating that Holocene North Atlantic climate variability at the millennial and centennial scale is not driven by a linear response to changes in solar activity.

Cell polarity: Scaffold proteins par excellence

Par proteins are involved in determining cellular asymmetry. Recent studies have identified one of these proteins, Par6, as a key regulator of cell polarity and transformation via its interactions with small GTPases and atypical forms of protein kinase C.

Media coverage of sustainable development issues – attention cycles or punctuated equilibrium?

Over the last two decades there has been a marked change in the way that the public perceives environmental issues and the concepts associated with sustainable development. Few would argue that this has moved into the mainstream of public consciousness. Coverage of sustainability related concepts within the media, as illustrated by a sample of 112 worldwide newspapers, shows a clear upward trajectory. Taking the example of climate change and sustainable development this paper explores this increasing coverage, and arguably awareness of, sustainability concepts and considers parallels with the concepts of punctuated equilibrium and issue-attention cycles.

PAR-2 Regulates Dental Pulp Inflammation Associated with Caries

Protease-activated receptors (PARs) are G-protein-coupled receptors that are activated enzymatically by proteolysis of an N-terminal domain. The cleavage and activation of PARs by serine proteases represent a novel mechanism by which such enzymes could influence the host inflammatory response. The aim of this study was to determine whether PAR-2 expression and activation were increased in dental caries. Using immunohistochemistry, we showed PAR-2 to be localized to pulp cells subjacent to caries lesions, but minimally expressed by healthy pulp tissue. Trypsin and the PAR-2 agonist (PAR2-AP) activated PAR-2 in an in vitro functional assay. Endogenous molecules present in pulp cell lysates from carious teeth specifically activated PAR-2, but those from healthy teeth failed to do so. The activation of PAR-2 in vitro was shown to increase the expression of the pro-inflammatory mediator cyclo-oxygenase-2 (COX-2), providing a mechanism whereby PAR-2 could modulate pulpal inflammation.

Note on 'Growth, Cycles, and Stabilization Policy'

This note presents an analysis which generalizes the results reached by Blackburn and Pelloni (2005) on the relationship between short-term stabilization policy and long-term growth by considering both deliberate (internal) and serendipitous (external) learning mechanisms for productivity growth.

Cell cycles and endocycles in the model brown seaweed, Ectocarpus siliculosus

The recent announcement of the first genome sequence of a brown macroalga, the filamentous Ectocarpus, has been accompanied by a number of companion papers in New Phytologist. In a paper which contributes to this special issue, we classified the core cell cycle components of Ectocarpus, comparing them to the previously studied cell cycle components of diatoms. We then carried out fluorescence microscopy experiments to show that the Ectocarpus cell cycle could be deregulated during early development to give endopolyploid adults. We discuss here how our findings complement recent studies on endopolyploidy in plant and algal systems.