Ultrafast Non-Radiative Decay of Gas-Phase Nucleosides

The ultrafast photo-physical properties of DNA are crucial in providing a stable basis for life. Although the DNA bases efficiently absorb ultraviolet (UV) radiation, this energy can be dissipated to the surrounding environment by the rapid conversion of electronic energy to vibrational energy within about a picosecond. The intrinsic nature of this internal conversion process has previously been demonstrated through gas phase experiments on the bases, supported by theoretical calculations. De-excitation rates appear to be accelerated when individual bases are hydrogen bonded to solvent molecules or their complementary Watson-Crick pair. In this paper, the first gas-phase measurements of electronic relaxation in DNA nucleosides following UV excitation are reported. Using a pump-probe ionization scheme, the lifetimes for internal conversion to the ground state following excitation at 267 nm are found to be reduced by around a factor of two for adenosine, cytidine and thymidine compared with the isolated bases. These results are discussed in terms of a recent proposition that a charge transfer state provides an additional internal conversion pathway mediated by proton transfer through a sugar to base hydrogen bond.

Size-balanced community reorganization in response to nutrients and warming

It is widely accepted that global warming will adversely affect ecological communities. As ecosystems are simultaneously exposed to other anthropogenic influences, it is important to address the effects of climate change in the context of many stressors. Nutrient enrichment might offset some of the energy demands that warming can exert on organisms by stimulating growth at the base of the food web. It is important to know whether indirect effects of warming will be as ecologically significant as direct physiological effects. Declining body size is increasingly viewed as a universal response to warming, with the potential to alter trophic interactions. To address these issues, we used an outdoor array of marine mesocosms to examine the impacts of warming, nutrient enrichment and altered top-predator body size on a community comprised of the predator (shore crab Carcinus maenas), various grazing detritivores (amphipods) and algal resources. Warming increased mortality rates of crabs, but had no effect on their moulting rates. Nutrient enrichment and warming had near diametrically opposed effects on the assemblage, confirming that the ecological effects of these two stressors can cancel each other out. This suggests that nutrient-enriched systems might act as an energy refuge to populations of species under metabolic constraints due to warming. While there was a strong difference in assemblages between mesocosms containing crabs compared to mesocosms without crabs, decreasing crab size had no detectable effect on the amphipod or algal assemblages. This suggests that in allometrically balanced communities, the expected long-term effect of warming (declining body size) is not of similar ecological consequence to the direct physiological effects of warming, at least not over the six week duration of the experiment described here. More research is needed to determine the long-term effects of declining body size on the bioenergetic balance of natural communities.

MRZ-99030 – a novel modulator of Aβ aggregation: II – reversal of Aβ oligomer-induced deficits in long-term potentiation (LTP) and cognitive performance in rats and mice.

β-amyloid1-42 (Aβ1-42) is a major endogenous pathogen underlying the aetiology of Alzheimer's disease (AD). Recent evidence indicates that soluble Aβ oligomers, rather than plaques, are the major cause of synaptic dysfunction and neurodegeneration. Small molecules that suppress Aβ aggregation, reduce oligomer stability or promote off-pathway non-toxic oligomerization represent a promising alternative strategy for neuroprotection in AD. MRZ-99030 was recently identified as a dipeptide that modulates Aβ1-42 aggregation by triggering a non-amyloidogenic aggregation pathway, thereby reducing the amount of intermediate toxic soluble oligomeric Aβ species. The present study evaluated the relevance of these promising results with MRZ-99030 under pathophysiological conditions i.e. against the synaptotoxic effects of Aβ oligomers on hippocampal long term potentiation (LTP) and two different memory tasks. Aβ1-42 interferes with the glutamatergic system and with neuronal Ca2+ signalling and abolishes the induction of LTP. Here we demonstrate that MRZ-99030 (100–500 nM) at a 10:1 stoichiometric excess to Aβ clearly reversed the synaptotoxic effects of Aβ1-42 oligomers on CA1-LTP in murine hippocampal slices. Co-application of MRZ-99030 also prevented the two-fold increase in resting Ca2+ levels in pyramidal neuron dendrites and spines triggered by Aβ1-42 oligomers. In anaesthetized rats, pre-administration of MRZ-99030 (50 mg/kg s.c.) protected against deficits in hippocampal LTP following i.c.v. injection of oligomeric Aβ1-42. Furthermore, similar treatment significantly ameliorated cognitive deficits in an object recognition task and under an alternating lever cyclic ratio schedule after the i.c.v. application of Aβ1-42 and 7PA2 conditioned medium, respectively. Altogether, these results demonstrate the potential therapeutic benefit of MRZ-99030 in AD.

Species composition of coastal dune vegetation in Scotland has proved resistant to climate change over a third of a century

Climate change is expected to have an impact on plant communities as increased temperatures are expected to drive individual species' distributions polewards. The results of a revisitation study after c. 34years of 89 coastal sites in Scotland, UK, were examined to assess the degree of shifts in species composition that could be accounted for by climate change. There was little evidence for either species retreat northwards or for plots to become more dominated by species with a more southern distribution. At a few sites where significant change occurred, the changes were accounted for by the invasion, or in one instance the removal, of woody species. Also, the vegetation types that showed the most sensitivity to change were all early successional types and changes were primarily the result of succession rather than climate-driven changes. Dune vegetation appears resistant to climate change impacts on the vegetation, either as the vegetation is inherently resistant to change, management prevents increased dominance of more southerly species or because of dispersal limitation to geographically isolated sites.

The PREDICTS database: a global database of how local terrestrial biodiversity responds to human impacts

Biodiversity continues to decline in the face of increasing anthropogenic pressures such as habitat destruction, exploitation, pollution and introduction of alien species. Existing global databases of species’ threat status or population time series are dominated by charismatic species. The collation of datasets with broad taxonomic and biogeographic extents, and that support computation of a range of biodiversity indicators, is necessary to enable better understanding of historical declines and to project – and avert – future declines. We describe and assess a new database of more than 1.6 million samples from 78 countries representing over 28,000 species, collated from existing spatial comparisons of local-scale biodiversity exposed to different intensities and types of anthropogenic pressures, from terrestrial sites around the world. The database contains measurements taken in 208 (of 814) ecoregions, 13 (of 14) biomes, 25 (of 35) biodiversity hotspots and 16 (of 17) megadiverse countries. The database contains more than 1% of the total number of all species described, and more than 1% of the described species within many taxonomic groups – including flowering plants, gymnosperms, birds, mammals, reptiles, amphibians, beetles, lepidopterans and hymenopterans. The dataset, which is still being added to, is therefore already considerably larger and more representative than those used by previous quantitative models of biodiversity trends and responses. The database is being assembled as part of the PREDICTS project (Projecting Responses of Ecological Diversity In Changing Terrestrial Systems – www.predicts.org.uk). We make site-level summary data available alongside this article. The full database will be publicly available in 2015.

To Hell with Herbert Read

Freee write manifestos by taking a pencil (or a laptop) to an historical text, usually belonging to the entwined traditions of the avant-garde and political activism. Sometimes, as Tristan Tzara advised, we choose the text according to its length, while other times, such as in this instance, we selected the text according to the conditions of the invitation that triggered the writing of the manifesto. Our manifesto ‘To Hell with Herbert Read’ was written originally as a contribution to a conference held in Manchester that took its title from Herbert Read’s book ‘To Hell with Culture’. ‘To Hell with Culture’ is a book that cuts itself off from the world whereas ‘To Hell with Herbert Read’ relocates Read’s book in a world of cultural, social, economic and political actualities that are part of common experience. Read rejects culture because he thinks it is a useless, wasteful, elitist, puffed-up, decorative supplement to the functional, factual, palpable, purposeful world of things. He is a positivist kind of modernist who presents himself as the opposite, an enemy of the status quo. He is an anarchist of a particularly bourgeois hue: he wants us all to have decent pots and pans, not the inferior ones that are supplied by market forces cheaply. Rather than taking his aim precisely to target the dominant forces of his day - the industrial capitalists and their financiers - he rejects the world and all its inhabitants. He not only despises elitist culture but popular culture too.

To Hell with Herbert Read

Freee write manifestos by taking a pencil (or a laptop) to an historical text, usually belonging to the entwined traditions of the avant-garde and political activism. Sometimes, as Tristan Tzara advised, we choose the text according to its length, while other times, such as in this instance, we selected the text according to the conditions of the invitation that triggered the writing of the manifesto. Our manifesto ‘To Hell with Herbert Read’ was written originally as a contribution to a conference held in Manchester that took its title from Herbert Read’s book ‘To Hell with Culture’. ‘To Hell with Culture’ is a book that cuts itself off from the world whereas ‘To Hell with Herbert Read’ relocates Read’s book in a world of cultural, social, economic and political actualities that are part of common experience. Read rejects culture because he thinks it is a useless, wasteful, elitist, puffed-up, decorative supplement to the functional, factual, palpable, purposeful world of things. He is a positivist kind of modernist who presents himself as the opposite, an enemy of the status quo. He is an anarchist of a particularly bourgeois hue: he wants us all to have decent pots and pans, not the inferior ones that are supplied by market forces cheaply. Rather than taking his aim precisely to target the dominant forces of his day - the industrial capitalists and their financiers - he rejects the world and all its inhabitants. He not only despises elitist culture but popular culture too.

The Contemporary Group, October 24, 1979

Concert program for The Contemporary Group, October 24, 1979

CarolFest 2008, December 2, 2008

Concert Program for CarolFest 2008, December 2, 2008

1969-70 Men's Basketball

Pictured here from left to right: Back Row - Les Korchok (Coach), Ken Cripps, Mike McGinnis, Bill Butler, Tim McKillop, Gary Jellum, Fred Kovacs (Manager). Front Row - Jim Leach, Wally Dick, Bob Tatti, Paul Zutautas, Tom Kearney (Trainer). Kneeling - Dave Luff, Dave Brent. Missing - Bill Levesque.

Cross Country Team (1970-71)

From Left to Right: Terry Neal, Doug Bowers, Art Wiebe, Gord Merrill, Dave Viney