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Preparation and analysis of testate amoebae in peatland palaeoenvironmental studies
R.K. Booth,M. Lamentowicz,D.J. Charman
Mires and Peat , 2010,
Abstract: The use of testate amoebae in studies of peatland hydrology and palaeohydrology has been increasing, and considerable efforts have been made over the past decade to standardise techniques as much as possible. In this article we briefly describe the common procedures used to collect, prepare and analyse testate amoebae in peat-based studies of palaeohydrology and palaeoclimatology. Although specific methods are dependent on the questions and objectives of individual studies, the methods presented here should serve as a good starting point for peatland palaeoenvironmental applications.
The influence of vegetation on the ITCZ and South Asian monsoon in HadCM3
M. P. McCarthy, J. Sanjay, B. B. B. Booth, K. Krishna Kumar,R. A. Betts
Earth System Dynamics (ESD) & Discussions (ESDD) , 2012, DOI: 10.5194/esd-3-87-2012
Abstract: The role of global vegetation on the large-scale tropical circulation is examined in the version 3 Hadley Centre climate model (HadCM3). Alternative representations of global vegetation cover from observations and a dynamic global vegetation model (DGVM) were used as the land-cover component for a number of HadCM3 experiments under a nominal present day climate state, and compared to the simulations using the standard land cover map of HadCM3. The alternative vegetation covers result in a large scale cooling of the Northern Hemisphere extra-tropics relative to the HadCM3 standard, resulting in a southward shift in the location of the inter-tropical convergence zone (ITCZ). A significant reduction in Indian monsoon precipitation is also found, which is related to a weakening of the South Asian monsoon circulation, broadly consistent with documented mechanisms relating to temperature and snow perturbations in the Northern Hemisphere extra-tropics in winter and spring, delaying the onset of the monsoon. The role of the Northern Hemisphere extra-tropics on tropical climate is demonstrated, with an additional representation of vegetation cover based on DGVM simulated changes in Northern Hemisphere vegetation from the end of the 21st Century. This experiment shows that through similar processes the simulated extra-tropical vegetation changes in the future contribute to a strengthening of the South Asian monsoon in this model. These findings provide renewed motivation to give careful consideration to the role of global scale vegetation feedbacks when looking at climate change, and its impact on the tropical circulation and South Asian monsoon in the latest generation of Earth System models.
Climate-related changes in peatland carbon accumulation during the last millennium
D. J. Charman,D. W. Beilman,M. Blaauw,R. K. Booth
Biogeosciences Discussions , 2012, DOI: 10.5194/bgd-9-14327-2012
Abstract: Peatlands are a major terrestrial carbon store and a persistent natural carbon sink during the Holocene, but there is considerable uncertainty over the fate of peatland carbon in a changing climate. It is generally assumed that higher temperatures will increase peat decay, causing a positive feedback to climate warming and contributing to the global positive carbon cycle feedback. Here we use a new extensive database of peat profiles across northern high latitudes to examine spatial and temporal patterns of carbon accumulation over the past millennium. Opposite to expectations, our results indicate a small negative carbon cycle feedback from past changes in the long-term accumulation rates of northern peatlands. Total carbon accumulated over the last 1000 yr is linearly related to contemporary growing season length and photosynthetically active radiation, suggesting that variability in net primary productivity is more important than decomposition in determining long-term carbon accumulation. Furthermore, northern peatland carbon sequestration rate declines over the climate transition from the Medieval Climate Anomaly (MCA) to the Little Ice Age (LIA), probably because of lower LIA temperatures combined with increased cloudiness suppressing net primary productivity. Other factors including changing moisture status, peatland distribution, fire, nitrogen deposition, permafrost thaw and methane emissions will also influence future peatland carbon cycle feedbacks, but our data suggest that the carbon sequestration rate could increase over many areas of northern peatlands.
(4S,5R,6R)-Methyl 4-hydroxy-4,5-isopropylidenedioxy-4,5,6,7-tetrahydro-1,2,3-triazolo[1,5-a]pyridine-3-carboxylate
Sarah F. Jenkinson,Jennifer R. Fenton,K. Victoria Booth,George W. J. Fleet
Acta Crystallographica Section E , 2009, DOI: 10.1107/s1600536809006357
Abstract: X-ray crystallography confirmed the structure of the title triazole, C11H15N3O5, formed from a single-step reaction of a sugar azide with a brominated ylid. The absolute configuration was determined by the use of d-ribose as the starting material. The six-membered ring is in a half-chair conformation. The crystal structure exists as chains of O—H...O hydrogen-bonded moleclues running parallel to the b axis.
(4S,5R,6R)-Methyl 4-hydroxy-4,5-isopropylidenedioxy-4,5,6,7-tetrahydro-1,2,3-triazolo[1,5-a]pyridine-3-carboxylate. Erratum
Sarah F. Jenkinson,Jennifer R. Fenton,K. Victoria Booth,George W. J. Fleet
Acta Crystallographica Section E , 2009, DOI: 10.1107/s1600536809030529
Abstract: The chemical name of the title compound in the paper by Jenkinson, Fenton, Booth, Fleet & Watkin [Acta Cryst. (2009), E65, o610–o611] is corrected.
High Risk Aortic Valve Replacement – The Challenges of Multiple Treatment Strategies with an Evolving Technology
G Manoharan,J M Jones,K Booth,M McBride,M Spence,R Beattie
- , 2016,
Abstract:
Increased survivin expression contributes to apoptosis-resistance in IPF fibroblasts  [PDF]
Thomas H. Sisson, Toby M. Maher, Iyabode O. Ajayi, Jessie E. King, Peter D.R. Higgins, Adam J. Booth, Rommel L. Sagana, Steven K. Huang, Eric S. White, Bethany B. Moore, Jeffrey C. Horowitz
Advances in Bioscience and Biotechnology (ABB) , 2012, DOI: 10.4236/abb.2012.326085
Abstract: Fibroblasts perform critical functions during the normal host response to tissue injury, but the inappropriate accumulation and persistent activation of these cells results in the development of tissue fibrosis. The mechanisms accounting for the aberrant accumulation of fibroblasts during fibrotic repair are poorly understood, although evidence supports a role for fibroblast resistance to apoptosis as a contributing factor. We have shown that TGF-β1 and endothelin-1 (ET-1), soluble mediators implicated in fibrogenesis, promote fibroblast resistance to apoptosis. Moreover, we recently found that ET-1 induced apoptosis resistance in normal lung fibroblasts through the upregulation of survivin, a member of the Inhibitor of Apoptosis (IAP) protein family. In the current study, we sought to determine the role of survivin in the apoptosis resistance of primary fibroblasts isolated from the lungs of patients with Idiopathic Pulmonary Fibrosis (IPF), a fibrotic lung disease of unclear etiology for which there is no definitive therapy. First, we examined survivin expression in lung tissue from patients with IPF and found that there is robust expression in the fibroblasts residing within fibroblastic foci (the “active” lesions in IPF which correlate with mortality). Next, we show that survivin expression is increased in fibroblasts isolated from IPF lung tissue compared to cells from normal lung tissue. Consistent with a role in fibrogenesis, we demonstrate that TGF-β1 increases survivin expression in normal lung fibroblasts. Finally, we show that inhibition of survivin enhances susceptibility of a subset of IPF fibroblasts to apoptosis. Collectively, these findings suggest that increased survivin expression represents one mechanism contributing an apoptosis-resistant phenotype in IPF fibroblasts.
Universal Dynamic Conductivity and Quantized Visible Opacity of Suspended Graphene
R. R. Nair,P. Blake,A. N. Grigorenko,K. S. Novoselov,T. J. Booth,T. Stauber,N. M. R. Peres,A. K. Geim
Physics , 2008, DOI: 10.1126/science.1156965
Abstract: We show that the optical transparency of suspended graphene is defined by the fine structure constant, alpha, the parameter that describes coupling between light and relativistic electrons and is traditionally associated with quantum electrodynamics rather than condensed matter physics. Despite being only one atom thick, graphene is found to absorb a significant (pi times alpha=2.3%) fraction of incident white light, which is a consequence of graphene's unique electronic structure. This value translates into universal dynamic conductivity G =e^2/4h_bar within a few percent accuracy.
Admissible and Restrained Revision
R. Booth,T. Meyer
Computer Science , 2011, DOI: 10.1613/jair.1874
Abstract: As partial justification of their framework for iterated belief revision Darwiche and Pearl convincingly argued against Boutiliers natural revision and provided a prototypical revision operator that fits into their scheme. We show that the Darwiche-Pearl arguments lead naturally to the acceptance of a smaller class of operators which we refer to as admissible. Admissible revision ensures that the penultimate input is not ignored completely, thereby eliminating natural revision, but includes the Darwiche-Pearl operator, Nayaks lexicographic revision operator, and a newly introduced operator called restrained revision. We demonstrate that restrained revision is the most conservative of admissible revision operators, effecting as few changes as possible, while lexicographic revision is the least conservative, and point out that restrained revision can also be viewed as a composite operator, consisting of natural revision preceded by an application of a "backwards revision" operator previously studied by Papini. Finally, we propose the establishment of a principled approach for choosing an appropriate revision operator in different contexts and discuss future work.
Macroscopic graphene membranes and their extraordinary stiffness
T. J. Booth,P. Blake,R. R. Nair,D. Jiang,E. W. Hill,U. Bangert,A. Bleloch,M. Gass,K. S. Novoselov,M. I. Katsnelson,A. K. Geim
Physics , 2008, DOI: 10.1021/nl801412y
Abstract: The properties of suspended graphene are currently attracting enormous interest, but the small size of available samples and the difficulties in making them severely restrict the number of experimental techniques that can be used to study the optical, mechanical, electronic, thermal and other characteristics of this one-atom-thick material. Here we describe a new and highly-reliable approach for making graphene membranes of a macroscopic size (currently up to 100 microns in diameter) and their characterization by transmission electron microscopy. In particular, we have found that long graphene beams supported by one side only do not scroll or fold, in striking contrast to the current perception of graphene as a supple thin fabric, but demonstrate sufficient stiffness to support extremely large loads, millions of times exceeding their own weight, in agreement with the presented theory. Our work opens many avenues for studying suspended graphene and using it in various micromechanical systems and electron microscopy.
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