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11.
Top‐down control of species distributions: feral cats driving the regional extinction of a threatened rodent in northern Australia 下载免费PDF全文
12.
Graeme W. Bourd t David Baird Geoff A. Hurrell Meindert D. De Jong 《Biocontrol Science and Technology》2006,16(4):345-358
Variation in the width of 'safety zones' for sheep and dairy pasture treated with a Sclerotinia sclerotiorum (Lib.) de Bary-based mycoherbicide was quantified using 10 years of climate data from each of five regions in New Zealand. Acceptable and risk-averse zones were defined as the maximum distances in any direction from a treated pasture where 'added:natural' ratios of air-borne S. sclerotiorum spores are 1:1 and 1:10, respectively. The 10-year mean 1:1 safety zone had zero width for sheep pasture at all locations, and was at most, 50 m wide for dairy pasture. The width of the 10-year mean 1:10 zone varied regionally from 314 to 443 m for sheep and from 175 to 280 m for dairy pasture, and the 90th percentile 1:10 zones were up to 41% wider. Linear relationships between safety zone width and mean wind speed were evident and these could be used to derive region-specific safety zones. 相似文献
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Sarah J. Smith Christopher J. Noble Randahl C. Palmer Graeme R. Hanson Gerhard Schenk Lawrence R. Gahan Mark J. Riley 《Journal of biological inorganic chemistry》2008,13(4):499-510
A binuclear copper complex, [Cu2(BPMP)(OAc)2][ClO4]·H2O, has been prepared using the binucleating ligand 2,6-bis[bis(pyridin-2-ylmethylamino)methyl]-4-methylphenol (H-BPMP). The
X-ray crystal structure reveals the copper centers to have a five-coordinate square pyramidal geometry, with the acetate ligands
bound terminally. The bridging phenolate occupies the apical position of the square-based pyramids and magnetic susceptibility,
electron paramagnetic resonance (EPR) and variable-temperature variable-field magnetic circular dichroism (MCD) measurements
indicate that the two centers are very weakly antiferromagnetically coupled (J = −0.6 cm−1). Simulation of the dipole–dipole-coupled EPR spectrum showed that in solution the Cu–O–Cu angle was increased from 126°
to 160° and that the internuclear distance was larger than that observed crystallographically. The high-resolution spectroscopic
information obtained has been correlated with a detailed ligand-field analysis to gain insight into the electronic structure
of the complex. Symmetry arguments have been used to demonstrate that the sign of the MCD is characteristic of the tetragonally
elongated environment. The complex also displays catecholase activity (k
cat = 15 ± 1.5 min−1, K
M = 6.4 ± 1.8 mM), which is compared with other dicopper catechol oxidase models.
Electronic supplementary material The online version of this article (doi:) contains supplementary material, which is available to authorized users. 相似文献
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Alexander F. Arendsen Jonathan Hadden Graeme Card Alan S. McAlpine Susan Bailey Vjacheslav Zaitsev Elizabeth H. M. Duke P. F. Lindley Monika Kröckel Alfred X. Trautwein Martinus C. Feiters John M. Charnock C. David Garner Sophie J. Marritt Andrew J. Thomson Ingeborg M. Kooter Michael K. Johnson Willy A. M. van den Berg Walter M. A. M. van Dongen W. R. Hagen 《Journal of biological inorganic chemistry》1998,3(1):81-95
The three-dimensional structure of the native "putative prismane" protein from Desulfovibrio vulgaris (Hildenborough) has been solved by X-ray crystallography to a resolution of 1.72?Å. The molecule does not contain a [6Fe-6S] prismane cluster, but rather two 4Fe clusters some 12?Å apart and situated close to the interfaces formed by the three domains of the protein. Cluster 1 is a conventional [4Fe-4S] cubane bound, however, near the N-terminus by an unusual, sequential arrangement of four cysteine residues (Cys 3, 6, 15, 21). Cluster 2 is a novel 4Fe structure with two μ2-sulfido bridges, two μ2-oxo bridges, and a partially occupied, unidentified μ2 bridge X. The protein ligands of cluster 2 are widely scattered through the second half of the sequence and include three cysteine residues (Cys 312, 434, 459), one persulfido-cysteine (Cys 406), two glutamates (Glu 268, 494), and one histidine (His 244). With this unusual mixture of bridging and external type of ligands, cluster 2 is named the "hybrid" cluster, and its asymmetric, open structure suggests that it could be the site of a catalytic activity. X-ray absorption spectroscopy at the Fe K-edge is readily interpretable in terms of the crystallographic model when allowance is made for volume contraction at 10?K; no Fe··Fe distances beyond 3.1?Å could be identified. EPR, Mössbauer and MCD spectroscopy have been used to define the oxidation states and the magnetism of the clusters in relation to the crystallographic structure. Reduced cluster 1 is a [4Fe-4S]1+ cubane with S?=?3/2; it is the first biological example of a "spin-admixed" iron-sulfur cluster. The hybrid cluster 2 has four oxidation states from (formally) all FeIII to three FeII plus one FeIII. The four iron ions are exchange coupled resulting in the system spins S?=?0, 9/2, 0 (and 4), 1/2, respectively, for the four redox states. Resonance Raman spectroscopy suggests that the bridging ligand X which could not be identified unambiguously in the crystal structure is a solvent-exchangeable oxygen. 相似文献
17.
Chris Kypridemos Piotr Bandosz Graeme L. Hickey Maria Guzman-Castillo Kirk Allen Iain Buchan Simon Capewell Martin O’Flaherty 《PloS one》2015,10(4)
Background
Serum total cholesterol is one of the major targets for cardiovascular disease prevention. Statins are effective for cholesterol control in individual patients. At the population level, however, their contribution to total cholesterol decline remains unclear. The aim of this study was to quantify the contribution of statins to the observed fall in population mean cholesterol levels in England over the past two decades, and explore any differences between socioeconomic groups.Methods and Findings
This is a modelling study based on data from the Health Survey for England. We analysed changes in observed mean total cholesterol levels in the adult England population between 1991-92 (baseline) and 2011-12. We then compared the observed changes with a counterfactual ‘no statins’ scenario, where the impact of statins on population total cholesterol was estimated and removed. We estimated uncertainty intervals (UI) using Monte Carlo simulation, where confidence intervals (CI) were impractical. In 2011-12, 13.2% (95% CI: 12.5-14.0%) of the English adult population used statins at least once per week, compared with 1991-92 when the proportion was just 0.5% (95% CI: 0.3-1.0%). Between 1991-92 and 2011-12, mean total cholesterol declined from 5.86 mmol/L (95% CI: 5.82-5.90) to 5.17 mmol/L (95% CI: 5.14-5.20). For 2011-12, mean total cholesterol was lower in more deprived groups. In our ‘no statins’ scenario we predicted a mean total cholesterol of 5.36 mmol/L (95% CI: 5.33-5.40) for 2011-12. Statins were responsible for approximately 33.7% (95% UI: 28.9-38.8%) of the total cholesterol reduction since 1991-92. The statin contribution to cholesterol reduction was greater among the more deprived groups of women, while showing little socio-economic gradient among men.Conclusions
Our model suggests that statins explained around a third of the substantial falls in total cholesterol observed in England since 1991. Approximately two thirds of the cholesterol decrease can reasonably be attributed non-pharmacological determinants. 相似文献18.
James P. Wells Graeme A. Wood Georgeianna Tebbetts 《Primates; journal of primatology》1977,18(2):417-434
In this study, one positional mode, the vertical leap, is selected from the larger repertoire of habitual behaviors of whichCercopithecus aethiops sabaeus is capable, and is quantitatively analyzed. A cinematographic biomechanical analysis of the vertical leap provides a view
of the kinematics (time-space properties of the leap) as well as the kinetics (or force properties) of the leap. These are
then discussed with regard to anatomical potential. The analysis elucidates three distinct phases of motion during which the
moving body segments linked via their connecting joints, affect one another in the production of the leap. The total positional
adaptation ofC. a. sabaeus may only be determined after similar analyses are performed for all postural and locomotor modes. The present detailed analysis
of vertical leaping is intended to present data for this one positional mode found to be of primary importance in the arboreal
environment and in moving from the ground into the trees. In addition a methodology is illustrated for application in similar
primate positional studies.
A version of this paper was presented at the 43rd Annual Meeting of the American Association of Physical Anthropologists (March,
1974). This research was partially supported by Sigma Xi Grant-in-Aid of Research, Behavioral Science Foundation Fellowship. 相似文献
19.