Essential variables to consider for an efficient control strategy for invasive plants include dispersion pattern (i.e., satellite or invasion front) and patch expansion rate. These variables were demonstrated for buffelgrass [Pennisetum ciliare (L.) Link], a C4 perennial grass introduced from Africa, which has invaded broadly around the world. The study site was along a roadway in southern Arizona (USA). The P. ciliare plant distributions show the pattern of clumping associated with the satellite (nascent foci) colonization pattern (average nearest neighbor test, z-score −47.2, P<0.01). The distance between patches ranged from 0.743 to 12.8 km, with an average distance between patches of 5.6 km. Median patch expansion rate was 271% over the 3-yr monitoring period versus 136% found in other studies of established P. ciliare patches. Targeting P. ciliare satellite patches as a control strategy may exponentially reduce the areal doubling time, while targeting the largest patches may have less effect on the invasion speed.

Analytical transmission electron microscopy was applied to some authigenic chlorites occurring as grain coatings in sandstones. Compositional variation proved to be relatively slight: all were magnesian chamosites. The coating chlorites were often intimately mixed with extremely fine-grained (0·01–0·2 µm) hematite but analytical ‘contamination’ was avoided because of the very high resolution of both observation (spot location) and analysis. One example of a water-sensitive (‘swelling chlorite’) coating was also studied. This proved to have a very much more variable composition even within a single section. The coating appeared to include both chloritic and vermiculitic components. The effect of this on structural formulae is discussed and a model proposed in which the ‘talc’ layer may be common to both components.

Authigenic chlorites occurring as pore linings in reservoir sandstones have been investigated by XRD and TEM/EDAX. Both methods identified the Ib (β = 90°) polytype. TEM/EDAX analyses suggest that the chlorites are Al-rich, Mg-chamosites with Fe/(Fe + Mg) > 0·47. Octahedral Al exceeds tetrahedral Al, resulting in octahedral totals of less than the theoretical 12·0. Compositions were estimated from XRD data using the equations after Brindley (1961) and Shirozu (1958). XRD-determined compositions are relatively enriched in tetrahedral Al and octahedral Mg, giving Fe/(Fe + Mg) > 0·4 and suggesting that the chlorites are Al-rich clinochlores. XRD estimates plot in the same compositional area as authigenic Ib (β = 90°) chlorites of Hayes (1970), but also within the compositional area of metamorphic chlorites. Caution should be exercised when estimating the composition of sedimentary chlorites by XRD as results appear to overestimate Mg content because of the excess of octahedral R3+ over tetrahedral R3+.

A range of authigenic sedimentary chlorites from sandstones has been studied by analytical transmission electron microscopy. Selected area (single crystal) electron diffraction patterns are of the Ib (β = 90°) polytype confirming the earlier observations of Hayes (1970).

TEM analyses show all samples to be relatively rich in both Al and Fe. In the general formula (Mg,Fe,Al)n [Si8−xAlxO20](OH)16, x varies between 1.5 and 2.6; Fe/(Fe + Mg) between 0.47 and 0.83 and n between 10.80 and 11.54. Octahedral Al is close to 3 in this formulation and Fe2+ predominates over Fe3+. Swelling chlorites have significantly different compositions which are consistent with smectite/chlorite interstratifications.

The Ib (β = 90°) polytype appears to be stable under conditions of moderate to deep burial. It replaces berthierine and swelling chlorites formed at lower temperatures. As commonly seen in grain coatings, however, it precipitates from porewater; solutes probably being contributed from several mineral decomposition reactions.

Extended abstract of a paper presented at Microscopy and Microanalysis 2012 in Phoenix, Arizona, USA, July 29 – August 2, 2012.

Extended abstract of a paper presented at Microscopy and Microanalysis 2011 in Nashville, Tennessee, USA, August 7–August 11, 2011.

A trial of protective efficacy which compared medium–titre Edmonston-Zagreb (EZ) measles vaccine (104.6 p.f.u.) from the age of 4 months with the standard Schwarz (SW) measles vaccine given from the age of 9 months was started in an urban community in Guinea-Bissau in 1985. Because trials of high–titre measles vaccine have found increased mortality among female recipients, we examined whether EZ medium–titre vaccine was associated with any long-term impact on mortality, suppression of T–cells, or growth. The mortality rate ratio over 5 years of follow–up was 1.12 for EZ children compared with children in the standard group (P = 0.63). Seventy–five percent of the children still residing in the area at 5 years of age took part in an immunological and anthropometric examination. There was no difference in T–cell subsets between the two groups. There was no difference in mid–upper–arm circumference, but EZ children were significantly shorter than the children in the standard group. In conclusion, medium–titre EZ was not associated with reduced survival or persistent immunosuppression.

Extended abstract of a paper presented at Microscopy and Microanalysis 2006 in Chicago, Illinois, USA, July 30 – August 3, 2005

The radiation damage properties of synthetic pyrochlore-defect fluorite compounds containing lanthanides on the A-site and Ti, Zr, Sn, and Hf on the B-site have been studied extensively using Kr ion irradiation. Using statistical analysis, we show that the results can be quantified in terms of the critical temperature for amorphization, structural parameters, classical Pauling electronegativity difference, and defect energies. The best current model is able to predict the critical temperature to within about 80 degrees Kelvin. The model indicates that radiation tolerance is correlated with an increase in the X anion coordinate toward the value characteristic of the defect fluorite topology, a smaller unit cell dimension, and lower defect energies. Our analysis also demonstrates that radiation tolerance is promoted by an increase in the Pauling cation-anion electronegativity difference or, in other words, an increase in the ionicity of the chemical bonds. Of the two possible cation sites in ideal pyrochlore, the B-site cation appears to play the major role in bonding. This result is supported, for a subset of pyrochlore compounds, by ab initio calculations, which reveal a correlation between the Mulliken overlap populations of the B-site cation and the critical temperature.

Hollandites with compositions Ba1.2-xCsxMg1.2-x/2Ti6.8+x/2 O16, and Ba1.2-xCsxAl2.4-xTi5.6+xO16 (x=0, 0.1, 0.25) have been synthesised using a modified alkoxide/acetate precursor route. The samples have been sintered using two procedures; hot isostatic pressing and sintering at ambient pressure. X-ray powder diffraction has shown samples from both systems to form tetragonal hollandites, with little change when pressed by both methods. Cs-133 MAS NMR spectra have been recorded showing the chemical shift in Al containing samples to be ∼250ppm, and in Mg hollandites ∼175ppm and 200ppm, with little change when prepared by both methods.

Water from the separation plant at Sullom Voe is discharged into the sea under agreed conditions from a diffuser situated to the north of Calback Ness, close to natural scallop (Pecten maximus) beds.

As part of the arrangements to monitor potential effects of the discharge, Torry Research Station was asked to assess, for petroleum taint, shellfish which would be sampled at intervals from Sullom Voe. To avoid depletion of the natural shellfish beds, queen scallops (Chlamys opercularis) or scallops, whichever were available from other areas, were set out in cages suspended (or on the bottom) 100–1250 m eastwards of the outfall for a period, and then recovered, frozen, and assessed subsequently at the laboratory by a trained taste panel, and compared with the same species unexposed.

The cages were laid on 10 occasions from March 1980 to February 1987. Initially, no petroleum taint was detected. In August 1980 and May 1981, a different flavour, but not recognisable as a petroleum taint, was detected at 800–1000 m from the outfall after three days exposure. In May 1982, 33% of the queen scallops in the cage on the bottom, 100 m south east of the diffuser, were dead after six days exposure, and taint was detected at the threshold level in shellfish in the cage at 300 m. In May 1983, taint and petroleum derived hydrocarbons were detected in the sample from the cage on the bottom, 100 m south east of the diffuser, after seven days exposure. In May 1984, taint was again detected at the bottom, 200 m south east of the outfall, after 10 days exposure.

Enquiries established that the diffuser was not operating with maximum efficiency. Subsequently, monitoring revealed an improvement. Taint assessment proved to be a sensitive detector of petroleum contamination.

The results of chemical analyses for hydrocarbon components in the surface water film, water, sediment traps and sediments are presented for samples collected during the period 1973–78. The n-alkane profiles of these samples are used to characterise the hydrocarbons and to help in determining their origin. The amounts of hydrocarbon present are compared to the estimated inputs of petroleum hydrocarbons from operational losses and accidents based upon analogies with worldwide averages and with data taken from other similar oil terminals. Some conclusions are drawn as to the likely fate of this oil in Sullom Voe.