The lower Mississippian Ballagan Formation of northern Britain is one of only two successions worldwide to yield the earliest known tetrapods with terrestrial capability following the end-Devonian mass extinction event. Studies of the sedimentary environments and habitats in which these beasts lived have been an integral part of a major research project into how, why and under what circumstances this profound step in the evolution of life on Earth occurred. Here, a new palaeogeographic map is constructed from outcrop data integrated with new and archived borehole material. The map shows the extent of a very low-relief coastal wetland developed along the tropical southern continental margin of Laurussia. Coastal floodplains in the Midland Valley and Tweed basins were separated from the marginal marine seaway of the Northumberland–Solway Basin to the south by an archipelago of more elevated areas. A complex mosaic of sedimentary environments was juxtaposed, and included fresh and brackish to saline and hypersaline lakes, a diverse suite of floodplain palaeosols and a persistent fluvial system in the east of the region. The strongly seasonal climate led to the formation of evaporite deposits alternating with flooding events, both meteoric and marine. Storm surges drove marine floods from the SW into both the western Midland Valley and Northumberland–Solway Basin; marine water also flooded into the Tweed Basin and Tayside in the east. The Ballagan Formation is a rare example in the geological record of a tropical, seasonal coastal wetland that contains abundant, small-scale evaporite deposits. The diverse sedimentary environments and palaeosol types indicate a network of different terrestrial and aquatic habitats in which the tetrapods lived.

Bettertonite, [Al6(AsO4)3(OH)9(H2O)5]•11H2O and penberthycroftite, [Al6(AsO4)3(OH)9(H2O)5].8H2O, two new minerals from the Penberthy Croft mine, Cornwall, have flexible layer structures based on corner-connected heteropolyhedral columns. Their response to dehydration on heating was studied using in situ synchrotron powder X-ray diffraction at temperatures in the range -53 to 157°C. The bettertonite sample transforms to penberthycroftite in a narrow temperature range of 67 to 97°C with a large (8%) contraction of the layer separation and a 6 Å sliding of adjacent layers relative to each other. Above 100°C a second phase transition occurs to a DL (displaced layer) phase, involving another 8% inter-layer contraction combined with a rotation of the columns. On heating the penberthycroftite sample the phase transition to the DL phase occurs at a lower temperature of ∼80°C. The DL phase is stable to a temperature of ∼120°C. At higher temperatures, increased rotation of the columns is accompanied by a progressive amorphization of the sample. Bettertonite, penberthycroftite and the DL phase exhibit negative thermal expansion (NTE) along all three axes with large NTE coefficients, of the order of-100 x 10 -6 °C-1.

Cahal Tok (Place of Flint) is a limestone rise with some structural evidence, associated with the previously designated LDF Chert Site, close to the ceremonial center of El Pilar. Excavations uncovered evidence that during the Late Classic period, specialized flintknappers produced bifaces, primarily chert axes, at the Cahol Tok locus, first on a cleared limestone shelf then on a prepared cobble platform. Small flakes remained in situ whereas much of the larger debris was deposited to the east off the edge of the platform and into the LDF debitage dump. The identification of a specialized manufacturing locale near the ceremonial precinct of a major center is unusual in Maya archaeology. Central control of an important industry may be implied, although knapping could equally well be organized more independently. We expect that small industrial areas are actually present at most large sites, but may often be difficult to recognize.

Objectives: This study sought to identify potential predictive variables of death within 6 months in patients with advanced AIDS.

Methods: Investigators enrolled a consecutive series of patients with advanced AIDS admitted to a skilled nursing facility in New York City over a 1-year period. Demographic, clinical, laboratory, and outcome data were abstracted from medical records using a standardized data collection instrument.

Results: Of the 152 patients enrolled during the study period, 61 patients (40%) died within 6 months from date of admission. Serum albumin, percent deviation from ideal body weight, and number of comorbidities at the time of admission proved to be the best combination of predictors of death within 6 months.

Significance of results: The decrease in AIDS mortality over the past decade, along with an increase in prevalence due to longer survival, has been attributed primarily to the successful use of highly active antiretroviral therapy (HAART). HAART regimens, however, can also produce both short-term adverse effects and long-term complications. The prognostic model developed by this study may be useful in guiding treatment decisions in patients with advanced AIDS for whom a more palliative care plan may be sought.

The Amery Ice Shelf Ocean Research (AMISOR) project aims to examine and quantify processes involved in the interaction between the ice shelf, the interior grounded ice and the oceanic water masses that circulate beneath it. Two boreholes were melted through the shelf, within 100 km of the calving front, to access the ocean cavity. One (AM02) was at a site where it was believed that basal melt was occurring, and the other (AM01) was in a region with accreted marine ice. At both sites the summertime ocean structure revealed meltwater-modified boundary layers up to 100 m thick immediately beneath the shelf. Salinity and temperature data in the upper cavity at AM02 showed a strong seasonal cycle as a result of a combination of ice-shelf basal melt, and the intrusion of ocean water masses modified by sea-ice processes in Prydz Bay. At AM01, a 200m thick layer of marine ice underlay the meteoric ice, and showed an increase in salinity and decrease in stable-isotope fractionation with depth. The lowest 100m of marine ice was highly permeable, with a rectangular banded textural facies. Other preliminary results from this study are also reported.

Due to their exceptional thermal properties, single-wall carbon nanotubes (SWNT) are considered as very promising filler materials for improving the thermal conductivity of conventional polymers. We carefully investigated the thermal conductivity of SWNT/PMMA nanocomposites with SWNT loading in the range up to10 wt% using the comparative technique. The samples were prepared by coagulation method. We demonstrated moderate improvement in the composites’ thermal conductivity of about 250% at 10wt%. The experimental results were analyzed using the versatile Nielsen model, which takes into account many important factors, like the fillers aspect ratio and maximum packing fraction. The aspect ratio of SWNT material used to prepare our composites was determined by AFM and careful image analysis in order to use it as an input parameter in the Nielsen model. We obtained good agreement between our experimental results and the predictions of the Nielsen model. Based on our analysis we concluded that higher aspect ratio of filler material was needed to achieve better improvement in the composites thermal conductivities. One should also take steps in order to improve the thermal contact between the SWNT network and the matrix material.

Solution deposition processes for the production of thin multi-element metal oxide films continue with great interest and varied success. Solution deposition via either sol-gel or MOD (Metal Organic Decomposition) methods are of interest due to the ability to produce a wide variety of compositional products at low capital investment cost. The sol-gel method generally uses hydrolytically sensitive metal alkoxides as the starting materials. Manipulation of the reagents and different hydrolysis rates for multi-element mixtures are issues. The MOD method utilizes large organic acid metal salts as the starting materials. In general, MOD solutions are more hydrolytically stable than the sol-gel solutions. MOD process challenges include large quantities of carbon to be decomposed during the firing, shrinkage and stress of the thin films, variable chemistry in synthesis of the starting materials (especially when the starting materials for the MOD precursors are metal alkoxides), and long reaction times for the synthesis. For both the sol-gel and MOD precursors, toxic and volatile organic chemical (VOC's) solvents are employed as the vehicle.

This paper will review the chemistry-related issues to production of consistent highquality metal oxide films via the MOD process. The fabrication of thin BaxSr(1-x)TiO3 (BST) films is described. A new class of MOD precursor has been implemented using polyether acids as the organic vehicle. These new materials are both water stable and water soluble. High quality BST thin films made from these precursors are described and capacitors made from these films are compared to the aliphatic acid MOD materials. Improved capacitors using lower resistance electrodes and interconnects are described, as well as devices designed specifically for our specific application.

A comparative study of some tagging methods for the great scallop (Pecten maximus) is reported and intended to increase reliability and reduce costs associated with tagging. Tags were tested for ease of application, legibility, visibility and retention prior to a 17-month study of Pecten maximus in suspended (pearl net) culture. Of the six adhesives tested (standard epoxy resin, rapid epoxy resin, underwater epoxy resin, dental cement, cyanoacrylate fluid and cyanoacrylate gel), rapid epoxy resin and both cyanoacrylates were successful, bonding strongly and quickly to scallop shells. Of the three tag types used, Shellfish Tags (Hallprint) were favoured because they were simpler to apply, more visible, easier to read, and held more data than both Micromarkers (Brady) and engraved codes. In long-term trials 550 scallops were double tagged with Shellfish Tags using cyanoacrylate gel. Loss rates were 16% for tags on the umbo and 0·4% for tags positioned in grooves near to the shell margin. Loss rates did not increase over the 17-month period.

At the beginning of the century, the Constitution was amended to permit direct election of U.S. senators. We examine the shift to determine the extent to which an electoral reform can result in meaningful change. Variables are analyzed that tap the Senate's membership and responsiveness before and after direct election, and House data are employed to control for history effects. The results indicate that changing the mode of senatorial selection did indeed lead to alterations in the composition and sensitivity of the Senate, a finding that should encourage caution regarding the electoral reforms being advocated at the end of the century.

The US House of Representatives underwent a series of reforms in the 1970s which, on paper, changed the institution in fundamental ways. Often, however, institutional inertia is able to transform important ‘paper’ changes into barely discernible actual changes. Have the reforms really led to alterations in the way Congress operates and the policies it produces? To provide a partial answer to this question, we single out one of the reforms – a change in the application of the seniority system in the selection of committee chairmen – and analyse it with an eye towards one hypothesized effect – alterations in the level of party support among key representatives. But by restricting our study in this manner, we are able to provide specific empirical facts which should be of considerable assistance in the important task of formulating more generalized conclusions about the ability of legislative reform to produce real change in the governing process.

It has been ten years since I last spoke to this group; long enough for you to have forgotten what I said at that time. As an expatriate from the profession I am delighted to have this opportunity to meet with you again. I am especially pleased that you have chosen to meet here and on behalf of Dean E. J. Kersting I extend a very sincere welcome and best wishes for a successful program.