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This article presents the background to and prospects for a new initiative in archaeological field survey and database integration. The Roman Hinterland Project combines data from the Tiber Valley Project, Roman Suburbium Project, and the Pontine Region Project into a single database, which the authors believe to be one of the most complete repositories of data for the hinterland of a major ancient metropolis, covering nearly 2000 years of history. The logic of combining these databases in the context of studying the Roman landscape is explained and illustrated with analyses that show their capacity to contribute to major debates in Roman economy, demography, and the longue durée of the human condition in a globalizing world.
The Dark Energy Survey is undertaking an observational programme imaging 1/4 of the southern hemisphere sky with unprecedented photometric accuracy. In the process of observing millions of faint stars and galaxies to constrain the parameters of the dark energy equation of state, the Dark Energy Survey will obtain pre-discovery images of the regions surrounding an estimated 100 gamma-ray bursts over 5 yr. Once gamma-ray bursts are detected by, e.g., the Swift satellite, the DES data will be extremely useful for follow-up observations by the transient astronomy community. We describe a recently-commissioned suite of software that listens continuously for automated notices of gamma-ray burst activity, collates information from archival DES data, and disseminates relevant data products back to the community in near-real-time. Of particular importance are the opportunities that non-public DES data provide for relative photometry of the optical counterparts of gamma-ray bursts, as well as for identifying key characteristics (e.g., photometric redshifts) of potential gamma-ray burst host galaxies. We provide the functional details of the DESAlert software, and its data products, and we show sample results from the application of DESAlert to numerous previously detected gamma-ray bursts, including the possible identification of several heretofore unknown gamma-ray burst hosts.
Cholinergic receptors (muscarinic subtypes M1 and M2, and putative nicotinic binding) have been examined in the hippocampus obtained at autopsy from a variety of patients with cognitive disorders (Alzheimer's, Parkinson's, and Huntington's diseases, Down's Syndrome and alcoholic dementia) and compared with neurologically normal controls and cases of Motor Neuron disease. In all of the disorders associated with a pre-synaptic cortical cholinergic deficit reflected by an extensive loss of choline acetyltransferase (Alzheimer's disease, Parkinson's disease and Down's Syndrome) there was a substantial reduction in the binding of (3H) nicotine to the nicotinic receptor. By contrast reductions in both muscarinic subtypes (M1 and M2) were apparent to only a moderate extent in Alzheimer's disease, whereas in Parkinson's disease binding was significantly increased (apparently not in relation to anti-cholinergic drug treatment) in the non-demented but not demented cases. A further abnormality detected in Alzheimer's disease but not the other disorders investigated was a decrease in an endogenous inhibitor of nicotinic binding, the identity of which is as yet unknown but which may be a candidate for a possible endogenous modulator of the nicotinic receptor. These observations suggest that in Alzheimer's disease not only muscarinic but also nicotinic receptor function should be considered in relation both to future therapeutic strategies and, in the search for a clinical marker which might be of diagnostic value, to potential probes of the cortical cholinergic system.
A project to develop an Accounting Standard for Insurance, with the aim of enhancing understandability, relevance, reliability and comparability of general purpose financial reporting for insurance worldwide, is being progressed by the International Accounting Standards Board. The basis of the proposals is that assets and liabilities be shown at fair values (market values for quoted instruments). This paper, prepared by a Working Party established by the Life Board of the United Kingdom actuarial profession, summarises and comments upon a number of the principal features of the proposals, as they have emerged up to September 2001. The paper goes on to consider how a system of reporting for prudential regulatory purposes might be built upon a fair value general reporting base, summarising the thinking of a number of other bodies, proposing certain principles and suggesting lines of development. The appendices to the paper discuss a number of issues in further depth and present some illustrative results of some investigations into applying fair value methods in practice. The emphasis of the paper is on reporting for life assurance business, although many of the principles apply equally to general insurance.
Increasingly, modern business and investment management techniques are founded on approaches to measurement of profit and risk developed by financial economists. This paper begins by analysing corporate pension provision from the perspective of such financial theory. The results of this analysis are then reconciled with the sometimes contradictory messages from traditional actuarial valuation approaches and the alternative market-based valuation paradigm is introduced. The paper then proposes a successful blueprint for this mark-to-market valuation discipline and considers whether and how it can be applied to pension schemes both in theory and in practice. It is asserted that adoption of this market based approach appears now to be essential in many of the most critical areas of actuarial advice in the field of defined benefit corporate pension provision and that the principles can in addition be used to establish more efficient and transparent methodologies in areas which have traditionally relied on subjective or arbitrary methods. We extend the hope that the insights gained from financial theory can be used to level the playing field between defined benefit and defined contribution arrangements from both corporate and member perspectives.
Globally, introductions of non-indigenous species have caused dramatic economic and ecological damage. Most research on marine invasions has occurred in locations easily accessible by researchers, but much less is known about introductions to remote islands. In the central Pacific, Palmyra Atoll represents one of the last remaining quasi-pristine reef systems left in the world. In the 1940s the Atoll underwent extensive military modifications, potentially making it susceptible to invasive species. Here we describe the presence of five non-indigenous invertebrate and algal introductions at Palmyra, including two sponges, Haliclona (Sigmadocia) caerulea and Gelliodes fibrosa; one bryozoan; Zoobotryon verticillatum; one hydroid, Pennaria disticha and one macroalga, Acanthophora spicifera. The Hawaiian Archipelago is the most likely source of the introductions via shipping or yachting activity to the Atoll. Currently, the impacts of these introductions remain unknown although future monitoring will assess the influence of these non-indigenous species on this remote reef system.
Over the past 3 years, we have conducted a survey of 100 square degrees of the southern Galactic plane with the Mopra radiotelescope (HOPS). The survey includes observations of multiple spectral lines in the 12 mm band, with the most important being the water maser transition at 22.2 GHz and the non-metastable inversion transitions of ammonia. We report on initial results from HOPS, including the detection of 540 water masers, about two-thirds of which appear to be new detections. We also find widespread emission in the NH3 (1,1) line, as well as detec tions in the NH3 (2,2), (3,3), (6,6) and (9,9) lines.
Seahorses and their syngnathid relatives have provided a focus for efforts to ensure sustainable use of marine resources, with new international trade controls (CITES Appendix II) implemented in May 2004. We demonstrate how a study of international trade can be used to assess relative levels of threat and set domestic research and conservation priorities. Australia has remarkably high syngnathid biodiversity with at least 14 seahorse species, two endemic sea dragon species, and 90 species of pipefishes and pipehorses found in its territorial waters. Our objectives were to quantify species, trade routes, volumes, values and temporal trends in syngnathid trade to and from Australia. We found that Australia is probably the major global supplier of dried pipehorses Solegnathus spp.. These fishes, including at least one endemic species, are sourced from trawl bycatch and comprise Australia's largest syngnathid export, by both volume and value. Research is urgently needed to evaluate the impacts and sustainability of trawling on pipehorse populations. Australia is also the sole supplier of two sea dragon species, Phycodurus eques and Phyllopteryx taeniolatus, for the live aquarium trade. Although lucrative, the number of wild-caught individuals involved in this trade was relatively low and probably of low conservation risk relative to habitat loss. Exports of seahorses and other pipefish species, and imports of all syngnathid species, are minor on a global scale, although the burgeoning aquaculture industry for seahorses requires careful evaluation for its potential impacts on wild populations.
This article reports the first Richtmyer–Meshkov instability experiments using an improved version of the Atomic Weapons Establishment convergent shock tube. These investigate the shock-induced turbulent mixing across the interfaces of an air/dense gas/air region. Multipoint ignition of a detonatable gas mixture produces a cylindrically convergent shock that travels into a test cell containing the dense gas region. The mixing process is imaged with shadowgraphy. Sample results are presented from an unperturbed experiment and one with a notch perturbation imposed on one of the dense gas interfaces. The unperturbed experiment shows the mixing across the dense gas boundaries and the motion of the bulk dense gas region. Imposition of the notch perturbation produces a mushroom-shaped air void penetrating the dense gas region. Three-dimensional simulations performed using the AWE TURMOIL3D code are presented and compared with the sample experimental results. A very good agreement is demonstrated. Conducting these first turbulent mixing experiments has highlighted a number of areas for future development of the convergent shock-tube facility; these are also presented.
The formation of ultra-shallow junctions (USJs) for future integrated circuit technologies requires preamorphization and high dose boron doping to achieve high activation levels and abrupt profiles. To achieve the challenging targets set out in the semiconductor roadmap, it is crucial to reach a much better understanding of the basic physical processes taking place during USJ processing. In this paper we review current understanding of dopant-defect interactions during thermal processing of device structures – interactions which are at the heart of the dopant diffusion and activation anomalies seen in USJs. First, we recall the formation and thermal evolution of End of Range (EOR) defects upon annealing of preamorphized implants (PAI). It is shown that various types of extended defect can be formed: clusters, {113} defects and dislocation loops. During annealing, these defects exchange Si interstitial atoms and evolve following an Ostwald ripening mechanism. We review progress in developing models based on these concepts, which can accurately predict EOR defect evolution and interstitial transport between the defect layer and the surface. Based on this physically based defect modelling approach, combined with fully coupled multi-stream modelling of dopant diffusion, one can perform highly predictive simulations of boron diffusion and de/re-activation in Ge-PAI boron USJs. Agreement between simulations and experimental data is found over a wide range of experimental conditions, clearly indicating that the driving mechanism that degrades boron junction depth and activation is the dissolution of the interstitial defect band. Finally, we briefly outline some promising methods, such as co-implants and/or vacancy engineering, for further down-scaling of source-drain resistance and junction depth.
Towed underwater TV observations at 440 m in the northern Evoikos Gulf, Greece, revealed a soft mud plain heavily bioturbated by the thalassinidean Calocaris macandreae, with Callianassa subterranea and Nephrops norvegicus also present. Ejecta mounds and feeding traces indicated the presence of a large echiuran, provisionally identified as Maxmuelleria gigas. The locality also supported a dense population of a second echiuran, Bonellia viridis, a species not previously recorded as an inhabitant of sedimentary environments.
Reactive transport simulations are being used to evaluate the nature and extent of radionuclide contamination within alluvium surrounding an underground nuclear test at the Nevada Test Site (NTS). Simulations are focused on determining the abundance and chemical nature of radionuclides that are introduced into groundwater, as well as the rate and extent of radionuclide migration and reaction in groundwater surrounding the working point of the test. Transport simulations based upon a streamline-based numerical model are used to illustrate the nature of radionuclide elution out of the near-field environment and illustrate the conceptual modeling process. The numerical approach allowed for relatively complex flow and chemical reactions to be considered in a computationally efficient manner. The results are particularly sensitive to the rate of melt glass dissolution, distribution of reactive minerals in the alluvium, and overall groundwater flow configuration. They provide a rational basis from which defensible migration assessments can proceed.
We studied the equilibrium architecture of polymer layers strongly adsorbed from the melt. Immobilized layers of poly-(methyl methacrylate) (PMMA) were produced by the following method: 1) The polymer was spin-coated onto silanol bearing surfaces of single crystal and fused quartz, and annealed at melt conditions, 2) The annealed layer was quenched to room temperature (below the glass transition temperature) in order to “freeze in” the melt structure near the substrate, 3) Unbound material was leached away in good solvent (benzene) to leave a residual, strongly-adsorbed layer. The architecture of this layer was studied by neutron reflection. Data on dried adsorbed layers indicates a dense PMMA film whose thickness gradually increases with annealing time in the melt from a minimal value. Evidently, annealing gradually relaxes a rather flat non-equilibrium structure produced by spin-coating. The thicknesses, h, in a series of dry layers annealed long enough to achieve equilibrium conditions in the melt scale as h ∼ N1/2. Data on swollen layers suggest a dilute, extended layer, but the preliminary results cannot give a definitive confirmation of the brush structure predicted by Guiselin.11
The electrical properties of sol-gel prepared aluminosilicate films were investigated for suitability in electronic applications. The aluminosilicate films exhibited apparent closed porosity and a dielectric constant as low as ≍5 with processing temperatures from 373 K to 873 K. The porosity was inaccessible to nitrogen at 77 K, helium at 293 K, and water vapor at 293 K. Both bulk and thin-film samples were analyzed for hydroxyl and carbon contents to elucidate the relative dependence of the measured electrical properties on processing conditions. Experiments indicate it is possible to vary the porosity in bulk material in ways that should improve electrical properties.
Perovskite is the least durable of the resistate minerals comprising Synroc-C and it is desirable to reduce its abundance in Synroc. Kinetic limitations and competition with Csapparently affect the incorporation of Sr into hollandite during hot-pressing at 1200ºC/20 MPa so that ∼ 10% of perovskite (a value below the percolation limit) is probably an optimum target. Zirconolite-rich Synroc formulations have been prepared for actinide-rich wastes. Background XRD and TEM studies have also been performed to study the crystal-chemical behaviour of Nd (a simulant of trivalent actinides) in zirconolite. Either rare-earth compensated perovskite or freudenbergite in Synroc can evidently be used to immobilise Na-bearing HLW.
Models of the transport of sorbing radioelements through geological materials have been developed. These models couple a surface-complexation model of sorption processes with transport simulations in the CHEQMATE code. The chemical model has been shown to reproduce trends observed in batch sorption experiments. This approach may ultimately be used to investigate possible limitations to the use of models using simple Kds in repository safety-assessments. The main aim of the study reported in this paper is to increase confidence in the use of the coupled models. Simulations of through-diffusion experiments of uranium with London clay and plutonium with sandstone are presented. In both cases gluconate is present, as a simulant of organic degradation products of cellulose likely to be present in a low- or intermediate-level waste repository.
In the alumina-silica system, the surface area of gels exhibit dependence upon both composition and the fluid in the pores during drying. Under controlled conditions, an anomalous drop in both the surface area and skeletal density of identically prepared gels occurs at a composition of 47% alumina. An effort has been made to understand the reasons for this phenomenon. The effect of various solution precursor systems has been investigated. Precursors that contain boehmite, or other colloidal species, do not exhibit low surface area/density at 47% alumina. Data from light scattering, infrared spectroscopy, and solution NMR will be discussed for the precursor system used to prepare low surface area gels. Data will be interpreted to determine the effect of solution structure on gel characteristics.