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We have monitored changes in the radial velocities of 24 bright F, G and K dwarf stars (known spectroscopic binaries excluded) for the past six years at CFHT by imposing the absorption lines of HF gas in the spectra to act as wavelength fiducials. The average external error in the δ(velocities) which are based on some 16 stellar lines is 13 m/s corresponds to 0.6 micron in the spectrum or 0.04 of a diode spacing per line. Reductions are complete for 16 stars. There is no evidence for brown dwarf companions in the sample. Two previously unknown spectroscopic binaries were found, and seven stars show indications of significant, long-term, low-level velocity variations which could be interpreted as purturbations by companions of a few Jupiter masses with periods greater than 12 years except for γ Cep, which may have a period of 2.7 years, and ε Eri. Observing time has been guaranteed for at least two more years at CFHT.
The development of small-scale kingdoms in the post-Roman world of northwestern Europe is a key stage in the subsequent emergence of medieval states. Recent excavations at Rhynie in north-eastern Scotland have thrown important light on the emergence of one such kingdom, that of the Picts. Enclosures, sculptured ‘symbol stones’ and long-distance luxury imports identify Rhynie as a place of growing importance during the fifth to sixth centuries AD. Parallels can be drawn with similar processes in southern Scandinavia, where leadership combined roles of ritual and political authority. The excavations at Rhynie and the synthesis of dated Pictish enclosures illustrate the contribution that archaeology can make to the understanding of state formation processes in early medieval Europe.
This Summary for Policymakers presents key findings from the Special Report on Managing the Risks of Extreme Events and Disasters to Advance Climate Change Adaptation (SREX). The SREX approaches the topic by assessing the scientific literature on issues that range from the relationship between climate change and extreme weather and climate events (‘climate extremes’) to the implications of these events for society and sustainable development. The assessment concerns the interaction of climatic, environmental, and human factors that can lead to impacts and disasters, options for managing the risks posed by impacts and disasters, and the important role that non-climatic factors play in determining impacts. Box SPM.1 defines concepts central to the SREX.
The character and severity of impacts from climate extremes depend not only on the extremes themselves but also on exposure and vulnerability. In this report, adverse impacts are considered disasters when they produce widespread damage and cause severe alterations in the normal functioning of communities or societies. Climate extremes, exposure, and vulnerability are influenced by a wide range of factors, including anthropogenic climate change, natural climate variability, and socioeconomic development (Figure SPM.1). Disaster risk management and adaptation to climate change focus on reducing exposure and vulnerability and increasing resilience to the potential adverse impacts of climate extremes, even though risks cannot fully be eliminated (Figure SPM.2). Although mitigation of climate change is not the focus of this report, adaptation and mitigation can complement each other and together can significantly reduce the risks of climate change. [SYR AR4, 5.3]
Case studies contribute more focused analyses which, in the context of human loss and damage, demonstrate the effectiveness of response strategies and prevention measures and identify lessons about success in disaster risk reduction and climate change adaptation. The case studies were chosen to complement and be consistent with the information in the preceding chapters, and to demonstrate aspects of the key messages in the Summary for Policymakers and the Hyogo Framework for Action Priorities.
The case studies were grouped to examine types of extreme events, vulnerable regions, and methodological approaches. For the extreme event examples, the first two case studies pertain to events of extreme temperature with moisture deficiencies in Europe and Australia and their impacts including on health. These are followed by case studies on drought in Syria and dzud, cold-dry conditions in Mongolia. Tropical cyclones in Bangladesh, Myanmar, and Mesoamerica, and then floods in Mozambique are discussed in the context of community actions. The last of the extreme events case studies is about disastrous epidemic disease, using the case of cholera in Zimbabwe, as the example.
The case studies chosen to reflect vulnerable regions demonstrate how a changing climate provides significant concerns for people, societies, and their infrastructure. These are: Mumbai as an example of a coastal megacity; the Republic of the Marshall Islands, as an example of small island developing states with special challenges for adaptation; and Canada's northern regions as an example of cold climate vulnerabilities focusing on infrastructures.
The prevalence of falls and associated injuries increases with age and dependency. The highest occurs among individuals living in long-term care institutions. Preventing falls results in reduced physical and psychological morbidity as well as having cost-saving implications. This review explores both uni- and multifactorial approaches to reducing fall rates and risk in individuals in long-term care, as well as highlighting the differences in this group from community-dwelling individuals.
A new process was developed for deposition of the silicates and oxides of metals such as zirconium and hafnium at low substrate temperatures (100–300°C). The silicon and oxygen source is tris(tert-butoxy)silanol, (tBuO)3SiOH, and the metal precursors are metal amides. A typical reaction is
in which the ligand L is ethylmethylamide, -NEtMe. The precursor vapors were alternately pulsed into a heated reactor, yielding about 0.3 to 0.7 nm of metal silicate film for each cycle. Replacing the silanol pulses with water pulses yields pure metal oxides with a thickness of about 0.1 to 0.15 nm per cycle. The silicon content of the films can be adjusted to any desired value by replacing some of the silanol pulses by water pulses. This new process has a number of advantages over previous methods for depositing metal silicates. Uniformity of thickness and stoichiometry are readily achieved. The deposition atmosphere is non-oxidizing, so that formation of low-k interfacial oxides between the deposited layer and a silicon substrate is minimized. The new halogen-free precursors avoid halogen contamination of films and corrosion of deposition systems. This process is a promising method for forming the next generation of ultra-thin high-k gate dielectrics in silicon-based microelectronics.
The aqueous deposition of calcium oxalate onto colloidal oxides has been
studied as a model system for understanding heterogeneous nucleation
processes of importance in biomimetic synthesis of ceramic thin films.
Calcium oxalate nucleation has been monitored by measuring induction times
for nucleation using Constant Composition techniques and by measuring
nucleation densities on extended oxide surfaces using an atomic force
microscope. Results show that the dependence of calcium oxalate nucleation
on solution supersaturation fits the functional form predicted by classical
nucleation theories. Anionic surfaces appear to promote nucleation better
than cationic surfaces, lowering the effective energy barrier to
Although significant advances have been made to provide mechanically strong and nontoxic metals and alloys, biological integration of devices into natural tissues remains a problem. The Surface Induced Mineralization (SIM) and Void Metal Composite (VMC) processes produce a bioactive porous metal implant coating/device which may address many of the problems associated with conventional processing methods.
The VMC process produces materials which have cylindrical pores of uniform diameter which can completely penetrate the structure of the material. The pore diameter, orientation and interconnectivety are easily controlled
The SIM process uses the idea of nature's template-mediated mineralization by chemically modifying the implant to produce a surface which induces heterogeneous nucleation from aqueous solution. SIM produced bioactive coatings provide 1) control of the thickness and density of the mineral phase, 2) a way to coat porous metals, complex shapes and large objects, 3) the ability to coat a wide variety of materials, 4) potential choice for the phase of the mineral formed.