258 research outputs found
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A technology acquisition tool for key decision makers
Objectives The purpose of this study was to investigate the need for a technology acquisition tool to be used in the capital purchasing process in health care organizations.
Design Multi-method approach consisting of interviews of ten executives of health care organizations. A written survey was then mailed to Chief Executive Officers at all hospitals in Arizona, Oregon, and Washington.
Measurements Perceptions were assessed utilizing a mail survey on which CEOs self-ranked themselves on a scale that represented the five adopter categories contained in the Diffusion of Innovation theory, along with several questions regarding the perceived attributes of innovations. Several questions then
measured the need for a technology acquisition tool and what items should be included in a technology assessment tool.
Results The response rate was 18%. Descriptive analysis revealed that 93% of responding CEOs felt that the presence of a technology acquisition tool would help key decision makers during the capital acquisition process. CEOs of the respondent hospitals perceived themselves as more readily adapting new technologies or innovations. The perceived attributes of the innovations Compatability, Complexity, Trailability, and Observability were all supported by responses while Relative Advantage was not.
Major Themes The results support the importance of perceived attributes within the Diffusion of Innovation theory. The use of the Diffusion of Innovation theory to design implementation strategies for a capital acquisition tool may increase its chances for success. While CEOs differed on the types of processes they currently used, they all supported the development and use of a technology acquisition tool
Volcanic air pollution and mortality in France 1783–1784
The impact that volcanic eruptions may have upon environments far from the volcanic source is conventionally assumed to depend on climatic modification by emitted gases. However, recent research has suggested that the damage caused by the direct impact of volcanic gases, mainly H2SO4, may be profound. This paper highlights the severity of this mechanism by reference to human sickness and death in France and contiguous with the eruption of the Laki fissure in Iceland in 1783. This work demonstrates the gains which may be made by interdisciplinary teams of researchers and illustrates the valuable knowledge that remains to be revealed by further research in the French historical record
Report of the panel on volcanology, section 4
Two primary goals are identified as focal to NASA's research efforts in volcanology during the 1990s: to understand the eruption of lavas, gases, and aerosols from volcanoes, the dispersal of these materials on the Earth's surface and through the atmosphere, and the effects of these eruptions on the climate and environment; and to understand the physical processes that lead to the initiation of volcanic activity, that influence the styles of volcanic eruptions, and that dictate the morphology and evolution of volcanic landforms. Strategy and data requirements as well as research efforts are discussed
Speleothem U-series constraints on scarp retreat rates and landscape evolution: an example from the Severn valley and Cotswold Hills gull-caves, UK
Modelling landscape evolution requires quantitative estimates of erosional processes. Dating erosional landscape features such as escarpments is usually difficult because of the lack of datable deposits. Some escarpments and valley margins are associated with the formation of mass-movement caves, sometimes known as ‘gull’ or ‘crevice’ caves, which are typically restricted to within 0.5 km of the valley margin or scarp edge. As in other caves, these mass-movement cavities may host speleothems. As gull-caves develop only after valley incision, uranium-series dating of speleothems within them can provide a minimum age for the timing of valley excavation and scarp formation. Here we present data from several gull-caves in the Cotswold Hills, which form the eastern flank of the Severn valley in southern England. U-series ages from these gull-caves yield estimates for both the minimum age of the Cotswold escarpment and the maximum scarp retreat rate. This is combined with data from geological modelling to propose a model for the evolution of the Severn valley and the Cotswold Hills. The data suggest that the location of the escarpment and regional topography is determined not by valley widening and scarp retreat, but by the in situ generation of relief by differential erosion
Volatile Transport by Volcanic Plumes on Earth, Venus and Mars
Explosive volcanic eruptions can produce sustained, buoyant columns of ash and gas in the atmosphere (Fig. 1). Large flood basalt eruptions may also include significant explosive phases that generate eruption columns. Such eruptions can transport volcanic volatiles to great heights in the atmosphere. Volcanic eruption columns can also redistribute chemical species within the atmosphere by entraining ambient atmosphere at low altitudes and releasing those species at much higher altitudes
Adenosine-A3 receptors in neutrophil microdomains promote the formation of bacteria-tethering cytonemes
The A3‐adenosine receptor (A3AR) has recently emerged as a key regulator of neutrophil behaviour. Using a fluorescent A3AR ligand, we show that A3ARs aggregate in highly polarized immunomodulatory microdomains on human neutrophil membranes. In addition to regulating chemotaxis, A3ARs promote the formation of filipodia‐like projections (cytonemes) that can extend up to 100 μm to tether and ‘reel in’ pathogens. Exposure to bacteria or an A3AR agonist stimulates the formation of these projections and bacterial phagocytosis, whereas an A3AR‐selective antagonist inhibits cytoneme formation. Our results shed new light on the behaviour of neutrophils and identify the A3AR as a potential target for modulating their function
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Thickness characteristics of pāhoehoe lavas in the Deccan Province, Western Ghats, India, and in continental flood basalt provinces elsewhere
We provide the first global compilation of pāhoehoe lava-lobe thicknesses from various continental flood basalt provinces (~ 3800 measurements) to compare characteristic thicknesses within and between provinces. We refer to thin lobes (~ ≤ 5m), characteristic of “compound” lavas, as hummocky pāhoehoe lava flows or flow-fields. Conversely, we term thicker lobes, characteristic of “simple” flows, as coming from sheet-lobe-dominated flows. Data from the Deccan Traps and Columbia River flood-basalt provinces are archetypal since they have the most consistent datasets as well as established chemo- and litho-stratigraphies. Examining Deccan lobe thicknesses, we find that previously suggested (and disputed) distinct temporal and regional distributions of hummocky pāhoehoe and sheet-lobe-dominated flow fields are not strongly supported by the data and that each geochemically-defined formation displays both lobe types in varying amounts. Thin flow-lobes do not appear to indicate proximity to source. The modal lobe thickness of Deccan formations with abundant “thin” lava-lobes is 8m, while the mode for sheet-lobe-dominated formations is only 17m. Sheet-lobes up to 75-80m are rare in the Deccan and Columbia River Provinces, and ones > 100m are exceptional globally. For other flood basalt provinces, modal thickness plots show a prevalence towards similar lobe thicknesses to Deccan, with many provinces having some or most lobes in the 5-8m modal range. However, median values are generally thicker, in the 8-12m range, suggesting that sheet-lobes dominate. By contrast, lobes from non-flood basalt flow-fields (e.g., Hawai´i, Snake River Plain) show distinctly thinner modes, sub-5m. Our results provide a quantitative basis to ascertain variations in gross lava morphology and, perhaps, this will in future be related to emplacement dynamics of different flood basalt provinces, or parts thereof. We can also systematically distinguish outlier lobes (or regions) from typical lobes in a province; e.g., North American CAMP lava-lobes are anomalously thick and are closely related to feeder-intrusions, thus enabling a better understanding of conditions required to produce large-volume, thick, flood basalt lava-lobes and flows
Tambora 1815 as a test case for high impact volcanic eruptions: Earth system effects
The eruption of Tambora (Indonesia) in April 1815 had substantial effects on global climate and led to the ‘Year Without a Summer’ of 1816 in Europe and North America. Although a tragic event—tens of thousands of people lost their lives—the eruption also was an ‘experiment of nature’ from which science has learned until today. The aim of this study is to summarize our current understanding of the Tambora eruption and its effects on climate as expressed in early instrumental observations, climate proxies and geological evidence, climate reconstructions, and model simulations. Progress has been made with respect to our understanding of the eruption process and estimated amount of SO2 injected into the atmosphere, although large uncertainties still exist with respect to altitude and hemispheric distribution of Tambora aerosols. With respect to climate effects, the global and Northern Hemispheric cooling are well constrained by proxies whereas there is no strong signal in Southern Hemisphere proxies. Newly recovered early instrumental information for Western Europe and parts of North America, regions with particularly strong climate effects, allow Tambora's effect on the weather systems to be addressed. Climate models respond to prescribed Tambora-like forcing with a strengthening of the wintertime stratospheric polar vortex, global cooling and a slowdown of the water cycle, weakening of the summer monsoon circulations, a strengthening of the Atlantic Meridional Overturning Circulation, and a decrease of atmospheric CO2. Combining observations, climate proxies, and model simulations for the case of Tambora, a better understanding of climate processes has emerged
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