122 research outputs found

    Coupled-channels analysis of the 16^{{\bf 16}}O+208^{{\bf 208}}Pb fusion barrier distribution

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    Analyses using simplified coupled-channels models have been unable to describe the shape of the previously measured fusion barrier distribution for the doubly magic 16^{16}O+208^{208}Pb system. This problem was investigated by re-measuring the fission excitation function for 16^{16}O+208^{208}Pb with improved accuracy and performing more exact coupled-channels calculations, avoiding the constant-coupling and first-order coupling approximations often used in simplified analyses. Couplings to the single- and 2-phonon states of 208^{208}Pb, correctly taking into account the excitation energy and the phonon character of these states, particle transfers, and the effects of varying the diffuseness of the nuclear potential, were all explored. However, in contrast to other recent analyses of precise fusion data, no satisfactory simultaneous description of the shape of the experimental barrier distribution and the fusion cross-sections for 16^{16}O+208^{208}Pb was obtained.Comment: RevTex, 29 pages, 7 postscript figures, to appear in PR

    Transparent Meta-Analysis: Does Aging Spare Prospective Memory with Focal vs. Non-Focal Cues?

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    Background: Prospective memory (ProM) is the ability to become aware of a previously-formed plan at the right time and place. For over twenty years, researchers have been debating whether prospective memory declines with aging or whether it is spared by aging and, most recently, whether aging spares prospective memory with focal vs. non-focal cues. Two recent meta-analyses examining these claims did not include all relevant studies and ignored prevalent ceiling effects, age confounds, and did not distinguish between prospective memory subdomains (e.g., ProM proper, vigilance, habitual ProM) (see Uttl, 2008, PLoS ONE). The present meta-analysis focuses on the following questions: Does prospective memory decline with aging? Does prospective memory with focal vs. non-focal cues decline with aging? Does the size of age-related declines with focal vs. non-focal cues vary across ProM subdomains? And are age-related declines in ProM smaller than agerelated declines in retrospective memory? Methods and Findings: A meta-analysis of event-cued ProM using data visualization and modeling, robust count methods, and conventional meta-analysis techniques revealed that first, the size of age-related declines in ProM with both focal and non-focal cues are large. Second, age-related declines in ProM with focal cues are larger in ProM proper and smaller in vigilance. Third, age-related declines in ProM proper with focal cues are as large as age-related declines in recall measures of retrospective memory

    Transparent Meta-Analysis of Prospective Memory and Aging

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    Prospective memory (ProM) refers to our ability to become aware of a previously formed plan at the right time and place. After two decades of research on prospective memory and aging, narrative reviews and summaries have arrived at widely different conclusions. One view is that prospective memory shows large age declines, larger than age declines on retrospective memory (RetM). Another view is that prospective memory is an exception to age declines and remains invariant across the adult lifespan. The present meta-analysis of over twenty years of research settles this controversy. It shows that prospective memory declines with aging and that the magnitude of age decline varies by prospective memory subdomain (vigilance, prospective memory proper, habitual prospective memory) as well as test setting (laboratory, natural). Moreover, this meta-analysis demonstrates that previous claims of no age declines in prospective memory are artifacts of methodological and conceptual issues afflicting prior research including widespread ceiling effects, low statistical power, age confounds, and failure to distinguish between various subdomains of prospective memory (e.g., vigilance and prospective memory proper)

    Analyzing Stakeholder Water Source Preference Based upon Social Capital: a Case Study of the Fajr Jam Gas Refinery in Iran

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    Gas refineries are among the most water-intensive industries in the world. The Fajr Jam gas refinery is one such example, located in the southern Iran. The indiscriminate use of aquifer resources for this highly profitable industry creates tragedy of the commons effects, causing significant environmental controversy and threatening the long-term water security of the region. It behooves decision makers, therefore, to examine a broad range of adaptive water management strategies for this industry. The implementation of such strategies requires understanding the preferences and potential conflicts that may emerge among competing stakeholder interests. This quantitative social scientific study examines stakeholder preferences among water management options through the lens of social capital. Elite stakeholder representatives (including agricultural organizations, governmental organizations, the Water, and Power Authority, Department of Health, Bureau of Water and Wastewater) were canvassed through a survey instrument using paired comparisons. Data were analyzed using Expert Choice software and an analytic hierarchy process technique. The results show that accountability is the main criterion for selecting the best water sources and ranked first with the Eigenvector 0.62. Also, the results show that the least important criterion was social cohesion with the Eigenvalue 0.033. The criteria of partnership and trust ranked as two and three with Eigenvalues 0.215 and 0.133, respectively. The results indicate that the construction of salt water transmission from the sea (A = 0.240) is the preferred option among other alternatives, and this is confirmed by sensitivity analysis

    Drivers of risk perceptions about the invasive non-native plant Japanese knotweed in domestic gardens

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    This is the final version of the article. Available from Springer Verlag via the DOI in this record.How people perceive risks posed by invasive non-native plants (INNP) can influence attitudes and consequently likely influence behavioural decisions. Although some drivers of risk perception for INNP have been identified, research has not determined those for INNP in domestic gardens. This is concerning as domestic gardens are where people most commonly encounter INNP, and where impacts can be particularly acute. Using a survey approach, this study determined the drivers of perceptions of risk of INNP in domestic gardens and which risks most concern people. Japanese knotweed Fallopia japonica, in Cornwall, UK, where it is a problematic INNP in domestic gardens, was used as a case study. Possible drivers of risk were chosen a priori based on variables previously found to be important for environmental risks. Participants perceived Japanese knotweed to be less frequent on domestic property in Cornwall if their occupation involved the housing market, if they had not had Japanese knotweed in their own garden, if they did not know of Japanese knotweed within 5 km of their home, or if they were educated to degree level. Participants who thought that the consequences of Japanese knotweed being present on domestic property could be more severe had occupations that involved the housing market, knew of Japanese knotweed within 5 km of their home, or were older. Although concern about the damage Japanese knotweed could do to the structure of a property was reported as the second highest motivation to control it by the majority of participants, the perception of threat from this risk was rated as relatively low. The results of this study have implications for policy, risk communication, and garden management decisions. For example, there is a need for policy that provides support and resources for people to manage INNP in their local area. To reduce the impact and spread of INNP we highlight the need for clear and accurate risk communication within discourse about this issue. The drivers identified in this study could be used to target awareness campaigns to limit the development of over- or under-inflated risk perceptions.This project was funded as part of the Wildlife Research Co-Operative between the University of Exeter and the Animal and Plant Health Agency
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