6 research outputs found
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A system approach to nuclear facility monitoring
Sensor technology for use in nuclear facility monitoring has reached and advanced stage of development. Research on where to place these sensors in a facility and how to combine their outputs in a meaningful fashion does not appear to be keeping pace. In this paper, we take a global view of the problem where sensor technology is viewed as only one piece of a large puzzle. Other pieces of this puzzle include the optimal location and type of sensors used in a specific facility, the rate at which sensors record information, and the risk associated with the materials/processes at a facility. If the data are analyzed off-site, how will they be transmitted? Is real-time analysis necessary? Are we monitoring only the facility itself, or might we also monitor the processing that occurs there? How are we going to combine the output from the various sensors to give us an accurate picture of the state of the facility? This paper will not try to answer all these questions, but rather it will attempt to stimulate thought in this area by formulating a systems approach to the problem demonstrated by a prototype system and a systems proposed for an actual facility. Our focus will be on the data analysis aspect of the problem
Herbivory: effects on plant abundance, distribution and population growth
Plants are attacked by many different consumers. A critical question is how often, and under what conditions, common reductions in growth, fecundity or even survival that occur due to herbivory translate to meaningful impacts on abundance, distribution or dynamics of plant populations. Here, we review population-level studies of the effects of consumers on plant dynamics and evaluate: (i) whether particular consumers have predictably more or less influence on plant abundance, (ii) whether particular plant life-history types are predictably more vulnerable to herbivory at the population level, (iii) whether the strength of plant–consumer interactions shifts predictably across environmental gradients and (iv) the role of consumers in influencing plant distributional limits. Existing studies demonstrate numerous examples of consumers limiting local plant abundance and distribution. We found larger effects of consumers on grassland than woodland forbs, stronger effects of herbivory in areas with high versus low disturbance, but no systematic or unambiguous differences in the impact of consumers based on plant life-history or herbivore feeding mode. However, our ability to evaluate these and other patterns is limited by the small (but growing) number of studies in this area. As an impetus for further study, we review strengths and challenges of population-level studies, such as interpreting net impacts of consumers in the presence of density dependence and seed bank dynamics