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Feedback Experiments (feedback + experiment)
Selected AbstractsValuation Bias in Commercial Appraisal: A Transaction Price Feedback ExperimentREAL ESTATE ECONOMICS, Issue 4 2001J. Andrew Hansz Experiments were conducted to test the hypothesis that transaction price feedback may bias valuation judgment. Among participating appraisers, evidence of asymmetrical response was found. The group receiving transaction feedback indicating that current judgments were "too low" responded with judgments in subsequent, unrelated valuations that were significantly higher than the group that received no feedback. The response from "too high" feedback was in the expected direction (lower value judgments) but was not significant. Additionally, valuation dispersion of around 10% revealed in these experiments is consistent with studies of valuation variability and may reflect an upper bound of typical commercial appraisal dispersion. [source] An Analysis of Two Liquid-State Adaptive Feedback ExperimentsISRAEL JOURNAL OF CHEMISTRY, Issue 1 2007Paul Brumer Adaptive feedback experiments, which provide an engineering oriented approach to optimizing a desired target in a molecular process, have been extensively developed over the past decade. Efforts to extract the control mechanisms that underlie the observed control have, however, only recently begun in earnest. We describe the results of the analyses of two liquid state adaptive feedback experiments, showing that the resultant control takes little advantage of coherent quantum effects. [source] Plant species and functional group effects on abiotic and microbial soil properties and plant,soil feedback responses in two grasslandsJOURNAL OF ECOLOGY, Issue 5 2006T. MARTIJN BEZEMER Summary 1Plant species differ in their capacity to influence soil organic matter, soil nutrient availability and the composition of soil microbial communities. Their influences on soil properties result in net positive or negative feedback effects, which influence plant performance and plant community composition. 2For two grassland systems, one on a sandy soil in the Netherlands and one on a chalk soil in the United Kingdom, we investigated how individual plant species grown in monocultures changed abiotic and biotic soil conditions. Then, we determined feedback effects of these soils to plants of the same or different species. Feedback effects were analysed at the level of plant species and plant taxonomic groups (grasses vs. forbs). 3In the sandy soils, plant species differed in their effects on soil chemical properties, in particular potassium levels, but PLFA (phospholipid fatty acid) signatures of the soil microbial community did not differ between plant species. The effects of soil chemical properties were even greater when grasses and forbs were compared, especially because potassium levels were lower in grass monocultures. 4In the chalk soil, there were no effects of plant species on soil chemical properties, but PLFA profiles differed significantly between soils from different monocultures. PLFA profiles differed between species, rather than between grasses and forbs. 5In the feedback experiment, all plant species in sandy soils grew less vigorously in soils conditioned by grasses than in soils conditioned by forbs. These effects correlated significantly with soil chemical properties. None of the seven plant species showed significant differences between performance in soil conditioned by the same vs. other plant species. 6In the chalk soil, Sanguisorba minor and in particular Briza media performed best in soil collected from conspecifics, while Bromus erectus performed best in soil from heterospecifics. There was no distinctive pattern between soils collected from forb and grass monocultures, and plant performance could not be related to soil chemical properties or PLFA signatures. 7Our study shows that mechanisms of plant,soil feedback can depend on plant species, plant taxonomic (or functional) groups and site-specific differences in abiotic and biotic soil properties. Understanding how plant species can influence their rhizosphere, and how other plant species respond to these changes, will greatly enhance our understanding of the functioning and stability of ecosystems. [source] An Analysis of Two Liquid-State Adaptive Feedback ExperimentsISRAEL JOURNAL OF CHEMISTRY, Issue 1 2007Paul Brumer Adaptive feedback experiments, which provide an engineering oriented approach to optimizing a desired target in a molecular process, have been extensively developed over the past decade. Efforts to extract the control mechanisms that underlie the observed control have, however, only recently begun in earnest. We describe the results of the analyses of two liquid state adaptive feedback experiments, showing that the resultant control takes little advantage of coherent quantum effects. [source] Analytical Expressions for Quantitative Scanning Electrochemical Microscopy (SECM)CHEMPHYSCHEM, Issue 3 2010Christine Lefrou Dr. Abstract Scanning electrochemical microscopy (SECM), is a recent analytical technique in electrochemistry, which was developed in the 1990s and uses microelectrodes to probe various surfaces. Even with the well-known disc microelectrodes, the system geometry is not as simple as in regular electrochemistry. As a consequence even the simplest experiments, the so-called positive and negative feedback approach curves, cannot be described with exact analytical expressions. This review gathers all the analytical expressions available in the SECM literature in steady-state feedback experiments. Some of them are claimed as general expressions, other are presented as approximate. Their validity is discussed in the light of the current understanding and computer facilities. [source] | ||||||||||