Quantification of channel planform change on the lower Rangitikei River, New Zealand, 1949-2007: response to management?

The Rangitikei River, a large gravel‐bed wandering river located in the North Island of New Zealand, has outstanding scenic characteristics, recreational, fisheries and wildlife habitat features. Recently concerns have been raised over the potential negative impact that perceived channel changes in the latter part of the 20th century may be having on the Rangitikei River recreational fishery. This study describes and quantifies the large‐scale morphological changes that have occurred in selected reaches of the lower Rangitikei River between 1949 and 2007. This research utilised historical aerial photography and analysis in ArcGIS® to quantify channel planform change in three reaches, encompassing ~18 km of the lower Rangitikei River. This showed that the lower Rangitikei was transformed from a multi‐channelled planform to a predominantly single‐thread wandering planform, with an associated reduction in morphological complexity and active channel width of up to 74%, between 1949 and 2007. Bank protection measures instigated under the Rangitikei River Scheme have primarily driven these changes. Gravel extraction has also contributed by enhancing channel‐floodplain disconnection and exacerbating sediment deficits. The findings of this study have implications for future management of the Rangitikei. Previous lower Rangitikei River management schemes have taken a reach‐based engineering approach with a focus on bank erosion protection and flood mitigation. This study has confirmed the lower river has responded geomorphologically to these goals of river control. However questions as to the economic and ecological sustainability of this management style may encourage river managers to consider the benefits of promoting a self‐adjusting fluvial system within a catchment‐framed management approach

Testing based on the RELAY model of error detection

RELAY, a model for error detection, defines revealing conditions that guarantee that a fault originates an error during execution and that the error transfers through computations and data flow until it is revealed. This model of error detection provides a fault-based criterion for test data selection. The model is applied by choosing a fault classification, instantiating the conditions for the classes of faults, and applying them to the program being tested. Such an application guarantees the detection of errors caused by any fault of the chosen classes. As a formal mode of error detection, RELAY provides the basis for an automated testing tool. This paper presents the concepts behind RELAY, describes why it is better than other fault-based testing criteria, and discusses how RELAY could be used as the foundation for a testing system

An analysis of test data selection criteria using the RELAY model of fault detection

RELAY is a model of faults and failures that defines failure conditions, which describe test data for which execution will guarantee that a fault originates erroneous behavior that also transfers through computations and information flow until a failure is revealed. This model of fault detection provides a framework within which other testing criteria's capabilities can be evaluated. In this paper, we analyze three test data selection criteria that attempt to detect faults in six fault classes. This analysis shows that none of these criteria is capable of guaranteeing detection for these fault classes and points out two major weaknesses of these criteria. The first weakness is that the criteria do not consider the potential unsatisfiability of their rules; each criterion includes rules that are sufficient to cause potential failures for some fault classes, yet when such rules are unsatisfiable, many faults may remain undetected. Their second weakness is failure to integrate their proposed rules; although a criterion may cause a subexpression to take on an erroneous value, there is no effort made to guarantee that the intermediate values cause observable, erroneous behavior. This paper shows how the RELAY model overcomes these weaknesses

The Focal Account: Indirect Lie Detection Need Not Access Unconscious, Implicit Knowledge

People are poor lie detectors, but accuracy can be improved by making the judgment indirectly. In a typical demonstration, participants are not told that the experiment is about deception at all. Instead, they judge whether the speaker appears, say, tense or not. Surprisingly, these indirect judgments better reflect the speaker’s veracity. A common explanation is that participants have an implicit awareness of deceptive behavior, even when they cannot explicitly identify it. We propose an alternative explanation. Attending to a range of behaviors, as explicit raters do, can lead to conflict: A speaker may be thinking hard (indicating deception) but not tense (indicating honesty). In 2 experiments, we show that the judgment (and in turn the correct classification rate) is the result of attending to a single behavior, as indirect raters are instructed to do. Indirect lie detection does not access implicit knowledge, but simply focuses the perceiver on more useful cues

I. Collisional evolution and reddening of asteroid surfaces: The problem of conflicting timescales and the role of size-dependent effects

Space weathering is the generic term used for processes that modify the optical properties of surfaces of atmosphereless rocky bodies under exposure to the space environment. The general agreement about the relevance of the effects of space weathering on the spectral properties of S-complex asteroids fails when some basic quantitative estimates are attempted. In particular, there is severe disagreement regarding the typical timescales for significant spectral reddening to occur, ranging from 1 Myr to 1 Gyr. Generally speaking, the spectral reddening of an individual object can be considered as the sum of three terms, one (which is relevant for statistical analyses) depending on the exposure of the object to space weathering during its lifetime, a second one due to the original surface composition, and a third one (a "noise" term) due to the combination of poorly constrained effects (e.g., structure and texture of the surface). The surface of an asteroid is usually covered by regolith, and its presence and properties presumably play a critical role in the weathering processes. In this paper we discuss the role played by collisional evolution in affecting the spectral properties of asteroids and refreshing the surfaces due to the formation of ejecta, and the necessity of a simultaneous modeling of collisions and weathering processes. We introduce a new idea, based on the possibility of a sort of saturation of the refreshing process whenever a massive reaccumulation of the impact ejecta takes place. In this case, a dependence of the overall reddening on the asteroid size should naturally come out. We show that this conclusion is indeed supported by available main belt asteroid spectroscopic data.Comment: Accepted by MNRA