Uncertainty Matters: Computer Models at the Science–Policy Interface

The use of computer models offers a general and flexible framework that can help to deal with some of the complexities and difficulties associated with the development of water management plans as prescribed by the Water Framework Directive. However, despite the advantages modelling presents, the integration of information derived from models into policy is far away from being trivial or the norm. Part of the difficulties of this integration is rooted in the lack of confidence policy makers have on the incorporation of modelling information into policy formulation. In this paper we examine the reasons for this apparent lack of confidence and explore how some tools, presently in use, address this problem. We conclude that public confidence in models is highly dependent on the way uncertainties are addressed and suggest possible directions of action to improve the current situation. Four real case studies illustrate how computer models have been used in The Netherlands for carrying out management plans at regional and national scale. We suggest that the solution to integrate modelling information into policy formulation lies on both the modelling and the policy-making communities.     

Operations and management of a campus packet network

The operation and management of the Kansas University Packet Switch Network (KUPSN),which provides interactive and file transfer services to its users, is discussed, focussing on the problems encountered and solutions developed. Areas of network management of particular concern are identified, and tools developed to deal with them are described. Management system integration and the evolution of problem-handling procedures are discussed     

Heterogeneity effects in visual search predicted from the group scanning model.

The group scanning model of feature integration theory suggests that Ss search visual displays serially by groups, but process items within each group in parallel. Group size is determined by the discriminability of the targets in the background of distractors. When the target is poorly discriminable, the size of the scanned group will be small, and search will be slow. The model predicts that group size will be smallest when targets of an intermediate value on a perceptual dimension are presented in a heterogeneous background of distractors that have higher and lower values on the same dimension. Experiment 1 (30 Ss) demonstrates this effect; Exp 2 (12 Ss) controls for a possible confound of decision complexity in Exp 1. For simple feature targets, the group scanning model provides a good account of the visual search process. (French abstract) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Frontal brain activation in repressors and nonrepressors.

Assessed whether resting anterior asymmetry would discriminate individual differences in repressive-defensive coping styles. In 2 sessions, resting electroencephalogram was recorded from female adults during 8 60-sec baselines. Ss were classified as repressors or nonrepressors on the basis of scores on the Marlowe-Crowne Social Desirability Scale (MC), the State-Trait Anxiety Inventory (STAI), and the Beck Depression Inventory (BDI). In midfrontal and lateral frontal sites, repressors demonstrated relative left hemisphere activation when compared with other groups. The MC, but not the STAI or the BDI, contributed unique variance to frontal asymmetry. Relative left frontal activation may be linked to a self-enhancing regulatory style that promotes lowered risk for psychopathology. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

The vulnerability of geometric sequences based on fields of odd characteristic

A new method of cryptologic attack on binary sequences is given, using their linear complexities relative to odd prime numbers. We show that, relative to a particular prime number p, the linear complexity of a binary geometric sequence is low. It is also shown that the prime p can be determined with high probability by a randomized algorithm if a number of bits much smaller than the linear complexity is known. This determination is made by exploiting the imbalance in the number of zeros and ones in the sequences in question, and uses a new statistical measure, the partial imbalance.This project was sponsored by the National Security Agency under Grant No. MDA904-91-H-0012. The United States Government is authorized to reproduce and distribute reprints notwithstanding any copyright notation hereon.     

Regulation of free choline in rat brain: dietary and pharmacological manipulations

The present study analyses, comparatively, the kinetics of free choline in the brain of rats during dietary and pharmacological manipulations. Low-choline diet halved the choline plasma level but did not cause significant changes of CSF choline. High-choline diet, hypoxia and treatment with nicotinamide increased brain choline availability through a central site of action and increased the CSF choline concentration. CSF choline concentrations were more effectively elevated by nicotinamide treatment (20-25 microM) than by acute choline administration (13-15 microM). Increases of CSF choline, due to brain choline mobilization, were consistently associated with a net release of choline from the brain as reflected by strongly negative arterio-venous differences (AVD) of brain choline. The balance between release and uptake of brain choline was controlled by the arterial plasma choline level in all treatment groups; however, the normal 'reversal point' of 15 microM--representing the plasma choline level where uptake and release of brain choline are balanced--was shifted to more than 40 microM by high-choline diet and nicotinamide. In conclusion, our data characterize the release of choline into the venous blood as an important component of brain choline homeostasis. Furthermore, we demonstrate that the concentration of brain choline (e.g. as a precursor of acetylcholine) can be enhanced more efficiently by manipulating choline homeostatic mechanisms than by acute choline administration.     

Self-efficacy expectations predict survival for patients with chronic obstructive pulmonary disease.

Evaluated the validity of self-efficacy expectations as predictors of mortality for 119 patients with chronic obstructive pulmonary disease. Ss completed 4 physiological measures that represent common clinical indicators of disease severity: forced expiratory volume in 1 s(FEV1.0), arterial blood gas measurement of resting partial pressure of oxygen (PaO?), single-breath diffusing capacity (DLCO), and maximum oxygen uptake (V02max) during exercise. In addition, self-reported self-efficacy expectation for walking on a treadmill was measured. Self-efficacy was a significant univariate predictor of 5-yr survival. However, when controlling for FEV1.0 in multivariate survival analysis, self-efficacy had only a marginal effect. Simple self-report scales may provide significant information about health status. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Microwave cavity perturbation technique: Part I: Principles

This report reviews the analysis used to extract the complex conductivity of a compound from a microwave cavity perturbation measurement. We intend to present a generalized treatment valid for any spheroidally shaped sample of arbitrary conductivity which is placed at either the electric or magnetic field antinode of the cavity. To begin with, we establish the relationship between the measured parameters and the conductivity for a spherical sample. Next, we extend these results to the case of spheroids; and for the first time, we cover all different configurations that one can possibly use to study an arbitrary conducting sample inside a cavity: in particular, all possible orientations of the sample with respect to the applied field are solved.     

Eyewitness persuasion: How and how well do fact finders judge the accuracy of adults' and children's memory reports?

Children (aged 5–6 and 9–10 yrs) and adults participated in an eventful laboratory session and provided memory reports of the session. In 3 experiments, college students and parents viewed videotapes of highly accurate and highly inaccurate reports. In 2 experiments, these "fact finders" rated adult witnesses more believable and accurate than younger child witnesses, even when both groups were equally accurate. Perceptions of confidence and consistency mediated credibility judgments. Accurate witnesses were judged more believable and accurate than inaccurate witnesses. Higher perceived confidence, longer free recall, and fewer memory failure admissions were associated with more accurate adult memory reports. Fact finders overused confidence and underused the other cues in achieving modest accuracy discernment. The results suggest how strong and weak memory reports differ and how fact finders may learn to differentiate them. (PsycINFO Database Record (c) 2010 APA, all rights reserved)