Impacts of the North Atlantic Oscillation on Scandinavian Hydropower Production and Energy Markets

Dramatic swings in the North Atlantic oscillation (NAO) during the 1990s motivated the authors to build a statistical model of NAO impacts on hydropower production and energy markets in Scandinavia. Variation in the NAO index is shown to explain 55% of the variance of streamflow in Norway and up to 30% of the variance in Norway's hydropower output. It is also possible to identify the influence of NAO anomalies on electricity consumption and prices. Government liberalization allowed a financial market to grow around the international trading of electricity, which in Norway is produced almost entirely from hydropower. The model offers a possible tool for predicting the effects of future NAO movements on hydropower production and energy prices in Scandinavia. The potential influence of skillful climate prediction is discussed.     

A discrete-scatterer model for ultrasonic images of rough surfaces

Automated analysis of ultrasonic images could be greatly improved with model-based Bayesian methods for image analysis. Such an approach would require an accurate probabilistic image model representing ultrasonic images in terms of the gross shape of underlying anatomical structure. Existing probabilistic models for ultrasonic image data do not adequately incorporate structure shape or system characteristics; thus, a substantially new approach is warranted. Toward that goal, we have developed models for the imaging system and rough surface with the following objectives: (1) accuracy in representation of basic image characteristics such as the texture and intensity, (2) a minimum of computational requirements, and (3) a form that is naturally extendable to an appropriate probabilistic image model. The imaging system was modeled as a linear system with a separable three-dimensional point-spread function with an envelope of Gaussian curves in each dimension. The rough surface was modeled as a collection of discrete scatterers placed on the continuum and parametrized by a surface roughness and scatterer concentration. Models were evaluated by a visual comparison of actual and simulated images of a cadaveric lumbar vertebra. The gross shape of the vertebral surface was estimated from computed tomography images of the vertebra, and simulated images were generated using the models and the gross surface shape. Actual images were registered with the surface and simulated images to within 2 mm. The similarity of the actual and simulated images was quite remarkable considering the simplicity of the models. Differences between the images were less than those between two simulated images separated by 0.4 mm or one-fifth the registration error. Further assessment of the models would require a statistical approach not yet available. The models do, however, provide the basis for the development of a computationally tractable probabilistic image model for image analysis. Such a model will provide the means for a statistical evaluation of the system and surface models.     

A dyadic protocol for training complex skills: a replication using female participants

The effectiveness and efficiency of the active interlocked modeling (AIM) dyadic protocol in training complex skills has been extensively demonstrated. However, past evaluation studies have all used male participants exclusively. Consequently, the present study investigated the generalizability of the effectiveness and efficiency gains to women. We randomly assigned 108 female participants to either the AIM-dyad condition or a standard individual control training condition. The results supported the robustness and viability of the AIM protocol. Although their overall performance was lower than that obtained for men in previous studies, women trained in the AIM-dyad condition performed as well as those trained in the individual condition. Thus, the efficiency gains associated with the AIM-dyad protocol, which result from the ability to train two people simultaneously to reach the same performance level as a single person with no increase in training time or machine cost, are generalizable to female participants. The applied and basic research implications of the present study are discussed within the context of well-documented male/female differences in the performance of complex psychomotor tasks. For instance, given the number of women entering the workforce and the significant proportion of women in professions previously deemed to be male-dominated (e.g., air navigation), it is reassuring to know that sex differences in task performance do not necessarily imply sex differences in the effectiveness of training protocols.     

Role playing: An alternative to deception? A review of the evidence.

A review of the literature on role-playing and deception methodologies indicates that for its proponents, role playing promises to bypass a number of reactive dispositions and biases plaguing contemporary research. It also presumes an ethically superior E-S relationship. Those arguing against role playing focus upon its lack of realism and its capacity to provide generalizable data. Experimental comparisons of role playing and deception reveal serious shortcomings in the former. In addition, the ethical advantage is lost because the deception paradigm is the necessary criterion. Recent empirical developments substantiate the proposition that there are often major discrepancies between what a person thinks he will do or feels he should do, and what he actually does. Role playing counters recent trends toward naturalistic research designs, and is not seen as a promising methodological development. (77 ref.) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Nonrandom assignment and the analysis of covariance.

Discusses the appropriate use of the analysis of covariance for cases in which groups differ substantially on a variable that is entered as a covariate. The erroneous notions that groups must not differ significantly on the covariate and that covariates must be measured without error are rejected. Selective nonrandom assignment of Ss to groups on the basis of an observed variable that is measured with error can result in groups that differ substantially, but it is shown that conventional analysis of covariance provides unbiased estimates of the true treatment effects, in spite of the initial group differences. In other cases, correction for attenuation due to measurement error is required to obtain unbiased estimates of true treatment effects. (19 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Technical obsolescence.

Comments on I. L. Goldstein and P. Gilliam's (see record 1990-15901-001) article that cites evidence from H. G. Kaufman (see record 1979-02430-001) concerning technical obsolescence among engineers. As Kaufman noted, the usefulness of graduate degree work as a general approach to updating all engineers may be limited. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

1,3-Diacyl derivatives of imidazolidine and hexahydropyrimidine: II. Antimycotic activity

Series of 1,3-diacylated derivatives of imidazolidine and hexahydropyrimidine have been screened for antimycotic activity. Optimum activity was found for the 1,3-dihexanoyl derivatives in the imidazolidine series, with the higher and lower derivatives being much less active. In the hexahydropyrimidine series the 1,3-dipentanoyl, -dihexanoyl,-diheptanoyl and -dioctanoyl derivatives all exhibited a high degree of inhibition against all four of the test organisms. The latter wereTrichophyton rubrum, T violaceum, Microsporum gypseum andAspergillus flavus. Presented at the AOCS Meeting, Chicago, September 1970. So. Utiliz. Res. Dev. Div., ARS, USDA.     

Positron Emission Profiling Study of the Diffusion of 3-Methylpentane in Silicalite-1

The influence of the loading on the self-diffusion of 3-methylpentane within silicalite-1 has been studied with Positron Emission Profiling technique. A monotonous decrease in the self-diffusivities of alkane was observed with zeolite loading, which could be approximated by a stretched exponential. As a consequence, the apparent activation energy increases with partial pressure.