2,081 research outputs found
Formation Response of High Frequency Electromagnetic Waves
Core samples from rock formations respond to electromagnetic radiation based on an effective permittivity, which depends on the conductivity and permittivity of the constituent components of the rock, as well as the geometric structure of these constituents and the frequency of the radiation. This study analyzes the effect, for radiation of 1 to 100 Mhz, of discrete inclusions having a different permittivity from the surrounding medium. The focus is on the effect of certain geometric features, namely, the individual size of the inclusions, their overall volume fraction, the presence of sharp edges, and their aspect ratio.
It is found that the volume fraction has the strongest impact on the effective permittivity, linear at first but higher order at higher volume fractions. The aspect ratio of the inclusions has a moderate effect, which is exaggerated in the extreme case of needle-like inclusions, and which can also be seen in a stronger nonlinearity. There is also a possibility that some features in the shape of the inclusion boundaries may influence the frequency dependence of the effective permittivity. Inclusion size and sharp edges have negligible effect
The Role of the Facilitator in Computer-Supported Environments: A Critical Incidents Study
The Role of the Facilitator in Computer-supported Environments
This multiphased study represents a rigorous exploration of the role of the facilitator in computer-supported environments. The purpose of the study was to identify and empirically measure the importance of the critical dimensions of the facilitator\u27s role. The study examined the following research questions:
1) What are the critical dimensions and their related behaviors that contribute to the role of the effective facilitator in face-to-face computer supported environments?
2) Are there impacts on or differences in critical facilitator role dimensions/behaviors when facilitating with different types of group support systems (GSS) (computer based technology to support group work)?
The critical incidents methodology was employed to collect two hundred thirty-five reports of facilitator experiences from fifty experienced facilitators in computer supported environments. One hundred forty-six (146) generic and one thousand two hundred ninety-eight (1298) specific facilitator behaviors were identified. These behaviors were then categorized into critical role dimensions.
The results of Phase I of the study indicated the existence of sixteen critical role dimensions. The empirical measures of importance in Phase II produced significant findings, identifying Planning and Designing Meetings as the most important facilitator role dimension overall. Other extremely important dimensions were identified. Statistically significant agreement on the relative importance of a number of role dimensions, along with significant differences across technology on mean importance rankings were identified. These differences were quite dramatic considering the small sample size.
The study findings have important implications for organizational practitioners and researchers alike. This study is the first to identify and ground the critical role dimensions of the facilitator\u27s role in computer-supported environments. These precise descriptions furnish a starting point for future research on the role and process of facilitation in both traditional and electronic contexts. The richly grounded dimensions also provide an excellent practical foundation for the development of behavior based selection criteria, performance measures and skill based facilitator training programs
Characteristics of Effective GSS Facilitators
As businesses increase their use of groups to solve problems, the importance of strong group facilitation skills has increased. This paper investigates the characteristics of high-performing group facilitators versus low-performing group facilitators. The characteristics investigated represent two broad areas of interest: general facilitator background and skills possessed by the facilitator. The facilitator background factors that proved to be good predictors of high performance included: overall experience and number of computer-supported meeting facilitated. The skills possessed by high performers included: plans and designs meetings, demonstrates flexibility, and listens to, clarifies, and integrates information. The analysis provides a rule for accurately predicting whether a facilitator is a high-performer or a low-performer more than 77% of the time
Investigation of strength limiting mechanisms in aramid fibers
Aramid fibers owe their high tensile strength and stiffness to their orderly fibrillar structure. The synergistic effect of individual fibrils comprising an aramid fiber, and the interfibrillar interactions determine the strength of an individual fiber. In order to study the existence and role of statistical defects in failure initiation of aramid fibers, quasi-static tensile tests were performed with individual fibers of different molecular compositions and gage lengths in the range of 100 µm–10 mm. The experimental results pointed out to a relative insensitivity of the tensile strength to the fiber gage length, which suggested that failure initiation is governed by processes and/or flaws active at length scales well below micron scale. Therefore, differences in tensile strength between the particular types of aramid fibers discussed in this study were attributed to interfibrillar interactions. The magnitude of the latter was assessed by longitudinal crack growth experiments with individual fibers, as interfibrillar interactions are expected to be similar to the van der Waals interactions between the hydrogen bonded macromolecular sheets comprising the aramid fibers. The initial fracture experiments showed stable crack propagation under relatively constant force taking place for very large lengths of individual fibers. This presentation will provide the current results on the cohesive energy measurements on two types of aramid fibers designed to provide high tensile strength
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Changes in the Carbon and Energy Balance of the Sagebrush Steppe Ecosystem of the Pacific Northwest - White Paper
We propose a multi-agency study to understand the impacts of land-use change on the carbon and energy balance of the Pacific Northwest. By integrating data for the carbon and energy fluxes across different scales within each land-use type, we will develop more accurate input parameters for the regional climate models. The product of this study will address two priorities recommended by the National Academy of Sciences; 1) reduce uncertainties in climate change projections and 2) provide a more definitive evaluation of long-term changes
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Risk-based approach for controlling beryllium exposure in a manufacturing environment
There are many diverse uses for beryllium in both military and industrial applications. Unfortunately, there are certain worker health risks associated with the manufacture and production of beryllium products. Respiratory illnesses due to prolonged contact with beryllium particulate are of paramount concern. However, these health risks can be controlled provided that the appropriate protective measures to prevent worker exposure from beryllium are in place. But it is no1 always a straightforward process to identify exactly what the beryllium protective measures should be in order to realize a true risk savings. Without prudent attention to a systematic inquiry and suitable evaluative criteria, a program for controlling beryllium health risks can be lacking in completeness and overall effectiveness. One approach that took into account the necessary ingredients for risk-based determination of beryllium protective measures was developed for a beryllium operation at a Department of Energy (DOE) facility. The methodological framework that was applied at this facility, as well as a discussion of the final beryllium protective measures that were determined by this approach will be presented. Regulatory aspects for working with beryllium, as well as a risk-assessment strategy for ranking beryllium-handling activities with respect to exposure potential will also be discussed. The presentation will conclude with a synopsis of lessons-learned as gleaned from this case study, as well as providing the participants with a constructive blueprint that can be adapted to other processes involving beryllium
Black Border Increases Stomoxys calcitrans Catch on White Sticky Traps
Publication history: Accepted - 1 February 2018; Published online: 2 February 2018Stable fly, Stomoxys calcitrans, is a biting fly that can cause severe irritation to livestock resulting in reduced productivity. The most common method of monitoring S. calcitrans is through the use of sticky traps and many designs have been developed using different colours and materials such as alsynite fibreglass and polypropylene sheeting. Laboratory experiments and some field experimentation have demonstrated that colour contrast can attract S. calcitrans. However, this response has not been fully utilised in trap design. To test that simple colour contrast could increase trap efficacy, white sticky traps were mounted on three differently coloured backgrounds (white, yellow, and black) and positioned at five sites on a mixed livestock farm. White sticky traps on a black background caught significantly more S. calcitrans than the yellow or white backgrounds. An incidental result was that Pollenia sp. were caught in greater numbers on the yellow framed traps. The reasons for S. calcitrans attraction to black–white contrast are most likely due to conspicuousness in the environment although the extent to which flies are using this feature as a host-location cue or a perching site are unknown.This project was funded by the Department of Agriculture, Environment and Rural Affairs (Northern Ireland) through the Evidence and Innovation Strategy (Project 16/3/07-48109)
Small ruminant lentivirus genetic subgroups associate with sheep TMEM154 genotypes.
Abstract: Small ruminant lentiviruses (SRLVs) are prevalent in North American sheep and a major cause of production losses for the U.S. sheep industry. Sheep susceptibility to SRLV infection is influenced by genetic variation within the ovine transmembrane 154 gene (TMEM154). Animals with either of two distinct TMEM154 haplotypes that both encode glutamate at position 35 of the protein (E35) are at greater risk of SRLV infection than those homozygous with a lysine (K35) haplotype. Prior to this study, it was unknown if TMEM154 associations with infection are influenced by SRLV genetic subgroups. Accordingly, our goals were to characterize SRLVs naturally infecting sheep from a diverse U.S. Midwestern flock and test them for associations with TMEM154 E35K genotypes. Two regions of the SRLV genome were targeted for proviral amplification, cloning, sequence analysis, and association testing with TMEM154 E35K genotypes: gag and the transmembrane region of env. Independent analyses of gag and env sequences showed that they clustered in two subgroups (1 and 2), they were distinct from SRLV subtypes originating from Europe, and that subgroup 1 associated with hemizygous and homozygous TMEM154 K35 genotypes and subgroup 2 with hemi- and homozygous E35 genotypes (gag p < 0.001, env p = 0.01). These results indicate that SRLVs in the U.S. have adapted to infect sheep with specific TMEM154 E35K genotypes. Consequently, both host and SRLV genotypes affect the relative risk of SRLV infection in sheep
Together forever? Explaining exclusivity in party-firm relations
Parties and firms are the key actors of representative democracy and capitalism respectively and the dynamic of attachment between them is a central feature of any political economy. This is the first article to systematically analyse the exclusivity of party-firm relations. We consider exclusivity at a point in time and exclusivity over time. Does a firm have a relationship with only one party at a given point in time, or is it close to more than one party? Does a firm maintain a relationship with only one party over time, or does it switch between parties? Most important, how do patterns of exclusivity impact on a firm’s ability to lobby successfully? We propose a general theory, which explains patterns of party-firm relations by reference to the division of institutions and the type of party competition in a political system. A preliminary test of our theory with Polish survey data confirms our predictions, establishing a promising hypothesis for future research
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