Showing papers by "University of New Brunswick published in 2000"

Word-of-Mouth Processes within a Services Purchase Decision Context

Abstract: This article investigates the processes of word of mouth (WOM) within a services purchase decision context. The authors argue that to understand these processes, researchers must examine the role of interpersonal influences in the traditional WOM models based within the noninterpersonal paradigm. As a result of the current investigation, three distinct relations emerge: first, the effect of the noninterpersonal forces (receiver’s expertise, receiver’s perceived risk, and sender’s expertise) on the influence of WOM on service purchase decisions; second, the effect of the interpersonal forces (ties strength and how actively WOM is sought) on the influence of WOM on service purchase decisions; and third, the effects of noninterpersonal forces on interpersonal forces. Managerial implications and avenues for future research are addressed.

Secular trends in the body mass index of Canadian children

Abstract: Background: Various changes in society have created the opportunity for more sedentary behaviour and the consumption of food that is high in kilojoules, which may lead to a progressive increase in body mass over time. The purpose of this study was to examine secular changes in the body mass index (BMI) of Canadian children between 1981 and 1996. Methods: Nationally representative data from the 1981 Canada Fitness Survey, the 1988 Campbell9s Survey on the Well-being of Canadians and the 1996 National Longitudinal Survey of Children and Youth were used in the analysis. Regression analyses were used to assess population changes in BMI from 1981 to 1996 for children aged 7–13 years. Changes in the distribution of BMI results were evaluated by plotting the residuals from regression analyses of BMI on age, assessed separately by sex, using the 1981 data as baseline. The proportions of children exceeding the 85th and 95th age- and sex-specific percentiles from the 1981 (baseline) data were also calculated. Results: Since 1981, BMI has increased at the rate of nearly 0.1 kg/m 2 per year for both sexes at most ages, indicating a clear secular trend toward an increase in BMI of Canadian children. The prevalence of overweight among boys increased from 15% in 1981 to 28.8% in 1996 and among girls from 15% to 23.6%. The prevalence of obesity in children more than doubled over that period, from 5% to 13.5% for boys and 11.8% for girls. Interpretation: Secular trends indicate that Canadian children aged 7–13 years are becoming progressively overweight and obese.

Structure of the bacteriophage φ29 DNA packaging motor

Abstract: Motors generating mechanical force, powered by the hydrolysis of ATP, translocate double-stranded DNA into preformed capsids (proheads) of bacterial viruses and certain animal viruses. Here we describe the motor that packages the double-stranded DNA of the Bacillus subtilis bacteriophage phi29 into a precursor capsid. We determined the structure of the head-tail connector--the central component of the phi29 DNA packaging motor--to 3.2 A resolution by means of X-ray crystallography. We then fitted the connector into the electron densities of the prohead and of the partially packaged prohead as determined using cryo-electron microscopy and image reconstruction analysis. Our results suggest that the prohead plus dodecameric connector, prohead RNA, viral ATPase and DNA comprise a rotary motor with the head-prohead RNA-ATPase complex acting as a stator, the DNA acting as a spindle, and the connector as a ball-race. The helical nature of the DNA converts the rotary action of the connector into translation of the DNA.

Limits to Exhaustive Exercise in Fish

Abstract: Exercise to exhaustion leads to severe metabolic, acid-base and ionic changes in fish. It has been shown that several abiotic and biotic factors can limit burst exercise performance and the recovery process in fish. This article reviews the importance of body size, temperature, fasting/starvation and training on the ability of fish to perform and recover from exhaustive exercise. It is concluded that the constraints placed on a fish prior to and following exercise reflects the large intra-specific variability in the physiological response to exercise in fish.

The Role of Peers in the Emergence of Heterosexual Romantic Relationships in Adolescence.

Abstract: Adolescents' peer structures and the quality of their friendships were explored as antecedents of romantic relationships. Longitudinal data were gathered in a sample of 180 high school students over a 3-year period from grade 9 to grade 11. Consistent with Dunphy (1963), small groups of close friends were predictive of other-sex peer networks which were, in turn predictive of the emergence of future romantic relationships. Indirect effects were found for same-sex groups of close friends and same-sex networks. Consistent with Furman and Wehner (1994), the qualitative features of relationships with both friends and romantic partners were predictive of the qualitative features of subsequent romantic experiences. These linkages suggest ways in which peer relationships may support romantic development at this stage of the life cycle.

Fuzzy EMG classification for prosthesis control

Abstract: Proposes a fuzzy approach to classify single-site electromyograph (EMG) signals for multifunctional prosthesis control. While the classification problem is the focus of this paper, the ultimate goal is to improve myoelectric system control performance, and classification is an essential step in the control. Time segmented features are fed to a fuzzy system for training and classification. In order to obtain acceptable training speed and realistic fuzzy system structure, these features are clustered without supervision using the Basic Isodata algorithm at the beginning of the training phase, and the clustering results are used in initializing the fuzzy system parameters. Afterwards, fuzzy rules in the system are trained with the back-propagation algorithm. The fuzzy approach was compared with an artificial neural network (ANN) method on four subjects, and very similar classification results were obtained. It is superior to the latter in at least three points: slightly higher recognition rate; insensitivity to overtraining; and consistent outputs demonstrating higher reliability. Some potential advantages of the fuzzy approach over the ANN approach are also discussed.

PRACTICAL MAXIMUM PSEUDOLIKELIHOOD FOR SPATIAL POINT PATTERNS (with Discussion)

Abstract: Summary This paper describes a technique for computing approximate maximum pseudolikelihood estimates of the parameters of a spatial point process. The method is an extension of Berman & Turner’s (1992) device for maximizing the likelihoods of inhomogeneous spatial Poisson processes. For a very wide class of spatial point process models the likelihood is intractable, while the pseudolikelihood is known explicitly, except for the computation of an integral over the sampling region. Approximation of this integral by a finite sum in a special way yields an approximate pseudolikelihood which is formally equivalent to the (weighted) likelihood of a loglinear model with Poisson responses. This can be maximized using standard statistical software for generalized linear or additive models, provided the conditional intensity of the process takes an ‘exponential family’ form. Using this approach a wide variety of spatial point process models of Gibbs type can be fitted rapidly, incorporating spatial trends, interaction between points, dependence on spatial covariates, and mark information.

Adaptive set intersections, unions, and differences

Abstract: Motivated by boolean queries in text database systems, we consider the problems of finding the intersection, union, or difference of a collection of sorted sets. While the worst-case complexity of these problems is straightforward , we consider a notion of complexity that depends on the particular instance. We develop the idea of a proof that a given set is indeed the correct answer. Proofs, and in particular shortest proofs, are characterized. We present adaptive algorithms that make no a priori assumptions about the problem instance, and show that their running times are within a constant factor of optimal with respect to a natural measure of the difficulty of an instance. In the process, we develop a framework for designing and evaluating adaptive algorithms in the comparison model. 1 Introduction and Overview Our work can be seen in the general context of performing searches quickly in a database or data warehousing environment. The broad issue is that of characterizing what type of join operations can be performed without scanning the relations involved or actually materializing intermediate relations. The specific problem addressed here can be seen in that context or in the context of performing a web search, or a search in another large text database, for documents containing some or all of a set of keywords. For each keyword we are given the set of references to documents in which it occurs [2, 6, 9]. These sets are stored in some natural order, such as document date. In practice, the sets are large. For example, the average word from user query logs matches approximately a million documents on the AltaVista web search engine. Of course, one would hope that the answer to the query is small, particularly if the query is an intersection. It may also be expected that the elements of such an intersection are not spread uniformly through the initial

Pollen‐based biomes for Beringia 18,000, 6000 and 0 14C yr bp†

Abstract: The objective biomization method developed by Prentice et al. (1996) for Europe was extended using modern pollen samples from Beringia and then applied to fossil pollen data to reconstruct palaeovegetation patterns at 6000 and 18,000 14C yr bp. The predicted modern distribution of tundra, taiga and cool conifer forests in Alaska and north-western Canada generally corresponds well to actual vegetation patterns, although sites in regions characterized today by a mosaic of forest and tundra vegetation tend to be preferentially assigned to tundra. Siberian larch forests are delimited less well, probably due to the extreme under-representation of Larix in pollen spectra. The biome distribution across Beringia at 6000 14C yr bp was broadly similar to today, with little change in the northern forest limit, except for a possible northward advance in the Mackenzie delta region. The western forest limit in Alaska was probably east of its modern position. At 18,000 14C yr bp the whole of Beringia was covered by tundra. However, the importance of the various plant functional types varied from site to site, supporting the idea that the vegetation cover was a mosaic of different tundra types.

Determination of Activation Energy for Glass Transition of an Epoxy Adhesive Using Dynamic Mechanical Analysis

Abstract: The activation energy associated with the glass transition relaxation of an epoxy system has been determined by using the three-point bending clamp provided in the recently introduced TA Instruments DMA 2980 dynamic mechanical analyzer. A mathematical expression showing the dependency of modulus measurements on the sample properties and test conditions has also been derived. The experimental results showed that the evaluation of activation energy is affected by the heating rate and test frequency, as well as the criterion by which the glass transition temperature (Tg) is established. It has been found that the activation energy based on the loss tangent (tanδ) peak is more reliable than on the loss modulus (E2) peak, as long as the dynamic test conditions do not cause excessive thermal lags.

(Gas-)liquid-solid circulating fluidized beds and their potential applications to bioreactor engineering

Abstract: Compared with conventional fluidized beds, circulating fluidized beds have many advantages including better interfacial contacting and reduced backmixing (Lim et al, 1995) While there are many reports on the gas—solid circulating fluidized systems, liquid—solid and gas—liquid—solid circulating fluidized bed systems have been scantily studied However, extending current knowledge obtained in gas—solid systems to liquid—solids and gas—liquid—solid three-phase systems is shown to open new horizons for applications of circulating fluidized bed technology and expected to lead to the development of highly efficient liquid—solid and gas—liquid—solid reactors, especially for the ever growing field of biotechnology In order to fully appreciate the potential of those two types of liquid phase circulating fluidized beds, recent progress is reviewed in this article Their potential applications to biochemical processes are also discussed Comparativement aux lits fluidises classiques, les lits fluidises circulants offrent de nombreux avantages, dont un meilleur contact interfacial et un retromelange reduit (Lim et al, 1995) Bien qu'un nombre important d'articles paraissent sur les systemes fluidises circulants gaz—solide, les systemes a lits fluidises circulants liquide—solide et gaz—liquide—solide ont fait l'objet de peu d'etudes On montre cependant que l'utilisation des connaissances actuelles sur les systemes gaz—solide pour les etendre aux systemes liquide—solides et aux systemes triphasiques gaz—liquide—solide ouvre de nouveaux horizons a l'application de la technologie du lit fluidise circulant et devrait permettre le developpement de reacteurs liquide—solide et gaz—liquide—solide hautement efficaces, en particulier pour le secteur de la biotechnologie toujours en croissance Afin d'apprecier pleinement le potentiel de ces deux types de lits fluidises circulants en phase liquide, les derniers progres en la matiere sont passes en revue dans cet article Leurs applications potentielles aux procedes biochimiques sont egalement examinees

GPS Ambiguity Resolution and Validation: Methodologies, Trends and Issues

Abstract: Resolving the GPS carrier-phase ambiguities has been a continuing challenge for sub -centimeter-level highprecision GPS positioning. Once the integer ambiguities are fixed correctly, the carrie r-phase observations are conceptually turned into sub-centimeter-level high-precision range measurements making it possible to attain high-precision positioning solutions. Consequently, this topic has been a rich source of GPS -research over the last decade. A brief review of the previous work on ambiguity resolution and validation which has been carried out by many research groups from all over the world is presented in this paper. For a general understanding of these contributions, we have classified the ambiguity resolution techniques in terms of their characteristics. Current research trends and issues in ambiguity resolution and validation are described and a bibliography of representative papers is provided.

Test of a new lacunarity estimation method for image texture analysis

Abstract: Based on a differential box counting method and a gliding-box algorithm, a new method for estimating the lacunarity of grey scale digital image surfaces is introduced, and directionality of lacunarity defined. To test the performance of the new lacunarity measure, a Brodatz texture image mosaic is employed and several other texture analysis approaches are also applied to the texture mosaic. Quantitative comparison shows that the new lacunarity estimation method for grey-scale images can provide more accurate texture measurements than some existing lacunarity measures, the grey level co-occurrence matrix based texture measures, the Min-Max operator, and the fractal dimension.

The Relation Between Experience and Spatial Performance in Men and Women

Abstract: The purpose of the present study was to test the hypothesis that environmental factors affect the magnitude of gender differences in spatial performance only when the tasks used are susceptible to the influence of such factors. Two hundred and ninety White middle-class undergraduate students (165 females, 125 males) completed the Vandenberg and Kuse Mental Rotations Test (MRT), a paper and pencil version of the Water Level Task (WLT), and toys and sports preference questionnaires. Results revealed that males outperformed females on both spatial tests. In addition, a main effect of toys preference showed that participants with a spatial toys preference outperformed those with a nonspatial preference on both the MRT and the WLT. This main effect was qualified by an interaction between this factor and gender. The interaction was found only on the WLT and showed that gender differences were only significant in participants with a nonspatial preference. An interaction of sports preference and gender was also observed. This interaction revealed that, in contrast to what was obtained with toys, gender differences on both spatial tests were significant only in participants with a spatial sports preference. Implications of these findings with regard to the development of gender differences in spatial abilities are discussed.

The effect of photoperiod, tank colour and light intensity on growth of larval haddock

Abstract: In two separate experiments, haddock (Melanogrammus aeglefinus) larvae were raised under different photoperiods (24L : 0D or 15L : 9D), or different combinations of tank colour (black or white) and light intensity (1.1 μmol s−1 m−2 or 18 μmol s−1 m−2). Growth (0.8% day−1 in standard length; 2.9% day−1 in body area) and survival (2%) were not significantly different between photoperiod treatments after 35 days. Larval survival was greater in white versus black tanks after 41 days (2% versus l%, respectively). Growth of larvae was impaired in black tanks at low (1.1 μmol s−1 m−2) light intensity (0.8% day−1 in standard length and 2.2% day−1 in body area versus 1.1% day 21 in standard length and 3.1% day−1 in body area, for all other treatments). Transmission and reflection of light was low in black tanks at low incident light, and there was very little upwelling light. The resultant poor prey to background contrast probably resulted in larvae being unable to consume sufficient food to sustain a level of growth comparable to that in other treatments.

Empathic Listening: Reports on the Experience of being Heard

Abstract: This qualitative study explores empathic listening from the vantage point of 5 female clients engaged in consecutive therapeutic relationships with two different therapists, a male and a female. Pr...

Eye-hand co-ordination with force feedback

Abstract: The term Eye-hand co-ordination refers to hand movements controlled with visual feedback and reinforced by hand contact with objects. A correct perspective view of a virtual environment enables normal eye-hand co-ordination skills to be applied. But is it necessary for rapid interaction with 3D objects? A study of rapid hand movements is reported using an apparatus designed so that the user can touch a virtual object in the same place where he or she sees it. A Fitts tapping task is used to assess the effect of both contact with virtual objects and real-time update of the centre of perspective based on the user's actual eye position. A Polhemus tracker is used to measure the user's head position and from this estimate their eye position. In half of the conditions, head tracked perspective is employed so that visual feedback is accurate while in the other half a fixed eye-position is assumed. A Phantom force feedback device is used to make it possible to touch the targets in selected conditions. Subjects were required to change their viewing position periodically to assess the importance of correct perspective and of touching the targets in maintaining eye-hand co-ordination, The results show that accurate perspective improves performance by an average of 9% and contact improves it a further 12%. A more detailed analysis shows the advantages of head tracking to be greater for whole arm movements in comparison with movements from the elbow.

Maximizing workforce diversity in project teams: a network flow approach

Abstract: Several social, economic and political factors have contributed to the increasing diversity of today's workforce. In addition, in an era when organizations are continuously redesigning their work and restructuring their operations to achieve their goals with fewer resources, performing work in teams has become commonplace. These trends have increased the need for managing diverse work teams effectively. There are several existing models in the management science literature that help managers to assign employees to work groups in order to maximize the groups' diversity and hence, facilitate their effectiveness. This paper introduces a new model that recasts the problem of managing diversity in a different way: it is assumed that the population comes partitioned into `families' with a high degree of intra-familial similarity and inter-familial dissimilarity. The objective of the assignment then is to disperse these family members as evenly into the workgroups as possible. A little known network flow problem, known as the dining problem, is used to develop an efficient algorithm to produce solutions to this new model. This is followed by a report on an experimental application of the developed model to assign Master of Business Administration students in a business school to different projects in a course. As a part of this empirical report, an attractive feature of this model is also demonstrated; namely, how to conduct sensitivity analysis to determine the optimal levels of diversity in the presence of resource constraints. Finally, the paper concludes by discussing limitations of this new model and how they may be addressed in future research on this topic.

A survey of organic volatile species in comet C/1999 H1 (Lee) using NIRSPEC at the Keck Observatory

Abstract: The organic volatile composition of the long-period comet C/1999 H1 (Lee) was investigated using the —rst of a new generation of cross-dispersed cryogenic infrared spectrometers (NIRSPEC, at the Keck Observatory atop Mauna Kea, HI). On 1999 August 19¨21 the organics spectral region (2.9¨3.7 km) was completely sampled at both moderate and high dispersion, along with the CO fundamental region (near 4.67 km), revealing emission from water, carbon monoxide, methanol, methane, ethane, acetylene, and hydrogen cyanide. Many new multiplets from OH in the 1¨0 band were seen in prompt emission, and numerous new spectral lines were detected. Several spectral extracts are shown, and global production rates are presented for seven parent volatiles. Carbon monoxide is strongly depleted in comet Lee relative to comets Hyakutake and Hale-Bopp, demonstrating that chemical diversity occurred in the giant

Making the Sacred Safe: Woman Abuse and Communities of Faith

Abstract: Apres quelques precautions en matiere d'attitude mentale et d'interpretation de la realite, et apres avoir evoque quelques aspects de son parcours professionnel, l'A. examine la question de la violence domestique a l'encontre des femmes selon six points de vue : du feminisme universitaire ; des travailleurs sociaux des lieux d'accueil ; de la famille chretienne ; du clerge ; d'une congregation religieuse ; de la femme battue elle-meme. Elle entend ainsi en confronter les aspects spirituels et pratiques, dans l'optique de surmonter certaines contradictions existant entre les approches religieuses et laiques