Showing papers by "University of Calgary published in 2002"

A Descriptive Framework of Workspace Awareness for Real-Time Groupware

Abstract: Supporting awareness of others is an idea that holds promise for improving the usability of real-time distributed groupware. However, there is little principled information available about awareness that can be used by groupware designers. In this article, we develop a descriptive theory of awareness for the purpose of aiding groupware design, focusing on one kind of group awareness called i>workspace awareness. We focus on how small groups perform generation and execution tasks in medium-sized shared workspaces – tasks where group members frequently shift between individual and shared activities during the work session. We have built a three-part framework that examines the concept of workspace awareness and that helps designers understand the concept for purposes of designing awareness support in groupware. The framework sets out elements of knowledge that make up workspace awareness, perceptual mechanisms used to maintain awareness, and the ways that people use workspace awareness in collaboration. The framework also organizes previous research on awareness and extends it to provide designers with a vocabulary and a set of ground rules for analysing work situations, for comparing awareness devices, and for explaining evaluation results. The basic structure of the theory can be used to describe other kinds of awareness that are important to the usability of groupware.

Placental-specific IGF-II is a major modulator of placental and fetal growth

Abstract: Imprinted genes in mammals are expressed from only one of the parental chromosomes, and are crucial for placental development and fetal growth1,2,3,4. The insulin-like growth factor II gene (Igf2) is paternally expressed in the fetus and placenta5. Here we show that deletion from the Igf2 gene of a transcript (P0)6,7 specifically expressed in the labyrinthine trophoblast of the placenta leads to reduced growth of the placenta, followed several days later by fetal growth restriction. The fetal to placental weight ratio is thus increased in the absence of the P0 transcript. We show that passive permeability for nutrients of the mutant placenta is decreased, but that secondary active placental amino acid transport is initially upregulated, compensating for the decrease in passive permeability. Later the compensation fails and fetal growth restriction ensues. Our study provides experimental evidence for imprinted gene action in the placenta that directly controls the supply of maternal nutrients to the fetus, and supports the genetic conflict theory of imprinting8. We propose that the Igf2 gene, and perhaps other imprinted genes, control both the placental supply of, and the genetic demand for, maternal nutrients to the mammalian fetus.

Confocal microwave imaging for breast cancer detection: localization of tumors in three dimensions

Abstract: The physical basis for breast tumor detection with microwave imaging is the contrast in dielectric properties of normal and malignant breast tissues. Confocal microwave imaging involves illuminating the breast with an ultra-wideband pulse from a number of antenna locations, then synthetically focusing reflections from the breast. The detection of malignant tumors is achieved by the coherent addition of returns from these strongly scattering objects. In this paper, we demonstrate the feasibility of detecting and localizing small (<1 cm) tumors in three dimensions with numerical models of two system configurations involving synthetic cylindrical and planar antenna arrays. Image formation algorithms are developed to enhance tumor responses and reduce early- and late-time clutter. The early-time clutter consists of the incident pulse and reflections from the skin, while the late-time clutter is primarily due to the heterogeneity of breast tissue. Successful detection of 6-mm-diameter spherical tumors is achieved with both planar and cylindrical systems, and similar performance measures are obtained. The influences of the synthetic array size and position relative to the tumor are also explored.

Biofilm bacteria: formation and comparative susceptibility to antibiotics

Abstract: The Calgary Biofilm Device (CBD) was used to form bacterial biofilms of selected veterinary gram-negative and gram-positive pathogenic bacteria from cattle, sheep, pigs, chicken, and turkeys The minimum inhibitory concentration (MIC) and minimum biofilm eradication concentration (MBEC) of ampicillin, ceftiofur, cloxacillin, oxytetracycline, penicillin G, streptomycin, tetracycline, enrofloxacin, erythromycin, gentamicin, tilmicosin, and trimethoprim-sulfadoxine for gram-positive and -negative bacteria were determined Bacterial biofilms were readily formed on the CBD under selected conditions The biofilms consisted of microcolonies encased in extracellular polysaccharide material Biofilms composed of Arcanobacterium (Actinomyces) pyogenes, Staphylococcus aureus, Staphylococcus hyicus, Streptococcus agalactiae, Corynebacterium renale, or Corynebacterium pseudotuberculosis were not killed by the antibiotics tested but as planktonic bacteria they were sensitive at low concentrations Biofilm and planktonic Streptococcus dysgalactiae and Streptococcus suis were sensitive to penicillin, ceftiofur, cloxacillin, ampicillin, and oxytetracycline Planktonic Escherichia coli were sensitive to enrofloxacin, gentamicin, oxytetracycline and trimethoprim/ sulfadoxine Enrofloxacin and gentamicin were the most effective antibiotics against E coli growing as a biofilm Salmonella spp and Pseudomonas aeruginosa isolates growing as planktonic populations were sensitive to enrofloxacin, gentamicin, ampicillin, oxytetracycline, and trimethoprim/sulfadoxine, but as a biofilm, these bacteria were only sensitive to enrofloxacin Planktonic and biofilm Pasteurella multocida and Mannheimia haemolytica had similar antibiotic sensitivity profiles and were sensitive to most of the antibiotics tested The CBD provides a valuable new technology that can be used to select antibiotics that are able to kill bacteria growing as biofilms

Canada's recreational fisheries: the invisible collapse?

Abstract: Fishing for recreation is a popular activity in many parts of the world and this activity has led to the development of a sector of substantial social and economic value worldwide. The maintenance of this sector depends on the ability of aquatic ecosystems to provide fishery harvest. We are currently witnessing the collapse of many commercial marine fisheries due to over-exploitation. Recreational fisheries are typically viewed as different from commercial fisheries in that they are self-sustaining and not controlled by the social and economic forces of the open market that have driven many commercial fisheries to collapse. Here we reject the view that recreational and commercial fisheries are inherently different and demonstrate several mechanisms that can lead to the collapse of recreational fisheries. Data from four high profile Canadian recreational fisheries show dramatic declines over the last several decades yet these declines have gone largely unnoticed by fishery scientists, managers, an...

Improving the Assessment of Outcomes in Stroke: Use of a Structured Interview to Assign Grades on the Modified Rankin Scale

Abstract: Background and Purpose— The modified Rankin Scale is widely used to assess changes in activity and lifestyle after stroke, but it has been criticized for its subjectivity. The purpose of the present study was to compare conventional assessment on the modified Rankin Scale with assessment through a structured interview. Methods— Sixty-three patients with stroke 6 to 24 months previously were interviewed and graded independently on the modified Rankin Scale by 2 observers. These observers then underwent training in use of a structured interview for the scale that covered 5 areas of everyday function. Eight weeks after the first assessment, the same observers reassessed 58 of these patients using the structured interview. Results— Interrater reliability was measured with the κ statistic (weighted with quadratic weights). For the scale applied conventionally, overall agreement between the 2 raters was 57% (κw=0.78); 1 rater assigned significantly lower grades than the other (P=0.048). On the structured interv...

Development of Spontaneous Airway Changes Consistent with Human Asthma in Mice Lacking T-bet

Abstract: Human asthma is associated with airway infiltration by T helper 2 (TH2) lymphocytes. We observed reduced expression of the TH1 transcription factor, T-bet, in T cells from airways of patients with asthma compared with that in T cells from airways of nonasthmatic patients, suggesting that loss of T-bet might be associated with asthma. Mice with a targeted deletion of the T-bet gene and severe combined immunodeficient mice receiving CD4+ cells from T-bet knockout mice spontaneously demonstrated multiple physiological and inflammatory features characteristic of asthma. Thus, T-bet deficiency, in the absence of allergen exposure, induces a murine phenotype reminiscent of both acute and chronic human asthma.

Enhancing breast tumor detection with near-field imaging

Abstract: This article outlines the main features of active, passive, and hybrid systems under investigation for breast cancer detection. Our main focus is on active microwave systems, in particular microwave tomography and confocal microwave imaging.

Edith Penrose's contribution to the resource-based view of strategic management

Abstract: Edith Penrose's (1959) book, The Theory of the Growth of the Firm, is considered by many scholars in the strategy field to be the seminal work that provided the intellectual foundations for the modern, resource-based theory of the firm. However, the present paper suggests that Penrose's direct or intended contribution to resource-based thinking has been misinterpreted. Penrose never aimed to provide useful strategy prescriptions for managers to create a sustainable stream of rents; rather, she tried to rigorously describe the processes through which firms grow. In her theory, rents were generally assumed not to occur. If they arose this reflected an inefficient macro-level outcome of an otherwise efficient micro-level growth process. Nevertheless, her ideas have undoubtedly stimulated ‘good conversation’ within the strategy field in the spirit of Mahoney and Pandian (1992); their emerging use by some scholars as building blocks in models that show how sustainable competitive advantage and rents can be achieved is undeniable, although such use was never intended by Edith Penrose herself. Copyright © 2002 John Wiley & Sons, Ltd.

Person and Number in Pronouns: A Feature-Geometric Analysis

Abstract: The set of person and number features necessary to characterize the pronominal paradigms of the world's languages is highly constrained, and their interaction is demonstrably systematic. We develop a geometric representation of morphosyntactic features which provides a principled explanation for the observed restrictions on these paradigms. The organization of this geometry represents the grammaticalization of fundamental cognitive categories, such as reference, plurality, and taxonomy. We motivate the geometry through the analysis of pronoun paradigms in a broad range of genetically distinct languages.

Validity of information on comorbidity derived rom ICD-9-CCM administrative data.

Abstract: The comorbidity variables that constitute the Charlson index are widely used in health care research using administrative data. However, little is known about the validity of administrative data in these comorbidities. The agreement between administrative hospital discharge data and chart data for the recording of information on comorbidity was evaluated. The predictive ability of comorbidity information in the two data sets for predicting in-hospital mortality was also compared.

Capitalizing on Diversity: Interpersonal Congruence in Small Work Groups:

Abstract: We examine interpersonal congruence, the degree to which group members see others in the group as others see themselves, as a moderator of the relationship between diversity and group effectiveness...

Nitrogen retention in rivers: model development and application to watersheds in the northeastern U.S.A.

Abstract: A regression model (RivR-N) was developed that predicts the proportion of N removed from streams and reservoirs as an inverse function of the water displacement time of the water body (ratio of water body depth to water time of travel). When applied to 16 drainage networks in the eastern U.S., the RivR-N model predicted that 37% to 76% of N input to these rivers is removed during transport through the river networks. Approximately half of that is removed in 1st through 4th order streams which account for 90% of the total stream length. The other half is removed in 5th order and higher rivers which account for only about 10% of the total stream length. Most N removed in these higher orders is predicted to originate from watershed loading to small and intermediate sized streams. The proportion of N removed from all streams in the watersheds (37-76%) is considerably higher than the proportion of N input to an individual reach that is removed in that reach (generally <20%) because of the cumulative effect of continued nitrogen removal along the entire flow path in downstream reaches. This generally has not been recognized in previous studies, but is critical to an evaluation of the total amount of N removed within a river network. At the river network scale, reservoirs were predicted to have a minimal effect on N removal. A fairly modest decrease (<10 percentage points) in the N removed at the river network scale was predicted when a third of the direct watershed loading was to the two highest orders compared to a uniform loading.

An intracellular signaling hierarchy determines direction of migration in opposing chemotactic gradients

Abstract: Neutrophils must follow both endogenous and bacterial chemoattractant signals out of the vasculature and through the interstitium to arrive at a site of infection. By necessity, in the setting of multiple chemoattractants, the neutrophils must prioritize, favoring end target chemoattractants (e.g., fMLP and C5a) emanating from the site of infection over intermediary endogenous chemoattractants (e.g., IL-8 and LTB4) encountered en route to sites of infection. In this study, we propose a hierarchical model of two signaling pathways mediating the decision-making process of the neutrophils, which allows end target molecules to dominate over intermediary chemoattractants. In an under agarose assay, neutrophils predominantly migrated toward end target chemoattractants via p38 MAPK, whereas intermediary chemoattractant-induced migration was phosphoinositide 3-kinase (PI3K)/Akt dependent. When faced with competing gradients of end target and intermediary chemoattractants, Akt activation was significantly reduced within neutrophils, and the cells migrated preferentially toward end target chemoattractants even at 1/1,000th that of intermediary chemoattractants. End target molecules did not require chemotactic properties, since the p38 MAPK activator, LPS, also inhibited Akt and prevented migration to intermediary chemoattractants. p38 MAPK inhibitors not only reversed this hierarchy, such that neutrophils migrated preferentially toward intermediary chemoattractants, but also allowed neutrophils to be drawn out of a local end target chemoattractant environment and toward intermediary chemoattractants unexpectedly in an exaggerated (two- to fivefold) fashion. This was entirely related to significantly increased magnitude and duration of Akt activation. Finally, end target chemoattractant responses were predominantly Mac-1 dependent, whereas nondominant chemoattractants used primarily LFA-1. These data provide support for a two pathway signaling model wherein the end target chemoattractants activate p38 MAPK, which inhibits intermediary chemoattractant-induced PI3K/Akt pathway, establishing an intracellular signaling hierarchy.

How Firms Relate to Their Markets: An Empirical Examination of Contemporary Marketing Practices

Abstract: The authors examine 308 firms in the United States and four other Western countries to understand how different types of firms relate to their markets. Comparative analysis shows that though there is some support for consumer and goods firms being more transactional and business and service firms being more relational, there are many exceptions. The results also show that firms can be grouped into those whose marketing practices are predominantly transactional, predominantly relational, or a transactional/relational hybrid. Each group constitutes approximately one-third of the sample and includes all types of firms (consumer goods, consumer services, business-to-business goods, and business-to-business services). This suggests that marketing practices are pluralistic and managerial practice has not shifted from transactional to relational approaches per se.

American options with regime switching

Abstract: A Black-Scholes market is considered in which the underlying economy, as modeled by the parameters and volatility of the processes, switches between a finite number of states The switching is modeled by a hidden Markov chain European options are priced and a Black-Scholes equation obtained The approximate valuation of American options due to Barone-Adesi and Whaley is extended to this setting

International Union of Pharmacology. XXVIII. Proteinase-Activated Receptors

Abstract: Proteinase-activated receptors (PARs) represent a unique subclass of G-protein-coupled receptors of which four family members have now been cloned from a number of species. The novel mechanism of receptor activation involves the proteolytic unmasking of a cryptic N-terminal receptor sequence that, remaining tethered, binds to and triggers receptor function. In addition, short (five to six amino acids) synthetic peptides, based on the proteolytically revealed motif, can activate PARs without the unmasking of the tethered ligand. This article summarizes the experiments leading to the pharmacological characterization and cloning of the four PAR family members and provides a rationale for their designation by the acronym “PAR”. The ability to distinguish among the PARs pharmacologically 1) with selective proteinase activators, 2) with receptor-selective peptide agonists, and 3) with peptide and nonpeptide antagonists is discussed, as are the molecular mechanisms of receptor activation and desensitization/internalization. Finally, the potential physiological roles of the PARs, which are widely distributed in many organs in the settings of tissue injury, repair, and remodeling, including embryogenesis and oncogenesis are discussed, and the newly appreciated roles of proteinases as signaling molecules that can act as either functional agonists or antagonists are highlighted.

Targeting leukocyte MMPs and transmigration: minocycline as a potential therapy for multiple sclerosis.

Abstract: Multiple sclerosis is characterized by the infiltration of leukocytes into the CNS. As matrix metalloproteinases (MMPs) facilitate the passage of leukocytes across matrix barriers, we tested the hypothesis that targeting MMPs could attenuate neuro-inflammation. We report that minocycline, a widely used generic drug with a good safety record, inhibited MMP activity, reduced production of MMP-9 and decreased the transmigration of T lymphocytes across a fibronectin matrix barrier. In addition, minocycline was efficacious against both mild and severe experimental autoimmune encephalomyelitis (EAE) in mice, an animal model of multiple sclerosis. When severe EAE was produced, minocycline pre-treatment delayed the course of the disease: when maximal disease activity occurred in vehicle-treated EAE mice, minocycline animals were relatively normal and had minimal signs of inflammation and demyelination in the CNS. When tested in mice afflicted with mild EAE, minocycline attenuated the clinical severity of disease throughout the course of treatment. These results indicate that minocycline may constitute a safe and inexpensive therapy for multiple sclerosis.

Sources of nitrate in rivers draining sixteen watersheds in the northeastern U.S.: Isotopic constraints

Abstract: The feasibility of using nitrogen and oxygen isotope ratios of nitrate (NO 3 − ) for elucidating sources and transformations of riverine nitrate was evaluated in a comparative study of 16 watersheds in the northeastern U.S.A. Stream water was sampled repeatedly at the outlets of the watersheds between January and December 1999 for determining concentrations, δ 15N values, and δ 180 values of riverine nitrate.

Medication adherence of individuals with a first episode of psychosis

Abstract: Objective: To determine rates of adherence to antipsychotic medication in first episode patients and the correlates of adherence in this group. Method: Subjects were the first 200 admissions to an Early Psychosis Program. Adherence was determined on a three-point scale. Symptoms, medication side-effects, quality of life, substance use and family involvement were examined longitudinally. Results: In their first year in the program 39% were non-adherent, 20% inadequately adherent, and 41% adherent. Non-adherent patients demonstrated more positive symptoms, more relapses, more alcohol and cannabis use, reduced insight, and poorer quality of life. They were younger, had an earlier age of onset and less likely to have a family member involved in treatment. Conclusion: Results for this group are similar to those reported in the literature. Correlates are often the consequence of non-adherence. Non-compliance has to be anticipated and relationships maintained with patients and families to intervene as soon as possible to minimize the consequence of non-compliance.

Are eyes special? It depends on how you look at it.

Abstract: Recent behavioral data have shown that central nonpredictive gaze direction triggers reflexive shifts of attention toward the gazed-at location (e.g., Friesen & Kingstone, 1998). Friesen and Kingstone suggested that this reflexive orienting effect is unique to biologically relevant stimuli. Three experiments were conducted to test this proposal by comparing the attentional orienting produced by nonpredictive gaze cues (biologically relevant) with the attentional orienting produced by nonpredictive arrow cues (biologically irrelevant). Both types of cues produced reflexive orienting in adults (Experiment 1) and preschoolers (Experiment 2), suggesting that gaze cues are not special. However, Experiment 3 showed that nonpredictive arrows produced reflexive orienting in both hemispheres of a split-brain patient. This contrasts with Kingstone, Friesen, and Gazzaniga's (2000) finding that nonpredictive gaze cues produce reflexive orienting only in the face-processing hemisphere of split-brain patients. Therefore, although nonpredictive eyes and arrows may produce similar behavioral effects, they are not subserved by the same brain systems. Together, these data provide important insight into the nature of the representations of directional stimuli involved in reflexive attentional orienting.