Showing papers by "Queen's University published in 2001"

Systematic Genetic Analysis with Ordered Arrays of Yeast Deletion Mutants

Abstract: In Saccharomyces cerevisiae, more than 80% of the ∼6200 predicted genes are nonessential, implying that the genome is buffered from the phenotypic consequences of genetic perturbation. To evaluate function, we developed a method for systematic construction of double mutants, termed synthetic genetic array (SGA) analysis, in which a query mutation is crossed to an array of ∼4700 deletion mutants. Inviable double-mutant meiotic progeny identify functional relationships between genes. SGA analysis of genes with roles in cytoskeletal organization (BNI1,ARP2, ARC40, BIM1), DNA synthesis and repair (SGS1, RAD27), or uncharacterized functions (BBC1, NBP2) generated a network of 291 interactions among 204 genes. Systematic application of this approach should produce a global map of gene function.

Measurement of the rate of ve + d → p + p + e- interactions produced by 8B solar neutrinos at the sudbury neutrino observatory

Abstract: Solar neutrinos from the decay of 8B have been detected at the Sudbury Neutrino Observatory (SNO) via the charged current (CC) reaction on deuterium and by the elastic scattering (ES) of electrons. The CC reaction is sensitive exclusively to νe, while the ES reaction also has a small sensitivity to νμ and ντ. The flux of νe from 8B decay measured by the CC reaction rate is φCC(ν e )=[1.75±0.07(stat.) −0.11 +0.12 (syst.)×0.05(theor.)]×106cm−2s−1. Assuming no flavor transformation, the flux inferred from the ES reaction rate is φES(ν x )=[2.39±0.34(stat.) −0.14 +0.16 (syst.)]×106cm−2s−1. Comparison of φCC(νe) to the Super-Kamiokande collaboration’s precision value of φES(νx) yields a 3.3σ difference, assuming the systematic uncertainties are normally distributed, providing evidence that there is a nonelectron flavor active neutrino component in the solar flux. The total flux of active 8B neutrinos is thus determined to be (5.44±0.99)×106 cm−2 s−1, in close agreement with the predictions of solar models.

A Psychology of Immigration

Abstract: The discipline of psychology has much to contribute to our understanding of immigrants and the process of immigration A framework is proposed that lays out two complementary domains of psychological research, both rooted in contextual factors, and both leading to policy and program development The first (acculturation) stems from research in anthropology and is now a central part of cross- cultural psychology; the second (intergroup relations) stems from sociology and is now a core feature of social psychology Both domains are concerned with two fundamental issues that face immigrants and the society of settlement: maintenance of group characteristics and contact between groups The intersection of these issues creates an intercultural space, within which members of both groups develop their cultural boundaries and social relationships A case is made for the benefits of integration as a strategy for immigrants and for multiculturalism as a policy for the larger society The articles in this issue are then discussed in relation to these conceptual frameworks and empirical findings

Alignment Between Business and IS Strategies: A Study of Prospectors, Analyzers, and Defenders

Abstract: Alignment between business strategy and IS strategy is widely believed to improve business performance. This paper examines the impact of alignment on perceived business performance using Miles and Snow's popular classification of Defender, Analyzer, and Prospector business strategies. A priori theoretical profiles for these business strategies are developed using Venkatraman's (1989a) measure of business strategy. Theoretical profiles for IS strategies are developed in terms of four types of systems--operational support systems, market information systems, strategic decision-support systems, and interorganizational systems. Empirical data from two multirespondent surveys of 164 and 62 companies, respectively, are analyzed. Results indicate that alignment affects perceived business performance but only insome organizations. Alignment seems to influence overall business success in Prospectors and Analyzers but not in Defenders. Implications for future research and practice are discussed.

Dynamic Hyperinflation and Exercise Intolerance in Chronic Obstructive Pulmonary Disease

Abstract: The role of dynamic hyperinflation (DH) in exercise limitation in chronic obstructive pulmonary disease (COPD) remains to be de- fined. We examined DH during exercise in 105 patients with COPD (FEV 1 � 37 � 13% predicted; meanSD) and studied the rela- tionships between resting lung volumes, DH during exercise, and peak oxygen consumption ( O 2 ). Patients completed pulmonary function tests and incremental cycle exercise tests. We measured the change in inspiratory capacity ( ∆ IC) during exercise to reflect changes in DH. During exercise, 80% of patients showed signifi- cant DH above resting values. IC decreased 0.37 � 0.39 L or 14 � 15% predicted during exercise (p � 0.0005), but with large varia- tion in range. ∆ IC correlated best with resting IC, both expressed %predicted (r � � 0.50, p � 0.0005). Peak O 2 (%predicted maxi- mum) correlated best with the peak tidal volume attained (V T standardized as % of predicted vital capacity) (r � 0.68, p � 0.0005), which, in turn, correlated strongly with IC at peak exer- cise (r � 0.79, p � 0.0005) or at rest (r � 0.75, p � 0.0005). The extent of DH during exercise in COPD correlated best with resting IC. DH curtailed the V T response to exercise. This inability to ex- pand V T in response to increasing metabolic demand contributed importantly to exercise intolerance in COPD. Chronic obstructive pulmonary disease (COPD) is a heteroge- neous disorder characterized by dysfunction of the small and large airways, as well as destruction of the lung parenchyma and its vasculature in highly variable combinations. The pathophysiological hallmark of COPD is expiratory flow limi- tation, which, in more advanced disease, occurs even during resting quiet breathing. As a consequence, resting lung vol- ume (functional residual capacity (FRC)) is dynamically, and not statically, determined. During exercise, as ventilatory de- mands increase in flow-limited patients, progressive air trap- ping and further dynamic lung hyperinflation (DH) above al- ready increased resting values is inevitable (1, 2). Recent studies have shown that DH during exercise contributes to perceived respiratory discomfort (3, 4). Indirect evidence of the importance of DH comes from studies that have demon- strated that alleviation of dyspnea following bronchodilator therapy and lung volume reduction surgery (LVRS) was ex- plained, in part, by reduced operating lung volumes (5, 6). However, it is not clear from previous studies to what extent the behavior of operating lung volumes during exercise influ- ences peak exercise capacity in COPD. Moreover, earlier studies have shown wide variability in the extent of DH with V ·

A pooled analysis of adjuvant chemotherapy for resected colon cancer in elderly patients.

Abstract: Background Adjuvant chemotherapy is standard treatment for patients with resected colon cancer who are at high risk for recurrence, but the efficacy and toxicity of such treatment in patients more than 70 years of age are controversial Methods We performed a pooled analysis, based on the intention to treat, of individual patient data from seven phase 3 randomized trials (involving 3351 patients) in which the effects of postoperative fluorouracil plus leucovorin (five trials) or fluorouracil plus levamisole (two trials) were compared with the effects of surgery alone in patients with stage II or III colon cancer The patients were grouped into four age categories of equal size, and analyses were repeated with 10-year age ranges (≤50, 51 to 60, 61 to 70, and >70 years), with the same conclusions The toxic effects measured in all trials were nausea or vomiting, diarrhea, stomatitis, and leukopenia Patients in the fluorouracil-plus-leucovorin and fluorouracil-plus-levamisole groups were combined for the ef

Review: Current international research into cellulosic fibres and composites

Abstract: The following paper summarises a number of international research projects being undertaken to understand the mechanical properties of natural cellulose fibres and composite materials. In particular the use of novel techniques, such as Raman spectroscopy, synchrotron x-ray and half-fringe photoelastic methods of measuring the physical and micromechanical properties of cellulose fibres is reported. Current single fibre testing procedures are also reviewed with emphasis on the end-use in papermaking. The techniques involved in chemically modifying fibres to improve interfacial adhesion in composites are also reviewed, and the use of novel fibre sources such as bacterial and animal cellulose. It is found that there is overlap in current international research into this area, and that there are complementary approaches and therefore further combining of these may make further progress possible. In particular a need to measure locally the adhesion properties and deformation processes of fibres in composites, with different chemical treatments, ought to be a focus of future research.

Eye–Hand Coordination in Object Manipulation

Abstract: We analyzed the coordination between gaze behavior, fingertip movements, and movements of the manipulated object when subjects reached for and grasped a bar and moved it to press a target-switch. Subjects almost exclusively fixated certain landmarks critical for the control of the task. Landmarks at which contact events took place were obligatory gaze targets. These included the grasp site on the bar, the target, and the support surface where the bar was returned after target contact. Any obstacle in the direct movement path and the tip of the bar were optional landmarks. Subjects never fixated the hand or the moving bar. Gaze and hand/bar movements were linked concerning landmarks, with gaze leading. The instant that gaze exited a given landmark coincided with a kinematic event at that landmark in a manner suggesting that subjects monitored critical kinematic events for phasic verification of task progress and subgoal completion. For both the obstacle and target, subjects directed saccades and fixations to sites that were offset from the physical extension of the objects. Fixations related to an obstacle appeared to specify a location around which the extending tip of the bar should travel. We conclude that gaze supports hand movement planning by marking key positions to which the fingertips or grasped object are subsequently directed. The salience of gaze targets arises from the functional sensorimotor requirements of the task. We further suggest that gaze control contributes to the development and maintenance of sensorimotor correlation matrices that support predictive motor control in manipulation.

Social disclosure, financial disclosure and the cost of equity capital

Abstract: We test the relation between financial and social disclosure and the cost of equity capital for a sample of Canadian firms with year-ends in 1990, 1991 and 1992. We find that, consistent with prior research, the quantity and quality of financial disclosure is negatively related to the cost of equity capital for firms with low analyst following. Contrary to expectations, there is a significant positive relation between social disclosures and the cost of equity capital. This positive relationship is mitigated among firms with better financial performance. We consider some biases in social disclosures that may explain this result. We also note that social disclosures may benefit the firm through its effect on organizational stakeholders other than equity investors.

A Mind So Rare: The Evolution of Human Consciousness

Abstract: In this masterful rebuttal to the prevailing neuroscientific arguments that seek to explain away consciousness, Merlin Donald presents "a sophisticated conception of a multilayered consciousness drawing much of its power from its cultural matrix" (Booklist). Donald makes "a persuasive case...for consciousness as the central player in the drama of mind" (Peter Dodwell), as he details the forces, both cultural and neuronal, that power our distinctively human modes of awareness. He proposes that the human mind is a hybrid product, interweaving a super-complex form of matter (the brain) with an invisible symbolic web (culture) to form a "distributed" cognitive network. This hybrid mind, he argues, is our main evolutionary advantage, for it allowed humanity as a species to break free of the limitations of the mammalian brain. "Donald transcends the simplistic claims of Evolutionary Psychology,...offering a true Darwinian perspective on the evolution of consciousness."-Philip Lieberman

Habitat Selection Studies in Avian Ecology: A Critical Review

Abstract: The study of habitat use and selection in birds has a long tradition (Grinnell 1917, Kendeigh 1945, Svardson 1949, Hild6n 1965; Block and Brennan 1993). Early habitat-selection theory was characterized by correlative models of habitat characteristics and species abundance (MacArthur and Pianka 1966, Verner et al. 1986, Rosenzweig 1991), which subsequently evolved into models that involved density dependence: the "ideal-free distribution" and "ideal-despotic distribution" models (Fretwell and Lucas 1970, Fretwell 1972). More recently, habitat-selection studies have shown that many factors, such as landscape structure, can influence exactly how "ideal" and "free" animals are while moving through a landscape and selecting habitats (Karr and Freemark 1983, Pulliam and Danielson 1991, Petit and Petit 1996). Habitat-selection studies have recently assumed a new urgency, partially as a result of the importance of incorporating both habitat and demographic information into conservation planning (Caughley 1994). Nevertheless, ornithologists tend to be inconsistent in their conceptual framework and terminology with regard to (1) what constitutes habitat use versus selection, (2) the behavioral and evolutionary context of their findings, and (3) the order or scale of their study, from microhabitat to geographic range (Johnson 1980, Orians and Wittenberger 1991). The purpose of this review is to address those concerns through a survey of recent literature and highlight areas where improvements or advances can be made in avian habitat ecology. Three Areas of Concern.-Definitions.-The semantic and empirical distinctions between the terms habitat use and habitat selection are often unclear (Hall et al. 1997). Habitat refers to a distinctive set of physical environmental factors that a species uses for its survival and reproduction (Block and Brennan 1993). Habitat use refers to the way in which an individual or species uses habitats to meet its life history needs (Block and Brennan 1993). The study of habitat-use patterns describes the actual distribution of individuals across habitat types (Hutto 1985). Habitat selection refers to a hierarchical process of behavioral re-

Naturalistic Observations of Peer Interventions in Bullying

Abstract: This study examined peer intervention in bullying using naturalistic observations on school playgrounds. The sample comprised 58 children (37 boys and 21 girls) in Grades 1 to 6 who were observed to intervene in bullying. Peers were present during 88% of bullying episodes and intervened in 19%. In 47% of the episodes, peers intervened aggressively. Interventions directed toward the bully were more likely to be aggressive, whereas interventions directed toward the victim or the bully-victim dyad were more likely to be nonaggressive. The majority (57%) of interventions were effective in stopping bullying. Boys were more likely to intervene when the bully and victim were male and girls when the bully and victim were female. The implications for anti-bullying interventions are discussed.

Severely reduced sexual reproduction in northern populations of a clonal plant, Decodonverticillatus (Lythraceae)

Abstract: Summary 1 In flowering plants the balance between sexual and clonal, asexual reproduction can vary widely. We quantified variation in sexual reproduction in a tristylous, clonal, aquatic plant, Decodon verticillatus , and investigated the role of ecological and genetic factors in causing this variation. 2 We surveyed components of sexual fertility and vegetative growth in 28 populations distributed along a 500-km latitudinal transect in New England, USA. Northerly populations tend to be monomorphic (M) for style length, and probably therefore have reduced sexual reproduction compared with southerly, trimorphic (T) populations. 3 Compared with T populations ( n = 10), M populations ( n = 18) exhibited large reductions for all components of sexual reproduction, including flower production, pollen deposition, pollen tube growth, fertilization, fruit set and seeds per fruit. Seven M populations produced no seed at all, and the other 11 very little (mean = 24 vs. 1139 seeds per plant in trimorphic populations). Clonal propagation was also greatly reduced in M populations. 4 A survey of three polymorphic allozyme loci detected only single, usually heterozygous, genotypes in 15 M populations, whereas all T populations were genotypically diverse. The other three M populations contained three or fewer genotypes and one always predominated. Sexual recruitment is therefore extremely rare. 5 Comparison of the sexual fertility of M and T populations in a concurrent common glasshouse experiment with our field data revealed that reduced sexual performance in northern M populations is principally due to genetic factors, but is also caused by ecological factors that covary with latitude. 6 This abrupt shift away from sexual reproduction in populations at the northern periphery of the geographical range in D . verticillatus may greatly limit their evolutionary potential and restrict further northward expansion.

The retinoic acid-metabolizing enzyme, CYP26A1, is essential for normal hindbrain patterning, vertebral identity, and development of posterior structures

Abstract: The active derivative of vitamin A, retinoic acid (RA), is essential for normal embryonic development. The spatio-temporal distribution of embryonic RA results from regulated expression of RA-synthesizing retinaldehyde dehydrogenases and RA-metabolizing cytochrome P450s (CYP26). Excess RA administration or RA deficiency results in a complex spectrum of embryonic abnormalities. As a first step in understanding the developmental function of RA-metabolizing enzymes, we have disrupted the murine Cyp26A1 gene. We report that Cyp26A1-null mutants die during mid-late gestation and show a number of major morphogenetic defects. Spina bifida and truncation of the tail and lumbosacral region (including abnormalities of the kidneys, urogenital tract, and hindgut) are the most conspicuous defects, leading in extreme cases to a sirenomelia (“mermaid tail”) phenotype. Cyp26A1 mutants also show posterior transformations of cervical vertebrae and abnormal patterning of the rostral hindbrain, which appears to be partially posteriorly transformed. These defects correlate with two major sites of Cyp26A1 expression in the rostral neural plate and embryonic tail bud. Because all of the Cyp26A1−/− abnormalities closely resemble RA teratogenic effects, we postulate that the key function of CYP26A1 is to maintain specific embryonic areas in a RA-depleted state, to protect them against the deleterious effect of ectopic RA signaling.

Exploring Perceptions of Organizational Ownership of Information and Expertise

Abstract: Beliefs of organizational ownership relate to whether information and knowledge created by an individual knowledge worker are believed to be owned by the organization. Beliefs about property rights affect information and knowledge sharing. This study explored factors that help determine an individual's beliefs about the organizational ownership of information and expertise that he or she has created. Four different situations of organizational ownership (information vs. expertise/internal vs. external sharing) were considered. The study found that a belief in self-ownership was positively associated with organizational ownership - suggesting a collaborative type of ownership situation for both information and expertise and for both internal (intraorganizational) and external (interorganizational) sharing situations. Organizational culture and the type of employee also influenced the beliefs of organizational ownership in all four scenarios. We conclude the paper with implications for practice and future research.

Effect of meal viscosity and nutrients on satiety, intragastric dilution, and emptying assessed by MRI

Abstract: The relationship between the intragastric distribution, dilution, and emptying of meals and satiety was studied using noninvasive magnetic resonance imaging techniques in 12 healthy subjects with f...

Multidrug efflux pumps and antimicrobial resistance in Pseudomonas aeruginosa and related organisms.

Abstract: Pseudomonas aeruginosa is an opportunistic human pathogen characterized by an innate resistance to multiple antimicrobial agents. A major contribution to this intrinsic multidrug resistance is provided by a number of broadly-specific multidrug efflux systems, including MexAB-OprM and MexXY-OprM. In addition, these and two additional tripartite efflux systems, MexCD-OprJ and MexEF-OprN, promote acquired multidrug resistance as a result of mutational hyperexpression of the efflux genes. In addition to antibiotics, these pumps promote export of numerous dyes, detergents, inhibitors, disinfectants, organic solvents and homoserine lactones involved in quorum sensing. The efflux pump proteins are highly homologous and consist of a cytoplasmic membraneassociated drug-proton antiporter of the ResistanceNodulation-Division (RND) family, an outer membrane channel-forming protein [sometimes called outer membrane factor (OMF)] and a periplasmic membrane fusion protein (MFP). Homologues of these systems have been described in Stenotrophomonas maltophilia, Burkholderia cepacia, Burkholderia pseudomallei and the non-pathogen Pseudomonas putida, where they play a role in export of and resistance to multiple antimicrobial agents and/or organic solvents. Although the natural function of these multidrug efflux systems is largely unknown, their contribution to antibiotic resistance and their conservation in a number of important human pathogens makes them logical targets for therapeutic intervention.

University-to-industry knowledge transfer: literature review and unanswered questions

Abstract: This paper reviews the economic literature concerning university-to-industry knowledge transfer. Papers on this topic are divided into four categories. Research in the ‘firm characteristics’ category focuses directly on company issues, such as internal organization, resource allocation, and partnerships. In contrast, research in the ‘university characteristics’ stream pays little attention to the firms that commercialize inventions, but rather focuses on issues relating to the university, such as licensing strategies, incentives for professors to patent, and policies such as taking equity in return for intellectual property. The ‘geography in terms of localized spillovers’ stream of research considers the spatial relationship between firms and universities relative to performance in terms of knowledge transfer success. Finally, the ‘channels of knowledge transfer‘ literature examines the relative importance of various transfer pathways between universities and firms, such as publications, patents, and consulting. Each of these research streams is discussed and key papers are described highlighting important methodologies and results. Finally, an outline of topics requiring further research in each of the four categories is offered.

A Model of Saccade Initiation Based on the Competitive Integration of Exogenous and Endogenous Signals in the Superior Colliculus

Abstract: Significant advances in cognitive neuroscience can be achieved by combining techniques used to measure behavior and brain activity with neural modeling. Here we apply this approach to the initiation of rapid eye movements (saccades), which are used to redirect the visual axis to targets of interest. It is well known that the superior colliculus (SC) in the midbrain plays a major role in generating saccadic eye movements, and physiological studies have provided important knowledge of the activity pattern of neurons in this structure. Based on the observation that the SC receives localized sensory (exogenous) and voluntary (endogenous) inputs, our model assumes that this information is integrated by dynamic competition across local collicular interactions. The model accounts well for the effects upon saccadic reaction time (SRT) due to removal of fixation, the presence of distractors, execution of pro- versus antisaccades, and variation in target probability, and suggests a possible mechanism for the generation of express saccades. In each of these cases, the activity patterns of "neurons" within the model closely resemble actual cell behavior in the intermediate layer of the SC. The interaction structure we employ is instrumental for producing a physiologically faithful model and results in new insights and hypotheses regarding the neural mechanisms underlying saccade initiation.

Eye movement desensitization and reprocessing (EMDR): a meta-analysis.

Abstract: Eye movement desensitization and reprocessing (EMDR), a controversial treatment suggested for posttraumatic stress disorder (PTSD) and other conditions, was evaluated in a meta-analysis of 34 studies that examined EMDR with a variety of populations and measures. Process and outcome measures were examined separately. and EMDR showed an effect on both when compared with no treatment and with therapies not using exposure to anxiety-provoking stimuli and in pre post EMDR comparisons. However, no significant effect was found when EMDR was compared with other exposure techniques. No incremental effect of eye movements was noted when EMDR was compared with the same procedure without them. R. J. DeRubeis and P. Crits-Christoph (1998) noted that EMDR is a potentially effective treatment for noncombat PTSD. but studies that examined such patient groups did not give clear support to this. In sum, EMDR appears to be no more effective than other exposure techniques, and evidence suggests that the eye movements integral to the treatment, and to its name, are unnecessary.

Calmodulin as a versatile calcium signal transducer in plants.

Abstract: The complexity of Ca2+ patterns observed in eukaryotic cells, including plants, has led to the hypothesis that specific patterns of Ca2+ propagation, termed Ca2+ signatures, encode information and relay it to downstream elements (effectors) for translation into appropriate cellular responses. Ca2+ -binding proteins (sensors) play a key role in decoding Ca2+ signatures and transducing signals by activating specific targets and pathways. Calmodulin is a Ca2+ sensor known to modulate the activity of many mammalian proteins, whose targets in plants are now being actively characterized. Plants possess an interesting and rapidly growing list of calmodulin targets with a variety of cellular roles. Nevertheless, many targets appear to be unique to plants and remain uncharacterized, calling for a concerted effort to elucidate their functions. Moreover, the extended family of calmodulin-related proteins in plants consists of evolutionarily divergent members, mostly of unknown function, although some have recently been implicated in stress responses. It is hoped that advances in functional genomics, and the research tools it generates, will help to explain themultiplicity of calmodulin genes in plants, and to identify their downstream effectors. This review summarizes current knowledge of the Ca2+ -calmodulin messenger system in plants and presents suggestions for future areas of research. Contents I. Introduction 36 II. CaM isoforms and CaM-like proteins 37 III. CaM-target proteins 42 IV. CaM and nuclear functions 46 V. Regulation of ion transport 49 VI. CaM and plant responses to environmental stimuli 52 VII. Conclusions and future studies 58 Acknowledgements 59 References 59.