Showing papers by "York University published in 2001"

Chains and networks, territories and scales: towards a relational framework for analysing the global economy

Abstract: A vast and continually expanding literature on economic globalization continues to generate a miasma of conflicting viewpoints and alternative discourses. This article argues that any understanding of the global economy must be sensitive to four considerations: (a) conceptual categories and labels carry with them the dis- cursive power to shape material processes; (b) multiple scales of analysis must be incorporated in recognition of the contemporary 'relativization of scale'; (c) no single institutional or organizational locus of analysis should be privileged; and (d) extrapolations from specific case studies and instances must be treated with caution, but this should not preclude the option of discussing the global economy, and power relations within it, as a structural whole. This paper advocates a network method- ology as a potential framework to incorporate these concerns. Such a methodology requires us to identify actors in networks, their ongoing relations and the structural outcomes of these relations. Networks thus become the foundational unit of analysis for our understanding of the global economy, rather than individuals, firms or nation states. In presenting this argument we critically examine two examples of network methodology that have been used to provide frameworks for analysing the global economy: global commodity chains and actor-network theory. We suggest that while they fall short of fulfilling the promise of a network methodology in some respects, they do provide indications of the utility of such a methodology as a basis for under- standing the global economy.

Invited Review: contractile activity-induced mitochondrial biogenesis in skeletal muscle.

Abstract: Chronic contractile activity produces mitochondrial biogenesis in muscle. This adaptation results in a significant shift in adenine nucleotide metabolism, with attendant improvements in fatigue res...

Plasticity in Skeletal, Cardiac, and Smooth Muscle Invited Review: Contractile activity-induced mitochondrial biogenesis in skeletal muscle

Abstract: Hood, David A Invited Review: Contractile activity-induced mitochondrial biogenesis in skeletal muscle J Appl Physiol 90: 1137–1157, 2001—Chronic contractile activity produces mitochondrial biogenesis in muscle This adaptation results in a significant shift in adenine nucleotide metabolism, with attendant improvements in fatigue resistance The vast majority of mitochondrial proteins are derived from the nuclear genome, necessitating the transcription of genes, the translation of mRNA into protein, the targeting of the protein to a mitochondrial compartment via the import machinery, and the assembly of multisubunit enzyme complexes in the respiratory chain or matrix Putative signals involved in initiating this pathway of gene expression in response to contractile activity likely arise from combinations of accelerations in ATP turnover or imbalances between mitochondrial ATP synthesis and cellular ATP demand, and Ca fluxes These rapid events are followed by the activation of exercise-responsive kinases, which phosphorylate proteins such as transcription factors, which subsequently bind to upstream regulatory regions in DNA, to alter transcription rates Contractile activity increases the mRNA levels of nuclearencoded proteins such as cytochrome c and mitochondrial transcription factor A (Tfam) and mRNA levels of upstream transcription factors like c-jun and nuclear respiratory factor-1 (NRF-1) mRNA level changes are often most evident during the postexercise recovery period, and they can occur as a result of contractile activity-induced increases in transcription or mRNA stability Tfam is imported into mitochondria and controls the expression of mitochondrial DNA (mtDNA) mtDNA contributes only 13 protein products to the respiratory chain, but they are vital for electron transport and ATP synthesis Contractile activity increases Tfam expression and accelerates its import into mitochondria, resulting in increased mtDNA transcription and replication The result of this coordinated expression of the nuclear and the mitochondrial genomes, along with poorly understood changes in phospholipid synthesis, is an expansion of the muscle mitochondrial reticulum Further understanding of 1) regulation of mtDNA expression, 2) upstream activators of NRF-1 and other transcription factors, 3) the identity of mRNA stabilizing proteins, and 4) potential of contractile activity-induced changes in apoptotic signals are warranted

Arousal, Mood, and The Mozart Effect:

Abstract: The "Mozart effect" refers to claims that people perform better on tests of spatial abilities after listening to music composed by Mozart. We examined whether the Mozart effect is a consequence of between-condition differences in arousal and mood. Participants com- pleted a test of spatial abilities after listening to music or sitting in si- lence. The music was a Mozart sonata (a pleasant and energetic piece) for some participants and an Albinoni adagio (a slow, sad piece) for others. We also measured enjoyment, arousal, and mood. Performance on the spatial task was better following the music than the silence condition, but only for participants who heard Mozart. The two music selections also induced differential responding on the en- joyment, arousal, and mood measures. Moreover, when such differ- ences were held constant by statistical means, the Mozart effect disappeared. These findings provide compelling evidence that the Mozart effect is an artifact of arousal and mood.

Scaling-up and model inversion methods with narrowband optical indices for chlorophyll content estimation in closed forest canopies with hyperspectral data

Abstract: Radiative transfer theory and modeling assumptions were applied at laboratory and field scales in order to study the link between leaf reflectance and transmittance and canopy hyper-spectral data for chlorophyll content estimation. This study was focused on 12 sites of Acer saccharum M. (sugar maple) in the Algoma Region, Canada, where field measurements, laboratory-simulation experiments, and hyper-spectral compact airborne spectrographic imager (CASI) imagery of 72 channels in the visible and near-infrared region and up to 1-m spatial resolution data were acquired in the 1997, 1998, and 1999 campaigns. A different set of 14 sites of the same species were used in 2000 for validation of methodologies. Infinite reflectance and canopy reflectance models were used to link leaf to canopy levels through radiative transfer simulation. The closed and dense (LAI>4) forest canopies of Acer saccharum M. used for this study, and the high spatial resolution reflectance data targeting crowns, allowed the use of optically thick simulation formulae and turbid-medium SAILH and MCRM canopy reflectance models for chlorophyll content estimation by scaling-up and by numerical model inversion approaches through coupling to the PROSPECT leaf radiative transfer model. Study of the merit function in the numerical inversion showed that red edge optical indices used in the minimizing function such as R/sub 750//R/sub 710/ perform better than when all single spectral reflectance channels from hyper-spectral airborne CASI data are used, and in addition, the effect of shadows and LAI variation are minimized.

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.

Decolonizing methodologies: research and indigenous people.

Abstract: but have felt out of place in organizations that are designed for and run by middle class white men. The women Campbell has worked with have often had the same experience, being unable to discuss their illness with partners or other members of their community and finding a dearth of accessible support organizations. Gender, class and ethnicity interact in the impact that HIV/AIDS has on individuals. Campbell shies away from the implication of her study, which is that there is a hierarchy of suffering, gay men being the disease’s most prominent victims but also the best supported. Yet it seems clear that there is such a hierarchy. Researchers should not be ashamed of naming it. The spread and impact of the disease reflects – though by no means perfectly – the differential access to resources, power and control of different groups in different parts of the world. Campbell has produced a moving work, drawing on extensive research: it certainly should be read by those in government who are meant to be formulating policies to combat HIV/AIDS and poverty. The message is that, without strong action at international, national and community levels, social exclusion and the virus combine to produce a tragic outcome for vulnerable men, women and children.

The Life-Cycle Model of Consumption and Saving

Abstract: A central implication of life-cycle models is that agents smooth consumption We review the empirical evidence on smoothing at frequencies from within the year up to across a lifetime We find that life-cycle models--particular those which incorporate realistic features of markets and goods--have more empirical successes than failures We also show that some apparent deviations from theoretical predictions imply very small welfare losses for agents Finally, we emphasize that the coherence of life-cycle models imposes an important discipline when incorporating new features into models

Compensatory conviction in the face of personal uncertainty: going to extremes and being oneself.

Abstract: Study 1 participants' self-integrity (C. M. Steele. 1988) was threatened by deliberative mind-set (S. E. Taylor & P. M. Gollwitzer, 1995) induced uncertainty. They masked the uncertainty with more extreme conviction about social issues. An integrity-repair exercise after the threat, however, eliminated uncertainty and the conviction response. In Study 2, the same threat caused clarified values and more self-consistent personal goals. Two other uncertainty-related threats, mortality salience and temporal discontinuity, caused similar responses: more extreme intergroup bias in Study 3, and more self-consistent personal goals and identifications in Study 4. Going to extremes and being oneself are seen as 2 modes of compensatory conviction used to defend against personal uncertainty. Relevance to cognitive dissonance and authoritarianism theories is discussed, and a new perspective on terror managenment theory (J. Greenberg, S. Solomom, & T. Pyszczynski, 1997) is proposed.

Introduction to special issue on burnout and health

Abstract: In recent years, the issue of occupational stress and burnout have received increasing research attention. Given the amount of time people spend on work-related activities and the central importance of work to one's sense of identity and self-worth, it is not surprising that occupational stress is regarded as a central area of study. Although burnout is linked to the extensive literature on occupational health, burnout goes beyond occupational health by focusing on specific stressors in the workplace to emphasize total life and environmental pressures affecting health.

Accuracy measures for evaluating computer pointing devices

Abstract: In view of the difficulties in evaluating computer pointing devices across different tasks within dynamic and complex systems, new performance measures are needed. This paper proposes seven new accuracy measures to elicit (sometimes subtle) differences among devices in precision pointing tasks. The measures are target re-entry, task axis crossing, movement direction change, orthogonal direction change, movement variability, movement error, and movement offset. Unlike movement time, error rate, and throughput, which are based on a single measurement per trial, the new measures capture aspects of movement behaviour during a trial. The theoretical basis and computational techniques for the measures are described, with examples given. An evaluation with four pointing devices was conducted to validate the measures. A causal relationship to pointing device efficiency (viz. throughput) was found, as was an ability to discriminate among devices in situations where differences did not otherwise appear. Implications for pointing device research are discussed.

The functional anatomy of humor: segregating cognitive and affective components

Abstract: Humor, a unique human characteristic, is critical in thought, communication and social interaction Successful jokes involve a cognitive juxtaposition of mental sets, followed by an affective feeling of amusement; we isolated these two components of humor by using event-related fMRI on subjects who listened to auditorily presented semantic and phonological jokes (puns) and indicated whether or not they found the items amusing Our findings suggest that whereas there are modality-specific pathways for processing the juxtaposition of mental sets necessary for the appreciation of jokes, a common component of humor is expressed in activity in medial ventral prefrontal cortex, a region involved in reward processing

Emotion and Ethical Decision-Making in Organizations

Abstract: While the influence of emotion on individuals' ethical decisions has been identified by numerous researchers, little is known about how emotions influence individuals' ethical decision process. Thus, it is not clear whether different emotions promote and/or discourage ethical decision-making in the workplace. To address this gap, this paper develops a model that illustrates how emotion affects the components of individuals' ethical decision-making process. The model is developed by integrating research findings that consider the two dimensions of emotion, arousal and feeling state, into an applied cognitive-developmental perspective on the process of ethical decision-making. The model demonstrates that certain emotional states influence the individual's propensity to identify ethical dilemmas, facilitate the formation of the individual's prescriptive judgments at sophisticated levels of moral development, lead to ethical decision choices that are consistent with the individual's prescriptive judgements, and promote the individual's compliance with his or her ethical decision choices. In particular, the model suggests that individuals experiencing arousal and positive affect resolve ethical dilemmas in a manner consistent with more sophisticated cognitive moral structures. Implications for theory and practice are discussed.

A reaction–diffusion model for a single species with age structure. I Travelling wavefronts on unbounded domains

Abstract: In this paper, we derive the equation for a single species population with two age classes and a fixed maturation period living in a spatially unbounded environment. We show that if the mature deat...

Mortality derivatives and the option to annuitise

Abstract: Most US-based insurance companies offer holders of their tax-sheltered savings plans (VAs), the long-term option to annuitise their policy at a pre-determined rate over a pre-specified period of time. Currently, there is approximately one trillion dollars invested in such policies, with guaranteed annuitisation rates, in addition to any guaranteed minimum death benefit. The insurance company has essentially granted the policyholder an option on two underlying stochastic variables; future interest rates and future mortality rates. Although the (put) option on interest rates is obvious, the (put) option on mortality rates is not. Motivated by this product, this paper attempts to value (options on) mortality-contingent claims, by stochastically modelling the future hazard-plus-interest rate. Heuristically, we treat the underlying life annuity as a defaultable coupon-bearing bond, where the default occurs at the exogenous time of death. From an actuarial perspective, rather than considering the force of mortality (hazard rate) at time t for a person now age x , as a number μ x ( t ), we view it as a random variable forward rate μ ˜ x ( t ) , whose expectation is the force of mortality in the classical sense ( μ x ( t ) = E [ μ ˜ x ( t ) ] ). Our main qualitative observation is that both mortality and interest rate risk can be hedged, and the option to annuitise can be priced by locating a replicating portfolio involving insurance, annuities and default-free bonds. We provide both a discrete and continuous-time pricing framework.

The end of the corporate environmental report? Or the advent of cybernetic sustainability reporting and communication

Abstract: It is becoming clear that communicating effectively with stakeholders on progress towards economic prosperity, environmental quality and social justice i.e. the triple bottom line, will become a defining characteristic of corporate responsibility in the 21st century (Elkington J. 1998. Cannibals with Forks: the Triple Bottom Line of 21st Century Business. New Society: Vancouver). However, most companies that currently use paper-based and even web-based communication vehicles for their corporate performance reports are not realizing the full potential value of these communications – either for themselves or for their stakeholders. This may be due in part to the fact that historically reports have not sufficiently engaged ‘direct stakeholders’, i.e. employees, customers, investors, suppliers and local communities. In this paper we review the recent history of environmental and social reporting and conclude that, whilst much progress has been made, significant challenges remain. Most notably these challenges include (i) the avoidance of engagement fatigue by stakeholders and opinion formers alike and (ii) the extension of triple-bottom-line principles from corporate headquarters into business unit operations. Conversely there is enormous potential for addressing these challenges and creating significant value for both corporations and their stakeholders through the development of truly interactive (cybernetic) corporate sustainability reports and communications delivered via the internet and other channels. We explore some of the implications of what we believe to be an inevitable transition in how these communications will be orchestrated. Copyright © 2001 John Wiley & Sons, Ltd and ERP Environment

Dynamics of travelling waves in visual perception

Abstract: Nonlinear wave propagation is ubiquitous in nature, appearing in chemical reaction kinetics1, cardiac tissue dynamics1,2, cortical spreading depression3 and slow wave sleep4. The application of dynamical modelling has provided valuable insights into the mechanisms underlying such nonlinear wave phenomena in several domains1,2,5,6. Wave propagation can also be perceived as sweeping waves of visibility that occur when the two eyes view radically different stimuli. Termed binocular rivalry, these fluctuating states of perceptual dominance and suppression are thought to provide a window into the neural dynamics that underlie conscious visual awareness7,8. Here we introduce a technique to measure the speed of rivalry dominance waves propagating around a large, essentially one-dimensional annulus. When mapped onto visual cortex, propagation speed is independent of eccentricity. Propagation speed doubles when waves travel along continuous contours, thus demonstrating effects of collinear facilitation. A neural model with reciprocal inhibition between two layers of units provides a quantitative explanation of dominance wave propagation in terms of disinhibition. Dominance waves provide a new tool for investigating fundamental cortical dynamics.

Workload and burnout in nurses

Abstract: This paper examines the relationship between workload, burnout and somatization in nurses. The respondents consisted of 1363 nurses employed in hospitals, which were undergoing extensive restructuring. Results of structural equation analyses showed that workload was positively related to emotional exhaustion. Emotional exhaustion led to cynicism and somatization, and cynicism was negatively related to nurses' professional efficacy. Implications of the results for nursing practice are discussed. Copyright © 2001 John Wiley & Sons, Ltd.

LetterWise: prefix-based disambiguation for mobile text input

Abstract: A new technique to enter text using a mobile phone keypad is described. For text input, the traditional touchtone phone keypad is ambiguous because each key encodes three or four letters. Instead of using a stored dictionary to guess the intended word, our technique uses probabilities of letter sequences --- "prefixes" --- to guess the intended letter. Compared to dictionary-based methods, this technique, called LetterWise, takes significantly less memory and allows entry of non-dictionary words without switching to a special input mode. We conducted a longitudinal study to compare LetterWise to Multitap, the conventional text entry method for mobile phones. The experiment included 20 participants (10 LetterWise, 10 Multitap), and each entered phrases of text for 20 sessions of about 30 minutes each. Error rates were similar between the techniques; however, by the end of the experiment the mean entry speed was 36% faster with LetterWise than with Multitap.

Innovation and Risk-Taking in a Transitional Economy: A Comparative Study of Chinese Managers and Entrepreneurs

Abstract: This research was set in the People’s Republic of China. As former socialist China moves from central planning toward a more market-driven economy, improved knowledge about the new environment and firm decisions within such an environment has significant implications. For organizational researchers, such a transition represents a genuine shift of paradigm, and thus offers a unique opportunity to test existing organizational theories and develop new ones. For multinational businesses seeking business opportunities, they have to compete or cooperate with these Chinese firms, whether state-owned or privately owned. Motivated by a deep curiosity in, using the language of Williamson (1996), “What is going on there” behind the “bamboo curtain,” and underpinned by a strong conviction that organizational researchers have much to gain as well as to offer by focusing on transitional economies, I undertook this study to examine characteristics of a regulatory environment and the impact on innovation and risk-taking among Chinese managers and entrepreneurs. I collected original primary data that represents managers from large state-owned enterprises (SOEs) and entrepreneurs from small privately-owned enterprises (POEs) through personal interviews and a survey. Significant differences were found between managers and entrepreneurs in their reported environmental characteristics, strategic orientations, size, and firm performance, indicating that managers are not as innovative and are less willing to make risky decisions than entrepreneurs. Being smaller and faster than SOEs, entrepreneurial firms have adopted some strategies that distinguish them from their larger and more established competitors. Speed, stealth, and sound execution allow entrepreneurs to harvest first-mover advantages and thus increase their chances for survival in a turbulent environment.

Multiple Positive Solutions of Semilinear Differential Equations with Singularities

Abstract: The existence of positive solutions of a second order differential equation of the form (formula here) with the separated boundary conditions: α z (0) − β z ′(0) = 0 and γ z (1)+δ z ′(1) = 0 has proved to be important in physics and applied mathematics. For example, the Thomas–Fermi equation, where f = z 3/2 and g = t −1/2 (see [ 12 , 13 , 24 ]), so g has a singularity at 0, was developed in studies of atomic structures (see for example, [ 24 ]) and atomic calculations [ 6 ]. The separated boundary conditions are obtained from the usual Thomas–Fermi boundary conditions by a change of variable and a normalization (see [ 22 , 24 ]). The generalized Emden–Fowler equation, where f = z p , p > 0 and g is continuous (see [ 24 , 28 ]) arises in the fields of gas dynamics, nuclear physics, chemically reacting systems [ 28 ] and in the study of multipole toroidal plasmas [ 4 ]. In most of these applications, the physical interest lies in the existence and uniqueness of positive solutions.

Hospital restructuring, work-family conflict and psychological burnout among nursing staff.

Abstract: This study examined work-family conflict, family-work conflict and psychological burnout among nursing staff during a time of hospital restructuring and downsizing. Data were collected from 686 hospital-based nurses, the vast majority women. Nurses reported significantly greater work-family conflict than family-work conflict. Personal demographics but not downsizing and restructuring stressors predicted family-work conflict; downsizing and restructuring stressors but not personal demographics predicted work-family conflict. Restructuring stressors and both work-family conflict and family-work conflict were associated with higher levels of psychological burnout.

Tolerance of temporal delay in virtual environments

Abstract: To enhance presence, facilitate sensory motor performance, and avoid disorientation or nausea, virtual-reality applications require the perception of a stable environment. End-end tracking latency (display lag) degrades this illusion of stability and has been identified as a major fault of existing virtual-environment systems. Oscillopsia refers to the perception that the visual world appears to swim about or oscillate in space and is a manifestation of this loss of perceptual stability of the environment. The effects of end-end latency and head velocity on perceptual stability in a virtual environment were investigated psychophysically. Subjects became significantly more likely to report oscillopsia during head movements when end-end latency or head velocity were increased. It is concluded that perceptual instability of the world arises with increased head motion and increased display lag. Oscillopsia is expected to be more apparent in tasks requiring real locomotion or rapid head movement.

Metalinguistic aspects of bilingual processing

Abstract: This chapter examines differences in metalinguistic development between monolingual and bilingual children in terms of three subcategories: word awareness, syntactic awareness, and phonological awareness. In each case, some studies have reported advantages for bilingual children, but equally, other studies have found either no difference between the groups, or, in some cases, monolingual advantages. In the discussion of each of these areas, the kinds of tasks for which bilingual and monolingual children perform differently are identified. In none of these three subcategories of metalinguistic awareness do bilingual children exhibit a uniform and consistent advantage over monolinguals. An alternate conception of metalinguistic ability is proposed in which two cognitive processes, analysis and control, are directly responsible for task performance. These processes are involved in all metalinguistic tasks but to different degrees. Re-examining the results in this way reveals that bilingual advantages occur reliably on tasks that make high demands on control but are not evident in tasks that make high demands on analysis. The implications of this pattern for metalinguistic ability are considered.

Mortality Derivatives and the Option to Annuitize

Abstract: Most U.S.-based insurance companies offer holders of their tax-sheltered savings plans (VAs), the long-term option to annuitize their policy at a pre-determined rate over a pre-specified period of time. Currently, there is approximately one trillion dollars invested in such policies, with guaranteed annuitization rates, in addition to any guaranteed minimum death benefit. The insurance company has essentially granted the policyholder an option on two underlying stochastic variables; future interest rates and future mortality rates. Although the (put) option on interest rates is obvious, the (put) option on mortality rates is not. Motivated by this product, this paper attempts to value (options on) mortality-contingent claims, by stochastically modelling the future hazard-plus-interest rate. Heuristically, we treat the underlying life annuity as a defaultable coupon-bearing bond, where the default occurs at the exogenous time of death. From an actuarial perspective, rather than considering the force of mortality (hazard rate) at time-t for a person now age-x, as a number, we view it as a random variable forward rate,whose expectation is the force of mortality in the classical sense. Our main qualitative observation is that both mortality and interest rate risk can be hedged, and the option to annuitize can be priced by locating a replicating portfolio involving insurance, annuities and default-free bonds. We provide both a discrete and continuous-time pricing framework.