Showing papers by "Concordia University published in 2013"

A review of the effects of physical activity and exercise on cognitive and brain functions in older adults.

Abstract: Studies supporting the notion that physical activity and exercise can help alleviate the negative impact of age on the body and the mind abound. This literature review provides an overview of important findings in this fast growing research domain. Results from cross-sectional, longitudinal, and intervention studies with healthy older adults, frail patients, and persons suffering from mild cognitive impairment and dementia are reviewed and discussed. Together these finding suggest that physical exercise is a promising nonpharmaceutical intervention to prevent age-related cognitive decline and neurodegenerative diseases.

Taste Regimes and Market-Mediated Practice

Abstract: Taste has been conceptualized as a boundary-making mechanism, yet there is limited theory on how it enters into daily practice. In this article, the authors develop a practice-based framework of taste through qualitative and quantitative analysis of a popular home design blog, interviews with blog participants, and participant observation. First, a taste regime is defined as a discursively constructed normative system that orchestrates practice in an aesthetically oriented culture of consumption. Taste regimes are perpetuated by marketplace institutions such as magazines, websites, and transmedia brands. Second, the authors show how a taste regime regulates practice through continuous engagement. By integrating three dispersed practices—problematization, ritualization, and instrumentalization—a taste regime shapes preferences for objects, the doings performed with objects, and what meanings are associated with objects. This study demonstrates how aesthetics is linked to practical knowledge and becomes materialized through everyday consumption.

Early Musical Training and White-Matter Plasticity in the Corpus Callosum: Evidence for a Sensitive Period

Abstract: Training during a sensitive period in development may have greater effects on brain structure and behavior than training later in life. Musicians are an excellent model for investigating sensitive periods because training starts early and can be quantified. Previous studies suggested that early training might be related to greater amounts of white matter in the corpus callosum, but did not control for length of training or identify behavioral correlates of structural change. The current study compared white-matter organization using diffusion tensor imaging in early- and late-trained musicians matched for years of training and experience. We found that early-trained musicians had greater connectivity in the posterior midbody/isthmus of the corpus callosum and that fractional anisotropy in this region was related to age of onset of training and sensorimotor synchronization performance. We propose that training before the age of 7 years results in changes in white-matter connectivity that may serve as a scaffold upon which ongoing experience can build.

Constraining the Ratio of Global Warming to Cumulative CO2 Emissions Using CMIP5 Simulations

Abstract: The ratio of warming to cumulative emissions of carbon dioxide has been shown to be approximately independent of time and emissions scenarios and directly relates emissions to temperature. It is therefore a potentially important tool for climate mitigation policy. The transient climate response to cumulative carbon emissions (TCRE), defined as the ratio of global-mean warming to cumulative emissions at CO2 doubling in a 1% yr−1 CO2 increase experiment, ranges from 0.8 to 2.4 K EgC−1 in 15 models from phase 5 of the Coupled Model Intercomparison Project (CMIP5)—a somewhat broader range than that found in a previous generation of carbon–climate models. Using newly available simulations and a new observational temperature dataset to 2010, TCRE is estimated from observations by dividing an observationally constrained estimate of CO2-attributable warming by an estimate of cumulative carbon emissions to date, yielding an observationally constrained 5%–95% range of 0.7–2.0 K EgC−1.

Convergent contemporary software peer review practices

Abstract: Software peer review is practiced on a diverse set of software projects that have drastically different settings, cultures, incentive systems, and time pressures. In an effort to characterize and understand these differences we examine two Google-led projects, Android and Chromium OS, three Microsoft projects, Bing, Office, and MS SQL, and projects internal to AMD. We contrast our findings with data taken from traditional software inspection conducted on a Lucent project and from open source software peer review on six projects, including Apache, Linux, and KDE. Our measures of interest include the review interval, the number of developers involved in review, and proxy measures for the number of defects found during review. We find that despite differences among projects, many of the characteristics of the review process have independently converged to similar values which we think indicate general principles of code review practice. We also introduce a measure of the degree to which knowledge is shared during review. This is an aspect of review practice that has traditionally only had experiential support. Our knowledge sharing measure shows that conducting peer review increases the number of distinct files a developer knows about by 66% to 150% depending on the project. This paper is one of the first studies of contemporary review in software firms and the most diverse study of peer review to date.

The impact of the dimensions of social performance on firm risk

Abstract: This paper examines the impact of the individual dimensions of social performance (SP) on firm risk (total and idiosyncratic) using 16,599 firm-year observations over the period 1991–2007. We find that firm risk for S&P500 members is positively affected by Employee, Diversity, and Corporate Governance concerns. On the other hand, Community (Diversity) strengths negatively (positively) affect their risk. As to non-S&P500 members, firm risk is positively affected by Employee concerns and Diversity strengths. However, firm risk of non-S&P500 members is negatively affected by Environment strengths. The direction of causation between firm risk and SP depends on the dimension examined.

Beyond significance testing: Statistics reform in the behavioral sciences, 2nd ed.

Abstract: Traditional education in statistics that emphasises significance testing leaves researchers and students ill prepared to understand what their results really mean. Specifically, most researchers and students who do not have strong quantitative backgrounds have difficulty understanding outcomes of statistical tests. As more and more people become aware of this problem, the emphasis on statistical significance in the reporting of results is declining. Increasingly, researchers are expected to describe the magnitudes and precisions of their findings and also their practical, theoretical, or clinical significance. This accessibly written book reviews the controversy about significance testing, which has now crossed various disciplines as diverse as psychology, ecology, commerce, education, and biology, among others. It also introduces readers to alternative methods, especially effect size estimation (at both the group and case levels) and interval estimation (confidence intervals) in comparative studies. Basics of bootstrapping and Bayesian estimation are also considered. Research examples from substance abuse, education, learning, and other areas illustrate how to apply these methods. A companion website promotes learning by providing chapter exercises and sample answers, downloadable raw data files for many research examples, and links to other useful websites. New to this edition is coverage of robust statistical methods for parameter estimation, effect size estimation, and interval estimation. A new chapter covers the logic and illogic of significance testing. This edition also addresses recent developments such as the new requirements of some journals for the reporting of effect sizes.

Is Environmental Governance Substantive or Symbolic? An Empirical Investigation.

Abstract: The emergence of environmental governance practices raises a fundamental question as to whether they are substantive or symbolic. Toward that end, we analyze the relationship between a firm’s environmental governance and its environmental management as reflected in its ultimate outcome, environmental performance. We posit that substantive practices would bring changes in organizations, most notably in terms of improved environmental performance, whereas symbolic practices would portray organizations as environmentally committed without making meaningful changes to their operations. Focusing on a sample of environmentally sensitive firms, results are consistent with environmental governance mechanisms being predominantly part of a symbolic approach to manage stakeholder perceptions on environmental management, having little substantial impact on organizations. Statistical analyses show mostly that there is no relation between environmental governance mechanisms and environmental performance, measured in terms of regulatory compliance, pollution prevention, and environmental capital expenditures. However, there is some indication that environmental incentives are associated with pollution prevention. Interviews with corporate directors shed further light on these results by underlining that environmental governance mechanisms are employed at the board level to protect the organization from reputational and/or regulatory harm, but are not necessarily intended to proactively improve environmental performance.

Does “Good” Corporate Governance Help in a Crisis? The Impact of Country- and Firm-Level Governance Mechanisms in the European Financial Crisis

Abstract: Manuscript Type Empirical Research Question/Issue We examine the effects of firm- and country-level “good” corporate governance prescriptions on firm performance before and during the recent financial crisis, using a large sample of 1,197 firms across 26 European countries. Research Findings/Insights We propose a contextualized agency perspective suggesting that firm- and country-level good governance prescriptions designed to assure managerial oversight may not hold in a financial crisis. This is because firms can benefit from broadening managerial discretion so as to facilitate the exercise of initiative and decisive leadership. Overall, our firm- and country-level findings support this argument. In a crisis, CEO duality is associated with better performance. We also find that the use of incentive compensation and the existence of a wedge between ownership and control rights negatively impacts on firm performance in a crisis. Hierarchical linear modeling shows that 25 percent of the heterogeneity in firm performance is among countries, indicating the importance of including country-level institutions in our analyses. In a crisis, we find that the general quality of the legal system and creditor rights protection are positively related to firm performance, but protection for equity investors is not. Theoretical/Academic Implications The findings challenge the universality of good governance prescriptions and contribute to the growing body of work proposing that the efficacy of governance mechanisms may be contingent upon organizational and environmental circumstances. Practitioner/Policy Implications The study offers insights relevant to policy and practitioner communities, showing that governance mechanisms operate differently in crisis and non-crisis periods. The tendency to respond to a crisis with more stringent rules may be counterproductive since such measures may compromise executives' ability to respond appropriately to systemic shocks. Practitioners are encouraged to optimize rather than maximize their governance choices.

Development of advanced FDD and FTC techniques with application to an unmanned quadrotor helicopter testbed

Abstract: As the first part, this paper presents an overview on the existing works on fault detection and diagnosis (FDD) and fault-tolerant control (FTC) for unmanned rotorcraft systems. Considered faults include actuator and sensor faults for single and multi-rotor systems. As the second part, several FDD and FTC techniques developed recently at the Networked Autonomous Vehicles Lab of Concordia University are detailed along with experimental application to a unique and newly developed quadrotor helicopter testbed.

Phenotypically plastic neophobia: a response to variable predation risk

Abstract: Prey species possess a variety of morphological, life history and behavioural adaptations to evade predators. While specific evolutionary conditions have led to the expression of permanent, non-plastic anti-predator traits, the vast majority of prey species rely on experience to express adaptive anti-predator defences. While ecologists have identified highly sophisticated means through which naive prey can deal with predation threats, the potential for death upon the first encounter with a predator is still a remarkably important unresolved issue. Here, we used both laboratory and field studies to provide the first evidence for risk-induced neophobia in two taxa (fish and amphibians), and argue that phenotypically plastic neophobia acts as an adaptive anti-predator strategy for vulnerable prey dealing with spatial and temporal variation in predation risk. Our study also illustrates how risk-free maintenance conditions used in laboratory studies may blind researchers to adaptive anti-predator strategies that are only expressed in high-risk conditions.

Dreaming as mind wandering: evidence from functional neuroimaging and first-person content reports

Abstract: Isolated reports have long suggested a similarity in content and thought processes across mind wandering (MW) during waking, and dream mentation during sleep. This overlap has encouraged speculation that both ‘daydreaming’ and dreaming may engage similar brain mechanisms. To explore this possibility, we systematically examined published first-person experiential reports of MW and dreaming and found many similarities: in both states, content is largely audiovisual and emotional, follows loose narratives tinged with fantasy, is strongly related to current concerns, draws on long-term memory, and simulates social interactions. Both states are also characterized by a relative lack of meta-awareness. To relate first-person reports to neural evidence, we compared meta-analytic data from numerous functional neuroimaging (PET, fMRI) studies of the default mode network (DMN, with high chances of MW) and rapid eye movement (REM) sleep (with high chances of dreaming). Our findings show large overlaps in activation patterns of cortical regions: similar to MW/DMN activity, dreaming and REM sleep activate regions implicated in self-referential thought and memory, including medial prefrontal cortex (PFC), medial temporal lobe structures, and posterior cingulate. Conversely, in REM sleep numerous PFC executive regions are deactivated, even beyond levels seen during waking MW. We argue that dreaming can be understood as an ‘intensified’ version of waking MW: though the two share many similarities, dreams tend to be longer, more visual and immersive, and to more strongly recruit numerous key hubs of the DMN. Further, whereas MW recruits fewer PFC regions than goal-directed thought, dreaming appears to be characterized by an even deeper quiescence of PFC regions involved in cognitive control and metacognition, with a corresponding lack of insight and meta-awareness. We suggest, then, that dreaming amplifies the same features that distinguish MW from goal-directed waking thought.

The role of supervisor autonomy support, organizational support, and autonomous and controlled motivation in predicting employees' satisfaction and turnover intentions

Abstract: Using self-determination theory (Deci & Ryan, 2008) as the guiding theoretical framework, the present study tested a model that incorporates workers' perceptions of organizational support and supervisor autonomy support, global and domain specific (i.e., work) motivation, work satisfaction, and turnover intentions. The hypothesized model was tested using a sample of 735 workers (362 men and 373 women). Results revealed that work motivation was significantly related to both intraindividual (global motivation) and contextual factors (organizational support and supervisor autonomy support). In addition, perceived organizational support and work autonomous motivation were positively related to work satisfaction, whereas turnover intentions were negatively related to perceived organizational support and work autonomous motivation, and positively related to work controlled motivation. The present results underscore the importance of understanding the mechanisms through which higher turnover intentions and lower...

Rethinking biodiversity: from goods and services to “living with”

Abstract: Since the 1992 Convention on Biological Diversity, counting and mapping have come to dominate international debates around biodiversity protection. With the emergence of the Ecosystem Services concept, these counting and mapping efforts are increasingly imbued with an economic logic that argues that to save biodiversity, its goods and services must be given monetary value. This article offers a critical engagement with the Ecosystem Services discourse and the way it translates the diversity of nature into a single measure—a “currency”—to be included in systems of exchange. We argue that this conception of biodiversity is too narrow and potentially detrimental because it reduces biodiversity to a series of quantifiable fragmented parts that become liable to counting, mapping, and utilitarian use, and because it reduces social–natural relations to market transactions. Subsequently, we outline possibilities for conceiving and living with biodiversity that go beyond relations of counting, mapping, and commodification. It is important that biodiversity knowledge organizations, such as the recently sanctioned Intergovernmental science-policy Platform on Biodiversity and Ecosystem Services (IPBES), take these into account. Conserving a diversity of life requires acknowledging a diversity of values, knowledge and framings of biodiversity, and fostering a diversity of social–natural relations.

Computer-Aided Breast Cancer Diagnosis Based on the Analysis of Cytological Images of Fine Needle Biopsies

Abstract: The effectiveness of the treatment of breast cancer depends on its timely detection. An early step in the diagnosis is the cytological examination of breast material obtained directly from the tumor. This work reports on advances in computer-aided breast cancer diagnosis based on the analysis of cytological images of fine needle biopsies to characterize these biopsies as either benign or malignant. Instead of relying on the accurate segmentation of cell nuclei, the nuclei are estimated by circles using the circular Hough transform. The resulting circles are then filtered to keep only high-quality estimations for further analysis by a support vector machine which classifies detected circles as correct or incorrect on the basis of texture features and the percentage of nuclei pixels according to a nuclei mask obtained using Otsu's thresholding method. A set of 25 features of the nuclei is used in the classification of the biopsies by four different classifiers. The complete diagnostic procedure was tested on 737 microscopic images of fine needle biopsies obtained from patients and achieved 98.51% effectiveness. The results presented in this paper demonstrate that a computerized medical diagnosis system based on our method would be effective, providing valuable, accurate diagnostic information.

Blind Dates and Arranged Marriages: Longitudinal Processes of Network Orchestration

Abstract: Using longitudinal qualitative and network data capturing five years of evolution of an interorganizational network, this paper explores network orchestration – the process of assembling and developing an interorganizational network. In particular, we analyze shifts in the network orchestrator’s actions and the network’s structure and composition. We find that an orchestrator builds the capacity to assemble a network over time through the accumulation of resources and specialized expertise. However, as the network develops, an orchestrator faces an evolving set of dilemmas arising from the need to demonstrate value for various members and audiences. To resolve these dilemmas, orchestrators may shift their actions, moving from initially encouraging serendipitous encounters between network members (“blind dates”) to increasingly selecting members and more closely influencing their interactions (“arranging marriages”). We discuss implications of our findings for a processual understanding of orchestrated net...

Communication security for smart grid distribution networks

Abstract: The operation and control of the next generation electrical grids will depend on a complex network of computers, software, and communication technologies. Being compromised by a malicious adversary would cause significant damage, including extended power outages and destruction of electrical equipment. Moreover, the implementation of the smart grid will include the deployment of many new enabling technologies such as advanced sensors and metering, and the integration of distributed generation resources. Such technologies and various others will require the addition and utilization of multiple communication mechanisms and infrastructures that may suffer from serious cyber vulnerabilities. These need to be addressed in order to increase the security and thus the greatest adoption and success of the smart grid. In this article, we focus on the communication security aspect, which deals with the distribution component of the smart grid. Consequently, we target the network security of the advanced metering infrastructure coupled with the data communication toward the transmission infrastructure. We discuss the security and feasibility aspects of possible communication mechanisms that could be adopted on that subpart of the grid. By accomplishing this, the correlated vulnerabilities in these systems could be remediated, and associated risks may be mitigated for the purpose of enhancing the cyber security of the future electric grid.

Handgrip strength predicts survival and is associated with markers of clinical and functional outcomes in advanced cancer patients

Abstract: Handgrip strength (HGS) has been shown to predict survival and is associated with changes in body composition, nutritional status, inflammation, and functional ability in several chronic disease conditions. Whether similar relationships exist between HGS and clinical outcomes in patients with advanced cancer are currently unknown. We evaluated the association between HGS and survival as well as several key markers of body composition (e.g., sarcopenia), subjective performance measures (e.g., quality of life), and muscle strength (e.g., isokinetic torque of the quadriceps) in patients with advanced forms of non-small cell lung and gastrointestinal cancers. A consecutive cohort of 203 patients with advanced cancer was enrolled and categorized into three HGS percentiles (e.g., ≥50th, 25th, and ≤10th) according to published normative values. Multivariate regression analyses were used to test for independent associations between HGS and survival, sarcopenia, quality of life (QoL), and lower extremity muscle strength as well as key biological markers (e.g., hemoglobin, albumin, and C-reactive protein) while controlling for age, gender, cancer diagnosis, treatment (chemotherapy/radiotherapy), medications, and time from diagnosis to assessment. When compared to HGS ≥50th, patients in the HGS ≤10th percentile had lower BMI (B, −2.5 kg/m2; 95% CI, −4.5 to −0.45), shorter survival (hazard ratio, 3.2; 2.0–5.1), lower hemoglobin (−19.70 g/L; −27.28 to −12.13) and albumin (−4.99 g/L; −7.85 to −2.13), greater occurrence of sarcopenia (odds ratio, 9.53; 1.95–46.55), lower isokinetic torque of the quadriceps at both 60°/s (−30.6 Nm; −57.9 to −3.3) and 120°/s (−25.1 Nm; −46.4 to −3.7), lower QoL (−1.6 on McGill Quality of Life Questionnaire scale; −2.5 to −0.6), higher levels of fatigue (18.8 on Brief Fatigue Inventory scale; 4.7 –32.9), poorer performance status (0.75 on Eastern Cooperative Oncology Group Performance Status scale; 0.34–1.15), lower fat mass (−7.4 kg; −14.4 to −0.5), and lower lean body mass (−6.5 kg; −10.3 to −2.8). HGS is independently associated with survival and important biological, functional, and quality of life characteristics in advanced cancer patients. Patients presenting with very low percentiles with respect to their handgrip assessment may require timely referral to supportive and/or palliative care services.

Neural-Adaptive Control of Single-Master–Multiple-Slaves Teleoperation for Coordinated Multiple Mobile Manipulators With Time-Varying Communication Delays and Input Uncertainties

Abstract: In this paper, adaptive neural network control is investigated for single-master-multiple-slaves teleoperation in consideration of time delays and input dead-zone uncertainties for multiple mobile manipulators carrying a common object in a cooperative manner. Firstly, concise dynamics of teleoperation systems consisting of a single master robot, multiple coordinated slave robots, and the object are developed in the task space. To handle asymmetric time-varying delays in communication channels and unknown asymmetric input dead zones, the nonlinear dynamics of the teleoperation system are transformed into two subsystems through feedback linearization: local master or slave dynamics including the unknown input dead zones and delayed dynamics for the purpose of synchronization. Then, a model reference neural network control strategy based on linear matrix inequalities (LMI) and adaptive techniques is proposed. The developed control approach ensures that the defined tracking errors converge to zero whereas the coordination internal force errors remain bounded and can be made arbitrarily small. Throughout this paper, stability analysis is performed via explicit Lyapunov techniques under specific LMI conditions. The proposed adaptive neural network control scheme is robust against motion disturbances, parametric uncertainties, time-varying delays, and input dead zones, which is validated by simulation studies.

Cartography I Mapping narrative cartography

Abstract: This report focuses on the growing interest in the relationship between maps, narratives and meta-narratives. Following a brief historical contextualization of these relationships, this report explores their current state in the Geoweb era. Using the distinction between story maps and grid maps as an analytical framework, I review emerging issues around the extensive use of technologies and online mapping services (i.e. Google maps) to convey stories and to produce new ones. Drawing on literature in film studies, literary studies, visual arts, computer science and communication I also emphasize the emergence of new forms of spatial expressions interested in providing different perspectives about places and about stories associated to places. In sum, I argue that mapping both vernacular knowledge and fiction is central understanding places in depth.

Montreal Cognitive Assessment (MoCA): Concept and Clinical Review

Abstract: The Montreal Cognitive Assessment (MoCA) is a cognitive screening instrument developed to detect mild cognitive impairment (MCI). It is a simple 10 min paper and pencil test that assesses multiple cognitive domains including memory, language, executive functions, visuospatial skills, calculation, abstraction, attention, concentration, and orientation. Its validity has been established to detect mild cognitive impairment in patients with Alzheimer’s disease and other pathologies in cognitively impaired subjects who scored in the normal range on the MMSE. MoCA’s sensitivity and specificity to detect subjects with MCI due to Alzheimer’s disease and distinguish them from healthy controls are excellent. MoCA is also sensitive to detect cognitive impairment in cerebrovascular disease and Parkinson’s disease, Huntington’s disease, brain tumors, systemic lupus erythematosus, substance use disorders, idiopathic rapid eye movement sleep behavior disorder, obstructive sleep apnea, risk of falling, rehabilitation outcome, epilepsy, chronic obstructive pulmonary disease and human immunodeficiency virus infection. There are several features in MoCA’s design that likely explain its superior sensitivity for detecting MCI. MoCA’s memory testing involves more words, fewer learning trials, and a longer delay before recall than the MMSE. Executive functions, higher-level language abilities, and complex visuospatial processing can also be mildly impaired in MCI participants of various etiologies and are assessed by the MoCA with more numerous and demanding tasks than the MMSE. MoCA was developed in a memory clinic setting and normed in a highly educated population. A new version of the MoCA called MoCA-Basic (MoCA-B) was developed to fulfill the limitation of the MoCA among the low educated and illiterate population. MoCA Memory Index Score is a newly devised score that can help clinicians better predict which patients with MCI are most likely to convert to dementia. The MoCA is freely accessible for clinical and educational purposes (www.mocatest.org), and is available in 56 languages and dialects.

Compressive sensing-based channel estimation for massive multiuser MIMO systems

Abstract: We propose a new approach based on compressive sensing (CS) for the channel matrix estimation problem for “massive” (or large-scale) multiuser (MU) multiple-input multiple-output (MIMO) systems. The system model includes a base station (BS) equipped with a very large number of antennas communicating simultaneously with a large number of autonomous single-antenna user terminals (UTs), over a realistic physical channel with finite scattering model. Based on the idea that the degree of freedom of the channel matrix is smaller than its large number of free parameters, a low-rank matrix approximation based on CS is proposed and solved via a quadratic semidefine programming (SDP). Our analysis and experimental results suggest that the proposed method outperforms the existing ones in terms of estimation error performance or training transmit power, without requiring any knowledge about the statistical distribution or physical parameters of the propagation channel.