York University
  • Toronto, Ontario, Canada
Recent publications
Spaced learning—the spacing effect—is a cognitive phenomenon whereby memory for to-be-learned material is better when a fixed amount of study time is spread across multiple learning sessions instead of crammed into a more condensed time period. The spacing effect has been shown to be effective across a wide range of ages and learning materials, but few studies have been conducted that look at whether spacing can be effective in real-world classrooms, using real curriculum content, with real teachers leading the intervention. In the current study, lesson plans for teaching website credibility were distributed to homeroom elementary teachers with specific instructions on how to manipulate the timing of the lessons for either a one-per-day or one-per-week delivery. One month after the final lesson, students were asked to apply their knowledge on a final test, where they evaluated two new websites. Results were mixed, suggesting that classroom noise might lessen or impede researchers’ ability to find spacing effects in naturalistic settings.
Athlete selection (often referred to as talent selection) reflects the end point of what is a complex decision-making process coaches, administrators, and/or scouts use when deciding who remains and who is removed from a sample of potential athletes. In this paper, we conceptualize athlete selection as an evolutionary process where selection pressures (e.g., performance demands, system limitations) influence the value of one trait/characteristic over another. Athletes are selected either through demonstrating enhanced performance (survival advantages) or by having characteristics that are desirable to the coach/recruiter making the selection (attraction advantages). Based on these varying pressures, our understanding of whether profiles of current athletes represent the actual elements of performance necessary for success or simply those most needed for selection at key points in athlete development is extremely limited.
The application of post-exercise cooling (e.g., cold water immersion) and post-exercise heating has become a popular intervention which is assumed to increase functional recovery and may improve chronic training adaptations. However, the effectiveness of such post-exercise temperature manipulations remains uncertain. The aim of this comprehensive review was to analyze the effects of post-exercise cooling and post-exercise heating on neuromuscular function (maximal strength and power), fatigue resistance, exercise performance, and training adaptations. We focused on three exercise types (resistance, endurance and sprint exercises) and included studies investigating (1) the early recovery phase, (2) the late recovery phase, and (3) repeated application of the treatment. We identified that the primary benefit of cooling was in the early recovery phase (< 1 h post-exercise) in improving fatigue resistance in hot ambient conditions following endurance exercise and possibly enhancing the recovery of maximal strength following resistance exercise. The primary negative impact of cooling was with chronic exposure which impaired strength adaptations and decreased fatigue resistance following resistance training intervention (12 weeks and 4–12 weeks, respectively). In the early recovery phase, cooling could also impair sprint performance following sprint exercise and could possibly reduce neuromuscular function immediately after endurance exercise. Generally, no benefits of acute cooling were observed during the 24–72-h recovery period following resistance and endurance exercises, while it could have some benefits on the recovery of neuromuscular function during the 24–48-h recovery period following sprint exercise. Most studies indicated that chronic cooling does not affect endurance training adaptations following 4–6 week training intervention. We identified limited data employing heating as a recovery intervention, but some indications suggest promise in its application to endurance and sprint exercise.
Background There is no region-specific publication investigating the attributable burden of breast cancer, particularly among females. This article reported the burden of female breast cancer in the Middle East and North Africa (MENA) region, and its attributable risk factors between 1990 and 2019, by age, sex, and socio-demographic index (SDI). Methods Publicly available data on the incidence, death and disability-adjusted life years (DALY) were retrieved from the Global Burden of Disease (GBD) 2019 study for the 21 countries and territories in MENA, between 1990 and 2019, along with 95% uncertainty intervals (UIs). The relationship between the burden of female breast cancer, in terms of DALYs, and the SDI were also assessed using Smoothing Spline models. Results In 2019, the regional age-standardised incidence and death rates of female breast cancer were 37.5 and 15.2 per 100,000, which represent a 90.9 and 24.0% increase since 1990, respectively. In addition, in 2019 the regional age-standardised DALY rate was 472.7 per 100,000, which was 19.5% higher than in 1990. In 2019, the death rate increased steadily with advancing age, while the DALY rate increased steeply with age and reached its peak in the 70–74 age group. There was a positive association between SDI and the burden of breast cancer over the period 1990 to 2019. Moreover, in 2019 high fasting plasma glucose (6.9%) contributed to the largest proportion of attributable DALYs for female breast cancer in the MENA region. Conclusions There was a significant increase in the incidence rate of female breast cancer in MENA over the past three decades, although the death and DALY rates were both largely unchanged. Preventive programs targeting the major risk factors should be implemented in the region.
Background Internet-delivered cognitive behavioral therapy (ICBT) for alcohol misuse has potential to radically improve access to evidence-based care, and there is a need to investigate ways to optimize its delivery in clinical settings. Guidance from a clinician has previously been shown to improve drinking outcomes in ICBT, and some studies suggest that pre-treatment assessments may contribute in initiating early change. The objective of this study was to investigate the added and combined effects of a pre-treatment assessment interview and guidance on the outcomes of ICBT for alcohol misuse delivered in an online therapy clinic. Methods A 2X2 factorial randomized controlled trial was conducted where participants received access to an 8-week ICBT program, and either a pre-treatment assessment interview (Factor 1), guidance (Factor 2), a combination of these, or neither of these. Participants were 270 individuals (66.8% female, mean age = 46.5) scoring 8 or more on the Alcohol Use Disorders Identification Test and consuming 14 standard drinks or more in the preceding week. Primary outcomes were number of drinks consumed and number of heavy drinking days during the preceding week, 3 months post-treatment. Results Large within-group effects were found in terms of alcohol reductions (d w ≥ 0.82, p < 0.001), but neither of the factors significantly improved drinking outcomes. Guidance was associated with greater adherence (i.e. completed modules). Conclusions Neither a pre-treatment assessment interview nor guidance from a clinician appears to improve drinking outcomes resulting from internet-delivered cognitive behaviour therapy for alcohol misuse when delivered in a routine online therapy clinic. Trial registration: NCT03984786. Registered 13 June 2019, https://clinicaltrials.gov/ct2/show/NCT03984786
We formulate and analyze a general reaction-diffusion equation with delay, inspired by age-structured spruce budworm population dynamics with spatial diffusion by matured individuals. The model has its particular feature for bistability due to the incorporation of a nonlinear birth function (Ricker's function) and a Holling type function of predation by birds. Here we establish some results about the global dynamics, in particular, the stability of and global Hopf bifurcation from the spatially homogeneous steady state when the maturation delay is taken as a bifurcation parameter. We also use a degree theoretical argument to identify intervals for the diffusion rate when the model system has a spatially heterogeneous steady state. Numerical experiments presented show interesting spatialtemporal patterns.
In this paper, we propose a time-periodic reaction–diffusion model with environment transmission and spatial heterogeneity to describe the transmission of avian influenza virus between birds, poultry and human population. Firstly, we study the well-posedness of solutions, including the existence and boundedness of global solutions and the existence of the global attractor of solution semiflow. Then, the basic reproduction number R0 of the model is defined, and we prove R0 is a threshold determining the global dynamics of the model. Furthermore, we analyze the dynamic behavior of the autonomous reaction–diffusion model, and obtain the existence and global attractivity of endemic equilibrium. Finally, we give some numerical examples and simulations to illustrate the main theoretical results and investigate the impacts of some model parameters on R0.
We develop the theory of pretty good fractional revival in quantum walks on graphs using their Laplacian matrices as the Hamiltonian. We classify the paths and the double stars that have Laplacian pretty good fractional revival.
Our ability to understand the world around us hinges on our cognition. Theoretically, children’s abilities improve with age; however, a lively discussion exists on how factors such as task domain, task interference, and task difficulty, as indexed mainly by relevant cues, affect cognitive performance. Practically, cognitive measures take a substantial amount of time to administer, which poses limitations for researchers in the field of psychology. The current study addressed theoretical and practical questions regarding the nature of child cognition using full and abbreviated versions of classic, recent, and new tasks of mental attentional capacity. We employed a cross-sectional design testing 483 participants in six groups (7–30 years of age) on the new Number Matching Task (NMT), the established Color Matching Task (CMT), and the classic Figural Intersection Task (FIT). Results confirm theoretical predictions of the developmental increase in mental attentional capacity and the adjunct hypothesis that tasks with high interference are better to assess the developmental trajectory of mental attentional capacity quantitatively. NMT scores are significantly equivalent to CMT scores and the theoretically predicted mental attentional capacity, and the abbreviated CMT and NMT produce comparable scores to those of the full tests. We determined that the NMT can be administered developmentally and is appropriate for use in assessing mental attentional capacity in studies with both children and adults.
Based on Hunt and Vitell’s theory of ethics, using three vignettes, we tested intrinsic and extrinsic religiosities and five ethical principles (justice, deontology, relativism, egoism, and utilitarianism) in the ethical decision-making process of 232 Indian business professionals. Intrinsic religiosity is positively related to ethical recognition and intent and extrinsic religiosity is negatively related to ethical intent in the vignette concerning duty of care. Although intrinsic religiosity predicted justice, deontology and relativism in three vignettes, it is also positively related to utilitarianism in one vignette. Egoism is not related to intrinsic and extrinsic religiosities. Extrinsic religiosity is negatively related to justice (one vignette), deontology (two vignettes), relativism (two vignettes) and utilitarianism (one vignette). Moreover, the intrinsic religiosity-ethical recognition and extrinsic religiosity-ethical intent relationships are varyingly mediated by the ethical principles. We extend Hunt and Vitell’s theory in a multi-faith context and our findings have implications for Indian business leaders and employees.
Three distributed circuit-based approaches based on Hopkinson analogy, Buntenbach analogy and duality principle are proposed in this paper to provide a detailed electromagnetic model of an inductor. The proposed approaches can provide several important aspects of finite element method (FEM), such as detailed geometrical representation and incorporation of magnetic saturation. In comparison to FEM, which has numerous obstacles in studying a magnetic device in a large network, the proposed approaches can be implemented in electromagnetic transient (EMT)-type software and thus can simulate the magnetic devices in a large network. The three circuit-based methods are first compared to each other, and then a 2-D finite-element method is used to validate them.
Enzymatic degradation of elastin by matrix metalloproteinases (MMPs) leads to the permanent dilation of aortic wall and constitutes the most prominent characters of aortic aneurysm and aging-related medial degeneration. Hydrogen sulfide (H2S) as a gasotransmitter exhibits a wide variety of cardio-protective functions through its anti-inflammatory and anti-oxidative actions. Cystathionine gamma-lyase (CSE) is a main H2S-generating enzyme in cardiovascular system. The regulatory roles of CSE/H2S system on elastin homeostasis and blood vessel degeneration have not yet been explored. Here we found that aged CSE knockout mice had severe aortic dilation and elastic degradation in abdominal aorta and were more sensitive to angiotensin II-induced aortic elastolysis and medial degeneration. Administration of NaHS would protect the mice from angiotensin II-induced inflammation, gelatinolytic activity, elastin fragmentation, and aortic dilation. In addition, human aortic aneurysm samples had higher inflammatory infiltration and lower expression of CSE. In cultured smooth muscle cells (SMCs), TNFα-induced MMP2/9 hyperactivity and elastolysis could be attenuated by exogenously applied NaHS or CSE overexpression while further deteriorated by complete knockout of CSE. It was further found that H2S inhibited MMP2 transcription by posttranslational modification of Sp1 via S-sulfhydration. H2S also directly suppressed MMP hyperactivity by S-sulfhydrating the cysteine switch motif. Taken together, this study revealed the involvement of CSE/H2S system in the pathogenesis of aortic elastolysis and medial degeneration by maintaining the inactive form of MMPs, suggesting that CSE/H2S system can be a target for the prevention of age-related medial degeneration and treatment of aortic aneurysm.
In this paper, a 6 degrees of freedom (DOFs) generalized parallel manipulator is presented which can be used as a humanoid leg. Based on the Number Synthesis and Graph Synthesis method, all the possible contracted graphs of the 6-DOFs leg are provided. Then, a novel method named as Node Response Method (NRM) is presented to identify the isomorphism of contracted graphs. In order to obtain the optimal manipulator, the Lie group is used to analyze all limbs. Furthermore, a terrain adaptive index named as Global Maximum Stride Distance Ratio (GMSDR) is established, which is used to assess the performance of a biped robot in different terrains. The DOF of proposed manipulator is verified by translating into a two-layer and two-loop (TL-TL) topological structure. Afterwards, the kinematics and the Jacobian matrix of the manipulator are calculated. Moreover, the performance indexes of the manipulator are analyzed. In order to obtain an optimal kinematics performance, the structural parameters are optimized using genetic algorithm. Finally, two basic gaits are proposed for a biped robot which consists of two manipulators and a simulation is carried out.
This article, based on the typical discrete-time semi-martingale convergence theorem, establishes several generalized versions of invariance principle for describing the long-term dynamical behaviors of discrete-time stochastic dynamical systems. These principles are suitable for investigating the dynamics in autonomous or non-autonomous systems and their applicability is demonstrated via using several representative examples. Particularly for autonomous systems, the established principle renders it possible to estimate the time when an orbit, initiating outside a particular bounded set, finally enters it. Furthermore, we provide a generalized version of discrete-time semi-martingale convergence theorem, and offer a counterexample to urge attentions to some delicate conditions that must be taken into account in the use of some version of convergence theorem.
Thresholding estimators such as the existing square-root and LAD LASSO, and the new affine and GLM LASSO with new link functions, have the ability to set coefficients to zero. They will yield new pivotal statistics which enjoy high power under sparse or dense alternative hypotheses. Under a general formalism, thresholding tests not only recover existing tests such as Rao score test and Fisher nonparametric sign test, but also unveil new tests, for the global/omnibus hypothesis in high dimension in particular. Although pivotal, the new statistics do not have a known distribution, so the critical value of the test is calculated by straightforward Monte Carlo, which yields exact level and high power as illustrated on simulated data.
Microbes swimming in a fluid that contains nanoparticles is an intriguing characteristic having ramifications in biomedicine, petroleum science, biofuels, and biotechnology applications. This study gives a theoretical evaluation of the bioconvection phenomena with swimming microorganisms in a Prandtl–Erying nanofluid constructed by an exponential stretched surface, given the amazing applications of bioconvection and nanoparticles. Additionally, the problem is modeled by considering intriguing phenomena such as thermophoretic particle deposition, Darcy–Forchheimer medium, exothermic/endothermic process, and activation energy vitality. The leading problem comprises nonlinear, coupled, partial differential expressions. To run the appraisal process, the controlling problem is transfigured into dimensionless patterns through the usual transformations. A computational finite difference approach is used to quantify the numerical evaluation of fabricated flow problems. To obtain the parametric constraints, stability and convergency were also assessed. Improved visualizations (streamlines, isothermal line, iso‐concentration, iso‐microorganisms) of ongoing flow fields are also illustrated. It is unveiled that the augmentation in velocity ratio factor improves nanofluid velocity and its related boundary layer wideness. The concentration of microbes and nanoparticles is reduced against the bio‐Lewis number and Lewis number precisely. The rate of change in heat transfer is the highest for the presence/absence of the thermophoresis factor. Moreover, Entropy production and Bejan number display the reverse impact for the Brinkman number. The change in entropy rate is 30.60% for the presence/absence of microbes' diffusion parameter. This evaluation could help reduce energy waste and improve the performance and efficiency of industrial and engineering appliances like nuclear power plants, and solar energy production.
The Origins, Spectral Interpretation, Resource Identification, and Security–Regolith Explorer (OSIRIS-REx) mission revealed that the asteroid Bennu has ~1500 impact craters (Bierhaus et al., 2022). Here we use data from the OSIRIS-REx laser altimeter (OLA) to measure the depths, d, and diameters, D, of a sample of small (D ≤ 10 m) impact craters that span a broad range of latitudes and longitudes. d/D in this sample ranges from 0.04 to 0.27, with a mean of 0.13 ± 0.04. Compared to larger (D ≥ 10 m) craters on Bennu, those studied here have a greater average d/D. The mean d/D of craters on Bennu's younger, Rugged Unit is statistically larger than the mean d/D of those on the older, Smooth Unit. One of the studied craters contains an interior mound that may indicate the presence of stronger material at depth. A large fraction of craters studied here are located near large boulders whose lengths are >50% the diameter of the crater. Some of these large boulders cross the crater rim crest, protruding into and perched above the crater interior. In the most extreme cases, the boulder length is ~2.5 times the crater diameter. The d/D of craters near large boulders is bimodal, which could be a consequence of how boulders affect crater formation. Laboratory experiments and results from Hayabusa2's Small Carry-On Impactor experiment indicate that preexisting boulders and heterogeneities affect crater formation and d/D. The abundance of small craters on Bennu makes the asteroid a rich resource for understanding impact processes.
Potentially toxic elements (PTEs), persistent organic pollutants, and emerging contaminants make sewage sludge management challenging. There is significant interest in thermal treatment technologies that can destroy these compounds. The most common thermal treatment, incineration, poses risks due to formation and/or release of hazardous substances in process emissions such as polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs) and PTEs. Smouldering has been introduced recently as a potential treatment for managing sewage sludge. Smouldering systems present several advantages over traditional incinerators; however, there are still uncertainties regarding process by-products. This key question was investigated in three laboratory-scale tests (0.08 m radius) and five oil drum-scale tests (0.3 m radius) that were evaluated for PCDD/Fs and PTEs in the mixture before and after treatment as well as in process emissions. Volatile organic compounds (VOCs) were also measured. These experiments represent a broad spectrum of conditions to evaluate process emissions, from robust self-sustaining to extinction of smouldering. Robust smouldering had negligible PCDD/Fs in process emissions. Weak smouldering had low levels of PCDD/Fs (emissions factor: 3.3 ± 0.3 μg TEQ/Mg dried sludge destroyed), levels less than uncontrolled emissions from commercial incinerators. Overall, smouldering acted as a sink for PCDD/Fs, as only 0–3% of the PCDD/Fs originally present in the sludge were released in the emissions, and >99% of the remainder were destroyed with <1% remaining in post-treatment ash. No evidence was found to support de novo synthesis or precursor reactions forming new PCDD/Fs. In addition, 94–100% of all the PTEs analyzed were retained in the post-smouldered material. These results indicate that only minimal emissions treatment for PTEs, PCDD/Fs, and VOCs may be necessary for future sewage sludge smouldering systems. These low emissions risks combined with its unique ability to handle high moisture content waste, indicate that smouldering has significant potential as a valuable waste management technique.
Fidelity with self-transcendent values is hailed as a hallmark of mature and magnanimous character by classic psychological and philosophical theories. Dozens of contemporary experiments inspired by self-affirmation theory have also found that when people are under threat, focus on self-transcendent values can confer magnanimity by improving psychological buoyancy (less anxious and more courageous, determined, and effective) and decreasing belligerence (less defensive, extreme, and hostile). The present research was guided by the postulate that both aspects of magnanimity—its buoyancy and its freedom from belligerence—arise from the approach motivated states that self-transcendent foci can inspire. Experimental manipulations of self-transcendent foci (values, spirituality, compassion) heightened state approach motivation as assessed by electroencephalography (Study 1, n = 187) and self-report (Study 2, n = 490). Further, even though the heightened approach motivation was transient, it mediated a longer-lasting freedom from moral (Study 1) and religious (Study 2) belligerence. Importantly, self-transcendent-focus effects on approach motivation and belligerence occurred only among participants with high trait meaning search scores. Results support an interpretation of meaningful values and spiritual ideals as self-transcendent priorities that operate according to basic motivational mechanics of abstract-goal pursuit. The transient, approach-motivated state aroused by transcendence-focus causes longer lasting relief from preoccupation with threat, leaving people feeling buoyant and generous. Relevance of results for self-affirmation theory and the psychology of spirituality are discussed.
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