Neural correlates of (dys)fluent reading acquisition in typically reading and dyslexic children

Fluent reading requires both fast recognition of written text and an automatic link to the speech sounds that these letters represent. This thesis investigates brain mechanisms underlying both processes in nine year old typically reading and dyslexic children. By measuring electrical brain responses we showed that impairments in the neural coupling of letters and speech sounds relate to the severity of reading dysfluency in dyslexic children. Moreover, results of a dyslexia training study demonstrated that letter-speech sound training leads to a moderate improvement in reading fluency, and that the level of improvement relates to the severity of the underlying deficit

Stability of 1-D Excitons in Carbon Nanotubes under High Laser Excitations

Through ultrafast pump-probe spectroscopy with intense pump pulses and a wide continuum probe, we show that interband exciton peaks in single-walled carbon nanotubes (SWNTs) are extremely stable under high laser excitations. Estimates of the initial densities of excitons from the excitation conditions, combined with recent theoretical calculations of exciton Bohr radii for SWNTs, suggest that their positions do not change at all even near the Mott density. In addition, we found that the presence of lowest-subband excitons broadens all absorption peaks, including those in the second-subband range, which provides a consistent explanation for the complex spectral dependence of pump-probe signals reported for SWNTs.Comment: 4 pages, 4 figure

The economic impact of workplace wellness programmes in Canada

Background The economic benefits of workplace wellness programmes (WWPs) are commonly cited as a reason for employers to implement such programmes; however, there is limited evidence outside of the US context exploring their economic impact. US evidence is less relevant in countries such as Canada with universal publicly funded health systems because of the lower potential employer savings from WWPs. Aims To conduct a systematic review of the Canadian literature investigating the economic impact of WWPs from an employer perspective. The quality of that evidence was also assessed. Methods We reviewed literature which included analyses of four economic outcomes: return on investment calculations; cost-effectiveness or cost-benefit analyses; valuations of productivity, turnover, absenteeism and/or presenteeism costs; and valuations of health care utilization costs. We applied the British Medical Journal (BMJ) Economic Evaluation Working Party Checklist to evaluate the quality of this evidence. Results Eight studies met the inclusion criteria. Although the studies showed that WWPs generated economic benefits from an employer perspective (largely from productivity changes), none of the reviewed studies were in the high-quality category (i.e. fulfilled at least 75% of the checklist criteria) and most had severe methodological issues. Conclusions Though the Canadian literature pertaining to the economic impact of WWPs spans over three decades, robust evidence on this topic remains sparse. Future research should include a comparable control group, a time horizon of over a year, both direct and indirect costs, and researchers should apply analytical techniques that account for potential selection bias

Anomalous Aharonov--Bohm gap oscillations in carbon nanotubes

The gap oscillations caused by a magnetic flux penetrating a carbon nanotube represent one of the most spectacular observation of the Aharonov-Bohm effect at the nano--scale. Our understanding of this effect is, however, based on the assumption that the electrons are strictly confined on the tube surface, on trajectories that are not modified by curvature effects. Using an ab-initio approach based on Density Functional Theory we show that this assumption fails at the nano-scale inducing important corrections to the physics of the Aharonov-Bohm effect. Curvature effects and electronic density spilled out of the nanotube surface are shown to break the periodicity of the gap oscillations. We predict the key phenomenological features of this anomalous Aharonov-Bohm effect in semi-conductive and metallic tubes and the existence of a large metallic phase in the low flux regime of Multi-walled nanotubes, also suggesting possible experiments to validate our results.Comment: 7 figure

Cost-effectiveness of using a gene expression profiling test to aid in identifying the primary tumour in patients with cancer of unknown primary.

We aimed to investigate the cost-effectiveness of a 2000-gene-expression profiling (GEP) test to help identify the primary tumor site when clinicopathological diagnostic evaluation was inconclusive in patients with cancer of unknown primary (CUP). We built a decision-analytic-model to project the lifetime clinical and economic consequences of different clinical management strategies for CUP. The model was parameterized using follow-up data from the Manitoba Cancer Registry, cost data from Manitoba Health administrative databases and secondary sources. The 2000-GEP-based strategy compared to current clinical practice resulted in an incremental cost-effectiveness ratio (ICER) of $44,151 per quality-adjusted life years (QALY) gained. The total annual-budget impact was$36.2 million per year. A value-of-information analysis revealed that the expected value of perfect information about the test\u27s clinical impact was $4.2 million per year. The 2000-GEP test should be considered for adoption in CUP. Field evaluations of the test are associated with a large societal benefit.The Pharmacogenomics Journal advance online publication, 29 March 2016; doi:10.1038/tpj.2015.94

Orbital Kondo effect in carbon nanotubes

Progress in the fabrication of nanometer-scale electronic devices is opening new opportunities to uncover the deepest aspects of the Kondo effect, one of the paradigmatic phenomena in the physics of strongly correlated electrons. Artificial single-impurity Kondo systems have been realized in various nanostructures, including semiconductor quantum dots, carbon nanotubes and individual molecules. The Kondo effect is usually regarded as a spin-related phenomenon, namely the coherent exchange of the spin between a localized state and a Fermi sea of electrons. In principle, however, the role of the spin could be replaced by other degrees of freedom, such as an orbital quantum number. Here we demonstrate that the unique electronic structure of carbon nanotubes enables the observation of a purely orbital Kondo effect. We use a magnetic field to tune spin-polarized states into orbital degeneracy and conclude that the orbital quantum number is conserved during tunneling. When orbital and spin degeneracies are simultaneously present, we observe a strongly enhanced Kondo effect, with a multiple splitting of the Kondo resonance at finite field and predicted to obey a so-called SU(4) symmetry.Comment: 26 pages, including 4+2 figure

Simulation of an SEIR infectious disease model on the dynamic contact network of conference attendees

The spread of infectious diseases crucially depends on the pattern of contacts among individuals. Knowledge of these patterns is thus essential to inform models and computational efforts. Few empirical studies are however available that provide estimates of the number and duration of contacts among social groups. Moreover, their space and time resolution are limited, so that data is not explicit at the person-to-person level, and the dynamical aspect of the contacts is disregarded. Here, we want to assess the role of data-driven dynamic contact patterns among individuals, and in particular of their temporal aspects, in shaping the spread of a simulated epidemic in the population. We consider high resolution data of face-to-face interactions between the attendees of a conference, obtained from the deployment of an infrastructure based on Radio Frequency Identification (RFID) devices that assess mutual face-to-face proximity. The spread of epidemics along these interactions is simulated through an SEIR model, using both the dynamical network of contacts defined by the collected data, and two aggregated versions of such network, in order to assess the role of the data temporal aspects. We show that, on the timescales considered, an aggregated network taking into account the daily duration of contacts is a good approximation to the full resolution network, whereas a homogeneous representation which retains only the topology of the contact network fails in reproducing the size of the epidemic. These results have important implications in understanding the level of detail needed to correctly inform computational models for the study and management of real epidemics

Effect of Constant versus Variable Small-Group Facilitators on Student Basic Science Knowledge in an Enquiry-Based Dental Curriculum

doi: 10.1111/eje.12451Abstract Introduction The role of small-group facilitators is of pivotal importance for the success of curricula based on active learning. Disorganised tutorial processes and superficial study of the problem have been identified as main hindering factors for students? learning. The aim of this study was to evaluate the influence of consistency of facilitation on students? performance in knowledge-based, basic science assessments in a hybrid, enquiry-based (EBL) undergraduate dental curriculum. Materials and Methods This was a retrospective study of 519 year one and year two undergraduate dental students, enrolled at Peninsula Dental School between 2013 and 2018. Twice in each academic year, students sat a 60-item single-best-answer, multiple-choice examination. Percentage and Z-scores were compared between students whose EBL groups had the same facilitator throughout the academic year, and those whose EBL group was facilitated by different members of staff. All EBL facilitators were dentally qualified but with different levels of expertise in basic dental sciences, prior EBL facilitation, involvement in the curriculum design and university affiliation. Results No statistically significant difference was observed in the percentage or Z-scores of students whose EBL sessions were supported by consistent or variable facilitators in any of the 18 MCQ tests. Z-scores of year 1 students were more variable than for year 2 students. In addition, pairwise comparisons revealed no statistically significant differences in student Z-scores between any of the permanent facilitators? groups. Conclusions The results of our study may influence the design and delivery of enquiry-based curricula as well as human resources management by shifting the focus from maintaining facilitator consistency to ensuring comparable training and approaches across facilitators. This article is protected by copyright. All rights reserved

Effectiveness and Cost Effectiveness of Expanding Harm Reduction and Antiretroviral Therapy in a Mixed HIV Epidemic: A Modeling Analysis for Ukraine

A cost-effectiveness study by Sabina Alistar and colleagues evaluates the effectiveness and cost effectiveness of different levels of investment in methadone, ART, or both, in the mixed HIV epidemic in Ukraine