Reducing variability in along-tract analysis with diffusion profile realignment

Diffusion weighted MRI (dMRI) provides a non invasive virtual reconstruction of the brain's white matter structures through tractography. Analyzing dMRI measures along the trajectory of white matter bundles can provide a more specific investigation than considering a region of interest or tract-averaged measurements. However, performing group analyses with this along-tract strategy requires correspondence between points of tract pathways across subjects. This is usually achieved by creating a new common space where the representative streamlines from every subject are resampled to the same number of points. If the underlying anatomy of some subjects was altered due to, e.g. disease or developmental changes, such information might be lost by resampling to a fixed number of points. In this work, we propose to address the issue of possible misalignment, which might be present even after resampling, by realigning the representative streamline of each subject in this 1D space with a new method, coined diffusion profile realignment (DPR). Experiments on synthetic datasets show that DPR reduces the coefficient of variation for the mean diffusivity, fractional anisotropy and apparent fiber density when compared to the unaligned case. Using 100 in vivo datasets from the HCP, we simulated changes in mean diffusivity, fractional anisotropy and apparent fiber density. Pairwise Student's t-tests between these altered subjects and the original subjects indicate that regional changes are identified after realignment with the DPR algorithm, while preserving differences previously detected in the unaligned case. This new correction strategy contributes to revealing effects of interest which might be hidden by misalignment and has the potential to improve the specificity in longitudinal population studies beyond the traditional region of interest based analysis and along-tract analysis workflows.Comment: v4: peer-reviewed round 2 v3 : deleted some old text from before peer-review which was mistakenly included v2 : peer-reviewed version v1: preprint as submitted to journal NeuroImag

High-Fidelity and Ultrafast Initialization of a Hole Spin Bound to a Te Isoelectronic Center in ZnS

We demonstrate the optical initialization of a hole-spin qubit bound to an isoelectronic center (IC) formed by a pair of Te impurities in ZnSe, an impurity/host system providing high optical homogeneity, large electric dipole moments, and long coherence times. The initialization scheme is based on the spin-preserving tunneling of a resonantly excited donor-bound exciton to a positively charged Te IC, thus forming a positive trion. The radiative decay of the trion within less than 50 ps leaves a heavy hole in a well-defined polarization-controlled spin state. The initialization fidelity exceeds 98:5 % for an initialization time of less than 150 ps.Comment: 5 pages, 3 figures, 1 supplemental information sectio

La représentation contemporaine du corps comme allégorie de la société

La conception du corps individuel peut être considérée comme une allégorie du corps social. C’est à ce titre que nous essaierons de démontrer que les idées qui ont cours sur le corps individuel reflètent celles qui ont cours à propos de la société en général. De cette manière, le corps apparaît comme un site de représentation du social. Dans cette perspective, nous défendrons l’hypothèse que la dématérialisation partielle du corps semble indiquer une véritable métamorphose de la dynamique sociétale contemporaine, et en même temps la symbolisation d’une nouvelle représentation sociétale du corps. Au coeur de cette problématique, nous considérerons le double processus de la naturalisation de la culture et de la culturalisation de la nature.The conception of the individual body can be seen as an allegory of the social body. In this article, we seek to demonstrate the parallels between ideas about the individual body and that of society in general, such that the body appears as a site for representing the social. Our hypothesis is one of a partial dematerialisation of the body that seems to indicate a real metamorphosis of the contemporary social dynamic and at the same time symbolises a new societal representation of the body. The heart of the question is a double process of naturalisation of culture and culturalisation of nature

Mentor functions for novice entrepreneurs

In the past few years, we have witnessed the birth of new mentoring programs, which consist in twining a novice entrepreneur with an experienced entrepreneur (also known as business mentoring). The literature on mentoring in large organization (where the protégé is an employee in the hierarchy) highlights that the mentor exerts three main categories of functions: psychological, career-related, and role model. This research aims to explore and to validate mentor functions for novice entrepreneurs. At first, a qualitative analysis based on focus groups including 51 mentees and 8 mentors was carried out. The theoretical proposal was then validated by a group of three experts in business mentoring. Finally, confirmatory factor analyses using LISREL were carried out on a sample of 360 mentees taking part in the mentoring program of the Fondation de l'entrepreneurship network, an organization which has twined more than 3500 novice entrepreneurs since the year 2000. The analyses confirm four psychological functions (reflector, reassurance, motivation, and confidant), four entrepreneurial career-related functions (integration, information support, confrontation, and guide) and a role model function. These results are useful to raise the awareness of volunteer mentors about functions they may likely exert when they are twined with novice entrepreneurs. © 2011 by the DreamCatchers Group, LLC, Arden NC, USA

Issue Salience and Ownership in the 2019 and 2021 Canadian Federal Elections

This report uses the 2019 and 2021 Canadian Election Study (CES) to explore how political issues and social cleavages are perceived by the electorate in the 2019 and 2021 federal elections. We focus more specifically on three dimensions: first, what issues were most important in electors’ minds (which we refer to as issue salience); second, which parties were seen as best able to handle various issues (which we refer to as issue ownership by parties); and finally, the social bases of party perceptions

A mixed methods portrait of the perceived benefits of unaccompanied ensemble singing on the development of the musical skills of undergraduate students

Thesis (D.M.A.)--Boston UniversityThe purpose of this investigation was to establish an understanding of the role that a cappella ensemble singing plays in the musical development of undergraduate ensemble singers based on the perspective of students, music teachers of three to five years experience, and faculty directors from four-year colleges and universities geographically located within the American Choral Directors Association (ACDA) Eastern Division, including the six New England states plus Delaware, Maryland, New Jersey, New York, and Pennsylvania. Research questions asked: In what ways is a cappella ensemble singing perceived to contribute to the musical development of college student musicians? Are there measureable differences in the perceived benefits of traditional and contemporary genres of a cappella ensemble singing between undergraduate students and faculty directors? Findings suggested that benefit exists in both traditional and contemporary a cappella ensemble singing. Descriptive research was employed in an exploratory, mixed-methods design as described by Creswell and Plano (2007). Phase one consisted of 18 face-to-face, open-ended, semi-structured interviews, five observations, and three student focus-groups. Broad themes emerged, including ensemble experience, genre, hearing and precision, personal attributes, promotion and support, vocal technique, reflecting increased proficiency in intonation, sight singing, tonal memory, rhythmic precision, musical expressivity, vocal range and flexibility, and increased confidence and sense of responsibility. A Web-based survey, consisting of questions informed by the qualitative research, comprised the second phase, comparing the perceptions of students (n = 59) and faculty directors (n = 11) on the benefits of both traditional and contemporary a cappella ensemble singing. Mann-Whitney U and Wilcoxon Signed Ranks Tests were employed to test ordinal data for statistical differences between and within groups relative to traditional and contemporary a cappella ensemble singing. Statistical differences (p < .05) were found between the responses of students and faculty directors in musical expressivity, vocal range and flexibility (contemporary), and in attitudes regarding the importance of contemporary a cappella ensemble singing for music education students. Statistical differences emerged among student responses regarding intonation, sight singing, musical expressivity, rhythmic precision, independence, level of challenge, commitment, and among faculty directors regarding the importance of the contemporary genre for music education majors