Fiber-Flux Diffusion Density for White Matter Tracts Analysis: Application to Mild Anomalies Localization in Contact Sports Players

We present the concept of fiber-flux density for locally quantifying white matter (WM) fiber bundles. By combining scalar diffusivity measures (e.g., fractional anisotropy) with fiber-flux measurements, we define new local descriptors called Fiber-Flux Diffusion Density (FFDD) vectors. Applying each descriptor throughout fiber bundles allows along-tract coupling of a specific diffusion measure with geometrical properties, such as fiber orientation and coherence. A key step in the proposed framework is the construction of an FFDD dissimilarity measure for sub-voxel alignment of fiber bundles, based on the fast marching method (FMM). The obtained aligned WM tract-profiles enable meaningful inter-subject comparisons and group-wise statistical analysis. We demonstrate our method using two different datasets of contact sports players. Along-tract pairwise comparison as well as group-wise analysis, with respect to non-player healthy controls, reveal significant and spatially-consistent FFDD anomalies. Comparing our method with along-tract FA analysis shows improved sensitivity to subtle structural anomalies in football players over standard FA measurements

An Investigation Of The Erosion In New Major Innovation Characteristics Over Time

A recent study by ODonnell and Sauer (2008) indicated, that over time, the benefit of launching new majors to reduce freshman attrition dissipated. In 2004, new majors had a significant effect on reducing attrition. By 2007, however, these same new majors were no longer significant predictors of attrition. What happened between 2004 and 2007 to cause this erosion in the affect of new majors on attrition? In this study, we examine the differences in perceptions of the innovative characteristics in an effort to explain why this erosion might have occurred. Results of a two-way between subjects ANOVA reveals that new majors began to be perceived as similar to old majors along certain dimensions of innovative characteristics. In particular, differences in the prospects of getting a better job, the perception that the new major was easier, hearing from others that new majors offered better job prospects and that employers preferred new majors, and that new majors were less compatible with student needs and goals, all disappeared by 2007. Nevertheless, new majors were still perceived as requiring more prerequisites, being more likely to require an extra course, and as not being offered at other area colleges and universities relative to old majors. This article discusses the impact and consequences of these findings and proposes future research to be pursued

First principles calculation of uniaxial magnetic anisotropy and magnetostriction in strained CMR films

We performed first - principles relativistic full-potential linearized augmented plane wave calculations for strained tetragonal ferromagnetic La(Ba)MnO$_3$ with an assumed experimental structure of thin strained tetragonal La$_{0.67}$Ca$_{0.33}$MnO$_3$ (LCMO) films grown on SrTiO$_3$[001] and LaAlO$_3$[001] substrates. The calculated uniaxial magnetic anisotropy energy (MAE) values, are in good quantitative agreement with experiment for LCMO films on SrTiO$_3$ substrate. We also analyze the applicability of linear magnetoelastic theory for describing the stain dependence of MAE, and estimate magnetostriction coefficient $\lambda_{001}$.Comment: Talk given at APS99 Meeting, Atlanta, 199

A “Novel” Approach to the Design of an IS Management Course

We report on the design and implementation of an unusual course in Information Systems (IS) management built around an extended case series: a fictitious but reality-based story about the trials and tribulations of a newly appointed but not-technically-trained Chief Information Officer (CIO) in his first year on the job. Together the cases constitute a true-to-life “novel” about IS management (published, in fact, as a novel, as well as individual cases). Four principles guided development of the series and its associated pedagogy: 1) Emphasis on integrative, soft-skill, and business-oriented aspects of IS, independent of underlying technologies; 2) Student derivation and ongoing refinement of cumulative theoretical frameworks arrived at via in-class discussion; 3) Identification of a set of core issues vital to practice that collectively approximate IS management as a business discipline; and 4) Design for student engagement, in particular by basing the case “story” on the monomyth, a literary pattern common to important narratives around the world. A supporting website facilitates sharing of teaching materials and experiences by faculty using the case series. We report results from using this curriculum with undergraduate and graduate students in two universities in different countries, and with executives at a multinational corporation and in an executive program at Harvard Business School. Our results suggest that a “novel-based” approach holds considerable promise for use at undergraduate, graduate, and executive levels, and that it might have advantages in addressing the so-called “enrollment crisis” in IS education, especially with the generation of “digital natives” who have come of age in an environment crowded with engaging approaches to communication and entertainment that compete for their attention

Diurnal Refractive Error Fluctuations in Diabetic and Control Subjects

Purpose: Refractive error has been shown to fluctuate in poorly controlled diabetic patients. The purpose of this study was to measure acute diurnal fluctuations in refractive error and blood glucose levels (BGLs) in diabetic and control subjects. Methods: Twenty-one type 2 diabetic subjects (age 56 ± 11 years), 20 type 1 diabetic subjects (age 38 ± 15 years) and 20 non-diabetic controls (age 49 ± 23 years) took part in the study. Refractive error was measured with an OPD ARK-10000 autorefractometer (Nidek) and BGLs were measured using a finger stick test (Hemocue). All measurements were taken six times during the day, between 8AM and 8PM at approximately twohourly intervals. Using power vector analysis the variability in refractive error was mapped against time of day and related to BGLs, HbA1c, diabetic status and duration of disease. Results: Refractive error was similar between groups (p=0.96) and did not fluctuate significantly during the day in any of the three groups (ANOVA p>0.05). The mean ± SD values for BGLs during the day were 10.4 ± 4.40mM/l in DM type 2, 10.3 ± 5.30mM/l in DM type 1, and 5.4 ± 1.04mM/l in control subjects. BGLs changed significantly during the day and between groups (ANOVA p0.05). Multiple regression analysis showed that neither BGLs, HbA1c, diabetic status, nor duration of disease had a significant effect on diurnal refractive error measurements. (p>0.05). Conclusions: Diurnal changes in BGLs do not result in significant acute refractive error fluctuations in diabetic patients, as measured with an autorefractometer. CR: C. O’Donnell, None; H. Workman, None; S.L. Hosking, None; B. Huntjens, None. Support: Supported by a PhD studentship from Lein Applied Diagnostics Ltd

Priming reveals attentional modulation of human motion sensitivity

AbstractAlthough recent fMRI and single unit recording studies have shown that attention modulates neural activity in motion sensitive areas of extrastriate cortex, these approaches cannot reveal qualitative or quantitative effects of attention on perception of motion. To investigate this, we asked observers to select one of two orthogonal directions in a brief, transparent dot display (prime) and then measured their sensitivity to global directional motion in a second uni-directional dot display (probe) presented a short time later. When probe direction matched the attended prime direction, sensitivity was degraded. But, when probe direction matched the ignored prime direction, sensitivity was enhanced, even though both components were of equal physical strength. Sensitivity was unchanged for directions opposite to either previously seen direction. Neither sensory adaptation nor opponent direction mechanisms can account for these data. Rather, processes initiated by visual selection must underlie these dramatic changes in motion sensitivity

Neutrinoless Double Beta Decay and CP Violation

We study the relation between the Majorana neutrino mass matrices and the neutrinoless double beta decay when CP is not conserved. We give an explicit form of the decay rate in terms of a rephasing invariant quantity and demonstrate that in the presence of CP violation it is impossible to have vanishing neutrinoless double beta decay in the case of two neutrino generations (or when the third generation leptons do not mix with other leptons and hence decouple).Comment: 9 pages, UTPT-93-1