Combining Contrast Invariant L1 Data Fidelities with Nonlinear Spectral Image Decomposition

This paper focuses on multi-scale approaches for variational methods and corresponding gradient flows. Recently, for convex regularization functionals such as total variation, new theory and algorithms for nonlinear eigenvalue problems via nonlinear spectral decompositions have been developed. Those methods open new directions for advanced image filtering. However, for an effective use in image segmentation and shape decomposition, a clear interpretation of the spectral response regarding size and intensity scales is needed but lacking in current approaches. In this context, $L^1$ data fidelities are particularly helpful due to their interesting multi-scale properties such as contrast invariance. Hence, the novelty of this work is the combination of $L^1$-based multi-scale methods with nonlinear spectral decompositions. We compare $L^1$ with $L^2$ scale-space methods in view of spectral image representation and decomposition. We show that the contrast invariant multi-scale behavior of $L^1-TV$ promotes sparsity in the spectral response providing more informative decompositions. We provide a numerical method and analyze synthetic and biomedical images at which decomposition leads to improved segmentation.Comment: 13 pages, 7 figures, conference SSVM 201

Individual heat map assessments demonstrate vestronidase alfa treatment response in a highly heterogeneous mucopolysaccharidosis VII study population.

Mucopolysaccharidosis (MPS) VII is an ultra-rare, progressively debilitating, life-threatening lysosomal disease caused by deficiency of the enzyme, β-glucuronidase. Vestronidase alfa is an approved enzyme replacement therapy for MPS VII. UX003-CL301 was a phase 3, randomized, placebo-controlled, blind-start study examining the efficacy and safety of vestronidase alfa 4 mg/kg intravenously administered every 2 weeks to 12 patients with MPS VII. Due to the rarity of disease, broad eligibility criteria resulted in a highly heterogeneous population with variable symptoms. For an integrated view of the diverse data, the changes from baseline (or randomization for the placebo period) in clinical endpoints were grouped into three functional domains (mobility, fatigue, and fine motor + self-care) and analyzed post-hoc as subject-level heat maps. Mobility assessments included the 6-minute walk test, 3-minute stair climb test, Bruininks-Oseretsky test (BOT-2) gross motor function subtests, and patient-reported outcome assessments (PROs) related to movement, pain, and ambulation. Fatigue assessments included the Pediatric Quality of Life Multidimensional Fatigue Scale and other fatigue-related PROs. Fine motor + self-care assessments included BOT-2 fine motor function subtests and PROs for eating, dressing, hygiene, and caregiver assistance. Most subjects showed improvement in at least one domain. Two subjects improved in two or more domains and two subjects did not show clear improvement in any domain. Both severely and mildly affected subjects improved with vestronidase alfa in clinical assessments, PRO results, or both. Heat map analysis demonstrates how subjects responded to treatment across multiple domains, providing a useful visual tool for studying rare diseases with variable symptoms

Low frequency measurements of synchrotron absorbing HII regions and modeling of observed synchrotron emissivity

Cosmic rays (CRs) and magnetic fields are dynamically important components in the Galaxy, and their energy densities are comparable to that of the turbulent interstellar gas. The interaction of CRs and Galactic magnetic fields produces synchrotron radiation clearly visible in the radio regime. Detailed measurements of synchrotron radiation averaged over the line-of-sight (LOS), so-called synchrotron emissivities, can be used as a tracer of the CR density and Galactic magnetic field (GMF) strength. Our aim is to model the synchrotron emissivity in the Milky Way using a 3 dimensional dataset instead of LOS-integrated intensity maps on the sky. Using absorbed HII regions we can measure the synchrotron emissivity over a part of the LOS through the Galaxy, changing from a 2 dimensional to a 3 dimensional view. Performing these measurements on a large scale is one of the new applications of the window opened by current low frequency arrays. Using various simple axisymmetric emissivity models and a number of GMF-based emissivity models we can simulate the synchrotron emissivities and compare them to the observed values in the catalog. We present a catalog of low-frequency absorption measurements of HII regions, their distances and electron temperatures, compiled from literature. These data show that the axisymmetric emissivity models are not complex enough, but the GMF-based emissivity models deliver a reasonable fit. These models suggest that the fit can be improved by either an enhanced synchrotron emissivity in the outer reaches of the Milky Way, or an emissivity drop near the Galactic center. State-of-the-art GMF models plus a constant CR density model cannot explain low-frequency absorption measurements, but the fits improved with slight (ad-hoc) adaptations. It is clear that more detailed models are needed, but the current results are very promising.Comment: 14 pages, 9 figures, accepted for publication in A&

Vision for mobile robot localization in urban environments

This paper addresses the problem of mobile robot localization in urban environments. Typically, GPS is the preferred sensor for outdoor operation. However, using GPS-only localization methods leads to significant performance degradation in urban areas where tall nearby structures obstruct the clear view of the satellites. In our work, we use vision-based techniques to supplement GPS and odometry and provide accurate localization. The vision system identifies prominent linear features in the scene and matches them with a reduced model of nearby buildings, yielding improved pose estimation of the robot

INTEGRAL IBIS/ISGRI energy calibration in OSA 10

We present the new energy calibration of the ISGRI detector onboard INTEGRAL, that has been implemented in the Offline Scientific Analysis (OSA) version 10. With the previous OSA 9 version, a clear departure from stability of both W and 22Na background lines was observed after MJD 54307 (revolution ~583). To solve this problem, the energy correction in OSA 10 uses: 1) a new description for the gain depending on the time and the pulse rise time, 2) an improved temperature correction per module, and 3) a varying shape of the low threshold, corrected for the change in energy resolution. With OSA 10, both background lines show a remarkably stable behavior with a relative energy variation below 1% around the nominal position (>6% in OSA 9), and the energy reconstruction at low energies is more stable compared to previous OSA versions. We extracted Crab light curves with ISGRI in different energy bands using all available data since the beginning of the mission, and found a very good agreement with the currently operational hard X-ray instruments Swift/BAT and Fermi/GBM.Comment: Accepted for publication in proceedings of "An INTEGRAL view of the high-energy sky (the first 10 years)" the 9th INTEGRAL Workshop, October 15-19, 2012, Paris, France, in Proceedings of Science (INTEGRAL 2012), Eds. A. Goldwurm, F. Lebrun and C. Winkler, (http://pos.sissa.it/cgi-bin/reader/conf.cgi?confid=176), id 142; 6 pages, 6 figure

Teacher CPD across borders: Reflections on how a study tour to England helped to change practice and praxis among Jamaican teachers

This article is available open access from the publisher’s website through the link below. Copyright © 2014 Pak Publishing Group.The professional development of teachers and school leaders is an important factor in improving the overall quality and effectiveness of schools. Teachers and Principals who are well trained and who have exposure to different educational systems are in a position to draw on their experiences of other systems to improve outcomes for their classrooms, staffrooms and institutions as a whole. Reflecting on our own experiences of organising and delivering a Study Tour, we also present the experiences of Jamaican public educators on a recent Study Tour to England. From their feedback, it is clear that this experiential approach to capacity building has gone some way in stimulating participants’ thinking as regards their practice and how this can be improved, underpinned by Hargreaves and Fullan’s (2012) notion of reconceptualising professional capital and Mintzberg (2004) view of global mindsets

Investment in education: some lessons from the international evidence for the Baltic states

The international empirical evidence on the economics of education reveals one central insight and two puzzles, which are all relevant for the case of the Baltic States. The central insight is that social rates of return to education tend to be higher than the social opportunity costs of capital, except for the case of higher education. Based on this microeconomic evidence, the case for public investment in education is well founded, especially at the primary and the secondary levels. The first puzzle is that at the macroeconomic level, the presumed positive link between increases in educational attainment and income growth is difficult to detect. One reason is that a high rate of absorption of well-educated workers by the government sector, typical for many developing countries, is likely to reduce the long-run growth rate. The second puzzle is that there is no clear link between higher spending on educational inputs and higher educational output in the form of improved performance of pupils. As it seems, higher spending on education is not sufficient to improve performance as long as inefficiencies in the schooling system remain. For the Baltic States, three basic lessons emerge from the international evidence: First, public investment in higher education does not show up as a top priority from a social point of view; second, the macroeconomic return to education could turn out to be low if better educated workers predominantly end up in the relatively large government sectors typical for the Baltic States. Third, the productivity of schooling could probably be improved, for instance by a different allocation of resources within the education sector. Most likely, such an outcome would require a fundamental reform of the schooling system itself, not only in the Baltic States. --