Search results for "T2* map"
showing 10 items of 90 documents
Affine Invariant Multivariate Sign and Rank Tests and Corresponding Estimates: a Review
1999
The paper reviews recent contributions to the statistical inference methods, tests and estimates, based on the generalized median of Oja. Multivariate analogues of sign and rank concepts, affine invariant one-sample and two-sample sign tests and rank tests, affine equivariant median and Hodges–Lehmann-type estimates are reviewed and discussed. Some comparisons are made to other generalizations. The theory is illustrated by two examples.
Influence functions and efficiencies of the canonical correlation and vector estimates based on scatter and shape matrices
2006
In this paper, the influence functions and limiting distributions of the canonical correlations and coefficients based on affine equivariant scatter matrices are developed for elliptically symmetric distributions. General formulas for limiting variances and covariances of the canonical correlations and canonical vectors based on scatter matrices are obtained. Also the use of the so-called shape matrices in canonical analysis is investigated. The scatter and shape matrices based on the affine equivariant Sign Covariance Matrix as well as the Tyler's shape matrix serve as examples. Their finite sample and limiting efficiencies are compared to those of the Minimum Covariance Determinant estima…
The importance of level stratification for quantitative MR studies of lumbar intervertebral discs : a cross-sectional analysis in 101 healthy adults
2019
Purpose: To investigate whether quantitative T2-times depend on lumbar intervertebral disc (IVD) level. Methods: The lumbar spine (Th12/L1–L5/S1) of 101 participants (53.5% female, 30.0[± 3.6]years, 173.5[± 9.6]cm and 69.9[± 13.4]kg), without history of back pain, was examined on a 3T scanner with sagittal T2-mapping. All IVDs were stratified according to Pfirrmann grade and lumbar level, with mean T2-time determined for the entire IVD volume and in five subregions of interests. Results: Significant level-dependent T2-time differences were detected, both for the entire IVD volume and its subregions. For the entire IVD volume, Pfirrmann grade 2 IVDs displayed 9–18% higher T2-times in Th12/L1…
Teachers’ beliefs about gamification and competencies development: A concept mapping approach
2020
Despite an increasing academic attention towards both gamification and competencies-based education, little is known about Higher Education teachers’ beliefs regarding the use of gamification to develop students’ competencies. To fill this research gap, concept mapping was used to cluster teachers’ beliefs in 4 dimensions regarding the use of gamification to develop students’ competencies. Our findings suggest that teachers believe that gamification encourages team working and oral communication skills. Moreover, critical thinking and social skills development were also found as some of the benefits that teachers believe the use of gamification can provide to the development of students’ co…
Human settlement dynamics and alluvial dynamics of the Rhine River during the Holocene: Geoarchaeology of the site of Oedenburg (Haut-Rhin, France).
2007
The relationship between alluvial dynamics and control parameters such as climate are well known and understood at plurimillennial and pluriannual time-scales. But it is not really the case at multicentennial and multidecennal time-scales compatible with human society settlement time-scales. In a present and near future context, when human settlement may be affected by strong climatic variation, alluvial dynamics understanding is however a major centre of attention to the development of efficient models. To approach this scale-related question, a segment of the Upper Rhine River presenting both anastomosed and braided was investigated. This area also gives us the opportunity to study settle…
Transformation of the Software Testing Glossary into a Browsable Concept Map
2014
Authors propose a transformation method of the glossary “Standard glossary of terms used in Software Testing” created by ISTQB document into a basic concept map. By applying natural language processing techniques and analyzing the discovered relations between concepts the most essential aspects of the software testing domain are elicited and integrated. As the result a browsable concept map is created. Browsable concept map can be used as a learning support tool.
RNACache: Fast Mapping of RNA-Seq Reads to Transcriptomes Using MinHashing
2021
The alignment of reads to a transcriptome is an important initial step in a variety of bioinformatics RNA-seq pipelines. As traditional alignment-based tools suffer from high runtimes, alternative, alignment-free methods have recently gained increasing importance. We present a novel approach to the detection of local similarities between transcriptomes and RNA-seq reads based on context-aware minhashing. We introduce RNACache, a three-step processing pipeline consisting of minhashing of k-mers, match-based (online) filtering, and coverage-based filtering in order to identify truly expressed transcript isoforms. Our performance evaluation shows that RNACache produces transcriptomic mappings …
On the classification of CAT(0) structures for the 4-string braid group
2005
This paper is concerned with the class of so-called CAT(0) groups, namely, those groups that admit a geometric (i.e., properly discontinuous, co-compact, and isometric) action on some CAT(0) space. More precisely, we are interested in knowing to what extent it is feasible to classify the geometric CAT(0) actions of a given group (up to, say, equivariant homothety of the space). A notable example of such a classification is the flat torus theorem, which implies that the minimal geometric CAT(0) actions of the free abelian group Z (n ≥ 1) are precisely the free actions by translations of Euclidean space E. Typically, however, a given group will have uncountably many nonequivalent actions, mak…
Acquisition of Higher Order Knowledge by a Dynamic Modeling Environment Based on the Educational Concept of Self-Regulated Learning
2013
I aim to show that learning with this modeling based Educational Learning System (ELS) can accomplish the target of achieving higher order knowledge. The ELS is a system consisting of internal and external elements. The external prerequisites consist of technical and physical elements and the internal ones are shaped by the students pre-knowledge and the instructors teaching competencies including his/her social, emotional, and disciplinary knowledge necessary for teaching. The ELS is based on a theoretical framework of different theories and models such as concept mapping, elaboration of mental models, cognitive tool-approach, and self-regulated learning (SRL). Different features for visua…
Les représentations spatiales de concepts scientifiques : inventaire et diversité
1994
The consultation of twelve journals (French and English language) that deal with science education, for the years 1991 to 1993, allowed us to summarize the use of spatial representations of scientific concepts in didactics research. Two main results were produced from this study : there has not been much work published with spatial representations, and what has been published is very heterogeneous. Analysis of this diversity does not always allow us to understand the authors’ objectives and obliges researchers in didactics to think about the nature and role of spatial representations in the construction of scientific knowledge.