7 research outputs found
Pressure-induced non-monotonic crossover of steady relaxation dynamics in a metallic glass
Relaxation dynamics, as a key to understand glass formation and glassy
properties, remains an elusive and challenging issue in condensed matter
physics. In this work, in situ high-pressure synchrotron high-energy x-ray
photon correlation spectroscopy has been developed to probe the atomic-scale
relaxation dynamics of a cerium-based metallic glass during compression.
Although the sample density continuously increases, the collective atomic
motion initially slows down as generally expected and then counter-intuitively
accelerates with further compression (density increase), showing an unusual
non-monotonic pressure-induced steady relaxation dynamics crossover at ~3 GPa.
Furthermore, by combining in situ high-pressure synchrotron x-ray diffraction,
the relaxation dynamics anomaly is evidenced to closely correlate with the
dramatic changes in local atomic structures during compression, rather than
monotonically scaling with either sample density or overall stress level. These
findings could provide new insight into relaxation dynamics and their
relationship with local atomic structures of glasses.Comment: 21 pages, 4 figure
Pressure-induced nonmonotonic cross-over of steady relaxation dynamics in a metallic glass
Relaxation dynamics, as a key to understand glass formation and glassy properties, remains an elusive and challenging issue in condensed matter physics. In this work, in situ high-pressure synchrotron high-energy X-ray photon correlation spectroscopy has been developed to probe the atomic-scale relaxation dynamics of a cerium-based metallic glass during compression. Although the sample density continuously increases, the collective atomic motion initially slows down as generally expected and then counterintuitively accelerates with further compression (density increase), showing an unusual nonmonotonic pressure-induced steady relaxation dynamics cross-over at ~3 GPa. Furthermore, by combining in situ high-pressure synchrotron X-ray diffraction, the relaxation dynamics anomaly is evidenced to closely correlate with the dramatic changes in local atomic structures during compression, rather than monotonically scaling with either sample density or overall stress level. These findings could provide insight into relaxation dynamics and their relationship with local atomic structures of glasses
Generalized fused group lasso regularized multi-task feature learning for predicting cognitive outcomes in Alzheimers disease
Nonlinearity-aware based dimensionality reduction and over-sampling for AD/MCI classification from MRI measures
Genome-wide association study of 107 phenotypes in Arabidopsis thaliana inbred lines
International audienceAlthough pioneered by human geneticists as a potential solution to the challenging problem of finding the genetic basis of common human diseases1,2, genome-wide association (GWA) studies have, owing to advances in genotyping and sequencing technology, become an obvious general approach for studying the genetics of natural variation and traits of agricultural importance. They are particularly useful when inbred lines are available, because once these lines have been genotyped they can be phenotyped multiple times, making it possible (as well as extremely cost effective) to study many different traits in many different environments, while replicating the phenotypic measurements to reduce environmental noise. Here we demonstrate the power of this approach by carrying out a GWA study of 107 phenotypes in Arabidopsis thaliana, a widely distributed, predominantly self-fertilizing model plant known to harbour considerable genetic variation for many adaptively important traits3. Our results are dramatically different from those of human GWA studies, in that we identify many common alleles of major effect, but they are also, in many cases, harder to interpret because confounding by complex genetics and population structure make it difficult to distinguish true associations from false. However, a-priori candidates are significantly over-represented among these associations as well, making many of them excellent candidates for follow-up experiments. Our study demonstrates the feasibility of GWA studies in A. thaliana and suggests that the approach will be appropriate for many other organisms