We investigate the pulse evolution and energy conservation condition at the temporal boundary under third-order dispersion. When the fundamental soliton crosses the temporal boundary and forms two reflected pulses and one transmitted pulse, the power of the transmitted pulse first increases and then decreases as the incident spectrum shifts toward the blue side. If the transmitted spectrum lies in the anomalous group-velocity dispersion region, second-order soliton is formed and dispersive wave is radiated. We present a modified phase-matching condition to predict the resonance frequencies. The predicted results are in good agreement with the results obtained by numerically solving the nonlinear Schrödinger equation.
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http://dx.doi.org/10.1364/OE.507051 | DOI Listing |
Small Methods
January 2025
Center for Nanophase Materials Sciences, Oak Ridge National Laboratory, 1 Bethel Valley Road, Oak Ridge, TN, TN 37830, USA.
Understanding ferroelectric domain wall dynamics at the nanoscale across a broad range of timescales requires measuring domain wall position under different applied electric fields. The success of piezoresponse force microscopy (PFM) as a tool to apply local electric fields at different positions and imaging their changing position, together with the information obtained from associated switching spectroscopies has fueled numerous studies of the dynamics of ferroelectric domains to determine the impact of intrinsic parameters such as crystalline order, defects and pinning centers, as well as boundary conditions such as environment. However, the investigation of sub-coercive reversible domain wall vibrational modes requires the development of new tools that enable visualizing domain wall motion under varying applied fields with high temporal and spatial resolution while also accounting for spurious electrostatic effects.
View Article and Find Full Text PDFAlzheimers Dement
December 2024
Wake Forest University School of Medicine, Winston‐Salem, NC, USA
Background: Uniform manifold approximation and projection (UMAP) is a technique for dimension reduction and visualization of high‐dimensional (HD) data. Here, we apply UMAP to represent in two dimensions, data from members of the Wake Forest School of Medicine Alzheimer’s Disease Research Center (WFUSM‐ADRC) clinical cohort.
Methods: We examined baseline data from 542 WFUSM‐ADRC participants with mean age 70.
Alzheimers Dement
December 2024
Department of Clinical Sciences Lund, Lund University, Lund, Lund, Sweden
Background: The medial temporal lobe (MTL) is the epicenter of both primary and concomitant molecular pathologies in Alzheimer’s disease (AD). The intricate anatomy of the MTL has been the subject of extensive study over the past two centuries. However, current PET and MRI AD biomarkers use often crude parcellations of the MTL that have not been sufficiently validated vis‐à‐vis anatomical ground truth.
View Article and Find Full Text PDFBackground: Digital cognitive tools offer novel ways to detect early cognitive changes associated with preclinical Alzheimer’s disease (AD). A digital version of the maze test (dMaze) was recently developed using a digital pen (12 ms temporal precision) to uniquely capture the process of test completion, reflecting the thinking effort, potentially more sensitive to early cognitive deficits in preclinical AD. The sensitivity of these novel digital maze test variables—Wall Penetration Count and Speed Standard Deviation (Speed SD)—to detect early amyloid‐β burden was evaluated, hypothesizing that greater amyloid accumulation would be associated with greater variability of speed, and more wall penetration errors while completing the task, reflecting a greater thinking effort.
View Article and Find Full Text PDFAlzheimers Dement
December 2024
Department of Clinical Sciences Lund, Lund University, Lund, Lund, Sweden
Background: The medial temporal lobe (MTL) is the epicenter of both primary and concomitant molecular pathologies in Alzheimer’s disease (AD). The intricate anatomy of the MTL has been the subject of extensive study over the past two centuries. However, current PET and MRI AD biomarkers use often crude parcellations of the MTL that have not been sufficiently validated vis‐à‐vis anatomical ground truth.
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