Nonlinear Drift Resonance Between Charged Particles and Ultralow Frequency Waves: Theory and Observations

In Earth’s inner magnetosphere, electromagnetic waves in the ultralow frequency (ULF) range play an important role in accelerating and diffusing charged particles via drift resonance. In conventional drift resonance theory, linearization is applied under the assumption of weak waveâ particle energy exchange so particle trajectories are unperturbed. For ULF waves with larger amplitudes and/or durations, however, the conventional theory becomes inaccurate since particle trajectories are strongly perturbed. Here we extend the drift resonance theory into a nonlinear regime, to formulate nonlinear trapping of particles in a waveâ carried potential well, and predict the corresponding observable signatures such as rolledâ up structures in particle energy spectrum. After considering how this manifests in particle data with finite energy resolution, we compare the predicted signatures with Van Allen Probes observations. Their good agreement provides the first observational evidence for the occurrence of nonlinear drift resonance, highlighting the importance of nonlinear effects in magnetospheric particle dynamics under ULF waves.Plain Language SummaryIn Earth’s Van Allen radiation belts, ultralow frequency (ULF) waves in the frequency range between 2 and 22 mHz play a crucial role in accelerating charged particles via a resonant process named drift resonance. When such a resonance occurs, a resonant particle observes a constant phase of the wave electric field, and it experiences a net energy excursion. In previous studies of drift resonance, a linearization approach is often applied with assumption of a weak waveâ particle energy exchange. In this study, we extend the linear theory into the nonlinear regime to formulate the particle behavior in the ULF wave field, and predict characteristic signatures of the nonlinear process observable from a virtual magnetospheric spacecraft. Such newly predicted signatures are found to agree with observations from the National Aeronautics and Space Administration’s Van Allen Probes, which provides the first identification of nonlinear drift resonance and highlights the importance of nonlinear effects in ULF waveâ particle interactions in the Van Allen radiation belts.Key PointsThe nonlinear theory of ULF waveâ particle drift resonance is developed to formulate the behavior of charged particles in ULF wave fieldSignatures of nonlinear drift resonance include rolledâ up structures and/or multiperiod oscillations in the particle energy spectrumIn situ observations of the newly predicted signatures validate the theory and provide a first identification of nonlinear drift resonancePeer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/146432/1/grl57916_am.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/146432/2/grl57916.pd

Cross-cultural validation of simplified Chinese version of spine functional index

Abstract Background No effective constructs were available in mainland China to assess the whole spine function. The SFI was developed to evaluate spinal function based on the concept of a single kinetic chain concept for whole spine. The SFI has been translated to Spanish and Turkish with accepted psychometric properties. It is imperative to introduce the SFI in mainland China and further to explore the measurement properties. Methods The English versions of the SFI was cross-culturally translated according to international guidelines. Measurement properties (content validity, construct validity and reliability) were tested in accordance with the COSMIN checklists. A total of 271 patients were included in this study, and 61 participants with neck pain and 64 participants with back pain paid a second visit three to seven days later. Confirmatory factor analysis (CFA) and principal factor analysis (PCA) were applied to test the factor structure. The Functional Rating Index (FRI), Neck Disability Index (NDI), Oswestry Disability Index (ODI), SF-12 and a Visual Analogue Scale (VAS) were employed to evaluate the construct validity. Cronbach’s alpha and an intra-class correlation coefficient (ICC) were calculated for internal consistency and reproducibility. Results The means score of SC-SFI was 63.60 in patients with spinal musculoskeletal disorders. A high response rate was acquired (265/271). No item was removed due to abnormal distribution or low item-total correlation. Results of CFA did not support that one-factor structure was in goodness of fit (CMIN/DF = 3.306, NNFI = 0.687, CFI = 0.756, GFI = 0.771 and RMSEA = 0.092). Yet, PCA suggested a one-factor structure was the best, accounting for 32% of the total variance. For structural validity, the SC-SFI correlated highly with the FRI, NDI, ODI, and PF, BP in SF-12 (r = 0.661, 0.610, 0.750, 0.709, 0.605, respectively). All the a priori hypotheses were verified. The Cronbach’s alpha for the SC-SFI was 0.91, and ICC was 0.96 (95% CI, 0.94–0.98). Bland-Altman plot also confirmed excellent test-retest reliability. Conclusions The SFI has been culturally adapted into SC-SFI with remarkable clinical acceptance, excellent internal consistency, reproducibility, and construct validity when applied to patients with spinal musculoskeletal disorders. The results of current study suggest that SC-SFI can be applied by physicians and researchers to measure whole-spine functional status in mainland China

Moderate Dose Irradiation Induces DNA Damage and Impairments of Barrier and Host Defense in Nasal Epithelial Cells in vitro

10.2147/JIR.S369385JournalofJOURNAL OF INFLAMMATION RESEARCH153661-367

Abnormal Expression of YAP Is Associated With Proliferation, Differentiation, Neutrophil Infiltration, and Adverse Outcome in Patients With Nasal Inverted Papilloma

10.3389/fcell.2021.625251FRONTIERS IN CELL AND DEVELOPMENTAL BIOLOGY

Statistically significant down regulated genes in the differentially.

<p>The red histogram in the figure represents the up regulated gene frequency, and the green histogram represents the down regulated gene frequency.</p

Annotation of unigenes in different databases.

<p>Annotation of unigenes in different databases.</p

Fertility-related differentially expressed genes (DEGs) clustering analysis heatmap of PM(4n×2n)-VS-OM(4n×2n).

<p>Fertility-related differentially expressed genes (DEGs) clustering analysis heatmap of PM(4n×2n)-VS-OM(4n×2n).</p