Great earthquakes have occurred repeatedly along the Nankai Trough, but only for recent events are details known, such as rupture areas and time lags between paired events. It is meaningful for ...disaster prevention to consider in advance what kind of phenomena are likely after an earthquake that partially ruptures a seismogenic zone in this region. We constructed three-dimensional simulations to partially reproduce the spatial and temporal distribution of seismic or aseismic slip and the heterogeneous distribution of the slip-deficit rate beneath the seafloor on the plate boundary along the Nankai Trough. We found it necessary to assign spatial heterogeneity to two friction parameters, the effective normal stress and characteristic distance, based on a hierarchical asperity model. Our model produced many event pairs consisting of events east and west of Cape Shiono (Tokai/Tonankai and Nankai events, respectively), nearly all of them either simultaneous or separated by less than 3 years. The rupture areas of these event pairs were rich in variation, and even when the rupture areas were the same, the magnitudes and maximum displacements differed. The Tonankai earthquakes rarely occurred alone. Our model also simulated recurring long-term slow slip events in deeper parts of the seismogenic zone, and these events were caused by stress disturbance and heterogeneous stress distributions associated with non-ruptured portions of the seismogenic zone.
Graphical Abstract
The characteristics of shallow low‐frequency earthquakes (LFEs) are related to stress changes on the shallow plate boundary, which are important for understanding the megathrust earthquake cycle. The ...5 September 2004 off the Kii Peninsula earthquakes (MJMA = 7.1, 7.4) occurred near the Nankai trough subduction zone, off southwest Japan. Ocean bottom seismometer observations from 22 September to 30 November 2004 detected many shallow LFEs among the ordinary aftershocks. During the observation period, the frequency of shallow LFEs steadily decayed with the exception of episodic activities, which were very sensitive to stress changes caused by tides and the 23 October 2004 Niigata earthquake (MJMA = 6.8). We also confirmed correlations between shallow LFEs and shallow very low frequency earthquakes, which suggest that these slow events represent the same slip phenomenon. These findings will contribute to clarifying the impact of LFEs on megathrust earthquakes.
Key Points
We detected shallow low‐frequency earthquakes (LFEs) after the 2004 off Kii Peninsula earthquakes by using ocean bottom seismometers
Some shallow LFEs are associated with very low frequency earthquakes, which suggests both slow earthquakes represent the same phenomenon
Episodic shallow LFEs are stochastic yet sensitive to stress changes caused by both the 2004 Niigata earthquake and tidal effects
Purpose
Research has shown that a cemented mobile-bearing component has a favorable effect on the bone mineral density (BMD) of the distal femur at 2 years after total knee arthroplasty (TKA). This ...study was performed to determine whether the advantage on BMD of a cemented mobile-bearing TKA over a conventional cemented fixed-bearing TKA changes with time. This report is an update of a matched cohort study initiated in 2004 and for which the 2-year results have been published.
Methods
Twenty-eight knees that were treated with a fixed-bearing posterior stabilized (PS) prosthesis and 28 matched knees from a database of 76 knees that were treated with a mobile-bearing PS prosthesis in the same period were investigated. All knees underwent dual-energy X-ray absorptiometry (DEXA) scans around the femoral component preoperatively, 2 weeks postoperatively, 5 years postoperatively, and annually thereafter. Eighteen knees with a cemented mobile-bearing PS prosthesis and 20 knees with a cemented fixed-bearing PS prosthesis were investigated for more than 6 years. The mean follow-up period was 11 years.
Results
The range of motion, Knee Society Score, BMD of the lumbar spine, and follow-up period were not significantly different preoperatively and postoperatively in the two groups. In the fixed-bearing group, the BMD of the anterior part of the femoral condyle decreased postoperatively. In the mobile-bearing group, the BMD of the posterior part of the femoral condyle increased postoperatively. The postoperative change in the BMD at 5 years and the latest follow-up period was statistically significant in the two groups.
Conclusions
This DEXA study revealed that a cemented mobile-bearing component had a favorable effect on the BMD of the distal femur after TKA even at a mean of 11 years postoperatively.
Level of evidence
Therapeutic study, level II, prospective comparative study.
There have been lots of previous studies on fluency evaluation of spontaneous speech. However, most of them focus on lexical cues, and little emphasis is placed on how diverse acoustic features and ...deep end-to-end models contribute to improving the performance. In this paper, we describe multi-layer neural network to investigate not only lexical features extracted from transcription, but also consider utterance-level acoustic features from audio data. We also conduct the experiments to investigate the performance of end-to-end approaches with mel-spectrogram in this task. As the speech fluency evaluation task, we evaluate our proposed method in two binary classification tasks of fluent speech detection and disfluent speech detection. Speech data of around 10 seconds duration each with the annotation of the three classes of “fluent,” “neutral,” and “disfluent” is used for evaluation. According to the two way splits of those three classes, the task of fluent speech detection is defined as binary classification of fluent vs. neutral and disfluent, while that of disfluent speech detection is defined as binary classification of fluent and neutral vs. disfluent. We then conduct experiments with the purpose of comparative evaluation of multi-layer neural network with diverse features as well as end-to-end models. For the fluent speech detection, in the comparison of utterance-level disfluency-based, prosodic, and acoustic features with multi-layer neural network, disfluency-based and prosodic features only are better. More specifically, the performance improved a lot when removing all of the acoustic features from the full set of features, while the performance is damaged a lot if fillers related features are removed. Overall, however, the end-to-end Transformer+VGGNet model with mel-spectrogram achieves the best results. For the disfluent speech detection, the multi-layer neural network using disfluency-based, prosodic, and acoustic features without fillers achieves the best results. The end-to-end Transformer+VGGNet architecture also obtains high scores, whereas it is exceeded by the best results with the multi-layer neural network with significant difference. Thus, unlike in the fluent speech detection, disfluency-based and prosodic features other than fillers are still necessary in the disfluent speech detection.
Compensatory mechanisms, such as a decrease in thoracic spine kyphosis and posterior tilting or rotation of the pelvis, aim to achieve optimal alignment of the spine. However, the effect of muscle ...strength on these compensatory mechanisms has not been elucidated. This study aimed to investigate the impact of back muscle and lower extremity strength on compensatory mechanisms in elderly people. Overall, 409 community-dwelling elderly participants (164 men, 245 women) were included. Age, disc degeneration, and 2 or more vertebral fractures showed a significant increase of risk for sagittal vertical axis (SVA) deterioration. Conversely, stronger back, hip flexor, and knee extensor muscles reduced the risk for SVA deterioration. To investigate the association of each muscle's strength with compensatory mechanisms, 162 subjects with pelvic incidence-lumbar lordosis > 10° were selected. The linear regression model for thoracic kyphosis demonstrated a negative correlation with back muscle strength and positive correlation with vertebral fracture. The regression analysis for pelvic tilt demonstrated a positive correlation with knee extensor strength. Back, hip flexor, and knee extensor muscle strength were associated with sagittal spinal alignment. Back muscle strength was important for the decrease in thoracic kyphosis, and knee extensor strength was associated with pelvic tilt.
Understanding the mechanisms of nephron repair is critical for the design of new therapeutic approaches to treat kidney disease. The kidney can repair after even a severe insult, but whether adult ...stem or progenitor cells contribute to epithelial renewal after injury and the cellular origin of regenerating cells remain controversial. Using genetic fate-mapping techniques, we generated transgenic mice in which 94%-95% of tubular epithelial cells, but no interstitial cells, were labeled with either beta-galactosidase (lacZ) or red fluorescent protein (RFP). Two days after ischemia-reperfusion injury (IRI), 50.5% of outer medullary epithelial cells coexpress Ki67 and RFP, indicating that differentiated epithelial cells that survived injury undergo proliferative expansion. After repair was complete, 66.9% of epithelial cells had incorporated BrdU, compared to only 3.5% of cells in the uninjured kidney. Despite this extensive cell proliferation, no dilution of either cell-fate marker was observed after repair. These results indicate that regeneration by surviving tubular epithelial cells is the predominant mechanism of repair after ischemic tubular injury in the adult mammalian kidney.
In recent plant hormone research, there is an increased demand for a highly sensitive and comprehensive analytical approach to elucidate the hormonal signaling networks, functions, and dynamics. We ...have demonstrated the high sensitivity of a comprehensive and quantitative analytical method developed with nanoflow liquid chromatography–electrospray ionization-ion trap mass spectrometry (LC–ESI-IT-MS/MS) under multiple-reaction monitoring (MRM) in plant hormone profiling. Unlabeled and deuterium-labeled isotopomers of four classes of plant hormones and their derivatives, auxins, cytokinins (CK), abscisic acid (ABA), and gibberellins (GA), were analyzed by this method. The optimized nanoflow-LC–ESI-IT-MS/MS method showed ca. 5–10-fold greater sensitivity than capillary-LC–ESI-IT-MS/MS, and the detection limits (S/N
=
3) of several plant hormones were in the sub-fmol range. The results showed excellent linearity (
R
2 values of 0.9937–1.0000) and reproducibility of elution times (relative standard deviations, RSDs, <1.1%) and peak areas (RSDs, <10.7%) for all target compounds. Further, sample purification using Oasis HLB and Oasis MCX cartridges significantly decreased the ion-suppressing effects of biological matrix as compared to the purification using only Oasis HLB cartridge. The optimized nanoflow-LC–ESI-IT-MS/MS method was successfully used to analyze endogenous plant hormones in Arabidopsis and tobacco samples. The samples used in this analysis were extracted from only 17 tobacco dry seeds (1
mg DW), indicating that the efficiency of analysis of endogenous plant hormones strongly depends on the detection sensitivity of the method. Our analytical approach will be useful for in-depth studies on complex plant hormonal metabolism.
Along the Nankai Trough subduction zone, southwest Japan, short-term slow slip events (SSEs) are commonly detected in strain and tilt records. These observational data have been used in rectangular ...fault models with uniform slip to analyze SSEs; however, the assumption of uniform slip precludes the possibility of mapping the slip distribution in detail. We report here an inversion method, based on the joint use of strain and tilt data and evaluated in terms of the Akaike’s Bayesian information criterion (ABIC), to estimate the slip distributions of short-term SSEs on the plate interface. Tests of this method yield slip distributions with smaller errors than are possible with the use of strain or tilt data alone. This method provides detailed spatial slip distributions of short-term SSEs including probability estimates, enabling improved monitoring of their locations and amounts of slip.
The functional unit of the kidney is the nephron. During its organogenesis, the mammalian metanephric kidney generates thousands of nephrons over a protracted period of fetal life. All nephrons are ...derived from a population of self-renewing multi-potent progenitor cells, termed the cap mesenchyme. However, our understanding of the molecular and cellular mechanisms underlying nephron development is at an early stage. In order to identify factors involved in nephrogenesis, we performed a high-resolution, spatial profiling of a number of transcriptional regulators expressed within the cap mesenchyme and early developing nephron. Our results demonstrate novel, stereotypic, spatially defined cellular sub-domains within the cap mesenchyme, which may, in part, reflect induction of nephron precursors. These results suggest a hitherto unappreciated complexity of cell states that accompany the assembly of the metanephric kidney, likely reflecting diverse regulatory actions such as the maintenance and induction of nephron progenitors.
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