The sperm flagellum is a specialized type of motile cilium composed of a typical “9 + 2” axonemal structure with peri-axonemal structures, such as outer dense fibers (ODFs). This flagellar ...arrangement is crucial for sperm movement and fertilization. However, the association of axonemal integrity with ODFs remains poorly understood. Here, we demonstrate that mouse BBOF1 could interact with both MNS1, an axonemal component, and ODF2, an ODF protein, and is required for sperm flagellar axoneme maintenance and male fertility. BBOF1 is expressed exclusively in male germ cells from the pachytene stage onwards and is detected in sperm axoneme fraction. Spermatozoa derived from
Bbof1
-knockout mice exhibit a normal morphology, however, reduced motility due to the absence of certain microtubule doublets, resulting in the failure to fertilize mature oocytes. Furthermore, BBOF1 is found to interact with ODF2 and MNS1 and is also required for their stability. Our findings in mice suggest that
Bbof1
could also be essential for human sperm motility and male fertility, thus is a novel potential candidate gene for asthenozoospermia diagnosis.
The Earth's solid inner core (IC) is generally believed to rotate relative to the mantle, but the proposal remains controversial. Here we use seven waveform doublets in the South Sandwich Islands ...region with time lapses of 5.8–17.0 years that are recorded by two close stations in Kyrgyzstan with virtually the same epicentral distance. The fortuitous geometry allows precise measurements of the IC temporal changes and the underlying local structure at the same time. The remarkable observations in waveforms and spatial‐temporal measurements show unequivocally that the IC must have shifted (rotated) eastward in 1991–2010 and help determine accurately the average rotation rate as 0.127 ± 0.006°/yr at 95% confidence level during the time span.
Plain Language Summary
The Earth's solid inner core (IC) is surrounded by the liquid outer core and plays an important role in the deep earth dynamics, especially the generation of the Earth's magnetic field. It is still under debate whether the IC is rotating relative to the Earth's mantle and surface under the Earth's internal torques. Here we provided simple and direct observations that capture the relative rotation of the IC using a fortuitous combination of earthquakes and seismic stations. They allow us to determine the rotation rate as 0.13° per year (or 2.7 km per year at the equator of the IC boundary) faster than the mantle from 1991 to 2010.
Key Points
A fortuitous geometry of earthquakes and two close stations captured the rotation of the inner core (IC)
The temporal and spatial observations prove unequivocally that the IC must have shifted (rotated) eastward from 1991 to 2010
The rotation rate of the IC is determined accurately as 0.127 ± 0.006° per year during the time span
Neurofibromatosis type 1 (NF1) belongs to RASopathies, a group of syndromes caused by germline mutations in Ras/MAPK pathway genes. Most NF1 patients exhibit single inactivating pathogenic variants ...within the NF1 gene. We performed extensive genetic analyses in two NF1 families disclosing the first two cases of double de novo monoallelic NF1 variants. Both index patients described in this study had classical NF1. Probands were born from fathers in their late 30s and presented closely spaced double mutations (<100 bp) in NF1 regions showing an excess of somatic mutations. Closely spaced multiple mutations have been reported in RAS/MAPK signaling genes but never in NF1. Mutagenesis is a quasi‐random process in humans, therefore two causative variants in the same gene, moreover in the same allele are exceptional. Here, we discuss possible mechanisms for this ultrarare event. Our findings confirm the possibility of a higher risk of concurrent de novo variants in NF1.
Great earthquakes (having seismic magnitudes of at least 8) usually involve abrupt sliding of rock masses at a boundary between tectonic plates. Such interplate ruptures produce dynamic and static ...stress changes that can activate nearby intraplate aftershocks, as is commonly observed in the trench-slope region seaward of a great subduction zone thrust event. The earthquake sequence addressed here involves a rare instance in which a great trench-slope intraplate earthquake triggered extensive interplate faulting, reversing the typical pattern and broadly expanding the seismic and tsunami hazard. On 29 September 2009, within two minutes of the initiation of a normal faulting event with moment magnitude 8.1 in the outer trench-slope at the northern end of the Tonga subduction zone, two major interplate underthrusting subevents (both with moment magnitude 7.8), with total moment equal to a second great earthquake of moment magnitude 8.0, ruptured the nearby subduction zone megathrust. The collective faulting produced tsunami waves with localized regions of about 12 metres run-up that claimed 192 lives in Samoa, American Samoa and Tonga. Overlap of the seismic signals obscured the fact that distinct faults separated by more than 50 km had ruptured with different geometries, with the triggered thrust faulting only being revealed by detailed seismic wave analyses. Extensive interplate and intraplate aftershock activity was activated over a large region of the northern Tonga subduction zone.
Computing approximate solutions of integro-differential problems can be difficult and time consuming, requiring large expertize. Tau Toolbox is a numerical library that produces approximate ...polynomial solutions of differential, integral and integro-differential equations via the spectral Lanczos' Tau method. This approach, however, may fail to ensure the spectral rate of convergence, and even to reach convergence, whenever the exact solution shows singularities. This paper describes a post-processing phase based on a Frobenius-Padé approximation method to build rational approximations from the polynomial Tau approximation. This filtering extension improves the accuracy of the spectral approximation when working in the vicinity of solutions with singularities. Furthermore, some insights on how to perform such a filtering process on a piecewise version of the Tau method to tackle larger domains and/or stiff problems are offered.
In this work, we study the two-dimensional groundwater flow of fractured porous media with the help of analytic element method. A numerical solution formed by line elements called line-doublets based ...on a series expansion has been presented in the literature. In this solution, each fracture has an influence that may expand in a series that obeys Laplace’s equation exactly. The unknown coefficients are found from the discharge potentials of all other elements that are related to the expansion coefficients in series expansion. This work aims to make comparison between the computational cost for fractals by the analytic element method with different techniques like: Iterative and Matrix method.
•Two-dimensional groundwater flow of fractured porous media by the Analytic Element Method.•A numerical solution formed by line elements called line-doublets based on a series expansion.•Comparison between the computational cost (processing time) for fractals using line-doublets with different techniques like: Iterative and Matrix method.
Observational data show that in the Near Earth Asteroid (NEA) region 15% of asteroids are binary. However, the observed number of plausible doublet craters is 2–4% on Earth and 2–3% on Mars. This ...discrepancy between the percentage of binary asteroids and doublets on Earth and Mars may imply that not all binary systems form a clearly distinguishable doublet crater owing to insufficient separation between the binary components at the point of impact. We simulate the crater morphology formed in close binary asteroid impacts in a planetary environment and the range of possible crater morphologies includes: single (circular or elliptical) craters, overlapping (tear-drop or peanut shaped) craters, as well as clearly distinct, doublet craters. While the majority of binary asteroids impacting Earth or Mars should form a single, circular crater, about one in four are expected to form elongated or overlapping impact craters and one in six are expected to be doublets. This implies that doublets are formed in approximately 2% of all asteroid impacts on Earth and that elongated or overlapping binary impact craters are under-represented in the terrestrial crater record. The classification of a complete range of binary asteroid impact crater structures provides a template for binary asteroid impact crater morphologies, which can help in identifying planetary surface features observed by remote sensing.
► Binary asteroid impacts are under-represented class in the terrestrial crater record. ► We show five crater morphology types characteristical of close binary impacts. ► Single oblique impacts can easily be misinterpreted as close binary asteroid impacts. ► We estimate single and doublet population of binary asteroid impact craters. ► Help in identifying planetary surface features observed by remote sensing.
•Theoretical analysis of the spectral effects of speed-dependent line mixing.•Hard collisions, Dicke narrowed speed dependent profiles.•NH3 doublets in broad pressure range.•Guidelines for ...experiments.
We theoretically demonstrate that some doublets of NH3 broadened by Ar and heavier atoms may be suitable for the first experimental demonstration of a so-far unstudied problem: The spectral effects of the speed dependence of line-mixing. By using realistic assumptions and spectroscopic data from previous studies, we show that neglecting this process leads to errors on the spectral shape of up to 2% of the peak absorption value. When multispectrum fits are made assuming speed-independent line couplings, the peak-to-dip residuals amplitudes reduce to about 0.5% and 1% for NH3-Ar and -Xe, respectively. The magnitude of the effect is thus comparable to that of the speed dependence of the line broadening on isolated shapes, which has been demonstrated in many experimental studies. It should hence be detectable with high accuracy modern laboratory spectroscopic techniques. With this aim, guidelines and conditions paving the path for future experiments are given.
Display omitted
Bursting Rate Variability Martin Del Campo Vera, Roberto; Jonckheere, Edmond
Frontiers in physiology,
12/2021, Volume:
12
Journal Article
Peer reviewed
Open access
In this paper, a new electromyographic phenomenon, referred to as
, is reported. Not only does it manifest itself visually as a train of short periods of accrued surface electromyographic (sEMG) ...activity in the traces, but it has a deeper underpinning because the sEMG bursts are synchronous with wavelet packets in the D8 subband of the Daubechies 3 (db3) wavelet decomposition of the raw signal referred to as "
-which are absent during muscle relaxation. Moreover, the db3 wavelet decomposition reconstructs the
sEMG bursts with
contiguous relatively high detail coefficients at level 8, suggesting a high incidence of two consecutive neuronal discharges. Most importantly, the timing between successive bursts shows some variability, hence the BRV acronym. Contrary to
, where the R-wave is easily identified, here, time-localization of the burst requires a statistical waveform matching between the "
and the burst in the raw sEMG signal. Furthermore, statistical fitting of the empirical distribution of return times shows a striking difference between control and quadriplegic subjects. Finally, the BRV rate appears to be within 60-88 bursts per minute on average among 9 human subjects, suggesting a possible connection between BRV and HRV.
PDF
