Dataset of antiarch placoderms (the most basal jawed vertebrates) throughout Middle Paleozoic

Antiarch placoderms, the most basal jawed vertebrates, have the potential to enlighten the origin of the last common ancestor of jawed vertebrates. Quantitative study based on credible data is more convincing than qualitative study. To reveal the antiarch distribution in space and time, we created a comprehensive structured dataset of antiarchs comprising 64 genera and 6025 records. This dataset, which includes associated chronological and geographic information, has been digitalized from academic publications manually into the DeepBone database as a dateset. We implemented the paleogeographic map marker to visualize the biogeography of antiarchs. The comprehensive data of Antiarcha allow us to generate its biodiversity and variation rate changes throughout its duration. Structured data of antiarchs has tremendous research potential, including testing hypotheses in the fields of the biodiversity changes, distribution, differentiation,population and community composition. Also, it will be easily accessible by the other tools to generate new understanding on the evolution of early vertebrates. The data file described in this paper is available on https://doi.org/10.5281/zenodo.5639529 (Pan and Zhu, 2021).

Longitudinal remagnetization of uniaxial antiferromagnetic nanoparticles: the role of spontaneous magnetic moment

A kinetic theory of magnetic response of uniaxial antiferromagnetic nanoparticles is presented. Within the developed framework, a particular case when an external field is applied strictly along the anisotropy axis is considered in detail. Analysis of the relaxation spectrum of an antiferromagnetic particle with a spontaneous magnetic moment is performed. It is shown that in a wide frequency range the magnetic response of such particle is determined entirely by the relaxation mode with the longest time. An analytical expression for this time that explicitly contains a value of the decompensation magnetic moment is derived. Also, simple formulae for both static and dynamic longitudinal magnetic susceptibility of an antiferromagnetic nanoparticle are obtained. According to them, longitudinal susceptibility grows quadratically with the value of the spontaneous magnetic moment. Besides, if the latter is not zero, the change of the static susceptibility with temperature turns out to be non-monotonic. The influence of the spontaneous magnetic moment of the particle on the magnetization curves in strong fields is analysed using both energy approach and kinetic theory. The calculated dependences of the dynamic coercivity on the amplitude and variation rate of the applied field are qualitatively compared with experimental data. This article is part of the theme issue ‘Transport phenomena in complex systems (part 2)’.

Updated Absolute Gravity Rate of Change Associated With Glacial Isostatic Adjustment in Southeast Alaska and Its Utilization for Rheological Parameter Estimation

In Southeast Alaska (SE-AK), rapid ground uplift of up to 3 cm/yr has been observed associated with post-Little Ice Age glacial isostatic adjustment (GIA). Geodetic techniques such as global navigation satellite system (GNSS) and absolute gravimetry have been applied to monitor GIA since the last 1990s. Rheological parameters for SE-AK were determined from dense GNSS array data in earlier studies. However, the absolute gravity rate of change observed in SE-AK was inconsistent with the ground uplift rate, mainly because few gravity measurements from 2006 to 2008 resulted in imprecise gravity variation rates. Therefore, we collected absolute gravity data at six gravity points in SE-AK every June in 2012, 2013, and 2015, and updated the gravity variation rate by reprocessing the absolute gravity data collected from 2006 to 2015. We found that the updated gravity variation rate at the six gravity points ranged from −2.05 to −4.40 μGal/yr, and its standard deviation was smaller than that reported in the earlier study by up to 88 %. We also estimated the rheological parameters to explain the updated gravity variation rate, and their optimal values were determined to be 55 km and 1.2 × 10^19 Pa s for lithospheric thickness and upper mantle viscosity, respectively. These optimal values are consistent with those independently obtained from GNSS observations, and this fact indicates that absolute gravimetry can be one of the most effective methods in determining sub-surface structural parameters associated with GIA accurately. Moreover, we utilized the gravity variation rates for estimating the ratio of gravity variation to vertical ground deformation at the six gravity points in SE-AK. The viscous ratio values were obtained as −0.168 and −0.171 μGal/mm from the observed data and the calculated result, respectively. These ratios are greater (in absolute) than those for other GIA regions (−0.15 to −0.16 μGal/mm in Antarctica and Fennoscandia) because glaciers in SE-AK have melted more recently than in other regions.

An Adaptive Backstepping Sliding Mode Cascade-Control Method for a DC Microgrid Based on Nonlinear Virtual Inertia

In order to improve the bus voltage robustness of distributed multi-source DC microgrid, a new cascade control method based on nonlinear virtual inertia and adaptive backstepping sliding mode is proposed. Firstly, the mathematical model of distributed multi-source DC microgrid with a buck–boost interface converter is analyzed and established. A nonlinear virtual inertia control method based on a variable droop coefficient is given by introducing the converter output voltage variation rate feedback term and a saturation function equation. Secondly, the voltage and current double closed-loop cascade controller is designed by using backstepping sliding mode control and adaptive algorithms. Finally, the system and cascade control models are built in MATLAB/Simulink for multi-case simulation. The feasibility and effectiveness of the proposed method is verified by comparing the results with traditional control methods.

Study on cyclic variation rate of fuel flow in the nozzle during fuel injection

The fuel flow pattern in the fuel injection nozzle of diesel engine is a complex and changeable phenomenon, which is easily affected by various factors, bringing the differences of flow patterns between multiple injection cycles. To solve the above problem, a visual experimental platform of fuel injection nozzle was built, in which the 100 injection cycles of diesel engine on the same working condition were photographed via shadowgraphy to study the difference in fuel flow pattern in the nozzle by ensemble average processing method. The cyclic variation rate K of fuel flow pattern is defined. Results demonstrate that the fuel flow pattern tends to be the same in multiple fuel injection cycles, but there is a strong randomness at the starting of injection and after ending of injection; the K can be reduced by decreasing the injection pressure and the inclination angle of orifice, so that the fuel flow pattern in the nozzle tends to be consistent.

Effects of calorie intake and sampling time on thyroid stimulating hormone concentration

BackgroundThis study aimed to investigate the effects of blood collected after calorie intake on the level of thyroid stimulating hormone (TSH), comparing with the blood collected in fasting state.MethodsThis study was a prospective, randomized, controlled study. Subjects from the outpatients in the department of endocrinology without evident of thyroid diseases were included and then randomized into the fasting group, diet intake group, and glucose intake group, respectively. Fasting blood was collected from all the subjects at 7:00 am for the measurement of TSH and free thyroxine (FT4). Afterward, the subjects were maintained at fasting state (fasting group), had an intake of the mixed diet with the calories of 400 Kcal (diet intake group), and had an intake of 75 g glucose (glucose intake group), respectively, and blood was acquired again 2 h later (9:00 am on the same day) for TSH and FT4 measurement. The levels between 7:00 am and 9:00 am were compared.ResultsOf the 150 subjects, 146 met the inclusion criteria, of which 48, 48, and 50 were in the diet intake group, glucose intake group, and fasting group, respectively. The TSH in the diet intake group was significantly lower at 9:00 am (TSH9am) than the level at 2h before (TSH7am) (P<0.001), of which the median variation was -0.71 mU/L, and the median variation rate was -32.4%. In the glucose intake group, the TSH9am was also significantly lower than TSH7am (P<0.001), of which the median variation was -0.73 mU/L, and median variation rate was -31.5%. While in the fasting group, the TSH9am decreased slightly but statistically significantly lower than TSH7am (P<0.001), of which the median variation was -0.1 mU/L, and the median variation rate was -5.2%. According to TSH7am, 9 subjects in total (3 subjects in each group) met the diagnostic criteria of subclinical hypothyroidism. However, according toTSH9am, only 2 patients in the fasting group still met the diagnostic criteria of subclinical hypothyroidism.ConclusionComparing with the fasting state, the TSH level at 2h after the calorie intake was decreased by about 30%, which could influence the diagnosis of subclinical hypothyroidism.Trial registrationChiCTR2100047454.

Model Study on the Combination of Operating Parameters of Corn Kernel Harvesters

This study analyzed the engine operating condition curve of the corn kernel harvester. Field experiments identified the feed rate, concave clearance, and cylinder speed as the main factors affecting operating quality and efficiency. A ternary quadratic regression orthogonal center-of-rotation combined optimization test method was used to determine the feed rate, cylinder speed, and concave clearance as the influencing factors, and the engine speed variation rate, crushing rate, impurity rate, loss rate, and cylinder speed variation rate as the objective functions. A mathematical regression model was developed for the combination of operating quality indicators, efficiency indicators, and operating parameters of the corn kernel harvester. A non-linear optimization method was used to optimize the parameters of each influencing factor. The results showed that with a feed rate of 12 kg/s, a forward speed of 5 km/h, a cylinder speed of 360 r/min, and a concave clearance of 30 mm, the average crushing rate was 3.91%, the average impurity rate was 1.71%, and the kernel loss rate was 3.1%. This model could be used for the design and development of intelligent control systems.

On the relation of the lunar recession and the length-of-the-day

We review the problem of the consistency between the observed values of the lunar recession from Lunar Laser Ranging (LLR) and of the increase of the length-of-the-day (LOD). From observations of lunar occultations completed by recent IERS data, we derive a variation rate of the LOD equal to 1.09 ms/cy from 1680 to 2020, which compares well with McCarthy and Babcock (Phys. Earth Planet. Inter. 44: 281, 1986) and Sidorenkov (Astron. Astrophys. Trans. 24: 425, 2005). This rate is lower than the mean rate of 1.78 ms/cy derived by Stephenson et al. (Proc. R. Soc. A 472: 20160404, 2016) on the basis of eclipses in the Antiquity and Middle Age. The difference in the two observed rates starts at the epoch of a major change in the data accuracy with telescopic observations. The observed lunar recession appears too large when compared to the tidal slowing down of the Earth determined from eclipses in the Antiquity and Middle Age and even much more when determined from lunar occultations and IERS data from 1680 to 2020. With a proper account of the tidal effects and of the detailed studies on the atmospheric effects, the melting from icefields, the changes of the sea level, the glacial isostatic adjustment, and the core-mantle coupling, we conclude that the long-standing problem of the presence or absence of a local cosmological expansion is still an open question.

Electromagnetic Exposure Dosimetry Study on Two Free Rats at 1.8 GHz via Numerical Simulation

Normally, the impact of electromagnetic exposure on human health is evaluated by animal study. The biological effect caused by electromagnetic exposure on such experimental animals as rats has been proven to be dose-dependent. However, though the dose of radio frequency (RF) electromagnetic exposure described by the specific absorbing rate (SAR) on fixed rats has been relatively well-studied utilizing the numerical simulations, the dosimetry study of exposure on free rat is insufficient, especially in the cases of two or more free rats. Therefore, the present work focuses on the variation of SAR caused by the existence of neighboring free rat in the same cage. Here, infrared thermography was used to record the activity of the two free rats who lived in the same cage that mounted at the far-field region in the microwave darkroom for a duration of 48 h. Then, using image processing techniques, the relative positions and orientations of the two rats are identified, which are defined by three parameters, such as the relative distance (d), relative direction angle (α), and relative orientation angle (β). Using the simulation software XFdtd 7.3, the influence of d, α, and β on the whole-body average SAR (WB-avgSAR) of the rats exposed to 1.8 GHz electromagnetic wave was calculated and analyzed. Then, the average variation of WB-avgSAR of the two rats compared with that of a single rat within 48 h was calculated. The numerical simulation results showed that the relative posture position described by (d, α, and β) of the two rats affects their WB-avgSAR and leads to fluctuations at different positions. However, the variation rate of the 48-h-average WB-avgSAR was only 10.3%, which implied that the over-time average SAR of two or more rats can be roughly described by the WB-avgSAR of a single free rat, except when a real-time precise control of exposure dose is necessary.

Technology for Location, Analysis and Interpretation of Magnetic Alterations as Precursors of Seismic Phenomena Update

To date, several studies have shown that the Earth's magnetic field suffers alterations at the local geographical location before an earthquake occur. Its study demonstrates that the Earth’s magnetic alterations at specific local geographical zone, is a local seismic precursor alerting a proximity of an earthquake with a margin of error of approximately 10%. The electromagnetic noise from background is very confusing, but that reason was necessary to identify these electromagnetic signal precursors by filtering a large amount of noise. To isolate the electromagnetic noise, was implemented a Magnetic North deflection detection in Smart Phones Magnetometers. Using it technology, was developed a mathematical algorithm that work in combination with the Smart Phones magnetometers. This research was based using in reference the study carried out by the Department of Physics of the Faculty of Physical Sciences and Mathematics (FCFM) of the University of Chile directed by Cordado, 2018[1], in the paper called “Latitudinal variation rate of geomagnetic cutoff rigidity in the active Chilean convergent margin”.