Acoustic Based Crosshole Full Waveform Slowness Inversion in the Time Domain

We develop a new full waveform inversion (FWI) method for slowness with the crosshole data based on the acoustic wave equation in the time domain. The method combines the total variation (TV) regularization with the constrained optimization together which can inverse the slowness effectively. One advantage of slowness inversion is that there is no further approximation in the gradient derivation. Moreover, a new algorithm named the skip method for solving the constrained optimization problem is proposed. The TV regularization has good ability to inverse slowness at its discontinuities while the constrained optimization can keep the inversion converging in the right direction. Numerical computations both for noise free data and noisy data show the robustness and effectiveness of our method and good inversion results are yielded.

Estimation of azimuth and slowness of teleseismic signals recorded by a local seismic network

A new method that is applicable to local seismic networks to estimate the azimuth and slowness of teleseismic signals is introduced in the paper. The method is based on the correlation between the arrival times and station positions. The analyzed results indicate that the azimuth and slowness of teleseismic signals can be accurately estimated by the method. Average errors for azimuth and slowness measurements obtained by this method using data of Xian Digital Telemetry Seismic Network are 2.0?and 0.34 s/(?, respectively. The conclusions drawn from this study indicate that this method may be very useful to interpret teleseismic records of local seismic networks.

Transferable adversarial slow feature extraction network for few-shot quality prediction in coal-to-ethylene glycol process

In the coal-to-ethylene glycol(CTEG)process,precisely estimating quality variables is crucial for process monitoring,optimization,and control.A significant challenge in this regard is relying on offline laboratory analysis to obtain these variables,which often incurs substantial monetary costs and significant time delays.The resulting few-shot learning scenarios present a hurdle to the efficient development of predictive models.To address this issue,our study introduces the transferable adversarial slow feature extraction network(TASF-Net),an innovative approach designed specifically for few-shot quality prediction in the CTEG process.TASF-Net uniquely integrates the slowness principle with a deep Bayesian framework,effectively capturing the nonlinear and inertial characteristics of the CTEG process.Additionally,the model employs a variable attention mechanism to identify quality-related input variables adaptively at each time step.A key strength of TASF-Net lies in its ability to navigate the complex measurement noise,outliers,and system interference typical in CTEG data.Adversarial learning strategy using a min-max game is adopted to improve its robustness and ability to model irregular industrial data accurately and significantly.Furthermore,an incremental refining transfer learning framework is designed to further improve few-shot prediction performance achieved by transferring knowledge from the pretrained model on the source domain to the target domain.The effectiveness and superiority of TASF-Net have been empirically validated using a real-world CTEG dataset.Compared with some state-of-the-art methods,TASF-Net demonstrates exceptional capability in addressing the intricate challenges for few-shot quality prediction in the CTEG process.

On the functions of astrocyte-mediated neuronal slow inward currents

Slow inward currents are known as neuronal excitatory currents mediated by glutamate release and activation of neuronal extra synaptic N-met hyl-D-aspartate receptors with the contribution of astrocytes.These events are significantly slower than the excitatory postsynaptic currents.Parameters of slow inward currents are determined by seve ral factors including the mechanisms of astrocytic activation and glutamate release,as well as the diffusion pathways from the release site towards the extra synaptic recepto rs.Astrocytes are stimulated by neuronal network activity,which in turn excite neurons,forming an astrocyte-neuron feedback loop.Mostly as a consequence of brain edema,astrocytic swelling can also induce slow inward currents under pathological conditions.There is a growing body of evidence on the roles of slow inward currents on a single neuron or local network level.These events often occur in synchro ny on neurons located in the same astrocytic domain.Besides synchronization of neuronal excitability,slow inward currents also set synaptic strength via eliciting timing-dependent synaptic plasticity.In addition,slow inward currents are also subject to non-synaptic plasticity triggered by long-la sting stimulation of the excitatory inputs.Of note,there might be important regionspecific differences in the roles and actions triggering slow inward currents.In greater networks,the pathophysiological roles of slow inward currents can be better understood than physiological ones.Slow inward currents are identified in the pathophysiological background of autism,as slow inward currents drive early hypersynchrony of the neural networks.Slow inward currents are significant contributors to paroxysmal depolarizational shifts/interictal spikes.These events are related to epilepsy,but also found in Alzheimer's disease,Parkinson's disease,and stroke,leading to the decline of cognitive functions.Events with features overlapping with slow inward currents(excitatory,N-methyl-Daspartate-receptor mediated currents with astrocytic contribution) as ischemic currents and spreading depolarization also have a well-known pathophysiological role in worsening consequences of stroke,traumatic brain injury,or epilepsy.One might assume that slow inward currents occurring with low frequency under physiological conditions might contribute to synaptic plasticity and memory formation.However,to state this,more experimental evidence from greater neuronal networks or the level of the individual is needed.In this review,I aimed to summarize findings on slow inward currents and to speculate on the potential functions of it.

Identification and fine mapping of qSW2 for leaf slow wilting in soybean

Drought is one of the abiotic stresses limiting the production of soybean(Glycine max).Elucidation of the genetic and molecular basis of the slow-wilting(SW)trait of this crop offers the prospect of its genetic improvement.A panel of 188 accessions and a set of recombinant inbred lines produced from a cross between cultivars Liaodou 14 and Liaodou 21 were used to identify quantitative-trait loci(QTL)associated with SW.Plants were genotyped by Specific-locus amplified fragment sequencing and seedling leaf wilting was assessed under three water-stress treatments.A genome-wide association study identified 26 SW-associated single-nucleotide polymorphisms(SNPs),including three located in a 248-kb linkage-disequilibrium(LD)block on chromosome 2.Linkage mapping revealed a major-effect QTL,qSW2,associated with all three treatments and adjacent to the LD block.Fine mapping in a BC_(2)F_(3) population derived from a backcross between Liaodou 21 and R26 confined qSW2 to a 60-kb interval.Gene expression and sequence variation analysis identified the gene Glyma.02 g218100,encoding an auxin transcription factor,as a candidate gene for qSW2.Our results will contribute significantly to improving drought-resistant soybean cultivars by providing genetic information and resources.

Prediction and critical transition mechanism for granite fracture:Insights from critical slowing down theory

Rock fracture warning is one of the significant challenges in rock mechanics.Many true triaxial and synchronous acoustic emission(AE)tests were conducted on granite samples.The investigation focused on the characteristics of AE signals preceding granite fracture,based on the critical slowing down(CSD)theory.The granite undergoes a transition from the stable phase to the fracture phase and exhibits a clear CSD phenomenon,characterized by a pronounced increase in variance and autocorrelation coefficient.The variance mutation points were found to be more identifiable and suitable as the primary criterion for predicting precursor information related to granite fracture,compared to the autocorrelation coefficient.It is noteworthy to emphasize that the CSD factor holds greater potential in elucidating the underlying mechanisms responsible for the critical transition of granite fracture,in comparison to the AE timing parameters.Furthermore,a novel multi-parameter collaborative prediction method for rock fracture was developed by comprehensively analyzing predictive information,including abnormal variation modes and the CSD factor of AE characteristic parameters.This method enhances the understanding and prediction of rock fracture-related geohazards.

Similarities and differences in inherent mechanism and characteristic frequency between the one-dimensional poroelastic model and the layered White model

The similarities and differences in inherent mechanism and characteristic frequency between the onedimensional(1D)poroelastic model and the layered White model were investigated.This investigation was conducted under the assumption that the rock was homogenous and isotropic at the mesoscopic scale.For the inherent mechanism,both models resulted from quasi-static flow in a slow P-wave diffusion mode,and the differences between them originated from saturated fluids and boundary conditions.On the other hand,for the characteristic frequencies of the models,the characteristic frequency of the 1D poroelastic model was first modified because the elastic constant and formula for calculating it were misused and then compared to that of the layered White model.Both of them moved towards higher frequencies with increasing permeability and decreasing viscosity and diffusion length.The differences between them were due to the diffusion length.The diffusion length for the 1D poroelastic model was determined by the sample length,whereas that for the layered White model was determined by the length of the representative elementary volume(REV).Subsequently,a numerical example was presented to demonstrate the similarities and differences between the models.Finally,published experimental data were interpreted using the 1D poroelastic model combined with the Cole-Cole model.The prediction of the combined model was in good agreement with the experimental data,thereby validating the effectiveness of the 1D poroelastic model.Furthermore,the modified characteristic frequency in our study was much closer to the experimental data than the previous prediction,validating the effectiveness of our modification of the characteristic frequency of the 1D poroelastic model.The investigation provided insight into the internal relationship between wave-induced fluid flow(WIFF)models at macroscopic and mesoscopic scales and can aid in a better understanding of the elastic modulus dispersion and attenuation caused by the WIFF at different scales.

Structure-controlled slow dynamics in Al−Mg melts

Molecular dynamics simulation was employed to investigate the dynamical and structural properties of Al−Mg melts with the Al concentration systematically changed.The results show that the viscosity of Al67Mg33 abnormally surpasses that of Al85Mg15 below 550 K,inconsistent with the tendency at high temperatures.The evolution of the icosahedral order population is found to account for this dynamic behavior.Structural analysis shows a preferred bonding between Al and Mg atoms in the nearest neighbor shells,while a repelling tendency between them in the second shells,leading to the prepeak emergence in the partial static structure factors.The formation of icosahedral clusters is constrained in the Al-rich compositions because of the lack of sufficient Mg atoms to stabilize the clusters geometrically.These results demonstrate the structural consequence through the interplay between geometric packing and chemical interaction.These findings are crucial to understanding the structure−dynamic properties in Al−Mg melts.

Topological slow light and rainbow trapping of surface wave in valley photonic crystal bounded by air

Topological slow light and rainbow trapping tend to rely on large-scale interface structure in previous research work,which have restricted further miniaturization.In this work,we propose a method to realize slow light and rainbow trapping at the zigzag edge of a single valley photonic crystals(VPCs)bounded by air,which is very different from previous studies where rainbow trapping is supported at the interface separating two VPCs with inversion symmetry.By constructing the VPC–air boundaries and VPC–VPC interfaces experimentally,we have observed the topologically protected rainbow trapping simultaneously at the external and internal boundary.This work provides a feasible platform for the miniaturized optical communication devices such as optical buffers,optical storage and optical routing.

Electroencephalogram findings in 10 patients with post-stroke epilepsy:A retrospective study

BACKGROUND Post-stroke epilepsy is a common and easily overlooked complication of acute cerebrovascular disease.Long-term seizures can seriously affect the prognosis and quality of life of patients.Electroencephalogram(EEG)is the simplest way to diagnose epilepsy,and plays an important role in predicting seizures and guiding medication.AIM To explore the EEG characteristics of patients with post-stroke epilepsy and improve the detection rate of inter-seizure epileptiform discharges.METHODS From January 2017 to June 2020,10 patients with post-stroke epilepsy in our hospital were included.The clinical,imaging,and EEG characteristics were collected.The stroke location,seizure type,and ictal and interictal EEG manifestations of the patients with post-stroke epilepsy were then retrospectively analyzed.RESULTS In all 10 patients,epileptiform waves occurred in the side opposite to the stroke lesion during the interictal stage;these manifested as sharp wave,sharp-wave complex,or spike discharges in the anterior head lead of the side opposite to the lesion.CONCLUSION In EEG,epileptiform waves can occur in the side opposite to the stroke lesion in patients with post-stroke epilepsy.

Research of caged dynamics of clusters center atoms in Pd_(82)Si_(18) amorphous alloy

To date,there is still a lack of a comprehensive explanation for caged dynamics which is regarded as one of the intricate dynamic behaviors in amorphous alloys.This study focuses on Pd_(82)Si_(18)as the research object to further elucidate the underlying mechanism of caged dynamics from multiple perspectives,including the cage's lifetime,atomic local environment,and atomic potential energy.The results reveal that Si atoms exhibit a pronounced cage effect due to the hindrance of Pd atoms,resulting in an anomalous peak in the non-Gaussian parameters.An in-depth investigation was conducted on the caged dynamics differences between fast and slow Si atoms.In comparison to fast Si atoms,slow Si atoms were surrounded by more Pd atoms and occupied lower potential energy states,resulting in smaller diffusion displacements for the slow Si atoms.Concurrently,slow Si atoms tend to be in the centers of smaller clusters with coordination numbers of 9 and 10.During the isothermal relaxation process,clusters with coordination numbers 9 and 10 have longer lifetimes,suggesting that the escape of slow Si atoms from their cages is more challenging.The findings mentioned above hold significant implications for understanding the caged dynamics.

Preservation of superior rectal artery in laparoscopic colectomy:The best choice for slow transit constipation?

Laparoscopic colectomy with ileorectal anastomosis may be beneficial for patients with slow transit constipation who do not respond to conservative treatment,particularly if the superior rectal artery(SRA)is preserved.Several important concerns have been addressed in this commentary.It is important to first go over the definition of surgical procedure as it is used in this text.Second,the current study lacked a control group that had SRA preservation.Thirdly,it would be best to use a prospective,randomized controlled study.Lastly,a description of the mesenteric defect’s state following a laparoscopic colectomy is necessary.

Study on the simulation of acoustic logging measurements in horizontal and deviated wells

The conventional acoustic logging interpretation method, which is based on vertical wells that penetrate isotropic formations, is not suitable for horizontal and deviated wells penetrating anisotropic formations. This unsuitability is because during horizontal and deviated well drilling, cuttings will splash on the well wall or fall into the borehole bottom and form a thin bed of cuttings. In addition, the high velocity layers at different depths and intrinsic anisotropy may affect acoustic logging measurements. In this study, we examine how these factors affect the acoustic wave slowness measured in horizontal and deviated wells that are surrounded by an anisotropic medium using numerical simulation. We use the staggered-grid finite difference method in time domain （FDTD） combined with hybrid-PML. First, we acquire the acoustic slowness using a simulated array logging system, and then, we analyze how various factors affect acoustic slowness measurements and the differences between the effects of these factors. The factors considered are high-velocity layers, thin beds of cuttings, dipping angle, formation thickness, and anisotropy. The simulation results show that these factors affect acoustic wave slowness measurements differently. We observe that when the wavelength is much smaller than the distance between the borehole wall and high velocity layer, the true slowness of the formation could be acquired. When the wavelengths are of the same order （i.e., in the near-field scenarios）, the geometrical acoustics theory is no longer applicable. Furthermore, when a thin bed of cuttings exists at the bottom of the borehole, Fermat＇s principle is still applicable, and true slowness can be acquired. In anisotropic formations, the measured slowness changes with increments in the dipping angle. Finally, for a measurement system with specific spacing, the slowness of a thin target layer can be acquired when the distance covered by the logging tool is sufficiently long. Based on systematical simulations with different dipping angles and anisotropy in homogenous TI media, slowness estimation charts are established to quantitatively determine the slowness at any dipping angle and for any value of the anisotropic ratio. Synthetic examples with different acoustic logging tools and different elastic parameters demonstrate that the acoustic slowness estimation method can be conveniently applied to horizontal and deviated wells in TI formations with high accuracy.

Infant’s Sigh Breathing Matters—The Role of the Hering-Breuer Deflation Reflex in Bronchial Decongestion

Background: The prolonged slow expiratory (PSE) technique can induce sigh breaths related to the Hering-Breuer reflex in children.PSE is a specific chest physiotherapy technique often used in children to help with the clearance of secretions, reduce pulmonary obstruction and decrease ventilatory effort. Purpose: The main objective of this review was to synthesize and clarify the existing knowledge of the physiological mechanism behind the Hering-Breuer reflex and its utility in the PSE technique. The secondary objective was to provide an overview of PSE which is probably the main mechanical feature for mucus clearance in infants and to identify gaps and any further research required. Method: A comprehensive literature search was performed using PubMed/MEDLINE and Ovid EMBASE, from 1968 to January 2024, using search terms relating to “Interaction of Hering-Breuer reflex and chest physiotherapy therapy, sigh breath in infants and prolonged slow expiration technique” to create an overview of the advances and gaps in current knowledge of PSE. Result: The data obtained following treatment with PSE maneuvers in infants with histories of recurrent wheezing shows that the presence of sighs could be the main active principle of treatment. Conclusion: Changes in volume induced by PSE technique and, effects from crying may stimulate the Hering-Breuer deflation reflex and sighs in turn improving alveolar ventilation as well as lung volume in infants.

Comparative Study of Neurosurgical Complications of Thalassemia and Sickle Cell Disease

Introduction: Sickle cell disease and thalassemia are the most frequent hemoglobinopathies. During their evolution, they present certain complications, among which are two neurosurgical emergencies, namely spontaneous cranial epidural hematoma and non traumatic radiculo-medullary compression, with some particularities for each. Method: In order to highlight these particularities, we compared the characteristics of these two complications, from a number of publications reported between 2000 and 2021. Results: Sickle cell disease was complicated by spontaneous cranial epidural hematoma. Forty-two cases were reported, the mean age was 14.7 years (2 - 21 years) and the sex ratio was 6.4. The clinical presentation combined, in a non-traumatic context, signs of intracranial hypertension with those of neurological focalization. Neuroimaging showed epidural-type collection, often frontal and parietal in location. The incriminating mechanisms were ischemia, hemorrhage and extra medullary hematopoiesis. The treatment was surgical. Non traumatic radiculo-medullary was the complication of thalassemia. Of the 77 cases reported, the mean age was 27.5 years (9 - 66 years) and the sex ratio was 4.1. The lesions were epidural with a clear thoracic predominance and resulted from extra marrow hematopoiesis. Treatment included: hypertransfusion, radiotherapy, hydroxyurea and surgery. Vital and functional prognosis were globally satisfactory when the management was rapid. Conclusion: Cranial and spinal epidural lesions, respective complications of sickle cell disease and thalassemia, result from similar mechanisms. Their prognosis depends on the rapidity of management. .

Simulating the Dynamics of Bimetallic Clusters Deposited onto a Surface Using Molecular Dynamics

This paper examines the interface development between a single crystalline Ag matrix and core-shell AgnCom nanoclusters that have been deposited with energies varying between 0.25 eV and 1.5 eV per atom using computer modeling techniques. Clusters undergo deformation as a result of the slowing down;they may also become epitaxial with the substrate and maintain their core-shell structure. A detailed analysis of the effects of the cluster-surface interaction is conducted over a realistic size and energy range, and a model is created to show how clusters accumulate. It is discovered that both the silver shells and the cobalt cluster cores exhibit limited epitaxy with the substrate, and that the contact produced is only a few atomic layers thick. The effect is higher for Ag shells than for Co cores, and it is not very energy dependent.

Extraction method of component waves in full waveform acoustic data and its application

In conventional slowness-time coherence(STC)method,slowness and time need to be searched at the same time,which limits the precision and lowers the efficiency.The dichotomy method combined with slowness-time coherence algorithm aims to enhance the efficiency of data processing and to improve the precision.The algorithm changes the searching pattern of conventional slowness-time coherence method to acquire the slowness of component waves in array acoustic logging data.Based on energy ratio of short time window versus long time window and slowness-time coherence method,the algorithm first acquires the arrivals of the component waves using energy ratio of short time window versus long time window method.It then uses the calculated results as the arrivals in conventional slowness-time coherence method,so the slowness-time two-dimensional searching process is simplified to slowness searching process.Based on dichotomy method,the searching pattern is further optimized in replace of the ergodic searching pattern in conventional slowness-time coherence method,which means that as the iteration proceeds,the current searching interval is reduced to half of the former,so the number of searching times is decreased.The dichotomy method combined with slowness-time coherence algorithm is applied to well L in the data processing.Compared with conventional slowness-time coherence method,for compressional wave,the searching efficiency of the algorithm is 4.53 times better,while for Stoneley wave,the searching efficiency is 1.85 times better.Compared with conventional logging data,the average absolute error of the results of the dichotomy method combined with slowness-time coherence algorithm is 1.14μs/ft smaller than that of the conventional method,while the average relative error is 1.2 percent lower.The dichotomy method combined with slowness-time coherence algorithm shows good results in its application,which can enhance the processing efficiency remarkably while getting reliable results at the same time.

Application of 3D stereotomography to the deep-sea data acquired in the South China Sea:a tomography inversion case

A 3D stereotomography algorithm, which is derived from the 3D Cartesian coordinate, is applied for the first time to the deep-sea data acquired in the LH area, South China Sea, to invert a macro velocity model for pre-stack depth migration. The successful implementation of stereotomography is highly dependent on the correct extraction of slowness components and the proper application of regularization terms. With the help of the structure tensor algorithm, a high-quality 3D stereotomography data space is achieved in a very efficient manner. Then, considering that the horizontal slowness in cross-line direction is usually unavailable for 3D narrow-azimuth data, the regularization terms must be enhanced to guarantee a stable convergence of the presented algorithm. The inverted model serves as a good model for the 3D pre-stack depth migration. The synthetic and real data examples demonstrated the robustness and effectiveness of the presented algorithm and the related schemes.

Migration and Transformation of Coated Controlled Release Nitrogen in Soil under Co-situs Application Mode

By using field trials, the migration and transformation of coated controlled release nitrogen （YZS80） in soil under the co-situs application mode were studied. The results indicated that YZS80 nitrogen dissolved out in average speed of about 0.4%/d and 32% totally in 80 d compared with common compound fertUizer. For YZS80, in the vertical downward direction of application points, urea nitrogen content increased significantly （P 〈0.05） in the 45 -80 d and the 30 -60 cm soil layers; nitrate nitrogen content was little change range and in moderate （10 -100 mg/kg） in 0 -80 d and 10 -60 cm soil layers, but increased significantly （ P 〈0.05） 45 -80 d compared to 0 -45 d; ammonium nitrogen content was significant lower （P〈0.05） before 45 d in 10 -30 cm soil layers, but significant higher（P〈0.05） after 45 d in 10 -60 cm soil layers; NO3^- -N/NH4^＋ -N meets gradually the needs of the crop with the extension of time. Under the co-situs application mode, the possibility of burning root and salt injury and loss dsk of nitrate leaching is a significant reduction.

Effect of Slow and Controlled Release Fertilizers on the Yield and Nutrient Use Efficiency of Hot Pepper in Qiu-bei

[Objective] The aim of this study was to investigate the impacts of slow and controlled release fertilizers（SCRF）on the yield of qiubei hot pepper,its nutrient use efficiency and environment.[Method] Using Qiubei hot pepper（Capsicum frutescens L.）as the experimental material,we studied the fertilization effect and environment-protecting effect of SCRF.[Result] The result showed that SCRF could improve the agronomic characteristics of hot pepper.Compared to singly applied common fertilizers,SCRF increased economic yield by 20.90% and economic benefit by 13 234.35 Yuan/hm2,and the ratio of output to input was improved by 47.93%.In comparison with common straight fertilizers at same NPK proportion and rate,SCRF increased economic yield by 5.26% and economic benefit by 5 554.80 Yuan/hm2,and the ratio of output to input was improved by 9.91%.Under the reduced use of SCRF by 20%,SCRF increased economic yield by 12.38% and economic benefit by 9595.20 Yuan/hm2 compared with singly applied common fertilizers,and the ratio of output to input was improved by 65.95%.SCRF improved nitrogen,phosphorus and potassium use efficiencies by 12.42-17.53,3.35-5.24 and 5.37-14.02 percents respectively.[Conclusion] As the result of much reduced N and P application rates,SCRF would significantly economize fertilizer resources and minimize the pollution caused by the loss of fertilizer nutrients,which is of practical importance for environment protection.