Diminution Of Amplitude Research Articles

PO-700-01 IMPACT OF VACCINATION STATUS ON QRS AMPLITUDE DIMINUTION IN PATIENTS HOSPITALIZED WITH COVID-19

We have previously described the prognostic utility of QRS amplitude diminution (LoQRS) in predicting mortality and clinical decompensation in patients with COVID-19. However, whether and how COVID-19 vaccination status modulates risk prediction is not currently known.

Comprehensive insights into the thermal and mechanical effects of metallic glasses via creep

• Evolution of deformation and relaxation behavior of a Zr-based MG was explored by extensive creep tests under physical aging and cyclic loading. • Relaxation-time spectra were further utilized to quantitatively describe the time scales involve in the creep of MGs. • An annihilation of local deformation units during physical aging and cyclic loading was detected through the diminution of amplitude in both activation energy and relaxation-time spectra. Evolution of deformation and relaxation behaviors of a prototypical Cu 46 Zr 46 Al 8 metallic glass was explored by extensive creep tests under both physical aging and cyclic loading. Deep insights into the microstructure-induced dynamic heterogeneity which accommodates creep deformation were successively revealed via experimental measurements and spectral analyses. An annihilation of local defects within metallic glass with increasing annealing time and cyclic numbers was observed through the reduction of amplitude in both activation energy spectra and relaxation-time spectra, which were also accompanied by an ascending value of β K W W . It is further found that the corresponding deformation units within the metallic glass do not disappear permanently, but are recoverable over the course of cyclic loading. The apparent suppressed relaxation process can be gradually alleviated with increasing resuming time between two consecutive cycles, behaving differently from physical aging, which indicates a notable discrepancy between thermal treatment and mechanical treatment.

Prognostic Value of Electrocardiographic QRS Diminution in Patients Hospitalized With COVID-19 or Influenza

During the clinical care of hospitalized patients with COVID-19, diminished QRS amplitude on the surface electrocardiogram (ECG) was observed to precede clinical decompensation, culminating in death. This prompted investigation into the prognostic utility and specificity of low QRS complex amplitude (LoQRS) in COVID-19. We retrospectively analyzed consecutive adults admitted to a telemetry service with SARS-CoV-2 (n = 140) or influenza (n = 281) infection with a final disposition—death or discharge. LoQRS was defined as a composite of QRS amplitude <5 mm or <10 mm in the limb or precordial leads, respectively, or a ≥50% decrease in QRS amplitude on follow-up ECG during hospitalization. LoQRS was more prevalent in patients with COVID-19 than influenza (24.3% vs 11.7%, p = 0.001), and in patients who died than survived with either COVID-19 (48.1% vs 10.2%, p <0.001) or influenza (38.9% vs 9.9%, p <0.001). LoQRS was independently associated with mortality in patients with COVID-19 when adjusted for baseline clinical variables (odds ratio [OR] 11.5, 95% confidence interval [CI] 3.9 to 33.8, p <0.001), presenting and peak troponin, D-dimer, C-reactive protein, albumin, intubation, and vasopressor requirement (OR 13.8, 95% CI 1.3 to 145.5, p = 0.029). The median time to death in COVID-19 from the first ECG with LoQRS was 52 hours (interquartile range 18 to 130). Dynamic QRS amplitude diminution is a strong independent predictor of death over not only the course of COVID-19 infection, but also influenza infection. In conclusion, this finding may serve as a pragmatic prognostication tool reflecting evolving clinical changes during hospitalization, over a potentially actionable time interval for clinical reassessment.

B-PO01-082 ARTIFICIAL INTELLIGENCE-ASSISTED QRS AMPLITUDE ANALYSIS OF THE PRESENTING ELECTROCARDIOGRAM PREDICTS MORTALITY IN COVID-19

Artificial Intelligence (AI) has shown promise in augmenting ECG analysis. We previously identified QRS amplitude diminution as a predictor of mortality in COVID-19 on follow-up ECG; but ECG data would be most useful clinically if predictive upon admission. To assess whether QRS amplitude on the admission ECG predicts mortality in COVID-19 utilizing AI processing techniques. We performed a retrospective analysis of patients admitted with laboratory confirmed SARS-CoV-2 between March 5 and July 7, 2020 (n=4,709). Patients were excluded if the ECG was not acquired within 72 hrs of admission (n=1,692). Low QRS Amplitude (LoQRS) was defined by a composite of QRS amplitude <5mm in the limb leads AND/OR <10mm in the precordial leads (a composite of V1-V3 and V4-V6). Among 3,012 patients, 373 (14.1%) met criteria for LoQRS (Figure). Compared to patients without LoQRS, these patients had a higher risk of in-hospital mortality (17.4% vs. 10.6%, p<0.001), ICU admission (31.9% vs 22.2%, p<0.001), and mechanical ventilation (26.3% vs 17.5%). Low QRS amplitudes were noted in both limb and precordial leads. In multivariable models, LoQRS was independently associated with mortality (OR 1.55, 95% CI 1.2-2.00, p<0.001) as were age (OR 1.05, 95% CI 1.04-1.06), BMI (OR 1.02, 95% CI 1.01-1.03), and CKD (OR 1.49, 95% CI 1.06-2.12). LoQRS also independently predicted ICU admission (OR 1.7, 95% CI 1.32-2.18) and mechanical ventilation (OR 1.6, 95% CI 1.23-2.00). QRS amplitude on the presenting ECG independently predicts mortality, ICU admission, and mechanical ventilation in hospitalized patients with COVID-19, and may allow initial risk stratification.

De-bonding assessment of rebars using an ultrasonic method with laser vibrometer tests and numerical simulations

“Perfect bonding” of reinforcement steel and concrete is a desired condition in practice, but any reinforcement defect (corrosion, crack) or concrete distress reduces the quality of steel-mortar bonding. Degradation of steel rebar – concrete bond because of steel corrosion is the most common process leading to reduction in service capacity or failure in reinforced concrete (RC) structures. Corrosion-related bond degradation decreases the RC element's strength and also tends to accelerate the corrosion process. Common practice for de-bonding detection is invasive, often destructive, and is not satisfactory for practical use in RC condition assessment.In this study, an experimental and mathematical simulation approach based on the ultrasonic guided wave method is developed to non-destructively distinguish the differences in bond quality for corrugated and smooth steel bars embedded in concrete cylinders. For the experiments, a highly sensitive laser vibrometer is used to capture displacement versus time signals. Numerical simulation is verified first by comparing numerical results with analytic equations, and then by comparing with experimental results. Results from the tests and simulations confirm that when there is “perfect bonding” between the steel bars and mortar, wave energy leaks easily into the mortar and higher frequency waves dissipate before arriving at the end of the bar. In contrast, for poorly-bonded specimens, high frequency displacement waves travel mostly through the steel: an amplitude diminution of five times is observed for the poorly-bonded experimental specimens. Frequency analysis also showed that there is a significant drop in overall energy content of the signal for perfectly-bonded samples in comparison to de-bonded samples because of more wave energy leakage in a broad spectrum. This study shows that the acoustic wave propagation method can reveal the degree of steel reinforcement de-bonding in a non-destructive manner. Although there will be challenges in application of this method in the field, it is most likely to be useful on a year-to-year basis to evaluate progressive de-bonding from corrosion of RC structures for better risk management analysis.

Early postural adjustments in football players with cerebral palsy

Introduction: The functional limitations associated with Cerebral Palsy (CP) and inactivity are directly related to the deficit in postural control, namely the Early Postural Adjustments (EPAs). On the other hand, same studies showed that the practice of physical exercise can improve stability. Objectives: Thus, the goal of the present study was to evaluate the influence of physical exercise, in this case in a football player, on the EPAs of athletes with CP. Methods: The study included 5 young male adults with CP, aged between 18 and 36 years old, all football players, class 7 and 8.The electromyographic activity was recorded using Delsys Trigno and the ratio of the postural musculature [soleus (SO) and tibialis anterior (TA)] prior to a step motion, as well as the center of pressure displacement amplitude were calculated through the force platforms (Bertec), before and after a 4 month interval of training. The two moments of evaluation were compared using the Wilcoxon test and the Spearman correlation between the CoP amplitude and the muscular activity ratio was calculated.Participants were recruited in a first period in which they had no physical activity at all and in the following 4 months they started training regularly, with a frequency of three times a week for 1h30min, always with the same trainer and in the same physical training space. Results: There was a statistically significant decrease in the anterior CoP amplitude (-4.47cm; p=0.043) after 4 months, with a negative correlation between this amplitude and the ratio of TA / SO (r=-0.90; p=0.037). In the lateral direction, a diminution of amplitude of minimum CoP (-1.49; p=0.893) without statistically significant correlation (r=0.10; p=0.873) was found. Conclusions: Practicing sport, even in pathology, has a significant effect on the improvement of postural oscillation, with an increase in the relationship between muscular activity and postural control.

P- and S-wave attenuation in the Kopili region of northeastern India

We comprehensively analyze attenuation factor in Kopili region and its neighboring area. Corresponding to influence of frequency on attenuation, QP and QS are estimated from direct P and S waves. The results establishes higher values of Q for S waves (QS=(101±4)f(1.4±0.05)) than for P waves (QP=(45±3)f(1.3±0.07))in the 1.5-12 Hz frequency band. It is seen that our findings agree with other published results on tectonically active regions that is characterized by high degree of heterogeneity. Hence, it can be useful for further studies in ground motion prediction in Kopili region. The low value of quality factors corresponding to P and S waves refers to seismically actives areas with complex heterogeneity. The estimated value of QS/QP and their subsequent association with frequency affirm the dominance of scattering as a major contribution to diminution of seismic amplitudes. This is further corroborated by local geological settings.

Postępująca kardiomiopatia nieniedokrwienna powodująca nadczułość załamka T i nieprawidłową stymulację — opis przypadku

T-wave oversensing is one of the causes of inappropriate shocks. It results from various conditions including progressive cardiomyopathy, diminution of R-wave amplitude and relative or dynamic gain in the T-wave amplitude, electrolyte abnormalities, injury current-related increase in the T-wave voltage. We report a 59-year-old patient who presented with implantable cardioverter defibrillator shocks after 5 year implantation with decreased R-wave amplitude and T-wave changes on 12-lead electrocardiography.

Continuous Wavelet Transform Based Spectral Decomposition of 3d Seismic Data for Reservoir Characterization in Oyi Field, se Niger Delta

Continuous Wavelet Transform (CWT) is one of the most used wavelet transform based spectral decomposition methods in the direct detection of hydrocarbons and as an indicator of stratigraphic variability due to its optimal time-frequency resolution and variable time window requirements. CWT based spectral decomposition was applied on a 3D Post Stack Time Migrated (PSTM) seismic data acquired over a producing field using morlet wavelet and a time varying analysis window. Frequency amplitude slices of 10 Hz to 50 Hz were extracted from a 1625 ms HD1 seismic horizon and analyzed for possible hydrocarbon indications and stratigraphy. Hydrocarbon filled reservoir sands were delineated as low frequency high amplitude spectral anomalies between 20 Hz to 30 Hz frequency band coincident with the locations of producing wells in the field. Also, high frequency high amplitude spectral anomaly were delineated at predominantly 50 Hz frequency indicating a thin-bed with probable hydrocarbon saturation particularly gas, suspected to be a bypass hydrocarbon zone. Result also shows amplitude diminution with increasing frequency attributed to local variations in lithology. Therefore, appropriate application of this method will improve reservoir characterization and enhanced bed thickness definition, de-risk prospects and minimize dry well drilling in the field.

A novel paraplegia model in awake behaving macaques.

Lower limb paralysis from spinal cord injury (SCI) or neurological disease carries a poor prognosis for recovery and remains a large societal burden. Neurophysiological and neuroprosthetic research have the potential to improve quality of life for these patients; however, the lack of an ethical and sustainable nonhuman primate model for paraplegia hinders their advancement. Therefore, our multidisciplinary team developed a way to induce temporary paralysis in awake behaving macaques by creating a fully implantable lumbar epidural catheter-subcutaneous port system that enables easy and reliable targeted drug delivery for sensorimotor blockade. During treadmill walking, aliquots of 1.5% lidocaine with 1:200,000 epinephrine were percutaneously injected into the ports of three rhesus macaques while surface electromyography (EMG) recorded muscle activity from their quadriceps and gastrocnemii. Diminution of EMG amplitude, loss of voluntary leg movement, and inability to bear weight were achieved for 60-90 min in each animal, followed by a complete recovery of function. The monkeys remained alert and cooperative during the paralysis trials and continued to take food rewards, and the ports remained functional after several months. This technique will enable recording from the cortex and/or spinal cord in awake behaving nonhuman primates during the onset, maintenance, and resolution of paraplegia for the first time, thus opening the door to answering basic neurophysiological questions about the acute neurological response to spinal cord injury and recovery. It will also negate the need to permanently injure otherwise high-value research animals for certain experimental paradigms aimed at developing and testing neural interface decoding algorithms for patients with lower extremity dysfunction.NEW & NOTEWORTHY A novel implantable lumbar epidural catheter-subcutaneous port system enables targeted drug delivery and induction of temporary paraplegia in awake, behaving nonhuman primates. Three macaques displayed loss of voluntary leg movement for 60-90 min after injection of lidocaine with epinephrine, followed by a full recovery. This technique for the first time will enable ethical live recording from the proximal central nervous system during the acute onset, maintenance, and resolution of paraplegia.

Attentional resources modulate error processing-related brain electrical activity: Evidence from a dual-task design

Attention plays an important role in the processing of error, but only a few studies have explored the relationship between them. The current study used a dual-task paradigm, combining the classic flanker task with a working memory load task, to explore how changes in the amount of attentional resources modulate error negativity (Ne) and error positivity (Pe). The results showed that the reduction of attentional resources overall caused a decrease in Pe amplitude, especially in the late stage of Pe, which had a significant diminution in amplitude. However, changes in the amount of attentional resources did not cause significant changes in the Ne amplitude. These results suggest that the early stage of error processing in the Ne time window is less affected by attention, but the Pe stage is regulated by attentional resources, especially in the late Pe stage.

Interaction between the serotoninergic and GABAergic systems in frog retina as revealed by electroretinogram

Functional interactions between serotoninergic and GABAergic systems in the vertebrate retina are largely unknown. In this study, the effects of isolated or combined stimulation of the serotonin receptors (with 100 μM serotonin) and ionotropic GABAA and GABAC receptors (with 5mM TACA) on the electroretinographic (ERG) ON (b‑wave) and OFF (d‑wave) responses were investigated in frog eyecup preparations. It was found that serotonin alone produced asignificant enhancement of the b‑ and d‑wave amplitude, while TACA alone caused its marked diminution. The relative amplitude diminution, caused by the TACA treatment, was significantly smaller when TACA was applied on the background of the fully developed serotonin effect. This result suggests that the retinal serotoninergic system could diminish the effects of ionotropic GABA receptor activation on the ERG wave generator mechanisms. In order to separately evaluate the effects of the GABAC receptor activation, in asubset of experiments the effects of TACA or TACA + serotonin were tested during GABAA receptor blockade with 100 μM bicuculline. Bicuculline alone caused amarked increase of the b‑ and d‑wave amplitude. The stimulation of GABAC receptors (with TACA) during bicuculline action produced astrong diminution of the b‑ and d‑wave amplitudes. Similar relative decrease of the b‑wave amplitude was produced when TACA was applied in combination with serotonin, while the relative decrease of the d‑wave amplitude was less pronounced during treatment with serotonin + TACA than TACA alone. Our results demonstrate that there is an ON/OFF asymmetry in the receptors involved in the presumed interactions between serotoninergic and GABAergic systems. Serotonin may decrease the effects of GABAA receptor activation in the ON pathway, while it may decrease the effects of both GABAA and GABAC receptor activation in the OFF pathway.

Dynamic Fatigue Does Not Alter Soleus H-Reflexes Conditioned by Homonymous or Heteronymous Pathways.

H-reflex depression (diminution of amplitude after a conditioning stimulus) is mediated presynaptically and therefore can help distinguish central versus peripheral mechanisms of fatigue. We examined the effects of a dynamic exercise protocol on H-reflex depression using two conditioning methods: homonymous conditioning (paired-pulse tibial nerve stimulation); and heteronymous conditioning (common peroneal nerve stimulation). Ten subjects performed dynamic contractions of the soleus muscle through 30° ankle range of motion. The concentric phase required a target force of 10% of maximum voluntary isometric contraction (MVIC) and the eccentric phase force target was 80% MVIC. Fatigue persisted for >20 min after cessation of the exercise. Compared with prefatigue values, the dynamic fatigue protocol did not increase presynaptic inhibition after either homonymous or heteronymous conditioning. Peak to peak amplitude of unconditioned H-reflexes was likewise unchanged despite a long term depression of muscle force (long duration fatigue). These results suggest that persistent fatigue after dynamic exercise is attributed to muscle changes and not altered spinal mechanisms.

Early selectivity for vocal and musical sounds: electrophysiological evidence from an adaptation paradigm.

There is growing interest in characterizing the neural basis of music perception and, in particular, assessing how similar, or not, it is to that of speech. To further explore this question, we employed an EEG adaptation paradigm in which we compared responses to short sounds belonging to the same category, either speech (pseudo-sentences) or music (piano or violin), depending on whether they were immediately preceded by a same- or different-category sound. We observed a larger reduction in the N100 component magnitude in response to musical sounds when they were preceded by music (either the same or different instrument) than by speech. In contrast, the N100 amplitude was not affected by the preceding stimulus category in the case of speech. For P200 component, we observed a diminution of amplitude when speech sounds were preceded speech, compared to music. No such decrease was found when we compared the responses to music sounds. These differences in the processing of speech and music are consistent with the proposal that some degree of category selectivity for these two classes of complex stimuli already occurs at early stages of auditory processing, possibly subserved by partly separated neuronal populations.

Value of Two Dimensional Echocardiography for Assessment of Disease Severity in Patients With Pulmonary Hypertension

To carry out complex assessment of the right ventricular (RV) function with two-dimensional echocardiography (2D-EchoCG) for detection of most informative markers of the disease severity in patients with pulmonary hypertension (PH). We examined 63 patients with PH (38 with idiopathic PH, 7 with corrected congenital heart defects, 6 with systemic scleroderma, 12 with chronic inoperable thromboembolic PY). Examination included right heart catheterization, 2D-EchoCG, and cardiac magnetic resonance tomography (MRT). 2D-EchoCG revealed dilation of right chambers of the heart, hypertrophy of RV anterior wall, increase of ratio of right to left ventricular end-diastolic dimensions (RV:LV), reduction of LV stroke volume, diminution of amplitude and velocity of tricuspid annular plane systolic excursion, and significant increase of myocardial performance index Tei. MRT data evidenced for lowering of RV ejection fraction. Canonical correlation was found between integral characteristic of 2D-EchoCG and integral hemodynamic characteristic (r=0.77; p=0.007). We also determined threshold values of RV: LV to be used for stratification of risk in patients with PH. In patienns with PH calculation of simple 2D-EchoCG parameters provides information important for determination of disease severity, selection of optimal method of treatment, and monitoring of patients condition.

A paradigm of galvanic vestibular stimulation diminishes the soleus muscle H-reflex in healthy volunteers.

In this study, we explored how galvanic vestibular stimulation can modify the soleus H-reflex (Hoffman reflex), that is, the excitability of the spinal cord circuits, in healthy humans. Our aim was to demonstrate H-reflex amplitude modulation caused by changing the duration and the intensity of the anodal galvanic vestibular stimulation. Therefore, we measured H-reflex before and after applied vestibular stimulation. This study was conducted in Rehabilitation Clinic, Belgrade, Serbia. The measurements were performed on 5 male volunteers aged 22-30 years. Anodal galvanic stimulation was applied on the right mastoid in prone position. H-reflex was elicited by nervus tibialis stimulation and measured from the right soleus muscle. In three subjects, trains of weak and strong galvanic stimuli (1, 5 and 9) were applied. In two subjects, only a train of 9 strong stimuli was applied. A statistically significant decrease of the H-reflex amplitude after anodal galvanic stimulation was demonstrated in all subjects. The percentage of H-reflex amplitude diminution was between 6 and 18 in subjects with weak and strong stimuli and 5 and 6 in subjects with only 9 strong stimuli. We intend to use this paradigm of stimulation to explore whether the vestibulospinal function exists after spinal cord injury (SCI). If it exists, it can be used to influence the preserved spinal cord circuits after SCI. One of the authors (Nadica Miljković) was partly supported by the Ministry of education, science and technological development, Republic of Serbia, grant OS175016.

Effects of Horizontal Geometrical Spreading on the Parameterization of Orographic Gravity Wave Drag. Part II: Analytical Solutions

Abstract Effects of horizontal geometrical spreading on the amplitude variation with height of linear three-dimensional hydrostatic orographic gravity waves (OGWs) are quantified via relevant simplifications to the governing transform relations, leading to analytical solutions. The analysis is restricted to elliptical Gaussian obstacles with principal axes aligned parallel and perpendicular to unidirectional shear flow and to vertical displacement and steepness amplitudes, given their relevance to OGW drag parameterizations in global models. Two solutions are derived: a “small l” solution in which horizontal wavenumbers l orthogonal to the flow are taken to be much smaller than those parallel to the flow, and a “single k” solution in which horizontal wavenumbers k parallel to the flow have a single mean value. The resulting analytical relations, valid for arbitrary vertical profiles of upstream winds and stability, depend only on the obstacle’s elliptical aspect ratio β and a normalized height coordinate incorporating wind and stability variations. These analytical approximations accurately reproduce the salient features of the exact numerical transform solutions. These include monotonic decreases with height that asymptotically approach z−1/2 forms at large z and strong β dependence in amplitude diminution with height. Steepness singularities close to the surface are shown to be a mathematical consequence of the Hilbert transform approach to deriving complex wavefield solutions. These approximate analytical solutions for horizontal geometrical spreading effects on wave amplitude highlight the importance of this missing physics for current parameterizations of OGW drag and offer an accurate and efficient means of incorporating some of these omitted effects.

Children With Autism Show Reduced Somatosensory Response: An MEG Study

The neural underpinnings of sensory processing differences in autism remain poorly understood. This prospective magnetoencephalography (MEG) study investigates whether children with autism show atypical cortical activity in the primary somatosensory cortex (S1) in comparison with matched controls. Tactile stimuli were clearly detectable, and painless taps were applied to the distal phalanx of the second (D2) and third (D3) fingers of the right and left hands. Three tactile paradigms were administered: an oddball paradigm (standard taps to D3 at an interstimulus interval (ISI) of 0.33 and deviant taps to D2 with ISI ranging from 1.32 s to 1.64 s); a slow-rate paradigm (D2) with an ISI matching the deviant taps in the oddball paradigm; and a fast-rate paradigm (D2) with an ISI matching the standard taps in the oddball. Study subjects were boys (age 7-11 years) with and without autism disorder. Sensory behavior was quantified using the Sensory Profile questionnaire. Boys with autism exhibited smaller amplitude left hemisphere S1 response to slow and deviant stimuli during the right-hand paradigms. In post-hoc analysis, tactile behavior directly correlated with the amplitude of cortical response. Consequently, the children were re-categorized by degree of parent-report tactile sensitivity. This regrouping created a more robust distinction between the groups with amplitude diminution in the left and right hemispheres and latency prolongation in the right hemisphere in the deviant and slow-rate paradigms for the affected children. This study suggests that children with autism have early differences in somatosensory processing, which likely influence later stages of cortical activity from integration to motor response.

In vivo characterization of the vestibulo-cochlear nerve motion by MRI

The motion of the vestibulo-cochlear nerve (VCN) was quantified at the level of the cerebello-pontine angle in 28 healthy volunteers enrolled in a prospective study performed on a 3T MRI scanner. A phase contrast MRI (PCMRI) sequence was used. The VCN was divided into a cisternal part and a meatic part, both of which were measured for motion in the cranio-caudal (CC) and antero-posterior (AP) directions. Motion was cardiac-cycle-dependent in these two directions. The meatic VCN motion was delayed compared to the cisternal VCN motion. In the CC direction, the mean amplitude of the cisternal VCN motion was twice larger than the mean amplitude of the meatic VCN motion (0.37+/-0.14 mm versus 0.17+/-0.08 mm). In the AP direction, the mean amplitude of the cisternal VCN was 0.19+/-0.08 mm versus 0.16+/-0.14 mm for the meatic VCN. We used an "oscillating string" to explain the VCN motion. Reproducibility tests have shown small variations in measurements of the CC motion. PCMRI can be used to assess the VCN motion at the level of the cerebello-pontine angle.

A propagation model for the internal solitary waves in the northern South China Sea

A two‐dimensional, regularized long‐wave equation model is developed to study the dynamic mechanisms of the propagation and evolution of the internal solitary waves (ISWs) in the northern South China Sea (SCS). It is shown that the bottom topography would cause the polarity reversal of ISWs, the change of the local wave crestline shape, and some diminution in wave amplitude; even if the ISWs are induced at the small sill channel along the Luzon Strait, they could propagate westward with their crestlines covering a large area in the latitudinal direction in the northern SCS. When there are two trains of ISWs propagating from the same source site with a time lag but different amplitudes of initial solitons, the latter train of ISWs with a larger amplitude may catch then swallow the former one with a smaller amplitude, and the wave amplitude of the merged ISW train decreases while the wave number increases. When there are two trains of ISWs propagating from the different source sites at the same time with the same amplitude of initial solitons, the crestlines of the two ISW trains may meet and a new leading soliton is induced at the connection point. Once the ISW trains collide with the island, before the island, a weak ISW train is reflected; behind the island, the former crestlines of the ISW train are torn by the island into two new trains, which may reconnect after passing around the island. The propagation direction, the wave amplitude, and the reconnection point of the new merged ISW train behind the island depend on the relative orientation of the original soliton source site to the island.