Saltwater intrusion in the Lower Chao Phraya River (LCPYR) is a significant national concern for Thailand, requiring a thorough understanding and the development of effective prediction systems for current and future management. This study investigates the key drivers influencing saltwater intrusion in the LCPYR. Cross-wavelet analysis was applied to examine the interactions between tidal forces, drought conditions represented by the rolling standardized discharge anomaly (RSDA) and rolling standardized precipitation anomaly (RSPA), and salinity levels. The results reveal that saltwater intrusion in the LCPYR is controlled by two interacting mechanisms: a drought-dependent mechanism and a drought-relaxation mechanism. The drought-dependent process, driven by regional hydro-climatic variability and quantified using the RSDA, dominates sub-annual to annual salinity fluctuations. Extreme salinity peaks are primarily modulated by non-tidal sea-level anomalies, underscoring the crucial influence of sea-level oscillations. In turn, the drought-relaxation mechanism, captured by the RSPA, reflects transient wet periods that can temporarily reduce salinity levels, at times weakening the usual correlation between salinity and hydrological drought severity. The numerical model demonstrates high accuracy in simulating both hydrodynamic and salinity behaviors, validating the cross-wavelet analysis and offering a reliable approach for modeling salinity in this complex estuarine system. We revise and suggest strategies to mitigate the salinity intrusion for emergent drought periods (e.g., optimal redistribution of the diverting freshwater) and proactive/long-term solutions, e.g., using impacts of urban runoff from tributary rivers and developing a robust prediction system. These findings offer essential insights to guide management strategies and the development of prediction tools for the LCPYR and surrounding regions.

BACKGROUND AND PURPOSE:Classification of functional impairment in persons with stroke can influence treatment planning but this information is missing in the Stroke Rehabilitation Assessment of Movement (STREAM) Scale. This study aimed to establish the classification of limb mobility impairments and item difficulty of the STREAM.METHODS:Rasch analysis was conducted on the STREAM scores to examine the person and item reliability, the item difficulty, and level of impairments. A total of 240 participants were evaluated using the STREAM, the Fugl-Meyer Stroke Assessment (FM), and the Functional Ambulation Categories (FAC). The concurrent validity of the STREAM extremity (STREAM-E) category with the FM-motor category and the STREAM mobility (STREAM-M) category with the FAC category was analyzed using the Spearman rank-order correlation.RESULTS:Person reliabilities of the STREAM-E and STREAM-M were 0.92 and 0.80, respectively. High-item reliability was observed in both STREAM-E (0.97) and STREAM-M (0.99). The STREAM items "flexes hip and knee in supine" and "rolls onto side" were the easiest items, whereas the "dorsiflexes affected ankle with knee extended" item was the most difficult item. The STREAM-E category demonstrated excellent concurrent validity with the FM-motor category (ρ = 0.83) in classifying individuals with stroke into 5 groups: mild, moderate, moderately severe, severe, and very severe limb impairment. The STREAM-M category showed a moderate correlation with the FAC category (ρ = 0.71) in categorizing persons with stroke into 3 groups: mild, moderate, and severe mobility impairment.DISCUSSION AND CONCLUSIONS:Findings can be used in the assessment and treatment planning of persons with stroke.Video Abstract available for more insights from the authors (see Video, Supplemental Digital Content 1 available at: http://links.lww.com/JNPT/A373).

High variabilities in rainfall and the subsequent consequences have caused severe water-related issues for Thailand over recent decades. In this study, the factors that affect rainfall variability over Thailand were determined. The spatio-temporal structures of the monthly rainfall in Thailand between 1979 and 2018 were extracted via an empirical orthogonal function (EOF) analysis. With a unimodal temporal structure, the first EOF mode suggests the overall phenomenon governing rain characteristics in Thailand. The higher modes, consisting of bimodal temporal structures, indicate different rain phenomena in various regions. A significantly high correlation between the 3-month average of the monsoon trough index and rainfall was observed, while wet adiabatic front and convective available potential energy (CAPE) data had a moderately high correlation. Only the local front index, within the Gulf of Thailand, correlated to the rain characteristics along the east coast of southern Thailand. The cross-wavelet analysis indicated that most of the rainfall variability correlates with monsoon trough. However, the front can involve extreme events. The interannual variability of monsoon trough and rainfall with a dominant time scale between 3.0 and 6.0 years has significantly increased since 1995. Meanwhile, the intra-annual variability is more intermittent, indicating rare intensified strong tropical cyclones along the monsoon troughs in Thailand. The interannual variability of the monsoon trough and front indices also intermittently connects with the Southern Oscillation Index (SOI). However, the relationship in annual and intra-annual cycles is mostly weak. Therefore, the dependence of interannual variability of rainfall in Thailand on SOI or monsoon trough is comparable. Notably, the intra-annual rainfall variability is heavily influenced by the monsoon trough and front. This study is the first to identify the crucial factors behind the seasonal rain phenomena in Thailand. This information will benefit seasonal rainfall predictors and increase preparedness for hydro-climatic related disasters in the Indo-China region.

The influences of tropical cyclone paths and shelf bathymetry on the inducement of extreme sea levels in a regional bay are investigated. A finite volume coastal ocean model (FVCOM) has been configured for the Gulf of Thailand-Sunda Shelf. A parametric wind model is used to drive the FVCOM. The contributions of the tropical cyclone characteristics are determined through a scenario-based study. Validation based on a historical extreme sea level event shows that the model can resolve the oscillation mechanism well. The intensification of severe storm surges in the region highly depends on four factors including phase propagation of the storm surge wave determined by the landfall position, funnel effect caused by locality of the coastline, and shelf bathymetry determined by the state of mean sea level and coastline crossing angle of the storm path. The coexistence of these factors can cause particular regions e.g. the Surat Thani Bay, inner Gulf of Thailand and Ca Mau Peninsular to experience a larger surge magnitude. These areas are found to be highly related to monsoon troughs that develop during the onset and early northeastern monsoon season (October–November).

This paper proposes the gradient directional second derivative pseudo-enhancement (PEH) correction method to reduce the computed tomography (CT) attenuations of PEH soft-tissue voxels around fecal-tagging material (FTM) in CT colo-nography and the modified local roughness response estimation, which can efficiently separate air-tagging (AT) layers from air-tissue-tagging (ATT) layers. By integrating these two proposed methods into electronic colon cleansing (ECC), FTM can be effectively removed by a simple thresholding method. For subjective or clinical evaluation, a radiologist grades the quality of cleansing based on five causes of low quality cleansing. The average grade of our proposed method for clinical evaluation is 2.5714 out of 4. For objective evaluations, three cases exist: PEH correction, ECC, and visual assessment. First, PEH correction evaluation measures the success in the removal of PEH voxels with CT attenuations greater than or equal to 500 HU using the proposed PEH correction by comparing the results of this correction with the results from the existing method via CT attenuation profiles. Second, ECC is evaluated by comparing the results from applying our proposed methods with the ground truth. The results indicate that the goodness of cleansing is 0.01% and the global mean relative error is less than 0.016% with 99.99% confidence. Third, visual assessment of our ECC results confirms that soft-tissue components around FTM, especially ATT layers, are preserved.

Vibration suppression system using two hybrid oilgas DBAir shock absorbers and a roll-balancing front connecting bar is designed for a 3-m unmanned carbon-fiber catamaran, equipped with a laser scanner on the top platform. To measure actual accelerations of both catamaran hulls and top platform, two accelerometers are employed; however, gravitational acceleration must be eliminated from acceleration signals to capture pure structural acceleration/vibration. Moreover, adjustable spring stiffness and damper coefficients of the DBAir shock absorber are experimentally measured at various valve settings. Thus, natural frequency and damping ratio of a lumped-parameter base-excitation model of single shock absorber exhibits overdamped characteristics of the designed vibration suppression system. Experimental manual excitations at one hull at low frequency of 1-Hz and at high frequency of 2-Hz show acceleration/vibration reduction of the top platform by half according to both acceleration time-series signals and Power Spectrum Density (PSD) estimation in frequency-domain analysis. Using frequency-domain analysis, PSD of the top-platform vibration shows much smaller amplitude than that of the catamaran hull in wide-frequency range, when there exists hydrodynamic wave excitation at catamaran-hull with frequency of around 1 Hz. In cruising operation with small impact wave, acceleration time series reveals more than 60%-70% vibration reduction of the top laser-scanner platform comparing to the hull motion.

The ocean currents are one of the main driving forces for many vital coastal processes. Analyzing ocean current data, especially in coastal areas, can benefit the coastal ocean communities in deriving insight and knowledge on coastal ocean processes and variability. high frequency surface wave radars (HFSWRs) provide comprehensive and long range (30-100 km) observations of sea surface currents with high temporal (typically 0.25-1 hour) and spatial (typically 1-3 km) resolution. The data gathered from HFSWRs can therefore be well used to study eddy dynamics as well as variability in coastal ocean currents. However, high frequency surface wave radar (HFSWRs) are shore based remote sensing systems, and can be prone to environmental interferences resulting in observation failure. To this end, we first apply the Discrete Cosine Transform (DCT-PLS) algorithm to fill gaps in high frequency surface wave radar (HFSWR) data in the Gulf of Thailand from the Geo-Informatics and Space Technology Development Agency (GISTDA), Thailand. The DCT-PLS algorithm uses both time and space information to predict missing values. Finally, we also analyze and reveal dynamics of the coastal ocean circulation via dynamic mode decomposition (DMD) together with sparsity-promoting variant (SPV) approach in order to obtain insight into the dynamics and spatial structures of the ocean currents in the Gulf of Thailand. A comparison with EOF technique is also provided.

Background In computed tomography colonography images, electronic cleansing (EC) is applied to remove opacified residual materials, called fecal-tagging materials (FTM), using positive-contrast tagging agents and laxative to facilitate polyp detection. Methods The proposed EC, EC prop , integrates the gradient directional second derivative into material fraction model to preserve submerged soft tissue (ST) under FTM. Three-material fraction model is used to remove FTM and artifacts at air-tagging (AT) layers and T-junctions where air, ST, and FTM material meet simultaneously. Moreover, the proposed AT layer identification is used to distinguish AT layers from air-tissue-tagging (ATT) layers in order to preserve ATT layers during cleansing. The clinical evaluation on 467 3-Dimensional band view images was conducted by the abdominal radiologist using four grading levels of cleansing quality with five causes of low quality EC. The amount of the remaining artifacts at T-junctions was approximated from the results of EC prop . The results from EC prop were compared with the results from syngo.via Client 3.0 Software, EC syngo , and the fast three-material modeling, EC prev , using the preference of the radiologist. Two-tailed paired Wilcoxon signed rank test is used to indicate statistical significance. Results The average grade on cleansing quality is 2.89 out of 4. The artifacts at T-junctions from 86.94 % of the test images can be removed, whereas artifacts at T-junctions from only 13.06 % of the test images cannot be removed. For 13.06 % of the test images, the results from EC prop are more preferable to the results from EC syngo ( p <0.008). For all the test images, the results from EC prop are more preferable to the results from EC prev ( p <0.001). Finally, the visual assessment shows that EC prop can preserve ATT layers, submerged polyps and folds while EC prev can preserve only submerged folds but fails to preserve ATT layers. Conclusion From our implementation, EC prop can improve the performance of the existing EC, such that it can preserve ST, especially ATT layers and remove the artifacts at T-junctions which have never been proposed by any other methods before.

The decision of stem cells to leave the self-renewing state and select a differentiation pathway is regulated by a number of transcription factors (TFs). In this work, we employed a mathematical model to study the embryonic stem cell differentiation to primitive streak Specifically, using experimental data reported in literatures, we constructed a gene regulatory network (GRN) of TFs regulating the primitive streak commitment. The GRN consisted of three main TFs: OCT4, SOX2, and NANOG interacting with Eomesodermin (EOMES), which was the key TF controlling the formation of primitive streak The mathematical model was derived using kinetics of gene regulation in the form of system of ordinary differential equations. The results of simulations demonstrated that the model was capable of predicting the stem cell's decision.

Ocean currents are one of the most important factors in marine environment. Ocean currents affect the availability of nutrients, food and the spread of eggs and larvae for marine animals. Besides, the ocean currents are also the main driven forces for sediment transport and coastal processes which are the key factors for the coastal erosion and accretion as well as marine pollution. Thus, analyzing ocean current information, especially in shallow seas, will benefit ocean scientists in deriving new knowledge on ocean processes and variability, fishery/aquaculture scientists in incorporation the larval distribution of fish into improved management plans and management authorities in deriving and implementing more effective coastal management schemes.In this work, we first aim at simulating the ocean circulation in the Gulf of Thailand. The region is composed of complex coastlines and seafloor topography. This can result in complicated ocean currents. To this end, we employ the unstructured grid Finite-Volume Coastal Ocean Model (FVCOM) to handle such issue with its geometric flexibility capability. For the model validation purpose, we use the surface currents data measured by high frequency surface wave radar (HFSWR) from Geo-Informatics and Space Technology Development Agency (GISTDA). We have found that the RMS error shows the model output agrees with the observation well. Besides, we also investigate the overall characteristic of the simulate currents together with the observed currents as well. This is done through the Empirical Orthogonal Function (EOF). The results also indicate that the dominant characteristic of ocean currents from simulation is analogous to the observation. To sum up, these results justify that the model can be predicted and explained the behavior of ocean currents precisely and realistically. Secondly, we also analyze the EOF pattern of the ocean circulation in order to provide insight into the dynamics and spatial structure of the ocean currents in the Gulf of Thailand.

The unprecedented flood event in the central Chao Phraya basin in 2011 was a catastrophic natural disaster affecting Thai society and economic sectors. During this event massive amounts of overland flow played a major role in damaging properties and environmental systems, with typical drainage systems rather ineffective in low-lying flat lands. The capability to effectively handle flood problem under these conditions is indeed a great challenge. To achieve such a goal, hydrological management schemes need to be improved based on insightful knowledge of flood hydrodynamics. In this study, we aim to gain insight into the aforementioned issue by performing and analyzing simulation of overland flow in low-lying flat lands. The flood plain of Sam-Khok and Klong Luang districts was selected as the study area and the simulation performed with an unstructured grid shallow water model together with a high-fidelity topographic data (LIDAR). The simulation results have been validated with field data (water trace height). The major hydrodynamic mechanisms such as flow patterns, flow magnitudes are characterized and the effective discharge quantified.

A numerical simulation is used to determine the effective resonance period, quality factor Q and linear friction coefficient and mechanism of tide and storm surge in the Gulf of Thailand. The results indicated that the resonance response is triggered by the forced wave with the period of 20.25 hours. The Q factor and linear friction coefficient are approximately 3.15 and 2.76×10−5ms−1, respectively. The gulf is regarded as a moderately dissipative system, which may yield small amplification for the oscillating forced wave. The resonance structure of the basin can play an important role in spatial distribution and amplification of tidal waves in the Gulf of Thailand and nearby area. Distance from the effective resonance period and the corresponding Q factor can be employed in characterizing of tidal amplification in the gulf. The study found that phase difference in the incoming tidal waves can induce the distortion of a nodal band to the normal mode analysis results. The resonance in the north–south direction is the principal mechanism to control tidal waves, specifically for the upper part of the gulf (the Gulf of Thailand). However, significant effect of resonance in the west–east direction on the amplification of tidal waves near the southern part of the gulf (Vietnam, Malaysia and Singapore coast) may be pronounced. From the reproduced historic storm surge and hypothetical results, the spatial distribution of storm surge elevation and the response ratio are in good agreement with the resonance mode and Q factor of the basin. Individually, the contribution of resonance factor to induce severe storm surge (positive surge) tends to be insignificant. Conversely, the interaction process between the disturbance system and the propagating surge wave in the gulf can induce large positive surge near the landfall location significantly.

In this study, we have applied normal mode analysis on recent past storm events in the Gulf of Tonkin and the Leyte Gulf. The normal modes for each location are obtained from the previously developed unstructured normal mode decomposition solver based on the finite element method. The analysis of the two recent past storm events using the normal modes derived from the solver has been investigated in these two locations. The first event is tropical cyclone NARI (2013) in the Gulf of Tonkin, Vietnam and the second one is the super typhoon HAIYAN (2013) in the Leyte Gulf, the Philippines. Apart from obtaining the site-specific storm hazard summary through the normal mode shape, the study also aims to gain a deeper understanding on how normal modes contributed to the overall surge from the analysis of these past storm events.

The vertical jump is an essential skill used in a volleyball match but the information on the principal muscles used is incomplete. The present study aimed to identify the major muscles used in vertical jump by employing the principal component analysis (PCA) and the analysis of area under the curve (AUC). Ten elite female volleyball players (NV) and 10 female sedentary controls (SC) participated in this study. Each subject performed 2 jumping styles: squat jump and vertical stop jump. Electrical activities from thirteen muscles in the arm, trunk, and leg were recorded with electromyography (EMG). EMG data were processed using PCA and AUC methods, and the major muscles were identified by the first mode of PCA and the highest AUC. Our results showed that the PCA method was more sensitive than the AUC method for classifying the group differences in major muscles during jumping. Distinct activation of the erector spinae may explain the better performance in the NV compared to the SC, who preferentially used other trunk muscles in jumping. Our observation indicates that the PCA method is an appropriate analytical tool to differentiate the major muscles used in jumping between elite athletes and sedentary controls. This finding provides important information for designing training programmes especially for vertical jumps in sports.

In this study, we have developed an unstructured normal mode decomposition solver based on the finite element method for the purpose of normal mode analysis on natural basins. The normal mode analysis can be used to provide the site-specific storm hazard summary such as storm risk for a given basin. This information can provide a useful guideline during the storm events. The analysis of the two past storm events using the normal modes derived from the solver has been demonstrated in two different locations. The first event is tropical cyclone Linda (1997) in the Gulf of Thailand and the second one is tropical cyclone Melor (2009) in the Ise Bay, Japan. The analysis reveals a relation of the storm forward speed and the storm path to the spatial distribution of leading normal modes. We believe that our results can be used for the analysis of past storm events, and may be applied to future storm events.

This paper proposes a new method to enhance the intensities of the contents in the vicinity of the edges by integrating directions of three multi-scale vector flows with directional anisotropic diffusion.

This paper investigates a new approach for efficiently calculating nozzle thrust based on a reduced order model formed by the proper orthogonal decomposition (POD) technique. The investigation has been done on the nozzle of MK66 rocket motor as a prototype problem. Here, the focus is on the thrust response in or near the design condition. It was found that the proposed method performs exceptionally well even with a few POD basis functions extracted from limited number of flow snapshots. Various interpolation techniques for estimating the dynamic of the reduced order model have been investigated as well. In the current study, the results suggested that there is no significant difference in the thrust estimation from those techniques.