Burapha Science Journal

Estimation of the Population Mean of the XLindley Distribution with Applications to Water Quality Data

Chanyanut Polkampon, Sukrit Jantap, Patarawan Sangnawakij — Tue, 01 Sep 2026 00:00:00 +0700

Background and Objectives: The XLindley distribution is a continuous probability distribution with a single positive parameter, developed from the exponential and Lindley distributions. It is suitable for modelling time-to-event data, chemical decay processes, and product lifetimes. However, no previous study has investigated the estimation of the population mean for this distribution. Therefore, this study aims to investigate parameter estimation methods for the population mean of the XLindley distribution, evaluate the performance of the estimators, and apply the proposed methods to real data.

Methodology: The point estimators for the parameter of the XLindley distribution considered in this study include the method of moments, which is based on the relationship between population and sample moments; the maximum likelihood method, which determines the parameter value that maximizes the likelihood function; and the bootstrap method, which uses resampling with replacement to approximate the sampling distribution of the estimator. For interval estimation of the population mean, the large-sample approximation method, the Wald-type method based on the asymptotic normal distribution and Fisher information, and the percentile bootstrap method are employed to construct confidence intervals. The performance of these methods is evaluated in terms of bias and mean squared error for point estimation, as well as coverage probability and average confidence interval length for interval estimation. A simulation study is conducted under various scenarios with sample sizes of 10, 20, 30, 50, 100, and 200, and population mean values of 0.02, 0.1, 0.21, 1.25, 2.89, and 18.26 to reflect different distributional characteristics and a wide range of possible situations. Afterward, the proposed methods are applied to estimate the population mean using two real datasets following the XLindley distribution.

Main Results: The point estimator obtained from the maximum likelihood method performs comparably to that obtained from the method of moments in terms of bias and mean squared error, whereas the bootstrap estimator exhibits higher bias than the other estimators considered in this study. For interval estimation, the Wald method provides coverage probabilities close to the nominal confidence level of 0.95 and yields relatively short average interval lengths when the mean of the XLindley distribution exceeds 0.10. If the mean is less than or equal to 0.10, the large-sample approximation method based on the normal distribution provides coverage probabilities closer to 0.95 than the alternative methods. In contrast, the percentile bootstrap method produces coverage probabilities lower than the nominal level in several scenarios. When the proposed methods are applied to water quality data in Thailand, the estimated mean of biological oxygen demand from water sources in 10 districts with the highest numbers of industrial factories in Bangkok in 2024 was 8.823 mg/L, with a 95% confidence interval of (5.783, 16.924). Meanwhile, the estimated mean arsenic concentration from eight monitoring stations along the Kok River in Chiang Rai in 2025 was 0.017 mg/L, with a 95% confidence interval of (0.005, 0.029).

Conclusions: Although the maximum likelihood estimator and the method of moments estimator exhibit comparable performance in the simulation study, the maximum likelihood estimator possesses the invariance property, which is widely useful in statistical inference theory. Therefore, this estimator is recommended for point estimation of the population mean of the XLindley distribution. For interval estimation, the choice of method should depend on the mean of the XLindley-distributed data in order to obtain the confidence interval with efficient coverage performance. In application, these estimation methods can be applied to real-world data analysis. The findings from the real datasets considered in this study indicate that the average biological oxygen demand in Bangkok was below 20 mg/L, implying that the water sources in this area are within the safety standard established by the World Health Organization. In contrast, the average arsenic concentration in the Kok River in Chiang Rai during the study period exceeded 0.01 mg/L, which does not meet the recommended standard and may adversely affect living organisms and aquatic ecosystems.

Development of a Spatial Model for Estimating Aboveground Carbon in Mixed Deciduous and Dry Dipterocarp Forest Using Remote Sensing Data: A Case Study of Wang Samran Community Forest, Lampang Province

Tue, 01 Sep 2026 00:00:00 +0700

Background and Objectives: Forest ecosystems play an important role in Carbon stock and climate change mitigation because forests can accumulate aboveground biomass and store large amounts of carbon in living vegetation. Therefore, accurate estimation of aboveground biomass and carbon storage is essential for forest resource monitoring, sustainable forest management, and the development of community-level carbon credit mechanisms. However, assessment based solely on field data is time-consuming and labor-intensive. Consequently, Sentinel-2 satellite imagery, which provides multiple spectral bands and suitable spatial resolution for vegetation analysis, has been applied in this study. The objective of this research was to estimate aboveground biomass and aboveground carbon storage in the Mixed Deciduous and Dry Dipterocarp Forest of Ban Wang Samran Community Forest, Lampang Province, by integrating field data with Sentinel-2 imagery in order to analyze the relationships among spectral variables, develop an aboveground biomass estimation model, and compare satellite-derived results with field-based data.

Methodology: This study was conducted in Ban Wang Samran Community Forest, Lampang Province. Field data were collected from 17 sample plots and used to calculate aboveground biomass by applying allometric equations, while aboveground carbon was estimated using a constant factor of 0.47. These field-derived values were used as reference data for model development and validation. At the same time, Sentinel-2 satellite imagery covering the study area was processed to extract reflectance values from vegetation-related bands, including the blue, green, red, and near-infrared bands. In addition, 12 vegetation indices were calculated, namely EVI2, GNDVI, MSAVI, NDMI, NDRE, NDVI, SAVI, SR-RE, SR, VARI, MTVI2, and RTVIcore. Relationships between field-based carbon values and satellite-derived variables were then analyzed using linear regression, and the most suitable variables were selected based on the coefficient of determination (R²) for the development of a multiple linear regression model to estimate aboveground biomass. Furthermore, values derived from field measurements and satellite data were compared using inferential statistics, a paired t-test at the 95% confidence level, and Pearson’s correlation coefficient.

Main Results: Field survey results revealed that the Mixed Deciduous and Dry Dipterocarp Forest in the study area had a moderate potential for biomass accumulation and carbon storage. The mean aboveground biomass was 71.62 t/ha, with a minimum of 52.43 t/ha and a maximum of 140.52 t/ha. Mean aboveground carbon storage was 33.66 tC/ha, ranging from 24.64 to 66.04 tC/ha. Analysis of the relationship between aboveground carbon storage and Sentinel-2 variables showed that VARI was the best single predictor, with the regression equation y = 0.0009x + 0.0109 and an R² value of 0.28. The next best predictors were NDMI, MTVI2, and the red band, each with an R² of 0.12. Some variables, such as SR-RE, NDRE, and RTVIcore, could not explain the variation in the data. To improve estimation performance, a multiple linear regression model was developed using VARI and SR, yielding the equation: AGB = 409.313 + 996.771(VARI) - 165.375(SR), with an R² of 0.64. Comparison between field-based values and Sentinel-2-derived estimates showed that the two approaches produced very similar mean values. The paired t-test indicated no statistically significant difference at the 95% confidence level, and Pearson’s correlation coefficient was r = 0.80, indicating a strong positive relationship between the two datasets.

Conclusions: The findings of this study highlight the effectiveness of integrating Sentinel-2 satellite imagery with field-based inventory data for estimating aboveground carbon storage in the Mixed Deciduous and Dry Dipterocarp Forest of Ban Wang Samran Community Forest, Lampang Province. Although individual spectral variables had limitations in explaining data variation, combining VARI and SR significantly improved model performance. The statistical results, which showed no significant difference between field-based and Sentinel-2-derived values, together with the high correlation coefficient, support the potential of Sentinel-2 data for carbon estimation at the sample plot level. Therefore, the developed model can serve as a practical tool for sustainable monitoring and assessment of community forest resources and for supporting the development of local carbon credit initiatives.

Toxicity of 2,4-D-Dimethylammonium Based-Herbicide in Nile Tilapia (𝙊𝙧𝙚𝙤𝙘𝙝𝙧𝙤𝙢𝙞𝙨 𝙣𝙞𝙡𝙤𝙩𝙞𝙘𝙪𝙨)

Tue, 01 Sep 2026 00:00:00 +0700

Background and Objectives: 2,4-D-dimethylammonium is a widely used herbicide for controlling broadleaf weeds and sedges in aquatic environments. It is also utilized as a plant growth regulator in dicotyledonous crops to enhance crop productivity. In Thailand, it is one of the most extensively imported herbicides, ranking third among agricultural chemicals in terms of import volume. Owing to its widespread application, residues of 2,4-D-dimethylammonium are frequently detected in the environment, particularly in soil and surface waters. This study aimed to evaluate the toxicity of 2,4-D-dimethylammonium in Nile tilapia (Oreochromis niloticus), a freshwater fish species widely distributed throughout Thailand. Specifically, the study investigated acute toxicity, cumulative mortality, morphological alterations, oxidative stress responses, hematological changes, histopathological lesions in major organs, alterations in protein profiles, and acetylcholinesterase (AChE) activity and protein expression, which are recognized biomarkers of exposure to 2,4-D-dimethylammonium. The findings provide new insights into the toxicological mechanisms underlying 2,4-D-dimethylammonium-induced toxicity in Nile tilapia.

Methodology: Adult Nile tilapia weighing 150–200 g were used in this study. Acute toxicity was evaluated by exposing fish to five concentrations of 2,4-D-dimethylammonium (33.60, 42.00, 50.40, 58.80, and 67.20 mg/L), together with an untreated control group. Cumulative mortality was recorded at 24, 48, 72, and 96 h after exposure. The median lethal concentration (LC₅₀) was estimated using probit analysis. To investigate sublethal toxicity, fish were exposed to a non-lethal concentration of 2,4-D-dimethylammonium for 28 days, and samples were collected on days 0, 7, 14, 21, and 28. Hematological parameters, including hemoglobin concentration, hematocrit, erythrocyte count, total leukocyte count, and differential leukocyte count, were determined to assess physiological and immunological responses. Morphological abnormalities were documented throughout the exposure period. Oxidative stress was evaluated by measuring the activities of the antioxidant enzymes: superoxide dismutase (SOD), catalase (CAT), and glutathione S-transferase (GST). Histopathological examinations of the gills, liver, intestine, and stomach were performed to assess tissue damage. In addition, protein profiles, acetylcholinesterase (AChE) activity, and AChE protein expression were analyzed using SDS-PAGE and Western blotting.

Main Results: The results demonstrated that cumulative mortality increased with increasing herbicide concentration and exposure duration. The highest exposure concentration (67.20 mg/L) resulted in 50% cumulative mortality after 96 h. Sublethal exposure induced progressive morphological abnormalities, including scale discoloration, fin base swelling, fin erosion, and hemorrhagic lesions, all of which became more severe with prolong exposure. Oxidative stress analysis revealed significant increases in SOD, CAT, and GST activities with increasing exposure times, demonstrating an elevated production of reactive oxygen species and activation of the antioxidant defense system. Hematological analysis showed significant reductions (p < 0.05) in hematocrit and eosinophil counts, suggesting physiological stress and impaired immune function. Histopathological alterations were evident from days 7–14 after exposure. Gill tissues exhibited epithelial hyperplasia and lamellar aneurism, whereas liver tissues showed hepatocellular vacuolation and degeneration. Intestinal tissues displayed microvillar lesions, epithelial damage, and villus swelling, while stomach tissues exhibited epithelial erosion. Protein profiling and biomarker analyses of muscle tissue further revealed progressive decreases in AChE activity, total protein levels, and AChE protein expression with prolonged exposure.

Conclusions: The findings demonstrate that exposure to 2,4-D-dimethylammonium adversely affects multiple physiological systems in Nile tilapia, including external morphology, hematological homeostasis, oxidative stress, tissue integrity, and cholinergic nervous system function. The observed hematological impairment, oxidative stress, histopathological damage, and suppression of AChE activity collectively demonstrate the systemic toxicity of this herbicide. This study highlights the ecological risks associated with 2,4-D-dimethylammonium contamination
in aquatic environments and underscores the need for responsible herbicide management, continuous monitoring of water quality, and the development of sustainable strategies to prevent chemical pollution. Collectively, this study provides valuable evidence for environmental risk assessment and advances scientific understanding of herbicide-induced toxicity in freshwater fish.

An Improved Differential Evolution Algorithm for Solving Systems of Nonlinear Equations

Watchara Wongsa — Tue, 01 Sep 2026 00:00:00 +0700

Background and Objectives: Systems of nonlinear equations are considered extremely important optimization problems in the computational field. They frequently appear and play a crucial role in many different practical fields, such as applied science, engineering, and economic modeling. Generally, these problems are characterized by their high nonlinearity and the presence of numerous local minima. Because of these challenging characteristics, traditional derivative-based methods often struggle to solve these problems. Specifically, they easily get stuck in local minima and depend heavily on initial values to function correctly. To overcome these limitations, researchers apply differential evolution (DE), which is widely recognized as a powerful global optimization method. However, the basic DE algorithm still faces certain critical challenges. It often suffers from slow convergence speed, premature convergence, or complete search stagnation in highly complex problems. These issues mainly result from the use of inappropriate control parameters and ineffective mutation strategies during the search process. Therefore, this research proposes an improved differential evolution algorithm, named DECM. The main objective is to successfully solve six complex real-world systems of nonlinear equations with higher accuracy and a faster convergence speed compared to existing techniques.

Methodology: To achieve these goals, this research improves the standard differential evolution (DE) algorithm in two main parts. The first part focuses on setting appropriate control parameters that are randomly generated within appropriate ranges. These parameter settings help the system maintain a balance between population diversity and convergence speed. The second part applies a fitness-sorted mutation strategy. This process sorts randomly selected vectors based on their objective function values in ascending order. After sorting, it forces the vector with the best fitness to serve as the base vector. This approach effectively guides the search direction toward the most promising regions. To evaluate its actual performance, the DECM algorithm is tested on five real-world nonlinear systems of equations. These problems include Neurophysiology, Robot kinematics, Economics modeling, Chemical equilibrium, Combustion, and Automotive steering. The experiments use two stopping criteria based on existing literature: Value-To-Reach (VTR) and the maximum number of function evaluations (Max nf). Finally, the results of DECM are directly compared with DE59-50, DE59-100, DE-R, and PSO-based methods.

Main Results: Under the VTR criterion, the proposed DECM algorithm achieves a perfect 100% success rate across all five problems. Furthermore, it requires a lower mean of function evaluations (Mean nf) than the compared methods in most cases. For example, in Problem 5, DECM uses an average of only 34009.80 evaluations to find a solution. This number is significantly lower than the other methods, whereas DE59-50 completely fails to solve this problem. Additionally, DECM produces lower standard deviations than the comparative methods in almost all scenarios. The experimental results indicate that the proposed algorithm achieves rapid convergence and maintains stability in finding the solution. Under the Max nf criterion, DECM consistently yields lower average best objective function values than all compared methods, demonstrating significant improvements in Problem 1. However, Problem 3 presents an exception. In this problem, DECM successfully finds the same minimum value as the compared methods, but its average value remains higher. The experimental results under this criterion demonstrate that the DECM method provides accurate and stable solutions across all test problems, except for Problem 3, where the proposed method occasionally fails to avoid converging to local minima during some experimental runs.

Conclusions: In summary, this research successfully presents an improved differential evolution algorithm called DECM for solving real-world systems of nonlinear equations. The proposed algorithm combines appropriate control parameters with a fitness-sorted mutation strategy. These implemented strategies effectively balance global exploration and local exploitation. The proposed algorithm has a relatively simple structure, facilitating straightforward implementation. At the same time, it provides high accuracy and fast convergence directly to the global optimum. However, as the performance evaluation is limited to a set of six test problems, the proposed algorithm is considered a promising tool for solving complex systems of nonlinear equations within similar contexts. Future research should expand the testing to include problems in other domains or higher-dimensional systems to further validate the generalization capability of the algorithm.

𝘼𝘾𝙀 Genetic Polymorphism and Body Composition Characteristics in Collegiate Runners

Tue, 01 Sep 2026 00:00:00 +0700

Background and Objectives: Contemporary sports science recognized that sports performance is determined by a complex interaction among environmental conditions, training status, and genetic factors. Among the genetic markers that have received considerable attention, the Angiotensin-converting enzyme (ACE) gene is one of the most extensively studied genetic markers in sports. It plays a crucial role in the renin-angiotensin system, which regulates cardiovascular homeostasis. The ACE Insertion/Deletion (I/D) polymorphism arises from the presence (Insertion, I) or absence (Deletion, D) of a 287-base pair sequence within intron 16 on chromosome 17, and this variation can influence ACE enzyme activity in the body. Previous studies have demonstrated an association between the ACE I/D polymorphism and athletic physical performance; the I allele tended to correlate with endurance-oriented traits and muscle fatigue resistance, whereas the D allele was frequently associated with power, strength, and muscle hypertrophy. However, most studies of ACE genotypes have focused on elite athletes or non-Thai populations, leaving the genetic profile of Thai collegiate runners unexplored. Accordingly, this study aimed to examine the genotype distribution of the ACE gene in regularly trained university runners and to explore its relationship with body composition.

Methodology: This study used a cross-sectional design and involved 24 runners from Burapha University, consisting of 18 males and 6 females, with a mean age of 20.17 ± 1.24 years. All participants were regularly trained university runners. Body composition was assessed using bioelectrical impedance analysis to obtain body mass index (BMI), percent body fat, and skeletal muscle mass. DNA samples were collected from buccal epithelial cells using buccal swabs and subsequently extracted using a DNA extraction kit. The ACE I/D genotype was analyzed via polymerase chain reaction (PCR) utilizing gene-specific primers. The resulting PCR products were separated by agarose gel electrophoresis to visualize genotype patterns. To confirm the accuracy of genotype identification, nucleotide sequencing was performed. Genotype frequencies were tested for Hardy–Weinberg equilibrium (HWE), and the associations between ACE genotype and body composition variables were analyzed using non-parametric statistical techniques appropriate for small sample sizes, with the Kruskal–Wallis H test at a significance level of 0.05. Descriptive statistics were reported as mean ± standard deviation, while genotype distribution was expressed as frequency and percentage.

Results: The results revealed that the ACE genotype distribution in Thai collegiate runners deviated from the Hardy-Weinberg equilibrium. The heterozygous ID genotype was observed most frequently, accounting for 75.0% of the sample, while both homozygous II and DD genotypes were found in equal proportions of 12.5% each. Statistical analysis revealed no significant differences in BMI, body fat percentage, or skeletal muscle mass among the genotype groups (p > 0.05). However, the descriptive results showed a consistent trend. The II genotype group exhibited the highest mean values for BMI, percent body fat, and skeletal muscle mass, followed by the DD group, and then the ID group. These findings suggest that while no significant association was detected in this relatively small sample, genotype-related tendencies may still exist and warrant further investigation in larger populations.

Conclusions: In conclusion, Thai collegiate runners showed an unusually high frequency of the ACE ID genotype. This specific genotype may represent a genetic profile that confers advantages in training adaptations, competition, or overall athletic performance at the university level. Although no statistically significant associations between ACE genotype and body composition were detected, the II genotype group showed a tendency toward greater BMI, adiposity, and skeletal muscle mass. These findings highlight the importance of conducting population-specific genetic studies among Thai athletes, as such information may contribute to a better understanding of sport-related genetic variation. In the future, larger and more diverse samples will be necessary to clarify the biological and performance-related roles of the ACE I/D polymorphism. Ultimately, this line of research may support the development of personalized training and conditioning programs to individual genetic profiles, thereby enhancing athletic preparation and performance optimization.

Histology and Ultrastructure of the Vitelline Gland of the Pancreatic Fluke 𝙀𝙪𝙧𝙮𝙩𝙧𝙚𝙢𝙖 𝙥𝙖𝙣𝙘𝙧𝙚𝙖𝙩𝙞𝙘𝙪𝙢

Jantanee Boonmameepool , Jirat Boonmameepool — Tue, 01 Sep 2026 00:00:00 +0700

Background and Objectives: The vitelline gland is an essential reproductive structure in trematodes, with vitelline cells contributing to eggshell formation and providing nutrients and other components required for embryonic development. During vitellogenesis, developing vitelline cells undergo a series of morphological and ultrastructural changes associated with the synthesis and accumulation of specific cytoplasmic inclusions, particularly eggshell globules and lipid droplets. The composition and organization of these inclusions vary among digenean species and may reflect differences in reproductive strategies and patterns of egg development. In trematodes that produce embryonated eggs, vitelline cells may exhibit specialized structural characteristics associated with embryonic development prior to egg release from the definitive host. However, detailed information on the ultrastructural differentiation of vitelline cells in trematodes that produce embryonated eggs remains limited. In particular, the structural relationship between developing vitelline cells and their associated nurse cells has not been extensively characterized. To address this gap, this study investigated the histological organization and ultrastructure of the vitelline gland of Eurytrema pancreaticum, an embryonated egg-producing digenean trematode, with particular emphasis on the sequential differentiation of vitelline cells and the structural characteristics of nurse cells during vitellogenesis.

Methodology: Vitelline glands from five adult E. pancreaticum specimens were processed for resin embedding and examined using light microscopy (LM) and transmission electron microscopy (TEM). Semithin sections were examined by LM to characterize the organization and distribution of vitelline follicles. Ultrathin sections were examined by TEM to characterize the ultrastructural features of vitelline cells at different developmental stages and their associated nurse cells. Vitelline cells were classified into developmental stages based on their cytoplasmic organization and the presence, size, and distribution of characteristic cytoplasmic inclusions. Ultrastructural assessment focused oneggshell globule clusters, lipid droplets, glycogen particles, glycan vesicles, cellular junctions, and the association between vitelline cells and nurse cells.

Main Results: The vitelline gland consisted of numerous follicles arranged in two lateral groups on either side of the parasite. Each follicle contained developing vitelline cells surrounded by flattened nurse cells. Based on their ultrastructural characteristics, vitelline cells were classified into four developmental stages: immature, intermediate type I, intermediate type II, and mature cells. Immature vitelline cells exhibited relatively undifferentiated cytoplasm with early development of characteristic inclusions. During intermediate differentiation, eggshell globules progressively appeared, increased in number and size, and became organized into distinct clusters. Lipid droplets also accumulated progressively throughout development. Intermediate type II cells showed more prominent eggshell globule clusters and increased lipid accumulation, indicating further cellular differentiation. Mature vitelline cells contained large, well-developed eggshell globule clusters and abundant lipid droplets, representing the most advanced stage of vitelline cell differentiation. In contrast, glycogen particles and glycan vesicles were not observed at any developmental stage examined. Nurse cells exhibited extensive apical invaginations and close associations with adjacent developing vitelline cells. Gap junctions were observed between nurse cells and developing vitelline cells, suggesting intercellular communication and functional interactions during vitellogenesis. The coordinated development of eggshell globules and lipid inclusions, together with the close association between nurse cells and developing vitelline cells, indicates that vitelline cell differentiation is an organized process involving interactions between developing and supporting cells.

Conclusions: This study provides detailed histological and ultrastructural information on vitelline cell differentiation in E. pancreaticum. Vitellogenesis was characterized by the progressive formation and enlargement of eggshell globule clusters and the accumulation of lipid droplets, whereas glycogen particles and glycan vesicles were absent throughout the developmental sequence. The extensive apical invaginations and gap junctions observed between nurse cells and developing vitelline cells further indicate close structural and functional interactions during vitellogenesis. The distinctive combination of eggshell globule development, lipid accumulation, and nurse cell association may be related to the reproductive strategy of this embryonated egg-producing trematode. These findings contribute to the understanding of reproductive biology in E. pancreaticum and provide useful ultrastructural information for comparative studies of vitellogenesis and eggshell formation among digenean trematodes.

Forecasting Future Land Use and Land Cover Changes Using Spatial Modeling: A Case Study of Phitsanulok Province

Sunisa Tienkaew, Niti Iamchuen — Tue, 01 Sep 2026 00:00:00 +0700

Background and Objectives: Rapid urban expansion and infrastructure development along economic corridor frameworks in Phitsanulok Province, which lies at the intersection of the East-West Economic Corridor (EWEC) and the North-South Economic Corridor (NSEC), have continuously driven land-use and land-cover (LULC) changes in the province. These ongoing changes directly affect habitat quality and ecosystem integrity. This study aimed to (1) analyze the spatiotemporal dynamics of LULC change in Phitsanulok Province across three time points, namely 2007, 2014, and 2021; (2) forecast future LULC patterns to the year 2028 using the CA–Markov model; and (3) assess the impacts of land-use change on habitat quality and habitat degradation using the InVEST Habitat Quality module.

Methodology: Satellite imagery was analyzed using Landsat 5 TM data for 2007 and Landsat 8 OLI/TIRS data for 2014 and 2021, both at 30-meter spatial resolution, obtained from the USGS Earth Explorer archive. Dry-season imagery was selected to minimize interference from cloud cover. Land use was classified into five categories—agricultural land, forest land, urban and built-up area, miscellaneous land, and water body—using the Maximum Likelihood Classification (MLC) technique. The CA-Markov model was then validated by using the 2007 and 2014 LULC data to simulate a land-use map for 2021, which was compared against the actual reference map from the Land Development Department. Once validated, the 2014–2021 transition probability matrix was applied to forecast land use for 2028. In parallel, habitat quality and habitat degradation were assessed using the InVEST Habitat Quality module, incorporating four threat factors—urban and built-up areas, agricultural land, major roads, and railways—with parameters assigned following a literature-based approach drawn from the InVEST User's Guide and relevant tropical-context studies.

Main Results: The CA–Markov model demonstrated satisfactory predictive performance for land-use forecasting, achieving an Overall Accuracy of 0.87 and a Kappa coefficient of 0.79, indicating a high level of agreement between the simulated and actual land-use maps. The 2028 projection showed that urban and built-up areas were expected to increase from 6.08% to 6.42% of the provincial area, while agricultural land was projected to expand by 6.41%, and forest land showed a slight recovery of 0.57%. In contrast, miscellaneous land was projected to decline sharply, by as much as 40.51%, indicating that this land type functioned as the primary reservoir absorbing conversion into both agricultural and urban built-up areas as the province continued to develop. Assessment using the InVEST Habitat Quality model further showed that overall habitat quality declined from 0.544 in 2007 to 0.528 in 2028, while the corresponding habitat degradation index rose from 0.137 to 0.154 over the same period. Spatially, areas experiencing high habitat degradation expanded outward from the urban core toward peri-urban zones and the surrounding agricultural areas, particularly along the major road network and the transitional zones bordering forest edges. Notably, these areas of high degradation coincided closely with the same locations classified as having very-low habitat quality, underscoring a consistent spatial pattern linking urban and infrastructure expansion to ecological deterioration.

Conclusions: The coupled CA-Markov and InVEST Habitat Quality modeling framework effectively demonstrates the land-use dynamics of Phitsanulok Province, showing that these changes are driven primarily by transportation systems and continued urban expansion, both of which exert a direct and inverse effect on ecosystem quality. Although the province's extensive forest cover helps to moderate the overall provincial-level rate of decline in habitat quality, urban fringes, major roads, and the transition zones between urban areas and forest land remain at considerable long-term risk of habitat fragmentation. The knowledge generated through this study can serve as a foundation for supporting urban planning efforts, the delineation of ecological buffer zones, and the management of urban expansion, all of which are necessary to achieve a sustainable balance between continued economic development and the conservation of biodiversity in the province.

On the Diophantine Equation p^x+(p+7)^y=z^2

Suton Tadee — Wed, 02 Sep 2026 00:00:00 +0700

Background and Objectives: One interesting part of number theory is Diophantine analysis, which is the study of integer solutions to equations. Diophantine analysis investigates to answer whether a certain Diophantine equation is unsolvable, or solvable with the unique integer solution, finitely many integer solutions or infinitely many integer solutions. The Diophantine equations come in many forms. One form that has received attention is the exponential Diophantine equation of the form , where are fixed positive integers and are non-negative integer variables. To find the non-negative integer solutions of the Diophantine equation, the Catalan’s conjecture plays an important role. This Conjecture stated that is the unique non-negative integer solution of the Diophantine equation , when and are non-negative integers such that , which remained unproven for over 150 years until it was proved by Mihăilescu in 2004. Over the past decade, the Diophantine equation of the form , where is a fixed positive integer, is a prime and are non-negative integers, has received considerable attention of many mathematicians in the study and search for solutions. In this paper, we solve the Diophantine equation for the case , which has never been studied before.

Methodology: The research and solutions presented here utilize mathematical proofs and fundamental concepts of number theory, such as prime numbers, congruences, and Legendre symbol. Here, some properties of prime number are applied to prove the theorems, such as: Let be a prime number with . If the Diophantine equation has a non-negative integer solution and is even, then . This will be useful to prove our main results. For the congruent method and Legendre symbol, we often use them in proofs to find contradictions.

Main Results: In this article, by using elementary methods, the Diophantine equation , where is a prime number and are non-negative integers, is investigated. The research results found that if , then the Diophantine equation has exactly two non-negative integer solutions. The solutions are and . Unfortunately, we are not yet able to find all non-negative integer solutions of the Diophantine equation for the case , but we can show the explicit non-negative integer solutions of the Diophantine equation under the given conditions. If and , then the Diophantine equation has the unique non-negative integer solution. The solution is . For the case , we prove that the Diophantine equation has a unique non-negative integer solution, . For the case , we prove that the Diophantine equation has the unique non-negative integer solution, which is . For the case , if the Diophantine equation has a non-negative integer solution , then there exists a non-negative integer such that and . Moreover, we present some conditions for non-existence of the non-negative integer solutions to the Diophantine equation, namely, (1) if , then the Diophantine equation has no non-negative integer solution. (2) if and there exists a positive integer such that is not power of and , then the Diophantine equation has also no non-negative integer solution.

Conclusions: By using elementary properties of prime numbers, congruences, and Legendre symbol, we present explicit non-negative integer solutions of the Diophantine equation for some prime number . Note that doesn’t necessarily have to be a prime number. Moreover, we show some conditions of non-existence of non-negative integer solutions to the Diophantine equation. In order to prove our main results, Mihăilescu’s theorem was also applied. This method can be applied to find non-negative integer solutions to similar Diophantine equations. Furthermore, it was found that there are some cases that remain unanswered, such as: case , which is an interesting open problem for further study and research.

Frequency Analysis for the Estimation of Annual Maximum Three-Hourly Rainfall at Don Mueang International Airport

Nipathorn Kitpanichayakul — Wed, 09 Sep 2026 00:00:00 +0700

Background and Objectives: Flood events occurring throughout numerous regions of Thailand have engendered considerable detriment to human life, private property, and the broader national economy. Regions of pronounced economic importance, most notably airport facilities, have been rendered incapable of sustaining normal operations, thereby precipitating flight delays and, in the most severe instances, the cancellation of scheduled services. The Aeronautical Meteorological Division of the Thai Meteorological Department, functioning as a governmental entity, is principally charged with the observation and reporting of meteorological conditions at aerodromes, the provision of aviation weather forecasts, and the issuance of advisories pertaining to meteorological phenomena deemed hazardous to aviation, in conformity with the regulatory frameworks promulgated by the World Meteorological Organization (WMO) and the International Civil Aviation Organization (ICAO). These functions collectively serve to support the provision of Air Navigation Services, with the overarching objective of ensuring operational safety and maximal efficiency. Notwithstanding the foregoing, the prevailing operational framework remains deficient in informational resources requisite for the effective management of water at airport facilities. In light of the aforementioned considerations, substantive scholarly interest has emerged regarding the estimation of maximum rainfall magnitudes, with particular emphasis on airport environs, with a view to elucidating the characteristics of maximum rainfall occurrence and to identifying an appropriate analytical model for its estimation. The findings of such an investigation are anticipated to furnish supporting information to stakeholders within the aviation industry and to meteorologists engaged in the practice of aeronautical meteorology and are further intended to inform prospective developments in the provision of aeronautical meteorological information services under the purview of the Aeronautical Meteorological Division, Thai Meteorological Department.

Methodology: Three-hourly rainfall data were collected from January 1981 to December 2024. The collected rainfall data were compiled and organized into a hydrological dataset. For each year of record, only the single highest three-hourly rainfall value was retained, in accordance with the recorded observation times, in order to construct an Annual Maximum Series. As a result, the Annual Maximum Three-Hourly Rainfall series for Don Mueang International Airport over the period January 1981 to December 2024 consists of exactly one value per year, yielding a total of 44 data points corresponding to the 44-year period of record. Subsequently, the probability of exceedance and the associated return period were determined, together with the frequency factors corresponding to each candidate probability distribution considered in the frequency analysis. The rainfall values estimated from each distribution were then computed, and the goodness-of-fit of each distribution was evaluated by means of the Chi-square test at a significance level of α= 0.05, in order to identify the probability distribution that most appropriately represents the observed rainfall data. In the final step, a regression equation relating the rainfall values estimated from the best-fit probability distribution to their corresponding return periods was derived. This equation provides the basis for estimating the Annual Maximum Three-Hourly Rainfall of Don Mueang International Airport at a specified return period.

Main Results: The occurrence of the Annual Maximum Three-Hourly Rainfall, when classified by month, showed that such rainfall occurred from March to December, occurring most frequently in September. When classified by observation time, the rainfall occurred at observation times ranging from 0700 hours (cumulative rainfall recorded from 04:00 to 07:00) through 0400 hours (cumulative rainfall recorded from 01:00 to 04:00), occurring most prominently at the 1900-hour observation time (cumulative rainfall from 16:00 to 19:00) and the 2200-hour observation time (cumulative rainfall from 19:00 to 22:00). When classified by day-of-month period, the rainfall occurred most frequently during days 21–31 of the month, followed by days 11–20 of the month. When the goodness -of-fit test was conducted using the Chi-square test at a significance level of 0.05, the Log-Pearson Type-III Distribution was found to be the most appropriate probability distribution for estimating the Annual Maximum Three-Hourly Rainfall at Don Mueang International Airport (p > 0.05). The regression equation for estimating the rainfall value at a given return period is: where denotes the estimated Annual Maximum Three-Hourly Rainfall (mm), and represents the return period (years). The estimated rainfall values were 54.51 mm at a return period of 1.02 years, 99.98 mm at a return period of 10 years, and 145.85 mm at a return period of 100 years.

Conclusions: The occurrence of the Annual Maximum Three-Hourly Rainfall was found to span from March to December, occurring most prominently in September. When classified by observation time, the rainfall occurred most prominently at the 1900-hour and 2200-hour observation times. When classified by day-of-month period, the rainfall occurred most prominently during days 21–31 of the month, followed by days 11–20 of the month. The probability distribution most appropriate for estimating the rainfall of Don Mueang International Airport.

Ecological Assessment of Aquatic Life Shelters under Community-Based Management in Songkhla Lagoon

Preeyalak Konongbua, Wijittra Amornwiriyachai, Tueanta Ramarn — Wed, 09 Sep 2026 00:00:00 +0700

Background and Objectives: Songkhla Lagoon is the only lagoon ecosystem in Thailand. The lagoon supports high biodiversity and serves as an important natural resource for surrounding coastal communities, particularly in fisheries, aquaculture, and local cultural livelihoods. However, long-term resource exploitation and environmental changes have resulted in declines in fish abundance and ecosystem productivity. In response to these problems, local fishing communities have developed various conservation activities, particularly the construction of Aquatic Life Shelter (ALS), locally known as “Ban Pla”, to enhance ecosystem productivity. Despite their widespread use, systematic ecological assessments and empirical evidence regarding their effectiveness remain limited. Therefore, this study aimed to investigate the structural types and evaluate the ecological outcomes of ALS in communities surrounding Songkhla Lagoon, with particular emphasis on designs adapted to local ecological conditions and community-based management processes.

Methodology: The study was conducted in eight fishing communities located across the upper, middle, and lower zones of Songkhla Lagoon. Aquatic Life Shelter types and baseline environmental characteristics, including water depth, bottom substrate, wave and current conditions, locally available materials, and biological conditions, were surveyed in collaboration with local fishers and community leaders. This information was used for site selection and the development of ALS designs appropriate to the ecological context of each area. Ecological assessment was subsequently conducted at five sites by comparing fish diversity and biomass before and six months after ALS installation. Local fishing gears appropriate to each site were used, with three replicates per site. Fish species and biomass were recorded, and fish diversity was evaluated using the Shannon–Wiener diversity index (H′). Differences in diversity before and after ALS installation were analyzed using a paired t-test at a significance level of p < 0.05.

Main Results: Five major types of ALS were identified in Songkhla Lagoon, including cage-type, concrete-based cluster, linear branch arrangement, aquatic life shelter, and traditional branch pile models. Each design differed according to local ecological conditions such as water depth, wave exposure, current conditions and available local materials. Ecological assessment revealed that the average Shannon–Wiener diversity index increased from 0.19 to 1.16 within six months after ALS installation, indicating changes in fish community structure and increased fish diversity in the study areas. Fish species richness increased at all five assessment sites: from 1 to 14 species at Ban Chai Khlong, 2 to 17 species at Ban Pak Pra, 1 to 5 species at Ban Lam Kula, 2 to 4 species at Ban Klang, and 1 to 4 species at Ban Mai. A total of 26 aquatic species, comprising 25 fish species and one shrimp species, were recorded during the study period. Fish biomass also showed an increasing trend across the study sites. For example, mean fish biomass at Ban Chai Khlong increased from 21.27 ± 0.67 to 46.33 ± 0.87 kg, while that at Ban Pak Pra increased from 2.45 ± 0.32 to 8.60 ± 0.65 kg. The reappearance of indigenous fish species and several less frequently encountered species, as reported by local fishers, including Batrachocephalus mino, Megalops cyprinoides, Barbonymus schwanenfeldii, and Osteochilus melanopleurus, was also observed following ALS installation. The findings demonstrated a relationship between ALS installation and increased fish diversity in the study areas. The ALS designs reflected adaptation to site-specific ecological conditions. Cage-type ALS were suited to shallow-to-moderately deep waters with low wave exposure, whereas concrete-based cluster ALS were used in deeper waters with stronger currents. The Mangrove-Integrated Aquatic Life Shelter integrates ALS structures with mangrove planting to increase habitat complexity.

Conclusions: The construction of ALS in Songkhla Lagoon was associated with increased fish diversity and the reappearance of indigenous fish species in the study areas. The findings suggest that ALS may contribute to habitat restoration in brackish coastal ecosystems. Rather than functioning solely as structures for aggregating fish, appropriately designed ALS have the potential to serve as habitat restoration tools, particularly when their designs are adapted to local ecological conditions and implemented through community participation. Selection of an appropriate ALS design should therefore consider physical environmental conditions, locally available materials, local ecological knowledge, and patterns of community resource use.

Mangrove Red Snapper (𝙇𝙪𝙩𝙟𝙖𝙣𝙪𝙨 𝙖𝙧𝙜𝙚𝙣𝙩𝙞𝙢𝙖𝙘𝙪𝙡𝙖𝙩𝙪𝙨) Culture Systems and Demand for Stocking Fish in Southern Coastal Thailand

Surinporn Sri-in, Vutthichai Oniam, Wasana Arkronrat , Panitan Kaewjantawee — Thu, 10 Sep 2026 00:00:00 +0700

Background and Objectives: Mangrove red snapper (Lutjanus argentimaculatus) is a high-value marine fish with potential for coastal aquaculture, yet evidence linking actual culture systems to farmers’ requirements for stocking-fish size, quality, quantity, and delivery timing remains limited. This study examined culture systems, estimated farm-level demand for stocking fish, and analyzed the factors and constraints affecting adoption decisions across four southern coastal provinces of Thailand. National statistics do not report aquaculture production of this species separately, while marine-capture data for the broad red-snapper category do not distinguish L. argentimaculatus. Such statistics therefore cannot directly represent farm demand. The findings were intended to support stocking-fish production and distribution aligned with actual farm calendars, not to estimate aggregate provincial, regional, or national demand.

Methodology: This descriptive cross-sectional study used a convergent mixed-methods design. Data were collected from September 2024 to May 2025 from 80 purposively selected informants: 40 mangrove red snapper farmers in Ranong and Phang Nga and 40 coastal aquaculture farmers not currently culturing the species in Ranong, Phang Nga, Chumphon, and Prachuap Khiri Khan. Two structured interview schedules and a field-observation form were used. Quantitative data were analyzed using frequencies, and percentages; qualitative data were analyzed by content analysis and integrated with the quantitative findings. Sites and informants were purposively selected as information-rich cases with direct experience relevant to the research questions. The instruments covered farm and cage characteristics, fish sources and prices, transport, stocking density, grading, grow-out duration, feed, cycles, preferred sizes and quantities, decision factors, and constraints. Three experts assessed item–objective congruence, which ranged from 0.67 to 1.00. The researchers conducted face-to-face interviews, observed farms, and prepared field notes. Interview and observation evidence was compared, and interpretations were checked against original records. Requirements were calculated for a simulated 10-cage farm operating one or two annual cycles, separately for each size class and without losses or replacement fish.

Main Results: All 40 mangrove red snapper farms used floating cages near communities at canal mouths, river mouths, or coastal sites and sourced 7.50–20.00 cm stocking fish from the wild, local fishers, collectors, and fisheries agencies. Among the 80 informants, 10.01–15.00 cm fish were most preferred (n = 37, 46.25%), followed by 7.50–10.00 cm (n = 30, 37.50%) and 15.01–20.00 cm fish (n = 13, 16.25%). Under a simulated 10-cage farm scenario with one or two production cycles annually, estimated demand was 540–1,440 fish per year. Purchasing decisions emphasized vigor, size uniformity, disease tolerance, price, and availability, while major constraints were irregular supply, size mismatch, and transport. Two cage dimensions were recorded: 3 × 3 × 2.5 m and 2.5 × 2.5 × 2 m. Prices for the three successive size classes were approximately THB 15–18, 20–30, and 30–40 per fish. Transport covered no more than 100 km and took 1–2 hours in aerated tanks. Reported stocking densities were 4.0, 3.5, and 3.0 fish/m3, and grow-out periods to at least 600 g were approximately 8–9, 7–8, and 6–7 months. Fresh fish was the principal feed. Stocking was concentrated in February–March and June–July. In the one-cycle scenario, requirements for the three sizes were 720, 630, and 540 fish; in the two-cycle scenario, they were 1,440, 1,260, and 1,080 fish, calculated separately. Each respondent selected one main factor: the first two categories together accounted for 52.50%, and the first four for 81.25%. Non-adopters’ considerations formed four themes—quality, price and service, readiness for culture, and trust and networks—while anticipated constraints were uneven size, transport injury, latent disease, and price fluctuations.

Conclusions: Stocking-fish supply systems should integrate production, size grading, health screening, transport, and delivery with farm production calendars through advance ordering and post-delivery monitoring. Because demand was derived from a farm-level simulation, the findings apply only to the study sites or farms with comparable conditions and should not be interpreted as provincial, regional, or national estimates. Advance orders should specify source, size, quantity, delivery date, and destination, supported by protocols for grading, health screening, acclimation, transport, and post-delivery monitoring. Although 10.01–15.00 cm was most frequently preferred, planning should jointly consider quality, availability, price, and service. Broader application requires inventories of active farms and cages, cage-system trials of survival, cost, and return, and longitudinal monitoring of water quality, fish health, and transport outcomes.

Probiotic Application in Dietary Supplements for 𝘼𝙥𝙞𝙨 𝙢𝙚𝙡𝙡𝙞𝙛𝙚𝙧𝙖

Boonmee Kavinseksan, Wanida Chuenchan, Somsak Yooboriboon — Tue, 01 Sep 2026 00:00:00 +0700

Background and Objectives: Currently, the honey bee (Apis mellifera) industry, including Thailand’s, is experiencing a critical decline known as Colony Collapse Disorder (CCD), which poses an immediate threat to global ecosystems and food security. The primary causes of this crisis stem from combined threats, including fluctuating climate change, pesticide contamination in the environment, and the outbreak of American Foulbrood (AFB) caused by Paenibacillus larvae. These factors result in stress for the bees and a loss of balance in the gut microbiota (gut dysbiosis), which weakens the natural immune system. Although the use of supplementary diets is a primary approach to sustain bee populations during periods of natural pollen scarcity, general supplements lack essential biological components. Therefore, this academic article aims to analyze and present guidelines for the use of probiotics mixed into supplementary diets as a biological innovation to mitigate the impacts of such crises and sustainably enhance the well-being of honey bees in Thailand.

Methodology: The study was conducted by collecting, analyzing, and synthesizing knowledge from experimental research reports and academic documents on the application of probiotics in honey bees. The focus was specifically on autochthonous probiotic strains in Thailand, such as Lactobacillus, Bacillus, and Priestia, which possess outstanding properties in enduring hot and humid climates. The study also covers management methods for supplementary diets, both in the form of mixing in pollen substitute and dissolving in sugar syrup for spray application. Furthermore, key biological indicators were evaluated, including survival rates, changes in body weight, and the quality of reproductive cells in drones, under the specific tropical environmental conditions of Thailand.

Key findings: Traditional supplementary diets lacking probiotics result in an imbalance of the core microbiota in the bee gut, causing bees to lose their biological barriers for disease prevention. However, when autochthonous probiotic strains are added to the supplements, it was found that these microorganisms effectively perform the functions of natural microbiota through the mechanism of competitive exclusion to compete for attachment space on the intestinal wall and produce antimicrobial substances in the bacteriocin group, as well as organic acids that inhibit P. larvae. In terms of physiology, bees receiving probiotic supplements showed an average weight increase of 10-15% and a longer average lifespan compared to the group receiving only supplementary diets. This is because probiotics assist in the digestion of complex nutrients and stimulate signaling through insulin-like peptides. Additionally, significant results were found in drones, where probiotics helped promote spermatogenesis, increasing the concentration and strength of sperm, which is an important factor for reproductive success. At the molecular level, probiotics also help stimulate the expression of immune genes to secrete antimicrobial peptides (AMPs), such as apidaecin and defensin, to protect against environmental threats.

Implications: The development of bee supplements mixed with autochthonous probiotics is a high-potential strategy for addressing the shortage of natural food plants, as local microorganisms adapt well to hot and humid climates. This approach helps beekeepers reduce costs from the loss of bee populations during the off-season of floral blooms and helps elevate honey standards to be antibiotic-free, aligning with export requirements. Furthermore, it serves as a model for producing high-quality supplementary diets that mimic the characteristics of natural food to maintain the strength of the beehive in performing pollination for economic crops and preserving the balance of the ecosystem.

Conclusions: The application of probiotics in supplementary diets for honey bees is an innovation that closes the gap between supplements and natural food. These microorganisms not only function as immunostimulants and pathogen inhibitors but also help improve the metabolism and reproductive systems of bees to a level of integrity comparable to receiving natural food, resulting in healthier beehives that can effectively resist diseases and fluctuating environmental conditions.