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Objectives: In this study, a new brisk, efficient and precise method of first derivative UV spectrophotometric was developed and validated for the estimation of eugenol and scopoletin simultaneously from the in-house Avipattikar churna. Materials and Methods: The method involved estimation of eugenol and scopoletin by simultaneous equation of first derivative spectra at 296 nm and 278.66 nm respectively in 0.1 N HCl. As per the Beer-Lambert law, proportional absorbance (linearity) was recorded in the concentration limit of 20-100μg/mL for both eugenol and scopoletin. Results: The method validation was done in reference to ICH (International council for harmonisation of technical requirements for pharmaceuticals for human use) norms comprising of accuracy, linearity, precision, the limit of detection, and quantification of standard from churna. This method was found to be precise as % relative standard deviation was less than 2%. The mean recoveries of triplicate samples were found in the range of 98.52 - 101.30% and 100.51 - 100.56 % for eugenol and scopoletin respectively. The limit of detection and limit of quantification were found to be 2.62μg/mL and 7.96μg/mL for eugenol respectively. The limit of detection and limit of quantification were found to be 1.54μg/mL 4.66μg/mL for scopoletin respectively. Conclusion: The developed estimation method was found to be specific, rapid, precise, and accurate for the analysis of eugenol and scopoletin in the Ayurvedic churna and in formulation without showing any interference. [ABSTRACT FROM AUTHOR]

Possessing mathematical competence is a pre requisite for independently comprehending, understanding and applying all features of mathematical modelling in a particular setting. This research study thus explores the mathematical modelling competencies that Grade 10 learners exhibit while solving contextual problems in a mathematics learning and teaching context, with specific reference to using mathematical modelling. Since mathematical modelling is a fairly new teaching strategy used in mathematics teaching some teachers may be ignorant of the skills and competencies required for learners to solve problems efficiently. A mixed-methods approach to this study was decided upon and a case study design used within an interpretative paradigm in an effort to ascertain the levels of mathematical modelling competencies of a non-random sample of 20 Grade 10 learners. Participant learners who attended a Western Cape school were requested to solve a set of word problems involving the use of simultaneous equations. Task based activities and observations were used as a means to collect data, as well as semi-structured interviews to gauge participating learners' views and experiences. Qualitative content analysis methods were employed together with basic descriptive statistical methods. [ABSTRACT FROM AUTHOR]

With the help of microcredit, a farmer's way of life could be transformed from one of utter destitution to one of greater dignity. For the poor and disadvantaged, especially rural farmers, it unlocks potential and increases productivity and well-being. This study investigated the determinants of demand and supply of microcredit among fish farmers in Osun State. A multi-stage sampling procedure was used to select 150 fish farmers and 50 microcredit providers for the study. Data were analyzed using descriptive statistics and a simultaneous equation model. The result revealed that many fish farmers are males (86.5%), married (77%), and educated (95%). Simultaneous equation estimates revealed that farmers' income, age, interest rate, and educational level determine microcredit demand among fish farmers whereas liquidity, experience in lending, and interest rate determine the microcredit supply in the study area. The findings of the study revealed that microcredit suppliers consider several factors before supplying credit to fish farmers. [ABSTRACT FROM AUTHOR]

In the 21st century, teaching and learning mathematics courses witness significant expansion and development of technology use, which creates a shift from teacher-centred to student-centred learning engagement. Student engagement (SE) faces many challenges of poor performance and student difficulty in solving simultaneous equations involving indices (SEII), among others. This paper presents an evaluation viewpoint of the learning strategy (LS) with cooperative learning strategy (CLS) and GeoGebra (GG) integration to support SE in SEII. The LS employs the think-pair-share approach and the six (6) principles of learning phases associated with constructivism ideology. The discussion of the preliminary mathematical achievement test (MAT-test) from pre-and post-tests with 41 students who have learned SEII using the developed LS is also presented. Semi-structured interviews were conducted with three experienced lecturers to provide feedback and recommendations on interacting with LS. The themes that emerge from those lecturers include the connection between LS phases, specific material, cooperative activity, playfulness in the discovery process, and thinking. Experts' feedback on the LS's content reasoning and content learning strategy through a questionnaire was tested using Fleiss multi-rater Kappa and showed good inter-rater reliability and agreement between them. The estimated marginal means covariate of the ANCOVA test was then examined, and the results supported the necessity for a learning strategy to be developed. The findings revealed that the LS, with CLS and GG integration, has the potential to be educationally effective in enhancing SE in SEII. [ABSTRACT FROM AUTHOR]

This paper examines the bidirectional relationship between sustainability and outreach of microfinance institutions (MFIs) in the MENA region, using unbalanced panel data regression during the period from 1999 to 2018. The simultaneous equation model (SEM) is used based on the 2SLS regression considering endogeneity problem between sustainability and outreach. Two main systems are developed based on SEM; the first relates sustainability with breadth of outreach, while the second includes sustainability and depth of outreach. Results state that sustainability and outreach are complementary objectives, and the direction of their relationship is from outreach to sustainability. This finding is tested and supported using various robustness checks, namely: excluding firms with few data, using other methods to estimate 2SLS regression model, and examining the impact of sustainability on outreach based on their indices developed based on the TOPSIS method. The study concludes with some suggestions for future research in this field. [ABSTRACT FROM AUTHOR]

Purpose: The literature argues that human activities are responsible for environmental pollution and world climate change. Africa is the second-largest continent by population and its socio-economic conditions are adversely affected by climate change due to environmental pollution. Therefore, this study investigates the relationship between human activities, the environment and the economic growth of 38 African countries from 2000 to 2018. Design/methodology/approach: This study employs a simultaneous equations model called Seemingly unrelated regression. Findings: Human capital development (HDI) and environmental health (EH) have a positive and non-linear relationship, while HDI and ecosystem vitality (EV) are negative and non-linear. The relationship between gross domestic product per capita (GDPPC) and EH is negative and non-linear. However, the GDPPC-EV link is insignificant. Trade openness (TO) and EV have a negative and non-linear relationship, but trade significantly improves EH. Urbanisation-EV relationship is positive and non-linear. However, urbanisation significantly reduces EH. Technology has a positive and non-linear relationship with EH and EV. The study also found that EH and EV positively affects the economy. Originality/value: This is the first study to analyse the most concerned countries in-depth. Thus, it provides appropriate and sound policies that consider the unique characteristics of the nations. Moreover, it uses a robust estimation technique that overcomes the endogeneity problem and offers insight into the relationship between the variables, including the feedback effect of the environment on growth. [ABSTRACT FROM AUTHOR]

In this paper, the Wiener-Hopf technique is used to analyze the plane wave diffraction rigorously by a semi-infinite parallel-plate waveguide with five-layer material loading for E polarization. Introducing the Fourier transform of the unknown scattered field and applying boundary conditions in the transform domain, the problem is formulated in terms of the simultaneous Wiener-Hopf equations satisfied by unknown spectral functions. The Wiener-Hopf equations are solved exactly via the factorization and decomposition procedures leading to exact and approximate solutions. Taking the Fourier inverse of the solution in the transform domain, the scattered field in the real space is explicitly derived. For the region inside the waveguide, the scattered field is expressed in terms of the waveguide TE modes, whereas the field outside the waveguide is evaluated asymptotically with the aid of the saddle point method leading to a far field expression. Numerical examples of the radar cross section (RCS) are presented for various physical parameters and far field scattering characteristics of the waveguide are discussed in detail. [ABSTRACT FROM AUTHOR]

This paper presents an application of cavity modeling technique to study its effectiveness in analyzing a complex waveguide network that requires large number of cavities and waveguides for its modeling, has apertures both on transverse and longitudinal planes as well as that supports more than one propagating modes. A five-port four-hole dual-side backward coupler has been considered for this purpose. The proposed structure has been modelled using four waveguide sections, including a square waveguide, and forty-four cavities. The modeling resulted fifty-three interfacing apertures, which required total one hundred six simultaneous matrix equations to be solved. The matrix equations have been solved using Galerkin's specialization of method of moments to find the frequency response of the network. It has been demonstrated that the cavity modeling technique can be applied to analyze such complex rectangular waveguide based networks. The analysis has been verified by comparing numerically calculated data with literature available data. [ABSTRACT FROM AUTHOR]

Technology has been proven useful to support and transform teaching and learning. It is helping students to understand, perform, learn and explore calculations in mathematics to enhance students' understanding, knowledge and visualization. Simultaneous equations are very are important in computations for analysis or to find solutions quickly of these equations, thus, increases the understanding in the subject. The 21st century has added a number of enhancements and impediments to teachers and students. The hyperconnected digital environment requires manifold decisions on the part of educational stakeholders. This quasi-experimental study with non-equivalent control group post-test only design was administered to explore the effect of free software called 'Symbolab Calculator' in teaching simultaneous equations on students' conceptual understanding at the elementary level in Pakistan. A total of 66 students of a private school participated in the present study. They were assigned into experiment and control groups. One group was taught simultaneous equations with Symbolab Calculator whereas the other group underwent learning with conventional way. Participants' mathematics achievement was measured using post-test at the end of intervention. Independent sample t-test was based on the syllabus of Oxford Cambridge Mathematics book. The findings of the study clearly revealed that the use of the Symbolab for teaching simultaneous equations was more effective as compared to a traditional method of teaching. Hence, the test scores showed that there was a significant difference in mathematics achievement. The results of the present study are expected to benefit schools, colleges, universities and teachers that are looking for the innovation in math education. [ABSTRACT FROM AUTHOR]

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Recently, Chappelon and Ramírez Alfonsín defined the square Frobenius number of coprime numbers m and n to be the largest perfect square that cannot be expressed in the form mx + ny for nonnegative integers x and y. When m and n differ by 1 or 2, they found simple expressions for the square Frobenius number if neither m nor n is a perfect square. If either m or n is a perfect square, they formulated some interesting conjectures which have an unexpected close connection with a known recursive sequence, related to the denominators of Farey fraction approximations to √ 2. In this note, we prove these conjectures. Our methods involve solving Pell equations x² - 2y² = 1 and x² - 2y² = -1. Finally, to complete our proofs of these conjectures, we eliminate several cases using several results related to solutions of simultaneous Pell equations. [ABSTRACT FROM AUTHOR]

Airborne LiDAR has been extensively used for estimating and mapping forest attributes at various scales. However, most models have been developed separately and independently without considering the intrinsic mathematical relationships and correlations among the estimates, which results in the mathematical and biophysical incompatibility of the estimates. In this paper, using the measurement error model approach, the error-in-variable simultaneous equation (SEq) for airborne LiDAR-assisted estimations of four forest attributes (stand volume, V; basal area, G; mean stand height, H; and diameter at breast height, D) for four forest types (Chinese fir, pine, eucalyptus, and broad-leaved forest) is developed and compared to the independence models (IMs). The results indicated that both the SEqs and IMs performed well, and the rRMSEs of the SEqs were slightly larger than those of the IMs, while the increases in rRMSE were less than 2% for the SEqs. There were statistically significant differences (α = 0.05) in the means of the estimates between SEqs and IMs, even though their average differences were less than ±1.0% for most attributes. There were no statistically significant differences in the mean estimates between SEqs, except for the estimates of the D and G of the eucalyptus forest. The SEqs with H and G as the endogenous variables (EVs) to estimate V performed slightly better than other SEqs in the fir, pine, and broad-leaved forests. The SEq that used D, H, and V as the EVs for estimating G was best in the eucalyptus forests. The SEq ensures the definite mathematical relationship among the estimates of forest attributes is maintained, which is consistent with forest measurement principles and therefore facilitates forest resource management applications, which is an issue that needs to be addressed for airborne LIDAR forest parameter estimation. [ABSTRACT FROM AUTHOR]

Forest biological disaster control (FBDC) is appealing the attention in China and even across the world, while the control system plays a pivotal role in the entire control work. The survey-based comprehensive indicators system was developed to evaluate the perceived effectiveness of the entropy weight model and the perceived responsibilities of the FBDC system of China from the perspective of government administrators at the province-, prefecture-, and county- levels. Ordinary Least Square (OLS) and Simultaneous Equations Models (SEM) were further developed to quantitatively analyze the affecting factors of the perceived effectiveness. The results indicated that the perceived effectiveness of the FBDC system in China was relatively low, with a value of 47.18 (the range is 0–100). In specific, the county level has the highest value of 48.85, while the province level has the lowest value of 42.99. The major limiting factors perceived are the insufficiency of the funds and employees. In addition, the intelligentization level, the implementation of the quarantine enforcement, the infrastructure construction, and the involvement of the local communities also need to be further improved. The salary does not positively affect the perceived effectiveness, while administrators with higher education levels and ages usually have higher salaries. Furthermore, compared with the province- and prefecture-level agencies, the county-level agencies have higher perceived effectiveness and more perceived responsibilities with higher workloads. Thus, future policies are suggested to focus on diversifying the investment sources, refining the employee recruitment and promotion system, and paying more attention to the county-level agencies. The results of this study could help to enhance the understanding of the FBDC system of China, hence improving the control efficiency and reducing the economic loss caused by forest biological disasters in China. [ABSTRACT FROM AUTHOR]

The effect of each trading rule is not completely independent. From the perspective of market differentiation, we establish the linear simultaneous equation model to study the comprehensive influence of the price limit rule and the day trading rule on the quality of China's stock market and investigate whether it is a synergistic or an anti-synergistic effect. To eliminate the influence of other factors before or after the reform of the trading rules, we establish the difference-in-difference simultaneous equation model for further testing. Results show that when the stock market is divided into the Shanghai A-share market, the Shanghai B-share market, the Shenzhen A-share market, and the Shenzhen B-share market, the simultaneous implementation of the price limit rule and T + 1 trading rule significantly reduces the liquidity and market efficiency of the stock market, significantly increases the volatility of markets, and does harm to the market quality. The interaction effect further aggravates the adverse impact of a single trading rule on the liquidity and market efficiency of the stock market, and weakens the beneficial impact of implementing a single trading rule to stabilize the market. The interaction effect has an anti-synergistic effect, and the results are robust. [ABSTRACT FROM AUTHOR]

Development zones constitute a special type of place‐based policy that has been implemented worldwide. As an essential economic development engine, Chinese National Economic and Technological Development Zones (NETDZs) are perceived as a successful example. However, few studies have looked into the channel effects at work in development zones concerning industrialization and urbanization, despite the crucial nature of such effects with regard to sustainable development of development zones. Following a brief description of NETDZs and their theoretical mechanisms with urban economic performance, industrialization, and urbanization, this study used a simultaneous equation model to generate empirical evidence of the impact of the establishment of NETDZs on urban economic performance and its channel effects through industrialization and urbanization. The results confirm that NETDZs exerts a positive and significant impact on urban economic performance, and NETDZs also show indirect influence in urban growth through urbanization. Although significant and positive intermediation of industrialization remains invalid, foreign direct investment and investment in fixed assets are still crucial in Chinese industrialization. Both industrialization and urbanization play an important role in Chinese urban economic development. Meanwhile, compared with eastern regions more influenced by urbanization, industrialization still acts as a major impetus in inland China. [ABSTRACT FROM AUTHOR]

In this paper, we present a detailed study of both nonrotating and rotating black hole solutions in f (R) = R − 2 α R model. The complicated expression of Ricci scalar, which appears in the vacuum field equations, brings the main difficulty of searching analytic solutions. In the case of searching nonrotating black hole solution, we use the 00 component minus 11 component of field equations to constrain the Ricci scalar. In order to obtain analytic solutions of rotating black hole, two strategies are used. One is the simplification of the line element using Carter's consideration that the Klein–Gordon equation is separable. The other is that we give the general solutions of the simultaneous equations of 00 minus 11 component equation and 01 component of the field equations. These strategies greatly simplify the process and difficulty of solving the axisymmetric solutions. The calculation process is more friendly to generalize to other modified gravities. [ABSTRACT FROM AUTHOR]

This paper evaluates the deposit and purchase pricing of purchase contracts in a risk-neutral framework. First, we determine the fair deposit price of a single-installment purchase contract based on theoretical modeling and numerical analysis. Second, the buyer's threshold pricing in dual-installment and multi-installment contracts is investigated under the framework of compound options. Lastly, the pricing behavior of deposits and purchases is further analyzed using a simultaneous equations modeling framework. [ABSTRACT FROM AUTHOR]

This paper examines the impact of chronic illnesses on labor force participation using labor market surveys data for Egypt and Tunisia. The study also investigates the reverse effect of labor force participation on the incidence of chronic diseases. We adopted the simultaneous equations modeling technique to address the potential endogeneity of chronic illnesses in the labor participation equation. The results reveal that chronically ill people are less likely to participate in the labor force in both Egypt and Tunisia. However, the sub-samples analysis indicates some variations across gender and age groups. Specifically, the effect of chronic illnesses is found to be larger and significant for the male group compared to female counterparts. Likewise, the feedback effect shows that labor force participation exerts negative impact on chronic illness, particularly for the total sample. Moreover, the impact of labor force participation on chronic diseases in elder group is larger compared to its effect in the younger group. The study recommends that policymakers in the Arab countries should endeavor to reduce chronic health conditions in order to boost labor force participation and productivity. [ABSTRACT FROM AUTHOR]

The non-causal ("forward-looking") solution used routinely in academic macroeconomics may represent a violation of a law of entropy, namely that the direction of time is one way (from the past and towards the present), and that the variance of economic processes increases with time. In order to re-establish a degree of compatibility with the law of entropy, so called hybrid forms are required add-ins to DSGE (Dynamic Stochastic General Equilibrium) models. However, the solution that uses hybrid forms is a particular special case of a causal solutions of autoregressive distributed lags, VARs and recursive and simultaneous equations models well known from empirical macro econometrics. Hence, hybrid forms of small scale DSGE models can be analysed and tested against competing model equations, using an econometric encompassing framework. [ABSTRACT FROM AUTHOR]

Little is known about the trade-off mechanism underlying raising bank capital and enhancing bank liquidity creation, as empirical evidence is sparse. Pursuing Basel II target capital seems challenging and costly because it could generate unintended consequences, such as reducing liquidity creation. Thus, the aim of this study is to point out that the pursuit of raising capital to meet Basel II standards in recent years has limited the liquidity creation function of banks. This finding is reliable and consistent across different research methods, i.e. least absolute shrinkage and selection operator (LASSO regression) and the simultaneous equations model (SEM). We chose Vietnam's banking system for this study because applying Basel II in Vietnam has been topical in recent years and also more challenging than in the rest of the world. Our finding strengthens academically the financial fragilitycrowding out hypothesis developed by Diamond & Rajan (2000). [ABSTRACT FROM AUTHOR]

The effects of temperature have largely been under-examined in climate change studies. This study examines both direct and indirect effects of temperature on environmental degradation using the sample of 103 middle-income countries from 1985 to 2019. Unlike previous studies in which a single equation approach is utilized, our study considers the simultaneous equations modelling to examine the energy-growth-environment nexus incorporating temperature and corruption. The difference and system generalized method of moments estimations for panel data are used. Empirical results from this paper confirm both the direct and indirect effects (via energy consumption) of temperature on environmental degradation. We find corruption harms economic growth in middle-income countries. The continued use of fossil fuel energy in energy consumption deteriorates environmental quality. Our findings confirm the critical role of the services sector in supporting economic growth and reducing emerging consumption, leading to increased environmental quality. Findings from our study reconfirm the vital role of renewable energy and its extended use in achieving dual objectives of supporting economic growth and improving the environmental quality in middle-income countries. [ABSTRACT FROM AUTHOR]

Forecasting stock price movement direction (SPMD) is an essential issue for short-term investors and a hot topic for researchers. It is a real challenge concerning the efficient market hypothesis that historical data would not be helpful in forecasting because it is already reflected in prices. Some commonly-used classical methods are based on statistics and econometric models. However, forecasting becomes more complicated when the variables in the model are all nonstationary, and the relationships between the variables are sometimes very weak or simultaneous. The continuous development of powerful algorithms features in machine learning and artificial intelligence has opened a promising new direction. This study compares the predictive ability of three forecasting models, including support vector machine (SVM), artificial neural networks (ANN), and logistic regression. The data used is those of the stocks in the VN30 basket with a holding period of one day. With the rolling window method, this study got a highly predictive SVM with an average accuracy of 92.48%. [ABSTRACT FROM AUTHOR]

Large-scale air pollution has an impact on the health and travel of residents in China. First, this article uses the gravity model and finds that China's air quality presents a typical spatial correlation network. The network structure has changed from complex to simple, indicating that China's air quality is gradually improving. Second, this paper uses spatial simultaneous equations to study the effect of air quality on residents' health. The results show that an increase in the air quality index of local and surrounding provinces will have a significant impact on the health of residents. The absolute and relative air quality affects the lives of residents. The decline in the health of residents from the previous period will prompt the government to adopt various pollution reduction policies, which will improve air quality in the current period. Based on the empirical research conclusions, this article makes policy recommendations. [ABSTRACT FROM AUTHOR]

The supply and demand of various fresh chili types correspond to one another simultaneously because they can be complementary or substitute products. This study aimed to simultaneously examine the supply and demand model of red chili and cayenne peppers to support innovative chili enterprise system development. The methodology is the simultaneous equation system panel data using the years 2010–2020 time-series and provincial cross-sectional data combined with data mining techniques. The two-stage least square method was used for the estimation and simulation of the models. The results of the models comprise three identities and ten structural equations. The resulting models are all statistically fit with some drawbacks owing to the micro-level data availabilities. The simulations on the labor wages, prices, demand, and production for red chili and cayenne peppers affected the other variables within the model. In conclusion, the chili supply and demand models could support the development of the innovative chili enterprise system; however, this requires proactive collaboration and participation from all the relevant institutions and actors. Moreover, this research model is potentially applicable to other horticultural commodities. [ABSTRACT FROM AUTHOR]

We estimate foreign direct investment elasticities of output, of unskilled and skilled labor, and of unskilled and skilled wages for Chile, both at an aggregate level and for eight economic sectors. We use regional data from official Chilean sources ranging from 2012 to 2019 and data from economic sectors in each region for the period 1996–2011. Estimates are based on a simultaneous equation approach, which considers the two-way relationships between FDI and output as well as the relationships between output, labor, and wages stressed by the duality theory of production in economics. The estimations confirm that FDI triggers growth and that FDI follows growth. Due to the positive effects on output, FDI boosts employment creation, particularly of skilled labor. The estimated effects on wages are not significant, either statistically or practically. The output and labor effects of FDI are positive and significant in all economic sectors, but point estimates suggest that they could be larger for the agriculture-forestry-fishing sector. The results indicate that realistic increases in FDI can have substantial output and employment effects in Chile. [ABSTRACT FROM AUTHOR]

As an important part of e-commerce, online reviews play a significant role in consumers' purchase decisions. This study investigated the dynamic effects of electronic word of mouth (eWOM) and the number of people wishing to watch a movie on movie sales and supplies in the Chinese movie market. Using a dynamic simultaneous equation system and data of 76 films, this study analyzed the interrelationships between eWOM and movie sales and supplies. Our findings showed that both the volume and valence of eWOM affected movie sales and supplies significantly. The number of people who wanted to watch a movie had an opposite effect on movie sales and supply; eWOM volume had a positive impact on movie sales and supplies; and eWOM valence had a negative impact on movie sales and a positive impact on movie supplies. The number of people who wish to watch a movie was another important variable for movie sales and supplies, and it had a negative impact on the daily movie sales but a positive impact on the daily movie supplies. This study provided a detailed explanation of these results and thus contributed to improving the efficiency of movie suppliers' utilization of online reviews. [ABSTRACT FROM AUTHOR]

International aid to Palestinians is one of the highest in the world, meanwhile, the need for such aid is increasing during time. Under the strict occupation policies, either political, economic or military, the majority of international aid is absorbed by the Israeli economy, which leave the Palestinian economy completely dependent. Four simultaneous equations were estimated using the Three Stage Least Squares to detect the impact of ODA on growth, domestic savings, imports and imports from Israel. Available time series data for Palestine from 2000 to 2019 were estimated. We estimate the international aid propensity to imports and to imports from Israel, besides the impact on growth and domestic savings. We found that ODA associates negatively on growth, crowds out domestic savings and increase imports from Israel more than other imports. ODA marginal propensity to import from Israel is twice and half the marginal propensity to total imports, which that indicates the influence of economic accords and occupation procedures. In addition, Israel absorbs directly one-fourth of each dollar donated to Palestinian economy, and higher absorption is potential in the long run. Correlation has been measured between ODA and Palestinian trade deficit with Israel, and we found that more than 87% of aid ends up in the Israeli economy. A series of recommendations were provided including ending of the unilateral trade union imposed by Israel.

[Display omitted] • Simple and accurate spectrophotometric method for the determination of celecoxib and tramadol. • Principle component regression chemometric model was applied. • The model optimized and validated. Celecoxib and tramadol have been combined in a novel FDA-approved medication to address acute pain disorders requiring opioid treatment when other analgesics proved either intolerable or ineffective. The absorbance spectra of celecoxib and tramadol exhibit significant overlap, posing challenges for their individual quantification. This study introduces a spectrophotometric quantification approach for celecoxib and tramadol using a principle component regression assistive model to assist resolving the overlapped spectra and quantifying both drugs in their binary mixture. The model was constructed by establishing calibration and validation sets for the celecoxib and tramadol mixture, employing a five-level, two-factor experimental design, resulting in 25 samples. Spectral data from these mixtures were measured and preprocessed to eliminate noise in the 200–210 nm range and zero absorbance values in the 290–400 nm range. Consequently, the dataset was streamlined to 81 variables. The predicted concentrations were compared with the known concentrations of celecoxib and tramadol, and the errors in the predictions were evidenced calculating root mean square error of cross-validation and root mean square error of prediction. Validation results demonstrate the efficacy of the models in predicting outcomes; recovery rates approaching 100 % are demonstrated with relative root mean square error of prediction (RRMSEP) values of 0.052 and 0.164 for tramadol and celecoxib, respectively. The selectivity was further evaluated by quantifying celecoxib and tramadol in the presence of potentially interfering drugs. The model demonstrated success in quantifying celecoxib and tramadol in laboratory-prepared tablets, producing metrics consistent with those reported in previously established spectrophotometric methods. [ABSTRACT FROM AUTHOR]

The design of gravity net cage mooring systems is a complex endeavor, which is critical for preventing major accidents caused by mooring system failures. A comprehensive optimization method is proposed to enhance the reliability and performance of the net cage mooring system by integrating static and dynamic phases. The proposed method initiates static simulations based on the catenary theory to refine the initial range of parameters. This preparatory step ensures the subsequent dynamic analysis is carried out based on feasible initial conditions with the lumped mass method. The dynamic simulation captures the complex interactions and behavior of the mooring systems under various environmental conditions. The multi-objective optimization provides feasible solutions with simultaneous consideration of both processes. Three different scenarios are optimized with the forces and motions compared after the time domain analysis, resulting in a satisfactory set of solutions. The results show that variations in the angle of the mooring line of the net cage primarily impact the net cage's movement and volume in different environments. • Optimization is divided into two processes, static and dynamic, static for dynamic to further narrow the range of parameters. • Different mooring line angles have a large effect on the volume residual rate of gravity net cage. • Normalization of the objective function is not needed. [ABSTRACT FROM AUTHOR]

Active noise cancellation of audio signals, which has been the subject of a substantial quantity of research in the past, remains a significant obstacle in many aspects of acoustic signal processing. In a natural environment, the system’s parameters are in constant flux. Consequently, we shall investigate the filtered-x least mean square (FxLMS) algorithm. The adaptive filter is used as a controller to generate an anti-noise signal in the feedforward FxLMS algorithm, which only addressed narrowband and broadband noise. The feedback FxLMS algorithm, on the other hand, enhances the algorithm’s convergence, but cannot eliminate the effect of residual noise’s uncorrelated disturbance. However, both the correlated and uncorrelated disturbances must be under user control. Therefore, a combination of the feedback and feed-forward FxLMS algorithms was employed, which consists of two portions for estimating the primary disturbances and the uncorrelated disturbances. A variable step size algorithm has been employed to attain a balance between system stability and control efficiency. In Akhtar’s method, an external adaptive filter was applied to the feed-forward system in order to estimate a more precise error signal and enhance the performance of the systems. These improvements will improve the algorithm’s ability to control both primary and uncorrelated noise. [ABSTRACT FROM AUTHOR]

This study investigates the relation between exposure to neighborhood violence and student performance, focusing on the spatial effects of crime. Using São Paulo city (Brazil) as case study, we applied multilevel and simultaneous equations models combined with a spatial approach. If the effects of crime can be felt across the city, reducing this type of violence should concern public policies in all districts. Application of the combined methods considered 5th and 9th graders from the public school network. Violence was negatively related to student proficiency. Overall, the spatial behavior of crime should be considered when analyzing the relation between violence and education. Crime prevention should be considered in designing education policies since it can benefit both students in violent areas and those in their surroundings. [ABSTRACT FROM AUTHOR]

The effect of non-monotonic dose dependence of TL intensity on the irradiation dose has been reported in some materials in the past. As opposed to the regular case in which the intensity of the emitted TL light increases monotonically with the applied dose until it reaches saturation, in some reported cases, the light intensity reached a maximum and then declined at higher doses. The effect has been explained by using an energy level model including two electron traps and two hole centers competing with each other, thus yielding the effect. In the present work we show that with the use of certain sets of trap and center parameters, the effect can be seen with a reduced model of one trapping state and two recombination centers. Also, in recent years some experimental results showed more complex non-monotonic dose dependence, namely that following a maximum in the dose-intensity curve, and a certain range of decline, the TL intensity starts to increase again with the dose. We offer a new physical model that may explain this wiggly dose dependence. The energy-level diagram we propose is the same as before, with one electron trap and two kinds of recombination centers, one of which is radiative. In addition, we assume that the high energy radiation can produce more defects in the material which form more radiative recombination centers, this in addition to the filling of new and existing traps and centers by the irradiation. We consider the simultaneous differential equations governing the processes during irradiation, relaxation and heating with the variable dose-dependent concentration of the radiative recombination centers. We solve the equations numerically and by an analytical way with plausible approximations. The wiggly dose dependence results with certain sets of the relevant parameters. • Non-monotonic dose dependence of thermoluminescence (TL) is revisited. • Peak-shaped dose dependence of TL can be explained by a one-trap two-center model. • The model is extended to cases where the dose dependence has a wiggly shape. • The new model includes the creation of radiative centers along with the filling of traps and centers. • Simulations are performed by solving relevant sets of differential equations and analytic method. [ABSTRACT FROM AUTHOR]

The use of clean energy can promote the coordinated development of the economy and the ecological environment. However, few studies have paid attention to the changes in the health status of residents in the process of economic development and energy use. To fill this gap, this paper uses health energy intensity, which refers to the amount of energy consumed per unit of health status (composed of population mortality, maternal mortality, and perinatal mortality), to explore the impact of clean energy (expressed by the share of clean energy consumption in total energy consumption) on economic development and healthy energy intensity. By using the panel data of 30 provinces and cities in China from 2005 to 2019, this paper constructs a simultaneous equation model for empirical analysis from the perspective of the whole country and areas with different income levels. The results show that from the national perspective, in the early stage of clean energy development, the level of economic development and healthy energy intensity increased; however, with the further development of clean energy, the sample period shows that the level of economic development and the healthy energy intensity decreased. Heterogeneity analysis shows that in both high-income and moderate-income areas, clean energy has a U-shaped effect on economic development; but in low-income areas, clean energy has an inverted U-shaped effect on economic development. In high-income and low-income areas, clean energy has an inverted U-shaped effect on healthy energy intensity; but in moderate-income areas, clean energy has a U-shaped effect on healthy energy intensity. China's clean energy market is still in its early stage, and the research conclusions of this paper provide a theoretical basis for the realization of China's clean energy development. [ABSTRACT FROM AUTHOR]

We proposed a simple hyperbolic positioning method that does not require solving simultaneous quadratic equations. Moreover, we introduced the mathematical concept of a "pencil" into analytical calculations in the hyperbolic positioning method for a better understanding. In many recent studies using positioning biotelemetry, the specific procedure for intersection calculation of hyperbolas has rarely been described. This might be one of two major obstacles, with the other being clock synchronisation among receivers, for positioning biotelemetry users, including potential users. We focus only on the intersection calculation in this paper. Therefore, we propose a novel method and introduce the mathematical concept into analytical calculations. The computing performances of the novel method, an analytical method applying the concept of a pencil, and an approximating method using the Newton-Raphson method were compared regarding positioning correctness, accuracy, and calculation speed. In the novel method, hyperbolas were represented using the parameter θ, which was treated as a discrete variant. The finer the tick-width of the parameter θ, the more accurate was its positioning, but it took slightly longer to calculate. By setting the tick-width to 0.01°, a simulated trajectory was correctly and accurately localised, as in the analytical method which always correctly returned the accurate solution. The approximating method has a major limitation concerning correctness. It returns a single solution regardless of two intersections of hyperbolas; however, the positioning is accurate when the hyperbolas intersect at a single point. This study approached one major difficulty in positioning biotelemetry and will help biotelemetry users overcome this drawback with a simple and intuitive understanding of hyperbolic positioning. [ABSTRACT FROM AUTHOR]

SUMMARY: The simultaneous source data obtained by simultaneous source acquisition contain crosstalk noise and cannot be directly used in conventional data processing procedures. Therefore, it is necessary to deblend the blended wavefield to obtain the conventionally acquired single-shot recordings. In this study, we propose an iterative inversion method based on the unsupervised deep neural network (UDNN) to deblend the simultaneous source data from a denser shot coverage survey (DSCS). In the common receiver gather (CRG), the coherent effective signals in the blended data of the primary and secondary sources are similar. We exploit the excellent nonlinear optimization capability of the U-net network to extract similar coherent signals from the blended data of the primary and secondary sources by minimizing the total loss function. The proposed UDNN method does not need to use the raw unblended data as label data, which solves the problem of missing label data and is suitable for deblending the simultaneous source data in different work areas with complex underground structures. One synthetic data and one field data examples are used to prove that the proposed method can suppress crosstalk noise and protect weak effective signals effectively, and achieve good effectiveness for the separation of simultaneous source data. [ABSTRACT FROM AUTHOR]

Propensity score is widely used to estimate treatment effects in observational studies. The covariate adjustment using propensity score is the most straightforward method in the literature of causal inference. In this article, we estimate the survival treatment effect with covariate adjustment using propensity score in the semiparametric accelerated failure time model. We establish the asymptotic properties of the proposed estimator by simultaneous estimating equations. We conduct simulation studies to evaluate the finite sample performance of the proposed method. A real data set from the German Breast Cancer Study Group is analyzed to illustrate the proposed method. [ABSTRACT FROM AUTHOR]

While there have been separate studies on FDI–growth and FDI–welfare links, few or no studies exist that simultaneously examine FDI–growth–welfare link at aggregate or sectoral level. This study adopted a recent causality method and a simultaneous equation model to analyse the effect of FDI on sectoral growth and welfare using a cross-sectional panel of 23 countries, spanning 1990‒2019. The study accounted for sectoral spillover effects, heterogeneity, simultaneity and cross-sectional dependence in our model. Findings suggest that FDI promotes output in the manufacturing and services sectors more than in the agriculture sector, while it fosters human development (HD). Also, the results show that while HD promotes output in the agricultural sector, it deters output in the manufacturing and service sectors. Further findings show that only agricultural output improves HD among the countries. This study therefore recommends that for African countries to improve sectoral output growth and welfare using FDI as a catalyst, a policy framework toward attracting more FDI into the three key sectors (especially in the manufacturing and services) is desirable for increased output and human development in Africa. [ABSTRACT FROM AUTHOR]

In order to quantitatively analyze the synergistic relationship between the digital economy and high-quality development, the author proposes a measure of the coupling and coordination of China's digital economy and high-quality development. Based on the data of 271 prefecture-level and above cities in China from 2016 to 2021, the coupling coordination degree model is used to examine the coupling relationship between the digital economy and high-quality development. The result shows that China's digital economy and high-quality development are highly coupled, with an average coupling value of 0.9227. Conclusion. This study reveals the characteristics and facts of the coupling and coordination relationship between China's digital economy and high-quality development and provides useful policy inspiration for the central and regional formulation of differentiated digital economy development policies and high-quality development strategies. [ABSTRACT FROM AUTHOR]

Estimating the pose of a calibrated camera relative to a 3D point set from one image is an important task in computer vision. Perspective-n-Point algorithms are often used if perfect 2D-3D correspondences are known. However, it is difficult to determine 2D-3D correspondences perfectly, and then the simultaneous pose and correspondence determination problem is needed to be solved. Early methods aimed to solve this problem by local optimization. Recently, several new methods are proposed to globally solve this problem by using branch-and-bound (BnB) method, but they tend to be slow because the time complexity of the BnB-based methods is exponential to the dimensionality of the parameter space, and they directly search the 6D parameter space. In this paper, we propose to decompose the joint searching into two separate searching processes by introducing a rotation invariant feature (RIF). Specifically, we construct RIFs from the original 3D and 2D point sets and search for the globally optimal translation to match these two RIFs first. Then, the original 3D point set is translated and matched with the 2D point set to find a globally optimal rotation. Experiments on challenging data show that the proposed method outperforms state-of-the-art methods in terms of both speed and accuracy. [ABSTRACT FROM AUTHOR]

Currently, the User-PC computingsystem (UPC) has been studied as a low-cost and high-performance distributed computing platform. It uses idling resources of personal computers (PCs) in a group. The job-worker assignment for minimizing makespan is critical to determine the performance of the UPC system. Some applications need to execute a lot of uniform jobs that use the identical program but with slightly different data, where they take the similar CPU time on a PC. Then, the total CPU time of a worker is almost linear to the number of assigned jobs. In this paper, we propose a static assignment algorithm of uniform jobs to workers in the UPC system, using simultaneous linear equations to find the lower bound on makespan, where every worker requires the same CPU time to complete the assigned jobs. For the evaluations of the proposal, we consider the uniform jobs in three applications. In OpenPose, the CNN-based keypoint estimation program runs with various images of human bodies. In OpenFOAM, the physics simulation program runs with various parameter sets. In code testing, two open-source programs run with various source codes from students for the Android programming learning assistance system (APLAS). Using the proposal, we assigned the jobs to six workers in the testbed UPC system and measured the CPU time. The results show that makespan was reduced by 10 % on average, which confirms the effectiveness of the proposal. [ABSTRACT FROM AUTHOR]

Upgrading urban industrial structure and improving urban land use ecological efficiency is one of the most important tasks in the construction of urban ecological civilization. In this study, we constructed an evaluation index system based on the implications of urban land use ecological efficiency and used the SBM-undesirable model and kernel density estimation method to quantitatively describe the spatial differences in land use ecological efficiency in 108 cities along the Yangtze River Economic Belt from 2003 to 2018. Furthermore, this study used the spatial simultaneous equation model to explore the spatial spillover effects of the interaction between the urban land use ecological efficiency and the upgrading of urban industrial structure in this region. The results showed that: ① From 2003 to 2018, the overall level of urban land use ecological efficiency in the Yangtze River Economic Belt was low, presenting a flat ‘N’ evolution characteristic. Among them, in the lower reaches of the Yangtze River from 2003 to 2012, urban land use ecological efficiency was always at the forefront of the entire watershed, while from 2012 to 2018, the growth rate of urban land use ecological efficiency in the upper and middle reaches of the Yangtze River was significantly higher than that in the lower reaches of the Yangtze River, and the urban land use ecological efficiency in the upper, middle, and lower reaches of the Yangtze River presented regional heterogeneity. ② From 2003 to 2018, the urban land use ecological efficiency in the Yangtze River Economic Belt showed a polarized pattern in geographical space, and the regional differences showed a decreasing trend. The urban land use ecological efficiency in the upper, middle, and lower reaches of the Yangtze River Economic Belt showed a trend of first increasing and then decreasing, first decreasing and then stabilizing, and gradually decreasing, respectively. ③ There was a positive interaction effect between urban land use ecological efficiency and urban industrial structure upgrading in the Yangtze River Economic Belt. Urban industrial structure upgrading was in a relatively dominant position in the mutual promotion relationship, and the two had a significant spatial spillover effect and a significant spatial interaction effect in geographical space. The upper, middle, and lower reaches of the Yangtze River Economic Belt also had mutual effects. However, regional heterogeneity existed in the spatial interaction between urban land use ecological efficiency and urban industrial structure upgrading. Therefore, China should promote land stock management according to local conditions in the future, innovating urban land use models to improve the green development level of urban land use and further coordinating the mutual promotion and spatial interaction between urban land use ecological efficiency and urban industrial structure upgrading within and between regions to promote the interaction between them. [ABSTRACT FROM AUTHOR]

Digital technologies can be a critical channel in boosting economic growth and achieving Sustainable Development Goals. During crises like COVID-19, digitalization can facilitate the reception of remittances from relatives and friends. We analyze the effects of migrant remittances (MRs) on economic growth in ECOWAS countries with a special emphasis on the role of digitalization. The simultaneous equations and the seemingly unrelated regression method are used with data spanning from 1980 to 2017. Findings show that digitization is not a channel for transmitting the effects of MRs on economic growth in ECOWAS countries. However, digitalization constitutes a catalyst of the effects of MRs on economic growth in non-WAEMU countries, while it does not in WAEMU (a sub-regional block of ECOWAS). Nevertheless, remittances contribute to human capital accumulation, investment, and consumption in WAEMU countries. Policies aiming at strengthening digitization are welcome to foster the effect of MRs on countries' economies in ECOWAS, in general, and WAEMU in particular. [ABSTRACT FROM AUTHOR]

This study analyzed the relationship between inequality, economic growth, unemployment (endogenous variables), and other exogenous variables affecting the relationship. The panel data included 154 cities and regencies in Sumatera Island of Indonesia for ten consecutive years (2011-2020). Data were analyzed using simultaneous equations models for econometrics. Our findings confirmed (1) a negatively correlated, significant, and simultaneous two-way relationship between inequality and growth and (2) a negatively correlated and significant two-way causality between economic growth and unemployment. However, the relationship between inequality and unemployment was not significant. The limitation of the study was that it only used a simultaneous approach using three equations (inequality, growth, and unemployment); hence, other models may be developed using the other endogenous variables. Our findings will be helpful to make better policies to reduce inequality and unemployment and encourage economic growth, especially for the local governments in Sumatera Island. [ABSTRACT FROM AUTHOR]

We investigate how the physical water environment shapes water conservation norms among farmers in the High Plains-Ogallala Aquifer, the largest source of groundwater in the United States. We approach these questions in terms of cultural adaptation to the physical environment, comparing irrigators with dryland farmers using survey and environmental data. We use the values-beliefs-norms (VBN) framework to develop a conceptual model to integrate the physical water context as an exogenous explanation of water conservation norms. Grouped simultaneous equations models indicate a limited form of cultural adaptation in the region that, from a biological perspective, could be considered evidence of mal-adaptation. Both irrigators and dryland operators in more water-rich environments hold stronger water conservation norms and those in more arid environments hold weaker water conservation norms. For irrigators, the relationship between the water context and norms is partially mediated by worldviews: irrigators in more water scarce contexts tend to hold more ecocentric worldviews that motivate conservation. The findings suggest the importance of considering farmers' practices (dryland farming or irrigation) and their places (physical water context) in shaping their decision-making in an integrated socio-ecological context. • Examined how physical water context shapes cultural adaptation among farmers. • Found evidence of mal-adaptation. • Physical water context influences irrigators and dryland farmers differently. • Farmers in more water-rich environments hold stronger water conservation norms. • Farmers in more arid environments hold weaker water conservation norms. [ABSTRACT FROM AUTHOR]

Background and Aim: Trijardy XR® consisting of empagliflozin, linagliptin, and metformin hydrochloride, a fixed-dose combination (tablets) that improves glycemic control in individuals with diabetes mellitus (type 2). The present work presents four spectrophotometric methods that are quick, effortless, accurate and reproducible for the concurrent assessment of the ternary mixture. Materials and Methods: The 1st approach works on the principle of solving established equations (simultaneous) by measuring absorbance at 224.6, 226 and 237.2 nm for empagliflozin, linagliptin and metformin hydrochloride, respectively. The second method namely ratio difference spectroscopy works by measuring the difference in amplitude at two different wavelengths in the ratio spectra. Whereas, the derivative ratio spectrum zero-crossing approach (third approach) relied on the utilization of the derivative ratio signals at zero-crossing locations. The fourth approach is the double divisor-ratio spectra derivative approach in which the first derivative of ratio spectrum was acquired and the concentrations of all 3 drugs in their combination were quantified. Results and Discussion: All the three drugs exhibited excellent linear correlation in the concentration series of 2-10 µg/ml for simultaneous equation method and 0.5-10 µg/ml for all the other methods with an exceptional correlation coefficient value. Furthermore, the projected approaches were validated as per ICH strategies and which displayed good precision, accuracy and sensitivity. Conclusion: The developed spectrophotometric approaches when compared to other analytical procedures are regarded to be more cost-effective because they do not require expensive solvents or sophisticated instruments. Therefore, the projected methods could be effectively employed for the concurrent assessment of empagliflozin, linagliptin and metformin hydrochloride in ternary mixture. [ABSTRACT FROM AUTHOR]

Articulated slab bridges have been widely used by transportation administration for short-to-medium span bridges because of their good economy, convenient construction, and environmental advantages, while the presence of shear keys increases the complexity of structural behavior. Developing more reasonable analysis approaches of quick assessment, pre-design, and hand calculations for the articulated slab bridges is a challenge because of the peculiar shear key mechanism. This paper is devoted to presenting a recursive algorithm, based on the force equilibrium conditions of each individual slab, thus resulting in simultaneous equations of the transfer matrix method (TMM). In this procedure, the state vector is an array composed of vertical displacement, shear force, unit constant; and the transfer matrix contains the bending and torsional stiffness parameters of simply supported slabs. Then, the influence line of transverse load distribution (TLD) is calculated for each slab by introducing boundary conditions. To validate and verify the efficiency of the TMM algorithm, a transversely prefabricated void slab bridge with a span of 20 m is considered as a case study. The traditional force (FM) and finite element (FEM) methods are used for comparison and validation. It is demonstrated that the TMM can provide good results with higher algorithm efficiency by exempting the modeling tasks in FM and FEM and capture variations in TLD along the bridge's span. In addition, the influence of the span length and relative stiffness coefficient of slabs on the TLD of articulated slab bridges are analyzed from the parametric analysis. [ABSTRACT FROM AUTHOR]

This paper is aimed at verifying the existence of the systematic contradictions between inventory efficiency (IE) and capacity utilization (CU), two critical indicators of firm performance, in the manufacturing industry and the role of information sharing with supply chain partners in weakening the contradictions through empirical analysis. Raw material and finished goods inventory are studied respectively, and the underlying mechanism is established for each. With a cross-sectional dataset, we estimate systems of simultaneous equations with the three-stage least square (3SLS) method to investigate the interacting effects and further conduct the estimation on subsamples grouped by the moderator to study the moderating effects. The study confirms a significant two-way negative relationship between IE and CU and documents a significant negative moderating effect of sharing demand forecast with raw material suppliers on the interaction between raw material inventory efficiency (RMIE) and CU. The findings suggest managers keep in mind that the two operational objectives cannot be achieved at the same time dealing with supply chain uncertainty and take into account the costs and benefits of capacity and inventory when choosing strategies. They can also improve this situation by cooperating with supply chain partners to share information like demand forecast with them. [ABSTRACT FROM AUTHOR]

Crop residue burning (CRB) poses a serious threat to the climate, soil fertility, human health and wellbeing, and air quality, which increases mortality rates and slumps agricultural productivity. This study conducts a pan-India analysis of CRB burning based on the spatial characteristic of crop residue management practices and analyzes the linkage among health, agriculture value addition, and regional finance using the simultaneous equation to find the causality and panel quantile regression for direct effect and intergroup difference. We discuss some of the alternative crop residue management practices and policy interventions. Along with in situ management, this paper discusses ex situ crop residue management (CRM) solutions. The ex situ effort to manage crop residue failed due to the scarcity of the supply chain ecosystem. Force of habit and time constrain coupled with risk aversion have made farmers reluctant to adopt these solutions. Our results show that financial viability and crop residue have bidirectional causality; therefore, both the central and state governments must provide a financial solution to lure farmers into adopting residue management practices. Our analysis shows that framers are likely to adopt the management solution (farmers have some economic benefits) and are reluctant to adopt the scientific solution because the scientific solution, such as "pusa decomposer", is constrained by the weather, temperature, and humidity, and these parameters vary throughout India. [ABSTRACT FROM AUTHOR]

We study integral points on the quadratic twists \mathcal {E}_D:y^2=x^3-D^2x of the congruent number curve. We give upper bounds on the number of integral points in each coset of 2\mathcal {E}_D(\mathbb {Q}) in \mathcal {E}_D(\mathbb {Q}) and show that their total is \ll (3.8)^{\operatorname {rank} \mathcal {E}_D(\mathbb {Q})}. We further show that the average number of non-torsion integral points in this family is bounded above by 2. As an application we also deduce from our upper bounds that the system of simultaneous Pell equations aX^2-bY^2=d,\ bY^2-cZ^2=d for pairwise coprime positive integers a,b,c,d, has at most \ll (3.6)^{\omega (abcd)} integer solutions. [ABSTRACT FROM AUTHOR]