Dispersion Parameters Research Articles

Multivariate Generalized Linear Mixed Models for Count Data

Univariate regression models have rich literature for counting data. However, this is not the case for multivariate count data. Therefore, we present the Multivariate Generalized Linear Mixed Models framework that deals with a multivariate set of responses, measuring the correlation between them through random effects that follows a multivariate normal distribution. This model is based on a GLMM with a random intercept and the estimation process remains the same as a standard GLMM with random effects integrated out via Laplace approximation. We efficiently implemented this model through the TMB package available in R. We used Poisson, negative binomial (NB), and COM-Poisson distributions. To assess the estimator properties, we conducted a simulation study considering four different sample sizes and three different correlation values for each distribution. We achieved unbiased and consistent estimators for Poisson and NB distributions; for COM-Poisson estimators were consistent, but biased, especially for dispersion, variance, and correlation parameter estimators. These models were applied to two datasets. The first concerns a sample from 30 different sites collected in Australia where the number of times each one of the 41 different ant species was registered; which results in an impressive 820 variance-covariance and 41 dispersion parameters are estimated simultaneously, let alone the regression parameters. The second is from the Australia Health Survey with 5 response variables and 5190 respondents. These datasets can be considered overdispersed by the generalized dispersion index. The COM-Poisson model overcame the other two competitors considering three goodness-of-fit indexes, AIC, BIC, and maximized log-likelihood values. As a result, it estimated parameters with smaller standard errors and a greater number of significant correlation coefficients. Therefore, the proposed model is capable of dealing with multivariate count data, either under- equi- or overdispersed responses, and measuring any kind of correlation between them taking into account the effects of the covariates.

Study the effect of nano NiCo2O4 doping on the optical and dielectric properties of PMMA/PEO/MWCNTs

In this study, NiCo2O4 nanoparticles were prepared using a hydrothermal process and examined by x-ray diffraction. After that, using the casting technique, blends of polymethyl methacrylate (PMMA)/poly(ethylene oxide) (PEO) were loaded with multi-walled carbon nanotubes (MWCNTs) and different amounts (x) of NiCo2O4 nanoparticles. The obtained blends were characterized using X-ray diffraction and scanning electron microscopy techniques. Utilizing diffuse reflectance measurements, various optical parameters, including energy gap, refractive index, extinction coefficient, optical dielectric constant, optical conductivity, and nonlinear optical parameters, were investigated. Following incorporation of MWCNTs/NiCo2O4 in the blend, the transmittance of the PMMA/PEO blend (90 %) displayed a drop reaching 21 %, the reflectivity and refractive index increased. The direct/indirect optical band gap values of PMMA/PEO (5.07/4.8 eV) decreased attaining 4.96/4.54 eV for the blend with 2.5 wt% NiCo2O4. The optical conductivity greatly enhanced, and the linear and nonlinear optical parameters increased as the amount of NiCo2O4 doping increased. The dispersion parameters for all blends were also calculated. Fluorescence spectra (FL) measurements revealed a reduction in the FL intensity with increasing the NiCo2O4 content (x). Through the dielectric measurements, the impact of increasing NiCo2O4 content on the ac conductivity, dielectric properties, energy density, and electric modulus was analyzed for all blends. Remarkably, a significant increase in AC conductivity was obtained upon loading with 1.5 wt% NiCo2O4. Overall, variation in the dielectric and optical features of the PMMA/PEO/MWCNTs/x wt.% NiCo2O4 blends makes them appropriate for optoelectronic and energy storage applications.

Clinical Presentation and Etiologic Diagnosis of Disorders of Sex Development in Children in Senegal

Introduction: Disorders of Sex Development (DSD) refer to situations where chromosomal, gonadal or anatomical sex is atypical. We aimed to describe the baseline characteristics on clinical and etiological diagnosis of DSD in Senegalese children. Methods: This retrospective cohort study over a period of 8 years (2015-2022) included all children aged 0 to 18 years followed for DSD at the pediatric endocrinology department of NCHAR in Dakar. Sociodemographic clinical, paraclinical (genetics, imaging, hormonal) parameters were collected and analyzed with Epi Info 7.2. The description was made using position and dispersion parameters and illustrations in the form of appropriate tables and graphs. Bivariate analysis was used for associations between variables, with an alpha error risk of 5% and a CI of 95%. All ethical rules have been respected. Results: We included 102 DSD cases. Only 61 patients (59.80%) had a genetic diagnosis. Mean age at diagnosis was 31.2 ± 46.6 months. Rearing sex of child was male in 35 cases (57.38%) and female in 22 cases (36.06%) and undetermined in 4 cases (6.56%). Based on karyotype analysis, 31(50.82%) of children had 46,XY DSD, 27 (44.26%) had 46,XX DSD and three (4.92%) children with sex chromosome DSD. Etiologies were dominated by congenital adrenal hyperplasia (81.48%) and androgen insensitivity (38.71%) in 46,XX and 46,XY DSD respectively. External masculinization score > 4, palpation of a gonad, a phallus length > 2.5, a single urogenital orifice as well as ultrasound sex were associated with the XY karyotype. Conclusion: Health care professional and medical students should be trained for early diagnosis. A national guideline should be developed for diagnosis and management of DSD during and beyond the pediatric age group, and adapted to evidence and available resources. This can only be achieved if the management of DSD is supported by universal health insurance.

Factors driving FIFA world cup 2022 viewership ratings in mainland China: marketing outlooks for FIFA world cup 2026.

The FIFA World Cup is not only the most lucrative athletic event globally, but it also functions as a platform for promoting peace owing to FIFA's new vision. Nevertheless, the determinants of TV viewership ratings, especially in the Chinese market, which is a critical revenue stream for FIFA TV broadcasting, are still unsolved. Using a distributional regression, this study aimed to quantify the dynamics of viewership ratings for the FIFA World Cup 2022 in mainland China. The CCTV viewership ratings were modeled using 12 covariables related to Chinese TV consumer behavior. Given the data structure, a Logit Normal regression model was chosen to fit the location and dispersion parameters of viewership ratings to explanatory variables. In the fitted heteroscedastic model, the viewership ratings dynamics in mainland China were driven by the match kick-off time: . In addition, the model captures the factors that influence the variations in viewership ratings: (if, FIFA World Cup champion = "Yes") + 0.004 × FIFA world ranking]. Thus, it shows that the FIFA World Cup champions tamp down such variations, leading to a more stable viewing behavior among Chinese consumers. Time- and team-sensitive strategies are proposed to aid in crafting uncertainty-suppressing business decisions for the FIFA World Cup 2026. Ultimately, in the more insecure 2020s, a broader live coverage of the FIFA World Cup would be invaluable for promoting peace.

Tailoring the linear and nonlinear optical properties of PVC/PE blend polymer by insertion the spindle copper nanoparticles

PVC/PE polymer nanocomposites were synthesized with 0–3 wt% copper (Cu) nanoparticles via melt extrusion. XRD analysis showed characteristic peaks corresponding to crystalline PVC, PE, and Cu phases. FTIR confirmed the presence of signature vibrational modes of PVC and PE. Optical studies revealed tunable light absorption, refractive index, dielectric response, and bandgap by tailoring copper content. The composites displayed enhanced linear and nonlinear optical susceptibilities, with potential applications in photonics. Optical absorption studies revealed a redshift in bandgap from 3.38 eV to 2.19 eV as Cu concentration increased from 0 to 3%, indicating enhanced visible light absorption. The real dielectric constant rose from 1.3527 to 1.4578 at 190 nm wavelength when Cu content was raised from 0 to 3%. Imaginary dielectric constant exhibited a stepwise enhancement from 2.43 × 10−3 to 3.97 × 10−3 at 190 nm with increasing Cu loading up to 3 %. The nonlinear refractive index varied from 1.2 × 10−8 cm2/W to 2.1 × 10−8 cm2/W across 500–900 nm wavelengths for 0–3% Cu. Meanwhile, the dispersion parameters including, the single oscillator energy (Eo) and the dispersion energy (Ed) were extracted. The relaxation time of the studied samples were extracted, which decreased after the insertion the nanofillers. The outcomes revealed that Cu nanoparticles' doped films favor a high-speed optoelectronic device more than the pristine film.The results demonstrate tunable optical and dielectric characteristics, underscoring the potential of Cu-based PVC/PE nanocomposites.

Doping and precoating by Cu-metal and annealing impacts on some physical properties and applications of MnS thin films

We prepared thin films of manganese sulfide (MnS) using a thermal evaporation technique. These films were pre-coated and doped with Cu ((MnS)1-xCux, x = 0.05 g). A lot of work was done on these films using X-ray diffraction (XRD), field emission scanning electron microscopy (FE-SEM), UV/VIS/NIR spectrophotometry, and a two-probe approach to figure out their structure, shape, optical properties, and electrical properties. We investigated various factors including the optical energy gap (Eg), refractive index (n), extinction coefficient (k), Urbach energy (Eu), dielectric constants (εr), dispersion parameters, activation energy (ΔE), mobility, photocatalytic analysis, and Seebeck coefficient. The XRD analysis showed that the thin films were amorphous. The direct optical energy gaps of the pure, Cu pre-coated layer, and Cu-doped MnS films were measured at 3.17 eV, 1.88 eV, and 2.45 eV, respectively. Annealing the films at different temperatures showed normal refractive index dispersion in the NIR region. The addition of copper, both as a pre-coating layer and as doping, resulted in a decrease in film resistivity, indicating their semiconducting nature. FE-SEM analysis provided valuable insights into the morphology of the thin films, revealing a uniform and smooth surface. The electrical characteristics showed that film resistivity decreased with copper addition, confirming enhanced conductivity. These properties hold significance in the development of absorber layers for second-generation solar cells, thermoelectric characteristics, and photocatalysis applications.

Application of non-destructive fast methods for quality assessment of sunflower oil

The sunflower oil is pressed from the seeds of the sunflower plant (Helianthus annuus). It contains high amounts of the essential fatty acid, linoleic acid. Sunflower oil is commonly consumed in foods. The quality of sunflower oil depends on the quality of the sunflower seeds to be processed, the storage conditions of the seeds before pressing and the refining conditions. The standard chemical methods used to determine the chemical content of the oils are usually time-consuming,labor-intensive and expensive. Therefore, we have tested four physical methods measuring refractive indices and their dispersion curves, color parameters, UV-VIS spectroscopic and fluorescence spectra that are related to the chemical structure and composition of the sunflower oils. The refractive indices of the samples were measured using a laser refractometer at wavelengths of 405 nm, 447 nm, 532 nm and 656 nm. The dispersion curves and the dispersion parameters were approximated using one-term Sellmeier model. The color parameters were obtained using a Lovibond PFX 880 spectrophotometer. The values for the refractive indices were compared to these, obtained by a standard method using the Abbe refractometer. These methods are fast, easy to perform and do not require any additional chemical agents. Four groups of sunflower oils – cold pressed, oil with added antioxidants and commercially refined and nonrefined sunflower oil, were investigated.

Electrocardiographic characteristics of bladder cancer patients receiving preoperative chemotherapy combined with immunotherapy.

Patients treated with preoperative chemotherapy and immunotherapy for bladder cancer may be at increased risk of cardiotoxicity and electrophysiological abnormalities. This study aimed to analyze their electrocardiographic (ECG) alterations. Patients with bladder cancer who were hospitalized and receiving tislelizumab plus nab-paclitaxel (TnP) were enrolled prospectively. ECG, cardiac biomarkers, and echocardiography were performed at baseline and the end of TnP. A total of 60 patients (76.7% males), including 30 muscle-invasive and 30 non-muscle-invasive bladder cancer, received three or four cycles of TnP, respectively. Hypertension was the commonest comorbidity (41.7%), and 25 patients (41.7%) were prescribed cardiovascular drugs. In comparison with baseline characteristics, cardiac troponin I (cTnI) and N-terminal pro-brain natriuretic peptide (NT-proBNP) were within normal ranges after TnP. However, echocardiographic parameter of left ventricular ejection fraction slightly decreased after TnP (62.81 ± 3.81% to 61.10 ± 4.37%, p = .011). The incidence of abnormal ECG increased from 65.0% at baseline to 76.7%, of which only a higher prevalence of fragmented QRS (fQRS) was observed (33.3% to 50.0%, p = .013; mainly in inferior leads). ECG parameters of QT dispersion (QTd) were prolonged significantly after the regimen (39.50 ± 11.37 to 44.20 ± 15.85 ms, p = .019). In bladder cancer patients receiving preoperative chemotherapy combined with immunotherapy, the main ECG abnormality was fQRS and QTd, with relatively normal cardiac biomarkers and echocardiographic parameters. Regular ECG screening should be carried out carefully to detect potential cardiotoxicity in the long-term follow-up.

Rheological investigations on frequency selective surface carbon composite microwave absorber.

A high-performance stealth platform is one of the crucial requirements in defence technology that could practically be realized by building effective microwave frequency selective surface (FSS) absorbers. Herein, we report the design and manufacturing of an absorber by tuning the rheology of cell architecture. Initially, a fan-shaped cell (10.4 mm2) was designed for its surface and bulk rheology. The FSS overlayer composition was investigated using SEM, EDX, and XRD and tuned for 0.25% carbon: 1.5% silver to achieve the ink resistivity ∼255 Ω □-1. The bulk rheology was optimized for air (Roha) spacer (thickness ∼2.8 mm), interlayer dielectrics (0.2 mm each), carbon composition (5%), and cell dimension (10.2 mm). Analyses are presented for absorption loss (RC, dB), bandwidth (GHz), resonance dispersion, and constitutive (ε, μ) parameters, compounded with an equivalent circuit model with the settings R = 273.55 Ω, L = 2.25 nH, C = 0.057 pF and the Fabry-Perot reactance mode@10 GHz. The bi-modal response was investigated for induced polarization, electromagnetic fields, volume power distribution, and angular (Θ = 0°-50°) and rotational stability (Φ = 0°-90°) against TE/TM incidences. The FSS pattern was implemented using a screen printing technique to fabricate a prototype absorber and subjected to the free space measurements in an anechoic chamber. The prototype behaviour was found to be commensurate with the simulated performance, thereby achieving a figure of merit of RC ∼-25 dB@10 GHz, accessible bandwidth 4 GHz (in X band) by using the thickness of 0.057 λ0. Details are presented in this study.

Microstructural Abnormalities in the Contralateral Normal-appearing White Matter of Glioblastoma Patients Evaluated with Advanced Diffusion Imaging.

Glioblastoma patients develop recurrence in the opposite hemisphere far from the primary tumor site even after complete resection. This is one of the main reasons for short disease survival. Our aim in this study is to detect microstructural changes in the contralateral hemisphere of glioblastoma patients using different diffusion models with the fully automated tract-based spatial statistics (TBSS) method. Fourteen right-sided and eleven left-sided glioblastoma patients without any treatment and eighteen age- and gender-matched controls were included in the study. Multi-shell diffusion weighted images were created with a 3T MRI device. After various preprocessing steps, images of fractional anisotropy (FA), mean diffusivity (MD), axial diffusivity (AD), radial diffusivity (RD), axial kurtosis (AK), mean kurtosis (MK), radial kurtosis (RK), intracellular volume fraction (ICVF), orientation dispersion index (ODI), and isotropic water fraction (ISO) were obtained. TBSS was used to compare diffusion tensor imaging, diffusion kurtosis imaging, and neurite orientation dispersion and density imaging parameters of right- and left-sided glioblastoma patients with the control group for the contralateral hemisphere. Both right-sided and left-sided glioblastoma patients have shown an increase in MD and ODI in the contralateral hemisphere. While right-sided glioblastoma patients showed an increase in RD, AD, and ISO in a more limited area in the contralateral hemisphere, left-sided glioblastoma patients showed an increase in MK and AK. FA, ICVF, and RK did not show any difference in both groups. There are microstructural changes in the contralateral hemisphere in glioblastoma patients, and these changes differ between right-sided and left-sided glioblastoma patients.

Design of optical frequency comb based on dual frequency pumped normal dispersion silicon carbide microresonator

<sec>The scheme of generating optical frequency comb (OFC) mainly includes mode-locked laser, electro-optic modulation comb, and nonlinear Kerr micro-resonator comb. The OFC with frequency spacing on the order of 10–200 GHz can be employed in optical communication, microwave photonics, and other fields. Silicon carbide (SiC) has aroused the considerable research interest in integrated nonlinear photonics owing to its high second nonlinear coefficient and third order nonlinear coefficient, low optical loss, without multiphoton absorption loss owing to the wide bandgap. Single soliton microcomb in anomalous group velocity dispersion regime based on a 4H-SiC-on-insulator thin film has been demonstrated with the relative lower pump to comb efficiency, while the OFC in normal dispersion regime based on the SiC microresonator has not been reported. The pump conversion efficiency of OFC in the normal dispersion regime is high, and the pump frequency detuning range for the OFC generation is large, which is conducive to the OFC generation and long-term stable operation. Since there is no modulation instability effect in normal dispersion regime, the key to generating the OFC in normal dispersion regime is that the initial state needs the assistance of a multi-frequency laser (or four-wave mixing sideband). The phase-locked dual-frequency laser can be regarded as a pulse pump laser source with wide pulse duration, which can be realized by integrated distributed feedback laser.</sec><sec>In this paper, a scheme of generating OFC by pumping the normal dispersion SiC microresonator with phase locked dual-frequency laser is proposed. The flat normal dispersion in 1550 nm band is realized through dispersion engineering of the SiC microresonator. The effective mode field area of the TE<sub>0</sub> fundamental mode at 1550 nm in the optimized SiC ridge waveguide is about 0.94 μm<sup>2</sup>, and the nonlinear coefficient is about 3.69 <inline-formula><tex-math id="M2">\begin{document}$ {{\mathrm{W}}}^{-1}{\cdot} {{\mathrm{m}}}^{-1} $\end{document}</tex-math><alternatives><graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="3-20231442_M2.jpg"/><graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="3-20231442_M2.png"/></alternatives></inline-formula>. Meanwhile, dispersion parameters of the microresonator with 100 GHz FSR are also obtained. The OFC generation pumped by a phase-locked dual-frequency laser based on normal dispersion SiC microresonator is simulated through using the Lugiato-Lefever equation. The evolution process of the OFC in time and frequency domain related to the pump detuning is studied. The effects of several parameters such as the pump power, microresonator waveguide loss, microresonator dispersion, proportion of the dual-frequency laser, and the frequency interval of dual-frequency laser on the performance of the OFC are also investigated. The conclusions can be obtained through the OFC generation simulation as follows, 1) When the microresonator waveguide loss is larger, the pump detuning range for the OFC generation becomes smaller, and the pulse peak power under the same pulse intensity filling rate decreases. 2) When the input pump power is larger, the pump detuning range for the OFC generation becomes larger, the pulse peak power under the same pulse intensity filling rate increases, and the corresponding spectrum becomes wider. 3) With the increase of absolute dispersion value, the spectrum bandwidth of the generated OFC decreases obviously. 4) The power proportion of dual-frequency laser has little influence on the OFC generation. 5) The frequency spacing of the generated OFC can be tuned through changing the frequency spacing of the two phase-locked lasers with integral multiple of free spectral range.</sec><sec>The OFC with spectrum bandwidth of about 70 nm can be generated in a range of 1500—1600 nm through the simulation. The simulation results are beneficial to promoting the research and practical application of high repetition rate broadband optical frequency comb in a 1550 nm band based on the normal dispersion silicon carbide microresonator.</sec>

Оценка параметров моделей подземных вод с помощью искусственных нейронных сетей

The paper investigates the possibility of solving the inverse problem using artificial neural networks. To demonstrate the approach, an example is considered consisting of an analytical model of the transfer of pollutants from a point source to a stationary flow field. The model was used to model the behavior of groundwater systems at different values of the dispersion coefficient. Next, a set of controlled multilayer neural networks of direct propagation was trained to evaluate, determine, and select a parameter corresponding to given concentration histories. The results obtained in the work showed satisfactory accuracy of neural network estimates, which confirms the stability of the approach to data analysis in field experiments. When training four artificial neural networks of a controlled, multilayer and direct type, it was found that each of them specialized in a wide range of values. This led to more accurate predictions compared to the case of training a single network over the entire range of values. In addition, the paper shows the ability of a neural network to identify the dispersion parameter at a given concentration under the influence of “noise”. An analysis of the topologies of the applied neural networks has established that the presence of 10 hidden nodes is sufficient to ensure a satisfactory level of calculation accuracy

유창성 장애의 언어치료 관련 경시적 계수자료의 유연한 분석

In this study, the goal was to apply a flexible and easy-to-manage analysis method through a model that includes a dispersion parameter in the longitudinal analysis method of count data. In the analysis of count data, it may be inconvenient to change the statistical model depending on whether there is under- or over-dispersion. To compensate for these weaknesses, We have applied a statistical method including a dispersion parameter to the statistical model. The count data covered were included in the diagnosis of fluency disorders and the evaluation of the effectiveness of speech therapy. but research on speech-language therapy is limited by being conducted on small numbers of subjects for several reasons. Therefore, statistical analysis methods that work only on large samples, are complex, or require excessive calculations in the model fitting process were not appropriate for the field. With this background, we applied the Conway-Maxwell Poisson model to longitudinal data analysis of fluency disorders. We evaluated whether the model that reflects the level of data dispersion in the model was consistent with the speech therapy data for fluency disorders by comparing it to the existing Poisson mixed model and linear mixed model. In particular, the Conway-Maxwell Poisson model had the advantage of reflecting well when the degree of dispersion was different for each group or specific subgroup.

The spectral properties and dispersion parameters of electrospun nanofibers Poly(vinyl alcohol/ Poly(acrylamide)

Electrospun nanofibers based on polyvinyl alcohol (PVA), polyacrylamide (PAAm), and a PVA-PAAm blend (50/50 wt.%) were effectively made a room temperature(RT) and a voltage of (12kV). The products were studied using Field Emission Scanning Electron Microscope (FESEM), X-ray diffraction (XRD), Fourier-transform infrared spectroscopy(FT-IR) and Ultraviolet-visible (UV–Vis) spectroscopy. The result of FESEM analysis showed that the polymer PVA, PAAm, and blend samples produced a random distribution of fine fibres at an average diameter of (214.12, 317.1, 157.65) nm with a smooth surface. In addition, the FESEM images demonstrate the fibres' suitability for use in gas sensing applications due to their branching fibres and porosity surface. XRD showed that the film polymeric of PVA, PAAm polymeric blend PVA-PAAm was seen to have a semicrystalline nature. According to the FTIR analysis, the PVA and PAAm networks in the PVA-PAAm polymer nanofibers were entangled due to the powerful hydrogen bond contact between the PAAm and PVA chains. Observed around (3473.79 and 3414) cm-1 were attributed to the N–H vibration and overlapped to O–H stretching. The spectra of the prepared films exhibit prominent absorption peaks, which are at the wavelength range (200-320) nm. PVA-PAAm polymer nanofibers decrease the energy gap from 3.70eV to 3.40eV. The Wemple-DiDomenico model was used to derive dispersion parameters such as dispersion energy, single oscillator energy, Urbach energy, the static refractive index and the moments of optical spectra the result of calculating by this model was compatible with that value calculated by the Tauc relation. While increased which qualifies them to be used in the electronic devices.

Null controllability of the advection-dispersion equation with respect to the dispersion parameter using the Fokas method

We investigate the null controllability of the linear advection-dispersion (LAD) equation posed on a finite interval. To this end, we employ the Fokas method to determine boundary controls and the controlled solutions concerning varying dispersion parameters and final times. By employing the Fokas method for the LAD equation, which provides an explicit integral representation of the solution, we enable a comprehensive analysis of null controllability. Consequently, we derive a boundary control input that effectively steers the solution from its initial state to the zero state within a given final time. The proposed approach offers a straightforward means to achieve the null controllability for the LAD equation, even as the dispersion parameter and the final time vary. Importantly, the effectiveness of this approach can be extended to various types of boundary control problems, thereby enhancing its broader applicability and potential impact.

Integer-Valued First Order Autoregressive (INAR(1)) Model With Negative Binomial (NB) Innovation For The Forecasting Of Time Series Count Data

This paper is about the theoretical investigation of integer-valued first order autoregressive (INAR(1)) model with negative binomial (NB) innovation for the forecasting of time series count data. The study makes use of the Conditional Least squares (CLS) estimator to estimate the parameter of INAR(1) model, and Maximum Likelihood Estimator (MLE) to estimate the mean (μ ) and the dispersion parameter (K) of the NB distribution. A simulation experiment based on theoretical generated data were addressed under different parameter values α =0.2, 0.6, 0.8, different sample sizes n=30, 90, 120, 600 for the class of INAR(1) model, and μ  =0.85, 1.5, 2,  K=1,2, 4 for the NB distribution. The Monte Carlo simulations were conducted with codes written in R, all results were based on 1000 runs. The estimation of parameter for the class of INAR(1) model gives a better result when the number of observations is small and the parameter value is high. The NB estimation gives a better result when the number of observations is small and with large K values. The forecasting accuracy of the model at different lead time period l =1, 3, 5, 7, 9, 15 were investigated with codes written in R. The results showed that the minimum mean square error (MMSE) produced when the number of lead times forecasts is between one and five were less than that produced when the numbers of lead times forecast were greater than five. The MMSE increased when the number of lead time periods increases. This result indicates that forecasting with this class of model is better with short time frame of predictions. The study was applied to the number of deaths arising from COVID-19 in Nigeria which consist of count time series data of 48 observations (weekly data), from January 2021 to December 2021.

Dynamic analysis of the effects of dissipative elements and modulational instability in a multicoupled nonlinear electrical transmission line with the propagation of new rogue waveforms

In this study, we consider a nonlinear multicoupled discrete electrical transmission line consisting of several modified Noguchi lines and analyze the dynamics of the effects of dissipative elements on modulated waves. This analysis shows that the dispersion element (C S ) and solution parameter (γ) strongly contribute to the increase in voltage amplitudes and to the modulation of these new rogue waveforms, unlike the dissipative element (G). Using a semi-discrete approximation, we demonstrate that the dynamics of modulated waves in such a dissipative electrical system can be governed by a system of nonlinear Schrödinger equations, the Manakov system, and system parameters. The phenomenon of modulational instability in this dissipative electrical system is studied, and areas of instability are shown. We found that the dissipative element of this system increased and decreased the areas of instability. Under the condition of this Manakov system, we determine the approximate modulated wave solutions that are then used for the dynamic analysis of the effects of dissipative elements when transmitting these new rogue waveforms through this dissipative electrical system. The effects of the parameters of this nonlinear dissipative electrical system, such as dispersive, dissipative, and solution parameters, in the dominant direction of propagation of these new rogue wave signals are presented. Based on these results, we observe that the effects of dissipative elements do exist in this nonlinear dissipative electrical system and that these dissipative elements would also impact the areas of modulational instability, which could gradually disappear in this electrical system.

TWO DIFFERENT METHODS COMPARATIVE ANALYSIS OF DETERMINING BODY DEFORMITIES IN STUDENTS

A research study was conducted on a sample of 110 male and female participants aged 11 and 12 years (±1.2 years) to compare two different methods for identifying spinal deformities. The aim was to determine which of the two methods is better and more applicable in practical school conditions. The methods compared were Napoleon Wolanski's method with 8 variables and the 3D method from Contemplas GmbH TEMPLO General Motion, assessed with a total of 11 variables. By analyzing the table of central dispersion parameters of body posture according to Napoleon Wolanski's method, the participants were classified into 5 groups based on the results. Participants with scores up to 8 points were considered to have good posture, while those with scores from 9 to 16 points were treated as having poor posture. The research revealed that a total of 66 out of 110 participants had poor posture, accounting for 60%. Results from the Contemplas method showed deviations from proper posture in almost all variables. The analysis indicated significant deviations in shoulder rotation, pelvic rotation, sagittal distances, and flexion/extension variables. Overall, the results demonstrated a high prevalence of body deformities in 11- and 12-year-old students. Analyzing the results of both methods for determining body deformities, it can be confidently stated that the frequency of body deformities in students aged 11 and 12 is significantly high. Napoleon Wolanski's method identified that 60% of participants had some form of spinal deformity, while the Contemplas method showed more pronounced results, with some variables indicating deformations in 80-85% of participants. Despite providing more detailed information about students' posture, the Contemplas method is less applicable in practical school conditions due to its significant cost. Therefore, Napoleon Wolanski's method remains indispensable in school settings.

Parameter estimation in the pollutant dispersion problem with Physics-Informed Neural Networks

In this work, the inverse problem of parameter estimation in the advection-dispersion-reaction equation, modelling the pollutant dispersion in a river, is studied with a Neural Network approach. In the direct problem, the dispersion, velocity and reaction parameters are known and then the initial and boundary value problem is solved by classical numerical methods, where it is used as input dataset for the inverse problem and formulation. In the inverse problem, we know the dispersion and the velocity parameters and also the information about the pollutant concentration from the synthetic experimental data, and then the aim is to estimate the reaction parameter in the advection-dispersion-reaction equation. This inverse problem is solved by an usual Artificial Neural Network (ANN) and by a Physics-Informed Neural Network (PINN), which is a special type of neural networks that includes in its formulation the physical laws that describe the phenomena involved. Numerical experiments with both the ANN and PINN are presented, demonstrating the feasibility of the approach considered.

Tailoring Optoelectronic Properties of ZnO Nanoparticles via Incorporation of Multiwalled Carbon Nanotube Contents on of ZnO/MWCNT Nanocomposites

The present study demonstrates the tailoring of optoelectronic properties of ZnO nanoparticles (NPs) by adding multi-walled carbon nanotubes (MWCNTs) at different weight ratios. ZnO/MWCNT nanocomposites were successfully prepared using the solution blending method, and the optical spectra of all samples were determined using a UV–vis spectrometer. An increase in the optical absorption coefficient (α) and extinction coefficient (k) was observed with an increase in MWCNT content, resulting in the significant ability to attenuate incident light in ZnO/MWCNT nanocomposites compared to pure ZnO NPs. The optical band gap of pure ZnO NPs decreased from 3.26 eV to 2.58 eV in the ZnO/50 wt% MWCNT nanocomposite. The refractive index values ranged from 1.66 to 1.61 as the wavelength varied between 400 nm and 700 nm. Furthermore, the incorporation of MWCNTs in the ZnO/MWCNT nanocomposite had an impact on various dispersion parameters related to the refractive index. With increasing MWCNT content, the dielectric constant (ε 0) decreased from 2.40 to 1.96, while the mean oscillator wavelength (λ 0) increased from 157.7 nm to 164.2 nm and the oscillator strength (S0) decreased from 5.93 × 10−5 nm−2 to 3.70 × 10−6 nm−2. The localized density of state (N/m*) increased from 7.45 × 1057 to 20.8 × 1057 (m3 Kg) −1, and the long wavelength refractive index (ε ∞) rose from 3.683 to 4.745. Moreover, the plasma frequency (ω p) of the electron exhibited an increase from 2.15 × 1031 to 6.01 × 1031 Hz. These findings highlight the potential of tailoring the optoelectronic properties of ZnO NPs through the incorporation of MWCNTs, paving the way for the development of novel materials with improved optoelectronic characteristics for a wide range of applications.