Miracle-dz/UniFAR-FTUs huggingface dataset:
Students’ Understanding of the Mean Through Technology-Mediated Analysis of Real-Life Data

This study conducts cognitive research in digital environments to bridge students’ understanding of the mean and the use of technology for data analysis. By activating definitions, properties, arguments, representations, and algorithms of the mean, this study approaches the questions: (1) How does using Microsoft Excel affect the configuration of students’ meaning of the mean? (2) What semiotic conflicts are associated with using Microsoft Excel and a real dataset? We applied an open-ended questionnaire to 17 engineering students taking the introductory Probability and Statistics course that integrates Microsoft Excel as a didactic strategy. The data collection used convenience sampling with the students enrolled in the fall of 2022. We found that technology for data analysis is more than a complementary tool for students because it allows them to express their reasoning through virtual representations. The analysis yielded new semiotic conflicts in students’ calculation of the mean. The data suggests that the tendency to make calculation errors increases when data analysis involves raw data extracted from real life.
Recent advances in fundamentals and applications of random fiber lasers

Random fiber lasers blend together attractive features of traditional random lasers, such as low cost and simplicity of fabrication, with high-performance characteristics of conventional fiber lasers, such as good directionality and high efficiency. Low coherence of random lasers is important for speckle-free imaging applications. The random fiber laser with distributed feedback proposed in 2010 led to a quickly developing class of light sources that utilize inherent optical fiber disorder in the form of the Rayleigh scattering and distributed Raman gain. The random fiber laser is an interesting and practically important example of a photonic device based on exploitation of optical medium disorder. We provide an overview of recent advances in this field, including high-power and high-efficiency generation, spectral and statistical properties of random fiber lasers, nonlinear kinetic theory of such systems, and emerging applications in telecommunications and distributed sensing.
Work in Progress: Mflow, a Flow-based Music Programming Platform for Young Children

Students of all socioeconomic backgrounds love music and express their identity through music. There are strong historical connections between music and computing, and computer-based music has a heavy presence in contemporary popular culture. Thus, programming electronic music can provide the type of authentic learning experience that fosters participation in computer science (CS) by minoritized students. Although important efforts have been made in that direction, they have not reached young children in mainstream public classrooms, particularly in schools serving children from low-income and marginalized backgrounds. Developing a computational tool and educational program that reaches this key demographic holds the potential to greatly increase CS knowledge and participation in the future workforce. For this, our team has created M-flow, a flow-based music programming platform that seeks to be engaging for children from the outset, and that makes it extremely easy for non-specialized teachers to learn and implement CS activities in the classroom.
Viscous fluid instabilities under an elastic sheet

This thesis considers the flow of thin fluid film between an elastic sheet and a rigid plane. We derive a mathematical model for the flow from the NavierStokes equations using the lubrication approximation and develop numerical and similarity solutions to this problem. An experimental apparatus was developed to investigate this phenomenon, and the results of the mathematical model were compared with experimental data. Chapter 3 examines the evolution of a fixed fluid volume under gravitational forces on a horizontal plane. The evolution of the fluid mass profile and the progression of the fluid front are determined from the numerical solutions, as well as experimentally. The favourable comparison between the numerical solutions and the experimental results establishes the validity of the model. Chapters 4-5 considers the evolution of a thin fluid flow under an elastic on an inclined plane. We establish a traveling wave solution for this flow. A linear stability analysis yields the criterion for the existence of unstable modes and establishes the growth rate and wavelength of the most unstable mode. Instability is promoted by increasing the inclination of the plane. For low angles, the numerical and experimental growth rates were in good agreement, while the wavelengths were experimentally of the same order and numerically computed wavelengths had little variation. The long term behaviour of the fluid front is studied analytically via a similarity solution in Chapter 6.
Analysis of University Engineering Program Skill Effectiveness in Research & Development Companies

The current study focused on recent bachelor of science graduates' perceptions of the usefulness of the abilities they acquired throughout their undergraduate studies while working for research and development firms. A literature review was used to create a survey. Using government reports, a sample frame of 1600 businesses was chosen to reflect the target group of employers in the U.S.'s research and development sector. N=366 bachelor's degree in science students who started working on or after June 1, 2022 were surveyed to gather data. To lessen respondent bias or lying in the survey, a fresh statistical research element was incorporated. The hypotheses were tested using correlation and descriptive statistics. The dependent variables of program learning effectiveness, employment skill match, and program return on investment were all strongly correlated with all R&D skill characteristics.
Performances of PRIME PLC-RF Hybrid Communication Systems

This paper reviews the main changes in the new version of the PRIME standard, especially its evolution towards a hybrid system combining Power Line Communications (PLC) and Radio Frequency (RF). In particular, the current simulation results are presented by comparing the system performance in three Advanced Metering Infrastructure (AMI) use cases with each other and with the results of a previous work analyzing the new version of the G3 standard. The first case is an environment where all nodes are PLC and the PLC noise level allows connectivity in all areas of the site. The second case is an environment where all nodes are PLC+RF, the PLC noise level does not allow connectivity in some areas, and the system needs to switch to RF. The third case is an environment where half of the nodes are PLC+RF and the others half are RF only. This would be the situation of a system with electricity meters, which are hybrid PLC+RF, and gas or water meters, which are RF only. To evaluate their performance, some Key Performance Indicators suitable for these applications are introduced.
Sequential Channel Synthesis

The channel synthesis problem has been widely investigated over the last decade. In this paper, we consider the sequential version in which the encoder and the decoder work in a sequential way. Under a mild assumption on the target joint distribution we provide a complete (single-letter) characterization of the solution for the point-to-point case, which shows that the canonical symbol-by-symbol mapping is not optimal in general, but is indeed optimal if we make some additional assumptions on the encoder and decoder. We also extend this result to the broadcast scenario and the interactive communication scenario. We provide bounds in the broadcast setting and a complete characterization of the solution under a mild condition on the target joint distribution in the interactive communication case. Our proofs are based on a Rényi entropy method.
Finite-time stability for continuous-time switched systems in the presence of impulse effects

The problem of finite-time stability for a class of continuous-time switched systems with impulse effects is studied in this article. A criterion is proposed which ensures that the system’s state trajectory remains in a bounded region of the state space over a pre-specified finite-time interval if the authors give a bound on the initial condition. Contrary to the existing results on finite-time stability of switched systems, the average dwell time approach, rather than the Lyapunov-based ones, is utilised to realise such a purpose. The difference between the finite-time stability and the Lyapunov stability is clearly shown. A numerical example is given to illustrate the proposed design method.
On Hidden Symmetries of d>4 NHEK-N-AdS Geometry

As well known, all higher dimensional Kerr-NUT-Ads metrics with arbitrary rotation and NUT parameters in an asymptotically AdS spacetime have a new hidden symmetry. In this paper, we show that in the near horizon, the isometry group is enhanced to include the dilatation and special conformal transformation, and find the conformal transformation contains the cosmological constant. It is demonstrated that for near horizon extremal Kerr-NUT-Ads (NHEK-N-AdS) only one rank-2 Killing tensor decomposes into a quadratic combination of the Killing vectors in terms of conformal group, while the others are functionally independent.
Radio measurements of the energy and depth of maximum of cosmic-ray air showers by Tunka-Rex

Radio measurements of the energy and depth of maximum of cosmic-ray air showers by Tunka-Rex P.A. Bezyazeekov N.M. Budnev O.A. Gress A. Haungs R. Hiller T. Huege Y. Kazarina M. Kleifges E.N. Konstantinov E.E. Korosteleva D. Kostunin O. Kromer L.A. Kuzmichev N. Lubsandorzhiev R.R. Mirgazov R. Monkhoev A. Pakhorukov L. Pankov V.V. Prosin G.I. Rubtsov F.G. Schroder, R. Wischnewski A. Zagorodnikov Tunka-Rex Collaboration Institute of Applied Physics ISU, Irkutsk, Russia Institut fur Kernphysik, Karlsruhe Institute of Technology (KIT), Germany Institut fur Prozessdatenverarbeitung und Elektronik, Karlsruhe Institute of Technology (KIT), Germany Skobeltsyn Institute of Nuclear Physics MSU, Moscow, Russia Institute for Nuclear Research of the Russian Academy of Sciences, Moscow, Russia DESY, Zeuthen, Germany
Scoping Review of Early Toxic Stress and Epigenetic Alterations in the Neonatal Intensive Care Unit

Background Preterm infants are uniquely vulnerable to early toxic stress exposure while in the neonatal intensive care unit (NICU) and also being at risk for suboptimal neurodevelopmental outcomes. However, the complex biological mechanisms responsible for variations in preterm infants’ neurodevelopmental outcomes because of early toxic stress exposure in the NICU remain unknown. Innovative preterm behavioral epigenetics research offers a possible mechanism and describes how early toxic stress exposure may lead to epigenetic alterations, potentially affecting short- and long-term outcomes. Objective The aim of this study was to review the relationships between early toxic stress exposures in the NICU and epigenetic alterations in preterm infants. The measurement of early toxic stress exposure in the NICU and effect of epigenetic alterations on neurodevelopmental outcomes in preterm infants were also examined. Methods We conducted a scoping review of the literature published between January 2011 and December 2021 using databases PubMed, CINAHL, Cochrance Library, PsycINFO, and Web of Science. Primary data-based research that examined epigenetics, stress, and preterm infants or NICU were included. Results A total of 13 articles from nine studies were included. DNA methylations of six specific genes were studied in relation to early toxic stress exposure in the NICU: SLC6A4, SLC6A3, OPRMI, NR3C1, HSD11B2, and PLAGL1. These genes are responsible for regulating serotonin, dopamine, and cortisol. Poorer neurodevelopmental outcomes were associated with alterations in DNA methylation of SLC6A4, NR3C1, and HSD11B2. Measurements of early toxic stress exposure in the NICU were inconsistent among the studies. Discussion Epigenetic alterations secondary to early toxic stress exposures in the NICU may be associated with future neurodevelopmental outcomes in preterm infants. Common data elements of toxic stress exposure in preterm infants are needed. Identification of the epigenome and mechanisms by which early toxic stress exposure leads to epigenetic alterations in this vulnerable population will provide evidence to design and test individualized intervention.
Gradient blowup rate for a heat equation with general gradient nonlinearity

This paper is focused on the gradient blowup rate for the following general semilinear parabolic equation with being a smoothly bounded domain in and being a smooth function. Under some suitable assumptions on , we establish the gradient blowup rate lower bound by the rescaling method for any . While the upper bound which is established by the comparison method can be obtained only for . At last, we provide some specific examples to verify our results.
Numerical Modeling of the Mixing of Highly Viscous Polymer Suspensions in Partially Filled Sigma Blade Mixers

This paper presents a non-isothermal, non-Newtonian Computational Fluid Dynamics (CFD) model for the mixing of a highly viscous polymer suspension in a partially filled sigma blade mixer. The model accounts for viscous heating and the free surface of the suspension. The rheological model is found by calibration with experimental temperature measurements. Subsequently, the model is exploited to study the effect of applying heat both before and during mixing on the suspension’s mixing quality. Two mixing indexes are used to evaluate the mixing condition, namely, the Ica Manas-Zlaczower dispersive index and Kramer’s distributive index. Some fluctuations are observed in the predictions of the dispersive mixing index, which could be associated with the free surface of the suspension, thus indicating that this index might not be ideal for partially filled mixers. The Kramer index results are stable and indicate that the particles in the suspension can be well distributed. Interestingly, the results highlight that the speed at which the suspension becomes well distributed is almost independent of applying heat both before and during the process.
Chaos and synchronization of self-pulsating laser diodes

It is shown theoretically that synchronization between two chaotic self-pulsating laser diodes can be achieved by use of optical feedback levels of a few percent. The sensitivity of the synchronization to parameter changes is examined. A synchronization scheme that utilizes self-pulsating compact disc laser diodes could produce low-cost stand-alone transmitters and receivers for private communication systems.
Novel formulations of the boundary element method for fracture mechanics and error estimation

A unified approach for boundary integral equations is presented and used in the development of subsequent formulations for fracture mechanics and error estimation. With respect to fracture mechanics, it is shown that the linear terms in the near crack-tip displacement expansions, on both sides of a crack, are equal. The general derivation of this constraint equation is based on a hypersingular integral formulation for two-dimensional linear elastic fracture mechanics. This result is also validated by the eigenfunction expansion method. Inclusion of this constraint in numerical calculations should result in a better approximation of the displacement and stress fields in the near tip region, and thus a more accurate numerical evaluation of stress intensity factors. Moreover, by evaluating an appropriate limit of the hypersingular boundary integral equation for stresses, formulae for stress intensity factors are obtained. Next, two new approaches for a posteriori error estimation are developed. First, a pointwise boundary error estimator for the boundary element method, which also relies upon the evaluation of hypersingular integrals, is presented. A methodology is developed for approximating the error on the boundary as well as in the interior of the domain. Extensive computational experiments have been performed for potential problems, and the numerical results indicate that the error estimates successfully track the form of the exact error curve. Moreover, a reasonable estimate of the magnitude of the actual error is also predicted. Second, a general method for error estimation in computational mechanics is developed. It consists of using special sensitivities, called nodal sensitivities, as error estimates. Although this idea is applicable to various numerical methods, the theory has been developed in detail for the boundary element method. Implementation has been carried out for elasticity problems, and the numerical results compare well with available analytical solutions.
The role of artificial intelligence in integrated marketing communications: A case study of Jumia Online Ghana

Artificial intelligence (AI) has been observed as both a destructive and a transformative game changer in all human activities where it has been adopted. This study looked into the role of Artificial Intelligence in Integrated Marketing Communications, with Jumia Online Ghana as a case. Through the use of both quantitative and qualitative approaches, as well as convenience and purposive sampling techniques, the study obtained qualitative and quantitative data from IT staff and customers of Jumia Online Ghana. A total of 112 respondents participated in the study. The study revealed that Jumia Online Ghana boost their marketing communications; undertake marketing leads; and promote their contents and products through the use of Artificial Intelligence. The study recommends that the need exists for AIpowered contents of Jumia Online Ghana to be optimized for mobile devices. It has been established that the use of AI empowers marketing communications in order to reach wider markets.
Infinite-Dimensional Monoids Constructed from Kac-Moody Groups

We construct an infinite dimensional monoid from a Kac-Moody group and an irreducible highest weight representation of the group over the complex number field $\C$. The unit group $G$ of the monoid is the product of the multiplicative group $\C^\times$ and the homomorphic image of the Kac-Moody group under the representation. The idempotents of the monoid, which are intimately connected to the group structure, are determined by the face lattice of the convex hull $H$ of the weight set of the representation. We further establish the Bruhat decomposition for this monoid. The index set of the decomposition is a certain infinite inverse monoid whose unit group is the Weyl group of the Kac-Moody group. Furthermore, we obtain an infinite dimensional monoid version of the Tits System, and we find that the Borel subgroups of $G$ are closely related to the monoid structure in terms of a cross-section lattice defined from fundamental faces of $H$. This leads to the decomposition of the monoid into orbits of the two-sided action of $G$ on the monoid. Moreover, the monoid is unit regular. We describe the parabolic subgroups of $G$ using left and right centralizers of idempotents, and introduce the type map of the monoid. We also provide a method to construct the cross-section lattice using those subsets of the Dynkin diagram that are connected through the highest weight of the representation.
Sensory Motor Function Disturbances in Mice Prenatally Exposed to Low Dose of Ethanol: A Neurobehavioral Study in Postnatal and Adult Stages

Prenatal alcohol exposure (PAE) refers to fetal exposure to alcohol during pregnancy through placental barrier transfer from maternal blood. The postnatal outcomes of PAE differ among exposed individuals and range from overt (serious) alcohol-related behavioral and neurophysiological impairments to covert (silenced) symptoms. The aims of the present investigation were to assess the postnatal neurobehavioral disturbances, particularly, motor coordination and sensory-motor function in mice with PAE. Female mice with positive vaginal plugs were divided into three groups: group 1: Et + Pyr: received two i.p injections of ethanol (1 g/kg) followed by pyrazole (100 mg/kg). Group 2: Pyr: received an i.p injection of pyrazole (100 mg/kg). Group 3: C: of saline controls received, in equal volume, saline solution (NaCl 0.9%). After birth, mice pups were weighed and subjected to behavioral tests for motor function screening using the motor ambulation test, cliff aversion, surface righting, and negative geotaxis, while at the adult stage, mice were subjected to the open field, rotarod, parallel bars, and static rods tests. Our data show an obvious decrement of body weight from the first post-natal day (P1) and continues over the adult stage. This was accompanied by an obvious impaired sensory-motor function which was maintained even at the adult stage with alteration of the locomotor and coordination abilities. The current data demonstrate the powerful neurotoxic effect of prenatal ethanol exposure on the sensory-motor and coordination functions, leading to suppose possible structural and/or functional neuronal disturbances, particularly the locomotor network.
Sharp inequalities for solutions of multipoint boundary value problems

This paper considers the following continuous and discrete multipoint boundary value problems: x(n)(t) 0, 0 t 1, x(ti) = 0 and Δny(k) 0, k = 0, · · · , m, Δy(ki) = 0, where j = 0, · · · , ni − 1, i = 1, · · · , r, ∑r i=1 ni = n, 0 = t1 < t2 < · · · < tr = 1, and 0 = k1 < k1 + n1 < k2 < k2 + n2 < · · · < kr kr + nr − 1 = m + n. We offer lower bounds for solutions of these boundary value problems in terms of sup0 t 1 |x(t)| and maxk∈{0,··· ,m+n} |y(k)|. These bounds further lead to inequalities for related Green’s functions which are very useful in the study of positive solutions of boundary value problems. Mathematics subject classification (1991): 34A40, 39A10.
Public debt and economic growth nexus in sub-saharan Africa: does institutional quality matter?

ABSTRACT This paper investigates the effect of institutional quality and public debt on economic growth among sub-Saharan African countries. The study employs the System Generalized Method of Moments (SGMM) and the Fixed Effect techniques on data from 35 Sub Saharan African countries (sourced from the World Development Indicators (WDI) and the World Governance Index (WGI) databases from 2010 to 2020). The results reveal that institutional quality has a significantly negative effect on public debt; public debt has a significantly negative effect on economic growth; and institutional quality has a significantly positive effect on economic growth. This suggests that countries with weak institutions may have debt overhang deleterious to economic growth.