Miracle-dz/UniFAR-FTUs huggingface dataset:
Learning, digital technologies, and sociomaterial approaches: A critical reflection from the perspective of materialist dialectics

In this article, I attempt to critically reflect on sociomaterial approaches to learning, especially as it is conducted with digital technologies. By pursuing detailed ethnographic case studies, these approaches argue for the active character of digital technologies in the constitution of learning. More specifically, digital technologies are treated in this paradigm as co-participants—along with humans—in the formation of learning practices. Despite their invaluable empirical insights, I suggest that these approaches do not adequately emphasize the transformative potential of learners and do not conceptualize learning from the perspective of human development. In addition, I propose that, apart from empirically based research, which is the preferred mode of research of sociomaterial approaches, there is also a need for categorical thinking to conceptualize the mediation of learning by digital technologies. In my critical reflection, I draw on scholars working in the traditions of cultural-historical theory and activity theory, and on materialist dialectics more generally
Cycle symmetries and circulation fluctuations for discrete-time and continuous-time Markov chains

In probability theory, equalities are much less than inequalities. In this paper, we find a series of equalities which characterize the symmetry of the forming times of a family of similar cycles for discrete-time and continuous-time Markov chains. Moreover, we use these cycle symmetries to study the circulation fluctuations for Markov chains. We prove that the empirical circulations of a family of cycles passing through a common state satisfy a large deviation principle with a rate function which has an highly non-obvious symmetry. Finally, we discuss the applications of our work in statistical physics and biochemistry.
Evidence for B+ -> tau+ nu_tau decays using hadronic B tags

We present a search for the decay B+ --> tau+ nu_tau using 467.8 x 10^6 B B-bar pairs collected at the Upsilon(4S) resonance with the BABAR detector at the SLAC PEP-II B-Factory. We select a sample of events with one completely reconstructed B- in an hadronic decay mode (B- --> D{(*)0}X- and B- --> J/psi X-). We examine the rest of the event to search for a B+ --> tau+ nu_tau decay. We identify the tau+ lepton in the following modes: tau+ --> e+ nu nu, tau+ --> mu+ nu nu, tau+ --> pi+ nu and tau+ --> rho nu. We find an excess of events with respect to expected background, which excludes the null signal hypothesis at the level of 3.3 sigma and can be converted to a branching fraction central value of B( B+ --> tau+ nu_tau )=( 1.80 +0.57 -0.54 (stat.) +-0.26 (syst.)) x 10^{-4}.
Analyzing spatial data: An assessment of assumptions, new methods, and uncertainty using soil hydraulic data

Environmental scientists today enjoy an ever‐increasing array of geostatistical methods to analyze spatial data. Our objective was to evaluate several of these recent developments in terms of their applicability to real‐world data sets of the soil field‐saturated hydraulic conductivity (Ks). The intended synthesis comprises exploratory data analyses to check for Gaussian data distribution and stationarity; evaluation of robust variogram estimation requirements; estimation of the covariance parameters by least‐squares procedures and (restricted) maximum likelihood; use of the Matérn correlation function. We furthermore discuss the spatial prediction uncertainty resulting from the different methods. The log‐transformed data showed Gaussian uni‐ and bivariate distributions, and pronounced trends. Robust estimation techniques were not required, and anisotropic variation was not evident. Restricted maximum likelihood estimation versus the method‐of‐moments variogram of the residuals accounted for considerable differences in covariance parameters, whereas the Matérn and standard models gave very similar results. In the framework of spatial prediction, the parameter differences were mainly reflected in the spatial connectivity of the Ks field. Ignoring the trend component and an arbitrary use of robust estimators would have the most severe consequences in this respect. Our results highlight the superior importance of a thorough exploratory data analysis and proper variogram modeling, and prompt us to encourage restricted maximum likelihood estimation, which is accurate in estimating fixed and random effects.
The Relationship Between Perceived Social Support and Medication Adherence Among Adult Type 2 Diabetes Mellitus Patients Attending the Diabetes Clinic in a Tertiary Health Institution in South- South Nigeria

Purpose: Medication adherence can be defined as the extent to which a patient’s behaviour corresponds to the medication dosing regimen including time, dosing, and interval of medication intake. In chronic conditions with long-term therapies like hypertension, diabetes, depression, etc., adherence is important in achieving target outcomes but is often low. It has long been recognized that support from family, friends and significant others do play a role in helping diabetics adhere to their medication which might lead to optimal glycaemic control. This study set out to find out what influence perceived social support has, as regards medication adherence among adult type 2 diabetic Nigerians assessing care in Federal Medical Centre, Asaba, Nigeria. Methodology: The study was conducted on 244 participants who attended the diabetic clinic of the Federal Medical Centre, Asaba from September to November 2018. Data was collected by means of an interviewer-administered questionnaire comprising of 3 sections. Section A was for sociodemographic characteristics, section B was the 8-item Morisky Medication Adherence Scale for information on medication adherence and section C was the modified Multidimensional Scale of Perceived Social Support to collect information on perceived social support. Findings: All the recruited 244 participants completed the study giving a response rate of 100. The age range of the respondents was 18 to 87 years with a mean age of 51.9 ± 6.1 years. Females accounted for a higher percentage of respondents [60.2%] compared to their male counterparts [39.8%]. Good total perceived social support was significantly associated with high medication adherence [p=0.0001]. A good total perceived social support (OR = 3.27; 95% CI = 2.25 - 4.71; P = 0.0001) has 3.27 times the odds for high medication adherence than a poor total perceived social support. Unique Contribution to Theory, Policy and Practice: The study shows that high medication adherence is significantly associated with good perceived social support. It is important that healthcare providers caring for patients with type 2 diabetes involve families, friends, or significant others in their management so as to improve their medication adherence. Routine evaluation of perceived social support is also recommended for type 2 diabetes patients with poor medication adherence.
Lie group and exponential integrators: Theory, implementation, and applications

This PhD-thesis contains an introduction and six research papers sorted chronologically, of which the first four are accepted for publication. The introduction aims at giving a very brief summary of the background theory needed for the following papers. Also, some motivation of the issues addressed by the papers is given. Paper I discusses algebraic structures of ordered rooted trees and their applications to Lie group integrators. Results from Hopf algebra theory on elementary differentials for Lie group integrators are used, and applications to order analysis and backward error analysis are given. Paper II, III, IV, and V are primarily on exponential integrators, a class of numerical schemes tailored the solution of stiff systems of systems of ordinary differential equations. Paper II discusses classical order analysis and gives some theoretical results on the form of the integrators, applicable for the construction of high order exponential integrators. Paper III is on an implementation of exponential integrators on computers, and source code, available electronically, accompanies the paper. Paper IV includes an analytical and numerical study of the performance of two classes of exponential integrators on the nonlinear Schrodinger equation. Paper V is a numerical study of behaviour over long integration invervals on the nonlinear Schrodinger equation, using nonlinear spectral theory for determining validity of the numerical solution and thereby jugdging the numerical integrators. At last, in Paper VI, properties of a class of exponential like functions, essential in exponential integrators, are derived, using an approach based on Lie group theory.
Observation and Analysis of Anomalous VTH Shift of p-GaN Gate HEMTs Under off-State Drain Stress

In this work, time-dependent threshold voltage (<inline-formula> <tex-math notation="LaTeX">${V}_{\text {TH}}$ </tex-math></inline-formula>) instability of p-GaN gate high electron mobility transistors (HEMTs) under OFF-state drain stress is systematically investigated. An anomalous <inline-formula> <tex-math notation="LaTeX">${V}_{\text {TH}}$ </tex-math></inline-formula> shift behavior is observed with an initial negative shift followed by a kink and a positive shift upon prolonged stress time. Through bias- and temperature-dependent stress/recovery experiments, it has been found that the process of electron releasing by donor states at the p-GaN/AlGaN and AlGaN/GaN interface is the primary reason for negative <inline-formula> <tex-math notation="LaTeX">${V}_{\text {TH}}$ </tex-math></inline-formula> shift in the initial stage. The hole deficiency in the p-GaN layer gradually dominates the change in <inline-formula> <tex-math notation="LaTeX">${V}_{\text {TH}}$ </tex-math></inline-formula> and finally leads to a positive <inline-formula> <tex-math notation="LaTeX">${V}_{\text {TH}}$ </tex-math></inline-formula> shift. Moreover, a continual leakage path between the gate and drain terminal during the stress stage is further revealed which is mainly ascribed to the trap-assisted electron tunneling across the AlGaN layer. In addition, the effect of OFF-state drain stress on static ON-resistance (<inline-formula> <tex-math notation="LaTeX">${R}_{\text{ON}}$ </tex-math></inline-formula>) is also studied, and it is found that the trapped electrons at the passivation/AlGaN interface and/or in the GaN buffer layer results in the <inline-formula> <tex-math notation="LaTeX">${R}_{\text{ON}}$ </tex-math></inline-formula> degradation.
Dispersive spin excitations in highly overdoped cuprates revealed by resonant inelastic x-ray scattering

Using resonant inelastic x-ray scattering (RIXS) at the Cu $L$-absorption edge, we have observed intense, dispersive spin excitations in highly overdoped Tl$_2$Ba$_2$CuO$_{6+\delta}$ (superconducting $T_c =6$ K), a compound whose normal-state charge transport and thermodynamic properties have been studied extensively and shown to exhibit canonical Fermi-liquid behavior. Complementary RIXS experiments on slightly overdoped Tl$_2$Ba$_2$CuO$_{6+\delta}$ ($T_c =89$ K) and on Y$_{1-x}$Ca$_{x}$Ba$_2$Cu$_3$O$_{6+\delta}$ compounds spanning a wide range of doping levels indicate that these excitations exhibit energies and energy-integrated spectral weights closely similar to those of antiferromagnetic magnons in undoped cuprates. The surprising coexistence of Fermi-liquid-like charge excitations and high-energy spin excitations reminiscent of antiferromagnetic insulators in highly overdoped compounds poses a challenge to current theoretical models of the cuprates.
Acute Toxicity of Household-Scale Lebak Batik Industrial Wastewater on Common Carp

The concentration of Lebak Batik industrial wastewater contains the pollutant element of lead metal that negatively impacts organisms' content in the water. This study was focused on the acute toxicity of household-scale Lebak Batik industrial wastewater on carp. The methods used were waste characteristics test, animal acclimatization, acute toxicity test for 96 hours with 0, 10, 20, 30, 40, and 50% treatments, measurement of environmental parameters, and data analysis using probit analysis. The results showed that the lethal time (LT50) and lethal concentration (LC50) for 96 hours of treatment were 1,8 days and 8,56%, respectively, with a Toxicity Unit Area (TUa) of 11,68. This proved that the wastewater from the Lebak batik industry had a major effect on causing acute toxicity.
MAGNETIC STRUCTURE AND DYNAMICS OF THE ERUPTING SOLAR POLAR CROWN PROMINENCE ON 2012 MARCH 12

We present an investigation of the polar crown prominence that erupted on 2012 March 12. This prominence is observed at the southeast limb by the Solar Dynamics Observatory (SDO)/Atmospheric Imaging Assembly (AIA; end-on view) and displays a quasi-vertical thread structure. A bright U-shaped or horn-like structure is observed surrounding the upper portion of the prominence at 171 Å before the eruption and becomes more prominent during the eruption. The disk view of STEREO _ B ? > shows that this long prominence is composed of a series of vertical threads and displays a half-loop-like structure during the eruption. We focus on the magnetic support of the prominence vertical threads by studying the structure and dynamics of the prominence before and during the eruption using observations from SDO and STEREO_B. We also construct a series of magnetic field models (sheared arcade model, twisted flux rope model, and unstable model with hyperbolic flux tube). Various observational characteristics appear to be in favor of the twisted flux rope model. We find that the flux rope supporting the prominence enters the regime of torus instability at the onset of the fast-rise phase, and signatures of reconnection (posteruption arcade, new U-shaped structure, rising blobs) appear about one hour later. During the eruption, AIA observes dark ribbons seen in absorption at 171 Å corresponding to the bright ribbons shown at 304 Å, which might be caused by the erupting filament material falling back along the newly reconfigured magnetic fields. Brightenings at the inner edge of the erupting prominence arcade are also observed in all AIA EUV channels, which might be caused by the heating due to energy released from reconnection below the rising prominence.
THE INTERPLAY OF MAGNETIC FIELDS, FRAGMENTATION, AND IONIZATION FEEDBACK IN HIGH-MASS STAR FORMATION

Massive stars disproportionately influence their surroundings. How they form has only started to become clear recently through radiation gas dynamical simulations. However, until now, no simulation has simultaneously included both magnetic fields and ionizing radiation. Here we present the results from the first radiation-magnetohydrodynamical (RMHD) simulation including ionization feedback, comparing an RMHD model of a 1000 M☉ rotating cloud to earlier radiation gas dynamical models with the same initial density and velocity distributions. We find that, despite starting with a strongly supercritical mass-to-flux ratio, the magnetic field has three effects. First, the field offers locally support against gravitational collapse in the accretion flow, substantially reducing the amount of secondary fragmentation in comparison to the gas dynamical case. Second, the field drains angular momentum from the collapsing gas, further increasing the amount of material available for accretion by the central, massive, protostar, and thus increasing its final mass by about 50% from the purely gas dynamical case. Third, the field is wound up by the rotation of the flow, driving a tower flow. However, this flow never achieves the strength seen in low-mass star formation simulations for two reasons: gravitational fragmentation disrupts the circular flow in the central regions where the protostars form, and the expanding H ii regions tend to further disrupt the field geometry. Therefore, ionizing radiation is likely to dominate outflow dynamics in regions of massive star formation.
Quantitative equidistribution properties of toral eigenfunctions

We prove quantitative equidistribution properties for orthonormal bases of eigenfunctions of the Laplacian on the rational $d$-torus. We show that the rate of equidistribution of such eigenfunctions is of polynomial decay. We also prove that equidistribution of eigenfunctions holds for symbols supported in balls with a radius shrinking at a polynomial rate.
AGN host galaxies at redshift z 0.7: peculiar or not?

Aims. We perform a quantitative morphological comparison between the hosts of active galactic nuclei (AGN) and quiescent galaxies at intermediate redshifts (z ≈ 0.7). The imaging data are taken from the large HST/ACS mosaics of the GEMS and STAGES surveys. Our main aim is to test whether nuclear activity at this cosmic epoch is triggered by major mergers. Methods. Using images of quiescent galaxies and stars, we created synthetic AGN images to investigate the impact of an optical nucleus on the morphological analysis of AGN hosts. Galaxy morphologies are parameterized using the asymmetry index A ,t he concentration index C, the Gini coefficient G ,a nd theM20 index. A sample of ∼200 synthetic AGN was matched to 21 real AGN in terms of redshift, host brightness, and host-to-nucleus ratio to ensure a reliable comparison between active and quiescent galaxies. Results. The optical nuclei strongly affect the morphological parameters of the underlying host galaxy. Taking these effects into account, we find that the morphologies of the AGN hosts are clearly distinct from galaxies undergoing violent gravitational interactions. Indeed, the host galaxy distributions in morphological descriptor space are more similar to undisturbed galaxies than to major mergers. Conclusions. Intermediate-luminosity (LX < 10 44 erg/s) AGN hosts at z ≈ 0.7 show morphologies similar to the general population of massive galaxies with significant bulges at the same redshifts. If major mergers are the driver of nuclear activity at this epoch, the signatures of gravitational interactions fade rapidly before the optical AGN phase starts, making them undetectable on single-orbit HST images, at least with usual morphological descriptors. This could be investigated in future synthetic observations created from numerical simulations of galaxy-galaxy interactions.
Conformal Differential Geometry and Its Generalizations

Conformal and Pseudoconformal Spaces. Hypersurfaces in Conformal Spaces. Submanifolds in Conformal and Pseudoconformal Spaces. Conformal Structures on a Differentiable Manifold. The Four--Dimensional Conformal Structures. Geometry of the Grassmann Manifold. Manifolds Endowed with Almost Grassmann Structures. Bibliography. Symbols Frequently Used. Indexes.
Discovery of a high-z protocluster with tunable filters: the case of 6C0140+326 at z=4.4

We present the first results obtained using a tunable narrow-band filter in the search for high-z protoclusters. Using the recently commissioned red tunable filter on the Gran Telescopio Canarias, we have searched for Lyα emitters in a 75 arcmin2 field centred on the z= 4.413 radio galaxy 6C0140+326. With three different wavelength tunings, we find a total of 27 unique candidate Lyα emitters. The availability of three different wavelength tunings allows us to make estimates of the redshifts for each of the objects. It also allows us to separate a possible protocluster from a structure in the immediate foreground. This division shows that the foreground region contains significantly fewer Lyα emitters. Also, the spatial distribution of the objects in the protocluster field deviates from a random distribution at the 2. 5σ level. The observed redshift distribution of the emitters is different from the expected distribution of a blank field at the ∼3σ level, with the Lyα emitters concentrated near the radio galaxy at z > 4.38. The 6C0140+326 field is denser by a factor of 9 ± 5 than a blank field, and the number density of Lyα emitters close to the radio galaxy is similar to that of the z∼ 4.1 protocluster around TN J1338−1942. We thus conclude that there is an overdensity of Lyα emitters around the radio galaxy 6C0140+326. This is one of few known overdensities at such a high redshift.
KK 246: A DWARF GALAXY WITH AN EXTENDED H i DISK IN THE LOCAL VOID

We have found that KK 246, the only confirmed galaxy located within the nearby Tully Void, is a dwarf galaxy with an extremely extended H i disk and signs of an H i cloud with anomalous velocity. It also exhibits clear misalignment between the kinematical major and minor axes, indicative of an oval distortion, and a general misalignment between the H i and optical major axes. We measure an H i mass of (1.05 ± 0.08) × 108 M☉, and an H i extent five times that of the stellar disk, one of the most extended H i disks known. We estimate a dynamical mass of 4.1 × 109 M☉, making this also one of the darkest galaxies known, with a mass-to-light ratio of 89. The relative isolation and extreme underdense environment make this an interesting case for examining the role of gas accretion in galaxy evolution.
Parameter estimation in atomic spectroscopy using exceptional points

The dynamics of spontaneous emission of an atomic system is studied in the framework of an open quantum system. The resulting quantum master equation for the atomic system is non hermitian. The generator $\mathcal{L}$ can possess non-hermitian degeneracies, i.e. exceptional points ($EP$), for specific values of the external laser driving amplitude and detuning from the atomic lines. We suggest to employ the special properties of these $EP$s for accurate parameter estimation. The method is demonstrated for the atomic spectrum of $S \rightarrow P$ transitions of $~^{85}$Rb and $~^{40}$Ca$~^+$.
THE DISTRIBUTION OF ALPHA ELEMENTS IN ULTRA-FAINT DWARF GALAXIES

The Milky Way ultra-faint dwarf (UFD) galaxies contain some of the oldest, most metal-poor stars in the universe. We present [Mg/Fe], [Si/Fe], [Ca/Fe], [Ti/Fe], and mean [α/Fe] abundance ratios for 61 individual red giant branch stars across eight UFDs. This is the largest sample of alpha abundances published to date in galaxies with absolute magnitudes MV > −8, including the first measurements for Segue 1, Canes Venatici II, Ursa Major I, and Leo T. Abundances were determined via medium-resolution Keck/DEIMOS spectroscopy and spectral synthesis. The sample spans the metallicity range −3.4 <[Fe/H] < −1.1. With the possible exception of Segue 1 and Ursa Major II, the individual UFDs show on average lower [α/Fe] at higher metallicities, consistent with enrichment from Type Ia supernovae. Thus, even the faintest galaxies have undergone at least a limited level of chemical self-enrichment. Together with recent photometric studies, this suggests that star formation in the UFDs was not a single burst, but instead lasted at least as much as the minimum time delay of the onset of Type Ia supernovae (∼100 Myr) and less than ∼2 Gyr. We further show that the combined population of UFDs has an [α/Fe] abundance pattern that is inconsistent with a flat, Galactic halo-like alpha abundance trend, and is also qualitatively different from that of the more luminous CVn I dSph, which does show a hint of a plateau at very low [Fe/H].