TEACHER-EVALUATORS’ NARRATIVE ACCOUNTS IN ASSESSING SELF-LEARNING MODULES (SLM)

This study aims to describe the narrative accounts of teacher-evaluators in assessing the quality of SLMs. This study uses a narrative research approach to examine five teacher-evaluators from the Koronadal City Division. As part of Bruner's theoretical framework, individuals produce new ideas or concepts based on prior information. Their expertise is needed to choose and process data. This study applies this approach because the cognitive structure organizes perceptions and helps individuals go beyond knowledge because evaluating self-learning material quality teaches teachers new concepts (SLMs). The finding reveals that participants feel honored and pressured, some are ready to carry out any assignment, and some are happy and excited. Participants indicated the advantage indicated learning new things and meaningful experiences, while the disadvantage indicated adding workloads. This research may support and motivate teacher-evaluators to tailor instruction to meet individual needs. Whether they differentiate content, process, products, or the learning environment, ongoing assessment and flexible grouping make this a successful approach to assessing students' SLMs quality. This study would provide a framework to build certain tasks, activities, or modules to motivate teachers and help them focus attention, organize information for understanding and remembering, monitor and assess learning, encourage self-monitoring, and self-correct tools for reflecting on and assessing their own learning in evaluating the quality assurance of SLM's.  Article visualizations

Critical nucleus charge in a superstrong magnetic field: effect of screening

A superstrong magnetic field stimulates the spontaneous production of positrons by naked nuclei by diminishing the value of the critical charge Z_{cr} . The phenomenon of screening of the Coulomb potential by a superstrong magnetic field which has been discovered recently acts in the opposite direction and prevents the nuclei with Z52 for a nucleus to become critical stronger B are needed than without taking screening into account.Comment: 13 pages, 2 figures, version to be published in Physical Review

ONLINE MULTIMEDIA SCREEN TIME AND LEVEL OF HAPPINESS OF THE COLLEGE STUDENTS

Online multimedia is very popular in today’s generation. Many people are using different online multimedia platforms as a means to enjoy, study, and connect with other people around the world. This study sought to determine the online multimedia screen time and the level of happiness of the college students of Notre Dame of Midsayap College as well as the relationship between these two variables. The researchers used descriptive- correlational research design and purposive sampling technique in gathering data through a survey questionnaire administered to 50 respondents who are active users of different online multimedia. The findings of the study revealed that online multimedia screen time and level of happiness have a significant relationship. Furthermore, contrary to the findings of previous studies, this study suggests that if online multimedia screen time is increased, students’ level of happiness also increases.  Article visualizations

Hydrogen Molecules In Superstrong Magnetic Field: II. Excitation Levels

We study the energy levels of H$_2$ molecules in a superstrong magnetic field (B\go 10^{12} G), typically found on the surfaces of neutron stars. The interatomic interaction potentials are calculated by a Hartree-Fock method with multi-configurations assuming electrons are in the ground Landau state. Both the aligned configurations and arbitrary orientations of the molecular axis with respect to the magnetic field axis are considered. Different types of molecular excitations are then studied: electronic excitations, aligned (along the magnetic axis) vibrational excitations, transverse vibrational excitations (a constrained rotation of the molecular axis around the magnetic field line). Similar results for the molecular ion H$_2^+$ are also obtained and compared with previous variational calculations. Both numerical results and analytical fitting formulae are given for a wide range of field strengths. In contrast to the zero-field case, it is found that the transverse vibrational excitation energies can be larger than the aligned vibration excitation, and they both can be comparable or larger than the electronic excitations. For B\go B_{crit}=4.23\times 10^{13} G, the Landau energy of proton is appreciable and there is some controversy regarding the dissociation energy of H$_2$. We show that H$_2$ is bound even for $B>>B_{crit}$ and that neither proton has a Landau excitation in the ground molecular state.Comment: Revtex (45 pages), 3 postscript figures; Phys. Rev. A in pres

Matter in Strong Magnetic Fields

The properties of matter are significantly modified by strong magnetic fields, $B>>2.35\times 10^9$ Gauss ($1 G =10^{-4} Tesla$), as are typically found on the surfaces of neutron stars. In such strong magnetic fields, the Coulomb force on an electron acts as a small perturbation compared to the magnetic force. The strong field condition can also be mimicked in laboratory semiconductors. Because of the strong magnetic confinement of electrons perpendicular to the field, atoms attain a much greater binding energy compared to the zero-field case, and various other bound states become possible, including molecular chains and three-dimensional condensed matter. This article reviews the electronic structure of atoms, molecules and bulk matter, as well as the thermodynamic properties of dense plasma, in strong magnetic fields, $10^9G << B < 10^{16}G$. The focus is on the basic physical pictures and approximate scaling relations, although various theoretical approaches and numerical results are also discussed. For the neutron star surface composed of light elements such as hydrogen or helium, the outermost layer constitutes a nondegenerate, partially ionized Coulomb plasma if $B<<10^{14}G$, and may be in the form of a condensed liquid if the magnetic field is stronger (and temperature $<10^6$ K). For the iron surface, the outermost layer of the neutron star can be in a gaseous or a condensed phase depending on the cohesive property of the iron condensate.Comment: 45 pages with 9 figures. Many small additions/changes. Accepted for publication in Rev. Mod. Phy

Metabolic changes in concussed American football players during the acute and chronic post-injury phases

<p>Abstract</p> <p>Background</p> <p>Despite negative neuroimaging findings many athletes display neurophysiological alterations and post-concussion symptoms that may be attributable to neurometabolic alterations.</p> <p>Methods</p> <p>The present study investigated the effects of sports concussion on brain metabolism using ¹H-MR Spectroscopy by comparing a group of 10 non-concussed athletes with a group of 10 concussed athletes of the same age (mean: 22.5 years) and education (mean: 16 years) within both the acute and chronic post-injury phases. All athletes were scanned 1-6 days post-concussion and again 6-months later in a 3T Siemens MRI.</p> <p>Results</p> <p>Concussed athletes demonstrated neurometabolic impairment in prefrontal and motor (M1) cortices in the acute phase where NAA:Cr levels remained depressed relative to controls. There was some recovery observed in the chronic phase where Glu:Cr levels returned to those of control athletes; however, there was a pathological increase of m-I:Cr levels in M1 that was only present in the chronic phase.</p> <p>Conclusions</p> <p>These results confirm cortical neurometabolic changes in the acute post-concussion phase as well as recovery and continued metabolic abnormalities in the chronic phase. The results indicate that complex pathophysiological processes differ depending on the post-injury phase and the neurometabolite in question.</p

INFINITELY MAGNETIZED HYDROGEN ATOM AND PULSAR CRUST

On examine quelques propriétés, importantes pour la structure des pulsars de l'atome d'hydrogène arbitrairement magnétisé. On montre que l'hypothèse de cylindrification forcée sous-jacente à l'Approximation Adiabatique (AA) demeure valable pour toute valeur de l'intensité magnétique B. On peut ainsi obtenir d'une manière unifiée, le spectre AA (B → ∞), celui du spectre diamagnétique (B faible), l'échelle dilatée de Landau à la limite d'ionisation (en l'absence d'effet Stark cinétique), et le spectre de Bohr (B = 0). On démontre que les corrections relativistes sont négligeables dans le fondamental. Ce qui permet de se limiter à un traitement non relativiste des propriétés statistiques de la surface des pulsars. Les effets de masse finie du proton sont également très faibles (≈ me/mp).A semi-classical approach is used to compute the very strongly magnetized H atom. Relativistic corrections to the ground state are shown to be negligible, as well as the finite proton mass effects

Nanothermodynamics of iron clusters: Small clusters, icosahedral and fcc-cuboctahedral structures

International audienceThe study of the thermodynamics and structures of iron clusters has been carried on, focusing on small clusters and initial icosahedral and fcc-cuboctahedral structures. Two combined tools are used. First, energy intervals are explored by the Monte Carlo algorithm, called σ-mapping, detailed in the work of Soudan et al. [J. Chem. Phys. 135, 144109 (2011), Paper I]. In its flat histogram version, it provides the classical density of states, gp(Ep), in terms of the potential energy of the system. Second, the iron system is described by a potential which is called “corrected EAM” (cEAM), explained in the work of Basire et al. [J. Chem. Phys. 141, 104304 (2014), Paper II]. Small clusters from 3 to 12 atoms in their ground state have been compared first with published Density Functional Theory (DFT) calculations, giving a complete agreement of geometries. The series of 13, 55, 147, and 309 atom icosahedrons is shown to be the most stable form for the cEAM potential. However, the 147 atom cluster has a special behaviour, since decreasing the energy from the liquid zone leads to the irreversible trapping of the cluster in a reproducible amorphous state, 7.38 eV higher in energy than the icosahedron. This behaviour is not observed at the higher size of 309 atoms. The heat capacity of the 55, 147, and 309 atom clusters revealed a pronounced peak in the solid zone, related to a solid-solid transition, prior to the melting peak. The corresponding series of 13, 55, and 147 atom cuboctahedrons has been compared, underscoring the unstability towards the icosahedral structure. This unstability occurs clearly in several steps for the 147 atom cluster, with a sudden transformation at a transition state. This illustrates the concerted icosahedron-cuboctahedron transformation of Buckminster Fuller-Mackay, which is calculated for the cEAM potential. Two other clusters of initial fcc structures with 24 and 38 atoms have been studied, as well as a 302 atom cluster. Each one relaxes towards a more stable structure without regularity. The 38 atom cluster exhibits a nearly glassy relaxation, through a cascade of six metastable states of long life. This behaviour, as that of the 147 atom cluster towards the amorphous state, shows that difficulties to reach ergodicity in the lower half of the solid zone are related to particular features of the potential energy landscape, and not necessarily to a too large size of the system. Comparisons of the cEAM iron system with published results about Lennard-Jones systems and DFT calculations are made. The results of the previous clusters have been combined with that of Paper II to plot the cohesive energy Ec and the melting temperature Tm in terms of the cluster atom number Nat. The N−1/3atNat−1/3 linear dependence of the melting temperature (Pawlow law) is observed again for Nat > 150. In contrast, for Nat < 150, the curve diverges strongly from the Pawlow law, giving it an overall V-shape, with a linear increase of Tm when Nat goes from 55 to 13 atoms. Surprisingly, the 38 atom cluster is anomalously below the overall curve

Nanothermodynamics of large iron clusters by means of a flat histogram Monte Carlo method

International audienceThe thermodynamics of iron clusters of various sizes, from 76 to 2452 atoms, typical of the catalyst particles used for carbon nanotubes growth, has been explored by a flat histogram Monte Carlo (MC) algorithm (called the σ-mapping), developed by Soudan et al. [J. Chem. Phys.135, 144109 (2011), Paper I]. This method provides the classical density of states, g p (E p ) in the configurational space, in terms of the potential energy of the system, with good and well controlled convergence properties, particularly in the melting phase transition zone which is of interest in this work. To describe the system, an iron potential has been implemented, called “corrected EAM” (cEAM), which approximates the MEAM potential of Lee et al. [Phys. Rev. B64, 184102 (2001)] with an accuracy better than 3 meV/at, and a five times larger computational speed. The main simplification concerns the angular dependence of the potential, with a small impact on accuracy, while the screening coefficients S ij are exactly computed with a fast algorithm. With this potential, ergodic explorations of the clusters can be performed efficiently in a reasonable computing time, at least in the upper half of the solid zone and above. Problems of ergodicity exist in the lower half of the solid zone but routes to overcome them are discussed. The solid-liquid (melting) phase transition temperature T m is plotted in terms of the cluster atom number N at . The standard N−1/3at linear dependence (Pawlow law) is observed for N at >300, allowing an extrapolation up to the bulk metal at 1940 ±50 K. For N at <150, a strong divergence is observed compared to the Pawlow law. The melting transition, which begins at the surface, is stated by a Lindemann-Berry index and an atomic density analysis. Several new features are obtained for the thermodynamics of cEAM clusters, compared to the Rydberg pair potential clusters studied in Paper I