Classical Level Research Articles

A generative adversarial network-based unsupervised domain adaptation method for magnetic resonance image segmentation

Intelligent medical image segmentation methods have been rapidly developed and applied, while a significant challenge is domain shift. That is, the segmentation performance degrades due to distribution differences between the source domain and the target domain. This paper proposed an unsupervised end-to-end domain adaptation medical image segmentation method based on the generative adversarial network (GAN). A network training and adjustment model was designed, including segmentation and discriminant networks. In the segmentation network, the residual module was used as the basic module to increase feature reusability and reduce model optimization difficulty. Further, it learned cross-domain features at the image feature level with the help of the discriminant network and a combination of segmentation loss with adversarial loss. The discriminant network took the convolutional neural network and used the labels from the source domain, to distinguish whether the segmentation result of the generated network is from the source domain or the target domain. The whole training process was unsupervised. The proposed method was tested with experiments on a public dataset of knee magnetic resonance (MR) images and the clinical dataset from our cooperative hospital. With our method, the mean Dice similarity coefficient (DSC) of segmentation results increased by 2.52% and 6.10% to the classical feature level and image level domain adaptive method. The proposed method effectively improves the domain adaptive ability of the segmentation method, significantly improves the segmentation accuracy of the tibia and femur, and can better solve the domain transfer problem in MR image segmentation.

Application of the Stad Learning Model to Improve Student Learning Outcomes in Grade IV SD Negeri 0701 Rattan Sogo

By applying the STAD type cooperative learning model assisted by video media, research was carried out to improve the learning outcomes of fourth grade students of SD Negeri 0701 Rotan Sogo whith material. This research is motivated by the fact that most students are less active and less interested in learning style material due to the lack of diversity in teacher performance during the learning process. The purpose of this study was to improve student learning outcomes at SD Negeri 0701 Rotan Sogo Class 4 Gaya. This type of research is classroom action research. The research subjects were all fourth grade students of SD Negeri 0701 Rotan Sogo, with a total of 34 students enrolled in the 2022/2023 academic year consisting of 17 male students and 17 female students. Data was collected through tests, observations, and interviews. The results showed that the use of the STAD type cooperative learning model assisted by video media could improve student learning outcomes for the style material. Classical learning completeness level data increased from 68% (pre-test) to 82% (period I) to 94% (period II). Observation of teacher activity increased from an average of 7.4 (period I) to 9.3 (period II). Observation of student activity increased from an average of 7.6 (cycle I) to 9.3 (cycle II)

Thick branes in Born–Infeld determinantal gravity in Weitzenböck spacetime

By adopting the idea of Born–Infeld electromagnetism, the Born–Infeld determinantal gravity in Weitzenböck spacetime provides a way to smooth the Big Bang singularity at the classical level. We consider a thick braneworld scenario in the higher-dimensional extension of this gravity, and investigate the torsion effects on the brane structure and gravitational perturbation. For three particular parameter choices, analytic domain wall solutions are obtained. They have a similar brane configuration that the brane thickness becomes thinner as the spacetime torsion gets stronger. For each model, the massless graviton is localized on the brane with the width of localization decreasing with the enhancement of the spacetime torsion, while the massive gravitons propagate in the bulk and contribute a correction term proportional to {1}/{(k r)^{3}} to the Newtonian potential. A sparsity constraint on the fundamental 5-dimensional gravitational scale is estimated from the gravitational experiment. Moreover, the parameter ranges in which the Kaluza–Klein gravitons are tachyonic free are analyzed.

Classical mass inflation versus semiclassical inner horizon inflation

We analyze the geometry of a spherically symmetric black hole with an inner and outer apparent horizon that is perturbed by spherical null shells of matter. On a classical level we observe that the mass inflation instability is triggered, resulting in a growth of curvature and an inward displacement of the inner horizon. We study in detail the inner structure of the mass-inflated region and compare it with previous results obtained for the case in which the perturbing matter content has a continuous distribution. We then perform an approximate calculation of the renormalized stress-energy tensor of a quantum field in the vicinity of the inner horizon, and analyze the semiclassical backreaction on this region of the geometry. We find that the classical tendency for this horizon to move inward due to mass inflation is challenged and potentially overcome by a semiclassical tendency for it to inflate outward.

Abrikosov-Nielsen-Olesen strings from the Coleman-Weinberg potential

We study properties of Abrikosov-Nielsen-Olesen (ANO) strings with the Coleman-Weinberg (CW) potential, which we call CW-ANO strings. While the scale-invariant scalar potential has a topologically trivial vacuum admitting no strings at the classical level, quantum correction allows topologically nontrivial vacua and stable string solutions. We find that the system of the CW potential exhibits significant difference from that of the conventional Abelian-Higgs model with the quadratic-quartic potential. While a single-winding string is qualitatively similar in both systems, and the static intervortex force between two strings at large distance is attractive/repulsive in the type-I/II regime for both, that between two CW-ANO strings exhibits a nontrivial structure. It develops an energy barrier between them at intermediate distance, implying that the string with winding number $n>1$ can constitute a metastable bound state even in the type-II regime. We name such a superconductor type-$\overline{1.5}$. We also discuss implications to high-energy physics and cosmology.

Interaction between magnon and skyrmion: Toward quantum magnonics

In recent years, magnon and spin texture are attracting great interest in condensed matter physics and magnetism. Magnonics is aiming to use magnon as information carriers to realize functions for storage, transmission, and processing. Magnetic skyrmion is representative spin texture due to its topologically nontrivial properties. Since skyrmions are topologically protected, their transformation to other spin configurations requires overcoming additional topological energy barriers. Therefore, skyrmions are more stable than other trivial spin textures. In addition, the characters of nanoscale size, quasiparticle properties, and various excitation modes make them a potential candidate for spintronic application. Magnon and skyrmion, as two fundamental excitations, can coexist in magnetic systems and interplay with each other through direct exchange interactions. In this review, we provide an overview of recent theoretical and experimental studies on magnon–skyrmion interactions. We mainly focus on three kinds of magnon–skyrmion interactions: (i) magnon scattering by skyrmion, (ii) skyrmion motion driven by magnon, and (iii) coupling between magnon and skyrmion modes. The first two kinds of interactions could be clearly explained by the wave-particle interaction model on the classical level. Alternatively, the last kind of interaction could be understood by the coupled harmonic oscillator model on the quantum level, which indicates fast energy exchange and hybrid magnon states. The exploration focused on quantum phenomena of magnon has led to the emerging field of quantum magnonics and promoted applications of magnon in quantum information storage and processing. In the end, we give a perspective on the exploration of magnon–skyrmion interaction in quantum magnonics.

The contour effect: Differences in the aesthetic preference and stress response to photo-realistic living environments.

The interest in the response to contours has recently re-emerged, with various studies suggesting a universal preference for curved over angular stimuli. Although no consensus has yet been reached on the reasons for this preference, similar effects have been proposed in interior environments. However, the scarcely available research primarily depends on schematic or unmatched stimuli and faces heterogeneity in the reported results. In a within-subject design, we investigated the claimed contour effect in photo-realistic indoor environments using stimulus material previously tested in virtual reality (VR). A total of 198 online participants rated 20 living room images, exclusively manipulated on the contours (angular vs. curved) and style (modern vs. classic) levels. The scales represented aesthetic (beauty and liking) and stress (rest and stress) responses. Beyond our main focus on contours, we additionally examined style and sex effects to account for potential interactions. Results revealed a significant main effect of contours on both aesthetic (η2 g = 1-2%) and stress (η2 g = 8-12%) ratings. As expected, images of curved (vs. angular) contours scored higher on beauty, liking, and rest scales, and lower on stress. Regarding interactions with style, curvature was aesthetically preferred over angularity only within images depicting modern interiors, however, its positive effect on stress responses remained significant irrespective of style. Furthermore, we observed sex differences in aesthetic but not in stress evaluations, with curvature preference only found in participants who indicated female as their sex. In sum, our study primarily confirms positive effects of curvature, however, with multiple layers. First, the impact on aesthetic preference seems to be influenced by individual and contextual factors. Second, in terms of stress responses, which might be especially relevant for designs intended to promote mental-health, the consistent effects suggest a more generalizable, potentially biophilic characteristic of curves. To the best of our knowledge, this is the first study to demonstrate these effects in fully-matched, photo-realistic, and multi-perspective interior design stimuli. From the background of a previous VR trial from our research group, whereby the same rooms did not elicit any differences, our findings propose that static vs. immersive presentations might yield different results in the response to contours.

Equivalence Principle in Classical and Quantum Gravity

We give a general overview of various flavours of the equivalence principle in classical and quantum physics, with special emphasis on the so-called weak equivalence principle, and contrast its validity in mechanics versus field theory. We also discuss its generalisation to a theory of quantum gravity. Our analysis suggests that only the strong equivalence principle can be considered fundamental enough to be generalised to a quantum gravity context since all other flavours of equivalence principle hold only approximately already at the classical level.

Different forms of silicon nanotubes and their interactions with DNA nucleotides: A molecular dynamics study

The interaction between different forms of silicon nanotubes (SiNTs) and DNA nucleotides is investigated using molecular dynamics simulations. The optimized geometries of infinite single-walled SiNTs made of hexagonal and tetragonal lattices are assessed at the classical level based on Tersoff and Stillinger-Weber potentials. Properties such as Si–Si bond length, diameters as well as formation energy per Si atom are calculated for different SiNTs. Our results for the armchair and zigzag structures show relatively good agreements with other classical and quantum level studies. Therefore, the same method is applied to the less investigated tetragonal type nanotubes. In the next step, the interaction between different DNA nucleotides and stable SiNTs is investigated. The results indicate that the van der Waals dispersion forces are mainly responsible for the nucleotide-SiNT interaction. A unique interaction feature of each nucleotide with SiNTs provides general guidelines for the design of SiNTs-based biosensors.

Fermionic matrix models and bosonization

We explore different limits of exactly solvable vector and matrix fermionic quantum mechanical models with quartic interactions at finite temperature. The models preserve a $U(1)\times SU(N)\times SU(L)$ symmetry at the classical level and we analyze them through bosonization techniques introducing scalar (singlet) and matrix (non-singlet) bosonic fields. The bosonic path integral representations in the vector limits $(N,1)$ and $(1,L)$ are matched to fermionic Fock space Hamiltonians expressed in terms of quadratic Casimirs and some additional terms involving the Cartan subalgebra, which makes explicit the symmetries preserved by scalar and matrix bosonizations at the quantum level. For the case of non-singlet bosonization we find an equivalence between the vector model and the Polychronakos+Frahm spin model. Using this relation we compute the free energy. Finally, we compute the eigenvalue distribution in the large $N,L$-limit with $ \alpha = \frac{L}{N}$ fixed. The model displays a third order phase transition as we vary the temperature which, in the $\alpha\gg1$ limit, can be characterized analytically. We conclude finding the critical curve in the parameter space were the eigenvalue distribution transitions from single to double cut.

Topological aspects in nonlinear optical frequency conversion

Nonlinear optical frequency conversion, observed more than half a century ago, is a corner stone in modern applications of nonlinear and quantum optics. It is well known that frequency conversion processes are constrained by conservation laws, such as momentum conservation that requires phase matching conditions for efficient conversion. However, conservation laws alone could not fully capture the features of nonlinear frequency conversion. Here it is shown that topology can provide additional constraints in nonlinear multi-frequency conversion processes. Unlike conservation laws, a topological constraint concerns with the conserved properties under continuous deformation, and can be regarded as a new indispensable degree of freedom to describe multi-frequency processes. We illustrate such a paradigm by considering sum frequency generation under a multi-frequency pump wave, showing that, akin topological phases in topological insulators, topological phase transitions can be observed in the frequency conversion process both at classical and quantum level.

TRADITIONAL GAMES IN IMPROVING LEARNING OUTCOMES OF SQUAT STYLE LONG JUMP IN ELEMENTARY SCHOOL STUDENTS

This study aims to improve the learning outcomes of the squat-style long jump through traditional games in grade VI A SD Agung Persada Bandar Khalipah. The problem in this study is how to improve the squat style long jump through traditional games for elementary school students. The research method used in this research was classroom action research. The population in this study were all students Class VI SD Agung Persada Bandar Khalipah, Deli Serdang Regency with 37 students. From the data analysis that has been done, it can be concluded that using traditional games can have an influence and improve learning outcomes in the squat style long jump. Where in the first learning outcomes test, the research results obtained that the percentage of the average value after conversion was 66.18 and the student's classical learning completeness level was 56.76%. Therefore, traditional games can be used as materials for ways to convey learning to students.

Close relationship between the dressed metric and the hybrid approach to perturbations in effective loop quantum cosmology

The dressed metric and the hybrid approach to perturbations are the two main approaches to capture the effects of quantum geometry in the primordial power spectrum in loop quantum cosmology. Both consider Fock quantized perturbations over a loop quantized background and result in very similar predictions except for the modes which exit the horizon in the effective spacetime in the Planck regime. Understanding precise relationship between both approaches has so far remained obscured due to differences in construction and technical assumptions. We explore this issue at the classical and effective spacetime level for linear perturbations, ignoring backreaction, which is the level at which practical computations of the power spectrum in both of the approaches have so far been performed. We first show that at the classical level both the approaches lead to the same Hamiltonian up to the second order in perturbations and result in the same classical mass functions in the Mukhanov-Sasaki equation on the physical solutions. At the effective spacetime level, the difference in phenomenological predictions between the two approaches in the Planck regime can be traced to whether one uses the Mukhanov-Sasaki variable $Q_{\vec k}$ (the dressed metric approach) or its rescaled version $\nu_{\vec k}=aQ_{\vec k}$ (the hybrid approach) to write the Hamiltonian of the perturbations, and associated polymerization ambiguities. It turns out that if in the dressed metric approach one chooses to work with $\nu_{\vec{k}}$, the effective mass function can be written exactly as in the hybrid approach, thus leading to identical phenomenological predictions in all regimes. Our results explicitly show that the dressed metric and the hybrid approaches for linear perturbations, at a practical computational level, can be seen as two sides of the same coin.

Analysis of MBLOCA and LBLOCA success criteria in VVER-1000/V320 reactors: New proposals for PSA Level 1

The specific configuration of the safety systems in VVER-1000/V320 reactors allows a comprehensive study of the Loss of Coolant Accident (LOCA). In the present paper, a verification of the success criteria of the event trees headers for the medium and large break LOCA sequences is conducted. A detailed TRACEV5P5 thermal-hydraulic model of the reactor has been developed, including all safety systems. When analyzing the results of all sequences, some conservatism is observed in certain specific configurations as the success criterion of some headers is not consistent with the classic PSA level 1. Therefore, new proposals for the LOCA event trees are performed based on a reconfiguration of LOCA break ranges and the use of the expanded event trees approach.

$T\bar{T}$ in JT Gravity and BF Gauge Theory

JT gravity has a first-order formulation as a two-dimensional BF theory, which can be viewed as the dimensional reduction of the Chern-Simons description of 3d3d gravity. We consider {T\overbar{T}}TT¯-type deformations of the (0+1)(0+1)-dimensional dual to this 2d2d BF theory and interpret the deformation as a modification of the BF theory boundary conditions. The fundamental observables in this deformed BF theory, and in its 3d3d Chern-Simons lift, are Wilson lines and loops. In the 3d3d Chern-Simons setting, we study modifications to correlators involving boundary-anchored Wilson lines which are induced by a {T\overbar{T}}TT¯ deformation on the 2d2d boundary; results are presented at both the classical level (using modified boundary conditions) and the quantum-mechanical level (using conformal perturbation theory). Finally, we calculate the analogous deformed Wilson line correlators in 2d2d BF theory below the Hagedorn temperature where the principal series dominates over the discrete series.

A pilot study on canonical gravity with mass dimension one fermions

The mass dimension one (MDO) fermionic field is built on a complete set of dual-helicity eigenspinors of the charge conjugation operator, which obeys the statistic of Fermi-Dirac. These spinors are a potential candidates for the description of dark matter. The redefinition of the dual structure of this object holds a local adjacent theory and completely satisfies the Lorentz invariance. In this work, we investigate important aspects of the interaction of this fermion with gravity in the light of a canonical formulation in ADM formalism. We construct an action via tetrad fields using a manifold on a family of spacelike surfaces Σt that carries the MDO matter field, and additionally we propose a condition for the action to have a term associated with dark energy. We found the Hamiltonian and diffeomorphism constraints at the classical level for gravitational dynamics with the immersion of this material content in space-time, which leads us to the interpretation of the contribution of dark matter energy density, parallel to the lapse function of foliation and its directional flux of energy density in the hypersurface of manifold.

U(1) CS theory vs SL(2) CS formulation: Boundary theory and Wilson line

We first derive the boundary theory from the U(1) Chern-Simons theory. The boundary action on an n-sheet manifold appears from its back-reaction of the Wilson line. The reason is that the U(1) Chern-Simons theory can provide an exact effective action when introducing the Wilson line. The Wilson line in the pure AdS3 Einstein gravity is equivalent to entanglement entropy in the boundary theory up to classical gravity. The U(1) Chern-Simons theory deviates by a self-interaction term from the gauge formulation on the boundary. We also compare the Hayward term in the SL(2) Chern-Simons formulation to the Wilson line approach. Introducing two wedges can reproduce the entanglement entropy for a single interval at the classical level. We propose quantum generalization by combining the bulk and Hayward terms. The quantum correction of the partition function vanishes. In the end, we calculate the entanglement entropy for a single interval. The pure AdS3 Einstein gravity theory shows a shift of central charge by 26 at the one-loop level. The U(1) Chern-Simons theory does not show a shift from the quantum effect. The result is the same in the weak gravitational constant limit. The non-vanishing quantum correction shows that the Hayward term is incorrect.

Mass Generation and Gravity

Despite the success of the Higgs mechanism to account for the generation of masses of the Standard Model (SM) elementary particles, the ultimate nature and origin of “mass” remain open questions in contemporary physics. From a foundational perspective, mass should be fundamentally related to the gravitational interaction and, according to Mach, with the structure of the Universe. In the present letter, a fully dynamical mass generation mechanism induced by higher-order corrections in the GR Lagrangian is discussed. Notably, the vacuum energy plays a key role in this process, which applies to both vector bosons and fermions. We show that, at the classical level, the Higgs mechanism can be though of as a particular case of the present mechanism.

Geometrodynamical description of two-dimensional electrodynamics

Two-dimensional pure electrodynamics is mapped into two-dimensional gravity in the first-order formalism at classical and quantum levels. Due to the fact that the degrees of freedom of these two theories do not match, we are enforced to introduce extra fields from the beginning. These fields are introduced through a BRST exact boundary term, so they are harmless to the physical content of the theory. The map between electromagnetism and gravity fields generate a non-trivial Jacobian, which brings extra features (but also harmless to the physical content of the gravity theory) at quantum level.

Peningkatan Keterampilan Memerankan Tokoh dengan Menggunakan Metode Sosiodrama Siswa Sekolah Dasar

The background of the research is the low achievement of learning Indonesian in drama material for fifth grade students at Pahlawan Elementary School, Bangkinang District, Kampar Regency, Riau. The low results of learning to play drama because students are not trained by teachers in playing drama characters, so students experience difficulties in acting out drama with proper pronunciation, intonation, expression, and appreciation. Learning with the sociodrama method was chosen, because in addition to training students' courage to play drama, it also makes students active in learning and develops cooperation within students. The purpose of this study was to improve the skills of playing drama characters in fifth grade students of SD Pahlawan. The subjects in the study were teachers and fifth grade students at SD Pahlawan, Bangkinang District, Kampar Regency, Riau. The number of students is 17 children, consisting of 7 male students and 10 female students. This research is a Classroom Action Research (CAR). Data collection methods used are tests, observations, and documentation. Prior to conducting the research, the researcher conducted preliminary observation activities through interviews. The data analysis technique in this study is quantitative descriptive statistics, namely by finding the average. The results showed that learning the skills of playing drama characters using the sociodrama method could improve the skills of playing the characters of the fifth grade students of SD Pahlawan. Class average results in cycle I average student score of 67.47 with classical completeness of 70.58% (11 students). In cycle II, the average score of students increased again to 77 with a classical mastery level of 88.23% (15 students). From the data obtained, it can be concluded that the sociodrama method can improve learning outcomes and student activity in drama material.