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The goal of this article is to investigate Davydov’s concept of the concept against the backdrop of its philosophical system, namely, dialectical materialism. In the first part, after briefly sketching the context of Davydov’s work, I consider some ontological and epistemological ideas on which Davydov bases his concept of the concept. I pay particular attention to Hegel’s and Marx’s contributions. Then, I discuss Davydov’s concept of the concept and the relationship between the logical and the historical—a relationship that proved to be crucial in the making of the educational curricular program he and El’konin launched in the 1960s in Russia. I argue that, in tune with the dominant epistemology of the twentieth century, Davydov’s concept of the concept is based on a scientific outlook of the world, one in which theoretical scientific thought is considered the pinnacle of human cognition. I conclude with a critique that intends to place the notion of the concept in a broader dialectical materialist perspective.

In the strong light–matter coupling regime, the transmission properties of metasurfaces have a remarkable similarity to those of typical two-level systems. In this work, we explore the absorption spectra of a metasurface coupled to a quantum phonon bath using the time-dependent variational principle and the flexible multi-D2 Davydov trial states. In the weak light–matter coupling regime, phonon coupling has minimal impact on system dissipation. However, in the strong coupling regime, it significantly influences dissipation dynamics. Additionally, a phonon bath with a selected number of strongly coupled modes near the phonon center line substantially narrows the absorption spectrum linewidth by controlling dissipation through a few phonon channels. These findings demonstrate the critical role of the phonon bath in shaping metasurface transmission properties, offering a promising approach for the precise engineering of metasurfaces.

In this paper, we share details of a South African early grades’ number intervention informed by aspects of Davydov’s writing on early number teaching and learning. A key part of Davydov’s approach to early number teaching involves starting with attention to relationships between quantities rather than with counting. The Structuring Number Starters (SNS) intervention focused—over a nine-year period—on supporting early grades’ students to move beyond the calculating-by-counting approaches that are prevalent in South Africa. In attending to this focus, the intervention shifted increasingly towards an emphasis on relationships between quantities, though not in the same format or task sequence as advocated by Davydov. The contextual and cultural features that led to our adaptations—or shape-shifting—are highlighted in this paper. We interrogate key aspects of Davydov’s approaches to early number teaching in relation to key features typical of South African classroom mathematics teaching in order to understand the evolution of the SNS initiative. Quasi-longitudinal interview-based assessment data available from a cross-attainment sample of students in 2011, 2014 and 2018 indicate shifts over time from calculating-by-counting to calculating-by-structuring. These outcomes point to successes with moves into increasingly structured ways of working with early number, but suggest also that these successes may be contingent on some fluency with forward and backward number word sequences. The outcomes suggest that it is feasible to explore interventions directing attention to early number structure from the outset in larger scale studies.

This article discusses algebraic thinking regarding positive integers and rational numbers when students, 6 to 9 years old in multilingual classrooms, are engaged in an algebraic learning activity proposed by the El’konin and Davydov curriculum. The main results of this study indicate that young, newly arrived students, through tool-mediated joint reflective actions as suggested in the ED curriculum, succeeded in analysing arithmetical structures of positive integers and rational numbers. When the students participated in this type of learning activity, they were able to reflect on the general structures of numbers established as additive relationships (addition and subtraction) as well as multiplicative relationships (multiplication and division) and mixtures thereof, thus a core foundation of algebraic thinking. The students then used algebraic symbols, line segments, verbal, written, and gesture language to elaborate and construct models related to these relationships. This is in spite of the fact that most of the students were second language learners. Elaborated in common experiences staged in the lessons, the learning models appeared to bridge the lack of common verbal language as the models visualized aspects of the relationships among numbers in a public manner on the whiteboard. These learning actions created rich opportunities for bridging tensions in relation to language demands in the multilingual classroom.

A fully quantum, numerically accurate methodology is presented for the simulation of the exciton dynamics and time-resolved fluorescence of cavity-tuned two-dimensional (2D) materials at finite temperatures. This approach was specifically applied to a monolayer WSe2 system. Our methodology enabled us to identify the dynamical and spectroscopic signatures of polaronic and polaritonic effects and to elucidate their characteristic timescales across a range of exciton–cavity couplings. The approach employed can be extended to simulation of various cavity-tuned 2D materials, specifically for exploring finite temperature nonlinear spectroscopic signals.

The t-J model remains an indispensable construct in high-temperature superconductivity research, bridging the gap between charge dynamics and spin interactions within antiferromagnetic matrices. This study employs the multiple Davydov Ansatz method with thermo-field dynamics to dissect the zero-temperature and finite-temperature behaviors. We uncover the nuanced dependence of hole and spin deviation dynamics on the spin–spin coupling parameter J, revealing a thermally-activated landscape where hole mobilities and spin deviations exhibit a distinct temperature-dependent relationship. This numerically accurate thermal perspective augments our understanding of charge and spin dynamics in an antiferromagnet.

Purpose The aim of this study was to compare surgical and sexual outcomes after Davidov-Moore vaginoplasty in women with Mayer-Rokitansky-Küster-Hauser syndrome (MRKH). Methods In the case-series study, we described seven women, at a median age of 22.6 ± and BMI 22.8 ± 2.3 kg/m 2 . We measured peri- and postsurgical parameters, including surgery-related neovaginal length and sexual initiation time. Sexual outcomes were measured using the Female Sexual Function Index (FSFI) before and 6 months after vaginoplasty. Results All surgical procedures were performed successfully, with one minor perioperative bleeding. The mean time of vaginoplasty was 82.1 min and the mean duration of hospitalization was six days. After a 6-month follow-up, vaginal length was 8.1-times longer than before surgery (10 vs. 81 mm). The time from the surgery to the initiation of vaginal intercourse was between 17 to 22 weeks. The mean FSFI score indicated good results, with no women below 23 score, and was 4.3- times higher when compared with the pre-surgical one (6.7 vs 29.1). Contrary to the FSFI score before surgery, the post-surgical FSFI revealed higher scores in all six different domains: desire (2.5-times), arousal (4.1-times), lubrication (3.8-times), orgasm (3.4-times), satisfaction (3.3-times) and comfort (11-times). Conclusion Laparoscopic Davydov-Moore vaginoplasty might be considered as a safe procedure with satisfactory anatomic and sexual outcomes. It should be considered as a treatment option for the creation of neovagina in women with MRKH.

Background. While the current literature provides valuable insight into how school climate perceptions and student motivation impact academic achievement, research examining the mediating effects of motivation in the linking of an innovative educational system, school climate, and achievement is limited. This study considers the potential of the El’konin–Davydov system of developmental education as a basis for educational innovation. Self-determination theory is applied as a useful theoretical framework that allows for consideration of both the intensity and the quality of academic motivation. Objective. The study examines a model that illustrates the role of intrinsic and different types of extrinsic motivation in linking the El’konin–Davydov system of developmental education (DE) and school climate to the academic achievement of elementary schoolchildren. Design. Participants were 345 third and fourth graders drawn from four public schools in Moscow, with some (N = 192, 2 schools) educated in the traditional system and others (N = 153, 2 schools) in one that follows the DE system. A cross-sectional design was implemented. Results. Students in the DE system showed significantly lower external motivation for all three subscales (Parents, Teachers, General) and perceived school climate more favorably. Structural equation modeling showed that the hypothesized model fit the data well, supporting the hypothesis that student external motivation plays a mediating role in linking educational system (innovative vs. traditional) with academic achievement. Students’ autonomous motivation was shown to play a mediating role in linking positive perceptions of school climate with academic achievement. Conclusion. The elementary school students from developmental education classes compared to their peers from traditional education classes demonstrate more positive profile of academic motivation including lower external motivation, more positive attitude towards school and study; however, the two groups do not differ in the level of intrinsic, identified, and introjected motivations.

This study examines the collective mathematical reasoning when students and teachers in grades 3, 4, and 5 explore fractions derived from length comparisons, in a task inspired by the El´konin and Davydov curriculum. The analysis showed that the mathematical reasoning was mainly anchored in mathematical properties related to fractional or algebraic thinking. Further analysis showed that these arguments were characterised by interplay between fractional and algebraic thinking except in the conclusion stage. In the conclusion and the evaluative arguments, these two types of thinking appeared to be intertwined. Another result is the discovery of a new type of argument, identifying arguments, which deals with the first step in task solving. Here, the different types of arguments, including the identifying arguments, were not initiated only by the teachers but also by the students. This in a multilingual classroom with a large proportion of students newly arrived. Compared to earlier research, this study offers a more detailed analysis of algebraic and fractional thinking including possible patterns within the collective mathematical reasoning. An implication of this is that algebraic and fractional thinking appear to be more intertwined than previous suggested.

In the present paper we address the general problem of selective electrodynamic interactions between DNA and protein, which is motivated by decades of theoretical study and our very recent experimental findings providing a first evidence for their activation. Inspired by the Davydov and Holstein−Fröhlich models describing electron motion along biomolecules, and using a model Hamiltonian written in second quantization, the time-dependent variational principle is used to derive the dynamical equations of the system. We demonstrate the efficacy of this second-quantized model for a well-documented biochemical system consisting of a restriction enzyme, EcoRI, which binds selectively to a palindromic six-base-pair target within a DNA oligonucleotide sequence to catalyze a DNA double-strand cleavage. The time-domain Fourier spectra of the electron currents numerically computed for the DNA fragment and for the EcoRI enzyme, respectively, exhibit a cross-correlation spectrum with a sharp co-resonance peak. When the target DNA recognition sequence is randomized, this sharp co-resonance peak is replaced with a broad and noisy spectrum. Such a sequence-dependent charge transfer phenomenology is suggestive of a potentially rich variety of selective electrodynamic interactions influencing the coordinated activity of DNA substrates, enzymes, transcription factors, ligands, and other proteins under realistic biochemical conditions characterized by electron−phonon excitations.