Unitary Approach Research Articles

Theoretical study of N(1535) and Σ*(1/2−) in the Cabibbo-favored process Λc+→pK¯0η

Motivated by the recent experimental measurements, we have investigated the Cabibbo-favored process Λc+→pK¯0η, where the N(1535) resonance is dynamically generated from the S-wave pseudoscalar meson-octet baryon interactions within the chiral unitary approach. The contributions from the intermediate N(1650) and the predicted low-lying baryon Σ*(1/2−) are also considered. In addition, a Breit-Wigner amplitude for the N(1535) resonance is checked. By comparing with the measured ηp, K¯0η, and pK¯0 invariant mass squared distributions, our results support the interpretation of N(1535) as a dynamically generated state. Furthermore, we demonstrate that, with the contribution from Σ*(1/2−) taken into account, the calculated invariant mass distributions agree with the Belle measurements. Future precise measurements of the Λc+→pK¯0η process can further elucidate the existence of the low-lying baryon Σ*(1/2−). Published by the American Physical Society 2024

Renormalized Internally Contracted Multireference Coupled Cluster with Perturbative Triples.

In this work, we combine the many-body formulation of the internally contracted multireference coupled cluster (ic-MRCC) method with Evangelista's multireference formulation of the driven similarity renormalization group (DSRG). The DSRG method can be viewed as a unitary multireference coupled cluster theory, which renormalizes the amplitudes based on a flow equation approach to eliminate numerical instabilities. We extend this approach by demonstrating that the unitary flow equation approach can be adapted for nonunitary transformations, rationalizing the renormalization of ic-MRCC amplitudes. We denote the new approach, the renormalized ic-MRCC (ric-MRCC) method. To achieve high accuracy with a reasonable computational cost, we introduce a new approximation to the Baker-Campbell-Hausdorff expansion. We fully consider the linear commutator while approximating the quadratic commutator, for which we neglect specific contractions involving amplitudes with active indices. Moreover, we introduce approximate perturbative triples to obtain the ric-MRCCSD[T] method. We demonstrate the accuracy of our approaches in comparison to advanced multireference methods for the potential energy curves of H8, F2, H2O, N2, and Cr2. Additionally, we show that ric-MRCCSD and ric-MRCSSD[T] match the accuracy of CCSD(T) for evaluating spectroscopic constants and of full configuration interaction energies for a set of small molecules.

On imperfective suffixes in Russian

This article is concerned with imperfective suffixes in Russian. It argues that there are at least three imperfective suffixes, the progressive morpheme, the iterative marker and the habitual suffix. It is shown that they differ in morphosyntactic and semantic properties. As to their structural properties, the progressive suffix is the lowest marker; the iterative morpheme attaches in a higher position; and the habitual morpheme is structurally the highest element. Thus, the article argues against a unitary approach to the iterative suffix and the habitual morpheme. Semantically, the iterative suffix has a pluractional meaning, whereas the habitual suffix is a vague generic quantifier. As to their phonological properties, the three markers are homophonous; they are spelled out as an -yva- allomorph. In this respect, the suffixes differ from the morphological aspect operator encoding (im)perfectivity in the aspectual head, which is phonologically empty. Further, it is shown that there are certain prefixes in the verbal morphosyntactic structure that are placed between the progressive projection and the iterative projection.

Two states for the Ξ(1820) resonance

We recall that the chiral unitary approach for the interaction of pseudoscalar mesons with the baryons of the decuplet predicts two states for the Ξ(1820) resonance, one with a narrow width and the other one with a large width. We contrast this fact with the recent BESIII measurement of the K−Λ mass distribution in the ψ(3686) decay to K−ΛΞ¯+, which demands a width much larger than the average of the PDG, and show how the consideration of the two Ξ(1820) states provides a natural explanation to the experimental data.

The Miami Framework for ALS and related neurodegenerative disorders: an integrated view of phenotype and biology.

Increasing appreciation of the phenotypic and biological overlap between amyotrophic lateral sclerosis (ALS) and frontotemporal dementia, alongside evolving biomarker evidence for a pre-symptomatic stage of disease and observations that this stage of disease might not always be clinically silent, is challenging traditional views of these disorders. These advances have highlighted the need to adapt ingrained notions of these clinical syndromes to include both the full phenotypic continuum - from clinically silent, to prodromal, to clinically manifest - and the expanded phenotypic spectrum that includes ALS, frontotemporal dementia and some movement disorders. The updated clinical paradigms should also align with our understanding of the biology of these disorders, reflected in measurable biomarkers. The Miami Framework, emerging from discussions at the Second International Pre-Symptomatic ALS Workshop in Miami (February 2023; a full list of attendees and their affiliations appears in the Supplementary Information) proposes a classification system built on: first, three parallel phenotypic axes - motor neuron, frontotemporal and extrapyramidal - rather than the unitary approach of combining all phenotypic elements into a single clinical entity; and second, biomarkers that reflect different aspects of the underlying pathology and biology of neurodegeneration. This framework decouples clinical syndromes from biomarker evidence of disease and builds on experiences from other neurodegenerative diseases to offer a unified approach to specifying the pleiotropic clinical manifestations of disease and describing the trajectory of emergent biomarkers.

Study of the B−→K−ηηc decay due to the DD¯ bound state

We study the B−→K−ηηc decay by taking into account the S-wave contributions from the pseudoscalar meson-pseudoscalar meson interactions within the unitary coupled-channel approach, where the DD¯ bound state is dynamically generated. In addition, the contribution from the intermediate resonance K0*(1430)−, with K0*(1430)−→K−η, is also considered. Our results show that there is a clear peak around 3720 MeV in the ηηc invariant mass distribution, which could be associated with the DD¯ bound state. The future precise measurements of the B−→K−ηηc process at the Belle II and LHCb experiments could be, therefore, used to check the existence of the DD¯ bound state, and to deepen our understanding of the hadron-hadron interactions. Published by the American Physical Society 2024

Interactions of the pseudoscalar meson octet and the baryon decuplet in the continuum and a finite volume

This study focuses on the interaction of the pseudoscalar meson octet and the baryon decuplet. In the continuum, it is observed that several JP=32-\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$J^{P}=\\frac{3}{2}^-$$\\end{document} baryon resonances can be produced by the Weinberg-Tomozawa interaction in unitarized chiral perturbation theory, including the N(1875), Σ(1670)\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$\\Sigma (1670)$$\\end{document}, Σ(1910)\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$\\Sigma (1910)$$\\end{document}, Ξ(1820)\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$\\Xi (1820)$$\\end{document} and Ω(2012)\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$\\Omega (2012)$$\\end{document}. Among them, the Ξ(1820)\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$\\Xi (1820)$$\\end{document} and Σ(1670)\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$\\Sigma (1670)$$\\end{document} may exhibit a potential two-pole structures. The unitarized chiral perturbation approach is then applied as the underlying theory to predict the energy levels of these systems in a finite volume. These energy levels are well described by the K-matrix parameterization constrained by flavor SU(3) symmetry. With the parameters from the best fits, the poles extracted from the K-matrix parameterization closely correspond to those derived from the underlying chiral effective field theory, as long as they are close to physical region and not significantly higher than the lowest relevant threshold.

IMPLEMENTAREA UNEI DOCTRINE A SPRIJINULUI PRIN FOC DE NIVEL ÎNTRUNIT – CERINȚĂ A OPERAȚIEI ÎNTRUNITE

Implementing a Joint Fire Support Doctrine – Requirement for the Joint OperationAbstract: In this paper we wanted to highlight the importance of developing and implementing in the Romanian Army a jointfire support doctrine that will serve as foundation for common and coherent understanding of specific concepts and terminology forfire support in every branch of the armed forces. The unitary approach and understanding of these concepts constitute a fundamentalneed to provide timely, integrated and synchronized fire support in a joint operation.Although, at Land Forces level, “F.T.-6 – Fire support manual for group force operations” was developed in 2018, and comprisesfire support fundamentals, this manual cannot be sufficient and, in our opinion, a dedicated norm that implements fire support specificprinciples, tactics, techniques and procedures at every armed force branch is required, for responsible personnel with fire support andalso with joint targeting, no matter what force structures are generated for the joint operation. In order to achieve this requirement,we believe it is necessary to develop a dedicated doctrine at the highest national military authority regarding joint fire support, inorder to implement fire support fundamentals in every army branch of the Romanian Army – aspects that currently exist in the landforces manual, as every army branch can contribute with force structures or specialized elements to providing fire support in a jointoperation.

Unitarity, real-intermediate states, and fixed-order approach to resonant dark matter annihilation

Unitarity, real-intermediate states, and fixed-order approach to resonant dark matter annihilation

Modeling the effect of shape deformation induced by gravity on the evaporation of pendant and sessile drops

Pendant and sessile drops form a spherical cap only in the absence of gravity. The effect of gravity on drop shape is often neglected on the basis of the assumption that the drop size is smaller than the capillary length [Lc=(σ/gρ)1/2], although the deformation may not be fully negligible even in those cases. This paper focuses on evaluation of the effect that deformation due to gravity has on the evaporation characteristics of pendant and sessile drops. The drop shape is described by the Bashforth–Adams equation, a non-linear second order ordinary differential equation, which is solved numerically using a Runge–Kutta method with variable time steps. Under quasi-steady approximation, the species and energy conservation equations in the gas phase have analytical solutions, even for temperature-dependent gas thermophysical properties, once the solution of a basic Laplace problem is known. The Laplace equation is solved in axial symmetric geometry by using COMSOL Multiphysics®, for a wide range of drop sizes and contact angles, yielding vapor distribution, vapor fluxes, and evaporation rates. Comparison with the results from drops of same size in microgravity (i.e., having a spherical cap shape) shows that the effect is also perceptible for drops with a size smaller than the capillary length and that it can become quite important for those with larger sizes. Complementary results are found for sessile and pendant drops with respect to wall wettability, suggesting that the phenomenon can be analyzed using a unitary approach.

A unified approach to three themes in harmonic analysis (I & II): (I) The linear Hilbert transform and maximal operator along variable curves (II) Carleson type operators in the presence of curvature

This paper constitutes the first part of a study that addresses three rich historical themes in harmonic analysis that, in the non-zero curvature setting, investigate the boundedness properties along variable curves for(I) the linear Hilbert transform and analogous maximal operator,(II) the Carleson-type operators, and(III) the bilinear Hilbert transform and analogous maximal operator.Our Main Theorem in this paper states that, given a general variable curve γ(x,t) in the plane that is assumed only to be measurable in x and to satisfy suitable non-zero curvature in t and extra (mild) non-degeneracy conditions, the operators at (I) and (II) defined along the curve γ are Lp-bounded for 1<p<∞.Our result provides a new and unified treatment of the first two themes as well as a unitary approach within the x-variable setting for both the singular integral and the maximal operator versions of (I).At the heart of our approach is the LGC–methodology introduced here, which encompasses three key ingredients:(1)phase/space discretization that confines the phase of the multiplier to oscillate at the linear level,(2)adapted Gabor frame discretization of the input function(s), and(3)cancelation extraction via the analysis of the time-frequency correlation(s) capturing the non-zero curvature of γ.

Spin-Adapted Externally Contracted Multireference Configuration Interaction Method Based on Selected Reference Configurations.

As one kind of approximation of the full configuration interaction solution, the selected configuration interaction (sCI) methods have been shown to be valuable for large active spaces. However, the inclusion of dynamic correlation beyond large active spaces is necessary for more quantitative results. Since the sCI wave function can provide a compact reference for multireference methods, previously, we proposed an externally contracted multireference configuration interaction method using the sCI reference reconstructed from the density matrix renormalization group wave function [J. Chem. Theory Comput. 2018, 14, 4747-4755]. The DMRG2sCI-EC-MRCI method is promising for dealing with more than 30 active orbitals and large basis sets. However, it suffers from two drawbacks: spin contamination and low efficiency when using Slater determinant bases. To solve these problems, in this work, we adopt configuration state function bases and introduce a new algorithm based on the hybrid of tree structure for convenient configuration space management and the graphical unitary group approach for efficient matrix element calculation. The test calculation of naphthalene shows that the spin-adapted version could achieve a speed-up of 6.0 compared with the previous version based on the Slater determinant. Examples of dinuclear copper(II) compound as well as Ln(III) and An(III) complexes show that the sCI-EC-MRCI can give quantitatively accurate results by including dynamic correlation over sCI for systems with large active spaces and basis sets.

J/ψ\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$\\varvec{J/\\psi }$$\\end{document} decays into ω(ϕ)f1(1285)\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$\\omega (\\phi ) f_1(1285)$$\\end{document} and ω(ϕ)``f1(1420)\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$\\omega (\\phi ) ``f_1(1420)$$\\end{document}”

We perform a theoretical study of the J/ψ→ω(ϕ)K∗K¯+c.c.→ω(ϕ)K0π+K-\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$J/\\psi \\rightarrow \\omega (\\phi ) K^* \\bar{K} + c.c. \\rightarrow \\omega (\\phi ) K^0 \\pi ^+ K^-$$\\end{document} reactions with the assumption that the f1(1285)\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$f_1(1285)$$\\end{document} is dynamically generated from a single channel K∗K¯+c.c\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$K^* \\bar{K} + c.c$$\\end{document} interaction in the chiral unitary approach. Two peaks in the K0π+K-\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$K^0 \\pi ^+ K^-$$\\end{document} invariant mass distribution are observed, one clear peak locates at the f1(1285)\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$f_1(1285)$$\\end{document} nominal mass, the other peak locates at around 1420MeV\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$1420 \ ext {MeV}$$\\end{document} with about 70MeV\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$70 \ ext {MeV}$$\\end{document} width. We conclude that the former peak is associated with the f1(1285)\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$f_1(1285)$$\\end{document} and the latter peak is not a genuine resonance but a manifestation of the kinematic effect in the higher energy region caused by the K∗K¯+c.c.\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$K^* \\bar{K} + c.c.$$\\end{document} decay mode of the f1(1285)\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$f_1(1285)$$\\end{document}.

Analysis of 𝚵(1620) resonance with chiral unitary approach

Abstract. Recently, the ξ(1620) resonance has attracted much attention, thanks to detailed experimental data by the Belle and ALICE collaborations. This experimental progress has prepared us to conduct theoretical analyses based on experimental data. In this study, we analyze the ξ(1620) resonance using the chiral unitary model and discuss the properties of the ξ(1620) resonance and the K−Λ scattering length.

Continuous unitary transformation approach to the Kondo–Majorana interplay

We analyze a setup composed of a correlated quantum dot (QD) coupled to one metallic lead and one end of topological chain hosting a Majorana zero mode (MZM). In such a hybrid structure, a leakage of the MZM into the region of the QD competes with the Kondo resonance appearing as a consequence of the spin-exchange interactions between the dot and the lead. In the work, we use the nontrivial technique called the continuous unitary transformation (CUT) to analyze this competition. Using the CUT technique, we inspect the influence of the coupling between the QD and the chain on effective exchange and density–density interactions.

Моделі споживчої поведінки домогосподарств: еволюція від унітарних до колективних.

The problems of estimating and forecasting the economic behavior of households attract more and more attention of scientists, experts and even politicians. This is explained mainly by the popularity of modern tools for ex-ante assessment of the impact of economic and social reforms on the most important aspects of the population’s life: consumption of goods and services, economic activity, needs for social support, satisfaction with the standard of living and living conditions, etc. The article, which is primarily an overview, examines the peculiarities of the formation and development of unitary and collective models of consumer behavior of households, as a theoretical basis for the development of applied tools for evaluating corresponding economic processes. The main principles of creating unitary and collective models are highlighted, and the main advantages of the collective approach are substantiated. Some attention is paid to the role of the Pareto principle of efficient resource allocation in modeling the household behavior, and to the problems of forming equivalence scales of household incomes and expenditures. Issues of the effectiveness of the microsimulation approach in the development of applied tools for assessing the economic behavior of households, and the formation of an information support system for microsimulation modeling are discussed. It is noted that although microsimulation modeling is a relatively new area of research on the household economic behavior, it can ensure the development of adequate and effective applied reduced collective models. The characteristics of the household time use survey, as one of the main data sources for creating collective models, are given. The importance of the availability of representative microdata sets of other sample surveys characterizing both households and their members, in particular, such as the household income and living conditions sample surveys and labor force surveys is noted. The purpose of the article is to assess the evolution of economic models of household consumption behavior from unitary to collective, to determine the essence and advantages of collective models, to identify opportunities and effective ways of their practical usage for modeling the behavior of Ukrainian households. The novelty of the article is in the study of models of household behavior both in the historical perspective and from the point of view of increasing their adequacy based on more realistic assumptions and ways of formalizing models, determining the prospects of a microsimulation approach for the development of applied collective models. In the process of preparing the article, while summarizing the experience of scientific research in the field of modeling the economic behavior of households, methods of deduction and induction, analysis and synthesis were used. Comparison method made it possible to compare the unitary and collective approaches in modeling the consumer behavior of households, identify their similarities and differences. The conclusions summarize the main theses of the article and highlight the main directions of further research.

The a0(980) in the single Cabibbo-suppressed process Λc → π0ηp

In this work, we have investigated the Cabibbo-suppressed process Λc→π0ηp, by taking into account the intermediate scalar state a0(980), which could be dynamically generated from the S-wave pseudoscalar-pseudoscalar interaction within the chiral unitary approach. We have calculated the π0η invariant mass distribution, and found that there is a significant structure associated to the a0(980). We have also roughly estimated the branching fraction B(Λc→π0ηp)∼10−4. We encourage our experimental colleagues to measure the process Λc→π0ηp for searching for the state a0(980) in this reaction.

Dynamics of Dispersive Measurements of Flux-Qubit States: Energy-Level Splitting Connected to Quantum Wave Mechanics.

Superconducting flux qubits have many advantages as a storage of quantum information, such as broad range tunability of frequency, small-size fabricability, and high controllability. In the flux qubit-oscillator, qubits are connected to SQUID resonators for the purpose of performing dispersive non-destructive readouts of qubit signals with high fidelity. In this work, we propose a theoretical model for analyzing quantum characteristics of a flux qubit-oscillator on the basis of quantum solutions obtained using a unitary transformation approach. The energy levels of the combined system (qubit + resonator) are analyzed in detail. Equally spaced each energy level of the resonator splits into two parts depending on qubit states. Besides, coupling of the qubit to the resonator brings about an additional modification in the split energy levels. So long as the coupling strength and the tunnel splitting are not zero but finite values, the energy-level splitting of the resonator does not disappear. We conclude that quantum nondemolition dispersive measurements of the qubit states are possible by inducing bifurcation of the resonator states through the coupling.

Towards a ‘pluralist’ approach for examining structures of interwoven multimodal discourse on social media

This study proposes a framework for examining hashtagged content on social media, which captures how specific issue frames (i.e. hashtags) contribute to navigable structures. We introduce ‘interwoven multimodal discourse’ as a pluralist alternative to the widely applied unitary approach in which trending hashtags serve as primary sites of analysis. The study argues that ‘interweaving’ of social media discourse takes place through practices such as hashtag colocation, which result in ambient and navigable structures. Analysis of hashtag colocation networks can serve as an approach for mapping ambient affiliations accessible through such structures. We analyse a hashtag colocation network constructed using a sample of 1100 Instagram posts related to climate change uploaded during the United Nations Climate Change Conference 2021 (COP26) held in Glasgow to demonstrate two structural properties of interwoven discourse on Instagram: (1) hashtags contribute to multiple thematic clusters and (2) micro-level hashtags representing secondary topics are nested within larger thematic clusters.

Instructional efficiency: The role of prior knowledge and cognitive load

AbstractWe used a 2 (prior knowledge: low vs. high) × 4 (instructional approach: unitary vs. unitary‐pictorial vs. equation vs. equation‐pictorial) ANOVA to examine the relationship between instructional approach, student prior knowledge, and personal belief of best practice for learning of the find‐whole percentage problems, which pose a challenge for many middle school students. The unit percentage concept is central to both the unitary approach and the unitary‐pictorial approach, where the latter has a diagram to scaffold the unit percentage concept. Both the equation approach and the equation‐pictorial approach, in contrast, are algebra approaches that integrate relevant information to form an equation, allowing learners to solve for an unknown (e.g., x). Furthermore, the equation‐pictorial approach relies on the proportional concept, scaffolded by a diagram to form an equation. A student's best practice, reflected by what is known as the ‘actual – optimal bests dichotomy’, details her belief in capability to perform task complexity (i.e., simple task vs. complex task). The concept of element interactivity within cognitive load theory framework predicts differential instructional efficiency: equation‐pictorial &gt; equation approach &gt; unitary‐pictorial &gt; unitary. Our findings (N = 218 secondary students) showed that performance outcomes favored high prior knowledge students for complex problems and, to a lesser extent, practice problems and simple problems. Low prior knowledge students benefitted most from the equation‐pictorial approach, and they invested higher mental effort than high prior knowledge students across three approaches (unitary, unitary‐pictorial, equation) but not the equation‐pictorial approach. Importantly, cognitive load imposition, by proxy of students' mental effort, was unrelated to students' belief in optimal best.