Action Of Group Research Articles

Perceptions of Black faculty encounters with racism through a collaborative autoethnographical lens: CRT and moral reasoning perspectives

Foreign-born scholars as allies from non-advantaged minoritized groups have historically provided critical insights about the racism that is directed at Black people in a racially driven U.S. society. The current collaborative autoethnography is based on the intersecting paths of three university faculty, a Black female scholar and two international J-1 scholars, who documented through personal narratives the racism that is directed at Black faculty at PWIs, drawing from critical race and moral reasoning interpretative frameworks. Building on previous research, the narratives shed light on how anti-Black racism persists at PWIs in the form of micro-aggressions and race-based hostility and that humanizing reparation efforts are warranted but may not be sufficient to ensure comprehensive change. Future research must explore the potential impact of group action initiatives among BIPOC and other minoritized faculty groups (national, international) to promote faculty protections in general while challenging anti-Black racism specifically.

A self-healing polyurethane/imidazole-modified carboxylated graphene oxide composite coating for antifouling and anticorrosion applications

Marine corrosion and biofouling present significant challenges to maintaining maritime vessels and oceanic infrastructure. Developing coatings that integrate anti-fouling, anti-corrosion, and self-healing properties remains a critical issue. This study introduces imidazolium-modified carboxylated graphene (FCGO) into polyurethane coatings (F-PUSS) containing disulfide bonds to address this challenge. The incorporation of FCGO significantly enhances the mechanical properties of the coating, improving tensile stress by 40 % to 20.97 MPa. The barrier properties of FCGO also provide strong corrosion resistance, with |Z|0.01Hz values an order of magnitude higher than the original samples, even after 15 days of immersion in sodium chloride (3.5 wt%). Additionally, F-PUSS retains corrosion resistance after repairs. The synergistic action of imidazole groups and graphene provides excellent antifouling performance with nearly to an alga rate of 100 % and an antimicrobial rate of 96 %. F-PUSS demonstrates remarkable self-healing capabilities, with a healing efficiency of 78 % after 48 h at 60 °C. This study provides valuable insights for designing multifunctional polymer materials with anti-fouling, anti-corrosion, and self-healing functions.

Repelling Planet Pairs by Ping-pong Scattering

The Kepler mission reveals a peculiar trough-peak feature in the orbital spacing of close-in planets near mean-motion resonances: a deficit and an excess that are, respectively, a couple of percent interior to and wide of the resonances. This feature has received two main classes of explanations: one involving eccentricity damping and the other scattering with small bodies. Here, we point out a few issues with the damping scenario and study the scattering scenario in more detail. We elucidate why scattering small bodies tends to repel two planets. As the small bodies random-walk in energy and angular momentum space, they tend to absorb fractionally more energy than angular momentum. This, which we call “ping-pong repulsion,” transports angular momentum from the inner to the outer planet and pushes the two planets apart. Such a process, even if ubiquitous, leaves identifiable marks only near first-order resonances: diverging pairs jump across the resonance quickly and produce the mean-motion resonance asymmetry. To explain the observed positions of the trough-peaks, a total scattering mass of order a few percent of the planet masses is required. Moreover, if this mass is dominated by a handful of Mercury-sized bodies, one can also explain the planet eccentricities as inferred from transit-time variations. Last, we suggest how these conditions may have naturally arisen during the late stages of planet formation.

A Cortical-Inspired Contour Completion Model Based on Contour Orientation and Thickness

An extended four-dimensional version of the traditional Petitot–Citti–Sarti model on contour completion in the visual cortex is examined. The neural configuration space is considered as the group of similarity transformations, denoted as M=SIM(2). The left-invariant subbundle of the tangent bundle models possible directions for establishing neural communication. The sub-Riemannian distance is proportional to the energy expended in interneuron activation between two excited border neurons. According to the model, the damaged image contours are restored via sub-Riemannian geodesics in the space M of positions, orientations and thicknesses (scales). We study the geodesic problem in M using geometric control theory techniques. We prove the existence of a minimal geodesic between arbitrary specified boundary conditions. We apply the Pontryagin maximum principle and derive the geodesic equations. In the special cases, we find explicit solutions. In the general case, we provide a qualitative analysis. Finally, we support our model with a simulation of the association field.

Augmented reality and optical navigation assisted orbital surgery: a novel integrated workflow

Abstract Objectives Due to the close topographical relationship of functional relevant anatomic structures, limited space and cosmetic aspects orbital surgery will remain a challenging discipline. Therefore, novel technical capabilities are necessary for further surgical progress. We here tested the integration of augmented reality and optical navigation in one workflow for interdisciplinary decision-making, feasibility and intraoperative guidance. Methods High-resolution contrast-enhanced MRI and CT scans were automated and manual-assisted segmented to achieve a detailed three-dimensional (3D) model of the individual patho-anatomical relationships. Augmented reality was used for interdisciplinary preoperative planning and intraoperative intuitive navigation. Mayfield clamp head holder in combination with optical surface matching registration assured navigation assisted microsurgery. Results Combinations of different MRI-sequences and CT-scans were necessary for detailed 3D-modeling. Modeling was time consuming and only viable in the hands of medical, surgical and anatomical trained staff. Augmented reality assured a quick, intuitive interdisciplinary orientation. Intraoperative surface matching registration enabled precise navigation in the orbital space. Conclusions Optical Navigation and microscope integration achieved a straightforward microsurgical workflow and should be implemented regularly. Augmented reality represented a useful tool for preoperative interdisciplinary planning and intraoperative intuitive orientation. It further stated an excellent educational tool.

The number of Hamiltonian cycles in groups of Symmetry

Groups are algebraic structures in Abstract Algebra comprised of a set of elements with a binary operation that satisfies closure, associativity, identity and invertibility. Cayley graphs serve as a visualization tool for groups, as they are capable of illustrating certain structures and properties of groups geometrically. In particular, each element in a group is assigned to a vertex in Cayley graphs. By the group action of left-multiplication, distinct elements in the generating sets can act on each element to create varied directed edges (Meier[1]). By contrast, the presence of a Hamiltonian cycles within a graph demonstrates its level of connectivity. In this research paper, utilizing directed Cayley graphs, we present a series of conjectures and theorems regarding the number and existence of Hamiltonian cycles within Dihedral groups, Symmetric groups of Platonic solids and Symmetric groups. By exploring the relationship between Abstract groups and Hamiltonian graphs, this work contributes to the broader field of research pertaining to Groups of Symmetry and Geometric Group Theory.

Minimal Compact Group Actions on C*-Algebras with Simple Fixed Point Algebras

Minimal Compact Group Actions on C*-Algebras with Simple Fixed Point Algebras

Symmetry reduction and recovery of trajectories of optimal control problems via measure relaxations

We address the problem of symmetry reduction of optimal control problems under the action of a finite group from a measure relaxation viewpoint. We propose a method based on the moment-SOS (Sum of Squares) aka Lasserre hierarchy which allows one to significantly reduce the computation time and memory requirements compared to the case without symmetry reduction. We show that the recovery of optimal trajectories boils down to solving a symmetric parametric polynomial system. Then we illustrate our method on the symmetric integrator and the time-optimal inversion of qubits.

Domains of discontinuity of Lorentzian affine group actions

We prove nonemptyness of domains of proper discontinuity of Anosov groups of affine Lorentzian transformations of Rn\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$${\\mathbb R}^n$$\\end{document}.

With sensitive eyes: ECEC teachers’ visual gaze and related reflections on pedagogical actions in toddler groups using eye-tracking glasses

This study explored early childhood education and care (ECEC) teachers’ visual gaze and related reflections on pedagogical actions during pedagogical activities in groups of children under three years of age in Finland. The data were collected from play and teacher-guided activities using mobile eye-tracking glasses, the retrospective thinking aloud (RTA) method, and semi-structured interviews. The results showed that even though the teachers were surprised about some aspects of the visual gaze metrics, they reflected on and gave reasons for their visual gazes on children. When observing gaze data from play, teachers explained the high amount of gaze by citing children’s particular needs. When observing gaze data from guided activities, teachers reflected on children’s unpredictable behavior and noted that the children’s need for support in concentration was linked to more gazes by the teacher. The findings showed that both during play and guided activities, children seeking a gaze and the position of children in the classroom influenced the number of teachers’ gazes. In the teachers’ explanations of their visual gaze and related pedagogical actions, five categories were identified: protection; physical and emotional availability, teaching and learning; facilitation; and initiatives. This explorative study showed that teachers utilize their knowledge concerning children’s individuality, development, and learning when they explain their decisions concerning their visual gaze and pedagogical activities with toddlers. The use of mobile eye-tracking technology is relatively new; therefore, its applications to ECEC are pioneering for the development of the field in relation to the practices and research of toddlers’ groups and groups with older children in ECEC

Substructures of the Weyl group and their physical applications

We study substructures of the Weyl group of conformal transformations of the metric of (pseudo)Riemannian manifolds. These substructures are identified by differential constraints on the conformal factors of the transformations which are chosen such that their composition is associative. Mathematically, apart from rare exceptions, they are partial associative groupoids, not groups, so they do not have an algebra of infinitesimal transformations, but this limitation can be partially circumvented using some of their properties cleverly. We classify and discuss the substructures with two-derivatives differential constraints, the most famous of which being known as the harmonic or restricted Weyl group in the physics literature, but we also show the existence of a lightcone constraint which realizes a proper subgroup of the Weyl group. We then show the physical implications that come from invariance under the two most important substructures, concentrating on classical properties of the energy-momentum tensor and a generalization of the quantum trace anomaly. We also elaborate further on the harmonic substructure, which can be interpreted as partial gauge fixing of full Weyl invariance using BRST methods. Finally, we discuss how to construct differential constraints of arbitrary higher-derivative order and present, as examples, generalizations involving scalar constraints with four and six derivatives.

Strengthening person-centered care through quality improvement: a mixed-methods study examining implementation of the Person-Centered Care Assessment Tool in Zambian health facilities

Introduction Person-centered care (PCC) is considered a fundamental approach to address clients’ needs. There is a dearth of data on specific actions that HIV treatment providers identify as priorities to strengthen PCC. Objective This study team developed the Person-Centered Care Assessment Tool (PCC-AT), which measures PCC service delivery within HIV treatment settings. The PCC-AT, including subsequent group action planning, was implemented across 29 facilities in Zambia among 173 HIV treatment providers. Mixed-methods study objectives included: (1) identify types of PCC-strengthening activities prioritized based upon low and high PCC-AT scores; (2) identify common themes in PCC implementation challenges and action plan activities by low and high PCC-AT score; and (3) determine differences in priority actions by facility ART clinic volume or geographic type. Methods The study team conducted thematic analysis of action plan data and cross-tabulation queries to observe patterns across themes, PCC-AT scores, and key study variables. Results The qualitative analysis identified 39 themes across 29 action plans. A higher proportion of rural compared to urban facilities identified actions related to stigma and clients’ rights training; accessibility of educational materials and gender-based violence training. A higher proportion of urban and peri-urban compared to rural facilities identified actions related to community-led monitoring. Discussion Findings provide a basis to understand common PCC weaknesses and activities providers perceive as opportunities to strengthen experiences in care. Conclusion To effectively support clients across the care continuum, systematic assessment of PCC services, action planning, continuous quality improvement interventions and re-measurements may be an important approach.

Anaerobic recovery of vivianite from waste-activated sludge through combined sludge pre-fermentation and agroforestry biomass-based biochar

The recovery of vivianite through the anaerobic digestion of waste-activated sludge has attracted considerable attention due to its operational simplicity and the high economic value of vivianite. This study concentrated on the recovery of vivianite from anaerobic fermentation systems through a strategy combining sludge pre-fermentation with the waste agricultural and forestry biomass-derived biochar (ZBC). In-depth analyses of the structure and functionality of ZBC were conducted using techniques such as Fourier-transform infrared spectroscopy (FTIR), X-ray photoelectron spectroscopy (XPS), and Raman spectroscopy. The sediment produced after the experiment and the changes in microbial community composition were characterized. The results indicated that pre-fermentation promoted phosphorus release, enhancing the synthesis of vivianite while selectively enriching respiratory and fermentative Fe (III)-reducing microorganisms. When FeOOH was used as the Fe (III) source, ZBC, through its dual action of redox functional groups and graphitization structure, increased the Fe2+ production by 243.6 % in the system dominated by respiratory Fe (III)-reducing bacteria. The optimal dosage of ZBC for the simultaneous recovery of vivianite resources and methane energy was 2.5 g/L. The combined application of pre-fermentation and ZBC provides a novel approach for the efficient recycling of vivianite and offers new insights into the reuse of agroforestry waste biomass resources.

Finite group actions on abelian groups of finite Morley rank

Finite group actions on abelian groups of finite Morley rank

CSI-Otter: isogeny-based (partially) blind signatures from the class group action with a twist

AbstractIn this paper, we construct the first provably-secure isogeny-based (partially) blind signature scheme. While at a high level the scheme resembles the Schnorr blind signature, our work does not directly follow from that construction, since isogenies do not offer as rich an algebraic structure. Specifically, our protocol does not fit into the linear identification protocol abstraction introduced by Hauck, Kiltz, and Loss (EUROCYRPT’19), which was used to generically construct Schnorr-like blind signatures based on modules such as classical groups and lattices. Consequently, our scheme is provably secure in the random oracle model (ROM) against poly-logarithmically-many concurrent sessions assuming the subexponential hardness of the group action inverse problem. In more detail, our blind signature exploits the quadratic twist of an elliptic curve in an essential way to endow isogenies with a strictly richer structure than abstract group actions (but still more restrictive than modules). The basic scheme has public key size 128 B and signature size 8 KB under the CSIDH-512 parameter sets—these are the smallest among all provably secure post-quantum secure blind signatures. Relying on a new ring variant of the group action inverse problem ($$\textsf{rGAIP}$$ rGAIP ), we can halve the signature size to 4 KB while increasing the public key size to 512 B. We provide preliminary cryptanalysis of $${\textsf{rGAIP}} $$ rGAIP and show that for certain parameter settings, it is essentially as secure as the standard $$\textsf{GAIP}$$ GAIP . Finally, we show a novel way to turn our blind signature into a partially blind signature, where we deviate from prior methods since they require hashing into the set of public keys while hiding the corresponding secret key—constructing such a hash function in the isogeny setting remains an open problem.

Research on the Motivation and Effect of Longfor Group's Transformation to Asset-light Operation Mode

Since the real estate marketization reform in 1998, China's real estate industry has continued to focus on asset operation mode, at that time in the golden period of the industry, real estate enterprises only need to hoard a lot of land, wait for the appreciation of the land and then resell, you can get considerable returns. However, in the context of the current slowdown in the economic growth of China's real estate industry, it is difficult for commercial real estate enterprises to continue to operate with heavy assets, so such enterprises begin to seek transformation, and want to change a profit model to match the current market. As a new way for enterprises to accumulate core competence and maximize value, "asset-light operation" model has been highly valued by the academic and business circles. This paper takes Longfor Group, a representative real estate enterprise, as the research object, and makes an in-depth analysis of the company's finance from the perspective of its financial characteristics and financial performance, in order to provide certain theoretical references for the successful application of the transformation and development of similar companies.

Mutations of numerically exceptional collections on surfaces

A conjecture of Bondal–Polishchuk states that, in particular for the bounded derived category of coherent sheaves on a smooth projective variety, the action of the braid group on full exceptional collections is transitive up to shifts. We show that the braid group acts transitively on the set of maximal numerically exceptional collections on rational surfaces up to isometries of the Picard lattice and twists with line bundles. Considering the blow-up of the projective plane in up to 9 points in very general position, these results lift to the derived category. More precisely, we prove that, under these assumptions, a maximal numerically exceptional collection consisting of line bundles is a full exceptional collection and any two of them are related by a sequence of mutations and shifts. The former extends a result of Elagin–Lunts and the latter a result of Kuleshov–Orlov, both concerning del Pezzo surfaces. In contrast, we show in concomitant work (Krah in Invent Math 235(3):1009–1018, 2024) that the blow-up of the projective plane in 10 points in general position admits a non-full exceptional collection of maximal length consisting of line bundles.

Dynamics of the epidemiological Predator-Prey system in advective environments.

This paper aims to establish the existence of traveling wave solutions connecting different equilibria for a spatial eco-epidemiological predator-prey system in advective environments. After applying the traveling wave coordinates, these solutions correspond to heteroclinic orbits in phase space. We investigate the existence of the traveling wave solution connecting from a boundary equilibrium to a co-existence equilibrium by using a shooting method. Different from the techniques introduced by Huang, we directly prove the convergence of the solution to a co-existence equilibrium by constructing a special bounded set. Furthermore, the Lyapunov-type function we constructed does not need the condition of bounded below. Our approach provides a different way to study the existence of traveling wave solutions about the co-existence equilibrium. The existence of traveling wave solutions between co-existence equilibria are proved by utilizing the qualitative theory and the geometric singular perturbation theory. Some other open questions of interest are also discussed in the paper.

Strategies to Obtain Reliable Energy Landscapes from Embedded Multireference Correlated Wavefunction Methods for Surface Reactions.

Embedded correlated wavefunction (ECW) theory is a powerful tool for studying ground- and excited-state reaction mechanisms and associated energetics in heterogeneous catalysis. Several factors are important to obtaining reliable ECW energies, critically the construction of consistent active spaces (ASs) along reaction pathways when using a multireference correlated wavefunction (CW) method that relies on a subset of orbital spaces in the configuration interaction expansion to account for static electron correlation, e.g., complete AS self-consistent field theory, in addition to the adequate partitioning of the system into a cluster and environment, as well as the choice of a suitable basis set and number of states included in excited-state simulations. Here, we conducted a series of systematic studies to develop best-practice guidelines for ground- and excited-state ECW theory simulations, utilizing the decomposition of NH3 on Pd(111) as an example. We determine that ECW theory results are relatively insensitive to cluster size, the aug-cc-pVDZ basis set provides an adequate compromise between computational complexity and accuracy, and that a fixed-clean-surface approximation holds well for the derivation of the embedding potential. Additionally, we demonstrate that a merging approach, which involves generating ASs from the molecular fragments at each configuration, is preferable to a creeping approach, which utilizes ASs from adjacent structures as an initial guess, for the generation of consistent potential energy curves involving open-d-shell metal surfaces, and, finally, we show that it is essential to include bands of excited states in their entirety when simulating excited-state reaction pathways.

Finitistic spaces with the orbit space 𝔽ℙn × 𝕊m

Let [Formula: see text], [Formula: see text] or [Formula: see text], act freely on a finitistic connected space [Formula: see text]. This paper gives the cohomology classification of [Formula: see text] if the mod 2 or rational cohomology of the orbit space [Formula: see text] is isomorphic to the product of a projective space and sphere [Formula: see text], where [Formula: see text] or [Formula: see text], respectively. For a free involution on [Formula: see text], a lower bound of covering dimension of the coincidence set of a continuous map [Formula: see text] is also determined.