Action Of Group Research Articles

Predicting the Dominant Formation Mechanism of Multiplanetary Systems

Most, if not all, Sun-like stars host one or more planets, making multiplanetary systems commonplace in our Galaxy. We utilize hundreds of multiplanet simulations to explore the origin of such systems, focusing on their orbital architecture. The first set of simulations assumes in situ assembly of planetary embryos, while the second explores planetary migration. After applying observational biases to the simulations, we compare them to 250+ observed multiplanetary systems, including 13 systems with planets in the habitable zone. For all of the systems, we calculate two of the so-called statistical measures: the mass concentration (S c ) and orbital spacing (S s ). After analytic and empirical analyses, we find that the measures are related to first order with a power law: Sc∼Ssβ . The in situ systems exhibit steeper power-law relations relative to the migration systems. We show that different formation scenarios cover different regions in the S s –S c diagram with some overlap. Furthermore, we discover that observed systems with S s < 30 are likely dominated by the migration scenario, while those with S s ≥ 30 are likely dominated by the in situ scenario. We apply these criteria to determine that a majority (62%) of observed multiplanetary systems formed via migration, whereas most systems with currently observed habitable planets formed via in situ assembly. This work provides methods of leveraging the statistical measures (S s and S c ) to disentangle the formation history of observed multiplanetary systems based on their present-day architectures.

Probing elemental diffusion and radiation tolerance of perovskite solar cells via non-destructive Rutherford backscattering spectrometry

Mixed organic–inorganic halide perovskite-based solar cells have attracted interest in recent years due to their potential for both terrestrial and space applications. Analysis of interfaces is critical to predicting device behavior and optimizing device architectures. Most advanced tools to study buried interfaces are destructive in nature and can induce further degradation. Ion beam techniques, such as Rutherford backscattering spectrometry (RBS), is a useful non-destructive method to probe an elemental depth profile of multilayered perovskite solar cells (PSCs) as well as to study the inter-diffusion of various elemental species across interfaces. Additionally, PSCs are becoming viable candidates for space photovoltaic applications, and it is critical to investigate their radiation-induced degradation. RBS can be simultaneously utilized to analyze the radiation effects induced by He+ beam on the device, given their presence in space orbits. In the present work, a 2 MeV He+ beam was used to probe the evidence of elemental diffusion across PSC interfaces with architecture glass/ITO/SnO2/Cs0.05(MA0.17FA0.83)0.95Pb(I0.83Br0.17)3/spiro-OMeTAD/MoO3/Au. During the analysis, the device active area was exposed to an irradiation equivalent of up to 1.62 × 1015 He+/cm2, and yet, no measurable evidence (with a depth resolution ∼1 nm) of beam-induced ion migration was observed, implying high radiation tolerance of PSCs. On the other hand, aged PSCs exhibited indications of the movement of diverse elemental species, such as Au, Pb, In, Sn, Br, and I, in the active area of the device, which was quantified with the help of RBS.

Promising porous materials for uranium extraction from seawater

Uranium extraction from seawater is a promising approach for ensuring continued uranium fuel supply to the nuclear power industry. However, extracting uranium by this route is challenging due to the low concentration of uranium, high ionic strength, and marine micro-organisms in seawater. Recently, a range of novel porous adsorbent materials have been developed for uranium extraction from ocean water. These adsorbents rely on specific pore characteristics and functional groups (hydroxyl, carboxyl, amidoxime, phosphate, etc.) to achieve a high affinity and selectivity for uranyl ions (UO22+) relative to other ions. Relying strongly on coordination principles, specific binding sites for uranium are assembled in these porous materials, with cooperative actions of several functional groups often used to achieve strong uranium capture and adsorption selectivity. In addition to traditional adsorbents, adsorption-photocatalytic and adsorption-electrocatalytic materials are also being pursued, which include both specific adsorption sites and photocatalytic or electrocatalytic moieties in their frameworks. These innovative strategies allow the conversion of uranyl ions into harvestable solid products (such as UO2 or Na2O(UO3·H2O)x) and result in high extraction efficiencies together with good biofouling resistance. This perspective aims to capture some of the recent breakthroughs in the design of porous materials for selective uranium extraction from seawater.

The effects of self-other overlap and group efficacy on group-based anger and collective action tendency: An online experimental study

Collective emotions and actions represent foundational constructs in social psychology, significantly influencing societal dynamics and responses. Within this framework, the Self-Other Overlap (SOO) - wherein individuals perceive minimal distinction between their own and others' identities - has been identified as an impactful factor at the interpersonal level. However, the extrapolation of SOO's implications at the collective, group level remains an underexplored domain in contemporary research.In addressing this lacuna, the present research endeavors to elucidate the multifaceted implications of SOO on group emotions and actions, contextualized within societal challenges such as “food hygiene problems”. Utilizing validated instruments including the Self-Other Overlap Scale, Group-Based Anger Scale, Collective Action Tendency Scale, and Group Efficacy Scale for Coping Situations, this study adopts a tripartite situational experiment, engaging a collective sample of 359 participants, systematically recruited via the Credamo smart research platform to ensure representativeness.Study 1 examined the potential influence of variable SOO degrees on Group-Based Anger (GA) and Collective Action Tendency (CAT). Study 2 further refined the exploration, discerning the differential impacts of SOO targets on GA and CAT. Conclusively, Study 3 sought to ascertain the potential moderating role of Group Efficacy (GE) within the SOO-GA-CAT relationship.The empirical findings yielded several salient insights: notably, an augmentation in SOO levels corresponded with an amplification of GA and CAT. Furthermore, a delineation in SOO targets, specifically from external to ingroup entities, manifested in a pronounced augmentation of GA and CAT. Intriguingly, while elevated SOO predisposed heightened CAT, the modulatory effect of GE on CAT manifested predominantly in lower SOO contexts.In summation, the present study underscores the pivotal role of SOO magnitude and orientation as determinants of GA and CAT. The nuanced interplay between SOO degree and GE, particularly vis-à-vis CAT, provides a fresh scholarly perspective, contributing to the enriched understanding of group dynamics and collective behavioral paradigms.

Orbit spaces of free involutions on the product of three spheres

In this paper, we have determined the orbit spaces of free involutions on a finitistic space having mod 2 cohomology of the product of three spheres . This paper generalizes the results proved by Dotzel et al. [7] for free involutions on the product of two sphere . As an application, we have also derived the Borsuk-Ulam type results.

On fillings of contact links of quotient singularities

AbstractWe study several aspects of fillings for links of general isolated quotient singularities using Floer theory, including co‐fillings, Weinstein fillings, strong fillings, exact fillings and exact orbifold fillings, focusing on the non‐existence of exact fillings of contact links of isolated terminal quotient singularities. We provide an extensive list of isolated terminal quotient singularities whose contact links are not exactly fillable, including for , which settles a conjecture of Eliashberg, quotient singularities from general cyclic group actions and finite subgroups of , and all terminal quotient singularities in complex dimension 3. We also obtain uniqueness of the orbifold diffeomorphism type of exact orbifold fillings of contact links of some isolated terminal quotient singularities.

Intrinsic Ergodicity, Generators, and Symbolic Representations of Algebraic Group Actions

Intrinsic Ergodicity, Generators, and Symbolic Representations of Algebraic Group Actions

Symplectic complexity of reductive group actions

Let a complex algebraic reductive group G act on a complex algebraic manifold X. For a G-invariant subvariety Ξ of the nilpotent cone N(g∗)⊂g∗ we define a notion of Ξ-symplectic complexity of X. This notion generalizes the notion of complexity defined in Vinberg (1986). We prove several properties of this notion, and relate it to the notion of Ξ-complexity defined in Aizenbud and Gourevitch (2024) motivated by its relation with representation theory.

Exact solutions of Burgers equation with moving boundary

In this paper, new symmetry reductions and similarity solutions for Burgers equation with moving boundary are obtained by means of Lie’s method of infinitesimal transformation groups, for a linearly moving boundary as well as a parabolically moving boundary. By using discrete symmetries, new analytical solutions for the problem under consideration are presented, for two cases of the moving boundary: one moving with constant velocity and another one rapidly oscillating.

Graphs of schemes associated to group actions

Let $X$ be a proper algebraic scheme over an algebraically closed field. We assume that a torus $T$ acts on $X$ such that the action has isolated fixed points. The $T$-graph of $X$ can be defined using the fixed points and the one-dimensional orbits of the $T$-action. If the upper Borel subgroup of the general linear group with maximal torus $T$ acts on $X$, then we can define a second graph associated to $X$, called the $A$-graph of $X$. We prove that the $A$-graph of $X$ is connected if and only if $X$ is connected. We use this result to give proof of Hartshorne's theorem on the connectedness of the Hilbert scheme in the case of $d$ points in $\mathbb{P}^{n}$. .

Seeing is more than believing: Personal experience increases climate action.

Although global warming is a serious problem that influences numerous people worldwide, individuals are still reluctant to change their behaviours. The present research investigates how local hot temperatures affect climate action in non-Western groups. In Study 1, an analysis of temperature and information acquisition by Shanghai residents in 122 days found that heat increased attention and awareness of climate change. In Study 2 and Study 3, participants who were primed with heat-related perceptions were more likely to take climate action in private and public spheres. In Study 4, we further identified that people who experienced hot temperature events increased their beliefs and efficacy about climate change, which in turn motivated them to take more climate action. Importantly, the mediating effects were significant both in the manipulation of heat and real-world settings. Consistent with our theoretical perspective, seeing is more than believing because personal experience increases climate action by fostering climate change beliefs and efficacy.

Connecting space missions through NGSO constellations: feasibility study

A satellite internet provider (e.g., Starlink, OneWeb, O3b mPOWR), despite possessing the capability to provide internet services to on-ground users in a global scale, can dramatically change the way space missions are designed and operated in the foreseeable future. Assuming a scenario where space mission satellites can access the internet via a space internet system, the satellite can be connected to the network permanently (24 × 7) and act as mere terminal independently from its location. The ability to communicate with the satellite on-demand has the potential to improve aspects such as real-time tasking, outage minimization, operation cost, and dependency on the ground. This paper performs a feasibility study on the concept of connecting space missions to the network through commercial mega-constellations. This study includes a review of existing and near-future space internet systems, identification of candidate space missions for the aforementioned concept, a necessary adaptation of existing Commercial off-the-shelf (COTS) terminals to be plugged into space mission satellites, assessment of communication performance, and investigation of the legal aspects of the radio frequency (RF) spectrum usage. The paper evidences that the concept is practically possible to implement in the near future. Among the studied space internet systems (i.e., Starlink, OneWeb, O3b mPOWER), O3b mPOWER stands out as the most suitable system allowing permanent coverage of low earth orbit (LEO) space missions with data rates that can reach up to 21 Mbps per satellite. Although the concept is very promising and can be implemented in the near future, our investigations show that some regulatory aspects regarding the RF usage should be solved for future exploitation of connecting space missions through NGSO (Non-Geostationary Satellite Orbit) constellations.

Experimental and numerical investigation on the behavior of concrete sandwich slab panel for a structural system

This paper proposes a simplified methodology based on a concentrated plasticity model to develop numerical analysis of concrete sandwich slab panels for structural systems. Also, a proposal for the determination of experimental damage and its evolution within concrete sandwich panels is formulated. To validate the proposed methodology, an experimental study was carried out on full-scale slab panels to analyze the flexural behavior. Eight specimens were subjected to three- and four-point bending tests. A cycle loading protocol with unloading up to zero load was performed. These specimens, constructed with either one or two joined panels, were used to assess the group action. Mechanical properties for structural analysis—such as strength, stiffness, degree of composite action, and effective moment of inertia—were determined. The tested specimens exhibit significant stiffness degradation, indicating a notable evolution of damage even at small plastic displacements. The proposed methodology proves to be effective and reliable for predicting the behavior of concrete sandwich panels under bending moments. The numerical simulations performed show an adequate description of slab panel behavior until the ultimate load, regardless of its simplicity.

Operator Space Complexification Transfigured

Abstract Given a finite group $G$, a central subgroup $H$ of $G$, and an operator space $X$ equipped with an action of $H$ by complete isometries, we construct an operator space $X_{G}$ equipped with an action of $G$ that is unique under a “reasonable” condition. This generalizes the operator space complexification $X_{c}$ of $X$. As a linear space $X_{G}$ is the space obtained from inducing the representation of $H$ to $G$ (in the sense of Frobenius). Indeed a main achievement of our paper is the induced representation construction in the category of operator spaces. This has been hitherto elusive even for Banach spaces since it is not clear how to norm the induced space. We show that for a large class of group actions the induced space has a unique operator space norm.

The variational principle of topological r-pressure for amenable group actions

In this paper, we introduce the notions of the topological r-pressure and measure-theoretic r-pressure for countable discrete amenable group actions. In addition, we establish a variational principle between topological r-pressure and measure-theoretic r-pressure.

Matrix factorizations of the discriminant of Sn

Consider the symmetric group Sn acting as a reflection group on the polynomial ring k[x1,…,xn] where k is a field, such that Char(k) does not divide n!. We use Higher Specht polynomials to construct matrix factorizations of the discriminant of this group action: these matrix factorizations are indexed by partitions of n and respect the decomposition of the coinvariant algebra into isotypical components. The maximal Cohen–Macaulay modules associated to these matrix factorizations give rise to a noncommutative resolution of the discriminant and they correspond to the nontrivial irreducible representations of Sn. All our constructions are implemented in Macaulay2 and we provide several examples. We also discuss extensions of these results to Young subgroups of Sn and indicate how to generalize them to the reflection groups G(m,1,n).

Equivariant cohomology and deformation for algebras - an operadic approach

Let P be an operad with a multiplication, and later with a (higher) derivation. This paper introduces and develops a notion of (partial) group action and corresponding equivariant cohomology and deformation theory on P. It generalizes existing results for equivariant cohomology and deformation for associative algebras, dialgebras, and dendriform algebras, among others. At the end, we discuss compatibilities of group action and some operadic constructions.

Influence of structural properties on the suspension performance of ultra-high temperature stabilizers

One of the key challenges preventing the exploration and development of ultra-deep oil and gas deposits is the settlement instability of cement slurry at extremely high temperatures. In the previous work, an ultra-high temperature suspension stabilizer was created to enhance the cement slurry's high temperature settlement stability. This work investigates its mechanism from the standpoint of structural characteristics based on the prior research. Thermal stability tests and calculations of the pyrolysis activation energy were used to examine the structural features of the suspension stabilizer. The viscosity-temperature relationship, the microstructure of the suspension stabilizer solution, the molecular structure change of the suspension stabilizer in the solution environment, and the interaction energy with water molecules were all studied in conjunction with contemporary material testing techniques and molecular dynamics simulation calculations. The findings indicate that: 1) The bulk structure of the suspension stabilizer has a pyrolysis temperature of 330 °C, which indicates a degree of heat resistance; 2) In a solution environment, the viscosity of the solution is a critical factor in determining the stability of the cement slurry's sedimentation, which is dependent on the integrity of the amide group in the suspension stabilizer. The cyclic functional group's ortho action prevents the amide monomer from hydrolyzing in the ultra-high temperature suspension stabilizer. The cement slurry has good sedimentation stability because the hydrogen link between the retained amide group and the water molecule has not entirely broken down, and the solution still has some viscosity.

Dynamics of accelerating and decelerating flows: A boundary layer examination with non-similar approach and convective boundary condition

Moisture/air-flow over the aircraft wing and bonnet of a moving car in aerodynamical systems exhibit dynamic behavior characterized by accelerating and decelerating flows. These analysis is essential and applicable in various fields, including physics, engineering, and fluid mechanics. The present investigation aim to explore the dynamics of accelerating and decelerating flows within the framework of boundary layer examination. To achieve these objectives, a non-similar group of transformations is employed to convert the governing dimensional two-variable dynamical system into a dimensionless differential form, with η and ξ as the independent variables. To gain physical understanding of the mathematical equations governing the flow, an efficient bivariate spectral collocation method (BSCM) is employed for analyzing the flow dynamics. This method allows for a thorough investigation of the behavior and characteristics of the accelerating and decelerating Casson flows. Subject to the convergence and residual error analysis of the numerical results, the effects of pertinent parameters on the flow variables were investigated. The findings of this study show that the effects of flow parameters on decelerating and accelerating flows are not completely opposite. Additionally, the Biot parameter positively impacts the velocity and temperature profiles of the two dynamical flows. However, an increase in the Casson fluid parameter β has an opposing effect on the temperature and concentration profiles of both flows.

Properly outer and strictly outer actions of finite groups on prime C*-algebras

An action of a compact, in particular finite group on a C*-algebra is called properly outer if no automorphism of the group that is distinct from identity is implemented by a unitary element of the algebra of local multipliers of the C*-algebra. In this paper, I define the notion of strictly outer action (similar to the definition for von Neumann factors in [S. Vaes, The unitary implementation of a locally compact group action, J. Funct. Anal. 180 (2001) 426–480]) and prove that for finite groups and prime C*-algebras, it is equivalent to the proper outerness of the action. For finite abelian groups this is equivalent to other relevant properties of the action.