Article
Mathematics
Miroslava Antic, Djordje Kocic
Summary: This paper studies the parallelism of the structure Jacobi operator of real hypersurfaces in the nearly Kahler sphere S-6(1), and proves that such real hypersurfaces do not exist.
Article
Physics, Multidisciplinary
Andres Felipe Estupinan Salamanca, Sergio Bravo Medina, Marek Nowakowski, Davide Batic
Summary: This paper explores several non-flat universe models, including the standard cosmological scenario, Einstein-Cartan cosmology, Milne-McCrea universe with quantum corrections, and a non-flat universe with bulk viscosity. By employing various techniques, the study delves into the initial cosmological singularity, revealing the existence of nonsingular universes, such as the possibility of a static, non-expanding and stable Einstein universe.
Article
Physics, Particles & Fields
Damianos Iosifidis, Ioannis Georgios Vogiatzis, Christos G. G. Tsagas
Summary: We investigate the potential effects of spacetime non-metricity in cosmology by replacing torsion with non-metricity in the Einstein-Cartan gravity framework. By considering hyperfluid models and introducing non-vanishing hypermomentum to source spacetime non-metricity, we derive the field equations and conservation laws. Applying our findings to cosmology, we generalize the Friedmann and Raychaudhuri equations in the presence of non-metricity, discovering that non-metricity can mimic unconventional matter with different equation of state and may have played a significant role in the early universe's evolution.
EUROPEAN PHYSICAL JOURNAL C
(2023)
Article
Physics, Mathematical
Laszlo Kozma, Salah G. Elgendi
Summary: In this paper, we study the existence of parallel one forms (or parallel vector fields) on Riemannian manifolds using Finslerian settings. We prove that a parallel one form on a Riemannian manifold is a holonomy invariant function on the tangent bundle TM with respect to the geodesic spray. We investigate the conditions for the existence of a parallel one form on Riemannian and Finsler manifolds, and show that the metrizability freedom affects the existence of proper affine Killing vector fields.
INTERNATIONAL JOURNAL OF GEOMETRIC METHODS IN MODERN PHYSICS
(2023)
Article
Chemistry, Inorganic & Nuclear
Daniel Blasco, Felix Reboiro, Dage Sundholm, M. Elena Olmos, Miguel Monge, Jose M. Lopez-de-Luzuriaga
Summary: The existence of aurophilic gold(iii)-gold(iii) interactions has been overlooked due to structural arguments and comparison with gold(i) compounds. However, using CCSD(T) calculations, we demonstrate that the [Au-III(CH3)(3)(NH3)](2) dimer exhibits a metallophilic dispersion interaction between the gold(iii) atoms with an energy of 10.5 kJ mol(-1). The aurophilic interaction is confirmed by topological QTAIM calculations and IRI analysis.
DALTON TRANSACTIONS
(2023)
Article
Green & Sustainable Science & Technology
Daniel Holzer, Martin Popowicz, Romana Rauter, Kilian Silberschneider, Tobias Stern
Summary: The implementation of circular economy varies between bio-based and non-bio-based industries. The wood industry takes a more positive approach, while the plastic industry faces more barriers. Strategic interventions and policy adjustments are emphasized to address the challenges in each sector.
SUSTAINABLE PRODUCTION AND CONSUMPTION
(2023)
Article
Physics, Multidisciplinary
Rikpratik Sengupta, Bikash Ch Paul, Mehedi Kalam, Prasenjit Paul, Arkajit Aich
Summary: In this paper, the authors investigate an exotic matter source with a nonlinear equation of state and a minimally coupled scalar field with two different potentials that result in a closed inflationary emergent universe in a relativistic context. The study is conducted in the framework of Randall-Sundrum braneworld and effective Loop quantum cosmology, considering vanishing spatial curvature and no effective cosmological constant term. The results show that the initial singularity can be averted in almost all the cases, and the inflationary scenario is found to be improved compared to the standard relativistic context. The authors also discover bouncing and cyclic universes from their analysis in some cases, indicating the possibility of avoiding the initial singularity by appropriate mechanisms.
EUROPEAN PHYSICAL JOURNAL PLUS
(2023)
Article
Astronomy & Astrophysics
Boon Kiat Oh, John A. Peacock, Sadegh Khochfar, Britton D. Smith
Summary: This study compares the standard Lambda cold dark matter cosmology with counterfactual universes through simulations and explores the effects of Lambda and fluctuation amplitude on the evolution of the halo mass function, intergalactic medium, and star formation history. The results show that the peak and decline in star formation rate density are both influenced by the interplay between gravitational attraction and the accelerating effects of Lambda. The cooling of the intergalactic medium is faster in models with larger Lambda and lower sigma(8), resulting in reduced star formation rate density.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2022)
Article
Mathematics
Motoo Tange
Summary: Suppose X and X' are simply-connected closed exotic 4 manifolds. X' is obtained by an order 2 cork twist of X. An infinite family of exotic 4-manifolds not generated by any infinite order cork is given, providing the first example of such a condition. A necessary condition of 4-dimensional Ozsvath-Szabo invariants for a family to be generated by an infinite order cork is proven, and non-contractible relatively exotic 4-manifolds that are never induced by any cork are presented as an application. Furthermore, an estimate of the number of Ozsvath-Szabo invariants of 4-manifolds generated by a cork is provided.
ADVANCES IN MATHEMATICS
(2023)
Article
Mathematics, Applied
Qi Ding, J. Jost, Y. L. Xin
Summary: This study tackles the Dirichlet problem for minimal surface systems in various dimensions and codimensions through mean curvature flow, establishing the existence of minimal graphs over arbitrary mean convex bounded C2 domains with certain prescribed boundary data. It serves as a natural extension of the classical sharp criterion for solvability of the minimal surface equation by Jenkins-Serrin. However, a class of prescribed boundary data on mean convex domains was identified where the Dirichlet problem in codimension 2 remains unsolvable. Additionally, the study delves into the existence and uniqueness of minimal graphs through perturbation.
JOURNAL DE MATHEMATIQUES PURES ET APPLIQUEES
(2023)
Article
Chemistry, Multidisciplinary
Alyah F. Chmiel, Oliver P. Williams, Colleen P. Chernowsky, Charles S. Yeung, Zachary K. Wickens
Summary: This photocatalytic system utilizes radical anion intermediates to enhance photoreductant activity, enabling diverse aryl radical coupling reactions. Mechanistic studies reveal two parallel pathways for substrate reduction, both facilitated by the key terminal reductant byproduct, carbon dioxide radical anion.
JOURNAL OF THE AMERICAN CHEMICAL SOCIETY
(2021)
Article
History & Philosophy Of Science
Friedrich Christoph Dorge, Matthias Holweger
Summary: The paper discusses the existence of institutional facts (IFF), arguing that they are actually just well-established illusions and do not truly exist. The authors use six criteria to analyze the existence of IFF, finding that none of them support the existence of IFF. The paper also introduces a variant of the "Thomas Theorem" to refute the argument that denying the existence of IFF leaves an explanatory gap.
Article
Biochemistry & Molecular Biology
Grigorios Koulouras, Martin C. Frith
Summary: The study reveals significant absent oligomers using Markov models and suggests their absence is due to negative selection. Common significant MAWs are often mono- or dinucleotide tracts. MAWs in mammal genomes are often present but rare in other mammals, while human MAWs are frequently present in prokaryotes but rarely in human viruses.
NUCLEIC ACIDS RESEARCH
(2021)
Article
Engineering, Mechanical
Theresa E. Honein, Oliver M. O'Reilly
Summary: By constructing a single representative particle constrained to move on a configuration manifold, the relationships and equivalences between different formulations of the equations of motion can be explored and explained through several helpful geometric interpretations.
NONLINEAR DYNAMICS
(2021)
Article
Mathematics, Applied
Takehiko Gappo, Grigor Sargsyan
Summary: We prove that in a self-iterable universe, if kappa is an inaccessible limit of Woodin cardinal, then AD(R) + Theta holds in the derived model at kappa. The proof is fine-structure free and only requires basic knowledge of iteration trees and iteration strategies. Our proof can be seen as a fine structure free version of the well-known fact that AD(R) + Theta is true in the derived models of hod mice with inaccessible limit of Woodin cardinals (see for example Sargsyan [Mem. Amer. Math. Soc. 236 (2015), p. viii+172]). However, the proof uses different ideas and is more general.
PROCEEDINGS OF THE AMERICAN MATHEMATICAL SOCIETY
(2022)