Results 111 to 120 of about 3,675 (265)

Existence of periodic orbits for geodesible vector fields on closed 3-manifolds [PDF]

open access: yesErgodic Theory and Dynamical Systems, 2009
AbstractIn this paper we deal with the existence of periodic orbits of geodesible vector fields on closed 3-manifolds. A vector field is geodesible if there exists a Riemannian metric on the ambient manifold making its orbits geodesics. In particular, Reeb vector fields and vector fields that admit a global section are geodesible.
openaire   +3 more sources

Recognition of fossil keratose sponges in carbonates using petrographic and machine‐learning classification

open access: yesSedimentology, EarlyView.
ABSTRACT Filamentous, anastomosing spar‐filled networks in Phanerozoic carbonates have been interpreted as the mineralised remains of keratose (non‐spiculate) sponges, yet their recognition remains contested because fabrics of broadly similar appearance may arise from microbial, diagenetic or physical processes. This study combines direct fossil–modern
Jeong‐Hyun Lee   +2 more
wiley   +1 more source

Image and Volume Segmentation by Water Flow

open access: yes, 2007
A general framework for image segmentation is presented in this paper, based on the paradigm of water flow. The major water flow attributes like water pressure, surface tension and capillary force are defined in the context of force field generation and ...
Liu, Xin U., Nixon, Mark S.
core  

Symmetry and pseudosymmetry properties with Ricci soliton of the Reissner-Nordström-de Sitter spacetime

open access: yesNuclear Physics B
The primary objective of the article is to investigate the symmetry and pseudosymmetry properties of the Reissner-Nordström-de Sitter (briefly, RNdS) spacetime. The secondary aim of the paper is to explore the notion of Ricci solitons in RNdS spacetimes.
Absos Ali Shaikh, Kamiruzzaman
doaj   +1 more source

Physiological cerebrospinal fluid interactions between brain and eye structures are altered after long‐duration spaceflight

open access: yesExperimental Physiology, EarlyView.
Abstract Long‐duration spaceflight represents an extreme challenge, triggering adaptive responses including spaceflight‐associated neuro‐ocular syndrome, characterized by diminished visual acuity and ocular changes, which is a significant health risk for Mars missions.
Ge Tang   +19 more
wiley   +1 more source

Orthogonal geodesic and minimal distributions

open access: yes, 1983
Let F \mathfrak {F} be a smooth distribution on a Riemannian manifold M M with H \mathfrak {H} the orthogonal distribution. We say that F \mathfrak {F}
Irl Bivens
core   +1 more source

Unveiling sex dimorphism in the healthy cardiac anatomy: Fundamental differences between male and female heart shapes

open access: yesThe Journal of Physiology, EarlyView.
Abstract figure legend We present a shape modelling‐based morphological analysis of sex differences in cardiac anatomy. We conduct our analysis on 456 healthy subjects from the UK Biobank (227M/229F) to uncover sex‐based differences in healthy cardiac morphology.
Beatrice Moscoloni   +4 more
wiley   +1 more source

Invariant Measure and Universality of the 2D Yang–Mills Langevin Dynamic

open access: yesCommunications on Pure and Applied Mathematics, Volume 79, Issue 8, Page 1973-2102, August 2026.
ABSTRACT We prove that the Yang–Mills (YM) measure for the trivial principal bundle over the two‐dimensional torus, with any connected, compact structure group, is invariant for the associated renormalised Langevin dynamic. Our argument relies on a combination of regularity structures, lattice gauge‐fixing and Bourgain's method for invariant measures ...
Ilya Chevyrev, Hao Shen
wiley   +1 more source

Symmetries which preserve the characteristic vector field of K-contact manifolds

open access: yes, 1993
As is well-known locally symmetric K-contact manifolds are spaces of constant curvature ([13]).This means that having isometric local geodesic symmetries is a very strong restriction for K-contact manifolds.Thus other classes of isometries shall fit for ...
Sekizawa, Masami, Inoguti, Jun Iti
core   +1 more source

Computational study of permeability in cardboard coating layers

open access: yesAIChE Journal, Volume 72, Issue 7, July 2026.
Abstract We develop a virtual material structure model based on a combination of tessellations and Gaussian random fields for a coating layer of paperboard used for packaging and designed to facilitate printing on the surface. To fit the model to tomographic image data acquired using combined focused ion beam and scanning electron microscopy (FIB‐SEM),
Sandra Barman   +6 more
wiley   +1 more source

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