Results 91 to 100 of about 157,174 (281)

Features of the partition function of a Λ > 0 universe

open access: yesJournal of High Energy Physics
We consider properties of the gravitational path integral, $${\mathcal{Z}}_{\text{grav}}$$ , of a four-dimensional gravitational effective field theory with Λ > 0 at the quantum level.
Dionysios Anninos   +3 more
doaj   +1 more source

On the Weyl anomaly of 4D conformal higher spins: a holographic approach

open access: yesJournal of High Energy Physics, 2017
We present a first attempt to derive the full (type-A and type-B) Weyl anomaly of four dimensional conformal higher spin (CHS) fields in a holographic way.
S. Acevedo   +3 more
doaj   +1 more source

Photon‐Sphere Modes in Curved Optical Microcavities: A Black‐Hole Analogue Laser

open access: yesAdvanced Science, EarlyView.
An optical analogue of a Schwarzschild black hole is realized using curved microcavities that preserve light‐like geodesics. A new family of laser modes confined around the photon sphere is identified alongside conventional whispering‐gallery modes. Analytical theory, numerical simulations, and experiments reveal curvature‐induced confinement, enabling
Chenni Xu   +9 more
wiley   +1 more source

Einstein Gravity, Lagrange-Finsler Geometry, and Nonsymmetric Metrics

open access: yesSymmetry, Integrability and Geometry: Methods and Applications, 2008
We formulate an approach to the geometry of Riemann-Cartan spaces provided with nonholonomic distributions defined by generic off-diagonal and nonsymmetric metrics inducing effective nonlinear and affine connections.
Sergiu I. Vacaru
doaj   +1 more source

A Bottom‐Up Design Framework for Multifunctional Lattice Metamaterials

open access: yesAdvanced Science, EarlyView.
This study introduces a generative AI framework for designing multifunctional lattice metamaterials. The method combines 3D Gaussian voxel generation with deep learning, enabling greater design freedom and structural performance. The optimized lattice metamaterials achieve enhanced energy absorption by 40–200% compared to conventional structures and ...
Zongxin Hu   +13 more
wiley   +1 more source

Four-Manifolds without Einstein Metrics [PDF]

open access: yesMathematical Research Letters, 1996
A smooth Riemannian metric \(g\) is said to be Einstein if its Ricci curvature \(r\) is a constant multiple of the metric, i.e. \(r=\lambda g\). It is known that not every compact oriented 4-manifold \(M\) admits such metrics. A necessary condition for the existence of an Einstein metric on \(M\) is that the Hitchin-Thorpe inequality \(2\chi(M)\geq 3 ...
openaire   +2 more sources

Nanoscale Spatial Organization of ARC High‐ and Low‐Order Assemblies at Excitatory Synapses

open access: yesAdvanced Science, EarlyView.
ARC (Activity‐Regulated Cytoskeleton‐Associated protein) mediates synaptic plasticity by forming nanoscale assemblies in neurons. Using super‐resolution microscopy and time‐resolved anisotropy with targeted tagging, the study reveals low‐order ARC assemblies at synapses colocalizing with AMPARs, semi‐circular structures at endocytic zones, and 60–80 nm
Martina Damenti   +13 more
wiley   +1 more source

Einstein Metrics on solvable groups

open access: yesMathematische Zeitschrift, 1991
We investigate when solvable Lie groups of a certain type do admit left invariant metrics with constant negative Ricci curvature. Our methods permit to construct a lot of new Einstein manifolds; some examples also have nonpositive sectional curvature.
openaire   +1 more source

Lymphoid‐Tissue‐on‐Chip Recapitulates Human Antibody Responses In Vitro

open access: yesAdvanced Science, EarlyView.
The presented lymphoid‐tissue‐on‐chip system allows culture of primary human tonsil cells at organotypic high density under perfusion for up to 4 weeks, emulates immune response to soluble vaccines and vaccination via peripheral antigen‐presenting cells and represents a useful tool to assess cellular interactions during homeostasis, immune responses ...
Claudia Teufel   +15 more
wiley   +1 more source

Carboranyl‐Curcuminoids for the Neutron Capture‐Based Treatment of Amyloid Aggregates in Alzheimer's Disease

open access: yesAdvanced Science, EarlyView.
The 10B‐enriched monocarbonyl analog of curcumin (BMAC) 10B‐9 enables site‐specific Boron Neutron Capture Therapy (BNCT) on amyloid‐β (Aβ) fibrils. Neutron irradiation induces histidine oxidation and fibril destabilization, as revealed by 1H‐NMR and FESEM analyses.
Sebastiano Micocci   +12 more
wiley   +1 more source

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