Results 91 to 100 of about 6,253,661 (292)

Weakly Ricci-Symmetric Space-Times and f (R,G) Gravity

Mathematics
In the present article, we classify conformally flat weakly Ricci-symmetric space-times and obtain that they represent Robertson–Walker space-times. Furthermore, we provethat a Ricci-recurrent weakly Ricci-symmetric space-time is static and a Ricci-semi ...
Yanlin Li, Uday Chand De, Krishnendu De
doaj   +1 more source

Energy conditions, traversable wormholes and dust shells

, 2004
Firstly, we review the pointwise and averaged energy conditions, the quantum inequality and the notion of the ``volume integral quantifier'', which provides a measure of the ``total amount'' of energy condition violating matter.
A. DeBenedictis, A. DeBenedictis, A. Everett, C. Barcelo, E. Poisson, E.F. Eiroa, E.G. Harris, F. Tipler, F.S.N. Lobo, F.S.N. Lobo, F.S.N. Lobo, Francisco S. N. Lobo, H.G. Ellis, J.P.S. Lemos, J.P.S. Lemos, L.H. Ford, L.H. Ford, L.H. Ford, L.H. Ford, M. Morris, M. Morris, M. Visser, M. Visser, M. Visser, M. Visser, M.J. Pfenning, S. Kar, S.W. Kim, S.W. Kim   +28 more
core   +1 more source

Derivation of the null energy condition

Physical Review D, 2015
We derive the null energy condition, understood as a constraint on the Einstein-frame Ricci tensor, from worldsheet string theory. For a closed bosonic string propagating in a curved geometry, the spacetime interpretation of the Virasoro constraint condition is precisely the null energy condition, to leading nontrivial order in the alpha-prime ...
Parikh, M., van der Schaar, J.P.
openaire   +5 more sources

The planar cell polarity protein Vangl2 interacts with the PDZ‐domains of Scribble but not with a unique PDZ‐like domain in Inturned

FEBS Letters, EarlyView.
Structural and biochemical characterisations show that the planar cell polarity (PCP) protein Inturned harbours a unique PDZ‐like domain that does not bind canonical PDZ‐binding motifs (PBMs) like that of another PCP protein Vangl2. In contrast, the apical‐basal polarity protein Scribble contains four PDZ domains that bind Vangl2, but one PDZ domain ...
Stephan Wilmes, Jan Brysch, Carmen Gelze, Lilli Meier, Daniel Kümmel   +4 more
wiley   +1 more source

Tau acetylation at K331 has limited impact on tau pathology in vivo

FEBS Letters, EarlyView.
We mapped tau post‐translational modifications in humanized MAPT knock‐in mice and in amyloid‐bearing double knock‐in mice. Acetylation within the repeat domain, particularly around K331, showed modest increases under amyloid pathology. To test functional relevance, we generated MAPTK331Q knock‐in mice.
Shoko Hashimoto, Yukio Matsuba, Mika Takahashi, Takaomi C. Saido   +3 more
wiley   +1 more source

A Tunable Plasmonic Refractive Index Sensor with Nanoring-Strip Graphene Arrays

Sensors, 2018
In the present study, we design a tunable plasmonic refractive index sensor with nanoring-strip graphene arrays. The calculations prove that the nanoring-strip have two transmission dips.
Chunlian Cen, Hang Lin, Jing Huang, Cuiping Liang, Xifang Chen, Yongjian Tang, Zao Yi, Xin Ye, Jiangwei Liu, Yougen Yi, Shuyuan Xiao   +10 more
doaj   +1 more source

Energy Conditions and Segre Classification of Phantom Fields

, 2005
Recent discoveries in the field of observational cosmology have provided increasing evidence that the Universe is undergoing a late time acceleration, which has also stimulated speculations on the nature of the dark component responsible for such a ...
Alcaniz, J. S., Santos, J.
core   +1 more source

Calpain small subunit homodimerization is robust and calcium‐independent

FEBS Letters, EarlyView.
Calpains dimerize via penta‐EF‐hand (PEF) domains. Using single‐molecule force spectroscopy, we measured the strength and kinetics of PEF–PEF homodimer binding. The interaction is robust, shows a transient conformational step before dissociation, and remains largely insensitive to Ca2+.
Nesha May O. Andoy, Trina Dykstra‐MacPherson, Mathias A. Bell, Peter L. Davies, Ruby May A. Sullan   +4 more
wiley   +1 more source

Energy-Efficient Air Conditioning

, 2016
Four countries in the Maghreb region of North Africa — Algeria, Libya, Morocco, and Tunisia are facing the common challenge of a rapid increase in energy demand, in particular for electricity, linked to population growth and rising standards of living.
Khalfallah, Ezzedine, Missaoui, Rafik, El Khamlichi, Samira, Ben Hassine, Hassen   +3 more
openaire   +3 more sources

Kaluza-Klein FRW Renyi Holographic Dark Energy model in Scalar-Tensor Theory of Gravitation

East European Journal of Physics
This work examines the dark energy phenomenon by studying the Renyi Holographic Dark Energy (RHDE) and pressure-less Dark Matter (DM) within the frame-work of Saez-Ballester (SB) scalar-tensor theory of gravitation(Phys. Lett. A113, 467:1986). To achieve
Y. Sobhanbabu, M. Vijaya Santhi, A. Srinivasa Rao, M. Praveen Kumar   +3 more
doaj   +1 more source