495 research outputs found
Cosmological model with local symmetry of very special relativity and constraints on it from supernovae
Based on Cohen \& Glashow's very special relativity [A. G. Cohen and S. L.
Glashow, Phys. Rev. Lett. {\bf 97} (2006) 021601], we propose an anisotropic
modification to the Friedmann-Robertson-Walker (FRW) line element. An
arbitrarily oriented 1-form is introduced and the FRW spacetime becomes of the
Randers-Finsler type. The 1-form picks out a privileged axis in the universe.
Thus, the cosmological redshift as well as the Hubble diagram of the type Ia
supernovae (SNe Ia) becomes anisotropic. By directly analyzing the Union2
compilation, we obtain the privileged axis pointing to
(). This privileged axis is close to those obtained by
comparing the best-fit Hubble diagrams in pairs of hemispheres. It should be
noticed that the result is consistent with isotropy at the level
since the anisotropic magnitude is .Comment: 13 pages, 2 figures. Published at EPJC(2013
Finslerian MOND versus the Strong Gravitational Lensing of the Early-type Galaxies
The gravitational lensing of Bullet Clusters and early-type galaxies pose
serious challenges on the validity of MOND. Recently, Finslerian MOND, a
generalization of MOND in the framework of Finsler gravity, has been proposed
to explain the mass discrepancy problem of Bullet Cluster 1E 0657\ 558. In this
paper, we check the validity of the Finslerian MOND in describing the strong
gravitational lensing of early-type galaxies. The investigation on ten strong
lenses of the CASTLES samples shows that there is no strong evidence for the
existence of dark matter.Comment: 11 pages, 2 figures, 2 table
Mass spectrometry analysis of the variants of histone H3 and H4 of soybean and their post-translational modifications
Abstract Background Histone modifications and histone variants are of importance in many biological processes. To understand the biological functions of the global dynamics of histone modifications and histone variants in higher plants, we elucidated the variants and post-translational modifications of histones in soybean, a legume plant with a much bigger genome than that of Arabidopsis thaliana. Results In soybean leaves, mono-, di- and tri-methylation at Lysine 4, Lysine 27 and Lysine 36, and acetylation at Lysine 14, 18 and 23 were detected in HISTONE H3. Lysine 27 was prone to being mono-methylated, while tri-methylation was predominant at Lysine 36. We also observed that Lysine 27 methylation and Lysine 36 methylation usually excluded each other in HISTONE H3. Although methylation at HISTONE H3 Lysine 79 was not reported in A. thaliana, mono- and di-methylated HISTONE H3 Lysine 79 were detected in soybean. Besides, acetylation at Lysine 8 and 12 of HISTONE H4 in soybean were identified. Using a combination of mass spectrometry and nano-liquid chromatography, two variants of HISTONE H3 were detected and their modifications were determined. They were different at positions of A31F41S87S90 (HISTONE variant H3.1) and T31Y41H87L90 (HISTONE variant H3.2), respectively. The methylation patterns in these two HISTONE H3 variants also exhibited differences. Lysine 4 and Lysine 36 methylation were only detected in HISTONE H3.2, suggesting that HISTONE variant H3.2 might be associated with actively transcribing genes. In addition, two variants of histone H4 (H4.1 and H4.2) were also detected, which were missing in other organisms. In the histone variant H4.1 and H4.2, the amino acid 60 was isoleucine and valine, respectively. Conclusion This work revealed several distinct variants of soybean histone and their modifications that were different from A. thaliana, thus providing important biological information toward further understanding of the histone modifications and their functional significance in higher plants.</p
Scalable protocol to mitigate crosstalk in universal quantum gates
High-fidelity universal quantum gates are widely acknowledged as essential
for scalable quantum computation. However, in solid-state quantum systems,
which hold promise as physical implementation platforms for quantum
computation, the inevitable crosstalk resulting from interqubit
interactions significantly impairs quantum operation performance. Here we
propose a scalable protocol to achieve -crosstalk mitigation in universal
quantum gates. This method converts the noisy Hamiltonian with crosstalk
into a framework that efficiently suppresses all -crosstalk effects,
leading to ideal target quantum operations. Specifically, we first analytically
derive the -crosstalk mitigation conditions and then apply them to enhance
the performance of target universal quantum gates. Moreover, numerical
simulations validate the effectiveness of -crosstalk mitigation when
multiple qubit gates operate concurrently. As a result, our protocol presents a
promising approach for implementing practical parallel quantum gates in
large-scale quantum computation scenarios
CODE: Coherence based decision boundaries for feature correspondence
A key challenge in feature correspondence is the difficulty in differentiating true and false matches at a local descriptor level. This forces adoption of strict similarity thresholds that discard many true matches. However, if analyzed at a global level, false matches are usually randomly scattered while true matches tend to be coherent (clustered around a few dominant motions), thus creating a coherence based separability constraint. This paper proposes a non-linear regression technique that can discover such a coherence based separability constraint from highly noisy matches and embed it into a correspondence likelihood model. Once computed, the model can filter the entire set of nearest neighbor matches (which typically contains over 90 percent false matches) for true matches. We integrate our technique into a full feature correspondence system which reliably generates large numbers of good quality correspondences over wide baselines where previous techniques provide few or no matches
Lusin-type approximation of Sobolev by Lipschitz functions, in Gaussian and spaces
We establish new approximation results, in the sense of Lusin, of Sobolev
functions by Lipschitz ones, in some classes of non-doubling metric measure
structures. Our proof technique relies upon estimates for heat semigroups and
applies to Gaussian and spaces. As a consequence, we obtain
quantitative stability for regular Lagrangian flows in Gaussian settings
2,2′-(Decane-1,10-diÂyl)dibenzÂimidÂazoÂlium dichloride trihydrate
The organic cation in the title compound, C24H32N4
2+·2Cl−·3H2O, is situated on an inversion centre. The cations, anions and water molÂecules are linked via N—H⋯O, N—H⋯Cl, O—H⋯O and O—H⋯Cl hydrogen bonds and C—H⋯π interactions, forming a three-dimensional framework
Chondroitin sulfate proteoglycans regulate the growth, differentiation and migration of multipotent neural precursor cells through the integrin signaling pathway
<p>Abstract</p> <p>Background</p> <p>Neural precursor cells (NPCs) are defined by their ability to proliferate, self-renew, and retain the potential to differentiate into neurons and glia. Deciphering the factors that regulate their behaviors will greatly aid in their use as potential therapeutic agents or targets. Chondroitin sulfate proteoglycans (CSPGs) are prominent components of the extracellular matrix (ECM) in the central nervous system (CNS) and are assumed to play important roles in controlling neuronal differentiation and development.</p> <p>Results</p> <p>In the present study, we demonstrated that CSPGs were constitutively expressed on the NPCs isolated from the E16 rat embryonic brain. When chondroitinase ABC was used to abolish the function of endogenous CSPGs on NPCs, it induced a series of biological responses including the proliferation, differentiation and migration of NPCs, indicating that CSPGs may play a critical role in NPC development and differentiation. Finally, we provided evidence suggesting that integrin signaling pathway may be involved in the effects of CSPGs on NPCs.</p> <p>Conclusion</p> <p>The present study investigating the influence and mechanisms of CSPGs on the differentiation and migration of NPCs should help us to understand the basic biology of NPCs during CNS development and provide new insights into developing new strategies for the treatment of the neurological disorders in the CNS.</p
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