2,574 research outputs found
Strange stars with different quark mass scalings
We investigate the stability of strange quark matter and the properties of
the corresponding strange stars, within a wide range of quark mass scaling. The
calculation shows that the resulting maximum mass always lies between 1.5 solor
mass and 1.8 solor mass for all the scalings chosen here. Strange star
sequences with a linear scaling would support less gravitational mass, and a
change (increase or decrease) of the scaling around the linear scaling would
lead to a larger maximum mass. Radii invariably decrease with the mass scaling.
Then the larger the scaling, the faster the star might spin. In addition, the
variation of the scaling would cause an order of magnitude change of the strong
electric field on quark surface, which is essential to support possible crusts
of strange stars against gravity and may then have some astrophysical
implications.Comment: 5 pages, 6 figures, 1 table. accepted by M
hSef potentiates EGF-mediated MAPK signaling through affecting EGFR trafficking and degradation
Sef (similar expression to fgf genes) was identified as an effective antagonist of fibroblast growth factor (FGF) in vertebrates. Previous reports have demonstrated that Sef interacts with FGF receptors (FGFRs) and inhibits FGF signaling, however, its role in regulating epidermal growth factor receptor (EGFR) signaling remains unclear. In this report, we found that hSef localizes to the plasma membrane (PM) and is subjected to rapid internalization and well localizes in early/recycling endosomes while poorly in late endosomes/lysosomes. We observed that hSef interacts and functionally colocalizes with EGFR in early endosomes in response to EGF stimulation. Importantly, we demonstrated that overexpression of hSef attenuates EGFR degradation and potentiates EGF-mediated mitogen-activated protein kinase (MAPK) signaling by interfering EGFR trafficking. Finally, our data showed that, with overexpression of hSef, elevated levels of Erk phosphorylation and differentiation of rat pheochromocytoma (PC12) cells occur in response to EGF stimulation. Taken together, these data suggest that hSef plays a positive role in the EGFR-mediated MAPK signaling pathway. This report, for the first time, reveals opposite roles for Sef in EGF and FGF signalings
Toward High Carrier Mobility and Low Contact Resistance: Laser Cleaning of PMMA Residues on Graphene Surfaces
Bridgeness: A Local Index on Edge Significance in Maintaining Global Connectivity
Edges in a network can be divided into two kinds according to their different
roles: some enhance the locality like the ones inside a cluster while others
contribute to the global connectivity like the ones connecting two clusters. A
recent study by Onnela et al uncovered the weak ties effects in mobile
communication. In this article, we provide complementary results on document
networks, that is, the edges connecting less similar nodes in content are more
significant in maintaining the global connectivity. We propose an index named
bridgeness to quantify the edge significance in maintaining connectivity, which
only depends on local information of network topology. We compare the
bridgeness with content similarity and some other structural indices according
to an edge percolation process. Experimental results on document networks show
that the bridgeness outperforms content similarity in characterizing the edge
significance. Furthermore, extensive numerical results on disparate networks
indicate that the bridgeness is also better than some well-known indices on
edge significance, including the Jaccard coefficient, degree product and
betweenness centrality.Comment: 10 pages, 4 figures, 1 tabl
Modeling the clustering in citation networks
For the study of citation networks, a challenging problem is modeling the
high clustering. Existing studies indicate that the promising way to model the
high clustering is a copying strategy, i.e., a paper copies the references of
its neighbour as its own references. However, the line of models highly
underestimates the number of abundant triangles observed in real citation
networks and thus cannot well model the high clustering. In this paper, we
point out that the failure of existing models lies in that they do not capture
the connecting patterns among existing papers. By leveraging the knowledge
indicated by such connecting patterns, we further propose a new model for the
high clustering in citation networks. Experiments on two real world citation
networks, respectively from a special research area and a multidisciplinary
research area, demonstrate that our model can reproduce not only the power-law
degree distribution as traditional models but also the number of triangles, the
high clustering coefficient and the size distribution of co-citation clusters
as observed in these real networks
A genome-wide association study identifies a genomic region for the polycerate phenotype in sheep (Ovis aries)
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Exploring Gravity via strongly lensed fast radio bursts
This study aims to investigate the strong gravitational lensing effects in
gravity. We present the theoretical analytic expressions for the lensing
effects in gravity, including deflection angle, magnification, and time
delay. On this basis, we also take the plasma lensing effect into
consideration. We compare the lensing effects between the General Relativity in
a vacuum environment and the gravity in a plasma environment. From a
strongly lensed fast radio burst, the results indicate that in a plasma
environment, General Relativity and gravity can generate
indistinguishable image positions, but the magnification and time delay on
these positions are significantly different, which can be distinguished by
current facilities in principle. Therefore, the discrepancies between
observational results and theoretical expectations can serve as clues for a
modified gravity theory and provide constraints on gravity
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