908 research outputs found
Topological Complexity of Frictional Interfaces: Friction Networks
Through research conducted in this study, a network approach to the
correlation patterns of void spaces in rough fractures (crack type II) was
developed. We characterized friction networks with several networks
characteristics. The correlation among network properties with the fracture
permeability is the result of friction networks. The revealed hubs in the
complex aperture networks confirmed the importance of highly correlated groups
to conduct the highlighted features of the dynamical aperture field. We found
that there is a universal power law between the nodes' degree and motifs
frequency (for triangles it reads T(k)\proptok{\beta} ({\beta}
\approx2\pm0.3)). The investigation of localization effects on eigenvectors
shows a remarkable difference in parallel and perpendicular aperture patches.
Furthermore, we estimate the rate of stored energy in asperities so that we
found that the rate of radiated energy is higher in parallel friction networks
than it is in transverse directions. The final part of our research highlights
4 point sub-graph distribution and its correlation with fluid flow. For shear
rupture, we observed a similar trend in sub-graph distribution, resulting from
parallel and transversal aperture profiles (a superfamily phenomenon)
Network-Configurations of Dynamic Friction Patterns
The complex configurations of dynamic friction patterns-regarding real time
contact areas- are transformed into appropriate networks. With this
transformation of a system to network space, many properties can be inferred
about the structure and dynamics of the system. Here, we analyze the dynamics
of static friction, i.e. nucleation processes, with respect to "friction
networks". We show that networks can successfully capture the crack-like shear
ruptures and possible corresponding acoustic features. We found that the
fraction of triangles remarkably scales with the detachment fronts. There is a
universal power law between nodes' degree and motifs frequency (for triangles,
it reads T(k)\proptok{\beta} ({\beta} \approx2\pm0.4)). We confirmed the
obtained universality in aperture-based friction networks. Based on the
achieved results, we extracted a possible friction law in terms of network
parameters and compared it with the rate and state friction laws. In
particular, the evolutions of loops are scaled with power law, indicating the
aggregation of cycles around hub nodes. Also, the transition to slow rupture is
scaled with the fast variation of local heterogeneity. Furthermore, the motif
distributions and modularity space of networks -in terms of withinmodule degree
and participation coefficient-show non-uniform general trends, indicating a
universal aspect of energy flow in shear ruptures
Tsallis holographic dark energy in the Brans-Dicke cosmology
Using the Tsallis generalized entropy, holographic hypothesis and also
considering the Hubble horizon as the IR cutoff, we build a holographic model
for dark energy and study its cosmological consequences in the Brans-Dicke
framework. At first, we focus on a non-interacting universe, and thereinafter,
we study the results of considering a sign-changeable interaction between the
dark sectors of the cosmos. Our investigations show that, compared with the
flat case, the power and freedom of the model in describing the cosmic
evolution is significantly increased in the presence of the curvature. The
stability analysis also indicates that, independent of the universe curvature,
both the interacting and non-interacting cases are classically unstable. In
fact, both the classical stability criterion and an acceptable behavior for the
cosmos quantities, including the deceleration and density parameters as well as
the equation of state, are not simultaneously obtainable.Comment: Accepted version, Eur. Phys. J. C (2018
The transcription factors Egr2 and Egr3 are essential for the control of inflammation and antigen-induced proliferation of B and T cells
This article is available open access under a Creative Commons license (http://creativecommons.org/licenses/by-nc-nd/3.0/). Copyright @ 2012 Elsevier Inc.Lymphocytes provide optimal responses against pathogens with minimal inflammatory pathology. However, the intrinsic mechanisms regulating these responses are unknown. Here, we report that deletion of both transcription factors Egr2 and Egr3 in lymphocytes resulted in a lethal autoimmune syndrome with excessive serum proinflammatory cytokines but also impaired antigen receptor-induced proliferation of B and T cells. Egr2- and Egr3-defective B and T cells had hyperactive signal transducer and activator of transcription-1 (STAT1) and STAT3 while antigen receptor-induced activation of transcription factor AP-1 was severely impaired. We discovered that Egr2 and/or Egr3 directly induced expression of suppressor of cytokine signaling-1 (SOCS1) and SOCS3, inhibitors of STAT1 and STAT3, and also blocked the function of Batf, an AP-1 inhibitor, in B and T cells. Thus, Egr2 and Egr3 regulate B and T cell function in adaptive immune responses and homeostasis by promoting antigen receptor signaling and controlling inflammation.Arthritis Research U
Functional-Friction Networks: New Insights on the Laboratory Earthquakes
We report some new applications of functional complex networks on acoustic
emission waveforms from frictional interfaces. Our results show that laboratory
faults undergo a sequence of generic phases as well as strengthening, weakening
or fast-slip and slow-slip leading to healing. Also, using functional networks,
we extend the dissipated energy due to acoustic emission signals in terms of
short-term and long-term features of events. We show that the transition from
regular to slow ruptures can have an additional production from the critical
rupture class similar to the direct observations of this phenomenon in the
transparent samples. Furthermore, we demonstrate detailed sub-micron evolution
of the interface due to the short-term evolution of rupture tip, which is
represented by phenomenological description of the modularity rates. In
addition, we found nucleation phase of each single event for most amplified
events follows a nearly constant time scale, corresponding to initial
strengthening of interfaces
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