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Arbitrary flow boundary conditions in smoothed dissipative particle dynamics: A generalized virtual rheometer
Get PDFIn this work, a methodology to perform rheological studies on smoothed dissipative particle dynamics under arbitrary flow configurations is introduced. To evaluate the accuracy and flexibility of the proposed methodology, viscometric studies for Newtonian fluids under pure shear, pure extension, and arbitrary flows in bulk or near walls are introduced. The applicability of this methodology to obtain viscoelastic properties of non-Newtonian fluids, such as polymer solutions, is also presented. The new computational approach offers relevant advantages in a variety of applications ranging from multiscale simulations to the rheological characterization of complex flows
The Hajłasz capacity density condition is self-improving
Get PDFWe prove a self-improvement property of a capacity density condition for a nonlocal
Haj lasz gradient in complete geodesic spaces. The proof relates the capacity density condition
with boundary Poincar´e inequalities, adapts Keith–Zhong techniques for establishing local Hardy
inequalities and applies Koskela–Zhong arguments for proving self-improvement properties of local Hardy inequalities. This leads to a characterization of the Haj lasz capacity density condition
in terms of a strict upper bound on the upper Assouad codimension of the underlying set, which
shows the self-improvement property of the Haj lasz capacity density condition
Heterogeneous Parametric Trivariate Fillets
Get PDFBlending and filleting are well established operations in solid modeling and computer-aided geometric design. The
creation of a transition surface which smoothly connects the boundary surfaces of two (or more) objects has been
extensively investigated. In this work, we introduce several algorithms for the construction of, possibly heterogeneous,
trivariate fillets, that support smooth filleting operations between pairs of, possibly heterogeneous, input trivariates.
Several construction methods are introduced that employ functional composition algorithms as well as introduce a half
Volumetric Boolean sum operation. A volumetric fillet, consisting of one or more tensor product trivariate(s), is fitted
to the boundary surfaces of the input. The result smoothly blends between the two inputs, both geometrically and
material-wise (properties of arbitrary dimension). The application of encoding heterogeneous material information
into the constructed fillet is discussed and examples of all proposed algorithms are presented
Are Brain-Computer Interfaces Feasible withIntegrated Photonic Chips?
Get PDFThe present paper examines the viability of a radically novel idea for brain-computer interface (BCI), which could lead to novel technological, experimental and clinical applications. BCIs are computer-based systems that enable either one-way or two-way communication between a living brain and an external machine. BCIs read-out brain signals and transduce them into task commands, which are performed by a machine. In closed-loop the machine can stimulate the brain with appropriate signals. In recent years, it has been shown that there is some ultraweak light emission from neurons within or close to the visible and near-infrared parts of the optical spectrum. Such ultraweak photon emission (UPE) reflects the cellular (and body) oxidative status, and compelling pieces of evidence are beginning to emerge that UPE may well play an informational role in neuronal functions. In fact, several experiments point to a direct correlation between UPE intensity and neural activity, oxidative reactions, EEG activity, cerebral blood flow, cerebral energy metabolism, and release of glutamate. Therefore, we propose a novel skull implant BCI that uses UPE. We suggest that a photonic integrated chip installed on the interior surface of the skull may enable a new form of extraction of the relevant features from the UPE signals. In the current technology landsacepe, photonic technologies are advancing rapidly and poised to overtake many electrical technologies, due to their unique advantages, such as miniaturization, high speed, low thermal effects, and large integration capacity that allow for high yield, volume manufacturing, and lower cost. For our proposed BCI, we are making some very major conjectures, which need to be experimentally verified, and therefore we discuss the controversial parts, feasibility of technology and limitations, and potential impact of this envisaged technology if successfully implemented in the future.BERC.2018-2021
Severo Ochoa.SEV-2017-071
Weak sequential stability for a nonlinear model of nematic electrolytes
No full textIn this article we study a system of nonlinear PDEs modelling the electrokinetics of a nematic electrolyte material consisting of various ions species contained in a nematic liquid crystal. The evolution is described by a system coupling a Nernst-Planck system for the ions concentrations with a Maxwell's equation of electrostatics governing the evolution of the electrostatic potential, a Navier-Stokes equation for the velocityfield, and a non-smooth Allen-Cahn type equation for the nematic directorfield. We focus on the two-species case and prove apriori estimates that provide a weak sequential stability result, the main step towards proving the existence of weak solutions
Location Awareness in Beyond 5G Networks
Get PDFLocation awareness is essential for enabling contextual
services and for improving network management in 5th
generation (5G) and beyond 5G (B5G) networks. This paper
provides an overview of the expanding opportunities offered
by location awareness in wireless networks, discusses soft information
(SI)-based approaches for improved location awareness,
and presents case studies in conformity to the 3rd Generation
Partnership Project (3GPP) standardization by the European
Telecommunications Standards Institute (ETSI). Results show
that SI-based approaches can provide a new level of location
awareness in 5G and B5G networks
Hyperactivation of monocytes and macrophages in MCI patients contributes to the progression of Alzheimer's disease
Get PDFBackground: Alzheimer’s disease (AD) is the most common neurodegenerative disease ultimately manifesting as clinical dementia. Despite considerable effort and ample experimental data, the role of neuroinflammation related to systemic inflammation is still unsettled. While the implication of microglia is well recognized, the exact contribution of peripheral monocytes/macrophages is still largely unknown, especially concerning their role in the various stages of AD. Objectives: AD develops over decades and its clinical manifestation is preceded by subjective memory complaints (SMC) and mild cognitive impairment (MCI); thus, the question arises how the peripheral innate immune response changes with the progression of the disease. Therefore, to further investigate the roles of monocytes/macrophages in the progression of AD we assessed their phenotypes and functions in patients at SMC, MCI and AD stages and compared them with cognitively healthy controls. We also conceptualised an idealised mathematical model to explain the functionality of monocytes/macrophages along the progression of the disease. Results: We show that there are distinct phenotypic and functional changes in monocyte and macrophage populations as the disease progresses. Higher free radical production upon stimulation could already be observed for the monocytes of SMC patients. The most striking results show that activation of peripheral monocytes (hyperactivation) is the strongest in the MCI group, at the prodromal stage of the disease. Monocytes exhibit significantly increased chemotaxis, free radical production, and cytokine production in response to TLR2 and TLR4 stimulation. Conclusion: Our data suggest that the peripheral innate immune system is activated during the progression from SMC through MCI to AD, with the highest levels of activation being in MCI subjects and the lowest in AD patients. Some of these parameters may be used as biomarkers, but more holistic immune studies are needed to find the best period of the disease for clinical intervention
Moderately Discontinuous Homology
Get PDFWe introduce a new metric homology theory, which we call Moderately Discontinuous Homology, designed to capture Lipschitz properties of metric singular subanalytic germs. The main novelty of our approach is to allow “moderately discontinuous” chains, which are specially advantageous for capturing the subtleties of the outer metric phenomena. Our invariant is a finitely generated graded abelian group (Formula presented.) for any (Formula presented.) and homomorphisms (Formula presented.) for any (Formula presented.). Here (Formula presented.) is a “discontinuity rate”. The homology groups of a subanalytic germ with the inner or outer metric are proved to be finitely generated and only finitely many homomorphisms (Formula presented.) are essential. For (Formula presented.) Moderately Discontinuous Homology recovers the homology of the tangent cone for the outer metric and of the Gromov tangent cone for the inner one. In general, for (Formula presented.) -Homology recovers the homology of the punctured germ. Hence, our invariant can be seen as an algebraic invariant interpolating from the germ to its tangent cone. Our homology theory is a bi-Lipschitz subanalytic invariant, is invariant by suitable metric homotopies, and satisfies versions of the relative and Mayer-Vietoris long exact sequences. Moreover, fixed a discontinuity rate b we show that it is functorial for a class of discontinuous Lipschitz maps, whose discontinuities are b-moderated; this makes the theory quite flexible. In the complex analytic setting we introduce an enhancement called Framed MD homology, which takes into account information from fundamental classes. As applications we prove that Moderately Discontinuous Homology characterizes smooth germs among all complex analytic germs, and recovers the number of irreducible components of complex analytic germs and the embedded topological type of plane branches. Framed MD homology recovers the topological type of any plane curve singularity and relative multiplicities of complex analytic germs. © 2020 Wiley Periodicals LLC
Discrepancy of Minimal Riesz Energy Points
Get PDFWe find upper bounds for the spherical cap discrepancy of the set of minimizers of the Riesz s-energy on the sphere Sd. Our results are based on bounds for a Sobolev discrepancy introduced by Thomas Wolff in an unpublished manuscript where estimates for the spherical cap discrepancy of the logarithmic energy minimizers in S2 were obtained. Our result improves previously known bounds for 0 ≤ s< 2 and s≠ 1 in S2, where s= 0 is Wolff’s result, and for d- t< s< d with t≈ 2.5 when d≥ 3 and s≠ d- 1