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Does a Gravitational Aberration Contribute to the Accelerated Expansion of the Universe?

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Communications in Computational Physics 2009年第5期5卷 1030-1044页

作者： Michal krizek Institute of Mathematics Academy of SciencesZitna 25CZ-11567 Prague 1Czech Republic

An arbitrarily small positive value of the gravitational aberration slightly increases the angular momentum of a two-body and multiple body *** could potentially contribute to the accelerated expansion of the whole *** present some geometrical,physical,geophysical,heliophysical,climatological,cosmological,and astronomical observational arguments,and also numerical tests to support this *** found a remarkable coincidence between the Hubble constant and the increasing distance of the Moon from the Earth,that is not only due to tidal *** examples illustrating the expansion caused by the gravitational aberration are *** will be modeled by a nonautonomous system of ordinary differential equations with delay.

关键词： Hubble constant causality gravitation Earth Moon Mars Runge-kutta method

Regression analysis of squeezing-induced hybrid nanofluid flow in Darcy-Forchheimer porous medium

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Applied Mathematics and Mechanics(English Edition) 2025年第1期46卷 193-208页

作者： k.MUHAMMAD M.SARFRAZ Department of Humanities and Sciences School of Electrical Engineering and Computer Science National University of Sciences and Technology Department of Mathematics Quaid-i-Azam University

This article presents a mathematical model addressing a scenario involving a hybrid nanofluid flow between two infinite parallel plates. One plate remains stationary, while the other moves downward at a squeezing velocity. The space between these plates contains a Darcy-Forchheimer porous medium. A mixture of water-based fluid with gold(Au) and silicon dioxide(Si O2) nanoparticles is formulated. In contrast to the conventional Fourier's heat flux equation, this study employs the Cattaneo-Christov heat flux equation. A uniform magnetic field is applied perpendicular to the flow direction, invoking magnetohydrodynamic(MHD) effects. Further, the model accounts for Joule heating, which is the heat generated when an electric current passes through the fluid. The problem is solved via NDSolve in MATHEMATICA. Numerical and statistical analyses are conducted to provide insights into the behavior of the nanomaterials between the parallel plates with respect to the flow, energy transport, and skin *** findings of this study have potential applications in enhancing cooling systems and optimizing thermal management strategies. It is observed that the squeezing motion generates additional pressure gradients within the fluid, which enhances the flow rate but reduces the frictional drag. Consequently, the fluid is pushed more vigorously between the plates, increasing the flow velocity. As the fluid experiences higher flow rates due to the increased squeezing effect, it spends less time in the region between the plates. The thermal relaxation, however, abruptly changes the temperature, leading to a decrease in the temperature fluctuations.

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Effects of P301L-TAU on post-translational modifications of microtubules in human iPSC-derived cortical neurons and TAU transgenic mice

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Neural Regeneration Research 2025年第8期20卷 2348-2360页

作者： Mohamed Aghyad Al kabbani Christoph köhler Hans Zempel Institute of Human Genetics Faculty of Medicine and University Hospital CologneUniversity of CologneCologneGermany Center for Molecular Medicine Cologne(CMMC) University of CologneCologneGermany Center Anatomy Department ⅡMedical FacultyUniversity of CologneCologneGermany

TAU is a microtubule-associated protein that promotes microtubule assembly and stability in the *** is missorted and aggregated in an array of diseases known as *** are essential for neuronal function and regulated via a complex set of post-translational modifications,changes of which affect microtubule stability and dynamics,microtubule interaction with other proteins and cellular structures,and mediate recruitment of microtubule-severing *** impairment of microtubule dynamics causes neuronal dysfunction,we hypothesize cognitive impairment in human disease to be impacted by impairment of microtubule *** therefore aimed to study the effects of a disease-causing mutation of TAU(P301L)on the levels and localization of microtubule post-translational modifications indicative of microtubule stability and dynamics,to assess whether P301L-TAU causes stability-changing modifications to *** investigate TAU localization,phosphorylation,and effects on tubulin post-translational modifications,we expressed wild-type or P301L-TAU in human MAPT-kO induced pluripotent stem cell-derived neurons(i Neurons)and studied TAU in neurons in the hippocampus of mice transgenic for human P301L-TAU(p R5 mice).Human neurons expressing the longest TAU isoform(2N4R)with the P301L mutation showed increased TAU phosphorylation at the AT8,but not the p-Ser-262 epitope,and increased polyglutamylation and acetylation of microtubules compared with endogenous TAU-expressing neurons.P301L-TAU showed pronounced somatodendritic presence,but also successful axonal enrichment and a similar axodendritic distribution comparable to exogenously expressed 2N4R-wildtype-TAU.P301L-TAU-expressing hippocampal neurons in transgenic mice showed prominent missorting and tauopathy-typical AT8-phosphorylation of TAU and increased polyglutamylation,but reduced acetylation,of microtubules compared with non-transgenic *** sum,P301L-TAU results in changes in micr

关键词： human induced pluripotent stem cell microtubules P301L pR5 mice TAU tauopathy tubulin code

SPLITTING A CONCAVE DOMAIN TO CONVEX SUBDOMAINS

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Journal of Computational Mathematics 1998年第4期16卷 327-336页

作者： Li-ping Liu Michal krizek(Mathematical Institute, Academy of Sciences, Zitna 25, CZ-11567 Prague 1, Czech Republic) Acad Sci Czech Republ Math Inst CZ-11567 Prague 1 Czech Republic

We examine a steady-state heat radiation problem and its finite element approximation in Rd, d = 2, 3. A nonlinear Stefan-Boltzmann boundary condition is considered. Another nonlinearity is due to the fact that the temperature is always greater or equal than 0[k]. We prove two convergence theorems for piecewise linear finite element solutions.

关键词： Nonlinear elliptic boundary value problems, heat radiation problem finite elements variational inequalities

OPTIMAL INTERIOR AND LOCAL ERROR ESTIMATES OF A RECOVERED GRADIENT OF LINEAR ELEMENTS ON NONUNIFORM TRIANGULATIONS

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Journal of Computational Mathematics 1996年第4期14卷 345-362页

作者： I. Hlavacek M. krizek(Mathematical Institute, Zitna 25, CZ-11567, Prague 1, Czech Republic) INST MATH CZ-11567 PRAGUE 1CZECH REPUBLIC

We examine a simple averaging formula for the gradieni of linear finite elemelitsin Rd whose interpolation order in the Lq-norm is O(h2) for d < 2q and nonuniformtriangulations. For elliptic problems in R2 we derive an interior superconvergencefor the averaged gradient over quasiuniform triangulations. Local error estimatesup to a regular part of the boundary and the effect of numerical integration arealso investigated.

关键词： Math Pro OPTIMAL INTERIOR AND LOCAL ERROR ESTIMATES OF A RECOVERED GRADIENT OF LINEAR ELEMENTS ON NONUNIFORM TRIANGULATIONS

Human endogenous retrovirus type-W and multiple sclerosis–related smoldering neuroinflammation

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Neural Regeneration Research 2025年第3期20卷 813-814页

作者： Joel Gruchot Laura Reiche Andrew Chan Robert Hoepner Patrick küry Department of Neurology Medical Faculty and University Hospital DüsseldorfHeinrich Heine University DüsseldorfDüsseldorfGermany Department of Neurology InselspitalBern University Hospital and University of BernBernSwitzerland

Introduction to human endogenous retrovirus type-W(HERV-W): Genomic inheritance from the past includes retroviral sequences that have been stably incorporated into our genomes and account for up to 8% of human DNA.

关键词： endogenous inflammation Human

Nucleoside modified mRNA-lipid nanoparticles as a new delivery platform for the repair of the injured spinal cord

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Neural Regeneration Research 2025年第8期20卷 2311-2312页

作者： krisztián Pajer Tamás Bellák Antal Nógrádi Department of Anatomy Histology and EmbryologyAlbert Szent-Györgyi Medical SchoolUniversity of SzegedSzegedHungary

Spinal cord injury and treatment opportunities:The adult mammalian spinal cord has a very limited capacity for spontaneous regeneration due to various intrinsic molecular and cellular *** the spinal cord neurons have the capacity to regenerate their axons,the expression of growth inhibitory factors,lack or suppression of proper guidance cues,and profound inflammatory responses do not permit successful regeneration(khyeam et al.,2021).

关键词： injured capacity modified

FINITE ELEMENT APPROXIMATION OF A NONLINEAR STEADY-STATE HEAT CONDUCTION PROBLEM

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Journal of Computational Mathematics 2001年第1期19卷 27-34页

作者： Michal krizek (Mathematical Institute, Academy of Sciences, ■itn■ 25, CZ-115 67 Prague 1, Czech Republic) Mathematical Institute Academy of Sciences 捷克斯洛伐克 CZ-115 67

Examines a nonlinear partial differential equation of elliptic type with the homogeneous Dirichlet boundary conditions; Proof of the comparison and maximum principles; Approximation of the finite element; Introduction... 详细信息

关键词： Boundary value elliptic problems Comparison principle Maximum principle Finite element method Discrete maximum principle Nonobtuse partitions.

Antigravity—Its Manifestations and Origin

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International Journal of Astronomy and Astrophysics 2013年第3期3卷 227-235页

作者： Michal krizek Lawrence Somer Institute of Mathematics Academy of SciencesPragueCzech Republic Department of Mathematics Catholic University of AmericaWashington DCUSA

Dark energy has been introduced in order to explain the observed acceleration of the expansion of our Universe. It seems to be distributed almost uniformly and it has an essential influence on the present value of the Hubble constant which characterizes the rate of this expansion. The Newtonian theory of gravitation is formulated so that the laws of conservation of energy and momentum hold. However, the Universe is designed so that the total amount of energy is slowly, but continually increasing, since its expansion is accelerating. Our examples show that even the Solar System and also our Galaxy imperceptibly expand thanks to dark energy whose origins are tiny antigravity forces. We claim that these forces appear due to the finite speed of gravitational interaction, which causes gravitational aberration effects. We show that effects of dark energy are observable;they are not only globally, but also in local systems. These effects can be measured and are comparable with the present value of the Hubble constant.

关键词： Hubble Parameter Dark Energy Antigravity Cosmological Constant Gravitational Aberration Conservation of Energy and Momentum Law Solar System