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In this letter, we report the observational constraints on a Bianchi type I anisotropic extension of $w$CDM model with spatial curvature from observational data including Baryon Acoustic Oscillations (BAO), Cosmic chronometers (CC), Big Bang nucleosynthesis (BBN), Pantheon+ (PP) compilation of SNe Ia and SH0ES Cepheid host distance anchors. The anisotropy is found to be of the order $10^{-13}$, which interplay with spatial curvature to reduce $H_0$ tension by $\sim 1\sigma$ as found in the analyses with BAO+CC+BBN+PP combination of data, while no significant effect of anisotropy is observed with BAO+CC+BBN+PPSH0ES combination of data. A closed Universe is favored by $w$CDM as well as anisotropic $w$CDM models with spatial curvature in analyses with BAO+CC+BBN+PP combination of data. An observation of an open Universe from $w$CDM model with spatial curvature in analyses with BAO+CC+BBN+PPSH0ES combination of data and a closed Universe from anisotropic $w$CDM model with curvature in analyses with same combination of data is made. The quintessence form of dark energy is favored at 95\% CL in both analyses., Comment: 7 pages, 4 figures, 1 table

In this paper, we derive observational constraints on an anisotropic $w$CDM model from observational data including Baryonic Acoustic Oscillations (BAOs), Cosmic Chronometer (CC), Big Bang Nucleosynthesis (BBN), Pantheon Plus (PP) compilation of Type Ia supernovae, and SH0ES Cepheid host distance anchors. We find that anisotropy is of the order $10^{-13}$, and its presence in the $w$CDM model reduces $H_0$ tension by $\sim 2\sigma$ and $\sim 1\sigma$ in the analyses with BAO+CC+BBN+PP and BAO+CC+BBN+PPSH0ES data combinations, respectively. In both analyses, the quintessence form of dark energy is favored at 95\% CL., Comment: 11 pages, 4 figures, 3 tables

In this paper, we investigate an extension of the standard $\Lambda$CDM model by allowing: a temporal evolution in the equation of state (EoS) of DM via Chevallier-Polarski-Linder parametrization, and the constant non-null sound speed. We also consider the properties of neutrinos, such as the effective neutrino mass and the effective number of neutrino species as free parameters. We derive the constraints on this scenario by using the data from the Planck-2018 cosmic microwave background (CMB), baryonic acoustic oscillation (BAO) measurements, Pantheon+ compilation of Type Ia supernovae (SNe Ia), and some large scale structure (LSS) information from the cosmic shear surveys: Kilo Degree Survey (KiDS)-1000 and Dark Energy Survey (DES). We find constraints on the EoS and sound speed of DM very close to the null value in all the analyses, and thus no significant evidence is found beyond the standard CDM paradigm. In all the analyses, we find the significantly tight upper bounds on the sum of neutrino masses, and significantly lower mean values of $S_8$, which are in agreement with the LSS measurements. Thus, the well-known $S_8$ tension is reconciled in the considered model., Comment: 10 pages, 3 Figure panels

Cosmic Microwave Background (CMB) independent approaches are frequently used in the literature to provide estimates of Hubble constant ($H_0$). In this work, we report CMB independent constraints on $H_0$ in an anisotropic extension of $\Lambda$CDM model using the Big Bang Nucleosynthesis (BBN), Baryonic Acoustic Oscillations (BAOs), Cosmic Chronometer (CC), and Pantheon+ (PP) compilation of Type Ia supernovae and SH0ES Cepheid host distance anchors data. In the anisotropic model, we find $H_{\rm 0}=70.1^{+1.2}_{-1.5}\; (72.67\pm 0.85)\;\rm km\, s^{-1}\, Mpc^{-1}$ both with 68\% CL from BAO+BBN+CC+PP (BAO+BBN+CC+PPSH0ES) data. The analyses of the anisotropic model with the two combinations of data sets reveal that anisotropy is positively correlated with $H_0$, and an anisotropy of the order $10^{-14}$ in the anisotropic model reduces the $H_0$ tension by $\sim 2\sigma$., Comment: 9 pages, 1 table and 1 figure; matches the version published in Physics of the Dark Universe

The surface tension of living cells and tissues originates from the generation of nonequilibrium active stresses within the cell cytoskeleton. Here, using laser ablation, we generate gradients in the surface tension of cellular aggregates as models of simple tissues. These gradients of active surface stress drive large-scale and rapid toroidal motion. Subsequently, the motions spontaneously reverse as stresses reaccumulate and cells return to their original positions. Both forward and reverse motions resemble Marangoni flows in viscous fluids. However, the motions are faster than the timescales of viscoelastic relaxation, and the surface tension gradient is proportional to mechanical strain at the surface. Further, due to active stress, both the surface tension gradient and surface strain are dependent upon the volume of the aggregate. These results indicate that surface tension can induce rapid and highly correlated elastic deformations in the maintenance of tissue shape and configuration.

The present study reveals observational constraints on the coupling between dark components of anisotropic Bianchi type I universe. We assume interaction between dark matter and dark energy and split the continuity equation with inclusion of interaction term $\Gamma$. Two scenarios have been considered (i) when coupling between dark components is constant and (ii) when it is a function of redshift ($z$). Metropolis-Hasting algorithm has been used to perform Monte Carlo Markov Chain (MCMC) analysis by using observational Hubble data obtained from cosmic chronometric (CC) technique, cosmic microwave background (CMB) baryon acoustic oscillation (BAO), Pantheon compilation of Supernovae type Ia (SNIa), their joint combination and a Gaussian prior on the Hubble parameter $H_{0}$. It is obtained that the combination of all databases plus $H_{0}$ prior marginalized over a present dark energy density gives stringent constraints on the current value of coupling as $-0.001<\delta<0.041$ in constant coupling model and $-0.042<\delta<0.053$ in varying coupling model at 68\% confident level. In general, for both models, we found $\omega^{X}\approx -1$ and $\delta(\delta_{0})\approx 0$ which indicate that still recent data favor uncoupled $\Lambda$CDM model. Our estimations show that in constant coupling model $(H_{0}=73.9^{+1.5}_{-0.95}, \delta=0.023^{+0.017}_{-0.024})$ which naturally leads to consistent value of the Hubble constant. This result is interesting because the previous works show that such a high value of Hubble constant requires the significant value of coupling parameter $\delta$. It has been also observed that in the constant coupling model, we do not find any disagreement between the estimated $H_{0}$ and those reported by Hubble space telescope (HST) and large scale structure (LSS) experiments., Comment: 11 pages, 21 figures

The actin cytoskeleton is an active semi-flexible polymer network whose non-equilibrium properties coordinate both stable and contractile behaviors to maintain or change cell shape. While myosin motors drive the actin cytoskeleton out-of-equilibrium, the role of myosin-driven active stresses in the accumulation and dissipation of mechanical energy is unclear. To investigate this, we synthesize an actomyosin material in vitro whose active stress content can tune the network from stable to contractile. Each increment in activity determines a characteristic spectrum of actin filament fluctuations which is used to calculate the total mechanical work and the production of entropy in the material. We find that the balance of work and entropy does not increase monotonically and, surprisingly, the entropy production rate is maximized in the non-contractile, stable state. Our study provides evidence that the origins of system entropy production and activity-dependent dissipation arise from disorder in the molecular interactions between actin and myosin, Comment: 31 pages, 5 figures

Essentially all biology is active and dynamic. Biological entities autonomously sense, com- pute, and respond using energy-coupled ratchets that can produce force and do work. The cytoskeleton, along with its associated proteins and motors, is a canonical example of biological active matter, which is responsible for cargo transport, cell motility, division, and morphol- ogy. Prior work on cytoskeletal active matter systems showed either extensile or contractile dynamics. Here, we demonstrate a cytoskeletal system that can control the direction of the network dynamics to be either extensile, contractile, or static depending on the concentration of filaments or transient crosslinkers through systematic variation of the crosslinker or micro- tubule concentrations. Based off these new observations and our previously published results, we created a simple one-dimensional model of the interaction of filaments within a bundle. Despite its simplicity, our model recapitulates the observed activities of our experimental sys- tem, implying that the dynamics of our finite networks of bundles are driven by the local filament-filament interactions within the bundle. Finally, we show that contractile phases can result in autonomously motile networks that resemble cells. Our experiments and model allow us to gain a deeper understanding of cytoskeletal dynamics and provide a stepping stone for designing active, autonomous systems that could potentially dynamically switch states., Comment: 6 figures, 13 pages