Search

In animals, epithelial tissues are barriers against the external environment, providing protection against biological, chemical, and physical damage. Depending on the animal's physiology and behavior, these tissues encounter different types of mechanical forces and need to provide a suitable adaptive response to ensure success. Therefore, understanding tissue mechanics in different contexts is an important research area. Here, we review recent tissue mechanics discoveries in a few early-divergent non-bilaterian animals -- Trichoplax adhaerens, Hydra vulgaris, and Aurelia aurita. We highlight each animal's simple body plan and biology, and unique, rapid tissue remodeling phenomena that play a crucial role in its physiology. We also discuss the emergent large-scale mechanics that arise from small-scale phenomena. Finally, we emphasize the enormous potential of these non-bilaterian animals to be model systems for further investigation in tissue mechanics., Comment: Review paper, Comments/suggestions are welcome

A large number of observations have shown that the dark matter halo surface density, given by the product of halo core radius and core density is nearly constant for a diverse suite of galaxies. Although this invariance of the halo surface density is violated at galaxy cluster and group scales, it is still an open question on whether the aforementioned constancy on galactic scales can be explained within $\Lambda$CDM. For this purpose, we probe the variation of halo surface density as a function of mass using multi-wavelength mock galaxy catalogs from $\Lambda$CDM simulations, where the adiabatic contraction of dark matter halos in the presence of baryons has been taken into account. We find that these baryonified $\Lambda$CDM halos were best fitted with a generalized-NFW profile, and the halo surface density from these halos has a degeneracy with respect to both the halo mass and the virial concentration. We find that the correlation with mass when averaged over concentration is consistent with a constant halo surface density. However, a power-law dependence as a function of halo mass also cannot be ruled out., Comment: 10 pages, 11 figures. Accepted for publications in MNRAS

Artificial intelligence technologies that can assist with at-home tasks have the potential to help older adults age in place. Robot assistance in particular has been applied towards physical and cognitive support for older adults living independently at home. Surveys, questionnaires, and group interviews have been used to understand what tasks older adults want robots to assist them with. We build upon prior work exploring older adults' task preferences for robot assistance through field interviews situated within older adults' aging contexts. Our findings support results from prior work indicating older adults' preference for physical assistance over social and care-related support from robots and indicating their preference for control when adopting robot assistance, while highlighting the variety of individual constraints, boundaries, and needs that may influence their preferences., Comment: 5 pages, 2 figures, AAAI Workshop on User-Centric Artificial Intelligence for Assistance in At-Home Tasks

In this work, we analyze the residual-based a posteriori error estimation of the multi-scale cancer invasion model, which is a system of three non-stationary reaction-diffusion equations. We present the numerical results of a study on a posteriori error control strategies for FEM approximations of the model. In this paper, we derive a residual type error estimator for the cancer invasion model and illustrate its practical performance on a series of computational tests in three-dimensional spaces. We show that the error estimator is reliable and efficient regarding the model's small perturbation parameters.

Indoor photovoltaics are receiving tremendous attention due to the continuous development of the Internet of Things (IoT). Here we report a triple anion (TA) perovskite CH3NH3PbI2.6(BrCl)0.2 with a tailored bandgap suitable for maximizing indoor light harvesting compared to methyl ammonium lead iodide CH3NH3PbI3. The best-performing TA perovskite indoor-photovoltaic device achieved a steady-state power conversion efficiency (PCE) of 25.1% with an output power density of ~ 75 microW/cm2 under 1000 lux indoor illumination (0.3 mW/cm2 irradiance). This PCE is almost 40% higher than that of equivalent CH3NH3PbI3-based devices (PCE of 17.9%). Longer carrier lifetime, reduced density of trap states and improved crystalline quality were achieved by the triple anion alloying method. The decisive role of chlorine (Cl) in the better performance of TA-based indoor photovoltaic devices was further investigated by successively reducing the Cl content and correlating it with the corresponding photovoltaic device performance. Replacing the commonly used hole transporting layer of Spiro-MeOTAD with undoped P3HT was found to significantly reduce the current-voltage hysteresis under indoor lighting conditions. A graphene-coated textile fiber-based temperature sensor was successfully powered by the triple anion perovskite indoor photovoltaic devices. The results from the present study demonstrate a novel route to maximize the PCE of halide perovskite indoor photovoltaic devices and their potential for application in the IoT industry., Comment: 27 pages, 5 figures

Injection locking is a well-established technique widely used in optics as well as solid-state devices for efficient suppression of noise. We present the spectroscopic characterization of the effect of the injection-locking signal (ILS) in mitigating the phase noise of a Josephson parametric oscillator (JPO), whose output oscillating phase undergoes indeterministic switching between the bistable states with symmetry $\theta \rightarrow{\theta+\pi}$. With the injection of a weak locking signal, we measure the phase noise power spectral density of the self-sustained oscillator output state for different locking signal strengths. We observed suppression of phase noise by injection locking. As the ILS strength surpasses more than a few photons, the output state stays completely pinned to the locking phase of the ILS, and the random telegraphic noise due to the switching of the states is significantly suppressed.

Recent years have seen a growth in the number of industrial robots working closely with end-users such as factory workers. This growing use of collaborative robots has been enabled in part due to the availability of end-user robot programming methods that allow users who are not robot programmers to teach robots task actions. Programming by Demonstration (PbD) is one such end-user programming method that enables users to bypass the complexities of specifying robot motions using programming languages by instead demonstrating the desired robot behavior. Demonstrations are often provided by physically guiding the robot through the motions required for a task action in a process known as kinesthetic teaching. Kinesthetic teaching enables users to directly demonstrate task behaviors in the robot's configuration space, making it a popular end-user robot programming method for collaborative robots known for its low cognitive burden. However, because kinesthetic teaching restricts the programmer's teaching to motion demonstrations, it fails to leverage information from other modalities that humans naturally use when providing physical task demonstrations to one other, such as gaze and speech. Incorporating multimodal information into the traditional kinesthetic programming workflow has the potential to enhance robot learning by highlighting critical aspects of a program, reducing ambiguity, and improving situational awareness for the robot learner and can provide insight into the human programmer's intent and difficulties. In this extended abstract, we describe a preliminary study on multimodal kinesthetic demonstrations and future directions for using multimodal demonstrations to enhance robot learning and user programming experiences., Comment: 6 pages, 6 figures, 2021 RSS Workshop on Accessibility of Robot Programming and the Work of the Future

The cool-core galaxy cluster RXJ1720.1+2638 hosts extended radio emission near the cluster core, known as a minihalo. The origin of this emission is still debated and one piece of the puzzle has been the question of whether the supermassive black hole in the brightest central galaxy is actively powering jets. Here we present high-resolution e-MERLIN observations clearly indicating the presence of sub-kpc jets; this may have implications for the proposed origin of the minihalo emission, providing an ongoing source of relativistic electrons rather than a single burst sometime in the past, as previously assumed in simulations attempting to reproduce observational characteristics of minihalo-hosting systems., Comment: 5 pages, 4 figures. Minor changes from v1, accepted to MNRAS

We perform the noise spectroscopy of a Josephson parametric oscillator (JPO) by implementing a microwave homodyne interferometric measurement scheme. We observe the fluctuations in the self-oscillating output field of the JPO for a long 10 s time interval in a single shot measurement and characterize the phase and amplitude noise. Furthermore, we investigate the effects of the pump strength on the output noise power spectra of the JPO. We found strong fluctuations in the phase with a $1/f^2$ characteristics in the phase noise power spectrum, which is suppressed by increasing the pump strength.