Gravitational Lens System as a Long Baseline Detector of Extremely Low Frequency Primordial Gravitational Wave

The effect of extremely low frequency primordial gravitational wave with arbitrary direction of propagation on a non-aligned gravitational lens system is investigated. From the point of view of real astrophysical observation, singular isothermal sphere lens model is adopted in the gravitational lens system. The results show that, under the perturbation from extremely low frequency primordial gravitational wave, time delay and flux magnification in the gravitational lens system could strongly deviate from that deduced from theoretical model. This means that the strongly deviate time delay as well as flux magnification could be the imprint of extremely low frequency primordial gravitational wave on gravitational lens system, indicating that gravitational lens system could be used as a long baseline detector to detect extremely low frequency primordial gravitational wave.Comment: 8 pages, 8 figure

Formation of Retrograde Hot Jupiter Triggered by Close Encounter with Tidal Circularization

A new mechanism is proposed to account for the formation of retrograde hot Jupiter in coplanar star-planet system via close encounter between a Jupiter mass planet and a brown dwarf mass planet. After long timescale scattering between several Jupiter mass planets with inner orbits, the remaining planets still rotating around the star could have large semimajor with large eccentricity. If there exists a brown dwarf mass planet in distant orbit around the star, planetary encounter may happen. After encounter, the Jupiter mass planet may rotate around the star in a retrograde orbit with extremely large eccentricity and the periastron can reach about 0.01 AU, which means that, within the first several orbits around the star, tidal interaction from the star can shrink the semimajor axis of the planet quickly. Thus, the Jupiter mass planet is isolated from the brown dwarf mass planet due to the quick decrease of its apastron distance and eventually evolves into a retrograde hot Jupiter.Comment: 4 pages, 2 figure

Imprint of primordial gravitational wave with extremely low frequency on gravitational lens system

Primordial gravitational waves with extremely low frequency are expected to origin from inflation in the early Universe. The detection of such kind of gravitational waves is of great significance to verify the inflationary theory and determine the energy scale of inflation. Due to the foreground contamination from dust in our Milky Way galaxy, the traditional method using B-mode polarization faces challenges. In this work, we propose an alternative way of detection by investigating the effect of primordial gravitational wave with extremely low frequency on a gravitational lens system with a non-aligned source-deflector-observer configuration. The results show that, with a series of chosen parameters, gravitational lens system with perturbation from extremely low frequency primordial gravitational wave could induce time delay which could deviate from the time delay deduced from theoretical model as much as about sixty percent, meaning that gravitational lens system with a non-aligned configuration could serve as a potential long-base-line detector of extremely low frequency primordial gravitational wave.Comment: 6 pages, 4 figure

Properties of Steady Sub-Alfv\'enic Solar Wind in Comparison with Super-Alfv\'enic Wind from Measurements of Parker Solar Probe

We identify more than ten steady sub-Alfv\'enic solar wind intervals from the measurements of the Parker Solar Probe (PSP) from encounter 8 to encounter 14. An analysis of these sub-Alfv\'enic intervals reveals similar properties and similar origins. In situ measurements show that these intervals feature a decreased radial Alfv\'en Mach number resulting from a reduced density and a relatively low velocity, and that switchbacks are suppressed in these intervals. Magnetic source tracing indicates that these sub-Alfv\'enic streams generally originate from the boundaries inside coronal holes, or narrow/small regions of open magnetic fields. Such properties and origins suggest that these streams are low Mach-number boundary layers (LMBLs), which is a special component of the pristine solar wind proposed by Liu et al. We find that the LMBL wind, the fast wind from deep inside coronal holes, and the slow streamer wind constitute three typical components of the young solar wind near the Sun. In these sub-Alfv\'enic intervals, the Alfv\'en radius varies between 15 and 25 solar radii, in contrast with a typical 12 radii for the Alfv\'en radius of the super-Alfv\'enic wind. These results give a self-consistent picture interpreting the PSP measurements in the vicinity of the Sun.Comment: Accepted for publication in Ap

Adaptive Digital Twin for UAV-Assisted Integrated Sensing, Communication, and Computation Networks

In this paper, we study a digital twin (DT)-empowered integrated sensing, communication, and computation network. Specifically, the users perform radar sensing and computation offloading on the same spectrum, while unmanned aerial vehicles (UAVs) are deployed to provide edge computing service. We first formulate a multi-objective optimization problem to minimize the beampattern performance of multi-input multi-output (MIMO) radars and the computation offloading energy consumption simultaneously. Then, we explore the prediction capability of DT to provide intelligent offloading decision, where the DT estimation deviation is considered. To track this challenge, we reformulate the original problem as a multi-agent Markov decision process and design a multi-agent proximal policy optimization (MAPPO) framework to achieve a flexible learning policy. Furthermore, the Beta-policy and attention mechanism are used to improve the training performance. Numerical results show that the proposed method is able to balance the performance tradeoff between sensing and computation functions, while reducing the energy consumption compared with the existing studies.Comment: 14 pages, 11 figures

Unraveling the role of VLDL in the relationship between type 2 diabetes and coronary atherosclerosis: a Mendelian randomization analysis

BackgroundThe causal link between Type 2 diabetes (T2D) and coronary atherosclerosis has been established through wet lab experiments; however, its analysis with Genome-wide association studies (GWAS) data remains unexplored. This study aims to validate this relationship using Mendelian randomization analysis and explore the potential mediation of VLDL in this mechanism.MethodsEmploying Mendelian randomization analysis, we investigated the causal connection between T2D and coronary atherosclerosis. We utilized GWAS summary statistics from European ancestry cohorts, comprising 23,363 coronary atherosclerosis patients and 195,429 controls, along with 32,469 T2D patients and 183,185 controls. VLDL levels, linked to SNPs, were considered as a potential mediating causal factor that might contribute to coronary atherosclerosis in the presence of T2D. We employed the inverse variance weighted (IVW), Egger regression (MR-Egger), weighted median, and weighted model methods for causal effect estimation. A leave-one-out sensitivity analysis was conducted to ensure robustness.ResultsOur Mendelian randomization analysis demonstrated a genetic association between T2D and an increased coronary atherosclerosis risk, with the IVW estimate at 1.13 [95% confidence interval (CI): 1.07–1.20]. Additionally, we observed a suggestive causal link between T2D and VLDL levels, as evidenced by the IVW estimate of 1.02 (95% CI: 0.98–1.07). Further supporting lipid involvement in coronary atherosclerosis pathogenesis, the IVW-Egger estimate was 1.30 (95% CI: 1.06–1.58).ConclusionIn conclusion, this study highlights the autonomous contributions of T2D and VLDL levels to coronary atherosclerosis development. T2D is linked to a 13.35% elevated risk of coronary atherosclerosis, and within T2D patients, VLDL concentration rises by 2.49%. Notably, each standard deviation increase in VLDL raises the likelihood of heart disease by 29.6%. This underscores the significant role of lipid regulation, particularly VLDL, as a mediating pathway in coronary atherosclerosis progression

Biointerface topography mediates the interplay between endothelial cells and monocytes

Endothelial cell (EC) monolayers located in the inner lining of blood vessels serve as a semipermeable barrier between circulating blood and surrounding tissues. The structure and function of the EC monolayer affect the recruitment and adhesion of monocytes, which plays a pivotal role in the development of inflammation and atherosclerosis. Here we investigate the effect of material wrinkled topographies on the responses of human umbilical vein endothelial cells (HUVECs) and adhesion of monocytes to HUVECs. It is found that HUVEC responses are non-linearly mediated by surface topographies with different dimensions. Specifically, more cell elongation and better cell orientation on the wrinkled surface with a 3.5 μm amplitude and 10 μm wavelength (W10) are observed compared to other surfaces. The proliferation rate of HUVECs on the W10 surface is higher than that on other surfaces due to more 5-ethynyl-2′-deoxyuridine (EdU) detected on the W10 surface. Also, greater expression of inflammatory cytokines from HUVECs and adhesion of monocytes to HUVECs on the W10 surface is shown than other surfaces due to greater expression of p-AKT and ICAM, respectively. This study offers a new in vitro system to understand the interplay between HUVEC monolayers and monocytes mediated by aligned topographies, which may be useful for vascular repair and disease modeling for drug testing