Abstract
We present the fourth Open Gravitational-wave Catalog (4-OGC) of binary neutron star (BNS), binary black hole (BBH), and neutron star–black hole (NSBH) mergers. The catalog includes ...observations from 2015 to 2020 covering the first through third observing runs (O1, O2, O3a, and O3b) of Advanced LIGO and Advanced Virgo. The updated catalog includes seven BBH mergers that were not previously reported with high significance during O3b for a total of 94 observations: 90 BBHs, 2 NSBHs, and 2 BNSs. The most confident new detection, GW200318_191337, has component masses
49.1
−
12.0
+
16.4
M
⊙
and
31.6
−
11.6
+
12.0
M
⊙
;
its redshift of
0.84
−
0.35
+
0.4
(90% credible interval) may make it the most distant merger so far. We estimate the merger rate of BBH sources, assuming a power-law mass distribution containing an additive Gaussian peak, to be
16.5
−
6.2
+
10.4
(
25.0
−
8.0
+
12.6
)
Gpc
−3
yr
−1
at a redshift of
z
= 0 (0.2). For BNS and NSBH sources, we estimate a merger rate of
200
−
148
+
309
Gpc
−3
yr
−1
and
19
−
14
+
30
Gpc
−3
yr
−1
, respectively, assuming the known sources are representative of the total population. We provide reference parameter estimates for each of these sources using an up-to-date model accounting for instrumental calibration uncertainty. The corresponding data release also includes our full set of subthreshold candidates.
Abstract
We present the third open gravitational-wave catalog (3-OGC) of compact-binary coalescences, based on the analysis of the public LIGO and Virgo data from 2015 through 2019 (O1, O2, O3a). Our ...updated catalog includes a population of 57 observations, including 4 binary black hole mergers that had not been previously reported. This consists of 55 binary black hole mergers and the 2 binary neutron star mergers, GW170817 and GW190425. We find no additional significant binary neutron star or neutron star–black hole merger events. The most confident new detection is the binary black hole merger GW190925_232845, which was observed by the LIGO–Hanford and Virgo observatories with
astro
>
0.99
;
its primary and secondary component masses are
20.2
−
2.5
+
3.9
M
⊙
and
15.6
−
2.6
+
2.1
M
⊙
, respectively. We estimate the parameters of all binary black hole events using an up-to-date waveform model that includes both subdominant harmonics and precession effects. To enable deep follow up as our understanding of the underlying populations evolves, we make available our comprehensive catalog of events, including the subthreshold population of candidates, and the posterior samples of our source parameter estimates.
Current methods for skeleton-based human action recognition usually work with complete skeletons. However, in real scenarios, it is inevitable to capture incomplete or noisy skeletons, which could ...significantly deteriorate the performance of current methods when some informative joints are occluded or disturbed. To improve the robustness of action recognition models, a multi-stream graph convolutional network (GCN) is proposed to explore sufficient discriminative features spreading over all skeleton joints, so that the distributed redundant representation reduces the sensitivity of the action models to non-standard skeletons. Concretely, the backbone GCN is extended by a series of ordered streams which is responsible for learning discriminative features from the joints less activated by preceding streams. Here, the activation degrees of skeleton joints of each GCN stream are measured by the class activation maps (CAM), and only the information from the unactivated joints will be passed to the next stream, by which rich features over all active joints are obtained. Thus, the proposed method is termed richly activated GCN (RA-GCN). Compared to the state-of-the-art (SOTA) methods, the RA-GCN achieves comparable performance on the standard NTU RGB+D 60 and 120 datasets. More crucially, on the synthetic occlusion and jittering datasets, the performance deterioration due to the occluded and disturbed joints can be significantly alleviated by utilizing the proposed RA-GCN.
Macrophages are highly heterogeneous and exhibit a diversity of functions and phenotypes. They can be divided into pro‐inflammatory macrophages (M1) and anti‐inflammatory macrophages (M2). Diabetic ...wounds are characterized by a prolonged inflammatory phase and difficulty in healing due to the accumulation of pro‐inflammatory (M1) macrophages in the wound. Therefore, hydrogel dressings with macrophage heterogeneity regulation function hold great promise in promoting diabetic wound healing in clinical applications. However, the precise conversion of pro‐inflammatory M1 to anti‐inflammatory M2 macrophages by simple and biosafe approaches is still a great challenge. Here, an all‐natural hydrogel with the ability to regulate macrophage heterogeneity is developed to promote angiogenesis and diabetic wound healing. The protocatechuic aldehyde hybridized collagen‐based all‐natural hydrogel exhibits good bioadhesive and antibacterial properties as well as reactive oxygen species scavenging ability. More importantly, the hydrogel is able to convert M1 macrophages into M2 macrophages without the need for any additional ingredients or external intervention. This simple and safe immunomodulatory approach shows great application potential for shortening the inflammatory phase of diabetic wound repair and accelerating wound healing.
An all‐natural hydrogel composed of small molecules pro‐catechol and collagen is developed to promote diabetic wound healing by modulating macrophage heterogeneity. The hydrogel exhibits good bioadhesive, antibacterial, and reactive oxygen species scavenging abilities. In vitro and in vivo experiments show that the hydrogel is able to promote the conversion of pro‐inflammatory (M1) macrophages to anti‐inflammatory (M2) macrophages and the expression of anti‐inflammatory factors.
Full text
Available for:
FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SAZU, SBCE, SBMB, UL, UM, UPUK
Strong interchain interactions of conjugated polymers usually result in poor miscibility with molecular dopants, limiting the doping efficiency because of uncontrolled phase separation. We have ...developed a strategy to achieve efficient charge‐transport and high doping miscibility in n‐doped conjugated polymers. We solve the miscibility issue through disorder side‐chains containing dopants better. Systemic structural characterization reveals a farther side‐chain branching point will lead to higher disorders, which provides appropriate sites to accommodate extrinsic molecular dopants without harming original chain packings and charge‐transport channels. Therefore, better sustainability of solid‐state microstructure is obtained, yielding a stable conductivity even when overloading massive dopants. This work highlights the importance of realizing high host‐dopant miscibility in molecular doping of conjugated polymers.
High host‐dopant miscibility and excellent carrier mobility can be simultaneously achieved in n‐doped conjugated polymers. High‐mobility polymers usually possess poor miscibility because of strong interchain interactions. Without harming the efficient charge‐transport based on the ordered polymer backbones packing, disordered side‐chains are introduced to accommodate dopants better without disturbing charge‐transport pathways.
Full text
Available for:
BFBNIB, FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SAZU, SBCE, SBMB, UL, UM, UPUK
Abstract
Einstein's general relativity, as the most successful theory of gravity, is one of the cornerstones of modern physics. However, the experimental tests for gravity in the high energy region ...are limited. The emerging gravitational-wave astronomy has opened an avenue for probing the fundamental properties of gravity in a strong and dynamical field, and in particular, a high energy regime. In this work, we test the parity conservation of gravity with gravitational waves. If the parity symmetry is broken, the left- and right-handed modes of gravitational waves would follow different equations of motion, dubbed as birefringence. We perform full Bayesian inference by comparing the state-of-the-art waveform with parity violation with the compact binary coalescence data released by LIGO and Virgo collaboration. We do not find any violations of general relativity, thus constrain the lower bound of the parity-violating energy scale to be 0.09 GeV through the velocity birefringence of gravitational waves. This provides the most stringent experimental test of gravitational parity symmetry to date. We also find third generation gravitational-wave detectors can enhance this bound to
GeV if there is still no violation, comparable to the current energy scale in particle physics, which indicates gravitational-wave astronomy can usher in a new era of testing the ultraviolet behavior of gravity in the high energy region.
Abstract
We present a search for gravitational waves from subsolar mass compact-binary mergers that allows for nonnegligible orbital eccentricity. Subsolar mass black holes are a signature of ...primordial origin black holes, which may be a component of dark matter. To produce binary coalescences, primordial black holes may form close binaries either in the early universe or more recently through dynamical interactions. A signature of dynamical formation would be the observation of noncircularized orbits. We search for black hole mergers where the primary mass is 0.1–7
M
⊙
and the secondary mass is 0.1–1
M
⊙
. We allow for eccentricity up to ∼0.3 at a dominant-mode gravitational-wave frequency of 10 Hz for binaries with component masses >0.5
M
⊙
. We find no convincing candidates in the public LIGO data from 2015–2017. The two most promising candidates have a false alarm rate of 1 per 3 and 4 yr, respectively, which combined is only a ∼2.4
σ
deviation from the expected Poisson rate. Given the marginal statistical significance, we place upper limits on the rate of subsolar mass mergers under the assumption of a null observation and compare how these limits may inform the possible dark matter contribution.
Charge transport of conjugated polymers in functional devices closely relates to their density of states (DOS) distributions. However, systemic DOS engineering for conjugated polymers is challenging ...due to the lack of modulated methods and the unclear relationship between DOS and electrical properties. Here, the DOS distribution of conjugated polymers is engineered to enhance their electrical performances. The DOS distributions of polymer films are tailored using three processing solvents with different Hansen solubility parameters. The highest n‐type electrical conductivity (39 ± 3 S cm−1), the highest power factor (63 ± 11 µW m−1 K−2), and the highest Hall mobility (0.14 ± 0.02 cm2 V−1 s−1) of the polymer (FBDPPV‐OEG) are obtained in three films with three various DOS distributions, respectively. Through theoretical and experimental exploration, it is revealed that the carrier concentration and transport property of conjugated polymers can be efficiently controlled by DOS engineering, paving the way for rationally fabricating organic semiconductors.
The charge transport properties of conjugated polymers relate closely to their density of states (DOS) distributions. This work enables DOS engineering of conjugated polymer by using different processing solvents to improve three electronic parameters in one polymer system: electrical conductivity, power factor, and Hall mobility. It is suggested that DOS engineering is crucial for the refinement of conjugated polymers for different electrical performances.
Full text
Available for:
BFBNIB, FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SAZU, SBCE, SBMB, UL, UM, UPUK
Rechargeable Li‐metal batteries (RLBs) can boost energy yet possess poor cycle stability and safety concerns when utilizing carbonate electrolytes. Countless effort has been invested in researching ...and developing electrolytes for RLBs to obtain stable and safe batteries. However, only few existing electrolytes meet the requirements for practical RLBs. In this perspective, the challenges of organic liquid electrolytes in the application in RLBs are summarized, and requirements for electrolytes for practical RLBs are proposed. This perspective briefly reviews the recent achievements of electrolytes (liquid‐ and solid‐state) for RLBs and analyzes the corresponding drawbacks of each electrolyte. Further, possible solutions to the existing shortcomings of various electrolytes are proposed. In particular, this perspective outlines the development strategy of in situ gelation electrolytes, accompanied by a call for people using pouch cells to evaluate performance and paying more attention to battery safety research. This perspective aims to expound on the challenges and the possible research directions of RLBs electrolytes to promote practical RLBs better.
Constructing safe and stable rechargeable Li‐metal batteries (RLBs) require electrolytes with proper properties in Li+ conductivity, processability, stability, non‐flammability, and strength. This perspective summarizes the achievements of different electrolytes for RLBs and outlined the remaining challenges. The possible strategies for the further development of electrolytes are proposed, accompanied by recalling for improving evaluation standards and safety research of RLBs.
Full text
Available for:
BFBNIB, FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SAZU, SBCE, SBMB, UL, UM, UPUK
PDF
