Effective metric of spinless binaries with radiation-reaction effect up to fourth Post-Minkowskian order in effective-one-body theory

By means of the scattering angles, we obtain an effective metric of spinless binaries with radiation-reaction effects up to fourth post-Minkowskian order, which is the foundation of the effective-one-body theory. We note that there are freedoms for the parameters of the effective metric because one equation corresponds to two parameters for each post-Minkowskian order. Accordingly, in order to construct a self-consistent effective-one-body theory in which the Hamiltonian, radiation-reaction forces and waveforms for the ``plus" and ``cross" modes of the gravitational wave should be based on the same physical model, we can fix these freedoms by requiring the null tetrad component of the gravitationally perturbed Weyl tensor $\Psi_4^B$ to be decoupled in the effective spacetime.Comment: 17 page

The structure and function of the global citrus rhizosphere microbiome

Citrus is a globally important, perennial fruit crop whose rhizosphere microbiome is thought to play an important role in promoting citrus growth and health. Here, we report a comprehensive analysis of the structural and functional composition of the citrus rhizosphere microbiome. We use both amplicon and deep shotgun metagenomic sequencing of bulk soil and rhizosphere samples collected across distinct biogeographical regions from six continents. Predominant taxa include Proteobacteria, Actinobacteria, Acidobacteria and Bacteroidetes. The core citrus rhizosphere microbiome comprises Pseudomonas, Agrobacterium, Cupriavidus, Bradyrhizobium, Rhizobium, Mesorhizobium, Burkholderia, Cellvibrio, Sphingomonas, Variovorax and Paraburkholderia, some of which are potential plant beneficial microbes. We also identify over-represented microbial functional traits mediating plant-microbe and microbe-microbe interactions, nutrition acquisition and plant growth promotion in citrus rhizosphere. The results provide valuable information to guide microbial isolation and culturing and, potentially, to harness the power of the microbiome to improve plant production and health

Safety evaluation of urban transit signal system based on the improved TOPIS

AbstractSafety evaluation is one of the most effective countermeasures to improve the safety in modern urban transit system. This paper now applies that method to get the order preference of safety in all fault modes in a urban transit signal system using TOPIS based entropy weight for safety evaluation. TOPSIS is based on the concept that the chosen alternative should have the shortest distance from the positive ideal solution (PIS) and the farthest distance from the negative ideal solution (NIS). Entropy weight is ascertained by entropy theory, and the subjectivity in ascertaining the weights of more factors in lower hierarchy is avoided. The evaluation result indicates that this method is easy and can be implemented as an effective method in safety evaluation of urban transit signal system

Self-consistent effective-one-body theory for spinning binaries based on post-Minkowskian approximation

This paper extends the research on the self-consistent effective-one-body theory of a real spinless two-body system based on the post-Minkowskian approximation (Science China, 65, 100411, (2022)) to the case of a binary system for the spinning black holes. An effective rotating metric and an improved Hamiltonian for the spinning black hole binaries were constructed. The decoupled equation for the null tetrad component of the gravitational perturbed Weyl tensor $\psi^B_{4}$ in the effective rotating spacetime is found with the help of the gauge transform characteristics of the Weyl tensors. The decoupled equation is then separated between radial and angular variables in the slowly rotating background spacetime, and a formal solution of $\psi^B_{4}$ is obtained. On this basis, the formal expressions of the radiation reaction force and the waveform for the ``plus'' and ``cross'' modes of the gravitational wave are presented. These results, obtained in the same effective spacetime, constitute a self-consistent effective-one-body theory for the spinning black hole binaries based on the post-Minkowskian approximation.Comment: 29 pages. arXiv admin note: text overlap with arXiv:2208.0242

Tribochemical Behavior of Pure Magnesium During Sliding Friction

Reciprocating sliding friction tests were conducted on pure magnesium using a UMT-II tester. The tribo-chemical behavior was characterized using X-ray photoelectron spectroscopy (XPS) and electron probe micro-analyzer (EPMA), which showed that the tribo-chemical behavior of pure magnesium was due to a tribo-oxidation reaction. At room temperature, the debris layer on the worn surface contained Mg(OH)2, MgO, and MgCO3. According to the reciprocating sliding friction mechanism, the decomposition of MgCO3 into MgO should occur. XPS results revealed that the surface oxide layer, containing Mg(OH)2, and MgO, acted as a third layer to protect the surface. Apparently, Mg(OH)2·nH2O was the main tribo-chemical product of pure magnesium under sliding friction