Empirical metallicity-dependent calibrations of effective temperature against colours for dwarfs and giants based on interferometric data

We present empirical metallicity-dependent calibrations of effective temperature against colours for dwarfs of luminosity classes IV and V and for giants of luminosity classes II and III, based on a collection from the literature of about two hundred nearby stars with direct effective temperature measurements of better than 2.5 per cent. The calibrations are valid for an effective temperature range 3,100 - 10,000 K for dwarfs of spectral types M5 to A0 and 3,100 - 5,700 K for giants of spectral types K5 to G5. A total of twenty-one colours for dwarfs and eighteen colours for giants of bands of four photometric systems, i.e. the Johnson ($UBVR_{\rm J}I_{\rm J}JHK$), the Cousins ($R_{\rm C}I_{\rm C}$), the Sloan Digital Sky Survey (SDSS, $gr$) and the Two Micron All Sky Survey (2MASS, $JHK_{\rm s}$), have been calibrated. Restricted by the metallicity range of the current sample, the calibrations are mainly applicable for disk stars ([Fe/H]$\,\gtrsim\,-1.0$). The normalized percentage residuals of the calibrations are typically 2.0 and 1.5 per cent for dwarfs and giants, respectively. Some systematic discrepancies at various levels are found between the current scales and those available in the literature (e.g. those based on the infrared flux method IRFM or spectroscopy). Based on the current calibrations, we have re-determined the colours of the Sun. We have also investigated the systematic errors in effective temperatures yielded by the current on-going large scale low- to intermediate-resolution stellar spectroscopic surveys. We show that the calibration of colour ($g-K_{\rm s}$) presented in the current work provides an invaluable tool for the estimation of stellar effective temperature for those on-going or upcoming surveys.Comment: 28 pages, 19 figures, 8 tables, accepted for publication in MNRA

The Interaction between Tides and Storm Surges for the Taiwan Coast-A Modeling Investigation

Source: ICHE Conference Archive - https://mdi-de.baw.de/icheArchive

Study on the Rheological Properties and Constitutive Model of Shenzhen Mucky Soft Soil

In order to obtain the basic parameters of numerical analysis about the time-space effect of the deformation occurring in Shenzhen deep soft-soil foundation pit, a series of triaxial consolidated-undrained shear rheology tests on the peripheral mucky soft soil of a deep foundation pit support were performed under different confining pressures. The relations between the axial strain of the soil and time, as well as between the pore-water pressure of the soil and time, were achieved, meanwhile on the basis of analyzing the rheological properties of the soil, the relevant rheological models were built. Analysis results were proved that the rheology of Shenzhen mucky soft soil was generally viscous, elastic, and plastic, and had a low yield stress between 90 and 150 kPa. The increase in pore-water pressure made the rheological time effect of the mucky soft soil more remarkable. Thus, the drainage performance in practical engineering should be improved to its maximum possibility extent to decrease the soft-soil rheological deformation. Lastly, a six-component extended Burgers model was employed to fit the test results and the parameters of the model were determined. Findings showed that the extended Burgers model could satisfactorily simulate the various rheological stages of the mucky soft soil. The constitutive model and the determination of its parameters can be served as a foundation for the time-space effect analysis on the deformation of deep soft-soil foundation pits

Impact of Lycium barbarum polysaccharide on apoptosis in Mycoplasma-infected splenic lymphocytes

Purpose: To evaluate the effect of Lycium barbarum polysaccharide (LBP) on apoptosis in Mycoplasma-infected splenic lymphocytes (SLs), and the underlying mechanisms.Methods: SLs isolated from C57BL/6J mice were infected with Mycoplasma. The infected SLs were administered at different concentrations of LBP for 4 h, and the proportions of apoptotic cells and levels of relative reactive oxygen species (ROS) were determined by flow cytometry. The expressions of proapoptotic genes and endogenous antioxidant enzymes were investigated by real-time polymerase chain reaction (RT-PCR) and Western blotting.Results: LBP treatment produced dose-dependent reductions in apoptotic ratio and intracellular ROS levels of SLs (p < 0.05). In addition, the expressions of pro-apoptotic genes were decreased by LBP treatment with respect to mRNA and protein levels (p < 0.05). In contrast, mRNA and protein levels of anti-apoptotic factor Bcl-2 were significantly increased in a dose-dependent manner (p < 0.05). Furthermore, RT-PCR and Western blot results demonstrated that the expression levels of mRNA and proteins in Nrf2, HO-1 and NQO1 were up-regulated by Mycoplasma infection (p < 0.01), and further increased by LBP treatment (p < 0.05).Conclusion: LBP exerts a hyperactive antioxidant response encoded by Nrf2 to protect SLs from apoptosis induced by ROS-related oxidative damage after Mycoplasma infection. These results suggest that LBP may serve as a beneficial and dietary anti-Mycoplasma and anti-apoptotic agent.Keywords: Lycium barbarum polysaccharide, Splenic lymphocytes, ROS, Caspase-3, Bax, Nrf

Probing WIMPs in space-based gravitational wave experiments

Although searches for dark matter have lasted for decades, no convincing signal has been found without ambiguity in underground detections, cosmic ray observations, and collider experiments. We show by example that gravitational wave (GW) observations can be a supplement to dark matter detections if the production of dark matter follows a strong first-order cosmological phase transition. We explore this possibility in a complex singlet extension of the standard model with CP symmetry. We demonstrate three benchmarks in which the GW signals from the first-order phase transition are loud enough for future space-based GW observations, for example, BBO, U-DECIGO, LISA, Taiji, and TianQin. While satisfying the constraints from the XENON1T experiment and the Fermi-LAT gamma-ray observations, the dark matter candidate with its mass around $\sim 1$~TeV in these scenarios has a correct relic abundance obtained by the Planck observations of the cosmic microwave background radiation.Comment: 11 pages, 2 figures, 2 table

Stability and chaos of the duopoly model of Kopel: A study based on symbolic computations

Since Kopel's duopoly model was proposed about three decades ago, there are almost no analytical results on the equilibria and their stability in the asymmetric case. The first objective of our study is to fill this gap. This paper analyzes the asymmetric duopoly model of Kopel analytically by using several tools based on symbolic computations. We discuss the possibility of the existence of multiple positive equilibria and establish necessary and sufficient conditions for a given number of positive equilibria to exist. The possible positions of the equilibria in Kopel's model are also explored. Furthermore, if the duopolists adopt the best response reactions or homogeneous adaptive expectations, we establish rigorous conditions for the existence of distinct numbers of positive equilibria for the first time. The occurrence of chaos in Kopel's model seems to be supported by observations through numerical simulations, which, however, is challenging to prove rigorously. The second objective is to prove the existence of snapback repellers in Kopel's map, which implies the existence of chaos in the sense of Li-Yorke according to Marotto's theorem.Comment: arXiv admin note: substantial text overlap with arXiv:2301.1262