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Objectives: To investigate and analyze the effect of percutaneous minimally invasive pedicle screw internal fixation in the treatment of thoracolumbar vertebral fractures and its impact on quality of life. Methods: Fifty patients with thoracolumbar vertebral fracture admitted to our hospital from January 2015 to December 2018 were selected and divided into two groups according to different treatment regimens. The observation group was treated with minimally invasive percutaneous pedicle screw internal fixation, while the control group was treated with traditional posterior approach open pedicle screw internal fixation. The surgery time, incision length, intraoperative blood loss, postoperative drainage, hospitalization time, ambulation time, fracture healing time and postoperative VAS scores were compared between the two groups. In addition, the cobb angle, the sagittal plane index, and the anterior vertebral height were compared between the two groups before and after surgery, as were the Oswestry Disability Index (ODI) at 1d, 3 months, and 6 months postoperatively. Results: The surgery time, incision length, postoperative pain level, postoperative drainage and intraoperative blood loss of the observation group were less than those of the control group (P

It has been a half-decade since the first direct detection of gravitational waves, which signifies the coming of the era of the gravitational-wave astronomy and gravitational-wave cosmology. The increasing number of the detected gravitational-wave events has revealed the promising capability of constraining various aspects of cosmology, astronomy, and gravity. Due to the limited space in this review article, we will briefly summarize the recent progress over the past five years, but with a special focus on some of our own work for the Key Project ``Physics associated with the gravitational waves'' supported by the National Natural Science Foundation of China. In particular, (1) we have presented the mechanism of the gravitational-wave production during some physical processes of the early Universe, such as inflation, preheating and phase transition, and the cosmological implications of gravitational-wave measurements; (2) we have put constraints on the neutron star maximum mass according to GW170817 observations; (3) we have developed a numerical relativity algorithm based on the finite element method and a waveform model for the binary black hole coalescence along an eccentric orbit., v1, 93 pages, 18 figures, prepared as a status review of project report for Sci. China Phys. Mech. Astron.; v2, 95 pages, minor revision, references added, accepted for publication in Sci. China Phys. Mech. Astron; v3, to match the published version

In this work, we consider the burst signal of the dark photon, the hypothetical vector boson of the $U(1)_B$ or $U(1)_{B-L}$ gauge group, generated by a compact binary star system. The absence of the signal in the laser interferometer puts bounds on the coupling constant $\epsilon$ to the ordinary matter. It turns out that if the dark photon is massless, $\epsilon^2$ is on the order of $10^{-37}-10^{-33}$ at most; in the massive case, the upper bound of $\epsilon^2$ is about $10^{-38}-10^{-31}$ in the mass range from $10^{-19}$ eV to $10^{-11}$ eV. These are the first bounds derived from the interferometer observations independent of the assumption of dark photons being dark matter., Comment: 11 pages, 2 figures. Modified according to Referee's suggestions

Inorganic halide perovskites have attracted interest due to their high efficiency and low cost. Considering the uncertainty of experimental measurements, it was important to predict the upper limit of carrier mobility. In this study, the ab initio Boltzmann transport equation, including all electron–phonon interactions, was used to accurately predict the mobilities of CsPbI3, CsSnI3, CsPbBr3, and CsSnBr3. Using the iterative Boltzmann transport equation (IBTE), the calculated mobility for CsPbI3 is µ e = 512/µ h = 379 cm2 V−1 s−1, and Sn-based perovskite exhibited high hole mobility. The longitudinal optical phonons associated with the stretching between halogen anions and divalent metal cations were revealed to be the dominant scattering source for the carriers. Furthermore, the effect of biaxial strain on mobility was investigated. We observed that biaxial compressive strain could improve the mobility of CsPbI3 and CsPbBr3. Surprisingly, under a compressive strain of − 2 % , the mobilities of CsPbI3 using IBTE approach were improved to µ e = 1176/µ h = 936 cm2 V−1 s−1. It was revealed that the compressive strain could decrease the effective mass of CsPbI3 and CsPbBr3.

In this paper, we use a newly compiled sample of ultra-compact structure in radio quasars and strong gravitational lensing systems with quasars acting as background sources to constrain six spatially flat and non-flat cosmological models ($\Lambda$CDM, PEDE and DGP). These two sets of quasar data (the time-delay measurements of six strong lensing systems and 120 intermediate-luminosity quasars calibrated as standard rulers) could break the degeneracy between cosmological parameters ($H_0$, $\Omega_m$ and $\Omega_k$) and therefore provide more stringent cosmological constraints for the six cosmological models we study. A joint analysis of the quasar sample provides model-independent estimations of the Hubble constant $H_0$, which is strongly consistent with that derived from the local distance ladder by SH0ES collaboration in the $\Lambda$CDM and PEDE model. However, in the framework of a DGP cosmology (especially for the flat universe), the measured Hubble constant is in good agreement with that derived from the the recent Planck 2018 results. In addition, our results show that zero spatial curvature is supported by the current lensed and unlensed quasar observations and there is no significant deviation from a flat universe. For most of cosmological model we study (the flat $\Lambda$CDM, non-flat $\Lambda$CDM, flat PEDE, and non-flat PEDE models), the derived matter density parameter is completely consistent with $\Omega_m\sim 0.30$ in all the data sets, as expected by the latest cosmological observations. Finally, according to the the statistical criteria DIC, although the joint constraints provide substantial observational support to the flat PEDE model, they do not rule out dark energy being a cosmological constant and non-flat spatial hypersurfaces., Comment: 11 pages, 5 figures, accepted for publication in A&A

Observations of galaxy-scale strong gravitational lensing (SGL) systems have enabled unique tests of nonlinear departures from general relativity (GR) on the galactic and supergalactic scales. One of the most important cases of such tests is constraints on the gravitational slip between two scalar gravitational potentials. In this paper, we use a newly compiled sample of strong gravitational lenses to test the validity of GR, focusing on the screening effects on the apparent positions of lensed sources relative to the GR predictions. This is the first simultaneous measurement of the Post-Newtonian (PN) parameter ($\gamma_{PN}$) and the screening radius ($\Lambda$) without any assumptions about the contents of the Universe. Our results suggest that the measured PPN is marginally consistent with GR ($\gamma_{PN}=1$) with increasing screening radius ($\Lambda = 10-300 $kpc), although the choice of lens models may have a significant influence on the final measurements. Based on a well-defined sample of 5000 simulated strong lenses from the forthcoming LSST, our methodology will provide a strong extragalactic test of GR with an accuracy of 0.5\%, assessed up to scales of $\Lambda \sim 300$ kpc. For the current and future observations of available SGL systems, there is no noticeable evidence indicating some specific cutoff scales on kpc-Mpc scales, beyond which new gravitational degrees of freedom are expressed., Comment: 14 pages, 9 figures, accepted for publication in ApJ

It is well known that time delays due to strong lensing offer the opportunity of a one-step measurement of the Hubble constant H 0 that is independent of the cosmic distance ladder. In this paper, we go further and propose a cosmological model-independent approach to simultaneously determine the Hubble constant and cosmic curvature with measurements of the time delay due to strong lensing, without any prior assumptions regarding the content of the universe. The data we use comprise the recent compilation of six well studied strongly lensed quasars, while the cosmic chronometer data are utilized to reconstruct distances via cosmographic parameters. In the framework of third-order Taylor expansion and (2, 1) order Padé approximation for cosmographic analysis, our results provide model-independent estimations of the Hubble constant H 0 = 72.24 − 2.52 + 2.73 km s − 1 Mpc − 1 and H 0 = 72.45 − 2.02 + 1.95 km s − 1 Mpc − 1 , which are well consistent with that derived from the local distance ladder by the SH0ES collaboration. The measured cosmic curvature Ω k = 0.062 − 0.078 + 0.117 and Ω k = 0.069 − 0.103 + 0.116 shows that zero spatial curvature is supported by the current observations of time delays due to strong lensing and cosmic chronometers. Imposing the prior of spatial flatness leads to more precise (at 1.6% level) determinations of the Hubble constant H 0 = 70.47 − 1.15 + 1.14 km s − 1 Mpc − 1 and H 0 = 71.66 − 1.57 + 1.15 km s − 1 Mpc − 1 , values located between the results from Planck and the SH0ES collaboration. If a prior of local (SH0ES) H 0 measurement is adopted, the constraint on curvature parameter can be further improved to Ω k = 0.123 − 0.046 + 0.060 and Ω k = 0.101 − 0.072 + 0.090 , supporting no significant deviation from a flat universe. Finally, we also discuss the effectiveness of the Padé approximation in reconstructing the cosmic expansion history for redshifts up to z ∼ 2.3, considering its better performance in the Bayes information criterion.

We investigate the general properties of a class of scalar-field dark energy models (i.e., $\phi$CDM models) which behave like cosmological trackers at early times. Particularly, we choose three $\phi$CDM models with typical potentials, i.e., $V(\phi)\propto \phi^{-\alpha}$ (inverse power-law (IPL) model), $V(\phi)\propto \coth^{\alpha}{\phi}$ (L-model) and $V(\phi)\propto \cosh(\alpha\phi)$ (Oscillatory tracker model), where the latter two models are based on the $\alpha$-attractors originated from the study of inflation. These models, which reduce to the $\Lambda$CDM model with $\alpha \to 0$, are studied and compared with the recent observations, including the Pantheon sample of type Ia supernovae (SNe Ia), baryon acoustic oscillations (BAO) measurements extracted from 6dFGS, BOSS and eBOSS, as well as the temperature and polarization anisotropy power spectra data of cosmic microwave background radiation (CMB) from Planck 2018 results. The observational constraints from the combining sample (SNe Ia + BAO + CMB) indicate that none of the three $\phi$CDM models exclude the $\Lambda$CDM model at $68.3\%$ confidence level. We find that the CMB anisotropy data have obvious advantages in constraining the dark energy models compared with other cosmological probes, which is particularly evident in the L-model. Furthermore, we apply the Bayesian evidence to compare the $\phi$CDM models and the $\Lambda$CDM model with the analysis of the combining sample. The concordance $\Lambda$CDM model is still the most supported one. In addition, among the three $\phi$CDM models, the IPL model is the most competitive one, while the L-model/Oscillatory tacker model is moderately/strongly disfavored., Comment: 18 pages, 4 figures, 1 table; Accepted for publication in Physics of the Dark Universe (PDU)

Existing Learning from Demonstration (LfD) methods that can learn the peg-in-hole assembly skills mainly adopts the impedance control strategy, and generally do not pay attention to the assembly skill segmentation problem. This scheme is susceptible to environmental noise and is difficult to learn stable and effective assembly skills. In this paper, a geometric constraints-based LfD method is proposed and applied to the peg-in-hole assembly task. By identifying geometric constraints from the motion trajectory and considering the contact force information, the demonstration dataset is first segmented into a series of different sub-skills. Hybrid Force/Position Control (HFPC) schema is adopted to model those skills. The selection matrix is identified according to the geometric constraints. The Gaussian Mixture Model (GMM)/Gaussian Mixture Regression(GMR) and quasiperiodic motion models are used to representing the reference trajectories. A switching mechanism is also learned to coordinate those HFPCs with different configurations to accommodate different sub-skills. The experimental results show that the proposed method can accomplish the learning and reproduction of assembly tasks stably and effectively.

Parthenogenetic embryos have been widely studied as an effective tool related to paternal and maternal imprinting genes and reproductive problems for a long time. In this study, we established a parthenogenetic epiblast-like stem cell line through culturing parthenogenetic diploid blastocysts in a chemically defined medium containing activin A and bFGF named paAFSCs. The paAFSCs expressed pluripotent marker genes and germ-layer-related genes, as well as being alkaline-phosphatase-positive, which is similar to epiblast stem cells (EpiSCs). We previously showed that advanced embryonic stem cells (ASCs) represent hypermethylated naive pluripotent embryonic stem cells (ESCs). Here, we converted paAFSCs to ASCs by replacing bFGF with bone morphogenetic protein 4 (BMP4), CHIR99021, and leukemia inhibitory factor (LIF) in a culture medium, and we obtained parthenogenetic advanced stem cells (paASCs). The paASCs showed similar morphology with ESCs and also displayed a stronger developmental potential than paAFSCs in vivo by producing chimaeras. Our study demonstrates that maternal genes could support parthenogenetic EpiSCs derived from blastocysts and also have the potential to convert primed state paAFSCs to naive state paASCs.

Although the spatial curvature has been measured with very high precision, it still suffers from the well-known cosmic curvature tension. In this paper, we use an improved method to determine the cosmic curvature, by using the simulated data of binary neutron star mergers observed by the second generation space-based DECi-hertz Interferometer Gravitational-wave Observatory (DECIGO). By applying the Hubble parameter observations of cosmic chronometers to the DECIGO standard sirens, we explore different possibilities of making measurements of the cosmic curvature referring to a distant past: one is to reconstruct the Hubble parameters through the Gaussian process without the influence of hypothetical models, and the other is deriving constraints on Ω K in the framework of the non-flat Λ cold dark matter model. It is shown that in the improved method DECIGO could provide a reliable and stringent constraint on the cosmic curvature (Ω K = −0.007 ± 0.016), while we could only expect the zero cosmic curvature to be established at the precision of ΔΩ K = 0.11 in the second model-dependent method. Therefore, our results indicate that in the framework of methodology proposed in this paper, the increasing number of well-measured standard sirens in DECIGO could significantly reduce the bias of estimations for cosmic curvature. Such a constraint is also comparable to the precision of Planck 2018 results with the newest cosmic microwave background (CMB) observations (ΔΩ K ≈ 0.018), based on the concordance ΛCDM model.

The present study explores whether embodied meaning is activated in comprehension of action-related Mandarin counterfactual sentences. Participants listened to action-related Mandarin factual or counterfactual sentences describing transfer events (actions towards or away from the participant), and then performed verb-compatible or -incompatible motor action after a transfer verb (action towards or away from the participant) onset. The results demonstrated that motor simulation, specifically the interfering action-sentence compatibility effect (ACE), was obtained in both factual and counterfactual sentences. Additionally, the temporal course of motor resonance was slightly different between factual and counterfactual sentences. We concluded that embodied meaning was activated in action-related Chinese counterfactual sentences. The results supported a neural network model of Chersi, Thill, Ziemke, and Borghi (2010), proposed within the embodiment approach, which explains the interaction between processing action-related sentences and motor performance. Moreover, we speculated that the neural network model of Chersi et al. was also applicable to action-related Mandarin counterfactual comprehension.

Pd–Cu(Ni) bimetallic catalysts supported on Pb-doped manganese oxide octahedral molecular sieves(Pb-OMS-2) were prepared by deposition-precipitation method, and the activities of those bimetallic catalysts were evaluated in the oxidative carbonylation of phenol to diphenyl carbonate (DPC). The physico-chemical properties of catalysts were evaluated by various characterization techniques such as X-ray diffraction (XRD), Transmission electron microscope (TEM), Scanning transmission electron microscopy/energy-dispersive X-ray spectroscopy (STEM/EDS), Temperature-programmed reduction of hydrogen (H2-TPR) and X-ray photoelectron spectroscopy (XPS). The results showed that superior activity of bimetallic catalyst was accomplished by the addition of second metal Cu(Ni) compared to monometallic Pd catalyst. The metal particles of bimetallic catalysts were dispersed homogeneously on the surface with small particle size (3∼5 nm). The high activity and stability of bimetallic catalyst were achieved due to the formation of very active Pd–Cu(Ni) interfaces. The oxidation state of active species increased via the strong interaction between bimetallic components, and the redox capacity of Pd became stronger with the addition of the second metal. The highest DPC yield was 23.4% for Pd1Cu2 and 22.9% for Pd1Ni4 catalysts, respectively. After 20 h of reaction time, even though the DPC yield stopped growing for the monometallic catalysts, it continued to increase for the bimetallic catalysts, and the DPC yield reached about 50.0% at 24 h.

Oxygen-rich hierarchical porous carbons (PCs) were successfully prepared through the co-carbonization of mesophase pitch (MP) and biomass sawdust (BS), following KOH activation. The PCs possessed a high specific surface area and a considerable amount of oxygen functional groups on the surface due to BS containing hierarchical porous structures and an abundant of heteroatoms. Moreover, the PCs exhibited high graphitization degree due to MP with a great deal of polynuclear aromatic structural units for easily forming the graphitized structures. The results showed that the PC-5/5 obtained from the co-carbonization of MP and BS with weight ratio of 5/5 had a high oxygen functional groups (1.43 mmol/g C-OH, 0.65 mmol/g RO-C=O, 0.66 mmol/g O-C=O from Boehm titration results) and its surface area reached to 2361 m2/g. As an electrode material for supercapacitor, the prepared electrode from PC-5/5 exhibited a favorable specific capacitance of 324 F/g at a current density of 0.5 A/g in 6 mol/L KOH electrolyte. The electrode also demonstrated excellent rate ability with a retention rate of 75% when the current density increases from 0.5 to 5 A/g, and remained 95% of the capacitance at 5 A/g after 500 cycles. Therefore, the PCs obtained by co-carbonization of MP and BS have high potential as electrode materials. This route not only enhanced the benefit from biomass wastes, but also reduced the cost of producing electrode materials for supercapacitor.

A novel amorphous nanoporous PdCuNi-S electrocatalyst is synthesized by a two-step dealloying method. The as-formed nanoporous PdCuNi-S catalyst exhibits excellent catalytic activity for the hydrogen evolution reaction (HER) in acidic media, which is very close to commercial Pt/C catalyst. The overpotential at 10 mA cm−2 and Tafel slope are 48 mV and 35 mV dec−1, respectively. In addition, the catalyst shows good electrochemical stability in HER. The outstanding property of PdCuNi-S catalyst for hydrogen generation is attributed to the bicontinuous nanoporous structure, improved charge transfer, more bridging S22- and/or apical S2- in amorphous state and synergetic interactions of Pd, Cu, Ni and S.

China is severely exposed to natural hazards. Currently, there are more than 5.5 million contingency plans for handling various incidents. Similar to those produced in other counties, the paper-based plans in China are limited in that emergency responders cannot easily extract helpful information for them. In this paper, a knowledge-based system will be proposed for providing different stakeholders with helpful information in the emergency response. The conceptual model is the core for the whole system, which can link plans in the physical world and the ontology in the cyber world.

The ductile-to-brittle transition is commonly observed in metastable β-titanium (Ti) alloys containing ω-precipitates, while the fundamental understanding on ω-embrittlement hitherto remains elusive. In this work, the prototypical Ti-20 wt% Mo metastable β-Ti alloy has been systematically investigated by coupling experiments and first-principles calculation to eliminate this puzzle. It is shown that the structural evolution of ω-phase controls the deformation mechanism transition of twinning-to-slip in Ti Mo alloy, being the origin of ductile-to-brittle transition of this alloy. The initial trigonal ω-structure continuously collapses to hexagonal ω-structure (structural collapse) whilst Mo-atoms are rejected out concurrently (stoichiometric varieties), both leading to hardening of ω-precipitates. This self-hardening of ω-precipitates was further rationalized in terms of the enhanced propensity for a covalent character of the atomic bond demonstrated by the electronic density of states (DOS) from first-principles calculation. Specifically, the self-hardening behavior of ω-precipitates promotes dislocation slip on isolated planes in lieu of correlative slip on successive planes inside ω1-variant, while dislocations are completely blocked ahead ω2/ω3/ω4-variants. This in turn renders the transition from deformation twinning that contributes to great macro-plasticity to ordinary dislocation slip that contributes to localized deformation bands in the present Ti Mo alloy.

A single genome gives rise to diverse tissues through complex epigenomic mechanisms, including N6-methyladenosine (m6A), a widespread RNA modification that is implicated in many biological processes. Here, to explore the global landscape of m6A in human tissues, we generated 21 whole-transcriptome m6A methylomes across major fetal tissues using m6A sequencing. These data reveal dynamic m6A methylation, identify large numbers of tissue differential m6A modifications and indicate that m6A is positively correlated with gene expression homeostasis. We also report m6A methylomes of long intergenic non-coding RNA (lincRNA), finding that enhancer lincRNAs are enriched for m6A. Tissue m6A regions are often enriched for single nucleotide polymorphisms that are associated with the expression of quantitative traits and complex traits including common diseases, which may potentially affect m6A modifications. Finally, we find that m6A modifications preferentially occupy genes with CpG-rich promoters, features of which regulate RNA transcript m6A. Our data indicate that m6A is widely regulated by human genetic variation and promoters, suggesting a broad involvement of m6A in human development and disease.

Recently, two-dimensional (2D) GeP semiconductor was successfully obtained from single crystals using mechanical exfoliation method. In this study, uniaxial strain behaviors and carrier mobilities of monolayer GeP are investigated by first principles calculations. The stretching simulation shows that monolayer GeP can maintain a stable elastic deformation for x axis strain from zero to ɛ = 12.9%, and y axis strain from zero to ɛ = 26.2%. The structural stability can be further verified by the phonon dispersion. Carrier mobility based on acoustic deformation potential scattering mechanism is predicted by the calculations of effective mass, elastic modulus and deformation potential. The upper limits of some possible carrier mobilities are presented, and they can be tuned by uniaxial strain. Combining excellent mechanical properties with moderate band gap and tunable carrier mobility, 2D GeP has a potential application in nanoelectronics and optoelectronics.

ω phase precipitating in a β -Ti alloy is generally detrimental to the ductility and plasticity of the alloy.To understand the influence of ω phase on the mechanical properties of β -Ti alloys, the property of the β/ω interface is demanded.In this regard, we calculate the interface energies ( γ int ), cleavage energies ( γ cl ), and generalized stacking fault energies ( γ ) of the β/ω interfaces with different orientations using a first-principles method.Our calculations predict interface energies of 0.32 J m−2 and 0.03 J m−2 for the ( 1 1 1 ¯ ) β / ( 0 0 0 1 ) ω and ( 1 1 2 ) β / ( 1 0 1 ¯ 0 ) ω interfaces, respectively.The strong anisotropy of the interface energy contributes to the ellipsoid-like morphology of ω phase with its major axis parallel to the 〈 1 1 1 〉 β direction.The influence of the interface on the ductility of the alloy is discussed with the calculated cleavage energies and the unstable stacking fault energies ( γ us ) extracted from the generalized stacking fault energy (GSFE). The γ cl / γ us ratio of the ( 1 1 2 ) β / ( 1 0 1 ¯ 0 ) ω interface is lower than those of the main slip planes of the bulk phases, indicating that this interface is prone to crack initiation and propagation as compared to the bulk and contributes to theω-embrittlement of β -Ti alloys.

Background Accumulating evidence has highlighted the potential role of RNA binding proteins (RBPs) in the biological behaviors of glioblastoma cells. Herein, the expression and function of RNA binding proteins FXR1 were investigated in human glioma cells. Methods Quantitative real-time PCR were conducted to evaluate the expression of MIR17HG and miR-346, miRNA-425-5p in glioma tissues and cells. Western blot were used to explore the expression of FXR1, TAL1 and DEC1 in glioma tissues and cells. Stable knockdown of FXR1 and MIR17HG in glioma cells were established to explore the function of FXR1, MIR17HG in glioma cells. Further, RIP and RNA pull-down assays were used to investigate the correlation between FXR1 and MIR17HG. Cell Counting Kit-8, transwell assays, and flow cytometry were used to investigate the function of FXR1 and MIR17HG in malignant biological behaviors of glioma cells. ChIP assays were employed to ascertain the correlations between TAL1 and MIR17HG. Results FXR1and MIR17HG were upregulated in glioma tissues and cell lines. Downregulation of FXR1 or MIR17HG resulted in inhibition of glioma cells progression. We also found that FXR1 regulates the biological behavior of glioma cells via stabilizing MIR17HG. In addition, downregulated MIR17HG increased miR-346/miR-425-5p expression and MIR17HG acted as ceRNA to sponge miR-346/miR-425-5p. TAL1 was a direct target of miR-346/miR-425-5p, and played oncogenic role in glioma cells. More importantly, TAL1 activated MIR17HG promoter and upregulated its expression, forming a feedback loop. Remarkably, FXR1 knockdown combined with inhibition of MIR17HG resulted in the smallest tumor volumes and the longest survivals of nude mice in vivo. Conclusions FXR1/MIR17HG/miR-346(miR-425-5p)/TAL1/DEC1 axis plays a novel role in regulating the malignant behavior of glioma cells, which may be a new potential therapeutic strategy for glioma therapy. Electronic supplementary material The online version of this article (10.1186/s13046-018-0991-0) contains supplementary material, which is available to authorized users.

Realistic quantum systems always exhibit gravitational and relativistic features. In this paper, we investigate the properties of Gaussian steering and its asymmetry by the localized two-mode Gaussian quantum states, instead of the traditional single-mode approximation method in the relativistic setting. We find that the one-side Gaussian quantum steering will monotonically decrease with increasing observers of acceleration. Meanwhile, our results also reveal the interesting behavior of the Gaussian steering asymmetry, which increases for a specific range of accelerated parameter and then gradually approaches to a finite value. Such finding is well consistent and explained by the well-known Unruh effect, which could significantly destroy the one-side Gaussian quantum steering. Finally, our results could also be applied to the dynamical studies of Gaussian steering between the Earth and satellites, since the effects of acceleration are equal to the effects of gravity according to the equivalence principle.

Variant selection during solid–solid phase transformation in titanium alloys affects greatly the microstructure and mechanical properties of the alloys. Theoretical investigations of the variant selection were generally performed by using phase field simulation that considers solely the elastic coherency strain energy. In the present work, we develop a model to determine the variant selection directly from first-principles calculations. The source of the variant selection is considered to be the varying free energy gains (including both bulk and interface contributions) induced by the transformation from the parent phase to different variants of the product phase. This model is applied to investigate the effects of shear stress and alloy composition on ω variant selection during athermal β → ω transformation in binary Ti-xMo ( x ≤ 25 at.%) alloys. The random distribution of the atoms in the alloy is described by using virtual crystal approximation (VCA). We show that the tendency of variant selection becomes stronger with increasing shear stress. With increasing Mo concentration, the favorable ω variant transfers from one to another, except for the ω phase with very small particle size (e.g., radius R ≤ 1 nm) where one variant is always selected. The critical Mo concentration for the transfer of the favorable ω variant approaches to 5 at.% with increasing size of the ω phase particles and remains almost unchanged against the shear stress. At the critical Mo concentration, the considered variants have equal free energy gains and there is no variant selection. This finding opens the possibility of controlling the variant selection and the associated microstructure by changing the composition of the alloys.

Mobile phones have laid a significant effect on college students with the development of science and technology. Referring to previous survey, the number of phubbing quantity grew dramatically year on year. It has caused various problems such as damaging physical and mental health of college students and ruining their social communication skills and interpersonal relationships. We came to following conclusions through this survey: 1. Smart phones have exerted great influence on students’ lives with diverse powerful functions and fast updating speed. They use phones on many occasions and mainly use phone as communicating and entertaining tools. 2. Most of students have heard of the concept ‘Phubbing’, and they think that this phenomenon will become more and more popular. According to the survey, over 70% college students said they mainly use phones for listening music, watching videos and looking through social apps, which probably is one of the reasons leading to the phenomenon of phubbing. And another 40% of students prefer face-to-face communication. Therefore, we think the negative effect of phubbing might be eased with proper guidance.

A series of nanocubes and nanorods of CeO2 and MnxCeyO (x,y = 1 or 3) oxides were prepared by the hydrothermal method. Samples as prepared were characterized by Transmission electron microscopy, X-ray diffraction, X-ray photoelectron spectroscopy and Raman spectroscopy, in order to gain a fundamental understanding of the effects of the morphology and Mn dopant on the oxygen species and active Pd2+ species in the oxidative carbonylation of phenol using Pd catalysts supported on as-prepared oxides. Although the oxygen species on supports with different morphologies varied, the catalytic performance in the oxidative carbonylation reaction did not show the significant change. Comparatively speaking, the doping of Mn is a more efficient method to control active oxygen species. It is deduced that Pd and Mn are “dopants” for pure CeO2, both of which improve the formation of oxygen vacancies that help to mitigate the reduction of active Pd species due to the strong interaction between the Pd2+ and the MnxCeyO support. Furthermore, we propose that Oβ (hydroxyl oxygen, chemisorbed oxygen or the oxygen vacancy) species acted as intermediates to lower the reduction of active palladium species by the strong interaction between the noble metal and supports, while the lattice oxygen Oα were involved in the redox cycle of Pd0/Pd2+ in the oxidative carbonylation of phenol to diphenyl carbonate. All results suggest that Mn dopants play a more important role in the activity than morphology does.

Position information is very important tactical information in large-scale joint military operations. Positioning with datalink time of arrival (TOA) measurements is a primary choice when a global navigation satellite system (GNSS) is not available, datalink members are randomly distributed, only estimates with measurements between navigation sources and positioning users may lead to a unsatisfactory accuracy, and positioning geometry of altitude is poor. A time division multiple address (TDMA) datalink cooperative navigation algorithm based on INS/JTIDS/BA is presented in this paper. The proposed algorithm is used to revise the errors of the inertial navigation system (INS), clock bias is calibrated via round-trip timing (RTT), and altitude is located with height filter. The TDMA datalink cooperative navigation algorithm estimate errors are stated with general navigation measurements, cooperative navigation measurements, and predicted states. Weighted horizontal geometric dilution of precision (WHDOP) of the proposed algorithm and the effect of the cooperative measurements on positioning accuracy is analyzed in theory. We simulate a joint tactical information distribution system (JTIDS) network with multiple members to evaluate the performance of the proposed algorithm. The simulation results show that compared to an extended Kalman filter (EKF) that processes TOA measurements sequentially and a TDMA datalink navigation algorithm without cooperative measurements, the TDMA datalink cooperative navigation algorithm performs better.

Recently, two classes of quasar samples were identified, which are promising as new cosmological probes extending to higher redshifts. The first sample uses the nonlinear relation between the ultraviolet and X-ray luminosities of quasars to derive luminosity distances, whereas the linear sizes of compact radio quasars in the second sample can serve as standardized rulers, providing angular-diameter distances. In this study, under the assumption of a flat universe, we refreshed the calibration of multiple measurements of high-redshift quasars (in the framework of a cosmological-model-independent method with the newest Hubble parameters data). Furthermore, we placed constraints on four models that characterize the cosmic equation of state ($w$). The obtained results show that: 1) the two quasar samples could provide promising complementary probes at much higher redshifts, whereas compact radio quasars perform better than ultraviolet and X-ray quasars at the current observational level; 2) strong degeneracy between the cosmic equation of state ($w$) and Hubble constant ($H_0$) is revealed, which highlights the importance of independent determination of $H_0$ from time-delay measurements of strongly lensed Quasars; 3)together with other standard ruler probes, such as baryon acoustic oscillation distance measurements, the combined QSO+BAO measurements are consistent with the standard $\Lambda$CDM model at a constant equation of state $w=-1$; 4) ranking the cosmological models, the polynomial parametrization gives a rather good fit among the four cosmic-equation-of-state models, whereas the Jassal-Bagla-Padmanabhan (JBP) parametrization is substantially penalized by the Akaike Information Criterion and Bayesian Information Criterion criterion., Comment: 15 pages, 8 figures, 2 tables, accepted for publication in SCPMA

In this paper we analyze the implications of gravitational waves (GWs) as standard sirens on the modified gravity models by using the third-generation gravitational wave detector, i.e., the Einstein Telescope. Two viable models in $f(R)$ theories within the Palatini formalism are considered in our analysis ($f_{1}(\mathcal{R})=\mathcal{R}-\frac{\beta}{\mathcal{R}^{n}}$ and $f_{2}(\mathcal{R})=\mathcal{R}+\alpha\ln{\mathcal{R}}-\beta$), with the combination of simulated GW data and the latest electromagnetic (EM) observational data (including the recently released Pantheon type Ia supernovae sample, the cosmic chronometer data, and baryon acoustic oscillation distance measurements). Our analysis reveals that the standard sirens GWs, which provide an independent and complementary alternative to current experiments, could effectively eliminate the degeneracies among parameters in the two modified gravity models. In addition, we thoroughly investigate the nature of geometrical dark energy in the modified gravity theories with the assistance of $Om(z)$ and statefinder diagnostic analysis. The present analysis makes it clear-cut that the simplest cosmological constant model is still the most preferred by the current data. However, the combination of future naturally improved GW data most recent EM observations will reveal the consistency or acknowledge the tension between the $\Lambda$CDM model and modified gravity theories., Comment: 10 pages, 11 figures, accepted for publication in ApJ

Using Born–Oppenheimer ab initio molecular dynamics (BOAIMD) simulations, the high-density water (HDW) and low-density water (LDW) structures based on SCAN meta-GGA are compared with those based on PBE GGA. Compared with Car–Parrinello ab initio molecular dynamics (CPAIMD) simulations, BOAIMD simulations can produce more accurate results because no fictitious electron mass is introduced. At each state point, our simulations continue for 100 ps after the system reached equilibrium, which is the longest ab initio simulations of liquid water reported so far and can ensure an accurate statistical average. The influence of the size effect and nuclear quantum effect on structure is not considered in the present work, but only that of two different functionals on the structure is discussed. It is found that, in HDW, just as shown using CPAIMD simulations, the SCAN-based hydrogen-bonds (HBs) are more flexible than the PBE-based ones, which makes the structure based on SCAN obviously closer to the experimental results than that based on PBE. However, it is not the case in LDW, and the difference between the results based on these two functionals is very small.

In this paper, we aim at using the DECi-hertz Interferometer Gravitational-wave Observatory (DECIGO), a future Japanese space gravitational-wave antenna sensitive to frequency range between LISA and ground-based detectors, to provide gravitational-wave constraints on the cosmic curvature at $z\sim 5$. In the framework of the well-known distance sum rule, the perfect redshift coverage of the standard sirens observed by DECIGO, compared with lensing observations including the source and lens from LSST, makes such cosmological-model-independent test more natural and general. Focusing on three kinds of spherically symmetric mass distributions for the lensing galaxies, we find that the cosmic curvature is expected to be constrained with the precision of $\Delta \Omega_K \sim 10^{-2}$ in the early universe ($z\sim5.0$), improving the sensitivity of ET constraints by about a factor of 10. However, in order to investigate this further, the mass density profiles of early-type galaxies should be properly taken into account. Specially, our analysis demonstrates the strong degeneracy between the spatial curvature and the lens parameters, especially the redshift evolution of power-law lens index parameter. When the extended power law mass density profile is assumed, the weakest constraint on the cosmic curvature can be obtained. Whereas, the addition of DECIGO to the combination of LSST+DECIGO does improve the constraint on the luminosity density slope and the anisotropy of the stellar velocity dispersion significantly. Therefore, our paper highlights the benefits of synergies between DECIGO and LSST in constraining new physics beyond the standard model, which could manifest itself through accurate determination of the cosmic curvature., Comment: 10 pages, 7 figures, accepted for publication in ApJ

The redshift distribution of galactic-scale lensing systems provides a laboratory to probe the velocity dispersion function (VDF) of early-type galaxies (ETGs) and measure the evolution of early-type galaxies at redshift z ~ 1. Through the statistical analysis of the currently largest sample of early-type galaxy gravitational lenses, we conclude that the VDF inferred solely from strong lensing systems is well consistent with the measurements of SDSS DR5 data in the local universe. In particular, our results strongly indicate a decline in the number density of lenses by a factor of two and a 20% increase in the characteristic velocity dispersion for the early-type galaxy population at z ~ 1. Such VDF evolution is in perfect agreement with the $\Lambda$CDM paradigm (i.e., the hierarchical build-up of mass structures over cosmic time) and different from "stellar mass-downsizing" evolutions obtained by many galaxy surveys. Meanwhile, we also quantitatively discuss the evolution of the VDF shape in a more complex evolution model, which reveals its strong correlation with that of the number density and velocity dispersion of early-type galaxies. Finally, we evaluate if future missions such as LSST can be sensitive enough to place the most stringent constraints on the redshift evolution of early-type galaxies, based on the redshift distribution of available gravitational lenses., Comment: 9 pages, 4 figures, accepted for publication in MNRAS

Two dimensional (2D) organic-inorganic hybrid perovskites have attracted great interest due to their tunable band gap and structural stability. In this study, biaxial strain behavior and carrier mobility of monolayers (C

Pedestrian trajectory outlier detection is of great significance in the field of video surveillance and public safety. However, due to various behavior patterns of pedestrians and complex video scenes, the trajectories obtained by real-time tracking algorithm are often complicated and accompanied by missing data. In this paper, a trajectory outlier detection algorithm based on DBSCAN and velocity entropy is proposed to detect outliers from real-time tracking trajectories. On the one hand, an improved DBSCAN algorithm is used to detect abnormal sub-trajectories, which identifies trajectory outliers with local features. On the other hand, by comparing the velocity entropy of the trajectories, trajectory outliers are detected from the overall perspective. The concept of trajectory confidence is proposed to evaluate the reliability of the results of trajectory outlier detection, thereby further reducing the false detection rate and improving accuracy. Finally, an experiment is carried out and shows that our method has a better performance than TRACLUS.

To investigate the predictive value of carotid artery calcifications (CACs) seen on dental imaging for future adverse events related to cerebrovascular and cardiovascular diseases. Electronic databases (PubMed, Embase, SCOPUS and Cochrane) and selected grey literature were searched. Outcomes included stroke, transient ischaemic attack (TIA), myocardial infarction (MI), angina, heart failure, future interventional revascularization procedures and death. Risk of bias was assessed using the Newcastle-Ottawa Scale. 5 studies were selected from 1011 records. All were of moderate to low risk of bias. Results were heterogeneous but showed that patients with CACs on panoramic radiographs (PANs) were more likely to experience strokes, TIA, MI and future revascularization procedures compared to control groups. The differences between groups were not all found to be statistically significant. Bilateral vessel-outlining CACs were an independent risk marker for future vascular events. Patients who are not currently being managed for cardiovascular risk factors should be referred for further evaluation. Those already being treated for atherosclerosis may not benefit from additional investigations. The evidence for the predictive value of CACs on PANs for adverse future vascular events is equivocal but can help to identify at-risk patients who require further evaluation. Dentists must be able to recognize CACs on PANs and make appropriate referrals for patients to be evaluated for cardiovascular risk factors, especially those who have not previously been assessed.

The preparation of quantum systems and the execution of quantum information tasks between distant users are always affected by gravitational and relativistic effects. In this work, we quantitatively analyze how the curved space-time background of the Earth affects the classical and quantum correlations between photon pairs that are initially prepared in a two-mode squeezed state. More specifically, considering the rotation of the Earth, the space-time around the Earth is described by the Kerr metric. Our results show that these state correlations, which initially increase for a specific range of satellite's orbital altitude, will gradually approach a finite value with increasing height of satellites orbit (when the special relativistic effects become relevant). More importantly, our analysis demonstrates that the changes of correlations generated by the total gravitational frequency shift could reach the level of, 10 pages, 4 figures, accepted for publication in Scientific reports

In this paper, we present a cosmological model-independent test for the cosmic opacity at high redshifts ($z\sim5$). We achieve this with the opacity-dependent luminosity distances derived from nonlinear relation between X-ray and UV emissions of quasars, combined with two types of opacity-independent luminosity distances derived from the Hubble parameter measurements and simulated gravitational wave (GW) events achievable with the Einstein Telescope (ET). In the framework of two phenomenological parameterizations adopted to describe cosmic opacity at high redshifts, our main results show that a transparent universe is supported by the current observational data at 2$\sigma$ confidence level. However, the derived value of the cosmic opacity is slightly sensitive to the parametrization of $\tau(z)$, which highlights the importance of choosing a reliable parametrization to describe the optical depth $\tau(z)$ in the early universe. Compared with the previous works, the combination of the quasar data and the $H(z)$/GW observations in similar redshift ranges provides a novel way to confirm a transparent universe ($\epsilon=0$ at higher redshifts $z\sim 5$), with an accuracy of $\Delta \epsilon\sim 10^{-2}$. More importantly, our findings indicate that a strong degeneracy between the cosmic opacity parameter and the parameters characterizing the $L_{UV}-L_X$ relation of quasars, which reinforces the necessity of proper calibration for such new type of high-redshift standard candle (in a cosmological model-independent way)., Comment: 9 figures, 9 pages, accepted for publication in ApJ

The blood-brain barrier (BBB) has an important significance in maintenance and regulation of the neural microenvironment. The occurrence of BBB disruption is the pathological change of early Alzheimer’s disease (AD). RNA-binding proteins and long non-coding RNAs are closely related to the regulation of BBB permeability. Our study was performed to demonstrate TRA2A/LINC00662/ELK4 axis that regulates BBB permeability in AD microenvironment. In Aβ1-42-incubated microvascular endothelial cells (ECs) of BBB model in vitro, TRA2A and LINC00662 were enriched. TRA2A increased the stability of LINC00662 by binding with it. The knockdown of either TRA2A or LINC00662 decreased the BBB permeability via upregulating the levels of tight junction-related proteins. ELK4 was downregulated in BBB model in vitro in AD microenvironment. LINC00662 mediated the degradation of ELK4 mRNA by SMD pathway. The downregulated ELK4 increased the permeability of BTB by inducing the tight junction-related proteins. TRA2A/LINC00662/ELK4 axis is important in the regulation of BBB permeability in AD microenvironment, which would be a new molecular target for AD treatment.

Feeding is an important and also a heavy work in river crab farming, uniform feeding is necessary for raising river crab on the whole pond. The overall scheme of automatic bait casting system carried by paddlewheel catamaran is proposed based on RTK-GPS navigation positioning device. The feeding device equipped with the controllable flow velocity of bait feeder, distance adjustable thrower and bait weight measurable device which could perform variable feeding is designed to solve the problem of nonuniform distribution of the feed. The hardware and software system of automatic feeding device are designed. Then the calculation and simulation for the modeling of the feeding device are pefromed. The test results show that the system linear track positioning accuracy is less than 30 cm, and automatic continuous feeding speed is up to 240 m2/min. The results of this study provide technology reference for further study of automatic uniform feeding on the whole pond in river crab aquaculture.

Background Jixi is a typical mining city in China that has undergone dramatic changes in its land-use pattern of mining areas over the development of its coal resources. The impacts of coal mining activities have greatly affected the regional land surface temperature and ecological system. Methods The Landsat 8 Operational Land Imager (OLI) data from 2015 and 2019 were used from the Jiguan, Didao, and Chengzihe District of Jixi in Heilongjiang, China as the study area. The calculations to determine the land-use classification, vegetation coverage, and land surface temperature (LST) were performed using ArcGIS10.5 and ENVI 5.3 software packages. A correlation analysis revealed the impact of land-use type, vegetation coverage, and coal mining activities on LSTs. Results The results show significant spatial differentiation in the LSTs of Jixi City. The LSTs for various land-use types were ranked from high to low as follows: mining land > construction land > grassland > cultivated land > forest land > water area. The LST was lower in areas with high vegetation coverage than in other areas. For every 0.1 increase in vegetation coverage, the LST is expected to drop by approximately 0.75 °C. An analysis of mining land patches indicates that the patch area of mining lands has a significant positive correlation with both the average and maximum patch temperatures. The average patch temperature shows a logarithmic increase with the growth of the patch area, and within 200,000 m2, the average patch temperature increases significantly. The maximum patch temperature shows a linear increase with the patch area growth, and for every 100,000 m2 increase in the patch area of mining lands, the maximum patch temperature increases by approximately 0.81 °C. The higher the average patch temperature of mining land, the higher the temperature in its buffer zone, and the greater its influence scope. This study provides a useful reference for exploring the warming effects caused by coal mining activities and the definition of its influence scope.

We introduce the principle and applications of one-photon absorption (OPA) and two-photon absorption (TPA) controlled by external electric fields. The physical mechanism of OPA and TPA are firstly introduced, which can visually promote thoroughly understanding of principle and physical analysis. Secondly, the applications of different molecules in OPA and TPA with and without external electric field are introduced in detail. The effect of the external electric field on the charge transfer during the absorption process is also exemplified. Furthermore, the external electric field on the molecular orbital wave function is visualized through the charge transfer process in the excited state transitions. The purpose of this review is to deepen the understanding of the types of charge transfer under linear and non-linear absorption in different systems.