4-Chloro­phenyl 2-oxo-2H-chromene-3-carboxyl­ate

In title compound, C16H9ClO4, the coumarin ring system is approximately planar [maximum deviation = 0.056 (1) Å] and is oriented with respect to the benzene ring at an angle of 22.60 (7)°. Inter­molecular C—H⋯O hydrogen bonding is present in the crystal

Electroweak radiative corrections to the Higgs-boson production in association with Z0Z^0-boson pair at e+e−e^+ e^- colliders

We present the full ${\cal O}(\alpha_{{ew}})$ electroweak radiative corrections to the Higgs-boson production in association with $Z^0$-boson pair at an electron-positron linear collider(LC) in the standard model. We analyze the dependence of the full one-loop corrections on the Higgs-boson mass $m_{H}$ and colliding energy $\sqrt{s}$. We find that the corrections significantly suppress the Born cross section, and the ${\cal O}(\alpha_{{ew}})$ electroweak radiative corrections are generally between 1.0% and -15% in our chosen parameter space, which should be taken into consideration in the future precise experiments.Comment: 19 pages, 7 figures, to be published on Phys. ReV.

Serum 25-hydroxyvitamin D levels and the risk of idiopathic central precocious puberty in girls

Introduction: Prior studies have found inconsistent results regarding the relationship between vitamin D status and Idiopathic Central Precocious Puberty (ICPP). Objective: To assess the role of serum 25-hydroxyvitamin D (25 [OH]D) levels in ICPP development. Method: The authors retrospectively collected data from 221 girls with ICPP and 144 healthy girls between January 2017 and December 2019. The participants’ serum 25(OH)D levels were measured using an automatic chemiluminescence method, and the association between serum 25(OH)D levels and the risk of ICPP was assessed using multivariate logistic regression analysis. Odds Ratios (OR) with 95% Confidence Intervals (95% CI) were calculated as effect estimates. Results: Serum 25(OH)D levels in the ICPP group were significantly lower than those in healthy controls (p < 0.001). Multivariate analysis indicated that girls with insufficient vitamin D levels (OR = 0.201; 95% CI 0.094–0.428; p < 0.001) and sufficient vitamin D levels (OR = 0.141; 95% CI 0.053–0.375; p < 0.001) both had a lower risk of ICPP than girls with vitamin D deficiency. Moreover, the authors found that the height (p = 0.014), weight (p = 0.014), breast stage (p = 0.010), mother's height (p < 0.001), and luteinizing hormone/follicle-stimulating hormone ratio (p = 0.010) in girls with ICPP could be associated with levels of vitamin D. Conclusion: This study found that a low serum 25(OH)D level is an independent risk factor for ICPP, and several characteristics of girls with ICPP could be affected by their vitamin D status.

The Multi-Functional Modelling Shear Lag Method for Accurate Calculation of Static Response and Accordion Effect of Improved Composite Box Girders

The composite box girder with corrugated web and steel bottom plate (CW-SBS) is a kind of improved steel-concrete structures. The design of CW-SBS box girders needs the accurate method to calculate the working response and accordion effect in consideration of the self-stress equilibrium condition of shear lag warping stress and shear deformation. This study proposes the multi-functional modelling shear lag (MFMSL) method which adopts the four longitudinal displacement difference functions to model the variation of shear lag in the CW-SBS box girders with different wing slab widths and thicknesses. Therefore, MFMSL is a method to calculate the static response and accordion effect of the CW-SBS composite box girders. Structural differential equations based on the energy-variation principle present that the MFMSL method effectively improves the calculating accuracy of the CW-SBS box girder static response, which can be verified by both experimental and simulative results. Also, the MFMSL method demonstrates that the accordion effect of the CW-SBS box girder is stronger than that of the traditional composite box girder and closely relates to the load distribution. Hence, the proposed method further lays the foundation for the analysis and design of CW-SBS box girders

TetrazolateazidocopperIJII) coordination polymers: tuned synthesis, structure, and magnetic properties

As the first example of using a parent tetrazole and an azide together in preparing magnetic complexes, two novel tetrazolate-azido-bridged Cu(ii) coordination polymers, [Cu(tz)(N3)]n (1) and [Cu(tz)(N3)(NH3)2]n (2) (tz = tetrazolate), have been synthesized through the reaction of Htz, CuCl2, and NaN3 under hydrothermal conditions and in ammonia solution at room temperature, respectively. Single crystal X-ray structure analysis reveals that the two complexes possess distinct three-dimensional (3D) framework structures and can be topologically described as a 3-connected srs (SrSi2)-type net and a 4-connected cds (CdSO4)-type net, respectively. Both tetrazolate and azide groups also have different linkage modes in the two complexes. 1 contains end-on (EO) type azide bridges and 3-connected tetrazolate, while 2 possess end-to-end (EE) azide linkers and 2-coordinated tetrazolate. Magnetic measurements indicate that antiferrimagnetic interactions dominate between Cu(ii) ions in the two complexes with the corresponding magnetic coupling constant being J = -41.0 cm-1 in 1 and J = -8.62 cm-1 in 2

Stellar and AGN feedback in isolated early-type galaxies: the role in regulating star formation and ISM properties

Understanding how galaxies maintain the inefficiency of star formation with physically self-consistent models is a central problem for galaxy evolution. Although numerous theoretical models have been proposed in recent decades, the debate still exists. By means of high-resolution two-dimensional hydrodynamical simulations, we study the three feedback effects (the stellar wind heating, SNe feedback, and AGN feedback) in suppressing star formation activities on the evolution of early-type galaxies with different stellar masses. AGN feedback models are updated based on \citet{Yuan2018}. The gas sources comes exclusively from the mass losses of dying low-mass stars for most of our models. We find that SNe feedback can keep star formation at a significantly low level for low mass elliptical galaxies for a cosmological evolution time. For the high mass galaxies, AGN feedback can efficiently offset the radiative cooling and thus regulate the star formation activities. Such a suppression of star formation is extremely efficient in the inner region of the galaxies. AGB heating cannot account for this suppression for low and high mass galaxies. The X-ray temperature $T_{\rm X}$ and luminosity $L_{\rm X}$ of hot plasma can be in agreement with the observed data with the inclusion of effective feedback processes. These results thus suggest that we can use $T_{\rm X}$ and $L_{\rm X}$ to probe the role of different feedback processes. The inclusion of additional gas sources can make the mass scale between SNe and AGN feedback dominating in suppressing star formation decrease to an observationally inferred value of a few $10^{10}~M_{\odot}$.Comment: 21 pages, 15 figures, accepted for publication in Ap