61 research outputs found

    The Diphoton Excess, Low Energy Theorem and the 331 Model

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    We interpret the diphoton anomaly as a heavy scalar H3H_3 in the so-called 331 model. The scalar is responsible for breaking the SU(3)CSU(3)LU(1)XSU(3)_C\otimes SU(3)_L\otimes U(1)_X gauge symmetry down to the standard model electroweak gauge group. It mainly couples to the standard model gluons and photons through quantum loops involving heavy quarks and leptons. Those quarks and leptons, in together with the SM quarks and leptons, form the fundamental representation of the 331 model. We use low energy theorem to calculate effective coupling of H3ggH_3gg, H3γγH_3\gamma\gamma, H3ZZH_3ZZ, H3WWH_3WW and H3ZγH_3Z\gamma. The analytical results can be applied to new physics models satisfying the low energy theorem. We show that the heavy quark and lepton contribution cannot produce enough diphoton pairs. It is crucial to include the contribution of charged scalars to explain the diphoton excess. The extra neutral ZZ^\prime boson could also explain the 2 TeV diboson excess observed at the LHC Run-I.Comment: To appear in PR

    Heat stress affects tassel development and reduces the kernel number of summer maize

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    Maize grain yield is drastically reduced by heat stress (HTS) during anthesis and early grain filling. However, the mechanism of HTS in reproductive organs and kernel numbers remains poorly understood. From 2018 to 2020, two maize varieties (ND372, heat tolerant; and XY335, heat sensitive) and two temperature regimens (HTS, heat stress; and CK, natural control) were evaluated, resulting in four treatments (372CK, 372HTS, 335CK, and 335HTS). HTS was applied from the nine-leaf stage (V9) to the anthesis stage. Various morphological traits and physiological activities of the tassels, anthers, and pollen from the two varieties were evaluated to determine their correlation with kernel count. The results showed that HTS reduced the number of florets, tassel volume, and tassel length, but increased the number of tassel branches. HTS accelerates tassel degradation and reduces pollen weight, quantity, and viability. Deformation and reduction in length and volume due to HTS were observed in both the Nongda 372 (ND372) and Xianyu 335 (XY335) varieties, with the average reductions being 22.9% and 35.2%, respectively. The morphology of the anthers changed more conspicuously in XY335 maize. The number of kernels per spike was reduced in the HTS group compared with the CK group, with the ND372 and XY335 varieties showing reductions of 47.3% and 59.3%, respectively. The main factors underlying the decrease in yield caused by HTS were reductions in pollen quantity and weight, tassel rachis, and branch length. HTS had a greater effect on the anther shape, pollen viability, and phenotype of XY335 than on those of ND372. HTS had a greater impact on anther morphology, pollen viability, and the phenotype of XY335 but had no influence on the appearance or dissemination of pollen from tassel

    Association between dietary folate intake and the risk of osteoporosis in adults: a cross-sectional study

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    Abstract Background Increased intake of specific vitamins has been linked to a decreased prevalence of osteoporosis. However, the association between dietary folate intake and the risk of osteoporosis in the general population remains incompletely understood. Therefore, we aimed to determine the association between dietary folate intake and the risk of osteoporosis in the general population of the USA. Methods In this cross-sectional study, data from the National Health and Nutrition Examination Survey (2017–2020) were collected. Osteoporosis was considered to be indicated by a bone mineral density greater than 2.5 standard deviations below the mean of the young adult reference group. Dietary folate intake was measured by a 24-hour dietary recall. Multivariate logistic regression models and restricted cubic spline models were used. Results The study included 2297 participants (mean age: 63.69 ± 0.35 years), 49.92% of whom were female. In the general population, increased dietary folate intake was directly associated with a decreased risk of osteoporosis (P for trend = 0.005). In the age > 60 years and female subgroups, folate intake was inversely associated with the risk of osteoporosis (P for trend < 0.001). The dose‒response curve suggested that this association was nonlinear (P for nonlinearity = 0.015). Conclusions Our cross-sectional study provides initial insights into the inverse association between dietary folate intake and the risk of osteoporosis in the general U.S. population. Further research is needed to confirm these associations

    A kernel-based l<inf>2</inf> norm regularized least square algorithm for vehicle logo recognition

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    We consider the problem of automatically recognizing the vehicle logos from the frontal views with varying illumination, as well as certain corruption. To better address the problem, a kernel-based l2 norm regularized least square (RLS) algorithm is proposed in the paper. Kernel technique is smoothly combined with the l2 norm RLS algorithm to enhance the performance of vehicle logo recognition (VLR). As an extension, the improvement of dictionary is also considered. A simple mechanism of constructing an adaptive online dictionary has been presented and experimented. Experimental results show that our proposed algorithm outperforms the original l2 norm RLS algorithm and the l1 norm based algorithms. ? 2014 IEEE.EI631-6352014-Januar

    Effects of the Damping Parameters on the Opening and Closing Characteristics of Vent Valves

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    The main function of the vent valve is to release part of the air at the outlet of the axial compressor to prevent engine surges. The damping parameters have an important effect on the opening and closing characteristics of the vent valve. The control characteristics of each component were obtained by finite element analysis and testing. The overall model of a two-stage partial pressure vent valve was established, and the reliability of the model was verified by testing. The opening and closing characteristics of the damper valve with different damping parameters were obtained by parametric simulation. The results show that there was a pressure mutation point in the middle support pressure and the pressure in the control chamber during operation of the vent valve, which made the valve open and close quickly. The damping hole of the middle shell and the middle nozzle of the support had the greatest influence on the open-close pressure ratio. The damping hole and nozzle of the middle shell had the greatest influence on the opening and closing stability. The results are used to guide the structural design, and the analytical method provides a theoretical basis for research of the same type of valve

    Effect of Substrate Plate Heating on the Microstructure and Properties of Selective Laser Melted Al-20Si-5Fe-3Cu-1Mg Alloy

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    The Al-20Si-5Fe-3Cu-1Mg alloy was fabricated using selective laser melting (SLM). The microstructure and properties of the as-prepared SLM, post-treated SLM, and SLM with substrate plate heating are studied. The as-prepared SLM sample shows a non-uniform microstructure with four different phases: fcc-&alpha;Al, eutectic Al-Si, Al2MgSi, and &delta;-Al4FeSi2. With thermal treatment, the phases become coarser and the &delta;-Al4FeSi2 phase transforms partially to &beta;-Al5FeSi. The sample produced with SLM substrate plate heating shows a relatively uniform microstructure without a distinct difference between hatch overlaps and track cores. Room temperature compression test results show that an as-prepared SLM sample reaches a maximum strength (862 MPa) compared to the heat-treated (524 MPa) and substrate plate heated samples (474 MPa) due to the presence of fine microstructure and the internal stresses. The reduction in strength of the sample produced with substrate plate heating is due to the coarsening of the microstructure, but the plastic deformation shows an improvement (20%). The present observations suggest that substrate plate heating can be effectively employed not only to minimize the internal stresses (by impacting the cooling rate of the process) but can also be used to modulate the mechanical properties in a controlled fashion
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