我国劳动者教育收益率的发展趋势与城乡差异

本研究使用中国综合社会调查(CGSS)近20年66087个调查样本,分城乡各40多个年龄组别,较全面地评估了中国农村劳动人口的教育收益率的总体水平及其变化趋势,并将其与城镇同龄人口进行了比较。研究发现:按照2002年不变价格计算的城镇样本平均年收入为19055元,比农村样本高出85.4%。城乡分组回归的结果显示,农村劳动者的教育收益率为11%,约为城镇劳动者教育收益率(20.1%)的一半。长期以来,中国城镇劳动者的教育收益率高于农村劳动者的教育收益率。进入新世纪以后,教育收益率的城乡差别经历“先拉大,后缩小”的历史过程。教育程度可解释其中10-30%的差异,本研究显示,在2012年之前中国城乡教育收益率的确在6-10%之间波动,和较多学者的研究结论类似。与许多研究结论不同,中国教育收益率并未出现下降趋势或出现拐点。近10年来中国城乡教育收益率出现大幅提升,2012年之后城镇户籍人口在20-30%之间,农村户籍人口则在10-20%之间,城乡教育收益率逐年爬升。为了克服数据的同源性问题,利用中国社会状况综合调查数据(CSS)对部分研究结论重新检验,所得结论具有稳健性。

Flavonol synthase gene MsFLS13 regulates saline-alkali stress tolerance in alfalfa

Alfalfa(Medicago sativa L.) is one of the most extensively grown leguminous forage worldwide.Environmental saline-alkali stress significantly influences the growth,development,and yield of alfalfa,posing a threat to its agricultural production.However,little is known about the potential mechanisms by which alfalfa responds to saline-alkali stress.Here,we investigated these mechanisms by cloning a saline-alkali-induced flavonol synthase gene(Ms FLS13) from alfalfa,which was previously reported to be significantly upregulated under saline-alkali stress,and examining its function in the saline-alkali response.Overexpression of Ms FLS13 in alfalfa promoted plant tolerance to saline-alkali stress by enhancing flavonol accumulation,antioxidant capacity,osmotic balance,and photosynthetic efficiency.Conversely,Ms FLS13 inhibition using RNA interference reduced flavonol synthase activity and inhibited hairy root growth under saline-alkali stress.Yeast one-hybrid and dual-luciferase reporter assays indicated that the R2R3-MYB Ms MYB12 transcription factor activates Ms FLS13 expression by binding to the MBS motif in the Ms FLS13 promoter.Further analysis revealed that abscisic acid mediates the salinealkali stress response partially by inducing Ms MYB12 and Ms FLS13 expression,which consequently increases flavonol levels and maintains antioxidant homeostasis in alfalfa.Collectively,our findings highlight the crucial role of Ms FLS13 in alfalfa in response to saline-alkali stress and provide a novel genetic resource for creating saline-alkali-resistant alfalfa through genetic engineering.

Association of glycosylated hemoglobin level with lipid ratio and individual lipids in type 2 diabetic patients

Objective:To study the correlation of lipid ratios and individual lipid indexes of patients with type 2 diabetes with glycosylated hemoglobin(HbA1c).Methods:Samples were collected from 128 type 2 diabetic patients（aged 19-90 years;male 72,female 56）.The sera were analyzed for HbA1c,total cholesterol（TC）,triglycerides（TG）,high-density lipoprotein cholesterol（HDL-C） and low-density lipoprotein cholesterol（LDL-C）.According to the HbA1e level,the patients were divided into three groups,group A(HbA?【7%,n=31),group B(7%【HbA1c【10%,n=48),and group C(HbA1c】10%,n=49).The correlation of HbA1cwith lipid ratios & individual lipid indexes were analyzed.Results:With the increased level of HbA（1c）,LDL-C had a significantly increasing trend（P【0.05）;whereas TC went up with the increased HbA（1c）,without any significant differences between three groups.There was no significant correlation between HbA1c and TG or HDL-C. With the increased level of HbA1c,TC/HDL-C,LDL-C/HDL-C ratios were gradually increased, with significant differences among groups（P【0.05）.The lipid ratios,especially LDL-C/HDL-C ratio was more susceptible to impaired lipid metabolism in T2DM patients than individual lipid. Conclusions:LDL-C/HDL-C ratio is helpful in assessing and reducing the risk of cardiovascular disease caused by impaired lipid metabolism in type 2 diabetic patients.

Dynamic evaluation of land productivity in China

For making rational and scientific land-use planning,an inventory indicator of land productivity subject to biophysical limitations and human disturbance is required.This study introduces agricultural land productivity(ALP)as the dynamic indicator to measure land productivity,involving factors that affect agricultural production,such as characteristics of climate,soil,and terrain.As a case study of this dynamic indicator,ALP was estimated at county level and aggregated into provincial level in the whole of China.The result shows that ALP increased during 2000-2010 in China,and the ratios of ALP to the actual grain yield were 65.40%and 66.38%in the years 2000 and 2005,respectively.The ALP is an effective dynamic indicator to estimate the land productivity and to represent the basic conditions about the supply of water,energy,nutrients,and the physical basis for plant growth,as well as the local input.ALP estimation could provide supporting information for policy-making about land production planning and land-use management.

Genome-wide signatures of the geographic expansion and breeding of soybean

Soybean is a leguminous crop that provides oil and protein. Exploring the genomic signatures of soybean evolution is crucial for breeding varieties with improved adaptability to environmental extremes. We analyzed the genome sequences of 2,214 soybeans and proposed a soybean evolutionary route, i.e., the expansion of annual wild soybean(Glycine soja Sieb. & Zucc.) from southern China and its domestication in central China, followed by the expansion and local breeding selection of its landraces(G. max(L.) Merr.). We observed that the genetic introgression in soybean landraces was mostly derived from sympatric rather than allopatric wild populations during the geographic expansion. Soybean expansion and breeding were accompanied by the positive selection of flowering time genes, including GmSPA3c. Our study sheds light on the evolutionary history of soybean and provides valuable genetic resources for its future breeding.

A novel secreted protein, NISP1, is phosphorylated by soybean Nodulation Receptor Kinase to promote nodule symbiosis

Nodulation Receptor Kinase(NORK) functions as a co-receptor of Nod factor receptors to mediate rhizobial symbiosis in legumes, but its direct phosphorylation substrates that positively mediate root nodulation remain to be fully identified.Here, we identified a GmNORK-Interacting Small Protein(GmNISP1) that functions as a phosphorylation target of GmNORK to promote soybean nodulation. GmNORKα directly interacted with and phosphorylated GmNISP1. Transcription of GmNISP1 was strongly induced after rhizobial infection in soybean roots and nodules. GmNISP1 encodes a peptide containing 90 amino acids with a “DY” consensus motif at its N-terminus.GmNISP1 protein was detected to be present in the apoplastic space. Phosphorylation of GmNISP1 by GmNORKα could enhance its secretion into the apoplast. Pretreatment with either purified GmNISP1 or phosphorylation-mimic GmNISP1~(12D) on the roots could significantly increase nodule numbers compared with the treatment with phosphorylation-inactive GmNISP1~(12A).The data suggested a model that soybean GmNORK phosphorylates GmNISP1 to promote its secretion into the apoplast, which might function as a potential peptide hormone to promote root nodulation.

Solvothermal-assisted liquid-phase exfoliation of large size and high quality black phosphorus

Black phosphorus(BP),especially for BP nanosheets,with unique layered structure among two dimensional(2D)materials has attracted much attention due to its outstanding physical properties,such as ultra-high mobility,in-plane anisotropic properties.However,the small horizontal-size of reported BP limits its applications in the integrated circuit or some functional devices.In this work,a solvothermalassisted liquid-phase exfoliation technique is firstly employed for preparing large size and high-quality BP nanosheets.In the high-polar acetonitrile solvent,solvothermal treatment weakens the Van der Waals forces of block BP.Together with the subsequently ultrasonic processing,effective exfoliation of large size and high-quality BP nanosheets are realized.The TEM,AFM and Raman results indicate that the prepared BP nanosheets are high quality with an average thickness of about 2 nm,and the horizontalsize is up to 10μm.This facile and effective method for exfoliated BP nanosheets provides a promising strategy for the exfoliation of other 2D materials.

Dependence of Plastic Stability on 3D Interface Layer in Nanolaminated Materials

The nanolaminated materials generally exhibit poor plasticity due to the fast onset of shear instability.Engineering interface structure is an eff ective approach for enhancing plasticity via postponing or suppressing the shear instability.Here,we introduce 4 nm thick CuNb 3D amorphous interface layers and Nb 3D crystalline interface layers in Cu nanolaminated materials,respectively.In situ micro-pillar compression tests show that samples with crystalline interface layers exhibit shear instability,while the samples with amorphous interface layers display uniform deformation.Since the plastic deformation of the singlecrystal crystalline interface layer is anisotropic,except for well-aligned slip systems,dislocations on other slip systems have a poor ability to transmit the 3D crystalline interface layer,leading to localized dislocations pileups and shear instability.In contrast,the amorphous interface layer which is plastically isotropic accommodates dislocations from arbitrary slip systems of the matrix,which can alleviate the stress concentrations at the interface,and thus suppresses the shear instability.

Estimation of solid concentration in solid-liquid two-phase flow in horizontal pipeline using inverse-problem approach

In this study,an inverse-problem method was applied to estimate the solid concentration in a solid-liquid two-phase flow.An algebraic slip mixture model was introduced to solve the forward problem of solid-liquid convective heat transfer.The time-average conservation equations of mass,momentum,energy,as well as the volume fraction equation were computed in a computational fluid dynamics(CFD)simulation.The solid concentration in the CFD model was controlled using an external program that included the inversion iteration,and an optimal estimation was performed via experimental measurements.Experiments using a fly-ash-water mixture and sand-water mixture with different solid concentrations in a horizontal pipeline were conducted to verify the accuracy of the inverse-problem method.The estimated results were rectified using a method based on the relationship between the estimated results and estimation error;consequently,the accuracy of the corrected inversion results improved significantly.After a verification through experiments,the inverse-problem method was concluded to be feasible for predicting the solid concentration,as the estimation error of the corrected results was within 7%for all experimental samples for a solid concentration of less than 50%.The inverse-problem method is expected to provide accurate predictions of the solid concentration in solid-liquid two-phase flow systems.

Computational Investigation of the Interaction Between Hydrogen Atoms and an Intense Circularly Polarized Laser Field

The study of interactions between a high-power laser and atoms has been one of the fundamental and interesting topics in strong field physics for decades.Based on a nonperturbativemodel,ten years ago,we developed a set of programs to facilitate the study of interactions between a circularly polarized laser and atomic hydrogen.These programs included only contribution from the bound states of the hydrogen atom.However,as the laser intensity increases,contribution from continuum states to the excitation and ionization processes becomes larger and can no longer be neglected.Furthermore,because the original code is not able to add this contribution directly due to its many disadvantages,a major upgrade of the code is required before including the contribution from continuum states in future.In this paper,first we deduce some important formulas for contribution of continuum states and present modifications and tests for the upgraded code in detail.Second we show some comparisons among new results,old results from the original codes and the available experimental data.Overall the new result agrees with experimental data well.Last we present our calculation of above-threshold ionization(ATI)rate and compare it with a pertubative calculation.The comparison shows that our nonperturbative calculation can also produce ATI peak suppression.

Nomogram to Predict Prognosis of Patients with Gastric Cancer after Radical Gastrectomy

Objective To establish an effective prognostic nomogram for patients with gastric cancer after radical gastrectomy.Methods In the present study,we retrospectively analyzed the records of 1635 patients with gastric cancer treated at Changhai Hospital from January 2014 to December 2019.Final independent prognostic factors of overall survival to build a nomogram were screened using univariate and multivariate analyses.The predictive accuracy and discriminating ability of the nomogram were determined using the concordance index(C-index)and calibration curves.The results were validated using bootstrap resampling of 701 patients.The survival curves for low-,middle-,and high-risk patients were used to evaluate the accuracy of the nomogram.Results Multivariate analysis of the primary cohort revealed independent factors for survival as follows:age,sex,body mass index(BMI),depth of tumor invasion(T),lymph node metastasis(N),perineural invasion(PNI),tumor deposits,Alpha fetoprotein(AFP),and lactate dehydrogenase(LDH).Combining these predictors in the nomogram achieved powerful prognostic ability in the training and test sets.The C-index of the training set was 0.772(95%CI,0.748 to 0.796)compared with the C-index values of the AJCC 8^(th)(0.718),T(0.683),N(0.726)and that of the testing set(0.726[95%CI,0.684 to 0.767]),which were significant higher than the C-index values of the TNM system.The calibration curve for probability of survival showed good consistency between predictions made using nomogram compared with actual observations.The survival curves showed significant differences between-high,middle-,and low-risk groups.Conclusion We constructed a more accurate and comprehensive nomogram to predict the prognosis of gastric cancer after surgery,which may serve as a potential tool to guide personalized treatment.