Development of a novel critical nitrogen concentration-cumulative transpiration curve for optimizing nitrogen management under varying irrigation conditions in winter wheat

Accurate nitrogen(N)nutrition diagnosis is essential for improving N use efficiency in crop production.The widely used critical N(Nc)dilution curve traditionally depends solely on agronomic variables,neglecting crop water status.With three-year field experiments with winter wheat,encompassing two irrigation levels(rainfed and irrigation at jointing and anthesis)and three N levels(0,180,and 270 kg ha1),this study aims to establish a novel approach for determining the Nc dilution curve based on crop cumulative transpiration(T),providing a comprehensive analysis of the interaction between N and water availability.The Nc curves derived from both crop dry matter(DM)and T demonstrated N concentration dilution under different conditions with different parameters.The equation Nc=6.43T0.24 established a consistent relationship across varying irrigation regimes.Independent test results indicated that the nitrogen nutrition index(NNI),calculated from this curve,effectively identifies and quantifies the two sources of N deficiency:insufficient N supply in the soil and insufficient soil water concentration leading to decreased N availability for root absorption.Additionally,the NNI calculated from the Nc-DM and Nc-T curves exhibited a strong negative correlation with accumulated N deficit(Nand)and a positive correlation with relative grain yield(RGY).The NNI derived from the Nc-T curve outperformed the NNI derived from the Nc-DM curve concerning its relationship with Nand and RGY,as indicated by larger R2 values and smaller AIC.The novel Nc curve based on T serves as an effective diagnostic tool for assessing winter wheat N status,predicting grain yield,and optimizing N fertilizer management across varying irrigation conditions.These findings would provide new insights and methods to improve the simulations of water-N interaction relationship in crop growth models.

Regularity classification and corresponding analysis method requirements of horizontally curved bridges with unequal pier heights

The seismic behavior of horizontally curved bridges,particularly with unequal height piers,is more complicated than that of straight bridges due to their geometric properties.In this study,the seismic responses of several horizontally curved single-column-bent viaducts with various degrees of curvature and different pier heights have been investigated,employing three different analysis approaches:namely,modal pushover analysis,uniform load method,and nonlinear time history analysis.Considering the investigated bridge configurations and utilizing the most common regularity indices,the results indicate that viaducts with 45-degree and 90-degree deck subtended angles can be categorized as regular and moderately irregular,respectively,while the bridges with 180-degree deck subtended angle are found to be highly irregular.Furthermore,the viaducts whose pier heights are asymmetric may be considered as irregular for almost all ranges of the deck subtended angles.The effects of higher transverse and longitudinal modes are discussed and the minimum analysis requirements are identified to assess the seismic response of such bridge configurations for design purposes.Although the Regularity Indices used here are useful tools to distinguish between regular and irregular bridges,further studies are needed to improve their reliability.

Prediction of Abdominal Visceral Obesity From Body Mass Index,Waist Circumference and Waist-hip Ratio in Chinese Adults:Receiver Operating Characteristic Curves Analysis

Objective To evaluate the sensitivity and specificity of body mass index (BMI), waist circumference (WC) and waist-to-hip ratio (WHR) measurements in diagnosing abdominal visceral obesity. Methods BMI, WC, and WHR were assessed in 690 Chinese adults (305 men and 385 women) and compared with magnetic resonance imaging (MRI) measurements of abdominal visceral adipose tissue (VA). Receiver operating characteristic (ROC) curves were generated and used to determine the threshold point for each anthropometric parameter. Results 1) MRI showed that 61.7% of overweight/obese individuals (BMI≥25 kg/m2) and 14.2% of normal weight (BMI<25 kg/m2) individuals had abdominal visceral obesity (VA≥100 cm2). 2) VA was positively correlated with each anthropometric variable, of which WC showed the highest correlation (r=0.73-0.77, P<0.001). 3) The best cut-off points for assessing abdominal visceral obesity were as followed: BMI of 26 kg/m2, WC of 90 cm, and WHR of 0.93, with WC being the most sensitive and specific factor. 4) Among subjects with BMI≥28 kg/m2 or WC≥95 cm, 95% of men and 90% of women appeared to have abdominal visceral obesity. Conclusion Measurements of BMI, WC, and WHR can be used in the prediction of abdominal visceral obesity, of which WC was the one with better accuracy.

Forced Inspiratory Flow Volume Curve in Patients with Obstructive Sleep Apnea-Hypopnea Syndrome

Objective: Obstructive sleep apnea-hypopnea syndrome (OSA) is a disease of obstructive apnea or hypopnea caused by a repeated partial or complete collapse of the upper airway during sleep. The inspiratory part of the flow-volume curve (F-V curve) can be used as an auxiliary means to evaluate upper airway obstruction in adults. This study is to evaluate the ability of the F-V curve to predict the OSA and explore inspiratory indicators related to airway obstruction during sleep. Methods: There were 332 patients included in this cross-sectional study, who were accompanied by snoring, daytime sleepiness and other symptoms, with suspicion of OSA. According to the nocturnal polysomnography, the subjects were distributed into mild to moderate OSA group, severe OSA group and non-OSA group. A pulmonary function test was used to collect the subjects’ spirometry and F-V curves. Results: There was no significant difference in a variety of indices derived from the F-V curve between OSA and normal subjects, including 25% inspiratory flow rate, middle inspiratory flow rate, 75% inspiratory flow rate, peak flow rate, and forced inspiratory flow rate in the first second. The pulmonary function parameters were significantly correlated with the weight, age and sex of the subjects. Conclusion: These findings suggest that the inspiratory curve of pulmonary function cannot evaluate the upper airway abnormalities in patients with obstructive apnea-hypopnea syndrome.

The solution of minimum reliability index for modified weak point of arbitrary curved beam under pure bending

This paper is based on the fundamental loading model of pure bending and the analytical model of a circular beam element with arbitrary initial deflection. The L.W. Guo solution is modified and generalized according to the elastic theory, and the analytical solution for the stress of the beam element with arbitrary initial deflection under pure bending is derived. Using yield theory of edge strength, an expression for the safety margin of one point in the arbitrary curved beam under pure bending （ACPB） is built. This paper modifies the model for weak points of service structures and establishes a foundation for safe design and inspection of imperfect structures. Also, according to the theory of the method of advanced first-order second-moment（AFOSM） , this paper derives an expression for the reliability index of one point in ACPB. Lastly, it modifies the solution for weak points by solving the minimal reliability index.

A new method to construct reservoir capillary pressure curves using NMR log data and its application

By analyzing hundreds of capillary pressure curves, the controlling factors of shape and type of capillary pressure curves are found and a novel method is presented to construct capillary pressure curves by using reservoir permeability and a synthesized index. The accuracy of this new method is verified by mercury-injection experiments. Considering the limited quantity of capillary pressure data, a new method is developed to extract the Swanson parameter from the NMR T2 distribution and estimate reservoir permeability. Integrating with NMR total porosity, reservoir capillary pressure curves can be constructed to evaluate reservoir pore structure in the intervals with NMR log data. An in-situ example of evaluating reservoir pore structure using the capillary pressure curves by this new method is presented. The result shows that it accurately detects the change in reservoir pore structure as a function of depth.

On relationship between curve numbers and phi indices

The curve number and phi(4)-index models each provide a simple one-parameter relationship between storm-event rainfall and runoff. It is shown that the curve number and 4-index models can both be used to segregate the rainfall hyetograph into initial abstraction, retention, and runoff amounts. However, the principal advantages of the 4-index model are that both rainfall distribution and duration can be explicitly taken into account in calculating runoff, and the 4 index is more physically based than the curve number. The quantitative relationship between the curve number and the 4 index is presented and validated with field measurements. Knowing the relationship between the curve number and the 4 index is useful in that it facilitates using the extensive database of curve numbers in the more realistic 4-index model in calculating a runoff hydrograph from a given rainfall hyetograph. It is demonstrated that conventional adjustments to curve numbers can be largely explained by variations in storm duration, which suggests that variable rainfall duration can possibly be an essential factor in accounting for deviations from the median curve number of a catchment.

基于EKC&Lorenz Curve的山东省生态用地时空演变及保护区划研究

研究目的:剖析近20年山东省生态用地时空演变特点,划分不同保护区域,为编制国土资源空间规划、保护生态用地提供参考。研究方法:采用环境库兹涅兹曲线(EKC),判断全省生态用地的发展趋势;根据洛伦兹曲线(Lorenz Curve)和基尼系数(Gini)方法,描述全省生态用地的分布及其演变特征;利用地理信息系统(GIS),遥感(RS)等方法获取数据并输出计算结果。研究结果:1996年以来全省生态用地总面积减少了46.8×10~4 hm^2,减少态势具有明显的"平稳—加速—减缓"的阶段性特征;全省生态用地分布基尼系数由1996年的0.523降低为2016年的0.480,生态用地区域分布趋于均衡。研究结论:(1)随着生态文明建设和美丽中国战略的深入实施,将来有可能出现生态用地由减少到增加的拐点;(2)本文把全省划分为三类不同的保护区域,并根据不同保护区的特点提出了差别化的土地利用方向和生态保护政策。

Solution and Type Curve Analysis of Fluid Flow Model for Fractal Reservoir

Conventional pressure-transient models have been developed under the assumption of homogeneous reservoir. However, core, log and outcrop data indicate this assumption is not realistic in most cases. But in many cases, the homogeneous models are still applied to obtain an effective permeability corresponding to fictitious homogeneous reservoirs. This approach seems reasonable if the permeability variation is sufficiently small. In this paper, fractal dimension and fractal index are introduced into the seepage flow mechanism to establish the fluid flow models in fractal reservoir under three outer-boundary conditions. Exact dimensionless solutions are obtained by using the Laplace transformation assuming the well is producing at a constant rate. Combining the Stehfest’s inversion with the Vongvuthipornchai’s method, the new type curves are obtained. The sensitivities of the curve shape to fractal dimension (θ) and fractal index (d) are analyzed;the curves don’t change too much when θ is a constant and d change. For a closed reservoir, the up-curving has little to do with θ when d is a constant;but when θ is a constant, the slope of the up-curving section almost remains the same, only the pressure at the starting point decreases with the increase of d;and when d = 2 and θ = 0, the solutions and curves become those of the conventional reservoirs, the application of this solution has also been introduced at the end of this paper.

Surgical Resident Attrition and the Menninger Morale Curve

BACKGROUND: Attrition in surgical residency programs continues to be a significant challenge. Ap-proximately 20% of residents who begin a categorical surgery residency fail to complete it. A number of studies speculated reasons for this including work hours, life style, family pressures, and resident feelings of inadequacy including fear of termination. To date no research has been conducted investigating the relation-ship between resident morale and attrition. This study sought to determine if this linkage exists in surgery residents. METHODS: The Morale Assessment in General Practice Index (MAGPI) was administered to 21 PGY 1, 2, 3, and 5 surgical residents to assess level of morale. Non-parametric methods were carried out to assess if there were differences in morale among the four PGY groups. Additionally, analyses of the four factors comprising the MAGPI were also conducted. RESULTS: Although differences did not reach statis-tical significance, analysis of the data reveals that residents demonstrate different trends in their levels of morale based on the amount of time they spend in a residency and in a way that approximates the morale curve described by W. Walter Menninger, M.D. Additionally, two of the four factors comprising the MAGPI also indicate trends similar to that described by the Menninger morale curve. CONCLUSIONS: Although no statistically significant results were achieved, the data reveal trends that approximate shifts in morale similar to those described by the Menninger morale curve, with residents at the PGY 2 and 3 levels present-ing lower morale levels than at the PGY 1 and 5 levels. This may be due in part to the size of the population studied. Future research should be continued in this area with a larger sample size.

高职专科助产专业设置现状及区域差异性分析

目的分析我国高职专科助产专业设置现状及区域差异性。方法筛选2023年开设高职专科助产专业的院校,提取其专业、院校信息。同时,获取各省份地理面积、2023年各省份常住人口、出生人口数量、普通高等学校数量数据。采用描述性分析法分析我国当前高职专科助产专业设置基本情况、不同区域下我国高职专科助产专业设置现状。运用洛伦兹曲线、基尼系数和泰尔指数对高职专科助产专业布点院校分布的区域差异性进行分析。结果2023年高职专科助产专业布点院校共282所,其中280所(99.3%)开设高职专科3年制助产专业;200所(70.9%)为公办院校;259所(91.8%)为高职专科院校;93所(33.0%)为公办综合类高职专科院校。2023年我国每千万常住人口、每十万出生人口、每十万平方千米高职专科助产专业布点院校数依次为2.00所、3.13所和2.93所。2023年高职专科助产专业设置在地理面积、常住人口、出生人口维度上的基尼系数依次为0.618、0.212、0.230,总泰尔指数依次为0.319、0.042、0.041。结论高职专科助产专业学制以3年制为主,布点院校类型多样,在地理面积维度上的分布极不均衡,且分布差异主要来自地区内部。应积极推进职普融通,以提升助产专业从业人员整体学历层次;通过尽快将高职专科助产专业纳入国家控制的高职专业,健全和落实专业预警和动态调整机制等举措,科学调整、优化专业布局。

不同氮效率春玉米品种临界氮浓度稀释曲线建立与验证

采用田间定位试验,以山西省晋中地区春玉米各生育时期地上部干物质量与植株氮浓度的变化规律,建立春玉米临界氮浓度稀释曲线模型,为实现春玉米绿色增产与氮素管理提供理论依据。本研究以玉米品种‘郑单958’和‘大丰26’为试验材料,设4个施氮量处理:0 kg(N)∙hm^(−2)(N0)、120 kg(N)∙hm^(−2)(N120)、240 kg(N)∙hm^(−2)(N240)和360 kg(N)∙hm^(−2)(N360),于2014—2016年在山西农业大学东阳试验基地开展3年定位施氮试验,在春玉米拔节期(V6)、抽雄期(VT)、灌浆期(R2)和成熟期(R6)采集植株样品,分析两个春玉米品种在不同施氮量处理下地上部干物质量、籽粒产量(以下简称“产量”)和各生育时期植株氮浓度,以不同生育时期干物质累积量和植株氮浓度,建立并验证两个春玉米品种的临界氮浓度稀释曲线模型。结果表明,‘郑单958’氮素利用率高于‘大丰26’。两个春玉米品种在适宜施氮量条件下,各生育时期地上部干物质量和产量均随施氮量增加呈增加趋势,地上部干物质量在N240和N360处理间差异不显著,产量在N240处理达最大值;植物氮浓度随施氮量增加而增加,随春玉米生育进程推进与地上部干物质量呈幂指数关系。依据春玉米地上部干物质量(Md)与其对应的植株氮浓度(CN)变化关系,建立两个春玉米品种的临界氮浓度稀释曲线模型:‘郑单958’CN=30.457Md−0.292,‘大丰26’CN=33.249Md−0.333。相比‘大丰26’的模型参数,‘郑单958’的模型参数a降低8.40%,参数b降低12.31%;‘郑单958’和‘大丰26’模型均方根误差(RMSE)分别为1.71 g∙kg^(−1)和1.54 g∙kg^(−1),标准化均方根误差(n-RMSE)分别为9.25%和8.27%,表明模型稳定性较好。氮营养指数在同一生育时期随施氮量增加呈上升趋势,随生育时期推进呈先增加后降低趋势,与各生育时期的相对干物质量呈显著线性相关,与相对产量呈显著的一元二次曲线关系。本研究建立的晋中地区两个春玉米品种临界氮浓度稀释曲线模型及各生育时期氮营养指数,可用于春玉米生育时期营养状况的诊断和评估,结合施氮量与产量的关系,推荐该试验区域‘郑单958’施氮量为189.16~224.08 kg∙hm^(−2),‘大丰26’施氮量为199.72~214.67 kg∙hm^(−2)。

一种新型结构与保温一体化复合墙板节点试验

为解决复合墙板节点常见的保温板易燃、易脱落等棘手问题,并使其抗震性能良好。给出了一种新型的结构与保温一体化陶粒混凝土T型复合墙板节点。该复合墙板节点具有夹芯独特构造优势,主要表现在绿色节能,轻质高强,力学性能好,保温系统连接可靠,还能杜绝火灾的发生。通过对T型复合墙板节点进行抗震试验,分别研究了其滞回性能、破坏机理、承载及变形能力、延性、耗能、损伤等。结果表明:一体化复合墙板节点的破坏顺序为腹板-翼缘-节点核心区;薄弱位置主要发生在腹板脚部,混凝土被拉裂或压碎,钢筋被拉长或压弯等;节点核心区受力相对良好,安全储备充足;符合“强节点,弱构件”设计要求和墙板革新发展政策。延性系数大于3,墙板节点安全性能良好。通过损伤指标评估分析,了解了试件各阶段工作状态。

基于图形复杂度的空间矢量数据划分和索引技术

矢量空间数据的划分存在计算性能及跨区域的问题。基于空间位置的划分虽可满足空间索引和快速查询的需求,但难以实现并行空间分析的计算负载均衡。本文提出了一种基于图形复杂度的空间矢量数据划分和索引技术,该技术基于图形复杂度,结合Hilbert空间填充曲线进行矢量数据划分,并采用R树建立分布式索引,不仅提升了数据访问速度,还解决了数据倾斜导致的计算失衡问题,为矢量空间计算任务的负载均衡提供了更优支持。

隧道纵向地震易损性分析

为研究隧道纵向抗震性能,使用改进的地基梁-弹簧非线性分析模型计算隧道纵向地震响应,其中采用PQ-Fiber纤维梁模型模拟隧道纵向的非线性行为,并施加弯矩来考虑隧道与场地之间的切向相互作用。随后,将基于增量动力分析(IDA)方法的结构地震易损性分析方法应用于隧道结构,探究适用于隧道结构的地震动强度指标(IM)。选取12条近场地震记录,用于IDA分析隧道纵向的抗震性能水平。将概率地震需求模型与工程需求参数相结合,建立结构的地震易损性曲线。结果表明,峰值速度(PGV)是适用于隧道纵向抗震性能的地震动强度指标;场地类型对隧道纵向损伤程度的影响最为深远,其中Ⅰ类场地在地震作用下损伤概率最大。此外,将计算所得易损性曲线与经验易损性曲线和横向易损性曲线进行对比分析,验证了模型的可行性,为隧道结构的抗震设计提供了一定的参考。

南水北调西线工程上线水源区大型底栖动物群落结构及环境驱动因子

为评估南水北调西线工程上线水源区大型底栖动物群落结构及环境驱动因子,于2022年7月(汛期)和11月(非汛期)开展监测采样工作。采用生物多样性指数和丰度-生物量比较曲线(ABC曲线)作为大型底栖动物群落特征参数,分析大型底栖动物群落在水源区的结构,并对其进行多元排序和Pearson相关性分析。结果表明:共采集45种大型底栖动物,隶属于4门5纲10目32科44属,其中优势种8种,所有优势物种出现频率均大于50%,水源区大型底栖动物群落结构一致性较高;水源区Margalef丰富度指数、Shannon-Wiener多样性指数和Pielou均匀度指数均值分别为4.01、1.68、0.61;多数采样区域大型底栖动物的ABC曲线呈纠缠态势,其丰度和生物量累积百分比的差值面积在0附近波动,群落以小个头物种为主;优势种以耐污值低的敏感种类为主,说明河流几乎不受污染,水体清洁;pH值是影响水源区大型底栖动物群落结构的主要环境驱动因子。

2011-2021年宁夏护理人力资源配置公平性分析

目的分析2011-2021年宁夏护理人力资源配置现状,为合理分配卫生资源提供有益参考。方法运用洛伦兹曲线、基尼系数和泰尔指数3个卫生经济学指标,评估宁夏护理人力资源配置的公平性。结果宁夏护理人力资源实现稳步增长,基尼系数和泰尔指数整体呈减小趋势,泰尔指数组间贡献率高于组内贡献率。结论宁夏护理人力资源配置逐年改善,但仍存在不公平现象,以人口分布为基础的公平性较按地理面积分布更为优越,各城市间的不平等是影响护理人力资源配置公平性的主要因素。

COVID-19对太湖重金属污染及水生生态风险的影响

自COVID-19爆发以来,人类生活和经济受到很大负面影响,但同时疫情期间自然环境得到一定改善.为探究COVID-19管控对太湖重金属污染和水生生态风险的影响,将疫情期间(2021.6—2021.7)和爆发前(2019.9—2020.1)太湖重金属污染和水生生态风险进行对比分析,并通过PCAAPCS-MLR(主成分-绝对主因子分析-多元线性回归受体模型)对重金属进行定量源解析.结果表明,疫情期间太湖重金属污染水平和对水生生物的生态风险皆显著降低,降幅分别为39.9%—92.8%和0.19%—87.66%.整体水质优良比例提升了33.65%.重金属中受影响最大的元素为铜和铬.定量源解析结果表明,工业源对铜和铬的贡献率分别为79.75%和84.26%,疫情期间工业活动的减少是太湖重金属污染和生态风险降低的主要原因.为更好地管控太湖重金属污染和保护太湖水生生物,建议优先监管太湖周边电镀、冶炼和化学三大工业企业铜和铬的排放.

山东烟区烤烟地上部临界氮稀释曲线的构建与营养诊断

为建立山东烟区烤烟地上部临界氮稀释曲线,探讨以氮素营养指数诊断烤烟氮素营养状况的可行性,优化烤烟氮素管理,田间设置6个氮肥用量,分析其对移栽后烤烟地上部干物质积累量和氮浓度的影响,并通过烤烟氮营养指数判断烟株氮素营养的丰缺情况。结果表明,随着施氮量增加,各取样时期烤烟干物质积累量均表现为先增加后稳定的趋势,不同施肥处理烤烟地上部干物质积累量差异显著;随着烤烟地上部干物质积累量的增加,不同施肥处理烤烟地上部氮浓度均逐渐降低;烤烟地上部临界氮浓度和干物质积累量符合幂函数关系,以地上部干物质积累量为驱动变量的临界氮稀释曲线为Nc=2.25×DM-0.13,其决定系数R2为0.72(p<0.05);不同氮肥处理氮营养指数(NNI)均在一定程度上呈现波动性,移栽后随时间增长呈现先上升后下降趋势,根据临界氮稀释曲线计算氮营养指数(NNI)判定烤烟氮营养状况,氮肥施用量90 kg/hm^(2)时氮营养状况较好。山东烟区烤烟地上部临界氮稀释曲线方程为Nc=2.25×DM-0.13,通过烤烟地上部临界氮稀释曲线与氮营养指数能够评价山东烟区烤烟氮营养状况,研究结果表明该试验地点适宜的氮肥施用量在90 kg/hm^(2)左右。

五品系尼罗罗非鱼对自然慢性低温胁迫的生理响应

为筛选出耐低温性能较好的尼罗罗非鱼(Oreochromis niloticus)品系,本研究以尼罗罗非鱼埃及品系(NE品系)、埃及尼罗抗逆品系(NER品系)、湘湖品系(NX品系)、新吉富(NNG品系)和吉富品系(NG品系)为研究对象,采用从最适生长温度28℃自然降温到死亡临界温度11℃的方法,分别测定它们在两个温度条件下血液生化和酶类指标的变化;当水温降到11℃后,连续观察一周,统计每种尼罗罗非鱼的存活率,绘制Kaplan-Meier曲线,比较5个品系尼罗罗非鱼的耐寒性能差异。结果显示,NER品系的存活率最高;NX品系和NER品系葡萄糖水平极显著升高,NER品系和NG品系总蛋白水平极显著降低,而白蛋白/球蛋白的值均没有显著性变化;超氧化物歧化酶、溶菌酶及乳酸脱氢酶活性均显著或极显著升高,但NER品系的乳酸脱氢酶活性升高程度最低;同时NX品系、NG品系、NE品系和NG品系的丙氨酸氨基转移酶和天门冬氨酸氨基转移酶水平均极显著增高,但NER品系的丙氨酸氨基转移酶水平没有显著性变化,其天门冬氨酸氨基转移酶水平只是显著增高。上述结果表明5个品系尼罗罗非鱼能一定程度抵御低温对机体带来的损伤,适应慢性自然降温,但NER品系存活率最高,肝功能和肌肉受损程度相对最小,在5个品系尼罗罗非鱼中耐寒性能最强。