Method comparison in the clinical laboratory

Studies comparing a new method with an established method, to assess whether the new measurements are comparable with existing ones, are frequently conducted in clinical pathology laboratories. Assessment usually involves statistical analysis of paired results from the 2 methods to objectively investigate sources of analytical error (total, random, and systematic). In this review article, the types of errors that can be assessed in performing this task are described, and a general protocol for comparison of quantitative methods is recommended. The typical protocol has 9 steps: 1) state the purpose of the experiment, 2) establish a theoretical basis for the method comparison experiment, 3) become familiar with the new method, 4) obtain estimates of random error for both methods, 5) estimate the number of samples to be included in the method comparison experiment, 6) define acceptable difference between the 2 methods, 7) measure the patient samples, 8) analyze the data, and 9) judge acceptability. The protocol includes the essential investigations and decisions needed to objectively assess the overall analytical performance of a new method compared to a reference or established method. The choice of statistical methods and recommendations of decision criteria within the stages are discussed. Use of the protocol for decision-making is exemplified by the comparison of 2 methods for measuring alanine aminotransferase activity in serum from dogs. Finally, a protocol for comparing simpler semiquantitative methods with established methods that measure on a continuous scale is suggested.     

北京市森林资源固定样地调查体系研究

结合当前北京市林业发展形势及需求,针对现有森林资源监测体系的不足,提出建立北京市森林固定样地调查体系,以完善森林资源动态监测。本文从固定样地抽样及布设、样地调查内容、数据应用等方面做出阐述,全面介绍了北京市森林固定样地调查体系的构建。     

退耕还林工程可持续发展问题研究

简要总结了我国自2002年全面启动退耕还林（草）工程以来所取得的成果．分析了还存在的工程规划不尽合理;没有建立起有效的产权制度;劣质种苗造林;未能适地适树等现象屡见不鲜;后续产业发展步履艰难等问题．为了巩固成果实现该工程的可持续发展,应采取保持政策的可持续性;政府进行宏观调控,刺激农民的参与意愿;征收生态环境补偿税;适地适树（草）提高工程质量等应对措施．     

箱线图及其在JCR网络版中的应用

JCR（期刊引证报告）是对世界权威期刊进行系统、客观评价的有效工具。基于JCR网络版影响因子数据,利用最小值、第一四分位数、中位数、第三四分位数、最大值五个统计量,按期刊所属学科领域以可视化方式直观呈现影响因子箱线图,并以类目箱线图的形式评估跨学科期刊在不同学科领域中的影响力。     

基于农户耕地规模和种子选择的小麦生产

从农户耕地规模和种子选择的视角出发,采用随机抽样的方法,对我国小麦生产大省河南省的14个县56个行政村300余户农民的进行问巷调查.在分析了小麦种植地块规模、品种数量及种子来源对小麦生产造成影响的基础上,提出从品种审定、良种补贴、保障措施及农民与土地关系等4个方面进行改革,促进小麦生产的可持续发展,以确保国家粮食安全.     

Remote sensing and forest inventories in Nordic countries – roadmap for the future

The Nordic countries have long traditions in forest inventory and remote sensing (RS). In sample-based national forest inventories (NFIs), utilization of aerial photographs started during the 1960s, satellite images during the 1980s, laser scanning during the 2000s, and photogrammetric point clouds during the 2010s. In forest management inventories (FMI), utilization of aerial photos started during the 1940s and laser scanning during the 2000s. However, so far, RS has mostly been used for map production and research rather than for estimation of regional parameters or inference on their accuracy. In recent years, the RS technology has been developing very fast. At the same time, the needs for information are constantly increasing. New technologies have created possibilities for cost-efficient production of accurate, large area forest data sets, which also will change the way forest inventories are done in the future. In this study, we analyse the state-of-the-art both in the NFIs and FMIs in the Nordic countries. We identify the benefits and drawbacks of different RS materials and data acquisition approaches with different user perspectives. Based on the analysis, we identify the needs for further development and emerging research questions. We also discuss alternatives for ownership of the data and cost-sharing between different actors in the field.     

3因素随机裂区试验设计及其统计分析

提出一种新的3因素随机裂区试验设计,给出了自由度与平方和分解方案,以及固定模型、随机模型及2种混合模型的均方构成,同时提出了随机模型误差方差计算方法。     

山地丘陵区耕作田块修筑工程设计参数及田块特征——以重庆为例

【目的】在山地丘陵区,耕作田块修筑工程的参数设计对该区域农业机械化、规模化及产业化发展起着决定性作用。但过去的研究主要集中在工程前后田块特征及土壤特性上,缺乏对其最基本工程设计参数的研究。因此,明确山地丘陵区耕作田块修筑工程参数设计的技术要点对该区域耕地资源的可持续发展有着非常重要的实践指导意义。【方法】以重庆山地丘陵区2010—2015年间实施的28个耕作田块修筑工程区为研究对象,通过开展实地调研,对山地丘陵区耕作田块修筑工程设计参数及其对耕作田块特征的影响进行了研究。【结果】(1)选址方法:地形坡度在25°以上的区域为禁止建设区,地形坡度在25°以下的区域为有条件建设区,其中,15°以下的区域为重点建设区。在地形坡度6°且集中连片面积在3.33 hm~2(50 mu)以上的区域(类型区A)重点布设条田与缓坡地;在扣除类型区A的基础上,地形坡度15°且集中连片面积在3.33 hm~2(50 mu)以上的过渡区域(类型区B),条田、梯田、梯地及缓坡地均可布设;在扣除类型区A和B的基础上,地形坡度25°且集中连片面积在3.33 hm~2(50 mu)以上的区域(类型区C)主要布设梯田与梯地。(2)工程设计参数:条田、梯田、梯地及缓坡地的田块长度宜分别设置为50—200、50—200、30—200及50—300 m;田块宽度宜分别设置为30—100、10—30、5—20及50—100 m;条田与梯田的田面坡度均为0°,梯地与缓坡地的田面坡度宜分别小于10°与6°;条田及缓坡地的田坎一般均可采用夯砌土坎,但如果其土壤特性不能够满足工程施工要求时,亦可采用条石或块石为主材进行修筑。而梯田与梯地则可分别采用浆砌条石与干砌条石,但如果区域内条石匮乏,其运输成本较高的情况下,以满足工程稳定性为前提,亦可采用浆砌块石或夯砌土坎。(3)对田块特征的影响:耕作田块修筑工程打破了原有田坎,将原本分散、细小及不规整的田块进行合并与再规划,最终组合形成面积较大的、形状规整的、分布相对集中的耕作田块。耕作田块修筑工程实施后,田块平均规模从0.23 hm~2提升为0.63 hm~2,提升了1.79倍;田块形状指数从18.02降低为10.22,降低了7.80;田块密度从7.09个/hm~2降低为3.35个/hm~2,降低了3.74个/hm~2;田块面积的Moran’s I指数从0.1937提升到0.3501,提升了0.1564。【结论】依据地形坡度与最小耕作田块修筑单元,可将山地丘陵区耕作田块修筑工程建设为条田、梯田、梯地及缓坡地4种类型,能够显著地改善山地丘陵区耕地破碎化现状,有效地促进该区域农业机械化、规模化及产业化发展,其工程设计除依据考虑地形、水文及土壤特性外,更应注重就地取材,降低建造成本。     

鲁中南山丘区坡面产流产沙与降雨关系

为探求鲁中南山丘区坡面侵蚀规律,选取山东省泰安市药乡小流域,以4个坡面径流小区的降雨、径流、泥沙实测资料为基础,探究不同措施下各小区产流产沙的差异性和导致产流的降雨量临界值,并利用相关分析方法探究径流泥沙与降雨的相关关系。结果表明:(1)导致径流产生的降雨量临界值表现为裸地农地草地,草地临界降雨量分别比梯田种植、横坡种植、裸地高0.2,2.8,3.8mm;(2)在相同的降雨条件下,各小区产流产沙均为裸地最大,其中产流量约为农地的1.3~4.3倍,约为草地的2.8倍;产沙量约为农地的3.1~10.4倍,约为草地的77.6倍;产流开始时间以裸地最早,草地最晚,二者之间相差37min,结束时间正好相反;(3)通过对不同降雨因子与产流产沙进行皮尔逊相关分析,除降雨历时(D)外,其它降雨因子均与产流、产沙量有较好相关性,其中与降雨量(P)相关性最强。