Background： Measuring total serum calcium is important for the diagnosis of diseases. Currently, results from commercial kits for calcium measurement are variable. Generally, the performance of serum calcium measurem...Background： Measuring total serum calcium is important for the diagnosis of diseases. Currently, results from commercial kits for calcium measurement are variable. Generally, the performance of serum calcium measurements is monitored by external quality assessment （EQA） or proficiency testing schemes. However, the commutability of the EQA samples and calibrators is often unknown, which limits the effectiveness of EQA schemes. The aim of this study was to evaluate the bias of serum calcium measurements and the commutability of processed materials. Methods： Inductively coupled plasma mass spectrometry was applied as a comparative method, and 14 routine methods were chosen as test methods. Forty-eight serum samples from individual patients and 25 processed materials were quantified. A scatter plot was generated from patient samples, and 95% prediction intervals were calculated to evaluate the commutability of the processed materials and measurement bias at three concentration levels was used to determine the accuracy of routine assays. Results： All assays showed high precision （total coefficient of variation [CV] 〈2.26%） and correlation coefficients （r 〉 0.99）. For all assays, the mean bias for the 48 patient samples ranged from 0.13 mmol/L to 0.00 mmol/L （-5.61 0.01%）, and the ranges for the three concentrations were 0.10-0.04 mmoUL （-5.71-2.35%）, -0.14-0.01 mmol/L （-5.80-0.30%）, and -0.19-0.04 mmol/L （-6.24-1.22%）. The EQA samples, calibrators, and animal sera exhibited matrix effects in some assays; human serum pools were commutable in all assays; certificate reference materials were commutable in most assays, and only GBW09152 exhibited a matrix effect in one assay： and aqueous reference materials exhibited matrix effects in most assays. Conclusions： Biases for most assays were within the acceptable range, although the accuracy of some assays needs improvement. Human serum pools prepared from patient samples were commutable, and the other tested materials exhibited a mat展开更多
该文在奇异值矩阵分解方法的基础上,提出了一种融合景点季节演变信息的旅游推荐算法。该算法根据景点属性与季节演变之间的关联,将旅游景点的属性划分为静态方面和动态方面,并通过设计包含时间因素的动态偏置函数来刻画用户偏好与景点...该文在奇异值矩阵分解方法的基础上,提出了一种融合景点季节演变信息的旅游推荐算法。该算法根据景点属性与季节演变之间的关联,将旅游景点的属性划分为静态方面和动态方面,并通过设计包含时间因素的动态偏置函数来刻画用户偏好与景点之间的动态关联。这些静态和动态方面的信息被作为新的偏置项融入有偏奇异分解(Bias singular value decomposition,Bias SVD)模型,以改善用户对旅游景点的评分预测。标准数据集Yelp上的实验结果表明,相比于对用户签到数据无差别对待的推荐方法,该文方法在推荐精度和用户体验方面均有明显的提升。展开更多
为了研究三江源生态功能区生态约束下畜牧业技术进步偏向,本研究选取2010—2019年三江源生态功能区所辖4个州(海南、黄南、果洛、玉树4个藏族自治州)21个县为样本,采用非期望产出不可分的松弛值测算的模型(slacks based measure, SBM)...为了研究三江源生态功能区生态约束下畜牧业技术进步偏向,本研究选取2010—2019年三江源生态功能区所辖4个州(海南、黄南、果洛、玉树4个藏族自治州)21个县为样本,采用非期望产出不可分的松弛值测算的模型(slacks based measure, SBM)、曼奎斯特指数(Malmquist index, MI)和ArcGIS 10.6软件测评环境规制下生态畜牧业生产效率,分析时空变化趋势及技术进步方向。结果表明:与2010年相比,2019年三江源生态功能区全部牲畜存栏量减少13.83%,但大型牲畜存栏量反而增长14.83%。研究区域生态畜牧业全要素生产效率处于波动状态,区域间差异较大,投入型技术进步对全要素生产效率起抑制作用。纯牧区畜牧业技术进步偏向于节约劳动使用、减少大型牲畜存栏量;半农半牧区技术进步偏向于节约草场投入,存栏结构总体更偏向减少小型牲畜存栏量,均与实际牲畜存栏结构变化相违背。在考虑非期望产出不可分的情况下,投入型技术进步偏向逐渐与各地区资源禀赋不相协调,难以适应快速变化的存栏结构,抑制了生态优先的发展战略。建议以草定畜、分区规划、增加生态补偿;季节调节、良种改良、促进畜草资源空间流动;明晰产权、集聚资源、加强畜牧联合体建设。展开更多
文摘Background： Measuring total serum calcium is important for the diagnosis of diseases. Currently, results from commercial kits for calcium measurement are variable. Generally, the performance of serum calcium measurements is monitored by external quality assessment （EQA） or proficiency testing schemes. However, the commutability of the EQA samples and calibrators is often unknown, which limits the effectiveness of EQA schemes. The aim of this study was to evaluate the bias of serum calcium measurements and the commutability of processed materials. Methods： Inductively coupled plasma mass spectrometry was applied as a comparative method, and 14 routine methods were chosen as test methods. Forty-eight serum samples from individual patients and 25 processed materials were quantified. A scatter plot was generated from patient samples, and 95% prediction intervals were calculated to evaluate the commutability of the processed materials and measurement bias at three concentration levels was used to determine the accuracy of routine assays. Results： All assays showed high precision （total coefficient of variation [CV] 〈2.26%） and correlation coefficients （r 〉 0.99）. For all assays, the mean bias for the 48 patient samples ranged from 0.13 mmol/L to 0.00 mmol/L （-5.61 0.01%）, and the ranges for the three concentrations were 0.10-0.04 mmoUL （-5.71-2.35%）, -0.14-0.01 mmol/L （-5.80-0.30%）, and -0.19-0.04 mmol/L （-6.24-1.22%）. The EQA samples, calibrators, and animal sera exhibited matrix effects in some assays; human serum pools were commutable in all assays; certificate reference materials were commutable in most assays, and only GBW09152 exhibited a matrix effect in one assay： and aqueous reference materials exhibited matrix effects in most assays. Conclusions： Biases for most assays were within the acceptable range, although the accuracy of some assays needs improvement. Human serum pools prepared from patient samples were commutable, and the other tested materials exhibited a mat
文摘该文在奇异值矩阵分解方法的基础上,提出了一种融合景点季节演变信息的旅游推荐算法。该算法根据景点属性与季节演变之间的关联,将旅游景点的属性划分为静态方面和动态方面,并通过设计包含时间因素的动态偏置函数来刻画用户偏好与景点之间的动态关联。这些静态和动态方面的信息被作为新的偏置项融入有偏奇异分解(Bias singular value decomposition,Bias SVD)模型,以改善用户对旅游景点的评分预测。标准数据集Yelp上的实验结果表明,相比于对用户签到数据无差别对待的推荐方法,该文方法在推荐精度和用户体验方面均有明显的提升。
