Overestimation of canine albumin concentration with the bromcresol green method in heparinized plasma samples

Albumin concentrations are routinely measured in dogs with bromcresol green (BCG)-binding assays on automated chemistry analyzers. Several variables affect this assay, including the length of reaction time, sample type, and lack of specificity of BCG for albumin. We observed that albumin concentrations measured with BCG appeared higher in heparinized plasma samples in sick dogs. The objective of this study was to determine the effect of anticoagulant and assay procedure on BCG albumin concentrations in clinically ill dogs. We hypothesized that albumin concentrations would be overestimated in heparinized plasma compared with serum because of the combination of heparin and fibrinogen. Furthermore, we hypothesized that the overestimation would be influenced by assay parameters. Blood was collected from 32 clinically ill dogs into tubes containing heparin, citrate, or no anticoagulant. Citrate was chosen to assess the effect of fibrinogen in the absence of heparin. Albumin concentration was measured in all 3 sample types from each dog using 2 different BCG procedures on an automated chemistry analyzer. The BCG procedures (standard and modified) differed in the wavelengths used for absorbance readings (standard, 600/700; modified, 570/505) and the time point at which absorbance was measured (standard, 100 seconds; modified, 40 seconds). In addition, the modified method incorporated a sample blank. Globulin fractions, fibrinogen concentration, and indices of lipemia, hemolysis, and icterus were evaluated for their contribution to the overestimation of albumin concentration in heparinized plasma compared with serum samples. Albumin concentrations were significantly higher (P 相似文献   

Simulation of transpiration, drainage, N uptake, nitrate leaching, and N uptake concentration in tomato grown in open substrate

Free-drainage or “open” substrate system used for vegetable production in greenhouses is associated with appreciable NO₃⁻ leaching losses and drainage volumes. Simulation models of crop N uptake, N leaching, water use and drainage of crops in these systems will be useful for crop and water resource management, and environmental assessment. This work (i) modified the TOMGRO model to simulate N uptake for tomato grown in greenhouses in SE Spain, (ii) modified the PrHo model to simulate transpiration of tomato grown in substrate and (iii) developed an aggregated model combining TOMGRO and PrHo to calculate N uptake concentrations and drainage NO₃⁻ concentration. The component models simulate NO₃⁻-N leached by subtracting simulated N uptake from measured applied N, and drainage by subtracting simulated transpiration from measured irrigation. Three tomato crops grown sequentially in free-draining rock wool in a plastic greenhouse were used for calibration and validation. Measured daily transpiration was determined by the water balance method from daily measurements of irrigation and drainage. Measured N uptake was determined by N balance, using data of volumes and of concentrations of NO₃⁻ and NH₄⁺ in applied nutrient solution and drainage. Accuracy of the two modified component models and aggregated model was assessed by comparing simulated to measured values using linear regression analysis, comparison of slope and intercept values of regression equations, and root mean squared error (RMSE) values. For the three crops, the modified TOMGRO provided accurate simulations of cumulative crop N uptake, (RMSE = 6.4, 1.9 and 2.6% of total N uptake) and NO₃⁻-N leached (RMSE = 11.0, 10.3, and 6.1% of total NO₃⁻-N leached). The modified PrHo provided accurate simulation of cumulative transpiration (RMSE = 4.3, 1.7 and 2.4% of total transpiration) and cumulative drainage (RMSE = 13.8, 6.9, 7.4% of total drainage). For the four cumulative parameters, slopes and intercepts of the linear regressions were mostly not statistically significant (P < 0.05) from one and zero, respectively, and coefficient of determination (r²) values were 0.96-0.98. Simulated values of total drainage volumes for the three crops were +21, +1 and −13% of measured total drainage volumes. The aggregated TOMGRO-PrHo model generally provided accurate simulation of crop N uptake concentration after 30-40 days of transplanting, with an average RMSE of approximately 2 mmol L⁻¹. Simulated values of average NO₃⁻ concentration in drainage, obtained with the aggregated model, were −7, +18 and +31% of measured values.     

垂直圆盘式气吸排种器种子着地点原始误差数学模型的建立

使用气吸式播种机进行播种可大大提高作业效率,减轻劳动强度。针对目前垂直圆盘式气吸播种机在作业时存在种子着地误差较大的问题,分析其误差形成的原因与过程,建立相应的数学模型,为播种机具性能的改进提供理论依据。     

The fallacy of the missing middle: physics →…→ fisheries

In this paper I discuss some of the shortcomings of today's marine science in response to a recently published paper by Ann Gargett (1997). Three problem areas have been identified in the field linking climate forcing and fish production: First, the yet-to-be established observational proof for a relationship between the two; Second, the strongly neglected biology of organisms at evolutionary and ecological time scales; and thrird, the disregard for spatial and temporal scales in the discussion of mechanisms and supporting data.     

一种恢复渠道中线测量的快捷方法

渠道是农田水利建设的一个重要工程，渠道测量在渠道兴、改、扩建中具有重要的地位和作用。仅就施工过程中如何快捷恢复渠道中线的测量方法作了探讨，并对恢复中线的精度作了相应分析。     

农业机器人的超声波测距系统设计

设计了一种用于农业机器人的超声波测距系统;分析了系统的硬件组成和工作原理;提出了采用声速温度补偿及针对湿度、气压和硬件电路的精度等其他影响因素的误差修正因子补偿来提高测距精度的方法.实验证明:该系统能够实现对农作物的精确测距和定位, 在一定程度上辅助农业机器人的视觉系统,使其提高精度.     

吉林省农村居民消费与收入的关系分析和政策建议

消费是国民经济的重要组成部分.为此,通过对吉林省1985～2005年农村居民消费支出与农村收入的关系进行协整检验并建立误差修正模型,验证了两者之间存在的长期协整关系和短期修正关系.同时,根据分析的结果给出了提高吉林省居民消费水平的相关政策建议.     

霍尔效应测量中的系统误差及其处理

本文对霍尔效应测量中的热能流引起的不等位电势误差提出了自己的见解,然后着重研究消除系统误差的方法,并对实验结果进行了评述.     

PA序列下非参数回归函数估计的相合性

设{εi,i≥1}为PA序列，Eεi=0，supE（ε^2j）〈∞，对某个r〉2及占〉δ，supE｜εj｜^r＋δ〈∞，u（n）=O（n^（r-2）（r＋δ）/2δ，在PA序列误差下，讨论了非参数回归函数加权核估计的相合性．     

原油动态计量中流量计系数的使用方法

在原油贸易交接过程中,流量计为主要计量工具,就动态计量中流量计系数的确定及如何运用该系数计算油量进行了分析.结合实例介绍了运用误差法进行油量交接的情况,以及流量计基本误差超差时的差量处理方法.