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161.
以水溶性α.β.γ.δ—四—(4—三甲铵苯基)卟啉[T-(4-TAP)P]作显色剂,测定了食品中的痕量铜。对实验条件及共存离子的干扰进行了探讨。在乙醇介质及强酸条件下测定时,其选择性及灵敏度均有显著提高。摩尔吸收系数为4.5×10~5 1mol~(-1).cm~(-1)最小检验量为:0.14ng/cm~2,回收率为96.2~106%,变异系数为:0.46~3.6%。操作简便,结果满意。 相似文献
162.
In this paper we compare several approaches to identifying certain key respiratory control parameters relying on data normally
available from non-invasive measurements. We consider a simple model of the respiratory control system and describe issues
related to numerical estimates of key parameters involved in respiratory function such as central and peripheral control gains,
transport delay, and lung compartment volumes. The combination of model-specific structure and limited data availability influences
the parameter estimation process. Methods for studying how to improve the parameter estimation process are examined including
classical and generalized sensitivity analysis, and eigenvalue grouping. These methods are applied and compared in the context
of clinically available data. These methods are also compared in conjunction with specialized tests such as the minimally
invasive single-breath CO2 test that can improve the estimation, and the enforced fixed breathing test, which opens the control loop in the system.
The analysis shows that it is impossible to estimate central and peripheral gain simultaneously without usage of ventilation
measurement and a controlled perturbation of the respiratory system, such as the CO2 test. The numerical results are certainly model dependent, but the illustrated methods, the nature of the comparisons, and
protocols will carry over to other models and data configurations. 相似文献
163.
F E Alexander 《Statistics in medicine》1989,8(6):743-755
Day and Walter derived methods of joint maximum likelihood estimation for the sojourn time distribution and the false negative rate for a screening programme. Their methods are not directly applicable to a programme which uses alternate screening by two modalities whose sojourn times and false negative rates will differ. A modification is proposed and the results applied to data from the Edinburgh Randomised Trial of Breast Cancer Screening. This enables the effects of mammography and clinical examination to be separated. It is estimated that in a programme using both modalities 79 per cent of tumours arising in regularly screened women would be detected by screening and if the clinical examination were omitted this figure would be reduced by 5 per cent. The confidence intervals are, however, quite wide. 相似文献
164.
Marina A. Bornovalova Jennifer M. O'Donnell Jerry B. Richards C.W. Lejuez 《Pharmacology, biochemistry, and behavior》2009,93(3):258-262
Although previous studies have shown that the Balloon Analogue Risk Task (BART; [Lejuez, C.W., Read, J.P., Kahler, C.W., Richards, J.B., Ramsey, S.E., Stuart, G.L., et al. (2002). Evaluation of a Behavioral Measure of Risk Taking: The Balloon Analogue Risk Test (BART). J Exp Psychol, Appl, 8, 75-84.; Lejuez, C., Aklin, W., Jones, H., Richards, J., Strong, D., Kahler, C.W., et al. (2003a). The Balloon Analogue Risk Task (BART) Differentiates Smokers and Nonsmokers. Exp Clin Psychopharmacol, 11, 26-33.; Lejuez, C., Aklin, W., Zvolensky, M., & Pedulla, C. (2003b). Evaluation of the Balloon Analogue Risk Task (BART) as a Predictor of Adolescent Real-world Risk-taking Behaviors. J Adolesc, 26, 475-479.]) can be used to index real-world risk-taking behavior, questions remain regarding how performance on the task may vary as a function of reward/loss value and how this relationship may differ as a function of relevant personality traits. The present study examined BART score at 1, 5, and 25 cents per pump and how this relationship differed at low and high levels of impulsivity and sensation seeking. Results indicated that riskiness on the BART decreased as reward/loss magnitude increased. Further, this decrease was most prominent in those low in Impulsivity/Sensation Seeking, whereas those high in Impulsivity/Sensation Seeking were largely insensitive to variation in reward/loss magnitude. Findings are discussed in terms of sensitivity to reward and loss, and how these processes can be studied further using the BART including extensions to cognitive modeling and the measurement of neurobehavioral functioning. 相似文献
165.
目的:了解在高原环境(海拔2200m-3800m)及饮食条件下,移居高原的60岁以上的高血压患者胰岛素抵抗情况。方法:对32名移居及36名世居60岁以上1级、2级高血压患者行血压、血脂、空腹血糖及空腹胰岛素检验,应用Homa Model稳态模型分析法评估胰岛素抵抗状况。结果:移居高原的60岁以上的高血压患者由于受自然环境及饮食生活方式影响,收缩压及空腹胰岛素水平均较世居者高,出现明显胰岛素抵抗。结论:移居的高血压患者与世居者存在着胰岛素敏感性或β细胞功能的差异。 相似文献
166.
孤独症诊断访谈量表(修订本)的诊断效度及信度研究 总被引:13,自引:1,他引:12
目的:检验孤独症诊断访谈量表(修订本)的诊断效度及信度。方法:收集门诊孤独症(50例,孤独症组)及非孤独症(32例,非孤独症组)初诊病例,采用孤独症诊断访谈量表(修订本)对两组进行临床评定,评定者对诊断采用单盲控。结果:(1)诊断效度:在社会交互作用的16项中有15项(94%)、语言及交流的13项中有11项(85%)、刻板、局限、重复的兴趣与行为方式的8项中有4项(4/8)均具有诊断意义,均P<0.01。(2)诊断信度:在社会交互作用的16项中有15项(94%)、语言及交流的13项中有10项(77%)、在刻板、局限、重复的兴趣与行为方式的8项中有3项(3/8),其Kappa值均>0.677。结论:孤独症诊断访谈量表(修订本)各项目的诊断效度较好,评定者之间的一致性较高,临床适用性很强。 相似文献
167.
Laura M. Ellwein Hien T. Tran Cheryl Zapata Vera Novak Mette S. Olufsen 《Cardiovascular Engineering》2008,8(2):94-108
The complexity of mathematical models describing the cardiovascular system has grown in recent years to more accurately account
for physiological dynamics. To aid in model validation and design, classical deterministic sensitivity analysis is performed
on the cardiovascular model first presented by Olufsen, Tran, Ottesen, Ellwein, Lipsitz and Novak (J Appl Physiol 99(4):1523–1537,
2005). This model uses 11 differential state equations with 52 parameters to predict arterial blood flow and blood pressure.
The relative sensitivity solutions of the model state equations with respect to each of the parameters is calculated and a
sensitivity ranking is created for each parameter. Parameters are separated into two groups: sensitive and insensitive parameters.
Small changes in sensitive parameters have a large effect on the model solution while changes in insensitive parameters have
a negligible effect. This analysis was successfully used to reduce the effective parameter space by more than half and the
computation time by two thirds. Additionally, a simpler model was designed that retained the necessary features of the original
model but with two-thirds of the state equations and half of the model parameters. 相似文献
168.
169.
目的 试测美国人格诊断问卷 (PDQ 4 )并调查北京市中学生人格偏离的检出率及其分布。方法 以ICD 10为金标准在 10 0例人格障碍患者、91例非人格障碍的精神病患者和 10 0名正常人中计算PDQ 4的灵敏度、特异度和重测一致性 ;以现况调查分层整群抽样的方法 ,采用PDQ 4调查北京市 10 0 39名高中一年级学生。结果 PDQ 4具有高灵敏度和中等特异度 ,重测一致率为 92 .2 %。正常成人样本PDQ 4量表总分为 18.9± 9.8,男性量表总分为 2 0 .6± 10 .1,女性量表总分为 17.1±9.2 ,差异有显著性 (t=2 .0 9,P <0 .0 5 )。各年龄组量表总分差异无显著性。北京市高一学生PDQ 4量表总分为 2 5 .4± 9.6 ,明显高于正常成人样本。该人群人格偏离的检出率为 5 .6 % ;检出率男生明显高于女生 ;城区学生明显低于乡镇学生 ;市重点学生最低 ,普通中学学生最高。结论 PDQ 4 (中文版 )可以作为效度和信度较好的人格障碍筛查工具 ;北京市中学生人格偏离有性别、城乡和学校类型的差异 ,是青春期值得重视的心理发育问题。 相似文献
170.