1. A novel test by combining the maximum and minimum values among a large number of dependent Z-scores with application to genome wide association study
Zhengbang Li, Sanan Qin, Qizhai Li Stat Med. 2021 May 10;40(10):2422-2434. doi: 10.1002/sim.8912. Epub 2021 Mar 4.
In this article, we propose a novel test via combining the maximum and minimum values among a large number of dependent Z-scores for testing the hypothesis with sparse signals. The proposed test employs the information about different signs of maximum and minimum Z-scores and thus power is gained. Its asymptotic null distribution is derived under the null hypothesis and some regular conditions. Extensive simulation studies are conducted to show the advantages of the proposed test by comparing with two existing ones. A real application to the lipids genome wide association study further shows its performances.
2. Maximum duration of sustained /s/ and /z/ and the s/z ratio with controlled intensity
Marylou Pausewang Gelfer, John F Pazera J Voice. 2006 Sep;20(3):369-79. doi: 10.1016/j.jvoice.2005.03.011. Epub 2005 Oct 19.
The purpose of this study was to compare maximum prolongations of controlled-intensity /s/ vs. /z/ in young healthy male and female adults and to compare the s/z ratio in young men and women. Twenty young adult men and 20 young adult women were included in this study. Participants produced 10 trials of /s/ and 10 of /z/ with a controlled intensity of 60-dB sound-pressure level (SPL). Maximum prolongations and s/z ratio were determined by three different methods: based on the longest out of 10 trials, the longest of 3 trials, and an average of the first 3 trials. Results revealed that based on averaged group data, /s/ and /z/ seemed to be prolonged for similar durations. Men consistently prolonged both phonemes significantly longer than women. There were no significant differences in s/z ratio between men and women. However, when individual data were reviewed, it seemed that some subjects consistently prolonged /s/ for a longer duration than /z/, some subjects prolonged /z/ longer than /s/, and some subjects actually produced approximately equal durations of the two phonemes. It was further noted that /s/ durations were more favorably impacted by practice than /z/ durations.
3. Z-score model of foetal ascending aorta diameter distensibility
Fuli Chen, Shi Zeng, Aijiao Yi, Lihua Chen, Dan Zhou, Yushan Liu, Longmei Yao Front Cardiovasc Med. 2022 Aug 11;9:858235. doi: 10.3389/fcvm.2022.858235. eCollection 2022.
Objective: The purpose of this study is to establish Z-scores models of normal fetal ascending aorta diameter and diameter distensibility. Methods: The maximum systolic diameter (Dmax), minimum diastolic diameter (Dmin), and diameter distensibility of the sinotubular junction were measured and taken as dependent variables in 490 normal fetuses at 18-40 gestational weeks, and gestational age (GA), biparietal diameter (BPD), and femoral length (FL) were taken as independent variables. The data were subjected to regression analysis, and the best-fitting equations for the dependent variables based on the independent variables were determined. The fitting equations were then applied to construct the Z-scores models. Results: The Dmax, Dmin and Diameter Distensibility in normal fetuses between 18 and 40 weeks of GA could be evaluated by utilizing the Z-scores models. Dmax and Dmin increased significantly with increasing GA, BPD, and FL. Diameter distensibility, assessed as (Dmax-Dmin)/Dmin, decreased significantly with increasing GA, BPD, and FL. Conclusion: The Z-scores are valuable, and can be utilized as a potent supplement to the conventional approach as they can indirectly reflect the development of fetal ascending aortic elastic property.
