Effects of low sample mean values and small sample size on the estimation of the fixed dispersion parameter of Poisson-gamma models for modeling motor vehicle crashes: A Bayesian perspective

2008 ◽  
Vol 46 (5) ◽  
pp. 751-770 ◽  
Author(s):  
Dominique Lord ◽  
Luis F. Miranda-Moreno
Author(s):  
Hayder Abdallah Hashim ◽  
Najah AL-Sayed ◽  
Ayah AL-Qaisi

Aims: The aims of this study were to introduce cephalometric norms for Qatari females and compare the result with previous published reports. Material and method: The sample consisted of 57 cephalographs with age range 18 to 25 years old. All subjects satisfied the criteria of selection. Cephalometric measurements of Qatari females were then compared with Eastman Standard norms and Arabs studies as well as reports conducted among Oriental and Black races. Results: The result indicates that Qatari females presented with higher mean values of sagittal and vertical relationship compared to Caucasian cephalometric norms. In terms of dental variables proclined upper and lower incisors in relation to their dental bases, and a reduction in inter-incisal angle. The soft tissue variables indicate that the lips were slightly protrusive in relation to Rickett’s esthetic line, and the nasolabial angle was less obtuse. The bimaxillary proclination and protrusion of the upper and lower incisors were existed in all Arab populations as well as in Black and Oriental races whereas the Caucasian had retrusive dentition. Conclusion: Due to limitation of the present study, it is difficult to draw a solid conclusion due to small sample size.  Hence, large sample size is recommended for both sexes in order to establish cephalometric norms which will be of great help not only to the orthodontist but also to the oral and maxillofacial surgeon as well as the pedodontist.


Biometrics ◽  
2006 ◽  
Vol 62 (3) ◽  
pp. 877-885 ◽  
Author(s):  
Yujun Wu ◽  
Marc G. Genton ◽  
Leonard A. Stefanski

2020 ◽  
Vol 21 ◽  
Author(s):  
Roberto Gabbiadini ◽  
Eirini Zacharopoulou ◽  
Federica Furfaro ◽  
Vincenzo Craviotto ◽  
Alessandra Zilli ◽  
...  

Background: Intestinal fibrosis and subsequent strictures represent an important burden in inflammatory bowel disease (IBD). The detection and evaluation of the degree of fibrosis in stricturing Crohn’s disease (CD) is important to address the best therapeutic strategy (medical anti-inflammatory therapy, endoscopic dilation, surgery). Ultrasound elastography (USE) is a non-invasive technique that has been proposed in the field of IBD for evaluating intestinal stiffness as a biomarker of intestinal fibrosis. Objective: The aim of this review is to discuss the ability and current role of ultrasound elastography in the assessment of intestinal fibrosis. Results and Conclusion: Data on USE in IBD are provided by pilot and proof-of-concept studies with small sample size. The first type of USE investigated was strain elastography, while shear wave elastography has been introduced lately. Despite the heterogeneity of the methods of the studies, USE has been proven to be able to assess intestinal fibrosis in patients with stricturing CD. However, before introducing this technique in current practice, further studies with larger sample size and homogeneous parameters, testing reproducibility, and identification of validated cut-off values are needed.


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