CHALLENGES OF CONTROL DESIGN FOR PRECISION SERVO SYSTEM WITH APPLICATION ON HARD DISK DRIVE

Ph.DDOCTOR OF PHILOSOPH

Designing Two-dimensional Electronic Business-to-Consumer Models’ Map by Fuzzy Delphi Panel

Various electronic business-to-consumer models have been presented during the past years with different classifications. Each of these models has different dimensions. This paper uses expert knowledge to identify two key dimensions of business to customer models. Each researcher has his own list of business-to-consumer models, and there are differences in the existing lists. In this paper, some appropriate models are identified through interview with experts and fuzzy Delphi method for launching a business. The positions of these models are determined in terms of identified aspects then. Based on the obtained results, ten electronic business-to-consumer models were specified and the dimensions of the type of product and the type of financial relationship with the customer were determined to provide two-dimensional map. Then using fuzzy Delphi method, the position of these models in two-dimensional map was identified

Relationship of serum magnesium and vitamin d levels in a nationally-representative sample of iranian adolescents: The CASPIAN-III study

Background: This study aims to assess the relationship of serum Mg and vitamin D levels in a nationally-representative sample of Iranian adolescents. Methods: The study participants consisted of 330 students, aged range from 10 to 18 years, consisting of an equal number of individuals with and without hypovitaminosis D. The correlation between serum 25 hydroxy vitamin D (25(OH) D) and magnesium (Mg) concentrations was determined. Results: The mean age of participants was 14.74 ± 2.587 years, without significant difference between those with hypovitaminosis D and those without it. The mean 25(OH) D level was 6.34 ± 1.47 ng/ml in the group with hypovitaminosis D and 39.27 ± 6.42 ng/ml in the group without it. The mean Mg level was 0.80 ± 0.23 mg/dl with lower level in the group with hypovitaminosis D than in others (0.73 ± 0.22 mg/dl vs. 0.87 ± 0.22 mg/dl, respectively) and according to t-test analysis, significant lower levels in the deficient group was observed (P = 0.0001). The linear regression analysis showed the meaningful relationship between Mg and 25(OH) D serum levels (P = 0.0001). Conclusions: Our study revealed significant associations between serum Mg and 25(OH) D levels. This finding may be of use for further studies on the prevention and management of hypovitaminosis D in children and adolescents. Further longitudinal studies shall evaluate the underlying mechanisms and the clinical significance of the current findings