Record values from a family of J-shaped distributions

A family of J-shaped distributions has applications in life testing modeling. In this paper we study record values from this family of distributions. Based on lower records, recurrence relations and bounds as well as expressions for moments and product moments of record values are obtained, the maximum likelihood estimator of the shape parameter is derived and shown to be consistent, sufficient, complete and UMVU estimator. In addition, an application in reliability is given

Record values from a family of J-shaped distributions

A family of J-shaped distributions has applications in life testing modeling. In this paper we study record values from this family of distributions. Based on lower records, recurrence relations and bounds as well as expressions for moments and product moments of record values are obtained, the maximum likelihood estimator of the shape parameter is derived and shown to be consistent, sufficient, complete and UMVU estimator. In addition, an application in reliability is given

Alu-repeat Polymorphism in the Tissue Plasminogen Activator (T-PA) Gene, Seminal T-PA Concentration, and Male Fertility Impairment: A Case-control Study

Background: Tissue plasminogen activator (t-PA) is a protein involved in the fibrinolytic system that catalyzes the conversion of plasminogen into the active plasmin. The activity of t-PA is controlled by plasminogen activator inhibitor-1. t-PA has crucial functions during spermatogenesis. One polymorphism was reported for t-PA gene, either the presence of a 300-bp Alu-repeat (Alu+) or its absence (Alu−). Objective: The current work aimed at studying the association between Alu polymorphism in the t-PA gene and male infertility. Materials and Methods: Using polymerase chain reaction on genomic DNA isolated from the blood of 79 participants, a region polymorphic for Alu element insertion in t-PA gene was amplified. In addition, total t-PA concentration, plasminogen activator inhibitor-1/t-PA complex concentration, and t-PA activity in seminal plasma were measured by enzyme-linked immunosorbent assay. Results: The results indicate that the percentage of infertile participants (n = 50) who were homozygous for t-PA Alu insertion (Alu+/+), heterozygous Alu+/− or homozygous for t-PA Alu deletion (Alu−/−) did not change significantly (p = 0.43, 0.81, and 0.85, respectively) when compared with the control participants (n = 29). On the other hand, a significant decrease (p = 0.0001) of t-PA total concentration in seminal plasma was observed in the infertile group in comparison with the control group. However, the results indicate that there is no association between the t-PA Alu different genotypes and the total t-PA seminal concentration in the infertile group when compared to the control group (p = 0.63). Conclusion: Data obtained from the current study does not support an association between t-PA Alu polymorphism and t-PA seminal concentration or male infertility. Key words: Alu element, Male infertility, Semen, Spermatogenesis, t-PA