Experimental Designs for Binary Data in Switching Measurements on Superconducting Josephson Junctions

We study the optimal design of switching measurements of small Josephson junction circuits which operate in the macroscopic quantum tunnelling regime. Starting from the D-optimality criterion we derive the optimal design for the estimation of the unknown parameters of the underlying Gumbel type distribution. As a practical method for the measurements, we propose a sequential design that combines heuristic search for initial estimates and maximum likelihood estimation. The presented design has immediate applications in the area of superconducting electronics implying faster data acquisition. The presented experimental results confirm the usefulness of the method. KEY WORDS: optimal design, D-optimality, logistic regression, complementary log-log link, quantum physics, escape measurement

Chronic inflammatory changes seen in gallbladders of patients with pancreatico-biliary malunion years after transduodenal sphincterotomy: Is it a precursor for gallbladder carcinoma?

The original publication can be found at www.springerlink.comCommon pancreaticobiliary channel malunion (PBM) is known to be associated with increased frequency of gallbladder (GB) cancer in adults. Few studies have reported the presence of histological changes in the GB following transduodenal drainage procedures in children with PBM. The aim of this study was to document the histological changes in the GB in children who underwent interval prophylactic cholecystectomy up to 18 years following PBM drainage procedure. All children who underwent open transduodenal sphincterotomy (TDS) for symptomatic PBM followed by prophylactic synchronous (open) and interval (laparoscopic) cholecystectomy between 1987 and 2007 were studied retrospectively. Eight children with PBM were identified. The median age at initial presentation and open transduodenal sphincterotomy was 8 months (1 month–3.5 years). The average interval between open TDS and prophylactic cholecystectomy was 5.5 years (0–18 years). Two children had synchronous TDS and cholecystectomy. At initial presentation, all patients presented with obstructive jaundice. Mild common bile duct dilatation was encountered in all patients. The dilated ducts returned to normal, and remained normal after transduodenal sphincterotomy. Histopathology in seven out of eight GB specimens (87.5%) showed microscopic evidence of chronic inflammation. Chronic cholecystitis (n = 7), Rokitansky–Aschoff sinuses (n = 3), cholesterosis (n = 1) and intestinal metaplasia (n = 1) were observed in the GB biopsies. Only one patient, who had TDS and a synchronous cholecystectomy in the neonatal period, did not have histological changes in the GB. Average follow-up in years ranged between 3 months and 19 years (from TDS) with a median of 8 years, and between 3 months and 6 years (from cholecystectomy) with a median of 2 years. Chronic inflammatory changes were found in seven of eight GB specimens from patients with PBM despite previous drainage procedure in six patients and in one of two patients who underwent synchronous TDS and cholecystectomy. These changes may be the precursor of malignant transformation in GB of patients with PBM.Abdelbasit E. Ali, Alex I. Blythe and William D. A. For

Sequential sampling designs for the two-parameter item response theory model

sequential sampling design, efficiency, item response theory models, two-parameter logistic model, optimality criteria,