Reliability & Confidence for Serially Connected Systems

In most test programs component test results are available. It is in general a fairly easy task to find lower one-side confidence limits on the probability of failure of a chosen component. Either variable data or attribute (success-failure) data can be used. From a statistical point of view it is most often more desirable to use variable data (like pressure, temperature or specific impulse, etc.). From that information, upper one-sided confidence limits on the reliability of the component can be secured. It is true, in general, that different components are tested under varied conditions with an unequal sample size. A long-standing problem of interest to both the engineer and statistician is: How can the component reliabilities at different or identical confidence levels be combined to find the system reliability at a chosen confidence level

Diamonds are Forever

We defend the thesis that every necessarily true proposition is always true. Since not every proposition that is always true is necessarily true, our thesis is at odds with theories of modality and time, such as those of Kit Fine and David Kaplan, which posit a fundamental symmetry between modal and tense operators. According to such theories, just as it is a contingent matter what is true at a given time, it is likewise a temporary matter what is true at a given possible world; so a proposition that is now true at all worlds, and thus necessarily true, may yet at some past or future time be false in the actual world, and thus not always true. We reconstruct and criticize several lines of argument in favor of this picture, and then argue against the picture on the grounds that it is inconsistent with certain sorts of contingency in the structure of time

Brief Note Surface Charge Determination of Proteus Mirabilis Exposed to Carbenicillin

Author Institution: Division of Infectious Diseases, Department of Medicine, The Ohio State University College of Medicin

Association between the preoperative fasting and postprandial C-peptide AUC with resolution of type 2 diabetes 6 months following bariatric surgery

Background and AimsBariatric surgery results in the remission of type 2 diabetes mellitus (T2DM) in morbidly obese subjects. The aim of the study was to investigate the predictive value of both static and dynamic measures of C-peptide in relation to T2DM resolution 6 months after bariatric surgery regardless of the operation type.Methods and ResultsA non-randomized prospective study of 24 participants with T2DM undergoing bariatric surgery. Measurements of fasting and 2-hour plasma glucose, insulin, C-peptide and measures of insulin sensitivity were recorded temporally during an oral glucose tolerance test pre-operatively and 6 months post-operatively. A responder was defined with a fasting glucose < 5.6mmol/L and HBA1c < 6.0% postoperatively. Within the sample there were 11 responders and 13 non-responders at 6 months. There was a significant difference in the duration of diabetes between the groups. Fasting C-peptide (P≤0.05) and 2-hour C-peptide (P≤0.05) were higher in responders compared to non-responders. Significantly higher C-peptide levels were observed preoperatively at all time points for responders, with significantly higher area under the curve (AUC0–60 and AUC0–120). Using the lower quartiles for C-peptide levels, both fasting C-peptide (> 2.5ng/mL [0.83nmol/L]) and 2-hour C-peptide (> 5.2ng/mL [1.73nmol/L]) had a sensitivity and negative predictive value of 100% to predict T2DM remission. Logistic regression showed C-peptide, duration of diabetes and BMI were associated with response. The area under the ROC curve was 0.94 and a regression model predicted diabetes remission with a sensitivity of 85.7% and a specificity of 88.9%.ConclusionsThis study demonstrated that static (fasting) and dynamic (AUC, 2-hour) C-peptide measurements predict T2DM resolution 6 months following bariatric surgery. This work provides insight into C-peptide dynamics as a predictor of response to bariatric surgery