Australian coal mining: Estimating technical change and resource rents in a translog cost function

This paper estimates a translog cost function for the Australian coal industry from 1968/69 to 2004/05. We use a variable measuring the shift to open-pit mining to capture the impact of embodied technical change, while using a time trend to capture the impact of other technical change and changing resource rents. The cost function is estimated with Zellner's SUR procedure. The shift to open-cut mining is shown to be important in lowering cost during the 1970s and 1980s, but more recently cost reduction is captured by the time trend

In-Stent CTO Percutaneous Coronary Intervention: Individual Patient Data Pooled Analysis of 4 Multicenter Registries

OBJECTIVES: The authors sought to examine the outcomes of percutaneous coronary intervention (PCI) for in-stent restenosis (ISR) chronic total occlusions (CTOs). BACKGROUND: The outcomes of PCI for ISR CTOs have received limited study. METHODS: The authors examined the clinical and angiographic characteristics and procedural outcomes of 11,961 CTO PCIs performed in 11,728 patients at 107 centers in Europe, North America, Latin America, and Asia between 2012 and 2020, pooling patient-level data from 4 multicenter registries. In-hospital major adverse cardiovascular events (MACE) included death, myocardial infarction, stroke, and tamponade. Long-term MACE were defined as the composite of all-cause death, myocardial infarction, and target vessel revascularization. RESULTS: ISR represented 15% of the CTOs (n = 1,755). Patients with ISR CTOs had higher prevalence of diabetes (44% vs. 38%; p \u3c 0.0001) and prior coronary artery bypass graft surgery (27% vs. 24%; p = 0.03). Mean J-CTO (Multicenter CTO Registry in Japan) score was 2.32 ± 1.27 in the ISR group and 2.22 ± 1.27 in the de novo group (p = 0.01). Technical (85% vs. 85%; p = 0.75) and procedural (84% vs. 84%; p = 0.82) success was similar for ISR and de novo CTOs, as was the incidence of in-hospital MACE (1.7% vs. 2.2%; p = 0.25). Antegrade wiring was the most common successful strategy, in 70% of ISR and 60% of de novo CTOs, followed by retrograde crossing (16% vs. 23%) and antegrade dissection and re-entry (15% vs. 16%; p \u3c 0.0001). At 12 months, patients with ISR CTOs had a higher incidence of MACE (hazard ratio: 1.31; 95% confidence intervals: 1.01 to 1.70; p = 0.04). CONCLUSIONS: ISR CTOs represent 15% of all CTO PCIs and can be recanalized with similar success and in-hospital MACE as de novo CTOs

Impact of point-of-care pre-procedure creatinine and eGFR testing in patients with ST segment elevation myocardial infarction undergoing primary PCI: The pilot STATCREAT study

Background: Contrast-induced acute kidney injury (CI-AKI) is a recognised complication during primary PCI that affects short and long term prognosis. The aim of this study was to assess the impact of point-of-care (POC) pre-PPCI creatinine and eGFR testing in STEMI patients. Methods 160 STEMI patients (STATCREAT group) with pre-procedure POC testing of Cr and eGFR were compared with 294 consecutive retrospective STEMI patients (control group). Patients were further divided into subjects with or without pre-existing CKD. Results: The incidence of CI-AKI in the whole population was 14.5% and not different between the two overall groups. For patients with pre-procedure CKD, contrast dose was significantly reduced in the STATCREAT group (124.6 ml vs. 152.3 ml, p = 0.015). The incidence of CI-AKI was 5.9% (n = 2) in the STATCREAT group compared with 17.9% (n = 10) in the control group (p = 0.12). There was no difference in the number of lesions treated (1.118 vs. 1.196, p = 0.643) or stents used (1.176 vs. 1.250, p = 0.78). For non-CKD patients, there was no significant difference in contrast dose (172.4 ml vs. 158.4 ml, p = 0.067), CI-AKI incidence (16.7% vs. 13.4%, p = 0.4), treated lesions (1.167 vs. 1.164, p = 1.0) or stents used (1.214 vs. 1.168, p = 0.611) between the two groups. Conclusions: Pre-PPCI point-of-care renal function testing did not reduce the incidence of CI-AKI in the overall group of STEMI patients. In patients with CKD, contrast dose was significantly reduced, but a numerical reduction in CI-AKI was not found to be statistically significant. No significant differences were found in the non-CKD group

Australian Coal Mining: Estimating technical change and resource exhaustion in a translog cost function

This paper estimates a translog cost function for the Australian coal industry from 1968 to 2001. We use a variable measuring the shift to open-pit mining to capture the impact of technical change, while using a time trend to capture the impact of resource exhaustion. The cost function is estimated with the Zellner's SUR procedure. Technical change is significant in lowering cost, but over time this cost reduction has been largely offset by the impact of resource exhaustion

Testing for a deficit in single-case studies: Effects of departures from normality

In neuropsychological single-case research inferences concerning a patient's cognitive status are often based on referring the patient's test score to those obtained from a modestly sized control sample. Two methods of testing for a deficit (z and a method proposed by Crawford and Howell [Crawford, J. R. & Howell, D. C. (1998). Comparing an individual's test score against norms derived from small samples. The Clinical Neuropsychologist, 12, 482-486]) both assume the control distribution is normal but this assumption will often be violated in practice. Monte Carlo simulation was employed to study the effects of leptokurtosis and the combination of skew and leptokurtosis on the Type I error rates for these two methods. For Crawford and Howell's method, leptokurtosis produced only a modest inflation of the Type I error rate when the control sample N was small-to-modest in size and error rates were lower than the specified rates at larger N. In contrast, the combination of leptokurtosis and skew produced marked inflation of error rates for small Ns. With a specified error rate of 5%, actual error rates as high as 14.31% and 9.96% were observed for z and Crawford and Howell's method respectively. Potential solutions to the problem of non-normal data are evaluated. (c) 2005 Elsevier Ltd. All rights reserved

The quantile-based skew logistic distribution

We show that the quantile-based skew logistic distribution possesses kurtosis measures based on L-moments and on quantiles which are skewness invariant. We furthermore derive closed-form expressions for method of L-moments estimators for the distribution’s parameters together with asymptotic standard errors for these estimators.Vice-Chancellor’s Academic Development Grant at the University of Pretoria and the University of Newcastle Special Studies Program.http://www.elsevier.com/locate/staprohj201