Orbifold Index Cobordism Invariance

We prove cobordism index invariance for pseudo-differential elliptic operators on closed orbifolds with $K$--theoretical methods.Comment: New proofs for Theorems 4.2 and 4.3, results extended to all actions by compact Lie group

Risk-Aversion and Willingness to Pay for Energy Efficient Systems in Rental Apartments

This paper uses a random utility model with a non-linear utility function to estimate the consumers’ valuation for energy efficient insulation and ventilation systems in apartment buildings. The proposed model is applied to data from a choice experiment conducted among 264 apartment tenants in Switzerland. The model relaxes the assumption of constant rate of substitution between income and energy-saving measures. These amenities are considered as non-market goods whose advantages are little known thus entailing certain risk-aversion in consumers’ preferences. The non-linear formulation can accommodate the common cases when the non-market attributes are measured by discrete variables. The analysis indicates that assuming constant rate of substitution could bring about misleading estimates of the willingness to pay, especially when the system is combined of several components. The findings provide evidence in favor of consumers’ risk-averse behavior facing choice situations regarding energy-efficient systems. The estimated risk premiums suggest that risk considerations remain a central issue in dealing with energy efficiency in residential buildings.choice experiment; willingness to pay; risk aversion; energy efficiency; housing

Cellular buckling in stiffened plates

An analytical model based on variational principles for a thin-walled stiffened plate subjected to axial compression is presented. A system of nonlinear differential and integral equations is derived and solved using numerical continuation. The results show that the system is susceptible to highly unstable local--global mode interaction after an initial instability is triggered. Moreover, snap-backs in the response showing sequential destabilization and restabilization, known as cellular buckling or snaking, arise. The analytical model is compared to static finite element models for joint conditions between the stiffener and the main plate that have significant rotational restraint. However, it is known from previous studies that the behaviour, where the same joint is insignificantly restrained rotationally, is captured better by an analytical approach than by standard finite element methods; the latter being unable to capture cellular buckling behaviour even though the phenomenon is clearly observed in laboratory experiments.Comment: 22 pages, 9 figures, 1 table, accepted for publication. Proceedings of the Royal Society A, 201

Effects of ownership, subsidization and teaching activities on hospital costs in Switzerland

This paper explores the cost structure of Swiss hospitals, focusing on differences due to teaching activities and those across different ownership and subsidization types. A stochastic total cost frontier with a Cobb-Douglas functional form has been estimated for a panel of 150 general hospitals over the six-year period from 1998 and 2003. Inpatient cases adjusted by DRG cost weights and ambulatory revenues are considered as two separate outputs. The adopted econometric specification allows for unobserved heterogeneity across hospitals. The results indicate that the time-invariant unobserved factors could account for considerable cost differences that could be only partly due to inefficiency. The results suggest that teaching activities are an important cost driving factor and hospitals that have a broader range of specialization are relatively more costly. The excess costs of university hospitals can be explained by more extensive teaching activities as well as the relatively high quality of medical units. However, even after controlling for such differences university hospitals have shown a relatively low cost-efficiency especially in the first two or three years of the sample period. The analysis does not provide any evidence of significant efficiency differences across ownership and subsidization categories.general hospitals, teaching hospitals, stochastic frontier, cost efficiency

Effect of Urtica dioica L extract on quantitative morphometric alterations of liver parenchymal cells in STZ diabetic rats

Diabetes is associated with several structural and functional liver abnormalities that affect glycogen and lipid metabolism. In this study, an attempt was made to evaluate the effects of hydroalcoholic extract of Urtica dioica leaves on Quantitative morphometric changes in parenchymal cells of the livers in STZ diabetic rats. Thirty male Wistar rats were allocated in 3 groups: normal, diabetic and treatment. Hyperglycemia was induced by 80 mg/kg Streptozotocin intraperitoneally. One week after the injection of STZ, the third group received the hydroalcoholic extract of Urtica dioica at 100 mg/kg/day over four weeks. After five weeks, the animals were sacrificed and whole livers were removed. Liver specimens were used for quantitative morphometric analyze after hematoxylin and eosin staining. All data are shown as means plus standard errors of means and were analyzed using One-Way ANOVA test at P<0.05.The mean area of hepatocytes, nuclei and nucleolus had a decrease in periportal zone and an increase in perivenous zone in the diabetic and treatment groups. The increase of hepatocyte area in perivenous zone and reduce of nucleus area in periportal zone was significant in the diabetic group in comparison with control group (P<0.05), but were not significant between treatment and diabetic group. This study showed that administration of 100 mg/kg/day of Urtica dioica leaves extracts after induction of diabetes can cause a little modulating in the main morphometric indices of liver such as area of hepatocytes, nuclei and nucleolus in periportal and perivenous zones

A Benchmarking Analysis of Electricity Distribution Utilities in Switzerland

This paper studies the sensitivity problems of the benchmarking methods used in the regulation practice. Three commonly used methods have been applied to a sample of 52 electricity distribution utilities to estimate their cost efficiency. These methods include stochastic frontier, corrected ordinary least squares and data envelopment analysis. The results indicate that both efficiency scores and ranks are significantly different across various models. Especially considerable differences exist between parametric and non-parametric methods.

Regulation and Measuring Cost Efficiency with Panel Data Models: Application to Electricity Distribution Utilities

This paper examines the application of different parametric methods to measure cost efficiency of electricity distribution utilities. The cost frontier model is estimated using four methods: Displaced Ordinary Least Squares, Fixed Effects, Random Effects and Maximum Likelihood Estimation. These methods are applied to a sample of 59 distribution utilities in Switzerland. The data consist of an unbalanced panel over a nine-year period from 1988 to 1996. Different specifications are compared with regards to the estimation of cost frontier characteristics and inefficiency scores. The results point to some advantages for the FE model in the estimation of cost function’s characteristics. The mutual consistency of different methods with regard to efficiency measures is analyzed. The results are mixed. The summary statistics of inefficiency estimates are not sensitive to the specification. However, the ranking changes significantly from one model to another. In particular, the least and most efficient companies are not identical across different methods. These results suggest that a valid benchmarking analysis should be applied with special care. It is recommended that the regulator use several specifications and perform a (mutual) consistency analysis. Finally, the out-of-sample prediction errors of different models are analyzed. The results suggest that benchmarking methods can be used as a control instrument in order to narrow the information gap between the regulator and regulated companies.