In this paper, dynamic aspects of railway infrastructure operation and maintenance costs in Sweden are explored. Econometric cost functions are estimated to check the robustness of previous marginal cost estimates by introducing lags and leads of both dependent and independent variables. We find support for a forward-looking behaviour within the Swedish National Rail Administration (Banverket) ...

Suppose we have data from a bivariate model with parametric marginals. Efficient estimators of the parameters in the marginal models are generally not efficient in the bivariate model. In this article, we propose a method of improving these marginal estimators and demonstrate that the magnitude of this improvement can be as large as 100 percent in some cases.

background. this study evaluated the effect of two prophylaxis techniques on the marginal gap of ci v resin-modified glass-ionomer restorations. methods. standard cl v cavities were prepared on the buccal surfaces of 48 sound bovine mandibular incisors in this in vitro study. after restoration of the cavities with gc fuji ii lc resin-modified glass-ionomer, the samples were randomly assigned to...

Approximately 100,000 youths are currently incarcerated in the US, yet little is known whether such a penalty deters future crime or interrupts human capital formation in a way that increases the likelihood of later criminal behavior. This paper uses the incarceration tendency of randomly-assigned judges as an instrumental variable to estimate causal effects of juvenile incarceration on adult r...

To improve the assessment of plaque present on teeth, a new index, based on the original Modified Navy Plaque Index, has been developed. The primary modifications to the original Modified Navy Plaque Index were: (1) extending areas F (distal) and D (mesial) into the region just below the interproximal contact point, and (2) extending areas C and A so as to increase the gumline (or marginal ging...

The Marginal Value Theorem (MVT) is a cornerstone of biological theory. It connects the quality and distribution of patches in a fragmented habitat to the optimal time an individual should spend exploiting them, and thus its optimal rate of movement. However, predictions regarding how habitat alterations should impact optimal strategies have remained elusive, with heavy reliance on graphical ar...

Approaches to soil management, including problems of soil degradation and low soil fertility, have recently undergone major changes. The former view was to concentrate on achieving high levels of production from the more fertile areas, leaving the marginal lands for extensive use only. Steeply sloping and highly drought-prone areas were preferably not to be cultivated at all. Soil constraints w...

Anterior edentulous areas usually display unusual soft tissue configurations and compromised bone support in patients with marginal mandibulectomy. There are several treatment modalities for these patients. A removable partial denture may be the treatment of choice. Maximum stability of the partial denture base for mandibulectomy patients may be accomplished by the application of the neutral zo...