X-efficiency and economies of scale in pension fund administration and investment

Pension funds’ operating costs impair pension benefits, so it is crucial for pension funds to operate at the lowest cost possible. In practice, we observe substantial differences in costs per member for Dutch pension funds, both across and within pension fund size classes. This article presents new estimates of scale economies of pension funds and is the first that also measures pension fund X-inefficiency. We use a unique supervisory data set which distinguishes between administrative and investment costs and apply various approaches and models. Our estimates show large economies of scale for pension fund administrations, but modest diseconomies of scale for investment activities. We also found that many pension funds have substantial X-inefficiencies for both administrative and investment activities. The two kinds of inefficiency differ across types of pension funds. Therefore, most pension funds should be able to improve their cost performance, and hence increase pension benefits

Improving the reliability of aluminothermic rail welds under high axle load conditions

Aluminothermic rail welding is widely used as an in track welding process due to its low cost, fast installation and equipment portability. Despite operational preferences, aluminothermic welding suffers from variations of the produced weld quality and defects which are the result of its cast-like process. As a consequence the probability of aluminothermic service failures may be higher than the parent rail, particularly under high axle load conditions. This paper addresses the risk of weld failure though the development of an analytical approach to assessing the fatigue behaviour of aluminothermic welds, and the development and implementation of an enhanced welder training and competency program which has contributed to a significant decrease in defective welds. The bending behavior of aluminothermic weld is investigated around two most important failure modes for heavy haul operation: horizontal split web (HSW) and straight break. Due to the cyclic nature of the applied loads, these failure modes are overseen in the context of fatigue crack analysis which involves fatigue crack initiation and propagation assessments. However, it is believed that the material distress as a result of wheel-rail contact stress, bending, weld residual and seasonal thermal stresses as well as weld geometry would highly affect the failure initiation sites and the life to crack initiation of the weld. In order to investigate the weld material distress, a thermo-structural finite element model of the rail weld has been developed incorporating the track stiffness behavior to enable us superpose the seasonal thermal effects with local bending and contact stresses. The effect of some heavy haul parameters such as contact patch lateral movement due to curving or hunting with various traction coefficients are also investigated. The simulation results show a good consistency between the bending behavior of the weld and fatigue crack initiation probability based on observations. The current study forms the basis for a comprehensive fatigue crack initiation analysis as the next stage of the project

Low tryptophan diet increases stress-sensitivity, but does not affect habituation in rats

Cerebral dysfunction of 5-HT (serotonin) has been associated with stress response and with affective disorders. Stress alone is insufficient to induce depression, since only a minor proportion of subjects that have experienced stressful life events develop depressive episodes. We investigated whether long-term brain 5-HT depletion induced in rats by a diet with low content of its precursor tryptophan affects stress-responsiveness in rats. Stress-sensitivity was measured through various physiological parameters and by measuring the rats' response to acoustic stimuli. One group of rats was subjected to daily acoustic stimulus sessions for 5 days. Other groups received both immobilization stress and acoustic stimulus sessions daily for either 9 days (chronic experiment) or 1 day (acute experiment). A low tryptophan diet led to decreases in plasma tryptophan levels, low ratio of tryptophan/large neutral amino acid, whole blood 5-HT, and neuronal 5-HT content in the Dorsal and Median Raphe Nuclei, as well as altered c-fos expression in the brain. Without concomitant immobilization, the diet alone did not affect reactivity and habituation to acoustic stimuli, although plasma corticosterone levels, but not the adrenal weights, were increased on day 5. Low tryptophan and chronic immobilization stress together with the acoustic testing procedure increased adrenal weight, plasma corticosterone levels and reactivity to the acoustic stimuli, but not the rate of habituation to acoustic stimuli. These results show that cerebral dysfunction of serotonin achieved through a low tryptophan diet, increases the sensitivity of rats to external and stressful stimuli, but does not impair the capacity to adapt to these stimuli. Accordingly, brain-serotonin modulates reactivity to stress, but not stress coping. (C) 2007 Elsevier Ltd. All rights reserved