The Future of Retirement and the Pension System: How the Public’s Expectations Vary over Time and across Socio-Economic Groups

We analyze expectations of the Dutch population of ages 25 and older concerning the future generosity state and occupational pensions, the two main pillars of the Dutch pension system. Since the summer of 2006, monthly survey data were collected on the expectations of Dutch households concerning purchasing power of occupational pensions, eligibility and purchasing power of old age social security benefits, and the average retirement age ten or twenty years from now. We investigate how these expectations have changed over time and how they vary with socio-economic characteristics. Exploiting the fact that we have data until September 2010, we also analyze the effect of the recent financial and economic crisis. We find significant differences in expectations of different socio-economic groups, mainly suggesting that groups who are probably better informed were also more pessimistic.subjective probabilities;old age social security;occupational pensions

Price dynamics and trading volume: A semiparametric approach

In this paper we investigate the relation between price impact and trading volume for a sample of stocks listed on the New York Stock Exchange. The parametric VAR-models that have been used in the literature impose strong proportionality and symmetry restrictions on the price impact of trades, although market microstructure theory provides many reasons why these restrictions would not hold. We analyze a more flexible semiparametric partially linear specification and establish significant evidence for a nonlinear, asymmetric, increasing, and concave relation between trading volume and both immediate and persistent price impact. Moreover, we compare the price-impact functions obtained in the partially linear model to the ones generated by the parametric models and show that there are considerable differences. We test the parametric specifications against the partially linear model and show that the parametric models are rejected in favor of the semiparametric model. We also test the partially linear model against a more flexible fully nonparametric specification and show that this test does not reject the partially linear model

The Price Impact of Trades in Illiquid Stocks in Periods of High and Low Market Activity

Using high frequency data on ten infrequently traded stocks during the year 1999, we measure the information content of a trade and its relation to the trading intensity.While the price impact curve for frequently traded stocks monotonically increases towards the full information price, we find impulse response functions that first 'over-shoot' and subsequently decrease towards the full information price.The overshooting effect strongly depends upon the bid-ask spread and the trading intensity, which can be explained by inventory imbalances and asymmetric information of informed and uninformed traders.Furthermore, we show that the difference in price impact between periods of slow and fast trading is much larger for illiquid stocks than for frequently traded stocks.We model the overnight behavior of the trading intensity and returns and show that information contained in the trading intensity of illiquid stocks is carried over to the next day.Additionally, we show that, for infrequently traded stocks, it may take several days before the full information price that follows a trade is attained, even in periods of relatively high market activity.Moreover, the adjustment time crucially depends upon the bid-ask spread and the trading intensity.prices;trade;duration analysis;asymmetric information

Validating the Use of Vignettes for Subjective Threshold Scales

Comparing self-assessed indicators of subjective outcomes such as health, work disability, political efficacy, job satisfaction, etc. across countries or socio-economic groups is often hampered by the fact that different groups use systematically different response scales. Anchoring vignettes have been introduced as an effective tool to correct for such differences. This paper develops an integrated framework in which objective measurements are used to validate the vignette-based corrections. The framework is applied to vignettes and objective and subjective self-assessments of drinking behavior by students in Ireland. Model comparisons using the Akaike information criterion favor a specification with response consistency and vignette corrected response scales. Put differently, vignette based corrections appear quite effective in bringing objective and subjective measures closer together.anchoring vignettes;reporting bias;hopit model

Modeling Comovements in Trading Intensities to Distinguish Sector and Stock Specific News

In this paper we propose a bivariate model for the trading intensities of stocks in a particular industry.The model consists of a univariate duration model for trades in either of the stocks and a probit-specification for which of the two stocks is traded.We apply the model to the trading intensities of stocks of US department store operators listed on the NYSE, using high frequency transaction data during the period August 1 until October 31, 1999.We establish significant comovements in the trading intensities of US department stocks, which we explain by distinguishing sector and stock specific news contained in the trading intensities.We provide estimates of the amounts of sector and stock specific news contained in the trading intensities and show that all stocks under consideration convey both sector and stock specific news.

Large-scale validation of SCIAMACHY reflectance in the ultraviolet

In this paper we present an extensive validation of calibrated SCIAMACHY nadir reflectance in the UV (240-400 nm) by comparison with spectra calculated with a fast radiative transfer model. We use operationally delivered near-real-time level 1 data, processed with standard calibration tools. A total of 9 months of data has been analysed. This is the first reflectance validation study incorporating such a large amount of data. It is shown that this method is a valuable tool for spotting spatial and temporal anomalies. We conclude that SCIAMACHY reflectance data in this wavelength range are stable over the investigated period. In addition, we show an example of an anomaly in the data due to an error in the processing chain that could be detected by our comparison. This validation method could be extremely useful too for validation of other satellite spectrometers, such as OMI and GOME-2

Aqueous extraction of residual oil from sunflower press cake using a twin-screw extruder: Feasibility study

The objective of this study was to evaluate the feasibility of an aqueous process to extract the residual oil from sunflower press cakes using a co-rotating twin-screw extruder. Two different configurations were tested: the expression from whole seeds followed by the aqueous extraction, in two successive apparatus or in the same one. For the aqueous extraction stage, the oil yield depended on the operating conditions including screw rotation speed, screw profile, and inlet flow rates of press cakes and water. Liquid/solid separation required the addition of a lignocellulosic residue (wheat straw), upstream from the filtration zone. However, even with maximum fiber inlet flow (around 20% of the inlet flow rate of the solid matters for the highest amount of wheat straw), drying of the cake meal did not improve. The lixiviation of the material was also incomplete. Oil yield was better when the expression and the aqueous extraction were conducted in the same extruder. For all the trials carried out using such a configuration, the corresponding cake meal contained less than 10% residual oil, and the total oil yield was 78% in the best operating conditions. Nevertheless, the contribution of the aqueous extraction stage was extremely limited, less than 5% in the best trial, partly due to a ratio of the water to the press cake too low. For the aqueous extraction stage, the oil was extracted in the form of an oil-in-water emulsion whose stability was minimized because of its low proteins content due to their thermomechanical denaturation during the expression stage

Direct extraction of oil from sunflower seeds by twin-screw extruder according to an aqueous extraction process: Feasibility study and influence of operating conditions

The objective of this study was to evaluate the feasibility of an aqueous process to extract sunflower seed oil using a co-rotating twin-screw extruder. Aqueous extraction was carried out using whole seeds and the influence of the operating conditions on oil yield was examined. Operating conditions included screw profile, screw rotation speed, and input flow rates of sunflower seeds and water. Liquid/solid separation required the addition of a lignocellulosic residue upstream from the filtration zone. However, even with maximum fiber input flow, drying of the cake meal did not improve. The lixiviation of the sunflower seeds was also incomplete. The aqueous extraction of the oil was more efficient in the twin-screw extruder than the reference trial conducted in a batch reactor. The best oil extraction yield obtained was approximately 55% and the residual oil content of the cake meal was approximately 30%. The hydrophobic phases produced were oil-in-water emulsions. These emulsions were stabilized by phospholipids and proteins at the interface, which are natural surface-active agents co-extracted during the process

Huxley-type cross-bridge models in largeish-scale musculoskeletal models; an evaluation of computational cost

A Huxley-type cross-bridge model is attractive because it is inspired by our current understanding of the processes underlying muscle contraction, and because it provides a unified description of muscle's mechanical behavior and metabolic energy expenditure. In this study, we determined the computational cost for task optimization of a largeish-scale musculoskeletal model in which muscles are represented by a 2-state Huxley-type cross-bridge model. Parameter values defining the rate functions of the Huxley-type cross-bridge model could be chosen such that the steady-state force-velocity relation resembled that of a Hill-type model. Using these parameter values, maximum-height squat jumping was used as the example task to evaluate the computational cost of task optimization for a skeletal model driven by a Huxley-type cross-bridge model. The optimal solutions for the Huxley- and Hill-type muscle models were similar for all mechanical variables considered. Computational cost of the Huxley-type cross-bridge model was much higher than that of the Hill-type model. Compared to the Hill-type model, the number of state variables per muscle was large (2 vs about 18,000), the integration step size had to be about 100 times smaller, and the computational cost per integration step was about 100 times higher

Optimizing the Distribution of Leg Muscles for Vertical Jumping.

A goal of biomechanics and motor control is to understand the design of the human musculoskeletal system. Here we investigated human functional morphology by making predictions about the muscle volume distribution that is optimal for a specific motor task. We examined a well-studied and relatively simple human movement, vertical jumping. We investigated how high a human could jump if muscle volume were optimized for jumping, and determined how the optimal parameters improve performance. We used a four-link inverted pendulum model of human vertical jumping actuated by Hill-type muscles, that well-approximates skilled human performance. We optimized muscle volume by allowing the cross-sectional area and muscle fiber optimum length to be changed for each muscle, while maintaining constant total muscle volume. We observed, perhaps surprisingly, that the reference model, based on human anthropometric data, is relatively good for vertical jumping; it achieves 90% of the jump height predicted by a model with muscles designed specifically for jumping. Alteration of cross-sectional areas-which determine the maximum force deliverable by the muscles-constitutes the majority of improvement to jump height. The optimal distribution results in large vastus, gastrocnemius and hamstrings muscles that deliver more work, while producing a kinematic pattern essentially identical to the reference model. Work output is increased by removing muscle from rectus femoris, which cannot do work on the skeleton given its moment arm at the hip and the joint excursions during push-off. The gluteus composes a disproportionate amount of muscle volume and jump height is improved by moving it to other muscles. This approach represents a way to test hypotheses about optimal human functional morphology. Future studies may extend this approach to address other morphological questions in ethological tasks such as locomotion, and feature other sets of parameters such as properties of the skeletal segments