Measuring change in subjective wellbeing: Methods to quantify recall bias and recalibration response shift

We propose to use subjective well-being (SWB) measures to determine patient-relevant treatment benefit. Benefit can be measured either prospectively (pre-post) or retrospectively, but both approaches can be biased: Prospective evaluation may be subject to response shift; retrospective evaluation may be subject to recall bias. As prospective and retrospective evaluations often differ in effect size and since there is no gold standard to compare against, the extent of the two biases needs to be determined. Response shift includes reprioritization, reconceptualization, and recalibration. We argue that in SWB measures only recalibration, but not reprioritization and reconceptualization are validity threats. We review approaches to quantify recall bias, response shift, or both in the measurement of health-related quality of life. We discuss which of these approaches are most suitable for application to SWB measurement, where only recall bias and recalibration are to be quantified, ignoring the other two response shift types. Some approaches of bias detection will not be applicable to SWB measurement, because they do not distinguish between recalibration and other types of response shift, or quantify reprioritization and/or reconceptualization alone. For other approaches, it is unclear whether underlying assumptions apply to SWB measurement. Anchor recalibration, structural equation modelling, and ROSALI are most suitable, the latter two with some limitations. Anchor recalibration was considered by its developers to be too difficult for participants to understand in its current form. Refining the anchor recalibration method may provide the most promising way to quantify both scale recalibration and recall bias

A robust Bayesian analysis of the impact of policy decisions on crop rotations.

We analyse the impact of a policy decision on crop rotations, using the imprecise land use model that was developed by the authors in earlier work. A specific challenge in crop rotation models is that farmer’s crop choices are driven by both policy changes and external non-stationary factors, such as rainfall, temperature and agricultural input and output prices. Such dynamics can be modelled by a non-stationary stochastic process, where crop transition probabilities are multinomial logistic functions of such external factors. We use a robust Bayesian approach to estimate the parameters of our model, and validate it by comparing the model response with a non-parametric estimate, as well as by cross validation. Finally, we use the resulting predictions to solve a hypothetical yet realistic policy problem

Using imprecise continuous time Markov chains for assessing the reliability of power networks with common cause failure and non-immediate repair.

We explore how imprecise continuous time Markov chains can improve traditional reliability models based on precise continuous time Markov chains. Specifically, we analyse the reliability of power networks under very weak statistical assumptions, explicitly accounting for non-stationary failure and repair rates and the limited accuracy by which common cause failure rates can be estimated. Bounds on typical quantities of interest are derived, namely the expected time spent in system failure state, as well as the expected number of transitions to that state. A worked numerical example demonstrates the theoretical techniques described. Interestingly, the number of iterations required for convergence is observed to be much lower than current theoretical bounds

What are the effects of climate change on agriculture in North East Central Europe?

Global and climate changes influence the basic conditions for agriculture and so there is not only a demand for a consequent climate protection but also for an adaptation of agriculture to these global changing conditions. For the whole "Maerkisch-Oderland" district (60x40 km) within the moraine landscape of North-East-Germany mainly used for agriculture water balance, nitrogen and sulphur loads as well as crop yields are calculated for two land use and climate scenarios. The comparison between the Scenario2050 and the Scenario2000 reveals significant changes of the water balance (decrease in percolation water, increase in actual evapotranspiration) as well as the concentration of the examined nitrogen in the percolation water. For the study region the crop yields decrease only slightly if the CO2 fertilizing effect is taken into account. Adaptation measures in reaction to the changing climate conditions for an economically secured and sustainable agriculture are recommended.climate change impact assessment, water balance, nitrogen load, crop yield, moraine landscape, Environmental Economics and Policy, Farm Management,

The electrocatalytic ORR activity of nanostructured manganese oxides in aprotic media

In this work nanostructured manganese oxides were synthesized and characterized with respect to their electrocatalytic activities for the oxygen reduction reaction (ORR) in aprotic media. The carbon substrate used for the electrochemical measurements shows an ORR pathway, which results in an electron transfer subsequent to a chemical reaction. The intermediate species Oads being generated during this process, is supposed to enhance the decomposition of aprotic electrolytes. Mn3O4 is catalytically active for this mechanism, whereas [alpha]-Mn2O3 catalyzes a direct electrochemical reduction of O2, which results in the formation of the desired final product Li2O2. Based on the obtained mechanistic insights conclusions on the morphological and structural properties of an ideal ORR electrocatalyst are drawn

Numerical Simulation of the Fouling on Structured Heat Transfer Surfaces (Fouling)

The objective of this work is to make a contribution to a good and fast prediction of the crystal growth on flat and structured heat transfer surfaces. For the numerical simulation the CFD code Fluent is used. The simulation enables an unsteady calculation of the fouling process and a realistic description of the temporal modification of the flow and temperature fields due to the continuous crystal growth. The numerical simulation of the crystal growth is based on models for the calculation of the deposition (Krause, 1993) and removal (Bohnet, 1990) mass rates. Based on experimental results of Hirsch (Bohnet et. al., 1999), a model was developed which enables the calculation of the density of the fouling layer not only as a function of the local position within the fouling layer, but also as a function of the time-dependent total thickness of the fouling layer. In addition a model was developed, that enables a realistic distribution of the heat flux along the heat transfer surface during the simulation. All models are implemented into the simulation with the help of the programming user interface of the CFD code. During the experimental and numerical investigations the operating parameters like flow rate, surface temperature, concentration of the salt solution and geometry of the flow channel are varied. The induction period and the effects of aging which occur with almost all fouling processes are not considered. Result of the numerical simulation is the prediction of the fouling resistance as function of time. In view of the complexity of the fouling process during the incrustation of heat transfer surfaces and the fact that not all influences from the used models could be considered the agreement between calculated and experimentally obtained data is satisfactory

Crystallization Fouling Of The Aqueous Two-Component System CaSO\u3csub\u3e4\u3c/sub\u3e/CaCO\u3csub\u3e3\u3c/sub\u3e

Solutions, which cause fouling problems, consist mostly of more than one single component. Up to now only few studies concerning the fouling phenomena in such multicomponent systems exist. Therefore batch and continuous experiments with the aqueous two-component system CaSO4/CaCO3 were carried out, investigating especially the influence of pH-value on the fouling behaviour. As measure for the crystalline deposit the fouling resistance Rf was used. The composition of the obtained fouling layers were analysed by x-ray diffraction and scanning electron microscopy (SEM). Further the strength of the crystalline deposits were determined in abrasion experiments. The measured abrasion was correlated with crushing strength values. In the fouling experiments a strong effect of the pH-value on crystallization fouling was observed. Lowest fouling tendency was seen for experiments at pH 7.0. At different pH-values the crystalline layers showed big differences in their macroscopic as well as in their microscopic structure. As it could be seen with the SEM the crystals differed in their size but also in their shape. Below pH 6.0 only calcium sulphate was detected by x-ray diffraction, which agrees with the saturation theory. At higher pH values besides calcium sulphate also calcium carbonate was found in different modifications. The different layer composition leads to different strength of the layers. Highest strength values in the crystalline upper and middle layer were measured for crystalline scales grown at pH 7.0, followed by layers at pH 6.5. At the moment it is difficult to correlate the fouling behaviour clearly to the different experimental conditions