Model Selection,Transformations and Variance Estimation in Nonlinear Regression

The results of analyzing experimental data using a parametric model may heavily depend on the chosen model for regression and variance functions, moreover also on a possibly underlying preliminary transformation of the variables. In this paper we propose and discuss a complex procedure which consists in a simultaneous selection of parametric regression and variance models from a relatively rich model class and of Box-Cox variable transformations by minimization of a cross-validation criterion. For this it is essential to introduce modifications of the standard cross-validation criterion adapted to each of the following objectives: 1. estimation of the unknown regression function, 2. prediction of future values of the response variable, 3. calibration or 4. estimation of some parameter with a certain meaning in the corresponding field of application. Our idea of a criterion oriented combination of procedures (which usually if applied, then in an independent or sequential way) is expected to lead to more accurate results. We show how the accuracy of the parameter estimators can be assessed by a “moment oriented bootstrap procedure", which is an essential modification of the “wild bootstrap” of Härdle and Mammen by use of more accurate variance estimates. This new procedure and its refinement by a bootstrap based pivot (“double bootstrap”) is also used for the construction of confidence, prediction and calibration intervals. Programs written in Splus which realize our strategy for nonlinear regression modelling and parameter estimation are described as well. The performance of the selected model is discussed, and the behaviour of the procedures is illustrated, e.g., by an application in radioimmunological assay.     

Nature and the international: towards a materialist understanding of societal multiplicity

ABSTRACT

The global environmental crisis requires a grasp of how human society interacts with nature, but also, simultaneously, how the world is divided into multiple societies. International Relations has a weak grasp of nature treating it as external to the international – an ‘environment’ to be managed – while environmentalism has a planetary epistemology that occludes the significance of the international. How to break this impasse? While neither Geopolitics nor ‘new materialism’ capture the complex conjuncture of socio-natural and inter-societal dynamics, I argue that Justin Rosenberg’s theorization of the international as ‘the consequences of societal multiplicity’ provides a theoretical opening. If a materialist notion of societal is adopted, ‘societal multiplicity’ allows human-natural and international dynamics to be grasped together. Thus, climate change is not a problem arising exogenously to the international, but something emerging through international dynamics, reciprocally affecting the units, structure and processes of the international system itself.     

Poverty among households with children: a comparative study of Norway and Germany

The purpose of this study was to compare poverty among lone parent households and couple households with children in Norway and Germany. The study applied three different measurement strategies: income poverty, material deprivation and reception of social assistance. We found that income poverty and material deprivation rates are higher in Germany than in Norway and are also higher for lone parents than for couples with children. Our analysis of the reception of social assistance shows a different pattern in which both Norwegian and German lone parents frequently receive social assistance. The results show that the different dimensions of poverty are not independent of one another, nor do they wholly overlap. Household characteristic variables, factors influencing labour market status and educational levels also seem to influence the risk of experiencing poverty.     

Religiös-konfessionelle Kultur und individuelle Religiosität: Ein Vergleich zwischen West- und Ostdeutschland

In religious terms, East and West Germany are still two separate societies more than 20 years after reunification. While the large majority of the population in West Germany belongs to one of the two main Christian churches, the proportion of those without a denomination in East Germany is now more than 70 %. Moreover, as far as church involvement, confidence in the church and individual religiosity are concerned, the West Germans have a much stronger religious affiliation to the church than their East German counterparts. The main reason for this difference is the influence of different political systems and legal cultures in East and West during the period when the two parts of Germany were divided. The fact, though, that the process of secularization has continued unabated in East Germany since 1989, and that the religious and ecclesiastical discrepancies between the two parts of the country have, if anything, become stronger rather than weaker since then, would suggest that there are other factors at work here, too. In this contribution, we argue that one of the factors that needs to be considered is the dominant denominational culture that exists in each of the two parts of the country, a culture which is highly persistent, can easily reproduce itself, puts pressure on the respective minority cultures, and is able to diffuse into them. While the dominant denominational culture in West Germany is able to slow down the current processes of secularization, the secular, non-denominational majority culture in the East tends rather to produce effects which accelerate these processes. In this essay, we use a variety of empirical indicators (effectiveness of religious socialization, denominational affiliation, churchly affiliation, faith in God) to demonstrate these effects.     

Capacity for Stakeholder Participation in Recovery Planning

It is generally accepted that meaningful participation by a representative, well-informed public contributes to a better plan. We surveyed the lead official responsible for the development of recovery plans in a sample of US Atlantic and Gulf Coast counties to determine capacity for stakeholder participation. We report on a variety of engagement techniques that were positively associated with an increase in participation in recovery plan development. We also link increased participation with better plan quality scores in plan quality principles. Investing human and fiscal resources in participation can increase involvement in the planning process and improve recovery plan quality.     

Aircraft seating comfort: the influence of seat pitch on passengers' well-being

One of the most important factors influencing aircraft seating comfort in economy class, is legroom. In an airline interior mock up, with the ability to adjust the seat pitch in a range of 28 inches to 43 inches, a study to investigate the influence of seat pitch on passengers' well-being was conducted. In a pre-study, aspects of subjective postural sensations and spatial perception were identified, and a questionnaire was developed. In the main study, 30 subjects rated at different seat pitch settings the spatial perception and the ability of adopting and changing sitting postures. As a result a functional relationship between overall well-being, the subjects' anthropometry and seat pitch was developed. Furthermore it was identified, that there is a maximum overall well-being at a seat pitch of 34 inches to 40 inches, depending on the passengers' anthropometry. A further enlargement of seat pitch, led to a reduction of well-being.