Influence of manganese and ammonium oxidation on the removal of 17 alpha-ethinylestradiol (EE2)

Flow-through reactors with manganese oxides were examined for their capacity to remove 17α-ethinylestradiol (EE2) at μg L⁻¹ and ng L⁻¹ range from synthetic wastewater treatment plant (WWTP) effluent. The mineral MnO₂ reactors removed 93% at a volumetric loading rate (B_V) of 5 μg EE2 L⁻¹ d⁻¹ and from a B_V of 40 μg EE2 L⁻¹ d⁻¹ on, these reactors showed 75% EE2 removal. With the biologically produced manganese oxides, only 57% EE2 was removed at 40 μg EE2 L⁻¹ d⁻¹. EE2 removal in the ng L⁻¹ range was 84%. The ammonium present in the influent (10 mg N L⁻¹) was nitrified and ammonia-oxidizing bacteria (AOB) were found to be of prime importance for the degradation of EE2. Remarkably, EE2 removal by AOB continued for a period of 4 months after depleting NH₄⁺ in the influent. EE2 removal by manganese-oxidizing bacteria was inhibited by NH₄⁺. These results indicate that the metabolic properties of nitrifiers can be employed to polish water containing EE2 based estrogenic activity.     

The housing careers of younger adults and intergenerational support in Germany’s ‘society of renters’

Abstract

Through narrative interviews with younger adults and their parents, this paper explores how the housing transitions of younger adults, both within the rental sector and into homeownership, are shaped through intergenerational intra-family support in Germany’s society of renters. Our findings highlight the profound qualitative differences between regular transfers for establishing and retaining residential independence in the rental sector and inter vivos gifts for house purchase. Where the former support type is given and taken unconditionally, transfers for house purchase follow a different logic and carry different meanings. Being a necessary condition for property acquisition at young age, they have the power to completely rebalance family relations and undermine younger adults’ autonomy accordingly. In an aggregate perspective, our study further suggests increasing socio-spatial inequalities within the younger generation which run along both class and spatial origin, sharply dividing the housing market opportunities of ‘original Berliners’ and those who have moved to the city from more affluent regions in Germany.     

SENSITIVITY ANALYSIS OF A ONE-DIMENSIONAL CONVECTION-DIFFUSION MODEL FOR SECONDARY SETTLING TANKS

One-dimensional models describing the flow and settling process in secondary settling tanks have great potential with respect to process control. Most of these models are based on a conservation equation that is discretized by dividing the settler into a fixed number of horizontal layers. In this article, the focus is on convection-diffusion models, which—in contrast to other one-dimensional models—ensure mesh-independent concentration profiles. The sensitivity of a prototype convection-diffusion model with respect to its parameters and the loading and operational conditions is studied by means of steady-state simulations. Based on the results, the importance of each of the model parameters is assessed. For each combination of parameter values, loading conditions, and operational variables considered in the study, the minimum number of layers required to obtain a practically mesh-independent concentration profile is determined on the basis of a newly developed objective criterion. This analysis leads to the identification of those factors having a large influence on the numerical behavior of the model.     

Pan-European Optical Transport Networks: An Availability-based Comparison

The traffic to be carried by today's European backbone networks increases very rapidly. An important portion of this traffic consists of data traffic (mainly IP-related). In the future data traffic is expected to become the abundantly dominant traffic type, while voice traffic will only account for a very small portion of the total traffic volume. In this paper, some network topologies for such a pan-European fiber-optic backbone network are presented (more details can be found in [1]). These topologies are compared in terms of the efficiency of the network design both from a cost and capacity point of view and in terms of the availability of the connections routed over this network. In order to be able to assess the network topologies under realistic circumstances, the expected traffic demand is forecasted. This enables to make the comparison for the current traffic volume as well as for the traffic patterns of the future. As not all types of (data) traffic require the same degree of survivability and in order to leverage the total capacity cost of the network design, a distinction is made between different recovery options in the optical layer for the different traffic types considered.     

Polarographische bestimmung von Diacetyl und Acetoin in butter

Zusammenfassung Diacetyl wird durch Wasserdampfdestillation aus dem Probenmaterial isoliert und in Acetatpuffer, pH 5,2 polarographisch mit dem Differential-Puls-Verfahren bestimmt. Acetoin wird durch Oxidation mit FeCl₃ in Diacetyl überführt und in gleicher Weise bestimmt.

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The polarographic determination of Diacetyl and Acetoin in butter

Summary Diacetyl is isolated from butter by steamdestillation and determined in acetate-buffer, pH 5,2, by differential-pulse-polarography. Acetoin ist oxidized to Diacetyl with FeCl₃ and then determined as described.

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Herrn Prof. Dr. Ing. Friedrich Asselmeyer zur Vollendung des 70. Lebensjahres gewidmet     

Does a cycle training course improve cycling skills in children?

Introduction

The aim of this study was to determine the short-term effects of cycle training on basic cycling skills in children from the 4th grade of elementary school. Furthermore, the influence of gender, socio-economic status (SES) and initial cycling skills level on the effects of the cycle training was investigated.

Methods

Five participating schools were randomly assigned to the intervention (n = 3) or control condition (n = 2). Children's cycling skills were assessed, using a practical cycling test, at baseline and immediately after the intervention. At baseline, all participating children received a short parental questionnaire on child's demographic and family factors. After the pre-test, cycle training took place only in the intervention schools. Repeated measure analyses were conducted to evaluate the effectiveness of the cycle training.

Results

The cycle training had a statistically significant effect on children's total cycling skill (F = 46.9, p < 0.001). On mounting the bicycle and start to cycle (F = 2.6, p = 0.11), cycling one handed (F = 2.0, p = 0.16), and cycling on a sloping surface (F = 1.5, p = 0.23), no statistically significant effects were detected. On all other cycling skills, time × condition interaction effects were statistically significant. Gender, SES and initial cycling skills level had no significant influence on the effects of the cycle training.

Conclusion

This study showed that a cycle training of only three sessions was effective to improve children's cycling skills at short term and that cycle training within a traffic-free environment seems to be a useful first step in the development of safe cycling behaviors.