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Stratification is an important design feature of many studies using complex sampling designs and it is often used in large-scale assessment (LSA) studies, such as the Programme for International Student Assessment (PISA), for two main reasons. First, stratification variables that achieve a high between and low within strata variance can improve the efficiency of a survey design. Second, stratification allows one to, explicitly or implicitly, control for sample sizes across subpopulations. It ensures that some parts of a population are in the sample in predetermined proportions. In this study, we determine through simulation which stratification scheme is best for PISA in Germany. For this, we consider the constraints imposed by the international sampling design, the available information about schools, and specific national characteristics of the German educational system. We examine seven different stratification designs selected based on scenarios used in past LSAs in Germany and theoretical considerations for future implementations. The chosen scenarios were compared with two reference scenarios: (1) an unstratified design and (2) a synthetic optimal stratification design. The simulation study reveals that the stratification design currently applied in PISA produces satisfactory results regarding sampling precision. The present stratification design is based on Germany's federal states and school types. However, this approach leads to small strata, which has been problematic for estimating sampling variance in previous cycles. Therefore, alternative stratification scenarios were considered and, in addition to overcoming the small-strata problem, also led to smaller standard errors for estimates of student mean performance in mathematics, science, and reading. As a result of this study, we recommend considering three different stratification designs for Germany in future cycles of PISA. These recommendations aim to: (1) improve the sampling efficiency while keeping the sample size constant, (2) follow a sound methodological approach, and (3) make conservative and cautious changes while maintaining a reflection of the structure of the German federal school system with different school types. These suggestions include a reinvented stratification of grouped German federal states and designs with school types as explicit stratifiers and federal states as implicit stratifiers. [ABSTRACT FROM AUTHOR]

The aim of this study was to compare surface roughness of three different types of chairside monolithic ceramic and ceramic-like CAD/CAM restorative materials finished and polished with two)stage diamond impregnated polishing disc systems. before- and after- clinician experience. For each test material such as: glass ceramic (VITA Mark II, VITA-Zahnfabric, Bad Sackingen, Germany), polymer infiltrated ceramic (VITA Enamic, VITA-Zahnfabric, Bad Sackingen, Germany), nano hybrid ceramic (Lava Ultimate, 3M-ESPE, Seefeld, Germany), 20 disc shaped specimens (radius=10mm, thickness=2mm) were prepared. Then each test groups were subdivided into two groups depending on operator’s experience. Finishing and polishing procedure was achieved before (n=10) and after (n=10) experience of operator, respectively. Average surface roughness (Ra) measurement were obtained using a surface profilometer. For each test group ten specimens were prepared and roughness was measured in five different positions using a profilometer with a traversing distance of 4 mm and a cut-off value of 0.8mm. The radius of the tracing diamond tip was 5µm and measuring force and speed was 4mN and 0.5 mm/s, respectively. The surface roughness of each individual disk was taken as the arithmetic mean of the Ra values measured in five different positions. It can be concluded that finishing and polishing of ceramic and ceramic-like CAD/CAM restorative materials are dependent both material structure and experience of operator. [ABSTRACT FROM AUTHOR]

In this paper, we present the currents, which have been measured since 2008 at the new top structure of the Peissenberg Tower, Germany, and the associated electric fields in a distance of about 180 m from the tower. The study comprises 17 negative lightning, which contained 44 subsequent return strokes, 108 initial continuous current (ICC)-pulses, and 26 M-components. The analysis, based on the current waveform, revealed three different types for both the M-component current and the ICC-pulse. The impulsive current of type 1 has a more or less symmetrical wave shape. For this type, the electric field occurred on average 15.7 μs prior to the current pulse. The impulsive current of type 2 has a bipolar wave shape with current reversal. The impulsive current of type 3 has a wave shape, which exhibits a fast rise to peak and a much longer decay to low current values. For all types of impulsive currents (return strokes, ICC-pulses, and M-components), the electric field exhibits a first field change (ΔE1) followed by a second field change (ΔE2) of opposite polarity. For the ICC-pulses and M-component currents of types 1 and 3, the first field change (ΔE1) has typically an initial slow-rising section, which is followed by a fast-rising section. The transition point was time-correlated with the onset of the current. The transition point was at about ΔE1/3 for type 1 and at about ΔE1/2 for type 3. For type 2, the onset of the current pulse occurred during the second field change (ΔE2) of opposite polarity. Similar to type 1 and 3 pulses, the slow-rising electric field changed into a fast-rising electric field. The transition point for type 2 pulse was at about ΔE2/3. From the 44 subsequent return strokes, 8 of them contained one negative M-component of type 1. In that case, the M-component current was extremely strong. The arithmetic mean (AM) was 8.5 kA (GM: 5.4 kA) for the peak current and 747.8 mC (GM: 614.0 mC) for the transferred charge. The return stroke was also very strong, with an AM of 16.7 kA for the peak current (GM: 15.0 kA). In comparison, the AM was 10.4 kA (GM: 8.3 kA) considering all subsequent return strokes. [ABSTRACT FROM AUTHOR]

Background. Between 2008 and 2011 about 40 cases of human cowpox were reported from Germany and France. Infections had been acquired via close contact to infected, young pet rats. An identical and unique sequence of the hemagglutinin gene was found in various cowpox virus (CPXV) isolates pointing to a common source of infection. In a second CPXV outbreak in cats in a small animal clinic in Germany in 2015, four out of five hospitalized cats showed identical hemagglutinin sequences and thus, a hospitalacquired transmission had been assumed. Next-Generation Sequencing was performed in order to re-investigate the outbreaks, as epidemiological data could not confirm all cases. Methods. Homogenates of lesion material from rats, cats and humans were cultivated in cell culture. The genomes of four virus isolates, nine CPXVs from our strain collections and from DNA of three paraffin-embedded lesion materials were determined by Next Generation Sequencing (NGS). For phylogenetic analyses a MAFFT-alignment was generated. A distance matrix based on concatenated SNPs was calculated and plotted as dendrogram using Unweighted Pair Group Method with Arithmetic mean(UPGMA) for visualization. Results. Aligning of about 200.000 nucleotides of 8 virus isolates associated with the pet rat outbreak revealed complete identity of six genomes, the remainder two genomes differed in as little as 3 SNPs. When comparing this dataset with four already published CPXV genomes also associated with the pet rat outbreak, again a maximum difference of 3 SNPs was found. The outbreak which lasted from 2008 till 2011 was indeed caused by a single strain which has maintained an extremely high level of clonality over 4 years. Aligning genomic sequences from four cases of feline cowpox revealed 3 identical sequences and one sequence which differed in 65 nucleotides. Although identical hemagglutinin sequences had been obtained from four hospitalized cats, genomic sequencing proved that a hospital-acquired transmission had occurred in only three cats. Conclusion. Analyzing the rather short sequence of the hemagglutinin gene is not sufficient to conduct molecular trace back analyses. Instead, whole genome sequencing is the method of choice which can even be applied to paraffin-embedded specimens. [ABSTRACT FROM AUTHOR]

Aim of the article is to find out the causal relationship between dimensions of market orientation (MO) and innovation (INOV). Market orientation was studied as a four-dimensional construct and innovation as a onedimensional. Market orientation in this study is understood as a process of getting information about customers and competitors, spreading and integrating these information within the company and reactions to these information in the form of a coordinated actions. The studied sample was represented by the Czech (N=164) and German (N=187) high-tech firms in manufacturing industries. Selection of firms was carried out in Albertina and Hoppenstedt database. Respondents in managerial ranks completed the questionnaire and marked their rate of approval with individual statements on a seven point Likert scale. The way to achieve the goals is to quantify market orientation by constructing indices of market orientation. Index of market orientation and innovation was calculated as an arithmetic mean of the measured values. The main method to reach the target was multiple regression analysis. The research confirmed hypothesis about existence of the relation between three dimensions of market orientation - customer intelligence generation (CUIG), intelligence dissemination & integration (IDI), responsiveness to market intelligence (RMI) and innovation in Czech Republic and Germany. No significant relationship was detected between dimension competitor intelligence generation (COIG) and innovation in either of the two countries. [ABSTRACT FROM AUTHOR]

This paper analyzes the slow-varying electric fields and the associated currents of a total of 35 negative upward lightning initiated by the Peissenberg tower, Germany. Thirty-four of which were from winter upward lightning and only one from summer upward lightning. It appears that all of the winter upward lightning were initiated without nearby preceding lightning activity (called “self-initiated” lightning) and only the summer lightning was triggered by nearby lightning activity (called “other-triggered” lightning). The slow-varying electric fields of the winter upward lightning showed a fast rise characterized by the 10–90% risetime, with an arithmetic mean of 13.8 ms. After attaining the maximum, the electric field turned into a slow decay being characterized by the time on half value which was evaluated to having the arithmetic mean of 441 ms. Transported charges to ground were on average 44.8 C and on maximum 165 C. The maximum value of the electric field was 39.9 kV/m on average, with the highest value being 64.5 kV/m. For the electric fields, higher values were prevented by recovery effects such as the corona from objects at ground and the redistribution of the charge in the thundercloud. Due to these effects, no or only weak correlations were found between the 10–90% risetime, the time on half value, the charge, and the maximum of the electric field. From additional measurements with a field mill, it was found that the electric field recovers to the starting level within some seconds. [ABSTRACT FROM PUBLISHER]

Radiological assessment of the mineralization stage of third molars is a major criterion for age estimation of living people involved in criminal proceedings. To date insufficient knowledge has been obtained about how the ethnic origin can influence tooth mineralization. A comparative study of wisdom tooth mineralization was carried out on three population samples: one German, one Japanese and one South African. To this end, 3,652 conventional orthopantomograms were evaluated on the basis of Demirjian?s stages. The Japanese subjects were on average 1?2 years older than their German counterparts upon reaching stages D?F, whereas the South African subjects were on average 1?2 years younger than the Germans when displaying stages D?G. To enhance the accuracy of forensic age estimates based on wisdom tooth mineralization we recommend the use of population-specific standards. [ABSTRACT FROM AUTHOR]

2-Mercaptobenzothiazole (2-MBT) is widely used as a vulcanisation accelerator and is contained in many products made from natural rubber, e.g. car tires. Additionally, it is used as a fungicide in paint or fibre. Systemically human exposure to 2-MBT can occur via dermal and oral uptake or inhalation. Locally, 2-MBT can cause skin sensitisation. The International Agency for Research on Cancer (IARC) classified 2-MBT as probably carcinogenic to humans. 516 urine samples of 3- to 17-year-old children and adolescents living in Germany were analysed for the concentration of 2-MBT in the population representative German Environmental Survey for Children and Adolescents 2014-2017 (GerES V). 2-MBT was quantified above the limit of quantification (LOQ) of 1.0 μg/L in 50% of the 516 samples analysed. The geometric mean of urinary 2-MBT concentration was 1.018 μg/L and 0.892 μg/gcreatinine, the arithmetic mean was 1.576 μg/L (1.351 μg/gcrea). The median concentration was below the LOQ. Analyses of subgroups revealed higher 2-MBT concentrations in children aged 3-5 years compared to 14- to 17-year-old adolescents. All urinary 2-MBT concentrations were well below the health-based guidance value HBM-I for children of 4.5 μg/L. Therefore, current exposure levels are - according to current knowledge - not of concern. For the first time, reference values can be derived for 2-MBT for children and adolescents in Germany. This will facilitate to recognise changing exposure levels in this population group in Germany and identification of unusually high exposures. [ABSTRACT FROM AUTHOR]