A New Version of the Item Count Technique for Asking Sensitive Questions: Testing the Performance of the Person Count Technique

This paper presents empirical evidence on a recent advancement of the item count technique (ICT, a survey technique for asking sensitive questions), namely, the person count technique (PCT; Grant, Moon, & Gleason, 2014). PCT utilizes person lists instead of lists of filler questions, as is the case in the classic ICT design. This simplifies the questioning procedure, but leads to some methodological challenges such as floor and ceiling effects. The main part of this paper presents empirical evidence stemming from an experimental postal survey in Germany (N = 580) investigating how well PCT performs as compared to standard direct questioning (DQ) with regard to alleviating misreporting for questions on attitudes towards refugees. PCT prevalence estimates for hostile attitudes towards refugees are significantly higher than DQ estimates for one item, and non-significantly higher for three items. Although not consistently significant, the differences are substantial, amounting to a threefold increase of the proportion of respondents expressing negative attitudes towards refugees. Even though the findings are not unequivocally in favor of PCT, this new ICT variant still deserves consideration in the future and warrants further development. Specifically, more knowledge is required with respect to its statistical properties and the best practices of its implementation

The CRISPR/Cas revolution reaches the RNA world: Cas13, a new Swiss Army knife for plant biologists

Application of the bacterial CRISPR /Cas systems to eukaryotes is revolutionizing biology. Cas9 and Cas12 (previously called Cpf1) are widely used as DNA nucleases for inducing site‐specific DNA breaks for different kinds of genome engineering applications, and in their mutated forms as DNA ‐binding proteins to modify gene expression. Moreover, histone modifications, as well as cytosine methylation or base editing, were achieved with these systems in plants. Recently, with the discovery of the nuclease Cas13a (previously called C2c2), molecular biologists have obtained a system that enables sequence‐specific cleavage of single‐stranded RNA molecules. The latest experiments with this and also the alternative Cas13b system demonstrate that these proteins can be used in a similar manner in eukaryotes for RNA manipulation as Cas9 and Cas12 for DNA manipulations. The first application of Cas13a for post‐transcriptional regulation of gene expression in plants has been reported. Recent results show that the system is also applicable for combating viral infection in plants. As single‐stranded RNA viruses are by far the most abundant class of viruses in plants, the application of this system is of special promise for crops. More interesting applications are imminent for plant biologists, with nuclease dead versions of Cas13 enabling the ability to visualize RNA molecules in vivo , as well as to edit different kinds of RNA molecules at specific bases by deamination or to modify them by conjugation. Moreover, by combining DNA ‐ and RNA ‐directed systems, the most complex of changes in plant metabolism might be achievable

A two-person game on graphs where each player tries to encircle his opponent's men

AbstractWe present results on a combinatorial game which was proposed to one of the authors by Ingo Althöfer (personal communication). Let G be an undirected finite graph without loops and multiple edges and let k be a positive integer with k ⩽ 12(¦G¦ - 1). There are two players, called white and black, both having k men of their color. In turn, beginning with white, the players position their men one at a time on unoccupied vertices of G. When all men are placed, the players take turns moving a man of their color along an edge to an unoccupied adjacent vertex (again beginning with white). A player wins if his opponent cannot carry out his next move since none of his men has an unoccupied neighbor. If the game does not stop, then the outcome is a draw. We always assume that both players play optimal. Among other questions, we deal with the following ones: 1.1. Is it true that, for all G and k, white cannot win the game?2.2. Does there exist a tree T and a positive integer k for which the outcome is a draw? Let τ(G) denote the covering number of G, i.e., τ(G) is the minimum number of vertices covering all edges of G. We prove that black wins the game if τ(G) ⩽ k. We use this result to show that white never wins the game if Gis bipartite, thus providing a partial answer to the first question. We answer the second question in the affirmative by constructing an infinite series of trees for which the outcome is a draw (for some k). Moreover, we present results on extremal problems arising in the context of the game. We also completely solve the cases when G is a path or a cycle. Further, we completely settle the case k ⩽ 2. In the proofs of our results, matchings and cycles in graphs play a predominant role

Competence Assessment in Higher Education. A Pilot Study on the Measurement of Competencies in Empirical Social Research Methods among University Students

In the general education system, standardized competence assessment of students are by now well established (cf. the PISA studies). As concerns the higher education sector, however, evaluation of student achievement is still mostly based on subjective indicators or on indicators that measure input into the educational system (e.g., the funding of universities), although research has clearly pointed out the flaws of this practice. Given the general demand for an objective, standardized competence assessment among university students, it is astonishing that especially in sociology, a discipline which is supposedly sensible for the need of valid measurement instruments and at the same time has the methodological competency to develop them, virtually no research has focused on this issue yet. Our article is intended to start filling this gap. We present results from a pilot study devoted to the definition and measurement of competencies in quantitative empirical social research methods - a core sub-discipline of all social sciences which is particularly well suited for competence measurements - among university students. For this purpose, we present a structural competence model, that was operationalized into test items which were administered to 776 sociology students in Germany and Switzerland. The resulting data were scaled into competence indicators using methods of item response theory. The resulting indicators show satisfactory scale properties and good external validity. Content-related analyses on determinants of student achievement, as measured by the competence indicators, show a fruitful analysis potential of the data. All in all, the results are in favor of further pursuing competence assessments of university students in sociology. For this goal, however, several problems that we also discuss in the paper have to be addressed in the future

Cost and Benefit of Apprenticeship Training: A Comparison of Germany and Switzerland

For the first time it has been made possible to merge a German and a Swiss firm-level data set that include detailed information about costs and benefits of apprenticeship training. Previous analyses based only on aggregate data showed that the net costs of training apprentices are substantial in Germany, whereas apprenticeship training is on average profitable during the training period for firms in Switzerland, even though the two training systems are rather similar. This paper analyzes the reasons for these differences with matching methods. We simulate the impact of changes in certain parameters such as wages, apprenticeship system-related factors and allocation of tasks to apprentices on the cost-benefit ratio using the counterfactual values of the other country. The results show that most of the difference in the net costs of training between the two countries can be explained by a higher share of productive tasks allocated to apprentices in Switzerland and the differences in relative wages.apprenticeship training, cost and benefit analysis

Discriminatory Residential Preferences in Germany - A Vignette Study

The article focusses on the generating mechanisms of residential segregation for the demand side of housing markets, i.e., discriminatory residential preferences of inhabitants regarding the composition of their neighborhood. The data stem from an online survey among a random sample of the population of a mid-sized German city. In a vignette experiment, respondents were asked to rate example residential settings with respect to their attractiveness. The settings varied regarding the ethnic and religious composition of the neighborhood and other neighborhood characteristics that are positively or negatively related to residential attractiveness.We find that respondents have discriminatory residential preferences toward migrants and the presence of a Muslim community in the neighborhood. One-half of the migrant effect is mitigated if other positively connoted residential characteristics exist. We take this as an indication for statistical discrimination. This does not hold for the “Muslim community” effect. Discrimination gets stronger with higher levels of perceived economic group-threat from migrants. We further find evidence for a cultural group-threat and for the contact hypothesis: religious people are more discriminatory than nonreligious people, and real-life contact with migrants entails less discrimination

Wavelet-Packet Powered Deepfake Image Detection

As neural networks become more able to generate realistic artificial images, they have the potential to improve movies, music, video games and make the internet an even more creative and inspiring place. Yet, at the same time, the latest technology potentially enables new digital ways to lie. In response, the need for a diverse and reliable toolbox arises to identify artificial images and other content. Previous work primarily relies on pixel-space CNN or the Fourier transform. To the best of our knowledge, wavelet-based gan analysis and detection methods have been absent thus far. This paper aims to fill this gap and describes a wavelet-based approach to gan-generated image analysis and detection. We evaluate our method on FFHQ, CelebA, and LSUN source identification problems and find improved or competitive performance.Comment: Source code is available at https://github.com/gan-police/frequency-forensic

Does the class teacher make a defference? School recommendations and educational opportunities of elementary school students

Haben Lehrermerkmale zusätzlich zu den vielfach bestätigten Effekten der sozialen Herkunft einen Einfluss auf die ungleichen Bildungschancen von Grundschüler/inne/n? Hierzu untersucht der Beitrag den Einfluss (a) des Geschlechts, (b) der Berufserfahrung und (c) des Studienfaches der Klassenlehrer/innen auf die Wahrscheinlichkeit, dass ein/e Schüler/in eine Gymnasialempfehlung erhält. Als Datengrundlage dient eine Befragung aller Schüler/innen der vierten Klassen an Wiesbadener Grundschulen sowie deren Eltern und Klassenlehrer/innen. Die Ergebnisse zeigen, dass die Chancen eines Schülers bzw. einer Schülerin, eine Gymnasialempfehlung zu erhalten, bei gleicher Note umso höher sind, je häufiger ein/e Klassenlehrer/in bereits Übergänge von vierten Klassen in die Sekundarstufe I betreut hat. Des Weiteren sind die Chancen für eine Gymnasialempfehlung bei Schüler/inne/n mit einem Deutschlehrer bzw. einer Deutschlehrerin als Klassenlehrer/in niedriger, wobei dies auf die höhere Gewichtung der Deutschnote durch die Deutschlehrer/innen zurückzuführen ist. Das Lehrergeschlecht wirkt sich dagegen weder separat noch in Interaktion mit dem Schülergeschlecht auf die Wahrscheinlichkeit aus, eine Gymnasialempfehlung zu erhalten. Der vorliegende Beitrag will eine erste Bestandsaufnahme zum Thema "Lehrkräfte und Bildungschancen" leisten, ohne das seit langem praktizierte Selektionsverfahren mit seinen Schwierigkeiten legitimieren zu wollen. Eine objektive Beschreibung des Ist-Zustandes zum Entscheidungshandeln relevanter Akteure beim Übergang von der Primar- in die Sekundarstufe ist für die weitere Diskussion unabdingbare Voraussetzung. (DIPF/Orig.)Do teacher variables have an influence on inequal educational opportunities of elementary school students, in addition to the multiple proven impacts of the social background? This article deals with the influence of a class teacher\u27s (a) gender, (b) professional experience, and (c) main subject on the probability that a student gets a recommendation for grammar school. It is based on the results of a survey of all fourth graders at Wiesbaden elementary schools, their parents, and their teachers. The results indicate that a student\u27s chances to get a recommendation for grammar school in case of equal school grades are the better, the more oft en a class teacher has already been in charge of the transition of fourth graders to secondary schools. Moreover, the chances to get a recommendation for grammar school get worse for students whose class teacher is a German teacher because he lays more stress on the grade in German. The teachers\u27 gender has no effect on the probability to get a recommendation for grammar school however, neither separately nor in relation to the students\u27 gender. Though the selection process which has been practiced for a long time shall not be legitimized, this article will give a first stocktaking of the issue "teachers and educational opportunities". An objective description of the actual state of decision-making of the relevant players is an indispensable pre-condition for further discussion. (DIPF/Orig.

Model-Based Control Design of an EHA Position Control Based on Multicriteria Optimization

For the control of dynamic systems such as an Electro-Hydraulic Actuator (EHA), there is a need to optimize the control based on simulations, since a prototype or a physical system is usually not available during system design. In consequence, no system identification can be performed. Therefore, it is unclear how well a simulation model of an EHA can be used for multicriteria optimization of the position control due to the uncertain model quality. To evaluate the suitability for control optimization, the EHA is modeled and parameterized as a grey-box model using existing parameters independent of test bench experiments. A method for multi-objective optimization of a controller is used to optimize the position control of the EHA. Finally, the step responses are compared with the test bench. The evaluation of the step responses for different loads and control parameters shows similar behavior between the simulation model and the physical system on the test bench, although the essential phenomena could not be reproduced. This means that the model quality achieved by modeling is suitable as an indication for the optimization of the control by simulation without a physical system

Characterization of paired Cas9 nickases induced mutations in maize mesophyll protoplasts

Targeted genome modifications are important for both fundamental and applied research. The CRISPR/Cas9 (clustered regularly interspaced short palindromic repeats / CRISPR-associated protein 9) technology has been successfully used in various plant species with high efficiency. Approaches with paired Cas9 nickase enhance the specificity of the CRISPR/Cas9 system by using guide RNA pairs to create two staggered single strand breaks on complementary DNA strands. Here we used maize mesophyll protoplasts as a transient test system and demon- strated the mutagenic potential of Cas9 nickases. Although we found activity for all the three different guide RNA pairs tested, their efficiency varied considerably. Characterization of the modification events revealed a high ratio of large deletions as well as insertions of donor DNA fragments. By the use of the maternally expressed in embryo 1 gene (mee1) as model target sequence, we could demonstrate that transcriptionally inactive and methylated genomic loci are practical targets of Cas9 nickase. The high specificity of Cas9 nickase approaches might provide advantage for genome modifications of certain loci in the complex and highly repetitive maize genome