Analysis of texture and connected-component contours for the automatic identification of writers

Recent advances in "off-line" writer identification allow for new applications in handwritten text retrieval from archives of scanned historical documents. This paper describes new algorithms for forensic or historical writer identification, using the contours of fragmented connected-components in free-style handwriting. The writer is considered to be characterized by a stochastic pattern generator, producing a family of character fragments (fraglets). Using a codebook of such fraglets from an independent training set, the probability distribution of fraglet contours was computed for an independent test set. Results revealed a high sensitivity of the fraglet histogram in identifying individual writers on the basis of a paragraph of text. Large-scale experiments on the optimal size of Kohonen maps of fraglet contours were performed, showing usable classification rates within a non-critical range of Kohonen map dimensions. The proposed automatic approach bridges the gap between image-statistics approaches and purely knowledge-based manual character-based methods

Using longitudinal targeted maximum likelihood estimation in complex settings with dynamic interventions.

Longitudinal targeted maximum likelihood estimation (LTMLE) has very rarely been used to estimate dynamic treatment effects in the context of time-dependent confounding affected by prior treatment when faced with long follow-up times, multiple time-varying confounders, and complex associational relationships simultaneously. Reasons for this include the potential computational burden, technical challenges, restricted modeling options for long follow-up times, and limited practical guidance in the literature. However, LTMLE has desirable asymptotic properties, ie, it is doubly robust, and can yield valid inference when used in conjunction with machine learning. It also has the advantage of easy-to-calculate analytic standard errors in contrast to the g-formula, which requires bootstrapping. We use a topical and sophisticated question from HIV treatment research to show that LTMLE can be used successfully in complex realistic settings, and we compare results to competing estimators. Our example illustrates the following practical challenges common to many epidemiological studies: (1) long follow-up time (30 months); (2) gradually declining sample size; (3) limited support for some intervention rules of interest; (4) a high-dimensional set of potential adjustment variables, increasing both the need and the challenge of integrating appropriate machine learning methods; and (5) consideration of collider bias. Our analyses, as well as simulations, shed new light on the application of LTMLE in complex and realistic settings: We show that (1) LTMLE can yield stable and good estimates, even when confronted with small samples and limited modeling options; (2) machine learning utilized with a small set of simple learners (if more complex ones cannot be fitted) can outperform a single, complex model, which is tailored to incorporate prior clinical knowledge; and (3) performance can vary considerably depending on interventions and their support in the data, and therefore critical quality checks should accompany every LTMLE analysis. We provide guidance for the practical application of LTMLE

Has the Covid-19 pandemic led to more informal and decentralised EU decision-making?

Covid-19 has presented unprecedented challenges for the EU’s member states. Drawing on a new study, Rahel M. Schomaker, Marko Hack and Ann-Katrin Mandry take stock of the EU’s reaction to the first wave of the pandemic. They write the response was characterised by shifts between forms of centralisation and decentralisation, as well as formal and informal decision-making

Predicting the unknown:Novelty processing depends on expectations

Fulfilled predictions lead to neural suppression akin to repetition suppression, but it is currently unclear if such effects generalize to broader stimulus categories in the absence of exact expectations. In particular, does expecting novelty alter the way novel stimuli are processed? In the present study, the effects of expectations on novelty processing were investigated using event-related potentials, while controlling for the effect of repetition. Sequences of five stimuli were presented in a continuous way, such that the last stimulus of a 5-stimulus sequence was followed by the first stimulus of a new 5-stimulus sequence without interruption. The 5-stimulus sequence was predictable: the first three stimuli were preceded by a cue indicating that the next stimulus was likely to be a standard stimulus, and the last two by a cue indicating that the next stimulus was likely to be novel. On some trials a cue typically predicting a standard was in fact followed by an unexpected novel stimulus. This design allowed to investigate the independent effects of (violated) expectations and repetition on novelty processing. The initial detection of expected novels was enhanced compared to unexpected novels, as indexed by a larger anterior N2. In contrast, the orienting response, as reflected by a novelty P3, was reduced for expected compared to unexpected novels. Although the novel stimuli were never repeated themselves, they could be presented after one another in the sequence. Such a category repetition affected the processing of novelty, as evidenced by an enhanced anterior N2, and a reduced novelty P3 for novels preceded by other novels. Taken together, the current study shows that novelty processing is influenced by expectations

Light Scattering of High Polymer Solutions

In principle it is possible to determine the molecular weight distribution of a high polymer, containing no excessively large molecules, from interpretation of its light scattering in solutions at various concentrations. Actually there appear to be severe limitations to this method. Not only is it evident that, considering experimental error, the resolving power is low for the detection in any part of the molecular weight distribution curve of a group of components of similar molecular weights (as contrasted to a single component), it may also happen, in consequence of the restriction of the data to a certain concentration range, that components at the ends of the distribution curve will not be detected and, moreover, that the conclusions regarding the remainder of the distribution will be distorted

Dinitrogen or dichloromethane?

A recent article in this journal reports the crystal structure of (octaethylazaporphyrinato)iron(III) chloride, (OEP)Fe^(III)-Cl·CH_2Cl_3·N_2, at 130 K, in which the N_2 molecule is referred to as "unusual, but no other explanation for two equal-sized atoms separated by 1.21 (2) Å. could be found". Even more unusual is a "close contact" of 1.86 Å between two such molecules (related by a center of symmetry), forming an angle N-N≡N of 109° and thus leading to a sort of perazabuta-1,3-diene molecule. If this were a genuine new tetranitrogen molecules so gently produced, it would be a remarkable discovery, worth celebrating as a milestone in synthetic and structural chemistry and in nitrogen fixation. Since we were skeptical of the ability of these crystals, which were grown at room temperature, to capture and contain a nitrogen molecule (and to cause it to dimerize as well), we have undertaken a re-examination of the structure. Perhaps unfortunately, we have concluded that the earlier interpretation as dinitrogen is erroneous

What I see is what I want: top-down attention biasing choice behavior

Health and self-regulatio

Healthy or not: influencing attention to bias food choices

Health and self-regulatio

Concept dialogues as an instrument for inclusive diagnostics? Recording childlike preconceptions, ideas and justifications in the problem-solving process - using the phenomenon of bridging stability as an example

Im Rahmen des Beitrages werden Ergebnisse aus der Analyse von Interviews mit Kindern auf Basis eines Konzeptdialogs zum Phänomen Stabilität von Brücken vorgestellt. Fokussiert werden dabei die kindlichen Präkonzepte und Vorstellungen zu diesem Phänomen sowie die Begründungen, die die Kinder zur Lösung der Problemstellung Bau einer Brücke aus Papier vornehmen. Anknüpfend an diese Ergebnisse werden – im Sinne einer inklusiven Diagnostik – unterschiedliche Lernvoraussetzungen abgeleitet sowie die sich daraus ergebenden Anknüpfungspunkte und Erweiterungen für einen inklusiven Sachunterricht vorgestellt. Abschließend wird auf Basis der Ergebnisse diskutiert, welche Schlussfolgerungen für die Qualifizierung von Lehrkräften gezogen werden können, um so zu einem differenzierteren Verständnis inklusiver Diagnostik beitragen zu können. (DIPF/Verlag)As part of the contribution, results from the analysis of interviews with children on the basis of a conceptual dialogue on the phenomenon of bridging stability are presented. The focus is on the childlike preconceptions and ideas about this phenomenon, as well as the reasons the children give to solve the problem of building a bridge out of paper. Based on these results in the sense of an inclusive diagnosis different learning prerequisites are derived and the resulting connecting point and extensions for an inclusive Sachunterricht are presented. Finally, on the basis of the results, it is discussed which conclusions can be drawn for the qualification of teachers in order to contribute to a more differentiated understanding of inclusive diagnostics