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International audience; Poly(ADP-ribose) polymerase 1 (PARP1) activity is regulated by its co-factor histone poly(ADP-ribosylation) factor 1 (HPF1). The complex formed by HPF1 and PARP1 catalyzes ADP-ribosylation of serine residues of proteins near DNA breaks, mainly PARP1 and histones. However, the effect of HPF1 on DNA repair regulated by PARP1 remains unclear. Here, we show that HPF1 controls prolonged histone ADP-ribosylation in the vicinity of the DNA breaks by regulating both the number and length of ADP-ribose chains. Furthermore, we demonstrate that HPF1-dependent histone ADP-ribosylation triggers the rapid unfolding of chromatin, facilitating access to DNA at sites of damage. This process promotes the assembly of both the homologous recombination and non-homologous end joining repair machineries. Altogether, our data highlight the key roles played by the PARP1/HPF1 complex in regulating ADP-ribosylation signaling as well as the conformation of damaged chromatin at early stages of the DNA damage response.

A multiplicity of simulations is required to optimize systems with thermal transient processes in the presence of uncertain parameters. That is why model order reduction is applied to minimize the numerical effort. The consideration of heat radiation and convection with parameter-dependent heat transfer coefficients results in a nonlinear system with many inputs as these loads are distributed over the whole surface limiting the attainable reduced dimension. Therefore, a new input reduction method is presented approximating the input matrix based on load vector snapshots using singular value decomposition. Afterward, standard reduction methods like the Krylov subspace method or balanced truncation can be applied. Compared to proper orthogonal decomposition, the number of training simulations decreases significantly and the reduced-order model provides a high accuracy within a broad parameter range. In a second step, the discrete empirical interpolation method is used to limit the evaluation of the nonlinearity to a few degrees of freedom and proper orthogonal decomposition allows the fast adaptation of the emissivity. As a result, the reduced system becomes independent of the original dimensions and the computation time is reduced drastically. This approach enables an optimal method combination depending on the number of simulations performed with the reduced model.

In this work, we focus on outdoor lighting estimation by aggregating individual noisy estimates from images, exploiting the rich image information from wide-angle cameras and/or temporal image sequences. Photographs inherently encode information about the scene's lighting in the form of shading and shadows. Recovering the lighting is an inverse rendering problem and as that ill-posed. Recent work based on deep neural networks has shown promising results for single image lighting estimation, but suffers from robustness. We tackle this problem by combining lighting estimates from several image views sampled in the angular and temporal domain of an image sequence. For this task, we introduce a transformer architecture that is trained in an end-2-end fashion without any statistical post-processing as required by previous work. Thereby, we propose a positional encoding that takes into account the camera calibration and ego-motion estimation to globally register the individual estimates when computing attention between visual words. We show that our method leads to improved lighting estimation while requiring less hyper-parameters compared to the state-of-the-art., Comment: 11 pages, 7 figures, 1 table, currently under a review process

Welded hollow sections are typical in different industries. A database of fatigue life data of welded hollow section joints covering sequence effects and the accuracy of the linear damage accumulation is presented. The effects of the shape of the applied load spectra, sequence effects of different amplitudes have been investigated using two high-strength steels. This document covers thin-walled tubes of 2-mm thickness made of low-carbon or mild steel 1.8849 (S460MH) and austenitic TWIP-steel 1.4678 + CP700 (X30MnCrN16-14). Constant amplitude and two-level load spectra are presented to check the linear damage accumulation. Using stress concentration factors from finite element analysis, typical FAT classes for the structural and the effective notch stress concepts are checked as well. Both structures show much higher strength compared IIW recommendations by structural stress approach and DVS 0905 by effective notch stress approach. Typical maximum linear damage sums taken from recommendations and codes of 0.2 or 0.5 are exceeded for all spectra investigated and in some of the cases even significantly above 1.0. Transferability of the recommendations to component type structures like those tubular joints made of high-strength steel needs revision to lift its lightweight potential but this will require additional data.

The effective notch stress approach to estimate fatigue strength of welded components requires stress concentration factors of an idealized weld geometry using fictitious notch radii. This paper covers the estimation of those stress concentration factors for welded T-joints in different configurations. In comparison with different existing estimations, new methods using metamodeling by (a) the response surface method based on polynomial regression using coupling terms and (b) based on artificial neural networks are presented. The methods were trained by a large database of reference results obtained by finite element analysis. Besides higher quality of prognosis, the new metamodels enhance the range of allowable parameters of the T-joints compared to existing ones. The resulting methods provide means of obtaining stress concentration factors fast and of sufficient quality which could also be embedded in more complex applications as programmed solutions.

This paper presents the influences of the irregularity “insufficient penetration welding” on the fatigue strength based on experimental and numerical investigations. For this purpose, the fatigue strength of partial penetration butt welds of mild steel (S355) with different non-welded gaps were subjected to fatigue loading. Three different planned gap dimensions (h = 4, 6, 8 mm) at one-sided (Y-seam) and two-sided (DY-seam) partial penetration butt welds were analysed. The results were obtained on a small-scale test specimen with a steel plate thickness of t = 20 mm, without axial and angular misalignment. For the numerical effective notch stress approach, regression formula for efficient analysis of stress concentration factors was determined. The results show that butt joints which are not fully penetrated on one or both sides, and which were previously not permissible for welded joints subject to fatigue loading, can be evaluated in the future on the basis of these investigations.

Background Poisoning of children after exposure to pesticides is a major public health concern, particularly in countries with poorer urban populations, such as South Africa. This may stem from the illegal distribution and domestic use of street pesticides, which are highly hazardous agricultural pesticides. The aim of this study was to profile paediatric deaths due to acute pesticide poisoning in the west-metropole of Cape Town, South Africa; to identify whether the active ingredients were highly hazardous pesticides according to the FAO and WHO; and to inform policy and public health interventions to prevent future exposures and mortality. Methods A retrospective and descriptive analysis of forensic post-mortem records (2010 to 2019) was conducted to identify cases of paediatric deaths ( Results In total, 54 paediatric pesticide deaths were identified, including 22 (40.7%) males and 32 (59.3%) females, out of 5,181 paediatric unnatural deaths admitted over the 10-year period. The median age of the decedents was 8.3 years (range: 1 day to 17.9 years), with the majority under five years (42.6%) or between 15 and 18 years old (40.7%). All incidents occurred in peri-urban areas of Cape Town, with most individuals being admitted to hospital (88.9%) for a median survival time of 4.8 h. Toxicological analysis was requested in 50 cases (92.6%) with the organophosphate pesticides terbufos (n = 29), methamidophos (n = 2) and diazinon (n = 2) detected most frequently. Adolescent (15–18 years) suicides (29.6%) and accidental child deaths ( Conclusions Terbufos and methamidophos are highly hazardous pesticide (HHP) active ingredients registered in South Africa for agricultural uses, yet commonly sold as street pesticides for domestic use in lower socioeconomic areas. Reducing access and availability of toxic pesticides, especially through the illegal selling of street pesticides, and providing low toxic alternatives to poorer communities, may support mortality reduction initiatives. Mortality and toxicology data provide important, often overlooked, surveillance tools for informing policy and public health interventions to reduce toxic pesticide harm in local communities.

ZusammenfassungDie medienpädagogische Kompetenz angehender Lehrkräfte für die Primarstufe ist bislang nur ansatzweise erforscht und erfordert spezifische Zugänge. Die hier vorgestellte quantitative Studie gibt einen Einblick, mit welchen mediendidaktischen Überzeugungen und motivationalen Orientierungen als zentrale und handlungsrelevante Bereiche professioneller Kompetenz Studierende der Grundschuldidaktik (N = 344) ins Lehramtsstudium starten, wie diese Konstrukte miteinander in Verbindung stehen und welche Prädiktoren dafür identifiziert werden können. In der Befragung wird das Tablet als exemplarisches digitales Endgerät gewählt. Die Ergebnisse zeigen, dass sich die angehenden Lehrkräfte als kompetent im Umgang mit dem Tablet einschätzen und dem Tableteinsatz in der Schule tendenziell positiv gegenüberstehen, wohingegen sie diesen im Kontext des Anfangsunterrichts kritisch sehen.

ZusammenfassungIm Beitrag wird anhand von Daten der Studien StEG‑S und StEG-Tandem mit einem Mixed Method-Ansatz untersucht, wie Schüler*innen Hilfestellung in der Hausaufgabenbetreuung und Lernzeiten wahrnehmen. Die Forschung zu Hausaufgaben und individuellem Unterricht zeigt, dass Lehrkräfte vor der Herausforderung stehen, Schüler*innen zeitgleich Hilfe zukommen zu lassen, was potenziell eher für leistungsschwächere Schüler*innen ohne familiale Unterstützung relevant wäre. Empirisch zeigen sich jedoch keine Teilnahmeunterschiede an der Hausaufgabenbetreuung nach Leistungen und sozialer Herkunft, wie mithilfe von Daten der beiden Studien analysiert wird. Mittels Latenter Profilanalysen werden drei Profile der wahrgenommenen Hilfe der Schüler*innen auf Basis StEG-Tandem Daten dargestellt – wenig, mittlere und viel Hilfe. Diese Profile unterscheiden sich nicht in ihrer Zusammensetzung hinsichtlich Leistung und sozialer Differenzkategorien. Ferner zeigt die Auswertung der neun Gruppendiskussionen der StEG-Tandem Daten mit je drei bis acht Schüler*innen, dass das Warten auf Hilfe eher kein Problem darstellt und sie bei der Aufgabenbearbeitung nicht zwingend Hilfe benötigen bzw. nicht von allen ‚echte‘ Hilfe erhalten.

Zusammenfassung Hintergrund Bereits vor der Coronapandemie waren pflegende Angehörige mit einer Vielzahl an Herausforderungen und Belastungen konfrontiert. Erste Onlineerhebungen zeigten eine Zunahme der Pflegebelastung während der Pandemie. Ergänzend hierzu wurde eine Erhebung zu Auswirkungen der Pandemie auf bereits belastete pflegende Angehörige in Deutschland durchgeführt. Methode Im Rahmen einer Evaluationsstudie zu einem gestuften Beratungsansatz für hochbelastete pflegende Angehörige wurden von 165 Pflegenden quantitative und qualitative Daten zum Belastungserleben, zu Ängsten und Wünschen in der Coronapandemie bezüglich der Pflege erhoben. Die Auswertungen erfolgten deskriptiv und mittels qualitativer Inhaltsanalyse. Ergebnisse Von den Angehörigen gaben 26 % starke Ängste an, sich mit SARS-CoV‑2 zu infizieren, 50 % befürchteten, dass die gepflegte Person erkranken könnte. Die Hälfte berichtete deutliche Auswirkungen auf den Pflegealltag (47 %) und nahm eine deutliche Erhöhung der Pflegbelastung (51 %) wahr. Als häufigste negative Auswirkungen auf den Pflegealltag wurden der Ausfall von Pflegedienstleistungen und ein Mangel an Zeit für sich selbst genannt. Dementsprechend wurde am häufigsten der Wunsch nach Unterstützung geäußert. Der Pflegegrad, das Alter der Pflegenden und die vorherige Nutzung des Pflegedienstes erwiesen sich als Prädiktoren für das durch die Pflegenden eingeschätzte Belastungserleben der Erkrankten. Diskussion Die Ergebnisse verdeutlichen die negativen Auswirkungen der Coronapandemie auf die Belastung pflegender Angehöriger eindrücklich. Zur Bewältigung der komplexen Zusatzbelastungen benötigen Angehörige Angebote, die zu deren Teilhabechancen sowie zur Verbesserung der Versorgung und sozialen Teilhabe der Pflegebedürftigen während der Pandemie beitragen.

Stress concentration factors (SCFs) at weld toes and weld roots as required for the effective notch stress concept (see [1, 2]) are usually computed using finite element analysis (FEA) which requires a certain amount of effort for model generation, the solving process, and postprocessing. Regression functions of many FEAs within given parameter bounds provide the possibility of a fast prediction of SCFs. This paper provides new and accurate regression formulae for the estimation of notch stresses at idealized weld geometries on the basis of multiple linear-elastic FEAs for the transverse stiffener (non-load carrying T-joint) under tension and bending of the load carrying slab. Regression of sampled finite element results has been performed using (a) second-order polynomial regression with coupling terms (PRC) and (b) artificial neural networks (ANN). The presented formulae are compared with several existing estimations of stress concentration factors. The new methods appear to show a higher quality of prognosis as well as apply to significant larger ranges of the geometrical parameters of the weld joint. The formulae presented here for the transverse stiffener add another welded joint to a series of similar surrogate models presented from Munich University of Applied Sciences in earlier publications and made available for use by the web-based tool SCF-Predictor.

ZusammenfassungDie periphere arterielle Verschlusskrankheit (PAVK) gilt als Volkskrankheit mit weltweit mehr als 230 Mio. Betroffenen und schlechter Prognose. Durch den systemischen und progressiven Charakter der Atherosklerose sowie den Befall vieler Gefäßbereiche ist neben dem Risiko für gefäßbedingte Amputationen auch die generelle Lebenserwartung deutlich eingeschränkt. Die strikte Ausschöpfung der konservativen Therapie gilt als wichtiges Fundament der komplementären Behandlung, wird aber nicht immer erfolgreich umgesetzt. Neben dem strukturierten Gehtraining, Raucherentwöhnung, Optimierung von Ernährung und Körpergewicht, Blutdrucktherapie sowie Normalisierung von Blutzucker- und Blutfettwerten gilt die optimale Arzneimitteltherapie als zentrales Behandlungsziel. Dieser Artikel soll laienverständliche evidenzbasierte Empfehlungen zur Optimierung des sogenannten Best Medical Treatment in der Behandlung der PAVK geben.

Background Longleaf pine (Pinus palustris Mill.) ecosystems were historically widespread in the North American Coastal Plain and in some southeastern piedmont and montane settings. The naval stores industry, deforestation, and other human activities resulted in an extensive loss (c. 97% loss) of the original woodlands and savannas. Longleaf pine ecosystems are maintained by frequent surface fire which promotes successful regeneration and maintains open canopy conditions and a largely herbaceous understory. Fire regimes (including the frequency and seasonality of fire) likely varied across the entire range of longleaf pine and through time; further research is needed to elucidate this variability. Results We used fire scars in stumps and snags to reconstruct fire history in a piedmont longleaf pine ecosystem in North Carolina. For each tree sampled, we examined multiple cross sections to avoid omission of fire events recorded by smaller fire scars. Our samples revealed evidence of frequent fire (c. 3–4-year fire interval) beginning in the early eighteenth century and extending to the mid-nineteenth century. Fires occurred in the dormant and early earlywood positions of annual rings and were likely human ignited. Conclusions To our knowledge, this is the first tree-ring-based fire history in longleaf pine of the piedmont. As such, it offers a rare glimpse into historical fire activity in a now scarce but important ecological setting. More research is needed to develop additional fire chronologies in the piedmont region, including for longer periods of time and for larger spatial areas.

In diesem Beitrag werden die starken Empfehlungen (Grad A) der AWMF-Leilinien zum Thema „Nationale Versorgungsleitlinie Typ-2-Diabetes: Praventions- und Behandlungsstrategien fur Fuskomplikationen (Version 2.8, Februar 2010)“ fur die Bereiche weiterfuhrende Diagnostik, therapeutische Masnahmen und Amputation zusammengefasst dargestellt und diskutiert. Einschrankend muss erwahnt werden, dass die Gultigkeit der Leitlinien abgelaufen ist. Eine aktuelle Fassung lag bis zur Entstehung dieses Beitrags noch nicht vor, sodass sich die Autoren dieses Artikels an der letzten verfugbaren Fassung orientierten und zusatzlich Empfehlungen der aktuellen ESVS-Leitlinien CLTI berucksichtigten. Die Vergabe der Empfehlungsgrade erfolgte durch ein formales Konsensusverfahren der beteiligten Leitlinienautoren. Auf die Empfehlungen Grad B und Grad 0 wird in diesem Artikel aufgrund des geringen Empfehlungsgrads nicht eingegangen.