Fostering Students’ Measurement Estimation Skills in a Digital Teaching-Learning Environment: A Class-Wise Randomized Controlled Trial in Grade 5

Students’ measurement estimation skills require benchmark knowledge (about measures of known objects) and estimation strategies (ways to compare with benchmarks). While students’ estimation skills have been assessed and unpacked in several empirical studies (for length and area but less for mass), approaches for fostering them have hardly been empirically studied. We present the instructional design of a digital teaching-learning environment designed to foster fifth graders’ estimation skills for mass measures and empirical evidence for its efficacy. The teaching-learning environment encompassed two 45-minute sessions and drew upon the design principles of cognitive engagement with worked examples, enhanced communication, and scaffolding. A class-wise randomized controlled trial was conducted in 14 classes (involving n = 310 students) with three treatment groups, and two intervention groups worked on estimation strategies in the teaching-learning environment. Both intervention groups significantly outperformed the control group in the post test. The intervention group with highly structured scaffolds only tended to explain the strategies slightly better than the intervention group with regular scaffolds, albeit not significantly. The findings show that estimation skills can be effectively fostered, with a modest indication that highly structured scaffolds might hold promise for longer interventions to enhance students’ discourse practices

Underwater Coherent Optical Wireless Communications with Electronic Beam Steering and Turbulence Compensation Using Adaptive Optics and Aperture Averaging

A novel approach to underwater optical wireless coherent communications using liquid crystal spatial light modulators (LC-SLMs) and an aperture averaging lens, in combination with optical phased-array (OPA) antennas, is presented. A comprehensive channel model that includes a wide range of underwater properties, including absorption, scattering, and turbulence effects, is employed to simulate the underwater optical wireless communication (UOWC) system in a realistic manner. The proposed system concept utilizes aperture averaging and adaptive optics techniques to mitigate the degrading effects of turbulence. Additionally, OPA antennas are integrated into the system to provide electronic beam steering capabilities, facilitating precise pointing, acquisition, and tracking (PAT) between mobile underwater vehicles. This integration enables high-speed and reliable communication links by maintaining optimal alignment. The numerical results show that under strong turbulence, our combined turbulence-compensation approach (LC-SLM plus aperture averaging) can extend the communication range by approximately threefold compared to a baseline system without compensation. For instance, at a soft-decision FEC threshold of 1.25×10−2, the maximum achievable link distance increases from around 10m to over 30m. Moreover, the scintillation index is reduced by more than 90%, and the bit error rate (BER) improves

Synthese von orthogonal photoschaltbaren Azobenzol-Glycoclustern zur Untersuchung des Einflusses der Ligand-Orientierung im Kontext bakterieller Adhäsion

Numerous biological processes, such as the adhesion of bacteria to the highly glycosylated cell surface, the glycocalyx, are governed by carbohydrate-protein (lectin) interactions. Understanding such processes requires the consideration of effects such as multivalency, heteromultivalency as well as the density and relative spatial orientation of the ligands. Azobenzene glycoconjugates have proven to be effective molecular tools to control the orientation of carbohydrates by light-induced isomerization of the azo group and study the influence of ligand orientation, e.g. in carbohydrate-specific bacterial adhesion. In this work, the first orthogonally photoswitchable heterobivalent azobenzene glycocluster was synthesized, its photochromic properties and thermal relaxation kinetics were studied in detail, and the ligand orientation of the addressable predominating isomers (EE, EZ, and ZZ) was analyzed. The combination of an electron-rich unsubstituted and an electron-poor tetra-ortho-fluorinated azobenzene derivative enables orthogonal photoswitching of the antennas. This allows the 3D orientation of the terminal glycoligands (Glc/Man) to be changed as required. This heterobivalent Glc/Man glycocluster was used as a molecular tool to address questions regarding the influence of ligand orientation on carbohydrate-lectin interactions. Besides the Glc/Man glycocluster a homobivalent Man/Man glycocluster and three photosensitive glycoconjugates, representing the antennas of the two glycoclusters, were tested in bacterial adhesion inhibition assays. The results contribute to a deeper understanding of (hetero-) multivalence effects and the influence of ligand orientation on carbohydrate-lectin interactions. They also extend the young field of optoglycomics, which uses photosensitive glycoconjugates to elucidate carbohydrate recognition in greater detail

Untersuchungen zum klinischen Stellenwert von Weichteilsarkomkonfigurationen in der Magnetresonanztomografie

Weichteilsarkome sind seltene, aggressive Tumoren mit hoher Metastasierungs- und Rezidivneigung. Die Bildgebung erfolgt meist mittels MRT mit gadoliniumhaltigem Kontrastmittel, das jedoch nebenwirkungsreich ist. Diese Studie untersuchte Risikofaktoren für Metastasen und Rezidive sowie die Möglichkeit, den Einsatz von Kontrastmittel zu reduzieren. Dafür wurden die Charakteristika von 285 Weichteilsarkome in Bezug auf das Auftreten von Metastasen und Rezidiven untersucht. Zudem wurde geprüft, ob die Tumorkonfiguration eine Beurteilung ohne Kontrastmittel ermöglicht. Als signifikante Risikofaktoren für die Metastasierung erwiesen sich Leiomyosarkome (p=0,002), hoher Tumorgrad (p=0,001; RR=6,2 bzw. p=0,004; RR=7,3), multilobulierte Tumorkonfiguration (p=0,033; RR=3,2), infiltratives Wachstum (p=0,029; RR=3,7), R0-Resektion (p=0,008) und Rezidive (p<0,001; RR=5,5). Diese Ergebnisse bestätigen weitgehend die bisherige Forschung, wobei die Tumorkonfiguration als bislang wenig beachteter Faktor neu in den Fokus rückt. Bezüglich der Rezidive waren adulte Fibrosarkome (p<0,001) sowie Tumore in Axilla/Schulter/Oberarm (p=0,029) als Risikofaktoren relevant. Einige bekannte Risikofaktoren konnten nicht bestätigt werden, was auf die begrenzte Zahl von 50 Rezidiven hindeutet. Ein weiteres wichtiges Ergebnis ist, dass bei multilobulierten Tumoren die nativen MRT-Bilder bereits ausreichen, um Tumorgrenzen und Infiltration sicher zu beurteilen (p<0,001), wodurch auf Kontrastmittel verzichtet werden kann, was Nebenwirkungen reduziert und die Patientensicherheit erhöht. Diese Erkenntnis ist jedoch nur begrenzt verallgemeinerbar, da sie auf der Analyse von 62 primären Weichteilsarkomen beruht. Zukünftige Studien sollten größere, multizentrische Patientenkollektive einbeziehen, um die Aussagekraft der Ergebnisse zu erhöhen und ihre klinische Relevanz weiter zu bestätigen

Unraveling the Stereoisomer Configurations of 1,1’‐bis(tert‐butylphosphino)Ferrocene in the Gas Phase

The molecular structure of a ferrocene derivative with adjacent centers of chirality, 1,1'-bis(tert-butylphosphino)ferrocene, has been examined in the gas phase using broadband microwave spectroscopy under the isolated and cold conditions of a supersonic jet. The diastereomers of 1,1'-bis(tert-butylphosphino)ferrocene can adopt homo- and hetero-chiral configurations, owing to the P-chiral substituents on the cyclopentadienyl rings. Moreover, the internal ring rotation of each diastereomer gives rise to four conformers with eclipsed ring arrangements, where the two tert-butylphosphino groups were separated by dihedral angles of approximately 72°, 144°, 216°, and 288° with respect to the two ring centers. The interconversion barriers between the conformations are below 2 kJ/mol, whereas the pyramidal inversion of the tert-butylphosphino groups is hindered by more than 140 kJ/mol, calculated at the B3LYP-D3(BJ)/def2-QZVP level of theory. In the experimental microwave spectrum, we unambiguously identified the two global-minimum diastereomers with 72° conformations. The absence of other conformers can be attributed to the relaxation dynamics in the supersonic jet, which transfers the high-energy conformers to the respective global-minimum geometries. Additionally, we discovered that London dispersion interactions between the two tert-butylphosphino groups play a crucial role in stabilizing the structures of this ferrocene complex

A Previously Unknown Building Structure in Ancient Olympia (Western Peloponnese, Greece) Revealed by Geoarchaeological Investigations and Its Interpretation as a Possible Harbor

The ancient site of Olympia is located on the northern fringe of the Basin of Makrisia at the confluence of the Kladeos and Alpheios rivers (western Peloponnese, Greece) and was used as a venue for the Panhellenic Games from Archaic times until the 4th century AD. Geophysical prospection (frequency domain electromagnetic induction and electrical resistivity tomography) was carried out as a basis for detailed geoarchaeological investigations. In doing so, we identified a previously unknown building structure adjacent to the Altis, the inner part of the sanctuary at Olympia. Situated south of the Southwest Thermae, this structure measures at least 100 m (WSW-ENE) by 80 m (NNW-SSE). Its external orientation is in line with the orientation of the Southwest Thermae and the Leonidaion. We retrieved sediment cores from 17 different locations in combination with high-resolution direct push sensing from inside the newly found structure. All cores revealed distinct units of organic-rich limnic sediments dominated by clay and fine silt. Geochemical and micropaleontological analyses of selected sediment samples indicate highly eutrophic conditions, as evidenced by elevated phosphorous concentrations and the dominance of the ostracod species Cyprideis torosa, which is able to live under low-oxygen conditions. Moreover, molecular biomarker analyses show a significant input of lipid fecal markers, implying strong anthropogenic pollution. Further, the limnic sediments include numerous charcoal remains and abundant diagnostic artifacts such as ceramic fragments and building material. Radiocarbon dating documents that these limnic conditions persisted within the building structure from at least the 5th century BC to the 6th century AD. The identified building structure lies in the immediate proximity to the Lake of Olympia, which was recently found to have existed from the mid-Holocene to the Medieval period. Its characteristic filling with fine-grained sediments and multiple indications for a strongly polluted and heavily used standing water environment let us hypothesize that it was possibly used as a harbor installation. A harbor at ancient Olympia could have been used to reach the sanctuary by boat and to transport goods of all kinds

Waterlogging Does Not Have a Lasting Impact on Yield Performance and Micronutrient Status of Oat (Avena sativa)

Waterlogging increasingly threatens global crop production, particularly affecting major crops like wheat, barley, and maize at all growth stages. Although research on oat tolerance to waterlogging is limited, there is evidence that oat may be a suitable alternative crop due to its resilience and ability to maintain yields despite nutrient imbalances caused by waterlogging. However, it remains uncertain how oat responds to changes in soil micronutrient availability during periods of waterlogging. Therefore, this study aims to investigate whether (1) micronutrient toxicities or deficiencies are induced during waterlogging, (2) the timing of the flooding event is relevant for the expression of a possible nutrient imbalance, and (3) micronutrient toxicities/deficiencies affect yield performance. In order not to exclude possible varietal differences, three oat varieties were grown in large-scale containers and exposed to 14 days of waterlogging at either BBCH 31 or BBCH 51. Although early but not late waterlogging was effective in reducing dry weights, especially in white oat, yield performance, as reflected by the harvest index, was not affected at all. While early waterlogging increased Mn and Fe concentrations in all oat varieties, they were well below toxic level. In contrast, Cu concentrations in white oat dropped below the deficiency threshold levels. Zinc status, however, remained completely unaffected in all oat varieties. [...] It can therefore be assumed that at least the oat varieties tested have a high regeneration potential and also show a high tolerance to transient micronutrient imbalances

Werkzeuge, Techniken und ihre Kränkungen des Menschen: Versuch einer historischen Rekonstruktion von Schreib- und Denkwerkzeugen vor dem Hintergrund des aktuellen Diskurses um künstliche Intelligenzen

Menschen benutzen seit ihrer Artentstehung Werkzeuge und Techniken, um damit ihre physiologischen sowie ihre kognitiven Defizite zu kompensieren. Auffällig dabei ist, dass der Mensch die jeweiligen Werkzeuge ganz unterschiedlich bewertet. Während Menschen gegenüber Werkzeugen zur Unterstützung ihrer physiologischen Fähigkeiten überwiegend wohlwollend und aufgeschlossen sind, stehen sie Denkwerkzeugen zumeist sehr kritisch gegenüber. Diese kritische Haltung zu verstehen, ist Ziel des vorliegenden Beitrags. Dafür werden zunächst ausgewählte und bedeutsame Meilensteine in der Entwicklung von Denkwerkzeugen, insbesondere unter der exemplarischen Fokussierung von Schreibwerkzeugen, historisch rekonstruiert. Angefangen mit der Entwicklung der Schrift sowie dem Übergang von einer mündlichen in eine schriftliche Kultur, über den modernen Buchdruck, die Erfindung von Taschenrechnern und Computern sowie die Etablierung des Internets und der damit verbundenen Notwendigkeit von Suchmaschinen hin zu aktuellen Entwicklungen und Diskussionen um künstliche Intelligenzen analysiert der Beitrag insbesondere die kritischen Reaktionen auf diese Innovationen. Dabei zeigt sich, dass die Grundstruktur der ablehnend-kritischen Argumentation – eine Verkümmerung der menschlichen Denkfähigkeit – sowie die mit solchen Entwicklungen einhergehenden Ängste und Befürchtungen in ihrem Kern seit Jahrtausenden stabil sind. Um diese Haltung zu verstehen, entwirft der Beitrag eine Deutung, die die Entwicklung von Denkwerkzeugen als kollektive narzisstische Kränkung beschreibt, durch die der Kern menschlichen Selbstverständnisses scheinbar infrage gestellt wird und dadurch diese aversive Haltung hervorbringt.Since the emergence of their species, humans have been using tools and techniques to compensate for their physiological and cognitive deficits. It is noteworthy that humans evaluate these tools very differently. While they are predominantly benevolent and open-minded towards tools that support their physiological abilities, they are often very critical of cognitive tools. Understanding this critical attitude is the aim of this article. For this purpose, selected and significant milestones in the development of cognitive tools, especially with an exemplary focus on writing tools, are historically reconstructed. Starting with the development of writing and the transition from an oral to a written culture, through modern book printing, the invention of calculators and computers, and the establishment of the internet and the associated necessity of search engines, to current developments and discussions about artificial intelligences, the article particularly analyzes the critical reactions to these innovations. It becomes apparent that the basic structure of the rejecting-critical argumentation – a withering of human thinking ability – as well as the fears and concerns associated with such developments have been stable at their core for millennia. To understand this attitude, the article proposes an interpretation that describes the development of cognitive tools as a collective narcissistic injury, which seemingly challenges the core of human self-understanding and thus evokes this aversive attitude

Enhanced extreme sea level information for flood risk assessments along the German Baltic coast

Accurate assessments of flood risk are vital for efficient adaptation to extreme sea level (ESL) induced coastal floods. A major source of uncer- tainty surrounding coastal flood risk are those associated with the estima- tion of ESLs and their probabilities. Given limited sea level observations, uncertainty is an inherent feature of ESL estimation — leading to misallo- cated resources, higher adaptation costs, reduced flood risk mitigation, or even counterproductive outcomes if ignored. Nevertheless, statistical and numerical techniques can enhance available sea level information, adding greater value to flood risk assessments and enabling more efficient adapta- tion planning. This dissertation explores a number of techniques to provide enhanced ESL information for coastal flood risk along the German Baltic Sea coast. Specifically, this thesis (1) models ESL hydrographs, simulating not only the peak water level of extreme events but also their temporal evolution, (2) incorporates historical information into the analysis of ESLs to improve estimates of ESLs, and (3) demonstrates how these enhanced in- formation can be used to perform probabilistic flood modelling, providing a comprehensive assessment of flood exposure

Therapiepräferenzen in der Adjuvanz des malignen Melanoms: eine qualitative Analyse

Die adjuvante Behandlung des malignen Melanoms hat sich im letzten Jahrzehnt deutlich weiterentwickelt, insbesondere durch Immuncheckpointinhibitoren und zielgerichtete Substanzen. Sie erfolgt nach operativer Resektion und ist angezeigt, wenn eine Metastasierung nicht ausgeschlossen werden kann. Sie verlängert das Überleben und senkt das Rückfallrisiko, birgt jedoch potenziell schwere Nebenwirkungen. Daher ist eine sorgfältige Abwägung von Chancen und Risiken erforderlich, unter Einbezug medizinischer Faktoren und individueller Präferenzen. Voraussetzung dafür ist eine vertrauensvolle Arzt-Patienten-Kommunikation. Im Rahmen der GERMELATOX-Studie wurden Patientenpräferenzen zur adjuvanten Therapie qualitativ untersucht. Aufbauend auf einer quantitativen Befragung wurden 17 semistrukturierte Interviews geführt und nach Mayring ausgewertet. Die Ergebnisse lassen sich in vier thematische Cluster gliedern: Therapieform und -ablauf, Lebensgestaltung, Gefühle und Empfinden sowie methodisches Vorgehen. Die Erfolgsaussicht war der wichtigste Entscheidungsfaktor. Rezidivfreies Überleben wurde oft dem Gesamtüberleben gleichgesetzt. Es bestanden klare Präferenzen hinsichtlich oraler oder intravenöser Gabe. Mit zunehmenden Nebenwirkungen sank die empfundene Erträglichkeit, während Erwartungen an die Wirksamkeit stiegen. Ängste vor Organschäden oder Rückfällen prägten das Erleben stark. Der Wunsch nach Selbstbestimmung und hoher Lebensqualität war zentral. Ältere Patienten waren zurückhaltender, besonders bei geringer Erfolgserwartung. Frühere Erfahrungen mit Krebstherapien beeinflussten die Einstellung ebenfalls. Die Ergebnisse zeigen eine hohe, aber abwägende Therapiebereitschaft. Die Einbindung individueller Präferenzen ist entscheidend für eine passende, vertrauensvolle Therapieentscheidung