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Kohlenstoffzentrierte Reaktivität von Carbodiphosphoran Liganden ermöglicht nicht-unschuldige Redoxaktivität, Ligand-Ligand-Kooperation und Duale-Bindungsaktivierungen
Full text linkKoordinierte Liganden sind in der Regel nicht mehr nukleophil und nicht in die Redox-Prozesse von Metallkomplexen involviert. In diesem Manuskript berichten wir über das Vorliegen beider Eigenschaften in koordinierten Carbodiphosphoranen (CDP), was zu bisher unbekannten, kohlenstoffzentrierten Reaktivitätsmustern führt: Ein CDP-basierender Rhodium-Pinzetten-Komplex ermöglicht dabei die Spaltung von zwei C−Cl-Bindungen in geminalen Dichloriden durch zwei aufeinanderfolgende, SN2-artige oxidative Additionsschritte, was zur Bildung eines stabilisierten Carben-Fragments führt. In Anwesenheit eines geeigneten Reduktionsmittels kann das Carben-Fragment in einer katalytischen Reaktion in Olefine oder Hydrodehalogenierungsprodukte überführt werden. Die entwickelte Methode kann auch zur Umwandlung von Fluorchlorkohlenwasserstoffen (FCKW) wie CH2ClF in Fluormethan und Methan verwendet werden. Der stark nucleophile Charakter der koordinierten CDPs spiegelt sich auch in dem geringen Oxidationspotenzial wider, was die Bildung von Radikalen begünstigt und zu einem einzigartigen kationischen Kohlenstoff-zentrierten radikalischen CDP-Liganden führt. Dieses kohlenstoffzentrierte Radikal ist in der Lage Wasserstoff durch das kooperative Zusammenspiel mit einem weiteren Liganden zu aktivieren
The ground-nesting bee Anthophora plumipes as a model species for assessing effects of soil-mediated pesticide exposure
Full text linkThough many wild bee species nest in the ground, little is known of their potential exposure to pesticide residues in soil, or the effects of such exposure. Here, we introduce Anthophora plumipes as a potential model ground-nesting solitary bee species for controlled exposure to pesticides through soil. Bees from a naturally occurring population were allowed to nest in loam blocks containing varying concentrations of the neonicotinoid imidacloprid. Measured residues of imidacloprid in brood provisions and in bee bodies remained at < 0.01% of the concentration in surrounding soil, suggesting limited migration of contaminants from soil to brood. Furthermore, imidacloprid contamination had no marked effect on the number, survival, body size or rate of parasitism of offspring at the tested concentrations (≤ 10 mg/kg). This species native to Eurasia and North Africa may be a suitable model for further research on the ecotoxicology of ground-nesting solitary bee species
Female agency and colonial repression : memory and archives in Tunisia
Full text linkKeywords: Resistance, women, public history, agencyKeywords: Widerstand, Frauen, öffentliche Geschichte, Agenc
Laterale Trajektorienprädiktion für Motorräder
Full text linkMotorradfahrer gehören zu den vulnerablen Verkehrsteilnehmern und erfahren zu einem
vielfach höheren Risiko Unfälle mit schweren oder tödlichen Verletzungen. Es werden deshalb
aktive Sicherheitssysteme für Motorräder entwickelt, um das Auftreten von Unfällen zu
vermeiden. Damit zukünftige Systeme in zusätzlichen Fahrsituationen warnen oder rechtzeitig
eingreifen können, benötigen diese eine Prädiktion der Fahrt, im Allgemeinen ausgedrückt
durch die zukünftige Positionstrajektorie. Bestehende physikalische Modelle der Trajektorien-
prädiktion gehen nicht auf die Eigenheiten des Zweirads ein und erreichen besonders in
Kurvenfahrt Vorausschauzeiten von nur 1 s bis maximal 2 s.
Die besondere Querdynamik des Zweirads motiviert die Erforschung von motorradspezifischen
Modellen der Trajektorienprädiktion. Ein Versuchsmotorrad wird ausgestattet, um bisher nicht
verwendete Messgrößen der Lenk-Zustandsgrößen, der Lenkmoment-Fahrereingabe und des
Fahrerverhaltens in Oberkörperposition und Kopfdrehung zu erfassen. Nach der Untersuchung
des querdynamischen Übertragungs- und Fahrerverhaltens anhand von Fahrversuchen wird ein
geringes Potenzial motorradspezifischer physikalischer Prädiktionsmodelle festgestellt.
Stattdessen wird ein manöverbasierter Prädiktionsansatz verfolgt, welcher mittels der Methode
des maschinellen Lernens Informationen zur Fahrerabsicht aus der Zeithistorie von Fahr-
dynamiksignalen und der neuen Signale der Lenkung und des Fahrerverhaltens interpretiert.
Basierend auf einem 74 h und 21 Fahrer umfassenden, selbst erhobenen Fahrdatensatz wird ein
auf LSTM-Zellen (Long Short-Term Memory) basierendes neuronales Netz entwickelt. Indem
dieses eine Rollwinkeltrajektorie über einen 4 s langen Prädiktionshorizont vorhersagt, wird
gezielt nur die laterale Komponente der Trajektorienprädiktion adressiert. Die Transformation
in eine Positionstrajektorie erfolgt unter der Annahme konstanter Geschwindigkeit.
Die manöverbasierte laterale Trajektorienprädiktion erreicht in 98,6 % der Testsituationen
mindestens 2 s Vorausschauzeit. Gegenüber der Standard-Prädiktion konstanter Kurvenfahrt
wird die Anzahl der Situationen mit weniger als 2 s Vorausschau um 89 % reduziert. Die
Bedeutung der neuartigen Messgrößen der Lenkung und des Fahrerverhaltens für die
Prädiktionsgüte wird in Ablationsstudien untersucht. Wenn sie nicht zur Verfügung stehen,
steigt der laterale Positionsfehler um 11,6 %. Rund die Hälfte des positiven Effekts geht vom
Lenkmomentsignal aus, welches die Prädiktion in der ersten Sekunde verbessert. Bis zur
Prädiktionszeit von 1,5 s und 3 s haben die Oberkörperposition und der Kopfdrehwinkel
positiven Einfluss. Die Forschung an motorradspezifischer Trajektorienprädiktion führt zu
neuen Erkenntnissen bzgl. Fahrereingaben und -verhalten in Kurvenfahrt und schafft die
Grundlagen für die Entwicklung zukünftiger Assistenz- und Sicherheitssysteme im Motorrad.Motorcycle riders belong to the group of vulnerable road users as they are in high risk of heavy
injury or fatality in case of accidents. The development of active safety systems for motorcycles
aims to prevent these from occurring. Such systems need a predictive element, generally a
trajectory prediction, to warn or intervene properly in critical riding situations. State-of-the-art
physical trajectory prediction models do not account for the unique characteristics of two-
wheelers and thus achieve look-ahead times of only 1 to max. 2 seconds, especially in
cornering.
The special lateral dynamics of two-wheelers motivates research on motorcycle-specific
algorithms for trajectory prediction. A test motorcycle is being equipped to measure steering
state variables, the steering torque rider input, and signals of rider behaviour in upper body
position and head rotation – all these signals are not used in existing systems. After investigating
the motorcycles’ transfer behaviour and rider behaviour based on specific lateral dynamic test
manoeuvres, motorcycle-specific physical models for trajectory prediction are assessed low
potential. Instead, a manoeuvre-based prediction approach is pursued, that uses machine
learning methods to interpret information on rider intention from the time history of riding
dynamic as well as the new steering and rider behaviour signals. A neural network comprising
LSTM cells (long short-term memory) is developed based on a self-collected data set containing
74 hours of open road riding and 21 riders. It purposely addresses only the lateral component
of trajectory prediction by forecasting a roll angle trajectory over a prediction horizon of 4
seconds. This is transformed into a trajectory of future relative positions assuming constant
longitudinal velocity of the motorcycle.
The manoeuvre-based lateral trajectory prediction achieves at least 2 seconds look-ahead time
in 98.6 % of the test situations. Compared to the standard trajectory prediction that assumes
constant cornering, the number of predictions with less than 2 seconds look-ahead time is
reduced by 89 %. The importance of the new steering and rider behaviour measurements for
the prediction quality is investigated in ablation studies. The lateral position error increases by
11.6 % if all of them are not available. About half of the positive effect comes from the steering
torque signal, that strongly improves the prediction in the first second. The upper body position
improves trajectory prediction up to a prediction time of 1.5 seconds, the head rotation angle
even up to 3 seconds. This research on motorcycle-specific lateral trajectory prediction provides
new insights concerning rider inputs and behaviour in cornering and lays the foundation for the
development of future motorcycle assistance and safety systems
Ein Jahr Open Access Offensive : Erste Bilanz einer fokussierten Transformation an der Hochschule Magdeburg-Stendal
Full text linkDer Artikel präsentiert am Beispiel der Hochschulbibliothek Magdeburg-Stendal, wie eine fokussierte Transformation hin zu Open Access aussehen und gelingen kann. Spezifische Hintergründe und Herausforderungen werden ebenso angesprochen wie praxisorientierte Ansätze und damit zusammenhängende Überlegungen und Entwicklungsschritte
Spatiotemporal dynamics and prevention strategies of cervical cancer incidence in Addis Ababa, Ethiopia : an ecological study
Full text linkObjective: This study analysed the spatial and temporal patterns of cervical cancer incidence in Addis Ababa from 2012 to 2021.
Design: An ecological study was conducted from 1 September to 30 November 2023 to examine the spatiotemporal trends of cervical cancer incidence.
Setting: The research was conducted in Addis Ababa, the capital city of Ethiopia.
Participants: Included were all patients with clinically and/or histopathologically confirmed diagnoses of cervical cancer.
Data analysis: The study employed advanced analytical tools including R programming, Quantum Geographic Information System V.3.36.0, GeoDa V.1.2.2 and System for Automated Geoscientific Analyses GIS V.9.3.2. Techniques such as Bayesian empirical testing with a block weighting matrix for hotspot identification, Global Moran’s I for spatial autocorrelation, nearest neighbour imputation and universal Kriging interpolation were used to manage data gaps. Joinpoint trend analysis and direct age-standardised incidence rate (ASIR) using the Segi’s World standard population was applied to compare trends across subcities. A statistical significance threshold was set at p<0.05.
Results: Between 2012 and 2021, a total of 2435 new cervical cancer cases were recorded in the Addis Ababa City Population-based Cancer Registry, with significant spatial clustering observed in Nifas Silk Lafto, Bole, Kirkos as well as parts of Gulele and Yeka sub cities (z score>1.96) in 2018. The citywide age-standardised incidence rate varied from 19 to 26 cases per 100 000 women-years during 2013 and 2016, respectively. Subcity trends varied significantly, with increases and decreases noted in Akaki Kality and Kolfe Keraniyo over different periods while Bole subcity showed modest increase at 4.2% APC (95% CI: 0.6% to 7.9%; p=0.026).
Conclusion: The study highlights substantial fluctuations in ASIR and significant geographic disparities in cervical cancer throughout Addis Ababa. To address these challenges, the implementation of school-based human papillomavirus vaccination programmes, alongside targeted interventions, active campaigns and sustained surveillance, is critical. These strategies are essential to effectively reduce the cervical cancer burden and improve health outcomes in the community
Lasiodiplodia theobromae disease symptom development in young avocado (Persea americana L.) plants depends on the inoculation method
Full text linkLasiodiplodia theobromae is a pathogenic fungus of more than 500 plant species, including avocado (Persea americana Mill.). The global production volume of avocado exceeded 911,000 metric tons in 2023. Although detailed quantitative surveys of yield losses caused by L. theobromae are not available for most avocado-producing regions, estimates indicate that this pathogen is associated with stem-end rot disease in 30-35% of plots located in the Department of Antioquia in Colombia (Ramírez-Gil et al. Heliyon 7: e05905, 2021), suggesting an enormous economic impact. As yield losses strongly depend on the virulence of isolates, a reliable method for determining their aggressiveness is indispensable for initiating disease control measures. In this study, we compared progression of external and internal necrosis caused by the aggressive L. theobromae isolate LA-VLCA3 inoculated into wounded middle parts of the stem and onto excised apices. Irrespective of the inoculation method, internal progression of necrosis preceded that of external necrosis. Spreading of external and internal necrosis was significantly more severe in plants inoculated at the apex than in mid-stem inoculated plants. We conclude that apex inoculation causes stronger symptoms and is therefore better suited to compare virulence of isolates than mid-stem inoculation
Naturally occurring prenylated flavonoids from African Erythrina plant species
No full textFlavonoids refer to a large class of secondary metabolites with a unique skeleton comprising two aromatic rings linked together by a C3 unit. This class of compounds is largely distributed in plants and rarely occurs in fungi. Some of these compounds are directly bonded to prenyl units. Prenyl groups are C-5 carbon units derived from the mevalonate pathway, are reported to substantially improve the biological activities of diverse classes of secondary metabolites. Prenylated flavonoids display a broad spectrum of biological activities, including antibacterial, antioxidant, anticancer, antidiabetic and antiviral activities. Some flavonoids have already been formulated as either medicines or dietary supplements and are currently used in the management of certain medical conditions. The continuous search for bioactive molecules is a global concern; and encapsulating the contribution of each continent and/or country in terms of available resources should be a priority. This paper aims to methodically summarize the bioactive prenylated flavonoids characterized from plants of the genus Erythrina growing in Africa, as well as their distribution in the genus. Approximately 289 prenylated flavonoids have been isolated and characterized exclusively from plants belonging to the genus Erythrina growing in Africa, covering all the subclasses of flavonoids bearing prenyl group(s), namely, flavanones, flavones, chalcones, isoflavanones, isoflavones, isoflavans, isoflav-3-enes, pterocarpans and pterocarpenes isolated from 1981 to date. This review encompasses the data gathered from 202 peer-reviewed articles and covers the source, isolation, distribution of Erythrina plant species throughout the continent, structure elucidation of prenyl moieties, biological activities as well as the in silico tests where available towards some targets in drug discovery
Assistierter Suizid im deutschen Strafvollzug : grundlegende und vollzugsrechtsspezifische Gedanken anlässlich OLG Hamburg, Beschl. v. 27.8.2024 – 5 Ws 41/24 Vollz und BVerfG, Beschl. vom 31.1.2025 – 2 BvR 1290/24
No full textMLUH-E-191_1, [Accipiter striatus velox (Wilson, A, 1812)], eggshell
No full textInventory No.: MLUH-E-191_1, Object: eggshell, Species: [Accipiter striatus velox (Wilson, A, 1812)], Preservation: complete preservation, Locality_loc.: Atlanta, Locality today: Atlanta, Country: USADate: 13/05/1901, Collection_coll.: M. Schönwetter, published in Handbuch der Oologie, Schönwetter, Max: Vol. I, p. 161, Identification by: M. Schönwetter, Aquisition: 1904, Aquired from: O. Bamberg, ex Collection: ex. Coll. O. Bamber