Wind-induced variability of warm water on the Southern Bellingshausen Sea continental shelf

The Bellingshausen Sea hosts heat transport onto the continental shelf, potentially enhancing ice shelf basal melt. Here we use the GLORYS12V1 1993-2018 reanalysis to identify physical processes that set seasonal and interannual variability of water mass properties in the Eltanin and Latady bays on the southern Bellingshausen Sea continental shelf. Annual means of potential temperature from 300 m to the seabed reveal interannual variability and allow separation into warm and cold regimes. The Amundsen Sea Low is more intense and extends further east during the warm regime than the cold regime. In the warm regime, a wind-induced reduction of sea ice concentration near the coast increases surface heat loss, convection, and formation of cold dense water in winter, associated with a decrease in heat content of the southern Bellingshausen Sea over time and a net northward heat transport. In contrast, in the cold regime, increased sea ice concentration reduces surface heat loss and thus formation of cold, dense water. Combined with an increase in heat content over time and a net southward heat transport, this results in a warming of the southern Bellingshausen Sea. This suggests that variability in the deep water temperature in the southern Bellingshausen Sea is primarily due to local surface heat fluxes above the shelf. The variability of surface heat fluxes is related to the variability of the Amundsen Sea Low and its influence on sea ice extent and local formation of cold, dense water in winter

Angiographic findings and clinical implications of persistent primitive hypoglossal artery

BACKGROUND: The primitive hypoglossal artery (PHA) is a rare vascular anomaly, which belongs to the group of carotid-basilar anastomosis that may occur in adults. CASE PRESENTATION: Herein is presented a case of a patient with a PHA, who had undergone a cerebral angiography due to investigation of subarachnoid hemorrhage. Additionally, the diagnostic alternatives for detection and assessment of PHA and the spectrum of diseases related to its presence are discussed. CONCLUSIONS: The presence of a persistent PHA can be recognized as an incidental finding in a cerebral angiography without any other clinical implication or may be associated with certain clinical entities such as aneurysm formation and atherosclerotic disease

Stirring across the Antarctic Circumpolar Current's southern boundary at the prime meridian, Weddell Sea

At the southern boundary of the Antarctic Circumpolar Current (ACC), relatively warm ACC waters encounter the colder waters surrounding Antarctica. Strong density gradients across the southern boundary indicate the presence of a frontal jet and are thought to modulate the southward heat transport across the front. In this study, the southern boundary in the Weddell Sea sector at the prime meridian is surveyed for the first time in high resolution over 2 months during an austral summer with underwater gliders occupying a transect across the front on five occasions. The five transects show that the frontal structure (i.e. hydrography, velocities and lateral density gradients) varies temporally. The results demonstrate significant, transient (a few weeks) variability of the southern boundary and its frontal jet in location, strength and width. A mesoscale cold-core eddy is identified to disrupt the southern boundary’s frontal structure and strengthen lateral density gradients across the front. The front's barrier properties are assessed using mixing length scales and potential vorticity to establish the cross-frontal exchange of properties between the ACC and the Weddell Gyre. The results show that stronger lateral density gradients caused by the mesoscale eddy strengthen the barrier-like properties of the front through reduced mixing length scales and pronounced gradients of potential vorticity. In contrast, the barrier-like properties of the southern boundary are reduced when no mesoscale eddy is influencing the density gradients across the front. Using satellite altimetry, we further demonstrate that the barrier properties over the past decade have strengthened as a result of increased meridional gradients of absolute dynamic topography and increased frontal jet speeds in comparison to previous decades. Our results emphasise that locally and rapidly changing barrier properties of the southern boundary are important to quantify the cross-frontal exchange, which is particularly relevant in regions where the southern boundary is located near the Antarctic shelf break (e.g. in the West Antarctic sector)

A simple and versatile design concept for fluorophore derivatives with intramolecular photostabilization

Intramolecular photostabilization via triple-state quenching was recently revived as a tool to impart synthetic organic fluorophores with 'self-healing' properties. To date, utilization of such fluorophore derivatives is rare due to their elaborate multi-step synthesis. Here we present a general strategy to covalently link a synthetic organic fluorophore simultaneously to a photostabilizer and biomolecular target via unnatural amino acids. The modular approach uses commercially available starting materials and simple chemical transformations. The resulting photostabilizer-dye conjugates are based on rhodamines, carbopyronines and cyanines with excellent photophysical properties, that is, high photostability and minimal signal fluctuations. Their versatile use is demonstrated by single-step labelling of DNA, antibodies and proteins, as well as applications in single-molecule and super-resolution fluorescence microscopy. We are convinced that the presented scaffolding strategy and the improved characteristics of the conjugates in applications will trigger the broader use of intramolecular photostabilization and help to emerge this approach as a new gold standard

Der historische Pygmalioneffekt der Lehrergenerationen im Bildungswachstum von 1884 bis 1993

Das Bildungssystem wuchs in den letzten 200 Jahren in regelmäßigen Schüben der relativen Bildungsbeteiligung, denen jeweils Stagnationsphasen folgten. Mithilfe einer systematischen Inhaltsanalyse von 2.370 Artikeln der Lehrerverbandspresse für den Zeitraum 1884 bis 1993 konnten wir feststellen, dass Lehrer an höheren Schulen und Volksschullehrer generationsspezifische Diskurse zur Bildungsselektion führen. Mit den langen Wellen des Bildungswachstums wandeln sich die pädagogischen Problemstellungen und damit mehrheitlich die (Vor-) Einstellungen der Lehrergenerationen über die Schülerauslese in spezifischer Art und Weise. Die Deutungsmuster der Generationen verändern sich in der ständigen Auseinandersetzung mit der Umwelt in einem ähnlichen Modus wie bei Einzelpersonen. (DIPF/Orig.)During the last 200 years, the educational system in Germany developed in recurrent spurts of growth in relative enrollment in the educational system, regularly followed, in turn, by phases of stagnation. On the basis of a systematic content-analysis of 2.370 articles published by teacher associations in the period from 1884 to 1993, it could be shown that teachers from secondary schools and elementary schools lead generation-specific discourses on educational selection. With the long waves of educational growth, pedagogical issues change in a specific manner, and with them the majority of the teacher generations´ (possibly biased) attitudes regarding student selection. The generational patterns of interpretation change due to the persistent confrontation with the environment, in a mode similar to that observed with individual persons. (DIPF/Orig.

The life cycle assessment of cellulose pulp from waste cotton via the SaXcellTM process.

Recycling of cotton waste into high value products is a longstanding goal in textile research. The SaXcellTM process provides a chemical recycling route towards virgin fibres. In this study a Life cycle assessment (LCA) is conducted to measure the impact of the chemical recycling of cotton waste on the environment. Pure cotton waste and cotton containing 10 % of polyester are elaborated. The results show that chemical recycling via the SaXcellTM process can have a lower impact on climate change and other impact category than comparable pulping technologies.   doi:10.1088/1757-899X/254/19/19201