Remote sensing of coastal erosion and thaw slump activities effected by heavy precipitation in West Alaska

In this study the dynamics of retrogressive thaw slumps (RTS), which are main permafrost thawing features along the eroding coasts of the Arctic region, were investigated by using MACS airborne stereo ortho imagery of the 2021 Perma-X flight campaign in West Alaska. The attempt was a remote sensing change detection done by using digital terrain models for structure from motion photogrammetry. The developed workflow was applied at two study sites at the coast of the Baldwin Peninsula. At the time of the data acquisition in June and July 2021 the area was facing heavy rainfalls, which are assumed to occur more often and intensely due to climate change. The aim was to use the results of the digital terrain model differences for measuring the rainfall erosion and their impact on RTS activity. For processing images photogrammetrically and generating digital elevation models PIX4D was used. Image adjustments and the difference calculations were done with QGIS. Unfortunately the created digital terrain models show a lot of large and small scale failures, which were so severe that a successful DTM differencing was not possible. Mass movement and erosion can be seen at some locations in the DTM, but accurate detecting or measuring of RTS dynamics was not possible with the data and the developed workflow. Therefore the influence of the heavy rainfall event of Summer 2021 remains unclear up to this point

Glossar urbane Praxis

GLOSSAR URBANE PRAXIS Glossar urbane Praxis / Becker, Jochen (Rights reserved) ( -

Super-high-resolution Earth observation datasets of North American permafrost landscapes

While temperatures are increasing on the global scale, the Arctic regions are especially vulnerable to this changing climate and landscapes underlain by permafrost experience increased thaw and degradation. The enhanced warming of organic-rich frozen ground can have severe consequences on infrastructure and ecosystems and is projected to become a highly relevant driver of greenhouse gas fluxes into the atmosphere. Degrading permafrost landscapes occur extensively in vast areas of the North American Arctic, directly affecting communities and ecosystems. To identify and quantify these widespread degradation phenomena over vast areas, we require highest-resolution Earth observation dataset that we collect during aerial imaging campaigns. We here report on observations and first results from three airborne campaigns in 2018, 2019 and 2021. We performed large-scale monitoring of permafrost-affected areas in northern Canada and Alaska, focusing on sites that experienced disturbances in the past or recently. This included sites with vulnerable settlements, coastal erosion, thaw slumping, lake expansion and drainage, ice-wedge degradation and thaw subsidence, fire scars, pingos, methane seeps, and sites affected by beaver activities. All surveys were flown with the Alfred Wegener Institute's Polar-5 and -6 scientific airplanes at 500-1500 m altitude above terrain. The onboard sensor, the Modular Aerial Camera System (MACS), a very-high-resolution multispectral camera developed by the German Aerospace Center, operated in the visible (RGB) and near-infrared (NIR) domain. From the comprehensive collection of multiple TB of gathered data, super-high-resolution (up to 7 cm/px) RGB+NIR image mosaics and stereophotogrammetric digital surface models were derived. By presenting the data and first analyses, we would like to invite the community to discuss best use for maximized benefit of the data, in order to substantially contribute to our understanding of permafrost thaw dynamics

Spin dynamics in semiconductors

This article reviews the current status of spin dynamics in semiconductors which has achieved a lot of progress in the past years due to the fast growing field of semiconductor spintronics. The primary focus is the theoretical and experimental developments of spin relaxation and dephasing in both spin precession in time domain and spin diffusion and transport in spacial domain. A fully microscopic many-body investigation on spin dynamics based on the kinetic spin Bloch equation approach is reviewed comprehensively.Comment: a review article with 193 pages and 1103 references. To be published in Physics Reports

Size and surface charge of gold nanoparticles determine absorption across intestinal barriers and accumulation in secondary target organs after oral administration

It is of urgent need to identify the exact physico-chemical characteristics which allow maximum uptake and accumulation in secondary target organs of nanoparticulate drug delivery systems after oral ingestion. We administered radiolabelled gold nanoparticles in different sizes (1.4-200 nm) with negative surface charge and 2.8 nm nanoparticles with opposite surface charges by intra-oesophageal instillation into healthy adult female rats. The quantitative amount of the particles in organs, tissues and excrements was measured after 24 h by gamma-spectroscopy. The highest accumulation in secondary organs was mostly found for 1.4 nm particles; the negatively charged particles were accumulated mostly more than positively charged particles. Importantly, 18 nm particles show a higher accumulation in brain and heart compared to other sized particles. No general rule accumulation can be made so far. Therefore, specialized drug delivery systems via the oral route have to be individually designed, depending on the respective target organ

A Stratified Transcriptomics Analysis of Polygenic Fat and Lean Mouse Adipose Tissues Identifies Novel Candidate Obesity Genes

Obesity and metabolic syndrome results from a complex interaction between genetic and environmetal factors. In addition to brain-regulated processes, recent genome wide association studies have indicated that genes highly expressed in adipose tissue affect the distribution and function of fat and thus contribute to obesity. Using a stratified transcriptome gene enrichment approach we attempted to identify adipose tissue-specific obesity genes in the unique polygenic fat (F) mouse strain generated by selective breeding over 60 generations for divergent adiposity from a comparator lean (L) strain. To enrich for adipose tissue obesity genes a ˝snap-shot˝ pooled-sample transcriptome comparison of key fat depots and non adipose tissue (muscle, liver, kidney) was performed. Known obesity quantitative trait loci (QTL) information for the model allowed us to further filter genes for increased likelihood of being causal or secondary for obesity. This successfully identified several genes previously linked to obesity (C1qr1, and Np3r) as positional QTL candidate genes elevated specifically in F line adipose tissue.A number of novel obesity candidate genes were also identified (Thbs1, Ppp1rd, Tmepai, Trp53inp2, Ttc7b, Tuba1a, Fgf13, Fmr) that have inferred rolesin fat cell function. Quantitative microarray analysis was then applied to the most phenotypically divergent adipose depot after exaggerating F and L strain differences with chronic high fat feeding which revealed a dictinct gene expression profile of line, fat depot and diet-responsive inflammatory, angiogenic and metabolic pathaways. Selected candidate genes Npr3 and Thbs1, as well as Gys2, a non-QTL gene that otherwise passed our enrichment criteria were characterised, revealing novel functional effects consistent with a contribution to obesity. A focussed candidate gene enrichment strategy in the unique F and L model has identified novel adipose tissue-enriched genes contributing to obesity

„Die Spirale muss nach oben gehen“: Ein Interview mit Mitgliedern der Berliner Initiative Urbane Praxis

Künstler*innen, Stadtaktivist*innen, Akteur*innen aus Kultur, Architektur und Soziokultur haben sich 2020 in Berlin auf Initiative des Rates für die Künste zu einem Verbund zusammengeschlossen und erproben in Stadtlaboren und Campusprojekten diverse die Peripherie einbeziehende Kooperations-und Gestaltungsformen stadträumlicher Transformation. Bis dato fanden Raumexperimente, Aktions-und Thinktank-Formate sowie Symposien und Konferenzen statt. Ein für internationale Beiträge offenes Glossar wurde publiziert und elf Thesen zur Untermauerung der Notwendigkeit struktureller Veränderungen erstellt. Gegründet wurde der Verein für Urbane Praxis. Anna Schäffler, Jochen Becker und Simon Sheikh zählen zu den Initiator*innen. Im Gespräch stellen sie die Arbeit und ihre Projekte vor

„Die Spirale muss nach oben gehen“: Ein Interview mit Mitgliedern der Berliner Initiative Urbane Praxis

Künstler*innen, Stadtaktivist*innen, Akteur*innen aus Kultur, Architektur und Soziokultur haben sich 2020 in Berlin auf Initiative des Rates für die Künste zu einem Verbund zusammengeschlossen und erproben in Stadtlaboren und Campusprojekten diverse die Peripherie einbeziehende Kooperations-und Gestaltungsformen stadträumlicher Transformation. Bis dato fanden Raumexperimente, Aktions-und Thinktank-Formate sowie Symposien und Konferenzen statt. Ein für internationale Beiträge offenes Glossar wurde publiziert und elf Thesen zur Untermauerung der Notwendigkeit struktureller Veränderungen erstellt. Gegründet wurde der Verein für Urbane Praxis. Anna Schäffler, Jochen Becker und Simon Sheikh zählen zu den Initiator*innen. Im Gespräch stellen sie die Arbeit und ihre Projekte vor

Particle size-dependent and surface charge-dependent biodistribution of gold nanoparticles after intravenous administration

Gold nanoparticles (GNP) provide many opportunities in imaging, diagnostics, and therapies of nanomedicine. Hence, their biokinetics in the body are prerequisites for specific tailoring of nanomedicinal applications and for a comprehensive risk assessment. We administered (198)Au-radio-labelled monodisperse, negatively charged GNP of five different sizes (1.4, 5, 18, 80, and 200 nm) and 2.8 nm GNP with opposite surface charges by intravenous injection into rats. After 24h, the biodistribution of the GNP was quantitatively measured by gamma-spectrometry. The size and surface charge of GNP strongly determine the biodistribution. Most GNP accumulated in the liver increased from 50% of 1.4 nm GNP to >99% of 200 nm GNP. In contrast, there was little size-dependent accumulation of 18-200 nm GNP in most other organs. However, for GNP between 1.4 nm and 5 nm, the accumulation increased sharply with decreasing size; i.e. a linear increase with the volumetric specific surface area. The differently charged 2.8 nm GNP led to significantly different accumulations in several organs. We conclude that the alterations of accumulation in the various organs and tissues, depending on GNP size and surface charge, are mediated by dynamic protein binding and exchange. A better understanding of these mechanisms will improve drug delivery and dose estimates used in risk assessment

Super-high-resolution Earth observation datasets of North American permafrost landscapes

While temperatures are increasing on the global scale, the Arctic regions are especially vulnerable to this changing climate and landscapes underlain by permafrost experience increased thaw and degradation. The enhanced warming of organic-rich frozen ground can have severe consequences on infrastructure and ecosystems and is projected to become a highly relevant driver of greenhouse gas fluxes into the atmosphere. Degrading permafrost landscapes occur extensively in vast areas of the North American Arctic, directly affecting communities and ecosystems. To identify and quantify these widespread degradation phenomena over vast areas, we require highest-resolution Earth observation dataset that we collect during aerial imaging campaigns. We here report on observations and first results from three airborne campaigns in 2018, 2019 and 2021. We performed large-scale monitoring of permafrost-affected areas in northern Canada and Alaska, focusing on sites that experienced disturbances in the past or recently. This included sites with vulnerable settlements, coastal erosion, thaw slumping, lake expansion and drainage, ice-wedge degradation and thaw subsidence, fire scars, pingos, methane seeps, and sites affected by beaver activities. All surveys were flown with the Alfred Wegener Institute's Polar-5 and -6 scientific airplanes at 500-1500 m altitude above terrain. The onboard sensor, the Modular Aerial Camera System (MACS), a very-high-resolution multispectral camera developed by the German Aerospace Center, operated in the visible (RGB) and near-infrared (NIR) domain. From the comprehensive collection of multiple TB of gathered data, super-high-resolution (up to 7 cm/px) RGB+NIR image mosaics and stereophotogrammetric digital surface models were derived. By presenting the data and first analyses, we would like to invite the community to discuss best use for maximized benefit of the data, in order to substantially contribute to our understanding of permafrost thaw dynamics