Canonical Interacting Quantum Fields on Two-Dimensional De Sitter Space

We present the ${\mathscr P}(\varphi)_2$ model on de Sitter space in the canonical formulation. We discuss the role of the Noether theorem and we provide explicit expressions for the energy-stress tensor of the interacting model.Comment: minor correction

It is not just a ‘trade‐off’: : indications for sink‐ and source‐limitation to vegetative and regenerative growth in an old‐growth beech forest

Summary Controls on tree growth are key issues in plant physiology. The hypothesis of our study was that the interannual variability of wood and fruit production are primarily controlled directly by weather conditions (sink limitation), while carbon assimilation (source limitation) plays a secondary role. We analyzed the interannual variability of weather conditions, gross primary productivity (GPP) and net primary productivity (NPP) of wood and fruits of an old‐growth, unmanaged Fagus sylvatica forest over 14 yr, including six mast years. In a multiple linear regression model, c . 71% of the annual variation in wood‐NPP could be explained by mean air temperature in May, precipitation from April to May (positive influence) and fruit‐NPP (negative influence). GPP of June to July solely explained c . 42% of the variation in wood‐NPP. Fruit‐NPP was positively related to summer precipitation 2 yr before ( R 2 = 0.85), and negatively to precipitation in May ( R 2 = 0.83) in the fruit years. GPP had no influence on fruit‐NPP. Our results suggest a complex system of sink and source limitations to tree growth driven by weather conditions and going beyond a simple carbon‐mediated ‘trade‐off’ between regenerative and vegetative growth

Factors promoting larch dominance in central Siberia: fire versus growth performance and implications for carbon dynamics at the boundary of evergreen and deciduous conifers

The relative roles of fire and climate in determining canopy species composition and aboveground carbon stocks were investigated. Measurements were made along a transect extending from the dark taiga zone of Central Siberia, where Picea and Abies dominate the 5 canopy, into the Larix zone of Eastern Siberia. We test the hypotheses that the change in canopy species composition is based (1) on climate-driven performance only, (2) on fire only, or (3) on fire-performance interactions. We show that the evergreen conifers Picea obovata and Abies sibirica are the natural late-successional species both in Central and Eastern Siberia, provided there has been no fire for an 10 extended period of time. There are no changes in the climate-driven performance of the observed species. Fire appears to be the main factor explaining the dominance of Larix. Of lesser influence were longitude, hydrology and active-layer thickness. Stand-replacing fires decreased from 300 to 50 yr between the Yenisei Ridge and the upper Tunguska. Repeated non-stand-replacing surface fires eliminated the regenera15 tion of Abies and Picea. With every 100 yr since the last fire, the percentage of Larix decreased by 20 %. Biomass of stems of single trees did not show signs of age-related decline. Relative diameter increment was 0.41±0.20% at breast height and stem volume increased linearly over time with a rate of about 0.36 tCha−1 yr−1 independent of age class and 20 species. Stand volumes reached about 130 tCha−1 (equivalent to about 520m3 ha−1). Individual trees of Larix were older than 600 yr. The maximum age and biomass seemed to be limited by fungal rot of heart wood. 60% of old Larix and Picea and 30% of Pinus sibirica trees were affected by stem rot. Implications for the future role of fire and of plant diseases are discussed.JRC.H.3-Forest Resources and Climat

Deep Visual Proteomics defines single-cell identity and heterogeneity

Peer reviewe

ARDD 2020: from aging mechanisms to interventions

Aging is emerging as a druggable target with growing interest from academia, industry and investors. New technologies such as artificial intelligence and advanced screening techniques, as well as a strong influence from the industry sector may lead to novel discoveries to treat age-related diseases. The present review summarizes presentations from the 7th Annual Aging Research and Drug Discovery (ARDD) meeting, held online on the 1st to 4th of September 2020. The meeting covered topics related to new methodologies to study aging, knowledge about basic mechanisms of longevity, latest interventional strategies to target the aging process as well as discussions about the impact of aging research on society and economy. More than 2000 participants and 65 speakers joined the meeting and we already look forward to an even larger meeting next year. Please mark your calendars for the 8th ARDD meeting that is scheduled for the 31st of August to 3rd of September, 2021, at Columbia University, USA

Intraoperative Radiotherapie des primären Rektumkarzinoms

According to the results of several studies intraoperative radiotherapy seems to influence local control for primary rectal cancer in UICC-Stage II / III positively, though recommendations in therapy cannot be given as studies of high evidence level do not exist. As IORT is rarely available and makes patient recruitment difficult, prospective randomised trials have not been carried out yet. This emphasizes the importance of non-randomised trials for an evaluation of IORT. A comparison of 21 patients with locally advanced rectal cancer who had been treated with intraoperative radiation therapy and 21 similar cases without an application of IORT could not show any significant improvements in prognosis (recurrences, metastases and disease-specific survival). Nevertheless the employment of intraoperative radiation showed a trend in improvement of local control. This hast been shown by several other studies before. Thus the application of IORT in patients with locally advanced rectal cancer is considered a useful part in multimodal treatment and should further be evaluated in specialized centres. In case-control studies 1:1-matching leads to a good comparability of groups and renders conclusions of high internal validity possible. To gain a sufficient power, this type of trials should however primarily be carried out by centres with a high number of cases