Dew formation on the surface of biological soil crusts in central European sand ecosystems

Dew formation was investigated in three developmental stages of biological soil crusts (BSC), which were collected along a catena of an inland dune and in the initial substrate. The Penman equation, which was developed for saturated surfaces, was modified for unsaturated surfaces and used for prediction of dewfall rates. The levels of surface saturation required for this approach were predicted using the water retention functions and the thicknesses of the BSCs. During a first field campaign (2–3 August 2011), dewfall increased from 0.042 kg m<sup>−2</sup> for the initial sandy substrate to 0.058, 0.143 and 0.178 kg m<sup>−2</sup> for crusts 1 to 3, respectively. During a second field campaign (17–18 August 2011), where dew formation was recorded in 1.5 to 2.75-h intervals after installation at 21:30 CEST, dewfall increased from 0.011 kg m<sup>−2</sup> for the initial sandy substrate to 0.013, 0.028 and 0.055 kg m<sup>−2</sup> for crusts 1 to 3, respectively. Dewfall rates remained on low levels for the substrate and for crust 1, and decreased overnight for crusts 2 and 3 (with crust 3 > crust 2 > crust 1 throughout the campaign). Dew formation was well reflected by the model response. The suggested mechanism of dew formation involves a delay in water saturation in near-surface soil pores and extracellular polymeric substances (EPS) where the crusts were thicker and where the water capacity was high, resulting in elevated vapor flux towards the surface. The results also indicate that the amount of dewfall was too low to saturate the BSCs and to observe water flow into deeper soil. Analysis of the soil water retention curves revealed that, despite the sandy mineral matrix, moist crusts clogged by swollen EPS pores exhibited a clay-like behavior. It is hypothesized that BSCs gain double benefit from suppressing their competitors by runoff generation and from improving their water supply by dew collection. Despite higher amounts of dew, the water availability to the crust community decreases with crust development, which may be compensated by ecophysiological adaptation of crust organisms, and which may further suppress higher vegetation or mosses

Types and chemical composition of organic matter in reforested lignite-rich mine soils

20 pages, 4 figures, 6 tables, 49 references.In the post-mining landscapes of Lusatia, forest soils develop from extremely aeid, lignite-rich open cast mine spoils. The sites have been ameliorated with 8sb from lignite-fired power stations prior to afforestation. During stand development, incorporation of plant-derived organic matter leads to an intimate mixture with the substrate-derived lignite in the first centimetres of the soil CAí horizon). The objective of the study was to characterise and to compare the composition of organic matter of mine soils under forest which contain substantial amounts of lignite. Therefore, the forest floor and the mineral soil (Ai and Cv horizon) under a 20-year-old pine and a 36-year-old red oak site were analysed for elemental composition, magnetic susceptibility, chemical structure by cross-polarisation magic angle spinning (CPMAS) I3C and ISN nuclear magnetic resonance (NMR) spectroscopy and lignite content by radiocarbon dating. The 13e CPMAS NMR spectra of!he forest fioor and Ai horizon reveal signals at 56, 72, 105, 119, 130 and 150 ppm, indicating the presence of carbohydrates and lignin ariginating from plant material. Additionally, structures characteristic for lignite material (aromatic and aliphatic carbon) could be observed in the Oh and Ai horizons. Using radiocarbon dating, 25 to 83% of the total carbon in these horizons can be assigned to lignite. Lignite carban may also indicate carbonaceous particles derived from amelioration ash as well as from lignite-derived airborne contamination, which are possible carbon sources of the forest floor and the surface soil. 13C NMR and radiocarbon dating show that the subsoil Cv horizon. is dominated by carbon derived from lignite. From these results it is concluded that mine soils, rich in lignite contain up to four organic matter types, namely lignite inherent to the parent substrate, organic matter derived from decomposition of plant residues, carbonaceous particles in amelioration ash and carbonaceous particles from airborne lignite-derived contamination. 15N NMR spectroscopy revealed that most of the nitrogen of these soils is of recent biogenic origin.Peer reviewe

Aktuelle Therapie der Cholezysto- und Choledocholithiasis – Umfrageergebnisse mit Analyse von 16615 Eingriffen in Bayern

BACKGROUND AND METHODS: The aim of this study was the evaluation of the management of cholecysto- and choledocholithiasis and outcome of laparoscopic as well as open cholecystectomy (CHE) and common bile duct (CBD) exploration in Bavaria, Germany. A written questionnaire including 201 structured items was sent to all 180 hospitals and departments performing general or abdominal surgery in Bavaria. RESULTS: The response rate was 60 %. A total of 16 615 operations for gallstone disease including 16 051 cholecystectomies and 453 CBD explorations with or without cholecystectomy were reported. 88 % of all cholcystectomies started laparoscopically, the conversion rate was 5.6 %. The Veres needle (69 %), 4 trocar techniques and electrosurgical hook knife were reported as standard procedures. A retrieval bag was used by 53 % of all surgeons. The overall complication rate for cholecystectomy was 5.46 % including 0.15 % major bile duct injuries. Relaparoscopy was performed in 0.35 %, relaparotomy in 0.44 % and postoperative treatment by ERC in 1.45 %. The overall hospital mortality rate was 0.13 %. When choledocholithiasis was suspected, a two-stage management ("therapeutic splitting") with preoperative ERC was preferred (99 %). The conversion rate of simultaneous laparoscopic CHE+CBD exploration was 43 %. CONCLUSION: These results allow an estimation of the frequency and overall risks in surgical therapy for gallstones. At present, new techniques like combined laparoscopic and endoscopic procedures, microinstruments or N.O.T.E.S do not play a significant role in Germany

The heat capacity and entropy of the metastable lithium silicide Li₁₅Si₄ in the temperature range (2 to 615) K

This contribution presents the heat capacity of metastable Li15Si4 as a function of temperature in a range from (2 to 615) K. The measurements were performed using two different calorimeters depending on their specification. In the low temperature region from (2 to 300) K a calorimetric method based on a relaxation technique was used, whereas for the high temperature region from (300 to 615) K, DSC measurements applying the C-p-by-step method were carried out. The experimental data are given with an accuracy better than +/- 2% above 5 K and up to 9% below 5 K. The measurement at low temperatures allow the calculation of the standard entropy and entropy of formation as well as temperature coefficients of electronic and lattice contributions to the heat capacity. The results represent a significant contribution to the data basis for thermodynamic calculations (e.g. CALPHAD) and to the understanding of electro-chemical equilibria in the Li-Si-system. (C) 2017 Elsevier Ltd