Illuminating the dark corridor in graphene: polarization dependence of angle-resolved photoemission spectroscopy on graphene

We have used s- and p-polarized synchrotron radiation to image the electronic structure of epitaxial graphene near the K-point by angular resolved photoemission spectroscopy (ARPES). Part of the experimental Fermi surface is suppressed due to the interference of photoelectrons emitted from the two equivalent carbon atoms per unit cell of graphene's honeycomb lattice. Here we show that by rotating the polarization vector, we are able to illuminate this 'dark corridor' indicating that the present theoretical understanding is oversimplified. Our measurements are supported by first-principles photoemission calculations, which reveal that the observed effect persists in the low photon energy regime.Comment: 5 pages, 4 figure

Optical gap in herringbone and pi-stacked crystals of 1]benzothieno3,2-b]benzothiophene and its brominated derivative

The optical gap of the organic semiconductor 1]benzothieno3,2-b]benzothiophene and its 2,7-dibrominated analogue is measured in solution and in the crystalline state by means of UV-vis and emission spectroscopy. Bromination leads to a change in molecular packing from herringbone to pi-stacked, resulting in a marked shift in the absorption and emission spectra which is found to be in accordance with TDDFT calculations

Recycling and Assessment of Struvite Phosphorus from Sewage Sludge

AbstractThis study presents an integrated approach for the recovery of P from the wastewater path. Since natural P sources are limited, recycling processes are making an increasingly important contribution to meeting the nutritional requirements of plant production. The groundwork for developing a new fertilizer from upgraded sewage sludge includes an evaluation of nutrients and heavy metal contents. Struvite (NH4MgPO4 • 6 H2O) derived from sewage sludge had a total P content of 6.1% with 3.5% being water-soluble. Plant availability was tested in pot experiments with wheat and maize. P uptake rates were 66.7% and 85.9%, respectively. In terms of heavy metal contents, struvite showed contaminant levels at least three times below the limiting values of the German Sewage Sludge Ordinance. Stricter rules of the German Federal Soil Protection Act are also fulfilled if the loading of heavy metals is considered during periodical fertilization. This implies that P recovery as struvite may be one way of declaring a new type of fertilizer.

Representativeness of European biochar research : part II – pot and laboratory studies

Biochar research is extensive and there are many pot and laboratory studies carried out in Europe to investigate the mechanistic understanding that govern its impact on soil processes. A survey was conducted in order to find out how representative these studies under controlled experimental conditions are of actual environmental conditions in Europe and biomass availability and conversion technologies. The survey consisted of various key questions related to types of soil and biochar used, experimental conditions and effects of biochar additions on soil chemical, biological and physical properties. This representativeness study showed that soil texture and soil organic carbon contents used by researchers are well reflected in the current biochar research in Europe (through comparison with published literature), but less so for soil pH and soil type. This study provides scope for future work to complement existing research findings, avoiding unnecessary repetitions and highlighting existing research gaps.Peer reviewe

Representativeness of European biochar research : Part I - field experiments

A representativeness survey of existing European Biochar field experiments within the Biochar COST Action TD1107 was conducted to gather key information for setting up future experiments and collaborations, and to minimise duplication of efforts amongst European researchers. Woody feedstock biochar, applied without organic or inorganic fertiliser appears over-represented compared to other categories, especially considering the availability of crop residues, manures, and other organic waste streams and the efforts towards achieving a zero waste economy. Fertile arable soils were also over-represented while shallow unfertile soils were under-represented. Many of the latter are likely in agroforestry or forest plantation land use. The most studied theme was crop production. However, other themes that can provide evidence of mechanisms, as well as potential undesired side-effects, were relatively well represented. Biochar use for soil contamination remediation was the least represented theme; further work is needed to identify which specific contaminants, or mixtures of contaminants, have the potential for remediation by different biochars.Peer reviewe

Global change effects on plant communities are magnified by time and the number of global change factors imposed

Global change drivers (GCDs) are expected to alter community structure and consequently, the services that ecosystems provide. Yet, few experimental investigations have examined effects of GCDs on plant community structure across multiple ecosystem types, and those that do exist present conflicting patterns. In an unprecedented global synthesis of over 100 experiments that manipulated factors linked to GCDs, we show that herbaceous plant community responses depend on experimental manipulation length and number of factors manipulated. We found that plant communities are fairly resistant to experimentally manipulated GCDs in the short term (<10 y). In contrast, long-term (≥10 y) experiments show increasing community divergence of treatments from control conditions. Surprisingly, these community responses occurred with similar frequency across the GCD types manipulated in our database. However, community responses were more common when 3 or more GCDs were simultaneously manipulated, suggesting the emergence of additive or synergistic effects of multiple drivers, particularly over long time periods. In half of the cases, GCD manipulations caused a difference in community composition without a corresponding species richness difference, indicating that species reordering or replacement is an important mechanism of community responses to GCDs and should be given greater consideration when examining consequences of GCDs for the biodiversity–ecosystem function relationship. Human activities are currently driving unparalleled global changes worldwide. Our analyses provide the most comprehensive evidence to date that these human activities may have widespread impacts on plant community composition globally, which will increase in frequency over time and be greater in areas where communities face multiple GCDs simultaneously

Common variants in Alzheimer's disease and risk stratification by polygenic risk scores.

Funder: Funder: Fundación bancaria ‘La Caixa’ Number: LCF/PR/PR16/51110003 Funder: Grifols SA Number: LCF/PR/PR16/51110003 Funder: European Union/EFPIA Innovative Medicines Initiative Joint Number: 115975 Funder: JPco-fuND FP-829-029 Number: 733051061Genetic discoveries of Alzheimer's disease are the drivers of our understanding, and together with polygenetic risk stratification can contribute towards planning of feasible and efficient preventive and curative clinical trials. We first perform a large genetic association study by merging all available case-control datasets and by-proxy study results (discovery n = 409,435 and validation size n = 58,190). Here, we add six variants associated with Alzheimer's disease risk (near APP, CHRNE, PRKD3/NDUFAF7, PLCG2 and two exonic variants in the SHARPIN gene). Assessment of the polygenic risk score and stratifying by APOE reveal a 4 to 5.5 years difference in median age at onset of Alzheimer's disease patients in APOE ɛ4 carriers. Because of this study, the underlying mechanisms of APP can be studied to refine the amyloid cascade and the polygenic risk score provides a tool to select individuals at high risk of Alzheimer's disease

Economic cooperation with Vietnam Improving the framework for foreign direct investment

Im vorliegenden Forschungsbericht werden die Rahmenbedingungen Vietnams fuer eine auslaendische Direktinvestition (FDI) untersucht, wobei die Autoren exemplarisch auf die Industriezweige der Lebensmittelverarbeitung, Bekleidung und Elektronik eingehen. Die Voraussetzungen Vietnams fuer FDI umfassen ein breites Spektrum von Themenbereichen, aus denen sechs Gesichtspunkte naeher betrachtet werden: das Handelsregime, das Finanzregime, die gesetzlichen Regelungen, die oekonomischen Anreize von Besteuerung und Investment, die institutionelle Voraussetzung und die physikalische Infrastruktur. Die Autoren gehen in ihrer empirischen Untersuchung, die auf einer umfangreichen Dokumentenanalyse sowie auf Befragungen auslaendischer Investoren und vietnamesischer Unternehmer beruht, der Frage nach, welche spezifischen Rahmenbedingungen die Attraktivitaet des Landes fuer auslaendische Investoren verringern und die Bereitschaft von FDI begrenzen, einen Beitrag zu Wachstum und Entwicklung zu leisten. Auf der Grundlage der empirischen Ergebnisse werden abschliessend politische Herausforderungen fuer die vietnamesischen Entscheider und Auswirkungen fuer die Entwicklungshilfe aufgezeigt. (ICI)German title: Wirtschaftskooperation mit Vietnam: den Rahmen fuer auslaendische Direktinvestition verbessernAvailable from UuStB Koeln(38)-20010106127 / FIZ - Fachinformationszzentrum Karlsruhe / TIB - Technische InformationsbibliothekSIGLEDEGerman