Determinants of soil organic matter chemistry in maritime temperate forest ecosystems

While the influence of climate, vegetation, management and abiotic site factors on total carbon budgets and turn-over is intensively assessed, the influences of these ecosystem properties on the chemical complexity of soil organic matter (SOM) remains poorly understood. This study addresses the chemical composition of NaOH-extracted SOM from maritime temperate forest sites in Flanders (Belgium) by pyrolysis-GC/MS. The studied forests were chosen based on dominant tree species (Pinus sylvestris, Fagus sylvatica, Quercus robur and Populus spp.), soil texture and soil-moisture conditions. Differences in extractable-SOM pyrolysis products were correlated to site variables including dominant tree species, management of the woody biomass, site history, soil properties, total carbon stocks and indicators for microbial activity. Despite of a typical high intercorrelation between these site variables, the influence of the dominant tree species is prominent. The extractable-SOM composition is strongly correlated to litter quality and available nutrients. In nutrient-poor forests with low litter quality, the decomposition of relatively recalcitrant compounds (i.e. short and mid-chain alkanes/alkenes and aromatic compounds) appears hampered, causing a relative accumulation of these compounds in the soil. However, if substrate quality is favorable, no accumulations of recalcitrant compounds were observed, not even under high soil-moisture conditions. Former heathland vegetation still had a profound influence on extractable-SOM chemistry of young pine forests after a minimum of 60 year

The Impact Of Tax Benefit Systems On Low Income Households In The Benelux Countries. A Simulation Approach Using Synthetic Datasets

Computing the tax-benefit position of similar typical households across countries is a method widely used in comparative fiscal- and social policy research. These calculations provide convenient summary pictures of certain aspects of tax-benefit systems. They can, however, be seriously misleading because they reduce very complex systems to single point estimates. Using an integrated European tax-benefit model (EUROMOD), we substitute the typical household by a synthetic dataset, which can be used across countries. By varying certain important household characteristics (notably income), this dataset captures a much larger range of household situations. The calculations performed on this range of households not only show the tax-benefit position of many individual households but also demonstrate which household characteristics determine taxes and benefits in each country. Hypothetical calculations such as those presented here do not exploit the ability of EUROMOD to determine the impact of social and fiscal policies on actual populations. Nevertheless, they can be a valuable contribution to understanding tax-benefit systems since they allow us to separate the effects of tax-benefit rules from those of the population structure. We compute and compare disposable incomes for a large range of pre-tax-and-benefit income (so called budget constraints) of households in the Benelux countries. Disposable incomes are then decomposed to separately show the effects of each simulated tax and transfer payment. Based on these results, we illustrate the performance of the three tax-benefit systems in terms of ensuring a minimum level of household income.European Union, Microsimulation, Poverty, Benelux, Average Production Worker

Exploration of the taxonomy of some Pleistocene Cervini (Mammalia, Artiodactyla, Cervidae) from Java and Sumatra (Indonesia): a geometric- and linear morphometric approach

Third molars of extant- and fossil Southeast Asian deer were metrically compared using a linear- and geometric morphometric approach and discussed in relation to known taxonomic information from the literature. Our analysis suggests the presence of medium sized deer of the genus Axis and large sized taxa of the genus Cervus s. l. in Java. Axis lydekkeri and Axis javanicus are considered valid taxa, with A. lydekkeri probably related to the subgenus Hyelaphus. The large deer, such as Cervus kendengensis, Cervus stehlini and Cervus problematicus are most likely of the subgenus Rusa, the former two closely related to extant Cervus timorensis. The Sumatran fossils are members of the subgenus Rusa, but not necessarily conspecific with extant Cervus (Rusa) unicolor

Social structure and lexical uniformity: A case study of gender differences in the Kata Kolok community

Language emergence is characterized by a high degree of lex- ical variation. It has been suggested that the speed at which lexical conventionalization occurs depends partially on social structure. In large communities, individuals receive input from many sources, creating a pressure for lexical convergence. In small, insular communities, individuals can remember id- iolects and share common ground with interlocuters, allow- ing these communities to retain a high degree of lexical vari- ation. We look at lexical variation in Kata Kolok, a sign lan- guage which emerged six generations ago in a Balinese vil- lage, where women tend to have more tightly-knit social net- works than men. We test if there are differing degrees of lexical uniformity between women and men by reanalyzing a picture description task in Kata Kolok. We find that women’s produc- tions exhibit less lexical uniformity than men’s. One possible explanation of this finding is that women’s more tightly-knit social networks allow for remembering idiolects, alleviating the pressure for lexical convergence, but social network data from the Kata Kolok community is needed to support this ex- planation

Arbuscular mycorrhizal fungi for the biocontrol of plant-parasitic nematodes: a review of the mechanisms involved

Arbuscular mycorrhizal fungi (AMF) are obligate root symbionts that can protect their host plant against biotic stress factors such as plant-parasitic nematode (PPN) infection. PPN consist of a wide range of species with different life styles that can cause major damage in many important crops worldwide. Various mechanisms have been proposed to play a role in the biocontrol effect of AMF against PPN. This review presents an overview of the different mechanisms that have been proposed, and discusses into more detail the plausibility of their involvement in the biocontrol against PPN specifically. The proposed mechanisms include enhanced plant tolerance, direct competition for nutrients and space, induced systemic resistance (ISR) and altered rhizosphere interactions. Recent studies have emphasized the importance of ISR in biocontrol and are increasingly placing rhizosphere effects on the foreground as well, both of which will be the focal point of this review. Though AMF are not yet widely used in conventional agriculture, recent data help to develop a better insight into the modes of action, which will eventually lead toward future field applications of AMF against PPN. The scientific community has entered an exciting era that provides the tools to actually unravel the underlying molecular mechanisms, making this a timely opportunity for a review of our current knowledge and the challenges ahead