The structure of gallery networks in the nests of termite <Emphasis Type="Italic">Cubitermes</Emphasis> spp. revealed by X-ray tomography

Recent studies have introduced computer tomography (CT) as a tool for the visualisation and characterisation of insect architectures. Here, we use CT to map the three-dimensional networks of galleries inside Cubitermes nests in order to analyse them with tools from graph theory. The structure of these networks indicates that connections inside the nest are rearranged during the whole nest life. The functional analysis reveals that the final network topology represents an excellent compromise between efficient connectivity inside the nest and defence against attacking predators. We further discuss and illustrate the usefulness of CT to disentangle environmental and specific influences on nest architecture.     

Ecological benefits of the alley cropping agroforestry system in sensitive regions of Europe

Alley cropping is an agroforestry system that offers a promising land use alternative for the temperate zone. On the same field, the sustainable production of food and biomass is possible, while simultaneously, especially in marginal areas, the ecological function of the landscape can be improved. Thus, alley cropping corresponds with the increasing demand for renewable energy resources and for a specific adaptation to the predicted changes of climatic conditions within Central Europe.However, presently, little knowledge exists regarding the effects of alley cropping on the environment. In this study a literature survey was undertaken to provide an overview of the different ecological benefits arising from alley cropping systems within temperate Europe. Abiotic factors (nutrient cycle, microclimate), biotic factors (biodiversity) and the effects on the carbon cycle are discussed in detail.Summarising, the results showed that alley cropping may be an ecologically advantageous land use system for sustainable food and biomass production in comparison with conventional agricultural practices. As a very flexible, but low-input system, alley cropping can supply biomass resources in a sustainable way and at the same time provide ecological benefits.     

Bioreactor systems for thermophilic fermentative hydrogen production: evaluation and comparison of appropriate systems

Numerous different bioreactor systems are applied for hydrogen production by dark fermentation. Thermophilic fermentations are gaining an increased interest due to the high hydrogen yields associated with them. In order to reach the best thermophilic fermentation system, 2 types of bioreactors, a trickling bed and a fluidized bed system, were constructed and operated under similar conditions. Both systems were designed to meet the requirements of thermophilic fermentations, such as reduction of hydrogen partial pressure, system immanence as its best as well as increasing cell densities. For comparing the 2 systems, the extreme thermophilic organism Caldicellulosiruptor owensensis OL^T and a glucose-containing medium were employed. Parameters like hydraulic retention time, glucose concentration and stripping gas amount were varied. Each bioreactor system exhibited certain advantages; the trickling bed system enabled yields close to 3 mol-H₂ (mol-glucose)^?1 and productivities of 0.2 L L^?1 h^?1, but the application of stripping gas seemed to be obligatory. The fermentations in the fluidized bed system were characterized by slightly higher productivities (0.25 L L^?1 h^?1), but generally lower yields. However, operation of this system without stripping gas was possible.     

High-field 1H T1 and T2 NMR relaxation time measurements of H2O in homeopathic preparations of quartz, sulfur, and copper sulfate

Quantitative meta-analyses of randomized clinical trials investigating the specific therapeutic efficacy of homeopathic remedies yielded statistically significant differences compared to placebo. Since the remedies used contained mostly only very low concentrations of pharmacologically active compounds, these effects cannot be accounted for within the framework of current pharmacology. Theories to explain clinical effects of homeopathic remedies are partially based upon changes in diluent structure. To investigate the latter, we measured for the first time high-field (600/500 MHz) ¹H T₁ and T₂ nuclear magnetic resonance relaxation times of H₂O in homeopathic preparations with concurrent contamination control by inductively coupled plasma mass spectrometry (ICP-MS). Homeopathic preparations of quartz (10c–30c, n = 21, corresponding to iterative dilutions of 100⁻¹⁰–100⁻³⁰), sulfur (13x–30x, n = 18, 10⁻¹³–10⁻³⁰), and copper sulfate (11c–30c, n = 20, 100⁻¹¹–100⁻³⁰) were compared to n = 10 independent controls each (analogously agitated dilution medium) in randomized and blinded experiments. In none of the samples, the concentration of any element analyzed by ICP-MS exceeded 10 ppb. In the first measurement series (600 MHz), there was a significant increase in T₁ for all samples as a function of time, and there were no significant differences between homeopathic potencies and controls. In the second measurement series (500 MHz) 1 year after preparation, we observed statistically significant increased T₁ relaxation times for homeopathic sulfur preparations compared to controls. Fifteen out of 18 correlations between sample triplicates were higher for controls than for homeopathic preparations. No conclusive explanation for these phenomena can be given at present. Possible hypotheses involve differential leaching from the measurement vessel walls or a change in water molecule dynamics, i.e., in rotational correlation time and/or diffusion. Homeopathic preparations thus may exhibit specific physicochemical properties that need to be determined in detail in future investigations. Electronic supplementary material  The online version of this article (doi:) contains supplementary material, which is available to authorized users.     

Non-specific association between filamentous bacteria and fungus-growing ants

Fungus-growing ants and their fungal cultivar form a highly evolved mutualism that is negatively affected by the specialized parasitic fungus Escovopsis. Filamentous Pseudonocardia bacteria occurring on the cuticle of attine ants have been proposed to form a mutualistic interaction with these ants in which they are vertically transmitted (i.e. from parent to offspring colonies). Given a strictly vertical transmission of Pseudonocardia, the evolutionary theory predicts a reduced genetic variability of symbionts among ant lineages. The aim of this study was to verify whether actinomycetes, which occur on Acromyrmex octospinosus leaf-cutting ants, meet this expectation by comparing their genotypic variability with restriction fragment length polymorphisms. Multiple actinomycete strains could be isolated from both individual ant workers and colonies (one to seven strains per colony). The colony specificity of actinomycete communities was high: Only 15% of all strains were isolated from more than one colony, and just 5% were present in both populations investigated. Partial sequencing of 16S ribosomal deoxyribonucleic acid of two of the isolated strains assigned both of them to the genus Streptomyces. Actinomycetes could also be isolated from workers of the two non-attine ant species Myrmica rugulosa and Lasius flavus. Sixty-two percent of the strains derived from attine ants and 80% of the strains isolated from non-attine ants inhibited the growth of Escovopsis. Our data suggest that the association between attine ants and their actinomycete symbionts is less specific then previously thought. Soil-dwelling actinomycetes may have been dynamically recruited from the environment (horizontal transmission), probably reflecting an adaptation to a diverse community of microbial pathogens.     

Winged queens replaced by reproductives smaller than workers in <Emphasis Type="Italic">Mystrium</Emphasis> ants

In ants, winged queens that are specialized for independent colony foundation can be replaced by wingless reproductives better adapted for colony fission. We studied this shift in reproductive strategy by comparing two Mystrium species from Madagascar using morphometry, allometry and dissections. Mystrium rogeri has a single dealate queen in each colony with a larger thorax than workers and similar mandibles that allow these queens to hunt during non-claustral foundation. In contrast, Mystrium ‘red’ lacks winged queens and half of the female adults belong to a wingless ‘intermorph’ caste smaller and allometrically distinct from the workers. Intermorphs have functional ovaries and spermatheca while those of workers are degenerate. Intermorphs care for brood and a few mate and reproduce making them an all-purpose caste that takes charge of both work and reproduction. However, their mandibles are reduced and inappropriate for hunting centipedes, unlike the workers’ mandibles. This together with their small thorax disallow them to perform independent colony foundation, and colonies reproduce by fission. M. rogeri workers have mandibles polymorphic in size and shape, which allow for all tasks from brood care to hunting. In M. ‘red’, colonial investment in reproduction has shifted from producing expensive winged queens to more numerous helpers. M. ‘red’ intermorphs are the first case of reproductives smaller than workers in ants and illustrate their potential to diversify their caste system for better colonial economy.     

Regional,seasonal and interspecific variation in <Superscript>15</Superscript>N and <Superscript>13</Superscript>C in sympatric mouse lemurs

Madagascar provides some of the rare examples where two or more primate species of the same genus and with seemingly identical niche requirements occur in sympatry. If congeneric primate species co-occur in other parts of the world, they differ in size in a way that is consistent with Hutchinson’s rule for coexisting species, or they occupy different ecological niches. In some areas of Madagascar, mouse lemurs do not follow these “rules” and thus seem to violate one of the principles of community ecology. In order to understand the mechanisms that allow coexistence of sympatric congeneric species without obvious niche differentiation, we studied food composition of two identical sized omnivorous mouse lemur species, Microcebus griseorufus and M. murinus with the help of stable isotope analyses (δ ¹⁵N and δ ¹³C). The two species are closely related sister species. During the rich season, when food seems abundant, the two species do not differ in their nitrogen isotope composition, indicating that the two species occupy the same trophic level. But they differ in their δ ¹³C values, indicating that M. griseorufus feeds more on C₄ and CAM (Crassulacean-acid-metabolism) plants than M. murinus. During the lean season, M. murinus has lower δ ¹⁵N values, indicating that the two species feed at different trophic levels during times of food shortage. Hybrids between the two species showed intermediate food composition. The results reflect subtle differences in foraging or metabolic adaptations that are difficult to quantify by traditional observations but that represent possibilities to allow coexistence of species.     

Permanganate oxidation of polycyclic aromatic compounds (PAHs and polar PACs): column experiments with DNAPL at residual saturation

Environmental Science and Pollution Research - Permanganate is an oxidant usually applied for in situ soil remediation due to its persistence underground. It has already shown great efficiency for...     

Green financing,interrupted. Potential directions for sustainable finance in Luxembourg

ABSTRACT

This paper has a quintessentially explorative character. It aims at identifying existing as well as potential (yet missing) links between the finance industry and local businesses that aspire to more sustainable economic practices. Building on the observation that green investments have been gaining weight in global investors’ strategies, we analyse how sustainable – in the most comprehensive sense of the word – green investments could ultimately be(come), when green assets are still managed according to the logic of “financialised finance”. This latter’s technologies of commodification, securitisation and derivatives-trading allegedly oppose alternative economic practices that pursue economic sustainability through social and environmental gains. In contrast, we investigate how the finance industry relates to alternative financial practices, products and organisations that offer sustainability-oriented financing services, – for example, regional banks, cooperatives and the like, – with a specific focus on green, social and solidarity businesses. Both approaches subscribe to apparently contradictory ideologies. We establish a beneficial dialogue between the opposing models of “green capitalism” and “alternative economies” so as to identify potential points of intersection. The context of Luxembourg’s local/regional economies provides a great opportunity to empirically access three levels of investigation: the private sector, the public sector and an international financial centre, a key facilitator for green finance, thus utilising insights from the concept of bricolage. Whilst supporters of Luxembourg’s emerging green finance profile recognise its positive impact on the small country’s national branding, in combination with economic stimuli, more critical commentators point to pure “green washing” effects.