Highly modular pattern in ant-plant interactions involving specialized and non-specialized myrmecophytes

Because Tachia guianensis (Gentianaceae) is a “non-specialized myrmecophyte” associated with 37 ant species, we aimed to determine if its presence alters the ant guild associated with sympatric “specialized myrmecophytes” (i.e., plants sheltering a few ant species in hollow structures). The study was conducted in a hilly zone of a neotropical rainforest where two specialized myrmecophytes grow at the bottom of the slopes, another at mid-slope, and a fourth on the hilltops. Tachia guianensis, which occurred everywhere, had its own guild of associated ant species. A network analysis showed that its connections with the four other myrmecophytes were rare and weak, the whole resulting in a highly modular pattern of interactions with one module (i.e., subnetwork) per myrmecophyte. Three ant species parasitized three out of the four specialized myrmecophytes (low nestedness noted), but were not or barely associated with T. guianensis that therefore did not influence the parasitism of specialized myrmecophytes.     

Kin associations and direct vs indirect fitness benefits in colonial cooperatively breeding sociable weavers Philetairus socius

Indirect fitness benefits are believed to be an important force behind the evolution of cooperative breeding. However, helpers may associate with their relatives as a result of delayed dispersal, hence, kin associations might be a consequence of demographic viscosity rather than active choice. In addition, recent studies showed that helpers may have access to reproduction therefore direct benefits might also play an important role. Here, we investigate the possible roles of direct genetic benefits and kin associations on helping behavior in the sociable weaver Philetairus socius, a colonial and cooperatively breeding passerine. We used a microsatellite-based genotyping method to describe the genetic structure within nests and colonies. Within a colony, we found considerable genetic structure between males but not females. Sociable weaver colonies have several nests that are simultaneously active, giving individuals a choice of associating with a range of first-order kin to unrelated individuals. Helpers were significantly more related to the young in the helped nests than in other nests of the colony, suggesting an active choice for associating with kin. The helpers were generally offspring or first-order relatives of one (50%) or both (43%) breeders, although more infrequently, seemingly unrelated individuals also helped (7%). We found no supporting evidence of extrapair parentage and hence no direct genetic gains from helping in our population. This strong reproductive skew is contrary to theoretical models predicting conflicts over reproduction in stepfamilies. We discuss whether female decisions and/or other direct benefits of remaining in kin associations or helping might explain the high skew observed.     

Haemolymph constituent levels and ammonia efflux rates of Nephrops norvegicus during emersion

Nephropsnorvegicus (L.) were subjected to 8 h of emersion, either between layers of seawater-soaked hessian with periodical (20 min) flushes of seawater (high humidity, HH) or to unprotected emersion (low humidity, LH). Blood ammonia levels rose during emersion in both groups but reached higher levels under LH conditions. Ammonia efflux rates after re-immersion were higher than those of control prawns, and amounts of ammonia excreted at such times were considerably higher than those calculated to have accumulated in the blood during emersion. Possible explanations for such differences are discussed. C _aO2 and C _vO2 decreased rapidly to ca. 10% normoxia values within 2 h of HH and LH emersion and remained low throughout the remaining emersion time. Emersion-induced tissue hypoxia increased blood concentrations of glucose and lactate. Lactate accumulation was higher during LH emersion, compared with HH emersion. Blood pH dropped ca. 0.40 units but increased again after 2 h of re-immersion. Acidosis was probably related more to respiratory difficulties (CO₂ accumulation) than to lactate accumulation, as blood lactate values remained high after 2 h of re-immersion. The ability of N. norvegicus to cope with emersion appears to be little influenced by high humidity conditions. Received: 26 June 1996 / Accepted: 5 August 1996     

Treatment of domestic wastewater by an hydroponic NFT system

The objectives in this work were to investigate a conceptual layout for an inexpensive and simple system that would treat primary municipal wastewater to discharge standards. A commercial hydroponic system was adapted for this study and the wastewater was used to irrigate Datura innoxia plants. Influent and effluent samples were collected once a month for six months and analysed to determine the various parameters relating to the water quality. The legal discharge levels for total suspended, biochemical oxygen demand and chemical oxygen demand were reached with the plant system after 24 h of wastewater treatment. Total nitrogen and total phosphorus reduction were also obtained. NH4(+)-N was reduced by 93% with nitrification proving to be the predominant removal process. Significant nitrification occurred when the BOD5 level dropped 45 mg/l. Similar results were obtained for six months although the sewage composition varied widely. D. innoxia develops and uses the wastewater as the unique nutritive source.     

A Stochastic Dynamic Game of Carbon Emissions Trading

This paper proposes a computable stochastic equilibrium model to represent the possible competition between Russia and China on the international market of carbon emissions permits. The model includes a representation of the uncertainty concerning the date of entry of developing countries (e.g., China) on this market in the form of an event tree. Assuming that this date of entry is an uncontrolled event, we model the competition as a dynamic game played on an event tree and we look for a solution called S-adapted equilibrium. We compare the solution obtained from realistic data describing the demand curves for permits and the marginal abatement cost curves in different countries, under different market and information structures: (i) Russia's monopoly, (ii) Russia–China competition in a deterministic framework, (iii) Russia–China competition in a stochastic framework. The results show the possible impact of this competition on the pricing of emissions permits and on the effectiveness of Kyoto and post-Kyoto agreements, without a US participation.     

Hepatitis E Virus in Farmed Rabbits,Wild Rabbits and Petting Farm Rabbits in the Netherlands

Rabbits have been suggested as a zoonotic source of Hepatitis E virus. Phylogenetic analysis of HEV isolates from farmed, wild and pet rabbits in the Netherlands (23, 0, and 60 % respectively) showed them to be grouped amongst published rabbit HEV sequences and distinct from most human isolates. Dutch rabbits are unlikely to be a zoonotic source.     

(Why) did Desertec fail? An interim analysis of a large-scale renewable energy infrastructure project from a Social Studies of Technology perspective

ABSTRACT

In 2009 the Desertec Industrial Initiative (DII) was founded by several, predominant German enterprises. The objective of DII was to organise the conditions for the realisation of the Desertec idea, which aimed to both (a) supply Europe, in a large-scale manner, with electricity produced in solar power plants in North Africa and the Arabic peninsula and (b) contribute to the self-supply of the Middle East North Africa region (MENA). Protagonists of the desert energy idea saw this megatechnic project as a starting point for a new trans-Mediterranean EU-MENA union, critics in contrast as a neo-colonial project. Disputes over the adequate interpretation and implementation of the Desertec idea broke out from the beginning. In 2014/2015, the media talked of the failure of DII and of the Desertec concept. The majority of the members left DII at the end of 2014. On the other hand, in some MENA countries renewables are playing a crucial role in securing the future of the energy sector. This paper analyses the development of DII and the Desertec idea by using concepts from Social Studies in Technology, and especially by the multi-level perspective approach in Transition Studies. It shows how the interplay of different factors, such as technological developments, entrepreneurial performances and political processes, lead to internal conflicts and the non-realisation – up to now – of related large-scale energy projects. As an important aspect of the paper, different understandings of the future of our energy supply and of North–South relations are presented in detail.     

Butterfly community shifts over two centuries

Environmental changes strongly impact the distribution of species and subsequently the composition of species assemblages. Although most community ecology studies represent temporal snap shots, long‐term observations are rather rare. However, only such time series allow the identification of species composition shifts over several decades or even centuries. We analyzed changes in the species composition of a southeastern German butterfly and burnet moth community over nearly 2 centuries (1840–2013). We classified all species observed over this period according to their ecological tolerance, thereby assessing their degree of habitat specialisation. This classification was based on traits of the butterfly and burnet moth species and on their larval host plants. We collected data on temperature and precipitation for our study area over the same period. The number of species declined substantially from 1840 (117 species) to 2013 (71 species). The proportion of habitat specialists decreased, and most of these are currently endangered. In contrast, the proportion of habitat generalists increased. Species with restricted dispersal behavior and species in need of areas poor in soil nutrients had severe losses. Furthermore, our data indicated a decrease in species composition similarity between different decades over time. These data on species composition changes and the general trends of modifications may reflect effects from climate change and atmospheric nitrogen loads, as indicated by the ecological characteristics of host plant species and local changes in habitat configuration with increasing fragmentation. Our observation of major declines over time of currently threatened and protected species shows the importance of efficient conservation strategies.     

Occupational exposure in the fluorescent lamp recycling sector in France

The fluorescent lamp recycling sector is growing considerably in Europe due to increasingly strict regulations aimed at inciting the consumption of low energy light bulbs and their end-of-life management. Chemical risks were assessed in fluorescent lamp recycling facilities by field measurement surveys in France, highlighting that occupational exposure and pollutant levels in the working environment were correlated with the main recycling steps and processes.The mean levels of worker exposure are 4.4 mg/m³, 15.4 μg/m³, 14.0 μg/m³, 247.6 μg/m³, respectively, for total inhalable dust, mercury, lead and yttrium. The mean levels of airborne pollutants are 3.1 mg/m³, 9.0 μg/m³, 9.0 μg/m³, 219.2 μg/m³, respectively, for total inhalable dust, mercury, lead and yttrium. The ranges are very wide. Surface samples from employees’ skin and granulometric analysis were also carried out. The overview shows that all the stages and processes involved in lamp recycling are concerned by the risk of hazardous substances penetrating into the bodies of employees, although exposure of the latter varies depending on the processes and tasks they perform. The conclusion of this study strongly recommends the development of a new generation of processes in parallel with more information sharing and regulatory measures.