Energy balance of different organic biogas farming systems

The ecological impact of biogas plants depends on their integration into a given farming system. Therefore only farm-specific and no general statements are possible. In this paper, two different concepts of biogas production for an organic cash crop farm have been energetically balanced using a model software. The analysis of input and efficient use of fossil energy carriers provides information on the environmental relevance of the farm operations. Apart from this, renewable energy production in the farming systems is compared to food production, and changes in the farm output are described. It turns out that organically run cash crop farms can benefit from a reasonable integration of a biogas plant, both in food crop and energy production. An increased orientation on the growing of energy crops, however, leads to worse utilization of fossil energy carriers and reduced food production

Tropical analogues of a Dempe-Franke bilevel optimization problem

We consider the tropical analogues of a particular bilevel optimization problem studied by Dempe and Franke and suggest some methods of solving these new tropical bilevel optimization problems. In particular, it is found that the algorithm developed by Dempe and Franke can be formulated and its validity can be proved in a more general setting, which includes the tropical bilevel optimization problems in question. We also show how the feasible set can be decomposed into a finite number of tropical polyhedra, to which the tropical linear programming solvers can be applied.Comment: 11 pages, 1 figur

E-government and the digital divide: A study of English-as-a-Second-Language Users' Information Behaviour

Internet-based technologies are increasingly used by organisations and governments to offer services to consumers and the public in a quick and efficient manner, removing the need for face-to-face conversations and human advisors. Despite their obvious benefits for most users, these online systems may present barriers of access to certain groups in society which may lead to information poverty. In this study we consider the information behaviour of ten ESL (English as a Second Language) participants as they conduct four search tasks designed to reflect actual information seeking situations. Our results suggest that, despite a perception that they have a good understanding of English, they often choose documents that are only partially or tangentially relevant. There were significant differences in the behaviour of participants given their perceived confidence in using English to perform search tasks. Those who were confident took riskier strategies and were less thorough, leading to them bookmarking a larger proportion of non-relevant documents. The results of this work have potentially profound repercussions for how e-government services are provided and how second-language speakers are assisted in their use of these

Poly-MTO, {(CH_3)_{0.92} Re O_3}_\infty, a Conducting Two-Dimensional Organometallic Oxide

Polymeric methyltrioxorhenium, {(CH_{3})_{0.92}ReO_{3}}_{\infty} (poly-MTO), is the first member of a new class of organometallic hybrids which adopts the structural pattern and physical properties of classical perovskites in two dimensions (2D). We demonstrate how the electronic structure of poly-MTO can be tailored by intercalation of organic donor molecules, such as tetrathiafulvalene (TTF) or bis-(ethylendithio)-tetrathiafulvalene (BEDT-TTF), and by the inorganic acceptor SbF$_3$. Integration of donor molecules leads to a more insulating behavior of poly-MTO, whereas SbF$_3$ insertion does not cause any significant change in the resistivity. The resistivity data of pure poly-MTO is remarkably well described by a two-dimensional electron system. Below 38 K an unusual resistivity behavior, similar to that found in doped cuprates, is observed: The resistivity initially increases approximately as $\rho \sim$ ln$(1/T$) before it changes into a $\sqrt{T}$ dependence below 2 K. As an explanation we suggest a crossover from purely two-dimensional charge-carrier diffusion within the \{ReO$_2$\}$_{\infty}$ planes at high temperatures to three-dimensional diffusion at low temperatures in a disorder-enhanced electron-electron interaction scenario (Altshuler-Aronov correction). Furthermore, a linear positive magnetoresistance was found in the insulating regime, which is caused by spatial localization of itinerant electrons at some of the Re atoms, which formally adopt a $5d^1$ electronic configuration. X-ray diffraction, IR- and ESR-studies, temperature dependent magnetization and specific heat measurements in various magnetic fields suggest that the electronic structure of poly-MTO can safely be approximated by a purely 2D conductor.Comment: 15 pages, 16 figures, 2 table

Global Metal Use Targets in Line with Climate Goals.

Metals underpin essential functions in modern society, yet their production currently intensifies climate change. This paper develops global targets for metal flows, stocks, and use intensity in the global economy out to 2100. These targets are consistent with emissions pathways to achieve a 2 °C climate goal and cover six major metals (iron, aluminum, copper, zinc, lead, and nickel). Results indicate that despite advances in low-carbon metal production, a transformative system change to meet the society's needs with less metal is required to remain within a 2 °C pathway. Globally, demand for goods and services over the 21st century needs to be met with approximately 7 t/capita of metal stock-roughly half the current level in high-income countries. This systemic change will require a peak in global metal production by 2030 and deep decoupling of economic growth from both metal flows and stocks. Importantly, the identified science-based targets are theoretically achievable through such measures as efficient design, more intensive use, and longer product lifetime, but immediate action is crucial before middle- and low-income countries complete full-scale urbanization

Splice-site mutations cause Rrp6-mediated nuclear retention of the unspliced RNAs and transcriptional down-regulation of the splicing-defective genes

Background: Eukaryotic cells have developed surveillance mechanisms to prevent the expression of aberrant transcripts. An early surveillance checkpoint acts at the transcription site and prevents the release of mRNAs that carry processing defects. The exosome subunit Rrp6 is required for this checkpoint in Saccharomyces cerevisiae, but it is not known whether Rrp6 also plays a role in mRNA surveillance in higher eukaryotes. Methodology/Principal Findings: We have developed an in vivo system to study nuclear mRNA surveillance in Drosophila melanogaster. We have produced S2 cells that express a human b-globin gene with mutated splice sites in intron 2 (mut bglobin). The transcripts encoded by the mut b-globin gene are normally spliced at intron 1 but retain intron 2. The levels of the mut b-globin transcripts are much lower than those of wild type (wt) ß-globin mRNAs transcribed from the same promoter. We have compared the expression of the mut and wt b-globin genes to investigate the mechanisms that downregulate the production of defective mRNAs. Both wt and mut b-globin transcripts are processed at the 39, but the mut bglobin transcripts are less efficiently cleaved than the wt transcripts. Moreover, the mut b-globin transcripts are less efficiently released from the transcription site, as shown by FISH, and this defect is restored by depletion of Rrp6 by RNAi. Furthermore, transcription of the mut b-globin gene is significantly impaired as revealed by ChIP experiments that measure the association of the RNA polymerase II with the transcribed genes. We have also shown that the mut b-globin gene shows reduced levels of H3K4me3. Conclusions/Significance: Our results show that there are at least two surveillance responses that operate cotranscriptionally in insect cells and probably in all metazoans. One response requires Rrp6 and results in the inefficient release of defective mRNAs from the transcription site. The other response acts at the transcription level and reduces the synthesis of the defective transcripts through a mechanism that involves histone modifications

Fibre Optic Sensors for the Structural Health Monitoring of Building Structures

AbstractIn this work different fibre optic sensors for the structural health monitoring of civil engineering structures are reported. A fibre optic crack sensor and two different fibre optic moisture sensors have been designed to detect the moisture ingress in concrete based building structures. Moreover, the degeneration of the mechanical properties of optical glass fibre sensors and hence their long-term stability and reliability due to the mechanical and chemical impact of the concrete environment is discussed as well as the advantage of applying a fibre optic sensor system for the structural health monitoring of sewerage tunnels is demonstrated

The Fundamental Plane of Gravitational Lens Galaxies and The Evolution of Early-Type Galaxies in Low Density Environments

Most gravitational lenses are early-type galaxies in relatively low density environments -- a ``field'' rather than a ``cluster'' population. We show that field early-type galaxies with 0 < z < 1, as represented by the lens galaxies, lie on the same fundamental plane as those in rich clusters at similar redshifts. We then use the fundamental plane to measure the combined evolutionary and K-corrections for early-type galaxies in the V, I and H bands. Only for passively evolving stellar populations formed at z > 2 (H_0=65 km/s Mpc, Omega_0=0.3, Lambda_0=0.7) can the lens galaxies be matched to the local fundamental plane. The high formation epoch and the lack of significant differences between the field and cluster populations contradict many current models of the formation history of early-type galaxies. Lens galaxy colors and the fundamental plane provide good photometric redshift estimates with an empirical accuracy of -0.03 +/- 0.11 for the 17 lenses with known redshifts. A mass model dominated by dark matter is more consistent with the data than either an isotropic or radially anisotropic constant M/L mass model, and a radially anisotropic model is better than an isotropic model.Comment: 36 pages, 9 figures, 6 tables. ApJ in press. Final version contains more observational dat