Electrically gauged N=4 supergravities in D=4 with N=2 vacua

We study N=2 vacua in spontaneously broken N=4 electrically gauged supergravities in four space-time dimensions. We argue that the classification of all such solutions amounts to solving a system of purely algebraic equations. We then explicitly construct a special class of consistent N=2 solutions and study their properties. In particular we find that the spectrum assembles in N=2 massless or BPS supermultiplets. We show that (modulo U(1) factors) arbitrary unbroken gauge groups can be realized provided that the number of N=4 vector multiplets is large enough. Below the scale of partial supersymmetry breaking we calculate the relevant terms of the low-energy effective action and argue that the special Kahler manifold for vector multiplets is completely determined, up to its dimension, and lies in the unique series of special Kahler product manifolds.Comment: 48 pages; v2: one reference adde

Direct Electron Microscopy Study on the Morphological Diversity of Bacteriophage Populations in Lake Plußsee

Direct electron microscopy of bacteriophages adsorbed to a carbon film without prior enrichment by specific host strains or concentration by physical or chemical methods was used to study the morphological diversity of natural bacteriophage assemblages in a North German lake. All samples contained a mixture of morphologically different tailed viruses, which were regarded as bacteriophages. Most of them had isometric heads and long noncontractile tails, belonging to morphotype B1 (Siphoviridae). In addition, members of morphotypes A1 (Myoviridae), B2 (Siphoviridae with elongated heads), and C1 (Podoviridae) were present in lower numbers. Only one cubic virus was detected, while no filamentous or pleomorphic phages were found. Up to 11 different phages per sample, and a total of 39 phages when all samples were considered together, could be distinguished by morphological criteria. The total number of phages was estimated to be on the order of 108/ml

Valuing Biodiversity in Life Cycle Impact Assessment

Erratum published on 13 March 2020, see Sustainability 2020, 12(6), 2270. https://doi.org/10.3390/su11205628In this article, the authors propose an impact assessment method for life cycle assessment (LCA) that adheres to established LCA principles for land use-related impact assessment, bridges current research gaps and addresses the requirements of different stakeholders for a methodological framework. The conservation of biodiversity is a priority for humanity, as expressed in the framework of the Sustainable Development Goals (SDGs). Addressing biodiversity across value chains is a key challenge for enabling sustainable production pathways. Life cycle assessment is a standardised approach to assess and compare environmental impacts of products along their value chains. The impact assessment method presented in this article allows the quantification of the impact of land-using production processes on biodiversity for several broad land use classes. It provides a calculation framework with degrees of customisation (e.g., to take into account regional conservation priorities), but also offers a default valuation of biodiversity based on naturalness. The applicability of the method is demonstrated through an example of a consumer product. The main strength of the approach is that it yields highly aggregated information on the biodiversity impacts of products, enabling biodiversity-conscious decisions about raw materials, production routes and end user products

Automatic Recognition of Object Use Based on Wireless Motion Sensors

In this paper, we present a method for automatic, online detection of a user’s interaction with objects. This represents an essential building block for improving the performance of distributed activity recognition systems. Our\ud method is based on correlating features extracted from motion sensors worn by the user and attached to objects. We present a complete implementation of the idea, using miniaturized wireless sensor nodes equipped with motion sensors. We achieve a recognition accuracy of 97% for a target response time of 2 seconds. The implementation is lightweight, with low communication bandwidth and processing needs. We illustrate the potential of the concept by means of an interactive multi-user game

Design of 1480-nm diode-pumped Er3+-doped integrated optical amplifiers

Erbium-doped Y2O3 integrated optical amplifiers are designed for low-threshold operation and 3 dB amplification. The most important design parameter for minimal threshold, the erbium concentration, is found to have an optimum value of 0.35 at% for a given waveguide structure with 1.0 dB cm-1 background loss. The corresponding threshold power is 7 mW. The pump power to obtain 3 dB gain is found to be 22 mW for an amplifier with an optimum erbium concentration of 0.6 at% and 2.8 cm length. At 30 mW pump power the maximum gain is shown to be 5 dB.\ud \ud Designing is done using a comprehensive numerical model of an erbium-doped integrated optical amplifier. In the model two-dimensional intensity-dependent overlap integrals are used, which allow arbitrary erbium dopant profiles and waveguide crosssections. Concentration-dependent effects such as quenching and upconversion are also included in the model.\ud \ud Input parameters for the model are determined from measurements on an unoptimized Er: Y2O3 optical waveguide amplifier. Amplification simulations and gain measurements of the unoptimized waveguides are found to be in close agreement, providing a sound basis for the design calculations

‘Irrigation by night’ in the Eastern Cape, South Africa

This paper addresses water-related issues in the Eastern Cape, South Africa. Irrigation development and providing water for human consumption have been key factors in the country’s rural development planning, notably during the post-apartheid era when the Reconstruction and Development Programme (RDP) and Water Services Act and Free Basic Water of 1997 became effective. By exploring the use of water in rural villages in the central Eastern Cape, the paper addresses the conceptual and practical limitations of the provisioning of water for human consumption and irrigation, in particular, and how this is being handled by various implementing agencies. The paper draws attention to the importance of ‘irrigation by night’ which refers to unplanned and ‘unlawful’ water-use practices. People in villages ‘unlawfully’ re-appropriate piped water for irrigation purposes to produce food and generate some income. The paper proposes a shift away from the rigid conceptualisations that currently form the backbone of planning to instead adopt a multiple-use system (MUS) approach which is more in tune with local practices currently observed in rural villages of South Africa