To green or not to green: Establishing the economic value of green infrastructure investments in The Wicker, Sheffield.

Establishing the value of urban green infrastructure resources draws on a complex evaluation of social, economic and ecological influences. As a result planners have found it difficult to develop robust economic arguments to promote investments in urban greening. The Valuing Attractive Landscapes in the Urban Economy (VALUE) project facilitated a trans-national programme of investigations to establish economic values for a range of green infrastructure investments. This paper presents the results of a large-scale willingness to pay (WTP) survey (N: 510) for investments on Blonk Street, The Wicker, Sheffield. Using 3D visualisations of three alternative urban greening scenarios the research addressed the influence of green infrastructure on aesthetic quality, functionality and amenity. The evidence suggests that participants were WTP up £10.56 or 2% more in monthly rent or additional mortgage payments to live in locations that have a high quality green infrastructure environment. The survey also examined the relationships between a range of socio-economic factors and WTP for green infrastructure (GI). WTP more rent was associated particularly with those in younger age groups and those with lower educational attainment. The paper concludes that investment in urban GI that is visibly greener, that facilitates access to GI and other amenities and that is perceived to promote multiple functions and benefits on a single site (i.e. multi-functionality) generate higher WTP values. The findings of the study support the wider literature evaluating the economic value of GI which argues that investment in urban greenspace can have a significant impact on local housing and commercial markets where it produces more attractive and functional landscapes

Molecular evolution under increasing transposable element burden in Drosophila: A speed limit on the evolutionary arms race.

Genome architecture is profoundly influenced by transposable elements (TEs), and natural selection against their harmful effects is a critical factor limiting their spread. Genome defense by the piRNA silencing pathway also plays a crucial role in limiting TE proliferation. How these two forces jointly determine TE abundance is not well understood. To shed light on the nature of factors that predict TE success, we test three distinct hypotheses in the Drosophila genus. First, we determine whether TE abundance and relaxed genome-wide purifying selection on protein sequences are positively correlated. This serves to test the hypothesis that variation in TE abundance in the Drosophila genus can be explained by the strength of natural selection, relative to drift, acting in parallel against mildly deleterious non-synonymous mutations. Second, we test whether increasing TE abundance is correlated with an increased rate of amino-acid evolution in genes encoding the piRNA machinery, as might be predicted by an evolutionary arms race model. Third, we test whether increasing TE abundance is correlated with greater codon bias in genes of the piRNA machinery. This is predicted if increasing TE abundance selects for increased efficiency in the machinery of genome defense

A Development Framework Enabling the Design of Service-Based Cloud Applications

Cloud application platforms gain popularity and have the potential to change the way applications are developed, involving composition of platform basic services. In order to enhance the developer’s experience and reduce the barriers in the software development, a new paradigm of cloud application creation should be adopted. According to that developers are enabled to design their applications, leveraging multiple platform basic services, independently from the target application platforms. To this end, this paper proposes a development framework for the design of service-based cloud applications comprising two main components: the meta-model and the Platform Service Manager. The meta-model describes the building blocks which enable the construction of Platform Service Connectors in a uniform way while the Platform Service Manager coordinates the interaction of the application with the concrete service providers and further facilitates the administration of the deployed platform basic services

Direct Cytoskeleton Forces Cause Membrane Softening in Red Blood Cells

Erythrocytes are flexible cells specialized in the systemic transport of oxygen in vertebrates. This physiological function is connected to their outstanding ability to deform in passing through narrow capillaries. In recent years, there has been an influx of experimental evidence of enhanced cell-shape fluctuations related to metabolically driven activity of the erythroid membrane skeleton. However, no direct observation of the active cytoskeleton forces has yet been reported to our knowledge. Here, we show experimental evidence of the presence of temporally correlated forces superposed over the thermal fluctuations of the erythrocyte membrane. These forces are ATP-dependent and drive enhanced flickering motions in human erythrocytes. Theoretical analyses provide support for a direct force exerted on the membrane by the cytoskeleton nodes as pulses of well-defined average duration. In addition, such metabolically regulated active forces cause global membrane softening, a mechanical attribute related to the functional erythroid deformability

Bridging Temporal Divides: Temporal Brokerage in Global Teams and Its Impact on Individual Performance

Members of global teams are often dispersed across time zones. This paper introduces the construct of temporal brokerage, which we define as being in a position within a team’s temporal structure that bridges subgroups that have little or no temporal overlap with each other. Although temporal brokerage is not a formal role, we argue that occupying such a position makes an individual more likely to take on more coordination work than other members on the team. We suggest that, while engaging in such coordination work has advantages in the form of enhanced integrative complexity, it also comes with costs in the form of a greater workload relative to other members. We further argue that the increased integrative complexity and workload that result from occupying a position of temporal brokerage have implications that go beyond the boundaries of the focal team, spilling over into other projects the individual is engaged in. Specifically, we predict that being in positions of temporal brokerage on global teams decreases the quantity but increases the quality of an individual’s total productive output. We find support for these predictions across two studies comprising 4,553 individuals participating in global student project teams and 123,586 individuals participating in global academic research teams, respectively. The framework and findings presented in this paper contribute to theories of global teamwork, pivotal roles and leadership emergence in global teams, and social network theory

Sealed Computation: Abstract Requirements for Mechanisms to Support Trustworthy Cloud Computing

In cloud computing, data processing is delegated to a remote party for efficiency and flexibility reasons. A practical user requirement usually is that the confidentiality and integrity of data processing needs to be protected. In the common scenarios of cloud computing today, this can only be achieved by assuming that the remote party does not in any form act maliciously. In this paper, we propose an approach that avoids having to trust a single entity. Our approach is based on two concepts: (1) the technical abstraction of sealed computation, i.e., a technical mechanism to confine the processing of data within a tamper-proof hardware container, and (2) the additional role of an auditing party that itself cannot add functionality to the system but is able to check whether the system (including the mechanism for sealed computation) works as expected. We discuss the abstract technical and procedural requirements of these concepts and explain how they can be applied in practice

The performance of thermal control coatings on LDEF and implications to future spacecraft

The stability of thermal control coatings over the lifetime of a satellite or space platform is crucial to the success of the mission. With the increasing size, complexity, and duration of future missions, the stability of these materials becomes even more important. The Long Duration Exposure Facility (LDEF) offered an excellent testbed to study the stability and interaction of thermal control coatings in the low-Earth orbit (LEO) space environment. Several experiments on LDEF exposed thermal control coatings to the space environment. This paper provides an overview of the different materials flown and their stability during the extended LDEF mission. The exposure conditions, exposure environment, and measurements of materials properties (both in-space and postflight) are described. The relevance of the results and the implications to the design and operation of future space vehicles are also discussed

Trend analysis of in-situ spectral reflectance data from the Thermal Control Surfaces Experiment (TCSE)

The Thermal Control Surfaces Experiment (TCSE) on the LDEF was a comprehensive experiment that combined in-space measurements with extensive pre- and post-flight analyses of thermal control surfaces to determine the effects of exposure to the low earth orbit (LEO) space environment. The TCSE is the first space experiment to directly measure in-situ total hemispherical reflectance of thermal control surfaces in the same way they are routinely measured in the laboratory. In-space optical measurements performed by the TCSE provide the unique opportunity for trend analysis of the performance of materials in the space environment. Such trend analysis of flight data offers the potential to develop an empirical life time prediction model for several thermal control surfaces. For material research, trend analysis of the TCSE flight data, particularly the spectral data, can provide insight into the damage mechanisms of space exposure. Trend analysis for the TCSE samples has been limited to those materials that were not significantly eroded by the atomic oxygen (AO) environment. The performance of several materials on the LDEF mission was dominated by AO effects. Trend analysis was performed on both the detailed spectral reflectance measurements (in-space, pre-flight, and post-flight) and on the integrated solar absorptance. Results of this analysis for the five selected TCSE materials are presented along with the spectral flight data. Possible degradation and effects mechanisms will be discussed to better understand and predict the behavior of these materials in the LEO space environment