Multiscale assessment of green leaf cover in a semi-arid rangeland with a small unmanned aerial vehicle

Spatial variability in green leaf cover of a semi-arid rangeland was studied by comparing field measurements on 50 m crossed transects to aerial and satellite imagery. The normalized difference vegetation index was calculated for 2 cm resolution images collected with a multispectral digital camera mounted on a radio-controlled helicopter, as well as a 30 m resolution Landsat Thematic Mapper image. Variograms of green cover from these two sources show that the range of influence for spatial autocorrelation extended to a distance of approximately 200 m. Field transects that are much smaller than the extent of this spatial autocorrelation are more likely to fall within local deviations from the mean landscape condition. A sampling scheme that exceeds the spatial scale of these localized deviations is shown to reduce sample variance and require fewer sampling locations to reach a given level of measurement uncertainty. The time and cost of more spatially extensive sampling at each location may be less than deploying to a larger number of locations with smaller transects, and unmanned aerial vehicles may be a valuable tool in extending current field sampling strategies for quantifying the health of shrub-dominated rangelands.     

Green Nanocomposites of Natural Rubber/ Olivine Nanosilica: Viscoelastic,Mechanical, Transport and Thermal Characterizations

Silicon - Nanosilica was synthesized from a low cost raw material, olivine by a more sustainable and cost effective method. The pure nanosilica obtained was amorphous in nature with a surface area...     

Sensing danger: Innate immunology for intrusion detection

The immune system provides an ideal metaphor for anomaly detection in general and computer securities in particular. Based on this idea, artificial immune systems have been used for a number of years for intrusion detection, unfortunately so far with little success. However, these previous systems were largely based on immunological theory from the 1970s and 1980s and over the last decade our understanding of immunological processes has vastly improved. In this paper we present two new immune-inspired algorithms based on the latest immunological discoveries, such as the behaviour of Dendritic Cells. The resultant algorithms are applied to real-world intrusion problems and show encouraging results. Overall, we believe that there is a bright future for these next-generation artificial immune algorithms.     

Fast in situ 3D nanoimaging: a new tool for dynamic characterization in materials science

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Relationship between microstructure and mechanical properties of polyether block amide foams

The mechanical behaviors of five polyether block amide foams, obtained by mold-opening foam injection process, were investigated with regard to their microstructures. The materials vary in mass ratios of hard versus soft segments, and/or in process packing time. The resulting microstructures have been characterized in terms of cavity size and shape ratios, by analyzing scanning electron microscope images after careful sample preparation. The foam mechanical responses have been characterized in compression at small and large strain. At small strain, the initial linear part of the stress–strain curve is enhanced firstly by the hard segment mass ratio and secondly by the fineness of the microstructure. Similar results have been obtained at large strain. The foam viscoelasticity at large strain has been characterized by stress relaxation and strain recovery tests, relevant for foam applications. Reduced packing time and pressure have been shown to lead to the presence of undesired large cavities. The morphological defects appear to have a negligible impact on the macroscopic mechanical behavior of the foams at infinitesimal strain, but lead to critical inconsistency at large strain. Furthermore, the mechanical behavior of the tested polyether block amide foams is controlled first by hard versus soft segments ratio, and second by the microstructure fineness.     

Abdominal sensory equipment involved in external host discrimination in a solitary parasitoid wasp

Already parasitized hosts are often of poorer quality than healthy hosts. It is therefore usually advantageous for parasitoid females to recognize and reject them. Parasitized hosts can be identified on the basis of various physical or chemical marks present on the surface or inside the hosts or their surroundings in the case of concealed host. Here we studied host discrimination behaviors of females of a certain population of Pachycrepoideus vindemmiae, a solitary ectoparasitoid, which are known to reject large-sized parasitized hosts after an abdominal examination of their surface. We first investigated females' recognition behaviors of host parasitism status when confronted to small-sized hosts (Drosophila melanogaster pupae) as host size may influence the use of different cues for host selection. We showed that, in such a situation, females also discriminate parasitized hosts after an external host exploration with the tip of their ovipositor sheath (third valvulae). We then described the sense organs present on the different parts of the ovipositor by means of scanning and transmission electron microscopy analysis. As the extremity of the third valvulae bears only one type of sensilla that appears to be chemoreceptors, we considered these sensilla as highly likely to be involved in host discrimination in P. vindemmiae. To our knowledge, this is the first time that receptors located on the ovipositor sheath are described as implicated in host discrimination in parasitoid wasps. We discuss potential chemical markers that might be detected by these receptors.     

Partnering effects on user-developer conflict and role ambiguity in information system projects

Context

Information system development (ISD) has been plagued with high failure rates. This is partially due to the activities being a combination of both a technical and social processes involving stakeholders with conflicting interests.

Objective

Existing software risk management theories and frameworks offer limited suggestions for actions that can be taken to reduce the chance of failure of ISD projects. Our objective is to examine the connections among some of the more important user related risks in order to shed light on how specific strategies enhance the chance of project success.

Method

We conducted a sample of information systems project managers to test a multivariate model to explain the impact of pursuing a partnership with users on the conflicts that arise between users and developers, role ambiguity, and subsequent impact on project performance.

Results

The proposed model was supported, suggesting that user-developer conflict and role ambiguity have a negative impact on performance estimation difficulty, which negatively affects project performance.

Conclusion

Pursuit of project partnering yields a number of significant relationships in the model indicating an organization can implement practices that reduce risks associated with role ambiguity and conflict in system development projects.     

Plasma polymer coated surfaces for serum-free culture of limbal epithelium for ocular surface disease

The potential use of plasma polymer coatings as substrates for serum-free expansion of limbal epithelial cells was investigated. Preliminary studies using a human corneal epithelial cell line showed that acrylic acid-coated surfaces performed better than allyl amine and allyl alcohol coated surfaces in terms of cell metabolic activity and confluence as assessed using the MTT assay. Subsequently, the proliferation and maturity of primary human limbal epithelial cells in co-culture with growth arrested 3T3 fibroblasts on a range of acrylic acid plasma coated surfaces, octadiene plasma coated surfaces and tissue culture plastic was investigated using MTT and cytokeratin 3 immunostaining. The cells performed better in the presence of serum on all surfaces. However, the acrylic acid coated surfaces successfully sustained a serum-free fibroblast/epithelial cell co-culture. The metabolic activity of the epithelial cells was superior on the acrylic acid coated surfaces than on tissue culture plastic in serum-free conditions and their levels of differentiation were not significantly higher than in the presence of serum. These results suggest that these surfaces can be used successfully for the serum-free expansion of human limbal epithelial cells.     

Wide Reach of Migratory Bird Treaty Act for Energy Projects

For nearly a century, the Migratory Bird Treaty Act has been a tool used by the federal government to protect migratory bird species.¹