Interpretation of the relationship between skin temperature and vegetation fraction: Effect of subpixel soil temperature variability

Both land surface/skin temperature and vegetation indices data provided routinely and globally by NASA MODIS sensors at 1‐km grid resolution represent an important piece of information assimilated into various environmental applications/models. Previous studies based on these and similar remotely data sets and on two‐component pixel representation (accounting for pixel‐aggregated vegetation and bare soil temperatures only) have shown a rather strong linear relationship between the pixel's skin temperature and the vegetation index/fraction. Deviations (Δ₀) from this relationship are frequently used for soil moisture content estimates at a pixel scale. As the two‐component pixel model does not account for subpixel heterogeneity (associated, for example, with bare soil temperature variability within the pixel), its role in controlling a magnitude of Δ₀ has been examined. A simple tri‐component pixel model describing vegetation and wet and dry bare soil temperatures was suggested to analyse an impact of this heterogeneity on Δ₀ estimates. This model was considered to provide a ‘true’ estimate of Δ₀ as compared with Δ₀ evaluated from the two‐component pixel model. A comparison between the models shows that a substantial underestimation of Δ₀ was likely to occur at a level of individual pixels when the two‐component approach was applied for interpretation of the observed relationship between the skin temperature and the vegetation index. Depending on the fraction of pixel occupied by the dry soil, this underestimation might be as much as 100%.     

Thermal management in vertical-external-cavity surface-emitting lasers: finite-element analysis of a heatspreader approach

The use of crystalline heatspreaders to improve thermal management in optically pumped vertical-external-cavity surface-emitting lasers is studied via finite-element analysis. The required properties of a heatspreader are examined and the effect on heat flow is discussed, as are thermal lensing effects. The advantages of diamond heatspreaders are highlighted. The power-scaling potential is compared to other approaches. Heatspreaders are found to be promising, particularly for use with low thermal conductivity semiconductors.     

High Horsepower and High Torque Performance of EP Gear Lubricants

In recent months a series of premature gear failures in field operated vehicles produced indications of insufficient load carrying qualities in extreme pressure lubricants of the GL-4 specification conforming to the new Military L-2105A. This condition prompted dynamometer testing in an investigation of horsepower absorption and high torque absorption of these lubricants as compared with extreme pressure lubricants conforming to Military L-2105 specifications.

The results of the dynamometer testing showed that lubricants conforming to the new Military L-2105A were capable of withstanding continuous high horsepower applications where relatively low torque was required, but were not able to compare favorably with the extreme pressure lubricants of the Military L-2105A specification in regard to continuous high torque applications. The gear-tooth surfaces on such tests with lubricants conforming to the new Military L-2105A were severely scored, whereas the Military L-2105A lubricants produced a satisfactory tooth condition under identical testing conditions.     

Evolving and combining facial composites: Between-witness and within-witness morphs compared.

Student participant-witnesses produced 4 composites of unfamiliar faces with a system that uses a genetic algorithm to evolve appearance of artificial faces. Morphs of 4 composites produced by different witnesses (between-witness morphs) were judged better likenesses (Experiment 1) and were more frequently named (Experiment 2) by participants who were familiar with the target actors than were morphs of 4 composites produced by a single witness (within-witness morphs). Within-witness morphs were judged better likenesses and more frequently named than the best or the first-produced individual composites. The same results for likeness judgments were observed after possible artifacts in the comparison of between- and within-witness morphs were eliminated (Experiment 3). Experiment 4 showed that both internal and external features were better represented in morphs than in the original composites, although the representation of internal features improved more. The results suggest that morphing improves the representation of faces by reducing random error. Between-witness morphs yield more benefit than within-witness morphs by reducing consistent but idiosyncratic errors of individual witnesses. The experiments provide the first demonstration of an advantage for within-witness morphs produced using a single system. Experiment 2 provides the first demonstration of a reliable advantage for between-witness morphs in the most forensically relevant task: naming a composite of a familiar person produced by a witness who was unfamiliar with the target. Morphing would enhance the recognition of facial composites of criminals. Within-witness morphing provides a methodology for use in crimes in which the victim is the only witness. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Canada’s constitutional separation of (wind) power

This paper investigates the impact that a federal government structure has on strategic selection of renewable energy policy instruments. The context for this study centers on wind power development in Canada. Canada is a nation that is blessed by all the attributes necessary to catalyze global leadership in installed wind power capacity. Unfortunately, the constitutional separation of powers that underpins Canada’s federal system impedes the creation of a national wind power development strategy because Canada’s provinces have constitutional authority over electricity governance. The insights gleaned from the case study are used to develop a conceptual framework for understanding the impact that federal structure has on policy instrument selection and efficacy under areas of federal, regional and concurrent policy jurisdiction. Finally, this framework is re-applied to identify specific approaches the Canadian federal government could take to resolve what currently amounts to be a fragmented, ineffective approach to wind power development planning.     

Contrast In Electron Micrographs of Biological Specimens

The information that can be obtained about a biological specimen from the contrast of its image in the electron microscope is discussed. The various methods of treating specimens to increase contrast are mentioned together with the possibility of using contrast measurements to weight and analyse virus particles.     

The socio-political economy of nuclear energy in China and India

This article investigates forms of social, political, and economic organization conducive to nuclear power expansion. We begin by developing a theoretical framework of nuclear socio-political economy based primarily upon the evolution of nuclear energy in France. This framework posits that (1) strong state involvement in guiding economic development, (2) centralization of national energy planning, (3) campaigns to link technological progress to a national revitalization, (4) influence of technocratic ideology on policy decisions, (5) subordination of challenges to political authority, and (6) low levels of civic activism are influential factors in supporting development of nuclear power. Accordingly, we seek to verify the causal properties of these six catalysts for nuclear power expansion in two nations – India and China – that are on the brink of becoming major nuclear powers. We validate our framework by confirming the presence of the six catalysts during the initial nuclear power developmental periods in each country. We also apply our framework as a predictive tool by considering how present conditions in the two nations will impact nuclear power development trends. We conclude by highlighting the emergence of a potential seventh catalyst – the influence of greenhouse gas emission abatement policy on nuclear power development.     

Non‐Invasive High‐Throughput Metrology of Functionalized Graphene Sheets

The utilization of fluorescence quenching microscopy (FQM) for quick visualization of chemical functionalization in relatively large regions of graphene, grown via chemical vapor deposition (CVD), is discussed. Through reactive ion plasma etching, patterns of p‐type CVD‐grown graphene functionalized with fluorine are generated. 4‐(dicyanomethylene)‐2‐methyl‐6‐(4‐dimethylaminostyryl)‐4H‐pyran (DCM) is used as the fluorescent agent. The emission of DCM is quenched to a different extent by fluorinated and pristine graphene, which provides the fluorescence‐imaging contrast essential for this metrology. To probe the functionalized surface patterns with DCM, the dye is dispersed in polymethylmethacrylate (PMMA) then the graphene surface is coated, forming a 30‐nm‐thick DCM‐PMMA layer. Fluorescence images of dye‐coated graphene distinctly reveal the difference between the chemically treated and as‐grown regions. The pristine graphene quenches the DCM emission more efficiently than the fluorinated graphene. Therefore, the regions with pristine graphene appear darker on the fluorescence images than the regions with fluorinated graphene, enabling large‐scale mapping of the functionalized regions in CVD grown graphene sheets Due to its simplicity and consistent results, FQM is now poised for widespread adoption by graphene manufacturers as a basis for facile and high throughput metrology of large‐scale graphene sheets.     

PIV as a method for quantifying root cell growth and particle displacement in confocal images

Particle image velocimetry (PIV) quantifies displacement of patches of pixels between successive images. We evaluated PIV as a tool for microscopists by measuring displacements of cells and of a surrounding granular medium in confocal laser scanning microscopy images of Arabidopsis thaliana roots labeled with cell‐membrane targeted green fluorescent protein. Excellent accuracy (e.g., displacement standard deviation <0.006 pixels) was obtained for root images that had undergone rigid digital translations of up to 40 pixels. Analysis of zoomed images showed that magnifications of up to 5% maintained good linear relations between PIV‐predicted and actual displacements (r² > 0.83). Root mean squared error for these distorted images was 0.4–1.1 pixels, increasing at higher magnification factors. Cell growth and rhizosphere deformation were tracked with good temporal (e.g., 1‐min interval) and spatial resolution, with PIV patches located on recognizable cell features being tracked more successfully. Appropriate choice of GFP‐label was important to decrease small‐scale biological noise due to intracellular motion. PIV of roots grown in stiff 2% versus 0.7% agar showed patterns of cell expansion consistent with physically impeded roots of other species. Roots in glass ballotini underwent rapid changes in growth direction on a timescale of minutes, associated with localized arching of ballotini. By tracking cell vertices, we monitored automatically cell length, width, and area every minute for 0.5 h for cells in different stages of development. In conclusion, PIV measured displacements successfully in images of living root cells and the external granular medium, revealing much potential for use by microscopists. Microsc. Res. Tech., 2009. © 2009 Wiley‐Liss, Inc.