Reconstructing vectorised photographic images

We address the problem of representing captured images in the continuous mathematical space more usually associated with certain forms of drawn ('vector') images. Such an image is resolution-independent so can be used as a master for varying resolution-specific formats. We briefly describe the main features of a vectorising codec for photographic images, whose significance is that drawing programs can access images and image components as first-class vector objects. This paper focuses on the problem of rendering from the isochromic contour form of a vectorised image and demonstrates a new fill algorithm which could also be used in drawing generally. The fill method is described in terms of level set diffusion equations for clarity. Finally we show that image warping is both simplified and enhanced in this form and that we can demonstrate real histogram equalisation with genuinely rectangular histograms

Autonomous model protocell division driven by molecular replication

The coupling of compartmentalisation with molecular replication is thought to be crucial for the emergence of the first evolvable chemical systems. Minimal artificial replicators have been designed based on molecular recognition, inspired by the template copying of DNA, but none yet have been coupled to compartmentalisation. Here, we present an oil-in-water droplet system comprising an amphiphilic imine dissolved in chloroform that catalyses its own formation by bringing together a hydrophilic and a hydrophobic precursor, which leads to repeated droplet division. We demonstrate that the presence of the amphiphilic replicator, by lowering the interfacial tension between droplets of the reaction mixture and the aqueous phase, causes them to divide. Periodic sampling by a droplet-robot demonstrates that the extent of fission is increased as the reaction progresses, producing more compartments with increased self-replication. This bridges a divide, showing how replication at the molecular level can be used to drive macroscale droplet fission

Complementary epistemologies of science teaching: Towards an integral perspective

For over two decades, science education has been a site of struggle between adherents of the apparently antithetical epistemologies of objectivism and constructivism; recently, proponents of personal and social constructivism have locked horns. However, at the beginning of the 21st Century, we feel that it is timely for science education to enter an age of pluralism, of tolerance for multiple and competing ways of knowing, in which no one way is ultimately privileged; to exercise humility about the authority of our cherished ways of knowing the world around us. In the interest of creating greater equity of access amongst students to a much richer encounter with science, a new mode of pedagogical reasoning is needed. From the perspective of constructive postmodernism, we propose dialectical thinking as a way of generating unity-in- diversity, and metaphor as a key referent for overcoming the obstacle of literalism which tends to reinforce fundamentalist notions of difference. We illustrate the viability of an integral perspective on science teaching with a brief account of an inquiry into the scientific literacy of a class of junior high school students, from which emerged a 3-metaphor framework. Mindful of the limitations of this framework, we argue for science education researchers to join us in conceptualizing more powerful and compelling integral metaphors for promoting worldwide epistemological pluralism and cultural diversity

Study of the Local Interstellar Medium using Pulsar Scintillation

We present here the results from an extensive scintillation study of twenty pulsars in the dispersion measure (DM) range 3 - 35 pc cm^-3 carried out using the Ooty Radio Telescope, to investigate the distribution of ionized material in the local interstellar medium (LISM). Our analysis reveals several anomalies in the scattering strength, which suggest that the distribution of scattering material in the Solar neighborhood is not uniform. Our model suggests the presence of a low density bubble surrounded by a shell of much higher density fluctuations. We are able to put some constraints on geometrical and scattering properties of such a structure, and find it to be morphologically similar to the Local Bubble known from other studies.Comment: 5 pages, 3 figure

Ultraviolet Complete Electroweak Model Without a Higgs Particle

An electroweak model with running coupling constants described by an energy dependent entire function is utraviolet complete and avoids unitarity violations for energies above 1 TeV. The action contains no physical scalar fields and no Higgs particle and the physical electroweak model fields are local and satisfy microcausality. The $W$ and $Z$ masses are compatible with a symmetry breaking $SU(2)_L\times U(1)_Y \rightarrow U(1)_{\rm em}$, which retains a massless photon. The vertex couplings possess an energy scale $\Lambda_W > 1$ TeV predicting scattering amplitudes that can be tested at the LHC.Comment: 19 pages, no figures, LaTex file. Equation and text corrected. Reference added. Results remain the same. Final version published in European Physics Journal Plus, 126 (2011

Quantum dot emission from site-controlled ngan/gan micropyramid arrays

InxGa1−xN quantum dots have been fabricated by the selective growth of GaN micropyramid arrays topped with InGaN/GaN quantum wells. The spatially, spectrally, and time-resolved emission properties of these structures were measured using cathodoluminescence hyperspectral imaging and low-temperature microphotoluminescence spectroscopy. The presence of InGaN quantum dots was confirmed directly by the observation of sharp peaks in the emission spectrum at the pyramid apices. These luminescence peaks exhibit decay lifetimes of approximately 0.5 ns, with linewidths down to 650 me

Efficacy, persistence, ground deposition, and human exposure of polymer-encapsulated lindane and chlorpyrifos used for control of the southern pine beetle

Des applications de lindane et de chlorpyrifos ont été étudiées pour déterminer si l'encapsulation dans un polymère augmente la répression du dendroctone méridional du pin (Dendroctonusfrontalis), diminue l'étendue des retombées, augmente la durée d'adhésion à l'écorce ou réduit les contacts humains, en comparaison avec des applications de concentrés émulsifiés.L'encapsulation n'augmente pas l'efficacité et ne réduit pas les retombées des insecticides par rapport aux applications émulsifiées normales. L'encapsulation du chlorpyrifos augmente la persistance résiduelle mais n'affecte pas la persistance du lindane. Le risque de contact humain avec l'écorce encore humidifiée par le chlorpyrifos encapsulé est 2,2 fois plus élevé tandis que le risque de contact du lindane n'est pas influencé par l'encapsulation. Cependant, une fois l'insecticide séché, les applications encapsulées réduisent le risque de contact humain de 90% pour le lindane et de 83% pour le chlorpyrifos.Formulations of lindane and chlorpyrifos were evaluated to determine if polymer encapsulation extended the duration of southern pine beetle (Dendroctonusfrontalis) control, reduced ground deposition, increased persistence on bark or reduced potential human exposure relative to emulsifiable concentrate formulations. Encapsulation did not extend efficacy or reduce ground deposition of either insecticide when compared with the standard emulsifiable formulations. Encapsulation extended residue persistence of chlorpyrifos on bark, but not of lindane. The potential risk of human exposure to bark which was still wet with chlorpyrifos was increased 2.2 times by encapsulation, whereas, similar exposure to lindane was unaffected by encapsulation. After the insecticides had dried on the bark, the encapsulated formulations reduced risk to lindane by approximately 90% and by 83 % for chlorpyrifos