Effect of oxidants on microalgal flocculation

The effects of chlorine, ozone and chlorine dioxide on Scenedesmus sp. cultures were studied. Algal cell viability and chlorophyll concentration decreased, and the concentration of dissolved organic substances increased with increasing applied oxidant concentration. Pretreatment with chlorine dioxide (1, 3 or 5 mg l⁻¹) or ozone (2.6, 4.6 or 8.1 mg l⁻¹) on algal cultures enhanced algal flocculation with alum, while prechlorination with 10 or 20 mg l⁻¹ increased the required dosage of alum by 15%. Scanning electron micrographs of oxidized cells revealed drastically adverse effects upon the cell surface architecture: in addition to the oxidation of noncellular organic materials, the oxidants damaged both cell surface structures and intracellular components. A model explaining the effects of the different oxidants on microalgal flocculation is suggested.     

Fast GL(n)-Invariant Framework for Tensors Regularization

We propose a novel framework for regularization of symmetric positive-definite (SPD) tensors (e.g., diffusion tensors). This framework is based on a local differential geometric approach. The manifold of symmetric positive-definite (SPD) matrices, P _n , is parameterized via the Iwasawa coordinate system. In this framework distances on P _n are measured in terms of a natural GL(n)-invariant metric. Via the mathematical concept of fiber bundles, we describe the tensor-valued image as a section where the metric over the section is induced by the metric over P _n . Then, a functional over the sections accompanied by a suitable data fitting term is defined. The variation of this functional with respect to the Iwasawa coordinates leads to a set of \frac12n(n+1)\frac{1}{2}n(n+1) coupled equations of motion. By means of the gradient descent method, these equations of motion define a Beltrami flow over P _n . It turns out that the local coordinate approach via the Iwasawa coordinate system results in very simple numerics that leads to fast convergence of the algorithm. Regularization results as well as results of fibers tractography for DTI are presented.     

Flexible Blade‐Coated Multicolor Polymer Light‐Emitting Diodes for Optoelectronic Sensors

A method to print two materials of different functionality during the same printing step is presented. In printed electronics, devices are built layer by layer and conventionally only one type of material is deposited in one pass. Here, the challenges involving printing of two emissive materials to form polymer light‐emitting diodes (PLEDs) that emit light of different wavelengths without any significant changes in the device characteristics are described. The surface‐energy‐patterning technique is utilized to print materials in regions of interest. This technique proves beneficial in reducing the amount of ink used during blade coating and improving the reproducibility of printed films. A variety of colors (green, red, and near‐infrared) are demonstrated and characterized. This is the first known attempt to print multiple materials by blade coating. These devices are further used in conjunction with a commercially available photodiode to perform blood oxygenation measurements on the wrist, where common accessories are worn. Prior to actual application, the threshold conditions for each color are discussed, in order to acquire a stable and reproducible photoplethysmogram (PPG) signal. Finally, based on the conditions, PPG and oxygenation measurements are successfully performed on the wrist with green and red PLEDs.     

Harnessing “Click”‐Type Chemistry for the Preparation of Novel Electronic Materials

Sequence‐independent or “click”‐type chemistry is applied for the preparation of novel π‐conjugated oligomers. A variety of bi‐functional monomers for Wittig–Horner olefination are developed and applied in a sequential protection–deprotection process for the preparation of structurally similar π‐conjugated oligomers. Selected oligomers are incorporated as the organic semiconductors in light‐emitting diodes and a field‐effect transistor, demonstrating the potential of the approach.     

The Explanatory Role of Computation in Cognitive Science

Which notion of computation (if any) is essential for explaining cognition? Five answers to this question are discussed in the paper. (1) The classicist answer: symbolic (digital) computation is required for explaining cognition; (2) The broad digital computationalist answer: digital computation broadly construed is required for explaining cognition; (3) The connectionist answer: sub-symbolic computation is required for explaining cognition; (4) The computational neuroscientist answer: neural computation (that, strictly, is neither digital nor analogue) is required for explaining cognition; (5) The extreme dynamicist answer: computation is not required for explaining cognition. The first four answers are only accurate to a first approximation. But the ??devil?? is in the details. The last answer cashes in on the parenthetical ??if any?? in the question above. The classicist argues that cognition is symbolic computation. But digital computationalism need not be equated with classicism. Indeed, computationalism can, in principle, range from digital (and analogue) computationalism through (the weaker thesis of) generic computationalism to (the even weaker thesis of) digital (or analogue) pancomputationalism. Connectionism, which has traditionally been criticised by classicists for being non-computational, can be plausibly construed as being either analogue or digital computationalism (depending on the type of connectionist networks used). Computational neuroscience invokes the notion of neural computation that may (possibly) be interpreted as a sui generis type of computation. The extreme dynamicist argues that the time has come for a post-computational cognitive science. This paper is an attempt to shed some light on this debate by examining various conceptions and misconceptions of (particularly digital) computation.     

Threshold of stimulated Brillouin scattering by use of a solar pumped laser

What is to our knowledge the first stimulated Brillouin scattering experiment using a high-power low-gain solar pumped laser is presented. A threshold reflectivity of 0.23% was reached when a peak power of 20.7 kW was used at 7.6 GHz. A cw solar pumped laser was Q-switched with an acousto-optic modulator, and the bandwidth was narrowed with an intracavity etalon. A high polarization ratio (>99.4%) was achieved by use of an intracavity configuration. Higher reflectivity values were limited because of the lack of availability of optical switches.     

Interface Modifications of InAs Quantum‐Dots Solids and their Effects on FET Performance

InAs nanocrystals field‐effect transistors with an ON/OFF ratio of 10⁵ are reported. By tailoring the interface regions in the active layer step‐by‐step, the evolution of the ON/OFF ratio can be followed from approximately 5 all the way to around 10⁵. The formation of a semiconducting solid from colloidal nanocrystals is achieved through targeted design of the nanocrystal–nanocrystal interaction. The manipulation characteristics of the nanocrystal interfaces include the matrix surrounding the inorganic core, the interparticle distance, and the order of nanocrystals in the 3D array. Through careful analysis of device characteristics following each treatment, the effect of each on the physical properties of the films are able to be verified. The enhanced performance is related to interparticle spacing, reduction in sub‐gap states, and better electronic order (lower σ parameter). Films with enhanced charge transport qualities retain their quantum‐confined characteristics throughout the procedure, thus making them useful for optoelectronic applications.     

Strategy logic

We introduce strategy logic, a logic that treats strategies in two-player games as explicit first-order objects. The explicit treatment of strategies allows us to specify properties of nonzero-sum games in a simple and natural way. We show that the one-alternation fragment of strategy logic is strong enough to express the existence of Nash equilibria and secure equilibria, and subsumes other logics that were introduced to reason about games, such as ATL, ATL¹, and game logic. We show that strategy logic is decidable, by constructing tree automata that recognize sets of strategies. While for the general logic, our decision procedure is nonelementary, for the simple fragment that is used above we show that the complexity is polynomial in the size of the game graph and optimal in the size of the formula (ranging from polynomial to 2EXPTIME depending on the form of the formula).