Polarized light imaging of white matter architecture

Polarized light imaging (PLI) is a method to image fiber orientation in gross histological brain sections based on the birefringent properties of the myelin sheaths. The method uses the transmission of polarized light to quantitatively estimate the fiber orientation and inclination angles at every point of the imaged section. Multiple sections can be assembled into a 3D volume, from which the 3D extent of fiber tracts can be extracted. This article describes the physical principles of PLI and describes two major applications of the method: the imaging of white matter orientation of the rat brain and the generation of fiber orientation maps of the human brain in white and gray matter. The strengths and weaknesses of the method are set out.     

From concepts to consistent object specifications: Translation of a domain-oriented feature framework into practice

A steady increase in consumer demands,and severe constraints from both a somewhat damaged environment and newly installed government policies,require today‘s product design and development to be faster and more efficient than ever before,yet utilizing even fewer resources.New holistic approaches,such at total product life cycle modeling which embraces all aspercts of a product‘s life cycle,are current attempts to solve these problems,Within the field of product design and modeling,feature technology has proved to be one very promising solution component.Owing to the tremendous increase in information technology,to transfer from low level data processing towards knowledge modeling and information processing is about to bring a change in almost every computerized application.From this viewpoint,current problems of both feature frameworks and feature systems are analyzed in respect to static and dynamic consistency breakdowns.The analysis ranges from early stager of designing(feature)concepts to final system implementation and application.For the first tie,an integrated view is given on approaches,solutions and practical experience,with feature concepts and structures,providing both a feature framework and its implementation with sufficient system architecture and computational power to master a fair number of known consistency breakdowns,while providing for robust contexts for feature semantics and integrated models.Within today;s heavy use of information technology these are pre-requisites if the full potential of feature technology is to be successfully translated into practice.     

Low-cost telepresence for collaborative virtual environments

We present a novel low-cost method for visual communication and telepresence in a CAVEtrade-like environment, relying on 2D stereo-based video avatars. The system combines a selection of proven efficient algorithms and approximations in a unique way, resulting in a convincing stereoscopic real-time representation of a remote user acquired in a spatially immersive display. The system was designed to extend existing projection systems with acquisition capabilities requiring minimal hardware modifications and cost. The system uses infrared-based image segmentation to enable concurrent acquisition and projection in an immersive environment without a static background. The system consists of two color cameras and two additional b/w cameras used for segmentation in the near-IR spectrum. There is no need for special optics as the mask and color image are merged using image-warping based on a depth estimation. The resulting stereo image stream is compressed, streamed across a network, and displayed as a frame-sequential stereo texture on a billboard in the remote virtual environment     

A note on thue systems with a single defining relation

A combinatorial characterization is given for those one-rule Thue systems of the form {(w ₁,w ₂)} with 0 |w ₂||ov(w ₁)| that are Church-Rosser. Here ov(w ₁) denotes the longest proper self-overlap ofw ₁. Further, it is shown that a Thue system of this form is Church-Rosser if and only if there is an equivalent Thue system that is Church-Rosser.This research was supported in part by the National Science Foundation under Grant No. MCS83-14977. It was performed while the first author was visiting the Department of Mathematics of the University of California at Santa Barbara.     

Der besondere L?sungszustand von Caseinatschmelzen

Zusammenfassung Eine mit Schmelzsalz hergestellte Caseinschmelze hat Eigenschaften, die mit einer Lösung von Casein in Wasser nicht vereinbar sind. Das spezifische Partialvolumen des Wassers ist gegenüber reinem Wasser deutlich vergrößert. Die Aktivität des Schmelzwassersa _W ist > 1 statt < 1. Die Anomalien werden durch einen Solzustand erklärt, der mit einer umgekehrten Lösung vergleichbar ist. Das bedeutet, daß in der Schmelze unter dem Einfluß der Schmelzsalze das Wasser vom Casein aufgenommen wird. Wasser wird nun zum gelösten Stoff, dessen Kohäsionskräfte herabgesetzt sind. Die Folge ist eine Vergrößerung des Partialvolumens und eine erhöhte Wasseraktivität.

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The particular solution state of processed casein

Summary Processed casein manufactured with melting salts has properties which are not consistent with a solution of casein in water. The specific partial volume of the water is clearly encreased compared with pure water . The activity of the watera _W is > 1 instead of < 1. The irregularities are explained by a solution state which is comparable to an inverted solution. That means that by melting salts in the melt water is absorbed from casein. Water now becomes the solute, whose cohesive forces are decreased. The result is an increase of the partial volume and a higher water activity.

     

The molecular structure of asphaltene: an unfolding story

From detailed chemical and thermal degradation studies, a host of structural units have been identified in Alberta asphaltenes. It has been shown that the extent of aromatic condensation is low and that highly condensed pericyclic aromatic structures are present in very low concentrations. From the available data reported to date, it is concluded that petroleum asphaltenes were mainly derived through the catalytic cyclization, aromatization and condensation of n-alkanoic, probably fatty acids, precursors.     

Microstructure Development of Oxycarbide Composites during Active-Filler-Controlled Polymer Pyrolysis

The microstructure development of a ceramic composite material fabricated by active-filler-controlled polymer pyrolysis (AFCOP) was investigated. During heating of a polysiloxane precursor mixed with titanium powder in argon atmosphere up to 1400°C, thermally induced decomposition of the polymer phase is combined with simultaneous carburization of the transition metal filler. Precipitation of nanocrystalline titanium carbide at the filler particle surface starts above 400°C, and larger, faceted carbide particles have growth above 800°C. A skeleton of turbostratic carbon is formed above 800°C in the polymer-derived silicon oxycarbide matrix from which b-silicon carbide and cristobalite crystallize above 1000°C. A pronounced reduction in linear shrinkage involved in polymer–ceramic conversion is observed. The shrinkage reduction ranges from more than 25% for the filler-free precursor to less than 10% in the presence of 30 vol% of the titanium filler. Thus, active-filler-controlled pyrolysis offers the possibility of controlling shrinkage and porosity formation during polymer–ceramic conversion in order to fabricate bulk components from organometallic polymer precursor systems.     

Executive Summary—Community Water Supply: The Handpump Option

An estimated 1,800 million people need improved water supplies in the fifteen years to the end of the century, if developing countries are to reach the target of full coverage. The first half of the International Drinking Water Supply and Sanitation Decade (1981–1990) has seen increases in the percentages of the rural population with access to safe water supplies, but only in Asia has the pace been quick enough to envisage a target of essentiahy full coverage by the end of the century (ten years later than the original Decade goals). In Africa, present progress rates would leave half of the rural population still without safe water in the year 2000, while in Latin America, it may be ten years into the next century before full coverage is achieved unless progress improves dramatically.

Accelerated progress is hampered by financial and technical resource constraints faced by many developing countries, and the problem is aggravated by the growing number of completed projects which are broken down and abandoned, or functioning much below capacity. Attempts to increase the pace of providing improved community water supplies have often been frustrated because the technology used has proved impossible to sustain in village conditions.

To make a lasting impact on the urgent needs, community water supply (CWS) strategies must be based on sustainable and replicable programs, and must take account of the pace at which resource constraints can be overcome. Human resource development programs take time to produce results, and institutional changes can only be accomplished gradually.     

Time-of-flight sensor and color camera calibration for multi-view acquisition

This paper presents a multi-view acquisition system using multi-modal sensors, composed of time-of-flight (ToF) range sensors and color cameras. Our system captures the multiple pairs of color images and depth maps at multiple viewing directions. In order to ensure the acceptable accuracy of measurements, we compensate errors in sensor measurement and calibrate multi-modal devices. Upon manifold experiments and extensive analysis, we identify the major sources of systematic error in sensor measurement and construct an error model for compensation. As a result, we provide a practical solution for the real-time error compensation of depth measurement. Moreover, we implement the calibration scheme for multi-modal devices, unifying the spatial coordinate for multi-modal sensors. The main contribution of this work is to present the thorough analysis of systematic error in sensor measurement and therefore provide a reliable methodology for robust error compensation. The proposed system offers a real-time multi-modal sensor calibration method and thereby is applicable for the 3D reconstruction of dynamic scenes.