Continuum removed band depth analysis for detecting the effects of natural gas, methane and ethane on maize reflectance

It is known that natural gas in the soil affects vegetation health, which may be detected through analysis of reflectance spectra. Since natural gas is invisible, changes in the vegetation could potentially indicate gas leakage. Although it is known that gas in soil affects plant reflectance, the relationship between natural gas and the development and reflectance properties of plants has not been studied. The objective of this study was to test whether natural gas and its two main components, methane and ethane, affect vegetation reflectance in the chlorophyll and water absorption regions. An experiment was carried out in which maize (Zea mays) plants were grown in pots that were flushed with 10 l of gas per day for 39 ±4 days. Leaf reflectance was measured once a week with a spectrophotometer. The reflectance was analysed using continuum removal of the blue (400-550 nm), red (550-750 nm) and two water absorption features (1370-1570 nm and 1870-2170 nm), after which the band depths and normalized band depths were analyzed for each treatment. The band depth analysis showed that ethane caused an initial increase of 10% in reflectance between 560 and 590 nm, followed by a decrease during the course of the experiment. Normalized band depth analysis showed that ethane caused a reflectance shift of 1 to 5 nm towards longer wavelengths compared to the control reflectance in the visible region. All gases caused an increase in reflectance in the water absorption bands. The physiological reflectance index, PRI, which has previously linked water stress to photosynthetic activity, suggested that the hydrocarbon gases (particularly ethane) decreased the photosynthetic activity of the plants.The combination of reduced band depths in the chlorophyll and water absorption regions and the increased PRI suggests that ethane gas in the soil hampered a normal water uptake by maize plants in an early stage of their growth. Although further research is necessary to upscale the results from the laboratory to the field, the increased reflectance in the 560-590 nm region caused by ethane together with the increased PRI are promising indicators for gas leakage.     

Die eGK-L?sungsarchitektur Architektur zur Unterstützung der Anwendungen der elektronischen Gesundheitskarte

Mit der für 2006 vorgesehenen Einführung der elektronischen Gesundheitskarte für alle gesetzlich und privat Krankenversicherten werden bislang vorwiegend in Papierform vorliegende Daten – wie z.B. Rezepte, überweisungen und Patientenakten – elektronisch verfügbar gemacht.     

Tri-n-butyltin hydride reduction of the end group of a polyphenylene ether

Summary A method using tri-n-butyltin hydride to reduce the 2-methyl-6-(N,N-di-n-butylamino)methyl phenol end group on PPO^®(4) was developed. It generated a polyphenylene ether (PPE) with 2,6-xylenol as the only phenolic end group without causing any significant increase in molecular weight.     

What We Know About Learning*

Traditionally, engineering research and teaching have been approached in very different ways. To prepare for research we undergo years of rigorous training, both in scientific knowledge and in methods of gaining new knowledge through experimentation and analysis. To prepare for teaching, we acquire the same knowledge, but, except for a stint as a teaching assistant, we receive almost no training in how to impart it to students. Fortunately, there is now a well developed science of human learning which has strong implications for the ways in which our students should learn and we should teach. This paper comments on some of the things we know about human learning that can substantially improve our university instruction.     

An overview of MiMo2

The MiMo2 translation system combines several leading ideas in the areas of linguistics, computation and translation. In the area of translation we follow the ideas of Landsbergen (1987) by assuming that translation is symmetric; and combine these ideas with the advantages of a transfer approach. Computationally the system focuses on computability and declarativity. The linguistics of the system is based on a lexicalistic and sign-based approach to grammar.MiMo2 is a sideline project of the Dutch Eurotra team in Utrecht. An extended version of this article was presented at the machine translation workshop in Austin, Texas, June 1990.     

Interleukin-2-induces development of denditric cells from cord blood CD34+ cells

Fiducial markers are reference points used in the registration of image space(s) with physical (patient) space. As applied to interactive, image-guided surgery, the registration of image space with physical space allows the current location of a surgical tool to be indicated on a computer display of patient-specific preoperative images. This intrasurgical guidance information is particularly valuable in surgery within the brain, where visual feedback is limited. The accuracy of the mapping between physical and image space depends upon the accuracy with which the fiducial markers were located in each coordinate system. To effect accurate space registration for interactive, image-guided neurosurgery, the use of permanent fiducial markers implanted into the surface of the skull is proposed in this paper. These small cylindrical markers are composed of materials that make them visible in the image sets. The challenge lies in locating the subcutaneous markers in physical space. This paper presents an ultrasonic technique for transcutaneously detecting the location of these markers. The technique incorporates an algorithm based on detection of characteristic properties of the reflected A-mode ultrasonic waveform. The results demonstrate that ultrasound is an appropriate technique for accurate transcutaneous marker localization. The companion paper to this article describes an automatic, enhanced implementation of the marker-localization theory described in this article.     

Mindestantriebsmoment zur Resonanzdurchfahrt von unwuchtigen elastischen Rotoren

Zusammenfassung In der vorliegenden Arbeit wir das für die Resonanzdurchfahrt notwendige Mindestantriebsmoment der mit einer Scheibe besetzten biegeelastischen Welle (Laval-L?ufer) untersucht Der Einflu? der inneren und ?u?eren D?mpfung, der Unrundheit der Welle und des Gewichtes wird dabei berücksichtigt. Zwei Methoden werden zur Untersuchung des Problems angewendet: das Verfahren von Kononenko und die Str?rungsrechnung. Die Resultate der beiden Berechnungswege werden verglichen.     

The ageing of a BaTiO3 dielectric containing both ferroelectric and paraelectric components

A BaTiO₃ composition with a high ageing rate of permittivity and demonstrating a downward bend in its permittivity versus log time characteristic is studied. Models which assume ageing and non-ageing components in series or series/parallel configurations reproduce the characteristic and indicate an initial permittivity exceeding 5000 for the ageing component at a temperature 40 K below its Curie point.     

Diffusion layer interpretation of the interaction of electrorefining addition agents

The roles of various addition agents in commercial electrorefining electrolytes were studied by means of 190 potentiostatic scans. The role of each addition agent and their interactions with one another were clarified. The protein material caused increased polarization at low current densities, presumably by adsorbing on the cathode growth sites. The effect of protein additions was strongly affected by the presence of other addition agents. All the addition agents in small concentrations including the protein tend to increase limiting current density. A model of increased diffusion due to disruption of the diffusion layer by addition agents is consistent with the data.