Library

Notes: We study the magnetoresistance (MR) of Py/Py, Co/Py, Co/Co, Ni/Ni, and Co/Cu point contacts (Py=permalloy=Ni80Fe20). These devices are narrow constrictions or channels (diameter, length (approximate)30 nm) between two thin film electrodes. Due to the small size of the constriction, which is comparable to a bulk domain-wall (DW) thickness, a DW can be caught in it. For almost all material combinations studied we find that low resistance contacts show an MR minimum at zero field (H=0) of magnitude 0.4%–1.3%, for temperatures between 1.5 and 293 K. The minimum occurs for all field orientations with respect to the channel axis. When the contact resistance increases beyond the value set by a diameter-to-length ratio for the channel of about unity, the resistance minima at H=0 evolve into a maximum/minimum combination as expected for a predominant anisotropic magnetoresistance (AMR) effect. We use micromagnetic calculations based on magnetostatic and exchange interactions to obtain the magnetization in the constriction. These calculations predict that, due to the finite channel length, there are two partial DWs at either side of the channel. For high resistance contacts this agrees with the observed AMR, which results from scattering in the homogeneously magnetized material in the channel. The MR minimum for low resistance contacts arises from the DWs, which cause a resistance decrease. We attribute this decrease to a change of spin-dependent diffuse scattering at the constriction boundary due to the DWs. © 2001 American Institute of Physics.

Notes: Research into both extraction of man-made objects and automatic change detection from aerial and satellite images has made significant progress in recent years. This paper presents an approach, based on a fuzzy logic system, for the identification of suburban roads in Ikonos images. The linguistic variables are the mean and standard deviation (SD) of different objects with Gaussian membership function. After the roads have been identified provisionally and their skeleton extracted, the skeleton can be vectorised and then used as direct input to a GIS for further analysis. The method was tested on an Ikonos “Geo” image covering Bilesavar in north-western Iran. For the suburban area of Bilesavar, the results showed that grey scale values ranged from 20 to 190 for non-roads and 226 to 228 for roads, the optimum width of the Gaussian kernel function was 3 and the SD was 0.4. It was also found that about 91% of main roads with a width of 6 to 12 pixels could be extracted from high resolution satellite imagery by the algorithm. The computer program for this study has been developed in visual C++ based on Windows 98

Notes: We have contacted the tip of a scanning tunneling microscope (STM) to a Co/Cu magnetic multilayer to locally measure the giant magnetoresistance (GMR) of the multilayer. Apart from a point-contact GMR, the measured MR also reflects a magnetostriction effect in the STM. The resulting GMR ratios are typically 10%, with occasional ratios up to 60%. We attribute spot-to-spot variations of the ratio to differences in the local structure of the magnetic multilayer. © 2000 American Institute of Physics.

Notes: Automatic surface reconstruction by means of digital image matching essentially involves computation in both image and object spaces. In image space, image matching is performed according to certain radiometric and geometric similarity criteria for conjugate point determination. The matching operations may therefore be regarded as decision–making processes. In practice, however, the similarity criteria for conjugate point determination demonstrate non–deterministic behaviour. Thus, the nature of these decision–making processes is more compatible with fuzzy reasoning concepts. In object space, on the other hand, surface reconstruction procedures, which operate on the basis of previously determined conjugate points, are essentially deterministic in nature and hence demand rigorous geometric modelling. In this paper, a new approach for automatic surface modelling is proposed, based on two different mathematical treatments: a fuzzy logic reasoning method for the conjugate point determination in image space; and a robust finite elements approach for the surface modelling in object space. Tests carried out on real data demonstrate the high potential of the strategy proposed.

Notes: Automatic surface reconstruction by means of digital image matching essentially involves computation in both image and object spaces. In image space, image matching is performed according to certain radiometric and geometric similarity criteria for conjugate point determination. The matching operations may therefore be regarded as decision-making processes. In practice, however, the similarity criteria for conjugate point determination demonstrate non-deterministic behaviour. Thus, the nature of these decision-making processes is more compatible with fuzzy reasoning concepts. In object space, on the other hand, surface reconstruction procedures, which operate on the basis of previously determined conjugate points, are essentially deterministic in nature and hence demand rigorous geometric modelling. In this paper, a new approach for automatic surface modelling is proposed, based on two different mathematical treatments: a fuzzy logic reasoning method for the conjugate point determination in image space; and a robust finite elements approach for the surface modelling in object space. Tests carried out on real data demonstrate the high potential of the strategy proposed.〈section xml:id="abs1-2"〉〈title type="main"〉RésuméLa reconstitution automatique d'une suface au moyen des techniques d'appariement d'images numériques passe par l'exécution de calculs dans les espaces object et image. Dans l'espace image l'appariement d'image qui permet de déterminer les points conjugués s'effectue selon certains critères de similitude géométrique et radiométrique. On peut donc considérer ces opérations d'appariement comme des démarches de prises de décisions. Toutefois il apparaî qu'en pratique les critères de similitude utilisés pour déterminer les points conjugués ne se comportent pas de manière très déterministe. Il s'ensuit que la nature de ces processus de prises de décisions s'apparente davantage à des concepts flous dans le raisonnement. En revancem. dans l'espace objet, les procédures de reconstitution des surfaces, qui s'appuient sur la base des points conjugués précé demment déterminés, sont essentiellement déterministes par nature et exigent par conséquent une modélisation géométrique rigoureuse. On propose dans cet article une nouvelle solution pour la modélisation automatique d'une surface, basée sur deux traitements mathématiques différents: une méthode de raisonnement à logique floue pour la détermination des points conjugués dans l'espace image, et un procédé robuste par éléments finis pour la modélisation de la surface dans l'espace object. Des essais effectués sur des données réelles ont montré que la stratégie proposée offrait de grandes possibilités.〈section xml:id="abs1-3"〉〈title type="main"〉ZusummenfussungBei einer automatischen Oberflächenrekonstruktion durch digitale Bildzuordnung werden üblicherweise Berechnungen sowohl im Bild- als auch im Objektraum durchgeführt. Im Bildraum basiert die Bildzuordnung auf bestimmte radiometrische und geometrische Ähnlichkeiten Für homologe Punkte jedoch ein nicht deterministisches Verhalten. Deshalb ist die Natur dieses Entscheidungsprozesses eher für Fuzzy-Logic Konzepte geeignet. Im Objektraum, sind die Verfahren zur Oberflächenrekonstruktion, die auf vorab bestimmte homologe Punkte basieren, von Natur aus deterministisch, und erfordern daher eine strenge geometrische Modellierung. In diesem Beitrag wird ein neuer Ansatz für die automatische oberflächenmodellierung vorgeschlagen, der auf zwei verschiedenen mathematischen Modellen beruht: eine Fuzzy Logic Methode für die Bestimmung von homologen Punkten im Bildraum, und einer robusten Finite Elemente Methode für die Oberflächenmodellierung im Objektraum. Experimente mit realen Daten zeigen das das große Potential der vorgeschlagenen Strategie.

Notes: This review describes some of the biochemical and toxicological properties of CYP2E1, especially as it relates to alcohol metabolism and toxicity and the establishment of human hepatoma HepG2 cell lines that overexpress human CYP2E1. Ethanol, polyunsaturated fatty acids, and iron were found to be cytotoxic in HepG2 cells that overexpress CYP2E1. GSH appears to be essential in protecting HepG2 cells against the CYP2E1-dependent cytotoxicity, and GSH levels were elevated owing to a twofold increase in activity and expression of glutamate cysteine ligase. We suggest that this up-regulation of GSH synthesis was an adaptive response to attenuate CYP2E1-dependent oxidative stress and toxicity. Induction of a state of oxidative stress appears to play a central role in the CYP2E1-dependent cytotoxicity. Mitochondrial membrane potential decreased in the CYP2E1-expressing HepG2 cells, and this decrease shared similar characteristics with the developing toxicity. Alcohol-dependent liver injury is likely to be a multifactorial process involving several mechanisms. We believe that the linkage between CYP2E1-dependent oxidative stress, mitochondrial injury, and GSH homeostasis contribute to the toxic actions of ethanol on the liver.

Notes: The yeast HAL1 gene facilitates K+/Na+ selectivity and salt tolerance of cells. Ectopic expression of HAL1 in transgenic tomato (Lycopersicon esculentum Mill.) plants minimized the reduction in fruit production caused by salt stress. Maintenance of fruit production by transgenic plants was correlated with enhanced growth under salt stress of calli derived from the plants. The HAL1 transgene enhanced water and K+ contents in both leaf calli and leaves in the presence of salt, which indicates that HAL1 functions in plants using a similar mechanism to that in yeast, namely by facilitating K+/Na+ selectivity under salt stress.

Notes: Critique originated by earlier theorization of environmental accounting, as a way of building environmentalist visibility of business, led Gray et al., to study environmental accounting in the dynamics of organizational change. They concluded that environmental accounting is being used to "negotiate the conception of the environment" by companies that have not significantly changed. In order to investigate whether Gray et al.'s model and conclusions apply to a different cultural context, we have conducted nine case studies in Spain. We found that Spanish organizations are not truly changing their conventional perception of the environment, even in those cases where generalized structural and organizational changes are taking place. Moreover, the use of environmental accounting is coupled with an attempt to negotiate and control the environmental agenda.

Notes: Workflow management includes concepts of special interest to the business organization field and for the automation of processes within a company. However, process modeling via workflow specifications and workflow management systems can be applied in any field where a workflow exists. The use of CASE tools provides a great increase in performance in information system development but, on the other hand, these tools do not support group work and make skipped steps possible in a methodology. Applying workflow management systems as a meta-CASE tool together with the use of cooperative methodologies - that aim to capture user requirements - can help us to solve problems related to shortcomings in monitoring, controls, and audit information system development.

Notes: A 75-year-old Caucasian male with papular elastolytic giant cell granuloma was treated successfully with hydroxychloroquine (200 mg p.o. bid for 4 months). Treatment had to be stopped because of early retinopathy. Treatment was started with quinacrine, which accomplished partial control.