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Showing papers by "Karlsruhe Institute of Technology published in 1999"


Journal ArticleDOI
TL;DR: In this article, two program packages for evaluating one-loop amplitudes are presented, which can work either in dimensional regularization or in constrained differential renormalization, and they are shown to be equivalent to regularization by dimensional reduction.

1,564 citations


Journal ArticleDOI
TL;DR: A classification scheme is provided, i.e. a description of the resource environment, the activity characteristics, and the objective function, respectively, which is compatible with machine scheduling and which allows to classify the most important models dealt with so far, and a unifying notation is proposed.

1,489 citations


Book
01 Oct 1999
TL;DR: The techniques treated in this text represent research as elucidated by the leaders in the field and are applied to real problems, such as hilllclimbing, simulated annealing, and tabu search.
Abstract: Optimization is a pivotal aspect of software design. The techniques treated in this text represent research as elucidated by the leaders in the field. The optimization methods are applied to real problems, such as hilllclimbing, simulated annealing, and tabu search.

1,461 citations


Journal ArticleDOI
01 Jun 1999
TL;DR: The DOXP pathway of IPP formation starts from D-glyceraldehyde-3-phosphate and pyruvate, with DOXP-synthase as the starting enzyme, and provides new insight into the regulation of chloroplast metabolism.
Abstract: In plants the biosynthesis of prenyllipids and isoprenoids proceeds via two independent pathways: (a) the cytosolic classical acetate/mevalonate pathway for the biosynthesis of sterols, sesquiterpenes, triterpenoids; and (b) the alternative, non-mevalonate 1-deoxy-d-xylulose-5-phosphate (DOXP) pathway for the biosynthesis of plastidic isoprenoids, such as carotenoids, phytol (a side-chain of chlorophylls), plastoquinone-9, isoprene, mono-, and diterpenes. Both pathways form the active C5-unit isopentenyl diphosphate (IPP) as the precursor from which all other isoprenoids are formed via head-to-tail addition. This review summarizes current knowledge of the novel 1-deoxy-d-xylulose-5-phosphate (DOXP) pathway for isopentenyl diphosphate biosynthesis, apparently located in plastids. The DOXP pathway of IPP formation starts from D-glyceraldehyde-3-phosphate (GA-3-P) and pyruvate, with DOXP-synthase as the starting enzyme. This pathway provides new insight into the regulation of chloroplast metabolism.

1,284 citations


Journal ArticleDOI
TL;DR: The history and trends of FT synthesis can be divided into several lines which are elaborated individually: • The changing environment of demand and supply of fossil energies and the more stringently upcoming aspects of pollution control, of cleanliness of the automotive fuels and of energy saving.
Abstract: Due to the large volume of existing literature on Fischer–Tropsch (FT) synthesis, the diversity of the subject and the actually reoriented interest, it seemed indicated to write a historical sketch about the process, putting also emphasis on present trends and future options. The matter is complicated and may be regarded from different positions. Thus history and trends have been divided into several lines which are elaborated individually: • The changing environment of demand and supply of fossil energies and the more stringently upcoming aspects of pollution control, of cleanliness of the automotive fuels and of energy saving. • The development of FT-reactors and processes, an area of highest present industrial activity and progress. • Preparation and performance of catalysts with particular concern about cobalt as the base metal. • FT intermediates and elemental reactions, difficult subjects as the FT multistep conversion features on the catalyst surface in the adsorbed state and kinetic principles as selective inhibition and spatial constraints seem to rule the regime. • Kinetic modelling of FT synthesis which has made great progress recently, particularly on the basis of newly provided detailed experimental data. Of course, presenting history and trends of FT synthesis on a few pages means generalising from many individual investigations and developments and also selection of only a few citations. So I want to apologise for all the contributions to science and technology around FT synthesis which I have missed to include into the article.

1,250 citations


Journal ArticleDOI
TL;DR: A working model for context is introduced, mechanisms to acquire context beyond location, and application of context-awareness in ultra-mobile computing are discussed and fusion of sensors for acquisition of information on more sophisticated contexts are explored.

1,222 citations


Journal ArticleDOI
03 Sep 1999-Science
TL;DR: A mevalonate-independent pathway of isoprenoid biosynthesis present in Plasmodium falciparum was shown to represent an effective target for chemotherapy of malaria and the presence of two genes encoding the enzymes DOXP synthase and DOXP reductoisomerase suggests that isoprene biosynthesis in P. falcIParum depends on the DOXP pathway.
Abstract: A mevalonate-independent pathway of isoprenoid biosynthesis present in Plasmodium falciparum was shown to represent an effective target for chemotherapy of malaria. This pathway includes 1-deoxy-D-xylulose 5-phosphate (DOXP) as a key metabolite. The presence of two genes encoding the enzymes DOXP synthase and DOXP reductoisomerase suggests that isoprenoid biosynthesis in P. falciparum depends on the DOXP pathway. This pathway is probably located in the apicoplast. The recombinant P. falciparum DOXP reductoisomerase was inhibited by fosmidomycin and its derivative, FR-900098. Both drugs suppressed the in vitro growth of multidrug-resistant P. falciparum strains. After therapy with these drugs, mice infected with the rodent malaria parasite P. vinckei were cured.

1,136 citations


Journal ArticleDOI
TL;DR: In this paper, a diagrammatic calculation of the leading two-loop QCD corrections to the masses of the neutral CP-even Higgs bosons in the Minimal Supersymmetric Standard Model is presented.
Abstract: We present detailed results of a diagrammatic calculation of the leading two-loop QCD corrections to the masses of the neutral CP-even Higgs bosons in the Minimal Supersymmetric Standard Model (MSSM). The two-loop corrections are incorporated into the full diagrammatic one-loop result and supplemented with refinement terms that take into account leading electroweak two-loop and higher-order QCD contributions. The dependence of the results for the Higgs-boson masses on the various MSSM parameters is analyzed in detail, with a particular focus on the part of the parameter space accessible at LEP2 and the upgraded Tevatron. For the mass of the lightest Higgs boson, mh, a parameter scan has been performed, yielding an upper limit on mh which depends only on tan�. The results for the Higgs-boson masses are compared with results obtained by renormalization group methods. Good agreement is found in the case of vanishing mixing in the scalar quark sector, while sizable deviations occur if squark mixing is taken into account.

936 citations


Proceedings ArticleDOI
06 Jul 1999
TL;DR: A new way to explore the benefits of a memory while minimizing its negative side effects is derived from a number of approaches that extend the evolutionary algorithm with implicit or explicit memory.
Abstract: Recently, there has been increased interest in evolutionary computation applied to changing optimization problems. The paper surveys a number of approaches that extend the evolutionary algorithm with implicit or explicit memory, suggests a new benchmark problem and examines under which circumstances a memory may be helpful. From these observations, we derive a new way to explore the benefits of a memory while minimizing its negative side effects.

750 citations


Proceedings ArticleDOI
27 Sep 1999
TL;DR: A layered real-time architecture for this kind of context-aware adaptation based on redundant collections of low-level sensors, which has shown that it is feasible to recognize contexts using sensors and that context information can be used to create new interaction metaphors.
Abstract: Mobile information appliances are increasingly used in numerous different situations and locations, setting new requirements to their interaction methods When the user's situation, place or activity changes, the functionality of the device should adapt to these changes In this work we propose a layered real-time architecture for this kind of context-aware adaptation based on redundant collections of low-level sensors Two kinds of sensors are distinguished: physical and logical sensors, which give cues from environment parameters and host information A prototype board that consists of eight sensors was built for experimentation The contexts are derived from cues using real-time recognition software, which was constructed after experiments with Kohonen's Self-Organizing Maps and its variants A personal digital assistant (PDA) and a mobile phone were used with the prototype to demonstrate situational awareness On the PDA font size and backlight were changed depending on the demonstrated contexts while in mobile phone the active user profile was changed The experiments have shown that it is feasible to recognize contexts using sensors and that context information can be used to create new interaction metaphors

634 citations


Journal ArticleDOI
25 Mar 1999-Nature
TL;DR: In this paper, a tunable Josephson couplings were proposed for solid-state qubits that utilizes controllable, low-capacitance Josephson junctions, and the design exploits coherent tunnelling of Cooper pairs in the superconducting state.
Abstract: Quantum computers, if available, could perform certain tasks much more efficiently than classical computers by exploiting different physical principles1,2,3. A quantum computer would be comprised of coupled, two-state quantum systems or qubits, whose coherent time evolution must be controlled in a computation. Experimentally, trapped ions4,5, nuclear magnetic resonance6,7,8 in molecules, and quantum optical systems9 have been investigated for embodying quantum computation. But solid-state implementations10,11,12,13,14 would be more practical, particularly nanometre-scale electronic devices: these could be easily embedded in electronic circuitry and scaled up to provide the large numbers of qubits required for useful computations. Here we present a proposal for solid-state qubits that utilizes controllable, low-capacitance Josephson junctions. The design exploits coherent tunnelling of Cooper pairs in the superconducting state, while employing the control mechanisms of single-charge devices: single- and two-bit operations can be controlled by gate voltages. The advantages of using tunable Josephson couplings include the simplification of the operation and the reduction of errors associated with permanent couplings.

Book ChapterDOI
04 Jan 1999
TL;DR: Ontobroker is developed which uses formal ontologies to extract, reason, and generate metadata in the WWW, and the generation of RDF descriptions enables the exploitation of the ontological information in RDF-based applications.
Abstract: The World Wide Web (WWW) can be viewed as the largest multimedia database that has ever existed. However, its support for query answering and automated inference is very limited. Metadata and domain specific ontologies were proposed by several authors to solve this problem. We developed Ontobroker which uses formal ontologies to extract, reason, and generate metadata in the WWW. The paper describes the formalisms and tools for formulating queries, defining ontologies, extracting metadata, and generating metadata in the format of the Resource Description Framework (RDF), as recently proposed by the World Wide Web Consortium (W3C). These methods provide a means for semantic based query handling even if the information is spread over several sources. Furthermore, the generation of RDF descriptions enables the exploitation of the ontological information in RDF-based applications.

Journal ArticleDOI
TL;DR: In this article, the effects of publicly funded research at universities, polytechnics and federal research labs on industrial innovations in Germany were examined and the characteristics of companies that benefit from the findings of public research institutions were discussed.

Journal ArticleDOI
TL;DR: In this paper, the properties of mesoscopic normal metal/superconductor heterostructures are described in the framework of quasiclassical many-body techniques, both in equilibrium and nonequilibrium situations.

Journal ArticleDOI
TL;DR: In this article, the stress-strain behavior of granular materials can be modelled with hypoplastic constitutive relations, and a procedure for the determination of its parameters is described in detail.
Abstract: The stress–strain behaviour of granular materials can be modelled with hypoplastic constitutive relations. A hypoplastic model is briefly introduced for the axially symmetric case, and a procedure for the determination of its parameters is described in detail. It is shown, for several sands and one gravel, that all parameters of the hypoplastic model are closely related to the granulometric properties of grain assemblies. Recalculations of some element tests are presented in order to verify the proposed procedure. Copyright © 1999 John Wiley & Sons, Ltd.

Journal ArticleDOI
TL;DR: In this paper, the performance of various modified iron and cobalt catalysts was investigated for CO2 hydrogenation and it was shown that alumina was the best catalyst for CO 2 hydrogenation.
Abstract: Hydrogenation of CO, CO2 and their mixtures has been comparatively studied with a Co–MnO–Aerosil–Pt and a Fe–Al2O3–Cu–K catalyst at the University of Karlsruhe. With iron catalysts as promising for CO2 hydrogenation, their composition was varied: (1) several supports (SiO2, TiO2, Al2O3), (2) alkali promotion (Li, Na, K, Rb), (3) usage of Zeolite Y as catalyst component. The catalysts were characterised by adsorption methods, XRD, TPR and temperature programmed decarburisation after a H2/CO2 treatment (Korea Research Institute of Chemical Technology). Iron and cobalt catalysts behaved differently in CO2 hydrogenation. With the alkalised iron catalyst the same hydrocarbon product composition was obtained from a H2/CO2 and from a H2/CO synthesis gas in spite of the CO partial pressure remaining low, specifically due to water gas shift equilibrium constraints. With the cobalt catalyst at increasing CO2 and respectively decreasing CO content of the syngas, the product composition shifted from a Fischer–Tropsch type (mainly higher hydrocarbons) to almost exclusively methane. These basically different catalyst behaviours are explained by different modes of formation of the kinetic regime of FT synthesis—selective inhibition of methane formation and the selective inhibition of product desorption as a prerequisite for chain growth—in the case of iron through irreversible carbiding and alkali surface coverage and in case of cobalt through strong reversible CO adsorption. Investigation of the various modified iron catalysts showed alumina to be the best support for CO2 hydrogenation and potassium to act as a powerful promotor. With the Fe–Y–zeolite–alkali catalysts, a decrease of methane selectivity was observed in the order Li < Na < K < Rb being applied as promotors.

Journal ArticleDOI
TL;DR: In this paper, a kinetic study on the thermal degradation of polyethylene and polypropylene is presented, where the degradation of these polymers is investigated under isothermal conditions using a gradient free reactor with on-line mass spectrometry.

Journal ArticleDOI
TL;DR: The Andean foreland deformation comprises three basically different structural styles: (1) thin-skinned thrust belts detached within the sedimentary cover, (2) thick-skin thrust belts with an inferred basal detachment in the basement, at 10-20 km depth, and (3) foreland basement thrusts which possibly affect the entire crust as mentioned in this paper.

Journal ArticleDOI
TL;DR: In vitro results demonstrate for the first time the use of a semiquantitative RT-PCR technique for screening estrogenicity by assaying mRNA induction of the estrogenic biomarker vitellogenin in vitro and in vivo.

Journal Article
TL;DR: The expression of osteopontin, CD44 variants, and integrins has been correlated with tumorigenesis and metastasis and it is shown that these proteins cooperate to enhance cell motility.
Abstract: The expression of osteopontin (OPN), CD44 variants, and integrins has been correlated with tumorigenesis and metastasis. Here we show that these proteins cooperate to enhance cell motility. First, we demonstrate that several different CD44 variants bind to OPN in an arginine-glycineaspartic acid-independent manner, but that the standard form of CD44 does not. These CD44 variants bind to both the amino- and COOH-terminal portions of OPN independently of the arginine-glycine-aspartic acid sequence, suggesting that multiple domains on OPN can be bound by the CD44 variants. Antibodies directed against the integrin beta1 subunit are able to inhibit this binding. The binding of CD44 variants to OPN is significantly augmented by both anti-CD44s and anti-CD44v antibodies. This augmentation by anti-CD44 antibodies is OPN specific and, again, can be blocked by anti-beta1 antibodies. Finally, we show that OPN binding by CD44 variants/beta1-containing integrins promotes cell spreading, motility, and chemotactic behavior.

Journal ArticleDOI
TL;DR: In this paper, a remote sensing technique is presented to estimate the chlorophyll content in higher plants, where the ratio between chlorophyl fluorescence at 735 nm and in the range 700-710 nm, F735/F700 was found to be linearly proportional to the chlorophll content (with determination coefficient, r2, more than 0.95).

Journal ArticleDOI
04 Nov 1999-Oncogene
TL;DR: A novel regulatory action of the androgen receptor is demonstrated and it is proved that in addition to its known transcriptional effects, it also uses non-conventional means to modulate several cellular signalling processes.
Abstract: Androgens are important growth regulators in prostate cancer. Their known mode of action in target cells requires binding to a cytoplasmic androgen receptor followed by a nuclear translocation event and modulation of the expression of specific genes. Here, we report another mode of action of this receptor. Treatment of androgen responsive prostate cancer cells with dihydrotestosterone leads to a rapid and reversible activation of mitogen-activated protein kinases MAPKs (also called extracellular signal-regulated kinases or Erks). Transient transfection assays demonstrated that the androgen receptor-mediated activation of MAP kinase results in enhanced activity of the transcription factor Elk-1. This action of the androgen receptor differs from its known transcriptional activity since it is rapid and insensitive to androgen antagonists such as hydroxyflutamide or casodex. Biochemical studies as well as analyses with dominant negative mutants showed the involvement of kinases such as MAPK/Erk kinase, phosphatidyl-inositol 3-kinase and protein kinase C in the androgen receptor-mediated activation of MAP kinase. These results demonstrate a novel regulatory action of the androgen receptor and prove that in addition to its known transcriptional effects, it also uses non-conventional means to modulate several cellular signalling processes.

Journal ArticleDOI
TL;DR: The person model is augmented by a simple motion model of constant velocity for all DOFs which is used in the prediction step of the IEKF and in the update step, both region and edge information are used.

Journal ArticleDOI
TL;DR: E ectopically expressed Rh5 and Rh6 in the major class of photoreceptor cells (R1–R6) and show them to be biologically active in their new environment and to be the first member of this class to be functionally characterized.
Abstract: Color discrimination requires the input of different photoreceptor cells that are sensitive to different wavelengths of light. The Drosophila visual system contains multiple classes of photoreceptor cells that differ in anatomical location, synaptic connections, and spectral sensitivity. The Rh5 and Rh6 opsins are expressed in nonoverlapping sets of R8 cells and are the only Drosophila visual pigments that remain uncharacterized. In this study, we ectopically expressed Rh5 and Rh6 in the major class of photoreceptor cells (R1-R6) and show them to be biologically active in their new environment. The expression of either Rh5 or Rh6 in "blind" ninaE(17) mutant flies, which lack the gene encoding the visual pigment of the R1-R6 cells, fully rescues the light response. Electrophysiological analysis showed that the maximal spectral sensitivity of the R1-R6 cells is shifted to 437 or 508 nm when Rh5 or Rh6, respectively, is expressed in these cells. These spectral sensitivities are in excellent agreement with intracellular recordings of the R8p and R8y cells measured in Calliphora and Musca. Spectrophotometric analyses of Rh5 and Rh6 in vivo by microspectrophotometry, and of detergent-extracted pigments in vitro, showed that Rh5 is reversibly photoconverted to a stable metarhodopsin (lambda(max) = 494 nm), whereas Rh6 appears to be photoconverted to a metarhodopsin (lambda(max) = 468 nm) that is less thermally stable. Phylogenetically, Rh5 belongs to a group of short-wavelength-absorbing invertebrate visual pigments, whereas Rh6 is related to a group of long-wavelength-absorbing pigments and is the first member of this class to be functionally characterized.

Journal ArticleDOI
TL;DR: In this paper, a case study of gaseous pollutant dispersion in street canyons is presented, where tracer gas experiments are performed in a neutrally stratified wind tunnel.

Journal ArticleDOI
TL;DR: In this paper, the synthesis and characterization of latex particles consisting of a poly(styrene) core and a shell of linear poly(acrylic acid) (PAA) chains are described.
Abstract: The synthesis and characterization of latex particles consisting of a poly(styrene) (PS) core and a shell of linear poly(acrylic acid) (PAA) chains are described. The particles have been synthesize...

Journal ArticleDOI
13 May 1999-Langmuir
TL;DR: Amino-terminated self-assembled monolayers on SiO2 surfaces were obtained by means of a simple silylation method as mentioned in this paper, which showed that the amino-silane is covalently bonded to the silica surface.
Abstract: Amino-terminated self-assembled monolayers on SiO2 surfaces were obtained by means of a simple silylation method. The thickness of the monolayers was measured with ellipsometry. Washing tests with strong solvents indicated that the amino-silane is covalently bonded to the silica surface. Amino-terminated monolayers on SiO2 surfaces are very flat and homogeneous, as shown by atomic force microscopy. Contact angle measurements showed that such monolayers interact very quickly with air impurities and should be used just after the silylation. The adhesion between the amino-terminated surface and gold was evidenced by ultrasonic and tape tests.

Journal ArticleDOI
TL;DR: In this paper, the authors present a systematic overview of the cross sections for the production of pairs of (light) neutral Higgs bosons at the LHC for the Standard Model and its minimal supersymmetric extension.
Abstract: The reconstruction of the Higgs potential in the Standard Model or supersymmetric theories demands the measurement of the trilinear Higgs couplings. These couplings affect the multiple production of Higgs bosons at high energy colliders. We present a systematic overview of the cross sections for the production of pairs of (light) neutral Higgs bosons at the LHC. The analysis is carried out for the Standard Model and its minimal supersymmetric extension.

Journal ArticleDOI
TL;DR: Sures et al. as mentioned in this paper discuss the phenomenon of conspicuous metal accumulation by parasites and how this might be applied to environmental monitoring, and suggest how environmental science and parasitology might profit from each other in the near future.

Journal ArticleDOI
TL;DR: In this paper, the role of secondary olefinear reactions during Fischer-Tropsch synthesis and the reason for their chain length dependence were investigated and extensive studies on their extent and selectivity were performed by co-feeding α-olefins during FT synthesis with cobalt catalysts in a gradientless slurry reactor.
Abstract: Based on the picture of Fischer–Tropsch synthesis as an ideal polymerization reaction it is easily noticeable that primarily formed product olefins can undergo secondary reactions, which generally lead to carbon number dependencies of certain olefin reaction pathways and thereby to modifications of product distributions. To obtain more insight into the role of secondary olefin reactions during Fischer–Tropsch synthesis and the reason for their chain length dependence, extensive studies on their extent and selectivity and particularly their chain length dependence at different reaction conditions (variation of CO partial pressure and reaction temperature) were performed by co-feeding α-olefins (C2–C11) during FT synthesis with cobalt catalysts in a gradientless slurry reactor. Conversion of the added olefins revealed a strong carbon number dependence exhibiting a sharp minimum at C3. The observed chain length dependencies of individual reaction pathways (hydrogenation and incorporation) are in agreement with the selectivities observed in the base case experiments without olefin addition and mainly due to carbon number dependent solubility of the olefins in the liquid reaction product.