Showing papers by "Bielefeld University published in 2008"

Relativistic viscous hydrodynamics, conformal invariance, and holography

Abstract: We consider second-order viscous hydrodynamics in conformal field theories at finite temperature. We show that conformal invariance imposes powerful constraints on the form of the second-order corrections. By matching to the AdS/CFT calculations of correlators, and to recent results for Bjorken flow obtained by Heller and Janik, we find three (out of five) second-order transport coefficients in the strongly coupled = 4 supersymmetric Yang-Mills theory. We also discuss how these new coefficents can arise within the kinetic theory of weakly coupled conformal plasmas. We point out that the Muller-Israel-Stewart theory, often used in numerical simulations, does not contain all allowed second-order terms and, frequently, terms required by conformal invariance.

Dissociation of Cognitive and Emotional Empathy in Adults with Asperger Syndrome Using the Multifaceted Empathy Test (MET)

Abstract: Empathy is a multidimensional construct consisting of cognitive (inferring mental states) and emotional (empathic concern) components. Despite a paucity of research, individuals on the autism spectrum are generally believed to lack empathy. In the current study we used a new, photo-based measure, the Multifaceted Empathy Test (MET), to assess empathy multidimensionally in a group of 17 individuals with Asperger syndrome (AS) and 18 well-matched controls. Results suggested that while individuals with AS are impaired in cognitive empathy, they do not differ from controls in emotional empathy. Level of general emotional arousability and socially desirable answer tendencies did not differ between groups. Internal consistency of the MET's scales ranged from .71 to .92, and convergent and divergent validity were highly satisfactory.

Migrants as transnational development agents: An inquiry into the newest round of the migration - development nexus.

Abstract: Migrant networks and organisations have emerged as development agents. They interact with state institutions in flows of financial remittances, knowledge, and political ideas. In the discursive dimension, the new enthusiasm on the part of OECD states and international organisations, such as the World Bank, for migrant remittances, migrant associations and their role in development, is a sign of two trends which have coincided. Firstly, community as a principle of development has come to supplement principles of social order such as the market and the state. Secondly, in the current round of the migration–development nexus, migrants in general and transnational collective actors in particular have been constituted by states and international organisations as a significant agent. In the institutional dimension, agents such as hometown associations, networks of businesspersons, epistemic networks and political diasporas have emerged as collective actors. These formations are not unitary actors, and they are frequently in conflict with states and communities of origin. The analysis concludes with reflections of how national states structure the transnational spaces in which non-state actors are engaged in cross-border flows, leading towards a tight linkage between migration control, immigrant incorporation and development cooperation. Copyright © 2007 John Wiley & Sons, Ltd.

QCD equation of state with almost physical quark masses

Abstract: We present results on the equation of state in QCD with two light quark flavors and a heavier strange quark. Calculations with improved staggered fermions have been performed on lattices with temporal extent ${N}_{\ensuremath{\tau}}=4$ and 6 on a line of constant physics with almost physical quark mass values; the pion mass is about 220 MeV, and the strange quark mass is adjusted to its physical value. High statistics results on large lattices are obtained for bulk thermodynamic observables, i.e. pressure, energy and entropy density, at vanishing quark chemical potential for a wide range of temperatures, $140\text{ }\text{ }\mathrm{MeV}\ensuremath{\le}T\ensuremath{\le}800\text{ }\text{ }\mathrm{MeV}$. We present a detailed discussion of finite cutoff effects which become particularly significant for temperatures larger than about twice the transition temperature. At these high temperatures we also performed calculations of the trace anomaly on lattices with temporal extent ${N}_{\ensuremath{\tau}}=8$. Furthermore, we have performed an extensive analysis of zero temperature observables including the light and strange quark condensates and the static quark potential at zero temperature. These are used to set the temperature scale for thermodynamic observables and to calculate renormalized observables that are sensitive to deconfinement and chiral symmetry restoration and become order parameters in the infinite and zero quark mass limits, respectively.

Health Technology Assessment (HTA)

Abstract: Da im Gesundheitswesen die Ressourcen begrenzt sind, mussen auf verschiedenen Ebenen Entscheidungen daruber getroffen werden, welche Guter und Dienstleistungen in welcher Qualitat und Beschaffenheit zu welchem Zeitpunkt fur welche Patienten und andere Konsumenten bereitgestellt werden sollen. Je nach Organisationstyp des jeweiligen Gesundheitssystems erfolgt die Entscheidungsfindung auf dezentraler Ebene (z. B. die Medikamentenlistung eines Krankenhauses), regionaler Ebene (z. B. der Abschluss regionaler Versorgungsvertrage) oder nationaler Ebene. In Deutschland fallen beispielsweise die Entscheidungen des Gemeinsamen Bundesausschusses (G-BA) uber die Erstattungsfahigkeit und den maximal erstatteten Preis von Arzneimitteln sowie die Zulassung ambulanter Verfahren fur die Regelversorgung in die letztgenannte Kategorie. Anders als in anderen Bereichen des Wirtschaftssystems werden damit wichtige Entscheidungen uber die Inanspruchnahme von Gutern und Dienstleistungen nicht vom Konsumenten direkt, sondern von teilweise hoch zentralisierten Gremien gefallt, die fur diese Aufgabe bei rationaler Erfullung ein hohes Mas an Informationstransparenz benotigen.

Foundation of statistical mechanics under experimentally realistic conditions.

Abstract: We demonstrate the equilibration of isolated macroscopic quantum systems, prepared in nonequilibrium mixed states with a significant population of many energy levels, and observed by instruments with a reasonably bound working range compared to the resolution limit. Both properties are satisfied under many, if not all, experimentally realistic conditions. At equilibrium, the predictions and limitations of statistical mechanics are recovered.

Microbial Ecology of Four Coral Atolls in the Northern Line Islands

Abstract: Microbes are key players in both healthy and degraded coral reefs. A combination of metagenomics, microscopy, culturing, and water chemistry were used to characterize microbial communities on four coral atolls in the Northern Line Islands, central Pacific. Kingman, a small uninhabited atoll which lies most northerly in the chain, had microbial and water chemistry characteristic of an open ocean ecosystem. On this atoll the microbial community was equally divided between autotrophs (mostly Prochlorococcus spp.) and heterotrophs. In contrast, Kiritimati, a large and populated (~5500 people) atoll, which is most southerly in the chain, had microbial and water chemistry characteristic of a near-shore environment. On Kiritimati, there were 10 times more microbial cells and virus-like particles in the water column and these microbes were dominated by heterotrophs, including a large percentage of potential pathogens. Culturable Vibrios were common only on Kiritimati. The benthic community on Kiritimati had the highest prevalence of coral disease and lowest coral cover. The middle atolls, Palmyra and Tabuaeran, had intermediate densities of microbes and viruses and higher percentages of autotrophic microbes than either Kingman or Kiritimati. The differences in microbial communities across atolls could reflect variation in 1) oceaonographic and/or hydrographic conditions or 2) human impacts associated with land-use and fishing. The fact that historically Kingman and Kiritimati did not differ strongly in their fish or benthic communities (both had large numbers of sharks and high coral cover) suggest an anthropogenic component in the differences in the microbial communities. Kingman is one of the world's most pristine coral reefs, and this dataset should serve as a baseline for future studies of coral reef microbes. Obtaining the microbial data set, from atolls is particularly important given the association of microbes in the ongoing degradation of coral reef ecosystems worldwide.

Do atmospheric aerosols form glasses

Abstract: . A new process is presented by which water soluble organics might influence ice nucleation, ice growth, chemical reactions and water uptake of aerosols in the upper troposphere: the formation of glassy aerosol particles. Glasses are disordered amorphous (non-crystalline) solids that form when a liquid is cooled without crystallization until the viscosity increases exponentially and molecular diffusion practically ceases. The glass transition temperatures, Tg, homogeneous ice nucleation temperatures, Thom, and ice melting temperatures, Tm, of various aqueous inorganic, organic and multi-component solutions are investigated with a differential scanning calorimeter. The investigated solutes are: various polyols, glucose, raffinose, levoglucosan, an aromatic compound, sulfuric acid, ammonium bisulfate and mixtures of dicarboxylic acids (M5), of dicarboxylic acids and ammonium sulfate (M5AS), of two polyols, of glucose and ammonium nitrate, and of raffinose and M5AS. The results indicate that aqueous solutions of the investigated inorganic solutes show Tg values that are too low to be of atmospheric importance. In contrast, aqueous organic and multi-component solutions readily form glasses at low but atmospherically relevant temperatures (≤230 K). To apply the laboratory data to the atmospheric situation, the measured phase transition temperatures were transformed from a concentration to a water activity scale by extrapolating water activities determined between 252 K and 313 K to lower temperatures. The obtained state diagrams reveal that the higher the molar mass of the aqueous organic or multi-component solutes, the higher Tg of their respective solutions at a given water activity. To a lesser extent, Tg also depends on the hydrophilicity of the organic solutes. Therefore, aerosol particles containing larger (≳150 g mol−1) and more hydrophobic organic molecules are more likely to form glasses at intermediate to high relative humidities in the upper troposphere. Our results suggest that the water uptake of aerosols, heterogeneous chemical reactions in aerosol particles, as well as ice nucleation and ice crystal growth can be significantly impeded or even completely inhibited in organic-enriched aerosols at upper tropospheric temperatures with implications for cirrus cloud formation and upper tropospheric relative humidity.

Can machines think? Interaction and perspective taking with robots investigated via fMRI.

Abstract: Background When our PC goes on strike again we tend to curse it as if it were a human being. Why and under which circumstances do we attribute human-like properties to machines? Although humans increasingly interact directly with machines it remains unclear whether humans implicitly attribute intentions to them and, if so, whether such interactions resemble human-human interactions on a neural level. In social cognitive neuroscience the ability to attribute intentions and desires to others is being referred to as having a Theory of Mind (ToM). With the present study we investigated whether an increase of human-likeness of interaction partners modulates the participants' ToM associated cortical activity. Methodology/Principal Findings By means of functional magnetic resonance imaging (subjects n = 20) we investigated cortical activity modulation during highly interactive human-robot game. Increasing degrees of human-likeness for the game partner were introduced by means of a computer partner, a functional robot, an anthropomorphic robot and a human partner. The classical iterated prisoner's dilemma game was applied as experimental task which allowed for an implicit detection of ToM associated cortical activity. During the experiment participants always played against a random sequence unknowingly to them. Irrespective of the surmised interaction partners' responses participants indicated having experienced more fun and competition in the interaction with increasing human-like features of their partners. Parametric modulation of the functional imaging data revealed a highly significant linear increase of cortical activity in the medial frontal cortex as well as in the right temporo-parietal junction in correspondence with the increase of human-likeness of the interaction partner (computer

A multilayer multiconfigurational time-dependent Hartree approach for quantum dynamics on general potential energy surfaces.

Abstract: The multiconfigurational time-dependent Hartree (MCTDH) approach facilitates multidimensional quantum dynamics calculations by representing the wavepacket in an optimal set of time-dependent basis functions, called single-particle functions Choosing these single-particle functions to be themselves multidimensional wavefunctions which are represented using a MCTDH representation, a multilayer MCTDH scheme has been constructed and used for quantum dynamics calculations treating up to 1000 degrees of freedom rigorously [Wang and Thoss, J Chem Phys 199, 1289 (2003)] The present work gives a practical scheme which facilitates the application of the multilayer MCTDH approach, which previously has only been employed to study systems described by model-type Hamiltonians, to molecular systems described by more complicated Hamiltonians and general potential energy surfaces A multilayer extension of the correlation discrete variable representation (CDVR) scheme employed in MCTDH calculations studying quantum dynamics on general potential energy surfaces is developed and tested in a simple numerical application The resulting multilayer MCTDH/CDVR approach might offer a perspective to rigorously describe the quantum dynamics of larger polyatomic systems

Quantum oscillations in a molecular magnet

Abstract: Molecular magnets are a type of molecule containing multiple magnetic ions whose spins are tightly coupled to give a single 'collective' spin. The quantum mechanical properties of this collective spin are attracting attention as a possible basis for the functional unit of a quantum computer. Until now it has not been clear whether the quantum spin states of these molecular entities are sufficiently long-lived to permit useful computation, but new work suggests that they are. Bertaina et al. observed pronounced quantum oscillations between the spin states of one such molecular magnet, consistent with long-lived quantum coherence, in this system at least. They also outline a scheme by which, through careful material design, these properties could be harnessed in a practical context. Molecular magnets are a class of molecule containing multiple magnetic ions whose spins are tightly coupled to give a single 'collective' spin. But it has remained an open question whether the quantum spin states of these molecular entities are sufficiently long-lived to permit useful computation. Pronounced quantum oscillations between the spin states of one such molecular magnet have been observed, indicating that quantum coherence is long-lived. The term ‘molecular magnet’ generally refers to a molecular entity containing several magnetic ions whose coupled spins generate a collective spin, S (ref. 1). Such complex multi-spin systems provide attractive targets for the study of quantum effects at the mesoscopic scale. In these molecules, the large energy barriers between collective spin states can be crossed by thermal activation or quantum tunnelling, depending on the temperature or an applied magnetic field2,3,4. There is the hope that these mesoscopic spin states can be harnessed for the realization of quantum bits—‘qubits’, the basic building blocks of a quantum computer—based on molecular magnets5,6,7,8. But strong decoherence9 must be overcome if the envisaged applications are to become practical. Here we report the observation and analysis of Rabi oscillations (quantum oscillations resulting from the coherent absorption and emission of photons driven by an electromagnetic wave10) of a molecular magnet in a hybrid system, in which discrete and well-separated magnetic clusters are embedded in a self-organized non-magnetic environment. Each cluster contains 15 antiferromagnetically coupled S = 1/2 spins, leading to an S = 1/2 collective ground state11,12,13. When this system is placed into a resonant cavity, the microwave field induces oscillatory transitions between the ground and excited collective spin states, indicative of long-lived quantum coherence. The present observation of quantum oscillations suggests that low-dimension self-organized qubit networks having coherence times of the order of 100 μs (at liquid helium temperatures) are a realistic prospect.

Phylogenetic classification of short environmental DNA fragments

Abstract: Metagenomics is providing striking insights into the ecology of microbial communities. The recently developed massively parallel 454 pyrosequencing technique gives the opportunity to rapidly obtain metagenomic sequences at a low cost and without cloning bias. However, the phylogenetic analysis of the short reads produced represents a significant computational challenge. The phylogenetic algorithm CARMA for predicting the source organisms of environmental 454 reads is described. The algorithm searches for conserved Pfam domain and protein families in the unassembled reads of a sample. These gene fragments (environmental gene tags, EGTs), are classified into a higher-order taxonomy based on the reconstruction of a phylogenetic tree of each matching Pfam family. The method exhibits high accuracy for a wide range of taxonomic groups, and EGTs as short as 27 amino acids can be phylogenetically classified up to the rank of genus. The algorithm was applied in a comparative study of three aquatic microbial samples obtained by 454 pyrosequencing. Profound differences in the taxonomic composition of these samples could be clearly revealed.

Taxonomy and definitions for sonification and auditory display

Abstract: Sonification is still a relatively young research field and many terms such as sonification, auditory display, auralization, audification have been used without a precise definition. Recent developments such as the introduction of Model-Based Sonification, the establishment of interactive sonification and the increased interest in sonification from arts have raised the need to revisit the definitions in order to move towards a clearer terminology. This paper introduces a new definition for sonification and auditory display that emphasizes the necessary and sufficient conditions for organized sound to be called sonification. It furthermore suggests a taxonomy, and discusses the relation between visualization and sonification. A hierarchy of closed-loop interactions is furthermore introduced. This paper aims to initiate vivid discussion towards the establishment of a deeper theory of sonification and auditory display.

HAG2/MYB76 and HAG3/MYB29 exert a specific and coordinated control on the regulation of aliphatic glucosinolate biosynthesis in Arabidopsis thaliana

Abstract: In a previous transactivation screen, two Arabidopsis thaliana R2R3-MYB transcription factors, HAG2/MYB76 and HAG3/MYB29, along with the already characterized HAG1/MYB28, were identified as putative regulators of aliphatic glucosinolate biosynthesis. • Molecular and biochemical characterization of HAG2/MYB76 and HAG3/MYB29 functions was performed using transformants with increased or repressed transcript levels. Real-time PCR assays, cotransformation assays and measurements of glucosinolate contents were used to assess the impact of both MYB factors on the steady-state level of glucosinolate biosynthetic genes and accumulation of aliphatic glucosinolates. • Both HAG2/MYB76 and HAG3/MYB29 were shown to be positive regulators of aliphatic glucosinolate biosynthesis. Expression of promoter-β- glucuronidase (GUS) fusions indicated GUS activities in both vegetative and generative organs, with distinct characteristics for each MYB factor. HAG1/MYB28, HAG2/MYB76 and HAG3/MYB29 reciprocally transactivated each other in the control of aliphatic glucosinolate biosynthesis and downregulated the expression of genes involved in the control of indolic glucosinolate biosynthesis, pointing to a reciprocal negative regulation of these two pathways. • All three HAG transcription factors exert a coordinated control on aliphatic glucosinolate biosynthesis.

Heavy-ion collisions at the LHC-Last call for predictions

Abstract: This writeup is a compilation of the predictions for the forthcoming Heavy Ion Program at the Large Hadron Collider, as presented at the CERN Theory Institute 'Heavy Ion Collisions at the LHC - Last Call for Predictions', held from 14th May to 10th June 2007.

Interspecies signalling via the Stenotrophomonas maltophilia diffusible signal factor influences biofilm formation and polymyxin tolerance in Pseudomonas aeruginosa

Abstract: Interspecies signalling through the action of diffusible signal molecules can influence the behaviour of organisms growing in polymicrobial communities. Stenotrophomonas maltophilia and Pseudomonas aeruginosa occur ubiquitously in the environment and can be found together in diverse niches including the rhizosphere of plants and the cystic fibrosis lung. In mixed species biofilms, S. maltophilia substantially influenced the architecture of P. aeruginosa structures, which developed as extended filaments. This effect depended upon the synthesis of the diffusible signal factor (DSF) by S. maltophilia and could be mimicked by the addition of synthetic DSF. This response of P. aeruginosa to DSF required PA1396, a sensor kinase with an input domain of related amino acid sequence to the sensory input domain of RpfC, which is responsible for DSF perception in xanthomonads. Mutation of PA1396 or addition of DSF to P. aeruginosa led to increased levels of a number of proteins with roles in bacterial stress tolerance, including those implicated in resistance to cationic antimicrobial peptides. This effect was associated with increased tolerance to polymyxins. Homologues of PA1396 occur in a number of phytopathogenic and plant-associated pseudomonads, suggesting that modulation of bacterial behaviour through DSF-mediated interspecies signalling with xanthomonads is a phenomenon that occurs widely.

Trend of hip fracture incidence in Germany 1995-2004: a population-based study.

Abstract: We analyzed hip fracture incidence trends in Germany 1995-2004, using national hospital discharge register. Crude incidences per 100,000 increased from 121.2 (95% CI 120.5-121.9) in 1995 to 140.9 (140.2-141.7) in 2004. Age-sex-adjusted annual incidence ratios showed a statistically significant, but only slight increase (1.01, p < 0.01), compared to higher rises in the past. Trends differed markedly with sex, age, and regions. Data concerning actual trends of the hip fracture incidence and differences for sex, age, and region are limited. We analyzed hip fracture incidence trends in Germany 1995-2004, using the national hospital discharge register. Crude incidences per 100,000 increased from 121.2 (95% CI 120.5-121.9) in 1995 to 140.9 (140.2-141.7) in 2004. Age-sex-adjusted annual incidence ratios showed a statistically significant, but only slight increase (1.01, p < 0.01), compared to higher rises in the past. Trends differed markedly with sex, age, and regions. Analysis of annual hip fracture incidences using the national hospital discharge register. Estimate of age-sex-adjusted changes was found by using Poisson regression (incidence rate ratios, IRR). The number of patients with at least one hospital admission for hip fracture increased (1995: n = 99,141; 2004: n = 116,281). Crude incidences per 100,000 were 121.2 (95% confidence interval 120.5-121,9) and 140.9 (140.2-141.7), respectively. The age-sex-adjusted hip fracture incidence increased statistically significantly, but only slightly (IRR per year: 1.01; 1.00-1.01; IRR 1995-2004: 1.05, p < 0.01). In men aged 40 years or older, incidences increased. In women, there was a tendency of a decrease up to 74 years of age, but also a significant increase in higher age groups. In people 0-39 years, the incidence declined markedly (IRR 1995-2004, men 0.74; 0.69-0.79, women 0.62; 0.55-0.69, both p < 0.01). The increase was significantly higher in Eastern compared to Western Germany (interaction: p = 0.002), and differences between East and West decreased. In contrast to earlier years, the hip fracture incidence in Germany 1995-2004 increased only slightly, with a decline in younger people, but increases in older ages, particularly in men. Regional differences decreased.

“Imaging” combustion chemistry via multiplexed synchrotron-photoionization mass spectrometry

Abstract: The combination of multiplexed mass spectrometry with photoionization by tunable-synchrotron radiation has proved to be a powerful tool to investigate elementary reaction kinetics and the chemistry of low-pressure flames. In both of these applications, multiple-mass detection and the ease of tunability of synchrotron radiation make it possible to acquire full sets of data as a function of mass, photon energy, and of the physical dimension of the system, e.g. distance from the burner or time after reaction initiation. The data are in essence an indirect image of the chemistry. The data can be quantitatively correlated and integrated along any of several dimensions to compare to traditional measurements such as time or distance profiles of individual chemical species, but it can also be directly interpreted in image form. This perspective offers an overview of flame chemistry and chemical kinetics measurements that combine tunable photoionization with multiple-mass detection, emphasizing the overall insight that can be gained from multidimensional data on these systems. The low-pressure flame apparatus is capable of providing isomer-resolved mass spectra of stable and radical species as a function of position in the flame. The overall chemical structure of the flames can be readily seen from images of the evolving mass spectrum as distance from the burner increases, with isomer-specific information given in images of the photoionization efficiency. Several flames are compared in this manner, with a focus on identification of global differences in fuel-decomposition and soot-formation pathways. Differences in the chemistry of flames of isomeric fuels can be discerned. The application of multiplexed synchrotron photoionization to elementary reaction kinetics permits identification of time-resolved isomeric composition in reacting systems. The power of this technique is illustrated by the separation of direct and dissociative ionization signals in the reaction of C2H5 with O2; by the resolution of isomeric products in reactions of the ethynyl (C2H) radical; and by preliminary observation of branching to methyl + propargyl products in the self-reaction of vinyl radicals. Finally, prospects for future research using multiplexed photoionization mass spectrometry are explored.

The SNF1-type serine-threonine protein kinase SAPK4 regulates stress-responsive gene expression in rice

Abstract: Plants respond to extracellularly perceived abiotic stresses such as low temperature, drought, and salinity by activation of complex intracellular signaling cascades that regulate acclimatory biochemical and physiological changes. Protein kinases are major signal transduction factors that have a central role in mediating acclimation to environmental changes in eukaryotic organisms. In this study, we characterized the function of the sucrose nonfermenting 1-related protein kinase2 (SnRK2) SAPK4 in the salt stress response of rice. Translational fusion of SAPK4 with the green fluorescent protein (GFP) showed subcellular localization in cytoplasm and nucleus. To examine the role of SAPK4 in salt tolerance we generated transgenic rice plants with over-expression of rice SAPK4 under control of the CaMV-35S promoter. Induced expression of SAPK4 resulted in improved germination, growth and development under salt stress both in seedlings and mature plants. In response to salt stress, the SAPK4-overexpressing rice accumulated less Na+ and Cl- and showed improved photosynthesis. SAPK4-regulated genes with functions in ion homeostasis and oxidative stress response were identified: the vacuolar H+-ATPase, the Na+/H+ antiporter NHX1, the Cl- channel OsCLC1 and a catalase. Our results show that SAPK4 regulates ion homeostasis and growth and development under salinity and suggest function of SAPK4 as a regulatory factor in plant salt stress acclimation. Identification of signaling elements involved in stress adaptation in plants presents a powerful approach to identify transcriptional activators of adaptive mechanisms to environmental changes that have the potential to improve tolerance in crop plants.

Non‐parametric small area estimation using penalized spline regression

Abstract: The paper proposes a small area estimation approach that combines small area random effects with a smooth, non-parametrically specified trend. By using penalized splines as the representation for the non-parametric trend, it is possible to express the non-parametric small area estimation problem as a mixed effect model regression. The resulting model is readily fitted by using existing model fitting approaches such as restricted maximum likelihood. We present theoretical results on the prediction mean-squared error of the estimator proposed and on likelihood ratio tests for random effects, and we propose a simple non-parametric bootstrap approach for model inference and estimation of the small area prediction mean-squared error. The applicability of the method is demonstrated on a survey of lakes in north-eastern USA.

Redox signal integration: from stimulus to networks and genes

Abstract: Recent research has established redox-dependent thiol modification of proteins as a major regulatory layer superimposed on most cell functional categories in plants. Modern proteomics and forward as well as reverse genetics approaches have enabled the identification of a high number of novel targets of redox regulation. Redox-controlled processes range from metabolism to transport, transcription and translation. Gene activity regulation by transcription factors such as TGA, Athb-9 and RAP2 directly or indirectly is controlled by the redox state. Knowledge on putative redox sensors such as the peroxiredoxins, on redox transmitters including thioredoxins and glutaredoxins and biochemical mechanisms of their linkage to the metabolic redox environment has emerged as the framework of a functional redox regulatory network. Its basic principle is similar in eukaryotic cells and particularly complex in the photosynthesizing chloroplast. Methods and knowledge are now at hand to develop a quantitative understanding of redox signalling and the redox regulatory network in the eukaryotic cell.