Brassinosteroiders roll i stimulering av tillväxt och stress tolerans hos växter efter priming med nyttiga bakterier

Brassinosteroids (BR) are plant hormones widely distributed throughout the plant kingdom in low concentrations and with structural homology to animal and insect steroids. BR are involved in numerous physiological processes, and they also fulfill an antagonistic role in anti-herbivory structure formation in tomato (Campos et al., 2009). In order to characterize the role of BR upon priming with B. amyloliquefasciens 5113, gene expression analysis of BR genes was assessed in Arabidopsis thaliana. BAK1, BRI1 and DWF1 expression down-regulates, while DET2 upregulates upon bacterial priming. CPD gene expression was not affected by priming. qPCR analysis of VSP2 and PR1 were performed on BR mutants upon priming with B. amyloliquefasciens 5113. Basal levels of PR1 were higher in det2, bak1 and dwf1 compared to primed samples. Primed bri1 displayed two-fold higher expression of PR1 compared to untreated bri1. VSP2 level goes up on det2, bak1 and bri1 upon priming. No changes of VSP2 expression were observed in dwf1 upon priming. Methyl jasmonate treatment up-regulates VSP2 level twofold in det2 and nine-fold in bak1. The role of BR genes in response to insect attack was examined. BR genes appear not to be responsive to herbivory by S. littoralis. However, S. littoralis larvae fed more on BR mutants compared to those that fed on Col-0 WT. In order to understand the role of BR in JA signaling pTRV-JAR1 and pTRV-LOX2 constructs were developed and virus induced gene silencing were performed on Col-0 and BR mutants bak1 and det2. Gene silencing was confirmed by qPCR analysis of the target genes in Col-0 and det2, but not in bak1. Further insect feeding experiments are required to elucidate if BR play a role in defense responses to herbivory when JA signaling pathway is compromised

Time-domain scars: resolving the spectral form factor in phase space

We study the relationship of the spectral form factor with quantum as well as classical probabilities to return. Defining a quantum return probability in phase space as a trace over the propagator of the Wigner function allows us to identify and resolve manifolds in phase space that contribute to the form factor. They can be associated to classical invariant manifolds such as periodic orbits, but also to non-classical structures like sets of midpoints between periodic points. By contrast to scars in wavefunctions, these features are not subject to the uncertainty relation and therefore need not show any smearing. They constitute important exceptions from a continuous convergence in the classical limit of the Wigner towards the Liouville propagator. We support our theory with numerical results for the quantum cat map and the harmonically driven quartic oscillator.Comment: 10 pages, 4 figure

Random Graphs Associated to some Discrete and Continuous Time Preferential Attachment Models

We give a common description of Simon, Barab\'asi--Albert, II-PA and Price growth models, by introducing suitable random graph processes with preferential attachment mechanisms. Through the II-PA model, we prove the conditions for which the asymptotic degree distribution of the Barab\'asi--Albert model coincides with the asymptotic in-degree distribution of the Simon model. Furthermore, we show that when the number of vertices in the Simon model (with parameter $\alpha$) goes to infinity, a portion of them behave as a Yule model with parameters $(\lambda,\beta) = (1-\alpha,1)$, and through this relation we explain why asymptotic properties of a random vertex in Simon model, coincide with the asymptotic properties of a random genus in Yule model. As a by-product of our analysis, we prove the explicit expression of the in-degree distribution for the II-PA model, given without proof in \cite{Newman2005}. References to traditional and recent applications of the these models are also discussed

Bringing entanglement to the high temperature limit

We show the existence of an entangled nonequilibrium state at very high temperatures when two linearly coupled harmonic oscillators are parametrically driven and dissipate into two independent heat baths. This result has a twofold meaning: first, it fundamentally shifts the classical-quantum border to temperatures as high as our experimental ability allows us, and second, it can help increase by at least one order of magnitude the temperature at which current experimental setups are operated.Comment: accepted in Phys. Rev. Let

Addressing organisational and societal concerns : an application of critical systems thinking to information systems planning in Colombia

Most current information system s (IS) planning methodologies are focused on achieving ‘successful’ plans, i.e. plans that provide competitive advantage, can be implemented in a given period of time, and that solve the problems of information needs by taking advantage of the latest technologies available. Concerns are technology and business driven, and focus on how to get the maximum profit for organisations from investing in information systems. However, this relatively narrow focus can be problematic, especially in developing countries where the social contexts of IS implementation may require a different primary focus. This chapter presents a methodology for IS planning based on critical systems thinking – an approach that encourages the critical analysis of stake holder understandings of social contexts prior to the selection and/ or design of planning methods. The methodology presented in this chapter uses a combination of the systems theories of autopoiesis and boundary critiques, which deepen our understanding of what it means to reflect on participation, values and social concerns during IS planning. In the course of applying the methodology in a project in Colombia, an issue arose of the ethics of the practitioner. To address this issue, following completion of the project, we sought to enhance critical systems thinking with Foucault ’s notions of power and ethics, which offer interesting alternatives for practitioner self-reflection. Implications for IS planning are derived from this perspective on ethics and power