Activation of gene expression during hypersensitive response (HR) induced by auxin in the grapevine rootstock cultivar 'Börner'

The cultivar ‘Börner’ is one of the very few grape phylloxera (Daktulosphaira vitifoliae Fitch) resistant rootstocks commercially available. In contrast to tolerant or sensitive rootstocks, ‘Börner’ roots react to grape phylloxera attack with a hypersensitive response leading to necroses around the puncture sites. In this study, we identified genes differentially up-regulated during the HR. HR was chemically induced in root cells by the application of indol-acetic-acid (IAA). After a cDNA subtraction of induced and non-induced material, the subtracted cDNA-samples were also hybridized to Arabidopsis microarray chips to identify differentially expressed candidate genes. The microarray data were analyzed and differentially expressed genes were grouped into different functional categories, e.g. signal transduction pathways, transcription factors, defence associated genes. Primers were designed to target genes of interest putatively involved in the HR. So far, 38 ESTs induced in ‘Börner’ roots undergoing a HR have been sequenced and annotated.

Automatic Verification of Application-Tailored OSEK Kernels

The OSEK industrial standard governs the design of embedded real-time operating systems in the automotive domain. We report on efforts to develop verification methods for OSEK-conformant compilers, specifically of a code generator that weaves system calls and application code using a static configuration file, producing a stand-alone application that incorporates the relevant parts of the kernel. Our methodology involves two verification steps: On the one hand, we extract an OS-application interaction graph during the compilation phase and verify that it conforms to the standard, in particular regarding prioritized scheduling and interrupt handling. To this end, we generate from the configuration file a temporal specification of standard-conformant behaviour and model check the arising formulas on a labelled transition system extracted from the interaction graph. On the other hand, we verify that the actual generated code conforms to the interaction graph; this is done by graph isomorphism checking of the interaction graph against a dynamically-explored state-transition graph of the generated system

The hydrostatic control of load-induced height changes above subglacial Lake Vostok

Lake Vostok, East Antarctica, represents an extensive water surface at the base of the ice sheet. Snow, ice and atmospheric pressure loads applied anywhere within the lake area produce a hydrostatic response, involving deformations of the ice surface, ice–water interface and particle horizons. A modelling scheme is developed to derive height changes of these surfaces for a given load pattern. It is applied to a series of load scenarios, and predictions based on load fields derived from a regional climate model are compared to observational datasets. Our results show that surface height changes due to snow-buildup anomalies are damped over the lake area, reducing the spatial standard deviation by one-third. The response to air pressure variations, in turn, adds surface height variability. Atmospheric pressure loads may produce height changes of up to 4 cm at daily resolution, but decay rapidly with integration time. The hydrostatic load response has no significant impact neither on ICESat laser campaign biases determined over the lake area nor on vertical particle movements derived from GNSS observations

The hydrostatic control of load-induced height changes above subglacial Lake Vostok

Lake Vostok, East Antarctica, represents an extensive water surface at the base of the ice sheet. Snow, ice and atmospheric pressure loads applied anywhere within the lake area produce a hydrostatic response, involving deformations of the ice surface, ice-water interface and particle horizons. A modelling scheme is developed to derive height changes of these surfaces for a given load pattern. It is applied to a series of load scenarios, and predictions based on load fields derived from a regional climate model are compared to observational datasets. Our results show that surface height changes due to snow-buildup anomalies are damped over the lake area, reducing the spatial standard deviation by one-third. The response to air pressure variations, in turn, adds surface height variability. Atmospheric pressure loads may produce height changes of up to ±4 cm at daily resolution, but decay rapidly with integration time. The hydrostatic load response has no significant impact neither on ICESat laser campaign biases determined over the lake area nor on vertical particle movements derived from GNSS observations.Fil: Richter, Andreas Jorg. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata; Argentina. Universidad Nacional de la Plata. Facultad de Cs.astronomicas y Geofisicas. Laboratorio Maggia.; ArgentinaFil: Schröder, Ludwig. Technische Universität Dresden; AlemaniaFil: Scheinert, Mirko. Technische Universität Dresden; AlemaniaFil: Popov, Sergey V.. Polar Marine Geosurvey Expedition; Rusia. Saint Petersburg State University; RusiaFil: Groh, Andreas. Technische Universität Dresden; AlemaniaFil: Willen, Matthias. Technische Universität Dresden; AlemaniaFil: Horwath, Martin. Technische Universität Dresden; AlemaniaFil: Dietrich, Reinhard. Technische Universität Dresden; Alemani

Observed crustal uplift near the Southern Patagonian Icefield constrains improved viscoelastic Earth model

Thirty‒one GPS geodetic measurements of crustal uplift in southernmost South America determined extraordinarily high trend rates (> 35 mm/yr) in the north‒central part of the Southern Patagonian Icefield. These trends have a coherent pattern, motivating a refined viscoelastic glacial isostatic adjustment model to explain the observations. Two end‒member models provide good fits: both require a lithospheric thickness of 36.5 ± 5.3 km. However, one end‒member has a mantle viscosity near η =1.6 ×1018 Pa s and an ice collapse rate from the Little Ice Age (LIA) maximum comparable to a lowest recent estimate of 1995–2012 ice loss at about −11 Gt/yr. In contrast, the other end‒member has much larger viscosity: η = 8.0 ×1018 Pa s, half the post–LIA collapse rate, and a steadily rising loss rate in the twentieth century after AD 1943, reaching −25.9 Gt/yr during 1995–2012.Facultad de Ciencias Astronómicas y Geofísica

Four decades of Antarctic surface elevation changes from multi-mission satellite altimetry

We developed a multi-mission satellite altimetry analysis over the Antarctic Ice Sheet which comprises Seasat, Geosat, ERS-1, ERS-2, Envisat, ICESat and CryoSat-2. After a consistent reprocessing and a stepwise calibration of the inter-mission offsets, we obtained monthly grids of multi-mission surface elevation change (SEC) with respect to the reference epoch 09/2010 (in the format of month/year) from 1978 to 2017. A validation with independent elevation changes from in situ and airborne observations as well as a comparison with a firn model proves that the different missions and observation modes have been successfully combined to a seamless multi-mission time series. For coastal East Antarctica, even Seasat and Geosat provide reliable information and, hence, allow for the analysis of four decades of elevation changes. The spatial and temporal resolution of our result allows for the identification of when and where significant changes in elevation occurred. These time series add detailed information to the evolution of surface elevation in such key regions as Pine Island Glacier, Totten Glacier, Dronning Maud Land or Lake Vostok. After applying a density mask, we calculated time series of mass changes and found that the Antarctic Ice Sheet north of 81.5∘&thinsp;S was losing mass at an average rate of -85±16&thinsp;Gt&thinsp;yr−1 between 1992 and 2017, which accelerated to -137±25&thinsp;Gt&thinsp;yr−1 after 2010.</p

HESS Opinions: Functional units: a novel framework to explore the link between spatial organization and hydrological functioning of intermediate scale catchments

This opinion paper proposes a novel framework for exploring how spatial organization alongside with spatial heterogeneity controls functioning of intermediate scale catchments of organized complexity. Key idea is that spatial organization in landscapes implies that functioning of intermediate scale catchments is controlled by a hierarchy of functional units: hillslope scale lead topologies and embedded elementary functional units (EFUs). We argue that similar soils and vegetation communities and thus also soil structures "co-developed" within EFUs in an adaptive, self-organizing manner as they have been exposed to similar flows of energy, water and nutrients from the past to the present. Class members of the same EFU (class) are thus deemed to belong to the same ensemble with respect to controls of the energy balance and related vertical flows of capillary bounded soil water and heat. Class members of superordinate lead topologies are characterized by the same spatially organized arrangement of EFUs along the gradient driving lateral flows of free water as well as a similar surface and bedrock topography. We hence postulate that they belong to the same ensemble with respect to controls on rainfall runoff transformation and related vertical and lateral fluxes of free water. We expect class members of these functional units to have a distinct way how their architecture controls the interplay of state dynamics and integral flows, which is typical for all members of one class but dissimilar among the classes. This implies that we might infer on the typical dynamic behavior of the most important classes of EFU and lead topologies in a catchment, by thoroughly characterizing a few members of each class. A major asset of the proposed framework, which steps beyond the concept of hydrological response units, is that it can be tested experimentally. In this respect, we reflect on suitable strategies based on stratified observations drawing from process hydrology, soil physics, geophysics, ecology and remote sensing which are currently conducted in replicates of candidate functional units in the Attert basin (Luxembourg), to search for typical and similar functional and structural characteristics. A second asset of this framework is that it blueprints a way towards a structurally more adequate model concept for water and energy cycles in intermediate scale catchments, which balances necessary complexity with falsifiability. This is because EFU and lead topologies are deemed to mark a hierarchy of "scale breaks" where simplicity with respect to the energy balance and stream flow generation emerges from spatially organized process-structure interactions. This offers the opportunity for simplified descriptions of these processes that are nevertheless physically and thermodynamically consistent. In this respect we reflect on a candidate model structure that (a) may accommodate distributed observations of states and especially terrestrial controls on driving gradients to constrain the space of feasible model structures and (b) allows testing the possible added value of organizing principles to understand the role of spatial organization from an optimality perspective