The values of unipotent characters at unipotent elements for groups of type E8E_8 and 2 ⁣E6{^2\!E}_6

In order to tackle the problem of generically determining the character tables of the finite groups of Lie type $\mathbf{G}(q)$ associated to a connected reductive group $\mathbf{G}$ over $\overline{\mathbb F}_p$, Lusztig developed the theory of character sheaves in the 1980s. The subsequent work of Lusztig and Shoji in principle reduces this problem to specifying certain roots of unity. The situation is particularly well understood as far as character values at unipotent elements are concerned. We complete the computation of the values of unipotent characters at unipotent elements for the groups $\mathbf{G}(q)$ where $\mathbf{G}$ is the simple group of type $E_8$, by specifying the aforementioned roots of unity for all prime powers $q$. We also resolve this task for the groups ${^2\!E}_6(q)$ when $q$ is a power of $p=2$. Our results thus conclude the project of computing the values of unipotent characters at unipotent elements for the simple exceptional groups of Lie type.Comment: 39 pages; added section on groups of twisted type E6 and adjusted title, abstract and introduction accordingl

Integration of Time Lapse Seismic Data Using Onset Time and Analysis of Spatial Resolution

Integration of time-lapse seismic data into the reservoir model offers great potential in understanding reservoir flow patterns as well as reservoir properties. However, it also requires the solution of an inverse problem, which poses challenges in terms of dynamic reservoir modeling and seismic history matching to infer reservoir characterization. In this dissertation, we first present a method for assessing the inversion results in underdetermined problems, resulting in a multi scale data integration, Then, we introduce a novel history matching approach to integrate frequent seismic surveys (4D) using onset times. In the first part, an analysis of spatial resolution is incorporated into an efficient history matching approach, in order to indicate the reliability of the estimated solution. By examining the spatial resolution in seismic data integration, as a function of derivation type, we evaluate quantitatively the contribution of pressure and saturation changes on the calibrated permeability field. Next, we present a novel and efficient approach to integrate frequent time lapse (4D) seismic data into high resolution reservoir models based on seismic onset times. Our approach reduces multiple time-lapse seismic survey data into a single map of onset times, leading to substantial data reduction for history matching while capturing all relevant information regarding fluid flow in the reservoir. We demonstrate the practical feasibility of our proposed approach through the heavy oil reservoir at Pad 31 in the Peace River Field (Alberta, Canada) with daily time lapse seismic surveys recorded by a permanently buried seismic monitoring system. Finally, we quantitatively investigate the effectiveness of the onset time and the amplitude inversion to solve the inverse problem associated with integrating 4D seismic data into the reservoir model. The results of the study demonstrate the effectiveness of the onset time approach for integrating a large number of seismic surveys by compressing them into a single map. Also, the onset times appear to be relatively insensitive to the petro elastic model but sensitive to the steam/fluid propagation, making it a robust method for history matching of time lapse surveys

Community structure, ecophysiology, and regulation of new, acid-tolerant denitrifiers as cause of high N2O emissions from cryoturbated peat circles of acidic tundra soils

Denitrification is the main source of N2O emissions from cryoturbated peat circles in the Eastern European Arctic tundra. These permafrost-affected bare peat circles lack vegetation, have a high amount of available nitrate, and a low carbon to nitrogen ratio. Together with a soil moisture of ~ 70%, these are optimum conditions for denitrification and associated microorganisms. An acidic in situ pH of these peat circles is hypothesized to be a major controlling factor influencing denitrification and triggering the release of N2O as emitted end product of denitrification, as the final enzymatic step of denitrification is impaired by a low pH. This thesis aimed to test if the ecophysiology of new and acid-tolerant denitrifiers affects the emissions of N2O from cryoturbated peat circles. Microcosm experiments with soil from bare peat circles and surrounding vegetated peat plateau were conducted to test denitrification potentials of both soils. Additionally, the influence of pH on denitrification was tested. Nitrate reduction and associated production of gaseous N-products by denitrification were detected in both soils. In peat circle soil microcosms, independent of pH, the released end product was N2. Though nitrate reduction was slower at pH 4. In peat plateau microcosms N 2 was as well the emitted main end product at pH 6, whereas at pH 4 N2O was emitted. Therefore, data indicate the potential for denitrification in both soil types, as well as complete denitrification potential at acidic pH in peat circles. Microcosms experiments supplemented with labeled acetate were conducted to reveal the active, organic acid utilizing archaeal and bacterial community of denitrifiers based on 16S rRNA stable isotope probing coupled to Illumina MiSeq amplicon sequencing. Results suggest Burkholderiaceae as key nitrate reducers and acetate assimilators. This is supported by a new species within the Burkholderiaceae (Caballeronia) isolated from peat circle soil that encodes diverse nitrate and nitrite reductases. Potential key denitrifiers responsible for the reduction of N2O to N2, the detected end product and product of complete denitrification, are Sphingobacteriacea. Altogether, collected data suggest an electron donor limitation in peat circle soil leading to high in situ emission of N2O, since peat circle soil demonstrated the potential for complete denitrification despite an acidic pH

ON THE VALUES OF UNIPOTENT CHARACTERS OF FINITE CHEVALLEY GROUPS OF TYPE E_7 IN CHARACTERISTIC 2

Let G be a finite group of Lie type. In order to determine the character table of G, Lusztig developed the theory of character sheaves. In this framework, one has to find the transformation between two bases for the space of class functions on G, one of them being the irreducible characters of G, the other one consisting of characteristic functions associated to character sheaves. In principle, this has been achieved by Lusztig and Shoji, but the underlying process involves some scalars which are still unknown in many cases. The problem of specifying these scalars can be reduced to considering cuspidal character sheaves. We will deal with the latter for the specific case where G = E_7(q), and q is a power of the bad prime p = 2 for E_7

Acerca de la estructura y frecuencias de las oraciones compuestas en textos españoles especializados

Tal como en trabajos anteriores relativos al contraste gramatical español-alemán y al empleo de realia en ambas lenguas, a la estructura y relaciones de frecuencia de su núcleo verbal, a las capas y frecuencias de su léxico especializado y literario, a la formación, así como a la variabilidad de sus términos sintagmáticos, el presente artículo se basa en el corpus reunido entre 1982 y 2002 con activa participación de los estudiantes del Seminario de Traducción e Interpretación de la Facultad de Filología Moderna de la Universidad de Heidelberg. En este caso resumimos, respetándolos rigurosamente, elaboramos en forma de artículo y formulamos en lengua española los resultados de una tesina de diplomatura (Hetz 1987) realizada bajo nuestra dirección y sobre la base de nuestro método de análisis. Es pues de estricta y merecida justicia incluir el nombre de Robert Hetz en calidad de coautor del trabajo

THEME SERIES - UPR in Cancer

International audienceOver the past decade endoplasmic reticulum (ER) stress signaling pathways have collectively emerged as an essential mechanism at the crossroads of the cellular functions involved in key steps of cancer development. ER stress signaling has pleiotropic roles in cancer, and is involved at the level of cell transformation, tumor growth and metastasis as well as resistance to chemo- and radio-therapy. Indeed beyond the instrumental roles of the ER in the biogenesis of secretory and transmembrane proteins..

A General Spatio-Temporal Clustering-Based Non-local Formulation for Multiscale Modeling of Compartmentalized Reservoirs

Representing the reservoir as a network of discrete compartments with neighbor and non-neighbor connections is a fast, yet accurate method for analyzing oil and gas reservoirs. Automatic and rapid detection of coarse-scale compartments with distinct static and dynamic properties is an integral part of such high-level reservoir analysis. In this work, we present a hybrid framework specific to reservoir analysis for an automatic detection of clusters in space using spatial and temporal field data, coupled with a physics-based multiscale modeling approach. In this work a novel hybrid approach is presented in which we couple a physics-based non-local modeling framework with data-driven clustering techniques to provide a fast and accurate multiscale modeling of compartmentalized reservoirs. This research also adds to the literature by presenting a comprehensive work on spatio-temporal clustering for reservoir studies applications that well considers the clustering complexities, the intrinsic sparse and noisy nature of the data, and the interpretability of the outcome. Keywords: Artificial Intelligence; Machine Learning; Spatio-Temporal Clustering; Physics-Based Data-Driven Formulation; Multiscale Modelin

On the labelling of characters of Weyl groups of type F4F_4

In the literature on finite groups of Lie type, there exist two different conventions about the labelling of the irreducible characters of Weyl groups of type~$F_4$. We point out some issues concerning these two conventions and their effect on tables about unipotent characters or the Springer correspondence. Using experiments related to these issues with the computer algebra system {\sf CHEVIE}, we spotted an error in Spaltenstein's tables for the generalised Springer correspondence in type~$E_7$.Comment: 12 pages; substantial revision, several corrections and one additio