Tobias Berger - Independent Researcher (original) (raw)

Papers by Tobias Berger

High fluoride concentrations in surface water : example from a catchment in SE Sweden

{ell}-adic Representations Associated to Modular Forms over Imaginary Quadratic Fields

International Mathematics Research Notices, 2007

Meeting Future Customer and Quality Requirements with a Multi-sited

Submitted by Tobias Berger Matr.No. 31471 Information and Media Technology tobias.berger@tuhh.de ... more Submitted by Tobias Berger Matr.No. 31471 Information and Media Technology tobias.berger@tuhh.de ... Supervised by Hamburg University of Technology STS – Institute for Software Systems Prof. Dr. Joachim W. Schmidt Sebastian Bossung Vattenfall Europe ...

On Lifting and Modularity of Reducible Residual Galois Representations Over Imaginary Quadratic Fields

International Mathematics Research Notices, 2015

What do population viability analyses tell about the future for Baltic Dunlin Calidris alpina schinzii and Montagu’s Harrier Circus pygargus on Öland?

Ornis Svecica

Population viability analysis (PVA) has become an important tool in conservation biology. Even th... more Population viability analysis (PVA) has become an important tool in conservation biology. Even though detailed outcomes of PVA: s are constrained by data quality, it is a useful approach when the objective is exploratory, aiming to identify important parameters for ...

A probabilistic view of risks associated with consumption of drinking water in an area with natural fluoride enrichments

Probabilistic exposure assessment challenges the safety margin in drinking water criteria – the example of fluoride

Assessing the risk of an excessive fluoride intake in a region of southeastern Sweden

Theta lifts of Bianchi modular forms and applications to paramodularity

Journal of the London Mathematical Society, 2015

Chemical Geology, 2015

The impact of fluoride on the abundance and speciation of aluminium (Al) was investigated in thre... more The impact of fluoride on the abundance and speciation of aluminium (Al) was investigated in three boreal streams characterised by overall high concentrations of fluoride and dissolved organic matter. Stream-water sampling was carried out several times a year for at least four years, and a chemical equilibrium model (Visual MINTEQ) was applied in order to model the proportion of colloidal and organically/inorganically complexed Al in the waters. The Al concentrations in filtered (0.45 µm) water samples were inversely correlated with pH, and reached values up to approximately 1 mg/L during low pH conditions (pH < 6.0). In a stream with high fluoride concentrations, as compared to a similar stream with only moderately elevated fluoride concentrations, the Al concentrations were consistently elevated. For the stream with high concentrations of fluoride and Al, the model predicted both high concentrations and proportions of Al-fluoride complexation. This prediction indicates that high fluoride levels contribute to raise both the Al abundance and the ratio of inorganic to organic Al complexation in stream water. In contrast, for another stream with high fluoride concentrations and consistently high (near neutral) pH, there was no evidence of fluoride affecting Al concentration or complexation. These results show that it is important to focus future studies on the role of high levels of dissolved fluoride on both the speciation and the toxicity of Al in stream water. Abbreviations: Al 0.45 = Analytical data of aluminium after filtration by a 0.45 µm pore size membrane filter (i.e., excluding particulate Al) Al c = Modelled inorganic colloidal aluminium, i.e., the proportion of Al 0.45 occurring as Al(OH) 3 (s) Al i = Modelled inorganic monomeric aluminium, i.e., the sum of aquo, hydroxy and other inorganically complexed forms Al i-F = Modelled fluoride-complexed aluminium Al o = Modelled organically complexed aluminium Al d = Modelled dissolved aluminium, i.e., Al i + Al o (all dissolved Al species are listed in Tables A2-A3, Appendix A)

Workshop on OWL: Experiences and Directions, 2007

We argue for the usefulness of convenient optimization criteria, when building scalable and ecien... more We argue for the usefulness of convenient optimization criteria, when building scalable and ecient instance retrieval inference services for ontology-based applications. We discuss several optimization criteria, especially a dedicated load balancing strategy, evaluate the approach with practical ex- periments on a particular implementation and present results.

Mathematical Research Letters, 2014

We prove a commutative algebra result which has consequences for congruences between automorphic ... more We prove a commutative algebra result which has consequences for congruences between automorphic forms modulo prime powers. If C denotes the congruence module for a fixed automorphic Hecke eigenform π 0 we prove an exact relation between the p-adic valuation of the order of C and the sum of the exponents of p-power congruences between the Hecke eigenvalues of π 0 and other automorphic forms. We apply this result to several situations including the congruences described by Mazur's Eisenstein ideal.

Aluminium speciation in boreal catchments enriched in fluoride

Beton- und Stahlbetonbau, 2005

Die neue Hauptverwaltung der Lufthansa AG in Frankfurt am Main weist eine modulare Gebäudestruktu... more Die neue Hauptverwaltung der Lufthansa AG in Frankfurt am Main weist eine modulare Gebäudestruktur auf. In einem ersten Bauabschnitt entstehen zehn Gebäudefinger mit dazwischen liegenden Atrien für 1650 Arbeitsplätze (Bild 1). Die Finger sitzen auf einer gemeinsamen Tiefgarage mit drei Untergeschossen und einem darunter liegendem Medienkanal; sie haben bis zu sieben Obergeschosse. Die kammartige Gebäudestruktur erlaubt die Ausbildung von transparenten Atrien. Diese Gartenhöfe dienen als Schall-und Immissionspuffer und ermöglichen gleichzeitig eine natürli-che Belichtung und Belüftung der Büroflächen. Die Grundabmessungen des ersten Bauabschnittes sind ca. 90 m × 175 m. Das Gebäude ist mit doppelt gekrümmten Stahlbetonschalen über den Bürofingern und doppelt gekrümmten Stahlgitterschalen über den Atrien überdacht. Die Schalenformen mit den jeweils sehr geringen Stichmaßen sind an die Flügelform eines Kranichs angelehnt, das Signet der Lufthansa AG. 2 Tragwerk der Stahlbetondachschalen Die doppelt gekrümmten Dachelemente aus Stahlbeton sind als ton-nenartige Schale ausgeführt (Bild 2). Sie sind in Längsrichtung ca. 42 m lang und verjüngen sich von der Gebäudeinnenseite zur Giebelseite hin von 16,50 m auf 12,80 m. Das mittlere Stichmaß liegt bei 1,65 m. Die vertikale Lagerung der Schalen erfolgt seitlich auf Randunterzügen (die wiederum die Lasten in Stahlbetonstützen weiterleiten) sowie im hinteren Drittel exzentrisch zur Schalenachse auf Kernwänden. Die Dicke der Schale beträgt 28 cm mit 3 cm tiefen oberseitigen Schlitzen im Abstand von 2,70 m über der gesamten Schalenbreite. Da das mittlere Stichmaß von 1,65 m bei einer mittleren Spannweite von 14,50 m sehr gering ist, wurde die Biegesteifigkeit der Schale durch Überzüge mit einem Achsabstand von 2,70 m vergrößert (Bild 3). Im Zusammenspiel mit einer Vorspannung mit Monolitzen wurde das Schalentragverhalten aktiviert. In der Schale verlaufen zudem zahlreiche Installationsleitungen der Haustechnik sowie eine Bauteilaktivierung (Bild 4). Seitlich auf den Randunterzügen der Stahlbetonschalen lagern die Glas-Stahl-Schalen auf. Im Bereich der Giebelstützen erfolgt die Anlenkung der

Einsparung von Grauer Energie bei Hochhäusern

Beton- und Stahlbetonbau, 2013

Fluoride patterns in a boreal stream influenced by bedrock and hydrology

… Magazine, Vol. 75 (3), 2011

lnu.se. Publications. ...

Mathematische Annalen, 2011

We prove the modularity of certain residually reducible p-adic Galois representations of an imagi... more We prove the modularity of certain residually reducible p-adic Galois representations of an imaginary quadratic field assuming the uniqueness of the residual representation. We obtain an R = T theorem using a new commutative algebra criterion that might be of independent interest. To apply the criterion, one needs to show that the quotient of the universal deformation ring R by its ideal of reducibility is cyclic Artinian of order no greater than the order of the congruence module T/J , where J is an Eisenstein ideal in the local Hecke algebra T. The inequality is proven by applying the Main conjecture of Iwasawa Theory for Hecke characters and using a result of Berger [Compos Math 145(3):603-632, 2009]. This strengthens our previous result [Berger and Klosin, J Inst Math Jussieu 8(4):669 -692, 2009] to include the cases of an arbitrary p-adic valuation of the L-value, in particular, cases when R is not a discrete valuation ring. As a consequence we show that the Eisenstein ideal is principal and that T is a complete intersection.

Mathematische Annalen, 2013

We study the crystalline universal deformation ring R (and its ideal of reducibility I) of a mod ... more We study the crystalline universal deformation ring R (and its ideal of reducibility I) of a mod p Galois representation ρ 0 of dimension n whose semisimplification is the direct sum of two absolutely irreducible mutually non-isomorphic constituents ρ 1 and ρ 2 . Under some assumptions on Selmer groups associated with ρ 1 and ρ 2 we show that R/I is cyclic and often finite. Using ideas and results of (but somewhat different assumptions from) Bellaïche and Chenevier we prove that I is principal for essentially self-dual representations and deduce statements about the structure of R. Using a new commutative algebra criterion we show that given enough information on the Hecke side one gets an R = T -theorem. We then apply the technique to modularity problems for 2-dimensional representations over an imaginary quadratic field and a 4-dimensional representation over Q.

Journal of the Institute of Mathematics of Jussieu, 2009

We prove the modularity of minimally ramified ordinary residually reducible p-adic Galois represe... more We prove the modularity of minimally ramified ordinary residually reducible p-adic Galois representations of an imaginary quadratic field F under certain assumptions. We first exhibit conditions under which the residual representation is unique up to isomorphism. Then we prove the existence of deformations arising from cuspforms on GL 2 (A F ) via the Galois representations constructed by Taylor et al. We establish a sufficient condition (in terms of the non-existence of certain field extensions which in many cases can be reduced to a condition on an L-value) for the universal deformation ring to be a discrete valuation ring and in that case we prove an R = T theorem. We also study reducible deformations and show that no minimal characteristic 0 reducible deformation exists.

Inventiones Mathematicae, 1993

Let π be a regular algebraic cuspidal automorphic representation of GL 2 over an imaginary quadra... more Let π be a regular algebraic cuspidal automorphic representation of GL 2 over an imaginary quadratic number field K, and let ℓ be a prime number. Assuming the central character of π is invariant under the non-trivial automorphism of K, it is shown that there is a continuous irreducible ℓ-adic representation ρ of Gal(K/K) such that L(s, ρv) = L(s, πv) whenever v is a prime of K outside an explicit finite set.