Spin transport, spin diffusion and Bloch equations in electron storage rings

We show how, beginning with the Fokker--Planck equation for electrons emitting synchrotron radiation in a storage ring, the corresponding equation for spin motion can be constructed. This is an equation of the Bloch type for the polarisation density.Comment: 7 pages. No figures. Latex: Minor corrections in the tex

Toric K\"ahler metrics seen from infinity, quantization and compact tropical amoebas

We consider the metric space of all toric K\"ahler metrics on a compact toric manifold; when "looking at it from infinity" (following Gromov), we obtain the tangent cone at infinity, which is parametrized by equivalence classes of complete geodesics. In the present paper, we study the associated limit for the family of metrics on the toric variety, its quantization, and degeneration of generic divisors. The limits of the corresponding K\"ahler polarizations become degenerate along the Lagrangian fibration defined by the moment map. This allows us to interpolate continuously between geometric quantizations in the holomorphic and real polarizations and show that the monomial holomorphic sections of the prequantum bundle converge to Dirac delta distributions supported on Bohr-Sommerfeld fibers. In the second part, we use these families of toric metric degenerations to study the limit of compact hypersurface amoebas and show that in Legendre transformed variables they are described by tropical amoebas. We believe that our approach gives a different, complementary, perspective on the relation between complex algebraic geometry and tropical geometry.Comment: v1: 32 pages, 5 figures; v2: 1 figure added; v3: 1 reference added; v4: some reorganization, 1 theorem (now 1.1) added; v5: final version, to appear in JD

Using Model Predictive Control to Modulate the Humidity in a Broiler House and Effect on Energy Consumption

In moderate climate, broiler chicken houses are important heating energy consumers and hence heating fuel consumption accounts for a large part in operating costs. They can be reduced by constructional measures, which in turn lead to important costs as well. On the other hand, a software solution to reduce energy would lead to considerably less follow-up costs. The main objective of our work was to assess if it is possible to save energy with a software solution and eventually quantify the savings for a given broiler house in the Swiss Plateau. The investigation was carried out in simulation: the particular broiler house was measured, and a dynamical model for it was derived and validated. To actually search for a particular behaviour of the software that would lead to energy savings, model predictive control was used. The idea was not to specify a particular behaviour of the software but rather to let the software itself find the best behaviour in an exhaustive search. The simulations showed that energy savings can be realised mainly by letting the indoor humidity deviate from what usually is used as setpoint and hence take profit of the outdoor climate, which changes naturally during a 24-hour course. We used expert opinions to determine how long and large these setpoint deviations may be without harming the broilers. The simulations showed alsothat the light control and the biological activity of the animals reduced the potential savings

Bridging abstraction layers in process mining

While the maturity of process mining algorithms increases and more process mining tools enter the market, process mining projects still face the problem of different levels of abstraction when comparing events with modeled business activities. Current approaches for event log abstraction try to abstract from the events in an automated way that does not capture the required domain knowledge to fit business activities. This can lead to misinterpretation of discovered process models. We developed an approach that aims to abstract an event log to the same abstraction level that is needed by the business. We use domain knowledge extracted from existing process documentation to semi-automatically match events and activities. Our abstraction approach is able to deal with n:m relations between events and activities and also supports concurrency. We evaluated our approach in two case studies with a German IT outsourcing company

Cold priming on pathogen susceptibility in the Arabidopsis eds1 mutant background requires a functional stromal Ascorbate Peroxidase

24 h cold exposure (4°C) is sufficient to reduce pathogen susceptibility in Arabidopsis thaliana against the virulent Pseudomonas syringae pv. tomato (Pst) strain even when the infection occurs five days later. This priming effect is independent of the immune regulator Enhanced Disease Susceptibility 1 (EDS1) and can be observed in the immune-compromised eds1–2 null mutant. In contrast, cold priming-reduced Pst susceptibility is strongly impaired in knock-out lines of the stromal and thylakoid ascorbate peroxidases (sAPX/tAPX) highlighting their relevance for abiotic stress-related increased immune resilience. Here, we extended our analysis by generating an eds1 sapx double mutant. eds1 sapx showed eds1-like resistance and susceptibility phenotypes against Pst strains containing the effectors avrRPM1 and avrRPS4. In comparison to eds1–2, susceptibility against the wildtype Pst strain was constitutively enhanced in eds1 sapx. Although a prior cold priming exposure resulted in reduced Pst titers in eds1–2, it did not alter Pst resistance in eds1 sapx. This demonstrates that the genetic sAPX requirement for cold priming of basal plant immunity applies also to an eds1 null mutant background

In-depth investigations into Salmonella infection sources, reservoirs, and intervention measures in herds with a high hygiene level

The paper describes the in-depth analysis of the reasons for an extreme high Salmonella load of a high-health and well-managed pork production system and the measures that were taken to reduce the prevalence of Salmonella antibody positive finisher pigs produced by the system. The results and experiences gained during the study are discussed

Érasme traducteur

Érasme est le premier à traduire des tragédies grecques entières en latin. Les versions d’Euripide étaient pour lui des exercices propédeutiques pour son grand projet, la traduction du Nouveau Testament. Dans les lettres à William Warham, il nous informe sur sa méthode  : dans l’Hécube, il fournit une traduction vers à vers qui vise à imiter l’original d’une façon mimétique. Dans l’Iphigénie, Érasme a abandonné ce principe de mimésis, et traduit de manière plus détaillée. Il essaie d’atteindre les objectifs de l’original par des moyens de la langue cible et se sert d’une forme que l’on pourrait dénommer d’une notion de J.S. Holmes «  analogical form  ». Il est ainsi l’instigateur non seulement de la traduction littérale, mais aussi de celle littéraire.Erasmus has been the first translator of complete Greek tragedies into Latin. The translations from Euripides, although, were preparatory exercises for his main project, the translation of the New Testament. Along his correspondence with Willialm Warham, he exposes his method : in the Hecuba he opted for a line-to-line translation, reproducing each line mimetically. In the Iphigenia he abandoned the idea of mimesis and translated in a more detailed way. He tried to reproduce the original purposes into the translating language, forestalling the notion of “analogical form” by J.S. Holmes. He is thus the instigator not only of the literal translation, but also of the literary one

On finitely ambiguous B\"uchi automata

Unambiguous B\"uchi automata, i.e. B\"uchi automata allowing only one accepting run per word, are a useful restriction of B\"uchi automata that is well-suited for probabilistic model-checking. In this paper we propose a more permissive variant, namely finitely ambiguous B\"uchi automata, a generalisation where each word has at most $k$ accepting runs, for some fixed $k$. We adapt existing notions and results concerning finite and bounded ambiguity of finite automata to the setting of $\omega$-languages and present a translation from arbitrary nondeterministic B\"uchi automata with $n$ states to finitely ambiguous automata with at most $3^n$ states and at most $n$ accepting runs per word

Edge minimization in de Bruijn graphs

This paper introduces the de Bruijn graph edge minimization problem, which is related to the compression of de Bruijn graphs: find the order-k de Bruijn graph with minimum edge count among all orders. We describe an efficient algorithm that solves this problem. Since the edge minimization problem is connected to the BWT compression technique called "tunneling", the paper also describes a way to minimize the length of a tunneled BWT in such a way that useful properties for sequence analysis are preserved. Although being a restriction, this is significant progress towards a solution to the open problem of finding optimal disjoint blocks that minimize space, as stated in Alanko et al. (DCC 2019).Comment: Accepted for Data Compression Conference 202

FRASHER – A framework for automated evaluation of similarity hashing

A challenge for digital forensic investigations is dealing with large amounts of data that need to be processed. Approximate matching (AM), a.k.a. similarity hashing or fuzzy hashing, plays a pivotal role in solving this challenge. Many algorithms have been proposed over the years such as ssdeep, sdhash, MRSH-v2, or TLSH, which can be used for similarity assessment, clustering of different artifacts, or finding fragments and embedded objects. To assess the differences between these implementations (e.g., in terms of runtime efficiency, fragment detection, or resistance against obfuscation attacks), a testing framework is indispensable and the core of this article. The proposed framework is called FRASHER (referring to a predecessor FRASH from 2013) and provides an up-to-date view on the problem of evaluating AM algorithms with respect to both the conceptual and the practical aspects. Consequently, we present and discuss relevant test case scenarios as well as release and demonstrate our framework allowing a comprehensive evaluation of AM algorithms. Compared to its predecessor, we adapt it to a modern environment providing better modularity and usability as well as more thorough testing cases