Checking Presence Reachability Properties on Parameterized Shared-Memory Systems

We consider the verification of distributed systems composed of an arbitrary number of asynchronous processes. Processes are identical finite-state machines that communicate by reading from and writing to a shared memory. Beyond the standard model with finitely many registers, we tackle round-based shared-memory systems with fresh registers at each round. In the latter model, both the number of processes and the number of registers are unbounded, making verification particularly challenging. The properties studied are generic presence reachability objectives, which subsume classical questions such as safety or synchronization by expressing the presence or absence of processes in some states. In the more general round-based setting, we establish that the parameterized verification of presence reachability properties is PSPACE-complete. Moreover, for the roundless model with finitely many registers, we prove that the complexity drops down to NP-complete and we provide several natural restrictions that make the problem solvable in polynomial time

Greater Swahili – Swahili Varieties in L2+ Swahili Teaching

In this paper, I focus on what we could call the ‘myth of Standard Swahili’ and its consequences for language teaching. Instead of distinguishing between ‘standard’ and ‘deviant’ varieties of Swahili, I suggest the term Greater Swahili to designate the whole of the varieties spoken in Africa and the African diaspora. Starting with some remarks on the ‘ideal’ Swahili speaker and the standardization of Swahili (a thoroughly political decision), this paper focuses on the challenge of using a Standard for teaching while language learners will meet mostly speakers of Greater Swahili. The diversity in the ways of speaking is not only a challenge for language teachers and learners, but also for speakers of the so-called core area. I will then discuss some examples to illustrate acceptance and comprehension of Greater Swahili by L2+ Swahili students. May aim is to underline the importance of Greater Swahili varieties for Swahili Studies

Chesterton, modernism, and the representation of reality

Includes bibliographical references.This dissertation seeks to demonstrate and propose a resolution to modernism in the form of the thought and literature of GK Chesterton. Chesterton, whilst constantly touted as either a harmless kind of literary clown or as a Christian crypto-fascist, has largely been ignored within all serious academic discourse. Therefore, the work of this dissertation takes place in three, interconnected and inter-weaved, stages. Firstly, the core of modernism – its problems, inconsistencies, and political ramifications - is elucidated; secondly, the central ideas of Chesterton's work are explored; and, finally, the way in which Chesterton's work presents a viable resolution to modernism's problems, is explained. In this explanation, I propose an academic return to Chesterton as a serious and coherent counter-voice to the literature of canonical high modernism. At the heart of this thesis is the presupposition that the primal energy of modernism stems from the crisis of representation - the doubt that any reality, other than that which is subjective, can ever be known or represented. I suggest that this turn towards subjectivity exposed the modern world firstly to a kind of negative liberalism that tends to dehumanise politics, and secondly to an authoritarianism that enlarges the subjective to grand proportions in a bid to include absolutely everything into its ambit. Chesterton's thought counters such scepticism with his faith in the coherence and goodness of Being, and the organic participation of Mind and language within that Being. In his opposition to scepticism, Chesterton proposes an allegorical view of literature that has at its heart a belief in the priestly nature of writing and its ability to transfigure language into an allegory of reality. Not only is this a mere counter, but I argue that it becomes an attempt to reposition modernism itself within a scheme of Being, so as to re-configure its sceptical nature as a necessary pre- which offers a kind of sacred humanism as the new centre for a liberalism that is neither totalitarian nor relativist, but rather democratic in its proposal of an objective reality accessible to all people. In Chesterton’s vista, the artist is reduced from modernist master to servant of reality. My thesis works along the theoretical lines proposed by figures such as Erich Auerbach and Pericles Lewis in their analysis of mimesis and modernism in the Western canon, as well as, in particular, Lewis's theorising of the political nature of the modernist novel, in its bid to intervene upon the liberal crisis of subjectivity and thus pre-empt an organic totalitarianism. Overarching such theoretical underpinnings, however, is an analysis of Chesterton's deployment of Thomas Aquinas, and the way in which Chesterton approaches Thomism as the philosophical means by which he attempts to unite the literal graphics of writing with metaphysical reality. In so doing, this dissertation argues that Chesterton charts a way beyond both modernism and anti-modernism toward a new kind of literary sublimity that is able to incarnate objective reality

Checking Presence Reachability Properties on Parameterized Shared-Memory Systems

We consider the verification of distributed systems composed of an arbitrary number of asynchronous processes. Processes are identical finite-state machines that communicate by reading from and writing to a shared memory. Beyond the standard model with finitely many registers, we tackle round-based shared-memory systems with fresh registers at each round. In the latter model, both the number of processes and the number of registers are unbounded, making verification particularly challenging. The properties studied are generic presence reachability objectives, which subsume classical questions such as safety or synchronization by expressing the presence or absence of processes in some states. In the more general round-based setting, we establish that the parameterized verification of presence reachability properties is PSPACE-complete. Moreover, for the roundless model with finitely many registers, we prove that the complexity drops down to NP-complete and we provide several natural restrictions that make the problem solvable in polynomial time.Comment: 27 pages, 6 figure

Robust artifactual independent component classification for BCI practitioners

Objective. EEG artifacts of non-neural origin can be separated from neural signals by independent component analysis (ICA). It is unclear (1) how robustly recently proposed artifact classifiers transfer to novel users, novel paradigms or changed electrode setups, and (2) how artifact cleaning by a machine learning classifier impacts the performance of brain–computer interfaces (BCIs). Approach. Addressing (1), the robustness of different strategies with respect to the transfer between paradigms and electrode setups of a recently proposed classifier is investigated on offline data from 35 users and 3 EEG paradigms, which contain 6303 expert-labeled components from two ICA and preprocessing variants. Addressing (2), the effect of artifact removal on single-trial BCI classification is estimated on BCI trials from 101 users and 3 paradigms. Main results. We show that (1) the proposed artifact classifier generalizes to completely different EEG paradigms. To obtain similar results under massively reduced electrode setups, a proposed novel strategy improves artifact classification. Addressing (2), ICA artifact cleaning has little influence on average BCI performance when analyzed by state-of-the-art BCI methods. When slow motor-related features are exploited, performance varies strongly between individuals, as artifacts may obstruct relevant neural activity or are inadvertently used for BCI control. Significance. Robustness of the proposed strategies can be reproduced by EEG practitioners as the method is made available as an EEGLAB plug-in.EC/FP7/224631/EU/Tools for Brain-Computer Interaction/TOBIBMBF, 01GQ0850, Verbundprojekt: Bernstein Fokus Neurotechnologie - Nichtinvasive Neurotechnologie für Mensch-Maschine Interaktion - Teilprojekte A1, A3, A4, B4, W3, ZentrumDFG, 194657344, EXC 1086: BrainLinks-BrainTool

Bioprocess Development for Lantibiotic Ruminococcin-A Production in Escherichia coli and Kinetic Insights Into LanM Enzymes Catalysis

Ruminococcin-A (RumA) is a peptide antibiotic with post-translational modifications including thioether cross-links formed from non-canonical amino acids, called lanthionines, synthesized by a dedicated lanthionine-generating enzyme RumM. RumA is naturally produced by Ruminococcus gnavus, which is part of the normal bacterial flora in the human gut. High activity of RumA against pathogenic Clostridia has been reported, thus allowing potential exploitation of RumA for clinical applications. However, purifying RumA from R. gnavus is challenging due to low production yields (120 mg L–1 for the chimeric construct and >150 mg L–1 for RumM. The correlation observed between microscale and lab-scale bioreactor cultivations suggests that the process is robust and realistically applicable to industrial-scale conditions.DFG, 53182490, EXC 314: Unifying Concepts in CatalysisDFG, 414044773, Open Access Publizieren 2019 - 2020 / Technische Universität Berli

Garden of therapeutic delights: new targets in rheumatic diseases

Advances in our understanding of the cellular and molecular mechanisms in rheumatic disease fostered the advent of the targeted therapeutics era. Intense research activity continues to increase the number of potential targets at an accelerated pace. In this review, examples of promising targets and agents that are at various stages of clinical development are described. Cytokine inhibition remains at the forefront with the success of tumor necrosis factor blockers, and biologics that block interleukin-6 (IL-6), IL-17, IL-12, and IL-23 and other cytokines are on the horizon. After the success of rituximab and abatacept, other cell-targeted approaches that inhibit or deplete lymphocytes have moved forward, such as blocking BAFF/BLyS (B-cell activation factor of the tumor necrosis factor family/B-lymphocyte stimulator) and APRIL (a proliferation-inducing ligand) or suppressing T-cell activation with costimulation molecule blockers. Small-molecule inhibitors might eventually challenge the dominance of biologics in the future. In addition to plasma membrane G protein-coupled chemokine receptors, small molecules can be designed to block intracellular enzymes that control signaling pathways. Inhibitors of tyrosine kinases expressed in lymphocytes, such as spleen tyrosine kinase and Janus kinase, are being tested in autoimmune diseases. Inactivation of the more broadly expressed mitogen-activated protein kinases could suppress inflammation driven by macrophages and mesenchymal cells. Targeting tyrosine kinases downstream of growth factor receptors might also reduce fibrosis in conditions like systemic sclerosis. The abundance of potential targets suggests that new and creative ways of evaluating safety and efficacy are needed