Terminological cycles and the ropositional μ-calculus

We investigate terminological cycles in the terminological standard logic mathcal{ALC} with the only restriction that recursively defined concepts must occur in their definition positively. This restriction, called syntactic monotonicity, ensures the existence of least and greatest fixpoint models. It turns out that as far as syntactically monotone terminologies of mathcal{ALC} are concerned, the descriptive semantics as well as the least and greatest fixpoint semantics do not differ in the computational complexity of the corresponding subsumption relation. In fact, we prove that in each case subsumption is complete for deterministic exponential time. We then show that the expressive power of finite sets of syntactically monotone terminologies of mathcal{ALC} is the very same for the least and the greatest fixpoint semantics and, moreover, in both cases they are strictly stronger in expressive power than mathcal{ALC} augmented by regular role expressions. These results are obtained by a direct correspondence to the so-called propositional mu-calculus which allows to express least and greatest fixpoints explicitly. We propose ALC augmented by the fixpoint operators of the mu-calculus as a unifying framework for all three kinds of semantics

Organic Knowledge Network Arable - D.3.1 State-of-the-art research results and best practices

In this deliverable of the Project OK-Net Arable project, the findings from peer-review research on the productivity of organic arable crops are reported. Then the conclusions and recommendations for five most important levers which can be used by the farmers are presented. Finally, the most important recommendations of the EIP-AGRI Focus Group on Organic Farming - Optimizing Arable Yields are summarized in order to put innovation on organic farms in its social context

Long term outcome of adolescent and adult patients with pineal parenchymal tumors treated with fractionated radiotherapy between 1982 and 2003 -- a single institution's experience

Background: To evaluate the effectivity of fractionated radiotherapy in adolescent and adult patients with pineal parenchymal tumors (PPT). Methods: Between 1982 and 2003, 14 patients with PPTs were treated with fractionated radiotherapy. 4 patients had a pineocytoma (PC), one a PPT with intermediate differentiation (PPTID) and 9 patients a pineoblastoma (PB), 2 of which were recurrences. All patients underwent radiotherapy to the primary tumor site with a median total dose of 54 Gy. In 9 patients with primary PB treatment included whole brain irradiation (3 patients) or irradiation of the craniospinal axis (6 patients) with a median total dose of 35 Gy. Results: Median follow-up was 123 months in the PC patients and 109 months in the patients with primary PB. 7 patients were free from relapse at the end of follow-up. One PC patient died from spinal seeding. Among 5 PB patients treated with radiotherapy without chemotherapy, 3 developed local or spinal tumor recurrence. Both patients treated for PB recurrences died. The patient with PPTID is free of disease 7 years after radiotherapy. Conclusion: Local radiotherapy seems to be effective in patients with PC and some PPTIDs. Diagnosis and treatment of patients with more aggressive variants of PPTIDs as well as treatment of PB need to be further improved, since local and spinal failure even despite craniospinal irradiation (CSI) is common. As PPT are very rare tumors, treatment within multi-institutional trials remains necessary

Nicotinic acid adenine dinucleotide phosphate-mediated calcium signalling in effector T cells regulates autoimmunity of the central nervous system

Nicotinic acid adenine dinucleotide phosphate represents a newly identified second messenger in T cells involved in antigen receptor-mediated calcium signalling. Its function in vivo is, however, unknown due to the lack of biocompatible inhibitors. Using a recently developed inhibitor, we explored the role of nicotinic acid adenine dinucleotide phosphate in autoreactive effector T cells during experimental autoimmune encephalomyelitis, the animal model for multiple sclerosis. We provide in vitro and in vivo evidence that calcium signalling controlled by nicotinic acid adenine dinucleotide phosphate is relevant for the pathogenic potential of autoimmune effector T cells. Live two photon imaging and molecular analyses revealed that nicotinic acid adenine dinucleotide phosphate signalling regulates T cell motility and re-activation upon arrival in the nervous tissues. Treatment with the nicotinic acid adenine dinucleotide phosphate inhibitor significantly reduced both the number of stable arrests of effector T cells and their invasive capacity. The levels of pro-inflammatory cytokines interferon-gamma and interleukin-17 were strongly diminished. Consecutively, the clinical symptoms of experimental autoimmune encephalomyelitis were ameliorated. In vitro, antigen-triggered T cell proliferation and cytokine production were evenly suppressed. These inhibitory effects were reversible: after wash-out of the nicotinic acid adenine dinucleotide phosphate antagonist, the effector T cells fully regained their functions. The nicotinic acid derivative BZ194 induced this transient state of non-responsiveness specifically in post-activated effector T cells. Naïve and long-lived memory T cells, which express lower levels of the putative nicotinic acid adenine dinucleotide phosphate receptor, type 1 ryanodine receptor, were not targeted. T cell priming and recall responses in vivo were not reduced. These data indicate that the nicotinic acid adenine dinucleotide phosphate/calcium signalling pathway is essential for the recruitment and the activation of autoaggressive effector T cells within their target organ. Interference with this signalling pathway suppresses the formation of autoimmune inflammatory lesions and thus might qualify as a novel strategy for the treatment of T cell mediated autoimmune diseases

Severe neurological outcomes after very early bilateral nephrectomies in patients with autosomal recessive polycystic kidney disease (ARPKD)

To test the association between bilateral nephrectomies in patients with autosomal recessive polycystic kidney disease (ARPKD) and long-term clinical outcome and to identify risk factors for severe outcomes, a dataset comprising 504 patients from the international registry study ARegPKD was analyzed for characteristics and complications of patients with very early (� 3 months; VEBNE) and early (4�15 months; EBNE) bilateral nephrectomies. Patients with very early dialysis (VED, onset � 3 months) without bilateral nephrectomies and patients with total kidney volumes (TKV) comparable to VEBNE infants served as additional control groups. We identified 19 children with VEBNE, 9 with EBNE, 12 with VED and 11 in the TKV control group. VEBNE patients suffered more frequently from severe neurological complications in comparison to all control patients. Very early bilateral nephrectomies and documentation of severe hypotensive episodes were independent risk factors for severe neurological complications. Bilateral nephrectomies within the first 3 months of life are associated with a risk of severe neurological complications later in life. Our data support a very cautious indication of very early bilateral nephrectomies in ARPKD, especially in patients with residual kidney function, and emphasize the importance of avoiding severe hypotensive episodes in this at-risk cohort. © 2020, The Author(s)

Querying knowledge and data bases by a universal description logic with recursion

The main motivation of my work was to bring together three fields of Computer Science which are only apparently unrelated: Knowledge Representation, propositional logics of programs, and relational databases. Knowledge Representation as an important subfield of artificial intelligence, however, was definitely the focus of my attention: I did not consider the remaining two fields in their own right, but rather studied them from a Knowledge Representation point of view.Die vorliegende Arbeit beschäftigt sich damit, die Ausdrucksfähigkeit von Beschreibungslogiken so zu erhöhen, dass diese für praktische Zwecke einsetzbar werden. Gleichzeitig soll jedoch die Berechnungskomplexität, die selbst ausdrucksschwachen Beschreibungslogiken inhärent ist, vermieden werden

Querying knowledge and data bases by a universal description logic with recursion

The main motivation of my work was to bring together three fields of Computer Science which are only apparently unrelated: Knowledge Representation, propositional logics of programs, and relational databases. Knowledge Representation as an important subfield of artificial intelligence, however, was definitely the focus of my attention: I did not consider the remaining two fields in their own right, but rather studied them from a Knowledge Representation point of view.Die vorliegende Arbeit beschäftigt sich damit, die Ausdrucksfähigkeit von Beschreibungslogiken so zu erhöhen, dass diese für praktische Zwecke einsetzbar werden. Gleichzeitig soll jedoch die Berechnungskomplexität, die selbst ausdrucksschwachen Beschreibungslogiken inhärent ist, vermieden werden

Tractable reasoning in a universal description logic

Klaus Schild German Research Center for Artificial Intelligence Stuhlsatzenhausweg 3, D-66123 Saarbrucken, FRG e-mail: [email protected] 1 Introduction Description logics (also called terminological logics or concept languages) have been designed for the logical reconstruction and specification of knowledge representation systems descending from Kl-One such as Back, Classic, KRIS, and Loom. 1 These systems are used to make the terminology of an application domain explicit and then to classify these definitions automatically into a taxonomy according to semantic relations like subsumption and equivalence. More precisely, automatic classification refers to the ability to insert a new concept into the taxonomy in such a way that it is directly linked to the most specific concept it is subsumed by and to the most general concept it in turn subsumes. Terminological knowledge representation systems thereby support the task to formalize an application in at least two respects. On the..