187 research outputs found
Epistemic Foundation of Stable Model Semantics
Stable model semantics has become a very popular approach for the management
of negation in logic programming. This approach relies mainly on the closed
world assumption to complete the available knowledge and its formulation has
its basis in the so-called Gelfond-Lifschitz transformation.
The primary goal of this work is to present an alternative and
epistemic-based characterization of stable model semantics, to the
Gelfond-Lifschitz transformation. In particular, we show that stable model
semantics can be defined entirely as an extension of the Kripke-Kleene
semantics. Indeed, we show that the closed world assumption can be seen as an
additional source of `falsehood' to be added cumulatively to the Kripke-Kleene
semantics. Our approach is purely algebraic and can abstract from the
particular formalism of choice as it is based on monotone operators (under the
knowledge order) over bilattices only.Comment: 41 pages. To appear in Theory and Practice of Logic Programming
(TPLP
PBT plasticity loss induced by oxidative and hydrolysis ageing
This paper reports the study of embrittlement of PBT submitted either to thermal or hydrolytic ageing. All changes were followed up by tensile tests, rheometry in molten state and gel permeation chromatography for molar mass changes, SAXS and DSC experiments for crystallinity changes. Both kind of ageing were shown to induce predominant chain scissions with moderate crystallinity increase, in great part due to annealing. The combination of all results were used to establish a Mw - χc embrittlement window helping for a determination of an end of life criterion.The authors would like to thank the ANRT for granting this project (N °2019/1467). The authors would also like to thank V. Michel, RX manager at PIMM laboratory for helping in SAXS measurements and data treatment
From fuzzy to annotated semantic web languages
The aim of this chapter is to present a detailed, selfcontained and comprehensive account of the state of the art in representing and reasoning with fuzzy knowledge in Semantic Web Languages such as triple languages RDF/RDFS, conceptual languages of the OWL 2 family and rule languages. We further show how one may generalise them to so-called annotation domains, that cover also e.g. temporal and provenance extensions
Query Answering in Normal Logic Programs under Uncertainty
We present a simple, yet general top-down query answering procedure for normal logic programs over lattices and bilattices, where functions may appear in the rule bodies. Its interest relies on the fact that many approaches to paraconsistency and uncertainty in logic programs with or without non-monotonic negation are based on bilattices or lattices, respectively
Gravitational stability and dynamical overheating of stellar disks of galaxies
We use the marginal stability condition for galactic disks and the stellar
velocity dispersion data published by different authors to place upper limits
on the disk local surface density at two radial scalelengths .
Extrapolating these estimates, we constrain the total mass of the disks and
compare these estimates to those based on the photometry and color of stellar
populations. The comparison reveals that the stellar disks of most of spiral
galaxies in our sample cannot be substantially overheated and are therefore
unlikely to have experienced a significant merging event in their history. The
same conclusion applies to some, but not all of the S0 galaxies we consider.
However, a substantial part of the early type galaxies do show the stellar
velocity dispersion well in excess of the gravitational stability threshold
suggesting a major merger event in the past. We find dynamically overheated
disks among both seemingly isolated galaxies and those forming pairs. The ratio
of the marginal stability disk mass estimate to the total galaxy mass within
four radial scalelengths remains within a range of 0.4---0.8. We see no
evidence for a noticeable running of this ratio with either the morphological
type or color index.Comment: 25 pages, 5 figures, accepted to Astronomy Letter
Cardiac-Specific Expression of the Tetracycline Transactivator Confers Increased Heart Function and Survival Following Ischemia Reperfusion Injury
Mice expressing the tetracycline transactivator (tTA) transcription factor driven by the rat α-myosin heavy chain promoter (α-MHC-tTA) are widely used to dissect the molecular mechanisms involved in cardiac development and disease. However, these α-MHC-tTA mice exhibit a gain-of-function phenotype consisting of robust protection against ischemia/reperfusion injury in both in vitro and in vivo models in the absence of associated cardiac hypertrophy or remodeling. Cardiac function, as assessed by echocardiography, did not differ between α-MHC-tTA and control animals, and there were no noticeable differences observed between the two groups in HW/TL ratio or LV end-diastolic and end-systolic dimensions. Protection against ischemia/reperfusion injury was assessed using isolated perfused hearts where α-MHC-tTA mice had robust protection against ischemia/reperfusion injury which was not blocked by pharmacological inhibition of PI3Ks with LY294002. Furthermore, α-MHC-tTA mice subjected to coronary artery ligation exhibited significantly reduced infarct size compared to control animals. Our findings reveal that α-MHC-tTA transgenic mice exhibit a gain-of-function phenotype consisting of robust protection against ischemia/reperfusion injury similar to cardiac pre- and post-conditioning effects. However, in contrast to classical pre- and post-conditioning, the α-MHC-tTA phenotype is not inhibited by the classic preconditioning inhibitor LY294002 suggesting involvement of a non-PI3K-AKT signaling pathway in this phenotype. Thus, further study of the α-MHC-tTA model may reveal novel molecular targets for therapeutic intervention during ischemic injury
SPIRAL II Project (electron option) - Preliminary Design Study
This document presents a Preliminary Design Study (PDS) of the electron option of the SPIRAL II project
Vessel co-option mediates resistance to anti-angiogenic therapy in liver metastases
The efficacy of angiogenesis inhibitors in cancer is limited by resistance mechanisms that are poorly understood. Notably, instead of through the induction of angiogenesis, tumor vascularization can occur through the nonangiogenic mechanism of vessel co-option. Here we show that vessel co-option is associated with a poor response to the anti-angiogenic agent bevacizumab in patients with colorectal cancer liver metastases. Moreover, we find that vessel co-option is also prevalent in human breast cancer liver metastases, a setting in which results with anti-angiogenic therapy have been disappointing. In preclinical mechanistic studies, we found that cancer cell motility mediated by the actin-related protein 2/3 complex (Arp2/3) is required for vessel co-option in liver metastases in vivo and that, in this setting, combined inhibition of angiogenesis and vessel co-option is more effective than the inhibition of angiogenesis alone. Vessel co-option is therefore a clinically relevant mechanism of resistance to anti-angiogenic therapy and combined inhibition of angiogenesis and vessel co-option might be a warranted therapeutic strategy
Surgical resectability of pancreatic adenocarcinoma: CTA
Imaging studies play an important role in the diagnosis and management of patients with pancreatic adenocarcinoma. Computed tomography (CT) is the most widely available and best validated modality for imaging these patients. Meticulous technique following a well-designed pancreas protocol is essential for maximizing the diagnostic efficacy of CT. After the diagnosis of pancreatic adenocarcinoma is made, the key to management is staging to determine resectability. In practice, staging often entails predicting the presence or absence of vascular invasion by tumor, for which several radiologic grading systems exist. With advances in surgical techniques, the definition of resectability is in evolution, and it is crucial that radiologists have an understanding of the implications of findings that are relevant to the determination of resectability
- …