Expressivity Within Second-Order Transitive-Closure Logic

Second-order transitive-closure logic, SO(TC), is an expressive declarative language that captures the complexity class PSPACE. Already its monadic fragment, MSO(TC), allows the expression of various NP-hard and even PSPACE-hard problems in a natural and elegant manner. As SO(TC) offers an attractive framework for expressing properties in terms of declaratively specified computations, it is interesting to understand the expressivity of different features of the language. This paper focuses on the fragment MSO(TC), as well on the purely existential fragment SO(2TC)(exists); in 2TC, the TC operator binds only tuples of relation variables. We establish that, with respect to expressive power, SO(2TC)(exists) collapses to existential first-order logic. In addition we study the relationship of MSO(TC) to an extension of MSO(TC) with counting features (CMSO(TC)) as well as to order-invariant MSO. We show that the expressive powers of CMSO(TC) and MSO(TC) coincide. Moreover we establish that, over unary vocabularies, MSO(TC) strictly subsumes order-invariant MSO

Counting in Team Semantics

We explore several counting constructs for logics with team semantics. Counting is an important task in numerous applications, but with a somewhat delicate relationship to logic. Team semantics on the other side is the mathematical basis of modern logics of dependence and independence, in which formulae are evaluated not for a single assignment of values to variables, but for a set of such assignments. It is therefore interesting to ask what kind of counting constructs are adequate in this context, and how such constructs influence the expressive power, and the model-theoretic and algorithmic properties of logics with team semantics. Due to the second-order features of team semantics there is a rich variety of potential counting constructs. Here we study variations of two main ideas: forking atoms and counting quantifiers. Forking counts how many different values for a tuple w occur in assignments with coinciding values for v. We call this the forking degree of bar v with respect to bar w. Forking is powerful enough to capture many of the previously studied atomic dependency properties. In particular we exhibit logics with forking atoms that have, respectively, precisely the power of dependence logic and independence logic. Our second approach uses counting quantifiers E^{geq mu} of a similar kind as used in logics with Tarski semantics. The difference is that these quantifiers are now applied to teams of assignments that may give different values to mu. We show that, on finite structures, there is an intimate connection between inclusion logic with counting quantifiers and FPC, fixed-point logic with counting, which is a logic of fundamental importance for descriptive complexity theory. For sentences, the two logics have the same expressive power. Our analysis is based on a new variant of model-checking games, called threshold safety games, on a trap condition for such games, and on game interpretations

Tools and Algorithms for the Construction and Analysis of Systems

This open access two-volume set constitutes the proceedings of the 26th International Conference on Tools and Algorithms for the Construction and Analysis of Systems, TACAS 2020, which took place in Dublin, Ireland, in April 2020, and was held as Part of the European Joint Conferences on Theory and Practice of Software, ETAPS 2020. The total of 60 regular papers presented in these volumes was carefully reviewed and selected from 155 submissions. The papers are organized in topical sections as follows: Part I: Program verification; SAT and SMT; Timed and Dynamical Systems; Verifying Concurrent Systems; Probabilistic Systems; Model Checking and Reachability; and Timed and Probabilistic Systems. Part II: Bisimulation; Verification and Efficiency; Logic and Proof; Tools and Case Studies; Games and Automata; and SV-COMP 2020

Utilizing advanced modelling approaches for forecasting air travel demand: a case study of Australia’s domestic low cost carriers

One of the most pervasive trends in the global airline industry over the past few three decades has been the rapid development of low cost carriers (LCCs). Australia has not been immune to this trend. Following deregulation of Australia’s domestic air travel market in the 1990s, a number of LCCs have entered the market, and these carriers have now captured around 31 per cent of the market. Australia’s LCCs require reliable and accurate passenger demand forecasts as part of their fleet, network, and commercial planning and for scaling investments in fleet and their associated infrastructure. Historically, the multiple linear regression (MLR) approach has been the most popular and recommended method for forecasting airline passenger demand. In more recent times, however, new advanced artificial intelligence-based forecasting approaches – artificial neural networks (ANNs), genetic algorithm (GA), and adaptive neuro-fuzzy inference system (ANFIS) - have been applied in a broad range of disciplines. In light of the critical importance of passenger demand forecasts for airline management, as well as the recent developments in artificial intelligence-based forecasting methods, the key aim of this thesis was to specify and empirically examine three artificial intelligence-based approaches (ANNs, GA and ANFIS) as well as the MLR approach, in order to identify the optimum model for forecasting Australia’s domestic LCCs demand. This is the first time that such models – enplaned passengers (PAX) and revenue passenger kilometres performed (RPKs) – have been proposed and tested for forecasting Australia’s domestic LCCs demand. The results show that of the four modeling approaches used in this study that the new, and novel, ANFIS approach provides the most accurate, reliable, and highest predictive capability for forecasting Australia’s LCCs demand. A second aim of the thesis was to explore the principal determinants of Australia’s domestic LCCs demand in order to achieve a greater understanding of the factors which influence air travel demand. The results show that the primary determinants of Australia’s domestic LCCs demand are real best discount airfare, population, real GDP, real GDP per capita, unemployment, world jet fuel prices, real interest rates, and tourism attractiveness. Interestingly three determinants, unemployment, tourism attractiveness, and real interest rates, which have not been empirically examined in any previously reported study of Australia’s domestic LCCs demand, proved to be important predictor variables of Australia’s domestic LCCs demand. The thesis also found that Australia’s LCCs have increasingly embraced a hybrid business model over the past decade. This strategy is similar to LCCs based in other parts of the world. The core outcome of this research, the fact that modelling based on artificial intelligence approaches is far more effective than the traditional models prescribed by the International Civil Aviation Organization (ICAO), means that future work is essential to validate this. From an academic perspective, the modelling presented in this study offers considerable promise for future air travel demand forecasting. The results of this thesis provide new insights into LCCs passenger demand forecasting methods and can assist LCCs executives, airports, aviation consultants, and government agencies with a variety of future planning considerations

La thermorégulation comme cible thérapeutique pour la maladie d'Alzheimer

Tableau d'honneur de la FÉSPLa maladie d’Alzheimer (MA) est une maladie neurodégénérative qui se manifeste par l’apparition progressive de troubles de la mémoire. Le nombre de personnes affectées par la maladie est en constante hausse, mais il n’existe pour l’instant aucun traitement curatif pour la MA. L’âge avancé est le principal facteur de risque de la MA et est associé à un déficit de thermorégulation. De précédentes études animales montrent d’ailleurs que l’hypothermie augmente la phosphorylation de la protéine tau, l’un des principaux marqueurs neuropathologiques de la MA. La souris triple transgénique (3xTg-AD), un modèle murin de la MA, présente un déficit de thermorégulation qui s’installe progressivement avec le vieillissement et l’apparition de la neuropathologie. Une exposition aigüe au froid aggrave l’hyperphosphorylation de tau dans le cerveau de ces souris, tandis que les placer à une température thermoneutre (28°C) diminue leurs déficits de mémoire et leur pathologie amyloïde. Le tissu adipeux brun (TAB) est le principal siège de la thermogenèse chez les mammifères. La stimulation de son activité, par des expositions au froid ou l’administration d’agonistesdes récepteurs β3 adrénergiques(Rβ3A), permet de diminuer les altérations métaboliques périphériques. Puisque les maladies métaboliques sont des facteurs de risques importants pour la MA, et qu’un déficit de thermorégulation semble aggraver la MA, nous avons émis l’hypothèse que la stimulation du TAB pourrait être bénéfique pour la MA en corrigeant les déficits de thermorégulation et les troubles métaboliques. L’objectif de cette thèse était de déterminer si la stimulation de la thermogenèse du TAB permettait de diminuer la neuropathologie et les déficits comportementaux dans un modèle murin de la MA, la souris 3xTg-AD. Dans un premier temps, nous avons montré que l’âge avancé potentialisaitla phosphorylation de tau induite par une exposition aigüe au froid. Dans un second temps, nous avons montré que de courtes expositions répétées au froid permettaient d’augmenter la capacité de thermogenèse du TAB et de réduire l’intolérance au glucose des souris 3xTg-AD âgées. Une meilleure thermorégulation conférait une protection contre la phosphorylation de tau induite par une exposition aigüe au froid. De plus, nous avons observé une corrélation négative entre les niveaux du facteur de croissance des fibroblastes 21 (FGF21) et la phosphorylation de tau dans l’hippocampe, suggérant que cette hormone produite par le TAB est impliquée dans la neuroprotection contre une exposition aigüe au froid. Finalement, nous avons investigué l’effet d’un agoniste des Rβ3A sur la neuropathologie et la mémoire des souris 3xTg-AD âgées. Cette approche pharmacologique a permis d’améliorer la tolérance au glucose et d’augmenter la thermogenèse du TAB des souris 3xTg-AD et NonTg âgées de 16 mois. Le traitement a renversé le déficitde mémoire de reconnaissance et a diminué le ratiode peptides Aβ42/Aβ40 insolubles dans l’hippocampedes souris transgéniques, sans moduler la phosphorylation de la protéinetau. Ces résultats montrent que les interventions visant à stimuler la thermogenèse permettent de diminuer les désordres métaboliques et d’altérer la neuropathologie et les déficits comportementaux de la MA dans un modèle murin. Ainsi, nos résultats mettent en lumière la thermorégulation comme une nouvelle cible thérapeutique et ouvrent la voie à de nouvelles stratégies pour cette maladie.Alzheimer's disease (AD) is a neurodegenerative disease characterized by a progressive loss of memory. The number of people affected by the disease is constantly in creasing, but there is currently no curefor AD. Aging, the main risk factor for AD, is also associated with a thermoregulatory deficit. Previous animal studies have shown that hypothermia in creases the phosphorylation of the protein tau, one of the main neuropathological markers of AD. The transgenic triple mouse (3xTg-AD), a mouse model of AD neuropathology, develops thermoregulatory deficits along with the progression of the neuropathology. Acute cold exposure exacerbates tau hyperphosphorylation in the brain of 3xTg-AD mice, while exposing them to a thermoneutral environment (28°C) alleviates their memory deficits and amyloid pathology. Brown adipose tissue (BAT) is the main site of thermogenesisin mammals. The stimulation of its activity, by cold exposures or the administration of β3 adrenergic receptor agonists (β3AR), has been shown to improve peripheral metabolic determinants. Since metabolic diseases are important risk factors for AD, and thermoregulatory deficits mayworsen AD, we hypothesized that BAT stimulation could be beneficial in AD by correcting both thermoregulatory deficits and metabolic disorders. The aim of this thesis was to determine whether the stimulation of BAT thermogenesis reduces neuropathology and behavioral deficits in a mouse model of AD, the 3xTg-AD mouse. First, we showed that advanced age potentiates tau phosphorylation induced by acute cold exposure. Secondly, we observedthat repeated short cold exposures increased the thermogenesis capacity of BAT and reduced glucose intolerance in aged 3xTg-AD mice. Better thermoregulation provided protection against tau phosphorylation induced by an acute cold exposure. In addition, we reported a negative correlation between fibroblast growth factor 21 (FGF21) levels and tau phosphorylation in the hippocampus, suggesting that this BAT-secreted hormone is involved in neuroprotection against acute cold exposure. Finally, we investigated the effect of a β3AR agonist on the neuropathology and memory of old 3xTg-AD mice. This pharmacological approach improved glucose tolerance and increased BAT thermogenes is in 16-month-old 3xTg-AD and NonTg mice. The treatment reversed the recognition memory deficiency and decreased the ratio of insoluble Aβ42/Aβ40 peptides in the hippocampus of transgenic mice, without modulating tauphosphorylation. These results show that interventions aiming at stimulating thermogenes is can reduce metabolic disorders and modulate neuropathology and behavioral deficits of AD in a mousemodel. Thus, our results high light thermoregulation as a novel therapeutic target for this disease

Miten meistä tuli filosofian tohtoreita

HUOM! Pdf ei näy oikein Firefox-selaimen sisäistä pluginia käytettäessä. Avaa se erillisellä pdf-lukuohjelmalla.Tämä teos sisältää 89 pienoiselämäkertaa, jossa filosofi­sista kysymyksistä väitelleet suomalaiset kertovat koke­muksistaan matkalla kohti väitöstä. Väittelyiden aikaväli sijoittuu vuosille 1953—2010, ja mukana on monenlaisia tarinoita ja anekdootteja akateemisesta opintiestä ympäri maailmaa, Tasmaniasta Jyväskylään. Kertojina toimivat monet arvostetuimmat suomalaiset filosofit ja toisaalta vasta äskettäin tutkimustaan puolustaneet tulevaisuuden lupaukset. Kirjoittajat kertovat syttymisestään filosofiaan, opiskelu­vuosistaan, tutkijanuransa huipuista ja aallonpohjista sekä väitöstapahtumasta ja sen jälkeisistä tuntemuksista. Kertomuksia leimaa vahva henkilökohtainen sävy ja jokainen kertomus on erilainen selviytymistarina korkeim­man opinarvon saavuttamisesta ja filosofisten ongelmien määrätietoisesta pohdinnasta