A game theoretical approach to the algebraic counterpart of the Wagner hierarchy

La hiérarchie de Wagner constitue à ce jour la plus fine classification des langages ω-réguliers. Par ailleurs, l'approche algébrique de la théorie de langages formels montre que ces ensembles ω-réguliers correspondent précisément aux langages reconnaissables par des ω-semigroupes finis pointés. Ce travail s'inscrit dans ce contexte en fournissant une description complète de la contrepartie algébrique de la hiérarchie de Wagner, et ce par le biais de la théorie descriptive des jeux de Wadge. Plus précisément, nous montrons d'abord que le degré de Wagner d'un langage ω-régulier est effectivement un invariant syntaxique. Nous définissons ensuite une relation de réduction entre ω-semigroupes pointés par le biais d'un jeu infini de type Wadge. La collection de ces structures algébriques ordonnée par cette relation apparaît alors comme étant isomorphe à la hiérarchie de Wagner, soit un quasi bon ordre décidable de largeur 2 et de hauteur ω. Nous exposons par la suite une procédure de décidabilité de cette hiérarchie algébrique : on décrit une représentation graphique des ω-semigroupes finis pointés, puis un algorithme sur ces structures graphiques qui calcule le degré de Wagner de n'importe quel élément. Ainsi le degré de Wagner de tout langage ω-régulier peut être calculé de manière effective directement sur son image syntaxique. Nous montrons ensuite comment construire directement et inductivement une structure de n''importe quel degré. Nous terminons par une description détaillée des invariants algébriques qui caractérisent tous les degrés de cette hiérarchie. Abstract The Wagner hierarchy is known so far to be the most refined topological classification of ω-rational languages. Also, the algebraic study of formal languages shows that these ω-rational sets correspond precisely to the languages recognizable by finite pointed ω-semigroups. Within this framework, we provide a construction of the algebraic counterpart of the Wagner hierarchy. We adopt a hierarchical game approach, by translating the Wadge theory from the ω-rational language to the ω-semigroup context. More precisely, we first show that the Wagner degree is indeed a syntactic invariant. We then define a reduction relation on finite pointed ω-semigroups by means of a Wadge-like infinite two-player game. The collection of these algebraic structures ordered by this reduction is then proven to be isomorphic to the Wagner hierarchy, namely a well-founded and decidable partial ordering of width 2 and height $\omega^\omega$. We also describe a decidability procedure of this hierarchy: we introduce a graph representation of finite pointed ω-semigroups allowing to compute their precise Wagner degrees. The Wagner degree of every ω-rational language can therefore be computed directly on its syntactic image. We then show how to build a finite pointed ω-semigroup of any given Wagner degree. We finally describe the algebraic invariants characterizing every Wagner degree of this hierarchy.

Localization and fine structure of a vaccinia virus gene encoding an envelope antigen.

The major antigen on the envelope of extracellular vaccinia virus particles is a polypeptide with an apparent molecular weight of 37,000 (p37K; G. Hiller and K. Weber, J. Virol. 55:651-659, 1985). The gene encoding p37K was mapped in the vaccinia virus genome by hybrid selection of RNA followed by in vitro translation. p37K was then identified among the in vitro translation products by immunoprecipitation with a monoclonal antibody. The gene is located close to the right-hand end of the HindIII F fragment. The corresponding region of the DNA was sequenced, and an open reading frame encoding a polypeptide of 41,748 daltons was observed. The 5' end of the mRNA, as defined by nuclease S1 analysis, maps within only a few nucleotides of the translation initiation codon. Examination of the DNA sequence around the putative initiation site of transcription revealed a characteristic sequence, TAAATG, which includes the ATG translation initiation codon and which is conserved in all but one late gene so far analyzed. It is therefore likely that this sequence is an important regulatory signal for late gene expression in vaccinia virus.

Mutations in NDUFB11, Encoding a Complex I Component of the Mitochondrial Respiratory Chain, Cause Microphthalmia with Linear Skin Defects Syndrome.

Microphthalmia with linear skin defects (MLS) syndrome is an X-linked male-lethal disorder also known as MIDAS (microphthalmia, dermal aplasia, and sclerocornea). Additional clinical features include neurological and cardiac abnormalities. MLS syndrome is genetically heterogeneous given that heterozygous mutations in HCCS or COX7B have been identified in MLS-affected females. Both genes encode proteins involved in the structure and function of complexes III and IV, which form the terminal segment of the mitochondrial respiratory chain (MRC). However, not all individuals with MLS syndrome carry a mutation in either HCCS or COX7B. The majority of MLS-affected females have severe skewing of X chromosome inactivation, suggesting that mutations in HCCS, COX7B, and other as-yet-unidentified X-linked gene(s) cause selective loss of cells in which the mutated X chromosome is active. By applying whole-exome sequencing and filtering for X-chromosomal variants, we identified a de novo nonsense mutation in NDUFB11 (Xp11.23) in one female individual and a heterozygous 1-bp deletion in a second individual, her asymptomatic mother, and an affected aborted fetus of the subject's mother. NDUFB11 encodes one of 30 poorly characterized supernumerary subunits of NADH:ubiquinone oxidoreductase, known as complex I (cI), the first and largest enzyme of the MRC. By shRNA-mediated NDUFB11 knockdown in HeLa cells, we demonstrate that NDUFB11 is essential for cI assembly and activity as well as cell growth and survival. These results demonstrate that X-linked genetic defects leading to the complete inactivation of complex I, III, or IV underlie MLS syndrome. Our data reveal an unexpected role of cI dysfunction in a developmental phenotype, further underscoring the existence of a group of mitochondrial diseases associated with neurocutaneous manifestations.

A model for the evolution of reinforcement learning in fluctuating games

Many species are able to learn to associate behaviours with rewards as this gives fitness advantages in changing environments. Social interactions between population members may, however, require more cognitive abilities than simple trial-and-error learning, in particular the capacity to make accurate hypotheses about the material payoff consequences of alternative action combinations. It is unclear in this context whether natural selection necessarily favours individuals to use information about payoffs associated with nontried actions (hypothetical payoffs), as opposed to simple reinforcement of realized payoff. Here, we develop an evolutionary model in which individuals are genetically determined to use either trial-and-error learning or learning based on hypothetical reinforcements, and ask what is the evolutionarily stable learning rule under pairwise symmetric two-action stochastic repeated games played over the individual's lifetime. We analyse through stochastic approximation theory and simulations the learning dynamics on the behavioural timescale, and derive conditions where trial-and-error learning outcompetes hypothetical reinforcement learning on the evolutionary timescale. This occurs in particular under repeated cooperative interactions with the same partner. By contrast, we find that hypothetical reinforcement learners tend to be favoured under random interactions, but stable polymorphisms can also obtain where trial-and-error learners are maintained at a low frequency. We conclude that specific game structures can select for trial-and-error learning even in the absence of costs of cognition, which illustrates that cost-free increased cognition can be counterselected under social interactions.

A geometric chracterization of the nucleolus of the assignment game

Maschler et al. (1979) caracteritzen geomètricament la intersecció del kernel i del core en els jocs cooperatius, demostrant que les distribucions que pertanyen a ambdós conjunts es troben en el punt mig d’un cert rang de negociació entre parelles de jugadors. En el cas dels jocs d’assignació, aquesta caracterització vol dir que el kernel només conté aquells elements del core on el màxim que un jugador pot transferir a una parella òptima és igual al màxim que aquesta parella li pot transferir, sense sortir-se’n del core. En aquest treball demostrem que el nucleolus d’un joc d’assignació queda caracteritzat si requerim que aquesta propietat de bisecció es compleixi no només per parelles, sinó també per coalicions entre sectors aparellades òptimament.

A geometric chracterization of the nucleolus of the assignment game

Maschler et al. (1979) caracteritzen geomètricament la intersecció del kernel i del core en els jocs cooperatius, demostrant que les distribucions que pertanyen a ambdós conjunts es troben en el punt mig d’un cert rang de negociació entre parelles de jugadors. En el cas dels jocs d’assignació, aquesta caracterització vol dir que el kernel només conté aquells elements del core on el màxim que un jugador pot transferir a una parella òptima és igual al màxim que aquesta parella li pot transferir, sense sortir-se’n del core. En aquest treball demostrem que el nucleolus d’un joc d’assignació queda caracteritzat si requerim que aquesta propietat de bisecció es compleixi no només per parelles, sinó també per coalicions entre sectors aparellades òptimament.

A Learner-Centred Game-Design Approach: Impacts on teachers" creativity

This study presents an innovative pedagogical approach where teachers become game designers and engage in creative teaching practices. Within co-design training workshops, 21 Spanish primary and secondary school teachers have developed their own Game-Based Learning (GBL) scenarios, especially tailored to their teaching contexts and students profiles. In total, teachers developed 13 GBL scenarios and put them into practice in real teaching contexts. The present paper analyses the impacts of this learner-centred game design approach on teachers" creativity from three different points of view: the GBL design process, the GBL scenario, and the teaching processes at stake.

Creating CRM Concept for Internet Gaming Business - Case: European Game & Entertainment Technology

Työn tavoitteena oli luoda asiakassuhteidenhallintakonsepti Internetpelijärjestelmälle sekä luoda asiakassuhteidenhallintaprosessi keskittyen viestintä- ja personointiominaisuuksiin. Lisäksi työssä määritettiin CRM järjestelmän ominaisuudet ja toiminnallisuudet. Työ toteutettiin kvalitatiivisena case tutkimuksena. Tiedot empiiristä tutkimusta varten kerättiin haastattelemalla kohderyhminä olleita asiakkaita sekä case-yrityksen avainhenkilöitä. Työssä selvitettiin ensin suhdemarkkinoinnin perusteet, konsepti sekä asiakassuhteen arvo. Yhteys peliliiketoimintaan sekä Internet peliliiketoiminnan perusteet esitettin. CRM konsepti määriteltiin teoriassa sekä CRM prosessi määritettin perustuen teoreettiseen tutkimukseen sekä empiirisiin tuloksiin. Seuraavaksi luotiin CRM konsepti case-yritykselle perustuen CRM prosessin tuottamaan informaatioon ja asiakastarpeisiin. Asiakassuhteiden hallinta voidaan jakaa kolmeen tasoon - strategiseen, analyyttiseen ja toiminnalliseen. CRM konseptin luominen on tapauskohtainen prosessi. Siihen vaikuttaa voimakkaasti toimiala, millä yritys toimii. Myös asiakastarpeiden kartoituksella on tärkeä merkitys onnistuneen konseptin luomisessa. Sekä kirjallisuuteen perustuvat, että empiiriset havainnot painottivat personoinnin ja viestinnän vaikutusta CRM konseptissa.

O game CityVille: uma nova tendência da Web

O objetivo principal desse artigo é analisar o jogo social CityVille criado pela empresa Zynga, uma das últimas tendências do Facebook encontrado e disponível na web. A escolha do corpus game CityVille deve-se ao interesse de buscar compreender o por que esse jogo obteve tamanho sucesso e seja atualmente um dos jogos sociais/digitais de maior destaque e adeptos da rede social Facebook. Busca-se dessa maneira depreender de que maneira os jogos sociais tem evoluído e transformado as relações comunicacionais entre os usuários da rede. As redes sociais têm se tornando cada vez mais importantes e estão vinculadas a vida das pessoas. Com o desenvolvimento da linguagem digital, a forma com que as pessoas passaram a interagir se transforma, pois essas se comunicam através do computador em tempo real. O estudo busca fazer uma análise plural do jogo CityVille destacando distintos pontos de vista do jogo social. Propomos verificar as relações entre: o uso e os usuários, e a tecnologia e o conteúdo do jogo. Nas conclusões explicitaremos quais serão as direções possíveis do futuro dos jogos sociais da web.

Prevalence of Acute Coronary Syndrome in Patients Suspected for Pulmonary Embolism or Acute Aortic Syndrome: Rationale for the Triple Rule-out Concept.

BACKGROUND: The aims of the study were to evaluate the prevalence of acute coronary syndrome (ACS) among patients presenting with atypical chest pain who are evaluated for acute aortic syndrome (AAS) or pulmonary embolism (PE) with computed tomoangiography (CTA) and discuss the rationale for the use of triple rule-out (TRO) protocol for triaging these patients. METHODS: This study is a retrospective analysis of patients presenting with atypical chest pain and evaluated with thoracic (CTA), for suspicion of AAS/PE. Two physicians reviewed patient files for demographic characteristics, initial CT and final clinical diagnosis. Patients were classified according to CTA finding into AAS, PE and other diagnoses and according to final clinical diagnosis into AAS, PE, ACS and other diagnoses. RESULTS: Four hundred and sixty-seven patients were evaluated: 396 (84.8%) patients for clinical suspicion of PE and 71 (15.2%) patients for suspicion of AAS. The prevalence of ACS and AAS was low among the PE patients: 5.5% and 0.5% respectively (P = 0.0001), while the prevalence of ACS and PE was 18.3% and 5.6% among AAS patients (P = 0.14 and P = 0.34 respectively). CONCLUSION: The prevalence of ACS and AAS among patients suspected clinically of having PE is limited while the prevalence of ACS and PE among patients suspected clinically of having AAS is significant. Accordingly patients suspected for PE could be evaluated with dedicated PE CTA while those suspected for AAS should still be triaged using TRO protocol.

How institutions shaped the last major evolutionary transition to large-scale human societies.

What drove the transition from small-scale human societies centred on kinship and personal exchange, to large-scale societies comprising cooperation and division of labour among untold numbers of unrelated individuals? We propose that the unique human capacity to negotiate institutional rules that coordinate social actions was a key driver of this transition. By creating institutions, humans have been able to move from the default 'Hobbesian' rules of the 'game of life', determined by physical/environmental constraints, into self-created rules of social organization where cooperation can be individually advantageous even in large groups of unrelated individuals. Examples include rules of food sharing in hunter-gatherers, rules for the usage of irrigation systems in agriculturalists, property rights and systems for sharing reputation between mediaeval traders. Successful institutions create rules of interaction that are self-enforcing, providing direct benefits both to individuals that follow them, and to individuals that sanction rule breakers. Forming institutions requires shared intentionality, language and other cognitive abilities largely absent in other primates. We explain how cooperative breeding likely selected for these abilities early in the Homo lineage. This allowed anatomically modern humans to create institutions that transformed the self-reliance of our primate ancestors into the division of labour of large-scale human social organization.

PERC rule to exclude the diagnosis of pulmonary embolism in emergency low-risk patients: study protocol for the PROPER randomized controlled study.

BACKGROUND: The diagnosis of Pulmonary Embolism (PE) in the emergency department (ED) is crucial. As emergency physicians fear missing this potential life-threatening condition, PE tends to be over-investigated, exposing patients to unnecessary risks and uncertain benefit in terms of outcome. The Pulmonary Embolism Rule-out Criteria (PERC) is an eight-item block of clinical criteria that can identify patients who can safely be discharged from the ED without further investigation for PE. The endorsement of this rule could markedly reduce the number of irradiative imaging studies, ED length of stay, and rate of adverse events resulting from both diagnostic and therapeutic interventions. Several retrospective and prospective studies have shown the safety and benefits of the PERC rule for PE diagnosis in low-risk patients, but the validity of this rule is still controversial. We hypothesize that in European patients with a low gestalt clinical probability and who are PERC-negative, PE can be safely ruled out and the patient discharged without further testing. METHODS/DESIGN: This is a controlled, cluster randomized trial, in 15 centers in France. Each center will be randomized for the sequence of intervention periods: a 6-month intervention period (PERC-based strategy) followed by a 6-month control period (usual care), or in reverse order, with 2 months of "wash-out" between the 2 periods. Adult patients presenting to the ED with a suspicion of PE and a low pre test probability estimated by clinical gestalt will be eligible. The primary outcome is the percentage of failure resulting from the diagnostic strategy, defined as diagnosed venous thromboembolic events at 3-month follow-up, among patients for whom PE has been initially ruled out. DISCUSSION: The PERC rule has the potential to decrease the number of irradiative imaging studies in the ED, and is reported to be safe. However, no randomized study has ever validated the safety of PERC. Furthermore, some studies have challenged the safety of a PERC-based strategy to rule-out PE, especially in Europe where the prevalence of PE diagnosed in the ED is high. The PROPER study should provide high-quality evidence to settle this issue. If it confirms the safety of the PERC rule, physicians will be able to reduce the number of investigations, associated subsequent adverse events, costs, and ED length of stay for patients with a low clinical probability of PE. TRIAL REGISTRATION: NCT02375919 .

Characterizing RecA-Independent Induction of Shiga toxin2-encoding Phages by EDTA Treatment

The bacteriophage life cycle has an important role in Shiga toxin (Stx) expression. The induction of Shiga toxin-encoding phages (Stx phages) increases toxin production as a result of replication of the phage genome, and phage lysis of the host cell also provides a means of Stx toxin to exit the cell. Previous studies suggested that prophage induction might also occur in the absence of SOS response, independently of RecA.