Term Graph Representations for Cyclic Lambda-Terms

We study various representations for cyclic lambda-terms as higher-order or as first-order term graphs. We focus on the relation between `lambda-higher-order term graphs' (lambda-ho-term-graphs), which are first-order term graphs endowed with a well-behaved scope function, and their representations as `lambda-term-graphs', which are plain first-order term graphs with scope-delimiter vertices that meet certain scoping requirements. Specifically we tackle the question: Which class of first-order term graphs admits a faithful embedding of lambda-ho-term-graphs in the sense that: (i) the homomorphism-based sharing-order on lambda-ho-term-graphs is preserved and reflected, and (ii) the image of the embedding corresponds closely to a natural class (of lambda-term-graphs) that is closed under homomorphism? We systematically examine whether a number of classes of lambda-term-graphs have this property, and we find a particular class of lambda-term-graphs that satisfies this criterion. Term graphs of this class are built from application, abstraction, variable, and scope-delimiter vertices, and have the characteristic feature that the latter two kinds of vertices have back-links to the corresponding abstraction. This result puts a handle on the concept of subterm sharing for higher-order term graphs, both theoretically and algorithmically: We obtain an easily implementable method for obtaining the maximally shared form of lambda-ho-term-graphs. Also, we open up the possibility to pull back properties from first-order term graphs to lambda-ho-term-graphs. In fact we prove this for the property of the sharing-order successors of a given term graph to be a complete lattice with respect to the sharing order. This report extends the paper with the same title (http://arxiv.org/abs/1302.6338v1) in the proceedings of the workshop TERMGRAPH 2013.Comment: 35 pages. report extending proceedings article on arXiv:1302.6338 (changes with respect to version v2: added section 8, modified Proposition 2.4, added Remark 2.5, added Corollary 7.11, modified figures in the conclusion

Modèle de la diffusion pour l'amélioration de la qualité de la vidéo : débruitage et constance des couleurs

De nombreux problèmes en vision artificielle s’apparentent à la diffusion. Ils sont en général posés sous la forme d’équations aux dérivées partielles (EDP) qui expriment un problème physique et qui doivent être résolues dans l’ensemble du domaine, image ou vidéo. Une grande classe d’EDP est constituée par les processus de diffusion, assimilables à des phénomènes de transfert d’énergie dans le milieu étudié. Les méthodes classiques pour résoudre ces problèmes utilisent des processus locaux purement mathématiques, qui ne permettent pas d’approche intuitive possible. Dans ce mémoire, nous présentons une extension au domaine vidéo de travaux visant à dépasser les limitations des modèles mathématiques locaux en résolvant le problème physique global plutôt que les EDP, grâce à un modèle image basé sur la Topologie Algébrique Calculatoire (TAC). Cette approche consiste à extraire du problème modélisé les lois élémentaires qui le composent grâce à des analogies dans le domaine de la Physique. Ces lois sont décomposées en deux classes: les lois de conservation sont exprimées sans approximation grâce au support topologique du modèle, alors que les lois constitutives nécessitent des approximations qui peuvent être choisies en fonction du comportement souhaité de l’algorithme. Une méthodologie de résolution des problèmes de diffusion vidéo est présentée, ce qui amène à deux applications: le débruitage vidéo et la constance de la couleur selon le modèle retinex, pour la vidéo. Des résultats expérimentaux valident ces applications

What Are the Possible Causes for Autism Spectrum Disorder?

Ever since the mid 1980’s when Autism Spectrum Disorder (ASD) started to become increasingly prevalent, researchers have been trying to find a possible cause for it. Autism Spectrum Disorder is a developmental disorder that manifests itself in children who are between 18-30 months old. People with autism have reduced social skills, and they have a difficult time communicating verbally and non-verbally. Autism is diagnosed through a questionnaire and other instruments that allow psychologists, psychiatrists, speech therapists, neurologists and many other doctors to determine if a child has a form of ASD. There are many theories about what causes autism. It has been widely believed that vaccines, specifically the MMR vaccine causes autism, but that theory has been disproven. Another possibility is the role genetics plays in ASD. Many studies have been done to determine which genes might cause autism. Because of the heterogeneity of the symptoms and behaviors of people with autism and general genetic complexity it has been hard to find a specific genetic cause of autism. While a confirmed gene has not been determined to cause autism many studies have been done, some using whole-exome sequencing (WES) to see if mutations in parent’s genes caused their children to have autism. It is also possible that autism can be caused by hereditary or parental factors. There have also been theories that environmental factors play a role in autism such as exposure to tobacco, pollutants, and metals, and including maternal conditions that could affect the fetus. While many of the studies were inconclusive, and a confirmed cause of autism has not been found, the studies do show that genetics does play a major role in ASD, though more studies will have to be done to determine how and which genes cause it

Situaciones críticas : catástrofes naturales versus crisis económicas

Suponen un duro golpe para el país que las padece por su dificultad de predicción y sus fuertes repercusiones tanto a nivel de Estado como de población. En este sentido, ambas tienen una consecuencia en común: la reducción del bienestar. Pero, ¿cuáles son las más dificiles de superar

Learning through activity-dependent plasticity modulation

International audienc

A fonética e fonologia da harmonia de [ATR] no português brasileiro

Orientadores: Maria Bernadete Marques Abaurre, Silke HamannTese (doutorado) - Universidade Estadual de Campinas, Instituto de Estudos da Linguagem e University of AmsterdamResumo: Este trabalho apresenta uma análise das vogais pretônicas alvos de harmonia vocálica no português brasileiro. A partir da análise dos dialetos Gaúcho e Baiano, o trabalho descreve acusticamente as vogais pretônicas e tônicas envolvidas no processo de harmonia. O interesse pelo tema decorre da limitada abordagem fonético-acústica do fenômeno na literatura da área, sobretudo para investigar o papel de vogais baixas no gatilho da harmonia, assim como o papel das consoantes adjacentes. O trabalho aprofunda a observação de harmonia com vogais baixas constatada por Abaurre-Gnerre (1981), fenômeno defendido como um processo de harmonia governado pelo traço [ATR]. Para isso, desenvolveu-se um experimento que contou com a participação de seis sujeitos (3 homens e 3 mulheres) de cada dialeto. A análise fonético-acústica das vogais partiu das medidas do primeiro e segundo formantes (F1 e F2) das vogais acentuadas e das pretônicas. A partir da descrição acústica das vogais do português brasileiro, investigou-se em específico o comportamento das vogais pretônicas /e/ e /o/, alvos do processo de harmonia,constatando-se experimentalmente que a influência coarticulatória principal advém das vogais tônicas baixas /?, a, ?/ que agem como gatilho da harmonização. Partindo-se, então, dos resultados experimentais, o trabalho desenvolve uma metodologia chamada de Vowel Threshold baseada nas medidas dos parâmetros acústicos F1 e F2. Vowel Threshold tem como objetivo estimar limiares de categorias vocálicas no espaço acústico e desta forma mapear os movimentos de alçamento e abaixamento, anteriorização e posteriorização na produção de uma vogal. Esse método reduz os valores de F1 e F2 a uma escala que tem como ponto de referência o valor zero, que seria considerado o valor esperado para o token de uma vogal se não houvesse vieses introduzidos pela coarticulação V-V, pelas consoantes intervenientes ou outro processo relacionado à fala. Com essa medida, estipula-se um valor crítico que determina se uma vogal sofreu movimentos intra ou inter categoria. Os resultados da análise das medidas de Vowel Threshold evidenciaram que as vogais /e, o/ de todos os sujeitos não tendem ao alçamento para [i, u], mas são abaixadas para [?, ?] pelos falantes tanto do dialeto Gaucho quando do dialeto Baiano, embora haja variação intra e inter-falantes. Os resultados experimentais evidenciam ainda: (1) consoantes precedentes não possuem efeito de abaixamento ou de alçamento nas vogais /e, o/; (2) as consoantes soantes intervenientes são transparentes ao abaixamento nos dois dialetos, enquanto as obstruintes parecem ser opacas no dialeto Gaucho; (3) há um processo dissimilátorio no dialeto Baiano que não se configura como desarmonia, mas indica uma tendência a abaixamento intra-categoria, motivado pelo desarmonia de posterioridade entre o alvo e o gatilho. O trabalho ainda apresenta uma re-análise dos corpora de Bisol (1981) e Barbosa da Silva (1989) de modo a verificar o processo de harmonia de [+alto] constatado por essas autoras para discutir a supremacia da harmonia de altura no português brasileiro, contrastando com os resultados experimentais encontrados. Por fim, o trabalho evidencia que a harmonia de [ATR] parece ser o processo ativo do português brasileiro; e como evidência para isso, são trazidos argumentos da interação fonologia-morfologia, da contrastividade de vogais, da atribuição do acento secundário e do enviesamento introduzido pela ortografia nas análises do processo harmonia vocálica. Argumenta-se também que há um bloqueio da harmonia de [+alto] cuja motivação parece estar nas presença das oclusivas coronais /t, d/ precedentes às vogais-alvo. Traz-se evidência da literatura de que a harmonia de [+alto] é evitada por linguísticas, mas também sociolinguísticas, com resultados indicando um uso decrescente da harmonia de altura considerandos-se a idade e a escolaridade dos falantesAbstract: This study analyzes pre-stressed vowels that undergo vowel harmony in Brazilian Portuguese. Based on the analysis of the Gaucho and Baiano dialects, this work provides an acoustic description of pre-stressed and stressed vowels involved in vowel harmony. This subject is relevant because of the limited amount of acoustic-phonetic studies of this phenomenon in the literature, particularly of the role of low vowels in triggering vowel harmony, as well as the role of adjacent consonants. This study investigates the harmony patterns found by Abaurre-Gnerre (1981), a phenomenon which is hypothesized in this research as a process of harmony governed by the feature [ATR]. For this purpose, we developed a reading experiment with six participants (3 men and 3 women) from each dialect. The acoustic-phonetic analysis of the vowels was based on the measurements of the first and second formants (F1 and F2) of the pre-vowel and stressed vowels. From the acoustic description of the whole set of Brazilian Portuguese vowels, we found that the pre-stressed vowel harmony targets /e/ and /o/ are affected primarily by the low vowels /?, a, ?/, which can be considered the triggers. From the experimental results, we developed a method called Vowel Threshold, which is based on measurements of F1 and F2 to estimate thresholds of vowel categories in the acoustic space and therefore map the movements of raising, lowering, vowel-fronting and vowel-backing in vowel production. This method reduces the values of F1 and F2 to a scale that has zero as the reference point, which would be considered the expected value for the token of a vowel if there were no biases introduced by the V-to-V coarticulation, by the intervening consonants or other process related to speech. With this measurement, a critical value is stipulated to determine whether a vowel has undergone intra-category or inter-category movements. The results of the analysis of the Vowel Threshold measurements showed that the vowels /e, o/ of all subjects do not tend to be raised to [i, u], rather they are lowered to [?, ?] by speakers of both the Gaucho and Baiano dialects. Moreover, the experimental results show that: (1) the preceding consonants have no effect of lowering or raising in the vowels /e, o/; (2) the intervening sounding consonants are transparent to the lowering in the two dialects, while the obstruents appear to be opaque in the Gaucho dialect; (3) there is a dissimilatory process in Baiano that does not seem to be a disharmony, but indicates a tendency for intra-category lowering, motivated by the disagreement in [back] of the target and the trigger. The work also presents a re-analysis of the Bisol (1981) and Barbosa da Silva (1989) corpora in order to examine the process of [+high] harmony verified by those authors to discuss the supremacy of this sort of harmony in Brazilian Portuguese in contrast with the experimental results found in this work. Finally, this study shows that the BP [ATR] harmony seems to be the active harmony in Brazilian Portuguese; and as evidence for this, arguments from phonology-morphology interaction, vowel contrastiveness, secondary stress assignment, and orthography biasing in the analysis of vowel harmony are brought into the discussion. It is argued that there is a consonantal blocking effect of [+high] harmony motivated by certain preceding consonants to the target vowels. Evidence of [+high] harmony avoidance is also found in the sociolinguistic literature that shows a decreasing application of such harmonization according to the age and education of the speakersDoutoradoLinguisticaDoutor em Linguística140280/2012-06344/13-5CNPQCAPE

Synergies in innovation : lessons learnt from innovation ethics for responsible innovation

This paper draws on the emerging field of innovation ethics (IE) to complement the more established field of responsible innovation (RI) by focusing on key ethical issues raised by technological innovations. One key limitation of influential frameworks of RI is that they tend to neglect some key ethical issues raised by innovation, as well as major normative dimensions of the notion of responsibility. We explain how IE could enrich RI by stressing the more important role that ethical analysis should play in RI. We focus on two transversal issues of IE: the issue of redrawing conceptual boundaries, especially the topic of the artificialization of the world, and the issue of responsibility, especially the notion of total responsibility. We address these two issues from the thematic perspective of IE, thereby generating lessons learnt for RI. These two examples are taken as illustrations and blueprint of the dialogue that should take place between the two fields

Expressibility in the Lambda Calculus with Letrec

We investigate the relationship between finite terms in lambda-letrec, the lambda calculus with letrec, and the infinite lambda terms they express. As there are easy examples of lambda-terms that, intuitively, are not unfoldings of terms in lambda-letrec, we consider the question: How can those infinite lambda terms be characterised that are lamda-letrec-expressible in the sense that they can be obtained as infinite unfoldings of terms in lambda-letrec? For 'observing' infinite lambda-terms through repeated 'experiments' carried out at the head of the term we introduce two rewrite systems (with rewrite relations) -reg-> and -reg+-> that decompose the term, and produce 'generated subterms' in two notions. Thereby the sort of the step can be observed as well as its target, a generated subterm. In both systems there are four sorts of decomposition steps: -lambda-> steps (decomposing a lambda-abstraction), -@0> and -@1> steps (decomposing an application into its function and argument), and respectively, -del-> steps (delimiting the scope of an abstraction, for -reg->), and -S-> (delimiting of scopes, for -reg+->). These steps take place on infinite lambda-terms furnished with a leading prefix of abstractions for gathering previously encountered lambda-abstractions and keeping the generated subterms closed. We call an infinite lambda-term 'regular'/'strongly regular' if its set of -reg-> -reachable / -reg-> -reachable generated subterms is finite. Furthermore, we analyse the binding structure of lambda-terms with the concept of 'binding-capturing chain'. Using these concepts, we answer the question above by providing two characterisations of lambda-letrec-expressibility. For all infinite lambda-terms M, the following statements are equivalent: (i) M is lambda-letrec-expressible; (ii) M is strongly regular; (iii) M is regular, and it only has finite binding-capturing chains.Comment: 79 pages, 25 figure

Public health and the knowledge industry

El conocimiento desempeña papel importante en el cuidado de la salud. La producción y difusión del conocimiento en salud están actualmente cada vez más bajo control de intereses comerciales privados, caracterizados por conflictos de intereses que resultan en abusos de poder. A pesar de que esfuerzos considerables hayan sido dedicados al estudio del complejo médico-industrial y su papel en la producción de tales desequilibrios de poder y abusos consecuentes, poca atención ha sido dada al papel desempeñado por la industria de publicación, que puede estar sujeta a los mismos problemas. La idea ampliamente difundida de que "cambios importantes y frecuentes" ocurren en la medicina, aunque sin claro apoyo en evidencias, es una herramienta de marketing efectiva de las industrias farmacéutica e de la publicación, que se alimentan de la inseguridad de los médicos. La producción y distribución del conocimiento deberían ser abordadas como un componente estratégico de la salud pública.Knowledge plays an important role in health care. The production and diffusion of health-related knowledge are increasingly under the control of private commercial interests, which are characterized by conflicts of interests that result in abuses of power. Considerable research has been done on the medical-industrial complex and its role in the production of power imbalances and the consequent abuses, but little attention has been dedicated to the role played by the publishing industry, which can be subject to the same problems. The widely diffused idea that "frequent and major changes" occur in medicine, albeit unsupported by clearcut evidence, is an effective marketing tool for both the pharmaceutical and publishing industries, who feed and thrive on physicians' insecurities. The production and distribution of knowledge should be addressed as a strategic component of public health.O conhecimento desempenha papel importante no cuidado em saúde. A produção e difusão do conhecimento em saúde estão atualmente cada vez mais sob controle de interesses comerciais privados, caracterizados por conflitos de interesses que resultam em abusos de poder. Embora esforços consideráveis tenham sido dedicados ao estudo do complexo médico-industrial e seu papel na produção de tais desequilíbrios de poder e abusos conseqüentes, pouca atenção tem sido dada ao papel desempenhado pela indústria de publicação, que pode estar sujeita aos mesmos problemas. A idéia amplamente difundida de que "mudanças importantes e freqüentes" ocorrem na medicina, ainda que sem claro apoio em evidências, é uma ferramenta de marketing efetiva tanto da indústria farmacêutica quanto da de publicação, que alimentam a e se alimentam da insegurança dos médicos. A produção e distribuição do conhecimento deveriam ser abordadas como um componente estratégico da saúde pública