On Varieties of Ordered Automata

The Eilenberg correspondence relates varieties of regular languages to pseudovarieties of finite monoids. Various modifications of this correspondence have been found with more general classes of regular languages on one hand and classes of more complex algebraic structures on the other hand. It is also possible to consider classes of automata instead of algebraic structures as a natural counterpart of classes of languages. Here we deal with the correspondence relating positive $\mathcal C$-varieties of languages to positive $\mathcal C$-varieties of ordered automata and we present various specific instances of this correspondence. These bring certain well-known results from a new perspective and also some new observations. Moreover, complexity aspects of the membership problem are discussed both in the particular examples and in a general setting

Te conto poemas

The Creation section has the objective of publish unpublished texts and materials by writers and/or artists, photographers, designers, as well as unpublished documents found in the USP IEB Archive. “I tell you poems” gathers two tales by Jé Oliveira, “Zoom nos ouvidos e nos olhos” and “As águas e os olhos”. Actor, director, playwright and writer, Oliveira is one of the founders of Coletivo Negro. With this group, he published the book Negras dramaturgias (Coletivo Negro, 2015). The text of the play Farinha com açúcar ou sobre a sustança de meninos e homens (Javali, 2018), which he wrote, was a semi-finalist for the Oceanos award in 2019.  A seção Criação tem por objetivo publicar textos e materiais inéditos de escritores e/ou artistas, fotógrafos, desenhistas, além de documentos inéditos encontrados no Arquivo do IEB/USP. “Te conto poemas” reúne dois textos de Jé Oliveira, “Zoom nos ouvidos e nos olhos” e “As águas e os olhos”. Ator, diretor, dramaturgo e escritor, Oliveira é um dos fundadores do Coletivo Negro. Publicou, com o grupo, o livro Negras dramaturgias (COLETIVO NEGRO, 2015). O texto do espetáculo teatral Farinha com açúcar ou sobre a sustança de meninos e homens (OLIVEIRA, 2018), de sua autoria, foi semifinalista do prêmio Oceanos em 2019

Green's Relations in Finite Transformation Semigroups

We consider the complexity of Green's relations when the semigroup is given by transformations on a finite set. Green's relations can be defined by reachability in the (right/left/two-sided) Cayley graph. The equivalence classes then correspond to the strongly connected components. It is not difficult to show that, in the worst case, the number of equivalence classes is in the same order of magnitude as the number of elements. Another important parameter is the maximal length of a chain of components. Our main contribution is an exponential lower bound for this parameter. There is a simple construction for an arbitrary set of generators. However, the proof for constant alphabet is rather involved. Our results also apply to automata and their syntactic semigroups.Comment: Full version of a paper submitted to CSR 2017 on 2016-12-1

Arithmetical Congruence Preservation: from Finite to Infinite

Various problems on integers lead to the class of congruence preserving functions on rings, i.e. functions verifying $a-b$ divides $f(a)-f(b)$ for all $a,b$. We characterized these classes of functions in terms of sums of rational polynomials (taking only integral values) and the function giving the least common multiple of $1,2,\ldots,k$. The tool used to obtain these characterizations is "lifting": if $\pi\colon X\to Y$ is a surjective morphism, and $f$ a function on $Y$ a lifting of $f$ is a function $F$ on $X$ such that $\pi\circ F=f\circ\pi$. In this paper we relate the finite and infinite notions by proving that the finite case can be lifted to the infinite one. For $p$-adic and profinite integers we get similar characterizations via lifting. We also prove that lattices of recognizable subsets of $Z$ are stable under inverse image by congruence preserving functions

On Decidability of Intermediate Levels of Concatenation Hierarchies

It is proved that if definability of regular languages in the Sigma(n) fragment of the first-order logic on finite words is decidable, then it is decidable also for the Delta(n+1) fragment. In particular, the decidability for Delta(5) is obtained. More generally, for every concatenation hierarchy of regular languages, it is proved that decidability of one of its half levels implies decidability of the intersection of the following half level with its complement

Synchronization Problems in Automata without Non-trivial Cycles

We study the computational complexity of various problems related to synchronization of weakly acyclic automata, a subclass of widely studied aperiodic automata. We provide upper and lower bounds on the length of a shortest word synchronizing a weakly acyclic automaton or, more generally, a subset of its states, and show that the problem of approximating this length is hard. We investigate the complexity of finding a synchronizing set of states of maximum size. We also show inapproximability of the problem of computing the rank of a subset of states in a binary weakly acyclic automaton and prove that several problems related to recognizing a synchronizing subset of states in such automata are NP-complete.Comment: Extended and corrected version, including arXiv:1608.00889. Conference version was published at CIAA 2017, LNCS vol. 10329, pages 188-200, 201

Plasmonic Band Structure Controls Single-Molecule Fluorescence

A chieving a complete manipulation of the generally weak optical signal from a single quantum emitter is a key objective in nanophotonics. To this end, two major routes have been investigated: plasmonic metal nanostructures 1À11 and dielectric photonic crystals. 12À21 Both routes have demonstrated breakthrough results in tailoring the photoluminescence intensity, spectrum, or directionality of single emitters. The plasmonic approach has put the most emphasis on the nanoscale antenna element to control single-emitter radiation 1,2,22À24 via the strong electromagnetic enhancement in the near field of metals. In contrast, the photonic crystal approach centers on the use of coherent scattering to boost the interaction strength of intrinsically weakly scattering building blocks. State-of-the-art structures use thin highindex membranes perforated by nanoapertures, in which the guided modes fold into a complex band structure. Spontaneous emission control then revolves around the targeted coupling of an emitter to select Bloch modes, with well-controlled outcoupling characteristics. Very recently, interest has emerged in the interplay between these two approaches, implying the use of a coherent array of plasmonic resonators to shape the luminescence emission properties. Two key examples are provided on one hand by the use of diffractive modes in 2D arrays of plasmon particles to shape emission of thin emissive layers 10,11,25À27 and on the other hand by the demonstration of YagiÀUda antennas with a single quantum dot emitter in the optical regime, 3 where coherent near -field coupling between scattering nanoparticles is determinant to achieve directional emission. 6 Here, we investigate the emergence of coherent antenna array effects to shape the fluorescence emission of single molecules in finite-sized bidimensional arrays of apertures milled into a metal film that supports surface plasmon guided modes. Transmission properties of quasi-infinite aperture arrays and single holes have been thoroughly investigated in the framework of extraordinary optical transmission. Henzie. Received for review June 28, 2013 and accepted September 10, 2013. Published online 10.1021/nn4033008 ABSTRACT Plasmonics and photonic crystals are two complementary approaches to tailor singleemitter fluorescence, using strong local field enhancements near metals on one hand and spatially extended photonic band structure effects on the other hand. Here, we explore the emergence of spontaneous emission control by finite-sized hexagonal arrays of nanoapertures milled in gold film. We demonstrate that already small lattices enable highly directional and enhanced emission from single fluorescent molecules in the central aperture. Even for clusters just four unit cells across, the directionality is set by the plasmonic crystal band structure, as confirmed by full-wave numerical simulations. This realization of plasmonic phase array antennas driven by single quantum emitters opens a flexible toolbox to engineer fluorescence and its detection

Influence of Substituents on the Energy and Nature of the Lowest Excited States of Heteroleptic Phosphorescent Ir(III) Complexes: A Joint Theoretical and Experimental Study

Abstract: A series of Ir(III)-based heteroleptic complexes with phenylpyridine (ppy) and 2-(5-phenyl-4H-[1,2,4]triazol-3-yl)-pyridine (ptpy) derivatives as coordinating ligands has been characterized by a number of experimental and theoretical techniques. Density functional theory (DFT) calculations were able to reproduce and rationalize the experimental redox and excited-states properties of the Ir complexes under study. The introduction of fluorine and trifluoromethyl substituents is found not only to modulate the emission energy but also often to change the ordering of the lowest excited triplet states and hence their localization. The lowest triplet states are best characterized as local excitations of one of the chromophoric ligands (ppy or ptpy). The admixture of metal-to-ligand charge-transfer (MLCT) and ligand-to-ligand charge-transfer (LLCT) character is small and strongly depends on the nature of the excited state; their role is, however, primordial in defining the radiative decay rate of the complexes. The extent of charge-transfer contributions depends on the energy gaps between the relevant molecular orbitals, which can be modified by the substitution pattern

Prey preferences among the community of deep-diving odontocetes from the Bay of Biscay, Northeast Atlantic.

a b s t r a c t Long-finned pilot whales (Globicephala melas), Risso's dolphins (Grampus griseus), melon-headed whales (Peponocephala electra), Cuvier's beaked whales (Ziphius cavirostris), Sowerby's beaked whales (Mesoplodon bidens), northern bottlenose whales (Hyperoodon ampullatus), sperm whales (Physeter macrocephalus), dwarf sperm whales (Kogia sima) and pygmy sperm whales (Kogia breviceps) make up the large community of deep-diving odontocetes occurring off the Bay of Biscay, northeast Atlantic. The ecology of these toothed cetaceans is poorly documented worldwide. The present study described their prey preferences from stomach content analysis and showed resource partitioning within the assemblage. The majority of the species appeared to be mostly teutophageous. Fish was an important food source only for the Sowerby's beaked whale and, to a lesser extent, for the long-finned pilot whale. In terms of foraging habitats inferred from prey composition, either pelagic oceanic or demersal neritic habitats were exploited by toothed whales in the Bay of Biscay, with only the long-finned pilot whale foraging in the two habitats. Finally, with more than 14,000 identified cephalopods from 39 species, the present study highlighted also the poorly known deep-sea cephalopod community off the Bay of Biscay using top predators as biological samplers

The metabolic syndrome: similar deleterious impact on all-cause mortality in hypertensive and normotensive subjects

Objectives Few data are available on the impact of the metabolic syndrome on all-cause mortality risk according to the presence of hypertension. Our aim was to evaluate the 5-year impact of the metabolic syndrome, according to blood pressure status, on all-cause mortality risk in a large French population. Methods The study population included 39 998 men and 20 756 women with no personal history of cardiovascular disease, who had a health check-up at the IPC Center (Paris, France) between 1999 and 2002, and who were followed up for 4.7 W 1.2 years. The metabolic syndrome was defined according to the National Cholesterol Educational Program classification (2001). Cox regression models were used to evaluate risk of all-cause mortality after adjustment for age, sex, classical risk factors and socioeconomic categories. Subjects were classified according to blood pressure status: hypertensive subject (systolic blood pressure > -140 mmHg and/or diastolic blood pressure > -90 mmHg or treatment) and normotensive subject. Results The risk of all-cause mortality associated with the metabolic syndrome was 1.50 (1.24-1.82) [hazard ratio (HR) (95% confidence interval)]. The risk of all-cause mortality associated with the presence of hypertension was 1.60 (1.38-1.85). During the 4.7 years of follow-up, the impact of the metabolic syndrome was similar among normotensive and hypertensive subjects [HR: 1.09 (0.68-1.75) and 1.40 (1.13-1.74), respectively, P for interaction U 0.35]. Conclusion The findings from this study show that, in a large middle-aged French population, the metabolic syndrome has the same deleterious impact on all-cause mortality in hypertensive subjects and normotensive subjects