Invariance: a Theoretical Approach for Coding Sets of Words Modulo Literal (Anti)Morphisms

Let $A$ be a finite or countable alphabet and let $\theta$ be literal (anti)morphism onto $A^*$ (by definition, such a correspondence is determinated by a permutation of the alphabet). This paper deals with sets which are invariant under $\theta$ ($\theta$-invariant for short).We establish an extension of the famous defect theorem. Moreover, we prove that for the so-called thin $\theta$-invariant codes, maximality and completeness are two equivalent notions. We prove that a similar property holds in the framework of some special families of $\theta$-invariant codes such as prefix (bifix) codes, codes with a finite deciphering delay, uniformly synchronized codes and circular codes. For a special class of involutive antimorphisms, we prove that any regular $\theta$-invariant code may be embedded into a complete one.Comment: To appear in Acts of WORDS 201

Two-Sided Derivatives for Regular Expressions and for Hairpin Expressions

The aim of this paper is to design the polynomial construction of a finite recognizer for hairpin completions of regular languages. This is achieved by considering completions as new expression operators and by applying derivation techniques to the associated extended expressions called hairpin expressions. More precisely, we extend partial derivation of regular expressions to two-sided partial derivation of hairpin expressions and we show how to deduce a recognizer for a hairpin expression from its two-sided derived term automaton, providing an alternative proof of the fact that hairpin completions of regular languages are linear context-free.Comment: 28 page

Small Universal Accepting Networks of Evolutionary Processors with Filtered Connections

In this paper, we present some results regarding the size complexity of Accepting Networks of Evolutionary Processors with Filtered Connections (ANEPFCs). We show that there are universal ANEPFCs of size 10, by devising a method for simulating 2-Tag Systems. This result significantly improves the known upper bound for the size of universal ANEPFCs which is 18. We also propose a new, computationally and descriptionally efficient simulation of nondeterministic Turing machines by ANEPFCs. More precisely, we describe (informally, due to space limitations) how ANEPFCs with 16 nodes can simulate in O(f(n)) time any nondeterministic Turing machine of time complexity f(n). Thus the known upper bound for the number of nodes in a network simulating an arbitrary Turing machine is decreased from 26 to 16

Electrochemical oxidation and detection of sodium urate in alkaline media on a copper oxides electrode

Electrochemical behaviour of copper oxides electrode in the presence of sodium urate was investigated. The correlation between the anodic oxidation and the amperometric detection of sodium urate in the alkaline medium on copper oxides electrode was analysed by cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS) measurements. The intereference from sodium tartrate presence in the aqueous alkaline solution was tested. Copper oxides electrodes can be used successfully for amperometric detection of both sodium urate and mixture of urate and tartrate as a cumulative response, in alkaline media, the target compound did not interfere each other. Journal of Applied Sciences and Environmental Management Vol. 10(1) 2006: 25-3

Electrochemical Oxidation and Detection of Sodium Urate in Alkaline Media on a Copper Oxides Electrode

Electrochemical behaviour of copper oxides electrode in the presence of sodium urate was investigated. The correlation between the anodic oxidation and the amperometric detection of sodium urate in the alkaline medium on copper oxides electrode was analysed by cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS) measurements. The intereference from sodium tartrate presence in the aqueous alkaline solution was tested. Copper oxides electrodes can be used successfully for amperometric detection of both sodium urate and mixture of urate and tartrate as a cumulative response, in alkaline media, the target compound did not interfere each other

Nanofibers

Cellulose is the most available biopolymer on earth existent in wood and other lignocellulosic sources, which can be isolated as nanofibers to reinforce composites. The aim of this chapter overview was to explain cellulose nanofibers’ preparation methods from different plant sources. The chemical treatment of cellulose fibers including dilute alkali swelling, acid and base hydrolysis, and bleaching was carried out followed by a mechanical method to isolate nanofibers. In this study, the effect of few palnt source variations and mechanical processes used in extraction procedure on nanofibers morphology, crystallinity, and chemical composition was evaluated. Characteristics of extracted cellulose nanofibers obtained from different plant sources were presented as well

On the ability of perfluorohexane sulfonate (PFHxS) bioaccumulation by two Pseudomonas sp. strains isolated from PFAS‐contaminated environmental matrices

PFASs (perfluoroalkyl and polyfluoroalkyl substances) are highly fluorinated, aliphatic, synthetic compounds with high thermal and chemical stability as well as unique amphiphilic properties which make them ingredients in a range of industrial processes. PFASs have attracted consideration due to their persistence, toxicity and bioaccumulation tendency in the environment. Recently, attention has begun to be addressed to shorter‐chain PFASs, such as perfluorohexane sulfonate [PFHxS], apparently less toxic to and more easily eliminated from lab animals. However, short‐chain PFASs represent end‐products from the transformation of fluorotelomers whose biotic breakdown reactions have not been identified to date. This means that such emergent pollutants will tend to accumulate and persist in ecosystems. Since we are just learning about the interaction between short‐chain PFASs and microorganisms, this study reports on the response to PFHxS of two Pseudomonas sp. strains isolated from environmental matrices contaminated by PFASs. The PFHxS bioaccumulation potential of these strains was unveiled by exploiting different physiological conditions as either axenic or mixed cultures under alkanothrofic settings. Moreover, electron microscopy revealed nonorthodox features of the bacterial cells, as a consequence of the stress caused by both organic solvents and PFHxS in the culturing substrate

On the Ability of Perfluorohexane Sulfonate (PFHxS) Bioaccumulation by Two Pseudomonas sp. Strains Isolated from PFAS-Contaminated Environmental Matrices

PFASs (perfluoroalkyl and polyfluoroalkyl substances) are highly fluorinated, aliphatic, synthetic compounds with high thermal and chemical stability as well as unique amphiphilic properties which make them ingredients in a range of industrial processes. PFASs have attracted consideration due to their persistence, toxicity and bioaccumulation tendency in the environment. Recently, attention has begun to be addressed to shorter-chain PFASs, such as perfluorohexane sulfonate [PFHxS], apparently less toxic to and more easily eliminated from lab animals. However, short-chain PFASs represent end-products from the transformation of fluorotelomers whose biotic breakdown reactions have not been identified to date. This means that such emergent pollutants will tend to accumulate and persist in ecosystems. Since we are just learning about the interaction between short-chain PFASs and microorganisms, this study reports on the response to PFHxS of two Pseudomonas sp. strains isolated from environmental matrices contaminated by PFASs. The PFHxS bioaccumulation potential of these strains was unveiled by exploiting different physiological conditions as either axenic or mixed cultures under alkanothrofic settings. Moreover, electron microscopy revealed nonorthodox features of the bacterial cells, as a consequence of the stress caused by both organic solvents and PFHxS in the culturing substrate

Efficient Enumeration of Non-Equivalent Squares in Partial Words with Few Holes

International audienceA partial word is a word with holes (also called don't cares: special symbols which match any symbol). A p-square is a partial word matching at least one standard square without holes (called a full square). Two p-squares are called equivalent if they match the same sets of full squares. Denote by psquares(T) the number of non-equivalent p-squares which are subwords of a partial word T. Let PSQUARES k (n) be the maximum value of psquares(T) over all partial words of length n with k holes. We show asympthotically tight bounds: c1 · min(nk 2 , n 2) ≤ PSQUARES k (n) ≤ c2 · min(nk 2 , n 2) for some constants c1, c2 > 0. We also present an algorithm that computes psquares(T) in O(nk 3) time for a partial word T of length n with k holes. In particular, our algorithm runs in linear time for k = O(1) and its time complexity near-matches the maximum number of non-equivalent p-squares

A switch from horizontal compression to vertical extension in the Vrancea slab explained by the volume reduction of serpentine dehydration

The Vrancea slab, Romania, is a subducted remnant of the Tethyan lithosphere characterized by a significant intermediate-depth seismicity (60–170 km). A recent study showed a correlation between this seismicity and major dehydration reactions, involving serpentine minerals up to 130 km depth, and high-pressure hydrated talc deeper. Here we investigate the potential link between the triggering mechanisms and the retrieved focal mechanisms of 940 earthquakes, which allows interpreting the depth distribution of the stress field. We observe a switch from horizontal compression to vertical extension between 100 and 130 km depth, where the Clapeyron slope of serpentine dehydration is negative. The negative volume change within dehydrating serpentinized faults, expected mostly sub-horizontal in the verticalized slab, could well explain the vertical extension recorded by the intermediate-depth seismicity. This apparent slab pull is accompanied with a rotation of the main compressive stress, which could favour slab detachments in active subduction zones