Sublinearly space bounded iterative arrays

Iterative arrays (IAs) are a, parallel computational model with a sequential processing of the input. They are one-dimensional arrays of interacting identical deterministic finite automata. In this note, realtime-lAs with sublinear space bounds are used to accept formal languages. The existence of a proper hierarchy of space complexity classes between logarithmic anel linear space bounds is proved. Furthermore, an optimal spacc lower bound for non-regular language recognition is shown. Key words: Iterative arrays, cellular automata, space bounded computations, decidability questions, formal languages, theory of computatio

Latvian Quantum Finite State Automata for Unary Languages

We design Latvian quantum finite state automata (LQFAs for short) recognizing unary regular languages with isolated cut point 1/2. From an architectural point of view, we combine two LQFAs recognizing with isolated cut point, respectively, the finite part and the ultimately periodic part of any given unary regular language L. In both modules, we use a component addressed in the literature and here suitably adapted to the unary case, to discriminate strings on the basis of their length. The number of basis states and the isolation around the cut point of the resulting LQFA for L exponentially depends on the size of the minimal deterministic finite state automaton for L.Comment: In Proceedings NCMA 2023, arXiv:2309.0733

Autonomic cardiovascular control and cardiac arrhythmia in two pregnant women with hypertrophic cardiomyopathy: Insights from ICD monitoring

In women with hypertrophic cardiomyopathy (HCM), pregnancy prompts major changes in hemodynamic and cardiac autonomic function that may precipitate heart failure (HF) or increase the risk of cardiac arrhythmia.We report the clinical follow-up of two patients with non-obstructive HCM implanted with a cardioverter defibrillator (ICD) allowing for continuous analysis of heart rate (HR), heart rate variability (HRV) and cardiac arrhythmia throughout the entire course of pregnancy.Both patients experienced increased HR and decreased HRV from the early stages of pregnancy, which persisted until delivery. Premature ventricular contractions (PVCs) and runs of non-sustained ventricular tachycardia (NSVT) reached a peak in the second and third trimesters, concurrent with sympathetic hyperactivity. In one patient with baseline NYHA class II HF symptoms, increased PVCs and NSVT were consistent with the deterioration of HF, supporting the decision to bring the delivery forward. While both patients experienced a persistent increase in sympathetic tone and ventricular ectopic activity, no life-threatening arrhythmias were documented.During pregnancy, patients with hypertrophic cardiomyopathy develop progressive neuroautonomic imbalance, prompting an increase in non-sustained ventricular arrhythmia. This enhanced arrhythmia burden warrants close follow-up and rhythm assessment during the third trimester, especially in women who have heart failure symptoms before pregnancy. Implantable cardioverter defibrillators provide a continuous analysis of heart rate variability and arrhythmia burden that supports therapeutic decision-making during follow-up. Resumo: Em mulheres com miocardiopatia hipertrófica, a gravidez aumenta as variações hemodinâmicas e as alterações da função autonómica cardíaca que podem provocar insuficiência cardíaca ou aumentar o risco de arritmia. Reportamos o acompanhamento clínico de duas pacientes com miocardiopatia hipertrófica não obstrutiva, ambas implantadas com cardioversor-desfibrilhador (CID). A monitoração com CID permite a análise contínua da frequência cardíaca, da variabilidade da frequência cardíaca (VFC) e da arritmia durante toda a gravidez. As duas pacientes manifestaram aumentos da FC e diminuições da VFC desde o início da gravidez até ao parto. Observou-se um pico de frequência de extrassístoles ventriculares (EV) e de taquicardias ventriculares não sustentadas (TVNS) no segundo e terceiro trimestres da gestação, em correspondência da hiperatividade simpática. Numa das pacientes com classe funcional NYHA II, antes da gravidez, o aumento de EV e de TVNS contemporaneamente ao agravamento da insuficiência cardíaca levou à decisão de antecipar o parto. As duas pacientes demonstraram um aumento persistente da atividade simpática e da atividade ectópica ventricular, não existiram casos de arritmias ventriculares malignas. Durante a gravidez as pacientes com miocardiopatia hipertrófica desenvolvem um progressivo desequilíbrio autonómico que causa um aumento das arritmias ventriculares não sustentadas. O aumento do risco arrítmico necessita de um constante e frequente controle clínico e do ritmo cardíaco durante o terceiro trimestre, especialmente em mulheres com sintomas de insuficiência cardíaca antes da gravidez. O cardioversor-desfibrilhador implantável fornece uma análise continua da variabilidade da frequência cardíaca e das arritmias que podem apoiar as decisões terapêuticas durante a gravidez. Keywords: Hypertrophic cardiomyopathy, Pregnancy, Implantable cardioverter defibrillator, Heart rate variability, Ventricular arrhythmia, Palavras-chave: Miocardiopatia hipertrófica, Gravidez, Cardioversor-desfibrilhador implantável, Variabilidade da frequência cardíaca, Arritmia ventricula

Left ventricular remodeling in hypertrophic cardiomyopathy: an overview of current knowledge

While most patients with hypertrophic cardiomyopathy (HCM) show a relatively stable morphologic and clinical phenotype, in some others, progressive changes in the left ventricular (LV) wall thickness, cavity size, and function, defined, overall, as "LV remodeling", may occur. The interplay of multiple pathophysiologic mechanisms, from genetic background to myocardial ischemia and fibrosis, is implicated in this process. Different patterns of LV remodeling have been recognized and are associated with a specific impact on the clinical course and management of the disease. These findings underline the need for and the importance of serial multimodal clinical and instrumental evaluations to identify and further characterize the LV remodeling phenomenon. A more complete definition of the stages of the disease may present a chance to improve the management of HCM patients

Threshold Circuits for Iterated Matrix Product and Powering

The complexity of computing, via threshold circuits, the iterated product and powering of fixed-dimension $k\times k$ matrices with integer or rational entries is studied. We call these two problems $\sf IMP_k$ and $\sf MPOW_k$, respectively, for short. We prove that: (i) For $k\geq2$, $\sf IMP_k$ does not belong to ${\rm TC}^0$, unless ${\rm TC}^0={\rm NC}^1$.newline (ii) For stochastic matrices : $\sf IMP_2$ belongs to ${\rm TC}^0$ while, for $k\geq3$, $\sf IMP_k$ does not belong to ${\rm TC}^0$, unless ${\rm TC}^0={\rm NC}^1$. (iii) For any k, $\sf MPOW_k$ belongs to ${\rm TC}^0$

Quantum finite automata with control language

Bertoni et al.  introduced in Lect. Notes Comput. Sci. 2710 (2003) 1–20 a new model of 1-way quantum finite automaton (1qfa) called 1qfa with control language (1qfc). This model, whose recognizing power is exactly the class of regular languages, generalizes main models of 1qfa's proposed in the literature. Here, we investigate some properties of 1qfc's. In particular, we provide algorithms for constructing 1qfc's accepting the inverse homomorphic images and quotients of languages accepted by 1qfc's. Moreover, we give instances of binary regular languages on which 1qfc's are proved to be more succinct (i.e. , to have less states) than the corresponding classical (deterministic) automata

Computational and Descriptional Power of Nondeterministic Iterated Uniform Finite-State Transducers

An iterated uniform finite-state transducer (IUFST) runs the samelength-preserving transduction, starting with a sweep on the input string andthen iteratively sweeping on the output of the previous sweep. The IUFSTaccepts the input string by halting in an accepting state at the end of asweep. We consider both the deterministic (IUFST) and nondeterministic (NIUFST)version of this device. We show that constant sweep bounded IUFSTs and NIUFSTsaccept all and only regular languages. We study the state complexity ofremoving nondeterminism as well as sweeps on constant sweep bounded NIUFSTs,the descriptional power of constant sweep bounded IUFSTs and NIUFSTs withrespect to classical models of finite-state automata, and the computationalcomplexity of several decidability questions. Then, we focus on non-constantsweep bounded devices, proving the existence of a proper infinite nonregularlanguage hierarchy depending on the sweep complexity both in the deterministicand nondeterministic case. Though NIUFSTss are "one-way" devices we show thatthey characterize the class of context-sensitive languages, that is, thecomplexity class DSpace(lin). Finally, we show that the nondeterministicdevices are more powerful than their deterministic variant for a sublinearnumber of sweeps that is at least logarithmic