Automata Constructions for LTL with Past

Linear temporal logic (LTL) is a popular language in formal verification, especially in the domains of model checking and reactive synthesis. Because its semantics is defined in terms of infinite sequences of symbols that can be interpreted as system variables, it is suitable for expressing how the state of a continuously operating system evolves over time. Due to the tight connection between the semantics of LTL and that of automata over infinite words, and because many common approaches to formal verification are automata-theoretic in nature, it is not surprising that various translations from LTL to automata over infinite words have been developed over the years, both for theoretical and practical purposes. Although many properties are naturally and succinctly expressed in terms of past events, the majority of these translations are restricted to formulae that only refer to the present and future. Those that do handle past are often indirect or lead to automata with an unnecessarily large number of states. In this thesis we present several translations from linear temporal logic with past to various types of automata over infinite words. We also suggest a framework for extending existing tools that are based on manipulating LTL formulae to handle past, together with a prototype tool intended to serve as a proof of this concept

Women, men and coronary heart disease: a review of the qualitative literature

Aim. This paper presents a review of the qualitative literature which examines the experiences of patients with coronary heart disease. The paper also assesses whether the experiences of both female and male patients are reflected in the literature and summarizes key themes. Background. Understanding patients' experiences of their illness is important for coronary heart disease prevention and education. Qualitative methods are particularly suited to eliciting patients' detailed understandings and perceptions of illness. As much previous research has been 'gender neutral', this review pays particular attention to gender. Methods. Published papers from 60 qualitative studies were identified for the review through searches in MEDLINE, EMBASE, CINAHL, PREMEDLINE, PsychINFO, Social Sciences Citation Index and Web of Science using keywords related to coronary heart disease. Findings. Early qualitative studies of patients with coronary heart disease were conducted almost exclusively with men, and tended to generalize from 'male' experience to 'human' experience. By the late 1990s this pattern had changed, with the majority of studies including women and many being conducted with solely female samples. However, many studies that include both male and female coronary heart disease patients still do not have a specific gender focus. Key themes in the literature include interpreting symptoms and seeking help, belief about coronary 'candidates' and relationships with health professionals. The influence of social roles is important: many female patients have difficulties reconciling family responsibilities and medical advice, while male patients worry about being absent from work. Conclusions. There is a need for studies that compare the experiences of men and women. There is also an urgent need for work that takes masculinity and gender roles into account when exploring the experiences of men with coronary heart disease

Thermal stress induces glycolytic beige fat formation via a myogenic state.

Environmental cues profoundly affect cellular plasticity in multicellular organisms. For instance, exercise promotes a glycolytic-to-oxidative fibre-type switch in skeletal muscle, and cold acclimation induces beige adipocyte biogenesis in adipose tissue. However, the molecular mechanisms by which physiological or pathological cues evoke developmental plasticity remain incompletely understood. Here we report a type of beige adipocyte that has a critical role in chronic cold adaptation in the absence of β-adrenergic receptor signalling. This beige fat is distinct from conventional beige fat with respect to developmental origin and regulation, and displays enhanced glucose oxidation. We therefore refer to it as glycolytic beige fat. Mechanistically, we identify GA-binding protein α as a regulator of glycolytic beige adipocyte differentiation through a myogenic intermediate. Our study reveals a non-canonical adaptive mechanism by which thermal stress induces progenitor cell plasticity and recruits a distinct form of thermogenic cell that is required for energy homeostasis and survival

Peroxisome Proliferator Activated Receptor Gamma Controls Mature Brown Adipocyte Inducibility through Glycerol Kinase.

Peroxisome proliferator-activated receptors (PPARs) have been suggested as the master regulators of adipose tissue formation. However, their role in regulating brown fat functionality has not been resolved. To address this question, we generated mice with inducible brown fat-specific deletions of PPARα, β/δ, and γ, respectively. We found that both PPARα and β/δδ are dispensable for brown fat function. In contrast, we could show that ablation of PPARγ in vitro and in vivo led to a reduced thermogenic capacity accompanied by a loss of inducibility by β-adrenergic signaling, as well as a shift from oxidative fatty acid metabolism to glucose utilization. We identified glycerol kinase (Gyk) as a partial mediator of PPARγ function and could show that Gyk expression correlates with brown fat thermogenic capacity in human brown fat biopsies. Thus, Gyk might constitute the link between PPARγ-mediated regulation of brown fat function and activation by β-adrenergic signaling

A Direct Translation from LTL with Past to Deterministic Rabin Automata

We present a translation from linear temporal logic with past to deterministic Rabin automata. The translation is direct in the sense that it does not rely on intermediate non-deterministic automata, and asymptotically optimal, resulting in Rabin automata of doubly exponential size. It is based on two main notions. One is that it is possible to encode the history contained in the prefix of a word, as relevant for the formula under consideration, by performing simple rewrites of the formula itself. As a consequence, a formula involving past operators can (through such rewrites, which involve alternating between weak and strong versions of past operators in the formula’s syntax tree) be correctly evaluated at an arbitrary point in the future without requiring backtracking through the word. The other is that this allows us to generalize to linear temporal logic with past the result that the language of a pure-future formula can be decomposed into a Boolean combination of simpler languages, for which deterministic automata with simple acceptance conditions are easily constructed

The Role of the Mucus Barrier in Digestion

Mucus forms a protective layer across a variety of epithelial surfaces. In the gastrointestinal (GI) tract, the barrier has to permit the uptake of nutrients, while excluding potential hazards, such as pathogenic bacteria. In this short review article, we look at recent literature on the structure, location, and properties of the mammalian intestinal secreted mucins and the mucus layer they form over a wide range of length scales. In particular, we look at the structure of the gel-forming glycoprotein MUC2, the primary intestinal secreted mucin, and the influence this has on the properties of the mucus layer. We show that, even at the level of the protein backbone, MUC2 is highly heterogeneous and that this is reflected in the networks it forms. It is evident that a combination of charge and pore size determines what can diffuse through the layer to the underlying gut epithelium. This information is important for the targeted delivery of bioactive molecules, including nutrients and pharmaceuticals, and for understanding how GI health is maintained

ppLTLTT : Temporal Testing for Pure-Past Linear Temporal Logic Formulae

This paper presents ppLTLTT, a tool for translating pure-past linear temporal logic formulae into temporal testers in the form of automata. We show how ppLTLTT can be used to easily extend existing LTL-based tools, such as LTL-to-automata translators and reactive synthesis tools, to support a richer input language. Namely, with ppLTLTT, tools that accept LTL input are also made to handle pure-past LTL as atomic formulae. While the addition of past operators does not increase the expressive power of LTL, it opens up the possibility of writing more intuitive and succinct specifications. We illustrate this intended use of ppLTLTT for Slugs, Strix, and Spot ’s command line tool LTL2TGBA by describing three corresponding wrapper tools pSlugs, pStrix, and pLTL2TGBA, that all leverage ppLTLTT. All three wrapper tools are designed to seamlessly fit this paradigm, by staying as close to the respective syntax of each underlying tool as possible

Hessian Fly in Texas Wheat.

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Adipocyte browning and higher mitochondrial function in peri-adrenal but not subcutaneous fat in pheochromocytoma

Context: Patients with pheochromocytoma (pheo) show presence of multilocular adipocytes that express uncoupling protein (UCP) 1 within periadrenal (pADR) and omental (OME) fat depots. It has been hypothesized that this is due to adrenergic stimulation by catecholamines produced by the pheo tumors. Objective: To characterize the prevalence and respiratory activity of brown-like adipocytes within pADR, OME and subcutaneous (SC) fat depots in human adult pheo patients. Design: This was an observational cohort study. Setting: University hospital. Patients: We studied 46 patients who underwent surgery for benign adrenal tumors (21pheos and 25 controls with adrenocortical adenomas). Main outcome measure: We characterized adipocyte browning in pADR, SC, and OME fat depots for histological and immunohistological features, mitochondrial respiration rate, and gene expression. We also determined circulating levels of catecholamines and other browning-related hormones. Results: 11 of 21 pheo pADR adipose samples, but only 1 of 25 pADR samples from control patients, exhibited multilocular adipocytes. The pADR browning phenotype was associated with higher plasma catecholamines and raised UCP1. Mitochondria from multilocular pADR fat of pheo patients exhibited increased rates of coupled and uncoupled respiration. Global gene expression analysis in pADR fat revealed enrichment in β-oxidation genes in pheo patients with multilocular adipocytes. No SC or OME fat depots exhibited aspects of browning. Conclusion: Browning of the pADR depot occurred in half of pheo patients and was associated with increased catecholamines and mitochondrial activity. No browning was detected in other fat depots, suggesting that other factors are required to promote browning in these depots