Search

P-Systems are abstract machines inspired to the behaviour of cells which we can see like simple biological processing units. Many types of P-Systems have been developed considering different aspects of the cells working principles, obtaining different computational models. In this paper we introduce Active P-Colonies (APC), a variant of the model P-Colony systems. P-Colony systems are a model of computation based on the collaboration among different agents placed in a shared passive environment (i.e. a space where no computing operations take place). First of all, we show that using the P-Colony system basic model it is not possible to solve problems in the computational class NP (unless P=NP). Inspired by what has been done for the basic variant of P-Systems, we extend the original model by including new types of rules and new biological behaviours like duplication and membrane dissolution. In fact, in APC the agents are able to duplicate themselves obtaining new processing units having the same computational power as the original unit. The cells can also dissolve their membrane, releasing the contents into the environment. The obtained systems are able to solve in polynomial time (and exponential space) computationally hard problems. In particular, we focus on the development of systems able to solve problems in the classes NP (SAT), coNP (UNSAT) and #P (#SAT).

Item does not contain fulltext, INTRODUCTION: Care for head and neck cancers is complex in particular for the rare ones. Knowledge is limited and histological heterogeneity adds complexity to the rarity. There is a wide consensus that to support clinical research on rare cancer, clinical registries should be developed within networks specializing in rare cancers. In the EU, a unique opportunity is provided by the European Reference Networks (ERN). The ERN EURACAN is dedicated to rare adults solid cancers, here we present the protocol of the EURACAN registry on rare head and neck cancers (ClinicalTrials.gov Identifier: NCT05483374). STUDY DESIGN: Registry-based cohort study including only people with rare head and neck cancers. OBJECTIVES: to help describe the natural history of rare head and neck cancers;to evaluate factors that influence prognosis;to assess treatment effectiveness;to measure indicators of quality of care. METHODS: Settings and participants It is an hospital based registry established in hospitals with expertise in head and neck cancers. Only adult patients with epithelial tumours of nasopharynx; nasal cavity and paranasal sinuses; salivary gland cancer in large and small salivary glands; and middle ear will be included in the registry. This registry won't select a sample of patients. Each patient in the facility who meets the above mentioned inclusion criteria will be followed prospectively and longitudinally with follow-up at cancer progression and / or cancer relapse or patient death. It is a secondary use of data which will be collected from the clinical records. The data collected for the registry will not entail further examinations or admissions to the facility and/or additional appointments to those normally provided for the patient follow-up. Variables Data will be collected on patient characteristics (eg. patient demographics, lifestyle, medical history, health status); exposure data (eg. disease, procedures, treatments of interest) and outcomes (e.g. survival, progressi