Characterizations of finite and infinite episturmian words via lexicographic orderings

In this paper, we characterize by lexicographic order all finite Sturmian and episturmian words, i.e., all (finite) factors of such infinite words. Consequently, we obtain a characterization of infinite episturmian words in a "wide sense" (episturmian and episkew infinite words). That is, we characterize the set of all infinite words whose factors are (finite) episturmian. Similarly, we characterize by lexicographic order all balanced infinite words over a 2-letter alphabet; in other words, all Sturmian and skew infinite words, the factors of which are (finite) Sturmian.Comment: 18 pages; to appear in the European Journal of Combinatoric

Reflections on Health Tourism and Cross-Border Health Care

Medical tourism is recognized as one of the oldest forms of tourism to obtain medical services and health care of high quality.1 It requires the realization of several services, such as coordination and cooperation between countries,2 to safeguard the right of access to quality care, the right to reimbursement for medical services, and the privacy of patients. A 2008 report forecasted that the number of medical tourists would rise from 750 000 in 2007 to between 5.25 and 6.25 million by 2010, and to between 10.5 and 23.2 million by 2017.3 Patients are informed consumers claiming the right to choose healthcare providers, including professionals, outside their national borders. In this research, patients are supported and encouraged by several factors, including use of the Internet and information about services and health professionals. Health tourism is under development in different countries4 and is spreading across the European Union as an example of cross-border healthcare. Directive 2011/24/EU,5,6 which has considered various aspects of cross-border care, recognizes the right of patients to receive healthcare in another member state and the right to reimbursement for medical care. The aim of this directive is to provide more legal certainties about the right to care in other European States. The directive is structured in three main areas: (1) identifying the member state responsible for ensuring observance of health care principles; (2) specifying the rights of patients to health care in another state; and (3) establishing a framework for European cooperatio

Current research on the effects of plastics pollution in marine and freshwater aquatic invertebrates

Plastics pollution in the aquatic environments represents one of the most critical worldwide issue. Every year, million tons of waste products are reversed both in marine and freshwaters, persisting for long timings and determining serious effects to living organisms. Here, these synthetic materials are fragmented in small particles, known as micro- and nanoplastics, under the effects of both biotic and abiotic factors. Due to their characteristics, smaller fragments are easier accumulated inside animal tissues and organs, risking to enter in the trophic chain. To date, despite the current situation, only a small amount of research has been conducted, especially on aquatic invertebrates, which can represent a suitable model for better analyzing the possible plastics dangerous effects. For this reason, in the present review we aim to collect the recent information about micro and nanoplastics effects on both marine and freshwaters invertebrates. In particular, we do not only focus the attention on the obtained results, but also, we report the main experimental methods and particle types used. Regardless of the heterogeneity present in literature, the actual data result fundamental for setting up the future research