Welfare of fish

Η ευζωία των ψαριών και γενικότερα όλων των ζώων είναι μια έννοια που δηλώνει μια ανώδυνη και μη οτρεσογόνα κατάσταση διαβίωσης. Τέτοια έννοια, αν και τα προηγούμενα χρόνια είχε πολλές φορές αμφισβητηθεί από τους παράγωγους, θεσμοθετείται πλέον αυστηρά από πολλές χώρες. Για τα ψάρια, λίγα είναι τα παραδείγματα τέτοιας θεσμοθέτησης, όπως, για παράδειγμα, στη Νορβηγία και στη Γερμανία η θανάτωση για ανθρώπινη κατανάλωση πρέπει να πραγματοποιείται βασιζόμενη σε συγκεκριμένες τεχνικές, συμβατές με την ευζωία των ψαριών. Όλα τα ζώα χρειάζονται μια σταθερότητα του περιβάλλοντος διαβίωσης προκειμένου να επιβιώσουν, να αναπτυχθούν και να αναπαραχθούν .Η μη εξασφάλιση τέτοιας σταθερότητας ορίζεται ως κατάσταση στρες. Στα ψάρια, οι αιτίες που μπορούν να τους προκαλέσουν στρες είναι ποικίλες. Πρώτον, σχεδόν όλοι οι χειρισμοί που πραγματοποιούνται σε επίπεδο ιχθυοκαλλιέργειας θεωρούνται στρεσογόνοι (π.χ. μεταφορά). Δεύτερον, οι ακατάλληλες συνθήκες εκτροφής, π.χ. η υψηλή ιχθυοπυκνότητα και ένα μη ισορροπημένο σιτηρέσιο, θέτουν σε αμφισβήτηση την ευζωία των ψαριών. Στοίδιο αποτέλεσμα οδηγούν και άλλοι παράγοντες, όπως η ακατάλληλη ποιότητα του νερού εκτροφής, οι τεχνικές που χρησιμοποιούνται για την πρόληψη και θεραπεία ασθενειών, οι τεχνικές θανάτωσης και η μεταφορά.Fish welfare and in general the welfare of animals is a term that declares a painless and not stressfull state of being. During the previous years this term has been questioned by the producers, however, nowadays, it is actually legally regulated in several countries. For fishes, few are the examples of such enforcement, such as in Norway and Germany where the killing of fish for human consumption bases on techniques compatible with their welfare. All the animals need a stable environment of being so that they can survive, develop and reproduce. The absence of such a stability is termed as stress. There are various causes of producing stress in fish. Firsdy, almost all management procedures that are practiced commercially result in stress (e.g. transport). Secondly, inadequate conditions of farming, such as the high stocking-density and an unbalanced food, place the welfare of fishes at risk. To the same result may also lead other factors, such as the unsuitable quality of the rearing water, the techniques that are used for the prevention and treatment of illnesses, the techniques of killing and also transport

Changing a semantics: opportunism or courage?

The generalized models for higher-order logics introduced by Leon Henkin, and their multiple offspring over the years, have become a standard tool in many areas of logic. Even so, discussion has persisted about their technical status, and perhaps even their conceptual legitimacy. This paper gives a systematic view of generalized model techniques, discusses what they mean in mathematical and philosophical terms, and presents a few technical themes and results about their role in algebraic representation, calibrating provability, lowering complexity, understanding fixed-point logics, and achieving set-theoretic absoluteness. We also show how thinking about Henkin's approach to semantics of logical systems in this generality can yield new results, dispelling the impression of adhocness. This paper is dedicated to Leon Henkin, a deep logician who has changed the way we all work, while also being an always open, modest, and encouraging colleague and friend.Comment: 27 pages. To appear in: The life and work of Leon Henkin: Essays on his contributions (Studies in Universal Logic) eds: Manzano, M., Sain, I. and Alonso, E., 201

Set optimization - a rather short introduction

Recent developments in set optimization are surveyed and extended including various set relations as well as fundamental constructions of a convex analysis for set- and vector-valued functions, and duality for set optimization problems. Extensive sections with bibliographical comments summarize the state of the art. Applications to vector optimization and financial risk measures are discussed along with algorithmic approaches to set optimization problems

Untyping Typed Algebras and Colouring Cyclic Linear Logic

We prove "untyping" theorems: in some typed theories (semirings, Kleene algebras, residuated lattices, involutive residuated lattices), typed equations can be derived from the underlying untyped equations. As a consequence, the corresponding untyped decision procedures can be extended for free to the typed settings. Some of these theorems are obtained via a detour through fragments of cyclic linear logic, and give rise to a substantial optimisation of standard proof search algorithms.Comment: 21

Boolean like algebras

Using Vaggione’s concept of central element in a double pointed algebra, we introduce the notion of Boolean like variety as a generalization of Boolean algebras to an arbitrary similarity type. Appropriately relaxing the requirement that every element be central in any member of the variety, we obtain the more general class of semi-Boolean like varieties, which still retain many of the pleasing properties of Boolean algebras. We prove that a double pointed variety is discriminator i↵ it is semi-Boolean like, idempotent, and 0-regular. This theorem yields a new Maltsev-style characterization of double pointed discriminator varieties. Moreover, we show that every idempotent semi-Boolean-like variety is term equivalent to a variety of noncommutative Boolean algebras with additional regular operations