A computational framework for institutional agency

This paper provides a computational framework, based on Defeasible Logic, to capture some aspects of institutional agency. Our background is Kanger-Lindahl-P\"orn account of organised interaction, which describes this interaction within a multi-modal logical setting. This work focuses in particular on the notions of counts-as link and on those of attempt and of personal and direct action to realise states of affairs. We show how standard Defeasible Logic can be extended to represent these concepts: the resulting system preserves some basic properties commonly attributed to them. In addition, the framework enjoys nice computational properties, as it turns out that the extension of any theory can be computed in time linear to the size of the theory itself

Free choice permission in defeasible deontic logic

Free Choice Permission is one of the challenges for the formalisation of norms. In this paper, we follow a novel approach that accepts Free Choice Permission in a restricted form. The intuition behind the guarded form is strongly aligned with the idea of defeasibility. Accordingly, we investigate how to model the guarded form in Defeasible Deontic Logic extended with disjunctive permissions

Temporalised Normative Positions in Defeasible Logic

We propose a computationally oriented non-monotonic multi-modal logic arising from the combination of temporalised agency and temporalised normative positions. We argue about the defeasible nature of these notions and then we show how to represent and reason with them in the setting of Defeasible Logic

Argumentation Semantics for Temporal Defeasible Logic

We present an extension of the argumentation semantics for defeasible logic to cover the temporalisation of defeasible logic with permanent and imminent temporal literals

Renal involvement in psychological eating disorders

Psychological eating disorders--anorexia nervosa (AN), bulimia nervosa (BN), binge eating disorder--are an increasing public health problem with severe clinical manifestations: hypothermia, hypotension, electrolyte imbalance, endocrine disorders and kidney failure; they are of interest to nephrologists, but pathophysiological mechanisms in determining the renal involvement are still unclear. We describe pathophysiology, histological features and clinical manifestations of the most frequent psychological eating disorders: AN and BN. Regarding AN, we analyze the recent literature, and identify 3 principal pathways towards renal involvement: chronic dehydration-hypokalemia, nephrocalcinosis and chronic rhabdomyolysis. Regarding BN, we describe the correlation between obesity and many proinflammatory cytokines, chemokines, growth factors and adipokines, having potential metabolic and hemodynamic effects on the kidney and an important role in the pathogenesis of obesity-related renal injury, independently of hypertension and diabetes

A Model of Dynamic Resource Allocation in Workflow Systems

Current collaborative work environments are characterized by dynamically changing organizational structures. Although there have been several efforts to refine work distribution, especially in workflow management, most literature assumes a static database approach which captures organizational roles, groups and hierarchies and implements a dynamic roles based agent assignment protocol. However, in practice only partial information may be available for organizational models, and in turn a large number of exceptions may emerge at the time of work assignment. In this paper we present an organizational model based on a policy based normative system. The model is based on a combination of an intentional logic of agency and a flexible, but computationally feasible, non-monotonic formalism (Defeasible Logic). Although this paper focuses on the model specification, the proposed approach to modelling agent societies provides a means of reasoning with partial and unpredictable information as is typical of organizational agents in workflow system

The Cost of Social Agents

In this paper we follow the BOID (Belief, Obligation, Intention, Desire) architecture to describe agents and agent types in Defeasible Logic. We argue that the introduction of obligations can provide a new reading of the concepts of intention and intentionality. Then we examine the notion of social agent (i.e., an agent where obligations prevail over intentions) and discuss some computational and philosophical issues related to it. We show that the notion of social agent either requires more complex computations or has some philosophical drawbacks

Modelling dialogues for optimal legislation

This paper presents a framework for modelling legislative deliberation in the form of dialogues. Roughly, in legislative dialogues coalitions can dynamically change and propose rule-based theories associated with different utility functions, depending on the legislative theory the coalitions are trying to determine

Hypotheses and their dynamics in legal argumentation

We investigate some legal interpretation techniques from the viewpoint of the Argentinian jurisprudence. This allows the proposal of a logical framework –from a computer science perspective– for modeling such specific reasoning techniques towards an appropriate construction of legal arguments. Afterwards, we study the usage of assumptions towards construction of hypotheses. This is proposed in the dynamic context of legal procedures, where the referred argumentation framework evolves as part of the investigation instance prior to the trial. We propose belief revision operators to handle such dynamics, preserving a coherent behavior with regards to the legal interpretation used. Abduction is finally proposed to construct systematic hypothesization, with the objective to bring semi-automatic recommendations to push forward the investigation of a legal case

First measurements of the Fe oxidation state of spinel inclusions inolivine single crystals from Vulture (Italy) with the in situ synchrotronmicro-Mossbauer technique

The redox state of the Earth's upper mantle (i.e., oxygen fugacity, f(O2)) is a key variable that influences numerous processes occurring at depth like the mobility of volatile species, partial melting, and metasomatism. It is linked to the oxidation state of peridotite rocks, which is normally determined through the available oxythermobarometers after measuring the chemical composition of equilibrated rock-forming minerals and the Fe3+ in redox-sensitive minerals like spinel or garnet. To date, accurate measurements of Fe3+ / Sigma Fe in peridotites have been limited to those peridotites (e.g., harzburgites and lherzolites) for which an oxythermobarometer exists and where spinel (or garnet) crystals can be easily separated and measured by conventional Fe-57 Mossbauer spectroscopy. Wehrlitic rocks have been generally formed by the interaction of a lherzolite with carbonatitic melts and, therefore, have recorded the passage of (metasomatic) fluids at mantle conditions. However, no oxythermobarometer exists to determine their equilibrium f(O2).The aim of this study was to retrieve the f(O2) of the mantle beneath Mt. Vulture volcano (Italy) through the study of a wehrlitic lapillus emitted during the last eruption (similar to 140 kyr ago) that contain olivines with multiple tiny spinel inclusions with sizes < 40 mu m. To our knowledge, the Fe oxidation state of these inclusions has been never determined with the Mossbauer technique due to their small sizes.Here, we present measurements of the Fe3+ / Sigma Fe using in situ synchrotron Mossbauer spectroscopy coupled with chemical and spectroscopic analysis of both host olivine and spinel inclusions.The results show Fe3+ / Sigma Fe ratios of 0.03-0.05 for olivine and 0.40-0.45 for the included spinels, the latter of which appear higher than those reported in literature for mantle spinel harzburgites and lherzolites. Given the evidence of the mantle origin of the trapped spinels, we propose that the high f(O2) (between 0.81 and 1.00 log above the fayalite-magnetite-quartz buffer; FMQ) likely results from the interaction between the pristine spinel lherzolite and a CO2-rich metasomatic agent prior to the spinel entrapment in olivines at mantle depths