635 research outputs found

    Herbal highs: review on psychoactive effects and neuropharmacology

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    Background: A new trend among users of new psychoactive substances’ the consumption of “herbal highs”: plant parts containing psychoactive substances. Most of the substances extracted from herbs, in old centuries were at the centre of religious ceremonies of ancient civilizations. Currently, these herbal products are mainly sold by internet web sites and easily obtained since some of them have no legal restriction. Objective: We reviewed psychoactive effects and neuropharmacology of the most used “herbal highs” with characterized active principles, with studies reporting mechanisms of action, pharmacological and subjective effects, eventual secondary effects including intoxications and/or fatalities Method: The PubMed database was searched using the following key.words: herbal highs, Argyreia nervosa, Ipomoea violacea and Rivea corymbosa; Catha edulis; Datura stramonium; Piper methysticum; Mitragyna speciosa. Results: Psychoactive plants here reviewed have been known and used from ancient times, even if for some of them limited information still exist regarding subjective and neuropharmacological effects and consequent eventual toxicity when plants are used alone or in combination with “classical” drugs of abuse. Conclusion: Some “herbal highs” should be classified as harmful drugs since chronic administration has been linked with addiction and cognitive impairment; for some others taking into consideration only the recent trends of abuse, studies investigating these aspects are lacking

    A Model of Dynamic Resource Allocation in Workflow Systems

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    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

    Prediction of User-Brand Associations Based on Sentiment Analysis

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    Finding the right users to be chosen as targets for advertising campaigns is not a trivial task, and it may allow important commercial advantages. A novel approach is presented here for the recommendation of new possible consumers to brands interested in distributing advertising campaigns, ranked according to the “compatibility” between users and brands. A database containing both descriptions associated with different brands, and textual information about users' opinions on different topics, is required in input. Then, sentiment analysis techniques are applied to measure to what extent the users match with the brands, based on the texts associated with their opinions. The approach has been tested on both synthetic and real datasets, and with two different formulations, showing promising results in all the considered experiments

    High-resolution 40Ar/39Ar chronostratigraphy of the post-caldera (<20 ka) volcanic activity at Pantelleria, Sicily Strait

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    The island of Pantelleria (Sicily Strait), the type locality for pantellerite, has been the locus of major calderaforming eruptions that culminated, ca. 50 ka ago, in the formation of the Cinque Denti caldera produced by the Green Tuff eruption. The post-caldera silicic activity since that time has been mostly confined inside the caldera and consists of smaller-energy eruptions represented by more than twenty coalescing pantelleritic centers structurally controlled by resurgence and trapdoor faulting of the caldera floor. A high-resolution 40Ar/39Ar study was conducted on key units spanning the recent (post-20 ka) intracaldera activity to better characterize the present-day status (and forecast the short-term behavior of) the system based on the temporal evolution of the latest eruptions. The new 40Ar/39Ar data capture a long-term (N15 ka) decline in eruption frequency with a shift in eruptive pace from 3.5 ka−1 to 0.8 ka−1 associated with a prominent paleosol horizon marking the only recognizable volcanic stasis around 12–14 ka. This shift in extraction frequency occurswithoutmajor changes in eruptive style, and is paralleled by a subtle trend of decreasingmelt differentiation index. We speculate that this decline probably occurred (i) without short-term variations in melt production/differentiation rate in a steadystate compositionally-zoned silicic reservoir progressively tapped deeper through the sequence, and (ii) that it was possibly modulated by outboard eustatic forcing due to the 140 m sea level rise over the past 21 ka. The intracaldera system is experiencing a protracted stasis since 7 ka. Coupled with recent geodetic evidence of deflation and subsidence of the caldera floor, the system appears today to be on a wane with no temporal evidence for a short-term silicic eruption

    Modelling dialogues for optimal legislation

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    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

    The role of haptic feedback in video-Assisted thoracic surgery simulation training

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    technological advances on haptic devices, together with further studies focused on haptic feedback, be useful to develop efficient and effective training curricula and for establishing the value of simulators with haptic feedback in training and assessing thoracic surgical skills

    An overview of the geochemical characteristics of oceanic carbonatites: New insights from Fuerteventura carbonatites (Canary islands)

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    The occurrence of carbonatites in oceanic settings is very rare if compared with their continental counterpart, having been reported only in Cape Verde and Canary Islands. This paper provides an overview of the main geochemical characteristics of oceanic carbonatites, around which many debates still exist regarding their petrogenesis. We present new data on trace elements in minerals and whole-rock, together with the first noble gases isotopic study (He, Ne, Ar) in apatite, calcite, and clinopyroxene from Fuerteventura carbonatites (Canary Islands). Trace elements show a similar trend as Cape Verde carbonatites, almost tracing the same patterns on multi-element and REE abundance diagrams.3He/4He isotopic ratios of Fuerteventura carbonatites reflect a shallow (sub-continental lithospheric mantle, SCLM) He signature in their petrogenesis, and they clearly differ from Cape Verde carbonatites, i.e., fluids from a deep and low degassed mantle with a primitive plume-derived He signature are involved in their petrogenesis

    Diffuse and focused carbon dioxide and methane emissions from the Sousaki geothermal system, Greece

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    We report first data on chemical composition of the gas emitted by the geothermal system of Sousaki, Greece. Gas manifestations display typical geothermal gas composition with CO2 as the main component and CH4 and H2S as minor species. Soil gas composition derives from the mixing of two end-members (atmospheric air and geothermal gas). Soil CO2 fluxes range from&lt;2 to 33,400 g m2 d1. The estimated diffuse output of hydrothermal CO2, estimated for an area of 0.015 km2, is about 630 g s1, while a tentative estimation of CH4 diffuse output gave a value of about 1.15 g s
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