964 research outputs found

    Persuading the enemy: estimating the persuasive effects of partisan media with the preference-incorporating choice and assignment design

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    Does media choice cause polarization, or merely reflect it? We investigate a critical aspect of this puzzle: how partisan media contribute to attitude polarization among different groups of media consumers. We implement a new experimental design, called the Preference-Incorporating Choice and Assignment (PICA) design, that incorporates both free choice and forced exposure. We estimate jointly the degree of polarization caused by selective exposure and the persuasive effect of partisan media. Our design also enables us to conduct sensitivity analyses accounting for discrepancies between stated preferences and actual choice, a potential source of bias ignored in previous studies using similar designs. We find that partisan media can polarize both its regular consumers and inadvertent audiences who would otherwise not consume it, but ideologically-opposing media potentially also can ameliorate existing polarization between consumers. Taken together, these results deepen our understanding of when and how media polarize individuals.Accepted manuscrip

    The International Trade Network in Space and Time

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    This paper studies how the structure of the International Trade Network (ITN) changes in geographical space and along time. We employ geographical distance between countries in the world to filter the links in the ITN, building a sequence of sub-networks, each one featuring trade links occurring at similar distance. We then test if the topological properties of ITN subnetworks change as distance increases. We find that distance strongly impacts, in non-linear ways, the topology of the ITN. We show that the ITN is disassortative at long distances while it is assortative at short ones. Similarly, the main determinant of the overall high ITN clustering level are triangular trade triples between geographically close countries. This means that trade partnership choices are differentiated over different distance ranges. Such evidence robustly arises over time and after one controls for the economic size and income of trading partners

    Toward the automation of threat modeling and risk assessment in IoT systems

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    The Internet of Things (IoT) has recently become one of the most relevant emerging technologies in the IT landscape. IoT systems are characterized by the high heterogeneity of involved architectural components (e.g., device platforms, services, networks, architectures) and involve a multiplicity of application domains. In the IoT scenario, the identification of specific security requirements and the security design are very complex and expensive tasks, since they heavily depend on the configuration deployment actually in place and require security experts. In order to overcome these issues, we propose an approach aimed at supporting the security analysis of an IoT system by means of an almost completely automated process for threat modeling and risk assessment, which also helps identify the security controls to implement in order to mitigate existing security risks. We demonstrate the effectiveness of the approach by discussing its application to a home automation system, built on top of commercial IoT products

    Effects of fungal root infection on the vigor of grapevines infested by root-feeding grape phylloxera

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    The role of fungal pathogens in damage of grapevines (Vitis vinifera L.; cv. Chardonnay) associated with grape phylloxera (Daktulosphaira vitifoliae FITCH) was investigated. Seven different genera of secondary fungi were isolated from surface-disinfected feeding sites of phylloxera but none from surface-disinfected root tissues undamaged by phylloxera. Damage in vines infested with phylloxera and infected with Fusarium solani (MART.) or with F. solani and Pythium ultimum TROW. was significantly greater than damage in vines infested with phylloxera only. In a greenhouse experiment, total biomass was reduced by 16% in vines infested with phylloxera and 24 to 29% in vines infested with phylloxera and infected with fungus in comparison with control vines. Chlorophyll content, average internode length, shoot biomass, and root biomass in the uninfested, uninfected vines were significantly greater than vines infested with phylloxera or vines infested with phylloxera and infected with F. solani or P. ultimum, or both. Preventative treatment with metalaxyl, benomyl or copper quinolinolate fungicides significantly decreased damage in phylloxera-infested vines in comparison with untreated vines. The implications of this research with respect to management of grape phylloxera are discussed

    Pharmacokinetics and antinociceptive effects of tramadol and its metabolite O-desmethyltramadol following intravenous administration in sheep

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    Although sheep are widely used as an experimental model for various surgical procedures there is a paucity of data on the pharmacokinetics and efficacy of analgesic drugs in this species. The aims of this study were to investigate the pharmacokinetics of intravenously (IV) administered tramadol and its active metabolite O-desmethyltramadol (M1) and to assess the mechanical antinociceptive effects in sheep. In a prospective, randomized, blinded study, six healthy adult sheep were given 4 and 6\u2009mg/kg tramadol and saline IV in a cross-over design with a 2-week wash-out period. At predetermined time points blood samples were collected and physiological parameters and mechanical nociceptive threshold (MNT) values were recorded. The analytical determination of tramadol and M1 was performed using high performance liquid chromatography. Pharmacokinetic parameters fitted a two- and a non-compartmental model for tramadol and M1, respectively. Normally distributed data were analysed by a repeated mixed linear model. Plasma concentration vs. time profiles of tramadol and M1 were similar after the two doses. Tramadol and M1 plasma levels decreased rapidly in the systemic circulation, with both undetectable after 6\u2009h following drug administration. Physiological parameters did not differ between groups; MNT values were not statistically significant between groups at any time point. It was concluded that although tramadol and M1 concentrations in plasma were above the human minimum analgesic concentration after both treatments, no mechanical antinociceptive effects of tramadol were reported. Further studies are warranted to assess the analgesic efficacy of tramadol in sheep

    A methodology for the development of a Hinged Ankle-Foot Orthosis compatible with natural joint kinematics

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    This work presents a new concept to design Hinged Ankle-Foot Orthoses (HAFOs), based on the definition of a special mechanical articulation able to mimic the physiological behavior of the human ankle joint. Current commercial braces typically do not take into account the natural variability of the ankle joint axis. As the hinge location as well as the rotation axis variability are both relevant for the overall function of the device, and strongly depend on the subject-specific characteristics, a methodology for the development of a HAFO with a floating axis of rotation, based on the in-vivo kinematic analysis of the ankle joint, is here proposed. The kinematic analysis was performed by calculation of the instantaneous and mean helical axes over the collected stereo-photogrammetric data of joint motion. This procedure was tested on a healthy subject, leading to the design and fabrication of a first customized prototype of the orthosis. The performance of this HAFO was experimentally verified by motion analysis. All relevant results are presented, and further possible future improvements of the procedure are discussed

    The Effect of Cromolyn Sodium and Nedocromil Sodium Administered by A pressurized Aerosol with A spacer Device on Exercise-Induced Asthma in Children

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    To compare the effectiveness of cromolyn sodium (CS) (10 mg) and nedocromil sodium (NS) (4 mg) administered by a metered dose inhaler (MDI) with a spacer device in preventing exercise-induced asthma (EIA), eight asthmatic children with EIA were studied in a randomized double-blind, cross-over, placebo-controlled study, CS and NS provided significant, comparable protection from EIA and both were better than placebo. We conclude that CS and NS administered by a pressurized aerosol with a spacer device provide equal protection against EIA in children
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