876 research outputs found

    Flank instability at Mount Etna: testing the sensitivity of forward models to the internal structure

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    The deformation recorded at Mount Etna during the last 15 years clearly shows that there is an interplay between activity of magmatic sources and instability of the SE sector. In particular, the anomalous sliding of the SE flank can be triggered by summit or flank eruptions (e.g., 2002), but it is also observed during quiescent loading phases (e.g., 1993-1997). This deformation is usually modeled by sub-horizontal dislocation surfaces (embedded in an elastic half space) whose parameters are determined fitting the observed surface deformation. The purpose of this paper is to investigate whether models forced by a simple isotropic expansion source but taking into account the internal structure of Mount Etna are capable to focus a significant amount of horizontal deformation in the eastern flank. We perform computations based on the finite element method along a 2D cross section. The deformation models include both topography and a synthetic reconstruction of the internal layering constrained by geology, seismic tomography and experimental measurements of Etnean rocks. We study the sensitivity of the predicted surface displacement to variations of internal layers rheology and/or mechanical parameters. Our first results suggest that significant contributions to increase the deformation in the SE sector are due to plastic rheology of the clay layers and to asymmetrical distribution of elastic parameters related to the high velocity body underneath Mount Etna imaged by seismic tomography

    High-definition tDCS of the temporo-parietal cortex enhances access to newly learned words

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    Learning associations between words and their referents is crucial for language learning in the developing and adult brain and for language re-learning after neurological injury. Non-invasive transcranial direct current stimulation (tDCS) to the posterior temporo-parietal cortex has been suggested to enhance this process. However, previous studies employed standard tDCS set-ups that induce diffuse current flow in the brain, preventing the attribution of stimulation effects to the target region. This study employed high-definition tDCS (HD-tDCS) that allowed the current flow to be constrained to the temporo-parietal cortex, to clarify its role in novel word learning. In a sham-controlled, double-blind, between-subjects design, 50 healthy adults learned associations between legal non-words and unfamiliar object pictures. Participants were stratified by baseline learning ability on a short version of the learning paradigm and pairwise randomized to active (20 mins; N = 25) or sham (40 seconds; N = 25) HD-tDCS. Accuracy was comparable during the baseline and experimental phases in both HD-tDCS conditions. However, active HD-tDCS resulted in faster retrieval of correct word-picture pairs. Our findings corroborate the critical role of the temporo-parietal cortex in novel word learning, which has implications for current theories of language acquisition

    Sex Mediates the Effects of High-Definition Transcranial Direct Current Stimulation on “Mind-Reading”

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    Sex differences in social cognitive ability are well established, including measures of Theory of Mind (ToM). The aim of this study was to investigate if sex mediates the effects of high-definition transcranial direct current stimulation (HD-tDCS) administered to a key hub of the social brain (i.e., the dorsomedial prefrontal cortex, dmPFC) on the Reading the Mind in the Eyes Test (RMET). Forty healthy young adults (18–35 years) were randomly allocated to receive either anodal or cathodal HD-tDCS in sham HD-tDCS controlled, double blind designs. In each of the two sessions, subjects completed the RMET. Anodal stimulation to the dmPFC increased accuracy on the RMET in females only. To assure regional specificity we performed a follow-up study stimulating the right temporoparietal junction and found no effect in either sex. The current study is the first to show improved performance on the RMET after tDCS to the dmPFC in females only. The polarity-specific effects and use of focal HD-tDCS provide evidence for sex-dependent differences in dmPFC function in relation to the RMET. Future studies using tDCS to study or improve ToM, need to consider sex

    Tax Administrations’ Capacity in Preventing Tax Evasion and Tax Avoidance

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    FdR – Publicaties zonder aanstelling Universiteit Leide

    Effects of transcranial direct current stimulation on neural networks in young and older adults

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    Transcranial direct current stimulation (tDCS) may be a viable tool to improve motor and cognitive function in advanced age. However, although a number of studies have demonstrated improved cognitive performance in older adults, other studies have failed to show restorative effects. The neural effects of beneficial stimulation response in both age groups is lacking. In the current study, tDCS was administered during simultaneous fMRI in 42 healthy young and older participants. Semantic word generation and motor speech baseline tasks were used to investigate behavioral and neural effects of uni-and bihemispheric motor cortex tDCS in a three-way, crossover, sham tDCS controlled design. Independent components analysis assessed differences in task-related activity between the two age groups and tDCS effects. at the network level. We also explored whether laterality of language network organization was effected by tDCS. Behaviorally, both active tDCS conditions significantly improved semantic word retrieval performance in young and older adults and were comparable between groups and stimulation conditions. Network-level tDCS effects were identified in the ventral and dorsal anterior cingulate networks in the combined sample during semantic fluency and motor speech tasks. In addition, a shift toward enhanced left laterality was identified in the older adults for both active stimulation conditions. Thus, tDCS results in common network-level modulations and behavioral improvements for both age groups, with an additional effect of increasing left laterality in older adults

    Effectiveness of a Pharmacist-Directed Tdap Immunization Program for a University Campus

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    Background/Objectives: Despite a slight increase in Tdap immunization rates, the total numbers are still low among adults. The purpose of this study is to determine the impact of a pharmacist-directed immunization program. The primary objective was to assess the increase in vaccination rates among the subjects indicated to receive the Tdap vaccine. The secondary objective was to assess changes in pre and post vaccine knowledge scores.Methods: Employees enrolled in the pharmacist-directed employee wellness clinic on a university campus in Ohio were screened forTdap vaccination at the annual employee health fair during Fall of 2016. Results were cross-referenced with the state vaccination database. Subjects were recruited via email to an educational program. Indicated patients were asked to schedule an appointment with a pharmacist. Assessment data on the educational program was collected before the presentation and after the appointment when the vaccine was administered. The efficacy endpoint for the primary objective was a 20% increase in baseline vaccination rates.Results: Of the 198 subjects recruited, a total of 54 received Tdap vaccination. The baseline vaccination rate of the study populationwas 37.4% and increased by 27.2% after the intervention to a total vaccination rate of 64.6% (p< 0.001). Six knowledge assessmentswere utilized for the secondary objective; however, these results did not show significance.Conclusions: A pharmacist-directed Tdap immunization program is effective at increasing vaccination rates. Even though the changein education assessment data proved more observational, the education provided will empower subjects to make informed healthcaredecisions
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