501 research outputs found

    Competition between Visual Events Modulates the Influence of Salience during Free-Viewing of Naturalistic Videos

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    In daily life the brain is exposed to a large amount of external signals that compete for processing resources. The attentional system can select relevant information based on many possible combinations of goal-directed and stimulus-driven control signals. Here, we investigate the behavioral and physiological effects of competition between distinctive visual events during free-viewing of naturalistic videos. Nineteen healthy subjects underwent functional magnetic resonance imaging (fMRI) while viewing short video-clips of everyday life situations, without any explicit goal-directed task. Each video contained either a single semantically-relevant event on the left or right side (Lat-trials), or multiple distinctive events in both hemifields (Multi-trials). For each video, we computed a salience index to quantify the lateralization bias due to stimulus-driven signals, and a gaze index (based on eye-tracking data) to quantify the efficacy of the stimuli in capturing attention to either side. Behaviorally, our results showed that stimulus-driven salience influenced spatial orienting only in presence of multiple competing events (Multi-trials). fMRI results showed that the processing of competing events engaged the ventral attention network, including the right temporoparietal junction (R TPJ) and the right inferior frontal cortex. Salience was found to modulate activity in the visual cortex, but only in the presence of competing events; while the orienting efficacy of Multi-trials affected activity in both the visual cortex and posterior parietal cortex (PPC). We conclude that in presence of multiple competing events, the ventral attention system detects semantically-relevant events, while regions of the dorsal system make use of saliency signals to select relevant locations and guide spatial orienting

    Inverse Estimation of Temperature Profiles in Landfills Using Heat Recovery Fluids Measurements

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    In addition to leachate and gas emission analysis, temperature variations in municipal solid waste landfills are routinely monitored for safety and health reasons, such as the increased production of biogas or the danger of spontaneous combustion phenomena if the temperature exceeds 70–75°C. The increasing constraints on greenhouse gas emissions and the convenience of fuel and heat recovery have helped develop a global approach to landfills' operation and maintenance, generally referred to as bioreactor landfill management. The heat recovery piping we are presently designing can be a significant part of this approach. The heat gained by a fluid circulated in a closed network through the landfill is transferred to an external heat exchanger or used directly as warm water. Additionally, it can help reduce landfill temperature levels and control biogas generation. Since the pipes diameter is large enough to allow for a radial temperature gradient, this information can be used for an inverse estimation of the temperature profile in the landfill which constitutes the boundary conditions of the resulting heat transfer problem. In this paper, we describe an algorithm for regularising the resulting ill-posed free boundary estimation problem using sampled data of the heat recovery fluid on exiting the landfill

    Make Bow-tie Dynamic by Rethinking it as a Hierarchical Bayesian Network. Dynamic Risk Assessment of an LNG Bunkering Operation

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    In the present era, the spread of cyber-physical systems in the framework of the so-called Industry 4.0, is leading towards a complete automation of industrial processes, which are increasingly decentralized, smart, and require fewer and fewer frontline personnel. The risk assessment process is certainly not excluded from the revolution, and in perspective needs to be automatic, dynamic and linked with the conditions that emerge, moment by moment, in the life of a complex system. Analytical techniques can help in converting data in information and hence system knowledge to spot trends in operational performance, thus improving risk assessment quality. Even though the bow-tie approach is widely used within the context of complex systems, it still evidences several limitations, mainly connected to the actual assessment of likelihood and interdependencies in the fault and event trees. This paper shows how a bow tie analysis can be reframed as a Hierarchical Bayesian Network, where the probability distributions of the network nodes are updated with real time predictions during the operations. The proposed model was then applied to the risk assessment of a shore-to-ship LNG bunkering operation

    Comparative prediction of cardiac events by wall motion, wall motion plus coronary flow reserve, or myocardial perfusion analysis: a multicenter study of contrast stress echocardiography

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    ObjectivesThis study sought to determine whether the increasing difficulty of assessing wall motion (WM), Doppler coronary flow reserve on the left anterior descending coronary artery (CFR-LAD), and myocardial perfusion (MP) during stress echocardiography (SE) was justified by increasing prognostic information in patients with known or suspected coronary artery disease.BackgroundThe use of echocardiographic contrast agents during SE permits the assessment of both CFR-LAD and MP, but their relative incremental prognostic value is undefined.MethodsThis study followed a multicenter cohort of 718 patients for 16 months after high-dose dipyridamole contrast SE for evaluation of known or suspected coronary artery disease. The ability of WM, CFR-LAD, and MP to predict cardiac events was studied by multivariable models and risk reclassification.ResultsAbnormal SE was detected as a reversible WM abnormality in 18%, reversible MP defect in 27%, and CFR-LAD <2 in 38% of subjects. Fifty cardiac events occurred (annualized event rate 6.0%). A normal MP stress test had a 1-year hard event rate of 1.2%. The C-index of outcomes prediction based on clinical data was improved with MP (p < 0.001) and WM/CFR-LAD (p = 0.037), and MP (p = 0.003) added to clinical and WM data. Net risk reclassification was improved by adding MP (p < 0.001) or CFR-LAD (net reclassification improvement p = 0.001) in addition to clinical and WM data. The model including clinical data, WM/CFR-LAD, and MP performed better than that without MP did (p = 0.012).ConclusionsThe multiparametric assessment of WM, CFR-LAD and MP during stress testing in patients with known or suspected coronary artery disease is feasible. Contrast SE allowed better prognostication, irrespective of the use of CFR-LAD or MP. The addition of either CFR-LAD or MP assessment to standard WM analysis and clinical parameters yielded progressively higher values for the prediction of cardiac events and may be required in today's intensively treated patients undergoing SE, because their average low risk of future cardiac events requires methods with higher predictive sensitivity than that available with standalone WM assessment

    Reasoning deficits among illicit drug users are associated with aspects of cannabis use

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    Background. Deficits in deductive reasoning have been observed among ecstasy/polydrug users. The present study seeks to investigate dose-related effects of specific drugs and whether these vary with the cognitive demands of the task. Methods. One hundred and five participants (mean age 21.33, S.D. 3.14; 77 females, 28 males) attempted to generate solutions for eight one-model syllogisms and one syllogism for which there was no valid conclusion (NVC). All of the one model syllogisms generated at least one valid conclusion and six generated two valid conclusions. In these six cases one of the conclusions was classified as common and the other as non-common. Results. The number of valid common inferences was negatively associated with aspects of short term cannabis use and with measures of IQ. The outcomes observed were more than simple post intoxication effects since cannabis use in the 10 days immediately before testing was unrelated to reasoning performance. Following adjustment for multiple comparisons, the number of non-common valid inferences was not significantly associated with any of the drug use measures. Conclusions. Recent cannabis use appears to impair the processes associated with generating valid common inferences while not affecting the production of non-common inferences. It is possible, therefore, that the two types of inference may recruit different executive resources which may differ in their susceptibility to cannabis-related effects

    Long term results of single high dose Stereotactic Body Radiotherapy in the treatment of primary lung tumors

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    Stereotactic body radiotherapy (SBRT) is a standard treatment for inoperable early-stage NSCLC, with local control rates comparable to surgical series. Promising results have been achieved utilizing a high single-dose schedule. The aim of our study was to evaluate long-term local control and toxicity in a series of patients treated with SBRT delivered in a single dose of 30 Gy. 44 patients affected by early stage NSCLC were treated with SBRT delivered in a single dose of 30 Gy. Survival and prognostic factors were retrospectively evaluated. Median follow-up was 34 months (range 3–81). Three- and 5-year local progression-free survival (LPFS) were 87.8% and 87.8% respectively (median 30 months; range 6–81 months), 3- and 5-year OS and CSS were 64.9% and 36.9%, 80.9% and 65.5%, respectively. Two (4.6%) cases of grade 3 pneumonitis occurred. At the univariate analysis lesion diameter ≤ 25 mm was predictive of better 5-year LPFS (95.8% versus 56.3%; p = 0.003) and 5-year PFS (69.8% versus 27.8%; p = 0.002). The results of our study indicated a high local control, survival and tolerability after a long-term follow-up with the use of SBRT 30 Gy single dose. Further prospective studies could better define the role of this regimen

    FluoroSpot assay to analyze SARS-CoV-2-specific T cell responses

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    Monitoring antigen-specific T cell frequency and function is essential to assess the host immune response to severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection. Here, we present a FluoroSpot assay for concurrently detecting ex vivo antiviral cytokine production by SARS-CoV-2-specific T cells following peptide stimulation. We then detail intracellular cytokine staining by flow cytometry to further validate the FluoroSpot assay results and define the specific T cell subpopulations. For complete details on the use and execution of this protocol, please refer to Tiezzi et al. (2023).

    Disc coablation and epidural injection of steroids: a comparison of strategies in the treatment of mechanical spinal discogenic pain

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    Summary In this study two strategies in the treatment of Mechanical Spinal Discogenic Pain have been compared: Disc Coablation and Epidural Injection of Steroids. In 2003 50 patients treated with one or two epidural injections have been selected &apos;&apos;ad random&apos;&apos; and 50 patients treated with disc coablation. Comparison of the data indicated an improvement of average VAS when relaxed for both groups Ă°p &lt; 0:01Ăž, while after slightmoderate strain, this value was significant only after coablation Ă°p &lt; 0:001Ăž. Finally, average VAS was clearly lower Ă°p &lt; 0:01Ăž after coablation as compared to epidural injections
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