260 research outputs found

    Improving the signal detection accuracy of functional Magnetic Resonance Imaging

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    Available online 12 April 2018A major drawback of functional Magnetic Resonance Imaging (fMRI) concerns the lack of detection accuracy of the measured signal. Although this limitation stems in part from the neuro-vascular nature of the fMRI signal, it also reflects particular methodological decisions in the fMRI data analysis pathway. Here we show that the signal detection accuracy of fMRI is affected by the specific way in which whole-brain volumes are created from individually acquired brain slices, and by the method of statistically extracting signals from the sampled data. To address these limitations, we propose a new framework for fMRI data analysis. The new framework creates whole-brain volumes from individual brain slices that are all acquired at the same point in time relative to a presented stimulus. These whole-brain volumes contain minimal temporal distortions, and are available at a high temporal resolution. In addition, statistical signal extraction occurred on the basis of a non-standard time point-by-time point approach. We evaluated the detection accuracy of the extracted signal in the standard and new framework with simulated and real-world fMRI data. The new slice-based data-analytic framework yields greatly improved signal detection accuracy of fMRI signals.See https://github.com/iamnielsjanssen/slice-based for a full analysis script using the Slice-Based method. This work was supported by The Spanish Ministry of Economy and Competitiveness (RYC2011-08433 and PSI2013-46334 to NJ)

    Comparison of systolic blood pressure measurements by auscultation and visual manometer needle jump

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    International Journal of Exercise Science 12(2): 214-220, 2019. Purpose: This study was designed to investigate differences in systolic blood pressure measurements as obtained through auscultation and observation of the visual jump on the manometer. Methods: Men (n = 21; 26.9 ± 7.4 yrs) and women (n = 22; 29.3 ± 13.9 yrs) volunteered to have resting systolic blood pressure (SBP) assessments. During the same cardiac inflation-deflation cycle of traditional sphygmomanometry, the initial visual jump of the manometer needle and first Korotkoff sound heard were recorded. Duplicate assessments were made in each arm with 30 sec between intra-arm trials. Results: Paired t-test results indicated there were no within-method differences between arms for visual jump (R: 132.1 ± 11.3; L: 131.8 ± 10.5 mmHg) or auscultation (R: 116.8 ± 9.0; L: 113.5 ± 8.8 mmHg). There were methodological differences within arm with visual jump being the higher of the two (right: t(42) = -12.69; left: t(42) = -11.37; p \u3c .001). Conclusion: If visual jump determination of SBP cannot be avoided, re-assessment using a more traditional method (i.e. auscultation) is recommended

    Impact of daily evaluation and spontaneous breathing test on the duration of pediatric mechanical ventilation: a randomized controlled trial

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    Objectives: To assess whether the combination of daily evaluation and use of a spontaneous breathing test could shorten the duration of mechanical ventilation as compared with weaning based on our standard of care. Secondary outcome measures included extubation failure rate and the need for noninvasive ventilation.Design: A prospective, randomized controlled trial.Setting: Two pediatric intensive care units at university hospitals in Brazil.Patients: the trial involved children between 28 days and 15 yrs of age who were receiving mechanical ventilation for at least 24 hrs.Interventions: Patients were randomly assigned to one of two weaning protocols. in the test group, the children underwent a daily evaluation to check readiness for weaning with a spontaneous breathing test with 10 cm H(2)O pressure support and a positive end-expiratory pressure of 5 cm H(2)O for 2 hrs. the spontaneous breathing test was repeated the next day for children who failed it. in the control group, weaning was performed according to standard care procedures.Measurements and Main Results: A total of 294 eligible children were randomized, with 155 to the test group and 139 to the control group. the time to extubation was shorter in the test group, where the median mechanical ventilation duration was 3.5 days (95% confidence interval, 3.0 to 4.0) as compared to 4.7 days (95% confidence interval, 4.1 to 5.3) in the control group (p = .0127). This significant reduction in the mechanical ventilation duration for the intervention group was not associated with increased rates of extubation failure or noninvasive ventilation. It represents a 30% reduction in the risk of remaining on mechanical ventilation (hazard ratio: 0.70).Conclusions: A daily evaluation to check readiness for weaning combined with a spontaneous breathing test reduced the mechanical ventilation duration for children on mechanical ventilation for > 24 hrs, without increasing the extubation failure rate or the need for noninvasive ventilation. (Crit Care Med 2011; 39: 2526-2533)Hosp Sirio Libanes, Intens Care Unit, São Paulo, BrazilUniv São Paulo, Sch Med, Dept Pediat, Hosp Clin, São Paulo, BrazilUniv São Paulo, Sch Med, Dept Pneumol, Hosp Clin, São Paulo, BrazilHosp Albert Einstein, Intens Care Unit, São Paulo, BrazilUniv Buenos Aires, Hosp Ninos R Gutierrez, Intens Care Unit, Buenos Aires, DF, ArgentinaUniv São Paulo, Sch Med, Intens Care Unit, Univ Hosp, São Paulo, BrazilWeb of Scienc

    Controlling magnetic order and quantum disorder in molecule-based magnets.

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    We investigate the structural and magnetic properties of two molecule-based magnets synthesized from the same starting components. Their different structural motifs promote contrasting exchange pathways and consequently lead to markedly different magnetic ground states. Through examination of their structural and magnetic properties we show that [Cu(pyz)(H 2 O)(gly) 2 ](ClO 4 ) 2 may be considered a quasi-one-dimensional quantum Heisenberg antiferromagnet whereas the related compound [Cu(pyz)(gly)](ClO 4 ) , which is formed from dimers of antiferromagnetically interacting Cu 2+ spins, remains disordered down to at least 0.03 K in zero field but shows a field-temperature phase diagram reminiscent of that seen in materials showing a Bose-Einstein condensation of magnons

    Controlling magnetic order and quantum disorder in molecule-based magnets

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    We investigate the structural and magnetic properties of two molecule-based magnets synthesized from the same starting components. Their different structural motifs promote contrasting exchange pathways and consequently lead to markedly different magnetic ground states. Through examination of their structural and magnetic properties we show that [Cu(pyz)(H2O)(gly)2](ClO4)2 may be considered a quasi-one-dimensional quantum Heisenberg antiferromagnet whereas the related compound [Cu(pyz)(gly)](ClO4), which is formed from dimers of antiferromagnetically interacting Cu2+ spins, remains disordered down to at least 0.03 K in zero field but shows a field-temperature phase diagram reminiscent of that seen in materials showing a Bose-Einstein condensation of magnons

    Eficacia y eficiencia de Leader 11 en Andalucía. Aproximación a un índice-resultado en materia de turismo rural

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    The evaluation has turned into a strategic element of differentiation, into the measurement into that allows to demonstrate his own beneficiaries, that the application of the public or private resources, it is as suitable as possible. To evaluate is necessary a system of indicators, which answer to five big types of which we will centre on two: efficiency (the effort inverted in terms of plysical, human or financial resources and the obtained results) and effectiveness (the impacts or results of the program with regard to his aims). In this article we try to put of manifest as the evaluation of the measurement B.3 (tourist activities) it allows across the analysis of the efficiency (projects) and the effectiveness (investment) in LEADER 11, one approximation in the construction of a proved index.La evaluación se ha convertido en un elemento estratégico de diferenciación, en la medida en que permite demostrar a sus propios beneficiarios, que la aplicación de los recursos públicos o privados, es la más adecuada posible. Para evaluar los programas de desarrollo rural es necesario un sistema de indicadores, que responden a cinco grandes tipos de los que nos centraremos en dos: eficiencia (el esfuerzo invertido en términos de recursos físicos, humanos o financieros y los resultados obtenidos) y eficacia (los impactos o resultados del programa respecto a sus objetivos). En este articulo tratamos de poner de manifiesto como la evaluación de la medida B.3 (actividades turísticas) permite, a través del análisis de la eficacia (proyectos) y la eficiencia (inversión) en LEADER 11, una primera aproximación en la construcción de un índice resultado
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