72 research outputs found

    Estimation of the hydraulic parameters of unsaturated samples by electrical resistivity tomography

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    In situ and laboratory experiments have shown that electrical resistivity tomography (ERT) is an effective tool to image transient phenomena in soils. However, its application in quantifying soil hydraulic parameters has been limited. In this study, experiments of water inflow in unsaturated soil samples were conducted in an oedometer equipped to perform three-dimensional electrical measurements. Reconstructions of the electrical conductivity at different times confirmed the usefulness of ERT for monitoring the evolution of water content. The tomographic reconstructions were subsequently used in conjunction with a finite-element simulation to infer the water retention curve and the unsaturated hydraulic conductivity. The parameters estimated with ERT agree satisfactorily with those determined using established techniques, hence the proposed approach shows good potential for relatively fast characterisations. Similar experiments could be carried out on site to study the hydraulic behaviour of the entire soil deposi

    INTEGRATING MULTIBAND PHOTOGRAMMETRY, SCANNING, AND GPR FOR BUILT HERITAGE SURVEYS: THE FAÇADES OF CASTELLO DEL VALENTINO

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    The conservation of built heritage is a complex process that necessitates co-operative efforts. Holistic, integrated documentation constitutes a crucial step towards conservation by contributing to diagnosis and by extension to the effective decision-making about the required preventive and restorative interventions. It involves the recording of interdisciplinary data to produce objective diagnostical conclusions concerning the state of preservation. Although the developments in close-range sensing techniques allow increasingly accurate and rich data recording for heritage building condition surveys, the problem of combining them (to allow integrated processing) often remains unsolved. This is particularly true when surveys include vastly heterogenous documentation data. This work aims to discuss methodologies and implications of such integrations through a monumental heritage survey case—the Castello del Valentino in Turin (Italy). Visible-spectrum and infrared imagery is combined with photogrammetric techniques, terrestrial LiDAR, and microwave measurements conducted on the historical façades’ surfaces, to examine the comprehensiveness of the data fusion results, as well as conclusions that can be drawn regarding previous interventions and the current condition of the monument

    Protocol for studying cough frequency in people with pulmonary tuberculosis.

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    INTRODUCTION: Cough is a key symptom of tuberculosis (TB) as well as the main cause of transmission. However, a recent literature review found that cough frequency (number of coughs per hour) in patients with TB has only been studied once, in 1969. The main aim of this study is to describe cough frequency patterns before and after the start of TB treatment and to determine baseline factors that affect cough frequency in these patients. Secondarily, we will evaluate the correlation between cough frequency and TB microbiological resolution. METHODS: This study will select participants with culture confirmed TB from 2 tertiary hospitals in Lima, Peru. We estimated that a sample size of 107 patients was sufficient to detect clinically significant changes in cough frequency. Participants will initially be evaluated through questionnaires, radiology, microscopic observation drug susceptibility broth TB-culture, auramine smear microscopy and cough recordings. This cohort will be followed for the initial 60 days of anti-TB treatment, and throughout the study several microbiological samples as well as 24 h recordings will be collected. We will describe the variability of cough episodes and determine its association with baseline laboratory parameters of pulmonary TB. In addition, we will analyse the reduction of cough frequency in predicting TB cure, adjusted for potential confounders. ETHICS AND DISSEMINATION: Ethical approval has been obtained from the ethics committees at each participating hospital in Lima, Peru, Asociación Benéfica PRISMA in Lima, Peru, the Universidad Peruana Cayetano Heredia in Lima, Peru and Johns Hopkins University in Baltimore, USA. We aim to publish and disseminate our findings in peer-reviewed journals. We also expect to create and maintain an online repository for TB cough sounds as well as the statistical analysis employed

    Caratterizzazione geofisica e monitoraggio microsismico di un ammasso roccioso instabile

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    Nella presente nota vengono illustrati i risultati preliminari della caratterizzazione geofisica e del monitoraggio microsismico dell'ammasso roccioso instabile di Madonna del Sasso (Verbania). I dati raccolti hanno permesso di meglio comprendere le ragioni dell'instabilità in atto, distinguendo chiaramente le frequenze fondamentali di vibrazione dell'ammasso instabile e le sue direzioni di oscillazione. Sono state inoltre stabilite utili correlazioni tra gli stessi parametri ed i fattori ambientali che influenzano l'ammasso ed un utile confronto in back analysis dei dati di monitoraggio geotecnico raccolti in passato sul medesimo sito

    Dynamics of Cough Frequency in Adults Undergoing Treatment for Pulmonary Tuberculosis.

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    Background: Cough is the major determinant of tuberculosis transmission. Despite this, there is a paucity of information regarding characteristics of cough frequency throughout the day and in response to tuberculosis therapy. Here we evaluate the circadian cycle of cough, cough frequency risk factors, and the impact of appropriate treatment on cough and bacillary load. Methods: We prospectively evaluated human immunodeficiency virus-negative adults (n = 64) with a new diagnosis of culture-proven, drug-susceptible pulmonary tuberculosis immediately prior to treatment and repeatedly until treatment day 62. At each time point, participant cough was recorded (n = 670) and analyzed using the Cayetano Cough Monitor. Consecutive coughs at least 2 seconds apart were counted as separate cough episodes. Sputum samples (n = 426) were tested with microscopic-observation drug susceptibility broth culture, and in culture-positive samples (n = 252), the time to culture positivity was used to estimate bacillary load. Results: The highest cough frequency occurred from 1 pm to 2 pm, and the lowest from 1 am to 2 am (2.4 vs 1.1 cough episodes/hour, respectively). Cough frequency was higher among participants who had higher sputum bacillary load (P < .01). Pretreatment median cough episodes/hour was 2.3 (interquartile range [IQR], 1.2-4.1), which at 14 treatment days decreased to 0.48 (IQR, 0.0-1.4) and at the end of the study decreased to 0.18 (IQR, 0.0-0.59) (both reductions P < .001). By 14 treatment days, the probability of culture conversion was 29% (95% confidence interval, 19%-41%). Conclusions: Coughs were most frequent during daytime. Two weeks of appropriate treatment significantly reduced cough frequency and resulted in one-third of participants achieving culture conversion. Thus, treatment by 2 weeks considerably diminishes, but does not eliminate, the potential for airborne tuberculosis transmission
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