Investigations on the sensitivity of the relationships between sound absorption characteristics and microstructure related parameters for polyurethane foams

International audienceStraightforward semi-phenomenological models have been developed for highly porous polyurethane foams to predict the macroscopic nonacoustic parameters involved in the classical Johnson-Champoux-Allard model (i.e., porosity, airflow resistivity...) from microstructure properties (i.e, strut length, strut thickness and reticulation rate). These microstructure properties are measured using sophisticated optical methods (i.e., optical microscope, SEM) and a large variability can be observed due to great complexity of the 3D microstructure; variability which also depends on the precision of the measurement device. This work investigates how the variability associated with the model inputs affects the model outputs (i.e., non-acoustic parameters, surface impedance and sound absorption coefficient). The sensitivity analysis is based on the Fourier Amplitude Sensitivity Test (FAST). It helps quantify the correlation between the input parameters and identify the parameters contributing the most to output variability, thus requiring precise measurement. This study illustrates the preponderant impact of the reticulation rate (i.e, open pore content) on acoustic performances and guides the user on the required optical measurement device

Coastal Scenic Quality Assessment of Moroccan Mediterranean Beaches: A Tool for Proper Management

This paper focuses on the study of landscape quality of Moroccan Mediterranean coastal areas, with a view to distinguishing exceptional beaches with high scenic value. The main characteristics of 50 beaches along the studied coast were assessed using a coastal scenic evaluation system based on a set of 26 selected parameters, including physical (18) and human (8) parameters. Each parameter was examined via a five-point rating scale, ranging from presence/absence or poor quality (1) to excellent quality (5). A decision index (D) is afterward obtained and used to classify sites into five classes: Class I: D >= 0.85, which included 9 sites (18%); Class II: 0.85 > D >= 0.65, 10 sites (20%); Class III: 0.65 > D >= 0.40, 8 sites (16%); Class IV: 0.40 > D >= 0.00, 16 sites (32%); and Class V: D < 0.00, 7 sites (14%). The sites of Belyounech 2, Maresdar, El Hwad, and Dalya are the best examples of Class I and represent extremely attractive coastal landscapes. The sites of Ghandouri, Tangier Municipal, M'Diq, Martil, and Tangier Malabata are examples of degraded urban sites that are very unattractive due to high human pressures. Management efforts in Moroccan coastal landscapes can strengthen the control of human activities and improve the scenic value of the sites. Class II beaches, such as Mrisat, Souani, Taourirt, and Sfiha, could improve and upgrade to Class I through litter cleaning and a regular maintenance program. Using the same principle, Class III sites, such as Sidi Amer O Moussa and Sidi Driss, could improve and upgrade to Class II. Indeed, litter and sewage appear as the main factors of degradation of Moroccan coasts, and many excellent beaches are strongly affected by them. This should be a wakeup call to the Moroccan authorities to take urgent and appropriate management measures

A review of post-incident studies for wildland-urban interface fires

Abstract Post-incident studies provide direct and valuable information to further the scientific understanding of Wildland-Urban Interface (WUI) fires. Most post-incident studies involve data collection in the field (i.e. a "research field deployment"). In this review, technical reports of post-incident studies for WUI fire and other natural disasters were analyzed and professionals directly involved in WUI fire research field deployments were interviewed. The goal of this review is to provide a resource for future WUI studies regarding the development of safe and effective fieldwork procedures, the collection and integration of accurate and relevant data, and the establishment of practical lessons learned. Three main stages of WUI fire post-incident studies are identified and described in detail. Data collection methodologies, data attributes, logistical practices and lessons-learned were compiled from various past studies and are presented here in the context of application to WUI fire

Modeling of laser-induced breakdown spectroscopic data analysis by an automatic classifier

Laser-induced breakdown spectroscopy (LIBS) is a multi-elemental and real-time analytical technique with simultaneous detection of all the elements in any type of sample matrix including solid, liquid, gas, and aerosol. LIBS produces vast amount of data which contains information on elemental composition of the material among others. Classification and discrimination of spectra produced during the LIBS process are crucial to analyze the elements for both qualitative and quantitative analysis. This work reports the design and modeling of optimal classifier for LIBS data classification and discrimination using the apparatus of statistical theory of detection. We analyzed the noise sources associated during the LIBS process and created a linear model of an echelle spectrograph system. We validated our model based on assumptions through statistical analysis of “dark signal” and laser-induced breakdown spectra from the database of National Institute of Science and Technology. The results obtained from our model suggested that the quadratic classifier provides optimal performance if the spectroscopy signal and noise can be considered Gaussian

Aortic remodelling in Fabry disease

Aims To evaluate thoracic aortic dilation in patients with Fabry disease (FD). Methods and results A cohort of 106 patients with FD (52 males; 54 females) from three European centres were studied. The diameter of the thoracic aorta was assessed at three levels (sinus of Valsalva, ascending aorta, and descending aorta) using echocardiograms and cardiovascular magnetic resonance imaging. Aortic dilation at the sinus of Valsalva was found in 32.7% of males and 5.6% of females; aneurysms were present in 9.6% of males and 1.9% of females. No aortic dilation was observed in the descending aorta. There was no correlation between aortic diameter at the sinus of Valsalva and cardiovascular risk factors. Conclusion Fabry disease should be considered as a cardiovascular disease that affects the heart and arterial vasculature, including the thoracic aorta. Thus, patients with FD should be closely monitored for the presence, and possible progression and complications of aortic dilation. Clinical Trial Registration: Protocol 101/01. Ethics committee, Faculty of Medicine, Lausann

Developing a Remotely Sensed Drought Monitoring Indicator for Morocco

Drought is one of the most serious climatic and natural disasters inflicting serious impacts on the socio-economy of Morocco, which is characterized both by low-average annual rainfall and high irregularity in the spatial distribution and timing of precipitation across the country. This work aims to develop a comprehensive and integrated method for drought monitoring based on remote sensing techniques. The main input parameters are derived monthly from satellite data at the national scale and are then combined to generate a composite drought index presenting different severity classes of drought. The input parameters are: Standardized Precipitation Index calculated from satellite-based precipitation data since 1981 (CHIRPS), anomalies in the day-night difference of Land Surface Temperature as a proxy for soil moisture, Normalized Difference Vegetation Index anomalies from Moderate Resolution Imaging Spectroradiometer (MODIS) data and Evapotranspiration anomalies from surface energy balance modeling. All of these satellite-based indices are being used to monitor vegetation condition, rainfall and land surface temperature. The weighted combination of these input parameters into one composite indicator takes into account the importance of the rainfall-based parameter (SPI). The composite drought index maps were generated during the growing seasons going back to 2003. These maps have been compared to both the historical, in situ precipitation data across Morocco and with the historical yield data across different provinces with information being available since 2000. The maps are disseminated monthly to several main stakeholders’ groups including the Ministry of Agriculture and Department of Water in Morocco

Organizing Gaussian mixture models into a tree for scaling up speaker retrieval

International audienceNumerous pattern recognition tasks set in the probabilistic framework face the following issue : it is expensive to evaluate the likelihood function for test data, when there are given very many candidate probabilistic models for explaining this data.We consider the application of this general and important problem to speaker recognition for indexing and retrieval purposes in radio archives.More precisely, we propose to reduce complexity at query time, by prior organization of speaker models into a hierarchy. This is very classically done for multi-dimensional vectors, but we propose herein a technique for building a hierarchy of probabilistic models, in the case these models take the form of a Gaussian mixture. From a closed-form approximation of Kullback-Leibler divergence between parent and children, an optimality criterion and an optimization technique are derived, from which we propose an efficient approach for building a tree of models, using clustering techniques (dendrogram-based or k-means-like). The proposed scheme is evaluated on real data

Standard survey methods for estimating colony losses and explanatory risk factors in Apis mellifera

This chapter addresses survey methodology and questionnaire design for the collection of data pertaining to estimation of honey bee colony loss rates and identification of risk factors for colony loss. Sources of error in surveys are described. Advantages and disadvantages of different random and non-random sampling strategies and different modes of data collection are presented to enable the researcher to make an informed choice. We discuss survey and questionnaire methodology in some detail, for the purpose of raising awareness of issues to be considered during the survey design stage in order to minimise error and bias in the results. Aspects of survey design are illustrated using surveys in Scotland. Part of a standardized questionnaire is given as a further example, developed by the COLOSS working group for Monitoring and Diagnosis. Approaches to data analysis are described, focussing on estimation of loss rates. Dutch monitoring data from 2012 were used for an example of a statistical analysis with the public domain R software. We demonstrate the estimation of the overall proportion of losses and corresponding confidence interval using a quasi-binomial model to account for extra-binomial variation. We also illustrate generalized linear model fitting when incorporating a single risk factor, and derivation of relevant confidence intervals

Nasal Epithelial Cells of Donor Origin after Allogeneic Hematopoietic Cell Transplantation are Generated at a Faster Rate in the First 3 Months Compared with Later Posttransplantation

Detection of donor-type epithelial cells (ECs) after allogeneic hematopoietic cell transplantation (allo-HCT) using XY chromosome fluorescein in situ hybridization (FISH) has suggested that hematopoietic stem cells carry a degree of developmental plasticity. This is controversial, given artifacts of XY-based detection and the possibility of hematopoietic–nonhematopoietic cell fusion. Moreover, the kinetics of donor-type ECs (quantity at different time points after transplant) is unknown. Here, we document unequivocally the existence of donor-type ECs using a method obviating the artifacts of XY-FISH and study their kinetics. Nasal scrapings and blood specimens were collected from 60 allo-HCT survivors between 7 days and 22 years posttransplantation. DNA extracted from laser-captured nasal ECs (ie, CK+CD45− cells) and blood leukocytes was polymerase chain reaction–amplified for a panel of 16 short tandem repeat markers. The median percentage of donor-type ECs (among nasal ECs) was 0% on day 7 posttransplantation, 2.8% at 3 months posttransplantation, and 8.5% at 12-22 years posttransplantation. Cell fusion was ruled out by FISH analysis for two autosomes. We conclude that donor-type nasal ECs exist after HCT, and that their percentage rises rapidly in the first 3 months posttransplantation and more slowly thereafter