A prospective study was carried out on 92 randomly selected beef herds in the Midi-Pyrenees region in France. The objective was to determine factors associated with time to neonatal gastroenteritis. By taking into account the "intra-herd" correlation in failure time (in the semiparametric Cox model), we identified 12 management risk factors associated with hazard of diarrhoea. Some previously have been identified, but "new" risk factors were feeding of corn silage and the incidence of diarrhoea in the last season. We used the two main approaches which are often reviewed: marginal and frailty Cox models. Our results show that these two models give different parameter estimates, so the choice of the model remains crucial.

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Pavement deterioration models are important inputs for pavement management systems (PMS). These models are based on the study of performance data, and they provide the evolution law of pavement deterioration. Performance data consist of observations of pavement section conditions, and are collected through several follow-up campaigns on road networks. To characterize the pavement deterioration process, several statistical methods have been developed at the Laboratoire Central des Ponts et Chaussées (LCPC). However, these methods are suboptimal for modeling the evolution of pavement deterioration, as they ignore unit-specific random effects and potential correlation among repeated measurements. This paper presents a nonlinear mixed-effects model enabling accounting for the correlation between observations on the same pavement section. On the basis of this nonlinear mixed-effects modeling, we investigate and identify structural and climatic factors that explain differences in the parameters between pavement sections, and quantify the impact of these factors on pavement evolution. The proposed model provides a good fit for describing the evolution law of different pavement sections. The performance of this model is assessed using simulated and real data.

Bitumen aging has long been recognized as one of the primary factors that affect pavement's durability. The amount of rheology-based indexes proposed to track the evolution of bitumen aging level underlines their potential for this purpose.Among these phase angle is a powerful tool since it is highly sensitive to changes that occur in bitumen. Hence, this work aims to estimate the aging level of 23 neat bitumens based solely on the evaluation of their phase angle master curve through the application of two multivariate statistical approaches: Principal Component Analysis (PCA) and Hierarchical Cluster Analysis (HCA). PCA score plot displays correctly the studied bitumens according to their aging level, going from left to right, where a marked inflection point is detected along the path taken by the studied bitumen when they age. The groups of bitumens located on each side of this inflection point coincide with the two major clusters obtained through HCA. All the bitumens classified as being in the imminent or cracking zone through the well-known Glover Rowe (G-R) cracking indicator integrate the HCA cluster after the inflection point. The originality of this study lies in the possibility of indicating the aging state and also cracking susceptibility of bitumen based exclusively on the assessment of the phase angle master curve.

The development of citizen-based approaches to the diagnosis and decision-making on urban noise environments responds to a demand from both local authorities and residents. However, the methods for fostering the involvement of citizens and the valorization of local knowledge have yet to be invented. This article reports on a co-constructed experiment between researchers and local authorities, in the city of Rezé (France), of an urban noise diagnosis based on the residents and the use of the smartphone application NoiseCapture, which allows a participative measurement of sound levels. The framework also includes focus group discussions. The dynamics of the recruitment and data collection phase are analysed, showing the importance of creating public events around the initiative. Maps of noise levels, but also of the presence of sound sources, such as road, rail and air traffic, or animals, are produced in a collaborative way. Finally, the focus group discussions highlight that (i) repeated noise measurement modifies participants’ relationship to sound environments; (ii) NoiseCapture enhances the formation of a group of residents active on noise issues. Such a framework can provide a citizen-based basis for decisions on noise environments; the next step will be to study its adaptability to different territories.