Université Nantes Angers Le Mans

About: Université Nantes Angers Le Mans is a education organization based out in Nantes, France. It is known for research contribution in the topics: Geology & Population. The organization has 434 authors who have published 249 publications receiving 7208 citations. The organization is also known as: PRES Universite Nantes Angers Le Mans.

Describing and classifying urban sound environments with a relevant set of physical indicators

Abstract: Categorization is a powerful method for describing urban sound environments. However, it has only been applied, until now, to discrete noise data collection, whereas sound environments vary continuously both in space and time. Therefore, a procedure is developed in this paper for describing the variations of urban sound environments. The procedure consists of mobile measurements, followed by a statistical clustering analysis that selects relevant noise indicators and classifies sound environments. Analysis are based on a 3 days + 1 night survey where geo-referenced noise measurements were collected over 19 1-h soundwalk periods in a district of Marseille, France. The clustering analysis showed that a limited subset of indicators is sufficient to discriminate sound environments. The three indicators that emerged from the clustering, namely, the Leq,A, the standard deviation σLeq,A, and the sound gravity spectrum SGC[50 Hz–10 kHz], are consistent with previous studies on sound environment classification. Mo...

Influence of the kenaf fiber length on the mechanical and thermal properties of Compressed Earth Blocks (CEB)

Abstract: The association of natural fibers and raw land soil has many advantages (thermal control, sound insulation, mechanical behavior, etc.). However, the major issue with the use of these materials is the lack of knowledge regarding their reliability and durability. In this work, we have evaluated the influence of kenaf fiber length on the mechanical and thermal properties of compressed earth blocks (CEB). Fibers with length 10, 20 or 30 mm were used at mixing rate of 1.2% dry weight of soil; with the aim to enhance the mechanical and thermal properties of CEB fabricated starting from a plastic clayey soil mined in Benin. Analysis of the mechanical behavior of different Soil/Fiber formulations in terms of flexural strength demonstrated the beneficial effect of the fibers. However, the mechanical strength of CEB obtained by immersing fibers till saturation prior to incorporation into the soil greatly diminished. The higher flexural strength was obtained with fibers 30 mm long. The thermal conductivity of CEB decreased when the fiber length was raised. The results showed the real possibility to improve CEB mechanical and thermal properties by using fibers for reinforcement.

Progressive ataxia of Charolais cattle highlights a role of KIF1C in sustainable myelination

Abstract: Hereditary spastic paraplegias (HSPs) are clinically and genetically heterogeneous human neurodegenerative diseases. Amongst the identified genetic causes, mutations in genes encoding motor proteins such as kinesins have been involved in various HSP clinical isoforms. Mutations in KIF1C are responsible for autosomal recessive spastic paraplegia type 58 (SPG58) and spastic ataxia 2 (SPAX2). Bovines also develop neurodegenerative diseases, some of them having a genetic aetiology. Bovine progressive ataxia was first described in the Charolais breed in the early 1970s in England and further cases in this breed were subsequently reported worldwide. We can now report that progressive ataxia of Charolais cattle results from a homozygous single nucleotide polymorphism in the coding region of the KIF1C gene. In this study, we show that the mutation at the heterozygous state is associated with a better score for muscular development, explaining its balancing selection for several decades, and the resulting high frequency (13%) of the allele in the French Charolais breed. We demonstrate that the KIF1C bovine mutation leads to a functional knock-out, therefore mimicking mutations in humans affected by SPG58/SPAX2. The functional consequences of KIF1C loss of function in cattle were also histologically reevaluated. We showed by an immunochemistry approach that demyelinating plaques were due to altered oligodendrocyte membrane protrusion, and we highlight an abnormal accumulation of actin in the core of demyelinating plaques, which is normally concentrated at the leading edge of oligodendrocytes during axon wrapping. We also observed that the lesions were associated with abnormal extension of paranodal sections. Moreover, this model highlights the role of KIF1C protein in preserving the structural integrity and function of myelin, since the clinical signs and lesions arise in young-adult Charolais cattle. Finally, this model provides useful information for SPG58/SPAX2 disease and other demyelinating lesions.

Gas chromatography coupled to mass spectrometry-based metabolomic to screen for anabolic practices in cattle: identification of 5α-androst-2-en-17-one as new biomarker of 4-androstenedione misuse

Abstract: The use of anabolic steroids as growth promoters for meat-producing animals is banned within the European Union However, screening for the illegal use of natural steroid hormones still represents a difficult challenge because of the high interindividual and physiological variability of the endogenous concentration levels in animals In this context, the development of untargeted profiling approaches for identifying new relevant biomarkers of exposure and/or effect has been emerging for a couple of years The present study deals with an untargeted metabolomics approach on the basis of GC-MS aiming to reveal potential biomarkers signing a fraudulent administration of 4-androstenedione (AED), an anabolic androgenic steroid chosen as template After a sample preparation based on microextraction by packed sorbent, urinary profiles of the free and deglucurono-conjugates urinary metabolites were acquired by GC-MS in the full-scan acquisition mode Data processing and chemometric procedures highlighted 125 ions, allowing discrimination between samples collected before and after an administration of 4-AED After a first evaluation of the signal robustness using additional and independent non-compliant samples, 17 steroid-like metabolites were pointed out as relevant candidate biomarkers All these metabolites were then monitored using a targeted GC-MS/MS method for an additional assessment of their capacity to be used as biomarkers Finally, two steroids, namely 5α-androstane-3β,17α-diol and 5α-androst-2-en-17-one, were concluded to be compatible with such a definition and which could be finally usable for screening purpose of AED abuse in cattle

Ranavirus causes mass die-offs of alpine amphibians in the southwestern alps, france

Abstract: Pathogenic fungi and viruses cause mortality outbreaks in wild amphibians worldwide. In the summer of 2012, dead tadpoles and adults of the European common frog Rana temporaria were reported in alpine lakes in the southwestern Alps (Mercantour National Park, France). A preliminary investigation using molecular diagnostic techniques identified a Ranavirus as the potential pathogenic agent. Three mortality events were recorded in the park, and samples were collected. The amphibian chytrid fungus Batrachochytrium dendrobatidis was not detected in any of the dead adult and juvenile frogs sampled (n=16) whereas all specimens were positive for a Ranavirus. The genome sequence of this Ranavirus was identical to previously published sequences of the common midwife toad virus (CMTV), a Ranavirus that has been associated with amphibian mortalities throughout Europe. We cultured virus from the organs of the dead common frogs and infecting adult male common frogs collected in another alpine region where no frog mortality had been observed. The experimentally infected frogs suffered 100% mortality (n=10). The alpine die-off is the first CMTV outbreak associated with mass mortality in wild amphibians in France. We describe the lesions observed and summarize amphibian populations affected by Ranaviruses in Europe. In addition, we discuss the ecologic specificities of mountain amphibians that may contribute to increasing their risk of exposure to and transmission of Ranaviruses.