Advances in characterization of the soil clay mineralogy using X-ray diffraction: from decomposition to profile fitting

International audienceStructural characterization of soil clay minerals often remains limited despite their key influence on soil properties. In soils, complex clay parageneses result from the coexistence of clay species with contrasting particle sizes and crystal-chemistry and from the profusion of mixed layers with variable compositions. The present study aimed at characterizing the mineralogy and crystal chemistry of the < 2 μm fraction along a profile typical of soils from Western Europe and North America (Neo Luvisol). X-ray diffraction (XRD) patterns were nterpreted using i) the combination of XRD pattern decomposition and indirect identification from peak positions commonly applied in soil science and ii) the multi-specimen method. This latter approach implies direct XRD profile fitting and has recently led to significant improvements in the structural characterization of clay minerals in diagenetic and hydrothermal environments. In contrast to the usual approach, the multi-specimen method allowed the complete structural characterization of complex clay parageneses encountered in soils together with the quantitative analysis of their mineralogy. Throughout the profile, the clay paragenesis of the studied Neo Luvisol systematically includes discrete smectite, illite and kaolinite in addition to randomly interstratified illite-smectite and chlorite-smectite. Structural characteristics of the different clay minerals, including the composition of mixed layers, did not vary significantly with depth and are thus indicative of the parent material. The relative proportion of the < 2 μm fraction increased with increasing depth simultaneously with smectite relative proportion. These results are consistent with the leaching process described for Luvisols in the literature

Real-Time Locating System to study the persistence of sociality in large-mammal group dynamics

Je n'ai pas encore les pages des proceedingsReal-Time Locating System to study the persistence of sociality in large-mammal group dynamics. European Conference on Precisions Livestock Farming (ECPLF

Illite-smectite mixed-layer minerals in hydrothermal alteration of volcanic rocks: I. One-dimensional XRD structure analysis and characterisation of component layers.

International audienceFor a series of mixed-layer illite-smectite (I-S) minerals from a drill hole near the Kakkonda geothermal field, one-dimensional structure analysis by X-ray diffraction (XRD) was performed using Ca-saturated specimens at both air-dried and ethylene glycol solvated states. The expandability characteristics of component layers were also examined by means of alkylammonium exchange and Li-saturation. The K content in illite layer was almost constant at 1.5-1.7/O20(OH)4 in the I-S series from 3% to 85% of I-layer content (% I). The layer charge of smectite layer varied slightly within the ranges of R1 I-S samples showed complicated expandability with alkylammonium exchange. The XRD patterns of dodecylammonium exchanged I-S samples can be interpreted by random interstratification of several types of sub-units such as layer-doublets, layer-triplets and layer-quarutets present in the crystallites. This interpretation is consistent with the variation in the occurrence probabilities of layer-multiplets calculated from the junction probabilities and the proportions of layers. Because the interpretation indicates that I-S is a stack of various types of the sub-units, the smectite illitization can be described by a systematic change in the type and proportion of the sub-units constituting crystallites

Newsletter N°2-DACEFI

Développement d'Alternatives Communautaires à la Foresterie IllégaleVersion allégé

Molecular profiles of Quadriceps muscle in myostatin-null mice reveal PI3K and apoptotic pathways as myostatin targets

<p>Abstract</p> <p>Background</p> <p>Myostatin (MSTN), a member of the TGF-β superfamily, has been identified as a negative regulator of skeletal muscle mass. Inactivating mutations in the MSTN gene are responsible for the development of a hypermuscular phenotype. In this study, we performed transcriptomic and proteomic analyses to detect altered expression/abundance of genes and proteins. These differentially expressed genes and proteins may represent new molecular targets of MSTN and could be involved in the regulation of skeletal muscle mass.</p> <p>Results</p> <p>Transcriptomic analysis of the Quadriceps muscles of 5-week-old <it>MSTN</it>-null mice (n = 4) and their controls (n = 4) was carried out using microarray (human and murine oligonucleotide sequences) of 6,473 genes expressed in muscle. Proteomic profiles were analysed using two-dimensional gel electrophoresis coupled with mass spectrometry. Comparison of the transcriptomic profiles revealed 192 up- and 245 down- regulated genes. Genes involved in the PI3K pathway, insulin/IGF pathway, carbohydrate metabolism and apoptosis regulation were up-regulated. Genes belonging to canonical Wnt, calcium signalling pathways and cytokine-receptor cytokine interaction were down-regulated. Comparison of the protein profiles revealed 20 up- and 18 down-regulated proteins spots. Knockout of the MSTN gene was associated with up-regulation of proteins involved in glycolytic shift of the muscles and down-regulation of proteins involved in oxidative energy metabolism. In addition, an increased abundance of survival/anti-apoptotic factors were observed.</p> <p>Conclusion</p> <p>All together, these results showed a differential expression of genes and proteins related to the muscle energy metabolism and cell survival/anti-apoptotic pathway (e.g. DJ-1, PINK1, 14-3-3ε protein, TCTP/GSK-3β). They revealed the PI3K and apoptotic pathways as MSTN targets and are in favour of a role of MSTN as a modulator of cell survival in vivo.</p

Promotion of an active and healthy lifesyle at school: The French speaking belgium case

En Fédération Wallonie-Bruxelles (Belgique francophone), dès 2008, alors que les finalités du cours d’éducation physique (EP) étaient centrées sur la santé, la condition physique, l’expression et la culture motrice et sportive, Cloes mettait en évidence l’importance que les enseignants en éducation physique devaient accorder à l’un des objectifs généraux de l’Ecole : préparer les jeunes à devenir des citoyens responsables … de leur corps tout au long de leur vie. Actuellement, une vaste réforme est mise en œuvre : le Pacte pour un Enseignement d’Excellence (FWB, 2017). Elle identifie l’activité physique, le bien-être et la santé comme l’un des sept domaines d’apprentissage prioritaires. Parallèlement aux démarches des autorités publiques visant à proposer des outils aux acteurs de terrain, de nombreuses initiatives sont mises en place par ceux-ci. Cet exposé porte sur l’identification des caractéristiques d’actions proposées par des écoles primaires dans la perspective de promouvoir l’activité physique. Cette présentation s’inscrit dans le modèle heuristique du processus enseignement-apprentissage (Cloes & Roy, 2010). 210 écoles primaires ont été sollicitées dans le cadre d’un appel à projets lancé en 2018 par le Service Culture et Sport de la Province de Luxembourg ; 16 ont répondu et les dossiers de 13 d’entre elles ont été retenus. Ces derniers ont fait l’objet d’une analyse multidimensionnelle. Dans la perspective de promouvoir les initiatives des écoles en matière de promotion de l’activité physique, il convient de stimuler l’intérêt des équipes pédagogiques et d’attirer leur attention sur la diversité des actions à mettre en œuvre

Understanding PE teachers’ opinions about physical fitness assessment in children aged 10-11 years

Introduction: Physical fitness assessments for children, aged 10-11 years were performed in the province of Luxembourg. Children went to sports centres with their teachers to achieve a battery of 8 tests, evaluating different parameters of their physical fitness. However, this assessment campaign was restricted to the evaluation physical fitness and was focused on performances. Moreover, PE teacher’s involvement in this campaign seemed limited. From October 2023, the framework of the campaign will be modified following recommendations of the new curriculum for health and physical education. Objectives: The aim of this study was to collect PE teachers' opinions about the objectives of the campaign, their role and how the campaign fitted into their PE lessons. Methods: Interviews were conducted to meet forty-five PE teachers involved in the 2022-campaign. Discussions were recorded. Ideas discussed in each interview were transcribed. This procedure was used to create an online survey. Results: Thirty-seven PE teachers completed the online survey. Very few PE teachers were involved in projects regarding the new curriculum. Ninety-two percent of PE teachers prepared their students for the tests. Ninety-two percent of PE teachers informed their students about their results. Results were not discussed with parents. Three-quarters of PE teachers wanted to further integrate the campaign. Conclusion: This survey analysed the impact of this campaign on teachers' interventions, as well as the barriers encountered. This study could allow a better collaboration between PE teachers, parents, researchers, and members of the sports service for the development of future campaigns

The fitness barometer, a tool for physical education teachers

Introduction: Belgium has been working on physical fitness assessment since a couple of years (1994, 2004, 2013). In the Province of Luxembourg, a physical fitness campaign was organised every year for children in grades 5 and 6 (10-11 years). In October 2023 this campaign will be modified to provide motor and physical assessment, and health promotion. Several fitness tests will be removed. Objectives: The aim of this study was to provide a complete fitness barometer with the results of the campaign 2022. Methods: In 2022, 4,344 children aged 10 and 11 years performed 8 fitness tests, assessing upper and lower limbs explosive power, cardio-respiratory endurance, speed, flexibility, and abdominal endurance. Tests were assessed by external assessors. Data were analysed by researchers. R software (Rcmdr) was used for statistical analysis. Four groups were categorized by gender and age. Descriptive statistical analysis of percentiles was conducted for each group. Results: Percentiles divided statistical series into different categories that allowed each child to be placed in relation to usual values of children of his/her province, age, and gender. Results for each child highlight some qualities and weaknesses of his/her physical fitness, at the assessment time. Conclusion: This barometer delivered to PE teachers an individualized profile for each student. Collective results were provided for the PE teacher showing strengths and weaknesses of their class. Physical fitness is one domain of competencies that a person must develop to be physically active. Other domains of competencies should be added to this campaign