CM-fields and skew-symmetric matrices

Abstract.: Cohen and Odoni prove that every CM-field can be generated by an eigenvalue of some skew-symmetric matrix with rational coefficients. It is natural to ask for the minimal dimension of such a matrix. They show that every CM-field of degree 2n is generated by an eigenvalue of a skew-symmetric matrix over Q of dimension at most 4n+2. The aim of the present paper is to improve this boun

L’enseignement de l’histoire de France en Français Langue étrangère

This article examines the proposition that general culture and particularly French history are precious tools for learning French as a Foreign Language (FFL). Developing various linguistic aptitudes, debating current events, gaining in-depth understanding of the society underpinning the target language, are only some aspects of this overall enhancement. We also address the didactics of FFL to see which concepts can assist teachers in integrating the discipline in the classroom and using authentic documents with their students, particularly thanks to the new technologies (TIC).Quest’articolo si propone di vedere in che cosa la cultura colta e più particolarmente la Storia di Francia siano preziose in una lezione di lingue. Sviluppo di diverse competenze linguistiche, dibattiti civici, comprensione approfondita della società della lingua target sono solo alcuni aspetti di quest’arricchimento globale. Si tratterà di studiare anche quali concetti di didattica del francese come lingua straniera possano aiutarci a integrare questa disciplina in classe e a sfruttare abilmente documenti autentici con gli studenti, in particolare grazie all’aiuto dei programmi informatici legati all’insegnamento

The effect of load distribution within military load carriage systems on the kinetics of human gait

Military personnel carry their equipment in load carriage systems (LCS) which consists of webbing and a Bergen (aka backpack). In scientific terms it is most efficient to carry load as close to the body's centre of mass (CoM) as possible, this has been shown extensively with physiological studies. However, less is known regarding the kinetic effects of load distribution. Twelve experienced load carriers carried four different loads (8, 16, 24 and 32 kg) in three LCS (backpack, standard and AirMesh). The three LCS represented a gradual shift to a more even load distribution around the CoM. Results from the study suggest that shifting the CoM posteriorly by carrying load solely in a backpack significantly reduced the force produced at toe-off, whilst also decreasing stance time at the heavier loads. Conversely, distributing load evenly on the trunk significantly decreased the maximum braking force by 10%. No other interactions between LCS and kinetic parameters were observed. Despite this important findings were established, in particular the effect of heavy load carriage on maximum braking force. Although the total load carried is the major cause of changes to gait patterns, the scientific testing of, and development of, future LCS can modify these risks

Muscle inactivation of mTOR causes metabolic and dystrophin defects leading to severe myopathy

Mammalian target of rapamycin (mTOR) is a key regulator of cell growth that associates with raptor and rictor to form the mTOR complex 1 (mTORC1) and mTORC2, respectively. Raptor is required for oxidative muscle integrity, whereas rictor is dispensable. In this study, we show that muscle-specific inactivation of mTOR leads to severe myopathy, resulting in premature death. mTOR-deficient muscles display metabolic changes similar to those observed in muscles lacking raptor, including impaired oxidative metabolism, altered mitochondrial regulation, and glycogen accumulation associated with protein kinase B/Akt hyperactivation. In addition, mTOR-deficient muscles exhibit increased basal glucose uptake, whereas whole body glucose homeostasis is essentially maintained. Importantly, loss of mTOR exacerbates the myopathic features in both slow oxidative and fast glycolytic muscles. Moreover, mTOR but not raptor and rictor deficiency leads to reduced muscle dystrophin content. We provide evidence that mTOR controls dystrophin transcription in a cell-autonomous, rapamycin-resistant, and kinase-independent manner. Collectively, our results demonstrate that mTOR acts mainly via mTORC1, whereas regulation of dystrophin is raptor and rictor independent

Muscle molecular adaptations to endurance exercise training are conditioned by glycogen availability: a proteomics-based analysis in the McArdle mouse model

KEY POINTS: Although they are unable to utilize muscle glycogen, McArdle mice adapt favourably to an individualized moderate-intensity endurance exercise training regime. Yet, they fail to reach the performance capacity of healthy mice with normal glycogen availability. There is a remarkable difference in the protein networks involved in muscle tissue adaptations to endurance exercise training in mice with and without glycogen availability. Indeed, endurance exercise training promoted the expression of only three proteins common to both McArdle and wild-type mice: LIMCH1, PARP1 and TIGD4. In turn, trained McArdle mice presented strong expression of mitogen-activated protein kinase 12 (MAPK12). ABSTRACT: McArdle's disease is an inborn disorder of skeletal muscle glycogen metabolism that results in blockade of glycogen breakdown due to mutations in the myophosphorylase gene. We recently developed a mouse model carrying the homozygous p.R50X common human mutation (McArdle mouse), facilitating the study of how glycogen availability affects muscle molecular adaptations to endurance exercise training. Using quantitative differential analysis by liquid chromatography with tandem mass spectrometry, we analysed the quadriceps muscle proteome of 16-week-old McArdle (n = 5) and wild-type (WT) (n = 4) mice previously subjected to 8 weeks' moderate-intensity treadmill training or to an equivalent control (no training) period. Protein networks enriched within the differentially expressed proteins with training in WT and McArdle mice were assessed by hypergeometric enrichment analysis. Whereas endurance exercise training improved the estimated maximal aerobic capacity of both WT and McArdle mice as compared with controls, it was ∼50% lower than normal in McArdle mice before and after training. We found a remarkable difference in the protein networks involved in muscle tissue adaptations induced by endurance exercise training with and without glycogen availability, and training induced the expression of only three proteins common to McArdle and WT mice: LIM and calponin homology domains-containing protein 1 (LIMCH1), poly (ADP-ribose) polymerase 1 (PARP1 - although the training effect was more marked in McArdle mice), and tigger transposable element derived 4 (TIGD4). Trained McArdle mice presented strong expression of mitogen-activated protein kinase 12 (MAPK12). Through an in-depth proteomic analysis, we provide mechanistic insight into how glycogen availability affects muscle protein signalling adaptations to endurance exercise training.The CNIC is supported by the Ministry of Economy, Industry and Competitiveness (MEIC) and the Pro CNIC Foundation, and is a Severo Ochoa Centre of Excellence (SEV-2015-0505). This study was funded by grants from Fondo de Investigaciones Sanitarias (PI15/01756, PI15/00558, PI12/00914, and PI14/00903), cofinanced by FEDER. G.N.G. is supported by a Miguel Servet research contract (ISCIII CD14/00032 and FEDER) and C.F.L. by a Sara Borrell post doc contract (CD14/00005). Miguel A. Mart´ın is supported by Fondo de Investigaciones Sanitarias (FIS 15/00432). Tomˆas Pin ´os is supported by Fondo de Investigaciones Sanitarias (FIS PI16/01492).S

Muscle inactivation of mTOR causes metabolic and dystrophin defects leading to severe myopathy

mTor, acting mainly via mTORC1, controls dystrophin transcription in a raptor- and rictor-independent mechanism