Use of a smart electrically assisted bicycle (VELIS) in the health field -Proof of concept-

International audiencehysical activity (PA) is highly recommended in the management of most chronic diseases. For these patients, the smart electric bicycle can be effective to improve adherence to this behavior. The E-bike used in this study (called VELIS) has an innovative onboard technology that allows for subject monitoring and the engine power is designed to adapt to the user's abilities. A prerequisite for the use of the VELIS with patients is to initially carry out a pilot study on healthy subjects. The objective was to evaluate the impact of the customizable settings on physiological parameters and to ensure this prototype's efficiency and safety of use. Twelve healthy participants with various profiles (physical condition, used to cycling or not) were included. They have completed four times a 14 km itinerary with various settings of the VELIS. We recorded GPS data, heart rate and perceived exertion. Based on exercise intensity, we confirm that riding an E-bike should be considered as a physical activity. Safety of the participants is ensured by the engine brake. Recordings show that it took between 1 and 3 min for the novice to become familiar with the VELIS and to get optimal assistance. The main finding of this pilot study confirms that VELIS is an easy to use and secure tool to make PA approachable, whatever the level of training in healthy subjects

Probabilistic analysis of rain-triggered lahar initiation at Tungurahua volcano

Semi-continuous production of pyroclastic material by intermittent strombolian, vulcanian and sub-plinian eruptions at Volcán Tungurahua, Ecuador has created a persistent rain-triggered lahar hazard during the 1999-present eruptive episode. Lahars threaten the city of Baños, which lies approximately 8 km from the crater, as well as other villages and vital infrastructure situated in close proximity to the dense radial drainage network of the volcano. This study analyses the initiation of rain-triggered lahars and the influence of antecedent rainfall on this process in two northern instrumented drainages, La Pampa and the Vazcun. Analysis of lahar-triggering rainfall intensity and duration between March 2012 and June 2013 yields a power-law relationship, while Receiver Operating Characteristic (ROC) analysis indicates that peak rainfall intensity (10 minute, 30 minute and 60 minute) is the most effective single predictor of lahar occurrence. The probability of a lahar exceeding a pre-defined magnitude increases with peak rainfall intensity. Incorporation of antecedent rainfall (24 hour, 3 day, 5 day and 7 day) as a secondary variable significantly impacts lahar probabilities, particularly during moderate-high intensity rainfall events. The resultant two and three-dimensional lahar probability matrices are applied to rainfall data between 1st July and 31st December 2013 with the aim of predicting lahar occurrence. Composite lahar indicators comprised from the mean lahar probability estimates of individual matrices are shown to perform this task most effectively. ROC analysis indicates a probability >80% that these composite indicators will generate a higher estimated lahar probability for a randomly selected lahar event than a randomly selected non-lahar event. This method provides an average of 24 minutes of additional warning time compared with the current Acoustic Flow Monitors (AFMs) used for lahar detection, effectively doubling warning times for key downstream infrastructure in the two drainages. Ultimately, this method of lahar analysis could be used to construct real-time probabilistic rain-triggered lahar forecasts as an aid to current lahar hazard mitigation techniques at any location with a significant rain-triggered lahar hazard and a basic instrumental set-up

Transcription regulation by the Mediator complex

International audienceAlterations in the regulation of gene expression are frequently associated with developmental diseases or cancer. Transcription activation is a key phenomenon in the regulation of gene expression. In all eukaryotes, mediator of RNA polymerase II transcription (Mediator), a large complex with modular organization, is generally required for transcription by RNA polymerase II, and it regulates various steps of this process. The main function of Mediator is to transduce signals from the transcription activators bound to enhancer regions to the transcription machinery, which is assembled at promoters as the preinitiation complex (PIC) to control transcription initiation. Recent functional studies of Mediator with the use of structural biology approaches and functional genomics have revealed new insights into Mediator activity and its regulation during transcription initiation, including how Mediator is recruited to transcription regulatory regions and how it interacts and cooperates with PIC components to assist in PIC assembly. Novel roles of Mediator in the control of gene expression have also been revealed by showing its connection to the nuclear pore and linking Mediator to the regulation of gene positioning in the nuclear space. Clear links between Mediator subunits and disease have also encouraged studies to explore targeting of this complex as a potential therapeutic approach in cancer and fungal infections

Depths of magma chambers at three volcanic provinces in the Karlıova region of Eastern Turkey

The size of a volcanic eruption, and thus the associated potential hazards, depends partly on the depth, geometry, and size of the source magma chamber. To estimate magma chamber depths and sizes, we apply a newly developed analytical method, based on the aspect ratio (length/thickness) of dikes, to three volcanoes in the Karlıova region of Eastern Turkey, namely Turnadağ, Varto, and Özenç. The results indicate that the depths of the source chambers are between 2 and 4 km at Turnadağ, 2 to 5 km at Varto, both of which are located in transtensional tectonic regimes, but from 22 to 27 km at Özenç, which is located in a convergent tectonic regime. A similar reservoir depth at Özenç is indicated by seismic tomography, and this data also suggests that the reservoir is laterally continuous for more than 40 km. The large volume of ignimbrites (> 40 km3) associated with Varto, a collapse caldera, indicates that caldera subsidence may have maintained the excess magmatic pressure (through tectonic forcing) in the chamber over a longer time than during normal pyroclastic eruptions. The dike aspect ratios further indicate magmatic overpressures of 13–21 MPa for Varto, 13–17 MPa for Turnadağ, and 26–31 MPa for Özenç. The combined results from seismic tomography, analytical models and magma compositions indicate that both Turnadağ and Varto volcanoes, which are typical stratovolcanoes composed of mostly intermediate, and more rarely, acidic magmas, were fed by two very shallow and comparatively small magma chambers (2–5 km depth). Whereas less evolved magmas were erupted from Özenç, which hosts predominantly basaltic and intermediate lavas and dikes that were fed by a deep reservoir at 22–27 km depth. Our tomographic models show that none of the volcanoes are located directly over the center of a deep magma reservoir. Our data also indicates that the magma in the reservoir has migrated between 34 and 40 km in a right lateral motion (to the east) below Varto and Turnadağ, respectively, and 23 km in a left lateral motion (to the west) at Özenç over the past 3 Ma. This lateral propagation of magma can be explained by tectonic escape of the Anatolian block to the west through the Northern Anatolian Fault and the Varto Fault Zone over the last 6 Ma