Central morphisms and Cuspidal automorphic Representations

Let $F$ be a global field. Let $G$ and $H$ be two connected reductive group defined over $F$ endowed with an $F$-morphism $f: H\rightarrow G$ such that the induced morphism $H_{der}\rightarrow G_{der}$ on the derived groups is a central isogeny. Our main results yield in particular the following theorem: Given any irreducible cuspidal representation $\pi$ of $G(\mathbb A_F)$ its restriction to $H(\mathbb A_F)$ contains a cuspidal representation $\sigma$ of $H(\mathbb A_F)$. Conversely, assuming moreover that $f$ is an injection, any irreducible cuspidal representation $\sigma$ of $H(\mathbb A_F)$ appears in the restriction of some cuspidal representation $\pi$ of $G(\mathbb A_F)$. This theorem has an obvious local analogue

Dynamic calibration of an instrumented bike brake hood in measuring power absorbed by the hands

AbstractOne of the most significant factors in ride quality in cycling sports are the vibrations generated by road surface defects passing through the bicycle and transmitted to the cyclist's hands and buttocks. To study comfort, one metric that has been put forward is the measurement of the power absorbed at the cyclist's hands. Measuring absorbed power requires the use of the force and the velocity at the hands and provides an overall energy-based quantity. The aim of this study is to dynamically calibrate an instrumented brake hood transducer to measure the power absorbed at the cyclist's hands. Using a base excitation technique involving suspended masses, dynamic calibration of the brake hood was conducted in the 3-100 Hz frequency range, and the force transducer sensitivity and seismic mass were measured. An accelerometer attached to the brake hood enabled measurements of acceleration and calculation of velocity. A frequency-dependent phase mismatch between the force signal and the acceleration was obtained by measuring the accelerance at the hand-bike interface. A device called the Power Calibrator equipped with an impedance head was developed to assess the accuracy of the power measured by the instrumented brake hood. The results show that the instrumented brake hood can accurately measure the absorbed power at the cyclist's hands. Phase mismatch between the force and the velocity signals must be corrected to improve the accuracy of measurements. To implement the measurements, it is recommended that the calculations be done in the frequency domain

The centrality dependence of elliptic flow, the hydrodynamic limit, and the viscosity of hot QCD

We show that the centrality and system-size dependence of elliptic flow measured at RHIC are fully described by a simple model based on eccentricity scaling and incomplete thermalization. We argue that the elliptic flow is at least 25% below the (ideal) ``hydrodynamic limit'', even for the most central Au-Au collisions. This lack of perfect equilibration allows for estimates of the effective parton cross section in the Quark-Gluon Plasma and of its viscosity to entropy density ratio. We also show how the initial conditions affect the transport coefficients and thermodynamic quantities extracted from the data, in particular the viscosity and the speed of sound.Comment: 5 pages, 2 figures. Extended discussion of the results, in particular of lower viscosity and sound velocity required by CGC initial condition

The impact of compaction, moisture content, particle size and type of bulking agent on initial physical properties of sludge-bulking agent mixtures before composting

This study aimed to experimentally acquire evolution profiles between depth, bulk density, Free Air Space (FAS), air permeability and thermal conductivity in initial composting materials. The impact of two different moisture content, two particle size and two types of bulking agent on these four parameters was also evaluated. Bulk density and thermal conductivity both increased with depth while FAS and air permeability both decreased with it. Moreover, depth and moisture content had a significant impact on almost all the four physical parameters contrary to particle size and the type of bulking agent

Testing biological hypotheses in site occupancy models: a Bayesian approach

The occupancy rate of a target species in a region divided in quadrats (or sites) is defined as the proportion of quadrats occupied by this species. This is a key quantity in site occupancy models which typically remains unknown after the data are collected, because the probability of detecting a target species in a given quadrat is < 1. Implementing tests on occupancy rates leads to a quite unusual situation, because an occupancy rate is not a statistical parameter, but a function of a discrete process partially observed. To deal with that difficulty, we adopt a Bayesian view within which the treatment of such tests turns out to be natural. We develop our approach for discrete-time site occupancy data, and we illustrate it by testing if the occupancy rate of a bird species increases over time (colonization test). A Bayesian model averaging is implemented to deal with the fact that several plausible models are viewed for the data at hand. We state a closed-form expression for the posterior probability of each model. The posterior probability of the null hypothesis (under a given model) is obtained by implementing a data augmentation algorithm. Finally, from a variety of examples, we show that the Bayesian methodology allows us to address a wide range of questions about occupancy

A long-term copper exposure on freshwater ecosystem using lotic mesocosms: Individual and population responses of three-spined sticklebacks (Gasterosteus aculeatus)

Three-spined stickleback (Gasterosteus aculeatus) was used as the highest trophic level predator in an outdoor mesocosm study assessing the effect of environmentally realistic copper concentration (0, 5, 25 and 75 μg L−1) over 18 months of continuous exposure. Condition factor, organosomatic indices (HIS, GSI and SSI) as well as copper bioaccumulation in the liver were measured at 15 days, 2, 4, 6, 10, 14 and 18 months after the beginning of the contamination. Population monitoring was realised after 6 and 18 months of contamination, allowing two reproduction periods to be measured. Results showed that condition factor was affected at medium and high copper concentrations and HSI was sporadically affected in all copper exposure, depending on the sex of the fish. GSI did not show any significant differences and SSI was lowered in the medium and high copper levels. Bioaccumulation was significantly different in males and females and fluctuated with season. A negative correlation was observed between copper bioaccumulation in the liver and fish size and a positive correlation with nominal copper concentration in the water was found. There was a negative correlation between condition factor, organosomatic indices and bioaccumulation in the liver. Population monitoring showed a significantly higher fish mean length after 6 months and a higher abundance after 18 months of exposure at the highest copper level. We conclude that indirect effects such as food and habitat availability or lower predation pressure on eggs and juveniles might have led to higher stickleback population abundances at the highest copper level. This highlights the need to study all the trophic levels when monitoring ecosystem health. Considering the population and the individual responses after 18 months of copper exposure, the NOEC for three-spined sticklebacks was 25 μg L−1 (or 20 μg L−1 if we consider the average effective concentration), with a LOEC of 75 μg L−1 (or 57 μg L−1, AEC)