Willingness to reduce travel consumption to support a low-carbon transition beyond COVID-19

This paper explores people's willingness to reduce travel consumption in support of the transition to a low-carbon pathway beyond COVID-19, using new survey data from UK car drivers and air travellers. Evidence from our study indicates that reductions of 24% - 30% to car use and 20% - 26% to air travel could be sustained in the long term. This potentially could lead to annual reductions of 343–529 kgCO2 per car driver (20% - 29% of pre- COVID-19 car emissions) and 215–359 kgCO2 per air traveller (10% - 20% of pre-COVID-19 emissions from flying), suggesting that behavioural change may be a major route to emissions reductions. We find that stated voluntary reductions are greater among those who report having ‘more time to do creative things’ since the start of the COVID-19 lockdowns. Hence, recovery policies promoting low-carbon leisure time may be a key to consumption reductions. We also find that higher-income travellers consume and pollute substantially more than the rest, and yet there is little difference in relative voluntary reductions across the income distribution. We conclude that behaviour associated with affluence represents a major barrier to a low-carbon transition, and that policies must address over-consumption associated with affluence as a priority

Modeling T Tauri Winds from He I 10830 Profiles

The high opacity of He I 10830 makes it an exceptionally sensitive probe of the inner wind geometry of accreting T Tauri stars. In this line blueshifted absorption below the continuum results from simple scattering of stellar photons, a situation which is readily modeled without definite knowledge of the physical conditions and recourse to multi-level radiative transfer. We present theoretical line profiles for scattering in two possible wind geometries, a disk wind and a wind emerging radially from the star, and compare them to observed He I 10830 profiles from a survey of classical T Tauri stars. The comparison indicates that subcontinuum blueshifted absorption is characteristic of disk winds in ~30% of the stars and of stellar winds in ~40%. We further conclude that for many stars the emission profile of helium likely arises in stellar winds, increasing the fraction of accreting stars inferred to have accretion-powered stellar winds to ~60%. Stars with the highest disk accretion rates are more likely to have stellar wind than disk wind signatures and less likely to have redshifted absorption from magnetospheric funnel flows. This suggests the possibility that when accretion rates are high, disks can extend closer to the star, magnetospheric accretion zones can be reduced in size and conditions arise that favor radially outflowing stellar winds.Comment: 41 pages, 11 figures. Accepted by Astrophysical Journa

A comparison and a combination of SST and AGM algorithms for counting points of elliptic curves in characteristic 2

International audienceSince the first use of a p-adic method for counting points of elliptic curves, by Satoh in 1999, several variants of his algorithm have been proposed. In the current state, the AGM algorithm, proposed by Mestre is thought to be the fastest in practice, and the algorithm by Satoh­-Skjernaa­-Taguchi has the best asymptotic complexity but requires precomputations. We present an amelioration of the SST algorithm, borrowing ideas from the AGM. We make a precise comparison between this modified SST algorithm and the AGM, thus demonstrating that the former is faster by a significant factor, even for small cryptographic sizes

Historical energy price shocks and their changing effects on the economy

The purpose of this paper is to identify the changes in the impact of energy shocks on economic activity with an interest in assessing if an economy's vulnerability and resilience to shocks improved with economic development. Using data on the United Kingdom over the last three hundred years, the paper identifies supply, aggregate demand and residual shocks to energy prices and estimates their changing influence on energy prices and GDP. The results suggest that the impacts of supply shocks rose with its increasing dependence on coal, and declined with its partial transition to oil. However, the transition from exporting coal to importing oil increased the negative impacts of demand shocks. More generally, the results indicate that improvements in vulnerability and resilience to shocks did not progress systematically as the economy developed. Instead, the changes in impacts depended greatly on the circumstances related to the demand for and supply of energy sources. If these experiences are transferable to future markets, a transition to a diversified mix of renewable energy is likely to reduce vulnerability and increase resilience to energy price shocks. (c) 2017 The Author

Equivalent block transmissivity in an irregular 2D polygonal grid for one-phase flow: a sensitivity analysis

International audienceUpscaling is needed to transform the representation of non additive space-dependent variables, such as permeability, from the fine grid of geostatistical simulations (to simulate small scale spatial variability) to the coarser, generally irregular grids for hydrodynamic transport codes. A new renormalisation method is proposed, based on the geometric properties of a Voronoï grid. It is compared to other classic methods by a sensitivity analysis (grid, range and sill of the variogram, random realisation of a simulation); the criterion is the flux of a tracer at the outlet. The effect of the upscaling technique on the results appears to be of second order compared to the spatial discretisation, the choice of variogram, and the realisation

Serial order of conditional stimuli as a discriminative cue for Pavlovian conditioning

The serial order in which events occur can be a signal for different outcomes and therefore might be a determinant of how an animal should respond. In this report, we propose a novel design for studying serial order learning in Pavlovian conditioning. In both Experiments 1a and 1b, hungry rats were trained with successively presented pairs of auditory and visual stimuli (e.g., A --> B) using four different stimuli (A-D). Four orders were paired with food (A --> B, B --> C, C --> D, D --> A) while the reversals were extinguished (B --> A, C --> B, D --> C, A --> D). An analysis of responding from the second element of each pair showed that the rats discriminated trial types that preceded food from those that did not. A replication of the effect using a completely counterbalanced design is described in Experiment 1b. These results suggest that rats can use the serial or temporal order of two sequentially presented non-overlapping elements as the basis for discrimination. Two associative accounts are suggested as possible mechanisms for solving the discrimination

Computing Hilbert Class Polynomials

We present and analyze two algorithms for computing the Hilbert class polynomial $H_D$ . The first is a p-adic lifting algorithm for inert primes p in the order of discriminant D < 0. The second is an improved Chinese remainder algorithm which uses the class group action on CM-curves over finite fields. Our run time analysis gives tighter bounds for the complexity of all known algorithms for computing $H_D$, and we show that all methods have comparable run times

Forms of work organization and associations with shoulder disorders: Results from a French working population

The aim of this study was to identify forms of work organization in a French region and to study associations with the occurrence of symptomatic and clinically diagnosed shoulder disorders in workers. Workers were randomly included in this cross-sectional study from 2002 to 2005. Sixteen organizational variables were assessed by a self-administered questionnaire: i.e. shift work, job rotation, repetitiveness of tasks, paced work/automatic rate, work pace dependent on quantified targets, permanent controls or surveillance, colleagues\u27 work and customer demand, and eight variables measuring decision latitude. Five forms of work organization were identified using hierarchical cluster analysis (HCA) of variables and HCA of workers: low decision latitude with pace constraints, medium decision latitude with pace constraints, low decision latitude with low pace constraints, high decision latitude with pace constraints and high decision latitude with low pace constraints. There were significant associations between forms of work organization and symptomatic and clinically-diagnosed shoulder disorders