Metrology and 1/f noise: linear regressions and confidence intervals in flicker noise context

1/f noise is very common but is difficult to handle in a metrological way. After having recalled the main characteristics of stongly correlated noise, this paper will determine relationships giving confidence intervals over the arithmetic mean and the linear drift parameters. A complete example of processing of an actual measurement sequence affected by 1/f noise will be given

THE IMPACT OF CONSERVATION TILLAGE ON THE PRODUCTIVITY AND STABILITY OF MAIZE CROPPING SYSTEMS: A CASE STUDY IN WESTERN MEXICO

This paper examines the economics of introducing conservation tillage into maize cropping systems in the state of Jalisco, in the western part of Mexico. A stochastic cost-benefit analysis (SCBA) of introducing conservation tillage in two contrasting agro-climatic zones in the four main maize management systems in the area was carried out. The SCBA takes into account the effects of conservation tillage on average returns and fully evaluates its potential risk-reducing aspect. The SCBA results were then used for a stochastic dominance analysis to evaluate farmers' incentives, characterized by their aversion to risk. The analysis reveals that although conservation tillage is economically viable, cash-constrained farmers, especially in the dry areas, may not readily adopt it. This is because conservation tillage is not adapted to small-scale farmers in Mexico, who lack seeding equipment and need techniques that are less reliant on herbicides. It is suggested that more work should be done with the participation of farmers in the region to attain a conservation tillage system that is better adapted to their circumstances.Mexico, Jalisco, Plant production, Production factors, Cropping systems, Conservation tillage, Innovation adoption, Input output analysis, Economic analysis, Small farms, Productivity Analysis,

An Evaluation of “Special Educational Needs” Programmes in England

The need for education to help every child rather than focus on average attainment has become a more central part of the policy agenda in the US and the UK. Remedial programmes are often difficult to evaluate because participation is usually based on pupil characteristics that are largely unobservable to the analyst. In this paper we evaluate programmes for children with moderate levels of 'special educational needs' in England. We show that the decentralized design of the policy generates significant variations in access to remediation resources across children with similar prior levels of difficulty. However, this differential is not reflected in subsequent educational attainment - suggesting that the programme is ineffective for 'treated' children. In the second part of our analysis, we use demographic variation within schools to consider the effect of the programme on whole year groups. Our analysis is consistent with no overall effect on account of the combined direct and indirect (spillover) effects. Thus, the analysis suggests that a key way that English education purports to help children with learning difficulties is not working.education, special needs, evaluation,

Every Child Matters? An Evaluation of "Special Educational Needs" Programmes in England

The need for education to help every child rather than focus on average attainment has become a more central part of the policy agenda in the US and the UK. Remedial programmes are often difficult to evaluate because participation is usually based on pupil characteristics that are largely unobservable to the analyst. In this paper we evaluate programmes for children with moderate levels of 'special educational needs' in England. We show that the decentralized design of the policy generates significant variations in access to remediation resources across children with similar prior levels of difficulty. However, this differential is not reflected in subsequent educational attainment – suggesting that the programme is ineffective for 'treated' children. In the second part of our analysis, we use demographic variation within schools to consider the effect of the programme on whole year groups. Our analysis is consistent with no overall effect on account of the combined direct and indirect (spillover) effects. Thus, the analysis suggests that a key way that English education purports to help children with learning difficulties is not working.education, special needs, evaluation

Fast algorithms for computing isogenies between elliptic curves

We survey algorithms for computing isogenies between elliptic curves defined over a field of characteristic either 0 or a large prime. We introduce a new algorithm that computes an isogeny of degree $\ell$ ($\ell$ different from the characteristic) in time quasi-linear with respect to $\ell$. This is based in particular on fast algorithms for power series expansion of the Weierstrass $\wp$-function and related functions