Proposal For A Market-Based Solution to Airport Delays

With the clamor rising over airport delays and with both the Congress and the Administration considering remedies, this paper advocates the use of market mechanisms, specifically slot auctions, to promote efficient usage of airport capacity, reduce airport delays, and, more generally, promote competition.

The unemployment trap meets the age-earnings profile

The relative costs of taking employment or receiving welfare are usually understood through comparisons of a person’s social security entitlements and their wage alternative, known as replacement rates. In some situations it appears that the additional income from working is negligible, and this is said to constitute an “employment trap”. However conventional replacement rates ignore the fact that age-earnings profiles slope upward through the acquisition of labour market experience. We offer a dynamic reinterpretation and compare alternative calculations for Australia in 2000. The usual and incorrect approach exaggerates significantly the likelihood of unemployment traps, but the presence of children mitigates considerably, and can even reverse, this assessment

Community Planning Officials Survey:Understanding the everyday work of local participatory governance in Scotland

Community planning officials constitute one of the most significant groups of local public servants in Scotland today. They work across a broad range of key policy areas and are at the forefront of advancing the agenda laid out by the Christie Commission on the Future Delivery of Public Services and legislation such as the Community Empowerment (Scotland) Act. This Survey report and Executive Summary present the findings of the first survey of community planning officials (managers and officers) conducted in Scotland. Over the years improving community planning partnerships (CPPs) has often meant reforming structures and procedures; the ‘hardware’, to use a computing metaphor. Getting that right is crucial but policy, governance and public service successes often hinge on the ‘software’: relationships, mindsets, values and ways of working. Community planning officials (CPOs) operate at the heart of local governance. This survey sought to explore their views on issues related to both the ‘hardware’ and the ‘software’ of CPPs. The report has sections on: Understanding the CPO workforce Understanding the work of CPOs Using evidence Understanding how CPPs work Community engagement in community planning Frameworks, policies and reforms affecting community planning It also includes 14 recommendations focused on: developing resources and evidence to support the work of CPPs; staff development and support; improving deliberative quality in CPPs; participation and engagement; and the impact on communities and inequalities

A Statistical description of concurrent mixing and crystallisation during MORB differentiation: Implications for trace element enrichment

The pattern of trace element enrichment and variability found in differentiated suites of basalts is a sim- ple observable, which nonetheless records a wealth of information on processes occurring from the mantle to crustal magma chambers. The incompatible element contents of some mid-ocean ridge basalt (MORB) sample suites show progressive enrichment beyond the predictions of simple models of fractional crystalli- sation of a single primary melt. Explanations for this over-enrichment have focused on the differentiation processes in crustal magma chambers. In this paper we consider an additional mechanism, and focus instead on the deviation from simple fractionation trends that is possible by mixing of diverse mantle-derived melts supplied to magma chambers. A primary observation motivating this strategy is that there is significant chemical diversity in primitive high MgO basalts, which single liquid parent models cannot match. Models were developed to simulate the compositional effects of concurrent mixing and crystallisation (CMC): diverse parental melts were allowed to mix, with a likelihood that is proportional to the extent of fractional crys- tallisation. Using a simple statistical model to explore the effects of concurrent mixing and crystallisation on apparent liquid lines of descent, we show how significant departure from Rayleigh fractionation is possible as a function of the diversity of trace elements in the incoming melts, their primary MgO, and the relative proportion of enriched to depleted melts. The model was used to make predictions of gradients of trace element enrichment in log[trace element]– MgO space. These predictions were compared with observations from a compilation of global MORB and provide a test of the applicability of CMC to natural systems. We find that by considering the trace element variability of primitive MORB, its MgO content and degree of enrichment, CMC accurately predicts the pattern of trace element over-enrichment seen in global MORB. Importantly, this model shows that the relationship between over-enrichment and incompatibility can derive from mantle processes: the fact that during mantle melting maximum variability is generated in those elements with the smallest bulk K d . Magma chamber processes are therefore filtering the signal of mantle-derived chemical diversity to produce trace element over-enrichment during differentiation. Finally, we interrogate the global MORB dataset for evidence that trace element over-enrichment varies as a function of melt supply. There is no correlation between over-enrichment and melt supply in the global dataset. Trace element over-enrichment occurs at slow-spreading ridges where extensive steady-state axial magma chambers, the most likely environment for repeated episodes of replenishment, tapping and crystallisation, are very rarely detected. This supports a model whereby trace element over-enrichment is an inevitable consequence of chemically heterogeneous melts delivered from the mantle, a process that may operate across all rates of melt supply

Uber-ising access to tractors for improved productivity in Kenya and Nigeria

African agri-tech company, Hello Tractor, is using an Internet-of-Things (IoT) technology to link smallholders directly with tractor owners for increased planting times and reduced labour costs. In 2019, the company signed a contract with CTA to further develop its technology and business model

Ubériser l'accès aux tracteurs : une clé pour améliorer la productivité en Afrique subsaharienne

La pression démographique s'intensifie et pose des défis d'envergure. Les rendements des cultures devront ainsi doubler d'ici quelques années afin de garantir la sécurité alimentaire mondiale. Pour atteindre cet objectif, l'Afrique subsaharienne est une région stratégique : 60 % des terres agricoles non cultivées de la planète se situent dans cette zone. Les rendements moyens de la région demeurent bien en deçà des standards internationaux