The decline in the U.S. personal saving rate: is it real and is it a puzzle?

Since the mid-1990s, the national income and product accounts personal saving rate for the United States has been trending down, dropping into negative territory for three months during the past two years. This paper examines measurement problems surrounding two of the standard definitions of the personal saving rate. The authors conclude that, despite these measurement problems, the recent decline of the U.S. personal saving rate to low levels seems to be a real economic phenomenon and may be a cause for concern for several reasons. After examining several possible explanations for the trend advanced in the recent literature, the authors conclude that none of them provides a compelling explanation for the steep decline and negative levels of the U.S. personal saving rate.Consumer behavior ; Saving and investment

Bubbling (or just frothy) house prices?

Housing

Sizing and Energy Management of a Hybrid Locomotive Based on Flywheel and Accumulators

The French National Railways Company (SNCF) is interested in the design of a hybrid locomotive based on various storage devices (accumulator, flywheel, and ultracapacitor) and fed by a diesel generator. This paper particularly deals with the integration of a flywheel device as a storage element with a reduced-power diesel generator and accumulators on the hybrid locomotive. First, a power flow model of energy-storage elements (flywheel and accumulator) is developed to achieve the design of the whole traction system. Then, two energy-management strategies based on a frequency approach are proposed. The first strategy led us to a bad exploitation of the flywheel, whereas the second strategy provides an optimal sizing of the storage device. Finally, a comparative study of the proposed structure with a flywheel and the existing structure of the locomotive (diesel generator, accumulators, and ultracapacitors) is presented

Neighborhood income inequality

This paper offers a descriptive empirical analysis of the geographic pattern of income inequality within a sample of 359 US metropolitan areas between 1980 and 2000. Specifically, we decompose the variance of metropolitan area-level household income into two parts: one associated with the degree of variation among household incomes within neighborhoods - defined by block groups and tracts - and the other associated with the extent of variation among households in different neighborhoods. Consistent with previous work, the results reveal that the vast majority of a city’s overall income inequality - at least three quarters - is driven by within-neighborhood variation rather than between-neighborhood variation, although we find that the latter rose significantly during the 1980s, especially between block groups. We then identify a number of metropolitan area-level characteristics that are associated with both levels of and changes in the degree of each type of residential income inequality.Income distribution ; Income

EU WATER POLICY: RESEARCH DEVELOPMENTS AND NEW MANAGEMENT TOOLS

At the end of 2000, the European Commission published its Water Framework Directive (WFD) in the Official Journal of the European Communities (2000/60/EC). This new legislation provides for achieving the sustainable management of water resources through its 26 articles that focus primarily on the improvement and protection of the quality of European water resources. The WFD adopts an integrated approach, based upon general principles deriving mainly from four disciplinary approaches, Geography; Ecology; Economics and Sociology. The new challenges posed to the people responsible for the management of water resources across the European Union include the "marrying" of existing national policies with the stipulations of the WFD. Research can support this transition by identifying compatibility and conflicts between legislative instruments, and by encouraging trans-national cooperative relationships. A relevant role of research is also foreseen in providing criteria and tools for conflict resolution by representing the goals of sustainable management in an objective and transparent way. The elaboration required for making planning decisions are increasing in number and complexity, requiring tools that help to organise and communicate the data that should be used to describe the decision context in terms of sustainability, in a holistic way by including environmental, economic and social information. These problems are being addressed by the MULINO Project, a 3-year research program aiming at producing a Decision Support System that will assist water managers in responding to the evolution of policies and management methodologies. The development of the system, which will be prepared in a software format, is being steered by a group of people from European water authorities. This steering committee is contributing to the policy analysis component of the research and to the software design which aims to be applicable in five different national contexts. This paper addresses the challenges and innovations that have been encountered in the second phase of research in which the first prototype of the software has been developed to operate in specific decision situations in each of MULINO's six case studies.Sustainable water management, EU policy, DSS tool, Resource /Energy Economics and Policy,

Jeune garde : organe du Comité Internationale de Liaison pour la Construcction de l'Internationale Revolutionnaire de la Jeunesse

Títol variant: Jeune garde internationaleVILADOT-CEDO

Integrated optimal design of a hybrid locomotive with multiobjective genetic algorithms

In this paper, the Integrated Optimal Design (IOD) approach for energetic system design is discussed. IOD aims at concurrently optimizing the architecture, the element sizing and the energy management in an energetic system. IOD leads to complex optimization problems (typically mixed variable problems with several constraints and multiple objectives) which can be solved with direct optimization methods. We illustrate the interest of this approach through the design of a hybrid environmentally friendly locomotive moved by four DC motors supplied by a diesel engine generator in association with electric storage elements (batteries and ultracapacitors)

The achievement of good chemical status: an impossible mission for local water managers?

The European Water Framework Directive (2000) required to achieve good ecological and chemical status in surface waters of the EU Member States in 2015. For pesticides, this means ensuring that concentrations in rivers do not exceed 0.1 g/L per molecule and 0.5 g/L for the sum of the concentrations of the different molecules found. At national scale, EcoPhyto plan (2008) aimed to reduce pesticide use by 50% within 10. This plan has been revised and postponed to 2025 as observed pesticide use is varying between years and concentrations in river did not decrease as expected. Although vineyards cover a small percentage of agricultural land surfaces, they contribute to 20% of national pesticide use. The presence of pesticides in rivers surrounding wine territories is therefore a current environmental concern. Thus, the recovery of the water quality requires local action programs to reduce pesticide contamination in rivers. The Layon catchment comprises 13% of vineyard. It is therefore subject to an action program led by the local water committee: the SAGE Layon-Aubance-Louet. Its goal is to ensure pesticide concentrations are reduced to 1 g/L in 2018 and 0.5 g/L in 2027. In this context, one of the actions of the SAGE, with the assistance of the University of Angers, addresses the study of peaks in pesticide concentrations during runoff events in a small catchment covered by vineyards. Between 2009 and 2016, one of the two farmers has converted to organic farming with consequent decreases in pesticides input to the case study which thus complied with the EcoPhyto objectives. Results demonstrate first a peak intensity of pesticides in runoff waters in relation with the date of application with a decrease of concentrations during time after the treatment and second a relation between peaks of SPM and pesticides. Transfer of pesticides in this catchment is strongly linked to runoff. Thus, even if the increase of grass surface within vineyard improves the soil stability and decreases erosion sensitivity, it is not sufficient to stop all transfer of pesticides. Following the results of this study, neither the objectives of national policies to reduce by half the pesticide use nor the local objectives to decrease partially the un-weeded surface of vineyards would permit to achieve good chemical status, as confirmed by the current state of the water quality of the Layon river monitored by local water managers. Thus, in the continuation of all its efforts

Mass cannibalism in the Linear Pottery Culture at Herxheim (Palatinate, Germany)

The Early Neolithic central place at Herxheim is defined by a perimeter of elongated pits containing fragments of human bone, together with pottery imported from areas several hundred kilometres distant. This article offers a context for the centre, advancing strong evidence that the site was dedicated to ritual activities in which cannibalism played an important par