关于城市物流的运营系统及其构成

城市物流的引入是为了应对全球范围内城市化和爆炸式增长的城市交通所带来的挑战。它提出了一系列措施,如通过整合运输、环境保护和经济增长等来提升城市货物流通效率,从而实现城市可持续发展战略。城市物流的运营系统包括城市运输领域的所有相关部分,并整合了所有的物流服务环节,如城市集运中心、最后一公里配送和逆向物流等。本文阐述了如何实施该运营系统,以全球领先的物流公司的大量实践说明其带来的益处。     

Farmers at the heart of the ‘human capital revolution’? Decomposing the numeracy increase in early modern Europe†

Did the early development of skills and numerical abilities occur primarily in urban centres and among the elite groups of society? This study assesses the human capital of different occupational groups in the early modern period and partially confirms this finding: skilled and professional groups had higher levels of numeracy and literacy than persons in unskilled occupations. However, there was another large group that developed substantial human capital and represented around one‐third of the total population: farmers. By analysing numeracy and literacy evidence from six countries in Europe and Latin America, we argue that farmers contributed significantly to the formation of human capital and, consequently, to modern economic growth.     

The concept of Ro in epidemic theory

In epidemiology R₀ denotes the average number of secondary cases of an infectious disease that one case would generate in a completely susceptible population. This concept is among the foremost and most valuable ideas that mathematical thinking has brought to epidemic theory. In this contribution, we first review the historical development of Ro, from demography to epidemiology, proceed to give an exposition of the recently formalised theory to define and calculate R₀ for structured populations, return to the interaction of demography and epidemiology for an example of the use of the concept to study vaccination campaigns and finally we deal with statistical aspects of estimating R₀ . In the appendix we discuss some issues of current attention.     

Brain drain in the age of mass migration: Does relative inequality explain migrant selectivity?

Brain drain is a core economic policy problem for many developing countries today. Does relative inequality in source and destination countries influence the brain-drain phenomenon? We explore human capital selectivity during the period 1820–1909.We apply age heaping techniques to measure human capital selectivity of international migrants. In a sample of 52 source and five destination countries we find selective migration determined by relative anthropometric inequality in source and destination countries. Other inequality measures confirm this. The results remain robust in OLS and Arellano–Bond approaches. We confirm the Roy–Borjas model of migrant self-selection. Moreover, we find that countries like Germany and UK experienced a small positive effect, because the less educated emigrated in larger numbers.     

Evolution of living standards and human capital in China in the 18-20th centuries: Evidences from real wages, age-heaping, and anthropometrics

This article mobilizes and integrates both existing and new time series data on real wages, physical heights and age-heaping to examine the long-term trend of living standards and human capital for China during the eighteenth to twentieth centuries. Our findings confirm the existence of a substantial gap in living standards between China and North-western Europe in the eighteenth and nineteenth centuries. They also reveal a sustained decline in living standards and human capital at least in South China from the mid-nineteenth century followed by a recovery in the early twentieth century. However, comparative examination of age-heaping data shows that the level of Chinese human capital was relatively high by world standard during this period. We make a preliminary exploration of the historical implication of our findings.     

US dollar and D-Mark as reserve assets

Zusammenfassung US-Dollar und D-Mark als Reservew?hrung. — Der Autor verwendet ein Modell der Diversifizierung von W?hrungsreserven, das auf der Vorstellung beruht, da\ die Diversifizierung weg vom Dollar haupts?chlich durch den Wegfall der Konvertibilit?tsbeschr?nkung für offizielle Dollarreserven verursacht worden sei. Aus der Untersuchung geht hervor, da\ diese Beschr?nkung wiederhergestellt wurde, nachdem sich die D-Mark zu einer zweiten Reservew?hrung entwickelt hatte, wobei die dominierende Rolle des Dollars auf der Gr?\e der amerikanischen Wirtschaft und ihres Kapitalmarkts beruht, w?hrend die D-Mark ihre zunehmende Bedeutung ihrem Ruf als berechenbare W?hrung mit niedriger Inflationsrate verdankt. Demnach kann die Diversifizierung von W?hrungsreserven als ein stabilisierendes Element im internationalen W?hrungssystem angesehen werden.

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Résumé US dollar et DM comme réserves monétaires. — Cette étude présente un modèle concernant la diversification des réserves basé sur l’opinion que la diversification des réserves de dollar était principalement causée par l’abolition de la contrainte de convertibilité aux réserves officielles de dollar. L’analyse propose que cette contrainte a été réétablie par l’évolution de la DM comme une deuxième réserve monétaire principale — en attribuant le róle dominant du dollar à l’importance de l’économie américaine et de son marché des capitaux et le róle augmentant de la DM à son réputation comme une monnaie prédisable d’une inflation basse. C’est pourquoi on peut regarder la diversification des réserves comme un élément qui stabilise le système monétaire international.

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Resumen El dólar EE.UU. y el marco alemán como activos de réserva. — En este trabajo se presenta un modelo de diversificatión de reservas basado en la opinion que la diversificatión hacia activos en monedas alternativas al dólar fué causada por la abolición de la restriction sobre la convertibilidad de reservas oficiales en dólares. El análisis sugiere que esta restrictión fué reestablecida a raiz de la evolución del marco alemán hasta llegar a ser la segunda moneda de reserva en el mundo, atribuyéndole el papel dominante del dólar al tama?o de la economia de los EE.UU. y a su mercado de capitales, y el creciente papel del marco alemán a su reputación como moneda predecible y de baja inflación. La diversificación de réservas puede por ello ser considerada como un elemento estabilizador en el sistema monetario international.

     

A story of large landowners and math skills: Inequality and human capital formation in long-run development, 1820–2000

We create a new dataset to test the influence of land inequality on long-run human capital formation in a global cross-country study and assess the importance of land inequality relative to income inequality. Our results show that early land inequality has a detrimental influence on math and science skills even a century later. We find that this influence is causal, using an instrumental variable (IV) approach with geological, climatic and other variables that are intrinsically exogenous. A second major contribution of our study is our assessment of the persistence of numerical cognitive skills, which are an important component of modern human capital measures. Early numeracy around 1820 is estimated using the age-heaping strategy. We argue that countries with early investments in numerical education entered a path-dependency of human capital-intensive industries, including skill-intensive agriculture and services. The combined long-run effects of land inequality and human capital path-dependence are assessed for the first time in this article.