The problem of calculating a degree of reputation for agents acting as assistants to the members of an electronic community is discussed and a solution presented. Usual reputation mechanisms rely on feedback after interaction between agents. An alternative way to establish reputation is related with the position of each member of a community within the corresponding social network. We propose a method based on this idea, which is also used by well-known ranking algorithms, discuss its properties as well as experimental results and compare them to other reputation mechanisms for electronic communities supported by agents. The method proposed uses only local information in order to extract reputation and it is able to adapt automatically to the topology of the network or graph.

a b s t r a c tThis article analyses the diffusion of milk consumption in Spain between 1865 and 1980, and uses a new statistical approach to estimate consumer groups and their milk consumption. This new methodology shows that these variables increased at different speeds chronologically and geographically. Two main phases can be distinguished in terms of the diffusion of milk consumption. The first phase, between the mid-19th century and the 1950s, was characterised by concentrated consumption in producer regions and big cities and the persistence of stark differences between regions. The second, between the 1950s and the 1980s, was chiefly characterised by an increase in the total number of consumers and the disappearance of these regional differences. Nueva estrategia estadística para evaluar la difusión de la leche en la población española: poblaciones consumidoras y consumo de leche, 1865-1981Códigos JEL: N34 N54 N94Palabras clave: Consumo de leche Transición nutricional España Diferencias regionales r e s u m e n En este artículo, analizamos la difusión del consumo de leche en España entre , tomando en consideración una nueva aproximación estadística para estimar las poblaciones y el consumo de leche en estos colectivos. Con la nueva metodología, mostramos que estas variables aumentaron con diferente intensidad, a lo largo del tiempo y a escala regional. Esta circunstancia nos permite distinguir dos grandes etapas en la difusión de la leche en la dieta. En la primera, hasta los años 1950, destacaría, sobre todo, el aumento del consumo en las poblaciones consumidoras y las grandes ciudades, y la pervivencia de elevados niveles de desigualdad a escala regional. En la segunda, hasta los años 1980, destacaría el aumento del número de consumidores, y la desaparición de aquellas desigualdades.

Price statistics and, in particular, food price statistics are much more abundant that those of consumption. In this article we use price statistics to analyze the qualitative variations in consumption and, specifically, the diet composition, a variable which is difficult to observe, but has remarkable implications in the evolution of living standards, health and mortality. Our analysis focuses on the years between 1910 and 1912, in a period of important changes in Spanish mortality, in order to analyze the provincial variation in the level and structure of food prices. The estimated relative price indexes suggest significant regional differences in diets which should be taken into account in living standards and mortality studies.

In this article we analyse the time course of the consumption of fresh milk in different regions of Europe between the 1870s and 1930s. Working from the case of Catalonia, we affirm that the increasing consumption of milk in that period must be especially linked to the spreading of new scientific knowledge in microbiology and nutrition that followed Pasteur's discoveries. We particularly highlight the information dissemination activities in this direction carried out by health sector professionals (medical doctors and pharmacists), governing local institutions and the milk industry. The initiatives developed by these groups changed people's preferences-fresh milk became accepted as a necessary foodstuff , and demand for it increased. However, the evolution of consumption was not the same in all regions of Europe due to their different environmental and agronomic conditions.

Abstract:In this article we discuss an aspect of economic growth that has not been the subject of much consideration in economic and agrarian history to date: the effect of biological innovations on farming development between the mid nineteenth century and the 1930s. We have focused on dairy farming for two reasons. Firstly, dairy farming played a relevant economic role in a number of European regions during this period. Secondly, one of its products, liquid milk, was probably the most significant food during the early stages of the European nutrition transition. We present new statistical data for the evolution of dairy farming in different Northern European countries as well as Spain, and evaluate the impact of cattle population and milk yields in each case. We also link milk yields and the availability of fodder, but special attention is paid to the breeds kept and techniques for their improvement. The article shows that cattle improvement played a significant role in Central and Northern Europe from the mid nineteenth century, but that this was not the case in Spain. Improvement through inbreeding was soon discarded in Spain, absorbent crossbreeding failed, and the sector became dependent on foreign imports of bulls and cows, first from Switzerland and later from Holland. By taking these factors into consideration we can better understand why the dairy sector in Mediterranean Europe did not really begin until the late nineteenth century and why it stagnated in the wake of the First World War.