New Estimates of Regional GDP in Spain, 1860-1930

This paper presents a new regional database on GDP in Spain for the years 1860, 1900, 1914 and 1930. Following Geary and Stark (2002), country level GDP estimates are allocated across Spanish provinces. The results are then compared with previous estimates. Further, this new evidence is used to analyze the evolution of regional inequality and convergence in the long run. According to the distribution dynamics approach suggested by Quah (1993, 1996) persistence appears as a main feature in the regional distribution of output. Therefore, in the long run no evidence of regional convergence in the Spanish economy is found.convergence, economic growth, regional gdp, distribution dynamics, economic history

Adoption and Use of Improved Maize by Small-Scale Farmers in Southeast Guatemala

This report is based on a study of the adoption and use of improved open-pollinated varieties and hybrids by small-scale farmers in the Department of Jutiapa, Guatemala. The majority of maize producers in Guatemala are small-scale subsistence farmers. Approximately 60% of the basic grains produced in the country are grown on farms that are too small to satisfy the basic nutritional needs of a typical family (5-6 persons). Increasing yields through the use of new technologies is seen as a critical step to ensuring adequate nutrition and increasing farmer income in the area. The study, conducted in June and July 1991, randomly surveyed 208 farmers in 18 municipalities of Jutiapa, apportioned according to the number of farms in each municipality. There was particular interest in assessing the impact of the Project of Generation and Transfer of Agricultural Technology and Seed Production (PROGETTAPS), which was launched in 1986 by the Instituto de Ciencia y Tecnolog�a Agr�colas (ICTA) and the General Directorate of Agricultural Services (DIGESA) with the goal of increasing small-scale farmers access to improved seeds. Study findings reveal a complex pattern of seed use in Jutiapa. Although the farmers there use several types of local and improved maize seed, they seem to prefer and use the local variety known as Arriquin, as well as two improved materials: an open-pollinated variety (B-1) and a hybrid (H-5). The reported forms of acquisition and preferences indicate that most of the farmers use the same material from 1 to 3 sowing seasons. Yield gains and relative prices, two important factors determining the profitability of adoption of new varieties, are adequate. By changing from their local varieties to OPVs and hybrids, farmers most likely can expect yield increases ranging from 35% to 70%. The decision to use improved materials in part or all of the area cropped with maize is associated with a change in the maize cropping system. Results suggest that farmers that sow a plot of maize in monoculture tend to plant the entire area with improved seed, particularly with hybrids. Results also show that the size of the family, taken together with the cropping system, is an important factor influencing the probability of full adoption, particularly of hybrid materials. The findings indicate that the probability of using hybrid materials, either in part or all of a cropped area, increases with farm size. Importantly, results from the estimating model confirmed the trend observed at the aggregate level. PROGETTAPS had a significant impact on the adoption of OPVs in Jutiapa. Farmers that have experience with PROGETTAPS are more likely to adopt OPVs than those who do not have contact with it. Furthermore, the probability of adoption increases with the years of association farmers have had with the program.Crop Production/Industries,

Bootstrapping two-loop Feynman integrals for planar N=4 sYM

We derive analytic results for the symbol of certain two-loop Feynman integrals relevant for seven- and eight-point two-loop scattering amplitudes in planar $\mathcal{N}=4$ super-Yang--Mills theory. We use a bootstrap inspired strategy, combined with a set of second-order partial differential equations that provide powerful constraints on the symbol ansatz. When the complete symbol alphabet is not available, we adopt a hybrid approach. Instead of the full function, we bootstrap a certain discontinuity for which the alphabet is known. Then we write a one-fold dispersion integral to recover the complete result. At six and seven points, we find that the individual Feynman integrals live in the same space of functions as the amplitude, which is described by the 9- and 42-letter cluster alphabets respectively. Starting at eight points however, the symbol alphabet of the MHV amplitude is insufficient for individual integrals. In particular, some of the integrals require algebraic letters involving four-mass box square-root singularities. We point out that these algebraic letters are relevant at the amplitude level directly starting with N$^2$MHV amplitudes even at one loop.Comment: 49 page

Manifesting enhanced cancellations in supergravity: integrands versus integrals

Examples of "enhanced ultraviolet cancellations" with no known standard-symmetry explanation have been found in a variety of supergravity theories. By examining one- and two-loop examples in four- and five-dimensional half-maximal supergravity, we argue that enhanced cancellations in general cannot be exhibited prior to integration. In light of this, we explore reorganizations of integrands into parts that are manifestly finite and parts that have poor power counting but integrate to zero due to integral identities. At two loops we find that in the large loop-momentum limit the required integral identities follow from Lorentz and SL(2) relabeling symmetry. We carry out a nontrivial check at four loops showing that the identities generated in this way are a complete set. We propose that at $L$ loops the combination of Lorentz and SL($L$) symmetry is sufficient for displaying enhanced cancellations when they happen, whenever the theory is known to be ultraviolet finite up to $(L-1)$ loops.Comment: 28 pages, 5 figure

Faros y luces de señalización en la navegación antigua

Los faros, como tales edificios, serán utilizados en una fase tardía de la antigüedad. Aunque su origen es incierto habría que destacar dos aspectos en su evolución: de un lado las señales luminosas realizadas mediante fuegos costeros, actividad documentada en la literatura de la época ; de otro lado las torres de vigilancia militares que pudieron constituir un paralelo arquitectónico y funcional. La escasez de restos conservados, así como la inexistencia de datos analíticos, impiden concebir hipótesis demostrables, entre ellas la utilización de señales sonoras, diurnas, etc. El estudio conjunto de materiales arqueológicos (numismática, glíptica, musivaria, etc...), Fuentes clásicas y textos de carácter mítico son fundamentales para la creación de tales hipótesis