Avanços tecnol6gicos e processos voltados para produção agricola e preservação ambiental.

bitstream/item/58254/1/6-avancos-tecnolog-Centeno-2011.pd

Source characterization variscite of Pico Centeno (Encinasola, Huelva) and study of origin of the Southwest peninsular accounts

En este trabajo estudiamos la explotación e intercambio de variscita de Pico Centeno (Encinasola, Huelva). El análisis XRD y XRF del mineral recogido en Pico Centeno durante las prospecciones arqueológicas proporcionan una impronta físico-química para cada una de las sub-fuentes localizadas durante la prospección. Estas improntas serán comparadas con otras fuentes europeas y con 50 cuentas procedentes de 8 tumbas megalíticas de dos regiones diferentes para comprobar modelos de distribución y procedencia. El mineral recuperado durante las prospecciones de Pico Centeno es variscita, mientras que las cuentas resultaron ser deminerales diversos (moscovita, talco, clorita). A la hora de comprobar la procedencia a través de la composición química encontramos que la alta variabilidad natural de los elementos traza (tradicionalmente considerados indicadores del origen) no permiten establecer la procedencia de las cuentas. Contrariamente pensamos que diferentes proporciones de fosfatos resultado de la génesis de la roca y que resultan en un cociente P/Al diferente de 1, podría ser utilizado cómo indicador del origen. Cocientes P/Al mayores de 1 no han sido descritos para ninguna otra fuente en EuropaIn this paper we discuss the exploitation and exchange of variscite at Pico Centeno source. XRF and XRD analyses of the mineral recovered at Pico Centeno mining district during archaeological survey provides a baselinemineral signature for the source and sub-sources, which were then compared to other sources and to 50 green beads from8megalithic tombs fromtwo different regions, in order to test ‘provenance postulate’ and distribution models. Mineral sampled during survey at Pico Centeno mining district turned out to be pure variscite phases, while extremely varied for the studied green beads: variscite, muscovite, talc or chlorite.We found that the concentrations of trace elements don not allow us to establish the origin of the beads, as traditionally claimed, due to the strong natural variability onminor and trace elements of the sources. Instead we found that different proportions of phosphate species, which results in P/Al ratios higher than 1, arose during the genesis of the variscite deposits. Thus, the P/Al atomic ratio should be an indication of provenance as it is established during mineral genesis. This issue has not been addressed in any of the other studied sources where this ratio seems to be ≈

A spatial mixed Poisson framework for combination of excess-of-loss and proportional reinsurance contracts

In this paper a purely theoretical reinsurance model is presented, where the reinsurance contract is assumed to be simultaneously of an excess-of-loss and of a proportional type. The stochastic structure of the set of pairs (claim’s arrival time, claim’s size) is described by a Spatial Mixed Poisson Process. By using an invariance property of the Spatial Mixed Poisson Processes, we estimate the amount that the ceding company obtains in a fixed time interval in force of the reinsurance contract

Evaluating Job Search Programs for Old and Young Individuals: Heterogeneous Impact on Unemployment Duration

This paper exploits an area-based pilot experiment to identify average treatment effects on unemployment duration of treated individuals of two active labor market programs implemented in Portugal. We focus on the short-term heterogeneous impact on two subpopulations of unemployed individuals: young (targeted by the Inserjovem program) and old (targeted by the Reage program). We show that the latter program has a small and positive impact (reduction) on unemployment duration of workers finding a job upon participation, whereas the impact of Inserjovem is generally negative (extended durations). These results are robust to a wide variety of constructions of quasi-experimental settings and estimators. The identification of heterogeneous effects showed that the program results were less satisfactory for young workers, for those over 40 and for the less educated. Women also benefited less from the programs. The results seem to improve slightly for young workers in the 2nd semester of implementation, but they deteriorate in the medium term. The lack of wage subsidies in the Portuguese programs may explain the minor impacts obtained, when compared to similar programs

Sarmiento versus Borges : diálogo de muertos

Fil: Centeno de Hoyos, Rosalía. Universidad Nacional de Cuy

USA v. Santos Centeno

USDC for the Eastern District of Pennsylvani

Manejo da cultura da soja em terras baixas em safras com El-Niño.

bitstream/CPACT-2010/13003/1/folder-manejo-elnino.pdfResponsáveis técnicos: Giovani Theisen; Francisco de Jesus Vernetti Júnior; Júlio José Centeno da Silva (CPACT)

La paja de centeno

En número dedicado a: La provincia de Segovi