Movimientos etno-campesinos en Bolivia (1985-2001)

Se analizan los avances logrados por los distintos sectores etnocampesinos de Bolivia en la última década: los pueblos originarios del oriente, los campesinos cocaleros quechuas y los campesinos aymaras kataristas del altiplano. Cuyas movilizaciones apro

La elección de Pedro Castillo: polarización, racismo y “terruqueo” en las elecciones presidenciales

The objective of the article is to analyze the electoral context of extreme political polarization that allowed the politically inexperienced Professor Pedro Castillo of the extreme left-wing party Peru Libre to win the Peruvian presidency against the extreme right-wing candidate Keiko Fujimori. The atomization of the right-wing vote, on the one hand, and the preference of the popular sectors for someone close to them, as well as their dissatisfaction with the high death toll in the pandemic, and Fujimori’s disqualifying discourse of his adversary, accusing him of being a terrorist, explain the outcome. We used newspaper sources to review the electoral process and bibliographic sources to analyze the historical background.El objetivo del artículo es de analizar el contexto electoral de polarización política extrema que permitió que el profesor Pedro Castillo, sin experiencia y capital político, del partido Perú Libre, de extrema izquierda, ganara la presidencia de Perú frente a la candidata de extrema derecha Keiko Fujimori. La atomización del voto de la derecha, por una parte, y la apuesta de los sectores populares por alguien cercano a ellos, así como su descontento frente a la alta mortandad en la pandemia, y el discurso descalificador del adversario por Fujimori acusándolo de terrorista, explican el desenlace. Se recurrió a fuentes hemerográficas, para reseñar el proceso electoral y a fuentes bibliográficas para analizar los antecedentes históricos

The social subject of the governments of Evo Morales. The new alliance

Durante las tres gestiones de gobierno de Evo Morales y más de 10 años en el poder, se ha producido un desplazamiento de sus aliados iniciales, que eran indígenas aymaras,  quechuas y de tierras bajas. Ellos han sido reemplazados como base del gobierno por otros actores, o son los mismos pero han cambiado radicalmente los atributos de su identidad, han dejado de asumirse como indígenas: son campesinos, “bartolinas”  e “interculturales”, que ahora ya no aspiran a la tierra en forma colectiva, sino a la propiedad privada. En este viraje cambiaron los sujetos y cambió el discurso gubernamental.  Sectores antes identificados con los proyectos de transformación radical ahora buscan simplemente el poder y sus beneficios. El cambio en los sujetos se expresa en los resultados del Censo Nacional de Población y Vivienda de 2012. Abordaré el desplazamiento de esos tres sectores y su participación en el Fondo Indígena.    During the three administrations of Evo Morales and over more than 10 years in power, there has been a displacement of the initial allies of the government, who were Aymaras, Quechua and lowland indigenous. They have been replaced as the base of government by other actors, or they rest the same but have radically changed the attributes of their identity, they have stopped assuming themselves as indigenous: peasants, bartolinas and intercultural, who now aspire to the land collectively, but Private property. In this turn the subjects changed and the government discourse changed aswell. Sectors formerly identified with radical transformation projects now simply seek power and to benefit from it. The change in the subjects is expressed in the results of the 2012 Census. I will address the displacement of these three sectors and their envolvement in the Indigenous Fund

Using Mg/Ca ratios from the limpet Patella depressa Pennant, 1777 measured by laser-induced breakdown spectroscopy (LIBS) to reconstruct paleoclimate

Measurement of the elemental composition of shells is increasingly emerging as an avenue for obtaining high-resolution insights into paleoclimate and past seasonality. Several studies have shown significant correlations between Mg/Ca ratios measured on shell carbonate and the sea surface temperature (SST) within which this carbonate was precipitated. However, other investigations have reported large variability in this relationship between species. Therefore, further studies, including taxa previously not considered are still required in order to validate these new species as suitable climate proxies. Here, we measured Mg/Ca ratios for limpet Patella depressa Pennant, 1777 samples live-collected in northern Spain for the first time. The elemental ratio was measured using laser-induced breakdown spectroscopy (LIBS), a technique that significantly decreases the time required for sample preparation and increases the number of shells that can be analyzed. In this study, calibration-free LIBS (CF-LIBS) methods were applied to estimate molar concentrations of chemical elements on biogenic calcium carbonate. The Mg/Ca ratio evolution along the shell growth axis was compared with stable oxygen isotope (δ18O) profiles obtained from these same limpets and the SST at the place where the mollusk grew to determine if the sequences obtained correctly reflected environmental conditions during the life-span of the mollusk. The results showed a significant correlation between Mg/Ca ratio series and both δ18O profiles and SST, highlighting the paleoenvironmental and archaeological potential of LIBS analyses on this mollusk species that is frequently found in archaeological contexts in the western Europe.This research was performed as part of the projects HAR2016-75605-R, HAR2017-86262-P and PID2019-107270RB-C21/AEI/10.13039/501100011033, funded by the Spanish Ministry of Economy and Competitiveness, MINECO. During the development of this research A.G.E was funded by the Basque Country Postdoctoral Program through a postdoctoral grant (POS_2020_2_0032). This study has also been supported by the Prehistoric Research Consolidated Group of the Basque Country University (IT-1223-19), funded by the Basque Country Government. P.R. is funded by the Max Planck Society

Automated measurement of magnesium/calcium ratios in gastropod shells using laser-induced breakdown spectroscopy for paleoclimatic applications

The chemical composition of mollusk shells offers information about environmental conditions present during the lifespan of the organism. Shells found in geological deposits and in many archeological sites can help to reconstruct past climatic conditions. For example, a correlation has been found between seawater temperature and the amount of some substituent elements (e.g., magnesium, strontium) in the biogenerated calcium carbonate matrix of the shell, although it is very species-specific. Here we propose the use laser-induced breakdown spectroscopy (LIBS) to estimate Mg/Ca ratios in modern specimens of the common limpet Patella vulgata. An automated setup was used to obtain a sequence of Mg/Ca ratios across a sampling path that could be compared with the seawater temperatures recorded during the organism's lifespan. Results using four shells collected in different months of the year showed a direct relationship between the Mg/Ca ratios and the seawater temperature, although the sequences also revealed small-scale (short-term) variability and an irregular growth rate. Nevertheless, it was possible to infer the season of capture and the minimum and maximum seawater temperatures from the LIBS sequences. This fact, along with the reduction in sampling and measurement time compared with other spectrometric techniques (such as inductively coupled plasma mass spectrometry [ICP-MS]), makes LIBS useful in paleoclimatic studies.The authors disclosed receipt of the following financial support for the research, authorship, and/or publication of this article. This research was part of the projects TEC2013-47264-C2-1-R and HAR2013-46802-P, both funded by the Spanish Ministry of Economy and Competitiveness. Asier García-Escázaga was funded by the University of Cantabria through a predoctoral grant and Igor Gutierrez-Zugasti was supported by the Juan de la Cierva programme (JCI-2012-12094) funded by the Spanish Ministry of Economy and Competitiveness

Bayesian estimates of marine radiocarbon reservoir effect in northern Iberia during the Early and Middle Holocene

Reconstructing the past variability of marine radiocarbon reservoir effects (MRE) is crucial for generating reliable chronologies for marine species and their consumers. We investigated the temporal MRE variability at the Early-to Mid-Holocene site of El Mazo (Asturias, northern Spain) by using a combination of new and previously published radiocarbon measurements on marine and terrestrial samples. The El Mazo site is characterized by overall well-defined archaeological layers of unknown occupation length with the predominant presence of two mollusc species (Patella vulgata Linnaeus, 1758 and topshell Phorcus lineatus [da Costa, 1778]) which were analysed for radiocarbon measurements. We employed the recently released IntCal20 calibration curve for the northern hemisphere and Bayesian modelling to reconstruct the site?s chronology and temporal variability in MREs according to mollusc species. Obtained radiocarbon modelling results, although the estimate precision is not high, reveal a temporal variability in MREs that can be interpreted in view of known past climatic and environmental events such as the 8.2 ka event. The results also revealed differences in MREs according to mollusc species, which need to be taken into account in future chronological modelling. Overall, our results provide reference MRE values for the study of chronologies in northern Iberia during the Early-to Mid-Holocene. In this respect, a non-conservative ?R reference for local marine samples dating earlier than c. 8.1 ka cal BP is - 238 ± 28 14C years.This research was performed as part of the projects HAR 2016- 75605-R and HAR 2017-86262-P, funded by the Spanish Ministry of Economy and Competitiveness, MINECO. During the development of this research AGE was funded by the Basque Country Postdoctoral Programme through a postdoctoral grant (POS_2020_2_0032) and University of La Rioja (no code available). This study has also been supported by the Prehistoric Research Consolidated Group of the Basque Country University (IT-1223-19), funded by the Basque Country Government. PR and RF are funded by the Max Planck Society. We thank the Fishing Activity Service of the Cantabrian Government for the authorization to collect modern specimens. We also thank the Max Plank Society, University of La Rioja, Basque Country University (UPV/EHU), University of Cantabria (UC) and Instituto Internacional de Investigaciones Prehist´oricas de Cantabria (IIIPC) for providing support

Growth patterns of the topshell Phorcus lineatus (da Costa, 1778) in northern Iberia deduced from shell sclerochronology

Combined shell growth pattern and oxygen isotope analysis has become a powerful approach in palaeoclimate and archaeological studies for reconstructing palaeoclimate conditions and littoral exploitation patterns, respectively. Recent investigations have shown that the gastropod Phorcus lineatus (da Costa, 1778) forms its shell in conditions of near equilibrium with the oxygen isotope signature of the seawater environment, demonstrating the utility of this species for reconstruction of sea surface temperature and determination of the season of harvest in archaeological studies. In contrast, the shell growth patterns of this species have received virtually no attention despite providing information on the rate and timing of shell growth that is crucial for correctly interpreting environmental proxies derived from shell geochemistry. In this paper, we compare microgrowth patterns and isotopic profiles of four modern individuals of the gastropod P. lineatus from northern Iberia to determine the timing and periodicity of subannual growth markers within the shells. Results of this sclerochronological study showed the presence of two types of growth lines/increments: i) large-scale accretionary units formed with variable periodicity, and ii) small-scale accretionary units formed by micro growth lines and increments determined by semidiurnal tidal cycles. Results suggest that shells grew uninterruptedly during early ontogeny. However, older specimens exhibited growth cessation/slowdown during summer and winter/spring. Therefore, shell growth rate is not only controlled by environmental conditions, but also by ontogenetic age and/or endogenous rhythms. A high correlation was found between seawater temperature derived from shell oxygen isotopes and instrumental seawater temperature (r2 = 0.88–0.98; p-values < 0.0001). This study shows that establishing accurate growth patterns of the topshell P. lineatus is essential for correctly reconstructing past seawater temperature conditions in palaeoclimate studies and for determining with higher precision the season(s) when the subfossil shells were collected by humans.This research was performed as part of the project TRACECHANGE: Tracing Climatic Abrupt Change Events and their Social Impact during the Late Pleistocene and Early Holocene (15–7 ky cal BP) (2014–2016) (HAR2013-46802-P), funded by the Spanish Ministry of Economy and Competitiveness, MINECO. AGE was funded by the University of Cantabria through a predoctoral grant (no code available). IGZ was also supported by the Juan de la Cierva Research Programme (grant number JCI-2012-12094) funded by the MINECO

Stable oxygen isotope analysis of Phorcus lineatus (da Costa, 1778) as a proxy for foraging seasonality during the Mesolithic in northern Iberia

The Mesolithic period in the Cantabrian region, a coastal area located in northern Spain, is characterised by a marked increase in the human use of coastal resources in comparison with previous periods, resulting in the formation of so-called "shell middens". Archaeological investigations have provided insights into the formation processes of these shell middens, as well as long-term changes in human exploitation of different marine resources and the relationship of foraging strategies to past climate changes. However, efforts to reconstruct the key environmental factor governing coastal subsistence and foraging resilience, the seasonal availability and use of different marine resources, have been limited in the region and, indeed, across coastal Mesolithic Europe more widely. Here, we use stable oxygen isotope analysis of Phorcus lineatus (da Costa, 1778), one of the most widespread molluscs in northern Iberian mesolithic coastal sites, in order to determine the season in which humans collected key coastal resources at the site of EL Mazo (Llanes, Asturias). We demonstrate that P. lineatus was exclusively collected in late autumn, winter and early spring. An experimental programme, in which modern P. lineatus specimens were collected in situ over the course of three years, established that relative meat yield varied within this species throughout the annual cycle, with higher relative meat yield during colder months. We argue that mollusc collection patterns were driven by a cost-benefit principle during the Mesolithic in the Cantabrian region and human populations had intimate knowledge of the seasonal developmental cycles of exploited marine taxa. This also highlights the importance of developing intra-annual records of resource use and climate change if coastal foraging is to be properly understood in prehistory.This research was performed as part of the projects HAR2016-75605-R and HAR2017-86262-P, funded by the Spanish Ministry of Economy and Competitiveness, MINECO. During the development of this research, AGE was funded by the University of Cantabria through a pre-doctoral grant (no code available) and is currently supported by the Basque Country Postdoctoral Programme (grant number POS_2018_1_0016). DCS was supported by the Juan de la Cierva Research Programme (IJCI-2014-20590) of the Spanish Ministry of Economy and Competitiveness

Marine Radiocarbon Reservoir Effect in Late Pleistocene and Early Holocene Coastal Waters off Northern Iberia

Radiocarbon dating of closely associated marine mollusk shells and terrestrial material (mammal bones or charred wood) collected from archaeological contexts in northern Atlantic Iberian coastal areas is used to quantify the marine 14C reservoir effect (ΔR) for the coastal waters off the Cantabrian coast (northern Iberia). For the first time, ΔR values were reliably determined for these coastal waters, and also for the first time a ΔR was calculated for the Late Pleistocene in Atlantic Iberia. Pairs of coeval samples of different carbon reservoirs selected from Upper Paleolithic (Late Pleistocene) and Mesolithic (Early Holocene) contexts yielded ΔR weighted mean values of −117±70 14C yr and −105±21 14C yr, respectively. These values show oceanographic conditions characterized by a reduced offset between atmospheric and surface water 14C contents, suggesting a nonexistent or a very weak upwelling and some stratification of the water column. Similar oceanographic conditions have been recorded in other areas of Atlantic Iberia during the Holocene, such as off Andalusian and northwestern Galician coasts. Results not only provide useful information on environmental conditions but also a framework to obtain more precise and reliable absolute chronologies for the Late Pleistocene and Early Holocene in northern Iberia

Mg/Ca profiles within archaeological mollusc (Patella vulgata) shells: Laser-Induced Breakdown Spectroscopy compared to Inductively Coupled Plasma-Optical Emission Spectrometry

© 2018 Elsevier B.V. Biogenic carbonate mollusc shells have the unique property of being a durable material found in many archaeological and geological sites, recording in their shell chemical composition the ambient environmental conditions during the mollusc's lifespan. In particular, mollusc shell Mg/Ca ratios have been suggested to be related to seawater temperature, although such a relationship is controversial and appears to be species- and even location-specific. This study investigates the use of Laser-Induced Breakdown Spectroscopy (LIBS) for the rapid measurement of Mg/Ca profiles within Patella vulgata shells, via comparison with one established analytical technique that is most often used for this purpose, ICP-OES. LIBS offers some advantages over other spectrometric techniques, including ICP-OES, the latter requiring initial micromilling of sample powders. LIBS offers faster measurement, reduced sample preparation, easier automation and less complex and lower cost instrumentation. A high correlation is evident between LIBS and ICP-OES Mg/Ca profiles within four archaeological P. vulgata shells, as well as strong similarities between LIBS measurements made in two different areas of each P. vulgata shell (i.e. the apex and a more conventional transect along the axis of shell growth). Validation of the LIBS technique for determination of Mg/Ca profiles within P. vulgata shells has implications for archaeological studies, because a greater number of shell specimens sampled from each archaeological site and chronological level can be measured, thereby improving the statistical robustness of data interpretation and conclusions. One example archaeological application that would benefit from application of the LIBS technique is identification of the season-of-capture of marine molluscs as a food resource for prehistoric societies