Let's go fishing: A quantitative analysis of subsistence choices with a special focus on mixed economies among small-scale societies.

The transition to agriculture is regarded as a major turning point in human history. In the present contribution we propose to look at it through the lens of ethnographic data by means of a machine learning approach. More specifically, we analyse both the subsistence economies and the socioecological context of 1290 societies documented in the Ethnographic Atlas with a threefold purpose: (i) to better understand the variability and success of human economic choices; (ii) to assess the role of environmental settings in the configuration of the different subsistence economies; and (iii) to examine the relevance of fishing in the development of viable alternatives to cultivation. All data were extracted from the publicly available cross-cultural database D-PLACE. Our results suggest that not all subsistence combinations are viable, existing just a subset of successful economic choices that appear recurrently in specific ecological systems. The subsistence economies identified are classified as either primary or mixed economies in accordance with an information-entropy-based quantitative criterion that determines their degree of diversification. Remarkably, according to our results, mixed economies are not a marginal choice, as they constitute 25% of the cases in our data sample. In addition, fishing seems to be a key element in the configuration of mixed economies, as it is present across all of them.

Quantifying the relationship between food sharing practices and socio-ecological variables in small-scale societies: A cross-cultural multi-methodological approach.

This article presents a cross-cultural study of the relationship among the subsistence strategies, the environmental setting and the food sharing practices of 22 modern small-scale societies located in America (n = 18) and Siberia (n = 4). Ecological, geographical and economic variables of these societies were extracted from specialized literature and the publicly available D-PLACE database. The approach proposed comprises a variety of quantitative methods, ranging from exploratory techniques aimed at capturing relationships of any type between variables, to network theory and supervised-learning predictive modelling. Results provided by all techniques consistently show that the differences observed in food sharing practices across the sampled populations cannot be explained just by the differential distribution of ecological, geographical and economic variables. Food sharing has to be interpreted as a more complex cultural phenomenon, whose variation over time and space cannot be ascribed only to local adaptation.

Hunter-gatherer mobility and technological landscapes in southernmost South America: a statistical learning approach.

The present work aims to quantitatively explore and understand the relationship between mobility types (nautical versus pedestrian), specific technological traits and shared technological knowledge in pedestrian hunter-gatherer and nautical hunter-fisher-gatherer societies from the southernmost portion of South America. To that end, advanced statistical learning techniques are used: state-of-the-art classification algorithms and variable importance analyses. Results show a strong relationship between technological knowledge, traits and mobility types. Occupations can be accurately classified into nautical and pedestrian due to the existence of a non-trivial pattern between mobility and a relatively small fraction of variables from some specific technological categories. Cases where the best-fitted classification algorithm fails to generalize are found significantly interesting. These instances can unveil lack of information, not enough entries in the training set, singular features or ambiguity, the latter case being a possible indicator of the interaction between nautical and pedestrian societies.

Effect of resource spatial correlation and hunter-fisher-gatherer mobility on social cooperation in Tierra del Fuego.

This article presents an agent-based model designed to explore the development of cooperation in hunter-fisher-gatherer societies that face a dilemma of sharing an unpredictable resource that is randomly distributed in space. The model is a stylised abstraction of the Yamana society, which inhabited the channels and islands of the southernmost part of Tierra del Fuego (Argentina-Chile). According to ethnographic sources, the Yamana developed cooperative behaviour supported by an indirect reciprocity mechanism: whenever someone found an extraordinary confluence of resources, such as a beached whale, they would use smoke signals to announce their find, bringing people together to share food and exchange different types of social capital. The model provides insight on how the spatial concentration of beachings and agents' movements in the space can influence cooperation. We conclude that the emergence of informal and dynamic communities that operate as a vigilance network preserves cooperation and makes defection very costly.

El entrenador como mentor de jugadores en formación: un estudio de relaciones entrenador-deportista positivas / The coach as youth player´s mentor: study of positivy coach-athlete relationships

El presente trabajo busca analizar el rol del entrenador como mentor de deportistas en etapas de formación en baloncesto. Para ello se ha realizado un estudio cualitativo de 12 díadas entrenador deportista (N=24) seleccionadas deliberadamente, discriminando variables establecidas por la literatura específica como criterios determinantes para la mejora de la relación (nivel deportivo del equipo, características del entrenador, duración de la relación y calidad de la misma). Los resultados muestran cómo diferentes componentes de la relación inciden en el crecimiento personal por parte de los jugadores, fruto de una relación cercana y basada en el apoyo y cuidado de aspectos de carácter extradeportivo (AU)

The aim of this paper is to analyse the role of the coach as mentor of basketball youth players. A qualitative study was conducted. The sample (12 dyads coach-athlete, N=24) was deliberately selected, discriminating variables set by the specific literature as determining criteria for improving the relationship (sports team level, characteristics of the coach, duration of the relationship, and quality of the relationship). Results revealed the influence of the different components of the relationship in players’ personal growth, as a result of a close relationship based on support and personal care (AU)

Salt stress enhances xylem development and expression of S-adenosyl-L-methionine synthase in lignifying tissues of tomato plants.

S-Adenosyl-L-methionine synthase (SAM; ATP: L-methionine adenosyltransferase, EC 2.5.1.6) catalyzes the biosynthesis of S-adenosyl-L-methionine (AdoMet), a universal methyl-group donor. This enzyme is induced by salinity stress in tomato (Lycopersicon esculentum Mill.). To elucidate the role of SAM and AdoMet in the adaptation of plants to a saline environment, the expression pattern and histological distribution of SAM was investigated in control and salt-stressed tomato plants. Immunohistochemical analysis showed that SAM proteins were expressed in all cell types and plant organs, albeit with preferential accumulation in lignified tissues. Lignin deposition was estimated by histochemical tests and the extent of tissue lignification in response to salinity was quantified by image analysis. The average number of lignified cells in vascular bundles was significantly greater in plants under salt stress, with a maximal expansion of the lignified area found in the root vasculature. Accordingly, the greatest abundance of SAM gene transcripts and proteins occurred in roots. These results indicate that increased SAM activity correlated with a greater deposition of lignin in the vascular tissues of plants under salinity stress. A model is proposed in which an increased number of lignified tracheary elements in tomato roots under salt stress may enhance the cell-to-cell pathway for water transport, which would impart greater selectivity and reduced ion uptake, and compensate for diminished bulk flow of water and solutes along the apoplastic pathway.