Guanaco (Lama guanicoe) isotopic ecology in southern South America: spatial and temporal tendencies, and archaeological implications

We synthesize and discuss available isotopic data on Holocene guanaco samples from southern South America, extending from Tierra del Fuego Island to northern Patagonia and the Pampean region. We evaluate temporal and spatial tendencies on the basis of 91 samples (mainly based on δ¹³C_collagen values), presenting implications for paleodietary research in archaeology. We conclude that there are no strong correlations with latitude in the macro-spatial scale, while there is a set of interesting patterns at smaller regional scales. These patterns lead us to evaluate the role of ecologic and topographic variables (e.g. canopy effect, variations in altitude, ecotones) in structuring isotopic variability. Finally, on the basis of the present analysis we suggest a number of hypotheses and perspectives for the use of stable isotopes as geographic tracers of guanaco distribution in the past, and specific implications for the paleodietary study of human samples.     

The geological methane budget at Continental Margins and its influence on climate change

Geological methane, generated by microbial decay and the thermogenic breakdown of organic matter, migrates towards the surface (seabed) to be trapped in reservoirs, sequestered by gas hydrates or escape through natural gas seeps or mud volcanoes (via ebullition). The total annual geological contribution to the atmosphere is estimated as 16–40 Terragrammes (Tg) methane; much of this natural flux is ‘fossil’ in origin. Emissions are affected by surface conditions (particularly the extent of ice sheets and permafrost), eustatic sea‐level and ocean bottom‐water temperatures. However, the different reservoirs and pathways are affected in different ways. Consequently, geological sources provide both positive and negative feedback to global warming and global cooling. Gas hydrates are not the only geological contributors to feedback. It is suggested that, together, these geological sources and reservoirs influence the direction and speed of global climate change, and constrain the extremes of climate.     

Company Growth,Acquisitions and Access to Complementary Assets in Israel's Data Security Sector

This article analyses aspects of high-tech cluster emergence in Israel during the 1990s with focuses on the data security software industry and on strategies of very successful companies dominating such an industry. Most of the industry is concentrated in Tel Aviv and close-by Hertzliya and to a lesser extent Haifa and Jerusalem. It starts by characterizing the industry as a whole and the universe of 19 companies comprising it. It then proceeds with an in-depth analysis of the growth trajectories of very successful companies, some of which are listed in NASDAQ or have been acquired by large multinational corporations. A fast 'IPO' and a 'fast M&A' track have been identified and characterized. The analysis suggests that while globalization could be beneficial to skill intensive peripheral economies like Israel, a significant economic impact may require an appropriate balance between start-up activity and downstream production and marketing activities.     

Peopling the Recent Past in the Serra de L’Altmirant: Shepherds and Farmers at the Margins

The region of the Serra de l’Altmirant in southeastern Spain, through its upland location and its rocky and scrub landscape, is strongly perceived as marginal–this mainly in contrast with the nearby fertile coastal plains between Valencia and Denia, busy with orange and vine production especially. A progressive colonization of the lower part of the Serra by weekend homes is starting to counter this image of marginality, but at the same time such constructions threaten the residual archaeology of a different type of human upland exploitation, namely pastoralism and hunting. Abandoned terraces, cisterns, store buildings and larger corrals are evident even on the exposed plateau and testify to a period in which the Serra was active and integral to farmers and shepherds from the villages of the adjoining valleys and plains. This paper discusses the nature of this activity, as recorded through archaeological and ethnographic investigation, and considers also the materials and outlook of Manolo, the last shepherd-in-residence on the Serra.