Early and Middle Holocene Hunter-Gatherer Occupations in Western Amazonia: The Hidden Shell Middens

We report on previously unknown early archaeological sites in the Bolivian lowlands, demonstrating for the first time early and middle Holocene human presence in western Amazonia. Multidisciplinary research in forest islands situated in seasonally-inundated savannahs has revealed stratified shell middens produced by human foragers as early as 10,000 years ago, making them the oldest archaeological sites in the region. The absence of stone resources and partial burial by recent alluvial sediments has meant that these kinds of deposits have, until now, remained unidentified. We conducted core sampling, archaeological excavations and an interdisciplinary study of the stratigraphy and recovered materials from three shell midden mounds. Based on multiple lines of evidence, including radiocarbon dating, sedimentary proxies (elements, steroids and black carbon), micromorphology and faunal analysis, we demonstrate the anthropogenic origin and antiquity of these sites. In a tropical and geomorphologically active landscape often considered challenging both for early human occupation and for the preservation of hunter-gatherer sites, the newly discovered shell middens provide evidence for early to middle Holocene occupation and illustrate the potential for identifying and interpreting early open-air archaeological sites in western Amazonia. The existence of early hunter-gatherer sites in the Bolivian lowlands sheds new light on the region's past and offers a new context within which the late Holocene "Earthmovers" of the Llanos de Moxos could have emerged. © 2013 Lombardo et al

Purinergic inhibition of Na+,K+,Cl− cotransport in C11-MDCK cells: Role of stress-activated protein kinases

Previously, we observed that sustained activation of P2Y1 leads to inhibition of Na+,K+,Cl− cotransport (NKCC) in C11 cells resembling intercalated cells from collecting ducts of the Madin-Darby canine kidney. This study examined the role of stress-activated protein kinases (SAPK) in NKCC inhibition triggered by purinergic receptors. Treatment of C11 cells with ATP led to sustained phosphorylation of SAPK such as JNK and p38. Activation of these kinases also occurred in anisomycin-treated cells. Surprisingly, we observed that compounds SP600125 and SB202190, known as potent inhibitors of JNK and p38 in cell-free systems, activated rather than inhibited phosphorylation of the kinases in C11 cells. Importantly, similarly to ATP, all the above-listed activators of JNK and p38 phosphorylation inhibited NKCC. Thus, our results suggest that activation of JNK and/or p38 contributes to NKCC suppression detected in intercalated-like cells from distal tubules after their exposure to P2Y1 agonists

The Multiple Lives of the General Relativity Community, 1955–1974

The history of general relativity presents intriguing challenges for historians and philosophers of science. Its origins and receptions have figured prominently in debates about conceptual transformations, the dynamics of theory change, relationships between theory and experiment and, of course, physical and philosophical notions of space and time

Mollusc harvesting in the Pre - European contact Pacific Islands: investigating resilience and sustainability

Mollusc shells, which are often quite numerous in archaeological sites throughout the Pacific Islands, offer good proxies for assessing environmental change as well as human impact. Documented changes in species size, richness, and abundance have often been interpreted as evidence of resource abuse by shellfish gatherers. While this may be valid in some cases, archaeologists need to consider other variables to explain change (or stability) in shell distribution. A better understanding of ecological and biological (life history) characteristics associated with shell midden deposits, as well as greater awareness of ethnographic and ethnoarchaeological data on the interaction between people and varieties of marine resources, may result in a reinterpretation of past human behavior. A growing interest in indigenous resource management among contemporary Pacific Island communities has led some archaeologists to seek tangible evidence of community resilience and sustainable use of resources in the past. This chapter draws primarily from direct observations and semi-structured interviews among mollusc gatherers in Kiribati, eastern Micronesia, and examines selected case studies of archaeological shell deposits from the Pacific Islands that could shed new light on marine resource management to complement the more widespread research conclusions that depict human impact in largely negative terms