Potassium fertilization: paradox or K management dilemma?

In 2014, Khan et al. presented evidence that soil exchangeable K (Exch-K) increases over time without addition of potassium (K) to the soil despite the removal of K in crops on a soil rich in montmorillonite and illite. The authors term this behavior ‘The potassium paradox’. From their review of the literature, the authors also report a lack of crop response to potassium chloride (KCl) fertilization. Close evaluation of these findings reveals that their observations can be interpreted and predicted using current knowledge of K in soil chemistry and its uptake by plants, and there is no paradox in K behavior in the soil–plant system. There is also no evidence of a detrimental effect of KCl on crop yield or quality. Their conclusion that the widely used Exch-K soil test is inadequate for managing K fertilization is discussed and some possible modifications to improve its performance are included. We believe that measurement of Exch-K is an essential and valuable tool and its use should be continued, along with improvements in recommending K fertilizer application

Occupying wide open spaces? Late Pleistocene hunter–gatherer activities in the Eastern Levant

With a specific focus on eastern Jordan, the Epipalaeolithic Foragers in Azraq Project explores changing hunter-gatherer strategies, behaviours and adaptations to this vast area throughout the Late Pleistocene. In particular, we examine how lifeways here (may have) differed from surrounding areas and what circumstances drew human and animal populations to the region. Integrating multiple material cultural and environmental datasets, we explore some of the strategies of these eastern Jordanian groups that resulted in changes in settlement, subsistence and interaction and, in some areas, the occupation of substantial aggregation sites. Five years of excavation at the aggregation site of Kharaneh IV suggest some very intriguing technological and social on-site activities, as well as adaptations to a dynamic landscape unlike that of today. Here we discuss particular aspects of the Kharaneh IV material record within the context of ongoing palaeoenvironmental reconstructions and place these findings in the wider spatial and temporal narratives of the Azraq Basin

New Data on the Origin of Modern Man in the Levant

Anthropolog

ARTS mediates apoptosis and regeneration of the intestinal stem cell niche

Stem cells (SCs) play a pivotal role in fueling homeostasis and regeneration. While much focus has been given to self-renewal and differentiation pathways regulating SC fate, little is known regarding the specific mechanisms utilized for their elimination. Here, we report that the pro-apoptotic protein ARTS (a Septin4 isoform) is highly expressed in cells comprising the intestinal SC niche and that its deletion protects Lgr5(+) and Paneth cells from undergoing apoptotic cell death. As a result, the Sept4/ARTS(-/-) crypt displays augmented proliferation and, in culture, generates massive cystic-like organoids due to enhanced Wnt/β-catenin signaling. Importantly, Sept4/ARTS(-/-) mice exhibit resistance against intestinal damage in a manner dependent upon Lgr5(+) SCs. Finally, we show that ARTS interacts with XIAP in intestinal crypt cells and that deletion of XIAP can abrogate Sept4/ARTS(-/-)-dependent phenotypes. Our results indicate that intestinal SCs utilize specific apoptotic proteins for their elimination, representing a unique target for regenerative medicine

Persistent Neanderthal occupation of the open-air site of ‘Ein Qashish, Israel

Over the last two decades, much of the recent efforts dedicated to the Levantine Middle Paleolithic has concentrated on the role of open-air sites in the settlement system in the region. Here focus on the site of ‘Ein Qashish as a cases study. Located in present-day northern Israel, the area of this site is estimated to have been >1300 m2, of which ca. 670 were excavated. The site is located at the confluence of the Qishon stream with a small tributary running off the eastern flanks of the Mt. Carmel. At the area of this confluence, water channels and alluvial deposits created a dynamic depositional environment. Four Archaeological Units were identified in a 4.5-m thick stratigraphic sequence were dated by Optically Stimulated Luminescence (OSL) to between—71 and 54 ka, and probably shorter time span–~70-~60 ka. Here we present the diverse material culture remains from the site (lithics, including refitted sequences; modified limestone pieces; molluscs; faunal remains) against their changing paleogeographic backdrop. Skeletal evidence suggests that these remains were associated with Neanderthals. The large-scale repeated accumulation of late Middle Paleolithic remains in the same place on the landscape provides a unique opportunity to address questions of occupation duration and intensity in open-air sites. We find that each occupation was of ephemeral nature, yet presents a range of activities, suggesting that the locale has been used as a generalized residential site rather than specialized task-specific ones. This role of ‘Ein Qashish did not change through time, suggesting that during the late Middle Paleolithic settlement system in this part of the southern Levant were stable

Modeling resilience and sustainability in ancient agricultural systems

The reasons why people adopt unsustainable agricultural practices, and the ultimate environmental implications of those practices, remain incompletely understood in the present world. Archaeology, however, offers unique datasets on coincident cultural and ecological change, and their social and environmental effects. This article applies concepts derived from ecological resilience thinking to assess the sustainability of agricultural practices as a result of long-term interactions between political, economic, and environmental systems. Using the urban center of Gordion, in central Turkey, as a case study, it is possible to identify mismatched social and ecological processes on temporal, spatial, and organizational scales, which help to resolve thresholds of resilience. Results of this analysis implicate temporal and spatial mismatches as a cause for local environmental degradation, and increasing extralocal economic pressures as an ultimate cause for the adoption of unsustainable land-use practices. This analysis suggests that a research approach that integrates environmental archaeology with a resilience perspective has considerable potential for explicating regional patterns of agricultural change and environmental degradation in the past

The Reality of Neandertal Symbolic Behavior at the Grotte du Renne, Arcy-sur-Cure, France

The question of whether symbolically mediated behavior is exclusive to modern humans or shared with anatomically archaic populations such as the Neandertals is hotly debated. At the Grotte du Renne, Arcy-sur-Cure, France, the Châtelperronian levels contain Neandertal remains and large numbers of personal ornaments, decorated bone tools and colorants, but it has been suggested that this association reflects intrusion of the symbolic artifacts from the overlying Protoaurignacian and/or of the Neandertal remains from the underlying Mousterian