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Emergence of portable X-ray fluorescence (pXRF) systems presents new opportunities for rapid, low-cost plant analysis, both as a lab system and in situ system. Numerous studies have extolled the virtues of using pXRF for a wide range of plant applications, however, for many such applications, there is need for further assessment with regards to analytical parameters for plant analysis. While pXRF is a potential powerful research tool for elemental composition analysis, its successful use in plant analysis is made more likely by having an understanding of X-ray physics, calibration process, and ability to test a variety of homogenous and well-characterized materials for developing a matrix-specific calibration. Because potential pXRF users may often underestimate the complexity of proper analysis, this study aims at providing a technical background for plant analysis using pXRF. The focus is on elemental quantification under different analytical parameters and different methods of sample presentation: direct surface contact under vacuum, placement in a sample cup with prolene as a seal, and without the aid of a vacuum. Direct analysis on the surface of a pXRF provided highest sensitivity and accuracy (R 2 > 0.90) for light elements (Mg to P). Sulfur, K, and Ca can be reliably measured without the aid of a vacuum (R 2 > 0.99, 0.97, and 0.93 respectively), although lower detection limits may be compromised. pXRF instruments provide plant data of sufficient accuracy for many applications and will reduce the overall time and budget compared with the use of conventional techniques. Sensitivity and accuracy are dependent on the instrument's settings, make, and model. © 2015 The Authors. X-Ray Spectrometry published by John Wiley & Sons, Ltd.Additional supporting information may found in the online version of this article at publisher's web site. IntroductionKey plant nutrients, including potassium (K), phosphorus (P), and sulfur (S), play important roles in regulating processes such as photosynthesis, carbon respiration, and tissue building. Elemental analysis of plants is critical to plant studies and agriculture. However, despite the routine application of digestion-based analytical techniques in many laboratories, the slow and often hazardous sample digestion process can present a challenge in the analyses of plant nutrients, particularly where hundreds or even thousands of samples are to be analysed.[1] The conventional plant elemental analyses based on plant extracts are cumbersome and of variable accuracy and present major limitations to exploiting the full potential of plant nutrient analysis. An ideal system for analysis would include accuracy, replicability, portability, and minimal sample preparation. The technology that currently provides the best option to meet these needs is energy-dispersive X-ray fluorescence (ED-XRF), particularly in the form of a portable instrument portable X-ray fluorescence (pXRF). These instruments are commonly used for scrap metal sourcing, [2] geochemical provenience of obsidian,...

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Despite increasing interest in the relationship between culture transformation and abrupt climate change, their complexities are poorly understood. The local impact of global environmental fluctuations depends on multiple factors, and their effects on societal collapse are often assumed rather than demonstrated. One of the major changes in west European later prehistory was the Copper to Bronze Age transition in the early second millennium BC, contemporaneous with the 4.2 ky cal. BP event. This article offers a multi-dimensional insight into this historical process in the Iberian Peninsula from a multi-proxy and comparative perspective. Three study areas, representative of diverse ecological settings and historical trajectories, are compared. Using radiocarbon dates, 13 C discrimination (Δ 13 C) values on C3 plants, and high-resolution palynological records as

In archaeology, we are accustomed to investing great effort into collecting data from fieldwork, museum collections, and other sources, followed by detailed description, rigorous analysis, and in many cases ending with publication of our findings in short, highly concentrated reports or journal articles. Very often, these publications are all that is visible of this lengthy process, and even then, most of our journal articles are only accessible to scholars at institutions paying subscription fees to the journal publishers. While this traditional model of the archaeological research process has long been effective at generating new knowledge about our past, it is increasingly at odds with current norms of practice in other sciences. Often described as ‘open science’, these new norms include data stewardship instead of data ownership, transparency in the analysis process instead of secrecy, and public involvement instead of exclusion. While the concept of open science is not new in archaeology (e.g., see Lake 2012 and other papers in that volume), a less transparent model often prevails, unfortunately. We believe that there is much to be gained, both for individual researchers and for the discipline, from broader application of open science practices. In this article, we very briefly describe these practices and their benefits to researchers. We introduce the Society of American Archaeology’s Open Science Interest Group (OSIG) as a community to help archaeologists engage in and benefit from open science practices, and describe how it will facilitate the adoption of open science in archaeology.

This paper assesses long-term trends in human activity across the Iberian Peninsula associated with the spread of agriculture. In order to improve our understanding of regional trajectories within the two-way and multiple-velocity model proposed by Isern et al. (Journal of Archaeological Method and Theory 21:447-460, 2014), we consider summed calibrated radiocarbon dates of a large audited dataset from across Iberia. To assess the role of different analytical units, two alternative peninsular divisions at different spatial resolutions were used: one, with three generalized study areas, and the second, with eight biogeographic regions. This comparison of spatiotemporal variability provides a more in-depth inter-regional reading of the Neolithic transition in Iberia than more generalized approaches. The southwest, Mediterranean coasts and interior portions of Iberia all showed significant demographic expansion with the onset of the Neolithic, as observed across Western Europe. By contrast, northern Iberia featured a close adherence to a null model of exponential growth and a longer continuation of hunter-gatherer strategies.

From 1890 to 2015, anthropogenic carbon dioxide emissions have increased atmospheric CO concentrations from 270 to 400 mol mol . The effect of increased carbon emissions on plant growth and reproduction has been the subject of study of free-air CO enrichment (FACE) experiments. These experiments have found (i) an increase in internal CO partial pressure (c ) alongside acclimation of photosynthetic capacity, (ii) variable decreases in stomatal conductance, and (iii) that increases in yield do not increase commensurate with CO concentrations. Our data set, which includes a 115-year-long selection of grasses collected in New Mexico since 1892, is consistent with an increased c as a response to historical CO increase in the atmosphere, with invasive species showing the largest increase. Comparison with Palmer Drought Sensitivity Index (PDSI) for New Mexico indicates a moderate correlation with Δ C (r = 0.32, P < 0.01) before 1950, with no correlation (r = 0.00, P = 0.91) after 1950. These results indicate that increased c may have conferred some drought resistance to these grasses through increased availability of CO in the event of reduced stomatal conductance in response to short-term water shortage. Comparison with C trees from arid environments (Pinus longaeva and Pinus edulis in the US Southwest) as well as from wetter environments (Bromus and Poa grasses in New Mexico) suggests differing responses based on environment; arid environments in New Mexico see increased intrinsic water use efficiency (WUE) in response to historic elevated CO while wetter environments see increased c . This study suggests that (i) the observed increases in c in FACE experiments are consistent with historical CO increases and (ii) the CO increase influences plant sensitivity to water shortage, through either increased WUE or c in arid and wet environments, respectively.