Stable isotope analysis of human hair and nail samples: the effects of storage on samples

When submitting samples for analysis, maintaining sample integrity is essential. Appropriate packaging must be used to prevent damage, contamination or loss of sample. This is particularly important for stable isotope analysis by isotope ratio mass spectrometry as this technique is capable of detecting subtle differences in isotopic composition with great precision. In a novel study, scalp hair and fingernail samples were placed in five different types of packaging, routinely used in forensic laboratories and stored for 6 weeks and 6 months. Samples were subsequently cleaned and submitted for 13C/12C, 15N/14N, 2H/1H and 18O/16O analysis. Results from 13C analysis indicate that type of packaging can cause slight changes in 13C abundance over time. Differences were noted in the 15N isotope signatures of both hair and nail samples after 6-week storage, but not after 6 months. This apparent discrepancy could be a result of the packaging not being properly sealed in the 6 weeks study. Fewer differences were noted when analyzing samples for 2H and 18O abundance

Do CEOs Ever Lose? Fairness Perspective on the Allocation of Residuals Between CEOs and Shareholders

In this study we introduce a justice perspective to examining the result of bargaining between CEOs and boards over the allocation of firm residuals that ultimately determines CEO compensation. Framing CEO pay as the result of bargaining between CEOs and boards focuses attention on the power of CEOs to increase their share of firm residuals in the form of increased compensation, and the diligence of boards of directors to constrain CEO opportunism. Framing this negotiation through a theory of justice offers an alternative perspective to the search for pay-performance sensitivity. We predict and find that as board diligence in controlling opportunism declines and CEO power increases, CEOs are increasingly able to capture a larger portion of firm residuals relative to shareholders. This finding supports critics who charge that CEO pay violates norms of distributive and procedural justice

(de)Fending Art Education Through the Pedagogical Turn

This article reviews the current state of higher education in light of the pedagogical turn in contemporary art. It starts with an overview of higher education and its current struggles, followed by an outline of some of the features of the pedagogical turn in art, which is both critical of institutionalism and symptomatic of the current state of higher education. These ideas are discussed within the context of an art education graduate seminar. Finally, the argument is made for possible critical practices that take place inside the institution and that are inspired by priorities inherent in education as art projects aligned with the pedagogical turn

Hosting the Occupation of Art Education as Aporia

This article articulates an ethics of hospitality within art education that adopts an uncertain disposition to visual arts learning and affirms the unforeseeable while inviting openings for the transformation of art education knowledges and associated subjectivities. Throughout, I endeavor to keep the question of whom we teach unanswered and open, while searching for spaces of possibility within unpredictable, aporetic entanglements inherent in normalizing frameworks of art education. I contextualize Derridean notions of aporia, hospitality, monstrous arrivant, undecidability, and responsibility within the specificities of art teaching that call on us to approach the field as contradictory and ambiguous so that we might imagine the field and ourselves otherwise. Art education as an aporia must be both rule-governed and unruly, open to what may arrive to occupy our household

Anthropogenic sediments and soils: Geoarchaeology

Archaeology has gradually but consistently increased its interest in the study of soils and sediments over the last decades. As a result of this emphasis, the discipline has not only sought to characterize the terrigenous matrix within which the great majority of archaeological materials are found but, increasingly, to also understand soils and sediments in their double dimension: as archives of archaeological and environmental data and as sui generis artifacts (Butzer 1982; Waters 1992; French 2003; Holliday 2004; Goldberg & Macphail 2006; Walkington 2010). This salience notwithstanding, a tendency to conflate the meaning of sediments and soils continues to exist within the discipline. In some cases, this owes much to the nature of archaeological findings and their context; artifacts are found in sediment deposits that have stratigraphy and which, generally speaking, are sufficiently close to the surface to be affected by soil-forming processes. Be that as it may, it is useful to draw a contrast between “anthropogenic sediments” and “anthropogenic soils” (and indeed between sediments and soils) because the distinction highlights different earthly processes that can affect the formation of this type of archaeological evidence. Put another way, both anthropogenic sediments and anthropogenic soils imply terrigenous material with distinctive characteristics resulting from the strong and enduring influence of past human activity. However, each concept emphasizes a different aspect of the life history of the landscape, that demands the separate attention of archaeological research, especially the subdiscipline of geoarchaeology

Amazonian Dark Earths: Geoarchaeology

Amazonian Dark Earths (hereinafter ADEs) are expanses of anthropogenic soils that formed on generally nutrient-poor upland soils of the Amazon basin during pre-Columbian times. Expanses of ADEs range from <1–80 ha, and overall agricultural aptitude is higher than the vast majority of soils in the region. These soils are much sought after by local farmers who use them to grow specific crops. Most of the documented expanses of ADEs are found on Tertiary-age sediments located in riparian and interfluvial positions of the Amazon basin. However, instances are also reported on Quaternary alluvial sediments and on human-made earthworks, highlighting that the formation of these soils was an outcome of specific forms of pre-Columbian settlement. The discovery of ADEs alongside the main waterways of the region has been a crucial Rubicon for Amazonian archaeology: these soils record the effects of pre-Columbian indigenous societies’ creative manipulation of environmental affordances. Thus, they highlight that human inhabitation of the Amazon basin was, and is, much more than efficient adaptation to environmental limitations. Their ubiquity provides strong evidence for the existence of more sedentary and demographically denser indigenous societies in the Amazon basin before European colonization. Moreover, examined from a strictly archaeological perspective, ADEs are one of the best archaeological signatures of sedentary occupations in a region with limited archaeological preservation potential. ADEs are sui generis archaeological artifacts of extraordinary relevance for present-day concerns: soil scientists are currently studying the properties and formation of ADEs in order to develop techniques of soil amelioration that permit recuperation and amendment of degraded and infertile soils

We’re All Creatives Now: Democratized Creativity and Education

This article draws attention to and lays a critique against the relationship between creativity and neoliberalism within society, art, and education in order to both denaturalize and challenge its progression. I explore the following question: What might the implications be if contemporary education concerns itself with facilitating creativity for economic good at the expense of other conceptions of creativity? Here I confine myself to charting how creativity acts as a discursive term representing political, educational, artistic, economic, and social processes of our times. I maintain that creativity is profoundly transforming through processes of colonization and democratization associated with neoliberal economics and entrepreneurial innovation. In response to these changes, this article aims to re-appropriate creativity for education by pushing back against the current business bias with expanded meanings and purposes for creativity that do not align with creativity for industry alone

Test rig and comparison of pressure changes at transient phenomena in water- and oil-based power-control hydraulics

The use of tap water instead of the conventional hydraulic fluids in power-control hydraulics is one of possible environmentally friendly changes that we can make. In this paper we show, based on dynamic-transient parameters, both the functionality and the usability of water hydraulics in comparison to the more familiar oil hydraulics. A comparison of the dynamic behavior, oriented to pressures, between the conventional mineral hydraulic oil and the relatively new water hydraulics under the same conditions is described here. The tests were made at different flow rates (11, 22 and 33 lpm), different system pressures (70, 110 and 160 bar) and with different loads (first with a mass of 163 kg in the horizontal and vertical positions and second without this mass). Different dynamic characteristics during the pressure-surge effect of water and oil hydraulics were observed. The pressure increases were between 10 and 30 % higher in the water hydraulics than in the oil hydraulics. The frequencies of the pressure oscillations were up to 20 % lower in the water hydraulics than in the oil hydraulics

Carbon isotope fractionation during aerobic biodegradation of trichloroethene by Burkholderia cepacia G4: a tool to map degradation mechanisms

The strain Burkholderia cepacia G4 aerobically mineralized trichloroethene (TCE) to CO2 over a time period of similar to20 h. Three biodegradation experiments were conducted with different bacterial optical densities at 540 nm (OD(540)s) in order to test whether isotope fractionation was consistent. The resulting TCE degradation was 93, 83.8, and 57.2% (i.e., 7.0, 16.2, and 42.8% TCE remaining) at OD(540)s of 2.0, 1.1, and 0.6, respectively. ODs also correlated linearly with zero-order degradation rates (1.99, 1.11, and 0.64 mumol h(-1)). While initial nonequilibrium mass losses of TCE produced only minor carbon isotope shifts (expressed in per mille delta C- 13(VPDB)), they were 57.2, 39.6, and 17.0parts per thousand between the initial and final TCE levels for the three experiments, in decreasing order of their OD(540)s. Despite these strong isotope shifts, we found a largely uniform isotope fractionation. The latter is expressed with a Rayleigh enrichment factor, E, and was -18.2 when all experiments were grouped to a common point of 42.8% TCE remaining. Although, decreases of epsilon to -20.7 were observed near complete degradation, our enrichment factors were significantly more negative than those reported for anaerobic dehalogenation of TCE. This indicates typical isotope fractionation for specific enzymatic mechanisms that can help to differentiate between degradation pathways