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

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

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

Inoperative Art Education

Increasingly, assessment has encroached on art education, inextricably linking visual arts learning to standardized performances wherein, art educators are becoming technicians accountable to the neoliberal state of education. Under these circumstances, the authors’ hearts and minds are understandably heavy for a postponement of art education as usual, proposing the question: Given the permission to escape art education’s current workings, what might art educators abandon, and how might they undertake this? IN order to delve into this provocation, the authors propose a limbo space of deferral in relation to art education that might inspire any predetermined usages inoperable. From this paradoxical zone, the final destination of art education under economic rationales may be suspended so that art educators might studiously play with its norms. The authors offer poetic and sculptural forms that misuse aspects of art education to explore its possible im-potentialities going against the grain of neoliberal logics

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

Detection of contagious caprine pleuropneumonia in East Turkey

A study was implemented to investigate the presence of contagious caprine pleuropneumonia (CCPP) in East Turkey. This study was based on clinical surveillance in the field, surveillance at regional slaughterhouses and regular submission of suspected lesions to regional laboratories. The results showed that the agent of CCPP, Mycoplasma capricolum subspecies capripneumoniae (Mccp), could be detected by culture and specific polymerase chain reaction from 37.5% (12/32) of lung samples taken from goats of ten different herds. This agent was also isolated from two of 13 sheep samples (one from the lung and the other from a nasal swab). Mycoplasma capricolum subsp. capripneumoniae was isolated in pure culture and characterised at a finer molecular level. The East Turkish isolate was found to be closely related to another strain of Turkish origin, as well as to Mccp strains isolated in Tunisia. The isolation of Mccp from sheep lung lesions brings the strict host-specificity of this pathogen into question. It may also indicate that Mccp presents a risk for wildlife in the region. Such results, the authors believe, demonstrate that adequate risk assessments should be undertaken in Turkey and neighbouring countries. (Résumé d'auteur

Simplifying and improving the extraction of nitrate from freshwater for stable isotope analyses

Determining the isotopic composition of nitrate (NO3_) in water can prove useful to identify NO3_ sources and to understand its dynamics in aquatic systems. Among the procedures available, the ‘ionexchange resin method’ involves extracting NO3_ from freshwater and converting it into solid silver nitrate (AgNO3), which is then analysed for 15N/14N and 18O/16O ratios. This study describes a simplified methodology where water was not pre-treated to remove dissolved organic carbon (DOC) or barium cations (added to precipitate O-bearing contaminants), which suited samples with high NO3_ ($400 mM or 25 mg L_1 NO3_) and low DOC (typically <417 mM of C or 5 mg L_1 C) levels. % N analysis revealed that a few AgNO3 samples were of low purity (compared with expected % N of 8.2), highlighting the necessity to introduce quality control/quality assurance procedures for silver nitrate prepared from field water samples. Recommendations are then made to monitor % N together with % O (expected at 28.6, i.e. 3.5 fold % N) in AgNO3 in order to better assess the type and gravity of the contamination as well as to identify potentially unreliable data

A national approach to systematic transboundary aquifer assessment and conceptualisation at relevant scales : a Malawi case study

Study Focus: Integrated water resource management (IWRM) of transboundary aquifers (TBA’s) is becoming increasingly important. Without adequate and accurate scientific knowledge of their extent and characteristics, uninformed policy creation could lead to unsustainable management of these vital resources. This is particularly important within the Southern African Development Community (SADC) where up to 85% of domestic water is supplied by groundwater. In this paper, Malawi is used as a case study to critically evaluate the current transboundary aquifer assessment frameworks within the region and their value in promoting IWRM. A series of illustrative conceptual models of TBA interactions pertinent to the Malawian national border are presented and we consider how TBA assessments may be integrated to national IWRM and strategic policy development. New hydrological insights for the region: Current TBA assessments of Malawi and the wider SADC neglect multiple aspects needed for a national scale management plan. This includes full border TBA system identification alongside, given the geology of the region, consideration of the discontinuous nature of basement complex aquifers and localised alluvial deposits that both result in smaller scale aquifer units. Conceptualising such local scale complexity and encouraging countries to develop a strategy that systematically examines TBA systems along their national border at relevant scales will allow for more focused conjunctive policy creation and sustainable management of TBA’s