Identification and removal of Mn-Mg-rich contaminant phases in foraminiferal tests: Implications for Mg/Ca past temperature reconstructions

The geochemical composition of foraminifera shells from an Ocean Drilling Program site in the Panama Basin has been analyzed by several analytical techniques (LA-ICP-MS, ICP-MS, XRD, SEM, EDX) in order to identify and evaluate the occurrence of contaminant phases which may bias paleoenvironmental reconstructions. LA-ICP-MS results on uncleaned tests indicate the presence of Mn-Mg-rich contaminant phases at the inner surfaces of the foraminiferal shells (which have Mn/Ca ratios up to 400 mmol mol-1 and Mg/Ca ratios up to 50 mmol mol-1). We have rigorously assessed the ability of different cleaning protocols to remove these contaminant phases and have obtained satisfactory results only when a reductive step is included. The analysis of cleaning residuals collected after each of the different cleaning steps applied reveals that high Mn values are associated with at least two different contaminant phases, of which only one is linked to high Mg values. XRD analysis further reveals that the Mn-Mg-rich phase is the Ca-Mn-Mg carbonate kutnahorite (Ca(Mn, Mg)(CO3)2). Our results demonstrate that the presence of kutnahorite-like minerals can bias Mg/Ca ratios toward higher values (by 7-36%) and lead to significant overestimation of past seawater temperatures (by 0.9 up to 6.2°C, in the case of these Panama Basin samples)

"Poof! a'm heppily saving the Lord...": multimodality and evaluative discourses in male toilet graffiti at the University of the Western Cape

This paper explores the use of punctuation, capitalisation, linguistic forms and images in the construction of evaluative discourses in male toilet graffiti at the University of the Western Cape. Of particular interest is how male students use these devises in the discursive construction of the appraisal resource of Attitude, Graduation and Evaluation. Using over 150 tokens of graffiti, the paper uses a multimodal approach employing notions of resemiotisation and remediation to show how taboo language, font size, images and sketches are repurposed to aid the evaluation of the 'self' and the 'other' in toilet graffiti. The paper shows that through utilising multimodal texts, graffiti writers are able to reformulate and situate novel meanings in contexts; and in terms of appraisal, the verbal and non-verbal semiotic material are strategically combined to engender novel evaluations

Power and knowledge-building in teacher inquiry: negotiating interpersonal and ideational difference

Professional collaboration in schools features prominently in contemporary approaches to educational change. Advocates highlight the importance of situated knowledge to continuous teacher learning, sustained school reform and improved student learning. Critics portray collaboration as an invisible and coercive means of official control. The framework presented in this paper aims to treat these perspectives not as ideological positions but as starting points for empirical investigation into the dynamics of power in professional collaboration. The framework draws on social semiotic theories of language and functional linguistics to portray the ways in which the development of ideas and the development of social relations ideational and interpersonal meaning move in concert. Excerpts from an in-depth study of interaction among science teachers and teacher-leaders in a secondary school undergoing broad reform illustrate the application of this framework. Attention to the dynamics of support and challenge in the most generative of these interactions reveals distinctive patterns of the negotiation of interpersonal and ideational meaning. These patterns of control provide a means of connecting the microprocesses of building knowledge with the broader dynamics of power at play in educational change

Using exchange structure analysis to explore argument in text-based computer conferences

Computer conferencing provides a new site for students to develop and rehearse argumentation skills, but much remains to be learnt about how to encourage and support students in this environment. Asynchronous text-based discussion differs in significant ways from face-to-face discussion, creating a need for specially designed schemes for analysis. This paper discusses some of the problems of analysing asynchronous argumentation, and puts forward an analytical framework based on exchange structure analysis, which brings a linguistic perspective to bear on the interaction. Key features of the framework are attention to both interactive and ideational aspects of the discussion, and the ability to track the dynamic construction of argument content. The paper outlines the framework itself, and discusses some of the findings afforded by this type of analysis, and its limitations

Positive self-evaluation versus negative other-evaluation in the political genre of pre-election debates.

The present study explores the language of evaluation in a sub-genre of political discourse, pre-electoral debates, and its potential persuasive function for gaining voters via a contraposition of positive self-evaluation and negative evaluation of the other candidate. A further aim of this research is to check whether the candidate¿s ideology has a bearing on the entities that get evaluated. After a brief examination of the characteristics of the sub-genre at hand, specifically in the Spanish context, we present the results of an evaluation analysis carried out in a corpus of 19,849 words, which is the extension of the most recent pre-electoral debate held in Spain between the candidates of the two main political parties. Taking into account Van Dijk¿s CDA framework (2005) for parliamentary debates as global semantic strategies of positive self-presentation and negative other-presentation, Martin and White¿s (2005) method was adopted as an analytical tool. The results showed that, although each candidate had different preferences in the choice of evaluative devices, they both used them as a strategy to win electoral votes while deprecating the opposing party and, therefore, minimizing their chances of winning the elections. On the other hand, and despite their opposing ideology, they both seem to defend those policies that are more widely accepted in order not to risk losing voters: public services and egalitarian social policies

Assessing social responsibility::A quantitative analysis of Appraisal in BP’s and IKEA’s social reports

A growing public awareness of the potential negative impacts of corporate activities on the natural environment and society compels large companies to invest increasing resources in the communication of their responsible conduct. This article employs Appraisal theory in a comparative analysis of BP’s and IKEA’s 2009 social reports, each company’s record of their non-financial performance. The main objective is to explore how, through Appraisal resources, BP and IKEA construct their corporate identity and relationship with their stakeholders. The analysis reveals two markedly different approaches to the construction of a responsible corporate identity. While BP deploys interpersonal resources to portray itself as a trustworthy and authoritative expert, IKEA discloses itself as a sensitive and caring corporation, engaged in a continual effort to improve. These differences are interpreted in light of the legitimization challenges the two companies face

Dating of the hominid (Homo neanderthalensis) remains accumulation from El Sidrón Cave (Piloña, Asturias, North Spain): an example of a multi-methodological approach to the dating of Upper Pleistocene sites.

The age of Neanderthal remains and associated sediments from El Sidrón cave has been obtained through different dating methods (14CAMS, U/TH, OSL, ESR and AAR) and samples (charcoal debris, bone, tooth dentine, stalagmitic flowstone, carbonate-rich sediments, sedi- mentary quartz grains, tooth enamel and land snail shells). Detrital Th contamination ren- dered Th/U dating analyses of flowstone unreliable. Recent 14C contamination produced spurious age-values from charcoal samples as well as from inadequately pretreated tooth samples. Most consistent 14C dates are grouped into two series: one between 35 and 40 ka and the other between 48 and 49 ka. Most ESR and AAR samples yielded concordant ages, ranging between 39 and 45 ka; OSL dating results permitted adequate bracketing of the sedimentary layer that contained the human remains. Our results emphasize the value of multi-dating approaches for the establishment of reliable chronologies of human remains

Transitioning global change experiments on Southern Ocean phytoplankton from lab to field settings: insights and challenges

The influence of global change on Southern Ocean productivity will have major ramifications for future management of polar life. A prior laboratory study investigated the response of a batch-cultured subantarctic diatom to projected change simulating conditions for 2100 (increased temperature/CO2/irradiance/iron; decreased macronutrients), showed a twofold higher chlorophyll-derived growth rate driven mainly by temperature and iron. We translated this design to the field to understand the phytoplankton community response, within a subantarctic foodweb, to 2100 conditions. A 7-d shipboard study utilizing 250-liter mesocosms was conducted in March 2016. The outcome mirrors lab-culture experiments, yielding twofold higher chlorophyll in the 2100 treatment relative to the control. This trend was also evident for intrinsic metrics including nutrient depletion. Unlike the lab-culture study, photosynthetic competence revealed a transient effect in the 2100 mesocosm, peaking on day 3 then declining. Metaproteomics revealed significant differences in protein profiles between treatments by day 7. The control proteome was enriched for photosynthetic processes (c.f. 2100) and exhibited iron-limitation signatures; the 2100 proteome exposed a shift in cellular energy production. Our findings of enhanced phytoplankton growth are comparable to model simulations, but underlying mechanisms (temperature, iron, and/or light) differ between experiments and models. Batch-culture approaches hinder cross-comparison of mesocosm findings to model simulations (the latter are akin to “continuous-culture chemostats”). However, chemostat techniques are problematic to use with mesocosms, as mesozooplankton will evade seawater flow-through, thereby accumulating. Thus, laboratory, field, and modeling approaches reveal challenges to be addressed to better understand how global change will alter Southern Ocean productivity

Relationship building in Vietnamese English written business communication: A systemic functional analysis,

English has a long history in Vietnam and in the last two decades, particularly for business communication, it has developed with an unprecedented speed. Despite this ascendancy, there is an absence of research regarding English in Vietnamese business correspondence. The current study is an in-depth investigation of this with a particular focus on the written features of English, reflecting the importance of written documents in this context. This research was framed within the theoretical perspectives of Systemic Functional Linguistics (SFL). 303 business texts from various business sectors composed by Vietnamese writers were collected. They were then analysed with regard to four SFL variables: speech functions, mood, modality and terms of address to establish the nature of the interpersonal written features developing within Vietnam. The findings of the study indicate that the writers employed several linguistic strategies (e.g., using Vietnamese kinship terms and Vietnamese lexis) and non-linguistic strategies (e.g., using emoticons and written giggling) to establish a close relationship with their interactants. Relationship building was also reflected in the employment of politeness strategies to achieve positive politeness effect. These results suggest that SFL is a useful theoretical framework and analytical tool to uncover how English is employed in different socio-cultural contexts to enact social meaning-making processes