A new model for the formation of microbial polygons in a coastal sabkha setting

The stratigraphic record of microbially induced sedimentary structures spans most of the depositional record. Today, microbes continue to generate, bind and modify sediments in a vast range of depositional environments. One of the most cited of these settings is the coastal microbial mat system of the Persian/Arabian Gulf. In this setting, an extensive zone of microbial mat polygons has previously been interpreted as resulting from desiccation‐related contraction during episodic drying. This study employs 15 years of field‐based monitoring of the interaction between environmental factors and the development and evolution of polygon morphologies to test the desiccation model in this setting. On the basis of these observations, a new model is proposed that accounts for the genesis and development of microbial polygons without the need for desiccation‐induced shrinkage. Conversely, the formation, development and erosion of microbial polygons is a direct result of the production of large amounts of organic matter in a healthy, yet spatially limited, microbial community. The recognition of microbial polygons has previously been applied as a diagnostic tool for the reconstruction of ancient depositional environments. The present study calls these interpretations into doubt. It is inferred that preservation of the microbial polygons as a recognizable form would be rare. Biological degradation and compaction will reduce polygons to produce the ‘wispy’ laminae that are a common feature of ancient sabkha lithofacies

Quantifying performance of ultrasonic immersion inspection using phased arrays for curvilinear disc forgings

Use of full-matrix capture (FMC), combined with the total focusing method (TFM), has been shown to provide improvements to flaw sensitivity within components of irregular geometry. Ultrasonic immersion inspection of aerospace discs requires strict specifications to ensure full coverage – one of which is that all surfaces should be machined flat. The ability to detect defects through curved surfaces, with an equivalent sensitivity to that obtained through flat surfaces could bring many advantages. In this work, the relationship between surface curvature and sensitivity to standard defects was quantified for various front wall radii. Phased array FMC immersion inspection of curved components was simulated using finite element modelling, then visualized using surface-compensated focusing techniques. This includes the use of BRAIN software developed at the University of Bristol for production of TFM images. Modelling results were compared to experimental data from a series of test blocks with a range of curvatures, containing standard defects. The sensitivity to defects is evaluated by comparing the performance to conventional methods. Results are used to highlight the benefits and limitations of these methods relating to the application area of aerospace engine disc forgings

The AEW Project: Professional Development for Teacher Aides in Remote Indigenous Communities

The purpose of this paper is to give a conceptual account of an approach which seeks to advance the professionalization of the Aboriginal Education Workers (AEW) and Teacher Aides (TA) in remote communities in Australia. We set out the current situation where the training and support offered to the AEW/TA is such that their potential to make a contribution to the education of Indigenous children is either underdeveloped or inaccessible. We then describe the roll out of a specifically designed set of modules that form part of a novel approach to the professional development of the AEW/TA, and go on to analyse the lessons that may be learned from early phases of the project. Our analysis draws upon Critical Realist theory (Bhaskar, 2016), the work of the media theorist Hans Magnus Enzensberger and Charles Leadbeater’s (2014) use of the concept of a cultural commons, and the emerging literature on frugal and inclusive innovation (George, McGahan, & Prabhu, 2012; Radjou, Prabhu, & Ahuja, 2012; Tiwari & Herstatt, 2012)

Item 1. Apologies

Apologies were received from Stephen Burt & Dave Bullock. Item 2. Agreement of agenda The agenda was agreed. Item 3. Minutes of last meeting The minutes of the committee meeting & AGM held on 12 th September 2014 were agreed as being correct. Item 4. Items arising Actions from the previous committee meeting were considered and the following matters were discussed: Rain gauge raffle – At the 2013 RMetS Amateur Meteorologist Symposium, MD organised a SIG stand where he raffled an EML rain gauge, signed-up 29 new members & raised £145. MD was thanked for his hard work. New committee member – MD has contacted, but not yet had a reply from, Mark Wilkinson (James Hutton Institute, Aberdeen) to invite him to join the SIG committee. The SIG has offered to pay travel expenses for Mark for one trip/year to attend a SI

Erosion‐initiated stromatolite and thrombolite formation in a present‐day coastal sabkha setting

Laminated microbial mats and microbialites have been documented from a variety of coastal marine environments. This study aims to provide the first detailed descriptions of intertidal pools, along with their hosted thrombolite and stromatolite structures, from Abu Dhabi, and to propose a model for their formation and evolution. It is proposed that the development of pools within the upper intertidal zone was initiated by localized erosion of the laminated microbial mats during high energy events. The removal of the protective mats permitted erosion of the underlying unconsolidated sediment to produce erosional scours that continued to develop to create the pools observed today. The margins of the newly‐created submerged environment were colonized by a cyanobacteria dominated microbial community. The precipitation of aragonite cement, associated with the cyanobacteria, stabilized the pool walls and cemented the microbial communities to form stromatolitic and thrombolitic fabrics. Syndepositional cementation was further enhanced by the precipitation of marine cements as a result of evaporation‐driven Ca2+ and Mg2+ supersaturation. Erosion behind and below the cemented pool wall eventually resulted in rim‐collapse and the formation of the observed pool margin parallel thrombolite bands. Successive generations of lithification and erosion increased the area of the pool with the earliest thrombolites eroding and becoming increasingly isolated. In summary, the resultant microbialites developed through the complex interplay of erosion, abiotic early lithification and microbially‐mediated processes, and represent a continuum between unlithified laminated microbial mats and domal microbialites. These features are most likely produced during a sea‐level scenario of stillstand or transgression and, as such, may be useful as a diagnostic tool to elucidate the onset of transgression. The newly proposed model for stromatolite formation has significant implications for the recognition and interpretation of similar structures observed in the fossil record

'Getting people on board': Discursive leadership for consensus building in team meetings

Meetings are increasingly seen as sites where organizing and strategic change take place, but the role of specific discursive strategies and related linguistic-pragmatic and argumentative devices, employed by meeting chairs, is little understood. The purpose of this article is to address the range of behaviours of chairs in business organizations by comparing strategies employed by the same chief executive officer (CEO) in two key meeting genres: regular management team meetings and ‘away-days’. While drawing on research from organization studies on the role of leadership in meetings and studies of language in the workplace from (socio)linguistics and discourse studies, we abductively identified five salient discursive strategies which meeting chairs employ in driving decision making: (1) Bonding; (2) Encouraging; (3) Directing; (4) Modulating; and (5) Re/Committing. We investigate the leadership styles of the CEO in both meeting genres via a multi-level approach using empirical data drawn from meetings of a single management team in a multinational defence corporation. Our key findings are, first, that the chair of the meetings (and leading manager) influences the outcome of the meetings in both negative and positive ways, through the choice of discursive strategies. Second, it becomes apparent that the specific context and related meeting genre mediate participation and the ability of the chair to control interactions within the team. Third, a more hierarchical authoritarian or a more interpersonal egalitarian leadership style can be identified via specific combinations of these five discursive strategies. The article concludes that the egalitarian leadership style increases the likelihood of achieving a durable consensus. Several related avenues for research are outlined