Reefcrete:Reducing the environmental footprint of concrete for eco-engineering marine structures

The ecological value of engineered marine structures can be enhanced by building-in additional habitat complexity. Pre-fabricated habitat units can be cheaply and easily cast from concrete into heterogeneous three-dimensional shapes and surface topographies, with proven ability to enhance biodiversity on artificial structures. The net ecological benefits of enhancement using concrete, however, may be compromised on account of its large environmental footprint and poor performance as substrate for many marine organisms. We carried out a pilot study to trial alternative cast-able “Reefcrete” concrete mixes, with reduced environmental footprints, for use in the marine environment. We used partial replacement of Portland cement with recycled ground granulated blast-furnace slag (GGBS), and partial replacement of coarse aggregate with hemp fibres and recycled shell material. We calculated the estimated carbon footprint of each concrete blend and deployed replicate tiles in the intertidal environment for 12 months to assess their performance as substrate for marine biodiversity. The hemp and shell concrete blends had reduced carbon footprints compared to both ordinary Portland cement based concrete and the GGBS based control concrete used in this study. At the end of the experiment, the hemp and shell blends supported significantly more live cover than the standard GGBS control blend. Taxon richness, particularly of mobile fauna, was also higher on the hemp concrete than either the shell or GGBS control. Furthermore, the overall species pool recorded on the hemp concrete was much larger. Community compositions differed significantly on the hemp tiles, compared to GGBS controls. This was largely explained by higher abundances of several taxa, including canopy-forming algae, which may have facilitated other taxa. Our findings indicate that the alternative materials trialled in this study provided substrate of equal or better habitat suitability compared to ordinary GGBS based concrete. Given the growing interest in ecological engineering of marine infrastructure, we propose there would be great benefit in further development of these alternative “Reefcrete” materials for wider application

Nudus amor formam non amat artificem : representations of gender in elegiac discourse

This thesis explores the representation of gender, desire, and identity in elegiac discourse. It does so through the lens of post‐structural and psychoanalytic theory, referring to the works of Michel Foucault, Judith Butler, Jessica Benjamin, and Laura Mulvey in their analyses of power, gender performativity, and subjectivity. Within this thesis, these concepts are applied primarily to the works of Tibullus, Propertius, and Sulpicia, ultimately demonstrating that the three love elegists seek, in their poetry, to construct subversive discourses which destabilise the categories by which gender and identity were determined in Augustan Rome. This discussion is supplemented by the investigation of Ovid’s use of elegiac discourse in Book 10 of his Metamorphoses, and the way in which it both comments upon Augustan love elegy and demonstrates a number of parallels with its thematic content. This thesis focuses especially on the representation of power relations within elegiac discourse, the various levels on which such relations operate and, finally, the possibilities for the contestation of and resistance to power, in addition to the motivations that might lie behind the poet‐lover’s frequent attraction and submission to it

Stakeholder priorities for multi-functional coastal defence developments and steps to effective implementation

To fulfil international conservation commitments, governments have begun to recognise the need for more proactive marine planning policies, advocating sensitive engineering design that can deliver secondary benefits above and beyond the primary purpose of developments. In response, there is growing scientific interest in novel multi-functional coastal defence structures with built-in secondary ecological and/or socio-economic benefits. To ensure research efforts are invested effectively, it is first necessary to determine what secondary benefits can potentially be built-in to engineered coastal defence structures, and further, which of these benefits would be most desirable. It is unlikely that secondary benefits are perceived in the same way across different stakeholder groups. Further, their order of priority when evaluating different options is unlikely to be consistent, since each option will present a suite of compromises and trade-offs. The aim of this study was to investigate stakeholder attitudes towards multi-functional coastal defence developments across different sector groups. A preliminary questionnaire indicated unanimous support for implementing multi-functional structures in place of traditional single-purpose ones. This preliminary survey informed the design of a Delphi-like study, which revealed a more nuanced and caveated level of support from a panel of experts and practitioners. The study also elicited a degree of consensus that the most desirable secondary benefits that could be built-in to developments would be ecological ones – prioritised over social, economic and technical benefits. This paper synthesises these findings, discusses the perceived barriers that remain, and proposes a stepwise approach to effective implementation of multi-functional coastal defence developments

Light as a chronobiologic countermeasure for long-duration space operations

Long-duration space missions require adaptation to work-rest schedules which are substantially shifted with respect to earth. Astronauts are expected to work in two-shift operations and the environmental synchronizers (zeitgebers) in a spacecraft differ significantly from those on earth. A study on circadian rhythms, sleep, and performance was conducted by exposing four subjects to 6 deg head-down tilt bedrest (to simulate the effects of the weightless condition) and imposing a 12-h shift (6 h delay per day for two days). Bright light was tested in a cross-over design as a countermeasure for achieving faster resynchronization and regaining stable conditions for sleep and circadian rhythmicity. Data collection included objective sleep recording, temperature, heart rate, and excretion of hormones and electrolytes as well as performance and responses to questionnaires. Even without a shift in the sleep-wake cycle, the sleep quantity, circadian amplitudes and 24 h means decreased in many functions under bedrest conditions. During the shift days, sleepiness and fatigue increased, and alertness decreased. However, sleep quantity was regained, and resynchronization was completed within seven days after the shift for almost all functions, irrespective of whether light was administered during day-time or night-time hours. The time of day of light exposure surprisingly appeared not to have a discriminatory effect on the resynchronization speed under shift and bedrest conditions. The results indicate that simulated weightlessness alters circadian rhythms and sleep, and that schedule changes induce additional physiological disruption with decreased subjective alertness and increased fatigue. Because of their operational implications, these phenomena deserve additional investigation

Wheat NAC transcription factor <i>NAC5‐1</i> is a positive regulator of senescence

Wheat (Triticum aestivum L.) is an important source of both calories and protein in global diets, but there is a trade‐off between grain yield and protein content. The timing of leaf senescence could mediate this trade‐off as it is associated with both declines in photosynthesis and nitrogen remobilization from leaves to grain. NAC transcription factors play key roles in regulating senescence timing. In rice, OsNAC5 expression is correlated with increased protein content and upregulated in senescing leaves, but the role of the wheat ortholog in senescence had not been characterized. We verified that NAC5‐1 is the ortholog of OsNAC5 and that it is expressed in senescing flag leaves in wheat. To characterize NAC5‐1, we combined missense mutations in NAC5‐A1 and NAC5‐B1 from a TILLING mutant population and overexpressed NAC5‐A1 in wheat. Mutation in NAC5‐1 was associated with delayed onset of flag leaf senescence, while overexpression of NAC5‐A1 was associated with slightly earlier onset of leaf senescence. DAP‐seq was performed to locate transcription factor binding sites of NAC5‐1. Analysis of DAP‐seq and comparison with other studies identified putative downstream target genes of NAC5‐1 which could be associated with senescence. This work showed that NAC5‐1 is a positive transcriptional regulator of leaf senescence in wheat. Further research is needed to test the effect of NAC5‐1 on yield and protein content in field trials, to assess the potential to exploit this senescence regulator to develop high‐yielding wheat while maintaining grain protein content

Wheat NAC transcription factor <i>NAC5‐1</i> is a positive regulator of senescence

Wheat (Triticum aestivum L.) is an important source of both calories and protein in global diets, but there is a trade‐off between grain yield and protein content. The timing of leaf senescence could mediate this trade‐off as it is associated with both declines in photosynthesis and nitrogen remobilization from leaves to grain. NAC transcription factors play key roles in regulating senescence timing. In rice, OsNAC5 expression is correlated with increased protein content and upregulated in senescing leaves, but the role of the wheat ortholog in senescence had not been characterized. We verified that NAC5‐1 is the ortholog of OsNAC5 and that it is expressed in senescing flag leaves in wheat. To characterize NAC5‐1, we combined missense mutations in NAC5‐A1 and NAC5‐B1 from a TILLING mutant population and overexpressed NAC5‐A1 in wheat. Mutation in NAC5‐1 was associated with delayed onset of flag leaf senescence, while overexpression of NAC5‐A1 was associated with slightly earlier onset of leaf senescence. DAP‐seq was performed to locate transcription factor binding sites of NAC5‐1. Analysis of DAP‐seq and comparison with other studies identified putative downstream target genes of NAC5‐1 which could be associated with senescence. This work showed that NAC5‐1 is a positive transcriptional regulator of leaf senescence in wheat. Further research is needed to test the effect of NAC5‐1 on yield and protein content in field trials, to assess the potential to exploit this senescence regulator to develop high‐yielding wheat while maintaining grain protein content

Fat4-Dchs1 signalling controls cell proliferation in developing vertebrae

The protocadherins Fat4 and Dchs1 act as a receptor-ligand pair to regulate many developmental processes in mice and humans, including development of the vertebrae. Based on conservation of function between Drosophila and mammals, Fat4-Dchs1 signalling has been proposed to regulate planar cell polarity (PCP) and activity of the Hippo effectors Yap and Taz, which regulate cell proliferation, survival and differentiation. There is strong evidence for Fat regulation of PCP in mammals but the link with the Hippo pathway is unclear. In Fat4(−/−) and Dchs1(−/−) mice, many vertebrae are split along the midline and fused across the anterior-posterior axis, suggesting that these defects might arise due to altered cell polarity and/or changes in cell proliferation/differentiation. We show that the somite and sclerotome are specified appropriately, the transcriptional network that drives early chondrogenesis is intact, and that cell polarity within the sclerotome is unperturbed. We find that the key defect in Fat4 and Dchs1 mutant mice is decreased proliferation in the early sclerotome. This results in fewer chondrogenic cells within the developing vertebral body, which fail to condense appropriately along the midline. Analysis of Fat4;Yap and Fat4;Taz double mutants, and expression of their transcriptional target Ctgf, indicates that Fat4-Dchs1 regulates vertebral development independently of Yap and Taz. Thus, we have identified a new pathway crucial for the development of the vertebrae and our data indicate that novel mechanisms of Fat4-Dchs1 signalling have evolved to control cell proliferation within the developing vertebrae

Bridging the conservation and development trade‐off? A working landscape critique of a conservancy in the Maasai Mara

The recent call to halt biodiversity loss by protecting half the planet has been hotly contested because of the extent to which people might be excluded from these landscapes. It is clear that incorporating landscapes that implicitly work for indigenous people is vital to achieving any sustainable targets. We examine an attempt to balance the trade‐offs between conservation and development in Enonkishu Conservancy in the Maasai Mara, using a working landscape approach. Mobile livestock production strategies are theoretically consistent with wildlife‐based activities and can present a win‐win solution for both conservation and development. We explore the success and failings of Enonkishu's evolving attempts to achieve this: addressing the criticism of the conservation sector that it fails to learn from its mistakes. We found that Enonkishu has had considerable positive conservation outcomes, preventing the continued encroachment of farmland and maintaining and improving rangeland health relative to the surrounding area, while maintaining diverse and large populations of wildlife and livestock. The learning from certain ventures that failed, particularly on livestock, has created institutions and governance that, while still evolving, are more robust and relevant for conservancy members, by being fluid and inclusive. Practical implication: Diverse revenue streams (beyond tourism, including a residential estate, livestock venture and philanthropy) enabled Enonkishu to withstand the pressures of COVID‐19. Livestock is crucial for defining the vision of the conservancy, and the institutions and governance that underpin it