Silicon, the silver bullet for mitigating biotic and abiotic stress, and improving grain quality, in rice?

Adequate silicon fertilization greatly boosts rice yield and mitigates biotic and abiotic stress, and improves grain quality through lowering the content of cadmium and inorganic arsenic. This review on silicon dynamics in rice considers recent advances in our understanding of the role of silicon in rice, and the challenges of maintaining adequate silicon fertility within rice paddy systems. Silicon is increasingly considered as an element required for optimal plant performance, particularly in rice. Plants can survive with very low silicon under laboratory/glasshouse conditions, but this is highly artificial and, thus, silicon can be considered as essential for proper plant function in its environment. Silicon is incorporated into structural components of rice cell walls were it increases cell and tissue rigidity in the plant. Structural silicon provides physical protection to plants against microbial infection and insect attack as well as reducing the quality of the tissue to the predating organisms. The abiotic benefits are due to silicon's effect on overall organ strength. This helps protect against lodging, drought stress, high temperature (through efficient maintenance of transpiration), and photosynthesis by protecting against high UV. Furthermore, silicon also protects the plant from saline stress and against a range of toxic metal stresses (arsenic, cadmium, chromium, copper, nickel and zinc). Added to this, silicon application decreases grain concentrations of various human carcinogens, in particular arsenic, antimony and cadmium. As rice is efficient at stripping bioavailable silicon from the soil, recycling of silicon rich rice straw biomass or addition of inorganic silicon fertilizer, primarily obtained from iron and steel slag, needs careful management. Silicon in the soil may be lost if the silicon-cycle, traditionally achieved via composting of rice straw and returning it to the land, is being broken. As composting of rice straw and incorporation of composted or non-composted straw back to land are resource intensive activities, these activities are declining due to population shifts from the countryside to cities. Processes that accelerate rice straw composting, therefore, need to be identified to aid more efficient use of this resource. In addition, rice genetics may help address declining available silicon in paddy soils: for example by selecting for characteristics during breeding that lead to an increased ability of roots to access recalcitrant silicon sources from soil and/or via selection for traits that aid the maintenance of a high silicon status in shoots. Recent advances in understanding the genetic regulation of silicon uptake and transport by rice plants will aid these goals.

Response of soil microbial communities to single and multiple doses of an organic pollutant

The effect of 100 μg 1,2-dichlorobenzene (1,2-DCB) g^-1 dry weight (dw) of soil introduced either as a single dose or multiple (10 fortnightly) doses of 10 μg g^-1 dw, on the microbial biomass, diversity of culturable bacterial community and the rate of 1,2-DCB mineralisation, were compared. After 22 weeks exposure both application regimes significantly reduced total bacterial counts and viable fungal hyphal length. The single dose had the greatest overall inhibitory effect, although the extent of inhibition varied throughout the study. Total culturable bacterial counts, determined after 22 weeks exposure showed little response to 1,2-DCB, but pseudomonad counts in single and multiple treatments were reduced to 9.7 and 0.147%, respectively, of the numbers detected in the control soil. The effect of 1,2-DCB application on the taxonomic composition of the culturable bacteria community was determined by fatty acid methyl ester (FAME) analysis. Compared to control soils, the single dose treatment had a lower percentage of Arthrobacter and Micrococcus. Multiple applications had a significant effect upon pseudomonad abundance, which represented only 2% of the identified community, compared to 45.6% in the control. The multi-dosed soils contained a high percentage of bacilli (> 25%). The effects of 1,2-DCB applications on the metabolic potential of the soil microbial community was determined by BIOLOG profiling. The number of carbon compounds utilised by the community in the multi-dosed soils (49 positives) was significantly less (P < 0.05) than detected in the single dose treatment (76) and control (66). The rate of 1,2-DCB mineralisation, determined by ¹⁴CO₂ production from radiolabelled [UL-¹⁴C] 1,2-DCB, declined throughout the study, and after 22 weeks was slightly but significantly (P < 0.05) lower in the multiply- than the singly-dosed soils. The differential response to 1,2-DCB treatments was attributed to its reduced bioavailability in soils after a single exposure, compared to multiple applications.

Interchange of entire communities: microbial community coalescence

Microbial communities are enigmatically diverse. We propose a novel view of processes likely affecting microbial assemblages, which could be viewed as the Great American Interchange en miniature: the wholesale exchange among microbial communities resulting from moving pieces of the environment containing entire assemblages. Incidental evidence for such ‘community coalescence’ is accumulating, but such processes are rarely studied, likely because of the absence of suitable terminology or a conceptual framework. We provide the nucleus for such a conceptual foundation for the study of community coalescence, examining factors shaping these events, links to bodies of ecological theory, and we suggest modeling approaches for understanding coalescent communities. We argue for the systematic study of community coalescence because of important functional and applied consequences.

Ecological communities are vulnerable to realistic extinction sequences

Loss of species will directly change the structure and potentially the dynamics of ecological communities, which in turn may lead to additional species loss (secondary extinctions) due to direct and/or indirect effects (e.g. loss of resources or altered population dynamics). Furthermore, the vulnerability of food webs to repeated species loss is expected to be affected by food web topology, species interactions, as well as the order in which species go extinct. Species traits such as body size, abundance and connectivity might determine a species' vulnerability to extinction and, thus, the order in which species go primarily extinct. Yet, the sequence of primary extinctions, and their effects on the vulnerability of food webs to secondary extinctions, when species abundances are allowed to respond dynamically, has only recently become the focus of attention. Here, we analyse and compare topological and dynamical robustness to secondary extinctions of model food webs, in the face of 34 extinction sequences based on species traits. Although secondary extinctions are frequent in the dynamical approach and rare in the topological approach, topological and dynamical robustness tends to be correlated for many bottom-up directed, but not for top-down directed deletion sequences. Furthermore, removing species based on traits that are strongly positively correlated to the trophic position of species (such as large body size, low abundance, high net effect) is, under the dynamical approach, found to be as destructive as removing primary producers. Such top-down oriented removal of species are often considered to correspond to realistic extinction scenarios, but earlier studies, based on topological approaches, have found such extinction sequences to have only moderate effects on the remaining community. Thus, our result suggests that the structure of ecological communities, and therefore the integrity of important ecosystem processes could be more vulnerable to realistic extinction sequences than previously believed.

Rural communities and wind farms: a contingent valuation investigation

Using the contingent valuation method, this study investigates the preferences of local people for a wind farm that is planned in the Province of Rome. We estimate the reductions in their bimonthly electrical bills over a period of time that respondents are willing to accept as compensation for the installation of the wind farm. Our results suggest that respondents who perceive that the wind farm generates substantial negative impacts on landscape beauty ask higher reductions than others, while respondents who believe that the wind farm produces economic benefits for local communities ask lower reductions than others. Finally, we find that the demand for compensative measures is influenced particularly by socio-economic factors such as age and education.

Assessing the impact of shore-based shellfish collection on under-boulder communities in Strangford Lough.

Under-boulder communities are listed as a priority habitat as they provide shelter, shade and moisture and play an important role in the life-cycle of many marine algae and animals.

Think, code, succeed: The Programming Studio as a games-based collaboration:Paper published in the Proceedings of the Association for Teacher Education in Europe conference: Teacher Education through Partnerships and Collaborative Learning Communities, Glasgow, UK. ATEE, 2015

This paper investigates the profile of teachers in the island of Ireland who declared themselves willing to undertake professional development activities in programming, in particular to master programming by taking on-line courses involving the design of computer games. Using the Technology Acceptance Model (TAM), it compares scores for teachers “willing” to undertake the courses with scores for those who declined, and examines other differences between the groups of respondents. Findings reflect the perceived difficulties of programming and the current low status accorded to the subject in Ireland. The paper also reviews the use of games-based learning as a “hook” to engage learners in programming and discusses the role of gamification as a tool for motivating learners in an on-line course. The on-line course focusing on games design was met with enthusiasm, and there was general consensus that gamification was appropriate for motivating learners in structured courses such as those provided.

Abundance and diversity of sedimentary bacterial communities in a coastal productive setting in the Western Irish Sea

The bacterial community composition and biomass abundance from a depositional mud belt in the western Irish Sea and regional sands were investigated by phospholipid ester-linked fatty acid profiling, denaturing gradient gel electrophoresis and barcoded pyrosequencing of 16S rRNA genes. The study area varied by water depth (12-111 m), organic carbon content (0.09-1.57% TOC), grain size, hydrographic regime (well-mixed vs. stratified), and water column phytodetrital input (represented by algal polyunsaturated PLFA). The relative abundance of bacterial-derived PLFA (sum of methyl-branched, cyclopropyl and odd-carbon number PLFA) was positively correlated with fine-grained sediment, and was highest in the depositional mud belt. A strong association between bacterial biomass and eukaryote primary production was suggested based on observed positive correlations with total nitrogen and algal polyunsaturated fatty acids. In addition, 16S rRNA genes affiliated to the classes Clostridia and Flavobacteria represented a major proportion of total 16S rRNA gene sequences. This suggests that benthic bacterial communities are also important degraders of phytodetrital organic matter and closely coupled to water column productivity in the western Irish Sea.

Negotiating Territoriality and Diversity: Young People’s Encounters in Northern Ireland Divided Communities

Neighborhoods across the globe are becoming increasingly ‘divers’, yet we still find their urban encounters reproduced through negotiating differences that escalates moods of social inequality and spatial imbalances. Research on ethnic division also stresses the spatial aspects of their production as shared urban spaces are mostly signified in the literature as ethnic ‘enclaves’. Territoriality and place attachment, in this sense, has a wide impact on the people’s everyday encounters while experiencing segregation. These historical narratives have produced communities that exhibit high levels of intracommunity relations and localized networking. This article investigates how youngster generations in Northern Ireland perceive, accept and respond to their differences, or perhaps how they act against it, to push the boundaries towards more diversity. In fact, the spatial and temporal encounters that occur among one community and the ‘Other’ signify a sort of negotiations and being more constructive about the future. The argument maintains that territoriality and place attachment has a wide impact on the young people’s everyday experiences. The empirical study shows how individuals and community groups position and identify themselves under the impact of social segregation. Building on social identity theories, I explain how people in Derry have established their own sense of belonging, of who they are, based on their group memberships which eventually became an important source of pride and self-esteem.

Social Ecological Constraints to Park Use in Communities with Quality Access

Evidence correlates physical activity, psychological restoration, and social health to proximity to parks and sites of recreation. The purpose of this study was to identify perceived constraints to park use in low-income communities facing significant health disparities, with access to underutilized parks. We used a series of focus groups with families, teens, and older adults in neighborhoods with similar demographic distribution and access to parks over 125 acres in size. Constraints to park use varied across age groups as well as across social ecological levels, with perceived constraints to individuals, user groups, communities, and society. Policies and interventions aimed at increasing park use must specifically address barriers across social ecological levels to be successful.

How do clinicians become teachers? A communities of practice perspective.

There is widespread acceptance that clinical educators should be trained to teach, but faculty development for clinicians is undermined by poor attendance and inadequate learning transfer. As a result there has been growing interest in situating teacher development initiatives in clinical workplaces. The relationship between becoming a teacher and clinical workplace contexts is under theorised. In response, this qualitative research set out to explore how clinicians become teachers in relation to clinical communities and institutions. Using communities of practice (CoP) as a conceptual framework this research employed the sensitising concepts of regimes of competence and vertical (managerial) and horizontal (professional) planes of accountability to elucidate structural influences on teacher development. Fourteen hospital physicians completed developmental timelines and underwent semi-structured interviews, exploring their development as teachers. Despite having very different developmental pathways, participants’ descriptions of their teacher identities and practice that were remarkably congruent. Two types of CoP occupied the horizontal plane of accountability i.e. clinical teams (Firms) and communities of junior doctors (Fraternities). Participants reproduced teacher identities and practice that were congruent with CoPs’ regimes of competence in order to gain recognition and legitimacy. Participants also constructed their teacher identities in relation to institutions in the vertical plane of accountability (i.e. hospitals and medical schools). Institutions that valued teaching supported the development of teacher identities along institutionally defined lines. Where teaching was less valued, clinicians adapted their teacher identities and practices to suit institutional norms. Becoming a clinical educator entails continually negotiating one’s identity and practice between two potentially conflicting planes of accountability. Clinical CoPs are largely conservative and reproductive of teaching practice whereas accountability to institutions is potentially disruptive of teacher identity and practice.