Tree-mediated methane emissions from tropical and temperate peatlands

Methane production and transport processes in peatlands are fairly well understood, but growing evidence for emission of methane through trees has highlighted the need to revisit methane transport processes. In wetland trees, morphological adaptations such as development of hypertrophied lenticels, aerenchyma and adventitious roots in response to soil anoxia mediates gas transport, transporting both oxygen from the atmosphere to oxygen-deprived roots and soil-produced methane from the root-zone to the atmosphere. Although, tree-mediated methane emissions from temperate tree species have been confirmed, methane emissions from tropical tree species and processes that control tree-mediated methane emissions remain unclear. This study explains the role of trees in transporting soil-produced methane to the atmosphere and uncovers the principal mechanisms of tree-mediated methane emissions. Methane emissions from eight tropical tree species and two temperate tree species were studied in situ. The mechanisms and controls on tree-mediated methane emissions were investigated using three year old common alder (Alnus glutinosa; 50 trees) grown under two artificially controlled water-table positions. Methane fluxes from whole mesocosms, the soil surface and tree stems were measured using static closed chambers. Both temperate and tropical tree species released significant quantities of methane, with tropical trees dominating ecosystem level methane fluxes. In temperate peatlands, both the methane gas transport mechanism and quantity of methane emitted from stems is tree-species dependent. In Alnus glutinosa, no correlations were observed between stomatal behaviour and tree-mediated methane emissions, however, stem methane emissions were positively correlated with both stem lenticel density and dissolved soil methane concentration. In Alnus glutinosa, no emissions were observed from leaf surfaces. The results demonstrate that exclusion of tree-mediated methane emissions from flux measurement campaigns in forested peatlands will lead to an underestimation of ecosystem-wide methane emissions

Gelsolin superfamily proteins: key regulators of cellular functions

Abstract.: Cytoskeletal rearrangement occurs in a variety of cellular processes and involves a wide spectrum of proteins. Among these, the gelsolin superfamily proteins control actin organization by severing filaments, capping filament ends and nucleating actin assembly [1]. Gelsolin is the founding member of this family, which now contains at least another six members: villin, adseverin, capG, advillin, supervillin and flightless I. In addition to their respective role in actin filament remodeling, these proteins have some specific and apparently non-overlapping particular roles in several cellular processes, including cell motility, control of apoptosis and regulation of phagocytosis (summarized in table 1). Evidence suggests that proteins belonging to the gelsolin superfamily may be involved in other processes, including gene expression regulation. This review will focus on some of the known functions of the gelsolin superfamily proteins, thus providing a basis for reflection on other possible and as yet incompletely understood roles for these protein

The Impact of Simulated Sulfate Deposition on Peatland Testate Amoebae

Peatlands subjected to sulfate deposition have been shown to produce less methane, believed to be due to competitive exclusion of methanogenic archaea by sulfate-reducing bacteria. Here, we address whether sulfate deposition produces impacts on a higher microbial group, the testate amoebae. Sodium sulfate was applied to experimental plots on a Scottish peatland and samples extracted after a period of more than 10 years. Impacts on testate amoebae were tested using redundancy analysis and Mann-Whitney tests. Results showed statistically significant impacts on amoebae communities particularly noted by decreased abundance of Trinema lineare, Corythion dubium, and Euglypha rotunda. As the species most reduced in abundance are all small bacterivores we suggest that our results support the hypothesis of a shift in dominant prokaryotes, although other explanations are possible. Our results demonstrate the sensitivity of peatland microbial communities to sulfate deposition and suggest sulfate may be a potentially important secondary control on testate amoebae communities

On the Mechanical Properties of Graphyne, Graphdiyne, and Other Poly(Phenylacetylene) Networks

This is the author accepted manuscript. The final version is available from Wiley via the DOI in this recordWe simulate, analyse and compare the mechanical properties of a number of molecular sheet-like systems based on fully substituted, penta-substituted, tetra-substituted and tri-substituted poly(phenylacetylene) using static force-field based methods. The networks are modeled in a 3D environment with and without inter-layer interactions in analogy to graphite and graphene respectively. It is shown that by varying the type of substitution and the length of the acetylene chain, one may control the mechanical properties of such systems. In particular, it is shown that poly(phenylacetylene) systems can be specifically designed to exhibit negative Poisson's ratio, and that the stiffness can be controlled in an independent manner from the Poisson's ratios. This is significant as it highlights the fact that such systems can be tailored to exhibit a particular set of mechanical properties.The research work disclosed in this publication is funded by the ENDEAVOUR Scholarship Scheme (Malta). The scholarship may be part-financed by the European Union − European Social Fund (ESF) under Operational Programme II − Cohesion Policy 2014–2020, “Investing in human capital to create more opportunities and promote the well being of society.” JNG acknowledges the support of the University of Malta research grant

On the Compressibility Properties of the Wine-Rack-Like Carbon Allotropes and Related Poly(phenylacetylene) Systems

This is the author accepted manuscript. The final version is available from Wiley via the DOI in this record.Poly(phenylacetylene) sheets that mimic the geometry of a wine-rack-like structure have been predicted to exhibit negative Poisson's ratios off-axis. However, their potential to exhibit negative linear compressibility (NLC) has remained largely unexplored. In this work, the compressibility and other mechanical properties of wine-rack-like poly(phenylacetylene) networks with 1,2,4,5 tetra-substituted phenyls as well as their equivalent with allene or cyclobutadiene centres are simulated to assess their ability to exhibit negative linear compressibility on-axis and off-axis. It is shown that some of these systems can indeed exhibit negative linear compressibility whilst others exhibit a near-zero compressibility. The results are compared to the compressibility properties of other poly(phenylacetylene) networks reported in literature as well as with those predicted from the analytical model for an idealised wine-rack structure deforming through hinging. Results suggest that these mechanical properties are arising from a wine-rack-like mechanism, and there is a good agreement with the theoretical model, especially for systems with longer acetylene chains whose geometry is closer to that of the idealised wine-rack.University of MaltaENDEAVOUR Scholarship Scheme (Malta

Quantifying tropical peatland dissolved organic carbon (DOC) using UV-visible spectroscopy

UV–visible spectroscopy has been shown to be a useful technique for determining dissolved organic carbon (DOC) concentrations. However, at present we are unaware of any studies in the literature that have investigated the suitability of this approach for tropical DOC water samples from any tropical peatlands, although some work has been performed in other tropical environments. We used water samples from two oil palm estates in Sarawak, Malaysia to: i) investigate the suitability of both single and two-wavelength proxies for tropical DOC determination; ii) develop a calibration dataset and set of parameters to calculate DOC concentrations indirectly; iii) provide tropical researchers with guidance on the best spectrophotometric approaches to use in future analyses of DOC. Both single and two-wavelength model approaches performed well with no one model significantly outperforming the other. The predictive ability of the models suggests that UV–visible spectroscopy is both a viable and low cost method for rapidly analyzing DOC in water samples immediately post-collection, which can be important when working at remote field sites with access to only basic laboratory facilities

Self-reported access to health care, communicable diseases, violence and perception of legal status among online transgender identifying sex workers in the UK.

OBJECTIVES: Transgender-identifying sex workers (TGISWs) are among the most vulnerable groups but are rarely the focus of health research. Here we evaluated perceived barriers to healthcare access, risky sexual behaviours and exposure to violence in the United Kingdom (UK), based on a survey of all workers on BirchPlace, the main transgender sex commerce website in the UK. STUDY DESIGN: The study design used in the study is an opt-in text-message 12-item questionnaire. METHODS: Telephone contacts were harvested from BirchPlace's website (n = 592 unique and active numbers). The questionnaire was distributed with Qualtrics software, resulting in 53 responses. RESULTS: Our survey revealed significant reported barriers to healthcare access, exposure to risky sexual behaviours and to physical violence. Many transgender sex workers reportedly did not receive a sexual screening, and 28% engaged in condomless penetrative sex within the preceding six months, and 68% engaged in condomless oral sex. 17% responded that they felt unable to access health care they believed medically necessary. Half of the participants suggested their quality of life would be improved by law reform. CONCLUSIONS: TGISWs report experiencing a high level of risky sexual behaviour, physical violence and inadequate healthcare access. Despite a National Health System, additional outreach may be needed to ensure access to services by this population.ECD

Review. Molecular and genetic characterisation of the hostprotective oncosphere antigens of taeniid cestode parasites

Abstract Highly effective recombinant vaccines have been developed against Taenia ovis infection in sheep, Taenia saginata infection in cattle, Taenia solium infection in pigs, Echinococcus granulosus and Echinococcus multilocularis infections in a variety of intermediate host species. These vaccines have been based on the identification and expression in Escherichia coli of antigens derived from the oncosphere life cycle stage, contained within the parasites' eggs. Investigation of the molecular aspects of these proteins and the genes encoding them have revealed a number of common features, including the presence of a predicted secretory signal sequence, and one or two copies of a fibronectin type III domain, each encoded by separate exons within the associated gene. Evidence has been obtained to confirm glycosylation of some of these antigens. Ongoing investigations will shed light on the biological roles played by the proteins within the parasites and the mechanism by which they make the parasites vulnerable to vaccine-induced immune responses.

Turing learning: : A metric-free approach to inferring behavior and its application to swarms

We propose Turing Learning, a novel system identification method for inferring the behavior of natural or artificial systems. Turing Learning simultaneously optimizes two populations of computer programs, one representing models of the behavior of the system under investigation, and the other representing classifiers. By observing the behavior of the system as well as the behaviors produced by the models, two sets of data samples are obtained. The classifiers are rewarded for discriminating between these two sets, that is, for correctly categorizing data samples as either genuine or counterfeit. Conversely, the models are rewarded for 'tricking' the classifiers into categorizing their data samples as genuine. Unlike other methods for system identification, Turing Learning does not require predefined metrics to quantify the difference between the system and its models. We present two case studies with swarms of simulated robots and prove that the underlying behaviors cannot be inferred by a metric-based system identification method. By contrast, Turing Learning infers the behaviors with high accuracy. It also produces a useful by-product - the classifiers - that can be used to detect abnormal behavior in the swarm. Moreover, we show that Turing Learning also successfully infers the behavior of physical robot swarms. The results show that collective behaviors can be directly inferred from motion trajectories of individuals in the swarm, which may have significant implications for the study of animal collectives. Furthermore, Turing Learning could prove useful whenever a behavior is not easily characterizable using metrics, making it suitable for a wide range of applications.Comment: camera-ready versio