210 research outputs found
The Hidden Half: Blanket Bog Microbial Communities across a Spectrum of Site and Management Conditions and Impacts on Peatland Carbon Cycling
Monitoring blanket bog condition and functions is critical in ensuring the ecosystem services they provide, especially as their environment becomes increasingly pressured. Microbial DNA-based monitoring tools allow the assessment of soil communities, but our knowledge of the microbial processes underpinning ecosystem service provision is limited. Specifically, (a) how microbial communities vary with management and climate, (b) how the microbial community is related to environmental variables, and (c) whether microbial community measurements can be used to predict water quality and carbon fluxes, including methane.
Here, microbial community taxonomy and fungal community function was measured on UK blanket bog with different management, habitat, or restoration status using sequencing techniques, alongside a novel carbon partitioning mesocosm experiment. Water quality variables were measured alongside this experimental setup, along with a suite of environmental, chemical, and soil edaphic variables.
Fungal, bacterial, and archaeal microbial communities changed with management and location. Microbial communities were highly variable but showed some categorisation based on climatic conditions. Communities subject to managed grouse moor burning were frequently different from every other habitat category.
Concentrations of zinc, magnesium, and calcium were strongly associated with microbial community structure, alongside soil temperature, rainfall, and the abundance of Calluna vulgaris. Blanket bogs with a legacy of pollution contained specifically adapted microbial taxa.
Grouse moor burning was linked to changes in fungal trophic groups, with potential consequences for water quality. Changes to the fungal and bacterial communities, alongside the abundance of sedges, were linked to changes in methane flux, and fungal community change was linked to soil respiration.
The findings here indicate that ecosystem services can be linked to management and habitat status via microbial processes, but that our knowledge remains incomplete. This thesis provides the basis for further in-depth experiments and recommends focusing on a functional, rather than a taxonomy, based approach
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Secondary Natural Gas Recovery: Targeted Technology Applications for Infield Reserve Growth: Case Studies Evaluating the Benefits of Secondary Gas Recovery, Onshore Gulf Coast, South Texas
Economic recovery of natural gas in reservoirs with near-tight to conventional porosity and permeability can be improved through geologically based infill-development strategies. Old gas fields may contain new infield reservoirs, incompletely drained reservoir compartments, untapped reservoir compartments, and bypassed reservoirs. These secondary resources may be identified by a combination of log evaluation and production and pressure analyses, and they are controlled by structural and stratigraphic heterogeneity. Many gas fields in the Gulf Coast may contain opportunities for identifying additional gas resources at modest costs. Remaining natural gas in these fields can be contacted either by recompleting existing wells that have bypassed reservoir compartments or by drilling strategically targeted infield wells. Exploration for new, untapped, or incompletely drained reservoir compartments or bypassed gas zones in old fields can be improved by using state-of-the-art formation evaluation tools and engineering, production, petrophysical, and geological analyses. The economics of developing and producing the secondary gas recovery (SGR) resource is evaluated for two producing properties in existing fields. The case I study area (North Mcfaddin field) had total operational and development costs (excluding royalties) of 0.83 per mcf. Future application of SGR concepts and technology to strategically targeted well locations and recompletions could further lower development costs.Bureau of Economic Geolog
Annealing-enhanced birefringence and aggregation in MEH-PPV : a spectroscopic ellipsometry study
Funding: UK EPSRC (GR/S62628/01) and Royal Society Wolfson Research Merit Award (I.D.W.S.).We have used absorption, photoluminescence (PL) and variable angle spectroscopic ellipsometry (VASE) measurements to investigate the structural changes that take place upon high temperature annealing in spin-coated films of the prototypical conjugated polymer (CP) poly[2-(2’-ethylhexyloxy)-5-methoxy-1,4-phenylenevinylene] (MEH-PPV). Absorption and VASE measurements reveal that the birefringence of the films increases by approximately a factor of two upon heating, which indicates significant increase in the alignment of the conjugated polymer (CP) strands within the film plane. Absorption and PL spectra indicate the formation in annealed films of interchain species having lower energy transitions. But these measurements alone do not reveal the type of interchain species formed, such as excimers or aggregates. VASE measurements were used to investigate this feature and clearly reveal a new, low energy, feature with a shoulder at 650 nm in the dispersion relations of the extraordinary (out-of-plane) extinction and absorption coefficients of annealed films, which we assign to aggregate absorption. Thus, our work shows that VASE is a sensitive enough technique to measure aggregate absorption in CP films. In the case of the ordinary (in-plane) extinction and absorption coefficients, there is increased amplitude of the lower energy peak upon heating, owing to increased uniaxial anisotropy, along with a broadening and a longer red-tail, but the well-resolved red-shifted absorption band seen for the extraordinary absorption coefficient, is not observed. Therefore, we conclude that while in-plane and out-of-plane aggregation occurs in annealed spin-coated films of MEH-PPV, aggregate absorption is only clearly observed when the aggregate electronic transition dipole is oriented preferentially in a direction perpendicular to the film plane. This conclusion is consistent with the usual observation that aggregate absorption in MEH-PPV films is not easily observed using absorption spectra alone, which are typically measured at normal incidence.PostprintPeer reviewe
Self-Generated Magnetic Fields in Galactic Cooling Flows
Interstellar magnetic fields in elliptical galaxies are assumed to have their
origin in stellar fields that accompany normal mass loss from an evolving
population of old stars. The seed fields are amplified by interstellar
turbulence driven by stellar mass loss and supernova events. These disordered
fields are further amplified by time-dependent compression in the inward moving
galactic cooling flow and are expected to dominate near the galactic core.
Under favorable circumstances, fields similar in strength to those observed G can be generated solely from these natural
galactic processes. In general the interstellar field throughout elliptical
galaxies is determined by the outermost regions in the interstellar gas where
the turbulent dynamo process can occur. Because of the long hydrodynamic flow
times in galactic cooling flows, currently observed magnetic fields may result
from periods of intense turbulent field amplification that occurred in the
outer galaxy in the distant past. Particularly strong fields in ellipticals may
result from ancient galactic mergers or shear turbulence introduced at the
boundary between the interstellar gas and ambient cluster gas.Comment: 21 pages in AASTEX LaTeX with 2 figures; accepted by Astrophysical
Journa
Response to comment on “Peatland carbon stocks and burn history: Blanket bog peat core evidence highlights charcoal impacts on peat physical properties and long‐term carbon storage” by Evans et al.
We would like to thank the authors Evans et al. for submitting a comment on our recent publication “Peatland carbon stocks and burn history: Blanket bog peat core evidence highlights charcoal impacts on peat physical properties and long‐term carbon storage”, we especially value their direct and open approach
Evaluation of the Algorithms and Parameterizations for Ground Thawing and Freezing Simulation in Permafrost Regions
Ground thawing and freezing depths (GTFDs) strongly influence the hydrology and energy balances of permafrost regions. Current methods to simulate GTFD differ in algorithm type, soil parameterization, representation of latent heat, and unfrozen water content. In this study, five algorithms (one semiempirical, two analytical, and two numerical), three soil thermal conductivity parameterizations, and three unfrozen water parameterizations were evaluated against detailed field measurements at four field sites in Canada’s discontinuous permafrost region. Key findings include: (1) de Vries’ parameterization is recommended to determine the thermal conductivity in permafrost soils; (2) the three unfrozen water parameterization methods exhibited little difference in terms of GTFD simulations, yet the segmented linear function is the simplest to be implemented; (3) the semiempirical algorithm reasonably simulates thawing at permafrost sites and freezing at seasonal frost sites with site-specific calibration. However, large interannual and intersite variations in calibration coefficients limit its applicability for dynamic analysis; (4) when driven by surface forcing, analytical algorithms performed marginally better than the semiempirical algorithm. The inclusion of bottom forcing improved analytical algorithm performance, yet their results were still poor compared with those achieved by numerical algorithms; (5) when supplied with the optimal inputs, soil parameterizations, and model configurations, the numerical algorithm with latent heat treated as an apparent heat capacity achieved the best GTFD simulations among all algorithms at all sites. Replacing the observed bottom temperature with a zero heat flux boundary condition did not significantly reduce simulation accuracy, while assuming a saturated profile caused large errors at several sites
Neutron reflection study on soluble and insoluble poly[2-(2 '-ethylhexyloxy)-5-methoxy-1,4-phenylenevinylene) films
Neutron reflection (NR) has been utilized to study the physical structure of the light-emitting polymer poly[2-(2'-ethylhexyloxy)-5-methoxy-1,4-phenylenevinylene) (MEHPPV). Films of soluble MEHPPV (S-MEHPPV) and insoluble MEHPPV (I-MEHPPV) prepared via a chloro precursor polymer were investigated. For S-MEHPPV spin-coated films were found to contain two layers, one of low-density and thickness of approximate to1360 Angstrom with the second layer being thinner, approximate to240 Angstrom, but denser. The thicker layer only covered about 30% of the substrate surface. In contrast, I-MEHPPV formed uniform films across the substrate. We found that during the thermal conversion of the chloro precursor polymer the film thickness was maintained and it was only on cooling that the films contracted. Importantly, the thermal expansion and contraction of I-MEHPPV was reversible. NR showed that thermal annealing of I-MEHPPV had little affect on the films physical structure while for S-MEHPPV only the thinner layer was changed and became more dense. Photoluminescence spectra of S-MEHPPV before and after annealing showed that the densification observed in the neutron reflection measurements was mirrored in the emission properties of the polymer film. (C) 2002 American Institute of Physics
Association between vision impairment and mortality: protocol for a systematic review and meta-analysis.
Funder: Christian Blind MissionFunder: Queen Elizabeth Diamond Jubilee TrustFunder: Seva FoundationFunder: NIHR Moorfields Biomedical Research CentreFunder: British Council for the Prevention of BlindnessFunder: Sightsavers International; FundRef: http://dx.doi.org/10.13039/501100004324Funder: Fred Hollows Foundation; FundRef: http://dx.doi.org/10.13039/100014445INTRODUCTION: Due to growth and ageing of the world's population, the number of individuals worldwide with vision impairment (VI) and blindness is projected to increase rapidly over the coming decades. VI and blindness are an important cause of years lived with disability. However, the association of VI and blindness with mortality, including the risk of bias in published studies and certainty of the evidence, has not been adequately studied in an up-to-date systematic review and meta-analysis. METHODS AND ANALYSIS: The planned systematic review and meta-analysis will adhere to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. Databases, including MEDLINE Ovid, Embase Ovid and Global Health, will be searched for relevant studies. Two reviewers will then screen studies and review full texts to identify studies for inclusion. Data extraction will be performed, and for included studies, the risk of bias and certainty of the evidence will be assessed using the Grades of Recommendation, Assessment, Development and Evaluation approach. The prognostic factor in this study is visual function, which must have been measured using a standard objective ophthalmic clinical or research instrument. We will use standard criteria from WHO to categorise VI and blindness. All-cause mortality may be assessed by any method one or more years after baseline assessment of vision. Results from included studies will be meta-analysed according to relevant sections of the Meta-analysis Of Observational Studies in Epidemiology checklist. ETHICS AND DISSEMINATION: This review will only include published data; therefore, ethics approval will not be sought. The findings of this review and meta-analysis will be published in an open-access, peer-reviewed journal and will be included in the ongoing Lancet Global Health Commission on Global Eye Health
A multi-targeted approach to suppress tumor-promoting inflammation
Cancers harbor significant genetic heterogeneity and patterns of relapse following many therapies are due to evolved resistance to treatment. While efforts have been made to combine targeted therapies, significant levels of toxicity have stymied efforts to effectively treat cancer with multi-drug combinations using currently approved therapeutics. We discuss the relationship between tumor-promoting inflammation and cancer as part of a larger effort to develop a broad-spectrum therapeutic approach aimed at a wide range of targets to address this heterogeneity. Specifically, macrophage migration inhibitory factor, cyclooxygenase-2, transcription factor nuclear factor-κB, tumor necrosis factor alpha, inducible nitric oxide synthase, protein kinase B, and CXC chemokines are reviewed as important antiinflammatory targets while curcumin, resveratrol, epigallocatechin gallate, genistein, lycopene, and anthocyanins are reviewed as low-cost, low toxicity means by which these targets might all be reached simultaneously. Future translational work will need to assess the resulting synergies of rationally designed antiinflammatory mixtures (employing low-toxicity constituents), and then combine this with similar approaches targeting the most important pathways across the range of cancer hallmark phenotypes
Three Warm Jupiters around Solar-analog Stars Detected with TESS*
We report the discovery and characterization of three giant exoplanets orbiting solar-analog stars, detected by the TESS space mission and confirmed through ground-based photometry and radial velocity measurements taken at La Silla observatory with FEROS. TOI-2373 b is a warm Jupiter orbiting its host star every ∼13.3 days, and is one of the most massive known exoplanet with a precisely determined mass and radius around a star similar to the Sun, with an estimated mass of m _p = and a radius of r _p = . With a mean density of , TOI-2373 b is among the densest planets discovered so far. TOI-2416 b orbits its host star on a moderately eccentric orbit with a period of ∼8.3 days and an eccentricity of e = . TOI-2416 b is more massive than Jupiter with m _p = , however is significantly smaller with a radius of r _p = , leading to a high mean density of . TOI-2524 b is a warm Jupiter near the hot Jupiter transition region, orbiting its star every ∼7.2 days on a circular orbit. It is less massive than Jupiter with a mass of m _p = , and is consistent with an inflated radius of r _p = , leading to a low mean density of . The newly discovered exoplanets TOI-2373 b, TOI-2416 b, and TOI-2524 b have estimated equilibrium temperatures of K, K, and K, respectively, placing them in the sparsely populated transition zone between hot and warm Jupiters
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