169,898 research outputs found
Estimating changes in Scottish soil carbon stocks using ECOSSE. II. Application
Get PDFIn order to predict the response of carbon (C)-rich soils to external change, models are
needed that accurately reflect the conditions of these soils. Here we present an example application
of the new Estimation of Carbon in Organic Soils – Sequestration and Emissions (ECOSSE) model to
estimate net change in soil C in response to changes in land use in Scotland. The ECOSSE estimate
of annual change in soil C stocks for Scotland between 2000 and 2009 is –810 ± 89 kt yr–1, equivalent
to 0.037 ± 0.004% yr–1. Increasing the area of land-use change from arable to grass has the greatest
potential to sequester soil C, and reducing the area of change from grass to arable has the greatest
potential to reduce losses of soil C. Across Scotland, simulated changes in soil C from C-rich soils
(C content >6%) between 1950 and 2009 is –63 Mt, compared with –35 Mt from non-C-rich mineral
soils; losses from C-rich soils between 2000 and 2009 make up 64% of the total soil C losses. One
mitigation option that could be used in upland soils to achieve zero net loss of C from Scottish soils
is to stop conversion of semi-natural land to grassland and increase conversion of grassland to seminatural
land by 125% relative to the present rate. Mitigation options involving forestry are not
included here because the data available to calculate losses of soil C do not account for losses of soil C on drainage of semi-natural lan
Études sur les Nègres de la Nouvelle Ecosse.
No full textC. P. Études sur les Nègres de la Nouvelle Ecosse. In: Journal de la Société des Américanistes. Tome 16, 1924. p. 412
Evaluation of the ECOSSE model for simulating soilcarbon under short rotation forestry energy crops in Britain
No full textUnderstanding and predicting the effects of land-use change to short rotation forestry (SRF) on soil carbon (C) is an important requirement for fully assessing the C mitigation potential of SRF as a bioenergy crop. There is little current knowledge of SRF in the UK and in particular a lack of consistent measured data sets on the direct impacts of land use change on soil C stocks. The ECOSSE model was developed to simulate soil C dynamics and greenhouse gas (GHG) emissions in mineral and organic soils. The ECOSSE model has already been applied spatially to simulate land-use change impacts on soil C and GHG emissions. However, it has not been extensively evaluated under SRF. Eleven sites comprising 29 transitions in Britain, representing land-use change from nonwoodland land uses to SRF, were selected to evaluate the performance of ECOSSE in predicting soil C and soil C change in SRF plantations. The modelled C under SRF showed a strong correlation with the soil C measurements at both 0–30 cm (R = 0.93) and 0–100 cm soil depth (R = 0.82). As for the SRF plots, the soil C at the reference sites have been accurately simulated by the model. The extremely high correlation for the reference fields (R ≥ 0.99) shows a good performance of the model spin-up. The statistical analysis of the model performance to simulate soil C and soil C changes after land-use change to SRF highlighted the absence of significant error between modelled and measured values as well as the absence of significant bias in the model. Overall, this evaluation reinforces previous studies on the ability of ECOSSE to simulate soil C and emphasize its accuracy to simulate soil C under SRF plantations
Estimating changes in Scottish soil carbon stocks using ECOSSE. I. Model description and uncertainties
Get PDFTo predict the response of C-rich soils to external change, models are needed that accurately
reflect the conditions of these soils. Estimation of Carbon in Organic Soils—Sequestration and
Emissions (ECOSSE) is a model that allows simulations of soil C and N turnover in both mineral and
organic soils using only the limited meteorological, land-use and soil data that is available at the
national scale. Because it is able to function at field as well as national scales if appropriate input data
are used, field-scale evaluations can be used to determine uncertainty in national simulations. Here
we present an evaluation of the uncertainty expected in national-scale simulations of Scotland, using
data from the National Soil Inventory of Scotland. This data set provides measurements of C change
for the range of soils, climates and land-use types found across Scotland. The simulated values show
a high degree of association with the measurements in both total C and change in C content of the
soil. Over all sites where land-use change occurred, the average deviation between the simulated
and measured values of percentage change in soil C was less than the experimental error (11% simulation
error, 53% measurement error). This suggests that the uncertainty in the national-scale simulations
will be ~11%. Only a small bias in the simulations was observed compared to the measured
values, suggesting that a small underestimate of the change in soil C should be expected at the
national scale (–4%
Mary Stewart, Queen of France and Scotland (Marie Stewart Reyne de France et d Ecosse)
No full textMedium: engravingprintsBot. c.: Th. D. Leu F. et ex."Mary Stewart, Queen of France and Scotland (Marie Stewart Reyne de France et d Ecosse)" [0000.1165.104.000], Leu, Thomas DeArtist and Role: Leu, Thomas De,Extent: plat
Evaluation of the ECOSSE model for simulating soil carbon under short rotation forestry energy crops in Britain
Get PDFUnderstanding and predicting the effects of land-use change to short rotation forestry (SRF) on soil C is an important requirement for fully assessing the C mitigation potential of SRF as a bioenergy crop. There is little current knowledge of SRF in the UK and in particular a lack of consistent measured datasets on the direct impacts of land use change on soil C stocks.
The ECOSSE model was developed to simulate soil C dynamics and greenhouse gas (GHG) emissions in mineral and organic soils. The ECOSSE model has already been applied spatially to simulate land-use change impacts on soil C and GHG emissions. However, it has not been extensively evaluated under SRF.
Eleven sites comprising 29 transitions in Britain, representing land-use change from non-woodland land uses to SRF, were selected to evaluate the performance of ECOSSE in predicting soil C and soil C change in SRF plantations.
The modelled C under SRF showed a strong correlation with the soil C measurements at both 0-30 cm (R = 0.93) and 0-100 cm soil depth (R = 0.82). As for the SRF plots, the soil C at the reference sites have been accurately simulated by the model. The extremely high correlation for the reference fields (R ≥ 0.99) shows a good performance of the model spin-up. The statistical analysis of the model performance to simulate soil C and soil C changes after land-use change to SRF highlighted the absence of significant error between modelled and measured values as well as the absence of significant bias in the model.
Overall, this evaluation reinforces previous studies on the ability of ECOSSE to simulate soil C and emphasize its accuracy to simulate soil C under SRF plantations
Going Beyond Counting First Authors in Author Co-citation Analysis
Get PDFThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Evaluation of the ecosse model for simulating methane and carbon dioxide fluxes in soils from a forest and an anthropogenic peatland in Chiloe island
Get PDFMemoria para optar al Título Profesional de Ingeniera en Recursos Naturales RenovablesEl suelo es considerado un regulador crítico del balance global de carbono (C) a través de sus mecanismos de almacenaje y emisión. Este elemento interactúa con la atmósfera principalmente en forma de gases de efecto invernadero (GEI) como dióxido de carbono (CO2) y metano (CH4). Los bosques y las turberas destacan como ecosistemas capaces de almacenar grandes cantidades de C, siendo los suelos una fuente o sumidero de C, según su capacidad de emitir o secuestrar dichos gases. Para simular y predecir la dinámica de los procesos que ocurren en él se utilizan modelos mecanísticos, dentro de los que destaca el modelo ECOSSE. Éste corresponde a un modelo de suelos basado en procesos, capaz de simular la dinámica del C y nitrógeno y las emisiones de GEI en suelos orgánicos o minerales. En este estudio se evaluó la aplicabilidad del modelo ECOSSE para simular los flujos de CO2 y CH4 en suelos de un bosque y una turbera antropogénica en la Estación Biológica Senda Darwin (EBSD), ubicada en la isla de Chiloé
Mitomycin C in highly myopic eyes - Author reply
No full textOphthalmology. 2005 Feb;112(2):208-18; discussion 219.
Mitomycin C modulation of corneal wound healing after photorefractive keratectomy in highly myopic eyes.
Gambato C, Ghirlando A, Moretto E, Busato F, Midena E.
SourceRefractive Surgery Service and Antimetabolite Therapy Research Unit, Department of Ophthalmology, University of Padova, Padova, Italy.
Abstract
PURPOSE: To evaluate the role of topical mitomycin C in corneal wound healing (CWH) after photorefractive keratectomy (PRK) in highly myopic eyes.
DESIGN: Prospective, double-masked, randomized clinical trial.
PARTICIPANTS: Seventy-two eyes of 36 patients affected by high (>7 diopters) myopia.
METHODS: In each patient, one eye was randomly assigned to PRK with intraoperative topical 0.02% mitomycin C application, and the fellow eye was treated with a placebo. Postoperatively, mitomycin C-treated eyes received artificial tears (3 times daily, tapered in 3 months), whereas the fellow eye was treated with fluorometholone sodium 2% and artificial tears (3 times daily, tapered in 3 months).
MAIN OUTCOME MEASURES: Uncorrected visual acuity (UCVA) and best-corrected visual acuity (BCVA), contrast sensitivity, manifest refraction, and biomicroscopy. Contrast sensitivity was determined using the Pelli-Robson chart. Corneal confocal microscopy documented CWH.
RESULTS: Mean follow-up was 18 months (range, 12-36). No side effects or toxic effects were documented. At 12-month follow-up examination, UCVAs (logarithm of the minimum angle of resolution) were 0.4+/-0.48 and 0.5+/-0.53 (P = .03) in mitomycin C-treated eyes and corticosteroid-treated eyes, respectively. At 1 year, corneal haze developed in 20% of corticosteroid-treated eyes, versus 0% of mitomycin C-treated eyes. At 12, 24, and 36 months, corneal confocal microscopy showed activated keratocytes and extracellular matrix significantly more evident in untreated eyes (Ps = 0.004, 0.024, and 0.046, respectively).
CONCLUSION: Topical intraoperative application of 0.02% mitomycin C can reduce haze formation in highly myopic eyes undergoing PRK.
Comment in
Ophthalmology. 2006 Feb;113(2):357; author reply 357-8
Vigueur de l'hôte et biologie hivernale du dendroctone de l'épinette (Dendroctonus rufipennis) de la Nouvelle-Ecosse, Canada
No full textNous avons évalué l'effet de la vigueur de l'hôte sur la biologie hivernale des dendroctones de l'épinette adultes de la Nouvelle-Ecosse. Ceux-ci n'ont pas produit plus de cryoprotectant, n'ont pas résisté à des températures plus froides et n'ont pas présenté un plus haut taux de survie sur les arbres plus vigoureux. Tout hôte confondu, ils ont présenté des points de surfusion et des taux de mortalité relativement bas (15%) démontrant ainsi une grande résistance au froid. Les points de surfusion sont descendus jusqu'à -44°C en janvier alors que la température la plus froide enregistrée sur le site était de -23°C. Ces résultats nous permettent de mieux comprendre la dynamique des infestations de dendroctones de l'épinette et de fournir de l'information sur la biologie hivernale de cet insecte qui est peu connue pour les conditions climatiques de la Nouvelle-Ecosse
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