Long-Term Biometeorological Monitoring at Two Forest Sites in Iceland and Newfoundland: Initial Results

ABSTRACTThe interface between Hg1-xCdxTe(0 ≦ x ≦ 1) and Hg1-yCdyTe(0 ≦ y ≦ 1) epitaxial layers of different composition (x ≠ y) is unstable with regard to the intermixing of the Hg and Cd cations within the Group II sublattice. This phenomenon may give rise to long-term stability problems in HgTe-(Hg,Cd)Te superlattices and composition grading between (Hg,Cd)Te absorber layers and CdTe buffer or passivation layers in epitaxial infra red detectors. In this paper, a novel approach to the inhibition of interdiffusion in these systems is discussed. This involves the growth of an intervening ZnTe barrier layer at the heterointerface between two (Hg,Cd)Te layers. Initial results are presented which indicate the effectiveness of this technique in reducing interdiffusion in an experimental heterostructure grown by MOVPE. Some possible applications in a variety of HgTe-based long wavelength devices are discussed.

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Initial results and long-term clinical follow-up of an amorphous hydrogenated silicon-carbide-coated stent in daily practice

International Journal of Cardiovascular Interventions ◽

10.1080/acc.1.2.81.85 ◽

1998 ◽

Vol 1 (2) ◽

pp. 81-85

Author(s):

Clara EE Hanekamp ◽

Hans JRM Bonnier ◽

Rolf H Michels ◽

Kathinka H Peels ◽

Eric PCM Heijmen ◽

...

Keyword(s):

Silicon Carbide ◽

Daily Practice ◽

Hydrogenated Silicon ◽

Amorphous Hydrogenated Silicon ◽

Initial Results

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INITIAL RESULTS AND LONG-TERM FOLLOW-UP OF PERCUTANEOUS MITRAL VALVULOPLASTY IN PATIENTS WITH PULMONARY HYPERTENSION

Journal of the American College of Cardiology ◽

10.1016/s0735-1097(17)34648-x ◽

2017 ◽

Vol 69 (11) ◽

pp. 1259

Author(s):

Rafael A. Meneguz-Moreno ◽

Jose de Ribamar Costa ◽

Auristela Ramos ◽

Nisia Gomes ◽

Zilda Meneghelo ◽

...

Keyword(s):

Pulmonary Hypertension ◽

Mitral Valvuloplasty ◽

Long Term Follow Up ◽

Initial Results

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Modelling tropical forest responses to drought and El Niño with a stomatal optimization model based on xylem hydraulics

Philosophical Transactions of the Royal Society B Biological Sciences ◽

10.1098/rstb.2017.0315 ◽

2018 ◽

Vol 373 (1760) ◽

pp. 20170315 ◽

Cited By ~ 34

Author(s):

Cleiton B. Eller ◽

Lucy Rowland ◽

Rafael S. Oliveira ◽

Paulo R. L. Bittencourt ◽

Fernanda V. Barros ◽

...

Keyword(s):

Tropical Forest ◽

El Niño ◽

Optimization Model ◽

El Nino ◽

Soil Drought ◽

Forest Sites ◽

Dynamic Global Vegetation Models ◽

Vegetation Models ◽

Global Vegetation

The current generation of dynamic global vegetation models (DGVMs) lacks a mechanistic representation of vegetation responses to soil drought, impairing their ability to accurately predict Earth system responses to future climate scenarios and climatic anomalies, such as El Niño events. We propose a simple numerical approach to model plant responses to drought coupling stomatal optimality theory and plant hydraulics that can be used in dynamic global vegetation models (DGVMs). The model is validated against stand-scale forest transpiration ( E ) observations from a long-term soil drought experiment and used to predict the response of three Amazonian forest sites to climatic anomalies during the twentieth century. We show that our stomatal optimization model produces realistic stomatal responses to environmental conditions and can accurately simulate how tropical forest E responds to seasonal, and even long-term soil drought. Our model predicts a stronger cumulative effect of climatic anomalies in Amazon forest sites exposed to soil drought during El Niño years than can be captured by alternative empirical drought representation schemes. The contrasting responses between our model and empirical drought factors highlight the utility of hydraulically-based stomatal optimization models to represent vegetation responses to drought and climatic anomalies in DGVMs. This article is part of a discussion meeting issue ‘The impact of the 2015/2016 El Niño on the terrestrial tropical carbon cycle: patterns, mechanisms and implications’.

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Atmospheric Heavy Metal Input to Forest Soils in Rural Areas of Denmark

The Scientific World JOURNAL ◽

10.1100/tsw.2007.41 ◽

2007 ◽

Vol 7 ◽

pp. 192-197 ◽

Cited By ~ 2

Author(s):

M. F. Hovmand ◽

Kaare Kemp

Keyword(s):

Heavy Metals ◽

Heavy Metal ◽

Rural Areas ◽

Forest Floor ◽

Ambient Atmosphere ◽

Chronological Order ◽

Forest Sites ◽

Yearly Average ◽

Atmospheric Inputs

Atmospheric bulk deposition of heavy metals (HM) was measured from 1972/73 to the present time at five to ten forest sites in rural areas of Denmark. From 1979, HM in aerosols were measured at one to four forest sites. On the basis of these long-term continuous measurements, the atmospheric inputs to the forest floor have been calculated. Yearly HM emission estimates to the European atmosphere seems to correlate well with yearly average values of HM deposition, as well as with HM concentrations in the ambient atmosphere. HM emissions have been estimated since the 1950s. Using the correlation between emission and deposition, HM deposition values maybe extrapolated in reverse chronological order. The accumulated atmospheric HM deposition has been estimated in this way over a period of 50 years.

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Evaluation of long-term BeiDou/GPS observation quality based on G-Nut/Anubis and initial results

Acta Geodynamica et Geomaterialia ◽

10.13168/agg.2018.0006 ◽

2018 ◽

pp. 77-85

Author(s):

Lewen Zhao

Keyword(s):

Gps Observation ◽

Initial Results

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In Situ Performance Assessment and Evaluation of Hydrophobic and Ultraviolet Protective Treatments for Historic Log Structures

The UW National Parks Service Research Station Annual Reports ◽

10.13001/uwnpsrc.2015.4105 ◽

2015 ◽

Vol 38 ◽

pp. 100-111

Author(s):

Courtney Magill ◽

Frank Matero

Keyword(s):

Field Research ◽

Accelerated Weathering ◽

Assessment And Evaluation ◽

Appropriate Treatment ◽

Wood Coatings ◽

Subsequent Phase ◽

Initial Results ◽

Ongoing Project

Beginning in the summer of 2015, research was conducted on protective wood coatings and accelerated weathering testing methods for architectural log and timber. A rack for supplementary natural weathering testing of hydrophobic and ultraviolet protective surface treatments for logs was also erected as a subsequent phase at Grand Teton National Park. This laboratory and field research is part of an ongoing project to develop an appropriate treatment for historic log structures in the region that will preserve their original fabric while maintaining the intended historic appearance of the buildings, i.e., unpainted. The weathering rack will be in place for upwards of five years to verify the lab-based results from Phase I and to determine the long-term durability of the chosen treatments on already aged materials in situ. This report addresses the methods and materials for preparation of the weathering rack and samples as well as the methods being used to monitor their progress and initial results. Readings will be taken yearly to monitor the effects of weathering on each treatment.

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Mosaics of canopy openness induced by tropical cyclones in lowland rain forests with contrasting management histories in northeastern Australia

Journal of Tropical Ecology ◽

10.1017/s0266467400001784 ◽

2000 ◽

Vol 16 (6) ◽

pp. 883-894 ◽

Cited By ~ 43

Author(s):

SIMON J. GROVE ◽

STEPHEN M. TURTON ◽

DANNY T. SIEGENTHALER

Keyword(s):

Forest Management ◽

Forest Canopy ◽

Canopy Openness ◽

Old Growth ◽

Lowland Rain Forest ◽

Forest Sites ◽

Local Topography ◽

Marked Points ◽

Impacted Site

Tropical Cyclone ‘Rona’ crossed the coast of the Daintree lowlands of northeastern Australia in 1999. This study reports on its impact on forest canopy openness at six lowland rain forest sites with contrasting management histories (old-growth, selectively logged and regrowth). Percentage canopy openness was calculated from individual hemispherical photographs taken from marked points below the forest canopy at nine plots per site 3–4 mo before the cyclone, and at the same points a month afterwards. Before the cyclone, when nine sites were visited, canopy openness in old-growth and logged sites was similar, but significantly higher in regrowth forest. After the cyclone, all six revisited sites showed an increase in canopy openness, but the increase was very patchy amongst plots and sites and varied from insignificant to severe. The most severely impacted site was an old-growth one, the least impacted a logged one. Although proneness to impact was apparently related to forest management history (old-growth being the most impacted), underlying local topography may have had an equally strong influence in this case. It was concluded that the likelihood of severe impact may be determined at the landscape-scale by the interaction of anthropogenic with meteorological, physiographic and biotic factors. In the long term, such interactions may caution against pursuing forest management in cyclone-prone areas.

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Analysing the relationship of CO2 and O2 concentrations and flux patterns in forest soils

10.5194/egusphere-egu21-7442 ◽

2021 ◽

Author(s):

Valentin Gartiser ◽

Verena Lang ◽

Martin Maier

Keyword(s):

Diffusion Coefficient ◽

Organic Material ◽

West Germany ◽

Atmospheric Environment ◽

Concentration Data ◽

Forest Sites ◽

Production And Consumption ◽

Different Depths ◽

Relationship Of

Soils act as bioreactors for the production and consumption of different gases. CO2 is usually produced in soils due to the oxidation of organic material. Under aerobic conditions, this production is coupled to a consumption of O2 resulting in concentration profiles that increase with depth for CO2 and decrease for O2. Depending on the organic material present, the exchange of O2 and CO2 is approximately equimolar in well aerated soils. This can be deduced from vertical gradients of both gases which should reflect the ratio of their diffusion coefficient (Massmann 1998). The ratio between the CO2 and O2 flux is often called the respiratory coefficient. However, certain soil types or conditions may invoke anaerobe processes that may lead to a decoupling of CO2 production and O2 consumption. Such a decoupling can also result from oxidation of minerals or dissolution and relocation of carbonates.Here we present long-term data of soil CO2 and O2 concentrations from forest sites in South West Germany. Gas samples were collected passively starting 1998 until now using permanently installed gas wells at different depths. The samples were then analysed using gas chromatography for CO2 and O2 (and additionally N2, Ar, N2O, CH4, and C2H4).CO2 and O2 fluxes were calculated using the gradient approach (Maier et al 2020). At sites with well aerated soils, the observed CO2 and O2 fluxes followed a clear linear relationship, with high effluxes of CO2 corresponding to high influxes of O2. The exchange was furthermore approximately equimolar with the calculated fluxes following a -1:1 trend.We will compare these data from well aerated soils to concentration data of CO2 and O2 from less well-aerated soils with temporally suboxic conditions to further analyse the respiratory coefficient under oxygen limited conditions. Furthermore, diffusion-coefficient-normalised gradients are calculated to obtain information about the stoichiometry of the production and consumption patterns involved.&#160;Literature:Maier M, Gartiser V, Schengel A, Lang V. Long Term Soil Gas Monitoring as Tool to Understand Soil Processes. Applied Sciences. 2020; 10(23):8653.Massman, W J. A review of the molecular diffusivities of H2O, CO2, CH4, CO, O3, SO2, NH3, N2O, NO, and NO2 in air, O2 and N2 near STP. Atmospheric Environment 1998; 32(6), 1111&#8211;1127&#160;

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