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Sample records for forest floor horizons

  1. Linking chemical elements in forest floor humus (Oh-horizon) in the Czech Republic to contamination sources

    International Nuclear Information System (INIS)

    Sucharova, Julie; Suchara, Ivan; Hola, Marie; Reimann, Clemens; Boyd, Rognvald; Filzmoser, Peter; Englmaier, Peter

    2011-01-01

    While terrestrial moss and other plants are frequently used for environmental mapping and monitoring projects, data on the regional geochemistry of humus are scarce. Humus, however, has a much larger life span than any plant material. It can be seen as the 'environmental memory' of an area for at least the last 60-100 years. Here concentrations of 39 elements determined by ICP-MS and ICP AES, pH and ash content are presented for 259 samples of forest floor humus collected at an average sample density of 1 site/300 km 2 in the Czech Republic. The scale of anomalies linked to known contamination sources (e.g., lignite mining and burning, metallurgical industry, coal fired power plants, metal smelters) is documented and discussed versus natural processes influencing humus quality. Most maps indicate a local impact from individual contamination sources: often more detailed sampling than used here would be needed to differentiate between likely sources. - Highlights: → Concentrations of 39 elements in forest floor humus are provided. → The capabilities of humus sampling for bio-monitoring purposes are demonstrated. → Geochemical anomalies are linked to known contamination sources. → The study shows the importance of scale for geochemical mapping projects. → Humus provides a picture of the long term contamination history of a country. - Forest floor humus, the atmosphere-biosphere-pedosphere interface, archives an environmental contamination signal over long time periods.

  2. A model of forest floor carbon mass for United States forest types

    Science.gov (United States)

    James E. Smith; Linda S. Heath

    2002-01-01

    Includes a large set of published values of forest floor mass and develop large-scale estimates of carbon mass according to region and forest type. Estimates of average forest floor carbon mass per hectare of forest applied to a 1997 summary forest inventory, sum to 4.5 Gt carbon stored in forests of the 48 contiguous United States.

  3. Linking chemical elements in forest floor humus (O{sub h}-horizon) in the Czech Republic to contamination sources

    Energy Technology Data Exchange (ETDEWEB)

    Sucharova, Julie; Suchara, Ivan; Hola, Marie [Silva Tarouca Research Institute for Landscape and Ornamental Gardening, Kvetnove namesti 391, 252 43 Pruhonice (Czech Republic); Reimann, Clemens, E-mail: Clemens.Reimann@ngu.no [Geological Survey of Norway, P.O. Box 6315 Sluppen, 7491 Trondheim (Norway); Boyd, Rognvald [Geological Survey of Norway, P.O. Box 6315 Sluppen, 7491 Trondheim (Norway); Filzmoser, Peter [Institute for Statistics and Probability Theory, Vienna University of Technology, Wiedner Hauptstrasse 8-10, 1040 Wien (Austria); Englmaier, Peter [Faculty of Life Science, University of Vienna, Althanstr. 14, A-1090 Vienna (Austria)

    2011-05-15

    While terrestrial moss and other plants are frequently used for environmental mapping and monitoring projects, data on the regional geochemistry of humus are scarce. Humus, however, has a much larger life span than any plant material. It can be seen as the 'environmental memory' of an area for at least the last 60-100 years. Here concentrations of 39 elements determined by ICP-MS and ICP AES, pH and ash content are presented for 259 samples of forest floor humus collected at an average sample density of 1 site/300 km{sup 2} in the Czech Republic. The scale of anomalies linked to known contamination sources (e.g., lignite mining and burning, metallurgical industry, coal fired power plants, metal smelters) is documented and discussed versus natural processes influencing humus quality. Most maps indicate a local impact from individual contamination sources: often more detailed sampling than used here would be needed to differentiate between likely sources. - Highlights: > Concentrations of 39 elements in forest floor humus are provided. > The capabilities of humus sampling for bio-monitoring purposes are demonstrated. > Geochemical anomalies are linked to known contamination sources. > The study shows the importance of scale for geochemical mapping projects. > Humus provides a picture of the long term contamination history of a country. - Forest floor humus, the atmosphere-biosphere-pedosphere interface, archives an environmental contamination signal over long time periods.

  4. Spatial and vertical distribution of mercury in upland forest soils across the northeastern United States

    International Nuclear Information System (INIS)

    Richardson, Justin B.; Friedland, Andrew J.; Engerbretson, Teresa R.; Kaste, James M.; Jackson, Brian P.

    2013-01-01

    Assessing current Hg pools in forest soils of the northeastern U.S. is important for monitoring changes in Hg cycling. The forest floor, upper and lower mineral horizons were sampled at 17 long-term upland forest sites across the northeastern U.S. in 2011. Forest floor Hg concentration was similar across the study region (274 ± 13 μg kg −1 ) while Hg amount at northern sites (39 ± 6 g ha −1 ) was significantly greater than at western sites (11 ± 4 g ha −1 ). Forest floor Hg was correlated with soil organic matter, soil pH, latitude and mean annual precipitation and these variables explained approximately 70% of the variability when multiple regressed. Mercury concentration and amount in the lower mineral soil was correlated with Fe, soil organic matter and latitude, corresponding with Bs horizons of Spodosols (Podzols). Our analysis shows the importance of regional and soil properties on Hg accumulation in forest soils. -- Highlights: •Mercury in the forest floor and mineral soil was quantified at 17 sites. •Concentrations and amounts were regressed with regional factors and soil properties. •Forest floor Hg was most explained by soil organic matter, pH, and precipitation. •Mineral soil Hg was explained by latitude, Fe concentration, and soil organic matter. •Mineral soil Hg was greatest in Bs horizons of Spodosols due to podzolization. -- Forest floor Hg was correlated with soil organic matter, pH, latitude, and mean annual precipitation. Mineral soil Hg was greatest in Bs horizons of Spodosols

  5. Carbon dioxide flux measurements from a coastal Douglas-fir forest floor

    International Nuclear Information System (INIS)

    Drewitt, G.B.

    2002-01-01

    This thesis examined the process that affects the exchange of carbon between the soil and the atmosphere with particular attention to the large amounts of carbon stored in soils in the form of decaying organic matter. This forest floor measuring study was conducted in 2000 at a micro-meteorological tower flux site in a coastal temperature Douglas-fir forest. The measuring study involved half hourly measurements of both carbon dioxide and below-ground carbon dioxide storage. Measurements were taken at 6 locations between April and December to include a large portion of the growing season. Eddy covariance (EC) measurements of carbon dioxide flux above the forest floor over a two month period in the summer and the autumn were compared with forest floor measurements. Below-ground carbon dioxide mixing ratios of soil air were measured at 6 depths between 0.02 to 1 m using gas diffusion probes and a syringe sampling method. Maximum carbon dioxide fluxes measured by the soil chambers varied by a factor of 3 and a high spatial variability in soil carbon dioxide flux was noted. Forest floor carbon dioxide fluxes measured by each of the chambers indicated different sensitivities to soil temperature. Hysteresis in the flux temperature relationship over the year was evident. Reliable below-canopy EC measurements of the forest floor carbon dioxide flux were difficult to obtain because of the every low wind speeds below the forest canopy. The amount of carbon dioxde present in the soil increased rapidly with depth near the surface but less rapidly deeper in the soil. It was suggested that approximately half of the carbon dioxide produced below-ground comes from between the soil surface and the first 0.15 m of depth. Carbon dioxide fluxes from the floor of a Douglas-fir forest were found to be large compared to other, less productive ecosystems

  6. The distribution of nitrogen and phosphorus in forest floor layers of oak-hickory forests of varying productivity

    Science.gov (United States)

    Karyn S. Rodkey; Donald J. Kaczmarek; Phillip E. Pope

    1995-01-01

    The forest floor plays a major role in the storage and recycling of nutrients which, in turn, are important in maintaining the growth and productivity of forest ecosystems. The development of forest floor organic layers as influenced by litter quality and site quality is unclear. Previous studies in this lab have shown that the size and distribution of available...

  7. Carbon and nitrogen in forest floor and mineral soil under six common European tree species

    DEFF Research Database (Denmark)

    Vesterdal, Lars; Schmidt, Inger K.; Callesen, Ingeborg

    2007-01-01

    The knowledge of tree species effects on soil C and N pools is scarce, particularly for European deciduous tree species. We studied forest floor and mineral soil carbon and nitrogen under six common European tree species in a common garden design replicated at six sites in Denmark. Three decades...... on forest floor C and N content was primarily attributed to large differences in turnover rates as indicated by fractional annual loss of forest floor C and N. The C/N ratio of foliar litterfall was a good indicator of forest floor C and N contents, fractional annual loss of forest floor C and N...

  8. Contribution of forest floor fractions to carbon storage and ...

    African Journals Online (AJOL)

    Forest floor carbon stocks, which include different components of litter, hemic and sapric materials, have not been empirically quantified in tropical montane forest, although they influence soil carbon (C) pools. To date, the contribution of arbuscular mycorrhizae in C sequestration potentials in tropical montane forests have ...

  9. Spatial distribution of lead and lead isotopes in soil B-horizon, forest-floor humus, grass (Avenella flexuosa) and spruce (Picea abies) needles across the Czech Republic

    Energy Technology Data Exchange (ETDEWEB)

    Sucharova, Julie; Suchara, Ivan [Silva Tarouca Research Institute for Landscape and Ornamental Gardening, Kvetnove namesti 391, 252 43 Pruhonice (Czech Republic); Reimann, Clemens, E-mail: Clemens.Reimann@ngu.no [Geological Survey of Norway, P.O. Box 6315 Sluppen, 7491 Trondheim (Norway); Boyd, Rognvald [Geological Survey of Norway, P.O. Box 6315 Sluppen, 7491 Trondheim (Norway); Filzmoser, Peter [Institute for Statistics and Probability Theory, Vienna University of Technology, Wiedner Hauptstrasse 8-10, 1040 Wien (Austria); Englmaier, Peter [Faculty of Life Science, University of Vienna, Althanstr. 14, A-1090 Vienna (Austria)

    2011-07-15

    Highlights: > Pb-concentrations and {sup 206}Pb/{sup 207}Pb isotope ratios are provided for four different sample materials for the Czech Republic. > The paper demonstrates the local impact of a number of different contamination sources. > The data provide clear evidence that traffic emissions are no major source of Pb to the Czech environment. > The data demonstrate that the B-horizon provides no valid 'background' for Pb-concentration or the {sup 206}Pb/{sup 207}Pb isotope ratio. > Pb isotope ratios change during soil weathering and at the interface biosphere/pedosphere. - Abstract: Lead concentrations were determined in samples of soil B-horizon (N = 258), forest-floor humus (O-horizon, N = 259), grass (Avenella flexuosa, N = 251) and spruce (Picea abies, N = 253) needles (2nd year) collected at the same locations evenly spread over the territory of the Czech Republic at an average density of 1 site/300 km{sup 2}. Median Pb concentrations differ widely in the four materials: soil B-horizon: 27 mg/kg (3.3-220 mg/kg), humus: 78 mg/kg (19-1863 mg/kg), grass: 0.37 mg/kg (0.08-8 mg/kg) and spruce needles: 0.23 mg/kg (0.07-3 mg/kg). In the Pb distribution maps for humus, grass and spruce a number of well-known Pb-contamination sources are indicated by unusually high concentrations (e.g., the Pb smelter at Pribram, the metallurgical industry in the NE of the Czech Republic and along the Polish border, as well as the metallurgical industry in Upper Silesia and Europe's largest coal-fired power plant at Bogatynia, Poland). The ratio {sup 206}Pb/{sup 207}Pb was determined in all four materials. The median value of the {sup 206}Pb/{sup 207}Pb isotope ratio in the soil B-horizon is 1.184 (variation: 1.145-1.337). In both humus and grass the median value for the {sup 206}Pb/{sup 207}Pb isotope ratio is 1.162 (variation: 1.130-1.182), in spruce needles the median ratio is 1.159 (variation: 1.116-1.186). In humus, grass and spruce needles the known contamination

  10. The role of litterfall in transferring Fukushima-derived radiocesium to a coniferous forest floor

    Energy Technology Data Exchange (ETDEWEB)

    Teramage, Mengistu T., E-mail: teramaget@yahoo.com [Center for Research in Isotopes and Environmental Dynamics, University of Tsukuba, Tennodai 1-1-1, Tsukuba shi, Ibaraki 305-8572 (Japan); Onda, Yuichi; Kato, Hiroaki [Center for Research in Isotopes and Environmental Dynamics, University of Tsukuba, Tennodai 1-1-1, Tsukuba shi, Ibaraki 305-8572 (Japan); Gomi, Takashi [Department of International Environmental and Agricultural Science, Tokyo University of Agriculture and Technology, Fuchuu, Tokyo 183-8509 (Japan)

    2014-08-15

    The deposition of Fukushima-derived radiocesium via falling litter in a coniferous forest 180 km downwind immediately following the nuclear power plant accident was investigated. The litterfall contribution to the transfer of radiocesium from the forest canopy to the forest floor was determined, and this pathway was compared with hydrological pathways. The results demonstrated that during the observation period, a total of approximately 5.5 kBq m{sup −2} of Fukushima-derived radiocesium was deposited on the forest floor through throughfall (53%), stemflow (2.3%) and litterfall (45%) routes. The data revealed that the contributions of hydrological pathways became less important as time passed. However, the litterfall route, which transferred approximately 31% (2.5 ± 0.6 kBq m{sup −2}) of the local fallout within the observation period, continued depositing radiocesium onto the forest floor. - Graphical abstract: Schematic diagram summarizing the depositional routes of radiocesium in the cypress forest during the observation period (March to October, 2011). - Highlights: • Fukushima-derived radiocesium deposition in a coniferous forest was explored. • Approximately 68% of the radiocesium was deposited onto the forest floor. • The ecological half-life of the radiocesium in the forest canopy was 180 days. • The roles of hydrological pathways decreased over time. • The litterfall route continued to deposit radiocesium onto the forest floor.

  11. Fluxes of inorganic and organic arsenic species in a Norway spruce forest floor

    Energy Technology Data Exchange (ETDEWEB)

    Huang, J.-H. [Department of Soil Ecology, University of Bayreuth, D-95440 Bayreuth (Germany)], E-mail: jenhow.huang@uni-bayreuth.de; Matzner, Egbert [Department of Soil Ecology, University of Bayreuth, D-95440 Bayreuth (Germany)

    2007-09-15

    To identify the role of the forest floor in arsenic (As) biogeochemistry, concentrations and fluxes of inorganic and organic As in throughfall, litterfall and forest floor percolates at different layers were investigated. Nearly 40% of total As{sub total} input (5.3 g As ha{sup -1} yr{sup -1}) was retained in Oi layer, whereas As{sub total} fluxes from Oe and Oa layers exceeded the input by far (10.8 and 20 g As ha{sup -1} yr{sup -1}, respectively). Except dimethylarsinic acid (DMA), fluxes of organic As decreased with depth of forest floor so that <10% of total deposition (all <0.3 g As ha{sup -1} yr{sup -1}) reached the mineral soil. All forest floor layers are sinks for most organic As. Conversely, Oe and Oa layers are sources of As{sub total}, arsenite, arsenate and DMA. Significant correlations (r {>=} 0.43) between fluxes of As{sub total}, arsenite, arsenate or DMA and water indicate hydrological conditions and adsorption-desorption as factors influencing their release from the forest floor. The higher net release of arsenite from Oe and Oa and of DMA from Oa layer in the growing than dormant season also suggests microbial influences on the release of arsenite and DMA. - The forest floor layers are generally a source for inorganic arsenic species but a sink for most organic arsenic species under the present deposition rate.

  12. The distribution of mercury in a forest floor transect across the central United States

    Science.gov (United States)

    Charles H. (Hobie) Perry; Michael C. Amacher; William Cannon; Randall K. Kolka; Laurel Woodruff

    2009-01-01

    Mercury (Hg) stored in soil organic matter may be released when the forest floor is consumed by fire. Our objective is to document the spatial distribution of forest floor Hg for a transect crossing the central United States. Samples collected by the Forest Service, U.S. Department of Agriculture's Forest Inventory and Analysis Soil Quality Indicator were tested...

  13. Gaseous mercury fluxes from the forest floor of the Adirondacks

    International Nuclear Information System (INIS)

    Choi, Hyun-Deok; Holsen, Thomas M.

    2009-01-01

    The flux of gaseous elemental mercury (Hg 0 ) from the forest floor of the Adirondack Mountains in New York (USA) was measured numerous times throughout 2005 and 2006 using a polycarbonate dynamic flux chamber (DFC). The Hg flux ranged between -2.5 and 27.2 ng m -2 h -1 and was positively correlated with temperature and solar radiation. The measured Hg emission flux was highest in spring, and summer, and lowest in winter. During leaf-off periods, the Hg emission flux was highly dependent on solar radiation and less dependent on temperature. During leaf-on periods, the Hg emission flux was fairly constant because the forest canopy was shading the forest floor. Two empirical models were developed to estimate yearly Hg 0 emissions, one for the leaf-off period and one for the leaf-on period. Using the U.S. EPA's CASTNET meteorological data, the cumulative estimated emission flux was approx. 7.0 μg Hg 0 m -2 year -1 . - Empirical models based on the Hg emission measurements from the forest floor of the Adirondacks indicate the estimated emission flux was approx. 7.0 μg Hg 0 m -2 year -1 in 2006

  14. Transforming Pinus pinaster forest to recreation site: preliminary effects on LAI, some forest floor, and soil properties.

    Science.gov (United States)

    Öztürk, Melih; Bolat, İlyas

    2014-04-01

    This study investigates the effects of forest transformation into recreation site. A fragment of a Pinus pinaster plantation forest was transferred to a recreation site in the city of Bartın located close to the Black Sea coast of northwestern Turkey. During the transformation, some of the trees were selectively removed from the forest to generate more open spaces for the recreationists. As a result, Leaf Area Index (LAI) decreased by 0.20 (about 11%). Additionally, roads and pathways were introduced into the site together with some recreational equipment sealing parts of the soil surface. Consequently, forest environment was altered with a semi-natural landscape within the recreation site. The purpose of this study is to assess the effects of forest transformation into recreation site particularly in terms of the LAI parameter, forest floor, and soil properties. Preliminary monitoring results indicate that forest floor biomass is reduced by 26% in the recreation site compared to the control site. Soil temperature is increased by 15% in the recreation site where selective removal of trees expanded the gaps allowing more light transmission. On the other hand, the soil bulk density which is an indicator of soil compaction is unexpectedly slightly lower in the recreation site. Organic carbon (C(org)) and total nitrogen (N(total)) together with the other physical and chemical parameter values indicate that forest floor and soil have not been exposed to much disturbance. However, subsequent removal of trees that would threaten the vegetation, forest floor, and soil should not be allowed. The activities of the recreationists are to be concentrated on the paved spaces rather than soil surfaces. Furthermore, long-term monitoring and management is necessary for both the observation and conservation of the site.

  15. Distribution of black carbon in ponderosa pine forest floor and soils following the High Park wildfire

    Science.gov (United States)

    Boot, C. M.; Haddix, M.; Paustian, K.; Cotrufo, M. F.

    2015-05-01

    Biomass burning produces black carbon (BC), effectively transferring a fraction of the biomass C from an actively cycling pool to a passive C pool, which may be stored in the soil. Yet the timescales and mechanisms for incorporation of BC into the soil profile are not well understood. The High Park fire (HPF), which occurred in northwestern Colorado in the summer of 2012, provided an opportunity to study the effects of both fire severity and geomorphology on properties of carbon (C), nitrogen (N) and BC in the Cache La Poudre River drainage. We sampled montane ponderosa pine forest floor (litter plus O-horizon) and soils at 0-5 and 5-15 cm depth 4 months post-fire in order to examine the effects of slope and burn severity on %C, C stocks, %N and BC. We used the benzene polycarboxylic acid (BPCA) method for quantifying BC. With regard to slope, we found that steeper slopes had higher C : N than shallow slopes but that there was no difference in BPCA-C content or stocks. BC content was greatest in the forest floor at burned sites (19 g BPCA-C kg-1 C), while BC stocks were greatest in the 5-15 cm subsurface soils (23 g BPCA-C m-2). At the time of sampling, unburned and burned soils had equivalent BC content, indicating none of the BC deposited on the land surface post-fire had been incorporated into either the 0-5 or 5-15 cm soil layers. The ratio of B6CA : total BPCAs, an index of the degree of aromatic C condensation, suggested that BC in the 5-15 cm soil layer may have been formed at higher temperatures or experienced selective degradation relative to the forest floor and 0-5 cm soils. Total BC soil stocks were relatively low compared to other fire-prone grassland and boreal forest systems, indicating most of the BC produced in this system is likely lost, either through erosion events, degradation or translocation to deeper soils. Future work examining mechanisms for BC losses from forest soils will be required for understanding the role BC plays in the global

  16. Radiation budget, soil heat flux and latent heat flux at the forest floor in warm, temperate mixed forest

    International Nuclear Information System (INIS)

    Tamai, K.; Abe, T.; Araki, M.; Ito, H.

    1998-01-01

    Seasonal changes in the radiation budget and soil heat flux of a forest floor were measured in a mixed forest located in Kyoto, Japan. The basal area at breast height in the survey forest was about 15·82 m 2 ha −1 , for evergreen trees, and 12·46 m 2 ha −1 , for deciduous trees. The sky view factor was 16 and 22% at the survey site in the foliate and defoliate seasons, respectively. The small difference between the sky view factor in the two seasons was reflected in the seasonal change in the radiation budget of the forest floor. Namely, the net long-wave radiation changed rapidly in leafing and falling days, and the rate of net short-wave radiation was highest in April. The distinctive characteristic of the radiation budget was that the rates of available radiation in the daytime and at night were almost equal in September and October. Latent heat flux at the forest floor was estimated to be around 94 MJ m −2 annually, from our measurement with the simulation model. (author)

  17. Impacts of invasive earthworms on soil mercury cycling: Two mass balance approaches to an earthworm invasion in a northern Minnesota forest

    Science.gov (United States)

    Sona Psarska; Edward A. Nater; Randy Kolka

    2016-01-01

    Invasive earthworms perturb natural forest ecosystems that initially developed without them, mainly by consuming the forest floor (an organic rich surficial soil horizon) and by mixing the upper parts of the soil. The fate of mercury (Hg) formerly contained in the forest floor is largely unknown. We used two mass balance approaches (simple mass balance and geochemical...

  18. Linking chemical elements in forest floor humus (Oh-horizon) in the Czech Republic to contamination sources.

    Science.gov (United States)

    Sucharova, Julie; Suchara, Ivan; Hola, Marie; Reimann, Clemens; Boyd, Rognvald; Filzmoser, Peter; Englmaier, Peter

    2011-05-01

    While terrestrial moss and other plants are frequently used for environmental mapping and monitoring projects, data on the regional geochemistry of humus are scarce. Humus, however, has a much larger life span than any plant material. It can be seen as the "environmental memory" of an area for at least the last 60-100 years. Here concentrations of 39 elements determined by ICP-MS and ICP AES, pH and ash content are presented for 259 samples of forest floor humus collected at an average sample density of 1 site/300 km2 in the Czech Republic. The scale of anomalies linked to known contamination sources (e.g., lignite mining and burning, metallurgical industry, coal fired power plants, metal smelters) is documented and discussed versus natural processes influencing humus quality. Most maps indicate a local impact from individual contamination sources: often more detailed sampling than used here would be needed to differentiate between likely sources. Copyright © 2011 Elsevier Ltd. All rights reserved.

  19. The effect of organic acids on base cation leaching from the forest floor under six North American tree species

    NARCIS (Netherlands)

    Dijkstra, F.A.; Geibe, C.; Holmstrom, S.; Lundstrom, U.S.; Breemen, van N.

    2001-01-01

    Organic acidity and its degree of neutralization in the forest floor can have large consequences for base cation leaching under different tree species. We investigated the effect of organic acids on base cation leaching from the forest floor under six common North American tree species. Forest floor

  20. Invasive and exotic earthworms: an unaccounted change to mercury cycling in northeastern US forest soils

    Science.gov (United States)

    Richardson, J. B.; Friedland, A. J.; Görres, J. H.; Renock, D. J.; Jackson, B. P.

    2014-12-01

    Invasive and exotic earthworms are now present in many forested areas of the northeastern US with currently unquantified consequences to abiotic and biotic Hg cycling. To quantify these effects, we measured Hg concentrations (mg kg-1) and amounts (μg m-2) in earthworms and soil horizons at 45 soil pits from 9 sites in northern New England. Seven earthworm species were observed in varying assemblages. Most earthworm species attained concentrations of Hg potentially hazardous to wildlife that may ingest them, with highest concentrations found in shallow-burrowing, litter-feeders. Specifically, Aporrectodea rosea and Amynthas agrestis had the greatest Hg concentrations (0.9 ± 0.1) and Hg amounts (8 ± 2) μg m-2. Aporrectodea rosea and Amynthas agrestis were found to inhabit the forest floor and the top 5 cm of the mineral horizons in high abundance, potentially making it a readily accessible prey species. Bioaccumulation of Hg by invasive and exotic earthworms may be an important mechanism that transfers Hg to ground foraging predators, such as thrushes, red-backed salamanders and foxes, which is generally unaccounted for in terrestrial food chains. Earthworm Hg concentrations were poorly correlated with their respective soil Hg concentrations, suggesting a species dependence for Hg bioaccumulation rather than site effects. We observed that forest floor Hg concentrations and amounts were 23% and 57% lower, respectively, at soil pits with earthworms compared to those without. Moreover, Hg amounts in forest floor-feeding earthworms exceeded the remaining forest floor Hg pools. Mercury concentrations and pools in the mineral soil were 21% and 33% lower, respectively, for soil pits with earthworms compared to those without. We hypothesize that enhanced decomposition, horizon disturbance and bioaccumulation by earthworms has decreased Hg amounts in the forest floor and mineral soil. Our results suggest that earthworms are decreasing Hg storage in forest soils with

  1. Linking chemical elements in forest floor humus (O-h-horizon) in the Czech Republic to contamination sources

    Energy Technology Data Exchange (ETDEWEB)

    Sucharova, J.; Suchara, I.; Hola, M.; Reimann, C.; Boyd, R.; Filzmoser, P.; Englmaier, P. [Geological Survey of Norway, Trondheim (Norway)

    2011-05-15

    While terrestrial moss and other plants are frequently used for environmental mapping and monitoring projects, data on the regional geochemistry of humus are scarce. Humus, however, has a much larger life span than any plant material. It can be seen as the 'environmental memory' of an area for at least the last 60-100 years. Here concentrations of 39 elements determined by ICP-MS and ICP AES, pH and ash content are presented for 259 samples of forest floor humus collected at an average sample density of 1 site/300 km{sup 2} in the Czech Republic. The scale of anomalies linked to known contamination sources (e.g., lignite mining and burning, metallurgical industry, coal fired power plants, metal smelters) is documented and discussed versus natural processes influencing humus quality. Most maps indicate a local impact from individual contamination sources: often more detailed sampling than used here would be needed to differentiate between likely sources.

  2. Soil organic matter composition and quality across fire severity gradients in coniferous and deciduous forests of the southern boreal region

    Science.gov (United States)

    Miesel, Jessica R.; Hockaday, William C.; Kolka, Randall K.; Townsend, Philip A.

    2015-06-01

    Recent patterns of prolonged regional drought in southern boreal forests of the Great Lakes region, USA, suggest that the ecological effects of disturbance by wildfire may become increasingly severe. Losses of forest soil organic matter (SOM) during fire can limit soil nutrient availability and forest regeneration. These processes are also influenced by the composition of postfire SOM. We sampled the forest floor layer (i.e., full organic horizon) and 0-10 cm mineral soil from stands dominated by coniferous (Pinus banksiana Lamb.) or deciduous (Populus tremuloides Michx.) species 1-2 months after the 2011 Pagami Creek wildfire in northern Minnesota. We used solid-state 13C NMR to characterize SOM composition across a gradient of fire severity in both forest cover types. SOM composition was affected by fire, even when no statistically significant losses of total C stocks were evident. The most pronounced differences in SOM composition between burned and unburned reference areas occurred in the forest floor for both cover types. Carbohydrate stocks in forest floor and mineral horizons decreased with severity level in both cover types, whereas pyrogenic C stocks increased with severity in the coniferous forest floor and decreased in only the highest severity level in the deciduous forest floor. Loss of carbohydrate and lignin pools contributed to a decreased SOM stability index and increased decomposition index. Our results suggest that increases in fire severity expected to occur under future climate scenarios may lead to changes in SOM composition and dynamics with consequences for postfire forest recovery and C uptake.

  3. Forest Floor Carbon Exchange of a Boreal Black Spruce Forest in Eastern Canada

    Science.gov (United States)

    Bergeron, O.; Margolis, H. A.; Coursolle, C.

    2009-06-01

    This study reports continuous automated measurements of forest floor carbon (C) exchange over feathermoss, lichen, and sphagnum micro-sites in a black spruce forest in eastern North America during snow-free periods over three years. The response of soil respiration (Rs-auto) and forest floor photosynthesis (Pff) to environmental factors was determined. The seasonal contributions of scaled up Rs-auto adjusted for spatial representativeness (Rs-adj) and Pff (Pff-eco) relative to that of total ecosystem respiration (Re) and photosynthesis (Peco), respectively, were also quantified. Shallow soil temperature explained 67-86% of the variation in Rs-auto for all ground cover types, while deeper soil temperatures were related to Rs-auto only for the feathermoss micro-sites. Base respiration was consistently lower under feathermoss, intermediate under sphagnum, and higher under lichen during all three years. The Rs-adj/Re ratio increased from spring through autumn and ranged from 0.85 to 0.87 annually for the snow-free period. The Rs-adj/Re ratio was negatively correlated with the difference between air and shallow soil temperature and this correlation was more pronounced in autumn than summer and spring. Maximum photosynthetic capacity of the forest floor (Pffmax) saturated at low irradiance levels (~200 μmol m-2 s-1) and decreased with increasing air temperature and vapor pressure deficit for all three ground cover types, suggesting that Pff was more limited by desiccation than by light availability. Pffmax was lowest for sphagnum, intermediate for feathermoss, and highest for lichen for two of the three years. Pff normalized for light peaked at air temperatures of 5-8°C, suggesting that this is the optimal temperature range for Pff. The Pff-eco/Peco ratio varied seasonally from 13 to 24% and reached a minimum in mid-summer when both air temperature and Peco were at their maximum. On an annual basis, Pff-eco accounted for 17-18% of Peco depending on the year and the

  4. A climate response function explaining most of the variation in the forest floor needle mass and the needle decomposition in pine forests across Europe

    DEFF Research Database (Denmark)

    Kurz-Besson, C.; Coûteaux, M.M.; Berg, Bjørn

    2006-01-01

    The forest floor needle mass and the decomposition rates of pine needle litter in a European climate transect were studied in order to estimate the impact of climate change on forest soil carbon sequestration. Eight pine forests preserved from fire were selected along a climatic latitudinal...... gradient from 40° to 60° N, from Spain and Portugal to Sweden. The forest floor (Oi and Oe layers) was sorted into five categories of increasing decomposition level according to morphological criteria. The needle mass loss in each category was determined using a linear mass density method. The needle...... and a recalcitrant one. NF was correlated with actual evapotranspiration (AET) whereas the decomposition parameters (decomposition rate of the decomposable fraction, first year mass loss, forest floor needle mass, age of the most-decomposed category) were related to a combined response function to climate (CRF...

  5. [Characteristics of floor litter and soil arthropod community in different types ot subtropical forest in Ailao Mountain of Yunnan, Southwest China].

    Science.gov (United States)

    Yang, Zhao; Yang, Xiao-Dong

    2011-11-01

    By using line transect method, an investigation was conducted on the floor litter and soil arthropod community in a mid mountain wet evergreen broad-leaved forest, a mossy dwarf forest, and a Populus bonatii forest in Ailao Mountain of Yunnan in April (dry and hot season), June (rainy season), and December (dry and cold season), 2005. In both dry and rainy seasons, the existing floor litter mass, C storage, and C/N ratio in the three forests all increased in the order of mossy dwarf forest > P. bonatii forest > evergreen broad-leaved forest, but the N storage had less difference. In the floor litter layer of the forests, Acari and Collembola were the dominant groups of soil arthropod community, while Diptera larvae, Coleoptera, ants, and Homoptera were the common groups. The Sorenson coefficients of soil arthropod community in the three forests were extremely great. No significant differences were observed in the soil arthropod density (ind x m(-2)) in the floor litter layer among the three forests, but the relative density (ind x g(-1)) of soil arthropods was higher in the evergreen broad-leaved forest and P. bonatii forest than in the mossy dwarf forest. In the three forests, the density of soil arthropods was significantly higher in dry season than in rainy season, but the Shannon diversity index had less difference. There were significant positive correlations between the existing floor litter mass and the individual density (ind x m(-2)) and dominant groups of soil arthropod communities in dry and hot season (April), but negative correlations between the existing floor litter mass and the relative density (ind x g(-1)) of soil arthropod communities and Acari in dry and cold season (December). The individual densities of Collembola and Coleoptera also had positive correlations with the N storage of the existing floor litter mass in the three forests. It was considered that the floor litter and the development of soil arthropod community in the litter layer of

  6. Post-fire comparisons of forest floor and soil carbon, nitrogen, and mercury pools with fire severity indices

    Science.gov (United States)

    Randy Kolka; Brian Sturtevant; Philip Townsend; Jessica Miesel; Peter Wolter; Shawn Fraver; Tom DeSutter

    2014-01-01

    Forest fires are important contributors of C, N, and Hg to the atmosphere. In the fall of 2011, a large wildfire occurred in northern Minnesota and we were able to quickly access the area to sample the forest floor and mineral soil for C, N, and Hg pools. When compared with unburned reference soils, the mean loss of C resulting from fire in the forest floor and the...

  7. Trace gas exchange above the floor of a deciduous forest: 1. Evaporation and CO2 efflux

    Science.gov (United States)

    Baldocchi, Dennis D.; Meyers, Tilden P.

    1991-04-01

    The eddy correlation method has great potential for directly measuring trace gas fluxes at the floor of a forest canopy, but a thorough validation study has not been yet conducted. Another appeal of the eddy correlation method is its ability to study processes that regulate and modulate gas exchange between the soil/litter complex and the atmosphere that cannot be probed with chambers. In this paper we report on eddy correlation measurements of water vapor, sensible heat, and carbon dioxide exchange that were made at the floor of a deciduous forest. The validity of the eddy correlation method to measure the emission of water vapor and CO2 from a deciduous forest floor is demonstrated by our ability to close the surface energy budget during periods that meet the requirements of the technique. Water vapor fluxes from a dry forest floor are strongly influenced by large-scale turbulent events that penetrate deep into the canopy. The frequency of these turbulent events prevents equilibrium evaporation rates from being achieved because the dynamic time constant for water vapor exchange is longer. Consequently, maximal evaporation rates are capped to rates defined by the product of the driving potential of the atmosphere and the surface conductance. On the other hand, evaporation from a wet forest floor proceeds at rates reaching or exceeding equilibrium evaporation and are highly correlated with static pressure fluctuations. CO2 efflux rates are governed by litter and soil temperature, as expected. But we also find a significant correlation between static pressure fluctuations and soil/litter CO2 exchange rates.

  8. Inferred effects of cloud deposition on forest floor nutrient cycling and microbial properties along a short elevation gradient

    International Nuclear Information System (INIS)

    Lavoie, M.; Bradley, R.L.

    2003-01-01

    Higher cloud cover significantly decreases forest floor pH, decrease exchangeable cations, modifies mineral-N speciation and increases physiological stress within microbial communities. - Cloud water deposition often increases with elevation, and it is widely accepted that this cloud water increases acid loading to upland forest ecosystems. A study was undertaken in south-eastern Quebec to determine if a 250 m elevation gradient (i.e. 420-665 m), along a uniform sugar-maple stand on the slope of Mount Orford, corresponded to a pH gradient in the forest floor and to predictable changes in soil nutrient availability and microbial properties. Precipitation data from a nearby study, and a photographic survey, provided presumptive evidence that this elevation gradient corresponded to a strong gradient in cloud water deposition. Forest floor temperature did not differ significantly across elevations. Forest floor moisture content was significantly higher, whereas pH and exchangeable Ca and Mg were significantly lower, at the higher elevations. Average seasonal net nitrification rates, determined by long-term laboratory incubations, did not differ significantly across elevations, whereas average seasonal net ammonification rates were significantly higher at higher elevations. Basal respiration rates and microbial biomass did not differ significantly across elevations, but metabolic quotient was significantly higher at higher elevations indicating possible environmental stress on forest floor microbial communities due to cloud water deposition. Anaerobic N mineralisation rates were significantly higher at higher elevations suggesting that N-limited microbial communities frequently exposed to cloud cover can be important short-term sinks for atmospheric N, thereby contributing to increase the active-N fraction of forest floors. We conclude that, where no significant changes in vegetation or temperature occur, elevation gradients can still be used to understand the spatial

  9. Radiocesium in forest ecosystems in South Bohemia

    International Nuclear Information System (INIS)

    Uhlířová, H.; Konečný, J.

    1994-01-01

    Radiocaesium accumulation in spruce needles, forest floor horizons, lichens, mosses, mushrooms and bilberry shrubs was measured in the South Bohemia region before setting the nuclear power plant Temelin into operation. Radiocaesium accumulated mainly in decomposed forest floor horizons, mosses, lichens and some species of mushrooms. Plots at a higher altitude with higher rainfall amounts showed the increased levels of both 134Cs and 137Cs activity in all treated compartments of forest ecosystem. 137Cs in forest floor accumulated in most decomposed horizons H (0.29-1.95) and L+F (0.21-1.08 Bq.g-1). Lower activity was detected in the upper 3-5 cm of mineral soil (0.01-0.41 Bq.g-1). 134Cs activity which is unambiguously of Chernobyl origin ranged between 0.03 and 0.11 Bq.g-1 in the L+F horizon and between 0.03 and 0.16 Bq.g-1 in the H horizon. In the A horizon no activity of 134Cs was detected. Specific activities of radiocaesium in mushrooms collected in July 1992 only on two plots showed great differences between species and localities. 137Cs activity in one-year-old spruce needles ranged between 0.05 and 0.26 Bq.g-1. It was not detectable on sample plots Podhaji, Kaliste and Strouha. 134Cs activity was very often under detection limit except the plots Zdikov (0.03 Bq.g-1) and Hnevkovice (0.01 Bq.g-1). The lower activity of 137Cs in 1991 and 1992 should be due to summer and winter droughts. Specific activity of radiocaesium and sum-beta activity in ash from bilberry shrubs was higher in samples collected in the open area than in those under canopies, except the Zdikov plot. Lichens are very good ecological bioindicatores of radiocaesium deposition, among them on study plots the best was Parmelia spec. Comparative measurements of 137Cs activity in different mosses on two plots with a higher radioactive background showed the high accumulation of radiocaesium in Dicranum scoparium and Sphagnum spec. The accumulation of beta-counting radionuclides in Dicranum scoparium

  10. Microhabitat effects of litter temperature and moisture on forest-floor invertebrate communities

    Science.gov (United States)

    Tim A. Christiansen; Sue A. Perry; William B. Perry

    1996-01-01

    Litter temperature and moisture may be altered due to changes in global climate. We investigated the effect of small changes in litter temperature and moisture on forest-floor communities in West Virginia.

  11. Carbon and nitrogen accumulation in forest floor and surface soil under different geographic origins of Maritime pine (Pinus pinaster Aiton.) plantations

    Energy Technology Data Exchange (ETDEWEB)

    Ozdemir, E.; Oral, H. V.; Akburak, S.; Makineci, E.; Yilmaz, E.

    2013-09-01

    Aim of study: To determine if plantations consisting of different geographic origins of the Maritime pine (Pinus pinaster Aiton.) could have altered C and N stocks in the forest floor and surface soils. Area of study: Forest floor and mineral soil C and N stocks were measured in four adjacent plantations of different geographic origins of Maritime pine (Gironde, Toulon, Corsica and Spain) and adjacent primary native Sessile oak (Quercus petraea L.) at Burunsuz region in Belgrad Forest where is located in the Istanbul province in the Marmara geographical region between 41° 09’-41° 12’ N latitude and 28° 54’-29° 00’ E longitude in Turkey. Material and methods: Plots were compared as common garden experiments without replications. 15 surface soil (0-10 cm) and 15 forest floor samples were taken from each Maritime pine origins and adjacent native Sessile oak forest. C and N contents were determined on LECO Truspec 2000 CN analyzer. The statistical significance of the results was evaluated by one-way Analysis of Variance (ANOVA). Research highlights: Forest floor carbon mass, nitrogen concentration and nitrogen mass of forest floor showed a significant difference among origins. Soil carbon mass and nitrogen mass did not significantly differ among investigated plots. (Author)

  12. Forest floor carbon exchange of a boreal black spruce forest in eastern North America

    Science.gov (United States)

    Bergeron, O.; Margolis, H. A.; Coursolle, C.

    2009-09-01

    This study reports continuous automated measurements of forest floor carbon (C) exchange over feathermoss, lichen, and sphagnum micro-sites in a black spruce forest in eastern North America during snow-free periods over three years. The response of soil respiration (Rs-auto) and forest floor photosynthesis (Pff) to environmental factors was determined. The seasonal contributions of scaled up Rs-auto adjusted for spatial representativeness (Rs-adj) and Pff (Pff-eco) relative to that of total ecosystem respiration (Re) and photosynthesis (Peco), respectively, were also quantified. Shallow (5 cm) soil temperature explained 67-86% of the variation in Rs-auto for all ground cover types, while deeper (50 and 100 cm) soil temperatures were related to Rs-auto only for the feathermoss micro-sites. Base respiration was consistently lower under feathermoss, intermediate under sphagnum, and higher under lichen during all three years. The Rs-adj/Re ratio increased from spring through autumn and ranged from 0.85 to 0.87 annually for the snow-free period. The Rs-adj/Re ratio was negatively correlated with the difference between air and shallow soil temperature and this correlation was more pronounced in autumn than summer and spring. Maximum photosynthetic capacity of the forest floor (Pff-max) saturated at low irradiance levels (~200 μmol m-2 s-1) and decreased with increasing air temperature and vapor pressure deficit for all three ground cover types, suggesting that Pff was more limited by desiccation than by light availability. Pff-max was lowest for sphagnum, intermediate for feathermoss, and highest for lichen for two of the three years. Pff normalized for light peaked at air temperatures of 5-8°C, suggesting that this is the optimal temperature range for Pff. The Pff-eco/Peco ratio varied from 13 to 24% over the snow-free period and reached a minimum in mid-summer when both air temperature and Peco were at their maximum. On an annual basis, Pff-eco accounted for 17

  13. An empirical assessment of forest floor carbon stock components across the United States

    Science.gov (United States)

    Christopher W. Woodall; Charles H. Perry; James A. Westfall

    2012-01-01

    Despite its prevalent reporting in regional/national greenhouse gas inventories (NGHGI), forest floor (FF) carbon (C) stocks (including litter, humus, and fine woody debris [FWD]) have not been empirically measured using a consistent approach across forests of the US. The goal of this study was to use the first national field inventory of litter and humic layer depths...

  14. Contrasting responses to drought of forest floor CO2 efflux in a loblolly pine plantation and a nearby Oak-Hickory forest

    Science.gov (United States)

    S. Palmroth; Chris A. Maier; Heather R. McCarthy; A. C. Oishi; H. S. Kim; Kurt H. Johnsen; Gabrial G. Katul; Ram Oren

    2005-01-01

    Forest floor C02 efflux (Fff) depends on vegetation type, climate, and soil physical properties. We assessed the effects of biological factors on Fff by comparing a maturing pine plantation (PP) and a nearby mature Oak-Hickory-type hardwood forest (HW). Fff was measured...

  15. Carbon and nitrogen accumulation in forest floor and surface soil under different geographic origins of Maritime pine (Pinus pinaster Aiton. plantations

    Directory of Open Access Journals (Sweden)

    E. Ozdemir

    2013-07-01

    Full Text Available Aim of study : To determine if plantations consisting of different geographic origins of the Maritime pine (Pinus pinaster Aiton. could have altered C and N stocks in the forest floor and surface soils.Area of study : Forest floor and mineral soil C and N stocks were measured in four adjacent plantations of different geographic origins of Maritime pine (Gironde, Toulon, Corsica and Spain and adjacent primary native Sessile oak (Quercus petraea L. at Burunsuz region in Belgrad Forest where is located in the Istanbul province in the Marmara geographical region between 41°09' -41°12' N latitude and 28°54' - 29°00' E longitude in Turkey.Material and Methods : Plots were compared as common garden experiments without replications. 15 surface soil (0-10 cm and 15 forest floor samples were taken from each Maritime pine origins and adjacent native Sessile oak forest. C and N contents were determined on LECO Truspec 2000 CN analyzer. The statistical significance of the results was evaluated by one-way Analysis of Variance (ANOVA.Research highlights : Forest floor carbon mass, nitrogen concentration and nitrogen mass of forest floor showed a significant difference among origins. Soil carbon mass and nitrogen mass did not significantly differ among investigated plots.Keywords: carbon sequestration; C/N ratio; decomposition; exotic; tree provenance.

  16. Changes in conifer and deciduous forest foliar and forest floor chemistry and basal area tree growth across a nitrogen (N) deposition gradient in the northeastern US

    Science.gov (United States)

    Johnny L. Boggs; Steven G. McNulty; Linda H. Pardo

    2007-01-01

    We evaluated foliar and forest floor chemistry across a gradient of N deposition in the Northeast at 11 red spruce (Picea rubens Sarg.) sites in 1987/1988 and foliar and forest floor chemistry and basal area growth at six paired spruce and deciduous sites in 1999. The six red spruce plots were a subset of the original 1987/1988 spruce sites. In 1999...

  17. C2-C10 hydrocarbon emissions from a boreal wetland and forest floor

    Directory of Open Access Journals (Sweden)

    H. Hellén

    2006-01-01

    Full Text Available Emissions of various C2-C10 hydrocarbons (VOCs and halogenated hydrocarbons (VHOCs from a boreal wetland and a Scots pine forest floor in south-western Finland were measured by the static chamber technique. Isoprene was the main non-methane hydrocarbon emitted by the wetland, but small emissions of ethene, propane, propene, 1-butene, 2-methylpropene, butane, pentane and hexane were also detected. The isoprene emission from the wetland was observed to follow the commonly-used isoprene emission algorithm. The mean emission potential of isoprene was 224 µg m-2 h-1 for the whole season. This is lower than the emission potentials published earlier; that is probably at least partly due to the cold and cloudy weather during the measurements. No emissions were detected of monoterpenes or halogenated hydrocarbons from the wetland. The highest hydrocarbon emissions from the Scots pine forest floor were measured in spring and autumn. However, only a few measurements were conducted during summer. The main compounds emitted were monoterpenes. Isoprene emissions were negligible. The total monoterpene emission rates varied from zero to 373 µg m-2 h-1. The results indicated that decaying plant litter may be the source for these emissions. Small emissions of chloroform (100-800 ng m-2 h-1, ethene, propane, propene, 2-methylpropene, cis-2-butene, pentane, hexane and heptane were detected. Comparison with Scots pine emissions showed that the forest floor may be an important monoterpene source, especially in spring.

  18. Chemical characteristics and acidity of soluble organic substances from a northern hardwood forest floor, central Maine, USA

    International Nuclear Information System (INIS)

    Vance, G.F.; David, M.B.

    1991-01-01

    The authors understanding of the chemistry, structure, and reactions of organic substances in forest floor leachates is limited and incomplete. Therefore, the authors examined the organic and inorganic chemistry of forest floor leachates collected from a hardwood forest in central Maine over a two-year period (1987-1989), including detailed study of dissolved organic carbon (DOC). Seasonal variations in NH 4 + , NO 3 - , K + , and total Al were believed due to organic matter decomposition and release. Leaching of other base cations closely followed that of NO 3 - . Total DOC ranged from 2,228 to 7,193 μmol L -1 with an average of 4,835 μmol L -1 . Monosaccharides and polyphenols constituted 3.9% (range of 3.4 to 4.4%) and 3.0% (2.2 to 3.7%) of the DOC, respectively, which suggests DOC may contain partially oxidized products that are possibly of a lignocellulose nature. Fractionation of the forest floor DOC indicated high organic acid contents (hydrophobic and hydrophilic acids) that averaged 92% of the total DOC. Organic acids were isolated and analyzed for elemental content (C, H, N, and S), and determination of UV absorptivity (E 4 /E 6 ) ratios, CuO oxidation products, FT-IR and 13 C-NMR spectra, and acidity by potentiometric titration. Their FT-IR and 13 C-NMR spectra suggest they are primarily carboxylic acids, with aliphatic and aromatic structure. An organic charge contribution model was developed using titration data, DOC fractionation percentages, and the total DOC in the forest floor leachates. Application of the model to all solutions accounted for 97% of the charge balance deficits

  19. Habitat change and restoration: responses of a forest-floor mammal species to manipulations of fallen timber in floodplain forests

    Directory of Open Access Journals (Sweden)

    Mac Nally, R

    2002-05-01

    Full Text Available In forests and woodlands, fallen timber (logs and large branches is an important habitat element for many species of animals. Fallen timber has been systematically stripped in many forests, eliminating an important structural element. This study describes results of a ‘meso-scale’ experiment in which fallen timber was manipulated in a floodplain forest of the Murray River in south-eastern Australia. A thousand tons of wood were redistributed after one-year’s pre-manipulation monitoring, while a further two-year’s post-manipulation monitoring was conducted. The response of the main forest-floor small-mammal species, the Yellow-footed Antechinus Antechinus flavipes, to alterations of fallen-wood loads is documented. Results of the experiment will help to frame guidelines for fallen-timber management in these extensive floodplain forests.

  20. Forest floor and mineral soil respiration rates in a northern Minnesota red pine chronosequence

    Science.gov (United States)

    Powers, Matthew; Kolka, Randall; Bradford, John B.; Palik, Brian J.; Jurgensen, Martin

    2018-01-01

    We measured total soil CO2 efflux (RS) and efflux from the forest floor layers (RFF) in red pine (Pinus resinosaAit.) stands of different ages to examine relationships between stand age and belowground C cycling. Soil temperature and RS were often lower in a 31-year-old stand (Y31) than in 9-year-old (Y9), 61-year-old (Y61), or 123-year-old (Y123) stands. This pattern was most apparent during warm summer months, but there were no consistent differences in RFF among different-aged stands. RFF represented an average of 4–13% of total soil respiration, and forest floor removal increased moisture content in the mineral soil. We found no evidence of an age effect on the temperature sensitivity of RS, but respiration rates in Y61 and Y123 were less sensitive to low soil moisture than RS in Y9 and Y31. Our results suggest that soil respiration’s sensitivity to soil moisture may change more over the course of stand development than its sensitivity to soil temperature in red pine, and that management activities that alter landscape-scale age distributions in red pine forests could have significant impacts on rates of soil CO2 efflux from this forest type.

  1. Nitrous oxide fluxes from forest floor, tree stems and canopies of boreal tree species during spring

    Science.gov (United States)

    Haikarainen, Iikka; Halmeenmäki, Elisa; Machacova, Katerina; Pihlatie, Mari

    2017-04-01

    Boreal forests are considered as small sources of atmospheric nitrous oxide (N2O) due to microbial N2O production in the soils. Recent evidence shows that trees may play an important role in N2O exchange of forest ecosystems by offering pathways for soil produced N2O to the atmosphere. To confirm magnitude, variability and the origin of the tree mediated N2O emissions more research is needed, especially in boreal forests which have been in a minority in such investigation. We measured forest floor, tree stem and shoot N2O exchange of three boreal tree species at the beginning of the growing season (13.4.-13.6.2015) at SMEAR II station in Hyytiälä, located in Southern Finland (61˚ 51´N, 24˚ 17´E, 181 a.s.l.). The fluxes were measured in silver birch (Betula pendula), downy birch (B. pubescens) and Norway spruce (Picea abies) on two sites with differing soil type and characteristics (paludified and mineral soil), vegetation cover and forest structure. The aim was to study the vertical profile of N2O fluxes at stem level and to observe temporal changes in N2O fluxes over the beginning of the growing season. The N2O exchange was determined using the static chamber technique and gas chromatographic analyses. Scaffold towers were used for measurements at multiple stem heights and at the canopy level. Overall, the N2O fluxes from the forest floor and trees at both sites were very small and close to the detection limit. The measured trees mainly emitted N2O from their stems and shoots, while the forest floor acted as a sink of N2O at the paludified site and as a small source of N2O at the mineral soil site. Stem emissions from all the trees at both sites were on average below 0.5 μg N2O m-2 of stem area h-1, and the shoot emissions varied between 0.2 and 0.5 ng N2O m-2 g-1 dry biomass. When the N2O fluxes were scaled up to the whole forest ecosystem, based on the tree biomass and stand density, the N2O emissions from birch and spruce trees at the paludified site

  2. Changes in diversity, biomass and abundance of soil macrofauna, Parrotio-Carpinetum forest at organic and semi-organic horizons

    Directory of Open Access Journals (Sweden)

    Masomeh Izadi

    2016-07-01

    Full Text Available Present study evaluates diversity, abundance and biomass of soil macrofauna in organic and semi-organic horizons in Parrotia persica-Carpinus betulus forest in Shast kola area. Totally 70 sample points were randomly selected from organic and semi-organic horizons then sampling was done by a rectangle 100 cm2 area. Soil macrofauna were separated from soil samples by hand sorting and using Berlese funnel then dried at 60°C for 72h and weighted in 0.001 gr. With using taxonomic classification key, thirteen macrofauna orders were identified. Most of abundance of soil macrofauna in both soil horizons were allocated to Millipedes order. Changes in diversity, abundance and biomass of macrofauna in both soil horizons were calculated. The results showed Shannon diversity index, Simpson evenness and Margalef richness indices in semi-organic horizon were more than organic horizon. Abundance and biomass of macrofauna in semi-organic horizon were more than organic horizon.

  3. Input and output budgets of radiocesium concerning the forest floor in the mountain forest of Fukushima released from the TEPCO's Fukushima Dai-ichi nuclear power plant accident

    International Nuclear Information System (INIS)

    Niizato, Tadafumi; Abe, Hironobu; Mitachi, Katsuaki; Sasaki, Yoshito; Ishii, Yasuo; Watanabe, Takayoshi

    2016-01-01

    Estimations of radiocesium input and output concerning the forest floor within a mountain forest region have been conducted in the north and central part of the Abukuma Mountains of Fukushima, northeast Japan, after a 2–3 year period following the TEPCO Fukushima Dai-ichi nuclear power plant accident. The radiocesium input and output associated with surface washoff, throughfall, stemflow, and litterfall processes at experimental plots installed on the forest floor of evergreen Japanese cedars and deciduous Konara oaks have been monitored. Despite the high output potential in the mountainous forest of Fukushima, the results at both monitoring locations show the radiocesium input to be 4–50 times higher than the output during the summer monsoon in Fukushima. These results indicate that the radiocesium tends to be preserved in the forest ecosystem due to extremely low output ratios (0.05%–0.19%). Thus, the associated fluxes throughout the circulation process are key issues for the projecting the environmental fate of the radiocesium levels, along with the subsequent reconstruction of life emphasized within the setting. - Highlights: • Input and output budgets of radiocesium in the mountainous forest of Fukushima were investigated in 2013 and 2014. • "1"3"7Cs outputs were 4–50 times higher than the "1"3"7Cs outputs during the monsoons. • The proportion of "1"3"7Cs output to radiocesium inventories was in the range of 0.05%–0.19% during the monsoons. • Radiocesium tends to be preserved in the forest ecosystem due to extremely low output ratios. • The forest floor seems to be a sink of radiocesium contamination than a source for the other ecosystems.

  4. Singular and combined effects of blowdown, salvage logging, and wildfire on forest floor and soil mercury pools

    Science.gov (United States)

    Carl P.J. Mitchell; Randall K. Kolka; Shawn. Fraver

    2012-01-01

    A number of factors influence the amount of mercury (Hg) in forest floors and soils, including deposition, volatile emission, leaching, and disturbances such as fire. Currently the impact on soil Hg pools from other widespread forest disturbances such as blowdown and management practices like salvage logging are unknown. Moreover, ecological and biogeochemical...

  5. Forest floor carbon exchange of a boreal black spruce forest in eastern North America

    Directory of Open Access Journals (Sweden)

    O. Bergeron

    2009-09-01

    Full Text Available This study reports continuous automated measurements of forest floor carbon (C exchange over feathermoss, lichen, and sphagnum micro-sites in a black spruce forest in eastern North America during snow-free periods over three years. The response of soil respiration (Rs-auto and forest floor photosynthesis (Pff to environmental factors was determined. The seasonal contributions of scaled up Rs-auto adjusted for spatial representativeness (Rs-adj and Pff (Pff-eco relative to that of total ecosystem respiration (Re and photosynthesis (Peco, respectively, were also quantified.

    Shallow (5 cm soil temperature explained 67–86% of the variation in Rs-auto for all ground cover types, while deeper (50 and 100 cm soil temperatures were related to Rs-auto only for the feathermoss micro-sites. Base respiration was consistently lower under feathermoss, intermediate under sphagnum, and higher under lichen during all three years. The Rs-adj/Re ratio increased from spring through autumn and ranged from 0.85 to 0.87 annually for the snow-free period. The Rs-adj/Re ratio was negatively correlated with the difference between air and shallow soil temperature and this correlation was more pronounced in autumn than summer and spring.

    Maximum photosynthetic capacity of the forest floor (Pff-max saturated at low irradiance levels (~200 μmol m−2 s−1 and decreased with increasing air temperature and vapor pressure deficit for all three ground cover types, suggesting that Pff was more limited by desiccation than by light availability. Pff-max was lowest for sphagnum, intermediate for feathermoss, and highest for lichen for two

  6. Investigation of radioactive cesium transportation from forest canopy to floor by litterfall, stemflow and throughfall in northern Fukushima

    Science.gov (United States)

    Endo, I.; Ohte, N.; Iseda, K.; Tanoi, K.; Hirose, A.; Kobayashi, N. I.; Murakami, M.; Tokuchi, N.; Ohashi, M.

    2015-12-01

    After the Fukushima Daiichi nuclear power plant accident due to Great East Japan Earthquake in March 11th 2011, large areas of forest have been highly contaminated by the radioactive nuclides. Most of the deposited radioactive material to the canopy is then washed out with rainfall or leaf fall due to the tree phenology. There have been studies showing that the amount of 137Cs transportation differs among litter components and water pathways, and was affected by seasonal variations. Thus, to evaluate the amount of 137Cs flux from canopy to forest floor, continuous monitoring of each component (litterfall, throughfall and stemflow) is required. We investigated the annual transfer of 137Cs from the forest canopy to the floor by litterfall, throughfall and stemflow at two different forest types in northern Fukushima after two years from the accident. Seasonal variations in 137Cs transportation and differences between forests types were also determined. Forest sites were set in the upstream part of Kami-Oguni River catchment at Date city, which locates approximately 50km northwest from the Fukushima Dai-ichi Nuclear Power Plant. The study sites consisted of two deciduous (Mixed deciduous-1, Mixed deciduous-2) and one cedar (Cedar plantation) stands. The cumulative 137Cs transportation from the forest canopy to the floor was 6.6 kBq m-2 year-1 for the Mixed deciduous-1, 3.9 kBq m-2 year-1 for the Mixed deciduous-2 and 11.0 kBq m-2 year-1 for the Cedar plantation. 137Cs transportation with litterfall increased in the defoliation period which correlated with the increased amount of litterfall. 137Cs transportation with throughfall and stemflow increased in the rainy season. 137Cs flux by litterfall was higher in Cedar plantation compared with that of mixed deciduous forests, while the opposite result was obtained for stemflow. The ratio of annual 137Cs flux and the estimated 137Cs amount deposited in the forests will be discussed.

  7. Changes in conifer and deciduous forest foliar and forest floor chemistry and basal area tree growth across a nitrogen (N) deposition gradient in the northeastern US

    International Nuclear Information System (INIS)

    Boggs, Johnny L.; McNulty, Steven G.; Pardo, Linda H.

    2007-01-01

    We evaluated foliar and forest floor chemistry across a gradient of N deposition in the Northeast at 11 red spruce (Picea rubens Sarg.) sites in 1987/1988 and foliar and forest floor chemistry and basal area growth at six paired spruce and deciduous sites in 1999. The six red spruce plots were a subset of the original 1987/1988 spruce sites. In 1999, we observed a significant correlation between mean growing season temperature and red spruce basal area growth. Red spruce and deciduous foliar %N correlated significantly with N deposition. Although N deposition has not changed significantly from 1987/1988 to 1999, net nitrification potential decreased significantly at Whiteface. This decrease in net potential nitrification is not consistent with the N saturation hypothesis and suggests that non-N deposition controls, such as climatic factors and immobilization of down dead wood, might have limited N cycling. - Data from the 1999 remeasurement of the red spruce forests suggest that N deposition, to some extent, is continuing to influence red spruce across the northeastern US as illustrated by a significant correlation between N deposition and red spruce foliar %N. Our data also suggest that the decrease in forest floor %N and net nitrification potential across sites from 1987 to 1999 may be due to factors other than N deposition, such as climatic factors and N immobilization in fine woody material (<5 cm diameter)

  8. Effect of tree species on carbon stocks in forest floor and mineral soil and implications for soil carbon inventories

    NARCIS (Netherlands)

    Schulp, C.J.E.; Nabuurs, G.J.; Verburg, P.H.; Waal, de R.W.

    2008-01-01

    Forest soil organic carbon (SOC) and forest floor carbon (FFC) stocks are highly variable. The sampling effort required to assess SOC and FFC stocks is therefore large, resulting in limited sampling and poor estimates of the size, spatial distribution, and changes in SOC and FFC stocks in many

  9. Chemistry of burning the forest floor during the FROSTFIRE experimental burn, interior Alaska, 1999.

    Science.gov (United States)

    J.W. Harden; J.C. Neff; D.V. Sandberg; M.R. Turetsky; R. Ottmar; G. Gleixner; T.L. Fries; K.L. Manies

    2004-01-01

    Wildfires represent one of the most common disturbances in boreal regions, and have the potential to reduce C, N, and Hg stocks in soils while contributing to atmospheric emissions. Organic soil layers of the forest floor were sampled before and after the FROSTFIRE experimental burn in interior Alaska, and were analyzed for bulk density, major and trace elements, and...

  10. Microbial transformations of C and N in a boreal forest floor as affected by temperature

    NARCIS (Netherlands)

    Verburg, P.S.J.; Dam, van D.; Hefting, M.M.; Tietema, A.

    1999-01-01

    The effects of temperature on N mineralization were studied in two organic surface horizons (LF and H) of soil from a boreal forest. The soil was incubated at 5 °C and 15 °C after adding 15 N and gross N fluxes were calculated using a numerical simulation model. The model was calibrated on microbial

  11. Carbon content of forest floor and mineral soil in Mediterranean Pinus spp. and Oak stands in acid soils in Northern Spain

    Energy Technology Data Exchange (ETDEWEB)

    Herrero, C.; Turrión, M.B.; Pando, V.; Bravo, F.

    2016-07-01

    Aim of the study: The aim of the study was to determine the baseline carbon stock in forest floor and mineral soils in pine and oak stands in acid soils in Northern Spain. Area of study: The study area is situated in northern Spain (42° N, 4° W) on “Paramos y Valles” region of Palencia. aterial and methods: An extensive monitoring composed of 48 plots (31 in pine and 17 in oak stands) was carried out. Litter layers and mineral soil samples, at depths of 0-30 cm and 30-60 cm, were taken in each plot. An intensive monitoring was also performed by sampling 12 of these 48 plots selected taken in account species forest composition and their stand development stage. Microbial biomass C (CMB), C mineralization (CRB), and soil organic C balance at stand level were determined in surface soil samples of intensive monitoring. Main results: No differences in soil C content were detected in the two forest ecosystems up to 60 cm depth (53.0±25.8 Mg C ha-1 in Pinus spp. plantations and 60.3±43.8 Mg C ha-1 in oak stands). However, differences in total C (CT), CMB and CRB were found in the upper 10 cm of the soils depending on the stand development stage in each species forest composition (Pinus nigra, Pinus pinaster, Pinus sylvestris and Quercus pyrenaica). Plots with high development stage exhibited significant lower metabolic quotient (qCO2), so, meant more efficient utilization of C by the microbial community. The C content in the forest floor was higher in pine stands (13.7±0.9 Mg C ha-1) than in oak stands (5.4±0.7 Mg C ha-1). A greater turnover time was found in pine ecosystems vs. oak stands. In contrast, forest floor H layer was nonexistent in oak stands. Research highlights: Results about litterfall, forest floor and mineral soil dynamics in this paper can be used strategically to reach environmental goals in new afforestation programs and sustainable forest management approaches. (Author)

  12. Topographic heterogeneity effect on the accumulation of Fukushima-derived radiocesium on forest floor driven by biologically mediated processes

    Science.gov (United States)

    Koarashi, Jun; Atarashi-Andoh, Mariko; Takeuchi, Erina; Nishimura, Syusaku

    2014-10-01

    The accident at the Fukushima Daiichi nuclear power plant caused serious radiocesium (137Cs) contamination of forest ecosystems located in mountainous and hilly regions with steep terrain. To understand topographic effects on the redistribution and accumulation of 137Cs on forest floor, we investigated the distribution of Fukushima-derived 137Cs in forest-floor litter layers on a steep hillslope in a Japanese deciduous forest in August 2013 (29 months after the accident). Both leaf-litter materials and litter-associated 137Cs were accumulated in large amounts at the bottom of the hillslope. At the bottom, a significant fraction (65%) of the 137Cs inventory was observed to be associated with newly shed and less degraded leaf-litter materials, with estimated mean ages of 0.5-1.5 years, added via litterfall after the accident. Newly emerged leaves were contaminated with Fukushima-derived 137Cs in May 2011 (two months after the accident) and 137Cs concentration in them decreased with time. However, the concentrations were still two orders of magnitude higher than the pre-accident level in 2013 and 2014. These observations are the first to show that 137Cs redistribution on a forested hillslope is strongly controlled by biologically mediated processes and continues to supply 137Cs to the bottom via litterfall at a reduced rate.

  13. Elevated Atmospheric CO2 and Warming Stimulates Growth and Nitrogen Fixation in a Common Forest Floor Cyanobacterium under Axenic Conditions

    Directory of Open Access Journals (Sweden)

    Zoë Lindo

    2017-03-01

    Full Text Available The predominant input of available nitrogen (N in boreal forest ecosystems originates from moss-associated cyanobacteria, which fix unavailable atmospheric N2, contribute to the soil N pool, and thereby support forest productivity. Alongside climate warming, increases in atmospheric CO2 concentrations are expected in Canada’s boreal region over the next century, yet little is known about the combined effects of these factors on N fixation by forest floor cyanobacteria. Here we assess changes in N fixation in a common forest floor, moss-associated cyanobacterium, Nostoc punctiforme Hariot, under elevated CO2 conditions over 30 days and warming combined with elevated CO2 over 90 days. We measured rates of growth and changes in the number of specialized N2 fixing heterocyst cells, as well as the overall N fixing activity of the cultures. Elevated CO2 stimulated growth and N fixation overall, but this result was influenced by the growth stage of the cyanobacteria, which in turn was influenced by our temperature treatments. Taken together, climate change factors of warming and elevated CO2 are expected to stimulate N2 fixation by moss-associated cyanobacteria in boreal forest systems.

  14. Longleaf pine site response to repeated fertilization and forest floor removal by raking and prescribed burning

    Science.gov (United States)

    Kim Ludovici; Robert Eaton; Stanley Zarnoch

    2018-01-01

    Removal of forest floor litter by pine needle raking and prescribed burning is a common practice in longleaf pine (Pinus palustris Mill.) stands on Coastal Plain sites in the Southeastern United States. Repeated removal of litter by raking and the loss of surface organic matter from controlled burns can affect the...

  15. Organic horizon and mineral soil mercury along three clear-cut forest chronosequences across the northeastern USA.

    Science.gov (United States)

    Richardson, Justin B; Petrenko, Chelsea L; Friedland, Andrew J

    2017-12-01

    Mercury (Hg) is a globally distributed pollutant trace metal that has been increasing in terrestrial environments due to rising anthropogenic emissions. Vegetation plays an important role in Hg sequestration in forested environments, but increasing tree removal for biofuels and wood products may affect this process. The long-term effect of clear-cutting on forest soil Hg remains uncertain, since most studies are limited to measuring changes for event. The chronosequence approach, which substitutes space for time using forest stands of different ages since clear-cutting, allows for investigation of processes occurring over decades to centuries. Here, we utilized three clear-cut forest soil chronosequences across the northeastern USA to understand Hg accumulation and retention over several decades. Total Hg concentrations and pools were quantified for five soil depth increments along three chronosequences. Our results showed Hg concentrations and pools decreased in the initial 20 years following clear-cutting. Mineral soil Hg pools decreased 21-53% (7-14 mg m -2 ) between 1-5-year-old stands and 15-25-year-old stands but mineral soil Hg pools recovered in 55-140-year-old stands to similar values as measured in 1-5-year-old stands. Our study is one of the first to demonstrate a decrease and recovery in Hg pool size. These changes in Hg did not correspond with changes in bulk density, soil C, or pH. We utilized a simple two-box model to determine how different Hg fluxes affected organic and mineral soil horizon Hg pools. Our simple model suggests that changes in litterfall and volatilization rates could have caused the observed changes in organic horizon Hg pools. However, only increases in leaching could reproduce observed decreases to mineral soil Hg pools. Further studies are needed to determine the mechanism of Hg loss from forest soils following clear-cutting.

  16. Regional Variability of Cd, Hg, Pb and C Concentrations in Different Horizons of Swedish Forest Soils

    International Nuclear Information System (INIS)

    Alriksson, A.

    2001-01-01

    Contents of cadmium (Cd), mercury (Hg), lead (Pb) and carbon(C) in the O, B and C horizons of podzolized forest soils in Sweden were surveyed. Concentrations and storage of Cd, Hg and Pb in the O and B horizons were high in southern Sweden and gradually decreased towards the north, though with considerable local variability. This pattern reflects the influence of anthropogenic emissions of these metals, as well as the effects of soil-forming processes. Parent till material, as represented by the C horizon concentration of the respective metal, accounted for little of the variation in metal concentration in the O horizon. For Cd and Pb, the correlations were not significant or slightly negative (R 2 = 0.12 and 0.09 respectively) depending on region, while for Hg the correlation was not significant or slightly positive (R 2 = 0.03 and 0.08). Furthermore, parent till material accounted for more of the variation in metal concentrations in the B horizons in the northern part of Sweden than in the middle and southernmost parts, where the concentration of total carbon had more influence. The correlation between the metal concentrations in the B and C horizon was strongest for Pb (R 2 = 0.63 and 0.36 in the two northernmost regions), lower for Cd (R 2 = 0.19 and 0.16) and not significant for Hg. For all soil horizons, total C concentration accounted for much of the variation in Hg concentration in particular (O-horizon R 2 = 0.15-0.69, B horizon R 2 = 0.36-0.50, C horizon R 2 = 0.23-0.50 and ns in one region). Ratios of metal concentrations between the B and C horizons were highest for Hg(maximum value of 30), indicating a relatively larger addition or retention of Hg compared to Cd and Pb (maximum value of 10)in the B horizon. This study indicate that factors other than parent material account for the large scale variation in O horizon concentrations of metals but patterns correspond well with those of atmospheric deposition of heavy metals and acidifying substances

  17. Effects of wood ash fertilization on forest floor greenhouse gas emissions and tree growth in nutrient poor drained peatland forests

    International Nuclear Information System (INIS)

    Ernfors, M.; Sikstroem, U.; Nilsson, M.; Klemedtsson, L.

    2010-01-01

    Wood ash (3.1, 3.3 or 6.6 tonnes dry weight ha -1 ) was used to fertilize two drained and forested peatland sites in southern Sweden. The sites were chosen to represent the Swedish peatlands that are most suitable for ash fertilization, with respect to stand growth response. The fluxes of carbon dioxide (CO 2 ), methane (CH 4 ) and nitrous oxide (N 2 O) from the forest floor, measured using opaque static chambers, were monitored at both sites during 2004 and 2005 and at one of the sites during the period 1 October 2007-1 October 2008. No significant (p > 0.05) changes in forest floor greenhouse gas exchange were detected. The annual emissions of CO 2 from the sites varied between 6.4 and 15.4 tonnes ha -1 , while the CH 4 fluxes varied between 1.9 and 12.5 kg ha -1 . The emissions of N 2 O were negligible. Ash fertilization increased soil pH at a depth of 0-0.05 m by up to 0.9 units (p 2 ha -1 year -1 and 0.52 m 2 ha -1 year -1 , respectively). The stand biomass, which was calculated using tree biomass functions, was not significantly affected by the ash treatment. The groundwater levels during the 2008 growing season were lower in the high ash dose plots than in the corresponding control plots (p < 0.05), indicating increased evapotranspiration as a result of increased tree growth. The larger basal area increment and the lowered groundwater levels in the high ash dose plots suggest that fertilization promoted tree growth, while not affecting greenhouse gas emissions.

  18. Respiration rates in forest soil organic horizon materials treated with simulated acid rain

    Energy Technology Data Exchange (ETDEWEB)

    Salonius, P O

    1990-01-01

    The entire organic horizon above the mineral soil was collected under a mature black spruce (Picea mariana) stand in central New Brunswick. The organic horizon consisted of litter, fermentation, and humus layers of 1.5, 4.0, and 1.0 cm depths respectively. In concert with a series of simulated rain experiments, which dealt with the effects of acid precipitation of pH 4.6, 3.6, and 2.6 compared with controls at pH 5.6 on germination and early growth of forest tree seedlings, 30 randomly distributed, unplanted tubes in each rain chamber were exposed to treatment during each of the 5-week treatments of the various tree species. During the experiments, ca 315 mm of simulated rain was deposited on the soil surfaces in the tube containers. Marked decreases in soil microbial activity were found only with pH 2.6 rain, but responsiveness to increasing temperature was lower as rain of greater acidity was applied to the soil. Ammonium nitrogen mineralization rates were not affected by treatment of soil with acidified precipitation. 26 refs., 3 figs., 1 tab.

  19. Comparative analysis of the influence of climate change and nitrogen deposition on carbon sequestration in forest ecosystems in European Russia: simulation modelling approach

    Directory of Open Access Journals (Sweden)

    A. S. Komarov

    2012-11-01

    Full Text Available An individual-based simulation model, EFIMOD, was used to simulate the response of forest ecosystems to climate change and additional nitrogen deposition. The general scheme of the model includes forest growth depending on nitrogen uptake by plants and mineralization of soil organic matter. The mineralization rate is dependent on nitrogen content in litter and forest floor horizons. Three large forest areas in European Central Russia with a total area of about 17 000 km2 in distinct environmental conditions were chosen. Simulations were carried out with two climatic scenarios (ambient climate and climate change and different levels of nitrogen deposition (ambient value and increase by 6 and 12 kg N ha−1 yr−1. The simulations showed that increased nitrogen deposition leads to increased productivity of trees, increased organic matter content in organic soil horizons, and an increased portion of deciduous tree species. For the climate change scenario, the same effects on forest productivity and similar shifts in species composition were predicted but the accumulation of organic matter in soil was decreased.

  20. Trace Metals and Metalloids in Forest Soils and Exotic Earthworms in Northern New England, USA

    Science.gov (United States)

    Richardson, J.B.; Görres, J.H.; Jackson, B.P.; Friedland, A.J.

    2015-01-01

    Trace metals and metalloids (TMM) in forest soils and invasive earthworms were studied at 9 uncontaminated sites in northern New England, USA. Essential (Cu, Mo, Ni, Zn, Se) and toxic (As, Cd, Pb, Hg and U) TMM concentrations (mg kg-1) and pools (mg m-2) were quantified for organic horizons (forest floor), mineral soils and earthworm tissues. Essential TMM tissue concentrations were greatest for mineral soil-feeding earthworm Octolasion cyaneum. Toxic TMM tissue concentrations were highest for organic horizon-feeding earthworms Dendobaena octaedra, Aporrectodea rosea and Amynthas agrestis. Most earthworm species had attained tissue concentrations of Pb, Hg and Se potentially hazardous to predators. Bioaccumulation factors were Cd > Se > Hg > Zn > Pb > U > 1.0 > Cu > As > Mo > Ni. Only Cd, Se Hg and Zn were considered strongly bioaccumulated by earthworms because their average bioaccumulation factors were significantly greater than 1.0. Differences in bioaccumulation did not appear to be caused by soil concentrations as earthworm TMM tissue concentrations were poorly correlated with TMM soil concentrations. Instead, TMM bioaccumulation appears to be species and site dependent. The invasive Amynthas agrestis had the greatest tissue TMM pools, due to its large body mass and high abundance at our stands. We observed that TMM tissue pools in earthworms were comparable or exceeded organic horizon TMM pools; earthworm tissue pools of Cd were up 12 times greater than in the organic horizon. Thus, exotic earthworms may represent an unaccounted portion and flux of TMM in forests of the northeastern US. Our results highlight the importance of earthworms in TMM cycling in northern forests and warrant more research into their impact across the region. PMID:25883392

  1. Preferential Flow Paths Allow Deposition of Mobile Organic Carbon Deep into Soil B Horizons

    Science.gov (United States)

    Marin-Spiotta, E.; Chadwick, O.; Kramer, M. G.

    2009-12-01

    reinforce preferential flow paths. SOM in the deepest mineral horizons has C:N ratios similar to that of the forest floor which is dominated by recent litter inputs, suggesting an accumulation of plant-derived material that has undergone little microbial processing. SOM accumulating at depth differs chemically from decomposing roots as determined by 13C-NMR spectrometry, and shows strong contributions of organic acids, pointing to a likely DOM source. NMR spectra and radiocarbon concentrations of SOM at depth also match material in the surface humic mineral horizons (Bh), where the network of cracks and channels are first observable. Microbial biomass is significantly lower in the deepest mineral horizons but the differences with soil depth disappear when corrected for total soil C. Radiocarbon concentrations of bulk soils and of respired CO2 from incubated mineral horizons at 50 cm show that SOM at depth is a mixture of modern and old C, providing further evidence for the downward movement of significant amounts of fresh C from the surface horizons.

  2. Uncertainties in detecting decadal change in extractable soil elements in Northern Forests

    Science.gov (United States)

    Bartlett, O.; Bailey, S. W.; Ducey, M. J.

    2016-12-01

    Northern Forest ecosystems have been or are being impacted by land use change, forest harvesting, acid deposition, atmospheric CO2 enrichment, and climate change. Each of these has the potential to modify soil forming processes, and the resulting chemical stocks. Horizontal and vertical variations in concentrations complicate determination of temporal change. This study evaluates sample design, sample size, and differences among observers as sources of uncertainty when quantifying soil temporal change over regional scales. Forty permanent, northern hardwood, monitoring plots were established on the White Mountain National Forest in central New Hampshire and western Maine. Soil pits were characterized and sampled by genetic horizon at plot center in 2001 and resampled again in 2014 two-meters on contour from the original sampling location. Each soil horizon was characterized by depth, color, texture, structure, consistency, boundaries, coarse fragments, and roots from the forest floor to the upper C horizon, the relatively unaltered glacial till parent material. Laboratory analyses included pH in 0.01 M CaCl2 solution and extractable Ca, Mg, Na, K, Al, Mn, and P in 1 M NH4OAc solution buffered at pH 4.8. Significant elemental differences were identified by genetic horizon from paired t-tests (p ≤ 0.05) indicate temporal change across the study region. Power analysis, 0.9 power (α = 0.05), revealed sampling size was appropriate within this region to detect concentration change by genetic horizon using a stratified sample design based on topographic metrics. There were no significant differences between observers' descriptions of physical properties. As physical properties would not be expected to change over a decade, this suggests spatial variation in physical properties between the pairs of sampling pits did not detract from our ability to detect temporal change. These results suggest that resampling efforts within a site, repeated across a region, to quantify

  3. The impact of four decades of annual nitrogen addition on dissolved organic matter in a boreal forest soil

    Science.gov (United States)

    Rappe-George, M. O.; Gärdenäs, A. I.; Kleja, D. B.

    2013-03-01

    Addition of mineral nitrogen (N) can alter the concentration and quality of dissolved organic matter (DOM) in forest soils. The aim of this study was to assess the effect of long-term mineral N addition on soil solution concentration of dissolved organic carbon (DOC) and dissolved organic nitrogen (DON) in Stråsan experimental forest (Norway spruce) in central Sweden. N was added yearly at two levels of intensity and duration: the N1 treatment represented a lower intensity but a longer duration (43 yr) of N addition than the shorter N2 treatment (24 yr). N additions were terminated in the N2 treatment in 1991. The N treatments began in 1967 when the spruce stands were 9 yr old. Soil solution in the forest floor O, and soil mineral B, horizons were sampled during the growing seasons of 1995 and 2009. Tension and non-tension lysimeters were installed in the O horizon (n = 6), and tension lysimeters were installed in the underlying B horizon (n = 4): soil solution was sampled at two-week intervals. Although tree growth and O horizon carbon (C) and N stock increased in treatments N1 and N2, the concentration of DOC in O horizon leachates was similar in both N treatments and control. This suggests an inhibitory direct effect of N addition on O horizon DOC. Elevated DON and nitrate in O horizon leachates in the ongoing N1 treatment indicated a move towards N saturation. In B horizon leachates, the N1 treatment approximately doubled leachate concentrations of DOC and DON. DON returned to control levels, but DOC remained elevated in B horizon leachates in N2 plots nineteen years after termination of N addition. We propose three possible explanations for the increased DOC in mineral soil: (i) the result of decomposition of a larger amount of root litter, either directly producing DOC or (ii) indirectly via priming of old SOM, and/or (iii) a suppression of extracellular oxidative enzymes.

  4. The impact of four decades of annual nitrogen addition on dissolved organic matter in a boreal forest soil

    Directory of Open Access Journals (Sweden)

    M. O. Rappe-George

    2013-03-01

    Full Text Available Addition of mineral nitrogen (N can alter the concentration and quality of dissolved organic matter (DOM in forest soils. The aim of this study was to assess the effect of long-term mineral N addition on soil solution concentration of dissolved organic carbon (DOC and dissolved organic nitrogen (DON in Stråsan experimental forest (Norway spruce in central Sweden. N was added yearly at two levels of intensity and duration: the N1 treatment represented a lower intensity but a longer duration (43 yr of N addition than the shorter N2 treatment (24 yr. N additions were terminated in the N2 treatment in 1991. The N treatments began in 1967 when the spruce stands were 9 yr old. Soil solution in the forest floor O, and soil mineral B, horizons were sampled during the growing seasons of 1995 and 2009. Tension and non-tension lysimeters were installed in the O horizon (n = 6, and tension lysimeters were installed in the underlying B horizon (n = 4: soil solution was sampled at two-week intervals. Although tree growth and O horizon carbon (C and N stock increased in treatments N1 and N2, the concentration of DOC in O horizon leachates was similar in both N treatments and control. This suggests an inhibitory direct effect of N addition on O horizon DOC. Elevated DON and nitrate in O horizon leachates in the ongoing N1 treatment indicated a move towards N saturation. In B horizon leachates, the N1 treatment approximately doubled leachate concentrations of DOC and DON. DON returned to control levels, but DOC remained elevated in B horizon leachates in N2 plots nineteen years after termination of N addition. We propose three possible explanations for the increased DOC in mineral soil: (i the result of decomposition of a larger amount of root litter, either directly producing DOC or (ii indirectly via priming of old SOM, and/or (iii a suppression of extracellular oxidative enzymes.

  5. Effect of tree species and soil properties on nutrient immobilization in the forest floor

    DEFF Research Database (Denmark)

    Raulund-Rasmussen, Karsten; Vejre, Henrik

    1995-01-01

    of ammonium, nitrate and phosphate in the soil solution was much higher at the loamy site under all species showing a stronger microbial activity. It is therefore hypothesized that the differences in accumulation rates were, at least partly, caused by differences in the mineralization regimes. Strong root...... infiltration in the forest floors at the sandy site compared to almost none at the loamy site, is probably responsible for the differences in mineralization rate due to competition between the organic matter decomposers and the tree-roots/mycorrhiza for nutrients. Author Keywords: EFFECTS OF ROOTS; NUTRIENT...

  6. Isolated Horizon, Killing Horizon and Event Horizon

    OpenAIRE

    Date, G.

    2001-01-01

    We consider space-times which in addition to admitting an isolated horizon also admit Killing horizons with or without an event horizon. We show that an isolated horizon is a Killing horizon provided either (1) it admits a stationary neighbourhood or (2) it admits a neighbourhood with two independent, commuting Killing vectors. A Killing horizon is always an isolated horizon. For the case when an event horizon is definable, all conceivable relative locations of isolated horizon and event hori...

  7. Accumulation of policyclic aromatic hydrocarbons (PAHs) in surface litter and soils in four forests in the United States

    Science.gov (United States)

    Obrist, D.; Perlinger, J. A.; Zielinska, B.

    2014-12-01

    Polycyclic aromatic hydrocarbons (PAHs) are toxic environmental pollutants originating from the incomplete combustion of organic material, both from natural or anthropogenic sources. Once emitted, they can be transported across thousands of kilometers impacting remote environments. Here, we characterize the distribution of 23 PAHs and 9 oxygenated PAHs (Σ32PAH) in litter and soils in four remote forests in the United States. Concentrations of Σ32PAH in fresh surface litter (Oi layers) showed very low levels in three of the four forests (mixed coniferous forest in Maine, deciduous blue oak forest in California, and a coniferous forest in Washington State), with PAHs levels much lower than those reported in previous studies from Europe. The analysis showed that PAHs represented a mix of regional background sources. Highest PAH levels were observed in a coniferous forest floor in Florida, attributable to frequent prescribed burning of understory vegetation at this site, and supported by high contributions of retene (>7%; compared to atmospheric deposition. Within mineral soils, Σ32PAH:OC ratios increased with depth (Ah horizons: 750±198 ng g-1; B horizons: 1,202±97 ng g-1), indicating that vertical transfer in mineral soils leads to significant accumulation of PAH in subsoils. ΣPAH:OC increases observed in deeper soil layers may be attributed to slower mineralization rates of PAHs compared to OC, plus vertical transport as indicated by preferential enrichment of PAHs with low Kow (i.e., more water-soluble PAHs). Finally, percentage of potentially biologically produced PAH (Σ Naph+Phen+Pery) were low and consistent across the litter/soil horizons, suggesting that biological production is minor or absent at our sites.

  8. Effects of intensive harvesting on forest floor properties in Betula papyrifera stands in Newfoundland

    International Nuclear Information System (INIS)

    Roberts, B.A.; Deering, K.W.; Titus, B.D.

    1998-01-01

    This study investigates litter and organic matter production and related site ecology in nine medium to high quality Betula papyrifera stands in three locations in central Newfoundland on a variety of land form and drainage conditions. Three sites, Badger West (BW), Moose Pond (MP) and Middleton Lake (ML) were selected. The ML site has the highest quality (with the best height/age ratio, 18 m/60 yr, and height/DBH ratio, 18 m/30 cm), followed by MP and BW. Litter depth on well developed moders or mulls was usually 2 - 3 cm and varied from 1 - 15 cm. Forest floor depths (measured in 324 profiles) rarely reached 20 cm and was commonly 5 - 10 cm; it varied with position and site. Total and available nutrients indicate that B. papyrifera produces one of the highest-quality organic matter types of the local forest types and is important in improving site quality. The mean N-concentration in green foliage (2.21 %) and trapped litter (1.03 %) was highest at the best quality site ML, followed by MP and BW. The concentration of calcium, 0.85 %, was highest at the poorest quality site. Four years after harvesting, litter depth significantly decreased in all sites and treatments with the exception of the BW whole-tree harvest treatment. Total forest floor depth significantly decreased at all sites in the stem-only harvest treatment as well as the MP whole-tree harvest treatment. There was a significant decrease in available nitrogen following harvesting in both treatments at both the MP and BW sites. Change in available phosphorus was insignificant, with the exception of an increase in the MP stem-only harvest treatment. There was a significant decrease in available potassium at both the ML and BW whole-tree harvest treatments, but a significant increase in the stem-only harvest treatments at ML and MP. There was a significant decrease in available calcium in both treatments at both the MP and BW sites 34 refs, 4 figs, 1 tab

  9. Bacterial Flux by Net Precipitation from the Phyllosphere to the Forest Floor.

    Science.gov (United States)

    Pound, P.; Van Stan, J. T., II; Moore, L. D.; Bittar, T.

    2016-12-01

    Transport pathways of microbes between ecosystem spheres (atmosphere, phyllosphere, and pedosphere) represent major fluxes in nutrient cycles and have the potential to significantly affect microbial ecological processes. We quantified a previously unexamined microbial flux from the phyllosphere to the pedosphere during rainfall and found it to be substantial. Net rainfall bacterial fluxes for throughfall and stemflow were quantified using flow cytometry and a quantitative Polymerase Chain Reaction (qPCR) assay for a Quercus virginiana (Mill., southern live oak) forest with heavy epiphyte cover of Tillandsia usneoides (L., Spanish moss) and Pleopeltis polypodiodes (L., resurrection fern) in coastal Georgia (Southeast USA). Total net precipitation flux of bacteria was 15 quadrillion cells year-1 ha-1, which (assuming a bacterial cell mass of 1 pg) is approximately 15 kg of bacterial biomass supply per year. Stemflow generation was low in this stand (rarely exceeded 10 L storm-1) yet still delivered half the annual net precipitation flux due to high bacterial concentration. The role of this previously unquantified bacterial flux in the forest floor has also been under studied, yet it may be significant by contributing functional community members (if living) or labile lysates (if dead).

  10. Empirical observations offer improved estimates of forest floor carbon content across in the United States

    Science.gov (United States)

    Perry, C. H.; Domke, G. M.; Walters, B. F.; Smith, J. E.; Woodall, C. W.

    2014-12-01

    The Forest Inventory and Analysis (FIA) program of the United States Forest Service reports official estimates of national forest floor carbon (FFC) stocks and stock change to national and international parties, the US Environmental Protection Agency (USEPA) and the United Nations Framework Convention on Climate Change (UNFCCC), respectively. These estimates of national FFC stocks are derived from plot-level predictions of FFC density. We suspect the models used to predict plot-level FFC density are less than ideal for several reasons: (a) they are based upon local studies that may not reflect FFC dynamics at the national scale, (b) they are relatively insensitive to climate change, and (c) they reduce the natural variability of the data leading to misplaced confidence in the estimates. However, FIA has measured forest floor attributes since 2001 on a systematic 1/16th subset of a nation-wide array of inventory plots (7 800 of 125 000 plots). Here we address the efficacy of replacing plot-level model predictions with empirical observations of FFC density while assessing the impact of imputing FFC density values to the full plot network on national stock estimates. First, using an equivalence testing framework, we found model predictions of FFC density to differ significantly from the observations in all regions and forest types; the mean difference across all plots was 21 percent (1.81 Mg·ha-1). Furthermore, the model predictions were biased towards the lower end of extant FFC density observations, underestimating it while greatly truncating the range relative to the observations. Second, the optimal imputation approach (k-Nearest Neighbor, k-NN) resulted in values that were equivalent to observations of FFC density across a range of simulated missingness and maintained the high variability seen in the observations. We used the k-NN approach to impute FFC density values to the 94 percent of FIA inventory plots without soil measurements. Third, using the imputed

  11. Microbial activities in forest soils exposed to chronic depositions from a lignite power plant

    Energy Technology Data Exchange (ETDEWEB)

    Klose, S.; Wernecke, K.D.; Makeschin, F. [Technical University of Dresden, Tharandt (Germany)

    2004-12-01

    Atmospheric emissions of fly ash and SO{sub 2} from lignite-fired power plants strongly affect large forest areas in Germany. The impact of different deposition loads on the microbial biomass and enzyme activities was studied at three forest sites (Picea abies (L.) Karst.) along an emission gradient of 3, 6, and 15 km downwind of a coal-fired power plant, representing high, moderate and low emission rates. An additional site at a distance of 3 km from the power plant was chosen to study the influence of forest type on microbial parameters in coniferous forest soils under fly ash and SO{sub 2} emissions. Soil microbial biomass C and N, CO{sub 2} evolved and activities of L-asparaginase, L-glutaminase, beta-glucosidase, acid phosphatase and arylsulfatase (expressed on dry soil and organic C basis) were determined in the forest floor (L, Of and Oh horizon) and mineral top soil (0-10 cm). It is concluded that chronic fly ash depositions decrease litter decomposition by influencing specific microbial and enzymatic processes in forest soils.

  12. Severe soil frost reduced losses of carbon and nitrogen from the forest floor during simulated snowmelt: A laboratory experiment

    Science.gov (United States)

    Andrew B. Reinmann; Pamela H. Templer; John L. Campbell

    2012-01-01

    Considerable progress has been made in understanding the impacts of soil frost on carbon (C) and nitrogen (N) cycling, but the effects of soil frost on C and N fluxes during snowmelt remain poorly understood. We conducted a laboratory experiment to determine the effects of soil frost on C and N fluxes from forest floor soils during snowmelt. Soil cores were collected...

  13. Parameterized isoprene and monoterpene emissions from the boreal forest floor: Implementation into a 1D chemistry-transport model and investigation of the influence on atmospheric chemistry

    Science.gov (United States)

    Mogensen, Ditte; Aaltonen, Hermanni; Aalto, Juho; Bäck, Jaana; Kieloaho, Antti-Jussi; Gierens, Rosa; Smolander, Sampo; Kulmala, Markku; Boy, Michael

    2015-04-01

    Volatile organic compounds (VOCs) are emitted from the biosphere and can work as precursor gases for aerosol particles that can affect the climate (e.g. Makkonen et al., ACP, 2012). VOC emissions from needles and leaves have gained the most attention, however other parts of the ecosystem also have the ability to emit a vast amount of VOCs. This, often neglected, source can be important e.g. at periods where leaves are absent. Both sources and drivers related to forest floor emission of VOCs are currently limited. It is thought that the sources are mainly due to degradation of organic matter (Isidorov and Jdanova, Chemosphere, 2002), living roots (Asensio et al., Soil Biol. Biochem., 2008) and ground vegetation. The drivers are biotic (e.g. microbes) and abiotic (e.g. temperature and moisture). However, the relative importance of the sources and the drivers individually are currently poorly understood. Further, the relative importance of these factors is highly dependent on the tree species occupying the area of interest. The emission of isoprene and monoterpenes where measured from the boreal forest floor at the SMEAR II station in Southern Finland (Hari and Kulmala, Boreal Env. Res., 2005) during the snow-free period in 2010-2012. We used a dynamic method with 3 automated chambers analyzed by Proton Transfer Reaction - Mass Spectrometer (Aaltonen et al., Plant Soil, 2013). Using this data, we have developed empirical parameterizations for the emission of isoprene and monoterpenes from the forest floor. These parameterizations depends on abiotic factors, however, since the parameterizations are based on field measurements, biotic features are captured. Further, we have used the 1D chemistry-transport model SOSAA (Boy et al., ACP, 2011) to test the seasonal relative importance of inclusion of these parameterizations of the forest floor compared to the canopy crown emissions, on the atmospheric reactivity throughout the canopy.

  14. Incubation of air-pollution-control residues from secondary Pb smelter in deciduous and coniferous organic soil horizons: Leachability of lead, cadmium and zinc

    Energy Technology Data Exchange (ETDEWEB)

    Chrastny, Vladislav, E-mail: vladislavchrastny@seznam.cz [University of South Bohemia, Faculty of Science, Studentska 13, 370 05 Ceske Budejovice (Czech Republic); Czech University of Life Sciences Prague, Faculty of Environmental Sciences, Kamycka 129, 165 21 Prague 6 (Czech Republic); Vanek, Ales [Czech University of Life Sciences Prague, Faculty of Agrobiology, Food and Natural Resources, Kamycka 129, 165 21 Praha 6 (Czech Republic); Komarek, Michael [Czech University of Life Sciences Prague, Faculty of Environmental Sciences, Kamycka 129, 165 21 Prague 6 (Czech Republic); Farkas, Juraj [Czech Geological Survey, Geologicka 6, 152 00 Praha 5 (Czech Republic); Drabek, Ondrej; Vokurkova, Petra [Czech University of Life Sciences Prague, Faculty of Agrobiology, Food and Natural Resources, Kamycka 129, 165 21 Praha 6 (Czech Republic); Nemcova, Jana [University of South Bohemia, Faculty of Agriculture, Studentska 13, 370 05 Ceske Budejovice (Czech Republic)

    2012-03-30

    Highlights: Black-Right-Pointing-Pointer Pb smelter fly ash was incubated in forest soil horizons to assess metal mobility. Black-Right-Pointing-Pointer The metal mobilization depends on pH and the ratio of humic/fulvic acids to SOM. Black-Right-Pointing-Pointer The lowest mobilization of Pb, Zn and Cd took place in horizon H (coniferous forest). Black-Right-Pointing-Pointer A huge amount of Cd was found to have leached in the horizon F (deciduous forest). Black-Right-Pointing-Pointer More vulnerable to metal leaching from APC residues is soil from deciduous forest. - Abstract: The leachability of air-pollution-control (APC) residues from a secondary lead smelter in organic soil horizons (F and H) from a deciduous and a coniferous forest during incubation periods of 0, 3 and 6 months were compared in this work. While the concentration of Pb, Zn and Cd associated with the exchangeable/acid extractable fraction in the horizon F from the coniferous forest was higher compared to the deciduous, significantly lower concentrations in the humified horizon H was found. It is suggested that lower pH and a higher share of fulvic acids fraction (FAs) of solid phase soil organic matter (SOM) in the humified soil horizon H from the coniferous compared to the deciduous forest is responsible for a higher metal association with solid phase SOM and therefore a lower metal leaching in a soil system. From this point of view, the humified soil horizon H from the deciduous forest represents a soil system more vulnerable to Pb, Zn and Cd leaching from APC residues.

  15. Redistribution of soil nitrogen, carbon and organic matter by mechanical disturbance during whole-tree harvesting in northern hardwoods

    Science.gov (United States)

    Ryan, D.F.; Huntington, T.G.; Wayne, Martin C.

    1992-01-01

    To investigate whether mechanical mixing during harvesting could account for losses observed from forest floor, we measured surface disturbance on a 22 ha watershed that was whole-tree harvested. Surface soil on each 10 cm interval along 81, randomly placed transects was classified immediately after harvesting as mineral or organic, and as undisturbed, depressed, rutted, mounded, scarified, or scalped (forest floor scraped away). We quantitatively sampled these surface categories to collect soil in which preharvest forest floor might reside after harvest. Mechanically mixed mineral and organic soil horizons were readily identified. Buried forest floor under mixed mineral soil occurred in 57% of mounds with mineral surface soil. Harvesting disturbed 65% of the watershed surface and removed forest floor from 25% of the area. Mechanically mixed soil under ruts with organic or mineral surface soil, and mounds with mineral surface soil contained organic carbon and nitrogen pools significantly greater than undisturbed forest floor. Mechanical mixing into underlying mineral soil could account for the loss of forest floor observed between the preharvest condition and the second growing season after whole-tree harvesting. ?? 1992.

  16. Modification of Soil Solid Aluminium Phases During an Extreme Experimental Acidification of A Horizons of Forest Soils from Southwest Europe

    International Nuclear Information System (INIS)

    Novoa-Munoz, J. C.; Garcia-Rodeja Gayoso, E.

    2007-01-01

    Four umbric A horizons from acid forest soils were acidified in a batch type experiment and its effect in the Al pools of the solid phase analysed by means of selective dissolution methods. The results showed that Al release accounted for the consumption of 85-99% of the added protons, and causes a decrease of 2-33% of the 'reactive' Al pool of the soil solid phase. In these A horizons, inorganic non-crystalline Al and high stability Al-humus complexes are the main sources of the dissolved Al. The contribution of the complexes with intermediate stability only was relevant in the more acid horizon developed from phyllites (P18-A). The increase of equilibration time from 96 to 720 h did not caused significant differences in the decrease of the 'reactive' Al pool suggesting the acid neutralising reactions occurred in less than 96 h. In most cases the quantity of released Al is in agreement with the decrease of the different reactive Al pools of the solid phase

  17. Forest soils

    Science.gov (United States)

    Charles H. (Hobie) Perry; Michael C. Amacher

    2009-01-01

    Productive soils are the foundation of sustainable forests throughout the United States. Forest soils are generally subjected to fewer disturbances than agricultural soils, particularly those that are tilled, so forest soils tend to have better preserved A-horizons than agricultural soils. Another major contrast between forest and agricultural soils is the addition of...

  18. Competition and habitat selection in a forest-floor small mammal fauna

    Energy Technology Data Exchange (ETDEWEB)

    Dueser, R D [Univ. of Virginia, Charlottesville; Hallett, J G

    1980-01-01

    In a study of habitat exploitation in a forest-floor small mammal community, we have collected habitat and population data for Peromyscus leucopus, Ochrotomys nuttalli, and Tamias striatus. Using multiple regression analysis, researchers estimate the effects of habitat selection and competition on the local distributions of these species during three seasons. Each of the partial regression coefficients relating the density of an independent species to the density of the dependent species is negative. This result indicates that competition is pervasive among these species. Competitive ability and habitat selectivity both increase in the order Peromyscus-Tamias-Ochrotomys. Peromyscus is a poorly competitive habitat generalist, Ochrotomys is a strongly competitive habitat specialist, and Tamias is intermediate in both respects. The competitive hierarchy is stable between seasons. These results both confirm the conclusions reached in previous studies of this small mammal community and suggest the design of experiments to further clarify the mode and consequences of interaction between these species.

  19. HORIZON SENSING

    Energy Technology Data Exchange (ETDEWEB)

    Larry G. Stolarczyk

    2003-03-18

    With the aid of a DOE grant (No. DE-FC26-01NT41050), Stolar Research Corporation (Stolar) developed the Horizon Sensor (HS) to distinguish between the different layers of a coal seam. Mounted on mining machine cutter drums, HS units can detect or sense the horizon between the coal seam and the roof and floor rock, providing the opportunity to accurately mine the section of the seam most desired. HS also enables accurate cutting of minimum height if that is the operator's objective. Often when cutting is done out-of-seam, the head-positioning function facilitates a fixed mining height to minimize dilution. With this technology, miners can still be at a remote location, yet cut only the clean coal, resulting in a much more efficient overall process. The objectives of this project were to demonstrate the feasibility of horizon sensing on mining machines and demonstrate that Horizon Sensing can allow coal to be cut cleaner and more efficiently. Stolar's primary goal was to develop the Horizon Sensor (HS) into an enabling technology for full or partial automation or ''agile mining''. This technical innovation (R&D 100 Award Winner) is quickly demonstrating improvements in productivity and miner safety at several prominent coal mines in the United States. In addition, the HS system can enable the cutting of cleaner coal. Stolar has driven the HS program on the philosophy that cutting cleaner coal means burning cleaner coal. The sensor, located inches from the cutting bits, is based upon the physics principles of a Resonant Microstrip Patch Antenna (RMPA). When it is in proximity of the rock-coal interface, the RMPA impedance varies depending on the thickness of uncut coal. The impedance is measured by the computer-controlled electronics and then sent by radio waves to the mining machine. The worker at the machine can read the data via a Graphical User Interface, displaying a color-coded image of the coal being cut, and direct the machine

  20. Long-term litter input manipulation effects on production and properties of dissolved organic matter in the forest floor of a Norway spruce stand.

    NARCIS (Netherlands)

    Klotzbücher, T.; Kaiser, K.; Stepper, C.; van Loon, E.; Gerstberger, P.; Kalbitz, K.

    2012-01-01

    Background and aims Environmental factors such as climate and atmospheric CO2 control inputs of plant-derived matter into soils, which then determines properties and decomposition of soil organic matter. We studied how dissolved organic matter (DOM) in forest floors responded to six years of litter

  1. Lead sequestration and species redistribution during soil organic matter decomposition

    Science.gov (United States)

    Schroth, A.W.; Bostick, B.C.; Kaste, J.M.; Friedland, A.J.

    2008-01-01

    The turnover of soil organic matter (SOM) maintains a dynamic chemical environment in the forest floor that can impact metal speciation on relatively short timescales. Here we measure the speciation of Pb in controlled and natural organic (O) soil horizons to quantify changes in metal partitioning during SOM decomposition in different forest litters. We provide a link between the sequestration of pollutant Pb in O-horizons, estimated by forest floor Pb inventories, and speciation using synchrotron-based X-ray fluorescence and X-ray absorption spectroscopy. When Pb was introduced to fresh forest Oi samples, it adsorbed primarily to SOM surfaces, but as decomposition progressed over two years in controlled experiments, up to 60% of the Pb was redistributed to pedogenic birnessite and ferrihydrite surfaces. In addition, a significant fraction of pollutant Pb in natural soil profiles was associated with similar mineral phases (???20-35%) and SOM (???65-80%). Conifer forests have at least 2-fold higher Pb burdens in the forest floor relative to deciduous forests due to more efficient atmospheric scavenging and slower organic matter turnover. We demonstrate that pedogenic minerals play an important role in surface soil Pb sequestration, particularly in deciduous forests, and should be considered in any assessment of pollutant Pb mobility. ?? 2008 American Chemical Society.

  2. Factors influencing organic-horizon carbon pools in mixed-species stands of central Maine, USA

    Science.gov (United States)

    Joshua J. Puhlick; Shawn Fraver; Ivan J. Fernandez; Aaron R. Weiskittel; Laura S. Kenefic; Randy Kolka; Marie-Cecile Gruselle

    2016-01-01

    The overall goal of this study was to evaluate the correlation of multiple abiotic and biotic factors with organic-horizon (O-horizon) carbon (C) content on the Penobscot Experimental Forest in central Maine, USA. O-horizon samples were collected and their associated depths were recorded from stands managed with a range of silvicultural and harvesting treatments (i.e...

  3. Knowledge horizons: the present and the promise of knowledge management

    National Research Council Canada - National Science Library

    Chauvel, Daniele; Despres, Charles

    2000-01-01

    ... what has been written, Butterworth- Heinemann prints its books on acid-free paper whenever possible. Butterworth- Heinemann supports the efforts of American Forests and the Global ReLeaf program in its campaign for the betterment of trees, forests, and our environment. Library of Congress Cataloging-in-Publication Data Knowledge horizons : the present ...

  4. Linking foliar chemistry to forest floor solid and solution phase organic C and N in Picea ahies [L.) Karst stands in northern Bohemia

    Czech Academy of Sciences Publication Activity Database

    Aitkenhead-Peterson, J. A.; Alexander, J.E.; Albrechtová, J.; Krám, P.; Rock, B.; Cudlín, Pavel; Hruška, J.; Lhotáková, Z.; Huntley, R.; Oulehle, F.; Polák, T.; McDowel, W.H.

    2006-01-01

    Roč. 283, 1-2 (2006), s. 187-201 ISSN 0032-079X R&D Projects: GA MŠk ME 658 Institutional research plan: CEZ:AV0Z60870520 Keywords : cellulose and nitrogen * dissolved organic carbon * dissolved organic nitrogen * forest floor C:N * foliar Iignin, * Picea abies [L.] Karst Subject RIV: GK - Forestry Impact factor: 1.495, year: 2006

  5. Effects of sulphur pollution on forest floor invertebrates (community structure, structural heterogeneity, edge effects, decomposition, Callioplus euoplus, Pterostichus adstrictus, Scaphinotus marginatus)

    Energy Technology Data Exchange (ETDEWEB)

    Carcamo, H. A.

    1997-12-31

    The distribution of insects and other invertebrates was studied in forests under varying regimes of exposure to sulfur compounds in the vicinity of two sour gas plants and at sharp acidification gradients in pine and aspen forests located near a sulfur block. Results showed no effect on most invertebrates at moderate levels of sulfur deposition. At this level, structural heterogeneity of the forest floor was more influential than sulfur levels in determining the macroarthropoid community structure. By contrast, high sulphur contamination and subsequent acidification had a clear negative effect on earthworms, and various species of spiders. Ground beetles and certain epigeic spiders along the sharp acidification gradient at the pine forest were considered vulnerable but resistant and favoured. These results suggested that ecological specialists were most vulnerable to acidification effects, while ecological generalists have been more successful in resisting the effects of acidification. It was also shown that indirect effects at the landscape, habitat or forest type, and microhabitat level, were more important in the case of most of the arthropods than the direct effects. Only earthworms, snails and some Collembola were negatively affected through direct acidity effects.

  6. Effects of sulphur pollution on forest floor invertebrates (community structure, structural heterogeneity, edge effects, decomposition, Callioplus euoplus, Pterostichus adstrictus, Scaphinotus marginatus)

    International Nuclear Information System (INIS)

    Carcamo, H. A.

    1997-01-01

    The distribution of insects and other invertebrates was studied in forests under varying regimes of exposure to sulfur compounds in the vicinity of two sour gas plants and at sharp acidification gradients in pine and aspen forests located near a sulfur block. Results showed no effect on most invertebrates at moderate levels of sulfur deposition. At this level, structural heterogeneity of the forest floor was more influential than sulfur levels in determining the macroarthropoid community structure. By contrast, high sulphur contamination and subsequent acidification had a clear negative effect on earthworms, and various species of spiders. Ground beetles and certain epigeic spiders along the sharp acidification gradient at the pine forest were considered vulnerable but resistant and favoured. These results suggested that ecological specialists were most vulnerable to acidification effects, while ecological generalists have been more successful in resisting the effects of acidification. It was also shown that indirect effects at the landscape, habitat or forest type, and microhabitat level, were more important in the case of most of the arthropods than the direct effects. Only earthworms, snails and some Collembola were negatively affected through direct acidity effects

  7. Incubation of air-pollution-control residues from secondary Pb smelter in deciduous and coniferous organic soil horizons: leachability of lead, cadmium and zinc.

    Science.gov (United States)

    Chrastný, Vladislav; Vaněk, Aleš; Komárek, Michael; Farkaš, Juraj; Drábek, Ondřej; Vokurková, Petra; Němcová, Jana

    2012-03-30

    The leachability of air-pollution-control (APC) residues from a secondary lead smelter in organic soil horizons (F and H) from a deciduous and a coniferous forest during incubation periods of 0, 3 and 6 months were compared in this work. While the concentration of Pb, Zn and Cd associated with the exchangeable/acid extractable fraction in the horizon F from the coniferous forest was higher compared to the deciduous, significantly lower concentrations in the humified horizon H was found. It is suggested that lower pH and a higher share of fulvic acids fraction (FAs) of solid phase soil organic matter (SOM) in the humified soil horizon H from the coniferous compared to the deciduous forest is responsible for a higher metal association with solid phase SOM and therefore a lower metal leaching in a soil system. From this point of view, the humified soil horizon H from the deciduous forest represents a soil system more vulnerable to Pb, Zn and Cd leaching from APC residues. Copyright © 2012 Elsevier B.V. All rights reserved.

  8. Mineral cycling in a young Douglas fir forest stand

    International Nuclear Information System (INIS)

    Riekerk, H.

    1978-01-01

    Radiotracers for phosphorus ( 32 P), potassium (substitute 86 Rb), and calcium ( 45 Ca) were used to follow the turnover of nutrients entering the forest floor with rainwash. Phosphorus moved readily through the forest floor to be strongly retained by the acid mineral soil. Considerable phosphorus absorbed by trees was correlated with forest-floor leachate contents and became concentrated in physiologically active tissues. Losses with litterfall and rainwash were nondetectable; this indicated high retention and internal redistribution. Rapid movement toward sinks appeared to be characteristic. In contrast, the larger amounts of calcium added were absorbed by the exchange capacity of the forest floor, with subsequent small but relatively unrestricted movement through the soil and trees. Both calcium and potassium absorption by trees was correlated with mineral-soil leachate contents. Annual potassium mobility fell between that of phosphorus and calcium and appeared to be more dependent on temperature and moisture conditions of the forest ecosystem, with potassium moving rapidly in subcycles during wet periods of the growing season

  9. Forest structure and downed woody debris in boreal, temperate, and tropical forest fragments.

    Science.gov (United States)

    Gould, William A; González, Grizelle; Hudak, Andrew T; Hollingsworth, Teresa Nettleton; Hollingsworth, Jamie

    2008-12-01

    Forest fragmentation affects the heterogeneity of accumulated fuels by increasing the diversity of forest types and by increasing forest edges. This heterogeneity has implications in how we manage fuels, fire, and forests. Understanding the relative importance of fragmentation on woody biomass within a single climatic regime, and along climatic gradients, will improve our ability to manage forest fuels and predict fire behavior. In this study we assessed forest fuel characteristics in stands of differing moisture, i.e., dry and moist forests, structure, i.e., open canopy (typically younger) vs. closed canopy (typically older) stands, and size, i.e., small (10-14 ha), medium (33 to 60 ha), and large (100-240 ha) along a climatic gradient of boreal, temperate, and tropical forests. We measured duff, litter, fine and coarse woody debris, standing dead, and live biomass in a series of plots along a transect from outside the forest edge to the fragment interior. The goal was to determine how forest structure and fuel characteristics varied along this transect and whether this variation differed with temperature, moisture, structure, and fragment size. We found nonlinear relationships of coarse woody debris, fine woody debris, standing dead and live tree biomass with mean annual median temperature. Biomass for these variables was greatest in temperate sites. Forest floor fuels (duff and litter) had a linear relationship with temperature and biomass was greatest in boreal sites. In a five-way multivariate analysis of variance we found that temperature, moisture, and age/structure had significant effects on forest floor fuels, downed woody debris, and live tree biomass. Fragment size had an effect on forest floor fuels and live tree biomass. Distance from forest edge had significant effects for only a few subgroups sampled. With some exceptions edges were not distinguishable from interiors in terms of fuels.

  10. Effects of tree leaf litter, deer fecal pellets, and soil properties on growth of an introduced earthworm (Lumbricus terrestris): Implications for invasion dynamics

    Science.gov (United States)

    Kassidy N. Yatso; Erik A. Lilleskov

    2016-01-01

    Invasive earthworm communities are expanding into previously earthworm-free forests of North America, producing profound ecosystem changes. Lumbricus terrestris is an invasive anecic earthworm that consumes a large portion of the detritus on the soil surface, eliminating forest floor organic horizons and reducing soil organic matter. Two mesocosm...

  11. Phosphatase activity in relation to key litter and soil properties in mature subtropical forests in China.

    Science.gov (United States)

    Hou, Enqing; Chen, Chengrong; Wen, Dazhi; Liu, Xian

    2015-05-15

    Phosphatase-mediated phosphorus (P) mineralization is one of the critical processes in biogeochemical cycling of P and determines soil P availability in forest ecosystems; however, the regulation of soil phosphatase activity remains elusive. This study investigated the potential extracellular activities of acid phosphomonoesterase (AcPME) and phosphodiesterase (PDE) and how they were related to key edaphic properties in the L horizon (undecomposed litter) and F/H horizon (fermented and humified litter) and the underlying mineral soil at the 0-15cm depth in eight mature subtropical forests in China. AcPME activity decreased significantly in the order of F/H horizon>L horizon>mineral soil horizon, while the order for PDE activity was L horizon=F/H horizon>mineral soil horizon. AcPME (X axis) and PDE (Y axis) activities were positively correlated in all horizons with significantly higher slope in the L and F/H horizons than in the mineral soil horizon. Both AcPME and PDE activities were positively related to microbial biomass C, moisture content and water-holding capacity in the L horizon, and were positively related to soil C:P, N:P and C:N ratios and fine root (diameter≤2mm) biomass in the mineral soil horizon. Both enzyme activities were also interactively affected by forest and horizon, partly due to the interactive effect of forest and horizon on microbial biomass. Our results suggest that modulator(s) of the potential extracellular activity of phosphatases vary with horizon, depending on the relative C, P and water availability of the horizon. Copyright © 2015 Elsevier B.V. All rights reserved.

  12. Distinctive fungal and bacterial communities are associated with mats formed by ectomycorrhizal fungi

    Science.gov (United States)

    Laurel A. Kluber; Jane E. Smith; David D. Myrold

    2011-01-01

    The distinct rhizomorphic mats formed by ectomycorrhizal Piloderma fungi are common features of the organic soil horizons of coniferous forests of the Pacific Northwest. These mats have been found to cover 25-40% of the forest floor in some Douglas-fir stands, and are associated with physical and biochemical properties that distinguish them from...

  13. Comparison of Organic Matter Dynamics in Soil between Japanese Cedar (Cryptomeria japonica) Forest and Adjacent Japanese Red Pine (Pinus densiflora) Forest Established on Flatland

    OpenAIRE

    Terumasa, Takahashi; Akiko, Minami; Yoshito, Asano; Tatsuaki, Kobayashi; Faculty of Horticulture, Chiba Universit; Faculty of Horticulture, Chiba University:(Present)Hashikami town office; Faculty of Horticulture, Chiba University; Faculty of Horticulture, Chiba University

    1999-01-01

    In order to clarify the effects of tree species on organic matter dynamics in soil, we investigated the amount of forest floor material, leaf litter decomposition rate, soil chemical characteristics, soil respiration rate and cellulose decomposition rate in a Japanese cedar forest (cedar plot) and an adjacent Japanese red pine forest (pine plot) established on a flatland. The amount of forest floor material in the cedar plot was 34.5 Mg ha^ which was greater than that in the pine plot. Becaus...

  14. A deep organic horizon, evidence of inter-stadium Wurm II-III in forest of Fontainebleau

    International Nuclear Information System (INIS)

    Robin, A.M.; Barthelemy, L.

    1996-01-01

    A black horizon with 33 % organic matter and certainly of pedologic origin, at 4 m depth and cryo-perturbed or displaced, was found to be 29-30,000 years old by 14 C dating. The pollen spectrum indicated vegetation representative of his period. The 4 m of overlying sediment are a repetition of different layers, submitted to pedogenic processes. Clayey-sandy horizons were sometimes markedly cryo-perturbed and/or displaced or truncated. The pollen diagram as a whole showed a cycle of sterile horizons and horizons bearing the same vegetation. (authors). 9 refs., 2 figs., 1 tab

  15. Short-Term Belowground Responses to Thinning and Burning Treatments in Southwestern Ponderosa Pine Forests of the USA

    Directory of Open Access Journals (Sweden)

    Steven T. Overby

    2016-02-01

    Full Text Available Microbial-mediated decomposition and nutrient mineralization are major drivers of forest productivity. As landscape-scale fuel reduction treatments are being implemented throughout the fire-prone western United States of America, it is important to evaluate operationally how these wildfire mitigation treatments alter belowground processes. We quantified these important belowground components before and after management-applied fuel treatments of thinning alone, thinning combined with prescribed fire, and prescribed fire in ponderosa pine (Pinus ponderosa stands at the Southwest Plateau, Fire and Fire Surrogate site, Arizona. Fuel treatments did not alter pH, total carbon and nitrogen (N concentrations, or base cations of the forest floor (O horizon or mineral soil (0–5 cm during this 2-year study. In situ rates of net N mineralization and nitrification in the surface mineral soil (0–15 cm increased 6 months after thinning with prescribed fire treatments; thinning only resulted in net N immobilization. The rates returned to pre-treatment levels after one year. Based on phospholipid fatty acid composition, microbial communities in treated areas were similar to untreated areas (control in the surface organic horizon and mineral soil (0–5 cm after treatments. Soil potential enzyme activities were not significantly altered by any of the three fuel treatments. Our results suggest that a variety of one-time alternative fuel treatments can reduce fire hazard without degrading soil fertility.

  16. Nitrogen retention in contrasting temperate forests exposed to high nitrogen deposition

    Science.gov (United States)

    Staelens, J.; Adriaenssens, S.; Wuyts, K.; Verheyen, K.; Boeckx, P. F.

    2011-12-01

    was studied by spraying three pulses of 15N onto the forest floor during the growing season, either as ammonium or as nitrate. Four months and one year after the first application, 15N recovery was determined in the organic and mineral soil layers, fine tree roots, soil water percolate, ferns, and tree foliage. As hypothesized, N retention in the forest floor and mineral soil horizons was lower in the pine stand compared to oak, while N retention was lower for nitrate than for ammonium in both stands. The differences in 15N retention confirm that tree species affect the N balance of ecosystems under high anthropogenic N inputs and agree with the findings on gross soil N dynamics and N input-output budgets. Overall, the research underlines the importance of considering the interaction between tree species and carbon and N turnover when assessing the response of forest ecosystems to global change scenarios.

  17. A disconnect between O horizon and mineral soil carbon - Implications for soil C sequestration

    Science.gov (United States)

    Garten, Charles T., Jr.

    2009-03-01

    Changing inputs of carbon to soil is one means of potentially increasing carbon sequestration in soils for the purpose of mitigating projected increases in atmospheric CO 2 concentrations. The effect of manipulations of aboveground carbon input on soil carbon storage was tested in a temperate, deciduous forest in east Tennessee, USA. A 4.5-year experiment included exclusion of aboveground litterfall and supplemental litter additions (three times ambient) in an upland and a valley that differed in soil nitrogen availability. The estimated decomposition rate of the carbon stock in the O horizon was greater in the valley than in the upland due to higher litter quality (i.e., lower C/N ratios). Short-term litter exclusion or addition had no effect on carbon stock in the mineral soil, measured to a depth of 30 cm, or the partitioning of carbon in the mineral soil between particulate- and mineral-associated organic matter. A two-compartment model was used to interpret results from the field experiments. Field data and a sensitivity analysis of the model were consistent with little carbon transfer between the O horizon and the mineral soil. Increasing aboveground carbon input does not appear to be an effective means of promoting carbon sequestration in forest soil at the location of the present study because a disconnect exists in carbon dynamics between O horizon and mineral soil. Factors that directly increase inputs to belowground soil carbon, via roots, or reduce decomposition rates of organic matter are more likely to benefit efforts to increase carbon sequestration in forests where carbon dynamics in the O horizon are uncoupled from the mineral soil.

  18. Sphagnum mosses limit total carbon consumption during fire in Alaskan black spruce forests

    Science.gov (United States)

    G. Shetler; .R. Turetsky; E. Kane; E. Kasischke

    2008-01-01

    The high water retention of hummock-forming Sphagnum species minimizes soil moisture fluctuations and might protect forest floor organic matter from burning during wildfire. We hypothesized that Sphagnum cover reduces overall forest floor organic matter consumption during wildfire compared with other ground-layer vegetation. We...

  19. Floor interaction

    DEFF Research Database (Denmark)

    Petersen, Marianne Graves; Krogh, Peter; Ludvigsen, Martin

    2005-01-01

    Within architecture, there is a long tradition of careful design of floors. The design has been concerned with both decorating floors and designing floors to carry information. Ubiquitous computing technology offers new opportunities for designing interactive floors. This paper presents three...... different interactive floor concepts. Through an urban perspective it draws upon the experiences of floors in architecture, and provides a set of design issues for designing interactive floors....

  20. Environmental parameters regulating sulfur retention in a variety of forest soils

    International Nuclear Information System (INIS)

    Watwood, M.E.

    1987-01-01

    Field incubations utilizing 35 S-labelled sulfate were conducted in a white pine and a hardwood forest. The A horizon soil formed approximately 3.0 nmol of organic S g -1 dry weight, which did not differ significantly from results obtained in similarly designed laboratory incubations. Total intrinsic S in this horizon contained substantial amounts of sulfonate S and ester sulfate, and organic 35 S fractions in several linkage groups were found to predominate following field incubation. Capacities for sulfate adsorption, organic S formation and organic S mineralization were assayed for 01/02, A1, E2 and Bh horizons of a coastal pine forest. A1 horizon soil from various locations within New Mexico National Forests adsorbed 1.2 to 4.9 nmol g -1 of added sulfate and formed between 1.6 and 4.8 nmol g -1 of added sulfate and formed between 1.6 and 4.8 nmol g -1 of organic S during 48h. Methionine mineralization and the fate of both mineralization-derived and added sulfate were examined in hardwood forest soils which had been suction dried to contain between 2 and 80% moisture. Incubation of 35 S-methionine with organic matter extracted from the 02 litter layer of a hardwood forest, resulted in the formation of 35 S-methionine-labelled organic component

  1. A study of the carbon dynamics of Japanese grassland and forest using 14C and 13C

    International Nuclear Information System (INIS)

    Katsuno, Kazumi; Miyairi, Yosuke; Tamura, Kenji; Matsuzaki, Hiroyuki; Fukuda, Kenji

    2010-01-01

    We quantified the carbon contents of grassland and forest soil using conventional methods and studied the changes in their dynamics by measuring δ 13 C and Δ 14 C. Soil samples were taken from a neighboring Miscanthus sinensis grassland and Pinus densiflora forest in central Japan. Both had been maintained as grassland until the 1960s, when the latter was abandoned and became a pine forest by natural succession. The soil carbon content of the forest was much lower than that of the grassland, implying that the soil carbon decreased as the grassland became forest. The δ 13 C values were very similar in the grassland and forest, at approximately -20 per mille , suggesting that M. sinensis (a C4 plant) contributed to carbon storage, whereas there was little carbon accumulation from P. densiflora (a C3 plant) in forest soil. The Δ 14 C values and calculated soil carbon mean residence time (MRT) showed that the soil carbon in the upper A horizon was older, and that in the lower A horizon was younger in forest than in grassland. From these results, we conclude that young, fast-MRT soil carbon is decomposed in the upper A horizon, and old, stable soil carbon was decomposed in the lower A horizon after the pine invasion.

  2. The spatial relation between the event horizon and trapping horizon

    International Nuclear Information System (INIS)

    Nielsen, Alex B

    2010-01-01

    The relation between event horizons and trapping horizons is investigated in a number of different situations with emphasis on their role in thermodynamics. A notion of constant change is introduced that in certain situations allows the location of the event horizon to be found locally. When the black hole is accreting matter the difference in area between the two different horizons can be many orders of magnitude larger than the Planck area. When the black hole is evaporating, the difference is small on the Planck scale. A model is introduced that shows how trapping horizons can be expected to appear outside the event horizon before the black hole starts to evaporate. Finally, a modified definition is introduced to invariantly define the location of the trapping horizon under a conformal transformation. In this case the trapping horizon is not always a marginally outer trapped surface.

  3. Perceived floor slipperiness and floor roughness in a gait experiment.

    Science.gov (United States)

    Yu, Ruifeng; Li, Kai Way

    2015-01-01

    Slips and falls contribute to occupational injuries and fatalities globally. Both floor slipperiness and floor roughness affect the occurrence of slipping and falling. Investigations on fall-related phenomena are important for the safety and health of workers. The purposes of this study were to: compare the perceived floor slipperiness before and after walking on the floor; compare the perceived floor slipperiness with and without shoes for males and females; discuss the perceived floor roughness based on barefoot walking; and establish regression models to describe the relationship between perceived floor slipperiness and actual friction of the floors. Male and female subjects walked on 3 m walkways with or without shoes. The perceived floor slipperiness ratings both before and after their walk were collected. The perceived floor slipperiness both before and after walking were significantly affected by both floor and surface conditions. Gender, floor, surface, and footwear conditions were all significant factors affecting the adjustment of perceived floor slipperiness. The subjects made more adjustment on perceived floor slipperiness rating when they had shoes on than when they were barefooted. Regression models were established to describe the relationship between perceived floor slipperiness and floor coefficient of friction. These models may be used to estimate perceived floor slipperiness, or in reverse, the coefficient of friction of the floor, so as to prevent slipping and falling in workplaces.

  4. Organic Matter Stocks and the Interactions of Humic Substances with Metals in Araucaria Moist Forest Soil with Humic and Histic Horizons

    Directory of Open Access Journals (Sweden)

    Daniel Hanke

    Full Text Available ABSTRACT Soils with humic and histic horizons in tropical and subtropical ecosystems play an important role in determining the atmospheric C stock and its stabilization, climate regulation, water holding capacity, and environmental filtering, due to the different functions of soil organic matter (SOM. However, the processes and mechanisms that regulate SOM dynamics in these soils are not clear. The objectives of this study were: i determine the C and N stocks and ii investigate the SOM chemical fractions and their interactions with Fe and Al ions in soils with humic and histic horizons of a toposequence under Araucaria moist forest in southern Brazil. The soils sampled were classified as Humic Hapludox (top - not hydromorphic, Fluvaquentic Humaquepts (lower third - hydromorphic, and Typic Haplosaprists (floodplain - hydromorphic. The C and N contents were determined in bulk soil samples and SOM chemical fractions; in these fractions, Fe and Al co-extracted contents were also determined. The chemical composition of humin and humic acid fractions was investigated by FTIR spectroscopy. The C content in the toposequence increased from the top to the lowest position. The differences observed in SOM content and SOM chemical composition were defined by the differences in soil water regime. The amount of C stored in the subsurface horizons is about 70 % of total organic C. The carbohydrate-like structures in the humin fraction were protected from solubilization through interaction with iron oxides, which may represent an important mechanism for labile organic compound preservation in these soils. The soluble humic substances showed the highest Fe and Al contents, and their compartments have different affinities for Fe and Al.

  5. Wildfire and forest disease interaction lead to greater loss of soil nutrients and carbon.

    Science.gov (United States)

    Cobb, Richard C; Meentemeyer, Ross K; Rizzo, David M

    2016-09-01

    Fire and forest disease have significant ecological impacts, but the interactions of these two disturbances are rarely studied. We measured soil C, N, Ca, P, and pH in forests of the Big Sur region of California impacted by the exotic pathogen Phytophthora ramorum, cause of sudden oak death, and the 2008 Basin wildfire complex. In Big Sur, overstory tree mortality following P. ramorum invasion has been extensive in redwood and mixed evergreen forests, where the pathogen kills true oaks and tanoak (Notholithocarpus densiflorus). Sampling was conducted across a full-factorial combination of disease/no disease and burned/unburned conditions in both forest types. Forest floor organic matter and associated nutrients were greater in unburned redwood compared to unburned mixed evergreen forests. Post-fire element pools were similar between forest types, but lower in burned-invaded compared to burned-uninvaded plots. We found evidence disease-generated fuels led to increased loss of forest floor C, N, Ca, and P. The same effects were associated with lower %C and higher PO4-P in the mineral soil. Fire-disease interactions were linear functions of pre-fire host mortality which was similar between the forest types. Our analysis suggests that these effects increased forest floor C loss by as much as 24.4 and 21.3 % in redwood and mixed evergreen forests, respectively, with similar maximum losses for the other forest floor elements. Accumulation of sudden oak death generated fuels has potential to increase fire-related loss of soil nutrients at the region-scale of this disease and similar patterns are likely in other forests, where fire and disease overlap.

  6. Near horizon structure of extremal vanishing horizon black holes

    Directory of Open Access Journals (Sweden)

    S. Sadeghian

    2015-11-01

    Full Text Available We study the near horizon structure of Extremal Vanishing Horizon (EVH black holes, extremal black holes with vanishing horizon area with a vanishing one-cycle on the horizon. We construct the most general near horizon EVH and near-EVH ansatz for the metric and other fields, like dilaton and gauge fields which may be present in the theory. We prove that (1 the near horizon EVH geometry for generic gravity theory in generic dimension has a three dimensional maximally symmetric subspace; (2 if the matter fields of the theory satisfy strong energy condition either this 3d part is AdS3, or the solution is a direct product of a locally 3d flat space and a d−3 dimensional part; (3 these results extend to the near horizon geometry of near-EVH black holes, for which the AdS3 part is replaced with BTZ geometry. We present some specific near horizon EVH geometries in 3, 4 and 5 dimensions for which there is a classification. We also briefly discuss implications of these generic results for generic (gauged supergravity theories and also for the thermodynamics of near-EVH black holes and the EVH/CFT proposal.

  7. Use of the isotope flux ratio approach to investigate the C18O16O and 13CO2 exchange near the floor of a temperate deciduous forest

    Directory of Open Access Journals (Sweden)

    P. Bartlett

    2012-07-01

    Full Text Available Stable isotopologues of CO2, such as 13CO2 and C18OO, have been used to study the CO2 exchange between land and atmosphere. The advent of new measuring techniques has allowed near-continuous measurements of stable isotopes in the air. These measurements can be used with micrometeorological techniques, providing new tools to investigate the isotope exchange in ecosystems. The objectives of this study were to evaluate the use of the isotope flux ratio method (IFR near the forest floor of a temperate deciduous forest and to study the temporal dynamics of δ18O of CO2 flux near the forest floor by comparing IFR estimates with estimates of δ18O of net soil CO2 flux provided by an analytical model. Mixing ratios of 12C16O2, 13CO2 and C16O18O were measured within and above a temperate deciduous forest, using the tunable diode laser spectroscopy technique. The half-hourly compositions of the CO2 flux near the forest floor (δ13CF and δ18OF were calculated by IFR and compared with estimates provided by a modified Keeling plot technique (mKP and by a Lagrangian dispersion analysis (WT analysis. The mKP and IFR δ18OF estimates showed good agreement (slope = 1.03 and correlation, R2 = 0.80. The δ13CF estimates from the two methods varied in a narrow range of −32.7 and −23‰; the mean (± SE mKP and IFR δ13CF values were −27.5‰ (±0.2 and −27.3‰ (±0.1, respectively, and were statistically identical (p>0.05. WT analysis and IFR δ18OF estimates showed better correlation (R2 = 0.37 when only turbulent periods (u*>0.6 m s−1 were included in the analysis. The large amount of data captured (~95 % of half-hour periods evaluated for the IFR in comparison with mKP (27 % shows that the former provides new opportunities for studying δ18OF dynamics within forest canopies. Values of δ18OF showed large temporal variation, with values ranging from −31.4‰ (DOY 208 to −11.2‰ (DOY 221. Precipitation events caused substantial variation (~8

  8. Complementary models of tree species-soil relationships in old-growth temperate forests

    Science.gov (United States)

    Cross, Alison; Perakis, Steven S.

    2011-01-01

    Ecosystem level studies identify plant soil feed backs as important controls on soil nutrient availability,particularly for nitrogen and phosphorus. Although site and species specific studies of tree species soil relationships are relatively common,comparatively fewer studies consider multiple coexisting speciesin old-growth forests across a range of sites that vary underlying soil fertility. We characterized patterns in forest floor and mineral soil nutrients associated with four common tree species across eight undisturbed old-growth forests in Oregon, USA, and used two complementary conceptual models to assess tree species soil relationships. Plant soil feedbacks that could reinforce sitelevel differences in nutrient availability were assessed using the context dependent relationships model, where by relative species based differences in each soil nutrient divergedorconvergedas nutrient status changed across sites. Tree species soil relationships that did not reflect strong feedbacks were evaluated using a site independent relationships model, where by forest floor and surface mineral soil nutrient tools differed consistently by tree species across sites,without variation in deeper mineral soils. We found that theorganically cycled elements carbon, nitrogen, and phosphorus exhibited context-dependent differences among species in both forest floor and mineral soil, and most of ten followed adivergence model,where by species differences were greatest at high-nutrient sites. These patterns are consistent with the oryemphasizing biotic control of these elements through plant soil feedback mechanisms. Site independent species differences were strongest for pool so if the weather able cations calcium, magnesium, potassium,as well as phosphorus, in mineral soils. Site independent species differences in forest floor nutrients we reattributable too nespecies that displayed significant greater forest floor mass accumulation. Our finding confirmed that site-independent and

  9. Three theorems on near horizon extremal vanishing horizon geometries

    Directory of Open Access Journals (Sweden)

    S. Sadeghian

    2016-02-01

    Full Text Available EVH black holes are Extremal black holes with Vanishing Horizon area, where vanishing of horizon area is a result of having a vanishing one-cycle on the horizon. We prove three theorems regarding near horizon geometry of EVH black hole solutions to generic Einstein gravity theories in diverse dimensions. These generic gravity theories are Einstein–Maxwell-dilaton-Λ theories, and gauged or ungauged supergravity theories with U(1 Maxwell fields. Our three theorems are: (1 The near horizon geometry of any EVH black hole has a three dimensional maximally symmetric subspace. (2 If the energy momentum tensor of the theory satisfies strong energy condition either this 3d part is an AdS3, or the solution is a direct product of a locally 3d flat space and a d−3 dimensional part. (3 These results extend to the near horizon geometry of near-EVH black holes, for which the AdS3 part is replaced with BTZ geometry.

  10. Variation of biomass and carbon pools with forest type in temperate forests of Kashmir Himalaya, India.

    Science.gov (United States)

    Dar, Javid Ahmad; Sundarapandian, Somaiah

    2015-02-01

    An accurate characterization of tree, understory, deadwood, floor litter, and soil organic carbon (SOC) pools in temperate forest ecosystems is important to estimate their contribution to global carbon (C) stocks. However, this information on temperate forests of the Himalayas is lacking and fragmented. In this study, we measured C stocks of tree (aboveground and belowground biomass), understory (shrubs and herbaceous), deadwood (standing and fallen trees and stumps), floor litter, and soil from 111 plots of 50 m × 50 m each, in seven forest types: Populus deltoides (PD), Juglans regia (JR), Cedrus deodara (CD), Pinus wallichiana (PW), mixed coniferous (MC), Abies pindrow (AP), and Betula utilis (BU) in temperate forests of Kashmir Himalaya, India. The main objective of the present study is to quantify the ecosystem C pool in these seven forest types. The results showed that the tree biomass ranged from 100.8 Mg ha(-1) in BU forest to 294.8 Mg ha(-1) for the AP forest. The understory biomass ranged from 0.16 Mg ha(-1) in PD forest to 2.36 Mg ha(-1) in PW forest. Deadwood biomass ranged from 1.5 Mg ha(-1) in PD forest to 14.9 Mg ha(-1) for the AP forest, whereas forest floor litter ranged from 2.5 Mg ha(-1) in BU and JR forests to 3.1 Mg ha(-1) in MC forest. The total ecosystem carbon stocks varied from 112.5 to 205.7 Mg C ha(-1) across all the forest types. The C stocks of tree, understory, deadwood, litter, and soil ranged from 45.4 to 135.6, 0.08 to 1.18, 0.7 to 6.8, 1.1 to 1.4, and 39.1-91.4 Mg ha(-1), respectively, which accounted for 61.3, 0.2, 1.4, 0.8, and 36.3 % of the total carbon stock. BU forest accounted 65 % from soil C and 35 % from biomass, whereas PD forest contributed only 26 % from soil C and 74 % from biomass. Of the total C stock in the 0-30-cm soil, about 55 % was stored in the upper 0-10 cm. Soil C stocks in BU forest were significantly higher than those in other forests. The variability of C pools of different ecosystem components is

  11. Upland log volumes and conifer establishment patterns in two northern, upland old-growth redwood forests, a brief synopsis

    Science.gov (United States)

    Daniel J. Porter; John O. Sawyer

    2007-01-01

    We characterized the volume, weight and top surface area of naturally fallen logs in an old-growth redwood forest, and quantified conifer recruit densities on these logs and on the surrounding forest floor. We report significantly greater conifer recruit densities on log substrates as compared to the forest floor. Log substrate availability was calculated on a per...

  12. Forest soil carbon is threatened by intensive biomass harvesting.

    Science.gov (United States)

    Achat, David L; Fortin, Mathieu; Landmann, Guy; Ringeval, Bruno; Augusto, Laurent

    2015-11-04

    Forests play a key role in the carbon cycle as they store huge quantities of organic carbon, most of which is stored in soils, with a smaller part being held in vegetation. While the carbon storage capacity of forests is influenced by forestry, the long-term impacts of forest managers' decisions on soil organic carbon (SOC) remain unclear. Using a meta-analysis approach, we showed that conventional biomass harvests preserved the SOC of forests, unlike intensive harvests where logging residues were harvested to produce fuelwood. Conventional harvests caused a decrease in carbon storage in the forest floor, but when the whole soil profile was taken into account, we found that this loss in the forest floor was compensated by an accumulation of SOC in deeper soil layers. Conversely, we found that intensive harvests led to SOC losses in all layers of forest soils. We assessed the potential impact of intensive harvests on the carbon budget, focusing on managed European forests. Estimated carbon losses from forest soils suggested that intensive biomass harvests could constitute an important source of carbon transfer from forests to the atmosphere (142-497 Tg-C), partly neutralizing the role of a carbon sink played by forest soils.

  13. Ectomycorrhizal mats alter forest soil biogeochemistry

    Science.gov (United States)

    Laurel A. Kluber; Kathryn M. Tinnesand; Bruce A. Caldwell; Susie M. Dunham; Rockie R. Yarwood; Peter J. Bottomley; David D. Myrold

    2010-01-01

    Dense hyphal mats formed by ectomycorrhizal (EcM) fungi are prominent features in Douglas-fir forest ecosystems, and have been estimated to cover up to 40% of the soil surface in some forest stands. Two morphotypes of EcM mats have been previously described: rhizomorphic mats, which have thick hyphal rhizomorphs and are found primarily in the organic horizon, and...

  14. Patterns of biomass and carbon distribution across a chronosequence of Chinese pine (Pinus tabulaeformis) forests.

    Science.gov (United States)

    Zhao, Jinlong; Kang, Fengfeng; Wang, Luoxin; Yu, Xiaowen; Zhao, Weihong; Song, Xiaoshuai; Zhang, Yanlei; Chen, Feng; Sun, Yu; He, Tengfei; Han, Hairong

    2014-01-01

    Patterns of biomass and carbon (C) storage distribution across Chinese pine (Pinus tabulaeformis) natural secondary forests are poorly documented. The objectives of this study were to examine the biomass and C pools of the major ecosystem components in a replicated age sequence of P. tabulaeformis secondary forest stands in Northern China. Within each stand, biomass of above- and belowground tree, understory (shrub and herb), and forest floor were determined from plot-level investigation and destructive sampling. Allometric equations using the diameter at breast height (DBH) were developed to quantify plant biomass. C stocks in the tree and understory biomass, forest floor, and mineral soil (0-100 cm) were estimated by analyzing the C concentration of each component. The results showed that the tree biomass of P. tabulaeformis stands was ranged from 123.8 Mg·ha-1 for the young stand to 344.8 Mg·ha-1 for the mature stand. The understory biomass ranged from 1.8 Mg·ha-1 in the middle-aged stand to 3.5 Mg·ha-1 in the young stand. Forest floor biomass increased steady with stand age, ranging from 14.9 to 23.0 Mg·ha-1. The highest mean C concentration across the chronosequence was found in tree branch while the lowest mean C concentration was found in forest floor. The observed C stock of the aboveground tree, shrub, forest floor, and mineral soil increased with increasing stand age, whereas the herb C stock showed a decreasing trend with a sigmoid pattern. The C stock of forest ecosystem in young, middle-aged, immature, and mature stands were 178.1, 236.3, 297.7, and 359.8 Mg C ha-1, respectively, greater than those under similar aged P. tabulaeformis forests in China. These results are likely to be integrated into further forest management plans and generalized in other contexts to evaluate C stocks at the regional scale.

  15. Patterns of biomass and carbon distribution across a chronosequence of Chinese pine (Pinus tabulaeformis forests.

    Directory of Open Access Journals (Sweden)

    Jinlong Zhao

    Full Text Available Patterns of biomass and carbon (C storage distribution across Chinese pine (Pinus tabulaeformis natural secondary forests are poorly documented. The objectives of this study were to examine the biomass and C pools of the major ecosystem components in a replicated age sequence of P. tabulaeformis secondary forest stands in Northern China. Within each stand, biomass of above- and belowground tree, understory (shrub and herb, and forest floor were determined from plot-level investigation and destructive sampling. Allometric equations using the diameter at breast height (DBH were developed to quantify plant biomass. C stocks in the tree and understory biomass, forest floor, and mineral soil (0-100 cm were estimated by analyzing the C concentration of each component. The results showed that the tree biomass of P. tabulaeformis stands was ranged from 123.8 Mg·ha-1 for the young stand to 344.8 Mg·ha-1 for the mature stand. The understory biomass ranged from 1.8 Mg·ha-1 in the middle-aged stand to 3.5 Mg·ha-1 in the young stand. Forest floor biomass increased steady with stand age, ranging from 14.9 to 23.0 Mg·ha-1. The highest mean C concentration across the chronosequence was found in tree branch while the lowest mean C concentration was found in forest floor. The observed C stock of the aboveground tree, shrub, forest floor, and mineral soil increased with increasing stand age, whereas the herb C stock showed a decreasing trend with a sigmoid pattern. The C stock of forest ecosystem in young, middle-aged, immature, and mature stands were 178.1, 236.3, 297.7, and 359.8 Mg C ha-1, respectively, greater than those under similar aged P. tabulaeformis forests in China. These results are likely to be integrated into further forest management plans and generalized in other contexts to evaluate C stocks at the regional scale.

  16. Soil biogeochemistry properties vary between two boreal forest ecosystems in Quebec: significant differences in soil carbon, available nutrients and iron and aluminium crystallinity

    Science.gov (United States)

    Bastianelli, Carole; Ali, Adam A.; Beguin, Julien; Bergeron, Yves; Grondin, Pierre; Hély, Christelle; Paré, David

    2017-04-01

    At the northernmost extent of the managed forest in Quebec, the boreal forest is currently undergoing an ecological transition from closed-canopy black spruce-moss forests towards open-canopy lichen woodlands, which spread southward. Our study aim was to determine whether this shift could impact soil properties on top of its repercussions on forest productivity or carbon storage. We studied the soil biogeochemical composition of three pedological layers in moss forests (MF) and lichen woodlands (LW) north of the Manicouagan crater in Quebec. The humus layer (FH horizons) was significantly thicker and held more carbon, nitrogen and exchangeable Ca and Mg in MF plots than in LW plots. When considering mineral horizons, we found that the deep C horizon had a very close composition in both ecosystem plots, suggesting that the parent material was of similar geochemical nature. This was expected as all selected sites developed from glacial deposit. Multivariate analysis of surficial mineral B horizon showed however that LW B horizon displayed higher concentrations of Al and Fe oxides than MF B horizon, particularly for inorganic amorphous forms. Conversely, main exchangeable base cations (Ca, Mg) were higher in B horizon of MF than that of LW. Ecosystem types explained much of the variations in the B horizon geochemical composition. We thus suggest that the differences observed in the geochemical composition of the B horizon have a biological origin rather than a mineralogical origin. We also showed that total net stocks of carbon stored in MF soils were three times higher than in LW soils (FH + B horizons, roots apart). Altogether, we suggest that variations in soil properties between MF and LW are linked to a cascade of events involving the impacts of natural disturbances such as wildfires on forest regeneration that determines the of vegetation structure (stand density) and composition (ground cover type) and their subsequent consequences on soil environmental

  17. The variations of aluminium species in mountainous forest soils and its implications to soil acidification.

    Science.gov (United States)

    Bradová, Monika; Tejnecký, Václav; Borůvka, Luboš; Němeček, Karel; Ash, Christopher; Šebek, Ondřej; Svoboda, Miroslav; Zenáhlíková, Jitka; Drábek, Ondřej

    2015-11-01

    Aluminium (Al) speciation is a characteristic that can be used as a tool for describing the soil acidification process. The question that was answered is how tree species (beech vs spruce) and type of soil horizon affect Al speciation. Our hypotesis is that spruce and beech forest vegetation are able to modify the chemical characteristics of organic horizon, hence the content of Al species. Moreover, these characteristics are seasonally dependent. To answer these questions, a detailed chromatographic speciation of Al in forest soils under contrasting tree species was performed. The Jizera Mountains area (Czech Republic) was chosen as a representative mountainous soil ecosystem. A basic forestry survey was performed on the investigated area. Soil and precipitation samples (throughfall, stemflow) were collected under both beech and spruce stands at monthly intervals from April to November during the years 2008-2011. Total aluminium content and Al speciation, pH, and dissolved organic carbon were determined in aqueous soil extracts and in precipitation samples. We found that the most important factors affecting the chemistry of soils, hence content of the Al species, are soil horizons and vegetation cover. pH strongly affects the amount of Al species under both forests. Fermentation (F) and humified (H) organic horizons contain a higher content of water extractable Al and Al(3+) compared to organo-mineral (A) and mineral horizons (B). With increasing soil profile depth, the amount of water extractable Al, Al(3+) and moisture decreases. The prevailing water-extractable species of Al in all studied soils and profiles under both spruce and beech forests were organically bound monovalent Al species. Distinct seasonal variations in organic and mineral soil horizons were found under both spruce and beech forests. Maximum concentrations of water-extractable Al and Al(3+) were determined in the summer, and the lowest in spring.

  18. Topology of Event Horizon

    OpenAIRE

    Siino, Masaru

    1997-01-01

    The topologies of event horizons are investigated. Considering the existence of the endpoint of the event horizon, it cannot be differentiable. Then there are the new possibilities of the topology of the event horizon though they are excluded in smooth event horizons. The relation between the topology of the event horizon and the endpoint of it is revealed. A torus event horizon is caused by two-dimensional endpoints. One-dimensional endpoints provide the coalescence of spherical event horizo...

  19. Horizon measures

    KAUST Repository

    Zhang, Eugene

    2016-11-28

    In this paper we seek to answer the following question: where do contour lines and visible contour lines (silhouette) tend to occur in a 3D surface. Our study leads to two novel shape descriptors, the horizon measure and the visible horizon measure, which we apply to the visualization of 3D shapes including archeological artifacts. In addition to introducing the shape descriptors, we also provide a closed-form formula for the horizon measure based on classical spherical geometry. To compute the visible horizon measure, which depends on the exact computation of the surface visibility function, we instead of provide an image-based approach which can process a model with high complexity within a few minutes.

  20. Benchmark values for forest soil carbon stocks in Europe

    DEFF Research Database (Denmark)

    De Vos, Bruno; Cools, Nathalie; Ilvesniemi, Hannu

    2015-01-01

    Soil organic carbon (SOC) stocks in forest floors and in mineral and peat forest soils were estimated at the European scale. The assessment was based on measured C concentration, bulk density, coarse fragments and effective soil depth data originating from 4914 plots in 22 EU countries belonging...... to the UN/ECE ICP Forests 16 × 16 km Level I network. Plots were sampled and analysed according to harmonized methods during the 2nd European Forest Soil Condition Survey. Using continuous carbon density depth functions, we estimated SOC stocks to 30-cm and 1-m depth, and stratified these stocks according...... to 22 WRB Reference Soil Groups (RSGs) and 8 humus forms to provide European scale benchmark values. Average SOC stocks amounted to 22.1 t C ha− 1 in forest floors, 108 t C ha− 1 in mineral soils and 578 t C ha− 1 in peat soils, to 1 m depth. Relative to 1-m stocks, the vertical SOC distribution...

  1. Functional assays and metagenomic analyses reveals differences between the microbial communities inhabiting the soil horizons of a Norway spruce plantation.

    Directory of Open Access Journals (Sweden)

    Stéphane Uroz

    Full Text Available In temperate ecosystems, acidic forest soils are among the most nutrient-poor terrestrial environments. In this context, the long-term differentiation of the forest soils into horizons may impact the assembly and the functions of the soil microbial communities. To gain a more comprehensive understanding of the ecology and functional potentials of these microbial communities, a suite of analyses including comparative metagenomics was applied on independent soil samples from a spruce plantation (Breuil-Chenue, France. The objectives were to assess whether the decreasing nutrient bioavailability and pH variations that naturally occurs between the organic and mineral horizons affects the soil microbial functional biodiversity. The 14 Gbp of pyrosequencing and Illumina sequences generated in this study revealed complex microbial communities dominated by bacteria. Detailed analyses showed that the organic soil horizon was significantly enriched in sequences related to Bacteria, Chordata, Arthropoda and Ascomycota. On the contrary the mineral horizon was significantly enriched in sequences related to Archaea. Our analyses also highlighted that the microbial communities inhabiting the two soil horizons differed significantly in their functional potentials according to functional assays and MG-RAST analyses, suggesting a functional specialisation of these microbial communities. Consistent with this specialisation, our shotgun metagenomic approach revealed a significant increase in the relative abundance of sequences related glycoside hydrolases in the organic horizon compared to the mineral horizon that was significantly enriched in glycoside transferases. This functional stratification according to the soil horizon was also confirmed by a significant correlation between the functional assays performed in this study and the functional metagenomic analyses. Together, our results suggest that the soil stratification and particularly the soil resource

  2. Management impacts on forest floor and soil organic carbon in northern temperate forests of the US

    Science.gov (United States)

    Coeli M. Hoover

    2011-01-01

    The role of forests in the global carbon cycle has been the subject of a great deal of research recently, but the impact of management practices on forest soil dynamics at the stand level has received less attention. This study used six forest management experimental sites in five northern states of the US to investigate the effects of silvicultural treatments (light...

  3. Magnetic Measurements as a Useful Tool for the Evaluation of Spatial Variability of the Arable Horizon Thickness

    Science.gov (United States)

    Fattakhova, Leysan; Shinkarev, Alexandr; Ryzhikh, Lyudmila; Kosareva, Lina

    2017-04-01

    In normal practice, the thickness of the arable horizon is determined on the basis of field morphological descriptions, allowing the subjectivity of perception and judgment at the crucial role of experience of the researcher. The subject of special interest are independent analytical and technically relatively simple in design approaches to the diagnosis of the lower boundary of the blended plowing the profiles part. Theoretical premises to use spectrophotometry and magnetometry to arable horizon depth diagnose is based on the concept of regular color and magnetic properties vertical differentiation in a profile of virgin soils. This work is devoted to the comparative assessment of the possibility to objectively and reliably diagnose the lower boundary of the arable horizon in gray forest soils by determining the color characteristics and the magnetic susceptibility of their layer-wise samples. It was shown with arable gray forest soil (Cutanic Luvisols (Anthric)) as example that the magnetic susceptibility profile distribution curves can provide more reliable and objective assessment of the arable horizon thickness spatial variability than the profile curves of the color characteristics in the CIELAB coordinates. Therefore, magnetic measurements can be a useful tool for the tillage erosion estimation in the monitoring of soil characteristics in connection with the development of precision agriculture technologies and the organizing of agricultural field plot experiments.

  4. Mixed Conifer Forest Duff Consumption during Prescribed Fires: Tree Crown Impacts

    NARCIS (Netherlands)

    Hille, M.G.; Stephens, S.L.

    2005-01-01

    Fire suppression has produced large forest floor fuel loads in many coniferous forests in western North America. This study describes spatial patterns of duff consumption in a mixed-conifer forest in the north-central Sierra Nevada, California. Overstory crown coverage was correlated to spatial

  5. Parity horizons in shape dynamics

    International Nuclear Information System (INIS)

    Herczeg, Gabriel

    2016-01-01

    I introduce the notion of a parity horizon, and show that many simple solutions of shape dynamics possess them. I show that the event horizons of the known asymptotically flat black hole solutions of shape dynamics are parity horizons and that this notion of parity implies that these horizons possess a notion of CPT invariance that can in some cases be extended to the solution as a whole. I present three new solutions of shape dynamics with parity horizons and find that not only do event horizons become parity horizons in shape dynamics, but observer-dependent horizons and Cauchy horizons do as well. The fact that Cauchy horizons become (singular) parity horizons suggests a general chronology protection mechanism in shape dynamics that prevents the formation of closed timelike curves. (paper)

  6. Variation in carbon storage and its distribution by stand age and forest type in boreal and temperate forests in northeastern China.

    Science.gov (United States)

    Wei, Yawei; Li, Maihe; Chen, Hua; Lewis, Bernard J; Yu, Dapao; Zhou, Li; Zhou, Wangming; Fang, Xiangmin; Zhao, Wei; Dai, Limin

    2013-01-01

    The northeastern forest region of China is an important component of total temperate and boreal forests in the northern hemisphere. But how carbon (C) pool size and distribution varies among tree, understory, forest floor and soil components, and across stand ages remains unclear. To address this knowledge gap, we selected three major temperate and two major boreal forest types in northeastern (NE) China. Within both forest zones, we focused on four stand age classes (young, mid-aged, mature and over-mature). Results showed that total C storage was greater in temperate than in boreal forests, and greater in older than in younger stands. Tree biomass C was the main C component, and its contribution to the total forest C storage increased with increasing stand age. It ranged from 27.7% in young to 62.8% in over-mature stands in boreal forests and from 26.5% in young to 72.8% in over-mature stands in temperate forests. Results from both forest zones thus confirm the large biomass C storage capacity of old-growth forests. Tree biomass C was influenced by forest zone, stand age, and forest type. Soil C contribution to total forest C storage ranged from 62.5% in young to 30.1% in over-mature stands in boreal and from 70.1% in young to 26.0% in over-mature in temperate forests. Thus soil C storage is a major C pool in forests of NE China. On the other hand, understory and forest floor C jointly contained less than 13% and forests respectively, and thus play a minor role in total forest C storage in NE China.

  7. Dynamic of radionuclides behaviour in forest soils

    International Nuclear Information System (INIS)

    Ruehm, W.; Steiner, M.; Wirth, E.; Dvornik, A.; Zhuchenko, T.A.; Kliashtorin, A.; Rafferty, B.; Shaw, G.; Kuchma, N.

    1996-01-01

    Within the research project ECP-5, the dynamics of radionuclides in automorphic forest soils within the 30-km-zone of Chernobyl and of hydromorphic forest soils in Belarus have been investigated. In upland forest soils, the lower layers of the organic horizons are characterized by the highest residence times for radiocesium and represent the largest pool for all radionuclides investigated. According to a preliminary estimate, radiocesium is more mobile compared to 125 Sb, which in turn migrates faster than 60 Co, 144 Ce, and 154 Eu. 106 Ru shows the lowest mobility. With regard to radiocesium, hydromorphic soils exhibit migration rates and transfer factors from soil to trees, which by far exceed those in automorphic soils. Based on a two-component quasi-diffusional model the average bias of 137 Cs in mesotrophic swamp soils was predicted. The activity concentrations of U, Pu, and Cs suggest that U and Pu were originally deposited as hot particles and that U is naturally accumulated in organic horizons

  8. Ground-fire effects on the composition of dissolved and total organic matter in forest floor and soil solutions from Scots pine forests in Germany: new insights from solid state 13C NMR analysis

    Science.gov (United States)

    Näthe, Kerstin; Michalzik, Beate; Levia, Delphis; Steffens, Markus

    2016-04-01

    Fires represent an ecosystem disturbance and are recognized to seriously pertubate the nutrient budgets of forested ecosystems. While the effects of fires on chemical, biological, and physical soil properties have been intensively studied, especially in Mediterranean areas and North America, few investigations examined the effects of fire-induced alterations in the water-bound fluxes and the chemical composition of dissolved and particulate organic carbon and nitrogen (DOC, POC, DN, PN). The exclusion of the particulate organic matter fraction (0.45 μm Independent from fire manipulation, the composition of TOM was generally less aromatic (aromaticity index [%] according to Hatcher et al., 1981) with values between 18 (FF) - 25% (B horizon) than the DOM fraction with 23 (FF) - 27% (B horizon). For DOM in FF solution, fire manipulation caused an increase in aromaticity from 23 to 27% compared to the control, due to an increase of the aryl-C and a decrease of the O-alkyl-C and alkyl-C signal. Fire effects were leveled out in the mineral soil. For TOM, fire effects became notable only in the A horizon, exhibiting a decrease in aromaticity from 22 to 18% compared to the control, due to increased O-alkyl-C and diminished aryl-C proportions. Compared to the control, fire only caused minor DOC release rates (events did not significantly enhance the proportion of POC and PN in the total C and N amounts exhibiting values between 10 and 20%. To fully understand the quality and amount of translocated organic C and N compounds within soils under both ambient as well as fire environments, dissolved and particulate size fractions need to be considered.

  9. SUSTAINABLE TRAILER FLOORING

    Directory of Open Access Journals (Sweden)

    John Lu

    2009-05-01

    Full Text Available Different trailer flooring materials, including wood-based, aluminum, steel, and synthetic plastic floors, were evaluated in accordance with their durability and sustainability to our natural environment. Wood-based trailer flooring is an eco-friendly product. It is the most sustainable trailer flooring material compared with fossil fuel-intensive steel, aluminum, and plastics. It is renewable and recyclable. Oak, hard maple, and apitong are strong and durable hardwood species that are currently extensively used for trailer flooring. For manufacture, wood-based flooring is higher in energy efficiency and lower in carbon emission than steel, aluminum and plastics. Moreover, wood per se is a natural product that sequesters carbon. Accordingly, using more wood-based trailer flooring is effective to reduce global warming.

  10. Aggregate Stability in Soil with Humic and Histic Horizons in a Toposequence under Araucaria Forest

    Directory of Open Access Journals (Sweden)

    Daniel Hanke

    Full Text Available ABSTRACT Aggregate stability is one of the most important factors in soil conservation and maintenance of soil environmental functions. The objective of this study was to investigate the aggregate stability mechanisms related to chemical composition of organic matter in soil profiles with humic and histic horizons in a toposequence under Araucaria moist forest in southern Brazil. The soils sampled were classified as Humic Hapludox (highest position, Fluvaquentic Humaquepts (lowest slope position, and Typic Haplosaprists (floodplain. The C and N contents were determined in bulk soil samples. The chemical composition of soil organic matter was evaluated by infrared spectroscopy. Aggregate stability was determined by applying increasing levels of ultrasound energy. Carbon content increased from the top of the slope to the alluvial plain. Higher ultrasonic energy values for clay dispersion were observed in the C-rich soils in the lower landscape positions, indicating that organic compounds play an important role in the structural stabilization of these profiles. Both aliphatic and carbohydrate-like structures were pertinent to aggregate stability. In the Oxisol, organo-mineral interaction between carbohydrates and the clay mineral surface was the most important mechanism affecting aggregation. In soils with a higher C content (Humaquepts and Haplosaprists, stabilization is predominantly conferred by the aliphatic groups, which is probably due to the structural protection offered by these hydrophobic organic groups.

  11. Phosphorus 32 cycling in the root-litter mat of Pernambuco atlantic coastal forest, Brazil

    International Nuclear Information System (INIS)

    Salcedo, I.H.; Sampaio, E.V.S.; Elliott, E.T.

    1991-01-01

    We propose a compartmental model to describe P cycling in the root-litter mat and surface mineral soil of an Atlantic coastal forest. Considerable amounts of P accumulate in this root-litter mat, relative to available P in the underlying mineral soil. We studied the mechanisms responsible for P retention five days after addition of sup(32)P on the surface of the 02 horizon. Total sup(31)P and sup(32)P were determined in leaves, humus, mineral soil and roots. In addition, we determined sup(31)P and sup(32)P in the solution and microbial biomass of the humus material. Fluxes of sup(31)P were obtained from published data and from experimental results of sup(32)P distribution among compartments. The main fluxes taking P out from the soils solution were uptake by the microbial biomass and sorption by the humus (12.9 e 5.2 mg P m sup(-2) week sup(-1), respectively), while the mean flux into the roots was 3.1 mg P m sup(-2) week sup(-1). The main compartment responsible for P accumulation was the humus+fragments, which had the highest P content (61% of total P in the forest floor) and the longest turnover time (15.5 months). (author)

  12. Predicting the spatial distribution of leaf litterfall in a mixed deciduous forest

    NARCIS (Netherlands)

    Staelens, Jeroen; Nachtergale, Lieven; Luyssaert, Sebastiaan

    2004-01-01

    An accurate prediction of the spatial distribution of litterfall can improve insight in the interaction between the canopy layer and forest floor characteristics, which is a key feature in forest nutrient cycling. Attempts to model the spatial variability of litterfall have been made across forest

  13. Floors: Selection and Maintenance.

    Science.gov (United States)

    Berkeley, Bernard

    Flooring for institutional, commercial, and industrial use is described with regard to its selection, care, and maintenance. The following flooring and subflooring material categories are discussed--(1) resilient floor coverings, (2) carpeting, (3) masonry floors, (4) wood floors, and (5) "formed-in-place floors". The properties, problems,…

  14. Organotin compounds in precipitation, fog and soils of a forested ecosystem in Germany

    International Nuclear Information System (INIS)

    Huang, J.-H.; Schwesig, David; Matzner, Egbert

    2004-01-01

    Organotin compounds (OTC) are highly toxic pollutants and have been mostly investigated so far in aquatic systems and sediments. The concentrations and fluxes of different organotin compounds, including methyl-, butyl-, and octyltin species in precipitation and fog were investigated in a forested catchment in NE Bavaria, Germany. Contents, along with the vertical distribution and storages in two upland and two wetland soils were determined. During the 1-year monitoring, the OTC concentrations in bulk deposition, throughfall and fog ranged from 1 ng Sn l -1 to several ten ng Sn l -1 , but never over 200 ng Sn l -1 . The OTC concentrations in fog were generally higher than in throughfall and bulk deposition. Mono-substituted species were the dominant Sn species in precipitation (up to 190 ng Sn l -1 ) equaling a flux of up to 70 mg Sn ha -1 a -1 . In upland soils, OTC contents peaked in the forest floor (up to 30 ng Sn g -1 ) and decreased sharply with the depth. In wetland soils, OTC had slightly higher contents in the upper horizons. The dominance of mono-substituted species in precipitation is well reflected in the contents and storages of OTC in both upland and wetland soils. The ratios of OTC soil storages to the annual throughfall flux ranged from 20 to 600 years. These high ratios are probably due to high stability and low mobility of OTC in soils. No evidence was found for methylation of tin in the wetland soils. In comparison with sediments, concentrations and contents of organotin in forest soils are considerably lower, and the dominant species are less toxic. It is concluded that forested soils may act as sinks for OTC deposited from the atmosphere. - Forested soils may act as sinks for atmospherically deposited organotin compounds

  15. How to estimate forest carbon for large areas from inventory data

    Science.gov (United States)

    James E. Smith; Linda S. Heath; Peter B. Woodbury

    2004-01-01

    Carbon sequestration through forest growth provides a low-cost approach for meeting state and national goals to reduce net accumulations of atmospheric carbon dioxide. Total forest ecosystem carbon stocks include "pools" in live trees, standing dead trees, understory vegetation, down dead wood, forest floor, and soil. Determining the level of carbon stocks in...

  16. Mechanics of apparent horizons

    International Nuclear Information System (INIS)

    Collins, W.

    1992-01-01

    An equation for the variation in the surface area of an apparent horizon is derived which has the same form as the thermodynamic relation TdS=dQ. For a stationary vacuum black hole, the expression corresponding to a temperature equals the temperature of the event horizon. Also, if the black hole is perturbed infinitesimally by weak matter and gravitational fields, the area variation of the apparent horizon asymptotically approaches the Hartle-Hawking result for the event horizon. These results support the idea that a local version of black-hole thermodynamics in nonstationary systems can be constructed for apparent horizons

  17. Long-Term Soil Chemistry Changes in Aggrading Forest Ecosystems

    Science.gov (United States)

    Jennifer D. Knoepp; Wayne T. Swank

    1994-01-01

    Assessing potential long-term forest productivity requires identification of the processes regulating chemical changes in forest soils. We resampled the litter layer and upper two mineral soil horizons, A and AB/BA, in two aggrading southern Appalachian watersheds 20 yr after an earlier sampling. Soils from a mixed-hardwood watershed exhibited a small but significant...

  18. Unearthing Secrets of the Forest

    Science.gov (United States)

    Beldin, Sarah I.; Perakis, Steven S.

    2009-01-01

    Forests are a defining feature for large areas of the Pacific northwestern United States from northern California to Alaska. Coniferous temperate rainforests in the western Cascade and coastal mountain ranges are appreciated for their aesthetic value and abundant natural resources. Few people recognize the riches beneath the forest floor; yet, soil is a key ecosystem component that makes each type of forest unique. Soils harbor immense biological diversity and control the release of water and nutrients that support life above ground. Understanding how carbon and nutrients cycle in forests, known as forest biogeochemistry, is crucial for evaluating forest productivity, composition, diversity, and change. At the U.S. Geological Survey (USGS) Forest and Rangeland Ecosystem Science Center, research in the Terrestrial Ecosystems Laboratory focuses on nutrient cycling in five themes: climate change, nutrition and sustainability, fire effects, restoration, and forest-stream linkages. This research is essential to understand the entire forest ecosystem and to use the best science available to make informed policy and management decisions.

  19. Leaching of nitrate from temperate forests - effects of air pollution and forest management

    DEFF Research Database (Denmark)

    Gundersen, Per; Schmidt, Inger Kappel; Raulund-Rasmussen, Karsten

    2006-01-01

    deposition (> 8-10 kg ha(-1) a(-1)). We synthesized the current understanding of factors controlling N leaching in relation to three primary causes of N cycle disruption: (i) Increased N input (air pollution, fertilization, N-2 fixing plants). In European forests, elevated N deposition explains approximately...... half of the variability in N leaching, some of the remaining variability could be explained by differences in N availability or "N status". For coniferous forests, needle N content above 1.4% and (or) forest floor C:N ratio lower than 25 were thresholds for elevated nitrate leaching. At adjacent sites...... conifer forests receive higher N deposition and exhibit higher nitrate loss than deciduous forests; an exception is alder that shows substantial nitrate leaching through N fixation input. Fertilization with N poses limited risk to water quality, when applied to N-limited forests. (ii) Reduced plant uptake...

  20. Age of North Island giant moa (Dinornis novaezealandiae) bones found on the forest floor in the Ruahine Range

    International Nuclear Information System (INIS)

    Wood, J.R.; Wilmshurst, J.M.

    2013-01-01

    During the nineteenth century, multiple discoveries of moa bones lying on the ground surface in exposed situations generated debate about the recentness of moa extinction. Subsequently, clearance of land for agricultural purposes has probably resulted in the destruction of many surface moa bones and such finds are now rare. The recent discovery of a pair of tibiotarsi from a North Island giant moa (Dinornis novaezealandiae) lying on the forest floor at Aorangi Awarua, Ruahine Range, has allowed the age of two surface moa bones to be tested. Both tibiotarsi were AMS radiocarbon dated and returned ages of 681±28 and 721±29 14C years BP. The 2σ calibrated ranges are statistically the same age and suggest that the bones are from one bird that died sometime between AD 1286 and 1390. Although the bones post-date human settlement of New Zealand, they are not anomalously recent. The results show that, given favourable environmental conditions, moa bones can persist in exposed situations for long periods, and do not necessarily reflect survival of moa into relatively recent times. (author)

  1. Pelvic floor muscle function in women with pelvic floor dysfunction

    DEFF Research Database (Denmark)

    Tibaek, Sigrid; Dehlendorff, Christian

    2014-01-01

    The objectives of this study were to investigate the level of pelvic floor muscle (PFM) function in women with pelvic floor dysfunction (PFD) referred by gynaecologists and urologists for in-hospital pelvic floor muscle training (PFMT), and to identity associated factors for a low level of PFM...

  2. SUSTAINABLE TRAILER FLOORING

    OpenAIRE

    John Lu; Marc Chorney; Lowell Peterson

    2009-01-01

    Different trailer flooring materials, including wood-based, aluminum, steel, and synthetic plastic floors, were evaluated in accordance with their durability and sustainability to our natural environment. Wood-based trailer flooring is an eco-friendly product. It is the most sustainable trailer flooring material compared with fossil fuel-intensive steel, aluminum, and plastics. It is renewable and recyclable. Oak, hard maple, and apitong are strong and durable hardwood species that are curren...

  3. Nutritional hotspots and the secret life of forests

    Science.gov (United States)

    Jane Smith; Laurel Kluber; Noreen Parks

    2014-01-01

    The floor of a Douglas-fir forest may be rich in organic matter, but nutrients essential to plant growth are locked within the decomposing needles, leaves, and fallen wood. Before nitrogen, phosphorus, and other nutrients can be cycled back through the forest system, they need to be further broken down into forms accessible to plants. Understanding how nutrients become...

  4. [The concentration and distribution of 137Cs in soils of forest and agricultural ecosystems of Tula Region].

    Science.gov (United States)

    Lipatov, D N; Shcheglov, A I; Tsvetnova, O B

    2007-01-01

    The paper deals with a comparative study of 137Cs contamination in forest, old arable and cultivated soils of Tula Region. Initial interception of Chernobyl derived 137Cs is higher in forest ecosystems: oak-forest > birch-forest > pine-forest > agricultural ecosystems. Vertical migration of 137Cs in deeper layers of soils was intensive in agricultural ecosystems: cultivated soils > old arable soils > birch-forest soils > oak-forest soils > pine-forest soils. In study have been evaluated spatial variability of 137Cs in soil and asymmetrical distribution, that is a skew to the right. Spatial heterogeneity of 137Cs in agricultural soils is much lower than in forest soils. For cultivated soil are determined the rate of resuspension, which equal to 6.1 x 10(-4) day(-1). For forest soils are described the 137Cs concentration in litter of different ecosystems. The role of main accumulation and barrier of 137Cs retain higher layers of soils (horizon A1(A1E) in forest, horizon Ap in agricultural ecosystems) in long-term forecast after Chernobyl accident.

  5. Seasonal changes in camera-based indices from an open canopy black spruce forest in Alaska, and comparison with indices from a closed canopy evergreen coniferous forest in Japan

    Science.gov (United States)

    Nagai, Shin; Nakai, Taro; Saitoh, Taku M.; Busey, Robert C.; Kobayashi, Hideki; Suzuki, Rikie; Muraoka, Hiroyuki; Kim, Yongwon

    2013-06-01

    Evaluation of the carbon, water, and energy balances in evergreen coniferous forests requires accurate in situ and satellite data regarding their spatio-temporal dynamics. Daily digital camera images can be used to determine the relationships among phenology, gross primary productivity (GPP), and meteorological parameters, and to ground-truth satellite observations. In this study, we examine the relationship between seasonal variations in camera-based canopy surface indices and eddy-covariance-based GPP derived from field studies in an Alaskan open canopy black spruce forest and in a Japanese closed canopy cedar forest. The ratio of the green digital number to the total digital number, hue, and GPP showed a bell-shaped seasonal profile at both sites. Canopy surface images for the black spruce forest and cedar forest mainly detected seasonal changes in vegetation on the floor of the forest and in the tree canopy, respectively. In contrast, the seasonal cycles of the ratios of the red and blue digital numbers to the total digital numbers differed between the two sites, possibly due to differences in forest structure and leaf color. These results suggest that forest structural characteristics, such as canopy openness and seasonal forest-floor changes, should be considered during continuous observations of phenology in evergreen coniferous forests.

  6. DOM composition and transformation in boreal forest soils: The effects of temperature and organic-horizon decomposition state

    Science.gov (United States)

    O’Donnell, Jonathan A.; Aiken, George R.; Butler, Kenna D.; Guillemette, Francois; Podgorski, David C.; Spencer, Robert G. M.

    2016-01-01

    The boreal region stores large amounts of organic carbon (C) in organic-soil horizons, which are vulnerable to destabilization via warming and disturbance. Decomposition of soil organic matter (SOM) contributes to the production and turnover of dissolved organic matter (DOM). While temperature is a primary control on rates of SOM and DOM cycling, little is known about temperature effects on DOM composition in soil leachate. Here we conducted a 30 day incubation to examine the effects of temperature (20 versus 5°C) and SOM decomposition state (moss versus fibric versus amorphous horizons) on DOM composition in organic soils of interior Alaska. We characterized DOM using bulk dissolved organic C (DOC) concentration, chemical fractionation, optical properties, and ultrahigh-resolution mass spectrometry. We observed an increase in DOC concentration and DOM aromaticity in the 20°C treatment compared to the 5°C treatment. Leachate from fibric horizons had higher DOC concentration than shallow moss or deep amorphous horizons. We also observed chemical shifts in DOM leachate over time, including increases in hydrophobic organic acids, polyphenols, and condensed aromatics and decreases in low-molecular weight hydrophilic compounds and aliphatics. We compared ultrahigh-resolution mass spectrometry and optical data and observed strong correlations between polyphenols, condensed aromatics, SUVA254, and humic-like fluorescence intensities. These findings suggest that biolabile DOM was preferentially mineralized, and the magnitude of this transformation was determined by kinetics (i.e., temperature) and substrate quality (i.e., soil horizon). With future warming, our findings indicate that organic soils may release higher concentrations of aromatic DOM to aquatic ecosystems.

  7. Abiotic and Biotic Soil Characteristics in Old Growth Forests and Thinned or Unthinned Mature Stands in Three Regions of Oregon

    Directory of Open Access Journals (Sweden)

    David A. Perry

    2012-09-01

    Full Text Available We compared forest floor depth, soil organic matter, soil moisture, anaerobic mineralizable nitrogen (a measure of microbial biomass, denitrification potential, and soil/litter arthropod communities among old growth, unthinned mature stands, and thinned mature stands at nine sites (each with all three stand types distributed among three regions of Oregon. Mineral soil measurements were restricted to the top 10 cm. Data were analyzed with both multivariate and univariate analyses of variance. Multivariate analyses were conducted with and without soil mesofauna or forest floor mesofauna, as data for those taxa were not collected on some sites. In multivariate analysis with soil mesofauna, the model giving the strongest separation among stand types (P = 0.019 included abundance and richness of soil mesofauna and anaerobic mineralizable nitrogen. The best model with forest floor mesofauna (P = 0.010 included anaerobic mineralizable nitrogen, soil moisture content, and richness of forest floor mesofauna. Old growth had the highest mean values for all variables, and in both models differed significantly from mature stands, while the latter did not differ. Old growth also averaged higher percent soil organic matter, and analysis including that variable was significant but not as strong as without it. Results of the multivariate analyses were mostly supported by univariate analyses, but there were some differences. In univariate analysis, the difference in percent soil organic matter between old growth and thinned mature was due to a single site in which the old growth had exceptionally high soil organic matter; without that site, percent soil organic matter did not differ between old growth and thinned mature, and a multivariate model containing soil organic matter was not statistically significant. In univariate analyses soil mesofauna had to be compared nonparametrically (because of heavy left-tails and differed only in the Siskiyou Mountains, where

  8. Foliar and soil chemistry at red spruce sites in the Monongahela National Forest

    Science.gov (United States)

    Stephanie J. Connolly

    2010-01-01

    In 2005, soil and foliar chemistry were sampled from 10 sites in the Monongahela National Forest which support red spruce. Soils were sampled from hand-dug pits, by horizon, from the O-horizon to bedrock or 152 cm, and each pit was described fully. Replicate, archived samples also were collected.

  9. Revisiting event horizon finders

    International Nuclear Information System (INIS)

    Cohen, Michael I; Pfeiffer, Harald P; Scheel, Mark A

    2009-01-01

    Event horizons are the defining physical features of black hole spacetimes, and are of considerable interest in studying black hole dynamics. Here, we reconsider three techniques to find event horizons in numerical spacetimes: integrating geodesics, integrating a surface, and integrating a level-set of surfaces over a volume. We implement the first two techniques and find that straightforward integration of geodesics backward in time is most robust. We find that the exponential rate of approach of a null surface towards the event horizon of a spinning black hole equals the surface gravity of the black hole. In head-on mergers we are able to track quasi-normal ringing of the merged black hole through seven oscillations, covering a dynamic range of about 10 5 . Both at late times (when the final black hole has settled down) and at early times (before the merger), the apparent horizon is found to be an excellent approximation of the event horizon. In the head-on binary black hole merger, only some of the future null generators of the horizon are found to start from past null infinity; the others approach the event horizons of the individual black holes at times far before merger.

  10. Establishment of ectomycorrhizal fungal community on isolated Nothofagus cunninghamii seedlings regenerating on dead wood in Australian wet temperate forests: does fruit-body type matter?

    Science.gov (United States)

    Tedersoo, Leho; Gates, Genevieve; Dunk, Chris W; Lebel, Teresa; May, Tom W; Kõljalg, Urmas; Jairus, Teele

    2009-08-01

    Decaying wood provides an important habitat for animals and forms a seed bed for many shade-intolerant, small-seeded plants, particularly Nothofagus. Using morphotyping and rDNA sequence analysis, we compared the ectomycorrhizal fungal community of isolated N. cunninghamii seedlings regenerating in decayed wood against that of mature tree roots in the forest floor soil. The /cortinarius, /russula-lactarius, and /laccaria were the most species-rich and abundant lineages in forest floor soil in Australian sites at Yarra, Victoria and Warra, Tasmania. On root tips of seedlings in dead wood, a subset of the forest floor taxa were prevalent among them species of /laccaria, /tomentella-thelephora, and /descolea, but other forest floor dominants were rare. Statistical analyses suggested that the fungal community differs between forest floor soil and dead wood at the level of both species and phylogenetic lineage. The fungal species colonizing isolated seedlings on decayed wood in austral forests were taxonomically dissimilar to the species dominating in similar habitats in Europe. We conclude that formation of a resupinate fruit body type on the underside of decayed wood is not necessarily related to preferential root colonization in decayed wood. Rather, biogeographic factors as well as differential dispersal and competitive abilities of fungal taxa are likely to play a key role in structuring the ectomycorrhizal fungal community on isolated seedlings in decaying wood.

  11. 78 FR 54298 - Horizons ETFs Management (USA) LLC and Horizons ETF Trust; Notice of Application

    Science.gov (United States)

    2013-09-03

    ... ETFs Management (USA) LLC and Horizons ETF Trust; Notice of Application August 27, 2013. AGENCY... Management (USA) LLC (``Horizons'') and Horizons ETF Trust (the ``Trust''). Summary of Application... of the Trust will be the Horizons Active Global Dividend ETF (the ``Initial Fund''), which will seek...

  12. Soils of Mountainous Forests and Their Transformation under the Impact of Fires in Baikal Region

    Science.gov (United States)

    Krasnoshchekov, Yu. N.

    2018-04-01

    Data on postpyrogenic dynamics of soils under mountainous taiga cedar ( Pinus sibirica) and pine ( Pinus sylvestris) forests and subtaiga-forest-steppe pine ( Pinus sylvestris) forests in the Baikal region are analyzed. Ground litter-humus fires predominating in this region transform the upper diagnostic organic soil horizons and lead to the formation of new pyrogenic organic horizons (Opir). Adverse effects of ground fires on the stock, fractional composition, and water-physical properties of forest litters are shown. Some quantitative parameters of the liquid and solid surface runoff in burnt areas related to the slope gradient, fire intensity, and the time passed after the fire are presented. Pyrogenic destruction of forest ecosystems inevitably induces the degradation of mountainous soils, whose restoration after fires takes tens of years. The products of soil erosion from the burnt out areas complicate the current situation with the pollution of coastal waters of Lake Baikal.

  13. Seasonality and structure of the arthropod community in a forested ...

    African Journals Online (AJOL)

    The structure of an arthropod community in the forest floor vegetation was studied in a low altitude (about 700 m a.s.l.) forest valley in the Uluguru Mountains near Morogoro, Tanzania, by monthly sweep net sampling during one year (December 1996-November 1997). The community structure of arthropods changed ...

  14. What happens at the horizon(s) of an extreme black hole?

    International Nuclear Information System (INIS)

    Murata, Keiju; Reall, Harvey S; Tanahashi, Norihiro

    2013-01-01

    A massless scalar field exhibits an instability at the event horizon of an extreme black hole. We study numerically the nonlinear evolution of this instability for spherically symmetric perturbations of an extreme Reissner–Nordstrom (RN) black hole. We find that generically the endpoint of the instability is a non-extreme RN solution. However, there exist fine-tuned initial perturbations for which the instability never decays. In this case, the perturbed spacetime describes a time-dependent extreme black hole. Such solutions settle down to extreme RN outside, but not on, the event horizon. The event horizon remains smooth but certain observers who cross it at late time experience large gradients there. Our results indicate that these dynamical extreme black holes admit a C 1 extension across an inner (Cauchy) horizon. (paper)

  15. Interpreting the deposition and vertical migration characteristics of 137Cs in forest soil after the Fukushima Dai-ichi Nuclear Power Plant accident.

    Science.gov (United States)

    Kang, Seongjoo; Yoneda, Minoru; Shimada, Yoko; Satta, Naoya; Fujita, Yasutaka; Shin, In Hwan

    2017-08-01

    We investigated the deposition and depth distributions of radiocesium in the Takizawa Research Forest, Iwate Prefecture, in order to understand the behavior of radionuclides released from the Fukushima Dai-ichi Nuclear Power Plant. The deposition distribution and vertical depth distribution of radiocesium in the soil were compared between topographically distinct parts of the forest where two different tree species grow. The results for all investigated locations show that almost 85% of the radiocesium has accumulated in the region of soil from the topmost organic layer to a soil depth of 0-4 cm. However, no activity was detected at depths greater than 20 cm. Analysis of the radiocesium deposition patterns in forest locations dominated by either coniferous or deciduous tree species suggests that radiocesium was sequestered and retained in higher concentrations in coniferous areas. The deposition data showed large spatial variability, reflecting the differences in tree species and topography. The variations in the measured 137 Cs concentrations reflected the variability in the characteristics of the forest floor environment and the heterogeneity of the initial ground-deposition of the Fukushima fallout. Sequential extraction experiments showed that most of the 137 Cs was present in an un-exchangeable form with weak mobility. Nevertheless, the post-vertical distribution of 137 Cs is expected to be governed by the percentage of exchangeable 137 Cs in the organic layer and the organic-rich upper soil horizons.

  16. Spacetimes foliated by Killing horizons

    International Nuclear Information System (INIS)

    Pawlowski, Tomasz; Lewandowski, Jerzy; Jezierski, Jacek

    2004-01-01

    It seems to be expected that a horizon of a quasi-local type, such as a Killing or an isolated horizon, by analogy with a globally defined event horizon, should be unique in some open neighbourhood in the spacetime, provided the vacuum Einstein or the Einstein-Maxwell equations are satisfied. The aim of our paper is to verify whether that intuition is correct. If one can extend a so-called Kundt metric, in such a way that its null, shear-free surfaces have spherical spacetime sections, the resulting spacetime is foliated by so-called non-expanding horizons. The obstacle is Kundt's constraint induced at the surfaces by the Einstein or the Einstein-Maxwell equations, and the requirement that a solution be globally defined on the sphere. We derived a transformation (reflection) that creates a solution to Kundt's constraint out of data defining an extremal isolated horizon. Using that transformation, we derived a class of exact solutions to the Einstein or Einstein-Maxwell equations of very special properties. Each spacetime we construct is foliated by a family of the Killing horizons. Moreover, it admits another, transversal Killing horizon. The intrinsic and extrinsic geometries of the transversal Killing horizon coincide with the one defined on the event horizon of the extremal Kerr-Newman solution. However, the Killing horizon in our example admits yet another Killing vector tangent to and null at it. The geometries of the leaves are given by the reflection

  17. Tree species is the major factor explaining C:N ratios in European forest soils

    DEFF Research Database (Denmark)

    Cools, Nathalie; Vesterdal, Lars; De Vos, Bruno

    2014-01-01

    The C:N ratio is considered as an indicator of nitrate leaching in response to high atmospheric nitrogen (N) deposition. However, the C:N ratio is influenced by a multitude of other site-related factors. This study aimed to unravel the factors determining C:N ratios of forest floor, mineral soil...... mineral soil layers it was the humus type. Deposition and climatic variables were of minor importance at the European scale. Further analysis for eight main forest tree species individually, showed that the influence of environmental variables on C:N ratios was tree species dependent. For Aleppo pine...... and peat top soils in more than 4000 plots of the ICP Forests large-scale monitoring network. The first objective was to quantify forest floor, mineral and peat soil C:N ratios across European forests. Secondly we determined the main factors explaining this C:N ratio using a boosted regression tree...

  18. Temporal changes in radiocesium deposition in various forest stands following the Fukushima Dai-ichi Nuclear Power Plant accident.

    Science.gov (United States)

    Kato, Hiroaki; Onda, Yuichi; Hisadome, Keigo; Loffredo, Nicolas; Kawamori, Ayumi

    2017-01-01

    In this study, we investigated the transfer of canopy-intercepted radiocesium to the forest floor following the Fukushima Dai-ichi Nuclear Power Plant accident. The 137 Cs content of throughfall, stemflow, and litterfall were monitored in two coniferous stands (plantations of Japanese cedar) and a deciduous mixed broad-leaved forest stand (oak with red pine) from July 2011 to December 2012. The forest floor of cedar stands had received higher levels of additional 137 Cs deposition compared with the mixed broad-leaved stand during the sampling period. The cumulative 137 Cs deposition during the study period was 119 kBq m -2 for the mature cedar stand, 105 kBq m -2 for the young cedar stand, and 41.5 kBq m -2 for the broad-leaved stand. The deposition of 137 Cs to the forest floor occurred mainly in throughfall during the first rainy season, from July to September 2011 (<200 d after the initial fallout); thereafter, the transfer of 137 Cs from the canopy to forest floor occurred mainly through litterfall. A double exponential field-loss model, which was used to simulate the removal of 137 Cs from canopies, was the best fit for the temporal changes in the canopy 137 Cs inventory. Copyright © 2015 Elsevier Ltd. All rights reserved.

  19. Boreal coniferous forest density leads to significant variations in soil physical and geochemical properties

    Science.gov (United States)

    Bastianelli, Carole; Ali, Adam A.; Beguin, Julien; Bergeron, Yves; Grondin, Pierre; Hély, Christelle; Paré, David

    2017-07-01

    At the northernmost extent of the managed forest in Quebec, Canada, the boreal forest is currently undergoing an ecological transition between two forest ecosystems. Open lichen woodlands (LW) are spreading southward at the expense of more productive closed-canopy black spruce-moss forests (MF). The objective of this study was to investigate whether soil properties could distinguish MF from LW in the transition zone where both ecosystem types coexist. This study brings out clear evidence that differences in vegetation cover can lead to significant variations in soil physical and geochemical properties.Here, we showed that soil carbon, exchangeable cations, and iron and aluminium crystallinity vary between boreal closed-canopy forests and open lichen woodlands, likely attributed to variations in soil microclimatic conditions. All the soils studied were typical podzolic soil profiles evolved from glacial till deposits that shared a similar texture of the C layer. However, soil humus and the B layer varied in thickness and chemistry between the two forest ecosystems at the pedon scale. Multivariate analyses of variance were used to evaluate how soil properties could help distinguish the two types at the site scale. MF humus (FH horizons horizons composing the O layer) showed significantly higher concentrations of organic carbon and nitrogen and of the main exchangeable base cations (Ca, Mg) than LW soils. The B horizon of LW sites held higher concentrations of total Al and Fe oxides and particularly greater concentrations of inorganic amorphous Fe oxides than MF mineral soils, while showing a thinner B layer. Overall, our results show that MF store three times more organic carbon in their soils (B+FH horizons, roots apart) than LW. We suggest that variations in soil properties between MF and LW are linked to a cascade of events involving the impacts of natural disturbances such as wildfires on forest regeneration that determines the vegetation structure (stand density

  20. Boreal coniferous forest density leads to significant variations in soil physical and geochemical properties

    Directory of Open Access Journals (Sweden)

    C. Bastianelli

    2017-07-01

    Full Text Available At the northernmost extent of the managed forest in Quebec, Canada, the boreal forest is currently undergoing an ecological transition between two forest ecosystems. Open lichen woodlands (LW are spreading southward at the expense of more productive closed-canopy black spruce–moss forests (MF. The objective of this study was to investigate whether soil properties could distinguish MF from LW in the transition zone where both ecosystem types coexist. This study brings out clear evidence that differences in vegetation cover can lead to significant variations in soil physical and geochemical properties.Here, we showed that soil carbon, exchangeable cations, and iron and aluminium crystallinity vary between boreal closed-canopy forests and open lichen woodlands, likely attributed to variations in soil microclimatic conditions. All the soils studied were typical podzolic soil profiles evolved from glacial till deposits that shared a similar texture of the C layer. However, soil humus and the B layer varied in thickness and chemistry between the two forest ecosystems at the pedon scale. Multivariate analyses of variance were used to evaluate how soil properties could help distinguish the two types at the site scale. MF humus (FH horizons horizons composing the O layer showed significantly higher concentrations of organic carbon and nitrogen and of the main exchangeable base cations (Ca, Mg than LW soils. The B horizon of LW sites held higher concentrations of total Al and Fe oxides and particularly greater concentrations of inorganic amorphous Fe oxides than MF mineral soils, while showing a thinner B layer. Overall, our results show that MF store three times more organic carbon in their soils (B+FH horizons, roots apart than LW. We suggest that variations in soil properties between MF and LW are linked to a cascade of events involving the impacts of natural disturbances such as wildfires on forest regeneration that determines the vegetation

  1. Tree species and soil nutrient profiles in old-growth forests of the Oregon Coast Range

    Science.gov (United States)

    Cross, Alison; Perakis, Steven S.

    2011-01-01

    Old-growth forests of the Pacific Northwest provide a unique opportunity to examine tree species – soil relationships in ecosystems that have developed without significant human disturbance. We characterized foliage, forest floor, and mineral soil nutrients associated with four canopy tree species (Douglas-fir (Pseudotsuga menziesii (Mirbel) Franco), western hemlock (Tsuga heterophylla (Raf.) Sarg.), western redcedar (Thuja plicata Donn ex D. Don), and bigleaf maple (Acer macrophyllum Pursh)) in eight old-growth forests of the Oregon Coast Range. The greatest forest floor accumulations of C, N, P, Ca, Mg, and K occurred under Douglas-fir, primarily due to greater forest floor mass. In mineral soil, western hemlock exhibited significantly lower Ca concentration and sum of cations (Ca + Mg + K) than bigleaf maple, with intermediate values for Douglas-fir and western redcedar. Bigleaf maple explained most species-based differences in foliar nutrients, displaying high concentrations of N, P, Ca, Mg, and K. Foliar P and N:P variations largely reflected soil P variation across sites. The four tree species that we examined exhibited a number of individualistic effects on soil nutrient levels that contribute to biogeochemical heterogeneity in these ecosystems. Where fire suppression and long-term succession favor dominance by highly shade-tolerant western hemlock, our results suggest a potential for declines in both soil Ca availability and soil biogeochemical heterogeneity in old-growth forests.

  2. Solving decontaminable flooring problems

    International Nuclear Information System (INIS)

    Anon.

    1989-01-01

    Pennsylvania Power and Light wanted to cover deteriorating concrete in unit 2 of its Susquehanna BWR with a smooth, durable, decontaminable coating. Traditionally, floors in the plant had been coated with epoxy paint, but many of these floors suffered delamination, and failed in three to five years. Painting with epoxy would also interrupt operations for as much as three days while the floor dried, yet critical instruments in some areas had to be monitored at least once per shift. In addition, conventional floor surface preparation produced dust and vibration around sensitive equipment. The solution was a dustless scabbling system for surface preparation, followed by the installation of a high-strength acrylic industrial floor known as Silakal. The work was carried out by Pentek. Silikal bonds to the underlying concrete, so that delamination of the floor will not occur even under severe traffic conditions. Another advantage of this type of flooring is that it cures in one hour, so floor resurfacing has only minimal impact on plant operations. (author)

  3. Testing Benefits Transfer of Forest Recreation Values over a 20-year time Horizon

    DEFF Research Database (Denmark)

    Zandersen, Marianne; Termansen, Mette; Jensen, F.S.

    2007-01-01

    We conduct a functional benefit transfer over 20 years of total willingness to pay based on car-borne forest recreation in 52 forests, using a mixed logit specification of a random utility model and geographic information systems to allow heterogeneous preferences across the population and for he......We conduct a functional benefit transfer over 20 years of total willingness to pay based on car-borne forest recreation in 52 forests, using a mixed logit specification of a random utility model and geographic information systems to allow heterogeneous preferences across the population...... and for heterogeneity over space. Results show that preferences for some forest attributes, such as species diversity and age, as well as transport mode have changed significantly over the period. Updating the transfer model with present total demand for recreation improves the error margins by an average of 282......%. Average errors of the best transfer model remain 25%....

  4. Introductory guide to floors and flooring

    CSIR Research Space (South Africa)

    Billingham, PA

    1977-01-01

    Full Text Available not make use of the warming and cooling effects of direct contact with the ground. Indeed the precautions that are necessary to protect such floors against damp and decay may actually reduce the comfort levels within a house. This is because there is a... with resultant discomfort and extra heating costs. Today, in South Africa, most modern homesareof singlestorey con- struction with aconcrete floor slab in direct contact with theground which once again makes its full contribution to the comfort and structural...

  5. Three-year monitoring study of radiocesium transfer and ambient dose rate in forest environments affected by the Fukushima Dai-ichi Nuclear Power Plant accident

    Science.gov (United States)

    Kato, Hiroaki; Onda, Yuichi; Loffredo, Nicolas; Kawamori, Ayumi; Hisadome, Keigo

    2015-04-01

    We investigated the transfer of canopy-intercepted radiocesium to the forest floor during 3 years (July 2011~) following the Fukushima Dai-ichi Nuclear Power Plant accident. The cesium-137 (Cs-137) contents of throughfall, stemflow, and litterfall were monitored in two coniferous stands (plantation of Japanese cedar) and a deciduous broad-leaved forest stand (Japanese oak with red pine). We also measured an ambient dose rate at different height in the forest by using a survey meter (TCS-172B, Hitachi-Aloka Medical, LTD.) and a portable Ge gamma-ray detector (Detective-DX-100T, Ortec, Ametek, Inc.). Furthermore, effects of forest decontamination on the reduction of ambient dose rate were assessed quantitatively. Total Cs-137 deposition flux from the canopy to forest floor for the mature cedar, young cedar, and the mixed broad-leaved stands were 157 kBq/m^2, 167 kBq/m^2, and 54 kBq/m^2, respectively. These values correspond to 36%, 39% and 12% of total atmospheric input after the accident. The ambient dose rate showed an exponential decrease with time for all the forest sites, however the decreasing trend differed depending on the forest type. These data suggested that an ambient dose rate in forest environment can be variable in spatially and temporally reflecting the transfer of radiocesium from canopy to forest floor. We presented the analysis results of the relationship between radiocesium deposition flux and ambient dose rate at the forest floor. In addition to that, we reported the effects of forest decontamination (e.g., tree felling, removal of organic materials, woodchip pavement) on the reduction of ambient dose rate in the forest environment.

  6. Carbon stocks of three secondary coniferous forests along an altitudinal gradient on Loess Plateau in inland China

    Science.gov (United States)

    Liu, Ning; Nan, Hongwei

    2018-01-01

    Natural forests in inland China are generally distributed in montane area and secondary due to a semi-arid climate and past anthropogenic disturbances. However, quantification of carbon (C) stock in these forests and the role of altitude in determining C storage and its partition among ecosystem components are unclear. We sampled 54 stands of three secondary coniferous forests (Larix principis-rupprechtii (LP) forest, Picea meyerii (PM) forest and Pinus tabulaeformis (PT) forest) on Loess Plateau in an altitudinal range of 1200-2700m a.s.l. C stocks of tree layer, shrub layer, herb layer, coarse wood debris, forest floor and soil were estimated. We found these forests had relatively high total C stocks. Driven by both higher vegetation and soil C stocks, total C stocks of LP and PM forests in the high altitudinal range were 375.0 and 368.4 t C ha-1 respectively, significantly higher than that of PT forest in the low altitudinal range (230.2 t C ha-1). In addition, understory shrubs accounted for about 20% of total biomass in PT forest. The proportions of vegetation to total C stock were similar among in the three forests (below 45%), so were the proportions of soil C stock (over 54%). Necromass C stocks were also similar among these forests, but their proportions to total C stock were significantly lower in LP and PM forests (1.4% and 1.6%) than in PT forest (3.0%). Across forest types, vegetation biomass and soil C stock simultaneously increased with increasing altitude, causing fairly unchanged C partitioning among ecosystem components along the altitudinal gradient. Soil C stock also increased with altitude in LP and PT forests. Forest floor necromass decreased with increasing altitude across the three forests. Our results suggest the important role of the altitudinal gradient in C sequestration and floor necromass of these three forests in terms of alleviated water conditions and in soil C storage of LP and PM forests in terms of temperature change. PMID

  7. Ion enrichment of snowmelt water by processes within a podzolic soil

    International Nuclear Information System (INIS)

    Hazlett, P.W.; Foster, N.W.; English, M.C.

    1992-01-01

    Ion concentrations in snowmelt runoff, forest-floor percolate and mineral-soil percolate collected in a tolerant hardwood forest at the Turkey Lakes Watershed, ON, were determined during the spring snowmelt of 1986. The results were examined to assess the modification of snowmelt water after contact with the forest soil. Concentrations of NO 3 - increased from 17 to 201 μmol c L -1 and SO 4 2- increased from 25 to 107 μmol c L -1 as meltwater passed through the organic layers and the upper mineral-soil horizons. Mineralization of organic N and S, and desorption of So 4 2- from the soil, provide sources of these ions for leaching during the snowmelt period. Ion-exchange reactions in the forest floor and upper mineral soil resulted in a decrease in H + and an increase in Ca 2+ concentration is solution. In the steep topography of this forested basin, the altered snowmelt solutions are rapidly transported downslope towards the aquatic system by lateral flow. Processes within the forest soil may therefore play an important role in determining the effects of snowmelt water on surface water chemistry in the spring

  8. Investigation of floor Nusselt number in floor heating system for insulated ceiling conditions

    International Nuclear Information System (INIS)

    Karadag, Refet; Teke, Ismail

    2007-01-01

    In this study, in a floor heated room, natural convection heat transfer over the floor is analysed numerically for different thermal conditions. An equation relevant to Nusselt number over the floor has been obtained by using the numerical data. Different equations are given in the literature. They consider the effect of floor Rayleigh number while neglecting the effect of wall and ceiling thermal conditions. Numerical data obtained in this study show that the Nusselt number over the floor depends on not only the floor Rayleigh number but also the wall Rayleigh number (for insulated ceiling conditions). The equations given in the literature are different from each other due to their not considering the effect of wall and ceiling Rayleigh numbers. This difference between the equations may be eliminated by obtaining an equation containing the effect of floor, wall and ceiling Rayleigh numbers. In this new approach, an equation relevant to the floor Nusselt number that depends on the floor and wall Rayleigh numbers has been obtained in the floor heating system for insulated ceiling conditions. The equation obtained in this study has been compared with the equations given in the literature. It has been seen that the equation obtained in this study matches the numerical values under more extensive thermal conditions than the equations given in the literature. The maximum deviation for the equations given in the literature is 35%, but in the current study, the maximum deviation has been found to be 10%. As a result, it is more convenient to use the equation found in the new approach as a function of Rayleigh number over the floor and wall for insulated ceiling conditions

  9. [Effect of pine plantations on soil arthropods in a high Andean forest].

    Science.gov (United States)

    León-Gamboa, Alba Lucía; Ramos, Carolina; García, Mary Ruth

    2010-09-01

    One of the most common problems in the Colombian mountains has been the replacement of native vegetation by pine plantations. Soil arthropods are a fundamental component of forest ecosystem, since they participate in the organic matter fragmentation, previous to decomposition. This role is more valuable in high altitude environments, where low temperatures limit the dynamics of biological processes, where the effects of pine plantations on soil arthropods are still not well-known. In a remnant of high-andean forest (Neusa - Colombia) and a pine plantation of about 50 years-old, it was evaluated the composition, richness and abundance of arthropods at surface (S), organic horizon (O) and mineral horizon (A) of soil, to establish the differences associated to the soil use transformation. It was used "Pitfall" sampling to register the movement of the epigeous fauna, and extraction by funnel Berlese for determining the fauna density from O and A horizons. The Shannon and Simpson indexes estimated the diversity at different places and horizons, and the trophic structure of the community was evaluated. Overall, there were collected 38 306 individuals from forest and 17 386 individuals from pine plantation, mainly distributed in Collembola (42.4%), Acari (27%), Diptera (17.6%) and Coleoptera (4.6%). The most important differences were given in the surface, where the mobilization in forest (86 individuals/day) almost triplicates the one in pine plantation (33 individuals/day). The differences in composition were given in Collembola, Araneae, Hemiptera, Homoptera and Hymenoptera. The dynamics of richness and abundance along the year had significant high values in the native forest than in the pine plantation. The general trophic structure was dominated by saprophagous (75%), followed by predators (14%) and phytophagous (9%), but in two layers of the pine plantation soil (S and O) this structural pattern was not given. Based on the results, it was concluded that pine

  10. Spatio-temporal variability of the deposited radioactive materials in forest environments after the Fukushima Daiichi NPP accident

    Science.gov (United States)

    Kato, H.; Onda, Y.; Komatsu, Y.; Yoda, H.

    2012-12-01

    Soil, vegetation and other ecological compartments are expected to be highly contaminated by the deposited radionuclides after the Fukushima Daiichi nuclear power plant (NPP) accident triggered by a magnitude 9.1 earthquake and the resulting tsunami on Marchi 11, 2011. Study site have been established in Yamakiya district, Kawamata Town, Fukushima prefecture, located about 35 km from Fukushima power plant, and designated as the evacuated zone. The total deposition of radioactive materials at the study site ranged from 0.02to >10 M Bq/m2 for Cs-137. The mature cedar, young cedar, and broad-leaf stands were selected as experimental site for the monitoring of spatio-temporal variability of the deposited radionuclides after the accidental release of radioactive materials. In order to measure the vertical distribution of radioactivity in forest, a tower with the same height of tree have been established at each experimental site. The measurement of radioactivity by using a portable Ge gamma-ray detector (Detective-DX-100, Ortec) and radionuclide analysis of leaf samples at different height revealed that a large proportion of radionuclides which deposited on forest were trapped by canopies of the cedar forests. In contrast, in the broad-leaf forest highest radioactivity was found at the forest floor. Furthermore, spatio-temporal variability of radioactivity at the forest floor indicated that huge amount of caesium still remains on the canopy of coniferous forest, and subsequently transfers to forest floor in association with throughfall, stemflow, and litter fall.

  11. A Synthesis of Sierran Forest Biomass Management Studies and Potential Effects on Water Quality

    Directory of Open Access Journals (Sweden)

    Peter J. Weisberg

    2010-09-01

    Full Text Available The Lake Tahoe basin, located along the California and Nevada border between the Carson and Sierra Nevada mountain ranges, represents a complex forested ecosystem consisting of numerous sub-watersheds and tributaries that discharge directly to Lake Tahoe. This synthesis focuses on historical and current nutrient pools and the effects of biomass management in watersheds of the basin relative to their potential impacts on nutrient (N, P related discharge water quality. An accumulating forest floor as a result of fire suppression has resulted in the build-up of large nutrient pools that now provide a “natural” source of long term nutrient availability to surface waters. As a consequence, stand and forest floor replacing wildfire may cause a large magnitude nutrient mobilization impact on runoff water quality. Hence, mechanical harvest and controlled burning have become popular management strategies. The most ecologically significant long-term effects of controlled fire appear to be the loss of C and N from the forest floor. Although the application of controlled fire may have some initial impact on overland/litter interflow nutrient loading, controlled burning in conjunction with mechanical harvest has the potential to improve runoff water quality by reducing N and P discharge and improving the overall health of forest ecosystems without the danger of a high intensity wildfire.

  12. Forest Structure Affects Soil Mercury Losses in the Presence and Absence of Wildfire.

    Science.gov (United States)

    Homann, Peter S; Darbyshire, Robyn L; Bormann, Bernard T; Morrissette, Brett A

    2015-11-03

    Soil is an important, dynamic component of regional and global mercury (Hg) cycles. This study evaluated how changes in forest soil Hg masses caused by atmospheric deposition and wildfire are affected by forest structure. Pre and postfire soil Hg measurements were made over two decades on replicate experimental units of three prefire forest structures (mature unthinned, mature thinned, clear-cut) in Douglas-fir dominated forest of southwestern Oregon. In the absence of wildfire, O-horizon Hg decreased by 60% during the 14 years after clearcutting, possibly the result of decreased atmospheric deposition due to the smaller-stature vegetative canopy; in contrast, no change was observed in mature unthinned and thinned forest. Wildfire decreased O-horizon Hg by >88% across all forest structures and decreased mineral-soil (0 to 66 mm depth) Hg by 50% in thinned forest and clear-cut. The wildfire-associated soil Hg loss was positively related to the amount of surface fine wood that burned during the fire, the proportion of area that burned at >700 °C, fire severity as indicated by tree mortality, and soil C loss. Loss of soil Hg due to the 200,000 ha wildfire was more than four times the annual atmospheric Hg emissions from human activities in Oregon.

  13. Cosmological and black hole apparent horizons

    CERN Document Server

    Faraoni, Valerio

    2015-01-01

    This book overviews the extensive literature on apparent cosmological and black hole horizons. In theoretical gravity, dynamical situations such as gravitational collapse, black hole evaporation, and black holes interacting with non-trivial environments, as well as the attempts to model gravitational waves occurring in highly dynamical astrophysical processes, require that the concept of event horizon be generalized. Inequivalent notions of horizon abound in the technical literature and are discussed in this manuscript. The book begins with a quick review of basic material in the first one and a half chapters, establishing a unified notation. Chapter 2 reminds the reader of the basic tools used in the analysis of horizons and reviews the various definitions of horizons appearing in the literature. Cosmological horizons are the playground in which one should take baby steps in understanding horizon physics. Chapter 3 analyzes cosmological horizons, their proposed thermodynamics, and several coordinate systems....

  14. Conformal Killing horizons and their thermodynamics

    Science.gov (United States)

    Nielsen, Alex B.; Shoom, Andrey A.

    2018-05-01

    Certain dynamical black hole solutions can be mapped to static spacetimes by conformal metric transformations. This mapping provides a physical link between the conformal Killing horizon of the dynamical black hole and the Killing horizon of the static spacetime. Using the Vaidya spacetime as an example, we show how this conformal relation can be used to derive thermodynamic properties of such dynamical black holes. Although these horizons are defined quasi-locally and can be located by local experiments, they are distinct from other popular notions of quasi-local horizons such as apparent horizons. Thus in the dynamical Vaidya spacetime describing constant accretion of null dust, the conformal Killing horizon, which is null by construction, is the natural horizon to describe the black hole.

  15. Spacetimes containing slowly evolving horizons

    International Nuclear Information System (INIS)

    Kavanagh, William; Booth, Ivan

    2006-01-01

    Slowly evolving horizons are trapping horizons that are ''almost'' isolated horizons. This paper reviews their definition and discusses several spacetimes containing such structures. These include certain Vaidya and Tolman-Bondi solutions as well as (perturbatively) tidally distorted black holes. Taking into account the mass scales and orders of magnitude that arise in these calculations, we conjecture that slowly evolving horizons are the norm rather than the exception in astrophysical processes that involve stellar-scale black holes

  16. Effect of pelvic floor rehabilitation technique in preventing the postpartum pelvic floor dysfunction

    Directory of Open Access Journals (Sweden)

    Shi-Qiong Li

    2017-04-01

    Full Text Available Objective: To explore the effect of pelvic floor rehabilitation technique in preventing the postpartum pelvic floor dysfunction and on the sexual life quality. Methods: A total of 286 puerpera with pelvic floor dysfunction who were admitted in our hospital from May, 2014 to May, 2015 42 d after delivery were included in the study, and randomized into the treatment group and the control group with 143 cases in each group. After guidance, the puerpera in the control group were given pelvic floor muscle training by themselves at home. On this basis, the puerpera in the treatment group were treated by the pelvic floor rehabilitation apparatus. The puerpera in the two groups were treated for 4 weeks. The pelvic floor function before treatment, 6 months and 1 year after delivery was detected. The color Doppler ultrasound apparatus was used to detect BSD, PUVA, UVJ-M, and BND 3 months after delivery. Results: BND, PUVA-R, PUVA-S, and UVJ-M 3 months after delivery in the treatment groups were significantly lower than those in the control group, while BSD-S was significantly higher than that in the control group. The improvement of type I and II muscle fiber fatigue (%, POP-Q degree, AP indication point (cm, and vaginal dynamic pressure (cmH2O was significantly superior to that in the control group. The comparison of pelvic floor muscle strength classification before treatment between the two groups was not statistically significant. After treatment, the pelvic floor muscle in the two groups was significantly strengthened, and the proportion of V grade patients was significantly increased when compared with before treatment. Conclusions: The postpartum early pelvic floor rehabilitation technique can effectively enhance the pelvic floor function, and prevent the postpartum pelvic floor dysfunction, with an accurate efficacy; therefore, it deserves to be widely recommended in the clinic.

  17. The dynamics of radionuclides in forest ecosystems

    International Nuclear Information System (INIS)

    Steiner, M.

    2003-01-01

    Foodstuff from forests, notably mushrooms and game, is still much higher contaminated than agricultural products. The dynamic transport and transfer processes relevant to radiocesium in forest ecosystems will be discussed. Fungi, notably their mycelia, and migration processes in forest soil play a key role. In the first phase after deposition, radiocesium is very mobile and infiltrates forest soil after direct deposition or weathering from the canopy, where it is quickly immobilized. Subsequently, it moves to deeper soil layers due to decomposition and mineralization of organic matter. This downward migration of radiocesium is almost completely compensated by an upward transport in fungal mycelia. Whereas the specific activities in the uppermost organic horizons decrease comparatively fast, the radiocesium content in deeper horizons may remain almost constant or even increase at the beginning. Fungi which specific to their species take up nutrients from different soil layers, reflect the different trends with time in their fruit bodies. Fungal mycelia play an important role not only in the vertical migration, but also in the horizontal transport of radiocesium in forest soil and the uptake by green plants. Most green plants of the forest ecosystem poor in nutrients take up nutrients and radiocesium through symbiotic fungi. The fruit bodies of Deer Truffle which grow below ground can exhibit activity levels one order of magnitude higher than those of edible mushrooms. At present there is a debate, whether highly contaminated Deer Truffle eaten by wild boar as a delicacy, can explain the trend of increasing contamination of wild boar which has been observed in the last few years in different regions of Germany. (orig.)

  18. The impact of clearcutting in boreal forests of Russia on soils: A review

    Science.gov (United States)

    Dymov, A. A.

    2017-07-01

    Data on the impact of tree logging in boreal forests of Russia on soils are systematized. Patterns of soil disturbances and transformation of microclimatic parameters within clearcutting areas are discussed. Changes in the conditions of pedogenesis in secondary forests are analyzed. It is suggested that the changes in forest soils upon reforestation of clearcutting areas might be considered as specific post-logging soil successions. Data characterizing changes in the thickness of litter horizons and in the intensity of elementary pedogenic processes, acidity, and the content of exchangeable bases in soils of clearcutting areas in the course of their natural reforestation are considered. The examples of human-disturbed (turbated) soil horizons and newly formed anthropogenic soils on clearcutting areas are described. It is suggested that the soils on mechanically disturbed parts of clearcutting areas can be separated as a specific group of detritus turbozems.

  19. Examples of plasma horizons

    International Nuclear Information System (INIS)

    Hanni, R.S.

    1975-01-01

    The concept of the plasma horizon, defined as the boundary of the region in which an infinitely thin plasma can be supported against Coulomb attraction by a magnetic field, shows that the argument of selective accretion does not rule out the existence of charged black holes embedded in a conducting plasma. A detailed account of the covariant definition of plasma horizon is given and some examples of plasma horizons are presented. 7 references

  20. Chemistry of burning the forest floor during the FROSTFIRE experimental burn, interior Alaska, 1999

    Science.gov (United States)

    Harden, J.W.; Neff, J.C.; Sandberg, D.V.; Turetsky, M.R.; Ottmar, R.; Gleixner, G.; Fries, T.L.; Manies, K.L.

    2004-01-01

    Wildfires represent one of the most common disturbances in boreal regions, and have the potential to reduce C, N, and Hg stocks in soils while contributing to atmospheric emissions. Organic soil layers of the forest floor were sampled before and after the FROSTFIRE experimental burn in interior Alaska, and were analyzed for bulk density, major and trace elements, and organic compounds. Concentrations of carbon, nutrients, and several major and trace elements were significantly altered by the burn. Emissions of C, N, and Hg, estimated from chemical mass balance equations using Fe, Al, and Si as stable constituents, indicated that 500 to 900 g C and up to 0 to 4 ?? 10-4 g Hg/M2 were lost from the site. Calculations of nitrogen loss range from -4 to +6 g/m2 but were highly variable (standard deviation 19), with some samples showing increased N concentrations post-burn potentially from canopy ash. Noncombustible major nutrients such as Ca and K also were inherited from canopy ash. Thermogravimetry indicates a loss of thermally labile C and increase of lignin-like C in char and ash relative to unburned counterparts. Overall, atmospheric impacts of boreal fires include large emissions of C, N and Hg that vary greatly as a function of severe fire weather and its access to deep organic layers rich in C, N, and Hg. In terrestrial systems, burning rearranges the vertical distribution of nutrients in fuels and soils, the proximity of nutrients and permafrost to surface biota, and the chemical composition of soil including its nutrient and organic constituents, all of which impact C cycling. Copyright 2004 by the American Geophysical Union.

  1. Mechanical mastication as a fuels treatment in southeastern forests

    Science.gov (United States)

    Jesse K. Kreye; J. Morgan Varner; Leda N. Kobziar

    2016-01-01

    Mastication is an increasingly common fuels treatment that redistributes ‘‘ladder’’ fuels to the forest floor to reduce vertical fuel continuity, crown fire potential, and fireline intensity. Despite its widespread adoption, it remains unclear how mastication impacts fuels, fire behavior, or plant communities  across Southeastern forest ecosystems. We evaluated these...

  2. Decontamination of floor surfaces

    International Nuclear Information System (INIS)

    Smirous, F.

    1983-01-01

    Requirements are presented put on the surfaces of floors of radiochemical workplaces. The mechanism is described of retaining the contaminant in the surface of the flooring, ways of reducing the hazards of floor surface contamination, decontamination techniques and used decontamination agents. (J.P.)

  3. Nitrogen dynamics across silvicultural canopy gaps in young forests of western Oregon

    Science.gov (United States)

    Thiel, A.L.; Perakis, S.S.

    2009-01-01

    Silvicultural canopy gaps are emerging as an alternative management tool to accelerate development of complex forest structure in young, even-aged forests of the Pacific Northwest. The effect of gap creation on available nitrogen (N) is of concern to managers because N is often a limiting nutrient in Pacific Northwest forests. We investigated patterns of N availability in the forest floor and upper mineral soil (0-10 cm) across 6-8-year-old silvicultural canopy gaps in three 50-70-year-old Douglas-fir forests spanning a wide range of soil N capital in the Coast Range and Cascade Mountains of western Oregon. We used extractable ammonium (NH4+) and nitrate (NO3-) pools, net N mineralization and nitrification rates, and NH4+ and NO3- ion exchange resin (IER) concentrations to quantify N availability along north-south transects run through the centers of 0.4 and 0.1 ha gaps. In addition, we measured several factors known to influence N availability, including litterfall, moisture, temperature, and decomposition rates. In general, gap-forest differences in N availability were more pronounced in the mineral soil than in the forest floor. Mineral soil extractable NH4+ and NO3- pools, net N mineralization and nitrification rates, and NH4+ and NO3- IER concentrations were all significantly elevated in gaps relative to adjacent forest, and in several cases exhibited significantly greater spatial variability in gaps than forest. Nitrogen availability along the edges of gaps more often resembled levels in the adjacent forest than in gap centers. For the majority of response variables, there were no significant differences between northern and southern transect positions, nor between 0.4 and 0.1 ha gaps. Forest floor and mineral soil gravimetric percent moisture and temperature showed few differences along transects, while litterfall carbon (C) inputs and litterfall C:N ratios in gaps were significantly lower than in the adjacent forest. Reciprocal transfer incubations of

  4. Nutrient limitation on ecosystem productivity and processes of mature and old-growth subtropical forests in China.

    Directory of Open Access Journals (Sweden)

    Enqing Hou

    Full Text Available Nitrogen (N is considered the dominant limiting nutrient in temperate regions, while phosphorus (P limitation frequently occurs in tropical regions, but in subtropical regions nutrient limitation is poorly understood. In this study, we investigated N and P contents and N:P ratios of foliage, forest floors, fine roots and mineral soils, and their relationships with community biomass, litterfall C, N and P productions, forest floor turnover rate, and microbial processes in eight mature and old-growth subtropical forests (stand age >80 yr at Dinghushan Biosphere Reserve, China. Average N:P ratios (mass based in foliage, litter (L layer and mixture of fermentation and humus (F/H layer, and fine roots were 28.3, 42.3, 32.0 and 32.7, respectively. These values are higher than the critical N:P ratios for P limitation proposed (16-20 for foliage, ca. 25 for forest floors. The markedly high N:P ratios were mainly attributed to the high N concentrations of these plant materials. Community biomass, litterfall C, N and P productions, forest floor turnover rate and microbial properties were more strongly related to measures of P than N and frequently negatively related to the N:P ratios, suggesting a significant role of P availability in determining ecosystem production and productivity and nutrient cycling at all the study sites except for one prescribed disturbed site where N availability may also be important. We propose that N enrichment is probably a significant driver of the potential P limitation in the study area. Low P parent material may also contribute to the potential P limitation. In general, our results provided strong evidence supporting a significant role for P availability, rather than N availability, in determining ecosystem primary productivity and ecosystem processes in subtropical forests of China.

  5. Drift and transmission FT-IR spectroscopy of forest soils: an approach to determine decomposition processes of forest litter

    International Nuclear Information System (INIS)

    Haberhauer, G.; Gerzabek, M.H.

    1999-06-01

    A method is described to characterize organic soil layers using Fourier transformed infrared spectroscopy. The applicability of FT-IR, either dispersive or transmission, to investigate decomposition processes of spruce litter in soil originating from three different forest sites in two climatic regions was studied. Spectral information of transmission and diffuse reflection FT-IR spectra was analyzed and compared. For data evaluation Kubelka Munk (KM) transformation was applied to the DRIFT spectra. Sample preparation for DRIFT is simpler and less time consuming in comparison to transmission FT-IR, which uses KBr pellets. A variety of bands characteristics of molecular structures and functional groups has been identified for these complex samples. Analysis of both transmission FT-IR and DRIFT, showed that the intensity of distinct bands is a measure of the decomposition of forest litter. Interferences due to water adsorption spectra were reduced by DRIFT measurement in comparison to transmission FT-IR spectroscopy. However, data analysis revealed that intensity changes of several bands of DRIFT and transmission FT-IR were significantly correlated with soil horizons. The application of regression models enables identification and differentiation of organic forest soil horizons and allows to determine the decomposition status of soil organic matter in distinct layers. On the basis of the data presented in this study, it may be concluded that FT-IR spectroscopy is a powerful tool for the investigation of decomposition dynamics in forest soils. (author)

  6. Stringy horizons

    Energy Technology Data Exchange (ETDEWEB)

    Giveon, Amit [Racah Institute of Physics, The Hebrew University,Jerusalem 91904 (Israel); Itzhaki, Nissan [Physics Department, Tel-Aviv University,Ramat-Aviv, 69978 (Israel); Kutasov, David [EFI and Department of Physics, University of Chicago,5640 S. Ellis Av., Chicago, IL 60637 (United States)

    2015-06-11

    We argue that classical (α{sup ′}) effects qualitatively modify the structure of Euclidean black hole horizons in string theory. While low energy modes experience the geometry familiar from general relativity, high energy ones see a rather different geometry, in which the Euclidean horizon can be penetrated by an amount that grows with the radial momentum of the probe. We discuss this in the exactly solvable SL(2,ℝ)/U(1) black hole, where it is a manifestation of the black hole/Sine-Liouville duality.

  7. Increasing soil temperature in a northern hardwood forest: effects on elemental dynamics and primary productivity

    Science.gov (United States)

    Patrick J. McHale; Myron J. Mitchell; Dudley J. Raynal; Francis P. Bowles

    1996-01-01

    To investigate the effects of elevated soil temperatures on a forest ecosystem, heating cables were buried at a depth of 5 cm within the forest floor of a northern hardwood forest at the Huntington Wildlife Forest (Adirondack Mountains, New York). Temperature was elevated 2.5, 5.0 and 7.5?C above ambient, during May - September in both 1993 and 1994. Various aspects of...

  8. Peat swamp forest of Thailand

    Energy Technology Data Exchange (ETDEWEB)

    Niyomdham, C.; Urapeepatanapong, C.; Pitayakajornwute, P. [Pikoolthong Royal Development Study Center, Bangkok (Thailand). Royal Forest Department

    1996-12-31

    Peat swamp forest in Thailand occurs extensively along coastal flatlands in the central and southern parts of the country and some small patches of topogenous peatland are present locally on several mountain tops of the northern region. Many have been deteriorated by recent extensive development programs. However, one large area, about 347.04 km{sup 2}, of ombrogenous peatland is still left intact in the Pru Toh Dang area where conservation activities are being strictly enforced under one of the Royal Initiative Projects. Pru Toh Dang peat consists of 5 metres of fibrous organic soil overlying pyritic marine clay. Despite an inhospitable, submerged and unstable forest floor, the floristic composition of the peat swamp forest is extremely complicated, consisting of 124 families and 470 species of which 109 families and 437 species of flowering plants, and 15 families and 33 species of ferns recorded between 1983-1989 by a team from the Forest Herbarium of the Royal Forest Department of Thailand. (orig.) (4 refs.)

  9. Soil-seed bank survival in forests of the southern United States

    Science.gov (United States)

    James S. Meadows; Frank T. Bonner; James D. Haywood

    2006-01-01

    We evaluated the longevity of seeds of 12 common woody species buried in fresh condition in the forest floor at three forest locations in Mississippi and Louisiana. Seed samples of each species were retrieved annually for 5 years from each location. Germination and tetrazolium chloride staining tests were conducted on the samples to determine germinative capacity. When...

  10. Hypholoma lateritium isolated from coarse woody debris, the forest floor, and mineral soil in a deciduous forest in New Hampshire

    Science.gov (United States)

    Therese A. Thompson; R. Greg Thorn; Kevin T. Smith

    2012-01-01

    Fungi in the Agaricomycetes (Basidiomycota) are the primary decomposers in temperate forests of dead wood on and in the forest soil. Through the use of isolation techniques selective for saprotrophic Agaricomycetes, a variety of wood decay fungi were isolated from a northern hardwood stand in the Bartlett Experimental Forest, New Hampshire, USA. In particular,

  11. Mechanisms controlling radionuclide mobility in forest soils

    International Nuclear Information System (INIS)

    Delvaux, B.; Kruyts, N.; Maes, E.; Agapkina, G.I.; Kliashtorin, A.; Bunzl, K.; Rafferty, B.

    1996-01-01

    Soil processes strongly influence the radionuclide mobility in soils. The mobility of radionuclides in forest soils is governed by several processes involving both abiotic and biotic factors. The sorption-desorption process chiefly governs the activity of radionuclides in the soil solution, hence thereby their mobility and biological availability. Radiocaesium exhibits a very low mobility in mineral soils. Both mobility and bioavailability however increase as the thickness of organic layers and their content in organic matter increases. Clay minerals of micaceous origin strongly act as slinks for radiocaesium in forest soils. The magnitude of cesium mineral fixation in topsoils is expected to be the highest in mineral soils of Eutric cambisol type, and, to a lesser extent, of type of Distric cambisol and Podzoluvisol. A low mobility of radiocaesium in the surface horizons of forest soils may also be partially explained by a biological mobilization: fungi absorb radiocaesium and transport it to upper layers, thereby contributing to constantly recycle the radioelement in the organic horizons. This mechanism is probably important in soils with thick organic layers (Podsol, Histosol, and, to a lesser extent, Distric cambisol and Podzoluvisol). Radionuclides can be associated with soluble organic anions in the soil solution of forest acid soils. Such associations are highly mobile: they are stable in conditions of poor biological activity (low temperatures, acid soil infertility, water excess, etc.). Their magnitude is expected to be the highest in thick acid organic layers (soils of type Podzol and Histosol)

  12. Using FIA data to inform United States forest carbon national-level accounting needs: 1990-2010

    Science.gov (United States)

    Linda S. Heath

    2013-01-01

    Forests are partially made up of carbon. Live vegetation, dead wood, forest floor, and soil all contain carbon. Through the process of photosynthesis, trees reduce carbon dioxide to carbohydrates and store the carbon in wood. By removing carbon dioxide from the atmosphere, forests mitigate climate change that may be brought on by increased atmospheric CO2...

  13. A canopy trimming experiment in Puerto Rico: the response of litter invertebrate communities to canopy loss and debris deposition in a tropical forest subject to hurricanes

    Science.gov (United States)

    Barbara A. Richardson; Michael J. Richardson; Grizelle Gonzalez; Aaron B. Shiels; Diane S. Srivastava

    2010-01-01

    Hurricanes cause canopy removal and deposition of pulses of litter to the forest floor. A Canopy Trimming Experiment (CTE) was designed to decouple these two factors, and to investigate the separate abiotic and biotic consequences of hurricane-type damage and monitor recovery processes. As part of this experiment, effects on forest floor invertebrate communities were...

  14. Flooring-systems and their interaction with usage of the floor

    DEFF Research Database (Denmark)

    Pedersen, Lars; Frier, Christian; Andersen, Lars Vabbersgaard

    2017-01-01

    Some flooring-system designs might be sensitive to their vibrational performance, as there might be the risk that serviceability-limit-state problems may be encountered. For evaluating the vibrational performance of the flooring-system at the design stage, decisions need to be made by the enginee...

  15. Black carbon content in a ponderosa pine forest of eastern Oregon with varying seasons and intervals of prescribed burns

    Science.gov (United States)

    Matosziuk, L.; Hatten, J. A.

    2016-12-01

    Soil carbon represents a significant component of the global carbon cycle. While fire-based disturbance of forest ecosystems acts as a carbon source, the increased temperatures can initiate molecular changes to forest biomass that convert fast cycling organic carbon into more stable forms such as black carbon (BC), a product of incomplete combustion that contains highly-condensed aromatic structures and very low hydrogen and oxygen content. Such forms of carbon can remain in the soil for hundred to thousands of years, effectively creating a long-term carbon sink. The goal of this project is to understand how specific characteristics of prescribed burns, specifically the season of burn and the interval between burns, affect the formation, structure, and retention of these slowly degrading forms of carbon in the soil. Both O-horizon (forest floor) and mineral soil (0-15 cm cores) samples were collected from a season and interval of burn study in Malheur National Forest. The study area is divided into six replicate units, each of which is sub-divided into four treatment areas and a control. Beginning in 1997, each treatment area was subjected to: i) spring burns at five-year intervals, ii) fall burns at five-year intervals, iii) spring burns at 15-year intervals, or iv) fall burns at 15-year intervals. The bulk density, pH, and C/N content of each soil were measured to assess the effect of the burn treatments on the soil. Additionally, the amount and molecular structure of BC in each sample was quantified using the distribution of specific molecular markers (benzene polycarboxylic acids or BPCAs) that are present in the soil following acid digestion.

  16. Metal partitioning and uptake in central Ontario forests

    International Nuclear Information System (INIS)

    Watmough, Shaun A.; Dillon, Peter J.; Epova, Ekaterina N.

    2005-01-01

    Evaluation of the potential environmental risk posed by metals depends to a great extent on modeling the fate and mobility of metals with soil-solution partitioning coefficients (K d ). However, the effect of biological cycling on metal partitioning is rarely considered in standard risk assessments. We determined soil-solution partitioning coefficients for 5 metals (Cd, Zn, Pb, Co and Ni) at 46 forested sites that border the Precambrian Shield in central Ontario, where soil pH aq varied from 3.9 to 8.1. Foliage from the dominant tree species and forest floor samples were also collected from each site to compare their metal levels with K d predictions. Analogous to other studies, log K d values for all metals were predicted by empirical linear regression with soil pH (r 2 = 0.66-0.72), demonstrating that metal partitioning between soil and soil solution can be reliably predicted for relatively unpolluted forest mineral soils by soil pH. In contrast, whereas the so-called bioavailable water-soluble metal fraction could be predicted from soil pH, metal concentrations in foliage and the forest floor at each site were not consistently related to pH. Risk assessment of metals should take into account the role of biota in metal cycling and partitioning in forests, particularly if metal bio-accumulation and chronic toxicity in the food chain, rather than metal mobility in soils, are of primary concern. - Metal cycling by plants should be considered in risk assessment studies

  17. Ecophysiology of a Mangrove Forest in Jobos Bay, Puerto Rico

    Science.gov (United States)

    ARIEL E. LUGO; ERNESTO MEDINA; ELVIRA CUEVAs; CINTR& #211; GILBERTO N; EDDIE N. LABOY NIEVES; SCH& #196; YARA EFFER NOVELLI

    2007-01-01

    We studied gas exchange, leaf dimensions, litter production, leaf and litterfall chemistry, nutrient flux to the forest floor, retranslocation rates, and nutrient use efficiency of mangroves in Jobos Bay, Puerto Rico. The fringe forest had a salinity gradient from the ocean (35‰) to a salt flat (100‰) and a basin (about 80‰). Red (Rhizophora mangle), white (...

  18. Nano-scale investigation of the association of microbial nitrogen residues with iron (hydr)oxides in a forest soil O-horizon

    Science.gov (United States)

    Keiluweit, Marco; Bougoure, Jeremy J.; Zeglin, Lydia H.; Myrold, David D.; Weber, Peter K.; Pett-Ridge, Jennifer; Kleber, Markus; Nico, Peter S.

    2012-10-01

    Amino sugars in fungal cell walls (such as chitin) represent an important source of nitrogen (N) in many forest soil ecosystems. Despite the importance of this material in soil nitrogen cycling, comparatively little is known about abiotic and biotic controls on and the timescale of its turnover. Part of the reason for this lack of information is the inaccessibility of these materials to classic bulk extraction methods. To address this issue, we used advanced visualization tools to examine transformation pathways of chitin-rich fungal cell wall residues as they interact with microorganisms, soil organic matter and mineral surfaces. Our goal was to document initial micro-scale dynamics of the incorporation of 13C- and 15N-labeled chitin into fungi-dominated microenvironments in O-horizons of old-growth forest soils. At the end of a 3-week incubation experiment, high-resolution secondary ion mass spectrometry imaging of hyphae-associated soil microstructures revealed a preferential association of 15N with Fe-rich particles. Synchrotron-based scanning transmission X-ray spectromicroscopy (STXM/NEXAFS) of the same samples showed that thin organic coatings on these soil microstructures are enriched in aliphatic C and amide N on Fe (hydr)oxides, suggesting a concentration of microbial lipids and proteins on these surfaces. A possible explanation for the results of our micro-scale investigation of chemical and spatial patterns is that amide N from chitinous fungal cell walls was assimilated by hyphae-associated bacteria, resynthesized into proteinaceous amide N, and subsequently concentrated onto Fe (hydr)oxide surfaces. If confirmed in other soil ecosystems, such rapid association of microbial N with hydroxylated Fe oxide surfaces may have important implications for mechanistic models of microbial cycling of C and N.

  19. Column leaching from a Danish forest soil amended with wood ashes: fate of major and trace elements

    DEFF Research Database (Denmark)

    Maresca, Alberto; Hansen, M.; Ingerslev, M.

    2018-01-01

    Application of wood ashes onto two Danish forest soil horizons (A- and O-horizons) was investigated through a series of column experiments for ash dosages of 3, 9 and 30 Mg ha−1. Developments in the composition of the percolating soil solutions were investigated both in a short- (below 0.5 m3 m−2...

  20. Entropy of black holes with multiple horizons

    Science.gov (United States)

    He, Yun; Ma, Meng-Sen; Zhao, Ren

    2018-05-01

    We examine the entropy of black holes in de Sitter space and black holes surrounded by quintessence. These black holes have multiple horizons, including at least the black hole event horizon and a horizon outside it (cosmological horizon for de Sitter black holes and "quintessence horizon" for the black holes surrounded by quintessence). Based on the consideration that the two horizons are not independent each other, we conjecture that the total entropy of these black holes should not be simply the sum of entropies of the two horizons, but should have an extra term coming from the correlations between the two horizons. Different from our previous works, in this paper we consider the cosmological constant as the variable and employ an effective method to derive the explicit form of the entropy. We also try to discuss the thermodynamic stabilities of these black holes according to the entropy and the effective temperature.

  1. Thinning effects on spotted owl prey and other forest-dwelling small mammals

    Science.gov (United States)

    Todd M. Willson; Eric D. Forsman

    2013-01-01

    Th inning has been promoted as a method for accelerating the development of late-seral habitat and improving the overall health and function of young forests in the Pacifi c Northwest. Population studies have shown early and positive responses to thinning by some small forest-floor mammals (primarily mice, terrestrial voles, and shrews). However, thinning reduces the...

  2. Supporting shop floor intelligence

    DEFF Research Database (Denmark)

    Carstensen, Peter; Schmidt, Kjeld; Wiil, Uffe Kock

    1999-01-01

    Many manufacturing enterprises are now trying to introduce various forms of flexible work organizations on the shop floor. However, existing computer-based production planning and control systems pose severe obstacles for autonomous working groups and other kinds of shop floor control to become r......-to-day production planning by supporting intelligent and responsible workers in their situated coordination activities on the shop floor....

  3. The role of fungi in the immobilisation and translocation of Cs137 in the organic horizons of a conifer forest in Ireland

    International Nuclear Information System (INIS)

    Dawson, David.

    1995-01-01

    This project investigates the size of the microbial and fungal biomass of the Of organic horizon of a Picea sitchensis forest soil. The immobilisation of Cs 137 within the microbial and fungal biomass is determined. The translocation of Cs 137 via fungal transport within the organic layers of a Pinus sylvestris forest is also investigated in a laboratory microcosm experiment and under field conditions. The microbial biomass was determined by fumigation-incubation using three soil biocides; chloroform, gamma irradiation and a selective fungicide. All biocides gave similar results for microbial biomass which was calculated from the pooled data to be 1.42 +-0.08 g C m -2 . The selective fungicide did not selectively kill the fungal biomass, it was therefore estimated to be 1.13 +- 0.06 g C m -2 . The fungal biomass was determined independently by the agar-film technique and found to be 10.63 +- 0.8 g C m -2 . The large difference in results is due to the methods used to identify the metabolically active fungal biomass. Chloroform and irradiation treatments yielded similar results for the quantity of Cs 137 immobilised within the fungal biomass. The selective fungicide did not selectively lyse the fungal biomass. The quantity of Cs 137 immobilised within the fungal biomass was estimated to be 8% of the Cs 137 deposition to the Of layer or 25 Bq g -1 C m -2 . The importation of Cs 137 into litterbags in the forest was observed as a cumulative effect over the period of study. The agar-film technique proved unsatisfactory in determining the relationship between Cs 137 importation and fungal growth. However, a significant (P 137 content of the O1 litterbags. A poor relationship was observed for Of litterbags. A large increase in Cs 137 activity on O1 and Of litter in the lab based study was observed although confounded by inadvertent contamination. (author)

  4. Variations in canopy and litter interception across a forest chronosequence in the southern Appalachian Mountains

    Science.gov (United States)

    Steven T. Brantley; Paul V. Bolstad; Stephanie H. Laseter; A. Christopher Oishi; Kimberly A. Novick; Chelcy F. Miniat

    2016-01-01

    Variations in evapotranspiration (ET) have been well documented across a variety of forest types and climates in recent decades; however, most of these data have focused on mature, secondgrowth stands. Here we present data on two important fluxes of water, canopy interception (Ic) and forest floor litter interception (Iff), across a chronosequence of forest age in the...

  5. Methods of soil resampling to monitor changes in the chemical concentrations of forest soils

    Science.gov (United States)

    Lawrence, Gregory B.; Fernandez, Ivan J.; Hazlett, Paul W.; Bailey, Scott W.; Ross, Donald S.; Villars, Thomas R.; Quintana, Angelica; Ouimet, Rock; McHale, Michael; Johnson, Chris E.; Briggs, Russell D.; Colter, Robert A.; Siemion, Jason; Bartlett, Olivia L.; Vargas, Olga; Antidormi, Michael; Koppers, Mary Margaret

    2016-01-01

    Recent soils research has shown that important chemical soil characteristics can change in less than a decade, often the result of broad environmental changes. Repeated sampling to monitor these changes in forest soils is a relatively new practice that is not well documented in the literature and has only recently been broadly embraced by the scientific community. The objective of this protocol is therefore to synthesize the latest information on methods of soil resampling in a format that can be used to design and implement a soil monitoring program. Successful monitoring of forest soils requires that a study unit be defined within an area of forested land that can be characterized with replicate sampling locations. A resampling interval of 5 years is recommended, but if monitoring is done to evaluate a specific environmental driver, the rate of change expected in that driver should be taken into consideration. Here, we show that the sampling of the profile can be done by horizon where boundaries can be clearly identified and horizons are sufficiently thick to remove soil without contamination from horizons above or below. Otherwise, sampling can be done by depth interval. Archiving of sample for future reanalysis is a key step in avoiding analytical bias and providing the opportunity for additional analyses as new questions arise.

  6. Methods of Soil Resampling to Monitor Changes in the Chemical Concentrations of Forest Soils.

    Science.gov (United States)

    Lawrence, Gregory B; Fernandez, Ivan J; Hazlett, Paul W; Bailey, Scott W; Ross, Donald S; Villars, Thomas R; Quintana, Angelica; Ouimet, Rock; McHale, Michael R; Johnson, Chris E; Briggs, Russell D; Colter, Robert A; Siemion, Jason; Bartlett, Olivia L; Vargas, Olga; Antidormi, Michael R; Koppers, Mary M

    2016-11-25

    Recent soils research has shown that important chemical soil characteristics can change in less than a decade, often the result of broad environmental changes. Repeated sampling to monitor these changes in forest soils is a relatively new practice that is not well documented in the literature and has only recently been broadly embraced by the scientific community. The objective of this protocol is therefore to synthesize the latest information on methods of soil resampling in a format that can be used to design and implement a soil monitoring program. Successful monitoring of forest soils requires that a study unit be defined within an area of forested land that can be characterized with replicate sampling locations. A resampling interval of 5 years is recommended, but if monitoring is done to evaluate a specific environmental driver, the rate of change expected in that driver should be taken into consideration. Here, we show that the sampling of the profile can be done by horizon where boundaries can be clearly identified and horizons are sufficiently thick to remove soil without contamination from horizons above or below. Otherwise, sampling can be done by depth interval. Archiving of sample for future reanalysis is a key step in avoiding analytical bias and providing the opportunity for additional analyses as new questions arise.

  7. Natural and artificial radionuclides in forest and bog soils: tracers for migration processes and soil development

    International Nuclear Information System (INIS)

    Schleich, N.; Degering, D.; Unterricker, S.

    2000-01-01

    Radionuclide distributions in undisturbed forest and bog soils, mostly situated in Saxony, Germany (Erzgebirge), were studied. Low concentrations of naturally-occurring U and Th decay series nuclides, including 210 Pb, and artificial radioisotopes ( 125 Sb, 134 Cs, 137 Cs, 241 Am) were determined using low-level γ-spectrometry. In addition, the activities of 238 Pu and 239,240 Pu were determined by radiochemical separation and α-spectrometry. 14 C and excess 210 Pb dating methods were used to date the sampled bog profiles. The different radionuclides show characteristic depth distributions in the forest and bog soil horizons, which were sub-sampled as thin slices. 125 Sb, 241 Am, 238 Pu and 239,240 Pu are strongly fixed in soil organic matter. In spruce forest soils, the influence of soil horizons with distinct properties dominates the vertical time-dependent distribution. In ombrotrophic bogs, the peak positions correlated with the year of maximum input of each nuclide. The Sb, Am and Pu ''time markers'' and the 14 C and 210 Pb dating results correspond very well. Although Cs seems to be relatively mobile in organic as well as mineral forest soil horizons, it is enriched in the organic material. In ombrotrophic bogs, Cs is very mobile in the peat deposit. In Sphagnum peat, Cs is translocated continuously towards the growing apices of the Sphagnum mosses, where it is accumulated. (orig.)

  8. Variable horizon in a peridynamic medium.

    Energy Technology Data Exchange (ETDEWEB)

    Silling, Stewart Andrew; Littlewood, David John; Seleson, Pablo

    2014-10-01

    A notion of material homogeneity is proposed for peridynamic bodies with vari- able horizon but constant bulk properties. A relation is derived that scales the force state according to the position-dependent horizon while keeping the bulk properties un- changed. Using this scaling relation, if the horizon depends on position, artifacts called ghost forces may arise in a body under homogeneous deformation. These artifacts de- pend on the second derivative of horizon and can be reduced by use of a modified equilibrium equation using a new quantity called the partial stress . Bodies with piece- wise constant horizon can be modeled without ghost forces by using a technique called a splice between the regions. As a limiting case of zero horizon, both partial stress and splice techniques can be used to achieve local-nonlocal coupling. Computational examples, including dynamic fracture in a one-dimensional model with local-nonlocal coupling, illustrate the methods.

  9. Black hole versus cosmological horizon entropy

    International Nuclear Information System (INIS)

    Davis, Tamara M; Davies, P C W; Lineweaver, Charles H

    2003-01-01

    The generalized second law of thermodynamics states that entropy always increases when all event horizons are attributed with an entropy proportional to their area. We test the generalized second law by investigating the change in entropy when dust, radiation and black holes cross a cosmological event horizon. We generalize for flat, open and closed Friedmann-Robertson-Walker universes by using numerical calculations to determine the cosmological horizon evolution. In most cases, the loss of entropy from within the cosmological horizon is more than balanced by an increase in cosmological event horizon entropy, maintaining the validity of the generalized second law of thermodynamics. However, an intriguing set of open universe models shows an apparent entropy decrease when black holes disappear over the cosmological event horizon. We anticipate that this apparent violation of the generalized second law will disappear when solutions are available for black holes embedded in arbitrary backgrounds

  10. Understory vegetation response to mechanical mastication and other fuels treatments in a ponderosa pine forest

    Science.gov (United States)

    Jeffrey M. Kane; J. Morgan Varner; Eric E. Knapp

    2010-01-01

    Questions: What influence does mechanical mastication and other fuel treatments have on: (1) canopy and forest floor response variables that influence understory plant development; (2) initial understory vegetation cover, diversity, and composition; and (3) shrub and non-native species density in a secondgrowth ponderosa pine forest....

  11. Soil properties and aspen development five years after compaction and forest floor removal

    Science.gov (United States)

    Douglas M. Stone; John D. Elioff

    1998-01-01

    Forest management activities that decrease soil porosity and remove organic matter have been associated with declines in site productivity. In the northern Lake States region, research is in progress in the aspen (Populus tremuloides Michx. and P. grandidentata Michx.) forest type to determine effects of soil compaction and organic...

  12. Neighborhoods of isolated horizons and their stationarity

    International Nuclear Information System (INIS)

    Lewandowski, Jerzy; Pawłowski, Tomasz

    2014-01-01

    A distinguished (invariant) Bondi-like coordinate system is defined in the spacetime neighborhood of a non-expanding horizon of arbitrary dimension via geometry invariants of the horizon. With its use, the radial expansion of a spacetime metric about the horizon is provided and the free data needed to specify it up to a given order are determined in spacetime dimension 4. For the case of an electro-vacuum horizon in four-dimensional spacetime, the necessary and sufficient conditions for the existence of a Killing field at its neighborhood are identified as differential conditions for the horizon data and data for the null surface transversal to the horizon. (paper)

  13. Hydrologic and forest management controls on DOC dynamics in the small watersheds of the H.J. Andrews Experimental Forest, OR

    Science.gov (United States)

    Lajtha, K.; Jones, J. A.

    2016-12-01

    Dissolved organic carbon (DOC) export from hillslopes to streams is an important component of the carbon cycle of a catchment and may be a critical source of energy for the aquatic food web in receiving waters. Using a long-term record of DOC and other dissolved nutrients and elements from paired watersheds from the H.J. Andrews Experimental Forest in Oregon, we explored hydrologic, climatic, and land-use controls on seasonal and inter-annual patterns of DOC flux in a seasonally dry ecosystem. Seasonal patterns of DOC flux demonstrated source limitations to DOC export, with DOC concentrations highest immediately following the first rains after a dry summer, and lowest after winter rains. In contrast, more geochemically-controlled elements showed simple dilution-concentration patterns with no seasonal hysteresis. Inter-annual patterns of DOC flux, however, did not provide evidence of source limitation, with DOC flux within a watershed tightly correlated to total discharge but not temperature. Among watersheds, forest harvest, even over 50 years ago, significantly reduced DOC flux but not fluxes of other elements including N; this response was linked to the loading of coarse woody debris to the forest floor. Chemical fingerprinting of DOC revealed that old-growth watersheds had higher fluxes of DOC characteristic of forest floor organic materials, likely delivered to streams through more surficial preferential flow pathways not subject to microbial alteration, respiration, or sorption losses. Taken together these results suggest that the biogeochemical composition of forested streams reflects both current hydrologic patterns and also processes that occurred many decades ago within the catchment.

  14. Quantifying the effect of fuel reduction treatments on fire behavior in boreal forests

    Science.gov (United States)

    B.W. Butler; R.D. Ottmar; T.S. Rupp; R. Jandt; E. Miller; K. Howard; R. Schmoll; S. Theisen; R.E. Vihnanek; D. Jimenez

    2013-01-01

    Mechanical (e.g., shearblading) and manual (e.g., thinning) fuel treatments have become the preferred strategy of many fire managers and agencies for reducing fire hazard in boreal forests. This study attempts to characterize the effectiveness of four fuel treatments through direct measurement of fire intensity and forest floor consumption during a single prescribed...

  15. Horizon Detection In The Visible Spectrum

    Science.gov (United States)

    2016-09-01

    processing units, to the software-based models in [7] and [8]. B. DEFINING THE HORIZON The horizon, according to the Oxford English Dictionary , is “the...Ed. Dordrecht, Holland: D. Reidel Publishing Company, 1978. [10] “horizon,” Oxford English Dictionary Online, 2016.[Online]. Available: http

  16. Electrodynamics of the event horizon

    International Nuclear Information System (INIS)

    Punsly, B.; Coroniti, F.V.

    1989-01-01

    This paper is an investigation of the electrodynamics of the event horizon of a Kerr black hole. It is demonstrated that the event horizon behaves quite generally as an asymptotic vacuum infinity for axisymmetric, charge-neutral, accreting electromagnetic sources. This is in contrast with the general notion that the event horizon can be treated as an imperfect conductive membrane with a surface impedance of 4π/c. The conductive-membrane model has been incorporated into the more sophisticated membrane paradigm of Thorne, Price, and Macdonald by supplementing the model with the full equations of general relativity. In certain situations (in particular those of astrophysical interest), the conductive-membrane interpretation forms the appropriate set of pictures and images in the membrane paradigm. In this paper we reevaluate the specific gedanken experiments that were originally used to motivate the paradigm. We find that great care must be exercised if the detailed interaction of a black hole's external gravitational field with a magnetized plasma is modeled by the electrodynamics of the conductive horizon membrane. For ingoing flows of plasma or electromagnetic waves (when the hole is passively accepting information), the interpretation of the horizon as a vacuum infinity is equivalent to an imperfect conductor with a surface impedance of 4π/c (the impedance of the vacuum). In situations when an imperfect conductor should radiate information (such as a Faraday wheel) the event horizon cannot, since it is an infinity. The event horizon does not behave quite generally as an imperfect conductor, but has electrodynamic properties unique to itself

  17. Mineralogy in the Waste Isolation Pilot Plant (WIPP) facility stratigraphic horizon

    International Nuclear Information System (INIS)

    Stein, C.L.

    1985-09-01

    Forty-six samples were selected for this study from two cores, one extending 50 ft up through the roof of the WIPP facility and the other penetrating 50 ft below the facility floor. These samples, selected from approximately every other foot of core length, represent the major lithologies present in the immediate vicinity of the WIPP facility horizon: ''clean'' halite, polyhalitic halite, argillaceous halite, and mixed polyhalitic-argillaceous halite. Samples were analyzed for non-NaCl mineralogy by determining weight percents of water- and EDTA-insoluble residues, which were then identified by x-ray diffraction. In general, WIPP halite contains at most 5 wt % non-NaCl residue. The major mineral constituents are quartz, magnesite, anhydrite, gypsum, polyhalite, and clays. Results of this study confirm that, in previous descriptions of WIPP core, trace mineral quantities have been visually overestimated by approximately an order of magnitude. 9 refs., 5 figs., 5 tabs

  18. 17 CFR 3.11 - Registration of floor brokers and floor traders.

    Science.gov (United States)

    2010-04-01

    ... 17 Commodity and Securities Exchanges 1 2010-04-01 2010-04-01 false Registration of floor brokers and floor traders. 3.11 Section 3.11 Commodity and Securities Exchanges COMMODITY FUTURES TRADING... a contract market or registered as a derivatives transaction execution facility by the Commission...

  19. Measuring and modeling carbon stock change estimates for US forests and uncertainties from apparent inter-annual variability

    Science.gov (United States)

    James E. Smith; Linda S. Heath

    2015-01-01

    Our approach is based on a collection of models that convert or augment the USDA Forest Inventory and Analysis program survey data to estimate all forest carbon component stocks, including live and standing dead tree aboveground and belowground biomass, forest floor (litter), down deadwood, and soil organic carbon, for each inventory plot. The data, which include...

  20. Forest nutrient and carbon pools at Walker Branch watershed: changes during a 21-year period

    Science.gov (United States)

    Carl C. Trettin; D.W. Johnson; D.E. Todd

    1999-01-01

    A 21-yr perspective on changes in nutrient and C pools on undisturbed upland forest sites is provided. Plots originally representing four cover types have been sampled three times. On each plot, forest biomass, forest floor, and soil, to a depth of 60 cm, were measured, sampled, and analyzed for Ca, Mg, C, N, and P. Exchangeable soil Ca and Mg have declined in most...

  1. Fiber-optical analog of the event horizon.

    Science.gov (United States)

    Philbin, Thomas G; Kuklewicz, Chris; Robertson, Scott; Hill, Stephen; König, Friedrich; Leonhardt, Ulf

    2008-03-07

    The physics at the event horizon resembles the behavior of waves in moving media. Horizons are formed where the local speed of the medium exceeds the wave velocity. We used ultrashort pulses in microstructured optical fibers to demonstrate the formation of an artificial event horizon in optics. We observed a classical optical effect: the blue-shifting of light at a white-hole horizon. We also showed by theoretical calculations that such a system is capable of probing the quantum effects of horizons, in particular Hawking radiation.

  2. When the douglas-firs were counted: The beginning of the Forest Survey

    Science.gov (United States)

    Ivan Doig

    1976-01-01

    The wonders which Phil Briegleb remembered from that stint of work - the dark green spill of forest from ridgeline to valley floor, the colonnade of giant boles crowding acre upon acre, the Depression-staving paycheck earned by sizing up this big timber - may have been grand, all right, but no more so than the language which spelled out the project. The Forest Survey...

  3. The partitioning of mercury in the solids components of forest soils and flooded forest soils in a hydroelectric reservoir, Quebec

    International Nuclear Information System (INIS)

    Dmytriw, R.P.

    1993-11-01

    Upon inundation, the soils in a hydroelection reservoir are subjected to several years of physical, biological and chemical changes as the transition from a terrestrial to an aquatic ecosystem is achieved. Changes in Eh, pH and microbial activity are believed to alter the metal binding capacity of solid substrates (organic matter, reactive Fe and Mn oxides, and clay minerals) within the soil profile, leading to remobilization of mercury associated with these phases. Four cores were collected along a transect from an unflooded forest soil to a pre-impoundment lake bottom sediment in the La-Grande-2 reservoir and watershed. The samples were sequentially extracted to determine the distribution of mercury between three operationally defined solid compartments: organic carbon, reactive Fe and Mn oxides/hydroxides, and the solid clay residue. Results indicate that up to 80% of the mercury in the O-horizon in forest soils and flooded forest soils, and up to 85% of the mercury in the lake sediments is bound to NaOH extractable organic carbon fractions. In the B-horizon podzol where organic content is low, 40-60% of the total mercury was found to be associated with reactive Fe minerals. In contrast, the flooded soil contains very little reactive Fe at any depth and the associated mercury concentrations are low. It is proposed that, upon inundation, oxide minerals are reduced and Hg released to the pore waters where it is immediately bound to an available substrate. Analyses of the residues suggests that there is an enrichment of mercury in the residual fraction immediately above the B-horizon of a flooded soil while the sulfide mineralization appears to play a role in sequestering mercury in lake sediments. 14 refs., 22 figs., 3 tabs

  4. Land use change effects on forest carbon cycling throughout the southern United States

    Science.gov (United States)

    Peter B. Woodbury; Linda S. Heath; James E. Smith

    2006-01-01

    We modeled the effects of afforestation and deforestation on carbon cycling in forest floor and soil from 1900 to 2050 throughout 13 states in the southern United States. The model uses historical data on gross (two-way) transitions between forest, pasture, plowed agriculture, and urban lands along with equations describing changes in carbon over many decades for each...

  5. Using random forest for the risk assessment of coal-floor water inrush in Panjiayao Coal Mine, northern China

    Science.gov (United States)

    Zhao, Dekang; Wu, Qiang; Cui, Fangpeng; Xu, Hua; Zeng, Yifan; Cao, Yufei; Du, Yuanze

    2018-04-01

    Coal-floor water-inrush incidents account for a large proportion of coal mine disasters in northern China, and accurate risk assessment is crucial for safe coal production. A novel and promising assessment model for water inrush is proposed based on random forest (RF), which is a powerful intelligent machine-learning algorithm. RF has considerable advantages, including high classification accuracy and the capability to evaluate the importance of variables; in particularly, it is robust in dealing with the complicated and non-linear problems inherent in risk assessment. In this study, the proposed model is applied to Panjiayao Coal Mine, northern China. Eight factors were selected as evaluation indices according to systematic analysis of the geological conditions and a field survey of the study area. Risk assessment maps were generated based on RF, and the probabilistic neural network (PNN) model was also used for risk assessment as a comparison. The results demonstrate that the two methods are consistent in the risk assessment of water inrush at the mine, and RF shows a better performance compared to PNN with an overall accuracy higher by 6.67%. It is concluded that RF is more practicable to assess the water-inrush risk than PNN. The presented method will be helpful in avoiding water inrush and also can be extended to various engineering applications.

  6. Optimal investment horizons

    Science.gov (United States)

    Simonsen, I.; Jensen, M. H.; Johansen, A.

    2002-06-01

    In stochastic finance, one traditionally considers the return as a competitive measure of an asset, i.e., the profit generated by that asset after some fixed time span Δt, say one week or one year. This measures how well (or how bad) the asset performs over that given period of time. It has been established that the distribution of returns exhibits ``fat tails'' indicating that large returns occur more frequently than what is expected from standard Gaussian stochastic processes [1-3]. Instead of estimating this ``fat tail'' distribution of returns, we propose here an alternative approach, which is outlined by addressing the following question: What is the smallest time interval needed for an asset to cross a fixed return level of say 10%? For a particular asset, we refer to this time as the investment horizon and the corresponding distribution as the investment horizon distribution. This latter distribution complements that of returns and provides new and possibly crucial information for portfolio design and risk-management, as well as for pricing of more exotic options. By considering historical financial data, exemplified by the Dow Jones Industrial Average, we obtain a novel set of probability distributions for the investment horizons which can be used to estimate the optimal investment horizon for a stock or a future contract.

  7. Climatic impacts on managed forests: projecting the future from the past

    OpenAIRE

    Martel, Simon; Picart, Delphine; Bosc, Alexandre; Moisy, Christophe; Lafont, Sebastien; Loustau, Denis; Picard, Olivier; Breda, Nathalie

    2015-01-01

    Forests are one of the most vulnerable ecosystem under the coming climate changeand a growing concern arise about their capacity to maintain ecosystem services suchas production of timber, fiber and energy, climate and hydrological regulations, or soil and biodiversity protection. Climate effects are significant not only at a short timescale, but also on the temporal horizon of a forest life cycle, e.g. through continuous shifts in atmospheric CO2 concentration, air temperature and precipitat...

  8. Motivations to leave coarse woody debris in private forests

    DEFF Research Database (Denmark)

    Boon, Tove Enggrob; Meilby, Henrik; Andersen, Anne Sofie Kirkegaard

    2014-01-01

    costs and benefits incurred? Based on the theory of planned behaviour, the aim of this study is to investigate forest owners’ motivation to integrate nature concerns in forest management. As criteria for choosing a relevant case, we looked for a measure that has a potential to significantly improve...... biodiversity, has political attention, is tangible, constitutes something any forest owner can do even on a small area of land, involves potential trade-offs with other management goals, and, preferably something that most forest owners and their personal network would have an opinion about.......Based on these criteria, we selected the case of leaving coarse woody debris on the forest floor. A survey questionnaire was designed and sent to 1434 private forest owners in Denmark, 686 of whom answered. The presentation includes the first results of the analysis....

  9. VMware horizon view essentials

    CERN Document Server

    von Oven, Peter

    2014-01-01

    If you are a desktop administrator or an end user of a computing project team looking to speed up to the latest VMware Horizon View solution, then this book is perfect for you. It is your ideal companion to deploy a solution to centrally manage and virtualize your desktop estate using Horizon View 6.0.

  10. Floor cooler for floor trough of a nuclear reactor

    International Nuclear Information System (INIS)

    Friedrich, H.J.

    1985-01-01

    Cooling pipes are situated below the floor trough of a BWR, which are connected to the annular distribution or collection pipes. The distribution and collection pipes are connected by parallel hairpin pipes with involute shape to the centre of the floor trough. These hairpin pipes are situated in a lower plane than the annular distribution pipe to the centre and in a higher plane from the centre to the outer annular collector pipe. (orig./HP) [de

  11. An ecosystem carbon database for Canadian forests

    Energy Technology Data Exchange (ETDEWEB)

    Shaw, C.H.; Bhatti, J.S.; Sabourin, K.J.

    2005-07-01

    The forest ecosystem carbon database (FECD) is a compilation of data from more than 700 plots from different forest ecosystems in Canada. It includes more than 60 variables for site, stand and soil characteristics. It is intended for large-scale modelers and analysts working with the carbon budget and dynamics of forest ecosystems, particularly those interested in the response of forest carbon stocks and fluxes to changes in climate and site characteristics. The database includes totals for organic and mineral soil horizons for each plot along with total soil carbon content, tree biomass carbon content by component and total ecosystem carbon content. It is complete for site description information, soil chemistry, stand-level estimates of live tree biomass and carbon components and their totals. Soil carbon content by horizon was also included. The compilation targeted data collected at single points in space, where above ground and below ground carbon levels were measured simultaneously. It was noted that one of the important information gaps lies in the fact that no data was available for the natural disturbance or management histories of the stands where the plots were located. Estimates did not include detrital carbon or root biomass, which can influence the estimates for total ecosystem carbon in some forest types. The preliminary analysis reveals that ecozones can be grouped according to low and high average total biomass carbon content. The groups correlate to ecozones with low and high average total ecosystem carbon. Mineral soil carbon within each group contributes the highest proportion of carbon to the average total ecosystem carbon. It is correlated with a gradient in ecozone climate from cold and dry to warm and wet. 42 refs., 13 tabs., 16 figs.

  12. Radionuclides in a deciduous forest surrounding a shallow-land-burial site in the eastern United States

    International Nuclear Information System (INIS)

    Rickard, W.H.; Kirby, L.J.; McShane, M.C.

    1981-06-01

    The objective of this study was to determine if radioactive materials buried in trenches at the Maxey Flats burial ground in eastern Kentucky have migrated into the surrounding oak-hickory forest. Forest floor litter, minearl soil, and tree leaves were sampled and the radionuclide content measured

  13. Dynamics of Mixed Dipterocarps Forests in Wanariset Semboja, East Kalimantan after Three Times of Forest Fires within the Periods of 1980-2003

    Directory of Open Access Journals (Sweden)

    HERWINT SIMBOLON

    2005-04-01

    Full Text Available A plot of 150x700 m2 was established in a mixed dipterocarps of Wanariset Semboja, East Kalimantan during the periods of 1979-1981. The forest was dominated by Eusideroxylon zwageri (Lauraceae, Dipterocarpus cornutus (Dipterocarpaceae, Pholidocarpus majadum (Arecaceae, and Diospyros borneensis (Ebenaceae. Since the plot establishment, the forests then had experienced three times of forest fires, those were in 1982-1983, 1994-1995 and 1997-1998. The present paper reports the results of re-measurement of some 150x110 m2 parts of the plot in August 2003, about 23 years after plot establishment. Micro topographically, the studied plot was relatively undulating in higher parts and relatively flat in the lower parts of the plot, while the differences between lowest sub-plot and higher sub-plot of the re-measured plot was 26 m. Forest floor of the lower parts of the plot were humid to wet during rainy season and still humid during dry season. Almost all of the trees within lower parts of the plot were escaped from these three times of forest fires; hence these sub-plots were dominated by the trees of primary species that enumerated in 1980. Those sub-plots in the higher parts were burnt during the past forest fires indicated by the charcoal of standing trees and remaining felling logs in the forest floor. These burnt sub-plots were dominated by pioneer or secondary tree species, such as: Mallotus spp., Macaranga spp., Ficus spp. and Vernonia arborea. Local distribution of some indicator species (such as primary tree species: Pholidocarpus majadum, Diospyros spp., Eusideroxylon zwageri and species of Dipterocarpaceae; pioneer or secondary tree species Vernonia arborea, Macaranga spp., Mallotus spp., Ficus uncinulata, Piper aduncum, Peronema canescens within the plot were figured. Mortality, recruitment and growth rate during the period of 1980-2003 were also discussed.

  14. Entropy of black holes with multiple horizons

    Directory of Open Access Journals (Sweden)

    Yun He

    2018-05-01

    Full Text Available We examine the entropy of black holes in de Sitter space and black holes surrounded by quintessence. These black holes have multiple horizons, including at least the black hole event horizon and a horizon outside it (cosmological horizon for de Sitter black holes and “quintessence horizon” for the black holes surrounded by quintessence. Based on the consideration that the two horizons are not independent each other, we conjecture that the total entropy of these black holes should not be simply the sum of entropies of the two horizons, but should have an extra term coming from the correlations between the two horizons. Different from our previous works, in this paper we consider the cosmological constant as the variable and employ an effective method to derive the explicit form of the entropy. We also try to discuss the thermodynamic stabilities of these black holes according to the entropy and the effective temperature.

  15. Spatial and temporal small-scale variability of nitrogen mobilization in a forest ecosystem with high N deposition in NW-Germany.

    Science.gov (United States)

    Lorz, Carsten; Eissner, Christel; Lethmate, Jürgen; Schneider, Birgit

    2010-02-01

    For conifer stands in NW-Germany with high DIN load (23-35 kg N ha(-1) a(-1)) and a long history of nitrogen export the risk of N mobilization were investigated. Ammonium is the most mobilized N species, pointing towards either conditions not favoring nitrification or, more likely - under the dominant aerobic conditions - a very high amount of ammonium in the forest floor. Independence of net nitrification and net ammonification from each other indicates the existence of two separate systems. The nitrifying system depends very much on biotic conditions - as a function of energy and moisture - and seems not to be directly related to N deposition. In contrast, for the ammonification system (Oe horizon) a correlation with the sum of ammonium deposition three months prior to sampling was found. However, the role of disturbance, i.e. nitrogen export, during the last centuries and the role of recovery of the N balance during the last 150 years is still not clear. Copyright (c) 2009 Elsevier Ltd. All rights reserved.

  16. [Functional aspects of pelvic floor surgery].

    Science.gov (United States)

    Wagenlehner, F M E; Gunnemann, A; Liedl, B; Weidner, W

    2009-11-01

    Pelvic floor dysfunctions are frequently seen in females. The human pelvic floor is a complex structure and heavily stressed throughout female life. Recent findings in the functional anatomy of the pelvic floor have led to a much better understand-ing, on the basis of which enormous improvements in the therapeutic options have arisen. The pelvic floor activity is regulated by three main muscular forces that are responsible for vaginal tension and suspension of the pelvic floor -organs, bladder and rectum. For different reasons laxity in the vagina or its supporting ligaments as a result of altered connective tissue can distort this functional anatomy. A variety of symptoms can derive from these pelvic floor dysfunctions, such as urinary urge and stress incontinence, abnormal bladder emptying, faecal incontinence, obstructive bowel disease syndrome and pelvic pain. Pelvic floor reconstruction is nowadays driven by the concept that in the case of pelvic floor symptoms restoration of the anatomy will translate into restoration of the physiology and ultimately improve the patients' symptoms. The exact surgical reconstruction of the anatomy is there-fore almost exclusively focused on the restoration of the lax pelvic floor ligaments. An exact identification of the anatomic lesions preoperatively is eminently necessary, to allow for an exact anatomic reconstruction with respect to the muscular forces of the pelvic floor. Georg Thieme Verlag Stuttgart * New York.

  17. Pelvic floor physical therapy in urogynecologic disorders.

    Science.gov (United States)

    Kotarinos, Rhonda K

    2003-08-01

    Physical therapists are uniquely qualified to treat pelvic floor dysfunction with conservative management techniques. Techniques associated with incontinence and support functions of the pelvic floor include bladder training and pelvic floor rehabilitation: pelvic floor exercises, biofeedback therapy, and pelvic floor electrical stimulation. Pain associated with mechanical pelvic floor dysfunction can be treated by physical therapists utilizing various manual techniques and modalities. Research documents that conservative management is effective in treating many conditions associated with pelvic floor dysfunction. Research should be conducted to determine if addressing diastasis recti and contracture of the pelvic floor musculature should be a component of the standard physical therapy protocol.

  18. Safety aspects related to the radioactively contaminated forest areas in Belarus

    International Nuclear Information System (INIS)

    SULLIVAN, T.; GIBBS, B.; ANDERSSON, K.G.; ROED, J.; RYMKEVICH, V.; BREKKE, D.

    1998-01-01

    Doses currently received in Belarus through various pathways related to the contamination of forests are evaluated through calculations. A major pathway is, as expected, generally found to be the external radiation from a contaminated forest floor. Also other pathways may in some cases be highly significant. Generally, it is found that the dose contributions to people spending time in the contaminated forest or consuming forest products are highest, whereas for instance doses received from domestic use of fire-wood are found to be negligible. Recommendations for storage of waste from combustion plants fired with radioactive forest material are also given, together with an estimate of the specific activity of the waste to be disposed of

  19. Macro-particle charcoal C content following prescribed burning in a mixed-conifer forest, Sierra Nevada, California.

    Science.gov (United States)

    Wiechmann, Morgan L; Hurteau, Matthew D; Kaye, Jason P; Miesel, Jessica R

    2015-01-01

    Fire suppression and changing climate have resulted in increased large wildfire frequency and severity in the western United States, causing carbon cycle impacts. Forest thinning and prescribed burning reduce high-severity fire risk, but require removal of biomass and emissions of carbon from burning. During each fire a fraction of the burning vegetation and soil organic matter is converted into charcoal, a relatively stable carbon form. We sought to quantify the effects of pre-fire fuel load and type on charcoal carbon produced by biomass combusted in a prescribed burn under different thinning treatments and to identify more easily measured predictors of charcoal carbon mass in a historically frequent-fire mixed-conifer forest. We hypothesized that charcoal carbon produced from coarse woody debris (CWD) during prescribed burning would be greater than that produced from fine woody debris (FWD). We visually quantified post-treatment charcoal carbon content in the O-horizon and the A-horizon beneath CWD (> 30 cm diameter) and up to 60 cm from CWD that was present prior to treatment. We found no difference in the size of charcoal carbon pools from CWD (treatment means ranged from 0.3-2.0 g m-2 of A-horizon and 0.0-1.7 g m-2 of O-horizon charcoal) and FWD (treatment means ranged from 0.2-1.7 g m-2 of A-horizon and 0.0-1.5 g m-2 of O-horizon charcoal). We also compared treatments and found that the burn-only, understory-thin and burn, and overstory-thin and burn treatments had significantly more charcoal carbon than the control. Charcoal carbon represented 0.29% of total ecosystem carbon. We found that char mass on CWD was an important predictor of charcoal carbon mass, but only explained 18-35% of the variation. Our results help improve our understanding of the effects forest restoration treatments have on ecosystem carbon by providing additional information about charcoal carbon content.

  20. Cartan invariants and event horizon detection

    Science.gov (United States)

    Brooks, D.; Chavy-Waddy, P. C.; Coley, A. A.; Forget, A.; Gregoris, D.; MacCallum, M. A. H.; McNutt, D. D.

    2018-04-01

    We show that it is possible to locate the event horizon of a black hole (in arbitrary dimensions) by the zeros of certain Cartan invariants. This approach accounts for the recent results on the detection of stationary horizons using scalar polynomial curvature invariants, and improves upon them since the proposed method is computationally less expensive. As an application, we produce Cartan invariants that locate the event horizons for various exact four-dimensional and five-dimensional stationary, asymptotically flat (or (anti) de Sitter), black hole solutions and compare the Cartan invariants with the corresponding scalar curvature invariants that detect the event horizon.

  1. School Flooring Factors

    Science.gov (United States)

    McGrath, John

    2012-01-01

    With all of the hype that green building is receiving throughout the school facility-management industry, it's easy to overlook some elements that may not be right in front of a building manager's nose. It is helpful to examine the role floor covering plays in a green building project. Flooring is one of the most significant and important systems…

  2. Does water stress, nutrient limitation, or H-toxicity explain the differential stature among Heath Forest types in Central Kalimantan, Indonesia?

    NARCIS (Netherlands)

    Vernimmen, R.R.E.; Bruijnzeel, L.A.; Proctor, J.; Verhoef, H.A.; Klomp, N.

    2013-01-01

    To investigate the causes of the reduced stature of heath forest compared to lowland evergreen rain forest (LERF), the quantity and quality of small litterfall (LF), the standing crop of litter on the forest floor (LSC), and the annual rates of litter decay were determined over a period of 12 months

  3. Generalized Robertson-Walker Space-Time Admitting Evolving Null Horizons Related to a Black Hole Event Horizon.

    Science.gov (United States)

    Duggal, K L

    2016-01-01

    A new technique is used to study a family of time-dependent null horizons, called " Evolving Null Horizons " (ENHs), of generalized Robertson-Walker (GRW) space-time [Formula: see text] such that the metric [Formula: see text] satisfies a kinematic condition. This work is different from our early papers on the same issue where we used (1 + n )-splitting space-time but only some special subcases of GRW space-time have this formalism. Also, in contrast to previous work, we have proved that each member of ENHs is totally umbilical in [Formula: see text]. Finally, we show that there exists an ENH which is always a null horizon evolving into a black hole event horizon and suggest some open problems.

  4. Litter input controls on soil carbon in a temperate deciduous forest

    DEFF Research Database (Denmark)

    Bowden, Richard D.; Deem, Lauren; Plante, Alain F.

    2014-01-01

    Above- and belowground litter inputs in a temperate deciduous forest were altered for 20 yr to determine the importance of leaves and roots on soil C and soil organic matter (SOM) quantity and quality. Carbon and SOM quantity and quality were measured in the O horizon and mineral soil to 50 cm...... soil C, but decreases in litter inputs resulted in rapid soil C declines. Root litter may ultimately provide more stable sources of soil C. Management activities or environmental alterations that decrease litter inputs in mature forests can lower soil C content; however, increases in forest...

  5. Long-term dynamics of heavy metals in the upper horizons of soils in the region of a copper smelter impacts during the period of reduced emission

    Science.gov (United States)

    Vorobeichik, E. L.; Kaigorodova, S. Yu.

    2017-08-01

    The 23-year-long dynamics of actual acidity (pHwater) and acid-soluble heavy metals (Cu, Pb, Cd, Zn) in the forest litter and humus horizon of soils in spruce-fir forests were studied in the area subjected to the long-term (since 1940) pollution with atmospheric emissions from the Middle Ural Copper Smelter (Revda, Sverdlovsk oblast). For this purpose, 25 permanent sample plots were established on lower slopes at different distances from the enterprise (30, 7, 4, 2, and 1 km; 5 plots at each distance) in 1989. The emissions from the smelter have decreased since the early 1990s. In 2012, the emissions of sulfur dioxide and dust decreased by 100 and 40 times, respectively, as compared with the emissions in 1980. Samples of litter and humus horizons were collected on permanent plots in 1989, 1999, and 2012. The results indicate that the pH of the litter and humus horizons restored to the background level 10 and 23 years after the beginning of the reduction in emissions, respectively. However, these characteristics in the impact zone still somewhat differ from those in the background area. In 2012, the content of Cu in the litter decreased compared to 1989 on all the plots; the content of Cu in the humus horizon decreased only in the close vicinity of the smelter. The contents of other metals in the litter and humus horizons remain constant or increased (probably because of the pH-dependent decrease in migration capacity). The absence of pronounced removal of metals from soils results in the retention of high contamination risk and the conservation of the suppressed state of biota within the impact zone.

  6. Transparc

    DEFF Research Database (Denmark)

    Callesen, Ingeborg; Vesterdal, Lars

    2017-01-01

    The TransparC forest soil carbon simulation model aims to demonstrate the slow, but yet dynamic character of the forest soil C balance to researchers, students and policy makers. The forest soil carbon simulator lumps new and old organic matter into one pool for each of six different depth segments....... These can be fixed depth segments or soil horizons. The excel spreadsheet runs for 40 years and calculates annual changes in the soil carbon sink in t C ha-1. Inputs are soil depth segments (cm), initial soil carbon content (% C), annual aboveground litter fall (g m-2), root litter distribution...... (% of aboveground litter fall) and turnover rates (k, year-1) for each depth segment. Two important pedological processes in mineral forest soils, bioturbation by macrofauna (earthworms) and podzolisation are included, allowing transfer of SOC between the forest floor and mineral soil layers. Four common forested...

  7. A Canadian upland forest soil profile and carbon stocks database.

    Science.gov (United States)

    Shaw, Cindy; Hilger, Arlene; Filiatrault, Michelle; Kurz, Werner

    2018-04-01

    "A Canadian upland forest soil profile and carbon stocks database" was compiled in phases over a period of 10 years to address various questions related to modeling upland forest soil carbon in a national forest carbon accounting model. For 3,253 pedons, the SITES table contains estimates for soil organic carbon stocks (Mg/ha) in organic horizons and mineral horizons to a 100-cm depth, soil taxonomy, leading tree species, mean annual temperature, annual precipitation, province or territory, terrestrial ecozone, and latitude and longitude, with an assessment of the quality of information about location. The PROFILES table contains profile data (16,167 records by horizon) used to estimate the carbon stocks that appear in the SITES table, plus additional soil chemical and physical data, where provided by the data source. The exceptions to this are estimates for soil carbon stocks based on Canadian National Forest Inventory data (NFI [2006] in REFERENCES table), where data were collected by depth increment rather than horizon and, therefore, total soil carbon stocks were calculated separately before being entered into the SITES table. Data in the PROFILES table include the carbon stock estimate for each horizon (corrected for coarse fragment content), and the data used to calculate the carbon stock estimate, such as horizon thickness, bulk density, and percent organic carbon. The PROFILES table also contains data, when reported by the source, for percent carbonate carbon, pH, percent total nitrogen, particle size distribution (percent sand, silt, clay), texture class, exchangeable cations, cation and total exchange capacity, and percent Fe and Al. An additional table provides references (REFERENCES table) for the source data. Earlier versions of the database were used to develop national soil carbon modeling categories based on differences in carbon stocks linked to soil taxonomy and to examine the potential of using soil taxonomy and leading tree species to improve

  8. Price floors for emissions trading

    International Nuclear Information System (INIS)

    Wood, Peter John; Jotzo, Frank

    2011-01-01

    Price floors in greenhouse gas emissions trading schemes can guarantee minimum abatement efforts if prices are lower than expected, and they can help manage cost uncertainty, possibly as complements to price ceilings. Provisions for price floors are found in several recent legislative proposals for emissions trading. Implementation however has potential pitfalls. Possible mechanisms are government commitments to buy back permits, a reserve price at auction, or an extra fee or tax on acquittal of emissions permits. Our analysis of these alternatives shows that the fee approach has budgetary advantages and is more compatible with international permit trading than the alternatives. It can also be used to implement more general hybrid approaches to emissions pricing. - Research highlights: → Price floors for emissions trading schemes guarantee a minimum carbon price. → Price floors mean that emissions can be less than specified by the ETS cap. → We examine how price floors can relate to different policy objectives. → We compare different mechanisms for implementing a price floor. → We find that a mechanism where there is an extra tax or fee has advantages.

  9. Holography beyond the horizon and cosmic censorship

    International Nuclear Information System (INIS)

    Levi, Thomas S.; Ross, Simon F.

    2003-01-01

    We investigate the description of the region behind the event horizon in rotating black holes in the AdS conformal field theory correspondence, using the rotating Banados-Teitelboim-Zanelli black hole as a concrete example. We extend a technique introduced by Kraus, Ooguri, and Shenker, based on analytically continuing amplitudes defined in a Euclidean space, to include rotation. In the rotating case, boundary amplitudes again have two different bulk descriptions, involving either integration only over the regions outside the black holes' event horizon, or integration over this region and the region between the event horizon and the Cauchy horizon (inner horizon). We argue that generally, the holographic map will relate the field theory to the region bounded by the Cauchy horizons in spacetime. We also argue that these results suggest that the holographic description of black holes will satisfy strong cosmic censorship

  10. Floor heating systems

    Energy Technology Data Exchange (ETDEWEB)

    Radtke, U

    1984-02-01

    The question of whether PPC- and VPE-floor heating pipes can endure damage when incompletely imbedded in the floor finish is investigated in an experimental setup. An expansion of the pipe, caused by a temperature increase from 20/sup 0/C to 50/sup 0/C was measured and considered too small to deduce the degree of danger from the damage.

  11. Plant component features of forest-bog ecotones of eutrophic paludification in the south of boreal forest zone of West Siberia

    Science.gov (United States)

    Klimova, N. V.; Chernova, N. A.; Pologova, N. N.

    2018-03-01

    Paludified forests formed in transitional forest-bog zone aren’t studied enough, inspite of its high expected diversity and large areas in the south of boreal forest zone of West Siberia. In this article wet birch (Betula pubescens) forests of forest-bog ecotones of eutrophic paludification are investigated on Vasyugan plain with nutrient-rich calcareous clays as soil-forming rocks. Species diversity and ecocoenotic structure of these phytocoenoses are discussed. They correlated with wetness and nutrient-availability of habitats evaluated with indicator values of plants. The participation of hydrophylous species is increasing as wetness of habitats increasing in the forest-to-bog direction like in mesotrophic paludification series. However the number of species is higher in the phytocoenoses of eutrophic paludification. The share of species required to nutrient availability is also higher, both in number and in abundance. A lot of these species are usual for eutrophic boreal forested swamps with groundwater input and absent in forests of mesotrophic paludification. Accordingly the nutrient-availability of habitats is also higher. All these features we connect with birch to be a forest forming species instead of dark-coniferous and with the influence of nutrient-rich parent rocks, which is evident in forest-bog ecotones of Vasyugan plain gradually decreasing together with peat horizon thickening.

  12. Human dose pathways of radionuclides in forests; Forests ecosystems

    Energy Technology Data Exchange (ETDEWEB)

    Rantavaara, A. (Radiation and Nuclear Safety Authority, Research and Environmental Surveillance, Helsinki (Finland))

    2009-06-15

    Forest soil, understorey vegetation and trees are all sources of radionuclides and human radiation doses after contaminating atmospheric deposition. People are exposed to radiation externally from sources outside the body and internally via ingestion and inhalation of radionuclides. Understorey vegetation contributes to ingestion doses through berries, herbs, wild honey, mushrooms and game meat; also trees provide feed to terrestrial birds and big game. During stay in forests people are subject to external radiation from forest floor and overstorey, and they may inhale airborne radioactive aerosol or gaseous radionuclides in ground level air. In the early phase of contamination also resuspended radionuclides may add to the internal dose of people via inhalation. People in Nordic countries are most exposed to radiation via ingestion of radionuclides in wild foods. The distribution of radionuclides in forests is changed by environmental processes, and thereby also the significance of various dose pathways to humans will change with time. External exposure is received in living environment from contaminated stemwood used as building timber and for manufacturing of furniture and other wood products. The aim of this paper is to outline the significance of various human dose pathways of radionuclides in forests considering the public and workers in forestry and production of bioenergy. Examples on effective doses are given based on two historical events, atmospheric nuclear weapon tests (mostly in 1950's and in 1960's) and the Chernobyl nuclear power plant accident in 1986. (au)

  13. Radiocesium transfer through aerial pathways in a South Carolina flooplain forest

    International Nuclear Information System (INIS)

    Shure, D.J.; Gottschalk, M.R.

    1978-01-01

    Cesium-137 cycling studies were conducted in a floodplain forest surrounding a reactor effluent stream at the Savannah River Plant in South Carolina. Throughfall, stem-flow, and litterfall pathways were studied along transects within a 1.5-ha area of floodplain forest. Annual precipitation totaled 1102 liters/m 2 in the study area. Approximately 88% of this rainfall reached the forest floor as throughfall and 4 to 6% as stemflow. Meteorological inputs (fallout) of 137 Cs totaled 3.2 nCi/m 2 for the year. An additional 11 to 15 nCi m -2 year -1 was leached from the floodplain vegetation as throughfall during precipiation. Radiocesium concentrations in throughfall and stem flow were highest in the fall when 137 Cs is readily leached from leaves before leaffall. Radiocesium concentrations in stemflow were always much higher than in throughfall, particularly during the nongrowing season. The annual 137 Cs transfer as stemflow was 2.5 to 4.1 nCi m -2 year -1 , however, which is considerably less (15 to 22%) than the total 137 Cs reaching the forest floor as throughfall. Radiocesium movement in annual litterfall is approximately equal to the total 137 Cs leached from floodplain vegetation during rainfall

  14. Pelvic floor and sexual male dysfunction

    Directory of Open Access Journals (Sweden)

    Antonella Pischedda

    2013-04-01

    Full Text Available The pelvic floor is a complex multifunctional structure that corresponds to the genito- urinary-anal area and consists of muscle and connective tissue. It supports the urinary, fecal, sexual and reproductive functions and pelvic statics. The symptoms caused by pelvic floor dysfunction often affect the quality of life of those who are afflicted, worsening significantly more aspects of daily life. In fact, in addition to providing support to the pelvic organs, the deep floor muscles support urinary continence and intestinal emptying whereas the superficial floor muscles are involved in the mechanism of erection and ejaculation. So, conditions of muscle hypotonia or hypertonicity may affect the efficiency of the pelvic floor, altering both the functionality of the deep and superficial floor muscles. In this evolution of knowledge it is possible imagine how the rehabilitation techniques of pelvic floor muscles, if altered and able to support a voiding or evacuative or sexual dysfunction, may have a role in improving the health and the quality of life.

  15. Texture-contrast profile development across the prairie-forest ecotone in northern Minnesota, USA, and its relation to soil aggregation and clay dispersion.

    Science.gov (United States)

    Kasmerchak, C. S.; Mason, J. A.

    2016-12-01

    Along the prairie-forest ecotone, Alfisols with distinct clay-enriched B horizons are found under forest, established only within the past 4 ka, including outlying patches of prairie groves surrounded by prairie. Grassland soils only 5-10 km away from the vegetation boundary show much weaker texture-contrast. In order for clay to be dispersed it must first be released from aggregates upper horizons, which occurs when exposed top soil undergoes wetting and mechanical stress. The relationship between physiochemical soil characteristics and soil aggregation/clay dispersion is of particular interest in explaining texture-contrast development under forest. Soil samples were collected along a transect in northern Minnesota on gentle slopes in similar glacial sediment. Aggregate stability experiments show Mollisol A and B horizons have the most stable aggregates, while Alfisol E horizons have the weakest aggregates and disintegrate rapidly. This demonstrates the strong influence of OM and exchange chemistry on aggregation. Analysis of other physiochemical soil characteristics such as base saturation and pH follow a gradual decreasing eastward trend across the study sites, and do not abruptly change at the prairie-forest boundary like soil morphology does. Linear models show the strongest relationship between rapid aggregate disintegration and ECEC, although they only explain 47-50% of the variance. Higher surface charge enhances aggregation by allowing for greater potential of cation bridging between OM and clay particles. ECEC also represents multiple soil characteristics such as OC, clay, mineralogy, and carbonate presence, suggesting the relationship between aggregation stability and soil characteristics is not simple. Given the parent material consists of calcareous glacial sediment, abundant Ca2+ and Mg2+ from carbonates weathering also contributes to enhanced aggregation in upper horizons. Differences in the rates of bioturbation, most likely also contribute

  16. Impacts of timber harvesting on soil organic matter, nitrogen, productivity, and health of inland northwest forests

    Science.gov (United States)

    M. F. Jurgensen; A. E. Harvey; R. T. Graham; D. S. Page-Dumroese; J. R. Tonn; M. J. Larsen; T. B. Jain

    1997-01-01

    Soil organic components are important factors in the health and productivity of Inland Northwest forests. Timber harvesting and extensive site preparation (piling, windrowing, or scalping) reduces the amount of surface organic material (woody residues and forest floor layers) over large areas. Some wildfires and severe prescribed burns can have similar consequences....

  17. Quantifying the missing link between forest albedo and productivity in the boreal zone

    Science.gov (United States)

    Hovi, Aarne; Liang, Jingjing; Korhonen, Lauri; Kobayashi, Hideki; Rautiainen, Miina

    2016-11-01

    Albedo and fraction of absorbed photosynthetically active radiation (FAPAR) determine the shortwave radiation balance and productivity of forests. Currently, the physical link between forest albedo and productivity is poorly understood, yet it is crucial for designing optimal forest management strategies for mitigating climate change. We investigated the relationships between boreal forest structure, albedo and FAPAR using a radiative transfer model called Forest Reflectance and Transmittance model FRT and extensive forest inventory data sets ranging from southern boreal forests to the northern tree line in Finland and Alaska (N = 1086 plots). The forests in the study areas vary widely in structure, species composition, and human interference, from intensively managed in Finland to natural growth in Alaska. We show that FAPAR of tree canopies (FAPARCAN) and albedo are tightly linked in boreal coniferous forests, but the relationship is weaker if the forest has broadleaved admixture, or if canopies have low leaf area and the composition of forest floor varies. Furthermore, the functional shape of the relationship between albedo and FAPARCAN depends on the angular distribution of incoming solar irradiance. We also show that forest floor can contribute to over 50 % of albedo or total ecosystem FAPAR. Based on our simulations, forest albedos can vary notably across the biome. Because of larger proportions of broadleaved trees, the studied plots in Alaska had higher albedo (0.141-0.184) than those in Finland (0.136-0.171) even though the albedo of pure coniferous forests was lower in Alaska. Our results reveal that variation in solar angle will need to be accounted for when evaluating climate effects of forest management in different latitudes. Furthermore, increasing the proportion of broadleaved trees in coniferous forests is the most important means of maximizing albedo without compromising productivity: based on our findings the potential of controlling forest

  18. Polychlorinated naphthalenes (PCNs) in Chinese forest soil: Will combustion become a major source?

    International Nuclear Information System (INIS)

    Xu, Yue; Li, Jun; Zheng, Qian; Pan, Suhong; Luo, Chunling; Zhu, Haolin; Nizzetto, Luca; Zhang, Gan

    2015-01-01

    We collected O- and A-horizon soil samples in 26 Chinese mountainous forests to investigate the content, spatial pattern, and potential sources of polychlorinated naphthalenes (PCNs). Spatial patterns were influenced mainly by the approximation to sources and soil organic contents. High concentrations often occurred close to populated or industrialized areas. Combustion-related activities contributed to PCN pollution. Relatively high proportions of CN-73 in northern China may be attributed to coke consumption, while CN-51 could be an indicator of biomass burning in Southwest China. There are evidences that PCNs may largely derived from unintentional production. If uncontrolled, UP-PCN (unintentionally produced PCNs) emissions could increase with industrial development. The abnormally high concentrations at Gongga and Changbai Mountains appear to be associated with the high efficient of forest filter of atmospheric contaminants at these densely forested sites. We question whether this is caused by ecotones between forests, and raise additional questions for future analyses. - Highlights: • PCNs were measured in the O- and A-horizon soil of Chinese mountainous forests. • SOC and source emissions are mainly responsible for PCN pollution. • Thermal processes may contribute to PCN pollution on a regional scale. • CN-73 could be an indicator of coke consumption in northern China. - Combustion-related activities may contributed to a major part of PCN pollution in Chinese background soil

  19. Preliminary study of prairies forested with Eucalyptus sp. at the northwestern Uruguayan soils

    International Nuclear Information System (INIS)

    Carrasco-Letelier, L.; Eguren, G.; Castineira, C.; Parra, O.; Panario, D.

    2004-01-01

    The forestation of Uruguayan natural prairie soil does not always ensure an increase of soil carbon sink. - The land cover change of Uruguayan Forestal Plan provoked biogeochemical changes on horizon Au 1 of Argiudols; in native prairies which were replaced by monoculture Eucalyptus sp. plantation with 20 year rotations as trees. Five fields forested and six natural prairies were compared. The results not only show a statistical significant soil acidification, diminution of soil organic carbon, increase of aliphaticity degree of humic substances, and increase of affinity and capacity of hydrolytic activity from soil microbial communities for forested sites with Eucalyptus sp. but also, a tendency of podzolization and/or mineralization by this kind of land cover changes, with a net soil organic lost of 16.6 tons ha -1 in the horizon Au 1 of soil under Eucalyptus sp. plantation compared with prairie. Besides, these results point out the necessity of correction of the methodology used by assigned Uruguayan commission to assess the national net emission of greenhouse gases, since the mineralization and/or podzolization process detected in forested soil imply a overestimation of soil organic carbon. The biochemical parameters show a statistical significant correlation between the soil organic carbon status and these parameters which were presented as essential for the correct evaluation of Uruguayan soil carbon sink

  20. Fate of nitrogenous fertilizers in forest soil

    International Nuclear Information System (INIS)

    Pang, P.C.K.

    1984-01-01

    The fate of the nitrogenous fertilizers through the processes of denitrification, ammonia volatilization, immobilization and uptake by a conifer is determined, with the aid of 15 N-labelled fertizers. The foliage of Douglas-fir was able to absorb gaseous ammonia under optimal conditions. Denitrification and immobilization of fertilizer-N by forest soil were highest with forest floor samples and decreased with depth. Laboratory studies with four-year-old Douglas-fir demostrated that a higher quantity of fertilizer-N was utilized by trees when the nitrogen was supplied as NO 3 - rather than NH 4 + . (M.A.C.) [pt

  1. Nutrient cycling in Huntington Forest and Turkey Lakes deciduous stands: Nitrogen and sulfur

    Energy Technology Data Exchange (ETDEWEB)

    Mitchell, M J [State Univ. of New York, Syracuse, NY (USA); Foster, N W; Morrison, I K [Forestry Canada, Sault Ste. Marie, ON (Canada); Shepard, J P [National Council of the Paper Industry for Air and Stream Improvement, Gainsville, FL (USA)

    1992-01-01

    A study was conducted to analyze two tolerant hardwood forests that are exhibiting different levels of nitrate and sulfate leaching. Fluxes of N and S at the two sites were compared, and the fluxes of nitrate and sulfate through the forest canopy, forest floor, and mineral soil were determined in order to ascertain whether differences in these fluxes could be explained using information on the N, S, and C biogeochemistry of each site. One site is in the Adirondack region, where the impacts of acidic deposition have been noted; the other site is in central Ontario, and has geological, pedological, and hydrological characteristics that make it potentially sensitive to acidic deposition. An increase in concentration of sulfate and nitrate was noted after passage through the canopy at both sites. The Ontario site showed much greater leaching of nitrate. At the Adirondack site only, there was a marked increase in sulfate flux when water leached from the forest floor through the soil. The mineral soil was the largest pool of N and S for both sites. The Ontario soil had a C/N ratio of 16:1, narrower than the 34:1 ratio of the soil at the other site. The former ratio should favor accumulation of ammonium and nitrate ions, and subsequent nitrate leaching. Laboratory measurements suggest that the forest floor at the Ontario site may have higher N mineralization rates. Fluxes of N and S within the vegetation were generally similar at both sites. The higher nitrate leaching at the Ontario site may be attributed mostly to stand maturity coupled with tree mortality, but the absence of slow decomposing beech leaf litter and lower C/N ratio in the soil may also be contributing factors. 50 refs., 3 figs., 6 tabs.

  2. Tree fern trunks facilitate seedling regeneration in a productive lowland temperate rain forest.

    Science.gov (United States)

    Gaxiola, Aurora; Burrows, Larry E; Coomes, David A

    2008-03-01

    Seedling regeneration on forest floors is often impaired by competition with established plants. In some lowland temperate rain forests, tree fern trunks provide safe sites on which tree species establish, and grow large enough to take root in the ground and persist. Here we explore the competitive and facilitative effects of two tree fern species, Cyathea smithii and Dicksonia squarrosa, on the epiphytic regeneration of tree species in nutrient-rich alluvial forests in New Zealand. The difficulties that seedlings have in establishing on vertical tree fern trunks were indicated by the following observations. First, seedling abundance was greatest on the oldest sections of tree fern trunks, near the base, suggesting that trunks gradually recruited more and more seedlings over time, but many sections of trunk were devoid of seedlings, indicating the difficulty of establishment on a vertical surface. Second, most seedlings were from small-seeded species, presumably because smaller seeds can easily lodge on tree fern trunks. Deer browsing damage was observed on 73% of epiphytic seedlings growing within 2 m of the ground, whereas few seedlings above that height were browsed. This suggests that tree ferns provide refugia from introduced deer, and may slow the decline in population size of deer-preferred species. We reasoned that tree ferns would compete with epiphytic seedlings for light, because below the tree fern canopy photosynthetically active radiation (PAR) was about 1% of above-canopy PAR. Frond removal almost tripled %PAR on the forest floor, leading to a significant increase in the height growth rate (HGR) of seedlings planted on the forest floor, but having no effects on the HGRs of epiphytic seedlings. Our study shows evidence of direct facilitative interactions by tree ferns during seedling establishment in plant communities associated with nutrient-rich soils.

  3. Cultural and Chronological Horizons and the Problem of the Early Sarmatian Culture Formation

    Directory of Open Access Journals (Sweden)

    Yablonsky Leonid Teodorovich

    2015-12-01

    Full Text Available On the materials of Eurasian early nomads’ archaeology we highlight the South Ural cultural and historical area (UCHA. Geographically it includes steppe regions of West Kazakhstan, Chelyabinsk and Orenburg regions, steppe and forest steppe zones of the Republic of Bashkortostan. There were similar cultural processes that led to the Early Sarmatian archaeological culture formation in the Early Iron Age. Under the cultural and chronological horizon we understand the geographic region that is significantly larger than UCHA. Practically it has no geographic boundaries. Specificity of the horizon is that at a certain chronological stage (phase artifacts and their complexes, signs of spiritual culture are widely distributed that will mark the horizon – the horizon markers such as well known Scythian triad. Global chronological scheme of the Southern Trans-Urals cultural and historical area can be represented as follows: “Sauromatian” cultural and chronological horizon – the second half of the 6th – the end of the 4th (3rd centuries B.C. – Phase “A” – the second half of the 6th – the middle of the 5th centuries B.C. – Phase “B” – the second half of the 5th – the third quarter of the 4th centuries B.C. – Phase “C” – the third quarter of the 4th – the 3rd century B.C. Typologically the burial grounds like Filippovka I and Perevolochan can be attributed to the Early-Sarmatian archaeological culture, i.e. to the time of the ethnic consciousness formation of suspected archaeological Early Sarmatians. In this period ordinary mounds and graves appear along with the elite ones. It is advisable to consider the sites of the “Sauromatian” and Early-Sarmatian cultures of the South Urals of the end of the 5th-3rd centuries B.C. as a single culture of the early nomads.

  4. Maxillary Sinus Floor Augmentation

    DEFF Research Database (Denmark)

    Starch-Jensen, Thomas; Jensen, Janek Dalsgaard

    2017-01-01

    , radiological and histomorphometric outcome as well as complications are presented after maxillary sinus floor augmentation applying the lateral window technique with a graft material, maxillary sinus membrane elevation without a graft material and osteotome-mediated sinus floor elevation with or without...

  5. Involvement of allelopathy in inhibition of understory growth in red pine forests.

    Science.gov (United States)

    Kato-Noguchi, Hisashi; Kimura, Fukiko; Ohno, Osamu; Suenaga, Kiyotake

    2017-11-01

    Japanese red pine (Pinus densiflora Sieb. et Zucc.) forests are characterized by sparse understory vegetation although sunlight intensity on the forest floor is sufficient for undergrowth. The possible involvement of pine allelopathy in the establishment of the sparse understory vegetation was investigated. The soil of the red pine forest floor had growth inhibitory activity on six test plant species including Lolium multiflorum, which was observed at the edge of the forest but not in the forest. Two growth inhibitory substances were isolated from the soil and characterized to be 15-hydroxy-7-oxodehydroabietate and 7-oxodehydroabietic acid. Those compounds are probably formed by degradation process of resin acids. Resin acids are produced by pine and delivered into the soil under the pine trees through balsam and defoliation. Threshold concentrations of 15-hydroxy-7-oxodehydroabietate and 7-oxodehydroabietic acid for the growth inhibition of L. multiflorum were 30 and 10μM, respectively. The concentrations of 15-hydroxy-7-oxodehydroabietate and 7-oxodehydroabietic acid in the soil were 312 and 397μM, respectively, which are sufficient concentrations to cause the growth inhibition because of the threshold. These results suggest that those compounds are able to work as allelopathic agents and may prevent from the invasion of herbaceous plants into the forests by inhibiting their growth. Therefore, allelopathy of red pine may be involved in the formation of the sparse understory vegetation. Copyright © 2017 Elsevier GmbH. All rights reserved.

  6. The effect of sub-floor heating on house-dust-mite populations on floors and in furniture.

    Science.gov (United States)

    de Boer, Rob

    2003-01-01

    It is well known that dehydrating conditions for house dust mites can be created by simply raising the temperature, causing loss of body water and eventually death. Thus, it can be expected that conditions for dust mites are less favourable on floors supplied with sub-floor heating. This was examined in a study of 16 houses with sub-floor heating and 21 without. The pattern of changes in air humidity and temperature on the floors was investigated and compared to known data of the tolerance of dust mites. Also the resident mite populations were compared. Floors with sub-floor heating had, on average, fewer mites, but the difference with unheated floors was small. It was remarkable that mite numbers were also lower in upholstered furniture. Another important observation was that some houses with sub-floor heating had high mite numbers, indicating that this type of heating is compatible with a thriving mite population. Temperature and humidity conditions of heated floors may allow mites not only to survive, but also to remain active in winter. A moderate increase in temperature, a moderate decrease in (absolute) air humidity, or a combination of both, will suffice to keep the humidity all winter below the Critical Equilibrium Humidity, the level of air humidity that is critical for mite growth and reproduction, hence for allergen production. However, it is argued that measures to suppress allergen production by house dust mites are likely to be far more effective if taken in summer rather than in winter.

  7. Sulfur impacts on forest health in west-central Alberta

    International Nuclear Information System (INIS)

    Maynard, D.G.; Stadt, J.J.; Mallett, K.I.; Volney, W.J.A.

    1994-01-01

    A study was conducted to evaluate forest health and tree growth in relation to sulfur deposition in mature and immature lodgepole pine and mature trembling aspen. Soil samples were taken in forests near two sour gas processing plants in west-central Alberta. The soil sample sites were classified into high, medium and low deposition classes. The impact of sulfur deposition on soil and foliar chemistry, tree growth, and forest health was evaluated. The analysis of tree growth, using radial increments, revealed no impact associated with the sulfur deposition class. The only indicators of extensive sulfur impacts on major forest communities detected to date are elevated sulfur concentrations in the surface organic horizon and foliage, the proportion of healthy lodgepole pines, and a depression in the annual specific volume increment. No evidence of widespread forest decline has been found. 42 refs., 35 tabs., 29 figs

  8. Development of floor smear sampler (floor radioactive contamination measuring instrument) for nuclear facilities

    International Nuclear Information System (INIS)

    Miyagawa, Minoru; Ito, Haruo; Nozawa, Katsuro; Shinohara, Yotaro; Hashimoto, Hiroshi.

    1980-01-01

    The control of the floor contamination with radioactive substances in nuclear facilities is strictly carried out by smear method, in which the contaminants on floor surfaces are wiped off with filter papers or cloths, and the contamination density on the floor surfaces is measured through their intensity of radioactivity. This wiping work is laborious since it is carried out in leaning-over posture when many samples must be taken in wide floor area. Therefore, to achieve labor saving in this work, an automatic sampler was developed. In the floor smear sampler developed, samples are taken on long band type wiping cloths only by handle operation, and the sample numbers are printed. When many samples are taken in wide floor area, this is especially effective, and the labor saving by 1/3 to 1/2 can be achieved. At present, this sampler is put in practical use in Hamaoka Nuclear Power Station. At the time of trial manufacture, the method of wiping, the mechanisms of wiping, cloth feeding and running, the contact pressure and the number of times of wiping affecting wiping efficiency and the required torque of a motor were examined. The developed sampler is that of constant contact pressure, vibration wiping type, and the rate of sampling is 10 sec per one sample. 100 samples can be taken on one roll of wiping cloth. The results of performance test are reported. (Kako, I.)

  9. Forest canopy water fluxes can be estimated using canopy structure metrics derived from airborne light detection and ranging (LiDAR)

    DEFF Research Database (Denmark)

    Schumacher, Johannes; Christiansen, Jesper Riis

    2015-01-01

    Forests contribute to improve water quality, affect drinking water resources, and therefore influence water supply on a regional level. The forest canopy structure affects the retention of precipitation (Pr) in the canopy and hence the amount of water transferred to the forest floor termed canopy...... impacts water resources on a large scale in regions where forests play a major role in water resource management....

  10. .i.Moraria brevipes./i. (Crustacea: Copepoda) in South Bohemian forest soils

    Czech Academy of Sciences Publication Activity Database

    Háněl, Ladislav; Christian, E.

    2004-01-01

    Roč. 68, - (2004), s. 169-171 ISSN 1211-376X R&D Projects: GA ČR(CZ) GA206/99/1416 Institutional research plan: CEZ:AV0Z6066911 Keywords : forest floor * spruce * Crustacea Subject RIV: EH - Ecology, Behaviour

  11. Horizon Entropy from Quantum Gravity Condensates.

    Science.gov (United States)

    Oriti, Daniele; Pranzetti, Daniele; Sindoni, Lorenzo

    2016-05-27

    We construct condensate states encoding the continuum spherically symmetric quantum geometry of a horizon in full quantum gravity, i.e., without any classical symmetry reduction, in the group field theory formalism. Tracing over the bulk degrees of freedom, we show how the resulting reduced density matrix manifestly exhibits a holographic behavior. We derive a complete orthonormal basis of eigenstates for the reduced density matrix of the horizon and use it to compute the horizon entanglement entropy. By imposing consistency with the horizon boundary conditions and semiclassical thermodynamical properties, we recover the Bekenstein-Hawking entropy formula for any value of the Immirzi parameter. Our analysis supports the equivalence between the von Neumann (entanglement) entropy interpretation and the Boltzmann (statistical) one.

  12. Event horizon image within black hole shadow

    OpenAIRE

    Dokuchaev, V. I.; Nazarova, N. O.

    2018-01-01

    The external border of the black hole shadow is washed out by radiation from matter plunging into black hole and approaching the event horizon. This effect will crucially influence the results of future observations by the Event Horizon Telescope. We show that gravitational lensing of the luminous matter plunging into black hole provides the event horizon visualization within black hole shadow. The lensed image of the event horizon is formed by the last highly red-shifted photons emitted by t...

  13. Gaseous mercury fluxes from forest soils in response to forest harvesting intensity: A field manipulation experiment

    International Nuclear Information System (INIS)

    Mazur, M.; Mitchell, C.P.J.; Eckley, C.S.; Eggert, S.L.; Kolka, R.K.; Sebestyen, S.D.; Swain, E.B.

    2014-01-01

    Forest harvesting leads to changes in soil moisture, temperature and incident solar radiation, all strong environmental drivers of soil–air mercury (Hg) fluxes. Whether different forest harvesting practices significantly alter Hg fluxes from forest soils is unknown. We conducted a field-scale experiment in a northern Minnesota deciduous forest wherein gaseous Hg emissions from the forest floor were monitored after two forest harvesting prescriptions, a traditional clear-cut and a clearcut followed by biomass harvest, and compared to an un-harvested reference plot. Gaseous Hg emissions were measured in quadruplicate at four different times between March and November 2012 using Teflon dynamic flux chambers. We also applied enriched Hg isotope tracers and separately monitored their emission in triplicate at the same times as ambient measurements. Clearcut followed by biomass harvesting increased ambient Hg emissions the most. While significant intra-site spatial variability was observed, Hg emissions from the biomass harvested plot (180 ± 170 ng m −2 d −1 ) were significantly greater than both the traditional clearcut plot (− 40 ± 60 ng m −2 d −1 ) and the un-harvested reference plot (− 180 ± 115 ng m −2 d −1 ) during July. This difference was likely a result of enhanced Hg 2+ photoreduction due to canopy removal and less shading from downed woody debris in the biomass harvested plot. Gaseous Hg emissions from more recently deposited Hg, as presumably representative of isotope tracer measurements, were not significantly influenced by harvesting. Most of the Hg tracer applied to the forest floor became sequestered within the ground vegetation and debris, leaf litter, and soil. We observed a dramatic lessening of tracer Hg emissions to near detection levels within 6 months. As post-clearcutting residues are increasingly used as a fuel or fiber resource, our observations suggest that gaseous Hg emissions from forest soils will increase, although it

  14. TU-C-HORIZONS-01: The Expanding Horizons Travel Grant Program: ePosters and Discussion

    International Nuclear Information System (INIS)

    Siewerdsen, J; Jeraj, R

    2016-01-01

    The Expanding Horizons travel grant program provides opportunity for students and trainees to broaden the scope of scientific meetings they attend and gain insight from research outside traditional domains of medical physics. Through participation in such conferences, early-career researchers are introduced to new topics with relevance to medical physics research as a means to expand the scientific horizons of our discipline. This year, 21 Expanding Horizons travel grants were awarded, granting travel to 17 conferences, including: Radiomics, the World Molecular Imaging Society (WMIS), the 3D Printing Conference and Expo, the GPU Technology Conference, the SIAM Imaging Science Conference, the Human Brain Mapping Conference, the OSA Conference on Clinical and Translational Biophotonics, the Society for Neuroscience, the AACR Conference on Tumor Microenvironment, and the Conference on Knowledge Discovery and Data Mining. The Expanding Horizons electronic poster session gives a venue for AAPM conference attendees to meet and discuss with awardees, learn the hot topics and emerging research areas presented at these conferences, and understand the relevance to future medical physics research.

  15. TU-C-HORIZONS-01: The Expanding Horizons Travel Grant Program: ePosters and Discussion

    Energy Technology Data Exchange (ETDEWEB)

    Siewerdsen, J [Johns Hopkins University, Baltimore, MD (United States); Jeraj, R [University of Wisconsin, Madison, WI (United States)

    2016-06-15

    The Expanding Horizons travel grant program provides opportunity for students and trainees to broaden the scope of scientific meetings they attend and gain insight from research outside traditional domains of medical physics. Through participation in such conferences, early-career researchers are introduced to new topics with relevance to medical physics research as a means to expand the scientific horizons of our discipline. This year, 21 Expanding Horizons travel grants were awarded, granting travel to 17 conferences, including: Radiomics, the World Molecular Imaging Society (WMIS), the 3D Printing Conference and Expo, the GPU Technology Conference, the SIAM Imaging Science Conference, the Human Brain Mapping Conference, the OSA Conference on Clinical and Translational Biophotonics, the Society for Neuroscience, the AACR Conference on Tumor Microenvironment, and the Conference on Knowledge Discovery and Data Mining. The Expanding Horizons electronic poster session gives a venue for AAPM conference attendees to meet and discuss with awardees, learn the hot topics and emerging research areas presented at these conferences, and understand the relevance to future medical physics research.

  16. Evaporation components of a boreal forest: variations during the growing season

    Science.gov (United States)

    Grelle, A.; Lundberg, A.; Lindroth, A.; Morén, A.-S.; Cienciala, E.

    1997-10-01

    To improve the understanding of interactions between the boreal forest and the climate system as a key issue for global climate change, the water budget of a mixed pine and spruce forest in central Sweden was estimated by measurements of the water flux components and the total evaporation flux during the period 16 May-31 October 1995. Total evaporation was measured using eddy correlation and the components were obtained using measurements of precipitation, throughfall, tree transpiration, and forest floor evaporation. On a daily basis, tree transpiration was the dominant evaporation component during the vegetation period. However, it could be efficiently blocked by a wet canopy associated with large interception evaporation. The accumulated total evaporation was 399 mm, transpiration was 243 mm, forest floor evaporation was 56 mm and interception evaporation was 74 mm. The accumulated sum of interception, transpiration, and floor evaporation was 51 mm larger than the actual measured total evaporation. This difference was mainly attributed to the fact that transpiration was measured in a rather dense 50-year-old stand while total evaporation represented the average conditions of older, roughly 100-year-old stands. To compare eddy-correlation measurements with small-scale measurements of evaporation components, a source area analysis was made to select the flux data that give the best representation of the investigated stand. Especially under stable atmospheric conditions the requirements for surface homogeneity were very high and extreme care had to be taken to be aware of the flux source areas. Canopy water storage was determined by two methods: by the water balance of the canopy, which gave a result of 3.3 mm; and by the so-called minimum method based on plots of throughfall versus precipitation, which gave a much lower value of 1.5 mm. Seasonal interception evaporation constituted 30% of the precipitation.

  17. Linear Alkylbenzenesulfonates in indoor Floor Dust

    DEFF Research Database (Denmark)

    Madsen, Jørgen Øgaard; Wolkoff, Peder; Madsen, Jørgen Øgaard

    1999-01-01

    The amount of Linear Alkylbenzenesulfonates (LAS) in the particle fraction of floor dust sampled from 7 selected public buildings varied between 34 and 1500 microgram per gram dust, while the contents of the fibre fractions generally were higher with up to 3500 microgram LAS/g dust. The use...... of a cleaning agent with LAS resulted in an increase of the amount of LAS in the floor dust after floor wash relative to just before floor wash. However, the most important source of LAS in the indoor floor dust appears to be residues of detergent in clothing. Thus, a newly washed shirt contained 2960 microgram...

  18. Cauchy horizons in Gowdy spacetimes

    International Nuclear Information System (INIS)

    Chrusciel, Piotr T; Lake, Kayll

    2004-01-01

    We analyse exhaustively the structure of non-degenerate Cauchy horizons in Gowdy spacetimes, and we establish existence of a large class of non-polarized Gowdy spacetimes with such horizons. Our results here, together with the deep new results of Ringstroem, establish strong cosmic censorship in (toroidal) Gowdy spacetimes

  19. Effects of Floor Covering Resistance of a Radiant Floor on System Energy and Exergy Performances

    DEFF Research Database (Denmark)

    Kazanci, Ongun Berk; Shukuya, Masanori; Olesen, Bjarne W.

    2016-01-01

    Floor covering resistance (material and thickness) can be influenced by subjective choices (architectural design, interior design, texture, etc.) with significant effects on the performance of a radiant heating and cooling system. To study the effects of floor covering resistance on system...... performance, a water-based radiant floor heating and cooling system (dry, wooden construction) was considered to be coupled to an air-to-water heat pump, and the effects of varying floor covering resistances (0.05 m2K/W, 0.09 m2K/W and 0.15 m2K/W) on system performance were analyzed in terms of energy...... and exergy. In order to achieve the same heating and cooling outputs, higher average water temperatures are required in the heating mode (and lower temperatures in the cooling mode) with increasing floor covering resistance. These temperature requirements decrease the heat pump’s performance (lower...

  20. Forest type effects on the retention of radiocesium in organic layers of forest ecosystems affected by the Fukushima nuclear accident

    Science.gov (United States)

    Koarashi, Jun; Atarashi-Andoh, Mariko; Matsunaga, Takeshi; Sanada, Yukihisa

    2016-12-01

    The Fukushima Daiichi nuclear power plant disaster caused serious radiocesium (137Cs) contamination of forest ecosystems over a wide area. Forest-floor organic layers play a key role in controlling the overall bioavailability of 137Cs in forest ecosystems; however, there is still an insufficient understanding of how forest types influence the retention capability of 137Cs in organic layers in Japanese forest ecosystems. Here we conducted plot-scale investigations on the retention of 137Cs in organic layers at two contrasting forest sites in Fukushima. In a deciduous broad-leaved forest, approximately 80% of the deposited 137Cs migrated to mineral soil located below the organic layers within two years after the accident, with an ecological half-life of approximately one year. Conversely, in an evergreen coniferous forest, more than half of the deposited 137Cs remained in the organic layers, with an ecological half-life of 2.1 years. The observed retention behavior can be well explained by the tree phenology and accumulation of 137Cs associated with litter materials with different degrees of degradation in the organic layers. Spatial and temporal patterns of gamma-ray dose rates depended on the retention capability. Our results demonstrate that enhanced radiation risks last longer in evergreen coniferous forests than in deciduous broad-leaved forests.

  1. Upland Trees Contribute to Exchange of Nitrous Oxide (N2O) in Forest Ecosystems

    Science.gov (United States)

    Tian, H.; Thompson, R.; Canadell, J.; Winiwarter, W.; Machacova, K.; Maier, M.; Halmeenmäki, E.; Svobodova, K.; Lang, F.; Pihlatie, M.; Urban, O.

    2017-12-01

    The increase in atmospheric nitrous oxide (N2O) concentration contributes to the acceleration of the greenhouse effect. However, the role of trees in the N2O exchange of forest ecosystems is still an open question. While the soils of temperate and boreal forests were shown to be a natural source of N2O, trees have been so far overlooked in the forest N2O inventories. We determined N2O fluxes in common tree species of boreal and temperate forests: Scots pine (Pinus sylvestris), Norway spruce (Picea abies), downy and silver birch (Betula pubescens, B. pendula), and European beech (Fagus sylvatica). We investigated (1) whether these tree species exchange N2O with the atmosphere under natural field conditions, (2) how the tree N2O fluxes contribute to the forest N2O balance, and (3) whether these fluxes show seasonal dynamics. The studies were performed in a boreal forest (SMEAR II station, Finland; June 2014 - May 2015) and two temperate mountain forests (White Carpathians, Czech Republic; Black Forest, Germany; June and July 2015). Fluxes of N2O in mature tree stems and forest floor were measured using static chamber systems followed by chromatographic and photo-acoustic analyses of N2O concentration changes. Pine, spruce and birch trees were identified as net annual N2O sources. Spruce was found the strongest emitter (0.27 mg ha-1 h-1) amounting thus up to 2.5% of forest floor N2O emissions. All tree species showed a substantial seasonality in stem N2O flux that was related to their physiological activity and climatic variables. In contrast, stems of beech trees growing at soils consuming N2O may act as a substantial sink of N2O from the atmosphere. Consistent N2O consumption by tree stems ranging between -12.1 and -35.2 mg ha-1 h-1 and contributing by up to 3.4% to the forest floor N2O uptake is a novel finding in contrast to current studies presenting trees as N2O emitters. To understand these fluxes, N2O exchange of photoautotrophic organisms associated with

  2. Effect of industrial pollution on behaviour of radionuclides in forest ecosystems; Forests ecosystems

    Energy Technology Data Exchange (ETDEWEB)

    Outola, I. (STUK-Radiation and Nuclear Safety Authority, Helsinki (Finland))

    2009-06-15

    To investigate how and to what extent industrial pollution affects the behaviour of radionuclides in forest ecosystems, studies were conducted in the vicinity of two Cu-Ni smelters: one in a pine forest at Harjavalta, Finland, and the other in a spruce forest at Monchegorsk, Russia. Industrial pollution had significant effects on the distribution of radionuclides in soil horizons. With the increase in pollution towards the smelter, radionuclides were accumulated more in the litter layer because the conversion of litter into organic material was diminished due to inhibited microbial activity. As a result, the organic layer contained less radionuclides towards the smelter. The effect of industrial pollution on soil-to-plant transfer was complex. The effect varied with radionuclide, plant species and also on forest type. For 137Cs, soil-to-plant transfer decreased significantly as industrial pollution increased in pine forest, whereas the decrease was less pronounced in spruce forest. Root uptake of 239,240Pu by plants is extremely small, and plant contamination by resuspended soil is an important factor in considering the soil-to-plant transfer of this radionuclide. In spruce forest, more plutonium was transferred into plants when pollution load increased due to resuspension of litter particles, which contained higher concentrations of plutonium in the vicinity of the smelter. Soil-to-plant transfer of plutonium was much less affected in pine forests contaminated with industrial pollution. This research clearly indicates the sensitivity of the northern forest ecosystem to inorganic pollutants. Prediction of the soil-to-plant transfer of radionuclides in industrially polluted forest ecosystems requires detailed information on the total deposition, vertical distribution of radionuclides in soil, soil microbiological factors, other soil parameters as well as the rooting depths of the plants. (LN)

  3. Earthworm effects on the incorporation of litter C and N into soil organic matter in a sugar maple forest.

    Science.gov (United States)

    Fahey, Timothy J; Yavitt, Joseph B; Sherman, Ruth E; Maerz, John C; Groffman, Peter M; Fisk, Melany C; Bohlen, Patrick J

    2013-07-01

    To examine the mechanisms of earthworm effects on forest soil C and N, we double-labeled leaf litter with 13C and 15N, applied it to sugar maple forest plots with and without earthworms, and traced isotopes into soil pools. The experimental design included forest plots with different earthworm community composition (dominated by Lumbricus terrestris or L. rubellus). Soil carbon pools were 37% lower in earthworm-invaded plots largely because of the elimination of the forest floor horizons, and mineral soil C:N was lower in earthworm plots despite the mixing of high C:N organic matter into soil by earthworms. Litter disappearance over the first winter-spring was highest in the L. terrestris (T) plots, but during the warm season, rapid loss of litter was observed in both L. rubellus (R) and T plots. After two years, 22.0% +/- 5.4% of 13C released from litter was recovered in soil with no significant differences among plots. Total recovery of added 13C (decaying litter plus soil) was much higher in no-worm (NW) plots (61-68%) than in R and T plots (20-29%) as much of the litter remained in the former whereas it had disappeared in the latter. Much higher percentage recovery of 15N than 13C was observed, with significantly lower values for T than R and NW plots. Higher overwinter earthworm activity in T plots contributed to lower soil N recovery. In earthworm-invaded plots isotope enrichment was highest in macroaggregates and microaggregates whereas in NW plots silt plus clay fractions were most enriched. The net effect of litter mixing and priming of recalcitrant soil organic matter (SOM), stabilization of SOM in soil aggregates, and alteration of the soil microbial community by earthworm activity results in loss of SOM and lowering of the C:N ratio. We suggest that earthworm stoichiometry plays a fundamental role in regulating C and N dynamics of forest SOM.

  4. Effects of litter manipulation on litter decomposition in a successional gradients of tropical forests in southern China

    DEFF Research Database (Denmark)

    Chen, Hao; Gurmesa, Geshere A.; Liu, Lei

    2014-01-01

    Global changes such as increasing CO2, rising temperature, and land-use change are likely to drive shifts in litter inputs to forest floors, but the effects of such changes on litter decomposition remain largely unknown. We initiated a litter manipulation experiment to test the response of litter...... decomposition to litter removal/addition in three successional forests in southern China, namely masson pine forest (MPF), mixed coniferous and broadleaved forest (MF) and monsoon evergreen broadleaved forest (MEBF). Results showed that litter removal decreased litter decomposition rates by 27%, 10% and 8...

  5. Horizon shells and BMS-like soldering transformations

    Energy Technology Data Exchange (ETDEWEB)

    Blau, Matthias [Albert Einstein Center for Fundamental Physics,Institute for Theoretical Physics, University of Bern,Sidlerstrasse 5, 3012 Bern (Switzerland); O’Loughlin, Martin [University of Nova Gorica,Vipavska 13, 5000 Nova Gorica (Slovenia)

    2016-03-07

    We revisit the theory of null shells in general relativity, with a particular emphasis on null shells placed at horizons of black holes. We study in detail the considerable freedom that is available in the case that one solders two metrics together across null hypersurfaces (such as Killing horizons) for which the induced metric is invariant under translations along the null generators. In this case the group of soldering transformations turns out to be infinite dimensional, and these solderings create non-trivial horizon shells containing both massless matter and impulsive gravitational wave components. We also rephrase this result in the language of Carrollian symmetry groups. To illustrate this phenomenon we discuss in detail the example of shells on the horizon of the Schwarzschild black hole (with equal interior and exterior mass), uncovering a rich classical structure at the horizon and deriving an explicit expression for the general horizon shell energy-momentum tensor. In the special case of BMS-like soldering supertranslations we find a conserved shell-energy that is strikingly similar to the standard expression for asymptotic BMS supertranslation charges, suggesting a direct relation between the physical properties of these horizon shells and the recently proposed BMS supertranslation hair of a black hole.

  6. The influence of tree species composition on the storage and mobility of semivolatile organic compounds in forest soils

    Energy Technology Data Exchange (ETDEWEB)

    Komprdová, Klára, E-mail: komprdova@recetox.muni.cz [RECETOX (Research Centre for Toxic Compounds in the Environment), Kamenice 753/5, CZ-625 00 Brno (Czech Republic); Komprda, Jiří [RECETOX (Research Centre for Toxic Compounds in the Environment), Kamenice 753/5, CZ-625 00 Brno (Czech Republic); Menšík, Ladislav [Mendel University in Brno, Faculty of Forestry and Wood Technology, Zemědělská 3, Brno 613 00 (Czech Republic); Vaňková, Lenka [RECETOX (Research Centre for Toxic Compounds in the Environment), Kamenice 753/5, CZ-625 00 Brno (Czech Republic); Kulhavý, Jiří [Mendel University in Brno, Faculty of Forestry and Wood Technology, Zemědělská 3, Brno 613 00 (Czech Republic); Nizzetto, Luca [RECETOX (Research Centre for Toxic Compounds in the Environment), Kamenice 753/5, CZ-625 00 Brno (Czech Republic); Norwegian Institute for Water Research, Gaustadalleen 21, NO-0349 Oslo (Norway)

    2016-05-15

    Soil contamination with PCBs and PAHs in adjacent forest plots, characterized by a distinct composition in tree species (spruce only, mixed and beech only), was analyzed to investigate the influence of ecosystem type on contaminant mobility in soil under very similar climate and exposure conditions. Physical-chemical properties and contaminant concentrations in litter (L), organic (F, H) and mineral (A, B) soil horizons were analyzed. Contaminant distribution in the soil core varied both in relation to forest type and contaminant group/properties. Contaminant mobility in soil was assessed by examining the ratios of total organic carbon (TOC)-standardized concentrations across soil horizons (Enrichment factors, EF{sub TOC}) and the relationship between EF{sub TOC} and the octanol-water equilibrium partitioning coefficient (K{sub OW}). Contaminant distribution appeared to be highly unsteady, with pedogenic/biogeochemical drivers controlling contaminant mobility in organic layers and leaching controlling accumulation in mineral layers. Lighter PCBs displayed higher mobility in all forest types primarily controlled by leaching and, to a minor extent, diffusion. Pedogenic processes controlling the formation of soil horizons were found to be crucial drivers of PAHs and heavier PCBs distribution. All contaminants appeared to be more mobile in the soil of the broadleaved plot, followed by mixed canopy and spruce forest. Increasing proportion of deciduous broadleaf species in the forest can thus lead to faster degradation or the faster leaching of PAHs and PCBs. The composition of humic substances was found to be a better descriptor of contaminant concentration than TOC. - Highlights: • Tree species composition influences vertical distribution of PCBs and PAHs in soils. • PCBs and PAHs were more mobile in the soil of the broadleaved plot. • Low molecular weight PCBs displayed higher mobility in all forest types. • Humic substances were important descriptors of

  7. The influence of tree species composition on the storage and mobility of semivolatile organic compounds in forest soils

    International Nuclear Information System (INIS)

    Komprdová, Klára; Komprda, Jiří; Menšík, Ladislav; Vaňková, Lenka; Kulhavý, Jiří; Nizzetto, Luca

    2016-01-01

    Soil contamination with PCBs and PAHs in adjacent forest plots, characterized by a distinct composition in tree species (spruce only, mixed and beech only), was analyzed to investigate the influence of ecosystem type on contaminant mobility in soil under very similar climate and exposure conditions. Physical-chemical properties and contaminant concentrations in litter (L), organic (F, H) and mineral (A, B) soil horizons were analyzed. Contaminant distribution in the soil core varied both in relation to forest type and contaminant group/properties. Contaminant mobility in soil was assessed by examining the ratios of total organic carbon (TOC)-standardized concentrations across soil horizons (Enrichment factors, EF_T_O_C) and the relationship between EF_T_O_C and the octanol-water equilibrium partitioning coefficient (K_O_W). Contaminant distribution appeared to be highly unsteady, with pedogenic/biogeochemical drivers controlling contaminant mobility in organic layers and leaching controlling accumulation in mineral layers. Lighter PCBs displayed higher mobility in all forest types primarily controlled by leaching and, to a minor extent, diffusion. Pedogenic processes controlling the formation of soil horizons were found to be crucial drivers of PAHs and heavier PCBs distribution. All contaminants appeared to be more mobile in the soil of the broadleaved plot, followed by mixed canopy and spruce forest. Increasing proportion of deciduous broadleaf species in the forest can thus lead to faster degradation or the faster leaching of PAHs and PCBs. The composition of humic substances was found to be a better descriptor of contaminant concentration than TOC. - Highlights: • Tree species composition influences vertical distribution of PCBs and PAHs in soils. • PCBs and PAHs were more mobile in the soil of the broadleaved plot. • Low molecular weight PCBs displayed higher mobility in all forest types. • Humic substances were important descriptors of contaminant

  8. Super-horizon primordial black holes

    International Nuclear Information System (INIS)

    Harada, Tomohiro; Carr, B.J.

    2005-01-01

    We discuss a new class of solutions to the Einstein equations which describe a primordial black hole (PBH) in a flat Friedmann background. Such solutions arise if a Schwarzschild black hole is patched onto a Friedmann background via a transition region. They are possible providing the black hole event horizon is larger than the cosmological apparent horizon. Such solutions have a number of strange features. In particular, one has to define the black hole and cosmological horizons carefully and one then finds that the mass contained within the black hole event horizon decreases when the black hole is larger than the Friedmann cosmological apparent horizon, although its area always increases. These solutions involve two distinct future null infinities and are interpreted as the conversion of a white hole into a black hole. Although such solutions may not form from gravitational collapse in the same way as standard PBHs, there is nothing unphysical about them, since all energy and causality conditions are satisfied. Their conformal diagram is a natural amalgamation of the Kruskal diagram for the extended Schwarzschild solution and the conformal diagram for a black hole in a flat Friedmann background. In this paper, such solutions are obtained numerically for a spherically symmetric universe containing a massless scalar field, but it is likely that they exist for more general matter fields and less symmetric systems

  9. A comparative study on thermal efficiency between the present floor and a ceramic floor

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Y.M.; Kim, K.S. [Korea Institute of Science and Technology, Seoul (Korea, Republic of); Choi, B.S. [Kyung Hee University, Yongin (Korea, Republic of); Ko, J.S.; Park, S.K. [Bomwoo and Co. LTD., Kwangju (Korea, Republic of)

    1999-04-01

    A ceramic floor with improved thermal conductivity and efficiency has been developed in this study. The new ceramic floor minimizes the shrinkage rate to below 0.07% and shows almost no cleavage. There is no need to repair the ceramic floor because its bottom surface is flat. It especially shows an excellent performance in the test of a compressive strength (300 kg/cm{sup 2} based on 28 days), a flexural strength (64 kg/cm{sup 2} based on 28 days), and a convenient pressing. It is lighter than the present floor and it is expected to be applicable for a self-leveling ceramic motar in the residences and apartments. It shows an excellent character in the thermal conductivity and other physical properties compare to the present cement mortar. 5 refs., 3 figs., 2 tabs.

  10. Floors: Care and Maintenance.

    Science.gov (United States)

    Post Office Dept., Washington, DC.

    Guidelines, methods and policies regarding the care and maintenance of post office building floors are overviewed in this handbook. Procedures outlined are concerned with maintaining a required level of appearance without wasting manpower. Flooring types and characteristics and the particular cleaning requirements of each type are given along with…

  11. Dynamics of radionuclides in forest ecosystems

    International Nuclear Information System (INIS)

    Steiner, M.

    2004-01-01

    The unique physiology and the layered structure of forest ecosystems result in dynamic transport and transfer processes which greatly differ from those in agricultural ecosystems. Radionuclides are retained in the upper organic horizons of forest soil for several decades and remain highly available for uptake by fungi and green plants. Contamination levels of mushrooms and game may therefore by far exceed those of agricultural produce. The efficient cycling of nutrients and radionuclides, which is characteristic for ecosystems poor in nutrients, can largely be attributed to forest soil with its complex and multi-layered structure and fungal activity. Fungi directly affect dynamic processes, playing a key role in the mobilization, uptake and translocation of nutrients and radionuclides. Fungal fruit bodies may be highly contaminated foodstuff and fodder. They are most likely the cause of the surprising trend of increasing contamination of wild boar which has been observed in the last few years in Germany. This paper is intended to give a qualitative survey of dynamic transport processes in forests and their relevance for radiation exposure to man. (orig.)

  12. Exchangeable hydrogen explains the pH of spodosol Oa horizons

    Science.gov (United States)

    Ross, D.S.; David, M.B.; Lawrence, G.B.; Bartlett, R.J.

    1996-01-01

    The chemistry of extremely acid Oa horizons does not conform to traditional pH, Al, and base saturation relationships. Results from two separate studies of northeastern U.S. forested soils were used to investigate relationships between pH in water or dilute salt solutions and other soil characteristics. In Oa horizons with pH below 4, soil pH in dilute CaCl2 solution was correlated with exchangeable H+ measured either by titration (r = -0.88, P = 0.0001, n = 142) or by electrode (r = -0.89, P = 0.0001, n = 45). Exchangeable H+ expressed as a percentage of the cation-exchange capacity (CEC) was linear with pH and showed similar slopes for data from both studies. For all samples, pHw = 4.21 - 1.80 x H+/CEC (R2 = 0.69, n = 194). The reciprocal of the H+/CEC ratio is base saturation with Al added to the bases. Because of the low pH, exchangeable Al does not appear to behave as an acid. Exchangeable H+ remains an operationally defined quantity because of the difficulty in separating exchange and hydrolysis reactions. In a variety of neutral-salt extractants, concentration of H+ were correlated with 0.1 M BaCl2-exchangeable H+ (r > 0.91, P = 0.0001, n = 26) regardless of the strength of the extract. Nine successive extractions with 0.33 mM CaCl2 removed more H+ than was removed by single batch extractions with either 1 M KCl or 0.1 M BaCl2 (average H+ of 70, 43, and 49 mmol kg-1, respectively for 26 samples). The data showed little difference in the chemical behavior of Oa horizons from a variety of geographical sites and vegetation types.

  13. Dynamical symmetry enhancement near IIA horizons

    International Nuclear Information System (INIS)

    Gran, University; Gutowski, J.; Kayani, University; Papadopoulos, G.

    2015-01-01

    We show that smooth type IIA Killing horizons with compact spatial sections preserve an even number of supersymmetries, and that the symmetry algebra of horizons with non-trivial fluxes includes an sl(2,ℝ) subalgebra. This confirms the conjecture of http://dx.doi.org/10.1007/JHEP11(2013)104 for type IIA horizons. As an intermediate step in the proof, we also demonstrate new Lichnerowicz type theorems for spin bundle connections whose holonomy is contained in a general linear group.

  14. Instability of enclosed horizons

    Science.gov (United States)

    Kay, Bernard S.

    2015-03-01

    We point out that there are solutions to the scalar wave equation on dimensional Minkowski space with finite energy tails which, if they reflect off a uniformly accelerated mirror due to (say) Dirichlet boundary conditions on it, develop an infinite stress-energy tensor on the mirror's Rindler horizon. We also show that, in the presence of an image mirror in the opposite Rindler wedge, suitable compactly supported arbitrarily small initial data on a suitable initial surface will develop an arbitrarily large stress-energy scalar near where the two horizons cross. Also, while there is a regular Hartle-Hawking-Israel-like state for the quantum theory between these two mirrors, there are coherent states built on it for which there are similar singularities in the expectation value of the renormalized stress-energy tensor. We conjecture that in other situations with analogous enclosed horizons such as a (maximally extended) Schwarzschild black hole in equilibrium in a (stationary spherical) box or the (maximally extended) Schwarzschild-AdS spacetime, there will be similar stress-energy singularities and almost-singularities—leading to instability of the horizons when gravity is switched on and matter and gravity perturbations are allowed for. All this suggests it is incorrect to picture a black hole in equilibrium in a box or a Schwarzschild-AdS black hole as extending beyond the past and future horizons of a single Schwarzschild (/Schwarzschild-AdS) wedge. It would thus provide new evidence for 't Hooft's brick wall model while seeming to invalidate the picture in Maldacena's ` Eternal black holes in AdS'. It would thereby also support the validity of the author's matter-gravity entanglement hypothesis and of the paper ` Brick walls and AdS/CFT' by the author and Ortíz.

  15. Microbial chlorination of organic matter in forest soil: investigation using 36Cl-chloride and its methodology.

    Science.gov (United States)

    Rohlenová, J; Gryndler, M; Forczek, S T; Fuksová, K; Handova, V; Matucha, M

    2009-05-15

    Chloride, which comes into the forest ecosystem largely from the sea as aerosol (and has been in the past assumed to be inert), causes chlorination of soil organic matter. Studies of the chlorination showed that the content of organically bound chlorine in temperate forest soils is higher than that of chloride, and various chlorinated compounds are produced. Our study of chlorination of organic matter in the fermentation horizon of forest soil using radioisotope 36Cl and tracer techniques shows that microbial chlorination clearly prevails over abiotic, chlorination of soil organic matter being enzymatically mediated and proportional to chloride content and time. Long-term (>100 days) chlorination leads to more stable chlorinated substances contained in the organic layer of forest soil (overtime; chlorine is bound progressively more firmly in humic acids) and volatile organochlorines are formed. Penetration of chloride into microorganisms can be documented by the freezing/thawing technique. Chloride absorption in microorganisms in soil and in litter residues in the fermentation horizon complicates the analysis of 36Cl-chlorinated soil. The results show that the analytical procedure used should be tested for every soil type under study.

  16. Horizons of hermeneutics: Intercultural hermeneutics in a globalizing world

    NARCIS (Netherlands)

    J. de Mul (Jos)

    2011-01-01

    textabstractStarting from the often-used metaphor of the "horizon of experience" this article discusses three different types of intercultural hermeneutics, which respectively conceive hermeneutic interpretation as a widening of horizons, a fusion of horizons, and a dissemination of horizons. It is

  17. Impacts of Mastication: Soil Seed Bank Responses to a Forest Thinning Treatment in Three Colorado (USA Conifer Forest Types

    Directory of Open Access Journals (Sweden)

    Akasha M. Faist

    2015-08-01

    Full Text Available Mastication is a forest fuel thinning treatment that involves chipping or shredding small trees and shrubs and depositing the material across the forest floor. By decreasing forest density mastication has been shown to lessen crown fire hazard, yet other impacts have only recently started to be studied. Our study evaluates how mastication treatments alter the density and composition of soil seed banks in three Colorado conifer forest types. The three forest types were (1 lodgepole pine, (2 ponderosa pine and (3 pinyon pine-juniper. Results showed that masticated sites contained higher seed bank densities than untreated sites: a pattern primarily driven by treatment effects in ponderosa pine forests. The seed bank was dominated by forbs regardless of forest type or treatment. This pattern of forb dominance was not observed in the aboveground vegetation cover as it demonstrated more even proportions of the functional groups. Graminoids showed a higher seed density in treated sites than untreated and, similarly, the identified non-native species only occurred in the treated ponderosa pine sites suggesting a potential belowground invasion for this forest type. These results suggest that presence of masticated material might not be creating a physical barrier hindering the transfer of seeds as predicted.

  18. Building with electromagnetic shield structure for individual floors

    International Nuclear Information System (INIS)

    Takahashi, T.; Nakamura, M.; Yabana, Y.; Ishikawa, T.; Nagata, K.

    1991-01-01

    This invention relates to a building having a floor-by-floor electromagnetic shield structure well-suited for application to an information network system in which an electromagnetically shielded space is divided by individual floors and electric waves are utilized within the building on a floor-by-floor basis. (author). 8 figs

  19. Building with electromagnetic shield structure for individual floors

    Energy Technology Data Exchange (ETDEWEB)

    Takahashi, T; Nakamura, M; Yabana, Y; Ishikawa, T; Nagata, K

    1991-09-10

    This invention relates to a building having a floor-by-floor electromagnetic shield structure well-suited for application to an information network system in which an electromagnetically shielded space is divided by individual floors and electric waves are utilized within the building on a floor-by-floor basis. (author). 8 figs.

  20. Hawking radiation from quasilocal dynamical horizons

    Indian Academy of Sciences (India)

    2016-01-06

    Jan 6, 2016 ... Abstract. In completely local settings, we establish that a dynamically evolving spherically symmetric black hole horizon can be assigned a Hawking temperature and with the emission of flux, radius of the horizon shrinks.

  1. Across-horizon scattering and information transfer

    Science.gov (United States)

    Emelyanov, V. A.; Klinkhamer, F. R.

    2018-06-01

    We address the question whether or not two electrically charged elementary particles can Coulomb scatter if one of these particles is inside the Schwarzschild black-hole horizon and the other outside. It can be shown that the quantum process is consistent with the local energy–momentum conservation law. This result implies that across-horizon scattering is a physical effect, relevant to astrophysical black holes. We propose a Gedankenexperiment which uses the quantum scattering process to transfer information from inside the black-hole horizon to outside.

  2. Tropospheric radiowave propagation beyond the horizon

    CERN Document Server

    Du Castel, François

    1966-01-01

    Tropospheric Radiowave Propagation Beyond the Horizon deals with developments concerning the tropospheric propagation of ultra-short radio waves beyond the horizon, with emphasis on the relationship between the theoretical and the experimental. Topics covered include the general conditions of propagation in the troposphere; general characteristics of propagation beyond the horizon; and attenuation in propagation. This volume is comprised of six chapters and begins with a brief historical look at the various stages that have brought the technique of transhorizon links to its state of developmen

  3. Cellulose Dynamics during Foliar Litter Decomposition in an Alpine Forest Meta-Ecosystem

    Directory of Open Access Journals (Sweden)

    Kai Yue

    2016-08-01

    Full Text Available To investigate the dynamics and relative drivers of cellulose degradation during litter decomposition, a field experiment was conducted in three individual ecosystems (i.e., forest floor, stream, and riparian zone of an alpine forest meta-ecosystem on the eastern Tibetan Plateau. Four litter species (i.e., willow: Salix paraplesia, azalea: Rhododendron lapponicum, cypress: Sabina saltuaria, and larch: Larix mastersiana that had varying initial litter chemical traits were placed separately in litterbags and then incubated on the soil surface of forest floor plots or in the water of the stream and riparian zone plots. Litterbags were retrieved five times each year during the two-year experiment, with nine replicates each time for each treatment. The results suggested that foliar litter lost 32.2%–89.2% of the initial dry mass depending on litter species and ecosystem type after two-year’s incubation. The cellulose lost 60.1%–96.8% of the initial mass with degradation rate in the order of stream > riparian zone > forest floor. Substantial cellulose degradation occurred at the very beginning (i.e., in the first pre-freezing period of litter decomposition. Litter initial concentrations of phosphorus (P and lignin were found to be the dominant chemical traits controlling cellulose degradation regardless of ecosystems type. The local-scale environmental factors such as temperature, pH, and nutrient availability were important moderators of cellulose degradation rate. Although the effects of common litter chemical traits (e.g., P and lignin concentrations on cellulose degradation across different individual ecosystems were identified, local-scale environmental factors such as temperature and nutrient availability were found to be of great importance for cellulose degradation. These results indicated that local-scale environmental factors should be considered apart from litter quality for generating a reliable predictive framework for the drivers

  4. Change in Soil and Forest Floor Carbon after Shelterwood Harvests in a New England Oak-Hardwood Forest, USA

    Directory of Open Access Journals (Sweden)

    Kayanna L. Warren

    2014-01-01

    Full Text Available There has been effort worldwide to quantify how much carbon forests contain in order to designate appropriate offset credits to forest carbon climate mitigation. Carbon pools on or immediately below the soil surface are understood to be very active in response to environmental change but are not well understood. Our study focused on the effects of shelterwood regeneration harvests in New England on the carbon stored in litter, woody debris, and surface soil carbon. Results demonstrate significant difference in surface (0–10 cm soil carbon between control (nonharvested and harvested sites, with higher carbon percentage on control sites. Results showed a significant difference in coarse woody debris with higher amounts of carbon per area on harvested sites. No significant difference in litter mass was recorded between harvested and control sites. When coarse woody debris and litter are included with soil carbon, total carbon did not have a significant decline over 20 years following shelterwood treatment to the forest to secure regeneration, but there was considerable variability among sites. When taking all surface soil carbon measurements together, our results suggest that for accounting purposes the measurement of below-ground carbon after shelterwood harvests is not necessary for the southern New England region.

  5. Supply chain modeling of forest fuel

    Energy Technology Data Exchange (ETDEWEB)

    Gunnarsson, Helene; Lundgren, Jan T.; Roennqvist, Mikael

    2001-04-01

    We study the problem of deciding when and where forest residues are to be converted into forest fuel, and how the residues are to be transported and stored in order to satisfy demand at heating plants. Decisions also include whether or not additional harvest areas and saw-mills are to be contracted. In addition, we consider the flow of products from saw-mills and import harbors, and address the question about which terminals to use. The planning horizon is one year and monthly time periods are considered. The supply chain problem is formulated as a large mixed integer linear programming model. In order to obtain solutions within reasonable time we have developed a heuristic solution approach. Computational results from a large Swedish supplying entrepreneur are reported.

  6. Supply chain modeling of forest fuel

    International Nuclear Information System (INIS)

    Gunnarsson, Helene; Lundgren, Jan T.; Roennqvist, Mikael

    2001-04-01

    We study the problem of deciding when and where forest residues are to be converted into forest fuel, and how the residues are to be transported and stored in order to satisfy demand at heating plants. Decisions also include whether or not additional harvest areas and saw-mills are to be contracted. In addition, we consider the flow of products from saw-mills and import harbors, and address the question about which terminals to use. The planning horizon is one year and monthly time periods are considered. The supply chain problem is formulated as a large mixed integer linear programming model. In order to obtain solutions within reasonable time we have developed a heuristic solution approach. Computational results from a large Swedish supplying entrepreneur are reported

  7. First direct landscape-scale measurement of tropical rain forest Leaf Area Index, a key driver of global primary productivity

    Science.gov (United States)

    David B. Clark; Paulo C. Olivas; Steven F. Oberbauer; Deborah A. Clark; Michael G. Ryan

    2008-01-01

    Leaf Area Index (leaf area per unit ground area, LAI) is a key driver of forest productivity but has never previously been measured directly at the landscape scale in tropical rain forest (TRF). We used a modular tower and stratified random sampling to harvest all foliage from forest floor to canopy top in 55 vertical transects (4.6 m2) across 500 ha of old growth in...

  8. Mastering VMware Horizon 6

    CERN Document Server

    Oven, Peter von

    2015-01-01

    If you are working as a desktop admin, part of a EUC team, an architect, or a consultant on a desktop virtualization project and you are looking to use VMware's Horizon solution, this book is for you. This book will demonstrate the new capabilities of Horizon 6. You should have experience in desktop management using Windows and Microsoft Office, and be familiar with Active Directory, SQL, Windows Remote Desktop Session Hosting, and VMware vSphere infrastructure (ESXi and vCenter Server) technology.

  9. Horizon 2020 in sight

    CERN Multimedia

    Joannah Caborn Wengler

    2012-01-01

    Every tenth member of the CERN personnel participates in an EU-funded project – a strong indication of CERN’s successful relations with the European Commission (EC), coordinated by the CERN EU projects office. The EC director in charge of preparing “Horizon 2020”, the new EU funding programme for research and innovation (2014-2020), will be giving a presentation at CERN on 8 May. He will reveal more about what the new programme has in store.   “It’s a very interesting time in the development of Horizon 2020, which is focusing the attention of all research communities in Europe,” explains Svetlomir Stavrev, head of the EU projects office. “After a long public consultation and drafting process, the Horizon 2020 proposal documents are now being reviewed by the European Parliament and Council.” CERN already participated in the consultation, making good use of the opportunity to contribute to the shaping of wh...

  10. Implementing VMware Horizon View 5.2

    CERN Document Server

    Ventresco, Jason

    2013-01-01

    A step-by-step tutorial covering all components of the View Horizon suite in detail, to ensure that you can utilize all features of the platform, and discover all of the possible ways that it can be used within your own environment.If you are a newcomer in system administration, and you wish to implement a small to midsized Horizon View environment, then this book is for you. It will also benefit individuals who wish to administrate and manage Horizon View more efficiently or are studying for the VCP5-DT.

  11. Soil water storage and groundwater behaviour in a catenary sequence beneath forest in central Amazonia: I. Comparisons between plateau, slope and valley floor

    Directory of Open Access Journals (Sweden)

    M. G. Hodnett

    1997-01-01

    Full Text Available Soil water storage was monitored in three landscape elements in the forest (plateau, slope and valley floor over a 3 year period to identify differences in sub-surface hydrological response. Under the plateau and slope, the changes of storage were very similar and there was no indication of surface runoff on the slope. The mean maximum seasonal storage change was 156 mm in the 2 m profile but it was clear that, in the dry season, the forest was able to take up water from below 3.6 m. Soil water availability was low. Soil water storage changes in the valley were dominated by the behaviour of a shallow water table which, in normal years, varied between 0.1 m below the surface at the end of the wet season and 0.8 m at the end of the dry season. Soil water storage changes were small because root uptake was largely replenished by groundwater flow towards the stream. The groundwater behaviour is controlled mainly by the deep drainage from beneath the plateau and slope areas. The groundwater gradient beneath the slope indicated that recharge beneath the plateau and slope commences only after the soil water deficits from the previous dry season have been replenished. Following a wet season with little recharge, the water table fell, ceasing to influence the valley soil water storage, and the stream dried up. The plateau and slope, a zone of very high porosity between 0.4 and 1.1 m, underlain by a less conductive layer, is a probable route for interflow during, and for a few hours after, heavy and prolonged rainfall.

  12. Vine maple (Acer circinatum) clone growth and reproduction in managed and unmanaged coastal Oregon douglas-fir forests

    Science.gov (United States)

    O'Dea, Mary E.; Zasada, John C.; Tappeiner, John C.

    1995-01-01

    Vine maple (Acer circinatum Pursh.) clone development, expansion, and regeneration by seedling establishment were studied in 5-240 yr old managed and unmanaged Douglas-fir (Pseudotsuga menziesii (Mirb.) Franco) stands in coastal Oregon. Stem length, number of stems, and crown area were all significantly (P @10 m long and basal sprouts 1-2 m long; some stems had been pinned to the forest floor by fallen trees or branches and had layered. In stands >120 yr in age, clones were often quite complex, composed of several decumbent stems each of which connected the ramets of 1-10 new aerial stems. Vine maple clone expansion occurs by the layering of long aerial stems. Over 95% of the layered stems we observed had been pinned to the forest floor by fallen debris. Unsevered stems that we artificially pinned to the forest floor initiated roots within 1 yr. Thinning may favor clonal expansion because fallen slash from thinning often causes entire clones to layer, not just individual stems. Clonal vine maple seed production and seedling establishment occurred in all stages of stand development except dense, young stands following crown closure. There were more seedlings in thinned stands than in unthinned stands and in unburned clearcuts than in burned clearcuts.

  13. Carbon storage in Ontario's forests, 2000-2100

    International Nuclear Information System (INIS)

    Colombo, S.J.; Chen, J.; Ter-Mikaelian, M.T.

    2007-01-01

    One of the greatest challenges facing modern society is rapid climate change resulting from greenhouse gases emissions to the atmosphere, primarily in the form of carbon dioxide from the burning of fossil fuels. The effects of climate change on natural environments will inevitably affect people as well, if left unchanged. In addition to many other societal benefits, forests store large amounts of carbon. As a result, it is necessary to understand how forest management and natural processes affect forest carbon storage. Such information can be utilized to manage forests so that they function as carbon sinks and help reduce greenhouse gas concentrations in the atmosphere. This report employed data about Ontario's forest structure and information from the forest management planning process and past harvests to describe carbon in forests and wood products today and through to the end of this century. The paper described the methods used for the study which included modification of the United States national forest carbon model, FORCARB2, to predict Ontario's forest carbon budgets in order to make carbon projections congruent with forest management plans. The modified forest carbon model, which is called FORCARB-ON, predicts carbon in live trees, understory vegetation, forest floor, standing and down dead wood, and soil. Ontario's managed forests are projected to increase carbon storage by 433 million tonnes from 2000 to 2100. The largest forest sink will be in wood products, accounting for 364 million tonnes of carbon storage over the century. 22 refs., 1 tab., 3 figs

  14. Classification of Near-Horizon Geometries of Extremal Black Holes

    Directory of Open Access Journals (Sweden)

    Hari K. Kunduri

    2013-09-01

    Full Text Available Any spacetime containing a degenerate Killing horizon, such as an extremal black hole, possesses a well-defined notion of a near-horizon geometry. We review such near-horizon geometry solutions in a variety of dimensions and theories in a unified manner. We discuss various general results including horizon topology and near-horizon symmetry enhancement. We also discuss the status of the classification of near-horizon geometries in theories ranging from vacuum gravity to Einstein–Maxwell theory and supergravity theories. Finally, we discuss applications to the classification of extremal black holes and various related topics. Several new results are presented and open problems are highlighted throughout.

  15. Classification of Near-Horizon Geometries of Extremal Black Holes.

    Science.gov (United States)

    Kunduri, Hari K; Lucietti, James

    2013-01-01

    Any spacetime containing a degenerate Killing horizon, such as an extremal black hole, possesses a well-defined notion of a near-horizon geometry. We review such near-horizon geometry solutions in a variety of dimensions and theories in a unified manner. We discuss various general results including horizon topology and near-horizon symmetry enhancement. We also discuss the status of the classification of near-horizon geometries in theories ranging from vacuum gravity to Einstein-Maxwell theory and supergravity theories. Finally, we discuss applications to the classification of extremal black holes and various related topics. Several new results are presented and open problems are highlighted throughout.

  16. Exotic Earthworms Decrease Cd, Hg, and Pb Pools in Upland Forest Soils of Vermont and New Hampshire USA.

    Science.gov (United States)

    Richardson, J B; Görres, J H; Friedland, A J

    2017-10-01

    Exotic earthworms are present in the forests of northeastern USA, yet few studies have documented their effects on pollutant metals in soil. The objective of this study was to identify if Cd, Hg, and Pb strong-acid extractable concentrations and pools (bulk inventories) in forest soils decreased with the presence of exotic earthworms. We compared 'Low Earthworm Abundance' (LEA) sites (≤10 g m -2 earthworms, n = 13) and 'High Earthworm Abundance' (HEA) (>10 g m -2 earthworms, n = 17) sites at five watersheds across Vermont and New Hampshire. Organic horizon Cd, Hg, and Pb concentrations were lower at HEA than LEA sites. Organic horizon and total soil pools of Cd and Hg were negatively correlated with earthworm biomass. Soil profile Cd and Hg concentrations were lower at HEA than LEA sites. Our results suggest earthworms are decreasing accumulation of Cd, Hg, and Pb in forest soils, potentially via greater mobilization through organic matter disruption or bioaccumulation.

  17. Moving Horizon Estimation and Control

    DEFF Research Database (Denmark)

    Jørgensen, John Bagterp

    successful and applied methodology beyond PID-control for control of industrial processes. The main contribution of this thesis is introduction and definition of the extended linear quadratic optimal control problem for solution of numerical problems arising in moving horizon estimation and control...... problems. Chapter 1 motivates moving horizon estimation and control as a paradigm for control of industrial processes. It introduces the extended linear quadratic control problem and discusses its central role in moving horizon estimation and control. Introduction, application and efficient solution....... It provides an algorithm for computation of the maximal output admissible set for linear model predictive control. Appendix D provides results concerning linear regression. Appendix E discuss prediction error methods for identification of linear models tailored for model predictive control....

  18. Effects of prescribed fire intervals on carbon and nitrogen in forest soils of the Mogollon Rim, Arizona

    Science.gov (United States)

    Daniel G. Neary; Steven T. Overby; Sally M. Haase

    2003-01-01

    The pre-European settlement ponderosa pine forests of the Mogollon Rim consisted of open stands of uneven-aged trees with a significant grass-forb understory. Light surface-fires occurred on an average interval of 2 to 12 years in Arizona and New Mexico (Dietrich 1980). These fires consumed forest floor material, burned most of the young regeneration, and promoted...

  19. Flooring choices for newborn ICUs.

    Science.gov (United States)

    White, R D

    2007-12-01

    Floors are a major element of newborn intensive care unit (NICU) construction. They provide visual cues, sound control, and with certain materials, some degree of physical comfort for workers. Flooring materials may entail a significant cost for installation and upkeep and can have substantial ecological impact, both in the choice of the flooring itself, as well as the substances used to clean it. In this article the important aspects to consider for each factor are explored and recommendations are offered for appropriate choices in various NICU areas.

  20. VARIABILITY OF ARABLE AND FOREST SOILS PROPERTIES ON ERODED SLOPES

    Directory of Open Access Journals (Sweden)

    Paweł Wiśniewski

    2014-10-01

    Full Text Available The basic method of reducing soil and land erosion is a change of land use, for example, from arable to forest. Particularly effective as a protective role – according to the Polish law – soil-protecting forests. The thesis presents differences in the deformation of the basic soil properties on moraine slopes, depending on land use. There has been presented the function and the efficiency of the soil-protecting forests in erosion control. The soil cross section transects and soil analysis displayed that soil-protecting forests are making an essential soil cover protection from degradation, inter alia, limiting the decrease of humus content, reduction of upper soil horizons and soil pedons layer. On the afforested slopes it was stated some clear changes of grain size and chemical properties of soils in relation to adjacent slopes agriculturally used.

  1. The natural abundance of 15N in litter and soil profiles under six temperate tree species: N cycling depends on tree species traits and site fertility

    DEFF Research Database (Denmark)

    Callesen, Ingeborg; Nilsson, Lars Ola; Schmidt, Inger Kappel

    2013-01-01

    We investigated the influence of tree species on the natural 15N abundance in forest stands under elevated ambient N deposition.We analysed δ15N in litter, the forest floor and three mineral soil horizons along with ecosystem N status variables at six sites planted three decades ago with five Eur...... to nitrate leaching or other N transformation processes....... species leached more nitrate.The δ15N pattern reflected tree species related traits affecting the N cycling as well as site fertility and former land use, and possibly differences in N leaching. The tree species δ15N patterns reflected fractionation caused by uptake of N through mycorrhiza rather than due...

  2. Comparison of the composition of forest soil litter derived from three different sites at various decompositional stages using FTIR spectroscopy

    International Nuclear Information System (INIS)

    Haberhauer, G.; Rafferty, B.; Strebl, F.; Gerzabek, M. H.

    1998-06-01

    Transmission Fourier transformed infrared spectroscopy was used to compare organic soil layers originating from three different sites in two climatic regions. A variety of bands characteristic of molecular structures and functional groups have been identified for these samples from a humic podsol, a dystric cambisol and a spodo dystric cambisol. Similar results were obtained for all three soils. From L to H soil horizons, an increase of the band at 1630 cm -1 and decrease of bands in the region from 1510 cm -1 to 1230 cm -1 were observed. The band at 1630 cm -1 can be assigned to carboxylic and aromatic groups. The decline of the peak intensity at 1510 cm -1 is significantly correlated to the total carbon content and C/N ratio. The mineral material of the Ah horizons leads to an increase of the band at 1050 cm -1 due to IR-absorbance of the Si-O bond and to an appearance of bands in the region from 900 to 400 cm -1 , which are characteristic for clay and quartz minerals. Analysis of the FTIR absorbance showed that intensities of distinct peaks (e.g., at 1510 cm -1 ) can be a measure of decomposition of forest litter. Therefore, the proposed simple FTIR method has potential for identification and differentiation of organic soil horizons originating from known tree litter. The similarity of the characteristics of the spectra of the three soil profiles investigated suggests a broad applicability of this method to distinguish organic forest soil horizons. On the basis of the data presented in this study, it may be concluded that FTIR spectroscopy offers a simple, powerful, non-destructive tool for the investigation of decomposition of L to H horizons in forest soils. (author)

  3. Manganese in the litter fall-forest floor continuum of boreal and temperate pine and spruce forest ecosystems

    DEFF Research Database (Denmark)

    Berg, Björn; Erhagen, Björn; Johansson, Maj-Britt

    2015-01-01

    We have reviewed the literature on the role of manganese (Mn) in the litter fall-to-humus subsystem. Available data gives a focus on North European coniferous forests. Manganese concentrations in pine (Pinus spp.) foliar litter are highly variable both spatially and temporally within the same lit...

  4. Simulations of floor cooling system capacity

    International Nuclear Information System (INIS)

    Odyjas, Andrzej; Górka, Andrzej

    2013-01-01

    Floor cooling system capacity depends on its physical and operative parameters. Using numerical simulations, it appears that cooling capacity of the system largely depends on the type of cooling loads occurring in the room. In the case of convective cooling loads capacity of the system is small. However, when radiation flux falls directly on the floor the system significantly increases productivity. The article describes the results of numerical simulations which allow to determine system capacity in steady thermal conditions, depending on the type of physical parameters of the system and the type of cooling load occurring in the room. Moreover, the paper sets out the limits of system capacity while maintaining a minimum temperature of the floor surface equal to 20 °C. The results are helpful for designing system capacity in different type of cooling loads and show maximum system capacity in acceptable thermal comfort condition. -- Highlights: ► We have developed numerical model for simulation of floor cooling system. ► We have described floor system capacity depending on its physical parameters. ► We have described floor system capacity depending on type of cooling loads. ► The most important in the obtained cooling capacities is the type of cooling loads. ► The paper sets out the possible maximum cooling floor system capacity

  5. Understory Plant Community Composition Is Associated with Fine-Scale Above- and Below-Ground Resource Heterogeneity in Mature Lodgepole Pine (Pinus contorta) Forests

    Science.gov (United States)

    McIntosh, Anne C. S.; Macdonald, S. Ellen; Quideau, Sylvie A.

    2016-01-01

    Understory plant communities play critical ecological roles in forest ecosystems. Both above- and below-ground ecosystem properties and processes influence these communities but relatively little is known about such effects at fine (i.e., one to several meters within-stand) scales, particularly for forests in which the canopy is dominated by a single species. An improved understanding of these effects is critical for understanding how understory biodiversity is regulated in such forests and for anticipating impacts of changing disturbance regimes. Our primary objective was to examine the patterns of fine-scale variation in understory plant communities and their relationships to above- and below-ground resource and environmental heterogeneity within mature lodgepole pine forests. We assessed composition and diversity of understory vegetation in relation to heterogeneity of both the above-ground (canopy tree density, canopy and tall shrub basal area and cover, downed wood biomass, litter cover) and below-ground (soil nutrient availability, decomposition, forest floor thickness, pH, and phospholipid fatty acids (PLFAs) and multiple carbon-source substrate-induced respiration (MSIR) of the forest floor microbial community) environment. There was notable variation in fine-scale plant community composition; cluster and indicator species analyses of the 24 most commonly occurring understory species distinguished four assemblages, one for which a pioneer forb species had the highest cover levels, and three others that were characterized by different bryophyte species having the highest cover. Constrained ordination (distance-based redundancy analysis) showed that two above-ground (mean tree diameter, litter cover) and eight below-ground (forest floor pH, plant available boron, microbial community composition and function as indicated by MSIR and PLFAs) properties were associated with variation in understory plant community composition. These results provide novel insights

  6. Understory Plant Community Composition Is Associated with Fine-Scale Above- and Below-Ground Resource Heterogeneity in Mature Lodgepole Pine (Pinus contorta Forests.

    Directory of Open Access Journals (Sweden)

    Anne C S McIntosh

    Full Text Available Understory plant communities play critical ecological roles in forest ecosystems. Both above- and below-ground ecosystem properties and processes influence these communities but relatively little is known about such effects at fine (i.e., one to several meters within-stand scales, particularly for forests in which the canopy is dominated by a single species. An improved understanding of these effects is critical for understanding how understory biodiversity is regulated in such forests and for anticipating impacts of changing disturbance regimes. Our primary objective was to examine the patterns of fine-scale variation in understory plant communities and their relationships to above- and below-ground resource and environmental heterogeneity within mature lodgepole pine forests. We assessed composition and diversity of understory vegetation in relation to heterogeneity of both the above-ground (canopy tree density, canopy and tall shrub basal area and cover, downed wood biomass, litter cover and below-ground (soil nutrient availability, decomposition, forest floor thickness, pH, and phospholipid fatty acids (PLFAs and multiple carbon-source substrate-induced respiration (MSIR of the forest floor microbial community environment. There was notable variation in fine-scale plant community composition; cluster and indicator species analyses of the 24 most commonly occurring understory species distinguished four assemblages, one for which a pioneer forb species had the highest cover levels, and three others that were characterized by different bryophyte species having the highest cover. Constrained ordination (distance-based redundancy analysis showed that two above-ground (mean tree diameter, litter cover and eight below-ground (forest floor pH, plant available boron, microbial community composition and function as indicated by MSIR and PLFAs properties were associated with variation in understory plant community composition. These results provide

  7. Understory Plant Community Composition Is Associated with Fine-Scale Above- and Below-Ground Resource Heterogeneity in Mature Lodgepole Pine (Pinus contorta) Forests.

    Science.gov (United States)

    McIntosh, Anne C S; Macdonald, S Ellen; Quideau, Sylvie A

    2016-01-01

    Understory plant communities play critical ecological roles in forest ecosystems. Both above- and below-ground ecosystem properties and processes influence these communities but relatively little is known about such effects at fine (i.e., one to several meters within-stand) scales, particularly for forests in which the canopy is dominated by a single species. An improved understanding of these effects is critical for understanding how understory biodiversity is regulated in such forests and for anticipating impacts of changing disturbance regimes. Our primary objective was to examine the patterns of fine-scale variation in understory plant communities and their relationships to above- and below-ground resource and environmental heterogeneity within mature lodgepole pine forests. We assessed composition and diversity of understory vegetation in relation to heterogeneity of both the above-ground (canopy tree density, canopy and tall shrub basal area and cover, downed wood biomass, litter cover) and below-ground (soil nutrient availability, decomposition, forest floor thickness, pH, and phospholipid fatty acids (PLFAs) and multiple carbon-source substrate-induced respiration (MSIR) of the forest floor microbial community) environment. There was notable variation in fine-scale plant community composition; cluster and indicator species analyses of the 24 most commonly occurring understory species distinguished four assemblages, one for which a pioneer forb species had the highest cover levels, and three others that were characterized by different bryophyte species having the highest cover. Constrained ordination (distance-based redundancy analysis) showed that two above-ground (mean tree diameter, litter cover) and eight below-ground (forest floor pH, plant available boron, microbial community composition and function as indicated by MSIR and PLFAs) properties were associated with variation in understory plant community composition. These results provide novel insights

  8. Formaldehyde and TVOC emission behavior of laminate flooring by structure of laminate flooring and heating condition.

    Science.gov (United States)

    An, Jae-Yoon; Kim, Sumin; Kim, Hyun-Joong

    2011-03-15

    Formaldehyde was measured with a desiccator, a 20 L chamber and the FLEC method. The formaldehyde emission rate from laminate was the highest at 32 °C using the desiccator, which then decreased with time. The formaldehyde emission using the 20 L small chamber and FLEC showed a similar tendency. There was a strong correlation between the formaldehyde and total volatile organic compounds (TVOCs) with both types of floorings using the two different methods. The formaldehyde emission rate and TVOC results were higher when tested using the FLEC method than with the 20 L small chamber method. The emission rate was affected by the joint edge length in laminate flooring. Toluene, ethylbenzene and xylene were the main VOCs emitted from laminate flooring, and there were more unidentified VOCs emitted than identified VOCs. The samples heated with a floor heating system emitted more formaldehyde than those heated using an air circulation system due to the temperature difference between the bottom panel and flooring. The TVOC emission level of the samples was higher when an air circulation system was used than when a floor heating system was used due to the high ventilation rate. Copyright © 2010 Elsevier B.V. All rights reserved.

  9. Stretched horizons, quasiparticles, and quasinormal modes

    International Nuclear Information System (INIS)

    Iizuka, Norihiro; Kabat, Daniel; Lifschytz, Gilad; Lowe, David A.

    2003-01-01

    We propose that stretched horizons can be described in terms of a gas of noninteracting quasiparticles. The quasiparticles are unstable, with a lifetime set by the imaginary part of the lowest quasinormal mode frequency. If the horizon arises from an AdS-CFT style duality the quasiparticles are also the effective low-energy degrees of freedom of the finite-temperature CFT. We analyze a large class of models including Schwarzschild black holes, nonextremal Dp-branes, the rotating BTZ black hole and de Sitter space, and we comment on degenerate horizons. The quasiparticle description makes manifest the relationship between entropy and area

  10. Gross changes in forest area shape the future carbon balance of tropical forests

    Science.gov (United States)

    Li, Wei; Ciais, Philippe; Yue, Chao; Gasser, Thomas; Peng, Shushi; Bastos, Ana

    2018-01-01

    Bookkeeping models are used to estimate land-use and land-cover change (LULCC) carbon fluxes (ELULCC). The uncertainty of bookkeeping models partly arises from data used to define response curves (usually from local data) and their representativeness for application to large regions. Here, we compare biomass recovery curves derived from a recent synthesis of secondary forest plots in Latin America by Poorter et al. (2016) with the curves used previously in bookkeeping models from Houghton (1999) and Hansis et al. (2015). We find that the two latter models overestimate the long-term (100 years) vegetation carbon density of secondary forest by about 25 %. We also use idealized LULCC scenarios combined with these three different response curves to demonstrate the importance of considering gross forest area changes instead of net forest area changes for estimating regional ELULCC. In the illustrative case of a net gain in forest area composed of a large gross loss and a large gross gain occurring during a single year, the initial gross loss has an important legacy effect on ELULCC so that the system can be a net source of CO2 to the atmosphere long after the initial forest area change. We show the existence of critical values of the ratio of gross area change over net area change (γAnetAgross), above which cumulative ELULCC is a net CO2 source rather than a sink for a given time horizon after the initial perturbation. These theoretical critical ratio values derived from simulations of a bookkeeping model are compared with observations from the 30 m resolution Landsat Thematic Mapper data of gross and net forest area change in the Amazon. This allows us to diagnose areas in which current forest gains with a large land turnover will still result in LULCC carbon emissions in 20, 50 and 100 years.

  11. Stereo photo series for quantifying natural fuels. Volume XII: Post-hurricane fuels in forests of the Southeast United States.

    Science.gov (United States)

    Robert E. Vihnanek; Cameron S. Balog; Clinton S. Wright; Roger D. Ottmar; Jeffrey W. Kelly

    2009-01-01

    Two series of single and stereo photographs display a range of natural conditions and fuel loadings in post-hurricane forests in the southeastern United States. Each group of photos includes inventory information summarizing vegetation composition, structure and loading, woody material loading and density by size class, forest floor loading, and various site...

  12. Crustal Ages of the Ocean Floor - Poster

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The Crustal Ages of the Ocean Floor Poster was created at NGDC using the Crustal Ages of the Ocean Floor database draped digitally over a relief of the ocean floor...

  13. Does the precipitation redistribution of the canopy sense in the moisture pattern of the forest litter?

    Science.gov (United States)

    Zagyvai-Kiss, Katalin Anita; Kalicz, Péter; Csáfordi, Péter; Kucsara, Mihály; Gribovszki, Zoltán

    2013-04-01

    Precipitation is trapped and temporarily stored by the surfaces of forest crown (canopy interception) and forest litter (litter interception). The stemflow and throughfall reach the litter, thus theoretically the litter moisture content depends on these parts of precipitation. Nowadays the moisture pattern of the forest floor, both spatial and temporal scale, have growing respect for the forestry. The transition to the continuous cover forestry induce much higher variability compared to the even aged, more-less homogeneous, monocultural stands. The gap cutting is one of the key methods in the Hungarian forestry. There is an active discussion among the forest professionals how to determine the optimal gap size to maintain the optimal conditions for the seedlings. Among the open questions is how to modify surrounding trees the moisture pattern of the forest floor in the gap? In the early steps of a multidisciplinary project we processed some available data, to estimate the spatial dependency between the water content of forest litter and the spatial pattern of the canopy represented by the tree trunk. The maximum water content depends on dry weight of litter, thus we also analysed that parameter. Data were measured in three different forest ecosystems: a middle age beech (Fagus sylvatica), a sessile oak (Quercus petraea) and a spruce (Picea abies) stand. The study site (Hidegvíz Valley Research Cathcment) is located in Sopron Hills at the eastern border of the Alps. Litter samples were collected under each stand (occasionally 10-10 pieces from 40?40 cm area) and locations of the samples and neighbouring trees were mapped. We determined dry weight and the water content of litter in laboratory. The relationship between water content and the distance of tree trunks in case of spruce and oak stands were not significant and in case of the beech stand was weakly significant. Climate change effects can influence significantly forest floor moisture content, therefore this

  14. Calcium mineralization in the forest floor and surface soil beneath different tree species in the northeastern US

    NARCIS (Netherlands)

    Dijkstra, F.A.

    2003-01-01

    Calcium (Ca) is an important element for neutralizing soil acidity in temperate forests. The immediate availability of Ca in forested acid soils is largely dependent on mineralization of organic Ca, which may differ significantly among tree species. I estimated net Ca mineralization in the forest

  15. Carbon storage in old-growth forests of the Mid-Atlantic: toward better understanding the eastern forest carbon sink.

    Science.gov (United States)

    McGarvey, Jennifer C; Thompson, Jonathan R; Epstein, Howard E; Shugart, Herman H

    2015-02-01

    Few old-growth stands remain in the matrix of secondary forests that dominates the eastern North American landscape. These remnant stands offer insight on the potential carbon (C) storage capacity of now-recovering secondary forests. We surveyed the remaining old-growth forests on sites characteristic of the general Mid-Atlantic United States and estimated the size of multiple components of forest C storage. Within and between old-growth stands, variability in C density is high and related to overstory tree species composition. The sites contain 219 ± 46 Mg C/ha (mean ± SD), including live and dead aboveground biomass, leaf litter, and the soil O horizon, with over 20% stored in downed wood and snags. Stands dominated by tulip poplar (Liriodendron tulipifera) store the most live biomass, while the mixed oak (Quercus spp.) stands overall store more dead wood. Total C density is 30% higher (154 Mg C/ha), and dead wood C density is 1800% higher (46 Mg C/ha) in the old-growth forests than in the surrounding younger forests (120 and 5 Mg C/ha, respectively). The high density of dead wood in old growth relative to secondary forests reflects a stark difference in historical land use and, possibly, the legacy of the local disturbance (e.g., disease) history. Our results demonstrate the potential for dead wood to maintain the sink capacity of secondary forests for many decades to come.

  16. Nonlinear optics of fibre event horizons.

    Science.gov (United States)

    Webb, Karen E; Erkintalo, Miro; Xu, Yiqing; Broderick, Neil G R; Dudley, John M; Genty, Goëry; Murdoch, Stuart G

    2014-09-17

    The nonlinear interaction of light in an optical fibre can mimic the physics at an event horizon. This analogue arises when a weak probe wave is unable to pass through an intense soliton, despite propagating at a different velocity. To date, these dynamics have been described in the time domain in terms of a soliton-induced refractive index barrier that modifies the velocity of the probe. Here we complete the physical description of fibre-optic event horizons by presenting a full frequency-domain description in terms of cascaded four-wave mixing between discrete single-frequency fields, and experimentally demonstrate signature frequency shifts using continuous wave lasers. Our description is confirmed by the remarkable agreement with experiments performed in the continuum limit, reached using ultrafast lasers. We anticipate that clarifying the description of fibre event horizons will significantly impact on the description of horizon dynamics and soliton interactions in photonics and other systems.

  17. Black holes or firewalls: A theory of horizons

    Science.gov (United States)

    Nomura, Yasunori; Varela, Jaime; Weinberg, Sean J.

    2013-10-01

    We present a quantum theory of black hole (and other) horizons, in which the standard assumptions of complementarity are preserved without contradicting information theoretic considerations. After the scrambling time, the quantum mechanical structure of a black hole becomes that of an eternal black hole at the microscopic level. In particular, the stretched horizon degrees of freedom and the states entangled with them can be mapped into the near-horizon modes in the two exterior regions of an eternal black hole, whose mass is taken to be that of the evolving black hole at each moment. Salient features arising from this picture include (i) the number of degrees of freedom needed to describe a black hole is eA/2lP2, where A is the area of the horizon; (ii) black hole states having smooth horizons, however, span only an eA/4lP2-dimensional subspace of the relevant eA/2lP2-dimensional Hilbert space; (iii) internal dynamics of the horizon is such that an infalling observer finds a smooth horizon with a probability of 1 if a state stays in this subspace. We identify the structure of local operators responsible for describing semiclassical physics in the exterior and interior spacetime regions and show that this structure avoids the arguments for firewalls—the horizon can keep being smooth throughout the evolution. We discuss the fate of infalling observers under various circumstances, especially when the observers manipulate degrees of freedom before entering the horizon, and we find that an observer can never see a firewall by making a measurement on early Hawking radiation. We also consider the presented framework from the viewpoint of an infalling reference frame and argue that Minkowski-like vacua are not unique. In particular, the number of true Minkowski vacua is infinite, although the label discriminating these vacua cannot be accessed in usual nongravitational quantum field theory. An application of the framework to de Sitter horizons is also discussed.

  18. Radiocesium accumulation in the anuran frog, Rana tagoi tagoi, in forest ecosystems after the Fukushima Nuclear Power Plant accident

    International Nuclear Information System (INIS)

    Takahara, Teruhiko; Endo, Satoru; Takada, Momo; Oba, Yurika; Nursal, Wim Ikbal; Igawa, Takeshi; Doi, Hideyuki; Yamada, Toshihiro; Okuda, Toshinori

    2015-01-01

    Amphibians are key components in forest food webs. When examining radioactive contamination in anurans, it is important to understand how radiocesium transfer occurs from lower to higher trophic levels in forest ecosystems. We investigated the activity concentration of radiocesium ( 134 Cs and 137 Cs) in Tago's brown frog (Rana tagoi tagoi) captured on the forest floor approximately 2.5 years after the Fukushima Nuclear Power Plant (FNPP) accident. We collected 66 R. tagoi tagoi at different distances from the FNPP. Radiocesium accumulation showed positive correlations with the air radiation dose rate and litter contamination but not with distance from the FNPP. Whole-body radioactivity showed no correlation with body mass or length. Our results suggest that differences in the available food items result in large variability in individual contamination. Contamination level monitoring in terrestrial and aquatic amphibian is necessary for clarifying the processes and mechanisms of radiocesium transfer through forest food webs. - Highlights: • Radiocesium level in Rana tagoi tagoi from forests near Fukushima was assessed. • Radiocesium accumulation was related to air dose rate and litter contamination. • Differences in dietary intake might lead to variability in individual contamination. • Transfer of radiocesium among trophic levels can occur via anurans. - Rana tagoi tagoi accumulates radiocesium in forest floor habitats near Fukushima

  19. 75 FR 66126 - Multilayered Wood Flooring From China

    Science.gov (United States)

    2010-10-27

    ...)] Multilayered Wood Flooring From China AGENCY: United States International Trade Commission. ACTION: Institution... flooring, provided for in subheadings 4409.10, 4409.29, 4412.31, 4412.32, 4412.39, 4412.94, 4412.99, 4418... multilayered wood flooring. The following companies are members of the CAHP: Anderson Hardwood Floors, LLC...

  20. 75 FR 79019 - Multilayered Wood Flooring From China

    Science.gov (United States)

    2010-12-17

    ...)] Multilayered Wood Flooring From China Determinations On the basis of the record \\1\\ developed in the subject... imports from China of multilayered wood flooring, provided for in subheadings 4409.10, 4409.29, 4412.31... multilayered wood flooring. The following companies are members of the CAHP: Anderson Hardwood Floors, LLC...

  1. Mode of delivery and Pelvic floor disorder

    International Nuclear Information System (INIS)

    Noor, R.; Neelam, H.; Bashir, M.S.

    2017-01-01

    Objective: To compare pelvic floor dysfunction in non pregnant women who had delivered vaginally versus those with cesarean delivery. Methodology: The prevalence of pelvic floor disorders among non pregnant women was assesses by using a standardized tool pelvic floor distress inventory short form (PFDI-20). Data was collected from Jinnah Hospital Lahore, Pakistan. Results: Total numbers of participants were 278. 47.12% subjects had moderate, 36.69% miner and 16.19% had severe pelvic floor dysfunction. The symptoms of pelvic organ prolapse were more prevalent (mean value is 59.1876) than Urinary Distress (mean value is 40.5426), while the Colorectal-Anal Distress (mean value is 35.9150) were least prevalent. Conclusion: Pelvic floor disorders are very common among females and are strongly associated with mode of delivery. Although spontaneous vaginal birth was extensively associated with pelvic floor disorders the instrumental delivery affects most. (author)

  2. Functional anatomy of pelvic floor

    Directory of Open Access Journals (Sweden)

    Salvatore Rocca Rossetti

    2016-03-01

    Full Text Available Generally, descriptions of the pelvic floor are discordant, since its complex structures and the complexity of pathological disorders of such structures; commonly the descriptions are sectorial, concerning muscles, fascial developments, ligaments and so on. On the contrary to understand completely nature and function of the pelvic floor it is necessary to study it in the most unitary view and in the most global aspect, considering embriology, philogenesy, anthropologic development and its multiple activities others than urological, gynaecological and intestinal ones. Recent acquirements succeeded in clarifying many aspects of pelvic floor activity, whose musculature has been investigated through electromyography, sonography, magnetic resonance, histology, histochemistry, molecular research. Utilizing recent research concerning not only urinary and gynecologic aspects but also those regarding statics and dynamics of pelvis and its floor, it is now possible to study this important body part as a unit; that means to consider it in the whole body economy to which maintaining upright position, walking and behavior or physical conduct do not share less than urinary, genital, and intestinal functions. It is today possible to consider the pelvic floor as a musclefascial unit with synergic and antagonistic activity of muscular bundles, among them more or less interlaced, with multiple functions and not only the function of pelvic cup closure.

  3. Estimation of radioactive 137-cesium transportation by litterfall, stemflow and throughfall in the forests of Fukushima

    International Nuclear Information System (INIS)

    Endo, Izuki; Ohte, Nobuhito; Iseda, Kohei; Tanoi, Keitaro; Hirose, Atsushi; Kobayashi, Natsuko I.; Murakami, Masashi; Tokuchi, Naoko; Ohashi, Mizue

    2015-01-01

    Since the Fukushima Dai-ichi Nuclear Power Plant accident in March 2011, large areas of the forests around Fukushima have become highly contaminated by radioactive nuclides. To predict the future dynamics of radioactive cesium ( 137 Cs) in the forest catchment, it is important to measure each component of its movement within the forest. Two years after the accident, we estimated the annual transportation of 137 Cs from the forest canopy to the floor by litterfall, throughfall and stemflow. Seasonal variations in 137 Cs transportation and differences between forests types were also determined. The total amount of 137 Cs transported from the canopy to the floor in two deciduous and cedar plantation forests ranged between 3.9 and 11.0 kBq m −2  year −1 . We also observed that 137 Cs transportation with litterfall increased in the defoliation period, simply because of the increased amount of litterfall. 137 Cs transportation with throughfall and stemflow increased in the rainy season, and 137 Cs flux by litterfall was higher in cedar plantation compared with that of mixed deciduous forest, while the opposite result was obtained for stemflow. - Highlights: • Annual flux of 137 Cs by litterfall, throughfall and stemflow was estimated in two types of forest in Fukushima, Japan. • Annual amount of 137 Cs transportation was 3.9–11.0 kBq m −2 year −1 in two years after the accident. • 137 Cs flux by litterfall was higher in cedar plantation than that of mixed deciduous forest. • 137 Cs transportation with throughfall and stemflow increased in rainy season.

  4. DRAINMOD-FOREST: Integrated Modeling of Hydrology, Soil Carbon and Nitrogen Dynamics, and Plant Growth for Drained Forests.

    Science.gov (United States)

    Tian, Shiying; Youssef, Mohamed A; Skaggs, R Wayne; Amatya, Devendra M; Chescheir, G M

    2012-01-01

    We present a hybrid and stand-level forest ecosystem model, DRAINMOD-FOREST, for simulating the hydrology, carbon (C) and nitrogen (N) dynamics, and tree growth for drained forest lands under common silvicultural practices. The model was developed by linking DRAINMOD, the hydrological model, and DRAINMOD-N II, the soil C and N dynamics model, to a forest growth model, which was adapted mainly from the 3-PG model. The forest growth model estimates net primary production, C allocation, and litterfall using physiology-based methods regulated by air temperature, water deficit, stand age, and soil N conditions. The performance of the newly developed DRAINMOD-FOREST model was evaluated using a long-term (21-yr) data set collected from an artificially drained loblolly pine ( L.) plantation in eastern North Carolina, USA. Results indicated that the DRAINMOD-FOREST accurately predicted annual, monthly, and daily drainage, as indicated by Nash-Sutcliffe coefficients of 0.93, 0.87, and 0.75, respectively. The model also predicted annual net primary productivity and dynamics of leaf area index reasonably well. Predicted temporal changes in the organic matter pool on the forest floor and in forest soil were reasonable compared to published literature. Both predicted annual and monthly nitrate export were in good agreement with field measurements, as indicated by Nash-Sutcliffe coefficients above 0.89 and 0.79 for annual and monthly predictions, respectively. This application of DRAINMOD-FOREST demonstrated its capability for predicting hydrology and C and N dynamics in drained forests under limited silvicultural practices. Copyright © by the American Society of Agronomy, Crop Science Society of America, and Soil Science Society of America, Inc.

  5. External Hand Forces Exerted by Long-Term Care Staff to Push Floor-Based Lifts: Effects of Flooring System and Resident Weight.

    Science.gov (United States)

    Lachance, Chantelle C; Korall, Alexandra M B; Russell, Colin M; Feldman, Fabio; Robinovitch, Stephen N; Mackey, Dawn C

    2016-09-01

    The aim of this study was to investigate the effects of flooring type and resident weight on external hand forces required to push floor-based lifts in long-term care (LTC). Novel compliant flooring is designed to reduce fall-related injuries among LTC residents but may increase forces required for staff to perform pushing tasks. A motorized lift may offset the effect of flooring on push forces. Fourteen female LTC staff performed straight-line pushes with two floor-based lifts (conventional, motor driven) loaded with passengers of average and 90th-percentile resident weights over four flooring systems (concrete+vinyl, compliant+vinyl, concrete+carpet, compliant+carpet). Initial and sustained push forces were measured by a handlebar-mounted triaxial load cell and compared to participant-specific tolerance limits. Participants rated pushing difficulty. Novel compliant flooring increased initial and sustained push forces and subjective ratings compared to concrete flooring. Compared to the conventional lift, the motor-driven lift substantially reduced initial and sustained push forces and perceived difficulty of pushing for all four floors and both resident weights. Participants exerted forces above published tolerance limits only when using the conventional lift on the carpet conditions (concrete+carpet, compliant+carpet). With the motor-driven lift only, resident weight did not affect push forces. Novel compliant flooring increased linear push forces generated by LTC staff using floor-based lifts, but forces did not exceed tolerance limits when pushing over compliant+vinyl. The motor-driven lift substantially reduced push forces compared to the conventional lift. Results may help to address risk of work-related musculoskeletal injury, especially in locations with novel compliant flooring. © 2016, Human Factors and Ergonomics Society.

  6. 76 FR 76435 - Multilayered Wood Flooring From China

    Science.gov (United States)

    2011-12-07

    ...)] Multilayered Wood Flooring From China Determinations On the basis of the record \\1\\ developed in the subject... multilayered wood flooring, provided for in subheadings 4409.10, 4409.29, 4412.31, 4412.32, 4412.39, 4412.94... flooring. The following companies are members of the CAHP: Anderson Hardwood Floors, LLC, Fountain Inn, SC...

  7. Cemented Horizons and Hardpans in the Coastal Tablelands of Northeastern Brazil

    Directory of Open Access Journals (Sweden)

    João Bosco Vasconcellos Gomes

    Full Text Available ABSTRACT Horizons with varying degrees of cementation are a common feature of the soils from the coastal tablelands of Northeastern Brazil. In most cases, these horizons are represented by the following subsurface horizons: fragipan, duripan, ortstein, and placic. The aims of this study were to analyze differences regarding the development and the degree of expression of cementation in soils from the coastal tablelands of Northeastern Brazil: Planossolo Háplico (p-SX, Espodossolo Humilúvico (p-EK, Espodossolo Ferrihumilúvico (p-ESK, and Argissolo Acinzentado (p-PAC pedons. The pedons studied displayed features related to drainage impediments. The cemented horizons from p-SX and p-EK had the same designation (Btgm, displaying a duric character that coincided with gleization features and are under podzolized horizons. In the p-ESK, the podzolization process is of such magnitude that it leads to the cementation of its own spodic horizons, which were both of the ortstein type (Bhsx and Bsm. In the p-PAC cementation is observed in two placic horizons and in the Btx/Bt horizon, as well as in the upper parts of the Bt/Btx horizon. Analysis of the micrographies from the cemented horizons showed predominance of a low porosity matrix. Such porosity is relatively greater in the horizons of “x” subscript than in the horizons with duric character. The Fe segregation lines were notable in the cemented horizons from p-EK and p-PAC, which corroborates the presence of placic horizons in such pedons. The preponderance of kaolinite in the clay fraction was widely verified in all the cemented horizons analyzed. Water immersion tests were the criteria adopted to define the duric character of the Btgm horizons from p-SX and p-EK, and in the Bsm horizon from the p-ESK. These tests were also used to confirm field morphology. In most cases, the maximum values of Fe, Al, and Si, determined by different extractions, occurred in positions overlaying the cemented

  8. VMware Horizon Workspace essentials

    CERN Document Server

    von Oven, Peter; Lindberg, Joel

    2014-01-01

    This book uses a step-by-step approach to teach you how to design, deploy, and manage a Horizon Workspace based on real world experience. Written in an easy-to-follow style, this book explains the terminology in a clear and concise manner. Each feature is explained starting at a high level and then drilling down into the technical detail, using diagrams and screenshots.This book is perfect for IT administrators who want to deploy a solution to centrally manage access to corporate applications, data, and virtual desktops using Horizon Workspace. You need to have some experience in delivering BY

  9. Microbiomes structure and diversity in different horizons of full soil profiles

    Science.gov (United States)

    Chernov, Timofey; Tkhakakhova, Azida; Zhelezova, Alena; Semenov, Mikhail; Kutovaya, Olga

    2017-04-01

    Topsoil is a most common object for soil metagenomic studies; sometimes soil profile is being formally split in layers by depth. However, Russian Soil Science School formulated the idea of soil profile as a complex of soil horizons, which can differ in their properties and genesis. In this research we analyzed 57 genetic soil horizons of 8 different soils from European part of Russia: Albeluvisol, Greyzemic Phaeozem, three Chermozems (different land use - till, fallow, wind-protecting tree line), Rhodic Cambisol, Haplic Kastanozem and Salic Solonetz (WRB classification). Sampling was performed from all genetic horizons in each soil profile starting from topsoil until subsoil. Total DNA was extracted and 16S rRNA sequencing was provided together with chemical analysis of soil (pH measurement, C and N contents, etc.). Structure and diversity of prokaryotic community are significantly different in those soil horizons, which chemical properties and processes of origin are contrasting with nearest horizons: Na-enriched horizon of Solonetz, eluvial horizon of Albeluvisol, plough pan of Agrochernozem. Actinobacteria were abundant in top horizons of soils in warm and dry climate, while Acidobacteria had the highest frequency in soils of moist and cold regions. Concerning Archaea, Thaumarchaeota prevailed in all studied soils. Their rate was higher in microbiomes of upper horizons of steppe soils and it was reducing with depth down the profile. Prokaryotic communities in Chernozems were clustered by soil horizons types: microbiomes of A (organic topsoil) and B (mineral) horizons formed non-overlapping clusters by principal component analysis, cluster formed by prokaryotic communities of transitional soil horizons (AB) take place between clusters of A and B horizons. Moreover, prokaryotic communities of A horizons differ from each other strongly, while microbiomes of B horizons formed a narrow small cluster. It must be explaned by more diverse conditions in upper A horizons

  10. Damage to the forest ecosystem on Blue Mountain from zinc smelting

    Science.gov (United States)

    Beyer, W.N.

    1988-01-01

    Emissions from two zinc smelters in Palmerton, Pennsylvania, have caused widespread destruction of the forest on Blue Mountain. There have been striking changes in the species composition and structure of the community of vascular plants, as well as population reductions of lichens, mosses, arthropods inhabiting the letter, and amphibians. Reductions in the populations of decomposers of organic matter have led to an accumulation of litter on the forest floor. Zinc poisoning was diagnosed in a white-tailed deer, and lead poisoning was diagnosed in a shrew. White-tailed deer also contained high concentrations of cadmium.

  11. Simulations show decreasing carbon stocks and potential for carbon emissions in Rocky Mountain forests over the next century.

    Science.gov (United States)

    Boisvenue, Céline; Running, Steven W

    2010-07-01

    Climate change has altered the environment in which forests grow, and climate change models predict more severe alterations to come. Forests have already responded to these changes, and the future temperature and precipitation scenarios are of foremost concern, especially in the mountainous western United States, where forests occur in the dry environments that interface with grasslands. The objective of this study was to understand the trade-offs between temperature and water controls on these forested sites in the context of available climate projections. Three temperature and precipitation scenarios from IPCC AR4 AOGCMs ranging in precipitation levels were input to the process model Biome-BGC for key forested sites in the northern U.S. Rocky Mountains. Despite the omission of natural and human-caused disturbances in our simulations, our results show consequential effects from these conservative future temperature and precipitation scenarios. According to these projections, if future precipitation and temperatures are similar to or drier than the dry scenario depicted here, high-elevation forests on both the drier and wetter sites, which have in the absence of disturbance accumulated carbon, will reduce their carbon accumulation. Under the marginally drier climate projections, most forests became carbon sources by the end of the simulation horizon (2089). Under all three scenarios, growing season lengthened, the number of days with snow on the ground decreased, peak snow occurred earlier, and water stress increased through the projection horizon (1950-2089) for all sites, which represent the temperature and precipitation spectrum of forests in this region. The quantity, form, and timing of precipitation ultimately drive the carbon accumulation trajectory of forests in this region.

  12. Radiant Floor Cooling Systems

    DEFF Research Database (Denmark)

    Olesen, Bjarne W.

    2008-01-01

    In many countries, hydronic radiant floor systems are widely used for heating all types of buildings such as residential, churches, gymnasiums, hospitals, hangars, storage buildings, industrial buildings, and smaller offices. However, few systems are used for cooling.This article describes a floor...... cooling system that includes such considerations as thermal comfort of the occupants, which design parameters will influence the cooling capacity and how the system should be controlled. Examples of applications are presented....

  13. The influence of time horizon on results of cost-effectiveness analyses.

    Science.gov (United States)

    Kim, David D; Wilkinson, Colby L; Pope, Elle F; Chambers, James D; Cohen, Joshua T; Neumann, Peter J

    2017-12-01

    Debates persist on the appropriate time horizon from a payer's perspective and how the time horizon in cost-effectiveness analysis (CEA) influences the value assessment. We systematically reviewed the Tufts Medical Center CEA Registry and identified US-based studies that used a payer perspective from 2005-2014. We classified the identified CEAs as short-term (time horizon ≤ 5 years) and long-term (> 5 years), and examined associations between study characteristics and the specified time horizon. We also developed case studies with selected interventions to further explore the relationship between time horizon and projected costs, benefits, and incremental cost-effectiveness ratios (ICER). Among 782 identified studies that met our inclusion criteria, 552 studies (71%) utilized a long-term time horizon while 198 studies (25%) used a short-term horizon. Among studies that employed multiple time horizons, the extension of the time horizon yielded more favorable ICERs in 19 cases and less favorable ICERs in 4 cases. Case studies showed the use of a longer time horizon also yielded more favorable ICERs. The assumed time horizon in CEAs can substantially influence the value assessment of medical interventions. To capture all consequences, we encourage the use of time horizons that extend sufficiently into the future.

  14. Hydrological response to bauxite mining and rehabilitation in the jarrah forest in south west Australia

    Directory of Open Access Journals (Sweden)

    Andrew H. Grigg

    2017-08-01

    New hydrological insights for the region: Mining caused a peak streamflow response of 225 mm or 18% of rainfall, before returning to pre-disturbance levels 11 years after mining commenced. Streamflow changes were closely associated with changes in a groundwater discharge area in the valley floor. Changes in groundwater level, in turn, were related to rainfall and leaf area index, and these effects did not differ between mine rehabilitation and unmined catchment areas. The streamflow response to mining could not be distinguished from the intensive thinning treatment in this study, or from clearfelling or clearing for agriculture reported elsewhere in the jarrah forest. The results indicate that shallow subsurface flow processes, considered to dominate streamflow generation in jarrah forest catchments, do not extend beyond the valley floor and immediately adjacent slopes which were not disturbed by mining.

  15. Magnetic resonance imaging of pelvic floor dysfunction.

    Science.gov (United States)

    Lalwani, Neeraj; Moshiri, Mariam; Lee, Jean H; Bhargava, Puneet; Dighe, Manjiri K

    2013-11-01

    Pelvic floor dysfunction is largely a complex problem of multiparous and postmenopausal women and is associated with pelvic floor or organ descent. Physical examination can underestimate the extent of the dysfunction and misdiagnose the disorders. Functional magnetic resonance (MR) imaging is emerging as a promising tool to evaluate the dynamics of the pelvic floor and use for surgical triage and operative planning. This article reviews the anatomy and pathology of pelvic floor dysfunction, typical imaging findings, and the current role of functional MR imaging. Copyright © 2013 Elsevier Inc. All rights reserved.

  16. [Continuous improvement of portable domestic pelvic floor neuromuscular electrical stimulation on the pelvic floor function of patients with urinary incontinence].

    Science.gov (United States)

    Sun, Zhijing; Zhu, Lan; Lang, Jinghe; Wang, Wei; Shi, Honghui; Pang, Hongxia; Shi, Xinwen

    2015-12-01

    To evaluate continuous improvement of portable domestic pelvic floor neuromuscular electrical stimulation on the pelvic floor function of patients with stress urinary incontinence after short-term pelvic floor electrophysiological treatment in hospital. Totally 60 women with stress urinary incontinence were recruited for this randomized controlled trial. The control group including a total of 30 patients, only received 4 weeks pelvic floor electrophysiological treatment in the hospital. Family consolidation treatment group (experimental group) including 30 patients, after 4-week treatment in hospital, received 12-week of pelvic floor neuromuscular electrical stimulation using portable electrical stimulator at home under the guidance of doctors. In post-treatment 6 months and 9 months, 1-hour pad test was measured for urine leakage, pelvic floor electrical physiological parameters were assessed, and subjective improvement of symptoms of urinary incontinence were evaluated. All these data were analysed to compare the effect of the two groups. In 9 months after treatment, average change of urine leakage, the control group and experiment group were (75±24)% versus (99±3)%, the difference was statistically significant (Pcontinuous improvement of pelvic floor function.

  17. Low-level gamma spectrometry of forest and moor soils from exposed mountain regions in Saxony (Erzgebirge)

    Energy Technology Data Exchange (ETDEWEB)

    Schleich, N [Technische Univ. Bergakademie Freiberg (Germany). Inst. of Applied Physics; Preusse, W [Technische Univ. Bergakademie Freiberg (Germany). Inst. of Applied Physics; Degering, D [Technische Univ. Bergakademie Freiberg (Germany). Inst. of Applied Physics; Unterricker, S [Technische Univ. Bergakademie Freiberg (Germany). Inst. of Applied Physics

    1997-03-01

    In soils with distinct organic and mineral horizons, radionuclides (RN) can be used to understand geochemical migration processes. In the study presented here high sensitivity HPGe-detectors with active and passive shielding were employed to determine the low activity levels of various natural, cosmogenic and artificial RN. Soils of a spruce forest and a moor from exposed mountain regions in Saxony (Erzgebirge) were investigated as they provide a good example of layered soil systems with vertical transfer of chemical elements. Different soil horizons were sub-sampled as thin slices and analysed to examine the migration processes at sub-horizon level. The depth distributions of chemically different RN were studied considering the geochemical and pedological soil characteristics of the profiles. (orig.)

  18. Cosmological event horizons, thermodynamics, and particle creation

    International Nuclear Information System (INIS)

    Gibbons, G.W.; Hawking, S.W.

    1977-01-01

    It is shown that the close connection between event horizons and thermodynamics which has been found in the case of black holes can be extended to cosmological models with a repulsive cosmological constant. An observer in these models will have an event horizon whose area can be interpreted as the entropy or lack of information of the observer about the regions which he cannot see. Associated with the event horizon is a surface gravity kappa which enters a classical ''first law of event horizons'' in a manner similar to that in which temperature occurs in the first law of thermodynamics. It is shown that this similarity is more than an analogy: An observer with a particle detector will indeed observe a background of thermal radiation coming apparently from the cosmological event horizon. If the observer absorbs some of this radiation, he will gain energy and entropy at the expense of the region beyond his ken and the event horizon will shrink. The derivation of these results involves abandoning the idea that particles should be defined in an observer-independent manner. They also suggest that one has to use something like the Everett-Wheeler interpretation of quantum mechanics because the back reaction and hence the spacetime metric itself appear to be observer-dependent, if one assumes, as seems reasonable, that the detection of a particle is accompanied by a change in the gravitational field

  19. Modular Flooring System

    Science.gov (United States)

    Thate, Robert

    2012-01-01

    The modular flooring system (MFS) was developed to provide a portable, modular, durable carpeting solution for NASA fs Robotics Alliance Project fs (RAP) outreach efforts. It was also designed to improve and replace a modular flooring system that was too heavy for safe use and transportation. The MFS was developed for use as the flooring for various robotics competitions that RAP utilizes to meet its mission goals. One of these competitions, the FIRST Robotics Competition (FRC), currently uses two massive rolls of broadloom carpet for the foundation of the arena in which the robots are contained during the competition. The area of the arena is approximately 30 by 72 ft (approximately 9 by 22 m). This carpet is very cumbersome and requires large-capacity vehicles, and handling equipment and personnel to transport and deploy. The broadloom carpet sustains severe abuse from the robots during a regular three-day competition, and as a result, the carpet is not used again for competition. Similarly, broadloom carpets used for trade shows at convention centers around the world are typically discarded after only one use. This innovation provides a green solution to this wasteful practice. Each of the flooring modules in the previous system weighed 44 lb (.20 kg). The improvements in the overall design of the system reduce the weight of each module by approximately 22 lb (.10 kg) (50 %), and utilize an improved "module-to-module" connection method that is superior to the previous system. The MFS comprises 4-by-4-ft (.1.2-by- 1.2-m) carpet module assemblies that utilize commercially available carpet tiles that are bonded to a lightweight substrate. The substrate surface opposite from the carpeted surface has a module-to-module connecting interface that allows for the modules to be connected, one to the other, as the modules are constructed. This connection is hidden underneath the modules, creating a smooth, co-planar flooring surface. The modules are stacked and strapped

  20. Horizon quantum mechanics of rotating black holes

    Energy Technology Data Exchange (ETDEWEB)

    Casadio, Roberto [Universita di Bologna, Dipartimento di Fisica e Astronomia, Bologna (Italy); I.N.F.N., Sezione di Bologna, I.S. FLAG, Bologna (Italy); Giugno, Andrea [Ludwig-Maximilians-Universitaet, Arnold Sommerfeld Center, Munich (Germany); Giusti, Andrea [Universita di Bologna, Dipartimento di Fisica e Astronomia, Bologna (Italy); I.N.F.N., Sezione di Bologna, I.S. FLAG, Bologna (Italy); Ludwig-Maximilians-Universitaet, Arnold Sommerfeld Center, Munich (Germany); Micu, Octavian [Institute of Space Science, Bucharest, P.O. Box MG-23, Bucharest-Magurele (Romania)

    2017-05-15

    The horizon quantum mechanics is an approach that was previously introduced in order to analyze the gravitational radius of spherically symmetric systems and compute the probability that a given quantum state is a black hole. In this work, we first extend the formalism to general space-times with asymptotic (ADM) mass and angular momentum. We then apply the extended horizon quantum mechanics to a harmonic model of rotating corpuscular black holes. We find that simple configurations of this model naturally suppress the appearance of the inner horizon and seem to disfavor extremal (macroscopic) geometries. (orig.)

  1. Bootstrap, universality and horizons

    Energy Technology Data Exchange (ETDEWEB)

    Chang, Chi-Ming [Center for Theoretical Physics and Department of Physics,University of California, Berkeley, CA 94704 (United States); Lin, Ying-Hsuan [Jefferson Physical Laboratory, Harvard University,Cambridge, MA 02138 (United States)

    2016-10-13

    We present a closed form expression for the semiclassical OPE coefficients that are universal for all 2D CFTs with a “weak” light spectrum, by taking the semiclassical limit of the fusion kernel. We match this with a properly regularized and normalized bulk action evaluated on a geometry with three conical defects, analytically continued in the deficit angles beyond the range for which a metric with positive signature exists. The analytically continued geometry has a codimension-one coordinate singularity surrounding the heaviest conical defect. This singularity becomes a horizon after Wick rotating to Lorentzian signature, suggesting a connection between universality and the existence of a horizon.

  2. Knowledge of the pelvic floor in nulliparous women

    OpenAIRE

    Neels, Hedwig; Wyndaele, Jean-Jacques; Tjalma, Wiebren A. A.; De Wachter, Stefan; Wyndaele, Michel; Vermandel, Alexandra

    2016-01-01

    [Purpose] Proper pelvic floor function is important to avoid serious dysfunctions including incontinence, prolapse, and sexual problems. The current study evaluated the knowledge of young nulliparous women about their pelvic floor and identified what additional information they wanted. [Subjects and Methods] In this cross-sectional survey, a validated, 36 item questionnaire was distributed to 212 nulliparous women. The questionnaire addressed demography, pelvic floor muscles, pelvic floor dys...

  3. Edge effects on foliar stable isotope values in a Madagascan tropical dry forest.

    Directory of Open Access Journals (Sweden)

    Brooke E Crowley

    Full Text Available Edge effects represent an inevitable and important consequence of habitat loss and fragmentation. These effects include changes in microclimate, solar radiation, or temperature. Such abiotic effects can, in turn, impact biotic factors. They can have a substantial impact on species, communities, and ecosystems. Here we examine clinal variations in stable carbon and nitrogen isotope values for trees along an edge-interior gradient in the dry deciduous forest at Ankarafantsika National Park. We predicted that soil respiration and differences in solar irradiance would result in stratified δ¹³C values where leaves collected close to the forest floor would have lower δ¹³C values than those growing higher up in the canopy. We also anticipated that plants growing at the savannah-forest boundary would have higher δ¹³C and δ¹⁵N values than plants growing in the forest interior. As expected, we detected a small but significant canopy effect. Leaves growing below 2 m from the forest floor exhibit δ¹³C values that are, on average, 1.1‰ lower than those growing above this threshold. We did not, however, find any relationship between foliar δ¹³C and distance from the edge. Unpredictably, we detected a striking positive relationship between foliar δ¹⁵N values and increasing distance into the forest interior. Variability in physiology among species, anthropogenic influence, organic input, and rooting depth cannot adequately explain this trend. Instead, this unexpected relationship most likely reflects decreasing nutrient or water availability, or a shift in N-sources with increasing distance from the savannah. Unlike most forest communities, the trees at Ampijoroa are growing in nutrient-limited sands. In addition to being nutrient poor, these well-drained soils likely decrease the amount of soil water available to forest vegetation. Continued research on plant responses to edge effects will improve our understanding of the conservation

  4. Effects of ground fires on element dynamics in mountainous coniferous forest in Germany

    Directory of Open Access Journals (Sweden)

    Kerstin Näthe

    2012-09-01

    Full Text Available Disturbances such as fires are a natural phenomenon of forested ecosystems, having a different impact on (micro- climate (e.g. emissions of gases and aerosols, ecology (destruction of flora and fauna and nutrient cycles especially in the soils. Forest fires alter the spatial distribution (forest floor vs. mineral soil, binding forms (organic vs. inorganic and availability (water solubility of organic substances and nutrients. The effects of fires on chemical, biological and physical soil properties in forested ecosystems have been intensively studied in the last decades, especially in the Mediterranean area and North America. However, differences in fire intensity, forest type (species, age and location (climate, geological substrate, nutrient status lead to divergent results. Furthermore, only a few case studies focused on the effects of ground fires in hilly landscapes, on the vertical and lateral water-driven fluxes of elements (C, N, nutrients, as well as on the input of fire-released terrestrial nutrients into aquatic ecosystems. Thus, this study will evaluate the effects of low-severity fires on nutrient cycling in a coniferous forest in a hilly landscape connected to an aquatic system. At three spatially independent sites three paired plots (control and manipulated were chosen at a forested site in Thuringia, Germany. All plots are similar in the vegetation cover and pedogenetic properties.In relation to control sites, this study will examine the effects of low-severity fires on:a the mobilization of organic carbon and nutrients (released from ash material and the forest floor via leachate and erosion paths,b the binding form (inorganic/organic of elements and organic compounds, and c the particle size fraction (DOM/POM of elements and organic compounds.The goal of this study is a better understanding of the impact of forest fires on element cycling and release in a hilly landscape connected to an aquatic system, supposedly driven by

  5. Redshift of a photon emitted along the black hole horizon

    Energy Technology Data Exchange (ETDEWEB)

    Toporensky, A.V. [Lomonosov Moscow State University, Sternberg Astronomical Institute, Moscow (Russian Federation); Kazan Federal University, Kazan (Russian Federation); Zaslavskii, O.B. [Kazan Federal University, Kazan (Russian Federation); Kharkov V.N. Karazin National University, Department of Physics and Technology, Kharkov (Ukraine)

    2017-03-15

    In this work we derive some general features of the redshift measured by radially moving observers in the black hole background. Let observer 1 cross the black hole horizon emitting a photon, while observer 2 crossing the same horizon later receives it. We show that if (i) the horizon is the outer one (event horizon) and (ii) it is nonextremal, the received frequency is redshifted. This generalizes recent results in the literature. For the inner horizon (like in the Reissner-Nordstroem metric) the frequency is blueshifted. If the horizon is extremal, the frequency does not change. We derive explicit formulas describing the frequency shift in generalized Kruskal- and Lemaitre-like coordinates. (orig.)

  6. Pricing Liquidity Risk with Heterogeneous Investment Horizons

    NARCIS (Netherlands)

    Beber, Alessandro; Driessen, Joost; Neuberger, A.; Tuijp, P

    We develop an asset pricing model with stochastic transaction costs and investors with heterogeneous horizons. Depending on their horizon, investors hold different sets of assets in equilibrium. This generates segmentation and spillover effects for expected returns, where the liquidity (risk)

  7. Reflection, radiation, and interference near the black hole horizon

    International Nuclear Information System (INIS)

    Kuchiev, M.Yu.

    2004-01-01

    The event horizon of black holes is capable of reflection: there is a finite probability for any particle that approaches the horizon to bounce back. The albedo of the horizon depends on the black hole temperature and the energy of the incoming particle. The reflection shares its physical origins with the Hawking process of radiation; both of them arise as consequences of the mixing of the incoming and outgoing waves that takes place due to quantum processes on the event horizon

  8. Plasmonic Horizon in Gold Nanosponges.

    Science.gov (United States)

    Vidal, Cynthia; Sivun, Dmitry; Ziegler, Johannes; Wang, Dong; Schaaf, Peter; Hrelescu, Calin; Klar, Thomas A

    2018-02-14

    An electromagnetic wave impinging on a gold nanosponge coherently excites many electromagnetic hot-spots inside the nanosponge, yielding a polarization-dependent scattering spectrum. In contrast, a hole, recombining with an electron, can locally excite plasmonic hot-spots only within a horizon given by the lifetime of localized plasmons and the speed carrying the information that a plasmon has been created. This horizon is about 57 nm, decreasing with increasing size of the nanosponge. Consequently, photoluminescence from large gold nanosponges appears unpolarized.

  9. Container floor at high temperatures

    International Nuclear Information System (INIS)

    Reutler, H.; Klapperich, H.J.; Mueller-Frank, U.

    1978-01-01

    The invention describes a floor for container which is stressed at high, changing temperatures and is intended for use in gas-cooled nuclear reactors. Due to the downward cooling gas flow in these types of reactor, the reactor floor is subjected to considerable dimensional changes during switching on and off. In the heating stage, the whole graphite structure of the reactor core and floor expands. In order to avoid arising constraining forces, sufficiently large expansion spaces must be allowed for furthermore restoring forces must be present to close the gaps again in the cooling phase. These restoring forces must be permanently present to prevent loosening of the core cuits amongst one another and thus uncontrollable relative movement. Spring elements are not suitable due to fast fatigue as a result of high temperatures and radiation exposure. It is suggested to have the floor elements supported on rollers whose rolling planes are downwards inclined to a fixed point for support. The construction is described in detail by means of drawings. (GL) [de

  10. Nitrogen distribution and cycling through water flows in a subtropical bamboo forest under high level of atmospheric deposition.

    Science.gov (United States)

    Tu, Li-hua; Hu, Ting-xing; Zhang, Jian; Huang, Li-hua; Xiao, Yin-long; Chen, Gang; Hu, Hong-ling; Liu, Li; Zheng, Jiang-kun; Xu, Zhen-Feng; Chen, Liang-hua

    2013-01-01

    The hydrological cycle is an important way of transportation and reallocation of reactive nitrogen (N) in forest ecosystems. However, under a high level of atmospheric N deposition, the N distribution and cycling through water flows in forest ecosystems especially in bamboo ecosystems are not well understood. In order to investigate N fluxes through water flows in a Pleioblastus amarus bamboo forest, event rainfall/snowfall (precipitation, PP), throughfall (TF), stemflow (SF), surface runoff (SR), forest floor leachate (FFL), soil water at the depth of 40 cm (SW1) and 100 cm (SW2) were collected and measured through the whole year of 2009. Nitrogen distribution in different pools in this ecosystem was also measured. Mean N pools in vegetation and soil (0-1 m) were 351.7 and 7752.8 kg ha(-1). Open field nitrogen deposition at the study site was 113.8 kg N ha(-1) yr(-1), which was one of the highest in the world. N-NH4(+), N-NO3(-) and dissolved organic N (DON) accounted for 54%, 22% and 24% of total wet N deposition. Net canopy accumulated of N occurred with N-NO3(-) and DON but not N-NH4(+). The flux of total dissolved N (TDN) to the forest floor was greater than that in open field precipitation by 17.7 kg N ha(-1) yr(-1), due to capture of dry and cloudwater deposition net of canopy uptake. There were significant negative exponential relationships between monthly water flow depths and monthly mean TDN concentrations in PP, TF, SR, FFL and SW1. The open field nitrogen deposition through precipitation is very high over the world, which is the main way of reactive N input in this bamboo ecosystem. The water exchange and N consume mainly occurred in the litter floor layer and topsoil layer, where most of fine roots of bamboo distributed.

  11. No bulging of floor heating pipes to be expected in case of incomplete floor plastering

    Energy Technology Data Exchange (ETDEWEB)

    Radtke, U

    1983-02-01

    According to advertising slogans floor heating pipes are said to be damaged prematurely by bulges if they are not completely surrounded by flooring plaster. The author has thoroughly dealt with this problem and made the respective measurements. He found out that there are so few bulges occurring that they cannot lead to damages.

  12. [A comparative study on soil fauna in native secondary evergreen broad-leaved forest and Chinese fir plantation forests in subtropics].

    Science.gov (United States)

    Yan, Shaokui; Wang, Silong; Hu, Yalin; Gao, Hong; Zhang, Xiuyong

    2004-10-01

    In this study, we investigated the response of soil animal communities to the replacement of native secondary forest by Chinese fir plantation forest and successive rotation of Chinese fir in subtropics. Three adjacent forest stands, i.e., native secondary evergreen broad-leaved forest stand (control) and Chinese fir plantation stands of first (20 yr) and second (20 yr) rotations were selected for the comparison of soil fauna. All animals were extracted from the floor litter and 0-15 cm soil layer of the stands in Summer, 2003 by using Tullgren method, wet funnel method and hand-sorting method. Compared to two Chinese fir plantation forests, the native secondary evergreen broad-leaved forest had a higher abundance and a higher taxonomic diversity of animals in soil and litter, but there were no significant differences in the biomass and productivity of soil fauna between all study stands. The abundance or diversity did not differ significantly between the first rotation and second rotation stands, too. The results supported that vegetation cover might be one of the main forces driving the development of soil animal communities, and the effect of successive rotation of Chinese fir on the development of soil fauna was a slow-running process.

  13. Recognition and Management of Nonrelaxing Pelvic Floor Dysfunction

    OpenAIRE

    Faubion, Stephanie S.; Shuster, Lynne T.; Bharucha, Adil E.

    2012-01-01

    Nonrelaxing pelvic floor dysfunction is not widely recognized. Unlike in pelvic floor disorders caused by relaxed muscles (eg, pelvic organ prolapse or urinary incontinence, both of which often are identified readily), women affected by nonrelaxing pelvic floor dysfunction may present with a broad range of nonspecific symptoms. These may include pain and problems with defecation, urination, and sexual function, which require relaxation and coordination of pelvic floor muscles and urinary and ...

  14. Quantum-corrected geometry of horizon vicinity

    Energy Technology Data Exchange (ETDEWEB)

    Park, I.Y. [Department of Applied Mathematics, Philander Smith College, Little Rock, AR (United States)

    2017-12-15

    We study the deformation of the horizon-vicinity geometry caused by quantum gravitational effects. Departure from the semi-classical picture is noted, and the fact that the matter part of the action comes at a higher order in Newton's constant than does the Einstein-Hilbert term is crucial for the departure. The analysis leads to a Firewall-type energy measured by an infalling observer for which quantum generation of the cosmological constant is critical. The analysis seems to suggest that the Firewall should be a part of such deformation and that the information be stored both in the horizon-vicinity and asymptotic boundary region. We also examine the behavior near the cosmological horizon. (copyright 2017 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  15. Quantum-corrected geometry of horizon vicinity

    International Nuclear Information System (INIS)

    Park, I.Y.

    2017-01-01

    We study the deformation of the horizon-vicinity geometry caused by quantum gravitational effects. Departure from the semi-classical picture is noted, and the fact that the matter part of the action comes at a higher order in Newton's constant than does the Einstein-Hilbert term is crucial for the departure. The analysis leads to a Firewall-type energy measured by an infalling observer for which quantum generation of the cosmological constant is critical. The analysis seems to suggest that the Firewall should be a part of such deformation and that the information be stored both in the horizon-vicinity and asymptotic boundary region. We also examine the behavior near the cosmological horizon. (copyright 2017 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  16. Floor-Fractured Craters through Machine Learning Methods

    Science.gov (United States)

    Thorey, C.

    2015-12-01

    Floor-fractured craters are impact craters that have undergone post impact deformations. They are characterized by shallow floors with a plate-like or convex appearance, wide floor moats, and radial, concentric, and polygonal floor-fractures. While the origin of these deformations has long been debated, it is now generally accepted that they are the result of the emplacement of shallow magmatic intrusions below their floor. These craters thus constitute an efficient tool to probe the importance of intrusive magmatism from the lunar surface. The most recent catalog of lunar-floor fractured craters references about 200 of them, mainly located around the lunar maria Herein, we will discuss the possibility of using machine learning algorithms to try to detect new floor-fractured craters on the Moon among the 60000 craters referenced in the most recent catalogs. In particular, we will use the gravity field provided by the Gravity Recovery and Interior Laboratory (GRAIL) mission, and the topographic dataset obtained from the Lunar Orbiter Laser Altimeter (LOLA) instrument to design a set of representative features for each crater. We will then discuss the possibility to design a binary supervised classifier, based on these features, to discriminate between the presence or absence of crater-centered intrusion below a specific crater. First predictions from different classifier in terms of their accuracy and uncertainty will be presented.

  17. QFT holography near the horizon of Schwarzschild-like spacetimes

    OpenAIRE

    Moretti, Valter; Pinamonti, Nicola

    2003-01-01

    It is argued that free QFT can be defined on the event horizon of a Schwarzschild-like spacetime and that this theory is unitarily and algebraically equivalent to QFT in the bulk (near the horizon). Under that unitary equivalence the bulk hidden SL(2,R) symmetry found in a previous work becomes manifest on the event horizon, it being induced by a group of horizon diffeomorphisms. The class of generators of that group can be enlarged to include a full Virasoro algebra of fields which are defin...

  18. Potential increases in natural disturbance rates could offset forest management impacts on ecosystem carbon stocks

    Science.gov (United States)

    Bradford, John B.; Jensen, Nicholas R.; Domke, Grant M.; D’Amato, Anthony W.

    2013-01-01

    Forested ecosystems contain the majority of the world’s terrestrial carbon, and forest management has implications for regional and global carbon cycling. Carbon stored in forests changes with stand age and is affected by natural disturbance and timber harvesting. We examined how harvesting and disturbance interact to influence forest carbon stocks over the Superior National Forest, in northern Minnesota. Forest inventory data from the USDA Forest Service, Forest Inventory and Analysis program were used to characterize current forest age structure and quantify the relationship between age and carbon stocks for eight forest types. Using these findings, we simulated the impact of alternative management scenarios and natural disturbance rates on forest-wide terrestrial carbon stocks over a 100-year horizon. Under low natural mortality, forest-wide total ecosystem carbon stocks increased when 0% or 40% of planned harvests were implemented; however, the majority of forest-wide carbon stocks decreased with greater harvest levels and elevated disturbance rates. Our results suggest that natural disturbance has the potential to exert stronger influence on forest carbon stocks than timber harvesting activities and that maintaining carbon stocks over the long-term may prove difficult if disturbance frequency increases in response to climate change.

  19. Hydrological classification of orthic A horizons in Weatherley, South ...

    African Journals Online (AJOL)

    Orthic A horizons carry little interpretive, especially hydrological, value. This paper aims to elucidate the hydrological interpretation of orthic A horizons. Measured water contents in the orthic A horizons of 28 profiles in the Weatherley catchment of South Africa were used to classify the topsoils into wetness classes. The very ...

  20. Comparison of panoramic radiograph with cone-beam computed tomography in assessment of maxillary sinus floor and nasal floor

    Directory of Open Access Journals (Sweden)

    Vijay Kumar Bokkasam

    2015-01-01

    Full Text Available Introduction: Panoramic radiograph is frequently prescribed by dentists for implant planning and, hence, accurate assessment of anatomical structures in panoramic radiograph is of utmost importance. Aims: The aim of the present study is to know the accuracy of panoramic radiograph in assessment of relationship between maxillary sinus floor and posterior teeth roots, and the distance from alveolar crest to nasal floor by comparing it with that of cone-beam computed tomographic (CBCT image. Materials and Methods: Panoramic and CBCT images of 30 patients were analyzed. The topographic relationship of each root of posterior teeth to the maxillary sinus floor was evaluated and classified into three classes. The distance from the peak point on maxillary alveolar crest to nasal floor was measured in panoramic radiograph as well as in CBCT image. All the measurements were made by built-in measurement tools. Results: Class 1 roots in panoramic radiograph showed high agreement (86% with CBCT image, followed by class 0 (76%. There was a significant difference in the measurements of alveolar bone height (ABH in the nasal floor region with a P value of 0.018. Conclusion: Panoramic radiograph is reliable in assessment of nasal floor and maxillary sinus, provided position of the patient, distortion, and the inherent magnification factor are taken into consideration.

  1. Migration of 137Cs in soils and its transfer to mushrooms and vascular plants in mixed forest

    International Nuclear Information System (INIS)

    Pietrzak-Flis, Z.; Radwan, I.; Rosiak, L.; Wirth, E.

    1996-01-01

    Migration of 137 Cs in the podzol soil and transfer of 137 Cs, 134 Cs and potassium from the soil to mushrooms and vascular plants in the mixed forest at the Kampinos National Park near Warsaw, Poland, was studied in 1994 at locations lying about 6 km apart. In the soil at both locations, up to about 40% of 137 Cs was present in the Of horizon and slightly less in the mixed organic/mineral OhAh horizon. The data indicate a slow vertical migration of radiocesium. Total content of 137 Cs in the soils was 3000 Bq m -2 . The enrichment of the Of horizon in 137 Cs from the decomposing mushroom fruitbodies was evaluated and it was shown that it can significantly contribute to the horizontal displacement of radiocesium. Transfer factors (TF) for mushrooms and Calluna were calculated using the concentrations of 137 Cs in the Of horizons, whereas for grass, Vaccinium myrtillus and Polypodium vulgare TF were calculated using a weighted mean concentration of 137 Cs in the nutritive horizons with organic matter as a weight

  2. Competition, Time Horizon and Corporate Social Performance

    NARCIS (Netherlands)

    Graafland, J.J.; Smid, H.

    2013-01-01

    Abstract: This paper develops and tests a conceptual framework on the relationships between competition, time horizon and corporate social performance (CSP). We hypothesize that more intense competition discourages CSP by lowering the time horizon of companies. We test the hypothesis on a sample of

  3. Maximal indecomposable past sets and event horizons

    International Nuclear Information System (INIS)

    Krolak, A.

    1984-01-01

    The existence of maximal indecomposable past sets MIPs is demonstrated using the Kuratowski-Zorn lemma. A criterion for the existence of an absolute event horizon in space-time is given in terms of MIPs and a relation to black hole event horizon is shown. (author)

  4. Throughfall and stemflow chemistry in a northern hardwood forest

    Energy Technology Data Exchange (ETDEWEB)

    Eaton, J S; Likens, G E; Bormann, F H

    1973-01-01

    The contribution of throughfall and stemflow as pathways of the intrasystem nutrient cycle within the forested Hubbard Brook ecosystem was investigated. Nutrients followed were Ca, Mg, K, Na, NO/sub 3/, SO/sub 4/, NH/sub 4/, Fl, PO/sub 4/, H, organic N, and organic matter. Variation in throughfall and stemflow chemistry were determined under American beech, sugar maple, and yellow birch, the three major species comprising the forest studied. Nutrients generally recognized as being associated with organic molecules (e.g. P, N) moved more slowly from the forest canopy to the forest floor. These nutrients moved out of the canopy primarily via litterfall. Nutrients more commonly found in an ionic form (e.g. K) were found to move very rapidly from the forest canopy to the available nutrient pool in throughfall and stemflow. A comparison is made between the amount of each nutrient present in the forest canopy and the amount of these nutrients found in the throughfall and stemflow. The importance of hydrogen ion exchange in the removal of cations from the forest canopy is shown. Precipitation of low pH probably acts to accelerate the intrasystem cycling of nutrients within forested ecosystems. Total nutrient removal from the forest canopy by throughfall and stemflow is presented along with a comparison with the removal by litterfall.

  5. Forest Delineation Based on Airborne LIDAR Data

    Directory of Open Access Journals (Sweden)

    Norbert Pfeifer

    2012-03-01

    Full Text Available The delineation of forested areas is a critical task, because the resulting maps are a fundamental input for a broad field of applications and users. Different national and international forest definitions are available for manual or automatic delineation, but unfortunately most definitions lack precise geometrical descriptions for the different criteria. A mandatory criterion in forest definitions is the criterion of crown coverage (CC, which defines the proportion of the forest floor covered by the vertical projection of the tree crowns. For loosely stocked areas, this criterion is especially critical, because the size and shape of the reference area for calculating CC is not clearly defined in most definitions. Thus current forest delineations differ and tend to be non-comparable because of different settings for checking the criterion of CC in the delineation process. This paper evaluates a new approach for the automatic delineation of forested areas, based on airborne laser scanning (ALS data with a clearly defined method for calculating CC. The new approach, the ‘tree triples’ method, is based on defining CC as a relation between the sum of the crown areas of three neighboring trees and the area of their convex hull. The approach is applied and analyzed for two study areas in Tyrol, Austria. The selected areas show a loosely stocked forest at the upper timberline and a fragmented forest on the hillside. The fully automatic method presented for delineating forested areas from ALS data shows promising results with an overall accuracy of 96%, and provides a beneficial tool for operational applications.

  6. Long-term nitrogen regulation of forest carbon sequestration

    Science.gov (United States)

    Yang, Y.; Luo, Y.

    2009-12-01

    It is well established that nitrogen (N) limits plant production but unclear how N regulates long-term terrestrial carbon (C) sequestration in response to rising atmospheric C dioxide (CO2)(Luo et al., 2004). Most experimental evidence on C-N interactions is primarily derived from short-term CO2 manipulative studies (e.g. Oren et al., 2001; Reich et al., 2006a), which abruptly increase C inputs into ecosystems and N demand from soil while atmospheric CO2 concentration in the real world is gradually increasing over time (Luo & Reynolds, 1999). It is essential to examine long-term N regulations of C sequestration in natural ecosystems. Here we present results of a synthesis of more than 100 studies on long-term C-N interactions during secondary succession. C significantly accumulates in plant, litter and forest floor in most studies, and in mineral soil in one-third studies during stand development. Substantial increases in C stock are tightly coupled with N accretion. The C: N ratio in plant increases with stand age in most cases, but remains relatively constant in litter, forest floor and mineral soil. Our results suggest that natural ecosystems could have the intrinsic capacity to maintain long-term C sequestration through external N accrual, high N use efficiency, and efficient internal N cycling.

  7. Imaging pelvic floor disorders. 2. rev. ed.

    International Nuclear Information System (INIS)

    Stoker, Jaap; Taylor, Stuart A.; DeLancey, John O.L.

    2008-01-01

    This volume builds on the success of the first edition of imaging pelvic floor disorders and is aimed at those practitioners with an interest in the imaging, diagnosis and treatment of pelvic floor dysfunction. Concise textual information from acknowledged experts is complemented by high-quality diagrams and images to provide a thorough update of this rapidly evolving field. Introductory chapters fully elucidate the anatomical basis underlying disorders of the pelvic floor. State of the art imaging techniques and their application in pelvic floor dysfunction are then discussed in detail. Additions since the first edition include consideration of the effect of aging and new chapters on perineal ultrasound, functional MRI and MRI of the levator muscles. The closing sections of the book describe the modern clinical management of pelvic floor dysfunction, including prolapse, urinary and faecal incontinence and constipation, with specific emphasis on the integration of diagnostic and treatment algorithms. (orig.)

  8. Imaging pelvic floor disorders. 2. rev. ed.

    Energy Technology Data Exchange (ETDEWEB)

    Stoker, Jaap [Amsterdam Univ. (Netherlands). Dept. of Radiology; Taylor, Stuart A. [University College Hospital, London (United Kingdom). Dept. of Specialist X-Ray; DeLancey, John O.L. (eds.) [Michigan Univ., Ann Arbor, MI (United States). L4000 Women' s Hospital

    2008-07-01

    This volume builds on the success of the first edition of imaging pelvic floor disorders and is aimed at those practitioners with an interest in the imaging, diagnosis and treatment of pelvic floor dysfunction. Concise textual information from acknowledged experts is complemented by high-quality diagrams and images to provide a thorough update of this rapidly evolving field. Introductory chapters fully elucidate the anatomical basis underlying disorders of the pelvic floor. State of the art imaging techniques and their application in pelvic floor dysfunction are then discussed in detail. Additions since the first edition include consideration of the effect of aging and new chapters on perineal ultrasound, functional MRI and MRI of the levator muscles. The closing sections of the book describe the modern clinical management of pelvic floor dysfunction, including prolapse, urinary and faecal incontinence and constipation, with specific emphasis on the integration of diagnostic and treatment algorithms. (orig.)

  9. Floor heating maximizes residents` comfort

    Energy Technology Data Exchange (ETDEWEB)

    Tirkkanen, P.; Wikstroem, T.

    1996-11-01

    Storing heat in floors by using economical night-time electricity does not increase the specific consumption of heating. According to studies done by IVO, the optimum housing comfort is achieved if the room is heated mainly by means of floor heating that is evened out by window or ceiling heating, or by a combination of all three forms of heating. (orig.)

  10. Cosmological horizons as new examples of the membrane paradigm

    International Nuclear Information System (INIS)

    Wang, Tower

    2015-01-01

    In this paper we aim to provide new examples of the application and the generality of the membrane paradigm. The membrane paradigm is a formalism for studying the event horizon of black holes. After analyzing it with some technical details and realizing it in the Reissner–Nordström black hole, we apply the paradigm to cosmological horizons, first to the pure de Sitter horizon, and then to the trapping horizon of the Friedmann–Lemaître–Robertson–Walker Universe. In the latter case, the cosmological stretched horizon is oblique, thus the running of the renormalization parameter is nonzero in the timelike direction and gives a correction to the membrane pressure. In this paradigm, the cosmological equations come from continuity equations of the membrane fluid and the bulk fluid respectively. (paper)

  11. 78 FR 30329 - Multilayered Wood Flooring from China

    Science.gov (United States)

    2013-05-22

    ...)] Multilayered Wood Flooring from China AGENCY: United States International Trade Commission. ACTION: Notice of...-1179 (Final) concerning multilayered wood flooring (``MLWF'') from China. For further information... reconsider ``its decision not to investigate domestic producers of hardwood plywood used for flooring'' 2. to...

  12. Pelvic floor function during and after first pregnancy

    NARCIS (Netherlands)

    Brummen, H.J. van

    2006-01-01

    This study evaluated the effects the first pregnancy and childbirth on the pelvic floor. Pregnancy and vaginal delivery can negatively affect pelvic floor function. Micturition symptoms, defecation symptoms and sexual dysfunction are all signs of an impaired pelvic floor function. These symptoms are

  13. Gait of dairy cows on floors with different slipperiness.

    Science.gov (United States)

    Telezhenko, E; Magnusson, M; Bergsten, C

    2017-08-01

    This study assessed the slip resistance of different types of solid flooring in cattle housing using a range of technical tests and gait analysis. Dynamic and static coefficient of friction, skid resistance, and abrasiveness were tested on concrete flooring with a smooth finish, a grooved pattern, or a tamped pattern, acid-resistant mastic asphalt, soft rubber mats, and a worn slatted concrete floor. Coefficients of friction and skid resistance were tested under clean and slurry-soiled conditions. Linear kinematic variables were assessed in 40 cows with trackway measurements after the cows passed over the floors in a straight walk. All gait variables were assessed as deviations from those obtained on the slatted concrete floor, which was used as a baseline. The coefficient of friction tests divided the floors into 3 categories: concrete flooring, which had a low coefficient of friction (0.29-0.41); mastic asphalt flooring, which had medium values (0.38-0.45); and rubber mats, which had high values (0.49-0.57). The highest abrasion (g/10 m) was on the asphalt flooring (4.48), and the concrete flooring with a tamped pattern had significantly higher abrasiveness (2.77) than the other concrete floors (1.26-1.60). Lowest values on the skid-resistance tests (dry/wet) were for smooth concrete (79/35) and mastic asphalt (65/47), especially with a slurry layer on the surface. Gait analysis mainly differentiated floors with higher friction and abrasion by longer strides and better tracking. Step asymmetry was lower on floors with high skid-resistance values. The most secure cow gait, in almost every aspect, was observed on soft rubber mats. Relationships between gait variables and physical floor characteristics ranged from average to weak (partial correlations 0.54-0.16). Thus, none of the physical characteristics alone was informative enough to characterize slip resistance. With reference to gait analysis, the abrasiveness of the hard surfaces was more informative than the

  14. Mapping of multi-floor buildings: A barometric approach

    DEFF Research Database (Denmark)

    Özkil, Ali Gürcan; Fan, Zhun; Xiao, Jizhong

    2011-01-01

    This paper presents a new method for mapping multi5floor buildings. The method combines laser range sensor for metric mapping and barometric pressure sensor for detecting floor transitions and map segmentation. We exploit the fact that the barometric pressure is a function of the elevation......, and it varies between different floors. The method is tested with a real robot in a typical indoor environment, and the results show that physically consistent multi5floor representations are achievable....

  15. Gross changes in forest area shape the future carbon balance of tropical forests

    Directory of Open Access Journals (Sweden)

    W. Li

    2018-01-01

    Full Text Available Bookkeeping models are used to estimate land-use and land-cover change (LULCC carbon fluxes (ELULCC. The uncertainty of bookkeeping models partly arises from data used to define response curves (usually from local data and their representativeness for application to large regions. Here, we compare biomass recovery curves derived from a recent synthesis of secondary forest plots in Latin America by Poorter et al. (2016 with the curves used previously in bookkeeping models from Houghton (1999 and Hansis et al. (2015. We find that the two latter models overestimate the long-term (100 years vegetation carbon density of secondary forest by about 25 %. We also use idealized LULCC scenarios combined with these three different response curves to demonstrate the importance of considering gross forest area changes instead of net forest area changes for estimating regional ELULCC. In the illustrative case of a net gain in forest area composed of a large gross loss and a large gross gain occurring during a single year, the initial gross loss has an important legacy effect on ELULCC so that the system can be a net source of CO2 to the atmosphere long after the initial forest area change. We show the existence of critical values of the ratio of gross area change over net area change (γAnetAgross, above which cumulative ELULCC is a net CO2 source rather than a sink for a given time horizon after the initial perturbation. These theoretical critical ratio values derived from simulations of a bookkeeping model are compared with observations from the 30 m resolution Landsat Thematic Mapper data of gross and net forest area change in the Amazon. This allows us to diagnose areas in which current forest gains with a large land turnover will still result in LULCC carbon emissions in 20, 50 and 100 years.

  16. The absence of horizon in black-hole formation

    Energy Technology Data Exchange (ETDEWEB)

    Ho, Pei-Ming, E-mail: pmho@phys.ntu.edu.tw

    2016-08-15

    With the back-reaction of Hawking radiation taken into consideration, the work of Kawai, Matsuo and Yokokura [1] has shown that, under a few assumptions, the collapse of matter does not lead to event horizon nor apparent horizon. In this paper, we relax their assumptions and elaborate on the space-time geometry of a generic collapsing body with spherical symmetry. The geometry outside the collapsing sphere is found to be approximated by the geometry outside the white-hole horizon, hence the collapsing matter remains outside the Schwarzschild radius. As particles in Hawking radiation are created in the vicinity of the collapsing matter, the information loss paradox is alleviated. Assuming that the collapsing body evaporates within finite time, there is no event horizon.

  17. The absence of horizon in black-hole formation

    Directory of Open Access Journals (Sweden)

    Pei-Ming Ho

    2016-08-01

    Full Text Available With the back-reaction of Hawking radiation taken into consideration, the work of Kawai, Matsuo and Yokokura [1] has shown that, under a few assumptions, the collapse of matter does not lead to event horizon nor apparent horizon. In this paper, we relax their assumptions and elaborate on the space-time geometry of a generic collapsing body with spherical symmetry. The geometry outside the collapsing sphere is found to be approximated by the geometry outside the white-hole horizon, hence the collapsing matter remains outside the Schwarzschild radius. As particles in Hawking radiation are created in the vicinity of the collapsing matter, the information loss paradox is alleviated. Assuming that the collapsing body evaporates within finite time, there is no event horizon.

  18. The absence of horizon in black-hole formation

    International Nuclear Information System (INIS)

    Ho, Pei-Ming

    2016-01-01

    With the back-reaction of Hawking radiation taken into consideration, the work of Kawai, Matsuo and Yokokura [1] has shown that, under a few assumptions, the collapse of matter does not lead to event horizon nor apparent horizon. In this paper, we relax their assumptions and elaborate on the space-time geometry of a generic collapsing body with spherical symmetry. The geometry outside the collapsing sphere is found to be approximated by the geometry outside the white-hole horizon, hence the collapsing matter remains outside the Schwarzschild radius. As particles in Hawking radiation are created in the vicinity of the collapsing matter, the information loss paradox is alleviated. Assuming that the collapsing body evaporates within finite time, there is no event horizon.

  19. Estimation of In-canopy Flux Distributions of Reactive Nitrogen and Sulfur within a Mixed Hardwood Forest in Southern Appalachia

    Science.gov (United States)

    Wu, Z.; Walker, J. T.; Chen, X.; Oishi, A. C.; Duman, T.

    2017-12-01

    Estimating the source/sink distribution and vertical fluxes of air pollutants within and above forested canopies is critical for understanding biological, physical, and chemical processes influencing the soil-vegetation-atmosphere exchange. The vertical source-sink profiles of reactive nitrogen and sulfur were examined using multiple inverse modeling methods in a mixed hardwood forest in the southern Appalachian Mountains where the ecosystem is highly sensitive to loads of pollutant from atmospheric depositions. Measurements of the vertical concentration profiles of ammonia (NH3), nitric acid (HNO3), sulfur dioxide (SO2), and ammonium (NH4+), nitrate (NO3-), and sulfate (SO42-) in PM2.5 were measured during five study periods between May 2015 and August 2016. The mean concentration of NH3 decreased with height in the upper canopy and increased below the understory toward the forest floor, indicating that the canopy was a sink for NH3 but the forest floor was a source. All other species exhibited patterns of monotonically decreasing concentration from above the canopy to the forest floor. Using the measured concentration profiles, we simulated the within-canopy flow fields and estimated the vertical source-sink flux profiles using three inverse approaches: a Eulerian high-order closure model (EUL), a Lagrangian localized near-field (LNF) model, and a new full Lagrangian stochastic model (LSM). The models were evaluated using the within- and above-canopy eddy covariance flux measurements of heat, CO2 and H2O. Differences between models were analyzed and the flux profiles were used to investigate the origin and fate of reactive nitrogen and sulfur compounds within the canopy. The knowledge gained in this study will benefit the development of soil-vegetation-atmosphere models capable of partitioning canopy-scale deposition of nitrogen and sulfur to specific ecosystem compartments.

  20. Some Passive Damping Sources on Flooring Systems besides the TMD

    DEFF Research Database (Denmark)

    Pedersen, Lars

    2010-01-01

    Impulsive loads and walking loads can generate problematic structural vibrations in flooring-systems. Measures that may be taken to mitigate the problem would often be to consider the implementation of a tuned mass damper or even more advanced vibration control technologies; this in order to add...... damping to the structure. Basically also passive humans on a floor act as a damping source, but it also turns out from doing system identification tests with a floor strip that a quite simple set-up installed on the floor (cheap and readily at hand) might do a good job in terms of reducing vertical floor...... vibrations for some floors. The paper describes the tests with the floor strip, and the results, in terms of dynamic floor behaviour, are compared with what would be expected had the floor instead been equipped with a tuned mass damper....

  1. Transfer of radio-cesium from forest soil to woodchips using fungal activities

    Science.gov (United States)

    Kaneko, Nobuhiro; Huang, Yao; Tanaka, Yoichiro; Fujiwara, Yoshihiro; Sasaki, Michiko; Toda, Hiroto; Takahashi, Terumasa; Kobayashi, Tatsuaki; Harada, Naoki; Nonaka, Masahiro

    2014-05-01

    Raido-cesium released to terrestrial ecosystems by nuclear accidents is know to accumulate forest soil and organic layer on the soil. Forests in Japan are not exceptions. Practically it is impossible to decontaminate large area of forests. However, there is a strong demand from local people, who has been using secondary forests (Satoyama) around croplands in hilly areas, to decontaminate radio-cesium, because those people used to collect wild mushrooms and edible plants, and there are active cultures of mushrooms using logs and sawdusts. These natural resource uses consist substantial part of their economical activities, Therefore it is needed to decontaminate some selected part of forests in Japan to local economy. Clear cutting and scraping surface soil and organic matter are common methods of decontamination. However the efficiency of decontamination is up to 30% reduction of aerial radiation, and the cost to preserve contaminated debris is not affordable. In this study we used wood chips as a growth media for saprotrophic fungi which are known to accumulate redio-cesium. There are many studies indicated that mushrooms accumulated redio-cesium from forest soil and organic layer. It is not practical to collect mushrooms to decontaminate redio-cesium, because biomass of mushrooms are not enough to collect total contaminants. Mushrooms are only minor part of saprotrophic fungi. Fungal biomass in forest soil is about 1% of dead organic matter on forest floor. Our previous study to observe Cs accumulation to decomposing leaf litter indicated 18% absorption of total soil radio-Cs to litter during one year field incubation (Kaneko et al., 2013), and Cs concentration was proportional to fungal biomass on litter. This result indicated that fungi transferred radio-cesium around newly supplied leaf litter free of contamination. Therefore effective decontamination will be possible if we can provide large amount of growth media for saprotrophic fungi, and the media can be

  2. Beyond the veil: Inner horizon instability and holography

    International Nuclear Information System (INIS)

    Balasubramanian, Vijay; Levi, Thomas S.

    2004-01-01

    We show that scalar perturbations of the eternal, rotating Banados-Teitelboim-Zanelli (BTZ) black hole should lead to an instability of the inner (Cauchy) horizon, preserving strong cosmic censorship. Because of backscattering from the geometry, plane-wave modes have a divergent stress tensor at the event horizon, but suitable wave packets avoid this difficulty, and are dominated at late times by quasinormal behavior. The wave packets have cuts in the complexified coordinate plane that are controlled by requirements of continuity, single-valuedness, and positive energy. Due to a focusing effect, regular wave packets nevertheless have a divergent stress energy at the inner horizon, signaling an instability. We propose that this instability, which is localized behind the event horizon, is detected holographically as a breakdown in the semiclassical computation of dual conformal field theory (CFT) expectation values in which the analytic behavior of wave packets in the complexified coordinate plane plays an integral role. In the dual field theory, this is interpreted as an encoding of physics behind the horizon in the entanglement between otherwise independent CFTs

  3. Signature for the absence of an event horizon

    International Nuclear Information System (INIS)

    Barbieri, James; Chapline, George

    2012-01-01

    One of the most celebrated predictions of general relativity is that compact astrophysical objects with masses greater than a few solar masses are surrounded by an event horizon where time stands still and communication from the interior to the exterior is cutoff. Despite profound theoretical reasons for doubting whether an event horizon is physically possible, no definitive test as to whether event horizons really exist has yet been proposed. In this Letter we propose an experimental signature for the non-existence of event horizons. In particular we point out that a sharp dip in the spectrum of π 0 decay gamma rays below 70 MeV coming from compact objects with masses exceeding a few solar masses would be definitive evidence that these objects have a physical surface and there is no event horizon. Observation of such gamma rays would also for the first time open an experimental window on physical processes at energies near to the Planck scale. The prospects for seeing the 70 MeV feature in the near future are briefly discussed.

  4. Life cycle inventory of manufacturing prefinished engineered wood flooring in eastern U.S. with comparison to solid strip wood flooring

    Science.gov (United States)

    Richard D. Bergman; Scott A. Bowe

    2011-01-01

    Building products have come under increased scrutiny because of environmental impacts from their manufacture. Our study followed the life cycle inventory approach for prefinished engineered wood flooring in the eastern US and compared the results with those of solid strip wood flooring. Our study surveyed five engineered wood flooring manufacturers in the eastern US....

  5. Experimental Verification of an Instrument to Test Flooring Materials

    Science.gov (United States)

    Philip, Rony; Löfgren, Hans, Dr

    2018-02-01

    The focus of this work is to validate the fluid model with different flooring materials and the measurements of an instrument to test flooring materials and its force attenuating capabilities using mathematical models to describe the signature and coefficients of the floor. The main contribution of the present work focus on the development of a mathematical fluid model for floors. The aim of the thesis was to analyze, compare different floor materials and to study the linear dynamics of falling impacts on floors. The impact of the hammer during a fall is captured by an accelerometer and response is collected using a picoscope. The collected data was analyzed using matlab least square method which is coded as per the fluid model. The finding from this thesis showed that the fluid model works with more elastic model but it doesn’t work for rigid materials like wood. The importance of parameters like velocity, mass, energy loss and other coefficients of floor which influences the model during the impact of falling on floors were identified and a standardized testing method was set.

  6. Hawking radiation of an apparent horizon in a FRW universe

    International Nuclear Information System (INIS)

    Cai Ronggen; Cao Liming; Hu Yapeng

    2009-01-01

    Hawking radiation is an important quantum phenomenon of a black hole, which is closely related to the existence of an event horizon of a black hole. The cosmological event horizon of de Sitter space is also of Hawking radiation with a thermal spectrum. By use of the tunneling approach, we show that there is indeed a Hawking radiation with temperature, T=1/(2πr-tilde A , for a locally defined apparent horizon of a Friedmann-Robertson-Walker universe with any spatial curvature, where r-tilde A is the apparent horizon radius. Thus we fill in the gap existing in the literature investigating the relation between the first law of thermodynamics and Friedmann equations; there the apparent horizon is assumed to have such a temperature without any proof. In addition, we stress the implication of the Hawking temperature associated with the apparent horizon.

  7. The role of fungi in the transfer and cycling of radionuclides in forest ecosystems

    International Nuclear Information System (INIS)

    Steiner, M.; Linkov, I.; Yoshida, S.

    2002-01-01

    Fungi are one of the most important components of forest ecosystems, since they determine to a large extent the fate and transport processes of radionuclides in forests. They play a key role in the mobilization, uptake and translocation of nutrients and are likely to contribute substantially to the long-term retention of radiocesium in organic horizons of forest soil. This paper gives an overview of the role of fungi regarding the transfer and cycling of nutrients and radionuclides, with special emphasis on mycorrhizal symbiosis. Common definitions of transfer factors, soil-fungus and soil-green plant, including their advantages and limitations, are reviewed. Experimental approaches to quantify the bioavailability of radionuclides in soil and potential long-term change are discussed

  8. The role of fungi in the transfer and cycling of radionuclides in forest ecosystems

    Energy Technology Data Exchange (ETDEWEB)

    Steiner, M. E-mail: msteiner@bfs.de; Linkov, I.; Yoshida, S

    2002-07-01

    Fungi are one of the most important components of forest ecosystems, since they determine to a large extent the fate and transport processes of radionuclides in forests. They play a key role in the mobilization, uptake and translocation of nutrients and are likely to contribute substantially to the long-term retention of radiocesium in organic horizons of forest soil. This paper gives an overview of the role of fungi regarding the transfer and cycling of nutrients and radionuclides, with special emphasis on mycorrhizal symbiosis. Common definitions of transfer factors, soil-fungus and soil-green plant, including their advantages and limitations, are reviewed. Experimental approaches to quantify the bioavailability of radionuclides in soil and potential long-term change are discussed.

  9. Black hole entropy, universality, and horizon constraints

    International Nuclear Information System (INIS)

    Carlip, Steven

    2006-01-01

    To ask a question about a black hole in quantum gravity, one must restrict initial or boundary data to ensure that a black hole is actually present. For two-dimensional dilaton gravity, and probably a much wider class of theories, I show that the imposition of a 'stretched horizon' constraint modifies the algebra of symmetries at the horizon, allowing the use of conformal field theory techniques to determine the asymptotic density of states. The result reproduces the Bekenstein-Hawking entropy without any need for detailed assumptions about the microscopic theory. Horizon symmetries may thus offer an answer to the problem of universality of black hole entropy

  10. Black hole entropy, universality, and horizon constraints

    Energy Technology Data Exchange (ETDEWEB)

    Carlip, Steven [Department of Physics, University of California, Davis, CA 95616 (United States)

    2006-03-01

    To ask a question about a black hole in quantum gravity, one must restrict initial or boundary data to ensure that a black hole is actually present. For two-dimensional dilaton gravity, and probably a much wider class of theories, I show that the imposition of a 'stretched horizon' constraint modifies the algebra of symmetries at the horizon, allowing the use of conformal field theory techniques to determine the asymptotic density of states. The result reproduces the Bekenstein-Hawking entropy without any need for detailed assumptions about the microscopic theory. Horizon symmetries may thus offer an answer to the problem of universality of black hole entropy.

  11. Environmental fate and distribution of technetium-99 in a deciduous forest ecosystem

    International Nuclear Information System (INIS)

    Garten, C.T. Jr.; Tucker, C.S.; Walton, B.T.

    1986-01-01

    The uptake of 99 Tc by trees intercepting contaminated groundwater from a radioactive waste storage site was measured to identify the major 99 Tc pools within the woodland ecosystem and to assess the relative mobility of 99 Tc in the existing element cycle. The highest average 99 Tc concentrations in vegetation were found in herbaceous plants. Tree wood was the major above-ground pool for 99 Tc because of the high concentrations in wood as well as the large amount of wood relative to other biomass at the site. Technetium was not easily leached from the trees by rainfall and was not readily extractable from forest floor leaf litter by water. The relative importance of return pathways for 99 Tc to the forest floor was leaf fall > stemflow > throughfall, indicating that 99 Tc was conserved by the trees. Snails and millipedes from the leaf litter layer concentrated technetium 20- and 16-fold, respectively, above levels found in the soil. Pertechnetate was rendered less bioavailable after ingestion by a leaf litter macroinvertebrate (Porcellio sp.) common to the study site. (author)

  12. The NMC Horizon Report: 2015 Museum Edition

    Science.gov (United States)

    Johnson, L.; Adams Becker, S.; Estrada, V.; Freeman, A.

    2015-01-01

    The internationally recognized series of "Horizon Reports" is part of the New Media Consortium's Horizon Project, a comprehensive research venture established in 2002 that identifies and describes emerging technologies likely to have a large impact over the coming years on a variety of sectors around the globe. This "2015 Horizon…

  13. Patients with Pelvic Floor Muscle Spasm Have a Superior Response to Pelvic Floor Physical Therapy at Specialized Centers.

    Science.gov (United States)

    Polackwich, Alan Scott; Li, Jianbo; Shoskes, Daniel A

    2015-10-01

    Chronic prostatitis/chronic pelvic pain syndrome is a common condition that often requires multimodal therapy. Patients with chronic pelvic pain syndrome have a high incidence of pelvic floor spasm, which can be treated with pelvic floor physical therapy. However, this is a specialized skill. We compared outcomes of pelvic floor physical therapy as part of multimodal therapy in patients with chronic pelvic pain syndrome between those treated at our institution and elsewhere. We identified patients from our chronic pelvic pain syndrome registry with pelvic floor spasm who were seen between 2010 and 2014 for more than 1 visit. Patient phenotype was assessed with the UPOINT system and symptom severity was determined by the National Institutes of Health CPSI. A 6-point decrease in CPSI was used to define patient improvement. A total of 82 patients fit the study criteria. Mean age was 41.6 years (range 19 to 75) and median symptom duration was 24 months (range 3 to 240). Mean CPSI was 26.8 (range 10 to 41), the median number of positive UPOINT domains was 3 (range 1 to 6) and 27 patients (32.9%) were treated locally. At followup 9 patients had refused pelvic floor physical therapy, and 24 and 48 had undergone pelvic floor physical therapy elsewhere and at CCF, respectively. The mean change in CPSI was 1.11 ± 4.1 in patients who refused, -3.46 ± 6.7 in those treated elsewhere and -11.3 ± 7.0 in those treated at CCF (p physical therapy at CCF (OR 4.23, p = 0.002) and symptom duration (OR 0.52, p = 0.03) predicted improvement. Pelvic floor physical therapy can be effective for chronic pelvic pain syndrome in patients with pelvic floor spasm. However, the outcome depends on specialty training and experience of therapists. Copyright © 2015 American Urological Association Education and Research, Inc. Published by Elsevier Inc. All rights reserved.

  14. Investigation of Floor Surface Finishes for Optimal Slip Resistance Performance

    Directory of Open Access Journals (Sweden)

    In-Ju Kim

    2018-03-01

    Full Text Available Background: Increasing the slip resistance of floor surfaces would be desirable, but there is a lack of evidence on whether traction properties are linearly correlated with the topographic features of the floor surfaces or what scales of surface roughness are required to effectively control the slipperiness of floors. Objective: This study expands on earlier findings on the effects of floor surface finishes against slip resistance performance and determines the operative ranges of floor surface roughness for optimal slip resistance controls under different risk levels of walking environments. Methods: Dynamic friction tests were conducted among three shoes and nine floor specimens under wet and oily environments and compared with a soapy environment. Results: The test results showed the significant effects of floor surface roughness on slip resistance performance against all the lubricated environments. Compared with the floor-type effect, the shoe-type effect on slip resistance performance was insignificant against the highly polluted environments. The study outcomes also indicated that the oily environment required rougher surface finishes than the wet and soapy ones in their lower boundary ranges of floor surface roughness. Conclusion: The results of this study with previous findings confirm that floor surface finishes require different levels of surface coarseness for different types of environmental conditions to effectively manage slippery walking environments. Collected data on operative ranges of floor surface roughness seem to be a valuable tool to develop practical design information and standards for floor surface finishes to efficiently prevent pedestrian fall incidents. Keywords: floor surface finishes, operational levels of floor surface roughness, slip resistance, wet, soapy and oily environments

  15. An architecture for agile shop floor control systems

    DEFF Research Database (Denmark)

    Langer, Gilad; Alting, Leo

    2000-01-01

    as shop floor control. This paper presents the Holonic Multi-cell Control System (HoMuCS) architecture that allows for design and development of holonic shop floor control systems. The HoMuCS is a shop floor control system which is sometimes referred to as a manufacturing execution system...

  16. Climate Warming Can Increase Soil Carbon Fluxes Without Decreasing Soil Carbon Stocks in Boreal Forests

    Science.gov (United States)

    Ziegler, S. E.; Benner, R. H.; Billings, S. A.; Edwards, K. A.; Philben, M. J.; Zhu, X.; Laganiere, J.

    2016-12-01

    Ecosystem C fluxes respond positively to climate warming, however, the net impact of changing C fluxes on soil organic carbon (SOC) stocks over decadal scales remains unclear. Manipulative studies and global-scale observations have informed much of the existing knowledge of SOC responses to climate, providing insights on relatively short (e.g. days to years) and long (centuries to millennia) time scales, respectively. Natural climate gradient studies capture integrated ecosystem responses to climate on decadal time scales. Here we report the soil C reservoirs, fluxes into and out of those reservoirs, and the chemical composition of inputs and soil organic matter pools along a mesic boreal forest climate transect. The sites studied consist of similar forest composition, successional stage, and soil moisture but differ by 5.2°C mean annual temperature. Carbon fluxes through these boreal forest soils were greatest in the lowest latitude regions and indicate that enhanced C inputs can offset soil C losses with warming in these forests. Respiration rates increased by 55% and the flux of dissolved organic carbon from the organic to mineral soil horizons tripled across this climate gradient. The 2-fold increase in litterfall inputs to these soils coincided with a significant increase in the organic horizon C stock with warming, however, no significant difference in the surface mineral soil C stocks was observed. The younger mean age of the mineral soil C ( 70 versus 330 YBP) provided further evidence for the greater turnover of SOC in the warmer climate soils. In spite of these differences in mean radiocarbon age, mineral SOC exhibited chemical characteristics of highly decomposed material across all regions. In contrast with depth trends in soil OM diagenetic indices, diagenetic shifts with latitude were limited to increases in C:N and alkyl to O-alkyl ratios in the overlying organic horizons in the warmer relative to the colder regions. These data indicate that the

  17. Fermions tunneling from apparent horizon of FRW universe

    International Nuclear Information System (INIS)

    Li Ran; Ren Jirong; Shi Dunfu

    2009-01-01

    In the paper [R.-G. Cai, L.-M. Cao, Y.-P. Hu, (arXiv: 0809.1554)], the scalar particles' Hawking radiation from the apparent horizon of Friedmann-Robertson-Walker (FRW) universe was investigated by using the tunneling formalism. They obtained the Hawking temperature associated with the apparent horizon, which was extensively applied in investigating the relationship between the first law of thermodynamics and Friedmann equations. In this Letter, we calculate fermions' Hawking radiation from the apparent horizon of FRW universe via tunneling formalism. Applying WKB approximation to the general covariant Dirac equation in FRW spacetime background, the radiation spectrum and Hawking temperature of apparent horizon are correctly recovered, which supports the arguments presented in the paper [R.-G. Cai, L.-M. Cao, Y.-P. Hu, (arXiv: 0809.1554)

  18. Transporting dynamics of radioactive cesium in a forest ecosystem and its discharge processes

    Energy Technology Data Exchange (ETDEWEB)

    Iseda, Kohei; Ohte, Nobuhito; Tanoi, Keitaro; Endo, Izuki; Oda, Tomoki; Kato, Hiroyu [Graduate School of Agricultural and Life Sciences, University of Tokyo (Japan)

    2014-07-01

    }Cs with open-rainfall, through-fall and stem-flow were monitored in each plot. {sup 137}Cs was not detected in open-rainfall. The through-fall {sup 137}Cs concentration of evergreen conifer stands tended to be higher than that of deciduous stands. There is large individual difference in stem-flow. These observed results suggest followings; 1) new atmospheric depositions of {sup 137}Cs is negligibly small 2) there is large amount of {sup 137}Cs which still attach to leaves or stems. We estimated movement flux of {sup 137}Cs from the canopy to the forest floor of to the forest. It was 6.07 Bq/(m{sup 2} day ) (2012/8/31-2013/4/19). In comparison between discharge flux of {sup 137}Cs from the forest and movement flux of {sup 137}Cs from the canopy to the forest floor, the latter was much higher than the former. This result implies that cesium is being accumulated in the forest floor. (authors)

  19. Falling through the black hole horizon

    International Nuclear Information System (INIS)

    Brustein, Ram; Medved, A.J.M.

    2015-01-01

    We consider the fate of a small classical object, a “stick”, as it falls through the horizon of a large black hole (BH). Classically, the equivalence principle dictates that the stick is affected by small tidal forces, and Hawking’s quantum-mechanical model of BH evaporation makes essentially the same prediction. If, on the other hand, the BH horizon is surrounded by a “firewall”, the stick will be consumed as it falls through. We have recently extended Hawking’s model by taking into account the quantum fluctuations of the geometry and the classical back-reaction of the emitted particles. Here, we calculate the strain exerted on the falling stick for our model. The strain depends on the near-horizon state of the Hawking pairs. We find that, after the Page time when the state of the pairs deviates significantly from maximal entanglement (as required by unitarity), the induced strain in our semiclassical model is still parametrically small. This is because the number of the disentangled pairs is parametrically smaller than the BH entropy. A firewall does, however, appear if the number of disentangled pairs near the horizon is of order of the BH entropy, as implicitly assumed in previous discussions in the literature.

  20. Comfort analysis of lightweight floor system

    NARCIS (Netherlands)

    Zegers, S.F.A.J.G.; Herwijnen, van F.; Randall, B.

    2007-01-01

    During the past 60 years, floor systems used in housing and office-buildings in the Netherlands were mostly made of concrete or other similar materials, These floor systems, which can be characterized as heavy, normally posed little problems concerning vibrations. In recent years, in light of

  1. Locating the Gribov horizon

    Energy Technology Data Exchange (ETDEWEB)

    Gao, Fei; Qin, Si-Xue; Roberts, Craig D.; Rodríguez-Quintero, Jose

    2018-02-01

    We explore whether a tree-level expression for the gluon two-point function, supposed to express effects of an horizon term introduced to eliminate the Gribov ambiguity, is consistent with the propagator obtained in simulations of lattice-regularised quantum chromodynamics (QCD). In doing so, we insist that the gluon two-point function obey constraints that ensure a minimal level of consistency with parton-like behaviour at ultraviolet momenta. In consequence, we are led to a position which supports a conjecture that the gluon mass and horizon scale are equivalent emergent massscales, each with a value of roughly 0.5 GeV; and wherefrom it appears plausible that the dynamical generation of a running gluon mass may alone be sufficient to remove the Gribov ambiguity.

  2. Locating the Gribov horizon

    Science.gov (United States)

    Gao, Fei; Qin, Si-Xue; Roberts, Craig D.; Rodríguez-Quintero, Jose

    2018-02-01

    We explore whether a tree-level expression for the gluon two-point function, supposed to express effects of an horizon term introduced to eliminate the Gribov ambiguity, is consistent with the propagator obtained in simulations of lattice-regularized quantum chromodynamics (QCD). In doing so, we insist that the gluon two-point function obey constraints that ensure a minimal level of consistency with parton-like behavior on the ultraviolet domain. In consequence, we are led to a position which supports a conjecture that the gluon mass and horizon scale are equivalent emergent mass-scales, each with a value of roughly 0.5 GeV; and wherefrom it appears plausible that the dynamical generation of a running gluon mass may alone be sufficient to remove the Gribov ambiguity.

  3. Deepwater Horizon Seafood Safety Response - Deepwater Horizon Oil Spill Seafood Safety Response

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — In the aftermath of the Deepwater Horizon oil spill in 2010, there was concern about the risk to human health through consumption of contaminated seafood from the...

  4. Membrane viewpoint on black holes: Dynamical electromagnetic fields near the horizon

    International Nuclear Information System (INIS)

    Macdonald, D.A.; Suen, W.

    1985-01-01

    This paper is part of a series of papers with the aim of developing a complete self-consistent formalism for the treatment of electromagnetic and gravitational fields in the neighborhood of a black-hole horizon. In this membrane formalism, the horizon is treated as a closed two-dimensional membrane lying in a curved three-dimensional space, and endowed with familiar physical properties such as entropy and temperature, surface pressure and viscosity, and electrical conductivity, charge, and current. This paper develops the concept of the ''stretched horizon,'' which will be vital for both the electromagnetic and gravitational aspects of the formalism, and it presents several model problems illustrating the interaction of dynamical electromagnetic fields with stationary black-hole horizons: The field of a test charge in various states of motion outside the Schwarzschild horizon is analyzed in the near-horizon limit, where the spatial curvature may be ignored and the metric may be approximated by that of Rindler. This analysis elucidates the influence of the horizon on the shapes and motions of electric and magnetic field lines when external agents move the field lines in arbitrary manners. It also illustrates how the field lines interact with the horizon's charge and current to produce an exchange of energy and momentum between the external agent and the horizon. A numerical calculation of the dynamical relaxation of a magnetic field threading a Schwarzschild black hole is also presented, illustrating the ''cleaning'' of a complicated field structure by a black-hole horizon, and elucidating the constraints on the location of the stretched horizon

  5. Floor Vibrations - as Induced and Reduced by Humans

    DEFF Research Database (Denmark)

    Pedersen, Lars

    . As for dynamic loads focus is placed on heel impact excitation and actions of jumping people causing floor vibrations. As for interaction between stationary humans and the vibrating floor focus is on modelling humans as oscillating spring-mass-damper systems attached to the floor rather than as simple added mass...

  6. Hawking radiation from the cosmological horizon in a FRW universe

    International Nuclear Information System (INIS)

    Hu Yapeng

    2011-01-01

    It is well known that there is a Hawking radiation from the cosmological horizon of the de Sitter spacetime, and the de Sitter spacetime can be a special case of a FRW universe. Therefore, there may be a corresponding Hawking radiation in a FRW universe. Indeed, there have been several clues showing that there is a Hawking radiation from the apparent horizon of a FRW universe. In our Letter, however, we find that the Hawking radiation may come from the cosmological horizon. Moreover, we also find that the Hawking radiation from the apparent horizon of a FRW universe in some previous works can be a special case in our result, and the condition is that the variation rate of cosmological horizon r . H is zero. Note that, this condition is also consistent with the underlying integrable condition in these works from the apparent horizon.

  7. The pedogeochemical segregation a few horizons in soils from glass houses

    Science.gov (United States)

    Bulgariu, Dumitru; Rusu, Constantin; Filipov, Feodor; Buzgar, Nicolae; Bulgariu, Laura

    2010-05-01

    Our studies have focused the apparition and manifestation conditions of pedogeochemical segregation phenomena in case of soils from Copou - Iaşi, Bacău and Bârlad (Romania) glass house, and the effects of this on the pedogeochemical and agrochemical characteristics of soils from glass houses cultivated with vegetables. The utilization of intensive cultivation technologies of vegetables in glass houses determined the degradation of morphological, physical and chemical characteristics of soils, by rapid evolution of salted processes (salinization and / or sodization), compaction, carbonatation, eluviation-illuviation, frangipane formation, stagnogleization, gleization etc. Under these conditions, at depth of 30-40 cm is formed a compact and impenetrable horizon - Ahok(x) horizon. In function of exploitation conditions and by the chemical-mineralogical characteristics of soils from glasshouses, the Ahok horizons can have frangipane properties, expressed more or less. These horizons determined a geochemical segregation of soils from glass houses: (i) superior horizons, above Ahok(x) horizon evolve in weak oxidative conditions, weak alkaline pH, higher salinity, humidity and temperature; (ii) inferior horizons, below Ahok(x) horizon evolve in weak reducing conditions weak acid pH, lower salinity, humidity and temperature. Concomitant with the development of Ahok(x) horizons, the rapid degradation of the properties of soils from glasshouses is observed. The aspects about the formation of frangipane horizon in soils from glasshouses are not yet sufficiently know. Whatever of the formation processes, the frangipane horizons determined a sever segregation in pedogeochemical evolution of soils from glass houses, with very important consequences on the agrochemical quality of these soils. The segregation effects are manifested in the differential dynamics of pedogeochemical processes from superior horizons (situated above the segregation horizon), in comparison with the

  8. Flooring-systems and their interaction with furniture and humans

    DEFF Research Database (Denmark)

    Frier, Christian; Pedersen, Lars; Andersen, Lars Vabbersgaard

    2017-01-01

    Flooring-system designs may be sensitive in terms of their vibrational performance due the risk that serviceability-limit-state problems may be encountered. For evaluating the vibrational performance of a flooring system at the design stage, decisions must be made by the engineer in charge...... of computations. Passive humans and/or furniture are often present on a floor. Typically, these masses and their way of interacting with the floor mass are ignored in predictions of vibrational behaviour of the flooring system. Utilizing a shell finite-element model, the paper explores and quantifies how non......-structural mass can influence central parameters describing the dynamic behaviour of the flooring system with focus on elevated non-structural mass. © 2017 The Authors. Published by Elsevier Ltd....

  9. Subjective Life Horizon and Portfolio Choice

    OpenAIRE

    Spaenjers , Christophe; Spira, Sven Michael

    2013-01-01

    Using data from a U.S. household survey, we examine the empirical relation between subjective life horizon (i.e., the self-reported expectation of remaining life span) and portfolio choice. We find that equity portfolio shares are higher for investors with longer horizons, ceteris paribus, in line with theoretical predictions. This result is robust to controlling for optimism and health status, accounting for the endogeneity of equity market participation, or instrumenting subjective life hor...

  10. Leaf Area Index (LAI Estimation of Boreal Forest Using Wide Optics Airborne Winter Photos

    Directory of Open Access Journals (Sweden)

    Pauline Stenberg

    2009-12-01

    Full Text Available A new simple airborne method based on wide optics camera is developed for leaf area index (LAI estimation in coniferous forests. The measurements are carried out in winter, when the forest floor is completely snow covered and thus acts as a light background for the hemispherical analysis of the images. The photos are taken automatically and stored on a laptop during the flights. The R2 value of the linear regression of the airborne and ground based LAI measurements was 0.89.

  11. Effect of variable soil texture, metal saturation of soil organic matter (SOM) and tree species composition on spatial distribution of SOM in forest soils in Poland.

    Science.gov (United States)

    Gruba, Piotr; Socha, Jarosław; Błońska, Ewa; Lasota, Jarosław

    2015-07-15

    In this study we investigated the effect of fine (ϕclay (FF) content in soils, site moisture, metal (Al and Fe) of soil organic matter (SOM) and forest species composition on the spatial distribution of carbon (C) pools in forest soils at the landscape scale. We established 275 plots in regular 200×200m grid in a forested area of 14.4km(2). Fieldwork included soil sampling of the organic horizon, mineral topsoil and subsoil down to 40cm deep. We analysed the vertical and horizontal distribution of soil organic carbon (SOC) stocks, as well as the quantity of physically separated fractions including the free light (fLF), occluded light (oLF) and mineral associated fractions (MAF) in the mineral topsoil (A, AE) horizons. Distribution of C in soils was predominantly affected by the variation in the FF content. In soils richer in the FF more SOC was accumulated in mineral horizons and less in the organic horizons. Accumulation of SOC in mineral soil was also positively affected by the degree of saturation of SOM with Al and Fe. The increasing share of beech influenced the distribution of C stock in soil profiles by reducing the depth of O horizon and increasing C stored in mineral soil. The content of FF was positively correlated with the content of C in MAF and fLF fractions. The content of oLF and MAF fractions was also positively influenced by a higher degree of metal saturation, particularly Al. Our results confirmed that Al plays an important role in the stabilization of SOM inside aggregates (CoLF) and as in CMAF fractions. We also found a significant, positive effect of beech on the CfLF and fir on the CoLF content. Copyright © 2015 Elsevier B.V. All rights reserved.

  12. Null infinity and extremal horizons in AdS-CFT

    International Nuclear Information System (INIS)

    Hickling, Andrew; Wiseman, Toby; Lucietti, James

    2015-01-01

    We consider AdS gravity duals to CFT on background spacetimes with a null infinity. Null infinity on the conformal boundary may extend to an extremal horizon in the bulk. For example it does so for Poincaré–AdS, although does not for planar Schwarzschild–AdS. If null infinity does extend into an extremal horizon in the bulk, we show that the bulk near-horizon geometry is determined by the geometry of the boundary null infinity. Hence the ‘infra-red’ geometry of the bulk is fixed by the large scale behaviour of the CFT spacetime. In addition the boundary stress tensor must have a particular decay at null infinity. As an application, we argue that for CFT on asymptotically flat backgrounds, any static bulk dual containing an extremal horizon extending from the boundary null infinity, must have the near-horizon geometry of Poincaré–AdS. We also discuss a class of boundary null infinity that cannot extend to a bulk extremal horizon, although we give evidence that they can extend to an analogous null surface in the bulk which possesses an associated scale-invariant ‘near-geometry’. (paper)

  13. On the membrane paradigm and spontaneous breaking of horizon BMS symmetries

    International Nuclear Information System (INIS)

    Eling, Christopher; Oz, Yaron

    2016-01-01

    We consider a BMS-type symmetry action on isolated horizons in asymptotically flat spacetimes. From the viewpoint of the non-relativistic field theory on a horizon membrane, supertranslations shift the field theory spatial momentum. The latter is related by a Ward identity to the particle number symmetry current and is spontaneously broken. The corresponding Goldstone boson shifts the horizon angular momentum and can be detected quantum mechanically. Similarly, area preserving superrotations are spontaneously broken on the horizon membrane and we identify the corresponding gapless modes. In asymptotically AdS spacetimes we study the BMS-type symmetry action on the horizon in a holographic superfluid dual. We identify the horizon supertranslation Goldstone boson as the holographic superfluid Goldstone mode.

  14. Development of floor design response spectra for seismic design of floor-supported equipment or components, Revision 1, February 1978

    International Nuclear Information System (INIS)

    Anon.

    1979-01-01

    This guide presents an acceptable method for developing two horizontal and one vertical floor design response spectra at various floor or other equipment-support locations from the time-history motions resulting from the dynamic analysis of the supporting structure. These floor design response spectra are used in the dynamic analysis of systems or equipment supported at various locations of the supporting structure. Consulation has been provided by the Advisory Committee on Reactor Safeguards

  15. Deflection of resilient materials for reduction of floor impact sound.

    Science.gov (United States)

    Lee, Jung-Yoon; Kim, Jong-Mun

    2014-01-01

    Recently, many residents living in apartment buildings in Korea have been bothered by noise coming from the houses above. In order to reduce noise pollution, communities are increasingly imposing bylaws, including the limitation of floor impact sound, minimum thickness of floors, and floor soundproofing solutions. This research effort focused specifically on the deflection of resilient materials in the floor sound insulation systems of apartment houses. The experimental program involved conducting twenty-seven material tests and ten sound insulation floating concrete floor specimens. Two main parameters were considered in the experimental investigation: the seven types of resilient materials and the location of the loading point. The structural behavior of sound insulation floor floating was predicted using the Winkler method. The experimental and analytical results indicated that the cracking strength of the floating concrete floor significantly increased with increasing the tangent modulus of resilient material. The deflection of the floating concrete floor loaded at the side of the specimen was much greater than that of the floating concrete floor loaded at the center of the specimen. The Winkler model considering the effect of modulus of resilient materials was able to accurately predict the cracking strength of the floating concrete floor.

  16. Decontamination of polyvinylchloride- and rubber type flooring

    International Nuclear Information System (INIS)

    Kunze, S.

    1975-01-01

    These types, fabricated by mixing of the basic components, showed no relation between content of fillers and decontamination results. Decontamination results are partly poorer, if the flooring contains a high concentration of the filler, especially if the latter consists mainly of hydrophilic materials. The coloring of the floorings seems to have no influence on the decontamination but floorings with clearly separated patterns can not be recommended for nuclear facilities. Fabricated by chemical reactions between polymeres, vulcanization materials and fillers, the decontamination results depend definitely from the proper choice of the filler. Flooring types, containing lampblack, graphite, kaoline, barium sulfate and titanium oxide are easy to decontamine. Again, increasing contents of hydrophilic filler cause a fall off in the decontamination results. (orig.) [de

  17. CFT/gravity correspondence on the isolated horizon

    Energy Technology Data Exchange (ETDEWEB)

    Ghosh, Amit, E-mail: amit.ghosh@saha.ac.in [Saha Institute of Nuclear Physics, 1/AF Bidhan Nagar, 700064 Kolkata (India); Pranzetti, Daniele, E-mail: daniele.pranzetti@gravity.fau.de [Institute for Quantum Gravity, University of Erlangen-Nürnberg (FAU), Staudtstrasse 7/B2, 91058 Erlangen (Germany)

    2014-12-15

    A quantum isolated horizon can be modelled by an SU(2) Chern–Simons theory on a punctured 2-sphere. We show how a local 2-dimensional conformal symmetry arises at each puncture inducing an infinite set of new observables localised at the horizon which satisfy a Kac–Moody algebra. By means of the isolated horizon boundary conditions, we represent the gravitational flux degrees of freedom in terms of the zero modes of the Kac–Moody algebra defined on the boundary of a punctured disk. In this way, our construction encodes a precise notion of CFT/gravity correspondence. The higher modes in the algebra represent new nongeometric charges which can be represented in terms of free matter field degrees of freedom. When computing the CFT partition function of the system, these new states induce an extra degeneracy factor, representing the density of horizon states at a given energy level, which reproduces the Bekenstein's holographic bound for an imaginary Immirzi parameter. This allows us to recover the Bekenstein–Hawking entropy formula without the large quantum gravity corrections associated with the number of punctures.

  18. Historical Cavern Floor Rise for All SPR Sites

    Energy Technology Data Exchange (ETDEWEB)

    Moriarty, Dylan Michael [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)

    2016-09-01

    The Strategic Petroleum Reserve (SPR) contains the largest supply is the largest stockpile of government-owned emergency crude oil in the world. The oil is stored in multiple salt caverns spread over four sites in Louisiana and Texas. Cavern infrastructure near the bottom of the cavern can be damaged from vertical floor movement. This report presents a comprehensive history of floor movements in each cavern. Most of the cavern floor rise rates ranged from 0.5-3.5 ft/yr, however, there were several caverns with much higher rise rates. BH103, BM106, and BH105 had the three highest rise rates. Information from this report will be used to better predict future vertical floor movements and optimally place cavern infrastructure. The reasons for floor rise are not entirely understood and should be investigated.

  19. Wider horizons, wiser choices: horizon scanning for public health protection and improvement.

    Science.gov (United States)

    Urquhart, Graham J; Saunders, Patrick

    2017-06-01

    Systematic continuous thinking about the future helps organizations, professions and communities to both prepare for, and shape, the future. This becomes ever more critical given the accelerating rate at which new data emerge, and in some cases uncertainties around their reliability and interpretation. Businesses with the capability to filter and analyse vast volumes of data to create knowledge and insights requiring action have a competitive advantage. Similarly Government and the public sector, including public health can be more effective and efficient through the early identification of emerging issues (both threats and opportunities). Horizon scanning approaches, and the use of resulting intelligence related to health protection and improvement were reviewed. Public health horizon scanning systems have to date focussed on health technologies and infectious diseases. While these have been successful there is a major gap in terms of non-infectious hazards and health improvement. Any system to meet this need must recognize the changed environment for delivering front line public health services and the critical role of local authorities and the local democratic process. This presents opportunities and challenges and this paper explores those dynamics describing an existing environment and health horizon scanning system which could readily and rapidly be re-engineered to provide a national service. © The Author 2016. Published by Oxford University Press on behalf of Faculty of Public Health. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

  20. Universality of P−V criticality in horizon thermodynamics

    Energy Technology Data Exchange (ETDEWEB)

    Hansen, Devin; Kubizňák, David [Perimeter Institute,31 Caroline St. N., Waterloo, Ontario, N2L 2Y5 (Canada); Department of Physics and Astronomy, University of Waterloo,Waterloo, Ontario, N2L 3G1 (Canada); Mann, Robert B. [Department of Physics and Astronomy, University of Waterloo,Waterloo, Ontario, N2L 3G1 (Canada)

    2017-01-11

    We study P−V criticality of black holes in Lovelock gravities in the context of horizon thermodynamics. The corresponding first law of horizon thermodynamics emerges as one of the Einstein-Lovelock equations and assumes the universal (independent of matter content) form δE=TδS−PδV, where P is identified with the total pressure of all matter in the spacetime (including a cosmological constant Λ if present). We compare this approach to recent advances in extended phase space thermodynamics of asymptotically AdS black holes where the ‘standard’ first law of black hole thermodynamics is extended to include a pressure-volume term, where the pressure is entirely due to the (variable) cosmological constant. We show that both approaches are quite different in interpretation. Provided there is sufficient non-linearity in the gravitational sector, we find that horizon thermodynamics admits the same interesting black hole phase behaviour seen in the extended case, such as a Hawking-Page transition, Van der Waals like behaviour, and the presence of a triple point. We also formulate the Smarr formula in horizon thermodynamics and discuss the interpretation of the quantity E appearing in the horizon first law.

  1. Universality of P−V criticality in horizon thermodynamics

    International Nuclear Information System (INIS)

    Hansen, Devin; Kubizňák, David; Mann, Robert B.

    2017-01-01

    We study P−V criticality of black holes in Lovelock gravities in the context of horizon thermodynamics. The corresponding first law of horizon thermodynamics emerges as one of the Einstein-Lovelock equations and assumes the universal (independent of matter content) form δE=TδS−PδV, where P is identified with the total pressure of all matter in the spacetime (including a cosmological constant Λ if present). We compare this approach to recent advances in extended phase space thermodynamics of asymptotically AdS black holes where the ‘standard’ first law of black hole thermodynamics is extended to include a pressure-volume term, where the pressure is entirely due to the (variable) cosmological constant. We show that both approaches are quite different in interpretation. Provided there is sufficient non-linearity in the gravitational sector, we find that horizon thermodynamics admits the same interesting black hole phase behaviour seen in the extended case, such as a Hawking-Page transition, Van der Waals like behaviour, and the presence of a triple point. We also formulate the Smarr formula in horizon thermodynamics and discuss the interpretation of the quantity E appearing in the horizon first law.

  2. Receding Horizon H∞ Control for Input-Delayed Systems

    Directory of Open Access Journals (Sweden)

    Han Woong Yoo

    2012-01-01

    Full Text Available We propose the receding horizon H∞ control (RHHC for input-delayed systems. A new cost function for a finite horizon dynamic game problem is first introduced, which includes two terminal weighting terms parameterized by a positive definite matrix, called a terminal weighing matrix. Secondly, the RHHC is obtained from the solution to the finite dynamic game problem. Thirdly, we propose an LMI condition under which the saddle point value satisfies the nonincreasing monotonicity. Finally, we show the asymptotic stability and H∞ boundedness of the closed-loop system controlled by the proposed RHHC. The proposed RHHC has a guaranteed H∞ performance bound for nonzero external disturbances and the quadratic cost can be improved by adjusting the prediction horizon length for nonzero initial condition and zero disturbance, which is not the case for existing memoryless state-feedback controllers. It is shown through a numerical example that the proposed RHHC is stabilizing and satisfies the infinite horizon H∞ performance bound. Furthermore, the performance in terms of the quadratic cost is shown to be improved by adjusting the prediction horizon length when there exists no external disturbance with nonzero initial condition.

  3. Association between preterm labour and pelvic floor muscle function.

    Science.gov (United States)

    Aran, Turhan; Pekgöz, Ipek; Bozkaya, Hasan; Osmanagaoglu, Mehmet A

    2018-03-23

    We hypothesised that the pressure on the cervix increases with advancing gestation and it may lead to a cervical shortening and cause preterm labour in women with weak pelvic floor muscles. The aim of this prospective study was to measure vaginal resting pressure and pelvic floor muscle strength in the first trimester of pregnancy and to investigate their effects on labour. A study was conducted on the pregnant women with a low risk for preterm birth. The pelvic floor muscle strength and vaginal resting pressure were assessed in 320 pregnant women at their first trimester with a vaginal pressure measurement device. Fifty-two pregnant women were hospitalised for tocolytic therapy because of spontaneous preterm labour. Thirty-two of them (10.2%) had a preterm delivery despite the tocolytic therapy. Both the vaginal resting pressure (p = .009, 95%CI: 0.8; 5.9) and the pelvic floor muscle strength (p = .01, 95%CI: 3.5; 13.1) were significantly lower in the women with a preterm labour. Impact statement What is already known on this subject? The pelvic floor muscles have an essential role in continence and provide support to the pelvic organs. They also have an impact on labour. The pelvic floor muscles should distend to allow the passage of the foetus during labour. The rotation and flexion of the foetal head is due to the pelvic floor resistance. The effect of a vaginal birth on the pelvic floor's function is readily understood. On the other hand, the effect of the pelvic floor muscle function on labour is still controversial. What do the results of this study add? This prospective study showed that there is a negative association between the pelvic floor muscle strength and preterm labour. This is the first clinical study indicating that weak pelvic floor muscles may cause a preterm labour. What are the implications of these findings for clinical practice and/or further research? Pelvic floor physical therapy may be an alternative preventive strategy to reduce

  4. Leafcutter Ant Nests Inhibit Low-Intensity Fire Spread in the Understory of Transitional Forests at the Amazon's Forest-Savanna Boundary

    Directory of Open Access Journals (Sweden)

    Karine S. Carvalho

    2012-01-01

    Full Text Available Leaf-cutter ants (Atta spp. remove leaf litter and woody debris—potential fuels—in and around their nests and foraging trails. We conducted single and three annual experimental fires to determine the effects of this leaf-cutter ant activity on the behavior of low-intensity, slow-moving fires. In a transitional forest, where the southern Amazon forest meets the Brazilian savanna, we tested whether leaf-cutter ant nests and trails (i inhibit fire spread due to a lack of fuels, and (ii, thereby, reduce the total burned area during these experimental low-intensity fires, particularly at forest edges where leaf-cutter ant abundance was higher. Fine-medium fuel mass increased with an increase in distance from ant nest, and the mean area of bare soil was greater on nests than on the forest floor. Between 60 to 90 percent of the unburned area was within 30 m of ant nests, and burned area significantly increased with increasing distance to ant nests. In addition, the number of ant nests declined with increasing distance from the forest edge, and, with exception of the first experimental fire, burned area also increased with increasing distance from the edge. The present study provides new insight to fire ecology in Amazon environments.

  5. Biomechanics of the pelvic floor musculature

    NARCIS (Netherlands)

    Janda, S.

    2006-01-01

    The present thesis was motivated by two main goals. The first research goal of the thesis was to understand the complex biomechanical behaviour of the pelvic floor muscles. The second goal was to study the mechanism of the pelvic organ prolapse (genital prolapse). The pelvic floor in humans is a

  6. Water cycle observations in forest watersheds of Cambodia

    Science.gov (United States)

    Shimizu, A.; Tamai, K.; Kabeya, N.; Shimizu, T.; Iida, S. I.

    2015-12-01

    The Lower Mekong River flows through Cambodia, where forests cover ~60% of the country and are believed to have a marked effect on the water cycle. These tropical seasonal forests in the Cambodian flat lands are very precious in the Indochinese Peninsula as few forests of this type remain. However, few hydrological observations have been conducted in these areas. In Cambodia, deciduous and evergreen forests make up 42% and 33% of the total forest area, respectively. We established experimental watersheds both in deciduous and evergreen forests containing meteorological observation towers in Cambodia and collected various observational data since 2003 (O'Krieng, deciduous forest watershed including a 30-m-high observation tower, 2,245 km2; Stung Chinit, evergreen forest watershed including a 60-m-high observation tower, 3,700 km2 including three small watersheds). The basic data from these sites included various kinds of information related to the composition of vegetation, soil characteristics, etc. Hydrologic data was collected and linked to the above data; the main hydrologic research results follow. The water budget for each watershed was determined using an observational rainfall and runoff dataset. The evapotranspiration rate in an evergreen forest was obtained using various observational methods including the Bowen energy-balance ratio and the bandpass eddy covariance method. The annual evapotranspiration of evergreen forests, estimated using the Bowen energy-balance ratio method and water balance, was about 1100-1200 mm, corresponding to 70-80% of annual rainfall. While considering the importance of the presence of evergreen forest, we conducted sap flow measurements to analyze the transpiration process that maintains water uptake through root systems that reach to depths exceeding 8 m. Characteristics of the evaporation from the forest floor that form an important element of the evaporation system were estimated in both evergreen and deciduous forests.

  7. Plant-cover influence on the spatial distribution of radiocaesium deposits in forest ecosystems

    International Nuclear Information System (INIS)

    Guillitte, Olivier; Andolina, Jean; Koziol, Michel; Debauche, Antoine

    1990-01-01

    Since the Chernobyl nuclear accident, a major campaign of radioactive deposit measurements has been carried out on forest soils in Belgium and the Grand Duchy of Luxemburg. Three types of forest ecosystems have systematically been taken into account in each region: coniferous forests (mainly spruce stands), deciduous forests (mainly beech stands) and in clearings. Sampling and field measurements have been carried out in different places with regard to the plant cover: near the trunks, under the foliage, in a small gap, on soil with or without herbaceous or moss stratum. The samples have been collected and measured according to the different recognizable soil layers in order to evaluate the vertical deposit distribution. From overall measurements, one may observe a high spatial soil deposit variation which is mainly explained by the nature, structure and age of the forest stands and by the thickness and the nature of holorganic horizons. A particular interest of this study is the identification of the influence of stem flow and impluvium on forest-cover gaps and edges. (author)

  8. Horizon thermodynamics in fourth-order gravity

    Directory of Open Access Journals (Sweden)

    Meng-Sen Ma

    2017-03-01

    Full Text Available In the framework of horizon thermodynamics, the field equations of Einstein gravity and some other second-order gravities can be rewritten as the thermodynamic identity: dE=TdS−PdV. However, in order to construct the horizon thermodynamics in higher-order gravity, we have to simplify the field equations firstly. In this paper, we study the fourth-order gravity and convert it to second-order gravity via a so-called “Legendre transformation” at the cost of introducing two other fields besides the metric field. With this simplified theory, we implement the conventional procedure in the construction of the horizon thermodynamics in 3 and 4 dimensional spacetime. We find that the field equations in the fourth-order gravity can also be written as the thermodynamic identity. Moreover, we can use this approach to derive the same black hole mass as that by other methods.

  9. Motor cortical representation of the pelvic floor muscles.

    Science.gov (United States)

    Schrum, A; Wolff, S; van der Horst, C; Kuhtz-Buschbeck, J P

    2011-07-01

    Pelvic floor muscle training involves rhythmical voluntary contractions of the external urethral sphincter and ancillary pelvic floor muscles. The representation of these muscles in the motor cortex has not been located precisely and unambiguously. We used functional magnetic resonance imaging to determine brain activity during slow and fast pelvic floor contractions. Cerebral responses were recorded in 17 healthy male volunteers, 21 to 47 years old, with normal bladder control. Functional magnetic resonance imaging was performed during metronome paced slow (0.25 Hertz) and fast (0.7 Hertz) contractions of the pelvic floor that mimicked the interruption of voiding. To study the somatotopy of the cortical representations, flexion-extension movements of the right toes were performed as a control task. Functional magnetic resonance imaging during pelvic floor contractions detected activity of the supplementary motor area in the medial wall and of the midcingulate cortex, insula, posterior parietal cortex, putamen, thalamus, cerebellar vermis and upper ventral pons. There were no significant differences in activation between slow and fast contractions. Toe movements involved significantly stronger activity of the paracentral lobule (ie the medial primary motor cortex) than did the pelvic floor contractions. Otherwise the areas active during pelvic floor and leg muscle contractions overlapped considerably. The motor cortical representation of pelvic floor muscles is located mostly in the supplementary motor area. It extends further ventrally and anteriorly than the representation of distal leg muscles. Copyright © 2011 American Urological Association Education and Research, Inc. Published by Elsevier Inc. All rights reserved.

  10. Thermal and nonthermal particle production without event horizons

    International Nuclear Information System (INIS)

    Sanchez, N.

    1979-01-01

    Usually, particle production in accelerated frames is discussed in connection with the presence of event horizons and with a planckian spectrum. Accelerated frames without event horizons, where particle production takes place with thermal as well as nonthermal distributions, are constructed. (Auth.)

  11. 9 CFR 91.26 - Concrete flooring.

    Science.gov (United States)

    2010-01-01

    ... 9 Animals and Animal Products 1 2010-01-01 2010-01-01 false Concrete flooring. 91.26 Section 91.26... LIVESTOCK FOR EXPORTATION Inspection of Vessels and Accommodations § 91.26 Concrete flooring. (a) Pens aboard an ocean vessel shall have a 3 inch concrete pavement, proportioned and mixed to give 2000 psi...

  12. Enhancement of Carbon Sequestration in west coast Douglas-fir Forests with Nitrogen Fertilization

    Science.gov (United States)

    Chen, B.; Jassal, R.; Black, A.; Brummer, C.; Spittlehouse, D.; Nesic, Z.

    2008-12-01

    Fertilization is one of the eligible management practices for C sequestering and hence reducing CO2 emissions under Article 3.4 of the Kyoto Protocol. In the coastal regions of British Columbia, which have very little nitrogen (N) deposition from pollution sources owing to their remote location, and soils deficient in N (Hanley et al., 1996), Douglas-fir stands respond to N fertilization (Brix, 1981; Fisher and Binkley, 2000; Chapin et al., 2002). However, a major concern with N fertilization is the potential loss from the soil surface of the highly potent greenhouse gas N2O, and little is known about such losses in N-fertilized forest soils. While it is necessary to determine and quantify the effects of N fertilization on stand C sequestration, it is also important to address environmental concerns by measuring N2O emissions to determine the net greenhouse gas (GHG) global warming potential (GWP). The GWP of N2O is 296 times (100-year time horizon) greater than that of CO2 (Ehhalt and Prather, 2001), yet there is little information on its net radiative forcing as a result of forest fertilization. We report two years of results on the effects of N fertilization in a chronosequence of three Douglas-fir stands (7, 19 and 58 years old, hereafter referred to as HDF00, HDF88 and DF49, respectively) on net C sequestration or net primary productivity measured using the eddy-covariance technique. DF49 (110 ha) and HDF88 (20 ha) were aerially fertilized with urea at 200 kg N ha-1 on Jan 13 and Feb 17, 2007, respectively, while due to its young age and competing understory, fertilizer to HDF00 (5 ha) was manually applied at 80 g urea/tree (60 kg N ha-1) along the tree drip line on Feb 13-14, 2007. Additionally, we calculate the net change in GHG GWP resulting from fertilization of DF49 by accounting for N2O emissions and energy costs of fertilizer production, transport, and application. We also compare polymer-coated slow-release urea (Environmentally Smart Nitrogen (ESN

  13. Effect of summer throughfall exclusion, summer drought, and winter snow cover on methane fluxes in a temperate forest soil

    Science.gov (United States)

    Borken, W.; Davidson, E.A.; Savage, K.; Sundquist, E.T.; Steudler, P.

    2006-01-01

    Soil moisture strongly controls the uptake of atmospheric methane by limiting the diffusion of methane into the soil, resulting in a negative correlation between soil moisture and methane uptake rates under most non-drought conditions. However, little is known about the effect of water stress on methane uptake in temperate forests during severe droughts. We simulated extreme summer droughts by exclusion of 168 mm (2001) and 344 mm (2002) throughfall using three translucent roofs in a mixed deciduous forest at the Harvard Forest, Massachusetts, USA. The treatment significantly increased CH4 uptake during the first weeks of throughfall exclusion in 2001 and during most of the 2002 treatment period. Low summertime CH4 uptake rates were found only briefly in both control and exclusion plots during a natural late summer drought, when water contents below 0.15 g cm-3 may have caused water stress of methanotrophs in the A horizon. Because these soils are well drained, the exclusion treatment had little effect on A horizon water content between wetting events, and the effect of water stress was smaller and more brief than was the overall treatment effect on methane diffusion. Methane consumption rates were highest in the A horizon and showed a parabolic relationship between gravimetric water content and CH4 consumption, with maximum rate at 0.23 g H2O g-1 soil. On average, about 74% of atmospheric CH4 was consumed in the top 4-5 cm of the mineral soil. By contrast, little or no CH4 consumption occurred in the O horizon. Snow cover significantly reduced the uptake rate from December to March. Removal of snow enhanced CH4 uptake by about 700-1000%, resulting in uptake rates similar to those measured during the growing season. Soil temperatures had little effect on CH4 uptake as long as the mineral soil was not frozen, indicating strong substrate limitation of methanotrophs throughout the year. Our results suggest that the extension of snow periods may affect the annual rate

  14. Surgical reconstruction of pelvic floor descent: anatomic and functional aspects.

    Science.gov (United States)

    Wagenlehner, F M E; Bschleipfer, T; Liedl, B; Gunnemann, A; Petros, P; Weidner, W

    2010-01-01

    The human pelvic floor is a complex structure and pelvic floor dysfunction is seen frequently in females. This review focuses on the surgical reconstruction of the pelvic floor employing recent findings on functional anatomy. A selective literature research was performed by the authors. Pelvic floor activity is regulated by 3 main muscular forces that are responsible for vaginal tension and suspension of the pelvic floor organs, bladder and rectum. A variety of symptoms can derive from pelvic floor dysfunctions, such as urinary urge and stress incontinence, abnormal bladder emptying, fecal incontinence, obstructive bowel disease syndrome and pelvic pain. These symptoms mainly derive, for different reasons, from laxity in the vagina or its supporting ligaments as a result of altered connective tissue. Pelvic floor reconstruction is nowadays driven by the concept that in case of pelvic floor symptoms, restoration of the anatomy will translate into restoration of the physiology and ultimately improve patients' symptoms. The surgical reconstruction of the anatomy is almost exclusively focused on the restoration of the lax pelvic floor ligaments. Exact preoperative identification of the anatomical lesions is necessary to allow for exact anatomical reconstruction with respect to the muscular forces of the pelvic floor. Copyright 2010 S. Karger AG, Basel.

  15. Forest Fire Finder - DOAS application to long-range forest fire detection

    Science.gov (United States)

    Valente de Almeida, Rui; Vieira, Pedro

    2017-06-01

    Fires are an important factor in shaping Earth's ecosystems. Plant and animal life, in almost every land habitat, are at least partially dependent on the effects of fire. However, their destructive force, which has often proven uncontrollable, is one of our greatest concerns, effectively resulting in several policies in the most important industrialised regions of the globe. This paper aims to comprehensively characterise the Forest Fire Finder (FFF), a forest fire detection system based mainly upon a spectroscopic technique called differential optical absorption spectroscopy (DOAS). The system is designed and configured with the goal of detecting higher-than-the-horizon smoke columns by measuring and comparing scattered sunlight spectra. The article covers hardware and software, as well as their interactions and specific algorithms for day mode operation. An analysis of data retrieved from several installations deployed in the course of the last 5 years is also presented. Finally, this paper features a discussion on the most prominent future improvements planned for the system, as well as its ramifications and adaptations, such as a thermal imaging system for short-range fire seeking or environmental quality control.

  16. Forest management strategies for reducing carbon emissions, the French case

    Science.gov (United States)

    Valade, Aude; Luyssaert, Sebastiaan; Bellassen, Valentin; Vallet, Patrick; Martin, Manuel

    2015-04-01

    International agreements now recognize the role of forest in the mitigation of climate change through the levers of in-situ sequestration, storage in products and energy and product substitution. These three strategies of carbon management are often antagonistic and it is still not clear which strategy would have the most significant impact on atmospheric carbon concentrations. With a focus on France, this study compares several scenarios of forest management in terms of their effect on the overall carbon budget from trees to wood-products. We elaborated four scenarios of forest management that target different wood production objectives. One scenario is 'Business as usual' and reproduces the current forest management and wood production levels. Two scenarios target an increase in bioenergy wood production, with either long-term or short-term goals. One scenario aims at increasing the production of timber for construction. For this, an empirical regression model was developed building on the rich French inventory database. The model can project the current forest resource at a time horizon of 20 years for characteristic variables diameter, standing volume, above-ground biomass, stand age. A simplified life-cycle analysis provides a full carbon budget for each scenario from forest management to wood use and allows the identification of the scenario that most reduces carbon emissions.

  17. Study of peak broadening effect in floor time histories

    International Nuclear Information System (INIS)

    Soni, R.S.; Kushwaha, H.S.; Mahajan, S.C.; Kakodkar, A.

    1996-01-01

    Seismic design of secondary systems such components and piping is usually carried out by using the floor motions at their support points. These floor motions can be in the form of Floor Response Spectra (FRS) or the Floor Time Histories (FTH). In order to account for the various uncertainties in generating these floor motions, these motions should be peak broadened and smoothened as per the regulatory codes. Presented here in this paper is the methodology to account for such peak broadening effect in the FTH. Results of this study have been compared with the FRS approach and various important conclusions have been arrived at based on the study

  18. Long-term patterns in soil acidification due to pollution in forests of the Eastern Sudetes Mountains

    International Nuclear Information System (INIS)

    Hedl, Radim; Petrik, Petr; Boublik, Karel

    2011-01-01

    Soil acidification was assessed in the Eastern Sudetes Mountains (Czech Republic) between 1941 and 2003, i.e. before and after the period of major industrial pollution (1950s-1990s). The twenty sites included in our study were distributed along a gradient of altitude ranging 1000 m. Values of pH have decreased in 80-90% of the pairs of samples after the six decades, on average by 0.7 for pH-H 2 O and 0.6 for pH-KCl. Organic matter increased in the topsoil, probably reflecting a change in decomposition conditions. The most important finding is that the acidification varies along the joint gradient of altitude/tree layer composition, and displays a changing pattern in three soil horizons (A, B and C). Contrary to expectations, most acidified were soils in beech forests at lower elevations. - Highlights: → Soil acidification varies along the joint gradient of altitude/tree composition. → Soil acidification displays a changing pattern in topsoil and subsoil horizons. → Acidification rate is stronger in soils of beech forests at lower elevation. → Historical measurements provide a reliable evidence of long-term soil acidification. - Strong acidification decreasing with altitude was observed in forest soils resurveyed after more than half a century.

  19. Hawking spectrum for a fiber-optical analog of the event horizon

    Science.gov (United States)

    Bermudez, David; Leonhardt, Ulf

    2016-05-01

    Hawking radiation has been regarded as a more general phenomenon than in gravitational physics, in particular in laboratory analogs of the event horizon. Here we consider the fiber-optical analog of the event horizon, where intense light pulses in fibers establish horizons for probe light. Then, we calculate the Hawking spectrum in an experimentally realizable system. We found that the Hawking radiation is peaked around group-velocity horizons in which the speed of the pulse matches the group velocity of the probe light. The radiation nearly vanishes at the phase horizon where the speed of the pulse matches the phase velocity of light.

  20. On Long Memory Origins and Forecast Horizons

    DEFF Research Database (Denmark)

    Vera-Valdés, J. Eduardo

    Most long memory forecasting studies assume that the memory is generated by the fractional difference operator. We argue that the most cited theoretical arguments for the presence of long memory do not imply the fractional difference operator, and assess the performance of the autoregressive...... fractionally integrated moving average (ARFIMA) model when forecasting series with long memory generated by nonfractional processes. We find that high-order autoregressive (AR) models produce similar or superior forecast performance than ARFIMA models at short horizons. Nonetheless, as the forecast horizon...... increases, the ARFIMA models tend to dominate in forecast performance. Hence, ARFIMA models are well suited for forecasts of long memory processes regardless of the long memory generating mechanism, particularly for medium and long forecast horizons. Additionally, we analyse the forecasting performance...

  1. An Improved Prediction Model for the Impact Sound Level of Lightweight Floors: Introducing Decoupled Floor-Ceiling and Beam-Plate Moment

    DEFF Research Database (Denmark)

    Mosharrof, Mohammad Sazzad; Brunskog, Jonas; Ljunggren, Fredrik

    2011-01-01

    the impact sound pressure level in a receiving room for a coupled floor structure where floor and ceiling are rigidly connected by beams. A theoretical model for predicting the impact sound level for a decoupled floor structure, which has no rigid mechanical connections between the floor and the ceiling......, is developed. An analytical method has been implemented, where a spatial Fourier transform method as well as the Poisson’s sum formula is applied to model transformed plate displacements. Radiated sound power was calculated from these displacements and normalized sound pressure levels were calculated in one...... and is found to be dependent on frequency, showing significant improvement in predicting impact sound level at high frequency region....

  2. Comparison of changes in the mobility of the pelvic floor muscle on during the abdominal drawing-in maneuver, maximal expiration, and pelvic floor muscle maximal contraction.

    Science.gov (United States)

    Jung, Halim; Jung, Sangwoo; Joo, Sunghee; Song, Changho

    2016-01-01

    [Purpose] The purpose of this study was to compare changes in the mobility of the pelvic floor muscle during the abdominal drawing-in maneuver, maximal expiration, and pelvic floor muscle maximal contraction. [Subjects] Thirty healthy adults participated in this study (15 men and 15 women). [Methods] All participants performed a bridge exercise and abdominal curl-up during the abdominal drawing-in maneuver, maximal expiration, and pelvic floor muscle maximal contraction. Pelvic floor mobility was evaluated as the distance from the bladder base using ultrasound. [Results] According to exercise method, bridge exercise and abdominal curl-ups led to significantly different pelvic floor mobility. The pelvic floor muscle was elevated during the abdominal drawing-in maneuver and descended during maximal expiration. Finally, pelvic floor muscle mobility was greater during abdominal curl-up than during the bridge exercise. [Conclusion] According to these results, the abdominal drawing-in maneuver induced pelvic floor muscle contraction, and pelvic floor muscle contraction was greater during the abdominal curl-up than during the bridge exercise.

  3. Distribution of the radionuclide 137Cs in the soils of a wet mountainous forest in Taiwan

    International Nuclear Information System (INIS)

    Chiu, C.-Y.; Lai, S.-Y.; Lin, Y.-M.; Chiang, H.-C.

    1999-01-01

    The behavior of 137 Cs was studied in the Yuanyang lake ecosystem, a wet mountainous forest in subtropical Taiwan. Soils investigated are either partially podzolic soils or nearly pure peats with a high organic matter concentration in the surface layer. Concentration of 137 Cs was highest in the organic surface layers, particularly in the Oe horizon or in the underlying A horizon. The downwards migration to the mineral horizons is limited, in spite of the high rainfall. Topography is a critical factor for the distribution of 137 Cs. It is shown that the concentration of 137 Cs is highest at the foot of the slope and lower near the summit and near the lakeshore. The variation of the concentration along the landscape has been attributed to erosion-deposition in combination with surface run-off of the undisturbed forest. The amount of 137 Cs in the site studied is significantly higher than at any other place in Taiwan. The accumulation of 137 Cs is attributed to the high rainfall, which brought large amounts of 137 Cs with the precipitation in the early 1960s. A very remarkable feature of the ecosystem is that 137 Cs is not leached to the subsoils, but is stored in the biomass. Due to permanent recycling it remains available, without being leached downward

  4. Deepwater Horizon - Baseline Dataset

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — In 2010, the Deepwater Horizon oil spill occurred in the Gulf of Mexico and the Natural Resources Damage Assessment (NRDA) was initiated to determine the extent of...

  5. FLOOR IDENTIFICATION WITH COMMERCIAL SMARTPHONES IN WIFI-BASED INDOOR LOCALIZATION SYSTEM

    Directory of Open Access Journals (Sweden)

    H. J. Ai

    2016-06-01

    Full Text Available In this paper, we utilize novel sensors built-in commercial smart devices to propose a schema which can identify floors with high accuracy and efficiency. This schema can be divided into two modules: floor identifying and floor change detection. Floor identifying module starts at initial phase of positioning, and responsible for determining which floor the positioning start. We have estimated two methods to identify initial floor based on K-Nearest Neighbors (KNN and BP Neural Network, respectively. In order to improve performance of KNN algorithm, we proposed a novel method based on weighting signal strength, which can identify floors robust and quickly. Floor change detection module turns on after entering into continues positioning procedure. In this module, sensors (such as accelerometer and barometer of smart devices are used to determine whether the user is going up and down stairs or taking an elevator. This method has fused different kinds of sensor data and can adapt various motion pattern of users. We conduct our experiment with mobile client on Android Phone (Nexus 5 at a four-floors building with an open area between the second and third floor. The results demonstrate that our scheme can achieve an accuracy of 99% to identify floor and 97% to detecting floor changes as a whole.

  6. Agrogenic degradation of soils in Krasnoyarsk forest-steppe

    Science.gov (United States)

    Shpedt, A. A.; Trubnikov, Yu. N.; Zharinova, N. Yu.

    2017-10-01

    Agrogenic degradation of soils in Krasnoyarsk forest-steppe was investigated. Paleocryogenic microtopography of microlows and microhighs in this area predetermined the formation of paragenetic soil series and variegated soil cover. Specific paleogeographic conditions, thin humus horizons and soil profiles, and long-term agricultural use of the land resulted in the formation of soils unstable to degradation processes and subjected to active wind and water erosion. Intensive mechanical soil disturbances during tillage and long-term incorporation of the underlying Late Pleistocene (Sartan) calcareous silty and clay loams into the upper soil horizons during tillage adversely affected the soil properties. We determined the contents of total and labile humus and easily decomposable organic matter and evaluated the degree of soil exhaustion. It was concluded that in the case of ignorance of the norms of land use and soil conservation practices, intense soil degradation would continue leading to complete destruction of the soil cover within large areas.

  7. The influence of flooring on environmental stressors: a study of three flooring materials in a hospital.

    Science.gov (United States)

    Harris, Debra D

    2015-01-01

    Three flooring materials, terrazzo, rubber, and carpet tile, in patient unit corridors were compared for absorption of sound, comfort, light reflectance, employee perceptions and preferences, and patient satisfaction. Environmental stressors, such as noise and ergonomic factors, effect healthcare workers and patients, contributing to increased fatigue, anxiety and stress, decreased productivity, and patient safety and satisfaction. A longitudinal comparative cohort study comparing three types of flooring assessed sound levels, healthcare worker responses, and patient Hospital Consumer Assessment of Healthcare Providers and Systems (HCAHPS) ratings over 42 weeks. A linear mixed model analysis was conducted to determine significant differences between the means for participant responses and objective sound meter data during all three phases of the study. A significant difference was found for sound levels between flooring type for equivalent continuous sound levels. Carpet tile performed better for sound attenuation by absorption, reducing sound levels 3.14 dBA. Preferences for flooring materials changed over the course of the study. The HCAHPS ratings aligned with the sound meter data showing that patients perceived the noise levels to be lower with carpet tiles, improving patient satisfaction ratings. Perceptions for healthcare staff and patients were aligned with the sound meter data. Carpet tile provides sound absorption that affects sound levels and influences occupant's perceptions of environmental factors that contribute to the quality of the indoor environment. Flooring that provides comfort underfoot, easy cleanability, and sound absorption influence healthcare worker job satisfaction and patient satisfaction with their patient experience. © The Author(s) 2015.

  8. Recognition and Management of Nonrelaxing Pelvic Floor Dysfunction

    Science.gov (United States)

    Faubion, Stephanie S.; Shuster, Lynne T.; Bharucha, Adil E.

    2012-01-01

    Nonrelaxing pelvic floor dysfunction is not widely recognized. Unlike in pelvic floor disorders caused by relaxed muscles (eg, pelvic organ prolapse or urinary incontinence, both of which often are identified readily), women affected by nonrelaxing pelvic floor dysfunction may present with a broad range of nonspecific symptoms. These may include pain and problems with defecation, urination, and sexual function, which require relaxation and coordination of pelvic floor muscles and urinary and anal sphincters. These symptoms may adversely affect quality of life. Focus on the global symptom complex, rather than the individual symptoms, may help the clinician identify the condition. The primary care provider is in a position to intervene early, efficiently, and effectively by (1) recognizing the range of symptoms that might suggest nonrelaxing pelvic floor dysfunction, (2) educating patients, (3) performing selective tests when needed to confirm the diagnosis, and (4) providing early referral for physical therapy. PMID:22305030

  9. Glazed Tiles as Floor Finish in Nigeria

    Directory of Open Access Journals (Sweden)

    Toyin Emmanuel AKINDE

    2013-09-01

    Full Text Available Tile is no doubt rich in antiquity; its primordial  show, came as mosaic with primary prospect in sacred floor finish before its oblivion, courtesy of, later consciousness towards wall finish in banquets, kitchens, toilets, restaurants and even bars. Today, its renaissance as floor finish is apparent in private and public architectural structures with prevalence in residential, recreational, commercial, governmental and other spaces. In Nigeria, the use of glazed tiles as floor finish became apparent, supposedly in mid-twentieth century; and has since, witnessed ever increasing demands from all sundry; a development that is nascent and has necessitated its mass  production locally with pockets of firms in the country. The latter however, is a resultant response to taste cum glazed tiles affordability, whose divergent sophistication in design, colour, size and shape is believed preferred to terrazzo, carpet and floor flex tile. Accessible as glazed tile and production is, in recent times; its dearth of a holistic literature in Nigeria is obvious. In the light of the latter, this paper examine glazed tiles as floor finish in Nigeria, its advent, usage, production, challenge, benefit and prospect with the hope of opening further frontier in discipline specifics.

  10. WOODEN FLOORING – BETWEEN PRESENT AND FUTURE

    Directory of Open Access Journals (Sweden)

    Ivan CISMARU

    2015-06-01

    Full Text Available The paper aims at presenting a systematization of the wood floors, both in terms of the areas of application, and in terms of the fastening solutions and structures in constructions. In this respect, an extensive bibliographic research was achieved, on the researchers’ preoccupations. Starting from the current situation and forecasting the future, from the point of view of the chances held by wooden flooring, in competition with other types of materials, we dare say the wooden flooring or the wood in combination with other materials are not likely to be eliminated from the “civil-engineering market”. The wood floors are likely to develop as an application, especially in the area of the “special floors”, specific to the indoor sports or social halls; and even for some industrial sectors, with strict operating conditions (elasticity, thermal insulation, soundproofing that cannot be provided by other types of materials or structures. Starting from this last observation, the paper also aims at submitting current opinions with respect to this type of floors, both in the light of the current databases and in the light of the future researches, to this end

  11. Nitrogen distribution and cycling through water flows in a subtropical bamboo forest under high level of atmospheric deposition.

    Directory of Open Access Journals (Sweden)

    Li-hua Tu

    Full Text Available BACKGROUND: The hydrological cycle is an important way of transportation and reallocation of reactive nitrogen (N in forest ecosystems. However, under a high level of atmospheric N deposition, the N distribution and cycling through water flows in forest ecosystems especially in bamboo ecosystems are not well understood. METHODOLOGY/PRINCIPAL FINDINGS: In order to investigate N fluxes through water flows in a Pleioblastus amarus bamboo forest, event rainfall/snowfall (precipitation, PP, throughfall (TF, stemflow (SF, surface runoff (SR, forest floor leachate (FFL, soil water at the depth of 40 cm (SW1 and 100 cm (SW2 were collected and measured through the whole year of 2009. Nitrogen distribution in different pools in this ecosystem was also measured. Mean N pools in vegetation and soil (0-1 m were 351.7 and 7752.8 kg ha(-1. Open field nitrogen deposition at the study site was 113.8 kg N ha(-1 yr(-1, which was one of the highest in the world. N-NH4(+, N-NO3(- and dissolved organic N (DON accounted for 54%, 22% and 24% of total wet N deposition. Net canopy accumulated of N occurred with N-NO3(- and DON but not N-NH4(+. The flux of total dissolved N (TDN to the forest floor was greater than that in open field precipitation by 17.7 kg N ha(-1 yr(-1, due to capture of dry and cloudwater deposition net of canopy uptake. There were significant negative exponential relationships between monthly water flow depths and monthly mean TDN concentrations in PP, TF, SR, FFL and SW1. CONCLUSIONS/SIGNIFICANCE: The open field nitrogen deposition through precipitation is very high over the world, which is the main way of reactive N input in this bamboo ecosystem. The water exchange and N consume mainly occurred in the litter floor layer and topsoil layer, where most of fine roots of bamboo distributed.

  12. Carbon and Nitrogen dynamics in forest soils depending on light conditions and tree species

    Science.gov (United States)

    Veselinovic, Bojana; Hager, Herbert

    2013-04-01

    Climate change mitigation actions under the Kyoto Protocol apply among other decreases of CO2-emissions and/or increases of carbon (C) stocks. As soils represent the second biggest C-reservoir on Earth, an exact estimation of the stocks and reliable knowledge on C-dynamics in forest soils is of high importance. Anyhow, here, the accurate GHG-accounting, emission reductions and increase in C stocks is hampered due to lack of reliable data and solid statistical methods for the factors which influence C-sequestration in and its release from these systems. In spite of good progress in the scientific research, these factors are numerous and diverse in their interactions. This work focuses on influence of the economically relevant tree species - Picea abies, Fagus sylvatica and Quercus spp. - and light conditions on forest floor and mineral soil C and N dynamics in forest soils. Spruce monocultures have been widely used management practices in central European forests during the past century. Such stands are in lower altitudes and on heavy and water logged soils unstable and prone to disturbances, especially to windthrows. We hypothesize that windthrow areas loose C & N and that the establishment of the previous nutrient stocks is, if at all, only possible to be reached over the longer periods of time. We research also how the increased OM depletion affects the change of C & N stocks in forest floor vs. mineral soil. Conversion of such secondary spruce monocultures to site adequate beech and oak forests may enable higher stocks allocated predominantly as stable organic carbon and as plant available nitrogen. For this purpose sites at 300-700 m altitude with planosols were chosen in the region of the Northern Alpine Foothills. A false chronosequence approach was used in order to evaluate the impacts of the tree species and change in light conditions on dynamic of C & N in the forest floor and mineral soil, over the period 0-100 (for oak 120 y.) years. The C- and N

  13. What Is Low Profile Access Flooring and Why More Businesses Need It

    OpenAIRE

    NetfloorUSA

    2017-01-01

    Low profile access flooring is being commonly used in a variety of businesses today. To understand why more businesses, need this type of flooring, it is essential that we take the time to first understand what is low profile flooring actually is. What Is Low Profile Access Flooring A low profile access floor is a floor that is designed to sit above the original concrete slab flooring installed in any home, business, or public building. The higher floor height creates a space between ...

  14. Polygons on Crater Floor

    Science.gov (United States)

    2003-01-01

    MGS MOC Release No. MOC2-357, 11 May 2003This Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) picture shows a pattern of polygons on the floor of a northern plains impact crater. These landforms are common on crater floors at high latitudes on Mars. Similar polygons occur in the arctic and antarctic regions of Earth, where they indicate the presence and freeze-thaw cycling of ground ice. Whether the polygons on Mars also indicate water ice in the ground is uncertain. The image is located in a crater at 64.8oN, 292.7oW. Sunlight illuminates the scene from the lower left.

  15. Field surveying of radionuclide contamination in forests

    International Nuclear Information System (INIS)

    Turunen, J.; Rantavaara, A.; Ammann, M.

    2009-01-01

    Field measurements of radionuclides after an accidental contamination of forests assume the capacity for identification of a number of nuclides in varying source geometries. The continuous redistribution of radionuclides in forests through natural processes implies a decrease of prevailing surface contamination of trees and an increase in activity density on the ground. Portable gamma spectrometers have long been based on Na(I) detectors which, due to their low energy resolution, are not the tool for analysis of contamination from accidental releases of fission and activation products in the first days or weeks after a deposition. Data of airborne radionuclides from the Chernobyl accident in April 1986 were used for demonstration of initial and later distribution of radionuclides as sources of air Kerma in forests. Forest model (FDMF, PV. 6.0) of the RODOS system was used for the assessment of time-dependent Kerma rate from different forest compartments. The results show the fast reduction of activities of short-lived nuclides and their contributions to the Kerma rate in the first weeks and months. The results also give an estimate for the time needed until a gamma spectrometer with a low energy resolution would give useful information about long-lived radioactivity on the forest floor. An example is given on a portable high resolution semiconductor spectrometer that has suitable characteristics for field surveying also during occurrence of a great number of radionuclides contributing to the gamma spectrum. The needs for further research of a recently deposited radionuclide contamination on forest vegetation and soil, and the efforts for improvement of portable radiation meters and their use in management planning and radioecological research on contaminated forests are discussed. (au)

  16. The two event horizons - an apparent contribution of vacuum to gravitation

    International Nuclear Information System (INIS)

    Dinculescu, A.

    1994-01-01

    Our possibilities of investigation are limited by two horizons: a local one - the black hole horizon R 0 , and the global one - the cosmic horizon R u . Till now, only the first horizon has been taken into consideration as a measure of the curvature of space near a massive body. It is argued that in order to satisfy Mach's principle when characterizing matter in a point relative to a center of mass, one has to take into consideration both event horizons. Accordingly, a local cosmological term Λ * =(R 0 R u ) -1 is defined as a combination of the above horizons in a given point. The corresponding non-dimensional coefficient ξ=Λ * R 2 is an indicator of the position of a mass point between the two event horizons. When taking into account as a contribution of vacuum energy to the gravitational field it restores the low of conservation of energy in an expanding universe, and explains the dynamics of galaxies and clusters of galaxies without resorting to the 'dark matter' hypothesis. (Author) 3 Tabs., 38 Refs

  17. Proposed cuts to Horizon 2020 are short-sighted

    CERN Multimedia

    2015-01-01

    When the latest incarnation of Europe’s framework programme for science funding, Horizon 2020, was announced, it was to great acclaim. Horizon 2020 builds on the already considerable success of its forerunners, which have made international research at the European level a reality and have contributed greatly to European competitiveness on the world stage.   We at CERN have benefited considerably, through projects that have enabled us to build on CERN’s core competencies to develop science at the grass-roots level across the continent. Horizon 2020 is more ambitious and more streamlined than its predecessors, and, funded at the level of €70 billion over seven years, it is potentially transformative. All of which makes the Commission’s plan to raid the Horizon 2020 budget to the tune of €2.7 billion rather incomprehensible. Keen to stimulate Europe’s economies, Commission President Jean-Claude Juncker has proposed a €21 billio...

  18. 17 CFR 240.11a-1 - Regulation of floor trading.

    Science.gov (United States)

    2010-04-01

    ... 17 Commodity and Securities Exchanges 3 2010-04-01 2010-04-01 false Regulation of floor trading... Securities Exchange Act of 1934 Adoption of Floor Trading Regulation (rule 11a-1) § 240.11a-1 Regulation of floor trading. (a) No member of a national securities exchange, while on the floor of such exchange...

  19. VMware Horizon View 6 desktop virtualization cookbook

    CERN Document Server

    Ventresco, Jason

    2014-01-01

    If you want a more detailed explanation concerning the implementation of several different core features of VMware Horizon View, this is the book for you. Whether you are new to VMware Horizon View or an existing user, this book will provide you with the knowledge you need to successfully deploy several core features and get introduced to the latest features of version 6.0 as well.

  20. Physical distribution of oak strip flooring 1969

    Science.gov (United States)

    William C. Miller; William C. Miller

    1971-01-01

    As an aid to the marketing of oak strip flooring, a study was made of the distribution process for this product, from manufacture to consumer-where the flooring came from, where it went, how much was shipped, and who handled it.

  1. Transient cultivation and fallow land in forests. Measurements of the specific activity of the carbon in organic matter fractions for the purpose of studying the renewal of the store of organic matter in an equatorial forest environment

    International Nuclear Information System (INIS)

    Turenne, J.F.; Rapaire, J.L.

    1979-01-01

    Different conditions of forest-type fallow land and of clearings in the equatorial forests of the Amazon region provide a basis for determining the nature, the direction and the magnitude of the transformations of the organic matter of the soil when cultivated, using the variations in the specific activity of atmospheric carbon. Calculations of the renewal rates of surface horizon organic matter show that there are two groups of products, (a) humin, a labile fraction with a high renewal rate, and (b) humic and fulvic products with a lower renewal rate. The effect of clearing is generally to retard these renewal rates. The dynamics which become established in forest fallow land mainly involve the fulvic products, and the return to forest equilibrium can be considered to occur between 60 and 100 years after clearing. (author)

  2. Pelvic floor muscle training as a persistent nursing intervention: Effect on delivery outcome and pelvic floor myodynamia

    Directory of Open Access Journals (Sweden)

    Xin Wang

    2014-03-01

    Conclusion: Persistent nursing intervention for pregnant/postpartum women helped to shorten the second stage of labour and contributed to the recovery of postpartum pelvic floor myodynamia. The influence of this intervention on the delivery mode, and rates of episiotomy and perineal laceration remains unknown. Medical staff should strengthen health education programmes that involve pelvic floor functional rehabilitation.

  3. Planning horizon affects prophylactic decision-making and epidemic dynamics.

    Science.gov (United States)

    Nardin, Luis G; Miller, Craig R; Ridenhour, Benjamin J; Krone, Stephen M; Joyce, Paul; Baumgaertner, Bert O

    2016-01-01

    The spread of infectious diseases can be impacted by human behavior, and behavioral decisions often depend implicitly on a planning horizon-the time in the future over which options are weighed. We investigate the effects of planning horizons on epidemic dynamics. We developed an epidemiological agent-based model (along with an ODE analog) to explore the decision-making of self-interested individuals on adopting prophylactic behavior. The decision-making process incorporates prophylaxis efficacy and disease prevalence with the individuals' payoffs and planning horizon. Our results show that for short and long planning horizons individuals do not consider engaging in prophylactic behavior. In contrast, individuals adopt prophylactic behavior when considering intermediate planning horizons. Such adoption, however, is not always monotonically associated with the prevalence of the disease, depending on the perceived protection efficacy and the disease parameters. Adoption of prophylactic behavior reduces the epidemic peak size while prolonging the epidemic and potentially generates secondary waves of infection. These effects can be made stronger by increasing the behavioral decision frequency or distorting an individual's perceived risk of infection.

  4. Entropy bound of horizons for accelerating, rotating and charged Plebanski–Demianski black hole

    International Nuclear Information System (INIS)

    Debnath, Ujjal

    2016-01-01

    We first review the accelerating, rotating and charged Plebanski–Demianski (PD) black hole, which includes the Kerr–Newman rotating black hole and the Taub-NUT spacetime. The main feature of this black hole is that it has 4 horizons like event horizon, Cauchy horizon and two accelerating horizons. In the non-extremal case, the surface area, entropy, surface gravity, temperature, angular velocity, Komar energy and irreducible mass on the event horizon and Cauchy horizon are presented for PD black hole. The entropy product, temperature product, Komar energy product and irreducible mass product have been found for event horizon and Cauchy horizon. Also their sums are found for both horizons. All these relations are dependent on the mass of the PD black hole and other parameters. So all the products are not universal for PD black hole. The entropy and area bounds for two horizons have been investigated. Also we found the Christodoulou–Ruffini mass for extremal PD black hole. Finally, using first law of thermodynamics, we also found the Smarr relation for PD black hole.

  5. Entropy bound of horizons for accelerating, rotating and charged Plebanski–Demianski black hole

    Energy Technology Data Exchange (ETDEWEB)

    Debnath, Ujjal, E-mail: ujjaldebnath@yahoo.com

    2016-09-15

    We first review the accelerating, rotating and charged Plebanski–Demianski (PD) black hole, which includes the Kerr–Newman rotating black hole and the Taub-NUT spacetime. The main feature of this black hole is that it has 4 horizons like event horizon, Cauchy horizon and two accelerating horizons. In the non-extremal case, the surface area, entropy, surface gravity, temperature, angular velocity, Komar energy and irreducible mass on the event horizon and Cauchy horizon are presented for PD black hole. The entropy product, temperature product, Komar energy product and irreducible mass product have been found for event horizon and Cauchy horizon. Also their sums are found for both horizons. All these relations are dependent on the mass of the PD black hole and other parameters. So all the products are not universal for PD black hole. The entropy and area bounds for two horizons have been investigated. Also we found the Christodoulou–Ruffini mass for extremal PD black hole. Finally, using first law of thermodynamics, we also found the Smarr relation for PD black hole.

  6. Assessment of the effect of pelvic floor exercises on pelvic floor muscle strength using ultrasonography in patients with urinary incontinence: a prospective randomized controlled trial

    OpenAIRE

    Tosun, Ozge Celiker; Solmaz, Ulas; Ekin, Atalay; Tosun, Gokhan; Gezer, Cenk; Ergenoglu, Ahmet Mete; Yeniel, Ahmet Ozgur; Mat, Emre; Malkoc, Mehtap; Askar, Niyazi

    2016-01-01

    [Purpose] The aim of this study was to evaluate whether the effect of pelvic floor exercises on pelvic floor muscle strength could be detected via ultrasonography in patients with urinary incontinence. [Subjects and Methods] Of 282 incontinent patients, 116 participated in the study and were randomly divided into a pelvic floor muscle training (n=65) group or control group (n=51). The pelvic floor muscle training group was given pelvic floor exercise training for 12 weeks. Both groups were ev...

  7. Air gun near the sea floor as shear-wave source?

    NARCIS (Netherlands)

    Drijkoningen, G.G.; Dieulangard, D.; Holicki, M.E.

    2015-01-01

    The feasibility of using an air gun near the sea floor as shear-wave source has been investigated. With an air gun near the sea floor, an evanescent P-wave in the water becomes a propagating S-wave in the sea floor, such that it seems that a pure shear-wave source has been used at the sea floor.

  8. Conference Offers Girls Opportunity to Expand Career Horizons

    Science.gov (United States)

    Offers Girls Opportunity to Expand Career Horizons For more information contact: e:mail: Public Affairs Golden, Colo., Feb. 11, 1997 -- Expanding Your Horizons, a conference for girls grades 6 - 9 and Employed Women, Girls Incorporated of Metro Denver, King Soopers, McDonalds, the TCI Adult Program and the

  9. Dermoid cyst in the mouth floor

    International Nuclear Information System (INIS)

    Portelles Masso, Ayelen Maria; Torres Inniguez, Ailin Tamara.

    2010-01-01

    The Dermoid cyst account for the 0.01 % of all cysts of buccal cavity. Its more frequent location is in the mouth floor. This is the case of a female patient aged 19 who approximately 7 years noted an increase of volume under tongue growing gradually and noting outside face and the discomfort at to speak and to chew. Complementary studies were conducted and under general anesthesia a surgical exeresis was carried out by intrabuccal approach achieving excellent esthetic and functional results. Histopathologic diagnosis matched with a dermoid cyst of mouth floor. Patient has not lesion recurrence after three years after operation. We conclude that the Dermoid cyst of mouth floor appear as benign tumor of middle line. The intrabuccal exeresis demonstrates esthetic and functional benefits. (author)

  10. Event and Apparent Horizon Finders for 3 + 1 Numerical Relativity.

    Science.gov (United States)

    Thornburg, Jonathan

    2007-01-01

    Event and apparent horizons are key diagnostics for the presence and properties of black holes. In this article I review numerical algorithms and codes for finding event and apparent horizons in numerically-computed spacetimes, focusing on calculations done using the 3 + 1 ADM formalism. The event horizon of an asymptotically-flat spacetime is the boundary between those events from which a future-pointing null geodesic can reach future null infinity and those events from which no such geodesic exists. The event horizon is a (continuous) null surface in spacetime. The event horizon is defined nonlocally in time : it is a global property of the entire spacetime and must be found in a separate post-processing phase after all (or at least the nonstationary part) of spacetime has been numerically computed. There are three basic algorithms for finding event horizons, based on integrating null geodesics forwards in time, integrating null geodesics backwards in time, and integrating null surfaces backwards in time. The last of these is generally the most efficient and accurate. In contrast to an event horizon, an apparent horizon is defined locally in time in a spacelike slice and depends only on data in that slice, so it can be (and usually is) found during the numerical computation of a spacetime. A marginally outer trapped surface (MOTS) in a slice is a smooth closed 2-surface whose future-pointing outgoing null geodesics have zero expansion Θ. An apparent horizon is then defined as a MOTS not contained in any other MOTS. The MOTS condition is a nonlinear elliptic partial differential equation (PDE) for the surface shape, containing the ADM 3-metric, its spatial derivatives, and the extrinsic curvature as coefficients. Most "apparent horizon" finders actually find MOTSs. There are a large number of apparent horizon finding algorithms, with differing trade-offs between speed, robustness, accuracy, and ease of programming. In axisymmetry, shooting algorithms work well

  11. Gravitational pressure, apparent horizon and thermodynamics of FLRW universe in the teleparallel gravity

    Science.gov (United States)

    da Rocha-Neto, J. F.; Morais, B. R.

    2018-04-01

    In the context of the teleparallel equivalent of general relativity the concept of gravitational pressure and gravitational energy-momentum arisen in a natural way. In the case of a Friedmann-Lemaitre-Robertson-Walker space FLRW we obtain the total energy contained inside the apparent horizon and the radial pressure over the apparent horizon area. We use these definitions to written a thermodynamics relation TAdSA = dEA+PAdVA at the apparent horizon, where EA is the total energy inside the apparent horizon, VA is the areal volume of the apparent horizon, PA is the radial pressure over the apparent horizon area, SA is the entropy which can be assumed as one quarter of the apparent horizon area only for a non stationary apparent horizon. We identify TA as the temperature at the surface of the apparent horizon. We shown that for all expanding accelerated FLRW model of universe the radial pressure is positive.

  12. Improving the cleaning procedure to make kitchen floors less slippery.

    Science.gov (United States)

    Quirion, F; Poirier, P; Lehane, P

    2008-12-01

    This investigation shows that, in most cases, the floor cleaning procedure of typical restaurants could be improved, resulting in a better cleaning efficiency and a better floor friction. This simple approach could help reduce slips and falls in the workplace. Food safety officers visited ten European style restaurants in the London Borough of Bromley (UK) to identify their floor cleaning procedure in terms of the cleaning method, the concentration and type of floor cleaner and the temperature of the wash water. For all 10 restaurants visited, the cleaning method was damp mopping. Degreasers were used in three sites while neutral floor cleaners were used in seven sites. Typically, the degreasers were over diluted and the neutrals were overdosed. The wash water temperature ranged from 10 to 72 degrees C. The on-site cleaning procedures were repeated in the laboratory for the removal of olive oil from new and sealed quarry tiles, fouled and worn quarry tiles and new porcelain tiles. It is found that in 24 out of 30 cases, cleaning efficiency can be improved by simple changes in the floor cleaning procedure and that these changes result in a significant improvement of the floor friction. The nature of the improved floor cleaning procedure depends on the flooring type. New and properly sealed flooring tiles can be cleaned using damp mopping with a degreaser diluted as recommended by the manufacturer in warm or hot water (24 to 50 degrees C). But as the tiles become worn and fouled, a more aggressive floor cleaning is required such as two-step mopping with a degreaser diluted as recommended by the manufacturer in warm water (24 degrees C).

  13. Nondestructive structural evaluation of wood floor systems with a vibration technique.

    Science.gov (United States)

    Xiping Wang; Robert J. Ross; Lawrence Andrew Soltis

    2002-01-01

    The objective of this study was to determine if transverse vibration methods could be used to effectively assess the structural integrity of wood floors as component systems. A total of 10 wood floor systems, including 3 laboratory-built floor sections and 7 in-place floors in historic buildings, were tested. A forced vibration method was applied to the floor systems...

  14. Improvement of PVC floor tiles by gamma radiation

    International Nuclear Information System (INIS)

    Plessis, T.A. du; Badenhorst, F.

    1988-01-01

    Gamma radiation presents a unique method of transforming highly plasticized PVC floor tiles, manufactured at high speed through injection moulding, into a high quality floor covering at a cost at least 30% less than similarly rated rubber tiles. A specially formulated PVC compound was developed in collaboration with a leading manufacturer of floor tiles. These tiles are gamma crosslinked in its shipping cartons to form a dimensionally stable product which is highly fire resistant and inert to most chemicals and solvents. These crosslinked tiles are more flexible than the highly filled conventional PVC floor tiles, scratch resistant and have a longer lifespan and increased colour fastness. These tiles are also less expensive to install than conventional rubber tiles. (author)

  15. Geometric properties of static Einstein-Maxwell dilaton horizons with a Liouville potential

    International Nuclear Information System (INIS)

    Abdolrahimi, Shohreh; Shoom, Andrey A.

    2011-01-01

    We study nondegenerate and degenerate (extremal) Killing horizons of arbitrary geometry and topology within the Einstein-Maxwell-dilaton model with a Liouville potential (the EMdL model) in d-dimensional (d≥4) static space-times. Using Israel's description of a static space-time, we construct the EMdL equations and the space-time curvature invariants: the Ricci scalar, the square of the Ricci tensor, and the Kretschmann scalar. Assuming that space-time metric functions and the model fields are real analytic functions in the vicinity of a space-time horizon, we study the behavior of the space-time metric and the fields near the horizon and derive relations between the space-time curvature invariants calculated on the horizon and geometric invariants of the horizon surface. The derived relations generalize similar relations known for horizons of static four- and five-dimensional vacuum and four-dimensional electrovacuum space-times. Our analysis shows that all the extremal horizon surfaces are Einstein spaces. We present the necessary conditions for the existence of static extremal horizons within the EMdL model.

  16. The Event Horizon of The Schwarzschild Black Hole in Noncommutative Spaces

    OpenAIRE

    Nasseri, Forough

    2005-01-01

    The event horizon of Schwarzschild black hole is obtained in noncommutative spaces up to the second order of perturbative calculations. Because this type of black hole is non-rotating, to the first order there is no any effect on the event horizon due to the noncommutativity of space. A lower limit for the noncommutativity parameter is also obtained. As a result, the event horizon in noncommutative spaces is less than the event horizon in commutative spaces.

  17. On crossing the Cauchy horizon of a Reissner-Nordstroem black-hole

    International Nuclear Information System (INIS)

    Chandrasekhar, S.; Hartle, J.B.

    1982-01-01

    The behaviour, on the Cauchy horizon, of a flux of gravitational and/or electromagnetic radiation crossing the event horizon of a Reissner-Nordstroem black-hole is investigated as a problem in the theory of one-dimensional potential-scattering. It is shown that the flux of radiation received by an observer crossing the Cauchy horizon, along a radial time-like geodesic, diverges for all physically perturbations crossing the event horizon, even including those with compact support. (author)

  18. The pelvic floor muscles: muscle thickness in healthy and urinary-incontinent women measured by perineal ultrasonography with reference to the effect of pelvic floor training. Estrogen receptor studies

    DEFF Research Database (Denmark)

    Bernstein, Inge Thomsen

    1997-01-01

    demonstrated that the striated periurethral muscles and the pelvic floor muscles are of paramount importance for the closure function. This emphasizes the importance of well-functioning pelvic floor muscles to obtain continence, and probably explains the rationale for the effect of pelvic floor training...... in treating urinary incontinence. This study presents a review of the literature on female urinary incontinence, continence mechanisms, pelvic floor muscles, and pelvic floor training. Furthermore, a review of the literature on estrogen receptors in the pelvic floor muscles is given. Perineal ultrasonography...... the effect of pelvic floor training. Additionally, a study of the Pelvic floor muscles was performed to assess the presence of estrogen receptors. Muscle thickness seems to decrease with age. In women over age 60 years, a significantly thinner pelvic floor muscle was found compared to younger women...

  19. Piezoelectric energy harvester under parquet floor

    Science.gov (United States)

    Bischur, E.; Schwesinger, N.

    2011-03-01

    The design, fabrication and testing of piezoelectric energy harvesting modules for floors is described. These modules are used beneath a parquet floor to harvest the energy of people walking over it. The harvesting modules consist of monoaxial stretched PVDF-foils. Multilayer modules are built up as roller-type capacitors. The fabrication process of the harvesting modules is simple and very suitable for mass production. Due to the use of organic polymers, the modules are characterized by a great flexibility and the possibility to create them in almost any geometrical size. The energy yield was determined depending on the dynamic loading force, the thickness of piezoelectric active material, the size of the piezoelectric modules, their alignment in the walking direction and their position on the floor. An increase of the energy yield at higher loading forces and higher thicknesses of the modules was observed. It was possible to generate up to 2.1mWs of electric energy with dynamic loads of 70kg using a specific module design. Furthermore a test floor was assembled to determine the influence of the size, alignment and position of the modules on the energy yield.

  20. 75 FR 70061 - Dealer Floor Plan Pilot Program Meeting

    Science.gov (United States)

    2010-11-16

    ... SMALL BUSINESS ADMINISTRATION Dealer Floor Plan Pilot Program Meeting AGENCY: U.S. Small Business... location, date, time, and agenda for a meeting regarding the Dealer Floor Plan Pilot Program established in the Small Business Jobs Act of 2010. The meeting will be open to the public. DATES: The Dealer Floor...