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Sample records for winter temperate zone

  1. Long range transport of caesium isotopes from temperate latitudes to the equatorial zone during the winter monsoon period

    International Nuclear Information System (INIS)

    An air radioactivity monitoring study carried out at Dalat, Viet Nam, since 1986 has revealed distinct peaks of caesium isotope concentrations in air and fallout during the period of December and January when the monthly average air temperature was lowest and dry fallout dominated. These peaks provide evidence of the intrusion of more radioactive cold air masses from temperate northern latitudes during the development of large scale anticyclones, frequently observed in the most active winter monsoon period. The high dry fallout velocity (about 10 cm/s), determined from the measured concentrations, clearly demonstrates one of the most relevant features of cold air masses: behind the cold front, vertical air motion is descending. The role of other processes such as injection of radioactive air from the stratosphere and local resuspension of soil dust has been shown to be insignificant. The interpretation of the experimental results was based on the analysis of environmental-meteorological factors as well as the behaviour of other naturally occurring radionuclides. (author). 7 refs, 2 figs

  2. Winter disturbances and riverine fish in temperate and cold regions

    OpenAIRE

    Weber, Christine; Nilsson, Christer; Lind, Lovisa; Alfredsen, Knut T.; Polvi, Lina E.

    2013-01-01

    Winter is a critical period for aquatic organisms; however, little is known about the ecological significance of its extreme events. Here, we link winter ecology and disturbance research by synthesizing the impacts of extreme winter conditions on riverine habitats and fish assemblages in temperate and cold regions. We characterize winter disturbances by their temporal pattern and abiotic effects, explore how various drivers influence fish, and discuss human alterations of winter disturbances ...

  3. Recurrent winter warming pulses enhance nitrogen cycling and soil biotic activity in temperate heathland and grassland mesocosms

    Directory of Open Access Journals (Sweden)

    J. Schuerings

    2014-06-01

    Full Text Available Winter air temperatures are projected to increase in the temperate zone, whereas snow cover is projected to decrease, leading to more extreme soil temperature variability, and potentially to changes in nutrient cycling. Therefore, we applied six winter warming pulses by infra-red heating lamps and surface heating wires in a field experiment over one winter in temperate heathland and grassland mesocosms. The experiment was replicated at two sites, a colder mountainous upland site with high snow accumulation and a warmer and dryer lowland site. Winter warming pulses enhanced soil biotic activity for both sites during winter, as indicated by 35% higher nitrogen (N availability in the soil solution, 40% higher belowground decomposition and a 25% increase in the activity of the enzyme cellobiohydrolase. The mobilization of N differed between sites, and the incorporation of 15N into leaves was reduced by 31% in response to winter warming pulses, but only at the cold site, with significant reductions occurring for three of four tested plant species at this site. Furthermore, there was a trend of increased N leaching in response to the recurrent winter warming pulses. Overall, projected winter climate change in the temperate zone, with less snow and more variable soil temperatures, appears important for shifts in ecosystem functioning (i.e. nutrient cycling. While the effects of warming pulses on plant N mobilization did not differ among sites, reduced plant 15N incorporation at the colder temperate site suggests that frost damage may reduce plant performance in a warmer world, with important implications for nitrogen cycling and nitrogen losses from ecosystems.

  4. Plasmodium vivax malaria : a re-emerging threat for temperate climate zones?

    DEFF Research Database (Denmark)

    Petersen, Eskild; Severini, Carlo

    2013-01-01

    Plasmodium vivax was endemic in temperate areas in historic times up to the middle of last century. Temperate climate P. vivax has a long incubation time of up to 8-10 months, which partly explain how it can be endemic in temperate areas with a could winter. P. vivax disappeared from Europe within the last 40-60 years, and this change was not related to climatic changes. The surge of P. vivax in Northern Europe after the second world war was related to displacement of refugees and large movement of military personnel exposed to malaria. Lately P. vivax has been seen along the demilitarized zone in South Korea replication a high endemicity in North Korea. The potential of transmission of P. vivax still exist in temperate zones, but reintroduction in a larger scale of P. vivax to areas without present transmission require large population movements of P. vivax infected people. The highest threat at present is refugees from P. vivax endemic North Korea entering China and South Korea in large numbers.

  5. Increased winter soil temperature variability enhances nitrogen cycling and soil biotic activity in temperate heathland and grassland mesocosms

    Science.gov (United States)

    Schuerings, J.; Jentsch, A.; Hammerl, V.; Lenz, K.; Henry, H. A. L.; Malyshev, A. V.; Kreyling, J.

    2014-12-01

    Winter air temperatures are projected to increase in the temperate zone, whereas snow cover is projected to decrease, leading to increased soil temperature variability, and potentially to changes in nutrient cycling. Here, we experimentally evaluated the effects of increased winter soil temperature variability on selected aspects of the N-cycle in mesocosms containing different plant community compositions. The experiment was replicated at two sites, a colder mountainous upland site with high snow accumulation and a warmer and drier lowland site. Increased soil temperature variability enhanced soil biotic activity for both sites during winter, as indicated by 35% higher nitrogen (N) availability in the soil solution, 40% higher belowground decomposition and a 25% increase in the potential activity of the enzyme cellobiohydrolase. The mobilization of N differed between sites, and the 15N signal in leaves was reduced by 31% in response to winter warming pulses, but only at the cold site, with significant reductions occurring for three of four tested plant species at this site. Furthermore, there was a trend of increased N leaching in response to the recurrent winter warming pulses. Overall, projected winter climate change in the temperate zone, with less snow and more variable soil temperatures, appears important for shifts in ecosystem functioning (i.e. nutrient cycling). While the effects of warming pulses on plant N mobilization did not differ among sites, reduced plant 15N incorporation at the colder temperate site suggests that frost damage may reduce plant N uptake in a warmer world, with important implications for nitrogen cycling and nitrogen losses from ecosystems.

  6. Indoor air quality in typical temperate zone Australian dwellings

    Science.gov (United States)

    Molloy, S. B.; Cheng, M.; Galbally, I. E.; Keywood, M. D.; Lawson, S. J.; Powell, J. C.; Gillett, R.; Dunne, E.; Selleck, P. W.

    2012-07-01

    We report the results of a comprehensive study of indoor air quality in typical temperate zone Australian dwellings. Forty dwellings located over an 800 km2 area in the south-east of Melbourne with a range of ages, materials and structures representative of Australian dwellings were selected. A range of indoor air quality pollutants were sampled both inside and outside for one week each in Winter/Spring 2008 and Summer/Autumn 2009. Information was collected on house characteristics, the surrounding areas and occupant activities during the sampling. Weekly indoor averaged CO2 (536 ± 121 ppm), CO (0.3 ± 0.2 ppm), PM2.5 (8.4 ± 4.0 ?g m-3), temperatures (21.2 ± 2.0 °C), water vapour mixing ratios (7.9 ± 1.3 g kg-1), benzene (1.3 ± 1.1 ?g m-3), toluene (8.8 ± 7.9 ?g m-3) and xylenes (6.2 ± 6.7 ?g m-3) varied from 1.1 to approximately three times higher compared to the equivalent outdoors concentrations. Formaldehyde (12.2 ± 4.7 ppb), other carbonyls (7.9 ± 2.6 ppb) and total volatile organic compounds (181.1 ± 89.5 ?g m-3) had indoor concentrations of factors between eight and 12 times higher compared to outdoor concentrations. Weekly averaged indoor ozone (0.7 ± 0.7 ppb), NO2 (8.4 ± 3.9 ppb) and PM10 (20.4 ± 8.1 ?g m-3) were significantly lower than outdoors. Correlations and factor analysis showed the major influences on this indoor air quality were (a) dwelling age, whereby dwellings constructed in recent decades compared to older buildings were found to have increased concentrations of the highly elevated species formaldehyde, other carbonyls and total volatile organic compounds, and (b) combustion and cooking activities that increased the concentrations of multiple species including CO, CO2, NO2, H2O and particles. The indoor pollutant concentrations from this study were in general comparable with or lower than other Australian or overseas studies.

  7. Forecasting temperate alpine glacier survival from accumulation zone observations

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    M. S. Pelto

    2009-05-01

    Full Text Available For temperate alpine glaciers survival is dependent on the consistent presence of an accumulation zone. The lack of a consistent and persistent accumulation zone leads to substantial thinning of the glacier in the accumulation zone. Accumulation zone thinning is evident in satellite imagery or field observation based the emergence of new rock outcrops or the recession of the margin of the glacier in the accumulation zone along a substantial portion of its perimeter. In either case the accumulation zone is no longer functioning as an accumulation zone and survival is unlikely. In both the North Cascades and Wind River Range nine of the fifteen glaciers examined are forecast not to survive the current climate or future additional warming. The results vary considerably with adjacent glaciers having a different survival forecast. This emphasizes the danger of extrapolating survival from one glacier to the next. This trait also emphasizes the value of a simple forecasting tool that can be applied to all glaciers. The automated remote sensing based glacier classification schemes developed offer the potential for automating this process based on the changes in the glacier outline.

  8. Thermal performance of natural airflow window in subtropical and temperate climate zones - A comparative study

    International Nuclear Information System (INIS)

    Airflow window is highly useful in conserving building energy, and lessens the comfort problems caused by glazing. In this study, the thermal performance of a natural airflow window was examined through the use of a dynamic model, developed based on the integrated energy balance and airflow networks. The validity of the model was first tested by measured data obtained from a prototype installed at an environmental chamber. The application in the subtropical and temperate climate zones were then examined with the typical weather data of Hong Kong and Beijing. The findings confirmed that the natural airflow window can achieve substantial energy saving in both cities, and the reversible window frame is only required for Beijing, a location with hot summer and cold winter. The space cooling load via fenestration in Hong Kong, a subtropical city, can be reduced to 60% of the commonly used single absorptive glazing. In Beijing, as an example of the temperate climate, this can be reduced to 75% of the commonly used double glazing configuration in the summer period, and the space heat gain can be improved by 46% in the winter period.

  9. Controls on winter ecosystem respiration in temperate and boreal ecosystems

    Directory of Open Access Journals (Sweden)

    T. Wang

    2011-07-01

    Full Text Available Winter CO2 fluxes represent an important component of the annual carbon budget in northern ecosystems. Understanding winter respiration processes and their responses to climate change is also central to our ability to assess terrestrial carbon cycle and climate feedbacks in the future. However, the factors influencing the spatial and temporal patterns of winter ecosystem respiration (Reco of northern ecosystems are poorly understood. For this reason, we analyzed eddy covariance flux data from 57 ecosystem sites ranging from ~35° N to ~70° N. Deciduous forests were characterized by the highest winter Reco rates (0.90 ± 0.39 g C m?2 d?1, when winter is defined as the period during which daily air temperature remains below 0 °C. By contrast, arctic wetlands had the lowest winter Reco rates (0.02 ± 0.02 g C m?2 d?1. Mixed forests, evergreen needle-leaved forests, grasslands, croplands and boreal wetlands were characterized by intermediate winter Reco rates (g C m?2 d?1 of 0.70(±0.33, 0.60(±0.38, 0.62(±0.43, 0.49(±0.22 and 0.27(±0.08, respectively. Our cross site analysis showed that winter air (Tair and soil (Tsoil temperature played a dominating role in determining the spatial patterns of winter Reco in both forest and managed ecosystems (grasslands and croplands. Besides temperature, the seasonal amplitude of the leaf area index (LAI, inferred from satellite observation, or growing season gross primary productivity, which we use here as a proxy for the amount of recent carbon available for Reco in the subsequent winter, played a marginal role in winter CO2 emissions from forest ecosystems. We found that winter Reco sensitivity to temperature variation across space (QS was higher than the one over time (interannual, QT. This can be expected because QS not only accounts for climate gradients across sites but also for (positively correlated the spatial variability of substrate quantity. Thus, if the models estimate future warming impacts on Reco based on QS rather than QT, this could overestimate the impact of temperature changes.

  10. Changes in winter conditions impact forest management in north temperate forests.

    Science.gov (United States)

    Rittenhouse, Chadwick D; Rissman, Adena R

    2015-02-01

    Climate change may impact forest management activities with important implications for forest ecosystems. However, most climate change research on forests has focused on climate-driven shifts in species ranges, forest carbon, and hydrology. To examine how climate change may alter timber harvesting and forest operations in north temperate forests, we asked: 1) How have winter conditions changed over the past 60 years? 2) Have changes in winter weather altered timber harvest patterns on public forestlands? 3) What are the implications of changes in winter weather conditions for timber harvest operations in the context of the economic, ecological, and social goals of forest management? Using meteorological information from Climate Data Online and Autoregressive Integrated Moving Average (ARIMA) models we document substantial changes in winter conditions in Wisconsin, including a two- to three-week shortening of frozen ground conditions from 1948 to 2012. Increases in minimum and mean soil temperatures were spatially heterogeneous. Analysis of timber harvest records identified a shift toward greater harvest of jack pine and red pine and less harvest of aspen, black spruce, hemlock, red maple, and white spruce in years with less frozen ground or snow duration. Interviews suggested that frozen ground is a mediating condition that enables low-impact timber harvesting. Climate change may alter frozen ground conditions with complex implications for forest management. PMID:25463581

  11. Algal biomass and primary production within a temperate zone sandstone

    International Nuclear Information System (INIS)

    The use of dimethyl sulfoxide (DMSO) to extract chlorophyll a and 14C-labelled photosynthate from endolithic algae of sparsely vegetated, cold temperate grasslands on the Colorado Plateau in Arizona has yielded the first estimates of biomass and photosynthesis for this unusual community. These subsurface microorganisms are found widespread in exposed Coconino Sandstone, a predominant formation in this cold temperate region. The endolithic community in Coconino Sandstone, composed primarily of coccoid blue-green and coccoid/sarcinoid green algae, yielded a biomass value (as chlorophyll a content) of 87 mg m-2 rock surface area and a photosynthetic rate of 0.37 mg CO2 dm-2 hr-1 or 0.48 mg CO2 mg-1 chl a hr-1. The endolithic algal community contributes moderate biomass (5-10%) and substantial photosynthesis (20-80%) to the sparse grassland ecosystem

  12. Influence of tropical easterlies in southern Africa's winter rainfall zone during the Holocene

    Science.gov (United States)

    Chase, Brian M.; Lim, Sophak; Chevalier, Manuel; Boom, Arnoud; Carr, Andrew S.; Meadows, Michael E.; Reimer, Paula J.

    2015-01-01

    South Africa's southwestern Cape occupies a critical transition zone between Southern Hemisphere temperate (winter) and tropical (summer) moisture-bearing systems. In the recent geological past, it has been proposed that the relative influence of these systems may have changed substantially, but little reliable evidence regarding regional hydroclimates and rainfall seasonality exists to refine or substantiate the understanding of long-term dynamics. In this paper we present a mid-to late Holocene multi-proxy record of environmental change from a rock hyrax midden from Katbakkies Pass, located along the modern boundary between the winter and summer rainfall zones. Derived from stable carbon and nitrogen isotopes, fossil pollen and microcharcoal, these data provide a high resolution record of changes in humidity, and insight into changes in rainfall seasonality. Whereas previous work concluded that the site had generally experienced only subtle environmental change during the Holocene, our records indicate that significant, abrupt changes have occurred in the region over the last 7000 years. Contrary to expectations based on the site's location, these data indicate that the primary determinant of changes in humidity is summer rather than winter rainfall variability, and its influence on drought season intensity and/or length. These findings are consistent with independent records of upwelling along the southern and western coasts, which indicate that periods of increased humidity are related to increased tropical easterly flow. This substantially refines our understanding of the nature of temperate and tropical circulation system dynamics in SW Africa, and how changes in their relative dominance have impacted regional environments during the Holocene.

  13. Climate change and temperate zone insects: the tyranny of thermodynamics meets the world of limited resources.

    Science.gov (United States)

    Adamo, Shelley A; Baker, Jillian L; Lovett, Maggie M E; Wilson, Graham

    2012-12-01

    Climate change will result in warmer temperatures and an increase in the frequency and severity of extreme weather events. Given that higher temperatures increase the reproductive rate of temperate zone insects, insect population growth rates are predicted to increase in the temperate zone in response to climate. This consensus, however, rests on the assumption that food is freely available. However, under conditions of limited food, the reproductive output of the Texan cricket Gryllus texensis (Cade and Otte) was highest at its current normal average temperature and declined with increasing temperature. Moreover, low food availability decreased survival during a simulated heat wave. Therefore, the effects of climate change on this species, and possibly on many others, are likely to hinge on food availability. Extrapolation from our data suggests that G. texensis will show larger yearly fluctuations in population size as climate change continues, and this will also have ecological repercussions. Only those temperate zone insects with a ready supply of food (e.g., agricultural pests) are likely to experience the predicted increase in population growth in response to climate change; food-limited species are likely to experience a population decline. PMID:23321114

  14. Responses of the photosynthetic apparatus to winter conditions in broadleaved evergreen trees growing in warm temperate regions of Japan.

    Science.gov (United States)

    Tanaka, Chizuru; Nakano, Takashi; Yamazaki, Jun-Ya; Maruta, Emiko

    2015-01-01

    Photosynthetic characteristics of two broadleaved evergreen trees, Quercus myrsinaefolia and Machilus thunbergii, were compared in autumn and winter. The irradiance was similar in both seasons, but the air temperature was lower in winter. Under the winter conditions, net photosynthesis under natural sunlight (Anet) in both species dropped to 4 ?mol CO2 m(-2) s(-1), and the quantum yield of photosystem II (PSII) photochemistry in dark-adapted leaves (Fv/Fm) also dropped to 0.60. In both species the maximum carboxylation rates of Rubisco (V(cmax)) decreased, and the amount of Rubisco increased in winter. A decline in chlorophyll (Chl) concentration and an increase in the Chl a/b ratio in winter resulted in a reduction in the size of the light-harvesting antennae. From measurements of Chl a fluorescence parameters, both the relative fraction and the energy flux rates of thermal dissipation through other non-photochemical processes were markedly elevated in winter. The results indicate that the photosynthetic apparatus in broadleaved evergreen species in warm temperate regions responds to winter through regulatory mechanisms involving the downregulation of light-harvesting and photosynthesis coupled with increased photoprotective thermal energy dissipation to minimize photodamage in winter. These mechanisms aid a quick restart of photosynthesis without the development of new leaves in the following spring. PMID:25500451

  15. Winter warming delays dormancy release, advances budburst, alters carbohydrate metabolism and reduces yield in a temperate shrub

    Science.gov (United States)

    Pagter, Majken; Andersen, Uffe Brandt; Andersen, Lillie

    2015-01-01

    Global climate models predict an increase in the mean surface air temperature, with a disproportionate increase during winter. Since temperature is a major driver of phenological events in temperate woody perennials, warming is likely to induce changes in a range of these events. We investigated the impact of slightly elevated temperatures (+0.76 °C in the air, +1.35 °C in the soil) during the non-growing season (October–April) on freezing tolerance, carbohydrate metabolism, dormancy release, spring phenology and reproductive output in two blackcurrant (Ribes nigrum) cultivars to understand how winter warming modifies phenological traits in a woody perennial known to have a large chilling requirement and to be sensitive to spring frost. Warming delayed dormancy release more in the cultivar ‘Narve Viking’ than in the cultivar ‘Titania’, but advanced budburst and flowering predominantly in ‘Titania’. Since ‘Narve Viking’ has a higher chilling requirement than ‘Titania’, this indicates that, in high-chilling-requiring genotypes, dormancy responses may temper the effect of warming on spring phenology. Winter warming significantly reduced fruit yield the following summer in both cultivars, corroborating the hypothesis that a decline in winter chill may decrease reproductive effort in blackcurrant. Elevated winter temperatures tended to decrease stem freezing tolerance during cold acclimation and deacclimation, but it did not increase the risk of freeze-induced damage mid-winter. Plants at elevated temperature showed decreased levels of sucrose in stems of both cultivars and flower buds of ‘Narve Viking’, which, in buds, was associated with increased concentrations of glucose and fructose. Hence, winter warming influences carbohydrate metabolism, but it remains to be elucidated whether decreased sucrose levels account for any changes in freezing tolerance. Our results demonstrate that even a slight increase in winter temperature may alter phenological traits in blackcurrant, but to various extents depending on genotype-specific differences in chilling requirement. PMID:25802249

  16. Winter warming delays dormancy release, advances budburst, alters carbohydrate metabolism and reduces yield in a temperate shrub.

    Science.gov (United States)

    Pagter, Majken; Andersen, Uffe Brandt; Andersen, Lillie

    2015-01-01

    Global climate models predict an increase in the mean surface air temperature, with a disproportionate increase during winter. Since temperature is a major driver of phenological events in temperate woody perennials, warming is likely to induce changes in a range of these events. We investigated the impact of slightly elevated temperatures (+0.76 °C in the air, +1.35 °C in the soil) during the non-growing season (October-April) on freezing tolerance, carbohydrate metabolism, dormancy release, spring phenology and reproductive output in two blackcurrant (Ribes nigrum) cultivars to understand how winter warming modifies phenological traits in a woody perennial known to have a large chilling requirement and to be sensitive to spring frost. Warming delayed dormancy release more in the cultivar 'Narve Viking' than in the cultivar 'Titania', but advanced budburst and flowering predominantly in 'Titania'. Since 'Narve Viking' has a higher chilling requirement than 'Titania', this indicates that, in high-chilling-requiring genotypes, dormancy responses may temper the effect of warming on spring phenology. Winter warming significantly reduced fruit yield the following summer in both cultivars, corroborating the hypothesis that a decline in winter chill may decrease reproductive effort in blackcurrant. Elevated winter temperatures tended to decrease stem freezing tolerance during cold acclimation and deacclimation, but it did not increase the risk of freeze-induced damage mid-winter. Plants at elevated temperature showed decreased levels of sucrose in stems of both cultivars and flower buds of 'Narve Viking', which, in buds, was associated with increased concentrations of glucose and fructose. Hence, winter warming influences carbohydrate metabolism, but it remains to be elucidated whether decreased sucrose levels account for any changes in freezing tolerance. Our results demonstrate that even a slight increase in winter temperature may alter phenological traits in blackcurrant, but to various extents depending on genotype-specific differences in chilling requirement. PMID:25802249

  17. Use of the Dynamic Model for the Assessment of Winter Chilling in a Temperate and a Subtropical Climatic Zone of Chile Utilización del Modelo Dinámico para Evaluar el Frío Invernal en una Localidad de Clima Templado y otra Subtropical de Chile

    Directory of Open Access Journals (Sweden)

    Francisco J Pérez

    2008-06-01

    Full Text Available Accumulated chilling was estimated by applying three different models to the hourly autumn-winter temperature records from Santiago (33°34 S lat; 625 m.a.s.l. and Vicuña (30°02´ S lat; 643 m.a.s.l. for the years 2005 and 2006. The model of chilling hours, currently used in Chile as an agroclimatic indicator, was of limited use for effectively contrasting a subtropical condition (Vicuña with a temperate area such as Santiago. The application of the Utah model gave negative values from March to May, and even up to June in Vicuña, since in this model the chilling effect is “negated” by warmer temperatures. However, a modified version of the Utah model named Positive Chilling Units (PCU, in which negative values are omitted, showed differences in the accumulated chilling between both regions, although these differences were of small magnitude and were noted only from July onwards. The Dynamic Model, which considers that chilling is irreversibly accumulated as quantum or Chill Portions (CP, showed that chilling in Santiago doubled that of Vicuña, and that these differences in location were already expressed at the beginning of autumn, confirming, thus, the suitability of the model for subtropical conditions. In this work the advantages of the dynamic model over other models are discussed.Se evaluó el frío invernal acumulado en Santiago (33°34´ lat. Sur; 625 m.s.n.m.; Región Metropolitana y Vicuña (30°02´ lat. Sur; 643 m.s.n.m.; Región de Coquimbo durante las temporadas 2005 y 2006 aplicando tres diferentes modelos. El modelo de horas-frío (CH, actualmente empleado como indicador agroclimático en Chile, resultó de poca utilidad para contrastar efectivamente la condición subtropical de Vicuña con la condición templada de Santiago. Al utilizar el modelo de Utah se obtuvieron valores negativos de marzo a mayo e incluso hasta el mes de junio en Vicuña, ya que, precisamente, con este modelo el efecto del frío es anulado por las altas temperaturas. Sin embargo, una modificación de este modelo, denominado Unidades de Frío Positivas (UPF, en que los valores negativos se omiten, mostró diferencias en el frío acumulado entre ambas regiones, pero las diferencias fueron pequeñas y se expresaron sólo a partir del mes de julio en adelante. La aplicación del Modelo Dinámico, que considera que el frío se acumula en forma irreversible, como quantum o Porciones de Frío (PF, mostró que el frío invernal acumulado en la Región Metropolitana es el doble que en la Región de Coquimbo, y que las diferencias se expresan desde los inicios del otoño, haciéndolo así particularmente aplicable para zonas subtropicales. En este trabajo se discuten las ventajas del modelo dinámico por sobre los otros modelos utilizados.

  18. Conference on the Rehabilitation of Severely Damaged Land and Freshwater Ecosystems in Temperate Zones

    CERN Document Server

    Woodman, M

    1978-01-01

    This volume contains the papers presented at a conference on "The rehabilitation of severely damaged land and freshwater eco­ systems in temperate zones", held at Reykjavik, Iceland, from 4th to 11th July, 1976. The meeting was held under the auspices of the Ecosciences Panel of the N.A.T.O. Science Committee, and the organising expenses and greater part of the expenses of the speakers and chairmen were provided by N.A.T.O. The scientific programme was planned by M. W. Holdgate and M. J. Woodman, in consultation with numerous colleagues, and especially with the Administrative Director of the Conference in Iceland, Dr. Sturla Fridriksson. Iceland proved a particularly suitable location for such a Conference. Geologically, it is one of the youngest countries 1n the world, owing its origin to the up-welling of volcanic rock along the spreading zone of the mid-Atlantic ridge within the past 20 million years. Its structure, northern oceanic situation, recent glaciation and continuing volcanic activity make it dis...

  19. Precipitation variability in the winter rainfall zone of South Africa during the last 1400 yr linked to the austral westerlies

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    J. C. Stager

    2012-05-01

    Full Text Available The austral westerlies strongly influence precipitation and ocean circulation in the southern temperate zone, with important consequences for cultures and ecosystems. Global climate models anticipate poleward retreat of the austral westerlies with future warming, but the available paleoclimate records that might test these models have been limited to South America and New Zealand, are not fully consistent with each other and may be complicated by influences from other climatic factors. Here we present the first high-resolution diatom and sedimentological records from the winter rainfall region of South Africa, representing precipitation in the equatorward margin of the westerly wind belt during the last 1400 yr. Inferred rainfall was relatively high ?1400–1200 cal yr BP, decreased until ?950 cal yr BP, and rose notably through the Little Ice Age with pulses centred on ?600, 530, 470, 330, 200, 90, and 20 cal yr BP. Synchronous fluctuations in Antarctic ice core chemistry strongly suggest that these variations were linked to changes in the westerlies. Equatorward drift of the westerlies during the wet periods may have influenced Atlantic meridional overturning circulation by restricting marine flow around the tip of Africa. Apparent inconsistencies among some aspects of records from South America, New Zealand and South Africa warn against the simplistic application of single records to the Southern Hemisphere as a whole. Nonetheless, these findings in general do support model projections of increasing aridity in the austral winter rainfall zones with future warming.

  20. Precipitation variability in the winter rainfall zone of South Africa during the last 1400 yr linked to the austral westerlies

    Science.gov (United States)

    Stager, J. C.; Mayewski, P. A.; White, J.; Chase, B. M.; Neumann, F. H.; Meadows, M. E.; King, C. D.; Dixon, D. A.

    2012-05-01

    The austral westerlies strongly influence precipitation and ocean circulation in the southern temperate zone, with important consequences for cultures and ecosystems. Global climate models anticipate poleward retreat of the austral westerlies with future warming, but the available paleoclimate records that might test these models have been limited to South America and New Zealand, are not fully consistent with each other and may be complicated by influences from other climatic factors. Here we present the first high-resolution diatom and sedimentological records from the winter rainfall region of South Africa, representing precipitation in the equatorward margin of the westerly wind belt during the last 1400 yr. Inferred rainfall was relatively high ?1400-1200 cal yr BP, decreased until ?950 cal yr BP, and rose notably through the Little Ice Age with pulses centred on ?600, 530, 470, 330, 200, 90, and 20 cal yr BP. Synchronous fluctuations in Antarctic ice core chemistry strongly suggest that these variations were linked to changes in the westerlies. Equatorward drift of the westerlies during the wet periods may have influenced Atlantic meridional overturning circulation by restricting marine flow around the tip of Africa. Apparent inconsistencies among some aspects of records from South America, New Zealand and South Africa warn against the simplistic application of single records to the Southern Hemisphere as a whole. Nonetheless, these findings in general do support model projections of increasing aridity in the austral winter rainfall zones with future warming.

  1. Controlling Factors of Root-Zone Soil Moisture Spectra in Tropical and Temperate Forests

    Science.gov (United States)

    Nakai, T.; Katul, G. G.; Kotani, A.; Igarashi, Y.; Ohta, T.; Kumagai, T.

    2014-12-01

    Characteristics of root-zone soil moisture spectra in a subtropical monsoon forest in Thailand (Mae Moh) and two warm-temperate forests in the US (Duke) and Japan (Seto) were examined for time scales ranging from 30 minutes to multiple years. These forested areas have comparable maximum leaf area index but markedly different phase relations between evapotranspiration, net radiation, precipitation, and soil moisture. A hierarchy of models that sequentially introduce the spectrum of precipitation, net radiation, and nonlinearites in the damping originating from stomatal controls and drainage losses were used. If the precipitation is random, and the damping term by evapotranspiration and drainage is increased linearly with increasing soil moisture, the temporal variability of soil moisture simplifies to a first order Markov process commonly employed in the analysis of soil moisture in climate models. Its spectrum exhibits a Lorentz function with a white-noise behavior at low frequency and red-noise behavior at high frequency separated by a time-scale constant for intermediate frequencies. Such first order Markov process model with its time scale defined by the maximum wet surface evapotranspiration, soil porosity, and root-zone depth did not represent the observed soil moisture spectra at all three sites. Adding the effect of precipitation and net radiation variability were necessary for representing the actual soil moisture spectra. While the observed soil moisture spectra were satisfactorily reproduced by these additions, the relative importance of precipitation and net radiation to the soil moisture spectra differed between sites. The soil moisture memory, inferred from the observed soil moisture spectra (model decay time scale), was about 25-38 days, which was larger than that determined from maximum wet evapotranspiration and available pore space alone, except that these two time scales in Seto forest were nearly the same.

  2. Geographic variation in the age of temperate-zone reptile and amphibian species: Southern Hemisphere species are older

    OpenAIRE

    Dubey, Sylvain; Shine, Richard

    2010-01-01

    Despite controversy over alternative definitions, the species is the fundamental operational unit of biodiversity, and species are the building-blocks of conservation. But is a ‘species’ from one part of the world the same as a ‘species’ from elsewhere? Our meta-analysis of molecular phylogenetic data reveals that reptile and amphibian species distributed in temperate-zone areas of the Northern Hemisphere are younger than taxa from the Southern Hemisphere, probably reflecting the grea...

  3. Interactions between seasonality and oceanic forcing drive the phytoplankton variability in the tropical-temperate transition zone (~ 30°S) of Eastern Australia

    Science.gov (United States)

    Armbrecht, Linda H.; Schaeffer, Amandine; Roughan, Moninya; Armand, Leanne K.

    2015-04-01

    The East Australian Current (EAC) has been shown to be warming rapidly, which is expected to cause latitudinal shifts in phytoplankton abundance, distribution and composition along the east Australian coast. Yet a lack of phytoplankton information exists northward of 34°S. Here, we provide the first detailed taxonomic time-series survey (monthly sampling for about one annual cycle, 2011-2012) in the east Australian tropical-temperate transition zone (~ 30°S, upstream of the EAC separation point at ~ 31-32°S). All phytoplankton (categorised depending on their association with specific water-types) show a seasonal signal with abundance maxima (minima) during summer (winter). This seasonal signal is most pronounced in the seasonal/bloom category and least expressed by deep-water taxa, which prefer cold, saline and dense bottom water independent of the season. Different extents of EAC encroachment onto the continental shelf drive the cross-shelf phytoplankton composition and distribution, such that a weak EAC is associated with phytoplankton community being organised along 'depth' and 'distance from the coast' gradients with high phytoplankton abundances inshore. A strong EAC favours the occurrence of warm-water taxa offshore and an increase in diatom abundance on the mid-shelf (53% shelf width). We conclude that the phytoplankton community in the tropical-temperate transition zone of Eastern Australia is driven by an interaction of intrinsic seasonal cycles and primarily EAC-driven oceanic forcing. Our findings benefit studies located in Western Boundary Current systems worldwide, in which warming and strengthening of these currents are predicted to severely impact phytoplankton dynamics.

  4. Challenges in the nutrition and management of herbivores in the temperate zone.

    Science.gov (United States)

    van Vuuren, A M; Chilibroste, P

    2013-03-01

    The expected higher global demand for animal proteins and the competition for starch and sugars between food, fuel and feed seem to favour herbivores that convert solar energy captured in fibrous plants into animal products. However, the required higher production level of herbivores questions the sustainability of this conversion. An increase in herbivore production can be achieved by increasing the number of animals associated with the increasing demand of plant biomass or by improving the efficiency with which plant biomass is converted into meat and milk. The potential to increase food production by cattle, the main food-producing herbivore in the temperate zones outside China, was considered in three production systems: grassland-based, mixed rain-fed and mixed irrigated systems. The potential to increase plant biomass production in grassland-based systems seems limited, unless fertiliser is imported in large quantities and crop production is increased, sacrificing valuable, high-quality grasslands, which often conflicts with sustainable production methods. Also, in mixed systems with high inputs of fertiliser or water, improvements in plant biomass production seem marginal and the main challenges for these systems are in breeding high-quality plant biomass at lower levels of fertiliser and the use of new co-products from food processing and bio-based economies. Consequently, the main challenge in herbivore nutrition management is to improve the efficiency of plant biomass utilisation. Stocking rate management along with seasonal variation in the grazing capacity of grasslands and moderate use of fertiliser may increase meat production in grassland-based systems by 400%. Improving plant biomass utilisation in the more industrialised mixed rain-fed systems seems possible by better feed storage technologies and for dairy cattle by improving animal health and lifetime production level. Managing the transition period seems crucial to achieve more sustainable mixed rain-fed and mixed irrigated dairy production systems. Whether sustainable production methods will be implemented also depends on macro-economic conditions and awareness of regional and global environmental concerns. PMID:23031652

  5. Effects of winter temperature and summer drought on net ecosystem exchange of CO2 in a temperate peatland

    Science.gov (United States)

    Helfter, Carole; Campbell, Claire; Dinsmore, Kerry; Drewer, Julia; Coyle, Mhairi; Anderson, Margaret; Skiba, Ute; Nemitz, Eiko; Billett, Michael; Sutton, Mark

    2014-05-01

    Northern peatlands are one of the most important global sinks of atmospheric carbon dioxide (CO2); their ability to sequester C is a natural feedback mechanism controlled by climatic variables such as precipitation, temperature, length of growing season and period of snow cover. In the UK it has been predicted that peatlands could become a net source of carbon in response to climate change with climate models predicting a rise in global temperature of ca. 3oC between 1961-1990 and 2100. Land-atmosphere exchange of CO2in peatlands exhibits marked seasonal and inter-annual variations, which have significant short- and long-term effects on carbon sink strength. Net ecosystem exchange (NEE) of CO2 has been measured continuously by eddy-covariance (EC) at Auchencorth Moss (55° 47'32 N, 3° 14'35 W, 267 m a.s.l.), a temperate peatland in central Scotland, since 2002. Auchencorth Moss is a low-lying, ombrotrophic peatland situated ca. 20 km south-west of Edinburgh. Peat depth ranges from 5 m and the site has a mean annual precipitation of 1155 mm. The vegetation present within the flux measurement footprint comprises mixed grass species, heather and substantial areas of moss species (Sphagnum spp. and Polytrichum spp.). The EC system consists of a LiCOR 7000 closed-path infrared gas analyser for the simultaneous measurement of CO2 and water vapour and of a Gill Windmaster Pro ultrasonic anemometer. Over the 10 year period, the site was a consistent yet variable sink of CO2 ranging from -34.1 to -135.9 g CO2-C m-2 yr-1 (mean of -69.1 ± 33.6 g CO2-C m-2 yr-1). Inter-annual variability in NEE was positively correlated to the length of the growing seasons and mean winter air temperature explained 93% of the variability in summertime sink strength, indicating a phenological memory-effect. Plant development and productivity were stunted by colder winters causing a net reduction in the annual carbon sink strength of this peatland where autotrophic processes are thought to be dominant. The site is wet throughout most of the year (water table depth confounding adverse effects of drought and winter climate on GPP is thus not straightforward. Whilst 2010 had the smallest NEE in the 2002-2012 period, the largest values were found for years with warm winters and relatively wet growing seasons. A simple parameterisation of the effects of PAR on GPP of and air temperature on ecosystem respiration, suggest that a rise in air temperature of 1° C between 2012 and 2065 could lead to a 73% increase in the carbon sink strength of the peatland, provided hydrological conditions remain unchanged. This demonstrates that climate change is not likely to change this peatland into a carbon source by 2100.

  6. The impacts of climate change on the winter hardiness zones of woody plants in Europe

    Science.gov (United States)

    Gloning, Philipp; Estrella, Nicole; Menzel, Annette

    2013-08-01

    In this study, we investigated how global climate change will affect winter minimum temperatures and if, as a consequence, potential species ranges will expand or contract. Thus, Heinze and Schreiber's 1984 winter hardiness zones (WHZ) for woody plants in Europe, which are based on mean annual minimum temperatures, were updated and analyzed for recent and future changes using the ENSEMBLES data set E-OBS for recent climate and CLM-model data based on two emission scenarios (A1B and B1) for future simulated climate. For the different data sets, maps of the WHZ were created and compared. This allowed the assessment of projected changes in the development of the WHZ until the end of the twenty-first century. Our results suggested that, depending on the emission scenario used, the main shifts in the WHZ will occur for zones 8 and 9 (increase), located in Mediterranean regions, and for zone 5 (decrease), a boreal zone. Moreover, up to 85 % of the area analyzed will experience a warmer winter climate during the twenty-first century, and some areas will experience increases in two WHZ, equal to an increase of 5.6-11 °C in the mean annual minimum temperature. The probabilities of absolute minimum winter temperatures for four 30-year time periods from 1971 to 2100 were calculated in order to reveal changes associated with a general increase in temperature as well as shifts in the distribution itself. It was predicted that colder temperatures than indicated by the WHZ will occur less frequently in the future, but, depending on the region, reoccur every 5-50 years. These findings are discussed in the context of woody plant species assigned to each of the WHZ by Roloff and Bärtels (1996), with respect to a possible expansion of their range limits and the altered risk of recurring cold spells.

  7. Recovery of coastal ecosystems after large tsunamis in various climatic zones - review of cases from tropical, temperate and polar zones (Invited)

    Science.gov (United States)

    Szczucinski, W.

    2013-12-01

    Large tsunamis cause significant changes in coastal ecosystems. They include modifications in shoreline position, sediment erosion and deposition, new initial soil formation, salination of soils and waters, removal of vegetation, as well as direct impact on humans and infrastructure. The processes and rate of coastal zone recovery from large tsunamis has been little studied but during the last decade a noteworthy progress has been made. This study focus on comparison of recovery processes in various climatic zones, namely in monsoonal-tropical, temperate and polar zone. It is based on own observation and monitoring in areas affected by 2004 Indian Ocean Tsunami in Thailand, 2011 Tohoku-oki tsunami in Japan and 2000 Paatuut landslide-generated tsunami in Vaigat Strait (west Greenland), as well as on review of published studies from those areas. The particular focus is on physical and biological recoveries of beaches, recovery of coastal vegetation, new soil formation in eroded areas and those covered by tsunami deposits, marine salt removal from soils, surface- and groundwater, as well as landscape adjustment after the tsunamis. The beach zone - typically the most tsunami-eroded zone, has been recovered already within weeks to months and has been observed to be in the pre-tsunami equilibrium stage within one year in all the climate zones, except for sediment-starved environments. The existing data on beach ecosystems point also to relatively fast recovery of meio- and macrofauna (within weeks to several months). The recovery of coastal vegetation depends on the rate of salt removal from soils or on the rate of soil formation in case of its erosion or burial by tsunami deposits. The salt removal have been observed to depend mainly on precipitation and effective water drainage. In tropical climate with seasonal rainfall of more 3000 mm the salt removal was fast, however, in temperate climate with lower precipitation and flat topography the salinities still exceeded the recommended concentrations for freshwater plants after one year. The new soil formation and vegetation recovery depends mainly on the rate of biological production. In tropical climate the vegetation largely recovered already after the first rainy season and supported the new soil formation. In temperate climate this process was much slower, in particular in flat lying areas and on coastal dunes with poor sandy soils. In polar climate only limited vegetation recovery (mainly of Salix species) has been observed after 12 years and vegetation withered due to salt stress still marked the tsunami inundation limit and the new soil formation was very slow and focused on low lying, wet areas buried with thin tsunami deposits cover. The post-tsunami recovery processes may be grouped into climate-related (vegetation recovery, removal of salts from soils) and non climate-related (e.g. beach recovery) or modified by climatic and local factors (for instance, the rate of tsunami deposits reworking and thus new soil formation). The rate of recovery varies from days / weeks as in case of beach recovery to several decades as in case of new soil formation on tsunami deposits. The study was partly funded by Polish National Science Centre grant No. 2011/01/B/ST10/01553. The review results from studies in collaboration with number of researchers from Australia, Japan, Poland, Thailand, United Kingdom and United States to whom I express sincere thanks.

  8. Influence of the sea surface temperature conditions in the Pacific subarctic frontal zone on the pink salmon's winter survival ability

    Science.gov (United States)

    Tananaeva, Yu. N.

    2008-06-01

    Similar to other high-latitude ocean basins, the subarctic Pacific exhibits strong seasonal and inter-annual variations in the abiotic factors of the environment, which, in turn, strongly influence biological objects. One of the principal factors of this kind is the temperature regime. For our research, we chose pink salmon because more than 90% of its natural mortality occurs precisely during the wintering period. The lifetime of pink salmon is only one year, and the conditions of their populations reflect the thermal regime of the given year. The main wintering area of Asian pink salmon is the part of the subarctic frontal zone located south of the Aleutian Islands (43° 46°N). This region features sufficiently high wintertime concentrations of chlorophyll a and temperature conditions favorable for pink salmon wintering. The interannual temperature variability in the frontal zone is close to zero, and the width of the frontal zone may significantly change depending on the winter severity. In “milder” winters, the area of wintering extends, while, in “severe” winters, it is rather narrow, the forage base for fish decreases, they become more accessible for predators, and their survival rates sharply drop.

  9. Effect of low winter temperatures on milk production of dairy cows grazed on farms in a warm temperate climate (Australia)

    Science.gov (United States)

    Dragovich, D.

    1980-06-01

    Two-day milk production figures for dairymen at Armidale (31° S Lat.) and Goulburn (35° S Lat.), Australia, were compared with minimum daily temperatures. Comparisons were made between production levels on days with temperatures above and below 0°C, and between days with varying intensities of cold: differences in production were minor. The infrequent, more prolonged periods of cold weather (“cold” being days on which the minimum temperature was below 0°C) were also associated with only very slight reductions in milk output; and the most pronounced decline in production was not attributable to low temperatures. Although short-term fluctuations in output were not related to low temperature events or low temperatures in combination with rain, thermal stress on plant growth during winter contributed to a seasonal downturn in production and below-average annual milk yields in areas with low winter temperatures.

  10. The Impact of Winter and Spring Temperatures on Temperate Tree Budburst Dates: Results from an Experimental Climate Manipulation

    OpenAIRE

    Fu, Yongshuo H.; Campioli, Matteo; Deckmyn, Gaby; Janssens, Ivan A.

    2012-01-01

    Budburst phenology is a key driver of ecosystem structure and functioning, and it is sensitive to global change. Both cold winter temperatures (chilling) and spring warming (forcing) are important for budburst. Future climate warming is expected to have a contrasting effect on chilling and forcing, and subsequently to have a non-linear effect on budburst timing. To clarify the different effects of warming during chilling and forcing phases of budburst phenology in deciduous trees, (i) we cond...

  11. 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 of CH4 oxidation and that summer droughts may increase the soil CH4 sink of temperate forest soils. ?? 2005 Elsevier Ltd. All rights reserved.

  12. Winter

    OpenAIRE

    Liang, Bibo

    2009-01-01

    The film has won various documentary prizes in in China. It is located at the edge of the Minshan mountain ranges in southwest China. It looks at a peasant farming family over one winter. The credits at the end give the details. Permission has been given by the producer and director LIANG Bibo. Uploaded by Alan Macfarlane.

  13. Relation of Chlorophyll Fluorescence Sensitive Reflectance Ratios to Carbon FluxMeasurements ofMontanne Grassland and Norway Spruce Forest Ecosystems in the Temperate Zone.

    Czech Academy of Sciences Publication Activity Database

    A?, Alexander; Malenovský, Z.; Urban, Otmar; Hanuš, Jan; Zitová, Martina; Navrátil, M.; Vráblová, M.; Olejní?ková, Julie; Špunda, V.; Marek, Michal V.

    2012-01-01

    Ro?. 2012, ?. 2012 (2012), s. 1-13. ISSN 1537-744X R&D Projects: GA MŽP(CZ) SP/2D1/70/08; GA MŽP(CZ) SP/2D1/93/07; GA MŠk(CZ) LM2010007; GA MŠk(CZ) ED1.1.00/02.0073 Institutional research plan: CEZ:AV0Z60870520 Keywords : Chlorophyll fluorescence * carbon flux * forest ecosystems * Norway Spruce * temperate zone Subject RIV: EH - Ecology, Behaviour Impact factor: 1.730, year: 2012

  14. Root and soil carbon distribution at shoulderslope and footslope positions of temperate toposequences cropped to winter wheat

    DEFF Research Database (Denmark)

    Chirinda, Ngoni; Roncossek, Svenja Doreen

    2014-01-01

    Crop root residues are an important source of soil organic carbon (SOC) in arable systems. However, the spatial distribution of root biomass in arable systems remains largely unknown. In this study, we determined the spatial distribution of macro-root and shoot biomass of winter wheat at shoulderslope and footslope positions from four cultivated slopes within an arable field in western Denmark. In addition, soils from the shoulderslope and footslope positions of four slopes were characterized for physical and chemical properties. Root biomass dry matter (DM) was marginally higher (P = 0.06) at footslope (1.2 Mg DM ha- 1) than at shoulderslope positions (0.9 Mg DM ha? 1), in particular in the subsoil. Likewise shoot biomass was higher (P = 0.03) at footslope (10.3 Mg DM ha? 1) compared to shoulderslope (7.1 Mg DM ha? 1) positions. Soil bulk density increased with depth at shoulderslope positions, but was more variable with depth at footslope positions. Root C was significantly correlated with SOC in shoulderslope soils (r = 0.98), but not in footslope soils. We conclude that, at shoulderslope positions, SOC originated mainly from root residues whereas at footslope positions, SOC was derived from both root residues and likely soil redistribution processes. Management practices that increase C input at shoulderslope positions potentially enhance soil carbon storage and increase crop productivity, which would probably not be the case for C rich footslope soils. These findings imply that models used to simulate or predict C dynamics and crop productivity should consider topography-controlled variations in root C input and SOC redistribution as well as their effects on soil properties, root growth and crop productivity.

  15. Holocene climate variability in the Winter Rainfall Zone of South Africa

    Directory of Open Access Journals (Sweden)

    S. Weldeab

    2013-05-01

    Full Text Available We established a multi-proxy time series comprising analyses of major elements in bulk sediments, Sr and Nd isotopes and grain size of terrigenous fraction, and ?18O and ?13C in tests of Neogloboquadrina pachyderma (sinistral from a marine sediment sequence recovered off the Orange River. The records reveal coherent patterns of variability that reflect changes in wind strength, precipitation over the river catchments, and upwelling of cold and nutrient-rich coastal waters off western South Africa. The wettest episode of the Holocene in the Winter Rainfall Zone (WRZ of South Africa occurred during the "Little Ice Age" (700–100 yr BP. Wet phases were accompanied by strengthened coastal water upwellings, a decrease of Agulhas water leakage into the southern Atlantic, and a reduced dust incursion over Antarctica. A continuous aridification trend in the WRZ and a weakening of the southern Benguela Upwelling System (BUS between 9000 and 5500 yr BP parallel with increase of dust deposition over Antarctica and an enhanced leakage of warm Agulhas water into the southeastern Atlantic. The temporal relationship between precipitation changes in the WRZ, the thermal state of the coastal surface water, and leakage of warm water in southern Atlantic, and variation of dust incursion over Antarctica suggests a causal link that most likely was related to latitudinal shifts of the Southern Hemisphere westerlies. Our results of the mid-Holocene time interval may serve as an analogue to a possible long-term consequence of the current and future southward shift of the westerlies that may result in a decline of rainfall over southwest Africa and a weakened upwelling with implication for phytoplankton productivity and fish stocks. Furthermore, warming of the coastal surface water as a result of warm Agulhas water incursion into the southern BUS may affect coastal fog formation that is critical as moisture source for the endemic flora of the Namaqualand.

  16. Effect of chemical composition of 10GN2MFA steel and grain size on mechanical properties of metal of heat affected zone on tempering

    International Nuclear Information System (INIS)

    A study was made on the effect of variation of chemical composition of heat-resistant 10GN2MFA steel on mechanical properties of metal of heat affected zone at tempering temperature. Possibility of compensating the influence of alloying and impurity elements on tendency to crack formation on repeated heating (CRH) by grain grinding in large-grain section of overheating was investigated. It is shown that application of parametric equations for evaluation of tendency of steels of different chemical compositions to CRH is limited, because these equations don't enable to evaluate the combined effect of all chemical elements, conditioned by interaction of processes of dispersion hardening, impurity segregation and creep under stress relaxation

  17. Community structure and trophic ecology of zooplankton in the scotia sea marginal ice zone in winter (1988)

    Science.gov (United States)

    Hopkins, Thomas L.; Lancraft, Thomas M.; Torres, Joseph J.; Donnelly, Joseph

    1993-01-01

    Zooplankton community structure and trophic ecology were investigated in the marginal ice zone of the Southern Scotia Sea during the austral winter of 1988 as part of the AMERIEZ program. In the study area, near the South Orkneys (34-49°W, 57-61.5°S), water emerging from the Weddell Sea mixed with Scotia Sea water to form a complex field of mesoscale eddies and meanders. Three primary zooplankton communities were identified: a shallow cold water assemblage typical of Weddell Sea water; a shallow/upper mesopelagic assemblage of subantarctic species introduced into the southern Scotia Sea with warm core eddies from the Polar Front; and a deep (>400 m) mesopelagic community with circumtantartic species. Zooplankton numerical dominants were cyclopoid copepods (mostly Oithona spp.); biomass dominants were four calanoid copepods, Calanoides acutus, Rhincalanus gigas, Calanus propinquus and Metridia gerlachei. Calanoides acutus and R. gigas were undergoing winter diapause in the mesopelagic zone (>400 m) whereas M. gerlachei and C. propinquus were distributed throughout the water column. In the subantarctic eddies M. gerlachei was replaced by M. lucens as a dominant and R. gigas was more abundant than in cold water to the south. Diet analysis of 35 dominant species revealed five feeding guilds among the zooplankton. One consisted primarily of small herbivorous copepods. Two closely related guilds consisting of copepods, krill and salps were omnivorous, feeding on phytoplankton, protozoans, metazoans and crustacean debris (molts). Two guilds were constituted by predatory copepods and chaetognaths. A sixth group, all copepods, which included important numerical and biomass dominants of the region, was trophically inactive. A comparison of gut fullness between winter 1988 and fall 1986 revealed that all but two of 19 small particle grazing species had significantly less food in their guts in winter. The exceptions were the biomass dominants C. propinquus and M. gerlachei, which were actively feeding in winter. Phytoplankton biomass was low in winter, averaging two-thirds that in fall. Several major trophic pathways from phytoplankton through apex predators (birds and mammals) are proposed for winter in the southern Scotia Sea with zooplankton playing a central role in each.

  18. Holocene climate variability in the winter rainfall zone of South Africa

    Directory of Open Access Journals (Sweden)

    S. Weldeab

    2012-06-01

    Full Text Available We established a multi-proxy time series comprising analyses of major elements in bulk sediments, Sr and Nd isotopes, grain size of terrigenous fraction, and ?18O and ?13C in tests of Neogloboquadrina pachyderma (sinistral from a marine sediment sequence recovered off the Orange River. The records reveal coherent patterns of variability that reflect changes in wind strength, precipitation over the river catchments, and upwelling of cold and nutrient-rich coastal waters off Western South Africa. The wettest episode of the Holocene in the Winter Rainfall Zone (WRZ of South Africa occurred during the "Little Ice Age" (700–100 yr BP. Wet phases were accompanied by strengthened coastal water upwellings, a decrease of Agulhas water leakage into the Southern Atlantic, and a reduced dust incursion over Antarctica. A continuous aridification trend in the WRZ and a weakening of the Southern Benguela Upwelling System (BUS between 9000 and 5500 yr BP parallel with evidence of a poleward shift of the austral mid-latitude westerlies and an enhanced leakage of warm Agulhas water into the Southeastern Atlantic. The temporal relationship between precipitation changes in the WRZ, the thermal state of the coastal surface water, and variation of dust incursion over Antarctica suggests a causal link that most likely was related to latitudinal shifts of the Southern Hemisphere westerlies and changes in the amount of Agulhas water leakage into the Southern BUS. Our results of the mid-Holocene time interval may serve as an analogue to a possible long-term consequence of the current and future southward shift of the westerlies that may result in a decline of rainfall over Southwest Africa and a weakened upwelling with implication for phytoplankton productivity and fish stocks. Furthermore, warming of the coastal surface water as a result of warm Agulhas water incursion into the Southern BUS may affect coastal fog formation that is critical as moisture source for the endemic flora of the Namaqualand.

  19. Seasonal and Interseasonal Dynamics of Bluetongue Virus Infection of Dairy Cattle and Culicoides sonorensis Midges in Northern California – Implications for Virus Overwintering in Temperate Zones

    Science.gov (United States)

    Mayo, Christie E.; Mullens, Bradley A.; Reisen, William K.; Osborne, Cameron J.; Gibbs, E. Paul J.; Gardner, Ian A.; MacLachlan, N. James

    2014-01-01

    Bluetongue virus (BTV) is the cause of an economically important arboviral disease of domestic and wild ruminants. The occurrence of BTV infection of livestock is distinctly seasonal in temperate regions of the world, thus we determined the dynamics of BTV infection (using BTV-specific real time reverse transcriptase polymerase chain reaction) among sentinel cattle and vector Culicoides sonorensis (C. sonorensis) midges on a dairy farm in northern California throughout both the seasonal and interseasonal (overwintering) periods of BTV activity from August 2012 until March 2014. The data confirmed widespread infection of both sentinel cattle and vector midges during the August – November period of seasonal BTV transmission, however BTV infection of parous female midges captured in traps set during daylight hours also was detected in February of both 2013 and 2014, during the interseasonal period. The finding of BTV-infected vector midges during mid-winter suggests that BTV may overwinter in northern California by infection of long-lived female C. sonorensis midges that were infected during the prior seasonal period of virus transmission, and reemerged sporadically during the overwintering period; however the data do not definitively preclude other potential mechanisms of BTV overwintering that are also discussed. PMID:25215598

  20. Patrones geográficos de distribución de árboles y arbustos en la zona de transición climática mediterráneo-templada de Chile / Geographic patterns of distribution of trees and shrubs in the transitional Mediterranean-temperate climatic zone of Chile

    Scientific Electronic Library Online (English)

    ERNESTO A., TENEB; LOHENGRIN A., CAVIERES; MARÍA JOSÉ, PARRA; ALICIA, MARTICORENA.

    2004-03-01

    Full Text Available Uno de los principales objetivos de la biogeografía es determinar si las especies se distribuyen en el espacio en forma aleatoria o si existen grupos de especies con patrones de distribución comunes. En el presente estudio determinamos a través de técnicas cuantitativas si existen corotipos, es deci [...] r, grupos de especies con patrones de distribución común entre los árboles y arbustos en la zona de transición climática mediterráneo-templada de Chile, Octava Región de Chile. Adicionalmente, evaluamos la relación entre el clima y la distribución de los diferentes grupos de árboles y arbustos de la Octava Región. El análisis de agrupamiento de especies permitió definir 24 corotipos significativos, de los cuales 18 responden significativamente con alguna variable ambiental analizada. La temperatura media anual, la temperatura media invernal y la temperatura media de verano resultaron ser las variables que mejor explican el patrón de distribución de la mayoría de los corotipos. Las tendencias geográficas de los corotipos y su relación con las variables ambientales fueron evaluadas mediante un análisis de ordenación. Los resultados señalan que los corotipos con distribución en la cordillera de los Andes se correlacionan con la temperatura de invierno en tanto que los corotipos con distribución costera se correlacionan con la mediterraneidad. Se discute respecto de la utilización de una nueva aproximación para el análisis fitogeográfico y de su utilidad en el estudio de la relación entre la vegetación y los factores ambientales que determinan su distribución Abstract in english One main aim of biogeography is to determine if species are randomly distributed or if there exist groups of species with common distributional patterns known as chorotypes. In this study, we determined through quantitative techniques if there exists such chorotypes for trees and shrubs in the trans [...] itional Mediterranean-temperate climatic zone of Chile, Eigth Administrative Region of Chile. Additionally, we evaluated the relationship between climate and distribution of the different chorotypes. The analyses allowed defining 24 significant chorotypes, 18 of which were significantly associated with some used environmental variable. Mean annual temperature, mean summer temperature and mean winter temperature were the variables that explained the distribution of most of the chorotypes. The geographic tendencies of chorotypes and their relationship with environmental variables were evaluated with canonical correspondence analysis. The results indicated that chorotypes distributed in the Andes Range were correlated with the mean winter temperature, whereas chorotypes with coastal distribution were correlated with mediterreanity. We discusses the use of new approaches for phytogeographic analysis and its utility in the study of the relationship between vegetation and environmental factors that determine its distribution

  1. Temporal dynamics of soil organic carbon after land-use change in the temperate zone – carbon response functions as a model approach

    DEFF Research Database (Denmark)

    Poeplau, Christopher; Don, Axel

    2011-01-01

    Land-use change (LUC) is a major driving factor for the balance of soil organic carbon (SOC) stocks and the global carbon cycle. The temporal dynamic of SOC after LUC is especially important in temperate systems with a long reaction time. On the basis of 95 compiled studies covering 322 sites in the temperate zone, carbon response functions (CRFs) were derived to model the temporal dynamic of SOC after five different LUC types (mean soil depth of 30±6 cm). Grassland establishment caused a long lasting carbon sink with a relative stock change of 128±23% and afforestation on former cropland a sink of 116±54%, 100 years after LUC (mean±95% confidence interval). No new equilibrium was reached within 120 years. In contrast, there was no SOC sink following afforestation of grasslands and 75% of all observations showed SOC losses, even after 100 years. Only in the forest floor, there was carbon accumulation of 0.38±0.04 Mg ha-1 yr-1 in afforestations adding up to 38±4 Mg ha-1 labile carbon after 100 years. Carbon loss after deforestation (-32±20%) and grassland conversion to cropland (-36±5%), was rapid with a new SOC equilibrium being reached after 23 and 17 years, respectively. The change rate of SOC increased with temperature and precipitation but decreased with soil depth and clay content. Subsoil SOC changes followed the trend of the topsoil SOC changes but were smaller (25±5% of the total SOC changes) and with a high uncertainty due to a limited number of datasets. As a simple and robust model approach, the developed CRFs provide an easily applicable tool to estimate SOC stock changes after LUC to improve greenhouse gas reporting in the framework of UNFCCC.

  2. Uptake of and follow-up supply with [benzene ring-U-14C]triademinol via the caryopsis and from dressed zones after seed treatment of winter barley and winter wheat using a dry dressing formula

    International Nuclear Information System (INIS)

    The paper on hand studies the following issues: 1) What is the course of uptake of the agent and/or its metabolites into the plant following dry seed treatment of winter barley and winter wheat with [benzene ring-U-14C] triadimenol and sowing in the top-soil of a loess-based grey-brown podzolic soil. 2) What is the relevance of uptake and follow-up supply from the dressed zones of plants in neighbouring rows. 3) What is the extent of uptake and follow-up supply via the roots from dressed zones of neighbouring plants within the same row. 4) What is the course of dressed-zone formation following dry treatment of winter barley and winter wheat and sowing in the top-soil of a loess-based grey-brown podzolic soil. 5) What is the quantitative distribution of the agent on the pericarp of winter wheat caryopses following dry seed treatment. 6) Will the 14C-labelled agent be taken up, too, via the caryopsis and be translocated in scion and root. 7) What are the pathways of the agent from the caryopsis into the embryo. 8) How long will follow-up supply via the scutellum continue. The results concerning issues 1 to 4 were taken from tests with field lysimeters. Experiments concerning issues 6-8 were performed without soil in an climatic chamber. (orig./MG)

  3. Temperate grasslands.

    Czech Academy of Sciences Publication Activity Database

    Alba, Christina

    Ipswich : Salem Press - EBSCO Publishing, 2013 - (Howarth, R.), s. 182-187 ISBN 978-1-4298-3813-9 Institutional support: RVO:67985939 Keywords : grassland * temperate biome * ecology Subject RIV: EF - Botanics

  4. Patterns of tree seedling mortality in a temperate-mediterranean transition zone forest in Chile Patrones en la mortalidad de plántulas de especies arbóreas de un bosque de la transición templado-mediterránea de Chile

    OpenAIRE

    TERESA PARADA; Christopher H Lusk

    2011-01-01

    Seedling mortality in forests is the net result of an array of processes that vary spatially and temporally. We quantified emergence and mortality of seedlings at monthly intervals for two years, in a forest situated in the transition zone between the Mediterranean and temperate regions of Chile. We aimed to determine if survival of species responded differentially to seasonal water availability, to the spatial variation in light availability and to seedling density. The commonest species in ...

  5. Determinação por cromatografia gasosa de açúcares em frutíferas de clima temperado Gas chromatography determination of sugars in temperate-zone fruit trees

    Directory of Open Access Journals (Sweden)

    Alexandre Couto Rodrigues

    2005-04-01

    Full Text Available As frutíferas de clima temperado apresentam o fenômeno da dormência. Na saída da dormência, há a conversão do amido para açúcares solúveis, como substrato para a retomada de crescimento na primavera. Visando à maior compreensão da fisiologia das plantas em respostas a eventos, como as variações climáticas, estresses e problemas de adaptação, desenvolveu-se este trabalho, no Laboratório de Fisiologia Vegetal da Embrapa Clima Temperado, com o objetivo de descrever uma metodologia para a determinação das concentrações dos açúcares solúveis (frutose, sorbitol, alfa-glicose, beta-glicose e sacarose, em tecidos vegetais de frutíferas, via cromatografia gasosa. O cromatógrafo utilizado para as análises dos açúcares por essa metodologia é o GAS CHROMATOGRAPH e a coluna do tipo Packed Column J. K. de 3,2mm de diâmetro por 2m de comprimento, empacotada com Silicone SE-52 Uniport HP 80/100 mesh. Através da cromatografia gasosa, obtêm-se eficiência e resolução cromatográfica, para análises de açúcares solúveis, sendo, desta forma, vantajoso e executável esse tipo de análise pelo método descrito.The temperate-zone deciduous fruit trees present the phenomenon of dormancy. In that period, there is the conversion of the starch in soluble sugars, as substratum for the resumption of growth in the spring. Seeking to better understanding the physiology of the plants in answers to events as the climatic variations, stresses and adaptation problems, this study was done in the Laboratory of Crop Physiology of Embrapa Temperate Climate, with the objective of describing a methodology for determination of concentrations of the soluble sugars (fructose, sorbitol, alpha-glucose, beta-glucose and sucrose, in tissues of fruit tree, through gaseous chromatography. The chromatograph used for the analyses of the sugars was the GAS CHROMATOGRAPH with the column of the type Packed Column J. K. of 3,2mm of diameter for 2m of length packed with Silicon IF-52 Uniport HP 80/100 mesh. Through the gaseous chromatography it is obtained efficiency and chromatographic resolution to soluble sugars determination, being this way, advantageous to use this methodology.

  6. Determinação por cromatografia gasosa de açúcares em frutíferas de clima temperado / Gas chromatography determination of sugars in temperate-zone fruit trees

    Scientific Electronic Library Online (English)

    Alexandre Couto, Rodrigues; Flávio Gilberto, Herter; Valtair, Veríssimo; Geraldo, Chavarria; João Peterson Pereira, Gardin; Ângela Diniz, Campos.

    2005-04-01

    Full Text Available As frutíferas de clima temperado apresentam o fenômeno da dormência. Na saída da dormência, há a conversão do amido para açúcares solúveis, como substrato para a retomada de crescimento na primavera. Visando à maior compreensão da fisiologia das plantas em respostas a eventos, como as variações clim [...] áticas, estresses e problemas de adaptação, desenvolveu-se este trabalho, no Laboratório de Fisiologia Vegetal da Embrapa Clima Temperado, com o objetivo de descrever uma metodologia para a determinação das concentrações dos açúcares solúveis (frutose, sorbitol, alfa-glicose, beta-glicose e sacarose), em tecidos vegetais de frutíferas, via cromatografia gasosa. O cromatógrafo utilizado para as análises dos açúcares por essa metodologia é o GAS CHROMATOGRAPH e a coluna do tipo Packed Column J. K. de 3,2mm de diâmetro por 2m de comprimento, empacotada com Silicone SE-52 Uniport HP 80/100 mesh. Através da cromatografia gasosa, obtêm-se eficiência e resolução cromatográfica, para análises de açúcares solúveis, sendo, desta forma, vantajoso e executável esse tipo de análise pelo método descrito. Abstract in english The temperate-zone deciduous fruit trees present the phenomenon of dormancy. In that period, there is the conversion of the starch in soluble sugars, as substratum for the resumption of growth in the spring. Seeking to better understanding the physiology of the plants in answers to events as the cli [...] matic variations, stresses and adaptation problems, this study was done in the Laboratory of Crop Physiology of Embrapa Temperate Climate, with the objective of describing a methodology for determination of concentrations of the soluble sugars (fructose, sorbitol, alpha-glucose, beta-glucose and sucrose), in tissues of fruit tree, through gaseous chromatography. The chromatograph used for the analyses of the sugars was the GAS CHROMATOGRAPH with the column of the type Packed Column J. K. of 3,2mm of diameter for 2m of length packed with Silicon IF-52 Uniport HP 80/100 mesh. Through the gaseous chromatography it is obtained efficiency and chromatographic resolution to soluble sugars determination, being this way, advantageous to use this methodology.

  7. Evaluation on energy and thermal performance for residential envelopes in hot summer and cold winter zone of China

    International Nuclear Information System (INIS)

    As a result of rapid economic growth in the last several decades, energy issue is becoming more and more important in today's world because of a possible energy shortage in the future; the usage of residential electricity has increased rapidly in China and building energy efficiency is included as one of the 10 key programs targeting energy efficiency improvement in the 11th Five-Year Plan. In response to the growing concerns about energy conservation in residential buildings and its implications for the environment, systematic evaluation on energy and thermal Performance for residential envelops (EETP) is put forward to assess the energy efficiency of envelop designs and to calculate the energy consumption of cooling and heating systems. Hot summer and cold winter zone of China was selected for EETP analysis because of its rigorous climatic and huge energy consumption. The correlations between EETPs and electricity consumptions in cooling season, heating season, and the whole year were built in Shanghai, Changsha, Shaoguan and Chengdu, which represent A, B, C and D subzone of hot summer and cold winter zone in China, respectively. Illustrations indicate that the algorithm is simple and effective, energy and thermal performance of residential envelopes can be evaluated easily. The maximum allowable values of EETPs were determined when just meeting the compulsory indices of Standard JGJ134-2001, the corresponding allowable EETPs were also gained when achieving differens were also gained when achieving different energy-saving degrees on basis of it. EETP method can suggest possible ways to improve the energy efficiency for envelope designs of new building and retrofits of existing buildings and provide governments some useful information for the establishment of new policy on energy efficiency buildings. It has important meanings to carry out sustainable residential building designs with high thermal comfort and low energy consumption.

  8. COMPARATIVE ESTIMATION OF THE VARIETIES OF WINTER WHEAT TO AUSTRIAN SELECTION IN CONDITION OF THE CENTRAL ZONE OF THE KRASNODAR REGION ????????????? ?????? ?????? ?????? ??????? ??????????? ???????? ? ???????? ??????????? ???? ?????????????? ????

    Directory of Open Access Journals (Sweden)

    Repko N. V.

    2013-09-01

    Full Text Available The article presents the data on testing of varieties of the Austrian selection in the conditions of the central zone of the Krasnodar region. Phenological observations, winter hardiness and productivity analyzed. The influences of the seeding rate on productivity of the varieties have been discussed

  9. The importance of riparian zones on stream carbon and nitrogen export in a temperate, agricultural dominated landscape

    Directory of Open Access Journals (Sweden)

    T. Wohlfart

    2012-06-01

    Full Text Available The surrounding landscape of a stream has crucial impacts on the aquatic environment. This study pictures the hydro-biogeochemical situation of the Tyrebaekken creek catchment in central Jutland, Denmark. The intensively managed agricultural landscape is dominated by rotational croplands. One northern and one southern stream run through the catchment before converging to form a second order brook. The small catchments mainly consist of sandy soil types besides organic soils along the riparian zone of the streams. The aim of the study was to characterise the relative influence of soil type and land use on stream water quality. Nine snapshot sampling campaigns were undertaken during the growing season of 2009. On each sampling day, 20 points along the stream were sampled as well as eight drain outlets and two groundwater wells. Total dissolved nitrogen, nitrate, ammonium nitrogen and dissolved organic carbon (DOC concentrations were measured and dissolved organic nitrogen (DON was calculated for each grabbed sample. Electro-conductivity, pH and flow velocity were measured during sampling.

    Statistical analyses showed significant differences between the northern, southern and converged stream parts, especially for nitrate concentrations with average values of 9.6 mg N l?1, 1.4 mg N l?1 and 3.0 mg N l?1, respectively. Furthermore, throughout the sampling period DON concentrations increased from 0.1 mg N l?1 to 2.8 mg N l?1 and from 0.1 mg N l?1 to 0.8 mg N l?1in the northern and southern streams, respectively. This corresponded to a contribution of up to 81% to total dissolved nitrogen. Multiple-linear regression analyses performed between chemical data and landscape charateristics showed a significant negative influence of organic soils on instream N concentrations and corresponding losses in spite of their overall minor share of the agricultural land (12.9%. On the other hand, organic soil frequency was positively correlated to the corresponding dissolved organic carbon concentrations. Croplands also had a significant influence but with weaker correlations. For our case study we conclude that soil types and corresponding biogeochemical properties have a major influence on stream water chemistry. Meanwhile, the contribution of dissolved organic nitrogen to the total nitrogen budget was substantial in this agricultural dominated landscape.

  10. The importance of riparian zones on stream carbon and nitrogen export in a temperate, agricultural dominated landscape

    DEFF Research Database (Denmark)

    Wohlfart, T; Exbrayat, J F

    2012-01-01

    The surrounding landscape of a stream has crucial impacts on the aquatic environment. This study pictures the hydro-biogeochemical situation of the Tyrebaekken creek catchment in central Jutland, Denmark. The intensively managed agricultural landscape is dominated by rotational croplands. One northern and one southern stream run through the catchment before converging to form a second order brook. The small catchments mainly consist of sandy soil types besides organic soils along the riparian zone of the streams. The aim of the study was to characterise the relative influence of soil type and land use on stream water quality. Nine snapshot sampling campaigns were undertaken during the growing season of 2009. On each sampling day, 20 points along the stream were sampled as well as eight drain outlets and two groundwater wells. Total dissolved nitrogen, nitrate, ammonium nitrogen and dissolved organic carbon (DOC) concentrations were measured and dissolved organic nitrogen (DON) was calculated for each grabbed sample. Electro-conductivity, pH and flow velocity were measured during sampling. Statistical analyses showed significant differences between the northern, southern and converged stream parts, especially for nitrate concentrations with average values of 9.6mgNl?1, 1.4mgNl?1 and 3.0mgNl?1, respectively. Furthermore, throughout the sampling period DON concentrations increased from 0.1mgNl?1 to 2.8mgNl?1 and from 0.1mgNl?1 to 0.8mgNl?1 in the northern and southern streams, respectively. This corresponded to a contribution of up to 81% to total dissolved nitrogen. Multiplelinear regression analyses performed between chemical data and landscape charateristics showed a significant negative influence of organic soils on instream N concentrations and corresponding losses in spite of their overall minor share of the agricultural land (12.9%). On the other hand, organic soil frequency was positively correlated to the corresponding dissolved organic carbon concentrations. Croplands also had a significant influence but with weaker correlations. For our case study we conclude that soil types and corresponding biogeochemical properties have a major influence on stream water chemistry. Meanwhile, the contribution of dissolved organic nitrogen to the total nitrogen budget was substantial in this agricultural dominated landscape.

  11. Weed infestation of crops in different soils in the protective zone of Roztocze National Park. Part I. Winter and spring cereals

    Directory of Open Access Journals (Sweden)

    Marta Ziemi?ska-Smyk

    2004-12-01

    Full Text Available The study on weed infestation of crops in different soils in the protective zone of RPN was conducted in the years 1991-1995. The characterization of weed infestation of winter and spring cereals was based on 306 phytosociological records. made with the use of Braun-Blanquet method. The degree of weed infestation in the fields in the protective zone of RPN depended on environment conditions. Both winter and spring cereals in majority of soils were most infested by: Cenaturea cyanus, Apera spica-venti and Vicia hirsta. In the lightest podsolic soils, made of loose sand and slightly loamy sand. winter and spring cereals were additionally infested by Equisetum arvense and two acidophylic species: Seleranthus annuus and Spergula arvensis. The crops in brown loess soil were infested by Matricaria maritima subsp. inodora. The most difficult weed species in brown soil formed from gaizes and limestone soil were: Convolvulus arvensis, Papaver rhoeas and Galium aparine. Moreover winter cercals in limestone soil showed high or medium infestation with Consolida regalis, Aethusa cynapium, Lathyrus tuberosus and low infestation with Apera spica-venti and Centaurea cyanus. Spring cereals were less infested than winter cereals. Apera spica-venti and Centaurea cyanus were less common with spring cereals than with winter cereals. Also, spring cereals showed high or medium infestation with Convolvulus arvensis. Spring cereals in some soil units were infested by Chenopodium album and Stellaria media. There was also higher infestation of spring cereals in limestone soils with Avena fatua, Veronica persica, Sinapis arvensis and Sonchus arvensis, compared to winter cereals in limestone soils.

  12. Induction of photosynthesis and importance of limitations during the induction phase in sun and shade leaves of five ecologically contrasting tree species from the temperate zone.

    Science.gov (United States)

    Urban, Otmar; Kosvancová, Martina; Marek, Michal V; Lichtenthaler, Hartmut K

    2007-08-01

    We examined the principal differences in photosynthetic characteristics between sun and shade foliage and determined the relative importance of biochemical and stomatal limitations during photosynthetic induction. Temperate-zone broadleaf and conifer tree species, ranging widely in shade tolerance, were investigated from one locality in the Czech Republic. The study species included strongly shade-tolerant Abies alba Mill. and Tilia cordata Mill., less shade-tolerant Fagus sylvatica L. and Acer pseudoplatanus L. and sun-demanding Picea abies (L.) Karst. In the fully activated photosynthetic state, sun foliage of all species had significantly higher maximum CO(2) assimilation rates, maximum stomatal conductance and maximum rates of carboxylation than shade foliage. Compared with shade leaves, sun leaves had significantly higher nocturnal stomatal conductances. In all species, shade foliage tended to have higher induction states 60 s after leaf illumination than sun foliage. Sun and shade foliage did not differ in the rate of disappearance of the transient biochemical limitation during the induction phase. Longer time periods were required to reach 90% photosynthetic induction and 90% stomatal induction in sun foliage than in shade foliage of the less shade-tolerant F. sylvatica and A. pseudoplatanus and in sun-demanding P. abies; however, in sun foliage of the strongly shade-tolerant species T. cordata and A. alba, the time needed for photosynthetic induction was similar to, or less than, that for shade foliage. Shade but not sun needles of P. abies and A. alba had significantly slower induction kinetics than the broadleaf tree species. Among species, the sun-demanding P. abies exhibited the shortest stomatal induction times in both sun and shade leaves. Independently of shade tolerance ranking, the transient stomatal and total limitations that characterize photosynthetic induction were relieved significantly earlier in shade foliage than in sun foliage. Sun foliage generally exhibited a hyperbolic photosynthetic induction response, whereas a sigmoidal induction response was more frequent in shade foliage. The different relative proportions of transient biochemical and stomatal limitations during photosynthetic induction in sun and shade foliage indicate an essential role of stomata in photosynthetic limitation during induction, mainly in shade foliage, with a consequent influence on the shape of the photosynthetic induction curve. PMID:17472946

  13. A study of energy performance and audit of commercial mall in hot-summer/warm-winter climate zone in China

    Energy Technology Data Exchange (ETDEWEB)

    Zhisheng, Li; Jiawen, Liao; Xiaoxia, Wang [School of Civil and Transportation Engineering, Guangdong University of Technology, Guangzhou, Guangdong, 510006 (China); Lin, Yaolin [Building Energy Solutions and Technologies, Inc, San Jose Office, San Jose, CA 95134 (United States); Xuhong, Liu [School of Architecture and Urban Planning, Guangdong University of Technology, Guangzhou, Guangdong, 510643 (China)

    2013-08-15

    The building energy performance improvement of large-scale public buildings is very important to release China's energy shortage pressure. The aim of the study is to find out the building energy saving potentials of large-scale public and commercial buildings by energy audit. In this paper, the energy consumption, energy performance, and audit were carried out for a typical commercial mall, the so-called largest mall in Asia, located in a hot-summer and warm-winter climate zone. The total annual energy consumption reaches 210.01 kWh/m{sup 2}, of which lighting energy consumption accounts for 30.03 kWh/m{sup 2} and the lift and elevator energy consumption accounts for 40.46 kWh/m{sup 2}. It is by far higher than that of the average building energy consumption in the same category. However, the annual heating, ventilation, and air-conditioning (HVAC) energy consumption is only 87.19 kWh/m{sup 2} even though they run 24/7. It proves that the energy performance of the HVAC system is good. Therefore, the building energy savings potential mainly relies on reducing the excessive usage of lighting, lifts, and elevators.

  14. Potential effects of climate change on the temperate zones of North and South America Potenciales efectos del cambio climático en zonas templadas de América del Norte y del Sur

    Directory of Open Access Journals (Sweden)

    W.K. LAUENROTH

    2004-09-01

    Full Text Available Under current conditions, large areas of temperate western North America and temperate southern South America have arid to subhumid climates that make them vulnerable to changes as a result of human-induced climate change. Predictions of climate change from global circulation models with a doubling of present atmospheric levels of CO2 suggest large changes in mean annual temperature and small to no changes in mean annual precipitation and the proportion of precipitation received during the summer. Our objective here was to evaluate how predictions of climate change from global circulation models will influence climatic patterns and by inference the distribution of temperate zone ecosystems in North and South America. Calculations of annual water deficits suggest that the area affected by very dry conditions will double as a result of climate change. This expansion will take place in the vicinity of the currently dry areas. Monthly water deficit calculations suggest that approximately half of the temperate zone on each continent is affected by at least one month of deficit. Under a doubled CO2 climate, these areas would expand to cover up to 77 % of the temperate zone of North America and up to 80 % of South America. The resulting changes to the current distribution of ecosystems will likely be an expansion of deserts at the expense of grasslands in North and South America and an expansion of grasslands at the expense of deciduous and boreal forest in North America. Our analyses assumed that future climatic changes will be encompassed by the predictions of our three doubled CO2 scenarios. The most likely situation is that actual changes, if they occur, will be different from our scenarios. Therefore, our analyses should be interpreted as indications of the sensitivity of portions of the North and South American temperate zones to increases in temperature. The key conclusion from our analyses is that any increase in temperature caused by climate change will result in expansion of the driest portions of both continentsBajo condiciones actuales, extensas áreas de las zonas templadas del oeste de América del Norte y del sur de América del Sur tienen regímenes climáticos áridos a subhúmedos, que son vulnerables a cambios climáticos inducidos por actividades humanas. Predicciones obtenidas a partir de modelos de circulación global bajo una duplicación del CO2 atmosférico sugieren grandes cambios en temperatura media anual, y cambios pequeños o nulos en la precipitación media anual y la proporción de precipitación estival. Nuestro objetivo fue evaluar cómo las predicciones de cambio climático obtenidas de modelos de circulación global influirán sobre los patrones climáticos, e inferir a partir de ello la distribución de los ecosistemas de las zonas templadas de América del Norte y del Sur. Cálculos de déficit hídrico anual sugieren que, debido al cambio climático, se duplicará el área afectada por condiciones muy secas. Esta expansión ocurrirá en las cercanías de las zonas áridas actuales. Cálculos mensuales de déficit hídrico sugieren que aproximadamente la mitad de la zona templada de cada continente se ve afectada por al menos un mes de déficit. Bajo un clima con doble CO2, estas áreas se expandirían y cubrirían hasta 77 % de las áreas templadas de América del Norte y hasta 80 % de América del Sur. Los cambios en la distribución de ecosistemas resultantes probablemente serán debidos a la expansión de los desiertos a expensas de los pastizales en América del Norte y del Sur, y la expansión de los pastizales a expensas de los bosques deciduos y boreales en América del Norte. Nuestros análisis asumen que los cambios climáticos futuros estarán abarcados por las predicciones de los tres escenarios de duplicación de CO2 que utilizamos. La situación más probable es que los cambios reales, si es que ocurren, serán distintos a nuestros escenarios. Por lo tanto, nuestros análisis deberán interpretarse como indicaciones de la sensibilidad de partes de las zonas

  15. Tempered fractional calculus

    Science.gov (United States)

    Sabzikar, Farzad; Meerschaert, Mark M.; Chen, Jinghua

    2015-07-01

    Fractional derivatives and integrals are convolutions with a power law. Multiplying by an exponential factor leads to tempered fractional derivatives and integrals. Tempered fractional diffusion equations, where the usual second derivative in space is replaced by a tempered fractional derivative, govern the limits of random walk models with an exponentially tempered power law jump distribution. The limiting tempered stable probability densities exhibit semi-heavy tails, which are commonly observed in finance. Tempered power law waiting times lead to tempered fractional time derivatives, which have proven useful in geophysics. The tempered fractional derivative or integral of a Brownian motion, called a tempered fractional Brownian motion, can exhibit semi-long range dependence. The increments of this process, called tempered fractional Gaussian noise, provide a useful new stochastic model for wind speed data. A tempered fractional difference forms the basis for numerical methods to solve tempered fractional diffusion equations, and it also provides a useful new correlation model in time series.

  16. Summer Dormancy in Perennial Temperate Grasses

    OpenAIRE

    Volaire, Florence; Norton, Mark

    2006-01-01

    • Background and Aims Dormancy has been extensively studied in plants which experience severe winter conditions but much less so in perennial herbaceous plants that must survive summer drought. This paper reviews the current knowledge on summer dormancy in both native and cultivated perennial temperate grasses originating from the Mediterranean Basin, and presents a unified terminology to describe this trait.

  17. The nitrate leached below maize root zone is available for deep-rooted wheat in winter wheat-summer maize rotation in the North China Plain

    International Nuclear Information System (INIS)

    In winter wheat (Triticum aestivum L.)-summer maize (Zea mays L.) rotation system in the North China Plain, maize roots do not extend beyond 1.2 m in the vertical soil profile, but wheat roots can reach up to 2.0 m. Increases in soil nitrate content at maize harvest and significant reductions after winter wheat harvest were observed in the 1.4-2.0 m depth under field conditions. The recovery of 15N isotope (calcium nitrate) from various (1.0, 1.2, 1.4, 1.6, 1.8 and 2.0 m) soil depths showed that deep-rooting winter wheat could use soil nitrate up to the 2.0 m depth. This accounted partially, for the reduced nitrate in the 1.4-2.0 m depth of the soil after harvest of wheat in the rotation system. - Deep-rooted wheat can recycle nitrate leached from maize root zone in winter wheat-summer maize rotation system

  18. Potential effects of climate change on the temperate zones of North and South America / Potenciales efectos del cambio climático en zonas templadas de América del Norte y del Sur

    Scientific Electronic Library Online (English)

    W.K., LAUENROTH; H.E., EPSTEIN; J.M., PARUELO; I.C., BURKE; M.R., AGUIAR; O.E., SALA.

    2004-09-01

    Full Text Available Bajo condiciones actuales, extensas áreas de las zonas templadas del oeste de América del Norte y del sur de América del Sur tienen regímenes climáticos áridos a subhúmedos, que son vulnerables a cambios climáticos inducidos por actividades humanas. Predicciones obtenidas a partir de modelos de circ [...] ulación global bajo una duplicación del CO2 atmosférico sugieren grandes cambios en temperatura media anual, y cambios pequeños o nulos en la precipitación media anual y la proporción de precipitación estival. Nuestro objetivo fue evaluar cómo las predicciones de cambio climático obtenidas de modelos de circulación global influirán sobre los patrones climáticos, e inferir a partir de ello la distribución de los ecosistemas de las zonas templadas de América del Norte y del Sur. Cálculos de déficit hídrico anual sugieren que, debido al cambio climático, se duplicará el área afectada por condiciones muy secas. Esta expansión ocurrirá en las cercanías de las zonas áridas actuales. Cálculos mensuales de déficit hídrico sugieren que aproximadamente la mitad de la zona templada de cada continente se ve afectada por al menos un mes de déficit. Bajo un clima con doble CO2, estas áreas se expandirían y cubrirían hasta 77 % de las áreas templadas de América del Norte y hasta 80 % de América del Sur. Los cambios en la distribución de ecosistemas resultantes probablemente serán debidos a la expansión de los desiertos a expensas de los pastizales en América del Norte y del Sur, y la expansión de los pastizales a expensas de los bosques deciduos y boreales en América del Norte. Nuestros análisis asumen que los cambios climáticos futuros estarán abarcados por las predicciones de los tres escenarios de duplicación de CO2 que utilizamos. La situación más probable es que los cambios reales, si es que ocurren, serán distintos a nuestros escenarios. Por lo tanto, nuestros análisis deberán interpretarse como indicaciones de la sensibilidad de partes de las zonas templadas de América del Norte y del Sur a aumentos de temperatura. La principal conclusión de nuestros análisis es que cualquier aumento de temperatura debido a cambios climáticos resultará en una expansión de las porciones más áridas de ambos continentes Abstract in english Under current conditions, large areas of temperate western North America and temperate southern South America have arid to subhumid climates that make them vulnerable to changes as a result of human-induced climate change. Predictions of climate change from global circulation models with a doubling [...] of present atmospheric levels of CO2 suggest large changes in mean annual temperature and small to no changes in mean annual precipitation and the proportion of precipitation received during the summer. Our objective here was to evaluate how predictions of climate change from global circulation models will influence climatic patterns and by inference the distribution of temperate zone ecosystems in North and South America. Calculations of annual water deficits suggest that the area affected by very dry conditions will double as a result of climate change. This expansion will take place in the vicinity of the currently dry areas. Monthly water deficit calculations suggest that approximately half of the temperate zone on each continent is affected by at least one month of deficit. Under a doubled CO2 climate, these areas would expand to cover up to 77 % of the temperate zone of North America and up to 80 % of South America. The resulting changes to the current distribution of ecosystems will likely be an expansion of deserts at the expense of grasslands in North and South America and an expansion of grasslands at the expense of deciduous and boreal forest in North America. Our analyses assumed that future climatic changes will be encompassed by the predictions of our three doubled CO2 scenarios. The most likely situation is that actual changes, if they occur, will be different from our scenarios. Therefore, our analyses should be

  19. Spatial and temporal changes in invertebrate assemblage structure from the entrance to deep-cave zone of a temperate marble cave

    Directory of Open Access Journals (Sweden)

    Benjamin W. Tobin

    2013-09-01

    Full Text Available Seasonality in surface weather results in seasonal temperature and humidity changes in caves. Ecological and physiological differences among trogloxenes, troglophiles, and troglobionts result in species-dependent responses to this variability. To investigate these responses, we conducted five biological inventories in a marble cave in the Sierra Nevada Range, California, USA between May and December 2010. The cave was divided into six quadrats and temperature was continuously logged in each (humidity was logged at the entrance and in the deep cave. With increasing distance from the entrance, temperature changes were increasingly attenuated and lagged relative to surface temperature. Linear regressions were created to determine the relationship between measured environmental variables and diversity for cavernicoles (troglobionts and troglophiles and trogloxenes cave– wide and in the transition zone. Diversity for cavernicoles and trogloxenes peaked in the entrance and deep cave zones, respectively. Quadrat, date, 2-week antecedent temperature average, 2-week antecedent temperature range, and trogloxene abundance explained 76% of cavernicole diversity variability. Quadrat explained 55% of trogloxene diversity variability. In the transition zone, trogloxene abundance explained 26% of cavernicole variability and 2-week antecedent temperature and 2-week antecedent temperature range explained 40% of trogloxene variability. In the transition zone, trogloxene diversity was inversely related to 2-week antecedent temperature average and 2-week antecedent temperature range, suggesting that species were moving into the transition zone when temperature was most stable. In a CCA of cavernicoles distribution data and environmental variables, 35% of variation in species-specific distributions was attributable to quadrat, and non-significant percentages were explained by date and environmental variables. Differences in assemblage structure among quadrats were largely due to differences between distributions of trogloxenes and cavernicoles, but responses varied among species. Differences are likely due to ecological niche width, physiological constraints, and competition.

  20. The Influence of Weather Anomalies on Mercury Cycling in the Marine Coastal Zone of the Southern Baltic—Future Perspective

    OpenAIRE

    Be?dowska, Magdalena

    2014-01-01

    Despite the decreased emission loads of mercury, historical deposits of this metal in various compartments of the environment may become an additional diffuse source in the future. Global climate change manifests itself in the temperate zone in several ways: warmer winters, shorter icing periods, increased precipitation and heightened frequency of extreme events such as strong gales and floods, all of which cause disturbances in the rate and direction of mercury biogeochemical cycling. The pr...

  1. Impact of N-input by wet deposition on N-trace gas fluxes and CH 4-oxidation in spruce forest ecosystems of the temperate zone in Europe

    Science.gov (United States)

    Butterbach-Bahl, K.; Gasche, R.; Huber, Ch; Kreutzer, K.; Papen, H.

    In an effort to elucidate the impact of N-deposition from the atmosphere on trace gas fluxes (N 2O, NO, CH 4) from soils of temperate coniferous forests, two spruce forest sites in Germany and Ireland with comparable edaphic and climatic conditions, but with pronounced differences in the amounts of N-input from the atmosphere were compared at different seasons. At the site in Germany trace gas fluxes as well as wet deposition of NH +4 and NO -3 were recorded continuously over the entire year 1994. Correlation analysis between fluxes and N-input data were performed, in order to elucidate if a direct effect between flux and N-deposition could be demonstrated. At all sampling dates N 2O fluxes at the site receiving high atmospheric N-input (Höglwald, Germany) were significantly 1.5-5 fold higher than N 2O emission rates at the site receiving low N-input by wet deposition from the atmosphere (Ballyhooly, Ireland). In contrast to the Höglwald site, at which only emission of N 2O to the atmosphere was observed, at certain periods the Ballyhooly soil functioned as a sink for atmospheric N 2O. Methane oxidation rates were significantly lower at the Höglwald site compared to the Ballyhooly site. At the Höglwald site it could be demonstrated by correlation analysis that the input of NH +4 and NO -3 by wet deposition significantly altered emissions of N 2O and NO (stimulation) and of CH 4 oxidation (reduction). The coefficient of determination was better for NH +4 than for NO -3 for all trace gases studied and was best for the relation between NO emission rates and NH +4-input.

  2. Building energy saving potential in Hot Summer and Cold Winter (HSCW) Zone, China—Influence of building energy efficiency standards and implications

    International Nuclear Information System (INIS)

    Hot Summer and Cold Winter (HSCW) region plays an important role in China's building energy conservation task due to its high consumption in recent years for both climate and social reasons. National and local building energy standards according to which the buildings are built and operated can affect the building energy consumption to a great extent. This study investigated the energy saving potential in Hot Summer and Cold Winter Zone under different level of energy efficiency standards (China local, China national, and UK standard). Chongqing was taken as an example, and the commercial energy simulation tool eQuest was applied to analyze the building end-use energy. With the existing situation as a baseline, the building energy saving for residential section could achieve 31.5% if the Chinese national standard were satisfied, and the value would further increase to 45.0% and 53.4% when the Chongqing local and UK standard were met. For public buildings, the corresponding energy saving potentials were 62.8%, 67.4% and 75.9%. Parameter sensitivity analysis was conducted. The analysis was able to provide suggestions on energy saving implementation priorities for residential and public buildings. Indications to improve building energy standards and their implementation were also discussed. - Highlights: ? Building energy efficiency standards were compared among China, UK and the US. ? Heating energy consumption takes 1/3 of that of the residential building in HSCW Zone, China. ? Building energy saving in Chongqing is 30–70% applying various building standards. ? Public and residential buildings are most sensitive to LPD and COP respectively. ? Building energy standards should be improved and implementation should be enforced

  3. Elemental contents determination in two different zones of Mexico City on the 1987-88 and 1994-95 winters

    International Nuclear Information System (INIS)

    During the 1987-1988 and 1994-1995 winters, there were taken samples of aerosols in Mexico City, in two different places, using an integral type of sampler which determines the total amount of suspended particulates; these samples were analyzed by the multi-element analysis technique called PIXE (Proton Induced X-ray Emission). One of the sites corresponds to the Alvaro Obregon area and the other to the Azcapotzalco area (a place near to the18 de Marzo Refinery). There were determined 16 elements, heavy metals, whose concentrations show differences for both sites and periods, standing out for this study the behavior of S, V and Pb. (Author)

  4. Take-off time of the first generation of the overwintering small brown planthopper, Laodelphax striatellus in the temperate zone in East Asia.

    Science.gov (United States)

    Sanada-Morimura, Sachiyo; Otuka, Akira; Matsumura, Masaya; Etoh, Tomoki; Zhu, Yeqin; Zhou, Yijun; Zhang, Gufeng

    2015-01-01

    Overseas migration of the small brown planthopper, Laodelphax striatellus (Fallén), occurs during the winter wheat harvest season in East Asia. Knowing the take-off time of emigrating L. striatellus is crucial for predicting such migrations with a simulation technique because winds, carriers of migratory insects, change continuously. Several methods were used in China and Japan from late May to early June 2012 and again in 2013 to identify the precise timing of take-off. These methods included: a tow net trap mounted to a pole at 10 m above the ground, a helicopter-towed net trap, and a canopy trap (which also had video monitoring) set over wheat plants. Laodelphax striatellus emigrated from wheat fields mainly in the early evening, before dusk. The insects also emigrated during the daytime but rarely emigrated at dawn, showing a pattern that is unlike the bimodal emigration at dusk and dawn of two other rice planthoppers, the brown planthopper, Nilaparvata lugens (Stål), and the white-backed planthopper, Sogatella furcifera (Horváth). There was no significant difference in the temporal pattern of take-off behavior between females and males of Japanese L. striatellus populations. PMID:25780936

  5. The impacts of drainage, nutrient status and management practice on the full carbon balance of grasslands on organic soils in a maritime temperate zone

    Directory of Open Access Journals (Sweden)

    F. Renou-Wilson

    2014-04-01

    Full Text Available Temperate grasslands on organic soils are diverse due to edaphic properties but also to regional management practices and this heterogeneity is reflected in the wide range of greenhouse gas flux values reported in the literature. In Ireland, most grasslands on organic soils were drained several decades ago and are managed as extensive pastures with little or no fertilisation. This study describes a two-year study of the net ecosystem carbon balance (NECB of two such sites. We determined greenhouse gas (GHG fluxes and waterborne carbon emissions in a nutrient rich grassland and compared it with values measured from two nutrient poor organic soils: a deep drained and a shallow drained site. GHG fluxes (CO2, CH4 and N2O were determined using the chamber technique, and fluvial C fluxes were estimated by combining drainage water concentrations and flows. The nutrient rich site was an annual source of CO2 (NEE 233 g C m?2yr?1, CH4 neutral, and a small source of nitrous oxide (1.6 kg N2O-N ha?1yr?1. NEE at the shallow drained site was ?89 and ?99 g C m?2yr?1 in Years 1 and 2 respectively, and NEE at the deep drained site was +85 and ?26 g C m?2yr?1 respectively. Low CH4 emissions (1.3 g C m?2yr?1 were recorded at the shallow drained nutrient poor site. Fluvial exports from the nutrient rich site totalled 69.8 g C m?2yr?1 with 54% as dissolved organic C (DOC. Waterborne C losses from the nutrient poor site reflected differences in annual runoff totalling 44 g C m?2yr?1 in Year 1 and 30.8 g C m?2yr?1 in Year 2. The NECB of the nutrient rich grassland was 663 g C m?2yr?1 with biomass exports being the major component accounting for 53%. The NECB of the nutrient poor deep drained site was less than half of the nutrient rich site (2 year mean 267 g C m?2yr?1. Although NEE at the nutrient poor shallow drained site was negative in both years, high biomass export meant it was a net C source (2 year mean NECB 103 g C m?2yr?1. While the impacts of the nutrient and drainage status on NEE, biomass exports and fluvial C losses were confirmed, inter-regional differences in management practice and climate are also significant factors which impact on the overall NECB of these ecosystems. Contrary to expectation, the NECB of nutrient poor drained organic soils under grasslands is not necessarily a large C source and this has implications for Ireland's choice of national GHG inventory reporting methodologies. This study can also aid the development of strategies to deliver reduced emissions tailored to local grassland types.

  6. Potential effects of climate change on the temperate zones of North and South America Potenciales efectos del cambio climático en zonas templadas de América del Norte y del Sur

    OpenAIRE

    Lauenroth, W. K.; Epstein, H E; Paruelo, J. M.; Burke, I.C.; M.R. AGUIAR; Sala, O.E.

    2004-01-01

    Under current conditions, large areas of temperate western North America and temperate southern South America have arid to subhumid climates that make them vulnerable to changes as a result of human-induced climate change. Predictions of climate change from global circulation models with a doubling of present atmospheric levels of CO2 suggest large changes in mean annual temperature and small to no changes in mean annual precipitation and the proportion of precipitation received during the su...

  7. Where Does Bluetongue Virus Sleep in the Winter?

    OpenAIRE

    Wilson, Anthony; Darpel, Karin; Mellor, Philip Scott

    2008-01-01

    Bluetongue recently spread to northern Europe for the first time. Outbreaks in temperate regions are often interrupted by cold weather, but may reappear months later. Where, then, might bluetongue virus sleep in the winter?

  8. Patterns of tree seedling mortality in a temperate-mediterranean transition zone forest in Chile Patrones en la mortalidad de plántulas de especies arbóreas de un bosque de la transición templado-mediterránea de Chile

    Directory of Open Access Journals (Sweden)

    TERESA PARADA

    2011-01-01

    Full Text Available Seedling mortality in forests is the net result of an array of processes that vary spatially and temporally. We quantified emergence and mortality of seedlings at monthly intervals for two years, in a forest situated in the transition zone between the Mediterranean and temperate regions of Chile. We aimed to determine if survival of species responded differentially to seasonal water availability, to the spatial variation in light availability and to seedling density. The commonest species in the seedling bank were the Mediterranean-climate species Cryptocarya alba (61% and the temperate-climate species Aextoxicon punctatum (29%. 279 of the 504 new seedlings that emerged during the two-year study died during the same period, corresponding to 55,4% mortality. Four of the less common species (Persea lingue, Peumus boldus, Nothofagus obliqua and Luma apiculata suffered 100 % mortality of new recruits. Mortality of A. punctatum showed a marked seasonal pattern, with high mortality during the dry summer months. In contrast, mortality of the Mediterranean-climate species C. alba was more evenly distributed throughout the year. Multiple regressions showed that light availability had no significant effect on mortality of A. punctatum or C. alba. The same analysis revealed that survival of A. punctatum was negatively affected by conspecific seedling density, but this density-dependent effect was not found for C. alba. Heterospecific density-dependent effects were not found, i.e. mortality of neither species was affected by local density of seedlings of other species. This study shows that spatial and temporal variation in critical factors shapes interspecific variation in seedling mortality in this forest.La mortalidad de las plántulas es el resultado de una gama de procesos y agentes que pueden variar espacial y temporalmente en los ecosistemas forestales. En este estudio cuantificamos la emergencia y mortalidad de plántulas mes a mes, por un período de dos años en un bosque situado en la zona de transición entre la región mediterránea y templada de Chile. Pretendimos dilucidar si las especies sobreviven en forma diferencial a la disminución estacional en la disponibilidad de agua, a la variación espacial en la disponibilidad de luz y a la densidad local de plántulas. Las especies más abundantes en el banco de plántulas son la esclerófila Cryptocarya alba (61% y la especie templada Aextoxicon punctatum (29%. Del total de 504 plántulas emergidas durante el estudio, murieron 279, lo que corresponde a un 55,4 %. Cuatro de las especies menos abundantes (Persea lingue, Peumus boldus, Nothofagus obliqua y Luma apiculata sufrieron un 100 % de mortalidad de plántulas emergidas durante los dos años. La mortalidad de A.punctatum evidenció una marcada estacionalidad, con tasas elevadas durante la estación más seca (verano, pero este patrón fue mucho menos evidente en C. alba. Un análisis de regresión múltiple mostró que la luz no afectó la mortalidad de A. punctatum ni de C. alba. El mismo análisis demostró que existe un efecto densodependiente conespecífico sobre la mortalidad de A. punctatum, en contraste con C. alba, cuya mortalidad no fue afectada por la densidad conespecífica de plántulas. Efectos densodependientes comunitarios se descartan para ambas especies. La presente investigación muestra que los factores críticos varían espacial y temporalmente determinando diferencias interespecíficas en la supervivencia de plántulas de especies nativas en este tipo de ecosistema.

  9. Patterns of tree seedling mortality in a temperate-mediterranean transition zone forest in Chile / Patrones en la mortalidad de plántulas de especies arbóreas de un bosque de la transición templado-mediterránea de Chile

    Scientific Electronic Library Online (English)

    TERESA, PARADA; CHRISTOPHER H., LUSK.

    Full Text Available La mortalidad de las plántulas es el resultado de una gama de procesos y agentes que pueden variar espacial y temporalmente en los ecosistemas forestales. En este estudio cuantificamos la emergencia y mortalidad de plántulas mes a mes, por un período de dos años en un bosque situado en la zona de tr [...] ansición entre la región mediterránea y templada de Chile. Pretendimos dilucidar si las especies sobreviven en forma diferencial a la disminución estacional en la disponibilidad de agua, a la variación espacial en la disponibilidad de luz y a la densidad local de plántulas. Las especies más abundantes en el banco de plántulas son la esclerófila Cryptocarya alba (61%) y la especie templada Aextoxicon punctatum (29%). Del total de 504 plántulas emergidas durante el estudio, murieron 279, lo que corresponde a un 55,4 %. Cuatro de las especies menos abundantes (Persea lingue, Peumus boldus, Nothofagus obliqua y Luma apiculata) sufrieron un 100 % de mortalidad de plántulas emergidas durante los dos años. La mortalidad de A.punctatum evidenció una marcada estacionalidad, con tasas elevadas durante la estación más seca (verano), pero este patrón fue mucho menos evidente en C. alba. Un análisis de regresión múltiple mostró que la luz no afectó la mortalidad de A. punctatum ni de C. alba. El mismo análisis demostró que existe un efecto densodependiente conespecífico sobre la mortalidad de A. punctatum, en contraste con C. alba, cuya mortalidad no fue afectada por la densidad conespecífica de plántulas. Efectos densodependientes comunitarios se descartan para ambas especies. La presente investigación muestra que los factores críticos varían espacial y temporalmente determinando diferencias interespecíficas en la supervivencia de plántulas de especies nativas en este tipo de ecosistema. Abstract in english Seedling mortality in forests is the net result of an array of processes that vary spatially and temporally. We quantified emergence and mortality of seedlings at monthly intervals for two years, in a forest situated in the transition zone between the Mediterranean and temperate regions of Chile. We [...] aimed to determine if survival of species responded differentially to seasonal water availability, to the spatial variation in light availability and to seedling density. The commonest species in the seedling bank were the Mediterranean-climate species Cryptocarya alba (61%) and the temperate-climate species Aextoxicon punctatum (29%). 279 of the 504 new seedlings that emerged during the two-year study died during the same period, corresponding to 55,4% mortality. Four of the less common species (Persea lingue, Peumus boldus, Nothofagus obliqua and Luma apiculata) suffered 100 % mortality of new recruits. Mortality of A. punctatum showed a marked seasonal pattern, with high mortality during the dry summer months. In contrast, mortality of the Mediterranean-climate species C. alba was more evenly distributed throughout the year. Multiple regressions showed that light availability had no significant effect on mortality of A. punctatum or C. alba. The same analysis revealed that survival of A. punctatum was negatively affected by conspecific seedling density, but this density-dependent effect was not found for C. alba. Heterospecific density-dependent effects were not found, i.e. mortality of neither species was affected by local density of seedlings of other species. This study shows that spatial and temporal variation in critical factors shapes interspecific variation in seedling mortality in this forest.

  10. Hot wire TIG temper bead welding for nuclear repairs

    International Nuclear Information System (INIS)

    A preliminary assessment has been carried out to determine the suitability of the hot wire tungsten inert gas (TIG) welding process for the repair of thick section, ferritic steel nuclear pressure vessels. The objective has been to identify a hot wire TIG temper bead procedure, suitable for repairs without post weld heat treatment. This procedure involves depositing two weld layers with carefully selected welding parameters such that overlapping thermal cycles produce a refined and tempered heat affected zone, HAZ, microstructure. (author)

  11. Citril finches during the winter: patterns of distribution, the role of pines and implications for the conservation of the species.

    OpenAIRE

    Colomé, X.; Cabrera, J., s. XIX; J. A. López–Sáez; F. Alba–Sánchez; Senar, J.C.; Borras, A.; T. Cabrera

    2010-01-01

    The Citril finch Serinus citrinella is a Paleartic endemic species that breeds in the subalpine mountain zones of western temperate Europe. The species seems to be suffering a serious decline in its northern range, mainly in the Black Forest and the NE of the Alps. Numerous reasons have been provided for this decline, but all of them have been related to breeding habitats. Given that the species undergoes an altitu¬dinal migration and that during winter it may use very different habitats, a ...

  12. Protective coating of austenitic steel using robotized GMAW temper-bead technique

    International Nuclear Information System (INIS)

    This paper summarises experimental results obtained in a study of GMAW temper-bead on low alloyed steel with austenitic consumables. Temper-bead on low alloyed steel with austenitic consumables is mainly used for repairing operations of heavy components such as vessel reactor of nuclear power plants. Experimental work aims at showing the performance of GMAW compared to GTAW and the consequences of GMAW temper-bead on 2OMND5 heat affected zones. (authors)

  13. Low alloy tempering steel

    International Nuclear Information System (INIS)

    The invention deals with the use of a low-alloy steel in tempered state to produce articles with good tempering properties having a minimum tensile strength of 700 N/mm2 and an impact strength (DVM sample) of at least 55 joule. A steel with 0.35 to 0.6% C, 0.1 to 0.5% Si, 0.3 to 1.0% Mn, 0.1 to 0.6% Cr, 0.01 to 0.1% Nb, rest iron is suggested for the purpose which after austeniting by fast cooling and subsequent annealing is quenched and tempered. The invention is based on the fact that an addition of niobium combined with the choice of the suitable austeniting temperature, which on the one hand allows the solution of a sufficient amount of niobium but should however prevent the occurence of coarse grain, leads to strength and toughness properties which have only been achieved from higher-alloys tempering steels. According to a preferential design of the invention, a further steel is proposed which besides the above mentioned additions contains 0.08 to 0.12% V. The strength values of this steel are compared in figures with those of the higher-alloy and thus more expensive steel 30CrNiMo8. (GSC)

  14. Does outdoor work during the winter season protect against depression and mood difficulties?

    DEFF Research Database (Denmark)

    Hahn, Ina H; Grynderup, Matias

    2011-01-01

    At temperate latitudes, 1-5% of the population suffer from winter depression; during winter, mood difficulties tend to increase but may be alleviated by bright light therapy. Unlike indoor workers, outdoor workers are exposed to therapeutic levels of sunlight during winter. We hypothesized that outdoor work may protect against mood difficulties and depression.

  15. Off-season uptake of nitrogen in temperate heath vegetation

    DEFF Research Database (Denmark)

    Andresen, Louise Christoffersen; Michelsen, Anders

    2004-01-01

    Off-season ecosystem processes is becoming an area of increasing interest, being important when considering annual nitrogen and carbon budgets. The general assumption that physiological activity in soil microorganisms as well as vegetation is low during winter may not be justified. In this field study we show that northern temperate coastal heath vegetation has a significant uptake potential for nitrogen, both in the form of ammonium and as glycine, throughout the non-growing season. We used 15N ammonium and 2*(13C)15N glycine as nutrient tracer. This was injected into the soil two times during winter and once at spring. The winter temperatures were similar to those of average winter in the northern temperate region of Europe, with only few days of soil temperatures below zero and a winter mean of 2.4 °C. The vegetation, consisting of the evergreen dwarf shrub Calluna vulgaris (L.), the deciduous dwarf shrub Salix arenaria (L.) and the graminoids Carex arenaria (L.) and Deschampsia flexuosa (L.), showed root uptake of both forms of nitrogen, both one day after labelling and after a month. Translocation of the labelled nitrogen to shoots was generally evident after one month and increased as spring approached, with different translocation strategies in the three plant functional types. Furthermore, shoot total nitrogen concentration increased in all plant types, but only the graminoids and, eventually, S. arenaria showed shoot growth during winter. Our study suggests that plant nitrogen uptake can cause increasing nitrogen concentration in shoot tissue from fall to spring. To our knowledge this is one of the first studies of plant nitrogen uptake during nongrowing season at a temperate heath. Our results show that the nitrogen uptake is in the same order of magnitude as summer uptake in other types of ecosystems in the temperate/boreal region. These results suggest that plant nitrogen uptake during winter should be included in the annual nitrogen budgets of heath ecosystems, and that the view of plant nutrient uptake as low in this climatic region during winter should be revised. Furthermore, these results should be taken into account when ecosystem responses to climatic changes such as warming are evaluated.

  16. Alcohol, Temperance & Prohibition

    Science.gov (United States)

    2012-06-01

    The temperance movement in the United States gained steam in the late 19th century, and by the early 20th century, many political candidates would be asked "Are you 'dry' or 'wet?'" This single issue led to the creation of the 18th Amendment in 1919, which effectively prohibited the manufacturing, sale or transportation of intoxicating liquors. After fourteen years, the 21st Amendment was passed, and the country went back to imbibing beer and spirits (legally, anyway). This fine collection from the Brown University Library Center for Digital Scholarship brings together over 1,600 pieces of ephemera, such as broadsides and pamphlets, that document the quest to make prohibition a reality during this period in American history. First-time visitors may wish to start by reading the narrative essay titled "Temperance and Prohibition Era Propaganda: A Study in Rhetoric." Moving on, visitors can browse and search their way through this remarkable collection. Items of note include a 1913 informational handout titled "Abstainers have less sickness" and the 1928 Women's Christian Temperance Union publication "American Youth Under Prohibition."

  17. Tempering the polylogarithm

    CERN Document Server

    Epstein, C L; Epstein, Charles L.; Morava, Jack

    2006-01-01

    We show that the function Li_s(e^x) extends to an entire function of the complex variable s, taking values in tempered distributions in x on the whole real line. That the classical polylogarithm extends similarly, as an entire function taking values in distributions on compactly-supported functions on the positive real axis, is a corollary. We then identify the singularities of Li_s(e^x) in terms of distribution powers of x; this leads to a simple proof of the smoothness of the `modified' polylogarithm of Bloch, Ramakrishnan, Wigner, Wojtkowiak, Zagier, and others.

  18. Late Quaternary environmental change along the temperate-tropical interface in southern Africa. (Invited)

    Science.gov (United States)

    Chase, B. M.

    2013-12-01

    As a relatively low-relief landscape stretching from the equator to the mid-latitudes, the African sector of the Southern Hemisphere provides an excellent opportunity to study long-term interactions between tropical, subtropical and temperate climate systems. This potential, however, has remained largely unrealised as funding has generally been focussed on the large lakes of Eastern Africa and the analysis of marine cores from the continental margin. The result is a spatially and temporally disjunct regional dataset, and the dominance of broad conceptual models to contextualise the limited available data and explain palaeoenvironmental dynamics. The dominant hypotheses to explain long-term climate change in southern Africa are: 1) changes in temperate systems result from expansions and contractions of Antarctic sea-ice that vary with trends in polar/global temperatures; 2) tropical change is primarily a function of shifts in the mean position of the Intertropical Convergence Zone (ITCZ) as a result of orbitally-induced changes in direct insolation forcing, and/or as a response to Northern Hemisphere cooling. In both cases, some evidence exists to support these hypotheses, but the proxies and interpretations are not unambiguous, and in some cases the interpretations of the data have been primarily developed to conform to the dominant conceptual paradigm. This paper will discuss the interplay between temperate and tropical systems in southern Africa, and the implications for hemispheric and global climate dynamics. New data, particularly high-resolution records from fossilised rock hyrax middens (Chase et al., 2012, Quaternary Science Reviews; www.hyrax.univ-montp2.fr), is providing a robust framework into which lower resolution or more poorly understood proxies can better understood. Findings from a subcontinental-scale initiative funded by the European Research Council so far indicate that shifts of the Subtropical Front and the westerly storm tracks did bring increased moisture to SW Africa during phases of the last glacial period, and that the so-called winter rainfall zone (sensu Chase and Meadows, 2007, Earth-Science Reviews) extended at least as far north as central Namibia. It cannot, however, be said that all cold periods resulted in increased westerly influence in the region, as changes in the position and intensity of the South Atlantic Anticyclone have at times modified their impact. New evidence also clearly indicates that shifts in the mean position of the ITCZ, either as a result of direct insolation forcing or Northern Hemisphere cooling, did not determine patterns of long-term climate change in southern Africa, and that both the northern and southern tropics experienced synchronous patterns of climate change since the Last Glacial Maximum (Chase et al., 2009, Geology; Truc et al., 2013, Palaeogeography, Palaeoclimatology, Palaeoecology).

  19. Carbon sinks in temperate forests

    OpenAIRE

    Martin, P.H.; Nabuurs, G.J.; M. Aubinet; Karjalainen, T.; Vine, E.L.; Kinsman, J; Heath, L.S.

    2001-01-01

    In addition to being scientifically exciting, commercially important, and environmentally essential, temperate forests have also become a key diplomatic item in international climate negotiations as potential sinks for carbon. This review presents the methods used to estimate carbon sequestration, identifies the constraints and opportunities for carbon sequestration in temperate forests, addresses the issues raised by the monitoring of carbon sequestration, and analyzes uncertainties pertaini...

  20. Comparison of Seasonal Soil Microbial Process in Snow-Covered Temperate Ecosystems of Northern China

    OpenAIRE

    Zhang, Xinyue; Wang, Wei; Chen, Weile; Zhang, Naili; Zeng, Hui

    2014-01-01

    More than half of the earth's terrestrial surface currently experiences seasonal snow cover and soil frost. Winter compositional and functional investigations in soil microbial community are frequently conducted in alpine tundra and boreal forest ecosystems. However, little information on winter microbial biogeochemistry is known from seasonally snow-covered temperate ecosystems. As decomposer microbes may differ in their ability/strategy to efficiently use soil organic carbon (SOC) within di...

  1. Winter Weather

    Science.gov (United States)

    ... Regulations Enforcement Data & Statistics Training Publications Newsroom Small Business Anti-Retaliation Home Workers Regulations Enforcement Data & Statistics Training Publications Newsroom Small Business Anti-Retaliation Winter ...

  2. Photosynthesis of temperate Eucalyptus globulus trees outside their native range has limited adjustment to elevated CO2 and climate warming.

    Science.gov (United States)

    Crous, Kristine Y; Quentin, Audrey G; Lin, Yan-Shih; Medlyn, Belinda E; Williams, David G; Barton, Craig V M; Ellsworth, David S

    2013-12-01

    Eucalyptus species are grown widely outside of their native ranges in plantations on all vegetated continents of the world. We predicted that such a plantation species would show high potential for acclimation of photosynthetic traits across a wide range of growth conditions, including elevated [CO2] and climate warming. To test this prediction, we planted temperate Eucalyptus globulus Labill. seedlings in climate-controlled chambers in the field located >700 km closer to the equator than the nearest natural occurrence of this species. Trees were grown in a complete factorial combination of elevated CO2 concentration (eC; ambient [CO2] +240 ppm) and air warming treatments (eT; ambient +3 °C) for 15 months until they reached ca. 10 m height. There was little acclimation of photosynthetic capacity to eC and hence the CO2-induced photosynthetic enhancement was large (ca. 50%) in this treatment during summer. The warming treatment significantly increased rates of both carboxylation capacity (V(cmax)) and electron transport (Jmax) (measured at a common temperature of 25 °C) during winter, but decreased them significantly by 20-30% in summer. The photosynthetic CO2 compensation point in the absence of dark respiration (?*) was relatively less sensitive to temperature in this temperate eucalypt species than for warm-season tobacco. The temperature optima for photosynthesis and Jmax significantly changed by about 6 °C between winter and summer, but without further adjustment from early to late summer. These results suggest that there is an upper limit for the photosynthetic capacity of E. globulus ssp. globulus outside its native range to acclimate to growth temperatures above 25 °C. Limitations to temperature acclimation of photosynthesis in summer may be one factor that defines climate zones where E. globulus plantation productivity can be sustained under anticipated global environmental change. PMID:23824839

  3. Simulating the Effect of Climate Change on Vegetation Zone Distribution on the Loess Plateau, Northwest China

    Directory of Open Access Journals (Sweden)

    Guoqing Li

    2015-06-01

    Full Text Available A risk assessment of vegetation zone responses to climate change was conducted using the classical Holdridge life zone model on the Loess Plateau of Northwest China. The results show that there are currently ten vegetation zones occurring on the Loess Plateau (1950–2000, including alvar desert, alpine wet tundra, alpine rain tundra, boreal moist forest, boreal wet forest, cool temperate desert, cool temperate desert scrub, cool temperate steppe, cool temperate moist forest, warm temperate desert scrub, warm temperate thorn steppe, and warm temperate dry forest. Seventy years later (2070S, the alvar desert, the alpine wet tundra and the cool temperate desert will disappear, while warm temperate desert scrub and warm temperate thorn steppe will emerge. The area proportion of warm temperate dry forest will expand from 12.2% to 22.8%–37.2%, while that of cool temperate moist forest will decrease from 18.5% to 6.9%–9.5%. The area proportion of cool temperate steppe will decrease from 51.8% to 34.5%–51.6%. Our results suggest that future climate change will be conducive to the growth and expansion of forest zones on the Loess Plateau, which can provide valuable reference information for regional vegetation restoration planning and adaptive strategies in this region.

  4. Transfer parameter values in temperate forest ecosystems: a review

    International Nuclear Information System (INIS)

    Compared to agricultural lands, forests are complex ecosystems as they can involve diverse plant species associations, several vegetative strata (overstorey, shrubs, herbaceous and other annual plant layer) and multi-layered soil profiles (forest floor, hemi-organic and mineral layers). A high degree of variability is thus generally observed in radionuclide transfers and redistribution patterns in contaminated forests. In the long term, the soil compartment represents the major reservoir of radionuclides which can give rise to long-term plant and hence food contamination. For practical reasons, the contamination of various specific forest products has commonly been quantified using the aggregated transfer factor (Tag in m2 kg-1) which integrates various environmental parameters including soil and plant type, root distribution as well as nature and vertical distribution of the deposits. Long lasting availability of some radionuclides was shown to be the source of much higher transfer in forest ecosystems than in agricultural lands. This study aimed at reviewing the most relevant quantitative information on radionuclide transfers to forest biota including trees, understorey vegetation, mushrooms, berries and game animals. For both radiocaesium and radiostrontium in trees, the order of magnitude of mean Tag values was 10-3 m2 kg-1 (dry weight). Tree foliage was usually 2-12 times more contaminatage was usually 2-12 times more contaminated than trunk wood. Maximum contamination of tree components with radiocaesium was associated with (semi-)hydromorphic areas with thick humus layers. The transfer of radionuclides to mushrooms and berries is high, in comparison with foodstuffs grown in agricultural systems. Concerning caesium uptake by mushrooms, the transfer is characterized by a very large variability of Tag, from 10-3 to 101 m2 kg-1 (dry weight). For berries, typical values are around 0.01-0.1 m2 kg-1 (dry weight). Transfer of radioactive caesium to game animals and reindeer and the rate of activity reduction, quantified as an ecological half-life, reflect the soil and pasture conditions at individual locations. Forests in temperate and boreal regions differ with respect to soil type and vegetation, and a faster decline of muscle activity concentrations in deer occurs in the temperate zone. However, in wild boar the caesium activity concentration shows no decline because of its special feeding habits. In the late phase, i.e. at least a few months since the external radionuclide contamination on feed plants has been removed, a Tag value of 0.01 m2 kg-1 (fresh weight) is common for 137Cs in the muscles of adult moose and terrestrial birds living in boreal forests, and 0.03 m2 kg-1 (fresh weight) for arctic hare. Radiocaesium concentrations in reindeer muscle in winter may exceed the summer content by a factor of more than two, the mean Tag values for winter ranging from 0.02 to 0.8 m2 kg-1 (fresh weight), and in summer from 0.04 to 0.4 m2 kg-1. The highest values are found in the year of initial contamination, followed by a gradual reduction. In waterfowl a relatively fast decline in uptake of 137Cs has been found, with Tag values changing from 0.01 to 0.002 m2 kg-1 (fresh weight) in the three years after the contaminating event, the rate being determined by the dynamics of 137Cs in aquatic ecosystems.

  5. Fruiting and flushing phenology in Asian tropical and temperate forests: implications for primate ecology.

    Science.gov (United States)

    Hanya, Goro; Tsuji, Yamato; Grueter, Cyril C

    2013-04-01

    In order to understand the ecological adaptations of primates to survive in temperate forests, we need to know the general patterns of plant phenology in temperate and tropical forests. Comparative analyses have been employed to investigate general trends in the seasonality and abundance of fruit and young leaves in tropical and temperate forests. Previous studies have shown that (1) fruit fall biomass in temperate forest is lower than in tropical forest, (2) non-fleshy species, in particular acorns, comprise the majority of the fruit biomass in temperate forest, (3) the duration of the fruiting season is shorter in temperate forest, and (4) the fruiting peak occurs in autumn in most temperate forests. Through our comparative analyses of the fruiting and flushing phenology between Asian temperate and tropical forests, we revealed that (1) fruiting is more annually periodic (the pattern in one year is similar to that seen in the next year) in temperate forest in terms of the number of fruiting species or trees, (2) there is no consistent difference in interannual variations in fruiting between temperate and tropical forests, although some oak-dominated temperate forests exhibit extremely large interannual variations in fruiting, (3) the timing of the flushing peak is predictable (in spring and early summer), and (4) the duration of the flushing season is shorter. The flushing season in temperate forests (17-28 % of that in tropical forests) was quite limited, even compared to the fruiting season (68 %). These results imply that temperate primates need to survive a long period of scarcity of young leaves and fruits, but the timing is predictable. Therefore, a dependence on low-quality foods, such as mature leaves, buds, bark, and lichens, would be indispensable for temperate primates. Due to the high predictability of the timing of fruiting and flushing in temperate forests, fat accumulation during the fruit-abundant period and fat metabolization during the subsequent fruit-scarce period can be an effective strategy to survive the lean period (winter). PMID:23354470

  6. Candidate gene association mapping for winter survival and spring regrowth in perennial ryegrass.

    Science.gov (United States)

    Yu, Xiaoqing; Pijut, Paula M; Byrne, Stephen; Asp, Torben; Bai, Guihua; Jiang, Yiwei

    2015-06-01

    Perennial ryegrass (Lolium perenne L.) is a widely cultivated cool-season grass species because of its high quality for forage and turf. Susceptibility to freezing damage limits its further use in temperate zones. The objective of this study was to identify candidate genes significantly associated with winter survival and spring regrowth in a global collection of 192 perennial ryegrass accessions. Significant differences in winter survival (WS), percentage of canopy green cover (CGC), chlorophyll index (Chl), and normalized difference vegetation index (NDVI) were found among accessions. After controlling population structure, LpLEA3 encoding a late embryogenesis abundant group 3 protein and LpCAT encoding a catalase were associated with CGC and Chl, while LpMnSOD encoding a magnesium superoxide dismutase and LpChl Cu-ZnSOD encoding a chlorophyll copper-zinc superoxide dismutase were associated with NDVI or Chl. Significant association was also discovered between C-repeat binding factor LpCBF1b and WS. Three sequence variations identified in LpCAT, LpMnSOD, and LpChl Cu-ZnSOD were synonymous substitutions, whereas one pair of adjacent single nucleotide polymorphisms (SNPs) in LpLEA3 and one SNP in LpCBF1b resulted in amino acid change. The results demonstrated that allelic variation in LpLEA3 and LpCBF1b was closely related to winter survival and spring regrowth in perennial ryegrass. PMID:25900564

  7. Seasonal variability of methane ebullition in a temperate freshwater reservoir

    Science.gov (United States)

    Frouzova, Jaroslava; Tuser, Michal; Stanovsky, Petr; Picek, Tomas

    2015-04-01

    Seasonal variability of methane ebullition was observed in the temperate freshwater reservoir of ?ímov (Czech Republic) in 2014. The canyon-shaped reservoir with one main tributary covers 210 ha with a maximum depth of 40 m and serves as drinking water supply. The whole area of open water of the reservoir was acoustically investigated fortnightly all year round, except periods with ice cover. Anchored submerged funnels were then placed in ebullitive zones of the reservoir (the upper part) covering a depth range of 4 - 12 m. Sampled gas bubbles were analyzed using gas chromatography. Methane concentration in the sampled bubbles varied from 0 to 82 %. The main ebullition peak occurred in the beginning of July, reaching values up to 1200 mg of CH4 per square meter per day. These values support the assumption that reservoirs in the temperate zone are not negligible sources of methane.

  8. The Effects of Additive Feeding and Feed Additives Before Wintering on Honey Bee Colony Performances, Wintering Abilities and Survival Rates at the East Mediterranean Region

    Directory of Open Access Journals (Sweden)

    Ethem Akyol

    2006-01-01

    Full Text Available In this study; the effects of additive feeding with vitamin, fumagillin and pollen supplement on survival rates, wintering abilities, amount of adult bees and brood production were examined at subtropical temperate region before wintering. The wintering ability, survival rates, adult bees and brood areas were positively affected by feeding and feed additives. The lowest values of research components were observed on unfed control groups colonies.

  9. The Effects of Additive Feeding and Feed Additives Before Wintering on Honey Bee Colony Performances, Wintering Abilities and Survival Rates at the East Mediterranean Region

    OpenAIRE

    Ethem Akyol; Halil Yeninar; Nuray Sahinler; Ahmet Guler

    2006-01-01

    In this study; the effects of additive feeding with vitamin, fumagillin and pollen supplement on survival rates, wintering abilities, amount of adult bees and brood production were examined at subtropical temperate region before wintering. The wintering ability, survival rates, adult bees and brood areas were positively affected by feeding and feed additives. The lowest values of research components were observed on unfed control groups colonies.

  10. Solar ventilation and tempering

    Science.gov (United States)

    Adámek, Karel; Pavlů, Miloš; Bandouch, Milan

    2014-08-01

    The paper presents basic information about solar panels, designed, realized and used for solar ventilation of rooms. Used method of numerical flow simulation gives good overview about warming and flowing of the air in several kinds of realized panels (window, facade, chimney). Yearlong measurements give a good base for calculations of economic return of invested capital. The operation of the system in transient period (spring, autumn) prolongs the period without classical heating of the room or building, in winter the classical heating is supported. In the summer period the system, furnished with chimney, can exhaust inner warm air together with necessary cooling of the system by gravity circulation, only. System needs not any invoiced energy source; it is supplied entirely by solar energy. Large building systems are supported by classical electric fan respectively.

  11. Time-temperature equivalence in Martensite tempering

    Energy Technology Data Exchange (ETDEWEB)

    Hackenberg, Robert E. [Los Alamos National Laboratory; Thomas, Grant A. [CSM; Speer, John G. [CSM; Matlock, David K. [CSM; Krauss, George [CSM

    2008-06-16

    The relationship between time and temperature is of great consequence in many materials-related processes including the tempering of martensite. In 1945, Hollomon and Jaffe quantified the 'degree of tempering' as a function of both tempering time, t, and tempering temperature, T, using the expression, T(log t + c). Here, c is thought to be a material constant and appears to decrease linearly with increasing carbon content. The Hollomon-Jaffe tempering parameter is frequently cited in the literature. This work reviews the original derivation of the tempering parameter concept, and presents the use of the characteristics diffusion distance as an alternative time-temperature relationship during martensite tempering. During the tempering of martensite, interstitial carbon atoms diffuse to form carbides. In addition, austenite decomposes, dislocations and grain boundaries rearrange, associated with iron self diffusion. Since these are all diffusional processes, it is reasonable to expect the degree of tempering to relate to the extent of diffusion.

  12. Diversity and abundance of photosynthetic sponges in temperate Western Australia

    Directory of Open Access Journals (Sweden)

    Brümmer Franz

    2009-02-01

    Full Text Available Abstract Background Photosynthetic sponges are important components of reef ecosystems around the world, but are poorly understood. It is often assumed that temperate regions have low diversity and abundance of photosynthetic sponges, but to date no studies have investigated this question. The aim of this study was to compare the percentages of photosynthetic sponges in temperate Western Australia (WA with previously published data on tropical regions, and to determine the abundance and diversity of these associations in a range of temperate environments. Results We sampled sponges on 5 m belt transects to determine the percentage of photosynthetic sponges and identified at least one representative of each group of symbionts using 16S rDNA sequencing together with microscopy techniques. Our results demonstrate that photosynthetic sponges are abundant in temperate WA, with an average of 63% of sponge individuals hosting high levels of photosynthetic symbionts and 11% with low to medium levels. These percentages of photosynthetic sponges are comparable to those found on tropical reefs and may have important implications for ecosystem function on temperate reefs in other areas of the world. A diverse range of symbionts sometimes occurred within a small geographic area, including the three "big" cyanobacterial clades, Oscillatoria spongeliae, "Candidatus Synechococcus spongiarum" and Synechocystis species, and it appears that these clades all occur in a wide range of sponges. Additionally, spongin-permeating red algae occurred in at least 7 sponge species. This study provides the first investigation of the molecular phylogeny of rhodophyte symbionts in sponges. Conclusion Photosynthetic sponges are abundant and diverse in temperate WA, with comparable percentages of photosynthetic to non-photosynthetic sponges to tropical zones. It appears that there are three common generalist clades of cyanobacterial symbionts of sponges which occur in a wide range of sponges in a wide range of environmental conditions.

  13. Linking winter and summer events in a migratory bird by using stable-carbon isotopes

    Science.gov (United States)

    Marra; Hobson; Holmes

    1998-12-01

    For migratory birds, early arrival and physical condition on the breeding grounds are important determinants of reproductive success and fitness. Differences in arrival times often exceed a month, and later arriving individuals are often in poorer condition. Habitat-specific isotopic signatures indicate that the quality of winter habitats occupied by American redstarts (Setophaga ruticilla) determines their physical condition and spring departure dates, which in turn result in variable arrival schedules and condition on temperate breeding grounds. These findings link events in tropical winter grounds with those in temperate breeding areas for a migratory songbird and provide evidence that winter habitats may be limiting. PMID:9836637

  14. Timing of eclosion affects diapause development, fat body consumption and longevity in Osmia lignaria, a univoltine, adult-wintering solitary bee

    Science.gov (United States)

    Most insects from temperate areas enter diapause ahead of winter. Species diapausing in a feeding stage and accumulating metabolic reserves during permissive pre-wintering conditions are expected to enter diapause late in relation to the onset of winter. Instead, species diapausing in a non-feeding ...

  15. Transformation and tempering behavior of 12Cr-1Mo-0.3V martensitic stainless steel weldments

    International Nuclear Information System (INIS)

    Autogeneous, bead-on-plate gas tungsten-arc (GTA) and laser welds in a 12Cr-1Mo-0.3V (HT9) martensitic stainless steel were evaluated using both optical metallography and microhardness techniques. The as-welded fusion zone microstructures consisted of a mixture of untempered martensite and metastable delta ferrite and exhibited a hardness in the range of Rsub(c) 48-55. Four distinct microstructural regions were identified in the heat-affected zone (HAZ) of the GTA welds and could be related to specific phase regions on the equilibrium phase diagram. The tempering behavior of the GTA and laser welds was similar. The tempering response was relatively sluggish at temperatures below 6000C (11100F). Tempering for 1 hour at 8000C (14700F) reduced the hardness of both the fusion zone and HAZ to the level of the quenched and tempered base metal. (orig.)

  16. Welding metallurgy of SA508 Cl II heat affected zones

    International Nuclear Information System (INIS)

    A weld thermal simulation technique has been used to investigate the metallurgical response of SA508 class II material during welding. Dynamic Ac1 and Ac3 data, grain growth kinetics and continuous cooling transformation diagrams have been measured. The heat affected zone structure, grain size and precipitate distribution are described in terms of the weld thermal cycle experienced and compared with a weld heat affected zone. The as-welded hardness and tempering response of a range of possible heat affected zone structures has been established. The tempering effects of various weld thermal cycles are calculated from isothermal tempering data. The likely tempering effects during welding are estimated and compared with the tempering of actual welds during welding and in subsequent conventional post weld heat treatment. 16 figures, 6 tables

  17. Responses of plankton and fish from temperate zones to UVR and temperature in a context of global change / Respuestas del plancton y peces de zonas templadas a la RUV y la temperatura en un contexto de cambio global

    Scientific Electronic Library Online (English)

    Rodrigo J, Gonçalves; María Sol, Souza; Juana, Aigo; Beatriz, Modenutti; Esteban, Balseiro; Virginia E, Villafañe; Víctor, Cussac; E Walter, Helbling.

    2010-08-01

    Full Text Available En las últimas décadas, tanto la temperatura como la radiación UVB (280-315 nm) en la superficie del planeta han aumentado a velocidades crecientes como resultado de las actividades humanas. Muchos estudios han evaluado ya los efectos de la temperatura en ecosistemas acuáticos, pero ahora el campo d [...] e estudio se amplía a medida que cobra importancia la combinación de dichos factores. En el presente estudio, intentamos rever una parte de lo que sabemos acerca de los efectos de la RUV y la temperatura en el plancton marino y dulceacuícola y peces de latitudes medias (definidas como aquellas comprendidas entre 30 y 60º), especialmente en la región Patagónica, debido a las características particulares de estas regiones. La RUV afecta (en general, negativamente) casi todos los procesos, desde la fijación de carbono hasta el comportamiento y ciertamente todos los niveles tróficos dentro del plancton, desde virus hasta larvas de peces. El mayor efecto negativo de la RUV es probablemente la acción mutagénica de la UVB, la cual afecta un número de procesos tales como fotosíntesis, crecimiento y división celular, entre muchos otros. En los metazoos, la RUV puede ser un factor de estrés que afecta la supervivencia, o bien puede mostrar efectos subletales tales como en el comportamiento y alimentación. Es difícil extraer un patrón general en cuanto a las respuestas, aun dentro de un grupo de organismos, ya que éstas son generalmente especie-específicas y están fuertemente influenciadas por condiciones locales (e.g., penetración de la RUV, relación PAR/RUV y aclimatación). A pesar de que en muchos casos se han determinado efectos significativos, muchos organismos también disponen de mecanismos para evitar o minimizar el daño producido por la RUV. Sin embargo, este puede no ser el caso si consideramos los cambios en la temperatura. En peces por ejemplo, la temperatura es probablemente el factor más importante que determina la distribución del hábitat, y por lo tanto la biogeografía debe ser considerada para considerar las posibles consecuencias de los cambios de temperatura y de la RUV. Aun en los diferentes escenarios predichos por los modelos climáticos (incluyendo la recuperación de la capa de ozono y el aumento de la temperatura durante las próximas décadas) serán necesarias más investigaciones combinando RUV y temperatura para entender las respuestas de los ecosistemas acuáticos en el contexto del cambio global. Abstract in english In the last decades, both temperature and UVB (280-315 nm) radiation on the surface of the Earth increased at growing rates as a result of human activities. Many studies had evaluated the effects of temperature on aquatic ecosystems, but now the field broadens as the combination and variations of te [...] mperature and radiation gains especial importance. In this work we attempt to revisit some of our knowledge about the effects of UVR and temperature on marine and freshwater plankton and fish from temperate regions (defined here as latitudes between 30-60º), especially from the Patagonia area, due to the special characteristics found in these sites. UVR affects (often negatively) almost all processes, from carbon fixation to behavior; and certainly all trophic levels in plankton, from virus to fish larvae. The most prominent UVR danger is probably the mutagenic action of UVB, which will affect a number of processes such as photosynthesis, growth and cell division, among many others. In metazoans, UVR may cause stress upon survival or show sublethal effects such as those in behavior and feeding. It is difficult to extract a general pattern, even in a group of organisms, as responses to UVR appear to be species-specific and strongly influenced by local conditions (e.g., UVR penetration, PAR/UVR ratios, and acclimation). While in many cases significant effects have been determined, a number of mechanisms are available to avoid and / or minimize the damage produced by UVR. However, this may not hold true for global temperature changes. In

  18. Elliptical Tempered Stable Distribution and Fractional Calculus

    OpenAIRE

    Fallahgoul, Hassan A.; Young S. Kim

    2014-01-01

    A definition for elliptical tempered stable distribution, based on the characteristic function, have been explained which involve a unique spectral measure. This definition provides a framework for creating a connection between infinite divisible distribution, and particularly elliptical tempered stable distribution, with fractional calculus. Finally, some analytical approximations for the probability density function of tempered infinite divisible distribution, which ellipt...

  19. Chilling and heat requirements for flowering in temperate fruit trees

    Science.gov (United States)

    Guo, Liang; Dai, Junhu; Ranjitkar, Sailesh; Yu, Haiying; Xu, Jianchu; Luedeling, Eike

    2014-08-01

    Climate change has affected the rates of chilling and heat accumulation, which are vital for flowering and production, in temperate fruit trees, but few studies have been conducted in the cold-winter climates of East Asia. To evaluate tree responses to variation in chill and heat accumulation rates, partial least squares regression was used to correlate first flowering dates of chestnut ( Castanea mollissima Blume) and jujube ( Zizyphus jujube Mill.) in Beijing, China, with daily chill and heat accumulation between 1963 and 2008. The Dynamic Model and the Growing Degree Hour Model were used to convert daily records of minimum and maximum temperature into horticulturally meaningful metrics. Regression analyses identified the chilling and forcing periods for chestnut and jujube. The forcing periods started when half the chilling requirements were fulfilled. Over the past 50 years, heat accumulation during tree dormancy increased significantly, while chill accumulation remained relatively stable for both species. Heat accumulation was the main driver of bloom timing, with effects of variation in chill accumulation negligible in Beijing's cold-winter climate. It does not seem likely that reductions in chill will have a major effect on the studied species in Beijing in the near future. Such problems are much more likely for trees grown in locations that are substantially warmer than their native habitats, such as temperate species in the subtropics and tropics.

  20. Winter Depression

    Science.gov (United States)

    A U.K. psychologist has developed a complex mathematical formula using seven variables to predict winter's emotional low point. The good news is the worst day of the year was last week; nonetheless, seasonal depression remains a problem for many. The first link (1) is to an article about the equation worked out by Dr. Cliff Arnall, who specializes in seasonal disorders at the University of Cardiff, Wales. The second link is to a WebMD page (2) about winter depression, often referred to as Seasonal Affective Disorder (SAD). The next link (3) is to a recent news story about the results of a five-year study that found, rather than antidepressant drug therapy or air ionizers, light box therapy is the best remedy for the seasonal condition. The fourth link is to a set of Frequently Asked Questions (4) about SAD offered by Columbia Presbyterian Medical Center in New York City. The fifth link, to the Winter Depression Research Group at the University of Tromso in Norway(5), explains why Norway is a natural SAD research laboratory. The next link is to a international portal site (6) maintained by medical professionals and researchers in the field of light therapy and biological rhythms. The final webpage(7), from Psychology Today, compares the symptoms of winter depression with summer depression.

  1. Winter Math

    Science.gov (United States)

    Wendy Petti

    2009-01-13

    This article by Wendy Petti presents ideas and math activities for students to explore snowflakes and winter by making estimates, by counting and by measuring. Data collection, displays and analysis ideas are also included. A list of online resources with their links provides more wintry ideas for the classroom.

  2. Distribution of mesopelagic micronekton in the Arabian Sea during the winter monsoon

    Digital Repository Service at National Institute of Oceanography (India)

    Karuppasamy, P.K.; Muraleedharan, K.R.; DineshKumar, P.K.; Nair, M.

    2010-01-01

    Response of micronekton to oxygen minimum zones in the Arabian Sea (AS) during winter monsoon period was investigated using data of 52 trawls deployed during four winter cruises between 1998 and 2000. Twenty-nine species, representing 19 groups were...

  3. A dairy system based on forages and grazing in temperate Mexico

    OpenAIRE

    Amendola, R.D.

    2002-01-01

    Mexican dairy farmers will face in the near future the challenge of increased competition and the strategy to survive this at farm level will have to be based on competitive free trade world prices. This thesis describes the design of a dairy system based on forages and grazing to reduce production costs in temperate Mexico. This dairy system is based on a sequential cropping system of permanent pastures of alfalfa and orchard grass, winter annual pastures of oats and annual ryegrass and sila...

  4. Soil quality indicators of a mature alley-cropping agroforestry system in temperate North America

    Science.gov (United States)

    Although agroforestry practices are believed to improve soil quality, reports on long-term effects of alley cropping on soils within agroforestry in the temperate zone are limited. The objective of this study was to examine effects of management, landscape, and soil depth of an established agrofores...

  5. Citril finches during the winter: patterns of distribution, the role of pines and implications for the conservation of the species

    Directory of Open Access Journals (Sweden)

    Borras, A.

    2010-06-01

    Full Text Available The Citril finch Serinus citrinella is a Paleartic endemic species that breeds in the subalpine mountain zones of western temperate Europe. The species seems to be suffering a serious decline in its northern range, mainly in the Black Forest and the NE of the Alps. Numerous reasons have been provided for this decline, but all of them have been related to breeding habitats. Given that the species undergoes an altitudinal migration and that during winter it may use very different habitats, a sound knowledge of the distribution patterns and habitats used outside the breeding period is needed to conduct adequate conservation policies and management. This information, however, is largely lacking. The aim of this paper was to determine the current habitat used by Citril finches in north-eastern Spain during the winter, to analyse habitat suitability and to study movements, by investigating the origin of birds that overwinter in Catalonia. Citril finch distribution was modelled using both discriminant analysis and maximum entropy modelling, on the basis of species occurrences during winter in Catalonia (data from 1972-2009. Results showed that the presence of two tree species, Black pine (Pinus nigra subsp. salzmanii and Scots pine (Pinus sylvestris, both as part of mixed open forests, and the presence of abundant farmland and arvensic plants -the two vegetation units located in a typical submediterranean context, where the warm temperatures (sunny days in late winter permit the cones to open-, were the ecological and bioclimatic variables that explain the distribution model. All these variables in tandem seem to be the key for the current potential distribution of the Citril finch in winter (AUCscores: training data AUC= 0.955; test data AUC = 0.953. We analyzed recoveries (N = 238 of 2,368 birds ringed at wintering grounds and 12,648 birds ringed at subalpine localities in the adjacent Pyrenees from 1977-2004. We found that in the study area, we recovered ringed birds from many different locations from across the distributional range of the species, including trans-Pyrenean birds from the Alps. This stresses the high mobility of Citril finch populations to reach wintering areas. From a conservation point of view, the high importance of pines (mainly Black pine for the wintering distribution of the species stresses that any threat on pines, especially forest fires, will have acute detrimental effects for Citril finch populations.

  6. Coastal karren features in temperate microtidal settings: spatial organization and temporal evolution

    OpenAIRE

    Gómez-Pujol, Lluís; Fornós, Joan J

    2010-01-01

    Basin pools are the diagnostic feature of Coastal Karren landscape at temperate settings. According to the size and connectivity parameters four morphological zones are identified along limestone coastal profiles. Each zone reflects the balance between the effects of physical and chemical weathering-erosion agents. Broadly, marine abrasion, bioerosion and biological driven solution show a larger influence seaward, whereas non-biological driven solution enhances its participation landward.

  7. Coastal karren features in temperate microtidal settings: spatial organization and temporal evolution

    Directory of Open Access Journals (Sweden)

    Lluís Gómez-Pujol

    2010-04-01

    Full Text Available Basin pools are the diagnostic feature of Coastal Karren landscape at temperate settings. According to the size and connectivity parameters four morphological zones are identified along limestone coastal profiles. Each zone reflects the balance between the effects of physical and chemical weathering-erosion agents. Broadly, marine abrasion, bioerosion and biological driven solution show a larger influence seaward, whereas non-biological driven solution enhances its participation landward

  8. Resilience of an intertidal infaunal community to winter stressors

    Science.gov (United States)

    Gerwing, Travis G.; Drolet, David; Barbeau, Myriam A.; Hamilton, Diana J.; Allen Gerwing, Alyssa M.

    2015-03-01

    Disturbances can greatly affect densities and richness of biological communities. Given the relatively severe winters in Atlantic Canada, including on mudflats in the Bay of Fundy, winter may be an important structuring force for intertidal infaunal communities. Further, stressors may include effects of sub-zero temperatures, temperature variations, wind, different types of ice, scour, and low sediment oxygen content. We sampled 8 major mudflats in the Bay of Fundy (a macrotidal, temperate system) before (December) and after (March) winter over 2 years, to quantify the biotic community as well as various environmental variables related to both sediment conditions and winter severity. Infaunal communities exhibited significant, but small changes over winter. Furthermore, patterns were not consistent among years, sites or taxa: some taxa decreased in density, others did not change, and a few increased. Finally, the over-winter community change was only weakly correlated to winter stressors. Analysis of the multivariate correlation indicated that physical disturbance of sediments (i.e., scour density and depth, variance in drift ice cover) and sediment oxygen content have the potential to influence community structure. Overall, winter (strictly defined as the period with ice present in our study) did not greatly influence the infaunal community, and the mudflat infaunal community appears resilient to winter stressors.

  9. Mechanism of Secondary Hardening in Rapid Tempering of Dual-Phase Steel

    Science.gov (United States)

    Saha, Dulal Chandra; Nayak, Sashank S.; Biro, Elliot; Gerlich, Adrian P.; Zhou, Y.

    2014-12-01

    Dual-phase steel with ferrite-martensite-bainite microstructure exhibited secondary hardening in the subcritical heat affected zone during fiber laser welding. Rapid isothermal tempering conducted in a Gleeble simulator also indicated occurrence of secondary hardening at 773 K (500 °C), as confirmed by plotting the tempered hardness against the Holloman-Jaffe parameter. Isothermally tempered specimens were characterized by analytic transmission electron microscopy and high-angle annular dark-field imaging. The cementite (Fe3C) and TiC located in the bainite phase of DP steel decomposed upon rapid tempering to form needle-shaped Mo2C (aspect ratio ranging from 10 to 25) and plate-shaped M4C3 carbides giving rise to secondary hardening. Precipitation of these thermodynamically stable and coherent carbides promoted the hardening phenomenon. However, complex carbides were only seen in the tempered bainite and were not detected in the tempered martensite. The martensite phase decomposed into ferrite and spherical Fe3C, and interlath-retained austenite decomposed into ferrite and elongated carbide.

  10. Laser beam welding tempered 300M ultrahigh mechanical strength steel

    Directory of Open Access Journals (Sweden)

    Sheila Medeiros de Carvalho

    2012-03-01

    Full Text Available AISI 300M ultrahigh strength steel has been used in a number of high demanding applications, such as the VLS Brazilian rocket project. This work intends to propose laser beam welding, with subsequent tempering, as a possible route for the fabrication of engineering pieces of this steel. A 2 kW fiber laser was used to produce welded coupons for metallographic, hardness and tensile strength tests. It has been shown that convenient laser parameters for a 3 mm thick plate are 50 mm/s welding speed and 1200 W laser power. However, both welded materials and heat-affected zones presented high hardness and negligible plastic deformation. In order to produce useful engineering parts, it was suggested a tempering treatment for 2 hours at temperatures of 200 or 400ºC. Tensile mechanical testing has shown that welded and tempered coupons presented both yield and maximum strengths comparable to the unwelded material. On the other hand, a maximum elongation of about 4% was obtained, in comparison with 12% from the bulk sample.

  11. Laser beam welding tempered 300M ultrahigh mechanical strength steel

    Scientific Electronic Library Online (English)

    Sheila Medeiros de, Carvalho; Milton Sérgio Fernandes de, Lima.

    2012-03-01

    Full Text Available AISI 300M ultrahigh strength steel has been used in a number of high demanding applications, such as the VLS Brazilian rocket project. This work intends to propose laser beam welding, with subsequent tempering, as a possible route for the fabrication of engineering pieces of this steel. A 2 kW fiber [...] laser was used to produce welded coupons for metallographic, hardness and tensile strength tests. It has been shown that convenient laser parameters for a 3 mm thick plate are 50 mm/s welding speed and 1200 W laser power. However, both welded materials and heat-affected zones presented high hardness and negligible plastic deformation. In order to produce useful engineering parts, it was suggested a tempering treatment for 2 hours at temperatures of 200 or 400ºC. Tensile mechanical testing has shown that welded and tempered coupons presented both yield and maximum strengths comparable to the unwelded material. On the other hand, a maximum elongation of about 4% was obtained, in comparison with 12% from the bulk sample.

  12. PERMEABILITY, WETNESS AND CREEP OF TEMPERATE ICE

    OpenAIRE

    Lliboutry, L.

    1987-01-01

    Ice is said to be temperate when it is in local equilibrium with water veins and water inclusions (1,2). Temperate ice remains a poorly understood material offering a large field for investigation. Pressure solution of air in percolating water explains why, in temperate glaciers, ice becomes progressively bubble-free between 100 and 200 m in depth (3). Emptying of large air bubbles (formed by coalescence of several hundred of small ones) through capillary veins is not excluded, however. Perme...

  13. Vibration failures in tempered steels

    International Nuclear Information System (INIS)

    Comparative measurements of crack propagation in air on three types of tempered steel, ferrite, austenite and an aluminium alloy are described. A clear connection between the crack propagation and the stress ratio cannot be ascertained. Crack arrest occurs when the threshold value of the stress intensity ? K0, determined in tests using a constant range of the crack opening displacement, is reached. The number of striations counted on the cracked surface by microfractographical means was always less than the sum of the stress cycles applied. An accurate conclusion from the striation structure on the history of the fracture is only possible in certain materials under favourable conditions. (orig.)

  14. Vascular plants suitable for wastewater treatment in temperate zones.

    Czech Academy of Sciences Publication Activity Database

    Kv?t, Jan; Dušek, Ji?í; Husák, Št?pán

    Leiden : Backhuys Publishers, 1999 - (Vymazal, J.), s. 101-110 ISBN 90-5782-022-6 R&D Projects: GA ?R GA206/94/1821; GA AV ?R KSK2017602 Keywords : nutrient contens * macrophytes * wastewater treatment Subject RIV: EF - Botanics

  15. Sperm competition in tropical versus temperate zone birds.

    Czech Academy of Sciences Publication Activity Database

    Albrecht, Tomáš; Kleven, O.; Kreisinger, J.; Laskemoen, T.; Omotoriogun, T. C.; Ottosson, U.; Reif, J.; Sedlá?ek, O.; Ho?ák, D.; Robertson, R. J.; Lifjeld, J. T.

    2013-01-01

    Ro?. 280, ?. 1752 (2013), s. 20122434. ISSN 0962-8452 R&D Projects: GA ?R(CZ) GAP505/11/1617; GA ?R(CZ) GAP506/12/2472 Institutional support: RVO:68081766 Keywords : clutch size * extra-pair paternity * life history * post-copulatory sexual selection * sperm phenotype Subject RIV: EG - Zoology Impact factor: 5.292, year: 2013

  16. Performance of a temperate-zone channel catfish biofloc technology

    Science.gov (United States)

    Channel catfish (Ictalurus punctatus) have been grown successfully in an outdoor biofloc technology production system. Outdoor biofloc production systems in the tropics are operated year-round, whereas the channel catfish studies were conducted only during the growing season and biofloc production t...

  17. Microstructure and Mechanical Properties of Laser Clad and Post-cladding Tempered AISI H13 Tool Steel

    Science.gov (United States)

    Telasang, Gururaj; Dutta Majumdar, Jyotsna; Wasekar, Nitin; Padmanabham, G.; Manna, Indranil

    2015-05-01

    This study reports a detailed investigation of the microstructure and mechanical properties (wear resistance and tensile strength) of hardened and tempered AISI H13 tool steel substrate following laser cladding with AISI H13 tool steel powder in as-clad and after post-cladding conventional bulk isothermal tempering [at 823 K (550 °C) for 2 hours] heat treatment. Laser cladding was carried out on AISI H13 tool steel substrate using a 6 kW continuous wave diode laser coupled with fiber delivering an energy density of 133 J/mm2 and equipped with a co-axial powder feeding nozzle capable of feeding powder at the rate of 13.3 × 10-3 g/mm2. Laser clad zone comprises martensite, retained austenite, and carbides, and measures an average hardness of 600 to 650 VHN. Subsequent isothermal tempering converted the microstructure into one with tempered martensite and uniform dispersion of carbides with a hardness of 550 to 650 VHN. Interestingly, laser cladding introduced residual compressive stress of 670 ± 15 MPa, which reduces to 580 ± 20 MPa following isothermal tempering. Micro-tensile testing with specimens machined from the clad zone across or transverse to cladding direction showed high strength but failure in brittle mode. On the other hand, similar testing with samples sectioned from the clad zone parallel or longitudinal to the direction of laser cladding prior to and after post-cladding tempering recorded lower strength but ductile failure with 4.7 and 8 pct elongation, respectively. Wear resistance of the laser surface clad and post-cladding tempered samples (evaluated by fretting wear testing) registered superior performance as compared to that of conventional hardened and tempered AISI H13 tool steel.

  18. Solar Radiation Determines Site Occupancy of Coexisting Tropical and Temperate Deer Species Introduced to New Zealand Forests.

    Science.gov (United States)

    Allen, Robert B; Forsyth, David M; Allen, Roy K J; Affeld, Kathrin; MacKenzie, Darryl I

    2015-01-01

    Assemblages of introduced taxa provide an opportunity to understand how abiotic and biotic factors shape habitat use by coexisting species. We tested hypotheses about habitat selection by two deer species recently introduced to New Zealand's temperate rainforests. We hypothesised that, due to different thermoregulatory abilities, rusa deer (Cervus timorensis; a tropical species) would prefer warmer locations in winter than red deer (Cervus elaphus scoticus; a temperate species). Since adult male rusa deer are aggressive in winter (the rut), we also hypothesised that rusa deer and red deer would not use the same winter locations. Finally, we hypothesised that in summer both species would prefer locations with fertile soils that supported more plant species preferred as food. We used a 250 × 250 m grid of 25 remote cameras to collect images in a 100-ha montane study area over two winters and summers. Plant composition, solar radiation, and soil fertility were also determined for each camera location. Multiseason occupancy models revealed that direct solar radiation was the best predictor of occupancy and detection probabilities for rusa deer in winter. Multistate, multiseason occupancy models provided strong evidence that the detection probability of adult male rusa deer was greater in winter and when other rusa deer were present at a location. Red deer mostly vacated the study area in winter. For the one season that had sufficient camera images of both species (summer 2011) to allow two-species occupancy models to be fitted, the detection probability of rusa deer also increased with solar radiation. Detection probability also varied with plant composition for both deer species. We conclude that habitat use by coexisting tropical and temperate deer species in New Zealand likely depends on the interplay between the thermoregulatory and behavioural traits of the deer and the abiotic and biotic features of the habitat. PMID:26061426

  19. Non Circular Arc Temper Rolling Model Considering Radial And Circumferential Work Roll Displacements

    Science.gov (United States)

    Krimpelstätter, Konrad; Zeman, Klaus; Kainz, Alexander

    2004-06-01

    Compared to usual cold rolling conditions the length of contact between work roll and strip is very short in case of temper rolling. As a consequence, work roll flattening becomes critical even for small contact pressures, and the simplifying assumption of a "circular arc" contour of the deformed work roll cannot be justified anymore. A new temper rolling model is presented applying a non circular arc theory using a semi-analytical procedure for the calculation of the elastic work roll deformations based on numerical superposition of influence functions. In addition to the radial displacements of the work roll, also the circumferential displacements, generated mainly by the shear stresses acting on the work roll surface, are taken into account. The circumferential displacements heavily affect the relative speed (slip speed) between the surfaces of work roll and strip, this speed being a crucial input parameter for any friction law. Hence, the evolution of the shear stresses in the roll gap is re-affected by these circumferential displacements. Their influence is increasing with decreasing temper degrees and cannot be neglected in such cases. The formation of a neutral zone instead of a neutral point is a natural consequence of this approach. The model for the strip is based on Karman's theory. In addition to the elastic compression-, elastic recovery- and plastic zone, also elastic regions are allowed to arise between plastic zones (Internal Elastic Zones). The consequence is that the case of contained plastic flow will appear automatically without additional simplifying assumptions. Simulation results from the new model are presented and discussed. Their comparison with results from FE-simulations shows very good agreement. The model was calibrated against practical data from an existing temper rolling mill. For this purpose extensive temper rolling tests were performed.

  20. Mapping Forest Fire Susceptibility in Temperate Mountain Areas with Expert Knowledge. A Case Study from Iezer Mountains, Romanian Carpathians

    Science.gov (United States)

    Mihai, Bogdan; Savulescu, Ionut

    2014-05-01

    Forest fires in Romanian Carpathians became a frequent phenomenon during the last decade, although local climate and other environmental features did not create typical conditions. From 2004, forest fires affect in Romania more than 100 hectares/year of different forest types (deciduous and coniferous). Their magnitude and frequency are not known, since a historical forest fire inventory does not exist (only press papers and local witness for some selected events). Forest fires features the summer dry periods but there are dry autumns and early winter periods with events of different magnitudes. The application we propose is based on an empirical modeling of forest fire susceptibility in a typical mountain area from the Southern Carpathians, the Iezer Mountains (2462 m). The study area features almost all the altitudinal vegetation zones of the European temperate mountains, from the beech zone, to the coniferous zone, the subalpine and the alpine zones (Mihai et al., 2007). The analysis combines GIS and remote sensing models (Chuvieco et al., 2012), starting from the ideas that forest fires are featured by the ignition zones and then by the fire propagation zones. The first data layer (ignition zones) is the result of the crossing between the ignition factors: lightning - points of multitemporal occurence and anthropogenic activities (grazing, tourism and traffic) and the ignition zones (forest fuel zonation - forest stands, soil cover and topoclimatic factor zonation). This data is modelled from different sources: the MODIS imagery fire product (Hantson et al., 2012), detailed topographic maps, multitemporal orthophotos at 0.5 m resolution, Landsat multispectral imagery, forestry cadastre maps, detailed soil maps, meteorological data (the WorldClim digital database) as well as the field survey (mapping using GPS and local observation). The second data layer (fire propagation zones) is the result of the crossing between the forest fuel zonation, obtained with the help of forestry data, the wind regime data and the topographic features of the mountain area (elevation, slope declivity, slope aspect). The analysis also consider the insolation degree of mountain slopes, that creates favourable conditions for fire propagation between different canopies. These data layers are integrated within a simple GIS analysis in order to intersect the ignition zones with the fire propagation zones in order to obtain the potential areas to be affected by fire. The digital map show three levels of forest fire susceptibility, differenced on the basis of expert knowledge. The map can be validated from the statistical point of view with the polygons of the forest fire affected areas mapped from Landsat TM, ETM+ and OLI satellite imagery. The mapping results could be integrated within the forest management strategies and especially within the forest cadastre and development maps (updated every ten years). The result can confirm that the data gap in terms of forest fire events can be filled with expert knowledge. References Chuvieco, E, Aguado, I., Jurdao, S., Pettinari, M., Yebra, M., Salas, J., Hantson, S., de la Riva, J., Ibarra, P., Rodrigues, M., Echeverria, M., Azqueta, D., Roman, M., Bastarrika, A., Martinez, S., Recondo, C., Zapico, E., Martinez-Vega F.J. (2012) Integrating geospatial information into fire risk assessment, International Journal of Wildland Fire, 2,2, 69-86. Hantson, S., Padilla, M., Corti., D, Chuvieco, E. (2013) Strenghts and weaknesses of MODIS hotspots to characterize Global fire occurence, Remote Sensing of Environment, 131, 1, 152-159. Mihai, B., Savulescu, I.,Sandric, I. (2007) Change detection analysis (1986/2002) for the alpine, subalpine and forest landscape in Iezer Mountains (Southern Carpathians, Romania), Mountain Research and Development, 27, 250-258.

  1. Parallel tempering for the traveling salesman problem

    Energy Technology Data Exchange (ETDEWEB)

    Percus, Allon [Los Alamos National Laboratory; Wang, Richard [UCLA MATH DEPT; Hyman, Jeffrey [UCLA MATH DEPT; Caflisch, Russel [UCLA MATH DEPT

    2008-01-01

    We explore the potential of parallel tempering as a combinatorial optimization method, applying it to the traveling salesman problem. We compare simulation results of parallel tempering with a benchmark implementation of simulated annealing, and study how different choices of parameters affect the relative performance of the two methods. We find that a straightforward implementation of parallel tempering can outperform simulated annealing in several crucial respects. When parameters are chosen appropriately, both methods yield close approximation to the actual minimum distance for an instance with 200 nodes. However, parallel tempering yields more consistently accurate results when a series of independent simulations are performed. Our results suggest that parallel tempering might offer a simple but powerful alternative to simulated annealing for combinatorial optimization problems.

  2. Stamen development and winter dormancy in apricot (Prunus armeniaca)

    OpenAIRE

    Julia?n Lagunas, Carmen; Rodrigo, Javier; Herrero Romero, Mari?a

    2011-01-01

    Background and Aims: In temperate woody perennials, flower bud development is halted during the winter, when the buds enter dormancy. This dormant period is a prerequisite for adequate flowering, is genetically regulated, and plays a clear role in possibly adapting species and cultivars to climatic areas. However, information on the biological events underpinning dormancy is lacking. Stamen development, with clear differentiated stages, appears as a good framework to put dormancy in a develop...

  3. Tempered relaxation with clustering patterns

    International Nuclear Information System (INIS)

    This work is motivated by the relaxation data for materials which exhibit a change of the relationship between the fractional power-law exponents when different relaxation peaks in their dielectric susceptibility are observed. Within the proposed framework we derive a frequency-domain relaxation function fitting the whole range of the two-power-law dielectric spectroscopy data with independent low- and high-frequency fractional exponents ? and ??, respectively. We show that this effect results from a contribution of different processes. For high frequencies it is determined by random stops and movement of relaxing components, and the low-frequency slope is caused by clustering in their temporal changes. -- Highlights: ? Further development in the theory of tempered relaxation. ? Based on the subordination of random processes with finite moments. ? Derived the relaxation function fitting the whole range of two-power-law data. ? Independence of low- and high-frequency fractional exponents in susceptibility.

  4. Developing tempering parameter for ductile cast iron

    International Nuclear Information System (INIS)

    In ductile cast iron (also known as nodular iron or spheroidal graphite cast irons), the graphite is present in tiny spheres or nodules. These ductile cast irons are stronger and has higher elongation than the grey iron or malleable iron, thus have found a wide range of industrial and structural applications. The heat treatment of ductile iron castings produces a significant different properties in mechanical properties from as cast ductile iron. Heat treatment procedures, such as stress relieving, annealing normalizing, quenching and tempering, austempering and surface hardening are the most common for the modification of mechanical properties of ductile irons. Tempered hardness depends upon its as quenched hardness level, alloy contents, tempering temperature and time. The focus of this paper is the quantitative aspects of quenching and tempering, and explaining a strategy to develop a master curve to correlate time, tempering temperature and hardness. This master curve is based upon defining a tempering parameters, which is similar in mathematical structure to the Larson-Miller Parameter in creep. Such a parameter has been successfully used in defining the tempering response of a variaety of steels, and have been found to be applicable also in the cse of cast iron. (author) 6 figs

  5. Appropriate welding conditions of temper bead weld repair for SQV2A pressure vessel steel

    Energy Technology Data Exchange (ETDEWEB)

    Mizuno, R.; Matsuda, F. [NDE Center, Japan Power Engineering and Inspection Corp. (Japan); Brziak, P. [Welding Research Inst. - Industrial Inst. of Slovak Republic (Slovakia); Lomozik, M. [Inst. of Welding (Poland)

    2004-07-01

    Temper bead welding technique is one of the most important repair welding methods for large structures for which it is difficult to perform the specified post weld heat treatment. In this study, appropriate temper bead welding conditions to improve the characteristics of heat affected zone (HAZ) are studied using pressure vessel steel SQV2A corresponding to ASTM A533 Type B Class 1. Thermal/mechanical simulator is employed to give specimens welding thermal cycles from single to quadruple cycle. Charpy absorbed energy and hardness of simulated CGHAZ by first cycle were degraded as compared with base metal. Improvability of these degradations by subsequent cycles is discussed and appropriate temper bead thermal cycles are clarified. When the peak temperature lower than Ac1 and near Ac1 in the second thermal cycle is applied to CGAHZ by first thermal cycle, the characteristics of CGHAZ improve enough. When the other peak temperatures (that is, higher than Ac1) in the second thermal cycle are applied to the CGHAZ, third or more thermal cycle temper bead process should be applied to improve the properties. Appropriate weld condition ranges are selected based on the above results. The validity of the selected ranges is verified by the temper bead welding test. (orig.)

  6. Appropriate welding conditions of temper bead weld repair for SQV2A pressure vessel steel

    International Nuclear Information System (INIS)

    Temper bead welding technique is one of the most important repair welding methods for large structures for which it is difficult to perform the specified post weld heat treatment. In this study, appropriate temper bead welding conditions to improve the characteristics of heat affected zone (HAZ) are studied using pressure vessel steel SQV2A corresponding to ASTM A533 Type B Class 1. Thermal/mechanical simulator is employed to give specimens welding thermal cycles from single to quadruple cycle. Charpy absorbed energy and hardness of simulated CGHAZ by first cycle were degraded as compared with base metal. Improvability of these degradations by subsequent cycles is discussed and appropriate temper bead thermal cycles are clarified. When the peak temperature lower than Ac1 and near Ac1 in the second thermal cycle is applied to CGAHZ by first thermal cycle, the characteristics of CGHAZ improve enough. When the other peak temperatures (that is, higher than Ac1) in the second thermal cycle are applied to the CGHAZ, third or more thermal cycle temper bead process should be applied to improve the properties. Appropriate weld condition ranges are selected based on the above results. The validity of the selected ranges is verified by the temper bead welding test. (orig.)

  7. Woodland communities in the Chilean cold-temperate zone (Baker and Pascua basins: Floristic composition and morpho-ecological transition Comunidades leñosas en la zona chilena frío-templada (cuencas de los ríos Baker y Pascua: Composición florística y transición morfo-ecológica

    Directory of Open Access Journals (Sweden)

    OSVALDO J VIDAL

    2011-01-01

    Full Text Available This study describes the floristic composition and morpho-ecological transition of woodlands along a climatic gradient in the southern cold temperate zone of Chilean Patagonia. A total of 256 phytosociological relevés were performed across a 150 km NE-SW transect to record vascular plant species. Classification (cluster analysis and ordination (principal component analysis techniques were used to segregate and examine the communities. Biodiversity indicators including richness and abundances of species natives and exotics, importance values, Raunkiaer plant life-forms, diversity indices and indicator species were calculated to describe community attributes. Beta diversity was analysed using the Jaccard index. Additionally, the current anthropogenic disturbances affecting this vegetation are discussed. In total, 11 woodland communities belonging to 3 morpho-ecological groups were segregated: a meso-hygromorphic woodlands belonging to the Baker basin, mostly composed of deciduous forests containing relatively moderate values of richness and diversity but high richness of exotics, b hygromorphic woodlands belonging to the southern segment of the Baker basin and along the Pascua basin, composed of evergreen forest containing the relatively highest values of richness and diversity and very low richness of exotics and c high-Andean dwarf woodlands distributed at high elevations in both basins, composed of deciduous krummholz containing the lowest richness and diversity and no exotics. The replacement of deciduous by evergreen communities at low elevations occurs around the latitude 48°S. Anthropogenic disturbances like logging by rural landowners, overgrazing by livestock and road construction are promoting biological invasions in the Baker basin forests, while the forests in the Pascua basin remain pristine since no human population occurs thereEste estudio describe la composición florística y la transición morfo-ecológica de las comunidades leñosas ocurriendo a través de un gradiente climático en la zona templada fría de la Patagonia chilena. Se establecieron un total de 256 relevamientos fitosociológicos a través de un transecto NE-SO de 150 km para registrar las especies de plantas vasculares. Técnicas de clasificación (análisis de conglomerados y ordenación (análisis de componentes principales fueron usadas para segregar y examinar comunidades. Se computaron indicadores de biodiversidad incluyendo riqueza y abundancia de especies nativas y exóticas, valores de importancia, formas de vida de Raunkiaer, índices de diversidad y especies indicadoras para describir atributos comunitarios. La diversidad Beta fue analizada usando el coeficiente de Jaccard. Se discuten también las perturbaciones antropogénicas que actualmente afectan a la vegetación. En total se segregaron 11 comunidades pertenecientes a tres grupos ecológicos: a comunidades leñosas meso-higromórficas pertenecientes a la cuenca del Baker, conformada principalmente de bosques caducifolios conteniendo valores relativos intermedios de riqueza y diversidad, pero las mayores riquezas de exóticas; b comunidades leñosas higromórficas pertenecientes al segmento sur de la cuenca del río Baker y a través de toda la cuenca del río Pascua, compuesta de bosques siempreverdes conteniendo los mayores valores de riqueza y diversidad y muy baja riqueza de exóticas, y c comunidades leñosas achaparradas alto-andinas, distribuidas en lugares de alta elevación en ambas cuencas, compuestas de krummholz conteniendo la menor riqueza y diversidad, sin presencia de especies introducidas. El reemplazo de comunidades caduficolias por siempreverdes en sentido norte-sur sucede alrededor de la latitud 48°S. Perturbaciones antrópicas como la tala de madera por propietarios rurales, sobrepastoreo por ganado doméstico y ampliaciones en los caminos, están provocando invasiones biológicas en los bosques de la cuenca del río Baker, mientras que los bosques de la cuenca del río Pascua, donde no ocurre poblamiento humano, permanecen prístin

  8. Woodland communities in the Chilean cold-temperate zone (Baker and Pascua basins): Floristic composition and morpho-ecological transition / Comunidades leñosas en la zona chilena frío-templada (cuencas de los ríos Baker y Pascua): Composición florística y transición morfo-ecológica

    Scientific Electronic Library Online (English)

    OSVALDO J, VIDAL; JAN R, BANNISTER; VÍCTOR, SANDOVAL; YESSICA, PÉREZ; CARLOS, RAMÍREZ.

    Full Text Available Este estudio describe la composición florística y la transición morfo-ecológica de las comunidades leñosas ocurriendo a través de un gradiente climático en la zona templada fría de la Patagonia chilena. Se establecieron un total de 256 relevamientos fitosociológicos a través de un transecto NE-SO de [...] 150 km para registrar las especies de plantas vasculares. Técnicas de clasificación (análisis de conglomerados) y ordenación (análisis de componentes principales) fueron usadas para segregar y examinar comunidades. Se computaron indicadores de biodiversidad incluyendo riqueza y abundancia de especies nativas y exóticas, valores de importancia, formas de vida de Raunkiaer, índices de diversidad y especies indicadoras para describir atributos comunitarios. La diversidad Beta fue analizada usando el coeficiente de Jaccard. Se discuten también las perturbaciones antropogénicas que actualmente afectan a la vegetación. En total se segregaron 11 comunidades pertenecientes a tres grupos ecológicos: a) comunidades leñosas meso-higromórficas pertenecientes a la cuenca del Baker, conformada principalmente de bosques caducifolios conteniendo valores relativos intermedios de riqueza y diversidad, pero las mayores riquezas de exóticas; b) comunidades leñosas higromórficas pertenecientes al segmento sur de la cuenca del río Baker y a través de toda la cuenca del río Pascua, compuesta de bosques siempreverdes conteniendo los mayores valores de riqueza y diversidad y muy baja riqueza de exóticas, y c) comunidades leñosas achaparradas alto-andinas, distribuidas en lugares de alta elevación en ambas cuencas, compuestas de krummholz conteniendo la menor riqueza y diversidad, sin presencia de especies introducidas. El reemplazo de comunidades caduficolias por siempreverdes en sentido norte-sur sucede alrededor de la latitud 48°S. Perturbaciones antrópicas como la tala de madera por propietarios rurales, sobrepastoreo por ganado doméstico y ampliaciones en los caminos, están provocando invasiones biológicas en los bosques de la cuenca del río Baker, mientras que los bosques de la cuenca del río Pascua, donde no ocurre poblamiento humano, permanecen prístinos Abstract in english This study describes the floristic composition and morpho-ecological transition of woodlands along a climatic gradient in the southern cold temperate zone of Chilean Patagonia. A total of 256 phytosociological relevés were performed across a 150 km NE-SW transect to record vascular plant species. Cl [...] assification (cluster analysis) and ordination (principal component analysis) techniques were used to segregate and examine the communities. Biodiversity indicators including richness and abundances of species natives and exotics, importance values, Raunkiaer plant life-forms, diversity indices and indicator species were calculated to describe community attributes. Beta diversity was analysed using the Jaccard index. Additionally, the current anthropogenic disturbances affecting this vegetation are discussed. In total, 11 woodland communities belonging to 3 morpho-ecological groups were segregated: a) meso-hygromorphic woodlands belonging to the Baker basin, mostly composed of deciduous forests containing relatively moderate values of richness and diversity but high richness of exotics, b) hygromorphic woodlands belonging to the southern segment of the Baker basin and along the Pascua basin, composed of evergreen forest containing the relatively highest values of richness and diversity and very low richness of exotics and c) high-Andean dwarf woodlands distributed at high elevations in both basins, composed of deciduous krummholz containing the lowest richness and diversity and no exotics. The replacement of deciduous by evergreen communities at low elevations occurs around the latitude 48°S. Anthropogenic disturbances like logging by rural landowners, overgrazing by livestock and road construction are promoting biological invasions in the Baker basin forests, while the forests in the Pascua basin remain p

  9. Climatic forcing of carbon-oxygen isotopic covariance in temperate-region marl lakes

    Science.gov (United States)

    Drummond, C. N.; Patterson, W. P.; Walker, J. C.

    1995-01-01

    Carbon and oxygen stable isotopic compositions of lacustrine carbonate from a southeastern Michigan marl lake display linear covariance over a range of 4.0% Peedee belemnite (PDB) in oxygen and 3.9% (PDB) in carbon. Mechanisms of delta 13 C-delta 18 O coupling conventionally attributed to lake closure in arid-region basins are inapplicable to hydrologically open lake systems. Thus, an alternative explanation of isotopic covariance in temperate region dimictic marl lakes is required. We propose that isotopic covariance is a direct record of change in regional climate. In short-residence-time temperate-region lake basins, summer meteoric precipitation is enriched in 18O relative to winter values, and summer organic productivity enriches epilimnic dissolved inorganic carbon in 13C. Thus, climate change toward longer summers and/or shorter winters could result in greater proportions of warm-month meteoric precipitation, longer durations of warm-month productivity, and net long-term enrichment in carbonate 18O and 13C. Isotopic covariance observed in the Michigan marl lake cores is interpreted to reflect postglacial warming from 10 to 3 ka followed by cooler mean annual temperature, a shift toward greater proportions of seasonal summer precipitation, a shortening of the winter season, or some combination of these three factors.

  10. Results from the UKQCD Parallel Tempering project

    International Nuclear Information System (INIS)

    We present results from our study of the Parallel Tempering algorithm. We examine the swapping acceptance rate of a twin subensemble PT system. We use action matching technology in an attempt to maximise the swap acceptance rate. We model the autocorrelation times within Parallel Tempering ensembles in terms of autocorrelation times from Hybrid Monte Carlo. We present estimates for the autocorrelation times of the plaquette operator

  11. Variation in leaf flushing date influences autumnal senescence and next year’s flushing date in two temperate tree species

    OpenAIRE

    Fu, Yongshuo S. H.; Campioli, Matteo; Vitasse, Yann; Boeck, Hans J.; Den Berge, Joke; Abdelgawad, Hamada; Asard, Han; Piao, Shilong; Deckmyn, Gaby; Janssens, Ivan A.

    2014-01-01

    Leaf phenology of temperate ecosystems is shifting in response to global warming. This affects surface albedo, ecosystem carbon balance, and evapotranspiration, and the response of leaf phenology to climatic drivers has therefore received particular interest. However, despite considerable effort, models have failed to accurately reproduce phenology patterns, likely because mechanistic understanding is incomplete. Here, we show that earlier leaf flushing in response to a warm winter translated...

  12. Concussion in Winter Sports

    Science.gov (United States)

    ... Button Past Emails CDC Features Concussion in Winter Sports Recommend on Facebook Tweet Share Compartir Get prepared ... to enjoy, practice, and compete in various winter sports. There's no doubt that these sports are a ...

  13. Winter's law again

    OpenAIRE

    Kortlandt, Frederik H. H.

    2010-01-01

    Since I discussed the scholarly literature on Winter’s law twenty years ago (1988), several important articles on the subject have appeared (Young 1990, Campanile 1994, Matasovic 1995, Derksen 2002, Dybo 2002, Patri 2005, Derksen 2007). As the law evidently continues to be controversial, it is important to look into the nature of the evidence and counter-evidence which is adduced. It appears that doubts about Winter’s law are largely the result of four types of misunderstanding.

  14. Phenotypic variation of Fucus ceranoides, F. spiralis and F. vesiculosus in a temperate coast (NW Portugal)

    OpenAIRE

    Cairra?o, E.; Pereira, M. J.; Morgado, F.; Nogueira, A. J. A.; Guilhermino, L.; Soares, A. M. V. M.

    2009-01-01

    Brown algae includes several species of Fucus, reported both in the tidal and intertidal zones of cold and temperate regions. Environmental parameters induce wide biological variability in intertidal algae, manifested by alterations at several levels, and this has lead to the failure of some reports to discriminate between closely related taxa, particularly Fucus species. As the genus Fucus is widely represented on the Portuguese coast, the biometric parameters of three species (F spiralis, F...

  15. Postglacial evolution and spatial differentiation of seasonal temperate rainforest in western Canada

    OpenAIRE

    Brown, K. J.; Nielsen, Anne Birgitte; Fitton, R. J.; Hebda, R. J.

    2008-01-01

    Surface samples from Vancouver Island, Canada, were used to assess the relationship between discrete seasonal temperate rainforest (STR) plant communities and their corresponding pollen signatures. Pollen from ten sediment cores was further used to evaluate the postglacial development of these communities. Principal components analysis (PCA) of the surface data revealed the distinctiveness of the modern pollen rain, with samples from the Coastal Douglas Fir (CDF) zone, the dry Coastal Western...

  16. Plasmodium vivax populations revisited: mitochondrial genomes of temperate strains in Asia suggest ancient population expansion

    Directory of Open Access Journals (Sweden)

    Miao Miao

    2012-02-01

    Full Text Available Abstract Background Plasmodium vivax is the most widely distributed human malaria parasite outside of Africa, and its range extends well into the temperate zones. Previous studies provided evidence for vivax population differentiation, but temperate vivax parasites were not well represented in these analyses. Here we address this deficit by using complete mitochondrial (mt genome sequences to elucidate the broad genetic diversity and population structure of P. vivax from temperate regions in East and Southeast Asia. Results From the complete mtDNA sequences of 99 clinical samples collected in China, Myanmar and Korea, a total of 30 different haplotypes were identified from 26 polymorphic sites. Significant differentiation between different East and Southeast Asian parasite populations was observed except for the comparison between populations from Korea and southern China. Haplotype patterns and structure diversity analysis showed coexistence of two different groups in East Asia, which were genetically related to the Southeast Asian population and Myanmar population, respectively. The demographic history of P. vivax, examined using neutrality tests and mismatch distribution analyses, revealed population expansion events across the entire P. vivax range and the Myanmar population. Bayesian skyline analysis further supported the occurrence of ancient P. vivax population expansion. Conclusions This study provided further resolution of the population structure and evolution of P. vivax, especially in temperate/warm-temperate endemic areas of Asia. The results revealed divergence of the P. vivax populations in temperate regions of China and Korea from other populations. Multiple analyses confirmed ancient population expansion of this parasite. The extensive genetic diversity of the P. vivax populations is consistent with phenotypic plasticity of the parasites, which has implications for malaria control.

  17. Raising the temper-?-spot analysis of temper inclusions in experimental ceramics

    International Nuclear Information System (INIS)

    Provenancing of ancient ceramics is a highly important scientific tool for archaeological studies. In general, ceramics are not made from the original clay as it is found in deposits. To produce the needed physical properties in the finished product, the clay has to be either tempered by adding sands or biological materials, or levigated, to remove the coarse fraction. Thus, the chemical composition of the finished ceramic differs from the composition of the original clay bed. To overcome this obfuscation, any information that can be gained about the temper is useful. In a small series, several pieces of ceramic were produced from known clay and tempers and the resulting ceramics analysed by neutron activation analysis (NAA). As many attempts to physically separate the temper from the clay matrix have failed, ?-spot analysis of temper inclusions was performed at the microbeam particle induced X-ray Emission (?-PIXE) facility in Rossendorf and with laser ablation inductively coupled plasma mass spectroscopy (LA-ICP-MS) at the Aberystwyth University in Wales. It could be shown that from a small number of measurements, a general impression of the temper used could be gained. Furthermore the ?-spot methods and the bulk data gained from INAA are highly comparable, extending the set of elements that can be measured. With this information, the influence of the temper on the bulk composition of the finished product can be estimated, which potentially adds crucial informatihich potentially adds crucial information to subsequent dilution calculations. (author)

  18. A Transnational Temperance Discourse? William Wells Brown, Creole Civilization, and Temperate Manners

    Directory of Open Access Journals (Sweden)

    Carole Lynn Stewart

    2011-03-01

    Full Text Available

    In the nineteenth century, temperance movements provided the occasion for a transnational discourse. These conversations possessed an intensity throughout Britain and the United States. In America temperance often became associated with strongly nationalistic Euro-American forms of identity and internal purity. Nonetheless, African American reformers and abolitionists bound themselves to temperance ideals in forming civil societies that would heal persons and provide communal modes of democratic freedom in the aftermath and recovery from chattel slavery. This paper explores the possibilities of temperance as a transnational discourse by considering its meaning in the life and work of the African American author and activist, William Wells Brown. Brown expressed a “creole civilization” that employed the stylistics of the trickster as a unique mode of restraint that revealed a peculiar power of passivity that was able to claim efficacy over one’s life and community. This meaning of temperance diverges from and dovetails with certain European meanings of civilization that were being forged in the nineteenth century. Brown was in conversation with temperance reformers in America, Britain, and Europe. He imagined the possible meaning of temperance in African, Egyptian, Christian, and Islamic civilizations. He speculated upon the possibility of temperance as a defining characteristic of a transnational civilization and culture that would provide spaces for the expression of democratic freedom. Brown reimagined temperance as a form of corporeal restraint that offered a direct and sacred relation to the land, space, people that appeared in between an ethnic nationalist ethos and the European imperialistic civilization.

  19. Acoplamiento pelágico-bentónico: respuesta de la zona bentónica profunda a la sedimentación del florecimiento invernal de diatomeas en el lago oligotrófico Alchichica, Puebla, México Pelagic-benthic coupling: deep benthic zone response to winter diatom bloom sinking in oligotrophic Lake Alchichica, Puebla, Mexico

    Directory of Open Access Journals (Sweden)

    Javier Alcocer

    2008-08-01

    Full Text Available El objetivo del presente estudio es reconocer la existencia de un acoplamiento pelágico-bentónico en el lago oligotrófico tropical Alchichica evaluando la respuesta de la zona bentónica profunda a la sedimentación del florecimiento invernal de diatomeas. Se midió la biomasa fitoplanctónica en la columna de agua a lo largo de un ciclo anual, al igual que la concentración de clorofila a sedimentaria. Alchichica es un lago monomíctico cálido con un periodo de circulación invernal y estratificación el resto del año. La presencia de turbulencia y nutrimentos durante el periodo de circulación favorecen el desarrollo de un florecimiento de diatomeas compuesto por especies de talla grande (p. e., Cyclotella alchichicana, las cuales se sedimentan al no ser consumidas en su totalidad. La zona bentónica profunda del lago responde a la sedimentación del florecimiento invernal de diatomeas con el desarrollo y permanencia por un periodo prolongado de anoxia hipolimnética, lo que a su vez, impide el establecimiento y desarrollo de fauna bentónica en el Lago Alchichica, favorece la pérdida interna de nitrógeno por desnitrificación y consecuentemente, conlleva a que el nitrógeno sea el elemento que más frecuentemente límite el crecimiento fitoplanctónico.The aim of this study is to recognize the existence of a pelagic-benthic coupling in the oligotrophic, tropical Lake Alchichica through analysis of the response of the deep benthic zone to the winter diatom bloom deposition. The water column phytoplankton biomass and the sedimentary chlorophyll a were analyzed along an annual cycle. Alchichica is a warm monomictic lake circulating in winter and stratified over the rest of the year. The presence of turbulence and nutrient availability during the mixing period, favor the development of a diatom bloom composed by large species (e. g., Cyclotella alchichicana which are not totally consumed and settle down. The deep benthic zone responds to the sinking of the winter diatom bloom with the prompt development -and permanence for an extended period- of hypolimnetic anoxia, which in turns prevents the establishment and development of the benthic fauna in Lake Alchichica, and favors the internal loss of nitrogen through denitrification, and accordingly, promotes nitrogen to be the limiting nutrient for phytoplankton growth.

  20. Acoplamiento pelágico-bentónico: respuesta de la zona bentónica profunda a la sedimentación del florecimiento invernal de diatomeas en el lago oligotrófico Alchichica, Puebla, México / Pelagic-benthic coupling: deep benthic zone response to winter diatom bloom sinking in oligotrophic Lake Alchichica, Puebla, Mexico

    Scientific Electronic Library Online (English)

    Javier, Alcocer; Elva, Escobar; Luis A., Oseguera.

    2008-08-01

    Full Text Available El objetivo del presente estudio es reconocer la existencia de un acoplamiento pelágico-bentónico en el lago oligotrófico tropical Alchichica evaluando la respuesta de la zona bentónica profunda a la sedimentación del florecimiento invernal de diatomeas. Se midió la biomasa fitoplanctónica en la col [...] umna de agua a lo largo de un ciclo anual, al igual que la concentración de clorofila a sedimentaria. Alchichica es un lago monomíctico cálido con un periodo de circulación invernal y estratificación el resto del año. La presencia de turbulencia y nutrimentos durante el periodo de circulación favorecen el desarrollo de un florecimiento de diatomeas compuesto por especies de talla grande (p. e., Cyclotella alchichicana), las cuales se sedimentan al no ser consumidas en su totalidad. La zona bentónica profunda del lago responde a la sedimentación del florecimiento invernal de diatomeas con el desarrollo y permanencia por un periodo prolongado de anoxia hipolimnética, lo que a su vez, impide el establecimiento y desarrollo de fauna bentónica en el Lago Alchichica, favorece la pérdida interna de nitrógeno por desnitrificación y consecuentemente, conlleva a que el nitrógeno sea el elemento que más frecuentemente límite el crecimiento fitoplanctónico. Abstract in english The aim of this study is to recognize the existence of a pelagic-benthic coupling in the oligotrophic, tropical Lake Alchichica through analysis of the response of the deep benthic zone to the winter diatom bloom deposition. The water column phytoplankton biomass and the sedimentary chlorophyll a we [...] re analyzed along an annual cycle. Alchichica is a warm monomictic lake circulating in winter and stratified over the rest of the year. The presence of turbulence and nutrient availability during the mixing period, favor the development of a diatom bloom composed by large species (e. g., Cyclotella alchichicana) which are not totally consumed and settle down. The deep benthic zone responds to the sinking of the winter diatom bloom with the prompt development -and permanence for an extended period- of hypolimnetic anoxia, which in turns prevents the establishment and development of the benthic fauna in Lake Alchichica, and favors the internal loss of nitrogen through denitrification, and accordingly, promotes nitrogen to be the limiting nutrient for phytoplankton growth.

  1. Plant nutrient mobilization in temperate heathland responds to elevated CO2, temperature and drought

    DEFF Research Database (Denmark)

    Andresen, Louise C.; Michelsen, Anders

    2010-01-01

    Temperate terrestrial ecosystems are currently exposed to increased atmospheric CO2 and progressive climatic changes with increased temperature and periodical drought. We here present results from a field experiment, where the effects of these three main climate change related factors are investigated solely and in all combinations at a temperate heathland. Significant responses were found in the top soils below the two dominant species (Calluna vulgaris and Deschampsia flexuosa). During winter incubation, microbial immobilization of N and ammonification rate decreased in response to warming in Deschampsia soil, and microbial immobilization of N and P decreased in warmed Calluna soil. Warming tended to increase microbial N and P in Calluna but not in Deschampsia soil in fall, and more microbial C was accumulated under drought in Calluna soil. The effects of warming were often counteracted or erased when combined with CO2 and drought. Below Deschampsia, the net nitrification rate decreased in response to drought and, while phosphorus availability and microbial P immobilization decreased, but nitrification increased in response to elevated CO2. Furthermore, leaf litter decomposition of both species decreased in response to drought. These complex changes in availability and release of nutrients from soil organic matter turnover and mineralization in response to elevated CO2 and climate change may influence the future plant carbon sequestration and species composition at temperate heathlands.

  2. Temper embrittlement of heavy wall 3.5Ni- Cr- Mo steel forgings for pressure vessels

    International Nuclear Information System (INIS)

    3.5Ni- Cr- Mo steel forging is used as the pressure vessel material with high strength and toughness. The steel is well known to have high susceptibility to temper embrittlement due to its high Ni and Cr content. The effect of chemical compositions on temper embrittlement of the heavy wall 3.5Ni- Cr- Mo steel forging was investigated. The susceptivility of the forging to temper embrittlement induced slow cooling from post - weld - heat - treatment temperature or step cooling treatment increased with increasing the contents of Si, Mn and impurity elements but was not influenced by C, Ni and V contents. The degree of embrittlement of weld heat - affected zone was larger than that of base material induced by slow cooling from PWHT temperature. The critical value of (2Si + Mn) ·X-bar, where X-bar = 10P + 5Sb + 4Sn + As, ppm/100, is about 8.5 to satisfy the specification requirement of SA508 class 4 for the weld heat - affected zone after PWHT with cooling rate of 40 deg C/hr. The shift in FATT due to step cooling treatment was larger than that due to slow cooling from PWHT temperature. The critical value of (2Si + Mn) ·X-bar was about 4.5 to satisfy the specification requirement after step cooling treatment. (author)

  3. Annual CO2 balance of a temperate bog

    International Nuclear Information System (INIS)

    Peatlands are generally small sinks for atmospheric CO2. However, the sustainability of this sink functioning is threatened in a changing climate. We measured the CO2 exchange in a temperate bog between August 2005 and July 2006 using the eddy covariance technique. During this period, the CO2 balance was -78.6 ± 20.0 g CO2/m2/yr, which is a lower uptake than others have reported for comparable ecosystems, but in accordance with average Holocene uptake rates. Average winter emissions were small (11 ?g CO2 /m2/s), but the accumulated non-growing season fluxes (121 g CO2/m2) represent a larger flux than the annual balance. Taking into consideration that wintertime temperatures in the northern hemisphere are expected to increase in the future, wintertime fluxes may become increasingly important. The highest instantaneous monthly average uptake occurred in June (-38 ?g CO2 /m2/s), while the drier month of July showed a distinctly smaller sink (-22 ?g CO2 /m2/s). It is suggested that soil drying caused gross primary production to decline, while nighttime respiration showed a steadily increase. Our findings indicate that the effect of future warmer temperatures on the growing season CO2 exchange in peatlands is dependent on soil wetness

  4. A Facies Model for Temperate Continental Glaciers.

    Science.gov (United States)

    Ashley, Gail Mowry

    1987-01-01

    Discusses the presence and dynamics of continental glaciers in the domination of the physical processes of erosion and deposition in the mid-latitudes during the Pleistocene period. Describes the use of a sedimentary facies model as a guide to recognizing ancient temperate continental glacial deposits. (TW)

  5. The Temperance Movement and Social Work

    Science.gov (United States)

    Murdach, Allison D.

    2009-01-01

    This article examines a forgotten episode in social work history: the involvement of the profession in the temperance movement in the late 19th and early 20th centuries. Though some notable social workers such as Jane Addams, Robert A. Woods, and Representative Jeannette Rankin (the first woman elected to the U.S. Congress), championed the…

  6. Nuclear winter down under

    International Nuclear Information System (INIS)

    The radiation that nuclear explosions produce and the subsequent fall-out play a relatively small part in the causes and consequences of a nuclear winter. More important are the injection of smoke and dust into the upper atmosphere and the subsequent effects on climate and agricultural productivity. The implications of nuclear winter for the Southern Hemisphere and Australia in particular, are examined

  7. Winter Math Activities

    Science.gov (United States)

    Terry Kawas

    2013-01-01

    This webpage of winter math activities includes seasonal activities for patterns, graphing, symmetry, estimations, and glyphs. Other resources on this page include literature connections, links to more winter resources, and pictures of student work. Activities are centered on penguins, snowflakes, snowman, and gingerbread.

  8. Winter Olympic Sports

    Science.gov (United States)

    Mrs. Keller

    2010-01-23

    Exploring Winter Olympic Sports Let's take a look at some of the different winter olympic sports Alpine Skiing Biathalon Bobsleigh Cross country Curling Figure Skating Freestyle skiing Ice Hockey Luge Nordic Combined Short track speed skating Skeleton Ski Jumping Snowboard Speed Skating ...

  9. Effects of temper condition and corrosion on the fatigue performance of a laser-welded Al-Cu-Mg-Ag (2139) alloy

    International Nuclear Information System (INIS)

    The effects of temper condition and corrosion on the fatigue behavior of a laser beam welded Al-Cu-Mg-Ag alloy (2139) have been investigated. Natural aging (T3 temper) and artificial aging (T8 temper) have been applied prior to welding. Corrosion testing has been performed by exposing the welded specimens to a salt spray medium for 720 h. Aging influences the corrosion behavior of laser welds. In the T3 temper, corrosion attack is in the form of pitting in the weld area, while in the T8 temper corrosion is in the form of pitting and intergranular corrosion in the base metal. In the latter case corrosion is attributed to the presence of grain boundary precipitates. Corrosion degrades the fatigue behavior of 2139 welds. The degradation is equal for both the T3 and T8 tempers and for the corrosion exposure selected in this study corresponds to a 52% reduction in fatigue limit. In both cases fatigue crack initiation is associated with corrosion pits, which act as stress raisers. In the T3 temper, the fatigue crack initiation site is at the weld metal/heat affected zone interface, while for the T8 temper the initiation site is at the base metal. Fatigue crack initiation in uncorroded 2139 welds occurs at the weld toe at the root side, the weld reinforcement playing a principal role as stress concentration site. The fatigue crack propagates through the partially melted zone and the weld metal in all cases. The findings in this paper present useful information for the selection of appropriate heat treatment conditions, to facilitate control of the corrosion behavior in aluminium welds, which is of great significance for their fatigue performance.

  10. Winters fuels report

    International Nuclear Information System (INIS)

    The outlook for distillate fuel oil this winter is for increased demand and a return to normal inventory patterns, assuming a resumption of normal, cooler weather than last winter. With industrial production expected to grow slightly from last winter's pace, overall consumption is projected to increase 3 percent from last winter, to 3.4 million barrels per day during the heating season (October 1, 1995-March 31, 1996). Much of the supply win come from stock drawdowns and refinery production. Estimates for the winter are from the Energy Information Administration's (EIA) 4th Quarter 1995 Short-Tenn Energy Outlook (STEO) Mid-World Oil Price Case forecast. Inventories in place on September 30, 1995, of 132 million barrels were 9 percent below the unusually high year-earlier level. Inventories of high-sulfur distillate fuel oil, the principal type used for heating, were 13 percent lower than a year earlier. Supply problems are not anticipated because refinery production and the ready availability of imports should be adequate to meet demand. Residential heating off prices are expected to be somewhat higher than last winter's, as the effects of lower crude oil prices are offset by lower distillate inventories. Heating oil is forecast to average $0.92 per gallon, the highest price since the winter of 1992-93. Diesel fuel (including tax) is predicted to be slightly higher than last year at $1.13 per gallon. This article focuses on the winter assessment for distillate fuel oil, how well last year's STEO winter outlook compared to actual events, and expectations for the coming winter. Additional analyses include regional low-sulfur and high-sulfur distillate supply, demand, and prices, and recent trends in distillate fuel oil inventories

  11. Hydrology and morphology of two river mouth regions (temperate Vistula Delta and subtropical Red River Delta

    Directory of Open Access Journals (Sweden)

    Zbigniew Pruszak

    2005-09-01

    Full Text Available The paper presents a comparative analysis of two different river mouths from two different geographical zones (subtropical and temperate climatic regions. One is the multi-branch and multi-spit mouth of the Red River on the Gulf of Tonkin (Vietnam, the other is the smaller delta of the river Vistula on a bay of the Baltic Sea (Poland. The analysis focuses on the similarities and differences in the hydrodynamics between these estuaries and the adjacent coastal zones, the features of sediment transport, and the long-term morphodynamics of the river outlets. Salinity and water level are also discussed, the latter also in the context of the anticipated global effect of accelerated sea level rise. The analysis shows that the climatic and environmental conditions associated with geographical zones give rise to fundamental differences in the generation and dynamic evolution of the river mouths.

  12. AGEING AND TEMPERING OF FERROUS MARTENSITES

    OpenAIRE

    Chang, Li; Smith, G.; Olson, G.

    1986-01-01

    The low temperature ageing of a Fe-15wt%Ni-1wt%C martensite (Ms temperature -35 C) has been investigated using field - ion microscopy and atom probe microanalytical techniques. It is demonstrated that both the amplitude and the wavelength of the carbon composition fluctuations observed during room-temperature ageing increase with time, indicating that the alloy decomposes by a spinodal process. The carbon-rich regions approach a limiting composition of Fe8C during this reaction. The tempering...

  13. Lightweight dividing walls : adaptation to temperate climates

    OpenAIRE

    Mendonc?a, Paulo; Macieira, Mo?nica

    2011-01-01

    This paper intends to prove that it is possible to use lightweight membranes on interior partition walls and on external façades, even in housing buildings at temperate climate regions, if their properties are well explored. The few material used, even less than conventional lightweight solutions - the most common is plasterboard with light steel frame structure - allow a lower specific embodied energy and other more favourable environmental impact indicators. Compared to conventional heavyw...

  14. TEMPERANCE MOVEMENT IN TAMILNADU, 1930-1934

    OpenAIRE

    Kasthuri, A.

    2014-01-01

    The Civil Disobedience Movement made its appearance in the country In March 1930. One of the major off shoots was temperance movement. The purpose of the movement was to cripple the revenue to the British by the sale of liquor in India. Gandhi felt that use of liquor is dangerous to Indian society. Hence Gandhi launched a stubborn campaign against the use of liquor. The Government of Madras Presidency on its part checked the movement by resorting to lathi charge and promul...

  15. Temperature Dependency of Photosynthesis of Sphagnum spp. Distributed in the Warm-Temperate and the Cool-Temperate Mires of Japan

    Directory of Open Access Journals (Sweden)

    Akira Haraguchi

    2011-11-01

    Full Text Available We investigated the temperature dependency of photosynthetic rates for five Sphagnum species: Sphagnum palustre, S. fimbriatum in the Tadewara mire (south-western Japan in a warm-temperate zone and S. papillosum, S. fuscum, S. fallax in the East Ochiishi mire (north-eastern Japan in a cool-temperate zone measuring photosynthetic light response within a temperature range between 5 and 40?C. The maximum photosynthetic rate was obtained at T = 35?C for S. palustre, S. fuscum and S. papillosum, and at T = 30?C for S. fimbriatum and S. fallax. Photosynthetic rates of all these species showed a maximum at 300 - 500 ?mol·m-2·s-1 of PPFD and it decreased at higher PPFD (>500 ?mol·m-2·s-1 under low temperature (5?C - 10?C. These results imply that Sphagnum species are not fully physiologically adapted to low temperature environments, although Sphagnum species distribute mostly in the circumpolar region.

  16. Drivers of long-term variability in CO2 net ecosystem exchange in a temperate peatland

    Science.gov (United States)

    Helfter, C.; Campbell, C.; Dinsmore, K. J.; Drewer, J.; Coyle, M.; Anderson, M.; Skiba, U.; Nemitz, E.; Billett, M. F.; Sutton, M. A.

    2015-03-01

    Land-atmosphere exchange of carbon dioxide (CO2) in peatlands exhibits marked seasonal and inter-annual variability, which subsequently affects the carbon (C) sink strength of catchments across multiple temporal scales. Long-term studies are needed to fully capture the natural variability and therefore identify the key hydrometeorological drivers in the net ecosystem exchange (NEE) of CO2. Since 2002, NEE has been measured continuously by eddy-covariance at Auchencorth Moss, a temperate lowland peatland in central Scotland. Hence this is one of the longest peatland NEE studies to date. For 11 years, the site was a consistent, yet variable, atmospheric CO2 sink ranging from -5.2 to -135.9 g CO2-C m-2 yr-1 (mean of -64.1 ± 33.6 g CO2-C m-2 yr-1). Inter-annual variability in NEE was positively correlated to the length of the growing season. Mean winter air temperature explained 87% of the inter-annual variability in the sink strength of the following summer, indicating an effect of winter climate on local phenology. Ecosystem respiration (Reco) was enhanced by drought, which also depressed gross primary productivity (GPP). The CO2 uptake rate during the growing season was comparable to three other sites with long-term NEE records; however, the emission rate during the dormant season was significantly higher. To summarise, the NEE of the peatland studied is modulated by two dominant factors: - phenology of the plant community, which is driven by winter air temperature and impacts photosynthetic potential and net CO2 uptake during the growing season (colder winters are linked to lower summer NEE), - water table level, which enhanced soil respiration and decreased GPP during dry spells. Although summer dry spells were sporadic during the study period, the positive effects of the current climatic trend towards milder winters on the site's CO2 sink strength could be offset by changes in precipitation patterns especially during the growing season.

  17. Winter Storm Fire Safety

    Science.gov (United States)

    ... a flashlight - not a candle - for emergency lighting. Facebook During a winter storm, smoke alarms dependent on ... get a Student Identification Number . Follow us: Twitter Facebook YouTube U.S. Fire Administration 16825 S. Seton Ave. , Emmitsburg , ...

  18. [Suitability evaluation of great bustard (Otis tarda)'s wintering habitat in Baiyangdian basin].

    Science.gov (United States)

    Zhao, Zhi-xuan; Yan, Deng-hua; Weng, Bai-sha; Zhang, Biao

    2011-07-01

    Based on the related researches of great bustard's wintering habitat selection as well as the advices of related experts and the distribution records of great bustard in Baiyangdian basin, 3 first class indices and 13 second indices were chosen to characterize the key factors affecting the wintering habitat selection of great bustard, and a habitat quality evaluation model was built to assess the quality of wintering habitat selection of great bustard in Baiyangdian basin. In 2005, the suitable wintering habitats of great bustard in the basin had an area of 11907.25 km2, accounting for 34.1% of the total. Of the suitable wintering habitats, the most suitable habitats had an area of 4596.25 km2, only 13.2% of the total and comparatively concentrated in two zones, i.e., Baiyangdian Wetland Natural Reserve and its peripheral area (zone I) in the east of Baiyangdian basin, and Xingtang and Quyang counties (zone II) in the southwest of Baiyangdian basin. The total area of the most suitable habitats in zone I and zone II was 2803.55 km2, accounting for 61.0% of the most suitable habitats in the basin. To protect the wintering habitat of great bustard in the basin, proper measures should be taken according to the environmental features of the two zones. PMID:22007472

  19. Evolution of cold-tolerant fungal symbionts permits winter fungiculture by leafcutter ants at the northern frontier of a tropical ant–fungus symbiosis

    OpenAIRE

    Ulrich G. Mueller; Mikheyev, Alexander S.; Hong, Eunki; Sen, Ruchira; Dan L. Warren; Scott E. Solomon; Ishak, Heather D.; Cooper, Mike; Miller, Jessica L.; Shaffer, Kimberly A.; Juenger, Thomas E

    2011-01-01

    The obligate mutualism between leafcutter ants and their Attamyces fungi originated 8 to 12 million years ago in the tropics, but extends today also into temperate regions in South and North America. The northernmost leafcutter ant Atta texana sustains fungiculture during winter temperatures that would harm the cold-sensitive Attamyces cultivars of tropical leafcutter ants. Cold-tolerance of Attamyces cultivars increases with winter harshness along a south-to-north temperature gradient across...

  20. Science of Winter

    Science.gov (United States)

    Is it true that no two snowflakes are alike? What happens to mosquitoes when the mercury drops? National Geographic Channel explores the planet's most extreme season. This engaging three-minute video discusses the astronomical basis for winter, and other seasons, based on the angle of incidence of the sun's rays relative to the Northern and Southern Hemispheres, as well as the components of intense winter storms.

  1. Warmest winter in history

    Science.gov (United States)

    Payne, Laura X.

    For four days last week, the daily temperatures outside the Internet Scout Project office here in Wisconsin soared above 60 F (and on one day, above 75 F), and the lakes that surround Madison melted in one fell swoop, bringing winter to a lurching halt and restless thoughts of summer to the forefront. While such local temperature anomalies are not surprising (nor did other cities experience the same highs), in this case, they fit in with a global trend that continues to raise -- in some cases, anxious -- eyebrows. On Friday, the National Oceanic and Atmospheric Administration (NOAA) announced that this winter is the warmest on record. Surpassing recent warm winter records of 1997-1998, the winter of 1999-2000 has now clinched the somewhat dubious title of warmest winter in history. This news release comes on the coat tails of a January report from the National Academy of Sciences confirming what is already accepted among most scientists -- that global warming is real (see the January 14, 2000 Scout Report). For news and information on this warmest of winters, this week's In The News features seven sites, listed above.

  2. Control of weldability : Research leading to the development of two new quenched and tempered tool steels

    OpenAIRE

    Hansson, Per

    2004-01-01

    The understanding of the hardenability is important in steel development with respect to weldability of steels as well as to the design of quenched and tempered steels.The common way to judge if steel is suitability to welding is the use of a carbon equivalent, which reflects the alloy content to the hardenability of the heat affected zone (HAZ). Most common of these equivalent is the IIW carbon equivalent wich has been in use for decades. However, this is an empirical equivalent, developed f...

  3. CO2 flux in a cool-temperate deciduous forest (Quercus mongolica) of Mt. Nam in Seoul, Korea

    OpenAIRE

    Seung Jin Joo; Moon-Soo Park; Gyung Soon Kim; Chang Seok Lee

    2011-01-01

    The Namsan Ecological Tower Site based on a flux tower was equipped with eddy covariance and automatic opening/closing chamber systems to collect long-term continuous measurements of CO2 flux, such as the net ecosystem exchange(NEE) and soil CO2 efflux in a cool-temperate Quercus mongolica forest. The mean concentrations of atmosphericCO2 (705 mg/m3) during the summer were smaller than those measured (770 mg/m3) during the winter. The mean CO2flux during the summer period was negative (-0.34 ...

  4. Dead Zones

    Science.gov (United States)

    The Earth currently has more than 400 "dead zones"--marine expanses covering hundreds, or even thousands, of square miles that periodically become virtually lifeless. Explore the surprising causes of Oregon's dead zones, and the pioneering methods used to research them.

  5. Comportamiento de vacas Holstein mantenidas en un sistema de estabulación libre, en invierno, en zona árida, México Behaviour of Holstein cows under a free housing system, in winter, in an arid zone, México

    Directory of Open Access Journals (Sweden)

    I. Vitela

    2005-01-01

    Full Text Available El objetivo de esta investigación fue evaluar el comportamiento individual y social de vacas lecheras bajo un sistema de estabulación libre durante el invierno y entre períodos de alimentación. El estudio se realizó durante 60 días en un hato productor de leche en el Estado de Aguascalientes, México, con 40 vacas Holstein en producción de entre 2 a 4 años de edad. Las vacas estaban en un solo corral y con un espacio de 40 m²/vaca. Los resultados mostraron que las vacas destinaron 51% del tiempo en descansar echadas, 29% para rumiar, 10% para comer, 4% para caminar, 4% permanecieron paradas, y 2% para colear; no hubo conductas de sacudidas (movimiento costal, orejear, cabecear y patear. Para conductas sociales se observó una frecuencia de interacciones afiliativas de 6,1/hora, y 0,95/hora de interacciones agresivas; dentro de las conductas afiliativas emitidas a otras vacas se identificó una frecuencia para lamer de 4,9/hora, oler de 0,61/hora, recargarse de 0,24/ hora, montar de 0,18/hora y rascarse de 0,12/hora; dentro de las conductas agresivas se identificaron las de seguir, amenazar y topetear a otras vacas con valores de 0,63/hora, 0,10/hora y 0,22/hora, respectivamente. Las vacas presentaron conductas de mantenimiento y sociales que sugieren un estado de bienestar, atribuible a la temperatura ambiente predominante en la época de estudio, el espacio individual asignado a cada animal y al horario en que se registraron las conductas.The objective of this trial was to assess the social and individual behaviour of dairy cows under free housing conditions, during a winter season and between feeding periods. The study considered 60 days of observations using 40 Holstein cows (2-4 years old from a dairy herd in the state of Aguascalientes. The cows were all kept in one pen with a space allowance of 40m²/cow. Individual behaviour data showed that cows spent 51% of their time resting in a lying position, 29% ruminating, 10% eating, 4% walking, 4% standing and 2% tail switching. No evidence of body quivering, ear twitching, head tossing or kicking was found. Social behaviour data showed that affiliation interactions occurred 6.1 times per hour and aggressive interactions 0.95 times per hour. Regarding affiliation behaviour it was found that licking, smelling, replenishing, mounting and scratching other cows occurred 4.9/hour, 0.61/hour, 0.24/hour, 0.18/hour and 0.12/hour respectively. Regarding aggressive behaviour the following was recorded: cows following, threatening and butting other cows occurred 0.63/hour, 0.10/hour and 0.22/hour respectively. The cows showed maintenance and social behaviours that suggest a welfare state attributable to the environmental temperature that was predominant during the season of study, the individual space assigned per cow and the time schedule in which the observations were made.

  6. Methane Metabolism in a Temperate Swamp

    OpenAIRE

    Amaral, J. A.; Knowles, R

    1994-01-01

    Comparisons between in situ CH4 concentration and potential factors controlling its net production were made in a temperate swamp. Seasonal measurements of water table level and depth profiles of pH, dissolved CH4, CO2, O2, SO42-, NO3-, formate, acetate, propionate, and butyrate were made at two adjacent sites 1.5 to 2 m apart. Dissolved CH4 was inversely correlated to O2 and, in general, to NO3- and SO42-, potential inhibitors of methanogenesis. At low water table levels (August 1992), maxim...

  7. Value at Risk with tempered multistable motions

    OpenAIRE

    El Mekeddem, Hicham; Le?vy Ve?hel, Jacques

    2013-01-01

    This is an empirical work showing numerically the importance of taking into account non-stationarities in CGMY and similar models for computing VaRs. More precisely we model S&P 500 logs with a CGMY model, but where the parameters are allowed to vary. We show that C, G, M and Y in- deed display significant variations across time. Most relevant is the variation of Y , which implies that the correct modelling frame is the one of tempered multistable motions, a recently introduced class of stoch...

  8. Adhesion and wear properties of boro-tempered ductile iron

    International Nuclear Information System (INIS)

    Highlights: ? In this study, the wear and adhesion properties of BDI were investigated. ? Boro-tempering process under several heat treatment conditions was examined. ? Optical microscope, SEM and XRD analysis were carried out to investigate the microstructure. ? It was observed that boro-tempering process improves micro-hardness and wear properties of ductile irons. -- Abstract: In this study, adhesion and wear properties of boro-tempered ductile iron (BDI) were investigated. Boro-tempering was carried out on two stage processes i.e. boronizing and tempering. At the first stage, ductile iron samples were boronized by using pack process at 900 oC for 1, 3, and 5 h and then, secondly tempered at 250, 300, 350, and 400 oC for 1 h. X-ray diffraction (XRD) analysis of boro-tempered samples showed that FeB and Fe2B phases were found on the surface of the samples. The Daimler-Benz Rockwell-C adhesion test was used to assess the adhesion of boride layer. Test result showed that adhesion decreased with increasing boriding time and increased with increasing tempering temperature. Dry sliding wear tests of these samples were performed against Al2O3 ball at a constant sliding speed and loads of 5 and 10 N. Wear tests indicated that boro-tempering heat treatment increased wear resistance of ductile iron. In addition, it was found that while wear rate of boro-tempered samples decreased with increasing boriding time, there is no significant affect of tempering temperature on wear rate.

  9. Seasonal in situ observations of glyoxal and methylglyoxal over the temperate oceans of the Southern Hemisphere

    Directory of Open Access Journals (Sweden)

    S. J. Lawson

    2014-08-01

    Full Text Available Dicarbonyls glyoxal and methylglyoxal have been measured with 2,4-dinitrophenylhydrazine (2,4-DNPH cartridges and high performance liquid chromatography (HPLC, optimised for dicarbonyl detection, in clean marine air over the temperate Southern Hemisphere (SH oceans. Measurements of a range of dicarbonyl precursors (volatile organic compounds, VOCs were made in parallel. These are the first in situ measurements of glyoxal and methylglyoxal over the remote temperate oceans. Six 24 h samples were collected in late summer (February–March over the Chatham Rise in the South West Pacific Ocean during the Surface Ocean Aerosol Production (SOAP voyage in 2012, while 34 24 h samples were collected at Cape Grim Baseline Air Pollution Station in late winter (August–September 2011. Average glyoxal mixing ratios in clean marine air were 7 ppt at Cape Grim, and 24 ppt over Chatham Rise. Average methylglyoxal mixing ratios in clean marine air were 28 ppt at Cape Grim and 12 ppt over Chatham Rise. The mixing ratios of glyoxal at Cape Grim are the lowest observed over the remote oceans, while mixing ratios over Chatham Rise are in good agreement with other temperate and tropical observations, including concurrent MAX-DOAS observations. Methylglyoxal mixing ratios at both sites are comparable to the only other marine methylglyoxal observations available over the tropical Northern Hemisphere (NH ocean. Ratios of glyoxal : methylglyoxal > 1 over Chatham Rise but 14 molecules cm?2 at both sites. This discrepancy may be due to the incorrect assumption that all glyoxal observed by satellite is within the boundary layer, or may be due to challenges retrieving low VCDs of glyoxal over the oceans due to interferences by liquid water absorption, or use of an inappropriate normalisation reference value in the retrieval algorithm. This study provides much needed data to verify the presence of these short lived gases over the remote ocean and provide further evidence of an as yet unidentified source of both glyoxal and also methylglyoxal over the remote oceans.

  10. Tempering characteristics of a vanadium containing dual phase steel

    Science.gov (United States)

    Rashid, M. S.; Rao, B. V. N.

    1982-10-01

    Dual phase steels are characterized by a microstructure consisting of ferrite, martensite, retained austenite, and/or lower bainite. This microstructure can be altered by tempering with accompanying changes in mechanical properties. This paper examines such changes produced in a vanadium bearing dual phase steel upon tempering below 500 °C. The steel mechanical properties were minimally affected on tempering below 200 °C; however, a simultaneous reduction in uniform elongation and tensile strength occurred upon tempering above 400 °C. The large amount of retained austenite (?10 vol pct) observed in the as-received steel was found to be essentially stable to tempering below 300 °C. On tempering above 400 °C, most of the retained austenite decomposed to either upper bainite (at 400 °C) or a mixture of upper bainite and ferrite-carbide aggregate formed by an interphase precipitation mechanism (at 500 °C). In addition, tempering at 400 °C led to fine precipitation in the retained ferrite. The observed mechanical properties were correlated with these microstructural changes. It was concluded that the observed decrease in uniform elongation upon tempering above 400 °C is primarily the consequence of the decomposition of retained austenite and the resulting loss of transformation induced plasticity (TRIP) as a contributing mechanism to the strain hardening of the steel.

  11. Temperance: With a Consideration of Evil, Violence, and Pedagogy

    Science.gov (United States)

    Felderhof, Marius C.

    2009-01-01

    The article investigates the meaning of temperance by noting some cultural assumptions, raising the question as to why this classical virtue has largely disappeared from modern ethical discourse. By means of some historical notes temperance is identified as the unifying virtue in the person and in society. In its Christian form it is related to…

  12. a Climatology of Extreme Minimum Winter Temperatures in Ohio

    Science.gov (United States)

    Edgell, Dennis Joe

    The Extreme Minimum Winter Temperature (EMWT) is the coldest temperature recorded each winter at a given weather station. This variable is a measure of winter temperature stress. Extreme cold influences the geographic distribution of plants, and is a prime control for the production of some valuable fruit crops grown in Ohio. EMWT values are often used to map plant hardiness zones, however the magnitude of EMWT and the date that it occurs has varied widely from year to year. Climatic variables rarely remain constant over time, and the plant hardiness zones could shift significantly if the climate changes and there is a trend towards warmer EMWTs. Plants that have their present geographic ranges limited by cold winter temperatures could increase their spatial extent. Furthermore, EMWT has impacts on human health and has applications for architecture. EMWTs at eighty-nine weather stations in Ohio were analyzed. Summary statistics and return period intervals for critical EMWTs are tabulated and mapped. Return period maps may be more useful for environmental planning than plant hardiness zone maps based on average EMWT, especially in a variable climate. Graphical methods, curve fitting and a probability model for the mean were utilized to examine the long term trend. The EMWT has not warmed during the known climatic record of this variable in Ohio. This study demonstrates the need for more applied climatological studies based on the observed climate record, not obscured by the assumptions of the global warming paradigm.

  13. Effects of tempering on internal friction of carbon steels

    International Nuclear Information System (INIS)

    Research highlights: ? Time tempering dependent microstructure of two steels is studied by internal friction. ? Internal friction indicates the interactions of dislocations with carbon and carbides. ? Internal friction detects the first stage of tempering. ? Precipitation hardening is detected by the decrease in the background. - Abstract: Two steels containing 0.626 and 0.71 wt.% carbon have been studied to determine the effects of tempering on the microstructure and the internal friction. The steels were annealed at 1093 K, quenched into water and tempered for 60 min at 423 K, 573 K and 723 K. The increase of the tempering time diminishes the martensite tetragonality due to the redistribution of carbon atoms from octahedrical interstitial sites to dislocations. Internal friction spectrum is decomposed into five peaks and an exponential background, which are attributed to the carbide precipitation and the dislocation relaxation process. Simultaneous presence of peaks P1 and P2 indicates the interaction of dislocations with the segregated carbon and carbide precipitate.

  14. Winter Playscape Dreaming

    Science.gov (United States)

    Keeler, Rusty

    2006-01-01

    Winter, like all seasons, adds a new sense of mystery and discovery to the world of young children. It is the time when they can study snowflakes, find icicles, or observe the birds that share their yards. This article presents ideas and suggestions on how to plan a playscape. A playscape is a man-made seasonal playground for young children. It…

  15. Teaching Ecology in Winter.

    Science.gov (United States)

    Clearing: Nature and Learning in the Pacific Northwest, 1984

    1984-01-01

    Presents ideas for teaching ecology in the winter. Suggested topic areas or units include snow insulation and density, snowflakes and snow crystals, goldenrod galls, bird behavior, survival techniques, bacteriology and decomposition, trees and keying, biomass and productivity, pollution, and soil organisms. A sample student activity sheet is…

  16. Seasonal in situ observations of glyoxal and methylglyoxal over the temperate oceans of the Southern Hemisphere

    Science.gov (United States)

    Lawson, S. J.; Selleck, P. W.; Galbally, I. E.; Keywood, M. D.; Harvey, M. J.; Lerot, C.; Helmig, D.; Ristovski, Z.

    2015-01-01

    The dicarbonyls glyoxal and methylglyoxal have been measured with 2,4-dinitrophenylhydrazine (2,4-DNPH) cartridges and high-performance liquid chromatography (HPLC), optimised for dicarbonyl detection, in clean marine air over the temperate Southern Hemisphere (SH) oceans. Measurements of a range of dicarbonyl precursors (volatile organic compounds, VOCs) were made in parallel. These are the first in situ measurements of glyoxal and methylglyoxal over the remote temperate oceans. Six 24 h samples were collected in summer (February-March) over the Chatham Rise in the south-west Pacific Ocean during the Surface Ocean Aerosol Production (SOAP) voyage in 2012, while 34 24 h samples were collected at Cape Grim Baseline Air Pollution Station in the late winter (August-September) of 2011. Average glyoxal mixing ratios in clean marine air were 7 ppt at Cape Grim and 23 ppt over Chatham Rise. Average methylglyoxal mixing ratios in clean marine air were 28 ppt at Cape Grim and 10 ppt over Chatham Rise. The mixing ratios of glyoxal at Cape Grim are the lowest observed over the remote oceans, while mixing ratios over Chatham Rise are in good agreement with other temperate and tropical observations, including concurrent Multi-Axis Differential Optical Absorption Spectroscopy (MAX-DOAS) observations. Methylglyoxal mixing ratios at both sites are comparable to the only other marine methylglyoxal observations available over the tropical Northern Hemisphere (NH) ocean. Ratios of glyoxal : methylglyoxal > 1 over Chatham Rise but marine boundary layer and explain at most 1-3 ppt of dicarbonyls observed, corresponding to 10% and 17% of the observed glyoxal and 29 and 10% of the methylglyoxal at Chatham Rise and Cape Grim, respectively, highlighting a significant but as yet unknown production mechanism. Surface-level glyoxal observations from both sites were converted to vertical columns and compared to average vertical column densities (VCDs) from GOME-2 satellite retrievals. Both satellite columns and in situ observations are higher in summer than winter; however, satellite vertical column densities exceeded the surface observations by more than 1.5 × 1014 molecules cm-2 at both sites. This discrepancy may be due to the incorrect assumption that all glyoxal observed by satellite is within the boundary layer, or it may be due to challenges retrieving low VCDs of glyoxal over the oceans due to interferences by liquid water absorption or the use of an inappropriate normalisation reference value in the retrieval algorithm. This study provides much-needed data to verify the presence of these short-lived gases over the remote ocean and provide further evidence of an as yet unidentified source of both glyoxal and also methylglyoxal over the remote oceans.

  17. Sensing winter soil respiration dynamics in near-real time

    Science.gov (United States)

    Contosta, A.; Burakowski, E. A.; Varner, R. K.; Frey, S. D.

    2014-12-01

    Some of the largest reductions in seasonal snow cover are projected to occur in temperate latitudes. Limited measurements from these ecosystems indicate that winter soil respiration releases as much as 30% of carbon fixed during the previous growing season. This respiration is possible with a snowpack that insulates soil from ambient fluctuations in climate. However, relationships among snowpack, soil temperature, soil moisture, and winter soil respiration in temperate regions are not well-understood. Most studies have infrequently sampled soil respiration and its drivers, and most measurements have been limited to the soil surface. We made near-real time, continuous measurements of temperature, moisture, and CO2 fluxes from the soil profile, through the snowpack, and into the atmosphere in a deciduous forest of New Hampshire, USA. We coupled these data with daily sampling of snow depth and snow water equivalent (SWE). Our objectives were to continuously measure soil CO2 production (Psoil) and CO2 flux through the snowpack (Fsnow) and to compare Fsnow and Psoil with environmental drivers. We found that Fsnow was more dynamic than Psoil, changing as much as 30% over several days with shifting environmental conditions. Multiple regression indicated that SWE, air temperature, surface soil temperature, surface soil CO2 concentrations, and soil moisture at 15 cm were significant predictors of Fsnow. The transition of surface temperature from below to above 0°C was particularly important as it represented a phase change from ice to liquid water. Only air temperature and soil moisture at 15 cm were significant drivers of Psoil, where higher moisture at 15 cm resulted in lower Psoil rates. Time series analysis showed that Fsnow lagged 40 days behind Psoil. This lag may be due to slow CO2 diffusion through soil to overlying snow under high moisture conditions. Our results suggest that surface soil CO2 losses are driven by rapid changes in snow cover, surface temperature, and surface moisture while winter soil CO2 production is driven by subsurface moisture conditions. Our finding that subsurface moisture regulated winter soil respiration demonstrates the transformative power of sensors; winter measurements of soil CO2 concentrations and moisture levels would not be possible with traditional methods.

  18. Exponentially tempered lévy sums in random lasers.

    Science.gov (United States)

    Uppu, Ravitej; Mujumdar, Sushil

    2015-05-01

    Lévy fluctuations have associated infinities due to diverging moments, a problem that is circumvented by putting restrictions on the magnitude of the fluctuations, realizing a process called the truncated Lévy flight. We show that a perfect manifestation of this exotic process occurs in coherent random lasers, and it turns out to be the single underlying explanation for the complete statistical behavior of nonresonant random lasers. A rigorous parameter estimation of the number of summand variables, the truncation parameter, and the power-law exponent is carried out over a wide range of randomness, inversion, and system size. Random laser intensity is modeled on a unique platform of exponentially tempered Lévy sums. The computed behavior exhibits an excellent agreement with the experimentally observed fluctuation behavior. PMID:26001004

  19. TEMPERANCE MOVEMENT IN TAMILNADU, 1930-1934

    Directory of Open Access Journals (Sweden)

    A. Kasthuri

    2014-08-01

    Full Text Available The Civil Disobedience Movement made its appearance in the country In March 1930. One of the major off shoots was temperance movement. The purpose of the movement was to cripple the revenue to the British by the sale of liquor in India. Gandhi felt that use of liquor is dangerous to Indian society. Hence Gandhi launched a stubborn campaign against the use of liquor. The Government of Madras Presidency on its part checked the movement by resorting to lathi charge and promulgating several ordinances one after another during 1930-34. This paper tries to account all the details which occurred relating to the movement during the period of 1930-34.

  20. Temperate Ice Depth-Sounding Radar

    Science.gov (United States)

    Jara-Olivares, V. A.; Player, K.; Rodriguez-Morales, F.; Gogineni, P.

    2008-12-01

    Glaciers in several parts of the world are reported to be retreating and thinning rapidly over the last decade. Radar instruments can be used to provide a wealth of information regarding the internal and basal conditions of large and small ice masses. These instruments typically operate in the VHF and UHF regions of the electromagnetic spectrum. For temperate-ice sounding, however, the high water content produces scattering and attenuation in propagating radar waves at VHF and UHF frequencies, which significantly reduce the penetration depths. Radars operating in the HF band are better suited for systematic surveys of the thickness and sub-glacial topography of temperate-ice regions. We are developing a dual-frequency Temperate-Ice-Depth Sounding Radar (TIDSoR) that can penetrate through water pockets, thus providing more accurate measurements of temperate ice properties such as thickness and basal conditions. The radar is a light-weight, low power consumption portable system for surface-based observations in mountainous terrain or aerial surveys. TIDSoR operates at two different center frequencies: 7.7 MHz and 14 MHz, with a maximum output peak power of 20 W. The transmit waveform is a digitally generated linear frequency-modulated chirp with 1 MHz bandwidth. The radar can be installed on aircrafts such as the CReSIS UAV [1], DCH-6 (Twin Otter), or P-3 Orion for aerial surveys, where it could be supported by the airplane power system. For surface based experiments, TIDSoR can operate in a backpack configuration powered by a compact battery system. The system can also be installed on a sled towed by a motorized vehicle, in which case the power supply can be replaced by a diesel generator. The radar consists of three functional blocks: the digital section, the radio-frequency (RF) section, and the antenna, and is designed to weigh less than 2 kg, excluding the power supply. The digital section generates the transmit waveforms as well as timing and control signals. It also digitizes the output signal from the receiver and stores the data in binary format using a portable computer. The RF-section consists of a high- power transmitter and a low-noise receiver with digitally controlled variable gain. The antenna is time-shared between the transmitter and receiver by means of a transmit/receive (T/R) switch. In regards to the antenna, we have made a survey study of various electrically small antennas (ESA) to choose the most suitable radiating structure for this application. Among the different alternatives that provide a good trade-off between electrical performance and small size, we have adopted an ESA dipole configuration for airborne platforms and a half-wavelength radiator for the surface-based version. The airborne antenna solution is given after studying the geometry of the aerial vehicle and its fuselage contribution to the antenna radiation pattern. Dipoles are made of 11.6 mm diameter cables (AWG 0000) or printed patches embedded into the aircraft fuselage, wings, or both. The system is currently being integrated and tested. TIDSoR is expected to be deployed during the spring 2008 either in Alaska or Greenland for surface based observations. In this paper, we will discuss our design considerations and current progress towards the development of this radar system. [1] Center for Remote Sensing of Ice Sheets (Cresis), Sept 2008, [Online]. Available: http://www.cresis.ku.edu

  1. Numerical investigation of a novel connection in tempered glass using holes drilled after tempering

    DEFF Research Database (Denmark)

    Nielsen, Jens Henrik

    2013-01-01

    This paper is a continuation of a previous paper [Nielsen, 2012] where the influ-ence on the temper stresses by drilling into tempered glass was investigated. In [Nielsen, 2012] it was shown that partly drilled holes in tempered glass would lead to higher compressive resid-ual hoop stresses at the hole increasing the apparent strength. Utilizing this for joints, raises new questions like the concentration of stresses arising at the hole for external loading of the pin and the glass. The present paper numerically investigates the shear load transfer for a specific configuration of the pin, the hole and the adhesive. In the paper a short discussion of the change in residual stresses due to the drilling and a FE-model for the loading of the pin in the hole is developed. From this model, the stress state occurring in such joints is investigated assuming both elastic and ideal plastic behaviour of the adhesive. Based on the numerical results, a proposal for an op-timal configuration using multiple pins is given.

  2. Hardness, Microstructure, and Residual Stresses in Low Carbon Steel Welding with Post-weld Heat Treatment and Temper Bead Welding

    Science.gov (United States)

    Aloraier, Abdulkareem S.; Joshi, Suraj; Price, John W. H.; Alawadhi, Khaled

    2014-04-01

    This paper investigates the effects of post-weld heat treatment (PWHT) and temper bead welding (TBW) on hardness, microstructure and residual stresses in multi-layer welding on low carbon steel specimens made with two different weld geometries, viz. (1) smooth-contoured and (2) U-shaped. It was found that the PWHT technique gave overall lower hardness than the TBW technique, but the hardness values in both techniques were acceptable. Microscopy analysis showed that the TBW technique was more effective in tempering the heat affected zone as the grain size decreased slightly at the fusion line in spite of the higher temperature at the fusion line. Residual stresses measured using the hole-drilling method showed that the residual stress is not reduced below yield stress near the last bead solidified in TBW. Only PWHT gives low residual stress results in this area. High tensile residual stresses may result in sensitivity to fatigue loading.

  3. Uptake and resource allocation of ammonium and nitrate in temperate seagrasses Posidonia and Amphibolis

    International Nuclear Information System (INIS)

    Ecologically relevant estimates of seasonal variability in nitrogen uptake and allocation in two species of temperate seagrasses were obtained using in situ isotope-labelling approach. Significantly higher uptake rates of ammonium by leaves, roots and epiphytes of Amphibolis than Posidonia were observed. Overall, root uptake rates were lower than other components. Effect of season was not significant for leaves, roots or epiphytes of the two species. However, plankton uptake varied seasonally with higher rates in winter (0.98 mg N g-1 DW h-1). In contrast, nitrate uptake rates for various components were significantly affected by seasons. Uptake rates by plankton were highest ranging from 0.003 mg N g-1 DW h-1 (summer, Amphibolis) to 0.69 mg N g-1 DW h-1 (winter, Posidonia). Uptake of nitrate by roots was negligible. Biotic uptake rates for nitrate were an order of magnitude slower than ammonium, demonstrating an affinity for ammonium over nitrate as a preferred inorganic nitrogen source. Adelaide coastal waters have lost over 5000 ha of seagrasses, much of this attributed to nutrient inputs from wastewater, industrial and stormwater. Managing these inputs into future requires better understanding of the fate of nutrients, particularly biological uptake. This study attempts to quantify uptake rates of nitrogen by seagrasses.

  4. Dead Zone

    Science.gov (United States)

    2010-08-31

    In this video segment adapted from the independent film Big River: A King Corn Companion, the filmmakers explain how agricultural runoff from the Midwest has contributed to a massive "dead zone" in the Gulf of Mexico. A cornfield treated with conventional chemical fertilizer promises a bumper crop, but chemical runoff from the farm enters the Iowa River, eventually draining into the Mississippi River and the Gulf of Mexico. In the Gulf, these dissolved nutrients allow algae to flourish. The algae's decay depletes the water of oxygen, creating a dead zone where shrimp and fish are starved of oxygen and die. A background essay, discussion questions, and standards correlations are also provided.

  5. Editorial - The winter Atomiades

    CERN Multimedia

    Staff Association

    2011-01-01

    As we wrote in our previous editorial, the Staff Association gives direct support to sports events, such as the Atomiades, a section of the Association of Sports Communities of European Research Institutes, which brings together sportsmen and women from 38 European research centres in 13 countries (Austria, Belgium, Czech Republic, United Kingdom, Finland, France, Germany, Hungary, Italy, Luxemburg, the Netherlands, Russia, and Switzerland). The summer Atomiades take place between the months of June and September every three years. Thirteen such events have taken place since 1973, the last one in June 2009 in Berlin. As far as the winter Atomiades are concerned, also organized every three years, and alternating with the summer Atomiades, there have been eleven since 1981, the last one at the end of January this year in neighbouring France. The following article tells the wonderful adventure of the CERN staff who took part in this event. A positive outcome for CERN skiers at the winter Atomiades The 11t...

  6. Winter School Les Houches

    CERN Document Server

    Lannoo, Michel; Bastard, Gérald; Voos, Michel; Boccara, Nino

    1986-01-01

    The Winter School held in Les Houches on March 12-21, 1985 was devoted to Semiconductor Heterojunctions and Superlattices, a topic which is recognized as being now one of the most interesting and active fields in semiconductor physics. In fact, following the pioneering work of Esaki and Tsu in 1970, the study of these two-dimensional semiconductor heterostructures has developed rapidly, both from the point of view of basic physics and of applications. For instance, modulation-doped heterojunctions are nowadays currently used to investigate the quantum Hall effect and to make very fast transistors. This book contains the lectures presented at this Winter School, showing in particular that many aspects of semiconductor heterojunctions and super­ lattices were treated, extending from the fabrication of these two-dimensional systems to their basic properties and applications in micro-and opto-electron­ ics. Among the subjects which were covered, one can quote as examples: molecular beam epitaxy and metallorgani...

  7. Postponed reproduction as an adaptation to winter conditions in Drosophila melanogaster: evidence for clinal variation under semi-natural conditions.

    OpenAIRE

    Mitrovski, P; A. A. Hoffmann

    2001-01-01

    Patterns of climatic adaptation in drosophila and other insects have largely been inferred from laboratory comparisons of traits that vary clinally. Here, we extend this research to comparisons under semi-natural conditions. To test for clinal variation in reproductive patterns and survival over winter, Drosophila melanogaster populations were initiated from seven collection sites along the eastern coast of Australia, ranging from tropical to temperate regions. The fecundity and survival of t...

  8. Magnetic nondestructive technology for detection of tempered martensite embrittlement

    International Nuclear Information System (INIS)

    A nondestructive eddy current technique is used to evaluate tempered martensite embrittlement in 4340 AISI steels after quench and tempering in the range 240–550 °C. A relation between the responses of the magnetic induction (normalized impedance of the coil) and destructive Charpy impact test results has been established. The study shows that the eddy current method could be used to separate brittle parts due to the microstructure changes. - Highlights: ? Occurrence of tempered martensite embrittlement in 4340 AISI steels was evaluated. ? A reliable relation between EC output and Charpy impact test results was obtained. ? EC technique was used to separate brittle parts due to the microstructure changes.

  9. Non destructive evaluation of temper embrittlement of martensitic stainless steel

    International Nuclear Information System (INIS)

    Martensitic stainless steel SS403, a sub set of SS410, is widely used as fuel-channel end-fitting material in Pressurized Heavy Water Reactor (PHWR). This material is selected because of its high corrosion resistance (the design utilizes several critical seal faces), good mechanical properties (optimum combination of strength, toughness and hardness for leak- tight roll joint), matching thermal coefficient of expansion with zirconium alloys (to minimize thermal stresses at rolled joint) and resistance to irradiation induced damages .The steel is produced by the electric arc furnace process and is subjected to vacuum degassing and electro-slag refining (ESR). The material is used in quenched and tempered condition. The end product should have at least 27 J minimum (Longitudinal) Charpy V-Notch (CVN) impact value at 21 deg C and 20J minimum (Transverse) CVN impact value at 65 deg C. In Martensitic Stainless Steel, a wide range of mechanical properties can be obtained by varying the tempering temperature and time . As tempering temperature is increased or time at particular temperature is prolonged, tensile strength, yield strength and hardness decrease; and impact strength, elongation, and reduction in area increase. The most uniform hardness is attained by close control of temperature, especially when tempering at lower temperatures. The tempering temperature depends primarily on the properties desired. Like most alloy steels, the hardenable stainless steels also develthe hardenable stainless steels also develop lower impact strength when tempered in the range from about 250 deg C to 550 deg C. Tempering at lower side of the range results in tempered martensite embrittlement (TME) whereas aging at temperature near 450-550 deg C results in temper embrittlement (TE). Temper embrittlement is caused by segregation of impurity elements mainly S, P. Si, Sn, As, Sb, and P at prior austenite grain boundaries. Under loading it causes de-cohesion along the grain boundaries leading to intergranular failure. Whereas TME is not related to the segregation phenomena and failure is transgranular with respect to prior austenite grain boundary. Magnitude of embrittlement is significantly greater in material which contain higher amount of retained austenite. Explanations of TME are linked to the coarsening of inter-lath cementite formed from decomposition of retained austenite during tempering. The embrittlement manifests as degradation in CVN impact properties namely viz, reduction in upper shelf energy (USE) or increase in ductile-brittle transition temperature (DBTT). As a result, tempering of this steel is generally confined to the range of 590 deg C to 750 deg C. (author)

  10. Winter maintenance and cycleways

    OpenAIRE

    Bergstro?m, Anna

    2002-01-01

    Increasing cycling as a means of personal travel couldgenerate environmental benefits if associated with acorresponding decrease in car-based transport. In seeking topromote cycling in wintertime, it is desirable to understandhow important the road surface condition is compared to otherfactors in people's decision to cycle or not. In this thesis,the possibility of increasing the number of cyclists byimproving the winter maintenance servicelevel on cycleways isexamined. The attitudes towards c...

  11. Geometry of Winter Model

    CERN Document Server

    Aglietti, U G

    2015-01-01

    By constructing the Riemann surface controlling the resonance structure of Winter model, we determine the limitations of perturbation theory. We then derive explicit non-perturbative results for various observables in the weak-coupling regime, in which the model has an infinite tower of long-lived resonant states. The problem of constructing proper initial wavefunctions coupled to single excitations of the model is also treated within perturbative and non-perturbative methods.

  12. Neural network prediction of hardness in HAZ of temper bead welding using the proposed thermal cycle tempering parameter (TCTP)

    International Nuclear Information System (INIS)

    A new thermal cycle tempering parameter (TCTP) to characterize the tempering effect during multi-pass thermal cycles has been proposed by extending the Larson-Miller parameter (LMP) to non-isothermal heat treatment. Experimental results revealed that the hardness in synthetic HAZ of low-alloy steel subjected to multi-pass tempering thermal cycles has a good linear relationship with the TCTP. The new hardness prediction system was constructed by using a neural network taking into consideration of the tempering effect during multi-pass welding, estimated by using the TCTP. Based on the thermal cycles numerically obtained by FEM and the experimentally obtained hardness database, the hardness distribution in HAZ of low-alloy steel welded with temper bead welding method was calculated. The predicted hardness was in good accordance with the experimental results. It follows that our new prediction system is effective for estimating the tempering effect in HAZ during multi-pass welding and hence enables us to assess the effectiveness of temper bead welding. (author)

  13. Estimación de la disponibilidad de frío invernal para cerezos de la zona norte de la provincia de Mendoza, Argentina / Winter chill availability estimation for sweet cherries in northern Mendoza province, Argentina

    Scientific Electronic Library Online (English)

    G., Naranjo; E., Tersoglio.

    2010-06-01

    Full Text Available Durante el reposo invernal los frutales de clima templado deben estar expuestos a bajas temperaturas para satisfacer sus necesidades de frío. La disponibilidad de frío varía entre regiones y entre años, y puede ser insuficiente para los cerezos. Por lo tanto cuando se desea incorporar el cultivo del [...] cerezo a nuevas regiones se debe conocer previamente la disponibilidad de frío invernal. Los objetivos del presente estudio fueron: desarrollar un pronóstico para estimar la disponibilidad de frío invernal y calcular la probabilidad de satisfacer una determinada demanda de frío del año en curso. Los modelos mostraron que el porcentaje de variabilidad explicado de las unidades de frío Utah modificado en las fechas de referencias (UFUM FR) varía entre 50 y 87% para Junín y entre 50 y 86% para San Martín. La probabilidad que posee Junín de alcanzar el valor medio de 884 unidades de frío Utah Modificado (UFUM) es 28%, mientras el valor medio de San Martín es 816 UFUM y su probabilidad es 16%. El pronóstico de frío invernal permitirá al productor evaluar los riesgos que posee su plantación de experimentar daños por falta de frío invernal y eventualmente ejecutar medidas correctivas. Abstract in english During the winter rest, fruit trees of temperate zones should be exposed to low temperatures in order to satisfy their chilling requirements. Chill availability varies through regions and years, and this may be insufficient for cherry trees. Therefore, when farmers want to incorporate new areas, the [...] y should be acquainted with winter chilling availability beforehand. The objectives of this study were: to develop a prognosis to estimate the amount of winter chilling and to calculate the probability of satisfying the amount of chilling requirement of any given year. Models showed that the proportion explained by modified Utah chill units at reference date (MUCU RD) varied between 50 to 87% for Junín and 50 to 86% for San Martín. For Junín, the probability to reach an average value of 884 chill units Utah modified (MUCU) is 28%, whereas the average value for San Martín is 816 MUCU and its probability correspond to 16%. The winter chill prognosis will allow the producer evaluates the risks which has its plantation suffer damage due to lack of winter chill and eventually implement corrective measures.

  14. A comparison of air particulate matter and associated polycyclic aromatic hydrocarbons in some tropical and temperate urban environments

    Science.gov (United States)

    Panther, B. C.; Hooper, M. A.; Tapper, N. J.

    A 12 month study of urban concentrations of total suspended particulates (TSP) and 20 polycyclic aromatic hydrocarbons (PAH) was carried out in Seoul (South Korea), Hong Kong, Bangkok (Thailand), Jakarta (Indonesia) and Melbourne (Australia). Concentrations of particulate matter in the atmosphere varied widely between the cities over the course of the study, ranging from a low of 24.1 ?g m -3 in Melbourne during the winter to a high of 376.2 ?g m -3 in Jakarta during the dry season. Seasonal variations in both TSP and PAH were observed in the tropical cities in the study with higher concentrations during the dry season and lower concentrations during the wet season. TSP and PAH concentrations are correlated with each other in these cities, suggesting that they have related sources and sinks for these cities. In the temperate cities of Melbourne and Seoul, PAH concentrations were higher during the cold winter season and lower during the warm summer. However, TSP was quite variable over the years in these latter cities and no clear seasonal trend was observed. A number of factors have been investigated which could be contributing to seasonal variations in pollutant levels. In the temperate climates, increased emissions due to the use of fossil fuels for heating in the winter is evident. However, an interrogation of the database with respect to the other factors such as (1) increased photolytic degradation during the summer, (2) transport of pollutants from other sources, (3) removal of PAH via wet deposition and in-cloud scavenging mechanisms and (4) volatilisation of lower molecular weight species during periods of high temperature indicates the importance of multiple processes. Even though there are clearly much lower levels of both particulates and PAH in the wet season of the tropical climates, no statistically significant correlations have been observed between rainfall levels and pollutant concentrations.

  15. Extremely low ozone content above the Russia in winter, 1995

    International Nuclear Information System (INIS)

    Results on monitoring the ozone layer state over Russia for the winter period of 1994/95 are presented. It is shown the area of the total ozone content reduction above 10% is located practically over the whole Russia. The area of the minimum ozone content values (deviations from the standard values above 20%) was located in January in the Pechora Region and in the North Urals. The minimum values zone in February was transferred to the territory of the Eastern Sibiria. The extremely low values of the total ozone content zone in Russia were observed in the course of the whole winter period. The unusual synoptic conditions significantly facilitated the ozone layer fast destruction. 2 refs

  16. On positivity in algebras of tempered generalized functions

    OpenAIRE

    Mayerhofer, Eberhard

    2008-01-01

    An explicit counterexample shows that contrary to the situation in the special Colombeau algebra, positivity and invertibility cannot be characterized pointwise in algebras of tempered generalized functions. Further a point value characterization of the latter is refined.

  17. Tempered-martensite embrittlement in a 12% Cr steel

    International Nuclear Information System (INIS)

    The nature of tempered martensite embrittlement in a 12% Cr steel was investigated using notched bar impact testing and Auger Electron Spectroscopy (AES). A minimum in the room temperature impact energy and a maximum in the ductile-brittle transition temperature occurred on tempering at 5000C (2 hours) and were associated with a low temperature cleavage fracture mode. The temperature of maximum embrittlement coincided with the tempering treatment producing the Cr7C3/M2X ? M23C6 carbide transformation. Tempering at temperatures > 5000C produced a progressive reduction in hardness, a decrease in the ductile-brittle transition and a change in the fracture mechanism in the lower shelf energy regime to a total or partial intergranular mode. AES measurements on the intergranular facets revealed segregation of phosphorus and a concomitant chromium enrichment, which could be tentatively explained in terms of a phosphorus segregation process controlled by the grain boundary precipitation of M23C6. (author)

  18. Hydrogen and temper embrittlement in 9Cr-1Mo steel

    International Nuclear Information System (INIS)

    The synergism between hydrogen embrittlement and temper embrittlement has been investigated in a 9Cr-1Mo martensitic steel. Measurements of tensile ductility were used to monitor the development of embrittlement with increasing hydrogen content in material as tempered and aged for up to 5000 h at 500 or 5500C. A detailed examination was made of associated changes in fracture mechanism, precipitate microstructure, and interfacial and precipitate chemistry. A strong interaction between hydrogen and temper embrittlement was observed. Both types of embrittlement in isolation reduced tensile ductility by promoting a ductile interlath fracture mechanism: 'chisel fracture'. Hydrogen and temper embrittlement acted synergistically to reduce ductility further by the promotion of brittle intergranular fracture and transgranular cleavage. The dominant factor controlling the interaction was the precipitation of a brittle intermetallic Laves phase containing phosphorus in solution. Phosphorus segregated to interfaces was considered to make an important, but secondary, contribution to the embrittlement observed. (author)

  19. Enhanced Sampling in the Well-Tempered Ensemble

    CERN Document Server

    Bonomi, M

    2009-01-01

    We introduce the well-tempered ensemble (WTE) which is the biased ensemble sampled by well-tempered metadynamics when the energy is used as collective variable. WTE can be designed so as to have approximately the same average energy as the canonical ensemble but much larger fluctuations. These two properties lead to an extremely fast exploration of phase space. An even greater efficiency is obtained when WTE is combined with parallel tempering. Unbiased Boltzmann averages are computed on the fly by a recently developed reweighting method [M. Bonomi et al. J. Comput. Chem. 30, 1615 (2009)]. We apply WTE and its parallel tempering variant to the 2d Ising model and to a Go-model of HIV protease, demonstrating in these two representative cases that convergence is accelerated by orders of magnitude.

  20. Kernel theorem for the space of Beurling - Komatsu tempered ultradistibutions

    OpenAIRE

    Lozanov-crvenkovic, Z.; Perisic, D.

    2007-01-01

    We give a simple proof of the Kernel theorem for the space of tempered ultradistributions of Beurling - Komatsu type, using the characterization of Fourier-Hermite coefficients of the elements of the space. We prove in details that the test space of tempered ultradistributions of Beurling - Komatsu type can be identified with the space of sequences of ultrapolynomal falloff and its dual space with the space of sequences of ultrapolynomial growth. As a consequence of the Kern...

  1. Computer simulation of quenched and tempered steel properties

    Directory of Open Access Journals (Sweden)

    B. Smoljan

    2011-06-01

    Full Text Available Purpose: The algorithm of estimation of mechanical properties based on steel hardness has been established.Design/methodology/approach: Numerical modelling of hardness distribution in as-quenched steel specimen was performed by involving the results of simple experimental test, i.e., Jominy-test. Hardness of quenched and tempered steel has been expressed as function of maximal hardness of actual steel and hardness of actual steel with 50% of martensite in microstructure, according to the time and temperature of tempering. After that distribution of other relevant mechanical properties was predicted based on predicted as-quenched and tempered hardness of steel. Experimental investigation has been performed on low alloy steel. The established procedure for estimation of quenched and tempered properties of steel has been applied in computer simulation of mechanical properties of quenched and tempered steel workpiece of complex form.Findings: Algorithm of estimation of hardness of quenched and tempered steel was improved. It can be concluded that working stress of quenched and tempered shaft can be successfully predicted by proposed method. The proposed computer simulation method could be applied in failure prevention.Research limitations/implications: The research was focused only on carbon and low alloyed heat treatable steels.Practical implications: The established algorithms can be used for prediction of mechanical properties in heat treating practice. Estimation of as-quenched hardness distribution is based on time, relevant for structure transformation, i.e., time of cooling from 800 to 500°C (t8/5. The hardness in the quenched and tempered state is estimated from the as-quenched hardness. The prediction of yield strength and toughness of steel is based on steel hardness.Originality/value: Hardness distribution is predicted by involving the results of simple experimental test, i.e., Jominy-test in numerical modelling of steel quenching.

  2. Induction of temperate cyanophage AS-1 by heavy metal – copper

    OpenAIRE

    Chu Tin-Chun; Hsu Shi-Fang; Platner Patricia J; Lui Doris; Lee Lee H; Gaynor John J; Vega Quinn C; Lustigman Bonnie K

    2006-01-01

    Abstract Background It has been reported that some marine cyanophage are temperate and can be induced from a lysogenic phase to a lytic phase by different agents such as heavy metals. However, to date no significant reports have focused on the temperate nature of freshwater cyanophage/cyanobacteria. Previous experiments with cyanophage AS-1 and cyanobacteria Anacystis nidulans have provided some evidence that AS-1 may have a lysogenic life cycle in addition to the characterized lytic cycle. R...

  3. Significance of Rate of Work Hardening in Tempered Martensite Embrittlement

    OpenAIRE

    Pietikainen, J.

    1995-01-01

    The main explanations for tempered martensite embrittlement are based on the effects of impurities and cementite precipitation on the prior austenite grain boundaries. There are some studies where the rate of work hardening is proposed as a potential reason for the brittleness. One steel was studied by means of a specially developed precision torsional testing device. The test steel had a high Si and Ni content so ? carbide and Fe3C appear in quite different tempering temperature ranges. The...

  4. Contribution to the modelling of chocolate tempering process.

    OpenAIRE

    Debaste, Fre?de?ric; Kegelaers, Yves; Ben Amor, Hatem; Halloin, Ve?ronique

    2007-01-01

    The tempering of chocolate, i.e. the process of crystallization of the desired morph; is a key step in its manufacturing by professional chocolatiers. In this work, a model of a tempering process based on seeding with solid chocolate grains is developed to enhance understanding and control of the system. The model aims to predict temperature field during melting and crystallization of the product. Therefore a mechanical stirrer is designed to simulate the manual mixing. Resulting flow field i...

  5. Spectrophotometry of the Jupiter at 0.6-1.1 ?m. Brightness distribution and optical parameters of the atmosphere in the tropical and temperate belts of the Jupiter

    International Nuclear Information System (INIS)

    Data on the brightness distribution in methane absorption bands 7250, 7900, 8610, 8860, 9870 A and in the continuum spectrum along the tropical and temperate belts of Jupiter are presented. The photoelectric scanning of the chosen regions on Jupiter's disk is carried out. The estimates of main optical parameters have been obtained for each investigated zone in terms of a two-layer atmospheric model (homogeneous infinite cloud layer and outer purely gaseous layer). On the basis of the obtained results the conclusion is made that the observed brightness distributions along the temperate belts of Jupiter and equatorial region are in good agreement with the model. The optical parameters of Jupiter cloud formation within the limits of the homogeneous model change considerably at transfers from one zone to another. The optical depth values of the supercloud atmosphere suffer relative changes within 30-50% limit, which points to the vibration of the cloud aerosol upper boundary

  6. Measurements for winter road maintenance

    OpenAIRE

    Riehm, Mats

    2012-01-01

    Winter road maintenance activities are crucial for maintaining the accessibility and traffic safety of the road network at northerly latitudes during winter. Common winter road maintenance activities include snow ploughing and the use of anti-icing agents (e.g. road salt, NaCl). Since the local weather is decisive in creating an increased risk of slippery conditions, understanding the link between local weather and conditions at the road surface is critically important. Sensors are commonly i...

  7. Influence of tempering temperature on mechanical properties of cast steels

    Directory of Open Access Journals (Sweden)

    G. Gola?ski

    2008-12-01

    Full Text Available The paper presents results of research on the influence of tempering temperature on structure and mechanical properties of bainite hardened cast steel: G21CrMoV4 – 6 (L21HMF and G17CrMoV5 – 10 (L17HMF. Investigated cast steels were taken out from internal frames of steam turbines serviced for long time at elevated temperatures. Tempering of the investigated cast steel was carried out within the temperature range of 690 ÷ 730 C (G21CrMoV4 – 6 and 700 ÷ 740 C (G17CrMoV5 – 10. After tempering the cast steels were characterized by a structure of tempered lower bainite with numerous precipitations of carbides. Performed research of mechanical properties has shown that high temperatures of tempering of bainitic structure do not cause decrease of mechanical properties beneath the required minimum.oo It has also been proved that high-temperature tempering (>720 oC ensures high impact energy at the 20% decrease of mechanical properties.

  8. Dung beetle communities: a neotropical-north temperate comparison

    Scientific Electronic Library Online (English)

    Meghan G, Radtke; Cláudio R V da, Fonseca; G Bruce, Williamson.

    2010-02-01

    Full Text Available Dung beetle communities have been compared across north temperate latitudes. Tropical dung beetle communities appear to be more diverse based on studies using different methodologies. Here, we present results from a standardized sampling protocol used to compare dung beetle communities across five n [...] eotropical forests in Brazil and Ecuador and two warm, north temperate forests in Mississippi and Louisiana. Species richness in the tropical forests was three to seven times higher than the temperate forests, as would be expected by studies of other taxa across tropical and temperate latitudes. Average body size in the temperate forests was larger than the tropical forests, as predicted by Bergmann's rule. Dung beetle abundance and volume per trap-day were generally higher in Ecuador than Brazil, and higher in Mississippi than Louisiana, but there were no tropical-temperate differences. Species rank-abundance curves were similar within countries and between countries. Rank-volume distributions indicated a smaller range of beetle body sizes in Ecuador versus Brazil or the USA. Community similarity was high within countries and low between countries. Community differences between Brazil and Ecuador sites may be explained by differences in productivity based on geological age of the soils.

  9. Annual movements of a steppe eagle (Aquila nipalensis) summering in Mongolia and wintering in Tibet

    Science.gov (United States)

    Ellis, D.H.; Moon, S.L.; Robinson, J.W.

    2001-01-01

    An adult female steppe eagle (Aquila nipalensis Hodgson) was captured and fitted with a satellite transmitter in June 1995 in southeastern Mongolia. In fall, it traveled southwest towards India as expected, but stopped in southeastern Tibet and wintered in a restricted zone within the breeding range of the steppe eagle. In spring, the bird returned to the same area of Mongolia where it was captured. These observations, though derived from the movements of a single bird, suggest three things that are contrary to what is generally believed about steppe eagle biology. First, not all steppe eagles move to warmer climes in winter. Second, not all steppe eagles are nomadic in winter. Finally, because our bird wintered at the periphery of the steppe eagle breeding range in Tibet, perhaps birds that breed in this same area also winter there. If so, not all steppe eagles are migratory.

  10. Coastal zone

    International Nuclear Information System (INIS)

    The report entitled Climate Change Impacts and Adaptation : A Canadian Perspective, presents a summary of research regarding the impacts of climate change on key sectors over the past five years as it relates to Canada. This chapter on the coastal zone focuses on the impact of climate change on Canada's marine and Great Lakes coasts with tips on how to deal with the impacts associated with climate change in sensitive environments. This report is aimed at the sectors that will be most affected by adaptation decisions in the coastal zone, including fisheries, tourism, transportation and water resources. The impact of climate change in the coastal zone may include changes in water levels, wave patterns, storm surges, and thickness of seasonal ice cover. The Intergovernmental Panel on Climate Change projects global average sea level will rise between 9 and 88 centimetres between 1990 to 2100, but not all areas of Canada will experience the same rate of future sea level change. The main physical impact would be shoreline change that could result in a range of biophysical and socio-economic impacts, some beneficial, some negative. The report focuses on issues related to infrastructure and communities in coastal regions. It is noted that appropriate human adaptation will play a vital role in reducing the extent of potential impacts by decreasing the vulnerability of average zone to climate change. The 3 main trends in coastal adaptation include: (1) increase in soft protectiion include: (1) increase in soft protection, retreat and accommodation, (2) reliance on technology such as geographic information systems to manage information, and (3) awareness of the need for coastal adaptation that is appropriate for local conditions. 61 refs., 7 figs

  11. The possibility of tribopair lifetime extending by welding of quenched and tempered stainless steel with quenched and tempered carbon steel

    OpenAIRE

    Marus?ic?, V.; Samardz?ic?, I.; Budic?, I.; Marus?ic?, L.

    2015-01-01

    In the conditions of tribocorrosion wear, extending of parts lifetime could be achieved by using stainless steel,which is hardened to sufficiently high hardness. In the tribosystem bolt/ bushing shell/link plate of the bucket elevator transporter conveyor machine, the previously quenched and tempered martensitic stainless steel for bolts is hardened at ?47 HRC and welded with the quenched and tempered high yield carbon steel for bolts. Additional material, based on Cr-Ni-Mo (18/8/6) is used...

  12. Inflatable Evergreen Polar Zone Dome (EPZD) Settlements

    OpenAIRE

    Bolonkin, Alexander; Cathcart, Richard

    2007-01-01

    Sustaining human life at the Earth antipodal Polar Regions is very difficult especially during Winter when water-freezing air temperature, blizzards and whiteouts make normal human existence dangerous. To counter these environmental stresses, we offer the innovative artificial Evergreen Polar Zone Dome (EPZD), an inflated half-hemisphere with interiors continuously providing a Mediterranean Sea-like climate. The Evergreen EPZD structural theory is developed, substantiated by...

  13. Historical Consumption of Heating Natural Gas and Thermal Monitoring of a Multifamily High-Rise Building in a Temperate/Cold Climate in Argentina

    OpenAIRE

    Celina Filippín; Silvana Flores Larsen

    2012-01-01

    This paper analyzes the historical consumption of natural gas in a multifamily high-rise building and the monitored winter thermal behavior of an apartment sample. The building is located in the center of Argentina (latitude: 36º27’S; longitude: 64º27’W), where the climate is a cold temperate with an absolute minimum temperature that may reach ?10 °C. The building has two blocks, North and South. The building’s annual gas consumption and its variability between 1996 and 2008 are shown. The So...

  14. Monitoring Change in Temperate Coniferous Forest Ecosystems

    Science.gov (United States)

    Williams, Darrel (Technical Monitor); Woodcock, Curtis E.

    2004-01-01

    The primary goal of this research was to improve monitoring of temperate forest change using remote sensing. In this context, change includes both clearing of forest due to effects such as fire, logging, or land conversion and forest growth and succession. The Landsat 7 ETM+ proved an extremely valuable research tool in this domain. The Landsat 7 program has generated an extremely valuable transformation in the land remote sensing community by making high quality images available for relatively low cost. In addition, the tremendous improvements in the acquisition strategy greatly improved the overall availability of remote sensing images. I believe that from an historical prespective, the Landsat 7 mission will be considered extremely important as the improved image availability will stimulate the use of multitemporal imagery at resolutions useful for local to regional mapping. Also, Landsat 7 has opened the way to global applications of remote sensing at spatial scales where important surface processes and change can be directly monitored. It has been a wonderful experience to have participated on the Landsat 7 Science Team. The research conducted under this project led to contributions in four general domains: I. Improved understanding of the information content of images as a function of spatial resolution; II. Monitoring Forest Change and Succession; III. Development and Integration of Advanced Analysis Methods; and IV. General support of the remote sensing of forests and environmental change. This report is organized according to these topics. This report does not attempt to provide the complete details of the research conducted with support from this grant. That level of detail is provided in the 16 peer reviewed journal articles, 7 book chapters and 5 conference proceedings papers published as part of this grant. This report attempts to explain how the various publications fit together to improve our understanding of how forests are changing and how to monitor forest change with remote sensing. There were no new inventions that resulted from this grant.

  15. Winter speed-up during a quiescent phase of surge-type glaciers: observations and implications

    Science.gov (United States)

    Abe, T.; Furuya, M.

    2014-12-01

    Glacier surface velocity is a combination of the internal deformation of ice and basal slip (including till deformation overlying bedrock) (Cuffey and Paterson, 2010). Short-term velocity changes can be attributed to basal slip associated with water pressure changes because of both the seasonal meltwater input and the evolution of the englacial and subglacial hydrological system. Thus, examining the velocity changes with high spatial and temporal resolution is helpful to understand how subglacial conditions evolve and control the surface velocities. We examined spatial and temporal velocity changes at quiescent surge-type glaciers near the border of Alaska/Yukon by SAR offset tracking and found significant acceleration from fall to winter regardless of surge events. Moreover, whereas the upstream propagating summer speed-up was observed, the winter speed-up propagated from upstream to downstream. Lingle and Fatland (2003) proposed the englacial water storages as the fundamental driver of temperate-glacier surge. Although our observations were performed at the quiescent and rather poly-thermal than temperate surge-type glaciers, our observations also support the englacial water storage hypothesis. Namely, the englacial water storages that do not directly connect to the surface can promote basal sliding through increased water pressure as winter approaches. Glacier surge often initiates in winter (Raymond, 1987), which has been explained by creep closure of efficient drainage system in fall and subsequent higher water pressure in winter. Mini-surges are also known in this area, and have been interpreted in a similar mechanism. However, in order to maintain the higher water pressure for some time period in winter, there should be such sources that can keep supplying the water to the bed. It has been uncertain, however, if, how and where the water can be stored in winter. Also, we should keep in mind that many of the previously known mini-surges were actually occurring in spring and summer (Kamb and Engelhardt, 1987; Harrison and Post, 2003). There are, to our knowledge, few comprehensive velocity observations in terms of both spatial and temporal coverages. Here we review some previous observations, place our observations in context of the glacier surge dynamics, and propose the winter speed-up mechanism.

  16. A note on the water budget of temperate glaciers

    Directory of Open Access Journals (Sweden)

    J. Oerlemans

    2013-06-01

    Full Text Available In this note the total dissipative melting in temperate glaciers is studied. The analysis is based on the notion that the dissipation is determined by the loss of potential energy, due to the downward motion of mass (ice, snow, meltwater and rain. A mathematical formulation of the dissipation is developed and applied to a simple glacier geometry. In a next step, meltwater production resulting from enhanced ice motion during a glacier surge is calculated. The amount of melt energy available follows directly from the lowering of the centre of gravity of the glacier. To illustrate the concept, schematic calculations are presented for a number of glaciers with different geometric characteristics. Typical dissipative melt rates, expressed as water-layer depth averaged over the glacier, range from a few cm per year for smaller glaciers to half a meter per year for Franz-Josef Glacier, one of the most active glaciers in the world (in terms of mass turnover. The total generation of meltwater during a surge is typically half a meter. For Variegated Glacier a value of 70 cm is found, for Kongsvegen 20 cm. These values refer to water layer depth averaged over the entire glacier. The melt rate depends on the duration of the surge. It is generally an order of magnitude larger than the water production by "normal" dissipation. On the other hand, the additional basal melt rate during a surge is comparable in magnitude to the water input from meltwater and precipitation. This suggests that enhanced melting during a surge does not grossly change the total water budget of a glacier. Basal water generated by enhanced sliding is an important ingredient of many theories of glacier surges. It provides a positive feedback mechanism that actually makes the surge happen. The results found here suggest that this can only work if water generated by enhanced sliding is accumulating in a part of the glacier base where surface meltwater and rain has no or very limited access. This finding seems compatible with the fact that on many glaciers surges are initiated in the lower accumulation zone.

  17. Effects of tempering on internal friction of carbon steels

    Energy Technology Data Exchange (ETDEWEB)

    Hoyos, J.J., E-mail: jjhoyos@unal.edu.co [Grupo de Ciencia y Tecnologia de los Materiales, Universidad Nacional de Colombia, Sede Medellin, Carrera 80 Numero 65-223, Medellin (Colombia); Ghilarducci, A.A., E-mail: friccion@cab.cnea.gov.ar [Centro Atomico Bariloche, Comision Nacional de Energia Atomica, Instituto Balseiro-Universidad Nacional de Cuyo, Consejo Nacional de Investigaciones Cientificas y Tecnologicas, Av. Bustillo 9500, 8400 Bariloche RN (Argentina); Salva, H.R., E-mail: salva@cab.cnea.gov.ar [Centro Atomico Bariloche, Comision Nacional de Energia Atomica, Instituto Balseiro-Universidad Nacional de Cuyo, Consejo Nacional de Investigaciones Cientificas y Tecnologicas, Av. Bustillo 9500, 8400 Bariloche RN (Argentina); Chaves, C.A., E-mail: cachaves@unal.edu.co [Grupo de Ciencia y Tecnologia de los Materiales, Universidad Nacional de Colombia, Sede Medellin, Carrera 80 Numero 65-223, Medellin (Colombia); Velez, J.M., E-mail: jmvelez@unal.edu.co [Grupo de Ciencia y Tecnologia de los Materiales, Universidad Nacional de Colombia, Sede Medellin, Carrera 80 Numero 65-223, Medellin (Colombia)

    2011-04-15

    Research highlights: {yields} Time tempering dependent microstructure of two steels is studied by internal friction. {yields} Internal friction indicates the interactions of dislocations with carbon and carbides. {yields} Internal friction detects the first stage of tempering. {yields} Precipitation hardening is detected by the decrease in the background. - Abstract: Two steels containing 0.626 and 0.71 wt.% carbon have been studied to determine the effects of tempering on the microstructure and the internal friction. The steels were annealed at 1093 K, quenched into water and tempered for 60 min at 423 K, 573 K and 723 K. The increase of the tempering time diminishes the martensite tetragonality due to the redistribution of carbon atoms from octahedrical interstitial sites to dislocations. Internal friction spectrum is decomposed into five peaks and an exponential background, which are attributed to the carbide precipitation and the dislocation relaxation process. Simultaneous presence of peaks P1 and P2 indicates the interaction of dislocations with the segregated carbon and carbide precipitate.

  18. Evolution of Microsatellite Loci of Tropical and Temperate Anguilla Eels

    Directory of Open Access Journals (Sweden)

    Mei-Chen Tseng

    2012-04-01

    Full Text Available Anguilla eels are divided into temperate and tropical eels, based on their major distributions. The present study collected two temperate eels, Anguilla japonica and Anguilla anguilla, and two tropical eels, Anguilla marmorata and Anguilla bicolor pacifica, to examine two questions: do temperate and tropical Anguilla eels have different genetic polymorphic patterns?; and do temperate Anguilla japonica and Anguilla anguilla have a closer relationship to each other than to tropical eels? In total, 274 sequences were cloned and sequenced from six conserved microsatellite loci to examine polymorphic patterns of these four catadromous eels. Different mutational events, including substitutions, and repeat-unit deletions and insertions, appeared in major regions, while different point mutations were observed in flanking regions. The results implied that parallel patterns of microsatellite sequences occurred within both tropical and temperate freshwater eels. Consensus flanking sequences of six homologous loci from each of the four species were constructed. Genetic distances ranged from 0.044 (Anguilla bicolor pacifica vs. Anguilla marmorata to 0.061 (Anguilla marmorata vs. Anguilla anguilla. The tree topology suggests the hypothesis of Anguilla japonica and Anguilla anguilla being a sister group must be rejected.

  19. Winter fuels report

    International Nuclear Information System (INIS)

    The Winter Fuels Report is intended to provide concise, timely information to the industry, the press, policymakers, consumers, analysts, and State and local governments on the following topics: distillate fuel oil net production, imports and stocks on a US level and for all Petroleum Administration for Defense Districts (PADD) and product supplied on a US level; propane net production, imports and stocks on a US level and for PADD's I, II, and III; natural gas supply and disposition and underground storage for the US and consumption for all PADD's, as well as selected National average prices; residential and wholesale pricing data for heating oil and propane for those States participating in the joint Energy Information Administration (EIA)/State Heating Oil and Propane Program; crude oil and petroleum price comparisons for the US and selected cities; and a 6-10 day, 30-Day, and 90-Day outlook for temperature and precipitation and US total heating degree-days by city

  20. A Winter's Tale

    Science.gov (United States)

    This resource explores winter weather and frozen precipitation. The page on precipitation points out that snow and rain are both water and explains how the different forms of frozen precipitation (snow, sleet, freezing rain) occur. There is a page on cirrus clouds that explains their characterstics and how they may affect climate by reflecting solar radiation or reducing outgoing infrared energy from Earth. The Jet Stream page explains the characteristics of these high-speed rivers of air, including what causes them and their effect on weather and climate. There is also a feature on the esthetic wonders of frozen water, including halos produced by ice crystals in the air, sparkling of snowflakes, why fresh snow squeaks when stepped on, and why it is silent during a snowfall. A bibliography is also provided.

  1. Is winter worse for stressed fish? The consequences of exogenous cortisol manipulation on over-winter survival and condition of juvenile largemouth bass.

    Science.gov (United States)

    Binder, Thomas R; O'Connor, Constance M; McConnachie, Sarah H; Wilson, Samantha M; Nannini, Michael A; Wahl, David H; Cooke, Steven J

    2015-09-01

    Over-winter mortality is an important selective force for warm-water fish (e.g., centrarchids) that live in temperate habitats. Inherent challenges faced by fish during winter may be compounded by additional stressors that activate the hypothalamic-pituitary-interrenal axis, either before or during winter, leading to negative sub-lethal impacts on fish health and condition, and possibly reducing chance of survival. We used experimental cortisol manipulation to test the hypothesis that juvenile largemouth bass (Micropterus salmoides) exposed to semi-chronic elevation in cortisol prior to winter would experience higher levels of over-winter mortality, physiological alterations and impaired immune status relative to control and sham-treated bass. Over-winter survival in experimental ponds was high, averaging 83%, and did not differ among treatment groups. Over the study period, bass exhibited an average increase in mass of 19.4%, as well as a slight increase in Fulton's condition factor, but neither measure differed among groups. Hepatosomatic index in cortisol-treated bass was 23% lower than in control fish, suggesting lower energy status, but white muscle lipid content was similar across all groups. Lastly, there was no difference in spleen somatic index or parasite load among treatment groups, indicating no long-term immune impairment related to our cortisol manipulation. The current study adds to a growing body of literature on glucocorticoid manipulations where field-based findings are not consistent with laboratory-based conceptual understanding of multiple stressors. This suggests that field conditions may provide fish with opportunities to mitigate negative effects of some stressors. PMID:26006297

  2. Stamen development and winter dormancy in apricot (Prunus armeniaca)

    Science.gov (United States)

    Julian, C.; Rodrigo, J.; Herrero, M.

    2011-01-01

    Background and Aims In temperate woody perennials, flower bud development is halted during the winter, when the buds enter dormancy. This dormant period is a prerequisite for adequate flowering, is genetically regulated, and plays a clear role in possibly adapting species and cultivars to climatic areas. However, information on the biological events underpinning dormancy is lacking. Stamen development, with clear differentiated stages, appears as a good framework to put dormancy in a developmental context. Here, stamen developmental changes are characterized in apricot (Prunus armeniaca) and are related to dormancy. Methods Stamen development was characterized cytochemically from the end of August to March, over 4 years. Developmental changes were related to dormancy, using the existing empirical information on chilling requirements. Key Results Stamen development continued during the autumn, and the flower buds entered dormancy with a fully developed sporogenous tissue. Although no anatomical changes were observed during dormancy, breaking of dormancy occurred following a clear sequence of events. Starch accumulated in particular places, pre-empting further development in those areas. Vascular bundles developed and pollen mother cells underwent meiosis followed by microspore development. Conclusions Dormancy appears to mark a boundary between the development of the sporogenous tissue and the occurrence of meiosis for further microspore development. Breaking of dormancy occurs following a clear sequence of events, providing a developmental context in which to study winter dormancy and to evaluate differences in chilling requirements among genotypes. PMID:21474504

  3. Ultra low carbon bainitic (ULCB) steels after quenching and tempering

    International Nuclear Information System (INIS)

    The mechanical and Charpy V impact strength properties of new advanced ultra low carbon bainitic (ULBC) steels after water quenching and tempering (WQT) have been investigated. Their chemical compositions are given. The nine continuous cooling transformation diagrams (CCT) of the new ULCB steel grades have been established. The CCT diagrams for ULCBNi steels containing 9% Ni - grade 10N9 and 5% Ni - grade HN5MVNb are given. The comparison between CCT diagrams of 3.5%Ni + 1.5%Cu containing steels grade HSLA 100 and HN3MCu is shown. The effect of the increase in carbon and titanium contents in the chemical composition of ULCBMn steels 04G3Ti, 06G3Ti and 09G3Ti on the kinetics of phase transformations during continuous cooling is presented by the shifting CCT diagrams. The Charpy V impact strength and brittle fracture occurence curves are shown. The effect of tempering temperature on tensile properties of WQT HN3MCu steel is shown and Charpy V impact strength curves after different tempering conditions are shown. The optimum tempering temperatures region of HN3MCu steel for high Charpy V impact toughness at law temperatures - 80oC(193 K) and -120oC(153 K) is estimated. The effect of tempering temperature on mechanical properties of HN5MVNb steel is given. The low temperature impact Charpy V toughness of HN5MVNb steel is shown. The optimum range of tempering temperature during 1 hour for high toughness of WQT HN5MVNb steel is gi high toughness of WQT HN5MVNb steel is given. HN3MCu and HN5MVNb steels after WQT have high yield strength YS?690 MPa and high Charpy V impact toughness KV?80 J at -100oC (173K) and KCV?50 J/cm2 at - 120oC (153K) so they may be used for cryogenic applications

  4. CO2 flux in a cool-temperate deciduous forest (Quercus mongolica of Mt. Nam in Seoul, Korea

    Directory of Open Access Journals (Sweden)

    Seung Jin Joo

    2011-03-01

    Full Text Available The Namsan Ecological Tower Site based on a flux tower was equipped with eddy covariance and automatic opening/closing chamber systems to collect long-term continuous measurements of CO2 flux, such as the net ecosystem exchange(NEE and soil CO2 efflux in a cool-temperate Quercus mongolica forest. The mean concentrations of atmosphericCO2 (705 mg/m3 during the summer were smaller than those measured (770 mg/m3 during the winter. The mean CO2flux during the summer period was negative (-0.34 mg m-2 s-1, while that during the winter period was positive (0.14 mgm-2 s-1. CO2 was deposited from the atmosphere to the surface in the summer. The daily mean value of soil CO2 effluxincreased from spring to summer. The seasonal pattern in the rate of soil CO2 efflux tightly followed the seasonal patternin soil temperatures. The Q10 values for soil CO2 efflux varied in a range from 2.12 to 3.26, and increased with increasingsoil depth. The maximum value of total carbon uptake (i.e., NEE during the growing season was -8 g CO2 m-2 day-1. At thesame time, the rate of soil CO2 efflux was 6.9 g CO2 m-2 day-1. The amplitude of flux variations in NEE was approximately14% larger than those in soil CO2 efflux. These results suggest that in cool-temperate regions of the Korean peninsula,the forest ecosystem of Q. mongolica may have a larger atmospheric CO2 uptake, due primarily to its high photosyntheticcapacity and low ecosystem respiration.

  5. Investigation of the parallel tempering method for protein folding

    International Nuclear Information System (INIS)

    We investigate the suitability and efficiency of an adapted version of the parallel tempering method for all-atom protein folding. We have recently developed an all-atom free energy force field (PFF01) for protein structure prediction with stochastic optimization methods. Here we report reproducible folding of the 20-amino-acid trp-cage protein and the conserved 40-amino-acid three-helix HIV accessory protein with an adapted parallel tempering method. We find that the native state, for both proteins, is correctly predicted to 2 A backbone root mean square deviation and analyse the efficiency of the simulation approach

  6. Influence of tempering temperature on mechanical properties of cast steels

    OpenAIRE

    Golan?ski, G.

    2008-01-01

    The paper presents results of research on the influence of tempering temperature on structure and mechanical properties of bainite hardened cast steel: G21CrMoV4 – 6 (L21HMF) and G17CrMoV5 – 10 (L17HMF). Investigated cast steels were taken out from internal frames of steam turbines serviced for long time at elevated temperatures. Tempering of the investigated cast steel was carried out within the temperature range of 690 ÷ 730 C (G21CrMoV4 – 6) and 700 ÷ 740 C (G17CrMoV5 – 10). Afte...

  7. Impacts of a changing winter precipitation regime on the Great Snowforest of British Columbia, Canada

    Science.gov (United States)

    Knudsvig, H.; Dery, S. J.; Coxson, D.

    2012-12-01

    Rising air temperatures have profoundly impacted British Columbia (BC) mountain ecosystems, including its Interior Wetbelt. This region supports the sole Interior Temperate Rainforest (ITR), or perhaps more appropriately "snowforest", of North America. This snowforest encompasses about 30,500 km2 and contains Western redcedar (Thuja plicata) and western hemlock (Tsuga heteropylla) in excess of 1500 years old. This region is projected to be one of the more vulnerable biogeoclimatic zones in BC due to forest operations and climate change. Loss of snow as a storage medium has the potential to negatively affect the forest. A decrease in snow water equivalent (SWE) has the potential to decrease soil moisture values; impacts of decreased water availability in this region have the possibility to affect soil moisture storage, vegetative species composition, flora and fauna interdependence, and pathogen outbreaks. Given the projected climate change in high latitude and altitude areas, this project analyzes the contemporary and potential future climate of BC's Interior Wetbelt and explores the possible environmental and ecohydrological impacts of climate change on the snowforest. Models project an increase in air temperature and precipitation but a decrease in snowfall in this region. Analyses of the snow depth, SWE, and temperature from the Upper Fraser River Basin automated snow pillow sites of the BC River Forecast Centre (RFC) were conducted; snow depth, SWE, and temperature were also measured at the field site via automated weather stations and bi-monthly snow surveys. Surveys recorded depth and SWE after observed peak accumulation and continued until snowpack was depleted in 80% of the field site. To determine the influence of precipitation on the soil moisture levels in the ITR, soil moisture and water table levels were measured for the 2011-12 water year in addition to meteorological conditions; snow, spring water, and near surface ground water samples were collected and analyzed for the environmental isotopes of deuterium and oxygen-18. Analysis of the RFC's snow pillow data shows April 1 snow depth has been highly variable in the last 25 years with an overall decline in depth and SWE values. Soil moisture values at the study site were consistent through the year but showed a peak during spring melt and a decline during August, the driest month of summer in this region. Isotopic analysis on the water samples is on-going. The Upper Fraser River Basin experienced an above-normal to record snowpack the winter of 2011-12, thus observed values may not be indicative of the overall trend for this area. Trends in this interconnected ecosystem can assist in determining impacts of climate change to northern climates.

  8. Soil organic carbon decomposition and carbon pools in temperate and sub-tropical forests in China.

    Science.gov (United States)

    Yang, L; Pan, J; Shao, Y; Chen, J M; Ju, W M; Shi, X; Yuan, S

    2007-11-01

    Decomposition of soil organic carbon (SOC) is a critical component of the global carbon cycle, and accurate estimates of SOC decomposition are important for forest carbon modeling and ultimately for decision making relative to carbon sequestration and mitigation of global climate change. We determined the major pools of SOC in four sites representing major forest types in China: temperate forests at Changbai Mountain (CBM) and Qilian Mountain (QLM), and sub-tropical forests at Yujiang (YJ) and Liping (LP) counties. A 90-day laboratory incubation was conducted to measure CO(2) evolution from forest soils from each site, and data from the incubation study were fitted to a three-pool first-order model that separated mineralizable soil organic carbon into active (C(a)), slow (C(s)) and resistant (C(r)) carbon pools. Results indicate that: (1) the rate of SOC decomposition in the sub-tropical zone was faster than that in the temperature zone, (2) The C(a) pool comprised approximately 1-3% of SOC with an average mean residence time (MRT) of 219 days. The C(s) pool comprised approximately 25-65% with an average MRT of 78 yr. The C(r) pool accounted for approximately 35-80% of SOC, (3) The YJ site in the sub-tropical zone had the greatest C(a) pool and the lowest MRT, while the QLM in the temperature zone had the greatest MRT for both the C(a) and C(s) pools. The results suggest a higher capacity for long-term C sequestration as SOC in temperature forests than in sub-tropical forests. PMID:17107746

  9. Cold thoughts on nuclear winter

    International Nuclear Information System (INIS)

    The nuclear winter controversy is a notorious example of the politicization of science. Large firestorms are followed by soot-laden black rain. It is not known what fraction of the soot produced by fires is removed from the atmosphere in this manner. A simple argument suggests that the fraction may be large. It is even possible to argue that a severe nuclear winter is not self-consistent. It is often assumed that carbonaceous soot is chemically inert in the atmosphere, despite the presence of trace amounts of chemically active species. Even if the magnitude of the nuclear winter effect were known, its implications would remain controversial. Nuclear winter chillings are usually measured as drops in mean temperature. However, reduction in solar heating reduces the diurnal variation as well

  10. The Challenge of Winter Backpacking.

    Science.gov (United States)

    Cavanaugh, Michael; Mapes, Alan

    1981-01-01

    Tips and techniques for safe and enjoyable winter backpacking are offered. Topics covered include cross county skis, snowshoes, clothing, footwear, shelter, sleeping bags, food, hypothermia prevention, as well as general rules and requirements. (CO)

  11. Deprivation and excess winter mortality

    OpenAIRE

    Shah, S.; Peacock, J.

    1999-01-01

    OBJECTIVE: To investigate the effect of material deprivation on the winter rise in mortality and temperature dependent variations in mortality. DESIGN: Ecological comparison of seasonal mortality at electoral ward level. Main outcome measures were ratios of winter to rest of the year mortality rates (seasonality ratios) and monthly deaths as the outcome variable in a model with monthly average temperature and Townsend score as main predictors. SETTING: Croydon, London, United Kingdom. S...

  12. Challenges in the nutrition and management of herbivores in the temperate zone

    OpenAIRE

    Vuuren, A. M.; Chilibroste, P.

    2013-01-01

    The expected higher global demand for animal proteins and the competition for starch and sugars between food, fuel and feed seem to favour herbivores that convert solar energy captured in fibrous plants into animal products. However, the required higher production level of herbivores questions the sustainability of this conversion. An increase in herbivore production can be achieved by increasing the number of animals associated with the increasing demand of plant biomass or by improving the ...

  13. Studies on the Cold Hardiness of Some Temperate Zone Fruit Species and Cultivars

    OpenAIRE

    KÜDEN, Ayzin B.; KÜDEN, Ali; PAYDA?, Sevgi; Nurettin KA?KA; ?MRAK, Burhanettin

    1998-01-01

    The research was carried out on apple, peach, nectarine and apricot cultivars during 1992-1994. In this work, the cold hardiness of apple, peach, nectarine and apricot cultivars were investigated. For this purpose, the relationship between the carbonhydrates or plant nutrient elements and the cold hardiness of the cultivars were investigated by viability tests. According to the results, apples and among them Granny Smith and Starkrimson cultivars, J.H. Hale and Monroe peach cultivars amon...

  14. Climate signatures in corals of the tropical-temperate transition zone (Late Miocene, Crete/Greece)

    OpenAIRE

    Reuter, Markus

    2006-01-01

    In dieser Arbeit wird erstmalig ein ober-miozänes Karbonatsystem von der Insel Kreta (Griechenland) beschrieben, das sowohl Merkmale tropischer als auch temperater Karbonatsysteme enthält. Stratale Geometrien und Faziesmuster belegen für das Arbeitsgebiet (Westrand des Heraklion Beckens) ein aktives Halbgrabensystem mit ausgeprägtem submarinen Relief, das durch synsedimentäre Bewegungen zahlreicher Kippschollen kontrolliert wurde. Die übereinstimmenden coastal onlap Muster in den unters...

  15. "Winter is coming"

    CERN Document Server

    Kostov, Veselin; Hartman, Nikolaus; Guzewich, Scott; Rogers, Justin

    2013-01-01

    Those that do not sow care little about such mundane things as equinoxes or planting seasons, or even crop rotation for that matter. Wherever and whenever the reavers reave, the mood is always foul and the nights are never warm or pleasant. For the rest of the good folks of Westeros, however, a decent grasp of the long-term weather forecast is a necessity. Many a maester have tried to play the Game of Weather Patterns and foretell when to plant those last turnip seeds, hoping for a few more years of balmy respite. Tried and failed. For other than the somewhat vague (if not outright meaningless) omens of "Winter is Coming", their meteorological efforts have been worse than useless. To right that appalling wrong, here we attempt to explain the apparently erratic seasonal changes in the world of G.R.R.M. A natural explanation for such phenomena is the unique behavior of a circumbinary planet. Thus, by speculating that the planet under scrutiny is orbiting a pair of stars, we utilize the power of numerical three-...

  16. Winter fuels report

    Energy Technology Data Exchange (ETDEWEB)

    1994-10-01

    The Winter Fuels Report is intended to provide concise, timely information to the industry, the press, policymakers, consumers, analysts, and State and local governments on the following topics: Distillate fuel oil net production, imports and stocks on a US level and for all Petroleum Administration for Defense Districts (PADD) and product supplied on a US level; propane net production, imports and stocks on a US level and for PADD`s I, II, and III; natural gas supply and disposition and underground storage for the US and consumption for all PADD`s; as well as selected National average prices; residential and wholesale pricing data for heating oil and propane for those States participating in the joint Energy Information Administration (EIA)/State Heating Oil and Propane Program; crude oil and petroleum price comparisons for the US and selected cities; and a 6-10 Day, 30-Day, and 90-Day outlook for temperature and precipitation and US total heating degree-days by city.

  17. Klaus Winter (1930 - 2015)

    CERN Multimedia

    2015-01-01

    We learned with great sadness that Klaus Winter passed away on 9 February 2015, after a long illness.   Klaus was born in 1930 in Hamburg, where he obtained his diploma in physics in 1955. From 1955 to 1958 he held a scholarship at the Collège de France, where he received his doctorate in nuclear physics under the guidance of Francis Perrin. Klaus joined CERN in 1958, where he first participated in experiments on ?+ and K0 decay properties at the PS, and later became the spokesperson of the CHOV Collaboration at the ISR. Starting in 1976, his work focused on experiments with the SPS neutrino beam. In 1984 he joined Ugo Amaldi to head the CHARM experiment, designed for detailed studies of the neutral current interactions of high-energy neutrinos, which had been discovered in 1973 using the Gargamelle bubble chamber at the PS. The unique feature of the detector was its target calorimeter, which used large Carrara marble plates as an absorber material. From 1984 to 1991, Klau...

  18. Temperature acclimation of mitochondria function from the hearts of a temperate wrasse (Notolabrus celidotus).

    Science.gov (United States)

    Iftikar, F I; Morash, A J; Cook, D G; Herbert, N A; Hickey, A J R

    2015-06-01

    Understanding how mitochondrial function alters with acclimation may provide insight to the limits these organelles place on temperate fish hearts facing seasonal temperature fluctuations. This investigation determined if compromised cardiac mitochondrial function contributed to heart failure (HF) in the New Zealand wrasse Notolabrus celidotus acclimated at their mean summer and winter ocean temperatures. To test this hypothesis, fish were acclimated to cold (CA, 15°C) and warm (WA, 21°C) temperatures. The temperature of HF was determined by Doppler sonography and mitochondrial function in permeabilised cardiac fibres was tested using high resolution respirometry. Heat stress mediated HF occurred at a THF of 26.7±0.4°C for CA fish, and at 28.2±0.6°C for WA fish. Biochemical analyses also revealed that WA fish had elevated resting plasma lactate indicating an increased dependence on anaerobic pathways. When cardiac fibres were tested with increasing temperatures, apparent breakpoints in the respiratory control ratio (RCR-I) with substrates supporting complex I (CI) oxygen flux occurred below the THF for both acclimated groups. While WA cardiac mitochondria were less sensitive to increasing temperature for respirational flux supported by CI, Complex II, and chemically uncoupled flux, CA fish maintained higher RCRs at higher temperatures. We conclude that while acclimation to summer temperatures does alter cardiac mitochondrial function in N. celidotus, these changes need not be beneficial in terms of oxidative phosphorylation efficiency and may come at an energetic cost, which would be detrimental in the face of further habitat warming. PMID:25645295

  19. Shifts of climate zones in multi-model climate change experiments using the Koeppen climate classification

    Energy Technology Data Exchange (ETDEWEB)

    Hanf, Franziska; Koerper, Janina; Spangehl, Thomas; Cubash, Ulrich [Freie Univ. Berlin (Germany). Inst. fuer Meteorologie

    2012-04-15

    This study investigates the future changes in the climate zones' distribution of the Earth's land area due to increasing atmospheric greenhouse gas concentrations in three IPCC SRES emissions scenarios (A1B, A2 and B1). The Koeppen climate classification is applied to climate simulations of seven atmosphere-ocean general circulation models (AOGCMs) and their multi-model mean. The evaluation of the skill of the individual climate models compared to an observation-reanalysis-based climate classification provides a first order estimate of relevant model uncertainties and serves as assessment for the confidence in the scenario projections. Uncertainties related to differences in simulation pathways of the future projections are estimated by both, the multi-model ensemble spread of the climate change signals for a given scenario and differences between different scenarios. For the recent climate the individual models fail to capture the exact Koeppen climate types in about 24-39 % of the global land area excluding Antarctica due to temperature and precipitation biases, while the multi-model ensemble mean simulates the present day observation-reanalysis-based distribution of the climate types more accurately. For the end of the 21{sup st} century compared to the present day climate the patterns of change are similar across the three scenarios, while the magnitude of change is largest for the highest emission scenario. Moreover, the temporal development of the climate shifts from the end of the 20st century and during the 21{sup st} century show that changes of the multi-model ensemble mean for the A2 and B1 scenario are generally within the ensemble spread of the individual models for the A1B scenario, illustrating that for the given range of scenarios the model uncertainty is even larger than the spread given by the different GHG concentration pathways. The multi-model ensemble mean's projections show climate shifts to dryer climates in the subtropics (Australia, Mediterranean Basin, southern Africa). This is consistent with an increase of area classified as Tropical Savanna Climate as well as Dry Climates. Furthermore, there is a poleward extension of the warmer climate types in the northern hemisphere causing a retreat of regions with Cold Climate with Moist Winter and Tundra Climate. The European region shows largest changes comparing the shifts in the different continents (37.1 % of the European land area) as a result of a large extension of the Humid Temperate Climate across eastern and north-eastern Europe at the cost of the Cold Climate with Moist Winter. (orig.)

  20. Tempered Water Lower Port Connector Structural Analysis Verification

    International Nuclear Information System (INIS)

    Structural analysis of the lower port connection of the Tempered Water System of the Cold Vacuum Drying Facility was performed. Subsequent detailed design changes to enhance operability resulted in the need to re-evaluate the bases of the original analysis to verify its continued validity. This evaluation is contained in Appendix A of this report. The original evaluation is contained in Appendix B

  1. Protein Folding with the Adaptive Tempering Monte Carlo Method

    Science.gov (United States)

    Dong, X.; Klimov, D.; Blaisten-Barojas, E.

    Characterization of the folding transition in a model protein was achieved with the recent multicanonical tempering method implemented with Monte Carlo the adaptive tempering Monte Carlo (ATMC) (X. Dong and E. Blaisten-Barojas. Adaptive tempering Monte Carlo method. J. Comput. Theor. Nanosci., 3, p. 118 2006). The folding transition temperature was successfully determined and a spread of states was observed around the interface between native and folded regions. Energy states collected from all tempering events in a series of parallel runs were used in the calculation of the free energy, internal energy, order parameter and radius of gyration as a function of temperature through the weighted histogram method. Not only the calculated thermodynamic properties are in good agreement with results from Langevin dynamics simulations (D. K. Klimov and D. Thirumalai. Native topology determines forced-induced pathways in global proteins. Proc. Natl. Acad. Sci. USA. 97, p. 7254 2000), but also this multicanonical approach is noticeably more efficient because of the adaptive manner in which the system visits states near a transition in the interface between two phases. Additionally, the ATMC is advantageous for protein simulation over regular single canonical ensemble methods because it accelerates the hopping between local energy minima on the potential energy surface.

  2. Density Estimates for SDES Driven by Tempered Stable Processes

    OpenAIRE

    Huang, L.

    2015-01-01

    We study a class of stochastic differential equations driven by a possibly tempered L{\\'e}vy process, under mild conditions on the coefficients. We prove the well-posedness of the associated martingale problem as well as the existence of the density of the solution. Two sided heat kernel estimates are given as well. Our approach is based on the Parametrix series expansion

  3. Why Do Some Evergreen Species Keep Their Leaves for a Second Winter, While Others Lose Them?

    Directory of Open Access Journals (Sweden)

    Peter J. Grubb

    2014-10-01

    Full Text Available In subtropical montane semi-moist forest in SW China (SMSF, a large majority of evergreen tree and tall shrub species was found to have only one cohort of old leaves in early spring. In contrast, almost all species of evergreen tree and tall shrub in warm temperate rain forest (WTRF in Japan and sclerophylls in Mediterranean-climate forest (MSF of the Mediterranean Basin have two or more cohorts of old leaves in early spring; they drop their oldest cohort during or soon after leaf outgrowth in spring. Japanese WTRF has no dry season and MSF a dry summer. SMSF has a dry winter. On four evergreen Rhododendron species from SW China with only one cohort of old leaves in spring when in cultivation in Scotland, the majority of leaves in the senescing cohort fell by the end of December. We hypothesize that with dry winters, there is an advantage to dropping older leaves in autumn, because there is a low chance of appreciable positive assimilation in winter and a high chance of desiccation, reducing the resorption of dry mass and mineral nutrients from ageing leaves. Our hypothesis may be extended to cover evergreens at high altitude or high latitude that experience cold soils in winter.

  4. The middle intertidal zone

    Science.gov (United States)

    Katie Hale (CSUF; Biological Sciences)

    2007-06-08

    The middle intertidal zone is submerged during high tide and only exposed during low tides. This zone has the most moderate conditions of the zones and has many algae, sea anemones, mollusks, and crustaceans.

  5. The upper intertidal zone

    Science.gov (United States)

    Katie Hale (CSUF; Biological Sciences)

    2007-06-08

    The upper intertidal zone is exposed most of the time and will become submerged only during high tide. This zone is least abundant of the intertidal zones but contains some mollusks, barnacles, and other animals adapted to avoid drying out.

  6. The bottom intertidal zone

    Science.gov (United States)

    Katie Hale (CSUF; Biological Sciences)

    2007-06-08

    The bottom intertidal area remains under water except during low tides. This zone is most abundant of the intertidal zones and contains seaweeds and other plants, invertebrates, and fishes. The bottom zone is subject to the most intense wave action.

  7. The middle intertidal zone

    Science.gov (United States)

    Katie Hale (California State University, Fullerton; Student, Biological Sciences)

    2007-01-04

    The middle intertidal zone is submerged during high tide and only exposed during low tides. This zone has the most moderate conditions of the zones and has many algae, sea anemones, mollusks, and crustaceans.

  8. The upper intertidal zone

    Science.gov (United States)

    Katie Hale (California State University, Fullerton; Student, Biological Sciences)

    2007-01-04

    The upper intertidal zone is exposed most of the time and will become submerged only during high tide. This zone is least abundant of the intertidal zones but contains some mollusks, barnacles, and other animals adapted to avoid drying out.

  9. The bottom intertidal zone

    Science.gov (United States)

    Katie Hale (California State University, Fullerton; Student, Biological Sciences)

    2007-01-04

    The bottom intertidal area remains under water except during low tides. This zone is most abundant of the intertidal zones and contains seaweeds and other plants, invertebrates, and fishes. The bottom zone is subject to the most intense wave action.

  10. Groundwater flow modelling of periods with temperate climate conditions - Forsmark

    International Nuclear Information System (INIS)

    As a part of the license application for a final repository for spent nuclear fuel at Forsmark, the Swedish Nuclear Fuel and Waste Management Company (SKB) has undertaken a series of groundwater flow modelling studies. These represent time periods with different climate conditions and the simulations carried out contribute to the overall evaluation of the repository design and long-term radiological safety. This report concerns the modelling of a repository at the Forsmark site during temperate conditions; i.e. from post-closure and throughout the temperate period up until the receding shoreline leaves the modelling domain at around 12,000 AD. The collation and implementation of onsite hydrogeological and hydrogeochemical data from previous reports are used in the construction of a hydrogeological base case (reference case conceptualisation) and then in an examination of various areas of uncertainty within the current understanding by a series of model variants. The hydrogeological base case models at three different scales, 'repository', 'site' and 'regional', make use of continuous porous medium (CPM), equivalent continuous porous medium (ECPM) and discrete fracture network (DFN) models. The use of hydrogeological models allow for the investigation of the groundwater flow from a deep disposal facility to the biosphere and for the calculation of performance measures that will provide an input to the site performance assessment. The focus of the study described in this report has been to perform numerical simulations of the hydrogeological system from post-closure and throughout the temperate period. Besides providing quantitative results for the immediate temperate period following post-closure, these results are also intended to give a qualitative indication of the evolution of the groundwater system during future temperate periods within an ongoing cycle of glacial/inter-glacial events

  11. Groundwater flow modelling of periods with temperate climate conditions - Forsmark

    Energy Technology Data Exchange (ETDEWEB)

    Joyce, Steven; Simpson, Trevor; Hartley, Lee; Applegate, David; Hoek, Jaap; Jackson, Peter; Swan, David (Serco Technical Consulting Services (United Kingdom)); Marsic, Niko (Kemakta Konsult AB (Sweden)); Follin, Sven (SF GeoLogic AB (Sweden))

    2010-11-15

    As a part of the license application for a final repository for spent nuclear fuel at Forsmark, the Swedish Nuclear Fuel and Waste Management Company (SKB) has undertaken a series of groundwater flow modelling studies. These represent time periods with different climate conditions and the simulations carried out contribute to the overall evaluation of the repository design and long-term radiological safety. This report concerns the modelling of a repository at the Forsmark site during temperate conditions; i.e. from post-closure and throughout the temperate period up until the receding shoreline leaves the modelling domain at around 12,000 AD. The collation and implementation of onsite hydrogeological and hydrogeochemical data from previous reports are used in the construction of a hydrogeological base case (reference case conceptualisation) and then in an examination of various areas of uncertainty within the current understanding by a series of model variants. The hydrogeological base case models at three different scales, 'repository', 'site' and 'regional', make use of continuous porous medium (CPM), equivalent continuous porous medium (ECPM) and discrete fracture network (DFN) models. The use of hydrogeological models allow for the investigation of the groundwater flow from a deep disposal facility to the biosphere and for the calculation of performance measures that will provide an input to the site performance assessment. The focus of the study described in this report has been to perform numerical simulations of the hydrogeological system from post-closure and throughout the temperate period. Besides providing quantitative results for the immediate temperate period following post-closure, these results are also intended to give a qualitative indication of the evolution of the groundwater system during future temperate periods within an ongoing cycle of glacial/inter-glacial events

  12. An empirical exploration of the world oil price under the target zone model

    International Nuclear Information System (INIS)

    This paper investigates the behavior of the world oil price based on the first-generation target zone model. Using anecdotal data during the period of 1988-1999, we found that OPEC has tried to maintain a weak target zone regime for the oil price. Our econometric tests suggest that the movement of the oil price is not only manipulated by actual and substantial interventions by OPEC but also tempered by market participants' expectations of interventions. As a consequence, the non-linear model based on the target zone theory has very good forecasting ability when the oil price approaches the upper or lower limit of the band

  13. An empirical exploration of the world oil price under the target zone model

    International Nuclear Information System (INIS)

    This paper investigates the behavior of the world oil price based on the first-generation target zone model. Using anecdotal data during the period of 1988-1999, we found that OPEC has tried to maintain a weak target zone regime for the oil price. Our econometric tests suggest that the movement of the oil price is not only manipulated by actual and substantial interventions by OPEC but also tempered by market participants' expectations of interventions. As a consequence, the non-linear model based on the target zone theory has very good forecasting ability when the oil price approaches the upper or lower limit of the band. (author)

  14. Investigation into the Influence of Post-Weld Heat Treatment on the Friction Stir Welded AA6061 Al-Alloy Plates with Different Temper Conditions

    Science.gov (United States)

    ?peko?lu, Güven; Erim, Seçil; Çam, Gürel

    2014-02-01

    In this study, the effect of post-weld heat treatment (PWHT) on the microstructure and mechanical properties of friction stir butt-joined AA6061 Al-alloy plates both in O and T6-temper conditions was investigated by detailed microstructural investigations and microhardness measurements, in combination with transverse tensile testing. It was determined that the PWHT might result in abnormal grain growth (AGG) in the weld zone particularly in the joints produced in O-temper condition depending on the weld parameters used during friction stir welding. The PWHT generally led to an improvement in the mechanical properties even if AGG took place. Thus, the post-weld heat-treated joints exhibited mechanical properties much higher than those of respective as-welded plates and comparable to those of the respective base plates.

  15. Tree species composition influences dependence of climate forcing on spring phenology across temperate deciduous broadleaf forests in Eastern United States

    Science.gov (United States)

    Melaas, E. K.; Friedl, M. A.; Richardson, A. D.

    2014-12-01

    Phenological events in temperate deciduous forests, such as bud burst and senescence, exert strong control over seasonal fluxes of water, energy and carbon. The timing of these transitions is influenced primarily by air temperature, which makes them robust indicators of biological responses to climate change. However, the exact nature and magnitude of these controls is currently poorly understood. In this paper, we used a combination of surface meteorological data, species composition maps, remote sensing, and ground-based observations, including camera-based time series of canopy greenness from PhenoCams and citizen science data from the USA-National Phenology Network, to develop and test models that predict the timing of spring leaf emergence across several different deciduous broadleaf forest types in the eastern contiguous United States (68°W-95°W, 30°N-50°N). As part of this analysis, we analyzed two existing land surface model phenology subroutines and specifically examined predictions for two years with anomalously warm temperatures during dormancy to investigate the role of chilling. The results indicate significant differences in cumulative heating requirements and photoperiod cues among forest types. Moreover, we found that regional patterns of species composition explain spatial variation in prediction errors from existing models. In addition, we identified a marginal, but statistically significant decrease in model bias when chilling requirements were included during an anomalously warm winter with average spring temperatures, but no significant improvement when both winter and springtime temperatures were more representative of future climate.

  16. Oxygenated polycyclic aromatic hydrocarbons and azaarenes in urban soils: a comparison of a tropical city (Bangkok) with two temperate cities (Bratislava and Gothenburg).

    Science.gov (United States)

    Bandowe, Benjamin A Musa; Lueso, María Gómez; Wilcke, Wolfgang

    2014-07-01

    Environmental conditions in the tropics favor the formation of polar polycyclic aromatic compound (polar PACs, such as oxygenated PAHs [OPAHs] and azaarenes [AZAs]), but little is known about these hazardous compounds in tropical soils. The objectives of this work were to determine (i) the level of contamination of soils (0-5 and 5-10 cm layers) from the tropical metropolis of Bangkok (Thailand) with OPAHs and AZAs and (ii) the influence of urban emission sources and soil properties on the distribution of PACs. We hypothesized that the higher solar insolation and microbial activity in the tropics than in the temperate zone will lead to enhanced secondary formation of OPAHs. Hence, OPAH to related parent-PAH ratios will be higher in the tropical soils of Bangkok than in temperate soils of Bratislava and Gothenburg. The concentrations of ?15OPAHs (range: 12-269 ng g(-1)) and ?4AZAs (0.1-31 ng g(-1)) measured in soils of Bangkok were lower than those in several cities of the industrialized temperate zone. The ?15OPAHs (r=0.86, pBangkok were mostly higher than those of Bratislava and Gothenburg (e.g. 9-fluorenone/fluorene concentration ratio was 12.2 ± 6.7, 5.6 ± 2.4, and 0.7 ± 02 in Bangkok, Bratislava and Gothenburg soils, respectively) supporting the view that tropical environmental conditions and higher microbial activity likely lead to higher OPAH to parent-PAH ratios in tropical than in temperate soils. PMID:24529396

  17. A late Middle Pleistocene temperate periglacial temperate sequence (Oxygen Isotope Stages 7 5e) near Marsworth, Buckinghamshire, UK

    Science.gov (United States)

    Murton, J. B.; Baker, A.; Bowen, D. Q.; Caseldine, C. J.; Coope, G. R.; Currant, A. P.; Evans, J. G.; Field, M. H.; Green, C. P.; Hatton, J.; Ito, M.; Jones, R. L.; Keen, D. H.; Kerney, M. P.; McEwan, R.; McGregor, D. F. M.; Parish, D.; Robinson, J. E.; Schreve, D. C.; Smart, P. L.

    2001-12-01

    River-channel and colluvial deposits, near Marsworth, Buckinghamshire, record a temperate-periglacial-temperate sequence during the late Middle Pleistocene. The deposits of a lower channel contain tufa clasts bearing leaf impressions that include Acer sp., and Sorbus aucuparia and containing temperate arboreal pollen attributed to ash-dominated woodland. The tufa probably formed at the mouth of a limestone spring before being redeposited in a small river whose deposits contain plant remains, Mollusca, Coleoptera, Ostracoda and vertebrate bones of temperate affinities. The sediments, sedimentary structures and limited biological remains above the Lower Channel deposits indicate that fluvial deposition preceded climatic cooling into periglacial conditions. Fluvial deposition recurred during a later temperate episode, as shown by the mammalian bone assemblage in stratigraphically higher channel deposits. The Upper Channel deposits are confidently attributed to Oxygen Isotope Sub-Stage 5e (Ipswichian) on the basis of their vertebrate remains. However, the age of the Lower Channel deposits is less clear. The mammalian and coleopteran remains in the Lower Channel strongly suggest correlation with Oxygen Isotope Stage 7 on the basis of their similarities to other sites whose stratigraphy is better known and the clear difference of the Lower Channel assemblage from well-established faunas of Ipswichian or any other age. By contrast, U-Th dating of the tufa clasts suggests an age post 160 ka BP, while Aile/Ile ratios on Mollusca point to an Ipswichian age and younger. Four ways of interpreting this age discrepancy are considered, the preferred one correlating the Lower Channel deposits with Oxygen Isotope Stage 7.

  18. Neopaleozoic flora in stratigraphic zones of Gondwana

    Energy Technology Data Exchange (ETDEWEB)

    Archangelsky, S.

    1984-01-01

    Carboniferous and Permian floristic sequences in Gondwana and adjacent areas are analyzed. These data are distributed on palaeogeographic maps that correspond to four chronologic segments: lower Carboniferous-early middle Carboniferous, early middle Carboniferous-middle late Carboniferous, lower Permian and upper Permian. A correlation of zones and floral assemblages during the late Palaeozoic is proposed on the base of recent data. The distribution of possible periglacial sediments (diamictites) is also included in the sequences. It is concluded that palaeogeography conditioned the floristic development in Gondwana. An independent evolution of different gondwanic areas is suggested by the continuous change in their palaeolatitudinal disposition. South Africa and South America had a similar development during the Permian and belong to the Northafroamerican Palaeofloristic Province. During the same period, on the other hand, Australia, India and Antartica had a more temperate climatic regime, being located nearer the pole; they may belong to the Indoaustralian Palaefloristic Province. 44 refs.

  19. Properties of heat affected zones in repair welds of pressure vessel steels

    International Nuclear Information System (INIS)

    This study has revealed that the trempering of the HAZ of a repair weld will remain inadequate both with the half-bead and temper-bead technique. In the case of the half-bead-technique, the temperature penetration is too extensive causing reaustenitization of the HAZ and almost no tempering. The temper-bead method seems on the average to be better but due to the fluctuation and the narrow benefical temperature range the HAZ will not be completely tempered. The results of weld thermal simulations have shown that the ductility of the HAZ can be properly restored only when due to the second weld layer the peak temperature in the HAZ falls between 5700C and 7200C. The depth of this temperature zone is less than 2 mm and thus too small for the perfect realization of the ideas of the half-bead or temper-bead methods. However, the impact ductility of the HAZ is fairly good for both methods because the the HAZ contains frequent tough obstacles which prevent the cracks to run along the HAZ. (orig.)

  20. Environmental Controls and Management Effects on Ecosystem Carbon Exchange in Two Grazed Temperate Grasslands

    Science.gov (United States)

    Ni Choncubhair, O.; Humphreys, J.; Lanigan, G.

    2013-12-01

    Temperate grasslands constitute over 30% of the Earth's naturally-occurring biomes and make an important contribution towards the partial mitigation of anthropogenic greenhouse gas emissions by terrestrial ecosystems. Accumulation of carbon (C) in grassland systems predominantly takes place in below-ground repositories, enhanced by the presence of a stable soil environment with low carbon turnover rates, active rhizodeposition and high levels of residue and organic inputs. However, this C sequestration is strongly influenced by soil characteristics and climatic variables. Furthermore, in managed pasture systems, carbon exchange across the soil-atmosphere boundary is additionally affected by management activities, such as biomass removal, grazing events and the deposition or application of organic amendments. These biotic and abiotic factors contribute greatly towards the large uncertainty associated with the carbon balance of grassland ecosystems and demand further analysis. In the present study, the controls and drivers of carbon dynamics in two rotationally-grazed grasslands in Ireland were examined. The sites experience similar temperate climatic regimes but differ in soil texture classification and stocking rate. Eddy covariance measurements of net ecosystem exchange of carbon were complemented by regular assessment of standing biomass, leaf cover, harvest exports and organic amendment inputs. Our study showed that mild weather conditions and an extended growing season sustained net C accumulation at both sites for at least ten months of the year. Despite differing soil drainage characteristics, winter fluxes of net carbon exchange and its component fluxes, gross photosynthesis and ecosystem respiration, were highly comparable between the two sites. Management practices during the active growing season exerted a strong influence on both the direction and the rate of C exchange in the grassland systems, with a strong dependence, however, on the timing and intensity of the management effect. Harvest-induced reductions in productivity and net C uptake were generally greater than grazing-induced shifts, however the effects were at times mediated by environmental conditions. Our research highlighted the complex nature of the investigated grasslands resulting from the heterogeneous footprint induced by rotational grazing, grass harvesting and intensive management practices. Further work will focus on the applicability of different gap-filling methodologies for capturing the temporal and spatial variability observed. The potential of vegetation indices as a means of tracking sward development will also be investigated, with the aim of improving our understanding of the impact of vegetation dynamics on measured ecosystem carbon fluxes.

  1. Mice May Yield Clues to Winter Depression

    Science.gov (United States)

    ... 152453.html Mice May Yield Clues to Winter Depression Brain research suggests time of year you're ... 6 percent of Americans -- is a type of depression that occurs during winter. It's thought to be ...

  2. Classification guide: Sochi 2014 Paralympic Winter Games

    OpenAIRE

    2014-01-01

    The Sochi 2014 Paralympic Winter Games classification guide is designed to provide National Paralympic Committees (NPCs) and International Federations (IFs) with information about the classification policies and procedures that will apply to the Sochi 2014 Paralympic Winter Games.

  3. The tempered stable process with infinitely divisible inverse subordinators

    International Nuclear Information System (INIS)

    In the last decade processes driven by inverse subordinators have become extremely popular. They have been used in many different applications, especially for data with observable constant time periods. However, the classical model, i.e. the subordinated Brownian motion, can be inappropriate for the description of observed phenomena that exhibit behavior not adequate for Gaussian systems. Therefore, in this paper we extend the classical approach and replace the Brownian motion by the tempered stable process. Moreover, on the other hand, as an extension of the classical model, we analyze the general class of inverse subordinators. We examine the main properties of the tempered stable process driven by inverse subordinators from the infinitely divisible class of distributions. We show the fractional Fokker–Planck equation of the examined process and the asymptotic behavior of the mean square displacement for two cases of subordinators. Additionally, we examine how an external force can influence the examined characteristics. (paper)

  4. Transport in the spatially tempered, fractional Fokker-Planck equation

    Science.gov (United States)

    Kullberg, A.; del-Castillo-Negrete, D.

    2012-06-01

    A study of truncated Lévy flights in super-diffusive transport in the presence of an external potential is presented. The study is based on the spatially tempered, fractional Fokker-Planck (TFFP) equation in which the fractional diffusion operator is replaced by a tempered fractional diffusion (TFD) operator. We focus on harmonic (quadratic) potentials and periodic potentials with broken spatial symmetry. The main objective is to study the dependence of the steady-state probability density function (PDF), and the current (in the case of periodic potentials) on the level of tempering, ?, and on the order of the fractional derivative in space, ?. An expansion of the TFD operator for large ? is presented, and the corresponding equation for the coarse grained PDF is obtained. The steady-state PDF solution of the TFFP equation for a harmonic potential is computed numerically. In the limit ? ? ?, the PDF approaches the expected Boltzmann distribution. However, nontrivial departures from this distribution are observed for finite (? > 0) truncations, and ? ? 2. In the study of periodic potentials, we use two complementary numerical methods: a finite-difference scheme based on the Grunwald-Letnikov discretization of the truncated fractional derivatives and a Fourier-based spectral method. In the limit ? ? ?, the PDFs converges to the Boltzmann distribution and the current vanishes. However, for ? ? 2, the PDF deviates from the Boltzmann distribution and a finite non-equilibrium ratchet current appears for any ? > 0. The current is observed to converge exponentially in time to the steady-state value. The steady-state current exhibits algebraical decay with ?, as J ˜ ?-?, for ? ? 1.75. However, for ? ? 1.5, the steady-state current decays exponentially with ?, as J ˜ e-??. In the presence of an asymmetry in the TFD operator, the tempering can lead to a current reversal. A detailed numerical study is presented on the dependence of the current on ? and the physical parameters of the system.

  5. Transport in the spatially tempered, fractional Fokker–Planck equation

    International Nuclear Information System (INIS)

    A study of truncated Lévy flights in super-diffusive transport in the presence of an external potential is presented. The study is based on the spatially tempered, fractional Fokker–Planck (TFFP) equation in which the fractional diffusion operator is replaced by a tempered fractional diffusion (TFD) operator. We focus on harmonic (quadratic) potentials and periodic potentials with broken spatial symmetry. The main objective is to study the dependence of the steady-state probability density function (PDF), and the current (in the case of periodic potentials) on the level of tempering, ?, and on the order of the fractional derivative in space, ?. An expansion of the TFD operator for large ? is presented, and the corresponding equation for the coarse grained PDF is obtained. The steady-state PDF solution of the TFFP equation for a harmonic potential is computed numerically. In the limit ? ? ?, the PDF approaches the expected Boltzmann distribution. However, nontrivial departures from this distribution are observed for finite (? > 0) truncations, and ? ? 2. In the study of periodic potentials, we use two complementary numerical methods: a finite-difference scheme based on the Grunwald–Letnikov discretization of the truncated fractional derivatives and a Fourier-based spectral method. In the limit ? ? ?, the PDFs converges to the Boltzmann distribution and the current vanishes. However, for ? ? 2, the PDF deviates from the Boltzmann distribution ann distribution and a finite non-equilibrium ratchet current appears for any ? > 0. The current is observed to converge exponentially in time to the steady-state value. The steady-state current exhibits algebraical decay with ?, as J ? ???, for ? ? 1.75. However, for ? ? 1.5, the steady-state current decays exponentially with ?, as J ? e???. In the presence of an asymmetry in the TFD operator, the tempering can lead to a current reversal. A detailed numerical study is presented on the dependence of the current on ? and the physical parameters of the system. (paper)

  6. Comparison Between Atmospheric Turbidity Coefficients of Desert and Temperate Climates

    OpenAIRE

    Elminir, Hamdy K.; Rahuma, U. A.; Benda, V.

    2001-01-01

    , and Angström turbidity coefficients, b, are calculated from measurements of broadband filters at Helwan, Egypt, which has a desert climate. A linear regression model is to be determined between the Linke factor and the Angström turbidity coefficient. This relation is compared with similar relations reported for a temperate climate [Prague, Czech Republic]. This comparison is made to determine whether a universal relation exists between these two important coefficients, or whether the rela...

  7. Nitrous oxide emission reduction in temperate biochar-amended soils

    OpenAIRE

    Felber, R.; Hu?ppi, R.; Leifeld, J.; Neftel, A.

    2012-01-01

    Biochar, a pyrolysis product of organic residues, is an amendment for agricultural soils to improve soil fertility, sequester CO2 and reduce greenhouse gas (GHG) emissions. In highly weathered tropical soils laboratory incubations of soil-biochar mixtures revealed substantial reductions for nitrous oxide (N2O) and carbon dioxide (CO2). In contrast, evidence is scarce for temperate soils. In a three-factorial laboratory i...

  8. Radioecology of temperate coastal sand dunes: A synthesis

    OpenAIRE

    Wood, M. D.; Beresford, N. A.; Barnett, C.L; Copplestone, D

    2011-01-01

    Temperate coastal sand dunes are amongst the most dynamic landscapes on earth, their evolution being mediated by both climatic and environmental conditions. Formed at the interface between terrestrial and aquatic environments, these biodiversity-rich ecosystems are a valuable resource that deliver a range ecosystem services (the benefits people derive from ecosystems). Sand dune ecosystem services include agricultural products, storm protection through coastal defence, river water purificat...

  9. Within-host competition determines reproductive success of temperate bacteriophages

    OpenAIRE

    Refardt, Dominik

    2011-01-01

    Within-host competition between parasites is frequently invoked as a major force for parasite evolution, yet quantitative studies on its extent in an organismal group are lacking. Temperate bacteriophages are diverse and abundant parasites of bacteria, distinguished by their ability to enter a facultative dormant state in their host. Bacteria can accumulate multiple phages that may eventually abandon dormancy in response to host stress. Host resources are then converted into phage particles, ...

  10. Structural strength of steels with tempered martensite structure

    International Nuclear Information System (INIS)

    Diagram of structural strength for structural steels, plotted in Ksub(IC)-?sub(0.2) coordinates, is presented. It is shown that steels with martensite structure possess low structural strength. Possible methods of increasing structural strength of hardened and low-tempered steels, based on change of real austenite grain composition, size and boundary configuration, are considered. Results of experiments for 40Kh and 45KhN2MFA steels are given

  11. TEM studies of tempered structural steels with Ni

    OpenAIRE

    Pacyna, J.; Ba?a, P.; Krawczyk, J.

    2007-01-01

    Purpose: The reason for writing this paper was to describe the influence of Ni addition on the microstructure of structural steels after tempering. In this investigation, four model alloys of the variable concentration of Ni and constant concentration of carbon and other elements were used.Design/methodology/approach: The alloys were melted in air and hot forged into bars 20×35 mm. The samples for investigations were machined after normalizing. All samples for TEM investigations were used in...

  12. Groundwater flow modelling of periods with temperate climate conditions - Laxemar

    International Nuclear Information System (INIS)

    As a part of the license application for a final repository for spent nuclear fuel at Forsmark, the Swedish Nuclear Fuel and Waste Management Company (SKB) has undertaken a series of groundwater flow modelling studies. These represent time periods with different hydraulic conditions and the simulations carried out contribute to the overall evaluation of the repository design and long-term radiological safety. This report concerns the modelling of a repository at the Laxemar-Simpevarp site during temperate climate conditions as a comparison to corresponding modelling carried out for Forsmark /Joyce et al. 2010/. The collation and implementation of onsite hydrogeological and hydrogeochemical data from previous reports are used in the construction of a Hydrogeological base case (reference case conceptualisation) and then an examination of various areas of uncertainty within the current understanding by a series of model variants. The Hydrogeological base case models at three different scales, 'repository', 'site' and 'regional' make use of a discrete fracture network (DFN) and equivalent continuous porous medium (ECPM) models. The use of hydrogeological models allow for the investigation of the groundwater flow from a deep disposal facility to the biosphere and for the calculation of performance measures that will provide an input to the site performance assessment. The focus of the study described in this report has been to perform numerical simulations of the hydrogeological system from post-closure and throughout the temperate period up until the receding shoreline leaves the modelling domain at around 15,000 AD. Besides providing quantitative results for the immediate temperate period following post-closure, these results are also intended to give a qualitative indication of the evolution of the groundwater system during future temperate periods within an ongoing cycle of glacial/inter-glacial events

  13. Groundwater flow modelling of periods with temperate climate conditions - Laxemar

    Energy Technology Data Exchange (ETDEWEB)

    Joyce, Steven; Simpson, Trevor; Hartley, Lee; Applegate, David; Hoek, Jaap; Jackson, Peter; Roberts, David; Swan, David (Serco Technical Consulting Services (United Kingdom)); Gylling, Bjoern; Marsic, Niko (Kemakta Konsult AB, Stockholm (Sweden)); Rhen, Ingvar (SWECO Environment AB, Falun (Sweden))

    2010-12-15

    As a part of the license application for a final repository for spent nuclear fuel at Forsmark, the Swedish Nuclear Fuel and Waste Management Company (SKB) has undertaken a series of groundwater flow modelling studies. These represent time periods with different hydraulic conditions and the simulations carried out contribute to the overall evaluation of the repository design and long-term radiological safety. This report concerns the modelling of a repository at the Laxemar-Simpevarp site during temperate climate conditions as a comparison to corresponding modelling carried out for Forsmark /Joyce et al. 2010/. The collation and implementation of onsite hydrogeological and hydrogeochemical data from previous reports are used in the construction of a Hydrogeological base case (reference case conceptualisation) and then an examination of various areas of uncertainty within the current understanding by a series of model variants. The Hydrogeological base case models at three different scales, 'repository', 'site' and 'regional' make use of a discrete fracture network (DFN) and equivalent continuous porous medium (ECPM) models. The use of hydrogeological models allow for the investigation of the groundwater flow from a deep disposal facility to the biosphere and for the calculation of performance measures that will provide an input to the site performance assessment. The focus of the study described in this report has been to perform numerical simulations of the hydrogeological system from post-closure and throughout the temperate period up until the receding shoreline leaves the modelling domain at around 15,000 AD. Besides providing quantitative results for the immediate temperate period following post-closure, these results are also intended to give a qualitative indication of the evolution of the groundwater system during future temperate periods within an ongoing cycle of glacial/inter-glacial events

  14. Redistribution of alloying elements during tempering of a nanocrystalline steel

    OpenAIRE

    Garci?a Caballero, Francisca; Miller, M. K.; Garci?a Mateo, Carlos; Capdevila, Carlos; Babu, S. S.

    2008-01-01

    Redistribution of alloying elements during tempering of a novel nanocrystalline steel consisting of a mixture of lower bainitic ferrite and carbon-enriched retained austenite has been analysed by atom probe tomography. Three physical processes, namely redistribution of substitutional solute across the austenite/bainitic ferrite interface before retained austenite decomposition, redistribution of solute across the lower bainite cementite/ferrite interface and the precipitation o...

  15. Parallel Tempering Algorithm for Conformational Studies of Biological Molecules

    CERN Document Server

    Hansmann, Uwe H E

    1997-01-01

    The effectiveness of a new algorithm, parallel tempering, is studied for numerical simulations of biological molecules. These molecules suffer from a rough energy landscape. The resulting slowing down in numerical simulations is overcome by the new method. This is demonstrated by performing simulations with high statistics for one of the simplest peptides, Met-enkephalin. The numerical effectiveness of the new technique was found to be much better than traditional methods and is comparable to sophisticated methods like generalized ensemble techniques.

  16. 33 CFR 100.109 - Winter Harbor Lobster Boat Race, Winter Harbor, ME.

    Science.gov (United States)

    2010-07-01

    ...Winter Harbor Lobster Boat Race, Winter Harbor, ME...Winter Harbor Lobster Boat Race, Winter Harbor, ME...modify, or cancel the race as conditions or circumstances...of this regulation and other applicable laws. ...this section will be in effect the second Sunday...

  17. Britannica Sporting Record: The Winter Games

    Science.gov (United States)

    Encyclopaedia Britannica, Inc.

    Encyclopaedia Britannica's Olympic Winter Games site offers detailed Olympic information and history. Offerings include an overview of the Olympic movement, histories of each of the past seventeen Olympic Winter Games, articles about the events included in the Winter Games, biographies of past competitors, and a searchable Olympic Record database. This well-researched site provides an interesting backdrop for this year's Winter Games in Nagano, Japan.

  18. VI Olympic Winter Games Oslo 1952

    OpenAIRE

    Petersen, Rolf

    2013-01-01

    The official report, “VI Olympic Winter Games Oslo 1952” published by the Organising Committee is quite detailed. It consists of one bilingual English/Norwegian volume. It is thus the first bilingual official report of the Winter Games. Part I: VI Olympic Winter Games Oslo ; Historical ; Installations ; Organising the Games.- Part II: Programme of the Winter Games ; Invitations to the National Olympic Committees ; The torch relay from Morgedal to Oslo.- Part III: The sports events ; Resul...

  19. INDUCTION OF TEMPERATE CYANOPHAGES USING HEAVY METAL - COPPER

    Directory of Open Access Journals (Sweden)

    MAREI E.M.

    2013-09-01

    Full Text Available Presence of prophages in cells of three isolates of Anabaena sp. (Anabaena sp.1, sp.2 and sp.3, Anabaena cylindrica, Nostoc muscorum and Oscillatoria sp. was investigated. Copper sulfate at concentration of 3.1x10-4 M was successfully used for induction of temperate cyanophages. Among the cyanobacterial isolates tested Anabaena cylindrica was found to contain a prophage. A temperate phage was induced from Anabaena cylindrica by copper sulfate treatment and designated Ac-1. The induced phage isolate formed hazy circular plaques of 5 mm in diameter. The thermal inactivation point and longevity in vitro of the induced phage isolate (Ac-1 were found to be 70°C and 36 hrs., respectively. The induced cyanophage particles were examined by transmission electron microscopy. The phage particles were of head and tail type. The head diameter, tail length and tail width were found to be 50 nm, 116.6 nm and 8.3 nm, respectively.Ultrathin sections of infected A. cylindrica cells with temperate cyanophage and healthy ones were examined by electron microscopy. Marked changes in protoplasm and cell membrane, i.e. coagulation of protoplasm, formation of vesicles and vacuoles were observed in the infected cells as compared to the healthy ones. Phage particles were detected inside the infected A. cylindrica cells. Moreover, lysis of cell wall and release of the induced phage particles were also observed.

  20. Winter cover crops influence Amaranthus palmeri establishment

    Science.gov (United States)

    Winter cover crops were evaluated for their effect on Palmer amaranth (PA) suppression in cotton production. Cover crops examined included rye and four winter legumes: narrow-leaf lupine, crimson clover, Austrian winter pea, and cahaba vetch. Each legume was evaluated alone and in a mixture with rye...

  1. Phase transformation and impact properties in the experimentally simulated weld heat-affected zone of a reduced activation ferritic/martensitic steel

    Science.gov (United States)

    Moon, Joonoh; Lee, Chang-Hoon; Lee, Tae-Ho; Jang, Min-Ho; Park, Min-Gu; Han, Heung Nam

    2014-12-01

    In this work, the phase transformation and impact properties in the weld heat-affected zone (HAZ) of a reduced activation ferritic/martensitic (RAFM) steel are investigated. The HAZs were experimentally simulated using a Gleeble simulator. The base steel consisted of tempered martensite through normalizing at 1000 °C and tempering at 750 °C, while the HAZs consisted of martensite, ?-ferrite and a small volume of autotempered martensite. The impact properties using a Charpy V-notch impact test revealed that the HAZs showed poor impact properties due to the formation of martensite and ?-ferrite as compared with the base steel. In addition, the impact properties of the HAZs further deteriorated with an increase in the ?-ferrite fraction caused by increasing the peak temperature. The impact properties of the HAZs could be improved through the formation of tempered martensite after post weld heat treatment (PWHT), but they remained lower than that of the base steel because the ?-ferrite remained in the tempered HAZs.

  2. Second generation sequencing and morphological faecal analysis reveal unexpected foraging behaviour by Myotis nattereri (Chiroptera, Vespertilionidae) in winter

    DEFF Research Database (Denmark)

    Hope, Paul R; Bohmann, Kristine

    2014-01-01

    BACKGROUND: Temperate winters produce extreme energetic challenges for small insectivorous mammals. Some bat species inhabiting locations with mild temperate winters forage during brief inter-torpor normothermic periods of activity. However, the winter diet of bats in mild temperate locations is studied infrequently. Although microscopic analyses of faeces have traditionally been used to characterise bat diet, recently the coupling of PCR with second generation sequencing has offered the potential to further advance our understanding of animal dietary composition and foraging behaviour by allowing identification of a much greater proportion of prey items often with increased taxonomic resolution. We used morphological analysis and Illumina-based second generation sequencing to study the winter diet of Natterer's bat (Myotis nattereri) and compared the results obtained from these two approaches. For the first time, we demonstrate the applicability of the Illumina MiSeq platform as a data generation source for bat dietary analyses. RESULTS: Faecal pellets collected from a hibernation site in southern England during two winters (December-March 2009-10 and 2010-11), indicated that M. nattereri forages throughout winter at least in a location with a mild winter climate. Through morphological analysis, arthropod fragments from seven taxonomic orders were identified. A high proportion of these was non-volant (67.9% of faecal pellets) and unexpectedly included many lepidopteran larvae. Molecular analysis identified 43 prey species from six taxonomic orders and confirmed the frequent presence of lepidopteran species that overwinter as larvae. CONCLUSIONS: The winter diet of M. nattereri is substantially different from other times of the year confirming that this species has a wide and adaptable dietary niche. Comparison of DNA derived from the prey to an extensive reference dataset of potential prey barcode sequences permitted fine scale taxonomic resolution of prey species. The high occurrence of non-volant prey suggests that gleaning allows prey capture at low ambient temperatures when the abundance of flying insects may be substantially reduced. Interesting questions arise as to how M. nattereri might successfully locate and capture some of the non-volant prey species encountered in its faeces. The consumption of lepidopteran larvae such as cutworms suggests that M. nattereri eats agricultural pest species.

  3. Spent nuclear fuel project cold vacuum drying facility tempered water and tempered water cooling system design description

    International Nuclear Information System (INIS)

    This document provides the System Design Description (SDD) for the Cold Vacuum Drying Facility (CVDF) Tempered Water (TW) and Tempered Water Cooling (TWC) System . The SDD was developed in conjunction with HNF-SD-SNF-SAR-002, Safety Analysis Report for the Cold Vacuum Drying Facility, Phase 2, Supporting Installation of Processing Systems (Garvin 1998), The HNF-SD-SNF-DRD-O02, 1998, Cold Vacuum Drying Facility Design Requirements, and the CVDF Design Summary Report. The SDD contains general descriptions of the TW and TWC equipment, the system functions, requirements and interfaces. The SDD provides references for design and fabrication details, operation sequences and maintenance. This SOD has been developed for the SNFP Operations Organization and shall be updated, expanded, and revised in accordance with future design, construction and startup phases of the CVDF until the CVDF final ORR is approved

  4. The possibility of tribopair lifetime extending by welding of quenched and tempered stainless steel with quenched and tempered carbon steel

    Directory of Open Access Journals (Sweden)

    V. Maruši?

    2015-04-01

    Full Text Available In the conditions of tribocorrosion wear, extending of parts lifetime could be achieved by using stainless steel,which is hardened to sufficiently high hardness. In the tribosystem bolt/ bushing shell/link plate of the bucket elevator transporter conveyor machine, the previously quenched and tempered martensitic stainless steel for bolts is hardened at ?47 HRC and welded with the quenched and tempered high yield carbon steel for bolts. Additional material, based on Cr-Ni-Mo (18/8/6 is used. The microstructure and hardness of welded samples are tested. On the tensile tester, resistance of the welded joint is tested with a simulated experiment. Dimensional control of worn tribosystem elements was performed after six months of service.

  5. Tailored tempering. Customized material properties for hot-stamped parts; Tailored Tempering. Massgeschneiderte Werkstoffeigenschaften fuer waermeumgeformte Bauteile

    Energy Technology Data Exchange (ETDEWEB)

    Sikora, Sascha; Banik, Janko; Graff, Stephane; Laurenz, Robert; Lenze, Franz-Josef [ThyssenKrupp Steel Europe AG, Dortmund (Germany). FuE

    2012-07-01

    The requirements placed on vehicle crash performance and fuel consumption have increased consistently in recent years. Technologies such as the press hardening of manganese-boron steels can help reduce car body weight while optimizing service properties. ThyssenKrupp Steel Europe has developed an enhanced press hardening process called 'tailored tempering' that makes it possible to exploit the full range of strength levels offered by steel through precise control of the cooling process in the forming die. (orig.)

  6. Dilatometric and hardness analysis of C45 steel tempering with different heating-up rates

    Directory of Open Access Journals (Sweden)

    A. Kulawik

    2012-01-01

    Full Text Available Modelling of technological processes of heat treatment or welding, involving multiple heat source transitions, requires considering the phenomenon of tempering. In work have been presented results of dilatometric research of hardened C45 steel subjected to tempering. The analysis of the influence of heating rate at the kinetic determined from dilatometric curves has been made. There have also been estimated quantities of transformation expansions and thermal expansion coefficients of hardening and tempering structures (austenite, ferrite, pearlite, martensite and sorbite. The analysis of tempering time influence on the hardness of tempered steel has been made. Functions associating hardness with tempering time (rate of heating-up in technological processes based on short-timed action of a heat source (eg. laser treatment have been suggested.

  7. The kinetics of phase transformations during the tempering of HS6-5-2 steel

    OpenAIRE

    Krawczyk, J.; J. Pacyna; Ba?a, P

    2009-01-01

    Purpose: This work contains a detailed description of the kinetics of phase transformations during tempering of hardened HS6-5-2 high-speed steel. Moreover, the microstructure development in tested samples, reflecting the extend of the phase transformations during tempering, was discussed too.Design/methodology/approach: CHT diagram, illustrating the kinetics of phase transformations during continuous heating (tempering) from as-quenched state of investigated steel, was ...

  8. Behaviour of 4340 steel with respect to low cycle fatigue for different temper temperatures

    International Nuclear Information System (INIS)

    The behaviour of 4340 steel has been studied with respect to low cycle fatigue for the as quenched and tempered condition at temper temperatures of 200decC, 400degC and 600degC. All the tests wre accomplished with strain control at environment temperature. The obtained test results have shown different behaviours for each temper temperature. For all the temperatures a sofftening effect of the material related to the tension test was observed. (Author)

  9. Effect of Tempering and Baking on the Charpy Impact Energy of Hydrogen-Charged 4340 Steel

    Science.gov (United States)

    Mori, K.; Lee, E. W.; Frazier, W. E.; Niji, K.; Battel, G.; Tran, A.; Iriarte, E.; Perez, O.; Ruiz, H.; Choi, T.; Stoyanov, P.; Ogren, J.; Alrashaid, J.; Es-Said, O. S.

    2015-01-01

    Tempered AISI 4340 steel was hydrogen charged and tested for impact energy. It was found that samples tempered above 468 °C (875 °F) and subjected to hydrogen charging exhibited lower impact energy values when compared to uncharged samples. No significant difference between charged and uncharged samples tempered below 468 °C (875 °F) was observed. Neither exposure nor bake time had any significant effect on impact energy within the tested ranges.

  10. Selective recharge and isotopic composition of shallow groundwater within temperate, epigenic carbonate aquifers

    Science.gov (United States)

    Florea, Lee J.

    2013-05-01

    This paper considers the variation of ?18O and ?2H (VSMOW) in precipitation and shallow groundwater from carbonate aquifers that lend insight into the source and timing of recharge within temperate, epigenic karst. The shallow groundwater collected during 2010 and 2011 at Stream Cave (SC) and Natural Bridge Caverns (NBC) represent one input to and the primary output from the Redmond Creek karst aquifer in the Cumberland Plateau of southeast Kentucky, respectively. These data are compared with the isotopic composition of concurrent samples of precipitation from the same watershed that covers some 1900 ha. Values of ?18O and ?2H at SC and NBC are statistically similar and cluster at the midpoint of the local meteoric water line. These values remain surprisingly constant despite seasonal changes in temperature regimens and discharge. Samples in 2012 from regional springs that include Redmond Creek are more depleted in the heavier isotope and similarly stable despite coming from aquifers of a range of sizes and physical characteristics. Applying a Priestly-Taylor model for daily values of potential evapotranspiration, only 43% of the 1.10 m of precipitation in the 2010-2011 dataset remains as potential recharge, primarily during cooler months with lower solar insolation. Weighting ?18O and ?2H values of precipitation by potential recharge creates a better match with the isotopic composition of shallow groundwater than by weighting by precipitation amount. The isotopic composition and deuterium excess of precipitation samples are directly and inversely proportional to temperature, respectively. Deuterium excess in this study and displays intra- and inter-annual variation that ranges from a minimum of +11.1‰ to a maximum of +29.5‰ that demonstrate the higher-than-average deuterium excess in greater Appalachia and the shifting latitude of moisture sources, including a significant winter component of re-evaporated, continental moisture.

  11. Reproductive performance of different breeds of broiler rabbits under sub-temperate climatic conditions

    Directory of Open Access Journals (Sweden)

    D. Kumar

    2013-09-01

    Full Text Available This study was conducted to assess the effect of breed, season, age and weight of doe at mating on reproductive performance of 4 broiler rabbit breeds, Grey Giant, White Giant, Soviet Chinchilla, and New Zealand White, reared under standard management practices in sub-temperate climatic conditions of India. They were first mated at 6 to 7 mo of age, whereupon an extensive breeding system (re-mating after weaning was followed. Weaning was done 42 d after kindling. The data from the records on reproduction consisting of 503 matings and 377 kindlings were analysed. The parameters considered were fertility rate, litter size at birth (LSB, litter weight at birth (LWB, litter size at weaning (LSW, litter weight at weaning (LWW, doe weight at mating (DWM, gestation length and sex ratio. Among 4 breeds, the LSB, LWB and LSW were higher in Grey Giant followed by White Giant, Soviet Chinchilla and New Zealand White. The LSB and LSW in Grey Giant breed differed significantly (P<0.05 from Soviet Chinchilla and New Zealand White. Season had significant (P<0.05 effect on LSW with higher values during spring (5.68±0.24, followed by summer (5.29±0.30, winter (5.13±0.25 and autumn (4.17±0.49. The body weight of doe at service significantly influenced fertility. The fertility increased as body weight increased. The age of the doe at mating had a significant effect on LSW, with higher values for does more than 2 yr and less than 1 yr old compared to 1- to 2-yr old does. The parity did not affect any of the parameters studied. It is concluded that the factors studied affect the reproductive performance of rabbit does. Grey Giant breed showed the highest litter size at birth and weaning, and the highest litter size and weight at weaning was in spring.

  12. Experimental warming does not enhance soil respiration in a semiarid temperate forest-steppe ecosystem

    DEFF Research Database (Denmark)

    Lellei-Kovacs, E.; Kovacs-Lang, E.

    2008-01-01

    The influence of simulated climate change on soil respiration was studied in a field experiment on 4 m x 5 m plots in the semiarid temperate Pannonian sand forest-steppe. This ecosystem type has low productivity and soil organic matter content, and covers large areas, yet data on soil carbon fluxes are still limited. Soil respiration rate-measured monthly between April and November from 2003 to 2006-remained very low (0.09 - 1.53 mu mol CO2 m(-2) s(-1))in accordance with the moderate biological activity and low humus content of the nutrient poor, coarse sandy soil. Specific soil respiration rate ( calculated for unit soil organic matter content), however, was relatively high (0.36 - 7.92 mu mol CO g(-1) C(org)h(-1)) suggesting substrate limitation for soil biological activity. During the day, soil respiration rate was significantly lower at dawn than at midday, while seasonally clear temperature limitation in winter and water limitation in summer were detected. Between years, annual precipitation appeared to be important in determining soil carbon efflux intensity. Nocturnal warming increased soil temperature in 1 cm depth at dawn by 1.6 degrees C on the average, and decreased topsoil (0-11 cm) moisture content by 0.45 vol%. Drought treatment decreased soil moisture content by an average of 0.81 vol%. Soil respiration rate tended to decrease by 7-15% and 13-15% in response to heat and drought treatment, respectively, although the changes were not statistically significant. Nocturnal warming usually prevented dew formation, and that probably also influenced soil respiration. Based on these results, we expect a reduction in the volume and rate of organic matter turnover in this ecosystem in response to the anticipated climate change in the region.

  13. Invasion of Nostocales (cyanobacteria to subtropical and temperate freshwater lakes – Physiological, regional and global driving forces

    Directory of Open Access Journals (Sweden)

    AssafSukenik

    2012-03-01

    Full Text Available Similarly to the increased number of studies on invasive plants and animals in terrestrial and aquatic ecosystems, many reports were recently published on the invasion of Nostocales (cyanobacteria to freshwater environments worldwide. Invasion and proliferation of Nostocales in new habitats have the potential to significantly alter the structure of native community and to modify ecosystem functioning. But most importantly, they influence the water quality due to a variety of toxic compounds that some species produce. Therefore a special attention was given to the invasion and persistence of toxic cyanobacteria in many aquatic ecosystems. Here we summarize the currently published records on the invasion of two Nostocales genera, Cylindrospermopsis and Aphanizomenon, to lakes and water reservoirs in subtropical and temperate zones. These invading species possess traits thought to be common to many invasive organisms: high growth rate, high resource utilization efficiency and overall superior competitive abilities over native species when local conditions vary. Assuming that dispersion routes of cyanobacteria have not been changed much in recent decades, their recent establishment and proliferation in new habitats indicate changes in the environment under which they can exploit their physiological advantage over the native phytoplankton population. In many cases global warming was identified as the major driving force for the invasion of Nostocales. Due to this uncontrollable trend, invasive Nostocales species are expected to maintain their presence in new habitats and further expand to new environments. In other cases regional changes in nutrient loads and in biotic conditions were attributed to the invasion events

  14. Foraging flight distances of wintering ducks and geese: a review

    Directory of Open Access Journals (Sweden)

    William P. Johnson

    2014-12-01

    Full Text Available The distance covered by foraging animals, especially those that radiate from a central area when foraging, may affect ecosystem, community, and population dynamics, and has conservation and landscape planning implications for multiple taxa, including migratory waterfowl. Migrating and wintering waterfowl make regular foraging flights between roosting and feeding areas that can greatly impact energetic resources within the foraging zone near roost sites. We reviewed published studies and gray literature for one-way foraging flight distances (FFDs of migrating and wintering dabbling ducks and geese. Thirty reviewed studies reported FFDs and several reported values for multiple species or locations. We obtained FFD values for migration (n = 7 and winter (n = 70. We evaluated the effects of body mass, guild, i.e., dabbling duck or goose, and location, i.e., Nearctic or Palearctic, on FFDs. We used the second-order Akaike's Information Criterion for model selection. We found support for effects of location and guild on FFDs. FFDs of waterfowl wintering in the Nearctic (7.4 ± 6.7 km, mean ± SD; n = 39 values were longer than in the Palearctic (4.2 ± 3.2 km; n = 31 values. The FFDs of geese (7.8 ± 7.2 km, mean ± SD; n = 24 values were longer than FFDs of dabbling ducks (5.1 ± 4.4 km, mean ± SD; n = 46 values. We found mixed evidence that distance flown from the roost changed, i.e., increased or decreased, seasonally. Our results can be used to refine estimates of energetic carrying capacity around roosts and in biological and landscape planning efforts.

  15. Effect of simulated fall heat waves on cold hardiness and winter survival of hemlock looper, Lambdina fiscellaria (Lepidoptera: Geometridae).

    Science.gov (United States)

    Vallières, Rosemarie; Rochefort, Sophie; Berthiaume, Richard; Hébert, Christian; Bauce, Éric

    2015-02-01

    The hemlock looper (Lambdina fiscellaria) is an important pest of eastern Canadian forests. The ongoing climate warming could modify the seasonal ecology of this univoltine species that lays eggs at the end of summer and overwinters at this stage. Indeed, the increase in frequency and intensity of extreme climatic events such as fall heat waves could interfere with the winter metabolism of the hemlock looper. Moreover, the host plant quality, which influences the quantity of insect energetic reserves, the geographic origin of populations and the conditions prevailing during the cold acclimation period, could cause various responses of this pest to climate warming. The main objective of this study is to determine the impact of these factors on hemlock looper winter biology. In October 2010, hemlock looper eggs initially collected from two geographic areas in the province of Québec, and from parents reared on two host plants, were exposed to fall heat waves of different intensities during 5 consecutive days. Supercooling points and cryoprotectant levels were measured on eggs on four different dates in 2010-2011 and survival rate was measured in April 2011. Our results show that hemlock looper eggs have a very low supercooling point and high levels of trehalose, glucose and mannitol in September and November. However, there is no clear relationship between the concentration of these compounds and the decrease in supercooling points. Contents in trehalose, glucose and mannitol were significantly influenced by fall heat waves and by the origin of the population. Winter survival of eggs from the temperate population was negatively affected by strong heat waves while the boreal population was not affected. This study suggests that the metabolism and winter survival of temperate hemlock looper populations in Québec will be more affected by fall heat waves that will increase in frequency due to climate change, than boreal populations. PMID:25585353

  16. Comparative analysis of radiosensitivity of fish eggs from northern and temperate climate

    International Nuclear Information System (INIS)

    In the radiobiological studies of aquatic organisms, fish eggs are the favorite subject for experimental work because of easy availability of embryos and the possibility of observing the development of embryos within eggs. Data from Russian/FSU publications concerning the effects of ionizing radiation on fish eggs were compiled in the EPIC database within the framework of the EC Project EPIC. The comparative analysis of radiosensitivity was performed for eggs of two representative fish species from different climatic zones: cold water salmon (Salmo salar), and pike (Esox lucius), a widespread predatory fish in the temperate climate. A special attention was given to data of chronic exposure experiments with incubation of roe in water containing radionuclides. Dose rates on the fish eggs were estimated using appropriate dosimetric methodologies. Dose-effects relationships were constructed for chronic exposures during the periods of fish eggs development. The comparative analysis revealed that effects of ionizing radiation on salmon eggs appeared at lower doses than the effects on pike eggs. For example, first effects on survival of salmon eggs appeared at dose rate (1-2)*10-4 Gy/day, whereas effects on survival of pike eggs were not found at dose rates lower than (5-10)*10-3 Gy/day (chronic exposure); practically total death of roe took place at the chronic dose rates 0.13-0.33 Gy/day for salmon and 0.94 Gy/day for pike. Data on dose-effects relationships for salmon and pike roe defined the range of radiosensitivities between fish species from zones of severe and moderate climate. (author)

  17. Effect of tempering on the toughness of a Cr- Mo bainitic steel

    Science.gov (United States)

    Nasreldin, A. M.; Ghoneim, M. M.; Hammad, F. H.; Klueh, R. L.; Nanstad, R. K.

    1993-06-01

    The effect of tempering on impact and fracture toughness properties of a Cr-Mo bainitic steel was studied in the quenched and stress relieved (Q & SR) condition. The lowest tempering parameter used resulted in considerable improvement in impact properties. Further tempering increased the upper shelf energy, had a minor effect on the transition temperature, and increased both the initiation fracture toughness (JIC) and the tearing modulus (T). However, the effect on JIC and T was much greater than the effect on the impact upper shelf energy. The results were discussed in light of the changes in microstructure and flow properties due to tempering.

  18. Standardized precipitation index zones for Mexico

    Energy Technology Data Exchange (ETDEWEB)

    Giddings, L.; Soto, M. [Instituto de Ecologia, A.C., Xalapa, Veracruz (Mexico); Rutherford, B.M.; Maarouf, A. [Faculty of Environmental Studies, York University, Toronto, Ontario (Canada)

    2005-01-01

    Precipitation zone systems exists for Mexico based on seasonality, quantity of precipitation, climates and geographical divisions, but none are convenient for the study of the relation of precipitation with phenomena such as El nino. An empirical set of seven exclusively Mexican and six shared zones was derived from three series of Standardized Precipitation Index (SPI) images, from 1940 through 1989: a whole year series (SPI-12) of 582 monthly images, a six month series (SPI-6) of 50 images for winter months (November through April), and a six month series (SPI-6) of 50 images for summer months (May through October). By examination of principal component and unsupervised classification images, it was found that all three series had similar zones. A set of basic training fields chosen from the principal component images was used to classify all three series. The resulting thirteen zones, presented in this article, were found to be approximately similar, varying principally at zones edges. A set of simple zones defined by just a few vertices can be used for practical operations. In general the SPI zones are homogeneous, with almost no mixture of zones and few outliers of one zone in the area of others. They are compared with a previously published map of climatic regions. Potential applications for SPI zones are discussed. [Spanish] Existen varios sistemas de zonificacion de Mexico basados en la estacionalidad, cantidad de precipitacion, climas y divisiones geograficas, pero ninguno es conveniente para el estudio de la relacion de la precipitacion con fenomenos tales como El Nino. En este trabajo se presenta un conjunto de siete zonas empiricas exclusivamente mexicanas y seis compartidas, derivadas de tres series de imagenes de SPI (Indice Estandarizado de la Precipitacion), desde 1940 a 1989: una serie de 582 imagenes mensuales (SPI-12), una series de 50 imagenes (SPI-6) de meses de invierno (noviembre a abril), y otra de 50 imagenes (SPI-6) de meses de verano (mayo a octubre). Al examinar imagenes de componentes principales y de clasificaciones no supervisadas, se descubrio que las tres series tenian una zonificacion similar. Un conjunto de campos de entrenamiento fue utilizado para clasificar las tres series. Despues de doce tanteos las zonas resultantes, presentadas aqui, fueron casi identicas para las tres series, con variaciones principalmente alrededor de los bordes. Un conjunto de zonas sencillas definidas por pocos vertices puede ser usado para operaciones practicas. En general, las zonas son homogeneas, casi sin mezcla de zonas y con pocos fragmentos de una zona en otra. Estas zonas se comparan con un mapa previamente publicado de zonas climaticas. Se mencionan posibles aplicaciones.

  19. Standardized Precipitation Index Zones for México

    Scientific Electronic Library Online (English)

    L., GIDDINGS; M., SOTO; B. M., RUTHERFORD; A., MAAROUF.

    2005-01-01

    Full Text Available Existen varios sistemas de zonificación de México basados en la estacionalidad, cantidad de precipitación, climas y divisiones geográficas, pero ninguno es conveniente para el estudio de la relación de la precipitación con fenómenos tales como El Niño. En este trabajo se presenta un conjunto de siet [...] e zonas empíricas exclusivamente mexicanas y seis compartidas, derivadas de tres series de imágenes de SPI (Índice Estandarizado de la Precipitación), desde 1940 a 1989: una serie de 582 imágenes mensuales (SPI-12), una serie de 50 imágenes (SPI-6) de meses de invierno (noviembre a abril), y otra de 50 imágenes (SPI-6) de meses de verano (mayo a octubre). Al examinar imágenes de componentes principales y de clasificaciones no supervisadas, se descubrió que las tres series tenían una zonificación similar. Un conjunto de campos de entrenamiento fue utilizado para clasificar las tres series. Después de doce tanteos las zonas resultantes, presentadas aquí, fueron casi idénticas para las tres series, con variaciones principalmente alrededor de los bordes. Un conjunto de zonas sencillas definidas por pocos vértices puede ser usado para operaciones prácticas. En general, las zonas son homogéneas, casi sin mezcla de zonas y con pocos fragmentos de una zona en otra. Estas zonas se comparan con un mapa previamente publicado de zonas climáticas. Se mencionan posibles aplicaciones. Abstract in english Precipitation zone systems exist for México based on seasonality, quantity of precipitation, climates and geographical divisions, but none are convenient for the study of the relation of precipitation with phenomena such as El Niño. An empirical set of seven exclusively Mexican and six shared zones [...] was derived from three series of Standardized Precipitation Index (SPI) images, from 1940 through 1989: a whole-year series (SPI-12) of 582 monthly images, a six month series (SPI-6) of 50 images for winter months (November through April), and a six-month series (SPI-6) of 50 images for summer months (May through October). By examination of principal component and unsupervised classification images, it was found that all three series had similar zones. A set of basic training fields chosen from the principal component images was used to classify all three series. The resulting thirteen zones, presented in this article, were found to be approximately similar, varying principally at zone edges. A set of simple zones defined by just a few vertices can be used for practical operations. In general the SPI zones are homogeneous, with almost no mixture of zones and few outliers of one zone in the area of others. They are compared with a previously published map of climatic regions. Potential applications for SPI zones are discussed

  20. Zone Refining by Laser

    Science.gov (United States)

    Griner, D. B.

    1986-01-01

    System developed for studying use of laser beam for zone-refining semiconductors and metals. Specimen scanned with focused CO2 laser beam in such way that thin zone of molten material moves along specimen sweeps impurities with it. Zone-melting system comprises microcomputer, laser, electromechanical and optical components for beam control, vacuum chamber that holds specimen, and sensor for determining specimen temperature.

  1. Comparison of produced water toxicity to Arctic and temperate species.

    Science.gov (United States)

    Camus, L; Brooks, S; Geraudie, P; Hjorth, M; Nahrgang, J; Olsen, G H; Smit, M G D

    2015-03-01

    Produced water is the main discharge stream from oil and gas production. For offshore activities this water is usually discharged to the marine environment. Produced water contains traces of hydrocarbons such as polycyclic aromatic hydrocarbons as well as alkylphenols, which are relatively resistant to biodegradation and have been reported to cause adverse effects to marine organisms in laboratory studies. For management of produced water, risk-based tools have been developed using toxicity data for mainly non-Arctic species. Reliable risk assessment approaches for Arctic environments are requested to manage potential impacts of produced water associated with increased oil and gas activities in Arctic regions. In order to assess the applicability of existing risk tools for Arctic areas, basic knowledge on the sensitivity of Arctic species has to be developed. In the present study, acute and chronic toxicity of artificial produced water for 6 Arctic and 6 temperate species was experimentally tested and evaluated. The hazardous concentrations affecting 5% and 50% of the species were calculated from species sensitivity distribution curves. Hazardous concentrations were compared to elucidate whether temperate toxicity data used in risk assessment are sufficiently representative for Arctic species. From the study it can be concluded that hazardous concentration derived from individual species' toxicity data of temperate and Arctic species are comparable. However, the manner in which Arctic and non-Arctic populations and communities respond to exposure levels above established thresholds remains to be investigated. Hence, responses at higher levels of biological organization should be studied to reveal potential differences in sensitivities to produced water between Arctic and non-Arctic ecosystems. PMID:25521339

  2. Laser beam welding tempered 300M ultrahigh mechanical strength steel

    OpenAIRE

    Sheila Medeiros de Carvalho; Milton Sérgio Fernandes de Lima

    2012-01-01

    AISI 300M ultrahigh strength steel has been used in a number of high demanding applications, such as the VLS Brazilian rocket project. This work intends to propose laser beam welding, with subsequent tempering, as a possible route for the fabrication of engineering pieces of this steel. A 2 kW fiber laser was used to produce welded coupons for metallographic, hardness and tensile strength tests. It has been shown that convenient laser parameters for a 3 mm thick plate are 50 mm/s welding spee...

  3. The Research and Application of Webpage Temper-proofing System

    Directory of Open Access Journals (Sweden)

    Wang Yongquan

    2012-06-01

    Full Text Available With the sharp increase of hacking attacks over the last couple of years, web application security has become a key concern. The attack to websites, especially the explosion of webpage interpolating incidents has becomeone of the most serious problems of it. In this paper, the system adopts Web server core embedded technology to imbed tamper detection module and application protection module into the Web server, define correspondingstrategies for temper-proofing, and realize the real-time monitoring and protection of web pages and the dynamic content in databases.

  4. Joints in Tempered Glass Using Glass Dowel Discs

    DEFF Research Database (Denmark)

    Nielsen, Jens Henrik; Poulsen, Peter Noe

    One of the major reasons for using glass in structures is its transparency; however, traditional mechanical joints such as friction joints and steel dowel pinned connections are compromising the transparency. The present paper describes a novel joint which is practically maintaining the complete transparency of the glass. This is achieved by using a dowel disc made entirely of tempered glass. The concept of the joint is proved by pilot tests and numerical models. From the work it is seen that the load-carrying capacity of such a connection is similar to what is found for traditionally in-plane loaded steel dowel pinned joints.

  5. Tempering of hard mixture of bainitic ferrite and austenite

    OpenAIRE

    Garci?a Mateo, Carlos; Peet, M.; Garci?a Caballero, Francisca; Bhadeshia, H. K. D. H.

    2004-01-01

    Recent work has shown that bainitic ferrite plates produced by transformation at low temperatures can be as thin as 20 nm with a hardness in excess of 650 HV30, tensile strength 2.3 GPa and toughness 30 MPa m1/2. Because these properties rely on the fine scale of the microstructure, a study has been carried out in relation to the tempering resistance of steel over the temperature range 350–750ºC. It is found that significant softening occurs only after the plates of ferrite beg...

  6. Main zones of the intertidal zone

    Science.gov (United States)

    Katie Hale (CSUF; Biological Sciences)

    2007-06-08

    The intertidal zone is found where the tides rise and fall daily, alternatively submerging and exposing the shore to ocean water. Organisms must be able to tolerate times of intense sunlight, little moisture, and wave forces.

  7. Main zones of the intertidal zone

    Science.gov (United States)

    Katie Hale (California State University, Fullerton; Student, Biological Sciences)

    2007-01-04

    The intertidal zone is found where the tides rise and fall daily, alternatively submerging and exposing the shore to ocean water. Organisms must be able to tolerate times of intense sunlight, little moisture, and wave forces.

  8. Does a temperate ungulate that breeds in summer exhibit rut-induced hypophagia? Analysis of time budgets of male takin (Budorcas taxicolor) in Sichuan, China.

    Science.gov (United States)

    Guan, Tian Pei; Ge, Bao Ming; Powell, David M; McShea, William J; Li, Sheng; Song, Yan Ling

    2012-03-01

    Mammals maximize fitness by optimizing time and energy allocation between reproduction and survival. Describing time budgets is a way to understand a species' constraints in energy allocation. We describe a time budget for male takin (Budorcas taxicolor) in Tangjiahe Nature Reserve, China, to better understand rut-induced hypophagia, which is frequently observed in temperate ungulates that breed in autumn or in winter. Observations generally occurred at two elevations (1200-1600m and 2600-3200m), using 20-min focal animal scan sampling from 2007 to 2009. Feeding behaviors accounted for the majority in takin's time budget (61.1%) during daylight hours, relative to the other observed behaviors, such as rest (14.1%), alert behavior (10.2%) and locomotion (6.8%). We found a negative correlation between feeding behavior and rutting behavior during the rutting season. A ratio of feeding time to resting time increased from pre-rut to rut, while resting behavior did not change significantly across seasons. These results suggest the "energy saving" hypothesis could explain reduced foraging in male takin during the rut, but aspects of the species biology suggest that hypotheses for rut-induced hypophagia developed for other temperate ungulates do not apply to takin. We suggest that the unusual summer rutting season of takin releases males from the energy constraints encountered by temperate ungulates that breed in the autumn and has other benefits for offspring survival. Further research should be conducted on ungulates that exhibit rut during the summer and tropical ungulates that might not experience limited food availability following the mating season to improve our understanding on rut-induced hypophagia. PMID:22248568

  9. Effects of elevated atmospheric CO2, prolonged summer drought and temperature increase on N2O and CH4 fluxes in a temperate heathland

    DEFF Research Database (Denmark)

    Carter, Mette Sustmann; Ambus, Per

    2011-01-01

    In temperate regions, climate change is predicted to increase annual mean temperature and intensify the duration and frequency of summer droughts, which together with elevated atmospheric carbon dioxide (CO2) concentrations, may affect the exchange of nitrous oxide (N2O) and methane (CH4) between terrestrial ecosystems and the atmosphere. We report results from the CLIMAITE experiment, where the effects of these three climate change parameters were investigated solely and in all combinations in a temperate heathland. Field measurements of N2O and CH4 fluxes took place 1–2 years after the climate change manipulations were initiated. The soil was generally a net sink for atmospheric CH4. Elevated temperature (T) increased the CH4 uptake by on average 10 ?g C m?2 h?1, corresponding to a rise in the uptake rate of about 20%. However, during winter elevated CO2 (CO2) reduced the CH4 uptake, which outweighed the positive effect of warming when analyzed across the study period. Emissions of N2O were generally low (

  10. Mercury in wintering seabirds, an aggravating factor to winter wrecks?

    Science.gov (United States)

    Fort, Jérôme; Lacoue-Labarthe, Thomas; Nguyen, Hanh Linh; Boué, Amélie; Spitz, Jérôme; Bustamante, Paco

    2015-09-15

    Every year, thousands of seabirds are cast ashore and are found dead along the coasts of North America and Western Europe. These massive mortality events called 'winter wrecks' have generally been attributed to harsh climatic conditions and prolonged storms which affect bird energy balance and impact their body condition. Nevertheless, additional stress factors, such as contaminant body burden, could potentially cumulate to energy constraints and actively contribute to winter wrecks. However, the role played by these additional factors in seabird massive winter mortality has received little attention to date. In February/March 2014, an unprecedented seabird wreck occurred along the Atlantic French coasts during which >43,000 seabirds were found dead. By analyzing mercury (Hg) concentrations in various tissues collected on stranded birds, we tested the hypothesis that Hg played a significant role in this mortality. More specifically, we aimed to (1) describe Hg contamination in wintering seabirds found along the French coasts in 2014, and (2) determine if Hg concentrations measured in some vital organs such as kidney and brain reached toxicity thresholds that could have led to deleterious effects and to an enhanced mortality. We found some of the highest Hg levels ever reported in Atlantic puffins, common guillemots, razorbills and kittiwakes. Measured concentrations ranged from 0.8 to 3.6?g·g(-1) of dry weight in brain, 1.3 to 7.2?g·g(-1) in muscle, 2.5 to 13.5?g·g(-1) in kidney, 2.9 to 18.6?g·g(-1) in blood and from 3.1 to 19.5?g·g(-1) in liver. Hg concentrations in liver and brain were generally below the estimated acute toxicity levels. However, kidney concentrations were not different than those measured in the liver, and above levels associated to renal sub-lethal effects, suggesting a potential Hg poisoning. We concluded that although Hg was not directly responsible for the high observed mortality, it has been a major aggravating stress factor for emaciated birds already on the edge. Importantly, this study also demonstrated that total blood, which can be non-lethally collected in seabirds, can be used as a predictor of Hg contamination in other tissues. PMID:25984703

  11. Nitrous oxide emission reduction in temperate biochar-amended soils

    Directory of Open Access Journals (Sweden)

    R. Felber

    2012-01-01

    Full Text Available Biochar, a pyrolysis product of organic residues, is an amendment for agricultural soils to improve soil fertility, sequester CO2 and reduce greenhouse gas (GHG emissions. In highly weathered tropical soils laboratory incubations of soil-biochar mixtures revealed substantial reductions for nitrous oxide (N2O and carbon dioxide (CO2. In contrast, evidence is scarce for temperate soils. In a three-factorial laboratory incubation experiment two different temperate agricultural soils were amended with green waste and coffee grounds biochar. N2O and CO2 emissions were measured at the beginning and end of a three month incubation. The experiments were conducted under three different conditions (no additional nutrients, glucose addition, and nitrate and glucose addition representing different field conditions. We found mean N2O emission reductions of 60 % compared to soils without addition of biochar. The reduction depended on biochar type and soil type as well as on the age of the samples. CO2 emissions were slightly reduced, too. NO3 but not NH4+ concentrations were significantly reduced shortly after biochar incorporation. Despite the highly significant suppression of N2O emissions biochar effects should not be transferred one-to-one to field conditions but need to be tested accordingly.

  12. Comparison Between Atmospheric Turbidity Coefficients of Desert and Temperate Climates

    Directory of Open Access Journals (Sweden)

    Hamdy K. Elminir

    2001-01-01

    Full Text Available Knowledge of the solar radiation available on the earth’s surface is essential for the development of solar energy devices and for estimating of their performance efficiencies. For this purpose it is helpful to study the attenuation of direct normal irradiance by the atmosphere, in terms of fundamental quantities, including optical thickness, relative optical air mass, water vapor content, and aerosol amount. In the present article, we will not deal with cloudy atmospheres because of their great variability in space and time, but will focus our attention on atmospheres characterized by the complete absence of condensed water. The objectives of this article are to report data on aerosol optical depth and atmospheric turbidity coefficients for a desert climate, and to compare them with those of a temperate climate. Aerosol optical depth, the Linke turbidity factor, TL, and ngström turbidity coefficients, _, are calculated from measurements of broadband filters at Helwan, Egypt, which has a desert climate. A linear regression model is to be determined between the Linke factor and the ngström turbidity coefficient. This relation is compared with similar relations reported for a temperate climate [Prague, Czech Republic]. This comparison is made to determine whether a universal relation exists between these two important coefficients, or whether the relation is location dependent.

  13. Population differentiation of temperate amphibians in unpredictable environments.

    Science.gov (United States)

    Chan, Lauren M; Zamudio, Kelly R

    2009-08-01

    Amphibians are a globally distributed and diverse lineage, but much of our current understanding of their population genetic structure comes from studies in mesic temperate habitats. We characterize the population genetic structure of two sympatric explosive breeding amphibians in the southwestern deserts of the United States: the Great Plains toad (Anaxyrus cognatus) and Couch's spadefoot toad (Scaphiopus couchii). For both species, we find limited genetic differentiation even between populations in adjacent valleys separated by dispersal barriers such as mountainous habitats. To understand how population genetic patterns in these two arid-adapted species compare to taxa in more mesic environments, we computed a standardized measure of population differentiation for A. cognatus, S. couchii, and for pond-breeding amphibians that inhabit mesic temperate environments. Our results indicate that the arid-adapted species have lower population genetic structure at fine and moderate scales than most other amphibian species we surveyed. We hypothesize that stochasticity in the availability of appropriate breeding sites as well as landscape homogeneity may result in increased population connectivity in desert-adapted frogs. Future work examining fine-scale population structure in amphibians from a diversity of habitats will test the generality of our findings. Intraspecific comparisons among localities with varied seasonality and habitats will be particularly useful for investigating the interaction between species-typical population dynamics and environmental characteristics as determinants of population connectivity in pond-breeding amphibians. PMID:19573030

  14. An Inventory of Terrestrial Mammals at National Parks in the Northeast Temperate Network and Sagamore Hill National Historic Site

    Science.gov (United States)

    Gilbert, A.T.; O'Connell, A.F., Jr.; Annand, E.M.; Talancy, N.W.; Sauer, J.R.; Nichols, J.D.

    2008-01-01

    An inventory of mammals was conducted during 2004 at nine national park sites in the Northeast Temperate Network (NETN): Acadia National Park (NP), Marsh-Billings-Rockefeller National Historical Park (NHP), Minute Man NHP, Morristown NHP, Roosevelt-Vanderbilt National Historic Site (NHS), Saint-Gaudens NHS, Saugus Iron Works NHS, Saratoga NHP, and Weir Farm NHS. Sagamore Hill NHS, part of the Northeast Coastal and Barrier Network (NCBN), was also surveyed. Each park except Acadia NP was sampled twice, once in the winter/spring and again in the summer/fall. During the winter/spring visit, indirect measure (IM) sampling arrays were employed at 2 to 16 stations and included sampling by remote cameras, cubby boxes (covered trackplates), and hair traps. IM stations were established and re-used during the summer/fall sampling period. Trapping was conducted at 2 to 12 stations at all parks except Acadia NP during the summer/fall period and consisted of arrays of small-mammal traps, squirrel-sized live traps, and some fox-sized live traps. We used estimation-based procedures and probabilistic sampling techniques to design this inventory. A total of 38 species was detected by IM sampling, trapping, and field observations. Species diversity (number of species) varied among parks, ranging from 8 to 24, with Minute Man NHP having the most species detected. Raccoon (Procyon lotor), Virginia Opossum (Didelphis virginiana), Fisher (Martes pennanti), and Domestic Cat (Felis silvestris) were the most common medium-sized mammals detected in this study and White-footed Mouse (Peromyscus leucopus), Northern Short-tailed Shrew (Blarina brevicauda), Deer Mouse (P. maniculatus), and Meadow Vole (Microtus pennsylvanicus) the most common small mammals detected. All species detected are considered fairly common throughout their range including the Fisher, which has been reintroduced in several New England states. We did not detect any state or federal endangered or threatened species.

  15. Multi-proxy summer and winter precipitation reconstruction for southern Africa over the last 200 years

    Science.gov (United States)

    Neukom, Raphael; Nash, David J.; Endfield, Georgina H.; Grab, Stefan W.; Grove, Craig A.; Kelso, Clare; Vogel, Coleen H.; Zinke, Jens

    2014-05-01

    This study presents the first consolidation of palaeoclimate proxy records from multiple archives to develop statistical rainfall reconstructions for southern Africa covering the last two centuries. State-of-the-art ensemble reconstructions reveal multi-decadal rainfall variability in the summer and winter rainfall zones. A decrease in precipitation amount over time is identified in the summer rainfall zone. No significant change in precipitation amount occurred in the winter rainfall zone, but rainfall variability has increased over time. Generally synchronous rainfall fluctuations between the two zones are identified on decadal scales, with common wet (dry) periods reconstructed around 1890 (1930). A strong relationship between seasonal rainfall and sea surface temperatures (SSTs) in the surrounding oceans is confirmed. Coherence among decadal-scale fluctuations of southern African rainfall, regional SST, SSTs in the Pacific Ocean and rainfall in south-eastern Australia suggest SST-rainfall teleconnections across the southern hemisphere. Temporal breakdowns of the SST-rainfall relationship in the southern African regions and the connection between the two rainfall zones are observed, for example during the 1950s. Our results confirm the complex interplay between large-scale teleconnections, regional SSTs and local effects in modulating multi-decadal southern African rainfall variability over long timescales.

  16. Exposure of Trucking Company Workers to Particulate Matter during the Winter

    OpenAIRE

    Lee, Byeong-kyu; Smith, Thomas J.; Garshick, Eric; Natkin, Jonathan; Reaser, Paul; Lane, Kevin; Lee, Haengah Kim

    2005-01-01

    This study analyzed the workplace area concentrations and the personal exposure concentrations to fine particulate (PM2.5), elemental carbon (EC), and organic carbon (OC) measured during the winter period in trucking companies. The averaged personal exposure concentrations at breathing zones of workers are much greater than those of the microenvironment concentrations. The highest difference between the area (microenvironment) and personal exposure concentrations was in the PM2.5 concentratio...

  17. Temperate Ice Depth Sounding Radar (TIDSoR)

    Science.gov (United States)

    Jara, V.; Player, K.; Gogineni, S.; Rodriguez, F.; Thompson, L.

    2007-12-01

    Glaciers in several parts of the world are reported to be retreating and thinning rapidly over the last few years. A key variable in the study of glacier dynamics is ice thickness. A few attempts have been made to develop airborne sounding radars for temperate-ice thickness measurements [Arcone et al., 2000]. There is an urgent need for compact radar for routine ice thickness measurements from ground-based and airborne platforms. Radars (Radio Detection and Ranging) have been widely used to measure ice thickness in Greenland and Antarctica. However, the radars used in these areas operate in the VHF and UHF part of the electromagnetic spectrum. Due to the composition of temperate ice, the attenuation and back-scatter from large pockets of water makes UHF and VHF ineffective in sounding of its thickness. Radars operating in lower part of the HF spectrum are required for sounding temperate ice. We are designing and developing a Temperate Ice Depth-Sounding Radar (TIDSoR) that can penetrate through the water pockets and provide a more accurate measurement of the ice thickness. TIDSoR is a light-weight system for ground-based operations in mountainous terrain or aerial surveys in which weight is an important factor, such as in an UAV. TIDSoR operates on two channels in the HF spectrum using two-linear, frequency-modulated chirp waveforms. The two chirp frequency ranges are 7 to 8 MHz and 13.5 to 14.5 MHz. The radar will operate from a 12-V battery and is designed to weigh less than 2 kg, excluding the battery. The radar consists of three main sections: Digital, RF and antenna. The digital-section generates the transmitter waveforms, timing and control signals, and digitizes processes and stores the received signal. The RF-section consists of a transmitter with a 20-W peak-power amplifier, band-pass filters, and a switching system for a shared antenna. The receiver consists of a blanking switch, a limiter, a low-noise amplifier, a band-pass filter and a data acquisition system to store the acquired data. At HF, a physically large-antenna is needed. TIDSoR takes advantage of the helix antenna concept to minimize its physical dimensions and weight. Moreover, the ability to achieve different polarizations (linear, circular and elliptical) was considered to maximize the performance of the radar system. Arcone, S. A., Lawson, D. E., Moran, M. and Delaney, A. J., 2000, 12-100-MHz profiles of ice depth and stratigraphy of three temperate glaciers. In: Proc. GPR 2000, Eighth Intl. Conf. Ground-Penetrating Radar, Gold Coast, Austral., 23-26 May, 2000.

  18. On microstructure and performance of tempered high-boron high-speed steel roll

    Directory of Open Access Journals (Sweden)

    Fu Hanguang

    2012-08-01

    Full Text Available Influences of the tempering temperature on the microstructure, mechanical property and wear resistance of High-Boron High Speed Steel (HBHSS roll materials were investigated by means of optical microscopy, scanning electron microscopy (SEM, X-ray diffraction, hardness measurement, impact tester, tensile tester and pin abrasion tester. The results show that the as-cast structure of HBHSS consists of a great amount of martensite and M2(B,C and a few retained austenites and M23(B,C6. After solution treated at 1,050 °C and followed by oil cooling, the amount of M23(B,C6 carbo-borides in quenched HBHSS increases obviously and the macrohardness of the quenched HBHSS is 66 HRC, which is very close to the 65.8 HRC of as-cast HBHSS. On the whole, the hardness of HBHSS alloy shows a trend of slight decrease with increasing tempering temperature when tempered below 500 °C. While when above 500 °C, the hardness increases slightly as the tempering temperature increases and reaches a peak at 525 °C and then decreases obviously. The impact toughness of HBHSS has a tendency to increase as the tempering temperature increases. Tempering can improve the tensile strength and elongation of HBHSS, but a higher tempering temperature causes a slight decrease in both tensile strength and elongation. Excellent wear resistance can be obtained by tempering at 500 to 550 °C.

  19. Impurity effect on tendency to temper brittleness in heat resistant Cr-Mo-V steel

    International Nuclear Information System (INIS)

    Effect of sulfur-, phosphorus-, copper-, arsenic-, autimony-, tin impurities on temper brittleness in 25Kh1M1F steel of 18 compositions has beep investigated. It is concluded that only phospohorus and antimony influence noticeably on tendency to temper brittleness in fine-grained steel, at the same time influence of phosphorus is much greater

  20. Temperate carbonate cycling and water mass properties from intertidal to bathyal depths (Azores, N-Atlantic

    Directory of Open Access Journals (Sweden)

    M. Wisshak

    2010-05-01

    Full Text Available The rugged submarine topography of the Azores supports a diverse heterozoan association resulting in intense biotically-controlled carbonate production and accumulation. In order to characterise this cold-water (C factory a 2-year experiment was carried out to study the biodiversity of hardground communities and for budgeting carbonate production and degradation along a bathymetrical transect from the intertidal to bathyal 500 m depth.

    Seasonal temperatures peak in September (above a thermocline and bottom in March (stratification diminishes with a decrease in amplitude and absolute values with depth, and with tidal-driven short-term fluctuations. Measured seawater stable isotope ratios and levels of dissolved nutrients decrease with depth, as do the calcium carbonate saturation states. The photosynthetic active radiation shows a base of the euphotic zone in ~70 m and a dysphotic limit in ~150 m depth.

    Bioerosion, being primarily a function of light availability for phototrophic endoliths and grazers feeding upon them, is ~10 times stronger on the illuminated upside versus the shaded underside of substrates in the photic zone, with maximum rates in the intertidal (?631 g/m2/yr. Rates rapidly decline towards deeper waters where bioerosion and carbonate accretion are slow and epibenthic/endolithic communities take years to mature. Accretion rates are highest in the lower euphotic zone (955 g/m2/yr, where the substrate is less prone to hydrodynamic force. Highest rates are found – inversely to bioerosion – on downward facing substrates, suggesting that bioerosion may be a key factor governing the preferential settlement and growth of calcareous epilithobionts on downward facing substrates.

    In context of a latitudinal gradient, the Azores carbonate cycling rates plot between known values from the cold-temperate Swedish Kosterfjord and the tropical Bahamas, with a total range of two orders in magnitude. Carbonate budget calculations for the bathymetrical transect yield a mean 266.9 kg of epilithic carbonate production, ?54.6 kg of bioerosion, and 212.3 kg of annual net carbonate production per metre of coastline in the Azores C factory.

  1. Temperate carbonate cycling and water mass properties from intertidal to bathyal depths (Azores

    Directory of Open Access Journals (Sweden)

    M. Wisshak

    2010-08-01

    Full Text Available The rugged submarine topography of the Azores supports a diverse heterozoan association resulting in intense biotically-controlled carbonate-production and accumulation. In order to characterise this cold-water (C factory a 2-year experiment was carried out in the southern Faial Channel to study the biodiversity of hardground communities and for budgeting carbonate production and degradation along a bathymetrical transect from the intertidal to bathyal 500 m depth.

    Seasonal temperatures peak in September (above a thermocline and bottom in March (stratification diminishes with a decrease in amplitude and absolute values with depth, and tidal-driven short-term fluctuations. Measured seawater stable isotope ratios and levels of dissolved nutrients decrease with depth, as do the calcium carbonate saturation states. The photosynthetic active radiation shows a base of the euphotic zone in ~70 m and a dysphotic limit in ~150 m depth.

    Bioerosion, being primarily a function of light availability for phototrophic endoliths and grazers feeding upon them, is ~10 times stronger on the illuminated upside versus the shaded underside of substrates in the photic zone, with maximum rates in the intertidal (?631 g/m2/yr. Rates rapidly decline towards deeper waters where bioerosion and carbonate accretion are slow and epibenthic/endolithic communities take years to mature. Accretion rates are highest in the lower euphotic zone (955 g/m2/yr, where the substrate is less prone to hydrodynamic force. Highest rates are found – inversely to bioerosion – on down-facing substrates, suggesting that bioerosion may be a key factor governing the preferential settlement and growth of calcareous epilithobionts on down-facing substrates.

    In context of a latitudinal gradient, the Azores carbonate cycling rates plot between known values from the cold-temperate Swedish Kosterfjord and the tropical Bahamas, with a total range of two orders in magnitude. Carbonate budget calculations for the bathymetrical transect yield a mean 266.9 kg of epilithic carbonate production, ?54.6 kg of bioerosion, and 212.3 kg of annual net carbonate production per metre of coastline in the Azores C factory.

  2. Communicating Certainty About Nuclear Winter

    Science.gov (United States)

    Robock, A.

    2013-12-01

    I have been spending much of my time in the past several years trying to warn the world about the continuing danger of nuclear weapons, and that the solution is a rapid reduction in the nuclear arsenal. I feel that a scientist who discovers dangers to society has an ethical duty to issue a warning, even if the danger is so scary that it is hard for people to deal with. The debate about nuclear winter in the 1980s helped to end the nuclear arms race, but the planet still has enough nuclear weapons, even after reductions planned for 2017 under the New START treaty, to produce nuclear winter, with temperatures plunging below freezing in the summer in major agricultural regions, threatening the food supply for most of the planet. New research by myself, Brian Toon, Mike Mills, and colleagues over the past six years has found that a nuclear war between any two countries, such as India and Pakistan, using 50 atom bombs each of the size dropped on Hiroshima could produce climate change unprecedented in recorded human history, and a world food crisis because of the agricultural effects. This is much less than 1% of the current global arsenal. Communicating certainty - what we know for sure - has been much more effective than communicating uncertainty. The limited success I have had has come from persistence and serendipity. The first step was to do the science. We have published peer-reviewed articles in major journals, including Science, Nature, Proceedings of the National Academy of Sciences, Journal of Geophysical Research, Atmospheric Chemistry and Physics, Physics Today, and Climatic Change. But policymakers do not read these journals. Through fairly convoluted circumstances, which will be described in this talk, we were able to get papers published in Scientific American and the Bulletin of Atomic Scientists. I have also published several encyclopedia articles on the subject. As a Lead Author of Chapter 8 (Radiative Forcing) of the recently published Fifth Assessment Report of the Intergovernmental Panel on Climate Change (IPCC), I inserted a paragraph pointing out that volcanic eruptions serve as an analog that supports new work on nuclear winter. This is the first time that nuclear winter has been in the IPCC report. I will tell the story of the discussions within our chapter, with review editors, and with the IPCC leadership that resulted in a box in Chapter 8 that discusses nuclear winter. We gave a briefing to John Holdren, the President's Science Advisor, about the work. Daniel Ellsberg, Fidel Castro, and Mikhail Gorbachev found out about our work, and used the results to appeal for nuclear abolition. In 2013 the work was featured at the Conference on the Humanitarian Impact of Nuclear Weapons in Oslo, Norway attended by 132 nations, and I gave a TEDx talk, I published an opinion piece on the CNN website, and I gave an invited public lecture in Nagasaki, Japan, all about the climatic consequences of nuclear war. I am now using Twitter and Facebook to communicate about nuclear winter. The threat that nuclear weapons pose to the planet is a much easier problem to solve than global warming. We need to eliminate nuclear weapons so we have the luxury of working on the global warming problem without the possibility of the existential global threat still posed by the global nuclear arsenal.

  3. Atom Probe Tomography Analysis of Precipitation during Tempering of a Nanostructured Bainitic Steel

    Energy Technology Data Exchange (ETDEWEB)

    Caballero, Francesca G. [CENIM-CSIC, Madrid, Spain; Miller, Michael K [ORNL; Garcia-Mateo, C. [CENIM-CSIC, Madrid, Spain

    2011-01-01

    Carbon distribution during tempering of a nanostructured bainitic steel was analyzed by atom probe tomography (APT). Three different types of particles are detected on samples tempered at 673 K (400 C) for 30 minutes: lower bainite cementite with a carbon content of {approx}25 at. pct, {var_epsilon}-carbides with a carbon content close to 30 at. pct, and carbon clusters, small features with a carbon content of {approx}14 at. pct indicative of a stage of tempering prior to precipitation of {var_epsilon}-carbide. After tempering at 773 K (500 C) for 30 minutes, the {var_epsilon}-carbide-to-cementite transition was observed. Solute concentration profiles across carbide/ferrite interfaces showed the distribution of substitutional elements in {var_epsilon}-carbide and cementite for all the tempering conditions.

  4. Effect of tempering on microstructure and mechanical properties of a non-quenched bainitic steel

    International Nuclear Information System (INIS)

    The effect of tempering on the microstructure and mechanical properties of a non-quenched (NQ) bainitic steel was investigated by optical microscopy, X-ray diffractometry, scanning electronic microscope (SEM) and transmission electronic microscopy (TEM). The results show that the NQ steel which has been investigated is granular bainite composed of bainitic ferrite lath, retained austenite film and island of austenite and martensite (M/A island) before tempering. The amount of retained austenite decreases with the rise of tempering, slowly before 400 deg. C, sharply at 450 deg. C, and it is close to 0 at 600 deg. C. When tempered at 350 deg. C, this kind of NQ steel has the optimum mechanical properties because of M/A islands partly decomposition, especially for the martensite in the M/A islands. However, when tempered at 450 deg. C, it appears brittleness, which results from carbides distributing along prior austenite grains because M/A island is largely decomposed.

  5. Quantitative consideration for the tempering effect during multi-pass thermal cycle in HAZ of low-alloy steel

    International Nuclear Information System (INIS)

    A new Thermal Cycle Tempering Parameter (TCTP) to deal with the tempering effect during multi-pass thermal cycles has been proposed by extending Larson-Miller parameter (LMP). Experimental result revealed that the hardness in synthetic HAZ of the low alloy steel subjected to multi tempering thermal cycles has a good linear relationship with TCTP. By using this relationship, the hardness of the low-alloy steel reheated with tempering thermal cycles can be predicted when the original hardness is known. (author)

  6. Doughnut In The Desert: Vertical Structure Of A Winter Production Pulse

    Science.gov (United States)

    Green, S. A.; Budd, J. W.; Kerfoot, W. C.

    2005-12-01

    SeaWiFS imagery has revealed a spatially complex, annually reoccurring pattern of chl a in the open waters of Southern Lake Michigan during late winter to early spring (March-April). The circular ring (doughnut) persists for weeks and occurs every year. A cross-lake survey in April 2001 confirmed the doughnut pattern and demonstrated that the gyre structure penetrated throughout the well-mixed water column. Spatial images suggest the feature may be related to the transport of phosphorus-rich coastal sediments which are entrained along gyre convergence zones and moved into the southern central region, enhancing deep-water production. Vertical reconstructions from two separate profiling instruments (CTD vertical casts, horizontal tows with an optical plankton counter) uncovered columnar patterns of Chl a, temperature, and other variables consistent with a spatially complex, rotating gyre structure. The horizontal surface patterns and vertical profiles suggest a heretofore unrecognized coupling between winter gyre formation, sediment resuspension, and deep-water productivity. The Chl a pattern is superimposed upon a spatially heterogeneous late-winter phytoplankton and zooplankton distribution pattern. The winter productivity pulse marked by the doughnut may explain how certain zooplankton species characteristic of the Great Lakes fauna can successfully over-winter through what was previously perceived as a very unproductive and resource-stressful period.

  7. Temper Outbursts in Paediatric Obsessive-Compulsive Disorder and Their Association with Depressed Mood and Treatment Outcome

    Science.gov (United States)

    Krebs, Georgina; Bolhuis, Koen; Heyman, Isobel; Mataix-Cols, David; Turner, Cynthia; Stringaris, Argyris

    2013-01-01

    Background: Temper outbursts in youth with obsessive-compulsive disorder (OCD) are a common source of concern, but remain poorly understood. This study examined a set of hypotheses related to: (a) the prevalence of temper outbursts in paediatric OCD, (b) the associations of temper outbursts with OCD severity and depressive symptoms; and (c) the…

  8. Benthic fluxes of dissolved organic carbon in three temperate Australian estuaries: Implications for global estimates of benthic DOC fluxes

    Science.gov (United States)

    Maher, D. T.; Eyre, B. D.

    2010-12-01

    Light and dark benthic dissolved organic carbon (DOC) fluxes and sediment characteristics (total organic carbon (TOC), total nitrogen (TN), TOC isotope ratio (?13C), phospholipid fatty acid (PLFA) concentration, and compound-specific ?13C) were measured seasonally in a range of habitats in three warm-temperate Australian estuaries to determine what factors control benthic DOC fluxes. Benthic DOC fluxes were seasonal with the highest rates generally observed during summer. Most habitats displayed uptake of DOC during the dark and efflux during the light, and were a net source of DOC to the overlying waters over the diel cycle. Macrophyte habitats (seagrass and macroalgae) had the highest benthic fluxes of DOC (up to ˜50 mmol C m-2 d-1). Organic matter supply to the sediment was dominated by in situ production, and both quantity and source exerted control over benthic DOC fluxes. DOC flux was tightly coupled to bacteria and algal PLFA concentrations during summer, and algal PLFA concentrations during winter, indicating a strong influence of microbial interactions on benthic DOC flux and a temperature-related decoupling of algae and bacteria under cooler conditions. Estimates of the global estuarine benthic DOC flux indicate that these areas are a significant source of DOC to the ocean (1-41 Tg C yr -1). Inclusion of macrophyte, salt marsh, mangrove, and intertidal benthic DOC flux estimates resulted in a higher global continental margin benthic DOC flux (106-416 Tg C yr -1) than the previous estimate (90 Tg C yr-1).

  9. Generalized Fibonacci zone plates

    CERN Document Server

    Ke, Jie; Zhu, Jianqiang

    2015-01-01

    We propose a family of zone plates which are produced by the generalized Fibonacci sequences and their axial focusing properties are analyzed in detail. Compared with traditional Fresnel zone plates, the generalized Fibonacci zone plates present two axial foci with equal intensity. Besides, we propose an approach to adjust the axial locations of the two foci by means of different optical path difference, and further give the deterministic ratio of the two focal distances which attributes to their own generalized Fibonacci sequences. The generalized Fibonacci zone plates may allow for new applications in micro and nanophotonics.

  10. On Brillouin Zones

    OpenAIRE

    Veerman, J. J. P.; Peixoto, M. M.; Rocha, A. C.; Sutherland, S.

    1998-01-01

    Brillouin zones were introduced by Brillouin in the thirties to describe quantum mechanical properties of crystals, that is, in a lattice in $\\R^n$. They play an important role in solid-state physics. It was shown by Bieberbach that Brillouin zones tile the underlying space and that each zone has the same area. We generalize the notion of Brillouin Zones to apply to an arbitrary discrete set in a proper metric space, and show that analogs of Bieberbach's results hold in this...

  11. Immune zones in leprosy

    Directory of Open Access Journals (Sweden)

    Rajashekar T

    2009-01-01

    Full Text Available Leprosy affects mainly those areas of skin which have a relatively lower temperature and are more exposed to trauma. Certain zones like scalp, palms and soles, genitalia, groins, axillae, eyelids, transverse band of skin over lumboscaral area, midline of back and perineum have been described to be immune to the development of lesions in leprosy. But clinical, histological and bacteriological evidence of involvement of these so called immune zones though infrequent have been documented. Hence, these immune zones should be termed as relatively immune, rather than absolutely immune zones of leprosy.

  12. Why bacteria are smaller in the epilimnion than in the hypolimnion? A hypothesis comparing temperate and tropical lakes

    Directory of Open Access Journals (Sweden)

    Roberto Bertoni

    2012-01-01

    Full Text Available Bacterial size and morphology are controlled by several factors including predation, viral lysis, UV radiation, and inorganic nutrients. We observed that bacterial biovolume from the hypolimnion of two oligotrophic lakes is larger than that of bacteria living in the layer from surface to 20 m, roughly corresponding to the euphotic/epilimnetic zone. One lake is located in the temperate region at low altitude (Lake Maggiore, Northern Italy and the other in the tropical region at high altitude (Lake Alchichica, Mexico. The two lakes differ in oxygen, phosphorus and nitrogen concentrations and in the temperature of water column. If we consider the two lakes separately, we risk reducing the explanation of bacterial size variation in the water column to merely regional factors. Comparing the two lakes, can we gather a more general explanation for bacterial biovolume variation. The results showed that small bacteria dominate in the oxygenated, P-limited epilimnetic waters of both lakes, whereas larger cells are more typical of hypolimnetic waters where phosphorus and nitrogen are not limiting. Indeed, temperature per se cannot be invoked as an important factor explaining the different bacterial size in the two zones. Without excluding the top-down control mechanism of bacterial size, our data suggest that the average lower size of bacterial cells in the epilimnion of oligotrophic lakes is controlled by outcompetition over the larger cells at limiting nutrients.

  13. Terrestrial and stream chemical linkages reveal extent of rock weathering in the perhumid coastal temperate rainforest of Alaska.

    Science.gov (United States)

    D'Amore, D. V.; Trainor, T.

    2014-12-01

    Climate influences the rate of reactions that drive material fluxes, especially the rock-water interaction within the earth's critical zone. The perhumid temperate rainforests of southeast Alaska (PCTR) are valuable sites for testing theories and applying models for ecosystem development. The landscape of the PCTR is chronologically young, but by contrast, has experienced rapid change during the Holocene due to a humid climate that promotes intense soil weathering and rapid accumulation of soil organic carbon. We investigated the magnitude of present rock-water interaction in several catchments and watersheds arrayed across a spectrum of this landscape evolution. All of the catchments had evidence of weathering as indicated by cation export relative to sea-salt aerosol input. The magnitude of the weathering signature was inversely related to the accumulation of organic carbon in the catchment. We conclude that biological processes inhibit the weathering of lithologic materials due to organic matter accumulation. However, there is clear evidence that the landscape is still actively weathering. The extent of the consumption of CO2 by rock weathering will be critical in determining long-term carbon budgets in the region and determining the sink strength of the terrestrial ecosystem. This study provides a template for examining landscape evolution in the context of critical zone science in a relatively pristine landscape.

  14. Quantifying the risks of winter damage on overwintering crops under future climates: Will low-temperature damage be more likely in warmer climates?

    Science.gov (United States)

    Vico, G.; Weih, M.

    2014-12-01

    Autumn-sown crops act as winter cover crop, reducing soil erosion and nutrient leaching, while potentially providing higher yields than spring varieties in many environments. Nevertheless, overwintering crops are exposed for longer periods to the vagaries of weather conditions. Adverse winter conditions, in particular, may negatively affect the final yield, by reducing crop survival or its vigor. The net effect of the projected shifts in climate is unclear. On the one hand, warmer temperatures may reduce the frequency of low temperatures, thereby reducing damage risk. On the other hand, warmer temperatures, by reducing plant acclimation level and the amount and duration of snow cover, may increase the likelihood of damage. Thus, warmer climates may paradoxically result in more extensive low temperature damage and reduced viability for overwintering plants. The net effect of a shift in climate is explored by means of a parsimonious probabilistic model, based on a coupled description of air temperature, snow cover, and crop tolerable temperature. Exploiting an extensive dataset of winter wheat responses to low temperature exposure, the risk of winter damage occurrence is quantified under conditions typical of northern temperate latitudes. The full spectrum of variations expected with climate change is explored, quantifying the joint effects of alterations in temperature averages and their variability as well as shifts in precipitation. The key features affecting winter wheat vulnerability to low temperature damage under future climates are singled out.

  15. A SIMPLE WINTER PROTECTION SYSTEM FOR BLACKBERRIES

    Science.gov (United States)

    Little commercial blackberry production exists in areas with severe winters (minimum winter temperatures below -12 degrees C and short growing seasons. In this study, we evaluated the combination of simple cultural practices, a modified rotatable cross-arm (RCA) trellis system, and covering plants w...

  16. Does cold winter weather produce depressive symptoms?

    Science.gov (United States)

    Garvey, Michael J.; Goodes, Mike; Furlong, Candy; Tollefson, Gary D.

    1988-06-01

    To examine whether harsh winter weather is associated with depressive symptoms, 45 healthy subjects from Minnesota were compared to 42 subjects from California near the end of the winter season. No differences in the prevalence of depressive symptoms were found between the two groups.

  17. Efeito do revenido na resistência à corrosão dos aços inoxidáveis supermartensíticos / Effect of tempering on the corrosion resistance of supermartensitic stainless steels

    Scientific Electronic Library Online (English)

    Ana Paula Ciscato, Camillo; Carlos Alberto Della, Rovere; José Mario de, Aquino; Sebastião Elias, Kuri.

    2010-03-01

    Full Text Available Os aços inoxidáveis supermartensíticos são utilizados nas indústrias de petróleo e gás, pois aliam boas propriedades mecânicas, soldabilidade e excelente resistência à corrosão. Eles são endurecidos pelo tratamento térmico de têmpera e, para otimizar suas propriedades mecânicas, são submetidos ao re [...] venimento. Durante o revenimento, ocorre precipitação de fases, que, dependendo dos parâmetros temperatura e tempo, induz alterações indesejadas nas propriedades desses aços. Nesse trabalho, o objetivo foi estudar a microestrutura e a resistência à corrosão de um aço inoxidável supermartensítico em diferentes condições de revenido (550°C, 600°C e 650°C). Observou-se, na microestrutura da amostra revenida a 650°C, a formação de austenita e precipitados de cromo do tipo Cr3C2 e Cr7C3. As curvas de polarização indicaram que o tratamento térmico influencia o comportamento anódico, modificando a região passiva e as características do filme passivo. O revenido altera a resistência à corrosão, com o grau de sensitização diminuindo com o aumento de temperatura de 550°C para 650°C, devido à recuperação das zonas empobrecidas de cromo. Abstract in english Supermartensitic stainless steels have been used in the oil and gas industry for onshore and offshore tubing applications, due to their good mechanical properties, weldability and excellent corrosion resistance. They are hardened by quenching heat treatment, and to improve their toughness, are submi [...] tted to tempering. During the tempering, some phase precipitation occurs, which depending on the time and temperature parameters, produces some undesired changes in the steel properties. The aim of this research was to study the microstructure and the corrosion resistance of supermartensitic stainless steel in quenched and different tempered conditions (550°C, 600°C and 650°C). At the microstructure of the 650°C tempered sample was observed the formation of austenite and precipitates of chromium, like Cr3C2 and Cr7C3.The polarization curves indicated that the heat treatment influences the anodic behavior, changing the passive region and the passive film characteristics. The tempering changes the corrosion resistance, decreasing the degree of sensitization when increasing the temperature from 550°C to 650°C, this occurs due to the recovery of the chromium impoverished zones.

  18. Enhanced Monte Carlo Sampling through Replica Exchange with Solute Tempering

    Science.gov (United States)

    2015-01-01

    With a view to improving the consistency of free energy perturbation calculations in Monte Carlo simulations of protein–ligand complexes, we have implemented the replica exchange with solute tempering (REST) method in the MCPRO software. By augmenting the standard REST approach with regular attempted jumps in selected dihedral angles, our combined method facilitates sampling of ligand binding modes that are separated by high free energy barriers and ensures that computed free energy changes are considerably less dependent on the starting conditions and the chosen mutation pathway than those calculated with standard Monte Carlo sampling. We have applied the enhanced sampling method to the calculation of the activities of seven non-nucleoside inhibitors of HIV-1 reverse transcriptase, and its Tyr181Cys variant, and have shown that a range of binding orientations is possible depending on the nature of the ligand and the presence of mutations at the binding site. PMID:24803853

  19. The Fracture Process of Tempered Soda-Lime-Silica Glass

    DEFF Research Database (Denmark)

    Nielsen, Jens Henrik; Olesen, John Forbes

    2009-01-01

    This work presents experimental observations of the characteristic fracture process of tempered glass. Square specimens with a side length of 300 mm, various thicknesses and a residual stress state characterized by photoelastic measurements were used. Fracture was initiated using a 2.5 mm diamond drill and the fragmentation process was captured using High-Speed digital cameras. From the images, the average speed of the fracture front propagation was determined within an accuracy of 1.0%. Two characteristic fragments were found to form on each side of the initiation point and are named “Whirl-fragments” referring to the way they are generated. An earlier estimation of the in-plane shape of the fracture front is corrected and a hypothesis on the development for the fracture front is offered. The hypothesis is supported by investigations of the fragments using a Scanning Electron Microscope (SEM) which also revealed a micro scale crack bridging effect.

  20. Temperance, alcohol, and the American evangelical: a reassessment.

    Science.gov (United States)

    Warner, Jessica

    2009-07-01

    Abstinence from alcohol is a way of life for many American evangelicals, with rates of abstention running at over 70% among some Pentecostal denominations. This paper examines the religious beliefs that, historically, have supported teetotalism. The most notable of these is Christian perfection, a doctrine that originated in 18th-century England, that was then radicalized in America in the early 19th century. Abstinence from alcohol is highest among denominations that make Christian perfection the cornerstone of their teachings, and lowest among those that discount human agency. The paper also argues that 19th-century American evangelicals were by no means committed uniformly to temperance as a way of life, and that this was especially true of the various Methodist churches. PMID:19563558

  1. On fractional tempered stable processes and their governing differential equations

    Science.gov (United States)

    Beghin, Luisa

    2015-07-01

    We derive the governing equation of the Tempered Stable Subordinator (hereafter TSS), which generalizes the space-fractional differential equation satisfied by the law of the ?-stable subordinator itself. This equation is expressed in terms of the shifted fractional derivative of order ? ? (0 , 1) coinciding with the stability parameter. We then generalize this equation by introducing a time-fractional derivative of order ? ? (0 , 1) (resp. 1 / ? > 1) and we prove that it is satisfied by the law of a TSS time-changed by the inverse of a ?-stable subordinator (resp. by the stable subordinator itself). The corresponding processes can therefore be called "fractional TS processes". Finally we provide fractional extensions of the relativistic stable processes, which we define as a Brownian motion with a random time argument represented by independent fractional TS processes of order ? (resp. 1 / ?).

  2. Adaptive Parallel Tempering for Stochastic Maximum Likelihood Learning of RBMs

    CERN Document Server

    Desjardins, Guillaume; Bengio, Yoshua

    2010-01-01

    Restricted Boltzmann Machines (RBM) have attracted a lot of attention of late, as one the principle building blocks of deep networks. Training RBMs remains problematic however, because of the intractibility of their partition function. The maximum likelihood gradient requires a very robust sampler which can accurately sample from the model despite the loss of ergodicity often incurred during learning. While using Parallel Tempering in the negative phase of Stochastic Maximum Likelihood (SML-PT) helps address the issue, it imposes a trade-off between computational complexity and high ergodicity, and requires careful hand-tuning of the temperatures. In this paper, we show that this trade-off is unnecessary. The choice of optimal temperatures can be automated by minimizing average return time (a concept first proposed by [Katzgraber et al., 2006]) while chains can be spawned dynamically, as needed, thus minimizing the computational overhead. We show on a synthetic dataset, that this results in better likelihood ...

  3. Temperance internationalism: Guy Hayler and the World Prohibition Federation.

    Science.gov (United States)

    Fahey, David M

    2006-01-01

    The World Prohibition Federation, organized in 1909, and the International Record, published from 1917 to 1968, sought to internationalize the temperance movement by collecting and disseminating anti-drink news from around the globe. The Federation was based in London, and most of its activities were English-speakers. A British reformer named Guy Hayler served as its honorary president for thirty years and edited the "International Record" until his death in 1943. The Federation emphasized that prohibitionists comprised a moral community, united regardless of race, religion, nationality, or politics. Poorly funded, the Federation had difficulty competing with the World League against Alcoholism after the Anti-Saloon League of America organized this rival propaganda society in 1919. PMID:20063495

  4. The testicular cycle of captive Tupinambis merianae lizards in a temperate environment

    Directory of Open Access Journals (Sweden)

    Noriega, Teresa

    2002-08-01

    Full Text Available Las poblaciones de Tupinambis merianae, que habitan las regiones templadas y subtropicales, muestran un comportamiento marcadamente estacional con períodos equivalentes de actividad e hibernación. Correspondientemente, la reproducción en estos lagartos es un fenómeno cíclico caracterizado por una corta actividad sexual primaveral. Este trabajo examina los cambios testiculares que ocurren durante el ciclo reproductivo de especímenes de Tupinambis merianae criados en un ambiente templado. Evalúa la participación de la porción renal sexual como glándula sexual secundaria. En otoño e invierno, el testículo exhibe una gametogénesis discontinua. La espermatocitogénesis ocurre en otoño dando lugar a una espermiogénesis precoz abortiva, que concluye en los meses fríos. En la primavera temprana, la gónada reinicia su actividad espermiogénica alcanzando prontamente un pico de máximo crecimiento y abundante producción de esperma. El clímax testicular ocurre brevemente después de la hibernación y coincide con un período de cópulas de alrededor de un mes (octubre. En ese período, el epidídimo considerablemente dilatado se encuentra revestido por un epitelio cilíndrico y contiene grandes masas de esperma. Simultáneamente, la porción sexual de los túbulos renales exhibe células columnares hipertróficas cargadas de grandes gránulos citoplasmáticos PAS (+. Pronto la actividad reproductiva cesa y da lugar a una fase de involución gonadal, que se extiende a través del resto de la primavera y verano (noviembre-febrero, indicando la existencia de un único evento reproductivo al ario. Las observaciones se discuten en relación con los factores climáticos y las características biológicas del grupo. Tupinambis merianae populations living in temperate and subtropical regions show a distinctly seasonal behaviour, with equivalent periods of activity and hibernation. Correspondingly, reproduction in these lizards is a cyclic phenomenon, characterized by a short spring sexual activity. This work examines the testicular changes that occur during the reproductive cycle of Tupinambis merianae specimens raised in a temperate environment. The involvement of the kidney sexual portion as a secondary sexual gland is also considered. In autumn and winter, the testicle exhibits a discontinuous gametogenesis. Spermacytogenesis takes place in autumn, giving rise to a precocious abortive spermiogenesis which concludes at cool months. At early spring, the gonad restarts its spermiogenetic activity attaining promptly a peak of maximal growth and abundant sperm production. The testicular climax occurs shortly after hibernation and coincides with a mating period of about a month (October. At that period, the quite enlarged epididymis is lined with a cylindrical epithelium and contains large sperm masses. Simultaneously, the sexual portions of kidney tubules display hypertrophic columnar cells filled with large PAS (+ cytoplasmic granules. Soon, the reproductive activity ceases and makes way for a phase of gonadal involution which extends through the rest of spring and summer (November-February, indicating the existence of a single reproductive event per year. The observations are discussed in connection with climate factors and biological features of the group.

  5. Social implications of residential demand response in cool temperate climates

    International Nuclear Information System (INIS)

    Residential electrical demand response (DR) offers the prospect of reducing the environmental impact of electricity use, and also the supply costs. However, the relatively small loads and numerous actors imply a large effort: response ratio. Residential DR may be an essential part of future smart grids, but how viable is it in the short to medium term? This paper reviews some DR concepts, then evaluates the propositions that households in cool temperate climates will be in a position to contribute to grid flexibility within the next decade, and that that they will allow some automated load control. Examples of demand response from around the world are discussed in order to assess the main considerations for cool climates. Different tariff types and forms of control are assessed in terms of what is being asked of electricity users, with a focus on real-time pricing and direct load control in energy systems with increasingly distributed resources. The literature points to the significance of thermal loads, supply mix, demand-side infrastructure, market regulation, and the framing of risks and opportunities associated with DR. In concentrating on social aspects of residential demand response, the paper complements the body of work on technical and economic potential. - Highlights: ? Demand response implies major change in governance of electricity systems. ? Households in cool temperate climates can be flexible, mainly with thermal loads. ? DR requires simple tarifal loads. ? DR requires simple tariffs, appropriate enabling technology, education, and feedback. ? Need to test consumer acceptance of DR in specific conditions. ? Introduce tariffs with technologies e.g., TOU tariff plus DLC with electric vehicles.

  6. Evolution of temperate pathogens: the bacteriophage/bacteria paradigm

    Directory of Open Access Journals (Sweden)

    Koch Arthur L

    2007-11-01

    Full Text Available Abstract Background Taking as a pattern, the T4 and lambda viruses interacting with each other and with their Gram-negative host, Escherichia coli, a general model is constructed for the evolution of 'gentle' or temperate pathogens. This model is not simply either pure group or kin selection, but probably is common in a variety of host-parasite pairs in various taxonomic groups. The proposed mechanism is that for its own benefit the pathogen evolved ways to protect its host from attack by other pathogens and this has incidentally protected the host. Although appropriate mechanisms would have been developed and excluded related viral species and also other quite different pathogens, the important advance would have been when other individuals of the same species that arrive at the host subsequent to the first infecting one were excluded. Results Such a class of mechanisms would not compete one genotype with another, but simply would be of benefit to the first pathogen that had attacked a host organism. Conclusion This would tend to protect and extend the life of the host against the detrimental effects of a secondarily infecting pathogen. This leads to the pathogens becoming more temperate via the now favorable co-evolution with its host, which basically protects both host and virus against other pathogens but may cause slowing of the growth of the primary infecting pathogen. Evolution by a 'gentle' strategy would be favored as long as the increased wellbeing of the host also favored the eventual transmission of the early infecting pathogen to other hosts.

  7. Investigating Aquatic Dead Zones

    Science.gov (United States)

    Testa, Jeremy; Gurbisz, Cassie; Murray, Laura; Gray, William; Bosch, Jennifer; Burrell, Chris; Kemp, Michael

    2010-01-01

    This article features two engaging high school activities that include current scientific information, data, and authentic case studies. The activities address the physical, biological, and chemical processes that are associated with oxygen-depleted areas, or "dead zones," in aquatic systems. Students can explore these dead zones through both…

  8. Effect of groove design on mechanical and metallurgical properties of quenched and tempered low alloy abrasion resistant steel welded joints

    International Nuclear Information System (INIS)

    Highlights: • Effect of weld groove design on Q and T steel welded joints is investigated. • Groove design influences heat dissipation characteristics of welded joints. • Double-V groove joint possesses maximum yield strength and UTS. • C-groove joint possesses highest impact energy, both at room temperature and 0 °C. • A wide variation in microhardness exists across different zone of the weldments. - Abstract: Experimental investigations were carried out to study the influence of three different groove designs on mechanical and metallurgical properties of 15 mm thick Q and T (quenched and tempered) steel welded joints. Welding heat input variation corresponding to each joint configuration was kept to a minimal such that the objective of investigating, exclusively, the effect of varied weld volume on the mechanical and metallurgical performance of these joints could be accomplished. Mechanical performance of these joints was evaluated by subjecting them to transverse tensile testing, and Charpy V-notch impact testing of the weld zones at room temperature and 0 °C. The results of this study reveal that among all types of groove formations used for welding, double-V groove joint possessed maximum YS (yield strength) and UTS (ultimate tensile strength), besides maximum strength ratio (YS/UTS) that was followed by U-groove joint and C-groove joint, respectively. However, weld zone tested individually, for the cover as well as the root pass of the C-groove joint possessed highest CVN (Charpy V-notch) values, both at room temperature and 0 °C. Extensive microhardness studies of these weldments showed a wide variation in the microhardness values of the weld zone and the HAZ (heat affected zone). It was concluded that each groove formation/design exerted a significant influence on the heat dissipation characteristics of these joints, which is evident from different morphological features as revealed through optical microscopy. Scanning electron microscopic studies on tensile and impact tested specimens indicate that despite of achieving undermatched welds that were accompanied with a high degree of metallurgical heterogeneity, the mode of failure in the weld zone was largely ductile

  9. DETERMINATION OF THE OPTIMAL TEMPERING TEMPERATURE IN HARD FACING OF THE FORGING DIES

    Directory of Open Access Journals (Sweden)

    Milan Mutavdži?

    2012-06-01

    Full Text Available Here is analyzed selection of the optimal technology for heat treatment during the reparation of the damaged forging dies. Those tools are manufactured from alloyed tool steels for operation at elevated temperatures. Those steels are prone to self-hardening, so in reparatory hard-facing they must be preheated, additionally heated and tempered. During the tempering, in temperature interval 500-600°C, a secondary increase of hardness and decrease of impact toughness occurs, the so-called reversible tempering brittleness. Here is shown that it can be avoided by application of metallurgical and technological measures. Metallurgical measures assume adequate selection of steels. Since the considered steels are per se prone to tempering brittleness, we conducted experimental investigations to define the technological measures to avoid it. Tests on models were conducted: tempering from different temperatures, slow heating and cooling in still air. Hardness measurements showed that at 520°C, the secondary increase of hardness occurs, with drop of the impact toughness. Additional hard-facing tests included samples tempered at various regimes. Samples were prepared for mechanical and metallographic investigations. Results presented illustrate influence of additional heat treatment on structure, hardness and mechanical properties of the hard-faced layers. This enabled establishing the possibility of avoiding the tempering brittleness through technological measures.

  10. Determination of the optimal tempering temperature in hard facing of the forging dies

    Directory of Open Access Journals (Sweden)

    Milan Mutavdži?

    2012-05-01

    Full Text Available Here is analyzed selection of the optimal technology for heat treatment during the reparation of the damaged forging dies. Those tools are manufactured from alloyed tool steels for operation at elevated temperatures. Those steels are prone to self-hardening, so in reparatory hard-facing they must be preheated, additionally heated and tempered. During the tempering, in temperature interval 500-600°C, a secondary increase of hardness and decrease of impact toughness occurs, the so-called reversible tempering brittleness. Here is shown that it can be avoided by application of metallurgical and technological measures. Metallurgical measures assume adequate selection of steels. Since the considered steels are per se prone to tempering brittleness, we conducted experimental investigations to define the technological measures to avoid it. Tests on models were conducted: tempering from different temperatures, slow heating and cooling in still air. Hardness measurements showed that at 520°C, the secondary increase of hardness occurs, with drop of the impact toughness. Additional hard-facing tests included samples tempered at various regimes. Samples were prepared for mechanical and metallographic investigations. Results presented illustrate influence of additional heat treatment on structure, hardness and mechanical properties of the hard-faced layers. This enabled establishing the possibility of avoiding the tempering brittleness through technological measures. 

  11. Impact of inter-annual climatic variability on ecosystem carbon exchange in two grazed temperate grasslands with contrasting drainage regimes

    Science.gov (United States)

    Choncubhair, Órlaith Ní; Humphreys, James; Lanigan, Gary

    2014-05-01

    Temperate grasslands constitute over 30% of the Earth's naturally-occurring biomes and make an important contribution towards the partial mitigation of anthropogenic greenhouse gas emissions by terrestrial ecosystems. Accumulation of carbon (C) in grassland systems predominantly takes place in below-ground repositories, enhanced by the presence of a stable soil environment with low carbon turnover rates, active rhizodeposition and high levels of residue and organic inputs. Predicted future warming is expected to increase productivity in temperate zones, thereby enhancing rates of terrestrial carbon sequestration. However, the susceptibility of many ecosystems, including grasslands, to extreme climatic events and inter-annual variability has been demonstrated previously. Temperature anomalies as well as modifications in the temporal pattern and quantity of precipitation alter the balance between carbon uptake and release processes and a mechanistic understanding of ecosystem response to such changes is still lacking. In the present study, the impact of extreme inter-annual variability in summer rainfall and temperature on carbon dynamics in two rotationally-grazed grasslands in Ireland was examined. The sites experience similar temperate climatic regimes but differ in soil drainage characteristics. Eddy covariance measurements of net ecosystem exchange of carbon were complemented by regular assessment of standing biomass, leaf cover, harvest exports and organic amendment inputs. The summers of 2012 and 2013 showed contrasting climatic conditions, with summer precipitation 93% higher and 25% lower respectively than long-term means. In addition, soil temperatures were 7% lower and 11% higher than expected. Cool, wet conditions in 2012 facilitated net carbon uptake for more than ten months of the year at the poorly-drained site, however the ecosystem switched to a net source of carbon in 2013 during months with significantly reduced rainfall. In contrast, net C accumulation continued at the well-drained site despite the summer drought conditions. Total cumulative annual ecosystem respiration was 20% higher at the poorly-drained site than at the well-drained site in 2013, while a more modest increase in cumulative gross production (9.6%) was observed at the poorly-drained site for the same period. This research highlights the susceptibility of poorly-drained soils to accelerated efflux of carbon during soil drying cycles and points towards potential negative impacts of future warming scenarios, with significant carbon balance implications for grassland ecosystems.

  12. Longitudinal zonation of macroinvertebrates in an Ecuadorian glacier-fed stream: do tropical glacial systems fit the temperate model?

    DEFF Research Database (Denmark)

    Jacobsen, D.; Dangles, O.

    2010-01-01

    P>1. The ecology of glacier-fed streams at temperate latitudes has been intensely studied in recent years, leading to the development of a well-validated conceptual model on the longitudinal distribution of macroinvertebrate communities downstream of the glacier margin (Freshwater Biology, 2001a; 46, 1833). However, to our knowledge, the ecology of tropical glacier-fed streams has not yet been studied. 2. We sampled benthic macroinvertebrates and measured environmental variables at nine sites between 4730 and 4225 m altitude along a 4.3 km stretch of a glacier-fed stream 40 km south of the equator in the Ecuadorian Andes. Our goal was to study the longitudinal distribution of the fauna in relation to environmental factors and to compare this with the conceptual model based on temperate-arctic glacier-fed streams. 3. Total density of invertebrates differed considerably at the two highest altitude sites; 4600 m-2 at a pro-glacial lake outlet and only 4 m-2 at a site originating directly from the glacier snout. Otherwise, there was a downstream decrease in density to about 825 m-2 at the three lowest sites. Taxon richness increased with distance from the glacier, very similar to the pattern predicted. A total of 28 taxa were collected; two at the glacier snout, seven at the nearby pro-glacial lake outlet, 13 at site 2 (<400 m from the glacier) and 20 at the lowest sites. 4. The numerical percentage of Chironomidae (Diptera) decreased downstream from 100 to 44%. The subfamily Podonominae was numerous at the highest sites but became much less important further downstream. The Orthocladiinae were important both in numbers and species at all sites, while Diamesinae were numerous only in the middle of the reach studied and were completely absent from the upper three sites. The limited importance of the Diamesinae, and its replacement by Podonominae, is different from the pattern typically observed in north-temperate glacier-fed streams. This could be because of the fact that the genus Diamesa is missing from the Neotropics. 5. Stream temperature and channel stability explained most of the variability in faunal composition and richness, supporting the model. Stability increased systematically downstream while temperature did not. Surprisingly, no classical kryal zone (T-max <4 degrees C) was found, as even the site closest to the glacier snout (50 m) had a T-max of 15 degrees C and no site had T-max <8 degrees C. We propose that this might be a general feature of equatorial glacial streams

  13. Relationships among soil properties, plant nutrition and arbuscular mycorrhizal fungi-plant symbioses in a temperate grassland along hydrologic, saline and sodic gradients.

    Science.gov (United States)

    García, Ileana V; Mendoza, Rodolfo E

    2008-03-01

    Temporal variations in the relationships among plant nutrient concentrations, soil properties and arbuscular-mycorrhizal (AM) fungal dynamics were studied along a topographic and saline gradient in a temperate grassland soil. Soil and plant (Lotus tenuis, Paspalum vaginatum, Stenotaphrum secundatum) samples were collected on four seasonally based occasions. The morphology of AM root colonization had a similar pattern in the plants studied. Maximum arbuscular colonization occurred at the beginning of the growing season in late winter and was minimal in late summer, but maximal vesicular colonization occurred in summer and was minimal in winter, suggesting a preferential production of these morphological phases by the fungus with respect to season. The greatest arbuscular colonization was associated with the highest N and P concentrations in plant tissue, suggesting a correspondence with increases in the rate of nutrient transfer between the symbiotic partners. Water content, salinity and sodicity in soil were positively associated with AM root colonization and arbuscule colonization in L. tenuis, but negatively so in the grasses. There were distinct seasonally related effects with respect to both spore density and AM colonization, which were independent of particular combinations of plant species and soil sites. PMID:18205811

  14. Loricate Choanoflagellates from the South Atlantic coastal zone (~32 °S) including the description of Diplotheca tricyclica sp. nov. / Choanoflagelados Loricados da zona costeira do Atlântico Sul (~32 ºS) incluindo a descrição de Diplotheca tricyclica sp. nov.

    Scientific Electronic Library Online (English)

    Marli, Bergesch; Clarisse, Odebrecht; Øjvind, Moestrup.

    2008-12-01

    Full Text Available A biodiversidade de protistas heterotróficos é pouco conhecida na zona costeira do Atlântico Sul (~32 °S), especialmente dos nanoflagelados. No presente estudo, foi registrada pela primeira vez a presença de coanoflagelados loricados no estuário da Lagoa dos Patos e na zona costeira adjacente. Dezes [...] sete espécies de onze gêneros de coanoflagelados loricados foram observadas em amostras de água fixadas (solução de lugol + glutaraldeido) coletadas entre outubro de 1998 e maio de 2000, e analisadas em microscópio de transmissão JEM 100-SX. A maior parte das espécies foi registrada em águas euhalinas e mixopolihalinas durante a primavera e o verão, nenhuma no outono e poucas (quatro) no inverno. A ausência de coanoflagelados nas estações mais protegidas deve-se a influência da água doce, e na estação da praia deve-se, provavelmente, a forte ação das ondas. As espécies, provavelmente cosmopolitas, Pleurasiga minima, Cosmoeca norvegica, C. ventricosa and Parvicorbicula circularis ocorreram na primavera ou no verão no canal principal do estuário e na área costeira, enquanto Stephanoeca diplocostata, que aparentemente prefere baixas temperaturas, foi registrada no inverno. Calotheca alata e Campyloacantha spinifera são principalmente de ambientes temperados e estiveram presentes na primavera. Uma espécie nova, Diplotheca tricyclica, foi registrada na área do canal principal do estuário, no verão de 1999, em águas de alta salinidade. Abstract in english The biodiversity of marine heterotrophic protists is poorly known in the South Atlantic coastal zone (~32 °S) especially regarding the nanoflagellates. The presence of loricate choanoflagellates was reported for the first time in the Patos Lagoon estuary and the adjacent coastal zone. Seventeen spec [...] ies of eleven genera of loricate choanoflagellates were observed between October 1998 and May 2000 in fixed water samples (lugol's solution + glutaraldehyde) in a JEM 100-SX transmission electron microscope. Most species were recorded in euhaline and mixopolyhaline waters during the spring and summer, none in autumn and a few (four) in winter. The absence of choanoflagellates at the more sheltered inshore stations is due freshwater influence, and at the beach station, probably due the strong wave action. The probably cosmopolitan species Pleurasiga minima, Cosmoeca norvegica, C. ventricosa and Parvicorbicula circularis were present in spring or summer in the estuary channel and coastal area while Stephanoeca diplocostata which apparently prefers lower temperature, was recorded in winter. Calotheca alata and Campyloacantha spinifera are mainly temperate species and were present in spring. The new species Diplotheca tricyclica was recorded at the estuary channel in the summer 1999, in high salinity water.

  15. The kinetics of phase transformations during the tempering of HS6-5-2 steel

    Directory of Open Access Journals (Sweden)

    J. Krawczyk

    2009-02-01

    Full Text Available Purpose: This work contains a detailed description of the kinetics of phase transformations during tempering of hardened HS6-5-2 high-speed steel. Moreover, the microstructure development in tested samples, reflecting the extend of the phase transformations during tempering, was discussed too.Design/methodology/approach: CHT diagram, illustrating the kinetics of phase transformations during continuous heating (tempering from as-quenched state of investigated steel, was elaborated using a DT 1000 dilatometer of a French company Adamel. The influence of the heating rate on the retained austenite transformation as well as the results of threefold tempering at 560ºC were also determined.Findings: Heating of the investigated steel from the as-quenched state resulted in the occurrence of 4 primary transformations: precipitation of ? carbide, M3C precipitation, transformation of retained austenite and precipitation of alloy carbides of MC and M2C type. It was shown that in the quenched high-speed steels a part of retained austenite is already transformed during heating for tempering, but its significant part is transformed only during cooling after tempering as well as during consecutive heatings for temperings. Examination of the microstructure of investigated steel, mainly focused on microstructural development relating to the advancement of transformations during continuous tempering, showed an adequacy of the microstructural changes to CHT diagrams.Research limitations/implications: The new CHT diagram of investigated steel was determined.Practical implications: The obtained CHT diagram may be used to design new technologies of tempering of this steel.Originality/value: The new CHT diagram.

  16. Study on temper embrittlement control technique in steel 12Cr1MoV

    Science.gov (United States)

    Li, Qing-Fen; Chen, Hong-Bin; Long, Ping; Cui, Xiu-Fang

    2006-03-01

    Failure may occur catastrophically by fracture along grain boundaries when temper embrittlement induced by non-equilibrium, grain-boundary segregation (NGS) of phosphorus atoms. Temper embrittlement control technique based on the theory of NGS and deformation induced phase transformation in low-alloy steel, 12CrlMoV (which is used in steam pipeline of ships), was experimentally investigated. A single-pass hot rolling process by using a Gleeble-1500 system was performed, and the experimental results showed that the grain sizes were obviously affected by the deforming temperature, strains, strain rate and the quenching cooling rate. Temper embrittlement may be controlled and obviously improved by grain refinement.

  17. Communication: Simulated tempering with fast on-the-fly weight determination

    Science.gov (United States)

    Nguyen, Phuong H.; Okamoto, Yuko; Derreumaux, Philippe

    2013-02-01

    We propose an efficient method to enhance sampling in computer simulations by combining the simulated tempering algorithm with a fast on-the-fly weight determination scheme. The weights are self-updated via a trapezoid rule during the simulated tempering simulation. With our proposed scheme, simulated tempering requires neither prior trial simulations nor complicated update schemes. The advantage of our method over replica exchange molecular dynamics has been demonstrated with the study of the folding of the 20-residue alanine peptide and the aggregation of a trimer formed by the Alzheimer's peptide fragment A?16-22.

  18. Tempering of Martensitic Stainless Steel with 0.6 w/o Nitogen and /or Carbon

    OpenAIRE

    Berns, H; Gavriljuk, V.

    1997-01-01

    Martensitic stainless high nitrogen steels are used for advanced bearings because of their superior corrosion resistance and hot hardness. Therefore the tempering behaviour of steels SC, SN and SNC with close to 15 w/o Cr, 1 w/o Mo and 0.6 w/o C, N or C+N, respectively, was investigated. Secondary hardening is enhanced by nitrogen, which also increase the content of retained austenite and its resistance to tempering especially in SNC. During tempering [MATH], [MATH] and M7C3-carbides precipit...

  19. Improvement of Laser Deposited High Alloyed Powder Metallurgical Tool Steel by a Post-tempering Treatment

    Science.gov (United States)

    Leunda, J.; Navas, V. García; Soriano, C.; Sanz, C.

    Laser cladding process of a high alloyed powder metallurgical tool steel was studied for die repairing purposes. The low hardness obtained after the deposition process was improved by later tempering cycles, achieving crack free coatings with hardness well above 700 HV. The effect of different post tempering cycles was investigated in order to determine the optimal temperature range. The microstructure of the samples was studied using optical and scanning electron microscope and the volumetric ratio of retained austenite was determined by X-ray diffraction. The tempering effect was mainly evaluated through cross-section microhardness profiles.

  20. Bacterial diversity in the South Adriatic Sea during a strong, deep winter convection year.

    Science.gov (United States)

    Korlevi?, M; Pop Ristova, P; Gari?, R; Amann, R; Orli?, S

    2015-03-01

    The South Adriatic Sea is the deepest part of the Adriatic Sea and represents a key area for both the Adriatic Sea and the deep eastern Mediterranean. It has a role in dense water formation for the eastern Mediterranean deep circulation cell, and it represents an entry point for water masses originating from the Ionian Sea. The biodiversity and seasonality of bacterial picoplankton before, during, and after deep winter convection in the oligotrophic South Adriatic waters were assessed by combining comparative 16S rRNA sequence analysis and catalyzed reporter deposition-fluorescence in situ hybridization (CARD-FISH). The picoplankton communities reached their maximum abundance in the spring euphotic zone when the maximum value of the chlorophyll a in response to deep winter convection was recorded. The communities were dominated by Bacteria, while Archaea were a minor constituent. A seasonality of bacterial richness and diversity was observed, with minimum values occurring during the winter convection and spring postconvection periods and maximum values occurring under summer stratified conditions. The SAR11 clade was the main constituent of the bacterial communities and reached the maximum abundance in the euphotic zone in spring after the convection episode. Cyanobacteria were the second most abundant group, and their abundance strongly depended on the convection event, when minimal cyanobacterial abundance was observed. In spring and autumn, the euphotic zone was characterized by Bacteroidetes and Gammaproteobacteria. Bacteroidetes clades NS2b, NS4, and NS5 and the gammaproteobacterial SAR86 clade were detected to co-occur with phytoplankton blooms. The SAR324, SAR202, and SAR406 clades were present in the deep layer, exhibiting different seasonal variations in abundance. Overall, our data demonstrate that the abundances of particular bacterial clades and the overall bacterial richness and diversity are greatly impacted by strong winter convection. PMID:25548042

  1. Winter Olympics Physics and Biomechanics

    Science.gov (United States)

    Many Winter Olympic sports are greatly dependent on technique, engineering, and/or gravity. For example, during luge, while gravity is accelerating the sled up to 80 mph down the track, the slider must use good technique to steer the sled and minimize air resistance. To excel in these type of sports, it is helpful to have a full appreciation of physics and biomechanics. Physics is a broad field which includes mechanics, electricity, magnetism, optics, etc., and biomechanics is the study of the mechanics of living systems. In the module we will use the sports of luge and figure skating to teach you four basic mechanical concepts: linear kinematics, linear dynamics, projectile motion, and conservation of angular momentum. In addition, we have developed a glossary which defines and illustrates all the physics terminology you will need to complete this module.

  2. Ovarian changes during the reproductive cycle of the Tupinambis merianae lizard raised in a temperate environment

    Directory of Open Access Journals (Sweden)

    Manes, Mario E.

    2007-03-01

    Full Text Available El ciclo reproductor de hembras de Tupinambis merianae criadas en ambiente templado consiste de tres fases gonadales: previtelogénica, vitelogénica y postovulatoria o lútea. Durante la fase previtelogénica, que ocupa gran parte del verano, el otoño e invierno, los ovarios son pequeños, pesan menos de 4 g y contienen solamente folículos no vitelogénicos, los cuales se desarrollan lentamente a partir de los nidos germinales, alcanzando unos 5 mm de diámetro. Debido a una maduración gonadal asincrónica entre ambos sexos, las cópulas acontecen cuando los ovarios son aún previtelogénicos. Luego sobreviene una corta e intensa vitelogénesis, durante la cual los folículos crecen uniformemente incrementando unas 6 veces su diámetro (cerca de 30 mm, mientras que la masa ovárica total alcanza unos 400 g. El proceso culmina entre los 15 y 20 días, con una ovulación generalizada y la subsiguiente oviposición. Como consecuencia, los ovarios postovulatorios aparecen reducidos a unos 5 g, con una superficie casi enteramente cubierta de cicatrices foliculares, las cuales pronto desarrollan cuerpos lúteos. La detención del ciclo ovárico, con atresia folicular previtelogénica masiva, como resultado del aislamiento de las hembras, permite concluir sobre la existencia de estímulos sexuales promotores de la vitelogénesis. The reproductive cycle of Tupinambis merianae females raised in a temperate environment consists of three gonadal phases: previtellogenic, vitellogenic and postovulatory or luteal phases. During the previtellogenic phase, which takes great part of the summer, autumn and winter, the ovaries are small, weigh less than 4 g, and contain only nonvitellogenic follicles, which develop slowly from germinal beds, until they are almost 5 mm diameter. Due to an asynchronous gonadal maturation in both sexes, matings occur when ovaries are still previtellogenic. Then comes a short and intense vitellogenesis, during which follicles grow steadily increasing around 6 times their diameter (close to 30 mm, while the total ovarian mass reaches almost 400 g. The process culminates between the 15th and 20th day, with a widespread ovulation and a subsequent oviposition. As a consequence, postovulatory ovaries appear reduced to 5 g approximately, with a surface almost entirely covered with follicular scars, which soon developed luteal bodies. Blockade of the ovarian cycle, with a massive previtellogenic follicular atresia, as a result of females isolation leads to conclude on the existence of sexual stimuli promoting vitellogenesis.

  3. Moraine formation during an advance/retreat cycle at a temperate alpine glacier

    Science.gov (United States)

    Brook, M.; Quincey, D.; Winkler, S.

    2012-04-01

    Mountain glaciers are highly sensitive to variations in temperature and precipitation, and so moraine records from such systems are strong indicators of climate change. Due to the prevailing trend of retreat of the majority of mountain glaciers globally over the last few decades, there are limited opportunities to observe moraine formation, especially at temperate alpine glaciers. In the Southern Alps of New Zealand, while glaciers have all experienced a major retreat since the late 19th century, within this loss of ice mass, there has been a distinct variance in individual glacier response. Indeed, while Tasman Glacier, the longest glacier in the Southern Alps has thinned and entered into the current phase of calving retreat in the early 1990s, the steeper, more responsive glaciers to the west of the Main Divide, such as Franz Josef and Fox Glacier have experienced more elaborate advance/retreat phases. We focus on moraine formation at Fox Glacier, a c. 12.5 km long valley glacier terminating at 300 m above sea level. Fox Glacier retreated substantially since the 1930s, before advancing 800 m between the mid-1980s and 1999. A minor retreat then followed until 2005, succeeded by a 300 m re-advance until 2007-8. Continued retreat and down-wasting has since followed. Superimposed on this alternating advance/retreat cycle, have been minor winter re-advances. Sedimentological and morphological information were combined with detailed observations, historical photos and recent time-lapse photography of the terminus. Characteristics of several modes of moraine formation have been observed: (1) the late 20th century advance culminated in a broad time-lapse imagery identified thrusting and subsequent melt-out of fine-grained englacial material along reverse faults intersecting the terminal face as a significant contributor to the subdued terminal moraines forming during the most recent phase of recent recession; (4) collapse of lateral moraines due to post-2008 down-wasting is now proceeding. Overall, even short-term preservation of glacigenic sediment-landform associations on the Fox Glacier sandur is limited by the glacial meltwater regime, with lateral migration of the proglacial river continually reworking morainic material.

  4. Synchrotron micro-diffraction analysis of the microstructure of cryogenically treated high performance tool steels prior to and after tempering

    International Nuclear Information System (INIS)

    The phase transformation and strain changes within cryogenically (-196 deg. C) treated high performance tool steels (AISI H13) before and after tempering have been examined using both laboratory XRD and synchrotron micro-diffraction. The martensitic unit cell was found to have very low tetragonality as expected for low carbon steel. Tempering resulted in the diffusion of excess carbon out of the martensite phase and consequent unit cell shrinkage. In addition on tempering the martensite became more homogeneous as compared to the same samples prior to tempering. For cryogenically treated samples, the effect was most pronounced for the rapidly cooled sample which was the least homogenous sample prior to tempering but was the most homogenous sample after tempering. This suggests that the considerable degree of disorder resulting from rapid cryogenic cooling results in the beneficial release of micro-stresses on tempering thus possibly resulting in the improved wear resistance and durability observed for cryogenically treated tool steels.

  5. Special Economic Zones In India

    OpenAIRE

    Dilip Khanderao Patil

    2013-01-01

    A Special Economic Zone (SEZ) is a geographical region that has economic laws that are more liberal than a country's typical economic laws. The category 'SEZ' covers a broad range of more specific zone types, including Free Trade Zones (FTZ), Export processing zones (EPZ), Free Zones (FZ), Industrial Estates (IE), Free ports, Urban Enterprise Zones and others. Usually the goal of a structure is to increase foreign direct investment by foreign investors; typically an international business or ...

  6. Numerical simulation of a rare winter hailstorm event over Delhi, India on 17 January 2013

    KAUST Repository

    Chevuturi, A.

    2014-12-19

    This study analyzes the cause of the rare occurrence of a winter hailstorm over New Delhi/NCR (National Capital Region), India. The absence of increased surface temperature or low level of moisture incursion during winter cannot generate the deep convection required for sustaining a hailstorm. Consequently, NCR shows very few cases of hailstorms in the months of December-January-February, making the winter hail formation a question of interest. For this study, a recent winter hailstorm event on 17 January 2013 (16:00–18:00 UTC) occurring over NCR is investigated. The storm is simulated using the Weather Research and Forecasting (WRF) model with the Goddard Cumulus Ensemble (GCE) microphysics scheme with two different options: hail and graupel. The aim of the study is to understand and describe the cause of hailstorm event during over NCR with a comparative analysis of the two options of GCE microphysics. Upon evaluating the model simulations, it is observed that the hail option shows a more similar precipitation intensity with the Tropical Rainfall Measuring Mission (TRMM) observation than the graupel option does, and it is able to simulate hail precipitation. Using the model-simulated output with the hail option; detailed investigation on understanding the dynamics of hailstorm is performed. The analysis based on a numerical simulation suggests that the deep instability in the atmospheric column led to the formation of hailstones as the cloud formation reached up to the glaciated zone promoting ice nucleation. In winters, such instability conditions rarely form due to low level available potential energy and moisture incursion along with upper level baroclinic instability due to the presence of a western disturbance (WD). Such rare positioning is found to be lowering the tropopause with increased temperature gradient, leading to winter hailstorm formation.

  7. Numerical simulation of a rare winter hailstorm event over Delhi, India on 17 January 2013

    Science.gov (United States)

    Chevuturi, A.; Dimri, A. P.; Gunturu, U. B.

    2014-12-01

    This study analyzes the cause of the rare occurrence of a winter hailstorm over New Delhi/NCR (National Capital Region), India. The absence of increased surface temperature or low level of moisture incursion during winter cannot generate the deep convection required for sustaining a hailstorm. Consequently, NCR shows very few cases of hailstorms in the months of December-January-February, making the winter hail formation a question of interest. For this study, a recent winter hailstorm event on 17 January 2013 (16:00-18:00 UTC) occurring over NCR is investigated. The storm is simulated using the Weather Research and Forecasting (WRF) model with the Goddard Cumulus Ensemble (GCE) microphysics scheme with two different options: hail and graupel. The aim of the study is to understand and describe the cause of hailstorm event during over NCR with a comparative analysis of the two options of GCE microphysics. Upon evaluating the model simulations, it is observed that the hail option shows a more similar precipitation intensity with the Tropical Rainfall Measuring Mission (TRMM) observation than the graupel option does, and it is able to simulate hail precipitation. Using the model-simulated output with the hail option; detailed investigation on understanding the dynamics of hailstorm is performed. The analysis based on a numerical simulation suggests that the deep instability in the atmospheric column led to the formation of hailstones as the cloud formation reached up to the glaciated zone promoting ice nucleation. In winters, such instability conditions rarely form due to low level available potential energy and moisture incursion along with upper level baroclinic instability due to the presence of a western disturbance (WD). Such rare positioning is found to be lowering the tropopause with increased temperature gradient, leading to winter hailstorm formation.

  8. Numerical simulation of a winter hailstorm event over Delhi, India on 17 January 2013

    Science.gov (United States)

    Chevuturi, A.; Dimri, A. P.; Gunturu, U. B.

    2014-09-01

    This study analyzes the cause of rare occurrence of winter hailstorm over New Delhi/NCR (National Capital Region), India. The absence of increased surface temperature or low level of moisture incursion during winter cannot generate the deep convection required for sustaining a hailstorm. Consequently, NCR shows very few cases of hailstorms in the months of December-January-February, making the winter hail formation a question of interest. For this study, recent winter hailstorm event on 17 January 2013 (16:00-18:00 UTC) occurring over NCR is investigated. The storm is simulated using Weather Research and Forecasting (WRF) model with Goddard Cumulus Ensemble (GCE) microphysics scheme with two different options, hail or graupel. The aim of the study is to understand and describe the cause of hailstorm event during over NCR with comparative analysis of the two options of GCE microphysics. On evaluating the model simulations, it is observed that hail option shows similar precipitation intensity with TRMM observation than the graupel option and is able to simulate hail precipitation. Using the model simulated output with hail option; detailed investigation on understanding the dynamics of hailstorm is performed. The analysis based on numerical simulation suggests that the deep instability in the atmospheric column led to the formation of hailstones as the cloud formation reached upto the glaciated zone promoting ice nucleation. In winters, such instability conditions rarely form due to low level available potential energy and moisture incursion along with upper level baroclinic instability due to the presence of WD. Such rare positioning is found to be lowering the tropopause with increased temperature gradient, leading to winter hailstorm formation.

  9. Numerical simulation of a winter hailstorm event over Delhi, India on 17 January 2013

    Directory of Open Access Journals (Sweden)

    A. Chevuturi

    2014-09-01

    Full Text Available This study analyzes the cause of rare occurrence of winter hailstorm over New Delhi/NCR (National Capital Region, India. The absence of increased surface temperature or low level of moisture incursion during winter cannot generate the deep convection required for sustaining a hailstorm. Consequently, NCR shows very few cases of hailstorms in the months of December-January-February, making the winter hail formation a question of interest. For this study, recent winter hailstorm event on 17 January 2013 (16:00–18:00 UTC occurring over NCR is investigated. The storm is simulated using Weather Research and Forecasting (WRF model with Goddard Cumulus Ensemble (GCE microphysics scheme with two different options, hail or graupel. The aim of the study is to understand and describe the cause of hailstorm event during over NCR with comparative analysis of the two options of GCE microphysics. On evaluating the model simulations, it is observed that hail option shows similar precipitation intensity with TRMM observation than the graupel option and is able to simulate hail precipitation. Using the model simulated output with hail option; detailed investigation on understanding the dynamics of hailstorm is performed. The analysis based on numerical simulation suggests that the deep instability in the atmospheric column led to the formation of hailstones as the cloud formation reached upto the glaciated zone promoting ice nucleation. In winters, such instability conditions rarely form due to low level available potential energy and moisture incursion along with upper level baroclinic instability due to the presence of WD. Such rare positioning is found to be lowering the tropopause with increased temperature gradient, leading to winter hailstorm formation.

  10. Half a Century of Schladming Winter Schools

    International Nuclear Information System (INIS)

    The Schladming Winter Schools have started as early as in 1962. Over the times the yearly Schools have closely followed the actual developments in nuclear, particle, or more generally, in theoretical physics. Several new achievements have first been dealt with in length in the lectures at the Schladming Winter School. It has seen very prominent lecturers, among them a series of Nobel laureates (some of them reporting on their works even before they got their Nobel prizes). I will try to highlight the role of the Schladming Winter Schools in pro- mulgating new developments of theoretical physics in depth at the lectures given over the past 50 years. (author)

  11. Effect of Tempering Temperature and Time on Strength and Hardness of Ductile Cast Iron

    Science.gov (United States)

    Kumar, R.; Behera, R. K.; Sen, S.

    2015-02-01

    The effects of tempering temperature and time on the mechanical properties of ductile cast iron is investigated in the current work. The specimens were austenitized at 900°C for 120 minutes and then quenched in mineral oil at room temperature. Immediately after quenching the specimens were tempered at 400°C and 200°C for 60min, 90min, and 120min. In the tempering temperature range of 200°C-400°C, there is sudden increase in impact strength, ductility and toughness of the materials, as the temperature and time increase. The UTS drops initially, and hardness of materials will depends on amount of phase of martensitic and retained austenitic and graphite nodules. In this work alloying elements also effected the microstructure of the specimen. And due to increase tempering time the amount of martensitic phase will decrease and retained austenitic phase will increase, retained austenitic phase is softer then martensitic so hardness will decrease.

  12. Spring molybdenum enrichment in scallop shells: a potential tracer of diatom productivity in temperate coastal environments (Brittany, NW France

    Directory of Open Access Journals (Sweden)

    A. Barats

    2010-01-01

    Full Text Available Skeletal molybdenum/calcium ([Mo]/[Ca]shell ratios were examined in shells of the Great Scallop Pecten maximus collected in temperate coastal environments of Western Europe (42 to 49° N. These ratios were determined by quantitative LA-ICP-MS analyses of daily striae taken every third day (i.e. a temporal resolution of 3 days in 36 flat valves (2-years old; 3 shells/year. Variations of ([Mo]/[Ca]shell ratios were significant and reproducible for scallops from the same population, from different years (1998–2004 and temperate coastal locations (NW France. The [Mo]/[Ca]shell ratios exhibit typical profiles characterized by a background content, below the detection limit for this method (<0.003 ?mol/mol for most of the shell growth period, which is punctuated by a significant transient enrichment (0.031–2.1 ?mol/mol mainly occurring from May to June. The Bay of Brest (France was investigated in particular because of its long term observations on scallop communities, environmental variables, and high resolution analyses of dissolved Mo in bottom seawater in 2000. In 2000, dissolved Mo exhibited a significant increase in concentration just preceding the maximum ([Mo]/[Ca]shell ratio. Both the intense monitoring survey in 2000 and over the 7-year period indicates that the ([Mo]/[Ca]shell maximum is directly influenced by spring changes of environmental conditions at the sediment water interface (SWI, occurring subsequent to the intense and periodic spring bloom. Spring maxima of ([Mo]/[Ca]shell ratios are closely correlated to the extent of silicic acid and nitrate depletion in seawater between winter and late spring (r2=0.878 and 0.780, p<0.05, n=6 that reflects diatom uptake and productivity in the Bay of Brest. The Mo inputs in bottom waters and subsequent shell enrichment are thus suggested to be directly or indirectly influenced by such biogenic material input at the SWI. The [Mo]/[Ca]shell records thus reveal unexpected biogeochemical cycles of Mo influenced by coastal spring productivity, faithfully recorded in scallop shells.

  13. Comparison of the segregation behavior between tempered martensite and tempered bainite in Ni-Cr-Mo high strength low alloy RPV steel

    International Nuclear Information System (INIS)

    SA508 Gr.4N Ni-Cr-Mo low alloy steel has an superior fracture toughness and strength, compared to commercial Mn-Mo-Ni low alloy RPV steel SA508 Gr.3. Higher strength and fracture toughness of low alloy steels could be obtained by adding Ni and Cr. So several were performed on researches on SA508 Gr.4N low alloy steel for a RPV application. The operation temperature and term of a reactor pressure vessel is more than 300 .deg. C and over 40 years. Therefore, in order to apply the SA508 Gr.4N low alloy steel for a reactor pressure vessel, the resistance of thermal embrittlement in the high temperature range including temper embrittlement is required. S. Raoul reported that the susceptibility to temper embrittlement was increasing a function of the cooling rate in SA533 steel, which suggests the martensitic microstructures resulting from increased cooling rates are more susceptible to temper embrittlement. However, this result has not been proved yet. So the comparison of temper embrittlement behavior was made between martensitic microstructure and bainitic microstructure with a viewpoint of boundary features in SA508 Gr.4N, which have mixture of tempered bainite/martensite. We have compared temper embrittlement behaviors of SA508 Gr.4N low alloy steel with changing volume fraction of martensite. The mechanical properties of these low alloy steels were evaluated after a long-term heat treatment. Then, the the segregated boundaries were observed and segregation behavior wa were observed and segregation behavior was analyzed by AES. In order to compare the misorientation distributions of model alloys, grain boundary structures were measured with EBSD

  14. Comparison of the segregation behavior between tempered martensite and tempered bainite in Ni-Cr-Mo high strength low alloy RPV steel

    Energy Technology Data Exchange (ETDEWEB)

    Park, Sang Gyu; Kim, Min Chul; Kim, Hyung Jun; Lee, Bong Sang [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

    2012-05-15

    SA508 Gr.4N Ni-Cr-Mo low alloy steel has an superior fracture toughness and strength, compared to commercial Mn-Mo-Ni low alloy RPV steel SA508 Gr.3. Higher strength and fracture toughness of low alloy steels could be obtained by adding Ni and Cr. So several were performed on researches on SA508 Gr.4N low alloy steel for a RPV application. The operation temperature and term of a reactor pressure vessel is more than 300 .deg. C and over 40 years. Therefore, in order to apply the SA508 Gr.4N low alloy steel for a reactor pressure vessel, the resistance of thermal embrittlement in the high temperature range including temper embrittlement is required. S. Raoul reported that the susceptibility to temper embrittlement was increasing a function of the cooling rate in SA533 steel, which suggests the martensitic microstructures resulting from increased cooling rates are more susceptible to temper embrittlement. However, this result has not been proved yet. So the comparison of temper embrittlement behavior was made between martensitic microstructure and bainitic microstructure with a viewpoint of boundary features in SA508 Gr.4N, which have mixture of tempered bainite/martensite. We have compared temper embrittlement behaviors of SA508 Gr.4N low alloy steel with changing volume fraction of martensite. The mechanical properties of these low alloy steels were evaluated after a long-term heat treatment. Then, the the segregated boundaries were observed and segregation behavior was analyzed by AES. In order to compare the misorientation distributions of model alloys, grain boundary structures were measured with EBSD

  15. : Seizure onset zone imaging

    OpenAIRE

    David, Olivier; Blauwblomme, Thomas; Job, Anne-Sophie; Chabardès, Stéphan; Hoffmann, Dominique,; Minotti, Lorella; Kahane, Philippe

    2011-01-01

    Stereo-electroencephalography is used to localize the seizure onset zone and connected neuronal networks in surgical candidates suffering from intractable focal epilepsy. The concept of an epileptogenicity index has been proposed recently to represent the likelihood of various regions being part of the seizure onset zone. It quantifies low-voltage fast activity, the electrophysiological signature of seizure onset usually assessed visually by neurologists. Here, we revisit epileptogenicity in ...

  16. Immune zones in leprosy

    OpenAIRE

    Murthy P; Hegde Rajesh; Chandrashekar H

    2009-01-01

    Leprosy affects mainly those areas of skin which have a relatively lower temperature and are more exposed to trauma. Certain zones like scalp, palms and soles, genitalia, groins, axillae, eyelids, transverse band of skin over lumboscaral area, midline of back and perineum have been described to be immune to the development of lesions in leprosy. But clinical, histological and bacteriological evidence of involvement of these so called immune zones though infrequent have been documented. Hence,...

  17. Cascadia Subduction Zone

    Science.gov (United States)

    Frankel, Arthur D.; Petersen, Mark D.

    2008-01-01

    The geometry and recurrence times of large earthquakes associated with the Cascadia Subduction Zone (CSZ) were discussed and debated at a March 28-29, 2006 Pacific Northwest workshop for the USGS National Seismic Hazard Maps. The CSZ is modeled from Cape Mendocino in California to Vancouver Island in British Columbia. We include the same geometry and weighting scheme as was used in the 2002 model (Frankel and others, 2002) based on thermal constraints (Fig. 1; Fluck and others, 1997 and a reexamination by Wang et al., 2003, Fig. 11, eastern edge of intermediate shading). This scheme includes four possibilities for the lower (eastern) limit of seismic rupture: the base of elastic zone (weight 0.1), the base of transition zone (weight 0.2), the midpoint of the transition zone (weight 0.2), and a model with a long north-south segment at 123.8? W in the southern and central portions of the CSZ, with a dogleg to the northwest in the northern portion of the zone (weight 0.5). The latter model was derived from the approximate average longitude of the contour of the 30 km depth of the CSZ as modeled by Fluck et al. (1997). A global study of the maximum depth of thrust earthquakes on subduction zones by Tichelaar and Ruff (1993) indicated maximum depths of about 40 km for most of the subduction zones studied, although the Mexican subduction zone had a maximum depth of about 25 km (R. LaForge, pers. comm., 2006). The recent inversion of GPS data by McCaffrey et al. (2007) shows a significant amount of coupling (a coupling factor of 0.2-0.3) as far east as 123.8? West in some portions of the CSZ. Both of these lines of evidence lend support to the model with a north-south segment at 123.8? W.

  18. Tempering treatment effect on mechanical properties of F82H steel doped with boron and nitrogen

    International Nuclear Information System (INIS)

    Effects of tempering treatment on mechanical properties and microstructures have been studied for martensitic steel F82H doped with 60 ppm B and 200 ppm N (F82H + B + N). The tempering treatments were performed at 700-780degC after the normalizing treatment at 1000degC. Yield stress of the F82H + B + N steel tempered at 700, 750 and 780degC was 740, 580 and 500 MPa, respectively, and ductile-brittle transition temperature (DBTT) of the specimens was -55, -85 and -85degC, respectively. The areal density of dislocations decreased from 1.1 x 1014 to 2.5 x 1013m-2 with increasing tempering temperature from 700 to 780degC. The number density of precipitates decreased with increasing tempering temperature from 700 to 750degC, while the number density was almost equivalent as increasing tempering temperature from 750 to 780degC. The results indicate that the change of DBTT, depending on tempering temperature, is related with the change of yield strength, size and number density of carbides. Hardening behavior of the F82H + B + N steel irradiated by 10.5 MeV Fe3+ to 10 dpa at 360degC has been also studied by using a micro-indentator. The micro-hardness of the F82H + B + N steel tempered at 780degC was changed from 3.6 to 4.8 GPa by the irradiation. Because hardening behavior of the F82H + B + N steel was found to be similar with that of F82H non-doped, doping effects of B on irradiation hardening were suppressed by co-doped of B andening were suppressed by co-doped of B and N. (author)

  19. Three phase crystallography and solute distribution analysis during residual austenite decomposition in tempered nanocrystalline bainitic steels

    Energy Technology Data Exchange (ETDEWEB)

    Caballero, F.G. [Centro Nacional de Investigaciones Metalúrgicas (CENIM-CSIC), Avda Gregorio del Amo, 8, Madrid E-28040 (Spain); Yen, Hung-Wei [Department of Materials Science and Engineering, National Taiwan University, 1, Roosevelt Rd. Sec. 4, Taipei 10617, Taiwan (China); Australian Centre for Microscopy and Microanalysis, The University of Sydney, NSW 2006 (Australia); Miller, M.K. [Oak Ridge National Laboratory (ORNL), Materials Science and Technology Division, Oak Ridge, TN 37831-6139 (United States); Cornide, J. [Centro Nacional de Investigaciones Metalúrgicas (CENIM-CSIC), Avda Gregorio del Amo, 8, Madrid E-28040 (Spain); Chang, Hsiao-Tzu [Department of Materials Science and Engineering, National Taiwan University, 1, Roosevelt Rd. Sec. 4, Taipei 10617, Taiwan (China); Garcia-Mateo, C. [Centro Nacional de Investigaciones Metalúrgicas (CENIM-CSIC), Avda Gregorio del Amo, 8, Madrid E-28040 (Spain); Yang, Jer-Ren [Department of Materials Science and Engineering, National Taiwan University, 1, Roosevelt Rd. Sec. 4, Taipei 10617, Taiwan (China)

    2014-02-15

    Interphase carbide precipitation due to austenite decomposition was investigated by high resolution transmission electron microscopy and atom probe tomography in tempered nanostructured bainitic steels. Results showed that cementite (?) forms by a paraequilibrium transformation mechanism at the bainitic ferrite–austenite interface with a simultaneous three phase crystallographic orientation relationship. - Highlights: • Interphase carbide precipitation due to austenite decomposition • Tempered nanostructured bainitic steels • High resolution transmission electron microscopy and atom probe tomography • Paraequilibrium ? with three phase crystallographic orientation relationship.

  20. Mechanisms promoting higher growth rate in arctic than in temperate shorebirds

    OpenAIRE

    Schekkerman, H.; Tulp, I.Y.M.; Piersma, T.; Visser, G H

    2003-01-01

    We compared prefledging growth, energy expenditure, and time budgets in the arctic-breeding red knot (Calidris canutus) to those in temperate shorebirds, to investigate how arctic chicks achieve a high growth rate despite energetic difficulties associated with precocial development in a cold climate. Growth rate of knot chicks was very high compared to other, mainly temperate, shorebirds of their size, but strongly correlated with weather-induced and seasonal variation in availability of inve...

  1. Constitutive behavior and fracture properties of tempered martensitic steels for nuclear applications: experiments and modelling

    OpenAIRE

    Bonadé, Raùl Alejandro

    2006-01-01

    In this study, the tensile and fracture properties and the microstructure of the reduced-activation tempered martensitic steel Eurofer97 have been investigated. This technical alloy is a 9%Cr steel developed within the European fusion material research program. To a lesser extend, the plastic flow properties of a equiaxed ferritic Fe9%Cr model alloy were also studied for comparison with those of the tempered martensitic structure. The main objectives of this work are described hereafter: to ...

  2. Heat and cold shock protein synthesis in arctic and temperate strains of rhizobia.

    OpenAIRE

    Cloutier, J.; Pre?vost, D.; Nadeau, P.; Antoun, H.

    1992-01-01

    We compared heat shock proteins (HSPs) and cold shock proteins (CSPs) produced by different species of Rhizobium having different growth temperature ranges. Several HSPs and CSPs were induced when cells of three arctic (psychrotrophic) and three temperate (mesophilic) strains of rhizobia were shifted from their optimal growth temperatures (arctic, 25 degrees C; temperate, 30 degrees C) to shock temperatures outside their growth temperature ranges. At heat shock temperatures, three major HSPs ...

  3. Trophic diversity of the otter (Lutra lutra L.) in temperate and Mediterranean freshwater habitats

    OpenAIRE

    Clavero, Miguel; Prenda, J.; Delibes, M.

    2003-01-01

    Aim To analyse the geographical patterns in the composition and diversity of otter’s (Lutra lutra L.) diet and their relationship with climatic characteristics. Location European freshwater habitats under Mediterranean and temperate climatic regimes. Methods Thirty-seven otter diet studies were reviewed, twenty-one from temperate and sixteen from Mediterranean areas. All studies were based on spraint analysis and their results expressed as relative frequency of oc...

  4. Genome-Wide DNA Polymorphisms in Seven Rice Cultivars of Temperate and Tropical Japonica Groups

    OpenAIRE

    Arai-kichise, Yuko; Shiwa, Yuh; Ebana, Kaworu; Shibata-hatta, Mari; Yoshikawa, Hirofumi; Yano, Masahiro; Wakasa, Kyo

    2014-01-01

    Elucidation of the rice genome is expected to broaden our understanding of genes related to the agronomic characteristics and the genetic relationship among cultivars. In this study, we conducted whole-genome sequencings of 6 cultivars, including 5 temperate japonica cultivars and 1 tropical japonica cultivar (Moroberekan), by using next-generation sequencing (NGS) with Nipponbare genome as a reference. The temperate japonica cultivars contained 2 sake brewing (Yamadanishiki and Gohyakumangok...

  5. DETERMINATION OF THE OPTIMAL TEMPERING TEMPERATURE IN HARD FACING OF THE FORGING DIES

    OpenAIRE

    Milan Mutavdži?; Vuki? Lazi?; Dragan Milosavljevi?; Srbislav Aleksandrovi?; Nikolic?, Ruz?ica R.; Rajko ?uki?; Gordana Bogdanovi?

    2012-01-01

    Here is analyzed selection of the optimal technology for heat treatment during the reparation of the damaged forging dies. Those tools are manufactured from alloyed tool steels for operation at elevated temperatures. Those steels are prone to self-hardening, so in reparatory hard-facing they must be preheated, additionally heated and tempered. During the tempering, in temperature interval 500-600°C, a secondary increase of hardness and decrease of impact toughness occurs, the so-called rever...

  6. Estimating Vertical Distribution of Vegetation Cover in Temperate Heterogeneous Forests Using Airborne Laser Scanning Data

    OpenAIRE

    Keiko Ioki; Junichi Imanishi; Takeshi Sasaki; Youngkeun Song; Yukihiro Morimoto; Hisashi Hasegawa

    2012-01-01

    Vertical structure is important for understanding forest environment, yet difficult to characterize, especially in temperate heterogeneous forests where the structure is complex. This study used data from a small-footprint airborne laser scanning (ALS) to estimate vegetation coverage in four stratum ranges in a warm temperate forest in Japan: >12 m, 8 - 12 m, 4 - 8 m, and 0 - 4 m in height. Field data were collected in 17 broad-leaved and 12 coniferous sample plots, consisting of the propo...

  7. Three phase crystallography and solute distribution analysis during residual austenite decomposition in tempered nanocrystalline bainitic steels

    International Nuclear Information System (INIS)

    Interphase carbide precipitation due to austenite decomposition was investigated by high resolution transmission electron microscopy and atom probe tomography in tempered nanostructured bainitic steels. Results showed that cementite (?) forms by a paraequilibrium transformation mechanism at the bainitic ferrite–austenite interface with a simultaneous three phase crystallographic orientation relationship. - Highlights: • Interphase carbide precipitation due to austenite decomposition • Tempered nanostructured bainitic steels • High resolution transmission electron microscopy and atom probe tomography • Paraequilibrium ? with three phase crystallographic orientation relationship

  8. Influence of nonmartensitic transformation products on mechanical properties of tempered martensite

    Science.gov (United States)

    Hodge, J M; Lankford, W T

    1952-01-01

    The influence of nonmartensitic transformations products on the mechanical properties of tempered martensite is presented for samples of a SAE 4340 steel, partially isothermally transformed to specific high-temperature transformation products and quenched and tempered to hardness values of from 25 to 40 Rockwell c. The effects of upper bainite in amounts of 1,5, 10, 20 and 50 percent, of 5 percent ferrite, and of 5 percent pearlite on the tensile, impact, and fatigue properties are evaluated. (author)

  9. Tempering kinetics of the X10CrMoVNb9-1 martensitic steel

    International Nuclear Information System (INIS)

    This work is part of a collaborative study between CEA-Saclay and LMT-Cachan on the numerical simulation of multi-pass GTA-Welding of thick specimens made of X10CrMoVNb9-1 (ASTM 387 or T91) steel. The final objective of this paper is to exhibit the prediction capabilities of an improved version of the Thermo-Metallurgical-Mechanical 'TMM' model for X10CrMoVNb9-1 martensitic steel (initially developed by G.-M. Roux). In this paper, focus is made on the modelling of the martensite tempering due to the complex thermal loadings induced by the multi-pass process. Herein, it has been chosen to study the tempering kinetics via the evolution of the free carbon content or, conversely, the carbides precipitation overall fraction, growth and dissolution. Thermo-Electric Power (TEP) measurements as well as hardening measurements have been used to investigate the tempering phenomenon. Measurements are fast to perform and are not very sensitive to the geometry of the material (in opposite to resistivity measurements). A phenomenological tempering Model was developed and identified from several tests at constant tempering temperatures ranging from 550 degrees C up to 750 degrees C. The improved TMM model including this tempering model was used to perform the 2D finite element analysis of the 16-pass GTA welding process of a narrow groove butt-weld. The predictions are favourably compared with the 'real' microstructure. (authors)(authors)

  10. Influence of Mo addition on the tempered properties of 13Cr martensitic stainless steel

    International Nuclear Information System (INIS)

    In order to investigate the effect of Mo addition on the mechanical properties of 13Cr-0.2C martensitic stainless steel, tensile test and Charpy V-notch test were performed after tempering at the temperature range of 200?700 .deg. C following austenitizing at 1100 .deg. C. The yield strength and hardness of the steel were increased with the increase of Mo content at all tempering conditions, because Mo causes retardation of precipitation and coarsening of carbides and solid solution strengthening of matrix. Except 500 .deg. C of tempering temperature, the Charpy impact energy was significantly increased with Mo content and showed the highest value at 1.5 wt% addition. The increase of impact energy of the steel containing Mo is thought to be caused by ?-ferrite formed in the tempered martensitic matrix. At 500 .deg. C tempering, Charpy impact energy was decreased drastically due to temper embrittlement and it was not possible to prevent it even though Mo was added up to 1.5 wt%

  11. Wear Characteristics and Mechanisms of H13 Steel with Various Tempered Structures

    Science.gov (United States)

    Cui, X. H.; Wang, S. Q.; Wei, M. X.; Yang, Z. R.

    2011-08-01

    Wear tests of H13 steel with various tempering microstructures were performed under atmospheric conditions at room temperature (RT), 200 °C, and 400 °C. The wear characteristics and wear mechanisms of various tempered microstructures of the steel were focused by investigating the structure, morphology, and composition of the worn surfaces. Under atmospheric conditions at RT, 200 °C, and 400 °C, adhesive wear, mild oxidation wear, and oxidation wear prevailed, respectively. The wear rate at 200 °C was substantially lower than those at RT and 400 °C due to the protection of tribo-oxides. In mild oxidation wear, the tempered microstructures of the steel presented almost no obvious influence on the wear resistance. However, in adhesive wear and oxidation wear, the wear resistance strongly depended on the tempered microstructures of the steel. The steel tempered at 600-650 °C presented pronouncedly lower wear rates than the one tempered at 200-550 or 700 °C. It can be suggested that the wear resistance of the steel was closely related with its fracture resistance.

  12. Overview of climatic effects of nuclear winter

    International Nuclear Information System (INIS)

    A general description of the climatic effects of a nuclear war are presented. This paper offers a short history of the subject, a discussion of relevant parameters and physical processes, and a description of plausible nuclear winter scenario. 9 refs

  13. Unusial winter 2011/2012 in Slovakia.

    Czech Academy of Sciences Publication Activity Database

    Faško, P.; Lapin, M.; Matejovi?, P.; Pecho, Jozef

    2012-01-01

    Ro?. 15, ?. 1 (2012), s. 19-26. ISSN 1335-339X Institutional support: RVO:68378289 Keywords : winter characteristics * climate variabilit * climate change * global warming Subject RIV: DG - Athmosphere Sciences, Meteorology

  14. Mesoscale Aspects of Winter Weather Forecasting Topics

    Science.gov (United States)

    COMET

    2003-10-12

    The Mesoscale Aspects of Winter Weather Forecasting effort is comprised of a growing series of in-depth case exercises bundled with supporting topics. This site provides access to the supporting topics seperate from the case exercises.

  15. A climatology of planetary wave-driven mesospheric inversion layers in the extratropical winter

    Science.gov (United States)

    France, J. A.; Harvey, V. L.; Randall, C. E.; Collins, R. L.; Smith, A. K.; Peck, E. D.; Fang, X.

    2015-01-01

    inversion layers (MILs) are a useful diagnostic to simultaneously investigate middle atmosphere radiation, chemistry, and dynamics in high-top general circulation models. Climatologies of long-lived extratropical winter MILs observed by the Microwave Limb Sounder (MLS) and the Sounding of the Atmosphere using Broadband Emission Radiometry (SABER) satellite instruments are compared to MILs in the Whole Atmosphere Community Climate Model (WACCM). In general, MIL location, amplitude, and thickness statistics in WACCM are in good agreement with the observations, though WACCM middle- and high-latitude winter MILs occur 30%-50% more often than in MLS and SABER. This work suggests that planetary wave-driven MILs may form as high as 90 km. In the winter, MILs display a wave-1 pattern in both hemispheres, forming most often over the region where the climatological winter stratospheric anticyclones occur. These MILs are driven by the decay of vertically propagating planetary waves in the mesospheric surf zone in both observations and in the model. At the base of polar inversions there is climatological local ascent and cooling situated atop the stratospheric anticyclones, which enhances the cold base of the MILs near 60 km and 120°E longitude.

  16. Combining ability of tropical and temperate inbred lines of popcorn.

    Science.gov (United States)

    da Silva, V Q R; do Amaral Júnior, A T; Gonçalves, L S A; Freitas Júnior, S P; Candido, L S; Vittorazzi, C; Moterle, L M; Vieira, R A; Scapim, C A

    2010-01-01

    In Brazil, using combining ability of popcorn genotypes to achieve superior hybrids has been unsuccessful because the local genotypes are all members of the same heterotic group. To overcome this constraint, 10 lines (P(1) to P(10)) with different adaptations to tropical or temperate edaphoclimatic environments were used to obtain 45 F(1) hybrids in a complete diallel. These hybrids and three controls were evaluated in two environments in Rio de Janeiro State. Grain yield (GY), popping expansion (PE), plant height (PH), ear height (EH), and days to silking (FL) were evaluated in randomized complete blocks with three replications. Significant differences between genotypes (P

  17. Temperate bacteriophages collected by outer membrane vesicles in Komagataeibacter intermedius.

    Science.gov (United States)

    Kharina, Alla; Podolich, Olga; Faidiuk, Iuliia; Zaika, Sergiy; Haidak, Andriy; Kukharenko, Olga; Zaets, Iryna; Tovkach, Fedor; Reva, Oleg; Kremenskoy, Maxim; Kozyrovska, Natalia

    2015-04-01

    The acetic acid bacteria have mainly relevance for bacterial cellulose production and fermented bio-products manufacture. The purpose of this study was to identify temperate bacteriophages in a cellulose-producing bacterial strain Komagataeibacter intermedius IMBG180. Prophages from K. intermedius IMBG180 were induced with mitomycin C and nalidixic acid. Transmission electron microscopy analysis exhibited tailed bacteriophages belonging to Myoviridae. A PCR assay targeting the capsid gene of the myoviruses proved phylogenetic position of induced phages. Nalidixic acid was poor inducer of prophages, however, it induced the OMV-like particles release. Size of OMVs depended on an antibiotic applied for phage induction and varied in the range of 30-80 and 120-200?nm. Inside some of them, tails of phages have been visible. Under conditions, inducing prophages, OMVs acted as the collectors of formed phage particles, using outer membrane receptors for phage detection (in this case, outer membrane siderophore receptor), and fulfilled therefore "a cleaning," as well as defensive functions, preventing bacteriophage spread outside population. This is the first description of myoviruses affiliated to K. intermedius, as well as outer membrane vesicles interaction with phages within this host. PMID:25589010

  18. Temperate Drosophila preserve cardiac function at low temperature

    DEFF Research Database (Denmark)

    Andersen, Jonas Lembcke; MacMillan, Heath Andrew

    2015-01-01

    Most insects are chill susceptible and will enter a coma if exposed to sufficiently low temperature. This chill coma has been associated with a failure of the neuromuscular system. Insect heart rate (HR) is determined by intrinsic regulation (muscle pacemaker) with extrinsic (nervous and humoral) input. By examining the continually active heart of five Drosophila species with markedly different cold tolerance, we investigated whether cardiac performance is related to the whole animal critical thermal minimum (CTmin). Further, to separate the effects of cold on extrinsic and intrinsic regulators of HR, we measured HR under similar conditions in decapitated flies as well as amputated abdomens of Drosophila montana. Cardiac performance was assessed from break points in HR-temperature relationship (Arrhenius break point, ABP) and from the HR cessation temperature. Among the five species, we found strong relationships for both the HR-ABP and HR cessation temperatures to whole animal CTmin, such that temperate Drosophila species maintained cardiac function at considerably lower temperatures than their tropical congeners. Hearts of amputated abdomens, with reduced extrinsic input, had a higher thermal sensitivity and a significantly lower break point temperature, suggesting that central neuronal input is important for stimulating HR at low temperatures.

  19. Giant Eunicid Polychaetes (Annelida in shallow tropical and temperate seas

    Directory of Open Access Journals (Sweden)

    Sergio I Salazar-Vallejo

    2011-12-01

    Full Text Available Some species of Eunice might reach giant size, often being longer than 2m, and they are known from tropical and temperate seas. Despite their large size and recent internet notoriety, there remain some taxonomic problems in large-sized eunicids, especially since original descriptions were brief and type materials are often missing. As a mean to encourage the solution of this situation, we review the historical progress in the taxonomy of the group, including some comments on generic and specific delineation, and recommend some critical steps to solve the current confusion. These ideally would include collecting in type localities, evaluate ontogenetic morphological changes, and generate some molecular analysis to complement the morphological approach. Rev. Biol. Trop. 59 (4: 1463-1474. Epub 2011 December 01.Algunas species de Eunice pueden alcanzar tamaño gigantesco, a menudo sobrepasan los 2m de largo, y se conocen de mares tropicales y templados. A pesar de su gran tamaño y de su reciente notoriedad en Internet, todavía hay problemas taxonómicos entre los eunícidos gigantes, especialmente dado que las descripciones originales fueron breves y a menudo se carece de materiales tipo. Para incentivar la solución del problema, revisamos el desarrollo histórico de la taxonomía del grupo y se incluyen algunos comentarios sobre la delineación de los géneros y de las especies y recomendamos algunos pasos críticos para alcanzar este fin. Idealmente, esto incluiría recolectar en las localidades tipo, evaluar cambios morfológicos durante la ontogenia y generar algunos análisis moleculares para complementar el enfoque morfológico.

  20. Restoration of a temperate reef: Effects on the fish community

    DEFF Research Database (Denmark)

    StØttrup, Josianne; Stenberg, Claus

    2014-01-01

    The extraction of large boulders from coastal reefs for construction of harbours and coastal protection has led to habitat degradation for local fish populations through the destruction of cavernous reefs and changes in macroalgal cover resulting from a loss of substrate. The temperate reef at Læsø Trindel in Kattegat, Denmark, has now been re-established with the aim of restoring the reef’s historical structure and function. The effects of the restoration on the local fish community are reported here. Fishing surveys using gillnets and fyke nets were conducted before the restoration (2007) and four years after the restoration of the reef (2012). Species of the family Labridae, which have a high affinity for rocky reefs, dominated both before and after the restoration. Commercially important species such as cod Gadus morhua, and saithe Pollachius virens, occurred infrequently in the catches in 2007 but were significantly more abundant in the catches in 2012. Cods were especially attracted to the shallow part of the reef that was restored by adding stones. For some species, such as ballan wrasse Labrus bergylta, and cod, the proportion of larger individuals increased after the restoration. The findings highlight the importance of reef habitats for fish communities and the need for their protection

  1. Wave propagation in temperate plasmas consisting of n ion species

    International Nuclear Information System (INIS)

    Plane wave propagation in temperate plasmas consisting of n ion species is calculated. Analytical results are given for collisionless n species plasmas of arbitrary composition. Refractive index and damping are calculated numerically for plasmas including collisions of any kind and at arbitrary angles of propagation. At angles other than 900 to the externally applied magnetic field there are two simultaneously propagating waves showing resonances at the cyclotron frequencies of the ions involved, and being separated by n-1 ion-ion-hybrid cutoffs. Strong particle coupling through high ion collision rates reduces the n cyclotron resonances to new combined, mass weighted and frequency shifted cyclotron resonance frequencies. In the ion cyclotron frequency range one wave will propagate at right angle to the external magnetic field showing n-1 ion-ion-hybrid resonances and n-1 hybrid cutoffs. The hybrid resonance frequencies lie close to the cyclotron frequencies of the minority ions. In the neighbourhood of the resonances, the ion collisions affect damping of the wave considerably more than electron collisions. (orig.)

  2. Winter huddling groups in the striped mouse.

    OpenAIRE

    Schradin, C; Schubert, M.; Pillay, N.

    2006-01-01

    Huddling is a strategy to avoid heat loss and thus save energy and is often observed in birds and rodents, which, because of their small body size, are prone to relatively high heat loss. Huddling might thus explain group-living in some cases, such as the winter huddling groups described for several northern hemisphere rodents. Here we describe winter huddling groups in an African rodent, the striped mouse (Rhabdomys pumilio (Sparrman, 1784)), from the Succulent Karoo of South Africa. Striped...

  3. The Species Richness of Vascular Plants and Amphibia in Major Plant Communities in Temperate to Tropical Australia: Relationship with Annual Biomass Production

    International Nuclear Information System (INIS)

    Aerodynamic fluxes (frictional, thermal, evaporative) in the atmosphere as it flows over and through a plant community determine the Foliage Projective Covers and eco-morphological attributes of new leaves developed annually in overstorey and understorey strata. The number of leaves produced on vertical foliage shoots depends on available soil water and nutrients, also ambient temperature, during this short growth season. Stem density (number of stems per hectare) and species richness (number of species per hectare) in the overstorey of major Floristic Groups are correlated with annual shoot growth (ASG, t ha-1) in that stratum. Species richness in the overstorey increases in the climatic gradient from the arid to the humid zone as well as with increasing air temperatures (about 10 degree C) from temperate to tropical Australia. Species richness in the understorey is highest in plant communities in temperate Australia, decreasing in the temperature gradient towards the tropics. As with other major plant and animal groups within an ecosystem, the species richness of Amphibia is correlated with the amount of solar energy fixed (per annum) by the major plant formation in the regional photosynthetic potential determined by the foliage shoots (ASG, t ha-1) produced annually in the overstorey.

  4. Radiative and precipitation controls on root zone soil moisture spectra

    Science.gov (United States)

    Nakai, Taro; Katul, Gabriel G.; Kotani, Ayumi; Igarashi, Yasunori; Ohta, Takeshi; Suzuki, Masakazu; Kumagai, Tomo'omi

    2014-11-01

    Temporal variability in root zone soil moisture content (w) exhibits a Lorentzian spectrum with memory dictated by a damping term when forced with white-noise precipitation. In the context of regional dimming, radiation and precipitation variability are needed to reproduce w trends prompting interest in how the w memory is altered by radiative forcing. A hierarchy of models that sequentially introduce the spectrum of precipitation, net radiation, and the effect of w on evaporative and drainage losses was used to analyze the spectrum of w at subtropical and temperate forested sites. Reproducing the w spectra at long time scales necessitated simultaneous precipitation and net radiation measurements depending on site conditions. The w memory inferred from observed w spectra was 25-38 days, larger than that determined from maximum wet evapotranspiration and field capacity. The w memory can be reasonably inferred from the Lorentzian spectrum when precipitation and evapotranspiration are in phase.

  5. Winter road access to projected works in the diversion of the Little Whale River

    International Nuclear Information System (INIS)

    The Great Whale hydroelectric complex in northern Quebec will require diversion of the Little Whale River, involving construction of dams 40 m and 30 m high and a canal 600 m long. The main mode of access to the construction sites will be a winter road, supplemented by an airfield designed for large-capacity aircraft. The method used by Hydro-Quebec in its environmental assessment of the winter road project is described. This method comprises five steps: delimitation of the study zone; establishment of a road corridor of choice by successively eliminating territory according to given constraints; description of the physical and biological environment; determination and optimization of the road route; and evaluation of potential impacts, along with establishment of measures to mitigate those impacts. The optimal routing is determined on the basis of criteria such as the presence of permafrost, the nature of the soils, avoidance of slopes steeper than 10%, and the depth and width of ice crossings

  6. The zone of tundra

    International Nuclear Information System (INIS)

    Peculiarities of radionuclide migration in the zone of tundra are considered. High 232Th content, high 232Th/238U values at low 238U and 226Ra concentrations in rocks are shown to be characteristic for the chosen zone. Data on methods of 238U and 232Th determination in natural waters, as well as content of radionuclides in water and bottom sediments are presented. Formation of soils under the conditions of mountain tundra is shown to result in noticeable redistribution of radioactive elements as well as all their isotopes. Data on U, Th, Ra isotope content in different plants and certain organs of plants are presented. Principal statistical parameters both of content of certain U, Th, Ra isotopes and their isotope relations on the whole by soil and vegetation of the investigated region are presented. When characterizing storage of isotopes of different elements in vegetation of the zone of tundra it is necessary to note that the dependence 226Ra(228Ra)>228Th>227Th>230Th>232Th>238U>234U is typical for it. Intensity of radionuclide inclusion in the biogenic migration cycle in the zone of tundra is higher than in the zone of taiga

  7. CANDIDATE PLANETS IN THE HABITABLE ZONES OF KEPLER STARS

    Energy Technology Data Exchange (ETDEWEB)

    Gaidos, Eric, E-mail: gaidos@hawaii.edu [Department of Geology and Geophysics, University of Hawai' i at Manoa, Honolulu, HI 96822 (United States)

    2013-06-20

    A key goal of the Kepler mission is the discovery of Earth-size transiting planets in ''habitable zones'' where stellar irradiance maintains a temperate climate on an Earth-like planet. Robust estimates of planet radius and irradiance require accurate stellar parameters, but most Kepler systems are faint, making spectroscopy difficult and prioritization of targets desirable. The parameters of 2035 host stars were estimated by Bayesian analysis and the probabilities p{sub HZ} that 2738 candidate or confirmed planets orbit in the habitable zone were calculated. Dartmouth Stellar Evolution Program models were compared to photometry from the Kepler Input Catalog, priors for stellar mass, age, metallicity and distance, and planet transit duration. The analysis yielded probability density functions for calculating confidence intervals of planet radius and stellar irradiance, as well as p{sub HZ}. Sixty-two planets have p{sub HZ} > 0.5 and a most probable stellar irradiance within habitable zone limits. Fourteen of these have radii less than twice the Earth; the objects most resembling Earth in terms of radius and irradiance are KOIs 2626.01 and 3010.01, which orbit late K/M-type dwarf stars. The fraction of Kepler dwarf stars with Earth-size planets in the habitable zone ({eta}{sub Circled-Plus }) is 0.46, with a 95% confidence interval of 0.31-0.64. Parallaxes from the Gaia mission will reduce uncertainties by more than a factor of five and permit definitive assignments of transiting planets to the habitable zones of Kepler stars.

  8. CANDIDATE PLANETS IN THE HABITABLE ZONES OF KEPLER STARS

    International Nuclear Information System (INIS)

    A key goal of the Kepler mission is the discovery of Earth-size transiting planets in ''habitable zones'' where stellar irradiance maintains a temperate climate on an Earth-like planet. Robust estimates of planet radius and irradiance require accurate stellar parameters, but most Kepler systems are faint, making spectroscopy difficult and prioritization of targets desirable. The parameters of 2035 host stars were estimated by Bayesian analysis and the probabilities pHZ that 2738 candidate or confirmed planets orbit in the habitable zone were calculated. Dartmouth Stellar Evolution Program models were compared to photometry from the Kepler Input Catalog, priors for stellar mass, age, metallicity and distance, and planet transit duration. The analysis yielded probability density functions for calculating confidence intervals of planet radius and stellar irradiance, as well as pHZ. Sixty-two planets have pHZ > 0.5 and a most probable stellar irradiance within habitable zone limits. Fourteen of these have radii less than twice the Earth; the objects most resembling Earth in terms of radius and irradiance are KOIs 2626.01 and 3010.01, which orbit late K/M-type dwarf stars. The fraction of Kepler dwarf stars with Earth-size planets in the habitable zone (??) is 0.46, with a 95% confidence interval of 0.31-0.64. Parallaxes from the Gaia mission will reduce uncertainties by more than a factor of five and permit definitive assignmr of five and permit definitive assignments of transiting planets to the habitable zones of Kepler stars.

  9. Spring Temperatures Alone Cannot Explain Timing of Budburst of Boreal-Temperate Tree Species under Experimental Warming

    Science.gov (United States)

    Montgomery, R. A.; Reich, P. B.; Rich, R. L.; Stefanski, A.

    2011-12-01

    Phenology, the timing of seasonal biological events such as budburst, blossom dates, bird migration and insect development, is critical to understanding species interactions (e.g. pollination, herbivory); determines growing season length in many (i.e. seasonal) terrestrial ecosystems; and can play a role in determining species range limits. There is ample evidence that plant and animal phenology has changed in recent decades. For trees in seasonally cold climates, change is most commonly manifested as earlier budburst, likely caused by earlier onset of warming temperatures in spring. Indeed, it is often assumed that one of the major phenological responses of temperate and boreal forest ecosystems to climate change will be earlier leafing and concomitantly, a longer growing season. However, spring warming interacts with other factors such as winter chilling and photoperiod to determine timing of spring leafing. For example, warmer winters could reduce the duration and amount of chilling experienced by dormant buds and lead to delayed budburst. Despite knowledge that such interactions exist, we know little about the interactive mechanisms by which various cues influence budburst in forest tree species or whether species differ in sensitivity to those cues. This gap hinders our ability to predict phenological responses and their ecological impacts under future climate scenarios. Over the past three years, we have conducted studies of leafing phenology, germination, photosynthesis, respiration, and growth of seedlings of ten boreal-temperate tree species subjected to experimental warming using infrared heat lamps and soil heating cables. Seedlings were planted into plots receiving ambient, +1.8°C or +3.6°C temperature treatments in open, aspen forest at the Cloquet Forestry Center, Cloquet, MN, USA (46°31' N, 92°30' W, 386 m a.s.l.; 4.5°C MAT, 807 mm MAP). While all species responded to warming by advancing the absolute date of budburst, several lines of evidence support the role of other factors, namely photoperiod or chilling, in co-determining observed responses. First, a number of species showed non-linear responses in absolute day of year of budburst across levels of warming: specifically, some species did not advance the date of budburst in +3.6°C compared to +1.8°C treatments. Second, if warming was the only cue for budburst, then one would expect that the plants would break bud after the same amount of warming regardless of treatment (i.e. at the same thermal time) and thus they would reach that threshold earlier in the warmed treatments (i.e. earlier absolute time). This was not observed. Instead, using thermal time to budburst rather than absolute date of budburst, we found that all species required more warming to break bud in warmed compared to unwarmed treatments. Lastly, when we examined the relationship between thermal time to budburst and chill days, we found that longer thermal time to budburst was associated with reduced chilling. Taken together, these three lines of evidence suggest that spring warming is not the only cue for budburst. Future research and modelling must recognize the role of other cues.

  10. Temporal dynamics of soil aggregates and microbial parameters in permanent and recently established grasslands in the temperate zone

    Science.gov (United States)

    Linsler, Deborah; Taube, Friedhelm; Geisseler, Daniel; Joergensen, Rainer Georg; Ludwig, Bernard

    2015-04-01

    While changes over time in soil aggregation or microbial parameters are well studied for arable soils, much less is known about such temporal variations in grassland soils. The objective of the present study was to determine the changes that occur within one year (between October 2010 and October 2011) for water-stable aggregate, microbial biomass carbon (Cmic) and ergosterol (as a proxy for fungal biomass) concentrations of a sandy soil under a permanent and recently established grasslands The analyzed treatments were (i) permanent grassland, (ii) grassland re-established after tillage of previous permanent grassland, and (iii) grassland established on arable land (both in September 2010). Temporal variations were found for the aggregate distribution and ergosterol concentration in the permanent grassland. For instance, the concentration of large macroaggregates (>2000 ?m) in the surface soil (0-10 cm) varied strongly, with the highest concentration (mean ± standard error) in October 2011 (666 ± 12 g kg-1) and a 3.2-fold lower concentration in May 2011. An explanation could be less rainfall and decreasing soil moisture contents in May compared to October, which may have decreased the stability of this fraction. A multiple linear regression analysis showed that the large macroaggregate concentration was well described (R2=0.60) by the gravimetric moisture content, the Cmic concentration and the pH. After the tillage event in the grassland and the subsequent grassland renovation, the concentrations of large macroaggregate, Cmic and ergosterol decreased in the surface soil, while no difference was found in the soil profile (0-40 cm). In the first year after the conversion of arable land into grassland, the concentrations of Cmic and ergosterol increased by a factor of 1.4 and 3.3, respectively, in the surface soil layer, while the macroaggregate concentration was not affected. This study indicates that the aggregate dynamic in grassland is not only affected by management but also by environmental conditions. The fungal biomass seems to be more sensitive to changes in environmental conditions or grassland management than the microbial biomass because the variations for the ergosterol concentrations were stronger than those for the Cmic concentrations.

  11. Quantification of Methane Bubbles Ebullition in Freshwater Reservoirs of Temperate Zone using Sonar Working with 120 kHz Frequency.

    Czech Academy of Sciences Publication Activity Database

    Frouzová, Jaroslava; Tušer, Michal; Stanovský, Petr

    Vol. 16. - : -, 2014, s. 11398. ISBN N. [European Geosciences Union. Vienna (AT), 27.04.2014-02.05.2014] R&D Projects: GA ?R GAP504/12/1186 Institutional support: RVO:67985858 ; RVO:60077344 Keywords : ebullition * freshwater * methane Subject RIV: EH - Ecology, Behaviour http://meetingorganizer.copernicus.org/EGU2014/EGU2014-11398.pdf

  12. Biodiversity in temperate European grasslands: origin and conservation.

    OpenAIRE

    Pärtel, Meelis; Bruun, Hans Henrik; Sammul, Marek

    2005-01-01

    Northern Europe is in the forest zone, but wild megaherbivores have maintained grass-dominated vegetation here for the last 1.8 million years. Continuity of the grassland biome through glacialinterglacial cycles and connection to steppe vegetation has resulted in the evolution, immigration, and survival of a large number of grassland species. During the last millennia the effect of wild ungulates has been replaced by domestic grazers and hay making, and the persistence of grasslan...

  13. Free energy calculations of a proton transfer reaction by simulated tempering umbrella sampling first principles molecular dynamics simulations

    OpenAIRE

    Mori, Yoshiharu; Okamoto, Yuko

    2012-01-01

    A new simulated tempering method, which is referred to as simulated tempering umbrella sampling, for calculating the free energy of chemical reactions is proposed. First principles molecular dynamics simulations with this simulated tempering were performed in order to study the intramolecular proton transfer reaction of malonaldehyde in aqueous solution. Conformational sampling in reaction coordinate space can be easily enhanced with this method, and the free energy along a ...

  14. The influence of kinetics phase transformation during tempering on the mechanical properties of HS6-5-2 steel

    OpenAIRE

    J. Pacyna; Ba?a, P

    2008-01-01

    Purpose: The reason for writing this paper was to describe the kinetics of phase transformations during tempering and the evaluation of the influence of pre-tempering on the properties of HS6-5-2 steel after principal tempering. Moreover, the differences in hardness of samples of the investigated steel in relationship to the heating rate were evaluated. The microstructure development in tested samples, reflecting the extend of the phase transformations ...

  15. Winter barley mutants created in the Ukraine

    International Nuclear Information System (INIS)

    Full text: Increasing fodder and protein production is one of the objectives of the development of agriculture in Ukraine. Higher productivity of fodder crops, due to new highly productive varieties, is the means to meet this aim. Winter barley is an important crop for fodder purposes. The climate of the Ukraine is favourable for growing this crop. The areas used for the growth of winter barley are however, small (500,000-550,000 ha) and there is a shortage of good quality varieties. The main aim of the work was therefore to create new varieties of highly productive winter barley, of good quality. The new varieties and mutation lines of winter barley were created under the influence of water solutions of N-nitroso-N-methylurea (NMH - 0,012, 0,005%), N-nitroso-N-ethylurea (NEH - 0,05; 0.025; 0,012%) ethyleneimine (EI - 0,02; 0,01; 0,005%) on winter barley seeds of the varieties of local and foreign selections. On the basis of many years of investigations (1984-94) the following mutations were described: hard-grained, winter-hardiness, earliness, middle-maturity, late-maturity, wide and large leaves, narrow leaves, multinodal, great number of leaves, great number of flowers, strong stem (lodging resistant), tallness, semi-dwarfness, dwarfness, and high productivity. Particularly valuable are mutants with high productivity of green bulk. Their potential yield is 70 t/ha. As a result of the work two varieties of winter barley 'Shyrokolysty' and 'Kormovy' were released into the State register of plant varieties of the Ukraine. The other valuable mutant genotypes are used in cross breeding programmes. (author)

  16. Seasonal variation in physical and biological factors that influence sediment porosity on a temperate mudflat: Willapa Bay, Washington, USA

    Science.gov (United States)

    Wheatcroft, Robert A.; Sanders, Rhea D.; Law, Brent A.

    2013-06-01

    A field study of a temperate mudflat in Willapa Bay, Washington was conducted to determine whether seasonal variation in physical forcings (e.g., temperature, rainfall, insolation) coupled with variation in key biological properties (e.g., seagrass and microphytobenthos abundance) would result in measurable changes in seabed porosity. On two mudflats and in a nearby secondary channel, replicate samples for surficial grain size, chlorophyll a content, and seagrass (Zostera japonica) shoot density were obtained at roughly 7-wk intervals for one year starting in November 2009. In addition, high-resolution profiles of porosity in the upper ˜9cm of the seabed were measured using an in situ resistivity profiler. Ancillary meteorological and river discharge data were obtained from nearby stations operated by Washington State University and the U. S. Geological Survey, respectively. Despite significant seasonal variation in seagrass abundance (0 to >3000 shoots m-2), a less dramatic, but still significant variation in chlorophyll a content, as well as seasonal changes in physical forcings, the near-surface porosity of the flats was a normally consolidated bed that remained steady throughout the year. In contrast, porosity of the channel often departed from a normally consolidated profile, with evidence for both erosion and deposition of several centimeters of sediment. These departures did not display a clear seasonal pattern (i.e., deposition in winter, erosion in summer), however, suggesting that the provision and removal of sediment to/from the channels was governed by processes (e.g., channel slumps, rainfall events) occurring on shorter time scales or that there was significant, unresolved small-scale variability.

  17. Giant Eunicid Polychaetes (Annelida) in shallow tropical and temperate seas

    Scientific Electronic Library Online (English)

    Sergio I, Salazar-Vallejo; Luis F, Carrera-Parra; J. Angel, de León-González.

    1463-14-01

    Full Text Available Algunas species de Eunice pueden alcanzar tamaño gigantesco, a menudo sobrepasan los 2m de largo, y se conocen de mares tropicales y templados. A pesar de su gran tamaño y de su reciente notoriedad en Internet, todavía hay problemas taxonómicos entre los eunícidos gigantes, especialmente dado que la [...] s descripciones originales fueron breves y a menudo se carece de materiales tipo. Para incentivar la solución del problema, revisamos el desarrollo histórico de la taxonomía del grupo y se incluyen algunos comentarios sobre la delineación de los géneros y de las especies y recomendamos algunos pasos críticos para alcanzar este fin. Idealmente, esto incluiría recolectar en las localidades tipo, evaluar cambios morfológicos durante la ontogenia y generar algunos análisis moleculares para complementar el enfoque morfológico. Abstract in english Some species of Eunice might reach giant size, often being longer than 2m, and they are known from tropical and temperate seas. Despite their large size and recent internet notoriety, there remain some taxonomic problems in large-sized eunicids, especially since original descriptions were brief and [...] type materials are often missing. As a mean to encourage the solution of this situation, we review the historical progress in the taxonomy of the group, including some comments on generic and specific delineation, and recommend some critical steps to solve the current confusion. These ideally would include collecting in type localities, evaluate ontogenetic morphological changes, and generate some molecular analysis to complement the morphological approach. Rev. Biol. Trop. 59 (4): 1463-1474. Epub 2011 December 01.

  18. Ecosystem respiration depends strongly on photosynthesis in a temperate heath

    DEFF Research Database (Denmark)

    Larsen, Klaus Steenberg; Ibrom, A.

    2007-01-01

    We measured net ecosystem CO2 flux (F-n) and ecosystem respiration (R-E), and estimated gross ecosystem photosynthesis (P-g) by difference, for two years in a temperate heath ecosystem using a chamber method. The exchange rates of carbon were high and of similar magnitude as for productive forest ecosystems with a net ecosystem carbon gain during the second year of 293 +/- 11 g C m(-2) year(-1) showing that the carbon sink strength of heather-dominated ecosystems may be considerable when C. vulgaris is in the building phase of its life cycle. The estimated gross ecosystem photosynthesis and ecosystem respiration from October to March was 22% and 30% of annual flux, respectively, suggesting that both cold-season carbon gain and loss were important in the annual carbon cycle of the ecosystem. Model fit of R-E of a classic, first-order exponential equation related to temperature ( second year; R-2 = 0.65) was improved when the P-g rate was incorporated into the model (second year; R-2 = 0.79), suggesting that daytime R-E increased with increasing photosynthesis. Furthermore, the temperature sensitivity of R-E decreased from apparent Q(10) values of 3.3 to 3.9 by the classic equation to a more realistic Q(10) of 2.5 by the modified model. The model introduces R-photo, which describes the part of respiration being tightly coupled to the photosynthetic rate. It makes up 5% of the assimilated carbon dioxide flux at 0 degrees C and 35% at 20 degrees C implying a high sensitivity of respiration to photosynthesis during summer. The simple model provides an easily applied, non-intrusive tool for investigating seasonal trends in the relationship between ecosystem carbon sequestration and respiration

  19. Production of fermentables and biomass by six temperate fuelcrops

    Energy Technology Data Exchange (ETDEWEB)

    Parrish, D.J.; Gammon, T.C.; Graves, B.

    1985-12-01

    Several potential fuelcrops have been studied individually, but relatively little work has been done to compare the various temperate species in side-by-side trials. The production has been examined of readily fermentable carbohydrates and biomass by six fuelcrop candidates: grain sorghum (Sorghum bicolor), Jerusalem articoke (Helianthus tuberosus), maize (Zea Mays), sugarbeet (Beta vulgaris), sweet potato (Ipomoea batatas) and sweet sorghum (Sorghum bicolor). A randomized complete block design with four replicates was employed at each of three locations that were somewhat diverse in soil type, elevation, growing season length, and 1980 rainfall distribution. Fermentables in the harvestable dry matter were determined colorimetrically following dilute acid plus enzymatic hydrolysis. Overall, sugarbeet was the most prolific producer of fermentables (7.4 Mg/ha); Jerusalem artichoke (5.8 Mg/ha), maize (4.8 Mg/ha) and sweet sorghum stems (5.8 Mg/ha) were statistically equivalent, while sweet potato (4.0 Mg/ha) and grain sorghum (3.8 Mg/ha) were less productive than the other candidates. The crops performed somewhat differently at each location, but the most striking site-specific differences were seen at the site with the coarsest textured soil and driest season. At that location, maize produced the least fermentables (0.6 Mg/ha). Biomass production generally reflected either the amount of time each species was actively growing or limiations to growth associated with drought. No general recommendations are made concerning a preferred temperature fuelcrop. Based on the studies, however, maize may not always be the fuelcrop of choice; others, especially sugarbeet and sweet sorghum (when harvested for grain also), may be superior to maize in productivity of fermentable substrates. 6 tabs., 13 refs.

  20. Radiation budget changes with dry forest clearing in temperate Argentina.

    Science.gov (United States)

    Houspanossian, Javier; Nosetto, Marcelo; Jobbágy, Esteban G

    2013-04-01

    Land cover changes may affect climate and the energy balance of the Earth through their influence on the greenhouse gas composition of the atmosphere (biogeochemical effects) but also through shifts in the physical properties of the land surface (biophysical effects). We explored how the radiation budget changes following the replacement of temperate dry forests by crops in central semiarid Argentina and quantified the biophysical radiative forcing of this transformation. For this purpose, we computed the albedo and surface temperature for a 7-year period (2003-2009) from MODIS imagery at 70 paired sites occupied by native forests and crops and calculated the radiation budget at the tropopause and surface levels using a columnar radiation model parameterized with satellite data. Mean annual black-sky albedo and diurnal surface temperature were 50% and 2.5 °C higher in croplands than in dry forests. These contrasts increased the outgoing shortwave energy flux at the top of the atmosphere in croplands by a quarter (58.4 vs. 45.9 W m(-2) ) which, together with a slight increase in the outgoing longwave flux, yielded a net cooling of -14 W m(-2) . This biophysical cooling effect would be equivalent to a reduction in atmospheric CO2 of 22 Mg C ha(-1) , which involves approximately a quarter to a half of the typical carbon emissions that accompany deforestation in these ecosystems. We showed that the replacement of dry forests by crops in central Argentina has strong biophysical effects on the energy budget which could counterbalance the biogeochemical effects of deforestation. Underestimating or ignoring these biophysical consequences of land-use changes on climate will certainly curtail the effectiveness of many warming mitigation actions, particularly in semiarid regions where high radiation load and smaller active carbon pools would increase the relative importance of biophysical forcing. PMID:23504897

  1. Folding Atomistic Proteins in Explicit Solvent Using Simulated Tempering.

    Science.gov (United States)

    Zhang, Tong; Nguyen, Phuong H; Nasica-Labouze, Jessica; Mu, Yuguang; Derreumaux, Philippe

    2015-06-11

    Following a previous report on a coarse-grained protein model in implicit solvent, we applied simulated tempering (ST) with on-the-fly Helmholtz free energy (weight factors) determination to the folding or aggregation of seven proteins with the CHARMM, OPLS, and AMBER protein, and the SPC and TIP3P water force fields. For efficiency and reliability, we also performed replica exchange molecular dynamics (REMD) simulations on the alanine di- and deca-peptide, and the dimer of the A?16-22 Alzheimer's fragment, and used experimental data and previous simulation results on the chignolin, beta3s, Trp-cage, and WW domain peptides of 10-37 amino acids. The sampling with ST is found to be more efficient than with REMD for a much lower CPU cost. Starting from unfolded or extended conformations, the WW domain and the Trp-cage peptide fold to their NMR structures with a backbone RMSD of 2.0 and 1 Å. Remarkably, the ST simulation explores transient non-native topologies for Trp-cage that have been rarely discussed by other simulations. Our ST simulations also show that the CHARMM22* force field has limitations in describing accurately the beta3s peptide. Taken together, these results open the door to the study of the configurations of single proteins, protein aggregates, and any molecular systems at atomic details in explicit solvent using a single normal CPU. They also demonstrate that our ST scheme can be used with any force field ranging from quantum mechanics to coarse-grain and atomistic. PMID:25985144

  2. Kinship analyses identify fish dispersal events on a temperate coastline.

    Science.gov (United States)

    Schunter, C; Pascual, M; Garza, J C; Raventos, N; Macpherson, E

    2014-06-22

    Connectivity is crucial for the persistence and resilience of marine species, the establishment of networks of marine protected areas and the delineation of fishery management units. In the marine environment, understanding connectivity is still a major challenge, due to the technical difficulties of tracking larvae. Recently, parentage analysis has provided a means to address this question effectively. To be effective, this method requires limited adult movement and extensive sampling of parents, which is often not possible for marine species. An alternative approach that is less sensitive to constraints in parental movement and sampling could be the reconstruction of sibships. Here, we directly measure connectivity and larval dispersal in a temperate marine ecosystem through both analytical approaches. We use data from 178 single nucleotide polymorphism markers to perform parentage and sibship reconstruction of the black-faced blenny (Tripterygion delaisi) from an open coastline in the Mediterranean Sea. Parentage analysis revealed a decrease in dispersal success in the focal area over 1 km distance and approximately 6.5% of the juveniles were identified as self-recruits. Sibship reconstruction analysis found that, in general, full siblings did not recruit together to the same location, and that the largest distance between recruitment locations was much higher (11.5 km) than found for parent-offspring pairs (1.2 km). Direct measurements of dispersal are essential to understanding connectivity patterns in different marine habitats, and show the degree of self-replenishment and sustainability of populations of marine organisms. We demonstrate that sibship reconstruction allows direct measurements of dispersal and family structure in marine species while being more easily applied in those species for which the collection of the parental population is difficult or unfeasible. PMID:24812064

  3. Relationships between bird morphology and prey selection in two sympatric Great Cormorant Phalacrocorax carbo subspecies during winter.

    OpenAIRE

    Fonteneau, Fre?de?ric; Paillisson, Jean-marc; Marion, Loic

    2009-01-01

    Variation in bird morphology (notably sex size dimorphism) has been suggested to contribute to differences in food use between individuals. We explore the hypothesis of food partitioning (diet overlap and prey size selection) in two sympatric subspecies of the Great Cormorant Phalacrocorax carbo with respect to bird morphology (subspecies and sex) in inland French waters. These areas represent a recent and increasing contact zone used as a common non-territorial winter feeding area by the con...

  4. Time spray strategies for Septoria leaf blotch disease progress on winter wheat: The use of forecasting model

    OpenAIRE

    El Jarroudi, Moussa; Giraud, Fre?de?ric; Delfosse, Philippe; Hoffmann, Lucien; Maraite, Henri; Tychon, Bernard

    2010-01-01

    A mechanistic model, PROCULTURE, for assessing in real time the risk of progression of Septoria tritici (teleomorph Mycosphaerella graminicola) on winter wheat (Triticum aestivum L.) was used in Grand-Duchy of Luxemburg over 2003 to 2009 to simulate disease progression in the canopy at four-replicated field experiments located in three villages (Diekirch district: Reuler; Grevenmacher district: Burmerange and Christnach), representative of the different agroclimatological zones of Luxembourg....

  5. Nuclear free zone

    International Nuclear Information System (INIS)

    Health professionals have played a leading role in alerting and educating the public regarding the danger of nuclear war which has been described as the last epidemic our civilization will know. Having convinced most people that the use of nuclear weapons would mean intolerable consequences, groups such as Physicians for Social Responsibility have focused on the second critical question how likely is it that these weapons will be used? The oultlook is grim. This article describes the nuclear free zone movement, explores relevant legal questions, and shows how the political potential of nuclear free zones threatens to open a deep rift in the American constitutional system

  6. The uncomfortable comfort zone

    OpenAIRE

    Carlos Renato Zacharias

    2012-01-01

    Whenever we achieve the satisfaction of our expectations and anxiety dissolves, we feel as if we were in a comfort zone – safe, complete, free from risks and in peace with ourselves. We might even have a little taste of heaven when we feel that we have fulfilled our duty. And as a fact, scientists are entitled to this kind of reward… but not for too long! In science, to enter a comfort zone can be as pleasant as dangerous. On one hand we may have a safe ground available to develo...

  7. Movements and Habitat Use by Temperate-Nesting Canada Geese During the Postbreeding Period in Southern Québec

    Directory of Open Access Journals (Sweden)

    Matthieu Beaumont

    2013-06-01

    Full Text Available Individual behavior that reduces vulnerability to predation can affect population dynamics of animals. Temperate-nesting Canada Geese (Branta canadensis maxima have increased steadily throughout the Atlantic flyway and have become a nuisance in some parts of their range. The objective of our study was to describe movements and habitat use during the postbreeding period of Canada Geese recently established in southern Québec. More specifically, we wanted to determine whether geese were using areas where hunting was allowed to assess the potential of harvest to control the number of geese. We tracked a sample of geese fitted with radio or conventional alphanumeric collars throughout the fall in three zones characterized by different habitats and hunting pressure. Before the hunting season, geese left the breeding area where hunting was allowed to reach suburban areas where firearm discharge was prohibited or hunters’ numbers were low. These postbreeding movements occurred when juveniles were approximately three months old. We observed few local movements among zones once migrant geese from northern breeding populations reached the study area. Radio-collared geese used mainly natural habitats (75.4 ± 2.6%, followed by urban (14.4 ± 2.7%, and agricultural habitats (10.3 ± 0.8%. They were located 73.8 ± 6.2% of the time in areas where hunting was prohibited. Geese that attended their juveniles during brood rearing were more prone to use areas where firearm discharge was restricted than geese that had abandoned or lost their brood. This study shows that under the prevailing regulations, the potential of hunting to manage the increasing breeding population of Canada Geese in southern Québec is limited.

  8. Body Condition in the Eurasian Woodcock Wintering in the West of France: Practical Study for Wildlife Management during Cold Spells

    Directory of Open Access Journals (Sweden)

    Robin, J-P.

    2005-06-01

    Full Text Available The Eurasian woodcock (Scolopax rusticola is one of the most widespread species of the Scolopax genus in temperate regions. However, population levels can be greatly affected by harsh cold spells that led woodcocks to starve by exhaustion of their body fuels. To better understand the vulnerability of woodcocks to such climatic conditions it is of a major importance to determine the amount of their body reserves (both lipids and proteins throughout the wintering season. This was performed on 55 individuals collected by hunters in the western part of France during two consecutive winters under mild weather conditions. Body reserves, that can be mobilised, were determined as the difference between the total amount of lipids and proteins minus the values obtained on starved individuals found dead during previous cold spells. Overall, body reserves did not significantly change over both winters (p > 0.40, the maximal mean value (1539 ± 117 kJ being however reached in January. Storing body fuels would not adversely affect wing and power loading, suggesting that the amount of body reserves would agree with the "starvation-predation trade-off". If woodcocks sit through a cold spell, their mean survival time (or fasting endurance would be 6.5 ± 0.5 days; 25 to 40% of the birds would have a life expectancy of 7-9 days, and about 8 to17% less than 5 days. On the contrary, if woodcocks immediately leave their wintering quarter, they would be able to perform a trip of 740 ± 50 km, 20 to 40% of the woodcocks being able to fly over 750 km. Body mass explains only 47 to 57% of the fasting endurance and flight autonomy variations, and therefore we recommend a further carcass analysis to accurately estimate body condition. These results underscore the suitability of determining the state of body reserves for practical cases of population management and hunting policy during cold spells.

  9. Armco-iron structure in a zone affected by continuous CO2-laser

    International Nuclear Information System (INIS)

    Using the methods of light and electron transmission microscopy, X-ray diffraction and measurement of microhardness the structure of armco-iron (0.035% C) in the region of continuous CO2-laser beam effect has been studied. The detected increase of microhardness in the irradiated zone is conditioned by the procedure of #betta#-?-transformation according to shift mechanism with formation of lath structure (the lath size is 0.4-0.6 ?m). Dependence of microhardness in a laser affected region on the tempering temperature and duration is established

  10. Transformation of goethite/ferrihydrite to hematite and maghemite under temperate humid conditions in Denmark

    DEFF Research Database (Denmark)

    NØrnberg, P.; Finster, K.

    2012-01-01

    At a number of sandy soil sites in Mid Jutland, Denmark, with iron content of 1-2%, very red spots (Munsell colour: dusky red 10R 3/4) of a few square meters are found. These spots are most likely due to burning events. After the fire ashes raised pH. This dispersed silt and clay size soil particles which were then transported with seepage water down into lower soil horizons. These particles contain hematite and maghemite due to influence of the fire. However, a long-standing unresolved question is how hematite and maghemite can also be present along with goethite and ferrihydrite, in the same geographical region, and in extended areas with high iron content (8-40 %) in the topsoil. Hematite and particularly maghemite would normally not be expected to form under the temperate humid Danish climate, but be interpreted as the result of high temperature as found in tropical regions or as seen in soils exposed to fire. The high iron content most likely has its origin in pyrite dissolution in top of the groundwater zone in deeper Miocene deposits. From there Fe2+ is brought to the surface by the groundwater, and in wells oxidized by meeting the atmosphere and precipitated as two line ferrihydrite. This is later transformed into goethite. However, along with these two minerals hematite and maghemite are present in the topsoil around the well area. Forest fires would be a likely explanation to the hematite and maghemite. But a body of evidence argues against these sites having been exposed to fire. 1) The pH in the topsoil is 3.6 - 4.8 and thus not raised by ashes. 2) No charcoal is present. 3) There is no indication of fire outside the high iron content areas. 4) Goethite is present along with hematite and maghemite in microparticles, and the mineralogical zonation produced in a forest fire is not seen. The natural sites contain a uniform mixture of goethite/ferrihydrite, hematite and maghemite down to 20 cm depth. An experimental forest fire left charcoal and ashes at the topsoil, produced high pH, mineral zonationand decreased organic matter content, all of which is in contrast to the natural sites. In the freshly precipitated iron materials iron oxidizers as Gallionella sp. were found, but also iron reducing Geobachter sp.were present. Microbial activity might have influenced the mineral transformations.

  11. The influence of kinetics of phase transformations during tempering on high-speed steels mechanical properties

    Directory of Open Access Journals (Sweden)

    P. Ba?a

    2010-11-01

    Full Text Available Purpose: The main purpose of the presented paper was the determination of the influence of the phase transformation kinetics, at tempering, on the properties of high-speed steels. In order to achieve this aim investigations of the influence of continuous heating and isothermal tempering from the as-quenched state on the investigated steels hardness were performed. The advancement degree change obtained by changing the heating rate and by pre-tempering was applied in strength properties studies.Design/methodology/approach: Due to a high brittleness of tested steels it was decided to test their strength by means of the static bend test. The tests were carried out on 5 samples using the INSTRON testing machine. The microstructure of investigated steels in the as-quenched state was examined by the light microscope Axiovert 200 MAT and the scanning electron microscope Hitachi 3500 N. The measurements of hardness were performed with the Vickers HPO250 apparatus.Findings: Changing heating rates for tempering one can influence steel properties. Better results are achieved when steels are heated up to the tempering temperature with the higher rate. The heating rate increased from 15°C/min to 300°C/min improved the investigated steels bending strength by 8%.Research limitations/implications: Phase transformations at tempering, being diffusive transformations, are characterised by the determined kinetics depending on a temperature and time of heating. Complexity of processes occurring at tempering, as well as the diversity of influencing factors creates the possibility of searching for prolonging the life-span of tools made of high-speed steels. Regardless that only two, well known high-speed steels HS18-0-1 and HS6-5-2 were tested, the obtained results can be referred to the whole group of high-speed steels.Practical implications: On the basis of the obtained results it is possible to select the tempering parameters in such a way as to achieve the optimal combination of strength and plastic properties needed for the anticipated application of the given high-speed steel.Originality/value: This results should be of interest to engineers concerned with designing the new technologies of high-speed steels tempering

  12. Structure and phase composition effect on resistance to tempering and to brittle fracture in 15Kh2NMFA and 10GN2MFA steels

    International Nuclear Information System (INIS)

    The tempering structure of low-carbon perlite steels of 15Kh2NMFA and 10GN2MFA type and effect of carbide phases formed in them on steel resistance to tempering and critical brittleness temperature are studied. The increase of resistance to tempering in the course of formation of uniformly distributed disperse particles of M7C3, M3C, M2C and MC carbides, and also as a result of carbon diffusion mobility in ferrite are found. The maximum resistance to tempering is typical for steel with the structure of tempered lower bainite, the highest resistance to brittle fracture -for steel with the structure of tempered rod martensite

  13. Development of mirrors made of chemically tempered glass foils for future X-ray telescopes

    CERN Document Server

    Salmaso, B; Brizzolari, B; Basso, S; Ghigo, M; Pareschi, G; Spiga, D; Proserpio, L; Suppiger, Y

    2015-01-01

    Thin slumped glass foils are considered good candidates for the realization of future X-ray telescopes with large effective area and high spatial resolution. However, the hot slumping process affects the glass strength, and this can be an issue during the launch of the satellite because of the high kinematical and static loads occurring during that phase. In the present work we have investigated the possible use of Gorilla glass (produced by Corning), a chemical tempered glass that, thanks to its strength characteristics, would be ideal. The un-tempered glass foils were curved by means of an innovative hot slumping technique and subsequently chemically tempered. In this paper we show that the chemical tempering process applied to Gorilla glass foils does not affect the surface micro-roughness of the mirrors. On the other end, the stress introduced by the tempering process causes a reduction in the amplitude of the longitudinal profile errors with a lateral size close to the mirror length. The effect of the ov...

  14. Effect of Tempering Temperature on Mechanical Properties of Medium Carbon Steel

    Directory of Open Access Journals (Sweden)

    S.A Tukur

    2014-03-01

    Full Text Available Un tempered martensitic steels, while very hard are too brittle to be useful for most applications. Most applications require that quenched part be tempered, so as to impact some toughness and further improve ductility. Current work reports and analyzes results of mechanical testing was performed on variously heat treated medium carbon steel samples, to arrive at an optimum heat treatment strategy for judicious combination of hardness and tensile properties. Tensile and hardness test specimens were fabricated using Lathe machine. These samples were subjected to various heat treatment sequences, consisting of full annealing, hardening, oil quenching, and tempering at different temperatures. Heat treated samples were then mechanically tested for hardness (Rockwell and tensile properties (yield strength, ultimate tensile strength, ductility. Mechanical testing of medium carbon steel samples revealed that with increasing temper temperatures: (a hardness first increases to a maximum and then gradually decreases; (b yield strength first decreases, then increases, and then decreases again; (c ultimate strength first increases to a maximum and then steadily decreases; and (d ductility (% elongation increases, and then decreases before continue to increases rather sharply. The optimum heat treatment strategy was found to be at tempering temperature of 250ºC for well balanced mechanical properties.

  15. The Dead Zone: Websites

    Science.gov (United States)

    This Louisiana Sea Grant College Program site offers a collection of websites regarding Gulf of Mexico hypoxia, or "dead zones" created by reduced dissolved oxygen content in the water. This collection includes general information, classroom activities, and data collected from hypoxia projects.

  16. PESTICIDE ROOT ZONE MODEL

    Science.gov (United States)

    PRZM3 is a modeling system that links two subordinate models - PRZM and VADOFT to predict pesticide transport and transformation down through the crop root and unsaturated zone. PRZM3 includes modeling capabilities for such phenomena as soil temperature simulation, vo...

  17. Mesoscale eddies and chimneys in the marginal ice zone

    Science.gov (United States)

    Sandven, S.; Johannessen, O. M.; Johannessen, J. A.

    1991-07-01

    A review of observation and modeling of mesoscale eddies and chimneys in the marginal ice zone is presented. Deep water formation, which is important for the global climate, occurs only in a few locations of the world ocean mainly at high latitudes. Some of these locations are associated with eddies in or near the marginal ice zone of the Arctic as well as the Antarctic. Deep water formation is not a well understood process, investigations so far indicate that it can occur intermittently in winter time in narrow chimneys of very low stability which have a horizontal extent of order 10 km and are located in the upper few hundred meters of the water column.

  18. Abundance and horizontal distribution of Lake Constance pelagic whitefish (Coregonus lavaretus L.) during winter

    OpenAIRE

    Eckmann, Reiner

    1995-01-01

    On seven dates in winter/early spring 1989/90, hydroacoustic data were sampled in the main basin of Lake Constance with a single-beam echosounder. In the pelagic zone, acoustic backscattering is almost entirely due to pelagic whitefish during that time of the year. For each sampling date, whitefish abundance was estimated for three size-classes (from -32 dB to -52 dB) and the horizontal distribution of the stock was plotted. Total population estimates for all size-classes combined agreed extr...

  19. Mutations of winter wheat induced by radionuclide contamination resulted from Chernobyl catastrophe

    International Nuclear Information System (INIS)

    It is shown that a high level of radionuclide contamination has been retained until 1992 in the zone of Chernobyl catastrophe (village Chistogalovka and the town of Pripyat).This causes the increase of the frequency of chromosome aberrations and visible mutations within the winter wheat (2.49 to 6.39 times) and (2.6 to 13.0 times), correspondingly. Chromosome aberrations and visible mutations which effect qualitative and quantitative characteristics, revealed over a long period of time, indicate that the retaining level of radionuclide contamination continues to be an efficient mutagen factor of the environment

  20. Cover cropping under temperate conditions: influence of growth period and incorporation time

    DEFF Research Database (Denmark)

    Thomsen, Ingrid Kaag; Hansen, Elly MØller

    Cover crops (CC) are generally followed by spring sown crops which limits the use of winter cereals in a crop rotation. A change from winter cereals as e.g. winter wheat (Triticum aestivum L.) to a spring sown crop as barley (Hordeum vulgare L.) often results in a reduction in grain yield. To encourage increased use of CC and to lessen the consequences on choice of main crop new innovative ways of using CC should be considered. This study tested the potential for using CC that could allow for repeated winter wheat growing and still permit CC in breaks between crops. Cruciferous CC (Raphanus sativus L., Sinapis alba L.) spread in a growing winter wheat crop in July and incorporated in September (Autumn CC) before sowing the following winter wheat was compared with the same CC cultivars sown after harvest and incorporated in spring (Winter CC). The cruciferous CC were compared with Winter CC of spring sown ryegrass (Lolium perenne L.) and a reference without CC. The study included comparable field and lysimeterexperiments where N uptake of Autumn and Winter CC were measured together with their influence on nitrate leaching. An incubation study determined the decomposability of the CC material as affected by developmental stage at incorporation and soil temperature. Cruciferous Autumn CC sown by spreading seeds in a growing winter wheat developed well provided that wheat harvest took place at normal time in mid August. Winter CC sown after harvest was likewise highly influenced by harvest time of the main crop which determined time of their sowing. The reduction in nitrate leaching with Autumn CC was generally about half of the reduction caused by Winter CC. Preliminary results suggest that the decomposability of CC is not highly affected by the developmental stage reached by the CC before incorporation.

  1. BOREAS HYD-5 Winter Surface Flux Data

    Science.gov (United States)

    Harding, Richard; Hall, Forrest G. (Editor); Huemmrich, Karl Fred (Editor); Smith, David E. (Technical Monitor)

    2000-01-01

    The BOREAS HYD-5 team collected tower flux, surface meteorological, and surface temperature data on a frozen lake (Namekus Lake) and in a mature jack pine forest in the Beartrap Creek watershed. Both sites were located in the BOREAS SSA. The objective of this study was to characterize the winter energy and water vapor fluxes, as well as related properties (such as snow density, depth, temperature, and melt) for forested and nonforested areas of the boreal forest. Data were collected on Namekus Lake in the winters of 1994 and 1996, and at Beartrap Creek in the winter of 1994 only. The data are available in tabular ASCII files. The data files are available on a CD-ROM (see document number 20010000884) or from the Oak Ridge National Laboratory (ORNL) Distributed Active Archive Center (DAAC).

  2. Assessing the mineralisation of charcoal carbon in temperate soils

    Science.gov (United States)

    Ascough, P. L.; Tilston, E.; Garnett, M.

    2012-04-01

    Charcoal is pyrolized biomass characterized by its high C content and environmental recalcitrance. Recently 'biochar' has emerged as a concept as a means of long-term C sequestration with a sequestration potential that is comparable with current global anthropogenic fossil fuel emissions (5.5-9.5 Pg C yr-1 and 5.4 Pg C yr-1, respectively). However, charcoal is not a permanent C sink and estimates of charcoal degradation rates vary from the decadal or centennial timescales, with soil residence times in the order of thousands of years. Possible mechanisms of charcoal degradation include biotically and abiotically-mediated transformation and mineralization processes, resulting in a range of products of varying recalcitrance, including CO2. In soil science the decomposition of organic matter is routinely estimated by measuring CO2 efflux, but a key obstacle for the quantification of charcoal-derived CO2 is the accurate and precise apportionment of C sources arising from slow decomposition rates. Moreover, the addition of charcoal to soil can promote decomposition of indigenous soil organic matter and the concomitant increase in CO2 production does not therefore necessarily demonstrate mineralization of the charcoal C. Radiocarbon (14C) offers significant benefits in this regard as a sensitive technique for C source apportionment. We used the 14C content of CO2 respired by a surface soil to quantify the rate of charcoal mineralization, thus demonstrating the efficacy and sensitivity of our 14C approach for estimating charcoal degradation. During incubation the variations in charcoal-derived C mineralization are consistent with the loss of more labile components in the charcoal with a maximum of 2.1% of the evolved CO2-C being attributable to mineralisation of charcoal C. Extrapolation to an annual basis suggests that the loss rate of charcoal C is <1%, supporting the view that rates of charcoal C respiration are slow in temperate woodland soil. Implications for biogeochemical cycling of charcoal C are discussed in context of previous and ongoing work in this field.

  3. Nuclear winter: The evidence and the risks

    International Nuclear Information System (INIS)

    Global concern over nuclear extinction, centered on the holocaust itself, now has turned to the more terrifying consequences of a post-war nuclear winter: ''the long-term effects - destruction of the environment, spread of epidemic diseases, contamination by radioactivity, and ... collapse of agriculture-[that] would spread famine and death to every country.'' Nuclear Winter, the latest in a series of studies by a number of different groups is clinical, analytical, systematic, and detailed. Two physicists and biologist analyze the effects on the climate, plants, animals, and living systems; the human costs; the policy implications

  4. THE DEVELOPMENT OF THE WINTER JOGGING CAP

    Directory of Open Access Journals (Sweden)

    Muhammad Qamar Khan

    2015-04-01

    Full Text Available This research project represents an E-textile, a wearable music system, which is a winter jogging cap. This cap is designed to entertain the music lovers during jogging in winters. Cap is equipped with MP3 circuit, rechargeable battery (3.7V and headphones. All circuits are embedded in knitted cap by conductive thread. This cap provides comfort to user during jogging. This project explains how all these electronic components can be embedded in a cap making it easily wearable

  5. A Suggested Thermoneutral Zone for African Lions (Panthera leo Linnaeus, 1758 in the Southwestern Kalahari, Namibia

    Directory of Open Access Journals (Sweden)

    Y. Smith

    2006-01-01

    Full Text Available Aspects of the thermoregulatory behaviour of a small pride of African lions (Panthera leo consisting of two adult males, an adult female and two cubs, were investigated at Intu Afrika Kalahari Game Reserve, southeastern Namibia, during winter 2003 and summer 2004. Early morning sunbathing on dune crests was considerably longer during winter when compared to summer, but the cutoff ambient temperature for this behaviour was the same (25°C for both seasons. Loin exposure, on both empty and full bellies, always occurred between 28 and 34°C. Panting during winter only occurred after bursts of activity on empty bellies. During summer, however, panting was observed while the pride was active and static, being initiated at ambient temperatures of 34°C. It can, therefore, be inferred that the thermoneutral zone for this pride lies between 25 and 33°C.

  6. Dynamics of soil cover state and degradation processes intensity in natural soil zones of the Altai Region

    Directory of Open Access Journals (Sweden)

    Gennady Morkovkin

    2013-07-01

    Full Text Available It is shown that the agricultural landscapes of the natural soil zones of the Altai Region are subjected to intense anthropogenic impact, and they are in an unstable state. Agricultural use has caused an extensive development of degradation processes, and the resulting indicator of those is the increase of eroded soils areas, dehumification, and the decrease of humus soil horizon thickness. More active wind erosion is revealed in the chestnut soil zone of the dry steppe and in the subzone of southern chernozems of arid steppe; a combined action of wind and water erosion is observed in the subzones of arid, temperate-arid and forest-outlier steppe, and water erosion develops in the zones of central forest-steppe and meadow steppe. The highest intensity of dehumification is observed in arid and temperate-arid steppe, and a greater change rate of soils areas in terms of humus horizon thickness decrease is observed in the chestnut soil zone of dry steppe and in the subzone of southern chernozems of arid steppe.

  7. Aridity changes in the temperate-Mediterranean transition of the Andes since ad 1346 reconstructed from tree-rings

    Energy Technology Data Exchange (ETDEWEB)

    Christie, Duncan A.; Quesne, Carlos le [Universidad Austral de Chile, Laboratorio de Dendrocronologia, Facultad de Ciencias Forestales y Recursos Naturales, Valdivia (Chile); Boninsegna, Jose A.; Morales, Mariano S.; Villalba, Ricardo [Instituto Argentino de Nivologia, Glaciologia y Ciencias Ambientales, IANIGLA, Departamento de Dendrocronologia e Historia Ambiental, Mendoza (Argentina); Cleaveland, Malcolm K.; Stahle, David W. [University of Arkansas Fayetteville, Tree-Ring Laboratory, Department of Geosciences, Fayetteville, AR (United States); Lara, Antonio [Universidad Austral de Chile, Laboratorio de Dendrocronologia, Facultad de Ciencias Forestales y Recursos Naturales, Valdivia (Chile); Universidad Austral de Chile, Forest Ecosystem Services under Climatic Fluctuations (Forecos), Valdivia (Chile); Mudelsee, Manfred [Climate Risk Analysis, Hanover (Germany); Alfred Wegener Institute for Polar and Marine Research, Bremerhaven (Germany)

    2011-04-15

    The Andes Cordillera acts as regional ''Water Towers'' for several countries and encompasses a wide range of ecosystems and climates. Several hydroclimatic changes have been described for portions of the Andes during recent years, including glacier retreat, negative precipitation trends, an elevation rise in the 0 isotherm, and changes in regional streamflow regimes. The Temperate-Mediterranean transition (TMT) zone of the Andes (35.5 -39.5 S) is particularly at risk to climate change because it is a biodiversity hotspot with heavy human population pressure on water resources. In this paper we utilize a new tree-ring network of Austrocedrus chilensis to reconstruct past variations in regional moisture in the TMT of the Andes by means of the Palmer Drought Severity Index (PDSI). The reconstruction covers the past 657 years and captures interannual to decadal scales of variability in late spring-early summer PDSI. These changes are related to the north-south oscillations in moisture conditions between the Mediterranean and Temperate climates of the Andes as a consequence of the latitudinal position of the storm tracks forced by large-scale circulation modes. Kernel estimation of occurrence rates reveals an unprecedented increment of severe and extreme drought events during the last century in the context of the previous six centuries. Moisture conditions in our study region are linked to tropical and high-latitude ocean-atmospheric forcing, with PDSI positively related to Nino-3.4 SST during spring and strongly negatively correlated with the Antarctic Oscillation (AAO) during summer. Geopotential anomaly maps at 500-hPa show that extreme dry years are tightly associated with negative height anomalies in the Ross-Amundsen Seas, in concordance with the strong negative relationship between PDSI and AAO. The twentieth century increase in extreme drought events in the TMT may not be related to ENSO but to the positive AAO trend during late-spring and summer resulting from a gradual poleward shift of the mid-latitude storm tracks. This first PDSI reconstruction for South America demonstrates the highly significant hindcast skill of A. chilensis as an aridity proxy. (orig.)

  8. Aridity changes in the Temperate-Mediterranean transition of the Andes since ad 1346 reconstructed from tree-rings

    Science.gov (United States)

    Christie, Duncan A.; Boninsegna, José A.; Cleaveland, Malcolm K.; Lara, Antonio; Le Quesne, Carlos; Morales, Mariano S.; Mudelsee, Manfred; Stahle, David W.; Villalba, Ricardo

    2011-04-01

    The Andes Cordillera acts as regional "Water Towers" for several countries and encompasses a wide range of ecosystems and climates. Several hydroclimatic changes have been described for portions of the Andes during recent years, including glacier retreat, negative precipitation trends, an elevation rise in the 0° isotherm, and changes in regional streamflow regimes. The Temperate-Mediterranean transition (TMT) zone of the Andes (35.5°-39.5°S) is particularly at risk to climate change because it is a biodiversity hotspot with heavy human population pressure on water resources. In this paper we utilize a new tree-ring network of Austrocedrus chilensis to reconstruct past variations in regional moisture in the TMT of the Andes by means of the Palmer Drought Severity Index (PDSI). The reconstruction covers the past 657 years and captures interannual to decadal scales of variability in late spring-early summer PDSI. These changes are related to the north-south oscillations in moisture conditions between the Mediterranean and Temperate climates of the Andes as a consequence of the latitudinal position of the storm tracks forced by large-scale circulation modes. Kernel estimation of occurrence rates reveals an unprecedented increment of severe and extreme drought events during the last century in the context of the previous six centuries. Moisture conditions in our study region are linked to tropical and high-latitude ocean-atmospheric forcing, with PDSI positively related to Niño-3.4 SST during spring and strongly negatively correlated with the Antarctic Oscillation (AAO) during summer. Geopotential anomaly maps at 500-hPa show that extreme dry years are tightly associated with negative height anomalies in the Ross-Amundsen Seas, in concordance with the strong negative relationship between PDSI and AAO. The twentieth century increase in extreme drought events in the TMT may not be related to ENSO but to the positive AAO trend during late-spring and summer resulting from a gradual poleward shift of the mid-latitude storm tracks. This first PDSI reconstruction for South America demonstrates the highly significant hindcast skill of A. chilensis as an aridity proxy.

  9. Reforestation with native mixed-species plantings in a temperate continental climate effectively sequesters and stabilizes carbon within decades.

    Science.gov (United States)

    Cunningham, Shaun C; Cavagnaro, Timothy R; Mac Nally, Ralph; Paul, Keryn I; Baker, Patrick J; Beringer, Jason; Thomson, James R; Thompson, Ross M

    2015-04-01

    Reforestation has large potential for mitigating climate change through carbon sequestration. Native mixed-species plantings have a higher potential to reverse biodiversity loss than do plantations of production species, but there are few data on their capacity to store carbon. A chronosequence (5-45 years) of 36 native mixed-species plantings, paired with adjacent pastures, was measured to investigate changes to stocks among C pools following reforestation of agricultural land in the medium rainfall zone (400-800 mm yr(-1)) of temperate Australia. These mixed-species plantings accumulated 3.09 ± 0.85 t C ha(-1) yr(-1) in aboveground biomass and 0.18 ± 0.05 t C ha(-1) yr(-1) in plant litter, reaching amounts comparable to those measured in remnant woodlands by 20 years and 36 years after reforestation respectively. Soil C was slower to increase, with increases seen only after 45 years, at which time stocks had not reached the amounts found in remnant woodlands. The amount of trees (tree density and basal area) was positively associated with the accumulation of carbon in aboveground biomass and litter. In contrast, changes to soil C were most strongly related to the productivity of the location (a forest productivity index and soil N content in the adjacent pasture). At 30 years, native mixed-species plantings had increased the stability of soil C stocks, with higher amounts of recalcitrant C and higher C:N ratios than their adjacent pastures. Reforestation with native mixed-species plantings did not significantly change the availability of macronutrients (N, K, Ca, Mg, P, and S) or micronutrients (Fe, B, Mn, Zn, and Cu), content of plant toxins (Al, Si), acidity, or salinity (Na, electrical conductivity) in the soil. In this medium rainfall area, native mixed-species plantings provided comparable rates of C sequestration to local production species, with the probable additional benefit of providing better quality habitat for native biota. These results demonstrate that reforestation using native mixed-species plantings is an effective alternative for carbon sequestration to standard monocultures of production species in medium rainfall areas of temperate continental climates, where they can effectively store C, convert C into stable pools and provide greater benefits for biodiversity. PMID:25230693

  10. Measuring free energy in spin-lattice models using parallel tempering Monte Carlo

    Science.gov (United States)

    Wang, Wenlong

    2015-05-01

    An efficient and simple approach of measuring the absolute free energy as a function of temperature for spin lattice models using a two-stage parallel tempering Monte Carlo and the free energy perturbation method is discussed and the results are compared with those of population annealing Monte Carlo using the three-dimensional Edwards-Anderson Ising spin glass model as benchmark tests. This approach requires little modification of regular parallel tempering Monte Carlo codes with also little overhead. Numerical results show that parallel tempering, even though using a much less number of temperatures than population annealing, can nevertheless equally efficiently measure the absolute free energy by simulating each temperature for longer times.

  11. Evaluation of temper embrittlement of martensitic and ferritic-martensitic steels by acoustic emission

    International Nuclear Information System (INIS)

    Martensitic (HT-9) and ferritic-martensitic steels (9Cr-2Mo) are considered as fusion first wall materials. In this investigation in order to understand the sensitivity of temper embrittlement in these steels under actual service condition, fracture toughness testing was made by use of acoustic emission technique. The temper embrittlement was characterized in terms of fracture toughness. The fracture toughness of these steels under 500 deg C, 100 hrs, and 1000 hrs heat treatment was decreased and their changes in micro-fracture process have been observed. The fracture toughness changes by temper embrittlement was discussed by the characteristic of AE, AE spectrum analysis and fractographic investigation. The relation between micro-fracture processes and AE has been clarified. (author)

  12. Dry sliding wear system response of ferritic and tempered martensitic ductile iron

    Science.gov (United States)

    Jha, V. K.; Mozumder, Y. H.; Shama, S.; Behera, R. K.; Pattaniak, A.; P, Sindhoora L.; Mishra, S. C.; Sen, S.

    2015-02-01

    Spheroidal graphite cast iron (SG iron) is the most preferable member of cast iron family due to its strength and toughness along with good tribological properties. SG iron specimens with annealed and martensitic matrix were subjected to dry sliding wear condition and the system response was correlated to matrix microstructure. Respective microstructure was obtained by annealing and quench and tempering heat treatment process for an austenitizing temperature of 1000°C. Specimens were subjected to Ball on plate wear tester under 40N, 50N, 60N load for a sliding distance of 7.54m. Except for quench and tempered specimen at 50N, weight loss was observed in every condition. The wear surface under optical microscope reveals adhesive mechanism for as-cast and annealed specimen whereas delaminated wear track feature was observed for quench and tempered specimen.

  13. Evolution of compressive strains in retained austenite during sub-zero Celsius martensite formation and tempering

    DEFF Research Database (Denmark)

    Villa, Matteo; Pantleon, Karen

    2014-01-01

    The development of martensite during sub-zero Celsius treatment of a 1 wt.% C, 1.6 wt.% Cr steel was investigated by in situ and ex situ (synchrotron) X-ray diffraction at the synchrotron facility HZB-BESSY II in order: (i) to quantitatively assess the fractions of retained austenite and martensite; (ii) to measure the evolution of the lattice strain in retained austenite; and (iii) to identify the different stages of tempering. This work shows for the first time that the compressive strains built up in austenite upon martensite formation during sub-zero Celsius treatment are retained after tempering. Furthermore, it is demonstrated that sub-zero Celsius treatment after tempering leads to compressive strain in austenite. Finally, it is reported that no compressive strain builds up in austenite when the martensite formation occurs below a certain critical temperature.

  14. Glasgow's temperance story: changing approaches towards the control of alcohol abuse.

    Science.gov (United States)

    Mullen, K

    1989-11-01

    This article gives an account of the growth and eventual decline of Glasgow's Temperance Movement from its beginnings in the early part of the 19th century, to the present day. The article focuses on the changing rhetoric, aims and practice of the various organisations within the Glasgow Temperance Movement. These shifts, from individual persuasion to moves for government legislation, are analysed in relation to the social and political conditions of their time. The article concludes by drawing comparisons between these early changes within the Temperance Movement and the current shifts with regard to alcohol policy, from concern for the 'alcoholic' to a more generalised focus on the 'moderate drinker', being witnessed at present in the UK. PMID:2687207

  15. CRITICAL ASSESSMENT OF THE DEGREE OF TEMPER EMBRITTLEMENT IN 2.25Cr-1Mo STEEL

    Directory of Open Access Journals (Sweden)

    M.A. Islam

    2006-06-01

    Full Text Available Reversible temper embrittlement has been frequently observed in many different low alloy steels, serving at high temperatures, due to segregation of trace elements at grain boundaries and/or carbide/matrix interfaces. This type of impurity element segregation can severely deteriorate the toughness and fatigue properties of the steel. In general, increase in the hardness and tensile strength also increases the fatigue life of the steel. So, fatigue lives of steels are sometimes assessed by these parameters. In this research work 2.25Cr-1Mo steel, before and after temper embrittlement, was characterized by microstructure observation, hardness measurement, tensile, fatigue and fracture toughness tests at room temperature in air. Experimental results revealed that temper embrittlement hardly modify the room temperature hardness values and tensile properties, although the fatigue and fracture behaviours of this steel are significantly changed.

  16. Evolution of compressive strains in retained austenite during sub-zero Celsius martensite formation and tempering

    International Nuclear Information System (INIS)

    The development of martensite during sub-zero Celsius treatment of a 1 wt.% C, 1.6 wt.% Cr steel was investigated by in situ and ex situ (synchrotron) X-ray diffraction at the synchrotron facility HZB-BESSY II in order: (i) to quantitatively assess the fractions of retained austenite and martensite; (ii) to measure the evolution of the lattice strain in retained austenite; and (iii) to identify the different stages of tempering. This work shows for the first time that the compressive strains built up in austenite upon martensite formation during sub-zero Celsius treatment are retained after tempering. Furthermore, it is demonstrated that sub-zero Celsius treatment after tempering leads to compressive strain in austenite. Finally, it is reported that no compressive strain builds up in austenite when the martensite formation occurs below a certain critical temperature

  17. Sediment CO2 efflux from cleared and intact temperate mangroves and tidal flats

    Science.gov (United States)

    Bulmer, R. H.; Schwendenmann, L.; Lundquist, C. J.

    2015-02-01

    Temperate mangroves in Southern Australia and New Zealand have been increasing in area over the past 50 years, whereas tropical mangroves have declined by 30-50% over a similar time frame. Tropical mangroves are understood to be an important carbon sink and carbon dioxide (CO2) emissions following clearance are estimated to be comparable or greater than CO2 emissions following the clearance of many terrestrial forest systems. Recreational and amenity values or perceived loss of other estuarine habitats due to expanding temperate mangrove forests have resulted in clearing of temperate mangroves. In this study, we investigated the impact of temperate mangrove clearance on CO2 efflux from the sediment to the atmosphere along with a range of other biotic and abiotic factors. Significantly higher CO2 efflux rates were measured in cleared (1.34 ± 0.46 ?mol m2 s-1) and intact mangrove sites (2.31 ± 0.72 ?mol m2 s-1) than in tidal flats (-0.23 ± 0.27 ?mol m2 s-1). Site and sediment characteristics such as sediment carbon and nitrogen concentration, chlorophyll ? concentration, grain size, mangrove height, macrofaunal abundance, sediment temperature and moisture were strongly correlated with sediment CO2 efflux. Our results suggest that carbon stored within temperate mangrove sediment is released over a period of years to decades after mangrove clearance. CO2 efflux from intact and cleared temperate mangroves was found to be comparable to rates observed in the tropics. Disturbance of the surface biofilm resulted in elevated CO2 efflux across all habitats, suggesting the important role of surface biofilm communities in mediating CO2 efflux.

  18. On the potential application of polar and temperate marine microalgae for EPA and DHA production.

    Science.gov (United States)

    Boelen, Peter; van Dijk, Roechama; Sinninghe Damsté, Jaap S; Rijpstra, W Irene C; Buma, Anita Gj

    2013-01-01

    Long chain polyunsaturated fatty acids (LC-PUFAs) such as eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) are considered essential omega-3 fatty acids in human nutrition. In marine microalgae EPA and/or DHA are allegedly involved in the regulation of membrane fluidity and thylakoid membrane functioning. The cellular content of EPA and DHA may therefore be enhanced at low temperature and irradiance conditions. As a result, polar and cold temperate marine microalgal species might potentially be suitable candidates for commercial EPA and DHA production, given their adaptation to low temperature and irradiance habitats.In the present study we investigated inter- and intraspecific EPA and DHA variability in five polar and (cold) temperate microalgae. Intraspecific EPA and DHA content did not vary significantly in an Antarctic (Chaetoceros brevis) and a temperate (Thalassiosira weissflogii) centric diatom after acclimation to a range of irradiance levels at two temperatures. Interspecific variability was investigated for two Antarctic (Chaetoceros brevis and Pyramimonas sp. (Prasinophyceae)) and three cold-temperate species (Thalassiosira weissflogii, Emiliania huxleyi (Prymnesiophyceae) and Fibrocapsa japonica (Raphidophyceae)) during exponential growth. Interspecific variability was shown to be much more important than intraspecific variability. Highest relative and absolute levels of DHA were measured in the prymnesiophyte E. huxleyi and the prasinophyte Pyramimonas sp., while levels of EPA were high in the raphidophyte F. japonica and the diatoms C. brevis and T. weissflogii. Yet, no significant differences in LC-PUFA content were found between polar and cold-temperate species. Also, EPA and DHA production rates varied strongly between species. Highest EPA production rate (174 ?g L-1 day-1) was found in the Antarctic diatom Chaetoceros brevis, while DHA production was highest in the cold-temperate prymnesiophyte Emiliania huxleyi (164 ?g L-1 day-1). We show that, following careful species selection, effective mass cultivation of marine microalgae for EPA and DHA production may be possible under low temperature and irradiance conditions. PMID:23673135

  19. Meiobenthos of the bay of saint-brieuc (north brittany, france) .1. quantitative distribution in subtidal and intertidal zones

    OpenAIRE

    Leguellec, C.; Bodin, P.

    1992-01-01

    In the eutrophicated Bay of Saint-Brieuc (western English Channel, France), density and biomass of the multicellular meiofauna were estimated in different intertidal and subtidal biotopes, in winter and late spring. Mean annual biomass varies from 0.5 to 2.3 g.m-2 in the intertidal zone, and from 0.5 to 1.1 g.m-2 in the subtidal zone. Vertical distribution (0-5 versus 5-10 cm) of taxa was considered in the intertidal zone. Results are discussed and compared to literature data: figures were si...

  20. [Workers' housing. One aspect of the temperance movement in Spain during the Restoration].

    Science.gov (United States)

    Campos Marín, R

    1994-01-01

    The Spanish Restoration saw the development of a pro-temperance literature, aimed at warning against the dangers of the excessive drinking and demanding that the authorities apply measures to decrease the consumption of alcohol. One of the basic pillars of the temperance movement was the construction of housing for workers. The possibility of workers becoming owners of a healthy, comfortable home, and internalization of the bourgeois concept of the home, were fundamental influences on strategies to keep workers away from the taverns. PMID:11624898

  1. Temper hardening in low-carbon 15Kh1NMFA and 10GN2MFA steels

    International Nuclear Information System (INIS)

    A study on the nature of secondary hardening of welded up low-carbon pearlite steels 15Kh2NMFA and 10NG2MFA has been performed following tempering, including the connection of hardening with ductile-brittle transitions. Changes in the mechanical properties of the above steels are stated to be defined by the type, shape, size and distribution pattern of carbide phases (mainly alloyed cementite). A uniform distribution of particular carbides ensures thermal stability of a solid solution, the secondary hardening following tempering resulting in a better thermal stability. Controlling the phase composition of the steels is shown to enable obtaining the optimal relationship between the strength and ductile properties

  2. Soil organic matter, biota and aggregation in temperate and tropical soils - Effects of no-tillage

    OpenAIRE

    Six, Johan; Feller, Christian (ed.); Denef, Karolien; Ogle, Stephen; Joao Carlos de Moraes Sa,; Albrecht, Alain

    2002-01-01

    The long-term stabilization of soil organic matter (SOM) in tropical and temperate regions is mediated by soil biota (e.g. fungi, bacteria, roots and earthworms), soil structure (e.g. aggregation) and their interactions. On average, soil C turnover was twice as fast in tropical compared with temperate regions, but no major differences were observed in SOM quality between the two regions. Probably due to the soil mineralogy dominated by 1:1 clay minerals and oxides in tropical regions, we foun...

  3. Structural and functional characterization of a winter malting barley

    OpenAIRE

    Muñoz-Amatriaín, María; Cistué Sola, Luis; Xiong, Y.; Bilgic, H; Budde, A D; Schmitt, M.R.; Smith, K. P.; Hayes, P.M.; Muehlbauer, G. J.

    2010-01-01

    The development of winter malting barley (Hordeum vulgare L.) varieties is emerging as a worldwide priority due to the numerous advantages of these varieties over spring types. However, the complexity of both malting quality and winter hardiness phenotypes makes simultaneous improvement a challenge. To obtain an understanding of the relationship between loci controlling winter hardiness and malt quality and to assess the potential for breeding winter malting barley varieties, we structurally ...

  4. Vadose zone water fluxmeter

    Science.gov (United States)

    Faybishenko, Boris A.

    2005-10-25

    A Vadose Zone Water Fluxmeter (WFM) or Direct Measurement WFM provides direct measurement of unsaturated water flow in the vadose zone. The fluxmeter is a cylindrical device that fits in a borehole or can be installed near the surface, or in pits, or in pile structures. The fluxmeter is primarily a combination of tensiometers and a porous element or plate in a water cell that is used for water injection or extraction under field conditions. The same water pressure measured outside and inside of the soil sheltered by the lower cylinder of the fluxmeter indicates that the water flux through the lower cylinder is similar to the water flux in the surrounding soil. The fluxmeter provides direct measurement of the water flow rate in the unsaturated soils and then determines the water flux, i.e. the water flow rate per unit area.

  5. "The Queen of the Lobby": Mary Hunt, Scientific Temperance, and the Dilemma of Democratic Education in America, 1879-1906.

    Science.gov (United States)

    Zimmerman, Jonathan

    1992-01-01

    Describes the work of Mary Hunt and the Scientific Temperance movement to mandate teaching about the nature of alcohol and narcotics in the public schools. Examines the struggle over organization and planning within the public school system. Discusses organization in the Scientific Temperance movement's response to public school administration and…

  6. The Goldilocks Zone

    Science.gov (United States)

    Tony Phillips

    This on-line news article introduces the Goldilocks Zone, an area of space adequate for the survival of life. Initially believed to be a remarkably small region of space that didn't even include the whole Earth, recent discoveries of extremophiles found thriving in unlikely habitats are convincing scientists to change their definition. Scientists Elena Pikuta and Richard Hoover are highlighted for their discovery of the new species Tindallia californiensis and Spirochaeta americana in the extreme environment of Mono Lake, California.

  7. Cohesive zone modelling.

    Czech Academy of Sciences Publication Activity Database

    Kozák, Vladislav

    New York : American Institute of Physics, 2008, s. 328-331. ISBN 978-0-7354-0576-9. ISSN 0094-243X. - (AIP Conference Proceedings. Mathematical and Statistical Physics. Vol. 1048). [International conference on numerical analysis and applied mathematics 2008. Psalidi, Kos (GR), 16.09.2008-20.09.2008] R&D Projects: GA ?R GA101/08/1304 Institutional research plan: CEZ:AV0Z20410507 Keywords : cohesive zone modelling * brittle fracture * intermetalic alloy Subject RIV: JG - Metallurgy

  8. DHTML Zone: Macromedia

    Science.gov (United States)

    The DHTML Zone is provided by Macromedia Inc., and offers an abundance of resources to help add Dynamic HTML to a website. The basics are covered in articles, tutorials, a discussion group, and DHTML demos. For those interested in incorporating DHTML and Shockwave together, there is an entire section devoted to accomplishing this. A listing of other resources which include reference guides, more articles, demos, tutorials, and information on Netscape Communicator 4.0 and Internet Explorer 4.O is also provided.

  9. Irradiation damage 'displacement zone'

    International Nuclear Information System (INIS)

    It is well known that a charged particle (ion, primary atom, etc...) moving in a solid slows down and can cause a cascade of displacements of the atoms in the solid. A study is made here of the extent to which the cascade is made up, or not, of independent collisions, as a function of the energy of the initial charged particle. When the distance between the collisions is small, these latter are no longer independent; the cascade, which then has to be considered as a whole, perturbs and locates, in the irradiated solid , a zone which has been named a 'displacement zone'. It is shown that the proportion of displacement zones increases with increasing atom size (high atomic number Z), with decreasing atomic distance D in the substance considered and with decreasing energy of the ion undergoing the slowing down process (although always remaining above a few hundred eV). The proportions obtained are higher than those corresponding to the calculations of J. A. Brinkman [3]. An interatomic potential required for this work has also been determined. (author)

  10. The uncomfortable comfort zone

    Directory of Open Access Journals (Sweden)

    Carlos Renato Zacharias

    2012-04-01

    Full Text Available Whenever we achieve the satisfaction of our expectations and anxiety dissolves, we feel as if we were in a comfort zone – safe, complete, free from risks and in peace with ourselves. We might even have a little taste of heaven when we feel that we have fulfilled our duty. And as a fact, scientists are entitled to this kind of reward… but not for too long! In science, to enter a comfort zone can be as pleasant as dangerous. On one hand we may have a safe ground available to develop new modes of reasoning, protocols and theories. And on the other, we may stay stuck in a conventional but fragile ground, missing opportunities to reveal novel secrets or to address edge issues. ... The community of HD researchers seems to have entered a new comfort zone when nanostructures were found in HD. Nanostructures have been raised to the level of ultimate evidence doing away with Avogadro’s limit and leading homeopathy and HD research into mainstream science. We really should enjoy this moment and collect more information about the HD phenomenon. However, we must be wary to not fall into a trap.

  11. BIOCHEMICAL ANALYSIS OF MULBERRY ASSOCIATED WITH INTERCROPPING OF MEDICINAL PLANTS UNDER TEMPERATE CLIMATIC CONDITIONSBIOCHEMICAL ANALYSIS OF MULBERRY ASSOCIATED WITH INTERCROPPING OF MEDICINAL PLANTS UNDER TEMPERATE CLIMATIC CONDITIONS

    OpenAIRE

    Rathore, M. S.; Srinivasulu, Y.; Kour, R.; Anil Dhar; Sahaf, K. A.

    2012-01-01

    The Kashmir valley represents temperate climatic conditions and is known for its bivoltine sericulture. The sericulture in the region however, sustains on tree type of plants. Majority of sericulturists in this traditional area have taken up mulberry cultivation on small land holdings as a life sustaining occupation. Other farmers with more land have taken up it as subsidiary occupation. Mulberry is facing stiff competition from other economic crops. In order to make the mulberry cultivation...

  12. Livable Winter Cities--Leisure Attitudes and Activities.

    Science.gov (United States)

    Neal, Larry; Coles, Roger, Ed.

    1989-01-01

    The nine articles included in this feature emphasize how leisure, recreation, health and physical activities make winter cities more livable. Specific topics include techniques for teaching about cold weather safety and cold related injuries, Arctic Winter Games, and results of a study on winter recreation in large North American communities. (IAH)

  13. Early unusual ozone loss during the Arctic winter 2002/2003 compared to other winters

    Directory of Open Access Journals (Sweden)

    F. Goutail

    2004-09-01

    Full Text Available Total column ozone reduction in the Arctic is evaluated each winter since 1993/1994 by the transport method (3-D CTM passive ozone minus measurements. The cumulative loss from 1 December to the end of the season ranges from 5–10% during warm winters like 1998/1999, 2000/2001 and 2001/2002 up to 30%–32% during cold winters like 1994/1995 and 1995/1996. The 23% cumulative loss observed during the winter 2002/2003 is similar in amplitude to the 20–24% measured in 1996/1997 and 1999/2000 but the timing is different. It started unusually early in December after the occurrence of very low temperature at all stratospheric levels between 550 K and 435 K allowing PSC formation and thus chlorine activation. The early ozone loss of 2002/2003 is well captured by current 3-D CTM models.

  14. Music Activities for Lemonade in Winter

    Science.gov (United States)

    Cardany, Audrey Berger

    2014-01-01

    "Lemonade in Winter: A Book About Two Kids Counting Money" is a children's book about math; however, when sharing it in the music classroom, street cries and clapping games emerge. Jenkins' and Karas' book provides a springboard to lessons addressing several music elements, including form, tempo, and rhythm, as well as…

  15. The Winter Room at Rosenborg Castle

    DEFF Research Database (Denmark)

    Wadum, JØrgen

    An account of the creation of the highly decorated ensemble forming the Winter Room and the Writing Room, Christian 4s private quarters at Rosenborg Castle. Art historical, technical analysis reveals new evidence on the working practice of Danish and Antwerp artists and craftsmen in the first quarter of the 17th century.

  16. DIELECTRIC SPECTROSCOPY OF HARD RED WINTER WHEAT

    Science.gov (United States)

    The dielectric properties (components of the complex permittivity relative to free space) of ground hard red winter wheat of 11 to 25 percent moisture content were determined by dielectric spectroscopy measurements with an open-ended coaxial-line probe and impedance analyzer over the frequency range...

  17. Stay Safe and Healthy This Winter!

    Centers for Disease Control (CDC) Podcasts

    2010-11-23

    In this podcast for kids, the Kidtastics offer some simple ways to stay safe and healthy during the winter holiday season.  Created: 11/23/2010 by CDC Office of Womenâ??s Health.   Date Released: 11/23/2010.

  18. Winter cooling in the northern Arabian Sea

    Digital Repository Service at National Institute of Oceanography (India)

    PrasannaKumar, S.; Prasad, T.G.

    1996-01-01

    forcing that leads to the observed high productivity during winter in the northern Arabian Sea. The weak northerly winds and increased solar insolation during the inter-monsoon period, led to the development of a highly stratified upper layer with warm sea...

  19. Appalachia's Winter Secret: Downhill on the Mountains.

    Science.gov (United States)

    Johnson, Randy

    1991-01-01

    Describes ski-industry and winter-tourism growth in Appalachia. Sketches ski-resort developments in Maryland, Pennsylvania, North Carolina, and West Virginia. Describes economic threats to industry, its economic impact on Appalachian states and region, resorts' general qualities, and ski industry's promotional efforts. (TES)

  20. IMPACT OF OZONE ON WINTER WHEAT YIELD

    Science.gov (United States)

    Wheat is one of the more important agricultural crops in the USA, and the major production areas may be subjected to potentially damaging concentrations of ozone (O3). Since no information was available regarding the O3 sensitivity of winter wheat cultivars grown in the Midwest, ...

  1. Global Distribution of Aerosols Over the Open Ocean as Derived from the Coastal Zone Color Scanner

    Science.gov (United States)

    Stegmann, P. M.; Tindale, N. W.

    1999-01-01

    Climatological maps of monthly mean aerosol radiance levels derived from the coastal zone color scanner (CZCS) were constructed for the world's ocean basins. This is the first study to use the 7.5.-year CZCS data set to examine the distribution and seasonality of aerosols over the open ocean on a global scale. Examination of our satellite images found the most prominent large-scale patch of elevated aerosol radiances in each month off the coast of northwest Africa. The well-known, large-scale plumes of elevated aerosol levels in the Arabian Sea, the northwest Pacific, and off the east coast of North America were also successfully captured. Radiance data were extracted from 13 major open-ocean zones, ranging from the subpolar to equatorial regions. Results from these extractions revealed the aerosol load in both subpolar and subtropical zones to be higher in the Northern Hemisphere than in the Southern Hemisphere. Aerosol radiances in the subtropics of both hemispheres were about 2 times higher in summer than in winter. In subpolar regions, aerosol radiances in late spring/early summer were almost 3 times that observed in winter. In general, the aerosol signal was higher during the warmer months and lower during the cooler months, irrespective of location. A comparison between our mean monthly aerosol radiance maps with mean monthly chlorophyll maps (also from CZCS) showed similar seasonality between aerosol and chlorophyll levels in the subpolar zones of both hemispheres, i.e., high levels in summer, low levels in winter. In the subtropics of both hemispheres, however, chlorophyll levels were higher in winter months which coincided with a depressed aerosol signal. Our results indicate that the near-IR channel on ocean color sensors can be used to successfully capture well-known, large-scale aerosol plumes on a global scale and that future ocean color sensors may provide a platform for long-term synoptic studies of combined aerosol-phytoplankton productivity interactions.

  2. Winter Refuge for Aedes aegypti and Ae. albopictus Mosquitoes in Hanoi during Winter

    OpenAIRE

    Tsunoda, Takashi; Cuong, Tran Chi; Dong, Tran Duc; Yen, Nguyen Thi; Le, Nguyen Hoang; Phong, Tran Vu; Minakawa, Noboru

    2014-01-01

    Dengue occurs throughout the year in Hanoi, Vietnam, despite winter low temperatures 14°C, exceeding the developmental zero point of Ae. aegypti. Although jars, drums and concrete tanks were the dominant containers previously (1994–97) in Hanoi, currently the percentage of residences with concrete tanks was still high while jars and drums were quite low. Our study showed that concrete tanks with broken lids allowing mosquitoes access were important winter refuge for Ae. aegypti. We also in...

  3. ECONOMIC EFFICIENCY OF THE WINTER WHEAT (TRITICUM AESTIVUM L.) AND WINTER SPELT (TRITICUM SPELTA L.) GROWING IN ORGANIC FARMING

    OpenAIRE

    J. ŠRÁMEK; P. Konvalina; I. ZDRHOVÁ; J. MOUDRÝ jr.; J. MOUDRÝ

    2009-01-01

    Comparison of economic efectivity of the winter wheat (Triticum aestivum L.) and winter spelt (Triticum spelta L.) growing in organic farming systems. The differences of yield of two species wheats in organic farming system and factors are evaluated. In relation to standart technological procedures in farming systems are defined costs for area nad for production unit. Structure of costs on production, price differences between the winter wheat and winter spelt are analysed.

  4. Positive feedback of elevated CO2 on soil respiration in late autumn and winter

    Science.gov (United States)

    Keidel, L.; Kammann, C.; Grünhage, L.; Moser, G.; Müller, C.

    2015-02-01

    Soil respiration of terrestrial ecosystems, a major component in the global carbon cycle is affected by elevated atmospheric CO2 concentrations. However, seasonal differences of feedback effects of elevated CO2 have rarely been studied. At the Gießen Free-Air CO2 Enrichment (GiFACE) site, the effects of +20% above ambient CO2 concentration have been investigated since 1998 in a temperate grassland ecosystem. We defined five distinct annual seasons, with respect to management practices and phenological cycles. For a period of 3 years (2008-2010), weekly measurements of soil respiration were carried out with a survey chamber on vegetation-free subplots. The results revealed a pronounced and repeated increase of soil respiration under elevated CO2 during late autumn and winter dormancy. Increased CO2 losses during the autumn season (September-October) were 15.7% higher and during the winter season (November-March) were 17.4% higher compared to respiration from ambient CO2 plots. However, during spring time and summer, which are characterized by strong above- and below-ground plant growth, no significant change in soil respiration was observed at the GiFACE site under elevated CO2. This suggests (1) that soil respiration measurements, carried out only during the growing season under elevated CO2 may underestimate the true soil-respiratory CO2 loss (i.e. overestimate the C sequestered), and (2) that additional C assimilated by plants during the growing season and transferred below-ground will quickly be lost via enhanced heterotrophic respiration outside the main growing season.

  5. Nitrogen Deposition Effects on Soil Carbon Dynamics in Temperate Forests

    DEFF Research Database (Denmark)

    Ginzburg Ozeri, Shimon

    2014-01-01

    Soils contain the largest fraction of terrestrial carbon (C). Understanding the factors regulating the decomposition and storage of soil organic matter (SOM) is essential for predictions of the C sink strength of the terrestrial environment in the light of global change. Elevated long-term nitrogen (N) deposition into forest ecosystems has been increasing globally and was hypothesized to raise soil organic C (SOC) stocks by increasing forest productivity and by reducing SOM decomposition. Yet, these effects of N deposition on forest SOC stocks are uncertain and largely based on observations from high dose-N fertilization experiments. Here, I present a synthesis of results from three studies aiming at elucidating the effects of long-term N deposition on SOC stocks and fluxes in temperate conifer forests. In two of the studies, short N deposition gradients occurring naturally in forest edges were used to study the effects of varying N deposition load on SOC stocks and fluxes as well as on the temperature sensitivity of SOM respiration. In a third study, the effects of 20 years of continuous experimental N addition (35 kg N ha-1 year-1) on soil C budget were investigated. Our general hypotheses were that elevated N deposition will: i) increase SOC stocks owing to positive effect of N on litterfall C inputs combined with negative effect on SOM decomposition regardless of negative effects on belowground C inputs by roots and associated mycorrhiza; ii) reduce the temperature sensitivity of SOM heterotrophic respiration. The five forest edges investigated exhibited N deposition gradients decreasing from the edges toward the interior of the stands. Thus, increasing distance from the edge was used as proxy for decreasing N deposition. At the two edges receiving intermediate-N deposition rates (? 23 kg N ha-1 year-1), forest floor SOC stocks tended to decrease with distance from the edge while a decade of experimental N additions insignificantly increased the size of the humus (H) layer providing weak evidence for somepositive effect of N deposition on SOC stocks. The three edges receiving higher N deposition rates (> 29 kg N ha-1 year-1) were N-saturated where SOC stocks in the top soil were either unchanged or negatively affected by elevated N deposition. Similarly, forest floor SOC stocks were unchanged following two decades of experimental-N additions. Aboveground C inputs by needle litterfall were generally not significantly affected by N deposition at the edge sites but tended to increase with increasing distance from the edge in two of the N-saturated sites. The experimental N additions resulted in reduced C inputs by foliar litter relative to control concomitant with reduced tree and moss growth. At three edges, fine-root biomass tended to increase with distance from the edge while over a decade of N additions reduced the means of fine-root biomass, ectomycorrihizal (EM) mycelial production and species composition insignificantly compared with control suggesting reduced belowground C inputs under elevated N deposition. At two edge sites, forest floor C outputs by respiration tended to decrease with decreased forest floor C/N and distance from the edge indicating positive effect of elevated N deposition on SOC sequestration. Correspondingly, N-enriched litter incubated in litterbags had significantly lower late-stage decomposition rates compared with control litter. However, potential respiration of forest floor and mineral soil was overall unaffected by the experimental N-additions. A temperature treatment of forest floor samples taken from one edge site revealed decreasing respiration rates and temperature sensitivity (Q10) of labile and recalcitrant SOM with increasing forest floor C/N ratio. I conclude that N deposition at rates typical to agriculturally intensified regions in north-western Europe may reduce the decomposition rate of SOM thereby positively affecting SOC sequestration but at the same time above- and belowground C inputs also decrease resulting in no change in SOM stocks. Moreover, elevated N deposition

  6. Nuclear Winter: The implications for civil defense

    International Nuclear Information System (INIS)

    ''Nuclear Winter'' is the term given to hypothesized cooling in the northern hemisphere following a nuclear war due to injection of smoke from burning cities into the atmosphere. The voluminous literature on this subject produced since the original paper in 1983 by Turco, Toon, Ackerman, Pollack, and Sagen (TTAPS) has been reviewed. The widespread use of 3-dimensional global circulation models have resulted in reduced estimates of cooling; 15 to 250C for a summer war and a few degrees for a winter war. More serious may be the possibility of suppression of convective precipitation by the altered temperature profiles in the atmosphere. However, very large uncertainties remain in input parameters, the models, and the results of calculations. We believe the state of knowledge about nuclear winter is sufficiently developed to conclude: Neither cold nor drought are likely to be direct threats to human survival for populations with the wherewithal to survive normal January temperatures; The principal threat from nuclear winter is to food production, and could present problems to third parties without food reserves; and Loss of a crop year is neither a new nor unexpected threat from nuclear war to the US and the Soviet Union. Both have at least a year's food reserve at all times. Both face formidable organizational problems in distributing their reserves in a war-damaged environment. The consequences of nuclear winter could be expected to fall more heavily on the Soviet Union than the US due to its higher latitude and less productive agriculture. This may be especially true if disturbances of rainfall amounts and distribution persist for more than a year. 6 refs

  7. Effects of boundary characteristics on resistance to temper embrittlement and segregation behavior of Ni-Cr-Mo low alloy steel

    Energy Technology Data Exchange (ETDEWEB)

    Park, Sang-Gyu; Lee, Ki-Hyoung [Nuclear Materials Research Division, Korea Atomic Energy Research Institute, Daedeok-daero 989-111, Yuseong-gu, Daejeon 305-353 (Korea, Republic of); Kim, Min-Chul, E-mail: mckim@kaeri.re.kr [Nuclear Materials Research Division, Korea Atomic Energy Research Institute, Daedeok-daero 989-111, Yuseong-gu, Daejeon 305-353 (Korea, Republic of); Lee, Bong-Sang [Nuclear Materials Research Division, Korea Atomic Energy Research Institute, Daedeok-daero 989-111, Yuseong-gu, Daejeon 305-353 (Korea, Republic of)

    2013-01-20

    SA508 Gr.4N Ni-Cr-Mo low alloy steel has higher strength and fracture toughness than those of commercial SA508 Gr.3 low alloy steel, due to its tempered martensitic microstructure as well as the solid solution effect and its higher contents of Ni and Cr. Hence, several studies have been performed on SA508 Gr.4N for nuclear application. In this study, the effects of microstructure on temper embrittlement and segregation behaviors in Ni-Cr-Mo low alloy steel were evaluated from the viewpoint of grain boundary characteristics. To evaluate the microstructural effect while excluding chemistry effects, the same heat was used but different microstructure samples were prepared by changing the cooling rate after austenitization. The increased volume fraction of martensite reduces the resistance to temper embrittlement, showing an increased transition-temperature shift (TTS) and increased P segregation at prior austenite boundaries. The segregation occurred intensively at prior austenite grain boundaries in tempered martensite, while the segregation occurred simultaneously at both prior austenite boundaries and packet boundaries in tempered bainite. In the EBSD results, most of the packet boundaries in tempered martensite are special boundaries such as N-Ary-Summation 3 coincident site lattice (CSL) boundaries. The differences in P segregation between tempered martensite and tempered bainite are mainly caused by different portions of low energy special boundaries among the sub-grain boundaries. The reduction of temper embrittlement resistance in tempered martensite could be explained by the increased fraction of low energy CSL boundaries, which leads to a concentrated segregation of P at prior austenite grain boundaries.

  8. Effects of boundary characteristics on resistance to temper embrittlement and segregation behavior of Ni–Cr–Mo low alloy steel

    International Nuclear Information System (INIS)

    SA508 Gr.4N Ni–Cr–Mo low alloy steel has higher strength and fracture toughness than those of commercial SA508 Gr.3 low alloy steel, due to its tempered martensitic microstructure as well as the solid solution effect and its higher contents of Ni and Cr. Hence, several studies have been performed on SA508 Gr.4N for nuclear application. In this study, the effects of microstructure on temper embrittlement and segregation behaviors in Ni–Cr–Mo low alloy steel were evaluated from the viewpoint of grain boundary characteristics. To evaluate the microstructural effect while excluding chemistry effects, the same heat was used but different microstructure samples were prepared by changing the cooling rate after austenitization. The increased volume fraction of martensite reduces the resistance to temper embrittlement, showing an increased transition-temperature shift (TTS) and increased P segregation at prior austenite boundaries. The segregation occurred intensively at prior austenite grain boundaries in tempered martensite, while the segregation occurred simultaneously at both prior austenite boundaries and packet boundaries in tempered bainite. In the EBSD results, most of the packet boundaries in tempered martensite are special boundaries such as ?3 coincident site lattice (CSL) boundaries. The differences in P segregation between tempered martensite and tempered bainite are mainly caused by different portions of low energy special boundaries among the sub-grainl boundaries among the sub-grain boundaries. The reduction of temper embrittlement resistance in tempered martensite could be explained by the increased fraction of low energy CSL boundaries, which leads to a concentrated segregation of P at prior austenite grain boundaries.

  9. Effects of cold winters and regime shifts on macrofauna communities in shallow coastal regions

    Science.gov (United States)

    Kröncke, Ingrid; Reiss, Henning; Dippner, Joachim W.

    2013-03-01

    Several ecosystem components in the North Sea have undergone fundamental changes following climatic change and this paper aims to establish if these changes also have affected macrofauna communities in the southern North Sea. From 1978 to 2005, the macrofauna communities were sampled seasonally in the sublittoral zone off the island of Norderney, one of the East Frisian barrier islands. Abundance, biomass and species numbers of single species or larger taxonomic groups showed differences in long-term variability and eurytherm species dominated in the study area. After the cold winter of 1978/79 until the mid 1980s a higher percentage of arctic-boreal species were found, while after 1988 the percentage of species with a southern distribution in the North Sea increased in connection with a smooth biological regime shift and a positive North Atlantic Oscillation (NAO) index. Interface-feeders dominated the communities, followed by sand lickers and subsurface deposit-feeders. The latter were more abundant after cold winters, probably due to their ability to utilise dead buried faunal organic matter. Multivariate analyses revealed that cold winters affected the community structure more briefly, while a smooth biological regime shift in 1989/1990 and a climate regime shift induced abrupt biological regime shift in 2001/2002 caused longer-term progressive change in the macrofauna community structure. The significant correlation between macrofauna abundance, biomass and species number and the NAO index failed until 2001 due to a change in climate systems over the northern Atlantic hemisphere.

  10. Toughness of simulated heat-affected zone microstructures in HT-9 (ESR melt practice)

    International Nuclear Information System (INIS)

    The toughness behavior of the heat-affected zone in the ESR National Fusion Heat was determined using Gleeble-simulated microstructures. Two regions of the HAZ were evaluated; one region represents the portion of the HAZ nearest the fusion zone, the other corresponds to a region which is heated only slightly above the upper critical temperature. Charpy V-notch results indicated that following a PWHT at 7600C for 1 hour both regions of the HAZ exhibit superior toughness behavior to that of the quench-and-tempered base material. The upper shelf toughness increased 20 to 40 Joules and the DBTT decreased nearly 200C relative to the base metal. The toughness of both the ESR base material and HAZ microstructures was superior to that of the AOD-processed National Fusion Heat, which had been previously tested in a similar manner

  11. Historical Consumption of Heating Natural Gas and Thermal Monitoring of a Multifamily High-Rise Building in a Temperate/Cold Climate in Argentina

    Directory of Open Access Journals (Sweden)

    Celina Filippín

    2012-12-01

    Full Text Available This paper analyzes the historical consumption of natural gas in a multifamily high-rise building and the monitored winter thermal behavior of an apartment sample. The building is located in the center of Argentina (latitude: 36º27’S; longitude: 64º27’W, where the climate is a cold temperate with an absolute minimum temperature that may reach ?10 °C. The building has two blocks, North and South. The building’s annual gas consumption and its variability between 1996 and 2008 are shown. The South block consumed 78% more gas, a situation expected due to lower solar resource availability and greater vulnerability regarding strong and cold SW winds. Indoor temperatures monitored during 2009 in four apartments are described. The outdoor minimum temperature reached ?5 °C, with solar irradiance around 500 W/m2 at midday. Results showed that the average indoor temperatures were 20.1, 20.6, 24.0 and 22.1 °C. The highest consumption value corresponded to the apartment exposed to SW cold winds. Compared to the rest of the building, the apartment on the top floor consumes 59% more energy than the average for the gas consumed throughout the year. The authors assume that the energy potentials of intervention are different, and not necessarily all the apartments should have the same technological response.

  12. The importance of groundwater discharge for plant species number in riparian zones.

    Science.gov (United States)

    Jansson, Roland; Laudon, Hjalmar; Johansson, Eva; Augspurger, Clemens

    2007-01-01

    Riparian zones are hotspots of plant species richness in temperate and boreal biomes. The phenomenon is believed to be caused primarily by river-related processes, and upland influences on riparian zones have received relatively little attention. We investigated the importance of discharge of groundwater derived from uplands on riparian patterns in vascular plant species composition. We found that groundwater discharge areas in riparian zones were 36-209% more species rich than non-discharge areas, depending on spatial scale (1-50 m wide transects from annual high-water levels to summer low-water levels) and river (one free-flowing and one regulated). Higher nitrogen availability and less drought stress during low river stages are suggested as the major causes for the higher species diversity in discharge areas. Riparian zones lacking groundwater discharge lost more species following water-level regulation than did discharge areas. This indicates that groundwater discharge areas are more resistant to regulation because both individual plants and plant populations may grow larger in discharge areas. These results demonstrate that riparian zones are controlled by water and nutrient input from upland parts of catchments in ways that have been overlooked despite more than three decades of research into linkages between stream ecosystems and their valleys. PMID:17489461

  13. Observation of Current and Leader Development Characteristics of Winter Lightning

    Science.gov (United States)

    Miki, Megumu

    Current and leader development characteristics of winter lightning occurring in the coastal area of the Sea of Japan are reviewed. The characteristics of winter lightning are different from those of usual lightning that occurs mainly in summer. The occurrence of upward flashes, the percentage of current polarities, and the median values of current peaks in winter lightning are summarized. Typical current waveforms and the corresponding leader developments of winter lightning observed at the chimney of the Fukui thermal plant are shown. We examined the parameters (peak, duration, charge transfer, action integral) of the current waveforms of winter lightning.

  14. The annual invasive plant, Impatiens glandulifera (Himalayan Balsam) as a trigger for high-magnitude soil erosion in temperate river systems

    Science.gov (United States)

    Greenwood, Philip; Kuhn, Nikolaus

    2015-04-01

    The invasive plant, Impatiens glandulifera (common English name: Himalayan Balsam), is now found in most temperate European countries, as well as across large parts of North America and on some Australasian islands. As a ruderal species, it favours damp, fertile soils that experience frequent disturbance. Riverbanks and the riparian zone thus represent prime habitat. Its ability to out-compete most perennial vegetation yet tendency to suddenly die during seasonally cold weather has led to claims that it may promote soil erosion, particularly along inland watercourses. Despite the strong implication, this was only recently proven during an investigation conducted over one dieback and regrowth cycle in 2012/13 along a watercourse in northwest Switzerland. Here we reinterpret those initial findings and also present additional data from the same watercourse which now covers three die-off and regrowth cycles, as well as data over two die-off and regrowth cycles from a river system in southwest UK. Results from all monitoring campaigns strongly support the original conclusion that I. glandulifera promotes significant soil erosion along contaminated sections of riverbank and riparian zone. More specifically, however, approximately one third of the total number of contaminated locations monitored (n=41) recorded net ground surface retreat that exceeded, by at least one order of magnitude, equivalent annual erosion rates documented on cultivated hillslopes in temperate regions. Not only does I. glandulifera induce repeat cycles of colonization and die-off, therefore, but collectively, the results generated so far strongly infer that under certain circumstances, this cycle of events can commonly trigger severe or even extreme erosion. Seasonally induced soil loss of this magnitude, particularly along short sections of watercourses, is unsustainable in the long-term and may lead to key fluvial features undergoing profound morphological and structural changes. Such an effect could reduce the stability, and hence the ability, of riverbanks to offer natural, sustainable flood protection, as well as hamper the capacity of riparian zones to buffer and retain sediment and contaminants during their passage from terrestrial to aquatic environments. Aside from the deleterious effect of large amounts of fine-sediment entering receiving watercourses, a failure of those key geomorphic components to fulfil those fundamental ecosystem services could lead to an eventual breakdown in the hydrogeomorphic functioning of whole river systems. This could make the delivery of effective sediment reduction strategies extremely challenging in the future.

  15. The kinetics of phase transformations during tempering in high-speed steels

    Directory of Open Access Journals (Sweden)

    P. Ba?a

    2007-08-01

    Full Text Available Purpose: This work contains a detailed description of the kinetics of phase transformations during continuous heating from quenched state of HS18-0-1 and HS6-5-2 high-speed steels.Design/methodology/approach: The kinetics of phase transformations during continuous heating (tempering from as-quenched state of investigated steel, was elaborated using a DT 1000 dilatometer of a French company Adamel.Findings: During heating of previously quenched HS18-0-1 and HS6-5-2 steel samples, the presence of four basic transformations was found, i.e. precipitation of ? carbide, precipitation of M3C, transformation of retained austenite and precipitation of alloy carbides of MC and M2C type. It was shown that in quenched high-speed steels a part of retained austenite transforms already during heating for tempering, but its significant part transforms only during cooling process after tempering.Research limitations/implications: The substitution of tungsten with molybdenum in HS6-5-2 steel has influenced mainly the stability of retained austenite and the temperature of precipitation beginning of MC (MCs type carbides.Practical implications: This results will be used to design new technologies of tempering of these steels.Originality/value: Characterization of kinetics phase transformations during continuous heating from quenched state in high-speed steels.

  16. Experimental Studies on Bulk Tempering of 34CrNiMo6 Steel

    International Nuclear Information System (INIS)

    The class of steels for hardening and tempering, alloyed with chrome, nickel and molybdenum, standardized in Europe (four steel grades), USA (10 grades) and Russia (9 grades) is highly diversified and is especially interesting in the production of machine parts having an extremely large range of dimensions. The heat treatment features of these steels are particularly attractive: high bainitic harden ability and a good temperability etc. The correlation between the hardness achieved after high tempering on products made from these steels, their equivalent diameter and the heat and time parameters of tempering can be explained by means or Jominy samples test for products with equivalent diameters equal to or less than 100 mm, or by the results obtained through the method of simulation of oil cooling (Pavaras-Gheller method) for products with equivalent diameters higher than 100 mm. In this paper, based on experimental results, these correlations are customized for a steel group representative as is 34CrNiMo6. (authors)

  17. The causes of local hardness increasing in power plant rotors and its modification by tempering

    International Nuclear Information System (INIS)

    Local hardness increasing on the surface of the power plant rotor may result in severe damages. One major solution for rapid repairing of the rotors is the adaptive tempering heat treatment. For this purpose, after identification of the damaged rotor, initial investigations and tests (such as visual inspection, chemical analysis, nondestructive hardness measurements and replica or on-site metallographic tests) were performed on the rotor journal. The results showed that, the occurrence of local phase transformation (i.e. tempered bainite to austenite and finally martensite) is the main factor. Finally, based on the aforementioned results, tempering heat treatment method was selected as a modifying solution for the following purposes: 1. Decreasing hardness in embrittled places (i.e. 400-690 HV) and, 2. invariable or admissible decrease of hardness in undamaged areas (250-300 HV). Experiments showed that by choosing the 680degC/4 hours as an optimum condition for tempering heat treatment, the two mentioned objectives can be met

  18. CSM Temper Mill System Identification and Modeling of Mobarake Steel Complex

    OpenAIRE

    Ehsan Tahmasebi; ?Arash Daghighi; Mohsen Ashourian?

    2008-01-01

    System identification is defined as modeling a system, using the input-output data. In this paper, CSM temper mill line was studied and parametric system identification was explained. Using ARX method, the experimental system was modeled and identified. Good agreement was obtained when comparing extracted model outputs with the experimental data.

  19. Well-temperate phage: optimal bet-hedging against local environmental collapses

    Science.gov (United States)

    Maslov, Sergei; Sneppen, Kim

    2015-01-01

    Upon infection of their bacterial hosts temperate phages must chose between lysogenic and lytic developmental strategies. Here we apply the game-theoretic bet-hedging strategy introduced by Kelly to derive the optimal lysogenic fraction of the total population of phages as a function of frequency and intensity of environmental downturns affecting the lytic subpopulation. “Well-temperate” phage from our title is characterized by the best long-term population growth rate. We show that it is realized when the lysogenization frequency is approximately equal to the probability of lytic population collapse. We further predict the existence of sharp boundaries in system’s environmental, ecological, and biophysical parameters separating the regions where this temperate strategy is optimal from those dominated by purely virulent or dormant (purely lysogenic) strategies. We show that the virulent strategy works best for phages with large diversity of hosts, and access to multiple independent environments reachable by diffusion. Conversely, progressively more temperate or even dormant strategies are favored in the environments, that are subject to frequent and severe temporal downturns. PMID:26035282

  20. On the Nature of Internal Interfaces in Tempered Martensite Ferritic Steels.

    Czech Academy of Sciences Publication Activity Database

    Dronhofer, A.; Peši?ka, J.; Dlouhý, Antonín; Eggeler, G.

    2003-01-01

    Ro?. 94, ?. 5 (2003), s. 511-520. ISSN 0044-3093 R&D Projects: GA ?R GA106/99/1172 Institutional research plan: CEZ:AV0Z2041904 Keywords : Tempered martensite ferritic steels * martensite variants * orientation imaging Subject RIV: JG - Metallurgy Impact factor: 0.637, year: 2003