WorldWideScience
 
 
1

Experimental support for food limitation of a short-distance migratory bird wintering in the temperate zone.  

Science.gov (United States)

The Winter Food Limitation Hypothesis (WFLH) states that winter food abundance is a dominant source of population limitation of migratory birds. Evidence is accumulating that long-distance migratory birds wintering in tropical climates have high overwinter survival probabilities and that winter food limitation mainly affects their fitness nonlethally by limiting energetic reserves necessary for successful reproduction. In contrast, the relative roles of direct mortality vs. indirect effects caused by food limitation have not been investigated thoroughly on short-distance migratory birds wintering in temperate zones, where they face thermal challenges. We performed the first test of the WFLH for a temperate migratory bird in the wild on the Swamp Sparrow (Melospiza georgiana), with a replicated plot-wide food supplementation experiment. In contrast to tropical, but consistent with other temperate-wintering migrants, Swamp Sparrows on unmanipulated plots showed relatively low apparent survival across the winter. Following food addition, birds (1) immigrated to experimental plots, which subsequently supported approximately 50% higher abundances, (2) experienced increases of within-season apparent survival of 8-10%, depending on age/sex class, and (3) had higher-scaled mass index values, all supporting winter food limitation. The last two findings are interrelated because birds with higher scaled mass had higher survival probabilities, further supporting direct effects of winter food limitation. Food limitation of fat reserves might also have indirect effects on reproductive success by limiting migration timing and survival during migration. Increases in scaled mass were higher in females, suggesting that they are disproportionately affected by food limitation, possibly through competition. Based on Robust Design Modeling, we found no support for emigration prior to food addition, indicating that our estimates of mortality are unbiased. PMID:24597226

Danner, Raymond M; Greenberg, Russell S; Danner, Julie E; Kirkpatrick, Laila T; Walters, Jeffrey R

2013-12-01

2

Soil Litter: Temperate Zones  

Science.gov (United States)

This two-minute radio program focuses on why temperate soils harbor more biodiversity than do tropical soils. The guest on the program, a soil biologist, explains that cooler temperatures and large-scale disturbances have promoted the evolution of more soil-dwelling species in temperate areas. The program, part of the Pulse of the Planet radio show, is available here in text and audio formats. Copyright 2005 Eisenhower National Clearinghouse

Planet, Pulse O.

2006-06-23

3

Temperate Oceans : Light Zones  

Science.gov (United States)

This reference provides an overview of the three zones into which the ocean can be divided based on the amount of light recieved: the sunlit (or euphotic) zone, the twilight (or disphotic) zone, and the midnight (or aphotic) zone. The descriptions are accompanied by diagrams and a brief listing of the organisms that live in each zone.

2007-12-12

4

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 in Dalat, Vietnam since 1986 has revealed distinct peaks of caesium isotope concentrations in air and fallout during December-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 anti cyclones, frequently observed in the most active winter monsoon period. 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 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

5

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

Digital Repository Infrastructure Vision for European Research (DRIVER)

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 upla...

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

2014-01-01

6

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

Science.gov (United States)

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.

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

2014-06-01

7

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

Directory of Open Access Journals (Sweden)

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.

J. Schuerings

2014-06-01

8

Temperate zone fens of the glaciated Midwestern USA  

Science.gov (United States)

A study of more than 70 fens in the Midwestern United States and a review of the literature indicates that these temperate zone wetlands may differ from fens of the boreal zone and are not adequately differentiated from them by present classification systems. Fens of the Midwestern temperate zone 1) are wetlands with high botanical diversity, 2) are supported in part by ground water with conductivity > 100mS/ cm and circumneutral pH, 3) contain water in the root zone during most of the growing season yet are not usually inundated, and 4) accumulate organic and/or carbonate substrates. Individually, none of these descriptors is adequate to distinguish fens from other wetland communities of the Midwest such as marshes, sedge meadows, and wet prairies; yet, when they are taken together, such discrimination is possible. While fens of this zone share many species, our study does not support using indicator species because too few are both faithfully represented and geographically widespread. Midwestern temperate fens are sustained by forces of climate, landscape, and geology, which permit ground water to seep continuously into the root zone in a focused location. Since water availability in the temperate Midwest is less than in the boreal zone, continuous discharge is needed to maintain the saturation conducive to peat formation. ?? 2002, The Society of Wetland Scientists.

Amon, J.P.; Thompson, C.A.; Carpenter, Q.J.; Miner, J.

2002-01-01

9

Winter to Spring Variations of Chromophoric Dissolved Organic Matter in a temperate estuary (Po River, Northern Adriatic Sea)  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Abstract The light absorbing fraction of dissolved organic carbon (DOC), known as chromophoric dissolved organic matter (CDOM) showed wide seasonal variations in the temperate estuarine zone in front of the Po River mouth. DOC concentrations increased from winter through spring mainly as a seasonal response to increasing phytoplankton production and thermohaline stratification. The monthly dependence of the CDOM light absorption by salinity and chlorophyll a concentrations was expl...

Berto, D.; Giani, M.; Savelli, F.; Centanni, E.; Ferrari, C. R.; Pavoni, B.

2010-01-01

10

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

DEFF Research Database (Denmark)

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.

Petersen, Eskild; Severini, Carlo

2013-01-01

11

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

Science.gov (United States)

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.

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

2014-12-01

12

Controls on winter ecosystem respiration in temperate and boreal ecosystems  

Digital Repository Infrastructure Vision for European Research (DRIVER)

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 under...

Wang, T.; Ciais, P.; Piao, S. L.; Ottle?, C.; Brender, P.; Maignan, F.; Arain, A.; Cescatti, A.; Gianelle, D.; Gough, C.; Gu, L.; Lafleur, P.; Laurila, T.; Marcolla, B.; Margolis, H.

2011-01-01

13

Larval fish dynamics in the Nxaxo-Ngqusi Estuary Complex in the warm temperate–subtropical transition zone of South Africa  

Digital Repository Infrastructure Vision for European Research (DRIVER)

The larval fish assemblage was investigated in the permanently open Nxaxo-Ngqusi Estuary Complex, situated in the subtropical–warm temperate biogeographic boundary zone of South Africa. Larval and early juvenile fishes were collected in summer and winter of 2007 and 2008 using a mixed method approach by boat-based plankton tows in mid-channel wat...

Wooldridge, T. H.; Strydom, N. A.; Wasserman, R. J.

2011-01-01

14

Controls on winter ecosystem respiration in temperate and boreal ecosystems  

Science.gov (United States)

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.

Wang, T.; Ciais, P.; Piao, S. L.; Ottlé, C.; Brender, P.; Maignan, F.; Arain, A.; Cescatti, A.; Gianelle, D.; Gough, C.; Gu, L.; Lafleur, P.; Laurila, T.; Marcolla, B.; Margolis, H.; Montagnani, L.; Moors, E.; Saigusa, N.; Vesala, T.; Wohlfahrt, G.; Koven, C.; Black, A.; Dellwik, E.; Don, A.; Hollinger, D.; Knohl, A.; Monson, R.; Munger, J.; Suyker, A.; Varlagin, A.; Verma, S.

2011-07-01

15

Controls on winter ecosystem respiration in temperate and boreal ecosystems  

Directory of Open Access Journals (Sweden)

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.

T. Wang

2011-07-01

16

Winter to spring variations of chromophoric dissolved organic matter in a temperate estuary (Po River, northern Adriatic Sea).  

Science.gov (United States)

The light absorbing fraction of dissolved organic carbon (DOC), known as chromophoric dissolved organic matter (CDOM) showed wide seasonal variations in the temperate estuarine zone in front of the Po River mouth. DOC concentrations increased from winter through spring mainly as a seasonal response to increasing phytoplankton production and thermohaline stratification. The monthly dependence of the CDOM light absorption by salinity and chlorophyll a concentrations was explored. In 2003, neither DOC nor CDOM were linearly correlated with salinity, due to an exceptionally low Po river inflow. Though the CDOM absorbance coefficients showed a higher content of chromophoric dissolved organic matter in 2004 with respect to 2003, the spectroscopic features confirmed that the qualitative nature of CDOM was quite similar in both years. CDOM and DOC underwent a conservative mixing, only after relevant Po river freshets, and a change in optical features with an increase of the specific absorption coefficient was observed, suggesting a prevailing terrestrial origin of dissolved organic matter. PMID:20416946

Berto, D; Giani, M; Savelli, F; Centanni, E; Ferrari, C R; Pavoni, B

2010-07-01

17

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

Science.gov (United States)

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

Rittenhouse, Chadwick D; Rissman, Adena R

2015-02-01

18

Temperance.  

Digital Repository Infrastructure Vision for European Research (DRIVER)

The kind of temperance discussed is the virtue of moderation concerning the pleasures of eating and drinking. A person lacks this moderation if either his desire for such pleasures causes conflicts with his own standards of appropriate behaviour or the standards themselves attach too much importance to the pleasures concerned. Opinions vary about the proper status of these pleasures, but people surely value them too highly if they place them above their health or the moral duty not to cause u...

Telfer, E.

1990-01-01

19

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

Science.gov (United States)

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.

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

2015-01-01

20

Winter photosynthetic activity of twenty temperate semi-desert sand grassland species.  

Science.gov (United States)

The winter photosynthetic activity (quantified by net CO(2) assimilation rates and chlorophyll (Chl) a fluorescence parameters) of 20 plant species (including two lichens and two mosses) of a Hungarian temperate semi-desert sand grassland was determined on one occasion per year in 1984, 1989 and 1994. Throughout winter, the overwintering green shoots, leaves or thalli were regularly exposed to below zero temperatures at night and daytime temperatures of 0-5 degrees C. In situ tissue temperature varied between -2.1 and +6.9 degrees C and the photosynthetic photon flux density (PPFD) between 137 and 351 micromol m(-2)s(-1). Under these conditions 18 of the grassland species exhibited photosynthetic CO(2) uptake (range: vascular plants ca. 0.2-3.8 micromol m(-2)s(-1), cryptogams 0.3-2.79 micromol kg(-1)s(-1)) and values of 0.9-5.1 of the Chl fluorescence decrease ratio R(Fd). In 1984, Festuca vaginata and Sedum sexangulare had net CO(2) assimilation at leaf temperatures of -0.85 to -1.2 degrees C. In 1989, all species except Cladonia furcata showed net CO(2) assimilation at tissue temperatures of 0 to +3.3 degrees C, with the highest rates observed in Poa bulbosa and F. vaginata. The latter showed a net CO(2) assimilation saturation at a PPFD of 600 micromol m(-2)s(-1) and a temperature optimum between +5 and +18 degrees C. At the 1994 measurements, the photosynthetic rates were higher at higher tissue water contents. The two mosses and lichens had a net photosynthesis (range: 1.1-2.79 micromol CO(2)kg(-1)s(-1)) at 2 degrees C tissue temperature and at 4-5 degrees C air temperature. Ca. 80% of the vascular grassland plant species maintained a positive C-balance during the coldest periods of winter, with photosynthetic rates of 1.5-3.8 micromol CO(2)m(-2)s(-1). In an extremely warm beginning March of the relatively warm winter of 2006/2007, the dicotyledonous plants had much higher CO(2) assimilation rates on a Chl (range 6-14.9 micromol g(-1)Chl s(-1)) and on a dry weight basis (9-48 micromol kg(-1)dw s(-1)) than in the cold winter of 1994. However, the assimilation rates of the three investigated cryptogams (Tortula and two Cladonia) and the two grasses Festuca and Poa were not affected by this increase. The results indicate that the photosynthetic activity of temperate semi-desert sand grassland species can help somewhat in slowing the general CO(2) rise in winter and function as a potential carbon sink of the investigated semi-desert Hungarian grassland species. PMID:18346813

Tuba, Zoltán; Csintalan, Zsolt; Szente, Kálmán; Nagy, Zoltán; Fekete, Gábor; Larcher, Walter; Lichtenthaler, Hartmut K

2008-09-29

 
 
 
 
21

Winter stream temperature in the rain-on-snow zone  

Science.gov (United States)

Stream temperature is a principal determinant of aquatic ecosystem composition and productivity. There are increasing concerns that changes in land cover and climatic conditions could produce changes in stream thermal regimes that would be deleterious to existing aquatic communities. Most stream temperature research has focused on summer periods and few studies have examined winter periods despite the growing recognition of its biological importance. The winter thermal regimes of Pacific Northwest headwater streams, which provide vital winter habitat for salmonids and their food sources, may be particularly sensitive to changes in climate because they can remain ice-free throughout the year and are often located in rain-on-snow zones. This study examined winter stream temperature patterns and controls in small headwater catchments within the rain-on-snow zone at the Malcolm Knapp Research Forest, near Vancouver, British Columbia, Canada. Two working hypotheses were addressed by this study: (1) winter stream temperatures are primarily controlled by advective fluxes associated with runoff processes and (2) stream temperatures should be depressed during rain-on-snow events, compared to rain on bare ground, due to the cooling effect of rain passing through the snowpack prior to infiltrating the soil or being delivered to the stream as saturation-excess overland flow. These hypotheses were tested statistically using historical stream temperature data and modelled snowpack dynamics for a forested headwater catchment. When snow was not present, daily stream temperature during winter rain events tended to increase with increasing air temperature. However, when snow was present, stream temperature was capped at about 5 °C, regardless of air temperature. This historical analysis was complemented with detailed field data collected during the winter of 2011-2012 from an ongoing field study in a partially logged catchment. Stream temperature response to a large rain-on-snow event was compared to a rain-only event of similar magnitude. During the rain-on-snow event, stream temperature exhibited less variation and was similar to soil temperature measured at a near-stream site known to produce substantial subsurface stormflow. Both the historical and field studies support our hypotheses. A key implication is that climate warming may generate higher winter stream temperatures in the rain-on-snow zone due to both increased rain temperature and reduced cooling effect of snow cover.

Leach, J. A.; Moore, R. D.

2012-12-01

22

Role of temperate zone forests in the world carbon cycle: problem definition and research needs  

Energy Technology Data Exchange (ETDEWEB)

The proceedings of a workshop on carbon uptake and losses from temperate zone forests are presented. The goals of the workshop were to analyze existing data on growth and utilization of the temperate zone forest carbon pool and to identify further research needs in relation to the role of temperate forests in the global carbon cycle. Total standing stock and growth recovery transients were examined for most of the temperate region over a period from pre-settlement times to the present, with emphasis on the last three decades. Because of data availability, certain regions and topics were covered more in detail than others. Forest inventory data from most of the commercial timberlands of the north temperate zone suggest these forests have functioned over the past several decades as an annual sink for about 10/sup 9/ metric tons of carbon. Thus, net growth of these forests has withdrawn carbon from the atmosphere at a rate equivalent, approximately, to 50% of the annual rise in atmospheric carbon. Various data inadequacies make this estimate probably no more precise than plus or minus half of the value. Analysis of growth and vegetation changes in New England and the southeastern United States shows that forest biomass has partly recovered since extensive clearing took place in the 18th and 19th centuries. This regrowth represents a net withdrawal of carbon (carbon sink) from the atmosphere in recent decades, although the difference in pool size between present and original forests means that, in the longer term, the two regions have functioned as carbon sources.

Armentano, T.V.; Hett, J. (eds.)

1979-01-01

23

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

Science.gov (United States)

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 (Vcmax) 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

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

2015-01-01

24

Temperate zone sporadic-E maps /f/0/E/s/ greater than 7 MHz/  

Science.gov (United States)

Three maps are presented of f(0) sporadic-E greater than 7 MHz for temperate zones. During map preparation it was assumed that: (1) the geographical area would be between plus and minus 60 deg geomagnetic latitude, excluding the equatorial zone, (2) the maps would be for f(0) sporadic-E greater than 7 MHz, (3) sunspot cycle variation would be ignored, (4) one map would represent the peak sporadic-E period with a discontinuity at the geographic equator, (5) one map would represent non-peak periods with a discontinuity at the geographic equator, (6) one map would represent all twelve months with no equatorial discontinuity, and (7) previously determined coefficients for median and upper decile f(0) sporadic-E would be extrapolated to 7 MHz.

Smith, E. K.

1978-01-01

25

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

Directory of Open Access Journals (Sweden)

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.

J. C. Stager

2012-05-01

26

Photoreceptive oscillators within neurons of the premammillary nucleus (PMM) and seasonal reproduction in temperate zone birds.  

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The pathway for light transmission regulating the reproductive neuroendocrine system in temperate zone birds remains elusive. Based on the evidence provided from our studies with female turkeys, it is suggested that the circadian clock regulating reproductive seasonality is located in putatively photosensitive dopamine-melatonin (DA-MEL) neurons residing in the premammillary nucleus (PMM) of the caudal hypothalamus. Melanopsin is expressed by these neurons; a known photopigment which mediates light information pertaining to the entrainment of the clock. Exposure to a gonad stimulatory photoperiod enhances the activity of the DAergic system within DA-MEL neurons. DAergic activity encoding the light information is transmitted to the pars tuberalis, where thyroid-stimulating hormone, beta (TSH?) cells reside, and induces the release of TSH. TSH stimulates tanycytes lining the base of the third ventricle and activates type 2 deiodinase in the ependymal which enhances triiodothyronine (T3) synthesis. T3 facilitates the release of gonadotropin-releasing hormone-I which stimulates luteinizing hormone/follicle stimulating hormone release and gonad recrudescence. These data taken together with the findings that clock genes are rhythmically expressed in the PMM where DA-MEL neurons are localized imply that endogenous oscillators containing photoreceptors within DA-MEL neurons are important in regulating the DA and MEL rhythms that drive the circadian cycle controlling seasonal reproduction. PMID:23453962

Kosonsiriluk, Sunantha; Mauro, Laura J; Chaiworakul, Voravasa; Chaiseha, Yupaporn; El Halawani, Mohamed E

2013-09-01

27

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

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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...

Dubey, Sylvain; Shine, Richard

2011-01-01

28

Trace Metal Cycling Within the Riparian Wetland and Hyporheic Zones of a Northern Temperate Stream Catchment  

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Our study addresses watershed linkages to streams and lakes, focusing on trace element cycles and metal-binding ligand production and transport. The research is being carried out at an extensively instrumented stream catchment in the Northern Temperate Lakes Region of north-central Wisconsin - a system that is also under investigation by the NSF-funded Long Term Ecosystem Research (LTER) program and the USGS Water Energy and Biogeochemical Budgets (WEBB) program. Within the study system we have identified flow paths of contrasting redox, in addition to zones of positive and negative ground water recharge. Detailed temporal data sets of water and ligand chemistry data are being obtained from dense networks of nested piezometers and hyporheic samplers placed in these contrasting regions/flow paths. In addition to major element chemistry, data on over 25 trace metals are acquired using high-resolution ICP-MS. A suite of oxyanionic metals is included to assist in our interpretation of DOC and iron oxide/sulfide partitioning mechanisms. Along a predominantly oxic flow path from regional ground water to stream riparian porewaters, concentrations of both Mn and Zn drop markedly (10-100 fold). Arsenic is also lost to riparian and wetland sediments. In contrast, levels of Cu increase 2-3 fold from upland hillslope groundwater to stream riparian porewaters. The importance of sulfide and iron in regulating ground water fluxes of certain trace metals to the stream is evident when oxic and anoxic flow paths are compared. Levels of Cu in many anoxic regions (0.06 nM Cu, 50-700 nM sulfide, 30-40,000 nM Fe) are strikingly reduced from that observed in oxic zones (4-6 nM, Cu, <20 nM sulfide, 100 nM Fe). Studies are in progress to characterize the oxidation state of Cu in the contrasting micro-environments. Concentrations of both Zn and Tl are significantly lower (10 fold) along anoxic flow-paths than in oxic regions. Large seasonal variations in Pb levels are observed, with particularly elevated concentrations seen in spring, coinciding with greater DOC fluxes. Temporal variations in metal levels and fluxes, as driven by seasonality in hydrologic-forcing, will be emphasized in the paper.

Shafer, M. M.; Kerr, S.; Overdier, J.; Armstrong, D.

2004-12-01

29

Studies on partially melted zone in aluminium-copper alloy welds-effect of techniques and prior thermal temper  

International Nuclear Information System (INIS)

Partially melted zone (PMZ) of aluminium alloy welds is an important region and requires careful attention. This is mainly because PMZ in these materials is weak link in the weldments and is significantly affected by welding parameters. Microstructure changes in PMZ are related not only to welding heat input and techniques, but also depend on the initial thermal history of alloy (for example, whether it is in T6 or T87 condition etc.). Interestingly, not many detailed studies were available in this respect. In the present work, effect of prior thermal temper and welding techniques mainly continuous and pulsed current gas tungsten arc welding (GTAW) on the PMZ behaviour of AA2219 alloy was studied. Susceptibility to liquation was found to be high in T6 temper of AA2219 alloy than in T87. Pulsed current technique was found to improve the resistance to the susceptibility to liquation in PMZ

30

Studies on partially melted zone in aluminium-copper alloy welds-effect of techniques and prior thermal temper  

Energy Technology Data Exchange (ETDEWEB)

Partially melted zone (PMZ) of aluminium alloy welds is an important region and requires careful attention. This is mainly because PMZ in these materials is weak link in the weldments and is significantly affected by welding parameters. Microstructure changes in PMZ are related not only to welding heat input and techniques, but also depend on the initial thermal history of alloy (for example, whether it is in T6 or T87 condition etc.). Interestingly, not many detailed studies were available in this respect. In the present work, effect of prior thermal temper and welding techniques mainly continuous and pulsed current gas tungsten arc welding (GTAW) on the PMZ behaviour of AA2219 alloy was studied. Susceptibility to liquation was found to be high in T6 temper of AA2219 alloy than in T87. Pulsed current technique was found to improve the resistance to the susceptibility to liquation in PMZ.

Rao, K. Srinivasa [Department of Metallurgical and Materials Engineering, Indian Institute of Technology Madras, Chennai 600036 (India)]. E-mail: arunaraok@yahoo.com; Reddy, G. Madhusudan [Defense Metallurgical Research Laboratory, Hyderabad 500258 (India); Rao, K. Prasad [Department of Metallurgical and Materials Engineering, Indian Institute of Technology Madras, Chennai 600036 (India)

2005-08-25

31

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

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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 enhanced heterotrophic respiration and depressed gross primary productivity (GPP); a sustained drought during the summer of 2010 (maximum water table depth 36 cm below surface) was accompanied by a two-fold increase in total respiration and a 30% decrease in GPP. The cold preceding winter could also have contributed to lowering GPP, and disentangling the 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.

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

2014-05-01

32

Organic matter production during late summer-winter period in a temperate sea  

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The quantity and quality of fresh organic matter (OM) formed by primary production in relation to phytoplankton community structure was calculated for the late summer-winter 2009/2010 in the northern Adriatic Sea (Mediterranean). Phytoplankton species, as a direct measure of fresh OM, chlorophyll a, the OM pool (DOC and POC) and lipids, including classes, were analyzed. Data for temperature, salinity and nutrients enabled deeper insight into the conditions that promoted fresh OM production and associated processes at two stations of different trophic status. Phytoplankton growth was controlled by bottom regenerated nutrients and to lesser extent by riverine nutrients. The phytoplankton community was mainly dominated by nanoplankton. Species of moderate carbon content Chaetoceros compressus, Asterionellopsis glacialis, Leptocylindrus danicus and Bacteriastrum jadranum dominated the microplankton fraction. Availability of orthophosphates was the key factor influencing fresh OM production. POC varied from 37-522 ?g l-1. Freshphyto POC, i.e. carbon fixed in phytoplankton cells, contributed 7-79% to the POC pool. The DOC (890-1560 ?g l-1) level decreased during the investigated period. Calculation of fresh DOC, i.e. carbon fixed during primary production and released as dissolved OM, revealed it as a minor part (0-2%) of the DOC pool. Lipid concentrations varied from 9.9-55.0 ?g l-1 and 20.0-40.2 ?g l-1 in the particulate and dissolved fractions, respectively. Nutrient limitation caused increased synthesis of lipids, among which energy reserve lipids triacylglycerols, which are further immobilized for the construction of glycolipids with increasing depletion of orthophosphates.

Mari?, Daniela; Frka, Sanja; Godrijan, Jelena; Tomaži?, Igor; Penezi?, Abra; Djakovac, Tamara; Vojvodi?, Vjero?ka; Precali, Robert; Gašparovi?, Blaženka

2013-03-01

33

46 CFR 42.30-5 - Northern Winter Seasonal Zones and area.  

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...of the North Pacific Winter Seasonal Zone is the parallel of latitude 50° N. from the east coast of the Union of Soviet Socialist Republics, to the west coast of Sakhalin; thence the west coast of Sakhalin to the southern extremity of...

2010-10-01

34

Larval fish dynamics in the Nxaxo-Ngqusi Estuary Complex in the warm temperate–subtropical transition zone of South Africa  

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Full Text Available The larval fish assemblage was investigated in the permanently open Nxaxo-Ngqusi Estuary Complex, situated in the subtropical–warm temperate biogeographic boundary zone of South Africa. Larval and early juvenile fishes were collected in summer and winter of 2007 and 2008 using a mixed method approach by boat-based plankton tows in mid-channel waters and seine net hauls along the margins. In total, 20 455 fishes were collected representing 21 families and 40 taxa, of which 13 900 fishes were from mid-channel sites (15 families and 21 taxa. Seine net hauls along the estuary margins produced 6550 fishes representing 18 families and 33 taxa. Gobiidae was the dominant fish family in the mid-channel waters followed by the Clupeidae whereas the opposite was found in marginal waters. Estuary-resident larvae were the dominant group in the estuary complex. The catches typically reflected a more warmtemperate community, although subtropical-associated species were present. Fish density in mid-channel waters was higher in the Ngqusi arm than that of the Nxaxo arm, whereas along the marginal waters, CPUE was higher in the latter. Fish densities in mid-channel waters and PUE along the margins were typically higher in summer.

T.H. Wooldridge

2011-10-01

35

Seasonal changes in the spatial distribution of phytoplankton in small, temperate-zone lakes  

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Sampling across two N Minnesota small lakes shows that phytoplankton patchiness is greatly enhanced during winter ice-cover relative to the open-water seasons of exposure to wind stress and rapid turbulent mixing. -Authors

Cloern, J.E.; Alpine, A.E.; Cole, B.E.; Heller, T.

1992-01-01

36

Biological, chemical and physical characteristics of downwelling and upwelling zones in the hyporheic zone of a north-temperate stream  

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Along a single stream riffle, there is a typical flow pattern in which surface water enters the hyporheic zone in a downwelling zone at the head of the riffle and hyporheic water returns to the stream surface in an upwelling zone at the tail of the riffle. Distinct patterns of physical and chemical conditions in the hyporheic zone are likely to determine patterns of microbial activity and occurrence of hyporheic fauna. Interstitial water and core samples were taken at three depths in the down...

Franken, R. J. M.; Storey, R. G.; Williams, D. D.

2001-01-01

37

Winter Temperature Response to Large Tropical Volcanic Eruptions in Temperate Western North America: Relationship to ENSO Phases  

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In light of anthropogenic climate forcing, significant evaluation of the climate system's response to a range of forcing factors has been undertaken. Responses to large tropical volcanic eruptions are a key focus area. Paleoclimatology offers a unique vehicle to extend the study of these responses over much longer periods than those available from instrumental data. In this work, we present a set of annually-resolved, late-winter temperature responses in temperate western North America over 1500-1980 CE, and evaluate, from a regional perspective, evidence that large tropical eruptions show a tendency towards an initial El Niño (EN) response followed by a delayed La Niña (LN) (c.f. Li et al., 2013, DOI:10.1038/NCLIMATE1936). The proxy information are primarily tree ring widths and some ring density data from the target reconstruction region (30-55° N, 95-130° W) and northern Mexico, which are calibrated and validated against 5x5° gridded instrumental temperature data. Calibration uses an optimized form of principal components spatial regression, and well-validated reconstructions (for both the regional average and spatially) were able to be achieved for the February-March (FM) period. The reconstructions are additionally validated by their capacity to resolve known regional composite EN and LN late-winter temperature patterns. Superposed epoch analysis (SEA, n=13) was used to determine the composite responses for a sequence of post-volcanic-event years. Results do not show an initial EN-like regional response, but do show LN-like patterns in post-event Years 3-5. The correlations of the SEA patterns for Years 3-4 with the LN regional composite are significant based on correlations observed in ensembles of random-event-year SEAs, which account for the strong regional ENSO teleconnection. Relative homogeneity of the SEA response for each post-event year is evaluated as the amplitude (signal) of the SEA composite relative to its variance (noise) across events. Relative to the same metric observed from the random-event-year SEAs, these S/N ratios are significant in the portions of the domain with the strongest anomalies in Years 1-4, especially Year 3, and then tend towards uniformly low/insignificant values indicating lessening entrainment across individual events as time progresses. Post-event 500mb FM geopotential height composites from the 20th Century Reanalysis (1871-2011 CE, n=5) are generally consistent with the SEA temperature patterns. In particular, the Year 1 pressure composite does not cohere with ENSO-related pressure composites, consistent with the very weak/weak pattern correlations this year shows with the EN/LN temperature composites; and the pressure composite in North America and the adjacent Pacific and Atlantic regions in Year 3 is strongly LN-like, consistent with the relatively strong pattern correlation this year shows with the LN temperature composite and the S/N results. The weakening entrainment across eruptions as post-event time progresses from Year 3 in the S/N results is also consistent with more variable pressure composites noted after that time. The LN-like response in Years 3-5 exhibits a slight shift of its southern warm anomaly to the north and west relative to composite LN conditions, which is isolated as a specifically post-eruption feature.

Wahl, E. R.; Diaz, H. F.; Smerdon, J. E.

2013-12-01

38

The hyporheic zone as a source of dissolved organic carbon and carbon gases to a temperate forested stream  

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The objective of this study was to examine chemical changes in porewaters that occur over small scales (cm) as groundwater flows through the hyporheic zone and discharges to a stream in a temperate forest of northern Wisconsin. Hyporheic-zone porewaters were sampled at discrete depths of 2, 10, 15, 61, and 183 cm at three study sites in the study basin. Chemical profiles of dissolved organic carbon (DOC), CO2, CH4, and pH show dramatic changes between 61 cm sediment depth and the water-sediment interface. Unless discrete samples at small depth intervals are taken, these chemical profiles are not accounted for. Similar trends were observed at the three study locations, despite each site having very different hydraulic-flow regimes. Increases in DOC concentration by an order of magnitude from 61 to 15 cm depth with a corresponding decrease in pH and rapid decreases in the molecular weight of the DOC suggest that aliphatic compounds (likely organic acids) are being generated in the hyporheic zone. Estimated efflux rates of DOC, CO2, and CH4 to the stream are 6.2, 0.79, 0.13 moles m2 d-1, respectively, with the vast majority of these materials produced in the hyporheic zone. Very little of these materials are accounted for by sampling stream water, suggesting rapid uptake and/or volatilization.

Schindler, J.E.; Krabbenhoft, D.P.

1998-01-01

39

Spatially explicit modeling of conflict zones between wildlife and snow sports: prioritizing areas for winter refuges.  

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Outdoor winter recreation exerts an increasing pressure upon mountain ecosystems, with unpredictable, free-ranging activities (e.g., ski mountaineering, snowboarding, and snowshoeing) representing a major source of stress for wildlife. Mitigating anthropogenic disturbance requires the spatially explicit prediction of the interference between the activities of humans and wildlife. We applied spatial modeling to localize conflict zones between wintering Black Grouse (Tetrao tetrix), a declining species of Alpine timberline ecosystems, and two free-ranging winter sports (off-piste skiing [including snow-boarding] and snowshoeing). Track data (snow-sports and birds' traces) obtained from aerial photographs taken over a 585-km transect running along the timberline, implemented within a maximum entropy model, were used to predict the occurrence of snow sports and Black Grouse as a function of landscape characteristics. By modeling Black Grouse presence in the theoretical absence of free-ranging activities and ski infrastructure, we first estimated the amount of habitat reduction caused by these two factors. The models were then extrapolated to the altitudinal range occupied by Black Grouse, while the spatial extent and intensity of potential conflict were assessed by calculating the probability of human-wildlife co-occurrence. The two snow-sports showed different distribution patterns. Skiers' occurrence was mainly determined by ski-lift presence and a smooth terrain, while snowshoers' occurrence was linked to hiking or skiing routes and moderate slopes. Wintering Black Grouse avoided ski lifts and areas frequented by free-ranging snow sports. According to the models, Black Grouse have faced a substantial reduction of suitable wintering habitat along the timberline transect: 12% due to ski infrastructure and another 16% when adding free-ranging activities. Extrapolating the models over the whole study area results in an overall habitat loss due to ski infrastructure of 10%, while there was a > 10% probability of human-wildlife encounters on 67% of the remaining area of suitable wintering habitat. Only 23% of the wintering habitat was thus free of anthropogenic disturbance. By identifying zones of potential conflict, while rating its relative intensity, our model provides a powerful tool to delineate and prioritize areas where wildlife winter refuges and visitor steering measures should be implemented. PMID:21639058

Braunisch, Veronika; Patthey, Patrick; Arlettaz, Raphaël

2011-04-01

40

Winter energy behaviour in multi-family block buildings in a temperate-cold climate in Argentina  

Energy Technology Data Exchange (ETDEWEB)

This paper analyzes the thermal and energy behaviour of apartments in three-story block buildings located along a NE-SW axis (azimuth = 120 ) in a temperate-cold climate (latitude: 36 57'; longitude: 64 27') in the city of Santa Rosa, La Pampa, central Argentina. Four apartments had been monitored during May and June 2009. Three of them are located in Block 126. Two of these apartments face South: 15 and 23 on the SE end, ground and first floor, respectively; 18 faces N on the second floor. Finally apartment, 12 is located in Block 374, on the first floor, faces N and shows a carpentry-closed balcony. The purpose of this work is - to study the evolution of the indoor temperature in each apartment; to analyze energy consumption and comfort conditions; to study energy potential and energy intervention in order to reduce energy consumption; to analyze bioclimatic alternatives feasibility and the possibility to extrapolate results to all blocks. On the basis of the analysis of natural gas historical consumption records, results showed that regarding heating energy consumption during the period May-June, Apartment 12, facing N, with its only bedroom facing NW and its carpentry-closed, transparent glass balcony, presented a mean temperature of 21.2 C, using a halogen heater for 6 h/day between 9 pm and 2 am (0.16 kWh/day/m{sup 2}). Apartment 15, on the SE end, first floor of the block consumed 22.5 kWh/day (0.43 kWh/day/m{sup 2}) (mean temperature = 22.2 C). Apartment 23, located on the second and top floor (on top of Apartment 15) with higher energy loss, consumed 28 kWh/day (0.54 kWh/day/m{sup 2}) (mean temperature 23.7 C). Apartment 18, also on the second floor and facing N, located in the centre and with its only bedroom facing SE, consumed 18.8 kWh/day (0.48 kWh/day/m{sup 2}) (mean temperature = 22.3 C). Apartment 23, with higher thermal loss through its envelope, but with heat transfer from the apartment located below, is the one that showed the highest level of consumption/m{sup 2}. Closing the balcony with carpentry produced an important reduction of energy consumption while reaching comfort conditions. The analysis of the experimental results allowed: (a) to determine through analysis of historical consumption of natural gas prior to the year 2009 that the owner lived under conditions of comfort, (b) to evaluate possible interventions in the building that would lead to saving heating energy. Thermal insulation of roof and envelope appears as the most feasible alternative whereas closing balconies constitute a very good design option in winter. (author)

Filippin, C. [CONICET - CC302, Santa Rosa, 6300 La Pampa (Argentina); Larsen, S. Flores [CONICET - CC302, Santa Rosa, 6300 La Pampa (Argentina); INENCO - Instituto de Investigaciones en Energias No Convencionales, U.N.Sa., CONICET, Avda. Bolivia 5150 - CP 4400, Salta Capital (Argentina); Mercado, V. [LAHV-Laboratorio de Ambienet Humano y Vivienda (INCIHUSA-CCT-CONICET) (Argentina)

2011-01-15

 
 
 
 
41

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)

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.

Szczucinski, W.

2013-12-01

42

Plankton assemblages in the ice edge zone of the Weddell Sea during the austral winter  

Science.gov (United States)

Plankton studies in Antarctic waters have emphasized the importance of diatoms. The species composition, abundances and contribution to biomass of the other planktonic groups are stil poorly documented. This is particularly true for the heterotrophic members of the nano- and microplankton assemblage. As part of the Antarctic Marine Ecosystem Research in the Ice age Zone (AMERIEZ) program, we sampled nano- and microplankton across the ice edge zone during the austral winter. A variety of microscopial techniques allowed us to the composition, trophic mode and biomass of the spectrum of organisms that make up the winter plankton assemblage. Total nano- and microplankton biomass in the upper 100 meters of the water column ranged from 0.3 to 0.6 gC m -2. The biomass composition of plankton assemblages among the stations was relatively uniform throughout the ice edge zone; however, the autotrophic flagellates and dinoflagellates showed significantly higher biomass at the ice edge or in open water relative to ice covered stations. The heterotrophic biomass (protozooplankton) exceeded the biomass of phytoplankton at most stations. Among the autotrophic forms, dinoflagellates made up 38% of the biomass, followed by other autotrophic flagellates (35%) and diatoms (27%). The phytoplankton biomass was dominated by nanoplankton (algae and protozoans. The abundance of athecate dinoflagellates, both autotrophic and heterotrophic forms, was unusual and warrants further investigation of the role of these organisms in the Antarctic plankton community. Generally low production and the high abundance of heterotrophic organisms relative to the phytoplankton, suggests the protozooplankton will be important in utilizing winter primary and bacterial production and transferring this production to higher levels of the food web.

Garrison, David L.; Buck, Kurt R.; Gowing, Marcia M.

1991-07-01

43

Molecular data and ecological niche modelling reveal the phylogeographic pattern of Cotinus coggygria (Anacardiaceae) in China's warm-temperate zone.  

Science.gov (United States)

The phylogeography of common and widespread species helps to elucidate the history of local flora and vegetation. In this study, we selected Cotinus coggygria, a species widely distributed in China's warm-temperate zone. One chloroplast DNA (cpDNA) region and ecological niche modelling were used to examine the phylogeographic pattern of C. coggygria. The cpDNA data revealed two phylogeographic groups (Southern and Northern) corresponding to the geographic regions. Divergence time analyses revealed that divergence of the two groups occurred at approximately 147,000 years before the present (BP), which coincided with the formation of the downstream area of the Yellow River, indicating that the Yellow River was a weak phylogeographic divide for C. coggygria. The molecular data and ecological niche modelling also indicated that C. coggyria did not experience population expansion after glaciations. This study thus supports the fact that Pleistocene glacial cycles only slightly affected C. coggygria, which survived in situ and occupied multiple localised glacial refugia during glaciations. This finding is contrary to the hypothesis of large-scale range habitat contraction and retreat into a few main refugia. PMID:24494998

Wang, W; Tian, C Y; Li, Y H; Li, Y

2014-11-01

44

The response of slope and channel systems to various types of extreme rainfall: A comparison between the temperate zone and humid tropics  

Science.gov (United States)

The mountain slopes and river channels of the temperate zone and of the humid tropics are modelled by various types of extreme rainfall. In the Flysch Carpathians the leading role is played by continuous rains causing floods and landslides, rainy seasons (wet years) mobilizing deep landslides and, to a smaller degree by local downpours. In the Darjeeling Himalaya with young relief and uplift tendency, the main influence on modelling the mountain slopes and river channels have been the extreme continuous rains separated by several decades of normal rainy season, playing the preparatory or relaxation role with simultaneous transformation of slopes and river channels. In both cases human impact has caused the acceleration of runoff and mobilization of sediment. The higher extremes of precipitation and steep slopes in the humid tropics are balanced (to some extent) in temperate zones by the lower infiltration rates and lower thresholds of mass mobility on the gentle slopes originated in the periglacial environment.

Froehlich, Wojciech; Starkel, Leszek

1995-03-01

45

Litter decomposition and soil respiration in response to increased rainfall variability, winter warming and altered cutting frequency in a temperate grassland  

Science.gov (United States)

Climate change is likely to alter decomposition rates through direct effects on soil biotic activity and indirect effects on litter quality with possible impacts on the global carbon budget and nutrient cycling. Currently, there is an urgent need to study combined effects of various climatic drivers and of agricultural practise on decomposition. In an in-situ litter bag experiment, we studied effects of rainfall variability (including drought plus heavy rain pulses and regular irrigation) interacting with winter warming and increased winter precipitation and with changes in cutting frequency, on decomposition in a temperate grassland. Litter bags contained mixed and species-specific litter out of all different climate and land-use manipulations and were placed within the plots of litter origin. Moreover, we aimed to disentangle causes for altered decomposition by following two further approaches: To study effects of changed leaf chemicals due to the manipulations we placed litter out of the experiment that has been pre-exposed to the manipulations before on an untreated standard plot outside the experiment. To assess effects of changed soil faunal activity, we investigated decomposition of standard material under differing rainfall variability. We further compare the observed decomposition results with soil respiration data. Decomposition was reduced when litter bags were exposed to drought for six weeks within an 11 months period. Neither additional winter rain nor winter warming had an effect on decomposition, probably because winter warming reduced snow cover and increased variability of surface temperatures. Climate manipulations did not change litter quality. Further, decomposition on the untreated standard plot was not affected by the climate manipulations that the litter previously was exposed to. Thus, reduced decomposition under extreme rainfall variability and drought may be mainly caused by a decrease in soil biotic activity, as indicated by reduced decomposition of standard material during drought. More frequent cutting strongly stimulated decomposition, however, this stimulating effect was absent under extreme rainfall variability including drought. The stimulation of decomposition under more frequent cutting was attributed to changes in litter quality, namely a decrease in C/N ratio. Accordingly, litter from more frequently cut communities decomposed faster on the untreated control plot outside the experiment. Projected increases in drought frequency and increased rainfall variability under climate change may inhibit decomposition and alter nutrient and carbon cycling along with soil quality. Especially decomposition in frequently cut grassland appears vulnerable towards drought.

Kreyling, Juergen; Walter, Julia; Grant, Kerstin; Beierkuhnlein, Carl; Jentsch, Anke

2013-04-01

46

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

Science.gov (United States)

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.

Dragovich, D.

1980-06-01

47

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

Digital Repository Infrastructure Vision for European Research (DRIVER)

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...

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

2012-01-01

48

Patterns of habitat selection and use by Macaca mulatta tcheliensis in winter and early spring in temperate forest, Jiyuan, China  

Digital Repository Infrastructure Vision for European Research (DRIVER)

The chosen habitat of any animal species comprises a range of environmental features that provide adequate resources for its continuous survival. Consequently, the criteria of habitat selection by animals, combines a wider spectrum of both environmental and extrinsic factors, with major prerequisites based on food resources, availability of shelter and suitable ethics for procreation. From this study, conducted in winter and early spring, at Mt. Wangwushan area, located on N 35...

Xie, Dong-ming; Lu, Ji-qi; Sichilima, Alfred Matafwali; Wang, Bai-shi

2012-01-01

49

Effect of summer throughfall exclusion, summer drought, and winter snow cover on methane fluxes in a temperate forest soil  

Science.gov (United States)

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.

Borken, W.; Davidson, E.A.; Savage, K.; Sundquist, E.T.; Steudler, P.

2006-01-01

50

Biological soil crusts are the main contributor to winter soil respiration in a temperate desert ecosystem of China  

Science.gov (United States)

Aims Biological soil crusts (BSCs) are a key biotic component of desert ecosystems worldwide. However, most studies carried out to date on carbon (fluxes) in these ecosystems, such as soil respiration (RS), have neglected them. Also, winter RS is reported to be a significant component of annual carbon budget in other ecosystems, however, we have less knowledge about winter RS of BSCs in winter and its contribution to carbon cycle in desert regions. Therefore, the specific objectives of this study were to: (i) quantify the effects of different BSCs types (moss crust, algae crust, physical crust) on the winter RS; (ii) explore relationships of RS against soil temperature and water content for different BSCs, and (iii) assess the relative contribution of BSCs to the annual amount of C released by RS at desert ecosystem level. Methods Site Description The study sites are located at the southeast fringe of the Tengger Desert in the Shapotou region of the Ningxia Hui Autonomous Region [37°32'N and 105°02'E, at 1340 m above mean sea level (a.m.s.l.)], western China. The mean daily temperature in January is -6.9°C , while it is 24.3°C in July. The mean annual precipitation is 186 mm, approximately 80% of which falls between May and September. The annual potential evaporation is 2800 mm. The landscape of the Shapotou region is characterized by large and dense reticulate barchans chains of sand dunes that migrate south-eastward at a velocity of 3-6 m per year. The soil is loose, infertile and mobile and can thus be classified as orthic sierozem and Aeolian sandy soil. Additionally, the soil has a consistent gravimetric water content that ranges from 3 to 4%. The groundwater in the study area is too deep (>60 m) to support large areas of the native vegetation cover; therefore, precipitation is usually the only source of freshwater. The predominant native plants are Hedysarum scoparium Fisch. and Agriophyllum squarrosum Moq., Psammochloa cillosa Bor, which scattered distribute with cover about 1% of the entire study area. Prior to revegetation, straw-checkerboards approximately 1×1 m2 in area were constructed using wheat or rice straw to stabilize the dune surface and allow time for the planted xerophytic shrubs to adapt to the new environment. In 1956, the following 2-year-old xerophytic shrub seedlings were planted within the checkerboard at a density of 16 individuals per 100 m2 and grown without irrigation: Artemisia ordosica Krasch, H. scoparium Fisch, Calligonum mongolicum Turc'z, Caragana microphylla Lam., Caragana korshinskii Kom, Salix gordejevii and Atraphaxis bracteata A.Los. The stabilized area was then expanded to parallel areas in 1964 and 1982 using the same method and species. As a result, the initial stages of change that have occurred at these sites were similar. After more than fifties years succession, the predominant plants are semi-shrubs, shrubs, forbs, and grasses at present and BSCs formed. The common BSCs in the region may be dominated by cyanobacteria, algae, lichens and mosses, or any combination of these organisms. Cyanobacteria species include Microcolous vaginatus Gom., Hydrocoleus violacens Gom., Lyngbya crytoraginatus Schk., Phormidium amblgum Gom., P. autumnale (Ag.) Gom., P. foveolarum (Mont.) Gom. and Phormidium luridum (Kutz) Gom. etc; algal species mainly include Anabaena azotica Ley, Euglena sp., Hantzschia amphioxys var capitata Grum, Oscillatoria obscura Gom., O. pseudogeminate G. Schm. And Scytonema javanicum (Kutz) Bornet Flash etc; lichen species include Collema tenax (Sw.) Ach., Endocarpon pusillum Hedw.; and moss species are dominated by Bryum argenteum Hedw., Didymodon constrictus (Mitt.) Saito., Tortula bidentata Bai Xue Liang and T. desertorum Broth.. Experimental Design and Rs measurements On October 2010, We selected the moss-dominated BSCs at four revegetation sites and natural vegetation sites, in which 3 replicated plots were selected randomly. In each plot, olyvinyl chloride (PVC) collar (lenth 10 cm, internal diameter 10cm ) were inserted 7 cm into the soil. During the

He, M. Z.

2012-04-01

51

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

DEFF Research Database (Denmark)

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.

Chirinda, Ngoni; Roncossek, Svenja Doreen

2014-01-01

52

Selection on a eumelanic ornament is stronger in the tropics than in temperate zones in the worldwide-distributed barn owl.  

Science.gov (United States)

Spatial variation in the pattern of natural selection can promote local adaptation and genetic differentiation between populations. Because heritable melanin-based ornaments can signal resistance to environmentally mediated elevation in glucocorticoids, to oxidative stress and parasites, populations may vary in the mean degree of melanic coloration if selection on these phenotypic aspects varies geographically. Within a population of Swiss barn owls (Tyto alba), the size of eumelanic spots is positively associated with survival, immunity and resistance to stress, but it is yet unknown whether Tyto species that face stressful environments evolved towards a darker eumelanic plumage. Because selection regimes vary along environmental gradients, we examined whether melanin-based traits vary clinally and are expressed to a larger extent in the tropics where parasites are more abundant than in temperate zones. To this end, we considered 39 barn owl species distributed worldwide. Barn owl species living in the tropics displayed larger eumelanic spots than those found in temperate zones. This was, however, verified in the northern hemisphere only. Parasites being particularly abundant in the tropics, they may promote the evolution of darker eumelanic ornaments. PMID:19032496

Roulin, A; Wink, M; Salamin, N

2009-02-01

53

Diversification rates and chromosome evolution in the most diverse angiosperm genus of the temperate zone (Carex, Cyperaceae).  

Science.gov (United States)

The sedge family (Cyperaceae: Poales; ca. 5600 spp.) is a hyperdiverse cosmopolitan group with centres of species diversity in Africa, Australia, eastern Asia, North America, and the Neotropics. Carex, with ca. 40% of the species in the family, is one of the most species-rich angiosperm genera and the most diverse in temperate regions of the Northern Hemisphere, making it atypical among plants in that it inverts the latitudinal gradient of species richness. Moreover, Carex exhibits high rates of chromosome rearrangement via fission, fusion, and translocation, which distinguishes it from the rest of the Cyperaceae. Here, we use a phylogenetic framework to examine how the onset of contemporary temperate climates and the processes of chromosome evolution have influenced the diversification dynamics of Carex. We provide estimates of diversification rates and map chromosome transitions across the evolutionary history of the main four clades of Carex. We demonstrate that Carex underwent a shift in diversification rates sometime between the Late Eocene and the Oligocene, during a global cooling period, which fits with a transition in diploid chromosome number. We suggest that adaptive radiation to novel temperate climates, aided by a shift in the mode of chromosome evolution, may explain the large-scale radiation of Carex and its latitudinal pattern of species richness. PMID:22366369

Escudero, Marcial; Hipp, Andrew L; Waterway, Marcia J; Valente, Luis M

2012-06-01

54

An unusual occurrence of surficial anhydrite in a moist temperate zone: Example from the lockport formation (Middle Silurian) of New York  

Science.gov (United States)

Gypsum is the most common sulfate mineral that occurs on the earth's surface or in the shallow subsurface, whereas anhydrite occurs in relatively deeper subsurface settings. Anhydrite is described here from the Lockport Formation (Middle Silurian) of New York. This occurrence is unusual as the anhydrite is present on the surface in a temperate climatic zone where the regional rainfall averages ˜80 cm per year. The anhydrite is of nodular form and has an incomplete rind composed of megaquartz. Petrographic characteristics and megafeatures indicate that formation of the nodule followed shortly after dolomitization. Growth of the nodule probably took place in an open space. Overall sequence of events is indicated to be: dolomitization ? dissolution of gypsum ? precipitation of anhydrite ? partial silicification of the nodule surface.

Shukla, Vijai; Friedman, Gerald M.

1981-07-01

55

Holocene climate variability in the winter rainfall zone of South Africa  

Directory of Open Access Journals (Sweden)

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.

S. Weldeab

2012-06-01

56

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)

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

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

57

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)

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.

Poeplau, Christopher; Don, Axel

2011-01-01

58

Field observations of climbing behavior and seed predation by adult ground beetles (Coleoptera: Carabidae) in a lowland area of the temperate zone.  

Science.gov (United States)

Granivory is a specialized food habit in the predominantly carnivorous beetle family Carabidae. Most studies of carabid granivory have been conducted under laboratory conditions; thus, our knowledge of the feeding ecology of granivorous carabids in the field is insufficient. I conducted field observations of climbing behavior and seed predation by adult carabids in a lowland area of eastern Japan, from early October to late November in 2008. This is the first systematic field observation of the feeding ecology of granivorous carabids in the temperate zone. In total, 176 carabid individuals of 11 species were observed, with 108 individuals feeding on plant seeds/flowers. Each carabid species was primarily observed feeding on a particular plant species. Frequently observed combinations were: Amara gigantea Motschulsky on Humulus scandens (Loureiro) Merrill (Moraceae) seed, Amara lucens Baliani on Artemisia indica Willdenow (Asteraceae) flower, and Amara macronota (Solsky) and Harpalus (Pseudoophonus) spp. on Digitaria ciliaris (Retzius) Koeler (Poaceae) seed. In all but one species, the sex ratio of individuals observed feeding was female-biased. In Am. gigantea and Am. macronota, a larger proportion of females than males ate seeds. In the three Amara species, copulations on plants, with the female feeding on its seeds/flowers, were often observed. These observations may indicate that, whereas females climb onto plants to feed on seeds, males climb to seek females for copulation rather than forage. Because granivorous carabids play important roles as weed-control agents in temperate agro-ecosystems, the present results would provide valuable basic information for future studies on this subject. PMID:22546452

Sasakawa, Kôji

2010-10-01

59

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)

60

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  

Digital Repository Infrastructure Vision for European Research (DRIVER)

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 ...

TERESA PARADA; Lusk, Christopher H.

2011-01-01

 
 
 
 
61

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.

62

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)

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.

Alexandre Couto Rodrigues

2005-04-01

63

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)

Full Text Available SciELO Brazil | Language: Portuguese Abstract in portuguese 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.

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

2005-04-01

64

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

DEFF Research Database (Denmark)

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.

Wohlfart, T; Exbrayat, J F

2012-01-01

65

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

Directory of Open Access Journals (Sweden)

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.

T. Wohlfart

2012-06-01

66

Immune response to an endotoxin challenge involves multiple immune parameters and is consistent among the annual-cycle stages of a free-living temperate zone bird.  

Science.gov (United States)

Trade-offs between immune function and other physiological and behavioural processes are central in ecoimmunology, but one important problem is how to distinguish a reallocation of resources away from the immune system from a reallocation or redistribution within the immune system. While variation in baseline values of individual immune parameters is well established, studies in wild animals on multiple parameters during an immune response are lacking. It also remains to be tested whether and how immune responses correlate with baseline values that vary, for example, over the course of an annual cycle. We studied immunological responses to an endotoxin challenge in skylarks (Alauda arvensis), a partial migrant bird breeding in temperate zones. We compared birds injected with the endotoxin LPS with un-injected controls, characterizing immunological responses with leukocyte profiles, titres of lytic enzymes and natural antibodies, and concentrations of haptoglobin and heat shock proteins. We did this in five annual-cycle stages to test whether the response varied throughout the year. The endotoxin challenge affected six of 10 measured parameters. Lysis titres and proportions of heterophils increased; haptoglobin concentrations and proportions of lymphocytes, basophils and eosinophils decreased. The variable effects on different immune components demonstrate the complexity of an immune response. We found no evidence that the response differed between annual-cycle stages. The response was independent of baseline measures taken directly upon capture in the field, indicating that birds were facing no immunological ceiling when mounting an immune response. Values of five parameters collected under field conditions were significantly related to values taken under standardized laboratory conditions. We conclude that multiple parts of the immune system are modulated during an immunological response and that responses are not re-organized throughout the annual cycle. PMID:23531817

Hegemann, Arne; Matson, Kevin D; Versteegh, Maaike A; Villegas, Auxiliadora; Tieleman, B Irene

2013-07-15

67

Toxic potencies of metabolite(s) of non-cylindrospermopsin producing Cylindrospermopsis raciborskii isolated from temperate zone in human white cells.  

Science.gov (United States)

Cylindrospermopsis raciborskii (Nostocales, Cyanobacteria) has worldwide distribution and is well known for producing the toxic alkaloid, cylindrospermopsin (CYN). Strains unable to synthesize this compound but potentially toxic were recently identified in Europe. Here, for the first time the effect of cell-free extracts of a non-CYN-producing strain of C. raciborskii was studied in human cells (neutrophils and lymphocytes) isolated from healthy donors. The observed effects were compared to those induced by CYN (1.0-0.01 ?g mL(-1)). Short-term (1h) extract treatments resulted in altered viability of cells demonstrated by increased necrosis and apoptosis in neutrophils and elevated apoptosis in lymphocytes. CYN did not induce similar effects, regardless of the toxin concentration. Exposure of T-lymphocytes to 100% C. raciborskii extract in isolated and whole-blood 72 h cultures resulted in decrease of proliferation by 20.6% and 32.5%, respectively. In comparison, exposure to 1.0 ?g mL(-1) of CYN caused lymphocytes proliferation to be inhibited by 91.0% in isolated cultures and 56.5% in whole-blood assay. Significant antiproliferative properties were also found for 0.1 ?g mL(-1) of CYN in whole-blood culture. From the results we conclude that strains occurring in temperate zones may pose a threat to human health through the production of hitherto unknown metabolites that reveal a toxic pattern different to that of CYN. At the same time our study demonstrates that CYN is a powerful but slowly-acting toxin in human immune cells. PMID:25462304

Poniedzia?ek, Barbara; Rzymski, Piotr; Kokoci?ski, Miko?aj; Karczewski, Jacek

2015-02-01

68

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

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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.

Marta Ziemi?ska-Smyk

2004-12-01

69

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

Energy Technology Data Exchange (ETDEWEB)

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.

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

70

Spatial Distribution, Structure, Biomass, and Physiology of Microbial Assemblages across the Southern Ocean Frontal Zones during the Late Austral Winter.  

Science.gov (United States)

We examined the spatial distributions of picoplankton, nanoplankton, and microplankton biomass and physiological state relative to the hydrography of the Southern Ocean along 90 degrees W longitude and across the Drake Passage in the late austral winter. The eastern South Pacific Ocean showed some large-scale biogeographical differences and size class variability. Microbial ATP biomass was greatest in euphotic surface waters. The horizontal distributions of microbial biomass and physiological state (adenylate energy charge ratio) coincided with internal currents (fronts) of the Antarctic Circumpolar Current. In the Drake Passage, the biological scales in the euphotic and aphotic zones were complex, and ATP, total adenylate, and adenylate energy charge ratio isopleths were compressed due to the extension of the sea ice from Antarctica and constriction of the Circumpolar Current through the narrow passage. The physiological state of microbial assemblages and biomass were much higher in the Drake Passage than in the eastern South Pacific Ocean. The temperature of Antarctic waters, not dissolved organic carbon, was the major variable controlling picoplankton growth. Estimates of picoplankton production based on ATP increments with time suggest that production under reduced predation pressure was 1 to 10 mug of carbon per liter per day. Our results demonstrate the influence of large-scale hydrographic processes on the distribution and structure of microplankton, nanoplankton, and picoplankton across the Southern Ocean. PMID:16346777

Hanson, R B; Lowery, H K

1985-05-01

71

A study on optimum insulation thicknesses of external walls in hot summer and cold winter zone of China  

Energy Technology Data Exchange (ETDEWEB)

The employ of thermal insulation is one of the most effective ways of building energy conservation for cooling and heating. Therefore, the selection of a proper insulation material and the determination of optimum insulation thickness are particularly vital. Four typical cities of Shanghai, Changsha, Shaoguan and Chengdu are selected to represent A, B, C and D subzone of hot summer and cold winter zone in China, respectively. The optimum thicknesses of five insulation materials including expanded polystyrene, extruded polystyrene, foamed polyurethane, perlite and foamed polyvinyl chloride are calculated with a typical residential wall using solar-air cooling and heating degree-days analysis and P{sub 1}-P{sub 2} economic model. And then, life cycle total costs, life cycle savings and payback periods are calculated based on life cycle cost analysis. Considering different orientations, surface colors, insulation materials and climates, optimum thicknesses of the five insulations vary from 0.053 to 0.236 m, and the payback periods vary from 1.9 to 4.7 years over a lifetime of 20 years. The maximum life cycle savings are 54.4 /m{sup 2} in Shanghai, 54.8 /m{sup 2} in Changsha and 41.5 /m{sup 2} in Shaoguan (with a deep-colored northeast wall), and 39.0 /m{sup 2} in Chengdu (with a light-colored northwest wall). Finally, an approach to analyze economical efficiency of insulation materials is developed, result shows that expanded polystyrene is the most economic insulation material of the five because of the highest life cycle saving and lowest payback period. (author)

Yu, Jinghua; Yang, Changzhi; Tian, Liwei; Liao, Dan [College of Civil Engineering, Hunan University, Changsha, Hunan 410082 (China)

2009-11-15

72

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

73

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  

Digital Repository Infrastructure Vision for European Research (DRIVER)

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 i...

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

74

Spatial Distribution, Structure, Biomass, and Physiology of Microbial Assemblages across the Southern Ocean Frontal Zones during the Late Austral Winter  

Digital Repository Infrastructure Vision for European Research (DRIVER)

We examined the spatial distributions of picoplankton, nanoplankton, and microplankton biomass and physiological state relative to the hydrography of the Southern Ocean along 90° W longitude and across the Drake Passage in the late austral winter. The eastern South Pacific Ocean showed some large-scale biogeographical differences and size class variability. Microbial ATP biomass was greatest in euphotic surface waters. The horizontal distributions of microbial biomass and physiological state...

Hanson, Roger B.; Lowery, H. Kenneth

1985-01-01

75

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)

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.

Benjamin W. Tobin

2013-09-01

76

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)

77

ECONOMIC EVALUATION OF TECHNOLOGIES OF CULTIVATION OF MAIZE AFTER GRAIN AND WINTER WHEAT IN THE CONDITIONS OF THE PINNED LOWLANDS AGRO-LANDSCAPE OF THE CENTRAL ZONE OF THE KRASNODAR REGION ????????????? ?????? ?????????? ???????????? ???????? ?? ????? ? ?????? ??????? ? ???????? ????????-??????????? ????????????? ??????????? ???? ?????????????? ????  

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The article deals with the economic evaluation of seven studied alternative technologies for cultivation of winter wheat and corn in conditions of the pinned low-lands agro-landscapes of the Central zone of the Kras-nodar region. The high efficiency of the reclamation technology of cultivation has been revealed

Velikanova L. O.; Siso A. V.

2013-01-01

78

ECONOMIC EVALUATION OF TECHNOLOGIES OF CULTIVATION OF MAIZE AFTER GRAIN AND WINTER WHEAT IN THE CONDITIONS OF THE PINNED LOWLANDS AGRO-LANDSCAPE OF THE CENTRAL ZONE OF THE KRASNODAR REGION ????????????? ?????? ?????????? ???????????? ???????? ?? ????? ? ?????? ??????? ? ???????? ????????-??????????? ????????????? ??????????? ???? ?????????????? ????  

Directory of Open Access Journals (Sweden)

Full Text Available The article deals with the economic evaluation of seven studied alternative technologies for cultivation of winter wheat and corn in conditions of the pinned low-lands agro-landscapes of the Central zone of the Kras-nodar region. The high efficiency of the reclamation technology of cultivation has been revealed

Velikanova L. O.

2013-03-01

79

Temperature characteristics of winter roost-sites for birds and mammals: tree cavities and anthropogenic alternatives  

Science.gov (United States)

The microclimate of potential roost-sites is likely to be a crucial determinant in the optimal roost-site selection of endotherms, in particular during the winter season of temperate zones. Available roost-sites for birds and mammals in European high trunk orchards are mainly tree cavities, wood stacks and artificial nest boxes. However, little is known about the microclimatic patterns inside cavities and thermal advantages of using these winter roost-sites. Here, we simultaneously investigate the thermal patterns of winter roost-sites in relation to winter ambient temperature and their insulation capacity. While tree cavities and wood stacks strongly buffered the daily cycle of temperature changes, nest boxes showed low buffering capacity. The buffering effect of tree cavities was stronger at extreme ambient temperatures compared to temperatures around zero. Heat sources inside roosts amplified ? T (i.e., the difference between inside and outside temperatures), particularly in the closed roosts of nest boxes and tree cavities, and less in the open wood stacks with stronger circulation of air. Positive ? T due to the installation of a heat source increased in cold ambient temperatures. These results suggest that orchard habitats in winter show a spatiotemporal mosaic of sites providing different thermal benefits varying over time and in relation to ambient temperatures. At cold temperatures tree cavities provide significantly higher thermal benefits than nest boxes or wood stacks. Thus, in winter ecology of hole-using endotherms, the availability of tree cavities may be an important characteristic of winter habitat quality.

Grüebler, Martin U.; Widmer, Silv; Korner-Nievergelt, Fränzi; Naef-Daenzer, Beat

2014-07-01

80

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

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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.

F. Renou-Wilson

2014-04-01

 
 
 
 
81

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  

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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 abundanc...

Vidal, Osvaldo J.; Bannister, Jan R.; VÍCTOR SANDOVAL; YESSICA PÉREZ; CARLOS RAMÍREZ

2011-01-01

82

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  

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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...

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

2004-01-01

83

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)

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.

TERESA PARADA

2011-01-01

84

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)

Full Text Available SciELO Chile | Language: English Abstract in spanish 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.

TERESA, PARADA; CHRISTOPHER H., LUSK.

85

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)

86

FRIGIDA-related genes are required for the winter-annual habit in Arabidopsis  

Digital Repository Infrastructure Vision for European Research (DRIVER)

In temperate climates, the prolonged cold temperature of winter serves as a seasonal landmark for winter-annual and biennial plants. In these plants, flowering is blocked before winter. In Arabidopsis thaliana, natural variation in the FRIGIDA (FRI) gene is a major determinate of the rapid-cycling vs. winter-annual flowering habits. In winter-annual accessions of Arabidopsis, FRI activity blocks flowering through the up-regulation of the floral inhibitor FLOWERING LOCUS C (FLC). Most rapid-fl...

Michaels, Scott D.; Bezerra, Isabel C.; Amasino, Richard M.

2004-01-01

87

Comparison of seasonal soil microbial process in snow-covered temperate ecosystems of northern China.  

Science.gov (United States)

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 different phases of the year, understanding seasonal microbial process will increase our knowledge of biogeochemical cycling from the aspect of decomposition rates and corresponding nutrient dynamics. In this study, we measured soil microbial biomass, community composition and potential SOC mineralization rates in winter and summer, from six temperate ecosystems in northern China. Our results showed a clear pattern of increased microbial biomass C to nitrogen (N) ratio in most winter soils. Concurrently, a shift in soil microbial community composition occurred with higher fungal to bacterial biomass ratio and gram negative (G-) to gram positive (G+) bacterial biomass ratio in winter than in summer. Furthermore, potential SOC mineralization rate was higher in winter than in summer. Our study demonstrated a distinct transition of microbial community structure and function from winter to summer in temperate snow-covered ecosystems. Microbial N immobilization in winter may not be the major contributor for plant growth in the following spring. PMID:24667929

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

2014-01-01

88

Winter-to-summer evolution of pCO2 in surface water and air-sea CO2 flux in the seasonal ice zone of the Southern Ocean  

Science.gov (United States)

Partial pressure of CO2 (pCO2) in surface water and vertical profiles of the carbonate system parameters were measured during austral summer in the Indian sector of the Southern Ocean (64-67° S, 32-58° E) in January 2006 to understand the CO2 dynamics of seawater in the seasonal ice zone. Surface-water pCO2 ranged from 275 to 400 ?atm, and longitudinal variations reflected the dominant influence of water temperature and dilution by sea ice meltwater between 32 and 40° E and biological productivity between 40 and 58° E. Using carbonate system data from the temperature minimum layer (-1.9 °C < T < -1.5 °C, 34.2 < S < 34.5), we examined the winter-to-summer evolution of surface-water pCO2 and the factors affecting it. Our results indicate that pCO2 increased by as much as 32 ?atm, resulting mainly from the increase in water temperature. At the same time as changes in sea ice concentration and surface-water pCO2, the air-sea CO2 flux, which consists of the exchange of CO2 between sea ice and atmosphere, changed from -1.1 to +0.9 mmol C m-2 day-1 between winter and summer. These results suggest that, for the atmosphere, the seasonal ice zone acts as a CO2 sink in winter and a temporary CO2 source in summer immediately after the retreat of sea ice. Subsequent biological productivity likely decreases surface-water pCO2 and the air-sea CO2 flux becomes negative, such that in summer the study area is again a CO2 sink with respect to the atmosphere.

Nomura, D.; Yoshikawa-Inoue, H.; Kobayashi, S.; Nakaoka, S.; Nakata, K.; Hashida, G.

2014-10-01

89

Environmental Predictors of Seasonal Influenza Epidemics across Temperate and Tropical Climates  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Human influenza infections exhibit a strong seasonal cycle in temperate regions. Recent laboratory and epidemiological evidence suggests that low specific humidity conditions facilitate the airborne survival and transmission of the influenza virus in temperate regions, resulting in annual winter epidemics. However, this relationship is unlikely to account for the epidemiology of influenza in tropical and subtropical regions where epidemics often occur during the rainy season or transmit year-...

Tamerius, James D.; Shaman, Jeffrey; Alonso, Wladmir J.; Bloom-feshbach, Kimberly; Uejio, Christopher K.; Comrie, Andrew; Viboud, Ce?cile

2013-01-01

90

Adaptation to seasonality and the winter freeze  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Flowering plants initially diversified during the Mesozoic era at least 140 million years ago in regions of the world where temperate seasonal environments were not encountered. Since then several cooling events resulted in the contraction of warm and wet environments and the establishment of novel temperate zones in both hemispheres. In response, less than half of modern angiosperm families have members that evolved specific adaptations to cold seasonal climates, including cold acclimation, ...

Preston, Jill C.; Sandve, Simen R.

2013-01-01

91

[Temperate Legionella bacteriophage: discovery and characteristics].  

Science.gov (United States)

For the first time, temperate Legionella bacteriophage was isolated from organs of guinea pig infected with Philadelphia 1 strain of Legionella pneumophila. Negative colonies of bactriophage from 1.5 to 2.5 mm in diameter were detected. Central part of them was transparent and surrounded by peripheral zone of partial lysis. Electron microscopy showed that corpuscles of the phage consist from multifaceted elongated head of stretched hexagonal form and short tail. The bacteriophage lyzed bacteria, which cause Legionnaires' disease, and also had certain lytic activity against causative agent of tularemia. PMID:18819413

Grigor'ev, A A; Bondarev, V P; Borisevich, I V; Darmov, I V; Mironin, A V; Zolotarev, A G; Pogorel'ski?, I P; Ianov, D S

2008-01-01

92

Semipurity of tempered Deligne cohomology  

Digital Repository Infrastructure Vision for European Research (DRIVER)

In this paper we define the formal and tempered Deligne cohomology groups, that are obtained by applying the Deligne complex functor to the complexes of formal differential forms and tempered currents respectively. We then prove the existence of a duality between them, a vanishing theorem for the former and a semipurity property for the latter. The motivation of these results comes from the study of covariant arithmetic Chow groups. The semi-purity property of tempered Delig...

Burgos Gil, Jose? Ignacio

2007-01-01

93

Winter Festival.  

Science.gov (United States)

This is one of a series of elementary readers written in Cantonese and English and designed to familiarize children with the traditional major Chinese festivals celebrated by the Chinese in America. This booklet describes the occasion for the Winter Festival (the beginning of winter) and follows a Chinese-American family in its preparation for and…

Lew, Gordon

94

Seasonal dynamics of nitrogen fixation and the diazotroph community in the temperate coastal region of the northwestern North Pacific  

Science.gov (United States)

Nitrogen fixation in temperate oceans is a potentially important, but poorly understood process that may influence the marine nitrogen budget. This study determined seasonal variations in nitrogen fixation and nifH gene diversity within the euphotic zone in the temperate coastal region of the northwestern North Pacific. Nitrogen fixation as high as 13.6 nmolN L-1 d-1 was measured from early summer to fall when the surface temperature exceeded 14.2 °C and the surface nitrate concentration was low (? 0.30 ?M), although we also detected nitrogen fixation in subsurface layers (42-62 m) where nitrate concentrations were high (> 1 ?M). During periods with high nitrogen fixation, the nifH sequences of UCYN-A were recovered, suggesting that these groups played a key role in nitrogen fixation. The nifH genes were also recovered in spring and winter when nitrogen fixation was undetectable. These genes consisted of many sequences affiliated with Cluster III diazotrophs (putative anaerobic bacteria), which hitherto have rarely been reported to be abundant in surface diazotroph communities in marine environments.

Shiozaki, T.; Nagata, T.; Ijichi, M.; Furuya, K.

2015-01-01

95

Alcohol, Temperance & Prohibition  

Science.gov (United States)

That legendary man of letters, Samuel Johnson, once opined that â??Abstinence is as easy to me as temperance would be difficultâ?. Over the centuries, many have shared at least part of Johnsonâ??s sentiment as regards the temptations offered by spirits, and just as many have concerned themselves with the cause of cautioning others about alcohol and its potentially pernicious effects. The good people at Brown University have created this digital collection which includes a host of primary documents from the past several centuries, including broadsides, sheet music, and government publications. These items will be of great interest to anyone interested in the history of alcoholism, and how various forms of media were used to disseminate ideas and information about this phenomenon and the prohibition movement. Visitors can browse the collection by document creator, publisher, and general title. Another item of note here is the online essay â??Temperance and Prohibition Era Propaganda: A Study in Rhetoricâ? by Leah Rae Berk.

96

Carbon sinks in temperate forests  

Digital Repository Infrastructure Vision for European Research (DRIVER)

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...

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

2001-01-01

97

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

Science.gov (United States)

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).

Chase, B. M.

2013-12-01

98

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

Science.gov (United States)

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

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

99

Winter Weather  

Science.gov (United States)

... mold, environmental concerns, and coping with a disaster. Learn more. Disasters & Severe Weather Earthquakes Extreme Heat Floods Hurricanes Landslides Tornadoes Tsunamis Volcanoes Wildfires Winter Weather Language: English Español (Spanish) File Formats Help: How do I ...

100

Surviving Winter  

Science.gov (United States)

In this lesson designed to enhance literacy skills, students learn about the varied physical and behavioral adaptations that animals rely on to help them survive changing environmental conditions, such as the arrival of winter.

WGBH Educational Foundation

2010-12-13

 
 
 
 
101

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.

102

Tempered fractional Cauchy problems on bounded domains  

CERN Document Server

Fractional Cauchy problems replace the usual first order time derivative by a fractional derivative. A tempered fractional derivative provides an attractive alternative, and is closely connected to the tempered stable process. This paper develops classical solutions and stochastic analogues for tempered fractional Cauchy problems in a bounded domain $D\\subset \\rd$ with Dirichlet boundary conditions. Stochastic solutions are constructed via an inverse tempered stable subordinator, whose tail index corresponds to the order of the tempered fractional time derivative.

Nane, Erkan; Vellaisamy, Palaniappan

2010-01-01

103

Community Compensatory Trend Prevails from Tropical to Temperate Forest  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Community compensatory trend (CCT) is thought to facilitate persistence of rare species and thus stabilize species composition in tropical forests. However, whether CCT acts over broad geographical ranges is still in question. In this study, we tested for the presence of negative density dependence (NDD) and CCT in three forests along a tropical-temperate gradient. Inventory data were collected from forest communities located in three different latitudinal zones in China. Two widely used meth...

Xiao, Lin; Yu, Shixiao; Li, Mingguang; Wang, Yongfan

2012-01-01

104

Solar ventilation and tempering  

Science.gov (United States)

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.

Adámek, Karel; Pavlů, Miloš; Bandouch, Milan

2014-08-01

105

Phenology of temperate trees in tropical climates.  

Science.gov (United States)

Several North American broad-leaved tree species range from the northern United States at approximately 47 degrees N to moist tropical montane forests in Mexico and Central America at 15-20 degrees N. Along this gradient the average minimum temperatures of the coldest month (T (Jan)), which characterize annual variation in temperature, increase from -10 to 12 degrees C and tree phenology changes from deciduous to leaf-exchanging or evergreen in the southern range with a year-long growing season. Between 30 and 45 degrees N, the time of bud break is highly correlated with T (Jan) and bud break can be reliably predicted for the week in which mean minimum temperature rises to 7 degrees C. Temperature-dependent deciduous phenology-and hence the validity of temperature-driven phenology models-terminates in southern North America near 30 degrees N, where T (Jan)>7 degrees C enables growth of tropical trees and cultivation of frost-sensitive citrus fruits. In tropical climates most temperate broad-leaved species exchange old for new leaves within a few weeks in January-February, i.e., their phenology becomes similar to that of tropical leaf-exchanging species. Leaf buds of the southern ecotypes of these temperate species are therefore not winter-dormant and have no chilling requirement. As in many tropical trees, bud break of Celtis, Quercus and Fagus growing in warm climates is induced in early spring by increasing daylength. In tropical climates vegetative phenology is determined mainly by leaf longevity, seasonal variation in water stress and day length. As water stress during the dry season varies widely with soil water storage, climate-driven models cannot predict tree phenology in the tropics and tropical tree phenology does not constitute a useful indicator of global warming. PMID:15812667

Borchert, Rolf; Robertson, Kevin; Schwartz, Mark D; Williams-Linera, Guadalupe

2005-09-01

106

Evaluation of tropically adapted straightbred and crossbred cattle: postweaning gain and feed efficiency when finished in a temperate climate.  

Science.gov (United States)

Beef cows in the subtropical USA must be adapted to the stressors of the environment, typically supplied by using Brahman (Br) breeding. Calves produced in the region, however, are usually grown and finished in more temperate regions, and have a perceived reputation for poor ADG and feed efficiency during finishing. Compromised fertility and carcass quality often associated with the Br have increased interest in tropically adapted Bos taurus breed types. The objective of this study was to evaluate 3 breeds [An = Angus (Bos taurus, temperate); Br (B. indicus, tropical); and Ro = Romosinuano (B. taurus, tropical)] and all possible crosses during various segments of post-weaning growth, and for feed efficiency during the finishing phase. Steer calves (n = 473) born over 3 yr were weaned in late September, backgrounded for at least 21 d (BKG), shipped 2,025 km to El Reno, OK, in October, fed a preconditioning diet for 28 d (RCV), grazed wheat (Triticum aestivum L.) pasture from November to May (WHT), finished on a conventional feedlot diet (FIN), and serially harvested after approximately 95, 125, and 150 d on feed. Body weight and ADG during each segment were tested using a mixed model that included calf age at weaning, year (Y), breed of sire (SB), breed of dam (DB), and interactions. In addition, winter treatment (continuous wheat or reduced grazing of wheat with supplement) was included for the wheat and feedlot phases. Sire within SB × SB [and pen (barn × year) for feedlot phase] were considered random. The SB × DB interaction was significant for all traits (P weaning and ADG during FIN, but both traits were affected by 3-way interactions with Y or harvest group. Tropically-adapted purebred steers had greater (P weaning and BKG in FL but the reverse was true during the RCV and WHT segments. Similar, but less pronounced results were noted for F(1) steers with 100% tropical influence compared with those with only 50%. Heterosis was numerically greater for most traits for An × Br (11 to 64%) compared with An × Ro and Br × Ro (3 to 42%), which were similar. In a subset of the steers (n = 261), G:F was not influenced by level of tropical breeding, but tropically adapted steers were more efficient (P < 0.05) by residual feed intake. No heterosis was evident. These data show that in temperate zones, winter is the period when productivity of tropically adapted cattle is compromised. PMID:22247114

Coleman, S W; Chase, C C; Phillips, W A; Riley, D G; Olson, T A

2012-06-01

107

Diversity and abundance of photosynthetic sponges in temperate Western Australia  

Directory of Open Access Journals (Sweden)

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.

Brümmer Franz

2009-02-01

108

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)

Full Text Available SciELO Argentina | Language: English Abstract in spanish 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,

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

2010-08-01

109

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

110

Quantity component of the effectiveness of seed dispersal by birds in the temperate rainforest of Chiloé, Chile Componente cuantitativo de la efectividad de dispersión de semillas por aves en el bosque templado de Chiloé, Chile  

Digital Repository Infrastructure Vision for European Research (DRIVER)

The quantity component of the disperser effectiveness of resident birds during the autumn-winter period has not yet been detailed in temperate rainforests of South America. In this study, the potentially frugivorous bird species in the temperate rainforests of southern Chile during the Austral autumn-winter were identified, and the quantity component of the disperser effectiveness of the birds (number of visits and number of seeds dispersed per hour) were evaluated for the tree species Luma a...

Miguel Salvande; Figueroa, Javier A.; Armesto, Juan J.

2011-01-01

111

Protective coating of austenitic steel using robotized GMAW temper-bead technique; Rechargement d'inox austenitique en MAG temperbead robotise  

Energy Technology Data Exchange (ETDEWEB)

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)

Carpreau, J.M. [Electricite de France (EDF/R and D), Recherche et Developpement, 92 - Chatou (France); Dainelli, P. [Institut de Soudure, 57 - Yutz (France)

2009-07-15

112

Mechanical properties and residual stresses in temper bead welded specimens  

Energy Technology Data Exchange (ETDEWEB)

Welding is the principal joining technology used in the fabrication of metallic structures. One of the alternative techniques for post-welded heat treatment(PWHT) is bead tempering during the welding process, where this technique is usually called temper bead welding(TBW). Welding of mild steels and low alloy ferritic steels often requires stress relieving by using PWHT. These heat treatments can be carried out easily during initial fabrication processes. However, PWHT is almost impossible when there are mechanical loads on the structure since it can cause deformation of the structure. In actual effect, the HAZ created by former of three successive beads is tempered by controlling the heat input ratio between three beads(which may also form three weld layers). Also, in recent years considerable effort has been devoted to the development of procedures for incorporating residual stresses in to structural integrity assessments for power plant infrastructure. However, systematic understandings of microstructural changes and mechanical properties as a result of varying in welding sequences and the resulting properties have not been established. The paper particularly investigates the role of the deposition sequence and the spatial deposition of the welding beads in microstructural variation in the critical zones of the resulting weldments such as HAZ, characterising the metallurgical properties, residual stresses, micro hardnesses of such zones.

Kim, Kyeong Ho; Kim, Hong Eun; Lee, Ho Jin; Lee, Bong Sang [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

2009-05-15

113

Diagenetic alterations in temperate shelf carbonates from southeastern Australia  

Science.gov (United States)

Temperate shelf carbonates form in cool marine waters and have skeletal and mineralogical compositions which are different from their tropical counterparts. They commonly lack non-skeletal grains and are often composed of low- and high-magnesium calcite with subordinate aragonite. Many of the aragonitic components found in tropical carbonates, such as corals, ooids, blue-green algae and lime mud, are absent. Temperate shelf carbonates undergo diagenesis in marine waters with lower carbonate saturation than do tropical carbonates, and are exposed to cool climates with moderate to low rainfall. Marine cementation is rare because of low carbonate saturations in the surrounding waters. However, aragonite and high-magnesium calcite cements have been reported forming under specialized conditions associated with biogenic precipitation, submarine methane and sulphate-reducing bacteria, and more commonly in the intertidal environment where evaporation has increased carbonate concentrations. In Pleistocene and Tertiary temperate shelf carbonates from southeastern Australia, evidence of marine diagenesis is rare to absent. Diagenetic stabilization of aragonite and high-magnesium calcite has taken from 80,000 y to 1 My, or longer, during subaerial exposure. This is slower than rates reported from tropical climates. A general lack of aragonite in some facies within these temperate carbonates leads to a lack of secondary porosity and only sparse low-magnesium calcite cement, even after prolonged fresh-water diagenesis. However, with lengthy exposure and under the right climatic conditions, karstic solution and calcrete precipitation can occur. In sequences containing siliciclastic clays, pyrite and glauconite, abundant iron is present in interstitial waters leading to the precipitation of ferroan calcite cements in the phreatic and shallow burial environments, and to the substitution of iron for magnesium in stabilizing high-magnesium calcite skeletal material. A unique void-filling, micritic internal sediment occurs in discrete layers in many of the Tertiary temperate shelf carbonate sequences in southeastern Australia. This internal sediment is localized as a pore-filling material above permeability barriers such as fine-grained sediments or volcanics, and above paleo-water tables which formed during periods of subaerial exposure. It is a feature of the vadose zone and lithifies to form a dense micritic low-magnesium calcite cement with characteristic pink/brown coloration, often associated with erosion surfaces and nodule beds. Dolomite is uncommon in the southeastern Australian temperate shelf carbonates. It forms associated with preferential fluid pathways or mixing zones. Ferroan dolomite forms in siliciclastic clay-rich carbonates in the shallow burial environment. The ubiquitous fine, evaporite-related dolomite so common in tropical carbonates is absent.

Anne Reeckmann, S.

1988-11-01

114

The well-tempered neutralino  

International Nuclear Information System (INIS)

The dark-matter prediction is usually considered as one of the successes of low-energy supersymmetry. We argue that, after LEP constraints are taken into account, the correct prediction for the dark-matter density, at a quantitative level, is no longer a natural consequence of supersymmetry, but it requires special relations among parameters, highly sensitive to small variations. This is analogous to the problem of electroweak-symmetry breaking, where the correct value of the Z mass is obtained only with a certain degree of fine tuning. In the general parameter space of low-energy supersymmetry, one of the most plausible solution to reproduce the correct value of the dark-matter density is the well-tempered neutralino, which corresponds to the boundary between a pure bino and a pure higgsino or wino. We study the properties of well-tempered neutralinos and we propose a simple limit of split supersymmetry that realizes this situation

115

On Fractional Tempered Stable Motion  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Fractional tempered stable motion (fTSm)} is defined and studied. FTSm has the same covariance structure as fractional Brownian motion, while having tails heavier than Gaussian but lighter than stable. Moreover, in short time it is close to fractional stable L\\'evy motion, while it is approximately fractional Brownian motion in long time. A series representation of fTSm is derived and used for simulation and to study some of its sample path properties.

Houdre?, C.; Kawai, R.

2005-01-01

116

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

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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 altitu¬dinal 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 sub¬mediterranean 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 2,368birds 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.

X. Colomé

2010-01-01

117

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

Digital Repository Infrastructure Vision for European Research (DRIVER)

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.

Go?mez-pujol, Llui?s; Forno?s, Joan J.

2010-01-01

118

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

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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 sedimen...

Zbigniew Pruszak; Pham Van Ninh; Marek Szmytkiewicz; Nguyen Manh Hung; Rafa? Ostrowski

2005-01-01

119

Temperature and resource availability may interactively affect over-wintering success of juvenile fish in a changing climate.  

Digital Repository Infrastructure Vision for European Research (DRIVER)

The predicted global warming may affect freshwater systems at several organizational levels, from organism to ecosystem. Specifically, in temperate regions, the projected increase of winter temperatures may have important effects on the over-winter biology of a range of organisms and especially for fish and other ectothermic animals. However, temperature effects on organisms may be directed strongly by resource availability. Here, we investigated whether over-winter loss of biomass and lipid ...

Brodersen, Jakob; Rodriguez-gil, Jose? Luis; Jo?nsson, Mikael; Hansson, Lars-anders; Bro?nmark, Christer; Nilsson, Anders; Nicolle, Alice; Berglund, Olof

2011-01-01

120

PERMEABILITY, WETNESS AND CREEP OF TEMPERATE ICE  

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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...

Lliboutry, L.

1987-01-01

 
 
 
 
121

Laser beam welding tempered 300M ultrahigh mechanical strength steel  

Directory of Open Access Journals (Sweden)

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.

Sheila Medeiros de Carvalho

2012-03-01

122

Laser beam welding tempered 300M ultrahigh mechanical strength steel  

Scientific Electronic Library Online (English)

Full Text Available SciELO Brazil | Language: English Abstract in english 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.

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

2012-03-01

123

Tree-mediated methane emissions from tropical and temperate peatlands.  

Science.gov (United States)

Methane production and transport processes in peatlands are fairly well understood, but growing evidence for emission of methane through trees has highlighted the need to revisit methane transport processes. In wetland trees, morphological adaptations such as development of hypertrophied lenticels, aerenchyma and adventitious roots in response to soil anoxia mediates gas transport, transporting both oxygen from the atmosphere to oxygen-deprived roots and soil-produced methane from the root-zone to the atmosphere. Although, tree-mediated methane emissions from temperate tree species have been confirmed, methane emissions from tropical tree species and processes that control tree-mediated methane emissions remain unclear. This study explains the role of trees in transporting soil-produced methane to the atmosphere and uncovers the principal mechanisms of tree-mediated methane emissions. Methane emissions from eight tropical tree species and two temperate tree species were studied in situ. The mechanisms and controls on tree-mediated methane emissions were investigated using three year old common alder (Alnus glutinosa; 50 trees) grown under two artificially controlled water-table positions. Methane fluxes from whole mesocosms, the soil surface and tree stems were measured using static closed chambers. Both temperate and tropical tree species released significant quantities of methane, with tropical trees dominating ecosystem level methane fluxes. In temperate peatlands, both the methane gas transport mechanism and quantity of methane emitted from stems is tree-species dependent. In Alnus glutinosa, no correlations were observed between stomatal behaviour and tree-mediated methane emissions, however, stem methane emissions were positively correlated with both stem lenticel density and dissolved soil methane concentration. In Alnus glutinosa, no emissions were observed from leaf surfaces. The results demonstrate that exclusion of tree-mediated methane emissions from flux measurement campaigns in forested peatlands will lead to an underestimation of ecosystem-wide methane emissions.

Pangala, S. R.; Gauci, V.; Hornibrook, E. R. C.; Gowing, D. J.

2012-04-01

124

Preventive maintenance technique by temper bead welding for reactor vessel  

International Nuclear Information System (INIS)

Pressurized Water Reactor (PWR) plant has some dissimilar weld joint between main components which are made of Low Alloy Steel and piping which is made of Stainless Steel. Previous plants' dissimilar weld joints are made of Alloy 600 which is low resistance to Primary Water Stress Corrosion Cracking (PWSCC). It is reported that PWSCC is occurred in some plants. The preventive maintenance technique against PWSCC is needed immediately. One solution is the improvement of the material, for example, the inner surface of Alloy 600 is replaced by welding Alloy 690 which is high resistance to PWSCC. Generally, Heat Affected Zone (HAZ) of low alloy steel after welding is required Post Weld Heat Treatment (PWHT), but it is so hard that this operation has to be accomplished in site. So it is necessary to attempt the improvement of HAZ by temper bead welding which isn't needed PWHT. Temper bead welding is that HAZ of 1st weld layer is appropriately covered with heat of after 2nd weld layer, then the mechanical performance of HAZ is improved as well as PWHT. Conventional temper bead welding is required pre-heat and post-heat treatment. However it is impossible to set up the heater due to environment around the dissimilar weld joint in some plants, the development of ambient temperature temper bead welding technique which isn't needed pre-heat and post-heat treatment is expected. It is confirmed that the mechanical performance and the material texture are improved by setting the apial texture are improved by setting the appropriate welding condition with many welding test pieces. Then, the preventive maintenances called INLAY method are completed in some actual plants. (author)

125

Development of temper bead technique applied to dissimilar weld joints of nuclear pressure vessels  

International Nuclear Information System (INIS)

The temper bead technique was developed for the replacement of dissimilar welded joints between stainless steel pipes and low alloy steel nozzles overlaid by nickel base alloy. The heat affected zone of the base metal produced by the first layer weld was refined and tempered by the heat input of the following weld layers with adequate welding conditions. The hardness distributions were equivalent and the Charpy impact properties were superior to those of the postweld heat treated weld after conventional welding. The distributions of residual stresses were also equivalent to those of postweld heat treatment because the materials were dissimilar. This method has passed the verification test of the JAPEIC. (author)

126

Ice-dependent winter survival of juvenile Atlantic salmon  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Changes in snow and ice conditions are some of the most distinctive impacts of global warming in cold temperate and Arctic regions, altering the environment during a critical period for survival for most animals. Laboratories studies have suggested that reduced ice cover may reduce the survival of stream dwelling fishes in Northern environments. This, however, has not been empirically investigated in natural populations in large rivers. Here, we examine how the winter survival of juvenile Atl...

Hedger, R. D.; Næsje, T. F.; Fiske, P.; Ugedal, O.; Finstad, A. G.; Thorstad, E. B.

2013-01-01

127

Stamen development and winter dormancy in apricot (Prunus armeniaca)  

Digital Repository Infrastructure Vision for European Research (DRIVER)

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...

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

2011-01-01

128

Parallel tempering for the traveling salesman problem  

Energy Technology Data Exchange (ETDEWEB)

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.

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

2008-01-01

129

Parallel Tempering for the Traveling Salesman Problem  

Science.gov (United States)

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.

Wang, Chiaming; Hyman, Jeffrey D.; Percus, Allon; Caflisch, Russel

130

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

Science.gov (United States)

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.

Mihai, Bogdan; Savulescu, Ionut

2014-05-01

131

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.

132

Winter Storm Fire Safety  

Science.gov (United States)

... Working with the Media Fire Protection Technology Winter fire safety outreach materials These free materials are yours ... indoors. Outreach materials and messages from the U.S. Fire Administration Winter fire safety infographic Download the infographic ...

133

The interaction between freezing tolerance and phenology in temperate deciduous trees  

Science.gov (United States)

Temperate climates are defined by distinct temperature seasonality with large and often unpredictable weather during any of the four seasons. To thrive in such climates, trees have to withstand a cold winter and the stochastic occurrence of freeze events during any time of the year. The physiological mechanisms trees adopt to escape, avoid, and tolerate freezing temperatures include a cold acclimation in autumn, a dormancy period during winter (leafless in deciduous trees), and the maintenance of a certain freezing tolerance during dehardening in early spring. The change from one phase to the next is mediated by complex interactions between temperature and photoperiod. This review aims at providing an overview of the interplay between phenology of leaves and species-specific freezing resistance. First, we address the long-term evolutionary responses that enabled temperate trees to tolerate certain low temperature extremes. We provide evidence that short term acclimation of freezing resistance plays a crucial role both in dormant and active buds, including re-acclimation to cold conditions following warm spells. This ability declines to almost zero during leaf emergence. Second, we show that the risk that native temperate trees encounter freeze injuries is low and is confined to spring and underline that this risk might be altered by climate warming depending on species-specific phenological responses to environmental cues. PMID:25346748

Vitasse, Yann; Lenz, Armando; Körner, Christian

2014-01-01

134

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

Energy Technology Data Exchange (ETDEWEB)

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.)

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

135

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.)

136

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)

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

OSVALDO J VIDAL

2011-01-01

137

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)

Full Text Available SciELO Chile | Language: English Abstract in spanish 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 fo

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

138

Drilling in tempered glass – modelling and experiments  

DEFF Research Database (Denmark)

The present paper reports experimentally and numerically obtained results for the process of drilling in tempered glass. The experimental results are drilling depths on the edge in 19mm tempered glass with a known residual stress state measured by a scattered light polariscope. The experiments have been modelled using a state-of-the-art model and compared with satisfying result to the performed experiments. The numerical model has been used for a parametric study, investigating the redistribution of residual stresses during the process of drilling. This is done for investigating the possibility of applying forces in such holes and thereby being able to mechanically assemble tempered glass without the need of drilling holes before the tempering process. The paper is the result of currently ongoing research and the results should be treated as so.

Nielsen, Jens Henrik

139

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

140

Effects of seasonal snow on the growing season of temperate vegetation in China.  

Science.gov (United States)

Variations in seasonal snowfall regulate regional and global climatic systems and vegetation growth by changing energy budgets of the lower atmosphere and land surface. We investigated the effects of snow on the start of growing season (SGS) of temperate vegetation in China. Across the entire temperate region in China, the winter snow depth increased at a rate of 0.15 cm yr(-1) (P = 0.07) during the period 1982-1998, and decreased at a rate of 0.36 cm yr(-1) (P = 0.09) during the period 1998-2005. Correspondingly, the SGS advanced at a rate of 0.68 day yr(-1) (P change may be attributed to the coupling effects of air temperature and snow depth associated with the underground thermal conditions. PMID:23532953

Yu, Zhen; Liu, Shirong; Wang, Jingxin; Sun, Pengsen; Liu, Weiguo; Hartley, Damon S

2013-07-01

 
 
 
 
141

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

Science.gov (United States)

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.

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

1995-01-01

142

Variation in Carbon Storage and Its Distribution by Stand Age and Forest Type in Boreal and Temperate Forests in Northeastern China  

Digital Repository Infrastructure Vision for European Research (DRIVER)

The northeastern forest region of China is an important component of total temperate and boreal forests in the northern hemisphere. But how carbon (C) pool size and distribution varies among tree, understory, forest floor and soil components, and across stand ages remains unclear. To address this knowledge gap, we selected three major temperate and two major boreal forest types in northeastern (NE) China. Within both forest zones, we focused on four stand age classes (young, mid-aged, mature ...

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

2013-01-01

143

Temperate origins of long-distance seasonal migration in New World songbirds.  

Science.gov (United States)

Migratory species exhibit seasonal variation in their geographic ranges, often inhabiting geographically and ecologically distinct breeding and nonbreeding areas. The complicated geography of seasonal migration has long posed a challenge for inferring the geographic origins of migratory species as well as evolutionary sequences of change in migratory behavior. To address this challenge, we developed a phylogenetic model of the joint evolution of breeding and nonbreeding (winter) ranges and applied it to the inference of biogeographic history in the emberizoid passerine birds. We found that seasonal migration between breeding ranges in North America and winter ranges in the Neotropics evolved primarily via shifts of winter ranges toward the tropics from ancestral ranges in North America. This result contrasts with a dominant paradigm that hypothesized migration evolving out of the tropics via shifts of the breeding ranges. We also show that major lineages of tropical, sedentary emberizoids are derived from northern, migratory ancestors. In these lineages, the winter ranges served as a biogeographic conduit for temperate-to-tropical colonization: winter-range shifts toward the tropics during the evolution of long-distance migration often preceded southward shifts of breeding ranges, the loss of migration, and in situ tropical diversification. Meanwhile, the evolution of long-distance migration enabled the persistence of old lineages in North America. These results illuminate how the evolution of seasonal migration has contributed to greater niche conservatism among tropical members of this diverse avian radiation. PMID:25092321

Winger, Benjamin M; Barker, F Keith; Ree, Richard H

2014-08-19

144

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

Digital Repository Infrastructure Vision for European Research (DRIVER)

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...

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

2009-01-01

145

The role of seasonal flowering responses in adaptation of grasses to temperate climates  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Grasses of the subfamily Pooideae, including important cereal crops and pasture grasses, are widespread in temperate zones. Seasonal regulation of developmental transitions coordinates the life cycles of Pooideae with the passing seasons so that flowering and seed production coincide with favorable conditions in spring. This review examines the molecular pathways that control the seasonal flowering responses of Pooideae and how variation in the activity of genes controlling these pathways can...

Fjellheim, Siri; Boden, Scott; Trevaskis, Ben

2014-01-01

146

Hydrogen embrittlement susceptibility of tempered 9%Cr-1% Mo steel  

International Nuclear Information System (INIS)

The influence of the subsurface hydrogen activity on the hydrogen embrittlement (HE) susceptibility of a tempered 9%Cr-1%Mo ferritic-martensitic steel (T91) has been studied by constant extension rate tests (CERT) performed under cathodic charging during straining at 20 degrees C. changes in the hydrogen activity on the surface were obtained by varying the cathodic current density imposed during a tensile test completed to fracture. The broken samples were observed by scanning electron microscopy (SEM). The results show a strong dependence of the extent of the brittle zone with the subsurface hydrogen activity. This effect could be attributed to an enhancement of the apparent diffusion coefficient of hydrogen when increasing H activity. Increasing H activity could enhance both the trapping rate on pre-existing and strain-induced traps and H dragging by moving traps such as dislocations. (authors)

147

Winters fuels report  

Energy Technology Data Exchange (ETDEWEB)

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.

NONE

1995-10-27

148

Effect of temper temperature and temper time on stress relaxation of the Cr-Ni-Mo-V steel at reactor vessel fabrication  

International Nuclear Information System (INIS)

The stress relaxation in welded joints of the Cr-Ni-Mo-V steel used for the rings of reactor vessels is investigated. Studies have been made at initial stresses of 20 and 30 kgs/mm2 for the basic metal and of 40 kgs/mm2 for the weld and heat affected zone metal after 2-100 h heat time at 600, 625 and 650 deg C. A conclusion is made that the temper at 625 deg C during 5 hours followed by the temper at the same temperature during 10 hours provides the residual stresses in welded joint not higher than 10% from the yield limit of the steel under investigation

149

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)

Full Text Available SciELO Mexico | Language: Spanish Abstract in spanish 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.

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

2008-08-01

150

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)

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.

Javier Alcocer

2008-08-01

151

Winter Olympic Sports  

Science.gov (United States)

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 ...

Keller, Mrs.

2010-01-23

152

Winter, Your Car, and You  

Science.gov (United States)

... Toggle navigation Public News and Resources – Winter Your Car and You Winter, Your Car and You Start with a checkup that includes: ... a car shut. News and Resources – Winter Your Car and You Get the Facts This page is ...

153

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

154

Evolution of Microsatellite Loci of Tropical and Temperate Anguilla Eels  

Digital Repository Infrastructure Vision for European Research (DRIVER)

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 tot...

Mei-Chen Tseng

2012-01-01

155

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

DEFF Research Database (Denmark)

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.

Andresen, Louise C.; Michelsen, Anders

2010-01-01

156

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

157

Humidity and respiratory virus transmission in tropical and temperate settings.  

Science.gov (United States)

SUMMARY Influenza and respiratory syncytial virus (RSV) are similarly structured viruses with similar environmental survival, but different routes of transmission. While RSV is transmitted predominantly by direct and indirect contact, influenza is also transmitted by aerosol. The cold, dry conditions of temperate winters appear to encourage the transmission of both viruses, by increasing influenza virus survival in aerosols, and increasing influenza and RSV survival on surfaces. In contrast, the hot, wet conditions of tropical rainy seasons appear to discourage aerosol transmission of influenza, by reducing the amount of influenza virus that is aerosolized, and probably also by reducing influenza survival in aerosol. The wet conditions of tropical rainy seasons may, however, encourage contact transmission of both viruses, by increasing the amount of virus that is deposited on surfaces, and by increasing virus survival in droplets on surfaces. This evidence suggests that the increased incidence of influenza and RSV in tropical rainy seasons may be due to increased contact transmission. This hypothesis is consistent with the observation that tropical rainy seasons appear to encourage the transmission of RSV more than influenza. More research is required to examine the environmental survival of respiratory viruses in the high humidity and temperature of the tropics. PMID:25307020

Paynter, S

2014-10-13

158

A Facies Model for Temperate Continental Glaciers.  

Science.gov (United States)

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)

Ashley, Gail Mowry

1987-01-01

159

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)

160

Fluxes of H2, COS, and CO2 across a temperate forest snowpack driven by below snow soil microbial processes  

Science.gov (United States)

Snowpack overlying temperate soils insulates soil microbial communities from wintertime subzero air temperatures that would otherwise halt most biogeochemical processes. Moreover, a porous snow matrix permits soil-atmosphere trace gas exchange to continue despite the snowpack cover. Consequently, below snow (subniveal) soil biogeochemical processes proceed throughout the winter season and continue to impact atmospheric trace gas composition. In this study, three atmospheric trace gases (H2, COS, CO2) that exhibit strong soil-atmosphere exchange are investigated to understand the following: 1) how snowpack properties affect the exchange of trace gases and 2) how different biogeochemical cycles behave throughout the low temperature subniveal winter. The selected trace gases represent largely decoupled and distinct biogeochemical cycles. Soil microorganisms act as a net sink for atmospheric hydrogen (H2) and carbonyl sulfide (COS) by oxidation (hydrogenase) and hydrolysis (carbonic anhydrase) reactions, respectively. In contrast, soil microbial respiration is a strong source of atmospheric carbon dioxide (CO2). We present continuous, high frequency atmospheric flux measurements of H2, COS, and CO2 over the winter season in a temperate deciduous forest. Significant soil-atmosphere trace gas exchange was measured above the four-month snowpack, which reached 70 cm at peak accumulation. Additionally, we use a novel camera-based method to monitor snow depth, density, and fractional extent to understand how physical snowpack properties affect the exchange of these trace gases. The episodic nature of snow fall, snow melt, and snowpack ventilation events are also considered. By comparative analysis of the H2, COS, and CO2 fluxes, we investigate differences in subniveal biogeochemical processes at different soil temperature and moisture levels throughout the winter season. Projections for global change anticipate changes in the temperate snowpack; therefore, understanding the processes by which the snowpack influences soil-atmosphere exchange of a variety of trace gases is crucial.

Meredith, L. K.; McLaren, J.; Commane, R.; Munger, J. W.; Prinn, R. G.; Wofsy, S. C.; Richardson, A. D.

2011-12-01

 
 
 
 
161

[Pteridophytes that indicate environmental alteration in the temperate forest of San Jerónimo Amanalco, Texcoco, Mexico].  

Science.gov (United States)

Pteridophytes that indicate environmental alteration in the San Jer6nimo Amanalco temperate forest, Texcoco, Mexico. The patterns of distribution of 26 pteridophyte species were studied as possible indicators of environmental alteration in the temperate forest of San Jer6nimo Amanalco, Texcoco, State of Mexico. The presence and abundance of the pteridoflora was studied in relation to edaphic, topographic and vegetation variables in 100 sampling locations within an area of 494 hectares. The relationship between these variables was studied using Canonical Correspondence Analysis. Five landscapes were recognized in the study zone according to the degree of deterioration: severe erosion, erosion, mountain with moderate reversible deterioration, mountain with no evident deterioration, and canyon with no evident deterioration. Cheilanthes bonariensis and Pellaea ternifolia are indicators of environmental degradation. The taxa that only grow in landscapes without apparent alteration are Adiantum andicola, Adiantum poiretii, Argyrochosma incana, Asplenium blepharophorum, Dryopteris pseudo filix-mas, Equisetum hyemale and Pteris cretica. PMID:19256434

Lucía Rodríguez, Romero; Pacheco, Leticia; Zavala Hurtado, José Alejandro

2008-06-01

162

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.

163

Simulation of over-winter soil water and soil temperature with SHAW and RZ-SHAW  

Science.gov (United States)

Correct simulation of over-winter condition is important for the growth of winter crops and for initial growth of spring crops. RZ-SHAW (RZWQM-SHAW) is a newly developed model by coupling the Root Zone Water Quality Model (RZWQM) and the Simultaneous Heat and Water (SHAW) model. The objective of thi...

164

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

Directory of Open Access Journals (Sweden)

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.

Zbigniew Pruszak

2005-09-01

165

Parallel Excluded Volume Tempering for Polymer Melts  

CERN Document Server

We have developed a technique to accelerate the acquisition of effectively uncorrelated configurations for off-lattice models of dense polymer melts which makes use of both parallel tempering and large scale Monte Carlo moves. The method is based upon simulating a set of systems in parallel, each of which has a slightly different repulsive core potential, such that a thermodynamic path from full excluded volume to an ideal gas of random walks is generated. While each system is run with standard stochastic dynamics, resulting in an NVT ensemble, we implement the parallel tempering through stochastic swaps between the configurations of adjacent potentials, and the large scale Monte Carlo moves through attempted pivot and translation moves which reach a realistic acceptance probability as the limit of the ideal gas of random walks is approached. Compared to pure stochastic dynamics, this results in an increased efficiency even for a system of chains as short as $N = 60$ monomers, however at this chain length the...

Bunker, A J; Bunker, Alex; Duenweg, Burkhard

2000-01-01

166

Initiation of winter phytoplankton blooms within the Gironde plume waters in the Bay of Biscay  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Thermostratification and seasonal Light increase are generally considered the first causes of phytoplankton spring blooms in temperate waters. The objective of this study is to confirm the existence of winter phytoplankton blooms, responsible for the early exhaustion of phosphate, within the Gironde plume waters (southeast Bay of Biscay), and to understand what may initiate them so early. Two cruises, BIOMET 2 and BIOMET 3, were carried out respectively in early (8 to 21 January) and late win...

Labry, Claire; Herbland, Alain; Delmas, Daniel; Laborde, P.; Lazure, Pascal; Froidefond, J.; Jegou, Anne-marie; Sautour, B.

2001-01-01

167

Lightweight dividing walls : adaptation to temperate climates  

Digital Repository Infrastructure Vision for European Research (DRIVER)

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...

Mendonc?a, Paulo; Macieira, Mo?nica

2011-01-01

168

Predicting habitat suitability in temperate seagrass ecosystems  

Digital Repository Infrastructure Vision for European Research (DRIVER)

The worldwide observed dramatic decline of seagrasses has typically been attributed to multiple stressors such as eutrophication, disease, sedimentation, and toxicity events. Using principal component analysis and (multivariate) logistic regression, we investigated the importance of 30 commonly measured variables in explaining the presence and absence of the temperate seagrass species Zostera marina and Zostera noltii at 84 Western European locations. Although many interrelated variables infl...

Heide, Tj; Peeters, E. T. H. M.; Hermus, D. C. R.; Katwijk, M. M.; Roelofs, J. G. M.; Smolders, A. J. P.

2009-01-01

169

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

Science.gov (United States)

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

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

2011-07-01

170

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)

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.

I. Vitela

2005-01-01

171

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  

Scientific Electronic Library Online (English)

Full Text Available SciELO Chile | Language: Spanish Abstract in spanish 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. Abstract in english 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 Aguasca [...] lientes. 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.

I., Vitela; C., Cruz-Vázquez; J., Solano.

172

The macroalgal carbonate factory at a cool-to-warm temperate marine transition, Southern Australia  

Science.gov (United States)

The shallow neritic seafloor to depths of ~ 30 m along the coast of southwestern Victoria Australia, is the site of rocky reefs on volcanic and aeolianite bathymetric highs. The region, located near the warm- to cool-temperate environmental transition, is a site of prolific macroalgae (kelp) growth. Kelps are most prolific and diverse in high-energy, open-ocean environments whereas broad-leafed seagrasses, at their cold-water eastern limit, are restricted to local protected embayments. The seagrasses are reduced to one species of Amphibolis whereas the kelps are diverse and include the large intertidal bull kelp (Durvillaea), not present in warmer waters. The macroalgal forest extends from the intertidal to ~ 30 mwd (metres water depth) as a series of distinct biomes; 1) the Peritidal, 2) the Phaeophyte Forest (0-17 mwd), 3) the Rhodophyte Thicket (17-15 mwd), and 4) the Invertebrate Coppice (> 25 mwd). The Phaeophyte Forest is partitioned into a Durvillaea zone (0-2 mwd), a Phyllospora zone (2-10 mwd) and an Ecklonia zone (10-17mwd). The two major habitats within each biome comprise 1) an upward facing illuminated surface that supports a macroalgal canopy over an understorey of coralline algae and herbivorous gastropods, and 2) a separate, cryptic, shaded habitat dominated by a diverse community of filter-feeding invertebrates. These communities produce two different sediments; 1) geniculate and encrusting corallines and diverse gastropods from the upper surface, and 2) bryozoans, molluscs, barnacles, chitons, serpulids, and benthic foraminifers from the shaded, cryptic habitats. These particles are blended together with the latter becoming proportionally more abundant with increasing depth. Results of this study, when integrated with recent investigations in warm-temperate (South Australia) and cool-temperate (New Zealand) environments now define carbonate sedimentology of the macroalgal reef depositional system in this part of the northern Southern Ocean.

James, Noel P.; Reid, Catherine M.; Bone, Yvonne; Levings, Andrew; Malcolm, Isabelle

2013-06-01

173

Analysis of grain characters in temperate grasses reveals distinctive patterns of endosperm organization associated with grain shape  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Members of the core pooids represent the most important crops in temperate zones including wheat, barley, and oats. Their importance as crops is largely due to the grain, particularly the storage capabilities of the endosperm. In this study, a comprehensive survey of grain morphology and endosperm organization in representatives of wild and cultivated species throughout the core pooids was performed. As sister to the core pooid tribes Poeae, Aveneae, Triticeae, and Bromeae within the Pooideae...

Hands, Philip; Kourmpetli, Sofia; Sharples, Donna; Harris, Robert G.; Drea, Sine?ad

2012-01-01

174

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

Digital Repository Infrastructure Vision for European Research (DRIVER)

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 ...

Roberto Bertoni; Cristiana Callieri; Salvador Hernandez-aviles, J.; Miroslav Macek

2012-01-01

175

Tempered fundamental group and metric graph of a Mumford curve  

CERN Document Server

This paper is an attempt to give some general results on the tempered fundamental group of a $p$-adic smooth algebraic varieties (which is a sort of analog of the topologic fundamental group of complex algebraic varieties in the p-adic world). The main result asserts that one can recover the metric structure of the graph of the stable model of a Mumford curve from the tempered fundamental group of this Mumford curve. We will also prove birational invariance, invariance by algebraically closed extensions and a Kuenneth formula for the tempered fundamental group. We will describe the tempered fundamental group of an abelian variety and link the tempered fundamental group of a curve to the tempered fundamental group of its Jacobian variety.

Lepage, Emmanuel

2008-01-01

176

In vitro Anti-Malarial Drug Susceptibility of Temperate Plasmodium vivax from Central China  

Digital Repository Infrastructure Vision for European Research (DRIVER)

In the face of recent increase of Plasmodium vivax malaria in central China, we conducted a study to evaluate in vitro susceptibility of temperate-zone P. vivax parasites to antimalarial drugs. During 2005–2006, in vitro drug susceptibility was measured for 42 clinical P. vivax isolates by using a schizont maturation inhibition technique. Geometric means of 50% inhibitory concentrations (IC50s) and 95% confidence intervals (CIs) were 10.87 (4.50–26.26) ng/mL for chloroquine, 4.21 (1.88–...

Lu, Feng; Gao, Qi; Chotivanich, Kesinee; Xia, Hui; Cao, Jun; Udomsangpetch, Rachanee; Cui, Liwang; Sattabongkot, Jetsumon

2011-01-01

177

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

Digital Repository Infrastructure Vision for European Research (DRIVER)

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...

Hansson, Per

2004-01-01

178

Excess Winter Mortality and Cold Temperatures in a Subtropical City, Guangzhou, China  

Science.gov (United States)

Background A significant increase in mortality was observed during cold winters in many temperate regions. However, there is a lack of evidence from tropical and subtropical regions, and the influence of ambient temperatures on seasonal variation of mortality was not well documented. Methods This study included 213,737 registered deaths from January 2003 to December 2011 in Guangzhou, a subtropical city in Southern China. Excess winter mortality was calculated by the excess percentage of monthly mortality in winters over that of non-winter months. A generalized linear model with a quasi-Poisson distribution was applied to analyze the association between monthly mean temperature and mortality, after controlling for other meteorological measures and air pollution. Results The mortality rate in the winter was 26% higher than the average rate in other seasons. On average, there were 1,848 excess winter deaths annually, with around half (52%) from cardiovascular diseases and a quarter (24%) from respiratory diseases. Excess winter mortality was higher in the elderly, females and those with low education level than the young, males and those with high education level, respectively. A much larger winter increase was observed in out-of-hospital mortality compared to in-hospital mortality (45% vs. 17%). We found a significant negative correlation of annual excess winter mortality with average winter temperature (rs=-0.738, P=0.037), but not with air pollution levels. A 1 °C decrease in monthly mean temperature was associated with an increase of 1.38% (95%CI:0.34%-2.40%) and 0.88% (95%CI:0.11%-1.64%) in monthly mortality at lags of 0-1 month, respectively. Conclusion Similar to temperate regions, a subtropical city Guangzhou showed a clear seasonal pattern in mortality, with a sharper spike in winter. Our results highlight the role of cold temperature on the winter mortality even in warm climate. Precautionary measures should be strengthened to mitigate cold-related mortality for people living in warm climate. PMID:24116214

Yang, Jun; Chau, Patsy Yuen-Kwan; Yang, Lin; Chen, Ping-Yan; Wong, Chit-Ming

2013-01-01

179

Enhanced Sampling in the Well-Tempered Ensemble  

Digital Repository Infrastructure Vision for European Research (DRIVER)

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 ar...

Bonomi, M.; Parrinello, M.

2009-01-01

180

Root diameter variations explained by anatomy and phylogeny of 50 tropical and temperate tree species.  

Science.gov (United States)

Root diameter, a critical indicator of root physiological function, varies greatly among tree species, but the underlying mechanism of this high variability is unclear. Here, we sampled 50 tree species across tropical and temperate zones in China, and measured root morphological and anatomical traits along the first five branch orders in each species. Our objectives were (i) to reveal the relationships between root diameter, cortical thickness and stele diameter among tree species in tropical and temperate forests, and (ii) to investigate the relationship of both root morphological and anatomical traits with divergence time during species radiation. The results showed that root diameter was strongly affected by cortical thickness but less by stele diameter in both tropical and temperate species. Changes in cortical thickness explained over 90% of variation in root diameter for the first order, and ?74-87% for the second and third orders. Thicker roots displayed greater cortical thickness and more cortical cell layers than thinner roots. Phylogenetic analysis demonstrated that root diameter, cortical thickness and number of cortical cell layers significantly correlated with divergence time at the family level, showing similar variation trends in geological time. The results also suggested that trees tend to decrease their root cortical thickness rather than stele diameter during species radiation. The close linkage of variations in root morphology and anatomy to phylogeny as demonstrated by the data from the 50 tree species should provide some insights into the mechanism of root diameter variability among tree species. PMID:24695727

Gu, Jiacun; Xu, Yang; Dong, Xueyun; Wang, Hongfeng; Wang, Zhengquan

2014-04-01

 
 
 
 
181

Some Properties of Saturn'ian Equatorialand Temperate Belts at the 2009 Equinox  

Science.gov (United States)

The special processing was made for more than 600 zonal spectra obtained by scanning of Saturn’s disk during the equinox-2009. A comparative study of the optical characteristics of the southern and northern temperate latitudes and equatorial belt have shown some hemispheric differences in the methane absorption behavior. In the equatorial zone we have usually observed decrease in the intensity of the methane absorption compared to temperate latitudes. But the correct estimation of this difference may be done only at the equinox when the ting influence is minimal. In 2009 the methane absorption on equator leas 21-24 per cent less than on temperate latitudes and it may considered as true value of that difference. The CH4 absorption bands variations at middle latitudes show some of the specific features. In particular, the absorption band of 725 nm in the southern hemisphere is not different from that in the northern hemisphere. However, other bands, centered at 619, 678, 702 and 787 nm, ate some less in the S- hemisphere than in the N-hemisphere. This difference grows with the bands weakening. During the preceding equinox in 1995 similar asymmetry was expressed more strongly and also with the absorption depression at southern hemisphere. These differences are considered as related to the vertical inhomogeneity of the cloud layer, increased the upper boundary of the clouds in the equatorial belt, and seasonal changes in the radiation regime hemispheres of Saturn. The results of this work will be published in «Solar System Research».

Tejfel, Victor G.; Karimov, Alibek M.; Kharitonova, Galina A.

2014-11-01

182

WINTER, Interactive WIMS Input Preparation  

International Nuclear Information System (INIS)

1 - Description of program or function: The WINTER code permits interactive preparation of different WIMS input data. 2 - Restrictions on the complexity of the problem: There are a few WIMS input keywords not included in WINTER, (see the User's Manual)

183

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

Digital Repository Infrastructure Vision for European Research (DRIVER)

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 ...

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

2011-01-01

184

Influenza, Winter Olympiad, 2002  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Prospective surveillance for influenza was performed during the 2002 Salt Lake City Winter Olympics. Oseltamivir was administered to patients with influenzalike illness and confirmed influenza, while their close contacts were given oseltamivir prophylactically. Influenza A/B was diagnosed in 36 of 188 patients, including 13 athletes. Prompt management limited the spread of this outbreak.

Gundlapalli, Adi V.; Rubin, Michael A.; Samore, Matthew H.; Lopansri, Bert; Lahey, Timothy; Mcguire, Heather L.; Winthrop, Kevin L.; Dunn, James J.; Willick, Stuart E.; Vosters, Randal L.; Waeckerle, Joseph F.; Carroll, Karen C.; Gwaltney, Jack M.; Hayden, Frederick G.; Elstad, Mark R.

2006-01-01

185

Influenza-associated mortality in temperate and subtropical chinese cities, 2003-2008 / Mortalité associée à la grippe dans les villes des zones tempérées et subtropicales de Chine, 2003-2008 / La mortalidad asociada a la gripe en ciudades chinas con clima templado y subtropical, 2003-2008  

Scientific Electronic Library Online (English)

Full Text Available SciELO Public Health | Language: English Abstract in spanish OBJETIVO: Calcular la mortalidad asociada a la gripe en la China urbana. MÉTODOS: Se calculó el exceso de mortalidad asociado a la gripe durante el periodo comprendido entre 2003 y 2008 en tres ciudades del norte de China con clima templado y en cinco ciudades del sur del país con clima subtropical. [...] Los cálculos se obtuvieron de modelos basados en regresiones binomiales negativas, estadísticas vitales y de los resultados de la vigilancia semanal del virus de la gripe. RESULTADOS: El exceso de mortalidad anual asociado a la gripe, por todas las causas, fue de 18,0 (rango: 10,9-32,7) muertes por cada 100000 habitantes en las ciudades del norte y de 11,3 (rango: 7,3-17,8) muertes por cada 100000 habitantes en las ciudades del sur. La mayor parte de este exceso de mortalidad - 12,4 (rango: 7,4-22,2) y 8,8 (rango: 5,5-13,6) muertes por cada 100000 habitantes en las ciudades del norte y del sur, respectivamente - se atribuyeron a una enfermedad respiratoria y/o circulatoria. La mayoría de las muertes (el 86%) ocurrió en personas con una edad >65 años. El exceso de mortalidad asociado a la gripe fue superior en épocas con un virus B dominante que en épocas en las que predominaron los virus A(H3N2) o A(H1N1). Más de la mitad de la mortalidad total asociada a la gripe se asoció al virus B de la gripe. CONCLUSIÓN: Entre 2003 y 2008, la gripe estacional, particularmente la causada por el virus B de la gripe, estuvo asociada a la mortalidad sustancial en tres ciudades de China con clima templado y en cinco ciudades del sur del país con clima subtropical. Abstract in english OBJECTIVE: To estimate influenza-associated mortality in urban China. METHODS: Influenza-associated excess mortality for the period 2003-2008 was estimated in three cities in temperate northern China and five cities in the subtropical south of the country. The estimates were derived from models base [...] d on negative binomial regressions, vital statistics and the results of weekly influenza virus surveillance. FINDINGS: Annual influenza-associated excess mortality, for all causes, was 18.0 (range: 10.9-32.7) deaths per 100000 population in the northern cities and 11.3 (range: 7.3-17.8) deaths per 100000 in the southern cities. Excess mortality for respiratory and circulatory disease was 12.4 (range: 7.4-22.2) and 8.8 (range: 5.5-13.6) deaths per 100000 people in the northern and southern cities, respectively. Most (86%) deaths occurred among people aged >65 years. Influenza-associated excess mortality was higher in B-virus-dominant seasons than in seasons when A(H3N2) or A(H1N1) predominated, and more than half of all influenza-associated mortality was associated with influenza B virus. CONCLUSION: Between 2003 and 2008, seasonal influenza, particularly that caused by the influenza B virus, was associated with substantial mortality in three cities in the temperate north of China and five cities in the subtropical south of the country.

Luzhao, Feng; David K, Shay; Yong, Jiang; Hong, Zhou; Xin, Chen; Yingdong, Zheng; Lili, Jiang; Qingjun, Zhang; Hong, Lin; Shaojie, Wang; Yanyan, Ying; Yanjun, Xu; Nanda, Wang; Zijian, Feng; Cecile, Viboud; Weizhong, Yang; Hongjie, Yu.

2012-04-01

186

Winter Wilderness Travel and Camping.  

Science.gov (United States)

Knowledge and skill are needed for safe and enjoyable travel and camping in the wilderness in winter. The beauty of snow and ice, reduced human use, and higher tolerance of animals toward humans make the wilderness attractive during winter. The uniqueness of winter travel presents several challenges that are not present in other seasons. Safety is…

Gilchrest, Norman

187

Myxomycetes associated with pipevine, a temperate liana  

Directory of Open Access Journals (Sweden)

Full Text Available Pinevine (Aristolochia macrophylla Lam., a climbing woody vine native to temperate forests of eastern North America, is morphologically similar to many of the lianas characteristic of moist tropical forests. In August 2010, samples of dead pinevine collected from a study site in the Great Smoky Mountains National Park were used to prepare a series of 50 moist chamber cultures. Thirty-seven of the 50 cultures (74% yielded evidence (either plasmodia or fruiting bodies of myxomycetes. Fourteen species representing seven genera were recorded, with members of the Trichiales (41% of all records and Physarales (49% of all records the most abundant.

Coelho IL

2012-04-01

188

Robust Parameter Selection for Parallel Tempering  

CERN Document Server

This paper describes an algorithm for selecting parameter values (e.g. temperature values) at which to measure equilibrium properties with Parallel Tempering Monte Carlo simulation. Simple approaches to choosing parameter values can lead to poor equilibration of the simulation, especially for Ising spin systems that undergo $1^st$-order phase transitions. However, starting from an initial set of parameter values, the careful, iterative respacing of these values based on results with the previous set of values greatly improves equilibration. Example spin systems presented here appear in the context of Quantum Monte Carlo.

Hamze, Firas; Karimi, Kamran

2010-01-01

189

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.

190

A case of congenital plasmodium vivax malaria from a temperate region in central china  

Directory of Open Access Journals (Sweden)

Full Text Available Abstract In February 2011, a rare case of congenital Plasmodium vivax malaria was diagnosed in a temperate region of Central China. An infant developed intermittent fever 20?days after delivery. Since this occurred during the non-transmission winter season in a low malaria endemic region and the infant’s mother did not have a clear malaria history or showed malaria symptoms at the time of the delivery, malaria infection was not suspected at the beginning. Later, on suspicion of potential malignant haematological illness due to persistence of the fever, bone marrow smear was examined, which revealed infection by P. vivax parasite. This rare case of congenital vivax malaria underlines that malaria diagnosis might need to be included in the healthcare of neonates born in vivax-endemic areas.

Liu Xue

2012-06-01

191

Editorial - The winter Atomiades  

CERN Multimedia

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...

Staff Association

2011-01-01

192

Winter maintenance and cycleways  

Digital Repository Infrastructure Vision for European Research (DRIVER)

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...

Bergstro?m, Anna

2002-01-01

193

Importance of mixotrophic nanoplankton in Aysén Fjord (Southern Chile) during austral winter  

Science.gov (United States)

Mixotrophy, the combination of autotrophic and heterotrophic nutrition in the same organism, is widespread in planktonic algae. Several reports from temperate and high-latitude fjords in Scandinavia suggest the occurrence of a niche in late summer and autumn during post-bloom conditions in which mixotrophic algae can become important grazers in pelagic ecosystems, accessing the nutrients bound in their prey to overcome nutrient limitation. Here, we experimentally determined the trophic modes and bacterivory rates for the nanoplankton community (2-20 ?m) in Aysén Fjord located in the Chilean Northern Patagonia during two contrasting seasons: winter and spring. While mixotrophic nanoplankton was virtually absent from the system in spring, in winter at occasions it even constituted the dominant trophic group of the nanoplankton with abundances of >900 cells mL -1. This indicates a second niche for mixotrophs in winter, when mixotrophy allows overcoming light limitation.

Czypionka, Till; Vargas, Cristian A.; Silva, Nelson; Daneri, Giovanni; González, Humberto E.; Iriarte, José Luis

2011-03-01

194

Quantifying Uncertainty in Estimation of Potential Recharge in Tropical and Temperate Catchments using a Crop Model and Microwave Remote Sensing  

Science.gov (United States)

Groundwater recharge in a semi-arid region is generally low, but could exhibit high spatial variability depending on the soil type and plant cover. The potential recharge (the drainage flux just beneath the root zone) is found to be sensitive to water holding capacity and rooting depth (Rushton, 2003). Simple water balance approaches for recharge estimation often fail to consider the effect of plant cover, growth phases and rooting depth. Hence a crop model based approach might be better suited to assess sensitivity of recharge for various crop-soil combinations in agricultural catchments. Martinez et al. (2009) using a root zone modelling approach to estimate groundwater recharge stressed that future studies should focus on quantifying the uncertainty in recharge estimates due to uncertainty in soil water parameters such as soil layers, field capacity, rooting depth etc. Uncertainty in the parameters may arise due to the uncertainties in retrieved variables (surface soil moisture and leaf area index) from satellite. Hence a good estimate of parameters as well as their uncertainty is essential for a reliable estimate of the potential recharge. In this study we focus on assessing the sensitivity of crop and soil types on the potential recharge by using a generic crop model STICS. The effect of uncertainty in the soil parameters on the estimates of recharge and its uncertainty is investigated. The multi-layer soil water parameters and their uncertainty is estimated by inversion of STICS model using the GLUE approach. Surface soil moisture and LAI either retrieved from microwave remote sensing data or measured in field plots (Sreelash et al., 2012) were found to provide good estimates of the soil water properties and therefore both these data sets were used in this study to estimate the parameters and the potential recharge for a combination of soil-crop systems. These investigations were made in two field experimental catchments. The first one is in the tropical semi-arid region of South India (AMBHAS research observatory), wherein the recharge occurs mainly during the crop growth period and Indian summer monsoon (June-November). The second catchment is in the temperate climate region of South-east of France (Avignon), wherein recharge occurs during the winter when crop growth is minimal. The effect of parameter uncertainty on the potential recharge and its uncertainty is compared in these contrasting catchments. References Martinez, J.J., Skaggs, T.H., van Genuchten, M. Th. and Candela, L. (2009). A root zone modelling approach to estimating groundwater recharge from irrigated areas. Journal of Hydrology, 367,138-149 Rushton, K. R. (2003). Groundwater Hydrology. Conceptual and computational models, John Wiley, 416 p. Sreelash, K., Sekhar, M., Ruiz, L., Tomer, S. K., Guérif, M., Buis, S., Durand, P., and Gascuel-Odoux, C. (2012). Parameter estimation of a two-horizon soil profile by combining crop canopy and surface soil moisture observations using GLUE, Journal of Hydrology, 456-457, pp.57-67.

Krishnan Kutty, S.; Sekhar, M.; Ruiz, L.; Tomer, S. K.; Bandyopadhyay, S.; Buis, S.; Guerif, M.; Gascuel-odoux, C.

2012-12-01

195

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

Science.gov (United States)

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 ppt of dicarbonyls observed, corresponding to 11 and 17% of the observed glyoxal and 28 and 10% of the methylglyoxal at Chatham Rise and Cape Grim, respectively, highlighting a significant but as yet unknown production mechanism. Glyoxal surface 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 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.

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

2014-08-01

196

Forecasting cyanobacteria dominance in Canadian temperate lakes.  

Science.gov (United States)

Predictive models based on broad scale, spatial surveys typically identify nutrients and climate as the most important predictors of cyanobacteria abundance; however these models generally have low predictive power because at smaller geographic scales numerous other factors may be equally or more important. At the lake level, for example, the ability to forecast cyanobacteria dominance is of tremendous value to lake managers as they can use such models to communicate exposure risks associated with recreational and drinking water use, and possible exposure to algal toxins, in advance of bloom occurrence. We used detailed algal, limnological and meteorological data from two temperate lakes in south-central Ontario, Canada to determine the factors that are closely linked to cyanobacteria dominance, and to develop easy to use models to forecast cyanobacteria biovolume. For Brandy Lake (BL), the strongest and most parsimonious model for forecasting % cyanobacteria biovolume (% CB) included water column stability, hypolimnetic TP, and % cyanobacteria biovolume two weeks prior. For Three Mile Lake (TML), the best model for forecasting % CB included water column stability, hypolimnetic TP concentration, and 7-d mean wind speed. The models for forecasting % CB in BL and TML are fundamentally different in their lag periods (BL = lag 1 model and TML = lag 2 model) and in some predictor variables despite the close proximity of the study lakes. We speculate that three main factors (nutrient concentrations, water transparency and lake morphometry) may have contributed to differences in the models developed, and may account for variation observed in models derived from large spatial surveys. Our results illustrate that while forecast models can be developed to determine when cyanobacteria will dominate within two temperate lakes, the models require detailed, lake-specific calibration to be effective as risk-management tools. PMID:25585147

Persaud, Anurani D; Paterson, Andrew M; Dillon, Peter J; Winter, Jennifer G; Palmer, Michelle; Somers, Keith M

2015-03-15

197

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

DEFF Research Database (Denmark)

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.

Nielsen, Jens Henrik

2013-01-01

198

46 CFR 42.30-10 - Southern Winter Seasonal Zone.  

Science.gov (United States)

...S., longitude 118° E.; thence the rhumb line to Cape Grim on the northwest coast of Tasmania; thence along the north and east coasts of Tasmania to the southernmost point of Bruny Island; thence the rhumb line to Black Rock Point...

2010-10-01

199

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

Digital Repository Infrastructure Vision for European Research (DRIVER)

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...

Mitrovski, P.; Hoffmann, A. A.

2001-01-01

200

Measurements for winter road maintenance  

Digital Repository Infrastructure Vision for European Research (DRIVER)

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...

Riehm, Mats

2012-01-01

 
 
 
 
201

Chaffinch and Winter Wren  

Science.gov (United States)

Every morning when he walks the dog, retired professor of natural history Peter Slater can identify as many as thirty birds by their song alone. On a walk in a Scottish town with Ari Daniel Shapiro, Slater explains what two common songsters, the chaffinch and winter wren, are singing about, and how even city dwellers can learn to âbird by earâ in their own neighborhoods, with rewarding results. Also included is a Learn More section that provides background information on the scientists recorded in the podcast, lessons, images, and cool facts.

2009-01-01

202

Ensemble Applications in Winter  

Science.gov (United States)

This lesson provides an introduction to ensemble forecast systems using an operational case study of the Blizzard of 2013 in Southern Ontario. The module uses models available to forecasters in the Meteorological Service of Canada, including Canadian and U.S. global and regional ensembles. After briefly discussing the rationale for ensemble forecasting, the module presents small lessons on probabilistic ensemble products useful in winter weather forecasting, immediately followed by forecast applications to a southern Ontario case. The learner makes forecasts for the Ontario Storm Prediction Center area and, in the short range, for the Toronto metropolitan area. An additional section applies a probabilistic aviation product to forecasts for Toronto Pearson International Airport.

Comet

2014-04-22

203

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

Science.gov (United States)

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.

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

2014-04-01

204

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.

205

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.

206

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)

207

Diffusion and relaxation controlled by tempered alpha-stable processes.  

Science.gov (United States)

We derive general properties of anomalous diffusion and nonexponential relaxation from the theory of tempered alpha-stable processes. The tempering results in the existence of all moments of operational time. The subordination by the inverse tempered alpha-stable process provides diffusion (relaxation) that occupies an intermediate place between subdiffusion (Cole-Cole law) and normal diffusion (exponential law). Here we obtain explicitly the Fokker-Planck equation and the Cole-Davidson relaxation function. This model includes subdiffusion as a particular case. PMID:19113094

Stanislavsky, Aleksander; Weron, Karina; Weron, Aleksander

2008-11-01

208

Ductile-Brittle Transition Behavior in Tempered Martensitic SA508 Gr. 4N Ni-Mo-Cr Low Alloy Steels for Reactor Pressure Vessels  

International Nuclear Information System (INIS)

Reactor pressure vessels (RPVs) operate under severe conditions of elevated temperature, high pressure, and irradiation. Therefore, a combination of sufficient strength, toughness, good weldability, and high irradiation resistance are required for RPV materials. SA508 Gr.4N low alloy steel, which has higher Ni and Cr contents than those of commercial RPV steel, Gr.3 steel, is considered as a candidate material due to its excellent mechanical properties from tempered martensitic microstructure. The ferritic steels such as Gr.3 and Gr.4N low alloy steels reveal a ductile-brittle transition and large scatters in the fracture toughness within a small temperature range. Recently, there are some observations of the steeper transition behavior in the tempered martensitic steels, such as Eurofer97 than the transition behavior of commercial RPV steels. It was also reported that the fracture toughness increased discontinuously when the phase fraction of the tempered martensite was over a critical fraction in the heat affected zones of SA508 Gr.3. Therefore, it may be necessary to evaluate the changes of transition behavior with a microstructure for the tempered martensitic SA508 Gr.4N low alloy steel. In this study, the fracture toughness for SA508 Gr.4N low alloy steels was evaluated from a view point of the temperature dependency with phase fraction of tempered martensite controlled by cooling rate. Additionally, a possible modification of the fracture toughness master curve on of the fracture toughness master curve was proposed and discussed

209

Ductile-Brittle Transition Behavior in Tempered Martensitic SA508 Gr. 4N Ni-Mo-Cr Low Alloy Steels for Reactor Pressure Vessels  

Energy Technology Data Exchange (ETDEWEB)

Reactor pressure vessels (RPVs) operate under severe conditions of elevated temperature, high pressure, and irradiation. Therefore, a combination of sufficient strength, toughness, good weldability, and high irradiation resistance are required for RPV materials. SA508 Gr.4N low alloy steel, which has higher Ni and Cr contents than those of commercial RPV steel, Gr.3 steel, is considered as a candidate material due to its excellent mechanical properties from tempered martensitic microstructure. The ferritic steels such as Gr.3 and Gr.4N low alloy steels reveal a ductile-brittle transition and large scatters in the fracture toughness within a small temperature range. Recently, there are some observations of the steeper transition behavior in the tempered martensitic steels, such as Eurofer97 than the transition behavior of commercial RPV steels. It was also reported that the fracture toughness increased discontinuously when the phase fraction of the tempered martensite was over a critical fraction in the heat affected zones of SA508 Gr.3. Therefore, it may be necessary to evaluate the changes of transition behavior with a microstructure for the tempered martensitic SA508 Gr.4N low alloy steel. In this study, the fracture toughness for SA508 Gr.4N low alloy steels was evaluated from a view point of the temperature dependency with phase fraction of tempered martensite controlled by cooling rate. Additionally, a possible modification of the fracture toughness master curve was proposed and discussed

Lee, Ki Hyoung; Wee, Dang Moon [KAIST, Daejeon (Korea, Republic of); Kim, Min Chul; Lee, Bong Sang [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

2010-05-15

210

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)

211

Spirit's Winter Work Site  

Science.gov (United States)

[figure removed for brevity, see original site] Annotated Version This portion of an image acquired by the Mars Reconnaissance Orbiter's High Resolution Imaging Science Experiment camera shows the Spirit rover's winter campaign site. Spirit was parked on a slope tilted 11 degrees to the north to maximize sunlight during the southern winter season. 'Tyrone' is an area where the rover's wheels disturbed light-toned soils. Remote sensing and in-situ analyses found the light-toned soil at Tyrone to be sulfate rich and hydrated. The original picture is catalogued as PSP_001513_1655_red and was taken on Sept. 29, 2006. NASA's Jet Propulsion Laboratory, a division of the California Institute of Technology in Pasadena, manages the Mars Reconnaissance Orbiter for NASA's Science Mission Directorate, Washington. Lockheed Martin Space Systems, Denver, is the prime contractor for the project and built the spacecraft. The High Resolution Imaging Science Experiment is operated by the University of Arizona, Tucson, and the instrument was built by Ball Aerospace and Technology Corp., Boulder, Colo.

2006-01-01

212

Decontamination and winter conditions  

International Nuclear Information System (INIS)

The report deals with two decontamonation experiments under winter conditions. A snow-covered parking lot was contaminated, and the snow was subsequently removed using standard snow-moving equipment. The snow left behind was collected and the content of contaminant was determined. A non-radioactive contaminant was used. A decontamination factor exceeding 100 was obtained. Although the eksperimental conditions were close to ideal, it is reason to believe that extremely efficient removal of deposited materials on a snow surface is achivable. In another investigation, run-off from agricultural surface, contaminated while covered with snow, was measured A lycimeter was used in this experiment. A stable layer of ice and snow was allowed to form before contamination. The run-off water was collected at each thaw period until all snow and ice was gone. Cs-134 was used as contaminant. Roughly 30% of the Cs-134 with which the area was contaminated ran off with the melt water. Following a reactor accident situation, this would have given a corresponding reduction in the long term doses. Both of these experiments show that consequence calculation assumptions, as they are currently applied to large accident assessment, tend to overestimate the consequences resulting from accidents taking place under winter conditions

213

Heat treatment effect on properties of softening zone in the 15Kh11MF steel  

International Nuclear Information System (INIS)

Studied is the effect of heat treatment conditions on a metal softening in the heat affected zone (HAz) of the 15Kh11MF weld-deposited steel. Heating conditions after the weld deposition are determined which provide for a minimum softening. The HAZ metal properties were determined by measuring microhardness, and its structure was studied by the electron microscopy method. It is shown that high-temperature tempering does not remove but increase the softening present in HAZ metal (the 15Kh11MF steel). The strongest effect on the development of softening region at tempering is produced by heating rate and holding-up temperature. The increase in softening intensity at the reheating is due to the enlargement of carbide phase in the regions of high tempering of the weld-deposited steel. Rapid heating for tempering supresses carbide coagulation, which prevents from the development of an additional softening in the 15Kh11MF steel at heat treatment

214

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)

Full Text Available SciELO Argentina | Language: Spanish Abstract in spanish 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.

G., Naranjo; E., Tersoglio.

2010-06-01

215

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  

Directory of Open Access Journals (Sweden)

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.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, they 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.

G. Naranjo

2010-06-01

216

Ice-dependent winter survival of juvenile Atlantic salmon.  

Science.gov (United States)

Changes in snow and ice conditions are some of the most distinctive impacts of global warming in cold temperate and Arctic regions, altering the environment during a critical period for survival for most animals. Laboratories studies have suggested that reduced ice cover may reduce the survival of stream dwelling fishes in Northern environments. This, however, has not been empirically investigated in natural populations in large rivers. Here, we examine how the winter survival of juvenile Atlantic salmon in a large natural river, the River Alta (Norway, 70°N), is affected by the presence or absence of surface ice. Apparent survival rates for size classes corresponding to parr and presmolts were estimated using capture-mark-recapture and Cormack-Jolly-Seber models for an ice-covered and an ice-free site. Apparent survival (?) in the ice-covered site was greater than in the ice-free site, but did not depend on size class (0.64 for both parr and presmolt). In contrast, apparent survival in the ice-free site was lower for larger individuals (0.33) than smaller individuals (0.45). The over-winter decline in storage energy was greater for the ice-free site than the ice-covered site, suggesting that environmental conditions in the ice-free site caused a strong depletion in energy reserves likely affecting survival. Our findings highlight the importance of surface ice for the winter survival of juvenile fish, thus, underpinning that climate change, by reducing ice cover, may have a negative effect on the survival of fish adapted to ice-covered habitats during winter. PMID:23532172

Hedger, R D; Næsje, T F; Fiske, P; Ugedal, O; Finstad, A G; Thorstad, E B

2013-03-01

217

Development of passive design zones in China using bioclimatic approach  

International Nuclear Information System (INIS)

This paper presents the work on development of passive design zones for different climates in China. A total of 18 cities representing the five major climatic types, namely severe cold, cold, hot summer and cold winter, mild and hot summer and warm winter were selected for climatic analysis. Measured weather data were gathered and analysed. A bioclimatic approach was adopted in which the comfort zone and 12 monthly climatic lines were determined and plotted on the psychrometric chart for each city. From these bioclimatic charts, the potential use of passive design strategies such as solar heating, natural ventilation, thermal mass with/without night ventilation and evaporative cooling was assessed. A total of nine passive design strategy zones were identified, and appropriate design strategies suggested for both summer and winter consideration

218

Development of passive design zones in China using bioclimatic approach  

Energy Technology Data Exchange (ETDEWEB)

This paper presents the work on development of passive design zones for different climates in China. A total of 18 cities representing the five major climatic types, namely severe cold, cold, hot summer and cold winter, mild and hot summer and warm winter were selected for climatic analysis. Measured weather data were gathered and analysed. A bioclimatic approach was adopted in which the comfort zone and 12 monthly climatic lines were determined and plotted on the psychrometric chart for each city. From these bioclimatic charts, the potential use of passive design strategies such as solar heating, natural ventilation, thermal mass with/without night ventilation and evaporative cooling was assessed. A total of nine passive design strategy zones were identified, and appropriate design strategies suggested for both summer and winter consideration. (author)

Lam, Joseph C. [Building Energy Research Group, Department of Building and Construction, City University of Hong Kong, Tat Chee Avenue, Kowloon, Hong Kong (China); Yang, Liu; Liu, Jiaping [School of Architecture, Xi' an University of Architecture and Technology, Shaanxi (China)

2006-04-15

219

Sequence variability of Campylobacter temperate bacteriophages  

Directory of Open Access Journals (Sweden)

Full Text Available Abstract Background Prophages integrated within the chromosomes of Campylobacter jejuni isolates have been demonstrated very recently. Prior work with Campylobacter temperate bacteriophages, as well as evidence from prophages in other enteric bacteria, suggests these prophages might have a role in the biology and virulence of the organism. However, very little is known about the genetic variability of Campylobacter prophages which, if present, could lead to differential phenotypes in isolates carrying the phages versus those that do not. As a first step in the characterization of C. jejuni prophages, we investigated the distribution of prophage DNA within a C. jejuni population assessed the DNA and protein sequence variability within a subset of the putative prophages found. Results Southern blotting of C. jejuni DNA using probes from genes within the three putative prophages of the C. jejuni sequenced strain RM 1221 demonstrated the presence of at least one prophage gene in a large proportion (27/35 of isolates tested. Of these, 15 were positive for 5 or more of the 7 Campylobacter Mu-like phage 1 (CMLP 1, also designated Campylobacter jejuni integrated element 1, or CJIE 1 genes tested. Twelve of these putative prophages were chosen for further analysis. DNA sequencing of a 9,000 to 11,000 nucleotide region of each prophage demonstrated a close homology with CMLP 1 in both gene order and nucleotide sequence. Structural and sequence variability, including short insertions, deletions, and allele replacements, were found within the prophage genomes, some of which would alter the protein products of the ORFs involved. No insertions of novel genes were detected within the sequenced regions. The 12 prophages and RM 1221 had a % G+C very similar to C. jejuni sequenced strains, as well as promoter regions characteristic of C. jejuni. None of the putative prophages were successfully induced and propagated, so it is not known if they were functional or if they represented remnant prophage DNA in the bacterial chromosomes. Conclusion These putative prophages form a family of phages with conserved sequences, and appear to be adapted to Campylobacter. There was evidence for recombination among groups of prophages, suggesting that the prophages had a mosaic structure. In many of these properties, the Mu-like CMLP 1 homologs characterized in this study resemble temperate bacteriophages of enteric bacteria that are responsible for contributions to virulence and host adaptation.

Ng Lai-King

2008-03-01

220

Cospecialization of pro-(p') tempered fundamental groups  

CERN Document Server

This paper constructs cospecialization homomorphisms between the (p') versions of the tempered fundamental group of the fibers of a smooth morphism with polystable reduction (the tempered fundamental group is a sort of analog of the topological fundamental group of complex algebraic varieties in the p-adic world). To construct them, we will start by describing the pro-(p') tempered fundamental group of a smooth and proper variety with polystable reduction in terms of the reduction endowed with its log structure, thus defining tempered fundamental groups for log polystable varieties. We will also study invariance of the geometric log fundamental group of saturated log smooth log schemes over a log point by change of log point.

Lepage, Emmanuel

2009-01-01

 
 
 
 
221

Temperate Perennial Grass Response to Defoliation Height and Interval  

Science.gov (United States)

The frequency and extent to which temperate perennial grasses are defoliated influences their productivity and persistence. Field-grown tillers of meadow fescue (Festuca pratensis Huds.), orchardgrass (Dactylis glomerata L.), common quackgrass [Elymus repens (L.) Gould], and reed canarygrass (Phala...

222

Enhanced Sampling in the Well-Tempered Ensemble  

CERN Document Server

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.

Bonomi, M

2009-01-01

223

Enhanced Sampling in the Well-Tempered Ensemble  

Science.gov (United States)

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 , J. Comput. Chem. 30, 1615 (2009)JCCHDD0192-865110.1002/jcc.21305]. We apply WTE and its parallel tempering variant to the 2d Ising model and to a G? model of HIV protease, demonstrating in these two representative cases that convergence is accelerated by orders of magnitude.

Bonomi, M.; Parrinello, M.

2010-05-01

224

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

225

Magnetic nondestructive technology for detection of tempered martensite embrittlement  

Science.gov (United States)

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.

Kashefi, Mehrdad; Rafsanjani, Ali; Kahrobaee, Saeed; Alaee, Moeen

2012-11-01

226

Significance of Rate of Work Hardening in Tempered Martensite Embrittlement  

Digital Repository Infrastructure Vision for European Research (DRIVER)

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...

Pietikainen, J.

1995-01-01

227

Influence of tempering temperature on mechanical properties of cast steels  

Directory of Open Access Journals (Sweden)

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.

G. Gola?ski

2008-12-01

228

Dung beetle communities: a neotropical-north temperate comparison  

Scientific Electronic Library Online (English)

Full Text Available SciELO Brazil | Language: English Abstract in english 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.

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

2010-02-01

229

Spirit Scans Winter Haven  

Science.gov (United States)

At least three different kinds of rocks await scientific analysis at the place where NASA's Mars Exploration Rover Spirit will likely spend several months of Martian winter. They are visible in this picture, which the panoramic camera on Spirit acquired during the rover's 809th sol, or Martian day, of exploring Mars (April 12, 2006). Paper-thin layers of light-toned, jagged-edged rocks protrude horizontally from beneath small sand drifts; a light gray rock with smooth, rounded edges sits atop the sand drifts; and several dark gray to black, angular rocks with vesicles (small holes) typical of hardened lava lie scattered across the sand. This view is an approximately true-color rendering that combines images taken through the panoramic camera's 753-nanometer, 535-nanometer, and 432-nanometer filters.

2006-01-01

230

Winter fuels report  

Energy Technology Data Exchange (ETDEWEB)

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 and 30-Day outlook for temperature and precipitation and US total heating degree-days by city.

1995-02-03

231

The tempered polymerization of human neuroserpin.  

Science.gov (United States)

Neuroserpin, a member of the serpin protein superfamily, is an inhibitor of proteolytic activity that is involved in pathologies such as ischemia, Alzheimer's disease, and Familial Encephalopathy with Neuroserpin Inclusion Bodies (FENIB). The latter belongs to a class of conformational diseases, known as serpinopathies, which are related to the aberrant polymerization of serpin mutants. Neuroserpin is known to polymerize, even in its wild type form, under thermal stress. Here, we study the mechanism of neuroserpin polymerization over a wide range of temperatures by different techniques. Our experiments show how the onset of polymerization is dependent on the formation of an intermediate monomeric conformer, which then associates with a native monomer to yield a dimeric species. After the formation of small polymers, the aggregation proceeds via monomer addition as well as polymer-polymer association. No further secondary mechanism takes place up to very high temperatures, thus resulting in the formation of neuroserpin linear polymeric chains. Most interesting, the overall aggregation is tuned by the co-occurrence of monomer inactivation (i.e. the formation of latent neuroserpin) and by a mechanism of fragmentation. The polymerization kinetics exhibit a unique modulation of the average mass and size of polymers, which might suggest synchronization among the different processes involved. Thus, fragmentation would control and temper the aggregation process, instead of enhancing it, as typically observed (e.g.) for amyloid fibrillation. PMID:22412873

Noto, Rosina; Santangelo, Maria Grazia; Ricagno, Stefano; Mangione, Maria Rosalia; Levantino, Matteo; Pezzullo, Margherita; Martorana, Vincenzo; Cupane, Antonio; Bolognesi, Martino; Manno, Mauro

2012-01-01

232

Candidate Planets in the Habitable Zones of Kepler Stars  

Digital Repository Infrastructure Vision for European Research (DRIVER)

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(HZ) that ...

Gaidos, Eric

2013-01-01

233

Photoperiod and temperature responses of bud swelling and bud burst in four temperate forest tree species.  

Science.gov (United States)

Spring phenology of temperate forest trees is optimized to maximize the length of the growing season while minimizing the risk of freezing damage. The release from winter dormancy is environmentally mediated by species-specific responses to temperature and photoperiod. We investigated the response of early spring phenology to temperature and photoperiod at different stages of dormancy release in cuttings from four temperate tree species in controlled environments. By tracking bud development, we were able to identify the onset of bud swelling and bud growth in Acer pseudoplatanus L., Fagus sylvatica L., Quercus petraea (Mattuschka) Liebl. and Picea abies (L.) H. Karst. At a given early stage of dormancy release, the onset and duration of the bud swelling prior to bud burst are driven by concurrent temperature and photoperiod, while the maximum growth rate is temperature dependent only, except for Fagus, where long photoperiods also increased bud growth rates. Similarly, the later bud burst was controlled by temperature and photoperiod (in the photoperiod sensitive species Fagus, Quercus and Picea). We conclude that photoperiod is involved in the release of dormancy during the ecodormancy phase and may influence bud burst in trees that have experienced sufficient chilling. This study explored and documented the early bud swelling period that precedes and defines later phenological stages such as canopy greening in conventional phenological works. It is the early bud growth resumption that needs to be understood in order to arrive at a causal interpretation and modelling of tree phenology at a large scale. Classic spring phenology events mark visible endpoints of a cascade of processes as evidenced here. PMID:24713858

Basler, David; Körner, Christian

2014-04-01

234

"Winter is coming"  

CERN Document Server

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-...

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

2013-01-01

235

Winter fuels report  

Energy Technology Data Exchange (ETDEWEB)

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.

1995-01-13

236

Winter fuels report  

Energy Technology Data Exchange (ETDEWEB)

The Winter Fuels Report is intended to provide concise, timely information to the industry, the press, policymakers, consumers, analysis, 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.

1995-01-27

237

Development of Roller Ends Forced-Contact Model and Cambering Technology for UCM Temper Mill (II)——Development of cambering technology for UCM temper mill  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Roller ends forced-contact and overmuch roll consumption are the widespread problems in temper rolling process of thin strip for two-stand UCM temper mill. Fully thinking the equipment and technology characteristics of UCM temper mill, we took the newly-built 1220 UCM temper mill of Baosteel as the research object in this paper. A model of roller ends forced-contact and a calculation model of flatness for UCM temper mill are established after a great deal of site tracing and theoretical resea...

Zhenhua Bai; Xiaodong Shi; Hongxin Si; Linfang Han; Ruibing Long; Shoumin Wu; Xiujun Li; Dongdong Zhang

2011-01-01

238

A note on the water budget of temperate glaciers  

Directory of Open Access Journals (Sweden)

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.

J. Oerlemans

2013-06-01

239

Deprivation and excess winter mortality  

Digital Repository Infrastructure Vision for European Research (DRIVER)

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...

Shah, S.; Peacock, J.

1999-01-01

240

Evolution of Microsatellite Loci of Tropical and Temperate Anguilla Eels  

Directory of Open Access Journals (Sweden)

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.

Mei-Chen Tseng

2012-04-01

 
 
 
 
241

Effects of tempering on internal friction of carbon steels  

Energy Technology Data Exchange (ETDEWEB)

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.

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

242

TEM studies of tempered structural steels with Ni  

Directory of Open Access Journals (Sweden)

Full Text Available 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 quenched and tempered conditions. Quenching was performed in oil at room temperature. After quenching samples were tempered at 200°C for 2 h. The microstructure of the investigated steels were investigated using JEM200CX transmission electron microscope.Findings: An increase of Ni content in investigated structural steels causes a decrease of ? carbide concentration in their microstructure after tempering at 200°C for 2 hours. Cementite precipitates in these steels independently on the boundaries of martensite needles boundaries and on the twin boundaries in the areas in which the precipitates of ? carbide dissolved. Research limitations/implications: Presented results may be used to design new technologies of tempering of structural steels with nickel addition.Originality/value: Morphology of ? carbides precipitates.

J. Pacyna

2007-03-01

243

New methods for improving winter road maintenence  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Winter road maintenance activities are crucial for maintaining the accessibility and traffic safety of the road network during winters. Common winter road maintenance activities include plowing and the use of de-icing agents (e.g. NaCl) to avoid freezing. Effective winter road maintenance strives towards keeping the roads free from snow and ice while reducing negative side effects of winter road maintenance, such as ground water contamination from road salt. Since the weather is decisive for ...

Riehm, Mats

2010-01-01

244

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

Science.gov (United States)

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.

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

2012-12-01

245

The Combinatorial Game Theory of Well-Tempered Scoring Games  

CERN Document Server

We consider the class of "well-tempered" integer-valued scoring games, which have the property that the parity of the length of the game is independent of the line of play. We consider disjunctive sums of these games, and develop a theory for them analogous to the standard theory of disjunctive sums of normal-play partizan games. We show that the monoid of well-tempered scoring games modulo indistinguishability is cancellative but not a group, and we describe its structure in terms of the group of normal-play partizan games. We also classify Boolean-valued well-tempered scoring games, showing that there are exactly seventy, up to equivalence.

Johnson, Will

2011-01-01

246

Radiation processing of temperate fruits of Kashmir valley  

International Nuclear Information System (INIS)

Kashmir valley is famous for its temperate horticulture. Main temperate fruits grown commercially in the valley include apple, pear, peach, plum, cherry, strawberry and apricot. These fruits being perishable and susceptible to microbial spoilage, have a short shelf-life. The short shelf-life in an impediment in their transportation and marketing and results in huge losses. Study was carried out at NRL, Srinagar to investigate the effect of gamma irradiation on the keeping quality of most of these fruits. The effect of gamma irradiation alone and in combination with other techniques like controlled low temperature storage, edible polysaccharide coating and calcium chloride treatment was studied in detail. The results revealed that there is a great potential for the use of radiation in extending the storage life of most of the temperate fruits produced in the valley of Kashmir. (author)

247

Magnetic nondestructive technology for detection of tempered martensite embrittlement  

Energy Technology Data Exchange (ETDEWEB)

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 Degree-Sign 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: Black-Right-Pointing-Pointer Occurrence of tempered martensite embrittlement in 4340 AISI steels was evaluated. Black-Right-Pointing-Pointer A reliable relation between EC output and Charpy impact test results was obtained. Black-Right-Pointing-Pointer EC technique was used to separate brittle parts due to the microstructure changes.

Kashefi, Mehrdad; Rafsanjani, Ali [Department of Materials Science and Metallurgical Engineering, Engineering Faculty, Ferdowsi University of Mashhad, Mashhad (Iran, Islamic Republic of); Kahrobaee, Saeed, E-mail: Saeed_kahrobaee@yahoo.com [Department of Materials Science and Metallurgical Engineering, Engineering Faculty, Ferdowsi University of Mashhad, Mashhad (Iran, Islamic Republic of); Alaee, Moeen [Department of Materials Science and Metallurgical Engineering, Engineering Faculty, Ferdowsi University of Mashhad, Mashhad (Iran, Islamic Republic of)

2012-11-15

248

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

249

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

Directory of Open Access Journals (Sweden)

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.

Seung Jin Joo

2011-03-01

250

Insulin-like growth factor 1 and growth seasonality in reindeer (Rangifer tarandus - comparisons with temperate and tropical cervids  

Directory of Open Access Journals (Sweden)

Full Text Available Growth in temperate and arctic deer is seasonal, with higher growth rates in spring and summer while growth rates are low or negative in autumn and winter. We have measured IGF1 concentrations in the plasma of reindeer calves exposed to a manipulated photoperiod, indoors, of either 16 hours light followed by 8 hours dark each day (16L:8D (n = 3 or 8L:16D (n = 3 from about the autumnal to the vernal equinox, to determine whether the seasonal growth spurt normally seen in spring is associated with changes in the circulating level of IGF1. A high quality concentrate diet was available ad libitum. The animals were weighed, and bled every 2 weeks and plasma samples assayed for IGF1 by radioimmunoassay. 6-8 weeks after the start of the study those calves exposed to 16L.-8D showed a significant increase in plasma IGF1 concentration which was maintained until the close of the experiment, 24 weeks after the start. In contrast IGF1 plasma concentrations in those calves exposed to a daylength of 8L:16D did not significantly alter during the study. The elevated IFG1 in the 16L:8D group was associated with rapid weight gain compared with the 8L:16D group. We have shown that the seasonal growth spurt is preceded by an elevation in plasma IFG1 concentration. Further, this elevation in IGF1 is daylength dependent. For comparison IGF1 and growth rate seasonal profiles from temperate and tropical deer are included. This comparison reveals that seasonal increases in IGF1 take place only in animals with a seasonal growth spurt. Thus IGF1 plasma level elevations seem most closely associated with the resumption of rapid growth in spring following the winter.

P. D. Gluckman

1993-12-01

251

Snow surface energy and mass balance in a warm temperate climate mountain  

Science.gov (United States)

In warm temperate mountain regions where water is often scarce vapor losses from the snow-surface can substantially limit snowmelt. Therefore, understanding the key snow dynamic processes that affect water availability in these mountains is essential. We studied the snowpack energy and mass balance in Mt. Hermon, Israel using a comprehensive field campaign during 2010/11. We analyzed the snowpack energy and mass balance during the winter of 2010/11 in a Deep Snow Patch (DSP), and in the Bulan valley experiment area (BVEA), where both windswept locations and lee-side (deep snowpack) locations were examined. We applied for this analysis an energy and mass balance snow model that was forced by input from two meteorological stations. The calibration of the model for the DSP and BVEA was based on surveyed snow water equivalent data, and melting cycles that were measured with time-lapse cameras, respectively. Using a step function to describe wind speed over the DSP we showed that the turbulent fluxes were influenced by changes in snowpack height. The turbulent fluxes were found as the dominant energy fluxes at the snow-surface. During winter, vapor losses varied between 46% and 82% of the total ablation. Consequently, latent heat flux consumed much of the available energy at the snow-surface, greatly limiting melting rate to 1 mm day-1. During spring, vapor flux was positive which enhanced condensation, resulting in an average melting flux of 86 mm day-1. The spatial variation in the vapor flux at the BVEA due to terrain orientation yield variation in space of the available water at the bottom of the snowpack.

Sade, Rotem; Rimmer, Alon; Litaor, M. Iggy; Shamir, Eylon; Furman, Alex

2014-11-01

252

Indoor fungal composition is geographically patterned and more diverse in temperate zones than in the tropics  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Fungi are ubiquitous components of indoor human environments, where most contact between humans and microbes occurs. The majority of these organisms apparently play a neutral role, but some are detrimental to human lifestyles and health. Recent studies that used culture-independent sampling methods demonstrated a high diversity of indoor fungi distinct from that of outdoor environments. Others have shown temporal fluctuations of fungal assemblages in human environments and modest correlations...

Amend, Anthony S.; Seifert, Keith A.; Samson, Robert; Bruns, Thomas D.

2010-01-01

253

Detecting "Temperate" Jupiters: The Prospects of Searching for Transiting Gas Giants in Habitability Zones  

CERN Document Server

This paper investigates the effects of observing windows on detecting transiting planets by calculating the fraction of planets with a given period that have zero, one (single), two (double), or $\\ge$3 (multiple) transits occurring while observations are being taken. We also investigate the effects of collaboration by performing the same calculations with combined observing times from two wide-field transit survey groups. For a representative field of the 2004 observing season, both XO and SuperWASP experienced an increase in single and double transit events by up to 20-40% for planets with periods 14 < P < 150 days when collaborating by sharing data. For the XO Project using its data alone, between 20-40% of planets with periods 14-150 days should have been observed at least once. For the SuperWASP Project, 50-90% of planets with periods between 14-150 days should have been observed at least once. If XO and SuperWASP combined their observations, 50-100% of planets with periods less than 20 days should ...

Fleming, S W; McCullough, P R; Chromey, F R

2008-01-01

254

Catch crops and green manures as biological tools in nitrogen management in temperate zones  

Digital Repository Infrastructure Vision for European Research (DRIVER)

The review deals with the effects of nitrogen catch crops or green manures on the N dynamics of agricultural systems. The mechanisms of their effects are discussed, and it is discussed how they can be used to achieve the agricultural and environmental goals of N management.

Thorup-kristensen, Kristian; Magid, Jacob; Jensen, Lars Stoumann

2003-01-01

255

Fens and floodplains of the temperate zone: Present status, threats, conservation and restoration  

Science.gov (United States)

This Special Feature focuses on lowland fens and flood plains. In this introduction we discuss the most important mire-related terms, present status, threats and conservation and restoration attempts. Floodplains and especially lowland fens are rare and vulnerable ecosystems. They are highly threatened all over the world because of direct conversion to agricultural land and especially the lack of appropriate management and altered catchment hydrology. Finally we present a framework for the conservation and restoration of these ecosystems. This consists of (1) optimising abiotic conditions; (2) safeguarding propagule availability of the target species; (3) creating and maintaining conditions for (re)establishment of these species, and (4) appropriate management to keep the conditions suitable. ?? IAVS; Opulus Press.

Van Diggelen, R.; Middleton, B.; Bakker, J.; Grootjans, A.; Wassen, M.

2006-01-01

256

Detecting "Temperate" Jupiters: The Prospects of Searching for Transiting Gas Giants in Habitability Zones  

Digital Repository Infrastructure Vision for European Research (DRIVER)

This paper investigates the effects of observing windows on detecting transiting planets by calculating the fraction of planets with a given period that have zero, one (single), two (double), or $\\ge$3 (multiple) transits occurring while observations are being taken. We also investigate the effects of collaboration by performing the same calculations with combined observing times from two wide-field transit survey groups. For a representative field of the 2004 observing seas...

Fleming, S. W.; Kane, S. R.; Mccullough, P. R.; Chromey, F. R.

2008-01-01

257

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

Digital Repository Infrastructure Vision for European Research (DRIVER)

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 ...

Vuuren, A. M.; Chilibroste, P.

2013-01-01

258

A comparative analysis of specialization and extinction risk in temperate-zone bats.  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Identifying the factors that influence the extinction risk of animals is essential in conservation biology because they help identify endangered species and provide the basis for their preservation.We present a comparative study that uses data from the literature on the diet and morphological specialization of European and North American bat species to investigate the effect of specialization on extinction risk. We focused on bats because many species are endangered and their high ecologic...

Safi, K.; Kerth, G.

2004-01-01

259

Phosphorus Fertilization of Late-Planted Winter Wheat into No-Till Summer Fallow  

Science.gov (United States)

Winter wheat (Triticum aestivum L.) is planted in low precipitation (< 300 mm) areas of north-central Oregon and east-central Washington after 14 months of tilled fallow. No-till fallow (NTF) is an alternative to the tillage-based method. The disadvantage of NTF is the loss of seed-zone moisture a...

260

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

Directory of Open Access Journals (Sweden)

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.

Peter J. Grubb

2014-10-01

 
 
 
 
261

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

DEFF Research Database (Denmark)

OBJECTIVE: 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. METHOD: We studied this hypothesis among 2910 civil servants from Århus, Denmark, who participated in a survey in January-February 2009. Mental symptoms (N=422) defined a common case category that we broke down into two parts: depression (N=66) and mood difficulties but no depression (N=356). A total of 222 controls were also sampled from the study population. All 644 participants reported the extent of outdoor work. RESULTS: The confounder-adjusted odds ratio (OR) of mood difficulties showed a decreasing trend by increasing hours of outdoor work of borderline statistical significance. The OR was 0.63 [95% confidence interval (95% CI) 0.34-1.18)] for those working outdoors for >2 hours a day. No such effect was suggested for depression. CONCLUSION: Our study is limited by its cross-sectional design and low statistical power but nevertheless suggests that outdoor work during winter may protect against mood difficulties. If this finding holds true it may have significant impact on workers' health as well as public health in general. Therefore, further studies are recommended.

Hahn, Ina H; Grynderup, Matias B

2011-01-01

262

Summer and winter torpor use by a free-ranging marsupial.  

Science.gov (United States)

Torpor is usually associated with low ambient temperatures (T(a)) in winter, but in some species it is also used in summer, often in response to limited food availability. Since the seasonal expression of torpor of both placental and marsupial hibernators in the wild is poorly documented by quantitative data, we investigated torpor and activity patterns of the eastern pygmy-possum Cercartetus nanus (17.4 g) over two seasons. We used radio telemetry to track animals during winter (n=4) and summer (n=5) in a warm-temperate habitat and found that torpor was used in both seasons. In winter all animals entered periods of short-term hibernation (from 5 to 20 days) containing individual torpor bouts of up to 5.9 days. In summer, torpor bouts were always <1 day in duration, only used by males and were not related to daily mean T(a). Pygmy-possums entered torpor at night as T(a) cooled, and rewarmed during the afternoon as T(a) increased. Individuals interspersed torpor bouts with nocturnal activity and the percentage of the night animals were active was the same in summer and winter. Our study provides the first information on torpor patterns in free-ranging C. nanus, and shows that the use of torpor throughout the year is important for energy management in this species. PMID:22487484

Turner, James M; Körtner, Gerhard; Warnecke, Lisa; Geiser, Fritz

2012-07-01

263

The Dallas winter visibility study  

Energy Technology Data Exchange (ETDEWEB)

For some years, a highly visible cloud of polluted air could be seen over the city during winter season stagnation conditions. A historical study of visual range data collected from local airports conducted by the Texas Air Control Board showed a decreasing trend in the number of good visibility days per year over the past 35 years and, that the average visibility has decreased by 50 percent since 1940. Specific data describing the haze composition or source contributions to the winter pollution haze were limited. The purpose of this study, was to determine the composition of the visible haze, and from that information, determine the relative contribution of the various air pollution sources in the Dallas area to winter visibility impairment. Two existing air quality monitoring stations were augmented with additional instrumentation for this study. 18 figs., 18 tabs.

Einfeld, W.; Dattner, S.; Zimmermann, K.

1988-09-01

264

Blast noise characteristics as a function of distance for temperate and desert climates.  

Science.gov (United States)

Variability in received sound levels were investigated at distances ranging from 4 m to 16 km from a typical blast source in two locations with different climates and terrain. Four experiments were conducted, two in a temperate climate with a hilly terrain and two in a desert climate with a flat terrain, under a variety of meteorological conditions. Sound levels were recorded in three different directions around the source during the summer and winter seasons in each location. Testing occurred over the course of several days for each experiment during all 24 h of the day, and meteorological data were gathered throughout each experiment. The peak levels (L(Pk)), C-weighted sound exposure levels (CSEL), and spectral characteristics of the received sound pressure levels were analyzed. The results show high variability in L(Pk) and CSEL at distances beyond 2 km from the source for each experiment, which was not clearly explained by the time of day the blasts occurred. Also, as expected, higher frequency energy is attenuated more drastically than the lower frequency energy as the distance from the source increases. These data serve as a reference for long-distance blast sound propagation. PMID:22779471

Valente, Dan; Ronsse, Lauren M; Pater, Larry; White, Michael J; Serwy, Roger; Nykaza, Edward T; Swearingen, Michelle E; Albert, Donald G

2012-07-01

265

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

Science.gov (United States)

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 < 1 at Cape Grim suggest that a different formation and/or loss processes or rates dominate at each site. Dicarbonyl precursor VOCs, including isoprene and monoterpenes, are used to calculate an upper-estimate yield of glyoxal and methylglyoxal in the remote 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.

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

2015-01-01

266

Isotopic variation across the Audubon's-myrtle warbler hybrid zone.  

Science.gov (United States)

Differences in seasonal migratory behaviours are thought to be an important component of reproductive isolation in many organisms. Stable isotopes have been used with success in estimating the location and qualities of disjunct breeding and wintering areas. However, few studies have used isotopic data to estimate the movements of hybrid offspring in species that form hybrid zones. Here, we use stable hydrogen to estimate the wintering locations and migratory patterns of two common and widespread migratory birds, Audubon's (Setophaga auduboni) and myrtle (S. coronata) warblers, as well as their hybrids. These two species form a narrow hybrid zone with extensive interbreeding in the Rocky Mountains of British Columbia and Alberta, Canada, which has been studied for over four decades. Isotopes in feathers grown on the wintering grounds or early on migration reveal three important patterns: (1) Audubon's and myrtle warblers from allopatric breeding populations winter in isotopically different environments, consistent with band recovery data and suggesting that there is a narrow migratory transition between the two species, (2) most hybrids appear to overwinter in the south-eastern USA, similar to where myrtle warblers are known to winter, and (3) some hybrid individuals, particularly those along the western edge of the hybrid zone, show Audubon's-like isotopic patterns. These data suggest there is a migratory divide between these two species, but that it is not directly coincident with the centre of the hybrid zone in the breeding range. We interpret these findings and discuss them within the context of previous research on hybrid zones, speciation and migratory divides. PMID:24779396

Toews, D P L; Brelsford, A; Irwin, D E

2014-06-01

267

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

268

Tempered Water Lower Port Connector Structural Analysis Verification  

Energy Technology Data Exchange (ETDEWEB)

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.

CREA, B.A.

2000-05-05

269

SEASONAL MORPHOLOGY AND FORAGE QUALITY OF TEMPERATE GRASSES  

Science.gov (United States)

Forage quality of grazed swards is closely associated with the contribution and quality of morphological components. We determined leaf and stem fraction dry matter and forage quality trends for temperate perennial grasses at two Wisconsin locations. After reaching 15 to 20 cm height, primary spri...

270

Dispersal of Aedes aegypti: Field study in temperate areas using a novel method  

Directory of Open Access Journals (Sweden)

Full Text Available Background & objectives: Since Aedes aegypti was identified as vector of yellow fever and dengue, its dispersal is relevant for disease control. We studied the dispersal of Ae. aegypti in temperate areas of Argentina during egglaying, using the existing population and egg traps. Methods: Two independent replicas of a unique experimental design involving mosquitoes dispersing from an urbanized area to adjacent non-urbanized locations were carried out and analyzed in statistical terms. Results: We found relationship between stochastic variables related to the egg-laying mosquito activity (ELMA, useful to assess dispersal probabilities, despite the lack of knowledge of the total number of ovipositions in the zone. We propose to evaluate the egg-laying activity as minus the logarithm of the fraction of negative ovitraps at different distances from the buildings. Interpretation & conclusion: Three zones with different oviposition activity were determined, a corridor surrounding the urbanization, a second region between 10 and 25 m and the third region extending from 30 to 45 m from the urbanization. The landscape (plant cover and the human activity in the area appear to have an influence in the dispersal of Ae. aegypti. The proposed method worked consistently in two different replicas.

Paula E. Bergero

2013-08-01

271

Effect of temper on environmental fatigue crack propagation in 7000-series aluminum alloys  

Energy Technology Data Exchange (ETDEWEB)

In contrast to stress corrosion, the effect of overaging temper on environmental fatigue crack propagation rate in the 7000-series aluminum alloy/aqueous-chloride solution system is nil, moderately beneficial, or detrimental depending on loading frequency. For both peak and overaged AA7075 plate, Paris regime fatigue crack growth rates are accelerated up to 10-fold by cyclic loading in 3.5% NaCl solution compared to fatigue in moist air for the SL-crack orientation. Crack growth is intersubgranular for the T6 microstructure, but transgranular-brittle for the T7 case. Cracking at low f is dominated by corrosion product induced crack closure that is enhanced by overaging. At intermediate to high f, environmental fatigue is due to hydrogen embrittlement and rate limited by H diffusion over a crack tip process zone distance established by local stress. The relationship between plateau crack growth rate and critical frequency for f-dependent EFCP is predicted by a H diffusion model. Plateau regime transgranular-brittle EFCP in overaged AA7075 is slower than intersubgranular cracking in the T6 microstructure, but persists to higher f{sub CRIT}, requiring either rapid H diffusion or reduced crack tip H for process zone embrittlement of the overaged case. (orig.)

Gasem, Z.M.; Gangloff, R.P. [Virginia Univ., Charlottesville, VA (United States). Dept. of Mater. Sci. and Eng.

2000-07-01

272

[Distribution characteristics of benthic algae in intertidal zone of Ma' an Archipelago of Zhejiang Province].  

Science.gov (United States)

Based on the survey of benthic algae in the intertidal zone of Ma' an Archipelago from March to July 2007, the algal species composition, distribution, and temperature feature were studied. The dominant algal species in the study area were preliminarily analyzed by using similarity indices (S(c)) and index of relative importance (IRI(c)). A total of 31 species sampled in sublittoral area were identified, among which, 7 species of 5 genera belonged to Chlorophyta, 8 species of 5 genera belonged to Phaeophyta, and 16 species of 14 genera belonged to Rhodophyta. Topical and selective distribution species influenced by wave and tide were identified in the intertidal zone. Ulva pertusa and Sargassum thunbergii were found in all survey area. Rhodophyta was the dominant species, with the occurring frequency being up to 61.1%, and Chlorophyta showed quite uniformed horizontal distribution. In addition, 81% of sampled species were from low-tide zone, and some were extended from mid-tide zone to low-tide zone. The composition comparability between mid-tide and low-tide species was 0.47, and the convergence effect in mid-tide and low-tide zone was higher than that in high-tide and mid-tide zone. The sublittoral area of Ma' an Archipelago showed obvious vertical zoning character, with temperate species being absolute abundant, and the warm-water species dominant. The marine floral texture of Ma' an Archipelago belongs to warm temperate-subtropical transitional marine flora. PMID:19123370

Zhang, Shou-Yu; Liang, Jun; Wang, Zhen-Hua; Wang, Kai

2008-10-01

273

Peculiarities of Over-Wintering of Linear and Hybrid Winter Rape in Warming-Up Autumn-Winter period  

Digital Repository Infrastructure Vision for European Research (DRIVER)

The experiment carried out in the Experimental Station of Lithuanian University of Agriculture in 2009 – 2010. The soil is shallow calcareous Luvisols (Calc(ar)i-Epihypogleyic Luvisol). The aim of our investigation was to determine the effect of sowing time of winter oilseed rape on autumn rosette chemical composition and over-wintering. Chemical composition of rossete of winter rape sown at different time influenced crop over-wintering – significant correlation between this indicators wa...

Dunauskaite?, Rimante?

2011-01-01

274

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

275

Groundwater flow modelling of periods with temperate climate conditions - Forsmark  

Energy Technology Data Exchange (ETDEWEB)

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

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

276

Root apex transition zone as oscillatory zone.  

Science.gov (United States)

Root apex of higher plants shows very high sensitivity to environmental stimuli. The root cap acts as the most prominent plant sensory organ; sensing diverse physical parameters such as gravity, light, humidity, oxygen, and critical inorganic nutrients. However, the motoric responses to these stimuli are accomplished in the elongation region. This spatial discrepancy was solved when we have discovered and characterized the transition zone which is interpolated between the apical meristem and the subapical elongation zone. Cells of this zone are very active in the cytoskeletal rearrangements, endocytosis and endocytic vesicle recycling, as well as in electric activities. Here we discuss the oscillatory nature of the transition zone which, together with several other features of this zone, suggest that it acts as some kind of command center. In accordance with the early proposal of Charles and Francis Darwin, cells of this root zone receive sensory information from the root cap and instruct the motoric responses of cells in the elongation zone. PMID:24106493

Baluška, František; Mancuso, Stefano

2013-01-01

277

Rural Poultry Populations and Strains in Two Agro-Ecological Zones of Nigeria  

Digital Repository Infrastructure Vision for European Research (DRIVER)

A study was conducted in Plateau State of Nigeria which has two distinct agro-ecological zones; a humid sub-temperate region in the North and a sub-humid hotter region that is part of the Northern Guinea Savanna ecological zone of Nigeria in the South. A sample of 1240 farmers from two Local Governments in each of the two ecological zones were surveyed to assess the poultry population and strains of birds as a prelude to the introduction of interventions for control of Newcastle Disease and o...

Abdu, P. A.; Musa, U.; Dafwang, I. I.; Umoh, J. U.

2010-01-01

278

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

279

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)

280

Particulate organic carbon export from soil and vegetation in temperate mountain regions  

Science.gov (United States)

In assessing the significance of terrestrial particulate organic carbon (POC) export in the global carbon cycle, it is essential to be able to predict the POC yield and its make-up (broadly, fossil versus non-fossil) from any given setting. Because mountains vastly dominate the physical erosion load, an understanding of the processes operating in mountains of different kinds, and what controls them, is necessary. In particular, the dynamics of POC harvest in temperate forested uplands are poorly constrained, despite the large area covered by these zones. C and N concentration and isotopic composition data (for both riverine suspended sediment and carbon stores) are presented from two contrasting temperate mountain regions with vast stocks of soil organic carbon. In the northern Swiss Alps, as discharge increases, POC is initially diluted by lithic material through in-channel clearing, but beyond a threshold POC is added. This happens under moderate flow conditions when hillslopes are activated and rain- induced overland flow delivers soil POC to channels. As a result, the proportion of non-fossil POC increases significantly as discharge and suspended sediment load increase. In contrast to the Swiss Alps, overland flow occurs rarely in the Oregon Cascades and Coast Range. There, hillslope soil is decoupled from the channel, due largely to riparian vegetation that both prevents extensive mobilisation and traps sediment before it reaches the stream. Where channels are aggrading, there is no other input mechanism for soil or bedrock, resulting in very low total sediment and POC yields (and correspondingly high POC concentrations). In the Coast Range, with largely sedimentary rather than volcanic substrate, there is some evidence for hillslope soil mobilisation, but not (under moderate meteorological conditions) on the scale observed in Switzerland. Instead, nearly all POC exported comes from vegetation. Initial dilution of POC through in-channel clearing is still evident, and without subsequent activation of the soil reservoir, Oregon's POC export (per unit area) is around an order of magnitude less than the Swiss system.

Smith, J. C.; Hovius, N.; Galy, A.; Tye, A.; Turowski, J.

2012-04-01

 
 
 
 
281

Ectomycorrhizas in vitro between Tricholoma matsutake, a basidiomycete that associates with Pinaceae, and Betula platyphylla var. japonica, an early-successional birch species, in cool-temperate forests.  

Science.gov (United States)

Tricholoma matsutake is an ectomycorrhizal basidiomycete that associates with Pinaceae in the Northern Hemisphere and produces prized "matsutake" mushrooms. We questioned whether the symbiont could associate with a birch that is an early-successional species in boreal, cool-temperate, or subalpine forests. In the present study, we demonstrated that T. matsutake can form typical ectomycorrhizas with Betula platyphylla var. japonica; the associations included a Hartig net and a thin but distinct fungal sheath, as well as the rhizospheric mycelial aggregate "shiro" that is required for fruiting in nature. The in vitro shiro also emitted a characteristic aroma. This is the first report of an ectomycorrhizal formation between T. matsutake and a deciduous broad-leaved tree in the boreal or cool-temperate zones that T. matsutake naturally inhabits. PMID:25236465

Murata, Hitoshi; Yamada, Akiyoshi; Maruyama, Tsuyoshi; Neda, Hitoshi

2014-09-20

282

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)

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.

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

2014-02-01

283

Spring grazing winter cereals in Montana  

Science.gov (United States)

Winter wheat (Triticum aestivum L.) is widely utilized for winter pasture and grain production in the central and southern US plains. Under rainfed conditions in the northern Great Plains, winter wheat seldom achieves adequate fall biomass for grazing, and little is known about the impacts of grazi...

284

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.)

285

Role of relaxation processes in volume change during steel tempering  

International Nuclear Information System (INIS)

Carbon-free and low-carbon iron-nickel (18 and 10% Ni) alloys and medium-carbon steels alloyed with chromium, manganese and other elements were investigated for volume effects caused by tempering. The results were compared with the calculated values of the volume effect due to the precipitation of cementite and to the variations of the electric resistance, of the X-ray diffraction lines width and of the temperature dependence of the yield limit. It was found that the decrease in volume on the tempering of martensitic steel cannot be explained by the precipitation of carbon alone from the solid solution and the formation of the carbide phase. It is suggested that the decrease in volume is also caused by the healing of martensite structure defects, such as volume- stretched elastic areas of the crystalline lattice

286

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)

287

Effect of tempering on corrosion resistance of cast aluminium bronzes  

International Nuclear Information System (INIS)

The subject of this study is corrosion resistance of aluminium bronzes, which are copper base alloys containing aluminium up to 12% with additions of nickel, iron and manganese. The main conclutions that can be drawn are: (1) The dealloying corrosion resistance of nickel-aluminium bronze is much better than that of aluminium bronze with iron and manganese additions, but it is not immune; (2) The dealloying corrosion resistance of aluminium bronzes can be improved by appropiate heat treatments. The best properties were obtained by temperering between 600 and 800 deg C, depending on the initial microstructure; (3) In crevice conditions, where local acidification can occur, dealloying of aluminium bronzes is a consequence of the preferential attack of aluminium-rich phases. By appropriate tempering, a uniform distribution of aluminium-rich phases is obtained and the continous path for selective corrosion is not formed

288

Linking well-tempered metadynamics simulations with experiments.  

Science.gov (United States)

Linking experiments with the atomistic resolution provided by molecular dynamics simulations can shed light on the structure and dynamics of protein-disordered states. The sampling limitations of classical molecular dynamics can be overcome using metadynamics, which is based on the introduction of a history-dependent bias on a small number of suitably chosen collective variables. Even if such bias distorts the probability distribution of the other degrees of freedom, the equilibrium Boltzmann distribution can be reconstructed using a recently developed reweighting algorithm. Quantitative comparison with experimental data is thus possible. Here we show the potential of this combined approach by characterizing the conformational ensemble explored by a 13-residue helix-forming peptide by means of a well-tempered metadynamics/parallel tempering approach and comparing the reconstructed nuclear magnetic resonance scalar couplings with experimental data. PMID:20441734

Barducci, Alessandro; Bonomi, Massimiliano; Parrinello, Michele

2010-05-19

289

Reversible temper brittleness on tensile tests at room temperature  

International Nuclear Information System (INIS)

Tensile tests were carried out on unnotched test pieces at room temperature and three strain rates: 2,5x10-4, 2,5x10-3 and 1,0x10-2 s-1 in a low alloy No-Cr-Mo steel to observe the variation in its mechanical properties with the occurrence of reversible temper brittleness. The brittle samples showed a sensitivity of 500C in a 48 hour heat treatment at 5000C. The tests showed that at the strain rate of 2,5x10-4 s-1 there are statistically significant differences between the elongations of the material in the brittle and the nonbrittle and regenerated states. A short review of reversible temper brittleness is given and a theory suggested for the mechanism

290

Nitrous oxide emission reduction in temperate biochar-amended soils  

Digital Repository Infrastructure Vision for European Research (DRIVER)

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...

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

2012-01-01

291

Coherent assembly of phytoplankton communities in diverse temperate ocean ecosystems  

Digital Repository Infrastructure Vision for European Research (DRIVER)

The annual cycle of phytoplankton cell abundance is coherent across diverse ecosystems in the temperate North Atlantic Ocean. In Bedford Basin, on the Scotian Shelf and in the Labrador Sea, the numerical abundance of phytoplankton is low in spring and high in autumn, thus in phase with the temperature cycle. Temperature aligns abundance on a common basis, effectively adjusting apparent cell discrepancies in waters that are colder or warmer than the regional norm. As an example of holistic sim...

Li, William K. W.; Glen Harrison, W.; Head, Erica J. H.

2006-01-01

292

Nitrogen response efficiency of a managed and phytodiverse temperate grassland  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Our goal was to assess how management and sward functional diversity affect nitrogen response efficiency (NRE), the ratio of plant biomass production to supply of available nitrogen (N) in temperate grassland.A three-factorial design was employed: three sward compositions, two mowing frequencies, and two fertilization treatments.NRE was largely influenced by fertilization followed by mowing frequency and sward composition. NRE was larger in unfertilized than fertilized plots, in plots cut thr...

Keuter, Andreas; Hoeft, Ina; Veldkamp, Edzo; Corre, Marife

2012-01-01

293

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

294

Straight-cut and tempering oils: enrichment with carcinogenic hydrocarbons  

Energy Technology Data Exchange (ETDEWEB)

A report, Carcinogenic APH concentrations in certain mineral oils - corresponding risks, emphasized the phenomenon of polycondensed hydrocaron pyrosynthesis during the industrial process of oil tempering in metallurgy. This phenomenon is less obvious in manufacture by removing metals. Experiments will be performed either in the laboratory or in industrial environments to scientifically follow the appearance of an increasing concentration of APH in the oil during the experiment and to determine its kinetics.

295

Groundwater flow modelling of periods with temperate climate conditions - Laxemar  

Energy Technology Data Exchange (ETDEWEB)

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

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

296

Computer simulation of quenched and tempered steel properties  

Digital Repository Infrastructure Vision for European Research (DRIVER)

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...

Smoljan, B.; Iljkic?, D.; Novak, H.

2011-01-01

297

Naphthalene biodegradation in temperate and arctic marine microcosms.  

Science.gov (United States)

Naphthalene, the smallest polycyclic aromatic hydrocarbon (PAH), is found in abundance in crude oil, its major source in marine environments. PAH removal occurs via biodegradation, a key process determining their fate in the sea. Adequate estimation of PAH biodegradation rates is essential for environmental risk assessment and response planning using numerical models such as the oil spill contingency and response (OSCAR) model. Using naphthalene as a model compound, biodegradation rate, temperature response and bacterial community composition of seawaters from two climatically different areas (North Sea and Arctic Ocean) were studied and compared. Naphthalene degradation was followed by measuring oxygen consumption in closed bottles using the OxiTop(®) system. Microbial communities of untreated and naphthalene exposed samples were analysed by polymerase chain reaction denaturing gradient gel electrophoresis (PCR-DGGE) and pyrosequencing. Three times higher naphthalene degradation rate coefficients were observed in arctic seawater samples compared to temperate, at all incubation temperatures. Rate coefficients at in situ temperatures were however, similar (0.048 day(-1) for temperate and 0.068 day(-1) for arctic). Naphthalene biodegradation rates decreased with similar Q10 ratios (3.3 and 3.5) in both seawaters. Using the temperature compensation method implemented in the OSCAR model, Q10 = 2, biodegradation in arctic seawater was underestimated when calculated from the measured temperate k1 value, showing that temperature difference alone could not predict biodegradation rates adequately. Temperate and arctic untreated seawater communities were different as revealed by pyrosequencing. Geographic origin of seawater affected the community composition of exposed samples. PMID:23624724

Bagi, Andrea; Pampanin, Daniela M; Lanzén, Anders; Bilstad, Torleiv; Kommedal, Roald

2014-02-01

298

Nanostructure of a cold drawn tempered martensitic steel  

CERN Document Server

The carbon atom distribution in a tempered martensitic steel processed by cold drawing was investigated with a three-dimensional atom probe. Data clearly show that cementite starts to decompose at the early stage of deformation. This indicates that the driving force of cementite decomposition during plastic deformation is not related to a strong increase of the interfacial energy. Carbon atmospheres were also analysed. They probably result from pipe diffusion of carbon atoms along dislocations pined by Fe3C carbides.

Sauvage, X; Malandain, J J; Pareige, P; Sauvage, Xavier; Quelennec, Xavier; Malandain, Jean-Jacques; Pareige, Philippe

2006-01-01

299

Nanostructure of a cold drawn tempered martensitic steel  

Digital Repository Infrastructure Vision for European Research (DRIVER)

The carbon atom distribution in a tempered martensitic steel processed by cold drawing was investigated with a three-dimensional atom probe. Data clearly show that cementite starts to decompose at the early stage of deformation. This indicates that the driving force of cementite decomposition during plastic deformation is not related to a strong increase of the interfacial energy. Carbon atmospheres were also analysed. They probably result from pipe diffusion of carbon atoms...

Sauvage, Xavier; Quelennec, Xavier; Malandain, Jean-jacques; Pareige, Philippe

2006-01-01

300

Nanostructure of a cold drawn tempered martensitic steel  

International Nuclear Information System (INIS)

The carbon atom distribution in a tempered martensitic steel processed by cold drawing was investigated with a three-dimensional atom probe. Data clearly show that cementite starts to decompose at an early stage of deformation. This indicates that the driving force of cementite decomposition during plastic deformation is not related to a strong increase of the interfacial energy. Carbon atmospheres were also analysed. They probably result from pipe diffusion of carbon atoms along dislocations pinned by Fe3C carbides

 
 
 
 
301

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)

302

INDUCTION OF TEMPERATE CYANOPHAGES USING HEAVY METAL - COPPER  

Directory of Open Access Journals (Sweden)

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.

MAREI E.M.

2013-09-01

303

Writing TAFS for Winter Weather  

Science.gov (United States)

"Writing TAFs for Winter Weather" is the fourth unit in the Distance Learning Aviation Course 2 (DLAC2) series on producing TAFs that meet the needs of the aviation community. In addition to providing information about tools for diagnosing winter weather and its related impacts, the module extends the Practically Perfect TAF (PPTAF) process to address an airport’s operational thresholds. By understanding the thresholds at airports for which they produce TAFs, forecasters will be better able to produce a PPTAF. The unit also examines how to communicate effectively the logic and uncertainty using the aviation forecast discussion (AvnFD) and addresses maintaining an effective TAF weather watch and updating the TAF proactively.

2014-09-14

304

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)

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.

V. Maruši?

2015-04-01

305

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

Energy Technology Data Exchange (ETDEWEB)

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.

IRWIN, J.J.

1998-11-30

306

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

307

Local adaptation to winter conditions in a passerine spreading north: a common-garden approach.  

Science.gov (United States)

Sedentary passerine birds living in temperate and boreal regions need a high metabolic capacity for thermogenesis to survive winter conditions. As a consequence of the increased thermogenic capacity, basal energetic demands rise at a time when resources and time to acquire them decrease. In a previous study, great tits (Parus major) from two localities in Fennoscandia with contrasting winter conditions differed in their metabolic response to ambient temperature. To investigate the physiological basis underlying interpopulation differences we performed a common-garden experiment to test whether these differences were genetically based. We found basal metabolic rate to be higher in birds originating from transferred eggs from the southern population compared to the ones from the northern population, contrary to the relationship among birds living in their region of origin. Despite previous evidence suggesting that gene flow prevents local adaptation at the northern range limits of a species expanding northward, we found that great tits differ in their reaction norm to winter conditions according to the population of origin. PMID:16153046

Broggi, Juli; Hohtola, Esa; Orell, Markku; Nilsson, Jan-Ake

2005-07-01

308

Intraspecific Variation in Leaf Life Span for the Semi-evergreen Liana Akebia trifoliata is Caused by Both Seasonal and Aseasonal Factors in a Temperate Forest  

Directory of Open Access Journals (Sweden)

Full Text Available We investigated the leaf demography of a temperate woody liana, Akebia trifoliata, in a temperateforest in Japan. Akebia is semi-evergreen: some leaves are shed before winter, while others remain through thewinter. Previous studies of semi-evergreen species found that variation in leaf life span was caused by variationin the timing of leaf emergence. Leaves that appeared just before winter over-wintered, while leaves appearingearlier were shed. However, it is unclear whether leaves of the same cohort (i.e., leaves that appear at the sametime within a single site show variation in life span under the effect of strong seasonality. To separate variationin life span among the leaves in each cohort from variation among cohorts, we propose a new method - thesingle leaf diagram, which shows the emergence and death of each leaf. Using single leaf diagrams, our studyrevealed that Akebia leaves within a cohort showed substantial variation in life span, with some over-winteringand some not. In addition, leaves on small ramets in the understory showed great variation in life span, whileleaves on large ramets, which typically reach higher positions in the forest canopy, have shorter lives. As a result,small ramets were semi-evergreen, whereas large ramets were deciduous. The longer lives of leaves on smallramets can be interpreted as a shade-adaptive strategy in understory plants.

Koyama, Kohei

2008-08-01

309

The tropicalization of temperate marine ecosystems: climate-mediated changes in herbivory and community phase shifts.  

Science.gov (United States)

Climate-driven changes in biotic interactions can profoundly alter ecological communities, particularly when they impact foundation species. In marine systems, changes in herbivory and the consequent loss of dominant habitat forming species can result in dramatic community phase shifts, such as from coral to macroalgal dominance when tropical fish herbivory decreases, and from algal forests to 'barrens' when temperate urchin grazing increases. Here, we propose a novel phase-shift away from macroalgal dominance caused by tropical herbivores extending their range into temperate regions. We argue that this phase shift is facilitated by poleward-flowing boundary currents that are creating ocean warming hotspots around the globe, enabling the range expansion of tropical species and increasing their grazing rates in temperate areas. Overgrazing of temperate macroalgae by tropical herbivorous fishes has already occurred in Japan and the Mediterranean. Emerging evidence suggests similar phenomena are occurring in other temperate regions, with increasing occurrence of tropical fishes on temperate reefs. PMID:25009065

Vergés, Adriana; Steinberg, Peter D; Hay, Mark E; Poore, Alistair G B; Campbell, Alexandra H; Ballesteros, Enric; Heck, Kenneth L; Booth, David J; Coleman, Melinda A; Feary, David A; Figueira, Will; Langlois, Tim; Marzinelli, Ezequiel M; Mizerek, Toni; Mumby, Peter J; Nakamura, Yohei; Roughan, Moninya; van Sebille, Erik; Gupta, Alex Sen; Smale, Dan A; Tomas, Fiona; Wernberg, Thomas; Wilson, Shaun K

2014-08-22

310

Ecotypes of Planktonic Actinobacteria with Identical 16S rRNA Genes Adapted to Thermal Niches in Temperate, Subtropical, and Tropical Freshwater Habitats  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Seven strains with identical 16S rRNA genes affiliated with the Luna2 cluster (Actinobacteria) were isolated from six freshwater habitats located in temperate (Austria and Australia), subtropical (People's Republic of China), and tropical (Uganda) climatic zones. The isolates had sequence differences at zero to five positions in a 2,310-nucleotide fragment of the ribosomal operon, including part of the intergenic spacer upstream of the 16S rRNA gene, the complete 16S rRNA gene, the complete 1...

Hahn, Martin W.; Po?ckl, Matthias

2005-01-01

311

Comparison of N2O Emissions from Soils at Three Temperate Agricultural Sites  

Science.gov (United States)

Nitrous oxide (N2O) flux simulations by four models were compared with year-round field measurements from five temperate agricultural sites in three countries. The field sites included an unfertilized, semi-arid rangeland with low N2O fluxes in eastern Colorado, USA; two fertilizer treatments (urea and nitrate) on a fertilized grass ley cut for silage in Scotland; and two fertilized, cultivated crop fields in Germany where N2O loss during the winter was quite high. The models used were daily trace gas versions of the CENTURY model, DNDC, ExpertN, and the NASA-Ames version of the CASA model. These models included similar components (soil physics, decomposition, plant growth, and nitrogen transformations), but in some cases used very different algorithms for these processes. All models generated similar results for the general cycling of nitrogen through the agro-ecosystems, but simulated nitrogen trace gas fluxes were quite different. In most cases the simulated N20 fluxes were within a factor of about 2 of the observed annual fluxes, but even when models produced similar N2O fluxes they often produced very different estimates of gaseous N loss as nitric oxide (NO), dinitrogen (N2), and ammonia (NH3). Accurate simulation of soil moisture appears to be a key requirement for reliable simulation of N2O emissions. All models simulated the general pattern of low background fluxes with high fluxes following fertilization at the Scottish sites, but they could not (or were not designed to) accurately capture the observed effects of different fertilizer types on N2O flux. None of the models were able to reliably generate large pulses of N2O during brief winter thaws that were observed at the two German sites. All models except DNDC simulated very low N2O fluxes for the dry site in Colorado. The US Trace Gas Network (TRAGNET) has provided a mechanism for this model and site intercomparison. Additional intercomparisons are needed with these and other models and additional data sets; these should include both tropical agro-ecosystems and new agricultural management techniques designed for sustainability.

Frolking, S. E.; Moiser, A. R.; Ojima, D. S.; Li, C.; Parton, W. J.; Potter, C. S.; Priesack, E.; Stenger, R.; Haberbosch, C.; Dorsch, P.; Peterson, David L. (Technical Monitor)

1997-01-01

312

Bionomics of temperate and tropical culicoides midges: knowledge gaps and consequences for transmission of culicoides-borne viruses.  

Science.gov (United States)

Culicoides midges are abundant hematophagous flies that vector arboviruses of veterinary and medical importance. Dramatic changes in the epidemiology of Culicoides-borne arboviruses have occurred since 1998, including the emergence of exotic viruses in northern temperate regions, increases in global disease incidence, and enhanced virus diversity in tropical zones. Drivers may include changes in climate, land use, trade, and animal husbandry. New Culicoides species and new wild reservoir hosts have been implicated in transmission, highlighting the dynamic nature of pathogen-vector-host interactions. Focusing on potential vector species worldwide and key elements of vectorial capacity, we review the sensitivity of Culicoides life cycles to abiotic and biotic factors. We consider implications for designing control measures and understanding impacts of environmental change in different ecological contexts. Critical geographical, biological, and taxonomic knowledge gaps are prioritized. Recent developments in genomics and mathematical modeling may enhance ecological understanding of these complex arbovirus systems. PMID:25386725

Purse, B V; Carpenter, S; Venter, G J; Bellis, G; Mullens, B A

2015-01-01

313

Altitudinal variation in soil organic carbon stock in coniferous subtropical and broadleaf temperate forests in Garhwal Himalaya  

Directory of Open Access Journals (Sweden)

Full Text Available Abstract Background The Himalayan zones, with dense forest vegetation, cover a fifth part of India and store a third part of the country reserves of soil organic carbon (SOC. However, the details of altitudinal distribution of these carbon stocks, which are vulnerable to forest management and climate change impacts, are not well known. Results This article reports the results of measuring the stocks of SOC along altitudinal gradients. The study was carried out in the coniferous subtropical and broadleaf temperate forests of Garhwal Himalaya. The stocks of SOC were found to be decreasing with altitude: from 185.6 to 160.8 t C ha-1 and from 141.6 to 124.8 t C ha-1 in temperature (Quercus leucotrichophora and subtropical (Pinus roxburghii forests, respectively. Conclusion The results of this study lead to conclusion that the ability of soil to stabilize soil organic matter depends negatively on altitude and call for comprehensive theoretical explanation

Kumar Munesh

2009-08-01

314

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

Science.gov (United States)

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.

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

315

The influence of kinetics of phase transformations during tempering on high-speed steels mechanical properties  

Digital Repository Infrastructure Vision for European Research (DRIVER)

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 studie...

Ba?a, P.; Pacyna, J.

2010-01-01

316

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)

317

Nekton response to freshwater inputs in a temperate European estuary with regulated riverine inflow.  

Science.gov (United States)

The aim of this 12-year study was to assess the nekton (fish, decapod crustaceans) response to freshwater inputs (rainfall, dam discharges) in a temperate estuary with regulated riverine inflow. Although interannual variability in river discharges to the Guadalquivir estuary has been extremely high since the construction of a dam in 1930, a significant decreasing trend in the dam's discharges has been observed in the last 80 years. During this study, an alternation of wet, standard and dry years occurred in the estuarine area but no significant long-term trend was observed. River discharge, in turn, showed a considerable interannual variability and a significantly decreasing long-term trend. Freshwater inputs had an immediate effect on estuarine salinity and turbidity, and consequently on prey availability (mysids). Although 124 nektonic species were collected, only 47 of them (adding up to 99.7% of total abundance) were regularly present in the estuary: 32 marine migrants, 13 estuarine species and 2 diadromous species. Well-defined temporal changes in species composition and abundance yielded clear seasonal patterns in the estuarine nektonic community. Considerable intermonth and interannual changes were occasionally observed relating to freshwater inputs, mainly in winter/autumn of wet years. Thus, within each two-month period, some significant interannual differences in the nektonic community were also observed, with marine migrants tending to be more abundant in dry years. However, changes in the studied nektonic community did not show long-term trends. In conclusion, natural and human-controlled freshwater inputs currently play a significant role in determining the physicochemical conditions and the biota of the Guadalquivir estuary. However, although freshwater input seemed to transitorily affect the estuarine nekton, either directly (flushing out) or indirectly (through changes in salinity, turbidity and prey availability), a quick reestablishment of the estuarine nekton (strong resilience) was observed following freshwater inputs together with the recovery of environmental conditions within the estuary. PMID:22795595

González-Ortegón, E; Subida, M D; Arias, A M; Baldó, F; Cuesta, J A; Fernández-Delgado, C; Vilas, C; Drake, P

2012-12-01

318

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

DEFF Research Database (Denmark)

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.

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

2008-01-01

319

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

Science.gov (United States)

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.

Florea, Lee J.

2013-05-01

320

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

Science.gov (United States)

Land-atmosphere exchange of carbon dioxide (CO2) in peatlands exhibits marked seasonal and inter-annual variability, which subsequently affects the carbon 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. NEE has been measured continuously by eddy-covariance at Auchencorth Moss, a temperate lowland peatland in central Scotland, since 2002. Hence this is one of the longest peatland NEE studies to date. For 11 yr, 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 a phenological memory-effect. Plant productivity exhibited a marked hysteresis with respect to photosynthetically active radiation (PAR) over the growing season, indicative of two separate growth regimes. Ecosystem respiration (Reco) and gross primary productivity (GPP) were closely correlated (ratio 0.74), suggesting that autotrophic processes were dominant. Whilst the site was wet most of the year (water table depth long-term NEE records. The CO2 uptake rate during the growing season was comparable to 3 other European sites, however the emission rate during the dormant season was significantly higher.

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

2014-10-01

 
 
 
 
321

Mosquito Species Associated Within Some Western Himalayas Phytogeographic Zones in the Garhwal Region of India  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Thirty four species of mosquitoes (Diptera: Culicidae) were collected across three phytogeographic zones; tropical (300 to 1000 m), sub tropical (1000 to 2000 m) and temperate (2000 to 3000 m) in the Garhwal region of India. They included 5 genera: Aedes, Anopheles, Armigeres, Culex and Uranotaenia. Of these, the immature forms of 23 species were recovered from different breeding habitats. The larval habitats were seepage pools, river beds, rice fields, tanks, forest pools, ditches, streams, ...

Pemola Devi, N.; Jauhari, R. K.

2007-01-01

322

Estimating monthly and yearly dependable rainfall for different climatic zones of the world  

Digital Repository Infrastructure Vision for European Research (DRIVER)

The study has demonstrated that estimating monthly or yearly dependable rainfall is not an easy task, especially where rainfall data series are not available. The world is divided into four climatic zones namely: tropical, sub-tropical, mediterranean and temperate. The results showed that no single equation or procedure is quite adequate to describe the different climatic conditions of the world. Three procedures were developed for estimating yearly and monthly dependable rainfall for yearly/...

Aminul Haque, M.

2005-01-01

323

Specificity of salt marsh diazotrophs for vegetation zones and plant hosts  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Salt marshes located on the east coast of temperate North America are highly productive, typically nitrogen-limited, and support diverse assemblages of nitrogen fixing (diazotrophic) bacteria. The distributions of these diazotrophs are strongly influenced by plant host and abiotic environmental parameters. Crab Haul Creek Basin, North Inlet, SC, USA is a tidally dominated marsh that displays discrete plant zones distributed along an elevation gradient from the tidal creek bank to the terrest...

DebraAlineDavis; CharlesRLovell

2012-01-01

324

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

Directory of Open Access Journals (Sweden)

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

AssafSukenik

2012-03-01

325

Development of Roller Ends Forced-Contact Model and Cambering Technology for UCM Temper Mill (II——Development of cambering technology for UCM temper mill  

Directory of Open Access Journals (Sweden)

Full Text Available Roller ends forced-contact and overmuch roll consumption are the widespread problems in temper rolling process of thin strip for two-stand UCM temper mill. Fully thinking the equipment and technology characteristics of UCM temper mill, we took the newly-built 1220 UCM temper mill of Baosteel as the research object in this paper. A model of roller ends forced-contact and a calculation model of flatness for UCM temper mill are established after a great deal of site tracing and theoretical researches. On this basis, an optimal mathematical model of roll shape which is suited for UCM temper mill is developed. Working roll curve is the combination of cosine curve and high order curve. The cosine subentry is used to control edge wave, the high order curve subentry is used to control roller ends forced-contact. Furthermore, the chamfering curve of middle roller end is optimized. Those are the innovations. Through the above-mentioned technology, pressure distribution between rollers caused by the shift of middle roll becomes more homogeneous, pressure peak disappeared, working life of roll is improved effectively as well. Relevant technologies have been used to the practice of 1220 UCM temper mill of Baosteel and have achieved good use effects, which is of further extending application value.

Zhenhua Bai

2011-07-01

326

Standardized Precipitation Index Zones for México  

Scientific Electronic Library Online (English)

Full Text Available SciELO Mexico | Language: English Abstract in spanish 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

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

2005-01-01

327

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

Directory of Open Access Journals (Sweden)

Full Text Available 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. Results In this study, the possible temperate A. nidulans was treated with different concentrations of heavy metal-copper. CuSO4 with concentrations of 3.1 × 10-3 M, 3.1 × 10-4 M, 3.1 × 10-5 M and 3.1 × 10-6 M were used to detect the induction of AS-1 from A. nidulans. The population of the host, unicellular cyanobacteria Anacystis nidulans, was monitored by direct count and turbidity while the amount of virus produced was derived from plaque forming units (PFU by a direct plating method. The ratio of AS-1 release from A. nidulans was also determined. From these results it appears that AS-1 lysogenic phage can be induced by copper at concentrations from 3.1 × 10-6 M to 3.1 × 10-4 M. Maximal phage induction occurred at 6 hours after addition of copper, with an optimal concentration of 3.1 × 10-6 M. Conclusion Cu2+ is a significant inducer for lysogenic cyanobacterial cells and consequently would be a potential control agent in the cyanobacteria population in fresh water ecosystems.

Chu Tin-Chun

2006-02-01

328

Comparison of produced water toxicity to Arctic and temperate species.  

Science.gov (United States)

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

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

2015-03-01

329

The Research and Application of Webpage Temper-proofing System  

Directory of Open Access Journals (Sweden)

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.

Wang Yongquan

2012-06-01

330

Transport in the spatially tempered, fractional Fokker-Planck equation  

Energy Technology Data Exchange (ETDEWEB)

A study of truncated Levy 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, lambda, and on the order of the fractional derivative in space, alpha. An expansion of the TFD operator for large lambda 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 lambda -> infinity, the PDF approaches the expected Boltzmann distribution. However, nontrivial departures from this distribution are observed for finite (lambda > 0) truncations, and alpha not equal 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 lambda -> infinity, the PDFs converges to the Boltzmann distribution and the current vanishes. However, for alpha not equal 2, the PDF deviates from the Boltzmann distribution and a finite non-equilibrium ratchet current appears for any lambda > 0. The current is observed to converge exponentially in time to the steady-state value. The steady-state current exhibits algebraical decay with lambda, as J similar to lambda(-zeta), for alpha >= 1.75. However, for alpha <= 1.5, the steady-state current decays exponentially with lambda, as J similar to e(-xi lambda). 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 lambda and the physical parameters of the system.

Kullberg, A. [University of California, Los Angeles; Del-Castillo-Negrete, Diego B [ORNL

2012-01-01

331

Anatomical structure of the annual shoots axis of introduced Pterostyrax species due to their winter hardiness  

Directory of Open Access Journals (Sweden)

Full Text Available The similarity of the anatomical structure of the axis of annual shoots of Pterostyrax hispida (Sieb. et Zucc. and P. c o r y m b o s a (Sieb. et Zucc. has established. One of the possible reasons for high winter hardiness of these plants in the introduction is a thick layer of cuticle, sclerenchyma on the periphery of the stem, and intense lignifications of histological elements of bark, wood and perymedulyar zone.

Y.V. Kosar

2012-03-01

332

Thermodynamic Properties of Polypeptide Chains. Parallel Tempering Monte Carlo Simulations  

International Nuclear Information System (INIS)

A coarse-grained model of polypeptide chains was designed and studied. The chains consisted of united atoms located at the position of alpha carbons and the coordinates of these atoms were restricted to a [310] type lattice. Two kinds of amino acids residues were defined: hydrophilic and hydrophobic ones. The sequence of the residues was assumed to be characteristic for ?-helical proteins (the helical septet). The force field used consisted of the long-range contact potential between residues and the local potential preferring conformational states, which were characteristic for ?-helices. In order to study the thermodynamics of our model we employed the Multi-histogram method combined with the Parallel Tempering (the Replica Exchange) Monte Carlo sampling scheme. The optimal set of temperatures for the Parallel Tempering simulations was found by an iterative procedure. The influence of the temperature and the force field on the properties of coil-to-globule transition was studied. It was shown that this method can give more precise results when compared to Metropolis and Replica Exchange methods. (author)

333

Nitrous oxide emission reduction in temperate biochar-amended soils  

Directory of Open Access Journals (Sweden)

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.

R. Felber

2012-01-01

334

Environmental drivers of ectomycorrhizal communities in Europe's temperate oak forests.  

Science.gov (United States)

Ectomycorrhizal fungi are major ecological players in temperate forests, but they are rarely used in measures of forest condition because large-scale, high-resolution, standardized and replicated belowground data are scarce. We carried out an analysis of ectomycorrhizas at 22 intensively monitored long-term oak plots, across nine European countries, covering complex natural and anthropogenic environmental gradients. We found that at large scales, mycorrhizal richness and evenness declined with decreasing soil pH and root density, and with increasing atmospheric nitrogen deposition. Shifts in mycorrhizas with different functional traits were detected; mycorrhizas with structures specialized for long-distance transport related differently to most environmental variables than those without. The dominant oak-specialist Lactarius quietus, with limited soil exploration abilities, responds positively to increasing nitrogen inputs and decreasing pH. In contrast, Tricholoma, Cortinarius and Piloderma species, with medium-distance soil exploration abilities, show a consistently negative response. We also determined nitrogen critical loads for moderate (9.5-13.5 kg N/ha/year) and drastic (17 kg N/ha/year) changes in belowground mycorrhizal root communities in temperate oak forests. Overall, we generated the first baseline data for ectomycorrhizal fungi in the oak forests sampled, identified nitrogen pollution as one of their major drivers at large scales and revealed fungi that individually and/or in combination with others can be used as belowground indicators of environmental characteristics. PMID:25277863

Suz, Laura M; Barsoum, Nadia; Benham, Sue; Dietrich, Hans-Peter; Fetzer, Karl Dieter; Fischer, Richard; García, Paloma; Gehrman, Joachim; Kristöfel, Ferdinand; Manninger, Miklós; Neagu, Stefan; Nicolas, Manuel; Oldenburger, Jan; Raspe, Stephan; Sánchez, Gerardo; Schröck, Hans Werner; Schubert, Alfred; Verheyen, Kris; Verstraeten, Arne; Bidartondo, Martin I

2014-11-01

335

Prediction of quenched and tempered steel and cast steel properties  

Directory of Open Access Journals (Sweden)

Full Text Available Purpose: The influence of processing parameters, such as pouring temperature and cooling rate during the casting, as well as application of hot working and pre-heat treatment, on strength and toughness of quenched and tempered steel was investigated.Design/methodology/approach: Strength and toughness were presented by yield strength and Charpy-V notch toughness, respectively. Experimental procedure of material properties optimization was done using the 25-2 factor experiment.Findings: It was found out that yield strength is insensitive on differences between applied manufacturing processes, but by application of hot working and with appropriate pouring temperature the Charpy-V notch toughness is increased. Also, Charpy-V notch toughness is increased by interactive effect of the appropriate cooling rate during the casting and application of hot working.Research limitations/implications: The research was focused mainly on Charpy-V notch toughness of carbon and low alloyed heat treatable steels.Practical implications: The established algorithms can be used for prediction of tensile strength, yield strength and Charpy-V notch toughness in heat treating practice.Originality/value: Original relation for prediction of quenched and tempered steel and cast steel Charpy-V notch toughness are developed.

B. Smoljan

2011-12-01

336

Winter emissions of carbon dioxide, methane and nitrous oxide from a minerotrophic fen under nature conservation management in north-east Germany  

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Full Text Available Drained peatlands are known to be important sources of carbon dioxide (CO2 and nitrous oxide (N2O. While CO2 emissions occur mainly during the growing season, large N2O emissions may occur during the non-growing season as well. Peatland re-wetting may be an effective measure to prevent those emissions. However, recent research shows that re-wetted peatlands may release large amounts of methane (CH4 during the years immediately after re-wetting whereas abandonment of intensive grassland on drained peat soils possibly leads to low nutrient supply and thus to small greenhouse gas (GHG emissions. Here we examine the role of extensification practices (such as abandonment of mineral fertilisation, reduced cutting frequency and a cattle-free winter period on GHG emissions from a temperate peatland during winter. From November 2009 to March 2010 GHG measurements were made on a minerotrophic fen five years after intensive grassland use was abandoned. During the measurement period CO2 and N2O emissions amounted to 4.4 t ha-1 and 2.6 t ha-1 CO2-equivalent, whilst CH4 emissions were negligible. Altogether the site emitted 7 t ha-1 CO2-equivalent, of which 37 % was N2O, even though the winter 2009/2010 was extraordinarily cold. Thus, extensification of grassland use alone may not be sufficient to reduce GHG emissions from temperate peatlands.

V. Huth

2012-04-01

337

Precipitation evolution in an Al-Zn-Mg alloy during non-isothermal heat treatments and in the heat-affected zone of welded joints.  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Welding of Al-Zn-Mg alloys is increasingly used in the transportation industry. The optimisation of the welding process requires a good understanding of the microstructures generated by the rapid temperature rise in the heat-affected zone.This study deals with the evolution of the precipitation state after welding of the 7108.50 alloy in different initial tempers. A quantitative characterisation of the hardening precipitates in the heat-affected zone has been carried out by SAXS, TEM an...

Nicolas, Myriam

2002-01-01

338

Temperate Ice Depth Sounding Radar (TIDSoR)  

Science.gov (United States)

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.

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

2007-12-01

339

Effect of tempering level on mechanical properties and toughness of spring steels  

Energy Technology Data Exchange (ETDEWEB)

the influence of tempering level and of environmental temperature on the mechanical properties of four spring steels was studied. Despite the similar tensile behaviour of the steels tempered at the same hardness level, the toughness properties significantly differed. The importance of a proper material and heat treatment selection is therefore emphasized. (orig.)

Gariboldi, E. (Politecnico di Milano, Dipt. di Meccanica (Italy)); Nicodemi, W. (Politecnico di Milano, Dipt. di Meccanica (Italy)); Silva, G. (Politecnico di Milano, Dipt. di Meccanica (Italy)); Vedani, M. (Politecnico di Milano, Dipt. di Meccanica (Italy))

1994-01-01

340

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

 
 
 
 
341

The effects of boro-tempering heat treatment on microstructural properties of ductile iron  

International Nuclear Information System (INIS)

In this study, the effects of boro-tempering heat treatment on microstructural properties of ductile iron were investigated. Test samples with dimensions of 10 x 10 x 55 mm were boronized at 900 oC for 1, 3 and 5 h and then tempered at four different temperatures (250, 300, 350 and 450 oC) for 1 h. Both optical microscopy and scanning electron microscopy were used to reveal the microstructural details of coating and matrix of boro-tempered ductile iron. X-ray diffraction was used to determine the constituents of the coating layer. The boride layer formed on the surface of boro-tempered ductile cast iron is tooth shape form and consisted of FeB and Fe2B phases. The thickness of boride layer increases as the boronizing time increases and tempering temperature decreases. Tempering temperature is more effective than boronizing time on the matrix structure. Boro-tempering heat treatment reduces the formation of lower and upper ausferritic matrix temperature according to classical austempering. This causes formation of upper ausferritic matrix in the sample when tempered at 300 oC. This is in contrast to general case which is the formation of lower ausferritic matrix via austempering at this temperature.

342

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

Directory of Open Access Journals (Sweden)

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.

Fu Hanguang

2012-08-01

343

75 FR 55811 - Testing Method of Pressed and Toughened (Specially Tempered) Glassware  

Science.gov (United States)

...center punch test. For example, a tempered mug which is subjected to the center punch test...pieces smaller than those of an annealed mug. The commenter indicates that their client...test performed on a tempered fluorosilicate mug; and one is of the center punch test...

2010-09-14

344

Zoned Plagioclase Exercise  

Science.gov (United States)

The purpose of this exercise is to: become familiar with the various types of zoning found to occur in plagioclase feldspars, be able to recognize and identify the various zoning types, and be able to interpret the petrogenesis of the various zoning types from optical and microprobe data. Additionally, the exercise is to give the student an opportunity to interpret analytical data and to engage in critical thinking as it relates to igneous petrology of volcanic rocks.

R. K. Smith

345

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

Directory of Open Access Journals (Sweden)

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.

M. Wisshak

2010-05-01

346

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

Directory of Open Access Journals (Sweden)

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.

M. Wisshak

2010-08-01

347

[The epileptogenic zone].  

Science.gov (United States)

The definition of the epileptogenic zone is a concept proposed by Jean Bancaud and Jean Talairach based on the anatomical, electrical and clinical correlations established from stereoelectroencephalographic recordings. They believed the epileptogenic zone to be the "region of the beginning and the primary organization" of ictal discharges. The opinion of North American authors is different: the epileptogenic zone is the "what to remove area" to produce freedom from seizures. This surgical definition assumes postsurgical validation. The aim of this paper is to show how to define the epileptogenic zone from all the stereoelectroencephalographic recording data. PMID:18440034

Kahane, P; Landré, E

2008-05-01

348

High methane emissions from a littoral zone on the Qinghai-Tibetan Plateau  

Science.gov (United States)

The littoral zones of lakes have been regarded as hotspots of methane (CH 4) fluxes through several studies. In the present study, we measured CH 4 fluxes in six kinds of littoral zones of Huahu Lake on the Qinghai-Tibetan Plateau in the peak growing season of 2006 and 2007. We found that CH 4 efflux (ranging from -0.1 to 90 mg CH 4 m -2 h -1) from the littoral zones of this lake was relatively high among those of boreal and temperate lakes. Our results also showed that emergent plant zones ( Hippuris vulgaris and Glyceria maxima stands) recorded the highest CH 4 flux rate. The CH 4 flux in the floating mat zone of Carex muliensis was significantly lower than those of the emergent plant zones. CH 4 fluxes in the floating-leaved zone of Polygonum amphibium and bare lakeshore showed no significant difference and ranked last but one, only higher than that of the littoral meadow ( Kobresia tibetica). Plant biomass and standing water depths were important factors to explain such spatial variations in CH 4 fluxes. No significant temporal variations in CH 4 fluxes were found due to the insignificant variations of physical factors in the peak growing season. These results may help in our understanding of the importance of the littoral zone of lakes, especially the emergent plant zone, as a hotspot of CH 4 emission.

Chen, Huai; Wu, Ning; Yao, Shouping; Gao, Yongheng; Zhu, Dan; Wang, Yanfen; Xiong, Wan; Yuan, Xingzhong

349

The winter St. Helena climate index and extreme Benguela upwelling  

Science.gov (United States)

Climate changes in the subtropical South-east Atlantic turn out to be well described by the St. Helena Island Climate Index (HIX) and observed fluctuations are in good agreement with inter-decadal variability of the entire South Atlantic Ocean. Year-to-year variations of the averaged austral winter HIX (July-September), representative of the main upwelling season, were compared with (i) corresponding averages of the geostrophic alongshore component of the south-east trade wind (SET) between St. Helena Island in the south-west and Luanda/Angola in the north-east, (ii) the meridional distribution of surface waters colder than 13 °C to characterise intense Benguela upwelling (IBU), and (iii) the meridional position of the Angola-Benguela Frontal Zone (ABFZ) determined by means of sea surface temperature images for offshore distances between 50 and 400 km. Temporal changes of these parameters were investigated and showed that the frequency of consecutive years of strong and relaxed Benguela upwelling is characterised by a quasi-cycle of about 11-14 years. It is proposed that the index of the winter HIX may be used as a 'surveyor's rod' to describe interannual changes in the Benguela upwelling regime as well as those of the embedded marine ecosystem.

Hagen, Eberhard; Agenbag, Jacobus J.; Feistel, Rainer

2005-09-01

350

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

Science.gov (United States)

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).

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

2010-12-01

351

Predictability of northern Adriatic winter conditions  

Science.gov (United States)

Presented results indicate that a long-term (several months ahead) forecast of the winter northern Adriatic conditions is possible and that it can be based on the analysis of meteorological conditions and geostrophic circulation fields of the previous autumn. Using 1981-2007 February data we show that in winters of the type A, salinity in the northern Adriatic is lower and production of phytoplankton higher than in the B type winters. This indicates that the impact of the Po River waters on the northern Adriatic is more pronounced during the A type winters. The two types, A and B, have already been identified on the basis of the bottom density differences between eastern and western part of the northern Adriatic but more precise definition is given here. Based on the data collected during hydrographic cruises in 2000 (type B conditions) and 2001 (type A conditions), we found that the two winters differed in geostrophic circulation patterns as well. Eastward of the Po River delta there was a large cyclonic gyre in 2000 and a large anticyclonic gyre in 2001. Circulation patterns were highly dependent on autumn conditions, with bottom density changes as the most likely triggering cause. Strong surface heat losses and many bora episodes preceded the winter of 2000, while moderate cooling and sirocco events preceded the winter of 2001.

Supi?, Nastjenjka; Kraus, Romina; Kuzmi?, Milivoj; Paschini, Elio; Precali, Robert; Russo, Aniello; Vilibi?, Ivica

2012-02-01

352

The Fracture Process of Tempered Soda-Lime-Silica Glass  

DEFF Research Database (Denmark)

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.

Nielsen, Jens Henrik; Olesen, John Forbes

2009-01-01

353

Enhanced Monte Carlo Sampling through Replica Exchange with Solute Tempering  

Science.gov (United States)

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

2015-01-01

354

Antarctic, Sub-Antarctic and cold temperate echinoid database  

Directory of Open Access Journals (Sweden)

Full Text Available This database includes spatial data of Antarctic, Sub-Antarctic and cold temperate echinoid distribution (Echinodermata: Echinoidea collected during many oceanographic campaigns led in the Southern Hemisphere from 1872 to 2010. The dataset lists occurrence data of echinoid distribution south of 35°S latitude, together with information on taxonomy (from species to genus level, sampling sources (cruise ID, sampling dates, ship names and sampling sites (geographic coordinates and depth. Echinoid occurrence data were compiled from the Antarctic Echinoid Database (David et al., 2005a, which integrates records from oceanographic cruises led in the Southern Ocean until 2003. This database has been upgraded to take into account data from oceanographic cruises led after 2003. The dataset now reaches a total of 6160 occurrence data that have been checked for systematics reliability and consistency. It constitutes today the most complete database on Antarctic and Sub-Antarctic echinoids.

Benjamin Pierrat

2012-06-01

355

Influence of titanium on the tempering structure of austenitic steels  

International Nuclear Information System (INIS)

The microstructure of titanium-stabilized and initially deformed (approximately 20%) austenitic stainless steels used in structures of fast neutrons reactors has been studied after one hour duration annealings (500 0C) by X-ray diffraction, optical microscopy, microhardness and transmission electron microscopy. The studied alloys were either of industrial type CND 17-13 (0.23 to 0.45 wt% Ti) or pure steels (18% Cr, 14% Ni, 0 or 0.3 wt% Ti). During tempering, the pure steels presented some restauration before recristallization. In the industrial steels, only recristallization occurred, and this only in the most deformed steel. Precipitation does not occur in the titanium-free pure steel. In industrial steels, many intermetallic phases are formed when recristallization starts

356

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

Directory of Open Access Journals (Sweden)

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.

Roberto Bertoni

2012-01-01

357

Influence of tempering on mechanical properties of ferritic martensitic steels  

Energy Technology Data Exchange (ETDEWEB)

In the mid-1980s research programs for development of low activation materials began. This is based on the US Nuclear Regulatory Commission Guidelines (10CFR part 61) that were developed to reduce long-lived radioactive isotopes, which allows nuclear reactor waste to be disposed of by shallow land burial when removed from service. Development of low activation materials is also key issue in nuclear fusion systems, as the structural components can became radioactive due to nuclear transmutation caused by exposure to high dose neutron irradiation. Reduced-activation ferritic martensitic (RAFM) steels have been developed in the leading countries in nuclear fusion technology, and are now being considered as primary candidate material for the test blanket module (TBM) in the international thermonuclear experiment reactor (ITER). RAFM steels developed so far (e.g., EUROFER 97 and F82H) meet the requirement for structural application in the ITER. However, if such alloys are used in the DEMO or commercial fusion reactor is still unclear, as the reactors are designed to operate under much severe conditions (i.e., higher outlet coolant temperature and neutron fluences). Such harsh operating conditions lead to development of RAFM steels with better creep and irradiation resistances. Mechanical properties of RAFM steels are strongly affected by microstructural features including the distribution, size and type of precipitates, dislocation density and grain size. For a given composition, such microstructural characteristics are determined mainly by thermo-mechanical process employed to fabricate the final product, and accordingly a final heat treatment, i.e., tempering is the key step to control the microstructure and mechanical properties. In the present work, we investigated mechanical properties of the RAFM steels with a particular attention being paid to effects of tempering on impact and creep properties.

Chun, Y. B.; Han, C. H.; Choi, B. K.; Lee, D. W.; Kim, T. K.; Jeong, Y. H. [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of); Cho, S. [National Fusion Research Institute, Daejeon (Korea, Republic of)

2012-10-15

358

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.

359

Influence of tempering on mechanical properties of ferritic martensitic steels  

International Nuclear Information System (INIS)

In the mid-1980s research programs for development of low activation materials began. This is based on the US Nuclear Regulatory Commission Guidelines (10CFR part 61) that were developed to reduce long-lived radioactive isotopes, which allows nuclear reactor waste to be disposed of by shallow land burial when removed from service. Development of low activation materials is also key issue in nuclear fusion systems, as the structural components can became radioactive due to nuclear transmutation caused by exposure to high dose neutron irradiation. Reduced-activation ferritic martensitic (RAFM) steels have been developed in the leading countries in nuclear fusion technology, and are now being considered as primary candidate material for the test blanket module (TBM) in the international thermonuclear experiment reactor (ITER). RAFM steels developed so far (e.g., EUROFER 97 and F82H) meet the requirement for structural application in the ITER. However, if such alloys are used in the DEMO or commercial fusion reactor is still unclear, as the reactors are designed to operate under much severe conditions (i.e., higher outlet coolant temperature and neutron fluences). Such harsh operating conditions lead to development of RAFM steels with better creep and irradiation resistances. Mechanical properties of RAFM steels are strongly affected by microstructural features including the distribution, size and type of precipitates, dislocation density and grain size. For a given compo density and grain size. For a given composition, such microstructural characteristics are determined mainly by thermo-mechanical process employed to fabricate the final product, and accordingly a final heat treatment, i.e., tempering is the key step to control the microstructure and mechanical properties. In the present work, we investigated mechanical properties of the RAFM steels with a particular attention being paid to effects of tempering on impact and creep properties

360

Evolution of temperate pathogens: the bacteriophage/bacteria paradigm  

Directory of Open Access Journals (Sweden)

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.

Koch Arthur L

2007-11-01

 
 
 
 
361

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)

362

Development of Roller Ends Forced-Contact Model and Cambering Technology for UCM Temper Mill (I)——Development of Roller Ends Forced-Contact Model and the Computational Model of Flatness for UCM temper mill  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Roller ends forced-contact and overmuch roll consumption are the widespread problems in temper rolling process of thin strip for two-stand UCM temper mill. Fully thinking the equipment and technology characteristics of UCM temper mill, we took the newly-built 1220 UCM temper mill of Baosteel as the research object in this paper. A model of roller ends forced-contact and a calculation model of flatness for UCM temper mill are established after a great deal of site tracing and theoretical resea...

Zhenhua Bai; Hongxin Si; Xiaodong Shi; Linfang Han; Ruibing Long; Shoumin Wu; Xiujun Li; Dongdong Zhang

2011-01-01

363

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

Directory of Open Access Journals (Sweden)

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.

Noriega, Teresa

2002-08-01

364

Seasonal dynamics of wintering waterbirds in two shallow lakes along Yangtze River in Anhui Province.  

Science.gov (United States)

The shallow lake wetlands in the middle and lower Yangtze River floodplain are important wintering and stopover habitats for migratory waterbirds on the East Asia-Australia Flyway. With increasing fishery practices in recent years, however, the wetlands have deteriorated significantly and now threaten wintering waterbirds. To gain insight into the influence of deteriorating wetlands on waterbirds, we conducted a survey of wintering waterbird species, population size, and distribution across 11 belt transects in Caizi Lake and Shengjin Lake, two shallow lakes along the Yangtze River in Anhui Province from November 2007-April 2008 and from November 2008-April 2009, respectively. The impacts of different fishery patterns on the distribution of waterbirds were also analyzed. A total of 43 waterbirds species belong to 7 orders of 12 families were counted during the surveys, of which 38 were found in Caizi Lake with a density of 8.2 ind./hm(2), and 42 in Shengjin Lake with a density of 3.5 ind./hm(2). Geese (Anser cygnoides), bean geese (Anser fabalis), tundra swan (Cygnus columbianus), and dunlin (Calidris alpina) were the dominant species in the two shallow lakes. Species number and individual assemble reached maximum at the end of December and in early January of the following year, without coincidence of the largest flock for different ecological groups. Based on waterbird diversity across the 11 belt transects and the fishery patterns, habitats could be divided into three groups. Gruiformes, Anseriformes and Charadriiformes had relatively higher densities in the natural fishery zones and lower densities in the cage fishery zones; whereas, the density of Ardeidae showed little change across all lake zones. It is important to develop sustainable fishery patterns in shallow lakes along the middle and lower Yangtze River floodplain to better protect resources of wintering waterbirds. PMID:22006808

Chen, Jin-Yun; Zhou, Li-Zhi; Zhou, Bo; Xu, Ren-Xin; Zhu, Wen-Zhong; Xu, Wen-Bin

2011-10-01

365

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)

Full Text Available SciELO Brazil | Language: Portuguese Abstract in portuguese 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.

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

2010-03-01

366

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

Directory of Open Access Journals (Sweden)

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 revenimento. 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.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 submitted 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.

Ana Paula Ciscato Camillo

2010-03-01

367

An approach to the determination of winter chill requirements for different Ribes cultivars.  

Science.gov (United States)

Winter chilling is critical for flowering and fruiting of many temperate fruits, with evidence that blackcurrant (Ribes nigrum L.) cropping has been adversely affected by warm winters. Accurate models of chill accumulation in blackcurrant are required so that breeding strategies can be formulated for the generation of new cultivars with resilience to future climates. Existing models for chill accumulation have largely been derived from statistical correlation; here we report the derivation of improved models for blackcurrant using controlled environment treatments. Hardwood cuttings from a diverse set of cultivars were exposed to constant or varying chilling temperatures and the effects on bud break after transfer to a warm, permissive environment evaluated. The impact of different combinations of temperature and chilling periods were described in terms of their overall 'Effectiveness' (E). Clear genotypic differences were found, with excessive chilling often inhibiting bud break. There was a significant interaction between observed chilling response and the period of low temperature exposure. A number of chilling models to explain observed interactions between chilling temperature and time of exposure on bud break were compared; the most effective involved an optimal response to increasing chill accumulation. The effects of varying temperatures during chilling on bud break were complex, with warm temperature breaks substantially inhibiting bud development and cooler temperature breaks tending to enhance bud burst. The relevance of these models to generic studies of endodormancy is discussed, together with their potential application to the development of phenotyping screens for future breeding using diverse blackcurrant germplasm. PMID:22512943

Jones, H G; Hillis, R M; Gordon, S L; Brennan, R M

2013-01-01

368

Trace Metal Cycling Within Riparian Wetland and Hyporhiec Regions Of A Northern Temperate Stream Catchment  

Science.gov (United States)

Our study addresses trace element cycles and metal-binding ligand production and transport within riparian wetland and hyporheic zones of stream catchments. The research is being carried out at extensively instrumented stream catchments in the Northern Temperate Lakes Region of north-central Wisconsin - a system that is also under investigation by the NSF-funded Long Term Ecosystem Research (LTER) program and the USGS Water Energy and Biogeochemical Budgets (WEBB) program. Within the study system we have identified flow paths of contrasting redox, in addition to zones of positive and negative ground water recharge. Detailed temporal data sets of water and ligand chemistry data are being obtained from dense networks of nested piezometers and hyporheic samplers placed in these contrasting regions/flow paths. In addition to major element chemistry, data on over 25 trace metals are acquired using high-resolution ICP-MS. Variations in groundwater flow direction and velocity are key factors driving chemistry in the hyporheic zone. Discharging hyporheic systems are characterized by sub-surface constituent peaks, reflecting, in part, an increased residence time due to the interaction of upwelling groundwater and entrained stream water. Sub-surface peaks are typically absent form recharging systems. Sulfate reduction and iron redox cycling are associated with active cycling of Cu, Zn, and several other trace metals within the hyporheic zone. DOM cycling also appears to influence metal chemistry in the hyporheic, both indirectly through OM oxidation and coupled sulfate and nitrate reduction, and apparently directly via complexation (e.g. with cadmium). Sulfate supply, primarily sourced from surface water, is limiting sulfide production in the hyporheic during certain periods of the year. Stream chemistry variations, particularly in the recharging system, are important drivers of hyporheic major and trace element cycling, as in addition to sulfate, levels of DOM and several trace elements are substantially greater in surface water than groundwater. The importance of sulfide and iron in regulating ground water fluxes of certain trace metals to the stream is also evident when oxic and anoxic flow paths are compared. Along a predominantly oxic flow path from regional ground water to stream riparian porewaters, concentrations of both Mn and Zn drop markedly (10-100 fold). Arsenic is also lost to riparian and wetland sediments. Levels of Cu along anoxic flowpaths (0.06 nM Cu, 50-700 nM sulfide, 30-40,000 nM Fe) are strikingly reduced from that observed in oxic zones (4-6 nM, Cu, <20 nM sulfide, 100 nM Fe). Studies are in progress to characterize the oxidation state of Cu in the contrasting micro-environments. Large seasonal variations in Pb levels are observed, with particularly elevated concentrations seen in spring, coinciding with greater DOC fluxes.

Shafer, M. M.; Kerr, S.; Overdier, J.

2005-12-01

369

Atom Probe Tomography Examination of Carbon Redistribution in Quenched and Tempered 4340 Steel  

Energy Technology Data Exchange (ETDEWEB)

Quenching and tempering produces a wide range of mechanical properties in medium carbon, low alloyed steels - Study fragmentation behavior as a function of heat-treatment. Subtle microstructural changes accompany the mechanical property changes that result from quenching and tempering - Characterize the location and distribution of carbon and alloying elements in the microstructure using atom probe tomography (APT). Perform complementary transmission electron microscopy (TEM). Tempering influences the mechanical properties and fragmentation of quenched 4340 (hemi-shaped samples). APT revealed carbon-enriched features that contain a maximum of {approx}12-14 at.% carbon after quenching to RT (the level of carbon is perhaps associated with the extent of autotempering). TEM confirmed the presence of twinned martensite and indicates {var_epsilon} ({eta}) transition carbides after oil quenching to RT. Tempering at 325 C resulted in carbon-enriched plates (> 25 at.% C) with no significant element partitioning (transition carbides?). Tempering at 450 C and 575 C resulted in cementite ({approx} 25 at.% C) during late stage tempering; Cr, Mn, Mo partitioned to cementite and Si partitioned to ferrite. Tempering at 575 C resulted in P segregation at cementite interfaces and the formation of Cottrell atmospheres.

Clarke, Amy J. [Los Alamos National Laboratory; Miller, Michael K. [ORNL; Alexander, David J. [Los Alamos National Laboratory; Field, Robert D. [Los Alamos National Laboratory; Clarke, Kester D. [Los Alamos National Laboratory

2012-08-07

370

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

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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.

Milan Mutavdži?

2012-06-01

371

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

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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. 

Milan Mutavdži?

2012-05-01

372

The effect of carbide precipitate morphology on fracture toughness in low-tempered steels containing Ni.  

Science.gov (United States)

Nickel is known to increase the resistance to cleavage fracture of iron and decrease a ductile-to-brittle transition temperature. The medium-carbon, low-alloy martensitic steels attain the best combination of properties in low-tempered condition, with tempered martensite, retained austenite and transition carbides in the microstructure. This paper is focused on the influence of Ni addition (from 0.35 to 4.00%) on the microstructure and fracture toughness of structural steels after tempering. In this research, four model alloys of different concentration of Ni and constant concentration of carbon and other elements were used. All samples were in as-quenched and tempered conditions. Quenching was performed in oil at room temperature. After quenching, samples were tempered at 200 degrees C for 2 h. The microstructure of the investigated steels was analyzed using JEM200CX transmission electron microscope. An increase of nickel content in the investigated structural steels causes a decrease of epsilon carbide concentration in their microstructure after tempering. In these steels, cementite precipitates independently in the boundaries of martensite needles and in the twin boundaries in the areas where the Fe(2.4)C carbide has been dissolved. These results will be used to design new technologies of tempering of structural steels with nickel addition. PMID:20500408

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

2010-03-01

373

Preliminary Studies on Plants with Anthelmintic Properties in Kashmir—The North-West Temperate Himalayan Region of India  

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Full Text Available There is a growing interest in traditional uses of plants for health care among different communities especially in the developing countries. Kashmir valley is a temperate agro-climatic zone of north-west temperate Himalayan region of India and is blessed with a diverse variety of medicinal flora. The traditional uses of plants against parasitic infections in human beings and their live-stock is a common practice in the valley as most of the populations are rural and conventional veterinary drugs are very expensive and therefore unaffordable. This study is an ethno-botanical survey of those plant species traditionally used as anthelmintic that may warrant scientific validation for efficacy. The survey utilized well structured questionnaire and detailed discussions and recorded 44 plant species belonging to 37 genera and 26 families claimed as traditional anthelmintics in different preparations and forms. Out of these some plant species like Artemisia absinthium (tethwen and Achillea millifolium (pahel-ghassa were scientifically validated for their claimed anthelmintic action against gastrointestinal nematode infections in sheep. A few of other plants like Allium sativum (rohun, Myrsine africana have been scientifically validated for their claim by other people in various parts of the world. These plants together with other species reported in this study could be further scientifically evaluated for in vitro and in vivo anthelmintic activity against a diverse variety of parasitic groups in host and non host animals. That will lay a foundation and set a targeted platform for pharmacological studies and development of novel anthelmintic products to fill a gap in the anthelmintic drug industry, which is facing the crisis of anthelmintic resistance to conventional anthelmintic drugs.

Mudasir A. Tantry

2012-03-01

374

Long-term persistence and leaching of Escherichia coli in temperate maritime soils.  

Science.gov (United States)

Enteropathogen contamination of groundwater, including potable water sources, is a global concern. The spreading on land of animal slurries and manures, which can contain a broad range of pathogenic microorganisms, is considered a major contributor to this contamination. Some of the pathogenic microorganisms applied to soil have been observed to leach through the soil into groundwater, which poses a risk to public health. There is a critical need, therefore, for characterization of pathogen movement through the vadose zone for assessment of the risk to groundwater quality due to agricultural activities. A lysimeter experiment was performed to investigate the effect of soil type and condition on the fate and transport of potential bacterial pathogens, using Escherichia coli as a marker, in four Irish soils (n = 9). Cattle slurry (34 tonnes per ha) was spread on intact soil monoliths (depth, 1 m; diameter, 0.6 m) in the spring and summer. No effect of treatment or the initial soil moisture on the E. coli that leached from the soil was observed. Leaching of E. coli was observed predominantly from one soil type (average, 1.11 +/- 0.77 CFU ml(-1)), a poorly drained Luvic Stagnosol, under natural rainfall conditions, and preferential flow was an important transport mechanism. E. coli was found to have persisted in control soils for more than 9 years, indicating that autochthonous E. coli populations are capable of becoming naturalized in the low-temperature environments of temperate maritime soils and that they can move through soil. This may compromise the use of E. coli as an indicator of fecal pollution of waters in these regions. PMID:20038692

Brennan, Fiona P; O'Flaherty, Vincent; Kramers, Gaelene; Grant, Jim; Richards, Karl G

2010-03-01

375

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

DEFF Research Database (Denmark)

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

Jacobsen, D.; Dangles, O.

2010-01-01

376

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

Science.gov (United States)

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.

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

2014-05-01

377

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

378

Keep Dogs and Cats Safe During Winter  

Science.gov (United States)

... JavaScript. Keep Dogs and Cats Safe During Winter Veterinarian offers tips for helping your pets stay warm ... to pets unless it is prescribed by your veterinarian. Be sure to check with your veterinarian before ...

379

Essential Outdoor Sun Safety Tips for Winter  

Science.gov (United States)

... enjoyment and may even improve your performance while skiing! Be Mindful of Time Spent in the Sun, ... breaks indoors to reapply sunscreen. Drink plenty of water to avoid dehydration. Enjoy the winter season, but ...