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1

Aerosol influenza transmission risk contours: A study of humid tropics versus winter temperate zone  

Directory of Open Access Journals (Sweden)

Full Text Available Abstract Background In recent years, much attention has been given to the spread of influenza around the world. With the continuing human outbreak of H5N1 beginning in 2003 and the H1N1 pandemic in 2009, focus on influenza and other respiratory viruses has been increased. It has been accepted for decades that international travel via jet aircraft is a major vector for global spread of influenza, and epidemiological differences between tropical and temperate regions observed. Thus we wanted to study how indoor environmental conditions (enclosed locations) in the tropics and winter temperate zones contribute to the aerosol spread of influenza by travelers. To this end, a survey consisting of 632 readings of temperature (T) versus relative humidity (RH) in 389 different enclosed locations air travelers are likely to visit in 8 tropical nations were compared to 102 such readings in 2 Australian cities, including ground transport, hotels, shops, offices and other publicly accessible locations, along with 586 time course readings from aircraft. Results An influenza transmission risk contour map was developed for T versus RH. Empirical equations were created for estimating: 1. risk relative to temperature and RH, and 2. time parameterized influenza transmission risk. Using the transmission risk contours and equations, transmission risk for each country's locations was compared with influenza reports from the countries. Higher risk enclosed locations in the tropics included new automobile transport, luxury buses, luxury hotels, and bank branches. Most temperate locations were high risk. Conclusion Environmental control is recommended for public health mitigation focused on higher risk enclosed locations. Public health can make use of the methods developed to track potential vulnerability to aerosol influenza. The methods presented can also be used in influenza modeling. Accounting for differential aerosol transmission using T and RH can potentially explain anomalies of influenza epidemiology in addition to seasonality in temperate climates.

Hanley Brian P; Borup Birthe

2010-01-01

2

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.

1993-01-01

3

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

4

Sperm competition in tropical versus temperate zone birds.  

UK PubMed Central (United Kingdom)

Sperm competition represents an important component of post-copulatory sexual selection. It has been argued that the level of sperm competition declines in birds towards the equator. However, to date, sperm competition estimates have been available mainly for avian species inhabiting the northern temperate zone. Here we apply a novel approach, using the coefficient of between-male variation (CV(bm)) in sperm size as an index for sperm competition risk, in a comparative analysis of 31 Afrotropical and 99 northern temperate zone passerine species. We found no difference in sperm competition risk between the two groups, nor any relationship with migration distance. However, a multivariate model indicated that sperm competition risk was highest in species with a combination of low body mass and few eggs per clutch. The effect of clutch size was most pronounced in tropical species, which indicates that sperm competition risk in tropical and temperate species is differently associated with particular life-history traits. Although tropical species had lower sperm competition risk than temperate zone species for overlapping clutch sizes, the idea of a generally reduced risk of sperm competition in tropical birds was not supported by our analysis.

Albrecht T; Kleven O; Kreisinger J; Laskemoen T; Omotoriogun TC; Ottosson U; Reif J; Sedlá?ek O; Ho?ák D; Robertson RJ; Lifjeld JT

2013-02-01

5

Role of temperate zone forests in the global carbon cycle  

Energy Technology Data Exchange (ETDEWEB)

Recent growth and harvest trends in commercial timberlands of the temperate zone suggest that these forests have been serving as a net sink for about 1.0 x 10/sup 9/ to 1.2 x 10/sup 9/t of carbon annually over the past 3 decades. This is 20 to 60% of the annual carbon release from combustion of fossil fuels over the period, indicating that recovery transients in temperate zone forests apparently have been partially dampening the increase in atmospheric CO/sub 2/ caused by fossil fuel combustion and tropical forest reduction. Net forest growth is occurring throughout the temperate zone with principal carbon sinks found in North America and in Siberia. Timber inventories for North America show an excess of growth over harvest equivalent to over 5 x 10/sup 15/ g of C since the 1950s. Limited data suggest that in Siberia there is a large stock of slowly growing conifers that are underexploited, forming a sink equivalent to that of North America. Reafforestation in western Europe has expanded forest area by 5% since World War II. Similar recovery may now be occurring in temperate Asia. Problems of data reliability, particularly for the USSR, and the limited basis for estimating carbon balance in entire forests, suggest a severalfold uncertainty in the carbon sink estimates.

Armentano, T.V. (Inst. of Ecology, Indianapolis, IN); Ralston, C.W.

1980-01-01

6

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

UK PubMed Central (United Kingdom)

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 E; Severini C; Picot S

2013-01-01

7

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

8

Forecasting temperate alpine glacier survival from accumulation zone observations  

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Full Text Available Temperate alpine glacier survival is dependent on the consistent presence of an accumulation zone. Frequent low accumulation area ratio values, below 30%, indicate the lack of a consistent accumulation zone, which leads to substantial thinning of the glacier in the accumulation zone. This thinning is often evident from substantial marginal recession, emergence of new rock outcrops and surface elevation decline in the accumulation zone. In the North Cascades 9 of the 12 examined glaciers exhibit characteristics of substantial accumulation zone thinning; marginal recession or emergent bedrock areas in the accumulation zone. The longitudinal profile thinning factor, f, which is a measure of the ratio of thinning in the accumulation zone to that at the terminus, is above 0.6 for all glaciers exhibiting accumulation zone thinning characteristics. The ratio of accumulation zone thinning to cumulative mass balance is above 0.5 for glacier experiencing substantial accumulation zone thinning. Without a consistent accumulation zone these glaciers are forecast not to survive the current climate or future additional warming. The results vary considerably with adjacent glaciers having a different survival forecast. This emphasizes the danger of extrapolating survival from one glacier to the next.

M. S. Pelto

2010-01-01

9

Controls on winter ecosystem respiration in temperate and boreal ecosystems  

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

2011-01-01

10

WINTER CARBON FLUXES IN HUMID-TEMPERATE PASTURES  

Science.gov (United States)

Because of their vast size, grazing lands have the potential to sequester significant quantities of carbon, slowing the increase in atmospheric CO2 and reducing the risk of global warming. Although C uptake during the growing season can be substantial, losses during winter months can significantly ...

11

Forecasting temperate alpine glacier survival from accumulation zone observations  

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

M. S. Pelto

2009-01-01

12

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

Energy Technology Data Exchange (ETDEWEB)

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

Chow, Tin-tai; Lin, Zhang; Fong, Kwong-fai; Chan, Lok-shun; He, Miao-miao [Building Energy and Environmental Technology Research Unit, Division of Building Science and Technology, College of Science and Engineering, City University of Hong Kong, Tat Chee Avenue, Kowloon, Hong Kong SAR (China)

2009-08-15

13

Algal biomass and primary production within a temperate zone sandstone  

Energy Technology Data Exchange (ETDEWEB)

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

Bell, R.A.; Sommerfeld, M.R. (Arizona State Univ., Tempe (USA))

1987-02-01

14

Prospective significance of temperate-zone carbon pool transients, 1980-2010  

Energy Technology Data Exchange (ETDEWEB)

The extent to which the temperate zone sink for carbon will be limited by increased forest utilization is a major question for biospheric carbon balances over the next two decades. Over the past 100 years, shifts in global carbon pools have operated asynchronously, with carbon storage at any time dependent on the net difference between opposing fluxes. Overall, however, the regrowth and soil sequestering transients of the last 60 years in the temperate zone have tended to balance releases of carbon from other sources. Increased utilization of forests and other biospheric pools for fibre and energy, however, may bring about similar responses worldwide with the temperate zone behaving more as a source of carbon dioxide. Analysis shows that the net carbon increment in US forests could be greatly reduced or eliminated in 20 to 30 years if an annual harvest rate of wood equivalent to 10 quads of energy prevails. The increment would be lost even if complete use of logging and manufacturing residues were attained. Without complete residue utilization for energy, the carbon increment would be depleted more rapidly. Forest loss patterns in other temperate zone countries appear to be following similar trends.

Armentano, T.V.; Loucks, O.L.

1981-01-01

15

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

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

Francisco J Pérez; Juan Ormeño N; Bryan Reynaert; Sebastián Rubio

2008-01-01

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

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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 contraction of the austral westerlies with future warming, but the available paleoclimate records that might test these models have been largely limited to South America, are not fully consistent with each other, and may be complicated by influences from other climatic factors. Here we present the first fine-interval diatom and sedimentological records from the winter rainfall region of South Africa, representing precipitation during the last 1400 yr. Inferred rainfall increased ~1400–1200 cal yr BP and most notably during the Little Ice Age with pulses centered on ~600, 530, 470, 330, 200, and 90 cal yr BP. Synchronous fluctuations in Antarctic ice core chemistry strongly suggest that these variations are linked to changes in the westerlies. Partial inconsistencies among South African and South American records warn against the simplistic application of local-scale histories to the Southern Hemisphere as a whole. Nonetheless, these findings in general do support model projections of increasing aridity in austral winter rainfall zones with future warming.

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

2011-01-01

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

2012-01-01

18

Global warming and the regional persistence of a temperate-zone insect (Tenodera sinensis)  

Energy Technology Data Exchange (ETDEWEB)

Models based on the paleoecological record predict that animals in temperate regions will respond to global warming by migrating poleward to remain within their temperature tolerance ranges. The effect of global warming on invertebrates is of great concern because of their critical role in ecosystem structure and function. Migration poses a problem for many species because of their limited dispersal abilities. The life cycle of a typical temperature zone univoltine insect. Tenodera sinensis (Mantodea: Mantidae) is constrained by degree-days per season: too few prevent maturation before the killing frost in the autumn; too many allow egg hatch before a killing frost. We used field and laboratory observation on the life history and ecology of this species to predict the effect of global warming on the regional distribution of this insect by the end of the next century. Based on the simplified, best-case, biological assumptions of our model, the geographical range of T. sinensis in eastern North America would be compressed toward the northern part of its present contiguous regional distribution. This and other univoltine temperate species with long maturation periods and low vagility could face regional extinction if global warming predictions are accurate. 61 refs., 3 figs.

Rooney, T.P. [Indiana Univ. of Pennsylvania, Indiana, PA (United States); Smith, A.T. [Univ. of Delaware, Newark, DE (United States); Hurd, L.E. [Washington & Lee Univ., Lexington, VA (United States)

1996-07-01

19

Temperature sensitivity of calcium binding for parvalbumins from Antarctic and temperate zone teleost fishes.  

Science.gov (United States)

Parvalbumin (PV) is a soluble calcium-binding protein that is especially abundant in fast-twitch muscles of fish and other lower vertebrates. Despite its prevalence in ectothermic taxa, few data address the effects of temperature on PV binding function. In this study, calcium dissociation constants (KD) were measured as a function of temperature (0-25 degrees C) for PV from two Antarctic (Gobionotothen gibberifrons and Chaenocephalus aceratus) and two temperate zone fish species (Cyprinus carpio and Micropterus salmoides). Measurements by fluorometric competitive binding assay show that KD values for PVs from the Antarctic species were significantly higher at all assay temperatures and were less sensitive to temperature relative to carp and bass. However, estimates of KD are fundamentally similar for PVs from the Antarctic and temperate zone species when examined at their native physiological temperature. Variation in pH and ionic strength within a physiologically relevant range had only modest effects on KD. Thermodynamics of calcium binding to PV from G. gibberifrons and C. carpio was measured by isothermal microcalorimetry. When measured at 15 degrees C, the Gibbs free energy change (deltaG) was significantly greater for calcium binding to PV from G. gibberifrons than from carp (-43.4+/-1.5 kJ mol(-1) and -46.6+/-3.0 kJ mol(-1), respectively), and the relative contribution of entropy to deltaG for calcium binding to PV from the Antarctic species was about twice that of carp (deltaS=16.0+/-0.8 J degrees C(-1) mol(-1) for G. gibberifrons; deltaS=7.5+/-0.8 J degrees C(-1) mol(-1) for C. carpio). PMID:15748857

Erickson, Jeffrey R; Sidell, Bruce D; Moerland, Timothy S

2005-01-11

20

Temperature sensitivity of calcium binding for parvalbumins from Antarctic and temperate zone teleost fishes.  

UK PubMed Central (United Kingdom)

Parvalbumin (PV) is a soluble calcium-binding protein that is especially abundant in fast-twitch muscles of fish and other lower vertebrates. Despite its prevalence in ectothermic taxa, few data address the effects of temperature on PV binding function. In this study, calcium dissociation constants (KD) were measured as a function of temperature (0-25 degrees C) for PV from two Antarctic (Gobionotothen gibberifrons and Chaenocephalus aceratus) and two temperate zone fish species (Cyprinus carpio and Micropterus salmoides). Measurements by fluorometric competitive binding assay show that KD values for PVs from the Antarctic species were significantly higher at all assay temperatures and were less sensitive to temperature relative to carp and bass. However, estimates of KD are fundamentally similar for PVs from the Antarctic and temperate zone species when examined at their native physiological temperature. Variation in pH and ionic strength within a physiologically relevant range had only modest effects on KD. Thermodynamics of calcium binding to PV from G. gibberifrons and C. carpio was measured by isothermal microcalorimetry. When measured at 15 degrees C, the Gibbs free energy change (deltaG) was significantly greater for calcium binding to PV from G. gibberifrons than from carp (-43.4+/-1.5 kJ mol(-1) and -46.6+/-3.0 kJ mol(-1), respectively), and the relative contribution of entropy to deltaG for calcium binding to PV from the Antarctic species was about twice that of carp (deltaS=16.0+/-0.8 J degrees C(-1) mol(-1) for G. gibberifrons; deltaS=7.5+/-0.8 J degrees C(-1) mol(-1) for C. carpio).

Erickson JR; Sidell BD; Moerland TS

2005-02-01

 
 
 
 
21

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

Science.gov (United States)

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

22

Tropical Agroecosystems: These habitats are misunderstood by the temperate zones, mismanaged by the tropics.  

UK PubMed Central (United Kingdom)

I have listed some of the ways in which the lowland tropics are not such a warm and wonderful place for the farmer, some of the reasons why it may be unreasonable to expect him to cope with the problems, and some of the ways in which the temperate zones make his task more difficult. The tropics are very close to being a tragedy of the commons on a global scale (69, 103), and it is the temperate zone's shepherds and sheep who are among the greatest offenders (31). Given that the temperate zones have some limited amount of resources with which they are willing to repay the tropics, how can these resources best be spent? The first answer, without doubt, is education, and the incorporation of what is already known about the tropics into that education. Second should be the generation of secure psychological and physical resources for governments that show they are enthusiastic about the development of an SYTA. Third should be support of intensive research needed to generate the set of site-specific rules for specific, clearly identified SYTA's. The subject matter of youths' cultural programming is presumably determined by what they will need during the rest of their lives. A major component of this programming should be the teaching of the socioeconomic rules of a sustained-yield, nonexpanding economy, tuned to the concept of living within the carrying capacity of the country's or region's resources. Incorporating such a process into tropical school systems will cause a major upheaval, if for no other reason than that it will involve an evaluation of the country's resources, what standard of living is to be accepted by those living on them, and who is presently harvesting them. Of even greater impact, it will have to evaluate resources in terms of their ability to raise the standard of living by Y amount for X proportion of the people in the region, rather than in terms of their cash value on the world market. For such a change to be technologically successful, it will require a great deal of pantropical information exchange. This information exchange will cost a great deal of resource, not only in travel funds and support of on-site study, but in insurance policies for the countries that are willing to take the risk of trying to change from an exploitative agroecosystem to an SYTA. For such an experiment to be sociologically successful, it will require a complete change in tropical educational systems, from emphasizing descriptions of events as they now stand, to emphasizing analysis of why things happen the way they do. This will also be very expensive, not only in retreading the technology and mind-sets of current teaching programs, but in gathering the facts on why the tropics have met their current fate. There is a surfeit of biological and agricultural reports dealing with ecological experiments and generalities which suggest that such and such will be the outcome if such and such form of resource harvest is attempted. It is clear that human desiderata regarding a particular site are often radically different from the needs of the "average" wild animals and plants that formed the basis for such experiments and generalities. A finely tuned SYTA will come close to providing a unique solution for each region. The generalities that will rule it are highly stochastic. The more tropical the region, the more evenly weighted the suboutcomes will be, and thus the more likely each region will be to have a unique overall outcome. For example, it is easy to imagine four different parts of the tropics, each with the same kind of soil and the same climate, with four different, successful SYTA's, one based on paddy rice, one on shelterwood forestry, one on tourism, and one on shifting maize culture. A regional experiment station working holistically toward an SYTA is potentially one of the best solutions available. As currently structured, however, almost all tropical experiment stations are inadequate for such a mission. Most commonly they are structured around a single export crop such as coffee, sugar, rubber, cotton, ca

Janzen DH

1973-12-01

23

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

UK PubMed Central (United Kingdom)

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

van Vuuren AM; Chilibroste P

2013-03-01

24

Stronger biotic resistance in tropics relative to temperate zone: effects of predation on marine invasion dynamics.  

UK PubMed Central (United Kingdom)

Latitudinal patterns of nonnative species richness suggest fewer successful invasions in the tropics, relative to temperate regions. One main hypothesis for this pattern is that biotic resistance to invasion is stronger in the tropics than at higher latitudes. Biotic resistance can limit the distribution and abundance of nonnative species and, in extreme cases, can prevent establishment. We provide the first experimental test of this hypothesis, comparing the strength of biotic resistance in a tropical and a temperate marine ecosystem. Predation is one mechanism of biotic resistance, and since predation can be stronger at lower latitudes, we predicted that predation will serve to increase biotic resistance more in the tropics than at higher latitude. We conducted predator-exclusion experiments on marine epifaunal communities, a heavily invaded system, focusing on nonnative tunicates as a model fauna. The effect of predation on species richness of nonnative tunicates was more than three times greater at sites in tropical Panama than in temperate Connecticut, consistent with the prediction of stronger biotic resistance in the tropics. In Connecticut, predation reduced the abundance of one nonnative tunicate but did not affect the abundances of any other nonnative tunicate species, and no species were excluded from communities. In contrast, predation resulted in striking reductions in abundance and often exclusion of nonnative tunicates from experimental communities in Panama. If proved to be general, latitudinal differences in the biotic resistance of communities to nonnative species establishment may help explain emerging patterns of global invasions.

Freestone AL; Rutz GM; Torchin ME

2013-06-01

25

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

26

Silvicultural management in maintaining biodiversity and resistance of forests in Europe-temperate zone.  

Science.gov (United States)

In Europe temperate forests play a prominent role in timber production, nature protection, water conservation, erosion control and recreation. For centuries temperate forests in Europe have been affected by forest devastation and soil degradation. Applying great efforts to eliminate the severe wood shortage of those days, countermeasures were taken during the last 150 years by regenerating and tending highly productive forests. High growth rates and an increasing growing stock of these forests indicate that formerly stated goals have been successfully achieved. Coniferous species were often favoured because they were easy to establish and manage, and gave reason for high volume growth expectations. Today coniferous forests expand far beyond the limits of their natural ranges. These changes have been accompanied by a loss of biodiversity, a shift to nonsite adapted tree species and reduce the resistance against storms, snow, ice, droughts, insects and fungi. Some of these hazards were further intensified by the increasing average stand age, as well as in some areas by severe air pollution. Climatic fluctuations, especially changes in the frequency and intensity of extreme warm and dry climatic conditions and of heavy storms, had considerable impact on forest ecosystems. The changing demands of today require a widened scope of forest management. Society is asking for sustainable forestry emphasizing biodiversity and naturalistic forest management. It is of great economic and ecological relevance to know on which sites today's forests are most susceptible to climatic and other environmental changes and hazards. In those areas adjustments of management through a conversion the prevailing forests towards more site adapted mixed forests needs to be considered with priority. The high diversity in site conditions, ownership, economic and socio-cultural conditions require strategies adapted to the local and regional needs. Higher resistance of forests will increase economic and social benefits of forests and reduce the risks by maintaining sustainable forestry. PMID:12659804

Spiecker, Heinrich

2003-01-01

27

Silvicultural management in maintaining biodiversity and resistance of forests in Europe-temperate zone.  

UK PubMed Central (United Kingdom)

In Europe temperate forests play a prominent role in timber production, nature protection, water conservation, erosion control and recreation. For centuries temperate forests in Europe have been affected by forest devastation and soil degradation. Applying great efforts to eliminate the severe wood shortage of those days, countermeasures were taken during the last 150 years by regenerating and tending highly productive forests. High growth rates and an increasing growing stock of these forests indicate that formerly stated goals have been successfully achieved. Coniferous species were often favoured because they were easy to establish and manage, and gave reason for high volume growth expectations. Today coniferous forests expand far beyond the limits of their natural ranges. These changes have been accompanied by a loss of biodiversity, a shift to nonsite adapted tree species and reduce the resistance against storms, snow, ice, droughts, insects and fungi. Some of these hazards were further intensified by the increasing average stand age, as well as in some areas by severe air pollution. Climatic fluctuations, especially changes in the frequency and intensity of extreme warm and dry climatic conditions and of heavy storms, had considerable impact on forest ecosystems. The changing demands of today require a widened scope of forest management. Society is asking for sustainable forestry emphasizing biodiversity and naturalistic forest management. It is of great economic and ecological relevance to know on which sites today's forests are most susceptible to climatic and other environmental changes and hazards. In those areas adjustments of management through a conversion the prevailing forests towards more site adapted mixed forests needs to be considered with priority. The high diversity in site conditions, ownership, economic and socio-cultural conditions require strategies adapted to the local and regional needs. Higher resistance of forests will increase economic and social benefits of forests and reduce the risks by maintaining sustainable forestry.

Spiecker H

2003-01-01

28

[Seasonal variations of calorific values of Pinus koraiensis-broadleaved mixed forest litters and soil macrofauna in China temperate zone].  

UK PubMed Central (United Kingdom)

In this paper, the calorific values of Pinus koraiensis-broadleaved mixed forest litters and soil microfauna in China temperate zone were determined, with their seasonal variation patterns studied. The results showed that both the calorific values and their seasonal variation patterns were differed with the kinds of tree species litters and soil macrofauna in the mixed forest. The mean gross calorific value (GCV) of P. koraiensis litter was the highest (19.71 kJ x g(-1)), followed by Betula costata (18.22 kJ x g(-1)), Tilia amurensis (18.13 kJ x g(-1)), mixed litter (17.91 kJ x g(-1)), Fraxinus mandshurica (16.94 kJ x g(-1)), and Acer mono (16.25 kJ x g(-1)). With the decomposition of litter, the GCV of P. koraiensis and A. mono litters decreased, while that of F. mandshurica litter had little change. The GCV of T. amurensis and B. costata litters presented an increasing trend in the next year of decomposition. Among the marofauna, scolopendra had the highest GCV (22.07 kJ x g(-1)), followed by earthworm (16.72 kJ x g(-1)) and diplopod (13.28 kJ x g(-1)). Earthworm and diplopod had the identical seasonal variation pattern of GCV, while scolopendra was different from them. There was no significant relationship between the seasonal variation of GCV in litters and soil macrofauna.

Yin XQ; Xin WD; Qi YH

2007-04-01

29

[Seasonal variations of calorific values of Pinus koraiensis-broadleaved mixed forest litters and soil macrofauna in China temperate zone].  

Science.gov (United States)

In this paper, the calorific values of Pinus koraiensis-broadleaved mixed forest litters and soil microfauna in China temperate zone were determined, with their seasonal variation patterns studied. The results showed that both the calorific values and their seasonal variation patterns were differed with the kinds of tree species litters and soil macrofauna in the mixed forest. The mean gross calorific value (GCV) of P. koraiensis litter was the highest (19.71 kJ x g(-1)), followed by Betula costata (18.22 kJ x g(-1)), Tilia amurensis (18.13 kJ x g(-1)), mixed litter (17.91 kJ x g(-1)), Fraxinus mandshurica (16.94 kJ x g(-1)), and Acer mono (16.25 kJ x g(-1)). With the decomposition of litter, the GCV of P. koraiensis and A. mono litters decreased, while that of F. mandshurica litter had little change. The GCV of T. amurensis and B. costata litters presented an increasing trend in the next year of decomposition. Among the marofauna, scolopendra had the highest GCV (22.07 kJ x g(-1)), followed by earthworm (16.72 kJ x g(-1)) and diplopod (13.28 kJ x g(-1)). Earthworm and diplopod had the identical seasonal variation pattern of GCV, while scolopendra was different from them. There was no significant relationship between the seasonal variation of GCV in litters and soil macrofauna. PMID:17615867

Yin, Xiu-Qin; Xin, Wei-Dong; Qi, Yan-Hong

2007-04-01

30

Vascular plant species richness along environmental gradients in a cool temperate to sub-alpine mountainous zone in central Japan.  

UK PubMed Central (United Kingdom)

In order to clarify how vegetation types change along the environmental gradients in a cool temperate to sub-alpine mountainous zone and the determinant factors that define plant species richness, we established 360 plots (each 4 × 10 m) within which the vegetation type, species richness, elevation, topographic position index (TPI), slope inclination, and ground light index (GLI) of the natural vegetation were surveyed. Mean elevation, TPI, slope inclination, and GLI differed across vegetation types. Tree species richness was negatively correlated with elevation, whereas fern and herb species richness were positively correlated. Tree species richness was greater in the upper slope area than the lower slope area, whereas fern and herb species richness were greater in the lower slope area. Ferns and trees species richness were smaller in the open canopy, whereas herb species richness was greater in the open canopy. Vegetation types were determined firstly by elevation and secondary by topographic configurations, such as topographic position, and slope inclination. Elevation and topography were the most important factors affecting plant richness, but the most influential variables differed among plant life-form groups. Moreover, the species richness responses to these environmental gradients greatly differed among ferns, herbs, and trees.

Tsujino R; Yumoto T

2013-03-01

31

Holocene climate variability in the winter rainfall zone of South Africa  

Science.gov (United States)

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 cal years BP) most likely in response to a northward shift of the austral westerlies. Wet phases and strengthened coastal water upwellings are companied by a decrease of Agulhas water leakage into the South Atlantic and a reduced dust incursion over Antarctica, as indicated in previous studies. A continuous aridification trend in the WRZ and a weakening of the southern Benguela Upwelling System (BUS) between 9000 and 5500 cal years BP parallel with increase of dust deposition over Antarctica and an enhanced leakage of warm Agulhas water into the eastern South Atlantic. The temporal relationship between precipitation changes in the WRZ, the thermal state of the coastal surface water, and leakage of warm water in the South Atlantic, and variation of dust incursion over Antarctica suggests a causal link that most likely was related to latitudinal shifts of the Southern Hemisphere westerlies. Our results of the mid-Holocene time interval may serve as an analogue to a possible long-term consequence of the current and future southward shift of the westerlies. Furthermore, warming of the coastal surface water as a result of warm Agulhas water incursion into the southern BUS may affect coastal fog formation.

Weldeab, S.; Stuut, J.-B. W.; Schneider, R. R.; Siebel, W.

2013-10-01

32

Holocene climate variability in the Winter Rainfall Zone of South Africa  

Science.gov (United States)

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

Weldeab, S.; Stuut, J.-B. W.; Schneider, R. R.; Siebel, W.

2013-05-01

33

Experimental and field studies on some biological characteristics of Plasmodium vivax isolated from tropical and temperate zones of China.  

UK PubMed Central (United Kingdom)

OBJECTIVE: To clarify some biological behaviors of Plasmodium vivax including the periodical infectivity of gametocytes for mosquitoes, the prepatent period, the incubation period, the relapse patterns and their relationship. METHODS: Laboratory reared Anopheles sinensis were fed through fetal membrane on blood from patients naturally infected with vivax malaria. After feeding at different hours, the engorged mosquitoes kept in the insectarium were dissected 5-7 days later. The percentage of mosquitoes infected and the mean number of oocysts per gut were taken as criteria of the viability of the gametocytes. The healthy volunteers artificially infected by mosquito bite or quantitative inoculation of sporozoites were treated with 1.5 g chloroquine base alone before and after the first and subsequent onset of fever to detect the natural course of disease in human body. RESULTS: The infection in mosquitoes can readily be divided into upward, peak, downward and non-infective period. The infectivity reached a peak at interschizogony period and fell to low level at the time when schizogony occurred. The short incubation period was frequently observed in persons bitten by 10 infected mosquitoes or 10 000 sporozoites inoculated and the long incubation period was constantly recorded in cases receiving 100 sporozoites. When one mosquito was allowed to feed on volunteers or 1 000 sporozoites were injected, the incubation period may be short or prolonged. CONCLUSIONS: The 48-hour cycle in the infectivity of gametocyte for mosquitoes was demonstrated and the peak of oocyst production preceded the peak of parasitaemia by 1 to 3 days. Prompt radical treatment is extra important. Since the incubation period is variable depending on the number of sporozoites inoculated and the tropical versus temperate zone malaria is not all-inclusive, the classification of tertian malaria might be reconsidered.

Yang B

1996-04-01

34

Effects of ambient UV-B radiation on the above-ground biomass of seven temperate-zone plant species.  

UK PubMed Central (United Kingdom)

Variations in the amount of solar ultraviolet-B radiation (UV-B) reaching the biosphere may alter productivity in non-agricultural plants. We examined how ambient levels of UV-B modify the biomass of seven temperate-zone species including three grass species (Echinochloa crusgalli, Setaria faberi, Elymus virginicus), three forbs (Verbascum blattaria, Lactuca biennis, Oenothera parviflora), and one tree species (Quercus rubra). Plants were grown outside in enclosures near Morgantown, WV, USA (39 degrees N, 79 degrees W) for one season under near-ambient or no UV-B conditions. The different levels of UV-B were achieved using filters which differentially transmit UV-B irradiance. There was a trend towards reduced above-ground biomass in L. Biennis (14%) and significantly increased above-ground biomass in O. parviflora (10.2%) under ambient UV-B. The partitioning of biomass between individual plant parts was altered by ambient UV-B in O. parviflora. Leaf biomass was significantly increased (18%), and there were trends toward increased stem (6.7%) and reproductive (9%) biomass. In addition to biomass stimulations, O. parviflora grew significantly taller (5.3%) under ambient UV-B. This study provides evidence that some non-agricultural plants exhibit species-specific growth responses to variable UV-B, with short-lived forbs appearing to be the most sensitive. If the biomass and morphological alterations observed for the forbs in this study were to persist over several years, they might modify population dynamics, competitive interactions, and productivity in ecosystems as UV-B levels fluctuate in the future.

Cybulski WJIII; Peterjohn WT

1999-11-01

35

Control of Saharan mineral dust transport to Barbados in winter by the Intertropical Convergence Zone over West Africa  

Science.gov (United States)

The reasons for the inter-annual variability of dust transport from the Sahara across the Atlantic are not well-understood. Here we address this issue by defining three new climate indices that capture the position and intensity of the zone of near-surface convergence over West Africa, a part of the global Intertropical Convergence Zone (ITCZ). We then relate these indices to a 38-year record of mineral dust concentrations at Barbados focusing on the winter season. The results show that the latitudinal displacement of the ITCZ over West Africa and the dust load in Barbados are statistically significantly correlated with a correlation coefficient ofr= -0.69. A southward movement of the ITCZ corresponds to an increased dust load at Barbados. This correlation represents an improvement upon previous results, which focused on traditional teleconnection indices such as the North Atlantic Oscillation or the El-Niño-Southern Oscillation. From analyzing composites of wind and precipitation we conclude that for the winter season, the inter-annual variability of the Barbados dust load is related to changes in near-surface northeasterly winds in semi-arid regions in North Africa coincident with the movement of the ITCZ. Changes in precipitation appear to only play a minor role.

Doherty, O. M.; Riemer, N.; Hameed, S.

2012-10-01

36

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)

[en] 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)

1984-01-01

37

A tempering column  

UK PubMed Central (United Kingdom)

The invention concerns an apparatus (1) having a cylindrical tempering column for continuous tempering of a cacao-butter-containing or other fat-containing, chocolate-like mass pumped therethrough, which tempering column further comprise a plurality of interconnected mass chambers (2), which are separated by intermediary heat exchange chambers (3), and which mass chambers (2) further comprise mixing and stirring elements (5), which are rotated by the action of a common, central drive shaft (6) arranged in the column, whereby said mixing and stirring elements (5) comprise a disc shaped part. Hereby it has been determined that non-active zones of the area wiped by the stirring elements can be transformed into active zones for shearing or for the flow of mass.

Haslund Henning

38

Comparison of Searching Behaviour of Two Aphelinid Parasitoids of the Greenhouse Whitefly, Trialeurodes vaporariorum under Summer vs. Winter Conditions in a Temperate Climate  

UK PubMed Central (United Kingdom)

Searching behaviour of two aphelinid parasitoids, Encarsia formosa Gahan and Eretmocerus eremicus Rose and Zolnerowich, was compared in a controlled environment under simulated summer [high light intensity (83 ± 1 W/m²), and 24 ± 1°C] and winter [low light intensity (11 ± 0.5 W/m²), and 20 ± 1°C] greenhouse conditions on tomato leaflets, with and without a single 3rd instar whitefly host, Trialeurodes vaporariorum (Westwood), within a 4-cm tomato leaflet arena. Residence time of both parasitoid species was longer on infested leaflets vs. clean leaflets, and longer under winter than summer conditions. When parasitoids encountered a host on infested leaflets, residence time increased. In all cases, residence time of E. formosa was longer that of E. eremicus. Proportion of time spent searching (i.e. antennating leaf surface while walking or standing still) was longer on clean vs. infested leaflets for both E. formosa and E. eremicus. Walking speed by E. eremicus on clean leaflets was faster than E. formosa under both summer and winter conditions. Host handling time and proportion of host acceptance did not vary among parasitoids. These findings suggest that E. eremicus could be more efficient in host finding on tomato leaflets than E. formosa over all seasons, especially in the winter when natural light is limiting and where daylight temperatures are >=20°C.

Zilahi-Balogh GMG; Shipp JL; Cloutier C; Brodeur J

2009-03-01

39

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

40

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

 
 
 
 
41

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

UK PubMed Central (United Kingdom)

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.

Sasakawa K

2010-10-01

42

Carbon Dioxide Effects Research and Assessment Program. The role of temperate zone forests in the world carbon cycle: problem definition and research needs  

Energy Technology Data Exchange (ETDEWEB)

The continuing rise in the CO/sub 2/ content of the atmosphere has produced concern that in the next half-century, climatic, ecological and societal effects may occur throughout the world which will not easily be reversed. This prospect has encouraged a critical assessment of the many elements of the global carbon cycle and the influence of man on it. The role of the terrestrial biosphere has been underscored by recent evidence that reduction of the world's biota may be adding as much or more carbon to the atmosphere as combustion of fossil fuels. The diversity of world ecosystems, and the lack of data on carbon content in many of them, have led to different interpretations of how much the terrestrial biosphere contributes to carbon accumulation in the atmosphere. A detailed review is needed of the principal elements of biospheric influence on the carbon cycle, of where the accumulating atmospheric carbon is originating, and of the options there may be to control it. The Office of Carbon Dioxide Effects Research and Assessment of the US Department of Energy has funded The Institute of Ecology to evaluate three terrestrial biospheric components which may be important in the world carbon cycle. These components are: the temperate zone forest, particularly over the past 100 years; organic soils of the world; and freshwater systems subject to eutrophication. From 10 to 12 researchers have participated in each panel. Data review, problem definition and recommendations for research have been the focus in each workshop. The results reported here cover the temperate forest component.

Amentano, T.V.; Hett, J. (ed.)

1980-02-01

43

The discharge front structure in coastal zone of the Laptev Sea in winter season  

Science.gov (United States)

In the Arctic region the discharge front is poor studied phenomenon, especially in cold season. We investigated thermohaline structure in the south-eastern part of the Laptev Sea (the Buor-Khaya Bay) where front has been forming under the ice cover. It is identified by strong horizontal temperature and salinity gradients. Front location and its dimension are under the influence of the Lena River discharge. The front dynamics resulted in specifics of vertical thermohaline structure, which is characterized by baroclinic and thermoclinic constituents. In a short distance from the river mouth the front is baroclinic (isotherms and isohalines remain parallel to each other). Another type of front (thermoclinic) is formed at the periphery of the front (isohalines intersect isotherms at an angle of up to 90°). The first mechanism of thermoclinicity is isopycnic convergence of river water in lower horizons because of its cooling near the ice. The second mechanism works at the periphery of the front, where horizontal stratification is weaken, and frontal convergence is resulted in isopycnic intrusions of cold water under the relatively warm fresh water. The intrusion's cross section in the Bay made about 50-85 km and thickness varied from 3-5 up to 15m depending on the Lena River discharge. The temperature of intrusions is lower than at bottom water. The interleaving cold and warm freshened water inside the intrusion is a result of double diffusion process. Water of the intrusion is enriched with dissolved oxygen and facilitates to ventilation of water in the coastal zone under the ice. The calculated heat content of bottom water testifies about its origin from the outer shelf of the Laptev Sea while the T-S characteristics of intrusion is close connected to the inner shelf.

Savelieva, Nina; Salyuk, Anatoly

2010-05-01

44

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

UK PubMed Central (United Kingdom)

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.

Hanson RB; Lowery HK

1985-05-01

45

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

46

Evaluation of energy efficient design strategies for different climatic zones: Comparison of thermal performance of buildings in temperate-humid and hot-dry climate  

Energy Technology Data Exchange (ETDEWEB)

Since the Kyoto protocol signed in December 1997 the majority of governments around the world have committed themselves to reducing the emission of the greenhouse gases. Thus, efficient use of energy and sustainability has become a key issue for the most energy policies. Sustainability and energy saving terms take place in building construction industry too since buildings are one of the most significant energy consumers. It is known that heating energy demand of a building has a great rate in building total energy consumption. In addition to that, the most of the heating energy has been lost from building envelope. TS 825, Heating Energy Conservation Standard for Buildings in Turkey, aims the reducing of heat loss in buildings through the envelope. But within buildings, one of the fastest growing sources of new energy demand is cooling and especially in hot-humid and hot-dry climatic parts of Turkey the cooling season is much longer than the heating season. Moreover in hot-dry climate heat storage capacity of the envelope becomes more important issue than heat insulation for energy efficiency of the building. Since the Turkish standard is considering only heating energy conservation by using degree-day concept, Istanbul and Mardin are considered in the same zone, however those are in temperate-humid and hot-dry climatic zones, respectively. In this study energy efficient design strategies for these climatic zones have been explained and thermal performance of two buildings, which are constructed according to the TS 825 in Mardin and Istanbul cities were evaluated to show the importance of thermal mass in hot-dry climates. (author)

Yilmaz, Z. [Faculty of Architecture, Istanbul Technical University, Taskisla, Taksim (Turkey)

2007-07-01

47

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 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 climáticas, estresses e problemas de adaptação, desenvolveu-se este trabalho, no Laboratório de Fisiologia Vegetal da Embrapa Clima Temperado, com o objetivo de d (more) escrever 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 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 me (more) thodology 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.

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

2005-04-01

48

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; Flávio Gilberto Herter; Valtair Veríssimo; Geraldo Chavarria; João Peterson Pereira Gardin; Ângela Diniz Campos

2005-01-01

49

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

50

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

Energy Technology Data Exchange (ETDEWEB)

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 {sup 15}N 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.

Zhou Shunli [Key Laboratory of Crop Cultivation and Farming System, Ministry of Agriculture, College of Agronomy and Biotechnology, China Agricultural University, 2 West Yuanmingyuan Road, Beijing 100094 (China)], E-mail: zhoushl@cau.edu.cn; Wu Yongcheng [Key Laboratory of Crop Cultivation and Farming System, Ministry of Agriculture, College of Agronomy and Biotechnology, China Agricultural University, 2 West Yuanmingyuan Road, Beijing 100094 (China); College of Agronomy, Si Chuan Agricultural University, Yaan 625014 (China); Wang Zhimin [Key Laboratory of Crop Cultivation and Farming System, Ministry of Agriculture, College of Agronomy and Biotechnology, China Agricultural University, 2 West Yuanmingyuan Road, Beijing 100094 (China); Lu Laiqing; Wang Runzheng [Wuqiao Experimental Station, China Agricultural University, Hebei 061802 (China)

2008-04-15

51

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.

2008-01-01

52

Prevalence, Mass, and Glucose-Uptake Activity of 18F-FDG-Detected Brown Adipose Tissue in Humans Living in a Temperate Zone of Italy  

Science.gov (United States)

Background The 18F-fluorodeoxyglucose (18F-FDG)-detected brown adipose tissue (BAT), is enhanced by cold stimulus and modulated by other factors that still have to be disentangled. We investigated the prevalence, mass, and glucose-uptake activity of 18F-FDG-detected BAT in a population of adults living in the temperate climatic zone of the Rome area. Methods and Findings We retrospectively analyzed 6454 patients who underwent 18F-FDG positron emission tomography/computed tomography (PET/CT) examinations. We found 18F-FDG BAT in 217 of the 6454 patients (3.36%). Some of them underwent more than one scan and the positive scans were 278 among 8004 (3.47%). The prevalence of patients with at least one positive scan was lower in men (1.77%; 56 of 3161) compared with women (4.88%; 161 of 3293). The BAT positive patients were most frequently younger, thinner and with lower plasma glucose levels compared with BAT negative patients. The amount of BAT in the defined region of interest, the activity of BAT and the number of positive sites of active BAT were similar in both sexes. The prevalence of patients with 18F-FDG positive PET/CT was highest in December-February, lower in March-May and September-November, and lowest in June-August and was positively correlated with night length and negatively correlated with ambient temperature. Changes in day length and variations of temperature, associated with the prevalence of positive BAT patients. Among the patients who had multiple scans, outdoor temperature was significantly lower and day length was shorter on the occasion when BAT was detected. Conclusions This study identifies day length, outdoor temperature, age, sex, BMI, and plasma glucose levels as major determinants of the prevalence, mass, and activity of 18F-FDG-detected BAT.

Persichetti, Agnese; Sciuto, Rosa; Rea, Sandra; Basciani, Sabrina; Lubrano, Carla; Mariani, Stefania; Ulisse, Salvatore; Nofroni, Italo; Maini, Carlo Ludovico; Gnessi, Lucio

2013-01-01

53

Typical patterns of PBL structure and dynamics in transitional ocean-continent zone in summer and winter in Far East region  

Science.gov (United States)

The paper is connected with planetary boundary layer (PBL) the lowermost part of the atmosphere its structure and dynamics investigations in the Far Eastern coastal zone in winter and summer. The data have been analyzed were obtained by means of aerosol polarization lidar. Mean values of PBL height, top of the convective layer and mean height of the nocturnal layer were presented. Well-developed nocturnal convection in the PBL was analyzed and explained. On the example of several summer days specific features of the PBL structure and dynamics are identified, presented and analyzed. Maximal values of breeze circulation heights are also presented.

Shmirko, Konstantin A.; Pavlov, Andrey N.; Stolyarchuk, Sergey Y.; Mayor, Alexander Y.; Bukin, Oleg A.

2012-11-01

54

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

Directory of Open Access Journals (Sweden)

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

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

2004-01-01

55

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

International Nuclear Information System (INIS)

[en] 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)

56

Summer Dormancy in Perennial Temperate Grasses  

Digital Repository Infrastructure Vision for European Research (DRIVER)

• Background and Aims Dormancy has been extensively studied in plants which experience severe winter conditions but much less so in perennial herbaceous plants that must survive summer drought. This paper reviews the current knowledge on summer dormancy in both native and cultivated perennial temper...

VOLAIRE, FLORENCE; NORTON, MARK

57

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

UK PubMed Central (United Kingdom)

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 MU; Widmer S; Korner-Nievergelt F; Naef-Daenzer B

2013-02-01

58

Seasonal dynamics of arboreal spider diversity in a temperate forest.  

UK PubMed Central (United Kingdom)

Measuring and estimating biodiversity patterns is a fundamental task of the scientist working to support conservation and inform management decisions. Most biodiversity studies in temperate regions were often carried out over a very short period of time (e.g., a single season) and it is often-at least tacitly-assumed that these short-term findings are representative of long-term general patterns. However, should the studied biodiversity pattern in fact contain significant temporal dynamics, perhaps leading to contradictory conclusions. Here, we studied the seasonal diversity dynamics of arboreal spider communities dwelling in 216 European beeches (Fagus sylvatica L.) to assess the spider community composition in the following seasons: two cold seasons (I: November 2005-January 2006; II: February-April) and two warm seasons (III: May-July; IV: August-October). We show that the usually measured diversity of the warm season community (IV: 58 estimated species) alone did not deliver a reliable image of the overall diversity present in these trees, and therefore, we recommend it should not be used for sampling protocols aimed at providing a full picture of a forest's biodiversity in the temperate zones. In particular, when the additional samplings of other seasons (I, II, III) were included, the estimated species richness nearly doubled (108). Community I possessed the lowest diversity and evenness due to the harsh winter conditions: this community was comprised of one dominant species together with several species low in abundance. Similarity was lowest (38.6%) between seasonal communities I and III, indicating a significant species turnover due to recolonization, so that community III had the highest diversity. Finally, using nonparametric estimators, we found that further sampling in late winter (February-April) is most needed to complete our inventory. Our study clearly demonstrates that seasonal dynamics of communities should be taken into account when studying biodiversity patterns of spiders, and probably forest arthropods in general.

Hsieh YL; Linsenmair KE

2012-04-01

59

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; Benjamin T. Hutchins; Benjamin F. Schwartz

2013-01-01

60

Cell mediated immunity in Antarctic wintering personnel; 1984-1992.  

UK PubMed Central (United Kingdom)

Cell-mediated immune responses were studied in 12 Antarctic and sub-Antarctic wintering groups at quarterly intervals over the period 1984-1992, using the cutaneous CMI Multitest. These populations are among the most isolated on earth. While the sub-Antarctic population at Macquarie Island had levels of responsiveness and hypoergy (9%) comparable to healthy populations in temperate zones, the Antarctic Continental group showed a level of hypoergy of 36%. There was no seasonal variation in the pattern of responses. It is concluded that the extreme and isolated environment and stress factors are responsible for the decreased immunological responsiveness but the mechanisms are presently unclear. On review, one factor appears to be perceived anxiety. The high rate of hypoergy in Antarctica, where medical care is limited, may have health implications. These groups provide an excellent analogue for immunological investigations in longer term space flight.

Muller HK; Lugg DJ; Quinn D

1995-08-01

 
 
 
 
61

Winter survival and deacclimation of perennials under warming climate: physiological perspectives.  

UK PubMed Central (United Kingdom)

Appropriate timing and rate of cold deacclimation and the ability to reacclimate are important components of winter survival of perennials in temperate and boreal zones. In association with the progressive increase in atmospheric CO?, temperate and boreal winters are becoming progressively milder, and temperature patterns are becoming irregular with increasing risk of unseasonable warm spells during the colder periods of plants' annual cycle. Because deacclimation is mainly driven by temperature, these changes pose a risk for untimely/premature deacclimation, thereby rendering plant tissue vulnerable to freeze-injury by a subsequent frost. Research also indicates that elevated CO? may directly impact deacclimation. Hence, understanding the underlying cellular mechanisms of how deacclimation and reacclimation capacity are affected by changes in environmental conditions is important to ensure winter survival and the sustainability of plant sources under changing climate. Relative to cold acclimation, deacclimation is a little studied process, but the limited evidence points to specific changes occurring in the transcriptome and proteome during deacclimation. Loss of freezing tolerance is additionally associated with substantial changes in cell/tissue-water relations and carbohydrate metabolism; the latter also impacted by temperature-driven, altered respiratory metabolism. This review summarizes recent progress in understanding the physiological mechanisms of deacclimation and how they may be impacted by climate change.

Pagter M; Arora R

2013-01-01

62

Winter survival and deacclimation of perennials under warming climate: physiological perspectives  

UK PubMed Central (United Kingdom)

Appropriate timing and rate of cold deacclimation and the ability to reacclimate are important components of winter survival of perennials in temperate and boreal zones. In association with the progressive increase in atmospheric CO?, temperate and boreal winters are becoming progressively milder, and temperature patterns are becoming irregular with increasing risk of unseasonable warm spells during the colder periods of plants' annual cycle. Because deacclimation is mainly driven by temperature, these changes pose a risk for untimely/premature deacclimation, thereby rendering plant tissue vulnerable to freeze?injury by a subsequent frost. Research also indicates that elevated CO? may directly impact deacclimation. Hence, understanding the underlying cellular mechanisms of how deacclimation and reacclimation capacity are affected by changes in environmental conditions is important to ensure winter survival and the sustainability of plant sources under changing climate. Relative to cold acclimation, deacclimation is a little studied process, but the limited evidence points to specific changes occurring in the transcriptome and proteome during deacclimation. Loss of freezing tolerance is additionally associated with substantial changes in cell/tissue?water relations and carbohydrate metabolism; the latter also impacted by temperature?driven, altered respiratory metabolism. This review summarizes recent progress in understanding the physiological mechanisms of deacclimation and how they may be impacted by climate change.

Pagter M; Arora R

2013-01-01

63

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

DEFF Research Database (Denmark)

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.

Hahn, Ina H; Grynderup, Matias

2011-01-01

64

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; CHRISTOPHER H. LUSK

2011-01-01

65

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 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 transición entre la región mediterránea y templada de Chile. Pretendimos dilucidar si las especies sobreviven en forma diferencial a la disminución estacional en la dispo (more) nibilidad 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 (more) 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.

PARADA, TERESA; LUSK, CHRISTOPHER H.

2011-01-01

66

A tempering apparatus  

UK PubMed Central (United Kingdom)

An apparatus (1) having a cylindrical tempering column for continuous tempering of cacao butter containing or other fat-containing, chocolate-like mass pumped therethrough, which tempering column further comprise a plurality of interconnected mass chambers (2), which are separated by intermediary heat exchange chambers (3), and which mass chambers (2) further comprise mixing and stirring elements (5), which are rotated by the action of a common, central drive shaft (6) arranged in the column, said mixing and stirring elements (5) comprise a disc shaped part, further comprising clearances between the disc shaped parts (5) and surfaces of the heat exchange chambers (3) wherein, the clearances increases with increasing radius of the disc shaped parts. Hereby is obtained that the shear gradient reaches a more constant level than by the prior art and consequently the tempered chocolate constitutes of a higher number as well as a more constant amount of stable beta5 crystals than before.

Haslund Henning

67

Controlling Effects of Irradiance and Heterotrophy on Carbon Translocation in the Temperate Coral Cladocora caespitosa  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Temperate symbiotic corals, such as the Mediterranean species Cladocora caespitosa, live in seasonally changing environments, where irradiance can be ten times higher in summer than winter. These corals shift from autotrophy in summer to heterotrophy in winter in response to light limitation of the ...

Tremblay, Pascale; Ferrier-Pagès, Christine; Maguer, Jean François; Rottier, Cécile; Legendre, Louis; Grover, Renaud

68

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

UK PubMed Central (United Kingdom)

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

Hanya G; Tsuji Y; Grueter CC

2013-04-01

69

Winter leaf reddening in 'evergreen' species.  

UK PubMed Central (United Kingdom)

Leaf reddening during autumn in senescing, deciduous tree species has received widespread attention from the public and in the scientific literature, whereas leaf reddening in evergreen species during winter remains largely ignored. Winter reddening can be observed in evergreen herbs, shrubs, vines and trees in Mediterranean, temperate, alpine, and arctic regions, and can persist for several months before dissipating with springtime warming. Yet, little is known about the functional significance of this colour change, or why it occurs in some species but not others. Here, the biochemistry, physiology and ecology associated with winter leaf reddening are reviewed, with special focus on its possible adaptive function. Photoprotection is currently the favoured hypothesis for winter reddening, but alternative explanations have scarcely been explored. Intraspecific reddening generally increases with sunlight incidence, and may also accompany photosynthetic inferiority in photosynthetically 'weak' (e.g. low-nitrogen) individuals. Red leaves tend to show symptoms of shade acclimation relative to green, consistent with a photoprotective function. However, winter-red and winter-green species often cohabitate the same high-light environments, and exhibit similar photosynthetic capacities. The factors dictating interspecific winter leaf colouration therefore remain unclear. Additional outstanding questions and future directions are also highlighted, and possible alternative functions of winter reddening discussed.

Hughes NM

2011-05-01

70

Remotely estimating aerial N status of phenologically differing winter wheat cultivars grown in contrasting climatic and geographic zones in China and Germany  

UK PubMed Central (United Kingdom)

Red light based broadband vegetation indices are widely applied to derive aerial nitrogen (N) status parameters. With the advance of growth stages, however, crop canopy structure and aerial biomass will vary greatly, which negatively influences the relationships between spectral indices and the crop canopy N status. The current research aimed to assess the performance of red edge based vegetation indices, derived from simulated broadband WorldView-2 data, to remotely sense aerial N concentration and uptake in winter wheat (Triticum aestivum L.). Six experiments with different N rates for five German cultivars and four Chinese cultivars of winter wheat were conducted in southeast Germany and in the North China Plain from 2007 to 2010. The results showed that aerial biomass strongly affected the relationships between broadband vegetation indices and aerial N concentration before the heading stage. Normalising by using the planar domain index approach significantly improved the prediction power of red edge dependent broadband vegetation indices in estimating aerial N status. The two-dimensional broadband canopy chlorophyll content index (CCCI) and a newly proposed nitrogen planar domain index (NPDI) involving the WorldView-2 satellite red edge region were found to be more stable and better predictors than traditional red light based broadband vegetation indices in estimating aerial N concentration after the heading stage and in assessing aerial N uptake before the heading stage. The findings from this study may be useful for managing the application of N fertiliser for winter wheat in Zadoks growth stages 30–55 and in indirectly monitoring aerial N content in Zadoks growth stages 59–75 at landscape scales.

Li F; Mistele B; Hu Y; Yue X; Yue S; Miao Y; Chen X; Cui Z; Meng Q; Schmidhalter U

2012-10-01

71

Isotopic biogeochemistry of carbon in recent and fossil mammal bones and teeth from cold temperate areas. Biogeochimie isotopique du carbone dans les os et les dents de mammiferes actuels et fossiles de zones froides et temperees  

Energy Technology Data Exchange (ETDEWEB)

The difference between [sup 13]C isotopic abundances in bone organic matter (collagen) and the mineral phase (carbonate hydroxylapatite) is used for the determination of the trophic level of the animal, especially on fossil samples. This difference is greater for herbivore mammals from cold and temperate areas than for South African herbivore mammals studied previously (0.84 [+-] 0.14% versus 0.68 [+-] 0.14% respectively). This larger value should be used in the interpretation of isotopic abundances of [sup 13]C in fossil mammals from temperate and arctic areas.

Bocherens, H.; Mariotti, A. (Paris-6 Univ., 75 (France))

1992-10-01

72

Winter Depression  

Science.gov (United States)

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

73

Edge microclimate of temperate woodlands as affected by adjoining land use  

UK PubMed Central (United Kingdom)

While edge microclimates are well described for closed forests, they remain under-examined in more sparse vegetation types like the temperate woodlands of south-eastern Australia. This limits predictions of edge effects on remnant vegetation in cleared agricultural landscapes, and of changes in these effects with reforestation. Using fixed and roving weather stations, we examined influences on temperate woodland microclimate of adjoining land use (agriculture versus tree plantation), distance from edge (0-150m), and woodland structural attributes (canopy openness, stem density and basal area). Shading by plantations significantly decreased temperatures and vapour pressure deficit (VPD) at woodland edges in winter (up to 0.8°C and 75Pa relative to agricultural edges). However, this effect was reversed in the non-winter months, when daytime temperatures and VPD were generally greater at plantation than agricultural edges (up to 0.5°C and 300Pa). This was the opposite of edge-type effects recorded for closed-forest types, and was explained by lower wind speeds at plantation edges, which led to the accumulation of heat in the 25m firebreak between the two land uses. A similar 'dead zone' also apparently contributed to cooler, moister night-time conditions at plantation edges. Consistent with closed forests, and irrespective of edge type and season, we measured a depth of edge influence of 40-50m for daytime temperature and VPD. However, magnitude of edge influence (ca. 0.5°C and 100Pa) was much less than in closed forests, and woodland interiors were warmer and drier than edges, whereas closed-forest interiors are usually cooler and moister than edges. This unique microclimate gradient into woodlands was explained both by decreasing wind speeds, and by positive relationships of temperature and VPD with basal area and stem density, highlighting the role of sub-canopy heat sinks like tree trunks in regulating interior microclimates of sparse vegetation types.

Wright ThomasE; Kasel Sabine; Tausz Michael; Bennett LaurenT

2010-07-01

74

On intergranular tempered martensite embrittlement  

Energy Technology Data Exchange (ETDEWEB)

Tempering of martensitic alloy steels is generally required to impart adequately high toughness instead of brittleness in the as-quenched state. When hardened steels are tempered in the range of 250--400 C, however, a loss in toughness can occur in spite of the decrease in strength with increasing tempering temperature. This phenomenon is referred to as tempered martensite embrittlement (TME). In this study, the intergranular type of TME has been analyzed in terms of impact toughness and fracture behavior on isothermal and isochronal tempering. The alloy systems chosen are the commercial 4140 and 4340 steels. The 4340 steel contains the alloying element Ni which enhances the intrinsic toughness.

Lee, K.B.; Yoon, S.H.; Hong, S.I.; Kwon, H. [Kookmin Univ., Seoul (Korea, Republic of)

1995-04-15

75

Off-season uptake of nitrogen in temperate heath vegetation  

DEFF Research Database (Denmark)

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

Andresen, Louise Christoffersen; Michelsen, Anders

2004-01-01

76

Multicanonical Parallel Tempering  

CERN Multimedia

We present a novel implementation of the parallel tempering Monte Carlo method in a multicanonical ensemble. Multicanonical weights are derived by a self-consistent iterative process using a Boltzmann inversion of global energy histograms. This procedure gives rise to a much broader overlap of thermodynamic-property histograms; fewer replicas are necessary in parallel tempering simulations, and the acceptance of trial swap moves can be made arbitrarily high. We demonstrate the usefulness of the method in the context of a grand-multicanonical ensemble, where we use multicanonical simulations in energy space with the addition of an unmodified chemical potential term in particle-number space. Several possible implementations are discussed, and the best choice is presented in the context of the liquid-gas phase transition of the Lennard-Jones fluid. A substantial decrease in the necessary number of replicas can be achieved through the proposed method, thereby providing a higher efficiency and the possibility of p...

Faller, R; De Pablo, J J; Faller, Roland; Yan, Qiliang; Pablo, Juan J. de

2002-01-01

77

Temperate flowering phenology.  

UK PubMed Central (United Kingdom)

Individuals, families, networks, and botanic gardens have made records of flowering times of a wide range of plant species over many years. These data can highlight year to year changes in seasonal events (phenology) and those datasets covering long periods draw interest for their perspective on plant responses to climate change. Temperate flowering phenology is complex, using environmental cues such as temperature and photoperiod to attune flowering to appropriate seasonal conditions. Here we give an overview of flowering phenological recording, outline different patterns of flowering, and look at the interpretation of datasets in relation to seasonal and climatic change.

Tooke F; Battey NH

2010-06-01

78

Flux Tempered Metadynamics  

Science.gov (United States)

There is considerable interest in developing methods for calculation of the free energy of fluids and materials from molecular simulations. Two prominent strategies, density-of-states sampling and "metadynamics," seek to achieve uniform sampling of states through judicious addition of biasing potentials. In the particular case of metadynamics, a biasing potential is identified on the basis of one or more order parameters, and the convergence of a simulation is assessed by determining how regularly a given value of the order parameter is visited. That approach, however, can be of limited utility when the free energy curve exhibits multiple minima of disparate magnitude. In this work, we report a modified version of the original metadynamics algorithm that is based on maximization of round-trips (or flux) along the order parameter. The effectiveness of the proposed "flux tempered" approach is demonstrated in the context of two simple model systems, namely a pair of Lennard-Jones particles and a butane molecule. In both cases the flux tempered metadynamics method is significantly faster and more accurate than existing versions of metadynamics. While the method introduced in this work is presented in reference to metadynamics approaches, the ideas proposed here can be applied to assess the convergence of free-energy calculations in general, provided the applied weights are differentiable with respect to the Cartesian coordinates of the system.

Singh, Sadanand; Chiu, Chi-Cheng; de Pablo, Juan J.

2011-11-01

79

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 fo...

Burgos Gil, José Ignacio

80

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

UK PubMed Central (United Kingdom)

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 ~10m height. There was little acclimation of photosynthetic capacity to eC and hence the CO2 -induced photosynthetic enhancement was large (~50%) in this treatment during summer. The warming treatment significantly increased rates of both carboxylation capacity (Vcmax ) 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. This article is protected by copyright. All rights reserved.

Crous KY; Quentin AG; Lin YS; Medlyn BE; Williams DG; Barton CV; Ellsworth DS

2013-07-01

 
 
 
 
81

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 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.

2009-01-01

82

Transfer parameter values in temperate forest ecosystems: a review  

Energy Technology Data Exchange (ETDEWEB)

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 (T{sub ag} in m{sup 2} kg{sup -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 T{sub ag} values was 10{sup -3} m{sup 2} kg{sup -1} (dry weight). Tree foliage 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 T{sub ag}, from 10{sup -3} to 10{sup 1} m{sup 2} kg{sup -1} (dry weight). For berries, typical values are around 0.01-0.1 m{sup 2} kg{sup -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 T{sub ag} value of 0.01 m{sup 2} kg{sup -1} (fresh weight) is common for {sup 137}Cs in the muscles of adult moose and terrestrial birds living in boreal forests, and 0.03 m{sup 2} kg{sup -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 T{sub ag} values for winter ranging from 0.02 to 0.8 m{sup 2} kg{sup -1} (fresh weight), and in summer from 0.04 to 0.4 m{sup 2} kg{sup -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 {sup 137}Cs has been found, with T{sub ag} values changing from 0.01 to 0.002 m{sup 2} kg{sup -1} (fresh weight) in the three years after the contaminating event, the rate being determined by the dynamics of {sup 137}Cs in aquatic ecosystems.

Calmon, Philippe [Department of Radioecology, Institute of Radioprotection and Nuclear Safety, CE Cadarache, BP 3, 13115 Saint Paul-les-Durance Cedex (France)], E-mail: philippe.calmon@irsn.fr; Thiry, Yves [Biosphere Impact Studies, Belgian Nuclear Research Center (SCK.CEN, Foundation of Public Utility), 2400 Mol (Belgium); Zibold, Gregor [Hochschule Ravensburg-Weingarten, University of Applied Sciences, 88250 Weingarten (Germany); Rantavaara, Aino [Research and Environmental Surveillance, Radiation and Nuclear Safety Authority (STUK), BP 14, FIN-00881 Helsinki (Finland); Fesenko, Sergei [International Atomic Energy Agency (IAEA), 1400 Vienna (Austria)

2009-09-15

83

process and apparates for continious tempering cacao butter containing massesor similar fat containing masses to be processed  

UK PubMed Central (United Kingdom)

Chocolate manufacturing process and assembly tempering zone sub-divided In the process and assembly to continually temper a mass of food containing cocoa butter or similar fatty masses, the food mass flows through a heating zone and a cooling circuit (9) in which a coolant passes in contra-flow to the mass through a mantle (5) within an evaporator (25). The food mass is tempered by direct evaporation. The process is regulated by varying the quantity of hot coolant in proportion to the temperature of the mass by a hot gas pipe (18) between the condenser (12) and expansion valve (14) in the coolant circuit (9). The novelty is that the tempering zone is sub-divided into a cooling zone (6) on the food mass inlet side and a crystallisation zone (7) on the outlet side. The hot coolant is only brought into contact with the hot gas pipe (18) via the tempering cooling zone (6). The hot coolant is led only in contra-flow past the hot gas pipe (18) to the tempering cooling zone (6).

Sollich Helmut

84

Temperate Forest Biome Field Trip  

Science.gov (United States)

This site focuses on the subject of the temperate forest biome. Specific topics include characteristics of the biome, tree types, seasonal changes, interdependence between plants and animals in the forest, and protecting the temperate forest. Designed as an electronic tour, it guides the user through different web sites and outlines teaching objectives, concepts covered, and new vocabulary. There is a teacher resources section with links for more information, and questions for students to answer along the way.

85

Time-temperature equivalence in Martensite tempering  

Energy Technology Data Exchange (ETDEWEB)

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

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

2008-01-01

86

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

Directory of Open Access Journals (Sweden)

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.

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

2010-01-01

87

Concussion in Winter Sports  

Science.gov (United States)

... Favorites Delicious Digg Google Bookmarks Concussion in Winter Sports Get prepared for concussions on and off the ... to enjoy, practice, and compete in various winter sports. There's no doubt that these sports are a ...

88

Diversity and abundance of photosynthetic sponges in temperate Western Australia.  

UK PubMed Central (United Kingdom)

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.

Lemloh ML; Fromont J; Brümmer F; Usher KM

2009-01-01

89

Winter-to-winter variations in indoor radon  

Energy Technology Data Exchange (ETDEWEB)

Indoor radon concentrations in northern Virginia and central Maryland show a strong dependence on weather. Winter tends to be associated with higher than average indoor radon, and summer with lower than average. However, compared to the winter of 1986-1987, the winter of 1987-1988 was warmer and drier. Consequently, winter-to-winter indoor radon decreased by about 25%. This winter-to-winter decrease is unexpectedly large, and simulates winter-to-summer variations that have been reported.

Mose, D.G.; Mushrush, G.W.; Kline, S.W. (George Mason Univ., Fairfax, VA (USA))

1989-01-01

90

Winter-to-winter variations in indoor radon  

International Nuclear Information System (INIS)

Indoor radon concentrations in northern Virginia and central Maryland show a strong dependence on weather. Winter tends to be associated with higher than average indoor radon, and summer with lower than average. However, compared to the winter of 1986-1987, the winter of 1987-1988 was warmer and drier. Consequently, winter-to-winter indoor radon decreased by about 25%. This winter-to-winter decrease is unexpectedly large, and simulates winter-to-summer variations that have been reported

1989-01-01

91

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

International Nuclear Information System (INIS)

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

1981-08-12

92

Tempered stable and tempered infinitely divisible GARCH models  

Digital Repository Infrastructure Vision for European Research (DRIVER)

In this paper, we introduce a new GARCH model with an infinitely divisible distributed innovation, referred to as the rapidly decreasing tempered stable (RDTS) GARCH model. This model allows the description of some stylized empirical facts observed for stock and index returns, such as volatility clu...

Kim, Young Shin; Rachev, Svetlozar T.; Bianchi, Michele Leonardo; Fabozzi, Frank J.

93

Tempered stable laws as random walk limits  

CERN Document Server

Stable laws can be tempered by modifying the L\\'evy measure to cool the probability of large jumps. Tempered stable laws retain their signature power law behavior, and infinite divisibility. This paper develops random walk models that converge to a tempered stable law under a triangular array scheme. Since tempered stable laws and processes are useful in statistical physics, these random walk models can provide a basic physical model for the underlying physical phenomena.

Chakrabarty, Arijit

2010-01-01

94

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 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 de 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 e (more) fectos 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 temperature 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 pl (more) ankton and fish from temperate regions (defined here as latitudes between 30-60º), especially from the Patagonia area, due to the special characteristics found in these sites. UVR affects (often negatively) almost all processes, from carbon fixation to behavior; and certainly all trophic levels in plankton, from virus to fish larvae. The most prominent UVR danger is probably the mutagenic action of UVB, which will affect a number of processes such as photosynthesis, growth and cell division, among many others. In metazoans, UVR may cause stress upon survival or show sublethal effects such as those in behavior and feeding. It is difficult to extract a general pattern, even in a group of organisms, as responses to UVR appear to be species-specific and strongly influenced by local conditions (e.g., UVR penetration, PAR/UVR ratios, and acclimation). While in many cases significant effects have been determined, a number of mechanisms are available to avoid and / or minimize the damage produced by UVR. However, this may not hold true for global t

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

2010-08-01

95

Chilling and heat requirements for flowering in temperate fruit trees.  

UK PubMed Central (United Kingdom)

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

Guo L; Dai J; Ranjitkar S; Yu H; Xu J; Luedeling E

2013-08-01

96

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

Digital Repository Infrastructure Vision for European Research (DRIVER)

We investigated the temperature dependency of photosynthetic rates for five Sphagnum species: Sphagnum palustre, S. fimbriatum in the Tadewara mire (south-western Japan in a warm-temperate zone) and S. papillosum, S. fuscum, S. fallax in the East Ochiishi mire (north-eastern Japan in a cool-temperat...

Akira Haraguchi; Nanae Yamada

97

Presence of Dalbulus maidis (Hemiptera: Cicadellidae) and of Spiroplasma kunkelii in the temperate region of Argentina.  

UK PubMed Central (United Kingdom)

"Corn stunt" is one of the main corn (Zea mays L.) diseases in the Americas and Dalbulus maidis (DeLong & Wolcott) is the key vector of the pathogen Spiroplasma kunkelii Whitcomb. In Argentina, the corn-producing area is in the temperate region, where vector and pathogen prevalence levels are unknown. In this study, the prevalence and distribution of D. maidis and S. kunkelii in the temperate region of Argentina and D. maidis overwintering ability in this region were determined. Surveys were conducted in 2005-2006 and 2006-2007 seasons to determine D. maidis and S. kunkelii presence, and in winter 2006 to determine the vector overwintering ability. The highest S. kunkelii prevalence and incidence levels were found in the transition area from the temperate to the subtropical region, related to the highest D. maidis prevalence and insects sampled per location. D. maidis adults were found in volunteer corn plants and spontaneous vegetation in autumn and winter months, which were inoculative for the pathogen S. kunkelii. This overwintering ability was related to detection of D. maidis insects in corn crops at early growth stages in the following growing season. This work emphasizes that corn stunt disease is present in the temperate region of Argentina, and this highlights the need to develop proper agronomic practices like monitoring insect vector populations and controlling voluntary plants. This study also indicates that further research is needed to understand the potential yield reduction caused by this pathogen on symptomless plants and population dynamics of the insect vector.

Carloni E; Carpane P; Paradell S; Laguna I; Pecci MP

2013-08-01

98

EFFECTIVENESS OF WINTER WHEAT VARIETIES OF WORLD SELECTION IN SOUTH URAL  

Directory of Open Access Journals (Sweden)

Full Text Available Varieties of winter wheat of world selection were studied in the conditions of South Ural. The conducted researches showed that in conditions of a steppe zone of South Ural possibly receiving more than 5,0 t of grain of winter wheat. For a steppe zone of South Ural four effective grades of winter wheat are defined: Kolos 47, Nika, KNIISH 756, Mironovskaya 64.

A. Glinushkin; O. Beloshapkina; S. Plygun; N. Nikolaev; T. Mishenina; G. Myasnyankina; V. Lukyantsev; S. Dushkin; E. Karamatova; A. Vasilyeva; N. Grigorieva; A. Solovykh; A. Rayov

2013-01-01

99

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.

1995-01-01

100

Cyclic voles and shrews and non-cyclic mice in a marginal grassland within European temperate forest.  

UK PubMed Central (United Kingdom)

Cyclic population dynamics of small mammals are not restricted to the boreal and arctic zones of Eurasia and North America, but long-term data series from lower latitudes are still less common. We demonstrated here the presence of periodic oscillations in small mammal populations in eastern Poland using 22-year (1986-2007) trapping data from marginal meadow and river valley grasslands located in the extensive temperate woodland of Bia?owie?a Primeval Forest. The two most common species inhabiting meadows and river valleys, root vole Microtus oeconomus and common shrew Sorex araneus, exhibited synchronous periodic changes, characterised by a 3-year time lag as indicated by an autocorrelation function. Moreover, the cycles of these two species were synchronous within both habitats. Population dynamics of the striped field mouse Apodemus agrarius was not cyclic. However, this species regularly reached maximum density 1 year before the synchronized peak of root voles and common shrews, which may suggest the existence of interspecific competition. Dynamics of all three species was dominated by direct density-dependent process, whereas delayed density dependent feedback was significant only in the root vole and common shrew. Climatic factors acting in winter and spring (affecting mainly survival and initial reproduction rates) were more important than those acting in summer and autumn and affected significantly only the common shrew. High temperatures in winter and spring had positive effects on autumn-to-autumn changes in abundance of this species, whereas deep snow in combination with high rainfall in spring negatively affected population increase rates in common shrew.

Zub K; J?drzejewska B; J?drzejewski W; Barto? KA

2012-07-01

 
 
 
 
101

Cyclic voles and shrews and non-cyclic mice in a marginal grassland within European temperate forest.  

Science.gov (United States)

Cyclic population dynamics of small mammals are not restricted to the boreal and arctic zones of Eurasia and North America, but long-term data series from lower latitudes are still less common. We demonstrated here the presence of periodic oscillations in small mammal populations in eastern Poland using 22-year (1986-2007) trapping data from marginal meadow and river valley grasslands located in the extensive temperate woodland of Bia?owie?a Primeval Forest. The two most common species inhabiting meadows and river valleys, root vole Microtus oeconomus and common shrew Sorex araneus, exhibited synchronous periodic changes, characterised by a 3-year time lag as indicated by an autocorrelation function. Moreover, the cycles of these two species were synchronous within both habitats. Population dynamics of the striped field mouse Apodemus agrarius was not cyclic. However, this species regularly reached maximum density 1 year before the synchronized peak of root voles and common shrews, which may suggest the existence of interspecific competition. Dynamics of all three species was dominated by direct density-dependent process, whereas delayed density dependent feedback was significant only in the root vole and common shrew. Climatic factors acting in winter and spring (affecting mainly survival and initial reproduction rates) were more important than those acting in summer and autumn and affected significantly only the common shrew. High temperatures in winter and spring had positive effects on autumn-to-autumn changes in abundance of this species, whereas deep snow in combination with high rainfall in spring negatively affected population increase rates in common shrew. PMID:22707756

Zub, K; J?drzejewska, B; J?drzejewski, W; Barto?, K A

2012-02-14

102

Photosynthetic Acclimation to Cold as a Potential Physiological Marker of Winter Barley Freezing Tolerance Assessed under Variable Winter Environment  

UK PubMed Central (United Kingdom)

Winter-hardiness is a complex trait limiting cultivation of winter barley (Hordeum vulgare ssp. vulgare) with respect to the regions of temperate climate. In the present studies, we verified whether inexpensive and fast physiological markers characterizing photosynthetic acclimation to cold may provide robust characteristics of winter barley genotypes for improved frost resistance. Freezing tolerance of 28 winter barley varieties and advanced breeding lines were tested for three winters in field-laboratory experiment and under fully controlled conditions. To increase the environmental variability of freezing tolerance, a part of the plants were also de-acclimated under semi-controlled conditions and re-acclimated in laboratory before freezing tests. After controlled cold acclimation, apparent quantum yield of photosystem II (Fv/Fm) as well as photochemical (qP) and non-photochemical (NPQ) coefficients of chlorophyll fluorescence quenching were studied. Field-laboratory method assessment of freezing tolerance gives distinct and even opposite results in subsequent years. Also de-acclimation interacted with growth conditions in the field, giving different rankings of genotypes each year. The results obtained suggest that high level of freezing tolerance measured in laboratory, which is connected with photosynthetic acclimation to cold may be not sufficient for the expression of field resistance, especially when winter conditions are not favourable for cold acclimation.

Rapacz M; Tyrka M; Kaczmarek W; Gut M; Wolanin B; Mikulski W

2008-02-01

103

Summer dormancy in perennial temperate grasses.  

UK PubMed Central (United Kingdom)

BACKGROUND AND AIMS: Dormancy has been extensively studied in plants which experience severe winter conditions but much less so in perennial herbaceous plants that must survive summer drought. This paper reviews the current knowledge on summer dormancy in both native and cultivated perennial temperate grasses originating from the Mediterranean Basin, and presents a unified terminology to describe this trait. SCOPE: Under severe drought, it is difficult to separate the responses by which plants avoid and tolerate dehydration from those associated with the expression of summer dormancy. Consequently, this type of endogenous (endo-) dormancy can be tested only in plants that are not subjected to moisture deficit. Summer dormancy can be defined by four criteria, one of which is considered optional: (1) reduction or cessation of leaf production and expansion; (2) senescence of mature foliage; (3) dehydration of surviving organs; and (4, optional) formation of resting organs. The proposed terminology recognizes two levels of summer dormancy: (a) complete dormancy, when cessation of growth is associated with full senescence of foliage and induced dehydration of leaf bases; and (b) incomplete dormancy, when leaf growth is partially inhibited and is associated with moderate levels of foliage senescence. Summer dormancy is expressed under increasing photoperiod and temperature. It is under hormonal control and usually associated with flowering and a reduction in metabolic activity in meristematic tissues. Dehydration tolerance and dormancy are independent phenomena and differ from the adaptations of resurrection plants. CONCLUSIONS: Summer dormancy has been correlated with superior survival after severe and repeated summer drought in a large range of perennial grasses. In the face of increasing aridity, this trait could be used in the development of cultivars that are able to meet agronomic and environmental goals. It is therefore important to have a better understanding of the genetic and environmental control of summer dormancy.

Volaire F; Norton M

2006-11-01

104

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; Milton Sérgio Fernandes de Lima

2012-01-01

105

Laser beam welding tempered 300M ultrahigh mechanical strength steel  

Scientific Electronic Library Online (English)

Full Text Available 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 (more) 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.

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

2012-03-01

106

Rates of nocturnal transpiration in two evergreen temperate woodland species with differing water-use strategies.  

UK PubMed Central (United Kingdom)

Nocturnal fluxes may be a significant factor in the annual water budget of forested ecosystems. Here, we assessed sap flow in two co-occurring evergreen species (Eucalyptus parramattensis and Angophora bakeri) in a temperate woodland for 2 years in order to quantify the magnitude of seasonal nocturnal sap flow (E(n)) under different environmental conditions. The two species showed different diurnal water relations, demonstrated by different diurnal curves of stomatal conductance, sap flow and leaf water potential. The relative influence of several microclimatic variables, including wind speed (U), vapour pressure deficit (D), the product of U and D (UD) and soil moisture content, were quantified. D exerted the strongest influence on E(n) (r² = 0.59-0.86), soil moisture content influenced E(n) when D was constant, but U and UD did not generally influence E(n). In both species, cuticular conductance (G(c)) was a small proportion of total leaf conductance (G(s)) and was not a major pathway for E(n). We found that E(n) was primarily a function of transpiration from the canopy rather than refilling of stem storage, with canopy transpiration accounting for 50-70% of nocturnal flows. Mean E(n) was 6-8% of the 24-h flux across seasons (spring, summer and winter), but was up to 19% of the 24-h flux on some days in both species. Despite different daytime strategies in water use of the two species, both species demonstrated low night-time water loss, suggesting similar controls on water loss at night. In order to account for the impact of E(n) on pre-dawn leaf water potential arising from the influence of disequilibria between root zone and leaf water potential, we also developed a simple model to more accurately predict soil water potential (?(s)).

Zeppel M; Tissue D; Taylor D; Macinnis-Ng C; Eamus D

2010-08-01

107

Nutrition for winter sports.  

UK PubMed Central (United Kingdom)

Winter sports are played in cold conditions on ice or snow and often at moderate to high altitude. The most important nutritional challenges for winter sport athletes exposed to environmental extremes include increased energy expenditure, accelerated muscle and liver glycogen utilization, exacerbated fluid loss, and increased iron turnover. Winter sports, however, vary greatly regarding their nutritional requirements due to variable physiological and physique characteristics, energy and substrate demands, and environmental training and competition conditions. What most winter sport athletes have in common is a relatively lean physique and high-intensity training periods, thus they require greater energy and nutrient intakes, along with adequate food and fluid before, during, and after training. Event fuelling is most challenging for cross-country skiers competing in long events, ski jumpers aiming to reduce their body weight, and those winter sport athletes incurring repeated qualification rounds and heats. These athletes need to ensure carbohydrate availability throughout competition. Finally, winter sport athletes may benefit from dietary and sport supplements; however, attention should be paid to safety and efficacy if supplementation is considered.

Meyer NL; Manore MM; Helle C

2011-01-01

108

Nutrition for winter sports.  

Science.gov (United States)

Winter sports are played in cold conditions on ice or snow and often at moderate to high altitude. The most important nutritional challenges for winter sport athletes exposed to environmental extremes include increased energy expenditure, accelerated muscle and liver glycogen utilization, exacerbated fluid loss, and increased iron turnover. Winter sports, however, vary greatly regarding their nutritional requirements due to variable physiological and physique characteristics, energy and substrate demands, and environmental training and competition conditions. What most winter sport athletes have in common is a relatively lean physique and high-intensity training periods, thus they require greater energy and nutrient intakes, along with adequate food and fluid before, during, and after training. Event fuelling is most challenging for cross-country skiers competing in long events, ski jumpers aiming to reduce their body weight, and those winter sport athletes incurring repeated qualification rounds and heats. These athletes need to ensure carbohydrate availability throughout competition. Finally, winter sport athletes may benefit from dietary and sport supplements; however, attention should be paid to safety and efficacy if supplementation is considered. PMID:22150424

Meyer, Nanna L; Manore, Melinda M; Helle, Christine

2011-06-21

109

Global warming reduces plant reproductive output for temperate multi-inflorescence species on the Tibetan plateau.  

UK PubMed Central (United Kingdom)

• Temperature is projected to increase more during the winter than during the summer in cold regions. The effects of winter warming on reproductive effort have not been examined for temperate plant species. • Here, we report the results of experimentally induced seasonal winter warming (0.4 and 2.4°C increases in growing and nongrowing seasons, respectively, using warmed and ambient open-top chambers in a Tibetan Plateau alpine meadow) for nine indeterminate-growing species producing multiple (single-flowered or multi-flowered) inflorescences and three determinate-growing species producing single inflorescences after a 3-yr period of warming. • Warming reduced significantly flower number and seed production per plant for all nine multi-inflorescence species, but not for the three single-inflorescence species. Warming had an insignificant effect on the fruit to flower number ratio, seed size and seed number per fruit among species. The reduction in seed production was largely attributable to the decline in flower number per plant. The flowering onset time was unaffected for nine of the 12 species. Therefore, the decline in flower production and seed production in response to winter warming probably reflects a physiological response (e.g. metabolic changes associated with flower production). • Collectively, the data indicate that global warming may reduce flower and seed production for temperate herbaceous species and will probably have a differential effect on single- vs multi-inflorescence species.

Liu Y; Mu J; Niklas KJ; Li G; Sun S

2012-07-01

110

Physiological processes during winter dormancy and their ecological significance  

Energy Technology Data Exchange (ETDEWEB)

Lengthy and severe winters require that trees in the forests of boreal and mountain zones undergo winter dormancy. Physiologically, a high resistance to subfreezing temperatures and concomitant dehydration are necessary. To accomplish this dormancy, both physiological and structural changes are needed at the cellular level that require induction by endogenous and photoperiodic control early in autumn. Endogenous rhythmicity promotes cold hardening in early autumn and the persistence of hardiness throughout the winter. Numerous physiological functions are maintained at a reduced level, or become completely inhibited during true winter dormancy. Winter hardiness also includes the capability to minimize water loss effectively when water uptake is severely impeded or impossible. Anatomical features such as tracheids act to minimize xylem embolism during frequent freeze-thaw cycles, and {open_quotes}crown{close_quotes} tissues enable buds to stay in a dehydrated and, thus, more resistant state during winter. Both these structural features are adaptations that contribute to the dominance of conifers in cold climates. Interestingly, deciduous tree species rather than evergreen conifers dominate in the most severe winter climates, although it is not clear whether limitations during winter, during the summer growth period, or during both are most limiting to conifer tree ecology. Additional work that evaluates the importance of winter and summer growth restriction, and their interaction, is needed before a comprehensive understanding of conifer tree ecophysiology will be possible.

Havranek, W.M.; Tranquillini, W.

1995-07-01

111

System and method for providing tempered fluid  

UK PubMed Central (United Kingdom)

The present invention is directed to methods and apparatus for tempering the temperature of a liquid in a fluid conducting system. More particularly, the invention relates to tempering the temperature of water supplied to a fixture from a water heater in a fluid conducting system.

ROBERT EVELEIGH; GARY COOK

112

SYSTEM AND METHOD FOR PROVIDING TEMPERED FLUID  

UK PubMed Central (United Kingdom)

The present invention is directed to methods and apparatus for tempering the temperature of a liquid in a fluid conducting system. More particularly, the invention relates to tempering the temperature of water supplied to a fixture from a water heater in a fluid conducting system.

EVELEIGH ROBERT; COOK GARY

113

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

114

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; Elva Escobar; Luis A. Oseguera

2008-01-01

115

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 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 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 circu (more) lación 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 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 (more) 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.

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

2008-08-01

116

Stable isotopic insight into pelagic carbon cycling in Loch Lomond : a large, temperate latitude lake.  

UK PubMed Central (United Kingdom)

Lakes play an important role in biosphere carbon dynamics. Though proportionally they constitute a small surface feature on the planet, in many cases lakes are subject to significant subsidies of organic material from their catchments. This input of allochthonous organic material, in addition to autochthonous organic material, has shown that lakes, particularly in temperate and boreal zones, can be heterotrophic systems and as such are net producers of CO2. Thus, understanding the magnitude of fluxes of carbon through these limnetic systems is important if their contribution to ecosystem / global carbon dynamics is to be elucidated. In this research two separate field campaigns were undertaken with the goal of understanding if, and exactly how significant secondary (bacterial) production utilising allochthonous carbon is to overall pelagic production in Loch Lomond, Scotland. Stable isotopic composition of dissolved inorganic carbon (DIC), dissolved oxygen (DO), dissolved organic carbon (DOC) and total dissolved nitrogen (TDN), along with their respective concentrations, were measured in a temporal and spatial survey. Range in [DIC] and ?13CDIC was consistent with that predicted by the shifting balance between autotrophic and heterotrophic pathways. [DIC] peaked in the summer / autumn (0.27 ± 0.09 and 0.17 ± 0.05 mM, south and north basins respectively), reflecting a period when bacterial processing of allochthonous material is high, and thus so is CO2 production. This effect was more pronounced in the mesotrophic south basin of the lake, compared to the oligotrophic north. Surface waters in the south, middle and north basins were generally saturated in CO2 beyond atmospheric equilibrium and thus sources of CO2 to the atmosphere. ?13CDIC and ?18ODO exhibited seasonal and spatial variability, probably also a result of changing metabolic balance and inflow characteristics. Spring / summer peaks in ?13CDIC (-5.1‰ epilimnion maximum) are indicative of photosynthetic incorporation, and vice versa in the autumn / winter (-13‰ hypolimnion minimum) points towards respiratory dominance. ?18ODO is enriched during respiratory utilisation and peaks in the autumn / winter months. Depletion in ?13CDIC coupled to concurrent enrichment in ?18ODO observed with increasing depth (particularly during lake stratification) is assumed to again be a result of a shift in metabolic process dominance from autotrophic to heterotrophic (Myrbo and Shapley 2006). Spatial variability was consistent with the varying trophic states between basins, e.g., most enriched ?13CDIC was recorded in the more productive south basin compared to the middle or north. Dissolved organic carbon concentration also changed with position in the lake. Highest concentrations in the south basin were linked to a shallow gradient catchment, draining base rich soils and agricultural land, compared to the steep sloped, base-poor catchment in the north. The greater quantities of dissolved organic carbon in the south suggested that if bacterial processing of allochthonous material was significant it would likely be most prevalent in the south. During the spatial survey consistent and significant heterogeneity in DIC, DO and DOC was recorded. Although the same degree of variability may not be associated with other, more mophometrically / hydrologically simple lakes, this work has shown consideration of this possibility is advisable. The second field campaign used direct measurements of algal and bacterial productivity, using labelled stable isotope incorporation methods, to elucidate the balance between autotrophic and heterotrophic processes. Primary production (PP) followed a predictable seasonal pattern, peaking in the spring and remaining relatively high until autumn. During this period primary production generally exceeded bacterial production (BP) per litre. During the winter this pattern was reversed. Using integrated estimates of both PP and BP this work showed that BP exceeded PP in the pelagic zone for the majority of the year, and over much of the lake’s e

Bass AM

117

Water relations of climbing ivy in a temperate forest.  

UK PubMed Central (United Kingdom)

Ivy (Hedera helix) is the most important liana in temperate European forests. We studied water relations of adult ivy in a natural, 35 m tall mixed deciduous forest in Switzerland using a construction crane to access the canopy. Predawn leaf water potential at the top of climbing ivy ranged from -0.4 to -0.6 MPa, daily minima ranged from -1.3 to -1.7 MPa. Leaf water potentials as well as relative sap flow were held surprisingly constant throughout different weather conditions, suggesting a tendency to isohydric behaviour. Maximum stomatal conductance was 200 mmol m?² s?¹. The use of a potometer experiment allowed us to measure absolute transpiration rates integrated over a whole plant of 0.23 mmol m?² s?¹. Nightly sap flow of ivy during warm, dry nights accounted for up to 20% of the seasonal maximum. Maximum sap flow rates were reached at ca. 0.5 kPa vpd. On the other hand, the host trees showed a less conservative stomatal regulation, maximum sap flow rates were reached at vpd values of ca. 1 kPa. Sap flow rates of ivy decreased by ca. 20% in spring after bud break of trees, suggesting that ivy profits strongly from warm sunny days in early spring before budbreak of the host trees and from mild winter days. This species may benefit from rising winter temperatures in Europe and thus become a stronger competitor against its host trees.

Leuzinger S; Hartmann A; Körner C

2011-06-01

118

Water relations of climbing ivy in a temperate forest.  

Science.gov (United States)

Ivy (Hedera helix) is the most important liana in temperate European forests. We studied water relations of adult ivy in a natural, 35 m tall mixed deciduous forest in Switzerland using a construction crane to access the canopy. Predawn leaf water potential at the top of climbing ivy ranged from -0.4 to -0.6 MPa, daily minima ranged from -1.3 to -1.7 MPa. Leaf water potentials as well as relative sap flow were held surprisingly constant throughout different weather conditions, suggesting a tendency to isohydric behaviour. Maximum stomatal conductance was 200 mmol m?² s?¹. The use of a potometer experiment allowed us to measure absolute transpiration rates integrated over a whole plant of 0.23 mmol m?² s?¹. Nightly sap flow of ivy during warm, dry nights accounted for up to 20% of the seasonal maximum. Maximum sap flow rates were reached at ca. 0.5 kPa vpd. On the other hand, the host trees showed a less conservative stomatal regulation, maximum sap flow rates were reached at vpd values of ca. 1 kPa. Sap flow rates of ivy decreased by ca. 20% in spring after bud break of trees, suggesting that ivy profits strongly from warm sunny days in early spring before budbreak of the host trees and from mild winter days. This species may benefit from rising winter temperatures in Europe and thus become a stronger competitor against its host trees. PMID:21293876

Leuzinger, S; Hartmann, A; Körner, C

2011-02-04

119

Winter camelina in the Northern U.S. and the potential of its use in double-cropping  

Science.gov (United States)

Camelina (Camelina sativa L.) seed oil can serve as feedstock for advanced biofuels and may be produced more cheaply than traditional oilseeds such as soybean [Glycine max (L.) Merr.]. In cool, temperate climates such as that of the Corn Belt Region of the U.S., camelina can be grown as a winter or ...

120

Cropping systems control winter annual grass weeds in winter wheat.  

UK PubMed Central (United Kingdom)

Downy brome (Bromus tectorum L.), jointed goatgrass (Aegilops cylindrica Host), and volunteer cereal rye (Secale cereale L.) are winter annual grass weeds that are increasingly troublesome in the winter wheat (Triticum aestivum L. emend. Thell.)-fallow rotation areas of the western USA. Six dryland cropping systems--continuous no-till winter wheat, winter wheat-fallow with fall tillage, winter wheat-fallow with fall applied herbicide, winter wheat-fallow-fallow, winter wheat-sunflower-fallow, and winter wheat-proso millet-fallow--were compared for their effect on winter annual grass densities in winter wheat. Winter annual grass densities averaged 145, 4.4, and 0.4 plants/sq yard for the 1-, 2-, and 3-yr systems, respectively. Eradication of the winter annual grasses was not achieved with any of the systems. Dockage and foreign material levels in wheat grain were lower in 3-yr than in 2-yr cropping systems. Jointed goatgrass was the most persistent annual grass investigated.

Lyon DJ; Baltensperger DD

1995-12-01

 
 
 
 
121

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 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 principale (more) s) 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. Classification (cluster analysis) and ordination (principal component analysis) techniques were used to segregate and examine the communities. Biodiversity indicators including (more) 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

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

2011-01-01

122

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, permanece

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

2011-01-01

123

Tempering stresses in feldspathic porcelain.  

UK PubMed Central (United Kingdom)

The objective of this study was to develop an analytical model to calculate transient and residual (tempering) stresses in dental porcelain plates subjected to cooling rates used by commercial laboratories. The model incorporates linear viscoelasticity and structural relaxation effects. The viscosities of three experimental body porcelains and three experimental opaque porcelains as a function of temperature were calculated from creep rates measured in a bending beam viscometer. Measurements were made under thermal equilibrium conditions for temperatures ranging from 550 degrees C to 625 degrees C. Thermal expansion data measured in a differential dilatometer at slow heating rates were supplied by the manufacturer. Temperature distribution in the plates as a function of convective heat transfer coefficient, initial plate temperature, and plate thickness was calculated by use of standard numerical techniques. Calculations of transient and residual stress were performed for one body porcelain, for two plate thicknesses, and for three variable cooling rates. Calculated surface residual stresses were strongly dependent on plate thickness, cooling rate, and initial soak temperature. For the cases studied, the maximum residual surface compressive stress was 26.4 MPa.

Dehoff PH; Anusavice KJ

1989-02-01

124

Editorial - The winter Atomiades  

CERN Document Server

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

125

Winter cardiovascular diseases phenomenon.  

UK PubMed Central (United Kingdom)

THIS PAPER REVIEW SEASONAL PATTERNS ACROSS TWELVE CARDIOVASCULAR DISEASES: Deep venous thrombosis, pulmonary embolism, aortic dissection and rupture, stroke, intracerebral hemorrhage, hypertension, heart failure, angina pectoris, myocardial infarction, sudden cardiac death, venricular arrythmia and atrial fibrillation, and discuss a possible cause of the occurrence of these diseases. There is a clear seasonal trend of cardiovascular diseases, with the highest incidence occurring during the colder winter months, which have been described in many countries. This phenomenon likely contributes to the numbers of deaths occurring in winter. The implications of this finding are important for testing the relative importance of the proposed mechanisms. Understanding the influence of season and other factors is essential when seeking to implement effective public health measures.

Fares A

2013-04-01

126

Winter in Bavaria  

Directory of Open Access Journals (Sweden)

Full Text Available "A Winter In Bavaria" was written on location in Regensburg, Germany, and is the first-hand account of a cataclysm, already predicted by Nostradamus, which changed the direction of Bavarian culture forever. Anything vaguely resembling an allusion to any real person or institution is entirely coincidental, has no foundation in fact and is clearly the product of a mind estranged - except that Bavarian beer is, by and large, still to be highly recommended.

Anthony Stephens

2004-01-01

127

Winter weather forecasts  

Science.gov (United States)

Once again, forecasters from both the National Oceanic and Atmospheric Administration's (NOAA) National Weather Service and the Scripps Institution of Oceanography's (SIO) Climate Research Group have independently formulated extended winter weather forecasts for the continental United States for December 1984 through February 1985. This year both groups have devised generally agreeing forecasts: Colder than normal weather in the western part of the nation, generally milder temperatures in the east (Figure 1), and on the whole, more than average precipitation over the entire nation (Figure 2). Both teams of forecasters use, in part, data on ocean surface temperatures collected in the North Pacific and North Atlantic as indications of likely weather patterns over the continents.First the National Weather Service's forecast: According to Donald L. Gilman, chief of the Predictions Branch at NOAA's National Weather Service, the greatest chance, or 60%, for colder than normal weather this winter is found in Utah and portions of Idaho, Wyoming, Colorado, New Mexico, Arizona, and Nevada. Surrounding this region, extending eastward from the Cascade and Siena Nevada mountains across the Great Basin and into the Rocky Mountains and the High Plains of Colorado, New Mexico, and west Texas, is an area that NOAA forecasters have given a 55% chance of colder than normal winter temperatures.

Robb, David W.

128

Consistent shifts in spring vegetation green-up date across temperate biomes in China, 1982-2006.  

Science.gov (United States)

Understanding spring phenology changes in response to the rapid climate change at biome-level is crucial for projecting regional ecosystem carbon exchange and climate-biosphere interactions. In this study, we assessed the long-term changes and responses to changing climate of the spring phenology in six temperate biomes of China by analyzing the global inventory monitoring and modeling studies (GIMMS) NOAA/AVHRR Normalized Difference Vegetation Index (NDVI) and concurrent mean temperature and precipitation data for 1982-2006. Results show that the spring phenology trends in the six temperate biomes are not continuous throughout the 25 year period. The spring phenology in most areas of the six biomes showed obvious advancing trends (ranging from -0.09 to -0.65 day/yr) during the 1980s and early 1990s, but has subsequently suffered consistently delaying trends (ranging from 0.22 to 1.22 day/yr). Changes in spring (February-April) temperature are the dominating factor governing the pattern of spring vegetation phenology in the temperate biomes of China. The recently delayed spring phenology in these temperate biomes has been mainly triggered by the stalling or reversal of the warming trend in spring temperatures. Results in this study also reveal that precipitation during November-January can explain 16.1% (P < 0.05), 20.9% (P < 0.05) and 14.2% (P < 0.05) of the variations in temperate deciduous forest (TDF), temperate steppe (TS), temperate desert (TD) respectively, highlighting the important role of winter precipitation in regulating changes in the spring vegetation phenology of water-limited biomes. PMID:23504843

Wu, Xiuchen; Liu, Hongyan

2012-12-21

129

Consistent shifts in spring vegetation green-up date across temperate biomes in China, 1982-2006.  

UK PubMed Central (United Kingdom)

Understanding spring phenology changes in response to the rapid climate change at biome-level is crucial for projecting regional ecosystem carbon exchange and climate-biosphere interactions. In this study, we assessed the long-term changes and responses to changing climate of the spring phenology in six temperate biomes of China by analyzing the global inventory monitoring and modeling studies (GIMMS) NOAA/AVHRR Normalized Difference Vegetation Index (NDVI) and concurrent mean temperature and precipitation data for 1982-2006. Results show that the spring phenology trends in the six temperate biomes are not continuous throughout the 25 year period. The spring phenology in most areas of the six biomes showed obvious advancing trends (ranging from -0.09 to -0.65 day/yr) during the 1980s and early 1990s, but has subsequently suffered consistently delaying trends (ranging from 0.22 to 1.22 day/yr). Changes in spring (February-April) temperature are the dominating factor governing the pattern of spring vegetation phenology in the temperate biomes of China. The recently delayed spring phenology in these temperate biomes has been mainly triggered by the stalling or reversal of the warming trend in spring temperatures. Results in this study also reveal that precipitation during November-January can explain 16.1% (P < 0.05), 20.9% (P < 0.05) and 14.2% (P < 0.05) of the variations in temperate deciduous forest (TDF), temperate steppe (TS), temperate desert (TD) respectively, highlighting the important role of winter precipitation in regulating changes in the spring vegetation phenology of water-limited biomes.

Wu X; Liu H

2013-03-01

130

Seasonality of flowering and fruiting in temperate forest trees  

Energy Technology Data Exchange (ETDEWEB)

A preliminary assessment of the coordination of foliar and reproductive phenology in broad leaf deciduous trees of the northern temperate zone was made using long-term phenological records. It was found that foliar and reproductive phenology was only weakly coupled within a growing season, in trees that fruit in early summer. For tree species with fruit maturing in late summer and fall, timing of leaf emergence and flowering had a limited effect on the timing of fruit maturation. Timing of foliar senescence and fruit maturation in fall fruiting trees only, was correlated to fall climate. It was tentatively concluded that global climate change may disrupt these patterns, but the effect will depend on the poorly studied balance of thermal versus photo periodic cues for phenological events.

Lechowicz, Martin J.

1995-02-01

131

Hydrology of wetlands in temperate and cold regions  

Energy Technology Data Exchange (ETDEWEB)

This publication contains the proceedings of the International Symposium on the Hydrology of Wetlands in Temperate and Cold Regions, held in Joensuu, Finland, on 6-8 June, 1988. Hydrology of particular regions and land areas has been one of the main themes during the International Hydrological Program III by UNESCO. A primary task of the International Hydrological Decade was to establish physical laws common to all geographical and climate regions. Programmes for example on snow, ice, wetlands, urban areas, etc., evolved and the need was felt to embark more on the hydrology on such special zones. This direction was followed during IHP-II by organizing seminars and workshops and by developing 'comparative hydrology'. During IHP-III, under the theme 'hydrology of particular regions', the characteristics of different hydrological regimes, swamps and.

Rantajaervi, L.

1988-01-01

132

Hydrology of wetlands in temperate and cold regions. Volume 1  

Energy Technology Data Exchange (ETDEWEB)

This publication contains the proceedings of the International Symposium on the Hydrology of Wetlands in Temperate and Cold Regions, held in Joensuu, Finland, on 6-8 June, 1988. Hydrology of particular regions and land areas has been one of the main themes during the International Hydrological Program III by UNESCO. A primary task of the International Hydrological Decade was to establish physical laws common to all geographical and climate regions. Programmes for example on snow, ice, wetlands, urban areas, etc., evolved and the need was felt to embark more on the hydrology on such special zones. This direction was followed during IHP-II by organizing seminars and workshops and by developing `comparative hydrology`. During IHP-III, under the theme `hydrology of particular regions`, the characteristics of different hydrological regimes, swamps and marshes included was studied.

Rantajaervi, L.

1988-12-31

133

Hydrology of wetlands in temperate and cold regions. Volume 2  

Energy Technology Data Exchange (ETDEWEB)

This publication contains the proceedings of the International Symposium on the Hydrology of Wetlands in Temperate and Cold Regions, held in Joensuu, Finland, on 6-8 June, 1988. Hydrology of particular regions and land areas has been one of the main themes during the International Hydrological Program III by UNESCO. A primary task of the International Hydrological Decade was to establish physical laws common to all geographical and climate regions. Programmes for example on snow, ice, wetlands, urban areas, etc., evolved and the need was felt to embark more on the hydrology on such special zones. This direction was followed during IHP-II by organizing seminars and workshops and by developing `comparative hydrology`. During IHP-III, under the theme `hydrology of particular regions`, the characteristics of different hydrological regimes, swamps and.

Rantajaervi, L.

1988-12-31

134

Hydrology of wetlands in temperate and cold regions  

Energy Technology Data Exchange (ETDEWEB)

This publication contains the proceedings of the International Symposium on the Hydrology of Wetlands in Temperate and Cold Regions, held in Joensuu, Finland, on 6-8 June, 1988. Hydrology of particular regions and land areas has been one of the main themes during the International Hydrological Program III by UNESCO. A primary task of the International Hydrological Decade was to establish physical laws common to all geographical and climate regions. Programmes for example on snow, ice, wetlands, urban areas, etc., evolved and the need was felt to embark more on the hydrology on such special zones. This direction was followed during IHP-II by organizing seminars and workshops and by developing 'comparative hydrology'. During IHP-III, under the theme 'hydrology of particular regions', the characteristics of different hydrological regimes, swamps and marshes included was studied.

Rantajaervi, L.

1988-01-01

135

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

Directory of Open Access Journals (Sweden)

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

Miao Miao; Yang Zhaoqing; Patch Harland; Huang Yaming; Escalante Ananias A; Cui Liwang

2012-01-01

136

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.

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

2013-01-01

137

Autodeformation of Carburized Steel during Tempering  

Directory of Open Access Journals (Sweden)

Full Text Available The article analyses the results of autodeformation registered during tempering of carburized steel. Test pieces for the tests were carburized till the different depth in order to examine influence of depth of carburization on the deformation of steel during heat treatment operation. Carburization was performed on the one surface of test pieces seeking to analyze extent of acted normal stresses to autodeformation of steel. Different bending loads were applied for analyzed steel from 5 MPa to 100 MPa. Deflection of test pieces was analyzed. The obtained results proved that size and direction of deflection were affected by depth of carburization. Particular results of stretched and compressed surface examination showed different behavior of test pieces during tempering process. Test pieces, which undergo deformation at the beginning of martensitic transformation, after unloading bend further. When tempered test pieces with assimetrically carburized layer bend during hardening, its direction and extent of autodeformation depend on depth of carburization and tempering temperature. Kinetics of autodeformation (during tempering) is affected by difference of volume changes in the carburized part and in the unaffected low carbon part of specimen, and similarly by decomposition of retained austenite in the carburized part.DOI: http://dx.doi.org/10.5755/j01.ms.19.1.3820

Regita BENDIKIEN?; Rasa VITKEVI?IEN?

2013-01-01

138

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

UK PubMed Central (United Kingdom)

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 < 0.01) during 1982-1998, and delayed at a rate of 2.13 day yr(-1) (P = 0.07) during 1998-2005, against a warming trend throughout the entire study period of 1982-2005. Spring air temperature strongly regulated the SGS of both deciduous broad-leaf and coniferous forests, whereas the winter snow had a greater impact on the SGS of grassland and shrubs. Snow depth variation combined with air temperature contributed to the variability in the SGS of grassland and shrubs, as snow acted as an insulator and modulated the underground thermal conditions. In addition, differences were seen between the impacts of winter snow depth and spring snow depth on the SGS; as snow depths increased, the effect associated went from delaying SGS to advancing SGS. The observed thresholds for these effects were snow depths of 6.8 cm (winter) and 4.0 cm (spring). The results of this study suggest that the response of the vegetation's SGS to seasonal snow change may be attributed to the coupling effects of air temperature and snow depth associated with the underground thermal conditions.

Yu Z; Liu S; Wang J; Sun P; Liu W; Hartley DS

2013-07-01

139

Why does Viola hondoensis (Violaceae) shed its winter leaves in spring?  

UK PubMed Central (United Kingdom)

• Premise of the study: Viola hondoensis is a perennial herb that inhabits the understory of temperate, deciduous forests. It is an evergreen plant with a leaf life span that is shorter than a year. Its summer leaves are produced in spring and shed in autumn; winter leaves are produced in autumn and shed in spring. Here we asked why the plant sheds its winter leaves in spring, though climate conditions improve from spring to summer. We proposed four hypotheses for the cause of shedding: (1) changes in seasonal environment such as day length or air temperature, (2) shading by canopy deciduous trees, (3) self-shading by taller summer leaves, and (4) competition for nutrients between summer and winter leaves. • Methods: To test these hypotheses, we manipulated the environment of winter leaves: (1) plants were transplanted to the open site where there was no shading by canopy trees. (2) Petioles of summer leaves were anchored to the soil surface to avoid shading of winter leaves. (3) Sink organs were removed to eliminate nutrient competition. • Key results: Longevity of winter leaves was extended when shading by summer leaves was eliminated and when sink organs were removed, but not when plants were transplanted to the open site. • Conclusion: We conclude that the relative difference in light availability between summer and winter leaves is a critical factor for regulation of leaf shedding, consistent with the theory of maximization of the whole-plant photosynthesis.

Hikosaka K; Kawauchi Y; Kurosawa T

2010-12-01

140

Consequences of nuclear winter  

Energy Technology Data Exchange (ETDEWEB)

It is to be expected that the predictable consequences of a nuclear war are more terrible than any of the indirect effects that have been discussed. Detailed calculations on the consequences of massive release of smoke seem to bear out this general expectation. This contrast may become ever more obvious if one takes into account the consequences of defense against a nuclear attack. One cannot expect that such defense will be 100% effective. A reduction of the direct casualties by a factor of 2 will almost certainly result in a substantial reduction in the amount of smoke emitted. In case of no defense, the direct effects of nuclear winter are hard to predict. In the case of defense, the climate changes may well be minor. If one assumes that there will be residual effects on the weather, this is apt to be more important in influencing precipitation rather than the surface temperature. Indeed, the main effect of smoke is to produce a temperature inversion and thereby suppress the convective rainfall. This is particularly true in many regions that produce crops in the norther hemisphere. It seems now well established that the most dangerous potential consequence of any smoke-induced climatic change will be reduction of crops. Fortunately, this danger can be greatly reduced by food storage. Such food storage could greatly reduce domestic shortages in the United States and could also be important in alleviating suffering abroad. The efforts spent on considering the consequence of nuclear winter are not wasted.

Teller, E.

1987-01-01

 
 
 
 
141

Winter mushroom mixed nourishment  

UK PubMed Central (United Kingdom)

The invention discloses winter mushroom mixed nourishment, which consists of the following raw materials in percent by weight: 35-55 percent of cottonseed hull, 25-45 percent of rice bran, 10-16 percent of saw dust, 1.5-2 percent of corn stalk powder, 10.5-1 percent of various vitamins B, 0.5-1 percent of soybean protein powder, 0.5-1 percent of lime, 1.5-2 percent of yellow sand, 0.1-0.3 percent of white sugar, 0.1-0.3 percent of milk powder, 0.1-0.3 percent of carbendazim and 0.5-0.8 percent of pesticide. A preparation method of the winter mushroom mixed nourishment comprises the following steps: taking the cottonseed hull, the rice bran, saw dust and the corn stalk powder according to the proportion and combining together crushing the mixture into grains with about 120 meshes taking out the grains and then adding the various vitamins, the soybean protein powder, the lime, the yellow sand, the white sugar, the milk powder, the carbendazim and the pesticide pouring the mixture into a stirrer to stir for 100 minutes and taking out placing the mixture into a fermenting tank adding water according to the ratio of 1:(1.2-1):1.3, uniformly stirring to pile and tightly covering by a thick plastic film and fermenting for 18-24 hours to obtain the qualified nourishment.

SHENGJIAN ZHOU

142

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

International Nuclear Information System (INIS)

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

2012-01-01

143

The physiology of diving in a north-temperate and three tropical turtle species.  

UK PubMed Central (United Kingdom)

We examined changes in blood gases, plasma ions, and acid-base status during prolonged submergence (6 h) of four aquatic turtle species in aerated water at 20 degrees C. Our objective was to determine whether the temperate species, Chrysemys picta bellii, exhibits greater tolerance to submergence apnea than the tropical species, Pelomedusa subrufa, Elseya novaeguineae, and Emydura subglobosa. Blood was sampled from indwelling arterial catheters for measurements of blood PO2, PCO2, pH, and hematocrit and for plasma concentrations of lactate, glucose, Na+, K+, Cl-, total Ca, and total Mg. The pattern of change was similar in all species: a combined respiratory and metabolic acidosis associated with a marked decrease of blood PO2. The severity of the acidosis developed in the temperate species, however, was significantly less than that of the tropical turtles. Lactate rose significantly and HCO3- fell proportionately in all turtles; changes in other plasma ion concentrations were small but were generally in the directions consistent with compensatory exchanges with other body compartments; i.e., cations (K+, Ca, and Mg increased) and anions (Cl- decreased). The results indicate that hypoxia tolerance is a conserved trait in turtles, even in those that do not experience enforced winter submergence, and that the temperate species may be superior in this capacity because of reduced metabolic rate.

Crocker CE; Ultsch GR; Jackson DC

1999-07-01

144

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

145

Mercury emission from a temperate lake during autumn turnover  

International Nuclear Information System (INIS)

Lakes in temperate regions stratify during summer and winter months, creating distinct layers of water differentiated by their physical and chemical characteristics. When lakes mix in autumn and spring, mercury cycling may be affected by the chemical changes that occur during mixing. Sampling was conducted in Lake Lacawac, Eastern Pennsylvania, USA, throughout the autumn of 2007 to characterize changes in emission of gaseous elemental mercury (Hg0) from the lake surface and dissolved mercury profiles in the water column during mixing. Water chemistry and weather parameters were also measured, including dissolved organic carbon (DOC), iron, and solar radiation which have been shown to interact with mercury species. Results indicate that emission of Hg0 from the lake to the atmosphere during turnover was controlled both by solar radiation and by surface water mercury concentration. As autumn turnover progressed through the months of October and November, higher mercury concentration water from the hypolimnion mixed with epilimnetic water, increasing mercury concentration in epilimnetic waters. Dissolved absorbance was significantly correlated with mercury concentrations and with iron, but DOC concentrations were essentially constant throughout the study period and did not exhibit a relationship with either dissolved mercury concentrations or emission rates. Positive correlations between dissolved mercury and iron and manganese also suggest a role for these elements in mercury transport within the lake, but iron and manganese did not demonstrate a relationship with emission rates. This research indicates that consideration of seasonal processes in lakes is important when evaluating mercury cycling in aquatic systems

2009-04-01

146

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 for all PADD's and product supplied on a US level; propane net product supplied on a US level; propane net production, imports and stocks for Petroleum Administration for Defense Districts (PADD) I, II, and III; natural gas supply and disposition and underground storage for the United States and consumption for all PADD's; residential and wholesale pricing data for propane and heating oil 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 United States and selected cities; and US total heating degree-days by city. 27 figs, 12 tabs.

1990-11-29

147

Winter fuels report  

International Nuclear Information System (INIS)

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

1995-01-01

148

Winter fuels report  

Energy Technology Data Exchange (ETDEWEB)

The Winter Fuels Report is intended to provide consise, 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; 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.

1995-02-17

149

SYSTEM AND METHOD FOR PROVIDING TEMPERED FLUID  

UK PubMed Central (United Kingdom)

The present invention is directed to methods and apparatus for tempering the temperature of a liquid in a fluid conducting system. More particularly, the invention relates to temperi ng the temperature of water supplied to a fixture from a water heater in a fluid conducting system.

COOK GARY; EVELEIGH ROBERT

150

"Winter is coming"  

CERN Multimedia

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

151

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

152

Tempering instead of heating; Temperieren statt heizen  

Energy Technology Data Exchange (ETDEWEB)

With the large-volume seasonal heat stores of wieso Wiedemann Solartechnik, Aachen, solar heat can be stored in summer and used for heating in winter. The system is applicable in one- and two-family buildings. [German] Solarwaerme aus den Sommermonaten zum Heizen im Winter nutzen, das ist das Ziel der grossvolumigen Pufferspeicher der Firma wieso Wiedemann Solartechnik in Aachen. Ein System auch fuer Ein- und Zweifamilienhaeuser. (orig.)

Goerke, U.

2001-12-07

153

Monitoring Rehabilitation in Temperate North American Estuaries  

Energy Technology Data Exchange (ETDEWEB)

In this chapter, we propose that monitoring rehabilitation in estuarine ecosystems by necessity requires quantifying relationships between dynamic estuarine processes and sensitive indicators of ecosystem function. While we do discuss temperate systems in general, emphasis is placed on anadromous salmon habitats in the Pacific Northwest because anadromous fishes are such a major focus of rehabilitation efforts, and present some of the greater challenges in linking function of one segment of their life history to conditions in a specific habitat. We begin with a basic overview of the ecological and socioeconomic significance of, as well as anthropogenic effects on, estuaries. Next, we briefly summarize the various kinds of estuarine rehabilitation historically practiced in temperate regions, and review estuarine rehabilitation monitoring design and methods, highlighting the unique challenges involved in monitoring estuarine systems. We then close with a summary and conclusions.

Rice, Casimir A.; Hood, W Gregory; Tear, Lucinda M.; Simenstad, Charles; Williams, Gregory D.; Johnson, L. L.; Feist, B. E.; Roni, P.

2005-02-01

154

The Challenge of Winter Backpacking.  

Science.gov (United States)

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

Cavanaugh, Michael; Mapes, Alan

1981-01-01

155

Grazing Management of Temperate Grasslands and Fallows  

Directory of Open Access Journals (Sweden)

Full Text Available The paper provides a general overview of fodder resources andtheir management in temperate Bhutan (altitude range of1500-3000m). The terms are used as defined by RC-Jakar(RNR-RC-Jakar, 1996). As per these definitions, temperatepasture can include any kind of land used for grazing. Whenreferring to registered grassland or tsamdro, only the termtsamdrog is used. Where possible, the term pasture isreplaced with more specific or more appropriate terms.

Walter Roder

2002-01-01

156

ACHIEVEMENTS IF WINTER PEA BREEDING ?????????? ? ???????? ????????? ??????  

Directory of Open Access Journals (Sweden)

Full Text Available Winter pea is being bred at Krasnodar in the Research Institute of Agriculture of the Russian Academy of Agricultural Sciences. An alternative pea variety Legion has been bred and included into the National List of Varieties. The article presents the description of the first winter leafless pea varieties - Zimus and Fokus, which have been passed to the National Variety Testing System in 2011

Brezhneva V. I.; Miroshnichenko A. N.; Brezhnev A. V.

2012-01-01

157

The meaning of nuclear winter  

International Nuclear Information System (INIS)

In this paper the author reviews the history and origins of the basic ideas underlying nuclear winter; and findings and predictions of several groups regarding this topic. The author reviews some of the further developments and scientific analyses regarding nuclear winter since the initial announcements of 1983, touching on some of the revisions and controversies and trying to indicate the current status of the field.

1987-01-01

158

Leaf out phenology in temperate forests  

Directory of Open Access Journals (Sweden)

Full Text Available Monitoring phenology, the study of the timing of natural events, is an ancient practice that has experienced renewed relevance for scientific research interest in the wake of awareness of anthropogenic climate change. Spring onset has been occurring significantly earlier in temperate regions worldwide. Leaf out phenology has become particularly well studied is of particular interest because the emergence of leaves in the spring is extremely sensitive to temperature, and the leaf out timing of leaf out in temperate ecosystems marks the onset of the growing season and controls many essential ecosystem processes. This article reviews the current literature concerning the different methods used to study leaf out phenology, the controls on leaf out in temperate woody plants, and the effects of climate change on leaf out phenology. In addition to the traditional method of on-the-ground leaf out monitoring, new methods using remote sensing and dedicated cameras have been developed which allow scientists to track spring onset at a much larger scale than hadpreviously been possible. Further work is needed on how leaf phenology will respond to future climate change, and the implications of this for animals and other species interactions among trophic levels.

Caroline A. Polgar; Richard B. Primack

2013-01-01

159

Ecological niche study of constructive species of the vegetation ecotone of temperate grassland and warm--temperate deciduous broad-leaved forest-----Taking the vegetation on the south and north slopes of Heng Mts.Shanxi for example  

UK PubMed Central (United Kingdom)

Heng Mts.,Shanxi is located in the ecotone of temperate grassland zone and warm-temperate deciduous broad-leaved forest zone according to China Vegetation Regionalization.Adopting Shannon-Wiener,the niche breadth index,the article classified constructive species on both slopes into 3 ecologic groups respectively.Artemisia brachyloba,Dendranthema chanetii,Carex lanceolata and Sanguisorba alpina of the south slope,and Carex lanceolata,Denfranthema zawwadskii,Poa sphondyloes,Siline jenisseensis and Sanguisorba alpina of the north slope occupy a broader niche, showing an apparent niche generalization. By contrast, Potentilla anserine, Spiraea trilobata, Ostryopsis davidiana and Hippophae rhamnoides subsp. sinensis of the south slope, Stipa bungeana, Puccinellia distans, Artemisia brachyloba, Polygonum viviparum, Anaphalis hancockii, Spiraea trilobata, Hippophae rhamnoides subsp. sinensis and Populus cathayana of the north slope occupy a much narrower niche, which is closely related to their environment. The 16 constructive populations of the south slope form 240 species counterparts, among which 100, that's 41.9% of the total, have niche overlaps, indicating that there exits niche overlap among the 16 species of the south slope. The 21 constructive populations of the north slope form 420 species counterparts, among which 69, that's 16.4% of the total, have niche overlaps, indicating that there does not exit an apparent niche overlap among the 21 species. The apparent separation in ecologic niche among populations suggests a significant difference as to their utility of recourses. All of the above are caused by the evenness the south slope while the sheerness the north, which leads to a continuous spreading of vegetation on the south and many discontinuities making overlap an rare occurrence on the north because ofmuch sharper rise of elevation. By an overall comparison and contrast of niche breadth and niche overlap of the constructive species of each slope, an establishment of Hengshan Mts. as the borderline between temperate grassland zone and warm-temperate deciduous broad-leaved forest zone can achieved more objectively.

Ma Xiaoyong; Shangguan Tieliang; Zhang Feng

2006-01-01

160

Aeolian Zone.  

UK PubMed Central (United Kingdom)

It is postulated that a widespread biotic zone, based on wind-blown organic materials such as pollen and oceanic albuminoids, exists in mountainous and polar regions. The aeolian zone or biome, distinct from alpine and arctic tundra, may be divided into terrestrial, nival, and aquatic divisions.

Swan LW

1963-04-01

 
 
 
 
161

Tempering mechanism of solid-fat products. Kokei yushi seihin no tempering kiko  

Energy Technology Data Exchange (ETDEWEB)

Untemered margarine and butter as test pieces and a reference specimen (made up of cacao fat at 30% by weight and soya bean oil at 70% by weight), as well as those applied with tempering treatment are prepared. The solid content in the test pieces and the temperature dependency of particles sizes (in the range from 10 to 25 {degree} C) were measured using the permeability method developed by the authors, and their histological structures were observed using SEM. The result shows the following: (1) When the temperature of the untempered products is raised, the grain size in solid particles decreases suddenly at a certain temperature; (2) The tempered test pieces had their solid content and grain sizes decreased and the number of particles increased largely as compared with the untempered products; and (3) The solid particles being coagulates of micro particles present in the untempered products are destroyed by the tempering treatment, turning into dispersed micro particles. 7 refs., 9 figs.

Hirokawa, N. (Kanegafuchi Chemical Industry Co. Ltd., Osaka (Japan)); Harano, Y. (Fukuyama University, Hiroshima (Japan). Faculty of Engineering)

1991-08-20

162

The effect of tempering temperature on near- threshold fatigue crack behavior in quenched and tempered 4140 steel  

Science.gov (United States)

Fatigue crack growth in compact tension samples of high purity 4140 steel quenched and tempered to various strength levels was investigated. Tempering temperatures of 200, 400, 550, and 700 °C produced yield strengths from 1600 to 875 MPa, respectively. Crack propagation and crack closure were monitored in K-decreasing tests performed under R = 0.05 loading conditions in laboratory air. Results indicated that as the yield strength increased the crack growth rate increased at a given ?K and ?Kth decreased. Threshold values varied from 2.8 MPa m1/2 (200 °C temper) to 9.5 MPa m1/2 (700 °C temper). Cracks in the 200 °C tempered samples grew by an intergranular mechanism following prior austenite grain boundaries probably caused by hydrogen embrittlement or tempered martensite embrittlement. Tempering above 200 °C produced transgranular fatigue crack growth. The level of crack closure increased with tempering temperature and with crack propagation in a given tempered condition. Crack closure was caused by a combination of plasticity-induced and oxide-induced mechanisms. The use of an effective stress intensity range based on crack closure consolidated the fatigue crack growth curves and the threshold values for all tempering temperatures except 200 °C.

London, B.; Nelson, D. V.; Shyne, J. C.

1988-10-01

163

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

Science.gov (United States)

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

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

2001-01-01

164

Comparing the carbon budgets of boreal and temperate deciduous forest stands  

Energy Technology Data Exchange (ETDEWEB)

Three years of eddy-covariance flux measurements from two deciduous forest stands were compared, one from a temperate mixed wood stand at Camp Borden, Ontario, and one from a boreal aspen stand near Prince Albert, Saskatchewan. The objective was to gain increased understanding of the processes that control net ecosystem productivity (NEP) and to contrast the responses of boreal and temperate deciduous forest ecosystems to interannual climatic variability. Results showed that in the boreal ecosystem, interannual differences in NEP were primarily controlled by early spring temperatures. Whereas the warm spring temperatures which caused early leaf out and increased photosynthesis but no effect on respiration in the boreal zone, resulted only in early leaf out but also in increased respiration and drought stress in the temperate ecosystem. The contrasting impact of the warm spring temperatures on annual NEP at the two sites illustrates the complexity of interpreting climatic impacts on the forest carbon balance. It is likely that warmer temperatures and drier soil conditions impact differently on ecosystem respiration and ecosystem photosynthesis. They may also have different impacts on growth and maintenance respiration versus soil microbial respiration. 33 refs., 3 tabs., 5 figs.

Barr, A. G. [Environment Canada, Meteorological Service of Canada, Climate Research Branch, Sakatoon, SK (Canada); Griffis, T. J.; Black, T. A.; Chen, Z.; Morgenstern, K. [British Columbia Univ., Dept of Agricultural Science, Vancouver, BC (Canada); Lee, X. [Yale Univ., School of Forestry and Environmental Studies, New Haven, CT (United States); Staebler, R. M. [Environment Canada, Meteorological Service of Canada, Air Quality Research Branch, Downsview, ON (Canada); Fuentes, J. D. [Virginia Univ. Dept. of Environmental Sciences, Charlottesville, VA (United States)

2002-05-01

165

Prolonged residence of temperate natives in the tropics produces a suppression of sweating.  

Science.gov (United States)

Tropical natives possess heat tolerance due to the ability to off-load endogenous and exogenous heat efficiently using a minimum amount of sweat. On the other hand, exposure of temperate natives to heat results in exaggerated production of sweat, of which part is lost by dripping and, thus, not available for evaporation. How sweating is modified in natives of temperate climate zones by prolonged residence in the tropics is not well-understood. The aim of this study was to investigate possible changes in the peripheral sweating mechanisms. Sweating responses to iontophoretically applied acetylcholine (ACh) were compared between Japanese subjects having either permanently resided in Japan (Japan resident Japanese, JRJ) or having stayed in the tropics for 2 years or longer (Tropics resident Japanese, TRJ). Quantitative sudomotor axon reflex tests by iontophoresis of ACh (10%, 2 mA for 5 min) were applied to determine directly activated (DIR) and axon reflex-mediated sweating during [AXR(1)] and after [AXR(2)] ACh iontophoresis. The sweat onset time of AXR(1) was 0.6 min shorter in JRJ than in TRJ (PAXR(1) (PAXR(2) (PAXR and DIR sweating volumes (P<0.0001) were negatively correlated, and sweat onset times (P<0.0001) were positively correlated with the duration of residence in the tropics (2 to 13 years). The observed attenuation of sweating in TRJ suggests that temperate natives may acquire heat tolerance with improved sweating economy similar to tropical natives after prolonged residence in the tropics. PMID:16736205

Bae, Jun-Sang; Lee, Jeong-Beom; Matsumoto, Takaaki; Othman, Timothy; Min, Young-Ki; Yang, Hun-Mo

2006-05-31

166

Denitrification and dissimilatory nitrate reduction to ammonium (DNRA) in a temperate re-connected floodplain.  

Science.gov (United States)

The relative magnitudes of, and factors controlling, denitrification and dissimilatory nitrate reduction to ammonium (DNRA) were measured in the soil of a re-connected temperate floodplain divided into four different land management zones (grazing grassland, hay meadow, fritillary meadow and a buffer zone). Soil samples were collected from each zone to measure their respective potentials for nitrate attenuation using 15N both at the surface and at depth in the soil column and additional samples were collected to measure the lability of the organic carbon. Denitrification capacity ranged between 0.4 and 4.2 (?mol N g(-1) dry soil d(-1)) across the floodplain topsoil and DNRA capacity was an order of magnitude lower (0.01-0.71 ?mol N g(-1) d(-1)). Land management practice had a significant effect on denitrification but no significant effects were apparent for DNRA. In this nitrogen-rich landscape, spatial heterogeneity in denitrification was explained by differences in lability and the magnitude of organic carbon associated with different management practices (mowing and grazing). The lability of organic carbon was significantly higher in grazing grassland in comparison to other ungrazed areas of the floodplain, and consequently denitrification capacity was also highest in this area. Our results indicate that bacteria capable of DNRA do survive in frequently flooded riparian zones, and to a limited extent, compete with denitrification for nitrate, acting to retain and recycle nitrogen in the floodplain. Exponential declines in both denitrification and DNRA capacity with depth in the floodplain soils of a hay meadow and buffer zone were controlled primarily by the organic carbon content of the soils. Furthermore, grazing could be employed in re-connected, temperate floodplains to enhance the potential for nitrate removal from floodwaters via denitrification. PMID:21813153

Sgouridis, F; Heppell, C M; Wharton, G; Lansdown, K; Trimmer, M

2011-07-08

167

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 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 (more) . 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 based on negative binomial regressions, vital statistics and the results of weekly influenza virus surveillance. FINDINGS: Annual influenza-associated excess mortality, for all cau (more) ses, 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.

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

2012-04-01

168

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

UK PubMed Central (United Kingdom)

The obligate mutualism between leafcutter ants and their Attamyces fungi originated 8 to 12 million years ago in the tropics, but extends today also into temperate regions in South and North America. The northernmost leafcutter ant Atta texana sustains fungiculture during winter temperatures that would harm the cold-sensitive Attamyces cultivars of tropical leafcutter ants. Cold-tolerance of Attamyces cultivars increases with winter harshness along a south-to-north temperature gradient across the range of A. texana, indicating selection for cold-tolerant Attamyces variants along the temperature cline. Ecological niche modeling corroborates winter temperature as a key range-limiting factor impeding northward expansion of A. texana. The northernmost A. texana populations are able to sustain fungiculture throughout winter because of their cold-adapted fungi and because of seasonal, vertical garden relocation (maintaining gardens deep in the ground in winter to protect them from extreme cold, then moving gardens to warmer, shallow depths in spring). Although the origin of leafcutter fungiculture was an evolutionary breakthrough that revolutionized the food niche of tropical fungus-growing ants, the original adaptations of this host-microbe symbiosis to tropical temperatures and the dependence on cold-sensitive fungal symbionts eventually constrained expansion into temperate habitats. Evolution of cold-tolerant fungi within the symbiosis relaxed constraints on winter fungiculture at the northern frontier of the leafcutter ant distribution, thereby expanding the ecological niche of an obligate host-microbe symbiosis.

Mueller UG; Mikheyev AS; Hong E; Sen R; Warren DL; Solomon SE; Ishak HD; Cooper M; Miller JL; Shaffer KA; Juenger TE

2011-03-01

169

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

UK PubMed Central (United Kingdom)

The northeastern forest region of China is an important component of total temperate and boreal forests in the northern hemisphere. But how carbon (C) pool size and distribution varies among tree, understory, forest floor and soil components, and across stand ages remains unclear. To address this knowledge gap, we selected three major temperate and two major boreal forest types in northeastern (NE) China. Within both forest zones, we focused on four stand age classes (young, mid-aged, mature and over-mature). Results showed that total C storage was greater in temperate than in boreal forests, and greater in older than in younger stands. Tree biomass C was the main C component, and its contribution to the total forest C storage increased with increasing stand age. It ranged from 27.7% in young to 62.8% in over-mature stands in boreal forests and from 26.5% in young to 72.8% in over-mature stands in temperate forests. Results from both forest zones thus confirm the large biomass C storage capacity of old-growth forests. Tree biomass C was influenced by forest zone, stand age, and forest type. Soil C contribution to total forest C storage ranged from 62.5% in young to 30.1% in over-mature stands in boreal and from 70.1% in young to 26.0% in over-mature in temperate forests. Thus soil C storage is a major C pool in forests of NE China. On the other hand, understory and forest floor C jointly contained less than 13% and <5%, in boreal and temperate forests respectively, and thus play a minor role in total forest C storage in NE China.

Wei Y; Li M; Chen H; Lewis BJ; Yu D; Zhou L; Zhou W; Fang X; Zhao W; Dai L

2013-01-01

170

Ion exchange tempering of glass ophthalmic lenses.  

Science.gov (United States)

We performed low velocity drop-ball tests using 5/8-, 7/8-, and 1-inch diameter steel balls on ophthalmic crown glass lenses chemically tempered by the ion exchange process. Four representative dioptric strengths (+ 2.50 spherical, - 2.50 spherical, -2.50 cylindrical, and plano) were studied with the isolated lenses mounted, convex side up, on the American National Standards Institute Z80 test block. New ion exchange lenses exhibited a 100 to 350% greater capacity for attenuation of energy from low velocity, large size missiles than matched lenses of similar strength prepared by the conventional heat-treating and air-quenching process. PMID:1155569

Keeney, A H; Duerson, H L

1975-08-01

171

Ion exchange tempering of glass ophthalmic lenses.  

UK PubMed Central (United Kingdom)

We performed low velocity drop-ball tests using 5/8-, 7/8-, and 1-inch diameter steel balls on ophthalmic crown glass lenses chemically tempered by the ion exchange process. Four representative dioptric strengths (+ 2.50 spherical, - 2.50 spherical, -2.50 cylindrical, and plano) were studied with the isolated lenses mounted, convex side up, on the American National Standards Institute Z80 test block. New ion exchange lenses exhibited a 100 to 350% greater capacity for attenuation of energy from low velocity, large size missiles than matched lenses of similar strength prepared by the conventional heat-treating and air-quenching process.

Keeney AH; Duerson HL Jr

1975-08-01

172

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; Stephenson SL

2012-01-01

173

Drought-deciduous behavior reduces nutrient losses from temperate deciduous trees under severe drought.  

UK PubMed Central (United Kingdom)

Nutrient resorption from senescing leaves is an important mechanism of nutrient conservation in temperate deciduous forests. Resorption, however, may be curtailed by climatic events that cause rapid leaf death, such as severe drought, which has been projected to double by the year 2100 in the eastern United States. During a record drought in the southeastern US, we studied 18 common temperate winter-deciduous trees and shrubs to understand how extreme drought affects nutrient resorption of the macronutrients N, P, K, and Ca. Four species exhibited drought-induced leaf senescence and maintained higher leaf water potentials than the remaining 14 species (here called drought-evergreen species). This strategy prevented extensive leaf desiccation during the drought and successfully averted large nutrient losses caused by leaf desiccation. These four drought-deciduous species were also able to resorb N, P, and K from drought-senesced leaves, whereas drought-evergreen species did not resorb any nutrients from leaves lost to desiccation during the drought. For Oxydendrum arboreum, the species most severely affected by the drought, our results indicate that trees lost 50% more N and P due to desiccation than would have been lost from fall senescence alone. For all drought-deciduous species, resorption of N and P in fall-senesced leaves was highly proficient, whereas resorption was incomplete for drought-evergreen species. The lower seasonal nutrient losses of drought-deciduous species may give them a competitive advantage over drought-evergreen species in the years following the drought, thereby impacting species composition in temperate deciduous forests in the future.

Marchin R; Zeng H; Hoffmann W

2010-08-01

174

Estimativa de horas de frio abaixo de 7 e de 13°C para regionalização da fruticultura de clima temperado no estado de São Paulo/ Temperate fruit crop zoning in the State of São Paulo - Brazil based upon estimated number of hours with temperature below 7 and 13°C  

Scientific Electronic Library Online (English)

Full Text Available Abstract in portuguese Estimativa e mapeamento do número de horas com temperaturas abaixo de 7 e 13°C no Estado de São Paulo e análise comparativa do comportamento de fruteiras de clima temperado constituem os objetivos do presente trabalho. Foi cotado o número de horas com temperaturas inferiores a 7 e 13°C, índices considerados limites necessários à dormência dessas plantas. Foram selecionados termogramas de doze postos agrometeorológicos do Instituto Agronômico, situados em (more) altitudes variáveis entre 25 e 1.000m, correspondentes ao período 1964-1973. Estabeleceram-se equações para estimativa do número de horas com temperaturas inferiores a 7°C (HF-7) e 13°C (HF-13) em função da temperatura média do mês de julho, cujos coeficientes de correlação foram de -0,88 e -0,93, respectivamente. Com base nessas equações foram mapeadas as isolinhas de HF-7 e HF-13 para o Estado de São Paulo, encontrando-se desde valores médios anuais de HF-7 inferiores a 20 horas, característicos das regiões de transição de clima mesotérmico a megatérmico do Planalto Ocidental e das regiões mais baixas do norte e oeste do Estado, até valores anuais de HF-7 superiores a 200 horas, característicos das áreas acima de 1.500 metros de altitude no Sul do Estado, na serra da Mantiqueira, limítrofe com Minas Gerais, e na serra do Mar, limítrofe com o Rio de Janeiro. Com base na introdução de diferentes frutíferas de clima temperado no Estado de São Paulo, verificou-se uma relação muito grande entre os índices HF-7 e HF-13 mapeados com o comportamento e potencialidade de exploração comercial. Abstract in english The behavior of temperate climate fruit crops in the State of São Paulo - Brazil as function of "dormancy units" (DAMARIO, 1969) was analysed with the object of providing a simple method for mapping areas with aptitude for commercial development of the crop trees. Thermographs from 12 agrometeorological stations located at altitudes varying from 25 to 1000 meters above sea level and corresponding to the period 1964-1973 were analysed. The number of hours with temperature (more) s below 7 and 13°C, obtained from the diagrams, were correlated with the mean temperature of July, the coldest month, with correlation coeficients equal to -0.88 and -0.93, respectively. Regression equations, were used for mapping the isolines of "dormancy units" for both base temperatures. It was shown that the total period with temperature below 7°C is variable from 20 to more than 200 hours as the altitude increases. A good agreement between commercial exploitation of the crops and the chilling period was also observed.

Pedro Júnior, Mário J.; Ortolani, Altino Aldo; Rigitano, Orlando; Alfonsi, Rogério Remo; Pinto, Hilton Silveira; Brunini, Orivaldo

1979-01-01

175

Climatic records over the past 30 ka from temperate Australia – a synthesis from the Oz-INTIMATE workgroup  

Science.gov (United States)

Temperate Australia sits between the heat engine of the tropics and the cold Southern Ocean, encompassing a range of rainfall regimes and falling under the influence of different climatic drivers. Despite this heterogeneity, broad-scale trends in climatic and environmental change are evident over the past 30 ka. During the early glacial period (˜30–22 ka) and the Last Glacial Maximum (˜22–18 ka), climate was relatively cool across the entire temperate zone and there was an expansion of grasslands and increased fluvial activity in regionally important Murray–Darling Basin. The temperate region at this time appears to be dominated by expanded sea ice in the Southern Ocean forcing a northerly shift in the position of the oceanic fronts and a concomitant influx of cold water along the southeast (including Tasmania) and southwest Australian coasts. The deglacial period (˜18–12 ka) was characterised by glacial recession and eventual disappearance resulting from an increase in temperature deduced from terrestrial records, while there is some evidence for climatic reversals (e.g. the Antarctic Cold Reversal) in high resolution marine sediment cores through this period. The high spatial density of Holocene terrestrial records reveals an overall expansion of sclerophyll woodland and rainforest taxa across the temperate region after ˜12 ka, presumably in response to increasing temperature, while hydrological records reveal spatially heterogeneous hydro-climatic trends. Patterns after ˜6 ka suggest higher frequency climatic variability that possibly reflects the onset of large scale climate variability caused by the El Niño/Southern Oscillation.

Petherick, L.; Bostock, H.; Cohen, T. J.; Fitzsimmons, K.; Tibby, J.; Fletcher, M.-S.; Moss, P.; Reeves, J.; Mooney, S.; Barrows, T.; Kemp, J.; Jansen, J.; Nanson, G.; Dosseto, A.

2013-08-01

176

SYSTEM AND METHOD FOR PROVIDING A TEMPERED FLUID  

UK PubMed Central (United Kingdom)

The present invention is directed to methods and apparatus for tempering thetemperature of a liquid in a fluid conducting system. More particularly, theinvention relates to tempering the temperature of water supplied to a fixturefrom a water heater in a fluid conducting system.

EVELEIGH Robert; COOK Gary

177

Contribution to the modelling of chocolate tempering process.  

Digital Repository Infrastructure Vision for European Research (DRIVER)

The tempering of chocolate, i.e. the process of crystallization of the desired morph; is a key step in its manufacturing by professional chocolatiers. In this work, a model of a tempering process based on seeding with solid chocolate grains is developed to enhance understanding and control of the sy...

Debaste, Frédéric; Kegelaers, Yves; Ben Amor, Hatem; Halloin, Véronique

178

Limit Theorems For Sequences of Tempered Stable and Related Distributions  

CERN Multimedia

In this paper we define the closure under weak convergence of the class of p-tempered {\\alpha}-stable distributions. We give necessary and sufficient conditions for convergence of sequences in this class. Moreover, we show that any element in this class can be approximated by the distribution of a linear combination of elementary p-tempered {\\alpha}-stable random variables.

Grabchak, Michael

2012-01-01

179

Interactions of Lactobacillus bulgaricus Temperate Bacteriophage 0448 with Host Strains  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Lactobacillus bulgaricus LT4(0448) is a lysogenic strain from which a temperate bacteriophage can be induced by mitomycin C or UV irradiation. Lactobacillus lactis CNRZ 326 is an indicator strain for the temperate phage 0448, but this strain lyses only in the presence of Ca2+ ions. A resistant cultu...

Cluzel, Pierre-Jean; Serio, Jacques; Accolas, Jean-Pierre

180

Temperature influences whole-animal rates of metabolism but not protein synthesis in a temperate intertidal isopod.  

Science.gov (United States)

The effects of temperature on two important biological rate processes, whole-body rates of oxygen uptake (M dot o2) and protein synthesis (k(s)), were investigated in the temperate intertidal isopod Ligia oceanica at two different times of the year. Animals were collected in January (winter) and June (summer) and either subjected to an acute temperature change after 24 h (acclimatized) or acclimated to various temperatures for 4 wk. In both cases, M dot o2 increased with temperature, with a Q(10) of 2.2 between 5 degrees and 20 degrees C, but increased in thermal sensitivity at 25 degrees C. Winter isopods were characterized by significantly higher M dot o2 levels, greater thermal sensitivities, and lower thermal tolerances than summer animals. Seasonal differences in M dot o2 persisted after acclimation, indicating that temperature alone was not responsible for the changes. In sharp contrast, whole-body k(s) showed no variation with temperature, although overall rates decreased upon acclimation. In acclimatized animals, k(s) was higher in the summer than in the winter. After acclimation, a compensatory increase in RNA capacity in winter animals reversed this situation. The temperature independence of whole-body k(s) in L. oceanica could ensure survival in a highly liable thermal environment, as thermal tolerances of intertidal invertebrates are thought to be more closely related to protein than to energy metabolism. PMID:15778942

Whiteley, Nia; Faulkner, L S

2005-03-03

 
 
 
 
181

Apparatus for continuous tempering of cacao-butter-containing or other fatcontaining chocolate-like mass  

UK PubMed Central (United Kingdom)

An apparatus (1) for continuous tempering of cacao-butter-containing or other fat-containing, chocolate-like mass flowing therethrough. In the apparatus (1) a predetermined, controlled cooling- or heating-stage of the mass is provided. The apparatus (1) comprises a cooling zone (2) with a plurality of cooling surfaces (3), and a subsequent heating zone (4) with a plurality of heating surfaces (5) for the mass during its passage through at least two sections (C1-Cn; H1-Hn). The sections comprises mass treatment chambers (6) in succession with associated cooling- or heating medium chambers (7,8). According the invention there is in relation to said sections (C1-Cn; H1-Hn) of mass treatment chambers (6) arranged at least one heat transmission barrier (9). During operation of the apparatus (1) the heat transmission barrier (9) reduces the heat transmission between the sections (C1-Cn; H1-Hn) in between which it is arranged to an essentially eliminating and almost imperceptible level. A substantially better controlled tempering process is therefore provided inside a specific section (C1-Cn; H1-Hn).

Aasted Lars

182

On the transgranular type of tempered martensite embrittlement  

International Nuclear Information System (INIS)

[en] Martensitic alloy steels are subject to tempering because of their low toughness in the as-quenched state. When tempered in the range of 250--400 C, however, the toughness drops in spite of the decrease in strength with increasing the tempering temperature. This phenomenon is referred to as tempered martensite embrittlement (TME). TME can be classified into two types according to the fracture mode; intergranular and transgranular TME. The transgranular type was suggested to be caused by the formation of coarse carbides at the lath boundaries following the decomposition of retained austenite. In this study, the transgranular type of TME has been analyzed in terms of impact toughness, fracture behavior and microstructure on isothermal tempering. The experimental alloy systems chosen are the Mo and MoW steels in which alloying elements, Mo and W, may decrease the intrinsic toughness and thus produce easy transgranular brittle fracture

1994-05-01

183

On the transgranular type of tempered martensite embrittlement  

Energy Technology Data Exchange (ETDEWEB)

Martensitic alloy steels are subject to tempering because of their low toughness in the as-quenched state. When tempered in the range of 250--400 C, however, the toughness drops in spite of the decrease in strength with increasing the tempering temperature. This phenomenon is referred to as tempered martensite embrittlement (TME). TME can be classified into two types according to the fracture mode; intergranular and transgranular TME. The transgranular type was suggested to be caused by the formation of coarse carbides at the lath boundaries following the decomposition of retained austenite. In this study, the transgranular type of TME has been analyzed in terms of impact toughness, fracture behavior and microstructure on isothermal tempering. The experimental alloy systems chosen are the Mo and MoW steels in which alloying elements, Mo and W, may decrease the intrinsic toughness and thus produce easy transgranular brittle fracture.

Kon Bae Lee; Sang Hoon Yoon; Hoon Kwon (Kookmin Univ., Seoul (Korea, Republic of). Dept. of Metallurgy and Materials Engineering)

1994-05-01

184

Effect of rare earths on cold brittleness and temper brittleness and temper brittleness of structural steels  

International Nuclear Information System (INIS)

[en] The following problems are discussed: the possibility to bind phosphorus in steel with rare-earth metals and concentrations of these metals; the effect produced on mechanical properties of steels at static and dynamic tests. The study has been made on the 35KhGS and 38KhS steels prone to reversible temper brittleness. It is shown that small practically adopted (up to 0.15%) additions of rare-earth metals to structural steels do not produce any significant effect on the position of cold brittleness threshold after improvement and additional embrittling tempering. Alloying Cr-Mn-Si steels with large additions of rare-earth metals (0.40 to O.65%) shifts the cold brittleness threshold of the improved steel by more than 100 deg C towards the region of low temperatures and practically eliminates its tendency to reversible temper brittleness. It has been established as a result of micro-X-ray spectrum studies that rare-earth metals do not produce alloying effect on the solid solution and do not enrich grain boundaries but can be found as a whole in nonmetallic inclusions. It is demonstrated that the main reason for the considerably lower cold brittleness threshold in the alloying with large additions of rare-earth metals lies in the fact that they bind phosphorus and its analogues into nonmetallic inclusions

1977-02-24

185

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

186

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

Science.gov (United States)

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)D Wh(-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)D Wh(-1) (summer, Amphibolis) to 0.69 mg N g(-1)DWh(-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. PMID:20739251

Nayar, S; Collings, G J; Miller, D J; Bryars, S; Cheshire, A C

2010-06-08

187

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

UK PubMed Central (United Kingdom)

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)D Wh(-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)D Wh(-1) (summer, Amphibolis) to 0.69 mg N g(-1)DWh(-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.

Nayar S; Collings GJ; Miller DJ; Bryars S; Cheshire AC

2010-09-01

188

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

189

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

International Nuclear Information System (INIS)

[en] 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

1979-01-01

190

Red knots give up flight capacity and defend food processing capacity during winter starvation  

UK PubMed Central (United Kingdom)

1. During the last phase of starvation, animals depend mainly on protein breakdown. All organs are a potential protein source. Do starving animals prevent particular organs from being catabolized in order to defend certain functions? In this study we investigated if starving birds maintain locomotion and digestion capacities, both essential for the recovery process. 2. We compared body composition data of healthy wintering and winter-starved red knots (Calidris canutus islandica), a long-distance migrating shorebird that breeds on High Arctic tundra in Canada and Greenland, and winters in temperate coastal areas such as the Wadden Sea and the British estuaries. Throughout the wintering period they eat hard-shelled molluscs ingested whole. 3. Our results showed that winter-starved knots had catabolized 60·5% of their pectoral muscles. This was much more than the decrease in overall body mass (32·5%). As a result, their flight capacities will have been reduced. 4. Winter-starved knots defended the muscular gizzard, which lost only 21·2% of its mass. As knots crack the ingested shellfish with their gizzard, the organ is essential for food processing. The intestines and liver were not defended; their atrophy equalled that of the pectoral muscles (60·6% and 61·3%, respectively). 5. Comparison with data from the literature led to the conclusion that starving birds only defend organs that are essential to either obtain or process food. These organs are maintained at the minimal level of normal capacity. Other organs decrease below this level and may lose much of their functional capacity. 6. Even in near-death situations, with low fitness prospects, organisms show interpretably adaptive changes in organ size.

DIETZ MAURINEW; PIERSMA THEUNIS

2007-10-01

191

Hypometabolism and basking: the strategies of Alpine ibex to endure harsh over-wintering conditions  

UK PubMed Central (United Kingdom)

1. The extent to which free-ranging large north-temperate mammals seasonally adjust thermoregulation and their energy expenditure under fully natural conditions are unknown. 2. Therefore, using telemetry we measured the heart rate (as a proxy for metabolic rate), rumen temperature (Tr) and locomotor activity (LA) over 2 years for 20 free-ranging Alpine ibex (Capra ibex ibex) living at high altitudes in the Alps. 3. Ibex showed strong seasonal changes in mean daily heart rate with a winter nadir of about 60% below the summer peak. Only 40% of this variation could be attributed to the changes in daily mean Tr, LA, wind chill, body size and snowfall. The unexplained residual variation in heart rate still showed a strong seasonal pattern. 4. The amplitude of daily rhythms in Tr was twice as high during the winter when compared with summer. This was predominantly due to lower daily minimum Tr. Thus, the substantial down-regulation of endogenous heat production during winter - as indicated by heart rate - had surprisingly small effects on Tr, indicating decreased thermal conductance. 5. Rewarming from the daily Tr minimum during the morning hours was independent of heart rate throughout the year, and occurred phase-delayed to the increase in black bulb temperature (BBT). The effects of BBT and LA on the rate of rewarming were maximized within a small range of BBT around 0 °C. This suggests that the ibex moved at sunrise to the closest sunny spot to facilitate extensive basking. 6. The energetic benefits of basking can explain the strong residual seasonality of heart rate in Alpine ibex. This partially ectothermic strategy - together with metabolic depression - apparently enables a thrifty use of body fat reserves, the major metabolic fuel during winter, and thus survival of extremely harsh winter conditions despite the virtual absence of food. Therefore, hypometabolism and passive rewarming by basking may be of general importance as a strategy for non-hibernating mammals to survive winter in strongly seasonal habitats.

Signer C; Ruf T; Arnold W

2011-06-01

192

Optimum condition of thermal cycle for temper bead weld repair of SQV2A pressure vessel steel. Fundamental investigation in Gleeble simulation test  

International Nuclear Information System (INIS)

Temper bead welding technique is one of the most important repair welding methods for large structures for which post weld heat treatment (PWHT) is difficult to perform. In this study the optimum condition of weld thermal cycles to carry out temper bead weld repair for pressure vessel steel SQV2A are investigated taking interest in the improvement of the characteristics of coarse grained heat affected zone (CGHAZ) re-heated to the temperature between 670degC (Acl temperature) and 837degC (Ac3 temperature). Thermal/mechanical simulator Gleeble 1500 is employed to give specimens repeated thermal cycles. Improvability of the Charpy absorbed energy and the hardness for the thermal cycles is discussed. The temper bead thermal cycles were suggested that the peak temperature in the second thermal cycle should be selected as lower than Acl but near Acl. In this case triple thermal cycles temper bead process are enough to improve the characteristics of CGHAZ. When the other peak temperatures (that is, higher than Acl) in the succeeding thermal cycle are applied to CGHAZ, quadruple or more thermal cycle temper bead process should be applied. (author)

2003-01-01

193

Diffusion and relaxation controlled by tempered alpha-stable processes.  

UK PubMed Central (United Kingdom)

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.

Stanislavsky A; Weron K; Weron A

2008-11-01

194

Diffusion and Relaxation Controlled by Tempered \\alpha-stable Processes  

CERN Multimedia

We derive general properties of anomalous diffusion and nonexponential relaxation from the theory of tempered \\alpha-stable processes. Its most important application is to overcome the infinite-moment difficulty for the \\alpha-stable random operational time \\tau. The tempering results in the existence of all moments of \\tau. 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, the mean square displacement and the relaxation function. This model includes subdiffusion as a particular case.

Stanislavsky, Aleksander; Weron, Aleksander; 10.1103/PhysRevE.78.051106

2011-01-01

195

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

2008-11-11

196

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 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)

2009-01-01

197

Characterization of tempered martensite embrittlement using hardness measurement  

Energy Technology Data Exchange (ETDEWEB)

A series of experiments were carried out on three commercial steels to explore the possibility for characterizing tempered martensite embrittlement (TME) by Rockwell, macro- and micro-Vickers hardness tests. The results indicate distinct hardness peaks in two steels and an inflection in the other around the TME temperature. A new analytical approach for examining the slope of hardness-tempering temperature plots appear to reveal the TME phenomenon more sensitively. Dilatometric examinations substantiate that the temperature of hardness peak/inflection occurs beyond the second stage of tempering.

Ghosh, A.; Bhaduri, A.; Ray, K.K. (Indian Inst. of Tech., Kharagpur (India). Dept. of Metallurgical Engineering)

1994-12-01

198

Examination of carbon partitioning into austenite during tempering of bainite  

Energy Technology Data Exchange (ETDEWEB)

The redistribution of carbon after tempering of a novel nanocrystalline bainitic steel consisting of a mixture of supersaturated ferrite and retained austenite, has been analyzed by atom probe tomography. Direct supporting evidence of additional austenite carbon enrichment beyond that initially achieved during the bainite heat treatment was not obtained during subsequent tempering of this high carbon, high silicon steel. Evidence of competing reactions during tempering, such as the formation of carbon clusters in bainitic ferrite that signify the onset of the transitional carbides precipitation, was observed.

Clarke, Amy J [Los Alamos National Laboratory; Caballero, Francisca G [CENIM-CSIC, MADRIS, SPAIN; Miller, Michael K [ORNL; Garcia - Mateo, C [CENIM-CSIC, MADRID, SPAIN

2010-01-01

199

Determination of quenching and tempering conditions using hardenability prediction  

Energy Technology Data Exchange (ETDEWEB)

Experimental prediction of Jominy hardenability using Just`s equations often result in significant errors when compared to experimental data. In this paper, the development of an alternative Jominy predictor which provides excellent agreement with experimental data will be described. This new relationship can be written as: J(x) = Jo + F(x), where Jo is exclusively a function of the concentration of the alloying elements. This equation has been experimentally validated and a relationship with the tempering temperature was found: Tempering = F(Jo) The development of these equations and their successful application to the selection of quenching and tempering conditions in the heat treat shop will be discussed.

Oviedo, J. [CRAFMSA, San Luis (Argentina)

1996-12-31

200

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 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

2002-01-01

 
 
 
 
201

Heat treatment of structural steels for temper brittleness decrease  

International Nuclear Information System (INIS)

[en] Effect of heat treatment on embrittlement mechanism of steels 20, 12KhN3A, 14Kh2N3MA, 45 and 40Kh in temper brittleness has been studied. The steel tendency to temper brittleness is determined according to the shift of cold brittleness threshold during tests for impact bend in the temperature range from +100 to -190 deg C using quantitative stereofractography. It is established that the greatest shift of cold brittleness threshold (?T50) of steels 40Kh, 12KhN3A and 14Kh2N3MA takes place after quenching from 840-1100 deg C and tempering at 550 deg C (?T50=68, 48 and 44 deg C respectively), and for carbon steels 20 and 45 - after tempering at 525 deg C (?T50=28 deg C)

1983-01-01

202

Enhanced Sampling in the Well-Tempered Ensemble  

CERN Multimedia

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

203

Tempered random attractors for parabolic equations in weighted spaces  

Science.gov (United States)

This paper deals with the asymptotic behavior of solutions of parabolic equations on unbounded domains which contain stochastic terms as well as non-autonomous deterministic terms. We define a continuous random dynamical system for the equations in weighted Sobolev spaces that allow functions to have certain polynomial growth rate at infinity and hence include all bounded solutions. We prove pullback asymptotic compactness of solutions as well as the existence and uniqueness of tempered random attractors in the weighted spaces. The structures of the tempered attractors are fully characterized by tempered complete solutions. In the case where the non-autonomous deterministic terms are periodic in time, we show that the tempered random attractors are also periodic in time. To overcome the difficulty of non-compactness of Sobolev embeddings on unbounded domains, the idea of uniform pathwise estimates on the tails of solutions is employed to show asymptotic compactness.

Bates, Peter W.; Lu, Kening; Wang, Bixiang

2013-08-01

204

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

205

Tempering and Annealing in a Verdier-Stockmayer Polymer  

Directory of Open Access Journals (Sweden)

Full Text Available Two Monte Carlo methods, simulated annealing and parallel tempering, were applied to a Verdier-Stockmayer polymer. The efficiency of the two algorithms in exploring the lowest energy state possible for the model polymers was measured by the number of energy-degenerate configurations (configurations that have the same energy but are structurally different). Parallel tempering consistently explored more energy-degenerate configurations as compared with simulated annealing.

E. R. Obias; R. S. Banzon

2004-01-01

206

Method for heating, forming and tempering a glass sheet  

Energy Technology Data Exchange (ETDEWEB)

A method for heating, forming and tempering a glass sheet including the steps of heating at least one glass sheet to at least a first predetermined temperature, applying microwave energy to the glass sheet to heat the glass sheet to at least a second predetermined temperature, forming the glass sheet to a predetermined configuration, and cooling an outer surface of the glass sheet to at least a third predetermined temperature to temper the glass sheet.

Boaz, Premakaran Tucker (Livonia, MI); Sitzman, Gary W. (Walled Lake, MI)

1998-01-01

207

Prolonged residence of temperate natives in the tropics produces a suppression of sweating.  

UK PubMed Central (United Kingdom)

Tropical natives possess heat tolerance due to the ability to off-load endogenous and exogenous heat efficiently using a minimum amount of sweat. On the other hand, exposure of temperate natives to heat results in exaggerated production of sweat, of which part is lost by dripping and, thus, not available for evaporation. How sweating is modified in natives of temperate climate zones by prolonged residence in the tropics is not well-understood. The aim of this study was to investigate possible changes in the peripheral sweating mechanisms. Sweating responses to iontophoretically applied acetylcholine (ACh) were compared between Japanese subjects having either permanently resided in Japan (Japan resident Japanese, JRJ) or having stayed in the tropics for 2 years or longer (Tropics resident Japanese, TRJ). Quantitative sudomotor axon reflex tests by iontophoresis of ACh (10%, 2 mA for 5 min) were applied to determine directly activated (DIR) and axon reflex-mediated sweating during [AXR(1)] and after [AXR(2)] ACh iontophoresis. The sweat onset time of AXR(1) was 0.6 min shorter in JRJ than in TRJ (P<0.0001), and AXR(1) (P<0.0004), AXR(2) (P<0.0001), and DIR (P<0.0001) sweating responses were larger in JRJ than in TRJ. AXR and DIR sweating volumes (P<0.0001) were negatively correlated, and sweat onset times (P<0.0001) were positively correlated with the duration of residence in the tropics (2 to 13 years). The observed attenuation of sweating in TRJ suggests that temperate natives may acquire heat tolerance with improved sweating economy similar to tropical natives after prolonged residence in the tropics.

Bae JS; Lee JB; Matsumoto T; Othman T; Min YK; Yang HM

2006-10-01

208

Temperate grasslands as a dust source: Knowledge, uncertainties, and challenges  

Science.gov (United States)

Temperate grasslands are sensitive to climate change and are significant, or potentially significant, dust sources. Temperate grassland aeolian processes are unique in that the vegetation growth-decay cycle and weathering process due to extreme temperature changes profoundly affect the occurrence and intensity of wind erosion and dust emission. Human activities, such as animal husbandry or cultivation, also may result in land degradation and enhanced wind erosion. So far, little systematic research on temperate grassland wind erosion has been done, but this issue deserves particular attention. In this review paper, we summarize the understanding of temperate grassland wind-erosion processes and identify the uncertainties and research needs. The needs include (1) a deeper understanding of the aerodynamic and physical controls of grassland vegetation on wind erosion and dust emission processes, (2) scaling known relationships upwards to model the regional scale, (3) quantifying critical parameters affecting dust emissions (i.e., surface and aerodynamic roughness) via remote-sensing techniques, and (4) integrated wind-erosion modeling that incorporates grassland aeolian database and vegetation modeling of both seasonal growth and decay plus the impacts of grazing and cultivation. We also outline the research being carried out by Japanese scientists in collaboration with colleagues at Mongolian, American, and German research institutes in developing a temperate grassland wind-erosion modeling system, which can be used as a pre-warning system of severe dust storms and as a tool for strategic management of temperate grasslands.

Shinoda, M.; Gillies, J. A.; Mikami, M.; Shao, Y.

2011-12-01

209

Dung beetle communities: a neotropical-north temperate comparison.  

UK PubMed Central (United Kingdom)

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 neotropical 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.

Radtke MG; Fonseca CR; Williamson GB

2010-01-01

210

Dung beetle communities: a neotropical-north temperate comparison  

Scientific Electronic Library Online (English)

Full Text Available 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 neotropical 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 h (more) igher 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.

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

2010-02-01

211

Retained austenite and tempered martensite embrittlement in medium carbon steels  

Energy Technology Data Exchange (ETDEWEB)

Electron microscopy, diffraction and microanalysis, X-ray diffraction, and auger spectroscopy have been used to study quenched and quenched and tempered 0.3 pct carbon low alloy steels. Some in sit fracture studies were also carried out in a high voltage electron microscope. Tempered martensite embrittlement (TME) is shown to arise primarily as a microstructural constraint associated with decomposition of interlath retained austenite into M/sub 3/C films upon tempering in the range of 250/sup 0/C to 400/sup 0/C. In addition, intralath Widmanstatten Fe/sub 3/C forms from epsilon carbide. The fracture is transgranular with respect to prior austenite. The situation is analogous to that in upper bainite This TME failure is different from temper embrittlement (TE) which occurs at higher tempering temperatures (approximately 500/sup 0/C), and is not a microstructural effect but rather due to impurity segregation (principally sulfur in the present work) to prior austenite grain boundaries leading t intergranular fracture along those boundaries. Both failures can occur in the same steels, depending on the tempering conditions.

Sarikaya, M.; Jhingan, A.K.; Thomas, G.

1983-06-01

212

Retained austenite and tempered martensite embrittlement in medium carbon steels  

International Nuclear Information System (INIS)

[en] Electron microscopy, diffraction and microanalysis, X-ray diffraction, and auger spectroscopy have been used to study quenched and quenched and tempered 0.3 pct carbon low alloy steels. Some in sit fracture studies were also carried out in a high voltage electron microscope. Tempered martensite embrittlement (TME) is shown to arise primarily as a microstructural constraint associated with decomposition of interlath retained austenite into M3C films upon tempering in the range of 2500C to 4000C. In addition, intralath Widmanstatten Fe3C forms from epsilon carbide. The fracture is transgranular with respect to prior austenite. The situation is analogous to that in upper bainite This TME failure is different from temper embrittlement (TE) which occurs at higher tempering temperatures (approximately 5000C), and is not a microstructural effect but rather due to impurity segregation (principally sulfur in the present work) to prior austenite grain boundaries leading t intergranular fracture along those boundaries. Both failures can occur in the same steels, depending on the tempering conditions

1983-01-01

213

NON-TEMPER, TEXTURE PROVIDING FAT COMPOSITIONS  

UK PubMed Central (United Kingdom)

The present invention relates to a non-temper, texture providing fat composition comprising 10-65% by weight of one or more vegetable oils having a slip melting point of no more than 25 C and 35-90 % by weight of one or more vegetable fats having a slip melting point of more than 25 C wherein in said one or more vegetable fats at least 90% by weight of the constituent fatty acid chains are longer than C12, the ratio C16:0 / C18:0- C24:0 is no more than 4, and the ratio SSU / SUS is at least 1, and wherein in said composition the content of S3 -type of triglycerides is at least 0.5% by weight, wherein the groups S designates identical or different saturated fatty acids, and the groups U designates identical or different unsaturated fatty acids. The fat compositions provides texture at a similar or higher rate compared to state of the art fats at the same or a lower content of saturated fatty acids in confectionary applications. A method for the production of the fat compositions is described as well as some uses.

ANDERSEN MORTEN DAUGAARD; JUUL BJARNE

214

Large-scale processes and the Asian bias in species diversity of temperate plants.  

UK PubMed Central (United Kingdom)

An important issue in the study of biodiversity is the extent to which global patterns of species richness reflect large-scale processes and historical contingencies. Ecological interactions in local assemblages may constrain the number of species that can coexist, but differences in diversity in similar habitats within different regions (diversity anomalies) suggest that this limit is not firm. Variation in rate of species production could influence regional and perhaps local diversity independently of the ecological capacity of an area to support coexisting species, thereby creating diversity anomalies. Temperate Zone genera of plants that are disjunct between similar environments in eastern Asia and eastern North America (EAS-ENA) have twice as many species in Asia as in North America. Because lineages of these genera in Asia and North America are mostly sister pairs, they share a common history of adaptation and ecological relationship before disjunction. Thus, the diversity anomaly in EAS-ENA genera is not an artefact of taxon or habitat sampling but reflects differences in the net diversification (speciation-extinction) of the lineages in each of the continents. Here we propose that the most probable cause of the EAS-ENA anomaly in diversity is the extreme physiographical heterogeneity of temperate eastern Asia, especially compared with eastern North America, which in conjunction with climate and sea-level change has provided abundant opportunities for evolutionary radiation through allopatric speciation.

Qian H; Ricklefs RE

2000-09-01

215

Yields of minirotation closely spaced hardwoods in temperate regions: review and appraisal  

Energy Technology Data Exchange (ETDEWEB)

Published data are reviewed on the yields of ovendry stems and branches (S and B) with bark, and the mean annual increments (denoted MAISB) obtained fro 1 to 5-year old closely planted Platanus occidentalis, Populus spp., Ulmus parvifolia, and Alnus rubra, growing in north temperate regions. Data were discounted when the heights of sample trees inside experimental plots exceeded four times their distance from the edges of the plots. With the exception of 4 year yields of intensively cultured poplars in Wisconsin, all published yield data fell close to, or below, the response surface described empirically by the equation the square root of t/ha equals 1.19 plus 1.46 (age in years) plus 0.328 (log 1,000 tree/hectare). The ''working maximum'' MAISB of 4 to 5 year old minirotations forests in much of the temperate zone seems to be 10-12 ton/hectare/year, no greater than the MAISB of some Populus plantations grown over rotations of 11-26 years. However, 10-30 percent greater yields have been recorded at ages 1-5 following coppicing, and MAISB values probably continue to increase after age 5.

Cannell, M.G.R.; Smith, R.I.

1980-09-01

216

Genetic Structure of Setosphaeria turcica Populations in Tropical and Temperate Climates.  

UK PubMed Central (United Kingdom)

ABSTRACT Northern leaf blight, caused by Setosphaeria turcica, is a serious disease of maize in temperate and tropical environments. To examine the pathogen's population structure, we analyzed 264 isolates from four different continents with 70 random amplified polymorphic DNA markers and determined their mating types. Tropical populations (from Kenya, Mexico, and southern China) had an extremely high genotypic diversity, no or only weak gametic phase disequilibrium, and an even distribution of the two mating types, indicating frequent sexual recombination. Temperate populations (from Europe and northern China) had a much lower genotypic diversity, strong gametic phase disequilibrium, and an uneven distribution of mating types, indicating that sexual recombination has been rare. Populations in different continents were genetically isolated. They shared no haplotypes and carried several "private" alleles. The number of migrants between continents and between regions (between northern and southern China, western and central Kenya, and Europe west and east of the Alps) was estimated to be less than one per generation. Multivariate statistics suggested a greater relatedness of populations from the same continents than from different continents. Within agroecological zones, migration must be extensive. The potential within populations of S. turcica for adaptation should be regarded as very high, especially in tropical climates.

Borchardt DS; Welz HG; Geiger HH

1998-04-01

217

Genetic Structure of Setosphaeria turcica Populations in Tropical and Temperate Climates.  

Science.gov (United States)

ABSTRACT Northern leaf blight, caused by Setosphaeria turcica, is a serious disease of maize in temperate and tropical environments. To examine the pathogen's population structure, we analyzed 264 isolates from four different continents with 70 random amplified polymorphic DNA markers and determined their mating types. Tropical populations (from Kenya, Mexico, and southern China) had an extremely high genotypic diversity, no or only weak gametic phase disequilibrium, and an even distribution of the two mating types, indicating frequent sexual recombination. Temperate populations (from Europe and northern China) had a much lower genotypic diversity, strong gametic phase disequilibrium, and an uneven distribution of mating types, indicating that sexual recombination has been rare. Populations in different continents were genetically isolated. They shared no haplotypes and carried several "private" alleles. The number of migrants between continents and between regions (between northern and southern China, western and central Kenya, and Europe west and east of the Alps) was estimated to be less than one per generation. Multivariate statistics suggested a greater relatedness of populations from the same continents than from different continents. Within agroecological zones, migration must be extensive. The potential within populations of S. turcica for adaptation should be regarded as very high, especially in tropical climates. PMID:18944955

Borchardt, D S; Welz, H G; Geiger, H H

1998-04-01

218

A phylogenetic perspective on the individual species-area relationship in temperate and tropical tree communities.  

UK PubMed Central (United Kingdom)

Ecologists have historically used species-area relationships (SARs) as a tool to understand the spatial distribution of species. Recent work has extended SARs to focus on individual-level distributions to generate individual species area relationships (ISARs). The ISAR approach quantifies whether individuals of a species tend have more or less species richness surrounding them than expected by chance. By identifying richness 'accumulators' and 'repellers', respectively, the ISAR approach has been used to infer the relative importance of abiotic and biotic interactions and neutrality. A clear limitation of the SAR and ISAR approaches is that all species are treated as evolutionarily independent and that a large amount of work has now shown that local tree neighborhoods exhibit non-random phylogenetic structure given the species richness. Here, we use nine tropical and temperate forest dynamics plots to ask: (i) do ISARs change predictably across latitude?; (ii) is the phylogenetic diversity in the neighborhood of species accumulators and repellers higher or lower than that expected given the observed species richness?; and (iii) do species accumulators, repellers distributed non-randomly on the community phylogenetic tree? The results indicate no clear trend in ISARs from the temperate zone to the tropics and that the phylogenetic diversity surrounding the individuals of species is generally only non-random on very local scales. Interestingly the distribution of species accumulators and repellers was non-random on the community phylogenies suggesting the presence of phylogenetic signal in the ISAR across latitude.

Yang J; Swenson NG; Cao M; Chuyong GB; Ewango CE; Howe R; Kenfack D; Thomas D; Wolf A; Lin L

2013-01-01

219

Back to the French gas winter  

International Nuclear Information System (INIS)

[en] Contradictory to the 2004-2005 winter and thanks to a careful management, gas operators could cope in 2006 with winter hazards. Despite an important cold wave, which started in Russia and then moved to Europe, and some Russian-Ukrainian tensions, no erasable contract has been stopped during the winter of 2006. Finally, the tensions on the UK market prices have not been transmitted to the continent. (J.S.)

2006-01-01

220

The cycling of readily available phosphorus in response to elevated phosphate in acidic temperate deciduous forests  

UK PubMed Central (United Kingdom)

The biogeochemical cycling of phosphorus (P) in temperate forest ecosystems is poorly understood relative to nitrogen (N) cycling because of the assumption that N is the main factor that limits plant growth. This dichotomous way of understanding nutrient regimes is likely an oversimplification of these dynamic, interacting cycles within the evermore-dynamic framework of soil development. In order to better understand P cycling in temperate deciduous forests, we sought to quantify labile (resin) P flux and determine if soil shows signs of P stress. Labile P flux was quantified in nine ambient and nine elevated P plots on unglaciated eastern deciduous forests in Eastern Ohio. Anion exchange membranes (AEMs) were deployed in situ for two weeks, in the fall and the winter. Flux values were contextualized by resin P pools, N and P mineralization, and phosphatase enzyme activities determined from soil samples collected both at the time of AEM deployment and harvest. Phosphorus flux was 0.64±0.23?gPd?¹ (mean±SD) in ambient plots and 3.47±2.39?gPd?¹ in amended P plots. Resin P pools were 4.16mgkg?¹ and 10.26mgkg?¹ in the control and elevated plots, respectively. Phosphorus turnover rate increased from one week in control plots, to 3 days in elevated P plots. Results indicate mild P stress relative to N, as N was mineralized (0.84±0.18mgNkg?¹d?¹) while P was immobilized (?0.22±0.09mgPkg?¹d?¹). The elevated P treatment did not increase P mineralization. Phosphatase enzyme activities were significantly suppressed by 34% with P amendment. Results suggest labile P is a shallow pool, but is rapidly cycling.

Shaw AlannaN; DeForest JaredL

2013-01-01

 
 
 
 
221

Development of microsatellites in Machilus thunbergii (Lauraceae), a warm-temperate coastal tree species in Japan.  

UK PubMed Central (United Kingdom)

PREMISE OF THE STUDY: Microsatellite markers were developed and characterized in a typically coastal, widespread, and dominant tree species of the evergreen broadleaf forests, Machilus thunbergii, for comparison of the genetic diversity and structure of inland populations surrounding the ancient Lake Biwa and coastal populations in Japan. METHODS AND RESULTS: Eighteen polymorphic microsatellites of this species were isolated using an improved technique for isolating codominant compound microsatellite markers. These isolated loci provided compound simple sequence repeat (SSR) markers with polymorphisms of three to 19 alleles per locus, with an average of 10.9. The expected and observed within-population heterozygosities ranged from 0.16 to 0.86 and from 0.13 to 0.72, respectively. CONCLUSIONS: These markers may be useful tools for further investigation of the population genetic structure and biogeographic history of M. thunbergii in the warm-temperate zone of East Asia.

Kaneko Y; Lian C; Watanabe S; Shimatani K; Sakio H; Noma N

2012-07-01

222

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

UK PubMed Central (United Kingdom)

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 content of juvenile roach (Rutilus rutilus) was affected by the physiologically relatively small (2-5 °C) changes of winter temperatures predicted by the Intergovernmental Panel on Climate Change (IPCC), under both natural and experimental conditions. This was investigated in combination with the effects of food availability. Finally, we explored the potential for a correlation between lake temperature and resource levels for planktivorous fish, i.e., zooplankton biomass, during five consecutive winters in a south Swedish lake. We show that small increases in temperature (+2 °C) affected fish biomass loss in both presence and absence of food, but negatively and positively respectively. Temperature alone explained only a minor part of the variation when food availability was not taken into account. In contrast to other studies, lipid analyses of experimental fish suggest that critical somatic condition rather than critical lipid content determined starvation induced mortality. Our results illustrate the importance of considering not only changes in temperature when predicting organism response to climate change but also food-web interactions, such as resource availability and predation. However, as exemplified by our finding that zooplankton over-winter biomass in the lake was not related to over-winter temperature, this may not be a straightforward task.

Brodersen J; Rodriguez-Gil JL; Jönsson M; Hansson LA; Brönmark C; Nilsson PA; Nicolle A; Berglund O

2011-01-01

223

Cage evaluation of augmentative biological control of Thrips palmi with Wollastoniella rotunda in winter greenhouses.  

UK PubMed Central (United Kingdom)

Cage trials of an anthocorid predator, Wollastoniella rotunda Yasunaga et Miyamoto, as a biological control agent of Thrips palmi Karny were conducted in Fukuoka, Japan, under winter greenhouse production conditions. Females of W. rotunda were released on caged eggplants, and placed in two greenhouses on 27 October. The development, population growth, and effectiveness of W. rotunda were observed until early March. Results from the cage trials showed that W. rotunda successfully developed, reproduced, and suppressed T. palmi populations under the conditions found in winter greenhouses. During the experiment, one full generation and a second generation of adult predators occurred. The T. palmi population which was exposed to predators remained at a low density throughout the trial period, but it increased dramatically on eggplants without W. rotunda. The maximum difference between predator treatments and controls was approximately 10-fold by the end of January. Wollastoniella rotunda has the potential to be an effective control agent for T. palmi on eggplant, even during the winter in temperate regions.

Nakashima Y; Uefune M; Tagashira E; Maeda S; Shima K; Nagai K; Hirose Y; Takagi M

2004-01-01

224

Winter Olympics Physics and Biomechanics  

Science.gov (United States)

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

225

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

2013-01-01

226

Effect of cohesive energy on thermal expansion behavior of T6 tempered 7A09 aluminum alloy  

Energy Technology Data Exchange (ETDEWEB)

Highlights: Black-Right-Pointing-Pointer Transformation related to {eta}' and {eta} can cause cohesive energy and volume changes. Black-Right-Pointing-Pointer These changes can influence the variation trend of CTE for 7A09 alloy. Black-Right-Pointing-Pointer Cohesive energy change becomes a main factor influencing CTE from Ostwald ripening stage. - Abstract: The dynamic effect of cohesive energy on the CTE of T6 (the highest strength temper) tempered 7A09 aluminum alloy was studied in this paper. Transmission electron microscopy (TEM) was combined with differential scanning calorimetry (DSC) to analyze the phase transitions of T6 tempered 7A09 aluminum alloy taking place in a heating process. The corresponding CTE curve was recorded by a thermal dilatometer. The ion-bonding model was utilized to estimate the variation of cohesive energy caused by the phase transitions. Results indicate that GPII zones and {eta} Prime phase are main precipitates in T6 tempered 7A09 alloy. During the heating process, the cohesive energy of alloy system increases with the transition from {eta} Prime to {eta} phase and the precipitation of {eta} phase. The dissolution of {eta} phase leads to a decrease of cohesive energy. Although volume changes of alloy system have effects on the CTE, the effect of the cohesive energy change is more obvious than that of volume change after the precipitation of {eta} phase begins in the Ostwald ripening stage. Effects of cohesive energy and volume changes can be expressed in the nonlinearity of CTE curve.

Yuan Lin; Ji Hongzhi [School of Materials Science and Engineering, Harbin Institute of Technology, Harbin 150001 (China); Shan Debin, E-mail: shandb@hit.edu.cn [School of Materials Science and Engineering, Harbin Institute of Technology, Harbin 150001 (China)

2012-02-05

227

Interim Report 'Winter smog and traffic'.  

Digital Repository Infrastructure Vision for European Research (DRIVER)

This report presents a halfway score of the research project "Winter smog and Traffic", one of the themes of the research programme "Air Pollution and Health". A state of the art is presented of the health effects associated with exposure to winter smog and of the toxicological effects caused by the...

Bloemen, H.; Blom, T.; Bogaard, C., van den; Boluyt, N.; Bree, L., van; Brunekreef, B.; Hoek, G.; Zee, S., van der

228

PLCO News, Fall/Winter 1998  

Science.gov (United States)

PLCO News, Fall/Winter 1998 Volume 1, Number 2 ----- Fall/Winter 1998 Trial Update Enrollment goal: 148,000 Total enrollment (as of September 30, 1998): 111,515 Men enrolled: 58,283 Women enrolled: 53,232 Number of people enrolled

229

Resistance to small plastic strains during martensite tempering under tension  

Energy Technology Data Exchange (ETDEWEB)

The mechanism of plastic deformation of martensite of a series of hardened steels (N18, 20KhG, 50KhFA and others) during tempering under tension and the role of residual internal microstresses and phase transformations are studied. It is shown that martensite low resistance to small plastic deformations during tempering under tension which is usually associated with phase transformations depends as well on the level of residual internal microstresses in the martensite structure. The decrease of resistance to deformation in the course of the decomposition of a solid solution is due to weakening of martensitic matrix because of carbon departure from the solid solution and carbide coarsening. An assumption is made that martensite plastic deformation during tempering under tension is realized at the expense of the directed microplastic deformation in the regions of higher concentration of internal stresses.

Zabil' skij, V.V.; Sarrak, V.I. (AN SSSR, Sverdlovsk. Inst. Fiziki Metallov)

1982-11-01

230

Resistance to small plastic strains during martensite tempering under tension  

International Nuclear Information System (INIS)

The mechanism of plastic deformation of martensite of a series of hardened steels (N18, 20KhG, 50KhFA and others) during tempering under tension and the role of residual internal microstresses and phase transformations are studied. It is shown that martensite low resistance to small plastic deformations during tempering under tension which is usually associated with phase transformations depends as well on the level of residual internal microstresses in the martensite structure. The decrease of resistance to deformation in the course of the decomposition of a solid solution is due to weakening of martensitic matrix because of carbon departure from the solid solution and carbide coarsening. An assumption is made that martensite plastic deformation during tempering under tension is realized at the expense of the directed microplastic deformation in the regions of higher concentration of internal stresses

1982-01-01

231

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; Moon-Soo Park; Gyung Soon Kim; Chang Seok Lee

2011-01-01

232

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.

2005-05-11

233

Redistribution of alloying elements during tempering of a nanocrystalline steel  

International Nuclear Information System (INIS)

Redistribution of alloying elements during tempering of a novel nanocrystalline steel consisting of a mixture of lower bainitic ferrite and carbon-enriched retained austenite has been analyzed by atom probe tomography. Three physical processes, namely redistribution of substitutional solute across the austenite/bainitic ferrite interface before retained austenite decomposition, redistribution of solute across the lower bainite cementite/ferrite interface, and the precipitation of transition carbides and cementite, have been observed. Results suggest that retained austenite decomposes during tempering before full equilibrium is reached at the interface. Moreover, cementite precipitates from supersaturated ferrite via a paraequilibrium transformation mechanism.

2008-01-01

234

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

Digital Repository Infrastructure Vision for European Research (DRIVER)

The present study describes a Late Miocene (early Tortonian - early Messinian) transitional carbonate system that combines elements of tropical and cool-water carbonate systems (Irakleion Basin, island of Crete, Greece). As documented by stratal geometries, the submarine topography of the basin was ...

Reuter, Markus

235

Production of Chlorella biomass in different types of flat bioreactors in temperate zones  

Energy Technology Data Exchange (ETDEWEB)

The influence of several variables on the growth rate of the green algae Chlorella pyrenoidosa Chick has been studied. The effects of changes in culture medium, temperature and light are reported. For the production of algae biomass, three different types of closed-culture systems or bioreactors were used (flexible sheath, translucent tubes and rigid panels, all of them in PVC) under different environmental conditions (chamber, greenhouse and outdoor culture). The results show that the growth of Chlorella is influenced by water quality. However, the algae have a good resistance to temperature variations and they can grow even under low light intensity conditions. Comparing the performance of different bioreactors, it was shown that the outdoor rigid panel system with integrated temperature regulation resulted in a biomass production similar to that for cultures grown in outdoor open ponds in regions with better climatic conditions. 15 references.

Ramos de Ortega, A.; Roux, J.C.

1986-01-01

236

SIMULATED CLIMATE CHANGE EFFECTS ON YEAR-ROUND WATER TEMPERATURES IN TEMPERATE ZONE LAKES. (R824801)  

Science.gov (United States)

The perspectives, information and conclusions conveyed in research project abstracts, progress reports, final reports, journal abstracts and journal publications convey the viewpoints of the principal investigator and may not represent the views and policies of ORD and EPA. Concl...

237

Scientifically-founded measurement for winter cold load on structure parts and their mapping of the Federal Republic of Germany  

Energy Technology Data Exchange (ETDEWEB)

For the recent new edition of DIN 18910 it became necessary to redraw the German climate zone maps. Mean annual temperature minima were recognized as being an adequate expression of the severity of winter cold. The data prepared by Reidat for the building industry are more adequate for correctly judging the cold load on structural walls. Since Reidat's very detailed data were based on readings from a very few weather stations, it was necessary to search for weather data from a much wider range of localities which would correlate closely with Reidat's figures. Having found such an index in the 'winter ice day' (WID) concept, it became possible to map Germany sufficiently well in this respect. In this way a totally new and more highly differentiated map of winter temperature zones was developed.

Schreiber, D.

1982-07-01

238

Activity of the mangrove snail Cerithidea decollata (Gastropoda: Potamididae) in a warm temperate South African estuary  

Science.gov (United States)

A population of Cerithidea decollata, an intertidal marine gastropod usually found within mangroves, was studied within an area of Juncus kraussii in the upper reaches of the warm temperate Knysna estuary, which is at the southern-most limit of the recorded distribution of this snail. Activity (migratory and homing behaviour, distances travelled during foraging) of the snails was monitored over spring and neap tides in four seasons. Migratory patterns of the snails were affected by season, time of low tide (day vs night), tidal magnitude (spring vs neap) and zonation. In the summer and spring, a greater proportion of snails migrated from J. kraussii leaves onto the mud during the day at spring low tide. During neap tides in these two seasons, most snails did not climb J. kraussii leaves and remained on the mud, which was nearly always exposed. In autumn a few snails only were active and in winter snails were almost completely inactive, probably due to low air temperatures. Snails travelled greater distances on the mud on spring tides, during the diurnal low tides, and in the summer. No snails were found to home to individual J. kraussii leaves; however, homing behaviour was recorded to wooden poles within the Juncus wetland.

Hodgson, Alan N.; Dickens, John

2012-08-01

239

Seasonal dynamics of fungal communities in a temperate oak forest soil.  

UK PubMed Central (United Kingdom)

Fungi are the agents primarily responsible for the transformation of plant-derived carbon in terrestrial ecosystems. However, little is known of their responses to the seasonal changes in resource availability in deciduous forests, including photosynthate allocation below ground and seasonal inputs of fresh litter. Vertical stratification of and seasonal changes in fungal abundance, activity and community composition were investigated in the litter, organic and upper mineral soils of a temperate Quercus petraea forest using ergosterol and extracellular enzyme assays and amplicon 454-pyrosequencing of the rDNA-ITS region. Fungal activity, biomass and diversity decreased substantially with soil depth. The highest enzyme activities were detected in winter, especially in litter, where these activities were followed by a peak in fungal biomass during spring. The litter community exhibited more profound seasonal changes than did the community in the deeper horizons. In the litter, saprotrophic genera reached their seasonal maxima in autumn, but summer typically saw the highest abundance of ectomycorrhizal taxa. Although the composition of the litter community changes over the course of the year, the mineral soil shows changes in biomass. The fungal community is affected by season. Litter decomposition and phytosynthate allocation represent important factors contributing to the observed variations.

Vo?íšková J; Brabcová V; Cajthaml T; Baldrian P

2013-09-01

240

Experimental evaluation of thermal and energy performance of temperate green roofs: a case study in Beijing  

Science.gov (United States)

An experimental evaluation of thermal and energy performance of temperate green roofs was carried out by thermal and meteorological observation and energy budget modeling using a setup of green roof in Beijing urban area. From both the yearly and daily temperature trends, the green roof could effectively damp down the undulation of roof surface temperature comparing with the conventional one. As an insulating screen, the green roof abated the amplitude of temperature by 9.0 in winter and 9.1 °C in summer, respectively. Under different cloud conditions, the green roof in summer time resulted in decreases in sensible heat and heat flux by 125.3W m-2 and 32.0 W m-2, respectively, on daily average comparing with the conventional one. Based on the energy budget analyses, under an assumptive scenario of 50% roof-greening in Beijing, a total of 34.1 PJ of sensible heat and 8.7 PJ of heat flux would be decreased for a summer period of 90 days. This study demonstrated that green roof, serving as an insulating screen to building top in comparison with the conventional roof, proved thermal improving effect in building scale and high energy saving potential for urban development.

Sun, T.; Institute of Hydrology; Water Resources

2011-12-01

 
 
 
 
241

Influence of the tempering activated water and modifying agents on the durability of foamed concretes / ??????? ?????????????? ???? ?????????? ? ?????????????? ??????? ?? ????????? ???????? ???????  

Directory of Open Access Journals (Sweden)

Full Text Available The description of the model of the new method of the tempering water activation of tempering for cement grouts and concretes is given. The influence of the tempering activated water, modifying agents and fibrils on the durability of foamed concretes is stated. / ???? ???????? ?????? ?????? ?????? ????????? ???? ?????????? ??? ????????? ??????-??? ? ???????. ??????????? ??????? ?????????????? ???? ??????????, ?????????????? ??-????? ? ???????? ??????? ?? ????????? ???????? ???????.

Kotlyarevskaya A.V. / ???????????? ????? ??????????; Volskaya O.N. / ???????? ????? ??????????; Perfilov V.A. / ???????? ???????? ?????????????; Kusmartseva O.A. / ?????????? ????? ?????????????

2011-01-01

242

Root Apex Transition Zone As Oscillatory Zone.  

UK PubMed Central (United Kingdom)

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.

Baluška F; Mancuso S

2013-01-01

243

Stable isotope evidence of diverse species-specific and individual wintering strategies in seabirds.  

UK PubMed Central (United Kingdom)

Although there is increasing evidence that climatic variations during the non-breeding season shape population dynamics of seabirds, most aspects of their winter distribution and ecology remain essentially unknown. We used stable isotope signatures in feathers to infer and compare the moulting (wintering) habitat of subantarctic petrels breeding at two distant localities (South Georgia and Kerguelen). Petrels showed species-specific wintering habitat preferences, with a similar pattern of latitudinal segregation for all but one taxon. At both localities, delta13C values indicated that blue petrels (Halobaena caerulea) moult in Antarctic waters, South Georgian diving petrels (Pelecanoides georgicus) in the vicinity of the archipelagos and/or in the Polar Frontal Zone and Antarctic prions (Pachyptila desolata) in warmer waters. In contrast, common diving petrels (Pelecanoides urinatrix) showed divergent strategies, with low and high intrapopulation variation at South Georgia and Kerguelen, respectively. Birds from Kerguelen dispersed over a much wider range of habitats, from coastal to oceanic waters and from Antarctica to the subtropics, whereas those from South Georgia wintered mainly in waters around the archipelago. This study is the first to show such striking between-population heterogeneity in individual wintering strategies, which could have important implications for likely demographic responses to environmental perturbation.

Cherel Y; Phillips RA; Hobson KA; McGill R

2006-06-01

244

SUGARCANE POST-HARVEST RESIDUE MANAGEMENT IN TEMPERATE CLIMATES  

Science.gov (United States)

Retention of post-harvest residue can decrease cane yield by 4.5-13.5 t/ha in the temperate climate of Louisiana. A series of experiments was conducted to determine the physiological causes for this loss and to develop management practices to mitigate the effects of residue retention. Chemical ext...

245

Antarctic, Sub-Antarctic and cold temperate echinoid database  

Digital Repository Infrastructure Vision for European Research (DRIVER)

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°...

Benjamin Pierrat; Thomas Saucède; Alain Festeau; Bruno David

246

Antarctic, Sub-Antarctic and cold temperate echinoid database  

Digital Repository Infrastructure Vision for European Research (DRIVER)

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°...

Pierrat, Benjamin; Saucède, Thomas; Festeau, Alain; David, Bruno

247

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.

2000-01-01

248

Temperate Bacteriophage Infectious for Asporogenic Variants of Bacillus pumilus  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Bacillus pumilus strain NRRL B-3275 is lysogenic for an inducible, nondefective temperate bacteriophage ?75. ?75 infects and lysogenizes several asporogenic mutants of B. pumilus strain NRS 576 but does not productively infect the spore+ parent. ?75 DNA is a linear duplex with a mol wt of about 29 ×...

Bramucci, Michael G.; Lovett, Paul S.

249

RELATIONSHIP BETWEEN INTERNAL FRICTION AND TEMPER BRITTLENESS OF ALLOY STEELS  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Impact tests and internal friction measurements were carried out for steels 40Mn2, 40Mn2Mo and 30CrMnSiNi2. Experimental results showed that the phenomenon of temper brittleness is related to the aging effect of ? - solid solution in steels with precipitation of Fe3 (C, N) particles causing dead-pin...

Tang, Chih-Hsiou; Su, Mei; Lei, Ting-Chuan

250

Species diversity of Lachnum (Helotiales, Hyaloscyphaceae) from temperate China*  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Twenty-three temperate China species of Lachnum, Lachnum abnorme, L. angustum, L. brevipilosum, L. calosporum, L. calyculiforme, L. carneolum, L. ciliare, L. controversum, L. flavidulum, L. cf. fushanese, L. indicum, L. kumaonicum, L. lushanese, L. minutum, L. montanum, L. cf. pteridophyllum, L. pyg...

Ye, Ming; Cao, Shu-qing; Jiang, Shao-tong; Pan, Li-jun; Luo, Shui-zhong; Li, Xing-jiang

251

ACUTE FOLIC ACID DEFICIENCY OF UNKNOWN AETIOLOGY: TEMPERATE SPRUE.  

UK PubMed Central (United Kingdom)

The 20 patients described could be included in the group of patients diagnosed as ;idiopathic steatorrhoea'. However, their histories were short and diarrhoea was not a major feature. Since megaloblastic anaemia due to folic acid deficiency was a common feature it is suggested that these patients may form a homogeneous group and the diagnostic label of temperate sprue is suggested.

COOKE WT; FONE DJ; COX EV; MEYNELL MJ; GADDIE R

1963-09-01

252

Mesoscale Precipitation Systems in Winter Storms.  

Science.gov (United States)

Heavy frozen precipitation produced by complex mesoscale patterns embedded within winter extratropical cyclones (ETCs) adversely affect many areas of the United States each year. The initiation, organization, and movement of these mesoscale precipitation ...

M. A. Kaster

1993-01-01

253

Earth-Sun Geometry: Winter Solstice Animation  

Science.gov (United States)

The representation depicts the position of the Earth relative to the Sun during the southern hemisphere's winter solstice and includes line of latitude and the angle of the Sun's rays at the Tropic of Capricorn.

Pidwirny, Michael; Okanagan, Scott J.

254

[The skin, cold and winter sports  

UK PubMed Central (United Kingdom)

Winter sports are responsible for various dermatoses which could be often avoided by simple preventive procedures. Both the severity and duration of cold exposure combined with wind speed, altitude and environmental hygrometric value govern the potential types of cold injuries.

Claes G; Henry F; Letawe C; Piérard GE

2001-04-01

255

Overview of climatic effects of nuclear winter  

International Nuclear Information System (INIS)

A general description of the climatic effects of a nuclear war are presented. This paper offers a short history of the subject, a discussion of relevant parameters and physical processes, and a description of plausible nuclear winter scenario. 9 refs

1985-01-01

256

The Exxon Valdez winter monitoring program results  

International Nuclear Information System (INIS)

[en] This paper reports that Eighteen stations in Prince William Sound have been monitored on a monthly basis as part of the winter studies program developed by NOAA for scientific support at the Exxon Valdez oil spill. The objectives of the winter monitoring program were to: determine the persistence of oil at stations representative of the various shoreline types, degrees of exposure, extent of oiling, and treatment received during the summer of 1989; track the winter storm activity through the deployment of meteorological stations in the Sound; monitor the beach morphology changes and correlate them with winter storm intensity; quantify the oil changes at the stations and estimate the amount of oil remaining on the shoreline as of spring 1990; and characterize the weathering trends in chemical composition of the residual oil in both surface and subsurface sediments, for determination of treatability requirements and toxicity/bioavailability of oil remaining on the shoreline in 1990

1990-01-01

257

VESTA Viticulture Course: Winter Viticulture Technology  

Science.gov (United States)

This site, from the Viticulture and Enology Science and Technology Alliance, offers presentations and slides from the lectures of VIN 113: Winter Viticulture Technology. From the presenter, Katie Gill, the lectures cover such topics as pruning and winter grapevine anatomy. Each topic includes a multimedia presentation of the lecture, with slides. Users must have Microsoft's Silverlight installed to view the presentations, which vary in length from about 2 minutes to 7 minutes.

2010-10-27

258

Morphofunctional state of the adrenal glands in albino rats under conditions of toxic stress caused by cadmium salt in winter and summer periods.  

Science.gov (United States)

We studied the morphology and function of the adrenal glands in male and female albino rats in cadmium intoxication during winter and summer periods (January and July). In animals of the control group, sex-related differences in the total area of the adrenal glands and in the size of their zones were revealed. In females, zones of adrenal gland were larger than in males. In winter months, these differences were most pronounced. Analysis of seasonal differences in the area of the adrenal glands in males revealed no significant differences in winter and summer months. Irrespective of the season and gender, cadmium chloride treatment led to an increase in the size of the adrenal glands. Cadmium salts caused more pronounced functional strain in males in winter months and in females in summer. PMID:22238762

Kotelnikova, S V; Kargina, M V; Kotelnikov, A V

2011-06-01

259

Morphofunctional state of the adrenal glands in albino rats under conditions of toxic stress caused by cadmium salt in winter and summer periods.  

UK PubMed Central (United Kingdom)

We studied the morphology and function of the adrenal glands in male and female albino rats in cadmium intoxication during winter and summer periods (January and July). In animals of the control group, sex-related differences in the total area of the adrenal glands and in the size of their zones were revealed. In females, zones of adrenal gland were larger than in males. In winter months, these differences were most pronounced. Analysis of seasonal differences in the area of the adrenal glands in males revealed no significant differences in winter and summer months. Irrespective of the season and gender, cadmium chloride treatment led to an increase in the size of the adrenal glands. Cadmium salts caused more pronounced functional strain in males in winter months and in females in summer.

Kotelnikova SV; Kargina MV; Kotelnikov AV

2011-06-01

260

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

2013-10-01

 
 
 
 
261

Neopaleozoic flora in stratigraphic zones of Gondwana  

Energy Technology Data Exchange (ETDEWEB)

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

Archangelsky, S.

1984-01-01

262

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

Directory of Open Access Journals (Sweden)

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; G. Jurasinski; S. Glatzel

2012-01-01

263

Vadose zone microbiology  

Energy Technology Data Exchange (ETDEWEB)

The vadose zone is defined as the portion of the terrestrial subsurface that extends from the land surface downward to the water table. As such, it comprises the surface soil (the rooting zone), the underlying subsoil, and the capillary fringe that directly overlies the water table. The unsaturated zone between the rooting zone and the capillary fringe is termed the "intermediate zone" (Chapelle, 1993). The vadose zone has also been defined as the unsaturated zone, since the sediment pores and/or rock fractures are generally not completely water filled, but instead contain both water and air. The latter characteristic results in the term "zone of aeration" to describe the vadose zone. The terms "vadose zone," "unsaturated zone", and "zone of aeration" are nearly synonymous, except that the vadose zone may contain regions of perched water that are actually saturated. The term "subsoil" has also been used for studies of shallow areas of the subsurface immediately below the rooting zone. This review focuses almost exclusively on the unsaturated region beneath the soil layer since there is already an extensive body of literature on surface soil microbial communities and process, e.g., Paul and Clark (1989), Metting (1993), Richter and Markowitz, (1995), and Sylvia et al. (1998); whereas the deeper strata of the unsaturated zone have only recently come under scrutiny for their microbiological properties.

Kieft, Thomas L.; Brockman, Fred J.

2001-01-17

264

Soil moisture dynamics modeling considering multi-layer root zone.  

UK PubMed Central (United Kingdom)

The moisture uptake by plant from soil is a key process for plant growth and movement of water in the soil-plant system. A non-linear root water uptake (RWU) model was developed for a multi-layer crop root zone. The model comprised two parts: (1) model formulation and (2) moisture flow prediction. The developed model was tested for its efficiency in predicting moisture depletion in a non-uniform root zone. A field experiment on wheat (Triticum aestivum) was conducted in the sub-temperate sub-humid agro-climate of Solan, Himachal Pradesh, India. Model-predicted soil moisture parameters, i.e., moisture status at various depths, moisture depletion and soil moisture profile in the root zone, are in good agreement with experiment results. The results of simulation emphasize the utility of the RWU model across different agro-climatic regions. The model can be used for sound irrigation management especially in water-scarce humid, temperate, arid and semi-arid regions and can also be integrated with a water transport equation to predict the solute uptake by plant biomass.

Kumar R; Shankar V; Jat MK

2013-01-01

265

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

UK PubMed Central (United Kingdom)

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.

Jones HG; Hillis RM; Gordon SL; Brennan RM

2013-01-01

266

Importance of winter cereals with winter pea mixtures on family farms in Croatia  

Directory of Open Access Journals (Sweden)

Full Text Available The object of this research was to ensure quality green forage and silage early in the spring on family farms in northern Croatia, through introducing winter cereals and Winter pea mixtures. For that purpose mixtures of Winter pea (cv. Maksimirski visoki) with triticale (cv. Clercal) were cut in the beginning of May, while the mixtures of Winter pea with wheat (cv. Sana and cv. Žitarka) were cut in the second half of May at family farms: Maleti? (Ferdinandovac), Mirovi? (Višnjevac), Bazi? (M. Trojstvo), Mlinar (Kapela Podravska), Mužini? (Križev?ec) i Uher (Grabovac). The mixtures were used to feed dairy cows from the beginning of flowering till the full bloom of Winterpea. The green mass yields (GMY) for mixtures of Winter pea with triticale cut in the beginning of pea flowering varied from 24.0 to 52.7 t/ha, while the GMY of mixtures cut in the full bloom of Winter pea were from 46.7 to 67.5 t/ha. Average dry matter yields (DMY) for mixtures of Winter pea with triticale cut in the beginning of flowering varied from 4.05 to 12.2 t/ha, while the DMY of mixtures cut in the full bloom of Winter pea were from 8.98 to 18.39 t/ha. All mixtures of Winter pea with triticale cut in the beginning of flowering had drymatter content (DMC) from 19.41 % while the DMC of mixtures cut in the full bloom of Winter pea were from 23.56 %. The GMY for mixtures of Winter pea with wheat cut in the beginning of pea flowering varied from 23.2 to 50.0 t/ha, while the GMY of mixtures cut in the full bloom of Winter pea were from 53.3 to 62.5 t/ha. The DMY for mixtures of Winter pea with wheat cut in the beginning of flowering varied from 4.39 to 9.49 t/ha, while the DMY of the same mixture cut in the full bloom were from 10.67 to 15.59 t/ha. All mixtures of Winter pea with wheat cut in the beginning of flowering had DMC from 17.0 % to 20.96 %, while the DMC of the same mixtures cut in the full bloom were from 20.00 % to 27.31 %.

Zvonimir Štafa; Darko Uher; Dubravko Ma?eši?; Dubravko Ma?eši?; Gordana Mužini?

2002-01-01

267

Effect of tempering on corrosion resistance of cast aluminium bronzes  

International Nuclear Information System (INIS)

[en] 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

1985-01-01

268

Heavy tempering of large steel castings and forgings  

International Nuclear Information System (INIS)

When standard grade Cr-Mo-Ni low-alloy steels of high hardenability are employed for manufacture of large castings and forgings of high integrity, their composition can be modified by certain additions. In this article the various effects of Cr, Mo and V are dealt with on the basis of their influence on the properties of the steel grade BS 826M31. The effects of modification, to this steel by increasing the molybdenum content to 1,0% or additions of 0,2% and 0,4% vanadium, on stress relaxation, hardenability, reversible temper embrittlement (RTE), tempering resistance, embrittlement, chemical composition and charpy impact energy are illustrated. 11 refs., 13 figs., 2 tabs

1988-01-01

269

Simulation of Residual Stresses at Holes in Tempered Glass  

DEFF Research Database (Denmark)

This work presents a full 3D numerical study of the residual stresses in tempered (toughened) glass near holes using Narayanaswamy’s model for the tempering process. It is the objective of the paper to elucidate the influence on the minimal residual compressive stresses at holes from variations in: the far-field stress, plate thickness, hole diameter and the interaction between holes and edges and corners. The work presents novel results for the sensitivity of the residual stresses to geometric features and provides a design tool for estimating residual stresses at holes for different geometries. An example of how to extrapolate the results in terms of far-field stresses is given.

Nielsen, Jens Henrik; Olesen, John Forbes

2010-01-01

270

Species diversity of Lachnum (Helotiales, Hyaloscyphaceae) from temperate China*  

Science.gov (United States)

Twenty-three temperate China species of Lachnum, Lachnum abnorme, L. angustum, L. brevipilosum, L. calosporum, L. calyculiforme, L. carneolum, L. ciliare, L. controversum, L. flavidulum, L. cf. fushanese, L. indicum, L. kumaonicum, L. lushanese, L. minutum, L. montanum, L. cf. pteridophyllum, L. pygmaeum, L. sclerotii var. sclerotii, L. sclerotii var. sichuanense, L. subpygmeaum, L. tenuissimum, L. virgineum and L. willisii are reported, whose main characteristics are given in a formula of the described species, some of which are discussed below.

Ye, Ming; Cao, Shu-qing; Jiang, Shao-tong; Pan, Li-jun; Luo, Shui-zhong; Li, Xing-jiang

2006-01-01

271

Species diversity of Lachnum (Helotiales, Hyaloscyphaceae) from temperate China.  

UK PubMed Central (United Kingdom)

Twenty-three temperate China species of Lachnum, Lachnum abnorme, L. angustum, L. brevipilosum, L. calosporum, L. calyculiforme, L. carneolum, L. ciliare, L. controversum, L. flavidulum, L. cf. fushanese, L. indicum, L. kumaonicum, L. lushanese, L. minutum, L. montanum, L. cf. pteridophyllum, L. pygmaeum, L. sclerotii var. sclerotii, L. sclerotii var. sichuanense, L. subpygmeaum, L. tenuissimum, L. virgineum and L. willisii are reported, whose main characteristics are given in a formula of the described species, some of which are discussed below.

Ye M; Cao SQ; Jiang ST; Pan LJ; Luo SZ; Li XJ

2006-01-01

272

Species diversity of Lachnum (Helotiales, Hyaloscyphaceae) from temperate China.  

Science.gov (United States)

Twenty-three temperate China species of Lachnum, Lachnum abnorme, L. angustum, L. brevipilosum, L. calosporum, L. calyculiforme, L. carneolum, L. ciliare, L. controversum, L. flavidulum, L. cf. fushanese, L. indicum, L. kumaonicum, L. lushanese, L. minutum, L. montanum, L. cf. pteridophyllum, L. pygmaeum, L. sclerotii var. sclerotii, L. sclerotii var. sichuanense, L. subpygmeaum, L. tenuissimum, L. virgineum and L. willisii are reported, whose main characteristics are given in a formula of the described species, some of which are discussed below. PMID:16365921

Ye, Ming; Cao, Shu-Qing; Jiang, Shao-Tong; Pan, Li-Jun; Luo, Shui-Zhong; Li, Xing-Jiang

2006-01-01

273

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

2010-01-01

274

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

275

Temperate Pollen Genera in the Eocene (Claiborne) Flora, Alabama.  

Science.gov (United States)

Pollen, spores, hystrichospherids, dinoflagellates, and the fresh-water alga Pediastrum occur in marine clays at the classic Claiborne Bluffs locality, Alabama. The presence of Ephedra pollen provides the first documented Tertiary record of this genus from the southeastern states. The occurrence of several characteristically temperate genera lends support to the idea that a deciduous hardwood forest was present in the Appalachian uplands during the Eocene. PMID:17813748

Gray, J

1960-09-23

276

Temperate Pollen Genera in the Eocene (Claiborne) Flora, Alabama.  

UK PubMed Central (United Kingdom)

Pollen, spores, hystrichospherids, dinoflagellates, and the fresh-water alga Pediastrum occur in marine clays at the classic Claiborne Bluffs locality, Alabama. The presence of Ephedra pollen provides the first documented Tertiary record of this genus from the southeastern states. The occurrence of several characteristically temperate genera lends support to the idea that a deciduous hardwood forest was present in the Appalachian uplands during the Eocene.

Gray J

1960-09-01

277

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.; ELBAZ R.M.; HAMMAD A.M.M.

2013-01-01

278

The influence of tempering temperature on small fatigue crack behavior monitored with surface acoustic waves in quenched and tempered 4140 steel  

Energy Technology Data Exchange (ETDEWEB)

The authors describe their investigation of small surface fatigue crack growth in specially designed cantilevered bending samples of high-purity 4140 steel quenched and tempered to various strength levels. Tempering temperatures of 200 {sup 0}C, 400 {sup 0}C, 550 {sup 0}C and 700 {sup 0}C were used to produce a range of yield strengths and microstructures. Crack propagation and crack closure were monitored with a surface acoustic wave ultrasonic technique. The small crack results were compared to those of long cracks in compact tension samples. Small cracks in the 200 {sup 0}C and 400 {sup 0}C tempers grew at {Delta}{Kappa} levels above their long crack thresholds. Small cracks in the 550 {sup 0}C tempers grew at {Delta}{Kappa} levels slightly below the long crack threshold. The surface cracks in the 700{sup 0}C temper grew well below the long crack threshold showing the small crack effect.

London, B. (McDonnell Douglas Research Labs., St. Louis, MO (USA)); Nelson, D.V. (Stanford Univ., CA (USA). Dept. of Mechanical Engineering); Shyne, J.C. (Failure Analysis Associates, Palo Alto, CA (USA))

1989-07-01

279

Interim report `winter smog and traffic`  

Energy Technology Data Exchange (ETDEWEB)

The title subject is one of the themes of the Dutch national research programme `Air Pollution and Health`. A state of the art is presented of the health effects associated with exposure to winter smog and of the toxicological effects caused by the inhalation of particles. An outline of a plan of activities is given, based on the policy needs and the most serious gaps in knowledge. A review of the literature shows that population exposure to episodes of winter smog is associated with morbidity and mortality. Preliminary results of the epidemiological studies suggest that health effects also occur in the Netherlands. Air quality in terms of annual and daily mean particulate matter with a cut-off diameter of ten micrometer (PM{sub 10} levels) is more or less the same at rural and urban sites. A feasibility study presents an outline for toxicological research most needed to contribute to the causality of the relationship. Quantifying public health risk of acute exposure to winter-type smog with an emphasis on traffic-related air pollution requires the determination of the magnitude of the risk, a generalized insight into the actual exposure of the urban population to winter-type smog and information about the health response originating from such exposure. Insight into the working mechanism(s) underlying the exposure-effect relationship is very scanty. Therefore, further research is necessary to quantify the health risk of the population to winter smog. To corroborate earlier findings the epidemiological research will be continued during the winter 1994/95, personal exposure to PM{sub 10} will be assessed, and air quality characterization is necessary, including particulate matter. Continuation of a CHaracterization of Episodical Air Pollution (CHEAP) project is recommended. (Abstract Truncated)

NONE

1994-12-01

280

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; Kihachiro Kikuzawa

2008-01-01

 
 
 
 
281

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.

1998-01-01

282

Seismic zoning in India  

International Nuclear Information System (INIS)

After a very brief presentation of the concept and procedures for dealing with earthquake data for seismic zoning studies, the seismic zoning studies in India are described in detail. 26 refs, 8 figs.

1988-01-01

283

Transient analysis of a winter greenhouse  

Energy Technology Data Exchange (ETDEWEB)

In this communication, a simple transient analysis of a winter greenhouse has been presented. Due to large fluctuations in day and night temperatures in winter, it is difficult to grow vegetation easily. Greenhouses, therefore, provide an alternative to this problem. Here, the effects of various parameters, viz., isothermal mass, relative humidity, movable insulation, etc., have been incorporated and the effects on the performance of the greenhouse have also been studied. It has been observed that an increase in isothermal mass decreases the fluctuations in plant temperature.

Dutt, D.K.; Rai, S.N.; Tiwari, G.N.; Yadav, Y.P.

1987-01-01

284

Nuclear winter: The evidence and the risks  

Energy Technology Data Exchange (ETDEWEB)

Global concern over nuclear extinction, centered on the holocaust itself, now has turned to the more terrifying consequences of a post-war nuclear winter: ''the long-term effects - destruction of the environment, spread of epidemic diseases, contamination by radioactivity, and ... collapse of agriculture-(that) would spread famine and death to every country.'' Nuclear Winter, the latest in a series of studies by a number of different groups is clinical, analytical, systematic, and detailed. Two physicists and biologist analyze the effects on the climate, plants, animals, and living systems; the human costs; the policy implications.

Greene, O.

1985-01-01

285

Implanting radio transmitters in wintering canvasbacks  

Science.gov (United States)

To conduct telemetry studies of wintering canvasbacks (Aythya valisineria) on Chesapeake Bay, we needed to devise a suitable method of radio transmitter attachment. We describe an aseptic, intra-abdominal surgical technique, using the inhalation anesthetic isoflurane, to implant 20-g radio transmitters in free-ranging canvasbacks. We evaluated the technique over 3 winters (1987-89), when an annual average of 83 female canvasbacks received implant surgery during a 9-day period in mid-December. Of 253 ducks, 248 (98%) were implanted successfully, and 200 (80.6%) completed the 70-day study until early March. No mortality or abnormal behavior from surgery was identified post-release.

Olsen, G. H.; Dein, F. J.; Haramis, G. M.; Jorde, D. G.

1992-01-01

286

Contribution of winter to the annual CH4 emission from a eutrophied boreal lake.  

UK PubMed Central (United Kingdom)

The springtime methane (CH4) emission from a small, eutrophied boreal lake was assessed during the winter ice-cover by measurement of gas ebullition and CH4 accumulation in the water column in association with the development of oxygen depletion after ice formation. The winter CH4 production was estimated to result in a loss of 3.6-7.9 g CH4 m(-2) from the lake to the atmosphere during the short period of ice melt. This could account for 22-48% of the annual CH4 emission from the pelagic zone of the lake. The contribution of winter to the annual CH4 release can be similar or even higher in seasonally ice-covered northern aquatic ecosystems than in northern terrestrial wetlands, thus winter must be considered in any studies into the aquatic CH4 emissions. The trophic state and wintertime oxygen conditions, linked to the changes in land-use in the catchments and climate, are important factors controlling the springtime lake CH4 emissions.

Huttunen JT; Alm J; Saarijärvi E; Lappalainen KM; Silvola J; Martikainen PJ

2003-01-01

287

Contribution of winter to the annual CH4 emission from a eutrophied boreal lake.  

Science.gov (United States)

The springtime methane (CH4) emission from a small, eutrophied boreal lake was assessed during the winter ice-cover by measurement of gas ebullition and CH4 accumulation in the water column in association with the development of oxygen depletion after ice formation. The winter CH4 production was estimated to result in a loss of 3.6-7.9 g CH4 m(-2) from the lake to the atmosphere during the short period of ice melt. This could account for 22-48% of the annual CH4 emission from the pelagic zone of the lake. The contribution of winter to the annual CH4 release can be similar or even higher in seasonally ice-covered northern aquatic ecosystems than in northern terrestrial wetlands, thus winter must be considered in any studies into the aquatic CH4 emissions. The trophic state and wintertime oxygen conditions, linked to the changes in land-use in the catchments and climate, are important factors controlling the springtime lake CH4 emissions. PMID:12653296

Huttunen, Jari T; Alm, Jukka; Saarijärvi, Erkki; Lappalainen, K Matti; Silvola, Jouko; Martikainen, Pertti J

2003-01-01

288

[Climatic potential productivity of winter wheat and summer maize in Huanghuaihai Plain in 2011-2050].  

UK PubMed Central (United Kingdom)

Based on the daily data under B2 climate scenario (2011-2050) and baseline climate condition (1961-1990) extracted from the regional climate model PRECIS, and by using the Agro-Ecological Zone (AEZ) model, a prediction was conducted on the possible spatiotemporal changes of the climatic potential productivity of the two crops in the Huanghuaihai Plain in 2011-2050. Under baseline climate condition, the climatic potential productivities of winter wheat and summer maize presented a regional differentiation, i.e., higher in southeast and lower in northwest regions, and higher along coast and lower in inland at the same latitudes, and fluctuated within the ranges of 3893-11000 kg x hm(-2) and 5908-12000 kg x hm(-2), respectively. Under B2 climate scenario, the climatic potential productivity of winter wheat and summer maize would have a greater inter-annual change, due to the different matching degrees of light, temperature and water during the growth periods of the crops. The climatic potential productivity of winter wheat in 2011-2030 and summer maize in 2021-2040 would have an obvious increase, with great potential for development. Under the conditions of maintaining the present production, the climatic potential productivity of winter wheat in 2011-2050 would present an overall regional differentiation of reverse change in southeast and northwest regions and the same change in coastal and inland areas, whereas the climatic potential productivity of summer maize in 2011-2050 would have little regional differentiation.

Zhao JF; Guo JP; Wu DR; Fang SB; E YH

2011-12-01

289

Standardized precipitation index zones for Mexico  

Energy Technology Data Exchange (ETDEWEB)

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

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

2005-01-01

290

Standardized Precipitation Index Zones for México  

Scientific Electronic Library Online (English)

Full Text Available 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 siete zonas empíricas exclusivamente mexicanas y seis compartidas, derivadas de tres series de imágenes de SPI (Índice Estandarizado de la Precipitación), desde 1940 a (more) 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 (more) (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

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

2005-01-01

291

Simulating phenological shifts in French temperate forests under two climatic change scenarios and four driving global circulation models.  

UK PubMed Central (United Kingdom)

After modeling the large-scale climate response patterns of leaf unfolding, leaf coloring and growing season length of evergreen and deciduous French temperate trees, we predicted the effects of eight future climate scenarios on phenological events. We used the ground observations from 103 temperate forests (10 species and 3,708 trees) from the French Renecofor Network and for the period 1997-2006. We applied RandomForest algorithms to predict phenological events from climatic and ecological variables. With the resulting models, we drew maps of phenological events throughout France under present climate and under two climatic change scenarios (A2, B2) and four global circulation models (HadCM3, CGCM2, CSIRO2 and PCM). We compared current observations and predicted values for the periods 2041-2070 and 2071-2100. On average, spring development of oaks precedes that of beech, which precedes that of conifers. Annual cycles in budburst and leaf coloring are highly correlated with January, March-April and October-November weather conditions through temperature, global solar radiation or potential evapotranspiration depending on species. At the end of the twenty-first century, each model predicts earlier budburst (mean: 7 days) and later leaf coloring (mean: 13 days) leading to an average increase in the growing season of about 20 days (for oaks and beech stands). The A2-HadCM3 hypothesis leads to an increase of up to 30 days in many areas. As a consequence of higher predicted warming during autumn than during winter or spring, shifts in leaf coloring dates appear greater than trends in leaf unfolding. At a regional scale, highly differing climatic response patterns were observed.

Lebourgeois F; Pierrat JC; Perez V; Piedallu C; Cecchini S; Ulrich E

2010-09-01

292

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

293

In vitro protein synthesis capacities in a cold stenothermal and a temperate eurythermal pectinid.  

Science.gov (United States)

The translational system was isolated from the gills of the Antarctic scallop Adamussium colbecki (Smith) and the European scallop Aequipecten opercularis (Linnaeus) for in vitro protein synthesis capacities microg protein mg FW(-1) day(-1)) and the translational capacities of RNA (k(RNA in vitro) mg protein mg RNA(-1) day(-1)). In vitro protein synthesis capacity in the cold-adapted pectinid at 0 degrees C was similar to the one found in the temperate scallop at 25 degrees C. These findings might reflect cold compensated rates in Adamussium colbecki, partly explainable by high tissue levels of RNA. Cold-compensated in vitro protein synthesis capacities may further result from increments in the translational capacity of RNA. The thermal sensitivity of the translation machinery was slightly different in the two species, with significantly lower levels of Arrhenius activation energies E(a) and Q(10) in Adamussium colbecki in the temperature range 0-15 degrees C. Reduced protein synthesis and translational capacities were found in vitro in gills of long-term aquarium-maintained Adamussium colbecki and were accounted for by a loss of protein synthesis machinery, i.e. a reduction in RNA levels, as well as a decrease in the amount of protein synthesized per milligram of RNA (RNA translational capacity, k(RNA in vitro)). Such changes may involve food uptake or mirror metabolic depression strategies, like those occurring during winter. Consequences of high in vitro RNA translational capacities found in the permanently cold-adapted species are discussed in the context of seasonal food availability and growth rates at high latitudes. PMID:12905006

Storch, D; Heilmayer, O; Hardewig, I; Pörtner, H-O

2003-08-06

294

In vitro protein synthesis capacities in a cold stenothermal and a temperate eurythermal pectinid.  

UK PubMed Central (United Kingdom)

The translational system was isolated from the gills of the Antarctic scallop Adamussium colbecki (Smith) and the European scallop Aequipecten opercularis (Linnaeus) for in vitro protein synthesis capacities microg protein mg FW(-1) day(-1)) and the translational capacities of RNA (k(RNA in vitro) mg protein mg RNA(-1) day(-1)). In vitro protein synthesis capacity in the cold-adapted pectinid at 0 degrees C was similar to the one found in the temperate scallop at 25 degrees C. These findings might reflect cold compensated rates in Adamussium colbecki, partly explainable by high tissue levels of RNA. Cold-compensated in vitro protein synthesis capacities may further result from increments in the translational capacity of RNA. The thermal sensitivity of the translation machinery was slightly different in the two species, with significantly lower levels of Arrhenius activation energies E(a) and Q(10) in Adamussium colbecki in the temperature range 0-15 degrees C. Reduced protein synthesis and translational capacities were found in vitro in gills of long-term aquarium-maintained Adamussium colbecki and were accounted for by a loss of protein synthesis machinery, i.e. a reduction in RNA levels, as well as a decrease in the amount of protein synthesized per milligram of RNA (RNA translational capacity, k(RNA in vitro)). Such changes may involve food uptake or mirror metabolic depression strategies, like those occurring during winter. Consequences of high in vitro RNA translational capacities found in the permanently cold-adapted species are discussed in the context of seasonal food availability and growth rates at high latitudes.

Storch D; Heilmayer O; Hardewig I; Pörtner HO

2003-09-01

295

Zoning in zircons  

International Nuclear Information System (INIS)

The TL emission in many zircons is zoned. Because regions of bright TL emission are anti-correlated with regions of high uranium content, age determination by conventional methods give TL dates which are too low. We designed an image intensifier based TL system capable of resolving features on a 5 micron scale during heating in order to detect zoned grains early in the dating procedure. Early rejection of zoned grains would have made the conventional dating approach feasible. However, although polished crystals can unambiguously be identified as being zoned from their TL images, untreated, whole crystals often have superficial features which tend to blur images of the internal zoned light emissions. (author).

1985-01-01

296

Winter meeting on ground water pollution  

International Nuclear Information System (INIS)

At the winter meeting 1995 pollution from the most usual waste disposal sites was discussed: pesticides, chlorinated solvents, sanitary landfills and tar. Transport and biodegradation of pesticides and chlorinated solvents in soils, aquifers and ground water, and remediation means were considered on basis of the Danish and foreign experience. (EG)

1995-01-01

297

Variation In Winter Hardiness Among Safflower Accessions  

Science.gov (United States)

Fall planted safflower (Carthamus tinctorius L.) would provide management alternatives in crop rotations and potentially increase yield. Our objective was to relate several fall growth factors to winter survival in a diverse set of 11 safflower accessions grown at Central Ferry and Pullman WA, USA....

298

CBS Sportsline: The XVII Winter Olympic Games  

Science.gov (United States)

The 18th Winter Olympic Games will be held at Nagano, Japan from February 7 to February 22, 1998. CBS TV is the American network broadcasting the games and its site is highlighted by feature stories about each sport, a schedule of events, rules, and brief individual profiles.

1998-01-01

299

Lake Erie Ice: Winter 1975-76.  

Science.gov (United States)

Ice conditions on Lake Erie depicted mainly from satellite imagery were observed during the winter of 1975-76. The formation, movement, and decay of lake ice were traced at intervals of about 3 days from December 28, 1975, to April 19, 1976. Wind speeds a...

J. H. Wartha

1977-01-01

300

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

Sheikh Mehraj A; Kumar Munesh; Bussmann Rainer W

2009-01-01

 
 
 
 
301

Nondestructive Evaluation of Tempering Process of S45C Steel using DC Potential Drop Measurement  

Energy Technology Data Exchange (ETDEWEB)

DC potential drop(DCPD) measurement system was made and the optimum measuring conditions have been studied. The room temperature resistivity of commercially available medium carbon steel(S45C) was measured using this technique. DCPD was measured in the specimens which were hardened and tempered at different temperatures. It was found that DCPD reflected the change of the microstructure during tempering very sensitively. It was possible to monitor the stage of tempering of S45C steel nondestructively using DCPD measurement

Park, Y. K.; Ahn, B. Y. [Korea Standards Research Institute, Daejeon (Korea, Republic of)

1989-05-15

302

Discovering the importance of lateral CO2 transport from a temperate spruce forest  

International Nuclear Information System (INIS)

Our study investigated the concentration of dissolved carbon at the point when water leaves the pedosphere and whether this amount represents a significant proportion of terrestrial carbon cycling. The investigations were carried out in a temperate forest catchment (Black Forest, Germany) over a period of 1 year. The annual export of dissolved C compounds (14.4 g C m-2 year-1) was dominated by CO2 (9.7 vs. 4.7 g C m-2 year-1 DOC). Even though the direct CO2 degassing at the spring was inferior (0.4 kg C year-1), considerably lower CO2 concentrations were measured 17 m downstream of the spring. This shows that a large proportion of dissolved CO2 (93%) originating from the pedosphere is not captured anymore within a short distance from the spring. The measured lateral C-transport was in the same order of magnitude as reported for the net ecosystem exchange (NEE) observed for German spruce forests (-4 to -55 g C m-2 year-1). Therefore, the results clearly demonstrated that the lateral transport of dissolved carbon can be a significant part of terrestrial carbon budgets and for this study site CO2 was dominating this 'indirect' pathway. However, for generalisation, it is important to extend this investigation to other landscapes and climatic zones. (author)

2006-09-15

303

Simulating the carbon balance of a temperate larch forest under various meteorological conditions  

Directory of Open Access Journals (Sweden)

Full Text Available Abstract Background Changes in the timing of phenological events may cause the annual carbon budget of deciduous forests to change. Therefore, one should take such events into account when evaluating the effects of global warming on deciduous forests. In this article, we report on the results of numerical experiments done with a model that includes a phenological module simulating the timing of bud burst and other phenological events and estimating maximum leaf area index. Results This study suggests that the negative effects of warming on tree productivity (net primary production) outweigh the positive effects of a prolonged growing season. An increase in air temperature by 3°C (5°C) reduces cumulative net primary production by 21.3% (34.2%). Similarly, cumulative net ecosystem production (the difference between cumulative net primary production and heterotrophic respiration) decreases by 43.5% (64.5%) when temperatures are increased by 3°C (5°C). However, the positive effects of CO2 enrichment (2 × CO2) outweigh the negative effects of warming ( Conclusion Although the model was calibrated and validated for a specific forest ecosystem, the implications of the study may be extrapolated to deciduous forests in cool-temperate zones. These forests share common features, and it can be conjectured that carbon stocks would increase in such forests in the face of doubled CO2 and increased temperatures as long as the increase in temperature does not exceed 5°C.

Toda Motomu; Yokozawa Masayuki; Sumida Akihiro; Watanabe Tsutomu; Hara Toshihiko

2007-01-01

304

Toward enabling winter occupations: testing a winter coat designed for older adults.  

UK PubMed Central (United Kingdom)

BACKGROUND: Previous research indicates that older adults have difficulties using winter clothing, which contributes to their risk of isolation during winter. Research has also shown that a winter coat that requires less flexibility, strength, and dexterity would help support this population. PURPOSE: This pilot study evaluated the measured and perceived effectiveness of a winter coat prototype that had a funnel sleeve design. METHODS: Eight older adults trialed three coats (the participant's own coat, a coat fitted with sleeve gripper, and the prototype coat), which were evaluated though shoulder range of motion measurements and by the participant completing a survey. FINDINGS: Less shoulder range of motion was used to put on the prototype coat. Survey findings support range of motion data that Sleeve Gripper has limited utility. IMPLICATIONS: A funnel sleeve design may require less range of motion at the shoulder compared to other coats.

Green SL; Boger JN; Mihailidis A

2011-02-01

305

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

International Nuclear Information System (INIS)

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

2004-01-01

306

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

Energy Technology Data Exchange (ETDEWEB)

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

Kryshev, A.; Sazykina, T. [Scientific anf Production Association Typhoon, Obninsk, Kaluga Region (Russian Federation)

2004-07-01

307

Recent carbonate sedimentation on Balearic platform: model for temperate-climate carbonate shelves  

Energy Technology Data Exchange (ETDEWEB)

Existing models for carbonate sedimentation on continental platforms are derived from the study of modern carbonate platforms in tropical climates. The Balearic platform in the western Mediterranean provides a new model for carbonate sedimentation in a temperature, semiarid climate. On most of the continental shelf around the Balearic Islands, modern sediments are exclusively bioclastic carbonates. Shoreline carbonate sediments are bioclastic sands and muds accumulating in beach-dune systems without significant tidal influence (there are no astronomical tides in the western Mediterranean ). From the upper shoreface to 35 m deep, the sandy bottom is extensively colonized by sea grass (Posidonia oceanica), the rhizomes and roots of which form a rigid entrapment that retains the sediment derived from calcareous organisms living within the sea grass and from calcareous epiphytes living on the stems and leaves. Archeological dating establishes a rate of vertical accretion in this zone of 10/sup 3/ Bubnoff units (1 Bubnoff unit = 1 mm/1000 years). Between depths of 40 and 60 m, carbonate sands are composed predominantly or red-algal fragments. Intensely bioturbated wave ripples occur in environments dominated by laminar red algae (Lithothamnium and Phymatolithon). Below depths of 60 m, coarse sediment produced by rhodolitic and ramose red algae is deposited in areas of tens to hundreds of meters in size. Biogenic buildups up to 2 m high occur in sandy areas as well as in deeper muddy areas. At the same depth in open-platform zones, the bottom topography is characterized by large hummocks several hundred meters across. From the horizontal distribution of facies, it is possible to construct the probable vertical sequence of lithofacies which would characterize carbonates accumulating on a temperate-climate carbonate shelf. Many of these lithofacies are recognized in upper Miocene limestones on the Balearic Islands.

Fornos, J.; Rodriguez-Perea, A.; Massuti, C.; Pomar, L.; Acosta, J.; Herranz, P.; Sanz, J.L.

1989-03-01

308

Interhemispheric temperature difference as a predictor of boreal winter ENSO  

Science.gov (United States)

We use statistical analysis to show statistically significant relationship between the boreal winter MEI index of ENSO and HadCRUT3 temperature difference between Northern and Southern hemispheres (NH - SH) during the preceding summer. Correlation values increase (in absolute terms) if the correlated time periods are increased from month to seasonal length. For example December and January (DJ) MEI values anticorrelate stronger with the preceding MJJA period than with any of the four months taken separately. We believe this is further evidence that the correlation is caused by a real physical process as increase of the averaging period tends to reduce statistical noise. The motivation for looking for such a relationship comes from review of literature on paleoclimatic ENSO behavior. We have noticed that in many cases relatively cold NH coincided with "strong ENSO" (frequent El Niños), for example the Ice Age periods and Little Ice Age. On the other hand periods of relatively warm NH (the Holocene climate optimum or Medieval Climate Anomaly) are coincident with frequent or even "permanent" La Niñas. This relationship suggest the influence of the position of Intertropical Convergence Zone (ITCZ) on the frequency of El Niños. The simplest physical mechanism of the relationship is that the positive (negative) NH-SH temperature difference causes a north (south) shift of ITCZ with a parallel shift of trade wind zones. The North-South orographic difference between the Panama Isthmus and the South America may cause stronger (weaker) trade winds in Eastern Tropical Pacific increasing (decreasing) the thermochemical tilt which, in turn, causes a more negative (positive) ENSO values. Of course this may be only a first approximation of the real mechanism of this "teleconnection". The correlations we have found are not strong even if statistically significant. For example, the MJJA NH-SH temperature vs. DJ MEI correlation has r = -0.28 implying it explains only 8% of boreal winter ENSO variability. In, fact, we did not expect a high value for a phenomenon which is a self-regulated ocean-atmosphere oscillation with timing partly triggered by stochastic atmospheric forcing, especially as we predict ENSO with (semi)global parameters. It is possible that further research may identify smaller regions of both hemispheres which temperature differences explain a larger part of ENSO variability. However in our opinion, the importance of this result is that it may not only improve ENSO prediction but also help in better understanding of ENSO variability in different time scales.

Piskozub, Jacek; Gutowska, Dorota

2013-04-01

309

Winter climate variability and classification in the Bulgarian Mountainous Regions  

International Nuclear Information System (INIS)

[en] The problems of snowiness and thermal conditions of winters are of high interest of investigations because of the more frequent droughts, occurred in the region. In the present study an attempt to reveal tendencies existing during the last 70 years of 20 th century in the course winter precipitation and,temperature as well as in some of the snow cover parameters. On the base of mean winter air temperature winters in the Bulgarian mountains were analyzed and classified. The main results of the study show that winter precipitation has decrease tendencies more significant in the highest parts of the mountains. On the other hand winter air temperature increases. It shows a relatively well-established maximum at the end of the studied period. In the Bulgarian mountains normal winters are about 35-40% of all winters. (Author)

2004-01-01

310

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.

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

2006-01-01

311

Temperate bacteriophage infectious for asporogenic variants of Bacillus pumilus.  

UK PubMed Central (United Kingdom)

Bacillus pumilus strain NRRL B-3275 is lysogenic for an inducible, nondefective temperate bacteriophage phi75. phi75 infects and lysogenizes several asporogenic mutants of B. pumilus strain NRS 576 but does not productively infect the spore(+) parent. phi75 DNA is a linear duplex with a mol wt of about 29 x 10(6) and a buoyant density of 1.701 g/cm(3). The location of the phi75 prophage attachment site on the chromosome of both host strains is adjacent to a lysine marker. The apparent order is phi75 att lys trp.

Bramucci MG; Lovett PS

1974-11-01

312

Temperate bacteriophage infectious for asporogenic variants of Bacillus pumilus.  

Science.gov (United States)

Bacillus pumilus strain NRRL B-3275 is lysogenic for an inducible, nondefective temperate bacteriophage phi75. phi75 infects and lysogenizes several asporogenic mutants of B. pumilus strain NRS 576 but does not productively infect the spore(+) parent. phi75 DNA is a linear duplex with a mol wt of about 29 x 10(6) and a buoyant density of 1.701 g/cm(3). The location of the phi75 prophage attachment site on the chromosome of both host strains is adjacent to a lysine marker. The apparent order is phi75 att lys trp. PMID:4431081

Bramucci, M G; Lovett, P S

1974-11-01

313

Taxonomic significance of flavonoid variation in temperate species of Nothofagus.  

Science.gov (United States)

Forty-two flavonoids and a stilbene (pinosylvin) were identified in the leaf exudates of 11 temperate species of Nothofagus from South America, Australia and New Zealand. The flavonoid profiles demonstrate significant taxonomic value at the subgeneric level. Most species of subgenus Fuscospora are characterized by the presence of pinosylvin, galangin and galangin methyl ethers. Kaempferol-type flavonols are abundant in subgenus Lophozonia while these flavonols are largely absent from species of subgenus Fuscospora. The flavonoid patterns are largely in agreement with a recent subgeneric classification of Nothofagus. PMID:12591267

Wollenweber, Eckhard; Stevens, Jan F; Dörr, Marion; Rozefelds, Andrew C

2003-04-01

314

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.

Wu Beihua; Wang Yongquan

2012-01-01

315

Aquatic fungi parasitic on temperate fishes of Kumaun Himalaya, India.  

UK PubMed Central (United Kingdom)

Eighty isolates of different species of aquatic fungi belonging to Achlya, Aphanomyces, Dictyuchus, Protoachlya, Saprolegnia, Thraustotheca and Pythium are observed as parasites of certain temperate fish of Kumaun Himalaya, India. The parasitic ability of each isolate was confirmed by artificial inoculation experiments under laboratory conditions. The genera of Saprolegnia and Achlya were more virulent fish parasites than Aphanomyces, Dictyuchus, Protoachlya, Thraustotheca and Pythium. All the fish species observed are new hosts for these pathogens. Protoachlya paradoxa, Achlya klebsiana, Thraustotheca clavata and Pythium undulatum are reported for the first time as natural pathogens of fish.

Sati SC

1991-09-01

316

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

DEFF Research Database (Denmark)

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

Carter, Mette Sustmann; Ambus, Per

2011-01-01

317

Genetic diversity of the endangered scaly-sided merganser (Mergus squamatus) in the wintering habitat of central-southern China.  

UK PubMed Central (United Kingdom)

The scaly-sided merganser (Mergus squamatus), found in temperate East Asia, has been reduced to a very small population. Central and southern China are its main wintering habitat. However, populations have declined greatly since the 1980s due to habitat loss and degradation, and poaching. To meet the urgent need for up-to-date conservation information, we examined RAPD DNA markers from 156 specimens in 6 populations in Jiangxi Province. We found that genetic diversity (based on individual similarities) is in fact low; molecular variance between populations ranged from 0.137 to 0.347. Genetic similarity ranged from 0.683 to 0.866. In conclusion, the geographical pattern of genetic diversity supports the long-term refugial status of the scaly-sided merganser in central-southern China; strong conservation measures should be taken to maintain the merganser in this region.

Zhang ZQ; Qin CJ; Fang DA; Wang AP; Luo CH; Liu K

2013-01-01

318

Polygonal Fresnel zone plates  

Science.gov (United States)

The performance of Fresnel zone plates having a polygonal boundary between zones has been studied. The contribution of the complex amplitude of each zone is calculated analytically and numerically solved. The case of a continuous phase plate is considered as the limit case in performance for each polygonal shape. This performance is compared with respect to the circular case. Also four different methods to define a polygonal FZP having discrete phase shift are analyzed and compared.

Alda, Javier; González, Francisco Javier

2009-08-01

319

ECONOMIC EFFICIENCY OF THE WINTER WHEAT (TRITICUM AESTIVUM L.) AND WINTER SPELT (TRITICUM SPELTA L.) GROWING IN ORGANIC FARMING  

Directory of Open Access Journals (Sweden)

Full Text Available Comparison of economic efectivity of the winter wheat (Triticum aestivum L.) and winter spelt (Triticum spelta L.) growing in organic farming systems. The differences of yield of two species wheats in organic farming system and factors are evaluated. In relation to standart technological procedures in farming systems are defined costs for area nad for production unit. Structure of costs on production, price differences between the winter wheat and winter spelt are analysed.

J. ŠRÁMEK; P. KONVALINA; I. ZDRHOVÁ; J. MOUDRÝ jr.; J. MOUDRÝ

2009-01-01

320

[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

2008-04-25

 
 
 
 
321

How to winterize your mining equipment  

Energy Technology Data Exchange (ETDEWEB)

In addition to regular year-round preventive maintenance procedures outlined in equipment operator's manuals, a number of special considerations should be taken into account when mining equipment will be operated in the sub-freezing temperatures of winter. This article outlines some general considerations of systems common to most Diesel-powered heavy equipment as well as specific precautions and procedures to be followed in preparing given pieces of euqipment for winer time operation.

Alm, B.

1980-12-01

322

Tracking a Winter Storm Across the USA  

Science.gov (United States)

In this activity, students track a real winter storm, collect imagery and data, perform an analysis, and make predictions on the storm's path. They will summarize their findings by writing a press release for their local radio station or by producing a report with visuals and graphics for a television broadcast. Instructions for downloading and processing data, images, and weather reports are presented along with ideas for graphing and viewing the material. Extension activities are also provided.

323

Nuclear winter - Physics and physical mechanisms  

International Nuclear Information System (INIS)

[en] The basic physics of the environmental perturbations caused by multiple nuclear detonations is explored, summarizing current knowledge of the possible physical, chemical, and biological impacts of nuclear war. Emphasis is given to the impact of the bomb-generated smoke (soot) particles. General classes of models that have been used to simulate nuclear winter are examined, using specific models as examples. 81 refs

1991-01-01

324

Race against the onset of winter  

Energy Technology Data Exchange (ETDEWEB)

This article traces the race to provide power supplies in war torn Kosovar for the returning refugees before the onset of winter. The challenges in repairing the power system in Kosovar are listed, and the conditions of the Kosovar A and B plants, the transmission system, the urgent remedial action required, interconnectors to surrounding countries, the role of the armed forces, and the new structure are discussed. (UK)

Flin, D.

1999-12-01

325

Mitochondrial ageing of a polar and a temperate mud clam.  

UK PubMed Central (United Kingdom)

We investigated mitochondrial ageing in a temperate (Mya arenaria) and an Antarctic (Laternula elliptica) mud clam, with similar lifestyle (benthic filter feeders) but different maximum life spans (MLSP), 13 and 36 years, respectively. The short-lived temperate M. arenaria showed a more pronounced decrease in mitochondrial function (respiration, respiratory control ratio, proton leak, membrane potential) with age than the long-lived Antarctic L. elliptica. H2O2 generation rates at habitat temperature were far higher in the short-lived M. arenaria compared to L. elliptica. Reactive oxygen species (ROS) production as proportion of the mitochondrial oxygen consumption rate (%H2O2/O2) increased significantly with age in M. arenaria, whereas in L. elliptica the proportion remained unchanged. Lower rates of mitochondrial H2O2 generation were presumably due to mild uncoupling as L. elliptica mitochondria showed higher proton leak compared to M. arenaria mitochondria. The results are discussed in to the light of the "Free Radical-Rate of Living theory", (Pearl, R., 1928. The Rate of Living. Alfred Knopf, New York; Harman, D., 1956. Aging: a theory based on free radical and radiation biology. J. Gerontol. 11, 298-300) and the "Uncoupling to Survive" hypothesis (Brand, M.D., 2000. Uncoupling to survive? The role of mitochondrial inefficiency in ageing. Exp. Gerontol. 35, 811-820).

Philipp E; Pörtner HO; Abele D

2005-05-01

326

Methyl bromide and methyl chloride fluxes from temperate forest litter  

Science.gov (United States)

Methyl halide fluxes were measured from fine (nonwoody) litter samples at a temperate deciduous forest site in Scotland on 16 occasions over more than a year and at a coniferous forest site. The resulting mean (±1 sd) CH 3Br and CH 3Cl fluxes were 4.1 ± 3.7 ng kg -1 h -1 and 0.98 ± 0.62 ?g kg -1 h -1, respectively, for dry mass leaf litter and 5.7 ± 6.3 ng kg -1 h -1 and 0.47 ± 0.14 ?g kg -1 h -1 for dry mass needle litter. Temporal variations of net fluxes from leaf litter were significantly greater than spatial variations suggesting seasonality in the fluxes. The mean CH 3Cl/CH 3Br mass ratio of fluxes was ˜200 (to 1 sig. fig.), an order of magnitude larger than the ratio of their estimated global turnovers. Temperate forest litter may be a moderate net source of CH 3Cl globally but a negligible source of CH 3Br. These statements refer to the nonwoody litter component only.

Blei, Emanuel; Heal, Mathew R.

2011-03-01

327

Parallel Tempering for sampling and optimization in seismic inverse problems  

Science.gov (United States)

The field of seismology is rich with inverse problems. Seismologists are constantly seeking new ways to use seismic waveforms, and data products derived from them, to constrain subsurface structure in the form of Earth properties in 1-, 2- and 3 dimensions, as well as seismic sources in space and time. Every approach has its limitations and a virtual smorgasbord of methods exist, and have been applied over thirty years, with varying degrees of success. In this presentation we discuss a new class of approach. Parallel Tempering (PT) is a technique originating in the field of computational statistics that is finding increasing success for probabilistic sampling problems in astro and quantum physics, and more recently ocean acoustics but appears to be virtually unknown in the solid earth geosciences. In seismology two classes of inference approach are common for nonlinear inverse problems, Bayesian (probabilistic) sampling and optimization. Parallel Tempering can be applied to both situations and is related to better known methods such as Simulated Annealing and Metropolis Sampling. PT is distinguished as it has a theoretical basis for being superior to both. PT is best viewed as a `meta' algorithm. In a sense wrapping around existing optimization or Bayesian sampling methods to facilitate more robust performance (optimization) and more rapid exploration of parameter space (sampling). PT has generated much interest across the physical sciences with encouraging results emerging. This presentation will describe the basic ideas, and present results of implementations on seismic waveform inversion for both sampling and optimization.

Sambridge, Malcolm

2013-04-01

328

Type 1,1-operators on spaces of temperate distributions  

DEFF Research Database (Denmark)

This paper is a follow-up on the author’s general definition of pseudo-differential operators of type 1,1, in Hörmander’s sense. It is shown that such operators are always defined on the smooth functions that are temperate; and moreover are defined and continuous on the space of temperate distributions, whenever they fulfil the twisted diagonal condition of Hörmander, or more generally when they belong to the self-adjoint subclass. Continuity in Lp -Sobolev spaces and Hölder–Zygmund spaces, and more generally in Besov and Lizorkin–Triebel spaces, is for positive smoothness also proved on the basis of the definition. These continuity results are extended to arbitrary real smoothness indices for operators that fulfil the twisted diagonal condition or belong to the self-adjoint subclass. With systematic Littlewood–Paley analysis the well-known paradifferential decomposition is also derived for type 1,1-operators. The proofs are based on a spectral support rule for pseudo-differential operators in combination with pointwise estimates in terms of maximal functions.

Johnsen, Jon

2010-01-01

329

Assessment, management, and prevention of childhood temper tantrums.  

UK PubMed Central (United Kingdom)

PURPOSE: To provide an overview of normal and abnormal temper tantrum behavior as well as give recommendations nurse practitioners (NPs) can use in counseling families. DATA SOURCES: Articles were identified from the following databases: CINAHL, HEALTH SOURCE: Nursing/Academic edition, Medline, Social Work Abstracts, Social Science Abstracts, Psych INFO, Psychology and Behavioral Science Collection. Textbook references were also identified using Stat!Ref. CONCLUSIONS: Temper tantrums are one of the most common behavior problems in children. Although most children will have tantrums, with NPs' support and guidance in primary care encounters, most children will not require further intervention. IMPLICATIONS FOR PRACTICE: NPs caring for children will need to identify normal and abnormal tantrum behavior as well as rule out other causes of tantrums in order to help parents handle the tantrum behavior. To obtain CE credit for this activity, go to http://www.aanp.org and click on the CE Center. Locate the listing for this article and complete the post-test. Follow the instructions to print your CE certificate.

Daniels E; Mandleco B; Luthy KE

2012-10-01

330

Connectivity within and among a network of temperate marine reserves.  

UK PubMed Central (United Kingdom)

Networks of marine reserves are increasingly being promoted as a means of conserving marine biodiversity. One consideration in designing systems of marine reserves is the maintenance of connectivity to ensure the long-term persistence and resilience of populations. Knowledge of connectivity, however, is frequently lacking during marine reserve design and establishment. We characterise patterns of genetic connectivity of 3 key species of habitat-forming macroalgae across an established network of temperate marine reserves on the east coast of Australia and the implications for adaptive management and marine reserve design. Connectivity varied greatly among species. Connectivity was high for the subtidal macroalgae Ecklonia radiata and Phyllospora comosa and neither species showed any clear patterns of genetic structuring with geographic distance within or among marine parks. In contrast, connectivity was low for the intertidal, Hormosira banksii, and there was a strong pattern of isolation by distance. Coastal topography and latitude influenced small scale patterns of genetic structure. These results suggest that some species are well served by the current system of marine reserves in place along this temperate coast but it may be warranted to revisit protection of intertidal habitats to ensure the long-term persistence of important habitat-forming macroalgae. Adaptively managing marine reserve design to maintain connectivity may ensure the long-term persistence and resilience of marine habitats and the biodiversity they support.

Coleman MA; Chambers J; Knott NA; Malcolm HA; Harasti D; Jordan A; Kelaher BP

2011-01-01

331

Connectivity within and among a network of temperate marine reserves.  

Science.gov (United States)

Networks of marine reserves are increasingly being promoted as a means of conserving marine biodiversity. One consideration in designing systems of marine reserves is the maintenance of connectivity to ensure the long-term persistence and resilience of populations. Knowledge of connectivity, however, is frequently lacking during marine reserve design and establishment. We characterise patterns of genetic connectivity of 3 key species of habitat-forming macroalgae across an established network of temperate marine reserves on the east coast of Australia and the implications for adaptive management and marine reserve design. Connectivity varied greatly among species. Connectivity was high for the subtidal macroalgae Ecklonia radiata and Phyllospora comosa and neither species showed any clear patterns of genetic structuring with geographic distance within or among marine parks. In contrast, connectivity was low for the intertidal, Hormosira banksii, and there was a strong pattern of isolation by distance. Coastal topography and latitude influenced small scale patterns of genetic structure. These results suggest that some species are well served by the current system of marine reserves in place along this temperate coast but it may be warranted to revisit protection of intertidal habitats to ensure the long-term persistence of important habitat-forming macroalgae. Adaptively managing marine reserve design to maintain connectivity may ensure the long-term persistence and resilience of marine habitats and the biodiversity they support. PMID:21625388

Coleman, Melinda A; Chambers, Justine; Knott, Nathan A; Malcolm, Hamish A; Harasti, David; Jordan, Alan; Kelaher, Brendan P

2011-05-23

332

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; R. Hüppi; J. Leifeld; A. Neftel

2012-01-01

333

The investigation of applicability of the Hollomon-Jaffe equation on tempering the HSLA steel  

Directory of Open Access Journals (Sweden)

Full Text Available High strength low-alloyed (HSLA) Cr-Mn-Si steels belong to a group of steels that can reach their full mechanical properties after quenching and tempering. Those properties depend both on the temperature and time of tempering. Knowing the tempering parameters, it is possible to reach the desired properties of the treated steel. Some results on investigating the Hollomon-Jaffe equation (in parametric form) application for tempering of HSLA steel, are shown in this paper. The experiments were performed in real production conditions, using a standard material. The quenching was performed at 870 ?C, the heating period was always 30 min, with subsequent cooling into the oil bath. The tempering was carried out in temperature range from 480 to 680 ?C, while tempering time varied from 15 min to 24 h. The degree of tempering is referred through the hardness values changing. The experimental results have shown a pretty well agreement to tempering parameters, included in Hollomon- -Jaffe equation, for this kind of HSLA steel.

Z. Janjuševi?; Z. Gulišija; M. Mihailovi?; A. Patari?

2009-01-01

334

Effect of tempering temperature on microstructure and mechanical properties of high boron white cast iron  

Directory of Open Access Journals (Sweden)

Full Text Available The effect of different tempering temperatures on the microstructure and mechanical properties of air-quenched high boron white cast iron was studied. The results indicate that the high boron white cast iron comprises dendritic matrix and inter-dendritic M2B boride; and the matrix comprises martensite and pearlite. After quenching in the air, the matrix is changed into lath martensite; but only 1-?m-size second phase exists in the matrix. After tempering, another second phase of several tens of nanometers is found in the matrix, and the size and quantity increase with an increase in tempering temperature. The two kinds of second precipitation phase with different sizes in the matrix have the same chemical formula, but their forming stages are different. The precipitation phase with larger size forms during the austenitizing process, while the precipitation phase with smaller size forms during the tempering process. When tempered at different temperatures after quenching, the hardness decreases with an increase in the tempering temperature, but it increases a little at 450 ? due to the precipitation strengthening effect of the second phase, and it decreases greatly due to the martensite decomposition above 450 ?. The impact toughness increases a little when tempered below 300 ?, but it then decreases continuously owing to the increase in size and quantity of the secondary precipitate above 300 ?. Considered comprehensively, the optimum tempering temperature is suggested at 300 ? to obtain a good combination of hardness and toughness.

Liu Zhongli; Li Yanxiang; Chen Xiang

2012-01-01

335

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,C)6. After solution treated at 1,050 °C and followed by oil cooling, the amount of M23(B,C)6 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; Du Zhongze; Li Ping

2012-01-01

336

Wetlands, climate zones and Barmah Forest virus disease in Queensland, Australia.  

UK PubMed Central (United Kingdom)

Barmah Forest virus (BFV) disease is the second most common mosquito-borne disease in Australia, but the linkages of the wetlands and climate zones with BFV transmission remain unclear. We aimed to examine the relationship between the wetlands, climate zones and BFV risk in Queensland, Australia. Data on the wetlands, climate zones, population and BFV cases for the period 1992 to 2008 were obtained from relevant government agencies. BFV risk was grouped as low-, medium- and high-level based on BFV incidence percentiles. The buffer zones around each BFV case were made using 1, 5, 10, 15, 20, 25 and 50km distances. We performed a discriminant analysis to determine the differences between wetland classes and BFV risk within each climate zone. The discriminant analyses show that saline 1, riverine and saline tidal influence were the most significant contributors to BFV risk in all climate and buffer zones, while lacustrine, palustrine, estuarine and saline 2 and saline 3 wetlands were less important. These models had classification accuracies of 76%, 98% and 100% for BFV risk in subtropical, tropical and temperate climate zones, respectively. This study demonstrates that BFV risk varies with wetland class and climate zone. The discriminant analysis is a useful tool to quantify the links between wetlands, climate zones and BFV risk.

Naish S; Mengersen K; Hu W; Tong S

2012-12-01

337

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

338

Adaptive Markov chain Monte Carlo for auxiliary variable method and its application to parallel tempering.  

Science.gov (United States)

Auxiliary variable methods such as the Parallel Tempering and the cluster Monte Carlo methods generate samples that follow a target distribution by using proposal and auxiliary distributions. In sampling from complex distributions, these algorithms are highly more efficient than the standard Markov chain Monte Carlo methods. However, their performance strongly depends on their parameters and determining the parameters is critical. In this paper, we proposed an algorithm for adapting the parameters during drawing samples and proved the convergence theorem of the adaptive algorithm. We applied our algorithm to the Parallel Tempering. That is, we developed an adaptive Parallel Tempering that tunes the parameters on the fly. We confirmed the effectiveness of our algorithm through the validation of the adaptive Parallel Tempering, comparing samples from the target distribution by the adaptive Parallel Tempering and samples by conventional algorithms. PMID:23500498

Araki, Takamitsu; Ikeda, Kazushi

2013-02-13

339

Soil animal communities and their seasonal change in the greening litters of different functional zones in Baoshan Steel Plant, Shanghai  

Directory of Open Access Journals (Sweden)

Full Text Available To find out the relationship between the abundance and diversity of soil animals and soil characteristics in industrial zones, we investigated soil animals in litters of different functional zones in Baoshan Steel Plant. A total of 52,070 soil animals were collected using Tullgren funnel, belonging to three phyla, 10 classes and 19 orders. The dominant groups were Arcarina and Collembola, accounting for 90.60% of the total in terms of individual numbers. The common groups were Lepidoptera and Oligochaeta plesiopora. The results indicated that different functional zones had similar dominant groups but different common groups. Soil animal reduced along a gradient of production zone, transition zone, office zone. Similarity index showed that the five indices were different in different functional zones. The density-group index (DG) showed the following pattern: production zone > transition zone >office zone. The seasonal change of the total number of soil animals were ranked as: winter>autumn>summer>spring, while the number of soil animal groups were ranked as: winter=autumn>summer=spring. The pH, TOC, TN and TP of litters in different functional zones were different, which might have impacts on the distribution of soil animals.

Jinfeng Wang; Wenhui You; Lan Yi

2007-01-01

340

Effects of a moderate sized city on human thermal bioclimate during clear winter nights  

Science.gov (United States)

The human thermal bioclimatic effects of urbanization and natural topographic features (the ocean and hills) were investigated during clear winter nights in Christchurch, New Zealand. Results are presented in terms of the amount of clothing insulation required to balance the body heat budget equation of a standing person with no change in body heat storage. The ordering of urban-rural land use zones from lowest to highest clothing requirements was: CBD, light industrial-commercial, residential and rural. Air temperature accounted for most of the variation in clothing requirement with the model used and weather conditions investigated here followed by environmental thermal radiation. The oceans and hill slopes had an effect comparable to that of most of the urban area and required less clothing than did all land use zones except the urban CBD.

Tuller, S. E.

1980-03-01

 
 
 
 
341

Liana habitat and host preferences in northern temperate forests  

UK PubMed Central (United Kingdom)

Lianas and other climbers are important ecological and structural components of forest communities. Like other plants, their abundance in a given habitat depends on a variety of factors, such as light, soil moisture and nutrients. However, since lianas require external support, host tree characteristics also influence their distribution. Lianas are conspicuous life forms in tropical regions, but in temperate areas, where they are less prominent, little is known about factors that control their distributions in these forests. We surveyed the climbing plant species in 20 mature (100 years and greater) forested habitats in the Midwest USA at a variety of levels from simple presence/absence, to ground layer abundances, to those species that had ascended trees. We also examined attributes of the tree species with climbers attached to them. Using cluster analysis, we distinguished five different tree communities in our survey locations. We determined that 25% of the trees we surveyed had one or more lianas attached to it, with Parthenocissus quinquefolia (Virginia creeper) the most common climbing species encountered. Canopy cover and soil attributes both influenced climber species presence/absence and ground layer climber abundance. The proportion of liana species of a given climbing type (roots, stem twiner, tendril climber) was significantly related to the DBH of the host tree, with more root climbers and fewer stem and tendril climbers on large trees. In general, the DBH of climbing lianas had a significant positive relationship to the DBH of the host tree; however this varied by the identity of the liana and the tree species. The greater the DBH of the host tree, the higher the probability that it was colonized by one or more lianas, with tree species such as Pinus banksiana (jack pine) and Quercus alba (white oak) being more susceptible to liana colonization than others. Finally, some liana species such as Celastrus scandens (American bittersweet) showed a preference for certain tree species (i.e., P. banksiana) as hosts. The information obtained about the relationship between the tree and climber community in this study provides insight into some of the factors that influence liana distributions in understudied temperate forest habitats and how lianas contribute to the structure of these mature forests. In addition, these data can provide a point of comparison to other liana communities in both temperate and tropical regions.

Leicht-Young StaceyA; Pavlovic NoelB; Frohnapple KrystalynnJ; Grundel Ralph

2010-09-01

342

Multi-zone furnace system  

Energy Technology Data Exchange (ETDEWEB)

A multi-zone furnace is described which consists of: a furnace chamber having at least one heat zone and at least one zone adjacent to the heat zone and disposed along the length of the furnace chamber; the heat zone having a hearth at a level different from the hearth level of the adjacent zone; a walking beam conveyor disposed in the furnace chamber and operative in a short stroke mode to convey a product along the hearth of the heat zone, and in a long stroke mode to convey a product from the heat zone to the adjacent zone.

Orbeck, G.A.

1986-05-06

343

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.

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

2012-01-01

344

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; Ibáñez, Marcelo A.; Bru, Elena; Manes, Mario E.

2002-01-01

345

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

Scientific Electronic Library Online (English)

Full Text Available Abstract in portuguese A biodiversidade de protistas heterotróficos é pouco conhecida na zona costeira do Atlântico Sul (~32 °S), especialmente dos nanoflagelados. No presente estudo, foi registrada pela primeira vez a presença de coanoflagelados loricados no estuário da Lagoa dos Patos e na zona costeira adjacente. Dezessete espécies de onze gêneros de coanoflagelados loricados foram observadas em amostras de água fixadas (solução de lugol + glutaraldeido) coletadas entre outubro de (more) 1998 e maio de 2000, e analisadas em microscópio de transmissão JEM 100-SX. A maior parte das espécies foi registrada em águas euhalinas e mixopolihalinas durante a primavera e o verão, nenhuma no outono e poucas (quatro) no inverno. A ausência de coanoflagelados nas estações mais protegidas deve-se a influência da água doce, e na estação da praia deve-se, provavelmente, a forte ação das ondas. As espécies, provavelmente cosmopolitas, Pleurasiga minima, Cosmoeca norvegica, C. ventricosa and Parvicorbicula circularis ocorreram na primavera ou no verão no canal principal do estuário e na área costeira, enquanto Stephanoeca diplocostata, que aparentemente prefere baixas temperaturas, foi registrada no inverno. Calotheca alata e Campyloacantha spinifera são principalmente de ambientes temperados e estiveram presentes na primavera. Uma espécie nova, Diplotheca tricyclica, foi registrada na área do canal principal do estuário, no verão de 1999, em águas de alta salinidade. Abstract in english The biodiversity of marine heterotrophic protists is poorly known in the South Atlantic coastal zone (~32 °S) especially regarding the nanoflagellates. The presence of loricate choanoflagellates was reported for the first time in the Patos Lagoon estuary and the adjacent coastal zone. Seventeen species of eleven genera of loricate choanoflagellates were observed between October 1998 and May 2000 in fixed water samples (lugol's solution + glutaraldehyde) in a JEM 100-SX t (more) ransmission electron microscope. Most species were recorded in euhaline and mixopolyhaline waters during the spring and summer, none in autumn and a few (four) in winter. The absence of choanoflagellates at the more sheltered inshore stations is due freshwater influence, and at the beach station, probably due the strong wave action. The probably cosmopolitan species Pleurasiga minima, Cosmoeca norvegica, C. ventricosa and Parvicorbicula circularis were present in spring or summer in the estuary channel and coastal area while Stephanoeca diplocostata which apparently prefers lower temperature, was recorded in winter. Calotheca alata and Campyloacantha spinifera are mainly temperate species and were present in spring. The new species Diplotheca tricyclica was recorded at the estuary channel in the summer 1999, in high salinity water.

Bergesch, Marli; Odebrecht, Clarisse; Moestrup, Øjvind

2008-12-01

346

Adaptive Parallel Tempering for Stochastic Maximum Likelihood Learning of RBMs  

CERN Multimedia

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

Desjardins, Guillaume; Bengio, Yoshua

2010-01-01

347

Photosynthesis in submersed macrophytes of a temperate lake  

Energy Technology Data Exchange (ETDEWEB)

The photosynthetic carbon fixation pathways and levels of carbon-fixing enzymes of four dominant submersed macrophytes of Lawrence Lake, southern Michigan, were investigated during the main growth season (May to November). All four species (Scirpus subterminalis Torr., Najas flexilis (Willd.) Rostk. and Schmidt, Potamogeton praelongus Wulf., and Myriophyllum heterophyllum Michx.) were C/sub 3/ plants based on their patterns of /sup 14/C pulse-chase incorporation. High levels of phosphoenolypyruvate carboxylase were also found in these species. These levels, as well as the ribulose 1,5-biphosphate carboxylase/phosphoenolpyruvate carboxylase ratio of the leaves, varied throughout the growing season and exhibited highest values in July. No shift in carbon fixation pathways, however, could be detected from July to October. The possible functions of phosphoenolypyruvate carboxylase in these plants, as well as the significance of C/sub 3/ metabolism in submersed plants of temperate lakes, are delineated.

Beer, S.; Wetzel, R.G.

1982-08-01

348

Antarctic, Sub-Antarctic and cold temperate echinoid database.  

Science.gov (United States)

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. PMID:22787419

Pierrat, Benjamin; Saucède, Thomas; Festeau, Alain; David, Bruno

2012-06-25

349

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; Thomas Saucède; Alain Festeau; Bruno David

2012-01-01

350

Antarctic, Sub-Antarctic and cold temperate echinoid database  

Science.gov (United States)

Abstract 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.

Pierrat, Benjamin; Saucede, Thomas; Festeau, Alain; David, Bruno

2012-01-01

351

Antarctic, Sub-Antarctic and cold temperate echinoid database.  

UK PubMed Central (United Kingdom)

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.

Pierrat B; Saucède T; Festeau A; David B

2012-01-01

352

A potential perennial host for Pseudoperonospora cubensis in temperate regions  

UK PubMed Central (United Kingdom)

Pseudoperonospora cubensis causes great losses in cucurbitaceous crops worldwide. In cool temperate climates of northern Europe or North America overwintering as active mycelium is not possible, because all hosts so far reported there are summer annuals. Oospores have not yet been found in these regions under field conditions. The only perennial member of the Cucurbitaceae found naturally in central and northern Europe is Bryonia dioica. To date this plant has not been recorded as a host for downy mildews, but our infection trials demonstrate that P. cubensis is able to infest this plant. Amplification and sequencing of the ITS rDNA confirmed the observed downy mildew disease on B. dioica as P. cubensis. From these findings, the possibility that P. cubensis may be able to overwinter on this perennial host cannot be excluded. Whether or not B. dioica plays a part in the epidemology of P. cubensis in Europe requires evaluation by further studies.

Runge Fabian; Thines Marco

2009-04-01

353

Environmental forcing on jellyfish communities in a small temperate estuary.  

Science.gov (United States)

The impact of biological, hydrodynamic and large scale climatic variables on the jellyfish community of Mondego estuary was evaluated from 2003 to 2010. Plankton samples were collected at the downstream part of the estuary. Siphonophora Muggiaea atlantica and Diphyes spp. were the main jellyfish species. Jellyfish density was generally higher in summer and since 2005 densities had increased. Summer community analysis pointed out Acartia clausi, estuarine temperature and salinity as the main driven forces for the assemblage's structure. Also, Chl a, estuarine salinity, runoff and SST were identified as the major environmental factors influencing the siphonophores summer interannual variability. Temperature influenced directly and indirectly the community and fluctuation of jellyfish blooms in the Mondego estuary. This study represents a contribution to a better knowledge of the gelatinous plankton communities in small temperate estuaries. PMID:22770533

Primo, Ana Lígia; Marques, Sónia C; Falcão, Joana; Crespo, Daniel; Pardal, Miguel A; Azeiteiro, Ulisses M

2012-06-23

354

Gene expression in the Streptomyces temperate phage phi C31.  

UK PubMed Central (United Kingdom)

The repressor gene, c, of the temperate Streptomyces phage, phi C31 was previously cloned and sequenced, and predicted to encode a 74-kDa protein. The c gene actually produces three in-frame, N-terminally different, C-terminally identical proteins of 74, 54 and 42 kDa. The repressor proteins are translated from a corresponding nest of transcripts. Genetic and biochemical evidence suggests that the transcription of the c locus is autoregulated possibly by the 42-kDa protein binding to a highly conserved 16-bp perfect inverted repeat. The 16-bp sequence is present at at least twelve loci throughout the phi C31 genome. Transcription of the 'early' region is complex, possibly involving phage-specific promoters. The phi C31 terminators display sequence conservation and may be regulated. The phi C31 gene 'k' may encode a nucleotide kinase-encoding gene.

Smith MC; Ingham CJ; Owen CE; Wood NT

1992-06-01

355

Photosynthesis in submersed macrophytes of a temperate lake  

International Nuclear Information System (INIS)

[en] The photosynthetic carbon fixation pathways and levels of carbon-fixing enzymes of four dominant submersed macrophytes of Lawrence Lake, southern Michigan, were investigated during the main growth season (May to November). All four species (Scirpus subterminalis Torr., Najas flexilis (Willd.) Rostk. and Schmidt, Potamogeton praelongus Wulf., and Myriophyllum heterophyllum Michx.) were C3 plants based on their patterns of 14C pulse-chase incorporation. High levels of phosphoenolypyruvate carboxylase were also found in these species. These levels, as well as the ribulose 1,5-biphosphate carboxylase/phosphoenolpyruvate carboxylase ratio of the leaves, varied throughout the growing season and exhibited highest values in July. No shift in carbon fixation pathways, however, could be detected from July to October. The possible functions of phosphoenolypyruvate carboxylase in these plants, as well as the significance of C3 metabolism in submersed plants of temperate lakes, are delineated

1982-01-01

356

Influence of titanium on the tempering structure of austenitic steels  

International Nuclear Information System (INIS)

[en] 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

1985-01-01

357

Environmental forcing on jellyfish communities in a small temperate estuary.  

UK PubMed Central (United Kingdom)

The impact of biological, hydrodynamic and large scale climatic variables on the jellyfish community of Mondego estuary was evaluated from 2003 to 2010. Plankton samples were collected at the downstream part of the estuary. Siphonophora Muggiaea atlantica and Diphyes spp. were the main jellyfish species. Jellyfish density was generally higher in summer and since 2005 densities had increased. Summer community analysis pointed out Acartia clausi, estuarine temperature and salinity as the main driven forces for the assemblage's structure. Also, Chl a, estuarine salinity, runoff and SST were identified as the major environmental factors influencing the siphonophores summer interannual variability. Temperature influenced directly and indirectly the community and fluctuation of jellyfish blooms in the Mondego estuary. This study represents a contribution to a better knowledge of the gelatinous plankton communities in small temperate estuaries.

Primo AL; Marques SC; Falcão J; Crespo D; Pardal MA; Azeiteiro UM

2012-08-01

358

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; Carlos Alberto Della Rovere; José Mario de Aquino; Sebastião Elias Kuri

2010-01-01

359

Anthropogenic impact on biogenic Si pools in temperate soils  

Directory of Open Access Journals (Sweden)

Full Text Available Human land use changes directly affect silica (Si) mobilisation and Si storage in terrestrial ecosystems and influence Si export from the continents, although the magnitudes of the impact are unknown. Yet biogenic silica (BSi) in soils is an understudied aspect. We have quantified and compared total biogenic (PSia) and easily soluble (PSie) Si pools at four sites along a gradient of disturbance in southern Sweden. An estimate of the magnitude of change in temperate continental BSi pools due to human disturbance is provided. Land use clearly affects BSi pools and their distribution. Total PSia and PSie for a continuous forested site at Siggaboda Nature Reserve (66 900 ± 22 800 kg SiO2 ha?1 and 952 ± 16 kg SiO2 ha?1) are significantly higher than disturbed land use types from the Råshult Culture Reserve including arable land (28 800 ± 7200 kg SiO2 ha?1 and 239 ± 91 kg SiO2 ha?1), pasture sites (27 300 ± 5980 kg SiO2 ha?1 and 370 ± 129 kg SiO2 ha?1) and grazed forest (23 600 ± 6370 kg SiO2 ha?1 and 346 ± 123 kg SiO2 ha?1). Vertical PSia and PSie profiles show significant (pa in disturbed soils. In temperate regions, total PSia showed a 10 % decline since agricultural development (3000BCE). Recent agricultural expansion (after 1700CE) has resulted in an average export of 1.1 ± 0.8 Tmol Si yr?1, leading to an annual contribution of ca. 20 % to the global land-ocean Si flux carried by rivers. Human activities clearly exert a long-term influence on Si cycling in soils and contribute significantly to the land-ocean Si flux.

W. Clymans; E. Struyf; G. Govers; F. Vandevenne; D. J. Conley

2011-01-01

360

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 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.

2012-01-01

 
 
 
 
361

Carbon concentration variability of 10 Chinese temperate tree species  

UK PubMed Central (United Kingdom)

A mass-based carbon (C) concentration ([C]) of 50% in dry wood is widely accepted as a constant factor for conversion of biomass to C stock. However, the [C] varies with tree species, and few data on [C] are available for the Chinese temperate tree species. In this study, we examined inter- and intra-specific variations of [C] in biomass tissues for 10 co-occurring temperate tree species in northeastern China. The species were Korean pine (Pinus koraiensis Sieb. et Zucc.), Dahurian larch (Larix gmelinii Rupr.), Mongolian oak (Quercus mongolica Fisch.), white birch (Betula platyphylla Suk.), Amur cork-tree (Phellodendron amurense Rupr.), Manchurian walnut (Juglans mandshurica Maxim.), Manchurian ash (Fraxinus mandshurica Rupr.), aspen (Populous davidiana Dode), Mono maple (Acer mono Maxim.), and Amur linden (Tilia amurensis Rupr.). The mean tissue [C] across the species varied from 47.1% in fine root to 51.4% in foliage. The mean stem [C] of the 10 species was 49.9±1.3% (mean±SE). The weighted mean C concentration (WMCC) for the species ranked as: Amur cork-tree (55.1%)>Amur linden (53.9%)>Korean pine (53.2%)>Manchurian ash (52.9%)>Manchurian walnut (52.4%)>Mongolian oak (47.6%)>Dahurian larch (46.9%)>Mono maple (46.4%)>white birch (46.1%)>aspen (43.7%). The WMCC of the dominant trees was negatively correlated to mean annual increment of biomass (MAI), suggesting that planting fast-growing tree species for C sequestration in afforestation and reforestation practices sacrifice some C gain from increasing MAI due to decreasing [C]. Failing to account for the inter- and intra-specific variations in [C] will introduce a relative error of -6.7% to +7.2% in estimates of biomass C stock from inventory data, of which >93% is attributed to ignoring the inter-specific variation in [C].

Zhang Quanzhi; Wang Chuankuan; Wang Xingchang; Quan Xiankui

2009-08-01

362

Productivity of some winter wheat genotypes  

Directory of Open Access Journals (Sweden)

Full Text Available Yields given by different genotypes are affected by many factors, but mostly by genotype, climatic conditions and applied growing practice. Therefore, the aim of this study was to establish productivity of many winter wheat genotypes in southern Serbia, through macro-trials. The results showed the difference of grain yield mean between the investigated seasons, and that difference amounted about 1300 kg/ha. The average yield was the highest in cultivars Toplica, Stamena, Evropa, NS-rana 5, and Renesansa. The lowest grain yield was given by cultivars Tina, Sara, Sre?a, and Mina.

Biberdži? Milan; ?or?evi? Midrag; Bara? Saša; Deleti? Nebojša; Stojkovi? Slaviša

2005-01-01

363

Solar heated building designs for cloudy winters  

UK PubMed Central (United Kingdom)

A building including high efficiency transparent insulation and optical shutter solar collector (HETIOSSC) to effectively control heat loss and gain in a passively-solar climate control system. HETIOSSC includes a layer of protective glazing, a transparent insulation, an optical shutter, an optional solar radiation absorbing material and optional heat storage elements. When the building and its heat storage are too warm, the optical shutter layer becomes opaque to prevent overheating. During cloudy and cold winter days, HETIOSSC still has a solar transmission and insulation efficiency great enough to collect sufficient sunlight for heating. Location of HETIOSSC on the roof, rather than the walls, does not alter shape and orientation of a building.

CHAHROUDI DAY

364

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

Science.gov (United States)

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

García, Ileana V; Mendoza, Rodolfo E

2008-01-17

365

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

UK PubMed Central (United Kingdom)

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

García IV; Mendoza RE

2008-03-01

366

Cantor dust zone plates.  

UK PubMed Central (United Kingdom)

In this paper we use the Cantor Dust to design zone plates based on a two-dimensional fractal for the first time. The pupil function that defines the coined Cantor Dust Zone Plates (CDZPs) can be written as a combination of rectangle functions. Thus CDZPs can be considered as photon sieves with rectangular holes. The axial irradiances produced by CDZPs of different fractal orders are obtained analitically and experimentally, analyzing the influence of the fractality. The transverse irradiance patterns generated by this kind of zone plates has been also investigated.

Ferrando V; Calatayud A; Giménez F; Furlan WD; Monsoriu JA

2013-02-01

367

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

UK PubMed Central (United Kingdom)

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.

Krawczyk J; Ba?a P; Pacyna J

2010-03-01

368

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

369

Winter precipitation isotope slopes of the contiguous USA and their relationship to the Pacific/North American (PNA) pattern  

Science.gov (United States)

This study compares the synoptic-dynamic relationship between two phases of the Pacific/North American (PNA) pattern and winter precipitation isotopes at 73 sites across the contiguous USA. We use the spatial pattern of isotope slope—the rate of changes in precipitation isotope ratios with distance—to identify features in the seasonal precipitation isotope fields related to climatic patterns, PNA positive and PNA negative. Our results show relationships between zones of high isotope slopes and the spatial position of the polar jet stream and juxtaposition of air masses associated with the PNA pattern. During a positive PNA winter, zones of high isotope slope in the eastern USA shift southward. This change is coincident with a southward displacement of the polar jet stream in this region, which leads to a greater frequency of polar air masses and 18O-depleted isotope values of precipitation in the region. In the western USA, zones of high slope shift eastward during the positive PNA winter, associated with more frequent penetration of tropical air masses that bring 18O-enriched precipitation to the region. Differences in ?18O/temperature relationships between the PNA-positive and -negative winters and contrasting ?18O/temperature behaviors in the eastern and western USA provide support for the role of variation in moisture source and transport as a control on the isotopic patterns. These findings highlight the importance of synoptic climate driven by PNA pattern in determining the spatial patterns of precipitation isotopes and provide constraints on paleo-water isotope interpretation and modern isotope hydrological processes.

Liu, Zhongfang; Bowen, Gabriel J.; Welker, Jeffrey M.; Yoshimura, Kei

2013-07-01

370

Tropical freshwater ecosystems have lower bacterial growth efficiency than temperate ones.  

UK PubMed Central (United Kingdom)

Current models and observations indicate that bacterial respiration should increase and growth efficiency (BGE) should decrease with increasing temperatures. However, these models and observations are mostly derived from data collected in temperate regions, and the tropics are under-represented. The aim of this work was to compare bacterial metabolism, namely bacterial production (BP) and respiration (BR), bacterial growth efficiency (BGE) and bacterial carbon demand (BCD) between tropical and temperate ecosystems via a literature review and using unpublished data. We hypothesized that (1) tropical ecosystems have higher metabolism than temperate ones and, (2) that BGE is lower in tropical relative to temperate ecosystems. We collected a total of 498 coupled BP and BR observations (N total = 498; N temperate = 301; N tropical = 197), calculated BGE (BP/(BP+BR)) and BCD (BP+BR) for each case and examined patterns using a model II regression analysis and compared each parameter between the two regions using non-parametric Mann-Whitney U test. We observed a significant positive linear regression between BR and BP for the whole dataset, and also for tropical and temperate data separately. We found that BP, BR and BCD were higher in the tropics, but BGE was lower compared to temperate regions. Also, BR rates per BP unit were at least two fold higher in the tropics than in temperate ecosystems. We argue that higher temperature, nutrient limitation, and light exposure all contribute to lower BGE in the tropics, mediated through effects on thermodynamics, substrate stoichiometry, nutrient availability and interactions with photochemically produced compounds. More efforts are needed in this study area in the tropics, but our work indicates that bottom-up (nutrient availability and resource stoichiometry) and top-down (grazer pressure) processes, coupled with thermodynamic constraints, might contribute to the lower BGE in the tropics relative to temperate regions.

Amado AM; Meirelles-Pereira F; Vidal LO; Sarmento H; Suhett AL; Farjalla VF; Cotner JB; Roland F

2013-01-01

371

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

Directory of Open Access Journals (Sweden)

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

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

2009-01-01

372

Forage radish winter cover crop suppresses winter annual weeds in fall and before corn planting  

Science.gov (United States)

Forage radish (Raphanus sativus L. var. longipinnatus) is a new winter cover crop in the Mid-Atlantic region. The objective of this project was to characterize the repeatability, amount, and duration of weed suppression during and after a fall-planted forage radish cover crop and to quantify the sub...

373

Energy exchange and evapotranspiration over two temperate semi-arid grasslands in North America  

UK PubMed Central (United Kingdom)

The seasonal and interannual variability in surface energy exchange and evapotranspiration (E) of two temperate semi-arid grasslands in southeastern Arizona, USA, were investigated using multi-year (2004–2007) eddy covariance measurements. The study sites, a post-fire site (AG) and an unburned site (KG), received 43–87% of the annual precipitation (P) during the North American Monsoon season (July–September), with the lowest values in the drought years of 2004 and 2005. Irrespective of the differences in temperature, surface albedo, vegetation cover and soil characteristics both sites responded similarly to changes in environmental conditions. The seasonal and interannual variations in the partitioning of net radiation to turbulent fluxes were mainly controlled by P through the changes in soil water content (?) and vegetation growth. Drastic changes in albedo, vegetation growth and energy fluxes occurred following the onset of the monsoon season in July. During the dry or cool periods of autumn, winter and spring, the sensible heat flux was the largest component of the energy balance, whereas latent heat flux dominated during the warm and wet periods of summer. The dry-foliage Priestley–Taylor coefficient (?) declined when ? in the 0–15cm soil layer dropped below 0.08m3m?3 at AG, and 0.09m3m?3 at KG, respectively. The July–September average of dry-foliage surface conductance, ? and E, reached their lowest values in 2004 at AG and in 2005 at KG. During July–September, monthly E was linearly correlated to the monthly mean ? and the broadband normalized difference vegetation index (NDVI), whereas during May–June the relationship between NDVI and E was not significant. Annual E varied from 264 to 322mm at AG and from 196 to 284mm at KG with the lowest value during the severe drought year at the site. July–September E had positive correlation with total P, the mean NDVI and the number of growing season days during that period. Annual P explained more than 80% of the variance in annual E.

Krishnan P; Meyers TP; Scott RL; Kennedy L; Heuer M

2012-02-01

374

Monitoring soil respiration using an automatic operating chamber in a Gwangneung temperate deciduous forest  

Directory of Open Access Journals (Sweden)

Full Text Available This study was conducted to quantify soil CO2 efflux using the continuous measurement method and to examine the applicabilityof an automatic continuous measurement system in a Korean deciduous broad-leaved forest. Soil respirationrate (Rs) was assessed through continuous measurements during the 2004-2005 full growing seasons using an automaticopening/closing chamber system in sections of a Gwangneung temperate deciduous forest, Korea. The study site was anold-growth natural mixed deciduous forest approximately 80 years old. For each full growth season, the annual Rs, whichhad a gap that was filled with data using an exponential function derived from soil temperature (Ts) at 5-cm depth, andRs values collected in each season were 2,738.1 g CO2 m-2 y-1 in 2004 and 3,355.1 g CO2 m-2 y-1 in 2005. However, the diurnalvariation in Rs showed stronger correlations with Ts (r = 0.91, P < 0.001 in 2004, r = 0.87, P < 0.001 in 2005) and air temperature(Ta) (r = 0.84, P < 0.001 in 2004, r = 0.79, P < 0.001 in 2005) than with deep Ts during the spring season. However,the temperature functions derived from the Ts at various depths of 0, -2, -5, -10, and -20 cm revealed that the correlationcoefficient decreased with increasing soil depth in the spring season, whereas it increased in the summer. Rs showed aweak correlation with precipitation (r = 0.25, P < 0.01) and soil water content (r = 0.28, P < 0.05). Additionally, the diurnalchange in Rs revealed a higher correlation with Ta than that of Ts. The Q10 values from spring to winter were calculatedfrom each season’s dataset and were 3.2, 1.5, 7.4, and 2.7 in 2004 and 6.0, 3.1, 3.0, and 2.6 in 2005; thus, showing high fluctuationwithin each season. The applicability of an automatic continuous system was demonstrated for collecting a highresolution soil CO2 efflux dataset under various environmental conditions.

Jae-Seok Lee*

2011-01-01

375

Seed Priming of Winter Annual Cover Crops Improves Germination and Emergence  

UK PubMed Central (United Kingdom)

Enhancing soil-protecting living cover over the winter is an important challenge in temperate row crop production. This note reports on novel findings for cover crop seed priming, a process of controlled hydration and drying. The effects of seed priming over durations of 0, 2, 4, 8, 12, 24, and 36 h were evaluated for four species that varied in seed size and germination characteristics: cereal rye (Secale cereale L.), perennial ryegrass (Lolium perenne L.), hairy vetch (Vicia villosa Roth), and oriental mustard (Brassica juncea L.). A logistic function modeled response was used to quantify onset of germination, time to 50% germination (t50), maximum germination rate, final germination percentage (K), seedling emergence, and establishment in laboratory germination paper and soil core assays. Rye seed germinated rapidly regardless of priming treatment. Under the optimum environmental conditions of a laboratory germination assay, the smallest seeded cover crop, perennial ryegrass, was the only species to show a final germination response that was higher in primed (86%) than untreated seed (78%). However, seed germination rates of three species were influenced by priming: 50% germination was reached 8, 6, and 9 h earlier in hairy vetch, mustard, and perennial ryegrass, respectively. Compacted soil assays showed that priming (24 h) improved seedling emergence by 36% and 57% for hairy vetch and perennial ryegrass, respectively, compared with untreated seed. These results were consistent across experiment runs. Seed priming shows promise as a new technology for improving cover crop establishment in compacted soil.

Snapp Sieglinde; Price Richard; Morton Maureen

2008-09-01

376