Englert M.,Institute of Applied Ecology |
Friess F.,TU Darmstadt |
Friess F.,University of Natural Resources and Life Sciences, Vienna |
Ramana M.V.,Princeton University
Science and Global Security | Year: 2017
Proponents of high temperature gas cooled reactors argue that the reactor type is inherently safe and that severe accidents with core damage and radioactive releases cannot occur. The argument is primarily based on the safety features of the special form of the fuel. This paper examines some of the assumptions underlying the safety case for high temperature gas cooled reactors and highlights ways in which there could be fuel failure even during normal operations of the reactor; these failures serve to create a radioactive inventory that could be released under accident conditions. It then describes the severe accident scenarios that are the greatest challenge to high temperature gas cooled reactor safety: ingress of air or water into the core. Then, the paper offers an overview of what could be learned from the experiences with high temperature gas cooled reactors that have been built; their operating history indicates differences between actual operations and theoretical behavior. Finally, the paper describes some of the multiple priorities that often drive reactor design, and how safety is compromised in the process of optimizing other priorities. © 2017 Taylor & Francis Group, LLC.
Hajkova P.,Masaryk University |
Hajkova P.,Academy of Sciences of the Czech Republic |
Hajkova P.,Czech Republic Crop Research Institute |
Grootjans A.,University of Groningen |
And 10 more authors.
Journal of Quaternary Science | Year: 2012
In general, mires develop by autogenic succession from more groundwater-fed to more rainwater-fed. This study from a calcareous mire in the West Carpathians (Slovakia) describes a similar development in the Early Holocene, followed by a reverse development in the Middle and Late Holocene. Pollen, macrofossil and testate amoeba analyses show that the site started as a minerotrophic open fen woodland. After 10 700 cal a BP autogenic succession led to the accumulation of at least 1m of Sphagnum fuscum peat. Around 9000 cal a BP, as climate could no longer sustain a stable water regime, the bog desiccated and a fire broke out. The fire removed part of the peat layer and as a consequence relative water levels rose, leading to the establishment of a wet minerotrophic swamp carr with Thelypteris palustris, Equisetum sp. and Alnus sp. with extremely slow peat accumulation. After 600 cal a BP, rapid peat accumulation with calcareous tufa formation resumed as a result of anthropogenic deforestation and hydrological changes in the catchment and resulting increased groundwater discharge. At present the mire still hosts a wealth of relict and endangered plant and animal species typical of calcareous fens and fen meadows. © 2011 John Wiley & Sons, Ltd.
Popovic V.,Serbian Institute of Field and Vegetable Crops |
Malesevic M.,Serbian Institute of Field and Vegetable Crops |
Drazic G.,Institute of Applied Ecology |
Spasic M.,Agromaster Company |
Stankovic S.,Technological Research Center
Genetika | Year: 2011
A three-year trial (2003-2005) was conducted under agro ecological conditions of Timočka Krajina (the experiment farm of Technological Research Center in Zaječar). Research object were six malting barley genotypes, which were top-dressed with the following amounts of nitrogen in the course of growing season: 40, 60, 80 and 100 kg ha-1. A non-fertilized variant served as a control. The obtained results indicated that the tested genotypes reacted to increased amounts of nitrogen by changing their morphological and biological characteristics as well as the technological values of grain. The effectiveness of the applied nitrogen depended significantly on the distribution of rainfall in periods of highest water uptake by malting barley.
Cizkova H.,University of South Bohemia |
Kvet J.,University of South Bohemia |
Comin F.A.,CSIC - Pyrenean Institute of Ecology |
Laiho R.,University of Helsinki |
And 2 more authors.
Aquatic Sciences | Year: 2013
The present area of European wetlands is only a fraction of their area before the start of large-scale human colonization of Europe. Many European wetlands have been exploited and managed for various purposes. Large wetland areas have been drained and reclaimed mainly for agriculture and establishment of human settlements. These threats to European wetlands persist. The main responses of European wetlands to ongoing climate change will vary according to wetland type and geographical location. Sea level rise will probably be the decisive factor affecting coastal wetlands, especially along the Atlantic coast. In the boreal part of Europe, increased temperatures will probably lead to increased annual evapotranspiration and lower organic matter accumulation in soil. The role of vast boreal wetlands as carbon sinks may thus be suppressed. In central and western Europe, the risk of floods may support the political will for ecosystem-unfriendly flood defence measures, which may threaten the hydrology of existing wetlands. Southern Europe will probably suffer most from water shortage, which may strengthen the competition for water resources between agriculture, industry and settlements on the one hand and nature conservancy, including wetland conservation, on the other. © 2011 Springer Basel AG.
Morbey Y.E.,University of Western Ontario |
Coppack T.,Institute of Applied Ecology |
Pulido F.,Complutense University of Madrid
Journal of Ornithology | Year: 2012
Our understanding of avian migration has progressed significantly, yet the selective conditions that favor the arrival of males before females at the site of reproduction remain largely unclear. Here, we review the leading adaptive hypotheses for protandry, highlight some key empirical studies that test protandry theory, and identify theoretical and empirical information demands. In general, protandry should evolve in species where the variance in male reproductive success is larger than in females if the costs to males of earlier arrival relative to calendar date (viability selection) can be balanced by increased mating opportunities (sexual selection). Early arrival by males can provide 'priority benefits' that help in the monopolization of resources or 'early bird draw benefits' that increase opportunities for extra-pair mating. While some empirical studies are consistent with theoretical predictions regarding the important selection factors that influence protandry (e. g., extrinsic mortality and extra-pair paternity), some are not, and some studies focus on ecological factors that have not been considered explicitly by theory. We call for an integrated theoretical approach to help formalize how protandry should evolve in response to the antagonistic roles of natural and sexual selection, the nature of competitive asymmetries among males or females, sex-specific costs and benefits of early arrival, and various climate change scenarios. © 2012 Dt. Ornithologen-Gesellschaft e.V.
Vlach P.,University of West Bohemia |
Svatora M.,Vinicna 7 |
Dusek J.,Institute of Applied Ecology
Knowledge and Management of Aquatic Ecosystems | Year: 2013
The diet and food niche overlap of five fish species in the Úpoř brook was evaluated. The supply of food represented by benthos was studied, and the proportion of total food particles in the intestine of brown trout Salmo trutta L., chub Squalius cephalus (L.), dace Leuciscus leuciscus (L.), bullhead Cottus gobio (L.) and stone loach Barbatula barbatula (L.) was measured. Evaluations were performed using a new index (Mtot p). All fish species except stone loach exhibited a balanced consumption of the food supply. The food components were systematically grouped, but no differences in the ingestion of these groups were found. However, a new approach in the evaluation of food competition based on observation of species-specific preferences/avoidance in ingestion of food particles was applied. The particles were divided into four ecological categories according to their availability for fish. Brown trout concentrated on easily accessible sources of benthos or that hiding below stones, and also distinctly preyed on terrestrial insects. Chub displayed a similar feeding habit, though concentrating more on drift and allochthonous sources. The food spectrum of dace was mostly composed of easily accessible benthic organisms, consuming fewer hidden benthos and terrestrial insects. The food of bullhead and stone loach was similar, both preferring benthos. Bullhead consumed hidden species while stone loach consumed more accessible species rather than hidden ones. © 2013 ONEMA.
Liu J.,Chinese Institute of Urban Environment |
Liu J.,University of Rostock |
Liu J.,University of Sheffield |
Kang J.,University of Sheffield |
And 3 more authors.
Landscape and Urban Planning | Year: 2013
Based on the loudness of different soundscape elements perceived on site, soundscapes were analysed in a multi-functional urban area in Rostock, Germany. The aim was to examine how urban soundscape composition changes spatiotemporally at different levels over a relatively large scale, and how soundscape perception is related to the underlying landscape. The results show that although anthropogenic sounds (anthrophony) dominated urban soundscape both spatially and temporally, certain biological sounds (biophony) and geophysical sounds (geophony), especially bird song, also played a significant role. Urban soundscapes showed diverse spatiotemporal patterns. Spatial variation of urban soundscape patterns was explained by underlying landscape characteristics, while temporal variation was mainly driven by urban activities, among which human activities were the major component. It is demonstrated that the thematic soundscape mapping techniques developed in this study is an effective tool. Landscape composition and configuration indicators could affect soundscape perception significantly, among which normalised difference vegetation index (NDVI) and landscape shape index (LSI) are the two most important predictors. The results highlight the importance of introducing more natural sounds into urban environments to achieve "noise control" through an ecological urban/landscape planning process. © 2013 Elsevier B.V.
Holusa J.,Czech University of Life Sciences |
Kocarek P.,University of Ostrava |
Marhoul P.,Institute of Applied Ecology |
Skokanova H.,Silva Tarouca Research Institute for Landscape and Ornamental Gardening
Journal of Insect Conservation | Year: 2012
The northwestern distributions of several steppe species of Orthoptera extend to the southeastern part of the Czech Republic (Pannonia) and occupy more or less isolated fragments of optimal habitats. Their distributional limits are not conditioned by macroclimate in most cases but reflect landscape development (physical structure, plant community type and microclimate) and the insects' dispersal abilities. These species prefer permanent grassland, and assessment of land use records indicates that the area occupied by permanent grassland has been greatly reduced by agriculture over the last two centuries. The area occupied by permanent grasslands in Pannonia was highest in the nineteenth century, declined until the second half of the twentieth century, and slightly increased at the beginning of the twenty first century. These changes in the area of permanent grassland generally reflect economic and political processes; in particular, consolidation of land plots and expropriation of private property brought an end to grazing. The distribution of a model Orthoptera specialist, Platycleis vittata, on steppe habitats was surveyed at 48 potentially suitable locations from 2004 to 2010. The survey determined that the area with suitable habitat is currently very limited at all 48 locations. Occurrence was confirmed in just two locations that are 3 km apart. The research suggests that Platycleis vittata in the Czech Republic is on the brink of extinction because of extreme fragmentation of suitable biotopes and degradation of optimal habitats. © 2012 Springer Science+Business Media B.V.
Konvalinkova P.,University of South Bohemia |
Konvalinkova P.,Academy of Sciences of the Czech Republic |
Konvalinkova P.,Institute of Applied Ecology |
Prach K.,University of South Bohemia |
Prach K.,Academy of Sciences of the Czech Republic
Preslia | Year: 2010
This study was conducted at 17 peatlands in the Czech Republic mined either by the traditional block-cut method or industrially. Phytosociological reléves of 5 × 5 m were carried out in representative parts of successional stages in disturbed peatlands. Age and environmental characteristics were assessed for each relevé (position of water table, water pH, substratum chemistry, geographical area) or each locality (altitude, average annual temperature and precipitation). Phytosociological reléves recorded in natural vegetation, representing the respective target stages, were included into some analyses. Altogether, 210 relevés were analysed by the DCA ordination. Separately, relevés from milled and block-cut sites were elaborated by CCA with marginal and partial effects calculated. Despite the great variability in vegetation, especially among industrially harvested sites, there is a general tendency for peatland vegetation to recover spontaneously, especially at traditionally harvested sites, which all were, however, older than 50 years. The vegetation at the younger industrially harvested sites exhibited only a tendency to recover. All environmental variables investigated had at least some significant effect on the vegetation pattern, among them, soil pH, water table, nitrates, successional age and geographical location were most important. Abiotic site factors together and geographical location appeared to be more important in determining species composition than successional age.
Chi G.Y.,Institute of Applied Ecology |
Chi G.Y.,University of Chinese Academy of Sciences |
Chen X.,Institute of Applied Ecology |
Shi Y.,Institute of Applied Ecology
Advanced Science Letters | Year: 2011
Forestland, paddy field and upland field in Sanjiang Plain were studied. Soil samples were collected according to profile layers, and profile distribution of soil amorphous iron and total phosphorus and relationships with organic matter, pH as well as with moisture content were explored. Results showed that profile distribution of soil amorphous iron in paddy field and upland field increased comparing with the forestland, and soil amorphous iron in 0-40 cm layers of paddy field soils markedly higher than that of upland field. Soil total phosphorus below 20 cm layers increased in the sequence: forestland < paddy field < upland field, and which increased by 91.14% in paddy field and 200.92% in upland field below 90 cm, compared to forestland. Soil amorphous iron and total phosphorus both had significantly positively correlations with organic matter and moisture content. There were markedly negative correlations between soil amorphous iron and total phosphorus with pH. © 2011 American Scientific Publishers.