Search results for "ta119"

Study of Proton and 3He Induced Reactions on 235U at Low Energies

2014

Abstract Highly enriched 235 U targets were irradiated with 6.5 − 16.1 MeV protons and 20.4 − 42.0 MeV 3 He ions. The irradiated targets were measured with γ and α spectrometric methods to identify and quantify the produced reaction products. After primary activity measurements the targets were dissolved, and interesting Pu and Np reaction products were chemically separated from the target material, and measured for activity again. From the activity results it was possible to calculate the reaction cross sections for differently produced nuclides. The data obtained from the experiment resulted in earlier unknown excitation functions on proton and 3 He induced nuclear reactions on 235 U.

The precautionary principle and management of uncertainties in EIAs – analysis of waste incineration cases in Finland

2013

This article examines whether and how the practice of environmental impact assessments (EIAs) serves the idea of the precautionary principle. The article provides an empirical examination and description of how uncertainties and risks were dealt with in conclusive outputs of EIAs of chosen example cases of Finnish waste incineration projects. The analysis focuses on the time when several incineration projects were in the planning phase in Finland and the effects of this development were seen as being controversial. The findings of the analysis are evaluated against a legislative and theoretical framework. The challenges and strengths of the practice are identified. The article suggests that…

Different sensitivities of whitefish (Coregonus lavaretus) and northern pike (Esox lucius) eleutheroembryos to photoinduced toxicity of polycyclic ar…

2011

The photoinduced toxicity of two polycyclic aromatic hydrocarbons (PAHs), retene (RET) and pyrene (PYR), to the eleutheroembryos of whitefish and northern pike was studied. Fish were exposed to three concentrations of RET and PYR, and irradiated with ultraviolet radiation (UVR) or visible light for 3 h on two consecutive days. UVR covered the absorption maxima of RET and PYR at UVB and UVA, the daily UVR doses were 30 and 28 kJ m−2, respectively. After 72 h, mortality and behavioral abnormalities were observed. Survivors were analyzed for the proteins of CYP1A, CYP3A, Hsp70, and the activity of glutathione reductase (GR). While neither PAHs nor UVR on their own were lethal, simultaneous exp…

A case study of a precision fertilizer application task generation for wheat based on classified hyperspectral data from UAV combined with farm histo…

2013

Different remote sensing methods for detecting variations in agricultural fields have been studied in last two decades. There are already existing systems for planning and applying e.g. nitrogen fertilizers to the cereal crop fields. However, there are disadvantages such as high costs, adaptability, reliability, resolution aspects and final products dissemination. With an unmanned aerial vehicle (UAV) based airborne methods, data collection can be performed cost-efficiently with desired spatial and temporal resolutions, below clouds and under diverse weather conditions. A new Fabry-Perot interferometer based hyperspectral imaging technology implemented in an UAV has been introduced. In this…

Growth of domesticated discusSymphysodonsp. at constant temperatures

2012

Lipid-rich zooplankton subsidise the winter diet of benthivorous Arctic charr (Salvelinus alpinus) in a subarctic lake

2013

Summary Generalist fish species commonly act as important links between littoral and pelagic habitats and food-web compartments in lakes. However, diet and habitat links may depend significantly on seasonal availability of, and qualitative differences between, littoral and pelagic prey and on fish size. Despite increasing interest in food-web dynamics, little is known about the seasonal changes in, or qualitative differences between, littoral and pelagic trophic pathways supporting generalist fish species in high-latitude lakes. We used stomach contents together with analyses of stable carbon and nitrogen isotopes and fatty acids to study the winter and summer diet of generalist Arctic char…

Interlake variation and environmental controls of denitrification across different geographical scales

2013

Denitrification in lakes significantly reduces the nitrogen (N) load from land to oceans, but the factors controlling it remain poorly under- stood. Therefore, interlake variation of denitrification in sediments of small to medium-sized lakes (from 0.03 to 17.8 km 2 ) was studied across different geo- graphical scales. At the local scale, the denitrification rates and sediment microbial communities were studied in 4 boreal lakes in close proximity (within 20 km) using the isotope pairing technique (IPT) and molecular methods. These local scale data were com- bined with previously published data on denitrifica- tion rates from 10 other European lakes to extend the analysis to the regional (b…

Natural recruitment contributes to high densities of grass carp Ctenopharyngodon idella (Valenciennes, 1844) in Western Europe

2015

Introductions of grass carp, well known for their potentially negative ecosystem effects, have been performed in several countries around the world. As the species was considered unable to reproduce naturally under non-native environmental conditions, little attention was initially given to its invasive potential. We studied an area in northern-Italy where, contrary to expectations, introductions that were performed in the early 80s still exert a considerable pressure on aquatic macrophytes. In order to reveal whether the observed population dynamics are the result of natural events or stocking we analysed the density, age- and size-structure of the grass carp population and the migration p…

Hyperspectral imaging based biomass and nitrogen content estimations from light-weight UAV

2013

Hyperspectral imaging based precise fertilization is challenge in the northern Europe, because of the cloud conditions. In this paper we will introduce schemes for the biomass and nitrogen content estimations from hyperspectral images. In this research we used the Fabry-Perot interferometer based hypespectral imager that enables hyperspectral imaging from lightweight UAVs. During the summers 2011 and 2012 imaging and flight campaigns were carried out on the Finnish test field. Estimation mehtod uses features from linear and non-linear unmixing and vegetation indices. The results showed that the concept of small hyperspectral imager, UAV and data analysis is ready to operational use.