Publikasjoner
NIBIOs ansatte publiserer flere hundre vitenskapelige artikler og forskningsrapporter hvert år. Her finner du referanser og lenker til publikasjoner og andre forsknings- og formidlingsaktiviteter. Samlingen oppdateres løpende med både nytt og historisk materiale. For mer informasjon om NIBIOs publikasjoner, besøk NIBIOs bibliotek.
2018
Sammendrag
This research note offers a critical-constructive discussion of the article ‘Class, Culture and Culinary Tastes: Cultural Distinctions and Social Class Divisions in Contemporary Norway’, written by Flemmen, Hjellbrekke and Jarness (FHJ) (Sociology, 2018(1)). Concerns are raised about the methods and the use of the data. A robustness analysis with alternative data and/or alternative methods is suggested. Conceptually, the analysis of FHJ is considered not to engage adequately with a more qualitative body of historical and ethnological literature, as well as the impact of Norwegian agricultural policy. To describe and understand the evolution of social meaning and social patterns of the consumption of ‘traditional’ Norwegian foodstuffs, a qualitative approach could have contributed constructively. Overall, wider implications for Bourdieu-inspired analyses of cultural consumption are addressed.
Sammendrag
The research literature on food selection by large herbivores is extensive. Still, we are generally lacking in our knowledge of the influence of potentially interacting chemical contents of the food. We made a qualitative review of a systematic literature search of studies that empirically link chemical contents of food to the food selection by northern cervids (genera Alces, Capreolus, Cervus, Dama, Odocoileus, Rangifer). We found that although the majority of the 98 relevant studies measuring any given food constituent (energy, protein, fiber, minerals, plant secondary metabolites) provided support for it acting as a driver of food selection (in either a negative or positive way), there was little support for the traditional hypotheses of maximization or limitation of any single constituent. Rather, because of the animals’ need to acquire an appropriate intake of several constituents at the same time, our review highlights how new empirical stud- ies need to focus on several food constituents in synchrony: (1) Study designs should capture sufficient variation in the content of food constituents in order to tease apart their many co-variations; and (2) insights about nutritional drivers may be lost if one uses only composite currencies such as crude energy, crude fiber, ash, or tannins, which may mask contrasting selection patterns of the lumped constituents. Season had an apparent influence on the selection of some food constituents, particularly various fiber frac- tions. In contrast, our review revealed a lack of evidence that cervids more strongly select for protein in summer than they do in winter. Our overall conclusion of the review is that interacting chemical contents of food make the nutritional value of a given food type into a varying entity. To better elucidate this varia- tion, we need new technologies that non-invasively capture nutrient intake of free-ranging animals, across seasons.
Forfattere
Magdalena Z. Bieroza A. Louise Heathwaite Marianne Bechmann Katarina Kyllmar Philip JordanSammendrag
Recent technological breakthroughs of optical sensors and analysers have enabled matching the water quality measurement interval to the time scales of stream flow changes and led to an improved understanding of spatially and temporally heterogeneous sources and delivery pathways for many solutes and particulates. This new ability to match the chemograph with the hydrograph has promoted renewed interest in the concentration-discharge (c-q) relationship and its value in characterizing catchment storage, time lags and legacy effects for both weathering products and anthropogenic pollutants. In this paper we evaluated the stream c-q relationships for a number of water quality determinands (phosphorus, suspended sediments, nitrogen) in intensively managed agricultural catchments based on both high-frequency (sub-hourly) and long-term low-frequency (fortnightly-monthly) routine monitoring data. We used resampled high-frequency data to test the uncertainty in water quality parameters (e.g. mean, 95th percentile and load) derived from low-frequency sub-datasets. We showed that the uncertainty in water quality parameters increases with reduced sampling frequency as a function of the c-q slope. We also showed that different sources and delivery pathways control c-q relationship for different solutes and particulates. Secondly, we evaluated the variation in c-q slopes derived from the long-term low-frequency data for different determinands and catchments and showed strong chemostatic behaviour for phosphorus and nitrogen due to saturation and agricultural legacy effects. The c-q slope analysis can provide an effective tool to evaluate the current monitoring networks and the effectiveness of water management interventions. This research highlights how improved understanding of solute and particulate dynamics obtained with optical sensors and analysers can be used to understand patterns in long-term water quality time series, reduce the uncertainty in the monitoring data and to manage eutrophication in agricultural catchments.
Forfattere
Habtamu AlemSammendrag
Previous studies estimating TFP and its components have been criticized for not considering farm heterogeneity in their model. Moreover, the studies focused on the technical evaluation of a sector. However, the technical evaluation alone reveals how well farmers use the physical production process. There is a need to closely examine the cost efficiency of the farmers. In this study, we used a cost function (dual) approach to facilitating the decomposition and estimation of TFP components. Using a translog stochastic cost function, we estimated the level and source of productivity and profitability change for crop producing family firms in Norway. We used the true random effect to account for farm heterogeneity. The analysis is based on 23 years unbalanced panel data (1991-2013) from 455 crop- producing firms with a total of 3885 observations. The result indicates that average annual productivity growth rate in grain and forage production was - 0.11 % per annum during the period 1991-2013. The profit change was 0.14 % per annum.
Forfattere
Habtamu AlemSammendrag
Previous studies estimating TFP and its components have been criticized for not considering farm heterogeneity in their model. Moreover, the studies focused on the technical evaluation of a sector. However, the technical evaluation alone reveals how well farmers use the physical production process. There is a need to closely examine the cost efficiency of the farmers. In this study, we used a cost function (dual) approach to facilitating the decomposition and estimation of TFP components. Using a translog stochastic cost function, we estimated the level and source of productivity and profitability change for crop producing family firms in Norway. We used the true random effect to account for farm heterogeneity. The analysis is based on 23 years unbalanced panel data (1991-2013) from 455 crop- producing firms with a total of 3885 observations. The result indicates that average annual productivity growth rate in grain and forage production was - 0.11 % per annum during the period 1991-2013. The profit change was 0.14 % per annum.
Forfattere
Habtamu AlemSammendrag
This doctoral thesis incorporates an integrated framework for the measurement and analysis of the performance of Norwegian farms, focusing on crop-producing and dairy farms. Farm-level datasets were used in the analysis. The thesis comprises an introductory chapter and five independent research articles. The aim of the first article is to explore the effects of model specifications and estimate short-run and long-run inefficiency. We used the transcendental logarithmic (translog) cost function and the analysis is based on unbalanced farm-level panel data for the period 1991–2013 from 455 Norwegian farms that specialise in crop production in the Eastern and Central regions of Norway. It was found that cost efficiency scores are sensitive to how the inefficiency is modelled and interpreted. Empirical analysis demonstrates that the magnitude of long-run inefficiency (5%) is lower than the level of short-run inefficiency (6%). It would be possible to reduce crop production costs by, on average, up to 5% if shortfalls in managerial capabilities were reduced. Such shortfalls in farmers’ management abilities derive from such factors as lack of farming experience and lack of farm ownership. On the other hand, it would be possible to reduce crop production costs by up to 6% if transient inefficiencies could be eliminated. On average, actual costs could be reduced by 11% without reducing output if both forms of inefficiency were eliminated from Norwegian crop production. Policy interventions to this end might include providing training in farm-management practices, and policy changes to ease rigidity in farm ownership. The objective of the second article is to measure the economic performance of two crop-producing Norwegian farms while accounting for both unobserved heterogeneity and environmental variables. The analysis employs a translog cost function and is based on unbalanced farm-level panel data comprising 3,855 observations (1,004 observations from the central region and 2,884 from the eastern region). We found that the mean minimum costs for the period 1991–2013 were approximately 93% and 92% of the actual production costs for crop farms in the central and eastern regions, respectively. The marginal effects of crop rotation, land tenure, off-farm activity, direct government support, and experience positively correlated with the economic performance of crop farms. In both regions, the marginal contribution of these variables to economic performance increased for the period 2000–2013 compared to 1991–1999. The aim of Article 3 is to measure the contribution of productivity and price change to changes in the profitability of crop-producing family farms in Norway. The results indicate that the average annual productivity growth rate for grain and forage production decreased by 0.11% per annum over the period 1991–2013. Profits decreased by 0.14% per annum primarily due to the effect of the trend of increasing input prices and a decline in total factor productivity. Interventions to improve the productivity of farms would also improve farm profitability.
Sammendrag
Det er ikke registrert sammendrag
Sammendrag
Det er ikke registrert sammendrag
Forfattere
Dag Fjeld Oivind Østby-Berntsen Bruce TalbotSammendrag
Det er ikke registrert sammendrag
Forfattere
Bjørn ØklandSammendrag
Det er ikke registrert sammendrag