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.
2012
Forfattere
Sekhar Udaya Nagothu M. Muralidhar M. Kumaran B. Muniyandi R. Umesh K.S. Krishna Prasad Sena S. De SilvaSammendrag
Approximately 70% of shrimp consumed globally is farmed. India is ranked among the top five shrimp farming countries globally, and occurs mainly in the eastern coastal state of Andhra Pradesh (AP). More than 90% of the farms are less than 2 ha and are farmer owned, operated and managed. The objective of this study was to increase our understanding of climatic and socio-economic factors influencing this sector, through a survey of 300 shrimp farmers in AP in 2009/10. The farming communities were divisible into two groups: members of a society/cooperative and those operating individually. The latter were large scale adopting more intensive practices. The average production cost was Indian Rupees (IRS) 80,186 ha-1 and net income in summer and winter was IRS 221,901 and IRS 141,715, respectively. The mean technical efficiency estimated using Stochastic frontier function was 7% and 54%. The present study attempts to explain the difference in efficiencies using socio-economic and climatic variables, the latter being a novel approach. Among socio-economic variables, farming experience and membership in society were found to have a significant influence to improve technical and economic efficiencies. Further improvements in identifiable facets of the practices and a consequent increase in technical efficiency will make the sector less vulnerable to climatic change impacts.
Sammendrag
The aim of this experiment was to investigate the effect of increasing the number of ewes per nipple drinker on water intake, feed intake and drinking behaviour of ewes. A group of 30 1¾ year old, pregnant ewes of the Norwegian Dala breed were exposed to three treatments, each treatment lasting one week: 7.5 ewes per nipple drinker (N7.5: four nipple drinkers), 15 ewes per nipple drinker (N15: two nipple drinkers) and 30 ewes peer nipple drinker (N30: one nipple drinker). The experiment was performed both in January (week 4–6, replicate 1) and replicated in April (week 13–15, replicate 2). The ewes were kept in insulated building and had free access to good quality hay. Water metres were connected to the pipeline for water supply and water wastage was collected and weighed. In addition, the daily intake of hay was recorded and the ewes were video recorded the three last days of each experimental period. Total drinking time per individual was calculated from observations of drinking behaviour from the video, as were also incidents of queuing and displacements. Both water and feed intake was higher in replicate 2 than in replicate 1. Increasing the number of individuals per nipple drinker had no effect on water intake in replicate 1, whereas in replicate 2 the water intake was (mean±SE) 3.5±0.3; 4.2±0.1 and 4.9±0.1 l/ewe and day in the treatments N7.5, N15 and N30, respectively (P<0.05). Regardless of replicate, the time spent drinking increased significantly when number of ewes per nipple drinker increased. Queuing was not affected by increasing the number of ewes per nipple drinker. In replicate 1 the number of displacements increased significantly when the number of individuals per nipple drinker increased (N7.5=7.6±1.7; N15=15.0±4.2 and N30=36.7±5.2; P<0.05) and the same trend could be seen in replicate 2, although not significant. In conclusion, one nipple drinker with an acceptable flow rate can serve up to 30 ewes without negatively affecting water and feed intake
Sammendrag
The genera Leiopus Audinet-Serville, 1835 and Acanthocinus Dejean, 1821 are redescribed. New morphological differences at the generic level are described, and the importance of genitalia characters in taxonomy at both species and generic level is emphasized. Carinopus subgen. nov. in Leiopus is described from mainland China and Taiwan. Acanthobatesianus subgen. nov. in Acanthocinus is described from China, the Korean peninsula and Japan. Leiopus (Carinopus) campbelli (Gressitt, 1937) comb. nov. is transferred from Acanthocinus, and Acanthocinus (Acanthobatesianus) guttatus (Bates, 1873) comb. nov. from Leiopus. Six new species of Leiopus from China are diagnosed, described, and illustrated: L. nigropunctatus sp. nov., L. flavomaculatus sp. nov., L. ocellatus sp. nov., L. nigrofasciculosus sp. nov., L. holzschuhi sp. nov. and L. multipunctellus sp. nov. Redescriptions of L. kharazii Holzschuh, 1974, L. albivittis albivittis Kraatz, 1879, L. stillatus (Bates, 1884), L. (Carinopus) shibatai Hayashi, 1974, L. (Carinopus) fallaciosus Holzschuh, 1993, L. (Carinopus) campbelli (Gressitt, 1937) comb. nov. and Acanthocinus (Acanthobatesianus) guttatus (Bates, 1873) comb. nov. are added. A key to the generic and subgeneric levels of Leiopus and Acanthocinus, and a dichotomous key to all six new species of Carinopus subgen. nov. (Leiopus str.) from China, are provided.
Sammendrag
The relative frequency of Therrya fuckelii and T. pini fruiting on dead branches of Scots pine was investigated in southern Norway by examining lightning-damaged and wind-fallen trees, randomly collected branches and Nordic herbarium collections of these ascomycetes representing the order Rhytismatales. Ascus, ascospore, and subhymenium characteristics were used as criteria for species identification, while a sequence analysis of ITS rDNA gene cluster was performed to compare the relatedness of the species to each other and to corresponding fungal sequences available at the NCBI GenBank Sequence Database. In a few cases, the two Therrya species co-occurred on the same branch, but in general, whether field or herbarium material, T. fuckelii was clearly more common than T. pini.Within the Nordic countries, both species occurred throughout the natural distribution area of Scots pine. The ITS rDNA sequence of T. pini strains was 91% similar to T. fuckelii strains, the differences locating both within the internal transcribed spacers ITS1 and ITS2 and the 5.8 S rDNA gene. More variation in the ITS1-5.8S-ITS2 sequence was observed among T. pini than T. fuckelii samples; genetic implications of this finding are discussed. Upon sequence analysis, we discovered that a T. pini sequence has been deposited in the NCBI GenBank under a false identity. We emphasize the importance of co-examining strains that originate from mature fruit bodies with fully developed morphologic features as reference samples.
Forfattere
Kjell Andreassen Bernt-Håvard ØyenSammendrag
Thirteen Nordic stand growth models have been validated by use of a test data set from long-term research plots in Norway. The evaluated data was from time-series of even-aged, pure stands of Norway spruce, Scots pine and birch (silver birch and downy birch). In selected models from Finland, Norway and Sweden measures of site productivity, mean tree size and various stand characteristics are represented. Different models display both strengths and weaknesses in their predicting ability. Several measures of precision and bias have been calculated and the models are ranked due to their performance. We observed site quality, stand density and average tree size as the three main components in the models. Basal area increment model for spruce from Sweden had the lowest standard deviation with 23%. The mean R2 between residuals and stand characteristics from this model was also low (1.3%), which indicates that independent variables are well included. For Scots pine and birch, Finnish volume increment models showed the best fit to the Norwegian test data, with a R2 between residuals and stand characteristics of 2.8 and 6.7%, respectively. Several of the models from Sweden and Finland predicted the growth as well as stand models frequently in use in Norway. The results indicated that similar forest conditions and traditional even-aged forest management practice in the Nordic countries could be seen as a suitable basis for developing a joint family of growth models. By careful recalibration of existing models, a reasonable accuracy could be achieved and the prediction bias could be reduced.
Forfattere
Jozef Martinka Karol Balog Tomás Chrebet Emília Hroncová Janka DibdiakovaSammendrag
The presented article deals with the assessment of combined impact of temperature and flow of oxidising atmosphere, its oxygen concentration and heat flux on the ignition time of isotactic polypropylene (PP). The ignition time was determined in a specially adapted hot air Setchkin furnace at temperatures (450 and 600 °C), density of heat flux (12.4 and 26.4 kW m−2), flows of oxidation mixture (6 and 8 L min−1) and volume oxygen concentrations (3, 9, 15, 21, 27, 33, 39, 45 and 50 %). Obtained data allows us to assume that the temperature influence on PP induction period of ignition increases with decreasing flow rate of oxidising atmosphere. At the flow of oxidising mixture equal to 6 L min−1 and temperature of 600 °C, oxygen concentration had only a negligible impact on the the induction period of ignition in the analysed period. From the presented results, the induction period of ignition depends on the temperature and also on the flow rate of oxidising mixture and oxygen concentration in it. In addition, heat flux has a significant influence on the induction period. However, the quantification of the heat flux influence was not possible with the applied experimental device.
Forfattere
Stein Michael Tomter Patrizia Gasparini Thomas Gschwantner Petra Hennig Gintaras Kulbokas Andrius Kuliesis Heino Polley Nicolas Robert Jacques Rondeux Giovanni Tabacchi Erkki TomppoSammendrag
Estimates of growing stock in European countries vary mainly by using different thresholds for dbh of sample trees, as well as by the inclusion or exclusion of stump and stem top volume. European national forest inventories use dbh thresholds ranging from 0 to 12 cm in estimating the volume of growing stock. COST Action E43 has agreed to a reference definition for growing stock with a dbh threshold of 0 cm. With use of national volume distributions by dbh classes, models for estimating the proportions of growing stock between the national threshold and the 0-cm threshold were constructed. Models for characterizing growing stock distributions were tested, and their predictive abilities were investigated. Similar comparisons were made with respect to the volume of stumps and stem tops. Examples of estimation methods and the resulting percentages of these tree elements of total growing stock are presented.
Forfattere
Karsten Dunger Sven Hans-Olof Petersson Susana Barreiro Emil Cienciala Antoine Colin Gro Hylen Gal Kusar Katja Oehmichen Erkki Tomppo Tarja Tuomainen Göran StahlSammendrag
Most European countries have signed the United Nations Framework Convention on climate change and its Kyoto Protocol. Because the European Union is a party to the convention just like the individual countries, there is a need for harmonizing emissions reporting. This specifically applies to the Land Use, Land-Use Change, and Forestry sector, for which harmonized reporting is complex and generally challenging. For example, parties use a variety of different methods for estimating emissions and removals, ranging from application of default factors to advanced methods adapted to national circumstances, such as ongoing field inventories. In this study, we demonstrate that without harmonization, national definitions and methods lead to inconsistent estimates. Based on case studies in Finland, Germany, Norway, Portugal, Slovenia, and Sweden, we conclude that common reference definitions and country-specific bridges are means to harmonize the estimates and make greenhouse gas reporting from forests comparable across countries.
Forfattere
Karen Refsgaard Ingrid GuldvikSammendrag
Det er ikke registrert sammendrag
Forfattere
Anders Skonhoft Vebjørn Veiberg Asle Årthun Gauteplass Jon Olaf Olaussen Erling Meisingset Atle MysterudSammendrag
This paper presents a bioeconomic analysis of a red deer population within a Norwegian institutional context. This population is managed by a well-defined manager, typically consisting of many landowners operating in a cooperative manner, with the goal of maximizing the present-value hunting related income while taking browsing and grazing damages into account. The red deer population is structured in five categories of animals (calves, female and male yearlings, adult females and adult males). It is shown that differences in the per-animal meat values and survival rates (‘biological discounted’ values) are instrumental in determining the optimal harvest composition. Fertility plays no direct role. It is argued that this is a general result working in stage-structured models with harvest values. In the numerical illustration it is shown that the optimal harvest pattern stays quite stable under various parameter changes. It is revealed which parameters and harvest restrictions that is most important. We also show that the current harvest pattern involves too much yearling harvest compared with the economically efficient level.