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.
2008
Forfattere
Ingrid Holtsmark Gunnhild Wærsted Takle May Bente BrurbergSammendrag
The Gram-positive bacterium Clavibacter michiganensis subsp. sepedonicus is the causal agent of bacterial wilt and ring rot of potato. So far, only two proteins have been shown to be essential for virulence, namely a plasmid-encoded cellulase CelA and a hypersensitive response-inducing protein. We have examined the relative expression of CelA and eight putative virulence factors during infection of potato and in liquid culture, using quantitative real-time PCR. The examined putative virulence genes were celB, a cellulase-encoding gene and genes encoding a pectate lyase, a xylanase and five homologues of the Clavibacter michiganensis subsp. michiganensis pathogenicity factor Pat-1 thought to encode a serine protease. Six of the nine assayed genes were up-regulated during infection of potato, including celA, celB, the xylanase gene, and two of the pat genes. The pectate lyase gene showed only slightly elevated expression, whereas three of the five examined pat genes were down-regulated during infection in potato. Interestingly, the two up-regulated pat genes showed a noticeable sequence difference compared to the three down-regulated pat genes. These results reveal several new proteins that are likely to be involved in Clavibacter michiganensis subsp. sepedonicus pathogenicity.
2007
Forfattere
Liv Guri VelleSammendrag
Informasjonsfaldar om utegangarsau. Faldaren tek føre seg delar av undersøkingane Bioforsk Vest Fureneset har gjort på utegangarsau på Lyngheisenteret på Lygra.
Forfattere
Leif SundheimSammendrag
Norge var eit av dei første land med operativ tørråtevarsling " historisk tilbakeblikk på utviklinga fra 1957 - 2007, med fokus på grunnarbeidet Erling Førsund la ned i starten. Det er ei overordna målsetting i arbeidet for norsk plantehelse å redusere risikoen ved bruk av kjemiske plantevernmiddel. Dyrking av kvalitetspotet krev sprøyting i periodar med fare for spreiing av tørråte, den farlegaste sjukdommen i potet. Presise varslar om når dyrkarane treng å sprøyte og når sprøyting ikkje er naudsynt er eit viktig bidrag til å nå målet.
Forfattere
Leif SundheimSammendrag
Med dagens fytosanitære regelverk og praksis for bekjemping av pærebrann i Noreg er det låg sannsynlegheit for introduksjon av pærebrann til fruktdistrikt og planteskular. Lemping på noverande regelverk og praksis vil føre til moderat risiko for introduksjon
2006
Forfattere
Liv Guri VelleSammendrag
Kronikk i Nationen om gjengroing av kystlyngheiane. Kronikken oppfordrar til fokus på skjøtsel og bruk, politisk vilje, ressursar og heilskapleg tenking, dersom ein skal klare å ta vare på verdiane i dei opne lyngheiane.
Forfattere
Liv Guri VelleSammendrag
Artikkel om kystlyngheiane og gjengroing. Artikkelen tek opp at over 80 % av det opphavlege kystlyngheiarealet har forsvunne, og at ein del av kulturarven vår gror att.
Forfattere
Tor Håkon Sivertsen Janis GailisSammendrag
A web-base system for administrating data from a network of agro meteorological stations is presented, especially the module containing the documentation of the instruments. The quality concept of meteorological data is presented. The system development practice is recently changing from a traditional in-house and vendor controlled system to the global software development in a highly distributed and heterogeneous environments. This can be highly challenging for system development practices related to specific domain activities like collection, control and correction of meteorological and biological data, since the number of involved actor-networks can become large and the interactions between actor-networks then tends to be complex. To utilize the meteorological and biological data in scientific models that has practical implications for the users, and to make the data accessible and representative in different contexts, a large set of actor-networks has to be considered. To illustrate the variety of interactions between actor-networks in the process of the development of a web-based system, the actor-network theory , ANT, (Law, 1992; Latour, 2005; Latour and Woolgar, 1986) is shortly introduced. The actor-network dealing with collection, administration, control, correction and presentation of values of both measured ( by sensors) and derived parameters, is described in a detailed manner. Also the role of the formal and informal specifications is discussed ( Frias et al., 2005) for the actor-networks involved in the process of development. A heterogeneous engineering approach is suggested for the further development of the web-based system, especially the control and correction of the meteorological and biological data. Some features of another system for documentation of instruments, called `Sensor Model Language" is didcussed and commented. We ask, if using ANT to describe the social patterns uncovered during the system development process, can this increase the usability and dynamical features for various actor-networks involved? References: Latour, B., & Woolgar, S.,(1986), Laboratory Life : The construction of scientific facts; Princeton; Princetn university Press. Fries, A. F., Lopez Pombo, C.G., Baum, G.A., Aguirre, N.M., & Maibaum, T.S.E., (2005), Reasoning about static and dynamic properties in alloy: A purely relational approach, ACM Transactions on software engineering and methology, Vol. 14., No 4, October 2005, p. 478-526 Law, J., (1992), Notes on the theory of the actor-network: Ordering, strategy, and heterogeneity, systemiv practice and action research,Springer Netherlands, ISSN: 1094-429x ( Paper) 1573-9295 ( online), D01: 10.1007/BF01059830, Issue: Volume 5, Number 4, August 1992, p. 379-393 Latour, B., (2005), Reassembling the social: An introduction to Actor-network theory; Oxford; Oxford University Press Sivertsen, T.H., 2005, Implementation of a General Documentation System for web-based administration and use of historical series of meteorological and biological data, Physics and Chemistry of the Earth Special Issue: Agrometeorology 2003, Vol 30/1-3 pp 217-222 Sivertsen, T.H., 2005, Discussing scientific methods and the quality of meteorological data, in `Use and Availability of Meteorological Information from Different Sources as Input in Agrometeorological Models", COST ACTIONS 718 `Meteorological Applications for Agriculture", Edited by G. Maracchi, A. Mestre, L. Toulios and B. Gozzini. Sivertsen, T.H, 2005, ", Reflections on the Theme of Classifying, Documenting and Exchanging Meteorological Data", Atmospheric Science Letters, Vol.6 , Issue 3, p 171-175, John Wiley & Son
Forfattere
Tor Håkon SivertsenSammendrag
Elements of the physical background of the phenomenon of internal gravity waves in the atmosphere are discussed , and the classical two-dimensional description of stationary waves is presented. Then the classical linearized system of equations is presented and discussed. The equation of wave energy of stationary waves of Eliassen & Palm (1961) is presented, as well as their statement of the conservation of the vertical flux of wave energy in a large class of systems. The special situation of a vertical layered atmospheric system with a discontinuity ( in the vertical direction) in the temperature of the air, the density of the air or the main stream) is considered. It is shown that the boundary conditions used by Eliassen & Palm (1961) sometimes violate their statement of conservation of the vertical flux of wave energy. References: Eliassen, A., & Palm, E., (1961), On the transfer of energy in stationary mountain waves, Geofysiske Publikasjoner, Oslo Sivertsen, T., (1976), On the transfer of energy in stationary mountain waves in an atmosphere with didcontinous parameters, Meteorologiske annaler Vol. 7 No. 3, Det Norske Meteorologiske Institutt Sivertsen T.H., 2005, Discussing the scientific method and a documentation systems of meteorological and biological parameters, Physics and Chemistry of the Earth Special Issue: Agrometeorology 2003, Vol 30/1-3 pp 35-43
Forfattere
Tor Håkon SivertsenSammendrag
The concept of classification of meteorological and agro meteorological / biological phenomena is defined as merely giving names to observed phenomena. Examples of certain phenomena are shortly presented, and then a rather unusual statement connected to the concept of classification is presented: Any physical and biological phenomenon contains a totality that includes time, space and consciousness. The concept of parameterization is used in the following manner: We connect measurable / quantitative entities to each phenomenon. The concept of parameter is then discussed as well as the ideas of constructing models containing the macro physics of the air or the micro-physics of the air. A few ideas connected to statistical mechanics are mentioned. And some of the ideas of the `physical laws" used in meteorology are discussed. References: Sivertsen T.H., 2005, Discussing the scientific method and a documentation systems of meteorological and biological parameters, Physics and Chemistry of the Earth Special Issue: Agrometeorology 2003, Vol 30/1-3 pp 35-43 Sivertsen, T.H., 2005, Implementation of a General Documentation System for web-based administration and use of historical series of meteorological and biological data, Physics and Chemistry of the Earth Special Issue: Agrometeorology 2003, Vol 30/1-3 pp 217-222 Sivertsen, T.H., 2005, Discussing scientific methods and the quality of meteorological data, in `Use and Availability of Meteorological Information from Different Sources as Input in Agrometeorological Models", COST ACTIONS 718 `Meteorological Applications for Agriculture", Edited by G. Maracchi, A. Mestre, L. Toulios and B. Gozzini. Sivertsen, T.H, 2005, ", Reflections on the Theme of Classifying, Documenting and Exchanging Meteorological Data", Atmospheric Science Letters, Vol.6 , Issue 3, p 171-175, John Wiley & Son
Forfattere
Tor Håkon SivertsenSammendrag
An interpretation of the scientific principle is presented and shortly discussed, containing the concepts of classification of physical phenomena, parameterization, `physical laws", construction of hypotheses and testing. Then the concept of continuity of the real number system ispresented. The Navier-Stokes equations , the equation of continuity, and the energy equations are interpreted , looking at the concepts of molecular diffusion and convective flow, and the physical content of the `physical laws" of conservation of mass, conservation of momentum and conservation of energy. The construction of the Reynolds equation is discussed by looking at the parameterization in time and space of fluid flow of different temporal and spatial scale. Turbulence is then interpreted as phenomena of fluid dynamics on a smaller scale than the scale of the system for making measurements in each operational situation. The discussion is completed by looking once more at the content of the `physical laws" of of conservation of mass, conservation of momentum and conservation of energy. References: Tennekes, H., & Lumley, J.J., (1972). A first course of turbulence. The MIT Press, Cambridge, Massachusets, and London, England. Yaglom, A.M., & Monin, A.S., (1987), statistical Fluid Mechanics, The MIT Press, , Cambridge, Massachusets, and London, England. Siveertsen, T.H.,(2004) Invitation to Conceptual Discussions Concerning the Scope of the Scientific Method and Classification of Meteorological Phenomena and Meteorological Parameters, P 185-190, Selected Papers of the International Conference `Fluxes and Structures in Fluids", St. Petersburg, Russia, June 23-26, 2003, Moscow, IPM RAS, 2004 Sivertsen, T.H.,(2004), Discussing the Concept of Continuity of Continuum Mechanics, P 190-193, Selected Papers of the International Conference `Fluxes and Structures in Fluids", St. Petersburg, Russia, June 23-26, 2003, Moscow, IPM RAS, 2004 Sivertsen, T.H., (2004), Discussing the Concept of Turbulence and a Proposal of a Classification System of Fluid Dynamical Parameters, P 193-196, Selected Papers of the International Conference `Fluxes and Structures in Fluids", St. Petersburg, Russia, June 23-26, 2003, Moscow, IPM RAS, 2004 Sivertsen T.H., 2005, Discussing the scientific method and a documentation systems of meteorological and biological parameters, Physics and Chemistry of the Earth Special Issue: Agrometeorology 2003, Vol 30/1-3 pp 35-43 Sivertsen, T.H, 2005, ", Reflections on the Theme of Classifying, Documenting and Exchanging Meteorological Data", Atmospheric Science Letters, Vol.6 , Issue 3, p 171-175, John Wiley & Sons