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.
2002
Forfattere
Nicholas ClarkeSammendrag
In natural waters, total organic carbon (TOC) is the sum of particulate and dissolved organic carbon. Dissolved organic carbon (DOC) is operationally defined, usually as organic carbon that passes through a 0.45 µm filter. Cellulose acetate or nitrate filters should not be used for this purpose due to contamination or adsorption problems. Glass fibre filters are preferable. Although the discussion below concerns DOC, much of it applies to TOC as well. Organic carbon is most often determined after oxidation to CO2 using combustion, an oxidant such as persulphate, UV or other high-energy radiation, or a combination of some of these. If only UV radiation with oxygen as oxidant is used, low DOC values may be obtained in the presence of humic substances. A variety of methods are used for detection, including infrared spectrometry, titration and flame ionization detection after reduction to methane. Always follow the instrument manufacturer’s instructions. For determination of dissolved organic carbon, dissolved inorganic carbon must be either removed by purging the acidified (for example with phosphoric acid) sample with a gas which is free from CO2 and organic compounds, or determined and subtracted from the total dissolved carbon. If acidification followed by purging is used, care should be taken as volatile organic compounds may also be lost. After acidification, remove CO2 by blowing a stream of pure carbon-free inert gas through the system for at least 5 minutes. Carbon is ubiquitous in nature, so reagents, water, and glassware cannot be completely cleaned of it. Method interferences (positive bias) may be caused by contaminants in the carrier gas, dilution water, reagents, glassware, or other sample processing hardware (for example a homogenization device). All of these materials must be routinely demonstrated to be free from interference under the conditions of analysis by running reagent blanks. Plastic bottles can bleed carbon into water samples, especially when they are new, or when they are used for low-level samples (less than 200 ppb C). Any new bottles (especially plastic) should ideally be filled with clean water for a period of several days or boiled in water for a few hours before use. The use of high purity or purified reagents and gases helps to minimise interference problems. It is very important to use ultra-pure water with a carbon filter or boiled distilled water just before preparing stock and standard solutions, in order to remove dissolved CO2. The stock solution should not be kept too long (about one week). For most DOC instruments a correction for DOC (due to dissolved CO2) in the dilution water used for calibration standards is necessary, especially for standards below 10 ppm C. The carbon in the blank should only be subtracted from standards and not from samples. For calibration, standard solutions are most often potassium hydrogen phthalate for total dissolved carbon and sodium bicarbonate for dissolved inorganic carbon. The DOC concentration should be within the working range of the calibration. If necessary the sample can be diluted. Sample DOC below about 50 ppb C can be affected by atmospheric exposure. In these cases, sampling bottles should be kept closed when possible, and autosampler vials should be equipped with septa for needle piercing by the autosampler.
Forfattere
Sverre KobroSammendrag
Diagnostic characters of the second-stage larvae of Oxythrips bicolor and Oxythrips ajugae are shown. The larva of the former has not been described prviously.
Forfattere
Tor MykingSammendrag
Det er ikke registrert sammendrag
Forfattere
Tor MykingSammendrag
Det er ikke registrert sammendrag
Forfattere
Stig Strandli GezeliusSammendrag
Det er ikke registrert sammendrag
Forfattere
Klaus MittenzweiSammendrag
Det er ikke registrert sammendrag
Sammendrag
Det er ikke registrert sammendrag
Forfattere
Sverre KobroSammendrag
Gusathion og de andre fosformidlene er nå definitivt på vei ut av frukthagene. Det er flere ting vi kan gjøre for å møte problemene som oppstår, og forberedelsene kan begynne straks. Jeg tillater meg å komme med noen "luftige" forslag.
Forfattere
Mekjell MelandSammendrag
Eplesorten "Discovery" poda på 8 grunnstammervart prøvde i intensive plantesystem i fem år ved to lokalitetar. Grunnstammene var to seleksjonar av M.9 (EMLA, RN.29), to frå den Polske (P) serien (P.59, P.60), tre frå Geneva (G) serien (G.30, G.78730-026, G.202) and M.26. Tre-storleiken var signifikant påverka av grunnstammene. P.59, G.78730-026 og M.9 RN.29 gav dei minste og G.30 og G.202 dei største trea målt som stammetverrmål. Avlinga var størst på P.59 og G.30 fylgd av G.202, P.60 and M.9 EMLA. Effektiviteten var største hjå tre av P.59 og dei to M.9 klonane. Det var liten skilnad på fruktvektene. Fruktkvaliten var generelt høg og det var liten skilnad mellom dei ulike grunnstammene.
Forfattere
Per Jarle MøllerhagenSammendrag
Dyrkingsteknikk for potetsorter i Norge. Nitrogengjødsling, setteavstander, settepotetstørrelse, forbehandling av settepotetene samt styrker og svakheter vedr sortene