Staff Publications

Staff Publications

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    'Staff publications' is the digital repository of Wageningen University & Research

    'Staff publications' contains references to publications authored by Wageningen University staff from 1976 onward.

    Publications authored by the staff of the Research Institutes are available from 1995 onwards.

    Full text documents are added when available. The database is updated daily and currently holds about 240,000 items, of which 72,000 in open access.

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    We will mail you new results for this query: keywords==stabiele isotopen
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How much bio is in there? Can stable isotopes be used to determine the bio-based content of products?
Broek, L.A.M. van den; Veer, G. van der; Zee, M. van der - \ 2015
Bioplastics Magazine 10 (2015)5. - ISSN 1862-5258 - p. 18 - 22.
isotopen - stabiele isotopen - biobased economy - materialen uit biologische grondstoffen - samenstelling - analytische methoden - isotopes - stable isotopes - biobased materials - composition - analytical methods
Can stable isotopes be used to determine the bio-based content of products?
Passage of feed in dairy cows : use of stable isotopes to estimate passage kinetics through the digestive tract of dairy cows
Warner, D. - \ 2013
Wageningen University. Promotor(en): Wouter Hendriks, co-promotor(en): Wilbert Pellikaan; Jan Dijkstra. - S.l. : s.n. - ISBN 9789461736833 - 163
melkkoeien - melkvee - voer - voedingsstoffen - spijsvertering - spijsverteringskanaal - kinetica - stabiele isotopen - verteerbaarheidsmerkers - rundveevoeding - diervoeding - voedingsfysiologie - dairy cows - dairy cattle - feeds - nutrients - digestion - digestive tract - kinetics - stable isotopes - digestibility markers - cattle feeding - animal nutrition - nutrition physiology

Dairy cows possess a unique digestive system to digest fibre-rich diets. Ingested feed is retained and degraded in the rumen by the enteric microbial population and is passed from the rumen to the following segments of the digestive tract. Passage of feed determines energy and protein supply to the animal and is a key parameter in several feed evaluation models for ruminants. Yet, quantitative data on passage of feed and particularly of single feed components are limited. Common techniques used to determine fractional passage rates of feed typically include indigestible markers that are not able to describe passage of distinct feed components. This thesis describes the use of stable isotope labelled feed components as a novel marker to determine feed type and feed component specific fractional passage rates. In a series of in vivoexperiments, fractional passage rates of a typical dairy ration, including grass silage, maize silage and concentrates, were determined. The use of carbon (13C) and nitrogen (15N) stable isotopes as an internal marker inherent to the diet allowed to specifically determine fractional passage rates of plant cell walls such as structural fibre, fibre-bound nitrogen, n-alkanes, and intracellular components such as starch and total nitrogen. For grass silage and maize silage, stable isotopes gave slower fractional rumen passage rates compared to the commonly used external marker chromium mordanted fibre; for concentrates, stable isotopes gave faster rates than the external marker. Among isotopic labelled fractions, 13C-labelled fibre and 15N-labelled fibre-bound nitrogen gave the slowest rates. The isotopic signature of single feed components and further application of stable isotopes on a wider range of feeds and feed components offers scope for the future for a more detailed insight into nutrient-specific passage kinetics. This will ultimately allow to quantify nutrient supply in response to changes in diet composition and quality, and model animal response in relation to optimal animal performance, environmental and animal-health issues.

Reproductive biology and induced sterility as determinants for genetic control of mosquitoes with the Sterile Insect Technique
Helinski, M. - \ 2008
Wageningen University. Promotor(en): Marcel Dicke, co-promotor(en): B.G.J. Knols. - S.l. : S.n. - ISBN 9789085049555 - 203
steriele insecten techniek - genetische gewasbescherming - sterilisatie - ioniserende straling - stabiele isotopen - ziekten overgebracht door muskieten - malaria - anopheles arabiensis - paarconcurrentie - sudan - sterile insect release - genetic control - sterilization - ionizing radiation - stable isotopes - mosquito-borne diseases - mating competitiveness
Malaria remains an important health issue in sub-Saharan Africa, and new methods to reduce the disease are needed. In this thesis, the use of the Sterile Insect Technique (SIT) against the African malaria vector Anopheles arabiensis was explored. The SIT relies on the releases of large numbers of sterilised males. If the sterile males are successful in competing for mates and the females use their sperm for fertilisation, the wild population is reduced. Ultimately, this can lead to a reduction in disease incidence. Sterilisation of the sperm cells occurs by ionising radiation, resulting in the death of the developing embryo after fertilisation. Somatic cells are also damaged, which can lead to a reduced mating competitiveness of the males.
In this thesis I investigated 1) the relationship between dose and induced sterility for pupal or adult stage irradiation, 2) sperm quantity and sperm length polymorphism and the influence of irradiation, 3) the use of stable isotopes to determine mating in mosquitoes, 4) the incidence of multiple mating in relation to irradiation, 5) the fitness of irradiated males in terms of survival and mating competitiveness, and 6) the use of a field cage for mating studies, and the small-scale feasibility of the SIT in Sudan.
Results showed that even though the dose-response curves between dose and induced sterility were largely similar for pupae and adults, irradiation of adults resulted in a better competitiveness compared to pupal irradiation. A negative relationship between dose and competitiveness was observed for pupal stage irradiation. In addition, radiation during the pupal stage affected the number of spermatozoa in the testes and the distribution of sperm lengths, but no impact on the incidence of multiple mating could be observed. Stable isotopes were used successfully to determine paternity in mating. Mating competitiveness of males irradiated as pupae could be improved by a three-fold increase in their number compared to un-irradiated males, but only for the partially-sterilising dose. The small-scale irradiation and transportation of insects in Sudan was feasible, and the preparation of the field cage for experiments successful.
It is concluded that from a biological viewpoint the irradiation of adults would be recommended; however, the feasibility of adult irradiation on a large scale is questionable. The next steps would be to scale up irradiation procedures to accommodate much larger numbers of insects, and to determine male competitiveness in the semi-field system in Sudan. However, many other factors including mass rearing, sexing, and release methodology, are of importance for an SIT programme and only when all components are in place can the true feasibility of the SIT in Sudan be determined.

Uit de mest- en mineralenprogramma's : Gebruik van stabiele isotopen in mest- en mineralenonderzoek
Groenigen, J.W. van - \ 2005
Wageningen : Alterra (Informatieblad mest- en mineralenprogramma's 398.63) - 2
nitraat - mineralen - denitrificatie - stabiele isotopen - analytische methoden - isotopenlabelling - meting - bereikt resultaat - nitrate - minerals - denitrification - stable isotopes - analytical methods - isotope labeling - measurement - achievement
De commissie Spiertz II heeft in 2000 aanbevolen om geavanceerde en veelbelovende onderzoeksmethodieken toe te passen in het mest- en mineralenonderzoek. Dit heeft geleid tot een aantal proeven waarin het gebruik van stabiele isotopen is verkend. Deze proeven lopen in 2005 ten einde en in dit informatieblad wordt een voorlopige balans opgemaakt van het gebruik van stabiele isotopen in het mest- en mineralen onderzoek
Nitraatconcentraties in het bovenste grondwater in een bufferstrook en aangrenzende akker; resultaten van twee jaar experimenteel ondezoek aan een grasbufferstrook op zandgrond op akkerbouwbedrijf Vredepeel
Beek, C.L. ; Heinen, M. ; Clevering, O.A. ; Kleef, J. van - \ 2005
Wageningen : Alterra (Alterra-rapport 1263) - 78
nitraat - fosfaat - bodemwater - denitrificatie - uitspoelen - stabiele isotopen - akkerbouw - nederland - bodemchemie - bufferzones - de peel - nitrate - phosphate - soil water - soil chemistry - denitrification - leaching - stable isotopes - arable farming - netherlands - buffer zones
Gedurende twee uitspoelseizoenen zijn hydrologische en chemische bepalingen uitgevoerd in een grasbufferstrook en in de aangrenzende akker op een akkerbouwbedrijf op zandgrond. Nitraatconcentraties in het (bovenste) grondwater waren lager onder de bufferstrook dan onder de akker. Stabiele isotopen-ratio’s, ondersteund door Cl/NO3-N verhoudingen, gaven aan dat deze daling in een aantal gevallen veroorzaakt werd door denitrificatie in de bodem. De nitraatconcentraties in de bufferstrook waren gemiddeld 40% tot 55% lager dan in de akker. Echter, omdat het hier een observationele proef betreft konden geen causale verbanden worden gelegd
Stable nitrogen isotopes : study about its use in the assessment of denitrification and N fixation
Carratala Sanchez, C. - \ 2001
Wageningen : Plant Research International (Note / Plant Research International 145) - 19
stikstof - stikstofkringloop - stabiele isotopen - stikstoffixatie - denitrificatie - meting - methodologie - nitrogen - nitrogen cycle - stable isotopes - nitrogen fixation - denitrification - measurement - methodology
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