K Dewitte

Ghent University, Gent, VLG, Belgium

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Publications (10)73.82 Total impact

  • K Dewitte, J Latré, G Haesaert
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    ABSTRACT: Weed control in sweet lupins is still a problem. Especially the phytotoxicity of herbicides in sweet lupins is not enough studied. Therefore a screening with 16 selected herbicides and 4 lupin varieties has been set up. During the growing season 2005, 10 of the tested herbicides were applied in pre-emergence, 6 in post-emergence. Pre-emergence: Most of the active matters tested in pre-emergence were not phytotoxic for lupins. Pendimethalin (1000 g/ha), linuron (500 g/ha), chlorotoluron (1500 g/ha), prosulfocarb (2400 g/ha), clomazone (72 g/ha), isoxaben (100 g/ha), metamitron (1050 g/ha) and dimethenamid-P (720 g/ha) were applied without causing any significant phytotoxic symptoms. Only the lupins treated with aclonifen (1200 g/ha) showed a significant growth inhibition, 3 weeks after treatment. Significantly more chlorosis was noticed when the lupins were treated with aclonifen or with diflufenican, in preemergence. Post-emergence: In post-emergence, diflufenican (50 g/ha) did not cause any crop damage. Florasulam (5 g/ha) caused almost 100% necrosis in L. albus as well as in L. luteus. Bentazon (652 g/ha), thifensulfuron-methyl (15 g/ha) and metribuzin (175 g/ha) caused obvious necrosis and growth inhibition of the crop. The growth inhibition was significantly more severe for lupins treated with bentazon than if they were treated with thifensulfuron-methyl or metribuzin. Three weeks after treatment, clomazone (90 g/ha) and diflufenican (50 g/ha), did not cause any crop injury at all. The results indicated an interesting range of active matters which can be applied in pre-emergence, but weed control in post-emergence stays difficult.
    Communications in agricultural and applied biological sciences 02/2006; 71(3 Pt A):743-51.
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    ABSTRACT: Based on data in the literature, it remains unclear whether the ionized fraction of serum total magnesium (Mg) is lower in chronic hemodialysis (HD) patients compared to healthy subjects. The ionized fraction of serum total Mg was investigated in 49 HD patients, pre- and post-dialysis, and compared to 30 healthy controls. The quality of the analytical performance of the Mg measurements has been emphasized by applying a reference method and/or rigorous internal quality control (IQC). In addition, the ionized fraction of serum total calcium (Ca) was measured in both populations, because the results for Mg should be related to those of Ca. In HD patients, the ionized fraction of serum total Mg was on average 65% (pre-dialysis 64.2% and post-dialysis 66.2%). In healthy controls, the ionized fraction was 64.9%. When the analytical variability was taken into account, no significant differences (p > 0.05) were observed between pre- and post-dialysis samples and controls. For Ca, an ionized fraction of 55.3% was found in HD patients, which was not significantly different from the fraction obtained in the control group (55.7%). The present study demonstrates that, compared to healthy controls, the ionized fraction of serum total Mg is not different in hemodialysis patients.
    Clinical nephrology 10/2002; 58(3):205-10. · 1.29 Impact Factor
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    Diabetes Care 12/2000; 23(11):1711-2. · 7.74 Impact Factor
  • K Dewitte, D Stöckl, L M Thienpont
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    ABSTRACT: Measurement by ion selective electrode showed that the pH dependency of serum ionised calcium is better described by an inversely S-shaped third-degree function than by the conventionally used logarithmic function.
    The Lancet 12/1999; 354(9192):1793-4. · 39.21 Impact Factor
  • K Dewitte, D Stöckl, L M Thienpont
    Clinica Chimica Acta 05/1999; 282(1-2):227-8. · 2.85 Impact Factor
  • K Dewitte, D Stöckl, L M Thienpont
    Clinical Chemistry 05/1999; 45(4):588-9. · 7.15 Impact Factor
  • L M Thienpont, K Dewitte, D Stöckl
    Clinical Chemistry 02/1999; 45(1):154-5. · 7.15 Impact Factor
  • K Dewitte, D Stöckl, L M Thienpont
    Scandinavian Journal of Clinical and Laboratory Investigation 12/1998; 58(7):603-4. · 1.29 Impact Factor
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    D Stöckl, K Dewitte, L M Thienpont
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    ABSTRACT: We compared the application of ordinary linear regression, Deming regression, standardized principal component analysis, and Passing-Bablok regression to real-life method comparison studies to investigate whether the statistical model of regression or the analytical input data have more influence on the validity of the regression estimates. We took measurements of serum potassium as an example for comparisons that cover a narrow data range and measurements of serum estradiol-17beta as an example for comparisons that cover a wide data range. We demonstrate that, in practice, it is not the statistical model but the quality of the analytical input data that is crucial for interpretation of method comparison studies. We show the usefulness of ordinary linear regression, in particular, because it gives a better estimate of the standard deviation of the residuals than the other procedures. The latter is important for distinguishing whether the observed spread across the regression line is caused by the analytical imprecision alone or whether sample-related effects also contribute. We further demonstrate the usefulness of linear correlation analysis as a first screening test for the validity of linear regression data. When ordinary linear regression (in combination with correlation analysis) gives poor estimates, we recommend investigating the analytical reason for the poor performance instead of assuming that other linear regression procedures add substantial value to the interpretation of the study. This investigation should address whether (a) the x and y data are linearly related; (b) the total analytical imprecision (s(a,tot)) is responsible for the poor correlation; (c) sample-related effects are present (standard deviation of the residuals > s(a,tot)); (d) the samples are adequately distributed over the investigated range; and (e) the number of samples used for the comparison is adequate.
    Clinical Chemistry 11/1998; 44(11):2340-6. · 7.15 Impact Factor
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    ABSTRACT: Industrial adjuvants were tested in combination with benthiavalicarb plus mancozeb (Valbon 1.6 kg/ ha) in the field to investigate their efficacy on foliar late blight caused by 3K\WRSKWKRUDLQIHVWDQV. The tested adjuvant-fungicide treatments for late blight control were applied 6 times at 7-day intervals. The effect of the adjuvant-fungicide treatments on epidemic development, tuber blight and tuber yields were determined. Because of the favourable weather conditions a high disease pressure could be observed. The incidence of foliage blight was scored and at the end of the growing season the disease level was lower in plots sprayed with the Valbon-adjuvant combinations than in plots treated with only Valbon. The addition of an adjuvant had a clearly positive effect on the tuber yield although the differences were not significant. In the plots treated with Valbon 6.9 % infected tubers were observed. The mean tuber infection of plots sprayed with the Valbon-adjuvant combinations fluctuated between 2.3 and 15.6 %.