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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Hygienic behaviour in honeybees: a comparison of two recording methods and estimation of genetic parameters
Facchini, Elena ; Bijma, Piter ; Pagnacco, Giulio ; Rizzi, Rita ; Brascamp, Evert Willem - \ 2019
Apidologie 50 (2019)2. - ISSN 0044-8435 - p. 163 - 172.
freeze-killed brood test - heritability - honeybee - hygienic behaviour - repeatability

Hygienic behaviour (HB) in honeybees reflects social immunity against diseases and parasites. Young bees showing HB detect, uncap, and remove infested brood from a colony. We developed a new variant of freeze-killed brood (FKB*) test to optimise the duration of the HB test, the costs, and safety for the operator. In 2016, we performed a comparison between traditional FKB and FKB* on 25 unselected and unrelated colonies in the apiary of the University of Milano. To estimate repeatability and heritability, in 2017 and 2018, FKB* was used to phenotype, respectively, 56 and 95 colonies twice, in the context of a breeding programme. FKB* took less time and required a smaller amount of liquid nitrogen. The two methods showed a correlation between colony effects of 0.93, indicating that they measure the same trait. For single records, the phenotypic correlation between both methods was 0.64. Estimated heritability and repeatability for single records HB were 0.23 and 0.24, respectively, whilst heritability for the average HB value of two records was 0.37.

Comment on “Most computational hydrology is not reproducible, so is it really science?” by Christopher Hutton et al.
Melsen, Lieke A. ; Torfs, Paul J.J.F. ; Uijlenhoet, Remko ; Teuling, Ryan - \ 2017
Water Resources Research 53 (2017)3. - ISSN 0043-1397 - p. 2568 - 2569.
computational hydrology - repeatability - reproducibility

We discuss two definitions of reproducibility, and question if both definitions are required to be met in computational hydrological studies.

Physical activity and risk of breast cancer overall and by hormone receptor status: The European prospective investigation into cancer and nutrition
Steindorf, K. ; Ritte, R. ; Eomois, P.P. ; Lukanova, A. ; Tjonneland, A. ; Johnsen, N.F. ; Overvad, K. ; Ostergaard, J.N. ; Clavel-Chapelon, F. ; Duijnhoven, F.J.B. van - \ 2013
International Journal of Cancer 132 (2013)7. - ISSN 0020-7136 - p. 1667 - 1678.
postmenopausal women - estrogen-receptor - activity questionnaire - body-size - repeatability - validity - health - prevention - exercise - age
Physical activity is associated with reduced risks of invasive breast cancer. However, whether this holds true for breast cancer subtypes defined by the estrogen receptor (ER) and the progesterone receptor (PR) status is controversial. The study included 257,805 women from the multinational EPIC-cohort study with detailed information on occupational, recreational and household physical activity and important cofactors assessed at baseline. During 11.6 years of median follow-up, 8,034 incident invasive breast cancer cases were identified. Data on ER, PR and combined ER/PR expression were available for 6,007 (67.6%), 4,814 (54.2%) and 4,798 (53.9%) cases, respectively. Adjusted hazard ratios (HR) were estimated by proportional hazards models. Breast cancer risk was inversely associated with moderate and high levels of total physical activity (HR = 0.92, 95% confidence interval (CI): 0.86–0.99, HR = 0.87, 95%-CI: 0.79–0.97, respectively; p-trend = 0.002), compared to the lowest quartile. Among women diagnosed with breast cancer after age 50, the largest risk reduction was found with highest activity (HR = 0.86, 95%-CI: 0.77–0.97), whereas for cancers diagnosed before age 50 strongest associations were found for moderate total physical activity (HR = 0.78, 95%-CI: 0.64–0.94). Analyses by hormone receptor status suggested differential associations for total physical activity (p-heterogeneity = 0.04), with a somewhat stronger inverse relationship for ER+/PR+ breast tumors, primarily driven by PR+ tumors (p-heterogeneity <0.01). Household physical activity was inversely associated with ER–/PR– tumors. The results of this largest prospective study on the protective effects of physical activity indicate that moderate and high physical activity are associated with modest decreased breast cancer risk. Heterogeneities by receptor status indicate hormone-related mechanisms.
Prospective study on physical activity and risk of in situ breast cancer
Steindorf, K. ; Ritte, R. ; Tjonneland, A. ; Johnsen, N.F. ; Overvad, K. ; Ostergaard, J.N. ; Boeing, H. ; Trichopoulou, A. ; Bueno de Mesquita, H.B. ; Duijnhoven, F.J.B. van; Monninkhof, E.M. ; Khaw, K.T. ; Wareham, N.J. ; Wark, P.A. ; Riboli, E. ; Kaaks, R. - \ 2012
Cancer Epidemiology Biomarkers and Prevention 21 (2012)12. - ISSN 1055-9965 - p. 2209 - 2219.
postmenopausal women - activity questionnaire - biologic mechanisms - ductal carcinoma - nutrition - validity - repeatability - exercise - cohort
Background: Physical activity has been identified as protective factor for invasive breast cancer risk, whereas comparable studies on in situ carcinoma are rare. Methods: The study included data from 283,827 women of the multinational European Prospective Investigation into C7ancer and Nutrition (EPIC)-cohort study. Detailed information on different types of physical activity conducted during the prior year, such as occupational, recreational, and household activity, as well as on important cofactors, was assessed at baseline. Adjusted HRs for in situ breast cancer were estimated by Cox proportional hazards models. Results: During a median follow-up period of 11.7 years, 1,059 incidents of breast carcinoma in situ were identified, in crude and adjusted multivariable models, no associations were found for occupational, household, and recreational physical activity. Furthermore, total physical activity was not associated with risk of in situ breast cancer. Comparing moderately inactive, moderately active, and active participants with inactive study participants resulted in adjusted HRs of 0.99 [95% confidence interval (CI), 0.83-1.19], 0.99 (95% CI, 0.82-1.20), and 1.07(95% CI, 0.81-1.40), respectively (P value of trend test: 0.788). No inverse associations were found in any substrata defined by age at diagnosis or body mass index (BMI) status. Conclusions: In this large prospective study, we did not find any evidence of an association between physical activity and in situ breast cancer risk. It not by chance, the contrast between our results for carcinoma in situ and the recognized inverse association for invasive breast cancer suggests that physical activity may have stronger effects on proliferation and late stage carcinogenesis. Cancer Epidemiol Biomarkers Prev; 21(12); 2209-19. (C)2012 AACR.
Validity of a short questionnaire to assess physical activity in 10 European countries
Feskens, E.J.M. - \ 2012
European Journal of Epidemiology 27 (2012)1. - ISSN 0393-2990 - p. 15 - 25.
activity energy-expenditure - combined heart-rate - cancer - accelerometry - repeatability - adults - reliability - actiheart - accuracy - sensor
To accurately examine associations of physical activity (PA) with disease outcomes, a valid method of assessing free-living activity is required. We examined the validity of a brief PA questionnaire (PAQ) used in the European Prospective Investigation into Cancer and Nutrition (EPIC). PA energy expenditure (PAEE) and time spent in moderate and vigorous physical activity (MVPA) was measured in 1,941 healthy individuals from 10 European countries using individually-calibrated combined heart-rate and movement sensing. Participants also completed the short EPIC-PAQ, which refers to past year’s activity. Pearson (r) and Spearman (s) correlation coefficients were calculated for each country, and random effects meta-analysis was used to calculate the combined correlation across countries to estimate the validity of two previously- and one newly-derived ordered, categorical PA indices (“Cambridge index”, “total PA index”, and “recreational index”) that categorized individuals as inactive, moderately inactive, moderately active, or active. The strongest associations with PAEE and MVPA were observed for the Cambridge index (r = 0.33 and r = 0.25, respectively). No significant heterogeneity by country was observed for this index (I2 = 36.3%, P = 0.12; I2 = 0.0%, P = 0.85), whereas heterogeneity was suggested for other indices (I2 > 48%, P <0.05, I2 > 47%, P <0.05). PAEE increased linearly across self-reported PA categories (P for trend
Mechanisms regulating follicle wave patterns in the bovine estrous cycle investigated with a mathematical model
Boer, H.M.T. ; Röblitz, S. ; Stötzel, C. ; Veerkamp, R.F. ; Kemp, B. ; Woelders, H. - \ 2011
Journal of Dairy Science 94 (2011)12. - ISSN 0022-0302 - p. 5987 - 6000.
stimulating-hormone - dairy-cows - dynamics - heifers - association - cattle - prostaglandin-f2-alpha - repeatability - manipulation - fertility
A normal bovine estrous cycle contains 2 or 3 waves of follicle development, and ovulation takes place in the last wave. However, the biological mechanisms that determine whether a cycle has 2 or 3 waves have not been elucidated. In a previous paper, we described a mathematical model of the bovine estrous cycle that generates cyclical fluctuations of hormones, follicles, and corpora lutea in estrous cycles of approximately 21 d for cows with a normal estrous cycle. The parameters in the model represent kinetic properties of the system with regard to synthesis, release, and clearance of hormones and growth and regression of follicles and corpora lutea. The initial model parameterization resulted in estrous cycles with 3 waves of follicular growth. Here, we use this model to explore which physiological mechanisms could affect the number of follicular waves. We hypothesized that some of the parameters related to follicle growth rate or to the time point of corpus luteum regression are likely candidates to affect the number of waves per cycle. We performed simulations with the model in which we varied the values of these parameters. We showed that variation of (combinations of) model parameters regulating follicle growth rate or time point of corpus luteum regression can change the model output from 3 to 2 waves of follicular growth in a cycle. In addition, alternating 2- and 3-wave cycles occurred. Some of the parameter changes seem to represent plausible biological mechanisms that could explain these follicular wave patterns. In conclusion, our simulations indicated likely parameters involved in the mechanisms that regulate the follicular wave pattern, and could thereby help to find causes of declined fertility in dairy cows.
Re-mating in otter (Luntra luntra)
Broekhuizen, S. ; Lammertsma, D.R. ; Müskens, G.J.D.M. - \ 2007
Lutra 50 (2007)2. - ISSN 0024-7634 - p. 135 - 139.
lutra lutra - bevruchting - bevruchtingsvermogen - vrouwelijke vruchtbaarheid - herhaalbaarheid - fertilization - fertilizing ability - female fertility - repeatability
De mogelijkheid van dubbele bevruchting bij de otter wordt nader beschouwd nadat bij een in mei 2005 doodgereden otter ook 3 blastocysten naast 3 morula's in de baarmoeder werden aangetroffen. Dit gelijktijdig voorkomen van verschillende ontwikkelingsstadia van bevruchte eicellen duidt namelijk op herhaalde bevruchting in verschillende perioden van de oestrus
Assessing the repeatability and reproducibility of the Leg Score: a Dutch Claw Health Scoring System for dairy cattle
Holzhauer, M. ; Middelesch, H. ; Bartels, C.J. ; Frankena, K. ; Verhoeff, J. ; Noordhuizen-Stassen, E.N. ; Noordhuizen, J.P.T.M. - \ 2005
Tijdschrift voor Diergeneeskunde 130 (2005)14-15. - ISSN 0040-7453 - p. 440 - 443.
melkveehouderij - klauwen - hoeven - afknippen - herhaalbaarheid - timing - dierverzorging - observatie - dairy farming - claws - hooves - clipping - repeatability - timing - care of animals - observation - reproductive-performance - floor systems - lameness - cows - associations - disorders - disease - lesions - traits - herds
The optimal moment for trimming the claws of all dairy cows in a herd was investigated by assessing the external rotation of the hind claws of individual cows relative to the spinal column. This leg score consisted of three independent descriptors: 1 (good/ normal), 2 (moderately deviant), and 3 (severely deviant). This study assessed the repeatability and the reproducibility of the leg score system, and the consistency of the advice given subsequently about trimming of the hind claws of all cows in the herd. Repeatability was assessed for 52 cows that were scored twice on the same day by 11 observers; the kappa value ranged from 0.17 to 0.66 (mean: 0.36). The probability of the same result for both assessments ranged from 0.49 to 0.80 (mean: 0.61). Claw trimming was advised if at least 20% of the cows had a leg score of 3. On the basis of the scores, 3 observers consistently advised trimming of the hind claws of all the cows in the herd, and 6 observers consistently advised against the need for trimming in the short term; 2 observers had an inconsistent advice. The reproducibility of the scoring system was assessed in two dairy herds (62 and 50 cows). Eight observers evaluated the leg score of the cows of both herds on the same day. The mean kappa value of the leg score for all pairs of different observers (A-B, A-C etcetera) was 0.24 [-0.08-0.49]. In conclusion, the leg score is not a reliable method for determining the optimal moment for claw trimming in dairy cattle. The reasons for the inconsistent observations require further investigation
The optimal moment for trimming the claws of all dairy cows in a herd was investigated by assessing the external rotation of the hind claws of individual cows relative to the spinal column. This leg score consisted of three independent descriptors: 1 (good/normal), 2 (moderately deviant), and 3 (severely deviant). This study assessed the repeatability and the reproducibility of the leg score system, and the consistency of the advice given subsequently about trimming of the hind claws of all cows in the herd. Repeatability was assessed for 52 cows that were scored twice on the same day by 11 observers; the kappa value ranged from 0.17 to 0.66 (mean: 0.36). The probability of the same result for both assessments ranged from 0.49 to 0.80 (mean: 0.61). Claw trimming was advised if at least 20 % of the cows had a leg score of 3. On the basis of the scores, 3 observers consistently advised trimming of the hind claws of all the cows in the herd, and 6 observers consistently advised against the need for trimming in the short term; 2 observers had an inconsistent advice. The reproducibility of the scoring system was assessed in two dairy herds (62 and 50 cows). Eight observers evaluated the leg score of the cows of both herds on the same day. The mean kappa value of the leg score for all pairs of different observers (A-B, A-C etcetera) was 0.24 [-0.08-0.49]. In conclusion, the leg score is not a reliable method for determining the optimal moment for claw trimming in dairy cattle. The reasons for the inconsistent observations require further investigation.
Reproducibility and relative validity of the Short Questionnaire to Assess Health-enhancing physical activity
Wendel-Vos, G.C.W. ; Schuit, A.J. ; Saris, W.H.M. ; Kromhout, D. - \ 2003
Journal of Clinical Epidemiology 56 (2003). - ISSN 0895-4356 - p. 1163 - 1169.
computer-science - accelerometer - repeatability - reliability
Objective: The purpose of this study is to determine reproducibility and relative validity of the Short QUestionnaire to ASsess Health-enhancing physical activity (SQUASH). Methods: Participants (36 men and 14 women, aged 27-58) were asked to complete the SQUASH twice with an inbetween period of approximately 5 weeks. In addition, participants wore the Computer Science and Applications (CSA) Activity Monitor for a 2-week period following the first questionnaire. Results: The Spearman correlation for overall reproducibility of the SQUASH was 0.58 (95%-CI 0.36-0.74). Correlations for the reproducibility of the separate questions varied between 0.44 and 0.96. Spearman's correlation coefficient between CSA readings and the total activity score was 0.45 (95%-CI 0.17-0.66). Conclusion: In conclusion, the SQUASH is a fairly reliable and reasonably valid questionnaire and may be used to order subjects according to their level of physical activity in an adult population. Because the SQUASH is a short and simple questionnaire, it may proof to be a very useful tool for the evaluation of health enhancing physical activity in large populations. (C) 2003 Elsevier Inc. All rights reserved.
De juistheid en herhaalbaarheid van volumina gepipetteerd met een microman positive displacement pipet en een glazen volumepipet
Lasaroms, J.J.P. - \ 1999
Wageningen : Rijkskwaliteitsinstituut voor Land- en Tuinbouwproducten (RIKILT) (Rapport / RIKILT-DLO 99.012) - 6
nauwkeurigheid - herhaalbaarheid - methodologie - analytische methoden - analytische scheikunde - accuracy - repeatability - methodology - analytical methods - analytical chemistry
Betrouwbaarheid en herhaalbaarheid microscopische analysemethode diermeel
Voet, H. van der; Jong, J. de; Pinckaers, V.G.Z. - \ 1999
Wageningen : DLO-Rijks-Kwaliteitsinstituut voor land- en tuinbouwprodukten (RIKILT-DLO) (Rapport / RIKILT-DLO 99.015) - 13
analyse - microscopie - statistische analyse - detectie - voer van dierlijke oorsprong - beendermeel - herhaalbaarheid - nauwkeurigheid - analysis - microscopy - statistical analysis - detection - feed of animal origin - bone meal - repeatability - accuracy
Precision of test methods : determination of repeatability and reproducibility by inter-laboratory tests : application in development and assessment of dairy methodology
Werdmuller, G.A. ; Ruig, W.G. de - \ 1983
Wageningen : RIKILT (Verslag / RIKILT 83.23) - 14
zuiveltechnologie - zuivelchemie - normen - laboratoriummethoden - herhaalbaarheid - voortplantingsvermogen - dairy technology - dairy chemistry - standards - laboratory methods - repeatability - reproductive performance
The International Standard ISO 5725 is sometimes considered to be too extended for practical use in the development and assessment of dairy methodology. Therefore the Joint IDF/ISO/AOAC Group of Experts E 30 Statistics of analytical data - decided upon a simplified description, based on ISO 5725, to he more easily applied by dairy scientists. This report comprises an abstract from ISO 5725 intended as a practical guideline in computing repeatability (r) and reproducibility (R). The computation in this report is identical to that of ISO 5725. Theoretical considerations and further instructions in ISO 5725 are dropped here. However, all items discussed in ISO 5725 are succinctly mentioned in this report, so that those who are interested can consult the original standard.
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