704 research outputs found
Verplichte zeggenschap van aandeelhouders volgens de regels van grote effectenbeurzen in de EU
No full textVerplichte zeggenschap van aandeelhouders volgens de regels van grote effectenbeurzen in de EU
No full textVerplichte zeggenschap van aandeelhouders volgens de regels van grote effectenbeurzen in de EU
No full textDevelopmental stress predicts social network position
No full textN.J.B. was funded by a Netherlands Organisation for Scientific Research Rubicon grant and D.R.F. was funded by grants from NSF (NSF-IOS1250895) to Margaret Crofoot and BBSRC (BB/L006081/1) to Ben Sheldon. K.A.S. was funded by a BBSRC David Phillips Research Fellowship.The quantity and quality of social relationships, as captured by social network analysis, can have major fitness consequences. Various studies have shown that individual differences in social behaviour can be due to variation in exposure to developmental stress. However, whether these developmental differences translate to consistent differences in social network position is not known. We experimentally increased levels of the avian stress hormone corticosterone (CORT) in nestling zebra finches in a fully balanced design. Upon reaching nutritional independence, we released chicks and their families into two free-flying rooms, where we measured daily social networks over five weeks using passive integrated transponder tags. Developmental stress had a significant effect on social behaviour: despite having similar foraging patterns, CORT chicks had weaker associations to their parents than control chicks. Instead, CORT chicks foraged with a greater number of flock mates and were less choosy with whom they foraged, resulting in more central network positions. These findings highlight the importance of taking developmental history into account to understand the drivers of social organization in gregarious species.Peer reviewe
Jackdaw nestlings can discriminate between conspecific calls but do not beg specifically to their parents
No full textThis is a pre-copyedited, author-produced PDF of an article accepted for publication in Behavioral Ecology following peer review. The definitive publisher-authenticated version Lies Zandberg, Jolle W. Jolles, Neeltje J. Boogert, and Alex Thornton
Jackdaw nestlings can discriminate between conspecific calls but do not beg specifically to their parents
Behavioral Ecology (2014) 25 (3): 565-573 first published online February 28, 2014 doi:10.1093/beheco/aru026 is available online at: http://intl-beheco.oxfordjournals.org/content/25/3/565.The ability to recognize other individuals may provide substantial benefits to young birds, allowing them to target their begging efforts appropriately, follow caregivers after fledging, and establish social relationships later in life. Individual recognition using vocal cues is likely to play an important role in the social lives of birds such as corvids that provision their young postfledging and form stable social bonds, but the early development of vocal recognition has received little attention. We used playback experiments on jackdaws, a colonial corvid species, to test whether nestlings begin to recognize their parents’ calls before fledging. Although the food calls made by adults when provisioning nestlings were individually distinctive, nestlings did not beg preferentially to their parents’ calls. Ten-day-old nestlings not only responded equally to the calls of their parents, neighboring jackdaws whose calls they were likely to overhear regularly and unfamiliar jackdaws from distant nest boxes, but also to the calls of rooks, a sympatric corvid species. Responses to rooks declined substantially with age, but 20- and 28-day-old nestlings were still equally likely to produce vocal and postural begging responses to parental and nonparental calls. This is unlikely to be due to an inability to discriminate between calls, as older nestlings did respond more quickly and with greater vocal intensity to familiar calls, with some indication of discrimination between parents and neighbors. These results suggest that jackdaws develop the perceptual and cognitive resources to discriminate between conspecific calls before fledging but may not benefit from selective begging responses
Effects of CO2 on H2O band profiles and band strengths in mixed H2O:CO2 ices
No full textH2O is the most abundant component of astrophysical ices. In most lines of sight it is not possible to fit both the H2O 3 m stretching, the 6 m bending intensities with a single pure H2O spectrum. Recent Spitzer observations have revealed CO2 ice in high abundances and it has been suggested that CO2 mixed into H2O ice can affect the positions, shapes and relative strengths of the 3 m and 6 m bands. We investigate whether the discrepancy in intensity between H2O bands in interstellar clouds and star forming regions can be explained by CO2 mixed into the observed H2O ice affecting the bands differently. Laboratory infrared transmission spectroscopy is used to record spectra of H2O:CO2 ice mixtures at astrophysically relevant temperatures and composition ratios. The H2O peak profiles and band strengths are significantly different in H2O:CO2 ice mixtures compared to pure H2O ice. The ratio between the strengths of the 3 m and 6 m bands drops linearly with CO2 concentration such that it is 50% lower in a 1:1 mixture compared to pure H2O ice. In all H2O:CO2 mixtures, a strong free-OH stretching band appears around 2.73 m, which can be used to put an upper limit on the CO2 concentration in the H2O ice. The H2O bending mode profile also changes drastically with CO2 concentration; the broad pure H2O band gives way to two narrow bands as the CO2 concentration is increased. This makes it crucial to constrain the environment of H2O ice to enable correct assignments of other species contributing to the interstellar 6 m absorption band. The amount of CO2 present in the H2O ice of B5:IRS1 is estimated by simultaneously comparing the H2O stretching and bending regions and the CO2 bending mode to laboratory spectra of H2O, CO2, H2O:CO2 and HCOOH
Euphresco Sendo: An international laboratory comparison study of molecular tests for Synchytrium endobioticum detection and identification
No full textAn international test performance study (TPS) was organised to generate validation data for three molecular Synchytrium endobioticum tests: van den Boogert et al. (European Journal of Plant Pathology 113, 47–57, 2005), and van Gent-Pelzer et al. (European Journal of Plant Pathology, 126, 129-133, 2010) for the detection of S. endobioticum, and the pathotype 1(D1) identification test described by Bonants et al. (European Journal of Plant Pathology, 143, 495-506, 2015). Two TPS rounds were organised focussing on different test matrices, i.e. round 1: warted potato tissue, and round 2: resting spore suspensions. When using the tests for detection and identification of S. endobioticum in warted potato tissue, no significant differences were observed for diagnostic sensitivity, diagnostic specificity, overall accuracy, analytical sensitivity and robustness. When using the tests for detection and identification of S. endobioticum in resting spore suspensions, the van den Boogert and van Gent-Pelzer tests significantly outperform the Bonants test for diagnostic sensitivity and diagnostic specificity. For overall accuracy and analytical sensitivity, the van Gent-Pelzer significantly outperforms the van den Boogert and Bonants tests and is regarded as the test of choice when identifying S. endobioticum from resting spores. Tests regarded fit for purpose for routine testing of wart material and resting spore suspensions are proposed for the update of EPPO standard PM7/28(1) Synchytrium endobioticum
Credit Card service voor ISDN
No full textDit rapport beschrijft de specificatie en implementatie van de credit card service in een ISDN-omgeving.Electrical Engineering, Mathematics and Computer ScienceAutomatische Verkeerssysteme
Piled embankments with geosynthetic reinforcement: Numerical analysis of scale model tests
No full textIn the last few years, the CUR committee 159B has been working on the new Dutch Design Guideline for the design of piled embankments. To validate the guideline several field tests have been performed. From the field measurements is concluded that the design method is very conservative. Improving the design guideline will reduce the construction costs. To understand the physical behaviour of the piled embankment and to validate the theory, experimental scale tests have been performed. During these tests the load distribution, deformation and strains were measured. The results of the scale tests are analysed and published. To improve the understanding of the phenomenon arching and where possible, to confirm the observed load distributions and displacements, numerical analysis of the scale tests have been performed and reported in this thesis. The numerical analysis of the scale test is performed with Plaxis 3D Tunnel version 2.4 (Plaxis). The geometry of the Plaxis model is one quarter of the geometry of the scale test. This reduces the amount of elements and therefore the calculation time. In the scale test circular piles are applied. Circular geometry cannot be modelled in Plaxis, therefore the circular pile is mathematically converted to a square pile. The sand and granular material are modelled with Mohr Coulomb (MC) model and Hardening Soil (HS) model. The scale test is driven by applying top load and by drainage of the foam cushion. The top load is modelled as the measured equally distributed load on the embankment. To model the drainage of the foam cushion, the measured water pressure is assigned to the subsoil clusters in Plaxis by a water pressure head. From the Plaxis results can be concluded that arching is immediately found after the first drainage of the foam cushion. Increasing the top load and drainage of the foam cushion in Plaxis results in an increase of loads transferred to the pile by arching and GR, thus results in improvement of arching. The by Plaxis calculated tensile forces in the GR are concentrated in ‘tensile strips’ that lie on top and between adjacent piles. The largest displacement of the GR is found at the middle of four piles. The results of the Plaxis calculations are compared to the scale test results. The total load on the pile and water pressure in the foam cushion found with Plaxis are corresponding with the scale test results. During the first part of the test, the load distribution shows similar results as the measured load distribution. During the second part of the test the load transferred to the pile by arching is overestimated and the load transferred to the pile by the GR is underestimated. The displacement of the geosynthetic reinforcement calculated with Plaxis is underestimated compared to the scale test results. In general the results of the HS model are better than the MC model. By varying a number of parameters in the model, possible causes for the underestimated displacement are investigated. This research concludes that the stiffness of the foam cushion and the water pressure in the foam cushion does not have influence on the GR displacement. The vertical effective stresses are concentrated on and directly next to the pile and are relatively small between the piles. The internal friction angle does have a large influence on the geosynthetic reinforcement displacement, because when the internal friction angle is decreased, the arch decreases and the settlements increase. However, the measured geosynthetic reinforcement displacement from the scale test is still not found in the numerical results calculated in Plaxis.Geo-EngineeringCivil Engineering and Geoscience
Commentary: Wild psychometrics: Evidence for ‘general’ cognitive performance in wild New Zealand robins, Petroica longipes
No full textA commentary on
Wild psychometrics: Evidence for ‘general’ cognitive performance in wild New Zealand robins, Petroica longipes
by Shaw, R. C., Boogert, N. J., Clayton, N. S., and Burns, K. C. (2015). Anim. Behav. 109, 101–111. doi: 10.1016/j.anbehav.2015.08.00
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