Staff Publications

Staff Publications

  • external user (warningwarning)
  • Log in as
  • language uk
  • About

    '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.

    We have a manual that explains all the features 

Current refinement(s):

Records 1 - 20 / 35

  • help
  • print

    Print search results

  • export

    Export search results

  • alert
    We will mail you new results for this query: keywords==discrimination
Check title to add to marked list
Testing for disconnection and distance effects on physiological self-recognition within clonal fragments of Potentilla reptans
Chen, B. ; Vermeulen, P.J. ; During, H.J. ; Anten, N.P.R. - \ 2015
Frontiers in Plant Science 6 (2015). - ISSN 1664-462X - 9 p.
herb glechoma-hederacea - fragaria-chiloensis - nutrient availability - kin recognition - rooting volume - pot size - plant - integration - ramets - discrimination
Evidence suggests that belowground self-recognition in clonal plants can be disrupted between sister ramets by the loss of connections or long distances within a genet. However, these results may be confounded by severing connections between ramets in the setups. Using Potentilla reptans, we examined severance effects in a setup that grew ramet pairs with connections either intact or severed. We showed that severance generally reduced new stolon mass but had no effect on root allocation of ramets. However, it did reduce root mass of younger ramets of the pairs. We also explored evidence for physiological self-recognition with another setup that avoided severing connections by manipulating root interactions between closely connected ramets, between remotely connected ramets and between disconnected ramets within one genet. We found that ramets grown with disconnected neighbors had less new stolon mass, similar root mass but higher root allocation as compared to ramets grown with connected neighbors. There was no difference in ramet growth between closely connected- and remotely connected-neighbor treatments. We suggest that severing connections affects ramet interactions by disrupting their physiological integration. Using the second setup, we provide unbiased evidence for physiological self-recognition, while also suggesting that it can persist over long distances.
Loss of Olfactory Function and Nutritional Status in Vital Older Adults and Geriatric Patients
Toussaint, N. ; Roon, M. de; Campen, J.P.C.M. van; Kremer, S. ; Boesveldt, S. - \ 2015
Chemical Senses 40 (2015)3. - ISSN 0379-864X - p. 197 - 203.
mild cognitive impairment - odor identification - normative data - taste - malnutrition - smell - discrimination - dysfunction - prevalence - validation
The aim of this cross-sectional study was to assess the association of olfactory function and nutritional status in vital older adults and geriatric patients. Three hundred forty-five vital (mean age 67.1 years) and 138 geriatric older adults (mean age 80.9 years) were included. Nutritional status was assessed using the mini nutritional assessment-short form. The Sniffin’ Sticks was used to measure olfactory function. Eleven percentage of the vital older adults were at risk of malnutrition, whereas 60% of the geriatric participants were malnourished or at risk. Only 2% of the vital older adults were anosmic, compared with 46% of the geriatric participants. Linear regression demonstrated a significant association (P = 0.015) between olfactory function and nutritional status in the geriatric subjects. However, this association became insignificant after adjustment for confounders. Both crude and adjusted analysis in the vital older adults did not show a significant association. The results indicate that, in both groups of elderly, there is no direct relation between olfactory function and nutritional status. We suggest that a decline in olfactory function may still be considered as one of the risk-factors for malnutrition in geriatric patients—once co-occurring with other mental and/or physical problems that are more likely to occur in those patients experience.
Detection of sunflower oil in extra virgin olive oil by fast differential scanning calorimetry
Wetten, I.A. ; Herwaarden, A.W. ; Splinter, R. ; Boerrigter-Eenling, R. ; Ruth, S.M. van - \ 2015
Thermochimica Acta 603 (2015). - ISSN 0040-6031 - p. 237 - 243.
crystallization - discrimination - adulteration - polymers - tool - dsc
Extra virgin olive oil (EVOO) is an economically valuable product, due to its high quality and premium price. Therefore it is vulnerable for adulteration by means of the addition of cheaper vegetable oils. Differential scanning calorimetry (DSC) has been suggested as a fast technique for the detection of adulteration. However, measurements still take several hours. Fast DSC measurements take several minutes. Therefore this study investigates the applicability of fast DSC for the detection of sunflower oil (SFO) in EVOO. Nine EVOOs, five SFOs and three mixtures were analysed. Cooling curves of EVOO and SFO show one major exothermic peak. Because the cooling curves of EVOO and SFO are very similar they cannot be used for the detection of adulteration. Heating curves of EVOOs show two major endothermic peaks after slow cooling (-2 °C/s), heating curves of SFOs only one. Addition of SFO to EVOO caused a rapid decrease in the coldest endothermic peak and can therefore be used in the detection of adulteration of EVOO by SFO. Depending on the type of olive oil, the presence of 2–10% SFO can already be detected.
Aroma chemistry of African Oryza glaberrima and Oryza sativa rice and their interspecific hybrids
Cho, S. ; Nuijten, H.A.C.P. ; Shewfelt, R.L. ; Kays, S.J. - \ 2014
Journal of the Science of Food and Agriculture 94 (2014)4. - ISSN 0022-5142 - p. 727 - 735.
odor-active compounds - volatile components - fragrant rice - gc-ms - wine - headspace - discrimination - identification - origins - brown
BackgroundTo increase rice production in Africa, considerable research has focused on creating interspecific hybrids between African (Oryza glaberrima Steud.) and Asian (O. sativa L.) rice in an attempt to obtain the positive attributes of each in new cultivars. Since flavor is a key criterion in consumer acceptance of rice, as an initial inquiry we characterized and compared the aroma chemistry of selected cultivars of African O. sativa ssp. japonica, O. sativa ssp. indica, O. glaberrima, and their interspecific hybrids grown in West Africa, using gas chromatography-mass spectrometry, gas chromatography-olfactometry and descriptive sensory analysis. ResultsOf 41 volatiles identified across seven representative rice cultivars grown in West Africa, 3,5,5-trimethyl-2-cyclopenten-1-one, styrene, eucalyptol, linalool, myrtenal and l--terpineol had not been previously reported in rice. Thirty-three odor-active compounds were characterized. 4-Ethylphenol and (E,E)-2,4-heptadienal were unique to O. glaberrima, and pyridine, eucalyptol and myrtenal were described only in an interspecific hybrid. Descriptive sensory analysis indicated cooked grain', barny' and earthy' attributes were statistically different among the cultivars. ConclusionThe aroma chemistry data suggest that it should be possible to separate African cultivars into distinct flavor types thereby facilitating selection of new cultivars with superior flavor in African rice breeding programs. (c) 2013 Society of Chemical Industry
Food plant and herbivore host species affect the outcome of intrinsic competition among parasitoid larvae
Poelman, E.H. ; Gols, R. ; Gumovsky, A.V. ; Cortesero, A.M. ; Dicke, M. ; Harvey, J.A. - \ 2014
Ecological Entomology 39 (2014)6. - ISSN 0307-6946 - p. 693 - 702.
cotesia-rubecula hymenoptera - endoparasitoid wasps - insect parasitoids - heliothis-virescens - community structure - braconidae - superparasitism - discrimination - solitary - lepidoptera
1. In nature, several parasitoid species often exploit the same stages of a common herbivore host species and are able to coexist despite competitive interactions amongst them. Less is known about the direct effects of resource quality on intrinsic interactions between immature parasitoid stages. The present study is based on the hypothesis that variation in the quality or type of plant resources on which the parasitoids indirectly develop may be complementary and thus facilitate niche segregation favouring different parasitoids in intrinsic competition under different dietary regimes. 2. The present study investigated whether two herbivore species, the cabbage butterflies Pieris brassicae and Pieris rapae (Pieridae), and the quality of two important food plants, Brassica oleracea and Brassica nigra (Brassicaceae), affect the outcome of intrinsic competition between their primary larval endoparasitoids, the gregarious Cotesia glomerata (Braconidae) and the solitary Hyposoter ebeninus (Ichneumonidae). 3. Hyposoter ebeninus is generally an intrinsically superior competitor over C.¿glomerata. However, C.¿glomerata survived more antagonistic encounters with H.¿ebeninus when both developed in P.¿brassicae rather than in P.¿rapae caterpillars, and while its host was feeding on B.¿nigra rather than B.¿oleracea. Moreover, H.¿ebeninus benefitted from competition by its higher survival in multiparasitised hosts. 4. These results show that both plant and herbivore species mediate the battleground on which competitive interactions between parasitoids are played out and may affect the outcomes of these interactions in ways that enable parasitoids to segregate their niches. This in turn may promote coexistence among parasitoid species that are associated with the same herbivore host.
Differences in olfactory species recognition in the females of two Australian songbird species
Krause, E.T. ; Brummel, C. ; Kohlwey, S. ; Baier, M.C. ; Müller, C. ; Bonadonna, F. ; Caspers, B.A. - \ 2014
Behavioral Ecology and Sociobiology 68 (2014)11. - ISSN 0340-5443 - p. 1819 - 1827.
finches taeniopygia-guttata - zebra finches - odor recognition - kin recognition - wild - birds - nest - cues - discrimination - speciation
Although birds have recently been shown to possess olfactory abilities and to use chemical cues in communication, limited effort has been made to demonstrate the use of odorants in social contexts. Even less is known regarding the use of odorants in species recognition. The ability to recognize conspecifics should be more pronounced in social species. This study investigated the importance of olfactory cues in species recognition in females of two estrildid finch species with different levels of sociality. Combining odor preference tests with chemical analyses, we surveyed whether female zebra finches and diamond firetails are able to distinguish between the species based on volatile traits and whether individuals exhibit species-specific differences in body odorants. Zebra finches are more social than diamond firetails; nevertheless, both species have an overlapping distribution area. Applying an experimental Y-maze paradigm, we showed that zebra finches can use differences in their species odor fingerprints and displayed a significant preference for the odor of conspecifics over that of heterospecifics, whereas diamond firetails did not reveal a preference. Using gas chromatography and mass spectrometry, we demonstrated that body odorants of the two species were significantly different in relative composition. This finding demonstrates the potential importance of olfactory cues in species recognition, at least in social bird species. Even these two closely related species displayed remarkable differences in their responsiveness to similar chemical cues, which might be caused by species-specific differences in ecology, physiology, or evolution. Keywords Songbird . Zebra finch . Taeniopygia guttata . Diamond firetail . Stagonopleura guttata . Sociality . Olfaction . Smell . Scent . Olfactory fingerprint
Identifying Optimal Models to Represent Biochemical Systems
Apri, M. ; Gee, M. de; Mourik, S. van; Molenaar, J. - \ 2014
PLoS ONE 9 (2014)1. - ISSN 1932-6203 - 12 p.
parameter-estimation - optimization - reduction - discrimination - mechanisms - networks - pathways - receptor - designs
Biochemical systems involving a high number of components with intricate interactions often lead to complex models containing a large number of parameters. Although a large model could describe in detail the mechanisms that underlie the system, its very large size may hinder us in understanding the key elements of the system. Also in terms of parameter identification, large models are often problematic. Therefore, a reduced model may be preferred to represent the system. Yet, in order to efficaciously replace the large model, the reduced model should have the same ability as the large model to produce reliable predictions for a broad set of testable experimental conditions. We present a novel method to extract an “optimal” reduced model from a large model to represent biochemical systems by combining a reduction method and a model discrimination method. The former assures that the reduced model contains only those components that are important to produce the dynamics observed in given experiments, whereas the latter ensures that the reduced model gives a good prediction for any feasible experimental conditions that are relevant to answer questions at hand. These two techniques are applied iteratively. The method reveals the biological core of a model mathematically, indicating the processes that are likely to be responsible for certain behavior. We demonstrate the algorithm on two realistic model examples. We show that in both cases the core is substantially smaller than the full model.
A multiplex bead-based suspension array assay for interrogation of phylogenetically informative single nucleotide polymorphisms for Bacillus anthracis
Thierry, S. ; Hamidjaja, R.A. ; Girault, G. ; Lofstrom, C. ; Ruuls-van Stalle, E.M.F. ; Sylviane, D. - \ 2013
Journal of Microbiological Methods 95 (2013)3. - ISSN 0167-7012 - p. 357 - 365.
tandem-repeat analysis - large-scale - listeria-monocytogenes - pathogen detection - genotyping assays - dna - probes - discrimination - amplification - pcr
Single nucleotide polymorphisms (SNPs) are abundant in genomes of all species and represent informative DNA markers extensively used to analyze phylogenetic relationships between strains. Medium to high throughput, open methodologies able to test many SNPs in a minimum time are therefore in great need. By using the versatile Luminex (R) xTAG technology, we developed an efficient multiplexed SNP genotyping assay to score 13 phylogenetically informative SNPs within the genome of Bacillus anthracis. The Multiplex Oligonucleotide Ligation-PCR procedure (MOL-PCR) described by Deshpande et al., 2010 has been modified and adapted for simultaneous interrogation of 13 biallelic canonical SNPs in a 13-plex assay. Changes made to the originally published method include the design of allele-specific dual-priming-oligonucleotides (DPOs) as competing detection probes (MOLigo probes) and use of asymmetric PCR reaction for signal amplification and labeling of ligation products carrying SNP targets. These innovations significantly reduce cross-reactivity observed when initial MOLigo probes were used and enhance hybridization efficiency onto the microsphere array, respectively. When evaluated on 73 representative samples, the 13-plex assay yielded unambiguous SNP calls and lineage affiliation. Assay limit of detection was determined to be 2 ng of genomic DNA. The reproducibility, robustness and easy-of-use of the present method were validated by a small-scale proficiency testing performed between four European laboratories. While cost-effective compared to other singleplex methods, the present MOL-PCR method offers a high degree of flexibility and scalability. It can easily accommodate newly identified SNPs to increase resolving power to the canSNP typing of B. anthracis. (C) 2013 Elsevier B.V. All rights reserved.
Differentiation of specialty coffees by proton transfer reaction-mass spectrometry
Özdestan, Ö. ; Ruth, S.M. van; Alewijn, M. ; Koot, A.H. ; Romano, A. ; Cappelin, L. ; Biasioli, F. - \ 2013
Food Research International 53 (2013)1. - ISSN 0963-9969 - p. 433 - 439.
near-infrared spectroscopy - volatile organic-compounds - geographical origin - roasted coffee - ptr-ms - gas-chromatography - authentication - discrimination - products - identification
In the coffee sector a diversity of certifications is available, with the most well-known being organic and fair trade. Intrinsic markers of products may help to assure the authenticity of food products and complement administrative controls. In the present study 110 market coffees with special production traits were characterized by high sensitivity proton transfer reaction mass spectrometry (HS PTR-MS) and volatiles were tentatively identified by PTR-time of flight MS. Espresso coffees, Kopi Luwak coffee and organic coffees could be distinguished by their profiles of volatile compounds with the help of chemometrics. A PLS-DA classification model was estimated to classify the organic and regular coffees by their HS PTR-MS mass spectra. Cross validation showed correct prediction of 42 out of the 43 (98%) organic coffee samples and 63 out of the 67 (95%) regular coffee samples. Therefore, the presented strategy is a promising approach to rapid organic coffee authentication.
The 40-item Monell Extended Sniffin' Sticks Identification Test (MONEX-40)
Freiherr, J. ; Gordon, A.R. ; Alden, E.C. ; Ponting, A.L. ; Hernandez, M. ; Boesveldt, S. ; Lundstrom, J.N. - \ 2012
Journal of Neuroscience Methods 205 (2012)1. - ISSN 0165-0270 - p. 10 - 16.
odor-identification - olfactory function - normative data - discrimination - reliability - performance - dysfunction - thresholds - university - version
Background Most existing olfactory identification (ID) tests have the primary aim of diagnosing clinical olfactory dysfunction, thereby rendering them sub-optimal for experimental settings where the aim is to detect differences in healthy subjects’ odor ID abilities. Materials and methods We have developed an extended version of the olfactory ID subtest of the Sniffin’ Sticks test battery to better assess the variability in ID scores and thereby olfactory abilities of healthy, adult individuals. Twenty-four odorants, corresponding cue labels, and distractor labels were added to the existing 16-item Sniffin’ Sticks ID test to create the 40-item Monell Extended Sniffin’ Sticks Identification Test (MONEX-40). The MONEX-40 was administered to 259 healthy young subjects, of which 72 were retested on an average of 212 days (SD 112 days) later. Results The added odor items demonstrated good validity, as shown by a significant correlation of the results with the original 16-item ID test. In addition, the MONEX-40 achieved a significant test–retest and split-half reliability. Conclusions Taken together, these results suggest that the MONEX-40 is a reliable method for experimental assessment of odor ID ability in healthy, young individuals. Moreover, its use of a wider range of odors allows the experimenter to present subsets of the MONEX-40 within the same experiment while maintaining statistical power.
LaHMa: A landscape heterogeneity mapping method using hyper-temporal datasets
Bie, C.A.J.M. de; Nguyen, Thi Thu Ha ; Scarrott, R.G. ; Skidmore, A.K. - \ 2012
International Journal of Geographical Information Science 26 (2012)11. - ISSN 1365-8816 - p. 2177 - 2192.
ndvi time-series - fragmented landscapes - spatial heterogeneity - vegetation cover - avhrr - discrimination - productivity - agriculture - validation - parameters
A new quantitative method extracts a landscape heterogeneity map (LaHMa) from hyper-temporal remote-sensing data. The feature extraction method is data-driven, unbiased, and builds on the commonly used data reduction technique of Iterative Self-Organizing Data Analysis (ISODATA) clustering with the support of divergence separability indices. First, the relevant spatial-temporal variation in normalized difference vegetation index (NDVI) is classified through ISODATA clustering. Second, a series of prepared cluster maps are overlaid to examine and detect the frequency with which boundaries between clusters occur at the same location. This step identifies the boundary strength between clusters and detects spatial heterogeneity within them. Results of the method are explored for the typical agriculture-defined landscape of the Mekong delta, Vietnam, using NDVI-imagery time-series from SPOT-Vegetation and MODIS-Terra. The method extracts useful landscape heterogeneity features and can support land-cover mapping requiring information on fragmentation and land-cover gradients.
Effect of light quality on movement of Pterostichus melanarius (Coleoptera: Carabidae)
Allema, A.B. ; Rossing, W.A.H. ; Werf, W. van der; Heusinkveld, B.G. ; Bukovinszky, T. ; Steingröver, E.G. ; Lenteren, J.C. van - \ 2012
Journal of Applied Entomology 136 (2012)10. - ISSN 0931-2048 - p. 793 - 800.
red-light - patterns - beetles - discrimination - sensitivity - behavior - range - field - prey
Behaviour of nocturnal insects is routinely observed under red light, but it is unclear how the behaviour under red light compares to behaviour in complete darkness, or under a source of white light. Here, we measure movement behaviour of the nocturnal carabid beetle Pterostichus melanarius Illiger (Coleoptera: Carabidae) using camera recording under a near-infrared (nir), red or white radiation source. Red light significantly reduced movement speed in females similar to the effect of white light and different from nir. Also movement activity and pause length were affected by radiation source, with a significant difference between nir and white light, and with intermediate values in red light. The results presented here indicate that P. melanarius has different movement behaviour under the three radiation sources and suggest that nir rather than red radiation is most appropriate for measuring behaviour in total darkness. However, in the field total darkness is rare both because of natural light sources such as the moon and stars but increasingly also because of ecological light pollution, and therefore red light may still be of use for observing ecologically and practically relevant natural night-time behaviour.
Beliefs Contributing to HIV-related Stigma in African and Afro-Caribbean Communities in the Netherlands
Stutterheim, S.E. ; Bos, A.E.R. ; Kesteren, N.M.C. van; Shiripinda, I. ; Pryor, J.B. ; Bruin, M. de; Schaalma, H.P. - \ 2012
Journal of Community & Applied Social Psychology 22 (2012)2. - ISSN 1052-9284 - p. 470 - 484.
aids-related stigma - hiv/aids-related stigma - south-africa - intergroup contact - discrimination - attitudes - people - care - experiences - disclosure
Thirty years after the first diagnosis, people living with HIV (PLWH) around the world continue to report stigmatizing experiences. In this study, beliefs contributing to HIV-related stigma in African and Afro-Caribbean diaspora communities and their cultural context were explored through semi-structured interviews with HIV-positive (N¿=¿42) and HIV-negative (N¿=¿52) African, Antillean and Surinamese diaspora community members in the Netherlands. Beliefs that HIV is highly contagious, that HIV is a very severe disease, and that PLWH are personally responsible for acquiring their HIV infection were found to contribute to HIV-related stigma, as did the belief that PLWH are HIV-positive because they engaged in norm-violating behaviour such as promiscuity, commercial sex work, and, for Afro-Caribbean diaspora, also homosexuality. These beliefs were found to be exacerbated and perpetuated by cultural taboos on talking about HIV and sexuality. HIV-related stigma reduction interventions should focus on changing these beliefs and breaking cultural taboos on HIV and sexuality in a manner that is participatory and consistent with the current theory and empirical findings
HIV-related stigma in African and Afro-Caribbean communities in the Netherlands: Manifestations, consequences and coping
Stutterheim, S.E. ; Bos, A.E.R. ; Shiripinda, I. ; Bruin, M. de; Pryor, J.B. ; Schaalma, H.P. - \ 2012
Psychology and Health 27 (2012)4. - ISSN 0887-0446 - p. 395 - 411.
aids-related stigma - hiv/aids-related stigma - positive african - united-kingdom - experiences - discrimination - people - london - health - care
HIV-related stigma in African and Afro-Caribbean diaspora communities in the Netherlands was investigated. Interviews with HIV-positive and HIV-negative community members demonstrated that HIV-related stigma manifests as social distance, physical distance, words and silence. The psychological consequences of HIV-related stigma among those diagnosed with HIV reported were emotional pain, sadness, loneliness, anger, frustration and internalised stigma. The social consequences included decreased social network size, limited social support and social isolation, and resulted from not only enacted stigma but also self-imposed social withdrawal. Also, poor treatment adherence was a health-related consequence. People living with HIV employed both problem-focused and emotion-focused coping strategies to mitigate the negative consequences of stigma. Problem-focused coping strategies included selective disclosure, disengagement, affiliating with similar others, seeking social support and, to a lesser extent, activism. Emotion-focused strategies included distraction, positive reappraisal, religious coping, external attributions, disidentification and acceptance. HIV-related stigma clearly permeates African and Afro-Caribbean communities in the Netherlands, and should be targeted for intervention
Identifying plant species using mid-wave infrared (2.5-6µm) and thermal infrared (8-14µm) emissivity spectra
Ullah, S. ; Schlerf, M. ; Skidmore, A.K. ; Hecker, C. - \ 2012
Remote Sensing of Environment 118 (2012)4. - ISSN 0034-4257 - p. 95 - 102.
salt-marsh vegetation - hyperspectral data - biomass estimation - reflectance - discrimination - indexes - imagery - leaves - classification - spectroscopy
Plant species discrimination using remote sensing is generally limited by the similarity of their reflectance spectra in the visible, NIR and SWIR domains. Laboratory measured emissivity spectra in the mid infrared (MIR; 2.5µm-6µm) and the thermal infrared (TIR; 8µm-14µm) domain of different plant species, however, reveal significant differences. It is anticipated that with the advances in airborne and space borne hyperspectral thermal sensors, differentiation between plant species may improve. The laboratory emissivity spectra of thirteen common broad leaved species, comprising 3024 spectral bands in the MIR and TIR, were analyzed. For each wavelength the differences between the species were tested for significance using the one way analysis of variance (ANOVA) with the post-hoc Tukey HSD test. The emissivity spectra of the analyzed species were found to be statistically different at various wavebands. Subsequently, six spectral bands were selected (based on the histogram of separable pairs of species for each waveband) to quantify the separability between each species pair based on the Jefferies Matusita (JM) distance. Out of 78 combinations, 76 pairs had a significantly different JM distance. This means that careful selection of hyperspectral bands in the MIR and TIR (2.5µm-14µm) results in reliable species discrimination.
Effects of Visual Priming on Taste-Odor Interaction
Beilen, M. van; Bult, J.H.F. ; Renken, R. ; Stieger, M.A. ; Thumfart, S. ; Cornelissen, F. ; Kooijman, V.M. - \ 2011
PLoS ONE 6 (2011)9. - ISSN 1932-6203 - 9 p.
olfactory perception - sucrose solutions - perceived flavor - color - sweetness - discrimination - intensity - mixtures - texture - vision
Little is known about the influence of visual characteristics other than colour on flavor perception, and the complex interactions between more than two sensory modalities. This study focused on the effects of recognizability of visual (texture) information on flavor perception of odorized sweet beverages. Participants rated the perceived sweetness of odorized sucrose solutions in the presence or absence of either a congruent or incongruent visual context. Odors were qualitatively reminiscent of sweet foods (strawberry and caramel) or not (savoury). Visual context was either an image of the same sweet foods (figurative context) or a visual texture derived from this product (non-figurative context). Textures were created using a texture synthesis method that preserved perceived food qualities while removing object information. Odor-taste combinations were rated sweeter within a figurative than a non-figurative context. This behaviour was exhibited for all odor-taste combinations, even in trials without images, indicating sustained priming by figurative visual context. A non-figurative context showed a transient sweetening effect. Sweetness was generally enhanced most by the strawberry odor. We conclude that the degree of recognizability of visual information (figurative versus non-figurative), influences flavor perception differently. Our results suggest that this visual context priming is mediated by separate sustained and transient processes that are differently evoked by figurative and non-figurative visual contexts. These components operate independent of the congruency of the image-odor-taste combinations.
Investigation of interactions between texture and ortho- and retronasal olfactory stimuli using psychophysical and electrophysiological approaches
Roudnitzky, N. ; Bult, J.H.F. ; Wijk, R.A. de; Reden, J. ; Schuster, B. ; Hummel, T. - \ 2011
Behavioural Brain Research 216 (2011)1. - ISSN 0166-4328 - p. 109 - 115.
flavor perception - response alternatives - odor identification - swallowing process - release - mouth - taste - discrimination - integration - potentials
Flavor is a result of the complex combination of olfactory, gustatory and trigeminal sensations perceived during oral processing of foods, including thermal, painful, tactile and/or kinesthetic effects. Aim of this study was to better understand interactions between synchronous tactile (texture) and olfactory (odor) sensations, using a psychophysical and an electrophysiological approach. Texture stimuli were aliquots of lean milk and thickened lean milk. A butter aroma was presented either orthonasally or retronasally after oral processing and before swallowing the oral stimulus or in the absence of an oral stimulus. Eighteen subjects (11 women, 7 men, mean age 24 years), naïve to the expected effects, rated both odor and texture intensity of each stimulus. Event-related potentials (ERP) were obtained from five recording positions. For the psychophysical data, the presence of an oral stimulus increased odor intensity, irrespective of odor presentation route. For the electrophysiological data, both early and late chemosensory ERPs were affected by odor conditions, texture conditions, and their respective interaction. In conclusion: (1) perceptual interactions occurred between food texture and odor, with cross-modal interactions being found for both orthonasal and retronasal odor administration, and (2) these interactions between texture and odor occur at both primary-sensory and cognitive evaluative levels of stimulus processing. The temporal dimension plays then a critical role in the investigation of odor–texture interactions.
Diagnosis of the first cases of scrapie in Poland
Polak, M.P. ; Larska, M. ; Langeveld, J.P.M. ; Buschmann, A. ; Groschup, M.H. ; Zmudzinski, J.F. - \ 2010
The Veterinary Journal 186 (2010)1. - ISSN 1090-0233 - p. 47 - 52.
bovine spongiform encephalopathy - atypical scrapie - prion protein - monoclonal-antibodies - prp genotypes - sheep - nor98 - discrimination - strains - norway
This is the first report of cases of scrapie in Poland. The disease was an atypical phenotype, diagnosed in two aged sheep which were found dead. Brainstem samples from both animals were positive on the applied ELISA rapid test, while the confirmatory immunoblot indicated abnormal banding patterns of protease resistant prion protein (PrPres). The genotypes of these sheep were ALRQ/ALHQ and ALRQ/ALRR. The absence of premonitory clinical signs, the advanced age of the affected sheep, the higher concentration of PrPres in the cerebellum relative to the obex, the unusual banding profile of the prion protein and its relatively low resistance to proteolytic degradation confirmed the diagnosis of atypical scrapie (Nor98-like) in both cases
Does Wolbachia infection affect Trichogramma atopovirilia behaviour?
Almeida, R.P. de; Lenteren, J.C. van; Stouthamer, R. - \ 2010
Brazilian Journal of Biology 70 (2010)2. - ISSN 1519-6984 - p. 435 - 442.
biological-control - parasitoid wasp - searching behavior - host selection - minutum - hymenoptera - brassicae - discrimination - aleyrodidae - temperature
Unisexual Trichogramma forms have attracted much attention due to their potential advantages as biocontrol agents. Fitness studies have been performed and understanding the cost that Wolbachia may inflict on their hosts will help in deciding if Wolbachia infected (unisexual) forms are indeed better than sexual forms when used in biological control programmes. The influence of Wolbachia on the foraging behaviour (including walking activity and speed) of T. atopovirilia is reported in this paper. Temperature strongly affected T. atopovirilia female walking activity, but Wolbachia infected and uninfected females differed in none of the behavioural components that were measured such as walking activity and walking speed. Walking activity was highest at 25 ºC and differed significantly from that at 20 and 15 ºC. Trichogramma wasps were highly affected at 15 ºC. Behaviour analysis with females showed that female wasps spend most of the time on drilling + ovipositing on host eggs followed by host drumming and walking while drumming. The parasitism rate and number of offspring did not differ significantly between infected and cured Trichogramma females. Biological control implications of these findings are discussed.
Quantification of Eimeria acervulina in faeces of broilers: Comparison of McMaster oocyst counts from 24 h faecal collections and single droppings to real-time PCR from cloacal swabs
Velkers, F.C. ; Blake, D.P. ; Graat, E.A.M. ; Vernooij, J.C.M. ; Bouma, A. ; Jong, M.C.M. de; Stegeman, J.A. - \ 2010
Veterinary Parasitology 169 (2010)1-2. - ISSN 0304-4017 - p. 1 - 7.
polymerase-chain-reaction - anticoccidial drugs - avian coccidiosis - discrimination - vaccination - resistance - chickens - litter - spp. - fowl
Coccidiosis is an economically important disease in chickens, caused by infection with Eimeria species parasites. Diagnosis of coccidiosis is frequently based on oocyst enumeration in pooled faecal samples or litter. In studies on infection dynamics and for monitoring in the field, samples from individual chickens may be more appropriate as these support the determination of infection status of individual birds and more accurately reflect oocyst output at time of sampling. Faecal samples from individual birds can be collected, but the counting procedure limits the number of samples that can be processed and unequivocal microscopic differentiation between Eimeria species is very difficult. A test that overcomes these drawbacks would improve efficiency and quality of the diagnosis. The aim of this study was to compare two methods for Eimeria oocyst quantification in samples from individual birds. A real-time PCR that quantifies oocysts in cloacal swabs (qPCR) and oocyst counts in single droppings were compared to the standard procedure of oocyst counts in bulked 24 h faeces. Faecal samples were collected daily from 30 broiler chickens, inoculated with different doses of Eimeria acervulina. The three techniques produced comparable oocyst counts for all inoculation doses. Single dropping counts are applicable for small sample sizes and when a single Eimeria species is used. For larger sample sizes qPCR is preferable as it can be carried out on samples that have been frozen for storage. Furthermore, qPCR can identify and quantify different Eimeria species, which makes it a valuable diagnostic tool for field or experimental work
Check title to add to marked list
<< previous | next >>

Show 20 50 100 records per page

Please log in to use this service. Login as Wageningen University & Research user or guest user in upper right hand corner of this page.