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 

Records 1 - 14 / 14

  • help
  • print

    Print search results

  • export

    Export search results

  • alert
    We will mail you new results for this query: q=Ramsey
Check title to add to marked list
Acute effects of ∆9-tetrahydrocannabinol (THC) on resting state brain function and their modulation by COMT genotype
Bossong, Matthijs G. ; Hell, Hendrika H. van; Schubart, Chris D. ; Saane, Wesley van; Iseger, Tabitha A. ; Jager, Gerry ; Osch, Matthias J.P. van; Jansma, J.M. ; Kahn, René S. ; Boks, Marco P. ; Ramsey, Nick F. - \ 2019
European Neuropsychopharmacology 29 (2019)6. - ISSN 0924-977X - p. 766 - 776.
Arterial spin labelling - Cannabis - Catechol-methyl-transferase (COMT) - Delta9-tetrahydrocannabinol (THC) - Resting state connectivity - Salience

Cannabis produces a broad range of acute, dose-dependent psychotropic effects. Only a limited number of neuroimaging studies have mapped these effects by examining the impact of cannabis on resting state brain neurophysiology. Moreover, how genetic variation influences the acute effects of cannabis on resting state brain function is unknown. Here we investigated the acute effects of ∆9-tetrahydrocannabinol (THC), the main psychoactive constituent of cannabis, on resting state brain neurophysiology, and their modulation by catechol-methyl-transferase (COMT) Val158Met genotype. Thirty-nine healthy volunteers participated in a pharmacological MRI study, where we applied Arterial Spin Labelling (ASL) to measure perfusion and functional MRI to assess resting state connectivity. THC increased perfusion in bilateral insula, medial superior frontal cortex, and left middle orbital frontal gyrus. This latter brain area showed significantly decreased connectivity with the precuneus after THC administration. THC effects on perfusion in the left insula were significantly related to subjective changes in perception and relaxation. These findings indicate that THC enhances metabolism and thus neural activity in the salience network. Furthermore, results suggest that recruitment of brain areas within this network is involved in the acute effects of THC. Resting state perfusion was modulated by COMT genotype, indicated by a significant interaction effect between drug and genotype on perfusion in the executive network, with increased perfusion after THC in Val/Met heterozygotes only. This finding suggests that prefrontal dopamine levels are involved in the susceptibility to acute effects of cannabis.

Bioactive tannins in forage legumes: Myths, Ignorance and Aspirations
Mueller-Harvey, I. ; Ramsey, Aina ; Fryganas, Christos ; Ropiak, Honorate ; Drake, Chris ; Ortiz, Marina Mora ; Smith, Lydia M.J. ; Skot, L. ; Malisch, Carsten ; Luescher, Andreas ; Kempf, Katharina ; Kolliker, R. ; Desrues, Olivier ; Williams, Andrew R. ; Thamsborg, S.M. ; Azuhnwi, Blasius N. ; Quijada, J.N. ; Hoste, H. ; Girard, M. ; Grosse Brinkhaus, A. ; Dohme-Meier, F. ; Bee, G. ; Nguyen, T.H. ; Pellikaan, W.F. ; Copani, Giuseppe ; Niderkorn, Vincent ; Engstrom, Marica ; Salminen, J.P. ; Wilkinson, Ian ; Totterdell, Paul ; Waghorn, G.C. - \ 2015
Tannin-containing legumes have attracted much interest due to their animal health and nutritional benefits. Although several tannins are anti-nutritional, a few can generate valuable benefits for controlling parasitic nematodes that are resistant to anthelmintic drugs, for improving protein utilization by ruminants and fatty acid profiles in meat and milk products and for reducing greenhouse gases. A 5% dietary maximum limit of tannins has been suggested, but information on structure-activity relationships are essential in order to fully exploit the potential of these natural plant compounds. Breeders also require guidelines and screening tools for optimal tannin compositions, and farmers require tannin-containing forages that provide consistent results.

Plants vary in tannin contents and composition depending on species, variety and growing conditions. Recent research in Europe (‘LegumePlus' and other projects) has focused on new tools for analyzing soluble and insoluble tannins in plants, silages and digesta. This involved isolating different types of tannin standards from a wide range of different plants and thiolysis to assess their purity and composition. We also developed new UPLC-MS/MS, NIR- and NMR-analysis methods and tested tannin-protein interactions. Agronomists and plant breeders assembled germplasm collections, identified sainfoin-specific markers, and strategies for weed control. Ruminant nutritionists studied in vitro and in vivo fermentations, N-balances and the quality of meat and milk products. Parasitologists explored the anti-parasitic properties using a wide range of different tannin types.

The presentation will summarize current knowledge and conclude with a wishlist for ‘ideal' tannin-containing forages. It will emphasize that robust and stable tannin concentrations and compositions are required in addition to high yield, good weed suppression and resistance to climatic stress.
The endocannabinoid system and emotional processing: A pharmacological fMRI study with Delta 9-tetrahydrocannabinol
Bossong, M.G. ; Hell, H.H. van; Jager, G. ; Kahn, R.S. ; Ramsey, N.F. ; Jansma, J.M. - \ 2013
European Neuropsychopharmacology 23 (2013)12. - ISSN 0924-977X - p. 1687 - 1697.
cb1 cannabinoid receptors - happy facial expressions - healthy-volunteers - antagonist rimonabant - major depression - memory function - functional mri - amygdala - brain - involvement
Various psychiatric disorders such as major depression are associated with abnormalities in emotional processing. Evidence indicating involvement of the endocannabinoid system in emotional processing, and thus potentially in related abnormalities, is increasing. In the present study, we examined the role of the endocannabinoid system in processing of stimuli with a positive and negative emotional content in healthy volunteers. A pharmacological functional magnetic resonance imaging (fMRI) study was conducted with a placebo-controlled, cross-over design, investigating effects of the endocannabinoid agonist Delta 9-tetrahydrocannabinol (THC) on brain function related to emotional processing in 11 healthy subjects. Performance and brain activity during matching of stimuli with a negative ('fearful faces') or a positive content ('happy faces') were assessed after placebo and THC administration. After THC administration, performance accuracy was decreased for stimuli with a negative but not for stimuli with a positive emotional content. Our task activated a network of brain regions including amygdala, orbital frontal gyrus, hippocampus, parietal gyrus, prefrontal cortex, and regions in the occipital cortex. THC interacted with emotional content, as activity in this network was reduced for negative content, while activity for positive content was increased. These results indicate that THC administration reduces the negative bias in emotional processing. This adds human evidence to support the hypothesis that the endocannabinoid system is involved in modulation of emotional processing. Our findings also suggest a possible role for the endocannabinoid system in abnormal emotional processing, and may thus be relevant for psychiatric disorders such as major depression. (C) 2013 Elsevier B.V. and ECNP. All rights reserved.
Default Mode Network in the Effects of ¿9-Tetrahydrocannabinol (THC) on Human Executive Function
Bossong, M.G. ; Jansma, J.M. ; Hell, H.H. van; Jager, G. ; Kahn, R.S. ; Ramsey, N.F. - \ 2013
PLoS ONE 8 (2013)7. - ISSN 1932-6203 - 10 p.
deficit hyperactivity disorder - working-memory - endocannabinoid system - healthy-volunteers - prefrontal cortex - synaptic plasticity - error awareness - brain-function - neural basis - fmri
Evidence is increasing for involvement of the endocannabinoid system in cognitive functions including attention and executive function, as well as in psychiatric disorders characterized by cognitive deficits, such as schizophrenia. Executive function appears to be associated with both modulation of active networks and inhibition of activity in the default mode network. In the present study, we examined the role of the endocannabinoid system in executive function, focusing on both the associated brain network and the default mode network. A pharmacological functional magnetic resonance imaging (fMRI) study was conducted with a placebo-controlled, cross-over design, investigating effects of the endocannabinoid agonist ¿9-tetrahydrocannabinol (THC) on executive function in 20 healthy volunteers, using a continuous performance task with identical pairs. Task performance was impaired after THC administration, reflected in both an increase in false alarms and a reduction in detected targets. This was associated with reduced deactivation in a set of brain regions linked to the default mode network, including posterior cingulate cortex and angular gyrus. Less deactivation was significantly correlated with lower performance after THC. Regions that were activated by the continuous performance task, notably bilateral prefrontal and parietal cortex, did not show effects of THC. These findings suggest an important role for the endocannabinoid system in both default mode modulation and executive function. This may be relevant for psychiatric disorders associated with executive function deficits, such as schizophrenia and ADHD
Tentative Evidence for Striatal Hyperactivity in Adolescent Cannabis-Using Boys: A Cross-Sectional Multicenter fMRI Study
Jager, G. ; Block, R.I. ; Luijten, M. ; Ramsey, N.F. - \ 2013
Journal of Psychoactive Drugs 45 (2013)2. - ISSN 0279-1072 - p. 156 - 167.
brain-development - reward circuitry - activation - responsivity - anticipation - behavior - nucleus
Adolescents' risk-taking behavior has been linked to a maturational imbalance between reward (“go”) and inhibitory-control (“stop”)-related brain circuitry. This may drive adolescent drug-taking, such as cannabis use. In this study, we assessed the non-acute effects of adolescent cannabis use on reward-related brain function. We performed a two-site (United States and Netherlands; pooled data) functional magnetic resonance imaging (fMRI) study with a cross-sectional design. Twenty-one abstinent but frequent cannabis-using boys were compared with 24 non-using peers on reward-related brain function, using a monetary incentive delay task with fMRI. Focus was on anticipatory and response stages of reward and brain areas critically involved in reward processing like the striatum. Performance in users was normal. Region-of-interest analysis indicated striatal hyperactivity during anticipatory stages of reward in users. Intriguingly, this effect was most pronounced during non-rewarding events. Striatal hyperactivity in adolescent cannabis users may signify an overly sensitive motivational brain circuitry. Frequent cannabis use during adolescence may induce diminished ability to disengage the motivational circuit when no reward can be obtained. This could strengthen the search for reinforcements like drugs of abuse, even when facing the negative (non-rewarding) consequences.
THC reduces the anticipatory nucleus accumbens response to reward in subjects with a nicotine addiction
Jansma, J.M. ; Hell, H.H. van; Vanderschuren, L.J.M.J. ; Bossong, M.G. ; Jager, G. ; Kahn, R.S. ; Ramsey, N.F. - \ 2013
Translational Psychiatry 3 (2013). - ISSN 2158-3188 - 10 p.
endogenous cannabinoid anandamide - increasing monetary reward - endocannabinoid system - drug-addiction - cb1 receptors - brain - dependence - rats - inhibition - humans
Recent evidence has implicated the endocannabinoid (eCB) system in nicotine addiction. The eCB system also has an important role in reward mechanisms, and nicotine addiction has been associated with aberrant reward processing. Motivated by this evidence, we tested the hypothesis that eCB modulation of reward processing is altered in subjects with a nicotine addiction (NAD). For this purpose, we compared reward-related activity in NAD with healthy controls (HC) in a pharmacological magnetic resonance imaging (MRI) study using ¿9-tetrahydrocannabinol (THC) administration to challenge the eCB system. Eleven HC and 10 NAD participated in a 3-T functional MRI (fMRI) study with a double-blind, cross-over, placebo-controlled design, using a Monetary Incentive Delay (MID) paradigm with three reward levels. Reward activity in the nucleus accumbens (NAcc) and caudate putamen during anticipation and feedback of reward was compared after THC and placebo. fMRI results indicated a significant reduction of reward anticipation activity in the NAcc in NAD after THC administration, which was not present in HC. This is indicated by a significant group by drug by reward interaction. Our data show that THC significantly reduces the NAcc response to monetary reward anticipation in NAD. These results suggest that nicotine addiction is associated with altered eCB modulation of reward processing in the NAcc. This study adds important human data to existing evidence implicating the eCB system in nicotine addiction.
Effects of ¿9-Tetrahydrocannabinol Administration on human encoding and recall memory function: a pharmacological fMRI study
Bossong, M.G. ; Jager, G. ; Hell, H.H. van; Zuurman, L. ; Jansma, J.M. ; Mehta, M.A. ; Gerven, J. van; Kahn, R.S. ; Ramsey, N.F. - \ 2012
Journal of Cognitive Neuroscience 24 (2012)3. - ISSN 0898-929X - p. 588 - 599.
long-term-memory - impairs spatial memory - medial temporal-lobe - recognition memory - episodic retrieval - prefrontal cortex - smoked marijuana - semantic memory - oral delta(9)-tetrahydrocannabinol - healthy-volunteers
Deficits in memory function are an incapacitating aspect of various psychiatric and neurological disorders. Animal studies have recently provided strong evidence for involvement of the endocannabinoid (eCB) system in memory function. Neuropsychological studies in humans have shown less convincing evidence but suggest that administration of cannabinoid substances affects encoding rather than recall of information. In this study, we examined the effects of perturbation of the eCB system on memory function during both encoding and recall. We performed a pharmacological MRI study with a placebo-controlled, crossover design, investigating the effects of ¿9-tetrahydrocannabinol (THC) inhalation on associative memory-related brain function in 13 healthy volunteers. Performance and brain activation during associative memory were assessed using a pictorial memory task, consisting of separate encoding and recall conditions. Administration of THC caused reductions in activity during encoding in the right insula, the right inferior frontal gyrus, and the left middle occipital gyrus and a network-wide increase in activity during recall, which was most prominent in bilateral cuneus and precuneus. THC administration did not affect task performance, but while during placebo recall activity significantly explained variance in performance, this effect disappeared after THC. These findings suggest eCB involvement in encoding of pictorial information. Increased precuneus activity could reflect impaired recall function, but the absence of THC effects on task performance suggests a compensatory mechanism. These results further emphasize the eCB system as a potential novel target for treatment of memory disorders and a promising target for development of new therapies to reduce memory deficits in humans
Effects of ¿9-Tetrahydrocannabinol on human working memory function
Bossong, M.G. ; Jansma, J.M. ; Hell, H.H. van; Jager, G. ; Oudman, E. ; Saliasi, E. ; Kahn, R.S. ; Ramsey, N.F. - \ 2012
Biological Psychiatry 71 (2012)8. - ISSN 0006-3223 - p. 693 - 699.
dorsolateral prefrontal cortex - catechol-o-methyltransferase - endogenous cannabinoids - genetic-variation - brain-function - schizophrenia - dysfunction - fmri - mri - cognition
Background Evidence indicates involvement of the endocannabinoid (eCB) system in both the pathophysiology of schizophrenia and working memory (WM) function. Additionally, schizophrenia patients exhibit relatively strong WM deficits. These findings suggest the possibility that the eCB system is also involved in WM deficits in schizophrenia. In the present study, we examined if perturbation of the eCB system can induce abnormal WM activity in healthy subjects. Methods A pharmacological functional magnetic resonance imaging study was conducted with a placebo-controlled, cross-over design, investigating effects of the eCB agonist ¿9-tetrahydrocannabinol on WM function in 17 healthy volunteers, by means of a parametric Sternberg item-recognition paradigm with five difficulty levels. Results Performance accuracy was significantly reduced after ¿9-tetrahydrocannabinol. In the placebo condition, brain activity increased linearly with rising WM load. ¿9-Tetrahydrocannabinol administration enhanced activity for low WM loads and reduced the linear relationship between WM load and activity in the WM system as a whole and in left dorsolateral prefrontal cortex, inferior temporal gyrus, inferior parietal gyrus, and cerebellum in particular. Conclusions ¿9-Tetrahydrocannabinol enhanced WM activity network-wide for low loads, while reducing the load-dependent response for increasing WM loads. These results indicate that a challenged eCB system can induce both abnormal WM activity and WM performance deficits and provide an argument for the possibility of eCB involvement in WM deficits in schizophrenia
Involvement of the endocannabinoid system in reward processing in the human brain
Hell, H.H. van; Jager, G. ; Bossong, M.G. ; Brouwer, A. ; Jansma, J.M. ; Zuurman, L. ; Gerven, J. van; Kahn, R.S. ; Ramsey, N.F. - \ 2012
Psychopharmacology 219 (2012)4. - ISSN 0033-3158 - p. 981 - 990.
acute oral delta(9)-tetrahydrocannabinol - cannabinoid cb1 receptors - healthy-volunteers - clinical-research - dopamine release - decision-making - human striatum - neural-basis - thc - delta-9-tetrahydrocannabinol
Rationale Disturbed reward processing in humans has been associated with a number of disorders, such as depression, addiction, and attention-deficit hyperactivity disorder. The endocannabinoid (eCB) system has been implicated in reward processing in animals, but in humans, the relation between eCB functioning and reward is less clear. Objectives The current study uses functional magnetic resonance imaging (fMRI) to investigate the role of the eCB system in reward processing in humans by examining the effect of the eCB agonist ¿9-tetrahydrocannabinol (THC) on reward-related brain activity. Methods Eleven healthy males participated in a randomized placebo-controlled pharmacological fMRI study with administration of THC to challenge the eCB system. We compared anticipatory and feedback-related brain activity after placebo and THC, using a monetary incentive delay task. In this task, subjects are notified before each trial whether a correct response is rewarded (“reward trial”) or not (“neutral trial”). Results Subjects showed faster reaction times during reward trials compared to neutral trials, and this effect was not altered by THC. THC induced a widespread attenuation of the brain response to feedback in reward trials but not in neutral trials. Anticipatory brain activity was not affected. Conclusions These results suggest a role for the eCB system in the appreciation of rewards. The involvement of the eCB system in feedback processing may be relevant for disorders in which appreciation of natural rewards may be affected such as addiction
Endocannabinoid involvement in reward and impulsivity in addiction
Hell, H.H. van - \ 2011
Rijksuniversiteit Utrecht. Promotor(en): N.F. Ramsey, co-promotor(en): Kees de Graaf. - Utrecht : Universiteit Utrecht - ISBN 9789053354704
Addiction is one of the most disabling diseases in the world. An important neurotransmitter system that has recently been implicated in addiction is the endocannabinoid system. The endocannabinoid system consists of cannabinoid receptors and endocannabinoid ligands that work on these receptors. Animal studies have shown that blocking the cannabinoid system prevents relapse to addiction, while activating the cannabinoid system with an agonist evokes relapse. Still, the involvement of the endocannabinoid system in addiction in humans remains unclear. The current thesis aimed to clarify the role of the endocannabinoid system in reward processing in nicotine addiction in humans. Brain function during reward processing was assessed using functional Magnetic Resonance Imaging (fMRI). In the first study described in this thesis, we have shown that both chronic nicotine and cannabis use attenuates reward-related brain activity in the nucleus accumbens, a brain area well known for its involvement in reward processing. Next, the endocannabinoid system was challenged using the partial cannabinoid agonist THC, the main psychoactive constituent of cannabis. When comparing nicotine users with non-using controls, we showed that a THC challenge did not affect reward processing in the nucleus accumbens in controls, while it was attenuated in nicotine users. Thus, altered reward processing as is found in nicotine addiction is associated with increased sensitivity of the cannabinoid system. In contrast, the endocannabinoid system seems to play a limited role in normal reward processing. Together, these data indicate that the endocannabinoid system is involved in addiction, and possibly other diseases in which reward processing is impaired, such as depression and ADHD
Evidence for involvement of the insula in the psychotropic effects of THC in humans: a double-blind, randomized pharmacological MRI study
Hell, H.H. van; Bossong, M.G. ; Jager, G. ; Kristo, G. ; Osch, M.J.P. ; Zelaya, F. ; Kahn, R.S. ; Ramsey, N.F. - \ 2011
International Journal of Neuropsychopharmacology 14 (2011)10. - ISSN 1461-1457 - p. 1377 - 1388.
cerebral-blood-flow - low-frequency fluctuation - central-nervous-system - resting-state fmri - neural-basis - anterior insula - healthy-volunteers - marijuana smoking - functional mri - cannabis use
The main reason for recreational use of cannabis is the ‘high’, the primary psychotropic effect of ¿9-tetrahydrocannabinol (THC). This psychoactive compound of cannabis induces a range of subjective, physical and mental reactions. The effect on heart rate is pronounced and complicates bloodflow-based neuroimaging of psychotropic effects of THC. In this study we investigated the effects of THC on baseline brain perfusion and activity in association with the induction of ‘feeling high’. Twenty-three subjects participated in a pharmacological MRI study, where we applied arterial spin labelling (ASL) to measure perfusion, and resting-state functional MRI to assess blood oxygen level-dependent signal fluctuation as a measure of baseline brain activity. Feeling high was assessed with a visual analogue scale and was compared to the imaging measures. THC increased perfusion in the anterior cingulate cortex, superior frontal cortex, and insula, and reduced perfusion in the post-central and occipital gyrus. Baseline brain activity was altered, indicated by increased amplitude of fluctuations in resting-state functional MRI signal after THC administration in the insula, substantia nigra and cerebellum. Perfusion changes in frontal cortex were negatively correlated with ratings of feeling high, suggesting an interaction between cognitive control and subjective effects of THC. In conclusion, an acute THC challenge altered baseline brain perfusion and activity, especially in frontal brain areas involved in cognitive and emotional processes, and the insula, associated with interoceptive awareness. These changes may represent the THC-induced neurophysiological correlates of feeling high. The alterations in baseline brain perfusion and activity also have relevance for studies on task-related effects of THC on brain function.
Modern remote sensing for environmental monitoring of landscape states and trajectories
Zimmermann, N.E. ; Washington-Allen, R.A. ; Ramsey, R.D. ; Schaepman, M.E. ; Mathys, L. ; Koetz, B. ; Kneubühler, M. ; Edwards, T.C. - \ 2007
In: A Changing World : Challenges for Landscape Research / Kienast, F., Wildi, O., Ghosh, S., Dordrecht : Springer (Landscape Series 8) - ISBN 9789048123902 - p. 65 - 91.
Novel species of Cylindrocarpon (Neonectria) and Campylocarpon gen. nov. associated with black foot disease of grapevines (Vitis spp.).
Halleen, F. ; Schroers, H.J. ; Groenewald, J.Z. ; Crous, P.W. - \ 2004
Studies in Mycology 50 (2004)2. - ISSN 0166-0616 - p. 431 - 455.
ribosomal dna-sequences - phylogenetic-relationships - anamorphs - fusarium - hypocreales - nectria - fungus - bionectriaceae - identification - destructans
Four Cylindrocarpon or Cylindrocarpon-like taxa isolated from asymptomatic or diseased Vitis vinifera plants in nurseries and vineyards of South Africa, New Zealand, Australia, and France were morphologically and phylogenetically compared with other Neonectria/Cylindrocarpon taxa. Sequences of the partial nuclear large subunit ribosomal DNA (LSU rDNA), internal transcribed spacers 1 and 2 of the rDNA including the 5.8S rDNA gene (ITS), and partial -tubulin gene introns and exons were used for phylogenetic inference. Neonectria/ Cylindrocarpon species clustered in mainly three groups. One monophyletic group consisted of three subclades comprising (i) members of the Neonectria radicicola/Cylindrocarpon destructans complex, which contained strains isolated from grapevines in South Africa, New Zealand, and France; (ii) a Neonectria/Cylindrocarpon species isolated from grapevines in South Africa, Canada (Ontario), Australia (Tasmania), and New Zealand, described here as Cylindrocarpon macrodidymum; and (iii) an assemblage of species closely related to strains identified as Cylindrocarpon cylindroides, the type species of Cylindrocarpon. This monophyletic group excluded two other groups, which comprised (i) members of the Neonectria mammoidea complex, with anamorphs characterised by curved macroconidia, violet or purple pigments in cultures of most of its members, and lack of microconidia and chlamydospores; and (ii) two undescribed Cylindrocarpon-like species, both from grapevines in South Africa. The latter two clades formed a paraphyletic group in LSU rDNA analysis but were supported as a monophyletic group in ITS and -tubulin gene analysis. Strains of the Neonectria radicicola/Cylindrocarpon destructans complex isolated from grapevines matched C. destructans in morphology and DNA sequences. Cylindrocarpon macrodidymum formed micro- and macroconidia, but rarely formed chlamydospores. Its mostly 3-septate macroconidia were more or less straight, minutely widening towards the tip, and had an apical cell slightly bent to one side. Its teleomorph, Neonectria macrodidyma, was obtained in mating experiments, and was characterised by smooth to finely warted ascospores, smooth to finely warted perithecia, and moderately sized angular to subglobose cells in the outer region of the perithecial wall. The other two undescribed Cylindrocarpon-like species mentioned above were characterised by mostly 3-5-septate, curved macroconidia, and by the lack of microconidia. Both species differed from members of the Neonectria mammoidea group by brownish colonies and by brownish hyphal strands formed in the aerial mycelium. For these species a new genus, Campylocarpon gen. nov., is proposed. It comprises the new species Campylocarpon fasciculare and Campylocarpon pseudofasciculare, respectively. Inoculation of 6-mo-old potted grapevine rootstocks (cv. Ramsey) with selected isolates of Cylindrocarpon destructans, Neonectria macrodidyma, Campylocarpon fasciculare, and Campylocarpon pseudofasciculare resulted in a reduced root and shoot mass of inoculated plants and appearance of symptoms typical of black foot disease.
Dynamic modelling of pollution abatement in a CGE framework
Dellink, R.B. ; Hofkes, M.W. ; Ierland, E.C. van; Verbruggen, H. - \ 2004
Economic Modelling 21 (2004)6. - ISSN 0264-9993 - p. 965 - 989.
climate-change - policy
This paper deals with the specification of pollution abatement in dynamic computable general equilibrium (CGE) models and analyses the dynamic feedback mechanisms between economy and abatement in the context of environmental policy. A Ramsey-type economic model is presented, in which bottom-up technical and economic information on abatement techniques is integrated in a top-down dynamic CGE context. The practical suitability of the specification is illustrated by an empirical application for climate change and acidification in the Netherlands. The results show that a mixture of some slowdown of economic growth, a substantial restructuring of the economy and implementation of most technical abatement measures is optimal. (C) 2003 Elsevier B.V. All rights reserved.
Check title to add to marked list

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.