Longer Oral Exposure with Modified Sham Feeding Does Not Slow Down Gastric Emptying of Low- and High-Energy-Dense Gastric Loads in Healthy Young Men
Wijlens, G.M. ; Erkner, A. ; Mars, M. ; Graaf, C. de - \ 2015
The Journal of Nutrition 145 (2015)2. - ISSN 0022-3166 - p. 365 - 371.
food-intake - appetite - stimulation - fat - responses - humans - satiation - ghrelin - liquids - volume
Background: A long oral exposure to food and a high-energy density of food are shown to increase satiety feelings. The effect of energy density is predominantly caused by an inhibition of gastric emptying. It is hypothesized that prolonging oral exposure may have an additional effect on this inhibition of gastric emptying. However, little human data are available to support this hypothesis. Objective: The objective was to assess the effect of oral exposure duration to food on gastric emptying rate of gastric loads (GLs) low and high in energy density and on satiety feelings. Methods: Twenty-six healthy men (22 ± 3 y, 23 ± 1 kg/m2) participated in a randomized crossover trial with 4 treatments and a control. Treatments consisted of either 1- or 8-min modified sham feeding (MSF) of cake, and a GL of either 100 or 700 kcal infused in the stomach via a nasogastric tube (500 mL, 62.5 mL/min). The control consisted of no MSF and a GL of 500 mL of water. Gastric emptying rate was assessed with a 13C breath test. Breath samples and satiety feelings were collected at fixed time points until 90 min after start of the treatment. Results: Gastric emptying rate and satiety feelings were not affected by duration of MSF (P = 0.27). However, the 700-kcal GL treatments slowed gastric emptying [41% lower area under the curve (AUC)] and increased satiety feelings (22–31% higher AUC) compared with the 100-kcal GL treatments (P <0.001). No interaction between MSF duration and energy density of GL was found (P = 0.44). Conclusions: Higher gastric energy density inhibited gastric emptying and increased satiety feelings in healthy young men. However, prolonging oral exposure to food did not have an additional effect. This study provides more insight in satiety regulation. This trial was registered at trialregister.nl as NTR3601.
Nondestructive estimates of above-ground biomass using terrestrial laser scanning
Calders, K. ; Newnham, G. ; Burt, A. ; Murphy, S. ; Raumonen, P. ; Herold, M. ; Culvenor, D. ; Avitabile, V. ; Disney, M. ; Armston, J. ; Kaasalainen, M. - \ 2015
Methods in Ecology and Evolution 6 (2015)2. - ISSN 2041-210X - p. 198 - 208.
carbon-density - tree - lidar - models - equations - systems - volume - stocks
Allometric equations are currently used to estimate above-ground biomass (AGB) based on the indirect relationship with tree parameters. Terrestrial laser scanning (TLS) can measure the canopy structure in 3D with high detail. In this study, we develop an approach to estimate AGB from TLS data, which does not need any prior information about allometry. We compare these estimates against destructively harvested AGB estimates and AGB derived from allometric equations. We also evaluate tree parameters, diameter at breast height (DBH) and tree height, estimated from traditional field inventory and TLS data. Tree height, DBH and AGB data are collected through traditional forest inventory, TLS and destructive sampling of 65 trees in a native Eucalypt Open Forest in Victoria, Australia. Single trees are extracted from the TLS data and quantitative structure models are used to estimate the tree volume directly from the point cloud data. AGB is inferred from these volumes and basic density information and is then compared with the estimates derived from allometric equations and destructive sampling. AGB estimates derived from TLS show a high agreement with the reference values from destructive sampling, with a concordance correlation coefficient (CCC) of 0·98. The agreement between AGB estimates from allometric equations and the reference is lower (CCC = 0·68–0·78). Our TLS approach shows a total AGB overestimation of 9·68% compared to an underestimation of 36·57–29·85% for the allometric equations. The error for AGB estimates using allometric equations increases exponentially with increasing DBH, whereas the error for AGB estimates from TLS is not dependent on DBH. The TLS method does not rely on indirect relationships with tree parameters or calibration data and shows better agreement with the reference data compared to estimates from allometric equations. Using 3D data also enables us to look at the height distributions of AGB, and we demonstrate that 80% of the AGB at plot level is located in the lower 60% of the trees for a Eucalypt Open Forest. This method can be applied in many forest types and can assist in the calibration and validation of broad-scale biomass maps.
Satellite based radar interferometry to estimate large-scale soil water depletion from clay shrinkage: possibilities and limitations
Brake, B. te; Hanssen, R.F. ; Ploeg, M.J. van der; Rooij, G.H. de - \ 2013
Vadose Zone Journal 12 (2013)3. - ISSN 1539-1663 - 13 p.
synthetic-aperture radar - sar interferometry - land subsidence - texas vertisols - earths surface - level changes - moisture - volume - insar - field
Satellite-based radar interferometry is a technique capable of measuring small surface elevation changes at large scales and with a high resolution. In vadose zone hydrology, it has been recognized for a long time that surface elevation changes due to swell and shrinkage of clayey soils can serve as an estimate for soil water storage change. Therefore, satellite-based radar interferometry can potentially offer an alternative methodology to estimate soil water storage change at field or regional scales. This paper introduces principles of satellite-based radar interferometry and identifies limitations and potential applications of the technique to measure surface elevation changes from clay shrinkage. In situ measurements were performed and a linear relation between soil water storage depletion and layer shrinkage was obtained. Data from the TerraSAR-X satellite over the measurement area were analyzed to identify the most favorable conditions for radar interferometry to measure vertical shrinkage. High-quality phase observations over clayey areas in polders with limited vegetation can be explained from differences in land use and soil type. Signal noise over sparsely vegetated agricultural fields was successfully reduced by multilooking over agricultural fields at the cost of spatial resolution. Good resemblance between in situ measured shrinkage and differential phase change was found in a test period. Based on this study, we expect that radar interferometric processing of data from the future satellite mission Sentinel-1 can play a crucial role in providing much-needed observations of vadose zone processes at the field scale and beyond.
Hybrid Monte Carlo self-consistent field approach to model a thin layer of a polyelectrolyte gel near an adsorbing surface
Leermakers, F.A.M. ; Bergsma, J. ; Gucht, J. van der - \ 2012
The Journal of Physical Chemistry Part A: Molecules, Spectroscopy, Kinetics, Environment, & General Theory 116 (2012)25. - ISSN 1089-5639 - p. 6574 - 6581.
adsorption - polymers - optimization - interface - volume - ions
The use of thin layers of a surface bound (polyelectrolyte) hydrogels for measuring the concentration of metal ions from electrolyte solutions is our motivation for modeling such hydrogels. The gels are composed of polymeric species with conformational degrees of freedom on the nanometer scale. The polymer conformations are affected by the presence of cross-links in the gel on a five to ten times larger length scale, and the repulsive interactions generated by the charges along the chains. Here we present a hybrid computational Monte Carlo Self-consistent field (MC-SCF) approach to model such hydrogels. The SCF formalism is used to evaluate the conformational properties of the chains, implementing a freely jointed chain model, in between featureless cross-links. The Monte Carlo simulation method is used to sample the (restricted) translational degrees of freedom of the cross-links in the gel. We consider the case that the polymers in the gel have an affinity for surface positioned at the edge of the simulation volume. The polymer density decays as a power-law from the surface to the gel-density with an exponent close to -4/3. The gel features relatively large density fluctuations which is natural for a gel with a low density (f ˜ 0.035), a low degree of cross-linking (average of three chainparts per cross-link), and relatively large chains (N = 50) in between the cross-links. Some parts of the gel can break loose from the gel and sample the adjoining volume. Representative snapshots exemplify large density fluctuations, which explain the large pore size distribution observed in experimental counterparts.
Expected satiation after repeated consumption of low- or high-energy-dense soup
Hogenkamp, P.S. ; Brunstrom, J.M. ; Stafleu, A. ; Mars, M. ; Graaf, C. de - \ 2012
The British journal of nutrition 108 (2012)1. - ISSN 0007-1145 - p. 182 - 190.
food-intake - ice-cream - satiety - humans - palatability - viscosity - volume - fat
We investigated whether repeated consumption of a low-energy-dense (LED; 208 kJ/100 g) or high-energy-dense (HED; 645 kJ/100 g) soup modifies expectations relating to the satiating capacity of the food, and its subsequent intake. In study 1, participants consumed either a novel-flavoured LED (n 32; 21 (SD 1.6) years, BMI 21-4 (SD 1.6) kg/m(2)) or HED soup (n 32; 21 (SD 1-6) years, BMI 21.3 (SD 1.7) kg/m(2)). Soup was served in a fixed amount on days 1-4 and ad libitum on day 5. 'Expected satiation' was measured on days 1, 2 and 5. Expected satiation did not change after repeated consumption of the LED or HED soup. Ad libitum intake did not differ between the LED (461 (SD 213) g) and HED soup (391 (SD 164) g). Only on day 1, expected satiation was higher for the HED soup than for the LED soup (P=0.03), suggesting a role for sensory attributes in expected satiation. In study 2, thirty participants (21 (SD 1-6) years, BMI 21-3 (SD 1.7) kg/m2) performed a single measurement of expected satiation of the LED and HED soup, and four commercially available types of soup. Ratings on sensory attributes were associated with expected satiation. Results on expected satiation coincided with those of study 1. Thickness and intensity of taste were independently associated with expected satiation. Expectations may initially rely on sensory attributes and previous experiences, and are not easily changed.
Research brief : Serving Bowl Selection Biases the Amount of Food Served
Kleef, E. van; Shimizu, M. ; Wansink, B. - \ 2012
Journal of Nutrition Education and Behavior 44 (2012)1. - ISSN 1499-4046 - p. 66 - 70.
portion sizes - college-students - energy-intake - consumption - distortion - illusions - spoons - volume - impact - eaten
Objective: To determine how common serving bowls containing food for multiple persons influence serving behavior and consumption and whether they do so independently of satiation and food evaluation. Methods: In this between-subjects experiment, 68 participants were randomly assigned to either a group serving pasta from a large-sized bowl (6.9-L capacity) or a medium-sized bowl (3.8-L capacity). Results: Analysis of covariance showed that when given a large-sized bowl, diners served 77% more pasta (364.0 versus 205.5 g; P <.01) and felt more satiated (P ¼ .03) compared with diners given a medium-sized bowl, even though the food was not rated tastier or otherwise notable (all P > .32). Conclusions and Implications: In contrast to those in studies involving larger-sized plates and spoons, people serving from larger bowls felt more satiated. These findings again highlight the role that external cues play in food consumption and show the importance of considering serving bowl size in nutrition education.
Scales in single root water uptake models: a review, analysis and synthesis
Metselaar, K. ; Lier, Q.D. van - \ 2011
European Journal of Soil Science 62 (2011)5. - ISSN 1351-0754 - p. 657 - 665.
zea-mays l - soil-water - plant-roots - porous-media - hydraulic conductivity - computed-tomography - system architecture - nutrient-uptake - sample-size - volume
Scales in transport of water to roots are compared with the length and volume scales by using the concepts associated with the representative elementary volume (REV). The possibility of a mismatch between model scale and system scale when using a Darcy-Buckingham-based model to describe soil water transport to a single root is evaluated. In the absence of a mismatch, the replication requirements for evaluating the Darcy-Buckingham-based model near a single root are discussed by using a synthesis of the elementary scales involved, including those for soil, plant and roots, and of the measurement device. By using REV scales from lattice-Boltzmann simulations, the effective half-root mean distance and the available measurement techniques, the evaluation of Darcy-based single root uptake models is possible in roughly 50% of the combinations of soil- and root-system properties. On the basis of an assessment of the scale characterizing natural soil variability, the number of replicates required to assess the average root water uptake profile near a single root is large, and either requires miniaturization of the measurement methods for the hydraulic transport characteristics, or very homogeneous (artificial) growing media with little variability. Variability of water uptake per unit root length will increase the number of samples required.
The effect of operational conditions on the hydrodynamic characteristics of the sludge bed in UASB reactors
Leitao, R.C. ; Santaellla, S.T. ; Haandel, A.C. van; Zeeman, G. ; Lettinga, G. - \ 2011
Water Science and Technology 64 (2011)9. - ISSN 0273-1223 - p. 1935 - 1941.
afvalwaterbehandeling - geactiveerd slib - anaërobe behandeling - slibzuivering - hydrodynamische dispersie - zuiveringsinstallaties - expansie - retentie - volume - waste water treatment - activated sludge - anaerobic treatment - sludge treatment - hydrodynamic dispersion - purification plants - expansion - retention - volume - settling characteristics - expansion characteristics - granular sludge - volume index - velocity - sewage - settleability - design
This work aims to evaluate the hydrodynamic properties of the sludge bed of Upflow Anaerobic Sludge Blanket (UASB) reactors based on its settleability and expansion characteristics. The methodologies used for the evaluation of the settleability of aerobic activated sludge, and for the expansibility of a sludge bed of Expanded Granular Sludge Bed reactors and Fluidised Bed Reactors were adapted and applied to the particular characteristics of the sludge of UASB reactors. An easy-to-build experimental set-up was developed to assess the parameters necessary for the equations of settleability and of expansibility. The results obtained from the sludges of seven differently operated reactors show that, for the treatment of low strength wastewater, settleability increased and expansibility decreased at decreased hydraulic retention time, from 6 to 1 h, and/or increased influent concentrations, from 136 to approximately 800 mg chemical oxygen demand/L. The results also show that it is useless to design an UASB reactor with a longer hydraulic retention time to cope with hydraulic shock loads, as a more expansible sludge will develop at such condition.
Chrysantenteelt op substraatbedden - Kennis over het wortelmilieu
Vermeulen, T. - \ 2011
bloementeelt - substraten - wortels - chrysanten - volume - irrigatie - landbouwkundig onderzoek - floriculture - substrates - roots - chrysanthemums - volume - irrigation - agricultural research
Informatieposter over chrysantenteelt op substraatbedden
Resultaten voorjaarsbloeiers 2010
Vreeburg, P.J.M. ; Kool, S.A.M. de - \ 2011
teeltsystemen - bloembollen - substraten - cultuur zonder grond - volume - water - cropping systems - ornamental bulbs - substrates - soilless culture - volume - water
Informatieposter over teeltdegronduit, resultaten voorjaarsbloeiers 2010. Doel van het op de poster gepresenteerde onderzoek was het verkennen van de mogelijkheden van bollenteelt los van de grond in klein volume, diverse substraten en waterteelt
The effects of food viscosity on bite size, bite effort and food intake
Wijk, R.A. de; Zijlstra, N. ; Mars, M. ; Graaf, C. de; Prinz, J.F. - \ 2008
Physiology and Behavior 95 (2008)3. - ISSN 0031-9384 - p. 527 - 532.
physical state - body-weight - satiety - volume - beverages - humans
Two studies investigated the effect of a food's viscosity on bite size, bite effort and food intake using a standardized protocol in which subjects sipped through a straw every 20 s for a period of 15 min from one of two products, a chocolate-flavored dairy drink and a chocolate-flavored dairy semi-solid, matched for energy density. In the first study, subjects consumed 47% more from the liquid than from the semi-solid to reach the same degree of satiation, with larger bite sizes for the liquid throughout the 15 minute period (8.7 ± 0.45 g) compared to the semi-solid (5.8 ± 0.3 g, p <0.01). In the second study bite effort was eliminated by using a peristaltic pump to present the products every 20 s. Oral processing time before swallowing was set at 5 s (both products) or 8 s (semi-solid). With the elimination of bite effort and a standardized oral processing time, subjects consumed as much from the semi-solid as from the liquid to reach the same degree of satiation. Bite size for liquids started relatively small and grew gradually over successive bites, whereas the bite size for the semi-solid food started relatively large and became gradually smaller. The latter effect was even more pronounced when the oral processing time was increased from 5 to 8 s. In conclusion, semi-solids resulted in smaller bite sizes and lower intake than liquids, but these differences disappeared when differences in bite effort were eliminated.
Maximum tumor diameter is not an independent prognostic factor in high-risk localized prostate cancer
Oort, I.M. van; Witjes, J.A. ; Kok, D.E.G. ; Kiemeney, L.A. ; Hulsbergen-van de Kaa, C.A. - \ 2008
World Journal of Urology 26 (2008)3. - ISSN 0724-4983 - p. 237 - 241.
radical prostatectomy - multivariate-analysis - antigen recurrence - specimens - predictor - volume - carcinoma - failure - progression - men
Previous studies suggest that maximum tumor diameter (MTD) is a predictor of recurrence in prostate cancer (PC). This study investigates the prognostic value of MTD for biochemical recurrence (BCR) in patients with PC, after radical prostatectomy (RP), with emphasis on high-risk localized prostate cancer. Methods RP specimens of 542 patients were evaluated with a median follow-up of 39.5 months (range 0.6¿150 months). MTD was defined as the largest diameter of the largest tumor; high-risk as ¿T2c or PSA level > 20 ng/ml or Gleason score ¿8 and BCR as two consecutive PSA levels > 0.10 ng/ml. Proportional hazards multivariable regression models were composed to determine prognostic factors for BCR. Results Overall, 114 patients developed BCR after RP. The overall 5-year risk of BCR was 25% (95% CI = 20.4¿29.6), and median MTD was 24 mm (range 1¿65). MTD in the total and high-risk group was associated with total tumor volume, volume of the largest tumor, pre-operative PSA levels, and Gleason score. In a univariable analyses, MTD was weakly associated with risk of BCR (HR = 1.02 per mm increase, 95% CI = 1.002¿1.035, P = 0.024) in the total group; in the high-risk group this association was lost (HR = 1.01, 95%CI = 0.99¿1.03, P = 0.18). Multivariable analyses indicated that positive surgical margins, higher Gleason score, advanced pathological stage, and multiple tumors were the main prognostic factors for BCR irrespective of the risk profile. MTD did not provide additional information. Conclusions MTD is not an independent prognostic factor for BCR in patients treated with RP, irrespective of the risk profile
Modelling soil anaerobiosis from water retention characteristics and soil respiration
Schurgers, G. ; Dörsch, P. ; Bakken, L. ; Leffelaar, P.A. ; Egil Haugen, L. - \ 2006
Soil Biology and Biochemistry 38 (2006)9. - ISSN 0038-0717 - p. 2637 - 2644.
denitrification - emissions - volume - n2o
Oxygen is a prerequisite for some and an inhibitor to other microbial functions in soils, hence the temporal and spatial distribution of oxygen within the soil matrix is crucial in soil biogeochemistry and soil biology. Various attempts have been made to model the anaerobic fraction of the soil volume as a function of structure, moisture content and oxygen consumption. Aggregate models are attractive but difficult to parameterize and not applicable to non-aggregated soils. Pore models are preferable for pragmatic reasons, but the existing versions appear to overestimate the anaerobic volume at intermediate soil moisture contents. A modified pore model is proposed, in which anaerobiosis is calculated from a range of air filled pore size classes, based on the soil water retention curve and the soil moisture content. In comparison with previous pore models which are based on the estimation of an average size of the air filled pores, the pore class model presented here appears to give more adequate estimates of anaerobic volumes, especially at intermediate moisture contents. The pore model is attractive for process modelling of anaerobic functions such as denitrification, since it can easily be parameterized by the water retention characteristics of a soil
Simulation of capillary flow with a dynamic contact angle
Mourik, S. van; Veldman, A. ; Dreyer, M. - \ 2005
Microgravity - Science and Technology 17 (2005)3. - ISSN 0938-0108 - p. 87 - 93.
line - gravity - surface - volume
A number of theoretical and empirical dynamic contact angle (DCA) models have been tested in a numerical simulation of liquid reorientation in microgravity for which experimental validation data are available. It is observed that the DCA can have a large influence on liquid dynamics in microgravity. Correct modelling of the DCA is found to be essential for realistic numerical simulation, and hysteresis effects cannot be ignored
Updating cover type maps using sequential indicator simulation
Magnussen, S. ; Bruin, S. de - \ 2003
Remote Sensing of Environment 87 (2003)2-3. - ISSN 0034-4257 - p. 161 - 170.
land-cover - accuracy assessment - classification - improve - prediction - agreement - imagery - volume - models - issues
Maximum posterior probability (MAP) maps of forest inventory (FI) cover type classes were produced from a maximum likelihood (ML) classified TM image and 5% (2%) systematic reference sampling of actual cover types for of nine 2 x 2 kin study sites in New Brunswick, Canada. MAP cover type maps were obtained via sequential indicator simulation (SIS) using collocated indicator cokriging. A 5% reference sampling increased the coefficient of accuracy of MAP cover type maps by about 0.2 compared to the accuracy of the ML classified maps. MAP prediction errors were obtained for global and small area estimates of cover type extent. MAP-based cover type statistics of extent and precision were compatible with corresponding results for maximum likelihood bias-corrected estimates (MLE). Spatial autocorrelation of MAP prediction errors declined rapidly with distance and were near 0 for distances of more than 3-4 Landsat TM pixels. MAP cover type maps produced by SIS are attractive when both global and local estimates of precision of map-derived statistics are needed. (C) 2003 Published by Elsevier Inc.
A comparison of the effects of added saliva, alpha-amylase and water on texture perception in semisolids
Engelen, L. ; Wijk, R.A. de; Prinz, J.F. ; Janssen, A.M. ; Bilt, A. van der; Weenen, H. - \ 2003
Physiology and Behavior 78 (2003)4-5. - ISSN 0031-9384 - p. 805 - 811.
custard desserts - flow-rate - secretion - flavor - volume - taste - ph
The effect of adding saliva or a saliva-related fluid (-amylase solution and water) to custard prior to ingestion on the sensory ratings of odour, flavour and lip¿tooth-, mouth- and after-feel sensations was investigated. Saliva had previously been collected from the subjects and each subject received his/her own saliva. Sixteen subjects from a trained panel assessed 17 flavour and texture attributes of soy- and milk-based custard desserts. Immediately prior to administration, two different volumes (0.25 and 0.5 ml) of three different saliva-related fluids (saliva, -amylase solution and water) were added to the product. The added volumes represented an approximately 33 nd 66 ncrease of the volume of saliva present in the mouth during ingestion. The results show that addition of a fluid affected the mouth-feel attributes of melting, thickness and creamy. Melting was the only attribute on which the type of fluid had an effect, where saliva elicited a stronger melting effect than the -amylase solution and water. The volume of the added fluid affected a number of attributes (thick and creamy mouth-feel and fatty after-feel). It can be concluded that in general the sensory attributes of semisolids were relatively stable. Mouth- and after-feel sensations were partly affected, while odour, flavour and lip¿tooth-feel sensations were not affected by an increase in volume of saliva or other saliva-related fluid during ingestion.
When are stockpiled products consumed faster? A convenience-salience framework of postpurchase consumption incidence and quantity
Chandon, P. ; Wansink, B. - \ 2002
Journal of Marketing Research 39 (2002)3. - ISSN 0022-2437 - p. 321 - 335.
price promotions - variety-seeking - self-control - usage - choice - sales - behavior - memory - recall - volume
When people stockpile products, how do they decide when and how much they will consume? To answer this question, the authors develop a framework that shows how the salience and convenience of products influence postpurchase consumption incidence and quantity. Multiple research methods¿including scanner data analysis, a field study, and two laboratory studies¿show that stockpiling increases product salience and triggers consumption incidence among high-convenience products. However, when the decision is made to consume a product, stockpiling increases the consumption quantity for both high- and low-convenience products. In addition to providing new insights on how consumers make postpurchase consumption decisions, these results have implications for the debate on the value of promotions that induce stockpiling.
Nauwelijks compostering vaste mest op het lagekostenbedrijf
Blanken, K. ; Dooren, H.J. van - \ 2001
Rundvee praktijkonderzoek 14 (2001)3. - ISSN 1569-805X - p. 5 - 7.
stalmest - rundveemest - mest - opslag - compostering - samenstelling - chemische samenstelling - volume - massa - gewicht - mestverwerking - farmyard manure - cattle manure - manures - storage - composting - composition - chemical composition - volume - mass - weight - manure treatment
Gedurende een half jaar werd daarom de opslag van de vaste mest in een proefopstelling gevolgd. Hieruit bleek dat er vrijwel geen compostering op gang kwam en dat de massareductie daardoor minder is dan verwacht.
De psychologie van de houtmeter en zijn gelijk
Schulting, R. - \ 2000
Nederlands Bosbouwtijdschrift 72 (2000)3. - ISSN 0028-2057 - p. 90 - 94.
houtmeetkunde - bosbouw - bosinventarisaties - bomen - monsters - volume - volumebepaling - tapsheid - stamvorm - stamhout - meting - richtlijnen (guidelines) - handel - marketing - economie - bosbouweconomie - bosopstanden - mensuration - forestry - forest inventories - trees - samples - volume - volume determination - taper - stem form - logs - measurement - guidelines - trade - marketing - economics - forest economics - forest stands
Meting van liggend en staand rondhout. Een evaluatie van de bestaande richtlijnen, en welke bewuste of onbewuste fouten er in de praktijk worden gemaakt bij het bepalen van het houtvolume. De gebruikte gegevens zijn afkomstig van de houtmeetcursussen georganiseerd door Praktijkschool Arnhem (nu IPC)
De kroon op het regenbos.
Bongers, F. - \ 1997
Nederlands Bosbouwtijdschrift 69 (1997)3. - ISSN 0028-2057 - p. 98 - 103.
bosbouw - afmetingen - volume - kroon - kroondak - meting - experimenten - statistiek - simulatie - nederland - forestry - dimensions - volume - crown - canopy - measurement - experiments - statistics - simulation - netherlands
Onderzoek aan het kronendak: bereikbaarheid, klimaat, planten en dieren