bluuebunny/crossref_metadata_2025_split huggingface dataset:
Systems Analysis and Dynamic Simulation1)
Authors: WIT C.T. DE , RABBINGE R. 
Published: April 2008

AbstractThe state–variable approach to systems analysis and dynamic simulation is based on the assumption that the state of each system at any moment may be quantitatively characterized and that changes in state may be described by mathematical equations.The basic distinction between state, rate and driving variables in this approach is illustrated by examplesThe conflict resulting from the large number of state variables that may be distinguished in any ecological system and the small number that can be handled in simulation models is treated and attention is given to the distinction between unique and recurring systems, especially with reference to the problem of model evaluation.
Digital Simulation Languages: Problems and Possibilities1)
Authors: ELZAS M.S. 
Published: April 2008

AbstractWhen faced with a model to be simulated on a computer, one is in general faced with a series of problems, to which answers are quite often difficult to find. These problems include:1) Can we construct a mathematical approximation of the model in such a way that the resulting formulation can be implemented as a computer for simulation purposes ? 2) Will the above mathematical formulation guarantee a result on an ideal (perfect) machine ? 3) Will the chosen method of simulation withstand the non–ideal characteristics of an actual machine ? 4) Will it be possible to compute results to the computing sequence that is created for the simulation ? 5) How does one choose the right language that is to be the programming vehicle for the simulation ? 6) Can one describe every simulation problem in any of the languages for specific classes of problems ?This paper tries to give an insight into the possible answers to these questions and endeavours to provide the reader with some basic knowledge about the possibilities available and the problems to look for when setting up simulation experiments by programming them with simulation languages for digital computers.
CROPS: a GASP IV Based Crop Simulation Language1)
Authors: MILES G.E. , PEART R.M. , HOLT D.A. , PRITSKER A.A.B. , BULA R.J. 
Published: April 2008

AbstractCROPS is a GASP IV based simulation language which emphasizes the development of the equations which model crop physiology. The CROPS philosophy of physiology is to first divide the crop into constituents (carbon, nitrogen, phosphorus, potassium and water) and then partition the crop into compartments (leaves, grain, stems, and roots). Flows of constituents between compartments are illustrated by system dynamics diagrams. A crop model consists of the equations which describe these constituent flows and which are totally user–specified in separate FORTRAN functions.The CROPS coding (which is a specially written set of GASP IV user routines) accomplishes all other tasks normally required in a crop simulation. CROPS automatically processes weather data, collects and reports statistics on crop growth rates and relative growth rates, and prints status reports on simulated crop conditions. In addition, all GASP IV support routines (plots, histograms, etc.) are available to the CROPS user. A reference manual, which provides complete documentation, and a mini–tutorial, which introduces the reader to using CROPS, are also available.
Variation du microclimat d'une culture en fonction de ses caractéristiques biologiques1
Authors: PERRIER A. 
Published: April 2008

SommaireOn utilisera pour souligner aussi bien le rôle des facteurs climatiques dominant que celui des caractéristiques biologiques de la plante, structure ou régulation stomatique, un modèle analytique du couvert, basé sur les équations de transfert. Ce modele permet d'illustrer, de préciser et de quantifier la variation des principaux paramètres que sont la vitesse du vent, la température et l'humidité tant au sein du couvert qu'au–dessus. Le röle particulier de la pluie et des irrigations sur le microclimat sera mis en évidence, ainsi que le röle de la densité de population et de la hauteur du couvert considéré.Enfin, on soulignera, compte tenu de la répartition verticale du feuillage, comment ces variations microclimatiques peuvent être trés diversifiés selon la hauteur considérée au sein du couvert.
Bond Graphs and Minicomputers in Greenhouse Climate Control1)
Authors: BOT G.P.A. , DIXHOORN J J. VAN 
Published: April 2008

AbstractThis paper is concerned with the modelling and simulation method used in greenhouse climate control. A bond graph is a topological diagram, clearly representing any kind of physical network. In this case, the bond graph models the heat and vapour flows between compartmented components and the coupling between heat and vapour flow.The bond graph can easily be converted into a differential equation model to be solved, for example, by CSMP. In the present case, however, the bond graph was used as a direct input to an interactive simulation program on a minicomputer. The method was applied to model an experimental greenhouse described by STANHILL et al. 1973.
Simulation of Epidemics: Problems and Applications1
Authors: ZADOKS J.C. 
Published: April 2008

AbstractA review is given of some disease simulation models. There have been 2 schools of thought in simulating disease progress with time. Three further models have simulated disease progress in time and space. The accuracy of the models depends, in part, on the time span (in generations or in days) covered and the overall multiplication over that time span. In these respects, models differ considerably. Spatial models can be used to study the epidemiological effect of multiline varieties and mosaic patterns of varieties. Disease simulation models can be used for guidance in research, disease forecasting, plant breeding strategies, supervised and integrated control, but much further development, including sensitivity testing, is needed.
Simulation of Epidemics Caused by Venturia inaequalis (Cooke) Aderh.1
Authors: KRANZ J. 
Published: April 2008

AbstractWe discuss simulation of apple scab epidemics based on analog computer models, multivariate regression analyses, and systems analyses. Details of underlying models and their scope for applications are emphasized. Monomolecular growth functions by Bertalanffy and Gompertz in analog computers permit fast simulation of disease progress curves. The models derived from multivariate analyses of field experiments on apple scab epidemics simulate closely the changes in infection rates. EPIVEN, our comprehensive and self–generating simulator of apple scab epidemics is reviewed and compared to a reduced model, also based on elements of the system “apple scab epidemic”.
Modélisation de transports horizontaux (spores, pollen)1)
Authors: ITIER B. , PAUVERT P. 
Published: April 2008

SommaireA partir d'un mod&le analytique de diffusion, nous calculons l'evolution horizontale et verticale des concentrations et des flux d'aerosols emis par une sur‐face ou un couvert vegetal. Ce modele s'applique i deux cas particuliers:‐ soit concentration constante au‐dessus de la zone d'emission,‐ soit flux d'hission constant sur toute la zone.Les flux de concentration en aerosols sont calcules tout d'abord sur la zone d'kmission et i l'inttrieur de sa propre couche limite de diffusion. Dans un deuxikme temps, on s'interesse i ces mCmes quantites au‐deli de la zone d'tmis‐ sion de maniere i calculer les retombees.Pour une mCme concentration sur la zone d'emission et une mCme rugositt de surface, ces retombees dependent de quatre paramPtres: la vitesse du vent, la vitesse de sedimentation des aerosols, la dimension de la zone d'emission et la distance i cette zone.Reference est faite i un exemple d'application concernant quelques maladies i dissemination anemophile telles que l'oldium de l'orge et la rouille du bli et nous discutons ducomportement des particules en fonction de valeurs <(seuil)> de la vitesse du vent.
A Data Bank on Crop Losses: First Experiences1)
Authors: RIJSDIJK F.H. , ZADOKS J.C. 
Published: April 2008

AbstractThe third of a series of Agro–ecological Atlases on Cereal Growing in Europe, published under the auspices of the European Cereal Atlas Foundation, will deal with pests and diseases of cereals. Information was collected and stored in a data bank before processing. Data processing leads to two kinds of outputs:1. Loss maps of Europe show the mean annual loss due to each cereal pest and disease by means of isoloss curves;2. Risk maps of Europe for selected pests and diseases show the relative risk incurred by the cereal crop in each climatic area as determined by the climate of that area, areas with equal risk being separated by isorisk curves.
Optimal Integrated Control of Alfalfa Weevil, Hypera postica (Gyllenhal) (Coleoptera: Curculionidae)1)
Authors: SHOEMAKER Christine A. 
Published: April 2008

AbstractThe use of optimization methods to determine single and multidimensional economic thresholds for insect pests in discussed. A review of previous applications of optimization methods to pest management problems is followed || by a detailed description of an application to alfalfa weevil management. This model uses dynamic programming to determine the best combination of chemical, cultural and biological means for control of the alfalfa– weevil. The model includes stochastically varying weather patterns, seven weevil age–classes, three parasite age–classes, and five alfalfa plant components. The decision variables include times of harvest and insecticide applications over a three–year period. The multi–dimensional economic thresholds calculated depend upon parasite density and weather, as well as upon alfalfa–weevil density. Results for central New York, USA, are presented.
Problems of Estimating the Need for and Timing of Control Measures Against Pests and Diseases of Crops1
Authors: HULL R. , DUNNING R.A. 
Published: April 2008

The problems are as numerous and diverse as the biology of the various organisms causing damage to crops. They are compounded by the differences in reaction of crops cultivated in different ways, by weather sequences over long periods or short periods and the interactions of all three factors;noxious organisms, crops and weather.To ensure that control measures are economically justified, their need must be assessed on the basis of probable crop loss if no precautions are taken. The relationship between the intensity and timing of the infestation of the crop by the noxious organisms, crop damage and crop loss must be determined. In some instances, this is straight forward;in others, very complicated.The assessment of the probability of infestation may be based on existing population levels, on intervening weather, on crop examination for the start of infestation, on the occurrence of critical environmental conditions, or on the transport of inoculum. Having developed a warning system, how is the information conveyed to the grower? Warning systems are based on past experience, but how stable are they ? Pathogens change, crop cultivation practices change, available controls change. The problems of estimating the need for and timing or control measures are likely to be continuing ones for the biologist and crop specialist.Les problèmes sont aussi nombreux et diversifyés que la biologie des organismes nuisibles eux‐mêmes. Les réactions dissemblables des cultures soumises à différents modes de culture, les séquences méteorologiques à court et a long terme ainsi que les interactions entre L'organisme nuisible, la culture et le temps sont autant d'élements qui ajoutent à la complexite des phénomenes.La justification économique dune méthode de lutte repose sur I'évaluation de la perte de récolte a laquelle il faut s'attendre en I'absence de protection. Cette évaluation, plus ou moins diffcile, tiendra compte de I'importance et de la durée de la contamination en fonction du dommage que subit la culture et des pertes de récoltes qui en résultent.L'évaluation de la probabilityé d'une infestation peut reposer sur la densité de la population au moment du contrble, les conditions météorologiques prévalentes, la detection d'une attaque primaire de la culture, L'apparition de conditions critiques dans une biocoenose, ou la possibilityé de dissemination de L'inoculum. Lorsqu'un système d'avertissement a éte développé, la question est de savoir de quelle faGon L'information peut atteindre le cultivateur. Les systemés d'avertissement sont basés sur des expériences acquises, mais quelle est leur fiabilite ? L'organisme change de méme que les modes de culture et de lutte. I1 s'ensuit que I'evaluation de la necessite et du moment de I'intervention phytosanitaire doit être continuellement reconsideré par le biologiste et I'agronome.
Forecasting and Warning in Danish Agriculture1
Authors: WAGN O. 
Published: April 2008

In Denmark, the principle is maintained of forecasting and warning against pests and diseases which are not easily recognized by the farmer himself. The forecasting and warning system is based upon close cooperation between the farmers' unions, a well‐organized network of plant husbandry advisers and the State Plant Pathology Institute in Lyngby. Most field data are collected by the advisers and forwarded to Lyngby from where announcements on current attacks are distributed as appropriate. Realizing the considerable local variations in the occurrence and course of the attacks, plant pathologists mainly notify the advisers, who can then intervene, if necessary, with a local warning for their own districts. Potato blight, however, is an exception, country‐wide forecasting being broadcast every year. This may also be the case with warnings againts aphids. Potato blight forecasting has been in operation since 1935 and warnings against aphids in beets (causing virus yellows) since 1957. Each year about 10 different pests and diseases are warned against.Au Danemark, le principe prévaut d'assurer les prévisions et les avertissements pour les déprédateurs qui ne sont pas facilement dépistés par I'exploitant. Le système se base sur une coopération étroite entre les syndicats dexploitants, un réseau bien organisé de conseillers agricoles, et 1'Institut national de phytopathologie à Lyngby. Les observations de plein champ sont realisees par les conseillers qui transmettent les resultats a Lyngby. L'Institut assure alors la dissemination des informations sur les attaques en cours. Compte tenu de la forte variation regionale de L'incidence et de I'evolution des attaques, les phytopathologues avertissent les conseillers qui decident s'il y a lieu d'emettre des avertissements dans leur district. Le mildiou de la pomme de terre, cependant, est considere au niveau national et, suivant les cas, egalement les pucerons. Les previsions contre le mildiou sont en place depuis 1935, et contre les pucerons de la betterave (vecteur du yellows virus) depuis 1957. Chaque années, une dizaine de ravageurs et maladies font L'objet d'avertissements.
Possibilités de prévisions écoclimatiques par L'interprétation d'images‐satellite en infrarouge1
Authors: MUELLER W. 
Published: April 2008

La photographie aérienne « classique » ou par satellites, en infrarouge (IR) surtout, offre des possibilités nouvelles en matière de prévision écoclimatique à moyenne et à grande échelle. Ces données peuvent être intégrées dans un modèle prévisionnel reproduisant la dynamique des populations des ravageurs et des parasites. L'utilisation de L'IR, dit véritable, permet d'établir une cartographie thermique des surfaces et, dans certains cas, d'enregistrer les courant d'air à proximité du sol. Dans le cas du satellite ERTS 1, L'utilisation de simples filtres (MSS 5 et 7) permet de cartographier les plans d'eau et, par superposition chronologique de photos, il est également possible de tirer quelques conclusions quantitatives sur le bilan hydrique, la variation de L'humidité du sol et L'état de la végétation qui font partie intégrante de la prévision.Aerial photographs, whether obtained by classical or satellite methods, offer new possibilities for ecoclimatological forecasting on a medium or large scale. This is particularly the case for infra‐red photography. This forecasting can readily be integrated into larger scale models for parasite population dynamics. The use of true infra‐red photography allows thermic mapping of the ground, and, under certain conditions, mapping of air currents near the ground. Simple filters (MSS 5 and 7 for the ERTS 1 satellite) make it possible to map water surfaces, and, by superposition, to come to conclusions on water balance, variations in soil moisture, and the state of vegetation ‐ all useful in forecasting.
Agrometeorological Conditions Determining the Occurrence of Potato Blight (Phytophthora infestans de Bary) in Poland1
Authors: UTRATA A. 
Published: April 2008

Using phytopathological and climatological data covering the period 196 1 ‐ 1965, the author considers the problem of the influence of chosen meteorological factors during June‐September on the intensity of potato blight. Multiple regression equations are given for average conditions and for selected soil groups comprising either districts with adequate water conditions or those with a predominance of soils that are usually too dry. The influence of soil type on the hazard index of potato blight is shown. By using the mean values of the meteorological factors for the period 1930‐ 1961 in the equations, hazard index maps of potato blight distribution in Poland are plotted. The equations, together with the data on the empirical probability that the disease may occur (resulting from the meteorological conditions), can also be used for forecasting the disease intensity in a given year.L'auteur a étudié les effects du climat sur le mildiou de la pomme de terre en cherchant à dégager la relation entre certains paramétres météorologiques et l'épidémiologie de la maladie. Ces études ont été entreprises de juin à septembre durant la période s'étendant de 1961 à 1965. Une régression multiple a pu être établie pour des conditions moyennes et pour certains types de sol, dans des régions à conditions hydrologiques differentes. Il est démontré que le risque de mildiou est influenceé par le type de sol et que, par référence à la période 1930–1961, les valeurs moyennes des facteurs météorologiques peuvent être utilisées pour établir des cartes indiquant le risque de mildiou en Pologne. Les équations de régression, ainsi que les donneés sur la probabilityé de L'apparition de la maladie, en fonction de conditions météorologiques données, peuvent être utilisees pour prédire Ie niveau d''attaque pendant L'année considérée.
Some Problems in Using Meteorological Data to Forecast the Timing of Insect Life Cycles1
Authors: BAKER C.R.B. 
Published: April 2008

Sources of error in using accumulated temperatures for estimating the timing of events in insect life cycles, such as adult emergence and egg hatching, have rarely been examined in detail. There are two sources of error, one in the calculations, the other in the observations. Errors in the calculations arise from using the wrong base temperature, from using the daily arithmetic mean temperature in the calculation of the daily effective temperature on occasions when the mean is not appropriate and, occasionally, in using the linear relationship between temperature and growth where a non‐linear relationship would be more appropriate. Errors in observations arise mainly from attempts to employ standard meteorological measurements rather than measurements made from sites where the insects normally live. Temperature measurements in the soil at different depths on the flat and on north and south slopes, on the bark of trees and on the leaves of plants have been converted into estimates of insect development to demonstrate the effect of local differences in microclimate. It is strongly emphasized that day‐degrees as units of effective temperature in temperature summation calculations are physiological units of growth and not physical units of heat energy input.Les sources d'erreurs résultant de L'utilisation de la somme des températures pour prévoir le déroulement des cycles évolutifs des insectes (éclosion des adultes, ceufs, etc.) n'ont guère étéétudiées de rnanière approfondie. De L'avis de L'auteur, ces erreurs peuvent provenir de I'observation et du calcul. En ce qui concerne ce dernier, L'utilisation dune fausse température de base, résultant du recours à une moyenne arithmétique de la température quotidienne établie à tort, est préjudiciable. D'autre part, le résultat peut être faussé lorsqu'il est recouru à une relation linéaire entre la temperature et la croissance alors qu'il serait préferable de tenir compte d'une relation non linéaire.Les erreurs d'observation concernent principalement L'utilisation de données météorologiques à caracère général, au lieu de se référer à celles qui prévalent au site même où se trouve L'insecte. La détermination de la temperature du sol à des profondeurs différentes, sur terrain plat ou incline vers le nord ou le sud, ainsi que de la température de l'écorce des arbres ou des feuilles des plantes rvele L'influence du microclimat sur le développement des insectes. Il est souligné que le degre‐jour, utilisé dans les calculs de sommes de témperatures, est une unite physiologique de croissance et non une unité physique dabsorption d'énergie thermique.
Standardization of Pest Assessment1
Authors: WALKER P.T. 
Published: April 2008

The first need in forecasting, in decision making in pest management on an economic base, for research and in breeding for resistance, is a good method of pest or disease assessment. This should be standardized, quantitative, repeatable, quick and simple, and give details of the signs of attack and effect on the crop.Examples of this approach from drafted or published FAO Crop Loss Assessment Methods are given, one for assessment of nymphs and bugs of the Sunn pest complex on cereals, one on Dacus fly on olives, and one on Aonidiella scale on citrus leaves.The need for continued international cooperation in developing, publishing and testing assessment methods is stressed.Une méthode fiable d'avaluation de L'incidence des ravageurs et des maladies constitue l'élément fondamental sur lequel doivent pouvoir s'appuyer les prévisions, la sélection de cultivars résistants et toute autre décision prise dans le cadre dun système de lutte integrée. Les techniques normalisées, simples et rapides, mises en ceuvre pour apprécier la signification des déprédateurs, devraient également faire état de la symptomatologie et de L'effet que ceux‐ci exercent sur la culture. L'auteur cite des exemples de méthodes d'valuation des pertes de récoltes publicées par I'OAA ou en voie d'étude en se référant plus particulièrement au dénombrement des nymphes et des adultes de differentes espèces d'Eurygaster et Aelia sur céréales, et a ceiui de Dacus oleue sur olivier et d'anonidiella aurantii sur feuilles d'agrumes. Le developpement, la publication et l'évaluation des méthodes exigent une cooperation internationale suivie.