Het klimaat en de verdamping van een meer in Centraal Irak

After describing the continental subtropical climate of central Iraq, Wartena assembled other meteorological observations necessary to estimate evaporation from a lake and irrigation project.Usual formulae correlating total global radiation with duration of sunshine gave an overestimate with clear sky, an underestimate with cloud cover. A new relationship was derived which gave better results.A critical discussion of the energy balance of an evaporation pan clearly showed that 'pan factors' could not be constants but depended on weather conditions and time of year. Kohler's theory yielded inaccurate results. Especially in and regions, to assume a constant ratio between 'potential' and actual evaporation may lead to considerable error but a 'class A' pan satisfactorily indicated irrigation requirements. The 'Piche' evaporimeter was not satisfactory.To estimate evaporation from the projected storage lake, its surface temperatures were calculated by using elementary meteorological quantities. The method was in reasonable agreement with actual values on the existing Lake of Tiberias. The evaporation from fictitious lakes 10 and 50 metres deep was calculated to be different.Qualitative influences of wind, humidity and temperature of the atmosphere on evaporation were discussed.Yearly evaporation from the two lakes was estimated at 2500 mm.<p/

De invloed van het weer op de toepassing van gewasbeschermingsmiddelen.

Het weer heeft grote invloed op het succes van de werking van de gebruikte gewasbeschermingsmiddelen. In het verslag worden enkele belangrijke weersparameters besproken zoals temperatuur en relatieve luchtvochtigheid (RV) die van belang zijn voor de werking van de middelen. Ook de interactie tussen de plant en de weersparameters wordt behandeld. De opname van middelen in de plant wordt beïnvloed door de cuticula en de waslaag en de vochtigheid na toepassing van het middel. Ook de wijze waarop de middelen geformuleerd zijn beïnvloedt de hechting en opname en dus de werking van de middelen. De Phytophthoramiddelen behoren tot de fungiciden. Van de fungiciden wordt algemeen gesteld dat de contactfungiciden voor een goede hechting na toepassing droog, zonnig weer nodig hebben, zodat het middel snel op het blad kan vastdrogen. Regen na toepassing bekort de werkingsduur, buien met een hoge intensiteit hebben meer invloed dan regenperioden met een lage intensiteit. Bij systemische fungiciden is neerslag, na opname, minder erg. Temperatuur en RV zijn belangrijker voor de werking van systemische middelen. Een temperatuur tussen 15-22 C en een RV groter dan 80% zorgt voor een snel resultaat. In de bijlagen van het rapport worden per fungicide de invloed van weerparameters op de werkzaamheid beschreven. Sleutelwoorden: PPO-agv, akkerbouw, gewasbescherming, geïntegreerde bestrijding, aardappelen, phytophthora, vollegrondsgroententeelt, geintegreerde teelt, phytophthor

Clustering cliques for graph-based summarization of the biomedical research literature

BACKGROUND: Graph-based notions are increasingly used in biomedical data mining and knowledge discovery tasks. In this paper, we present a clique-clustering method to automatically summarize graphs of semantic predications produced from PubMed citations (titles and abstracts). RESULTS: SemRep is used to extract semantic predications from the citations returned by a PubMed search. Cliques were identified from frequently occurring predications with highly connected arguments filtered by degree centrality. Themes contained in the summary were identified with a hierarchical clustering algorithm based on common arguments shared among cliques. The validity of the clusters in the summaries produced was compared to the Silhouette-generated baseline for cohesion, separation and overall validity. The theme labels were also compared to a reference standard produced with major MeSH headings. CONCLUSIONS: For 11 topics in the testing data set, the overall validity of clusters from the system summary was 10% better than the baseline (43% versus 33%). While compared to the reference standard from MeSH headings, the results for recall, precision and F-score were 0.64, 0.65, and 0.65 respectively

Het klimaat en de verdamping van een meer in Centraal Irak

After describing the continental subtropical climate of central Iraq, Wartena assembled other meteorological observations necessary to estimate evaporation from a lake and irrigation project.Usual formulae correlating total global radiation with duration of sunshine gave an overestimate with clear sky, an underestimate with cloud cover. A new relationship was derived which gave better results.A critical discussion of the energy balance of an evaporation pan clearly showed that 'pan factors' could not be constants but depended on weather conditions and time of year. Kohler's theory yielded inaccurate results. Especially in and regions, to assume a constant ratio between 'potential' and actual evaporation may lead to considerable error but a 'class A' pan satisfactorily indicated irrigation requirements. The 'Piche' evaporimeter was not satisfactory.To estimate evaporation from the projected storage lake, its surface temperatures were calculated by using elementary meteorological quantities. The method was in reasonable agreement with actual values on the existing Lake of Tiberias. The evaporation from fictitious lakes 10 and 50 metres deep was calculated to be different.Qualitative influences of wind, humidity and temperature of the atmosphere on evaporation were discussed.Yearly evaporation from the two lakes was estimated at 2500 mm