Applications of Artificial Neural Networks in integrated water management: fiction or future?

An Artificial Neural Network (ANN) is nowadays recognized as a very promising tool for relating input data to output data. It is said that the possibilities of artificial neural networks are unlimited. Here we focus on the potential role of neural networks in integrated water management. An Artificial Neural Network (ANN) is a mathematical methodology which describes relations between cause (input data) and effects (output data) irrespective of the process laying behind and without the need for making assumptions considering the nature of the relations. The applications are widespread and vary from optimization of measuring networks, operational water management, prediction of drinking water consumption, on-line steering of wastewater treatment plants and sewage systems, up to more specific applications such as establishing a relationship between the observed erosion of groyne field sediments and the characteristics of passing vessels on the river Rhine. Especially where processes are complex, neural networks can open new possibilities for understanding and modelling these kinds of complex processes. Besides explaining the method of ANN this paper shows different applications. Three examples have been worked out in more detail. An intelligent monitoring system is shown for the on-line prediction of water consumption, ANN are successfully used for sludge cost monitoring and optimizing wastewater treatment and the usage of ANN is shown in optimizing and monitoring water quality measuring networks. An ANN appears to be a multiuse and powerful tool for modelling complex processes.

[A repeat advice no longer applies for cervical smears without endocervical cells in population studies for cervical cancer]. / Geen herhalingsadvies meer bij een cervixuitstrijk zonder endocervicale cellen in het bevolkingsonderzoek op baarmoederhalskanker.

Recent Dutch and non-Dutch studies have shown that the absence of endocervical cells (ecc-) in an adequate cervical smear does not present an increased risk for the presence or occurrence of cervical cancer or premalignant abnormalities in a later phase. Based on these findings, the Coordination Committee Cervical Cancer Screening of the Dutch Health Insurance Council had advised dropping the repeat advice for non-abnormal ecc- smears by January 1st 2002. The National Health Insurance Council has agreed to this advice. The following measures have been taken: (a) no repeat advice for ecc- smears; in the case of negative findings the woman waits until the next five-yearly invitation from the screening programme; (b) whether the portio cervicis was seen has to be stated on the national request form; (c) the reporting of an ecc- in the cytology report and periodical feedback to general practitioners remains unchanged; (d) in the case of a non-abnormal ecc- smear with an uninspected portio or doubts as to whether the transformation zone was adequately scraped, either the smear will have to be repeated or the patient will have to be referred to the gynaecologist.

The Role of Ethylene in Interorgan Signaling during Flower Senescence.

The roles of 1-aminocyclopropane-1-carboxylic acid (ACC) and ethylene in interorgan signaling during senescence in orchid (Cymbidium) flowers were investigated. Following application of radiolabeled ACC to the stigma or the rostellum (modified lobe of the stigma), radiolabeled ethylene is produced by all flower parts. In intact flowers as well as in excised central columns, stigma- or rostellum-applied ACC or [alpha]-aminoisobutyric acid were largely immobile. Local treatment of the central column of previously aminoethoxyvinylglycine-treated flowers with either ethylene or 2-chloroethylphosphonic acid (ethephon) rapidly induced emission of ethylene from the petals, showing that ethylene is readily translocated within the flower. Creation of alternative outlets (incisions) in the labellum or the central column significantly delayed the occurrence of senescence symptoms in ACC-treated flowers. The results do not confirm the presumed role of ACC as a signal in interorgan communication during flower senescence. In these flowers, ethylene produced in the stigmatic region following pollination or emasculation serves as a mobile factor responsible for senescence symptoms observed in other flower parts.