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Bu çalışma, 3-5 Kasım 1997 tarihleri arasında Antalya[Türkiye]'da düzenlenen International Symposium on Greenhouse Management for Better Yield and Quality in Mild Winter Climates'de bildiri olarak sunulmuştur. In this research, the effects of different growing media on lettuce production were investigated. Eight media made from the following materials perlite, pumice, fine sawdust, ground pine (Pinus brutia) bark and mixtures of these materials (1:1) were used. Seedlings with 3-4 leaves were transplanted in 4-liter pots filled with these substrates on 20 December 1995 and watered with a complete nutrient solution. To consider the effects of media on lettuce growing up to a certain time, all the lettuces, regardless of real harvest time, were harvested on 8 March 1996. Int Soc Horticultural Sci, Commiss Protected Cultivat

Most greenhouse climate models are specific for a particular combination of greenhouse type, crop, region and weather conditions. Models are formulated and validated for those conditions and it is not easy to directly extrapolate them to other, different conditions. In order to use them the coefficients need to be calibrated by experimental work, followed by validation of the adapted model. The main purpose of this work was the application of a formal dynamic climate model, defined and validated for heated greenhouses in continental regions of Spain, to non heated greenhouses in a mild winter region at the coast of Portugal. The original model was tested, adapted and validated so it simulated the microclimate inside unheated greenhouses. The methodology used enabled the problems to be identified, the model to be modified in a systematic way and then re-run to determine the improved performance. The new model includes new properties for some boundary components and sub-models for ventilation and stomatal resistance applicable to this greenhouse-crop system and new expressions for the convection heat transfer coefficients. In the validation process predicted and measured variables were compared graphically to show trends in the data and by using statistical parameters to characterise model performance. The model was validated with data representing different weather,ventilation operation and tomato crop conditions. Good agreement between predicted and measured data was obtained. It has been proved that this model can be used to estimate the greenhouse climate conditions, based on the weather conditions and on the greenhouse-crop system characteristics., La mayor parte de los modelos climáticos de invernaderos son formulados y verificados para aquellas condicionesconcretas en que fueron definidos, como son el tipo de invernadero, el cultivo y las características climáticas. Paraaplicarlos en condiciones distintas, los coeficientes de los modelos deben ser calibrados, proceso seguido de la correspondiente validación del modelo adaptado. El objetivo principal del presente trabajo fue la aplicación de un modeloclimático dinámico formal, definido y validado para invernaderos calefactados del interior de España con climacontinental, a invernaderos no calefactados de la costa de Portugal con clima templado. La metodología empleada eneste estudio permitió identificar los problemas del proceso de adaptación, modificando el modelo de una forma sistemática,para después determinar su comportamiento mejorado. El nuevo modelo climático incluye nuevas propiedadespara algunos componentes de contorno, nuevos submodelos para la ventilación y la resistencia estomática del sistema invernadero-cultivo, y nuevas expresiones para los coeficientes de transferencia convectiva de calor. Para elproceso de validación, se compararon las predicciones y las mediciones de las variables ambientales del invernaderode una forma gráfica y mediante el empleo de estadísticos. El modelo fue validado con datos representando diferentessituaciones climáticas, operaciones del sistema de ventilación y condiciones del cultivo de tomate. El ajuste entre los valores medidos y simulados fue bueno, lo cual prueba que el modelo puede ser usado para estimar el clima interiordel invernadero, en función de las condiciones climáticas externas y de las características del sistema invernadero-cultivo.

Three sheets of 10 surface area determinations were completed by 10 subjects using a nomogram and a formula. The formula was faster to calculate, 4.27 v 7.6 minutes for each sheet, and resulted in fewer serious errors (three v 30 errors).

To find out whether measurements of height made by health visitors are sufficiently accurate for use in routine screening of children we carried out an interobserver and intraobserver reliability study. Height measurements were made on a group of 10 children aged 3 years old and 10 aged 4.5 years old by two sets of four health visitors. They used a Microtoise or wall chart and the measurements were compared with those made by a trained auxologist with a Harpenden stadiometer. For a single assessment of height both pieces of equipment gave reasonably accurate results. In a child aged 3 years, with height measured on the Microtoise as 100 cm, the true height could be expected--with 95% probability--to lie between 99.2 cm-101.8 cm. At the age of 4.5 years, if the measurement was 110 cm, the child's true height could be expected to lie between 108.9 cm and 111.9 cm. The narrowest confidence interval for the growth rate from 3 to 4.5 years was achieved with the Microtoise, taking the mean of three measurements. We conclude that measurements made by health visitors are sufficiently accurate for routine screening of height, and the use of such measurements for the calculation of height velocity could be improved by more structured training.

Both biochemical and auxological measurements can be used to assess growth. Quality control in routinely reported in laboratory studies, but the reproducibility of height measurements, and the height velocity data derived from them, is seldom considered. We have previously established our error and in this report we examine its implications for the screening of short children and subsequent monitoring of their growth. The 95% confidence interval for height for a 5 year old observed to be on the 3rd centile for height, spanned the 2nd-4th centile. However, the confidence interval for a 12 month height velocity appropriate to such a child spanned the 8th-52nd centiles, the lower limit pathological and the upper more than satisfactory. A single height velocity even over 12 months therefore lacks the precision to provide a reliable index of current growth in short children. Furthermore, serial height velocity calculations on a cohort of 78 short normal children showed no significant correlation from year to year, suggesting that velocity is also unable to predict future growth. Although the proportion of this cohort of short children lying beneath the 25th centile for velocity remained constant from year to year, the identity of the individuals comprising that proportion changed, a phenomenon which could be largely accounted for by the random error associated with height velocity. Our data suggest that, by the time a trend in abnormal velocity is reliably established, a deviation from the height centiles is clearly evident. Although velocity charts are attractive in concept, they seem to be no more discriminating than height charts in practice, and may be clinically deceptive unless interpreted with great care.