Ecofisiologia do crescimento e da produção do cafeeiro

Repeated and precise senescence measurements during the grain filling period using NIA revealed a high for senescence parameters and showed that different cultivars can differ for average senescence level or for onset of senescence and maximal rate of senescence. This result indicated that assesment of senescence at different stages (or thermal time values) of the grain filling period is needed to accurately address the time curve of senescence and it genetic variation. It has been suggested that the NIA method that integrates the change in color along the leaf blade takes better into account the non-uniform distribution of chlorophyll and consequently provides a more exact assesment of senescence (, ). In the present study NIA measurements allowed to identify associations between and senescence that were not detected by transmittance assessments. NIA measurements are definitely slower that transmittance measurements (few minutes for each measurement instead of few seconds) but do not requires specific equipment other than a digital camera and image analysis software that can eventually free download. This method, less adapted to large-scale screening than the transmittance method, appears more convenient, in turn, for precision phenotyping and for precise comparison of a limited number of genotypes.

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An interesting investigation that could make a good EEI is finding the relationship between density and weight%. This has been done for sucrose and the relationship is a cubic polynomial (see my graph below). The question is: does glucose have the same relationship? The method seems quite straight-forward: weigh out accurately 50 g glucose and add 50.0g water. Mix. This is a 50%w/w solution. Tare a 10 mL measuring cylinder and add the syrup up to the 10 mL mark. Note the mass and calculate the density. I'm sure you could work out a more accurate method. Try other mixtures: eg 20% up to 70%w/w. Plot (make sure you also measure the mass of 10 mL of water (ie 0% glucose) so you can plot that point too. For extra information see the article by Karen Peterson, Department of Chemistry, San Diego State University, California "Measuring the Density of a Sugar Solution" in Journal of Chemical Education, Vol. 85 No. 8 August 2008, pp1089-1090.


Senior Chemistry - Extended Experimental Investigations

Biophysical Characterization of the Underappreciated and Important Relationship Between Heart Rate Variability and Heart RateNov



Titanium is an amazing metal. It is strong, light and corrosion resistant. It can be alloyed with many metals to increase its range of applications for industrial, aerospace, recreational, and emerging markets. Its behaviour when anodised is remarkable. Anodizing titanium produces an oxide coating which generates an array of different colours, making it appealing for art, costume and body piercing jewellery and architecture (eg Guggenheim Museum). The color is an interference effect much like that in a soap bubble. The anodised colour depends on the voltage (see chart below). You could investigate the relationship between colour and voltage using different electrolytes. The big problem is getting 100 volts. Connecting a heap of 9v batteries in series might do the trick.