Automated image analysis as a tool to quantify the colour and composition of rainbow trout (Oncorhynchus mykiss W.) cutlets

The goal of this paper is to propose and evaluate automated image analysis methods for describing muscle cutlets in rainbow trout. The proposed automated image analysis methods were tested on a total of 983 scanned images of trout cutlets, and included quality traits such as fat percentage, flesh colour and the size of morphologically distinguishable subparts of the cutlet. A sub-sample of 50 images was randomly selected for manual segmentation of the cutlet, the dorsal fat depot and the red muscle and regions. The identification of these regions by manual and automatic image analysis correlated strongly (r = 0.97, r = 0.95 and r = 0.91, respectively). The estimated fat percentage obtained from image analysis, based on the area of visible fat and the colour of the cutlet flesh, correlated well with chemical fat percentage measured by mid-infrared transmission spectroscopy (MIT) (r = 0.78). The automated image analysis methods are therefore a reliable means of predicting the fat percentage of trout cutlets. Principal component analysis (PCA) loading plots were used to identify subsets of variables from the image analysis of special significance for further studies; cutlet area, dorsal fat depot area, red muscle area, back height, cutlet width, and width of left and right abdomen wall were among the variables selected. PCA loading plots of different colour variables indicated that simple statistical coefficients such as percentiles and mean values can be used to quantify different aspects of flesh colour. In conclusion, the methods presented here provide a powerful toolbox for describing important morphological structures and quality traits of trout cutlets.     

Customer adapted grading of Scots pine sawn timber using a multivariate method

To define new grading rules, or to customize the ones in use in a rule-based automatic grading (RBAG) system of boards, is a time-consuming job for a sawmill engineer. This has the effect that changes are rarely made. The objective of this study was to continue the development of a method that replaces the calibration of grading rule settings by a holistic-subjective automatic grading, using multivariate models. The objective was also to investigate if this approach can improve sawmill profitability and at the same time have a satisfied customer. For the study, 323 Scots pine (Pinus sylvestris L.) boards were manually graded according to the preferences of an important customer. That is, a customer that regularly purchases significant volumes of sawn timber. This manual grading was seen as reference grading in this work. The same boards were also scanned and graded by a RBAG system, calibrated for the same customer. Multivariate models for prediction of board grade based on aggregated knot variables, obtained from the scanning, were calibrated using partial least squares regression. The results show that prediction of board grades by the multivariate models were more correct, with respect to the manual grading, than the grading by the RBAG system. The prediction of board grades based on multivariate models resulted in 76–87% of the boards graded correctly, according to the manual grading, while the corresponding number was 63% for the RBAG system.     

The fibrillar orientation in the S2-layer of wood fibres as determined by X-ray diffraction analysis

Summary It is the fibrillar orientation in the S2-layer which to a great extent determines the mechanical properties of the wood fibre, with regard both to strength and stiffness and to swelling properties. Measurements of the average fibril angle of fibres are not however easy and the results differ between the methods used. In order to evaluate in more detail how the fibril angle varies in spruce wood, an X-ray method based on diffraction from the 040-plane was developed. By comparison with microscopic examination it is concluded that reliable results relating to the fibrillar orientation in the S2-layer are obtained with the X-ray technique. It is shown that the fibril angle of mature wood is rather constant with regard to both age of the annual ring and its position in the height of the tree. The fibril angle of the earlywood is found to be only slightly higher than that of latewood fibres. It is also shown that compression wood may be easily identified by virtue of the fact that its fibril angle is much higher than that of normal mature wood.The authors thank Ms Ulla Jonsson for the microscopic measurements and Dr Anthony Bristow for the linguistic revision     

Vorläufige Untersuchungsergebnisse über die Lebensweise des PappelknospenwicklersSemasia oppressana Tr. und des PappeltriebwicklersSemasia aceriana Dup.

Ohne ZusammenfassungDie vorliegenden Untersuchungen wurden auf Anregung von Herrn Prof. Dr.-Ing. E. Schimitschek und mit Unterstützung der Landesforstverwaltungen Hessen und Schleswig-Holstein durchgeführt.     

Growth and nutrition of Betula pendula at different relative supply rates of zinc

Small birch plants (Betula pendula Roth) were cultivated in a hydroponic spray solution where the relative growth rate (R(G); day(-1)) was controlled by the relative supply rate of zinc (R(Zn); day(-1)). After an adjustment phase to steady-state growth, R(G) equaled R(Zn). The R(Zn) treatments were 0.05, 0.125 and 0.20 day(-1) with free access to all other nutrients. In an additional treatment, there was free access to all nutrients, including zinc (FA treatment). The pH of the nutrient solution was approximately 4.5 and conductivity was 100 &mgr;S cm(-1). The duration of each treatment depended on R(Zn) and ranged from 4 (FA treatment) to 10 weeks (at R(Zn) = 0.05 day(-1)). The plants showed persistent and typical zinc-deficiency symptoms at steady-state growth when R(G) was 0.05 and 0.125 day(-1), whereas there were few symptoms when R(G) was 0.2 day(-1). The Zn concentration of the plants ranged from 8 (at R(Zn) = 0.05 day(-1)) to 21 &mgr;g g(DM) (-1) (DM = dry mass) (at R(Zn) = 0.2 day(-1)) and was approximately 42 &mgr;g g(DM) (-1) in the FA treatment. Uptake rates of Zn, calculated per root growth rate (&mgr;mol g(DM, root) (-1)), were about 2.8 times higher at R(Zn) = 0.20 day(-1) than at R(Zn)= 0.05 day(-1). The root and stem biomass fractions were approximately constant at all supply rates of Zn, whereas the leaf biomass fraction tended to increase with increasing supply rate of Zn. Net assimilation rate was constant from FA to an R(Zn) of 0.125 day(-1) but decreased by a factor of about 2 at R(Zn) = 0.05 day(-1). Leaf area ratio and specific leaf area were smaller at low supply rates of zinc than at high supply rates.