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In farming of fruit trees it is of interest to know the light interception of the trees. Therefore, in this project, a geometric model of the trees was derived using LiDAR data and this was combined with a sky model to estimate the light interceptionof orchard trees. The light interception was estimated by first synthesising a discrete model of the hemispherical sky, which holds a measure of global lightradiation in each node. The light interception of the trees was then estimated by ray tracing from the sky, applying a radiation absorption model where rays passed the point cloud representation of the trees. Comparing the interception model to measurements of photosynthetically active radiation (PAR) underneath a tree, the qualitative agreement was high and the quantitative analysis showed a reasonable, albeit noisy, correspondence between the model output and the real world measurements. When comparing the estimations produced by the solar-geometry model and the tree volume (estimated also with LiDAR), a correspondence between the surface area of the tree and the interception was found. When comparing tree volume and light interception against actual yield numbers (total weight, average fruit weight and fruit count per tree), the observable trend was that light interception did better in predicting the average fruit size, while the volume did a better job of estimating the two others. The results were encouraging, however, because ground truth data were only available for 18 trees, future work will have to compare with a greater number of measurements over multiple growing seasons.

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Call number: LD2668 .T4 1950 Z4 / Master of Science

Bian Xue Lin. / Thesis (Ph.D.)--Chinese University of Hong Kong, 2001. / Includes bibliographical references (p. 189-208). / Electronic reproduction. Hong Kong : Chinese University of Hong Kong, [2012] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Mode of access: World Wide Web.

There is a well-established link between F&V and health, and are an essential part of a balanced diet and healthy lifestyle. They are rich in essential nutrients that are believed to promote good health, such as vitamins, minerals, fibre, and phytochemicals. Due to the low adherence to F&V recommendation among people across all ages, it is essential to tackle this problem - especially among children. One way to achieve this is to gain a good understanding of the relationship between F&V intake and health parameters; this will help emphasise the importance of consuming the recommend five-a-day for the whole family. In addition, the younger generation should be provided with nutritional education regarding their food choices, including snacks. The investigation in this thesis focuses on children's F&V intake and healthy snack awareness and its relationship with measured health parameters, as currently very little is known about this relationship, particularly among Scottish children. To this end, six studies were conducted and are presented here. The first and second studies examined the relationship between F&V intake and health parameters using a combination of longitudinal and cross-sectional data (n=475 and 466, respectively) from children of primary school age (5 to 12 in Aberdeenshire). Parents completed either a seven-day total food intake questionnaire - dietary record (TFIQ) or a two-day fruit and vegetable questionnaire (FVQ) on behalf of their children. Health parameters (weight, height, body fat, waist/hip circumference, blood pressure and lung function) were measured at their school. Higher F&V intake was correlated with improved health parameters when using the two-day FVQ. These are summarised as follows: lowered systolic blood pressure, some measures of lung function and reduced weight, body fat, waist circumference, hip circumference, waist to hip ratio and waist to height ratio. Of note, the health parameters did not appear correlated with F&V intake measured using the seven-day TFIQ, with the exception of a negative relationship with blood pressure when using the longitudinal data. F&V intake using two instruments (seven-day TFIQ and two-day FVQ) was compared in the third study within the same individuals (primary school children, n=51). The estimated portions of F&V using the focused (two-day) FVQ was higher than the seven-day TFIQ. It is unclear whether parents tended to overestimate their children's F&V intake using the FVQ or under-estimate it using the TFIQ. These studies led to the fourth study, which focused on identifying biomarkers of F&V intake using the new technique of metabolomics - liquid chromatography/mass spectrometry (LC/MS), using urine samples collected from the children. This involved correlating biomarkers in urine with children's F&V intake as measured by the FVQ. Participants included 29 primary age children, recruited as a part of the cross sectional F&V study in Chapter Two. The findings revealed 15 food/F&V biomarkers, excluding food/F&V biomarkers (n=5) that reflected children's dietary behaviour which was identified as a result of the significant correlation with children's F&V intake. The identified biomarkers which were revealed from two different approaches - stepwise regression and literature searching - are as follows: citric acid; benzoic acid; 2-Pyrrolidinone; Glycine; Alanine; N-Nitrosopyrrolidine; Isocitric acid; Isocitrate; 1-Acetoxypinoresino; Proline betaine; Adenosine; Adenine; Hippuric acid; Carnitine, and Ethanol. Children's F&V intake was correlated with three urinary metabolites (4, 427, 109) in which very few correlations (n=4, one positive and three negative correlations) were significant. These correlations that compared the identified biomarker with what was reported in the FVQ were generally poor in terms of not showing agreement with children's F&V intake. One exception was the positive correlation that was found with the urinary excretion of gamma guanidinobutyric acid, which may reflect children's fruit intake. Urinary excretion of formic acid, butanoic acid and 1-propanamine were all negatively correlated with children's F&V intake and were used as a robust biomarker of fruit and dairy products among children. With the use of the metabolomics technique, there is more precision in children's dietary profile presentation compared with relying on a single method, such as the FVQ. Metabolomics has the potential to be used as a validation/reference tool and in detecting novel biomarkers. A fifth study was carried out to explore children's perceptions of snack healthiness and snack preferences, and the relationship between these and their health parameters. Participants were children of nursery and primary age (3-12 years old, n=472). A card sorting exercise was implemented using 18 popular snack types, and basic health parameters (weight, height, body fat, waist/hip circumference), both of which were measured in the children's school. The children showed good understanding of snack healthiness based on the nutritional composition of the 18 snacks, and the findings showed that as children develop, their perception of healthiness increases. Nevertheless, the unhealthier snacks were still the most preferable type to children. A follow-up study was conducted to examine parents' (n=142) views on snack healthiness and snack preferences for their children. Participants were parents of nursery and primary school age children. An online survey was designed and implemented as a tool for data collection. Parents exhibited a good awareness of healthy snacks, however stated that their children showed more preference for unhealthy snacks. There was no statistically significant relationship between parents' knowledge of snack healthiness and their age, sex, education level, employment status and ethnicity. Although parents demonstrated that nutritional value is one of the most important goals for them in snack selection for their children, taste and peer pressure are two factors that significantly affected children's snack choice. It is still not clear why the parents' snack choices were not always the healthy choice. Overall, the findings from the above-conducted studies demonstrated that: 1) Scottish children still do not adhere to the five-a-day recommendation; 2) some aspects of children's health were correlated to their F&V intake when using a focused two-day FVQ, and expressed more F&V intake for their children when the focus was on the two-day FVQ; 3) urine metabolomics has potential for identifying biomarkers of F&V intake; 4) both children and their parents showed a good perception and knowledge of what constitutes a healthy snack - even children of nursery age were able to differentiate between healthy and unhealthy types; 5) nevertheless, children's eating habits (particularly towards snack preference) need to be improved. It is hoped that these data will aid in the production and testing of further hypotheses related to short- and long-term health in children.