PhD, EngD, DM and MSc by research theses (Silsoe)
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Item Open Access Alternative chemical control of anthracnose and crown rot of banana caused by Colletotrichum musae(2000-11) Khan, Sabir Hussain; Aked, JuliaChemical alternatives to the fungicides currently used to control Colletotrichum musae infections on banana fruit have been investigated. Four isolates of C. musae cultured from anthracnose lesions on imported banana fruit were screened against the fungicides thiabendazole (TBZ) and imazalil incorporated into malt extract agar (MEA). Two of the isolates showed some tolerance to TBZ even at 1.24 mM (250 ppm), whereas all four isolates were very sensitive to imazalil at concentrations of > 0.017 mM (5 ppm). One susceptible (CM100) and one tolerant (CM103) isolate (to TBZ) was selected. Eleven chemicals were evaluated over a range of concentrations for their effectiveness in inhibiting the germination and mycelial growth of these isolates in vitro (on MEA). The chemicals were the antioxidants ascorbic acid, propionic acid, benzoic acid, butylated hydroxyanisole (BHA), butylated hydroxytoluene (BHT), propyl paraben (PP), propyl gallate (PG), dimethyl sulphoxide (DMSO), thiourea and tannic acid and the natural plant product azadiractin. BHA, azadiractin, benzoic acid, PP and PG gave the highest levels of fungal inhibition in vitro. BHA at 5 mM completely inhibited the germination and mycelial growth of CM100 and CM 103 at 25°C. BHA (1 mM) in combinations with benzoic acid (1 mM), PP (1 mM) or imazalil (1.68 pM) completely inhibited germination and mycelial growth of CM103 at 14 and 25°C. The effectiveness of imazalil was not affected by the pH of the medium whereas the effectiveness of BHA was greatest at pH 3.5 and 6.5 and benzoic acid was more effective at lower pH values. C. musae was shown to produce nine extracellular enzymes in liquid medium which have not been reported before including lipases, phosphatases and hydrolases. BHA, imazalil and TBZ caused differential inhibition of the production or activity of these enzymes. The toxicity of selected chemicals was tested against anthracnose or crown rot infections of fingers or hands of banana fruits. Inoculations of C. musae were made with either mycelium in wounds in the banana peel or with conidia on the intact surface of the fruit or on the cut stalk or crown tissues. Of the alternative chemicals tested on their own, BHA and azadiractin gave the greatest inhibition of anthracnose and crown rot infections with dip treatments at 1 mM giving control levels ranging from 10-39% compared with 17.6-38.3% for imazalil (0.84 mM = 250 ppm). BHA (5 mM) in combinations with imazalil (0.84 mM), PP (10 mM) or benzoic acid (10 mM) suppressed anthracnose lesions (CM103) by 64.7, 54.9 and 35.3 %, and crown rot development by 70.5, 62.3 and 42.6 % at 25°C respectively. At 14°C these same combinations gave complete control of anthracnose lesions and crown rot development. TBZ was less effective at controlling crown rot (CM100 or CM 103) than imazalil alone or when in combinations with BHA. Combinations of BHA with imazalil but not with TBZ showed synergism both in vitro and in vivo. The cost/litre of the best trial treatment (BHA at 5 mM with imazalil at 0.84 mM) was less than that of imazalil at 1.68 mM (500 ppm). This suggests that food grade phenolic antioxidants such as BHA may be useful adjuncts to currently used fungicides such as imazalil for commercial control of banana postharvest diseases.Item Open Access Application of GIS and remote sensing for land use planning in the arid areas of Jordan(2000-01) Ziadat, Feras M.; Taylor, J. C.Land suitability analysis formed part of a land use planning exercise in a development project aimed at improving agricultural productivity in the transitional Badia region of Jordan. Soil observations and soil maps were available at three levels of detail with differing coverage: level one (1:250,000 scale -complete cover), level two (1:50,000 scale - part cover) and level three (1:10,000 scale very limited cover). The development project selected the FAO Framework for Land Evaluation as the basis for land suitability analysis. This research investigated seven different calculation approaches for the processing of soil observations within soil map polygons using a GIS to derive land suitability ratings. These methods either use the soil observations to calculate the suitability of each soil mapping polygon or an interpolation technique (Voronoi diagram or Triangulated Irregular Network) between observation points. The overall map purity and homogeneity with respect to land characteristics were used to evaluate these methods. The quality of suitability maps varied according to the level of soil mapping and the method of processing the soil observations. The relative performance of the processing methods is discussed and recommendations for each level of mapping are proposed. The results showed that the purity of suitability maps was between 60 and 70% at the highest level of detail. Thus they should be used with caution for site specific analyses. Statements of map quality should be appended to suitability maps. The soil maps and observation points were derived and collected in a previous soil survey programme and georeferenced by map reading before the widespread availability of the Global Positioning System (GPS). When the data were integrated and overlaid on a satellite image within a GIS, a number of inconsistencies in georeferencing the data and in the attributes attached to them were revealed. Investigation and correction of these evolved into a major component of this work. Systematic errors caused by the use of different datums to georeference soil maps and observation points in the Jordan Soil and Climate Information System (JOSCIS) were detected. The map reading procedure also caused unsystematic errors in the locations of soil observations, which were re-measured at a sample of original observation sites using GPS. The correction of the unsystematic errors was not feasible due to the difficulty and cost of relocating all observation points. Errors in the attributes attached to the observation points were caused by survey recording procedures, highlighting the need for an examination of the data before analysis. The systematic and attribute errors were corrected and the implication for suitability analysis examined. The areas and spatial distribution of different suitability classes were affected increasingly as the level of mapping became more detailed. The presence of all these errors was sufficient to create errors in the derived land suitability maps, which could lead to incorrect land use planning decisions. The integration of satellite imagery, soil observations and soil mapping polygons within a GIS was indispensable for quality control of the data. The highest purities of suitability maps using existing soil mapping polygons were between 60% to 70% at level three but they only covered veiy limited areas. This indicated the need to extend mapping at this detail for site-specific planning and if possible, to increase the purity of soil mapping units. This was investigated by integrating satellite imagery and topographic data in a GIS. A 3-D perspective view of a Landsat TM image using an air photo-derived DEM was the most promising way of using the available data. Further research is needed to investigate the interactive use of air photo-derived DEMs and Landsat images, with more focus applied to site specific planning and field verification of the technique. Although this work was necessarily focussed on the issues and problems particular to one data set used in a Jordanian context, a number of general lessons have been learned. Firstly, careful examination of all input data is necessary to eliminate georeferencing and attribute errors. Secondly, overlay of input data onto a geocoded satellite image is extremely useful for detecting potential sources of input data errors and is recommended. And thirdly, GIS is indispensable for investigating existing data for errors and exploring new methods of analysis.Item Open Access Assessment of crop performance potential using remote sensing(1992) Zmuda, A. D.; Taylor, J. C.This report demonstrates the potential use of optical remote sensing for monitoring the growth and development of winter sown wheat at the field scale. Spectral vegetation indices have been shown to be correlated to important agronomic variables i.e. Leaf Area Index, per cent cover, intercepted solar radiation and grain yield. For winter sown cereals, relationships to grain yield at harvest have been proposed at various times during the growth of the crop. However the precise timing of the remotely sensed input to such models has not received investigation in relation to sowing date, variety and development stage. Further the effect of fungal diseases on such models is not well understood. To address these problems, commercial agronomy trials were used to monitor the reflectance patterns of winter wheat over two growing seasons. During growth and development of the crop, the wheat was destructively sampled and the apex development stage was recorded. Key stages of apex development were found in which spectral data was correlated to grain yield. The relationships were found to be complex in relation to sowing date, variety and fungicide treatment and may therefore not be applicable on a year to year basis.Item Open Access An attempt to extend means-end theory: An investigation of the linkages between choice behaviour and values(2003-04) Manyiwa, Simon; Crawford, I. M.The research problem was identified as a lack of means - end theory linking choice behaviour to values. The aim of the study was, therefore, to determine whether or not the means-end theory could be extended to linking choice behaviour to values. The research was focused on the following two research questions: ( 1 ) what , if any, are the conceptual categories in the means-end theory linking choice behaviour to values? (2) How, if at all, are the conceptual categories in the means-end theory linking choice behaviour to values connected together? A case research method was adopted for the empirical investigation of the study, focusing on food choices in the family context. The fieldwork, carried out in the UK, was done in two phases, i.e. the pilot study and the main study. The research findings suggest that the conceptual categories linking choice behaviour to values consist of the following conceptual categories: choice behaviour, attributes of choices, consequences, and values. In addition, the research findings indicate more dominant direct linkages between the adjacent conceptual categories than between the nonadjacent conceptual categories. The dominant direct linkages between the adjacent conceptual categories suggest that the conceptual categories linking choice behaviour to values are hierarchically connected together. The main implication of the research findings is that researchers can establish linkages between choice behaviour and values on the basis of actual choices in specific social contexts, instead of using cognitions as a surrogate for choice behaviour.Item Open Access Biological and artificial receptors in affinity sensor for water toxins detection(2003-01) Lotierzo, Manuela; Tothill, Ibtisam E.Molecular recognition is the basis for many of the chemical and biochemical phenomena occurring in living organisms. For example, antibodies, which are one of the different classes of natural receptor molecules, are capable of selectively recognising a specific target molecule or structure. They are therefore routinely utilised as analytical reagents in clinical and research laboratories. The design and synthesis of biomimetic recognition systems, capable of binding target molecules with affinities and specificities comparable to natural receptors, is regarded as one of the greatest challenges in bioorganic chemistry. Molecularly imprinted polymers (MIPs) have been shown to mimic the binding sites of antibodies and are, therefore, constantly gaining in interest for applications based on specific molecular recognition. This project aimed to develop affinity sensors for the detection of algal and cyanobacterial toxins such as microcystin-LR and domoic acid in water samples. Following the investigation, a heterogeneous direct competitive enzyme-linked immunosorbent assay (ELISA) format for microcystin detection was developed. The system was then transferred to an affinity membrane sorbent based ELISA. This was an amenable format for immunoassay incorporation into a disposable amperometric immunosensor device. A three-electrode system immunosensor was fabricated using thick film screenprinting technology. Amperometric HRP transduction of hydrogen peroxide catalysis, at low reducing potentials, versus Ag/AgCl reference and carbon counter electrode, was facilitated by hydroquinone mediated electron transfer. A detection limit of 0.5 pg V1 for microcystin-LR was achieved. The work undertaken also describes the design and synthesis of biomimetic recognition systems based on MIP, capable of binding target molecules with affinities and specificities on a par with natural receptors. A MIP synthetic receptor selective for microcystin-LR was studied using an enzyme-linked competitive assay and found to be comparable to polyclonal antibodies, whilst the MIP had superior stability over natural receptors. Methacrylic acid based MIP had a detection limit of 1 pg I'1, approxilately twenty times higher than that of anti microcystin-LR polyclonal antibody. A molecularly imprinted polymer was also directly synthesised by grafting on the gold chip of a surface plasmon resonance (SPR) based bioanalytical instrument system: the BIAcore 3000™. Such a chip based platform allowed a simple test of the specific MIP receptor for the marine toxin domoic acid. A fiill characterisation of the grafting procedure was initially carried out on a bare gold surface, and each step of the polymerisation was investigated by contact angle measurements and AFM imaging. The surface photo-initiated MIP film was obtained and its thickness and homogeneity evaluated. Domoic acid is a molecule that is too small for direct analysis, hence a competition reaction was performed in presence of the conjugate DA-HRP and a detection limit of 2 fig f 1 could be achieved with the BIAcore 3000™ system.Item Open Access Calibration of pesticide leaching models(2002-09) Dubus, Igor G.; Brown, Colin D.Complex deterministic models are being used within the context of pesticide registration to assess the potential for crop protection products to impact on the environment. Although calibration is in many ways at the heart of pesticide fate modelling, it has received little attention in the past. Sensitivity analyses were carried out for the four main leaching models used for pesticide registration in Europe (PELMO, PRZM, PESTLA and MACRO) using four different leaching scenarios and two approaches to sensitivity assessment (one-at-a-time and Monte Carlo sensitivity analyses). Also, an inverse modelling approach was used to estimate values for sorption and degradation parameters from leaching data for seven lysimeters using the PESTRAS model. The overall conclusions of the PhD can be summarised as follows: 1. Sensitivity analyses for the four leaching models mainly used for pesticide registration in Europe demonstrated that predictions for pesticide loss are most sensitive to parameters related to sorption and degradation. In a small number of scenarios, hydrological parameters were found to also have a large influence on predictions for pesticide loss. 2. Sensitivity analysis proved to be an effective approach not only for ranking parameters according to their influence on model predictions, but also for investigating model behaviour in a more general context. However, the research questioned the robustness of the Monte Carlo approach to sensitivity analysis as issues of replicability were uncovered. 3. Inverse modelling exercises demonstrated that non-uniqueness is likely to be widespread in the calibration of pesticide leaching models. Correlation between parameters within the modelling, such as that between sorption and degradation parameters when predicting pesticide leaching, may prevent the robust derivation of values through an inverse modelling approach. Depending on the calibration system considered, these parameters may act as fitting variables and integrate inaccuracies, uncertainties and limitations associated with experimental data, modelling and calibration. 4. A special implementation of error surface analysis termed lattice modelling was proposed in the PhD as an efficient technique to i) assess the likely extent of nonuniqueness issues in the calibration of pesticide leaching models; and, ii) replace traditional parameter estimation procedures where non-uniqueness is expected. Care should be exercised when assessing the results obtained by both modelling and inverse modelling studies. Suggestions to improve the reliability in the calibration of pesticide leaching models have been proposed.Item Open Access Comparison of soil compaction below wheels and tracks(2005-10-19) Ansorge, Dirk; Godwin, R. J.This study investigated the effect of high axle loads carried on self propelled wheels and tracks on soil bulk density, soil deformation, rut depth, and penetrometer resistance under controlled laboratory conditions. Furthermore pressure distribution below a three and a two idler track was measured. A brief field study was also conducted to compare the results gained under laboratory conditions. The benefit of the “Terra Trac” driving systems compared to wheel type systems was clearly shown in uniform and stratified soil conditions. Soil deformation was reduced to 50 % for the tracks compared to the wheels at an overall load of 12 t and 10.5 t, respectively. Penetrometer resistance showed a very high resistance close to the surface for the tracks. In uniform soil conditions there was no significant increase in penetrometer resistance compared to the control below 400 mm depth. Reducing the inflation pressure to half the recommended inflation pressure reduced soil deformation by 25 %. Three passes of a tire increased soil density by 20 % compared to a single pass. The three idler track showed only a 50 % increase in pressure from the front to the rear sprocket compared to a 100 % increase for the two idler track. Single peaks in pressure below each idler were less pronounced for the three idler track. Unfortunately the advantage in the pressure distribution for the three idler track did not lead to significant improved behavior concerning soil compaction. The advantage of a tracked combine compared to a wheeled combine is also shown in field measurements. The root system of oil seed rape in former track ruts is more developed than in former wheel ruts. Soil physical properties after the passage were compared to the predictions of two models. The tendency was correct, however the real values were largely offset.Item Open Access Continuous mass flow measurement of granular materials(1997-10) Saunders, Stuart P.; Godwin, R. J.This thesis reports on the development of a double inclined plane (DIP) transducer system based upon the principles of force reaction. This transducer had a design specification to measure the true mass of “free” flowing granular materials, primarily agricultural crops, with an accuracy of ± 2 % on total mass flowed for flow rates between 1 and 10 kg/s. Two absolute values are used to assess accuracy in this study, (i) the total mass flowed (kg), a measure of the mass accumulation and, (ii) the mass flow rate (kg/s), a ‘spot’ reading of flow rate. The performance of the novel system has been evaluated through theoretical, laboratory and field studies and consideration has been given to the commercial and business aspects of the manufacture, marketing and further development of the device. Following mathematical and laboratory studies of the sponsors current force reaction transducer - a single reaction device, angular variations were highlighted as having a significant effect upon output. A further study found that the least sensitive reaction plate angle was 55° To overcome this problem, the double inclined plane (DIP) concept was developed, 2 single reaction plates, joined along their apexes, angled at 55 degrees to the horizontal, mounted upon a horizontal strain gauged beam. Angular compensation when tilting the transducer was provided by generating a higher force from the shallower face and a lower force from the steeper face. A mathematical model of the new transducer allowed the output to be predicted to within 1.7 %. Initial calibration was undertaken in the laboratory and tested using a combine clean grain system simulation apparatus. In-situ machine studies were performed by mounting the transducer in a New Holland TF42 combine, firstly on an extended bubble up auger and finally in the drop box, between the clean grain elevator and bubble up auger. Initial pilot studies were conducted with the combine static to calibrate the system and finally a full harvest field trial was undertaken. Over the harvest field trial, the accuracy on accumulated mass was better than 0.9 % over 127 tonnes. Tramline effects upon transducer output were found to be self cancelling, as the resulting positive and negative ‘spikes’ in the signal, when summed over time approximated to zero. Changes in pitch angle, up to 10 degree caused between 1.5 and -2.8 % randomly distributed error. Roll angles up to 7.5 degrees, caused between -0.9 % and 1.7 % randomly distributed error in static trials. Field beans and oilseed rape required calibration constants 6.8 % and 3.1 % lower than that for 12.5 % moisture content wheat, but with adjusted calibration constants, gave excellent repeatable results. Increasing moisture contents of up to 30 % in wheat resulted in the transducer under reading by, on average, 1.6 %. An assessment of manufacturing costs was made and the unit cost was £154.12 each for 30 units reducing to £109.59 each for 3000 units. It is recommended a pricing objective of maximising sales growth is used which will position the device at the less expensive end of the market. Due to commercial sensitivity, a draft patent has been written to protect the DIP concept. The first stages of commercial adoption already being undertaken by a major multi-national agricultural machinery company, who are evaluating a pre-production prototype. This thesis provides the systems, data and principles required to create a novel, commercially practical transducer system, based upon the principles of force reaction. The problem of angular compensation has been overcome in a simple and effective manner offering a relatively inexpensive but accurate method of measuring mass flow rate, which has already received commercial interest.Item Open Access Controlled and modified atmosphere storage of tomatoes(1995-07) Batu, Ali; Thompson, A. KeithFrom the literature it was concluded that various factors could influence the storage life of tomatoes. These included harvest maturity, storage temperature, storage humidity and the level of gases in the storage atmosphere using modified atmosphere packaging (MAP) and controlled atmosphere storage (CAS). However, what was not clear from the literature was how (many of) these factors interacted and there was little information on the effect at long term MAP or CAS on eating quality of tomatoes. A series of experiments were, therefore, carried out to investigate the above factors. In order to carry out experiments preliminary tests were performed on tomatoes and compared to those given in the literature. These were to establish relevant quality criteria for the fruit in order to judge the comparative effects of the various treatments and included a texture measuring test and minimum criteria for objective colour measurements. Storage humidity was shown to interact with fruit harvest maturity in that ripening time of fruits increased in high humidity levels. The quality of tomatoes harvested at the mature green stage of development and stored in low or medium humidity was approximately the same when they were ripe. However, fruit ripened at high humidity had a significantly better colour, were more acidic and firmer than those ripened at low humidities. Tomatoes harvested at the pink stage of maturity and ripened at low humidity levels were firmer, probably because the time taken to ripen was shorter than those ripened in medium and high humidity. There were interactions between MAP and temperature in that MAP was more effective in delaying ripening at 13°C than at 20°C. MAP interacted also with tomato harvest maturity where it was more effective in delaying ripening of fruit harvested at the mature green stage of maturity. Colour development was affected by storage temperature. In storage at 13°C maximum reddening occurred about 10 days later than in those stored at 20°C. There was an interaction between packaging films and ripening time of fruits. Tomatoes ripened later when they were sealed in films which were less permeable to O2 , CO2 and water vapour than when they were sealed in higher permeable films. Packaging films also affected fruit firmness of tomatoes. All green tomatoes sealed in 25 micron thick polypropylene (PP) film were very firm even after 60 days of storage at 13°C or 20°C, compared to other films. Ripening time and subsequent quality of fruits were influenced by their harvest maturity. Tomatoes harvested at the mature green stage and sealed in 50 micron thick polyethylene (PE50) or PP films had delayed development of the red colour after 30 days of storage and those tomatoes also had the lowest weight loss and the highest soluble solids after 60 days of storage. Storage temperature affected the acidity and total soluble solids (TSS) contents of fruits. These were higher at 13°C than at 20°C for those harvested at either the mature green or pink stage. The CO2 levels affected the colour changes of the tomatoes. The colour of tomatoes harvested at the pink stage of maturity did not change when they were stored in 6.4 % CO2 with 5.5 % O2 and 9.1 % CO2 with 5.5 % O2 even after 50 days and in some cases after 70 days storage. The red colour development of the tomatoes exposed to less than 6.4 % CO2 increased, whereas red colour (Minolta a*.b*-1 values) decreased with CO2 levels above 9.1 % during storage. There were differences in ripening of tomatoes between MAP and CAS where mature green fruits in MAP ripened earlier than the same fruits in CAS. The differences were probably due to ethylene accumulation in MAP which would not occur in CAS because of the continuous gas flushing. It was concluded that with the combination of reduced temperature and MAP or CAS, fruit could be stored for 60 or 70 days and still be marketable in terms of appearance, firmness, flavour and overall acceptability.Item Open Access Design of a novel punch planter capable of producing equidistant seed spacing of irregular shaped seeds(2002-09) De Resende, Ricardo Capucio; Brighton, James L.Plants uniformly spaced in the field have a more efficient use of resources, due to their even distribution. There are also a better ability to compete against weeds, less spread of disease and lodging. Consequently the yield should be improved. Precise seed placement and seed location in the field are important for the management of the crop at a plant-scale level, for such operations as mechanical weeding or herbicides applications. A novel concept of a precision drill was developed to achieve an advanced control of seed placement and location in the soil. The fundamental principle adopted, was to trap seeds inside holes in the soil, to eliminate seed bounce and roll in the furrow. The concept is simple and consists of only three moving parts, two punch wheels and a fen, to precisely place the seeds in the soil. A rotary punch planter prototype was designed and built, including a vacuum operated seed metering unit and an air delivery system. The prototype was tested under laboratory conditions to determine its performance in relation to seed placement, when planting wheat and pelleted sugar beet seeds. The experiments were done in a soil bin at 4, 6 and 8 km/h Seed spacing and depth were set to 18 cm and 3 cm, respectively. The results show that, once a seed had been successfully selected the prototype had the ability to precisely place seeds in the soil for wheat and sugar beet seeds, at all speeds tested. The grand mean for precision was 12.2%. The CP3 value for wheat and sugar beet at 8 km/h were 26.2 % and 60.8 %, respectively. The main problems encountered were seed selection at higher speeds, and incorrect seed transfers from the seed metering unit to the delivery punches, which occurred for both seeds at all speeds. The concept has proved to be effective and modifications of the seed metering mechanism to improve its performance is recommended to further improve upon the concept.Item Open Access The design of an improved efficiency lavender harvester(2005-01) Dimitriadis, Christos I.; Brighton, James L.The introduction of new methods to solve a specific task was always the ignition for the human mind to find new solutions. Considering the new demands in mechanical lavender harvest for oil production a novel harvester has been developed employing the stripping technique (Klinner et al., 1986a,b,c,d; Hobson et al., 1988) developed for the harv~~ting of cereals. The harvester works in a unique way for this crop by removing the flower :~eads_ in the field, leaving the majority of the stems intact. Convention~! harvesting methods such as hand harvest and mechanical harvest using a . cutting mechanism collects both the flower head and a cut length of the stem. This was found to be an inefficient method for the harvest of lavender because most of the oil produced by the plant (97.5 % by weight - Venskutonis, 1997) is located on the flower. Also using these methods the amount of stem collected increases the transportation and the distillation costs, generates more demanding designs, and removes the stem from the field that could otherwise be left as a natural nutrient. Taking this into account and that the British Pharmacopoeia directs that in making the most refined lavender oil (for medicinal use) it should be distilled from the flowers after they have been separated (stripped) from their stalks (Grieve, 2001) the proposed harvesting technique is ideal for the production of high quality lavender oil.Item Open Access Design of the robotic self-travelling sprinkler system(1999-08) Ozaki, Yuriko; Blackmore, S.A conventional rain gun system is adversely affected by windy conditions. Therefore, the robotic self-travelling sprinkler (STS) system that controls the head and the water supply with relation to instant windy conditions. The robotic STS head has two degrees of freedom; sector and trajectory angles, driven by stepper motors to follow the control model, which are found by applying prediction models of water distribution, Centre of volume and Semi-empirical models. As a result, it was shown that the control for the sector angle compensated for the horizontal water distortion from wind, however, the trajectory angle was found to need more data to model the optimum trajectory angle. To control the water supply, a cut-off solenoid valve was installed and shut when wind was over 6 m/s upwind and 7 m/s downwind. This indicated that the trajectory angle was less than 10 degrees above horizontal. Under such windy conditions, water can not be distributed as far from the STS as required or becomes spray, which cannot reach to the ground. As the experimental results showed, the system enabled to minimize the commercially ineffective water distribution. A chemigation system was added, which can injects chemicals into the main water flow. The system enables farmers to save the cost for extra chemigation equipment. The process of the system while working can be checked by the interactive communication system between the embedded computer and the user’s computer. Therefore, this system made the robotic STS system more reliable, furthermore, it enabled the user’s computer to read and save the data sent from the field controller unit. This robotic STS system can distribute water or chemicals to the required area, even if up to the irregular boundaries,(fence lines, comers of fields), with the minimum water supply. Also, the system is ready to incorporate treatment maps and DGPS. In other words, it is possible to feed the adequate amount of water or chemicals which varies depending on the different regions of fields, species of plants, and seasons.Item Open Access Detection of inappropriate cell proliferation in breast epithelium leading to breast cancer(2004-11) Degan, Simone A.; Woodman, Anthony C.; McCarthy, Keith; Bristol, James B.Breast cancer is predominantly caused by unrestrained cell proliferation. Proliferation is a complex process mediated by a network of signals that converge to a point called the ‘initiation of genome replication’ after which either proliferation or cell death could take place. The minichromosome maintenance (MCM) proteins are located at this point and play a pivotal role in regulating DNA replication. The detection of an aberrant level of such proteins can be of use in early breast cancer diagnosis. The main aim of this thesis was to propose a new system to detect inappropriate cell proliferation in breast epithelium. An in vitro model using cancer cell lines was developed to lay the foundation for subsequent studies employing human breast specimens. The application of the in vitro findings in breast excisions allowed assessing of the specificity and sensitivity of the biomarkers to ascertain slowly proliferating neoplastic cells. The most striking finding of this study was the abnormal presence of the MCM proteins in tumour compared to normal tissues with a typical pattern of expression unique for the histological classification of the lesion. The potential of MCM proteins as indicators of cell proliferation defects was further investigated with association studies with Ki-67, Bcl-2 and ER. MCM consistently identified a higher proportion of proliferating cells compared to Ki-67 suggesting that they are interesting markers of the Gi/S-phase. In fact, the MCM proteins start to co-localise in early Gi whereas Ki-67 is almost absent in this phase. Importantly, MCM proteins could recognise not only the proliferating compartment of the tumour but also those cells with replication potential. Based on these findings, the novel MCM biomarkers can be helpful in identifying both malignant and potentially malignant breast tissues. This feature can be useful in predicting patients at risk of tumour progression.Item Open Access Development and application of runoff model for ater harvesting in North East Nigeria.(1999-12) Audu, Idriss; Hess, Tim M.Rainfall in the northeast arid zone of Nigeria is limited and has been found to be declining over the last three decades (Hess et al., 1995). This problem of inadequate rainfall is further exacerbated by runoff especially on the degraded lands (fako). Such runoff-prone lands are potential areas for water harvesting. In dry years, harvested runoff water can considerably improve the environmental conditions for plant growth and can make the difference between death and survival. However, water conservation techniques will only show a benefit if the soil is able to hold the extra water within the root zone of the crops. A clear understanding of soil properties and moisture variations on these lands should provide the baseline information needed for applied soil and water management research. Aerial photographs and photo mosaics were used to identify several fako lands out of which three sites were selected for detailed study. The three sites were located at Jawa (12° 48.71’ N, 11° 02.21* E), Zurkaya (12° 49.15’ N, 11° 05.52’ E) and along Dumburi road (12° 54.31!N, 11° 07.49!E). The fako lands have compacted loamy and clay loamy soils with low infiltration rate and hydraulic conductivity. Dry bulk density values range between 1.34 gem¯³ to 1.61 gem¯³ and saturated hydraulic conductivity obtained were between 1 mm/h and 6 mm/h. Water retention characteristic curves revealed that the fako soils have good water holding capacity. Slopes are generally gentle and range from 0.1% to about 1%. Volume of water harvested depends on the runoff yield of an area. Models can be used to estimate runoff on the fako lands. The model to be used will depend upon the available information, the required accuracy and the resolution of the output and the time resources that can be directed at the modelling exercise. As the rainfall data available for the area is in daily time step, a model that can use daily rainfall as input to estimate runoff is required. In order to develop such a model, accurate rainfall-runoff records for several years should be obtained. High-resolution rainfall data for 13 site-years were collected between 1992 and 1994. The EUROSEM model (Morgan et al., 1992) was applied to simulate the rainfall events and partition them into overland flow and infiltrated water. The model was however calibrated and validated before being used for the simulations. For the calibration and validation, a rainfall simulator (USDA, 1972) was constructed and 32 rainfall-runoff events at intensities of between 25 mmh¯¹ and 169 mmh¯¹ were artificially generated on the three sites. A graph of measured versus simulated runoff events showed good agreements in both calibration and validation. Coefficients of determination and efficiency were 0.82 each in calibration and 0.83 and 0.74 in validation. Predicted runoff by the EUROSEM model was regressed against daily rainfall to obtain a linear regression model for predicting runoff from daily rainfall for the fako lands of north-east Nigeria. The model can be regarded as an integral expression of the physiographic and climatic characteristics that govern the relations between rainfall and runoff on the fako areas. Runoff coefficient and threshold value obtained for the area were 0.44 and 16 mm respectively. The linear model was compared to the curve number model and the runoff estimates by both models were similar. The developed linear model was combined with a water balance model, BALANCE (Hess, 1994) and applied to microcatchment water harvesting investigations. The BALANCE model was used to estimate the water balance components for the area. The Ritchie equation in the BALANCE model was calibrated and validated with field data. Measured versus predicted soil moisture plot gave R² values of 0.90 and 0.89 in calibration and validation respectively. Growth of neem tree (Azadirachta indica) on a typical fako land was simulated with different microcatchment sizes in three categories of years (dry, average and wet). Simulation results indicated that augmenting rainfall through runoff water harvesting technique could provide enough water to sustain growth and ensure rapid establishment of the neem tree seedlings. However, due to reduced dry spell some deep percolation may result during the peak of the rainy season (August - mid September) especially in wet years. A microcatchment size of 12m² (basin-runoff area ratio of 1: 2) was found to sustain year round survival of the tree and minimum drainage for all categories of years. Complementary to water harvesting in the conservation measure, effect of three soil cover treatments (bare, perforated polyethylene cover and solid polyethylene cover) on soil evaporation was investigated. As expected, the solid cover was found to have the most effect in reducing soil evaporation but this is not suitable in the current situation because it limits infiltration of rain and free air circulation. The perforated cover treatment is preferred as it can also significantly reduce soil evaporation and at the same time allow unrestricted infiltration of rain and free exchange of gases between the soil and atmosphere.Item Open Access The development of techniques of assessing soil compactability(1993-06) Earl, Richard; Spoor, GordonThe recent decline in farming profits has prompted an urgent need to increase efficiency, either by increasing outputs or reducing the cost of inputs. Soil compaction can influence adversely all stages of crop development, and hence yield, and is expensive to ameliorate in terms of time taken and power required. Minimum cultivation or direct drill crop establishment systems can reduce inputs, however, they are very susceptible to compaction from the previous season. There is a need to develop a greater understanding of the compactive nature of soil, and hence trafficability and workability, in relation to the selection of appropriate machinery to carry out agricultural operations. A study of research on soil compaction revealed that the majority of work to date has been carried out using disturbed soil samples in laboratory situations. The aim of this project is to develop techniques and models, based on field data, for assessing the susceptibility of soils to compaction by agricultural machinery. Work, conducted during this study, was carried out in the field in a range of soils, crops and climatic conditions. The study was approached by dividing the project into two sections:- (1) Prediction of trafficability and workability on a go/no-go basis. Soil water suction (h), soil moisture deficit (SMD) and cone penetration resistance were monitored at six field sites, under grass and an arable crop, covering a range of agricultural situations commonly found in central and eastern England. Strong correlations were found to occur between both h and SMD and:- (a) a qualitative assessment of soil condition, and (b) cone penetration resistance. These data formed the basis of models for predicting trafficability and workability at a given site on a particular day, and at any 5km square in England and Wales as an aid to business planning. (2) Assessment of the compactive nature of soil during loading. A methodology was developed which provides a measure of the susceptibility of soil to damage if land is trafficked when in an unsuitable condition. It is based on results of plate sinkage tests, in conjunction with those from confined compression tests, performed in the field using tractor-mounted equipment. Soil behaviour during compression was found to be governed by three phases:- (a) compaction with uniform lateral stress, (b) compaction with increasing lateral stress, and (c) displacement of soil laterally. Mathematical models are presented for predicting, for a given load and soil, the deformation phase and extent of disturbance likely to occur. The prediction models developed during this study provide a new approach to the selection of, and assessment of damage by, agricultural machinery.Item Open Access Early detection and monitoring of fuel leaks(2005-08) Huntley, Sharon L.; Setford, S.A novel integrated detection system· has been developed to protect the environment from hydrocarbon fuels leaking from large-scale storage facilities. Over the last decade, land and subsequent groundwater contamination from hydrocarbon fuels has been identified as the major threat to drinking water resources across Europe and the United States. The integrated system developed within this work has two main components: (1) 'Early warning' free-phase fuel leak detection sensors; (2) A novel immunoassay field test for rapid, in situ follow-up analysis of contaminated sites through determination of the extent of the contamination and early indication of dissolved-phase fuel migration. (1) A prototype optical reflectometric device has been developed, in conjunction with state-of the-art data acquisition and relay technology to provide a simple, low-cost hydrocarbons monitoring solution. In extensive field trials, this system has been evaluated as a multiple-array, sub-surface, remote leak detection and monitoring system for early detection of free-phase hydrocarbon contamination. The sensors respond to all. free phase hydrocarbons and can determine plume movement through soil. Preliminary leak information from these sensors can be combined with subsequent, quantitative site analysis using the immunoassay to provide an integrated, highly sensitive and low-cost solution for long term monitoring and analysis. (2) A novel ELISA has been developed for detection of the most controversial fuel oxygenate - \ methyl tert-butyl ether (MTBE), identified as the most major threat to groundwater (and consequently drinking water) resources above any other hydrocarbon contaminant. The ELISA is a classical competitive immunoassay involving free MTBE and a novel antigen consisting of an MTBE analogue covalently bound to BSA. The ELISA was optimised and transposed into a magnetic bead format, the detection range was 0.5-5000 ppm (IC50 5 ppm, assay time 65 minutes). Also detectable are MTBE degradation products TBA, TBF and alternative fuel oxygenates TAME, DIPE and ETBE. MTBE is highly soluble in water and so is an excellent marker for assessing the extent of site contamination. This integrated detection system potential provides a sensitive, cost-effective solution for early detection, analysis and surveillance of petroleum fuel contamination in a range of applications.Item Open Access Effects of 1-MCP on storage of "Queen cox" and "Bramley" apple fruit(2007) Dauny, Paul Trevor; Warner, P.; Joyce, Daryl C.Better maintenance of firmness and suppression of ethylene production in 'Queen Cox' and 'Bramley' apple [Ma/us sylvestris (L.) Mill. var. domestica (Borkh.) Mansf.] fruit was achieved by prestorage applications of 1-MCP. 1-MCP concentration, exposure time and exposure temperature ranges of 0.1 to 10.0 µl r1 1-MCP, 6 to 48 h and O to 20°C, respectively, were effective on fruit subsequently stored for 2 ('Cox') and 3 ('Bramley') months in air at 3 to 4°C. However, 1-MCP had little effect on either firmness or ethylene production after 4 ('Cox') or 6 ('Bramley') months storage. Nonetheless, 1-MCP treated 'Bramley' fruit had reduced rot and superficial scald incidence compared with untreated control fruit. 1-MCP application was most effective when applied within 24 h of harvest · compared to 14 d later. Earlier-harvested 'Cox' and 'Bramley' apple fruit showed better response to 1-MCP-treatment than those harvested towards the end of the picking season. 1-MCP-treatment was shown to improve apple storage alone and in combination with controlled atmosphere (CA) storage. Furthermore, 1-MCPtreatment maintained fruit quality during shelf-life better than CA storage alone. Chlorophyll fluorescence was not demonstrated to be an effective method to determine 'Cox' and 'Bramley' apple fruit quality. There was no recorded correlation between the concentration of five antifungal compounds and 1-MCP-treatment after inoculation with Penicillium expansum or Botrytis cinerea. 1-MCP treatment for apple storage was developed for AgroFresh Inc., the holder of the 1-MCP patent. Part of this research was used for the UK efficacy trials for registration of 1-MCP as an apple storage treatment. On the 18th July 2002 the US Environmental Protection Agency (EPA) granted approval for 1-MCP to be applied to food crops. Approval was granted in the UK in time for the 2003 apple harvest, and for 2004 across Europe.Item Open Access Electrochemical method for the rapid in situ screening of heavy metals in soil and water samples(2004-03) Cooper, Joanne; Setford, S.; Bolbot, J. A.; Saini, S.The aim of this work has been to develop a field-based electrochemical sensor for the detection of cadmium (Cd), lead (Pb), copper (Cu), zinc (Zn), arsenic (As) and mercury (Hg) in soil and water samples. In situ analysis, using rapid sample screening tools, can facilitate monitoring and remediation processes by minimising delays and substantially reducing costs. Disposable screen-printed electrodes (SPEs) have been fabricated using low-cost thick film technology. Carbon SPEs, coupled with anodic stripping voltammetry (ASV), provided a rapid, inexpensive in situ electrochemical screening sensor capable of simultaneously detecting Cd, Pb and Cu in soil and water samples in the microgram per liter range (pg I*1). A simplified soil extraction procedure, using 1 mol I'1 aqua regia and a three minute ultrasonic sample agitation, was developed for use with the sensor, addressing the lack of existing field-based soil extraction protocol. Extraction efficiency was evaluated using a soil certified reference material (CRM). Recoveries of 64%, 52% and 57% for Cd, Pb and Cu respectively were obtained, with a relative standard deviation (RSD) of <8% for all analytes (n=10). 82 soil samples were tested using the combined extraction + ASV sensor and compared against standard ICP-MS analysis. Correlation coefficients of 0.9782, 0.9728 and 0.9869 for Cd, Pb and Cu, respectively, indicated a good linear relationship between the two methods. A novel gold (Au) SPE, fabricated using a curable Au ink, was next evaluated for the detection of As and Hg. This is an improvement in the current state-of the-art as no surface modification or subsequent electrode adulteration to facilitate metal analyte depositioning is required. Furthermore, the Au ink can be cured at a low temperature (130°C), permitting electrode fabrication using disposable, cheap, plastic substrates. A patent has been filed. A limit of detection (LOD) of 2.7 pg I"1 and 1 pg I"1 for As3+ and Hg2+, respectively, was obtained following a 30 s depositioning. Speciation measurements for As were performed by reducing As5+ effectively over a short (10 min) reduction time using cysteine. An LOD of 42 pg f 1 following a 30 s depositioning was obtained. Initial studies also indicated the possibility of using the Au SPEs for measuring Cd, Pb and Cu, providing an alterative Hg-free procedure.Item Open Access Erosion hazard assessment in the upper Ewaso Ng’iro basin of Kenya: application of GIS, USLE and EUROSEM(1999-09-15) Mati, Bancy Mbura; Morgan, R. P. C.; Gichuki, F. N.; Quinton, J. N.; Brewer, Timothy R.; Liniger, H. P.A methodology was developed for assessing soil erosion hazard in the Upper Ewaso Ng’iro basin of Kenya, using Geographic Information Systems (GIS), the Universal Soil Loss Equation (USLE) and the European Soil Erosion Model (EUROSEM). The USLE was used in a GIS environment by creating thematic maps of R, K, L, S, C and P and then calculating soil loss by raster-grid modelling with Arc/Info GRID. The rainfall erosivity factor (R) was derived from relationships between rainfall amount and erosivity using erosion plot data from within the catchment. The nature of the relationship was found to be a function of agro-climatic zones of the region. Mean annual erosivities ranged from 145 to 990 J m'2 hr'1. For a given amount of rainfall, erosivity was higher in zone IV than in the wetter zones II-III. The soil erodibility factor (K) was estimated using the USLE nomograph and data from laboratory analysis of field samples collected from representative major soil mapping units. The K-values were low to medium, ranging from 0.10 to 0.25 over 84 percent of the basin. The topographic factor (LS) was obtained by creating Digital Elevation Models (DEMs) of the basin with TOPOGRIDTOOL of Arc/Info. These were then used to determine the slope steepness and length factor values, calculated with raster-grid modelling. Although DEMs proved a useful tool, maximum values of both steepness and length had to be set in this reconnaissance study to achieve reasonable results. A finer resolution of input data and a smaller grid cell size are needed for accurate determination. The cover and management factors (C) were obtained by determining the land cover types within the basin using remotely sensed data (SPOT 1 colour composite prints) and ground truthing studies. The factor values were estimated from USLE guide tables and measurements of cover from plots and test sites. Some 70 percent of the basin is covered by rangelands. The conservation practice (P) factor values were estimated from USLE guide tables and then applied to areas where soil conservation had been introduced according to maps obtained from the Ministry of Agriculture. The USLE was validated using data from erosion plots. A value of R2 = 0.645 was obtained between predicted and measured values but the standard error was rather high (e = 5.745 t ha’1 yr'1). Using an annual soil loss of 9.0 t ha'1 yr'1 as tolerance level, some 36 percent of the basin was found to experience unacceptably high erosion rates. Most of this area was communal grazing land and cropland where soil conservation measures had not been applied. A critical land cover type within the grazing land is shrubland, where vegetation cover is less than 40 percent and high erosion risk was predicted and confirmed by field surveys. EUROSEM could not be integrated within a GIS in the time available for research. It was therefore simulated outside GIS environment, where it was applied to Embori and Mukogodo plot data using separate data sets for calibration and validation. Calibration was used to obtain input parameters for saturated hydraulic conductivity, cohesion and Manning’s roughness coefficients. Validation gave correlation coefficients of 0.907 and 0.840 for predictions of storm runoff and soil loss respectively at Embori; the corresponding values for bare soil plots at Mukogodo were 0.895 and 0.577. However, EUROSEM predicted runoff poorly (R2 = 0.570) and failed to predict soil loss at all the vegetated plots at Mukogodo. The model was applied to simulated vegetation covers of barley, maize, grass and forest for a 36.7 mm rainstorm at Embori. The simulated soil losses showed an exponential decrease with increasing cover. At a threshold cover of 70 percent, soil loss diminished to zero under grass and forest and decreased to a minimum value under barley and maize. These results support the USLE simulations, which showed that areas with more than 70 percent cover (such as forest) had a low erosion hazard, even with steep slopes and high rainfall erosivities. This research has demonstrated that GIS can be used with the USLE to assess and quantify erosion hazard, giving results that can be used for conservation planning. EUROSEM can be applied successfully to bare soil and cropland, but application to other land covers requires further investigation. Land cover and topography are the main factors controlling the spatial distribution of soil loss in the Upper Ewaso Ng’iro basin. Future conservation activities should be concentrated on the rangelands.Item Open Access Ethical investment: An analysis trends in UK socially responsible investments funds(2004-09) Jones, Christopher; Robbins, PeterSocially Responsible Investment (SRI) is a growing sector in the financial world. SRI involves selecting and investing in stocks based on the ethical views of investors, and then screening, negatively and positively, companies for investment. Some of the ethical issues commonly addressed by SRI funds are alcohol, tobacco, gambling, and environmental and social issues. A model was adapted from Spillers 4 P’s for Ethical business to provide an analytical framework for generating qualitative theories about socially responsible investment (SRI). The aim of the thesis was to use this analytical framework as a starting point and develop/collapse it through constant comparison with data, in line with the grounded theory approach. Semi structured interviews were conducted with members of different groups with interests in SRI, and the transcriptions were coded using the qualitative data analysis software programme Atlas.ti. The results of the interviews confirm that the central driving force behind SRI is the investor, and this has been the case since SRIs inception. However, interviews with informants also reveal that there is an increasing influence from asset managers, as they recognise that SRI can provide a more sustainable form of investment. Changes in social attitudes about the role business plays in society are also behind an increasing desire to make corporations more accountable. Funds that use engagement as an investment strategy are trusted more by investors, because they are seen to have a greater commitment to socially responsible issues, but informants said that these funds need to be more transparent in their engagement policies. Many of the interviewees believed that there was a need for the integration of social, environmental, and ethical issues, with financial criteria when funds consider investment decisions.
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